480 research outputs found

    Electron beam pinch

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    One of the major objects of current plasma pinch research is an understanding of turbulence and its effects in enhanced diffusion rates within a pinch. As an approach to this problem, the electron beam pinch was conceived. In this experiment, an electron beam (400 kev, 0.1 amp, 0.1 usee, duration) enters a linear pinch at one electrode and is observed (by light from a phosphor screen) at the opposite pinch electrode. By a selection of radial positions and time of injection, the turbulent pinch configuration may be explored. Use of a probe with such small mass (as beam of electrons) may yield important information on turbulent diffusion. This report presents the results of preliminary tests and the first effort to obtain parameter dependence of the pinch configuration so that the electron beam may be properly programmed. All runs wore made at a pinch current of 200,000 amp which, from previous experience, was assumed to be a good medium value. Initial gas pressures were varied from 25 to 400 microns of deuterium and initial z-field varied from 500 to 2000 gauss. Analysis of all runs show that pressure from particles boiled off the wall dominated over any other pressur distribution. Even for field configurations which show very little turbulence, the pressure at the wall is overpowering. Pressure distribution is improved by impressing a reversed axial field and by reducing the magnitude of the pinch current.http://www.archive.org/details/electronbeampinc00hortLieutenant, United States NavyApproved for public release; distribution is unlimited

    Modulation of FAK and Src adhesion signaling occurs independently of adhesion complex composition

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    Integrin adhesion complexes (IACs) form mechanochemical connections between the extracellular matrix and actin cytoskeleton and mediate phenotypic responses via posttranslational modifications. Here, we investigate the modularity and robustness of the IAC network to pharmacological perturbation of the key IAC signaling components focal adhesion kinase (FAK) and Src. FAK inhibition using AZ13256675 blocked FAK(Y397) phosphorylation but did not alter IAC composition, as reported by mass spectrometry. IAC composition was also insensitive to Src inhibition using AZD0530 alone or in combination with FAK inhibition. In contrast, kinase inhibition substantially reduced phosphorylation within IACs, cell migration and proliferation. Furthermore using fluorescence recovery after photobleaching, we found that FAK inhibition increased the exchange rate of a phosphotyrosine (pY) reporter (dSH2) at IACs. These data demonstrate that kinase-dependent signal propagation through IACs is independent of gross changes in IAC composition. Together, these findings demonstrate a general separation between the composition of IACs and their ability to relay pY-dependent signals

    Longitudinal landscapes of serum antibody repertoires after influenza infection and vaccination

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    Vaccination is the most effective means of infectious disease prevention. Despite its success, however, we still lack a clear understanding of vaccine responses in humans. For example, influenza vaccines still leave a large fraction of population vulnerable. Over the past decade, single B-cell analysis and next-generation sequencing (NGS) technologies have become invaluable tools for studying the antibody repertoire to influenza. Such studies have led to discoveries of broadly-neutralizing antibodies (bNAbs), which can neutralize across multiple strains of influenza virus, promoting the notion of designing a universal vaccine that will elicit such antibodies. One of such isolated bNAbs, called FI6, showed remarkable ability to neutralize all of the influenza A virus strains through targeting the conserved epitope in the stem of hemagglutinin (HA). However, it remains unclear whether such bNAbs actually play a role in conferring protection against influenza since antibody proteins (not B-cells) need to circulate at physiologically relevant concentrations in serum to have implications in protection. Using high-resolution proteomics coupled with NGS, we quantitatively determined the serological antibody repertoire to CA09 HA (H1) at the individual clonotype-level in a donor (whom FI6 was isolated from) following influenza infection (in 2010 with pandemic CA09) and vaccination across five years (2010-2014 with seasonal flu vaccine). We analyzed the temporal changes of head-targeting and stem-binding antibodies, illustrating the gradual increase of stem-targeting antibodies following repeated exposures to CA09 HA. Following vaccination in 2014, \u3e60% of the repertoire consisted of one single clonotype of stem-binding antibody that was present at very low abundance in 2010. Our data demonstrate that the repetitive exposure to influenza skews the serological repertoire toward antibodies that target conserved epitopes, and these antibodies continue to be boosted every time the same epitopes are encountered. Once elicited, stem-binding antibodies displayed a tendency to persist in serum across multiple years while head-specific antibodies decayed quicker. The differential longevity of stem-binding and head-specific antibodies presented here has direct implications for the design of the future universal vaccine

    Metabolic syndrome components and their response to lifestyle and metformin interventions are associated with differences in diabetes risk in persons with impaired glucose tolerance

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    Aims To determine the association of metabolic syndrome (MetS) and its components with diabetes risk in participants with impaired glucose tolerance (IGT), and whether intervention-related changes in MetS lead to differences in diabetes incidence. Methods We used the National Cholesterol Education Program/Adult Treatment Panel III (NCEP/ATP III) revised MetS definition at baseline and intervention-related changes of its components to predict incident diabetes using Cox models in 3234 Diabetes Prevention Program (DPP) participants with IGT over an average follow-up of 3.2 years. Results In an intention-to-treat analysis, the demographic-adjusted hazard ratios (95% confidence interval) for diabetes in those with MetS (vs. no MetS) at baseline were 1.7 (1.3–2.3), 1.7 (1.2–2.3) and 2.0 (1.3–3.0) for placebo, metformin and lifestyle groups, respectively. Higher levels of fasting plasma glucose and triglycerides at baseline were independently associated with increased risk of diabetes. Greater waist circumference (WC) was associated with higher risk in placebo and lifestyle groups, but not in the metformin group. In a multivariate model, favourable changes in WC (placebo and lifestyle) and high-density lipoprotein cholesterol (placebo and metformin) contributed to reduced diabetes risk. Conclusions MetS and some of its components are associated with increased diabetes incidence in persons with IGT in a manner that differed according to DPP intervention. After hyperglycaemia, the most predictive factors for diabetes were baseline hypertriglyceridaemia and both baseline and lifestyle-associated changes in WC. Targeting these cardiometabolic risk factors may help to assess the benefits of interventions that reduce diabetes incidence

    Opposing Effects of Particle Pollution, Ozone, and Ambient Temperature on Arterial Blood Pressure

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    Background: Diabetes increases the risk of hypertension and orthostatic hypotension and raises the risk of cardiovascular death during heat waves and high pollution episodes
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