2,870 research outputs found

    Numerical description of discharge characteristics of the plasma needle

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    The plasma needle is a small atmospheric, nonthermal, radio-frequency discharge, generated at the tip of a needle, which can be used for localized disinfection of biological tissues. Although several experiments have characterized various qualities of the plasma needle, discharge characteristics and electrical properties are still not well known. In order to provide initial estimates on electrical properties and quantities such as particle densities, we employed a two-dimensional, time-dependent fluid model to describe the plasma needle. In this model the balance equation is solved in the drift-diffusion approach for various species and the electron energy, as well as Poisson's equation. We found that the plasma production occurs in the sheath region and results in a steady flux of reactive species outwards. Even at small (< 0.1%) admixtures of N-2 to the He background, N-2(+) is the dominant ion. The electron density is typically 10(11) cm(-3) and the dissipated power is in the order of 10 mW. These results are consistent with the experimental data available and can give direction to the practical development of the plasma needle. (c) 2005 American Institute of Physics

    Effects of selective breeding for increased wheel-running behavior on circadian timing of substrate oxidation and ingestive behavior

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    Fluctuations in substrate preference and utilization across the circadian cycle may be influenced by the degree of physical activity and nutritional status. In the present study, we assessed these relationships in control mice and in mice from a line selectively bred for high voluntary wheel-running behavior, either when feeding a carbohydrate-rich/low-fat (LF) or a high-fat (HF) diet. Housed without wheels, selected mice, and in particular the females, exhibited higher cage activity than their non-selected controls during the dark phase and at the onset of the light phase, irrespective of diet. This was associated with increases in energy expenditure in both sexes of the selection line. In selected males, carbohydrate oxidation appeared to be increased compared to controls. In contrast, selected females had profound increases in fat oxidation above the levels in control females to cover the increased energy expenditure during the dark phase. This is remarkable in light of the finding that the selected mice, and in particular the females showed higher preference for the LF diet relative to controls. It is likely that hormonal and/or metabolic signals increase carbohydrate preference in the selected females, which may serve optimal maintenance of cellular metabolism in the presence of augmented fat oxidation. (C) 2010 Elsevier Inc. All rights reserved

    Structural insight into African horsesickness virus infection

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    African horsesickness (AHS) is a devastating disease of horses. The disease is caused by the double-stranded RNA-containing African horsesickness virus (AHSV). Using electron cryomicroscopy and three-dimensional image reconstruction, we determined the architecture of an AHSV serotype 4 (AHSV-4) reference strain. The structure revealed triple-layered AHS virions enclosing the segmented genome and transcriptase complex. The innermost protein layer contains 120 copies of VP3, with the viral polymerase, capping enzyme, and helicase attached to the inner surface of the VP3 layer on the 5-fold axis, surrounded by double-stranded RNA. VP7 trimers form a second, T 13 layer on top of VP3. Comparative analyses of the structures of bluetongue virus and AHSV-4 confirmed that VP5 trimers form globular domains and VP2 trimers form triskelions, on the virion surface. We also identified an AHSV-7 strain with a truncated VP2 protein (AHSV-7 tVP2) which outgrows AHSV-4 in culture. Comparison of AHSV-7 tVP2 to bluetongue virus and AHSV-4 allowed mapping of two domains in AHSV-4 VP2, and one in bluetongue virus VP2, that are important in infection. We also revealed a protein plugging the 5-fold vertices in AHSV-4. These results shed light on virus-host interactions in an economically important orbivirus to help the informed design of new vaccines

    Conservative Treatment in Diverticulitis Patients with Pericolic Extraluminal Air and the Role of Antibiotic Treatment

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    Background: Recently published studies advocate a conservative approach with observation and antibiotic treatment in diverticulitis patients with pericolic air on computed tomography (CT). The primary aim of this study was to assess the clinical course of initially conservatively treated diverticulitis patients with isolated pericolic air and to identify risk factors for conservative treatment failure. The secondary aim was to assess the outcome of non-antibiotic treatment. Methods: Patient data from a retrospective cohort study on risk factors for complicated diverticulitis were combined with data from the DIABOLO trial, a randomised controlled trial comparing non-antibiotic with antibiotic treatment in patients with uncomplicated diverticulitis. The present study identified all patients with Hinchey 1A diverticulitis with isolated pericolic air on CT. Pericolic air was defined as air located < 5 cm from the affected segment of colon. The primary outcome was failure of conservative management which was defined as need for percutaneous abscess drainage or emergency surgery within 30 days after presentation. A multivariable logistic regression of clinical, radiological and laboratorial parameters with respect to treatment failure was performed. Results: A total of 109 patients were included in the study. Fifty-two (48%) patients were treated with antibiotics. Nine (8%) patients failed conservative management, seven (13%) in the antibiotic treatment group and two (4%) in the non-antibiotic group (p = 0.083). Only (increased) CRP level at presentation was an independent predictor for treatment failure. Conclusions: Conservative treatment in diverticulitis patients with isolated pericolic air is a suitable treatment strategy. Moreover, non-antibiotic treatment might be reasonable in selected patients

    The Natural Sequence in Which Subclinical Inflamed Joint Tissues Subside or Progress to Rheumatoid Arthritis:A Study of Serial MRIs in the TREAT EARLIER Trial

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    Objective: The natural trajectory of clinical arthritis progression at the tissue level remains elusive. We hypothesized that subclinical inflammation in different joint tissues (synovitis, tenosynovitis, osteitis) increases in a distinct temporal order in patients with clinically suspect arthralgia (CSA) who develop rheumatoid arthritis (RA) and subsides in a different sequence when CSA spontaneously resolves. Methods: We studied 185 serial magnetic resonance images (MRIs) from CSA patients with subclinical joint inflammation from the placebo arm of the TREAT EARLIER trial: 52 MRIs from 21 RA progressors (MRIs conducted at 1 year before, at 4 months before, and upon RA development), and 133 MRIs from 35 patients with spontaneous resolution of pain (MRIs conducted at baseline and at 4, 12, and 24 months). MRIs were scored for osteitis, synovitis, and tenosynovitis. We used cross-lagged models to evaluate 2 types of time patterns between pairs of inflamed tissues: a simultaneous pattern (coinciding changes) and a subsequent pattern (inflammatory changes in 1 tissue preceding changes in another tissue). Results:In patients who developed RA, synovitis, tenosynovitis, and osteitis increased simultaneously. Increasing osteitis occurred in the final 4 months before RA diagnosis, following incremental tenosynovitis and synovitis changes during the 1 year to 4 months before diagnosis (P &lt; 0.01). In anti–citrullinated protein antibody (ACPA)-positive and ACPA-negative patients who progressed to RA, osteitis increased just before RA development. In patients with pain resolution, simultaneous decreases in synovitis, tenosynovitis, and osteitis occurred, with tenosynovitis decreasing in the first 4 months after CSA onset preceding decreasing synovitis and osteitis during 4–12 months (P = 0.02 and P &lt; 0.01). Conclusion:We identified natural sequences of subclinical inflammation in different joint tissues, which deepens our understanding of clinical arthritis and RA development. During RA progression, increasing osteitis followed previous increases in tenosynovitis and synovitis. During pain resolution, tenosynovitis decreased first, followed by decreasing synovitis and osteitis.</p

    Transcription Factor STOX1A Promotes Mitotic Entry by Binding to the CCNB1 Promotor

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    Background: In this study we investigated the involvement of the transcription factor STOX1A in the regulation of the cell cycle. Methodology/Principal Findings: We found that several major cell cycle regulatory genes were differentially expressed upon STOX1A stimulation and knockdown in the neuroblastoma cell line SH-SY5Y. This includes STOX1A dependent differential regulation of cyclin B1 expression, a cyclin which is known to regulate mitotic entry during the cell cycle. The differential regulation of cyclin B1 expression by STOX1A is direct as shown with chromatin immunoprecipitation. Results furthermore suggest that mitotic entry is enhanced through the direct upregulation of cyclin B1 expression effectuated b

    Study on intracranial meningioma using PET ligand investigation during follow-up over years (SIMPLIFY)

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    Purpose Radiologic follow-up of patients with a meningioma at the skull base or near the venous sinuses with magnetic resonance imaging (MRI) after stereotactic radiotherapy (SRT) and neurosurgical resection(s) can be difficult to interpret. This study evaluates the addition of C-11-methionine positron emission tomography (MET-PET) to the regular MRI follow-up. Methods This prospective pilot study included patients with predominantly WHO grade I meningiomas at the skull base or near large vascular structures. Previous SRT was part of their oncological treatment. A MET-PET in adjunct to their regular MRI follow-up was performed. The standardized uptake value (SUV) was determined for the tumor and the healthy brain, on the pre-SRT target delineation MET-PET and the follow-up MET-PET. Tumor-to-normal ratios were calculated, and C-11-methionine uptake over time was analyzed. Agreement between the combined MRI/MET-PET report and the MRI-only report was determined using Cohen's kappa. Results Twenty patients with stable disease underwent an additional MET-PET, with a median follow-up of 84 months after SRT. Post-SRT SUV T/N ratios ranged between 2.16 and 3.17. When comparing the pre-SRT and the post-SRT MET-PET, five categories of SUV T/N ratios did not change significantly. Only the SUVpeak T/N-cortex decreased significantly from 2.57 (SD 1.02) to 2.20 (SD 0.87) [p = 0.004]. A kappa of 0.77 was found, when comparing the MRI/MET-PET report to the MRI-only report, indicating no major change in interpretation of follow-up data. Conclusion In this pilot study, C-11-methionine uptake remained remarkably high in meningiomas with long-term follow-up after SRT. Adding MET-PET to the regular MRI follow-up had no impact on the interpretation of follow-up imaging

    Representations of Chinese gendered and racialised bodies in contemporary media sites

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    Social media are influential sociocultural forces that construct and transmit information about gender, health and bodies to young people in the digital age. In health and physical activity, Chinese people are often represented and positioned differently to other (minority) ethnic groups. For example, Black young people are often understood as having low academic motivations and aspirations but as ‘natural’ athletes; in contrast, Chinese young people, seen as the ‘model minority’ who excel in STEM subjects, are fragile, reserved and disinterested in physical movements. These public forms of representation may sit in opposition to the young people’s embodied identity. When these misrepresentations are internalised, issues such as micro-aggression and racism may have an impact on Chinese young people’s health and wellbeing. This paper aims to examine how Chinese bodies are gendered and racialised in contemporary social media sites (e.g. Google News, LiveJournal, Medium, Wordpress). Drawing on critical discourse analysis and Foucault’s concepts of normalisation and discursive practice, the paper will problematise the often taken-for-granted gendered and racialised stereotypes related to Chinese physicality and health on social media sites. Implications for developing future research and teaching resources in critical media health literacy for young people on issues related to gender and equity will be provided. The results affect how we understand, represent, and discuss Chinese (young) people on social media sites, thereby how Chinese young people engage, construct, and perform their embodied identities in Western, English speaking societies
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