@phdthesis{Baig2019, author = {Baig, Ayesha Anjum}, title = {Studies on platelet interactions with the coagulation system and on modulators of platelet (hem)ITAM signaling in genetically modified mice}, doi = {10.25972/OPUS-16488}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164888}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Activated platelets and coagulation jointly contribute to physiological hemostasis. However, pathological conditions can also trigger unwanted platelet activation and initiation of coagulation resulting in thrombosis and precipitation of ischemic damage of vital organs such as the heart or brain. The specific contribution of procoagulant platelets, positioned at the interface of the processes of platelet activation and coagulation, in ischemic stroke had remained uninvestigated. The first section of the thesis addresses this aspect through experiments conducted in novel megakaryocyte- and platelet-specific TMEM16F conditional KO mice (cKO). cKO platelets phenocopied defects in platelets from Scott Syndrome patients and had severely impaired procoagulant characteristics. This led to decelerated platelet-driven thrombin generation and delayed fibrin formation. cKO mice displayed prolonged bleeding times and impaired arterial thrombosis. However, infarct volumes in cKO mice were comparable to wildtype (WT) mice in an experimental model of ischemic stroke. Therefore, while TMEM16F-regulated platelet procoagulant activity is critical for hemostasis and thrombosis, it is dispensable for cerebral thrombo-inflammation in mice. The second section describes the generation and initial characterization of a novel knockin mouse strain that expresses human coagulation factor XII (FXII) instead of endogenous murine FXII. These knockin mice had normal occlusion times in an experimental model of arterial thrombosis demonstrating that human FXII is functional in mice. Therefore, these mice constitute a valuable tool for testing novel pharmacological agents against human FXII - an attractive potential target for antithrombotic therapy. Glycoprotein (GP)VI and C-type lectin-like receptor 2 (CLEC-2)-mediated (hem)immunoreceptor tyrosine-based activation motif (ITAM) signaling represent a major pathway for platelet activation. The last section of the thesis provides experimental evidence for redundant functions between the two members of the Grb2 family of adapter proteins - Grb2 and Gads that lie downstream of GPVI and CLEC-2 stimulation. In vitro and in vivo studies in mice deficient in both Grb2 and Gads (DKO) revealed that DKO platelets had defects in (hem)ITAM-stimulation-specific activation, aggregation and signal transduction that were more severe than the defects observed in single Grb2 KO or Gads KO mice. Furthermore, the specific role of these adapters downstream of (hem)ITAM signaling was essential for maintenance of hemostasis but dispensable for the known CLEC-2 dependent regulation of blood-lymphatic vessel separation.}, subject = {Blutgerinnung}, language = {en} } @phdthesis{HerbstgebHoehne2019, author = {Herbst [geb. H{\"o}hne], Stefanie}, title = {Liquid Crystalline Perylene Bisimide Assemblies}, doi = {10.25972/OPUS-16485}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164857}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Thus, the main focus of this thesis was to generate and investigate new one-dimensional LC PBI J-aggregates of an entirely new PBI organization with the transition dipole moments of the chromophores arranged parallel to the columnar axis and in slipped pi-pi stacking fashion to form highly fluorescent J-aggregates. Towards this goal, the tetra-bay substituted PBI 4c bearing free NH functional groups at the imide positions and four dendrons with branched ethylhexyl alkoxy chains at the meta-position of the phenoxy spacer (Figure 8.1a) was synthesized and compared to a literature known reference PBI 1. The mesogenic dendrons ensure LC character of the dye, which was confirmed by POM, DSC and extensive X-ray analysis. Furthermore, the sterically demanding bay-substituents prevent the cofacial assembly of the chromophores and force the dyes into a slipped pi-stacked order with the main transition dipole moments of the dyes oriented parallel to the columnar axis. X-ray analysis revealed that PBI 4c assembles into columnar triple-stranded helices consisting of side-to-side stacked molecules, which organize into a Colh phase (Figure 8.1b). FT-IR experiments of a thin film and aggregates in MCH solution confirmed the formation of H-bonds between the imide moieties. Temperature-dependent investigations furthermore proved a reversible formation of H-bonds and polarized FT-IR experiments finally gave evidence for the direction of the H-bonds along the shearing respective the columnar axis (Figure 8.1c). This was additionally verified by polarized UV-Vis absorption studies of aligned thin films. The changes in the UV-Vis absorption spectra of concentration- and temperature-dependent experiments in MCH are in agreement with the formation of J-aggregates and could be fitted to a nucleation-elongation growth mechanism. Remarkably, fluorescence spectroscopy studies revealed highly emissive aggregates in solution. These various spectroscopic techniques proved the utilization of directional noncovalent forces like hydrogen-bonding and pi-pi interactions in a cooperative manner forcing the PBI molecules in an unprecedented organization of a slipped pi-stacked arrangement with the orientation of the molecular axis and the respective transition dipole moments parallel to the columns of the LC phase. By the group of Dietrich the formation of exciton-polaritons in imprinted LC pillar microcavities as consequent use of the LC 4c was reported for the first time.In the second part of this thesis the hierarchical organization of LC PBIs into defined single-, double-, triple- and quadruple-stranded J-aggregates within crystalline and columnar LC phases, partially arranged in helical supramolecular structures in dependence of the molecular design was demonstrated. This was achieved via the preparation of a library of twelve molecules PBI 3-6(a-c) (Figure 8.2a) that was synthesized by varying the substitution position of the dendrons at the phenoxy-spacer from ortho to meta or para and by introducing an additional methyl group in ortho-position. Also the length and shape of the alkoxy chains was changed. Consequently, the impact of the sterical demand of the bay substituents concerning their phase properties, molecular arrangement and exciton coupling was investigated. POM, DSC and X-ray studies revealed the formation of only crystalline phase for the ortho-substituted PBIs 3a-c, whereas the other derivatives generated SC or LC phases. The main focus was the series with the n-C12-alkoxy chains. For the corresponding PBIs 4-6b columnar LC phases were confirmed. Retrostructural analysis by modelling and simulations gave indications for a single stranded organization for PBI 3b, a double-stranded helix for PBI 6b, a triple-stranded helical arrangement for PBI 5b and a quadruple-stranded helix for PBI 4b (Figure 8.2b-d). For all four derivatives the same molecular orientation within the columns as for PBI 4c was proven by polarized FT-IR and UV-Vis absorption studies in aligned thin films. The organization in helices of different number of strands in the Cr and LC phases of PBI 3b, 4b, 5b and 6b offered a unique possibility to elucidate the influence of particular packing arrangements on dye aggregate interactions with light. In particular, it can be investigated how exciton coupling of the dyes' transition dipole moments and fluorescence properties are affected. In this context, the spectroscopic properties were investigated in thin film, which revealed a strong bathochromic shift of the absorption maxima compared to the monomers in solution in dependence on the number of strands for PBIs 4-6b in contrast to PBI 3b (Figure 8.2e). The same tendency was observed for the respective aggregates in MCH solution. The spectral changes obtained during concentration- and temperature-dependent UV-Vis absorption studies verified the formation of J-aggregates in MCH solution and solid state. The respective aggregates are highly likely formed via a nucleation-elongation growth mechanism. Appliance of Kasha's exciton theory on the supramolecular aggregates revealed different contributions of H- and J-type coupling for the oligo-stranded helices. Under these considerations, it delivered an explanation for the absorption and fluorescence properties of the assemblies and declares the "best" J-aggregate for the double stranded arrangement of PBI 6b with purely negative couplings among neighbour molecules and a quantum yield above 74 \% of the aggregates in MCH solution. With this H-bonded PBI-based library approach of twelve derivatives it could be shown how molecular engineering of perylene bisimide dyes can be used to design defined, complex supramolecular assemblies with unprecedented packing patterns and concomitant intriguing spectroscopic properties. So far, the formation of defined liquid crystalline supramolecular structures of tetra-bay substituted PBIs by double H-bonding between free imide moieties and pi-pi interactions between the chromophores was demonstrated. The impact of the H-bonds on the molecular arrangement was investigated in the next part of this thesis. In this regard, PBIs 7 and 8 bearing a methyl or cyclohexyl group at the imide position (Figure 8.3a) were synthesized and compared to PBI 4c. The soft character of the solid state for PBIs 7 and 8 was confirmed by POM, DSC and X-ray analysis. The X-ray studies further revealed for both PBIs a change of the molecular assembly towards helical columnar structures of conventional pi-stacked chromophores (Figure 8.3b) when the directed H-bonds cannot contribute as noncovalent interactions to the assembly formation. Temperature-dependent UV-Vis absorption studies demonstrated the importance of H-bonding in MCH solution in the way that the formation of J-aggregates as for PBI 4c could not be observed for the imide substituted molecules. In the next step, the spectroscopic properties in thin film were investigated. For PBI 7 a J-type band and fluorescence spectra with an enlarged Stokes shift and increased fluorescence lifetime of 11.4 ns, compared to PBI 4c, was obtained, suggesting the generation of excimer type emission by considering the assumed conventional stacking of rotational displaced molecules from X-ray analysis. With polarized UV-Vis absorption experiments the orientation of the molecules perpendicular to the shearing direction and subsequently to the columnar axis was confirmed. These diverse investigations clearly demonstrated the imperative of H-bonds for stable, defined, LC J-aggregates with the transition dipole moments parallel to the columnar axis. With PBIs 7 and 8 it is impressively shown how small changes in the molecular structure influence the molecular arrangement dependent on the cooperation of non-covalent interactions like H-bonding and pi-pi stacking. In the last part of this thesis the generation of two-dimensional LC arrangements is presented. Since tetra-bay substituted PBIs lead always to twisted cores preventing lamellar arrangement, here 1,7-disubstitution and the simultaneous retention of the free imide positions was chosen to generate LC lamellar phases of PBIs 9a, 9b and 10 (Figure 8.4a). This molecular design was expected to form planar perylene cores that can strongly interact by pi-pi stacking and H-bonding. POM, DSC and X-ray investigations of the compounds suggest lamellar LC phases for PBIs 9a and 9b and a soft phase for PBI 10. In this regard, the goal of the formation of LC lamellar phase of PBIs could be attained. The change from dendrons with n-C12-alkoxy chains to large fork-like mesogens like in 9b clearly changed the phase properties. PBI 9b exhibits the lowest clearing point, high phase stability, least viscosity, easy shearability at room temperature and phase transitions between lamellar and Colh phases dependent on temperature. The formation of H-bonds parallel to the layers was demonstrated by polarized FT-IR experiments for all three PBIs. Concentration-dependent UV-Vis absorption studies revealed the formation of a J-type aggregate, which seems to exhibit an overall two-dimensional structure. With STM investigations the formation of lamellar structures from drop-casted 9a and 10 solutions in 1-phenyloctane on HOPG surface could be observed. Figure 8.4b illustrates a schematic possible arrangement of the molecules in the layers (here exemplarily demonstrated for PBI 9a), which has to be further confirmed by modelling and simulations. Unfortunately, fluorescence investigations of the thin films revealed non- or only slightly emissive LC states, which make them negligible for photonic applications. Nevertheless, the synthesized and analyzed compounds might be an inspiration for further investigations on the path to two-dimensional exciton transport for photonic devices.}, subject = {Fl{\"u}ssigkristall}, language = {en} } @phdthesis{Sauer2019, author = {Sauer, Markus}, title = {DHX36 function in RNA G-quadruplex-mediated posttranscriptional gene regulation}, doi = {10.25972/OPUS-18395}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-183954}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The expression of genetic information into proteins is a key aspect of life. The efficient and exact regulation of this process is essential for the cell to produce the correct amounts of these effector molecules to a given situation. For this purpose, eukaryotic cells have developed many different levels of transcriptional and posttranscriptional gene regulation. These mechanisms themselves heavily rely on interactions of proteins with associated nucleic acids. In the case of posttranscriptional gene regulation an orchestrated interplay between RNA-binding proteins, messenger RNAs (mRNA), and non-coding RNAs is compulsory to achieve this important function. A pivotal factor hereby are RNA secondary structures. One of the most stable and diverse representatives is the G-quadruplex structure (G4) implicated in many cellular mechanisms, such as mRNA processing and translation. In protein biosynthesis, G4s often act as obstacles but can also assist in this process. However, their presence has to be tightly regulated, a task which is often fulfilled by helicases. One of the best characterized G4-resolving factors is the DEAH-box protein DHX36. The in vitro function of this helicase is extensively described and individual reports aimed to address diverse cellular functions as well. Nevertheless, a comprehensive and systems-wide study on the function of this specific helicase was missing, so far. The here-presented doctoral thesis provides a detailed view on the global cellular function of DHX36. The binding sites of this helicase were defined in a transcriptome-wide manner, a consensus binding motif was deviated, and RNA targets as well as the effect this helicase exerts on them were examined. In human embryonic kidney cells, DHX36 is a mainly cytoplasmic protein preferentially binding to G-rich and G4-forming sequence motifs on more than 4,500 mRNAs. Loss of DHX36 leads to increased target mRNA levels whereas ribosome occupancy on and protein output of these transcripts are reduced. Furthermore, DHX36 knockout leads to higher RNA G4 levels and concomitant stress reactions in the cell. I hypothesize that, upon loss of this helicase, translationally-incompetent structured DHX36 target mRNAs, prone to localize in stress granules, accumulate in the cell. The cell reacts with basal stress to avoid cytotoxic effects produced by these mis-regulated and structured transcripts.}, subject = {RNS}, language = {en} } @phdthesis{Kremer2019, author = {Kremer, Antje}, title = {Tissue Engineering of a Vascularized Meniscus Implant}, doi = {10.25972/OPUS-18432}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-184326}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The knee joint is a complex composite joint containing the C-shaped wedge-like menisci composed of fibrocartilage. Due to their complex composition and structure, they provide mechanical resilience to the knee joint protecting the articular cartilage. Because of the limited repair potential, meniscal injuries do not only affect the meniscus itself but also lead to altered joint homeostasis and inevitably to secondary osteoarthritis. The meniscus was characterized focusing on its anatomy, structure and meniscal markers such as aggrecan, collagen type I (Col I) and Col II. The components relevant for meniscus tissue engineering, namely cells, Col I scaffolds, biochemical and biomechanical stimuli were studied. Meniscal cells (MCs) were isolated from meniscus, mesenchymal stem cells (MSCs) from bone marrow and dermal microvascular endothelial cells (d-mvECs) from foreskin biopsies. For the human (h) meniscus model, wedge-shape compression of a hMSC-laden Col I gel was successfully established. During three weeks of static culture, the biochemical stimulus transforming growth factor beta-3 (TGF beta-3) led to a compact collagen structure. On day 21, this meniscus model showed high metabolic activity and matrix remodeling as confirmed by matrix metalloproteinases detection. The fibrochondrogenic properties were illustrated by immunohistochemical detection of meniscal markers, significant GAG/DNA increase and increased compressive properties. For further improvement, biomechanical stimulation systems by compression and hydrostatic pressure were designed. As one vascularization approach, direct stimulation with ciclopirox olamine (CPX) significantly increased sprouting of hd-mvEC spheroids even in absence of auxiliary cells such as MSCs. Second, a cell sheet composed of hMSCs and hd-mvECs was fabricated by temperature triggered cell sheet engineering and transferred onto the wedge-shaped meniscus model. Third, a biological vascularized scaffold (BioVaSc-TERM) was re-endothelialized with hd-mvECs providing a viable vascularized network. The vascularized BioVaSc-TERM was suggested as wrapping scaffold of the meniscus model by using two suture techniques, the all-inside-repair (AIR) for the posterior horn, and the outside-in-refixation (OIR) for the anterior horn and the middle part. This meniscus model for replacing torn menisci is a promising approach to be further optimized regarding vascularization, biochemical and biomechanical stimuli.}, subject = {Meniskus}, language = {en} } @unpublished{Dandekar2019, author = {Dandekar, Thomas}, title = {Biological heuristics applied to cosmology suggests a condensation nucleus as start of our universe and inflation cosmology replaced by a period of rapid Weiss domain-like crystal growth}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-183945}, pages = {24}, year = {2019}, abstract = {Cosmology often uses intricate formulas and mathematics to derive new theories and concepts. We do something different in this paper: We look at biological processes and derive from these heuristics so that the revised cosmology agrees with astronomical observations but does also agree with standard biological observations. We show that we then have to replace any type of singularity at the start of the universe by a condensation nucleus and that the very early period of the universe usually assumed to be inflation has to be replaced by a period of rapid crystal growth as in Weiss magnetization domains. Impressively, these minor modifications agree well with astronomical observations including removing the strong inflation perturbations which were never observed in the recent BICEP2 experiments. Furthermore, looking at biological principles suggests that such a new theory with a condensation nucleus at start and a first rapid phase of magnetization-like growth of the ordered, physical laws obeying lattice we live in is in fact the only convincing theory of the early phases of our universe that also is compatible with current observations. We show in detail in the following that such a process of crystal creation, breaking of new crystal seeds and ultimate evaporation of the present crystal readily leads over several generations to an evolution and selection of better, more stable and more self-organizing crystals. Moreover, this explains the "fine-tuning" question why our universe is fine-tuned to favor life: Our Universe is so self-organizing to have enough offspring and the detailed physics involved is at the same time highly favorable for all self-organizing processes including life. This biological theory contrasts with current standard inflation cosmologies. The latter do not perform well in explaining any phenomena of sophisticated structure creation or self-organization. As proteins can only thermodynamically fold by increasing the entropy in the solution around them we suggest for cosmology a condensation nucleus for a universe can form only in a "chaotic ocean" of string-soup or quantum foam if the entropy outside of the nucleus rapidly increases. We derive an interaction potential for 1 to n-dimensional strings or quantum-foams and show that they allow only 1D, 2D, 4D or octonion interactions. The latter is the richest structure and agrees to the E8 symmetry fundamental to particle physics and also compatible with the ten dimensional string theory E8 which is part of the M-theory. Interestingly, any other interactions of other dimensionality can be ruled out using Hurwitz compositional theorem. Crystallization explains also extremely well why we have only one macroscopic reality and where the worldlines of alternative trajectories exist: They are in other planes of the crystal and for energy reasons they crystallize mostly at the same time, yielding a beautiful and stable crystal. This explains decoherence and allows to determine the size of Planck´s quantum h (very small as separation of crystal layers by energy is extremely strong). Ultimate dissolution of real crystals suggests an explanation for dark energy agreeing with estimates for the "big rip". The halo distribution of dark matter favoring galaxy formation is readily explained by a crystal seed starting with unit cells made of normal and dark matter. That we have only matter and not antimatter can be explained as there may be right handed mattercrystals and left-handed antimatter crystals. Similarly, real crystals are never perfect and we argue that exactly such irregularities allow formation of galaxies, clusters and superclusters. Finally, heuristics from genetics suggest to look for a systems perspective to derive correct vacuum and Higgs Boson energies.}, language = {en} } @phdthesis{Reinhard2019, author = {Reinhard, Julia}, title = {Developmental Aspects of Fear Learning and Fear Generalization}, doi = {10.25972/OPUS-16437}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164372}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {In situations of real threat, showing a fear reaction makes sense, thus, increasing the chance to survive. The question is, how could anybody differentiate between a real and an apparent threat? Here, the slogan counts "better safe than sorry", meaning that it is better to shy away once too often from nothing than once too little from a real threat. Furthermore, in a complex environment it is adaptive to generalize from one threatening situation or stimulus to another similar situation/stimulus. But, the danger hereby is to generalize in a maladaptive manner involving as it is to strong and/or fear too often "harmless" (safety) situations/stimuli, as it is known to be a criterion of anxiety disorders (AD). Fear conditioning and fear generalization paradigms are well suited to investigate fear learning processes. It is remarkable that despite increasing interest in this topic there is only little research on fear generalization. Especially, most research on human fear conditioning and its generalization has focused on adults, whereas only little is known about these processes in children, even though AD is typically developing during childhood. To address this knowledge gap, four experiments were conducted, in which a discriminative fear conditioning and generalization paradigm was used. In the first two experiments, developmental aspects of fear learning and generalization were of special interest. Therefore, in the first experiment 267 children and 285 adults were compared in the differential fear conditioning paradigm and generalization test. Skin conductance responses (SCRs) and ratings of valence and arousal were obtained to indicate fear learning. Both groups displayed robust and similar differential conditioning on subjective and physiological levels. However, children showed heightened fear generalization compared to adults as indexed by higher arousal ratings and SCRs to the generalization stimuli. Results indicate overgeneralization of conditioned fear as a developmental correlate of fear learning. The developmental change from a shallow to a steeper generalization gradient is likely related to the maturation of brain structures that modulate efficient discrimination between threatening and (ambiguous) safety cues. The question hereby is, at which developmental stage fear generalization gradients of children adapt to the gradients of adults. Following up on this question, in a second experiment, developmental changes in fear conditioning and fear generalization between children and adolescents were investigated. According to experiment 1 and previous studies in children, which showed changes in fear learning with increasing age, it was assumed that older children were better at discriminating threat and safety stimuli. Therefore, 396 healthy participants (aged 8 to 12 years) were examined with the fear conditioning and generalization paradigm. Again, ratings of valence, arousal, and SCRs were obtained. SCRs indicated differences in fear generalization with best fear discrimination in 12-year-old children suggesting that the age of 12 years seems to play an important role, since generalization gradients were similar to that of adults. These age differences were seen in boys and girls, but best discrimination was found in 12-year-old boys, indicating different development of generalization gradients according to sex. This result fits nicely with the fact that the prevalence of AD is higher in women than in men. In a third study, it was supposed that the developmental trajectory from increased trait anxiety in childhood to manifest AD could be mediated by abnormal fear conditioning and generalization processes. To this end, 394 children aged 8 to 12 years with different scores in trait anxiety were compared with each other. Results provided evidence that children with high trait anxiety showed stronger responses to threat cues and impaired safety signal learning contingent on awareness as indicated by arousal at acquisition. Furthermore, analyses revealed that children with high trait anxiety showed overall higher arousal ratings at generalization. Contrary to what was expected, high trait anxious children did not show significantly more fear generalization than children with low trait anxiety. However, high-trait-anxious (HA) participants showed a trend for a more linear gradient, whereas moderate-trait-anxious (MA) and low-trait-anxious (LA) participants showed more quadratic gradients according to arousal. Additionally, after controlling for age, sex and negative life experience, SCR to the safety stimulus predicted the trait anxiety level of children suggesting that impaired safety signal learning may be a risk factor for the development of AD. Results provide hints that frontal maturation could develop differently according to trait anxiety resulting in different stimuli discrimination. Thus, in a fourth experiment, 40 typically developing volunteers aged 10 to 18 years were screened for trait anxiety and investigated with the differential fear conditioning and generalization paradigm in the scanner. Functional magnetic resonance imaging (fMRI) were used to identify the neural mechanisms of fear learning and fear generalization investigating differences in this neural mechanism according to trait anxiety, developmental aspects and sex. At acquisition, HA participants showed reduced activation in frontal brain regions, but at generalization, HA participants showed an increase in these frontal regions with stronger linear increase in activation with similarity to CS+ in HA when compared to LA participants. This indicates that there is a hyper-regulation in adolescents to compensate the higher difficulties at generalization in form of a compensatory mechanism, which decompensates with adulthood and/or may be collapsed in manifest AD. Additionally, significant developmental effects were found: the older the subjects the stronger the hippocampus and frontal activation with resemblance to CS+, which could explain the overgeneralization of younger children. Furthermore, there were differences according to sex: males showed stronger activation with resemblance to CS+ in the hippocampus and frontal regions when compared to females fitting again nicely with the observation that prevalence rates for AD are higher for females than males. In sum, the studies suggest that investigating developmental aspects of (maladaptive) overgeneralization may lead to better understanding of the mechanisms of manifest anxiety disorders, which could result in development and provision of prevention strategies. Although, there is need for further investigations, the present work gives some first hints for such approaches.}, subject = {Furcht}, language = {en} } @phdthesis{Demmer2019, author = {Demmer, Claudia}, title = {Merger-specific Efficiency Gains}, doi = {10.25972/OPUS-18392}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-183928}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The present thesis analyzes whether and - if so - under which conditions mergers result in merger-specific efficiency gains. The analysis concentrates on manufacturing firms in Europe that participate in horizontal mergers as either buyer or target in the years 2005 to 2014. The result of the present study is that mergers are idiosyncratic processes. Thus, the possibilities to define general conditions that predict merger-specific efficiency gains are limited. However, the results of the present study indicate that efficiency gains are possible as a direct consequence of a merger. Efficiency changes can be measured by a Total Factor Productivity (TFP) approach. Significant merger-specific efficiency gains are more likely for targets than for buyers. Moreover, mergers of firms that mainly operate in the same segment are likely to generate efficiency losses. Efficiency gains most likely result from reductions in material and labor costs, especially on a short- and mid-term perspective. The analysis of conditions that predict efficiency gains indicates that firm that announce the merger themselves are capable to generate efficiency gains in a short- and mid-term perspective. Furthermore, buyers that are mid-sized firms are more likely to generate efficiency gains than small or large buyers. Results also indicate that capital intense firms are likely to generate efficiency gains after a merger. The present study is structured as follows. Chapter 1 motivates the analysis of merger-specific efficiency gains. The definition of conditions that reasonably likely predict when and to which extent mergers will result in merger-specific efficiency gains, would improve the merger approval or denial process. Chapter 2 gives a literature review of some relevant empirical studies that analyzed merger-specific efficiency gains. None of the empirical studies have analyzed horizontal mergers of European firms in the manufacturing sector in the years 2005 to 2014. Thus, the present study contributes to the existing literature by analyzing efficiency gains from those mergers. Chapter 3 focuses on the identification of mergers. The merger term is defined according to the EC Merger Regulation and the Horizontal Merger Guidelines. The definition and the requirements of mergers according to legislation provides the framework of merger identification. Chapter 4 concentrates on the efficiency measurement methodology. Most empirical studies apply a Total Factor Productivity (TFP) approach to estimate efficiency. The TFP approach uses linear regression in combination with a control function approach. The estimation of coefficients is done by a General Method of Moments approach. The resulting efficiency estimates are used in the analysis of merger-specific efficiency gains in chapter 5. This analysis is done separately for buyers and targets by applying a Difference-In-Difference (DID) approach. Chapter 6 concentrates on an alternative approach to estimate efficiency, that is a Stochastic Frontier Analysis (SFA) approach. Comparable to the TFP approach, the SFA approach is a stochastic efficiency estimation methodology. In contrast to TFP, SFA estimates the production function as a frontier function instead of an average function. The frontier function allows to estimate efficiency in percent. Chapter 7 analyses the impact of different merger- and firm-specific characteristics on efficiency changes of buyers and targets. The analysis is based on a multiple regression, which is applied for short-, mid- and long-term efficiency changes of buyers and targets. Chapter 8 concludes.}, subject = {Verarbeitende Industrie}, language = {en} } @phdthesis{Irmisch2019, author = {Irmisch, Linda}, title = {The role of septins and other regulatory proteins in abscission and midbody fate in C. elegans embryos}, doi = {10.25972/OPUS-18324}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-183244}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Abscission marks the last step of cytokinesis and gives rise to two physically separated daughter cells and a midbody remnant. This work studies abscission by examining the extent of the abscission failure in C. elegans septin and ESCRT mutants with the help of the ZF1-degradation technique. The ZF1 technique is also applied to discern a possible role for PI3K during abscission. Lastly, we test the role of proteins required for macroautophagy but not for LC3-associated phagocytosis (LAP) and show that after release into the extracellular space, the midbody is resolved via LAP.}, subject = {Zellteilung}, language = {en} } @phdthesis{MendesPereira2019, author = {Mendes Pereira, Lenon}, title = {Morphological and Functional Ultrashort Echo Time (UTE) Magnetic Resonance Imaging of the Human Lung}, doi = {10.25972/OPUS-18317}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-183176}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {In this thesis, a 3D Ultrashort echo time (3D-UTE) sequence was introduced in the Self-gated Non-Contrast-Enhanced Functional Lung Imaging (SENCEFUL) framework. The sequence was developed and implemented on a 3 Tesla MR scanner. The 3D-UTE technique consisted of a nonselective RF pulse followed by a koosh ball quasi-random sampling order of the k-space. Measurements in free-breathing and without contrast agent were performed in healthy subjects and a patient with lung cancer. A gating technique, using a combination of different coils with high signal correlation, was evaluated in-vivo and compared with a manual approach of coil selection. The gating signal offered an estimation of the breathing motion during measurement and was used as a reference to segment the acquired data into different breathing phases. Gradient delays and trajectory errors were corrected during post-processing using the Gradient Impulse Response Function. Iterative SENSE was then applied to determine the fully sampled data. In order to eliminate signal changes caused by motion, a 3D image registration was employed, and the results were compared to a 2D image registration method. Ventilation was assessed in 3D and regionally quantified by monitoring the signal changes in the lung parenchyma. Finally, image quality and quantitative ventilation values were compared to the standard 2D-SENCEFUL technique. 3D-UTE, combined with an automatic gating technique and SENCEFUL MRI, offered ventilation maps with high spatial resolution and SNR. Compared to the 2D method, UTE-SENCEFUL greatly improved the clinical quality of the structural images and the visualization of the lung parenchyma. Through-plane motion, partial volume effects and ventilation artifacts were also reduced with a three-dimensional method for image registration. UTE-SENCEFUL was also able to quantify regional ventilation and presented similar results to previous studies.}, subject = {Kernspintomografie}, language = {en} } @phdthesis{Turakhiya2019, author = {Turakhiya, Ankit}, title = {Functional characterization of the role of ZFAND1 in stress granule turnover}, doi = {10.25972/OPUS-16375}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-163751}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Protein quality control systems are critical for cellular proteostasis and survival under stress conditions. The ubiquitin proteasome system (UPS) plays a pivotal role in proteostasis by eliminating misfolded and damaged proteins. However, exposure to the environmental toxin arsenite results in the accumulation of polyubiquitylated proteins, indicating an overload of the UPS. Arsenite stress induces the rapid formation of stress granules (SGs), which are cytoplasmic assemblies of mRNPs stalled in translation initiation. The mammalian proteins ZFAND2A/B (also known as AIRAP and AIRAPL, respectively) bind to the 26S proteasome, and ZFAND2A has been shown to adapt proteasome activity to arsenite stress. They belong to a small subfamily of AN1 type zinc finger containing proteins that also comprises the unexplored mammalian member ZFAND1 and its yeast homolog Cuz1. In this thesis, the cellular function of Cuz1 and ZFAND1 was investigated. Cuz1/ZFAND1 was found to interact with the ubiquitin-selective, chaperone-like ATPase Cdc48/p97 and with the 26S proteasome. The interaction between Cuz1/ZFAND1 and Cdc48/p97 requires a predicted ubiquitin-like domain of Cuz1/ZFAND1. In vivo, this interaction was strongly dependent on acute arsenite stress, suggesting that it is a part of the cellular arsenite stress response. Lack of Cuz1/ZFAND1 caused a defect in the clearance of arsenite induced SG clearance. ZFAND1 recruits both, the 26S proteasome and p97, to arsenite-induced SGs for their normal clearance. In the absence of ZFAND1, SGs lack the 26S proteasome and p97, accumulate defective ribosomal products and become aberrant. These aberrant SGs persist after arsenite removal and undergo degradation via autophagy. ZFAND1 depletion is epistatic to the expression of pathogenic mutant p97 with respect to SG clearance, suggesting that ZFAND1 function is relevant to the multisystem degenerative disorder, inclusion body myopathy associated with Paget's disease of bone and frontotemporal dementia and amyotrophic lateral sclerosis (IBMPFD/ALS).}, subject = {ubiquitin}, language = {en} } @phdthesis{Breitenbach2019, author = {Breitenbach, Tim}, title = {A mathematical optimal control based approach to pharmacological modulation with regulatory networks and external stimuli}, doi = {10.25972/OPUS-17436}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-174368}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {In this work models for molecular networks consisting of ordinary differential equations are extended by terms that include the interaction of the corresponding molecular network with the environment that the molecular network is embedded in. These terms model the effects of the external stimuli on the molecular network. The usability of this extension is demonstrated with a model of a circadian clock that is extended with certain terms and reproduces data from several experiments at the same time. Once the model including external stimuli is set up, a framework is developed in order to calculate external stimuli that have a predefined desired effect on the molecular network. For this purpose the task of finding appropriate external stimuli is formulated as a mathematical optimal control problem for which in order to solve it a lot of mathematical methods are available. Several methods are discussed and worked out in order to calculate a solution for the corresponding optimal control problem. The application of the framework to find pharmacological intervention points or effective drug combinations is pointed out and discussed. Furthermore the framework is related to existing network analysis tools and their combination for network analysis in order to find dedicated external stimuli is discussed. The total framework is verified with biological examples by comparing the calculated results with data from literature. For this purpose platelet aggregation is investigated based on a corresponding gene regulatory network and associated receptors are detected. Furthermore a transition from one to another type of T-helper cell is analyzed in a tumor setting where missing agents are calculated to induce the corresponding switch in vitro. Next a gene regulatory network of a myocardiocyte is investigated where it is shown how the presented framework can be used to compare different treatment strategies with respect to their beneficial effects and side effects quantitatively. Moreover a constitutively activated signaling pathway, which thus causes maleficent effects, is modeled and intervention points with corresponding treatment strategies are determined that steer the gene regulatory network from a pathological expression pattern to physiological one again.}, subject = {Bioinformatik}, language = {en} } @article{RamlerPoaterHirschetal.2019, author = {Ramler, Jacqueline and Poater, Jordi and Hirsch, Florian and Ritschel, Benedikt and Fischer, Ingo and Bickelhaupt, F. Matthias and Lichtenberg, Crispin}, title = {Carbon monoxide insertion at a heavy p-block element: unprecedented formation of a cationic bismuth carbamoyl}, series = {Chemical Science}, volume = {10}, journal = {Chemical Science}, doi = {10.1039/C9SC00278B}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181627}, pages = {4169 - 4176}, year = {2019}, abstract = {Major advances in the chemistry of 5th and 6th row heavy p-block element compounds have recently uncovered intriguing reactivity patterns towards small molecules such as H\(_2\), CO\(_2\), and ethylene. However, well-defined, homogeneous insertion reactions with carbon monoxide, one of the benchmark substrates in this field, have not been reported to date. We demonstrate here, that a cationic bismuth amide undergoes facile insertion of CO into the Bi-N bond under mild conditions. This approach grants direct access to the first cationic bismuth carbamoyl species. Its characterization by NMR, IR, and UV/vis spectroscopy, elemental analysis, single-crystal X-ray analysis, cyclic voltammetry, and DFT calculations revealed intriguing properties, such as a reversible electron transfer at the bismuth center and an absorption feature at 353 nm ascribed to a transition involving σ- and π-type orbitals of the bismuth-carbamoyl functionality. A combined experimental and theoretical approach provided insight into the mechanism of CO insertion. The substrate scope could be extended to isonitriles.}, language = {en} } @phdthesis{Roedel2019, author = {R{\"o}del, Michaela}, title = {Development of Dual Setting Cement Systems as Composite Biomaterials with Ductile Properties}, doi = {10.25972/OPUS-18277}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-182776}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Synthetic bone replacement materials have their application in non-load bearing defects with the function of (re-)construction or substitution of bone. This tissue itself represents a biological composite material based on mineralized collagen fibrils and combines the mechanical strength of the mineral with the ductility of the organic matrix. By mimicking these outstanding properties with polymer-cement-composites, an imitation of bone is feasible. A promising approach for such replacement materials are dual setting systems, which are generated by dissolution-precipitation reaction with cement setting in parallel to polymerization and gelation of the organic phase forming a coherent hydrogel network. Hereby, the high brittleness of the pure inorganic network was shifted to a more ductile and elastic behavior. The aim of this thesis was focused on the development of different dual setting systems to modify pure calcium phosphate cements' (CPCs') mechanical performance by incorporation of a hydrogel matrix. A dual setting system based on hydroxyapatite (HA) and cross-linked 2-hydroxyethyl methacrylate (HEMA) via radical polymerization was advanced by homogenous incorporation of a degradable cross-linker composed of poly(ethylene glycol) (PEG) as well as poly(lactic acid) (PLA) with reactive terminal methacrylate functionalities (PEG-PLLA-DMA). By integration of this high molecular weight structure in the HEMA-hydrogel network, a significant increase in energy absorption (toughness) under 4-point bending testing was observed. An addition of only 10 wt\% hydrogel precursor (referred to the liquid phase) resulted in a duplication of stress over a period of 8 days. Additionally, the calculated elasticity was positively affected and up to six times higher compared to pure HA. With a constantly applied force during compressive strength testing, a deformation and thus strain levels of about 10 \% were reached immediately after preparation. For higher degradability, the system was modified in a second approach regarding organic as well as inorganic phase. The latter component was changed by brushite forming cement that is resorbable in vivo due to solubility processes. This CPC was combined with a hydrogel based on PEG-PLLA-DMA and other dimethacrylated PEGs with different molecular weights and concentrations. Hereby, new reaction conditions were created including a shift to acidic conditions. On this ground, the challenge was to find a new radical initiator system. Suitable candidates were ascorbic acid and hydrogen peroxide. that started the polymerization and successful gelation in this environment. These highly flexible dual set composites showed a very high ductility with an overall low strength compared to HA-based models. After removal of the applied force during compressive strength testing, a complete shape recovery was observed for the samples containing the highest polymeric amount (50 wt\%) of PEG-PLLA-DMA. Regarding phase distribution in the constructs, a homogenously incorporated hydrogel network was demonstrated in a decalcifying study with ethylenediaminetetraacetic acid. Intact, coherent hydrogels remained after dissolution of the inorganic phase via calcium ion complexation. In a third approach, the synthetic hydrogel matrix of the previously described system was replaced by the natural biopolymer gelatin. Simultaneously to brushite formation, physical as well as chemical cross-linking by the compound genipin was performed in the dual setting materials. Thanks to the incorporation of gelatin, elasticity increased significantly, in which concentrations up to 10.0 w/v\% resulted in a certain cohesion of samples after compressive strength testing. They did not dissociate in little pieces but remained intact cuboid specimens though having cracks or fissures. Furthermore, the drug release of two active pharmaceutical ingredients (vancomycin and rifampicin) was investigated over a time frame of 5 weeks. The release exponent was determined according to Korsmeyer-Peppas with n = 0.5 which corresponds to the drug liberation model of Higuchi. A sustained release was observed for the antibiotic vancomycin encapsulated in composites with a gelatin concentration of 10.0 w/v\% and a powder-to-liquid ratio of 2.5 g/mL. With respect to these developments of different dual setting systems, three novel approaches were successfully established by polymerization of monomers and cross-linking of precursors forming an incorporated, homogenous hydrogel matrix in a calcium phosphate network. All studies showed an essential transfer of mechanical performance in direction of flexibility and bendability.}, subject = {Calciumphosphate}, language = {en} } @phdthesis{Brill2019, author = {Brill, Michael}, title = {Spontaneous eye blinks as an alternative measure for spatial presence experiences}, edition = {1. Auflage}, publisher = {W{\"u}rzburg University Press}, address = {W{\"u}rzburg}, isbn = {978-3-95826-094-8}, doi = {10.25972/WUP-978-3-95826-095-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167898}, school = {W{\"u}rzburg University Press}, pages = {xvi, 265}, year = {2019}, abstract = {Spatial presence, a state in which media users temporarily overlook the mediated nature of their media use experience, is frequently assessed by means of post-session self-report scales. However, such methods have methodical limitations, for example concerning measurement of dynamic fluctuations in presence during media use. Consequently, researchers have tested several approaches that try to infer subjective experiences of spatial presence from objectively measurable indicators. The present doctoral thesis examines aspects of temporal structure in spontaneous eye-blink behavior. Cognitive processes—and especially attention—are seen as essential antecedents of presence experiences. Because such cognitive processes influence timing of spontaneous eye-blinks, it is tested if the degree of stimulus-dependent structure in spontaneous eye-blink behavior is related to presence self-report scores. To address this research question, the thesis first establishes a theoretical framework, including theorizing and empirical findings on presence, on related media use phenomena, spontaneous eye-blink behavior, and subjective and objective approaches for presence assessment. Then, three experiments are presented that examine the relation between self-reported presence, and amount of stimulus-dependent structure in blinking behavior. Three different methods for quantification of stimulus-dependent structure are tested in different media environments, and are related to an established presence scale. Discussion of the experimental findings leads, on the one hand, to fundamental questions on the presence concept and on the understanding of stimulus-dependent structure in spontaneous eye-blink behavior. On the other hand, interpretation of the results emphasizes the necessity for methods with appropriate temporal resolution, that consider both media events and user behavior.}, subject = {Lidschlag}, language = {en} } @phdthesis{Reggane2019, author = {Reggane, Maude}, title = {Lowering lattice forces of crystalline bases}, doi = {10.25972/OPUS-16380}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-163803}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The number of active pharmaceutical ingredients (APIs) exhibiting a low solubility in aqueous media or a slow dissolution rate kept rising over the past years urging formulation scientists to explore new ways to tackle poor solubility and to enable oral absorption from such compounds. Bioavailability of poorly water-soluble compounds can be improved by increasing the dissolution rate and/or by increasing the gastro intestinal concentration through transient supersaturation. The dissolution rate of the API can be typically modified by the choice of the physical form, the polymorphic form, the powder surface area, and the local pH, while a transient supersaturation can be extended mainly by nucleation or crystallization inhibiting effects. In the present thesis, three strategies were explored to tailor the dissolution rate, the supersaturation and the hydrotropic solubilization of APIs, weak bases, respectively. The first part of this thesis followed a bioinspired approach to extend the kinetic solubility of salts and co-crystals. API salts and co-crystals are high energy forms that can generate supersaturated solutions with respect to any more stable form, typically the most stable API form in physiological environment. The transient kinetic stabilization of supersaturated states, also termed "parachute effect", is considered to improve bioavailability and is one aspect of the formulation that can be tailored. Inspiration from plants, which store high concentrations of aromatic bases in their vacuoles via complexation with polyphenols, sparked the evaluation to use hydroxybenzoic acid derivatives for salt or co-crystal engineering. Imatinib was chosen as the model compound for this investigation as its aromaticity and flat molecular architecture could favor interactions with hydroxybenzoic acid derivatives. One 1:1 Imatinib syringate co-crystal (I-SYA (1:1)) and one 1:2 Imatinib syringate co-crystal salt (I-SYA (1:2)) were obtained. Their dissolution assays in simulated intestinal fluid (SIF; a 50 mM phosphate buffer of pH 6.8) revealed that they formed stable solutions for several hours and days, respectively, in contrast to the marketed Imatinib mesylate salt (approx. 1h). This kinetic stability in solution was linked to the nucleation inhibition of the less soluble Imatinib hydrate by syringic acid (SYA). In solution 1H-NMR studies evidenced the aggregation of Imatinib and SYA. The amphiphilic nature of both Imatinib and SYA is considered to drive their association in solution, additionally, multiple intermolecular interactions such as hydrogen bonds and π-π stacking are likely to contribute. The association in solution enabled a phase of extended supersaturation, i.e., a parachute against desupersaturation, while no negative impact of aggregation on the permeability of both Imatinib and SYA was observed. A prerequisite to reach supersaturation is a rapid dissolution and release of the API from the formulation. Accordingly, the second and third part of this thesis is focused on the so-called "spring effect" of amorphous solid dispersions (ASDs). The addition of a hydrotropic agent, meaning a molecule that can solubilize poorly water-soluble APIs in aqueous solutions (well-known examples of hydrotropes are benzoic acid and nicotinamide) into an amorphous Ciprofloxacin-polymer matrix led to ternary systems with a significantly faster release and higher concentration of the API in SIF as compared to binary ASDs consisting of Ciprofloxacin (CPX) and polymer only. The stronger spring could be rationalized by an improved wetting of the ASD, or/and by a hydrotropic solubilization effect, although these hypotheses need further investigation. Marked differences in the dissolution profiles of binary ASDs were observed in biorelevant fasted simulated intestinal fluid (FaSSIF; a medium containing Na taurocholate (3 mM) and lecithin (0.75 mM) at pH 6.5) as compared to SIF. In FaSSIF, API release from binary polymeric ASDs was largely improved, and the duration of supersaturation was extended. This suggests that the bile salt Na taurocholate and lecithin present in FaSSIF do improve both dissolution rate and supersaturation of ASDs, the two pillars of ASDs as oral enabling formulations. Indeed, bile salts are endogenous surfactants which, together with phospholipids, play an important role in the wetting, solubilization, and absorption of lipophilic compounds. The aim of the third part of the present thesis was to study ASDs as formulation principles reducing the strong positive food effect of Compound A. By inclusion of Na taurocholate (NaTC) within the matrix of polymeric ASDs a significant improvement of the dissolution rate and the kinetic solubility in SIF were achieved. Transient supersaturated states of up to four orders of magnitude over the equilibrium solubility were obtained. Two ASDs were selected for further in vivo evaluation in dog. The first was a NaTC/Eudragit E based ASD meant to dissolve and release Compound A in the acidic environment of the stomach, where its solubility is the highest. The second relied on the release of Compound A in the neutral environment of the duodenum and jejunum by using an enterically dissolving polymer, HPMC-P. Releasing the API at the site of its putative absorption was an attempt to control supersaturation levels in the duodenum and to prevent portioning and thus dilution effects during transfer from the stomach. In fasted dogs, exposure from the NaTC/HPMC-P ASD was close to that of the reference Compound A formulation under fed conditions, which suggests an improved dissolution rate and kinetic solubility under fasted conditions (historical data). The exposure from the NaTC/Eudragit E ASD was twice as low as from the NaTC/HPMC-P ASD, and also lower compared to Compound A reference formulation, whereas in vitro the parachute effect of the NaTC/Eudragit E ASD was largely superior to that of the NaTC/HPMC-P ASD. A difference in the extend of the parachute could be related to differences in the thermodynamic activity of dissolved molecules from the two ASDs. Indeed, the high instability of the NaTC/HPMC-P ASD could stem from a high thermodynamic activity driving diffusion through membranes, whereas less instable solutions of NaTC/Eudragit E could indicate solubilization effects which often translate into a lower flux through the biological membrane. Additionally, the pH of the environment where dissolution takes place might be an important factor for absorption, and could also account for the difference in exposure from the two ASDs. The aim of this thesis was to explore how the intimate environment of weak, poorly soluble bases could be functionalized to improve dissolution rate and kinetic solubility. The investigations highlighted that the performance of enabling oral delivery formulations of weak bases in aqueous media can be enhanced at different levels. At one end initial dissolution rate of ASDs can be tailored by introducing hydrotropes or/and bile salts within the polymeric matrix of ASDs. Bile salts, when combined with appropriate polymers, had also a precipitation inhibition effect enabling the maintenance of supersaturation for a bio-relevant period of time. These results set the ground for further investigations to comprehend specific interactions between bile salts and APIs, and potentially polymers at the molecular level. It will be interesting to explore how such complex systems can be exploited in the formulation design of poorly water-soluble APIs. In addition, it was observed that the duration of supersaturation generated by salts/co-crystals can be extended by the pertinent selection of counterions or coformers. The in vivo relevance of these tunings remains to be evaluated, as translation from closed, in vitro systems to the highly dynamic gastrointestinal environment is not straightforward. A better understanding of the contribution of each kinetic stage (dissolution, supersaturation, and precipitation) and their interplay with physiological factors impacting absorption is essential to facilitate the design of formulations with improved pharmacokinetics.}, subject = {Kokristallisation}, language = {en} } @phdthesis{Nieberler2019, author = {Nieberler, Matthias}, title = {The physiological role of autoproteolysis of the Adhesion GPCR Latrophilin/dCIRL}, doi = {10.25972/OPUS-16589}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165894}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {G protein-coupled receptors of the Adhesion family (aGPCRs) comprise the second largest group within the GPCR realm with over 30 mammalian homologs. They contain a unique structure with unusually large extracellular domains (ECDs) holding many structural folds known to mediate cell-cell and cell-matrix interactions. Furthermore, aGPCRs undergo autoproteolytic cleavage at the GPCR proteolysis site (GPS), an integral portion of the GPCR autoproteolysis inducing (GAIN) domain. Thus far, it is largely unknown if and how self-cleavage affects aGPCR activation and signaling and how these signals may shape the physiological function of cells. Latrophilin, alternatively termed the calcium-independent receptor of α-latrotoxin (CIRL) constitutes a highly conserved, prototypic aGPCR and has been assigned roles in various biological processes such as synaptic development and maturation or the regulation of neurotransmitter release. The Drosophila melanogaster homolog dCIRL is found in numerous sensory neurons including the mechanosensory larval pentascolopidial chordotonal organs (CHOs), which rely on dCIRL function in order to sense mechanical cues and to modulate the mechanogating properties of present ionotropic receptors. This study reveals further insight into the broad distribution of dCirl expression throughout the larval central nervous system, at the neuromuscular junction (NMJ), as well as subcellular localization of dCIRL in distal dendrites and cilia of chordotonal neurons. Furthermore, targeted mutagenesis which disabled GPS cleavage of dCIRL left intracellular trafficking in larval CHOs unaffected and proved autoproteolysis is not required for dCIRL function in vivo. However, substitution of a threonine residue, intrinsic to a putative tethered agonist called Stachel that has previously been documented for several other aGPCRs, abrogated receptor function. Conclusively, while this uncovered the presence of Stachel in dCIRL, it leaves the question about the biological relevance of the predetermined breaking point at the GPS unanswered. In an independent approach, the structure of the "Inter-RBL-HRM" (IRH) region, the region linking the N-terminal Rhamnose-binding lectin-like (RBL) and the hormone receptor motif (HRM) domains of dCIRL, was analyzed. Results suggest random protein folding, excessive glycosylation, and a drastic expansion of the size of IRH. Therefore, the IRH might represent a molecular spacer ensuring a certain ECD dimension, which in turn may be a prerequisite for proper receptor function. Taken together, the results of this study are consistent with dCIRL's mechanoceptive faculty and its role as a molecular sensor that translates mechanical cues into metabotropic signals through a yet undefined Stachel-dependent mechanism.}, subject = {Latrophilin}, language = {en} } @phdthesis{Rydzek2019, author = {Rydzek, Julian}, title = {NF-κB/NFAT Reporter Cell Platform for Chimeric Antigen Receptor (CAR)-Library Screening}, doi = {10.25972/OPUS-17918}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-179187}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Immunotherapy with engineered T cells expressing a tumor-specific chimeric antigen receptor (CAR) is under intense preclinical and clinical investigation. This involves a rapidly increasing portfolio of novel target antigens and CAR designs that need to be tested in time- and work-intensive screening campaigns in primary T cells. Therefore, we anticipated that a standardized screening platform, similar as in pharmaceutical small molecule and antibody discovery, would facilitate the analysis of CARs by pre-selecting lead candidates from a large pool of constructs that differ in their extracellular and intracellular modules. Because CARs integrate structural elements of the T cell receptor (TCR) complex and engage TCR-associated signaling molecules upon stimulation, we reasoned that the transcription factors nuclear factor-κB (NF-κB) and nuclear factor of activated T cells (NFAT) could serve as surrogate markers for primary T cell function. The nuclear translocation of both transcription factors in primary T cells, which we observed following CAR stimulation, supported our rationale to use NF-κB and NFAT as indicators of CAR-mediated activation in a screening platform. To enable standardized and convenient analyses, we have established a CAR-screening platform based on the human T cell lymphoma line Jurkat that has been modified to provide rapid detection of NF-κB and NFAT activation. For this purpose, Jurkat cells contained NF-κB and NFAT-inducible reporter genes that generate a duplex output of cyan fluorescent protein (CFP) and green fluorescent protein (GFP), respectively. Upon stimulation of NF-κB/NFAT reporter cells, the expression of both fluorophores could be readily quantified in high-throughput screening campaigns by flow cytometry. We modified the reporter cells with CD19-specific and ROR1-specific CARs, and we co-cultured them with antigen-positive stimulator cells to analyze NF-κB and NFAT activation. CAR-induced reporter signals could already be detected after 6 hours. The optimal readout window with high-level reporter activation was set to 24 hours, allowing the CAR-screening platform to deliver results in a rapid turnaround time. A reporter cell-screening campaign of a spacer library with CARs comprising a short, intermediate or long IgG4-Fc domain allowed distinguishing functional from non-functional constructs. Similarly, reporter cell-based analyses identified a ROR1-CAR with 4-1BB domain from a library with different intracellular signal modules due to its ability to confer high NF-κB activation, consistent with data from in vitro and in vivo studies with primary T cells. The results of both CAR screening campaigns were highly reproducible, and the time required for completing each testing campaign was substantially shorter with reporter cells (6 days) compared to primary T cells (21 days). We further challenged the reporter cells in a large-scale screening campaign with a ROR1 CAR library comprising mutations in the VH CDR3 sequence of the R11 scFv. This region is crucial for binding the R11 epitope of ROR1, and we anticipated that mutations here would cause a loss of specificity and affinity for most of the CAR variants. This provided the opportunity to determine whether the CAR screening platform was able to retrieve functional constructs from a large pool of CAR variants. Indeed, using a customized pre enrichment and screening strategy, the reporter cells identified a functional CAR variant that was present with a frequency of only 6 in 1.05x10^6. As our CAR-screening platform enabled the analysis of activating signal modules, it encouraged us to also evaluate inhibitory signal modules that change the CAR mode of action. Such an inhibitory CAR (iCAR) can be used in logic gates with an activating CAR to interfere with T cell stimulation. By selecting appropriate target antigens for iCAR and CAR, this novel application aims to improve the selectivity towards tumor cells, and it could readily be studied using our screening platform. Accordingly, we tested CD19-specific iCARs with inhibitory PD-1 signal module for their suppressive effect on reporter gene activation. In logic gates with CAR or TCR stimulation, a decrease of NF-κB and NFAT signals was only observed when activating and inhibitory receptors were forced into spatial proximity. These results were further verified by experiments with primary T cells. In conclusion, our reporter cell system is attractive as a platform technology because it is independent of testing in primary T cells, exportable between laboratories, and scalable to enable small- to large-scale screening campaigns of CAR libraries. The pre-selection of appropriate lead candidates with optimal extracellular and intracellular modules can reduce the number of CAR constructs to be investigated in further in vitro and in vivo studies with primary T cells. We are therefore confident that our CAR-screening platform based on NF-κB/NFAT reporter cells will be useful to accelerate translational research by facilitating the evaluation of CARs with novel design parameters.}, subject = {Antigenrezeptor}, language = {en} } @phdthesis{SchmittgebWolf2019, author = {Schmitt [geb. Wolf], Karen}, title = {Studies on the role of platelet serotonin in platelet function, hemostasis, thrombosis and stroke}, doi = {10.25972/OPUS-13471}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134711}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Platelet activation and aggregation are important processes in hemostasis resulting in reduction of blood loss upon vessel wall injury. However, platelet activation can lead to thrombotic events causing myocardial infarction and stroke. A more detailed understanding of the regulation of platelet activation and the subsequent formation of thrombi is essential to prevent thrombosis and ischemic stroke. Cations, platelet surface receptors, cytoskeletal rearrangements, activation of the coagulation cas-cade and intracellular signaling molecules are important in platelet activation and thrombus formation. One such important molecule is serotonin (5 hydroxytryptamin, 5 HT), an indolamine platelet agonist, biochemically derived from tryptophan. 5 HT is secreted from the enterochromaffin cells into the gastrointestinal tract (GI) and blood. Blood borne 5 HT has been proposed to regulate hemostasis by acting as a vaso-constrictor and by triggering platelet signaling through 5 HT2A receptor. Although platelets do not synthetize 5 HT, they take it up from the blood and store it in their dense granules which are secreted upon platelet activation. To identify the molecu-lar composite of the 5 HT uptake system in platelets and elucidate the role of platelet released 5-HT in thrombosis and ischemic stroke, 5 HT transporter knock out mice (5Htt / ) were analyzed in different in vitro and in vivo assays and in a model of is-chemic stroke. In 5Htt / platelets, 5 HT uptake from the blood was completely abol-ished and agonist-induced Ca2+ influx through store operated Ca2+ entry (SOCE), integrin activation, degranulation and aggregation responses to glycoprotein (GP) VI and C type lectin-like receptor 2 (CLEC 2) were reduced. These observed in vitro defects in 5Htt / platelets could be normalized by the addition of exogenous 5 HT. Moreover, reduced 5 HT levels in the plasma, an increased bleeding time and the formation of unstable thrombi were observed ex vivo under flow and in vivo in the abdominal aorta and carotid artery of 5Htt / mice. Surprisingly, in the transient middle cerebral artery occlusion model (tMCAO) of ischemic stroke 5Htt / mice showed near-ly normal infarct volumes and a neurological outcome comparable to control mice. Although secreted platelet 5 HT does not appear to play a crucial role in the devel-opment of reperfusion injury after stroke, it is essential to amplify the second phase of platelet activation through SOCE and thus plays an important role in thrombus stabilization. To further investigate the role of cations, granules and their contents and regulation of integrin activation in the process of thrombus formation, genetically modified mice were analyzed in the different in vivo thrombosis models. Whereas Tph1 / mice (lacking the enzyme responsible for the production of 5 HT in the periphery), Trpm7KI (point mu-tation in the kinase domain of Trpm7 channel, lacking kinase activity) and Unc13d / /Nbeal2 / mice (lacking α granules and the release machinery of dense granules) showed a delayed thrombus formation in vivo, MagT1y/ mice (lacking a specific Mg2+ transporter) displayed a pro thrombotic phenotype in vivo. Trpm7fl/fl Pf4Cre (lacking the non specific Mg2+ channel) and RIAM / mice (lacking a potential linker protein in integrin "inside out" signaling) showed no alterations in thrombus formation upon injury of the vessel wall.}, subject = {Serotonin}, language = {en} } @phdthesis{Uri2019, author = {Uri, Anna}, title = {Differential requirement for CD28 co-stimulation on donor T cell subsets in mouse models of acute graft versus host disease and graft versus tumour effect}, doi = {10.25972/OPUS-16586}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165863}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Hematopoietic stem cell transplantation is a curative therapy for malignant diseases of the haematopoietic system. The patients first undergo chemotherapy or irradiation therapy which depletes the majority of tumour cells before they receive the transplant, consisting of haematopoietic stem cells and mature T cells from a healthy donor. The donor T cells kill malignant cells that have not been eliminated by the conditioning therapy (graft versus leukaemia effect, GvL), and, therefore, are crucially required to prevent relapse of the tumour. However, the donor T cells may also severely damage the patient's organs causing acute graft versus host disease (aGvHD). In mice, aGvHD can be prevented by interfering with the co-stimulatory CD28 signal on donor T cells. However, experimental models using conventional CD28 knockout mice as T cell donors or αCD28 antibodies have some disadvantages, i.e. impaired T cell development in the thymus of CD28 knockout mice and systemic CD28 blockade with αCD28 antibodies. Thus, it remains unclear how CD28 co-stimulation on different donor T cell subsets contributes to the GvL effect and aGvHD, respectively. We developed mouse models of aGvHD and the GvL effect that allowed to selectively delete CD28 on certain donor T cell populations or on all donor T cells. CD4+ conventional T cells (Tconv cells), regulatory T cells (Treg cells) or CD8+ T cells were isolated from either Tamoxifen-inducible CD28 knockout (iCD28KO) mice or their wild type (wt) littermates. Allogeneic recipient mice were then transplanted with T cell depleted bone marrow cells and different combinations of iCD28KO and wt T cell subsets. Tamoxifen treatment of the recipients caused irreversible CD28 deletion on the iCD28KO donor T cell population. In order to study the GvL response, BCL-1 tumour cells were injected into the mice shortly before transfer of the T cells. CD4+ Tconv mediated aGvHD was efficiently inhibited when wt Treg cells were co-transplanted. In contrast, after selective CD28 deletion on donor Treg cells, the mice developed a late and lethal flare of aGvHD, i.e. late-onset aGvHD. This was associated with a decline in iCD28KO Treg cell numbers around day 20 after transplantation. CD28 ablation on either donor CD4+ Tconv cells or CD8+ T cells reduced but did not abrogate aGvHD. Moreover, iCD28KO and wt CD8+ T cells were equally capable of killing allogeneic target cells in vivo and in vitro. Due to this sufficient anti-tumour activity of iCD28KO CD8+ T cells, they had a therapeutic effect in our GvL model and 25\% of the mice survived until the end of the experiment (day 120) without any sign of the malignant disease. Similarly, CD28 deletion on all donor T cells induced long-term survival. This was not the case when all donor T cells were isolated from wt donor mice. In contrast to the beneficial outcome after CD28 deletion on all donor T cells or only CD8+ T cells, selective CD28 deletion on donor CD4+ Tconv cells completely abrogated the GvL effect due to insufficient CD4+ T cell help from iCD28KO CD4+ Tconv cells. This study demonstrates that therapeutic inhibition of the co-stimulatory CD28 signal in either all donor T cells or only in CD8+ T cells might protect patients from aGvHD without increasing the risk of relapse of the underlying disease. Moreover, deletion of CD28 on donor Treg cells constitutes a mouse model of late-onset aGvHD which can be a useful tool in aGvHD research.}, subject = {Antigen CD28}, language = {en} } @phdthesis{Breitenbach2019, author = {Breitenbach, Tim}, title = {A sequential quadratic Hamiltonian scheme for solving optimal control problems with non-smooth cost functionals}, doi = {10.25972/OPUS-18217}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-182170}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {This thesis deals with a new so-called sequential quadratic Hamiltonian (SQH) iterative scheme to solve optimal control problems with differential models and cost functionals ranging from smooth to discontinuous and non-convex. This scheme is based on the Pontryagin maximum principle (PMP) that provides necessary optimality conditions for an optimal solution. In this framework, a Hamiltonian function is defined that attains its minimum pointwise at the optimal solution of the corresponding optimal control problem. In the SQH scheme, this Hamiltonian function is augmented by a quadratic penalty term consisting of the current control function and the control function from the previous iteration. The heart of the SQH scheme is to minimize this augmented Hamiltonian function pointwise in order to determine a control update. Since the PMP does not require any differ- entiability with respect to the control argument, the SQH scheme can be used to solve optimal control problems with both smooth and non-convex or even discontinuous cost functionals. The main achievement of the thesis is the formulation of a robust and efficient SQH scheme and a framework in which the convergence analysis of the SQH scheme can be carried out. In this framework, convergence of the scheme means that the calculated solution fulfills the PMP condition. The governing differential models of the considered optimal control problems are ordinary differential equations (ODEs) and partial differential equations (PDEs). In the PDE case, elliptic and parabolic equations as well as the Fokker-Planck (FP) equation are considered. For both the ODE and the PDE cases, assumptions are formulated for which it can be proved that a solution to an optimal control problem has to fulfill the PMP. The obtained results are essential for the discussion of the convergence analysis of the SQH scheme. This analysis has two parts. The first one is the well-posedness of the scheme which means that all steps of the scheme can be carried out and provide a result in finite time. The second part part is the PMP consistency of the solution. This means that the solution of the SQH scheme fulfills the PMP conditions. In the ODE case, the following results are obtained that state well-posedness of the SQH scheme and the PMP consistency of the corresponding solution. Lemma 7 states the existence of a pointwise minimum of the augmented Hamiltonian. Lemma 11 proves the existence of a weight of the quadratic penalty term such that the minimization of the corresponding augmented Hamiltonian results in a control updated that reduces the value of the cost functional. Lemma 12 states that the SQH scheme stops if an iterate is PMP optimal. Theorem 13 proves the cost functional reducing properties of the SQH control updates. The main result is given in Theorem 14, which states the pointwise convergence of the SQH scheme towards a PMP consistent solution. In this ODE framework, the SQH method is applied to two optimal control problems. The first one is an optimal quantum control problem where it is shown that the SQH method converges much faster to an optimal solution than a globalized Newton method. The second optimal control problem is an optimal tumor treatment problem with a system of coupled highly non-linear state equations that describe the tumor growth. It is shown that the framework in which the convergence of the SQH scheme is proved is applicable for this highly non-linear case. Next, the case of PDE control problems is considered. First a general framework is discussed in which a solution to the corresponding optimal control problem fulfills the PMP conditions. In this case, many theoretical estimates are presented in Theorem 59 and Theorem 64 to prove in particular the essential boundedness of the state and adjoint variables. The steps for the convergence analysis of the SQH scheme are analogous to that of the ODE case and result in Theorem 27 that states the PMP consistency of the solution obtained with the SQH scheme. This framework is applied to different elliptic and parabolic optimal control problems, including linear and bilinear control mechanisms, as well as non-linear state equations. Moreover, the SQH method is discussed for solving a state-constrained optimal control problem in an augmented formulation. In this case, it is shown in Theorem 30 that for increasing the weight of the augmentation term, which penalizes the violation of the state constraint, the measure of this state constraint violation by the corresponding solution converges to zero. Furthermore, an optimal control problem with a non-smooth L\(^1\)-tracking term and a non-smooth state equation is investigated. For this purpose, an adjoint equation is defined and the SQH method is used to solve the corresponding optimal control problem. The final part of this thesis is devoted to a class of FP models related to specific stochastic processes. The discussion starts with a focus on random walks where also jumps are included. This framework allows a derivation of a discrete FP model corresponding to a continuous FP model with jumps and boundary conditions ranging from absorbing to totally reflecting. This discussion allows the consideration of the drift-control resulting from an anisotropic probability of the steps of the random walk. Thereafter, in the PMP framework, two drift-diffusion processes and the corresponding FP models with two different control strategies for an optimal control problem with an expectation functional are considered. In the first strategy, the controls depend on time and in the second one, the controls depend on space and time. In both cases a solution to the corresponding optimal control problem is characterized with the PMP conditions, stated in Theorem 48 and Theorem 49. The well-posedness of the SQH scheme is shown in both cases and further conditions are discussed that ensure the convergence of the SQH scheme to a PMP consistent solution. The case of a space and time dependent control strategy results in a special structure of the corresponding PMP conditions that is exploited in another solution method, the so-called direct Hamiltonian (DH) method.}, subject = {Optimale Kontrolle}, language = {en} } @phdthesis{Kaymak2019, author = {Kaymak, Irem}, title = {Identification of metabolic liabilities in 3D models of cancer}, doi = {10.25972/OPUS-18154}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181544}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Inefficient vascularisation of solid tumours leads to the formation of oxygen and nutrient gradients. In order to mimic this specific feature of the tumour microenvironment, a multicellular tumour spheroid (SPH) culture system was used. These experiments were implemented in p53 isogenic colon cancer cell lines (HCT116 p53 +/+ and HCT116 p53-/-) since Tp53 has important regulatory functions in tumour metabolism. First, the characteristics of the cells cultured as monolayers and as spheroids were investigated by using RNA sequencing and metabolomics to compare gene expression and metabolic features of cells grown in different conditions. This analysis showed that certain features of gene expression found in tumours are also present in spheroids but not in monolayer cultures, including reduced proliferation and induction of hypoxia related genes. Moreover, comparison between the different genotypes revealed that the expression of genes involved in cholesterol homeostasis is induced in p53 deficient cells compared to p53 wild type cells and this difference was only detected in spheroids and tumour samples but not in monolayer cultures. In addition, it was established that loss of p53 leads to the induction of enzymes of the mevalonate pathway via activation of the transcription factor SREBP2, resulting in a metabolic rewiring that supports the generation of ubiquinone (coenzyme Q10). An adequate supply of ubiquinone was essential to support mitochondrial electron transport and pyrimidine biosynthesis in p53 deficient cancer cells under conditions of metabolic stress. Moreover, inhibition of the mevalonate pathway using statins selectively induced oxidative stress and apoptosis in p53 deficient colon cancer cells exposed to oxygen and nutrient deprivation. This was caused by ubiquinone being required for electron transfer by dihydroorotate dehydrogenase, an essential enzyme of the pyrimidine nucleotide biosynthesis pathway. Supplementation with exogenous nucleosides relieved the demand for electron transfer and restored viability of p53 deficient cancer cells under metabolic stress. Moreover, the mevalonate pathway was also essential for the synthesis of ubiquinone for nucleotide biosynthesis to support growth of intestinal tumour organoids. Together, these findings highlight the importance of the mevalonate pathway in cancer cells and provide molecular evidence for an enhanced sensitivity towards the inhibition of mitochondrial electron transfer in tumour-like metabolic environments.}, subject = {Tumor}, language = {en} } @article{WernerOrdonezSanchezBautistaetal.2019, author = {Werner, Rudolf A. and Ordonez, Alvaro A. and Sanchez-Bautista, Julian and Marcus, Charles and Lapa, Constantin and Rowe, Steven P. and Pomper, Martin G. and Leal, Jeffrey P. and Lodge, Martin A. and Javadi, Mehrbod S. and Jain, Sanjay K. and Higuchi, Takahiro}, title = {Novel functional renal PET imaging with 18F-FDS in human subjects}, series = {Clinical Nuclear Medicine}, volume = {44}, journal = {Clinical Nuclear Medicine}, number = {5}, issn = {0363-9762}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-174634}, pages = {410-411}, year = {2019}, abstract = {The novel PET probe 2-deoxy-2-18F-fluoro-D-sorbitol (18F-FDS) has demonstrated favorable renal kinetics in animals. We aimed to elucidate its imaging properties in two human volunteers. 18F-FDS was produced by a simple one-step reduction from 18F-FDG. On dynamic renal PET, the cortex was delineated and activity gradually transited in the parenchyma, followed by radiotracer excretion. No adverse effects were reported. Given the higher spatiotemporal resolution of PET relative to conventional scintigraphy, 18F-FDS PET offers a more thorough evaluation of human renal kinetics. Due to its simple production from 18F-FDG, 18F-FDS is virtually available at any PET facility with radiochemistry infrastructure.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @phdthesis{Peng2019, author = {Peng, Dongliang}, title = {An Optimization-Based Approach for Continuous Map Generalization}, edition = {1. Auflage}, publisher = {W{\"u}rzburg University Press}, address = {W{\"u}rzburg}, isbn = {978-3-95826-104-4}, doi = {10.25972/WUP-978-3-95826-105-1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-174427}, school = {W{\"u}rzburg University Press}, pages = {xv, 132}, year = {2019}, abstract = {Maps are the main tool to represent geographical information. Geographical information is usually scale-dependent, so users need to have access to maps at different scales. In our digital age, the access is realized by zooming. As discrete changes during the zooming tend to distract users, smooth changes are preferred. This is why some digital maps are trying to make the zooming as continuous as they can. The process of producing maps at different scales with smooth changes is called continuous map generalization. In order to produce maps of high quality, cartographers often take into account additional requirements. These requirements are transferred to models in map generalization. Optimization for map generalization is important not only because it finds optimal solutions in the sense of the models, but also because it helps us to evaluate the quality of the models. Optimization, however, becomes more delicate when we deal with continuous map generalization. In this area, there are requirements not only for a specific map but also for relations between maps at difference scales. This thesis is about continuous map generalization based on optimization. First, we show the background of our research topics. Second, we find optimal sequences for aggregating land-cover areas. We compare the A\$^{\!\star}\$\xspace algorithm and integer linear programming in completing this task. Third, we continuously generalize county boundaries to provincial boundaries based on compatible triangulations. We morph between the two sets of boundaries, using dynamic programming to compute the correspondence. Fourth, we continuously generalize buildings to built-up areas by aggregating and growing. In this work, we group buildings with the help of a minimum spanning tree. Fifth, we define vertex trajectories that allow us to morph between polylines. We require that both the angles and the edge lengths change linearly over time. As it is impossible to fulfill all of these requirements simultaneously, we mediate between them using least-squares adjustment. Sixth, we discuss the performance of some commonly used data structures for a specific spatial problem. Seventh, we conclude this thesis and present open problems.}, subject = {Generalisierung }, language = {en} } @phdthesis{Grimm2019, author = {Grimm, Johannes}, title = {Autocrine and paracrine effects of BRAF inhibitor induced senescence in melanoma}, doi = {10.25972/OPUS-18116}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181161}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The FDA approval of targeted therapy with BRAFV600E inhibitors like vemurafenib and dabrafenib in 2011 has been the first major breakthrough in the treatment of metastatic melanoma since almost three decades. Despite increased progression free survival and elevated overall survival rates, complete responses are scarce due to resistance development approximately six months after the initial drug treatment. It was previously shown in our group that melanoma cells under vemurafenib pressure in vitro and in vivo exhibit features of drug-induced senescence. It is known that some cell types, which undergo this cell cycle arrest, develop a so-called senescence associated secretome and it has been reported that melanoma cell lines also upregulate the expression of different factors after senescence induction. This work describes the effect of the vemurafenib-induced secretome on cells. Conditioned supernatants of vemurafenib-treated cells increased the viability of naive fibroblast and melanoma cell lines. RNA analysis of donor melanoma cells revealed elevated transcriptional levels of FGF1, MMP2 and CCL2 in the majority of tested cell lines under vemurafenib pressure, and I could confirm the secretion of functional proteins. Similar observations were also done after MEK inhibition as well as in a combined BRAF and MEK inhibitor treatment situation. Interestingly, the transcription of other FGF ligands (FGF7, FGF17) was also elevated after MEK/ERK1/2 inhibition. As FGF receptors are therapeutically relevant, I focused on the analysis of FGFR-dependent processes in response to BRAF inhibition. Recombinant FGF1 increased the survival rate of melanoma cells under vemurafenib pressure, while inhibition of the FGFR pathway diminished the viability of melanoma cells in combination with vemurafenib and blocked the stimulatory effect of vemurafenib conditioned medium. The BRAF inhibitor induced secretome is regulated by active PI3K/AKT signaling, and the joint inhibition of mTor and BRAFV600E led to decreased senescence induction and to a diminished induction of the secretome-associated genes. In parallel, combined inhibition of MEK and PI3K also drastically decreased mRNA levels of the relevant secretome components back to basal levels. In summary, I could demonstrate that BRAF inhibitor treated melanoma cell lines acquire a specific PI3K/AKT dependent secretome, which is characterized by FGF1, CCL2 and MMP2. This secretome is able to stimulate other cells such as naive melanoma cells and fibroblasts and contributes to a better survival under drug pressure. These data are therapeutically highly relevant, as they imply the usage of novel drug combinations, especially specific FGFR inhibitors, with BRAF inhibitors in the clinic.}, subject = {Inhibitor}, language = {en} } @phdthesis{Halbig2019, author = {Halbig, Benedikt}, title = {Surface Raman Spectroscopy on Ordered Metal Adsorbates on Semiconductor Substrates and Thin Intermetallic Films}, doi = {10.25972/OPUS-18138}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181385}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Surface systems attract great scientific attention due to novel and exotic properties. The atomically structured surfaces lead to a reduced dimensionality which alters electronic correlations, vibrational properties, and their impact on each other. The emerging physical phenomena are not observed for related bulk materials. In this thesis, ordered (sub)monolayers of metal atoms (Au and Sn) on semiconductor substrates (Si(111) and Ge(111)) and ultrathin intermetallic films (CePt5 and LaPt5) on metal substrate (Pt(111)) are investigated by polarized in situ surface Raman spectroscopy. The surface Raman spectra exhibit features of specific elementary excitations like surface phonons and electronic excitations, which are suitable to gain fundamental insights into the surface systems. The Au-induced surface reconstructions (5x2) and (r3xr3) constitute quasi-one- and two-dimensional Au structures on the Si(111) substrate, respectively. The new reconstruction-related Raman peaks are analyzed with respect to their polarization and temperature behavior. The Raman results are combined with firstprinciples calculations to decide between different proposed structural models. The Au-(5x2)/Si(111) reconstruction is best described by the model of Kwon and Kang, while for Au-(r3xr3)/Si(111) the conjugate honeycomb-chained-trimer model is favored. The Sn-induced reconstructions with 1/3 monolayer on Ge(111) and Si(111) are investigated to reveal their extraordinary temperature behavior. Specific surface phonon modes are identified that are predicted within the dynamical fluctuation model. Contrary to Sn/Si(111), the corresponding vibrational mode of Sn/Ge(111) exhibits a nearly harmonic character. The reversible structural phase transition of Sn/Ge(111) from (r3xr3) to (3x3) is observed, while no phase transition is apparent for Sn/Si(111). Moreover, Raman spectra of the closely related systems Sn-(2r3x2r3)/Si(111) and thin films of a-Sn as well as the clean semiconductor surfaces Si(111)-(7x7) and Ge(111)-c(2x8) are evaluated and compared. The CePt5/Pt(111) system hosts 4f electrons whose energy levels are modified by the crystal field and are relevant for a description of the observed Kondo physics. In contrast, isostructural LaPt5/Pt(111) has no 4f electrons. For CePt5/Pt(111), distinct Raman features due to electronic Raman scattering can be unambiguously related to transitions between the crystal-field states which are depth-dependent. This assignment is supported by comparison to LaPt5/Pt(111) and group theoretical considerations. Furthermore, the vibrational properties of CePt5 and LaPt5 reveal interesting similarities but also striking differences like an unusual temperature shift of a vibration mode of CePt5, which is related to the influence of 4f electrons.}, subject = {Raman-Spektroskopie}, language = {en} } @phdthesis{Walter2019, author = {Walter, J{\"u}rgen Christian}, title = {Automation in Software Performance Engineering Based on a Declarative Specification of Concerns}, doi = {10.25972/OPUS-18090}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-180904}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Software performance is of particular relevance to software system design, operation, and evolution because it has a significant impact on key business indicators. During the life-cycle of a software system, its implementation, configuration, and deployment are subject to multiple changes that may affect the end-to-end performance characteristics. Consequently, performance analysts continually need to provide answers to and act based on performance-relevant concerns. To ensure a desired level of performance, software performance engineering provides a plethora of methods, techniques, and tools for measuring, modeling, and evaluating performance properties of software systems. However, the answering of performance concerns is subject to a significant semantic gap between the level on which performance concerns are formulated and the technical level on which performance evaluations are actually conducted. Performance evaluation approaches come with different strengths and limitations concerning, for example, accuracy, time-to-result, or system overhead. For the involved stakeholders, it can be an elaborate process to reasonably select, parameterize and correctly apply performance evaluation approaches, and to filter and interpret the obtained results. An additional challenge is that available performance evaluation artifacts may change over time, which requires to switch between different measurement-based and model-based performance evaluation approaches during the system evolution. At model-based analysis, the effort involved in creating performance models can also outweigh their benefits. To overcome the deficiencies and enable an automatic and holistic evaluation of performance throughout the software engineering life-cycle requires an approach that: (i) integrates multiple types of performance concerns and evaluation approaches, (ii) automates performance model creation, and (iii) automatically selects an evaluation methodology tailored to a specific scenario. This thesis presents a declarative approach —called Declarative Performance Engineering (DPE)— to automate performance evaluation based on a humanreadable specification of performance-related concerns. To this end, we separate the definition of performance concerns from their solution. The primary scientific contributions presented in this thesis are: A declarative language to express performance-related concerns and a corresponding processing framework: We provide a language to specify performance concerns independent of a concrete performance evaluation approach. Besides the specification of functional aspects, the language allows to include non-functional tradeoffs optionally. To answer these concerns, we provide a framework architecture and a corresponding reference implementation to process performance concerns automatically. It allows to integrate arbitrary performance evaluation approaches and is accompanied by reference implementations for model-based and measurement-based performance evaluation. Automated creation of architectural performance models from execution traces: The creation of performance models can be subject to significant efforts outweighing the benefits of model-based performance evaluation. We provide a model extraction framework that creates architectural performance models based on execution traces, provided by monitoring tools.The framework separates the derivation of generic information from model creation routines. To derive generic information, the framework combines state-of-the-art extraction and estimation techniques. We isolate object creation routines specified in a generic model builder interface based on concepts present in multiple performance-annotated architectural modeling formalisms. To create model extraction for a novel performance modeling formalism, developers only need to write object creation routines instead of creating model extraction software from scratch when reusing the generic framework. Automated and extensible decision support for performance evaluation approaches: We present a methodology and tooling for the automated selection of a performance evaluation approach tailored to the user concerns and application scenario. To this end, we propose to decouple the complexity of selecting a performance evaluation approach for a given scenario by providing solution approach capability models and a generic decision engine. The proposed capability meta-model enables to describe functional and non-functional capabilities of performance evaluation approaches and tools at different granularities. In contrast to existing tree-based decision support mechanisms, the decoupling approach allows to easily update characteristics of solution approaches as well as appending new rating criteria and thereby stay abreast of evolution in performance evaluation tooling and system technologies. Time-to-result estimation for model-based performance prediction: The time required to execute a model-based analysis plays an important role in different decision processes. For example, evaluation scenarios might require the prediction results to be available in a limited period of time such that the system can be adapted in time to ensure the desired quality of service. We propose a method to estimate the time-to-result for modelbased performance prediction based on model characteristics and analysis parametrization. We learn a prediction model using performancerelevant features thatwe determined using statistical tests. We implement the approach and demonstrate its practicability by applying it to analyze a simulation-based multi-step performance evaluation approach for a representative architectural performance modeling formalism. We validate each of the contributions based on representative case studies. The evaluation of automatic performance model extraction for two case study systems shows that the resulting models can accurately predict the performance behavior. Prediction accuracy errors are below 3\% for resource utilization and mostly less than 20\% for service response time. The separate evaluation of the reusability shows that the presented approach lowers the implementation efforts for automated model extraction tools by up to 91\%. Based on two case studies applying measurement-based and model-based performance evaluation techniques, we demonstrate the suitability of the declarative performance engineering framework to answer multiple kinds of performance concerns customized to non-functional goals. Subsequently, we discuss reduced efforts in applying performance analyses using the integrated and automated declarative approach. Also, the evaluation of the declarative framework reviews benefits and savings integrating performance evaluation approaches into the declarative performance engineering framework. We demonstrate the applicability of the decision framework for performance evaluation approaches by applying it to depict existing decision trees. Then, we show how we can quickly adapt to the evolution of performance evaluation methods which is challenging for static tree-based decision support systems. At this, we show how to cope with the evolution of functional and non-functional capabilities of performance evaluation software and explain how to integrate new approaches. Finally, we evaluate the accuracy of the time-to-result estimation for a set of machinelearning algorithms and different training datasets. The predictions exhibit a mean percentage error below 20\%, which can be further improved by including performance evaluations of the considered model into the training data. The presented contributions represent a significant step towards an integrated performance engineering process that combines the strengths of model-based and measurement-based performance evaluation. The proposed performance concern language in conjunction with the processing framework significantly reduces the complexity of applying performance evaluations for all stakeholders. Thereby it enables performance awareness throughout the software engineering life-cycle. The proposed performance concern language removes the semantic gap between the level on which performance concerns are formulated and the technical level on which performance evaluations are actually conducted by the user.}, subject = {Software}, language = {en} } @phdthesis{Letschert2019, author = {Letschert, Sebastian}, title = {Quantitative Analysis of Membrane Components using Super-Resolution Microscopy}, doi = {10.25972/OPUS-16213}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-162139}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The plasma membrane is one of the most thoroughly studied and at the same time most complex, diverse, and least understood cellular structures. Its function is determined by the molecular composition as well as the spatial arrangement of its components. Even after decades of extensive membrane research and the proposal of dozens of models and theories, the structural organization of plasma membranes remains largely unknown. Modern imaging tools such as super-resolution fluorescence microscopy are one of the most efficient techniques in life sciences and are widely used to study the spatial arrangement and quantitative behavior of biomolecules in fixed and living cells. In this work, direct stochastic optical reconstruction microscopy (dSTORM) was used to investigate the structural distribution of mem-brane components with virtually molecular resolution. Key issues are different preparation and staining strategies for membrane imaging as well as localization-based quantitative analyses of membrane molecules. An essential precondition for the spatial and quantitative analysis of membrane components is the prevention of photoswitching artifacts in reconstructed localization microscopy images. Therefore, the impact of irradiation intensity, label density and photoswitching behavior on the distribution of plasma membrane and mitochondrial membrane proteins in dSTORM images was investigated. It is demonstrated that the combination of densely labeled plasma membranes and inappropriate photoswitching rates induces artificial membrane clusters. Moreover, inhomogeneous localization distributions induced by projections of three-dimensional membrane structures such as microvilli and vesicles are prone to generate artifacts in images of biological membranes. Alternative imaging techniques and ways to prevent artifacts in single-molecule localization microscopy are presented and extensively discussed. Another central topic addresses the spatial organization of glycosylated components covering the cell membrane. It is shown that a bioorthogonal chemical reporter system consisting of modified monosaccharide precursors and organic fluorophores can be used for specific labeling of membrane-associated glycoproteins and -lipids. The distribution of glycans was visualized by dSTORM showing a homogeneous molecule distribution on different mammalian cell lines without the presence of clusters. An absolute number of around five million glycans per cell was estimated and the results show that the combination of metabolic labeling, click chemistry, and single-molecule localization microscopy can be efficiently used to study cell surface glycoconjugates. In a third project, dSTORM was performed to investigate low-expressing receptors on cancer cells which can act as targets in personalized immunotherapy. Primary multiple myeloma cells derived from the bone marrow of several patients were analyzed for CD19 expression as potential target for chimeric antigen receptor (CAR)-modified T cells. Depending on the patient, 60-1,600 CD19 molecules per cell were quantified and functional in vitro tests demonstrate that the threshold for CD19 CAR T recognition is below 100 CD19 molecules per target cell. Results are compared with flow cytometry data, and the important roles of efficient labeling and appropriate control experiments are discussed.}, subject = {Fluoreszenzmikroskopie}, language = {en} } @phdthesis{Endres2019, author = {Endres, Ralph Julian}, title = {Networks of fear: Functional connectivity of the amygdala, the insula and the anterior cingulate cortex in two subtypes of specific phobia}, doi = {10.25972/OPUS-18095}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-180950}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Neuroimaging research has highlighted the relevance of well-balanced functional brain interactions as an essential basis for efficient emotion regulation. In contrast, abnormal coupling of fear-processing regions such as the amygdala, the anterior cingulate cortex (ACC) and the insula could be an important feature of anxiety disorders. Although activity alterations of these regions have been frequently reported in specific phobia, little is known about their functional interactions during phobogenic stimulus processing. To explore these interrelationships in two subtypes of specific phobia - i.e., the blood-injection-injury subtype and the animal subtype - functional connectivity (FC) was analyzed in three fMRI studies. Two studies examined fear processing in a dental phobia group (DP), a snake phobia group (SP) and a healthy control group (HC) during visual phobogenic stimuli presentation while a third study investigated differences between auditory and visual stimuli presentation in DP and HC. Due to a priori hypotheses of impaired interactions between the amygdala, the ACC and the insula, a first analysis was conducted to explore the FC within these three regions of interest. Based on emerging evidence of functionally diverse subregions, the ACC was further divided into a subgenual, pregenual and dorsal ACC and the insula was divided into a ventral-anterior, dorsal-anterior and posterior region. Additionally, an exploratory seed-to-voxel analysis using the amygdala, ACC and insula as seeds was conducted to scan for connectivity patterns across the whole brain. The analyses revealed a negative connectivity of the ACC and the amygdala during phobogenic stimulus processing in controls. This connectivity was predominantly driven by the affective ACC subdivision. By contrast, SP was characterized by an increased mean FC between the examined regions. Interestingly, this phenomenon was specific for auditory, but not visual symptom provocation in DP. During visual stimulus presentation, however, DP exhibited further FC alterations of the ACC and the insula with pre- and orbitofrontal regions. These findings mark the importance of balanced interactions between fear-processing regions in specific phobia, particularly of the inhibitory connectivity between the ACC and the amygdala. Theoretically, this is assumed to reflect top-down inhibition by the ACC during emotion regulation. The findings support the suggestion that SP particularly is characterized by excitatory, or missing inhibitory, (para-) limbic connectivity, reflecting an overshooting fear response based on evolutionary conserved autonomic bottom-up pathways. Some of these characteristics applied to DP as well but only under the auditory stimulation, pointing to stimulus dependency. DP was further marked by altered pre- and orbitofrontal coupling with the ACC and the insula which might represent disturbances of superordinate cognitive control on basal emotion processes. These observations strengthen the assumption that DP is predominantly based on evaluation-based fear responses. In conclusion, the connectivity patterns found may depict an intermediate phenotype that possibly confers risks for inappropriate phobic fear responses. The findings presented could also be of clinical interest. Particularly the ACC - amygdala circuit may be used as a predictive biomarker for treatment response or as a promising target for neuroscience-focused augmentation strategies as neurofeedback or repetitive transcranial magnetic stimulation.}, subject = {Kernspintomografie}, language = {en} } @phdthesis{Zilker2019, author = {Zilker, Markus}, title = {The stability of finished pharmaceutical products and drug substances beyond their labeled expiry dates}, doi = {10.25972/OPUS-18069}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-180695}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Upon approval of a drug, the stability of the API and the FPP has to be studied intensively because it determines the shelf-life. If a drug is found to be stable, the expiry date is arbitrary set to five years at the maximum, if a drug tends to undergo degradation, the expiry date is set shorter. The drug product must comply with predefined specifications in accordance with the ICH guidelines Q6A and Q6B during its entire market life. The content of the active substance is required to be within a specification of 95-105\% of its labeled claim until expiry corresponding to the ICH guideline Q1A(R2). However, there is little or scattered literature information addressing the stability of drug products beyond their expiry dates. The objective of this thesis was to study and assess the long-term stability of a collection involving numerous pure drug substances and ampoules manufactured in the 20th century. The content and the impurity profile were examined by means of appropriate analytical methods, mainly using liquid chromatography. The results were compared to data being available in the literature. Assessing the stability regarding the dosage form and the affiliation of the drug class was conducted. The experimental studies comprise the examination of 50 drug substances manufactured 20-30 years ago and 14 long expired ampoules which were older than 40 years in the time of analysis, exceeding many times the maximum shelf life of five years. For investigation of the solid drug substances, pharmacopoeial methods were applied as far as possible. Indeed, results of the study showed that 44 tested substances still complied with the specification of the Ph. Eur. with regard to the content and impurity profile, even after more than two decades of storage. For analysis of the injection solutions, HPLC-UV and HPLC-ESI/MS techniques were applied, commonly based on liquid chromatography methods of the Ph. Eur. for determination of related substances. Each method was further validated for its application to ensure accurate API quantification corresponding to ICH Q2(R1). Quite a few ampoules were identified to show surprisingly high stability. In spite of their age of 53-72 years, APIs such as caffeine, etilefrine, synephrine, metamizole sodium, furosemide, and sodium salicylate complied with the specified content that is valid nowadays, respectively. Nevertheless, typical degradation reaction, e.g. hydrolysis, oxidation, or isomerization, was observed in all remaining ampoules. Various degrees of hydrolysis were revealed for scopolamine, procaine, and adenosine triphosphate, the contents were decreased to 71\%, 70\%, and 15\% of the declared concentrations, respectively. In the epinephrine and dipyridamole ampoules, oxidative degradation has been occurred, finding respective API contents of more or less 70\%. For dihydroergotamine, excessive decomposition by epimerization was observed, resulting in an API content of 21\% and degradation by isomerization was found in lobeline, still containing 64\% of the labeled claim. In conclusion, supported by the data of the present studies and the literature, defining and authorizing a longer shelf-life may be applicable to numerous pharmaceuticals which should be considered by pharmaceutical manufacturers and regulatory authorities, if justified based on stability studies. A general extension of the shelf-lives of drug products and the abolishment or extension of the maximum shelf-life limit of five years would prevent disposing of still potent medications and save a lot of money to the entire health care system.}, subject = {Stabilit{\"a}t}, language = {en} } @phdthesis{Saleh2019, author = {Saleh, Ahmed}, title = {The emerging role of stress speckle tracking in viability world}, doi = {10.25972/OPUS-18053}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-180536}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Introduction: Speckle-tracking echocardiography has recently emerged as a quantitative ultrasound technique for accurately evaluating myocardial function by analyzing the motion of speckles identified. Speckle-tracking obtained under stress may offer an opportunity to improve the detection of dynamic regional abnormalities and myocardial viability. Objective: To evaluate stress speckle tracking as tool to detect myocardial viability in comparison to cardiac MRI in post-STEMI patients. Methods: 49 patients were prospectively enrolled in our 18-month's study. Dobutamin stress echocardiography was performed 4 days post-infarction accompanied with automated functional imaging (Speckle tracking) analysis of left ventricle during rest and then during low dose stress. All patients underwent a follow up stress echocardiography at 6 weeks with speckle tracking analysis. Cardiac MRI took place concomitantly at 4 days post-infarction and 6 weeks. We carried out an assessment of re-admission with acute coronary syndrome (ACS) after one year of enrollment. Results: Investigating strain rate obtained with stress speckle tracking after revascularization predicted the extent of myocardial scar, determined by contrast-enhanced magnetic resonance imaging. A good correlation was found between the global strain and total infarct size (R 0.75, p< 0.001). Furthermore, a clear inverse relationship was found between the segmental strain and the transmural extent of infarction in each segment. (R -0.69, p<0.01). Meanwhile it provided 81.82\% sensitivity and 82.6\% specificity to detect transmural from non-transmural infarction at a cut-off value of -10.15. Global stress strain rate showed 80\% sensitivity and 77.5\% specificity at a cut-off value of -9.1 to predict hospital re-admission with ACS. A cut-off value of -8.4 had shown a 69.23\% sensitivity and 73.5\% specificity to predict the re-admission related to other cardiac symptoms. Conclusion: Strain rate obtained from speckle tracking during stress is a novel method of detecting myocardial viability after STEMI .Moreover it carries a promising role in post-myocardial infarction risk stratification with a reasonable prediction of reversible cardiac-related hospital re-admission.}, language = {en} } @phdthesis{Lorson2019, author = {Lorson, Thomas}, title = {Novel Poly(2-oxazoline) Based Bioinks}, doi = {10.25972/OPUS-18051}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-180514}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Motivated by the great potential which is offered by the combination of additive manufacturing and tissue engineering, a novel polymeric bioink platform based on poly(2 oxazoline)s was developed which might help to further advance the young and upcoming field of biofabrication. In the present thesis, the synthesis as well as the characteristics of several diblock copolymers consisting of POx and POzi have been investigated with a special focus on their suitability as bioinks. In general, the copolymerization of 2-oxazolines and 2-oxazines bearing different alkyl side chains was demonstrated to yield polymers in good agreement with the degree of polymerization aimed for and moderate to low dispersities. For every diblock copolymer synthesized during the present study, a more or less pronounced dependency of the dynamic viscosity on temperature could be demonstrated. Diblock copolymers comprising a hydrophilic PMeOx block and a thermoresponsive PnPrOzi block showed temperature induced gelation above a degree of polymerization of 50 and a polymer concentration of 20 wt\%. Such a behavior has never been described before for copolymers solely consisting of poly(cyclic imino ether)s. Physically cross linked hydrogels based on POx b POzi copolymers exhibit reverse thermal gelation properties like described for solutions of PNiPAAm and Pluronic F127. However, by applying SANS, DLS, and SLS it could be demonstrated that the underlying gel formation mechanism is different for POx b POzi based hydrogels. It appears that polymersomes with low polydispersity are formed already at very low polymer concentrations of 6 mg/L. Increasing the polymer concentration resulted in the formation of a bicontinuous sponge like structure which might be formed due to the merger of several vesicles. For longer polymer chains a phase transition into a gyroid structure was postulated and corresponds well with the observed rheological data. Stable hydrogels with an unusually high mechanical strength (G' ~ 4 kPa) have been formed above TGel which could be adjusted over a range of 20 °C by changing the degree of polymerization if maintaining the symmetric polymer architecture. Variations of the chain ends revealed only a minor influence on TGel whereas the influence of the solvent should not be neglected as shown by a comparison of cell culture medium and MilliQ water. Rotationally as well as oscillatory rheological measurements revealed a high suitability for printing as POx b POzi based hydrogels exhibit strong shear thinning behavior in combination with outstanding recovery properties after high shear stress. Cell viability assays (WST-1) of PMeOx b PnPrOzi copolymers against NIH 3T3 fibroblasts and HaCat cells indicated that the polymers were well tolerated by the cells as no dose-dependent cytotoxicity could be observed after 24 h at non-gelling concentrations up to 100 g/L. In summary, copolymers consisting of POx and POzi significantly increased the accessible range of properties of POx based materials. In particular thermogelation of aqueous solutions of diblock copolymers comprising PMeOx and PnPrOzi was never described before for any copolymer consisting solely of POx or POzi. In combination with other characteristics, e.g. very good cytocompatibility at high polymer concentrations and comparably high mechanical strength, the formed hydrogels could be successfully used for 3D bioprinting. Although the results appear promising and the developed hydrogel is a serious bioink candidate, competition is tough and it remains an open question which system or systems will be used in the future.}, subject = {Polymere}, language = {en} } @unpublished{StennettBissingerGriesbecketal.2019, author = {Stennett, Tom E. and Bissinger, Philipp and Griesbeck, Stefanie and Ullrich, Stefan and Krummenacher, Ivo and Auth, Michael and Sperlich, Andreas and Stolte, Matthias and Radacki, Krzysztof and Yao, Chang-Jiang and W{\"u}rthner, Frank and Steffen, Andreas and Marder, Todd B. and Braunschweig, Holger}, title = {Near-Infrared Quadrupolar Chromophores Combining Three-Coordinate Boron-Based Superdonor and Superacceptor Units}, series = {Angewandte Chemie, International Edition}, journal = {Angewandte Chemie, International Edition}, doi = {10.1002/anie.201900889}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-180391}, year = {2019}, abstract = {In this work, two new quadrupolar A-π-D-π-A chromophores have been prepared featuring a strongly electron- donating diborene core and strongly electron-accepting dimesitylboryl F(BMes2) and bis(2,4,6-tris(trifluoromethyl)phenyl)boryl (BMes2) end groups. Analysis of the compounds by NMR spectroscopy, X-ray crystallography, cyclic voltammetry and UV-vis-NIR absorption and emission spectroscopy indicated that the compounds possess extended conjugated π-systems spanning their B4C8 cores. The combination of exceptionally potent π-donor (diborene) and π- acceptor (diarylboryl) groups, both based on trigonal boron, leads to very small HOMO-LUMO gaps, resulting in strong absorption in the near-IR region with maxima in THF at 840 and 1092 nm, respectively, and very high extinction coefficients of ca. 120,000 M-1cm-1. Both molecules also display weak near-IR fluorescence with small Stokes shifts.}, language = {en} } @phdthesis{Riese2019, author = {Riese, Stefan}, title = {Photophysics and Spin Chemistry of Donor-Acceptor substituted Dipyrrinato-Metal-Complexes}, doi = {10.25972/OPUS-18022}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-180228}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {In this thesis, the photophysics and spin chemistry of donor-photosensitizer-acceptor triads were investigated. While all investigated triads comprised a TAA as an electron donor and a NDI as an electron acceptor, the central photosensitizers (PS) were different chromophores based on the dipyrrin-motif. The purity and identity of all target compounds could be confirmed by NMR spectroscopy, mass spectrometry and elemental analysis. The first part of the work dealt with dipyrrinato-complexes of cyclometalated heavy transition metals. The successful synthesis of novel triads based on Ir(III), Pt(II) and Pd(II) was presented. The optical and electrochemical properties indicated charge separation (CS), which was confirmed by transient absorption (TA) spectroscopy. TA-spectroscopy also revealed that the process of CS is significantly slower and less efficient for the triads based on Pt(II) and Pd(II) than for the analogous Ir(III) triads. This is mostly due to a much more convoluted reaction pathway, comprising several intermediate states before the formation of the final charge separated state (CSS2). On the other hand, CSS2 exhibits long lifetimes which are dependent on the central metal ion. While the Ir(III) triads show lifetimes of about 0.5 µs in MeCN, the Pt(II) and Pd(II) analogues show lifetimes of 1.5 µs. The magnetic field effect on the charge recombination (CR) kinetics of CSS2 was investigated by magnetic field dependent ns-TA spectroscopy and could be rationalized based on a classical kinetic scheme comprising only one magnetic field dependent rate constant k±. The behavior of k± shows a clear separation of the coherent and incoherent spin interconversion mechanisms. While the coherent spin evolution is due to the isotropic hyperfine coupling with the magnetic nuclei of the radical centers, the incoherent spin relaxation is due to a rotational modulation of the anisotropic hyperfine coupling tensor and is strongly dependent on the viscosity of the solvent. This dependence could be used to measure the nanoviscosity of the oligomeric solvent pTHF, which was found to be distinctly different from its macroviscosity. The second part of the work dealt with bisdipyrrinato complexes and their bridged porphodimethenato (PDM) analogues. Initially, the suitability of the different chromophores for the use as PS in donor-acceptor substituted triads was tested by a systematic investigation of their steady state and transient properties. While the PDM-complex of Zn(II) and Pd(II) exhibited promising characteristics such as a high exited state lifetime and relatively intense emission, the purely organic parent PDM and the non-bridged bisdipyrrinato-Pd(II) complex were less suitable. The difference between the two Pd(II) complexes could be explained by a structural rearrangement of the non-bridged complex which results in a non-emissive metal centered triplet state with disphenoidal geometry. This rearrangement is prevented by the dimethylmethylene-bridges in the bridged analogue resulting in higher phosphorescence quantum yields and excited state lifetimes. With the exception of the Zn(II)PDM-complex, the synthesis of novel donor acceptor substituted triads could be realized for all desired central chromophores. They were investigated equivalently to the cyclometalated triads described in the first part. The steady state properties indicate a stronger electronic coupling between the subunits due to the lack of unsaturated bridges between the donor and the central chromophore. Photoinduced CS occurs in all investigated triads. Due to the low exited state lifetimes of the central chromophores, CSS is formed less efficiently for the triads based on the unbridged Pd(II)-complex as well as the purely organic PDM. In the triad based on the bridged Pd(II) complex, the CR of CSS2 is faster than its formation resulting in low intermediate concentrations. For its elongated analogue, this is not the case and CSS2 can be observed clearly. Although the spin-chemistry of the triads based on bisdipyrrinato-Pd(II) and porphodimethenato-Pd(II) is less well understood, first interpretations of the magnetic field dependent decay kinetics gave results approximately equivalent to those obtained for the cyclometalated triads. Furthermore, the MFE was shown to be useful for the investigation of the quantum yield of CS and the identity of the observed CSSs. In both parts of this work, the influence of the central photosensitizer on the photophysics and the spin chemistry of the triads could be shown. While the process of CS is directly dependent on the PS, the PS usually is not directly involved in the final CSSs. None the less, it can still indirectly affect the CR and spin chemistry of the CSS since it influences the electronic coupling between donor and acceptor, as well as the geometry of the triads.}, subject = {Charge-transfer-Komplexe}, language = {en} } @phdthesis{Simon2019, author = {Simon, Katja}, title = {Identifying the role of Myb-MuvB in gene expression and proliferation of lung cancer cells}, doi = {10.25972/OPUS-16181}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-161814}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The evolutionary conserved Myb-MuvB (MMB) multiprotein complex is a transcriptional master regulator of mitotic gene expression. The MMB subunits B-MYB, FOXM1 as well as target genes of MMB are often overexpressed in different cancer types. Elevated expression of these genes correlates with an advanced tumor state and a poor prognosis for patients. Furthermore, it has been reported that pathways, which are involved in regulating the mitotic machinery are attractive for a potential treatment of cancers harbouring Ras mutations (Luo et al., 2009). This suggest that the MMB complex could be required for tumorigenesis by mediating overactivity of mitotic genes and that the MMB could be a useful target for lung cancer treatment. However, although MMB has been characterized biochemically, the contribution of MMB to tumorigenesis is largely unknown in particular in vivo. In this thesis, it was demonstrated that the MMB complex is required for lung tumorigenesis in vivo in a mouse model of non small cell lung cancer. Elevated levels of B-MYB, NUSAP1 or CENPF in advanced tumors as opposed to low levels of these proteins levels in grade 1 or 2 tumors support the possible contribution of MMB to lung tumorigenesis and the oncogenic potential of B-MYB.The tumor growth promoting function of B-MYB was illustrated by a lower fraction of KI-67 positive cells in vivo and a significantly high impairment in proliferation after loss of B-Myb in vitro. Defects in cytokinesis and an abnormal cell cycle profile after loss of B-Myb underscore the impact of B-MYB on proliferation of lung cancer cell lines. The incomplete recombination of B-Myb in murine lung tumors and in the tumor derived primary cell lines illustrates the selection pressure against the complete loss of B-Myb and further demonstrats that B-Myb is a tumor-essential gene. In the last part of this thesis, the contribution of MMB to the proliferation of human lung cancer cells was demonstrated by the RNAi-mediated depletion of B-Myb. Detection of elevated B-MYB levels in human adenocarcinoma and a reduced proliferation, cytokinesis defects and abnormal cell cycle profile after loss of B-MYB in human lung cancer cell lines underlines the potential of B-MYB to serve as a clinical marker.}, subject = {Lungenkrebs}, language = {en} } @phdthesis{Heck2019, author = {Heck, Johannes}, title = {Role of cyclase-associated protein 2 in platelet function and description of an inherited macrothrombocytopenia}, doi = {10.25972/OPUS-17996}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-179968}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Cyclase-associated protein (CAP)2 is an evolutionarily highly conserved actin-binding protein implicated in striated muscle development, carcinogenesis, and wound healing in mammals. To date, the presence as well as the putative role(s) of CAP2 in platelets, however, remain unknown. Therefore, mice constitutively lacking CAP2 (Cap2gt/gt mice) were examined for platelet function. These studies confirmed the presence of both mammalian CAP isoforms, CAP1 and CAP2, in platelets. CAP2-deficient platelets were slightly larger than WT controls and displayed increased GPIIbIIIa activation and P-selectin recruitment in response to the (hem)ITAM-specific agonists collagen-related peptide and rhodocytin. However, spreading of CAP2-deficient platelets on a fibrinogen matrix was unaltered. In conclusion, the functionally redundant CAP1 isoform may compensate for the lack of CAP2 in murine platelets. Moreover, the studies presented in this thesis unveiled a severe macrothrombocytopenia that occurred independently of the targeted Cap2 allele and which was preliminarily termed orphan (orph). Crossing of the respective mice to C57BL/6J wild-type animals revealed an autosomal recessive inheritance. Orph mice were anemic and developed splenomegaly as well as BM fibrosis, suggesting a general hematopoietic defect. Strikingly, BM MKs of orph mice demonstrated an aberrant morphology and appeared to release platelets ectopically into the BM cavity, thus pointing to defective thrombopoiesis as cause for the low platelet counts. Orph platelets exhibited marked activation defects and spread poorly on fibrinogen. The unaltered protein content strongly suggested a defective alpha-granule release to account for the observed hyporesponsiveness. In addition, the cytoskeleton of orph platelets was characterized by disorganized microtubules and accumulations of filamentous actin. However, further experiments are required to elucidate the activation defects and cytoskeletal abnormalities in orph platelets. Above all, the gene mutation responsible for the phenotype of orph mice needs to be determined by next-generation sequencing in order to shed light on the underlying genetic and mechanistic cause.}, subject = {Thrombozyt}, language = {en} } @phdthesis{Awad2019, author = {Awad, Eman Da'as}, title = {Modulation of insulin-induced genotoxicity in vitro and genomic damage in gestational diabetes}, doi = {10.25972/OPUS-16186}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-161866}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Diabetes mellitus is a global health problem, where the risk of diabetes increases rapidly due to the lifestyle changes. Patients with type II diabetes have many complications with increased risk of morbidity and mortality. High levels of insulin may lead to DNA oxidation and damage. Several studies proposed that hyperinsulinemia may be an important risk factor for various types of cancer. To investigate insulin signaling pathway inducing oxidative stress and genomic damage, pharmaceutical and natural compounds which can interfere with the insulin pathway including PI3K inhibitors, resveratrol, lovastatin, and RAD-001 were selected due to their beneficial effects against metabolic disorder. Thus, the anti-genotoxic potential of these compounds regarding insulin-mediated oxidative stress were investigated in normal rat kidney cells in vitro. Our compounds showed protective effect against genotoxic damage and significantly decreased reactive oxygen specious after treatment of cells with insulin with different mechanisms of protection between the compounds. Thus, these compounds may be attractive candidates for future support of diabetes mellitus therapy. Next, we explored the link between gestational diabetes mellitus and genomic damage in cells derived from human blood. Moreover, we investigated the influence of estradiol, progesterone, adrenaline and triiodothyronine on insulin-induced genomic damage in vitro. First, we studied the effect of these hormones in human promyelocytic leukemia cells and next ex vivo with non-stimulated and stimulated peripheral blood mononuclear cells. In parallel, we also measured the basal genomic damage using three conditions (whole blood, non-stimulated and stimulated peripheral blood mononuclear cells) in a small patient study including non-pregnant controls with/without hormonal contraceptives, with a subgroup of obese women, pregnant women, and gestational diabetes affected women. A second-time point after delivery was also applied for analysis of the blood samples. Our results showed that GDM subjects and obese individuals exhibited higher basal DNA damage compared to lower weight nonpregnant or healthy pregnant women in stimulated peripheral blood mononuclear cells in both comet and micronucleus assays. On the other hand, the DNA damage in GDM women had decreased at two months after birth. Moreover, the applied hormones also showed an influence in vitro in the enhancement of the genomic damage in cells of the control and pregnant groups but this damage did not exceed the damage which existed in obese and gestational diabetes mellitus patients with high level of genomic damage. In conclusion, insulin can induce genomic damage in cultured cells, which can be modulated by pharmaceutical and naturals substances. This may be for future use in the protection of diabetic patients, who suffer from hyperinsulinemia during certain disease stages. A particular form of diabetes, GDM, was shown to lead to elevated DNA damage in affected women, which is reduced again after delivery. Cells of affected women do not show an enhanced, but rather a reduced sensitivity for further DNA damage induction by hormonal treatment in vitro. A potential reason may be an existence of a maximally inducible damage by hormonal influences.}, subject = {Gestationsdiabetes}, language = {en} } @unpublished{WernerBundschuhBundschuhetal.2019, author = {Werner, Rudolf A. and Bundschuh, Ralph A. and Bundschuh, Lena and Fanti, Stefano and Javadi, Mehrbod S. and Higuchi, Takahiro and Weich, A. and Pienta, Kenneth J. and Buck, Andreas K. and Pomper, Martin G. and Gorin, Michael A. and Herrmann, Ken and Lapa, Constantin and Rowe, Steven P.}, title = {Novel Structured Reporting Systems for Theranostic Radiotracers}, series = {Journal of Nuclear Medicine}, journal = {Journal of Nuclear Medicine}, issn = {0161-5505}, doi = {10.2967/jnumed.118.223537}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-174629}, year = {2019}, abstract = {Standardized reporting is more and more routinely implemented in clinical practice and such structured reports have a major impact on a large variety of medical fields, e.g. laboratory medicine, pathology, and, recently, radiology. Notably, the field of nuclear medicine is constantly evolving, as novel radiotracers for numerous clinical applications are developed. Thus, framework systems for standardized reporting in this field may a) increase clinical acceptance of new radiotracers, b) allow for inter- and intra-center comparisons for quality assurance, and c) may be used in (global) multi-center studies to ensure comparable results and enable efficient data abstraction. In the last two years, several standardized framework systems for positron emission tomography (PET) radiotracers with potential theranostic applications have been proposed. These include systems for prostate-specific membrane antigen (PSMA)-targeted PET agents for the diagnosis and treatment of prostate cancer (PCa) and somatostatin receptor (SSTR)-targeted PET agents for the diagnosis and treatment of neuroendocrine neoplasias. In the present review, those standardized framework systems for PSMA- and SSTR-targeted PET will be briefly introduced followed by an overview of their advantages and limitations. In addition, potential applications will be defined, approaches to validate such concepts will be proposed, and future perspectives will be discussed.}, subject = {Positronen-Emissions-Tomografie}, language = {en} } @phdthesis{Kreter2019, author = {Kreter, Michael}, title = {Targeting the mystery of extragalactic neutrino sources - A Multi-Messenger Window to the Extreme Universe -}, doi = {10.25972/OPUS-17984}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-179845}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Active Galactic Nuclei (AGNs) are among the most powerful and most intensively studied objects in the Universe. AGNs harbor a mass accreting supermassive black hole (SMBH) in their center and emit radiation throughout the entire electromagnetic spectrum. About 10\% show relativistic particle outflows, perpendicular to the so-called accretion disk, which are known as jets. Blazars, a subclass of AGN with jet orientations close to the line-of-sight of the observer, are highly variable sources from radio to TeV energies and dominate the γ- ray sky. The overall observed broadband emission of blazars is characterized by two distinct emission humps. While the low-energy hump is well described by synchrotron radiation of relativistic electrons, both leptonic processes such as inverse Compton scattering and hadronic processes such as pion-photoproduction can explain the radiation measured in the high-energy hump. Neutrinos, neutral, nearly massless particles, which only couple to the weak force 1 are exclusively produced in hadronic interactions of protons accelerated to relativistic energies. The detection of a high-energy neutrino from an AGN would provide an irrefutable proof of hadronic processes happening in jets. Recently, the IceCube neutrino observatory, located at the South Pole with a total instrumented volume of about one km 3 , provided evidence for a diffuse high-energy neutrino flux. Since the atmospheric neutrino spectrum falls steeply with energy, individual events with the clearest signature of coming from an extraterrestrial origin are those at the highest energies. These events are uniformly distributed over the entire sky and are therefore most likely of extragalactic nature. While the neutrino event (known as "BigBird") with a reconstructed energy of ∼ 2 PeV has already been detected in temporal and spatial agreement with a single blazar in an active phase, still, the chance coincidence for such an association is only on the order of ∼ 5\%. The neutrino flux at these high energies is low, so that even the brightest blazars only yield a Poisson probability clearly below unity. Such a small probability is in agreement with the observed all-sky neutrino flux otherwise, the sky would already be populated with numerous confirmed neutrino point sources. In neutrino detectors, events are typically detected in two different signatures 2 . So-called shower-like electron neutrino events produce a large particle cascade, which leads to a pre- cise energy measurement, but causes a large angular uncertainty. Track-like muon neutrino events, however, only produce a single trace in the detector, leading to a precise localization but poor energy reconstruction. The "BigBird" event was a shower-like neutrino event, tem- porally coincident with an activity phase of the blazar PKS 1424-418, lasting several months. Shower-like neutrino events typically lead to an angular resolution of ∼ 10 ◦ , while track-like events show a localization uncertainty of only ∼ 1 ◦ . Considering the potential detection of a track-like neutrino event in agreement with an activity phase of a single blazar lasting only days would significantly decrease the chance coincidence of such an association. In this thesis, a sample of bright blazars, continuously monitored by Fermi/LAT in the MeV to GeV regime, is considered as potential neutrino candidates. I studied the maximum possible neutrino ex- pectation of short-term blazar flares with durations of days to weeks, based on a calorimetric argumentation. I found that the calorimetric neutrino output of most short-term blazar flares is too small to lead to a substantial neutrino detection. However, for the most extreme flares, Poisson probabilities of up to ∼ 2\% are reached, so that the possibility of associated neutrino detections in future data unblindings of IceCube and KM3NeT seems reasonable. On 22 September 2017, IceCube detected the first track-like neutrino event (named IceCube- 170922A) coincident with a single blazar in an active phase. From that time on, the BL Lac object TXS 0506+056 was subject of an enormous multiwavelength campaign, revealing an en- hanced flux state at the time of the neutrino arrival throughout several different wavelengths. In this thesis, I first studied the long-term flaring behavior of TXS 0506+056, using more than nine years of Fermi/LAT data. I found that the activity phase in the MeV to GeV regime already started in early 2017, months before the arrival of IceCube-170922A. I performed a calorimetric analysis on a 3-day period around the neutrino arrival time and found no sub- stantial neutrino expectation from such a short time range. By computing the calorimetric neutrino prediction for the entire activity phase of TXS 0506+056 since early 2017, a possible association seems much more likely. However, the post-trial corrected chance coincidence for a long-term association between IceCube-170922A and the blazar TXS 0506+056 is on the level of ∼ 3.5 σ, establishing TXS 0506+056 as the most promising neutrino point source candidate in the scientific community. Another way to explain a high-energy neutrino signal without an observed astronomical counterpart, would be the consideration of blazars at large cosmological distances. These high-redshift blazars are capable of generating the observed high-energy neutrino flux, while their γ-ray emission would be efficiently downscattered by Extragalactic Background Light (EBL), making them almost undetectable to Fermi/LAT. High-redshift blazars are impor- tant targets, as they serve as cosmological probes and represent one of the most powerful classes of γ-ray sources in the Universe. Unfortunately, only a small number of such objects could be detected with Fermi/LAT so far. In this thesis, I perform a systematic search for flaring events in high-redshift γ-ray blazars, which long-term flux is just below the sensitiv- ity limit of Fermi/LAT. By considering a sample of 176 radio detected high-redshift blazars, undetected at γ-ray energies, I was able to increase the number of previously unknown γ-ray blazars by a total of seven sources. Especially the blazar 5BZQ J2219-2719, at a distance of z = 3.63 was found to be the most distant new γ-ray source identified within this thesis. In the final part of this thesis, I studied the flaring behavior of bright blazars, previously considered as potential neutrino candidates. While the occurrence of flaring intervals in blazars is of purely statistical nature, I found potential differences in the observed flaring behavior of different blazar types. Blazars can be subdivided into BL Lac (BLL) objects, Flat-Spectrum Radio Quasar (FSRQ) and Blazars Candidates of Uncertain type (BCU). FSRQs are typ- ically brighter than BL Lac or BCU type blazars, thus longer flares and more complicated substructures can be resolved. Although BL Lacs and BCUs are capable of generating signifi- cant flaring episodes, they are often identified close to the detection threshold of Fermi/LAT. Long-term outburst periods are exclusively observed in FSRQs, while BCUs can still con- tribute with flare durations of up to ten days. BL Lacs, however, are only detected in flaring states of less than four days. FSRQs are bright enough to be detected multiple times with time gaps between two subsequent flaring intervals ranging between days and months. While BL Lacs can show time gaps of more than 100 days, BCUs are only observed with gaps up to 20 days, indicating that these objects are detected only once in the considered time range of six years. The newly introduced parameter "Boxyness" describes the averaged flux in an identified flaring state and does highly depend on the shape of the considered flare. While perfectly box-like flares (flares which show a constant flux level over the entire time range) correspond to an averaged flux which is equal the maximum flare amplitude, irregular shaped flares generate a smaller averaged flux. While all blazar types show perfectly box-shaped daily flares, BL Lacs and BCUs are typically not bright enough to be resolved for multiple days. The work presented in this thesis illustrates the challenging state of multimessenger neu- trino astronomy and the demanding hunt for the first extragalactic neutrino point sources. In this context, this work discusses the multiwavelength emission behavior of blazars as a promising class of neutrino point sources and allows for predictions of current and future source associations}, language = {en} } @phdthesis{Kruber2019, author = {Kruber, Philip}, title = {Functional analysis of DROSHA and SIX1 mutations in kidney development and Wilms tumor}, doi = {10.25972/OPUS-16141}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-161418}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Wilms tumor (WT) is the most common kidney cancer in childhood. It is a genetically heterogeneous tumor and several genetic alterations have been identified in WT patients. Recurrent mutations were found in the homeo-domain of SIX1 and SIX2 in high proliferative tumors (18.1\% of the blastemal-type tumors) as well as in the microprocessor genes DROSHA and DGCR8 (18.2\% of the blastemal-type tumors), indicating a critical role of the SIX-SALL pathway and aberrant miRNA processing in WT formation. Underlined by the fact that a significant overlap between mutations in DROSHA and SIX1 was found, indicating a synergistic effect. To characterize the in vivo role of DROSHA and SIX mutations during kidney development and their oncogenic potential, I analyzed mouse lines with either a targeted deletion of Drosha or an inducible expression of human DROSHA or SIX1 carrying a tumor-specific E1147K or Q177R mutation, respectively. The DROSHA mutation E1147K was predicted to act in a dominant negative manner. Six2-cre mediated deletion of Drosha in nephron progenitors led to a lethal phenotype with apoptotic loss of progenitor cells and early termination of nephrogenesis. Mosaic deletions via Wt1-creERT2 resulted in a milder phenotype with viable offspring that developed proteinuria after 2-4 weeks, but no evidence of tumor formation. Activation of the DROSHA-E1147K transgene via Six2-cre, on the other hand, induced a more severe phenotype with apoptosis of progenitor cells, proteinuria and glomerular sclerosis. The severely growth-retarded mice died within the first two months. This strong phenotype was consistent with the predicted dominant-negative effect of DROSHA-E1147K. Analysis of the SIX1-Q177R mutation suggested that the mutation leads to a shift in DNA binding specificity instead of a complete loss of DNA binding. This may end up in subtle changes of the gene regulatory capacity of SIX1. Six2-cre mediated activation of SIX1-Q177R lead to a viable phenotype with no alterations or shortened life span. Yet a global activation of SIX1-Q177R mediated by Zp3-cre resulted in bilateral hydronephrosis and juvenile death of the mice. To mimic the synergistic effect of DROSHA and SIX1 mutations, I generated compound mutants in two combinations: A homozygous deletion of Drosha combined with an activation of SIX1-Q177R and a compound mutant with activation of DROSHA-E1147K and SIX1-Q177R. Each mouse model variant displayed new phenotypical alterations. Mice with Six2-cre mediated homozygous deletion of Drosha and activation of SIX1-Q177R were not viable, yet heterozygous deletion of Drosha and activation of SIX1-Q177R led to hydronephrosis, proteinuria and an early death around stage P28. Combined activation of DROSHA-E1147K and SIX1-Q177R under Six2-cre resulted in proteinuria, glomerulosclerosis and lesions inside the kidney. These mice also suffered from juvenile death. Both mouse models could confirm the predicted synergistic effect. While these results underscore the importance of a viable self-renewing progenitor pool for kidney development, there was no evidence of tumor formation. This suggests that either additional alterations in mitogenic or antiapoptotic pathways are needed for malignant transformation, or premature loss of a susceptible target cell population and early lethality prevent WT formation.}, subject = {Nephroblastom}, language = {en} } @phdthesis{Elsaesser2019, author = {Els{\"a}sser, Sebastian}, title = {Lattice dynamics and spin-phonon coupling in the multiferroic oxides Eu(1-x)Ho(x)MnO3 and ACrO2}, doi = {10.25972/OPUS-17971}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-179719}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The focus of this thesis is the investigation of the lattice dynamics and the coupling of magnetism and phonons in two different multiferroic model systems. The first system, which constitutes the main part in this work is the system of multiferroic manganites RMnO\$_{3}\$, in particular Eu\$_{1-x}\$Ho\$_{x}\$MnO\$_{3}\$ with \$0 \le x \le 0.5\$. Its cycloidal spin arrangement leads to the emergence of the ferroelectric polarization via the inverse Dzyaloshinskii-Moriya interaction. This system is special among RMnO\$_{3}\$ as with increasing Ho content \$x\$, Eu\$_{1-x}\$Ho\$_{x}\$MnO\$_{3}\$ does not only become multiferroic, but due to the exchange interaction with the magnetic Ho-ion, the spin cycloid (and with it the electric polarization) is also flipped for higher Ho contents. This makes it one of the first compounds, where the cycloidal reorientation happens spontaneously, rather than with the application of external fields. On the other hand, there is the delafossite ACrO\$_{2}\$ system. Here, due to symmetry reasons, the spin-spiral pattern can not induce the polarization according to the inverse Dzyaloshinskii-Moriya interaction mechanism. Instead, it is thought that another way of magnetoelectric coupling is involved, which affects the charge distribution in the \$d-p\$ hybridized orbitals of the bonds. The lattice vibrations as well as the quasi-particle of the multiferroic phase, the electromagnon, are studied by Raman spectroscopy. Lattice vibrations like the B\$_{3g}\$(1) mode, which involves vibrations of the Mn-O-Mn bonds modulate the exchange interaction and serve as a powerful tool for the investigation of magnetic correlations effects with high frequency accuracy. Raman spectroscopy acts as a local probe as even local magnetic correlations directly affect the phonon vibration frequency, revealing coupling effects onto the lattice dynamics even in the absence of global magnetic order. By varying the temperature, the coupling is investigated and unveils a renormalization of the phonon frequency as the magnetic order develops. For Eu\$_{1-x}\$Ho\$_{x}\$MnO\$_{3}\$, the analysis of this spin-induced phonon frequency renormalization enables the quantitative determination of the in-plane spin-phonon coupling strengths. This formalism, introduced by Granado et al., is extended here to evaluate the out-of-plane coupling strengths, which is enabled by the identification of a previously elusive feature as a vibrational mode. The complete picture is obtained by studying the lattice- and electromagnon dynamics in the magnetic field. Further emphasis is put towards the development of the cycloidal spin structure and correlations with temperature. A new model of describing the temperature-dependent behavior of said spin correlations is proposed and can consistently explain ordering phenomena which were until now unaddressed. The results are underscored with Monte Carlo based simulations of the spin dynamics with varying temperature. Furthermore, a novel effect of a tentative violation of the Raman selection rules in Eu\$_{1-x}\$Ho\$_{x}\$MnO\$_{3}\$ was discovered. While the phonon modes can be separated and identified by their symmetry by choosing appropriate polarization configurations, in a very narrow temperature range, Eu\$_{1-x}\$Ho\$_{x}\$MnO\$_{3}\$ shows an increase of phonon intensities in polarization configurations where they should be forbidden. This is interpreted as a sign of local disorder, caused by 90° domain walls and could be explained within the model framework. This course of action is followed with the material system of delafossites ACrO\$_{2}\$. Being a relatively new class of multiferroic materials, the investigations on ACrO\$_{2}\$ are also of characterizing nature. For this, shell model calculations are performed as a reference to compare the vibrational frequencies obtained by the Raman experiments to. A renormalization of the vibrational frequencies is observed in this system as well and systematically analyzed across the sample series of \textit{A}=Cu, Pd and Ag. Eventually, the effect of applying an external magnetic field is studied. A particularly interesting feature specific for CuCrO\$_{2}\$ is a satellite peak which appears at lower temperatures. It is presumably related to a deformation of the lattice and therefore going to be discussed in further detail.}, subject = {Festk{\"o}rperphysik}, language = {en} } @phdthesis{Kiser2019, author = {Kiser, Dominik Pascal}, title = {Gene x Environment Interactions in Cdh13-deficient Mice: CDH13 as a Factor for Adaptation to the Environment}, doi = {10.25972/OPUS-17959}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-179591}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Neurodevelopmental disorders, including attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are disorders of mostly unknown etiopathogenesis, for which both genetic and environmental influences are expected to contribute to the phenotype observed in patients. Changes at all levels of brain function, from network connectivity between brain areas, over neuronal survival, synaptic connectivity and axonal growth, down to molecular changes and epigenetic modifications are suspected to play a key roles in these diseases, resulting in life-long behavioural changes. Genome-wide association as well as copy-number variation studies have linked cadherin-13 (CDH13) as a novel genetic risk factor to neuropsychiatric and neurodevelopmental disorders. CDH13 is highly expressed during embryonic brain development, as well as in the adult brain, where it is present in regions including the hippocampus, striatum and thalamus (among others) and is upregulated in response to chronic stress exposure. It is however unclear how CDH13 interacts with environmentally relevant cues, including stressful triggers, in the formation of long-lasting behavioural and molecular changes. It is currently unknown how the environment influences CDH13 and which long term changes in behaviour and gene expression are caused by their interaction. This work therefore investigates the interaction between CDH13 deficiency and neonatal maternal separation (MS) in mice with the aim to elucidate the function of CDH13 and its role in the response to early-life stress (ELS). For this purpose, mixed litters of wild-type (Cdh13+/+), heterozygous (Cdh13+/-) and homozygous knockout (Cdh13-/-) mice were maternally separated from postnatal day 1 (PN1) to postnatal day 14 (PN14) for 3 hours each day (180MS; PN1-PN14). In a first series of experiments, these mice were subjected to a battery of behavioural tests starting at 8 weeks of age in order to assess motor activity, memory functions as well as measures of anxiety. Subsequently, expression of RNA in various brain regions was measured using quantitativ real-time polymerase chain reaction (qRT-PCR). A second cohort of mice was exposed to the same MS procedure, but was not behaviourally tested, to assess molecular changes in hippocampus using RNA sequencing. Behavioural analysis revealed that MS had an overall anxiolytic-like effect, with mice after MS spending more time in the open arms of the elevated-plus-maze (EPM) and the light compartment in the light-dark box (LDB). As a notable exception, Cdh13-/- mice did not show an increase of time spent in the light compartment after MS compared to Cdh13+/+ and Cdh13+/- MS mice. During the Barnes-maze learning task, mice of most groups showed a similar ability in learning the location of the escape hole, both in terms of primary latency and primary errors. Cdh13-/- control (CTRL) mice however committed more primary errors than Cdh13-/- MS mice. In the contextual fear conditioning (cFC) test, Cdh13-/- mice showed more freezing responses during the extinction recall, indicating a reduced extinction of fear memory. In the step-down test, an impulsivity task, Cdh13-/- mice had a tendency to wait longer before stepping down from the platform, indicative of more hesitant behaviour. In the same animals, qRT-PCR of several brain areas revealed changes in the GABAergic and glutamatergic systems, while also highlighting changes in the gatekeeper enzyme Glykogensynthase-Kinase 3 (Gsk3a), both in relation to Cdh13 deficiency and MS. Results from the RNA sequencing study and subsequent gene-set enrichment analysis revealed changes in adhesion and developmental genes due to Cdh13 deficiency, while also highlighting a strong link between CDH13 and endoplasmatic reticulum function. In addition, some results suggest that MS increased pro-survival pathways, while a gene x environment analysis showed alterations in apoptotic pathways and migration, as well as immune factors and membrane metabolism. An analysis of the overlap between gene and environment, as well as their interaction, highlighted an effect on cell adhesion factors, underscoring their importance for adaptation to the environment. Overall, the stress model resulted in increased stress resilience in Cdh13+/+ and Cdh13+/- mice, a change absent in Cdh13-/- mice, suggesting a role of CDH13 during programming and adaptation to early-life experiences, that can results in long-lasting consequences on brain functions and associated behaviours. These changes were also visible in the RNA sequencing, where key pathways for cell-cell adhesion, neuronal survival and cell-stress adaptation were altered. In conclusion, these findings further highlight the role of CDH13 during brain development, while also shedding light on its function in the adaptation and response during (early life) environmental challenges.}, subject = {Cadherine}, language = {en} } @article{WagnerEikenHaubitzetal.2019, author = {Wagner, Johanna and Eiken, Barbara and Haubitz, Imme and Lichthardt, Sven and Matthes, Niels and L{\"o}b, Stefan and Klein, Ingo and Germer, Christoph-Thomas and Wiegering, Armin}, title = {Suprapubic bladder drainage and epidural catheters following abdominal surgery—a risk for urinary tract infections?}, series = {PLoS ONE}, volume = {14}, journal = {PLoS ONE}, number = {1}, doi = {10.1371/journal.pone.0209825}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177731}, pages = {e0209825}, year = {2019}, abstract = {Background Epidural catheters are state of the art for postoperative analgesic in abdominal surgery. Due to neurolysis it can lead to postoperative urinary tract retention (POUR), which leads to prolonged bladder catheterization, which has an increased risk for urinary tract infections (UTI). Our aim was to identify the current perioperative management of urinary catheters and, second, to identify the optimal time of suprapubic bladder catheter removal in regard to the removal of the epidural catheter. Methods We sent a questionnaire to 102 German hospitals and analyzed the 83 received answers to evaluate the current handling of bladder drainage and epidural catheters. Then, we conducted a retrospective study including 501 patients, who received an epidural and suprapubic catheter after abdominal surgery at the University Hospital W{\"u}rzburg. We divided the patients into three groups according to the point in time of suprapubic bladder drainage removal in regard to the removal of the epidural catheter and analyzed the onset of a UTI. Results Our survey showed that in almost all hospitals (98.8\%), patients received an epidural catheter and a bladder drainage after abdominal surgery. The point in time of urinary catheter removal was equally distributed between before, simultaneously and after the removal of the epidural catheter (respectively: ~28-29\%). The retrospective study showed a catheter-associated UTI in 6.7\%. Women were affected significantly more often than men (10,7\% versus 2,5\%, p<0.001). There was a non-significant trend to more UTIs when the suprapubic catheter was removed after the epidural catheter (before: 5.7\%, after: 8.4\%). Conclusion The point in time of suprapubic bladder drainage removal in relation to the removal of the epidural catheter does not seem to correlate with the rate of UTIs. The current handling in Germany is inhomogeneous, so further studies to standardize treatment are recommended.}, language = {en} } @article{WestermannVenturiniSellinetal.2019, author = {Westermann, Alexander J. and Venturini, Elisa and Sellin, Mikael E. and F{\"o}rstner, Konrad U. and Hardt, Wolf-Dietrich and Vogel, J{\"o}rg}, title = {The major RNA-binding protein ProQ impacts virulence gene expression in Salmonella enterica serovar Typhimurium}, series = {mBio}, volume = {10}, journal = {mBio}, number = {1}, doi = {10.1128/mBio.02504-18}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177722}, pages = {e02504-18}, year = {2019}, abstract = {FinO domain proteins such as ProQ of the model pathogen Salmonella enterica have emerged as a new class of major RNA-binding proteins in bacteria. ProQ has been shown to target hundreds of transcripts, including mRNAs from many virulence regions, but its role, if any, in bacterial pathogenesis has not been studied. Here, using a Dual RNA-seq approach to profile ProQ-dependent gene expression changes as Salmonella infects human cells, we reveal dysregulation of bacterial motility, chemotaxis, and virulence genes which is accompanied by altered MAPK (mitogen-activated protein kinase) signaling in the host. Comparison with the other major RNA chaperone in Salmonella, Hfq, reinforces the notion that these two global RNA-binding proteins work in parallel to ensure full virulence. Of newly discovered infection-associated ProQ-bound small noncoding RNAs (sRNAs), we show that the 3′UTR-derived sRNA STnc540 is capable of repressing an infection-induced magnesium transporter mRNA in a ProQ-dependent manner. Together, this comprehensive study uncovers the relevance of ProQ for Salmonella pathogenesis and highlights the importance of RNA-binding proteins in regulating bacterial virulence programs. IMPORTANCE The protein ProQ has recently been discovered as the centerpiece of a previously overlooked "third domain" of small RNA-mediated control of gene expression in bacteria. As in vitro work continues to reveal molecular mechanisms, it is also important to understand how ProQ affects the life cycle of bacterial pathogens as these pathogens infect eukaryotic cells. Here, we have determined how ProQ shapes Salmonella virulence and how the activities of this RNA-binding protein compare with those of Hfq, another central protein in RNA-based gene regulation in this and other bacteria. To this end, we apply global transcriptomics of pathogen and host cells during infection. In doing so, we reveal ProQ-dependent transcript changes in key virulence and host immune pathways. Moreover, we differentiate the roles of ProQ from those of Hfq during infection, for both coding and noncoding transcripts, and provide an important resource for those interested in ProQ-dependent small RNAs in enteric bacteria.}, language = {en} } @phdthesis{Tiwarekar2019, author = {Tiwarekar, Vishakha Rakesh}, title = {The APOBEC3G-regulated host factors REDD1 and KDELR2 restrict measles virus replication}, doi = {10.25972/OPUS-17952}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-179526}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Measles is an extremely contagious vaccine-preventable disease responsible for more than 90000 deaths worldwide annually. The number of deaths has declined from 8 million in the pre-vaccination era to few thousands every year due to the highly efficacious vaccine. However, this effective vaccine is still unreachable in many developing countries due to lack of infrastructure, while in developed countries too many people refuse vaccination. Specific antiviral compounds are not yet available. In the current situation, only an extensive vaccination approach along with effective antivirals could help to have a measles-free future. To develop an effective antiviral, detailed knowledge of viral-host interaction is required. This study was undertaken to understand the interaction between MV and the innate host restriction factor APOBEC3G (A3G), which is well-known for its activity against human immunodeficiency virus (HIV). Restriction of MV replication was not attributed to the cytidine deaminase function of A3G, instead, we identified a novel role of A3G in regulating cellular gene functions. Among two of the A3G regulated host factors, we found that REDD1 reduced MV replication, whereas, KDELR2 hampered MV haemagglutinin (H) surface transport thereby affecting viral release. REDD1, a negative regulator of mTORC1 signalling impaired MV replication by inhibiting mTORC1. A3G regulated REDD1 expression was demonstrated to inversely correlate with MV replication. siRNA mediated silencing of A3G in primary human blood lymphocytes (PBL) reduced REDD1 levels and simultaneously increased MV titres. Also, direct depletion of REDD1 improved MV replication in PBL, indicating its role in A3G mediated restriction of MV. Based on these finding, a new role of rapamycin, a pharmacological inhibitor of mTORC1, was uncovered in successfully diminishing MV replication in Vero as well as in human PBL. The ER and Golgi resident receptor KDELR2 indirectly affected MV by competing with MV-H for cellular chaperones. Due to the sequestering of chaperones by KDELR2, they can no longer assist in MV-H folding and subsequent surface expression. Taken together, the two A3G-regulated host factors REDD1 and KDELR2 are mainly responsible for mediating its antiviral activity against MV.}, language = {en} } @phdthesis{Riad2019, author = {Riad, Noura}, title = {The Development of Dualsteric Ligands for the Elucidation of Mode of Activation of Muscarinic Receptors and their Selective Signaling}, doi = {10.25972/OPUS-17928}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-179282}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {GPCRs, particularly muscarinic receptors (mAChRs), are significant therapeutic targets in many physiological conditions. The significance of dualsteric hybrids selectively targeting mAChR subtypes is their great advantage in avoiding undesired side effects. This is attained by exploitation of the high affinity of ligand-binding to the orthosteric site and the structural diversity of the allosteric site to target an individual mAChR subtype, as well as offering signal bias to avoiding undesired transduction pathways. Furthermore, dualsteric targeting of mAChR subtypes helps in the elucidation of the physiological role of each individual mAChR subtype. The first project was the attempt of synthesis of the M2-preferring ligand AFDX-384. AFDX-384 is known to preferentially bind to the M2 receptor subtype as an orthosteric antagonist, with partial interaction with residues in the allosteric site. This project aimed to re-trace the synthesis route of AFDX-384, to open the door to its upscaling and the future synthesis of AFDX-type dualsteric ligands. The multi-step synthesis of AFDX-384 is achieved through the synthesis of its 2 precursors, the chloro acyl derivative VIII and the piperidinyl derivative IV. Upscaled synthesis of the piperidinyl derivative IV was attained. Synthesis of the chloro acyl compound VIII was attempted. Several trials to synthesize the benzopyridodiazepine nucleus as well as its chloro-acylation resulted in the production of the novel crystal structures V and VI. X-ray crystallography was also done for crystallized molecules of the closed-ring benzopyridodiazepine VII that was previously synthesized. Chloro-acylation reactions of compound VII using phosgene seem to be attainable when done using reflux overnight. However, the use of methanol to aid in elution during silica gel column chromatography converted the expected product to the carbamate analogue IX. Hence, further attempts in purification should refrain from the use of methanol. The use of triphosgene instead of phosgene demonstrates a cleaner route for further upscaled synthesis. The second project was the synthesis of dualsteric ligands involving variable orthosteric and allosteric moieties. Four different types of hybrids have been created over multiple steps. Dualsteric ligands have been synthesized using either a phthalimido- or 1,8-naphthalimidopropylamino moiety as the allosteric-binding group, coupled to either N-desmethyl pirenzepine or N-desmethyl clozapine using variable chain lengths. Furthermore, the synthesis of the dualsteric ligands involving N-desmethyl clozapine linked to either the super-agonist iperoxo or acetylcholine, and being connected using variable alkane chain lengths. Several reaction conditions have been investigated throughout the analysis of the optimal condition to conduct the critical final step of synthesis of these dualsteric hybrids, which involves the linking of the two segments of the hybrid together. The optimal method, which produced the least side products and highest yield, was to connect the two intermediates of the compound in absence of base, catalyst or microwaves while stirring at 35 °C for several days using acetonitrile as solvent (silica gel TLC monitoring, 0.2 M aqueous KNO3/MeOH 2:3). The ideal purification methods for the final compounds were found to be either crystallization from the reaction medium or using C18 reverse phase silica gel flash chromatography (using H2O/MeOH solvent system). All the hybrids will be subjected to pharmacological testing using the appropriate FRET assays.}, subject = {Muscarinrezeptor}, language = {en} } @article{SuchotzkiKakavandGamer2019, author = {Suchotzki, Kristina and Kakavand, Aileen and Gamer, Matthias}, title = {Validity of the reaction time concealed information test in a prison sample}, series = {Frontiers in Psychiatry}, volume = {9}, journal = {Frontiers in Psychiatry}, number = {745}, doi = {10.3389/fpsyt.2018.00745}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177714}, year = {2019}, abstract = {Detecting whether a suspect possesses incriminating (e.g., crime-related) information can provide valuable decision aids in court. To this means, the Concealed Information Test (CIT) has been developed and is currently applied on a regular basis in Japan. But whereas research has revealed a high validity of the CIT in student and normal populations, research investigating its validity in forensic samples in scarce. This applies even more to the reaction time-based CIT (RT-CIT), where no such research is available so far. The current study tested the application of the RT-CIT for an imaginary mock crime scenario both in a sample of prisoners (n = 27) and a matched control group (n = 25). Results revealed a high validity of the RT-CIT for discriminating between crime-related and crime-unrelated information, visible in medium to very high effect sizes for error rates and reaction times. Interestingly, in accordance with theories that criminal offenders may have worse response inhibition capacities and that response inhibition plays a crucial role in the RT-CIT, CIT-effects in the error rates were even elevated in the prisoners compared to the control group. No support for this hypothesis could, however, be found in reaction time CIT-effects. Also, performance in a standard Stroop task, that was conducted to measure executive functioning, did not differ between both groups and no correlation was found between Stroop task performance and performance in the RT-CIT. Despite frequently raised concerns that the RT-CIT may not be applicable in non-student and forensic populations, our results thereby do suggest that such a use may be possible and that effects seem to be quite large. Future research should build up on these findings by increasing the realism of the crime and interrogation situation and by further investigating the replicability and the theoretical substantiation of increased effects in non-student and forensic samples.}, language = {en} } @article{GoosDejungWehmanetal.2019, author = {Goos, Carina and Dejung, Mario and Wehman, Ann M. and M-Natus, Elisabeth and Schmidt, Johannes and Sunter, Jack and Engstler, Markus and Butter, Falk and Kramer, Susanne}, title = {Trypanosomes can initiate nuclear export co-transcriptionally}, series = {Nucleic Acids Research}, volume = {47}, journal = {Nucleic Acids Research}, number = {1}, doi = {10.1093/nar/gky1136}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177709}, pages = {266-282}, year = {2019}, abstract = {The nuclear envelope serves as important messenger RNA (mRNA) surveillance system. In yeast and human, several control systems act in parallel to prevent nuclear export of unprocessed mRNAs. Trypanosomes lack homologues to most of the involved proteins and their nuclear mRNA metabolism is non-conventional exemplified by polycistronic transcription and mRNA processing by trans-splicing. We here visualized nuclear export in trypanosomes by intra- and intermolecular multi-colour single molecule FISH. We found that, in striking contrast to other eukaryotes, the initiation of nuclear export requires neither the completion of transcription nor splicing. Nevertheless, we show that unspliced mRNAs are mostly prevented from reaching the nucleus-distant cytoplasm and instead accumulate at the nuclear periphery in cytoplasmic nuclear periphery granules (NPGs). Further characterization of NPGs by electron microscopy and proteomics revealed that the granules are located at the cytoplasmic site of the nuclear pores and contain most cytoplasmic RNA-binding proteins but none of the major translation initiation factors, consistent with a function in preventing faulty mRNAs from reaching translation. Our data indicate that trypanosomes regulate the completion of nuclear export, rather than the initiation. Nuclear export control remains poorly understood, in any organism, and the described way of control may not be restricted to trypanosomes.}, language = {en} } @techreport{ImgrundJanieschFischeretal.2019, author = {Imgrund, Florian and Janiesch, Christian and Fischer, Marcus and Winkelmann, Axel}, title = {Success Factors for Process Modeling Projects: An Empirical Analysis}, doi = {10.25972/OPUS-17924}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-179246}, pages = {68}, year = {2019}, abstract = {Business process modeling is one of the most crucial activities of BPM and enables companies to realize various benefits in terms of communication, coordination, and distribution of organizational knowledge. While numerous techniques support process modeling, companies frequently face challenges when adopting BPM to their organization. Existing techniques are often modified or replaced by self-developed approaches so that companies cannot fully exploit the benefits of standardization. To explore the current state of the art in process modeling as well as emerging challenges and potential success factors, we conducted a large-scale quantitative study. We received feedback from 314 respondents who completed the survey between July 2 and September 6, 2017. Thus, our study provides in-depth insights into the status quo of process modeling and allows us to provide three major contributions. Our study suggests that the success of process modeling projects depends on four major factors, which we extracted using exploratory factor analysis. We found employee education, management involvement, usability of project results, and the companies' degree of process orientation to be decisive for the success of a process modeling project. We conclude this report with a summary of results and present potential avenues for future research. We thereby emphasize the need of quantitative and qualitative insights to process modeling in practice is needed to strengthen the quality of process modeling in practice and to be able to react quickly to changing conditions, attitudes, and possible constraints that practitioners face.}, language = {en} } @article{PetschkeHelmStaab2019, author = {Petschke, Danny and Helm, Ricardo and Staab, Torsten E.M.}, title = {Data on pure tin by Positron Annihilation Lifetime Spectroscopy (PALS) acquired with a semi-analog/digital setup using DDRS4PALS}, series = {Data in Brief}, volume = {22}, journal = {Data in Brief}, doi = {10.1016/j.dib.2018.11.121}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177698}, pages = {16-29}, year = {2019}, abstract = {Positron annihilation lifetime spectroscopy (PALS) provides a powerful technique for non-destructive microstructure investigations in a broad field of material classes such as metals, semiconductors, polymers or porous glasses. Even though this method is well established for more than five decades, no proper standardization for the used setup configuration and subsequent data processing exists. Eventually, this could lead to an insufficiency of data reproducibility and avoidable deviations. Here we present experimentally obtained and simulated data of positron lifetime spectra at various statistics measured on pure tin (4N-Sn) by using a semi-analog/digital setup, where the digital section consists of the DRS4 evaluation board, "Design and performance of the 6 GHz waveform digitizing chip DRS4" [1]. The analog section consists of nuclear instrument modules (NIM), which externally trigger the DRS4 evaluation board to reduce the digitization and, thus, increase the acquisition efficiency. For the experimentally obtained lifetime spectra, 22Na sealed in Kapton foil served as a positron source, whereas 60Co was used for the acquisition of the prompt spectrum, i.e. the quasi instrument response function. Both types of measurements were carried out under the same conditions. All necessary data and information regarding the data acquisition and data reduction are provided to allow reproducibility by other research groups.}, language = {en} } @article{LinsenmannMonoranuAlkonyietal.2019, author = {Linsenmann, Thomas and Monoranu, Camelia M. and Alkonyi, Balint and Westermaier, Thomas and Hagemann, Carsten and Kessler, Almuth F. and Ernestus, Ralf-Ingo and L{\"o}hr, Mario}, title = {Cerebellar liponeurocytoma - molecular signature of a rare entity and the importance of an accurate diagnosis}, series = {Interdisciplinary Neurosurgery}, volume = {16}, journal = {Interdisciplinary Neurosurgery}, doi = {10.1016/j.inat.2018.10.017}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177652}, pages = {7-11}, year = {2019}, abstract = {Background: Cerebellar liponeurocytoma is an extremely rare tumour entity of the central nervous system. It is histologically characterised by prominent neuronal/neurocytic differentiation with focal lipidisation and corresponding histologically to WHO grade II. It typically develops in adults, and usually shows a low proliferative potential. Recurrences have been reported in almost 50\% of cases, and in some cases the recurrent tumour may display increased mitotic activity and proliferation index, vascular proliferations and necrosis. Thus pathological diagnosis of liponeurocytoma is challenging. This case presentation highlights the main clinical, radiographic and pathological features of a cerebellar liponeurocytoma. Case presentation: A 59-year-old, right-handed woman presented at our department with a short history of persistent headache, vertigo and gait disturbances. Examination at presentation revealed that the patient was awake, alert and fully oriented. The cranial nerve status was normal. Uncertainties were noted in the bilateral finger-to-nose testing with bradydiadochokinesis on both sides. Strength was full and no pronator drift was observed. Sensation was intact. No signs of pyramidal tract dysfunction were detected. Her gait appeared insecure. The patient underwent surgical resection. Afterward no further disturbances could be detected. Conclusions: To date >40 cases of liponeurocytoma have been reported, including cases with supratentorial location. A review of the 5 published cases of recurrent cerebellar. Liponeurocytoma revealed that the median interval between the first and second relapse was rather short, indicating uncertain malignant potential. The most recent WHO classification of brain tumours (2016) classifies the cerebellar liponeurocytoma as a separate entity and assigns the tumour to WHO grade II. Medulloblastoma is the most important differential diagnosis commonly seen in children and young adults. In contrast, cerebellar liponeurocytoma is typically diagnosed in adults. The importance of accurate diagnosis should not be underestimated especially in the view of possible further therapeutic interventions and for the determination of the patient's prognosis.}, language = {en} } @article{BratengeierHolubyevWegener2019, author = {Bratengeier, Klaus and Holubyev, Kostyantyn and Wegener, Sonja}, title = {Steeper dose gradients resulting from reduced source to target distance—a planning system independent study}, series = {Journal of Applied Clinical Medical Physics}, volume = {20}, journal = {Journal of Applied Clinical Medical Physics}, number = {1}, doi = {10.1002/acm2.12490}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177424}, pages = {89-100}, year = {2019}, abstract = {Purpose: To quantify the contribution of penumbra in the improvement of healthy tissue sparing at reduced source-to-axis distance (SAD) for simple spherical target and different prescription isodoses (PI). Method: A TPS-independent method was used to estimate three-dimensional (3D) dose distribution for stereotactic treatment of spherical targets of 0.5 cm radius based on single beam two-dimensional (2D) film dosimetry measurements. 1 cm target constitutes the worst case for the conformation with standard Multi-Leaf Collimator (MLC) with 0.5 cm leaf width. The measured 2D transverse dose cross-sections and the profiles in leaf and jaw directions were used to calculate radial dose distribution from isotropic beam arrangement, for both quadratic and circular beam openings, respectively. The results were compared for standard (100 cm) and reduced SAD 70 and 55 cm for different PI. Results: For practical reduction of SAD using quadratic openings, the improvement of healthy tissue sparing (HTS) at distances up to 3 times the PTV radius was at least 6\%-12\%; gradient indices (GI) were reduced by 3-39\% for PI between 40\% and 90\%. Except for PI of 80\% and 90\%, quadratic apertures at SAD 70 cm improved the HTS by up to 20\% compared to circular openings at 100 cm or were at least equivalent; GI were 3\%-33\% lower for reduced SAD in the PI range 40\%-70\%. For PI = 80\% and 90\% the results depend on the circular collimator model. Conclusion: Stereotactic treatments of spherical targets delivered at reduced SAD of 70 or 55 cm using MLC spare healthy tissue around the target at least as good as treatments at SAD 100 cm using circular collimators. The steeper beam penumbra at reduced SAD seems to be as important as perfect target conformity. The authors argue therefore that the beam penumbra width should be addressed in the stereotactic studies.}, language = {en} } @article{BeykanFaniJensenetal.2019, author = {Beykan, Seval and Fani, Melpomeni and Jensen, Svend Borup and Nicolas, Guillaume and Wild, Damian and Kaufmann, Jens and Lassmann, Michael}, title = {In vivo biokinetics of \(^{177}\)Lu-OPS201 in Mice and Pigs as a Model for Predicting Human Dosimetry}, series = {Contrast Media \& Molecular Imaging}, volume = {2019}, journal = {Contrast Media \& Molecular Imaging}, doi = {10.1155/2019/6438196}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177382}, pages = {6438196}, year = {2019}, abstract = {Introduction. \(^{177}\)Lu-OPS201 is a high-affinity somatostatin receptor subtype 2 antagonist for PRRT in patients with neuroendocrine tumors. The aim is to find the optimal scaling for dosimetry and to compare the biokinetics of \(^{177}\)Lu-OPS201 in animals and humans. Methods. Data on biokinetics of \(^{177}\)Lu-OPS201 were analyzed in athymic nude Foxn1\(^{nu}\) mice (28 F, weight: 26 ± 1 g), Danish Landrace pigs (3 F-1 M, weight: 28 ± 2 kg), and patients (3 F-1 M, weight: 61 ± 17 kg) with administered activities of 0.19-0.27 MBq (mice), 97-113 MBq (pigs), and 850-1086 MBq (patients). After euthanizing mice (up to 168 h), the organ-specific activity contents (including blood) were measured. Multiple planar and SPECT/CT scans were performed until 250 h (pigs) and 72 h (patients) to quantify the uptake in the kidneys and liver. Blood samples were taken up to 23 h (patients) and 300 h (pigs). In pigs and patients, kidney protection was applied. Time-dependent uptake data sets were created for each species and organ/tissue. Biexponential fits were applied to compare the biokinetics in the kidneys, liver, and blood of each species. The time-integrated activity coefficients (TIACs) were calculated by using NUKFIT. To determine the optimal scaling, several methods (relative mass scaling, time scaling, combined mass and time scaling, and allometric scaling) were compared. Results. A fast blood clearance of the compound was observed in the first phase (<56 h) for all species. In comparison with patients, pigs showed higher liver retention. Based on the direct comparison of the TIACs, an underestimation in mice (liver and kidneys) and an overestimation in pigs' kidneys compared to the patient data (kidney TIAC: mice = 1.4 h, pigs = 7.7 h, and patients = 5.8 h; liver TIAC: mice = 0.7 h, pigs = 4.1 h, and patients = 5.3 h) were observed. Most similar TIACs were obtained by applying time scaling (mice) and combined scaling (pigs) (kidney TIAC: mice = 3.9 h, pigs = 4.8 h, and patients = 5.8 h; liver TIAC: mice = 0.9 h, pigs = 4.7 h, and patients = 5.3 h). Conclusion. If the organ mass ratios between the species are high, the combined mass and time scaling method is optimal to minimize the interspecies differences. The analysis of the fit functions and the TIACs shows that pigs are better mimicking human biokinetics.}, language = {en} } @article{MagyarWagnerThomasetal.2019, author = {Magyar, Attila and Wagner, Martin and Thomas, Phillip and Malsch, Carolin and Schneider, Reinhard and St{\"o}rk, Stefan and Heuschmann, Peter U and Leyh, Rainer G and Oezkur, Mehmet}, title = {HO-1 concentrations 24 hours after cardiac surgery are associated with the incidence of acute kidney injury: a prospective cohort study}, series = {International Journal of Nephrology and Renovascular Disease}, volume = {12}, journal = {International Journal of Nephrology and Renovascular Disease}, doi = {10.2147/IJNRD.S165308}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177250}, pages = {9-18}, year = {2019}, abstract = {Background: Acute kidney injury (AKI) is a serious complication after cardiac surgery that is associated with increased mortality and morbidity. Heme oxygenase-1 (HO-1) is an enzyme synthesized in renal tubular cells as one of the most intense responses to oxidant stress linked with protective, anti-inflammatory properties. Yet, it is unknown if serum HO-1 induction following cardiac surgical procedure involving cardiopulmonary bypass (CPB) is associated with incidence and severity of AKI. Patients and methods: In the present study, we used data from a prospective cohort study of 150 adult cardiac surgical patients. HO-1 measurements were performed before, immediately after and 24 hours post-CPB. In univariate and multivariate analyses, the association between HO-1 and AKI was investigated. Results: AKI with an incidence of 23.3\% (35 patients) was not associated with an early elevation of HO-1 after CPB in all patients (P=0.88), whereas patients suffering from AKI developed a second burst of HO-1 24 hours after CBP. In patients without AKI, the HO-1 concentrations dropped to baseline values (P=0.031). Furthermore, early HO-1 induction was associated with CPB time (P=0.046), while the ones 24 hours later lost this association (P=0.219). Conclusion: The association of the second HO-1 burst 24 hours after CBP might help to distinguish between the causality of AKI in patients undergoing CBP, thus helping to adapt patient stratification and management.}, language = {en} } @article{JahnDorbathKircheretal.2019, author = {Jahn, Daniel and Dorbath, Donata and Kircher, Stefan and Nier, Anika and Bergheim, Ina and Lenaerts, Kaatje and Hermanns, Heike M. and Geier, Andreas}, title = {Beneficial effects of vitamin D treatment in an obese mouse model of non-alcoholic steatohepatitis}, series = {Nutrients}, volume = {11}, journal = {Nutrients}, number = {1}, doi = {10.3390/nu11010077}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177222}, pages = {77}, year = {2019}, abstract = {Serum vitamin D levels negatively correlate with obesity and associated disorders such as non-alcoholic steatohepatitis (NASH). However, the mechanisms linking low vitamin D (VD) status to disease progression are not completely understood. In this study, we analyzed the effect of VD treatment on NASH in mice. C57BL6/J mice were fed a high-fat/high-sugar diet (HFSD) containing low amounts of VD for 16 weeks to induce obesity, NASH and liver fibrosis. The effects of preventive and interventional VD treatment were studied on the level of liver histology and hepatic/intestinal gene expression. Interestingly, preventive and to a lesser extent also interventional VD treatment resulted in improvements of liver histology. This included a significant decrease of steatosis, a trend towards lower non-alcoholic fatty liver disease (NAFLD) activity score and a slight non-significant decrease of fibrosis in the preventive treatment group. In line with these changes, preventive VD treatment reduced the hepatic expression of lipogenic, inflammatory and pro-fibrotic genes. Notably, these beneficial effects occurred in conjunction with a reduction of intestinal inflammation. Together, our observations suggest that timely initiation of VD supplementation (preventive vs. interventional) is a critical determinant of treatment outcome in NASH. In the applied animal model, the improvements of liver histology occurred in conjunction with reduced inflammation in the gut, suggesting a potential relevance of vitamin D as a therapeutic agent acting on the gut-liver axis.}, language = {en} } @phdthesis{HechtgebWagener2019, author = {Hecht [geb. Wagener], Reinhard Johannes}, title = {Processing and Characterization of Bulk Heterojunction Solar Cells Based on New Organic n-Type Semiconductors}, doi = {10.25972/OPUS-16138}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-161385}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {This thesis established the fabrication of organic solar cells of DA dye donors and fullerene acceptors under ambient conditions in our laboratory, however, with reduced power conversion efficiencies compared to inert conditions. It was shown that moisture had the strongest impact on the stability and reproducibility of the solar cells. Therefore, utilization of robust materials, inverted device architectures and fast fabrication/characterization are recommended if processing takes place in air. Furthermore, the dyad concept was successfully explored in merocyanine dye-fullerene dyads and power conversion efficiencies of up to 1.14 \% and 1.59 \% were measured under ambient and inert conditions, respectively. It was determined that the major drawback in comparison to comparable BHJ devices was the inability of the dyad molecules to undergo phase separation. Finally, two series of small molecules were designed in order to obtain electron transport materials, using the acceptor-core-acceptor motive. By variation of the acceptor units especially the LUMO levels could be lowered effectively. Investigation of the compounds in organic thin film transistors helped to identify promising molecules with electron transport properties. Electron transport mobilities of up to 7.3 × 10-2 cm2 V-1 s-1 (ADA2b) and 1.39 × 10-2 cm2 V-1 s-1 (AπA1b) were measured in air for the ADA and AπA dyes, respectively. Investigation of selected molecules in organic solar cells proved that these molecules work as active layer components, even though power conversion efficiencies cannot compete with fullerene based devices yet. Thus, this thesis shows new possibilities that might help to develop and design small molecules as substitutes for fullerene acceptors.}, subject = {Heterosolarzelle}, language = {en} } @phdthesis{Slotta2019, author = {Slotta, Anja Maria}, title = {The Role of Protein Kinase D 1 in the regulation of murine adipose tissue function under physiological and pathophysiological conditions}, doi = {10.25972/OPUS-17911}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-179112}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Adipocytes are specialized cells found in vertebrates to ensure survival in terms of adaption to food deficit and abundance. However, their dysfunction accounts for the pathophysiology of metabolic diseases such as T2DM. Preliminary data generated by Mona L{\"o}ffler suggested that PKD1 is involved in adipocyte function. Here, I show that PKD1 expression and activity is linked to lipid metabolism of murine adipocytes. PKD1 gene expression and activity was reduced in murine white adipose tissue upon fasting, a physiological condition which induces lipolysis. Isoproterenol-stimulated lipolysis in adipose tissue and 3T3-L1 adipocytes reduced PKD1 gene expression. Silencing ATGL in adipocytes inhibited isoproterenol-stimulated lipolysis, however, the β-adrenergic stimulation of ATGL-silenced adipocytes lowered PKD1 expression levels as well. Adipose tissue of obese mice exhibited high PKD1 RNA levels but paradoxically lower protein levels of phosphorylated PKD1-Ser916. However, HFD generated a second PKD1 protein product of low molecular weight in mouse adipose tissue. Furthermore, constitutively active PKD1 predominantly displayed nuclear localization in 3T3-L1 adipocytes containing many fat vacuoles. However, adipocytes overexpressing non-functional PKD1 contained fewer lipid droplets and PKD1-KD was distributed in cytoplasm. Most importantly, deficiency of PKD1 in mouse adipose tissue caused expression of genes involved in adaptive thermogenesis such as UCP-1 and thus generated brown-like phenotype adipocytes. Thus, PKD1 is implicated in adipose tissue function and presents an interesting target for therapeutic approaches in the prevention of obesity and associated diseases.}, subject = {adipocyte}, language = {en} } @phdthesis{Schaupp2019, author = {Schaupp, Daniel Norbert}, title = {Earnings Management in the Context of Earnings Quality, Corporate Governance and Corporate Social Responsibility}, doi = {10.25972/OPUS-15933}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159337}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Steigende Geschwindigkeit und Komplexit{\"a}t von Gesch{\"a}ftsprozessen und -beziehungen ver{\"a}ndern fundamental die Anspr{\"u}che an umfassende und werthaltige finanzielle und nicht-finanzielle Informationen {\"u}ber Unternehmen. Relevante Informationen in einem Gesch{\"a}ftsbericht m{\"u}ssen daher zunehmend Vorhersagecharakter besitzen, um ihre Daseinsberechtigung nicht zu verlieren. Die ad{\"a}quate L{\"o}sung existenter Prinzipal-Agenten- Konflikte bedarf zugleich einer detaillierten und objektiven Einsch{\"a}tzung der Leistung des Agenten, was zus{\"a}tzlich zur Wertrelevanz ein Mindestmaß an Verl{\"a}sslichkeit der berichteten Informationen bedingt. In diesem Spannungsfeld kommt den Standardsettern die Aufgabe zu, Rahmenbedingungen zu schaffen, die es dem Management erm{\"o}glichen, Spielr{\"a}ume bei der Erstellung der Berichte zu nutzen, um diesen Qualit{\"a}tsanspr{\"u}chen an Informationen {\"u}ber die aktuelle und zuk{\"u}nftige Lage des Unternehmens gerecht zu werden. Diese bewusst gesetzten M{\"o}glichkeiten der Einflussnahme durch das Management begreifen jedoch auch signifikante Risiken der opportunistisch motivierten Beeinflussung der Adressaten, welche unter der {\"U}berschrift Bilanzpolitik subsumiert werden k{\"o}nnen. Die in der empirischen Forschung g{\"a}ngige Klassifizierung unterscheidet zwischen der buchm{\"a}ßigen und realen Bilanzpolitik, wobei letztere im Vergleich eine gezielte Beeinflussung von Gesch{\"a}ftsvorf{\"a}llen und nicht deren ex-post Abbildung begreift. Kapitel 2 der vorliegenden Dissertation propagiert eine umfassende Auseinandersetzung mit der empirischen Messung von Bilanzpolitik. Das Fehlen einer zufriedenstellenden Ermittlung des aggregierten Ausmaßes von Bilanzpolitik erfordert hierbei die Anwendung verschiedener Regressionsmodelle. Im speziellen Kontext der empirischen Analyse von Bilanzpolitik im Bankensektor besteht diesbez{\"u}glich eine ausgepr{\"a}gte Heterogenit{\"a}t der verwendeten Modelle. Zugleich existiert nach wie vor keine systematische Analyse der Ans{\"a}tze und Modellierungsarten von Loan Loss Provisions, welche als elementares Vehikel der diskretion{\"a}ren Einflussnahme im Fokus der einschl{\"a}gigen Studien steht. Daher untersucht der Verfasser in Kapitel 2.1 pr{\"a}valente Modellierungsans{\"a}tze, erstellt einen Baukasten verschiedener Regressionsparameter und testet eine Vielzahl an Varianten im Hinblick auf die Validit{\"a}t der ermittelten bilanzpolitischen Gr{\"o}ßen. Eine derartige Analyse ist von elementarer Wichtigkeit f{\"u}r die Validit{\"a}t der Ergebnisse und der gezogenen Schl{\"u}sse aus empirischen Studien im Bankensektor und liefert daher einen wichtigen Beitrag zur Entwicklung und Einordnung vergangener und zuk{\"u}nftiger Analysen. Die Ergebnisse der zur Anwendung gebrachten Analysen und Tests zeigen, dass eine Vielzahl der existierenden Modelle eine ausreichende Passgenauigkeit aufweist. Jedoch sind gewisse Regressoren weniger wichtig als zun{\"a}chst angenommen. So k{\"o}nnen die Regressoren der Non-Performing Loans die Modellierung stark verbessern, w{\"a}hrend Loan Loss Reserves und Net Charge-Offs nur einen kleinen Beitrag leisten k{\"o}nnen. Im weiteren Verlauf l{\"a}sst sich zudem eine ausgepr{\"a}gte Nichtlinearit{\"a}t einzelner Regressoren aufzeigen, sowie dass ein Wechsel auf ein Modell mit Ber{\"u}cksichtigung von Endogenit{\"a}t nicht zwangsl{\"a}ufig zu einer verbesserten Modellierung f{\"u}hrt. Insgesamt kann die Studie als geeigneter Startpunkt f{\"u}r zuk{\"u}nftige Studien zu Bilanzpolitik im Bankensektor fungieren. Im anschließenden Kapitel 2.2 werden aus Gr{\"u}nden der Konsistenz Modellierung und Ergebnisse der Sch{\"a}tzung von Bilanzpolitik in nicht-finanziellen Industrien f{\"u}r die Studien in Kapitel 3 und 4 vorgestellt. Im Rahmen einer umfassenden Betrachtung der Qualit{\"a}t von Finanzinformationen sollte die bereits angesprochene Verl{\"a}sslichkeit der Rechnungslegung sichergestellt werden k{\"o}nnen. Hierbei spielt neben den Rahmenbedingungen der Rechnungslegung die Qualit{\"a}t der Attribute und Prozesse der Abschlusspr{\"u}fung eine gewichtige Rolle. Im Zuge dessen wird die Unabh{\"a}ngigkeit des externen Abschlusspr{\"u}fers von seinem Mandanten als eines der Kernattribute proklamiert, da diese Neutralit{\"a}t verleiht und simultan die Qualit{\"a}t der vollzogenen Abschlusspr{\"u}fungshandlungen erh{\"o}ht. Ein unabh{\"a}ngiger Wirtschaftspr{\"u}fer ist demzufolge besser in der Lage, das Ausmaß an Bilanzpolitik zu verringern, was wiederum eine Erh{\"o}hung der Qualit{\"a}t der Finanzinformationen nach sich zieht. Kapitel 3 widmet sich daher der Analyse der Unabh{\"a}ngigkeit von kleinen und mittelgroßen Abschlusspr{\"u}fern im deutschen Markt f{\"u}r Mandanten von {\"o}ffentlichem Interesse zwischen 2007 und 2014. Das Setting der Studie zeichnet sich dadurch aus, dass kleine und mittelgroße Wirtschaftspr{\"u}fer traditionell im Verdacht stehen, aufgrund einer eingeschr{\"a}nkten Unabh{\"a}ngigkeit von kapitalmarktorientierten Mandanten diesen ein h{\"o}heres Maß an Spielr{\"a}umen zuzugestehen, c.p., es wird eine geringere Qualit{\"a}t der Pr{\"u}fung und damit gr{\"o}ßerer Spielraum f{\"u}r Bilanzpolitik vermutet. Das europ{\"a}ische und insbesondere deutsche Umfeld qualifiziert sich durch divergente gesetzlich vorgeschriebene Schwellenwerte der Abh{\"a}ngigkeit des Wirtschaftspr{\"u}fers f{\"u}r eine differenzierte Analyse der Nichtlinearit{\"a}t der Zusammenh{\"a}nge. Des Weiteren bilden die in Deutschland pr{\"a}valenten Transparenzberichte eine profunde Datenbasis f{\"u}r die Ermittlung von Abh{\"a}ngigkeitsmaßen, die im speziellen Marktsegment eine {\"u}berlegene Messung der Abh{\"a}ngigkeit der betrachteten Pr{\"u}fer erm{\"o}glichen. Die vorliegende Arbeit in diesem Kapitel w{\"a}hlt auf Basis der pr{\"a}valenten gesetzlichen Regelungen ein nicht-lineares Forschungsdesign und legt nahe, dass kleine und mittelgroße Wirtschaftspr{\"u}fers im speziellen Marktsegment der kapitalmarktorientierten Mandanten mit steigender Abh{\"a}ngigkeit eine erh{\"o}hte Pr{\"u}fungsqualit{\"a}t liefern, bis sich die Effekte an einer hohen Schwelle der Abh{\"a}ngigkeit umkehren. Dieser Wendepunkt spiegelt zugleich formulierte gesetzliche Schwellenwerte wider. Kleinen und mittelgroße Abschlusspr{\"u}fer scheinen trotz steigender Abh{\"a}ngigkeit eine h{\"o}here Pr{\"u}fungsanstrengung zu w{\"a}hlen, welche buchm{\"a}ßige Bilanzpolitik einschr{\"a}nkt und damit die Qualit{\"a}t der Finanzinformationen erh{\"o}ht. Im Fokus steht hierbei vermutlich das Bestreben des Festigens und Ausbauens einer Reputation im Marktsegment der kapitalmarktorientierten Mandanten. Ab {\"U}berschreiten eines kritischen Schwellenwertes scheint hingegen die gestiegene Abh{\"a}ngigkeit die Reputationseffekte zu dominieren. Die Ergebnisse der Studie legen zudem den Schluss nahe, dass Mandanten bei einer Einschr{\"a}nkung der buchm{\"a}ßigen Bilanzpolitik geneigt sind mehr reale Bilanzpolitik einzusetzen, deren Einschr{\"a}nkung nicht origin{\"a}rer Gegenstand der Pr{\"u}fung durch den Abschlusspr{\"u}fer ist. Die geschilderten Ergebnisse erweisen sich als sehr robust gegen{\"u}ber zahlreichen Ver{\"a}nderungen und Tests wie etwa einer de-facto Office Level und Partner Level Analyse. Zudem kann gezeigt werden, dass die dominierenden Reputationseffekte wohl in der eingeschr{\"a}nkten Wichtigkeit der kapitalmarktorientierten Mandanten f{\"u}r den Gesamtumsatz begr{\"u}ndet liegen, welche von bisherigen Studien systematisch {\"u}bersch{\"a}tzt wird. Kapitel 4 richtet den Fokus auf origin{\"a}r nicht-finanzielle Nachhaltigkeitsstrategien und deren Einfluss auf bilanzpolitisches Verhalten. Bisherige Studien betrachten die heterogene Gruppe der Corporate Social Responsibility (CSR) Unternehmen dabei {\"u}berwiegend in ihrer Gesamtheit. Die vorliegende Analyse in Kapitel 4 versucht demgegen{\"u}ber die untersuchten Unternehmen in pr{\"a}valente Anreizgruppen zu trennen, um vermutete diverse Anreize zur Investition in CSR mit den Anreizen zu Bilanzpolitik in Verbindung zu bringen. Hierf{\"u}r wird ein europ{\"a}isches Setting mit kapitalmarktorientierten Unternehmen der ASSET4 Datenbank zwischen 2005 und 2014 gew{\"a}hlt. Durch eine gezielte Verkn{\"u}pfung der Anreize zur Investition mit der Entscheidung zur einschl{\"a}gigen Berichterstattung werden Unternehmen mit pr{\"a}valenten Reputationsanreizen von Unternehmen mit Tendenzen zur intrinsischen, philanthropischen Motivation abgegrenzt. Die Ergebnisse lassen vermuten, dass Unternehmen mit Reputationsanreizen bilanzpolitisch konform handeln und buchm{\"a}ßige durch reale Bilanzpolitik zu ersetzen versuchen. Hierdurch lassen sich sowohl Risiken der medialen Bilanzschelte minimieren als auch hohe Gewinne als Teil einer Gesamtreputationsstrategie realisieren. Des Weiteren kann gezeigt werden, dass diese strategische Positionierung einen Einfluss auf die Wirkungsweise von Corporate Governance (CG) hat. W{\"a}hrend Maße f{\"u}r gute CG mit einem geringeren Ausmaß an buchm{\"a}ßiger Bilanzpolitik einhergehen, w{\"a}hlen Unternehmen mit Reputationsanreizen koh{\"a}rent mit ihrer strategischen Tendenz erneut ein h{\"o}heres Maß an realer Bilanzpolitik. Insgesamt deuten die Ergebnisse der Studie daraufhin, dass gewisse Unternehmen CSR als Reputationsinstrument nutzen und sich nicht konform einer nachhaltigen Strategie im Hinblick auf Bilanzpolitik verhalten.}, subject = {Bilanzpolitik}, language = {en} } @phdthesis{Ruecker2019, author = {R{\"u}cker, Christoph}, title = {Development of a prevascularized bone implant}, doi = {10.25972/OPUS-17886}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178869}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The skeletal system forms the mechanical structure of the body and consists of bone, which is hard connective tissue. The tasks the skeleton and bones take over are of mechanical, metabolic and synthetic nature. Lastly, bones enable the production of blood cells by housing the bone marrow. Bone has a scarless self-healing capacity to a certain degree. Injuries exceeding this capacity caused by trauma, surgical removal of infected or tumoral bone or as a result from treatment-related osteonecrosis, will not heal. Critical size bone defects that will not heal by themselves are still object of comprehensive clinical investigation. The conventional treatments often result in therapies including burdening methods as for example the harvesting of autologous bone material. The aim of this thesis was the creation of a prevascularized bone implant employing minimally invasive methods in order to minimize inconvenience for patients and surgical site morbidity. The basis for the implant was a decellularized, naturally derived vascular scaffold (BioVaSc-TERM®) providing functional vessel structures after reseeding with autologous endothelial cells. The bone compartment was built by the combination of the aforementioned scaffold with synthetic β-tricalcium phosphate. In vitro culture for tissue maturation was performed using bioreactor technology before the testing of the regenerative potential of the implant in large animal experiments in sheep. A tibia defect was treated without the anastomosis of the implant's innate vasculature to the host's circulatory system and in a second study, with anastomosis of the vessel system in a mandibular defect. While the non-anastomosed implant revealed a mostly osteoconductive effect, the implants that were anastomosed achieved formation of bony islands evenly distributed over the defect. In order to prepare preconditions for a rapid approval of an implant making use of this vascularization strategy, the manufacturing of the BioVaSc-TERM® as vascularizing scaffold was adjusted to GMP requirements.}, subject = {Tissue Engineering}, language = {en} } @phdthesis{Kirilmaz2019, author = {Kirilmaz, Ozan Seyitali}, title = {Thin Film Growth and Characterization of the Transition Metal Oxides Magnetite and Layered Perovskite Iridates}, doi = {10.25972/OPUS-17891}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178917}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {This thesis describes the growth and characterization of both the all-oxide heterostructure Fe3O4/ZnO and the spin-orbit coupling driven layered perovskite iridates. As for Fe3O4/ZnO, the 100\% spin-polarized Fe3O4 is a promising spin electrode candidate for spintronic devices. However, the single crystalline ZnO substrates exhibit different polar surface termination which, together with substrate preparation method, can drastically affect the physical properties of Fe3O4/ZnO heterostructures. In this thesis two different methods of substrate preparation were investigated: a previously used in situ method involving sputtering and annealing treatments and a recent ex situ method containing only the annealing procedure. For the latter, the annealing treatment was performed in dry and humid O2 gas flow for the O- and Zn-terminated substrates, respectively, to produce atomically at surfaces as verified by atomic force microscopy(AFM). With these methods, four different ZnO substrates were fabricated and used further for Fe3O4 film growth. Fe3O4 films of 20 nm thickness were successfully grown by reactive molecular beam epitaxy. AFM measurements reveal a higher film surface roughness for the samples with in situ prepared substrates. Moreover, X-ray photoelectron spectroscopy (XPS) measurements indicate significant Zn substitution within the Fe3O4 film for these samples, whereas the samples with ex situ prepared substrates show stoichiometric Fe3O4 films. X-ray diffraction measurements confirm the observations from XPS, revealing additional peaks due to Zn substitution in Fe3O4 films grown on in situ prepared ZnO substrates. Conductivity, as well as magnetometry, measurements show the presence of Zn-doped ferrites in films grown on in situ prepared substrates. Such unintentionally intercalated Zn-doped ferrites dramatically change the electrical and magnetic properties of the films and, therefore, are not preferred in a high-quality heterostructure. X-ray reflectivity (XRR) measurements show for the film grown on ex situ prepared Zn-terminated substrate a variation of film density close to the interface which is also confirmed by transmission electron microscopy (TEM). Using polarized neutron reflectometry, magnetic depth profiles of the films grown on ex situ prepared substrates clearly indicate Fe3O4 layers with reduced magnetization at the interfaces. This result is consistent with earlier observations made by resonant magnetic X-ray reflectometry (RMXR), but in contrast to the findings from XRR and TEM of this thesis. A detailed TEM study of all four samples shows that the sample with ex situ prepared O-terminated substrate has the sharpest interface, whereas those with ex situ prepared Zn-terminated as well as in situ prepared substrates indicate rougher interfaces. STEM-EELS composition profiles of the samples reveal the Zn substitution in the films with in situ prepared substrates and therefore confirm the presence of Zn-doped ferrites. Moreover, a change of the Fe oxidation state of the first Fe layer at the interface which was observed in previous studies done by RMXR, was not verified for the samples with in situ prepared substrates thus leaving the question of a possible presence of the magnetically dead layer open. Furthermore, density functional theory calculations were performed to determine the termination dependent layer sequences which are ...-Zn-O-(interface)-[Fe(octa)-O-Fe(tetra)-Fe(octa)-Fe(tetra)-O]-[...]-... and ...-O-Zn-(interface)-[O-Fe(octa)-O-Fe(tetra)-Fe(octa)-Fe(tetra)]-[...]-... for the samples with O- and Zn-terminated substrates, respectively. Spin density calculations show that in case of O-termination the topmost substrate layers imitate the spin polarization of film layers close to the interface. Here, the first O layer is affected much stronger than the first Zn layer. Due to the strong decrease of this effect toward deeper substrate layers, the substrate surface is supposed to be sensitive to the contiguous spin polarization of the film. Thus, the topmost O layer of the O-terminated substrate could play the most essential role for effective spin injection into ZnO. The 5d transition metal oxides Ba2IrO4 (BIO) and Sr2IrO4 (SIO) are associated with the Ruddlesden-Popper iridate series with phase type "214" (RP{214), and due to the strong spin-orbit coupling belong to the class of Mott insulators. Moreover, they show many similarities of the isostructural high Tc-cuprate superconductors, e.g. crystal structure, magnetism and electronic band structure. Therefore, it is of great interest to activate a potential superconducting phase in (RP{214) iridates. However, only a small number of publications on PLD grown (RP{214) iridates in the literature exists. Furthermore, published data of soft X-ray angle resolved photoemission spectroscopy (SX-ARPES) experiments mainly originate from measurements which were performed on single crystals or MBE grown films of SIO and BIO. In this thesis La-doped SIO films (La0:2Sr1:8IrO4, further referred as LSIO) were used to pursue a potential superconducting phase. A set of characterization methods was used to analyze the quality of the PLD grown BIO, SIO and LSIO films. AFM measurements demonstrate that thick PLD grown(RP{214) iridate films have rougher surfaces, indicating a transition from a 2D layer-bylayer growth (which is demonstrated by RHEED oscillations) to a 3D island-like growth mode. In addition, chemical depth profiling XPS measurements indicate an increase of the O and Ir relative concentrations in the topmost film layers. Constant energy k-space maps and energy distribution curves (EDCs) measured by SX-ARPES show for every grown film only weak energy band dispersions, which are in strong contrast to the results obtained on the MBE grown films and single crystals from the literature. In this thesis, a subsequent TEM study reveals missing SrO layers within the grown films which occur mainly in the topmost layers, confirming the results and suggestions from XPS and SX-ARPES data: the PLD grown films have defects and, therefore, incoherently scatter photoelectrons. Nevertheless, the LSIO film shows small additional spectral weight between the highsymmetry M points close to the Fermi level which can be attributed to quasiparticle states which, in turn, indicates the formation of a Fermi-arc. However, neither conductivity measurements nor valence band analysis via XPS confirm an activation of a superconducting phase or presence of spectral weight of quasiparticle states at the Fermi level in this LSIO film. It is possible that these discovered difficulties in growth are responsible for the low number of SX-ARPES publications on PLD grown (RP{214) iridate films. For further investigations of (RP{214) iridate films by SX-ARPES, their PLD growth recipes have to be improved to create high quality single crystalline films without imperfections.}, subject = {Magnetit}, language = {en} } @unpublished{MuessigThalerDewhurstetal.2019, author = {Muessig, Jonas H. and Thaler, Melanie and Dewhurst, Rian D. and Paprocki, Valerie and Seufert, Jens and Mattock, James D. and Vargas, Alfredo and Braunschweig, Holger}, title = {Phosphine-Stabilized Diiododiborenes: Isolable Diborenes with Six Labile Bonds}, series = {Angewandte Chemie, International Edition}, journal = {Angewandte Chemie, International Edition}, doi = {10.1002/anie.201814230}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178608}, year = {2019}, abstract = {The lability of B=B, B-P and B-halide bonds is combined in the syntheses of the first diiododiborenes. In a series of reactivity tests, these diiododiborenes demonstrate cleavage of all six of their central bonds in different ways, leading to products of B=B hydrogenation and dihalogenation as well as halide exchange.}, language = {en} } @phdthesis{Grotemeyer2019, author = {Grotemeyer, Alexander}, title = {Characterisation and application of new optogenetic tools in \(Drosophila\) \(melanogaster\)}, doi = {10.25972/OPUS-17879}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178793}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Since Channelrhodopsins has been described first and introduced successfully in freely moving animals (Nagel et al., 2003 and 2005), tremendous impact has been made in this interesting field of neuroscience. Subsequently, many different optogenetic tools have been described and used to address long-lasting scientific issues. Furthermore, beside the 'classical' Channelrhodopsin-2 (ChR2), basically a cation-selective ion channel, also altered ChR2 descendants, anion selective channels and light-sensitive metabotropic proteins have expanded the optogenetic toolbox. However, in spite of this variety of different tools most researches still pick Channelrhodopsin-2 for their optogenetic approaches due to its well-known kinetics. In this thesis, an improved Channelrhodopsin, Channelrhodopsin2-XXM (ChR2XXM), is described, which might become an useful tool to provide ambitious neuroscientific approaches by dint of its characteristics. Here, ChR2XXM was chosen to investigate the functional consequences of Drosophila larvae lacking latrophilin in their chordotonal organs. Finally, the functionality of GtACR, was checked at the Drosophila NMJ. For a in-depth characterisation, electrophysiology along with behavioural setups was employed. In detail, ChR2XXM was found to have a better cellular expression pattern, high spatiotemporal precision, substantial increased light sensitivity and improved affinity to its chromophore retinal, as compared to ChR2. Employing ChR2XXM, effects of latrophilin (dCIRL) on signal transmission in the chordotonal organ could be clarified with a minimum of side effects, e.g. possible heat response of the chordotonal organ, due to high light sensitivity. Moreover, optogenetic activation of the chordotonal organ, in vivo, led to behavioural changes. Additionally, GtACR1 was found to be effective to inhibit motoneuronal excitation but is accompanied by unexpected side effects. These results demonstrate that further improvement and research of optogenetic tools is highly valuable and required to enable researchers to choose the best fitting optogenetic tool to address their scientific questions.}, subject = {Optogenetik}, language = {en} } @phdthesis{Mehringer2019, author = {Mehringer, Sarah}, title = {Essays on Intergenerational Income Mobility in Germany and the United States}, doi = {10.25972/OPUS-16069}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-160693}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {This dissertation consists of three contributions. Each addresses one specific aspect of intergenerational income mobility and is intended to be a stand-alone analysis. All chapters use comparable data for Germany and the United States to conduct country comparisons. As there are usually a large number of studies available for the United States, this approach is useful for comparing the empirical results to the existing literature. The first part conducts a direct country comparison of the structure and extent of intergenerational income mobility in Germany and the United States. In line with existing results, the estimated intergenerational income mobility of 0.49 in the United States is significantly higher than that of 0.31 in Germany. While the results for the intergenerational rank mobility are relatively similar, the level of intergenerational income share mobility is higher in the United States than in Germany. There are no significant indications of a nonlinear run of intergenerational income elasticity. A final decomposition of intergenerational income inequality shows both greater income mobility and stronger progressive income growth for Germany compared to the United States. Overall, no clear ranking of the two countries can be identified. To conclude, several economic policy recommendations to increase intergenerational income mobility in Germany are discussed. The second part examines the transmission channels of intergenerational income persistence in Germany and the United States. In principle, there are two ways in which well-off families may influence the adult incomes of their children: first through direct investments in their children's human capital (investment effect ), and second through the indirect transmission of human capital from parents to children (endowment effect ). In order to disentangle these two effects, a descriptive as well as a structural decomposition method are utilized. The results suggest that the investment effect and the endowment effect each account for approximately half of the estimated intergenerational income elasticity in Germany, while the investment effect is substantially more influential in the United States with a share of around 70 percent. With regard to economic policy, these results imply that equality of opportunity for children born to poor parents cannot be reached by the supply of financial means alone. Conversely, an efficient policy must additionally substitute for the missing direct transmission of human capital within socio-economically weak families. The third part explicitly focuses on the intergenerational income mobility among daughters. The restriction to men is commonly made in the empirical literature due to women's lower labor market participation. While most men work full-time, the majority of (married) women still work only part-time or not at all. Especially with the occurrence of assortative mating, daughters from well-off families are likely to marry rich men and might decide to reduce their labor supply as a result. Thus, the individual labor income of a daughter might not be a good indicator for her actual economic status. The baseline regression analysis shows a higher intergenerational income elasticity in Germany and a lower intergenerational income elasticity in the United States for women as compared to men. However, a separation by marital status reveals that in both countries unmarried women exhibit a higher intergenerational income elasticity than unmarried men, while married women feature a lower intergenerational income elasticity than married men. The reason for the lower mobility of unmarried women turns out to be a stronger human capital transmission from fathers to daughters than to sons. The higher mobility of married women is driven by a weaker human capital transmission and a higher labor supply elasticity with respect to spousal income for women as compared to men. In order to further study the effects of assortative mating, the subsample of married children is analyzed by different types of income. It shows that the estimated intergenerational income elasticity of children's household incomes is even higher than that of their individual incomes. This can be seen as an indication for strong assortative mating. If household income is interpreted as a measure of children's actual economic welfare, there are barely any differences between sons and daughters. The intergenerational income elasticity of spousal income with respect to parental income is again relatively high, which in turn supports the hypothesis of strong assortative mating. The elasticity of the sons-in-law with respect to their fathers-in-law in Germany is even higher than that of the sons with respect to their own fathers.}, subject = {Deutschland}, language = {en} } @phdthesis{Schmithausen2019, author = {Schmithausen, Patrick Alexander Gerhard}, title = {Three-dimensional fluorescence image analysis of megakaryocytes and vascular structures in intact bone}, doi = {10.25972/OPUS-17854}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178541}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The thesis provides insights in reconstruction and analysis pipelines for processing of three-dimensional cell and vessel images of megakaryopoiesis in intact murine bone. The images were captured in a Light Sheet Fluorescence Microscope. The work presented here is part of Collaborative Research Centre (CRC) 688 (project B07) of the University of W{\"u}rzburg, performed at the Rudolf-Virchow Center. Despite ongoing research within the field of megakaryopoiesis, its spatio-temporal pattern of megakaryopoiesis is largely unknown. Deeper insight to this field is highly desirable to promote development of new therapeutic strategies for conditions related to thrombocytopathy as well as thrombocytopenia. The current concept of megakaryopoiesis is largely based on data from cryosectioning or in vitro studies indicating the existence of spatial niches within the bone marrow where specific stages of megakaryopoiesis take place. Since classic imaging of bone sections is typically limited to selective two-dimensional views and prone to cutting artefacts, imaging of intact murine bone is highly desired. However, this has its own challenges to meet, particularly in image reconstruction. Here, I worked on processing pipelines to account for irregular specimen staining or attenuation as well as the extreme heterogeneity of megakaryocyte morphology. Specific challenges for imaging and image reconstruction are tackled and solution strategies as well as remaining limitations are presented and discussed. Fortunately, modern image processing and segmentation strongly benefits from continuous advances in hardware as well as software-development. This thesis exemplifies how a combined effort in biomedicine, computer vision, data processing and image technology leads to deeper understanding of megakaryopoiesis. Tailored imaging pipelines significantly helped elucidating that the large megakaryocytes are broadly distributed throughout the bone marrow facing a surprisingly dense vessel network. No evidence was found for spatial niches in the bone marrow, eventually resulting in a revised model of megakaryopoiesis.}, subject = {Megakaryozytopoese}, language = {en} } @phdthesis{Niebler2019, author = {Niebler, Thomas}, title = {Extracting and Learning Semantics from Social Web Data}, doi = {10.25972/OPUS-17866}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178666}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Making machines understand natural language is a dream of mankind that existed since a very long time. Early attempts at programming machines to converse with humans in a supposedly intelligent way with humans relied on phrase lists and simple keyword matching. However, such approaches cannot provide semantically adequate answers, as they do not consider the specific meaning of the conversation. Thus, if we want to enable machines to actually understand language, we need to be able to access semantically relevant background knowledge. For this, it is possible to query so-called ontologies, which are large networks containing knowledge about real-world entities and their semantic relations. However, creating such ontologies is a tedious task, as often extensive expert knowledge is required. Thus, we need to find ways to automatically construct and update ontologies that fit human intuition of semantics and semantic relations. More specifically, we need to determine semantic entities and find relations between them. While this is usually done on large corpora of unstructured text, previous work has shown that we can at least facilitate the first issue of extracting entities by considering special data such as tagging data or human navigational paths. Here, we do not need to detect the actual semantic entities, as they are already provided because of the way those data are collected. Thus we can mainly focus on the problem of assessing the degree of semantic relatedness between tags or web pages. However, there exist several issues which need to be overcome, if we want to approximate human intuition of semantic relatedness. For this, it is necessary to represent words and concepts in a way that allows easy and highly precise semantic characterization. This also largely depends on the quality of data from which these representations are constructed. In this thesis, we extract semantic information from both tagging data created by users of social tagging systems and human navigation data in different semantic-driven social web systems. Our main goal is to construct high quality and robust vector representations of words which can the be used to measure the relatedness of semantic concepts. First, we show that navigation in the social media systems Wikipedia and BibSonomy is driven by a semantic component. After this, we discuss and extend methods to model the semantic information in tagging data as low-dimensional vectors. Furthermore, we show that tagging pragmatics influences different facets of tagging semantics. We then investigate the usefulness of human navigational paths in several different settings on Wikipedia and BibSonomy for measuring semantic relatedness. Finally, we propose a metric-learning based algorithm in adapt pre-trained word embeddings to datasets containing human judgment of semantic relatedness. This work contributes to the field of studying semantic relatedness between words by proposing methods to extract semantic relatedness from web navigation, learn highquality and low-dimensional word representations from tagging data, and to learn semantic relatedness from any kind of vector representation by exploiting human feedback. Applications first and foremest lie in ontology learning for the Semantic Web, but also semantic search or query expansion.}, subject = {Semantik}, language = {en} } @phdthesis{Kress2019, author = {Kreß, Sebastian}, title = {Development and proof of concept of a biological vascularized cell-based drug delivery system}, doi = {10.25972/OPUS-17865}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178650}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {A major therapeutic challenge is the increasing incidence of chronic disorders. The persistent impairment or loss of tissue function requires constitutive on-demand drug availability optimally achieved by a drug delivery system ideally directly connected to the blood circulation of the patient. However, despite the efforts and achievements in cell-based therapies and the generation of complex and customized cell-specific microenvironments, the generation of functional tissue is still unaccomplished. This study demonstrates the capability to generate a vascularized platform technology to potentially overcome the supply restraints for graft development and clinical application with immediate anastomosis to the blood circulation. The ability to decellularize segments of the rat intestine while preserving the ECM for subsequent reendothelialization was proven. The reestablishment of a functional arteriovenous perfusion circuit enabled the supply of co-cultured cells capable to replace the function of damaged tissue or to serve as a drug delivery system. During in vitro studies, the applicability of the developed miniaturized biological vascularized scaffold (mBioVaSc-TERM®) was demonstrated. While indicating promising results in short term in vivo studies, long term implantations revealed current limitations for the translation into clinical application. The gained insights will impact further improvements of quality and performance of this promising platform technology for future regenerative therapies.}, subject = {Vaskularisation}, language = {en} } @misc{Breitenbach2019, author = {Breitenbach, Tim}, title = {Codes of examples for SQH method}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178588}, year = {2019}, abstract = {Code examples for the paper "On the SQH Scheme to Solve Nonsmooth PDE Optimal Control Problems" by Tim Breitenbach and Alfio Borz{\`i} published in the journal "Numerical Functional Analysis and Optimization", in 2019, DOI: 10.1080/01630563.2019.1599911}, language = {en} } @unpublished{SuessWehnerDostaletal.2019, author = {S{\"u}ß, Jasmin and Wehner, Johannes G. and Dost{\´a}l, Jakub and Engel, Volker and Brixner, Tobias}, title = {Mapping of exciton-exciton annihilation in a molecular dimer via fifth-order femtosecond two-dimensional spectroscopy}, series = {Journal of Physical Chemistry Letters}, journal = {Journal of Physical Chemistry Letters}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178482}, year = {2019}, abstract = {We present a theoretical study on exciton-exciton annihilation (EEA) in a molecular dimer. This process is monitored using a fifth-order coherent two-dimensional (2D) spectroscopy as was recently proposed by Dost{\´a}l et al. [Nat. Commun. 9, 2466 (2018)]. Using an electronic three-level system for each monomer, we analyze the different paths which contribute to the 2D spectrum. The spectrum is determined by two entangled relaxation processes, namely, the EEA and the direct relaxation of higher lying excited states. It is shown that the change of the spectrum as a function of a pulse delay can be linked directly to the presence of the EEA process.}, subject = {Exziton}, language = {en} } @phdthesis{Fleischmann2019, author = {Fleischmann, Pauline Nikola}, title = {Starting foraging life: Early calibration and daily use of the navigational system in \(Cataglyphis\) ants}, doi = {10.25972/OPUS-15995}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159951}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Cataglyphis ants are famous for their navigational abilities. They live in hostile habitats where they forage as solitary scavengers covering distances of more than hundred thousand times their body lengths. To return to their nest with a prey item - mainly other dead insects that did not survive the heat - Cataglyphis ants constantly keep track of their directions and distances travelled. The navigational strategy is called path integration, and it enables an ant to return to the nest in a straight line using its home vector. Cataglyphis ants mainly rely on celestial compass cues, like the position of the sun or the UV polarization pattern, to determine directions, and they use an idiothetic step counter and optic flow to measure distances. In addition, they acquire information about visual, olfactory and tactile landmarks, and the wind direction to increase their chances of returning to the nest safe and sound. Cataglyphis' navigational performance becomes even more impressive if one considers their life style. Most time of their lives, the ants stay underground and perform tasks within the colony. When they start their foraging careers outside the nest, they have to calibrate their compass systems and acquire all information necessary for navigation during subsequent foraging. This navigational toolkit is not instantaneously available, but has to be filled with experience. For that reason, Cataglyphis ants perform a striking behavior for up to three days before actually foraging. These so-called learning walks are crucial for the success as foragers later on. In the present thesis, both the ontogeny and the fine-structure of learning walks has been investigated. Here I show with displacement experiments that Cataglyphis ants need enough space and enough time to perform learning walks. Spatially restricted novices, i. e. na{\"i}ve ants, could not find back to the nest when tested as foragers later on. Furthermore, ants have to perform several learning walks over 1-3 days to gain landmark information for successful homing as foragers. An increasing number of feeder visits also increases the importance of landmark information, whereas in the beginning ants fully rely on their path-integration vector. Learning walks are well-structured. High-speed video analysis revealed that Cataglyphis ants include species-specific rotational elements in their learning walks. Greek Cataglyphis ants (C. noda and C. aenescens) inhabiting a cluttered pine forest perform voltes, small walked circles, and pirouettes, tight turns about the body axis with frequent stopping phases. During the longest stopping phases, the ants gaze back to their nest entrance. The Tunisian Cataglyphis fortis ants inhabiting featureless saltpans only perform voltes without directed gazes. The function of voltes has not yet been revealed. In contrast, the fine structure of pirouettes suggests that the ants take snapshots of the panorama towards their homing direction to memorize the nest's surroundings. The most likely hypothesis was that Cataglyphis ants align the gaze directions using their path integrator, which gets directional input from celestial cues during foraging. To test this hypothesis, a manipulation experiment was performed changing the celestial cues above the nest entrance (no sun, no natural polarization pattern, no UV light). The accurately directed gazes to the nest entrance offer an easily quantifiable readout suitable to ask the ants where they expect their nest entrance. Unexpectedly, all novices performing learning walks under artificial sky conditions looked back to the nest entrance. This was especially surprising, because neuronal changes in the mushroom bodies and the central complex receiving visual input could only be induced with the natural sky when comparing test animals with interior workers. The behavioral findings indicated that Cataglyphis ants use another directional reference system to align their gaze directions during the longest stopping phases of learning walk pirouettes. One possibility was the earth's magnetic field. Indeed, already disarraying the geomagnetic field at the nest entrance with an electromagnetic flat coil indicated that the ants use magnetic information to align their looks back to the nest entrance. To investigate this finding further, ants were confronted with a controlled magnetic field using a Helmholtz coil. Elimination of the horizontal field component led to undirected gaze directions like the disarray did. Rotating the magnetic field about 90°, 180° or -90° shifted the ants' gaze directions in a predictable manner. Therefore, the earth's magnetic field is a necessary and sufficient reference system for aligning nest-centered gazes during learning-walk pirouettes. Whether it is additionally used for other navigational purposes, e. g. for calibrating the solar ephemeris, remains to be tested. Maybe the voltes performed by all Cataglyphis ant species investigated so far can help to answer this question..}, subject = {Cataglyphis}, language = {en} } @phdthesis{vonKistowski2019, author = {von Kistowski, J{\´o}akim Gunnarsson}, title = {Measuring, Rating, and Predicting the Energy Efficiency of Servers}, doi = {10.25972/OPUS-17847}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178478}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Energy efficiency of computing systems has become an increasingly important issue over the last decades. In 2015, data centers were responsible for 2\% of the world's greenhouse gas emissions, which is roughly the same as the amount produced by air travel. In addition to these environmental concerns, power consumption of servers in data centers results in significant operating costs, which increase by at least 10\% each year. To address this challenge, the U.S. EPA and other government agencies are considering the use of novel measurement methods in order to label the energy efficiency of servers. The energy efficiency and power consumption of a server is subject to a great number of factors, including, but not limited to, hardware, software stack, workload, and load level. This huge number of influencing factors makes measuring and rating of energy efficiency challenging. It also makes it difficult to find an energy-efficient server for a specific use-case. Among others, server provisioners, operators, and regulators would profit from information on the servers in question and on the factors that affect those servers' power consumption and efficiency. However, we see a lack of measurement methods and metrics for energy efficiency of the systems under consideration. Even assuming that a measurement methodology existed, making decisions based on its results would be challenging. Power prediction methods that make use of these results would aid in decision making. They would enable potential server customers to make better purchasing decisions and help operators predict the effects of potential reconfigurations. Existing energy efficiency benchmarks cannot fully address these challenges, as they only measure single applications at limited sets of load levels. In addition, existing efficiency metrics are not helpful in this context, as they are usually a variation of the simple performance per power ratio, which is only applicable to single workloads at a single load level. Existing data center efficiency metrics, on the other hand, express the efficiency of the data center space and power infrastructure, not focusing on the efficiency of the servers themselves. Power prediction methods for not-yet-available systems that could make use of the results provided by a comprehensive power rating methodology are also lacking. Existing power prediction models for hardware designers have a very fine level of granularity and detail that would not be useful for data center operators. This thesis presents a measurement and rating methodology for energy efficiency of servers and an energy efficiency metric to be applied to the results of this methodology. We also design workloads, load intensity and distribution models, and mechanisms that can be used for energy efficiency testing. Based on this, we present power prediction mechanisms and models that utilize our measurement methodology and its results for power prediction. Specifically, the six major contributions of this thesis are: We present a measurement methodology and metrics for energy efficiency rating of servers that use multiple, specifically chosen workloads at different load levels for a full system characterization. We evaluate the methodology and metric with regard to their reproducibility, fairness, and relevance. We investigate the power and performance variations of test results and show fairness of the metric through a mathematical proof and a correlation analysis on a set of 385 servers. We evaluate the metric's relevance by showing the relationships that can be established between metric results and third-party applications. We create models and extraction mechanisms for load profiles that vary over time, as well as load distribution mechanisms and policies. The models are designed to be used to define arbitrary dynamic load intensity profiles that can be leveraged for benchmarking purposes. The load distribution mechanisms place workloads on computing resources in a hierarchical manner. Our load intensity models can be extracted in less than 0.2 seconds and our resulting models feature a median modeling error of 12.7\% on average. In addition, our new load distribution strategy can save up to 10.7\% of power consumption on a single server node. We introduce an approach to create small-scale workloads that emulate the power consumption-relevant behavior of large-scale workloads by approximating their CPU performance counter profile, and we introduce TeaStore, a distributed, micro-service-based reference application. TeaStore can be used to evaluate power and performance model accuracy, elasticity of cloud auto-scalers, and the effectiveness of power saving mechanisms for distributed systems. We show that we are capable of emulating the power consumption behavior of realistic workloads with a mean deviation less than 10\% and down to 0.2 watts (1\%). We demonstrate the use of TeaStore in the context of performance model extraction and cloud auto-scaling also showing that it may generate workloads with different effects on the power consumption of the system under consideration. We present a method for automated selection of interpolation strategies for performance and power characterization. We also introduce a configuration approach for polynomial interpolation functions of varying degrees that improves prediction accuracy for system power consumption for a given system utilization. We show that, in comparison to regression, our automated interpolation method selection and configuration approach improves modeling accuracy by 43.6\% if additional reference data is available and by 31.4\% if it is not. We present an approach for explicit modeling of the impact a virtualized environment has on power consumption and a method to predict the power consumption of a software application. Both methods use results produced by our measurement methodology to predict the respective power consumption for servers that are otherwise not available to the person making the prediction. Our methods are able to predict power consumption reliably for multiple hypervisor configurations and for the target application workloads. Application workload power prediction features a mean average absolute percentage error of 9.5\%. Finally, we propose an end-to-end modeling approach for predicting the power consumption of component placements at run-time. The model can also be used to predict the power consumption at load levels that have not yet been observed on the running system. We show that we can predict the power consumption of two different distributed web applications with a mean absolute percentage error of 2.2\%. In addition, we can predict the power consumption of a system at a previously unobserved load level and component distribution with an error of 1.2\%. The contributions of this thesis already show a significant impact in science and industry. The presented efficiency rating methodology, including its metric, have been adopted by the U.S. EPA in the latest version of the ENERGY STAR Computer Server program. They are also being considered by additional regulatory agencies, including the EU Commission and the China National Institute of Standardization. In addition, the methodology's implementation and the underlying methodology itself have already found use in several research publications. Regarding future work, we see a need for new workloads targeting specialized server hardware. At the moment, we are witnessing a shift in execution hardware to specialized machine learning chips, general purpose GPU computing, FPGAs being embedded into compute servers, etc. To ensure that our measurement methodology remains relevant, workloads covering these areas are required. Similarly, power prediction models must be extended to cover these new scenarios.}, subject = {Benchmarking}, language = {en} } @phdthesis{Bangert2019, author = {Bangert, Philip}, title = {Magnetic Attitude Control of Miniature Satellites and its Extension towards Orbit Control using an Electric Propulsion System}, isbn = {978-3-945459-28-7 (online)}, issn = {1868-7474}, doi = {10.25972/OPUS-17702}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177020}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The attitude and orbit control system of pico- and nano-satellites to date is one of the bottle necks for future scientific and commercial applications. A performance increase while keeping with the satellites' restrictions will enable new space missions especially for the smallest of the CubeSat classes. This work addresses methods to measure and improve the satellite's attitude pointing and orbit control performance based on advanced sensor data analysis and optimized on-board software concepts. These methods are applied to spaceborne satellites and future CubeSat missions to demonstrate their validity. An in-orbit calibration procedure for a typical CubeSat attitude sensor suite is developed and applied to the UWE-3 satellite in space. Subsequently, a method to estimate the attitude determination accuracy without the help of an external reference sensor is developed. Using this method, it is shown that the UWE-3 satellite achieves an in-orbit attitude determination accuracy of about 2°. An advanced data analysis of the attitude motion of a miniature satellite is used in order to estimate the main attitude disturbance torque in orbit. It is shown, that the magnetic disturbance is by far the most significant contribution for miniature satellites and a method to estimate the residual magnetic dipole moment of a satellite is developed. Its application to three CubeSats currently in orbit reveals that magnetic disturbances are a common issue for this class of satellites. The dipole moments measured are between 23.1mAm² and 137.2mAm². In order to autonomously estimate and counteract this disturbance in future missions an on-board magnetic dipole estimation algorithm is developed. The autonomous neutralization of such disturbance torques together with the simplification of attitude control for the satellite operator is the focus of a novel on-board attitude control software architecture. It incorporates disturbance torques acting on the satellite and automatically optimizes the control output. Its application is demonstrated in space on board of the UWE-3 satellite through various attitude control experiments of which the results are presented here. The integration of a miniaturized electric propulsion system will enable CubeSats to perform orbit control and, thus, open up new application scenarios. The in-orbit characterization, however, poses the problem of precisely measuring very low thrust levels in the order of µN. A method to measure this thrust based on the attitude dynamics of the satellite is developed and evaluated in simulation. It is shown, that the demonstrator mission UWE-4 will be able to measure these thrust levels with a high accuracy of 1\% for thrust levels higher than 1µN. The orbit control capabilities of UWE-4 using its electric propulsion system are evaluated and a hybrid attitude control system making use of the satellite's magnetorquers and the electric propulsion system is developed. It is based on the flexible attitude control architecture mentioned before and thrust vector pointing accuracies of better than 2° can be achieved. This results in a thrust delivery of more than 99\% of the desired acceleration in the target direction.}, subject = {Satellit}, language = {en} } @phdthesis{Wistlich2019, author = {Wistlich, Laura}, title = {NCO-sP(EO-stat-PO) as functional additive for biomaterials' development}, doi = {10.25972/OPUS-17836}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178365}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The aim of this thesis was the application of the functional prepolymer NCO-sP(EO-stat-PO) for the development of new biomaterials. First, the influence of the star-shaped polymers on the mechanical properties of biocements and bone adhesives was investigated. 3-armed star-shaped macromers were used as an additive for a mineral bone cement, and the influence on the mechanical properties was studied. Additionally, a previously developed bone adhesive was examined regarding cytocompatibility. The second topic was the examination of novel functionalization steps which were performed on the surface of electrospun fibers modified with NCO-sP(EO-stat-PO). This established method of functionalizing electrospun meshes was advanced regarding the modification with proteins which was then demonstrated in a biological application. Two different kinds of antibodies were immobilized on the fiber surface in a consecutive manner and the influence of these proteins on the cell behavior was investigated. The final topic involved the quantification of surface-bound peptide sequences. By functionalization of the peptides with the UV-reactive molecule 2-mercaptopyridine it was possible to quantify this compound via UV measurements by cleavage of disulfide bridges and indirectly draw conclusions about the number of immobilized peptides. In the field of mineral biocements and bone adhesives, NCO-sP(EO-stat-PO) was able to influence the setting behavior and mechanical performance of mineral bone cements based on calcium phosphate chemistry. The addition of NCO-sP(EO-stat-PO) resulted in a pseudo-ductile fracture behavior due to the formation of a hydrogel network in the cement, which was then mineralized by nanosized hydroxyapatite crystals following cement setting. Accordingly, a commercially available aluminum silicate cement from civil engineering could be modified. In addition, it could be shown that the use of NCO-sP(EO-stat-PO) is beneficial for adjusting specific material properties of bone adhesives. Here, the crosslinking behavior of the prepolymer in an aqueous medium was exploited to form an interpenetrating network (IPN) together with a photochemically curing poly(ethylene glycol) dimethacrylate (PEGDMA) matrix. This could be used for the development of a bone adhesive with an improved adhesion to bone in a wet environment. The developed bone adhesive was further investigated in terms of possible influences of the initiator systems. In addition, the material system was tested for cytocompatibility by using different cell lines. Moreover, the preparation of electrospun fiber meshes via solution electrospinning consisting of poly(lactide-co-glycolide) (PLGA) as a backbone polymer and NCO-sP(EO-stat-PO) as functional additive is an established method for the application of the meshes as a replacement of the native extracellular matrix (ECM). In general, these fibers reveal diameters in the nanometer range, are protein and cell repellent due to the hydrophilic properties of the prepolymer and show a specific biofunctionalization by immobilization of peptide sequences. Here, the isocyanate groups presented on the fiber surface after electrospinning were used to carry out various functionalization steps, while retaining the properties of protein and cell repellency. The modification of the electrospun fibers involved the immobilization of analogs or antagonists of tumor necrosis factor (TNF) and the indirect detection of these by interaction with a light-producing enzyme. Here, a multimodal modification of the fiber surface with RGD to mediate cell adhesion and two different antibodies could be achieved. After culturing the cell line HT1080, the pro- or anti-inflammatory response of cells could be detected by IL-8 specific ELISA measurements. Furthermore, the quantification of molecules on the surface of electrospun fibers was investigated. It was tested whether the detection by means of super-resolution microscopy would be possible. Therefore, experiments were performed with short amino acid sequences such as RGD for quantification by fluorescence microscopy. Based on earlier results, in which a UV-spectrometrically active molecule was used to detect the quantification of RGD, it was shown that short peptides can also be quantified in a small scale on flat functional substrates (2D) such as NCO-sP(EO-stat-PO) hydrogel coatings, and modified electrospun fibers produced from PLGA and NCO-sP(EO-stat-PO) (3D). In addition, a collagen sequence was used to prove that a successful quantification can be carried out as well for longer peptide chains. These studies have revealed that NCO-sP(EO-stat-PO) can serve as a functional additive for many applications and should be considered for further studies on the development of novel biomaterials. The rapid crosslinking reaction, the resulting hydrogel formation and the biocompatibility are to be mentioned as positive properties, which makes the prepolymer interesting for future applications.}, subject = {Sternpolymere}, language = {en} } @phdthesis{Kirchner2019, author = {Kirchner, Eva}, title = {Discrete Supramolecular Stacks by Self-Assembly and Folding of Bis(merocyanine) Dyes}, doi = {10.25972/OPUS-15941}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159419}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The present thesis describes the development of a strategy to create discrete finite-sized supramolecular stacks of merocyanine dyes. Thus, bichromophoric stacks of two identical or different chromophores could be realized by folding of bis(merocyanine) dyes and their optical properties were discussed in terms of exciton theory. Quantum chemical calculations revealed strong exciton coupling between the chromophores within the homo- and hetero-π-stacks and the increase of the J-band of the hetero-dimers with increasing energy difference between the excited states of the chromophores could be attributed not only to the different magnitudes of transition dipole moments of the chromophores but also to the increased localization of the excitation in the respective exciton state. Furthermore, careful selection of the length of the spacer unit that defines the interplanar distance between the tethered chromophores directed the self-assembly of the respective bis(merocyanines) into dimers, trimers and tetramers comprising large, structurally precise π-stacks of four, six or eight merocyanine chromophores. It could be demonstrated that the structure of such large supramolecular architectures can be adequately elucidated by commonly accessible analysis tools, in particular NMR techniques in combination with UV/vis measurements and mass spectrometry. Supported by TDDFT calculations, the absorption spectra of the herein investigated aggregates could be explained and a relationship between the absorption properties and the number of stacking chromophores could be established based on exciton theory.}, subject = {Merocyanine}, language = {en} } @phdthesis{Heilos2019, author = {Heilos, Anna}, title = {Mechanistic Insights into the Inhibition of Cathepsin B and Rhodesain with Low-Molecular Inhibitors}, doi = {10.25972/OPUS-17822}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178228}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Cysteine proteases play a crucial role in medical chemistry concerning various fields reaching from more common ailments like cancer and hepatitis to less noted tropical diseases, namely the so-called African Sleeping Sickness (Human Arfican Trypanosomiasis). Detailed knowledge about the catalytic function of these systems is highly desirable for drug research in the respective areas. In this work, the inhibition mechanisms of the two cysteine proteases cathepsin B and rhodesain with respectively one low-molecular inhibitor class were investigated in detail, using computational methods. In order to sufficiently describe macromolecular systems, molecular mechanics based methods (MM) and quantum mechanical based method (QM), as well as hybrid methods (QM/MM) combining those two approaches, were applied. For Cathespin B, carbamate-based molecules were investigated as potential inhibitors for the cysteine protease. The results indicate, that water-bridged proton-transfer reactions play a crucial role for the inhibition. The energetically most favoured pathway (according to the calculations) includes an elimination reaction following an E1cB mechanism with a subsequent carbamylation of the active site amino acid cysteine. Nitroalkene derivatives were investigated as inhibitors for rhodesain. The investigation of structurally similar inhibitors showed, that even small steric differences can crucially influence the inhibition potential of the components. Furthermore, the impact of a fluorination of the nitroalkene inhibitors on the inhibition mechanism was investigated. According to experimental data measured from the working group of professor Schirmeister in Mainz, fluorinated nitroalkenes show - in contrast to the unfluorinated compounds - a time dependent inhibition efficiency. The calculations of the systems indicate, that the fluorination impacts the non-covalent interactions of the inhibitors with the enzymatic environment of the enzyme which results in a different inhibition behaviour.}, subject = {Cysteinproteasen}, language = {en} } @phdthesis{Herget2019, author = {Herget, Verena}, title = {A novel approach for the calibration of the hadronic recoil for the measurement of the mass of the W boson with the ATLAS Experiment}, doi = {10.25972/OPUS-17782}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177828}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The measurement of the mass of the \$W\$ boson is currently one of the most promising precision analyses of the Standard Model, that could ultimately reveal a hint for new physics. The mass of the \$W\$ boson is determined by comparing the \$W\$ boson, which cannot be reconstructed directly, to the \$Z\$ boson, where the full decay signature is available. With the help of Monte Carlo simulations one can extrapolate from the \$Z\$ boson to the \$W\$ boson. Technically speaking, the measurement of the \$W\$ boson mass is performed by comparing data taken by the ATLAS experiment to a set of calibrated Monte Carlo simulations, which reflect different mass hypotheses.\ A dedicated calibration of the reconstructed objects in the simulations is crucial for a high precision of the measured value. The comparison of simulated \$Z\$ boson events to reconstructed \$Z\$ boson candidates in data allows to derive event weights and scale factors for the calibration. This thesis presents a new approach to reweight the hadronic recoil in the simulations. The focus of the calibration is on the average hadronic activity visible in the mean of the scalar sum of the hadronic recoil \$\Sigma E_T\$ as a function of pileup. In contrast to the standard method, which directly reweights the scalar sum, the dependency to the transverse boson momentum is less strongly affected here. The \$\Sigma E_T\$ distribution is modeled first by means of its pileup dependency. Then, the remaining differences in the resolution of the vector sum of the hadronic recoil are scaled. This is done separately for the parallel and the pterpendicular component of the hadronic recoil with respect to the reconstructed boson. This calibration was developed for the dataset taken by the ATLAS experiment at a center of mass energy of \$8\,\textrm{TeV}\$ in 2012. In addition, the same reweighting procedure is applied to the recent dataset with a low pileup contribution, the \textit{lowMu} runs at \$5\,\textrm{TeV}\$ and at \$13\,\textrm{TeV}\$, taken by ATLAS in November 2017. The dedicated aspects of the reweighting procedure are presented in this thesis. It can be shown that this reweighting approach improves the agreement between data and the simulations effectively for all datasets. The uncertainties of this reweighting approach as well as the statistical errors are evaluated for a \$W\$ mass measurement by a template fit to pseudodata for the \textit{lowMu} dataset. A first estimate of these uncertainties is given here. For the pfoEM algorithm a statistical uncertainty of \$17\,\text{MeV}\$ for the \$5\,\textrm{TeV}\$ dataset and of \$18\,\text{MeV}\$ for the \$13\,\textrm{TeV}\$ are found for the \$W \rightarrow \mu \nu\$ analysis. The systematic uncertainty introduced by the resolution scaling has the largest effect, a value of \$15\,\text{MeV}\$ is estimated for the \$13\,\textrm{TeV}\$ dataset in the muon channel.}, subject = {Standardmodell }, language = {en} } @phdthesis{Weinhard2019, author = {Weinhard, Alexander}, title = {Managing RFID Implementations - Implications for Managerial Decision Making}, doi = {10.25972/OPUS-17816}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-178161}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The present dissertation investigates the management of RFID implementations in retail trade. Our work contributes to this by investigating important aspects that have so far received little attention in scientific literature. We therefore perform three studies about three important aspects of managing RFID implementations. We evaluate in our first study customer acceptance of pervasive retail systems using privacy calculus theory. The results of our study reveal the most important aspects a retailer has to consider when implementing pervasive retail systems. In our second study we analyze RFID-enabled robotic inventory taking with the help of a simulation model. The results show that retailers should implement robotic inventory taking if the accuracy rates of the robots are as high as the robots' manufacturers claim. In our third and last study we evaluate the potentials of RFID data for supporting managerial decision making. We propose three novel methods in order to extract useful information from RFID data and propose a generic information extraction process. Our work is geared towards practitioners who want to improve their RFID-enabled processes and towards scientists conducting RFID-based research.}, subject = {RFID}, language = {en} } @phdthesis{Rieger2019, author = {Rieger, Max}, title = {Preconcentration with Metal-Organic Frameworks as adsorbents for airborne Explosives and Hazardous Materials - A study using inverse gas chromatography}, doi = {10.25972/OPUS-17775}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177750}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Sensitivity and selectivity remain the central technical requirement for analytical devices, detectors and sensors. Especially in the gas phase, concentrations of threat substances can be very low (e.g. explosives) or have severe effects on health even at low concentrations (e.g. benzene) while it contains many potential interferents. Preconcentration, facilitated by active or passive sampling of air by an adsorbent, followed by thermal desorption, results in these substances being released in a smaller volume, effectively increasing their concentration. Traditionally, a wide range of adsorbents, such as active carbons or porous polymers, are used for preconcentration. However, many adsorbents either show chemical reactions due to active surfaces, serious water retention or high background emission due to thermal instability. Metal-organic frameworks (MOFs) are a hybrid substance class, composed inorganic and organic building blocks, being a special case of coordination polymers containing pores. They can be tailored for specific applications such as gas storage, separation, catalysis, sensors or drug delivery. This thesis is focused on investigating MOFs for their use in thermal preconcentration for airborne detection systems. A pre-screening method for MOF-adsorbate interactions was developed and applied, namely inverse gas chromatography (iGC). Using this pulse chromatographic method, the interaction of MOFs and molecules from the class of explosives and volatile organic compounds was studied at different temperatures and compared to thermal desorption results. In the first part, it is shown that archetype MOFs (HKUST-1, MIL-53 and Fe-BTC) outperformed the state-of-the-art polymeric adsorbent Tenax® TA in nitromethane preconcentration for a 1000 (later 1) ppm nitromethane source. For HKUST-1, a factor of more than 2000 per g of adsorbent was achieved, about 100 times higher than for Tenax. Thereby, a nitromethane concentration of 1 ppb could be increased to 2 ppm. High enrichment is addressed to the specific interaction of the nitro group as by iGC, which was determined by comparing nitromethane's free enthalpy of adsorption with the respective saturated alkane. Also, HKUST-1 shows a similar mode of sorption (enthalpy-entropy compensation) for nitro and saturated alkanes. In the second part, benzene of 1 ppm of concentration was enriched with a similar setup, using 2nd generation MOFs, primarily UiO-66 and UiO-67, under dry and humid (50 \%rH) conditions using constant sampling times. Not any MOF within the study did surpass the polymeric Tenax in benzene preconcentration. This is most certainly due to low sampling times - while Tenax may be highly saturated after 600 s, MOFs are not. For regular UiO-66, four differently synthesized samples showed a strongly varying behavior for dry and humid enrichment which cannot be completely explained. iGC investigations with regular alkanes and BTEX compounds revealed that confinement factors and dispersive surface energy were different for all UiO-66 samples. Using physicochemical parameters from iGC, no unified hypothesis explaining all variances could be developed. Altogether, it was shown that MOFs can replace or add to state-of-the-art adsorbents for the enrichment of specific analytes with preconcentration being a universal sensitivity-boosting concept for detectors and sensors. Especially with iGC as a powerful screening tool, most suitable MOFs for the respective target analyte can be evaluated. iGC can be used for determining "single point" retention volumes, which translate into partition coefficients for a specific MOF × analyte × temperature combination.}, subject = {Metallorganisches Netzwerk}, language = {en} } @incollection{MiddelhoffSchoenbeck2019, author = {Middelhoff, Frederike and Sch{\"o}nbeck, Sebastian}, title = {Coming to Terms: The Poetics of More-than-human Worlds}, series = {Texts, Animals, Environments: Zoopoetics and Ecopoetics}, booktitle = {Texts, Animals, Environments: Zoopoetics and Ecopoetics}, publisher = {Rombach Druck- und Verlagshaus}, address = {Freiburg i. Br.}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177783}, publisher = {Universit{\"a}t W{\"u}rzburg}, pages = {11-38}, year = {2019}, abstract = {No abstract available.}, language = {en} } @phdthesis{Pohl2019, author = {Pohl, Daniel}, title = {Universal Locally Univalent Functions and Universal Conformal Metrics}, doi = {10.25972/OPUS-17717}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177174}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The work at hand discusses various universality results for locally univalent and conformal metrics. In Chapter 2 several interesting approximation results are discussed. Runge-type Theorems for holomorphic and meromorphic locally univalent functions are shown. A well-known local approximation theorem for harmonic functions due to Keldysh is generalized to solutions of the curvature equation. In Chapter 3 and 4 these approximation theorems are used to establish universality results for locally univalent functions and conformal metrics. In particular locally univalent analogues for well-known universality results due Birkhoff, Seidel \& Walsh and Heins are shown.}, subject = {Schlichte Funktion}, language = {en} } @phdthesis{Dindas2019, author = {Dindas, Julian}, title = {Cytosolic Ca\(^2\)\(^+\), a master regulator of vacuolar ion conductance and fast auxin signaling in \(Arabidopsis\) \(thaliana\)}, doi = {10.25972/OPUS-15863}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158638}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Das Phytohormon Auxin erf{\"u}llt wichtige Funktionen bei der Initiierung von pflanzlichen Geweben und Organen, wie auch in der Steuerung des Wurzelwachstums im Zusammenspiel mit {\"a}ußeren Reizen wie Schwerkraft, Wasser- und N{\"a}hstoffverf{\"u}gbarkeit. Diese Funktionen basieren dabei vor allem auf der Auxin-abh{\"a}ngigen Regulation von Zellteilung und -streckung. Wichtig f{\"u}r letzteres ist dabei die Kontrolle des Zellturgors durch die Vakuole. Als Speicher f{\"u}r N{\"a}hrstoffe, Metabolite und Toxine sind Vakuolen von essentieller Bedeutung. Vakuol{\"a}r gespeicherte Metabolite und Ionen werden sowohl {\"u}ber aktive Transportprozesse, als auch passiv durch Ionenkan{\"a}le, {\"u}ber die vakuol{\"a}re Membran mit dem Zytoplasma ausgetauscht. In ihrer Funktion als second messenger sind Kalziumionen wichtige Regulatoren, aber auch Gegenstand vakuol{\"a}rer Transportprozesse. {\"A}nderungen der zytosolischen Kalziumkonzentration wirken nicht nur lokal, sie werden auch mit einer Signalweiterleitung {\"u}ber l{\"a}ngere Distanzen in Verbindung gebracht. Im Rahmen dieser Arbeit wurden elektrophysiologische Methoden mit bildgebenden Methoden kombiniert um Einblicke in das Zusammenspiel zwischen zytosolischen Kalziumsignalen, vakuol{\"a}rer Transportprozesse und der Auxin-Physiologie im intakten pflanzlichen Organismus zu gewinnen. Kalziumsignale sind an der Regulierung vakuol{\"a}rer Ionenkan{\"a}le und Transporter beteiligt. Um dies im intakten Organismus zu untersuchen wurden im Modellsystem junger Wurzelhaare von Arabidopsis thaliana Messungen mit intrazellul{\"a}ren Mikroelektroden durchgef{\"u}hrt. Mittels der Zwei-Elektroden-Spannungsklemm-Technik konnte best{\"a}tigt werden, dass die vakuol{\"a}re Membran der limitierende elektrische Wiederstand w{\"a}hrend intravakuol{\"a}rer Messungen ist und so gemessene Ionenstr{\"o}me in der Tat nur die Str{\"o}me {\"u}ber die vakuol{\"a}re Membran repr{\"a}sentieren. Die bereits bekannte zeitabh{\"a}ngige Abnahme der vakuol{\"a}ren Leitf{\"a}higkeit in Einstichexperimenten konnte weiterhin mit einer einstichbedingten, transienten Erh{\"o}hung der zytosolischen Kalziumkonzentration korreliert werden. Durch intravakuol{\"a}re Spannungsklemmexperimente in Wurzelhaarzellen von Kalziumreporterpflanzen konnte dieser Zusammenhang zwischen vakuol{\"a}rer Leitf{\"a}higkeit und der zytosolischen Kalziumkonzentration best{\"a}tigt werden. Die Vakuole ist jedoch nicht nur ein Empf{\"a}nger zytosolischer Kalziumsignale. Da die Vakuole den gr{\"o}ßten intrazellul{\"a}ren Kalziumspeicher darstellt, wird seit Langem diskutiert, ob sie auch an der Erzeugung solcher Signale beteiligt ist. Dies konnte in intakten Wurzelhaarzellen best{\"a}tigt werden. {\"A}nderungen des vakuol{\"a}ren Membranpotentials wirkten sich auf die zytosolische Kalziumkonzentration in diesen Zellen aus. W{\"a}hrend depolarisierende Potentiale zu einer Erh{\"o}hung der zytosolischen Kalziumkonzentration f{\"u}hrten, bewirkte eine Hyperpolarisierung der vakuol{\"a}ren Membran das Gegenteil. Thermodynamische {\"U}berlegungen zum passiven und aktiven Kalziumtransport {\"u}ber die vakuol{\"a}re Membran legten dabei den Schluss nahe, dass die hierin beschriebenen Ergebnisse das Verhalten von vakuol{\"a}ren H+/Ca2+ Austauschern wiederspiegeln, deren Aktivit{\"a}t durch die protonenmotorische Kraft bestimmt wird. Im Rahmen dieser Arbeit stellte sich weiterhin heraus, dass zytosolisches Kalzium ebenso ein zentraler Regulator eines schnellen Auxin-induzierten Signalweges ist, {\"u}ber den der polare Transport des Hormons reguliert wird. Im gleichen Modellsystem junger Wurzelhaare konnte gezeigt werden, dass die externe Applikation von Auxin eine sehr schnelle, Auxinkonzentrations- und pH-abh{\"a}ngige Depolarisation des Plasmamembranpotentials zur Folge hat. Synchron zur Depolarisation des Plasmamembranpotentials wurden im Zytosol transiente Kalziumsignale registriert. Diese wurden durch einen von Auxin aktivierten Einstrom von Kalziumionen durch den Ionenkanal CNGC14 hervorgerufen. Experimente an Verlustmutanten als auch pharmakologische Experimente zeigten, dass zur Auxin-induzierten Aktivierung des Kalziumkanals die Auxin-Perzeption durch die F-box Proteine der TIR1/AFB Familie erforderlich ist. Durch Untersuchungen der Auxin-abh{\"a}ngigen Depolarisation wie auch des Auxin-induzierten Einstroms von Protonen in epidermale Wurzelzellen von Verlustmutanten konnte gezeigt werden, dass die sekund{\"a}r aktive Aufnahme von Auxin durch das hochaffine Transportprotein AUX1 f{\"u}r die schnelle Depolarisation verantwortlich ist. Nicht nur die zytosolischen Kalziumsignale korrelierten mit der CNGC14 Funktion, sondern ebenso die AUX1-vermittelte Depolarisation von Wurzelhaaren. Eine unver{\"a}nderte Expression von AUX1 in der cngc14 Verlustmutante legte dabei den Schluss nahe, dass die Aktivit{\"a}t von AUX1 posttranslational reguliert werden muss. Diese Hypothese erfuhr Unterst{\"u}tzung durch Experimente, in denen die Behandlung mit dem Kalziumkanalblocker Lanthan zu einer Inaktivierung von AUX1 im Wildtyp f{\"u}hrte. Die zytosolische Beladung einzelner epidermaler Wurzelzellen mit Auxin hatte die Ausbreitung lateraler und acropetaler Kalziumwellen zur Folge. Diese korrelierten mit einer Verschiebung des Auxin-Gradienten an der Wurzelspitze und unterst{\"u}tzten somit eine hypothetische Kalziumabh{\"a}ngige Regulation des polaren Auxin Transports. Ein Model f{\"u}r einen schnellen, Auxin induzierten und kalziumabh{\"a}ngigen Signalweg wird pr{\"a}sentiert und dessen Bedeutung f{\"u}r das gravitrope Wurzelwachstum diskutiert. Da die AUX1-vermittelte Depolarisation in Abh{\"a}ngigkeit von der externen Phosphatkonzentration variierte, wird die Bedeutung dieses schnellen Signalwegs ebenso f{\"u}r die Anpassung des Wurzelhaarwachstums an eine nicht ausreichende Verf{\"u}gbarkeit von Phosphat diskutiert.}, subject = {Ackerschmalwand}, language = {en} } @phdthesis{Pfitzner2019, author = {Pfitzner, Christian}, title = {Visual Human Body Weight Estimation with Focus on Clinical Applications}, isbn = {978-3-945459-27-0 (online)}, doi = {10.25972/OPUS-17484}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-174842}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {It is the aim of this thesis to present a visual body weight estimation, which is suitable for medical applications. A typical scenario where the estimation of the body weight is essential, is the emergency treatment of stroke patients: In case of an ischemic stroke, the patient has to receive a body weight adapted drug, to solve a blood clot in a vessel. The accuracy of the estimated weight influences the outcome of the therapy directly. However, the treatment has to start as early as possible after the arrival at a trauma room, to provide sufficient treatment. Weighing a patient takes time, and the patient has to be moved. Furthermore, patients are often not able to communicate a value for their body weight due to their stroke symptoms. Therefore, it is state of the art that physicians guess the body weight. A patient receiving a too low dose has an increased risk that the blood clot does not dissolve and brain tissue is permanently damaged. Today, about one-third gets an insufficient dosage. In contrast to that, an overdose can cause bleedings and further complications. Physicians are aware of this issue, but a reliable alternative is missing. The thesis presents state-of-the-art principles and devices for the measurement and estimation of body weight in the context of medical applications. While scales are common and available at a hospital, the process of weighing takes too long and can hardly be integrated into the process of stroke treatment. Sensor systems and algorithms are presented in the section for related work and provide an overview of different approaches. The here presented system -- called Libra3D -- consists of a computer installed in a real trauma room, as well as visual sensors integrated into the ceiling. For the estimation of the body weight, the patient is on a stretcher which is placed in the field of view of the sensors. The three sensors -- two RGB-D and a thermal camera -- are calibrated intrinsically and extrinsically. Also, algorithms for sensor fusion are presented to align the data from all sensors which is the base for a reliable segmentation of the patient. A combination of state-of-the-art image and point cloud algorithms is used to localize the patient on the stretcher. The challenges in the scenario with the patient on the bed is the dynamic environment, including other people or medical devices in the field of view. After the successful segmentation, a set of hand-crafted features is extracted from the patient's point cloud. These features rely on geometric and statistical values and provide a robust input to a subsequent machine learning approach. The final estimation is done with a previously trained artificial neural network. The experiment section offers different configurations of the previously extracted feature vector. Additionally, the here presented approach is compared to state-of-the-art methods; the patient's own assessment, the physician's guess, and an anthropometric estimation. Besides the patient's own estimation, Libra3D outperforms all state-of-the-art estimation methods: 95 percent of all patients are estimated with a relative error of less than 10 percent to ground truth body weight. It takes only a minimal amount of time for the measurement, and the approach can easily be integrated into the treatment of stroke patients, while physicians are not hindered. Furthermore, the section for experiments demonstrates two additional applications: The extracted features can also be used to estimate the body weight of people standing, or even walking in front of a 3D camera. Also, it is possible to determine or classify the BMI of a subject on a stretcher. A potential application for this approach is the reduction of the radiation dose of patients being exposed to X-rays during a CT examination. During the time of this thesis, several data sets were recorded. These data sets contain the ground truth body weight, as well as the data from the sensors. They are available for the collaboration in the field of body weight estimation for medical applications.}, subject = {Punktwolke}, language = {en} } @phdthesis{Tscharn2019, author = {Tscharn, Robert}, title = {Innovative And Age-Inclusive Interaction Design with Image-Schematic Metaphors}, doi = {10.25972/OPUS-17576}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175762}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The field of human-computer interaction (HCI) strives for innovative user interfaces. Innovative and novel user interfaces are a challenge for a growing population of older users and endanger older adults to be excluded from an increasingly digital world. This is because older adults often have lower cognitive abilities and little prior experiences with technology. This thesis aims at resolving the tension between innovation and age-inclusiveness by developing user interfaces that can be used regardless of cognitive abilities and technology-dependent prior knowledge. The method of image-schematic metaphors holds promises for innovative and age-inclusive interaction design. Image-schematic metaphors represent a form of technology-independent prior knowledge. They reveal basic mental models and can be gathered in language (e.g. bank account is container from "I put money into my bank account"). Based on a discussion of previous applications of image-schematic metaphors in HCI, the present work derives three empirical research questions regarding image-schematic metaphors for innovative and age-inclusive interaction design. The first research question addresses the yet untested assumption that younger and older adults overlap in their technology-independent prior knowledge and, therefore, their usage of image-schematic metaphors. In study 1, a total of 41 participants described abstract concepts from the domains of online banking and everyday life. In study 2, ten contextual interviews were conducted. In both studies, younger and older adults showed a substantial overlap of 70\% to 75\%, indicating that also their mental models overlap substantially. The second research question addresses the applicability and potential of image-schematic metaphors for innovative design from the perspective of designers. In study 3, 18 student design teams completed an ideation process with either an affinity diagram as the industry standard, image-schematic metaphors or both methods in combination and created paper prototypes. The image-schematic metaphor method alone, but not the combination of both methods, was readily adopted and applied just as a well as the more familiar standard method. In study 4, professional interaction designers created prototypes either with or without image-schematic metaphors. In both studies, the method of image-schematic metaphors was perceived as applicable and creativity stimulating. The third research question addresses whether designs that explicitly follow image-schematic metaphors are more innovative and age-inclusive regarding differences in cognitive abilities and prior technological knowledge. In two experimental studies (study 5 and 6) involving a total of 54 younger and 53 older adults, prototypes that were designed with image-schematic metaphors were perceived as more innovative compared to those who were designed without image-schematic metaphors. Moreover, the impact of prior technological knowledge on interaction was reduced for prototypes that had been designed with image-schematic metaphors. However, participants' cognitive abilities and age still influenced the interaction significantly. The present work provides empirical as well as methodological findings that can help to promote the method of image-schematic metaphors in interaction design. As a result of these studies it can be concluded that the image-schematic metaphors are an applicable and effective method for innovative user interfaces that can be used regardless of prior technological knowledge.}, subject = {Mensch-Maschine-Kommunikation}, language = {en} } @inproceedings{OPUS4-17720, title = {Texts, Animals, Environments: Zoopoetics and Ecopoetics}, editor = {Middelhoff, Frederike and Sch{\"o}nbeck, Sebastian and Borgards, Roland and Gersdorf, Catrin}, edition = {1. Auflage}, publisher = {Rombach Druck- und Verlagshaus}, address = {Freiburg i. Br.}, issn = {978-3-7930-9928-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177209}, pages = {359}, year = {2019}, abstract = {Texts, Animals, Environments. Zoopoetics and Ecopoetics probes the multiple links between ecocriticism and animal studies, assessing the relations between animals, environments and poetics. While ecocriticism usually relies on a relational approach to explore phenomena related to the environment or ecology more broadly, animal studies tends to examine individual or species-specific aspects. As a consequence, ecocriticism concentrates on ecopoetical, animal studies on zoopoetical elements and modes of representation in literature (and the arts more generally). Bringing key concepts of ecocriticism and animal studies into dialogue, the volume explores new ways of thinking about and reading texts, animals, and environments - not as separate entities but as part of the same collective.}, language = {en} } @phdthesis{Rasheed2019, author = {Rasheed, Huma}, title = {Development of simple and cost-effective High Performance Liquid Chromatography methods for quality control of essential beta-lactam antibiotics in low- and middle-income countries}, doi = {10.25972/OPUS-17721}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177214}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Assay and impurity profiling of the pharmaceuticals are the key routine quality control methods employed worldwide for which High Performance Liquid Chromatography (HPLC) is the most widely used technique. The ability to carry out these routine laboratory procedures in low- and middle- income countries (LMICs) need the methods to be based upon simple instruments manageable with moderate levels of personnel skill and costs involved. Simple, convenient, and cost effective reverse phase HPLC methods were developed using phosphate buffer and methanol as mobile phase with C18 column as stationary phase for the impurity profiling and assay of beta lactam antibiotics. Isocratic elution and UV detection was employed in these methods. Impurity profiling method was developed for coamoxiclav tablets and ceftriaxone bulk drug. The method for ceftriaxone included a supplementary method to quantify one of its known impurity (Impurity D of ceftriaxone). This method involved use of acetonitrile where as the two main methods were achieved on the targeted method design, described above. With the exception of impurity A of ceftriaxone, the methods developed can successfully quantify impurities to the concentration as low as ≤0.05\%, which is in accordance with the current guidelines for the impurity profiling of antibiotics issued by European Medicines Agency. As ensuring cost reduction was one of the key objectives of carrying out the method development exercise, in situ methods for the preparation of impurities were also identified and some new methods were introduced. The stability of beta lactam antibiotics and the choice of solvent were given due attention during the process of method development revealing information on the presence of new impurities. Deacetyl cefotaxime and 2-mercaptobenzathiazole were identified in this process as new impurities of ceftriaxone currently not listed under known impurities by United States Pharmacopoeia and European Pharmacopoeia. However, deacetyl cefotaxime is a known impurity of cefotaxime whereas the latter molecule is a degradation product of one of the synthesis impurities of ceftriaxone. This substance is reported to be carcinogenic and is resolved using the supplementary method developed for ceftriaxone, hence making its detection and quantification possible. A known inactive impurity of ceftriaxone (Impurity A, E-isomer of ceftriaxone) was` also shown to be produced by exposure to day light, thus warranting the light protection of the ceftriaxone solution, an information that is of critical importance in the clinical settings. A series of experimentation was carried out on the finished products of beta lactam antibiotics sampled from Pakistan and few other countries, to identify key quality issues in the samples. Though the limited sample size and convenient sampling did not provide results that could yield a decisive figure for the country status for prevalence of substandard and falsified medical products, but the experiments have clearly indicated that the problems in drug quality do exist and beta lactam antibiotics form a class of high-risk medicine with respect to surveillance for poor-quality medicines. Isolation of unknown impurities was also carried out along with the introduction of new and modified methods for preparation of impurities of beta-lactam antibiotics. In addition, detailed literature survey was carried out for understanding the complex problem of the poor-quality medicine, impact of poor quality antimicrobials on health care system and the magnitude of the problem at the global level. The country status of Pakistan regarding quality of medicines was recorded based upon the available documentary evidence. The current technologies and strategic options available for low- and middle-income countries in aiding fight for combating poor quality medicines was also laid down to design recommendations for Pakistan. A comprehensive review of the information technology tools used for identification and control of substandard and falsified medicines was also conducted.}, subject = {HPLC}, language = {en} } @phdthesis{Metter2019, author = {Metter, Christopher Valentin}, title = {Resilience, Availabilty, and Serviceability Evaluation in Software-defined Networks}, issn = {1432-8801}, doi = {10.25972/OPUS-17678}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176788}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {With the introduction of Software-defined Networking (SDN) in the late 2000s, not only a new research field has been created, but a paradigm shift was initiated in the broad field of networking. The programmable network control by SDN is a big step, but also a stumbling block for many of the established network operators and vendors. As with any new technology the question about the maturity and the productionreadiness of it arises. Therefore, this thesis picks specific features of SDN and analyzes its performance, reliability, and availability in scenarios that can be expected in production deployments. The first SDN topic is the performance impact of application traffic in the data plane on the control plane. Second, reliability and availability concerns of SDN deployments are exemplary analyzed by evaluating the detection performance of a common SDN controller. Thirdly, the performance of P4, a technology that enhances SDN, or better its impact of certain control operations on the processing performance is evaluated.}, subject = {Leistungsbewertung}, language = {en} } @phdthesis{Weller2019, author = {Weller, Lisa}, title = {How to not act? Cognitive foundations of intentional nonactions}, doi = {10.25972/OPUS-17667}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176678}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Human actions are generally not determined by external stimuli, but by internal goals and by the urge to evoke desired effects in the environment. To reach these effects, humans typically have to act. But at times, deciding not to act can be better suited or even the only way to reach a desired effect. What mental processes are involved when people decide not to act to reach certain effects? From the outside it may seem that nothing remarkable is happening, because no action can be observed. However, I present three studies which disclose the cognitive processes that control nonactions. The present experiments address situations where people intentionally decide to omit certain actions in order to produce a predictable effect in the environment. These experiments are based on the ideomotor hypothesis, which suggests that bidirectional associations can be formed between actions and the resulting effects. Because of these associations, anticipating the effects can in turn activate the respective action. The results of the present experiments show that associations can be formed between nonactions (i.e., the intentional decision not to act) and the resulting effects. Due to these associations, perceiving the nonaction effects encourages not acting (Exp. 1-3). What is more, planning a nonaction seems to come with an activation of the effects that inevitably follow the nonaction (Exp. 4-5). These results suggest that the ideomotor hypothesis can be expanded to nonactions and that nonactions are cognitively represented in terms of their sensory effects. Furthermore, nonaction effects can elicit a sense of agency (Exp. 6-8). That is, even though people refrain from acting, the resulting nonaction effects are perceived as self-produced effects. In a nutshell, these findings demonstrate that intentional nonactions include specific mechanisms and processes, which are involved, for instance, in effect anticipation and the sense of agency. This means that, while it may seem that nothing remarkable is happening when people decide not to act, complex processes run on the inside, which are also involved in intentional actions.}, subject = {Intention}, language = {en} } @phdthesis{Harbrecht2019, author = {Harbrecht, Isabelle}, title = {Entering Society - The Adolescence, Identity and Development of Vocational Education Students in Shanghai}, edition = {1. Auflage}, publisher = {W{\"u}rzburg University Press}, address = {W{\"u}rzburg}, isbn = {978-3-95826-096-2}, doi = {10.25972/WUP-978-3-95826-097-9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-168626}, school = {W{\"u}rzburg University Press}, pages = {xviii, 298}, year = {2019}, abstract = {With the late twentieth-century reform of the labour market and the abolition of the 'iron rice bowl' in China, jobs were no longer guaranteed by the government and higher education became more and more a requirement for even low-level positions. A surplus of academics and a lack of skilled workers became the long-term consequences. Since the early 2000s, the government has tried to mitigate this situation by promoting and developing vocational education. However, it is still considered to be a second class education, suitable only for weak students whose results are too low for an academic middle school. Based on the qualitative and quantitative data of a three-year panel study conducted in vocational schools in Shanghai, the present publication analyses the social environments, personalities, values and perceptions of students in vocational education - adolescents stigmatized by society. The results show how their attitudes change throughout their education, and which kinds of identities they form. Drawing on Ulrich Beck's thesis of individualization, this publication finds that adolescents in vocational education still hold on to the belief that good study results enable them to seize chances and avoid risks. Freedom of choice, feelings of success and a good relationship with parents support these positive attitudes towards learning. Family in particular turned out to not only be an important motivational factor but also the dominant value of the students. Vocational education is still, however, stigmatized and the adolescents try to bring that in line with their self-worth.}, language = {en} } @phdthesis{Wahl2019, author = {Wahl, Joachim}, title = {The Use of Ionic Liquids in Capillary Electrophoresis Enantioseparation}, doi = {10.25972/OPUS-17639}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176397}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Two chiral chemical molecules being mirror images of each other, also referred to as enantiomers, may have different pharmacokinetic, pharmacodynamic, and toxicological effects. Thus, pharmaceutical manufacturers and authorities are increasingly interested in the approval of enantiopure drugs. However, the isomeric purity and the limits for isomeric impurities have to be specified applying enantioselective analytical methods, such as capillary electrophoresis. The separation of enantiomers in capillary electrophoresis may be improved by the addition of ionic liquids to the background electrolyte. The aim of this work was to investigate the influence of different separation conditions on the enantioseparation of phenethylamines in background electrolytes containing ionic liquids based on tetrabutylammonium cations. Best chiral separations were achieved at acidic pH values using phosphate buffers containing 125 mmol/L tetrabutylammonium based salts. Different reasons explaining enhanced enantioseparations in buffers containing ionic liquids were found. First, due to an improvement of the cyclodextrin solubility, the addition of ionic liquids to the background electrolyte enables the use of higher concentrations of these chiral selector. Furthermore, the adsorption of tetrabutylammonium cations to the negatively charged capillary surface results in a reduction of the electroosmotic flow. Hence, the resulting prolongation of migration times leads to a longer period of time for the separation of temporarily formed diastereomeric analyte cyclodextrin complexes, which yields improved enantioseparation. Additionally, due to a decrease of the adsorption of positively charged phenethylamine analyte molecules to capillary surface silanol groups, the adsorption of ionic liquid cations inhibits peak broadening. A further reason explaining an enhanced enantioseparation by the addition of ionic liquids to the background electrolyte is a competition between tetrabutylammonium cations and analyte enantiomers for the inclusion into cyclodextrin cavities. Furthermore, the influence of different chiral counterions, combined with tetrabutylammonium cations, on the enantioseparation of phenethylamines was investigated. Solely anions based on the basic proteinogenic amino acids L lysine and L arginine yielded chiral separation results superior to those achieved using achiral tetrabutylammonium chloride as background electrolyte additive. Especially the application of tetrabutylammonium L argininate gave very good enantioseparations of all investigated ephedrine derivatives, which might be explained by the ability of L arginine to affect the formation of complexes between analytes and cyclodextrins. Besides the investigation of the influence of ionic liquids on the enantioseparation, complexes between phenethylamine enantiomers and β cyclodextrin derivatives were characterized by affinity capillary electrophoresis. The binding constants between analyte enantiomers and cyclodextrins and the electrophoretic mobilities of the temporarily formed complexes were determined and compared to the observed chiral resolution values. While neither the calculated binding constants nor their differences correlated with the quality of the enantioseparation, a strong correlation between the differences of the electrophoretic mobilities of the complexes and the chiral resolution values was found.}, subject = {Kapillarelektrophorese}, language = {en} } @phdthesis{Mekala2019, author = {Mekala, SubbaRao}, title = {Generation of cardiomyocytes from vessel wall-resident stem cells}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-146046}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Myocardial infarction (MI) is a major cause of health problems and is among the leading deadly ending diseases. Accordingly, regenerating functional myocardial tissue and/or cardiac repair by stem cells is one of the most desired aims worldwide. Indeed, the human heart serves as an ideal target for regenerative intervention, because the capacity of the adult myocardium to restore itself after injury or infarct is limited. Thus, identifying new sources of tissue resident adult stem or progenitor cells with cardiovascular potential would help to establish more sophisticated therapies in order to either prevent cardiac failure or to achieve a functional repair. Ongoing research worldwide in this field is focusing on a) induced pluripotent stem (iPS) cells, b) embryonic stem (ES) cells and c) adult stem cells (e. g. mesenchymal stem cells) as well as cardiac fibroblasts or myofibroblasts. However, thus far, these efforts did not result in therapeutic strategies that were transferable into the clinical management of MI and heart failure. Hence, identifying endogenous and more cardiac-related sources of stem cells capable of differentiating into mature cardiomyocytes would open promising new therapeutic opportunities. The working hypothesis of this thesis is that the vascular wall serves as a niche for cardiogenic stem cells. In recent years, various groups have identified different types of progenitors or mesenchymal stem cell-like cells in the adventitia and sub-endothelial zone of the adult vessel wall, the so called vessel wall-resident stem cells (VW-SCs). Considering the fact that heart muscle tissue contains blood vessels in very high density, the physiological relevance of VW-SCs for the myocardium can as yet only be assumed. The aim of the present work is to study whether a subset of VW-SCs might have the capacity to differentiate into cardiomyocyte-like cells. This assumption was challenged using adult mouse aorta-derived cells cultivated in different media and treated with selected factors. The presented results reveal the generation of spontaneously beating cardiomyocyte-like cells using specific media conditions without any genetic manipulation. The cells reproducibly started beating at culture days 8-10. Further analyses revealed that in contrast to several publications reporting the Sca-1+ cells as cardiac progenitors the Sca-1- fraction of aortic wall-derived VW-SCs reproducibly delivered beating cells in culture. Similar to mature cardiomyocytes the beating cells developed sarcomeric structures indicated by the typical cross striated staining pattern upon immunofluorescence analysis detecting α-sarcomeric actinin (α-SRA) and electron microscopic analysis. These analyses also showed the formation of sarcoplasmic reticulum which serves as calcium store. Correspondingly, the aortic wall-derived beating cardiomyocyte-like cells (Ao-bCMs) exhibited calcium oscillations. This differentiation seems to be dependent on an inflammatory microenvironment since depletion of VW-SC-derived macrophages by treatment with clodronate liposomes in vitro stopped the generation of Ao bCMs. These locally generated F4/80+ macrophages exhibit high levels of VEGF (vascular endothelial growth factor). To a great majority, VW-SCs were found to be positive for VEGFR-2 and blocking this receptor also stopped the generation VW-SC-derived beating cells in vitro. Furthermore, the treatment of aortic wall-derived cells with the ß-receptor agonist isoproterenol or the antagonist propranolol resulted in a significant increase or decrease of beating frequency. Finally, fluorescently labeled aortic wall-derived cells were implanted into the developing chick embryo heart field where they became positive for α-SRA two days after implantation. The current data strongly suggest that VW-SCs resident in the vascular adventitia deliver both progenitors for an inflammatory microenvironment and beating cells. The present study identifies that the Sca-1- rather than Sca-1+ fraction of mouse aortic wall-derived cells harbors VW-SCs differentiating into cardiomyocyte-like cells and reveals an essential role of VW-SCs-derived inflammatory macrophages and VEGF-signaling in this process. Furthermore, this study demonstrates the cardiogenic capacity of aortic VW-SCs in vivo using a chimeric chick embryonic model.}, subject = {Herzmuskelzelle}, language = {en} } @phdthesis{Yu2019, author = {Yu, Sung-Huan}, title = {Development and application of computational tools for RNA-Seq based transcriptome annotations}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176468}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {In order to understand the regulation of gene expression in organisms, precise genome annotation is essential. In recent years, RNA-Seq has become a potent method for generating and improving genome annotations. However, this Approach is time consuming and often inconsistently performed when done manually. In particular, the discovery of non-coding RNAs benefits strongly from the application of RNA-Seq data but requires significant amounts of expert knowledge and is labor-intensive. As a part of my doctoral study, I developed a modular tool called ANNOgesic that can detect numerous transcribed genomic features, including non-coding RNAs, based on RNA-Seq data in a precise and automatic fashion with a focus on bacterial and achaeal species. The software performs numerous analyses and generates several visualizations. It can generate annotations of high-Resolution that are hard to produce using traditional annotation tools that are based only on genome sequences. ANNOgesic can detect numerous novel genomic Features like UTR-derived small non-coding RNAs for which no other tool has been developed before. ANNOgesic is available under an open source license (ISCL) at https://github.com/Sung-Huan/ANNOgesic. My doctoral work not only includes the development of ANNOgesic but also its application to annotate the transcriptome of Staphylococcus aureus HG003 - a strain which has been a insightful model in infection biology. Despite its potential as a model, a complete genome sequence and annotations have been lacking for HG003. In order to fill this gap, the annotations of this strain, including sRNAs and their functions, were generated using ANNOgesic by analyzing differential RNA-Seq data from 14 different samples (two media conditions with seven time points), as well as RNA-Seq data generated after transcript fragmentation. ANNOgesic was also applied to annotate several bacterial and archaeal genomes, and as part of this its high performance was demonstrated. In summary, ANNOgesic is a powerful computational tool for RNA-Seq based annotations and has been successfully applied to several species.}, subject = {Genom}, language = {en} } @phdthesis{Berninger2019, author = {Berninger, Michael}, title = {Development of Novel Quinolone Amides Against the African Sleeping Sickness - A Fluorine Walk}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176428}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {In recent years the transmission of the Human African Trypanosomiasis could be significantly reduced. The reported cases in 2016 reached a historic low level of 2184 cases and these achievements can be ascribed to intense control and surveillance programmes.118 However, most of the reported cases (>1000 in 2015) occurred in the Democratic Republic of the Congo and thus, need to be treated adequately. In particular, when the parasites have traversed the blood-brain barrier (BBB), treatment proved to be even more difficult. In addition, the number of cases always came in waves due to many reasons, e.g., development of resistances. Thus, it can be expected from experiences of the past that the number of cases will increase again. Hence, novel chemical entities are desperately needed in order to overcome the drawbacks which are associated with the current treatment options. Our drug discovery approach included an initial drug repurposing strategy combined with a phenotypic screening. S. Niedermeier found novel active compounds derived from commercial fluoroquinolones. The most promising hit compound was further developed by G. Hiltensperger resulting in the lead quinolone amide GHQ168 (IC50 = 0.047 µM). This doctoral thesis is about new insights into the SAR of the quinolone amides and the enhancement of the lead compound. Special consideration was given to the fluorine atom in the quinolone amides and how certain fluorine substitution patterns influence the antitrypanosomal activity, physicochemical properties and pharmacokinetics (i.e. 'fluorine walk'). Moreover, the ability of the compound class crossing the BBB should be investigated. This feature is inevitable necessary in order to potentially treat African sleeping sickness stage II. The Gould-Jacobs protocol was predominantly used for the synthesis of the quinolone core. Since former SAR studies mainly concentrated on the variation in positions 1, 3 and 7, quinolone scaffolds (2a-i) with diverse substitution patterns regarding positions 5, 6, 7 and 8 were synthesised in this thesis. The resulting quinolone amides were evaluated for their antitrypanosomal activity. Voluminous residues in position C-5 resulted in diminished activities (compounds 13, 16 and 18) and solely small-sized moieties were tolerated. In particular the fluorine atom in position 5 revealed beneficial trypanocidal effects as shown for compounds 6 (IC50 = 0.05 µM), 8 (IC50 = 0.04 µM), and 24 (IC50 = 0.02 µM). Furthermore, having fluorine only in position 5 of the quinolone core could considerably reduce the cytotoxic effects (CC50 >100 µM, SI = >2000 for 6). Hence, the 5-fluoro-substituted quinolone amides were considered superior to GHQ168. Regarding the C-6 position all other moieties (e.g., H in 9, OCH3 in 10, CF3 in 12) except of a fluorine atom decreased the activity against Trypanosoma brucei brucei. A double fluorination in C-6 and C-8 was not beneficial (IC50 = 0.06 µM for 7) and a single fluorine atom in C-8 even showed a negative effect (IC50 = 0.79 µM for 5). The logP value is considered a surrogate parameter for lipophlicity and thus, affecting permeability and solubility processes. In particular the fluorine atom influences the lipophilicity due to versatile effects: Lipophilicity is increased by additional fluorine atoms on aromatic rings (7, 23) and reduced by fluorine atoms at an alkyl chain (49), respectively. Additionally, the 5-fluoro-substituted quinolone amides (6, 8, and 24) could prove the contrary effect of decreasing lipophilicity when the aromatic fluorine substituent is in vicinity to a carbonyl group. For the most promising drug candidates 6, 23, and 24 the respective metabolites and the metabolic turnover were investigated by C. Erk. In comparison to GHQ168 the hydroxylation of the benzylamide was prevented by the para-fluorine atom. Hence, half-life was extended for compound 23 (t1/2 = 6.4 h) and N-desalkylation was the predominant pathway. Moreover, the respective fluorine substitution pattern of the quinolone core affected the metabolism of compound 6. The 5-fluoro-substituted quinolone amide was less prone for biotransformation (t1/2 = 7.2 h) and half-life could even be further prolonged for compound 24 (t1/2 = 7.7 h). Due to the most appropriate safety profile of compound 6, this particular drug candidate was considered for in vivo study. Its poor solubility made a direct intraperitoneal administration unfeasible. Thus, an amorphous solid dispersion of 6 was generated using the spray-drying method according to the previous protocol. Unfortunately, the required solubility for the predicted in vivo study was not achieved. Furthermore, the compound class of the quinolone amide was evaluated for its ability for brain penetration. The methanesulfonyl precursor 48 was synthesised and subsequently radiofluorinated in the group of Prof. Dr. Samnick (Department of Nuclear Medicine, University Hospital of W{\"u}rzburg). The labelled compound [18F]49 was administered to mice, and its distribution throughout the body was analysed using positron emission tomography and autoradiography, respectively. The autoradiography of the murine brains revealed medium to high concentrations of [18F]49. Therefore, the quinolone amides are generally suitable for treating Human African Trypanosomiasis stage II. A scaffold hopping approach was performed starting from the quinolone amides and concluding with the compound class of pyrazoloquinolin-3-ones. The intramolecular hydrogen bond between the sec. amide and the C-4 carbonyl moiety was replaced by a covalent bond. The two compound classes were comparable regarding the antitrypanosomal activity to some degree (IC50 = 7.9 µM (EK02) vs. 6.37 µM (53a)). However, a final evaluation of 59 was not possible due to poor solubility.}, subject = {Trypanosomiase}, language = {en} } @phdthesis{Hieke2019, author = {Hieke, Marie}, title = {Synaptic arrangements and potential communication partners of \(Drosophila's\) PDF-containing clock neurons within the accessory medulla}, doi = {10.25972/OPUS-17598}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175988}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Endogenous clocks regulate physiological as well as behavioral rhythms within all organisms. They are well investigated in D. melanogaster on a molecular as well as anatomical level. The neuronal clock network within the brain represents the center for rhythmic activity control. One neuronal clock subgroup, the pigment dispersing factor (PDF) neurons, stands out for its importance in regulating rhythmic behavior. These neurons express the neuropeptide PDF (pigment dispersing factor). A small neuropil at the medulla's edge, the accessory medulla (AME), is of special interest, as it has been determined as the main center for clock control. It is not only highly innervated by the PDF neurons but also by terminals of all other clock neuron subgroups. Furthermore, terminals of the photoreceptors provide light information to the AME. Many different types of neurons converge within the AME and afterward spread to their next target. Thereby the AME is supplied with information from a variety of brain regions. Among these neurons are the aminergic ones whose receptors' are expressed in the PDF neurons. The present study sheds light onto putative synaptic partners and anatomical arrangements within the neuronal clock network, especially within the AME, as such knowledge is a prerequisite to understand circadian behavior. The aminergic neurons' conspicuous vicinity to the PDF neurons suggests synaptic communication among them. Thus, based on former anatomical studies regarding this issue detailed light microscopic studies have been performed. Double immunolabellings, analyses of the spatial relation of pre- and postsynaptic sites of the individual neuron populations with respect to each other and the identification of putative synaptic partners using GRASP reenforce the hypothesis of synaptic interactions within the AME between dopaminergic/ serotonergic neurons and the PDF neurons. To shed light on the synaptic partners I performed first steps in array tomography, as it allows terrific informative analyses of fluorescent signals on an ultrastructural level. Therefore, I tested different ways of sample preparation in order to achieve and optimize fluorescent signals on 100 nm thin tissue sections and I made overlays with electron microscopic images. Furthermore, I made assumptions about synaptic modulations within the neuronal clock network via glial cells. I detected their cell bodies in close vicinity to the AME and PDFcontaining clock neurons. It has already been shown that glial cells modulate the release of PDF from s-LNvs' terminals within the dorsal brain. On an anatomical level this modulation appears to exist also within the AME, as synaptic contacts that involve PDF-positive dendritic terminals are embedded into glial fibers. Intriguingly, these postsynaptic PDF fibers are often VIIAbstract part of dyadic or even multiple-contact sites in opposite to prolonged presynaptic active zonesimplicating complex neuronal interactions within the AME. To unravel possible mechanisms of such synaptic arrangements, I tried to localize the ABC transporter White. Its presence within glial cells would indicate a recycling mechanism of transmitted amines which allows their fast re-provision. Taken together, synapses accompanied by glial cells appear to be a common arrangement within the AME to regulate circadian behavior. The complexity of mechanisms that contribute in modulation of circadian information is reflected by the complex diversity of synaptic arrangements that involves obviously several types of neuron populations}, subject = {Taufliege}, language = {en} } @phdthesis{Weber2019, author = {Weber, Manuel}, title = {Action-based quantum Monte Carlo approach to fermion-boson models}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157643}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {This work deals with the development and application of novel quantum Monte Carlo methods to simulate fermion-boson models. Our developments are based on the path-integral formalism, where the bosonic degrees of freedom are integrated out exactly to obtain a retarded fermionic interaction. We give an overview of three methods that can be used to simulate retarded interactions. In particular, we develop a novel quantum Monte Carlo method with global directed-loop updates that solves the autocorrelation problem of previous approaches and scales linearly with system size. We demonstrate its efficiency for the Peierls transition in the Holstein model and discuss extensions to other fermion-boson models as well as spin-boson models. Furthermore, we show how with the help of generating functionals bosonic observables can be recovered directly from the Monte Carlo configurations. This includes estimators for the boson propagator, the fidelity susceptibility, and the specific heat of the Holstein model. The algorithmic developments of this work allow us to study the specific heat of the spinless Holstein model covering its entire parameter range. Its key features are explained from the single-particle spectral functions of electrons and phonons. In the adiabatic limit, the spectral properties are calculated exactly as a function of temperature using a classical Monte Carlo method and compared to results for the Su-Schrieffer-Heeger model.}, subject = {Monte-Carlo-Simulation}, language = {en} } @phdthesis{Albert2019, author = {Albert, Michael}, title = {Intelligent analysis of medical data in a generic telemedicine infrastructure}, isbn = {978-3-945459-26-3 (Online)}, doi = {10.25972/OPUS-17421}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-174213}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Telemedicine uses telecommunication and information technology to provide health care services over spatial distances. In the upcoming demographic changes towards an older average population age, especially rural areas suffer from a decreasing doctor to patient ratio as well as a limited amount of available medical specialists in acceptable distance. These areas could benefit the most from telemedicine applications as they are known to improve access to medical services, medical expertise and can also help to mitigate critical or emergency situations. Although the possibilities of telemedicine applications exist in the entire range of healthcare, current systems focus on one specific disease while using dedicated hardware to connect the patient with the supervising telemedicine center. This thesis describes the development of a telemedical system which follows a new generic design approach. This bridges the gap of existing approaches that only tackle one specific application. The proposed system on the contrary aims at supporting as many diseases and use cases as possible by taking all the stakeholders into account at the same time. To address the usability and acceptance of the system it is designed to use standardized hardware like commercial medical sensors and smartphones for collecting medical data of the patients and transmitting them to the telemedical center. The smartphone can also act as interface to the patient for health questionnaires or feedback. The system can handle the collection and transport of medical data, analysis and visualization of the data as well as providing a real time communication with video and audio between the users. On top of the generic telemedical framework the issue of scalability is addressed by integrating a rule-based analysis tool for the medical data. Rules can be easily created by medical personnel via a visual editor and can be personalized for each patient. The rule-based analysis tool is extended by multiple options for visualization of the data, mechanisms to handle complex rules and options for performing actions like raising alarms or sending automated messages. It is sometimes hard for the medical experts to formulate their knowledge into rules and there may be information in the medical data that is not yet known. This is why a machine learning module was integrated into the system. It uses the incoming medical data of the patients to learn new rules that are then presented to the medical personnel for inspection. This is in line with European legislation where the human still needs to be in charge of such decisions. Overall, we were able to show the benefit of the generic approach by evaluating it in three completely different medical use cases derived from specific application needs: monitoring of COPD (chronic obstructive pulmonary disease) patients, support of patients performing dialysis at home and councils of intensive-care experts. In addition the system was used for a non-medical use case: monitoring and optimization of industrial machines and robots. In all of the mentioned cases, we were able to prove the robustness of the generic approach with real users of the corresponding domain. This is why we can propose this approach for future development of telemedical systems.}, subject = {Telemedizin}, language = {en} } @phdthesis{Reyes2019, author = {Reyes, Ignacio A.}, title = {Aspects of quantum gravity in AdS\(_3\)/CFT\(_2\)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175613}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The quest for finding a unifying theory for both quantum theory and gravity lies at the heart of much of the research in high energy physics. Although recent years have witnessed spectacular experimental confirmation of our expectations from Quantum Field Theory and General Relativity, the question of unification remains as a major open problem. In this context, the perturbative aspects of quantum black holes represent arguably the best of our knowledge of how to proceed in this pursue. In this thesis we investigate certain aspects of quantum gravity in 2 + 1 dimensional anti-de Sitter space (AdS3), and its connection to Conformal field theories in 1 + 1 dimensions (CFT2), via the AdS/CFT correspondence. We study the thermodynamics properties of higher spin black holes. By focusing on the spin-4 case, we show that black holes carrying higher spin charges display a rich phase diagram in the grand canonical ensemble, including phase transitions of the Hawking-Page type, first order inter-black hole transitions, and a second order critical point. We investigate recent proposals on the connection between bulk codimension-1 volumes and computational complexity in the CFT. Using Tensor Networks we provide concrete evidence of why these bulk volumes are related to the number of gates in a quantum circuit, and exhibit their topological properties. We provide a novel formula to compute this complexity directly in terms of entanglement entropies, using techniques from Kinematic space. We then move in a slightly different direction, and study the quantum properties of black holes via de Functional Renormalisation Group prescription coming from Asymptotic safety. We avoid the arbitrary scale setting by restricting to a narrower window in parameter space, where only Newton's coupling and the cosmological constant are allowed to vary. By one assumption on the properties of Newton's coupling, we find black hole solutions explicitly. We explore their thermodynamical properties, and discover that very large black holes exhibit very unusual features.}, language = {en} } @phdthesis{Mayer2019, author = {Mayer, Rafaela}, title = {OxPAPC as an endogenous agonist of TRPA1 channels on nociceptors}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175890}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Non-steroidal antiinflammatory drugs are most commonly used for inflammatory and postoperative pain. But they lack effectiveness and specificity, leading to severe side effects, like gastric ulcers, asthma and severe bleeding. Oxidized 1-palmitoyl-2-arachinidonoyl-sn-glycero-3-phosphocholine (OxPAPC) plays an important role in inflammatory pain. PAPC is a common phosphatidylcholine of membranes, which can be oxidized by reactive oxygen species. In preliminary experiments, our group found that local injection of OxPAPC in rat paws induces hyperalgesia. In this study we examined the effect of OxPAPC on transient receptor potential A1 (TRPA1), an ion channel expressed in C-fiber neurons. Furthermore, we investigated if intracellular cysteine residues of TRPA1 were necessary for agonist-channel-interactions and if a subsequent TRPA1 activation could be prevented by OxPAPC scavengers. To answer these questions, we performed calcium imaging using HEK-293 cells stably expressing hTRPA1, or transiently expressing the triple mutant channel hTRPA1-3C and na{\"i}ve DRG neurons. Cells were incubated with the ratiometric, fluorescent dye Fura-2/AM and stimulated with OxPAPC. The change of light emission after excitation with 340 and 380 nm wavelengths allowed conclusions regarding changes of intracellular calcium concentrations after TRPA1 activation. In our investigation we proved evidence that OxPAPC activates TRPA1, which caused a flow of calcium ions into the cytoplasm. The TRPA1-specific channel blocker HC-030031 eliminated this agonist-induced response. TRPA1-3C was not completely sensitive to OxPAPC. The peptide D-4F and the monoclonal antibody E06 neutralized OxPAPC-induced TRPA1 activation. In this work, the importance of OxPAPC as a key mediator of inflammatory pain and as a promising target for drug design is highlighted. Our results indicate that TRPA1 activation by OxPAPC involves cysteine-dependent mechanisms, but there are other, cysteine-independent activation mechanisms as well. Potential pharmaceuticals for the treatment of inflammatory pain are D-4F and E06, whose efficiency has recently been confirmed in the animal model by our research group.}, subject = {Schmerzforschung}, language = {en} } @phdthesis{Horn2019, author = {Horn, Jessica}, title = {Molecular and functional characterization of the long non-coding RNA SSR42 in \(Staphylococcus\) \(aureus\)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175778}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Staphylococcus aureus asymptomatically colonizes the skin and anterior nares of 20-30\% of the healthy human population. As an opportunistic human pathogen it elicits a variety of infections ranging from skin and soft tissue infections to highly severe manifestations such as pneumonia, endocarditis and osteomyelitis. Due to the emergence of multi resistant strains, treatment of staphylococcal infections becomes more and more challenging and the WHO therefore classified S. aureus as a "superbug". The variety of diseases triggered by S. aureus is the result of a versatile expression of a large set of virulence factors. The most prominent virulence factor is the cytotoxic and haemolytic pore-forming α-toxin whose expression is mediated by a complex regulatory network involving two-component systems such as the agr quorum-sensing system, accessory transcriptional regulators and alternative sigma-factors. However, the intricate regulatory network is not yet understood in its entirety. Recently, a transposon mutation screen identified the AraC-family transcriptional regulator 'Repressor of surface proteins' (Rsp) to regulate haemolysis, cytotoxicity and the expression of various virulence associated factors. Deletion of rsp was accompanied by a complete loss of transcription of a 1232 nt long non-coding RNA, SSR42. This doctoral thesis focuses on the molecular and functional characterization of SSR42. By analysing the transcriptome and proteome of mutants in either SSR42 or both SSR42 and rsp, as well as by complementation of SSR42 in trans, the ncRNA was identified as the main effector of Rsp-mediated virulence. Mutants in SSR42 exhibited strong effects on transcriptional and translational level when compared to wild-type bacteria. These changes resulted in phenotypic alterations such as strongly reduced haemolytic activity and cytotoxicity towards epithelial cells as well as reduced virulence in a murine infection model. Deletion of SSR42 further promoted the formation of small colony variants (SCV) during long term infection of endothelial cells and demonstrated the importance of this molecule for intracellular bacteria. The impact of this ncRNA on staphylococcal haemolysis was revealed to be executed by modulation of sae mRNA stability and by applying mutational studies functional domains within SSR42 were identified. Moreover, various stressors modulated the transcription of SSR42 and antibiotic challenge resulted in SSR42-dependently increased haemolysis and cytotoxicity. Transcription of SSR42 itself was found under control of various important global regulators including AgrA, SaeS, CodY and σB, thereby illustrating a central position in S. aureus virulence gene regulation. The present study thus demonstrates SSR42 as a global virulence regulatory RNA which is important for haemolysis, disease progression and adaption of S. aureus to intracellular conditions via formation of SCVs.}, subject = {Staphylococcus aureus}, language = {en} } @phdthesis{Wagner2019, author = {Wagner, Martin}, title = {Chronic Kidney Disease as an Important Co-morbid Condition in Coronary Heart Disease Patients}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175498}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {In patients with coronary heart disease (CHD) the control of the modifiable "traditional" cardiovascular risk factors such as hypertension, dyslipidemia, diabetes, achieving/maintaining normal body weight and smoking cessation is of major importance to improve prognosis. Guideline recommendations for secondary CHD prevention include specific treatment targets for blood pressure, lipid levels, and markers of glucose metabolism for both younger and older patients. Chronic kidney disease (CKD) has been identified as a "non-traditional" risk factor for worse outcome in CHD patients, as it is associated with a markedly increased risk for subsequent CV events and mortality. The specific objectives of the current thesis-project are to investigate (a) the quality of care in a recent sample of German CHD patients and to investigate variation of risk factor control between younger and elder patients (≤70 versus >70 years), (b) to analyze the prevalence of CKD across Europe in stable CHD patients in the outpatient setting and during a hospital stay for CHD, (c) to investigate the level of awareness of CKD in German CHD patients and their treating physicians. Data from the European-wide EUROASPIRE IV study were used that include data on 7998 CHD patients in the ambulatory setting (study visit) and during a hospital stay for CHD (index). The German EUROASPIRE IV study center in W{\"u}rzburg recruited 536 patients in 2012-2013. Risk factor control was compared against the current recommendations of the European Society of Cardiology. CKD was described by stages of glomerular filtration rate (eGFR) and albuminuria. German patients were asked in an additional kidney specific module whether they have ever been told by a physician about renal impairment. The fact that CKD or acute kidney injury (AKI) was mentioned in prominent parts of the hospital discharge letter as well as correct ICD-coding of CKD or AKI served as a proxy for physician's awareness of CKD. The majority of German CHD patients was treated with the recommended drug therapies including e.g. β-blockers, anti-platelets and statins. However, treatment targets for blood pressure and LDL-cholesterol levels were not achieved in many patients (45\% and 53\%, respectively) and glycemic control in diabetic CHD patients with HbA1-levels <7\% was insufficient (61\%). A minority of patients reported on current smoking (10\%), but unhealthy life-styles e.g. overweight/obesity (85\%/37\%) were frequent. Patterns of care differed between younger and older CHD patients while older patients were less likely to receive the recommended medical CHD-therapy, were more likely to have uncontrolled blood pressure and also to be diabetic. However, a greater proportion of diabetic patients >70 years was achieving the HbA1c target, and less elder patients were current smokers or were obese. About 17\% of patients on average had CKD (eGFR< 60 ml/min/1.73m²) in the entire European sample at the study visit, and an additional 10\% had albuminuria despite preserved eGFR, with considerable variation among countries. Impaired kidney function was observed in every fifth patient admitted for CHD in the entire European dataset of the EUROASPIRE IV study. Of the German CHD patients with CKD at the study visit, only a third were aware of their renal impairment. A minority of these patients was being seen by nephrologists, however, with a higher likelihood of CKD awareness and specialist care in more advanced stages of CKD. About a third of patients admitted for CHD showed either CKD or AKI during the hospital stay, but the discharge letter mentioned chronic or acute kidney disease only in every fifth of these patients. In contrast, correct ICD coding of CKD or AKI was more complete, but still suboptimal. In summary, quality of secondary prevention in German CHD patients indicates considerably room for improvement, with life-style modifications may become an even greater factor in prevention campaigns than medical treatment into certain target ranges. Preventive therapies should also consider different needs in older individuals acknowledging physical and mental potential, other comorbidities and drug-interactions with co-medication. CKD is common in CHD patients, not only in the elderly. Since CHD and CKD affect each other and impact on worse prognosis of each other, raising the awareness of CKD among patients and physicians and considering CKD in medical therapy may improve prognosis and slow disease progression of CHD as well as CKD.}, language = {en} } @phdthesis{Hell2019, author = {Hell, Dennis}, title = {Development of self-adjusting cytokine neutralizer cells as a closed-loop delivery system of anti-inflammatory biologicals}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175381}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The current treatment strategies for diseases are assessed on the basis of diagnosed phenotypic changes due to an accumulation of asymptomatic events in physiological processes. Since a diagnosis can only be established at advanced stages of the disease, mainly due to insufficient early detection possibilities of physiological disorders, doctors are forced to treat diseases rather than prevent them. Therefore, it is desirable to link future therapeutic interventions to the early detection of physiological changes. So-called sensor-effector systems are designed to recognise disease-specific biomarkers and coordinate the production and delivery of therapeutic factors in an autonomous and automated manner. Such approaches and their development are being researched and promoted by the discipline of synthetic biology, among others. Against this background, this paper focuses on the in vitro design of cytokine-neutralizing sensor-effector cells designed for the potential treatment of recurrent autoimmune diseases, especially rheumatoid arthritis. The precise control of inducible gene expression was successfully generated in human cells. At first, a NF-κB-dependent promoter was developed, based on HIV-1 derived DNA-binding motives. The activation of this triggerable promoter was investigated using several inducers including the physiologically important NF-κB inducers tumor necrosis factor alpha (TNFα) and interleukin 1 beta (IL-1β). The activation strength of the NF-κB-triggered promoter was doubled by integrating a non-coding RNA. The latter combined expressed RNA structures, which mimic DNA by double stranded RNAs and have been demonstrated to bind to p50 or p65 by previous publications. The sensitivity was investigated for TNFα and IL-1β. The detection limit and the EC50 values were in in the lower picomolar range. Besides the sensitivity, the reversibility and dynamic of the inducible system were characterized. Hereby a close correlation between pulse times and expression profile was shown. The optimized NF-κB-dependent promoter was then coupled to established TNFα- and IL-1-blocking biologicals to develop sensor-effector systems with anti-inflammatory activity, and thus potential use against autoimmune diseases such as rheumatoid arthritis. The biologicals were differentiated between ligand-blocking and receptor-blocking biologicals and different variants were selected: Adalimumab, etanercept and anakinra. The non-coding RNA improved again the activation strength of NF-κB-dependent expressed biologicals, indicating its universal benefit. Furthermore, it was shown that the TNFα-induced expression of NF-κB-regulated TNFα-blocking biologics led to an extracellular negative feedback loop. Interestingly, the integration of the non-coding RNA and this negative feedback loop has increased the dynamics and reversibility of the NF-κB-regulated gene expression. The controllability of drug release can also be extended by the use of inhibitors of classical NF-κB signalling such as TPCA-1. The efficacy of the expressed biologicals was detected through neutralization of the cytokines using different experiments. For future in vivo trials, first alginate encapsulations of the cells were performed. Furthermore, the activation of NF-κB-dependent promoter was demonstrated using co-cultures with human plasma samples or using synovial liquids. With this generated sensor-effector system we have developed self-adjusting cytokine neutralizer cells as a closed-loop delivery system for anit-inflammatory biologics.}, subject = {Biologika}, language = {en} } @phdthesis{Wu2019, author = {Wu, Fang}, title = {Adding new functions to insulin-like growth factor-I (IGF-I) via genetic codon expansion}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175330}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Insulin-like growth factor-I (IGF-I) is a 70-amino acid polypeptide with a molecular weight of approximately 7.6 kDa acting as an anabolic effector. It is essential for tissue growth and remodeling. Clinically, it is used for the treatment of growth disorders and has been proposed for various other applications including musculoskeletal diseases. Unlike insulin, IGF-I is complexed to at least six high-affinity binding proteins (IGFBPs) exerting homeostatic effects by modulating IGF-I availability to its receptor (IGF-IR) on most cells in the body as well as changing the distribution of the growth factor within the organism.1-3 Short half-lived IGF-I have been the driving forces for the design of localized IGF-I depot systems or protein modification with enhanced pharmacokinetic properties. In this thesis, we endeavor to present a versatile biologic into which galenical properties were engineered through chemical synthesis, e.g., by site-specific coupling of biomaterials or complex composites to IGF-I. For that, we redesigned the therapeutic via genetic codon expansion resulting in an alkyne introduced IGF-I, thereby becoming a substrate for biorthogonal click chemistries yielding a site-specific decoration. In this approach, an orthogonal pyrrolysine tRNA synthetase (PylRS)/tRNAPyl CUA pair was employed to direct the co-translational incorporation of an unnatural amino acid—¬propargyl-L-lysine (plk)—bearing a clickable alkyne functional handle into IGF-I in response to the amber stop codon (UAG) introduced into the defined position in the gene of interest. We summarized the systematic optimization of upstream and downstream process alike with the ultimate goal to increase the yield of plk modified IGF-I therapeutic, from the construction of gene fusions resulting in (i) Trx-plk-IGF-I fusion variants, (ii) naturally occurring pro-IGF-I protein (IGF-I + Ea peptide) (plk-IGF-I Ea), over the subsequent bacterial cultivation and protein extraction to the final chromatographic purification. The opportunities and hurdles of all of the above strategies were discussed. Evidence was provided that the wild-type IGF-I yields were pure by exploiting the advantages of the pHisTrx expression vector system in concert with a thrombin enzyme with its highly specific proteolytic digestion site and multiple-chromatography steps. The alkyne functionality was successfully introduced into IGF-I by amber codon suppression. The proper folding of plk-IGF-I Ea was assessed by WST-1 proliferation assay and the detection of phosphorylated AKT in MG-63 cell lysate. The purity of plk-IGF-I Ea was monitored with RP-HPLC and SDS-PAGE analysis. This work also showed site-specific coupling an alkyne in plk-IGF-I Ea by copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) with potent activities in vitro. The site-specific immobilization of plk-IGF-I Ea to the model carrier (i.e., agarose beads) resulted in enhanced cell proliferation and adhesion surrounding the IGF-I-presenting particles. Cell proliferation and differentiation were enhanced in the accessibility of IGF-I decorated beads, reflecting the multivalence on cellular performance. Next, we aimed at effectively showing the disease environment by co-delivery of fibroblast growth factor 2 (FGF2) and IGF-I, deploying localized matrix metalloproteinases (MMPs) upregulation as a surrogate marker driving the response of the drug delivery system. For this purpose, we genetically engineered FGF2 variant containing an (S)-2-amino-6-(((2-azidoethoxy)carbonyl)amino)hexanoic acid incorporated at its N-terminus, followed by an MMPs-cleavable linker (PCL) and FGF2 sequence, thereby allowing site-directed, specific decoration of the resultant azide-PCL-FGF2 with the previously mentioned plk-IGF-I Ea to generate defined protein-protein conjugates with a PCL in between. The click reaction between plk-IGF-I Ea and azide-PCL-FGF2 was systematically optimized to increase the yield of IGF-FGF conjugates, including reaction temperature, incubation duration, the addition of anionic detergent, and different ratios of the participating biopharmaceutics. The challenge here was that CuAAC reaction components or conditions might oxidize free cysteines of azide-PCL-FGF2 and future work needs to present the extent of activity retention after conjugation. Furthermore, our study provides potential options for dual-labeling of IGF-I either by the introduction of unnatural amino acids within two distinct positions of the protein of interest for parallel "double-click" labeling of the resultant plk-IGF-I Ea-plk or by using a combination of enzymatic-catalyzed and CuAAC bioorthogonal coupling strategies for sequentially dual-labeling of plk-IGF-I Ea. In conclusion, genetic code expansion in combination with click-chemistry provides the fundament for novel IGF-I analogs allowing unprecedented site specificity for decoration. Considerable progress towards IGF-I based therapies with enhanced pharmacological properties was made by demonstrating the feasibility of the expression of plk incorporated IGF-I using E. coli and retained activity of unconjugated and conjugated IGF-I variant. Dual-labeling of IGF-I provides further insights into the functional requirements of IGF-I. Still, further investigation warrants to develop precise IGF-I therapy through unmatched temporal and spatial regulation of the pleiotropic IGF-I.}, subject = {Insulin-like Growth Factor I}, language = {en} } @phdthesis{Gulve2019, author = {Gulve, Nitish}, title = {Subversion of Host Genome Integrity by Human Herpesvirus 6 and \(Chlamydia\) \(trachomatis\)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-162026}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Ovarian cancer is one of the most common gynecological malignancies in the world. The prevalence of a microbial signature in ovarian cancer has been reported by several studies till date. In these microorganisms, Human herpesvirus 6 (HHV-6) and Chlamydia trachomatis (C.tr) are especially important as they have significantly high prevalence rate. Moreover, these pathogens are directly involved in causing DNA damage and thereby disrupting the integrity of host genome which is the underlying cause of any cancer. This study focuses on how the two pathogens, HHV-6 and C. trachomatis can affect the genome integrity in their individual capacities and thereby may drive ovarian epithelial cells towards transformation. HHV-6 has unique tendency to integrate its genome into the host genome at subtelomeric regions and achieve a state of latency. This latent virus may get reactivated during the course of life by stress, drugs such as steroids, during transplantation, pregnancy etc. The study presented here began with an interesting observation wherein the direct repeat (DR) sequences flanking the ends of double stranded viral genome were found in unusually high numbers in human blood samples as opposed to normal ratio of two DR copies per viral genome. This study was corroborated with in vitro data where cell lines were generated to mimic the HHV-6 status in human samples. The same observation of unusually high DR copies was found in these cell lines as well. Interestingly, fluorescence in situ hybridization (FISH) and inverse polymerase chain reaction followed by southern blotting showed that DR sequences were found to be integrated in nontelomeric regions as opposed to the usual sub-telomeric integration sites in both human samples and in cell lines. Sanger sequencing confirmed the non-telomeric integration of viral DR sequences in the host genome. Several studies have shown that C. trachomatis causes DNA damage and inhibits the signaling cascade of DNA damage response. However, the effect of C. trachomatis infection on process of DNA repair itself was not addressed. In this study, the effect of C. trachomatis infection on host base excision repair (BER) has been addressed. Base excision repair is a pathway which is responsible for replacing the oxidized bases with new undamaged ones. Interestingly, it was found that C. trachomatis infection downregulated polymerase β expression and attenuated polymerase β- mediated BER in vitro. The mechanism of the polymerase β downregulation was found to be associated with the changes in the host microRNAs and downregulation of tumor suppressor, p53. MicroRNA-499 which has a binding site in the polymerase β 3'UTR was shown to be upregulated during C. trachomatis infection. Inhibition of miR-499 using synthetic miR-499 inhibitor indeed improved the repair efficiency during C. trachomatis infection in the in vitro repair assay. Moreover, p53 transcriptionally regulates polymerase β and stabilizing p53 during C. trachomatis infection enhanced the repair efficiency. Previous studies have shown that C. trachomatis can reactivate latent HHV-6. Therefore, genomic instability due to insertions of unstable 'transposon-like' HHV-6 DR followed by compromised BER during C. trachomatis infection cumulatively support the hypothesis of pathogenic infections as a probable cause of ovarian cancer}, subject = {Chlamydia trachomatis}, language = {en} }