2,764 research outputs found

    A ballistic graphene superconducting microwave circuit

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    Josephson junctions (JJ) are a fundamental component of microwave quantum circuits, such as tunable cavities, qubits and parametric amplifiers. Recently developed encapsulated graphene JJs, with supercurrents extending over micron distance scales, have exciting potential applications as a new building block for quantum circuits. Despite this, the microwave performance of this technology has not been explored. Here, we demonstrate a microwave circuit based on a ballistic graphene JJ embedded in a superconducting cavity. We directly observe a gate-tunable Josephson inductance through the resonance frequency of the device and, using a detailed RF model, we extract this inductance quantitatively. We also observe the microwave losses of the device, and translate this into sub-gap resistances of the junction at {\mu}eV energy scales, not accessible in DC measurements. The microwave performance we observe here suggests that graphene Josephson junctions are a feasible platform for implementing coherent quantum circuits.Comment: 43 pages, 20 figure

    Mechanical Competence and Bone Quality Develop During Skeletal Growth.

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    Bone fracture risk is influenced by bone quality, which encompasses bone's composition as well as its multiscale organization and architecture. Aging and disease deteriorate bone quality, leading to reduced mechanical properties and higher fracture incidence. Largely unexplored is how bone quality and mechanical competence progress during longitudinal bone growth. Human femoral cortical bone was acquired from fetal (n = 1), infantile (n = 3), and 2- to 14-year-old cases (n = 4) at the mid-diaphysis. Bone quality was assessed in terms of bone structure, osteocyte characteristics, mineralization, and collagen orientation. The mechanical properties were investigated by measuring tensile deformation at multiple length scales via synchrotron X-ray diffraction. We find dramatic differences in mechanical resistance with age. Specifically, cortical bone in 2- to 14-year-old cases exhibits a 160% greater stiffness and 83% higher strength than fetal/infantile cases. The higher mechanical resistance of the 2- to 14-year-old cases is associated with advantageous bone quality, specifically higher bone volume fraction, better micronscale organization (woven versus lamellar), and higher mean mineralization compared with fetal/infantile cases. Our study reveals that bone quality is superior after remodeling/modeling processes convert the primary woven bone structure to lamellar bone. In this cohort of female children, the microstructural differences at the femoral diaphysis were apparent between the 1- to 2-year-old cases. Indeed, the lamellar bone in 2- to 14-year-old cases had a superior structural organization (collagen and osteocyte characteristics) and composition for resisting deformation and fracture than fetal/infantile bone. Mechanistically, the changes in bone quality during longitudinal bone growth lead to higher fracture resistance because collagen fibrils are better aligned to resist tensile forces, while elevated mean mineralization reinforces the collagen scaffold. Thus, our results reveal inherent weaknesses of the fetal/infantile skeleton signifying its inferior bone quality. These results have implications for pediatric fracture risk, as bone produced at ossification centers during children's longitudinal bone growth could display similarly weak points. © 2019 American Society for Bone and Mineral Research

    Olfactory and Gustatory Dysfunction in Patients With Autoimmune Encephalitis

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    Objective: To test the hypothesis that olfactory (OF) and gustatory function (GF) is disturbed in patients with autoimmune encephalitides (AE).Methods: The orthonasal OF was tested in 32 patients with AE and 32 age- and sex-matched healthy controls (HC) with the standardized Threshold Discrimination Identification (TDI) score. This validated olfactory testing method yields individual scores for olfactory threshold (T), odor discrimination (D), and identification (I), along with a composite TDI score. The GF was determined by the Taste Strip Test (TST).Results: Overall, 24/32 (75%) of patients with AE, but none of 32 HC (p < 0.001) had olfactory dysfunction in TDI testing. The results of the threshold, discrimination and identification subtests were significantly reduced in patients with AE compared to HC (all p < 0.001). Assessed by TST, 5/19 (26.3%) of patients with AE, but none of 19 HC presented a significant limitation in GF (p < 0.001). The TDI score was correlated with the subjective estimation of the olfactory capacity on a visual analog scale (VAS; rs = 0.475, p = 0.008). Neither age, sex, modified Rankin Scale nor disease duration were associated with the composite TDI score.Conclusions: This is the first study investigating OF and GF in AE patients. According to unblinded assessment, patients with AE have a reduced olfactory and gustatory capacity compared to HC, suggesting that olfactory and gustatory dysfunction are hitherto unrecognized symptoms in AE. Further studies with larger number of AE patients would be of interest to verify our results

    Relaxation and edge reconstruction in integer quantum Hall systems

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    The interplay between the confinement potential and electron-electron interactions causes reconstructions of Quantum Hall edges. We study the consequences of this edge reconstruction for the relaxation of hot electrons injected into integer quantum Hall edge states. In translationally invariant edges, the relaxation of hot electrons is governed by three-body collisions which are sensitive to the electron dispersion and thus to reconstruction effects. We show that the relaxation rates are significantly altered in different reconstruction scenarios.Comment: 8 pages, 3 figure

    Directed Gradients in the Excited-State Energy Landscape of Poly(3-hexylthiophene) Nanofibers

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    Funneling excitation energy toward lower energy excited states is a key concept in photosynthesis, which is often realized with at most two chemically different types of pigment molecules. However, current synthetic approaches to establish energy funnels, or gradients, typically rely on Förster-type energy-transfer cascades along many chemically different molecules. Here, we demonstrate an elegant concept for a gradient in the excited-state energy landscape along micrometer-long supramolecular nanofibers based on the conjugated polymer poly(3-hexylthiophene), P3HT, as the single component. Precisely aligned P3HT nanofibers within a supramolecular superstructure are prepared by solution processing involving an efficient supramolecular nucleating agent. Employing hyperspectral imaging, we find that the lowest-energy exciton band edge continuously shifts to lower energies along the nanofibers’ growth direction. We attribute this directed excited-state energy gradient to defect fractionation during nanofiber growth. Our concept provides guidelines for the design of supramolecular structures with an intrinsic energy gradient for nanophotonic applications

    Mapping the landscape of lung cancer breath analysis: A scoping review (ELCABA)

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    Lung cancer is the leading cause of cancer death worldwide due to its late-stage detection. Lung cancer screening, including low-dose computed tomography (low-dose CT), provides an initial clinical solution. Nevertheless, further innovations and refinements would help to alleviate remaining limitations. The non-invasive, gentle, and fast nature of breath analysis (BA) makes this technology highly attractive to supplement low-dose CT for an improved screening algorithm. However, BA has not taken hold in everyday clinical practice. One reason might be the heterogeneity and variety of BA methods. This scoping review is a comprehensive summary of study designs, breath analytical methods, and suggested biomarkers in lung cancer. Furthermore, this synthesis provides a framework with core outcomes for future studies in lung cancer BA. This work supports future research for evidence synthesis, meta-analysis, and translation into clinical routine workflows. Keywords: Biomarker; Breath; Detection; Lung cancer; Scoping review; Screenin

    The Threat of Capital Drain: A Rationale for Public Banks?

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    This paper yields a rationale for why subsidized public banks may be desirable from a regional perspective in a financially integrated economy. We present a model with credit rationing and heterogeneous regions in which public banks prevent a capital drain from poorer to richer regions by subsidizing local depositors, for example, through a public guarantee. Under some conditions, cooperative banks can perform the same function without any subsidization; however, they may be crowded out by public banks. We also discuss the impact of the political structure on the emergence of public banks in a political-economy setting and the role of interregional mobility

    Olfactory and Gustatory Dysfunction in Patients With Autoimmune Encephalitis

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    Objective: To test the hypothesis that olfactory (OF) and gustatory function (GF) is disturbed in patients with autoimmune encephalitides (AE). Methods: The orthonasal OF was tested in 32 patients with AE and 32 age- and sex-matched healthy controls (HC) with the standardized Threshold Discrimination Identification (TDI) score. This validated olfactory testing method yields individual scores for olfactory threshold (T), odor discrimination (D), and identification (I), along with a composite TDI score. The GF was determined by the Taste Strip Test (TST). Results: Overall, 24/32 (75%) of patients with AE, but none of 32 HC (p < 0.001) had olfactory dysfunction in TDI testing. The results of the threshold, discrimination and identification subtests were significantly reduced in patients with AE compared to HC (all p < 0.001). Assessed by TST, 5/19 (26.3%) of patients with AE, but none of 19 HC presented a significant limitation in GF (p < 0.001). The TDI score was correlated with the subjective estimation of the olfactory capacity on a visual analog scale (VAS; r(s) = 0.475, p = 0.008). Neither age, sex, modified Rankin Scale nor disease duration were associated with the composite TDI score. Conclusions: This is the first study investigating OF and GF in AE patients. According to unblinded assessment, patients with AE have a reduced olfactory and gustatory capacity compared to HC, suggesting that olfactory and gustatory dysfunction are hitherto unrecognized symptoms in AE. Further studies with larger number of AE patients would be of interest to verify our results

    Two different binding modes of α-synuclein to lipid vesicles depending on its aggregation state

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    Aggregation of α-synuclein is involved in the pathogenesis of Parkinson's disease (PD). Studies of in vitro aggregation of α-synuclein are rendered complex because of the formation of a heterogeneous population of oligomers. With the use of confocal single-molecule fluorescence techniques, we demonstrate that small aggregates (oligomers) of α-synuclein formed from unbound monomeric species in the presence of organic solvent (DMSO) and iron (Fe 3+) ions have a high affinity to bind to model membranes, regardless of the lipid-composition or membrane curvature. This binding mode contrasts with the well-established membrane binding of α-synuclein monomers, which is accompanied with α-helix formation and requires membranes with high curvature, defects in the lipid packing, and/or negatively charged lipids. Additionally, we demonstrate that membrane-bound α-synuclein monomers are protected from aggregation. Finally, we identified compounds that potently dissolved vesicle-bound α-synuclein oligomers into monomers, leaving the lipid vesicles intact. As it is commonly believed that formation of oligomers is related PD progression, such compounds may provide a promising strategy for the design of novel therapeutic drugs in Parkinson's disease.peer-reviewe
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