601 research outputs found
Software-Reconfigurable Processors for Spacecraft
A report presents an overview of an architecture for a software-reconfigurable network data processor for a spacecraft engaged in scientific exploration. When executed on suitable electronic hardware, the software performs the functions of a physical layer (in effect, acts as a software radio in that it performs modulation, demodulation, pulse-shaping, error correction, coding, and decoding), a data-link layer, a network layer, a transport layer, and application-layer processing of scientific data. The software-reconfigurable network processor is undergoing development to enable rapid prototyping and rapid implementation of communication, navigation, and scientific signal-processing functions; to provide a long-lived communication infrastructure; and to provide greatly improved scientific-instrumentation and scientific-data-processing functions by enabling science-driven in-flight reconfiguration of computing resources devoted to these functions. This development is an extension of terrestrial radio and network developments (e.g., in the cellular-telephone industry) implemented in software running on such hardware as field-programmable gate arrays, digital signal processors, traditional digital circuits, and mixed-signal application-specific integrated circuits (ASICs)
Risk-Stratified Screening for Colorectal Cancer Using Genetic and Environmental Risk Factors:A Cost-Effectiveness Analysis Based on Real-World Data
Background & Aims: Previous studies on the cost-effectiveness of personalized colorectal cancer (CRC) screening were based on hypothetical performance of CRC risk prediction and did not consider the association with competing causes of death. In this study, we estimated the cost-effectiveness of risk-stratified screening using real-world data for CRC risk and competing causes of death. Methods: Risk predictions for CRC and competing causes of death from a large community-based cohort were used to stratify individuals into risk groups. A microsimulation model was used to optimize colonoscopy screening for each risk group by varying the start age (40–60 years), end age (70–85 years), and screening interval (5–15 years). The outcomes included personalized screening ages and intervals and cost-effectiveness compared with uniform colonoscopy screening (ages 45–75, every 10 years). Key assumptions were varied in sensitivity analyses. Results: Risk-stratified screening resulted in substantially different screening recommendations, ranging from a one-time colonoscopy at age 60 for low-risk individuals to a colonoscopy every 5 years from ages 40 to 85 for high-risk individuals. Nevertheless, on a population level, risk-stratified screening would increase net quality-adjusted life years gained (QALYG) by only 0.7% at equal costs to uniform screening or reduce average costs by 1.2% for equal QALYG. The benefit of risk-stratified screening improved when it was assumed to increase participation or costs less per genetic test. Conclusions: Personalized screening for CRC, accounting for competing causes of death risk, could result in highly tailored individual screening programs. However, average improvements across the population in QALYG and cost-effectiveness compared with uniform screening are small.</p
Viscosity and Diffusion: Crowding and Salt Effects in Protein Solutions
We report on a joint experimental-theoretical study of collective diffusion
in, and static shear viscosity of solutions of bovine serum albumin (BSA)
proteins, focusing on the dependence on protein and salt concentration. Data
obtained from dynamic light scattering and rheometric measurements are compared
to theoretical calculations based on an analytically treatable spheroid model
of BSA with isotropic screened Coulomb plus hard-sphere interactions. The only
input to the dynamics calculations is the static structure factor obtained from
a consistent theoretical fit to a concentration series of small-angle X-ray
scattering (SAXS) data. This fit is based on an integral equation scheme that
combines high accuracy with low computational cost. All experimentally probed
dynamic and static properties are reproduced theoretically with an at least
semi-quantitative accuracy. For lower protein concentration and low salinity,
both theory and experiment show a maximum in the reduced viscosity, caused by
the electrostatic repulsion of proteins. The validity range of a generalized
Stokes-Einstein (GSE) relation connecting viscosity, collective diffusion
coefficient, and osmotic compressibility, proposed by Kholodenko and Douglas
[PRE 51, 1081 (1995)] is examined. Significant violation of the GSE relation is
found, both in experimental data and in theoretical models, in semi-dilute
systems at physiological salinity, and under low-salt conditions for arbitrary
protein concentrations
Prion Uptake in the Gut: Identification of the First Uptake and Replication Sites
After oral exposure, prions are thought to enter Peyer's patches via M cells and accumulate first upon follicular dendritic cells (FDCs) before spreading to the nervous system. How prions are actually initially acquired from the gut lumen is not known. Using high-resolution immunofluorescence and cryo-immunogold electron microscopy, we report the trafficking of the prion protein (PrP) toward Peyer's patches of wild-type and PrP-deficient mice. PrP was transiently detectable at 1 day post feeding (dpf) within large multivesicular LAMP1-positive endosomes of enterocytes in the follicle-associated epithelium (FAE) and at much lower levels within M cells. Subsequently, PrP was detected on vesicles in the late endosomal compartments of macrophages in the subepithelial dome. At 7–21 dpf, increased PrP labelling was observed on the plasma membranes of FDCs in germinal centres of Peyer's patches from wild-type mice only, identifying FDCs as the first sites of PrP conversion and replication. Detection of PrP on extracellular vesicles displaying FAE enterocyte-derived A33 protein implied transport towards FDCs in association with FAE-derived vesicles. By 21 dpf, PrP was observed on the plasma membranes of neurons within neighbouring myenteric plexi. Together, these data identify a novel potential M cell-independent mechanism for prion transport, mediated by FAE enterocytes, which acts to initiate conversion and replication upon FDCs and subsequent infection of enteric nerves
One-year outcomes of the ARTISAN-SNM study with the Axonics System for the treatment of urinary urgency incontinence
Aims: Sacral neuromodulation (SNM) is a guideline-recommended treatment for voiding dysfunction including urgency, urge incontinence, and nonobstructive retention as well
The twilight of the Liberal Social Contract? On the Reception of Rawlsian Political Liberalism
This chapter discusses the Rawlsian project of public reason, or public justification-based 'political' liberalism, and its reception. After a brief philosophical rather than philological reconstruction of the project, the chapter revolves around a distinction between idealist and realist responses to it. Focusing on political liberalism’s critical reception illuminates an overarching question: was Rawls’s revival of a contractualist approach to liberal legitimacy a fruitful move for liberalism and/or the social contract tradition? The last section contains a largely negative answer to that question. Nonetheless the chapter's conclusion shows that the research programme of political liberalism provided and continues to provide illuminating insights into the limitations of liberal contractualism, especially under conditions of persistent and radical diversity. The programme is, however, less receptive to challenges to do with the relative decline of the power of modern states
Progress toward the prevention and treatment of atrial fibrillation: A summary of the Heart Rhythm Society Research Forum on the Treatment and Prevention of Atrial Fibrillation, Washington, DC, December 9–10, 2013.
Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization.
The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD
Casein kinase 1 delta functions at the centrosome to mediate Wnt-3a–dependent neurite outgrowth
Centrosomal localization of kinase-active CK1δ is required for neurite outgrowth in response to Wnt-3a
- …