851 research outputs found

    Transapical off-pump echo-guided mitral valve repair with neochordae implantation mid-term outcomes

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    Background: The NeoChord echo-guided transapical beating heart repair is a promising early-stage minimally invasive surgical procedure for degenerative mitral valve (MV) regurgitation (DMR) correction. The technique has been improved since its inception following procedure standardization, patient selection optimization, and learning curve stabilization. We hereby present the mid-term clinical results through three years of our large single center experience. Methods: All consecutive patients with severe symptomatic DMR due to prolapse or flail of one or both mitral leaflets that underwent the NeoChord procedure between November 2013 and June 2019 were included. Patients were categorized according to MV anatomy; Type A isolated central posterior leaflet prolapse and/or flail, Type B posterior multi-segment prolapse and/or flail, Type C anterior and/or bi-leaflet prolapse or flail, Type D paracommissural prolapse and/or flail and/or significant leaflet and/or annular calcifications. Patients underwent clinical and echocardiographic follow-up at one, three, six, twelve months and yearly thereafter. Clinical outcomes and the composite primary endpoint (patient success) were defined according to Mitral Valve Academic Research Consortium (MVARC) criteria. Mitral regurgitation (MR) severity was graded as absent, mild, moderate and severe according to American Society of Echocardiography (ASE) and European Society of Cardiology (ESC) guidelines. Results: Two hundred and three patients were included; median follow-up was 24 months [interquartile range (IQR), 9–36]. Median age was 64 years (IQR, 54–74 years), median Society of Thoracic Surgeons (STS) Predicted Risk of Mortality (PROM) was 0.60% (IQR, 0.32–1.44%). There were 106 Type A patients (52.2%), 68 Type B (33.5%), 16 Type C (7.9%), and 13 Type D (6.4%). Kaplan-Meier estimate of survival was 99.0%±0.7% at one and two years and 94.0%±2.9% at three years. At one-year follow-up patient success was 91.2%±2.0% and 111 patients (74%) presented a residual MR mild or less (1+). At three-year follow-up patient success was 81.2%±3.8% and 32 patients (64%) had a residual MR mild or less (1+). Patient success was significantly different according to anatomical type (P=0.001). Echocardiographic analysis showed a significant acute left ventricle and left atrial reverse remodeling that was maintained up to three years. Conclusions: The NeoChord echo-guided transapical beating heart repair procedure demonstrated good clinical outcomes and echocardiographic results up to three-year follow-up

    Definition of the Prognostic Role of MGMT Promoter Methylation Value by Pyrosequencing in Newly Diagnosed IDH Wild‐Type Glioblastoma Patients Treated with Radiochemotherapy: A Large Multicenter Study

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    Background. O6‐methylguanine (O6‐MeG)‐DNA methyltransferase (MGMT) methylation status is a predictive factor for alkylating treatment efficacy in glioblastoma patients, but its prognostic role is still unclear. We performed a large, multicenter study to evaluate the association between MGMT methylation value and survival. Methods. We evaluated glioblastoma patients with an assessment of MGMT methylation status by pyrosequencing from nine Italian centers. The inclusion criteria were histological diagnosis of IDH wild‐type glioblastoma, Eastern Cooperative Oncology Group Performance Status (ECOG‐PS) ≀2, and radio‐chemotherapy treatment with temozolomide. The relationship between OS and MGMT was investigated with a time‐dependent Receiver Operating Characteristics (ROC) curve and Cox regression models. Results. In total, 591 newly diagnosed glioblastoma patients were analyzed. The median OS was 16.2 months. The ROC analysis suggested a cut‐off of 15% for MGMT methylation. The 2‐year Overall Survival (OS) was 18.3% and 51.8% for MGMT methylation <15% and ≄15% (p < 0.0001). In the multivariable analysis, MGMT methylation <15% was associated with impaired survival (p <0.00001). However, we also found a non‐linear association between MGMT methylation and OS (p = 0.002): median OS was 14.8 months for MGMT in 0–4%, 18.9 months for MGMT in 4–40%, and 29.9 months for MGMT in 40– 100%. Conclusions. Our findings suggested a non‐linear relationship between OS and MGMT promoter methylation, which implies a varying magnitude of prognostic effect across values of MGMT promoter methylation by pyrosequencing in newly diagnosed IDH wild‐type glioblastoma patients treated with chemoradiotherapy

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

    Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

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    Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations

    Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS

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    The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ÏˆÎł (with J/ψ → ÎŒ + ÎŒ −) where photons are reconstructed from Îł → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured

    Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector

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    Results of a search for H → τ τ decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb−1 and 20.3 fb−1 at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV respectively. All combinations of leptonic (τ → `ÎœÎœÂŻ with ` = e, ”) and hadronic (τ → hadrons Îœ) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalised to the Standard Model expectation, of ” = 1.43 +0.43 −0.37 is consistent with the predicted Yukawa coupling strength in the Standard Model

    Measurement of the top pair production cross section in 8 TeV proton-proton collisions using kinematic information in the lepton plus jets final state with ATLAS

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    A measurement is presented of the ttˉt\bar{t} inclusive production cross-section in pppp collisions at a center-of-mass energy of s=8\sqrt{s}=8 TeV using data collected by the ATLAS detector at the CERN Large Hadron Collider. The measurement was performed in the lepton+jets final state using a data set corresponding to an integrated luminosity of 20.3 fb−1^{-1}. The cross-section was obtained using a likelihood discriminant fit and bb-jet identification was used to improve the signal-to-background ratio. The inclusive ttˉt\bar{t} production cross-section was measured to be 260±1(stat.)−23+22(syst.)±8(lumi.)±4(beam)260\pm 1{\textrm{(stat.)}} ^{+22}_{-23} {\textrm{(syst.)}}\pm 8{\textrm{(lumi.)}}\pm 4{\mathrm{(beam)}} pb assuming a top-quark mass of 172.5 GeV, in good agreement with the theoretical prediction of 253−15+13253^{+13}_{-15} pb. The ttˉ→(e,ÎŒ)+jetst\bar{t}\to (e,\mu)+{\mathrm{jets}} production cross-section in the fiducial region determined by the detector acceptance is also reported.Comment: Published version, 19 pages plus author list (35 pages total), 3 figures, 2 tables, all figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2013-06

    Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector

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    The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +cÂŻÂŻ)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−sÂŻÂŻÂŻ quark asymmetry
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