13 research outputs found

    Explicit de Sitter Flux Vacua for Global String Models with Chiral Matter

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    We address the open question of performing an explicit stabilisation of all closed string moduli (including dilaton, complex structure and Kaehler moduli) in fluxed type IIB Calabi-Yau compactifications with chiral matter. Using toric geometry we construct Calabi-Yau manifolds with del Pezzo singularities. D-branes located at such singularities can support the Standard Model gauge group and matter content. In order to control complex structure moduli stabilisation we consider Calabi-Yau manifolds which exhibit a discrete symmetry that reduces the effective number of complex structure moduli. We calculate the corresponding periods in the symplectic basis of invariant three-cycles and find explicit flux vacua for concrete examples. We compute the values of the flux superpotential and the string coupling at these vacua. Starting from these explicit complex structure solutions, we obtain AdS and dS minima where the Kaehler moduli are stabilised by a mixture of D-terms, non-perturbative and perturbative alpha'-corrections as in the LARGE Volume Scenario. In the considered example the visible sector lives at a dP_6 singularity which can be higgsed to the phenomenologically interesting class of models at the dP_3 singularity.Comment: 49 pages, 5 figures; v2: references adde

    ATP-Evoked Intracellular Ca Signaling of Different Supporting Cells in the Hearing Mouse Hemicochlea

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    Hearing and its protection is regulated by ATP-evoked Ca2+ signaling in the supporting cells of the organ of Corti, however, the unique anatomy of the cochlea hampers observing these mechanisms. For the first time, we have performed functional ratiometric Ca2+ imaging (fura-2) in three different supporting cell types in the hemicochlea preparation of hearing mice to measure purinergic receptor-mediated Ca2+ signaling in pillar, Deiters' and Hensen's cells. Their resting [Ca2+]i was determined and compared in the same type of preparation. ATP evoked reversible, repeatable and dose-dependent Ca2+ transients in all three cell types, showing desensitization. Inhibiting the Ca2+ signaling of the ionotropic P2X (omission of extracellular Ca2+) and metabotropic P2Y purinergic receptors (depletion of intracellular Ca2+ stores) revealed the involvement of both receptor types. Detection of P2X2,3,4,6,7 and P2Y1,2,6,12,14 receptor mRNAs by RT-PCR supported this finding and antagonism by PPADS suggested different functional purinergic receptor population in pillar versus Deiters' and Hensen's cells. The sum of the extra- and intracellular Ca2+-dependent components of the response was about equal with the control ATP response (linear additivity) in pillar cells, and showed supralinearity in Deiters' and Hensen's cells. Calcium-induced calcium release might explain this synergistic interaction. The more pronounced Ca2+ leak from the endoplasmic reticulum in Deiters' and Hensen's cells, unmasked by cyclopiazonic acid, may also suggests the higher activity of the internal stores in Ca2+ signaling in these cells. Differences in Ca2+ homeostasis and ATP-induced Ca2+ signaling might reflect the distinct roles these cells play in cochlear function and pathophysiology

    Preferences of patients undergoing hemodialysis – results from a questionnaire-based study with 4,518 patients

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    Inger Miriam Janssen,1 Ansgar Gerhardus,2,3 Gero D von Gersdorff,4 Conrad August Baldamus,4 Mathias Schaller,4 Claudia Barth,5 Fueloep Scheibler6 1Department of Epidemiology and International Public Health, Bielefeld University, Bielefeld, Germany; 2Department for Health Services Research, University of Bremen, Bremen, Germany; 3Health Sciences Bremen, University of Bremen, Bremen, Germany; 4Department of Internal Medicine II, University Hospital of Cologne, Cologne, Germany; 5KfH Kuratorium fuer Dialyse und Nierentransplantation e.V., Neu-Isenburg, Germany; 6Department of Non-Drug Interventions, Institute for Quality and Efficiency in Health Care, Cologne, Germany Background: Chronic kidney disease is an increasing health problem worldwide and in its final stage (stage V) can only be treated by renal replacement therapy, mostly hemodialysis. Hemodialysis has a major influence on the everyday life of patients and many patients report dissatisfaction with treatment. Little is known about which aspects of treatment are considered important by hemodialysis patients. The objective of this study was to rate the relative importance of different outcomes for hemodialysis patients and to analyze whether the relative importance differed among subgroups of patients.Patients and methods: Within the framework of a yearly questionnaire which is distributed among patients receiving hemodialysis by the largest hemodialysis provider in Germany, we assessed the relative importance of 23 outcomes as rated on a discrete visual analog scale. Descriptive statistics were used to rank the outcomes. Subgroup analyses were performed using Mann–Whitney U or Kruskal–Wallis tests.Results: Questionnaires of 4,518 hemodialysis patients were included in the analysis. The three most important outcomes were safety of treatment, health-related quality of life, and satisfaction with care. Further important outcomes were hospital stays, accompanying symptoms, hemodialysis duration, and the improvement or preservation of a good emotional state. Age, profession, and education had the strongest influence on relevant differences of preferences for outcomes; no relevant influence of sex or comorbidity was observed.Conclusion: Outcomes concerning the delivery or provision of care and aspects influencing quality of life are rated by patients to be at least as important as clinical outcomes. Many of the outcomes judged to be important by the patients are not regularly considered in research, evaluation studies, or quality programs. Keywords: patient-centered outcomes, preference elicitation, chronic disease, patient-centered research, rating scal

    Transcriptional Heterogeneity of IgM<sup>+</sup> Cells in Rainbow Trout (<i>Oncorhynchus mykiss</i>) Tissues

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    <div><p>Two major classes of B lymphocytes have been described to date in rainbow trout: IgM<sup>+</sup> and IgT<sup>+</sup> cells. IgM<sup>+</sup> cells are mainly localized in the spleen, peripheral blood and kidney but are also found in other tissues. However, differences among IgM<sup>+</sup> cell populations attending to its location are poorly defined in fish. Thus, the aim of this work was to characterize the expression of different immune molecules such as chemokine receptors, Toll-like receptors (TLRs) and transcription factors on sorted IgM<sup>+</sup> lymphocytes from different rainbow trout tissues. IgM<sup>+</sup> populations from blood, spleen, kidney, gills, intestine and liver were isolated by cell sorting and the constitutive levels of transcription of these genes evaluated by real-time PCR. To further characterize B cells, we identified an MS4A sequence. In humans, the MS4A family includes several genes with immune functions, such as the B cell marker CD20 or FcRβ. Subsequently, we have also evaluated the mRNA levels of this MS4A gene in the different IgM<sup>+</sup> populations. The relevant differences in transcriptional patterns observed for each of these IgM<sup>+</sup> populations analyzed, point to the presence of functionally different tissue-specific B cell populations in rainbow trout. The data shown provides a pattern of genes transcribed in IgM<sup>+</sup> B cells not previously revealed in teleost fish. Furthermore, the constitutive expression of all the TLR genes analyzed in IgM<sup>+</sup> cells suggests an important role for these cells in innate immunity.</p> </div
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