TY - THES A1 - Forster, Johannes T1 - Variational Approach to the Modeling and Analysis of Magnetoelastic Materials T1 - Variationeller Zugang zu Modellierung und Analysis Magnetoelastischer Materialien N2 - This doctoral thesis is concerned with the mathematical modeling of magnetoelastic materials and the analysis of PDE systems describing these materials and obtained from a variational approach. The purpose is to capture the behavior of elastic particles that are not only magnetic but exhibit a magnetic domain structure which is well described by the micromagnetic energy and the Landau-Lifshitz-Gilbert equation of the magnetization. The equation of motion for the material’s velocity is derived in a continuum mechanical setting from an energy ansatz. In the modeling process, the focus is on the interplay between Lagrangian and Eulerian coordinate systems to combine elasticity and magnetism in one model without the assumption of small deformations. The resulting general PDE system is simplified using special assumptions. Existence of weak solutions is proved for two variants of the PDE system, one including gradient flow dynamics on the magnetization, and the other featuring the Landau-Lifshitz-Gilbert equation. The proof is based on a Galerkin method and a fixed point argument. The analysis of the PDE system with the Landau-Lifshitz-Gilbert equation uses a more involved approach to obtain weak solutions based on G. Carbou and P. Fabrie 2001. N2 - Die vorliegende Doktorarbeit beschäftigt sich mit der mathematischen Modellierung magnetoelastischer Materialien und der Analysis von Systemen partieller Differentialgleichungen für diese Materialien. Die Herleitung der partiellen Differentialgleichungen erfolgt mittels eines variationellen Zugangs. Ziel ist es, das Verhalten elastischer Teilchen zu beschreiben, welche nicht nur magnetisch sind, sondern sich durch eine magnetische Domänenstruktur auszeichnen. Diese Struktur wird beschrieben durch die mikromagnetische Energie und die Landau-Lifshitz-Gilbert Gleichung der Magnetisierung. Die Bewegungsgleichung für die Geschwindigkeit des Materials ist in einem kontinuumsmechanischen Setting von einer Energiegleichung abgeleitet. In der Modellierung liegt der Fokus auf dem Zusammenspiel von Lagrange’schen und Euler’schen Koordinaten, um Elastizität und Magnetismus in einem Modell zu kombinieren. Dies geschieht ohne die Annahme kleiner Deformationen. Das resultierende allgemeine System partieller Differentialgleichungen wird durch spezielle Annahmen vereinfacht und es wird die Existenz von schwachen Lösungen gezeigt. Der Beweis wird für zwei Varianten des Differentialgleichungssystems geführt. Das erste System enthält die Beschreibung der Dynamik der Magnetisierung mittels Gradientenfluss, im zweiten wird die Dynamik mittels Landau-Lifshitz-Gilbert Gleichung beschrieben. Schlüsselidee des Beweises ist ein Galerkin-Ansatz, kombiniert mit einem Fixpunkt-Argument. Zum Beweis der Existenz schwacher Lösungen des Systems mit Landau-Lifshitz-Gilbert Gleichung wird eine aufwändigere Methode herangezogen, welche auf einer Arbeit von G. Carbou und P. Fabrie aus 2001 beruht. KW - Magnetoelastizität KW - Mikromagnetismus KW - Mathematische Modellierung KW - Galerkin-Methode KW - Differentialgleichungssystem KW - Partielle Differentialgleichungen KW - Existenz schwacher Lösungen KW - PDEs KW - Mathematical modeling KW - Calculus of variations Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-147226 ER - TY - JOUR A1 - Busch, Albert A1 - Hoffjan, Sabine A1 - Bergmann, Frauke A1 - Hartung, Birgit A1 - Jung, Helena A1 - Hanel, Daniela A1 - Tzschach, Andeas A1 - Kadar, Janos A1 - von Kodolitsch, Yskert A1 - Germer, Christoph-Thomas A1 - Trobisch, Heiner A1 - Strasser, Erwin A1 - Wildenauer, René T1 - Vascular type Ehlers-Danlos syndrome is associated with platelet dysfunction and low vitamin D serum concentration JF - Orphanet Journal of Rare Diseases N2 - Background The vascular type represents a very rare, yet the clinically most fatal entity of Ehlers-Danlos syndrome (EDS). Patients are often admitted due to arterial bleedings and the friable tissue and the altered coagulation contribute to the challenge in treatment strategies. Until now there is little information about clotting characteristics that might influence hemostasis decisively and eventually worsen emergency situations. Results 22 vascular type EDS patients were studied for hemoglobin, platelet volume and count, Quick and activated partial thromboplastin time, fibrinogen, factor XIII, von Willebrand disease, vitamin D and platelet aggregation by modern standard laboratory methods. Results show a high prevalence of over 50 % for platelet aggregation disorders in vascular type EDS patients, especially for collagen and epinephrine induced tests, whereas the plasmatic cascade did not show any alterations. Additionally, more than half of the tested subjects showed low vitamin D serum levels, which might additionally affect vascular wall integrity. Conclusion The presented data underline the importance of detailed laboratory screening methods in vascular type EDS patients in order to allow for targeted application of platelet-interacting substances that might be of decisive benefit in the emergency setting. KW - vascular type KW - vitamin D KW - Ehlers-Danlos syndrome KW - EDS KW - platelet dysfunction Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-147757 VL - 11 IS - 111 ER - TY - JOUR A1 - Bemm, Felix A1 - Becker, Dirk A1 - Larisch, Christina A1 - Kreuzer, Ines A1 - Escalante-Perez, Maria A1 - Schulze, Waltraud X. A1 - Ankenbrand, Markus A1 - Van de Weyer, Anna-Lena A1 - Krol, Elzbieta A1 - Al-Rasheid, Khaled A. A1 - Mithöfer, Axel A1 - Weber, Andreas P. A1 - Schultz, Jörg A1 - Hedrich, Rainer T1 - Venus flytrap carnivorous lifestyle builds on herbivore defense strategies JF - Genome Research N2 - Although the concept of botanical carnivory has been known since Darwin's time, the molecular mechanisms that allow animal feeding remain unknown, primarily due to a complete lack of genomic information. Here, we show that the transcriptomic landscape of the Dionaea trap is dramatically shifted toward signal transduction and nutrient transport upon insect feeding, with touch hormone signaling and protein secretion prevailing. At the same time, a massive induction of general defense responses is accompanied by the repression of cell death-related genes/processes. We hypothesize that the carnivory syndrome of Dionaea evolved by exaptation of ancient defense pathways, replacing cell death with nutrient acquisition. KW - Dionaea-muscipula ellis KW - Plant utricularia-gibba KW - Programmed cell-death KW - Genomics data sets KW - RNA-SEQ data KW - Arabidopsis-thaliana KW - Jasmonate perception KW - Action potentials KW - Stress responses KW - Wonderful plants Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-188799 VL - 26 IS - 6 ER - TY - JOUR A1 - Böhm, J. A1 - Scherzer, S. A1 - Shabala, S. A1 - Krol, E. A1 - Neher, E. A1 - Mueller, T. D. A1 - Hedrich, R. T1 - Venus flytrap HKT1-type channel provides for prey sodium uptake into carnivorous plant without conflicting with electrical excitability JF - Molecular Plant N2 - The animal diet of the carnivorous Venus flytrap, Dionaea muscipula, contains a sodium load that enters the capture organ via an HKT1-type sodium channel, expressed in special epithelia cells on the inner trap lobe surface. DmHKT1 expression and sodium uptake activity is induced upon prey contact. Here, we analyzed the HKT1 properties required for prey sodium osmolyte management of carnivorous Dionaea. Analyses were based on homology modeling, generation of model-derived point mutants, and their functional testing in Xenopus oocytes. We showed that the wild-type HKT1 and its Na\(^+\)- and K\(^+\)-permeable mutants function as ion channels rather than K\(^+\) transporters driven by proton or sodium gradients. These structural and biophysical features of a high-capacity, Na\(^+\)-selective ion channel enable Dionaea glands to manage prey-derived sodium loads without confounding the action potential-based information management of the flytrap. KW - sodium channel KW - HKT1 KW - Dionaea muscipula KW - action potential KW - glands KW - sodium uptake Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-189803 VL - 9 IS - 3 ER - TY - JOUR A1 - Koenig, Sebastian A1 - Wolf, Reinhard A1 - Heisenberg, Martin T1 - Vision in Flies: Measuring the Attention Span JF - PLoS ONE N2 - A visual stimulus at a particular location of the visual field may elicit a behavior while at the same time equally salient stimuli in other parts do not. This property of visual systems is known as selective visual attention (SVA). The animal is said to have a focus of attention (FoA) which it has shifted to a particular location. Visual attention normally involves an attention span at the location to which the FoA has been shifted. Here the attention span is measured in Drosophila. The fly is tethered and hence has its eyes fixed in space. It can shift its FoA internally. This shift is revealed using two simultaneous test stimuli with characteristic responses at their particular locations. In tethered flight a wild type fly keeps its FoA at a certain location for up to 4s. Flies with a mutation in the radish gene, that has been suggested to be involved in attention-like mechanisms, display a reduced attention span of only 1s. KW - eye movements KW - attention KW - Drosophila melanogaster KW - torque KW - motion KW - insect flight KW - eyes KW - vision Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-179947 VL - 11 IS - 2 ER - TY - JOUR A1 - Koenig, Sebastian A1 - Wolf, Reinhard A1 - Heisenberg, Martin T1 - Visual Attention in Flies-Dopamine in the Mushroom Bodies Mediates the After-Effect of Cueing JF - PLoS ONE N2 - Visual environments may simultaneously comprise stimuli of different significance. Often such stimuli require incompatible responses. Selective visual attention allows an animal to respond exclusively to the stimuli at a certain location in the visual field. In the process of establishing its focus of attention the animal can be influenced by external cues. Here we characterize the behavioral properties and neural mechanism of cueing in the fly Drosophila melanogaster. A cue can be attractive, repulsive or ineffective depending upon (e.g.) its visual properties and location in the visual field. Dopamine signaling in the brain is required to maintain the effect of cueing once the cue has disappeared. Raising or lowering dopamine at the synapse abolishes this after-effect. Specifically, dopamine is necessary and sufficient in the αβ-lobes of the mushroom bodies. Evidence is provided for an involvement of the αβ\(_{posterior}\) Kenyon cells. KW - dopamine transporters KW - Drosophila melanogaster KW - synapses KW - dopaminergics KW - dopamine KW - sensory cues KW - RNA interference KW - vision Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-179564 VL - 11 IS - 8 ER - TY - JOUR A1 - Estrecho, E. A1 - Gao, T. A1 - Brodbeck, S. A1 - Kamp, M. A1 - Schneider, C. A1 - Höfling, S. A1 - Truscott, A. G. A1 - Ostrovskaya, E. A. T1 - Visualising Berry phase and diabolical points in a quantum exciton-polariton billiard JF - Scientific Reports N2 - Diabolical points (spectral degeneracies) can naturally occur in spectra of two-dimensional quantum systems and classical wave resonators due to simple symmetries. Geometric Berry phase is associated with these spectral degeneracies. Here, we demonstrate a diabolical point and the corresponding Berry phase in the spectrum of hybrid light-matter quasiparticles—exciton-polaritons in semiconductor microcavities. It is well known that sufficiently strong optical pumping can drive exciton-polaritons to quantum degeneracy, whereby they form a macroscopically populated quantum coherent state similar to a Bose-Einstein condensate. By pumping a microcavity with a spatially structured light beam, we create a two-dimensional quantum billiard for the exciton-polariton condensate and demonstrate a diabolical point in the spectrum of the billiard eigenstates. The fully reconfigurable geometry of the potential walls controlled by the optical pump enables a striking experimental visualization of the Berry phase associated with the diabolical point. The Berry phase is observed and measured by direct imaging of the macroscopic exciton-polariton probability densities. KW - Berry phase KW - diabolical points KW - quantum billiard KW - exciton-polariton Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167496 VL - 6 IS - 37653 ER - TY - JOUR A1 - Hennighausen, Christine A1 - Hudders, Liselot A1 - Lange, Benjamin P. A1 - Fink, Hanna T1 - What If the Rival Drives a Porsche? Luxury Car Spending as a Costly Signal in Male Intrasexual Competition JF - Evolutionary Psychology N2 - Previous research found that men conspicuously consume luxury products to attract a mate and to signal their mate value. However, these studies have yet neglected to investigate the function of male conspicuous consumption in same-sex competition. Given that intersexual selection and intrasexual selection are closely related processes, it stands to reason that a further function of male conspicuous consumption could be to impress and deter same-sex rivals. An 2 (intrasexual competition context vs. control) × 2 (conspicuous luxury vs. inconspicuous nonluxury) between-subjects experimental study conducted with an Amazon Mechanical Turk sample (N = 160) revealed that men reported both higher liking of and an intent to purchase a conspicuous luxury car compared to an inconspicuous nonluxury car due to increased feelings of social status. This effect was stronger in the intrasexual competition than in the control context. An additional perception study using a single-factor between-subjects design (conspicuous luxury vs. inconspicuous nonluxury car) among German men (N = 405) indicated that male participants rated a man who displayed a conspicuous luxury car more as a rival and mate poacher and less as a friend. They further perceived him to be superior on various mate value characteristics (i.e., attractiveness, intelligence, ambition, and status) and rated him as more oriented toward short-term mating. In sum, our findings add to previous research in the field of evolutionary consumer psychology by suggesting that male conspicuous consumption of luxuries may also serve a function in male–male competition. KW - costly KW - dual function KW - intrasexual competition KW - men KW - luxury brands KW - conspicuous consumption KW - signaling KW - evolutionary consumer psychology Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-163481 VL - 14 IS - 4 ER - TY - JOUR A1 - Burns, Alan J. A1 - Goldstein, Allan M. A1 - Newgreen, Donald F. A1 - Stamp, Lincon A1 - Schäfer, Karl-Herbert A1 - Metzger, Marco A1 - Hotta, Ryo A1 - Young, Heather M. A1 - Andrews, Peter W. A1 - Thapar, Nikhil A1 - Belkind-Gerson, Jaime A1 - Bondurand, Nadege A1 - Bornstein, Joel C. A1 - Chan, Wood Yee A1 - Cheah, Kathryn A1 - Gershon, Michael D. A1 - Heuckeroth, Robert O. A1 - Hofstra, Robert M.W. A1 - Just, Lothar A1 - Kapur, Raj P. A1 - King, Sebastian K. A1 - McCann, Conor J. A1 - Nagy, Nandor A1 - Ngan, Elly A1 - Obermayr, Florian A1 - Pachnis, Vassilis A1 - Pasricha, Pankaj J. A1 - Sham, Mai Har A1 - Tam, Paul A1 - Vanden Berghe, Pieter T1 - White paper on guidelines concerning enteric nervous system stem cell therapy for enteric neuropathies JF - Developmental Biology N2 - Over the last 20 years, there has been increasing focus on the development of novel stem cell based therapies for the treatment of disorders and diseases affecting the enteric nervous system (ENS) of the gastrointestinal tract (so-called enteric neuropathies). Here, the idea is that ENS progenitor/stem cells could be transplanted into the gut wall to replace the damaged or absent neurons and glia of the ENS. This White Paper sets out experts' views on the commonly used methods and approaches to identify, isolate, purify, expand and optimize ENS stem cells, transplant them into the bowel, and assess transplant success, including restoration of gut function. We also highlight obstacles that must be overcome in order to progress from successful preclinical studies in animal models to ENS stem cell therapies in the clinic. KW - Neural crest cells KW - Rat mynteric plexus KW - Intestinal pseudoobstruction KW - Hypertrophic pyloric-stenosis KW - Hirschsprung disease liability KW - Slow-transit constipation KW - Oxide synthase gene KW - Term follow-up KW - Nitric-oxide KW - In-vivo KW - Enteric nervous system KW - Enteric neuropathies KW - Stem cells KW - Cell replacement therapy KW - Hirschsprung disease Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-187415 VL - 417 IS - 2 ER - TY - JOUR A1 - Brunet, Frédéric G. A1 - Volff, Jean-Nicolas A1 - Schartl, Manfred T1 - Whole Genome Duplications Shaped the Receptor Tyrosine Kinase Repertoire of Jawed Vertebrates JF - Genome Biology Evolution N2 - The receptor tyrosine kinase (RTK) gene family, involved primarily in cell growth and differentiation, comprises proteins with a common enzymatic tyrosine kinase intracellular domain adjacent to a transmembrane region. The amino-terminal portion of RTKs is extracellular and made of different domains, the combination of which characterizes each of the 20 RTK subfamilies among mammals. We analyzed a total of 7,376 RTK sequences among 143 vertebrate species to provide here the first comprehensive census of the jawed vertebrate repertoire. We ascertained the 58 genes previously described in the human and mouse genomes and established their phylogenetic relationships. We also identified five additional RTKs amounting to a total of 63 genes in jawed vertebrates. We found that the vertebrate RTK gene family has been shaped by the two successive rounds of whole genome duplications (WGD) called 1R and 2R (1R/2R) that occurred at the base of the vertebrates. In addition, the Vegfr and Ephrin receptor subfamilies were expanded by single gene duplications. In teleost fish, 23 additional RTK genes have been retained after another expansion through the fish-specific third round (3R) of WGD. Several lineage-specific gene losses were observed. For instance, birds have lost three RTKs, and different genes are missing in several fish sublineages. The RTK gene family presents an unusual high gene retention rate from the vertebrate WGDs (58.75% after 1R/2R, 64.4% after 3R), resulting in an expansion that might be correlated with the evolution of complexity of vertebrate cellular communication and intracellular signaling. KW - receptor tyrosine kinase KW - vertebrates KW - deuterostomes KW - whole genome duplications Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146988 VL - 8 IS - 15 ER -