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ResearcherID
- M-1240-2017 (1)
In the 1960s, when most African nations gained their independence after the age of colonialism, several theories and strategies emerged with the goal of "developing" these apparently "underdeveloped" territories. One of the most influential approaches for this task was represented in Julius K. Nyerere´s idea of Ujamaa, the Tanzanian version of African socialism.
Even before the Arusha Declaration established Ujamaa as a national development strategy in 1967, several groups of politicized young farmers took to the empty countryside of Tanzania to implement their own version of cooperative development. From one of these attempts emerged the Ruvuma Development Association (RDA), which organized up to 18 villages in southwestern Tanzania. The RDA became the inspiration for Nyerere´s concretization of Ujamaa and its implementation on national level. Yet, the central state could not replicate the success of the peasants, which was based on voluntariness and intrinsic motivation.
In 2015, this exploratory study has revisited the Region of Ruvuma. Through a case study approach, relying mostly on qualitative methods, new insights into the local history of Ujamaa and its perception have been gathered. In particular, narrative interviews with contemporary witnesses and group interviews with the present-day farmers’ groups have been conducted. Furthermore, NGOs active within the region, as well as regional and local government institutions were among the key stakeholders identified to concretize the local narrative of Ujamaa development. All interviews were analyzed according to the principles of qualitative content analysis. Additionally, individual villager questionnaires were used to achieve a more holistic picture of the local perception of development, challenges and the Ujamaa era.
None of the original Ujamaa groups of the times of the RDA was still operational at the time of research and no case of village-wide organization of collective agriculture could be observed. Nevertheless, in all of the three case study villages, several farmers’ groups (vikundi) were active in organizing development activities for their members. Furthermore, the perception of the Ujamaa era was generally positive throughout all of the case study sites. Yet, there have been significant differences in this perception, based on the village, age, gender and field size of the recipients. Overall, the period of Ujamaa was seen as an inspiration for present-day group activities, and the idea of such activities as a remedy for the developmental challenges of these villages was common among all stakeholders.
This thesis concludes that the positive perception of group activities as a vehicle for village development and the perception of Ujamaa history as a positive asset for the inception and organization of farmers’ groups would be highly beneficial to further attempts to support such development activities. However, the limitations in market access and capital availability for these highly-motivated group members have to be addressed by public and private development institutions. Otherwise, "the smell of Ujamaa" will be of little use for the progress of these villages.
Chemokine (C-X-C motif) receptor 4 (CXCR4) is a key factor for tumor growth and metastasis in several types of human cancer including multiple myeloma (MM). Proof-of-concept of CXCR4-directed radionuclide therapy in MM has recently been reported. This study assessed the diagnostic performance of the CXCR4-directed radiotracer [\(^{68}\)Ga]Pentixafor in MM and a potential role for stratifying patients to CXCR4-directed therapies.
Thirty-five patients with MM underwent [\(^{68}\)Ga]Pentixafor-PET/CT for evaluation of eligibility for endoradiotherapy. In 19/35 cases, [\(^{18}\)F]FDG-PET/CT for correlation was available. Scans were compared on a patient and on a lesion basis. Tracer uptake was correlated with standard clinical parameters of disease activity.
[\(^{68}\)Ga]Pentixafor-PET detected CXCR4-positive disease in 23/35 subjects (66%). CXCR4-positivity at PET was independent from myeloma subtypes, cytogenetics or any serological parameters and turned out as a negative prognostic factor. In the 19 patients in whom a comparison to [\(^{18}\)F]FDG was available, [\(^{68}\)Ga]Pentixafor-PET detected more lesions in 4/19 (21%) subjects, [\(^{18}\)F]FDG proved superior in 7/19 (37%). In the remaining 8/19 (42%) patients, both tracers detected an equal number of lesions. [\(^{18}\)F]FDG-PET positivity correlated with [\(^{68}\)Ga]Pentixafor-PET positivity (p=0.018).
[\(^{68}\)Ga]Pentixafor-PET provides further evidence that CXCR4 expression frequently occurs in advanced multiple myeloma, representing a negative prognostic factor and a potential target for myeloma specific treatment. However, selecting patients for CXCR4 directed therapies and prognostic stratification seem to be more relevant clinical applications for this novel imaging modality, rather than diagnostic imaging of myeloma.
\(^{11}\)C-methionine-PET in multiple myeloma: a combined study from two different institutions
(2017)
\(^{11}\)C-methionine (MET) has recently emerged as an accurate marker of tumor burden and disease activity in patients with multiple myeloma (MM). This dual-center study aimed at further corroboration of the superiority of MET as positron emission tomography (PET) tracer for staging and re-staging MM, as compared to \(^{18}\)F-2`-deoxy-2`-fluoro-D-glucose (FDG).
78 patients with a history of solitary plasmacytoma (n=4), smoldering MM (SMM, n=5), and symptomatic MM (n=69) underwent both MET- and FDG-PET/computed tomography (CT) at the University Centers of Würzburg, Germany and Navarra, Spain. Scans were compared on a patient and on a lesion basis. Inter-reader agreement was also evaluated. In 2 patients, tumor biopsies for verification of discordant imaging results were available.
MET-PET detected focal lesions (FL) in 59/78 subjects (75.6%), whereas FDG-PET/CT showed lesions in only 47 patients (60.3%; p<0.01), accordingly disease activity would have been missed in 12 patients. Directed biopsies of discordant results confirmed MET-PET/CT results in both cases.
MET depicted more FL in 44 patients (56.4%; p<0.01), whereas in two patients (2/78), FDG proved superior. In the remainder (41.0%, 32/78), both tracers yielded comparable results. Inter-reader agreement for MET was higher than for FDG (κ = 0.82 vs κ = 0.72).
This study demonstrates higher sensitivity of MET in comparison to standard FDG to detect intra- and extramedullary MM including histologic evidence of FDG-negative, viable disease exclusively detectable by MET-PET/CT. MET holds the potential to replace FDG as functional imaging standard for staging and re-staging of MM.
Context: Patients with primary adrenal insufficiency (PAI) or congenital adrenal hyperplasia (CAH) are at a high risk of adrenal crisis (AC). Glucocorticoid sensitivity is at least partially genetically determined by polymorphisms of the glucocorticoid receptor (GR).
Objectives: To determine if a number of intercurrent illnesses and AC are associated with the GR gene polymorphism \(Bcl\)I in patients with PAI and CAH.
Design and patients: This prospective, longitudinal study over 37.7 ± 10.1 months included 47 PAI and 25 CAH patients. During the study period, intercurrent illness episodes and AC were documented.
Results: The study period covered 223 patient years in which 21 AC occurred (9.4 AC/100 pat years). There were no significant differences between \(Bcl\)I polymorphisms (CC (n=29), CG (n=34) and GG (n=9)) regarding BMI, hydrocortisone equivalent daily dose and blood pressure. We did not find a difference in the number of intercurrent illnesses/patient year among \(Bcl\)I polymorphisms (CC (1.5±1.4/pat year), CG (1.2±1.2/pat year) and GG (1.6±2.2/pat year)). The occurrence of AC was not significantly different among the homozygous (GG) genotype (32.5 AC/100 pat years), the CC genotype (6.7 AC/100 pat years) and the CG genotype (4.9 AC/100 pat years). Concomitant hypothyroidism was the highest in the GG genotype group (5/9), compared to others (CC (11/29) and CG (11/34)).
Conclusions: Although sample sizes were relatively small and results should be interpreted with caution, this study suggests that the GR gene polymorphism \(Bcl\)I may not be associated with the frequencies of intercurrent illnesses and AC.
Surgical implantation of a biomaterial triggers foreign-body-induced fibrous encapsulation. Two major mechanisms of this complex physiological process are (I) chemotaxis of fibroblasts from surrounding tissue to the implant region, followed by (II) tissue remodeling. As an alternative to animal studies, we here propose a process-aligned \({in}\) \({vitro}\) test platform to investigate the material dependency of fibroblast chemotaxis and tissue remodeling mediated by material-resident macrophages.
Embedded in a biomimetic three-dimensional collagen hydrogel, chemotaxis of fibroblasts in the direction of macrophage-material-conditioned cell culture supernatant was analyzed by live cell imaging. A combination of statistical analysis with a complementary parameterized random walk model allowed quantitative and qualitative characterization of the cellular walk process. We thereby identified an increasing macrophage-mediated chemotactic potential ranking of biomaterials from glass over polytetrafluorethylene to titanium. To address long-term effects of biomaterial-resident macrophages on fibroblasts in a three-dimensional microenvironment, we further studied tissue remodeling by applying macrophage-material-conditioned medium on fibrous \({in}\) \({vitro}\) tissue models. A high correlation of the \({in}\) \({vitro}\) tissue model to state of the art \({in}\) \({vivo}\) study data was found. Titanium exhibited a significantly lower tissue remodeling capacity compared to polytetrafluorethylene. With this approach, we identified a material dependency of both chemotaxis and tissue remodeling processes, strengthening knowledge on their specific contribution to the foreign body reaction.
Blood platelets are produced by large bone marrow (BM) precursor cells, megakaryocytes (MKs), which extend cytoplasmic protrusions (proplatelets) into BM sinusoids. The molecular cues that control MK polarization towards sinusoids and limit transendothelial crossing to proplatelets remain unknown. Here, we show that the small GTPases Cdc42 and RhoA act as a regulatory circuit downstream of the MK-specific mechanoreceptor GPIb to coordinate polarized transendothelial platelet biogenesis. Functional deficiency of either GPIb or Cdc42 impairs transendothelial proplatelet formation. In the absence of RhoA, increased Cdc42 activity and MK hyperpolarization triggers GPIb-dependent transmigration of entire MKs into BM sinusoids. These findings position Cdc42 (go-signal) and RhoA (stop-signal) at the centre of a molecular checkpoint downstream of GPIb that controls transendothelial platelet biogenesis. Our results may open new avenues for the treatment of platelet production disorders and help to explain the thrombocytopenia in patients with Bernard–Soulier syndrome, a bleeding disorder caused by defects in GPIb-IX-V.
Despite growing effort to advance materials towards a low fibrotic progression, all implants elicit adverse tissue responses. Pre-clinical biomaterial assessment relies on animals testing, which can be complemented by in vitro tests to address the Russell and Burch’s 3R aspect of reducing animal burden. However, a poor correlation between in vitro and in vivo biomaterial assessments confirms a need for suitable in vitro biomaterial tests. The aim of the study was to identify a test setting, which is predictive and might be time- and cost-efficient. We demonstrated how sensitive in vitro biomaterial assessment based on human primary macrophages depends on test conditions. Moreover, possible clinical scenarios such as lipopolysaccharide contamination, contact to autologous blood plasma, and presence of IL-4 in an immune niche influence the outcome of a biomaterial ranking. Nevertheless, by using glass, titanium, polytetrafluorethylene, silicone, and polyethylene representing a specific material-induced fibrotic response and by comparison to literature data, we were able to identify a test condition that provides a high correlation to state-of-the-art in vivo studies. Most important, biomaterial ranking obtained under native plasma test conditions showed a high predictive accuracy compared to in vivo assessments, strengthening a biomimetic three-dimensional in vitro test platform.
The human ubiquitin ligase HUWE1 has key roles in tumorigenesis, yet it is unkown how its activity is regulated. We present the crystal structure of a C-terminal part of HUWE1, including the catalytic domain, and reveal an asymmetric auto-inhibited dimer. We show that HUWE1 dimerizes in solution and self-associates in cells, and that both occurs through the crystallographic dimer interface. We demonstrate that HUWE1 is inhibited in cells and that it can be activated by disruption of the dimer interface. We identify a conserved segment in HUWE1 that counteracts dimer formation by associating with the dimerization region intramolecularly. Our studies reveal, intriguingly, that the tumor suppressor p14ARF binds to this segment and may thus shift the conformational equilibrium of HUWE1 toward the inactive state. We propose a model, in which the activity of HUWE1 underlies conformational control in response to physiological cues—a mechanism that may be exploited for cancer therapy.
Timing seasonal events, like reproduction or diapause, is crucial for the survival of many species. Global change causes phenologies worldwide to shift, which requires a mechanistic explanation of seasonal time measurement. Day length (photoperiod) is a reliable indicator of winter arrival, but it remains unclear how exactly species measure day length. A reference for time of day could be provided by a circadian clock, by an hourglass clock, or, as some newer models suggest, by a damped circadian clock. However, damping of clock outputs has so far been rarely observed. To study putative clock outputs of Acyrthosiphon pisum aphids, we raised individual nymphs on coloured artificial diet, and measured rhythms in metabolic activity in light-dark illumination cycles of 16:08 hours (LD) and constant conditions (DD). In addition, we kept individuals in a novel monitoring setup and measured locomotor activity. We found that A. pisum is day-active in LD, potentially with a bimodal distribution. In constant darkness rhythmicity of locomotor behaviour persisted in some individuals, but patterns were mostly complex with several predominant periods. Metabolic activity, on the other hand, damped quickly. A damped circadian clock, potentially driven by multiple oscillator populations, is the most likely explanation of our results.
In Germany, as in many Western societies, demographic change will lead to a higher number of senior visitors to natural recreational areas and national parks. Given the high physiological requirements of many outdoor recreation activities, especially in mountain areas, it seems likely that demographic change will affect the spatial behaviour of national park visitors, which may pose a challenge to the management of these areas. With the help of GPS tracking and a standardized questionnaire (n=481), this study empirically investigates the spatial behaviour of demographic age brackets in Berchtesgaden National Park (NP) and the potential effects of demographic change on the use of the area. Cluster analysis revealed four activity types in the study area. More than half of the groups with visitors aged 60 and older belong to the activity type of Walker.
We analyze the concomitant spontaneous breaking of translation and conformal symmetries by introducing in a CFT a complex scalar operator that acquires a spatially dependent expectation value. The model, inspired by the holographic Q-lattice, provides a privileged setup to study the emergence of phonons from a spontaneous translational symmetry breaking in a conformal field theory and offers valuable hints for the treatment of phonons in QFT at large. We first analyze the Ward identity structure by means of standard QFT techniques, considering both spontaneous and explicit symmetry breaking. Next, by implementing holographic renormalization, we show that the same set of Ward identities holds in the holographic Q-lattice. Eventually, relying on the holographic and QFT results, we study the correlators realizing the symmetry breaking pattern and how they encode information about the low-energy spectrum.
A measurement of the calorimeter response to isolated charged hadrons in the ATLAS detector at the LHC is presented. This measurement is performed with 3.2 nb\(^{−1}\) of proton–proton collision data at \(\sqrt{s}\) = 7 TeV from 2010 and 0.1 nb\(^{−1}\) of data at \(\sqrt{s}\) = 8 TeV from 2012. A number of aspects of the calorimeter response to isolated hadrons are explored. After accounting for energy deposited by neutral particles, there is a 5% discrepancy in the modelling, using various sets of GEANT4 hadronic physics models, of the calorimeter response to isolated charged hadrons in the central calorimeter region. The description of the response to anti-protons at low momenta is found to be improved with respect to previous analyses. The electromagnetic and hadronic calorimeters are also examined separately, and the detector simulation is found to describe the response in the hadronic calorimeter well. The jet energy scale uncertainty and correlations in scale between jets of different momenta and pseudorapidity are derived based on these studies. The uncertainty is 2–5% for jets with transverse momenta above 2 TeV, where this method provides the jet energy scale uncertainty for ATLAS.
Current brain-computer interface (BCIs) software is often tailored to the needs of scientists and technicians and therefore complex to allow for versatile use. To facilitate home use of BCIs a multifunctional P300 BCI with a graphical user interface intended for non-expert set-up and control was designed and implemented. The system includes applications for spelling, web access, entertainment, artistic expression and environmental control. In addition to new software, it also includes new hardware for the recording of electroencephalogram (EEG) signals. The EEG system consists of a small and wireless amplifier attached to a cap that can be equipped with gel-based or dry contact electrodes. The system was systematically evaluated with a healthy sample, and targeted end users of BCI technology, i.e., people with a varying degree of motor impairment tested the BCI in a series of individual case studies. Usability was assessed in terms of effectiveness, efficiency and satisfaction. Feedback of users was gathered with structured questionnaires. Two groups of healthy participants completed an experimental protocol with the gel-based and the dry contact electrodes (N = 10 each). The results demonstrated that all healthy participants gained control over the system and achieved satisfactory to high accuracies with both gel-based and dry electrodes (average error rates of 6 and 13%). Average satisfaction ratings were high, but certain aspects of the system such as the wearing comfort of the dry electrodes and design of the cap, and speed (in both groups) were criticized by some participants. Six potential end users tested the system during supervised sessions. The achieved accuracies varied greatly from no control to high control with accuracies comparable to that of healthy volunteers. Satisfaction ratings of the two end-users that gained control of the system were lower as compared to healthy participants. The advantages and disadvantages of the BCI and its applications are discussed and suggestions are presented for improvements to pave the way for user friendly BCIs intended to be used as assistive technology by persons with severe paralysis.
Despite medical achievements, the number of patients with end-stage kidney disease keeps steadily raising, thereby entailing a high number of surgical and interventional procedures to establish and maintain arteriovenous vascular access for hemodialysis. Due to vascular disease, aneurysms or infection, the preferred access—an autogenous arteriovenous fistula—is not always available and appropriate. Moreover, when replacing small diameter blood vessels, synthetic vascular grafts possess well-known disadvantages. A continuous multilayered gradient electrospinning was used to produce vascular grafts made of collagen type I nanofibers on luminal and adventitial graft side, and poly-ɛ-caprolactone as medial layer. Therefore, a custom-made electrospinner with robust environmental control was developed. The morphology of electrospun grafts was characterized by scanning electron microscopy and measurement of mechanical properties. Human microvascular endothelial cells were cultured in the graft under static culture conditions and compared to cultures obtained from dynamic continuous flow bioreactors. Immunofluorescent analysis showed that endothelial cells form a continuous luminal layer and functional characteristics were confirmed by uptake of acetylated low-density-lipoprotein. Incorporation of vancomycin and gentamicin to the medial graft layer allowed antimicrobial inhibition without exhibiting an adverse impact on cell viability. Most striking a physiological hemocompatibility was achieved for the multilayered grafts.
Intercellular adhesion plays a major role in tissue development and homeostasis. Yet, technologies to measure mature cell-cell contacts are not available. We introduce a methodology based on fluidic probe force microscopy to assess cell-cell adhesion forces after formation of mature intercellular contacts in cell monolayers. With this method we quantify that L929 fibroblasts exhibit negligible cell-cell adhesion in monolayers whereas human endothelial cells from the umbilical artery (HUAECs) exert strong intercellular adhesion forces per cell. We use a new in vitro model based on the overexpression of Muscle Segment Homeobox 1 (MSX1) to induce Endothelial-to-Mesenchymal Transition (EndMT), a process involved in cardiovascular development and disease. We reveal how intercellular adhesion forces in monolayer decrease significantly at an early stage of EndMT and we show that cells undergo stiffening and flattening at this stage. This new biomechanical insight complements and expands the established standard biomolecular analyses. Our study thus introduces a novel tool for the assessment of mature intercellular adhesion forces in a physiological setting that will be of relevance to biological processes in developmental biology, tissue regeneration and diseases like cancer and fibrosis.
Background: Beyond survival of nowadays >80%, modern childhood cancer treatment strives to preserve long-term health and quality of life. However, the majority of today’s survivors suffer from short- and long-term adverse effects such as cardiovascular and pulmonary diseases, obesity, osteoporosis, fatigue, depression, and reduced physical fitness and quality of life. Regular exercise can play a major role to mitigate or prevent such late-effects. Despite this, there are no data on the effects of regular exercise in childhood cancer survivors from randomized controlled trials (RCTs). \(Primary\) \(outcome\) of the current RCT is therefore the effect of a 12-months exercise program on a composite cardiovascular disease risk score in childhood cancer survivors. \(Secondary\) \(outcomes\) are single cardiovascular disease risk factors, glycaemic control, bone health, body composition, physical fitness, physical activity, quality of life, mental health, fatigue and adverse events (safety).
Methods: A total of 150 childhood cancer survivors aged ≥16 years and diagnosed ≥5 years prior to the study are recruited from Swiss paediatric oncology clinics. Following the baseline assessments patients are randomized 1:1 into an intervention and control group. Thereafter, they are seen at month 3, 6 and 12 for follow-up assessments. The intervention group is asked to add ≥2.5 h of intense physical activity/week, including 30 min of strength building and 2 h of aerobic exercises. In addition, they are told to reduce screen time by 25%. Regular consulting by physiotherapists, individual web-based activity diaries, and pedometer devices are used as motivational tools for the intervention group. The control group is asked to keep their physical activity levels constant.
Discussion: The results of this study will show whether a partially supervised exercise intervention can improve cardiovascular disease risk factors, bone health, body composition, physical activity and fitness, fatigue, mental health and quality of life in childhood cancer survivors. If the program will be effective, all relevant information of the SURfit physical activity intervention will be made available to interested clinics that treat and follow-up childhood cancer patients to promote exercise in their patients.
Background:
The foamy viral genome encodes four central purine-rich elements localized in the integrase-coding region of pol. Previously, we have shown that the first two of these RNA elements (A and B) are required for protease dimerization and activation. The D element functions as internal polypurine tract during reverse transcription. Peters et al., described the third element (C) as essential for gag expression suggesting that it might serve as an RNA export element for the unspliced genomic transcript.
Results:
Here, we analysed env splicing and demonstrate that the described C element composed of three GAA repeats known to bind SR proteins regulates env splicing, thus balancing the amount of gag/pol mRNAs. Deletion of the C element effectively promotes a splice site switch from a newly identified env splice acceptor to the intrinsically strong downstream localised env 3′ splice acceptor permitting complete splicing of almost all LTR derived transcripts. We provide evidence that repression of this env splice acceptor is a prerequisite for gag expression. This repression is achieved by the C element, resulting in impaired branch point recognition and SF1/mBBP binding. Separating the branch point from the overlapping purine-rich C element, by insertion of only 20 nucleotides, liberated repression and fully restored splicing to the intrinsically strong env 3′ splice site. This indicated that the cis-acting element might repress splicing by blocking the recognition of essential splice site signals.
Conclusions:
The foamy viral purine-rich C element regulates splicing by suppressing the branch point recognition of the strongest env splice acceptor. It is essential for the formation of unspliced gag and singly spliced pol transcripts.
For persistent infections of the mammalian host, African trypanosomes limit their population size by quorum sensing of the parasite-excreted stumpy induction factor (SIF), which induces development to the tsetse-infective stumpy stage. We found that besides this cell density-dependent mechanism, there exists a second path to the stumpy stage that is linked to antigenic variation, the main instrument of parasite virulence. The expression of a second variant surface glycoprotein (VSG) leads to transcriptional attenuation of the VSG expression site (ES) and immediate development to tsetse fly infective stumpy parasites. This path is independent of SIF and solely controlled by the transcriptional status of the ES. In pleomorphic trypanosomes varying degrees of ES-attenuation result in phenotypic plasticity. While full ES-attenuation causes irreversible stumpy development, milder attenuation may open a time window for rescuing an unsuccessful antigenic switch, a scenario that so far has not been considered as important for parasite survival.
The coronal unicondylar fracture of the distal femur (AO 33-B3) is a rare intraarticular injury within the weight bearing area of the knee, initially described by Albert Hoffa in 1904. We report an unusual combination of a Hoffa fracture with lateral patellar dislocation in a young adult. Our patient sustained the injury by a sudden twist of his leg during sports. He presented clinically with knee swelling, dislocation of the patella, and localized tenderness; unable to bare weight. After plane radiograph confirmed the injury, manual reduction of the patella was done by hyperextension of the knee and medialward pressure. Afterwards, a CT scan and MRI were conducted. The injury was surgically treated with lag-screws, locking-plate and MPFL-reconstruction.
Many pathogenic bacteria utilize specialized secretion systems to deliver proteins called effectors into eukaryotic cells for manipulation of host pathways. The vast majority of known effector targets are host proteins, whereas a potential targeting of host nucleic acids remains little explored. There is only one family of effectors known to target DNA directly, and effectors binding host RNA are unknown. Here, we take a two-pronged approach to search for RNA-binding effectors, combining biocomputational prediction of RNA-binding domains (RBDs) in a newly assembled comprehensive dataset of bacterial secreted proteins, and experimental screening for RNA binding in mammalian cells. Only a small subset of effectors were predicted to carry an RBD, indicating that if RNA targeting was common, it would likely involve new types of RBDs. Our experimental evaluation of effectors with predicted RBDs further argues for a general paucity of RNA binding activities amongst bacterial effectors. We obtained evidence that PipB2 and Lpg2844, effector proteins of Salmonella and Legionella species, respectively, may harbor novel biochemical activities. Our study presenting the first systematic evaluation of the RNA-targeting potential of bacterial effectors offers a basis for discussion of whether or not host RNA is a prominent target of secreted bacterial proteins.
In this work, multi-particle quantum optimal control problems are studied in the framework of time-dependent density functional theory (TDDFT).
Quantum control problems are of great importance in both fundamental research and application of atomic and molecular systems. Typical applications are laser induced chemical reactions, nuclear magnetic resonance experiments, and quantum computing.
Theoretically, the problem of how to describe a non-relativistic system of multiple particles is solved by the Schrödinger equation (SE). However, due to the exponential increase in numerical complexity with the number of particles, it is impossible to directly solve the Schrödinger equation for large systems of interest. An efficient and successful approach to overcome this difficulty is the framework of TDDFT and the use of the time-dependent Kohn-Sham (TDKS) equations therein.
This is done by replacing the multi-particle SE with a set of nonlinear single-particle Schrödinger equations that are coupled through an additional potential.
Despite the fact that TDDFT is widely used for physical and quantum chemical calculation and software packages for its use are readily available, its mathematical foundation is still under active development and even fundamental issues remain unproven today.
The main purpose of this thesis is to provide a consistent and rigorous setting for the TDKS equations and of the related optimal control problems.
In the first part of the thesis, the framework of density functional theory (DFT) and TDDFT are introduced. This includes a detailed presentation of the different functional sets forming DFT. Furthermore, the known equivalence of the TDKS system to the original SE problem is further discussed.
To implement the TDDFT framework for multi-particle computations, the TDKS equations provide one of the most successful approaches nowadays. However, only few mathematical results concerning these equations are available and these results do not cover all issues that arise in the formulation of optimal control problems governed by the TDKS model.
It is the purpose of the second part of this thesis to address these issues such as higher regularity of TDKS solutions and the case of weaker requirements on external (control) potentials that are instrumental for the formulation of well-posed TDKS control problems. For this purpose, in this work, existence and uniqueness of TDKS solutions are investigated in the Galerkin framework and using energy estimates for the nonlinear TDKS equations.
In the third part of this thesis, optimal control problems governed by the TDKS model are formulated and investigated. For this purpose, relevant cost functionals that model the purpose of the control are discussed.
Henceforth, TDKS control problems result from the requirement of optimising the given cost functionals subject to the differential constraint given by the TDKS equations. The analysis of these problems is novel and represents one of the main contributions of the present thesis.
In particular, existence of minimizers is proved and their characterization by TDKS optimality systems is discussed in detail.
To this end, Fréchet differentiability of the TDKS model and of the cost functionals is addressed considering \(H^1\) cost of the control.
This part is concluded by deriving the reduced gradient in the \(L^2\) and \(H^1\) inner product.
While the \(L^2\) optimization is widespread in the literature, the choice of the \(H^1\) gradient is motivated in this work by theoretical consideration and by resulting numerical advantages.
The last part of the thesis is devoted to the numerical approximation of the TDKS optimality systems and to their solution by gradient-based optimization techniques.
For the former purpose, Strang time-splitting pseudo-spectral schemes are discussed including a review of some recent theoretical estimates for these schemes and a numerical validation of these estimates.
For the latter purpose, nonlinear (projected) conjugate gradient methods are implemented and are used to validate the theoretical analysis of this thesis with results of numerical experiments with different cost functional settings.
α-Synuclein is a protein implicated in the etiopathogenesis of Parkinson’s disease (PD). AAV1/2-driven overexpression of human mutated A53T-α-synuclein in rat and monkey substantia nigra (SN) induces degeneration of nigral dopaminergic neurons and decreases striatal dopamine and tyrosine hydroxylase (TH). Given certain advantages of the mouse, especially it being amendable to genetic manipulation, translating the AAV1/2-A53T α-synuclein model to mice would be of significant value. AAV1/2-A53T α-synuclein or AAV1/2 empty vector (EV) at a concentration of 5.16 x 10\(^{12}\) gp/ml were unilaterally injected into the right SN of male adult C57BL/6 mice. Post-mortem examinations included immunohistochemistry to analyze nigral α-synuclein, Ser129 phosphorylated α-synuclein and TH expression, striatal dopamine transporter (DAT) levels by autoradiography and dopamine levels by high performance liquid chromatography. At 10 weeks, in AAV1/2-A53T α-synuclein mice there was a 33% reduction in TH+ dopaminergic nigral neurons (P < 0.001), 29% deficit in striatal DAT binding (P < 0.05), 38% and 33% reductions in dopamine (P < 0.001) and DOPAC (P < 0.01) levels and a 60% increase in dopamine turnover (homovanilic acid/dopamine ratio; P < 0.001). Immunofluorescence showed that the AAV1/2-A53T α-synuclein injected mice had widespread nigral and striatal expression of vector-delivered A53T-α-synuclein. Concurrent staining with human PD SN samples using gold standard histological methodology for Lewy pathology detection by proteinase K digestion and application of specific antibody raised against human Lewy body α-synuclein (LB509) and Ser129 phosphorylated α-synuclein (81A) revealed insoluble α-synuclein aggregates in AAV1/2-A53T α-synuclein mice resembling Lewy-like neurites and bodies. In the cylinder test, we observed significant paw use asymmetry in the AAV1/2-A53T α-synuclein group when compared to EV controls at 5 and 9 weeks post injection (P < 0.001; P < 0.05). These data show that unilateral injection of AAV1/2-A53T α-synuclein into the mouse SN leads to persistent motor deficits, neurodegeneration of the nigrostriatal dopaminergic system and development of Lewy-like pathology, thereby reflecting clinical and pathological hallmarks of human PD.
Intracellular pathogenic microorganisms and toxins exploit host cell mechanisms to enter, exert their deleterious effects as well as hijack host nutrition for their development. A potential approach to treat multiple pathogen infections and that should not induce drug resistance is the use of small molecules that target host components. We identifed the compound 1-adamantyl (5-bromo-2-methoxybenzyl) amine (ABMA) from a cell-based high throughput screening for its capacity to protect human cells and mice against ricin toxin without toxicity. This compound efciently protects cells against various toxins and pathogens including viruses, intracellular bacteria and parasite. ABMA provokes Rab7-positive late endosomal compartment accumulation in mammalian cells without affecting other organelles (early endosomes, lysosomes, the Golgi apparatus, the endoplasmic reticulum or the nucleus). As the mechanism of action of ABMA is restricted to host-endosomal compartments, it reduces cell infection by pathogens that depend on this pathway to invade cells. ABMA may represent a novel class of broad-spectrum compounds with therapeutic potential against diverse severe infectious diseases.
Sustained anticipatory anxiety is central to Generalized Anxiety Disorder (GAD). During anticipatory anxiety, phasic threat responding appears to be mediated by the amygdala, while sustained threat responding seems related to the bed nucleus of the stria terminalis (BNST). Although sustained anticipatory anxiety in GAD patients was proposed to be associated with BNST activity alterations, firm evidence is lacking. We aimed to explore temporal characteristics of BNST and amygdala activity during threat anticipation in GAD patients. Nineteen GAD patients and nineteen healthy controls (HC) underwent functional magnetic resonance imaging (fMRI) during a temporally unpredictable threat anticipation paradigm. We defined phasic and a systematic variation of sustained response models for blood oxygen level-dependent responses during threat anticipation, to disentangle temporally dissociable involvement of the BNST and the amygdala. GAD patients relative to HC responded with increased phasic amygdala activity to onset of threat anticipation and with elevated sustained BNST activity that was delayed relative to the onset of threat anticipation. Both the amygdala and the BNST displayed altered responses during threat anticipation in GAD patients, albeit with different time courses. The results for the BNST activation hint towards its role in sustained threat responding, and contribute to a deeper understanding of pathological sustained anticipatory anxiety in GAD.
Background:
The integrity of the flexor tendon pulley apparatus is crucial for unimpaired function of the digits. Although secondary reconstruction is an established procedure in multi-pulley injuries, acute reconstruction of isolated, closed pulley ruptures is a rare occurrence. There are 3 factors influencing the functional outcome of a reconstruction: gapping distance between tendon and bone (E-space), bulkiness of the reconstruction, and stability. As direct repair is rarely done, grafts are used to reinforce the pulley. An advantage of the first extensor retinaculum graft is the synovial coating providing the possibility to be used both as a direct graft with synovial coating or as an onlay graft after removal of the synovia when the native synovial layer is present.
Methods:
A graft from the first dorsal extensor compartment is used as an onlay graft to reinforce the sutured A4 pulley. This technique allows reconstruction of the original dimensions of the pulley system while stability is ensured by anchoring the onlay graft to the bony insertions of the pulley.
Results:
Anatomical reconstruction can be achieved with this method. The measured E-space remained 0 mm throughout the recovery, while the graft incorporated as a slim reinforcement of the pulley, displaying no bulkiness.
Conclusions:
The ideal reconstruction should provide synovial coating and sufficient strength with minimal bulk. Early reconstruction using an onlay graft offers these options. The native synovial lining is preserved and the graft is used to reinforce the pulley.
Niemann–Pick type C disease (NP-C) presents with heterogeneous neurological and psychiatric symptoms. Adult onset is rare and possibly underdiagnosed due to frequent lack of specific and obvious key symptoms. For both early and adolescent/adult onset, the available data from studies and case reports describe a positive effect of Miglustat (symptom relief or stabilization). However, due to the low frequency of NP-C, experience with this therapy is still limited. We describe two adult-onset cases of NP-C. In both cases, vertical supranuclear gaze palsy was not recognized at symptom onset. Correct diagnosis was delayed from onset of symptoms by more than 10 years. The video demonstrates the broad spectrum of symptoms in later stages of the disease. Compared with published data, the treatment outcome observed in our cases after delayed initiation of Miglustat therapy was disappointing, with continuing disease progression in both cases. Thus, early treatment initiation could be necessary to achieve a good symptomatic effect. Hence, early biochemical testing for NP-C should be considered in patients suffering from atypical neurological/neuropsychological and psychiatric symptoms, even in cases of uncertainty.
The progress which has been made in semiconductor chip production in recent years enables a multitude of cores on a single die. However, due to further decreasing structure sizes, fault tolerance and energy consumption will represent key challenges. Furthermore, an efficient communication infrastructure is indispensable due to the high parallelism at those systems. The predominant communication system at such highly parallel systems is a Network on Chip (NoC). The focus of this thesis is on NoCs which are based on deflection routing. In this context, contributions are made to two domains, fault tolerance and dimensioning of the optimal link width. Both aspects are essential for the application of reliable, energy efficient, and deflection routing based NoCs.
It is expected that future semiconductor systems have to cope with high fault probabilities. The inherently given high connectivity of most NoC topologies can be exploited to tolerate the breakdown of links and other components. In this thesis, a fault-tolerant router architecture has been developed, which stands out for the deployed interconnection architecture and the method to overcome complex fault situations. The presented simulation results show, all data packets arrive at their destination, even at high fault probabilities. In contrast to routing table based architectures, the hardware costs of the herein presented architecture are lower and, in particular, independent of the number of components in the network.
Besides fault tolerance, hardware costs and energy efficiency are of great importance. The utilized link width has a decisive influence on these aspects. In particular, at deflection routing based NoCs, over- and under-sizing of the link width leads to unnecessary high hardware costs and bad performance, respectively. In the second part of this thesis, the optimal link width at deflection routing based NoCs is investigated. Additionally, a method to reduce the link width is introduced. Simulation and synthesis results show, the herein presented method allows a significant reduction of hardware costs at comparable performance.
Affective and cognitive behavior in the alpha-galactosidase A deficient mouse model of Fabry disease
(2017)
Fabry disease is an X-linked inherited lysosomal storage disorder with intracellular accumulation of globotriaosylceramide (Gb3) due to α-galactosidase A (α-Gal A) deficiency. Fabry patients frequently report of anxiety, depression, and impaired cognitive function. We characterized affective and cognitive phenotype of male mice with α-Gal A deficiency (Fabry KO) and compared results with those of age-matched male wildtype (WT) littermates. Young (3 months) and old (≥ 18 months) mice were tested in the naïve state and after i.pl. injection of complete Freund`s adjuvant (CFA) as an inflammatory pain model. We used the elevated plus maze (EPM), the light-dark box (LDB) and the open field test (OF) to investigate anxiety-like behavior. The forced swim test (FST) and Morris water maze (MWM) were applied to assess depressive-like and learning behavior. The EPM test revealed no intergroup difference for anxiety-like behavior in naïve young and old Fabry KO mice compared to WT littermates, except for longer time spent in open arms of the EPM for young WT mice compared to young Fabry KO mice (p<0.05). After CFA injection, young Fabry KO mice showed increased anxiety-like behavior compared to young WT littermates (p<0.05) and naïve young Fabry KO mice (p<0.05) in the EPM as reflected by shorter time spent in EPM open arms. There were no relevant differences in the LDB and the OF test, except for longer time spent in the center zone of the OF by young WT mice compared to young Fabry KO mice (p<0.05). Complementary to this, depression-like and learning behavior were not different between genotypes and age-groups, except for the expectedly lower memory performance in older age-groups compared to young mice. Our results indicate that genetic influences on affective and cognitive symptoms in FD may be of subordinate relevance, drawing attention to potential influences of environmental and epigenetic factors.
Advanced LIGO detected a significant gravitational wave signal (GW170104) originating from the coalescence of two black holes during the second observation run on January 4th, 2017. An all-sky high-energy neutrino follow-up search has been made using data from the Antares neutrino telescope, including both upgoing and downgoing events in two separate analyses. No neutrino candidates were found within ±500 s around the GW event time nor any time clustering of events over an extended time window of ±3 months. The non-detection is used to constrain isotropic-equivalent high-energy neutrino emission from GW170104 to less than ∼ 1.2 × \(10^{55}\) erg for a \(E^{−2}\) spectrum. This constraint is valid in the energy range corresponding to the 5–95% quantiles of the neutrino flux [3.2 TeV; 3.6 PeV], if the GW emitter was below the Antares horizon at the alert time.
Background:
Traumatic brain injury (TBI) is a devastating neurological condition and a frequent cause of permanent disability. Posttraumatic inflammation and brain edema formation, two pathological key events contributing to secondary brain injury, are mediated by the contact-kinin system. Activation of this pathway in the plasma is triggered by activated factor XII. Hence, we set out to study in detail the influence of activated factor XII on the abovementioned pathophysiological features of TBI.
Methods:
Using a cortical cryogenic lesion model in mice, we investigated the impact of genetic deficiency of factor XII and inhibition of activated factor XII with a single bolus injection of recombinant human albumin-fused Infestin-4 on the release of bradykinin, the brain lesion size, and contact-kinin system-dependent pathological events. We determined protein levels of bradykinin, intracellular adhesion molecule-1, CC-chemokine ligand 2, and interleukin-1β by enzyme-linked immunosorbent assays and mRNA levels of genes related to inflammation by quantitative real-time PCR. Brain lesion size was determined by tetrazolium chloride staining. Furthermore, protein levels of the tight junction protein occludin, integrity of the blood-brain barrier, and brain water content were assessed by Western blot analysis, extravasated Evans Blue dye, and the wet weight-dry weight method, respectively. Infiltration of neutrophils and microglia/activated macrophages into the injured brain lesions was quantified by immunohistological stainings.
Results:
We show that both genetic deficiency of factor XII and inhibition of activated factor XII in mice diminish brain injury-induced bradykinin release by the contact-kinin system and minimize brain lesion size, blood-brain barrier leakage, brain edema formation, and inflammation in our brain injury model.
Conclusions:
Stimulation of bradykinin release by activated factor XII probably plays a prominent role in expanding secondary brain damage by promoting brain edema formation and inflammation. Pharmacological blocking of activated factor XII could be a useful therapeutic principle in the treatment of TBI-associated pathologic processes by alleviating posttraumatic inflammation and brain edema formation.
Theory predicts that males and females should often join the mating pool at different times (sexual dimorphism in timing of emergence [SDT]) as the degree of SDT affects female mating success. We utilize an analytical model to explore (1) how important SDT is for female mating success, (2) how mating success might change if either sex's mortality (abruptly) increases, and (3) to what degree evolutionary responses in SDT may be able to mitigate the consequences of such mortality increase. Increasing male pre‐mating mortality has a non‐linear effect on the fraction of females mated: The effect is initially weak, but at some critical level a further increase in male mortality has a stronger effect than a similar increase in female mortality. Such a change is expected to impose selection for reduced SDT. Increasing mortality during the mating season has always a stronger effect on female mating success if the mortality affects the sex that emerges first. This bias results from the fact that enhancing mortality of the earlier emerging sex reduces female–male encounter rates. However, an evolutionary response in SDT may effectively mitigate such consequences. Further, if considered independently for females and males, the predicted evolutionary response in SDT could be quite dissimilar. The difference between female and male evolutionary response in SDT leads to marked differences in the fraction of fertilized females under certain conditions. Our model may provide general guidelines for improving harvesting of populations, conservation management of rare species under altered environmental conditions, or maintaining long‐term efficiency of pest‐control measures.
The opportunistic fungal pathogen Candida albicans frequently produces genetically altered variants to adapt to environmental changes and new host niches in the course of its life-long association with the human host. Gain-of-function mutations in zinc cluster transcription factors, which result in the constitutive upregulation of their target genes, are a common cause of acquired resistance to the widely used antifungal drug fluconazole, especially during long-term therapy of oropharyngeal candidiasis. In this study, we investigated if C. albicans also can develop resistance to the antimicrobial peptide histatin 5, which is secreted in the saliva of humans to protect the oral mucosa from pathogenic microbes. As histatin 5 has been shown to be transported out of C. albicans cells by the Flu1 efflux pump, we screened a library of C. albicans strains that contain artificially activated forms of all zinc cluster transcription factors of this fungus for increased FLU1 expression. We found that a hyperactive Mrr1, which confers fluconazole resistance by upregulating the multidrug efflux pump MDR1 and other genes, also causes FLU1 overexpression. Similarly to the artificially activated Mrr1, naturally occurring gain-of-function mutations in this transcription factor also caused FLU1 upregulation and increased histatin 5 resistance. Surprisingly, however, Mrr1-mediated histatin 5 resistance was mainly caused by the upregulation of MDR1 instead of FLU1, revealing a previously unrecognized function of the Mdr1 efflux pump. Fluconazole-resistant clinical C. albicans isolates with different Mrr1 gain-of-function mutations were less efficiently killed by histatin 5, and this phenotype was reverted when MRR1 was deleted. Therefore, antimycotic therapy can promote the evolution of strains that, as a consequence of drug resistance mutations, simultaneously have acquired increased resistance against an innate host defense mechanism and are thereby better adapted to certain host niches.
Host–microbe interactions are the key to understand why and how microbes inhabit specific environments. With the scientific fields of microbial genomics and metagenomics, evolving on an unprecedented scale, one is able to gain insights in these interactions on a molecular and ecological level. The goal of this PhD thesis was to make (meta–)genomic data accessible, integrate it in a comparative manner and to gain comprehensive taxonomic and functional insights into bacterial strains and communities derived from two different environments: the phyllosphere of Arabidopsis thaliana and the mesohyl interior of marine sponges.
This thesis focused first on the de novo assembly of bacterial genomes. A 5–step protocol was developed, each step including a quality control. The examination of different assembly software in a comparative way identified SPAdes as most suitable. The protocol enables the user to chose the best tailored assembly. Contamination issues were solved by an initial filtering of the data and methods normally used for the binning of metagenomic datasets. This step is missed in many published assembly pipelines. The described protocol offers assemblies of high quality ready for downstream analysis.
Subsequently, assemblies generated with the developed protocol were annotated and explored
in terms of their function. In a first study, the genome of a phyllosphere bacterium, Williamsia sp. ARP1, was analyzed, offering many adaptions to the leaf habitat: it can deal with temperature shifts, react to oxygen species, produces mycosporins as protection against UV–light, and is able to uptake photosynthates. Further, its taxonomic position within the Actinomycetales was infered from 16S rRNA and comparative genomics showing the close relation between the genera Williamsia and Gordonia.
In a second study, six sponge–derived actinomycete genomes were investigated for secondary metabolism. By use of state–of–the–art software, these strains exhibited numerous gene clusters, mostly linked to polykethide synthases, non–ribosomal peptide synthesis, terpenes, fatty acids and saccharides. Subsequent predictions on these clusters offered a great variety of possible produced compounds with antibiotic, antifungal or anti–cancer activity. These analysis highlight the potential for the synthesis of natural products and the use of genomic data as screening toolkit.
In a last study, three sponge–derived and one seawater metagenomes were functionally compared. Different signatures regarding the microbial composition and GC–distribution were observed between the two environments. With a focus on bacerial defense systems, the data indicates a pronounced repertoire of sponge associated bacteria for bacterial defense systems, in particular, Clustered Regularly Interspaced Short Palindromic Repeats, restriction modification system, DNA phosphorothioation and phage growth limitation. In addition, characterizing genes for secondary metabolite cluster differed between sponge and seawater microbiomes. Moreover, a variety of Type I polyketide synthases were only found within the sponge microbiomes. With that, metagenomics are shown to be a useful tool for the screening of secondary metabolite genes. Furthermore, enriched defense systems are highlighted as feature of sponge-associated microbes and marks them as a selective trait.
Epigenetic alterations may contribute to the generation of cancer cells in a multi-step process of tumorigenesis following irradiation of normal body cells. Primary human fibroblasts with intact cell cycle checkpoints were used as a model to test whether X-ray irradiation with 2 and 4 Gray induces direct epigenetic effects (within the first cell cycle) in the exposed cells. ELISA-based fluorometric assays were consistent with slightly reduced global DNA methylation and hydroxymethylation, however the observed between-group differences were usually not significant. Similarly, bisulfite pyrosequencing of interspersed LINE-1 repeats and centromeric α-satellite DNA did not detect significant methylation differences between irradiated and non-irradiated cultures. Methylation of interspersed ALU repeats appeared to be slightly increased (one percentage point; p = 0.01) at 6 h after irradiation with 4 Gy. Single-cell analysis showed comparable variations in repeat methylation among individual cells in both irradiated and control cultures. Radiation-induced changes in global repeat methylation, if any, were much smaller than methylation variation between different fibroblast strains. Interestingly, α-satellite DNA methylation positively correlated with gestational age. Finally, 450K methylation arrays mainly targeting genes and CpG islands were used for global DNA methylation analysis. There were no detectable methylation differences in genic (promoter, 5' UTR, first exon, gene body, 3' UTR) and intergenic regions between irradiated and control fibroblast cultures. Although we cannot exclude minor effects, i.e. on individual CpG sites, collectively our data suggest that global DNA methylation remains rather stable in irradiated normal body cells in the early phase of DNA damage response.
Analysis of host microRNA function uncovers a role for miR-29b-2-5p in Shigella capture by filopodia
(2017)
MicroRNAs play an important role in the interplay between bacterial pathogens and host cells, participating as host defense mechanisms, as well as exploited by bacteria to subvert host cellular functions. Here, we show that microRNAs modulate infection by Shigella flexneri, a major causative agent of bacillary dysentery in humans. Specifically, we characterize the dual regulatory role of miR-29b-2-5p during infection, showing that this microRNA strongly favors Shigella infection by promoting both bacterial binding to host cells and intracellular replication. Using a combination of transcriptome analysis and targeted high-content RNAi screening, we identify UNC5C as a direct target of miR-29b-2-5p and show its pivotal role in the modulation of Shigella binding to host cells. MiR-29b-2-5p, through repression of UNC5C, strongly enhances filopodia formation thus increasing Shigella capture and promoting bacterial invasion. The increase of filopodia formation mediated by miR-29b-2-5p is dependent on RhoF and Cdc42 Rho-GTPases. Interestingly, the levels of miR-29b-2-5p, but not of other mature microRNAs from the same precursor, are decreased upon Shigella replication at late times post-infection, through degradation of the mature microRNA by the exonuclease PNPT1. While the relatively high basal levels of miR-29b-2-5p at the start of infection ensure efficient Shigella capture by host cell filopodia, dampening of miR-29b-2-5p levels later during infection may constitute a bacterial strategy to favor a balanced intracellular replication to avoid premature cell death and favor dissemination to neighboring cells, or alternatively, part of the host response to counteract Shigella infection. Overall, these findings reveal a previously unappreciated role of microRNAs, and in particular miR-29b-2-5p, in the interaction of Shigella with host cells.
The electroweak production and subsequent decay of single top quarks in the \(t\)-channel is determined by the properties of the \({Wtb}\) vertex, which can be described by the complex parameters of an effective Lagrangian. An analysis of a triple-differential decay rate in \(t\)-channel production is used to simultaneously determine five generalised helicity fractions and phases, as well as the polarisation of the produced top quark. The complex parameters are then constrained. This analysis is based on 20.2 fb\(^{−1}\) of proton-proton collision data at a centre-of-mass energy of 8 TeV collected with the ATLAS detector at the LHC. The fraction of decays containing transversely polarised \(W\) bosons is measured to be \(f_1\) = 0.30 ± 0.05. The phase between amplitudes for transversely and longitudinally polarised \(W\) bosons recoiling against left-handed \(b\)-quarks is measured to be \(\delta\)_ = 0.002\(\pi^{+0.016\pi}_{+0.017\pi}\), giving no indication of CP violation. The fractions of longitudinal or transverse \(W\) bosons accompanied by right-handed \(b\)-quarks are also constrained. Based on these measurements, limits are placed at 95% CL on the ratio of the complex coupling parameters Re [\({g_R/V_L}\) \(\in\) [−0.12, 0.17] and Im [\({g_R/V_L}\) \(\in\) [−0.07, 0.06]. Constraints are also placed on the ratios |\({V_R}/{V_L}\)| and |\({g_L}/{V_L}\)|. In addition, the polarisation of single top quarks in the \(t\)-channel is constrained to be \(P\) > 0.72 (95% CL). None of the above measurements make assumptions about the value of any of the other parameters or couplings and all of them are in agreement with the Standard Model.
The current dissertation addresses the analysis of technology-enhanced learning processes by using Process Mining techniques. For this purpose, students’ coded think-aloud data served as the measurement of the learning process, in order to assess the potential of this analysis method for evaluating the impact of instructional support.
The increasing use of digital media in higher education and further educational sectors enables new potentials. However, it also poses new challenges to students, especially regarding the self-regulation of their learning process. To help students with optimally making progress towards their learning goals, instructional support is provided during learning. Besides the use of questionnaires and tests for the assessment of learning, researchers make use increasingly of process data to evaluate the effects of provided support. The analysis of observed behavioral traces while learning (e.g., log files, eye movements, verbal reports) allows detailed insights into the student’s activities as well as the impact of interventions on the learning process. However, new analytical challenges emerge, especially when going beyond the analysis of pure frequencies of observed events. For example, the question how to deal with temporal dynamics and sequences of learning activities arises. Against this background, the current dissertation concentrates on the application of Process Mining techniques for the detailed analysis of learning processes. In particular, the focus is on the additional value of this approach in comparison to a frequency-based analysis, and therefore on the potential of Process Mining for the evaluation of instructional support.
An extensive laboratory study with 70 university students, which was conducted to investigate the impact of a support measure, served as the basis for pursuing the research agenda of this dissertation. Metacognitive prompts supported students in the experimental group (n = 35) during a 40-minute hypermedia learning session; whereas the control group (n = 35) received no support. Approximately three weeks later, all students participated in another learning session; however, this time all students learned without any help. The participants were instructed to verbalize their learning activities concurrently while learning. In the three analyses of this dissertation, the coded think aloud data were examined in detail by using frequency-based methods as well as Process Mining techniques.
The first analysis addressed the comparison of the learning activities between the experimental and control groups during the first learning session. This study concentrated on the research questions whether metacognitive prompting increases the number of metacognitive learning activities, whether a higher number of these learning activities corresponds with learning outcome (mediation), and which differences regarding the sequential structure of learning activities can be revealed. The second analysis investigated the impact of the individual prompts as well as the conditions of their effectiveness on the micro level. In addition to Process Mining, we used a data mining approach to compare the findings of both analysis methods. More specifically, we classified the prompts by their effectiveness, and we examined the learning activities preceding and following the presentation of instructional support. Finally, the third analysis considered the long-term effects of metacognitive prompting on the learning process during another learning session without support. It was the key objective of this study to examine which fostered learning activities and process patterns remained stable during the second learning session.
Overall, all three analyses indicated the additional value of Process Mining in comparison to a frequency-based analysis. Especially when conceptualizing the learning process as a dynamic sequence of multiple activities, Process Mining allows identifying regulatory loops and crucial routing points of the process. These findings might contribute to optimizing intervention strategies. However, before drawing conclusions for the design of instructional support based on the revealed process patterns, additional analyses need to investigate the generalizability of results. Moreover, the application of Process Mining remains challenging because guidelines for analytical decisions and parameter settings in technology-enhanced learning context are currently missing. Therefore, future studies need to examine further the potential of Process Mining as well as related analysis methods to provide researchers with concrete recommendations for use. Nevertheless, the application of Process Mining techniques can already contribute to advance the understanding of the impact of instructional support through the use of fine-grained process data.
A striking feature of the metabolite profile of \(Ancistrocladus\) \(likoko\) (Ancistrocladaceae) is the exclusive production of 5,8\('\)-linked naphthylisoquinoline alkaloids varying in their OMe/OH substitution patterns and in the hydrogenation degree in their isoquinoline portions. Here we present nine new compounds of this coupling type isolated from the twigs of this remarkable Central African liana. Three of them, the ancistrolikokines E (9), E\(_2\) (10), and F (11), are the first 5,8\('\)-linked naphthyldihydroisoquinolines found in nature with \(R\)-configuration at C-3. The fourth new metabolite, ancistrolikokine G (12), is so far the only representative of the 5,8\('\)-coupling type that belongs to the very rare group of alkaloids with a fully dehydrogenated isoquinoline portion. Moreover, five new \(N\)-methylated naphthyltetrahydroisoquinolines, named ancistrolikokines A\(_2\) (13), A\(_3\) (14), C\(_2\) (5), H (15), and H\(_2\) (16) are presented, along with six known 5,8\('\)-linked alkaloids, previously identified in related African \(Ancistrocladus\) species, now found for the first time in \(A.\) \(likoko\). The structural elucidation was achieved by spectroscopic analysis (HRESIMS, 1D and 2D NMR) and by chemical (oxidative degradation) and chiroptical (electronic circular dichroism) methods. The new ancistrolikokines showed moderate to good preferential cytotoxic activities towards pancreatic PANC-1 cells in nutrient-deprived medium (NDM), without causing toxicity under normal, nutrient-rich conditions, with ancistrolikokine H\(_2\) (16) being the most potent compound.
Anionic Adducts
Sp2-sp3 tetraalkoxy diboron compounds have gained attention due to the development of new, synthetically useful catalytic reactions either with or without transition-metals. Lewis-base adducts of the diboron(4) compounds were suggested as possible intermediates in Cu catalyzed borylation reactions some time ago. However, intermolecular adducts of tetraalkoxy diboron compounds have not been studied yet in great detail. In preliminary studies, we have synthesized a series of anionic sp2-sp3 adducts of B2pin2 with alkoxy-groups (L = [OMe]–, [OtBu]–), a phenoxy-group (L = [4-tBuC6H4O]–) and fluoride (L = [F]–, with [nBu4N]+ as the counter ion) as Lewis-bases.
Neutral Adducts
Since their isolation and characterization, applications of N-heterocyclic carbenes (NHCs) and related molecules, e.g., cyclic alkylaminocarbenes (CAACs) and acyclic diaminocarbenes (aDCs), have grown rapidly. Their use as ligands in homogeneous catalysis and directly in organocatalysis, including recently developed borylation reactions, is now well established. Recently, several examples of ring expansion reactions (RER) involving NHCs were reported to take place at elevated temperatures, involving Be, B, and Si.
Furthermore, preliminary studies in the group of Marder et al. showed the presence of neutral sp2-sp3 diboron compounds with B2pin2 and the NHC Cy2Im. In this work, we focused on the synthesis and characterization of further neutral sp2-sp3 as well as sp3-sp3 diboron adducts with B2cat2 and B2neop2 and different NHCs. Whereas the mono-NHC adduct is stable for several hours at temperatures up to 60 °C, the bis-NHC adducts undergo thermally induced rearrangement to form the ring expanded products compound 26 and 27. B2neop2 is much more reactive than B2cat2 giving ring expanded product 29 at room temperature in quantitative yields, demonstrating that NHC ring expansion and B–B bond cleavage can be very facile processes.
Whereas the mono-NHC adduct is stable for several hours at temperatures up to 60 °C, the bis-NHC adducts undergo thermally induced rearrangement to form the ring expanded products compound 26 and 27. B2neop2 is much more reactive than B2cat2 giving ring expanded product 29 at room temperature in quantitative yields, demonstrating that NHC ring expansion and B–B bond cleavage can be very facile processes.
Certain fatty acids and sphingoid bases found at mucosal surfaces are known to have antibacterial activity and are thought to play a more direct role in innate immunity against bacterial infections. Herein, we analysed the antibacterial activity of sphingolipids, including the sphingoid base sphingosine as well as short-chain C\(_{6}\) and long-chain C\(_{16}\)-ceramides and azido-functionalized ceramide analogs against pathogenic Neisseriae. Determination of the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) demonstrated that short-chain ceramides and a ω-azido-functionalized C\(_{6}\)-ceramide were active against Neisseria meningitidis and N. gonorrhoeae, whereas they were inactive against Escherichia coli and Staphylococcus aureus. Kinetic assays showed that killing of N. meningitidis occurred within 2 h with ω–azido-C\(_{6}\)-ceramide at 1 X the MIC. Of note, at a bactericidal concentration, ω–azido-C\(_{6}\)-ceramide had no significant toxic effect on host cells. Moreover, lipid uptake and localization was studied by flow cytometry and confocal laser scanning microscopy (CLSM) and revealed a rapid uptake by bacteria within 5 min. CLSM and super-resolution fluorescence imaging by direct stochastic optical reconstruction microscopy demonstrated homogeneous distribution of ceramide analogs in the bacterial membrane. Taken together, these data demonstrate the potent bactericidal activity of sphingosine and synthetic short-chain ceramide analogs against pathogenic Neisseriae.
Linear, dimeric, tetrameric, and cyclic peptides derived from lactoferricin B, containing the RRWQWR motif, were designed, synthesized, purified, and characterized using RP-HPLC chromatography and MALDI-TOF mass spectrometry. The antibacterial activity of the designed peptides against E. coli (ATCC 11775 and 25922) and their cytotoxic effect against MDA-MB-468 and MDA-MB-231 breast cancer cell lines were evaluated. Dimeric and tetrameric peptides showed higher antibacterial activity in both bacteria strains than linear peptides. The dimeric peptide (RRWQWR)\(_2\)K-Ahx exhibited the highest antibacterial activity against the tested bacterial strains. Furthermore, the peptides with high antibacterial activity exhibited significant cytotoxic effect against the tested breast cancer cell lines. This cytotoxic effect was fast and dependent on the peptide concentration. The tetrameric molecule containing RRWQWR motif has an optimal cytotoxic effect at a concentration of 22 µM. The evaluated dimeric and tetrameric peptides could be considered as candidates for developing new therapeutic agents against breast cancer. Polyvalence of linear sequences could be considered as a novel and versatile strategy for obtaining molecules with high anticancer activity.
Antimicrobial resistance is a growing global concern in human and veterinary medicine, with an ever-increasing void in the arsenal of clinicians. Novel classes of compounds including carbon monoxoide-releasing molecules (CORMs), for example the light-activated metal complex [Mn(CO)\(_3\)(tpa-\(\kappa^{3}N\))]Br, could be used as alternatives/to supplement traditional antibacterials. Avian pathogenic \(Escherichia\) \(coli\) (APEC) represent a large reservoir of antibiotic resistance and can cause serious clinical disease in poultry, with potential as zoonotic pathogens, due to shared serotypes and virulence factors with human pathogenic \(E.\) \(coli\). The \(in\) \(vitro\) activity of [Mn(CO)\(_3\)(tpa-\(\kappa^{3}N\))]Br against multidrug-resistant APECs was assessed via broth microtitre dilution assays and synergy testing with colistin performed using checkerboard and time-kill assays. \(In\) \(vivo\) antibacterial activity of [Mn(CO)\(_3\)(tpa-\(\kappa^{3}N\))]Br alone and in combination with colistin was determined using the \(Galleria\) \(mellonella\) wax moth larvae model. Animals were monitored for life/death, melanisation and bacterial numbers enumerated from larval haemolymph. \(In\) \(vitro\) testing produced relatively high [Mn(CO)\(_3\)(tpa-\(\kappa^{3}N\))]Br minimum inhibitory concentrations (MICs) of 1024 mg/L. However, its activity was significantly increased with the addition of colistin, bringing MICs down to \(\geq\)32 mg/L. This synergy was confirmed in time-kill assays. \(In\) \(vivo\) assays showed that the combination of [Mn(CO)\(_3\)(tpa-\(\kappa^{3}N\))]Br with colistin produced superior bacterial killing and significantly increased larval survival. In both \(in\) \(vitro\) and \(in\) \(vivo\) assays light activation was not required for antibacterial activity. This data supports further evaluation of [Mn(CO)\(_3\)(tpa-\(\kappa^{3}N\))]Br as a potential agent for treatment of systemic infections in humans and animals, when used with permeabilising agents such as colistin.
Three unusual heterodimeric naphthylisoquinoline alkaloids, named ealapasamines A-C (1–3), were isolated from the leaves of the tropical plant Ancistrocladus ealaensis J. Léonard. These ‘mixed’, constitutionally unsymmetric dimers are the first stereochemically fully assigned cross-coupling products of a 5,8′- and a 7,8′-coupled naphthylisoquinoline linked via C-6′ in both naphthalene portions. So far, only two other West and Central Ancistrocladus species were known to produce dimers with a central 6,6″-axis, yet, in contrast to the ealapasamines, usually consisting of two 5,8′-coupled monomers, like e.g., in michellamine B. The new dimers 1–3 contain six elements of chirality, four stereogenic centers and the two outer axes, while the central biaryl axis is configurationally unstable. The elucidation of the complete stereostructures of the ealapasamines was achieved by the interplay of spectroscopic methods including HRESIMS, 1D and 2D NMR (in particular ROESY measurements), in combination with chemical (oxidative degradation) and chiroptical (electronic circular dichroism) investigations. The ealapasamines A-C display high antiplasmodial activities with excellent half-maximum inhibition concentration values in the low nanomolar range.
Neoplasms of the skin represent the most frequent tumors worldwide; fortunately, most of them are benign or semi-malignant and well treatable. However, the two most aggressive and deadly forms of malignant skin-neoplasms are melanoma and Merkel cell carcinoma (MCC), being responsible for more than 90% of skin-cancer related deaths. The last decade has yielded enormous progress in melanoma therapy with the advent of targeted therapies, like BRAF or MEK inhibitors, and immune-stimulating therapies, using checkpoint antibodies targeting CTLA- 4, PD-1 or PD-L1. Very recent studies suggest that also MCC patients benefit from a treatment with checkpoint antibodies. Nevertheless, in an advanced metastatic stage, a cure for both of these aggressive malignancies is still hard to achieve: while only a subset of patients experience durable benefit from the immune-based therapies, the widely applicable targeted therapies struggle with development of resistances that inevitably occur in most patients, and finally lead to their death. The four articles included in this thesis addressed current questions concerning therapy and carcinogenesis of melanoma and MCC. Moreover, they are discussed in the light of the up-to-date research regarding targeted and immune-based therapies. In article I we demonstrated that besides apoptosis, MAPK pathway inhibition in BRAF-mutated melanoma cells also induces senescence, a permanent cell cycle arrest. These cells may provide a source for relapse, as even permanently arrested cancer cells can contribute to a pro-tumorigenic milieu. To identify molecular factors determining the differential response, we established M14 melanoma cell line derived single cell clones that either undergo cell death or arrest when treated with BRAF/MEK inhibitors. Using these single cell clones, we demonstrated in article IV that downregulation of the pro-apoptotic BH3-only protein BIK via epigenetic silencing is involved in apoptosis deficiency, which can be overcome by HDAC inhibitors. These observations provide a possible explanation for the lack of a complete and durable response to MAPK inhibitor treatment in melanoma patients, and suggest the application of HDAC inhibitors as a complimentary therapy to MAPK pathway inhibition. Concerning MCC, we scrutinized the interactions between the Merkel cell polyomavirus’ (MCV) T antigens (TA) and the tumor suppressors p53 and Rb in article II and III, respectively. In article III, we demonstrated that the cell cycle master regulator Rb is the crucial target of MCV large T (LT), while it - in contrast to other polyomavirus LTs - exhibits much lower affinity to the related proteins p107 and p130. Knockdown of MCV LT led to proliferation arrest in MCC cells, which can be rescued by knockdown of Rb, but not by knockdown of p107 and p130. Contrary to Rb, restriction of p53 in MCC seems to be independent of the MCV TAs, as we demonstrated in article II. In conclusion, the presented thesis has revealed new molecular details, regarding the response of melanoma cells towards an important treatment modality and the mechanisms of viral carcinogenesis in MCC.
RNA-binding proteins (RBPs) have been established as core components of several post-transcriptional gene regulation mechanisms. Experimental techniques such as cross-linking and co-immunoprecipitation have enabled the identification of RBPs, RNA-binding domains (RBDs) and their regulatory roles in the eukaryotic species such as human and yeast in large-scale. In contrast, our knowledge of the number and potential diversity of RBPs in bacteria is poorer due to the technical challenges associated with the existing global screening approaches. We introduce APRICOT, a computational pipeline for the sequence-based identification and characterization of proteins using RBDs known from experimental studies. The pipeline identifies functional motifs in protein sequences using position-specific scoring matrices and Hidden Markov Models of the functional domains and statistically scores them based on a series of sequence-based features. Subsequently, APRICOT identifies putative RBPs and characterizes them by several biological properties. Here we demonstrate the application and adaptability of the pipeline on large-scale protein sets, including the bacterial proteome of Escherichia coli. APRICOT showed better performance on various datasets compared to other existing tools for the sequence-based prediction of RBPs by achieving an average sensitivity and specificity of 0.90 and 0.91 respectively. The command-line tool and its documentation are available at https://pypi.python.org/pypi/bio-apricot.
This thesis contributes to several issues in the context of SDN and NFV, with an emphasis on performance and management.
The main contributions are guide lines for operators migrating to software-based networks, as well as an analytical model for the packet processing in a Linux system using the Kernel NAPI.
Although the Letter of Aristeas mentions the translation of the Jewish nomos into Greek, it is striking that worship is not a fundamental theme of this writing. Nevertheless, six passages present acts of worship, which recount worship from different perspectives: Aristeas prays to God and explains his “Greek” idea of worship (Let. Aris. 17), whereas in Let. Aris. 132-140 the high priest explains the Jewish concept of worship. Sacrifices and prayers at the temple in Jerusalem for the Ptolemaic royal house are told in Let. Aris. 45, while at the Ptolemaic court in Alexandria one of the Jewish scholars prays at the beginning of the symposium (Let. Aris. 184-186). Then the daily prayer of the Jewish scholars are recounted in Let. Aris. 305-306 and finally the Ptolemaic king performs a proskynesis before the law at the end of the letter and thereby accepts the translation (Let. Aris. 317).
Background:
Local aortic pulse wave velocity (PWV) is a measure for vascular stiffness and has a predictive value for cardiovascular events. Ultra high field CMR scanners allow the quantification of local PWV in mice, however these systems are yet unable to monitor the distribution of local elasticities.
Methods:
In the present study we provide a new accelerated method to quantify local aortic PWV in mice with phase-contrast cardiovascular magnetic resonance imaging (PC-CMR) at 17.6 T. Based on a k-t BLAST (Broad-use Linear Acquisition Speed-up Technique) undersampling scheme, total measurement time could be reduced by a factor of 6. The fast data acquisition enables to quantify the local PWV at several locations along the aortic blood vessel based on the evaluation of local temporal changes in blood flow and vessel cross sectional area. To speed up post processing and to eliminate operator bias, we introduce a new semi-automatic segmentation algorithm to quantify cross-sectional areas of the aortic vessel. The new methods were applied in 10 eight-month-old mice (4 C57BL/6J-mice and 6 ApoE\(^{(-/-)}\)-mice) at 12 adjacent locations along the abdominal aorta.
Results:
Accelerated data acquisition and semi-automatic post-processing delivered reliable measures for the local PWV, similiar to those obtained with full data sampling and manual segmentation. No statistically significant differences of the mean values could be detected for the different measurement approaches. Mean PWV values were elevated for the ApoE\(^{(-/-)}\)-group compared to the C57BL/6J-group (3.5 ± 0.7 m/s vs. 2.2 ± 0.4 m/s, p < 0.01). A more heterogeneous PWV-distribution in the ApoE \(^{(-/-)}\)-animals could be observed compared to the C57BL/6J-mice, representing the local character of lesion development in atherosclerosis.
Conclusion:
In the present work, we showed that k-t BLAST PC-MRI enables the measurement of the local PWV distribution in the mouse aorta. The semi-automatic segmentation method based on PC-CMR data allowed rapid determination of local PWV. The findings of this study demonstrate the ability of the proposed methods to non-invasively quantify the spatial variations in local PWV along the aorta of ApoE\(^{(-/-)}\)-mice as a relevant model of atherosclerosis.
Nonalcoholic fatty liver disease, induced by a Western diet (WD), evokes central and peripheral inflammation that is accompanied by altered emotionality. These changes can be associated with abnormalities in social behaviour, hippocampus-dependent cognitive functions, and metabolism. Female C57BL/6J mice were fed with a regular chow or with a WD containing 0.2% of cholesterol and 21% of saturated fat for three weeks. WD-treated mice exhibited increased social avoidance, crawl-over and digging behaviours, decreased body-body contacts, and hyperlocomotion. The WD-fed group also displayed deficits in hippocampal-dependent performance such as contextual memory in a fear conditioning and pellet displacement paradigms. A reduction in glucose tolerance and elevated levels of serum cholesterol and leptin were also associated with the WD. The peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1a) mRNA, a marker of mitochondrial activity, was decreased in the prefrontal cortex, hippocampus, hypothalamus, and dorsal raphe, suggesting suppressed brain mitochondrial functions, but not in the liver. This is the first report to show that a WD can profoundly suppress social interactions and induce dominant-like behaviours in naïve adult mice. The spectrum of behaviours that were found to be induced are reminiscent of symptoms associated with autism, and, if paralleled in humans, suggest that a WD might exacerbate autism spectrum disorder.
The thesis deals with the automated generation and efficient evaluation of scattering amplitudes in general relativistic quantum field theories at one-loop order in perturbation theory. At the
present time we lack signals beyond the Standard Model which, in the past, have guided the
high-energy physics community, and ultimately led to the discovery of new physics phenomena.
In the future, precision tests could acquire this guiding role by systematically probing the Standard Model and constraining Beyond the Standard Model theories. As current experimental
constraints strongly favour Standard Model-like theories, only small deviations with respect to the Standard Model are expected which need to be studied in detail. The required precision
demands one-loop corrections in all future analyses, ideally in a fully automated way, allowing
to test a variety of observables in different models and in an effective field theory approach.
In the process of achieving this goal we have developed an enhanced version of the tool
Recola and on this basis the generalization Recola2. These tools represent fully automated
tree- and one-loop-amplitude providers for the Standard Model, or in the case of Recola2
for general models. Concerning the algorithm, we use a purely numerical and fully recursive
approach allowing for extreme calculations of yet unmatched complexity. Recola has led to the first computation involving 9-point functions. Beyond the Standard Model theories and Effective Field theories are integrated into the Recola2 framework as model files. Renormalized model files are produced with the newly developed tool Rept1l, which can perform the renormalization in a fully automated way, starting from nothing but Feynman rules. In view of validation, we have extended Recola2 to new gauges such as the Background-Field Method and the class of Rxi gauges. In particular, the Background-Field Method formulation for new theories serves as an automated validation, and is very useful in practical calculations and the formulation of renormalization conditions. We have applied the system to produce the first results for Higgs-boson production in Higgs strahlung and vector-boson fusion in the Two-Higgs-Doublet Model and the Higgs-Singlet Extension of the Standard Model. All in all, we have laid the foundation for an automated generation and computation of one-loop amplitudes within a large class of phenomenologically interesting theories. Furthermore, we enable the use of our system via a very flexible and dynamic control which does not require any intermediate intervention.
This publication presents the combination of the one-loop matrix-element generator Recola with the multipurpose Monte Carlo program Sherpa. Since both programs are highly automated, the resulting Sherpa +Recola framework allows for the computation of – in principle – any Standard Model process at both NLO QCD and EW accuracy. To illustrate this, three representative LHC processes have been computed at NLO QCD and EW: vector-boson production in association with jets, off-shell Z-boson pair production, and the production of a top-quark pair in association with a Higgs boson. In addition to fixed-order computations, when considering QCD corrections, all functionalities of Sherpa, i.e. particle decays, QCD parton showers, hadronisation, underlying events, etc. can be used in combination with Recola. This is demonstrated by the merging and matching of one-loop QCD matrix elements for Drell–Yan production in association with jets to the parton shower. The implementation is fully automatised, thus making it a perfect tool for both experimentalists and theorists who want to use state-of-the-art predictions at NLO accuracy.
Plants initially accepted by foraging leaf-cutting ants are later avoided if they prove unsuitable for their symbiotic fungus. Plant avoidance is mediated by the waste produced in the fungus garden soon after the incorporation of the unsuitable leaves, as foragers can learn plant odors and cues from the damaged fungus that are both present in the recently produced waste particles. We asked whether avoidance learning of plants unsuitable for the symbiotic fungus can take place entirely at the colony dump. In order to investigate whether cues available in the waste chamber induce plant avoidance in naïve subcolonies, we exchanged the waste produced by subcolonies fed either fungicide-treated privet leaves or untreated leaves and measured the acceptance of untreated privet leaves before and after the exchange of waste. Second, we evaluated whether foragers could perceive the avoidance cues directly at the dump by quantifying the visits of labeled foragers to the waste chamber. Finally, we asked whether foragers learn to specifically avoid untreated leaves of a plant after a confinement over 3 hours in the dump of subcolonies that were previously fed fungicide-treated leaves of that species. After the exchange of the waste chambers, workers from subcolonies that had access to waste from fungicide-treated privet leaves learned to avoid that plant. One-third of the labeled foragers visited the dump. Furthermore, naïve foragers learned to avoid a specific, previously unsuitable plant if exposed solely to cues of the dump during confinement. We suggest that cues at the dump enable foragers to predict the unsuitable effects of plants even if they had never been experienced in the fungus garden.
Background
Lymphocytes have been shown to play an important role in the pathophysiology of acute ischemic stroke, but the properties of B cells remain controversial. The aim of this study was to unravel the role of B cells during acute cerebral ischemia using pharmacologic B cell depletion, B cell transgenic mice, and adoptive B cell transfer experiments.
Methods
Transient middle cerebral artery occlusion (60 min) was induced in wild-type mice treated with an anti-CD20 antibody 24 h before stroke onset, JHD\(^{−/−}\) mice and Rag1\(^{−/−}\) mice 24 h after adoptive B cell transfer. Stroke outcome was assessed at days 1 and 3. Infarct volumes were calculated from 2,3,5-triphenyltetrazolium chloride (TTC)-stained brain sections, and neurological scores were evaluated. The local inflammatory response was determined by real-time PCR and immunohistochemistry. Apoptosis was analyzed by TUNEL staining, and astrocyte activation was revealed using immunohistochemistry and Western blot.
Results
Pharmacologic depletion of B cells did not influence infarct volumes and functional outcome at day 1 after stroke. Additionally, lack of circulating B cells in JHD\(^{−/−}\) mice also failed to influence stroke outcome at days 1 and 3. Furthermore, reconstitution of Rag1\(^{−/−}\) mice with B cells had no influence on infarct volumes.
Conclusion
Targeting B cells in experimental stroke did not influence lesion volume and functional outcome during the acute phase. Our findings argue against a major pathophysiologic role of B cells during acute ischemic stroke.
Exciton-polaritons in semiconductor microcavities form a highly nonlinear platform to study a variety of effects interfacing optical, condensed matter, quantum and statistical physics. We show that the complex polariton patterns generated by picosecond pulses in microcavity wire waveguides can be understood as the Cherenkov radiation emitted by bright polariton solitons, which is enabled by the unique microcavity polariton dispersion, which has momentum intervals with positive and negative group velocities. Unlike in optical fibres and semiconductor waveguides, we observe that the microcavity wire Cherenkov radiation is predominantly emitted with negative group velocity and therefore propagates backwards relative to the propagation direction of the emitting soliton. We have developed a theory of the microcavity wire polariton solitons and of their Cherenkov radiation and conducted a series of experiments, where we have measured polariton-soliton pulse compression, pulse breaking and emission of the backward Cherenkov radiation.
Spontaneous Ca\(^{2+}\) transients and actin dynamics in primary motoneurons correspond to cellular differentiation such as axon elongation and growth cone formation. Brain-derived neurotrophic factor (BDNF) and its receptor trkB support both motoneuron survival and synaptic differentiation. However, in motoneurons effects of BDNF/trkB signaling on spontaneous Ca\(^{2+}\) influx and actin dynamics at axonal growth cones are not fully unraveled. In our study we addressed the question how neurotrophic factor signaling corresponds to cell autonomous excitability and growth cone formation. Primary motoneurons from mouse embryos were cultured on the synapse specific, β2-chain containing laminin isoform (221) regulating axon elongation through spontaneous Ca\(^{2+}\) transients that are in turn induced by enhanced clustering of N-type specific voltage-gated Ca\(^{2+}\) channels (Ca\(_{v}\)2.2) in axonal growth cones. TrkB-deficient (trkBTK\(^{-/-}\)) mouse motoneurons which express no full-length trkB receptor and wildtype motoneurons cultured without BDNF exhibited reduced spontaneous Ca\(^{2+}\) transients that corresponded to altered axon elongation and defects in growth cone morphology which was accompanied by changes in the local actin cytoskeleton. Vice versa, the acute application of BDNF resulted in the induction of spontaneous Ca\(^{2+}\) transients and Ca\(_{v}\)2.2 clustering in motor growth cones, as well as the activation of trkB downstream signaling cascades which promoted the stabilization of β-actin via the LIM kinase pathway and phosphorylation of profilin at Tyr129. Finally, we identified a mutual regulation of neuronal excitability and actin dynamics in axonal growth cones of embryonic motoneurons cultured on laminin-221/211. Impaired excitability resulted in dysregulated axon extension and local actin cytoskeleton, whereas upon β-actin knockdown Ca\(_{v}\)2.2 clustering was affected. We conclude from our data that in embryonic motoneurons BDNF/trkB signaling contributes to axon elongation and growth cone formation through changes in the local actin cytoskeleton accompanied by increased Ca\(_{v}\)2.2 clustering and local calcium transients. These findings may help to explore cellular mechanisms which might be dysregulated during maturation of embryonic motoneurons leading to motoneuron disease.
Becker naevus syndrome is a rare epidermal naevus syndrome defined by the co-occurrence of a Becker naevus with various cutaneous, muscular and skeletal anomalies. In the majority of cases, abnormalities exclusively consist of ipsilateral hypoplasia of the breast, areola and/or nipple in addition to the naevus. Here, we report on a 42-year-old woman with an extensive Becker naevus reaching from the left buttock to the left calf verified on histological examination. In addition, there was marked hypoplasia of the fatty tissue of the left thigh confirmed by magnetic resonance imaging in contrast to hyperplasia of the fatty tissue of the left gluteal area. Underlying muscles and bones were not affected. There was no difference in leg lengths. In addition, we review and discuss the features of Becker naevus syndrome with emphasis on 10 reported cases with involvement of the lower body.
Bee pollination increases yield quantity and quality of cash crops in Burkina Faso, West Africa
(2017)
Mutualistic biotic interactions as among flowering plants and their animal pollinators are a key component of biodiversity. Pollination, especially by insects, is a key element in ecosystem functioning, and hence constitutes an ecosystem service of global importance. Not only sexual reproduction of plants is ensured, but also yields are stabilized and genetic variability of crops is maintained, counteracting inbreeding depression and facilitating system resilience. While experiencing rapid environmental change, there is an increased demand for food and income security, especially in sub-Saharan communities, which are highly dependent on small scale agriculture. By combining exclusion experiments, pollinator surveys and field manipulations, this study for the first time quantifies the contribution of bee pollinators to smallholders’ production of the major cash crops, cotton and sesame, in Burkina Faso. Pollination by honeybees and wild bees significantly increased yield quantity and quality on average up to 62%, while exclusion of pollinators caused an average yield gap of 37% in cotton and 59% in sesame. Self-pollination revealed inbreeding depression effects on fruit set and low germination rates in the F1-generation. Our results highlight potential negative consequences of any pollinator decline, provoking risks to agriculture and compromising crop yields in sub-Saharan West Africa.
A fundamental problem in deciding between mutually exclusive options is that the decision needs to be categorical although the properties of the options often differ but in grade. We developed an experimental handle to study this aspect of behavior organization. Larval Drosophila were trained such that in one set of animals odor A was rewarded, but odor B was not (A+/B), whereas a second set of animals was trained reciprocally (A/B+). We then measured the preference of the larvae either for A, or for B, or for “morphed” mixtures of A and B, that is for mixtures differing in the ratio of the two components. As expected, the larvae showed higher preference when only the previously rewarded odor was presented than when only the previously unrewarded odor was presented. For mixtures of A and B that differed in the ratio of the two components, the major component dominated preference behavior—but it dominated less than expected from a linear relationship between mixture ratio and preference behavior. This suggests that a minor component can have an enhanced impact in a mixture, relative to such a linear expectation. The current paradigm may prove useful in understanding how nervous systems generate discrete outputs in the face of inputs that differ only gradually.
Multiple sclerosis (MS) is the most prevalent neurological disease of the central nervous system (CNS) in young adults and is characterized by inflammation, demyelination and axonal pathology that result in multiple neurological and cognitive deficits. The focus of MS research remains on modulating the immune response, but common therapeutic strategies are only effective in slowing down disease progression and attenuating the symptoms; they cannot cure the disease. Developing an option to prevent neurodegeneration early on would be a valuable addition to the current standard of care for MS. Based on our results we suggest that application of nimodipine could be an effective way to target both neuroinflammation and neurodegeneration. We performed detailed analyses of neurodegeneration in experimental autoimmune encephalomyelitis (EAE), an animal model of MS, and in in vitro experiments regarding the effect of the clinically well-established L-type calcium channel antagonist nimodipine. Nimodipine treatment attenuated the course of EAE and spinal cord histopathology. Furthermore, it promoted remyelination. The latter could be due to the protective effect on oligodendrocytes and oligodendrocyte precursor cells (OPCs) we observed in response to nimodipine treatment. To our surprise, we detected calcium channel-independent effects on microglia, resulting in apoptosis. These effects were cell type-specific and independent of microglia polarization. Apoptosis was accompanied by decreased levels of nitric oxide (NO) and inducible NO synthase (iNOS) in cell culture as well as decreased iNOS expression and reactive oxygen species (ROS) activity in EAE. Overall, application of nimodipine seems to generate a favorable environment for regenerative processes and could therefore be a novel treatment option for MS, combining immunomodulatory effects while promoting neuroregeneration.
Beyond maximum independent set: an extended integer programming formulation for point labeling
(2017)
Map labeling is a classical problem of cartography that has frequently been approached by combinatorial optimization. Given a set of features in a map and for each feature a set of label candidates, a common problem is to select an independent set of labels (that is, a labeling without label–label intersections) that contains as many labels as possible and at most one label for each feature. To obtain solutions of high cartographic quality, the labels can be weighted and one can maximize the total weight (rather than the number) of the selected labels. We argue, however, that when maximizing the weight of the labeling, the influences of labels on other labels are insufficiently addressed. Furthermore, in a maximum-weight labeling, the labels tend to be densely packed and thus the map background can be occluded too much. We propose extensions of an existing model to overcome these limitations. Since even without our extensions the problem is NP-hard, we cannot hope for an efficient exact algorithm for the problem. Therefore, we present a formalization of our model as an integer linear program (ILP). This allows us to compute optimal solutions in reasonable time, which we demonstrate both for randomly generated point sets and an existing data set of cities. Moreover, a relaxation of our ILP allows for a simple and efficient heuristic, which yielded near-optimal solutions for our instances.
RNA-binding proteins (RBPs) have been extensively studied in eukaryotes, where they post-transcriptionally regulate many cellular events including RNA transport, translation, and stability. Experimental techniques, such as cross-linking and co-purification followed by either mass spectrometry or RNA sequencing has enabled the identification and characterization of RBPs, their conserved RNA-binding domains (RBDs), and the regulatory roles of these proteins on a genome-wide scale. These developments in quantitative, high-resolution, and high-throughput screening techniques have greatly expanded our understanding of RBPs in human and yeast cells. In contrast, our knowledge of number and potential diversity of RBPs in bacteria is comparatively poor, in part due to the technical challenges associated with existing global screening approaches developed in eukaryotes.
Genome- and proteome-wide screening approaches performed in silico may circumvent these technical issues to obtain a broad picture of the RNA interactome of bacteria and identify strong RBP candidates for more detailed experimental study. Here, I report APRICOT (“Analyzing Protein RNA Interaction by Combined Output Technique”), a computational pipeline for the sequence-based identification and characterization of candidate RNA-binding proteins encoded in the genomes of all domains of life using RBDs known from experimental studies. The pipeline identifies functional motifs in protein sequences of an input proteome using position-specific scoring matrices and hidden Markov models of all conserved domains available in the databases and then statistically score them based on a series of sequence-based features. Subsequently, APRICOT identifies putative RBPs and characterizes them according to functionally relevant structural properties. APRICOT performed better than other existing tools for the sequence-based prediction on the known RBP data sets. The applications and adaptability of the software was demonstrated on several large bacterial RBP data sets including the complete proteome of Salmonella Typhimurium strain SL1344. APRICOT reported 1068 Salmonella proteins as RBP candidates, which were subsequently categorized using the RBDs that have been reported in both eukaryotic and bacterial proteins. A set of 131 strong RBP candidates was selected for experimental confirmation and characterization of RNA-binding activity using RNA co-immunoprecipitation followed by high-throughput sequencing (RIP-Seq) experiments. Based on the relative abundance of transcripts across the RIP-Seq libraries, a catalogue of enriched genes was established for each candidate, which shows the RNA-binding potential of 90% of these proteins. Furthermore, the direct targets of few of these putative RBPs were validated by means of cross-linking and co-immunoprecipitation (CLIP) experiments.
This thesis presents the computational pipeline APRICOT for the global screening of protein primary sequences for potential RBPs in bacteria using RBD information from all kingdoms of life. Furthermore, it provides the first bio-computational resource of putative RBPs in Salmonella, which could now be further studied for their biological and regulatory roles. The command line tool and its documentation are available at https://malvikasharan.github.io/APRICOT/.
Marine sponges are known as a rich source for novel bioactive compounds with valuable pharmacological potential. One of the most predominant sponge genera is Hyrtios, reported to have various species such as Hyrtios erectus, Hyrtios reticulatus, Hyrtios gumminae, Hyrtios communis, and Hyrtios tubulatus and a number of undescribed species. Members of the genus Hyrtios are a rich source of natural products with diverse and valuable biological activities, represented by different chemical classes including alkaloids, sesterterpenes and sesquiterpenes. This review covers the literature until June 2016, providing a complete survey of all compounds isolated from the genus Hyrtios with their corresponding biological activities whenever applicable.
Background:
Bone-ligament-bone grafts for reconstruction of the scapholunate ligament are a valuable tool to prevent disease progression to carpal collapse. Locally available grafts do not require an additional donor site. The first extensor compartment was evaluated biomechanically regarding its possible use as an autograft.
Methods:
Twelve native fresh-frozen, human cadaver specimens were tested by applying axial tension in a Zwick Roell machine. Load to failure, transplant elongation, and bony avulsion were recorded. The load to failure was quantitated in newtons (N) and the displacement in length (millimeters). Parameters were set at distinct points as start of tension, 1 mm stretch and 1.5 mm dissociation, failure and complete tear, and were evaluated under magnified visual control. Although actual failure occurred at higher tension, functional failure was defined at a stretch of 1.5 mm.
Results:
Mean load at 1 mm elongation was 44.1 ± 28 N and at 1.5 mm elongation 57.5 ± 42 N. Failure occurred at 111 ± 83.1 N. No avulsion of the bony insertion was observed. Half the transplants failed in the central part of the ligament, while the rest failed near the insertion but not at the insertion itself. Analysis of tension strength displayed a wide range from 3.8 to 83.7 N/mm at a mean of 33.4 ± 28.4 N/mm.
Conclusions:
The biomechanical tensile properties of the first dorsal extensor compartment are similar to those of the dorsal part of the scapholunate ligament. A transplant with a larger bone stock and a longer ligament may display an advantage, as insertion is possible in the dorsal, easily accessible part of the carpal bones rather than in the arête-like region adjacent to the insertion of the scapholunate ligament. In this study, 1.5 mm lengthening of the bone–ligament–bone transplant was defined as clinical failure, as such elongation will cause severe gapping and is considered as failure of the transplant.
Background:
Ischemic stroke causes a strong inflammatory response that includes T cells, monocytes/macrophages, and neutrophils. Interaction of these immune cells with platelets and endothelial cells facilitates microvascular dysfunction and leads to secondary infarct growth. We recently showed that blocking of platelet glycoprotein (GP) receptor Ib improves stroke outcome without increasing the risk of intracerebral hemorrhage. Until now, it has been unclear whether GPIb only mediates thrombus formation or also contributes to the pathophysiology of local inflammation.
Methods:
Focal cerebral ischemia was induced in C57BL/6 mice by a 60-min transient middle cerebral artery occlusion (tMCAO). Animals were treated with antigen-binding fragments (Fab) against the platelet surface molecules GPIb (p0p/B Fab). Rat immunoglobulin G (IgG) Fab was used as control treatment. Stroke outcome, including infarct size and functional deficits as well as the local inflammatory response, was assessed on day 1 after tMCAO.
Results:
Blocking of GPIb reduced stroke size and improved functional outcome on day 1 after tMCAO without increasing the risk of intracerebral hemorrhage. As expected, disruption of GPIb-mediated pathways in platelets significantly reduced thrombus burden in the cerebral microvasculature. In addition, inhibition of GPIb limited the local inflammatory response in the ischemic brain as indicated by lower numbers of infiltrating T cells and macrophages and lower expression levels of inflammatory cytokines compared with rat IgG Fab-treated controls.
Conclusion:
In acute ischemic stroke, thrombus formation and inflammation are closely intertwined (“thrombo-inflammation”). Blocking of platelet GPIb can ameliorate thrombo-inflammation.
The potassium salt of the boron-centred nucleophile B(CN)\(_{3}\)\(^{2-}\)(1) readily reacts with perfluorinated arenes, such as hexafluorobenzene, decafluorobiphenyl, octafluoronaphthalene and pentafluoropyridine, which results in KF and the K\(^{+}\) salts of the respective borate anions with one {B(CN)\(_{3}\)} unit bonded to the (hetero)arene. An excess of K\(_{2}\)1 leads to the successive reaction of two or, in the case of perfluoropyridine, even three C–F moieties and the formation of di- and trianions, respectively. Moreover, all of the 11 partially fluorinated benzene derivatives, C\(_{6}\)F\(_{6-n}\)H\(_{n}\) (n = 1–5), generally react with K\(_{2}\)1 to give new tricyano(phenyl)borate anions with high chemo- and regioselectivity. A decreasing number of fluorine substituents on benzene results in a decrease in the reaction rate. In the cases of partially fluorinated benzenes, the addition of LiCl is advantageous or even necessary to facilitate the reaction. Also, pentafluorobenzenes R–C\(_{6}\)F\(_{5}\) (R = –CN, –OMe, –Me, or –CF\(_{3}\)) react via C–F/C–B exchange that mostly occurs in the para position and to a lesser extent in the meta or ortho positions. Most of the reactions proceed via an S\(_{N}\)Ar mechanism. The reaction of 1,4-F\(_{2}\)C\(_{6}\)H\(_{4}\) with K\(_{2}\)1 shows that an aryne mechanism has to be considered in some cases as well. In summary, a wealth of new stable tricyano(aryl)borates have been synthesised and fully characterized using multi-NMR spectroscopy and most of them were characterised using single-crystal X-ray diffraction.
Background: During early prenatal stages of brain development, serotonin (5-HT)-specific neurons migrate through somal translocation to form the raphe nuclei and subsequently begin to project to their target regions. The rostral cluster of cells, comprising the median and dorsal raphe (DR), innervates anterior regions of the brain, including the prefrontal cortex. Differential analysis of the mouse 5-HT system transcriptome identified enrichment of cell adhesion molecules in 5-HT neurons of the DR. One of these molecules, cadherin-13 (Cdh13) has been shown to play a role in cell migration, axon pathfinding, and synaptogenesis. This study aimed to investigate the contribution of Cdh13 to the development of the murine brain 5-HT system.
Methods: For detection of Cdh13 and components of the 5-HT system at different embryonic developmental stages of the mouse brain, we employed immunofluorescence protocols and imaging techniques, including epifluorescence, confocal and structured illumination microscopy. The consequence of CDH13 loss-of-function mutations on brain 5-HT system development was explored in a mouse model of Cdh13 deficiency.
Results: Our data show that in murine embryonic brain Cdh13 is strongly expressed on 5-HT specific neurons of the DR and in radial glial cells (RGCs), which are critically involved in regulation of neuronal migration. We observed that 5-HT neurons are intertwined with these RGCs, suggesting that these neurons undergo RGC-guided migration. Cdh13 is present at points of intersection between these two cell types. Compared to wildtype controls, Cdh13-deficient mice display increased cell densities in the DR at embryonic stages E13.5, E17.5, and adulthood, and higher serotonergic innervation of the prefrontal cortex at E17.5.
Conclusion: Our findings provide evidence for a role of CDH13 in the development of the serotonergic system in early embryonic stages. Specifically, we indicate that Cdh13 deficiency affects the cell density of the developing DR and the posterior innervation of the prefrontal cortex (PFC), and therefore might be involved in the migration, axonal outgrowth and terminal target finding of DR 5-HT neurons. Dysregulation of CDH13 expression may thus contribute to alterations in this system of neurotransmission, impacting cognitive function, which is frequently impaired in neurodevelopmental disorders including attention-deficit/hyperactivity and autism spectrum disorders.
Background:
Although caffeine and glucocorticoids are frequently used to treat chronic lung disease in preterm neonates, potential interactions are largely unknown. While anti-inflammatory effects of glucocorticoids are well defined, their impact on airway remodeling is less characterized. Caffeine has been ascribed to positive effects on airway inflammation as well as remodeling. Connective tissue growth factor (CTGF, CCN2) plays a key role in airway remodeling and has been implicated in the pathogenesis of chronic lung diseases such as bronchopulmonary dysplasia (BPD) in preterm infants. The current study addressed the impact of glucocorticoids on the regulation of CTGF in the presence of caffeine using human lung epithelial and fibroblast cells.
Methods:
The human airway epithelial cell line H441 and the fetal lung fibroblast strain IMR-90 were exposed to different glucocorticoids (dexamethasone, budesonide, betamethasone, prednisolone, hydrocortisone) and caffeine. mRNA and protein expression of CTGF, TGF-β1-3, and TNF-α were determined by means of quantitative real-time PCR and immunoblotting. H441 cells were additionally treated with cAMP, the adenylyl cyclase activator forskolin, and the selective phosphodiesterase (PDE)-4 inhibitor cilomilast to mimic caffeine-mediated PDE inhibition.
Results:
Treatment with different glucocorticoids (1 μM) significantly increased CTGF mRNA levels in H441 (p < 0.0001) and IMR-90 cells (p < 0.01). Upon simultaneous exposure to caffeine (10 mM), both glucocorticoid-induced mRNA and protein expression were significantly reduced in IMR-90 cells (p < 0.0001). Of note, 24 h exposure to caffeine alone significantly suppressed basal expression of CTGF mRNA and protein in IMR-90 cells. Caffeine-induced reduction of CTGF mRNA expression seemed to be independent of cAMP levels, adenylyl cyclase activation, or PDE-4 inhibition. While dexamethasone or caffeine treatment did not affect TGF-β1 mRNA in H441 cells, increased expression of TGF-β2 and TGF-β3 mRNA was detected upon exposure to dexamethasone or dexamethasone and caffeine, respectively. Moreover, caffeine increased TNF-α mRNA in H441 cells (6.5 ± 2.2-fold, p < 0.05) which has been described as potent inhibitor of CTGF expression.
Conclusions:
In addition to well-known anti-inflammatory features, glucocorticoids may have adverse effects on long-term remodeling by TGF-β1-independent induction of CTGF in lung cells. Simultaneous treatment with caffeine may attenuate glucocorticoid-induced expression of CTGF, thereby promoting restoration of lung homeostasis.
New multifunctional nanoparticles (NPs) that can be used as contrast agents (CA) in different imaging techniques, such as photoluminescence (PL) microscopy and magnetic resonance imaging (MRI), open new possibilities for medical imaging, e.g., in the fields of diagnostics or tissue characterization in regenerative medicine. The focus of this study is on the synthesis and characterization of CaF\(_{2}\):(Tb\(^{3+}\),Gd\(^{3+}\)) NPs. Fabricated in a wet-chemical procedure, the spherical NPs with a diameter of 5–10 nm show a crystalline structure. Simultaneous doping of the NPs with different lanthanide ions, leading to paramagnetism and fluorescence, makes them suitable for MR and PL imaging. Owing to the Gd\(^{3+}\) ions on the surface, the NPs reduce the MR T\(_{1}\) relaxation time constant as a function of their concentration. Thus, the NPs can be used as a MRI CA with a mean relaxivity of about r = 0.471 mL·mg\(^{−1}\)·s\(^{−1}\). Repeated MRI examinations of four different batches prove the reproducibility of the NP synthesis and determine the long-term stability of the CAs. No cytotoxicity of NP concentrations between 0.5 and 1 mg·mL\(^{−1}\) was observed after exposure to human dermal fibroblasts over 24 h. Overall this study shows, that the CaF\(_{2}\):(Tb\(^{3+}\),Gd\(^{3+}\)) NPs are suitable for medical imaging.
The dissertation aims at investigating how information about jobs arriving to a service facility in the future can be used for capacity planning and control. Nowadays, technical equipment such as aircraft engines are equipped with sensors transferring condition data to central data warehouses in real-time. By jointly analyzing condition data and future usage information with machine learning algorithms, future equipment conditions and maintenance requirements can be forecasted. In the thesis, information regarding the arrival times of aircraft engine at a maintenance facility and the corresponding service requirements are used in order to optimally plan and control the flexible capacity of the facility. Queueing models are developed and analyzed to optimally size and control the facility's capacity and determine the implications on cost and job waiting time. It is demonstrated analytically and numerically that cost and waiting time can be reduced significantly when future information is available.
Defense against biotic or abiotic stresses is one of the benefits of living in symbiosis. Leaf-cutting ants, which live in an obligate mutualism with a fungus, attenuate thermal and desiccation stress of their partner through behavioral responses, by choosing suitable places for fungus-rearing across the soil profile. The underground environment also presents hypoxic (low oxygen) and hypercapnic (high carbon dioxide) conditions, which can negatively influence the symbiont. Here, we investigated whether workers of the leaf-cutting ant Acromyrmex lundii use the CO\(_{2}\) concentration as an orientation cue when selecting a place to locate their fungus garden, and whether they show preferences for specific CO\(_{2}\) concentrations. We also evaluated whether levels preferred by workers for fungus-rearing differ from those selected for themselves. In the laboratory, CO\(_{2}\) preferences were assessed in binary choices between chambers with different CO\(_{2}\) concentrations, by quantifying number of workers in each chamber and amount of relocated fungus. Leaf-cutting ants used the CO\(_{2}\) concentration as a spatial cue when selecting places for fungus-rearing. A. lundii preferred intermediate CO\(_{2}\) levels, between 1 and 3%, as they would encounter at soil depths where their nest chambers are located. In addition, workers avoided both atmospheric and high CO\(_{2}\) levels as they would occur outside the nest and at deeper soil layers, respectively. In order to prevent fungus desiccation, however, workers relocated fungus to high CO\(_{2}\) levels, which were otherwise avoided. Workers’ CO\(_{2}\) preferences for themselves showed no clear-cut pattern. We suggest that workers avoid both atmospheric and high CO\(_{2}\) concentrations not because they are detrimental for themselves, but because of their consequences for the symbiotic partner. Whether the preferred CO\(_{2}\) concentrations are beneficial for symbiont growth remains to be investigated, as well as whether the observed preferences for fungus-rearing influences the ants’ decisions where to excavate new chambers across the soil profile.
Background
Aortic valve stenosis is a common finding diagnosed with high sensitivity in transthoracic echocardiography, but the examiner often finds himself confronted with uncertain results in patients with moderate pressure gradients and concomitant systolic heart failure. While patients with true-severe low-gradient aortic valve stenosis with either reduced or preserved left ventricular systolic function are primarily candidates for valve replacement, there is a relevant proportion of patients with pseudo-severe aortic valve stenosis anticipated not to benefit but actually rather deteriorate by interventional therapy or surgery.
Case presentation
In this article we present a case report of a male patient with pseudo-severe aortic valve stenosis due to cardiac amyloidosis highlighting the diagnostic schedule. The patient underwent stress echocardiography because of discrepant findings in transthoracic echocardiography and cardiac catheterization regarding the severity of aortic valve stenosis. After evaluation of the results, it became clear that he had a need for optimum heart failure medication and implantation of a cardiac resynchronization therapy defibrillator.
Conclusion
Due to the pitfalls in conventional as well as invasive diagnostics at rest, Stress echocardiography should be considered part of the standard optimum diagnostic spectrum in all unclear or borderline cases in order to confirm the correct diagnosis and constitute optimal therapy.
Background
Fabry disease (FD) is an X-linked recessive hereditary lysosomal storage disorder which results in the accumulation of globotriaosylceramid (Gb3) in tissues of kidney and heart as well as central and peripheral nervous system.
Besides prominent renal and cardiac organ involvement, cochlear symptoms like high-frequency hearing loss and tinnitus are frequently found with yet no comprehensive data available in the literature.
Objective
To examine hearing loss in patients with FD depending on cardiac and renal function.
Material and methods
Single-center study with 68 FD patients enrolled between 2012 and 2016 at the Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery of the University of Würzburg. Every subject underwent an oto-rhino-laryngological examination as well as behavioral, electrophysiological and electroacoustical audiological testing. High-frequency thresholds were evaluated by using a modified PTA\(_{6}\) (0.5, 1, 2, 4, 6, 8) and HF-PTA (6, 8 kHz). Renal function was measured by eGFR, cardiac impairment was graduated by NYHA class.
Results
Sensorineural hearing loss was detected in 58.8% of the cohort, which occurred typically in sudden episodes and affected especially high frequencies. Hearing loss is asymmetric, beginning unilaterally and affecting the contralateral ear later. Tinnitus was reported by 41.2%. Renal and cardiac impairment influenced the severity of hearing loss (p < 0.05).
Conclusions
High frequency hearing loss is a common problem in patients with FD. Although not life-threatening, it can seriously reduce quality of life and should be taken into account in diagnosis and therapy. Optimized extensive hearing assessment including higher frequency thresholds should be used.
This dissertation contributes to deepen our understanding of constructs that play a key role in individuals’ vocational career construction. In this regard, many previous studies have focused exclusively on a specific phase of an individual’s career. Yet, modern societies
require continuous investments in one’s career to adapt to changing Environments throughout the life span. Consequently, this dissertation takes a broad approach to capture a wide spectrum of career construction processes.
According to Super’s (1990) developmental stage framework, individuals have to manage vocational developmental tasks corresponding to each of the developmental life stages in order to be career mature across the life span. As the two stages exploration and
maintenance set the stage for individuals’ future career pathways, they are especially important in individuals’ vocational career construction. Therefore, both of them are addressed in this dissertation.
By answering open research questions relevant to career choice in early career stages and to career development in later career stages, this dissertation contributes to the overarching goal of shedding more light on constructs relevant to individuals’ vocational career construction processes across the life span. Beyond the results presented within each study’s horizon, this dissertation aimed at offering practical guidance to career counselors,
trainees, and training and development (T&D) professionals. Career counselors and T&D professionals are involved in guiding vocational career construction processes of individuals across the life span. Thus, on the one hand, this dissertation supports career counselors’ work so that they can help deliberating individuals make optimal and effective career choices. On
the other hand, this dissertation facilitates T&D professionals’ work so that they can effectively design and evaluate e‐learning and classroom trainings in corporate educational settings. Identifying individuals’ vocational interests combined with cognitive abilities through adequate test measures and maximizing success of learning and success of transfer through fostering evidence‐based transfer support actions will help individuals adapt quickly to the changing nature of work environments in the 21st century and to continue to successfully construct careers across the life span.
We have investigated optical properties of hybrid two-dimensional-zero-dimensional (2D-0D) tunnel structures containing strongly elongated InAs/InP(001) quantum dots (called quantum dashes), emitting at 1.55 μm. These quantum dashes (QDashes) are separated by a 2.3 nm-width barrier from an InGaAs quantum well (QW), lattice matched to InP. We have tailored quantum-mechanical coupling between the states confined in QDashes and a QW by changing the QW thickness. By combining modulation spectroscopy and photoluminescence excitation, we have determined the energies of all relevant optical transitions in the system and proven the carrier transfer from the QW to the QDashes, which is the fundamental requirement for the tunnel injection scheme. A transformation between 0D and mixed-type 2D-0D character of an electron and a hole confinement in the ground state of the hybrid system have been probed by time-resolved photoluminescence that revealed considerable changes in PL decay time with the QW width changes. The experimental discoveries have been explained by band structure calculations in the framework of the eight-band k·p model showing that they are driven by delocalization of the lowest energy hole state. The hole delocalization process from the 0D QDash confinement is unfavorable for optical devices based on such tunnel injection structures.
Background:
Clinical reasoning in Neurology is based on general associations which help to deduce the site of the lesion. However, even “golden principles” may occasionally be deceptive. Here, we describe the case of subacute flaccid tetraparesis due to motor cortical lesions. To our knowledge, this is the first report to include an impressive illustration of nearly symmetric motor cortical involvement of encephalitis on brain MRI.
Case presentation:
A 51 year old immunocompromized man developed a high-grade pure motor flaccid tetraparesis over few days. Based on clinical presentation, critical illness polyneuromyopathy was suspected. However, brain MRI revealed symmetrical hyperintensities strictly limited to the subcortical precentral gyrus. An encephalitis, possibly due to CMV infection, turned out to be the most likely cause.
Conclusion:
While recognition of basic clinical patterns is indispensable in neurological reasoning, awareness of central conditions mimicking peripheral nervous disease may be crucial to detect unsuspected, potentially treatable conditions.
This dissertation investigates selected causes and effects of worker mobility between firms in three empirical studies for Germany. Chapter 2 investigates the productivity effects of worker inflows to manufacturing establishments, distinguishing inflows by their previous employers’ wage level, as a proxy for productivity. The chapter is motivated by several empirical studies which find that worker inflows from more productive or higher-paying firms increase hiring firms’ productivity. The analyses in chapter 2 are based on a unique linked employer-employee data set. The findings indicate that inflows from higher-paying establishments do not increase hiring establishments’ productivity, but inflows from lower-paying establishments do. Further analyses suggest that this effect is due to a positive selectivity of such inflows from their sending establishments. These findings can be interpreted as evidence of a reallocation process by which the best employees of lower-paying establishments become hired by higher-paying establishments. This process reflects the assortative pattern of worker mobility in Germany documented by Card et al. (2013) for the past decades. The chapter thus contributes to the literature by linking establishment-level productivity analysis to the assortative pattern of inter-firm worker mobility, thereby providing a micro-foundation for the latter.
Chapter 3 focuses on a positive selection of workers moving between firms from another, more specific perspective. The analysis focuses on the importance of regional labor market competition for establishments’ apprentice training and poaching of apprenticeship completers. Previous studies have found that firms provide less training if they are located in regions with strong labor market competition. This finding is usually interpreted as evidence of a higher risk of poaching in these regions. Yet, there is no direct evidence that regional competition is positively correlated with poaching. Building on a recently established approach to ex-post identify poaching of apprenticeship completers, this chapter is the first to directly investigate the correlation between regional labor market competition and poaching. Using German administrative data, it is found that competition indeed increases training establishments’ probability of becoming poaching victims. However, poaching victims do not change their apprenticeship training activity in reaction to poaching. Instead, the findings indicate that the lower training activity in competitive regions can be attributed to lower retention rates, as well as a less adverse selection and lower labor and hiring costs of apprenticeship completers hired from rivals.
Chapter 4 investigates the effects of local broadband internet availability on establishment-level employment growth. The analysis uses data for Germany in the years 2005-2009, when broadband was introduced in rural regions of Western Germany and in large parts of Eastern Germany. Technical frictions in broadband rollout are exploited to obtain exogenous variation in local broadband availability. The results suggest that broadband expansion had a positive effect on employment growth in the Western German service sector and a negative effect in Western German manufacturing, suggesting that broadband expansion has accelerated the reallocation of workers from manufacturing to services. Furthermore, this pattern of results is driven by pronounced positive effects in knowledge- and computer-intensive industries, suggesting that it is the actual use of broadband in the production process that leads to complementary hiring, respectively a slowdown of employment growth, in the respective sectors. For Eastern Germany, no significant employment growth effects are found.
Radiationless energy transfer is at the core of diverse phenomena, such as light harvesting in photosynthesis\(^1\), energy-transfer-based microspectroscopies\(^2\), nanoscale quantum entanglement\(^3\) and photonic-mode hybridization\(^4\). Typically, the transfer is efficient only for separations that are much shorter than the diffraction limit. This hampers its application in optical communication and quantum information processing, which require spatially selective addressing. Here, we demonstrate highly efficient radiationless coherent energy transfer over a distance of twice the excitation wavelength by combining localized and delocalized\(^5\) plasmonic modes. Analogous to the Tavis-Cummings model, two whispering-gallery-mode antennas\(^6\) placed in the foci of an elliptical plasmonic cavity\(^7\) fabricated from single-crystal gold plates act as a pair of oscillators coupled to a common cavity mode. Time-resolved two-photon photoemission electron microscopy (TR 2P-PEEM) reveals an ultrafast long-range periodic energy transfer in accordance with the simulations. Our observations open perspectives for the optimization and tailoring of mesoscopic energy transfer and long-range quantum emitter coupling.
Aspergillus (A.) fumigatus is an opportunistic fungal mold inducing invasive aspergillosis (IA) in immunocompromised patients. Although antifungal activity of human natural killer (NK) cells was shown in previous studies, the underlying cellular mechanisms and pathogen recognition receptors (PRRs) are still unknown. Using flow cytometry we were able to show that the fluorescence positivity of the surface receptor CD56 significantly decreased upon fungal contact. To visualize the interaction site of NK cells and A. fumigatus we used SEM, CLSM and dSTORM techniques, which clearly demonstrated that NK cells directly interact with A. fumigatus via CD56 and that CD56 is re-organized and accumulated at this interaction site time-dependently. The inhibition of the cytoskeleton showed that the receptor re-organization was an active process dependent on actin re-arrangements. Furthermore, we could show that CD56 plays a role in the fungus mediated NK cell activation, since blocking of CD56 surface receptor reduced fungal mediated NK cell activation and reduced cytokine secretion. These results confirmed the direct interaction of NK cells and A. fumigatus, leading to the conclusion that CD56 is a pathogen recognition receptor. These findings give new insights into the functional role of CD56 in the pathogen recognition during the innate immune response.
A central question to biology is how pathogenic bacteria initiate acute or chronic infections. Here we describe a genetic program for cell-fate decision in the opportunistic human pathogen Staphylococcus aureus, which generates the phenotypic bifurcation of the cells into two genetically identical but different cell types during the course of an infection. Whereas one cell type promotes the formation of biofilms that contribute to chronic infections, the second type is planktonic and produces the toxins that contribute to acute bacteremia. We identified a bimodal switch in the agr quorum sensing system that antagonistically regulates the differentiation of these two physiologically distinct cell types. We found that extracellular signals affect the behavior of the agr bimodal switch and modify the size of the specialized subpopulations in specific colonization niches. For instance, magnesium-enriched colonization niches causes magnesium binding to S. aureusteichoic acids and increases bacterial cell wall rigidity. This signal triggers a genetic program that ultimately downregulates the agr bimodal switch. Colonization niches with different magnesium concentrations influence the bimodal system activity, which defines a distinct ratio between these subpopulations; this in turn leads to distinct infection outcomes in vitro and in an in vivo murine infection model. Cell differentiation generates physiological heterogeneity in clonal bacterial infections and helps to determine the distinct infection types.
Background:
The standardized maritime pine bark extract (Pycnogenol\(^{®}\)) has previously shown symptom alleviating effects in patients suffering from moderate forms of knee osteoarthritis (OA). The cellular mechanisms for this positive impact are so far unknown. The purpose of the present randomized pilot controlled study was to span the knowledge gap between the reported clinical effects of Pycnogenol\(^{®}\) and its in vivo mechanism of action in OA patients.
Methods:
Thirty three patients with severe OA scheduled for a knee arthroplasty either received 100 mg of Pycnogenol\(^{®}\) twice daily or no treatment (control group) three weeks before surgery. Cartilage, synovial fluid and serum samples were collected during surgical intervention. Relative gene expression of cartilage homeostasis markers were analyzed in the patients' chondrocytes. Inflammatory and cartilage metabolism mediators were investigated in serum and synovial fluid samples.
Results:
The oral intake of Pycnogenol\(^{®}\) downregulated the gene expression of various cartilage degradation markers in the patients' chondrocytes, the decrease of MMP3, MMP13 and the pro-inflammatory cytokine IL1B were statistically significant (p ≤ 0.05). Additionally, protein concentrations of ADAMTS-5 in serum were reduced significantly (p ≤ 0.05) after three weeks intake of the pine bark extract.
Conclusions:
This is the first report about positive cellular effects of a dietary supplement on key catabolic and inflammatory markers in patients with severe OA. The results provide a rational basis for understanding previously reported clinical effects of Pycnogenol\(^{®}\) on symptom scores of patients suffering from OA.
Animal circadian clocks consist of central and peripheral pacemakers, which are coordinated to produce daily rhythms in physiology and behaviour. Despite its importance for optimal performance and health, the mechanism of clock coordination is poorly understood. Here we dissect the pathway through which the circadian clock of Drosophila imposes daily rhythmicity to the pattern of adult emergence. Rhythmicity depends on the coupling between the brain clock and a peripheral clock in the prothoracic gland (PG), which produces the steroid hormone, ecdysone. Time information from the central clock is transmitted via the neuropeptide, sNPF, to non-clock neurons that produce the neuropeptide, PTTH. These secretory neurons then forward time information to the PG clock. We also show that the central clock exerts a dominant role on the peripheral clock. This use of two coupled clocks could serve as a paradigm to understand how daily steroid hormone rhythms are generated in animals.
The MuvB multiprotein complex, together with B-MYB and FOXM1 (MMB-FOXM1), plays an essential role in cell cycle progression by regulating the transcription of genes required for mitosis and cytokinesis. In many tumors, B-MYB and FOXM1 are overexpressed as part of the proliferation signature. However, the transcriptional targets that are important for oncogenesis have not been identified. Given that mitotic kinesins are highly expressed in cancer cells and that selected kinesins have been reported as target genes of MMB-FOXM1, we sought to determine which mitotic kinesins are directly regulated by MMB-FOXM1. We demonstrate that six mitotic kinesins and two microtubule-associated non-motor proteins (MAPs) CEP55 and PRC1 are direct transcriptional targets of MuvB, B-MYB and FOXM1 in breast cancer cells.
Suppression of KIF23 and PRC1 strongly suppressed proliferation of MDA-MB-231 cells. The set of MMB-FOXM1 regulated kinesins genes and 4 additional kinesins which we referred to as the mitotic kinesin signature (MKS) is linked to poor outcome in breast cancer patients. Thus, mitotic kinesins could be used as prognostic biomarker and could be potential therapeutic targets for the treatment of breast cancer.
African trypanosomiasis is a disease endemic to sub-Saharan Africa. It affects humans as well as wild and domestic animals. The human form of the disease is known as sleeping sickness and the animal form as nagana, which are usually fatal if left untreated. The cause of African trypanosomiasis is the unicellular parasite Trypanosoma brucei. During its life cycle, Trypanosoma brucei shuttles between a mammalian host and the tsetse fly vector. In the mammalian host the parasite multiplies as bloodstream form (BSF) extracellularly in the bloodstream or the lymphatic system. Survival of BSF parasites relies on immune evasion by antigenic variation of surface proteins because its extracellular lifestyle leads to direct exposure to immune responses. At any given time each BSF cell expresses a single type of variant surface glycoprotein (VSG) on its surface from a large repertoire. The active VSG is transcribed from one of 15 specialized subtelomeric domains, termed bloodstream expression sites (BESs). The remaining 14 BESs are silenced. This monoallelic expression and periodic switching of the expressed VSG enables to escape the immune response and to establish a persistent infection in the mammalian host. During developmental differentiation from BSF to the insect vector-resident procyclic form (PCF), the active BES is transcriptionally silenced to stop VSG transcription. Thus, all 15 BESs are inactive in the PCF cells as surface protein expression is developmentally regulated.
Previous reports have shown that the telomere complex components TbTRF, TbRAP1 and TbTIF2 are involved in VSG transcriptional regulation. However, the precise nature of their contribution remains unclear. In addition, no information is available about the role of telomeres in the initiation and regulation of developmental BES silencing. To gain insights into the regulatory mechanisms of telomeres on VSG transcription and developmental repression it is therefore essential to identify the complete composition of the trypanosome telomere complex.
To this end, we used two complementary biochemical approaches and quantitative label-free interactomics to determine the composition of telomere protein complexes in T. brucei. Firstly, using a telomeric pull-down assay we found 17 potential telomere-binding proteins including the known telomere-binding proteins TbTRF and TbTIF2. Secondly, by performing a co-immunoprecipitation experiment to elucidate TbTRF interactions we co-purified five proteins. All of these five proteins were also enriched with telomeric DNA in the pull-down assay.
To validate these data, I characterized one of the proteins found in both experiments (TelBP1). In BSF cells, TelBP1 co-localizes with TbTRF and interacts with already described telomere-binding proteins such as TbTRF, TbTIF2 and TbRAP1 indicating that TelBP1 is a novel component of the telomere complex in trypanosomes. Interestingly, protein interaction studies in PCF cells suggested a different telomere complex composition compared to BSF cells. In contrast to known members of the telomere complex, TelBP1 is dispensable for cell viability indicating that its function might be uncoupled from the known telomere-binding proteins. Overexpression of TelBP1 had also no effect on cell viability, but led to the discovery of two additional shorter isoforms of TelBP1. However, their source and function remained elusive.
Although TelBP1 is not essential for cell viability, western blot analysis revealed a 4-fold upregulation of TelBP1 in the BSF stage compared to the PCF stage supporting the concept of a dynamic telomere complex composition. We observed that TelBP1 influences the kinetics of transcriptional BES silencing during developmental transition from BSF to PCF. Deletion of TelBP1 caused faster BES silencing compared to wild-type parasites.
Taken together, TelBP1 function illustrates that developmental BES silencing is a fine-tuned process, which involves stage-specific changes in telomere complex formation.
Optogenetics is a method to control the cell activity with light by expression of a natural or engineered photoreceptor via genetic modification technology. Optogenetics early success came with the light-gated cation channel "Channelrhodopsin-2" in neurons and expanded from neuroscience to other research fields such as cardiac research and cell signaling, also due to the enrichment by new photoreceptors. In this study, I focus on searching and characterizing new photoreceptors to expand the optogenetic tool box. In this work I characterize three newly discovered microbial rhodopsins and some engineered mutants of them.
The first rhodopsin is a proton pump from the diatom Fragilariopsis cylindrus, Fragilariopsis Rhodopsin or abbreviated: FR. I cloned the full-length FR and proved it to be a light-activated proton pump with high efficacy in comparison to Bacteriorhodopsin (BR). During this study, I also developed a new method to improve the plasma membrane targeting of several microbial rhodopsins. I also obtained a FR mutant (channel-like FR or chFR) which behaves like a light-gated proton channel. FR can be used for optogenetic hyperpolarization or alkalization of a cell while the chFR could be used for depolarization or lowering of the cellular pH. The induction of FR expression under iron-limited conditions in the diatom indicated an alternative energy generation mechanism of F. cylindrus when iron-containing enzymes are scarce.
I then characterized a new microbial rhodopsin with novel light-regulated Guanylyl Cyclase (GC) activity. This rhodopsin guanylyl cyclase from the fungus Blastocladiella emersonii (B.e. CyclaseOpsin or BeCyclOp) has been proven by me to be an efficient light-gated GC with high specificity and fast kinetics. BeCyclOp also has a novel structure with eight transmembrane helices, containing a long cytosolic N-terminus which participates in the tight regulation of the GC activity. In collaboration with Prof. Alexander Gottschalk (Univ. Frankfurt/M.), BeCyclOp has been tested in muscle cells and sensory neurons of Caenorhabditis elegans and proven to be a powerful optogenetic tool in a living animal. I also generated a BeCyclOp mutant with enhanced light sensitivity.
Already more than ten years ago, guanylyl cyclase rhodopsins were suggested to exist in Chlamydomonas reinhardtii by analyzing genomic sequence data. But until now no functional proof existed. By further cloning and sequencing I discovered such a rhodopsin with light-regulated guanylyl cyclase activity. This functional Cyclaseopsin (COP6c) is quite different to BeCyclOp, as it was proven to be a light-inhibited GC. Cop6c is much larger than BeCyclOp with a His-Kinase and a response regulator domain between the rhodopsin and the cyclase domain.
I also introduced a new strategy for generating optogenetic tools by fusing the photoactivated adenylyl cyclase bPAC to two different CNG channels. These new tools function via light-gated cAMP production and subsequent CNG channel activation. These tools combined the properties of bPAC (highly sensitive to blue light) and CNG channels (high single-channel conductance and high Ca2+ permeability), as demonstrated by expression in Xenopus oocytes. As a further benefit the fusing of bPAC to CNG channels leads to a bPAC with a more than tenfold reduced dark activity which is a valuable improvement for bPAC itself as an optogenetic tool.
Obligate intracellular Chlamydia trachomatis replicate in a membrane-bound vacuole called inclusion, which serves as a signaling interface with the host cell. Here, we show that the chlamydial deubiquitinating enzyme (Cdu) 1 localizes in the inclusion membrane and faces the cytosol with the active deubiquitinating enzyme domain. The structure of this domain revealed high similarity to mammalian deubiquitinases with a unique α-helix close to the substrate-binding pocket. We identified the apoptosis regulator Mcl-1 as a target that interacts with Cdu1 and is stabilized by deubiquitination at the chlamydial inclusion. A chlamydial transposon insertion mutant in the Cdu1-encoding gene exhibited increased Mcl-1 and inclusion ubiquitination and reduced Mcl-1 stabilization. Additionally, inactivation of Cdu1 led to increased sensitivity of C. trachomatis for IFNγ and impaired infection in mice. Thus, the chlamydial inclusion serves as an enriched site for a deubiquitinating activity exerting a function in selective stabilization of host proteins and protection from host defense.
Objective: To investigate the association between levodopa‐induced dyskinesias and striatal cholinergic activity in patients with Parkinson's disease.
Methods: This study included 13 Parkinson's disease patients with peak‐of‐dose levodopa‐induced dyskinesias, 12 nondyskinetic patients, and 12 healthy controls. Participants underwent 5‐[\(^{123}\)I]iodo‐3‐[2(S)‐2‐azetidinylmethoxy]pyridine single‐photon emission computed tomography, a marker of nicotinic acetylcholine receptors, [\(^{123}\)I]N‐ω‐fluoropropyl‐2β‐carbomethoxy‐3β‐(4‐iodophenyl)nortropane single‐photon emission computed tomography, to measure dopamine reuptake transporter density and 2‐[\(^{18}\)F]fluoro‐2‐deoxyglucose positron emission tomography to assess regional cerebral metabolic activity. Striatal binding potentials, uptake values at basal ganglia structures, and correlations with clinical variables were analyzed.
Results: Density of nicotinic acetylcholine receptors in the caudate nucleus of dyskinetic subjects was similar to that of healthy controls and significantly higher to that of nondyskinetic patients, in particular, contralaterally to the clinically most affected side.
Interpretation: Our findings support the hypothesis that the expression of dyskinesia may be related to cholinergic neuronal excitability in a dopaminergic‐depleted striatum. Cholinergic signaling would play a role in maintaining striatal dopaminergic responsiveness, possibly defining disease phenotype and progression.
A Good Practice is a practice that works well, produces good results, and is recommended as a model. MACVIA-ARIA Sentinel Network (MASK), the new Allergic Rhinitis and its Impact on Asthma (ARIA) initiative, is an example of a Good Practice focusing on the implementation of multi-sectoral care pathways using emerging technologies with real life data in rhinitis and asthma multi-morbidity. The European Union Joint Action on Chronic Diseases and Promoting Healthy Ageing across the Life Cycle (JA-CHRODIS) has developed a checklist of 28 items for the evaluation of Good Practices. SUNFRAIL (Reference Sites Network for Prevention and Care of Frailty and Chronic Conditions in community dwelling persons of EU Countries), a European Union project, assessed whether MASK is in line with the 28 items of JA-CHRODIS. A short summary was proposed for each item and 18 experts, all members of ARIA and SUNFRAIL from 12 countries, assessed the 28 items using a Survey Monkey-based questionnaire. A visual analogue scale (VAS) from 0 (strongly disagree) to 100 (strongly agree) was used. Agreement equal or over 75% was observed for 14 items (50%). MASK is following the JA-CHRODIS recommendations for the evaluation of Good Practices.
Human herpesvirus 6A (HHV-6A) and 6B (HHV-6B) are two different species of betaherpesviruses that integrate into sub-telomeric ends of human chromosomes, for which different prevalence rates of integration have been reported. It has been demonstrated that integrated viral genome is stable and is fully retained. However, study of chromosomally integrated viral genome in individuals carrying inherited HHV-6 (iciHHV-6) showed unexpected number of viral DR copies. Hence, we created an in vitro infection model and studied retention of full or partial viral genome over a period of time. We observed an exceptional event where cells retained viral direct repeats (DRs) alone in the absence of the full viral genome. Finally, we found evidence for non-telomeric integration of HHV-6A DR in both cultured cells and in an iciHHV-6 individual. Our results shed light on several novel features of HHV-6A chromosomal integration and provide valuable information for future screening techniques.
TNF receptor type 2 (TNFR2) has gained attention as a costimulatory receptor for T cells and as critical factor for the development of regulatory T cells (Treg) and myeloid suppressor cells. Using the TNFR2-specific agonist TNCscTNF80, direct effects of TNFR2 activation on myeloid cells and T cells were investigated in mice. \(In\) \(vitro\), TNCscTNF80 induced T cell proliferation in a costimulatory fashion, and also supported \(in\) \(vitro\) expansion of Treg cells. In addition, activation of TNFR2 retarded differentiation of bone marrow-derived immature myeloid cells in culture and reduced their suppressor function. \(In\) \(vivo\) application of TNCscTNF80-induced mild myelopoiesis in naïve mice without affecting the immune cell composition. Already a single application expanded Treg cells and improved suppression of CD4 T cells in mice with chronic inflammation. By contrast, multiple applications of the TNFR2 agonist were required to expand Treg cells in naïve mice. Improved suppression of T cell proliferation depended on expression of TNFR2 by T cells in mice repeatedly treated with TNCscTNF80, without a major contribution of TNFR2 on myeloid cells. Thus, TNFR2 activation on T cells in naïve mice can lead to immune suppression \(in\) \(vivo\). These findings support the important role of TNFR2 for Treg cells in immune regulation.
Background:
Accidents or neurodegenerative diseases like amyotrophic lateral sclerosis (ALS) can lead to progressing, extensive, and complete paralysis leaving patients aware but unable to communicate (locked-in state). Brain-computer interfaces (BCI) based on electroencephalography represent an important approach to establish communication with these patients. The most common BCI for communication rely on the P300, a positive deflection arising in response to rare events. To foster broader application of BCIs for restoring lost function, also for end-users with impaired vision, we explored whether there were specific time windows during the day in which a P300 driven BCI should be preferably applied.
Methods:
The present study investigated the influence of time of the day and modality (visual vs. auditory) on P300 amplitude and latency. A sample of 14 patients (end-users) with ALS and 14 healthy age matched volunteers participated in the study and P300 event-related potentials (ERP) were recorded at four different times (10, 12 am, 2, & 4 pm) during the day.
Results:
Results indicated no differences in P300 amplitudes or latencies between groups (ALS patients v. healthy participants) or time of measurement. In the auditory condition, latencies were shorter and amplitudes smaller as compared to the visual condition.
Conclusion:
Our findings suggest applicability of EEG/BCI sessions in patients with ALS throughout normal waking hours. Future studies using actual BCI systems are needed to generalize these findings with regard to BCI effectiveness/efficiency and other times of day.
This doctoral thesis provides a classification of equivariant star products (star products together with quantum momentum maps) in terms of equivariant de Rham cohomology. This classification result is then used to construct an analogon of the Kirwan map from which one can directly obtain the characteristic class of certain reduced star products on Marsden-Weinstein reduced symplectic manifolds from the equivariant characteristic class of their corresponding unreduced equivariant star product. From the surjectivity of this map one can conclude that every star product on Marsden-Weinstein reduced symplectic manifolds can (up to equivalence) be obtained as a reduced equivariant star product.
Past and the projected future climate change in Afghanistan has been analyzed systematically and differentiated with respect to its different climate regions to gain some first quantitative insights into Afghanistan’s vulnerability to ongoing and future climate changes. For this purpose, temperature, precipitation and five additional climate indices for extremes and agriculture assessments (heavy precipitation; spring precipitation; growing season length (GSL), the Heat Wave Magnitude Index (HWMI); and the Standardized Precipitation Evapotranspiration Index (SPEI)) from the reanalysis data were examined for their consistency to identify changes in the past (data since 1950). For future changes (up to the year 2100), the same parameters were extracted from an ensemble of 12 downscaled regional climate models (RCM) of the Coordinated Regional Climate Downscaling Experiment (CORDEX)-South Asia simulations for low and high emission scenarios (Representative Concentration Pathways 4.5 and 8.5). In the past, the climatic changes were mainly characterized by a mean temperature increase above global level of 1.8 °C from 1950 to 2010; uncertainty with regard to reanalyzed rainfall data limited a thorough analysis of past changes. Climate models projected the temperature trend to accelerate in the future, depending strongly on the global carbon emissions (2006–2050 Representative Concentration Pathways 4.5/8.5: 1.7/2.3 °C; 2006–2099: 2.7/6.4 °C, respectively). Despite the high uncertainty with regard to precipitation projections, it became apparent that the increasing evapotranspiration is likely to exacerbate Afghanistan’s already existing water stress, including a very strong increase of frequency and magnitude of heat waves. Overall, the results show that in addition to the already extensive deficiency in adaptation to current climate conditions, the situation will be aggravated in the future, particularly in regard to water management and agriculture. Thus, the results of this study underline the importance of adequate adaptation to climate change in Afghanistan. This is even truer taking into account that GSL is projected to increase substantially by around 20 days on average until 2050, which might open the opportunity for extended agricultural husbandry or even additional harvests when water resources are properly managed.
Using color in user interface design is both art and science. Often, designers focus on aesthetic properties of color, but neglect that it also carries meaning and entails profound psychological consequences. Color psychology, filling this gap, is in its infancy, and lacks a theoretical approach that predicts and explains color-meaning associations shared by a large group of people in a large variety of contexts.
To amend this situation, this work develops Conceptual Metaphor Theory of Color (CMToC), which predicts and explains cross-cultural and experience-based semantic color associations. The theory is based on the idea from cognitive linguistics that the study of metaphorical language provides valuable insights into our mental models involving color. A discussion of three types of metaphors that cover associations with physical and abstract concepts in light of existing empirical evidence provides the basis for deriving empirical research questions.
The first research question addresses the use of color for conveying physical information like weight in user interfaces. The results of four online surveys involving a total of 295 German and Japanese participants show the relative impact of hue, saturation and brightness for associations with 16 physical properties. Two thirds of these color associations were correctly predicted by CMToC. Participants frequently matched physical properties to colors based on sensorimotor correspondences and participants of both cultures did not considerably vary in their performance.
The second research question addresses the use of color for conveying abstract information like importance in user interfaces. In one experimental study, a total of 75 German and Japanese participants validated color-to-abstract mappings in form of color population stereotypes like important is dark. The majority of these color associations (86%) were correctly predicted by CMToC. Again, participants of both cultures did not considerably vary in their performance.
The third research question addresses whether predicted color associations with physical and abstract information are processed automatically as a precondition for intuitive use. The results of three studies involving a total of 85 German and Japanese participants show on the example of temperature that color automatically influences the identification speed of related physical properties, but not vice versa. Color and abstract information were not automatically associated.
As a result of these studies it can be concluded that predictions of CMToC are cross-culturally valid for user interface design. Derived implicit associations with physical properties and explicit associations with abstract concepts can inform design decisions in both hard- and software user interface design.
The instructive component of waggle dance communication has been shown to increase resource uptake of Apis mellifera colonies in highly heterogeneous resource environments, but an assessment of its relevance in temperate landscapes with different levels of resource heterogeneity is currently lacking. We hypothesized that the advertisement of resource locations via dance communication would be most relevant in highly heterogeneous landscapes with large spatial variation of floral resources. To test our hypothesis, we placed 24 Apis mellifera colonies with either disrupted or unimpaired instructive component of dance communication in eight Central European agricultural landscapes that differed in heterogeneity and resource availability. We monitored colony weight change and pollen harvest as measure of foraging success. Dance disruption did not significantly alter colony weight change, but decreased pollen harvest compared to the communicating colonies by 40%. There was no general effect of resource availability on nectar or pollen foraging success, but the effect of landscape heterogeneity on nectar uptake was stronger when resource availability was high. In contrast to our hypothesis, the effects of disrupted bee communication on nectar and pollen foraging success were not stronger in landscapes with heterogeneous compared to homogenous resource environments. Our results indicate that in temperate regions intra-colonial communication of resource locations benefits pollen foraging more than nectar foraging, irrespective of landscape heterogeneity. We conclude that the so far largely unexplored role of dance communication in pollen foraging requires further consideration as pollen is a crucial resource for colony development and health.
Background:
Mechanical circulatory support is a common practice nowadays in the management of patients after cardiogenic shock due to myocardial infarction. The single or combined use of one or more devices for mechanical support depends not only on the advantage or disadvantage of these devices but also on the timing of use of these devices before the development of multi organ failure. In our case we used more than one tool for mechanical circulatory support during the prolonged and complicated course of our patient with postcardiotomy cardiogenic shock after coronary artery bypass surgery.
Case Presentation:
We describe the combined use of Impella 5.0 and veno- pulmonary extra corporeal membrane oxygenation (VP-ECMO) for biventricular failure in a 52 years—old man. He presented with cardiogenic shock after inferior wall ST-elevation myocardial infarction. After emergency coronary artery bypass surgery and failure to wean from extracorporeal circulation we employed V-P ECMO and consecutively Impella 5.0 to manage the primarily failing right and secondarily failing left ventricles.
He remained hemodynamically stable on both Impella 5.0 and VP-ECMO until Heart Mate II left ventricular assist device implantation on the 14th postoperative day. Right sided support was weaned on 66th postoperative day. The patient remained in the intensive care unit for 77 days. During his prolonged stay, he underwent renal replacement therapy and tracheostomy with complete recovery. Six months later, he was successfully heart transplanted and has completed three and half years of unremarkable follow up.
Conclusions:
The combined use of VP ECMO and Impella 5.0 is effective in the management of postcardiotomy biventricular failure as a bridge for further mechanical support or heart transplantation.
A commentary on: Feeling the Conflict: The Crucial Role of Conflict Experience in Adaptationby Desender, K., Van Opstal, F., and Van den Bussche, E. (2014). Psychol. Sci. 25, 675–683. doi:10.1177/0956797613511468
Conflict adaptation in masked priming has recently been proposed to rely not on successful conflictresolution but rather on conflict experience (Desender et al., 2014). We re-assessed this proposal ina direct replication and also tested a potential confound due toconflict strength. The data supported this alternative view, but also failed to replicate basic conflict adaptation effects of the original studydespite considerable power.
Some members of the physiological human microbiome occasionally cause life-threatening disease even in immunocompetent individuals. A prime example of such a commensal pathogen is Neisseria meningitidis, which normally resides in the human nasopharynx but is also a leading cause of sepsis and epidemic meningitis. Using N. meningitidis as model organism, we tested the hypothesis that virulence of commensal pathogens is a consequence of within host evolution and selection of invasive variants due to mutations at contingency genes, a mechanism called phase variation. In line with the hypothesis that phase variation evolved as an adaptation to colonize diverse hosts, computational comparisons of all 27 to date completely sequenced and annotated meningococcal genomes retrieved from public databases showed that contingency genes are indeed enriched for genes involved in host interactions. To assess within-host genetic changes in meningococci, we further used ultra-deep whole-genome sequencing of throat-blood strain pairs isolated from four patients suffering from invasive meningococcal disease. We detected up to three mutations per strain pair, affecting predominantly contingency genes involved in type IV pilus biogenesis. However, there was not a single (set) of mutation(s) that could invariably be found in all four pairs of strains. Phenotypic assays further showed that these genetic changes were generally not associated with increased serum resistance, higher fitness in human blood ex vivo or differences in the interaction with human epithelial and endothelial cells in vitro. In conclusion, we hypothesize that virulence of meningococci results from accidental emergence of invasive variants during carriage and without within host evolution of invasive phenotypes during disease progression in vivo.
Background
The lytic cycle of the protozoan parasite \(Toxoplasma\) \(gondii\), which involves a brief sojourn in the extracellular space, is characterized by defined transcriptional profiles. For an obligate intracellular parasite that is shielded from the cytosolic host immune factors by a parasitophorous vacuole, the brief entry into the extracellular space is likely to exert enormous stress. Due to its role in cellular stress response, we hypothesize that translational control plays an important role in regulating gene expression in \(Toxoplasma\) during the lytic cycle. Unlike transcriptional profiles, insights into genome-wide translational profiles of \(Toxoplasma\) \(gondii\) are lacking.
Methods
We have performed genome-wide ribosome profiling, coupled with high throughput RNA sequencing, in intracellular and extracellular \(Toxoplasma\) \(gondii\) parasites to investigate translational control during the lytic cycle.
Results
Although differences in transcript abundance were mostly mirrored at the translational level, we observed significant differences in the abundance of ribosome footprints between the two parasite stages. Furthermore, our data suggest that mRNA translation in the parasite is potentially regulated by mRNA secondary structure and upstream open reading frames.
Conclusion
We show that most of the \(Toxoplasma\) genes that are dysregulated during the lytic cycle are translationally regulated.