202 research outputs found

    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

    Microparticles Harboring Sonic Hedgehog Morphogen Improve the Vasculogenesis Capacity of Endothelial Progenitor Cells Derived from Myocardial Infarction Patients.

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    Endothelial progenitor cells (EPC) play a role in endothelium integrity maintenance and regeneration. Decreased numbers of EPC or their impaired function correlates with an increase in cardiovascular events. Thus, EPC are important predictors of cardiovascular mortality and morbidity. Microparticles carrying Sonic hedgehog (Shh) morphogen (MPShhþ) trigger pro-angiogenic responses, both in endothelial cells and in ischaemic rodent models. Here, we propose that MPShhþ regulates EPC function, thus enhancing vasculogenesis, and correcting the defects in dysfunctional EPC obtained from acute myocardial infarction (AMI) patients

    Glycosylation as new pharmacological strategies for diseases associated with excessive angiogenesis

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    Angiogenesis is a complex process describing the growth of new blood vessels from existing vasculature, and is triggered by local pro-angiogenic factors, such as vascular endothelial growth factor (VEGF), which increase the metabolism of endothelial cells (ECs). Angiogenesis takes part in various physiological conditions such as embryogenesis, placental growth, and in pathological conditions such as tumor growth, diabetic retinopathy, rheumatoid arthritis (RA) and ischemic diseases. Current therapies against excessive angiogenesis target vascular growth signaling. However, tumors often counteract these therapies through adaptive mechanisms, thus novel alternative anti-angiogenic strategies are needed. Targeting metabolism is a new anti-angiogenic paradigm, especially through the inhibition of energy metabolism and glycosylation, with the perspective of maintaining the delicate balance between the beneficial and deleterious effects of excessive angiogenesis in patients. Recent studies described a role for EC glycolysis and its main regulator 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) in the regulation of angiogenesis, but only few studies are related to the role of the hexosamine biosynthesis pathway during angiogenesis. Glycosylation allows the formation of glycoproteins, glycolipids and proteoglycans and impacts many pathways. The addition of glycans to N-linked proteins is catalyzed by the enzymatic activity of N-acetylglucosaminyltransferases (GnTs), which regulates the glycosylation status of key angiogenic factors such as VEGF receptor 2 (VEGFR2) and Notch. In addition, glycan-galectin (Gal) interactions regulate vascular signaling programs and may contribute to tumor adaptations to anti-angiogenic strategies. Herein, we review novel pharmacological strategies targeting glycosylation, which could be used to decrease excessive angiogenesis in pathological conditions

    Measurement of time resolution of the Mu2e LYSO calorimeter prototype

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    In this paper we present the time resolution measurements of the Lutetium–Yttrium Oxyorthosilicate (LYSO) calorimeter prototype for the Mu2e experiment. The measurements have been performed using the e− beam of the Beam Test Facility (BTF) in Frascati, Italy in the energy range from 100 to 400 MeV. The calorimeter prototype consisted of twenty five 30 x 30 x 130 mm^3, LYSO crystals read out by 10 × 10 mm^2 Hamamatsu Avalanche Photodiodes (APDs). The energy dependence of the measured time resolution can be parametrized as σ_t(E)=a/√E/GeV⊕b, with the stochastic and constant terms a=(51 ± 1)ps and b=(10 ± 4)ps, respectively. This corresponds to the time resolution of (162 ±4 )ps at 100 MeV

    Design and construction of the MicroBooNE Cosmic Ray Tagger system

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    The MicroBooNE detector utilizes a liquid argon time projection chamber (LArTPC) with an 85 t active mass to study neutrino interactions along the Booster Neutrino Beam (BNB) at Fermilab. With a deployment location near ground level, the detector records many cosmic muon tracks in each beam-related detector trigger that can be misidentified as signals of interest. To reduce these cosmogenic backgrounds, we have designed and constructed a TPC-external Cosmic Ray Tagger (CRT). This sub-system was developed by the Laboratory for High Energy Physics (LHEP), Albert Einstein center for fundamental physics, University of Bern. The system utilizes plastic scintillation modules to provide precise time and position information for TPC-traversing particles. Successful matching of TPC tracks and CRT data will allow us to reduce cosmogenic background and better characterize the light collection system and LArTPC data using cosmic muons. In this paper we describe the design and installation of the MicroBooNE CRT system and provide an overview of a series of tests done to verify the proper operation of the system and its components during installation, commissioning, and physics data-taking

    Microparticles Carrying Sonic Hedgehog Favor Neovascularization through the Activation of Nitric Oxide Pathway in Mice

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    BACKGROUND: Microparticles (MPs) are vesicles released from plasma membrane upon cell activation and during apoptosis. Human T lymphocytes undergoing activation and apoptosis generate MPs bearing morphogen Shh (MPs(Shh+)) that are able to regulate in vitro angiogenesis.METHODOLOGY/PRINCIPAL FINDINGS: Here, we investigated the ability of MPs(Shh+) to modulate neovascularization in a model of mouse hind limb ischemia. Mice were treated in vivo for 21 days with vehicle, MPs(Shh+), MPs(Shh+) plus cyclopamine or cyclopamine alone, an inhibitor of Shh signalling. Laser doppler analysis revealed that the recovery of the blood flow was 1.4 fold higher in MPs(Shh+)-treated mice than in controls, and this was associated with an activation of Shh pathway in muscles and an increase in NO production in both aorta and muscles. MPs(Shh+)-mediated effects on flow recovery and NO production were completely prevented when Shh signalling was inhibited by cyclopamine. In aorta, MPs(Shh+) increased activation of eNOS/Akt pathway, and VEGF expression, being inhibited by cyclopamine. By contrast, in muscles, MPs(Shh+) enhanced eNOS expression and phosphorylation and decreased caveolin-1 expression, but cyclopamine prevented only the effects of MPs(Shh+) on eNOS pathway. Quantitative RT-PCR revealed that MPs(Shh+) treatment increased FGF5, FGF2, VEGF A and C mRNA levels and decreased those of α5-integrin, FLT-4, HGF, IGF-1, KDR, MCP-1, MT1-MMP, MMP-2, TGFβ1, TGFβ2, TSP-1 and VCAM-1, in ischemic muscles. CONCLUSIONS/SIGNIFICANCE: These findings suggest that MPs(Shh+) may contribute to reparative neovascularization after ischemic injury by regulating NO pathway and genes involved in angiogenesis

    Convolutional Neural Networks Applied to Neutrino Events in a Liquid Argon Time Projection Chamber

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    We present several studies of convolutional neural networks applied to data coming from the MicroBooNE detector, a liquid argon time projection chamber (LArTPC). The algorithms studied include the classification of single particle images, the localization of single particle and neutrino interactions in an image, and the detection of a simulated neutrino event overlaid with cosmic ray backgrounds taken from real detector data. These studies demonstrate the potential of convolutional neural networks for particle identification or event detection on simulated neutrino interactions. We also address technical issues that arise when applying this technique to data from a large LArTPC at or near ground level

    Ionization Electron Signal Processing in Single Phase LArTPCs II. Data/Simulation Comparison and Performance in MicroBooNE

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    The single-phase liquid argon time projection chamber (LArTPC) provides a large amount of detailed information in the form of fine-grained drifted ionization charge from particle traces. To fully utilize this information, the deposited charge must be accurately extracted from the raw digitized waveforms via a robust signal processing chain. Enabled by the ultra-low noise levels associated with cryogenic electronics in the MicroBooNE detector, the precise extraction of ionization charge from the induction wire planes in a single-phase LArTPC is qualitatively demonstrated on MicroBooNE data with event display images, and quantitatively demonstrated via waveform-level and track-level metrics. Improved performance of induction plane calorimetry is demonstrated through the agreement of extracted ionization charge measurements across different wire planes for various event topologies. In addition to the comprehensive waveform-level comparison of data and simulation, a calibration of the cryogenic electronics response is presented and solutions to various MicroBooNE-specific TPC issues are discussed. This work presents an important improvement in LArTPC signal processing, the foundation of reconstruction and therefore physics analyses in MicroBooNE.Comment: 54 pages, 36 figures; the first part of this work can be found at arXiv:1802.0870
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