403 research outputs found

    Quantitative competitive reverse transcription polymerase chain reaction is not a useful method for quantification of CD4 and CD8 cell status during HIV infection

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    BACKGROUND: A polymerase chain reaction (PCR)-based method for quantitating CD4 and CD8 mRNA could provide a means of assessing immune status of AIDS patients and other immunologically compromised persons without requiring large blood draws, and could be exquisitely sensitive. Such a method would also be useful in assessing the immune status of patients retrospectively. RESULTS: Quantitative competitive reverse transcription PCR (QC-RT-PCR) assays were developed for measurement of CD4 and CD8 mRNA. Samples were obtained from HIV-positive and negative patients whose CD4 and CD8 counts had been determined via Flow Cytometry. The quantity of CD4 (n = 13) and CD8 (n = 28) mRNA standardized according to GAPDH mRNA quantities, all determined by QC-RT-PCR, were compared to cell number as determined by flow cytometry. There was no correlation between CD4 and CD8 cell counts and mRNA levels of CD4 and CD8 as determined by QC-RT-PCR. There is no correlation between CD4 and CD8 mRNA levels and the number of cells expressing these proteins on their surface. CONCLUSION: QC-RT-PCR, and related methodologies are not useful substitutes for assessment of CD4 and CD8 cell numbers in HIV-infected persons

    Site selection spectroscopy in Eu3+-doped lanthanum fluorozirconate glass and glass-ceramic

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    The optical properties of Eu3+-doped glass and transparent glass-ceramic with composition (in mol%) 70.2ZrF4–23.4LaF3–0.6AlF3–5.8GaF3 were investigated by site selective spectroscopy in order to study the effect of ceramization on the symmetry of Eu3 + sites. The glass-ceramic obtained after thermal treatment of the glass ZLAG contains a unique crystalline phase of unknown structure. The analysis and comparison of FLN spectra in these materials are presented and different classes of sites are discussed. We found the presence of two main site distributions for Eu3+ ions of equivalent symmetry (C2v or lower) in the glass and two sites of different symmetry (C2v or lower and C4v or lower) in tthe glass-ceramic (GC). The estimated average crystal field strength for glass and GC decreases with the 5D0 → 7F0 energy. The results suggest that the two kinds of sites identified in the glass correspond to Eu3+ ions in and out of the former network. Decay-time measurements of 5D0 level of Eu3 + evidenced energy transfer between high and low energy sites and showed an increase of lifetime from the glass to the glass-ceramic

    Position resolution and particle identification with the ATLAS EM calorimeter

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    In the years between 2000 and 2002 several pre-series and series modules of the ATLAS EM barrel and end-cap calorimeter were exposed to electron, photon and pion beams. The performance of the calorimeter with respect to its finely segmented first sampling has been studied. The polar angle resolution has been found to be in the range 50-60 mrad/sqrt(E (GeV)). The neutral pion rejection has been measured to be about 3.5 for 90% photon selection efficiency at pT=50 GeV/c. Electron-pion separation studies have indicated that a pion fake rate of (0.07-0.5)% can be achieved while maintaining 90% electron identification efficiency for energies up to 40 GeV.Comment: 32 pages, 22 figures, to be published in NIM

    Energy Linearity and Resolution of the ATLAS Electromagnetic Barrel Calorimeter in an Electron Test-Beam

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    A module of the ATLAS electromagnetic barrel liquid argon calorimeter was exposed to the CERN electron test-beam at the H8 beam line upgraded for precision momentum measurement. The available energies of the electron beam ranged from 10 to 245 GeV. The electron beam impinged at one point corresponding to a pseudo-rapidity of eta=0.687 and an azimuthal angle of phi=0.28 in the ATLAS coordinate system. A detailed study of several effects biasing the electron energy measurement allowed an energy reconstruction procedure to be developed that ensures a good linearity and a good resolution. Use is made of detailed Monte Carlo simulations based on Geant which describe the longitudinal and transverse shower profiles as well as the energy distributions. For electron energies between 15 GeV and 180 GeV the deviation of the measured incident electron energy over the beam energy is within 0.1%. The systematic uncertainty of the measurement is about 0.1% at low energies and negligible at high energies. The energy resolution is found to be about 10% sqrt(E) for the sampling term and about 0.2% for the local constant term

    Are chiropractors in the uk primary healthcare or primary contact practitioners?: a mixed methods study

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    <p>Abstract</p> <p>Background</p> <p>One of the debates regarding the role of chiropractors is whether or not they should be considered as primary healthcare practitioners. Primary care is often used to describe chiropractic but without any definition of what is meant by the term. Primary healthcare itself has many definitions and this adds to the problem. Existing research literature, based mostly in the USA, suggests that the use of the title "primary healthcare professional" by chiropractors is central to the identity of the profession. It has also been suggested that the concept of primary care is misused by chiropractors because they have not examined the concept in detail and thus do not understand it. For the sake of quality of patient care and for the legitimacy of the profession, chiropractors in the UK need to agree on their healthcare role. This study aimed to examine the opinions of chiropractors towards the use of the term primary healthcare when applied to chiropractic practice within the UK.</p> <p>Methods</p> <p>A sequential study of exploratory design was used; this model is characterised by an initial phase of qualitative data collection and analysis that precedes and informs the quantitative phase of data collection and analysis. In this study, interviews with members of chiropractic teaching faculty were used to inform the development of a questionnaire used to survey the opinions of chiropractors in the UK.</p> <p>Results</p> <p>There was a general consensus of opinion that chiropractors are primary contact practitioners, who work in a primary healthcare setting and that to be able to fulfil this healthcare role, chiropractors must be able to diagnose patients and refer when required. Participants did not feel that chiropractors are able to treat all of the most common medical conditions that present in a primary healthcare setting.</p> <p>Conclusions</p> <p>The findings of this study suggest that chiropractors in the UK view their role as one of a primary contact healthcare practitioner and that this view is held irrespective of the country in which they were educated or the length of time in practice.</p> <p>Further research needs to be developed to evaluate the findings of the current study within a wider healthcare context. In particular the opinions of other healthcare professionals towards the role of chiropractors in healthcare, need to be examined in more detail.</p

    Roughness effect on photoluminescence of cerium doped zinc oxide thin films

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    Undoped and cerium doped zinc oxide thin films have been prepared by spray pyrolysis technique. The influence of Ce as doping agent on the optical and nonlinear optical properties was carefully investigated using transmission, X-ray diffraction, photoluminescence, atomic force microscopy (AFM), and third harmonic generation (THG). It has been found a deep correlation between the surface roughness and the optical properties. In fact the roughness deteriorates the luminescence and nonlinear response, in a sense that the highest luminescence intensity and nonlinear susceptibility χ(3) are obtained for the smoothest layer.Doped layers are characterized with a high visible luminescence, attributed to cerium transitions, and susceptibilities in the range of 6.38 × 10−13 esu

    Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb−1 of s√=7TeV proton-proton collisions

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    Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb−1 of pp collision data at s√=7TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≄6 to ≄9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m 0, gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ Îł, H → Z Z∗ →4l and H →W W∗ →lÎœlÎœ. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined ïŹts probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Standalone vertex ïŹnding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

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    A measurement of the production cross-section for top quark pairs(\ttbar) in pppp collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron ee or muon Ό\mu) with large missing transverse energy and at least four jets, and dilepton (eeee, ΌΌ\mu\mu or eΌe\mu) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be 12.2±3.912.2 \pm 3.9 events and 2.5±0.62.5 \pm 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde
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