1,407 research outputs found

    Components Qualification for a Possible use in the Mu2e Calorimeter Waveform Digitizers

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    The Mu2e experiment at Fermilab searches for the charged flavor violating conversion of a muon into an electron in the Coulomb field of a nucleus. The detector consists of a straw tube tracker and a CSI crystal electromagnetic calorimeter, both housed in a superconducting solenoid. Both the front-end and the digital electronics, located inside the cryostat, will be operated in vacuum under a 1 T magnetic field, having to sustain the high flux of neutrons and ionizing particles coming from the muons stopping target. These harsh experimental conditions make the design of the calorimeter waveform digitizer quite challenging. All the selected commercial devices must be tested individually and qualified for radiation hardness and operation in high magnetic field. At the moment the expected particles flux and spectra at the digitizers location are not completely simulated and we are using initial rough estimates to select the components for the first prototype. We are gaining experience in the qualification procedures using the selected components but the choice will be frozen only when dose and neutron flux simulations will be completed. The experimental results of the first qualification campaign are presented.Comment: TWEPP 2016 - Topical Workshop on Electronics for Particle Physics, 26-30 September 2016, Karlsruhe Institute of Technology (KIT

    Pre-Production and Quality Assurance of the Mu2e Calorimeter Silicon Photomultipliers

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    The Mu2e electromagnetic calorimeter has to provide precise information on energy, time and position for ∼\sim100 MeV electrons. It is composed of 1348 un-doped CsI crystals, each coupled to two large area Silicon Photomultipliers (SiPMs). A modular and custom SiPM layout consisting of a 3×\times2 array of 6×\times6 mm2^2 UV-extended monolithic SiPMs has been developed to fulfill the Mu2e calorimeter requirements and a pre-production of 150 prototypes has been procured by three international firms (Hamamatsu, SensL and Advansid). A detailed quality assurance process has been carried out on this first batch of photosensors: the breakdown voltage, the gain, the quenching time, the dark current and the Photon Detection Efficiency (PDE) have been determined for each monolithic cell of each SiPMs array. One sample for each vendor has been exposed to a neutron fluency up to ∼\sim8.5~×\times~1011^{11} 1 MeV (Si) eq. n/cm2^{2} and a linear increase of the dark current up to tens of mA has been observed. Others 5 samples for each vendor have undergone an accelerated aging in order to verify a Mean Time To Failure (MTTF) higher than ∼\sim106^{6} hours.Comment: NDIP 2017 - New Developments In Photodetection, 3-7 July 2017, Tours (France

    Diet as prophylaxis and treatment for venous thromboembolism?

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    <p>Abstract</p> <p>Background</p> <p>Both prophylaxis and treatment of venous thromboembolism (VTE: deep venous thrombosis (DVT) and pulmonary emboli (PE)) with anticoagulants are associated with significant risks of major and fatal hemorrhage. Anticoagulation treatment of VTE has been the standard of care in the USA since before 1962 when the U.S. Food and Drug Administration began requiring randomized controlled clinical trials (RCTs) showing efficacy, so efficacy trials were never required for FDA approval. In clinical trials of 'high VTE risk' surgical patients before the 1980s, anticoagulant prophylaxis was clearly beneficial (fatal pulmonary emboli (FPE) without anticoagulants = 0.99%, FPE with anticoagulants = 0.31%). However, observational studies and RCTs of 'high VTE risk' surgical patients from the 1980s until 2010 show that FPE deaths without anticoagulants are about one-fourth the rate that occurs during prophylaxis with anticoagulants (FPE without anticoagulants = 0.023%, FPE while receiving anticoagulant prophylaxis = 0.10%). Additionally, an FPE rate of about 0.012% (35/28,400) in patients receiving prophylactic anticoagulants can be attributed to 'rebound hypercoagulation' in the two months after stopping anticoagulants. Alternatives to anticoagulant prophylaxis should be explored.</p> <p>Methods and Findings</p> <p>The literature concerning dietary influences on VTE incidence was reviewed. Hypotheses concerning the etiology of VTE were critiqued in relationship to the rationale for dietary versus anticoagulant approaches to prophylaxis and treatment.</p> <p>Epidemiological evidence suggests that a diet with ample fruits and vegetables and little meat may substantially reduce the risk of VTE; vegetarian, vegan, or Mediterranean diets favorably affect serum markers of hemostasis and inflammation. The valve cusp hypoxia hypothesis of DVT/VTE etiology is consistent with the development of VTE being affected directly or indirectly by diet. However, it is less consistent with the rationale of using anticoagulants as VTE prophylaxis. For both prophylaxis and treatment of VTE, we propose RCTs comparing standard anticoagulation with low VTE risk diets, and we discuss the statistical considerations for an example of such a trial.</p> <p>Conclusions</p> <p>Because of (a) the risks of biochemical anticoagulation as anti-VTE prophylaxis or treatment, (b) the lack of placebo-controlled efficacy data supporting anticoagulant treatment of VTE, (c) dramatically reduced hospital-acquired FPE incidence in surgical patients without anticoagulant prophylaxis from 1980 - 2010 relative to the 1960s and 1970s, and (d) evidence that VTE incidence and outcomes may be influenced by diet, randomized controlled non-inferiority clinical trials are proposed to compare standard anticoagulant treatment with potentially low VTE risk diets. We call upon the U. S. National Institutes of Health and the U.K. National Institute for Health and Clinical Excellence to design and fund those trials.</p

    Central venous catheter insertion: a bedside procedure for haematological patients.

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    The present management of onco-haematologic patients may require continuous infusion of cytotoxic drugs, use of drugs or concentrated ion solutions which are toxic for the endothelial wall of small vessels, infusion of large amounts of antibiotics or antimycotics, red blood cell and platelet transfusion, and not rarely parenteral nutrition. Such a complex therapy needs a vascular access by a central vein catheter (CVC) insertion. Many types of CVC are available at present: tunnelled Hickman or Hickmanlike catheters, subcutaneous ports, tunnelled catheters with Groshong valve, external untunnelled catheters

    Energy and time resolution for a LYSO matrix prototype of the Mu2e experiment

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    We have measured the performances of a LYSO crystal matrix prototype tested with electron and photon beams in the energy range 60−-450 MeV. This study has been carried out to determine the achievable energy and time resolutions for the calorimeter of the Mu2e experiment.Comment: 2 pages, 3 figures, 13th Pisa Meeting on Advanced Detector

    On the molecular structure of human neuroserpin polymers

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    The polymerization of serpins is at the root of a large class of diseases; the molecular structure of serpin polymers has been recently debated. Here, we study the polymerization kinetics of human neuroserpin by Fourier Transform Infra Red spectroscopy and by time-lapse Size Exclusion Chromatography. Firstly we show that two distinct neuroserpin polymers, formed at 45 and 85 °C, display the same isosbestic points in the Amide I′ band, and therefore share common secondary structure features. We also find a concentration independent polymerization rate at 45 °C, suggesting that the polymerization rate-limiting step is the formation of an activated monomeric species. The polymer structures are consistent with a model that predicts the bare insertion of portions of the reactive center loop into the A β-sheet of neighboring serpin molecule, although with different extents at 45 and 85 °C

    Disease burden and economic impact of diagnosed non-alcoholic steatohepatitis (NASH) in the United Kingdom (UK) in 2018

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    BACKGROUNDS AND AIMS: Non-alcoholic steatohepatitis (NASH) – a progressive subset of non-alcoholic fatty liver disease (NAFLD) – is a chronic liver disease that can progress to advanced fibrosis, cirrhosis, and end-stage liver disease (ESLD) if left untreated. Early-stage NASH is usually asymptomatic, meaning a large proportion of the prevalent population are undiagnosed. Receiving a NASH diagnosis increases the probability that a patient will receive interventions for the purpose of managing their condition. The purpose of this study was to estimate the disease burden and economic impact of diagnosed NASH in the United Kingdom (UK) adult population in 2018. METHODS: The socioeconomic burden of diagnosed NASH from a societal perspective was estimated using cost-of-illness methodology applying a prevalence approach. This involved estimating the number of adults with diagnosed NASH in the UK in a base period (2018) and the economic and wellbeing costs attributable to diagnosed NASH in that period. The analysis was based on a targeted review of the scientific literature, existing databases and consultation with clinical experts, health economists and patient groups. RESULTS: Of the prevalent NASH population in the UK in 2018, an estimated 79.8% were not diagnosed. In particular, of the prevalent population in disease stages F0 to F2, only 2.0% (F0), 2.0% (F1) and 16.5% (F2), respectively, were diagnosed. Total economic costs of diagnosed NASH in the UK ranged from £2.3 billion (lower prevalence scenario, base probability of diagnosis scenario) to £4.2 billion (higher prevalence scenario, base probability of diagnosis scenario). In 2018, people with NASH in the UK were estimated to experience 94,094 to 174,564 disability-adjusted life years (DALYs) overall. Total wellbeing costs associated with NASH in 2018 were estimated to range between £5.6 to £10.5 billion. CONCLUSIONS: The prevention and appropriate management of adult NASH patients could result in reduced economic costs and improvements in wellbeing
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