Publications (61) View all
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Article: Proliferative activity in ischemia/reperfusion injury in hepatectomized mice: effect of N-acetylcysteine.
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ABSTRACT: Dysfunction of the liver after transplantation may be related to the graft size and ischemia/reperfusion (I/R) injury. N-Acetylcysteine (NAC) exerts beneficial effects on livers undergoing ischemia reperfusion. We sought to evaluate NAC modulation on reduced livers associated with I/R injury. Male C57BL/6 mice of 8 weeks of age were divided into groups: 50% hepatectomy (G-Hep); NAC (G-Hep + NAC [150 mg/kg]) via vena cava 15 minutes before hepatectomy; ischemia (G-Hep + IR); NAC with hepatectomy (G-IR + Hep + Nac); and IR using 30 minutes selective hepatic occlusion and reperfusion for 24 hours. After 24 hours, the remaining liver was removed, for staining with hematoxylin and eosin or labeling by proliferating cell nuclear antigen. Blood was collected for biochemical evaluations. Significance was considered for P ≤ .05. Aspartate aminotransferase was high in all studied groups reflecting the hepatectomy and intervention. injuries. However, when assessing alanine aminotransferase, which depicts liver function, induction of IR promoted a greater increase than hepatectomy (P = .0003). NAC decreased ALT activity in all groups, even in association with I/R (P < .05), reflecting a modulation of the injury. Necrosis resulting from IR was mitigated by NAC. The experimental model of 50% reduced live promoted regeneration of the hepatic remnant, which was accentuated by NAC, according to the total number of hepatocytes and PCNA values. NAC preserved the remnant liver in mice and stimulates regeneration even after IR injury.Transplantation Proceedings 10/2012; 44(8):2321-5. · 1.00 Impact Factor -
Article: Measurement of the W → ℓν and Z/γ* → ℓℓ production cross sections in proton-proton collisions at with the ATLAS detector
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ABSTRACT: First measurements of the W → ℓν and Z/γ * → ℓℓ (ℓ = e, μ) production cross sections in proton-proton collisions at Ös = 7\textTeV \sqrt {s} = 7\;{\text{TeV}} are presented using data recorded by the ATLAS experiment at the LHC. The results are based on 2250 W → ℓν and 179 Z/γ * → ℓℓ candidate events selected from a data set corresponding to an integrated luminosity of approximately 320 nb. The measured total W and Z/γ ∗-boson production cross sections times the respective leptonic branching ratios for the combined electron and muon channels are sW\texttot \sigma_W^{\text{tot}} . BR(W → ℓν) = 9.96 ± 0.23(stat) ± 0.50(syst) ± 1.10(lumi) nb and sZ / g \texttot \sigma_{{{Z} \left/ {\gamma } \right.}}^{\text{tot}} BR(Z/γ ∗ → ℓℓ) = 0.82 ± 0.06 (stat) ± 0.05 (syst) ± 0.09(lumi) nb (within the invariant mass window 66 < m ℓℓ < 116GeV). The W/Z cross-section ratio is measured to be 11.7 ± 0.9(stat) ± 0.4(syst). In addition, measurements of the W + and W − production cross sections and of the lepton charge asymmetry are reported. Theoretical predictions based on NNLO QCD calculations are found to agree with the measurements. KeywordsHadron-Hadron ScatteringJournal of High Energy Physics 04/2012; 2010(12):1-65. · 5.83 Impact Factor -
Article: Readiness of the ATLAS liquid argon calorimeter for LHC collisions
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ABSTRACT: The ATLAS liquid argon calorimeter has been operating continuously since August 2006. At this time, only part of the calorimeter was readout, but since the beginning of 2008, all calorimeter cells have been connected to the ATLAS readout system in preparation for LHC collisions. This paper gives an overview of the liquid argon calorimeter performance measured in situ with random triggers, calibration data, cosmic muons, and LHC beam splash events. Results on the detector operation, timing performance, electronics noise, and gain stability are presented. High energy deposits from radiative cosmic muons and beam splash events allow to check the intrinsic constant term of the energy resolution. The uniformity of the electromagnetic barrel calorimeter response along η (averaged overφ) is measured at the percent level using minimum ionizing cosmic muons. Finally, studies of electromagnetic showers from radiative muons have been used to cross-check the Monte Carlo simulation. The performance results obtained using the ATLAS readout, data acquisition, and reconstruction software indicate that the liquid argon calorimeter is well-prepared for collisions at the dawn of the LHC era.European Physical Journal C 04/2012; 70(3):723-753. · 3.63 Impact Factor -
Article: Drift Time Measurement in the ATLAS Liquid Argon Electromagnetic Calorimeter using Cosmic Muons
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ABSTRACT: The ionization signals in the liquid argon of the ATLAS electromagnetic calorimeter are studied in detail using cosmic muons. In particular, the drift time of the ionization electrons is measured and used to assess the intrinsic uniformity of the calorimeter gaps and estimate its impact on the constant term of the energy resolution. The drift times of electrons in the cells of the second layer of the calorimeter are uniform at the level of 1.3% in the barrel and 2.8% in the endcaps. This leads to an estimated contribution to the constant term of (0.29+0.05-0.04)(0.29^{+0.05}_{-0.04})% in the barrel and (0.54+0.06-0.04)(0.54^{+0.06}_{-0.04})% in the endcaps. The same data are used to measure the drift velocity of ionization electrons in liquid argon, which is found to be 4.61±0.07mm/μs at 88.5K and 1kV/mm.European Physical Journal C 04/2012; 70(3):755-785. · 3.63 Impact Factor -
Article: Charged-particle multiplicities in pp interactions measured with the ATLAS detector at the LHC
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ABSTRACT: Measurements are presented from proton–proton collisions at centre-of-mass energies of , 2.36 and 7 TeV recorded with the ATLAS detector at the LHC. Events were collected using a single-arm minimum-bias trigger. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the relationship between the mean transverse momentum and charged-particle multiplicity are measured. Measurements in different regions of phase space are shown, providing diffraction-reduced measurements as well as more inclusive ones. The observed distributions are corrected to well-defined phase-space regions, using model-independent corrections. The results are compared to each other and to various Monte Carlo (MC) models, including a new AMBT1 pythia6 tune. In all the kinematic regions considered, the particle multiplicities are higher than predicted by the MC models. The central charged-particle multiplicity per event and unit of pseudorapidity, for tracks with pT>100 MeV, is measured to be 3.483±0.009 (stat)±0.106 (syst) at and 5.630±0.003 (stat)±0.169 (syst) at .New Journal of Physics 05/2011; 13(5):053033. · 4.18 Impact Factor
