971 research outputs found

    Autologous Hematopoietic Stem Cell Transplantation in Multiple Myeloma in the Era of New Drugs

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    Background & Aims. The present retrospective single-center study analysed the impact of high-dose chemotherapy with melphalan with subsequent autologous hematopoietic stem cell transplantation (auto-HSCT) on survival in multiple myeloma (MM) in the era of new induction regimens. Materials & Methods. The clinical trial included 133 MM patients aged from 31.2 to 78.2 years (the median age was 55.3 years). There were 66 female and 67 male patients. Bortezomib-based regimens as first-line treatment were administered in 133 MM patients, 74 of them received high-dose chemotherapy with melphalan and either single (n = 25), or double (n = 49) auto-HSCT as consolidation therapy in the period from 2006 to 2016. Results. The overall 5-year survival (OS) rates were 86.5 % for the auto-HSCT treated group vs. 72.9 % for the non-auto-HSCT treated group (p = 0.03); 5-year progression-free survival (PFS) rates were 64.9 vs. 39 % for the auto-HSCT and non-auto-HSCT treated groups, respectively (p = 0.0016). MM relapse/progression occurred more frequently in the non-auto-HSCT treated patients (52.5 vs. 28.4 %; p = 0.0016). In multivariate analysis the age above 60 was determined as prognostic factor of lower PFS and increase in relapse/progression rate (p = 0.004 and p = 0.04, respectively). The variant of monoclonal protein (Bence-Jones myeloma) was determined as prognostic factor of higher OS and decrease in relapse/progression rate (p = 0.02 and p = 0.04, respectively). Complete nonresponsiveness to induction therapy has proved to be an independent predictor of both poor OS and PFS (p = 0.04 and p = 0.041, respectively). 2-year bortezomib-based maintenance therapy following the auto-HSCT treatment resulted in a statistically significant improvement in 5-year PFS (67.4 vs. 60.7 %; p = 0.03) and a decrease in relapse/progression frequency (26.1 vs. 32.1 %; p = 0.05). Conclusion. High-dose chemotherapy with melphalan with subsequent auto-HSCT is an effective MM treatment strategy, and a subsequent long-term maintenance therapy results in a PFS improvement and a decrease in relapse/progression frequency

    Comparative Efficacy Analysis of Mobilization and Collection of Autologous Hematopoietic Stem Cells in Patients with Lymphoproliferative Disorders and Multiple Sclerosis

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    Aim. Comparative efficacy analysis of autologous hematopoietic stem cells (HSC) prior to auto-HSCT in patients with lymphoproliferative disorders (LPDs) and multiple sclerosis (MS). Materials & Methods. The trial included 237 patients: 103 LPD and 134 MS patients. In 225 patients HSC mobilization involved only colony-stimulating factors (CSFs), in 12 patients chemotherapy (cyclophosphamide, etoposide) was combined with CSFs. On the intended date of cytapheresis all the patients were tested for CD34+ marker expression. Сytapheresis followed in the patients with CD34+ count more than 0.01 × 106/mL. Results. In 23 (22 %) LPD patients CD34+ count was too low for auto-HSCT (‘collection failure group’). Within this group 19 patients received CSF mobilization, and 4 patients received chemotherapy + CSF. Plerixafor was administered in 5 patients, in 4 of them a repeated mobilization also failed to collect enough cells. In 80 LPD patients the number of mobilized and collected CD34+ cells was sufficient for auto-HSCT (‘collection success group’). Within this group 77 patients received auto-HSCT, 74 patients were treated with CSF mobilization, 6 patients received chemotherapy + CSF, and in 11 patients plerixafor was administered. Median total number of CD34+ cells in the ‘collection success group’ was 2.7 × 106/kg. All 134 MS patients had enough CD34+ cells for auto-HSCT. All of them received CSF mobilization. Median total number of CD34+ cells in the MS group was 2.34 × 106/kg. Potential risk factors for HSC mobilization failure in LPDs were evaluated. They included age, gender, prior radiotherapy, number of antitumor treatment lines prior to auto-HSCT, clinical response prior to auto-HSCT (complete/partial remission or stabilization), and HSC mobilization regimen. These factors with the exception of gender were not associated with mobilization failure parameters. The worst mobilization outcomes were reported in male patients. Conclusion. In 22 % of LPD patients the planned high-dose chemotherapy and auto-HSCT failed due to insufficient counts of autologous CD34+ cells in apheresis product. Male gender can be considered to be a prognostic factor of mobilization failure in LPDs

    Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

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    The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≄20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≀pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≀{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

    Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

    Observation of associated near-side and away-side long-range correlations in √sNN=5.02  TeV proton-lead collisions with the ATLAS detector

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    Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  Όb-1 of data as a function of transverse momentum (pT) and the transverse energy (ÎŁETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∌0) correlation that grows rapidly with increasing ÎŁETPb. A long-range “away-side” (Δϕ∌π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ÎŁETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ÎŁETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁥2Δϕ modulation for all ÎŁETPb ranges and particle pT

    Measurement of the cross-section of high transverse momentum vector bosons reconstructed as single jets and studies of jet substructure in pp collisions at √s = 7 TeV with the ATLAS detector

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    This paper presents a measurement of the cross-section for high transverse momentum W and Z bosons produced in pp collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of √s = 7 TeV;{\rm Te}{\rm V}andcorrespondtoanintegratedluminosityof and correspond to an integrated luminosity of 4.6\;{\rm f}{{{\rm b}}^{-1}}.ThemeasurementisperformedbyreconstructingtheboostedWorZbosonsinsinglejets.ThereconstructedjetmassisusedtoidentifytheWandZbosons,andajetsubstructuremethodbasedonenergyclusterinformationinthejetcentre−of−massframeisusedtosuppressthelargemulti−jetbackground.Thecross−sectionforeventswithahadronicallydecayingWorZboson,withtransversemomentum. The measurement is performed by reconstructing the boosted W or Z bosons in single jets. The reconstructed jet mass is used to identify the W and Z bosons, and a jet substructure method based on energy cluster information in the jet centre-of-mass frame is used to suppress the large multi-jet background. The cross-section for events with a hadronically decaying W or Z boson, with transverse momentum {{p}_{{\rm T}}}\gt 320\;{\rm Ge}{\rm V}andpseudorapidity and pseudorapidity |\eta |\lt 1.9,ismeasuredtobe, is measured to be {{\sigma }_{W+Z}}=8.5\pm 1.7$ pb and is compared to next-to-leading-order calculations. The selected events are further used to study jet grooming techniques

    Search for the neutral Higgs bosons of the minimal supersymmetric standard model in pp collisions at root s=7 TeV with the ATLAS detector

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    A search for neutral Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM) is reported. The analysis is based on a sample of proton-proton collisions at a centre-of-mass energy of 7TeV recorded with the ATLAS detector at the Large Hadron Collider. The data were recorded in 2011 and correspond to an integrated luminosity of 4.7 fb-1 to 4.8 fb-1. Higgs boson decays into oppositely-charged muon or τ lepton pairs are considered for final states requiring either the presence or absence of b-jets. No statistically significant excess over the expected background is observed and exclusion limits at the 95% confidence level are derived. The exclusion limits are for the production cross-section of a generic neutral Higgs boson, φ, as a function of the Higgs boson mass and for h/A/H production in the MSSM as a function of the parameters mA and tan ÎČ in the mhmax scenario for mA in the range of 90GeV to 500 GeV. Copyright CERN

    Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector

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    The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV

    Search for pair-produced long-lived neutral particles decaying to jets in the ATLAS hadronic calorimeter in ppcollisions at √s=8TeV

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    The ATLAS detector at the Large Hadron Collider at CERN is used to search for the decay of a scalar boson to a pair of long-lived particles, neutral under the Standard Model gauge group, in 20.3fb−1of data collected in proton–proton collisions at √s=8TeV. This search is sensitive to long-lived particles that decay to Standard Model particles producing jets at the outer edge of the ATLAS electromagnetic calorimeter or inside the hadronic calorimeter. No significant excess of events is observed. Limits are reported on the product of the scalar boson production cross section times branching ratio into long-lived neutral particles as a function of the proper lifetime of the particles. Limits are reported for boson masses from 100 GeVto 900 GeV, and a long-lived neutral particle mass from 10 GeVto 150 GeV

    Search for R-parity-violating supersymmetry in events with four or more leptons in sqrt(s) =7 TeV pp collisions with the ATLAS detector

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    A search for new phenomena in final states with four or more leptons (electrons or muons) is presented. The analysis is based on 4.7 fb−1 of s=7  TeV \sqrt{s}=7\;\mathrm{TeV} proton-proton collisions delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in two signal regions: one that requires moderate values of missing transverse momentum and another that requires large effective mass. The results are interpreted in a simplified model of R-parity-violating supersymmetry in which a 95% CL exclusion region is set for charged wino masses up to 540 GeV. In an R-parity-violating MSUGRA/CMSSM model, values of m 1/2 up to 820 GeV are excluded for 10 < tan ÎČ < 40
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