@phdthesis{Franke2019, author = {Franke, Christian}, title = {Advancing Single-Molecule Localization Microscopy: Quantitative Analyses and Photometric Three-Dimensional Imaging}, doi = {10.25972/OPUS-15635}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-156355}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Since its first experimental implementation in 2005, single-molecule localization microscopy (SMLM) emerged as a versatile and powerful imaging tool for biological structures with nanometer resolution. By now, SMLM has compiled an extensive track-record of novel insights in sub- and inter- cellular organization.\\ Moreover, since all SMLM techniques rely on the analysis of emission patterns from isolated fluorophores, they inherently allocate molecular information \$per\$ \$definitionem\$.\\ Consequently, SMLM transitioned from its origin as pure high-resolution imaging instrument towards quantitative microscopy, where the key information medium is no longer the highly resolved image itself, but the raw localization data set.\\ The work presented in this thesis is part of the ongoing effort to translate those \$per\$ \$se\$ molecular information gained by SMLM imaging to insights into the structural organization of the targeted protein or even beyond. Although largely consistent in their objectives, the general distinction between global or segmentation clustering approaches on one side and particle averaging or meta-analyses techniques on the other is usually made.\\ During the course of my thesis, I designed, implemented and employed numerous quantitative approaches with varying degrees of complexity and fields of application.\\ \\ In my first major project, I analyzed the localization distribution of the integral protein gp210 of the nuclear pore complex (NPC) with an iterative \textit{k}-means algorithm. Relating the distinct localization statistics of separated gp210 domains to isolated fluorescent signals led, among others, to the conclusion that the anchoring ring of the NPC consists of 8 homo-dimers of gp210.\\ This is of particular significance, both because it answered a decades long standing question about the nature of the gp210 ring and it showcased the possibility to gain structural information well beyond the resolution capabilities of SMLM by crafty quantification approaches.\\ \\ The second major project reported comprises an extensive study of the synaptonemal complex (SNC) and linked cohesin complexes. Here, I employed a multi-level meta-analysis of the localization sets of various SNC proteins to facilitate the compilation of a novel model of the molecular organization of the major SNC components with so far unmatched extend and detail with isotropic three-dimensional resolution.\\ In a second venture, the two murine cohesin components SMC3 and STAG3 connected to the SNC were analyzed. Applying an adapted algorithm, considering the disperse nature of cohesins, led to the realization that there is an apparent polarization of those cohesin complexes in the SNC, as well as a possible sub-structure of STAG3 beyond the resolution capabilities of SMLM.\\ \\ Other minor projects connected to localization quantification included the study of plasma membrane glycans regarding their overall localization distribution and particular homogeneity as well as the investigation of two flotillin proteins in the membrane of bacteria, forming clusters of distinct shapes and sizes.\\ \\ Finally, a novel approach to three-dimensional SMLM is presented, employing the precise quantification of single molecule emitter intensities. This method, named TRABI, relies on the principles of aperture photometry which were improved for SMLM.\\ With TRABI it was shown, that widely used Gaussian fitting based localization software underestimates photon counts significantly. This mismatch was utilized as a \$z\$-dependent parameter, enabling the conversion of 2D SMLM data to a virtual 3D space. Furthermore it was demonstrated, that TRABI can be combined beneficially with a multi-plane detection scheme, resulting in superior performance regarding axial localization precision and resolution.\\ Additionally, TRABI has been subsequently employed to photometrically characterize a novel dye for SMLM, revealing superior photo-physical properties at the single-molecule level.\\ Following the conclusion of this thesis, the TRABI method and its applications remains subject of diverse ongoing research.}, subject = {Einzelmolek{\"u}lmikroskopie}, language = {en} } @article{KasaragodSchindelin2019, author = {Kasaragod, Vikram Babu and Schindelin, Hermann}, title = {Structure of Heteropentameric GABAA Receptors and Receptor-Anchoring Properties of Gephyrin}, series = {Frontiers in Molecular Neuroscience}, volume = {12}, journal = {Frontiers in Molecular Neuroscience}, issn = {1662-5099}, doi = {10.3389/fnmol.2019.00191}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-189308}, pages = {191}, year = {2019}, abstract = {γ-Aminobutyric acid type A receptors (GABAARs) mediate the majority of fast synaptic inhibition in the central nervous system (CNS). GABAARs belong to the Cys-loop superfamily of pentameric ligand-gated ion channels (pLGIC) and are assembled from 19 different subunits. As dysfunctional GABAergic neurotransmission manifests itself in neurodevelopmental disorders including epilepsy and anxiety, GABAARs are key drug targets. The majority of synaptic GABAARs are anchored at the inhibitory postsynaptic membrane by the principal scaffolding protein gephyrin, which acts as the central organizer in maintaining the architecture of the inhibitory postsynaptic density (iPSD). This interaction is mediated by the long intracellular loop located in between transmembrane helices 3 and 4 (M3-M4 loop) of the receptors and a universal receptor-binding pocket residing in the C-terminal domain of gephyrin. In 2014, the crystal structure of the β3-homopentameric GABAAR provided crucial information regarding the architecture of the receptor; however, an understanding of the structure and assembly of heteropentameric receptors at the atomic level was lacking. This review article will highlight recent advances in understanding the structure of heteropentameric synaptic GABAARs and how these structures have provided fundamental insights into the assembly of these multi-subunit receptors as well as their modulation by diverse ligands including the physiological agonist GABA. We will further discuss the role of gephyrin in the anchoring of synaptic GABAARs and glycine receptors (GlyRs), which are crucial for maintaining the architecture of the iPSD. Finally, we will also summarize how anti-malarial artemisinin drugs modulate gephyrin-mediated inhibitory neurotransmission.}, language = {en} } @phdthesis{Schuberth2019, author = {Schuberth, Florian}, title = {Composite-based Methods in Structural Equation Modeling}, doi = {10.25972/OPUS-15465}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-154653}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {This dissertation deals with composite-based methods for structural equation models with latent variables and their enhancement. It comprises five chapters. Besides a brief introduction in the first chapter, the remaining chapters consisting of four essays cover the results of my PhD studies.Two of the essays have already been published in an international journal. The first essay considers an alternative way of construct modeling in structural equation modeling.While in social and behavioral sciences theoretical constructs are typically modeled as common factors, in other sciences the common factor model is an inadequate way construct modeling due to its assumptions. This essay introduces the confirmatory composite analysis (CCA) analogous to confirmatory factor analysis (CFA). In contrast to CFA, CCA models theoretical constructs as composites instead of common factors. Besides the theoretical presentation of CCA and its assumptions, a Monte Carlo simulation is conducted which demonstrates that misspecifications of the composite model can be detected by the introduced test for overall model fit. The second essay rises the question of how parameter differences can be assessed in the framework of partial least squares path modeling. Since the standard errors of the estimated parameters have no analytical closed-form, the t- and F-test known from regression analysis cannot be directly used to test for parameter differences. However, bootstrapping provides a solution to this problem. It can be employed to construct confidence intervals for the estimated parameter differences, which can be used for making inferences about the parameter difference in the population. To guide practitioners, guidelines were developed and demonstrated by means of empirical examples. The third essay answers the question of how ordinal categorical indicators can be dealt with in partial least squares path modeling. A new consistent estimator is developed which combines the polychoric correlation and partial least squares path modeling to appropriately deal with the qualitative character of ordinal categorical indicators. The new estimator named ordinal consistent partial least squares combines consistent partial least squares with ordinal partial least squares. Besides its derivation, a Monte Carlo simulation is conducted which shows that the new estimator performs well in finite samples. Moreover, for illustration, an empirical example is estimated by ordinal consistent partial least squares. The last essay introduces a new consistent estimator for polynomial factor models. Similarly to consistent partial least squares, weights are determined to build stand-ins for the latent variables, however a non-iterative approach is used. A Monte Carlo simulation shows that the new estimator behaves well in finite samples.}, subject = {Strukturgleichungsmodell}, language = {en} } @article{ZhangZhengZhengetal.2019, author = {Zhang, Yonghong and Zheng, Lanlan and Zheng, Yan and Zhou, Chao and Huang, Ping and Xiao, Xiao and Zhao, Yongheng and Hao, Xincai and Hu, Zhubing and Chen, Qinhua and Li, Hongliang and Wang, Xuanbin and Fukushima, Kenji and Wang, Guodong and Li, Chen}, title = {Assembly and Annotation of a Draft Genome of the Medicinal Plant Polygonum cuspidatum}, series = {Frontiers in Plant Science}, volume = {10}, journal = {Frontiers in Plant Science}, issn = {1664-462X}, doi = {10.3389/fpls.2019.01274}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-189279}, pages = {1274}, year = {2019}, abstract = {Polygonum cuspidatum (Japanese knotweed, also known as Huzhang in Chinese), a plant that produces bioactive components such as stilbenes and quinones, has long been recognized as important in traditional Chinese herbal medicine. To better understand the biological features of this plant and to gain genetic insight into the biosynthesis of its natural products, we assembled a draft genome of P. cuspidatum using Illumina sequencing technology. The draft genome is ca. 2.56 Gb long, with 71.54\% of the genome annotated as transposable elements. Integrated gene prediction suggested that the P. cuspidatum genome encodes 55,075 functional genes, including 6,776 gene families that are conserved in the five eudicot species examined and 2,386 that are unique to P. cuspidatum. Among the functional genes identified, 4,753 are predicted to encode transcription factors. We traced the gene duplication history of P. cuspidatum and determined that it has undergone two whole-genome duplication events about 65 and 6.6 million years ago. Roots are considered the primary medicinal tissue, and transcriptome analysis identified 2,173 genes that were expressed at higher levels in roots compared to aboveground tissues. Detailed phylogenetic analysis demonstrated expansion of the gene family encoding stilbene synthase and chalcone synthase enzymes in the phenylpropanoid metabolic pathway, which is associated with the biosynthesis of resveratrol, a pharmacologically important stilbene. Analysis of the draft genome identified 7 abscisic acid and water deficit stress-induced protein-coding genes and 14 cysteine-rich transmembrane module genes predicted to be involved in stress responses. The draft de novo genome assembly produced in this study represents a valuable resource for the molecular characterization of medicinal compounds in P. cuspidatum, the improvement of this important medicinal plant, and the exploration of its abiotic stress resistance.}, language = {en} } @phdthesis{Derakhshani2019, author = {Derakhshani, Shaghayegh}, title = {Measles virus infection enhances dendritic cell migration in a 3D environment}, doi = {10.25972/OPUS-18918}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-189182}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The respiratory system is amongst the most important compartments in the human body. Due to its connection to the external environment, it is one of the most common portals of pathogen entry. Airborne pathogens like measles virus (MV) carried in liquid droplets exhaled from the infected individuals via a cough or sneeze enter the body from the upper respiratory tract and travel down to the lower respiratory tract and reach the alveoli. There, pathogens are captured by the resident dendritic cells (DCs) or macrophages and brought to the lymph node where immune responses or, as in case of MV, dissemination via the hematopoietic cell compartment are initiated. Basic mechanisms governing MV exit from the respiratory tract, especially virus transmission from infected immune cells to the epithelial cells have not been fully addressed before. Considering the importance of these factors in the viral spread, a complex close-to-in-vivo 3D human respiratory tract model was generated. This model was established using de-cellularized porcine intestine tissue as a biological scaffold and H358 cells as targets for infection. The scaffold was embedded with fibroblast cells, and later on, an endothelial cell layer seeded at the basolateral side. This provided an environment resembling the respiratory tract where MV infected DCs had to transmigrate through the collagen scaffold and transmit the virus to epithelial cells in a Nectin-4 dependent manner. For viral transmission, the access of infected DCs to the recipient epithelial cells is an essential prerequisite and therefore, this important factor which is reflected by cell migration was analyzed in this 3D system. The enhanced motility of specifically MV-infected DCs in the 3D models was observed, which occurred independently of factors released from the other cell types in the models. Enhanced motility of infected DCs in 3D collagen matrices suggested infection-induced cytoskeletal remodeling, as also verified by detection of cytoskeletal polarization, uropod formation. This enforced migration was sensitive to ROCK inhibition revealing that MV infection induces an amoeboid migration mode in DCs. In support of this, the formation of podosome structures and filopodia, as well as their activity, were reduced in infected DCs and retained in their uninfected siblings. Differential migration modes of uninfected and infected DCs did not cause differential maturation, which was found to be identical for both populations. As an underlying mechanism driving this enforced migration, the role of sphingosine kinase (SphK) and sphingosine-1-phosphate (S1P) was studied in MV-exposed cultures. It was shown in this thesis that MV-infection increased S1P production, and this was identified as a contributing factor as inhibition sphingosine kinase activity abolished enforced migration of MV-infected DCs. These findings revealed that MV infection induces a fast push-and-squeeze amoeboid mode of migration, which is supported by SphK/S1P axis. However, this push-and-squeeze amoeboid migration mode did not prevent the transendothelial migration of MV-infected DCs. Altogether, this 3D system has been proven to be a suitable model to study specific parameters of mechanisms involved in infections in an in vivo-like conditions.}, subject = {Dendritische Zelle}, language = {en} } @phdthesis{TshitengeTshitenge2019, author = {Tshitenge Tshitenge, Dieudonn{\´e}}, title = {Isolation and Structural Elucidation of Novel Anti-Infective Naphthylisoquinoline Alkaloids from Ancistrocladus ealaensis, and Phytochemical Analysis of Two Congolese Medicinal Plants}, doi = {10.25972/OPUS-15417}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-154175}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Herein described are the isolation, structural elucidation, and biological evaluation of highly thrilling monomeric and dimeric new naphthylisoquinoline alkaloids from A. ealaensis. The separation, chiral resolution, and characterization of a series of stereoisomeric 2,3-dihydrobenzofuran neolignans are also reported. The analytical and phytochemical analysis on two Congolese antimalarial herbal drugs is part of the last chapter of the results. In this last case, major concerns on widely used Congolese herbal drugs are discussed.}, subject = {Naphthylisochinolinalkaloide}, language = {en} } @phdthesis{RamirezPasos2019, author = {Ramirez Pasos, Uri Eduardo}, title = {Subthalamic Nucleus Neural Synchronization and Connectivity during Limbic Processing of Emotional Pictures: Evidence from Invasive Recordings in Patients with Parkinson's Disease}, doi = {10.25972/OPUS-16985}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169850}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {In addition to bradykinesia and tremor, patients with Parkinson's disease (PD) are known to exhibit non-motor symptoms such as apathy and hypomimia but also impulsivity in response to dopaminergic replacement therapy. Moreover, a plethora of studies observe differences in electrocortical and autonomic responses to both visual and acoustic affective stimuli in PD subjects compared to healthy controls. This suggests that the basal ganglia (BG), as well as the hyperdirect pathway and BG thalamocortical circuits, are involved in affective processing. Recent studies have shown valence and dopamine-dependent changes in synchronization in the subthalamic nucleus (STN) in PD patients during affective tasks. This thesis investigates the role of dopamine, valence, and laterality in STN electrophysiology by analyzing event-related potentials (ERP), synchronization, and inter-hemispheric STN connectivity. STN recordings were obtained from PD patients with chronically implanted electrodes for deep brain stimulation during a passive affective picture presentation task. The STN exhibited valence-dependent ERP latencies and lateralized 'high beta' (28-40 Hz) event-related desynchronization. This thesis also examines the role of dopamine, valence, and laterality on STN functional connectivity with the anterior cingulate cortex (ACC) and the amygdala. The activity of these limbic structures was reconstructed using simultaneously recorded electroencephalographic signals. While the STN was found to establish early coupling with both structures, STN-ACC coupling in the 'alpha' range (7-11 Hz) and uncoupling in the 'low beta' range (14-21 Hz) were lateralized. Lateralization was also observed at the level of synchrony in both reconstructed sources and for ACC ERP amplitude, whereas dopamine modulated ERP latency in the amygdala. These results may deepen our current understanding of the STN as a limbic node within larger emotional-motor networks in the brain.
}, subject = {Nucleus subthalamicus}, language = {en} } @phdthesis{Loeffler2019, author = {L{\"o}ffler, Mona Christina}, title = {Protein kinase D1 deletion in adipocytes enhances energy dissipation and protects against adiposity}, doi = {10.25972/OPUS-18859}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-188593}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Adaptation to alterations in nutrient availability ensures the survival of organisms. In vertebrates, adipocytes play a decisive role in this process due to their ability to store large amounts of excess nutrients and release them in times of food deprivation. In todays western world, a rather unlimited excess of nutrients leads to high-caloric food consumption in humans. Nutrient overload together with a decreased energy dissipation result in obesity as well as associated diseases such as insulin resistance, diabetes, and liver steatosis. Obesity causes a hormonal imbalance, which in combination with altered nutrient levels can aberrantly activate G-protein coupled receptors utilizing diacylglycerol (DAG) as secondary messenger. Protein kinase D (PKD) 1 is a DAG effector integrating multiple hormonal and nutritional inputs. Nevertheless, its physiological role in adipocytes has not been investigated so far. In this thesis, evidence is provided that the deletion of PKD1 in adipocytes suppresses lipogenesis as well as the accumulation of triglycerides. Furthermore, PKD1 depletion results in increased mitochondrial biogenesis as well as decoupling activity. Moreover, PKD1 deletion promotes the expression of the β3-adrenergic receptor (ADRB3) in a CCAAT/enhancer-binding protein (C/EBP)-α and δ-dependent manner. This results in elevated expression levels of beige markers in adipocytes in the presence of a β-agonist. Contrarily, adipocytes expressing a constitutive active form of PKD1 present a reversed phenotype. Additionally, PKD1 regulates adipocyte metabolism in an AMP-activated protein kinase (AMPK)-dependent manner by suppressing its activity through phosphorylation of AMPK α1/α2 subunits. Thus, PKD1 deletion results in an enhanced activity of the AMPK complex. Consistent with the in vitro findings, mice lacking PKD1 in adipocytes demonstrate a resistance to high-fat diet-induced obesity due to an elevated energy expenditure caused by trans-differentiation of white into beige adipocytes. Moreover, deletion of PKD1 in murine adipocytes improves systemic insulin sensitivity and ameliorates liver steatosis. Finally, PKD1 levels positively correlate with HOMA-IR as well as insulin levels in human subjects. Furthermore, inhibition of PKD1 in human adipocytes leads to metabolic alterations, which are comparable to the alterations seen in their murine counterparts. Taken together, these data demonstrate that PKD1 suppresses energy dissipation, drives lipogenesis, and adiposity. Therefore, increased energy dissipation induced by several complementary mechanisms upon PKD1 deletion might represent an attractive strategy to treat obesity and its related complications.}, subject = {Proteinkinase D}, language = {en} } @phdthesis{Eckstein2019, author = {Eckstein, Klaus}, title = {Linear and Nonlinear Spectroscopy of Doped Carbon Nanotubes}, doi = {10.25972/OPUS-18897}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-188975}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Doping plays a decisive role for the functionality of semiconductor-based (opto-)electronic devices. Hence, the technological utilization of semiconductors necessitates control and a fundamental understanding of the doping process. However, for low-dimensional systems like carbon nanotubes, neither concentration nor distribution of charge carriers is currently well known. The research presented in this thesis investigated the doping of semiconducting carbon nanotubes by spectroscopic methods. Samples of highly purified, intrinsic (6,5) single-wall carbon nanotubes were fabricated using polymer stabilization. Chapter 4 showed that both electro- and redox chemical \$p\$-doping lead to identical bleaching, blueshift, broadening and asymmetry of the S\$_1\$ exciton absorption band. The similar spectral changes induced by both doping schemes suggest that optical spectra can not be used to infer what process was used for doping. Perhaps more importantly, it also indicates that the distribution of charges and the character of the charge transfer states does not depend on the method by which doping was achieved. The detailed analysis of the doping-induced spectral changes in chapter 5 suggests that surplus charges are distributed inhomogeneously. The hypothesis of carrier localization is consistent with the high sensitivity of the S\$_1\$ exciton photoluminescence to additional charge carriers and with the stretched-exponential decay of the exciton population following ultrafast excitation. Both aspects are in good agreement with diffusion-limited contact quenching of excitons at localized charges. Moreover, localized charges act - similar to structural defects - as perturbations to the bandstructure as evidenced by a doping-induced increase of the D-band antiresonance in the mid-infrared spectrum. Quantum mechanical model calculations also suggest that counterions play a crucial role in carrier localization. Counterion adsorption at the nanotube surface is thus believed to induce charge traps of more than 100 meV depth with a carrier localization length on the order of 3 - 4 nm. The doping-induced bleach of interband absorption is accompanied by an absorption increase in the IR region below 600 meV. The observed shift of the IR peak position indicates a continuous transition from localized to rather delocalized charge carriers. This transition is caused by the increase of the overlap of charge carrier wavefunctions at higher charge densities and was modeled by classical Monte-Carlo simulations of intraband absorption. Chapter 6 discussed the spectroscopy of heavily (degenerately) doped nanotubes, which are characterized by a Drude-response of free-carrier intraband absorption in the optical conductivity spectrum. In the NIR spectral region, the S\$_1\$ exciton and X\$+^_1\$ trion absorption is replaced by a nearly 1 eV broad and constant absorption signal, the so-called H-band. The linear and transient absorption spectra of heavily doped nanotubes suggest that the H-band can be attributed to free-carrier interband transitions. Chapter 7 dealt with the quantification of charge carrier densities by linear absorption spectroscopy. A particularly good measure of the carrier density is the S\$_1\$ exciton bleach. For a bleach below about 50 \%, the carrier density is proportional to the bleach. At higher doping levels, deviations from the linear behavior were observed. For doping levels exceeding a fully bleached S\$_1\$ band, the determination of the normalized oscillator strength f\$\text{1st}\$ over the whole first subband region (trion, exciton, free e-h pairs) is recommended for quantification of carrier densities. Based on the nanotube density of states, the carrier density \$n\$ can be estimated using \$n = 0.74\,\text{nm}^{-1} \cdot (1 - f_\text{1st})\$. In the last part of this thesis (chapter 8), the time-resolved spectroelectrochemistry was extended to systems beyond photostable carbon nanotube films. The integration of a flowelectrolysis cell into the transient absorption spectrometer allows the investigation of in-situ electrochemically generated but photounstable molecules due to a continuous exchange of sample volume. First time-resolved experiments were successfully performed using the dye methylene blue and its electrochemically reduced form leucomethylene blue.}, subject = {Dotierung}, language = {en} } @unpublished{BruecknerStennettHessetal.2019, author = {Br{\"u}ckner, Tobias and Stennett, Tom E. and Heß, Merlin and Braunschweig, Holger}, title = {Single and Double Hydroboration of B-B Triple Bonds and Conver- gent Routes to a Cationic Tetraborane}, series = {Journal of the American Chemical Society}, journal = {Journal of the American Chemical Society}, doi = {10.1021/jacs.9b07991}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-188632}, year = {2019}, abstract = {A compound with a boron-boron triple bond is shown to undergo stepwise hydroboration reactions with catecholborane to yield an unsymmetrical hydro(boryl)diborene and a 2,3-dihydrotetraborane. Abstraction of H- from the latter compound produces an unusual cationic, planar tetraborane with a hydrogen atom bridging the central B2 moiety. Spectroscopic and crystallographic data and DFT calculations support a 'protonated diborene' structure for this compound, which can also be accessed via direct protonation of the corresponding diborene.}, language = {en} } @phdthesis{Gomes2019, author = {Gomes, Sara Ferreira Martins}, title = {Induced Pluripotent Stem Cell-derived Brain Endothelial Cells as a Cellular Model to Study Neisseria meningitidis Infection}, doi = {10.25972/OPUS-18855}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-188550}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Bacterial meningitis occurs when blood-borne bacteria are able to penetrate highly specialized brain endothelial cells (BECs) and gain access to the meninges. Neisseria meningitidis (Nm) is a human-exclusive pathogen for which suitable in vitro models are severely lacking. Until recently, modeling BEC-Nm interactions has been almost exclusively limited to immortalized human cells that lack proper BEC phenotypes. Specifically, these in vitro models lack barrier properties, and continuous tight junctions. Alternatively, humanized mice have been used, but these must rely on known interactions and have limited translatability. This motivates the need to establish novel human-based in vitro BEC models that have barrier phenotypes to research Nm-BEC interactions. Recently, a human induced pluripotent stem cell (iPSC) model of BECs has been developed that possesses superior BEC phenotypes and closely mimics the in vivo blood vessels present at the blood-meningeal barrier. Here, iPSC-BECs were tested as a novel cellular model to study Nm-host pathogen interactions, with focus on host responses to Nm infection. Two wild type strains and three mutant strains of Nm were used to confirm that these followed similar phenotypes to previously described models. Importantly, the recruitment of the recently published pilus adhesin receptor CD147 underneath meningococcal microcolonies could be verified in iPSC-BECs. Nm was also observed to significantly increase the expression of pro-inflammatory and neutrophil-specific chemokines IL6, CXCL1, CXCL2, CXCL8, and CCL20, at distinct time points of infection, and the secretion of IFN γ and RANTES by iPSC-BECs. Nm was directly observed to disrupt tight junction proteins ZO-1, Occludin, and Claudin-5 at late time points of infection, which became frayed and/or discontinuous upon infection. This destruction is preceded by, and might be dependent on, SNAI1 activation (a transcriptional repressor of tight junction proteins). In accordance with tight junction loss, a sharp loss in trans-endothelial electrical resistance, and an increase in sodium fluorescein permeability was observed at late infection time points. Notably, bacterial transmigration correlated with junctional disruption, indicating that the paracellular route contributes for bacterial crossing of BECs. Finally, RNA-Sequencing (RNA-Seq) of sorted, infected iPSC-BECs was established through the use of fluorescence-activated cell sorting (FACS) techniques following infection. This allowed the detection of expression data of Nm-responsive host genes not previously described thus far to play a role during meningitidis. In conclusion, here the utility of iPSC-BECs in vitro to study Nm infection could be demonstrated. This is the first BEC in vitro model to express all major BEC tight junctions and to display high barrier potential. Altogether, here this model provides novel insights into Nm pathogenesis, including an impact of Nm on barrier properties and tight junction complexes and suggests that the paracellular route contributes to Nm traversal of BECs.}, subject = {Neisseria meningitidis}, language = {en} } @phdthesis{Rubo2019, author = {Rubo, Marius}, title = {Social Attention in the Laboratory, in Real Life and in Virtual Reality}, doi = {10.25972/OPUS-18845}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-188452}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Social attention is a ubiquitous, but also enigmatic and sometimes elusive phenomenon. We direct our gaze at other human beings to see what they are doing and to guess their intentions, but we may also absorb social events en passant as they unfold in the corner of the eye. We use our gaze as a discrete communication channel, sometimes conveying pieces of information which would be difficult to explicate, but we may also find ourselves avoiding eye-contact with others in moments when self-disclosure is fear-laden. We experience our gaze as the most genuine expression of our will, but research also suggests considerable levels of predictability and automaticity in our gaze behavior. The phenomenon's complexity has hindered researchers from developing a unified framework which can conclusively accommodate all of its aspects, or from even agreeing on the most promising research methodologies. The present work follows a multi-methods approach, taking on several aspects of the phenomenon from various directions. Participants in study 1 viewed dynamic social scenes on a computer screen. Here, low-level physical saliency (i.e. color, contrast, or motion) and human heads both attracted gaze to a similar extent, providing a comparison of two vastly different classes of gaze predictors in direct juxtaposition. In study 2, participants with varying degrees of social anxiety walked in a public train station while their eye movements were tracked. With increasing levels of social anxiety, participants showed a relative avoidance of gaze at near compared to distant people. When replicating the experiment in a laboratory situation with a matched participant group, social anxiety did not modulate gaze behavior, fueling the debate around appropriate experimental designs in the field. Study 3 employed virtual reality (VR) to investigate social gaze in a complex and immersive, but still highly controlled situation. In this situation, participants exhibited a gaze behavior which may be more typical for real-life compared to laboratory situations as they avoided gaze contact with a virtual conspecific unless she gazed at them. This study provided important insights into gaze behavior in virtual social situations, helping to better estimate the possible benefits of this new research approach. Throughout all three experiments, participants showed consistent inter-individual differences in their gaze behavior. However, the present work could not resolve if these differences are linked to psychologically meaningful traits or if they instead have an epiphenomenal character.}, subject = {Aufmerksamkeit}, language = {en} } @phdthesis{Gerner2019, author = {Gerner, Frank}, title = {Functional analysis of polarization and podosome formation of murine and human megakaryocytes}, doi = {10.25972/OPUS-16050}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-160508}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {In mammals, blood platelets are produced by large bone marrow (BM) precursor cells, megakaryocytes (MK) that extend polarized cell protrusions (proplateles) into BM sinusoids. Proplatelet formation (PPF) requires substantial cytoskeletal rearrangements that have been shown to involve the formation of podosomes, filamentous actin (F-actin) and integrin-rich structures. However, the exact molecular mechanisms regulating MK podosome formation, polarization and migration within the BM are poorly defined. According to current knowledge obtained from studies with other cell types, these processes are regulated by Rho GTPase proteins like RhoA and Cdc42. In this thesis, polarization and podosome formation were investigated in MKs from genetically modified mice, as well as the cell lines K562 and Meg01 by pharmacological modulation of signaling pathways. The first part of this thesis describes establishment of the basic assays for investigation of MK polarization. Initial data on polarization of the MK-like erythroleukemia cell line K562 revealed first insights into actin and tubulin dynamics of wild type (WT) and RhoA knock-out (RhoA-/-) K562 cells. Phorbol 12-myristate 13-acetate (PMA)-induction of K562 cells led to the expected MK-receptor upregulation but also RhoA depletion and altered polarization patterns. The second part of this thesis focuses on podosome formation of MKs. RhoA is shown to be dispensable for podosome formation. Cdc42 is revealed as an important, but not essential regulator of MK spreading and podosome formation. Studies of signaling pathways of podosome formation reveal the importance of the tyrosine kinases Src, Syk, as well as glycoprotein (GP)VI in MK spreading and podosome formation. This thesis provides novel insights into the mechanisms underlying polarization and podosome formation of MKs and reveals new, important information about cytoskeletal dynamics of MKs and potentially also platelets.}, subject = {Megakaryozyt}, language = {en} } @phdthesis{Bathon2019, author = {Bathon, Kerstin}, title = {Mutations in protein kinase A catalytic subunit as a cause of adrenal Cushing's syndrome: mechanisms and functional consequences}, doi = {10.25972/OPUS-16893}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-168937}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Protein kinase A (PKA) is the main effector of cyclic-adenosine monophosphate (cAMP) and plays an important role in steroidogenesis and proliferation of adrenal cells. In a previous study we found two mutations (L206R, 199_200insW) in the main catalytic subunit of protein kinase A (PKA C) to be responsible for cortisol-producing adrenocortical adenomas (CPAs). These mutations interfere with the formation of a stable holoenzyme, thus causing constitutive PKA activation. More recently, we identified additional mutations affecting PKA C in CPAs associated with overt Cushing syndrome: S213R+insIILR, 200_201insV, W197R, d244 248+E249Q, E32V. This study reports a functional characterization of those PKA Cmutations linked to CPAs of Cushing's patients. All analyzed mutations except for E32V showed a reduced interaction with at least one tested regulatory (R) subunit. Interestingly the results of the activity differed among the mutants and between the assays employed. For three mutants (L206R, 199_200insW, S213R+insIILR), the results showed enhanced translocation to the nucleus. This was also observed in CRISPR/Cas9 generated PRKACA L206R mutated HEK293T cells. The enhanced nuclear translocation of this mutants could be due to the lack of R subunit binding, but also other mechanisms could be at play. Additionally, I used an algorithm, which predicted an effect of the mutation on substrate specificity for four mutants (L206R, 199_200insW, 200_201insV, d244 248+E249Q). This was proven using phosphoproteomics for three mutants (L206R, 200_201insV, d244 248+E249Q). In PRKACA L206R mutated CPAs this change in substrate specificity also caused hyperphosphorylation of H1.4 on serine 36, which has been reported to be implicated in mitosis. Due to these observations, I hypothesized, that there are several mechanisms of action of PRKACA mutations leading to increased cortisol secretion and cell proliferation in adrenal cells: interference with the formation of a stable holoenzyme, altered subcellular localization and a change in substrate specificity. My data indicate that some PKA C mutants might act via just one, others by a combination of these mechanisms. Altogether, these findings indicate that several mechanisms contribute to the development of CPAs caused by PRKACA mutations. Moreover, these findings provide a highly illustrative example of how alterations in a protein kinase can cause a human disease.}, subject = {Proteinkinase A}, language = {en} } @phdthesis{WeinstockgebPattschull2019, author = {Weinstock [geb. Pattschull], Grit}, title = {Crosstalk between the MMB complex and YAP in transcriptional regulation of cell cycle genes}, doi = {10.25972/OPUS-17086}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170866}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The Myb-MuvB (MMB) multiprotein complex is a master regulator of cell cycle-dependent gene expression. Target genes of MMB are expressed at elevated levels in several different cancer types and are included in the chromosomal instability (CIN) signature of lung, brain, and breast tumors. This doctoral thesis showed that the complete loss of the MMB core subunit LIN9 leads to strong proliferation defects and nuclear abnormalities in primary lung adenocarcinoma cells. Transcriptome profiling and genome-wide DNA-binding analyses of MMB in lung adenocarcinoma cells revealed that MMB drives the expression of genes linked to cell cycle progression, mitosis, and chromosome segregation by direct binding to promoters of these genes. Unexpectedly, a previously unknown overlap between MMB-dependent genes and several signatures of YAP-regulated genes was identified. YAP is a transcriptional co-activator acting downstream of the Hippo signaling pathway, which is deregulated in many tumor types. Here, MMB and YAP were found to physically interact and co-regulate a set of mitotic and cytokinetic target genes, which are important in cancer. Furthermore, the activation of mitotic genes and the induction of entry into mitosis by YAP were strongly dependent on MMB. By ChIP-seq and 4C-seq, the genome-wide binding of MMB upon YAP overexpression was analyzed and long-range chromatin interaction sites of selected MMB target gene promoters were identified. Strikingly, YAP strongly promoted chromatin-association of B-MYB through binding to distal enhancer elements that interact with MMB-regulated promoters through chromatin looping. Together, the findings of this thesis provide a so far unknown molecular mechanism by which YAP and MMB cooperate to regulate mitotic gene expression and suggest a link between two cancer-relevant signaling pathways.}, subject = {Krebs }, language = {en} } @phdthesis{Abt2019, author = {Abt, Raimond}, title = {Implementing Aspects of Quantum Information into the AdS/CFT Correspondence}, doi = {10.25972/OPUS-18801}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-188012}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {In recent years many discoveries have been made that reveal a close relation between quantum information and geometry in the context of the AdS/CFT correspondence. In this duality between a conformal quantum field theory (CFT) and a theory of gravity on Anti-de Sitter spaces (AdS) quantum information quantities in CFT are associated with geometric objects in AdS. Subject of this thesis is the examination of this intriguing property of AdS/CFT. We study two central elements of quantum information: subregion complexity -- which is a measure for the effort required to construct a given reduced state -- and the modular Hamiltonian -- which is given by the logarithm of a considered reduced state. While a clear definition for subregion complexity in terms of unitary gates exists for discrete systems, a rigorous formulation for quantum field theories is not known. In AdS/CFT, subregion complexity is proposed to be related to certain codimension one regions on the AdS side. The main focus of this thesis lies on the examination of such candidates for gravitational duals of subregion complexity. We introduce the concept of \textit{topological complexity}, which considers subregion complexity to be given by the integral over the Ricci scalar of codimension one regions in AdS. The Gauss-Bonnet theorem provides very general expressions for the topological complexity of CFT\(_2\) states dual to global AdS\(_3\), BTZ black holes and conical defects. In particular, our calculations show that the topology of the considered codimension one bulk region plays an essential role for topological complexity. Moreover, we study holographic subregion complexity (HSRC), which associates the volume of a particular codimension one bulk region with subregion complexity. We derive an explicit field theory expression for the HSRC of vacuum states. The formulation of HSRC in terms of field theory quantities may allow to investigate whether this bulk object indeed provides a concept of subregion complexity on the CFT side. In particular, if this turns out to be the case, our expression for HSRC may be seen as a field theory definition of subregion complexity. We extend our expression to states dual to BTZ black holes and conical defects. A further focus of this thesis is the modular Hamiltonian of a family of states \(\rho_\lambda\) depending on a continuous parameter \(\lambda\). Here \(\lambda\) may be associated with the energy density or the temperature, for instance. The importance of the modular Hamiltonian for quantum information is due to its contribution to relative entropy -- one of the very few objects in quantum information with a rigorous definition for quantum field theories. The first order contribution in \(\tilde{\lambda}=\lambda-\lambda_0\) of the modular Hamiltonian to the relative entropy between \(\rho_\lambda\) and a reference state \(\rho_{\lambda_0}\) is provided by the first law of entanglement. We study under which circumstances higher order contributions in \(\tilde{\lambda}\) are to be expected. We show that for states reduced to two entangling regions \(A\), \(B\) the modular Hamiltonian of at least one of these regions is expected to provide higher order contributions in \(\tilde{\lambda}\) to the relative entropy if \(A\) and \(B\) saturate the Araki-Lieb inequality. The statement of the Araki-Lieb inequality is that the difference between the entanglement entropies of \(A\) and \(B\) is always smaller or equal to the entanglement entropy of the union of \(A\) and \(B\). Regions for which this inequality is saturated are referred to as entanglement plateaux. In AdS/CFT the relation between geometry and quantum information provides many examples for entanglement plateaux. We apply our result to several of them, including large intervals for states dual to BTZ black holes and annuli for states dual to black brane geometries.}, subject = {AdS-CFT-Korrespondenz}, language = {en} } @phdthesis{delOlmoToledo2019, author = {del Olmo Toledo, Valentina}, title = {Evolution of DNA binding preferences in a family of eukaryotic transcription regulators}, doi = {10.25972/OPUS-18789}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-187890}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Regulation of gene expression by the control of transcription is essential for any cell to adapt to the environment and survive. Transcription regulators, i.e. sequence-specific DNA binding proteins that regulate gene expression, are central elements within the gene networks of most organisms. Transcription regulators are grouped into distinct families based on structural features that determine, to a large extent, the DNA sequence(s) that they can recognise and bind. Less is known, however, about how the DNA binding preferences can diversify within transcription regulator families during evolutionary timescales, and how such diversification can affect the biology of the organism. In this dissertation I study the SREBP (sterol regulatory element binding protein) family of transcriptional regulators in yeasts, and in Candida albicans in particular, as an experimental system to address these questions. The SREBPs are conserved from fungi to humans and represent a subgroup of basic helix-loop-helix DNA binding proteins. Early chromatin immunoprecipitation experiments with SREBPs from humans and yeasts showed that these proteins bound in vivo to the canonical DNA sequence, termed E-box, most basic helix-loop-helix proteins bind to. By contrast, most recent analysis carried out with less-studied fungal SREBPs revealed a non-canonical DNA motif to be the most overrepresented sequence in the bound regions. This study aims to establish the intrinsic DNA binding preferences of key branches of this family and to determine how the divergence in DNA binding affinities originated. To this end, I combined phylogenetic and ancestral reconstruction with extensive biochemical characterisation of key SREBP proteins. The results indicated that while the most-studied SREBPs (in mammals) indeed show preference for the E-box, a second branch of the family preferentially binds the non-E-box, and a third one is able to bind both sequences with similar affinity. The preference for one or the other DNA sequence is an intrinsic property of each protein because their purified DNA binding domain was sufficient to recapitulate their in vivo binding preference. The ancestor that gave rise to these two different types of SREBPs (the branch that binds E-box and the one that binds non-E-box DNA) appears to be a protein with a broader DNA binding capability that had a slight preference for the non-canonical motif. Thus, the results imply these two branches originated by either enhancing the original ancestral preference for non-E-box or tilting it towards the E-box DNA and flipping the preference for this sequence. The main function associated with members of the SREBP family in most eukaryotes is the control of lipid biosynthesis. I have further studied the function of these proteins in the lineage that encompasses the human associated yeast C. albicans. Strikingly, the three SREBPs present in the fungus' genome contribute to the colonisation of the mammalian gut by regulating cellular processes unrelated to lipid metabolism. Here I describe that two of the three C. albicans SREBPs form a regulatory cascade that regulates morphology and cell wall modifications under anaerobic conditions, whereas the third SREBP has been shown to be involved in the regulation of glycolysis genes. Therefore, I posit that the described diversification in DNA binding specificity in these proteins and the concomitant expansion of targets of regulation were key in enabling this fungal lineage to associate with animals.}, subject = {Candida albicans}, language = {en} } @phdthesis{Du2019, author = {Du, Yiqiang}, title = {Gauge/Gravity Duality with Backreacting Background}, doi = {10.25972/OPUS-18786}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-187869}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The topic of this thesis is generalizations of the Anti de Sitter/Conformal Field Theory (AdS/CFT) correspondence, often referred to as holography, and their application to models relevant for condensed matter physics. A particular virtue of AdS/CFT is to map strongly coupled quantum field theories, for which calculations are inherently difficult, to more tractable classical gravity theories. I use this approach to study the crossover between Bose-Einstein condensation (BEC) and the Bardeen-Cooper-Schrieffer (BCS) superconductivity mechanism. I also study the phase transitions between the AdS black hole and AdS soliton spacetime in the presence of disorder. Moreover, I consider a holographic model of a spin impurity interacting with a strongly correlated electron gas, similar to the Kondo model. In AdS/CFT, the BEC/BCS crossover is modeled by a soliton configuration in the dual geometry and we study the BEC and BCS limits. The backreaction of the matter field on the background geometry is considered, which provides a new approach to study the BEC/BCS crossover. The behaviors of some physical quantities such as depletion of charge density under different strength of backreaction are presented and discussed. Moreover, the backreaction enables us to obtain the effective energy density of the soliton configurations, which together with the surface tension of the solitons leads to an argument for the occurrence of so called snake instability for dark solitons, i.e. for the solitons to form a vortex-like structures. Disordering strongly coupled and correlated quantum states of matter may lead to new insights into the physics of many body localized (MBL) strongly correlated states, which may occur in the presence of strong disorder. We are interested in potential insulator-metal transitions induced by disorder, and how disorder affects the Hawking-Page phase transition in AdS gravity in general. We introduce a metric ansatz and numerically construct the corresponding disordered AdS soliton and AdS black hole solutions, and discuss the calculation of the free energy in these states. In the Kondo effect, the rise in resistivity in metals with scarce magnetic impurities at low temperatures can be explained by the RG flow of the antiferromagnetic coupling between the impurity and conduction electrons in CFT. The generalizations to SU(N) in the large N limit make the treatment amenable to the holographic approach. We add a Maxwell term to a previously existing holographic model to study the conductivity of the itinerant electrons. Our goal is to find the log(T) behavior in the DC resistivity. In the probe limit, we introduce junction conditions to connect fields crossing the defect. We then consider backreactions, which give us a new metric ansatz and new junction conditions for the gauge fields.}, language = {en} } @phdthesis{Lundt2019, author = {Lundt, Nils}, title = {Strong light-matter coupling with 2D materials}, doi = {10.25972/OPUS-18733}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-187335}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {This publication is dedicated to investigate strong light-matter coupling with excitons in 2D materials. This work starts with an introduction to the fundamentals of excitons in 2D materials, microcavities and strong coupling in chapter 2. The experimental methods used in this work are explained in detail in chapter 3. Chapter 4 covers basic investigations that help to select appropriate materials and cavities for the following experiments. In chapter 5, results on the formation of exciton-polaritons in various materials and cavity designs are presented. Chapter 6 covers studies on the spin-valley properties of exciton-polaritons including effects such as valley polarization, valley coherence and valley-dependent polariton propagation. Finally, the formation of hybrid-polaritons and their condensation are presented in chapter 7.}, subject = {Exziton-Polariton}, language = {en} } @phdthesis{Lyutova2019, author = {Lyutova, Radostina}, title = {Functional dissection of recurrent feedback signaling within the mushroom body network of the Drosophila larva}, doi = {10.25972/OPUS-18728}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-187281}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Behavioral adaptation to environmental changes is crucial for animals' survival. The prediction of the outcome of one owns action, like finding reward or avoiding punishment, requires recollection of past experiences and comparison with current situation, and adjustment of behavioral responses. The process of memory acquisition is called learning, and the Drosophila larva came up to be an excellent model organism for studying the neural mechanisms of memory formation. In Drosophila, associative memories are formed, stored and expressed in the mushroom bodies. In the last years, great progress has been made in uncovering the anatomical architecture of these brain structures, however there is still a lack of knowledge about the functional connectivity. Dopamine plays essential roles in learning processes, as dopaminergic neurons mediate information about the presence of rewarding and punishing stimuli to the mushroom bodies. In the following work, the function of a newly identified anatomical connection from the mushroom bodies to rewarding dopaminergic neurons was dissected. A recurrent feedback signaling within the neuronal network was analyzed by simultaneous genetic manipulation of the mushroom body Kenyon cells and dopaminergic neurons from the primary protocerebral anterior (pPAM) cluster, and learning assays were performed in order to unravel the impact of the Kenyon cells-to-pPAM neurons feedback loop on larval memory formation. In a substitution learning assay, simultaneous odor exposure paired with optogenetic activation of Kenyon cells in fruit fly larvae in absence of a rewarding stimulus resulted in formation of an appetitive memory, whereas no learning behavior was observed when pPAM neurons were ablated in addition to the KC activation. I argue that the activation of Kenyon cells may induce an internal signal that mimics reward exposure by feedback activation of the rewarding dopaminergic neurons. My data further suggests that the Kenyon cells-to-pPAM communication relies on peptidergic signaling via short neuropeptide F and underlies memory stabilization.}, subject = {Lernen}, language = {en} } @phdthesis{Pahlavan2019, author = {Pahlavan, Pirasteh}, title = {Integrated Systems Biology Analysis; Exemplified on Potyvirus and Geminivirus interaction with \(Nicotiana\) \(benthamiana\)}, doi = {10.25972/OPUS-15341}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-153412}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Viral infections induce a significant impact on various functional categories of biological processes in the host. The understanding of this complex modification of the infected host immune system requires a global and detailed overview on the infection process. Therefore it is essential to apply a powerful approach which identifies the involved components conferring the capacity to recognize and respond to specific pathogens, which in general are defeated in so-called compatible virus-plant infections. Comparative and integrated systems biology of plant-virus interaction progression may open a novel framework for a systemic picture on the modulation of plant immunity during different infections and understanding pathogenesis mechanisms. In this thesis these approaches were applied to study plant-virus infections during two main viral pathogens of cassava: Cassava brown streak virus and African cassava mosaic virus. Here, the infection process was reconstructed by a combination of omics data-based analyses and metabolic network modelling, to understand the major metabolic pathways and elements underlying viral infection responses in different time series, as well as the flux activity distribution to gain more insights into the metabolic flow and mechanism of regulation; this resulted in simultaneous investigations on a broad spectrum of changes in several levels including the gene expression, primary metabolites, and enzymatic flux associated with the characteristic disease development process induced in Nicotiana benthamiana plants due to infection with CBSV or ACMV. Firstly, the transcriptome dynamics of the infected plant was analysed by using mRNA-sequencing, in order to investigate the differential expression profile according the symptom developmental stage. The spreading pattern and different levels of biological functions of these genes were analysed associated with the infection stage and virus entity. A next step was the Real-Time expression modification of selected key pathway genes followed by their linear regression model. Subsequently, the functional loss of regulatory genes which trigger R-mediated resistance was observed. Substantial differences were observed between infected mutants/transgenic lines and wild-types and characterized in detail. In addition, we detected a massive localized accumulation of ROS and quantified the scavenging genes expression in the infected wild-type plants relative to mock infected controls. Moreover, we found coordinated regulated metabolites in response to viral infection measured by using LC-MS/MS and HPLC-UV-MS. This includes the profile of the phytohormones, carbohydrates, amino acids, and phenolics at different time points of infection with the RNA and DNA viruses. This was influenced by differentially regulated enzymatic activities along the salicylate, jasmonate, and chorismate biosynthesis, glycolysis, tricarboxylic acid cycle, and pentose phosphate pathways, as well as photosynthesis, photorespiration, transporting, amino acid and fatty acid biosynthesis. We calculated the flux redistribution considering a gradient of modulation for enzymes along different infection stages, ranging from pre-symptoms towards infection stability. Collectively, our reverse-engineering study consisting of the generation of experimental data and modelling supports the general insight with comparative and integrated systems biology into a model plant-virus interaction system. We refine the cross talk between transcriptome modification, metabolites modulation and enzymatic flux redistribution during compatible infection progression. The results highlight the global alteration in a susceptible host, correlation between symptoms severity and the alteration level. In addition we identify the detailed corresponding general and specific responses to RNA and DNA viruses at different stages of infection. To sum up, all the findings in this study strengthen the necessity of considering the timing of treatment, which greatly affects plant defence against viral infection, and might result in more efficient or combined targeting of a wider range of plant pathogens.}, language = {en} } @phdthesis{Romanov2019, author = {Romanov, Natalie}, title = {Characterizing Variation of Protein Complexes and Functional Modules on a Temporal Scale and across Individuals}, doi = {10.25972/OPUS-16813}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-168139}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {A fundamental question in current biology concerns the translational mechanisms leading from genetic variability to phenotypes. Technologies have evolved to the extent that they can efficiently and economically determine an individual's genomic composition, while at the same time big data on clinical profiles and diagnostics have substantially accumulated. Genome-wide association studies linking genomic loci to certain traits, however, remain limited in their capacity to explain the cellular mechanisms that underlie the given association. For most associations, gene expression has been blamed; yet given that transcript and protein abundance oftentimes do not correlate, that finding does not necessarily decrypt the underlying mechanism. Thus, the integration of further information is crucial to establish a model that could prove more accurate in predicting genotypic effects on the human organism. In this work we describe the so-called proteotype as a feature of the cell that could provide a substantial link between genotype and phenotype. Rather than looking at the proteome as a set of independent molecules, we demonstrate a consistent modular architecture of the proteome that is driven by molecular cooperativity. Functional modules, especially protein complexes, can be further interrogated for differences between individuals and tackled as imprints of genetic and environmental variability. We also show that subtle stoichiometric changes of protein modules could have broader effects on the cellular system, such as the transport of specific molecular cargos. The presented work also delineates to what extent temporal events and processes influence the stoichiometry of protein complexes and functional modules. The re-wiring of the glycolytic pathway for example is illustrated as a potential cause for an increased Warburg effect during the ageing of the human bone marrow. On top of analyzing protein abundances we also interrogate proteome dynamics in terms of stability and solubility transitions during the short temporal progression of the cell cycle. One of our main observations in the thesis encompass the delineation of protein complexes into respective sub-complexes according to distinct stability patterns during the cell cycle. This has never been demonstrated before, and is functionally relevant for our understanding of the dis- and assembly of large protein modules. The insights presented in this work imply that the proteome is more than the sum of its parts, and primarily driven by variability in entire protein ensembles and their cooperative nature. Analyzing protein complexes and functional modules as molecular reflections of genetic and environmental variations could indeed prove to be a stepping stone in closing the gap between genotype and phenotype and customizing clinical treatments in the future.}, subject = {Proteotype}, language = {en} } @phdthesis{Goetz2019, author = {G{\"o}tz, Felix Johannes}, title = {Social Cueing of Numerical Magnitude : Observed Head Orientation Influences Number Processing}, doi = {10.25972/OPUS-18716}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-187161}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {In many parts of the modern world, numbers are used as tools to describe spatial relationships, be it heights, latitudes, or distances. However, this connection goes deeper as a myriad of studies showed that number representations are rooted in space (vertical, horizontal, and/or radial). For instance, numbers were shown to affect spatial perception and, conversely, perceptions or movements in space were shown to affect number estimations. This bidirectional link has already found didactic application in the classroom when children are taught the meaning of numbers. However, our knowledge about the cognitive (and neuropsychological) processes underlying the numerical magnitude operations is still very limited. Several authors indicated that the processing within peripersonal space (i.e. the space surrounding the body in reaching distance) and numerical magnitude operations are functionally equivalent. This assumption has several implications that the present work aims at describing. For instance, vision and visuospatial attention orienting play a prominent role for processing within peripersonal space. Indeed, both neuropsychological and behavioral studies also suggested a similar role of vision and visuospatial attention orienting for number processing. Moreover, social cognition research showed that movements, posture and gestures affect not only the representation of one's own peripersonal space, but also the visuospatial attention behavior of an observer. Against this background, the current work tests the specific implication of the functional equivalence assumption that the spatial attention response to an observed person's posture should extend to the observer's numerical magnitude operations. The empirical part of the present work tests the spatial attention response of observers to vertical head postures (with continuing eye contact to the observer) in both perceptual and numerical space. Two experimental series are presented that follow both steps from the observation of another person's vertical head orientation (within his/her peripersonal space) to the observer's attention orienting response (Experimental series A) as well as from there to the observer's magnitude operations with numbers (Experimental Series B). Results show that the observation of a movement from a neutral to a vertical head orientation (Experiment 1) as well as the observation of the vertical head orientation alone (Experiment 3) shifted the observer's spatial attention in correspondence with the direction information of the observed head (up vs. down). Movement from a vertical to a neutral end position, however, had no effect on the observer's spatial attention orienting response (Experiment 2). Furthermore, following down-tilted head posture (relative to up- or non-tilted head orientation), observers generated smaller numbers in a random number generation task (range 1- 9, Experiment 4), gave smaller estimates to numerical trivia questions (mostly multi-digit numbers, Experiment 5) and chose response keys less frequently in a free choice task that was associated with larger numerical magnitude in a intermixed numerical magnitude task. Experimental Series A served as groundwork for Experimental Series B, as it demonstrated that observing another person's head orientation indeed triggered the expected directional attention orienting response in the observer. Based on this preliminary work, the results of Experimental Series B lend support to the assumption that numerical magnitude operations are grounded in visuospatial processing of peripersonal space. Thus, the present studies brought together numerical and social cognition as well as peripersonal space research. Moreover, the Empirical Part of the present work provides the basis for elaborating on the role of processing within peripersonal space in terms of Walsh's (2003, 2013) Theory of Magnitude. In this context, a specification of the Theory of Magnitude was staked out in a processing model that stresses the pivotal role of spatial attention orienting. Implications for mental magnitude operations are discussed. Possible applications in the classroom and beyond are described.}, subject = {Soziale Wahrnehmung}, language = {en} } @phdthesis{Tian2019, author = {Tian, Yuehui}, title = {Characterization of novel rhodopsins with light-regulated cGMP production or cGMP degradation}, doi = {10.25972/OPUS-16814}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-168143}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Photoreceptors are widely occurring in almost all kingdoms of life. They mediate the first step in sensing electromagnetic radiation of different wavelength. Absorption spectra are found within the strongest radiation from the sun and absorption usually triggers downstream signaling pathways. Until now, mainly 6 classes of representative photoreceptors are known: five water-soluble proteins, of these three classes of blue light-sensitive proteins including LOV (light-oxygen-voltage), BLUF (blue-light using FAD), and cryptochrome modules with flavin (vitamin B-related) nucleotides as chromophore; while two classes of yellow and red light-sensitive proteins consist of xanthopsin and phytochrome, respectively. Lastly, as uniquely integral membrane proteins, the class of rhodopsins can usually sense over a wide absorption spectrum, ranging from ultra-violet to green and even red light. Rhodopsins can be further divided into two types, i.e., microbial (type I) and animal (type II) rhodopsins. Rhodopsins consist of the protein opsin and the covalently bound chromophore retinal (vitamin A aldehyde). In this thesis, I focus on identification and characterization of novel type I opsins with guanylyl cyclase activity from green algae and a phosphodiesterase opsin from the protist Salpingoeca rosetta. Until 2014, all known type I and II rhodopsins showed a typical structure with seven transmembrane helices (7TM), an extracellular N-terminus and a cytosolic C-terminus. The proven function of the experimentally characterized type I rhodopsins was membrane transport of ions or the coupling to a transducer which enables phototaxis via a signaling chain. A completely new class of type I rhodopsins with enzymatic activity was identified in 2014. A light-activated guanylyl cyclase opsin was discovered in the fungus Blastocladiella emersonii which was named Cyclop (Cyclase opsin) by Gao et al. (2015), after heterologous expression and rigorous in-vitro characterization. BeCyclop is the first opsin for which an 8 transmembrane helices (8TM) structure was demonstrated by Gao et al. (2015). Earlier (2004), a novel class of enzymatic rhodopsins was predicted to exist in C. reinhardtii by expressed sequence tag (EST) and genome data, however, no functional data were provided up to now. The hypothetical rhodopsin included an N-terminal opsin domain, a fused two-component system with histidinekinase and response regulator domain, and a C-terminal guanylyl cyclase (GC) domain. This suggested that there could be a biochemical signaling cascade, integrating light-induction and ATP-dependent phosphate transfer, and as output the light-sensitive cGMP production. One of my projects focused on characterizing two such opsins from the green algae Chlamydomonas reinhardtii and Volvox carteri which we then named 2c-Cyclop (two-component Cyclase opsin), Cr2c-Cyclop and Vc2c-Cyclop, respectively. My results show that both 2c-Cyclops are light-inhibited GCs. Interestingly, Cr2c-Cyclop and Vc2c-Cyclop are very sensitive to light and ATP-dependent, whereby the action spectra of Cr2c-Cyclop and Vc2c-Cyclop peak at ~540 nm and ~560 nm, respectively. More importantly, guanylyl cyclase activity is dependent on continuous phosphate transfer between histidine kinase and response regulator. However, green light can dramatically block phosphoryl group transfer and inhibit cyclase activity. Accordingly, mutation of the retinal-binding lysine in the opsin domain resulted in GC activity and lacking light-inhibition. A novel rhodopsin phosphodiesterase from the protist Salpingoeca rosetta (SrRhoPDE) was discovered in 2017. However, the previous two studies of 2017 claimed a very weak or absent light-regulation. Here I give strong evidence for light-regulation by studying the activity of SrRhoPDE, expressed in Xenopus laevis oocytes, in-vitro at different cGMP concentrations. Surprisingly, hydrolysis of cGMP shows a ~100-fold higher turnover than that of cAMP. Light can enhance substrate affinity by decreasing the Km value for cGMP from 80 μM to 13 μM, but increases the maximum turnover only by ~30\%. In addition, two key single mutants, SrRhoPDE K296A or K296M, can abolish the light-activation effect by interrupting a covalent bond of Schiff base type to the chromophore retinal. I also demonstrate that SrRhoPDE shows cytosolic N- and C- termini, most likely via an 8-TM structure. In the future, SrRhoPDE can be a potentially useful optogenetic tool for light-regulation of cGMP concentration, possibly after further improvements by genetic engineering.}, language = {en} } @phdthesis{AdelAbdelrehimMohamedSoliman2019, author = {Adel Abdelrehim Mohamed Soliman, Hadya}, title = {Structural Equation Modeling of Factors Influencing EFL Reading comprehension: Comparative study between Egypt and Germany}, doi = {10.25972/OPUS-18695}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-186957}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {In most foreign language learning contexts, there are only rare chance for contact with native speakers of the target language. In such a situation, reading plays an important role in language acquisition as well as in gaining cultural information about the target language and its speakers. Previous research indicated that reading in foreign language is a complex process, which is influenced by various linguistic, cognitive and affective factors. The aim of the present study was to test two structural models of the relationship between reading comprehension in native language (L1), English language (L2) reading motivation, metacognitive awareness of L2 reading strategies, and reading comprehension of English as a foreign language among the two samples. Furthermore, the current study aimed to examine the differences between Egyptian and German students in their perceived usage of reading strategies during reading English texts, as well as to explore the pattern of their motivation toward reading English texts. For this purpose, 401 students were recruited from Germany (n=200) and Egypt (n=201) to participate in the current study. In order to have information about metacognitive awareness of reading strategies, a self-report questionnaire (SORS) developed by Moktari and Sheory (2002) was used. While the L2 reading motivation variable, was measured by a reading motivation survey (L2RMQ) which was based on reviewed reading motivation research. In addition, two reading tests were administrated one to measure reading comprehension for native language (German/Arabic) and the other to measure English reading comprehension. To analyze the collected data, descriptive statistics and independent t-tests were performed. In addition, further analysis using structural equation modeling was applied to test the strength of relationships between the variables under study. The results from the current research revealed that L1 reading comprehension, whether in a German or Arabic language, had the strongest relationship with L2 reading comprehension. However, the relationship between L2 intrinsic reading motivation was not proven to be significant in either the German or Egyptian models. On the other hand, the relationship between L2 extrinsic reading motivation, metacognitive awareness of reading strategies, and L2 reading comprehension was only proven significant in the German sample. The discussion of these results along with their pedagogical implications for education and practice will be illustrated in the following study.}, subject = {Leseverstehen}, language = {en} } @article{BruecknerDewhurstDellermannetal.2019, author = {Br{\"u}ckner, Tobias and Dewhurst, Rian D. and Dellermann, Theresa and M{\"u}ller, Marcel and Braunschweig, Holger}, title = {Mild synthesis of diboryldiborenes by diboration of B-B triple bonds}, series = {Chemical Science}, volume = {10}, journal = {Chemical Science}, doi = {10.1039/C9SC02544H}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-186306}, pages = {7375-7378}, year = {2019}, abstract = {A set of diboryldiborenes are prepared by the mild, catalyst-free, room-temperature diboration of the B-B triple bonds of doubly base-stabilized diborynes. Two of the product diboryldiborenes are found to be air- and water-stable in the solid state, an effect that is attributed to their high crystallinity and extreme insolubility in a wide range of solvents.}, language = {en} } @unpublished{LegarePranckeviciusBraunschweig2019, author = {L{\´e}gar{\´e}, Marc-Andr{\´e} and Pranckevicius, Conor and Braunschweig, Holger}, title = {Metallomimetic Chemistry of Boron}, series = {Chemical Reviews}, journal = {Chemical Reviews}, doi = {10.1021/acs.chemrev.8b00561}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-186317}, year = {2019}, abstract = {The study of main-group molecules that behave and react similarly to transition-metal (TM) complexes has attracted significant interest in recent decades. Most notably, the attractive idea of replacing the all-too-often rare and costly metals from catalysis has motivated efforts to develop main-group-element-mediated reactions. Main-group elements, however, lack the electronic flexibility of TM complexes that arises from combinations of empty and filled d orbitals and that seem ideally suited to bind and activate many substrates. In this review, we look at boron, an element that despite its nonmetal nature, low atomic weight, and relative redox staticity has achieved great milestones in terms of TM-like reactivity. We show how in interelement cooperative systems, diboron molecules, and hypovalent complexes the fifth element can acquire a truly metallomimetic character. As we discuss, this character is powerfully demonstrated by the reactivity of boron-based molecules with H2, CO, alkynes, alkenes and even with N2.}, language = {en} } @phdthesis{Knapp2019, author = {Knapp, Alexander Gerhard}, title = {Resonant Spin Flip Raman-Spectroscopy of Electrons and Manganese-Ions in the n-doped Diluted Magnetic Semiconductor (Zn,Mn)Se:Cl}, doi = {10.25972/OPUS-18609}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-186099}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Main focus of the present dissertation was to gain new insight about the interaction between magnetic ions and the conduction band of diluted magnetic semiconductors. This interaction in magnetic semiconductors with carrier concentrations near the metal-insulator transition (MIT) in an external magnetic field is barely researched. Hence, n-doped Zn1-xMnxSe:Cl samples were studied. Resonant Raman spectroscopy was employed at an external magnetic field between 1T and 7T and a temperature of 1.5K. The resulting magnetization of the material amplifies the splitting of states with opposite spins both in the valence and the conduction band. This is known as the "giant-Zeeman-effect". In this thesis, the resonance of the electron spin flip process, i.e. the enhancement of the signal depending on the excitation energy, was used as an indicator to determine the density of states of the charge carriers. The measured resonance profiles of each sample showed a structure, which consist of two partially overlapping Gaussian curves. The analysis of the Gaussian curves revealed that their respective maxima are separated independent of the magnetic field strenght by about 5 meV, which matches the binding energy of the donor bound exciton (D0, X). A widening of the full width at half maximum of the resonance profile was observed with increasing magnetic field. A detailed analysis of this behavior showed that the donor bound exciton spin flip resonance primarily accounts for the widening for all samples with doping concentrations below the metal insulator transition. A model was proposed for the interpretation of this observation. This is based on the fundamental assumptions of a spatially random distribution of the manganese ions on the group-II sublattice of the ZnSe crystal and the finite extension of the excitons. Thus, each exciton covers an individual quantity of manganese ions, which manifest as a local manganese concentration. This local manganese concentration is normally distributed for a set of excitons and hence, the evaluation of the distribution allows the determination of exciton radii Two trends were identified for the (D0, X) radii. The radius of the bound exciton decreases with increasing carrier concentration as well as with increasing manganese concentration. The determination of the (D0, X) radii by the use of resonant spin flip Raman spectroscopy and also the observation of the behavior of the (D0, X) radius depending on the carrier concentration, was achieved for the first time. For all samples with carrier concentrations below the metal-insulator transition, the obtained (X0) radii are up to a factor of 5.9 larger than the respective (D0, X) radii. This observation is explained by the unbound character of the (X0). For the first time, such an observation could be made by Raman spectroscopy.Beside the resonance studies, the shape of the Raman signal of the electron spin flip was analyzed. Thereby an obvious asymmetry of the signal, with a clear flank to lower Raman shifts, was observed. This asymmetry is most pronounced, when the spin flip process is excited near the (D0, X) resonance. To explain this observation, a theoretical model was introduced in this thesis. Based on the asymmetry of the resonantly excited spin flip signal, it was possible to estimate the (D0, X) radii, too. At external magnetic fields between 1.25T and 7T, the obtained radii lie between 2.38nm and 2.75nm. Additionally, the asymmetry of the electron spin flip signal was observed at different excitation energies. Here it is striking that the asymmetry vanishes with increasing excitation energy. At the highest excitation energy, where the electron spin flip was still detectable, the estimated radius of the exciton is 3.92nm. Beside the observations on the electron spin flip, the resonance behavior of the spin flip processes in the d-shell of the incorporated Mn ions was studied in this thesis. This was performed for the direct Mn spin flip process as well as for the sum process of the longitudinal optical phonon with the Mn spin flip. For the Stokes and anti-Stokes direct spin flip process and for the Stokes sum process, each the resonance curve is described by considering only one resonance mechanism. In contrast, resonance for the sum process in which an anti-Stokes Mn spin flip is involved, consists of two partially overlapping resonances due to different mechanisms. A detailed analysis of this resonance profile showed that for (Zn,Mn)Se at the chosen experimental parameters, an incoming and outgoing resonance can be achieved, separated by a few meV. Hereby, at a specific excitation energy range and a high excitation power, it was possible to achieve an inversion of the anti-Stokes to Stokes intensity, because only the anti-Stokes Mn spin flip process was enhanced resonantly.}, subject = {Raman-Spektroskopie}, language = {en} } @phdthesis{Scheiderer2019, author = {Scheiderer, Philipp}, title = {Spectroscopy of Prototypical Thin Film Mott Materials}, doi = {10.25972/OPUS-18635}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-186358}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The rich phase diagram of transition metal oxides essentially roots in the many body physics arising from strong Coulomb interactions within the underlying electron system. Understanding such electronic correlation effects remains challenging for modern solid state physics, therefore experimental data is required for further progress in the field. For this reason, spectroscopic investigations of prototypical correlated materials are the scope of this thesis. The experimental methods focus on photoelectron spectroscopy, and the test materials are the correlated metal SrVO\(_3\) and the Mott insulator LaTiO\(_3\), both of which are fabricated as high quality thin films. In SrVO\(_3\) thin films, a reduction of the film thickness induces a dimensional crossover from the metallic into the Mott insulating phase. In this thesis, an extrinsic chemical contribution from a surface over-oxidation is revealed that emerges additionally to the intrinsic change of the effective bandwidth usually identified to drive the transition. The two contributions are successfully disentangled by applying a capping layer that prevents the oxidation, allowing for a clean view on the dimensional crossover in fully stoichiometric samples. Indeed, these stoichiometric layers exhibit a higher critical thickness for the onset of the metallic phase than the bare and therefore over-oxidized thin films. For LaTiO\(_3\) thin films, the tendency to over-oxidize is even stronger. An uncontrolled oxygen diffusion from the substrate into the film is found to corrupt the electronic properties of LaTiO\(_3\) layers grown on SrTiO\(_3\). The Mott insulating phase is only detected in stoichiometric films fabricated on more suitable DyScO\(_3\) substrates. In turn, it is demonstrated that a \(controlled\) incorporation of excess oxygen ions by increasing the oxygen growth pressure is an effective way of \(p\) doping the material which is used to drive the band filling induced Mott transition. Gaining control of the oxygen stoichiometry in both materials allows for a systematic investigation of correlation effects in general and of the Mott transition in particular. The investigations are realized by various photoelectron spectroscopy techniques that provide a deep insight into the electronic structure. Resonant photoemission not only gives access to the titanium and vanadium related partial density of states of the valence band features, but also shows how the corresponding signal is enhanced by tuning the photon energy to the \(L\) absorption threshold. The enhanced intensity turns out to be very helpful for probing the Fermi surface topology and band dispersions by means of angular-resolved photoemission. The resulting momentum resolved electronic structure verifies central points of the theoretical description of the Mott transition, viz. the renormalization of the band width and a constant Luttinger volume in a correlated metal as the Mott phase is approached.}, subject = {{\"U}bergangsmetalloxide}, language = {en} } @phdthesis{Dirimanov2019, author = {Dirimanov, Stoyan Dinkov}, title = {Molecular Effects of Polyphenols in Experimental Type 2 Diabetes Mellitus and Metabolic Syndrome}, doi = {10.25972/OPUS-18570}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-185701}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The growing prevalence of type 2 diabetes mellitus (T2DM) demands novel therapeutic and adjuvant strategies. Polyphenols (PPs) are plant secondary metabolites. Epidemiological studies demonstrate an inverse relationship between their increased intake and the risk of development of T2DM and cardiovascular complications. However, the PPs' mechanism of action remains largely unknown. The present work aimed to expand knowledge regarding the effects of PPs on diabetes relevant molecular targets. Pycnogenol® (PYC) is a standardized pine bark extract which consists of oligomeric and monomeric PPs. Its anti-diabetic effects have been demonstrated in clinical trials. As a part of a human study involving 20 healthy volunteers, the extract's effects on dipeptidyl peptidase IV (DPP IV) were investigated. This protease terminates the insulin secretagogue action of incretins. Its inhibition is a promising strategy in T2DM treatment. This study uncovered that PYC-intake of 100 mg daily over 14 days statistically significantly reduced DPP IV serum concentrations by 8.2 \% (n= 38, p= 0.032). Contrary to expectations, this decrease was not paralleled by a reduction in the serum DPP IV enzymatic activity. To the best of our knowledge, the present study was the first investigating the effects of PPs on DPP IV serum concentrations and activities in humans. The finding that PYC is capable of reducing DPP IV serum concentrations might be important with regard to diabetes, where DPP IV levels are increased. Screenings for PPs' in vitro effects on DPP IV activity were performed employing a purified enzyme. The effects of tested PPs (among which PYC ingredients) at a physiologically relevant concentration of 5 µM were weak (< 10 \%) and too small compared to the reference compound sitagliptin, and thus not likely to be clinically relevant. This result is in discordance with some published data, but consistent with the outcome from the present human study. In addition, fluorescence interactions with the experimental setup were registered: under certain conditions urolithin B exhibited an autofluorescence which might mask eventual inhibitory activity. Quercetin quenched the fluorescence slightly which might contribute to false positive results. No statistically significant effects of selected constituents and metabolites of PYC on the total DPP IV protein expression were observed in 3T3-L1 adipocytes. Thus, the lower DPP IV in vivo concentrations after intake of PYC cannot be explained with down-regulation of the DPP IV expression in adipocytes. Akt kinase is responsible for the transmission of insulin signals and its dysregulation is related to insulin resistance and plays an important role in development of cardiovascular complications in T2DM. Thus, the modulation of the phosphorylation status of endothelial Akt-kinase, respectively its activity, might be a promising strategy in the management of these pathologies. This work aimed to uncover the effects of PPs from different structural subclasses on Akt-phosphorylation (pAkt) in endothelial cells (Ea.hy926). Short-term effects (5 - 30 min) were investigated at a concentration of 10 µM. In a pilot study two model PPs induced a moderate, but reproducible inhibition of pAkt Ser473 of 52.37 ± 21.01 \% (quercetin; p= 0.006, n= 3) and 37.79 ± 7.14 \% (resveratrol; p= 0.021, n= 4) compared to the negative control. A primary screening with Western blot analysis investigated the effects of eight compounds from different subclasses on pAkt Ser473 and Thr308 to reveal whether the observed inhibition PPs a group effect or specific to certain compounds. In addition to resveratrol and quercetin, statistically significant inhibitions of pAkt Ser473 were induced by luteolin (29.96 ± 11.06 \%, p< 0.01, n= 6) and apigenin (22.57 ± 10.30 \%, p< 0.01, n= 6). In contrast, genistein, 3,4,5-trimethoxystilbene, taxifolin and (+)-catechin caused no inhibition. A strong positive and statistically significant correlation between the mean inhibitory effects of the tested PPs on both Akt-residues Ser473 and Thr308 (r= 0.9478, p= 0.0003) was determined. A comprehensive secondary screening via ELISA involving 44 compounds from nine structural groups quantified the effects of PPs on pAkt Ser473 to uncover potential structure-activity features. The most potent inhibitors were luteolin (44.31 ± 17.95 \%), quercetin (35.71 ± 8.33 \%), urolithin A (35.28 ± 11.80 \%), apigenin (31.79 ± 6.16 \%), fisetin (28.09 ± 9.09 \%), and resveratrol (26.04 ± 5.58 \%). These effects were statistically significant (p< 0.01, n= 3 to 6). Further lead structure optimization might be based on the fact that the effects of luteolin and resveratrol also differed statistically significantly from each other (p= 0.008). To the best of our knowledge, the present study is the first to compare quantitatively the short term effects of PPs from different subclasses on pAkt in endothelial cells. Basic structure-activity relationships revealed that for flavones and flavonols the presence of a C2=C3 double bond (ring C) was essential for inhibitory activity and hydroxylation on the m- and p- positions in the ring B contributed to it. For stilbenoids, three free OH-groups appeared to be optimal. The comparison of the inhibitory potentials of ellagic acid and its microbial metabolites showed that urolithin A was statistically significantly more effective than its progenitor compound. Despite their structural similarities, the only active compound among all urolithins tested was urolithin A, hydroxylated at the C3 and C8 positions. This suggested a specific effect for urolithin A. Based on the common structural determinants and molecular geometry of the most active PPs a pharmacophore model regarding Akt-inhibition was proposed. In summary, the effects of a wide variety of PPs from diverse structural subclasses on the in vitro phosphorylation of endothelial Akt were quantitatively analyzed for the first time, the effects of previously undescribed compounds were determined and structure activity relationships were elucidated. The inhibitory potential of individual PPs might be beneficial in cases of sustained over-activation of Akt-kinase and its substrates such as S6 kinase as reported for certain T2DM-related pathological states, such as insulin resistance, endothelial dysfunction, excessive angiogenesis, vascular calcification, and insulin triggered DNA-damage. The results of the present work suggest potential molecular mechanisms of action of PP involving Akt-inhibition and DPP IV-down-regulation and thus contribute to the understanding of anti-diabetic effects of these compounds on the molecular level.}, subject = {Polyphenole}, language = {en} } @phdthesis{Akakpo2019, author = {Akakpo, Martin Gameli}, title = {The influence of learner characteristics on interactions to seek and share information in e-learning: A media psychology perspective}, doi = {10.25972/OPUS-18593}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-185934}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Research on the deployment and use of technology to assist learning has seen a significant rise over the last decades (Aparicio et al., 2017). The focus on course quality, technology, learning outcome and learner satisfaction in e-learning has led to insufficient attention by researchers to individual characteristics of learners (Cidral et al., 2017 ; Hsu et al., 2013). The current work aims to bridge this gap by investigating characteristics identified by previous works and backed by theory as influential individual differences in e-learning. These learner characteristics have been suggested as motivational factors (Edmunds et al., 2012) in decisions by learners to interact and exchange information (Luo et al., 2017). In this work e-learning is defined as interaction dependent information seeking and sharing enabled by technology. This is primarily approached from a media psychology perspective. The role of learner characteristics namely, beliefs about the source of knowledge (Schommer, 1990), learning styles (Felder \& Silverman, 1988), need for affect (Maio \& Esses, 2001), need for cognition (Cacioppo \& Petty, 1982) and power distance (Hofstede, 1980) on interactions to seek and share information in e-learning are investigated. These investigations were shaped by theory and empirical lessons as briefly mentioned in the next paragraphs. Theoretical support for investigations is derived from the technology acceptance model(TAM) by psychologist Davis (1989) and the hyper-personal model by communication scientist Walther (1996). The TAM was used to describe the influence of learner characteristics on decisions to use e-learning systems (Stantchev et al., 2014). The hyper-personal model described why computer-mediated communication thrives in e-learning (Kaye et al., 2016) and how learners interpret messages exchanged online (Hansen et al., 2015). This theoretical framework was followed by empirical reviews which justified the use of interaction and information seeking-sharing as key components of e-learning as well as the selection of learner characteristics. The reviews provided suggestions for the measurement of variables (K{\"u}hl et al., 2014) and the investigation design (Dascalau et al., 2015). Investigations were designed and implemented through surveys and quasi experiments which were used for three preliminary studies and two main studies. Samples were selected from Germany and Ghana with same variables tested in both countries. Hypotheses were tested with interaction and information seeking-sharing as dependent variables while beliefs about the source of knowledge, learning styles, need for affect, need for cognition and power distance were independent variables. Firstly, using analyses of variance, the influence of beliefs about the source of knowledge on interaction choices of learners was supported. Secondly, the role of need for cognition on interaction choices of learners was supported by results from a logistic regression. Thirdly, results from multiple linear regressions backed the influence of need for cognition and power distance on information seeking-sharing behaviour of learners. Fourthly, the relationship between need for affect and need for cognition was supported. The findings may have implications for media psychology research, theories used in this work, research on e-learning, measurement of learner characteristics and the design of e-learning platforms. The findings suggest that, the beliefs learners have about the source of knowledge, their need for cognition and their power distance can influence decisions to interact and seek or share information. The outlook from reviews and findings in this work predicts more research on learner characteristics and a corresponding intensity in the use of e-learning by individuals. It is suggested that future studies investigate the relationship between learner autonomy and power distance. Studies on inter-cultural similarities amongst e-learners in different populations are also suggested.}, subject = {e-learning}, language = {en} } @phdthesis{Schnells2019, author = {Schnells, Vera}, title = {Fractional Insulators and their Parent Hamiltonians}, doi = {10.25972/OPUS-18561}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-185616}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {In the past few years, two-dimensional quantum liquids with fractional excitations have been a topic of high interest due to their possible application in the emerging field of quantum computation and cryptography. This thesis is devoted to a deeper understanding of known and new fractional quantum Hall states and their stabilization in local models. We pursue two different paths, namely chiral spin liquids and fractionally quantized, topological phases. The chiral spin liquid is one of the few examples of spin liquids with fractional statistics. Despite its numerous promising properties, the microscopic models for this state proposed so far are all based on non-local interactions, making the experimental realization challenging. In the first part of this thesis, we present the first local parent Hamiltonians, for which the Abelian and non-Abelian chiral spin liquids are the exact and, modulo a topological degeneracy, unique ground states. We have developed a systematic approach to find an annihilation operator of the chiral spin liquid and construct from it a many-body interaction which establishes locality. For various system sizes and lattice geometries, we numerically find largely gapped eigenspectra and confirm to an accuracy of machine precision the uniqueness of the chiral spin liquid as ground state of the respective system. Our results provide an exact spin model in which fractional quantization can be studied. Topological insulators are one of the most actively studied topics in current condensed matter physics research. With the discovery of the topological insulator, one question emerged: Is there an interaction-driven set of fractionalized phases with time reversal symmetry? One intuitive approach to the theoretical construction of such a fractional topological insulator is to take the direct product of a fractional quantum Hall state and its time reversal conjugate. However, such states are well studied conceptually and do not lead to new physics, as the idea of taking a state and its mirror image together without any entanglement between the states has been well understood in the context of topological insulators. Therefore, the community has been looking for ways to implement some topological interlocking between different spin species. Yet, for all practical purposes so far, time reversal symmetry has appeared to limit the set of possible fractional states to those with no interlocking between the two spin species. In the second part of this thesis, we propose a new universality class of fractionally quantized, topologically ordered insulators, which we name "fractional insulator". Inspired by the fractional quantum Hall effect, spin liquids, and fractional Chern insulators, we develop a wave function approach to a new class of topological order in a two-dimensional crystal of spin-orbit coupled electrons. The idea is simply to allow the topological order to violate time reversal symmetry, while all locally observable quantities remain time reversal invariant. We refer to this situation as "topological time reversal symmetry breaking". Our state is based on the Halperin double layer states and can be viewed as a two-layer system of an ↑-spin and a ↓-spin sphere. The construction starts off with Laughlin states for the ↑-spin and ↓-spin electrons and an interflavor term, which creates correlations between the two layers. With a careful parameter choice, we obtain a state preserving time reversal symmetry locally, and label it the "311-state". For systems of up to six ↑-spin and six ↓-spin electrons, we manage to construct an approximate parent Hamiltonian with a physically realistic, local interaction.}, subject = {Spinfl{\"u}ssigkeit}, language = {en} } @phdthesis{Huestegge2019, author = {Huestegge, Sujata Maya}, title = {Cognitive mechanisms of voice processing}, doi = {10.25972/OPUS-18608}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-186086}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The present thesis addresses cognitive processing of voice information. Based on general theoretical concepts regarding mental processes it will differentiate between modular, abstract information processing approaches to cognition and interactive, embodied ideas of mental processing. These general concepts will then be transferred to the context of processing voice-related information in the context of parallel face-related processing streams. One central issue here is whether and to what extent cognitive voice processing can occur independently, that is, encapsulated from the simultaneous processing of visual person-related information (and vice versa). In Study 1 (Huestegge \& Raettig, in press), participants are presented with audio-visual stimuli displaying faces uttering digits. Audiovisual gender congruency was manipulated: There were male and female faces, each uttering digits with either a male or female voice (all stimuli were AV- synchronized). Participants were asked to categorize the gender of either the face or the voice by pressing one of two keys in each trial. A central result was that audio-visual gender congruency affected performance: Incongruent stimuli were categorized slower and more error-prone, suggesting a strong cross-modal interaction of the underlying visual and auditory processing routes. Additionally, the effect of incongruent visual information on auditory classification was stronger than the effect of incongruent auditory information on visual categorization, suggesting visual dominance over auditory processing in the context of gender classification. A gender congruency effect was also present under high cognitive load. Study 2 (Huestegge, Raettig, \& Huestegge, in press) utilized the same (gender-congruent and -incongruent) stimuli, but different tasks for the participants, namely categorizing the spoken digits (into odd/even or smaller/larger than 5). This should effectively direct attention away from gender information, which was no longer task-relevant. Nevertheless, congruency effects were still observed in this study. This suggests a relatively automatic processing of cross-modal gender information, which eventually affects basic speech-based information processing. Study 3 (Huestegge, subm.) focused on the ability of participants to match unfamiliar voices to (either static or dynamic) faces. One result was that participants were indeed able to match voices to faces. Moreover, there was no evidence for any performance increase when dynamic (vs. mere static) faces had to be matched to concurrent voices. The results support the idea that common person-related source information affects both vocal and facial features, and implicit corresponding knowledge appears to be used by participants to successfully complete face-voice matching. Taken together, the three studies (Huestegge, subm.; Huestegge \& Raettig, in press; Huestegge et al., in press) provided information to further develop current theories of voice processing (in the context of face processing). On a general level, the results of all three studies are not in line with an abstract, modular view of cognition, but rather lend further support to interactive, embodied accounts of mental processing.}, subject = {Stimme}, language = {en} } @phdthesis{Zapf2019, author = {Zapf, Michael}, title = {Oxidische Perovskite mit Hoher Massenzahl Z: D{\"u}nnfilmdeposition und Spektroskopische Untersuchungen}, doi = {10.25972/OPUS-18537}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-185370}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Perovskite oxides are a very versatile material class with a large variety of outstanding physical properties. A subgroup of these compounds particularly tempting to investigate are oxides involving high-\(Z\) elements, where spin-orbit coupling is expected to give rise to new intriguing phases and potential application-relevant functionalities. This thesis deals with the preparation and characterization of two representatives of high-\(Z\) oxide sample systems based on KTaO\(_3\) and BaBiO\(_3\). KTaO\(_3\) is a band insulator with an electronic valence configuration of Ta 5\(d\)\(^0\) . It is shown that by pulsed laser deposition of a disordered LaAlO\(_3\) film on the KTaO\(_3\)(001) surface, through the creation of oxygen vacancies, a Ta 5\(d\)\(^{0+\(\delta\)}\) state is obtained in the upmost crystal layers of the substrate. In consequence a quasi two dimensional electron system (q2DES) with large spin-orbit coupling emerges at the heterointerface. Measurements of the Hall effect establish sheet carrier densities in the range of 0.1-1.2 10\(^{14}\) cm\(^2\), which can be controlled by the applied oxygen background pressure during deposition and the LaAlO\(_3\) film thickness. When compared to the prototypical oxide q2DESs based on SrTiO\(_3\) crystals, the investigated system exhibits exceptionally large carrier mobilities of up to 30 cm\(^2\)/Vs (7000 cm\(^2\)/Vs) at room temperature (below 10 K). Through a depth profiling by photoemission spectra of the Ta 4\(f\) core level it is shown that the majority of the Ta 5\(d\)\(^0\) charge carriers, consisting of mobile and localized electrons, is situated within 4 nm from the interface at low temperatures. Furthermore, the momentum-resolved electronic structure of the q2DES \(buried\) underneath the LaAlO\(_3\) film is probed by means of hard X-ray angle-resolved photoelectron spectroscopy. It is inferred that, due to a strong confinement potential of the electrons, the band structure of the system is altered compared to \(n\)-doped bulk KTO. Despite the constraint of the electron movement along one direction, the Fermi surface exhibits a clear three dimensional momentum dependence, which is related to a depth extension of the conduction channels of at least 1 nm. The second material, BaBiO\(_3\), is a charge-ordered insulator, which has recently been predicted to emerge as a large-gap topological insulator upon \(n\)-doping. This study reports on the thin film growth of pristine BaBiO\(_3\) on Nb:SrTiO\(_3\)(001) substrates by means of pulsed laser deposition. The mechanism is identified that facilitates the development of epitaxial order in the heterostructure despite the presence of an extraordinary large lattice mismatch of 12 \%. At the heterointerface, a structurally modified layer of about 1.7 nm thickness is formed that gradually relieves the in-plane strain and serves as the foundation of a relaxed BBO film. The thereupon formed lattice orders laterally in registry with the substrate with the orientation BaBiO\(_3\)(001)||SrTiO\(_3\)(001) by so-called domain matching, where 8 to 9 BaBiO\(_3\) unit cells align with 9 to 10 unit cells of the substrate. Through the optimization of the deposition conditions in regard to the cation stoichiometry and the structural lattice quality, BaBiO\(_3\) thin films with bulk-like electronic properties are obtained, as is inferred from a comparison of valence band spectra with density functional theory calculations. Finally, a spectroscopic survey of BaBiO\(_3\) samples of various thicknesses resolves that a recently discovered film thickness-controlled phase transition in BaBiO\(_3\) thin films can be traced back to the structural and concurrent stoichiometric modifications occuring in the initially formed lattice on top of the SrTiO\(_3\) substrate rather than being purely driven by the smaller spatial extent of the BBO lattice.}, subject = {Perowskit}, language = {en} } @unpublished{EnglertStoyArrowsmithetal.2019, author = {Englert, Lukas and Stoy, Andreas and Arrowsmith, Merle and M{\"u}ssig, Jonas H. and Thaler, Melanie and Deißenberger, Andrea and H{\"a}fner, Alena and B{\"o}hnke, Julian and Hupp, Florian and Seufert, Jens and Mies, Jan and Damme, Alexander and Dellermann, Theresa and Hammond, Kai and Kupfer, Thomas and Radacki, Krzysztof and Thiess, Torsten and Braunschweig, Holger}, title = {Stable Lewis Base Adducts of Tetrahalodiboranes: Synthetic Methods and Structural Diversity}, series = {Chemistry - A European Journal}, journal = {Chemistry - A European Journal}, doi = {10.1002/chem.201901437}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-184888}, year = {2019}, abstract = {A series of 22 new bis(phosphine), bis(carbene) and bis(isonitrile) tetrahalodiborane adducts has been synthesized, either by direct adduct formation with highly sensitive B2X4 precursors (X = Cl, Br, I) or by ligand exchange at stable B2X4(SMe2)2 precursors (X = Cl, Br) with labile dimethylsulfide ligands. The isolated compounds have been fully characterized using NMR spectroscopic, (C,H,N)- elemental and, for 20 of these compounds, X-ray crystallographic analysis, revealing an unexpected variation in the bonding motifs. Besides the classical B2X4L2 diborane(6) adducts, some of the more sterically demanding carbene ligands induce a halide displacement leading to the first halide-bridged monocationic diboron species, [B2X3L2]A (A = BCl4, Br, I). Furthermore, low-temperature 1:1 reactions of B2Cl4 with sterically demanding N-heterocyclic carbenes led to the formation of kinetically unstable mono-adducts, one of which was structurally characterized. A comparison of the NMR and structural data of new and literature-known bis-adducts shows several trends pertaining to the nature of the halides and the stereoelectronic properties of the Lewis bases employed.}, language = {en} } @unpublished{BruecknerArrowsmithHessetal.2019, author = {Br{\"u}ckner, Tobias and Arrowsmith, Merle and Heß, Merlin and Hammond, Kai and M{\"u}ller, Marcel and Braunschweig, Holger}, title = {Synthesis of fused B,N-heterocycles by alkyne cleavage, NHC ring-expansion and C-H activation at a diboryne}, series = {Chemical Communications}, journal = {Chemical Communications}, doi = {10.1039/C9CC02657F}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-184899}, year = {2019}, abstract = {The addition of alkynes to a staturated N-heterocyclic carbene (NHC)-supported diboryne results in spontaneous cycloaddition, with complete B≡B and C≡C triple bond cleavage, NHC ring- expansion and activation of a variety of C-H bonds, leading to the formation of complex mixtures of fused B,N-heterocycles.}, language = {en} } @unpublished{ArrowsmithDoemlingSchmidtetal.2019, author = {Arrowsmith, Merle and D{\"o}mling, Michael and Schmidt, Uwe and Werner, Luis and Castro, Abril C. and Jim{\´e}nez-Halla, J. Oscar C. and M{\"u}ssig, Jonas and Prieschl, Dominic and Braunschweig, Holger}, title = {Spontaneous trans-Selective Transfer Hydrogenation of Apolar B=B Double Bonds}, series = {Angewandte Chemie, International Edition}, journal = {Angewandte Chemie, International Edition}, doi = {10.1002/anie.201902656}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-184874}, year = {2019}, abstract = {The transfer hydrogenation of NHC-supported diborenes with dimethylamine borane proceeds with high selectivity for the trans-1,2-dihydrodiboranes(6). DFT calculations suggest a stepwise proton-first-hydride-second reaction mechanism via an intermediate μ-hydrodiboronium dimethylaminoborate ion pair.}, language = {en} } @phdthesis{Aboagye2019, author = {Aboagye, Benjamin}, title = {Behavioral and physiologic consequences of inducible inactivation of the \(Tryptophan\) \(hydroxylase\) 2 gene in interaction with early-life adversity}, doi = {10.25972/OPUS-17358}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-173581}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Disruptions in brain serotonin (5-hydroxytryptamine, 5-HT) signaling pathways have been associated with etiology and pathogenesis of various neuropsychiatric disorders, but specific neural mechanisms of 5-HT function are yet to be fully elucidated. Tryptophan hydroxylase 2 (TPH2) is the rate-limiting enzyme for brain 5-HT synthesis. Therefore, in this study a tamoxifen (Tam)-inducible cre-mediated conditional gene (Tph2) knockout in adult mouse brain (Tph2icKO) has been established to decipher the specific role of brain 5-HT in the regulation of behavior in adulthood. Immunohistochemistry and high-performance liquid chromatography (HPLC) were used first to test the efficacy of Tam-inducible inactivation of Tph2 and consequential reduction of 5-HT in adult mouse brain. Tam treatment resulted in ≥90\% reduction in the number of 5-HT immuno-reactive cells in the anterior raphe nuclei. HPLC revealed a significant reduction in concentration of 5-HT and its metabolite 5-hydroxyindole acetic acid (5-HIAA) in selected brain regions of Tph2icKO, indicating the effectiveness of the protocol used. Second, standard behavioral tests were used to assess whether reduced brain 5-HT concentrations could alter anxiety-, fear- and depressive-like behavior in mice. No altered anxiety- and depressive-like behaviors were observed in Tph2icKO compared to control mice (Tph2CON) in all indices measured, but Tph2icKO mice exhibited intense and sustained freezing during context-dependent fear memory retrieval. Tph2icKO mice also exhibited locomotor hyperactivity in the aversive environments, such as the open field, and consumed more food and fluid than Tph2CON mice. Lastly, the combined effect of maternal separation (MS) stress and adult brain 5-HT depletion on behavior was assessed in male and female mice. Here, MS stress, 5-HT depletion and their interaction elicited anxiety-like behavior in a sex-dependent manner. MS reduced exploratory behavior in both male and female mice. Reduced 5-HT enhanced anxiety in female, but not in male mice. Furthermore, expression of genes related to the 5-HT system and emotionality (Tph2, Htr1a, Htr2a, Maoa and Avpr1a) was assessed by performing a quantitative real-time PCR. In Tph2icKO mice there was a reduction in expression of Tph2 in the raphe nuclei of both male and female mice. Interaction between MS stress and 5-HT deficiency was detected showing increased Htr2a and Maoa expression in raphe and hippocampus respectively of female mice. In male mice, MS stress and 5-HT depletion interaction effects reduced Avpr1a expression in raphe, while the expression of Htr1a, Htr2a and Maoa was differentially altered by 5-HT depletion and MS in various brain regions.}, subject = {Anxiety}, language = {en} } @phdthesis{Wermser2019, author = {Wermser, Charlotte}, title = {Morphology, regulation and interstrain interactions in a new macrocolony biofilm model of the human pathogen \(Staphylococcus\) \(aureus\)}, doi = {10.25972/OPUS-16593}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165931}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The role of multicellularity as the predominant microbial lifestyle has been affirmed by studies on the genetic regulation of biofilms and the conditions driving their formation. Biofilms are of prime importance for the pathology of chronic infections of the opportunistic human pathogen Staphylococcus aureus. The recent development of a macrocolony biofilm model in S. aureus opened new opportunities to study evolution and physiological specialization in biofilm communities in this organism. In the macrocolony biofilm model, bacteria form complex aggregates with a sophisticated spatial organization on the micro- and macroscale. The central positive and negative regulators of this organization in S. aureus are the alternative sigma factor σB and the quorum sensing system Agr, respectively. Nevertheless, nothing is known on additional factors controlling the macrocolony morphogenesis. In this work, the genome of S. aureus was screened for novel factors that are required for the development of the macrocolony architecture. A central role for basic metabolic pathways was demonstrated in this context as the macrocolony architecture was strongly altered by the disruption of nucleotide and carbohydrate synthesis. Environmental signals further modulate macrocolony morphogenesis as illustrated by the role of an oxygen-sensitive gene regulator, which is required for the formation of complex surface structures. A further application of the macrocolony biofilm model was demonstrated in the study of interstrain interactions. The integrity of macrocolony communities was macroscopically visibly disturbed by competitive interactions between clinical isolates of S. aureus. The results of this work contribute to the characterization of the macrocolony biofilm model and improve our understanding of developmental processes relevant in staphylococcal infections. The identification of anti-biofilm effects exercised through competitive interactions could lead to the design of novel antimicrobial strategies targeting multicellular bacterial communities.}, subject = {Staphylococcus aureus}, language = {en} } @phdthesis{Beck2019, author = {Beck, Sebastian}, title = {Using optogenetics to influence the circadian clock of \(Drosophila\) \(melanogaster\)}, doi = {10.25972/OPUS-18495}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-184952}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Almost all life forms on earth have adapted to the most impactful and most predictable recurring change in environmental condition, the cycle of day and night, caused by the axial rotation of the planet. As a result many animals have evolved intricate endogenous clocks, which adapt and synchronize the organisms' physiology, metabolism and behaviour to the daily change in environmental conditions. The scientific field researching these endogenous clocks is called chronobiology and has steadily grown in size, scope and relevance since the works of the earliest pioneers in the 1960s. The number one model organism for the research of circadian clocks is the fruit fly, Drosophila melanogaster, whose clock serves as the entry point to understanding the basic inner workings of such an intricately constructed endogenous timekeeping system. In this thesis it was attempted to combine the research on the circadian clock with the techniques of optogenetics, a fairly new scientific field, launched by the discovery of Channelrhodopsin 2 just over 15 years ago. Channelrhodopsin 2 is a light-gated ion channel found in the green alga Chlamydomonas reinhardtii. In optogenetics, researches use these light-gated ion channels like Channelrhodopsin 2 by heterologously expressing them in cells and tissues of other organisms, which can then be stimulated by the application of light. This is most useful when studying neurons, as these channels provide an almost non-invasive tool to depolarize the neuronal plasma membranes at will. The goal of this thesis was to develop an optogenetic tool, which would be able to influence and phase shift the circadian clock of Drosophila melanogaster upon illumination. A phase shift is the adaptive response of the circadian clock to an outside stimulus that signals a change in the environmental light cycle. An optogenetic tool, able to influence and phase shift the circadian clock predictably and reliably, would open up many new ways and methods of researching the neuronal network of the clock and which neurons communicate to what extent, ultimately synchronizing the network. The first optogenetic tool to be tested in the circadian clock of Drosophila melanogaster was ChR2-XXL, a channelrhodopsin variant with dramatically increased expression levels and photocurrents combined with a prolonged open state. The specific expression of ChR2-XXL and of later constructs was facilitated by deploying the three different clock-specific GAL4-driver lines, clk856-gal4, pdf-gal4 and mai179-gal4. Although ChR2-XXL was shown to be highly effective at depolarizing neurons, these stimulations proved to be unable to significantly phase shift the circadian clock of Drosophila. The second series of experiments was conducted with the conceptually novel optogenetic tools Olf-bPAC and SthK-bPAC, which respectively combine a cyclic nucleotide-gated ion channel (Olf and SthK) with the light-activated adenylyl-cyclase bPAC. These tools proved to be quite useful when expressed in the motor neurons of instar-3 larvae of Drosophila, paralyzing the larvae upon illumination, as well as affecting body length. This way, these new tools could be precisely characterized, spawning a successfully published research paper, centered around their electrophysiological characterization and their applicability in model organisms like Drosophila. In the circadian clock however, these tools caused substantial damage, producing severe arrhythmicity and anomalies in neuronal development. Using a temperature-sensitive GAL80-line to delay the expression until after the flies had eclosed, yielded no positive results either. The last series of experiments saw the use of another new series of optogenetic tools, modelled after the Olf-bPAC, with bPAC swapped out for CyclOp, a membrane-bound guanylyl-cyclase, coupled with less potent versions of the Olf. This final attempt however also ended up being unsuccessful. While these tools could efficiently depolarize neuronal membranes upon illumination, they were ultimately unable to stimulate the circadian clock in way that would cause it to phase shift. Taken together, these mostly negative results indicate that an optogenetic manipulation of the circadian clock of Drosophila melanogaster is an extremely challenging subject. As light already constitutes the most impactful environmental factor on the circadian clock, the combination of chronobiology with optogenetics demands the parameters of the conducted experiments to be tuned with an extremely high degree of precision, if one hopes to receive positive results from these types of experiments at all.}, subject = {Chronobiologie}, language = {en} } @phdthesis{Trabel2019, author = {Trabel, Mirko}, title = {Growth and Characterization of Epitaxial Manganese Silicide Thin Films}, doi = {10.25972/OPUS-18472}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-184720}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {This thesis describes the growth and characterization of epitaxial MnSi thin films on Si substrates. The interest in this material system stems from the rich magnetic phase diagram resulting from the noncentrosymmetric B20 crystal structure. Here neighboring spins prefer a tilted relative arrangement in contrast to ferro- and antiferromagnets, which leads to a helical ground state where crystal and spin helix chirality are linked [IEM+85]. This link makes the characterization and control of the crystal chirality the main goal of this thesis. After a brief description of the material properties and applied methods, the thesis itself is divided into four main parts. In the first part the advancement of the MBE growth process of MnSi on Si\((111)\) substrate as well as the fundamental structural characterization are described. Here the improvement of the substrate interface by an adjusted substrate preparation process is demonstrated, which is the basis for well ordered flat MnSi layers. On this foundation the influence of Mn/Si flux ratio and substrate temperature on the MnSi layer growth is investigated via XRD and clear boundaries to identify the optimal growth conditions are determined. The nonstoichiometric phases outside of this optimal growth window are identified as HMS and Mn\(_5\)Si\(_3\). Additionally, a regime at high substrate temperatures and low Mn flux is discovered, where MnSi islands are growing incorporated in a Si layer, which could be interesting for further investigations as a size confinement can change the magnetic phase diagram [DBS+18]. XRD measurements demonstrate the homogeneity of the grown MnSi layers over most of the 3 inch wafer diameter and a small \(\omega\)-FWHM of about 0.02° demonstrates the high quality of the layers. XRD and TEM measurements also show that relaxation of the layers happens via misfit dislocations at the interface to the substrate. The second part of the thesis is concerned with the crystal chirality. Here azimuthal \(\phi\)-scans of asymmetric XRD reflections reveal twin domains with a \(\pm\)30° rotation to the substrate. These twin domains seem to consist of left and right-handed MnSi, which are connected by a mirror operation at the \((\bar{1}10)\) plane. For some of the asymmetric XRD reflections this results in different intensities for the different twin domains, which reveals that one of the domains is rotated +30° and the other is rotated -30°. From XRD and TEM measurements an equal volume fraction of both domains is deduced. Different mechanisms to suppress these twin domains are investigated and successfully achieved with the growth on chiral Si surfaces, namely Si\((321)\) and Si\((531)\). Azimuthal \(\phi\)-scans of asymmetric XRD reflections demonstrate a suppression of up to 92\%. The successful twin suppression is an important step in the use of MnSi for the proposed spintronics applications with skyrmions as information carriers, as discussed in the introduction. Because of this achievement, the third part of the thesis on the magnetic properties of the MnSi thin films is not only concerned with the principal behavior, but also with the difference between twinned and twin suppressed layers. Magnetometry measurements are used to demonstrate, that the MnSi layers behave principally as expected from the literature. The analysis of saturation and residual magnetization hints to the twin suppression on Si\((321)\) and Si\((531)\) substrates and further investigations with more samples can complete this picture. For comparable layers on Si\((111)\), Si\((321)\) and Si\((531)\) the Curie-Weiss temperature is identical within 1 K and the critical field within 0.1 T. Temperature dependent magnetoresistivity measurements also demonstrate the expected \(T^2\) behavior not only on Si\((111)\) but also on Si\((321)\) substrates. This demonstrates the successful growth of MnSi on Si\((321)\) and Si\((531)\) substrates. The latter measurements also reveal a residual resistivity of less then half for MnSi on Si\((321)\) in comparison to Si\((111)\). This can be explained with the reduced number of domain boundaries demonstrating the successful suppression of one of the twin domains. The homogeneity of the residual resistivity as well as the charge carrier density over a wide area of the Si\((111)\) wafer is also demonstrated with these measurements as well as Hall effect measurements. The fourth part shows the AMR and PHE of MnSi depending on the angle between in plane current and magnetic field direction with respect to the crystal direction. This was proposed as a tool to identify skyrmions [YKT+15]. The influence of the higher C\(_{3\mathrm{v}}\) symmetry of the twinned system instead of the C\(_3\) symmetry of a B20 single crystal is demonstrated. The difference could serve as a useful additional tool to prove the twin suppression on the chiral substrates. But this is only possible for rotations with specific symmetry surfaces and not for the studied unsymmetrical Si\((321)\) surface. Measurements for MnSi layers on Si\((111)\) above the critical magnetic field demonstrate the attenuation of AMR and PHE parameters for increasing resistivity, as expected from literature [WC67]. Even if a direct comparison to the parameters on Si\((321)\) is not possible, the higher values of the parameters on Si\((321)\) can be explained considering the reduced charge carrier scattering from domain boundaries. Below the critical magnetic field, which would be the region where a skyrmion lattice could be expected, magnetic hysteresis complicates the analysis. Only one phase transition at the critical magnetic field can be clearly observed, which leaves the existence of a skyrmion lattice in thin epitaxial MnSi layers open. The best method to solve this question seems to be a more direct approach in the form of Lorentz-TEM, which was also successfully used to visualize the skyrmion lattice for thin plates of bulk MnSi [TYY+12]. For the detection of in plane skyrmions, lamellas would have to be prepared for a side view, which seems in principle possible. The demonstrated successful twin suppression for MnSi on Si\((321)\) and Si\((531)\) substrates may also be applied to other material systems. Suppressing the twinning in FeGe on Si\((111)\) would lead to a single chirality skyrmion lattice near room temperature [HC12]. This could bring the application of skyrmions as information carriers in spintronics within reach. Glossary: MBE Molecular Beam Epitaxy XRD X-Ray Diffraction HMS Higher Manganese Silicide FWHM Full Width Half Maximum TEM Tunneling Electron Microscopy AMR Anisotropic MagnetoResistance PHE Planar Hall Effect Bibliography: [IEM+85] M. Ishida, Y. Endoh, S. Mitsuda, Y. Ishikawa, and M. Tanaka. Crystal Chirality and Helicity of the Helical Spin Density Wave in MnSi. II. Polarized Neutron Diffraction. Journal of the Physical Society of Japan, 54(8):2975, 1985. [DBS+18] B. Das, B. Balasubramanian, R. Skomski, P. Mukherjee, S. R. Valloppilly, G. C. Hadjipanayis, and D. J. Sellmyer. Effect of size confinement on skyrmionic properties of MnSi nanomagnets. Nanoscale, 10(20):9504, 2018. [YKT+15] T. Yokouchi, N. Kanazawa, A. Tsukazaki, Y. Kozuka, A. Kikkawa, Y. Taguchi, M. Kawasaki, M. Ichikawa, F. Kagawa, and Y. Tokura. Formation of In-plane Skyrmions in Epitaxial MnSi Thin Films as Revealed by Planar Hall Effect. Journal of the Physical Society of Japan, 84(10):104708, 2015. [WC67] R. H. Walden and R. F. Cotellessa. Magnetoresistance of Nickel-Copper Single-Crystal Thin Films. Journal of Applied Physics, 38(3):1335, 1967. [TYY+12] A. Tonomura, X. Yu, K. Yanagisawa, T. Matsuda, Y. Onose, N. Kanazawa, H. S. Park, and Y. Tokura. Real-Space Observation of Skyrmion Lattice in Helimagnet MnSi Thin Samples. Nano Letters, 12(3):1673, 2012. [HC12] S. X. Huang and C. L. Chien. Extended Skyrmion Phase in Epitaxial FeGe(111) Thin Films. Physical Review Letters, 108(26):267201, 2012.}, subject = {Molekularstrahlepitaxie}, language = {en} } @phdthesis{Flechsenhar2019, author = {Flechsenhar, Aleya Felicia}, title = {The Ubiquity of Social Attention - a Detailed Investigation of the Underlying Mechanisms}, doi = {10.25972/OPUS-18452}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-184528}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {This dissertation highlights various aspects of basic social attention by choosing versatile approaches to disentangle the precise mechanisms underlying the preference to focus on other human beings. The progressive examination of different social processes contrasted with aspects of previously adopted principles of general attention. Recent research investigating eye movements during free exploration revealed a clear and robust social bias, especially for the faces of depicted human beings in a naturalistic scene. However, free viewing implies a combination of mechanisms, namely automatic attention (bottom-up), goal-driven allocation (top-down), or contextual cues and inquires consideration of overt (open exploration using the eyes) as well as covert orienting (peripheral attention without eye movement). Within the scope of this dissertation, all of these aspects have been disentangled in three studies to provide a thorough investigation of different influences on social attention mechanisms. In the first study (section 2.1), we implemented top-down manipulations targeting non-social features in a social scene to test competing resources. Interestingly, attention towards social aspects prevailed, even though this was detrimental to completing the requirements. Furthermore, the tendency of this bias was evident for overall fixation patterns, as well as fixations occurring directly after stimulus onset, suggesting sustained as well as early preferential processing of social features. Although the introduction of tasks generally changes gaze patterns, our results imply only subtle variance when stimuli are social. Concluding, this experiment indicates that attention towards social aspects remains preferential even in light of top-down demands. The second study (section 2.2) comprised of two separate experiments, one in which we investigated reflexive covert attention and another in which we tested reflexive as well as sustained overt attention for images in which a human being was unilaterally located on either the left or right half of the scene. The first experiment consisted of a modified dot-probe paradigm, in which peripheral probes were presented either congruently on the side of the social aspect, or incongruently on the non-social side. This was based on the assumption that social features would act similar to cues in traditional spatial cueing paradigms, thereby facilitating reaction times for probes presented on the social half as opposed to the non-social half. Indeed, results reflected such congruency effect. The second experiment investigated these reflexive mechanisms by monitoring eye movements and specifying the location of saccades and fixations for short as well as long presentation times. Again, we found the majority of initial saccades to be congruently directed to the social side of the stimulus. Furthermore, we replicated findings for sustained attention processes with highest fixation densities for the head region of the displayed human being. The third study (section 2.3), tackled the other mechanism proposed in the attention dichotomy, the bottom-up influence. Specifically, we reduced the available contextual information of a scene by using a gaze-contingent display, in which only the currently fixated regions would be visible to the viewer, while the remaining image would remain masked. Thereby, participants had to voluntarily change their gaze in order to explore the stimulus. First, results revealed a replication of a social bias in free-viewing displays. Second, the preference to select social features was also evident in gaze-contingent displays. Third, we find higher recurrent gaze patterns for social images compared to non-social ones for both viewing modalities. Taken together, these findings imply a top-down driven preference for social features largely independent of contextual information. Importantly, for all experiments, we took saliency predictions of different computational algorithms into consideration to ensure that the observed social bias was not a result of high physical saliency within these areas. For our second experiment, we even reduced the stimulus set to those images, which yielded lower mean and peak saliency for the side of the stimulus containing the social information, while considering algorithms based on low-level features, as well as pre-trained high-level features incorporated in deep learning algorithms. Our experiments offer new insights into single attentional mechanisms with regard to static social naturalistic scenes and enable a further understanding of basic social processing, contrasting from that of non-social attention. The replicability and consistency of our findings across experiments speaks for a robust effect, attributing social attention an exceptional role within the general attention construct, not only behaviorally, but potentially also on a neuronal level and further allowing implications for clinical populations with impaired social functioning.}, subject = {Aufmerksamkeit}, language = {en} } @phdthesis{Dietrich2019, author = {Dietrich, Georg}, title = {Ad Hoc Information Extraction in a Clinical Data Warehouse with Case Studies for Data Exploration and Consistency Checks}, doi = {10.25972/OPUS-18464}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-184642}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {The importance of Clinical Data Warehouses (CDW) has increased significantly in recent years as they support or enable many applications such as clinical trials, data mining, and decision making. CDWs integrate Electronic Health Records which still contain a large amount of text data, such as discharge letters or reports on diagnostic findings in addition to structured and coded data like ICD-codes of diagnoses. Existing CDWs hardly support features to gain information covered in texts. Information extraction methods offer a solution for this problem but they have a high and long development effort, which can only be carried out by computer scientists. Moreover, such systems only exist for a few medical domains. This paper presents a method empowering clinicians to extract information from texts on their own. Medical concepts can be extracted ad hoc from e.g. discharge letters, thus physicians can work promptly and autonomously. The proposed system achieves these improvements by efficient data storage, preprocessing, and with powerful query features. Negations in texts are recognized and automatically excluded, as well as the context of information is determined and undesired facts are filtered, such as historical events or references to other persons (family history). Context-sensitive queries ensure the semantic integrity of the concepts to be extracted. A new feature not available in other CDWs is to query numerical concepts in texts and even filter them (e.g. BMI > 25). The retrieved values can be extracted and exported for further analysis. This technique is implemented within the efficient architecture of the PaDaWaN CDW and evaluated with comprehensive and complex tests. The results outperform similar approaches reported in the literature. Ad hoc IE determines the results in a few (milli-) seconds and a user friendly GUI enables interactive working, allowing flexible adaptation of the extraction. In addition, the applicability of this system is demonstrated in three real-world applications at the W{\"u}rzburg University Hospital (UKW). Several drug trend studies are replicated: Findings of five studies on high blood pressure, atrial fibrillation and chronic renal failure can be partially or completely confirmed in the UKW. Another case study evaluates the prevalence of heart failure in inpatient hospitals using an algorithm that extracts information with ad hoc IE from discharge letters and echocardiogram report (e.g. LVEF < 45 ) and other sources of the hospital information system. This study reveals that the use of ICD codes leads to a significant underestimation (31\%) of the true prevalence of heart failure. The third case study evaluates the consistency of diagnoses by comparing structured ICD-10-coded diagnoses with the diagnoses described in the diagnostic section of the discharge letter. These diagnoses are extracted from texts with ad hoc IE, using synonyms generated with a novel method. The developed approach can extract diagnoses from the discharge letter with a high accuracy and furthermore it can prove the degree of consistency between the coded and reported diagnoses.}, subject = {Information Extraction}, language = {en} } @phdthesis{Potabattula2019, author = {Potabattula, Ramya Sri Krishna}, title = {Male aging and obesity effects on sperm methylome and consequences for the next generation}, doi = {10.25972/OPUS-16548}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165481}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2019}, abstract = {Besides a growing tendency for delayed parenthood, sedentary lifestyle coupled with overnutrition has dramatically increased worldwide over the last few decades. Epigenetic mechanisms can help us understand the epidemics and heritability of complex traits like obesity to a significant extent. Majority of the research till now has focused on determining the impact of maternal factors on health and disease risk in the offspring(s). This doctoral thesis is focused on deciphering the potential effects of male aging and obesity on sperm methylome, and consequences/transmission via germline to the next generation. In humans, this was assessed in a unique cohort of ~300 sperm samples, collected after in vitro fertilization/intracytoplasmic sperm injection, as well as in conceived fetal cord blood samples of the children. Furthermore, aging effect on sperm samples derived from a bovine cohort was analyzed. The study identified that human male aging significantly increased the DNA methylation levels of the promoter, the upstream core element, the 18S, and the 28S regions of ribosomal DNA (rDNA) in sperm. Prediction models were developed to anticipate an individual's age based on the methylation status of rDNA regions in his sperm. Hypermethylation of alpha satellite and LINE1 repeats in human sperm was also observed with aging. Epimutations, which are aberrantly methylated CpG sites, were significantly higher in sperm of older males compared to the younger ones. These effects on the male germline had a negative impact on embryo quality of the next generation. Consistent with these results, DNA methylation of rDNA regions, bovine alpha satellite, and testis satellite repeats displayed a significant positive correlation with aging sperm samples within the same individual and across different age-grouped bulls. A positive association between human male obesity/body mass index (BMI) and DNA methylation of the imprinted MEG3 gene and the obesity-related HIF3A gene was detected in sperm. These BMI-induced sperm DNA methylation signatures were transmitted to next generation fetal cord blood (FCB) samples in a gender-specific manner. Males, but not female offsprings exhibited a significant positive correlation between father's BMI and FCB DNA methylation in the two above-mentioned amplicons. Additionally, hypomethylation of IGF2 with increased paternal BMI was observed in female FCB samples. Parental allele-specific in-depth methylation analysis of imprinted genes using next generation sequencing technology also revealed significant correlations between paternal factors like age and BMI, and the corresponding father's allele DNA methylation in FCB samples. Deep bisulphite sequencing of imprinted genes in diploid somatic cord blood cells of offspring detected that the levels of DNA methylation signatures largely depended on the underlying genetic variant, i.e. sequence haplotypes. Allele-specific epimutations were observed in PEG1, PEG5, MEG3, H19, and IGF2 amplicons. For the former three genes, the non-imprinted unmethylated allele displayed more epimutations than the imprinted methylated allele. On the other hand, for the latter two genes, the imprinted allele exhibited higher epimutation rate than that of the non-imprinted allele. In summary, the present study proved that male aging and obesity impacts the DNA methylome of repetitive elements and imprinted genes respectively in sperm, and also has considerable consequences on the next generation. Nevertheless, longitudinal follow-up studies are highly encouraged to elucidate if these effects can influence the risk of developing abnormal phenotype in the offspring during adulthood.}, language = {en} } @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} }