142 research outputs found
Coherent X-ray Scattering Reveals Nanoscale Fluctuations in Hydrated Proteins
Hydrated proteins undergo a transition in the deeply supercooled regime,
which is attributed to rapid changes in hydration water and protein structural
dynamics. Here, we investigate the nanoscale stress relaxation in hydrated
lysozyme proteins stimulated and probed by X-ray Photon Correlation
Spectroscopy (XPCS). This approach allows us to access the nanoscale dynamic
response in the deeply supercooled regime (T = 180 K) which is typically not
accessible through equilibrium methods. The relaxation time constants exhibit
Arrhenius temperature dependence upon cooling with a minimum in the
Kohlrausch-Williams-Watts exponent at T = 227 K. The observed minimum is
attributed to an increase in dynamical heterogeneity, which coincides with
enhanced fluctuations observed in the two-time correlation functions and a
maximum in the dynamic susceptibility quantified by the normalised variance
. Our study provides new insights into X-ray stimulated stress
relaxation and the underlying mechanisms behind spatio-temporal fluctuations in
biological granular materials
an individual participant data meta-analysis
Background The impact of neuraminidase inhibitors (NAIs) on influenza-related
pneumonia (IRP) is not established. Our objective was to investigate the
association between NAI treatment and IRP incidence and outcomes in patients
hospitalised with A(H1N1)pdm09 virus infection. Methods A worldwide meta-
analysis of individual participant data from 20 634 hospitalised patients with
laboratory-confirmed A(H1N1)pdm09 (n = 20 021) or clinically diagnosed (n =
613) ‘pandemic influenza’. The primary outcome was radiologically confirmed
IRP. Odds ratios (OR) were estimated using generalised linear mixed modelling,
adjusting for NAI treatment propensity, antibiotics and corticosteroids.
Results Of 20 634 included participants, 5978 (29·0%) had IRP; conversely,
3349 (16·2%) had confirmed the absence of radiographic pneumonia (the
comparator). Early NAI treatment (within 2 days of symptom onset) versus no
NAI was not significantly associated with IRP [adj. OR 0·83 (95% CI 0·64–1·06;
P = 0·136)]. Among the 5978 patients with IRP, early NAI treatment versus none
did not impact on mortality [adj. OR = 0·72 (0·44–1·17; P = 0·180)] or
likelihood of requiring ventilatory support [adj. OR = 1·17 (0·71–1·92; P =
0·537)], but early treatment versus later significantly reduced mortality
[adj. OR = 0·70 (0·55–0·88; P = 0·003)] and likelihood of requiring
ventilatory support [adj. OR = 0·68 (0·54–0·85; P = 0·001)]. Conclusions Early
NAI treatment of patients hospitalised with A(H1N1)pdm09 virus infection
versus no treatment did not reduce the likelihood of IRP. However, in patients
who developed IRP, early NAI treatment versus later reduced the likelihood of
mortality and needing ventilatory support
Impact of neuraminidase inhibitors on influenza A(H1N1)pdm09‐related pneumonia: an individual participant data meta‐analysis
BACKGROUND: The impact of neuraminidase inhibitors (NAIs) on influenza‐related pneumonia (IRP) is not established. Our objective was to investigate the association between NAI treatment and IRP incidence and outcomes in patients hospitalised with A(H1N1)pdm09 virus infection.
METHODS: A worldwide meta‐analysis of individual participant data from 20 634 hospitalised patients with laboratory‐confirmed A(H1N1)pdm09 (n = 20 021) or clinically diagnosed (n = 613) ‘pandemic influenza’. The primary outcome was radiologically confirmed IRP. Odds ratios (OR) were estimated using generalised linear mixed modelling, adjusting for NAI treatment propensity, antibiotics and corticosteroids.
RESULTS: Of 20 634 included participants, 5978 (29·0%) had IRP; conversely, 3349 (16·2%) had confirmed the absence of radiographic pneumonia (the comparator). Early NAI treatment (within 2 days of symptom onset) versus no NAI was not significantly associated with IRP [adj. OR 0·83 (95% CI 0·64–1·06; P = 0·136)]. Among the 5978 patients with IRP, early NAI treatment versus none did not impact on mortality [adj. OR = 0·72 (0·44–1·17; P = 0·180)] or likelihood of requiring ventilatory support [adj. OR = 1·17 (0·71–1·92; P = 0·537)], but early treatment versus later significantly reduced mortality [adj. OR = 0·70 (0·55–0·88; P = 0·003)] and likelihood of requiring ventilatory support [adj. OR = 0·68 (0·54–0·85; P = 0·001)].
CONCLUSIONS: Early NAI treatment of patients hospitalised with A(H1N1)pdm09 virus infection versus no treatment did not reduce the likelihood of IRP. However, in patients who developed IRP, early NAI treatment versus later reduced the likelihood of mortality and needing ventilatory support
Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector
A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
Neuraminidase Inhibitors and Hospital Length of Stay: A Meta-analysis of Individual Participant Data to Determine Treatment Effectiveness Among Patients Hospitalized With Nonfatal 2009 Pandemic Influenza A(H1N1) Virus Infection
© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: [email protected]. BACKGROUND: The effect of neuraminidase inhibitor (NAI) treatment on length of stay (LoS) in patients hospitalized with influenza is unclear. METHODS: We conducted a one-stage individual participant data (IPD) meta-analysis exploring the association between NAI treatment and LoS in patients hospitalized with 2009 influenza A(H1N1) virus (A[H1N1]pdm09) infection. Using mixed-effects negative binomial regression and adjusting for the propensity to receive NAI, antibiotic, and corticosteroid treatment, we calculated incidence rate ratios (IRRs) and 95% confidence intervals (CIs). Patients with a LoS o
Angular analysis of the B-0 -> K*(0) e(+) e(-) decay in the low-q(2) region
An angular analysis of the decay is performed using a data sample, corresponding to an integrated luminosity of 3.0 {\mbox{fb}^{-1}}, collected by the LHCb experiment in collisions at centre-of-mass energies of 7 and 8 TeV during 2011 and 2012. For the first time several observables are measured in the dielectron mass squared () interval between 0.002 and 1.120. The angular observables and which are related to the polarisation and to the lepton forward-backward asymmetry, are measured to be and , where the first uncertainty is statistical and the second systematic. The angular observables and which are sensitive to the photon polarisation in this range, are found to be and . The results are consistent with Standard Model predictions.An angular analysis of the B → K^{*}^{0} e e decay is performed using a data sample, corresponding to an integrated luminosity of 3.0 fb, collected by the LHCb experiment in pp collisions at centre-of-mass energies of 7 and 8 TeV during 2011 and 2012. For the first time several observables are measured in the dielectron mass squared (q) interval between 0.002 and 1.120 GeV /c. The angular observables F and A which are related to the K^{*}^{0} polarisation and to the lepton forward-backward asymmetry, are measured to be F = 0.16 ± 0.06 ± 0.03 and A = 0.10 ± 0.18 ± 0.05, where the first uncertainty is statistical and the second systematic. The angular observables A and A which are sensitive to the photon polarisation in this q range, are found to be A = − 0.23 ± 0.23 ± 0.05 and A = 0.14 ± 0.22 ± 0.05. The results are consistent with Standard Model predictions.An angular analysis of the decay is performed using a data sample, corresponding to an integrated luminosity of 3.0 {\mbox{fb}^{-1}}, collected by the LHCb experiment in collisions at centre-of-mass energies of 7 and 8 TeV during 2011 and 2012. For the first time several observables are measured in the dielectron mass squared () interval between 0.002 and 1.120. The angular observables and which are related to the polarisation and to the lepton forward-backward asymmetry, are measured to be and , where the first uncertainty is statistical and the second systematic. The angular observables and which are sensitive to the photon polarisation in this range, are found to be and . The results are consistent with Standard Model predictions
Observation of the B0 → ρ0ρ0 decay from an amplitude analysis of B0 → (π+π−)(π+π−) decays
Proton–proton collision data recorded in 2011 and 2012 by the LHCb experiment, corresponding to an integrated luminosity of 3.0 fb−1 , are analysed to search for the charmless B0→ρ0ρ0 decay. More than 600 B0→(π+π−)(π+π−) signal decays are selected and used to perform an amplitude analysis, under the assumption of no CP violation in the decay, from which the B0→ρ0ρ0 decay is observed for the first time with 7.1 standard deviations significance. The fraction of B0→ρ0ρ0 decays yielding a longitudinally polarised final state is measured to be fL=0.745−0.058+0.048(stat)±0.034(syst) . The B0→ρ0ρ0 branching fraction, using the B0→ϕK⁎(892)0 decay as reference, is also reported as B(B0→ρ0ρ0)=(0.94±0.17(stat)±0.09(syst)±0.06(BF))×10−6
Measurement of the (eta c)(1S) production cross-section in proton-proton collisions via the decay (eta c)(1S) -> p(p)over-bar
The production of the state in proton-proton collisions is probed via its decay to the final state with the LHCb detector, in the rapidity range GeV/c. The cross-section for prompt production of mesons relative to the prompt cross-section is measured, for the first time, to be at a centre-of-mass energy TeV using data corresponding to an integrated luminosity of 0.7 fb, and at TeV using 2.0 fb. The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the and decays to the final state. In addition, the inclusive branching fraction of -hadron decays into mesons is measured, for the first time, to be , where the third uncertainty includes also the uncertainty on the inclusive branching fraction from -hadron decays. The difference between the and meson masses is determined to be MeV/c.The production of the state in proton-proton collisions is probed via its decay to the final state with the LHCb detector, in the rapidity range . The cross-section for prompt production of mesons relative to the prompt cross-section is measured, for the first time, to be at a centre-of-mass energy using data corresponding to an integrated luminosity of 0.7 fb , and at using 2.0 fb . The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the and decays to the final state. In addition, the inclusive branching fraction of -hadron decays into mesons is measured, for the first time, to be , where the third uncertainty includes also the uncertainty on the inclusive branching fraction from -hadron decays. The difference between the and meson masses is determined to be .The production of the state in proton-proton collisions is probed via its decay to the final state with the LHCb detector, in the rapidity range GeV/c. The cross-section for prompt production of mesons relative to the prompt cross-section is measured, for the first time, to be at a centre-of-mass energy TeV using data corresponding to an integrated luminosity of 0.7 fb, and at TeV using 2.0 fb. The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the and decays to the final state. In addition, the inclusive branching fraction of -hadron decays into mesons is measured, for the first time, to be , where the third uncertainty includes also the uncertainty on the inclusive branching fraction from -hadron decays. The difference between the and meson masses is determined to be MeV/c
A study of CP violation in B-+/- -> DK +/- and B-+/- -> D pi(+/-) decays with D -> (KSK +/-)-K-0 pi(-/+) final states
A first study of CP violation in the decay modes and , where labels a or meson and labels a or meson, is performed. The analysis uses the LHCb data set collected in collisions, corresponding to an integrated luminosity of 3 fb. The analysis is sensitive to the CP-violating CKM phase through seven observables: one charge asymmetry in each of the four modes and three ratios of the charge-integrated yields. The results are consistent with measurements of using other decay modes
Study of the rare B-s(0) and B-0 decays into the pi(+) pi(-) mu(+) mu(-) final state
A search for the rare decays and is performed in a data set corresponding to an integrated luminosity of 3.0 fb collected by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV. Decay candidates with pion pairs that have invariant mass in the range 0.5-1.3 GeV/ and with muon pairs that do not originate from a resonance are considered. The first observation of the decay and the first evidence of the decay are obtained and the branching fractions are measured to be and , where the third uncertainty is due to the branching fraction of the decay , used as a normalisation.A search for the rare decays Bs0→π+π−μ+μ− and B0→π+π−μ+μ− is performed in a data set corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb detector in proton–proton collisions at centre-of-mass energies of 7 and 8 TeV . Decay candidates with pion pairs that have invariant mass in the range 0.5–1.3 GeV/c2 and with muon pairs that do not originate from a resonance are considered. The first observation of the decay Bs0→π+π−μ+μ− and the first evidence of the decay B0→π+π−μ+μ− are obtained and the branching fractions, restricted to the dipion-mass range considered, are measured to be B(Bs0→π+π−μ+μ−)=(8.6±1.5 (stat)±0.7 (syst)±0.7(norm))×10−8 and B(B0→π+π−μ+μ−)=(2.11±0.51(stat)±0.15(syst)±0.16(norm))×10−8 , where the third uncertainty is due to the branching fraction of the decay B0→J/ψ(→μ+μ−)K⁎(892)0(→K+π−) , used as a normalisation.A search for the rare decays Bs0→π+π−μ+μ− and B0→π+π−μ+μ− is performed in a data set corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb detector in proton–proton collisions at centre-of-mass energies of 7 and 8 TeV . Decay candidates with pion pairs that have invariant mass in the range 0.5–1.3 GeV/c2 and with muon pairs that do not originate from a resonance are considered. The first observation of the decay Bs0→π+π−μ+μ− and the first evidence of the decay B0→π+π−μ+μ− are obtained and the branching fractions, restricted to the dipion-mass range considered, are measured to be B(Bs0→π+π−μ+μ−)=(8.6±1.5 (stat)±0.7 (syst)±0.7(norm))×10−8 and B(B0→π+π−μ+μ−)=(2.11±0.51(stat)±0.15(syst)±0.16(norm))×10−8 , where the third uncertainty is due to the branching fraction of the decay B0→J/ψ(→μ+μ−)K⁎(892)0(→K+π−) , used as a normalisation.A search for the rare decays and is performed in a data set corresponding to an integrated luminosity of 3.0 fb collected by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV. Decay candidates with pion pairs that have invariant mass in the range 0.5-1.3 GeV/ and with muon pairs that do not originate from a resonance are considered. The first observation of the decay and the first evidence of the decay are obtained and the branching fractions, restricted to the dipion-mass range considered, are measured to be and , where the third uncertainty is due to the branching fraction of the decay , used as a normalisation
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