580 research outputs found

    Peripheral neuropathy after viral eradication with direct-acting antivirals in chronic HCV hepatitis: A prospective study

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    BACKGROUND: HCV‐related extra‐hepatic complications include peripheral neuropathies, with important prevalence and impact. A recent metanalysis of previous intervention trials concluded for insufficient data to support evidence‐based treatments for this complication. In this longitudinal study, we assessed for the first time prevalence and outcome of neuropathy in a cohort of patients with chronic HCV, before and after direct‐acting antiviral agent (DAA) treatment. METHOD: Ninety‐four patients (mean age 58.5 ± 9.9, infection duration 22.2 ± 6.3 years) without systemic and metabolic diseases, underwent neurological examination and electroneurography studies before (T0) and 10.4 ± 1.7 months after the end of DAA therapy (T1), and cryoglobulins (CG) assessment. Muscle strength was evaluated by Medical Research Council (MRC) score; neuropathic pain, sensory function, disability, quality of life were assessed by validated questionnaires (DN4, NPSI, SSS, INCAT and Euro‐QoL). RESULTS: At T0, sensory‐motor neuropathy was detected in 22 patients (23%), reflexes were depressed in 32 (34%) with no association with infection duration, viral load, age, CG. Neuropathic pain (DN4 ≄4) was present in 37 patients (39%). At T1, out of the 22 patients with altered electroneurography, 3 had died or developed HCC, 4 showed normal electroneurography, and nerve amplitude parameters tended to improve in the whole group. Only 11 patients (12%) had depressed reflexes and 10 (11%) DN4 ≄4 (P < .05 compared to T0). Scores for MRC, questionnaires and Euro‐QoL improved significantly (P < .05). CONCLUSION: Our study confirms the high prevalence of clinical and subclinical peripheral sensory‐motor neuropathy in patients with HCV infection and indicates improvement after eradication by DAA. These results support the need for larger intervention studies

    Pseudorapidity densities of charged particles with transverse momentum thresholds in pp collisions at √ s = 5.02 and 13 TeV

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    The pseudorapidity density of charged particles with minimum transverse momentum (pT) thresholds of 0.15, 0.5, 1, and 2 GeV/c is measured in pp collisions at the center of mass energies of √s=5.02 and 13 TeV with the ALICE detector. The study is carried out for inelastic collisions with at least one primary charged particle having a pseudorapidity (η) within 0.8pT larger than the corresponding threshold. In addition, measurements without pT-thresholds are performed for inelastic and nonsingle-diffractive events as well as for inelastic events with at least one charged particle having |η|2GeV/c), highlighting the importance of such measurements for tuning event generators. The new measurements agree within uncertainties with results from the ATLAS and CMS experiments obtained at √s=13TeV.

    Neutral to charged kaon yield fluctuations in Pb – Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV

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    We present the first measurement of event-by-event fluctuations in the kaon sector in Pb – Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV with the ALICE detector at the LHC. The robust fluctuation correlator Îœdyn_{dyn} is used to evaluate the magnitude of fluctuations of the relative yields of neutral and charged kaons, as well as the relative yields of charged kaons, as a function of collision centrality and selected kinematic ranges. While the correlator Îœdyn_{dyn}[K+^+,K−^−] exhibits a scaling approximately in inverse proportion of the charged particle multiplicity, Îœdyn_{dyn}[KS0_S^0,K±^\pm] features a significant deviation from such scaling. Within uncertainties, the value of Îœdyn_{dyn}[KS0_S^0,K±^\pm] is independent of the selected transverse momentum interval, while it exhibits a pseudorapidity dependence. The results are compared with HIJING, AMPT and EPOS–LHC predictions, and are further discussed in the context of the possible production of disoriented chiral condensates in central Pb – Pb collisions

    First study of the two-body scattering involving charm hadrons

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    This article presents the first measurement of the interaction between charm hadrons and nucleons. The two-particle momentum correlations of pD−pD^- and pˉD+\bar{p}D^+ pairs are measured by the ALICE Collaboration in high-multiplicity pp collisions at s\sqrt{s} = 13 TeV. The data are compatible with the Coulomb-only interaction hypothesis within (1.1–1.5)σ. The level of agreement slightly improves if an attractive nucleon (N)Dˉ(N)\bar{D} strong interaction is considered, in contrast to most model predictions which suggest an overall repulsive interaction. This measurement allows for the first time an estimation of the 68% confidence level interval for the isospin I=0 inverse scattering length of the NDˉN\bar{D} state f0,I=0−1f_{0,I=0}^{-1}∈[-0.4,0.9] fm−1^{-1}, assuming negligible interaction for the isospin I=1 channel

    Measurement of the angle between jet axes in Pb−-Pb collisions at sNN=5.02\sqrt{s_{\rm NN}} = 5.02 TeV

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    International audienceThis letter presents the first measurement of the angle between different jet axes (denoted as ΔR{\Delta}R) in Pb−-Pb collisions. The measurement is carried out in the 0−-10% most-central events at sNN=5.02\sqrt{s_{\rm NN}} = 5.02 TeV. Jets are assembled by clustering charged particles at midrapidity using the anti-kTk_{\rm T} algorithm with resolution parameters R=0.2R=0.2 and 0.40.4 and transverse momenta in the intervals 40<pTchjet<14040 < p_{\rm T}^{\rm ch jet} < 140 GeV/cc and 80<pTchjet<14080 < p_{\rm T}^{\rm ch jet} < 140 GeV/cc, respectively. Measurements at these low transverse momenta enhance the sensitivity to quark−-gluon plasma (QGP) effects. A comparison to models implementing various mechanisms of jet energy loss in the QGP shows that the observed narrowing of the Pb−-Pb distribution relative to pp can be explained if quark-initiated jets are more likely to emerge from the medium than gluon-initiated jets. These new measurements discard intra-jet pTp_{\rm T} broadening as described in a model calculation with the BDMPS formalism as the main mechanism of energy loss in the QGP. The data are sensitive to the angular scale at which the QGP can resolve two independent splittings, favoring mechanisms that incorporate incoherent energy loss

    First measurement of the ∣t∣|t|-dependence of incoherent J/ψ\psi photonuclear production

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    International audienceThe first measurement of the cross section for incoherent photonuclear production of J/ψ\psi vector meson as a function of the Mandelstam ∣t∣|t| variable is presented. The measurement was carried out with the ALICE detector at midrapidity, ∣y∣<0.8|y|<0.8, using ultra-peripheral collisions of Pb nuclei at a centre-of-mass energy per nucleon pair sNN=5.02\sqrt{s_{\mathrm{NN}}} = 5.02 TeV. This rapidity interval corresponds to a Bjorken-xx range (0.3(0.3−-1.4)×10−31.4)\times 10^{-3}. Cross sections are reported in five ∣t∣|t| intervals in the range 0.04<∣t∣<10.04<|t|<1~GeV2^2 and compared to the predictions of different models. Models that ignore quantum fluctuations of the gluon density in the colliding hadron predict a ∣t∣|t|-dependence of the cross section much steeper than in data. The inclusion of such fluctuations in the same models provides a better description of the data

    Charged-particle production as a function of the relative transverse activity classifier in pp, p−-Pb, and Pb−-Pb collisions at the LHC

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    International audienceMeasurements of charged-particle production in pp, p−-Pb, and Pb−-Pb collisions in the toward, away, and transverse regions with the ALICE detector are discussed. These regions are defined event-by-event relative to the azimuthal direction of the charged trigger particle, which is the reconstructed particle with the largest transverse momentum (pTtrigp_{\mathrm{T}}^{\rm trig}) in the range 8<pTtrig<158<p_{\mathrm{T}}^{\rm trig}<15 GeV/c/c. The toward and away regions contain the primary and recoil jets, respectively; both regions are accompanied by the underlying event (UE). In contrast, the transverse region perpendicular to the direction of the trigger particle is dominated by the so-called UE dynamics, and includes also contributions from initial- and final-state radiation. The relative transverse activity classifier, RT=NchT/⟹NchT⟩R_{\mathrm{T}}=N_{\mathrm{ch}}^{\mathrm{T}}/\langle N_{\mathrm{ch}}^{\mathrm{T}}\rangle, is used to group events according to their UE activity, where NchTN_{\mathrm{ch}}^{\mathrm{T}} is the charged-particle multiplicity per event in the transverse region and ⟹NchT⟩\langle N_{\mathrm{ch}}^{\mathrm{T}}\rangle is the mean value over the whole analysed sample. The energy dependence of the RTR_{\mathrm{T}} distributions in pp collisions at s=2.76\sqrt{s}=2.76, 5.02, 7, and 13 TeV is reported, exploring the Koba-Nielsen-Olesen (KNO) scaling properties of the multiplicity distributions. The first measurements of charged-particle pTp_{\rm T} spectra as a function of RTR_{\mathrm{T}} in the three azimuthal regions in pp, p−-Pb, and Pb−-Pb collisions at sNN=5.02\sqrt{s_{\rm NN}}=5.02 TeV are also reported. Data are compared with predictions obtained from the event generators PYTHIA 8 and EPOS LHC. This set of measurements is expected to contribute to the understanding of the origin of collective-like effects in small collision systems (pp and p−-Pb)

    Charm production and fragmentation fractions at midrapidity in pp collisions at s=13\sqrt{s} = 13 TeV

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    International audienceMeasurements of the production cross sections of prompt D0{\rm D^0}, D+{\rm D^+}, D∗+{\rm D^{\ast +}}, Ds+{\rm D_s^+}, Λc+{\rm \Lambda_{c}^{+}}, and Ξc+{\rm \Xi_{c}^{+}} charm hadrons at midrapidity in proton−-proton collisions at s=13\sqrt{s}=13 TeV with the ALICE detector are presented. The D-meson cross sections as a function of transverse momentum (pTp_{\rm T}) are provided with improved precision and granularity. The ratios of pTp_{\rm T}-differential meson production cross sections based on this publication and on measurements at different rapidity and collision energy provide a constraint on gluon parton distribution functions at low values of Bjorken-xx (10−5−10−410^{-5}-10^{-4}). The measurements of Λc+{\rm \Lambda_{c}^{+}} (Ξc+{\rm \Xi_{c}^{+}}) baryon production extend the measured pTp_{\rm T} intervals down to pT=0(3)p_{\rm T}=0(3)~GeV/c/c. These measurements are used to determine the charm-quark fragmentation fractions and the cc‟{\rm c\overline{c}} production cross section at midrapidity (∣y∣<0.5|y|<0.5) based on the sum of the cross sections of the weakly-decaying ground-state charm hadrons D0{\rm D^0}, D+{\rm D^+}, Ds+{\rm D_s^+}, Λc+{\rm \Lambda_{c}^{+}}, Ξc0{\rm \Xi_{c}^{0}} and, for the first time, Ξc+{\rm \Xi_{c}^{+}}, and of the strongly-decaying J/psipsi mesons. The first measurements of Ξc+{\rm \Xi_{c}^{+}} and ÎŁc0,++{\rm \Sigma_{c}^{0,++}} fragmentation fractions at midrapidity are also reported. A significantly larger fraction of charm quarks hadronising to baryons is found compared to e+^+e−^- and ep collisions. The cc‟{\rm c\overline{c}} production cross section at midrapidity is found to be at the upper bound of state-of-the-art perturbative QCD calculations

    Dielectron production in central Pb−-Pb collisions at sNN\sqrt{s_\mathrm{NN}} = 5.02 TeV

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    International audienceThe first measurement of the e+^+e−^- pair production at midrapidity and low invariant mass in central Pb−-Pb collisions at sNN=5.02\sqrt{s_{\mathrm{NN}}}=5.02 TeV at the LHC is presented. The yield of e+^+e−^- pairs is compared with a cocktail of expected hadronic decay contributions in the invariant mass (meem_{\rm ee}) and pair transverse momentum (pT,eep_{\rm T,ee}) ranges mee<3.5m_{\rm ee} < 3.5 GeV/c2/c^2 and pT,ee<8p_{\rm T,ee} < 8 GeV/c/c. For 0.18<mee<0.50.18 < m_{\rm ee} < 0.5 GeV/c2/c^2 the ratio of data to the cocktail of hadronic contributions without ρ\rho mesons amounts to 1.42±0.12 (stat.)±0.17 (syst.)±0.12 (cocktail)1.42 \pm 0.12 \ ({\rm stat.}) \pm 0.17 \ ({\rm syst.}) \pm 0.12 \ ({\rm cocktail}) and 1.44±0.12 (stat.)±0.17 (syst.)−0.21+0.17 (cocktail)1.44 \pm 0.12 \ ({\rm stat.}) \pm 0.17 \ ({\rm syst.}) ^{+0.17}_{-0.21} \ ({\rm cocktail}), including or not including medium effects in the estimation of the heavy-flavor background, respectively. It is consistent with predictions from two different models for an additional contribution of thermal e+^+e−^- pairs from the hadronic and partonic phases. In the intermediate-mass range (1.2<mee<2.61.2 < m_{\rm ee} < 2.6 GeV/c2/c^2), the pair transverse impact parameter of the e+^+e−^- pairs (DCAee_{\rm ee}) is used for the first time in Pb−-Pb collisions to separate displaced dielectrons from heavy-flavor hadron decays from a possible (thermal) contribution produced at the interaction point. The data are consistent with a suppression of e+^+e−^- pairs from cc‟{\rm c\overline{c}} and an additional prompt component. Finally, the first direct-photon measurement in the 10% most central Pb−-Pb collisions at sNN=5.02\sqrt{s_{\mathrm{NN}}}=5.02 TeV is reported via the study of virtual direct photons in the transverse momentum range 1<pT<51 < p_{\rm T} < 5 GeV/c/c. A model including prompt photons, as well as photons from the pre-equilibrium and fluid-dynamic phases, can reproduce the result, while being at the upper edge of the data uncertainties

    Dielectron production in central Pb−-Pb collisions at sNN\sqrt{s_\mathrm{NN}} = 5.02 TeV

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    International audienceThe first measurement of the e+^+e−^- pair production at midrapidity and low invariant mass in central Pb−-Pb collisions at sNN=5.02\sqrt{s_{\mathrm{NN}}}=5.02 TeV at the LHC is presented. The yield of e+^+e−^- pairs is compared with a cocktail of expected hadronic decay contributions in the invariant mass (meem_{\rm ee}) and pair transverse momentum (pT,eep_{\rm T,ee}) ranges mee<3.5m_{\rm ee} < 3.5 GeV/c2/c^2 and pT,ee<8p_{\rm T,ee} < 8 GeV/c/c. For 0.18<mee<0.50.18 < m_{\rm ee} < 0.5 GeV/c2/c^2 the ratio of data to the cocktail of hadronic contributions without ρ\rho mesons amounts to 1.42±0.12 (stat.)±0.17 (syst.)±0.12 (cocktail)1.42 \pm 0.12 \ ({\rm stat.}) \pm 0.17 \ ({\rm syst.}) \pm 0.12 \ ({\rm cocktail}) and 1.44±0.12 (stat.)±0.17 (syst.)−0.21+0.17 (cocktail)1.44 \pm 0.12 \ ({\rm stat.}) \pm 0.17 \ ({\rm syst.}) ^{+0.17}_{-0.21} \ ({\rm cocktail}), including or not including medium effects in the estimation of the heavy-flavor background, respectively. It is consistent with predictions from two different models for an additional contribution of thermal e+^+e−^- pairs from the hadronic and partonic phases. In the intermediate-mass range (1.2<mee<2.61.2 < m_{\rm ee} < 2.6 GeV/c2/c^2), the pair transverse impact parameter of the e+^+e−^- pairs (DCAee_{\rm ee}) is used for the first time in Pb−-Pb collisions to separate displaced dielectrons from heavy-flavor hadron decays from a possible (thermal) contribution produced at the interaction point. The data are consistent with a suppression of e+^+e−^- pairs from cc‟{\rm c\overline{c}} and an additional prompt component. Finally, the first direct-photon measurement in the 10% most central Pb−-Pb collisions at sNN=5.02\sqrt{s_{\mathrm{NN}}}=5.02 TeV is reported via the study of virtual direct photons in the transverse momentum range 1<pT<51 < p_{\rm T} < 5 GeV/c/c. A model including prompt photons, as well as photons from the pre-equilibrium and fluid-dynamic phases, can reproduce the result, while being at the upper edge of the data uncertainties
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