484 research outputs found
Electron beam pinch
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
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
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
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
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Per- and polyfluoroalkyl substances and kidney function: Follow-up results from the Diabetes Prevention Program trial
Per- and polyfluoroalkyl substances (PFAS) are ubiquitously detected in populations worldwide and may hinder kidney function. The objective of the study was to determine longitudinal associations of plasma PFAS concentrations with estimated glomerular filtration rate (eGFR) and evaluate whether a lifestyle intervention modify the associations. We studied 875 participants initially randomized to the lifestyle or placebo arms in the Diabetes Prevention Program (DPP, 1996–2002) trial and Outcomes Study (DPPOS, 2002–2014). We ran generalized linear mixed models accounting a priori covariates to evaluate the associations between baseline PFAS concentrations and repeated measures of eGFR, separately, for six PFAS (PFOS, PFOA, PFHxS, EtFOSAA, MeFOSAA, PFNA); then used quantile-based g-computation to evaluate the effects of the six PFAS chemicals as a mixture. The cohort was 64.9% female; 73.4% 40–64 years-old; 29.4% with hypertension; 50.5% randomized to lifestyle intervention and 49.5% to placebo and had similar plasma PFAS concentrations as the general U.S. population in 1999–2000. Most participants had normal kidney function (eGFR \u3e 90 mL/min/1.73 m2) over the approximately 14 years of follow-up. We found that plasma PFAS concentrations during DPP were inversely associated with eGFR during DPPOS follow-up. Each quartile increase in baseline plasma concentration of the 6 PFAS as a mixture was associated with 2.26 mL/min/1.73 m2 lower eGFR (95% CI: −4.12, −0.39) at DPPOS Year 5, approximately 9 years since DPP randomization and PFAS measurements. The lifestyle intervention did not modify associations, but inverse associations were stronger among participants with hypertension at baseline. Among prediabetic adults, we found inverse associations between baseline plasma PFAS concentrations and measures of eGFR throughout 14 years of follow-up. The lifestyle intervention of diet, exercise and behavioral changes did not modify the associations, but persons with hypertension may have heightened susceptibility
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February 1967 Conference Issue
Massachusetts Turf and Lawn Grass CouncilBetter Turf Through Research and Educatio
Opposing Effects of Particle Pollution, Ozone, and Ambient Temperature on Arterial Blood Pressure
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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