113 research outputs found

    Aged-senescent cells contribute to impaired heart regeneration

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    Aging leads to increased cellular senescence and is associated with decreased potency of tissueā€specific stem/progenitor cells. Here, we have done an extensive analysis of cardiac progenitor cells (CPCs) isolated from human subjects with cardiovascular disease, aged 32ā€“86 years. In aged subjects (>70 years old), over half of CPCs are senescent (p16INK4A, SAā€Ī²ā€gal, DNA damage Ī³H2AX, telomere length, senescenceā€associated secretory phenotype [SASP]), unable to replicate, differentiate, regenerate or restore cardiac function following transplantation into the infarcted heart. SASP factors secreted by senescent CPCs renders otherwise healthy CPCs to senescence. Elimination of senescent CPCs using senolytics abrogates the SASP and its debilitative effect in vitro. Global elimination of senescent cells in aged mice (INKā€ATTAC or wildā€type mice treated with D + Q senolytics) in vivo activates resident CPCs and increased the number of small Ki67ā€, EdUā€positive cardiomyocytes. Therapeutic approaches that eliminate senescent cells may alleviate cardiac deterioration with aging and restore the regenerative capacity of the heart.This work was supported by British Heart Foundation project grant PG/14/11/30657 (GMEā€H and J.E.C.), NIH grant AG13925 (JLK), the Connor Group (JLK), Robert J. and Theresa W. Ryan (JLK), Robert and Arlene Kogod (JLK), the Noaber Foundation (JLK), Glenn/American Federation for Aging Research (AFAR) BIG Award (J.L.K.) and Italian Ministry of Health grant GRā€2010ā€2318945

    Alexithymia in juvenile primary headache sufferers: a pilot study

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    Starting in the 1990s, there has been accumulating evidence of alexithymic characteristics in adult patients with primary headache. Little research has been conducted, however, on the relationship between alexithymia and primary headache in developmental age. In their research on alexithymia in the formative years, the authors identified one of the most promising prospects for research, as discussed here. The aim of this study was to verify whether there is: (a) a link between tension-type headache and alexithymia in childhood and early adolescence; and (b) a correlation between alexithymia in children/preadolescents and their mothers. This study was based on an experimental group of 32 patients (26 females and 6 males, aged from 8 to 15Ā years, mean 11.2Ā Ā±Ā 2.0) suffering from tension-type headache and 32 control subjects (26 females and 6 males, aged from 8 to 15Ā years, mean 11.8Ā Ā±Ā 1.6). Tension-type headache was diagnosed by applying the International Headache Classification (ICHD-II, 2004). The alexithymic construct was measured using an Italian version of the Alexithymia Questionnaire for Children in the case of the juvenile patients and the Toronto Alexithymia Scale (TAS-20) for their mothers. Higher rates of alexithymia were observed in the children/preadolescents in the experimental group (EG) than in the control group; in the EG there was no significant correlation between the alexithymia rates in the children/preadolescents and in their mothers

    Measurement of the ttĀÆttĀÆ production cross section in pp collisions at āˆšs=13 TeV with the ATLAS detector

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    A measurement of four-top-quark production using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the Large Hadron Collider corresponding to an integrated luminosity of 139 fbāˆ’1 is presented. Events are selected if they contain a single lepton (electron or muon) or an opposite-sign lepton pair, in association with multiple jets. The events are categorised according to the number of jets and how likely these are to contain b-hadrons. A multivariate technique is then used to discriminate between signal and background events. The measured four-top-quark production cross section is found to be 26+17āˆ’15 fb, with a corresponding observed (expected) significance of 1.9 (1.0) standard deviations over the background-only hypothesis. The result is combined with the previous measurement performed by the ATLAS Collaboration in the multilepton final state. The combined four-top-quark production cross section is measured to be 24+7āˆ’6 fb, with a corresponding observed (expected) signal significance of 4.7 (2.6) standard deviations over the background-only predictions. It is consistent within 2.0 standard deviations with the Standard Model expectation of 12.0 Ā± 2.4 fb

    Measurements of Higgs bosons decaying to bottom quarks from vector boson fusion production with the ATLAS experiment at āˆš=13TeV

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    The paper presents a measurement of the Standard Model Higgs Boson decaying to b-quark pairs in the vector boson fusion (VBF) production mode. A sample corresponding to 126 fbāˆ’1 of sāˆš=13TeV protonā€“proton collision data, collected with the ATLAS experiment at the Large Hadron Collider, is analyzed utilizing an adversarial neural network for event classification. The signal strength, defined as the ratio of the measured signal yield to that predicted by the Standard Model for VBF Higgs production, is measured to be 0.95+0.38āˆ’0.36 , corresponding to an observed (expected) significance of 2.6 (2.8) standard deviations from the background only hypothesis. The results are additionally combined with an analysis of Higgs bosons decaying to b-quarks, produced via VBF in association with a photon

    Muon reconstruction and identification efficiency in ATLAS using the full Run 2 pp collision data set at \sqrt{s}=13 TeV

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    This article documents the muon reconstruction and identification efficiency obtained by the ATLAS experiment for 139 \hbox {fb}^{-1} of pp collision data at \sqrt{s}=13 TeV collected between 2015 and 2018 during Run 2 of the LHC. The increased instantaneous luminosity delivered by the LHC over this period required a reoptimisation of the criteria for the identification of prompt muons. Improved and newly developed algorithms were deployed to preserve high muon identification efficiency with a low misidentification rate and good momentum resolution. The availability of large samples of Z\rightarrow \mu \mu and J/\psi \rightarrow \mu \mu decays, and the minimisation of systematic uncertainties, allows the efficiencies of criteria for muon identification, primary vertex association, and isolation to be measured with an accuracy at the per-mille level in the bulk of the phase space, and up to the percent level in complex kinematic configurations. Excellent performance is achieved over a range of transverse momenta from 3 GeV to several hundred GeV, and across the full muon detector acceptance of |\eta |<2.7

    Measurements of W+Wāˆ’+ ā‰„ 1 jet production cross-sections in pp collisions at s \sqrt{s} = 13 TeV with the ATLAS detector

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    Fiducial and differential cross-section measurements of W+Wāˆ’ production in association with at least one hadronic jet are presented. These measurements are sensitive to the properties of electroweak-boson self-interactions and provide a test of perturbative quantum chromodynamics and the electroweak theory. The analysis is performed using proton-proton collision data collected at p s = 13TeV with the ATLAS experiment, corresponding to an integrated luminosity of 139 fbāˆ’1. Events are selected with exactly one oppositely charged electron-muon pair and at least one hadronic jet with a transverse momentum of pT > 30 GeV and a pseudorapidity of |ļæ½| < 4.5. After subtracting the background contributions and correcting for detector effects, the jet-inclusive W+Wāˆ’+ ļæ½ 1 jet fiducial cross-section and W+Wāˆ’+ jets differential cross-sections with respect to several kinematic variables are measured. These measurements include leptonic quantities, such as the lepton transverse momenta and the transverse mass of the W+Wāˆ’ system, as well as jet-related observables such as the leading jet transverse momentum and the jet multiplicity. Limits on anomalous triple-gauge-boson couplings are obtained in a phase space where interference between the Standard Model amplitude and the anomalous amplitude is enhanced

    Search for bottom-squark pair production in pp collision events at āˆšs=13 TeV with hadronically decaying Ļ„-leptons, b-jets, and missing transverse momentum using the ATLAS detector

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    A search for pair production of bottom squarks in events with hadronically decaying Ļ„ -leptons, b -tagged jets, and large missing transverse momentum is presented. The analyzed dataset is based on proton-proton collisions at āˆš s = 13 ā€‰ ā€‰ TeV delivered by the Large Hadron Collider and recorded by the ATLAS detector from 2015 to 2018, and corresponds to an integrated luminosity of 139 ā€‰ ā€‰ fb āˆ’ 1 . The observed data are compatible with the expected Standard Model background. Results are interpreted in a simplified model where each bottom squark is assumed to decay into the second-lightest neutralino Ėœ Ļ‡ 0 2 and a bottom quark, with Ėœ Ļ‡ 0 2 decaying into a Higgs boson and the lightest neutralino Ėœ Ļ‡ 0 1 . The search focuses on final states where at least one Higgs boson decays into a pair of hadronically decaying Ļ„ -leptons. This allows the acceptance and thus the sensitivity to be significantly improved relative to the previous results at low masses of the Ėœ Ļ‡ 0 2 , where bottom-squark masses up to 850 GeV are excluded at the 95% confidence level, assuming a mass difference of 130 GeV between Ėœ Ļ‡ 0 2 and Ėœ Ļ‡ 0 1 . Model-independent upper limits are also set on the cross section of processes beyond the Standard Model

    Measurements of sensor radiation damage in the ATLAS inner detector using leakage currents

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    Non-ionizing energy loss causes bulk damage to the silicon sensors of the ATLAS pixel and strip detectors. This damage has important implications for data-taking operations, charged-particle track reconstruction, detector simulations, and physics analysis. This paper presents simulations and measurements of the leakage current in the ATLAS pixel detector and semiconductor tracker as a function of location in the detector and time, using data collected in Run 1 (2010ā€“2012) and Run 2 (2015ā€“2018) of the Large Hadron Collider. The extracted fluence shows a much stronger |z|-dependence in the innermost layers than is seen in simulation. Furthermore, the overall fluence on the second innermost layer is significantly higher than in simulation, with better agreement in layers at higher radii. These measurements are important for validating the simulation models and can be used in part to justify safety factors for future detector designs and interventions.publishedVersio

    Measurement of the energy asymmetry in t(t)over-barj production at 13 TeV with the ATLAS experiment and interpretation in the SMEFT framework

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    A measurement of the energy asymmetry in jet-associated top-quark pair production is presented using 139ā€‰fbāˆ’1139\,{\mathrm {fb}}^{-1} 139 fb - 1 of data collected by the ATLAS detector at the Large Hadron Collider during pp collisions at s=13ā€‰TeV\sqrt{s}=13\,\text {TeV} s = 13 TeV . The observable measures the different probability of top and antitop quarks to have the higher energy as a function of the jet scattering angle with respect to the beam axis. The energy asymmetry is measured in the semileptonic ttĖ‰t{\bar{t}} t t ĀÆ decay channel, and the hadronically decaying top quark must have transverse momentum above 350ā€‰GeV350\,\text {GeV} 350 GeV . The results are corrected for detector effects to particle level in three bins of the scattering angle of the associated jet. The measurement agrees with the SM prediction at next-to-leading-order accuracy in quantum chromodynamics in all three bins. In the bin with the largest expected asymmetry, where the jet is emitted perpendicular to the beam, the energy asymmetry is measured to be āˆ’0.043Ā±0.020-0.043\pm 0.020 - 0.043 Ā± 0.020 , in agreement with the SM prediction of āˆ’0.037Ā±0.003-0.037\pm 0.003 - 0.037 Ā± 0.003 . Interpreting this result in the framework of the Standard Model effective field theory (SMEFT), it is shown that the energy asymmetry is sensitive to the top-quark chirality in four-quark operators and is therefore a valuable new observable in global SMEFT fits
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