5,581 research outputs found

    Multigap RPC time resolution to 511 keV annihilation photons

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    The time resolution of Multigap Resistive Plate Counters (MRPCs) to 511511 keV gamma rays has been investigated using a 22^{22}Na source and four detectors. The MRPCs time resolution has been derived from the Time-of-Flight information, measured from pairs of space correlated triggered events. A GEANT4 simulation has been performed to analyze possible setup contributions and to support experimental results. A time resolution (FWHM) of 376376 ps and 312312 ps has been measured for a single MRPC with four 250250 ÎĽ\mum gas gaps by considering respectively one and two independent pairs of detectors.Comment: 25 pages, 14 figure

    Current status and perspectives in lung transplantation

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    A facility for the test of large area muon chambers at high rates

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    Operation of large area muon detectors at the future Large Hadron Collider (LHC) will be characterized by large sustained hit rates over the whole area, reaching the range of kHz/\scm. We describe a dedicated test zone built at CERN to test the performance and the aging of the muon chambers currently under development. A radioactive source delivers photons causing the sustained rate of random hits, while a narrow beam of high energy muons is used to directly calibrate the detector performance. A system of remotely controlled lead filters serves to vary the rate of photons over four orders of magnitude, to allow the study of performance as a function of rate

    The CMS RPC gas gain monitoring system: an overview and preliminary results

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    The status of the CMS RPC Gas Gain Monitoring (GGM) system developed at the Frascati Laboratory of INFN (Istituto Nazionale di Fisica Nucleare) is reported on. The GGM system is a cosmic ray telescope based on small RPC detectors operated with the same gas mixture used by the CMS RPC system. The GGM gain and efficiency are continuously monitored on-line, thus providing a fast and accurate determination of any shift in working point conditions. The construction details and the first result of GGM commissioning are described.Comment: 8 pages, 9 figures, uses lnfprepCMS.sty, presented by L. Benussi at RPC07, Mumbai, INDIA 200

    Cigarette smoke alters IL-33 expression and release in airway epithelial cells

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    AbstractAirway epithelium is a regulator of innate immune responses to a variety of insults including cigarette smoke. Cigarette smoke alters the expression and the activation of Toll Like Receptor 4 (TLR4), an innate immunity receptor. IL-33, an alarmin, increases innate immunity Th2 responses. The aims of this study were to explore whether mini-bronchoalveolar lavage (mini-BAL) or sera from smokers have altered concentrations of IL-33 and whether cigarette smoke extracts (CSE) alter both intracellular expression (mRNA and protein) and release of IL-33 in bronchial epithelial cells. The role of TLR4 in the expression of IL-33 was also explored.Mini-BALs, but not sera, from smokers show reduced concentrations of IL-33. The expression of IL-33 was increased also in bronchial epithelium from smokers. 20% CSE reduced IL-33 release but increased the mRNA for IL-33 by real time PCR and the intracellular expression of IL-33 in bronchial epithelial cells as confirmed by flow cytometry, immunocytochemistry and western blot analysis. The effect of CSE on IL-33 expression was also observed in primary bronchial epithelial cells. IL-33 expression was mainly concentrated within the cytoplasm of the cells. LPS, an agonist of TLR4, reduced IL-33 expression, and an inhibitor of TLR4 increased the intracellular expression of IL-33. In conclusion, the release of IL-33 is tightly controlled and, in smokers, an altered activation of TLR4 may lead to an increased intracellular expression of IL-33 with a limited IL-33 release

    The Upgrade of the CMS RPC System during the First LHC Long Shutdown

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    The CMS muon system includes in both the barrel and endcap region Resistive Plate Chambers (RPC). They mainly serve as trigger detectors and also improve the reconstruction of muon parameters. Over the years, the instantaneous luminosity of the Large Hadron Collider gradually increases. During the LHC Phase 1 (~first 10 years of operation) an ultimate luminosity is expected above its design value of 10^34/cm^2/s at 14 TeV. To prepare the machine and also the experiments for this, two long shutdown periods are scheduled for 2013-2014 and 2018-2019. The CMS Collaboration is planning several detector upgrades during these long shutdowns. In particular, the muon detection system should be able to maintain a low-pT threshold for an efficient Level-1 Muon Trigger at high particle rates. One of the measures to ensure this, is to extend the present RPC system with the addition of a 4th layer in both endcap regions. During the first long shutdown, these two new stations will be equipped in the region |eta|<1.6 with 144 High Pressure Laminate (HPL) double-gap RPCs operating in avalanche mode, with a similar design as the existing CMS endcap chambers. Here, we present the upgrade plans for the CMS RPC system for the fist long shutdown, including trigger simulation studies for the extended system, and details on the new HPL production, the chamber assembly and the quality control procedures.Comment: 9 pages, 6 figures, presented by M.Tytgat at the XI workshop on Resistive Plate Chambers and Related Detectors (RPC2012), INFN - Laboratori Nazionali di Frascati, February 5-10, 201

    Gas Analysis and Monitoring Systems for the RPC Detector of CMS at LHC

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    The Resistive Plate Chambers (RPC) detector of the CMS experiment at the LHC proton collider (CERN, Switzerland) will employ an online gas analysis and monitoring system of the freon-based gas mixture used. We give an overview of the CMS RPC gas system, describe the project parameters and first results on gas-chromatograph analysis. Finally, we report on preliminary results for a set of monitor RPC.Comment: 9 pages, 8 figures. Presented by Stefano Bianco (Laboratori Nazionali di Frascati dell'INFN) at the IEEE NSS, San Diego (USA), October 200

    Determinants of quality of life after lung transplant: an Italian collaborative study

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    Background. With the improvement in survival rates after lung transplantation, concern has arisen about evaluating quality of life (QoL). This multicenter cross-sectional study aimed at describing QoL and identifying factors associated with it. Methods. We assessed QoL in 129 lung transplant recipients from 5 centres in Italy, during scheduled followup visits, using the SF-36, GHQ and St George’s respiratory questionnaires (SGRQ). Results. The SF-36 elicited impaired QoL in the physical, but not in the mental domains (PCS=44; MCS=53). The GHQ identified 29 patients (23%) with psychological discomfort and the SGRQ scores were significantly better than those of patients with chronic respiratory disease. On multivariate analysis, exertional dyspnea was an independent predictor of the PCS (adjusted Δ -6.3 (p5. Conclusions. The study identified exertional dyspnea as the main determinant of QoL as measured both by SF36 (PCS) and GHQ. Other objective measures contributed only to the PCS. Thus, the SF-36 (PCS) and GHQ were useful in identifying patients who needed treatment not only for complications but also psychological support and continued physical rehabilitation
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