740 research outputs found

    Zika Virus Outbreak on Curaçao and Bonaire, a Report Based on Laboratory Diagnostics Data

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    Background: Zika virus (ZIKV) emerged in May 2015 in Brazil, from which it spread to many other countries in Latin America. Cases of ZIKV infection were eventually also reported in Curaçao (January 2016) and Bonaire (February 2016). Methods: In the period of 16 December 2015 until 26 April 2017, serum, EDTA-plasma or urine samples were taken at Medical Laboratory Services (MLS) from patients on Curaçao and tested in qRT-PCR at the Erasmus Medical Centre (EMC) in the Netherlands. Between 17 October 2016 until 26 April 2017 all samples of suspected ZIKV-patients collected on Curaçao, as well as on Bonaire, were tested at MLS. Paired urine and/or serum samples from patients were analyzed for ZIKV shedding kinetics, and compared in terms of sensitivity for ZIKV RNA detection. Furthermore, the age and ge

    Correlation between NS5A dimerization and hepatitis C virus replication

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    Hepatitis C virus (HCV) is the main agent of acute and chronic liver diseases leading to cirrhosis and hepatocellular carcinoma. The current standard therapy has limited efficacy and serious side effects. Thus, the development of alternate therapies is of tremendous importance. HCV NS5A (nonstructural 5A protein) is a pleiotropic protein with key roles in HCV replication and cellular signaling pathways. Here we demonstrate that NS5A dimerization occurs through Domain I (amino acids 1-240). This interaction is not mediated by nucleic acids because benzonase, RNase, and DNase treatments do not prevent NS5A-NS5A interactions. Importantly, DTT abrogates NS5A-NS5A interactions but does not affect NS5A-cyclophilin A interactions. Other reducing agents such as tris(2-carboxyethyl) phosphine and 2-mercaptoethanol also abrogate NS5A-NS5A interactions, implying that disulfide bridges may play a role in this interaction. Cyclophilin inhibitors, cyclosporine A, and alisporivir and NS5A inhibitor BMS-790052 do not block NS5A dimerization, suggesting that their antiviral effects do not involve the disruption of NS5A-NS5A interactions. Four cysteines, Cys-39, Cys-57, Cys-59, and Cys-80, are critical for dimerization. Interestingly, the four cysteines have been proposed to form a zinc-binding motif. Supporting this notion, NS5A dimerization is greatly facilitated by Zn2+ but not by Mg2+ or Mn2+. Importantly, the four cysteines are vital not only for viral replication but also critical for NS5A binding to RNA, revealing a correlation between NS5A dimerization, RNA binding, and HCV replication. Altogether our data suggest that NS5A-NS5A dimerization and/or multimerization could represent a novel target for the development of HCV therapies

    Effect of Grain Boundary Character Distribution on the Impact Toughness of 410NiMo Weld Metal

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    Grain boundary character distributions in 410NiMo weld metal were studied in the as-welded, first-stage, and second-stage postweld heat treatment (PWHT) conditions, and these were correlated with the Charpy-V impact toughness values of the material. The high impact toughness values in the weld metal in the as-welded and first-stage PWHT conditions compared to that in the second-stage condition are attributed to the higher fraction of low-energy I pound boundaries. A higher volume fraction of retained austenite and coarser martensite after second-stage PWHT accompanied by the formation of the ideal cube component in the 2-hour heat-treated specimen led to a reduction in the toughness value. A subsequent increase in the PWHT duration at 873 K (600 A degrees C) enhanced the formation of {111}aOE (c) 112 >, which impedes the adverse effect of the cubic component, resulting in an increase in the impact toughness. In addition to this, grain refinement during 4-hour PWHT in the second stage also increased the toughness of the weld metal

    Cosmological evolution of interacting dark energy in Lorentz violation

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    The cosmological evolution of an interacting scalar field model in which the scalar field interacts with dark matter, radiation, and baryon via Lorentz violation is investigated. We propose a model of interaction through the effective coupling βˉ\bar{\beta}. Using dynamical system analysis, we study the linear dynamics of an interacting model and show that the dynamics of critical points are completely controlled by two parameters. Some results can be mentioned as follows. Firstly, the sequence of radiation, the dark matter, and the scalar field dark energy exist and baryons are sub dominant. Secondly, the model also allows the possibility of having a universe in the phantom phase with constant potential. Thirdly, the effective gravitational constant varies with respect to time through βˉ\bar{\beta}. In particular, we consider a simple case where βˉ\bar{\beta} has a quadratic form and has a good agreement with the modified Λ\LambdaCDM and quintessence models. Finally, we also calculate the first post--Newtonian parameters for our model.Comment: 14 pages, published versio

    B_c meson rare decays in the light-cone quark model

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    We investigate the rare decays BcDs(1968)ˉB_c \rightarrow D_s(1968) \ell \bar{\ell} and BcDs(2317)ˉB_c\rightarrow D_s^*(2317) \ell \bar{\ell} in the framework of the light-cone quark model (LCQM). The transition form factors are calculated in the space-like region and then analytically continued to the time-like region via exponential parametrization. The branching ratios and longitudinal lepton polarization asymmetries (LPAs) for the two decays are given and compared with each other. The results are helpful to investigating the structure of BcB_c meson and to testing the unitarity of CKM quark mixing matrix. All these results can be tested in the future experiments at the LHC.Comment: 9 pages, 11 figures, version accepted for publication in EPJ

    Screening of cosmological constant for De Sitter Universe in non-local gravity, phantom-divide crossing and finite-time future singularities

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    We investigate de Sitter solutions in non-local gravity as well as in non-local gravity with Lagrange constraint multiplier. We examine a condition to avoid a ghost and discuss a screening scenario for a cosmological constant in de Sitter solutions. Furthermore, we explicitly demonstrate that three types of the finite-time future singularities can occur in non-local gravity and explore their properties. In addition, we evaluate the effective equation of state for the universe and show that the late-time accelerating universe may be effectively the quintessence, cosmological constant or phantom-like phases. In particular, it is found that there is a case in which a crossing of the phantom divide from the non-phantom (quintessence) phase to the phantom one can be realized when a finite-time future singularity occurs. Moreover, it is demonstrated that the addition of an R2R^2 term can cure the finite-time future singularities in non-local gravity. It is also suggested that in the framework of non-local gravity, adding an R2R^2 term leads to possible unification of the early-time inflation with the late-time cosmic acceleration.Comment: 42 pages, no figure, version accepted for publication in General Relativity and Gravitatio

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter
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