123 research outputs found

    Quantum optics measurement scheme for quantum geometry and topological invariants

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    We show how a quantum optical measurement scheme based on heterodyne detection can be used to explore geometrical and topological properties of condensed matter systems. Considering a 2D material placed in a cavity with a coupling to the environment, we compute correlation functions of the photons exiting the cavity and relate them to the hybrid light-matter state within the cavity. Different polarizations of the intracavity field give access to all components of the quantum geometric tensor on contours in the Brillouin zone defined by the transition energy. Combining recent results based on the metric-curvature correspondence with the measured quantum metric allows us to characterize the topological phase of the material. Moreover, in systems where SzS_z is a good quantum number, the procedure also allows us to extract the spin Chern number. As an interesting application, we consider a minimal model for twisted bilayer graphene at the magic angle, and discuss the feasibility of extracting the Euler number.Comment: 16 pages, 4 figure

    (S S,2S,3R)-2-(2-Methyl­propane-2-sulfin­amido)-3-phenyl­butyronitrile

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    The absolute configuration has been determined for the title compound, C14H20N2OS. Inter­molecular N—H⋯O hydrogen bonds are observed in the crystal packing, forming infinitive one-dimensional chains with the base vector [100]

    evolution, structure and function of metazoan splicing factor PRPF39

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    In the yeast U1 snRNP the Prp39/Prp42 heterodimer is essential for early steps of spliceosome assembly. In metazoans no Prp42 ortholog exists, raising the question how the heterodimer is functionally substituted. Here we present the crystal structure of murine PRPF39, which forms a homodimer. Structure-guided point mutations disrupt dimer formation and inhibit splicing, manifesting the homodimer as functional unit. PRPF39 expression is controlled by NMD-inducing alternative splicing in mice and human, suggesting a role in adapting splicing efficiency to cell type specific requirements. A phylogenetic analysis reveals coevolution of shortened U1 snRNA and the absence of Prp42, which correlates with overall splicing complexity in different fungi. While current models correlate the diversity of spliceosomal proteins with splicing complexity, our study highlights a contrary case. We find that organisms with higher splicing complexity have substituted the Prp39/Prp42 heterodimer with a PRPF39 homodimer

    Interactive optimization for the planning of urban systems

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    This paper introduces urb.io, an interactive optimization framework for early-stage urban planning. It allows urban planners to generate and explore many alternative urban configurations, while focusing their attention on the most promising ones. First, addressing the need for integrated urban modeling approaches, a Mixed Integer Linear Programing (MILP) optimization model representing both urban and energy system components was developed. Second, an interface based on parallel coordinates and georeferenced maps is proposed to effectively communicate the optimization results to decision makers, revealing tradeoffs and synergies between competing objectives. Interaction with the parallel coordinates charts further allows planners to steer consec- utive optimization runs based on their preferences and experience. The framework is applied to an urban development project in Switzerland to demonstrate its usability and relevance

    Interactive Optimization With Parallel Coordinates: Exploring Multidimensional Spaces for Decision Support

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    Interactive optimization methods are particularly suited for letting human decision makers learn about a problem, while a computer learns about their preferences to generate relevant solutions. For interactive optimization methods to be adopted in practice, computational frameworks are required, which can handle and visualize many objectives simultaneously, provide optimal solutions quickly and representatively, all while remaining simple and intuitive to use and understand by practitioners. Addressing these issues, this work introduces SAGESSE (Systematic Analysis, Generation, Exploration, Steering and Synthesis Experience), a decision support methodology, which relies on interactive multiobjective optimization. Its innovative aspects reside in the combination of (i) parallel coordinates as a means to simultaneously explore and steer the underlying alternative generation process, (ii) a Sobol sequence to efficiently sample the points to explore in the objective space, and (iii) on-the-fly application of multiattribute decision analysis, cluster analysis and other data visualization techniques linked to the parallel coordinates. An illustrative example demonstrates the applicability of the methodology to a large, complex urban planning problem

    Intra- and inter-fraction breath-hold variations and margins for radiotherapy of abdominal targets

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    Radiotherapy in expiration breath-hold (EBH) has the potential to reduce treatment volumes of abdominal targets compared to an internal target volume concept in free-breathing. The reproducibility of EBH and required safety margins were investigated to quantify this volumetric benefit. Pre- and post-treatment diaphragm position difference and the positioning variability were determined on computed tomography. Systematic and random errors for EBH position reproducibility and positioning variability were calculated, resulting in margins of 7 to 12 mm depending on the prescription isodose and fractionation. A reduced volume was shown for EBH for lesions with superior-inferior breathing motion above 4 to 8 mm

    The underestimated burden of monogenic kidney disease in adults waitlisted for kidney transplantation

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    Purpose: Chronic kidney disease (CKD) is a major health-care burden. Increasing evidence suggests that a considerable proportion of patients are affected by a monogenic kidney disorder. Methods: In this study, the kidney transplantation waiting list at the Charité was screened for patients with undetermined cause of CKD. By next-generation sequencing (NGS) we targeted all 600 genes described and associated with kidney disease or allied disorders. Results: In total, 635 patients were investigated. Of these, 245 individuals had a known cause of CKD (38.5%) of which 119 had a proven genetic disease (e.g., ADPKD, Alport). The other 340 patients (53.5%) were classified as undetermined diagnosis, of whom 87 had kidney failure (KF) onset <40 years. To this latter group genetic testing was offered as well as to those patients (n = 29) with focal segmental glomerulosclerosis (FSGS) and all individuals (n = 21) suspicious for thrombotic microangiopathy (TMA) in kidney biopsy. We detected diagnostic variants in 26 of 126 patients (20.6%) of which 14 of 126 (11.1%) were pathogenic or likely pathogenic. In another 12 of 126 (9.5%) patients, variants of unknown significance (VUS) were detected. Conclusion: Our study demonstrates the diagnostic value of comprehensive genetic testing among patients with undetermined CKD

    Interleukin-7 Links T Lymphocyte and Intestinal Epithelial Cell Homeostasis

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    Interleukin-7 (IL-7) is a major survival factor for mature T cells. Therefore, the degree of IL-7 availability determines the size of the peripheral T cell pool and regulates T cell homeostasis. Here we provide evidence that IL-7 also regulates the homeostasis of intestinal epithelial cells (IEC), colon function and the composition of the commensal microflora. In the colon of T cell-deficient, lymphopenic mice, IL-7-producing IEC accumulate. IEC hyperplasia can be blocked by IL-7-consuming T cells or the inactivation of the IL-7/IL-7R signaling pathway. However, the blockade of the IL-7/IL-7R signaling pathway renders T cell-deficient mice more sensitive to chemically-induced IEC damage and subsequent colitis. In summary, our data demonstrate that IL-7 promotes IEC hyperplasia under lymphopenic conditions. Under non-lymphopenic conditions, however, T cells consume IL-7 thereby limiting IEC expansion and survival. Hence, the degree of IL-7 availability regulates both, T cell and IEC homeostasis

    Comprehensive Antigen Screening Identifies Moraxella catarrhalis Proteins That Induce Protection in a Mouse Pulmonary Clearance Model

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    Moraxella catarrhalis is one of the three most common causative bacterial pathogens of otitis media, however no effective vaccine against M. catarrhalis has been developed so far. To identify M. catarrhalis vaccine candidate antigens, we used carefully selected sera from children with otitis media and healthy individuals to screen small-fragment genomic libraries that are expressed to display frame-selected peptides on a bacterial cell surface. This ANTIGENome technology led to the identification of 214 antigens, 23 of which were selected by in vitro or in vivo studies for additional characterization. Eight of the 23 candidates were tested in a Moraxella mouse pulmonary clearance model, and 3 of these antigens induced significantly faster bacterial clearance compared to adjuvant or to the previously characterized antigen OmpCD. The most significant protection data were obtained with the antigen MCR_1416 (Msp22), which was further investigated for its biological function by in vitro studies suggesting that Msp22 is a heme binding protein. This study comprises one of the most exhaustive studies to identify potential vaccine candidate antigens against the bacterial pathogen M. catarrhalis
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