824 research outputs found

    Electrodynamics of the vortex lattice in untwinned YBaCuO by complex impedance measurements

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    We report complex impedance measurements in an untwinned YBaCuO crystal. Our broad frequency range covers both the quasi static response and the resistive response of the vortex lattice. It allow us to characterize the irreversibility line without the need of any frequency dependent pinning parameters. We confirm the validity of the two modes model of vortex dynamic, and extract both the surface critical current and the flux flow resistivity around the first order transition TmT_{m}. This latter is identified by the abrupt loss of pinning and by an unexpected step of ρff(T)\rho_{ff}(T) at TmT_{m}.Comment: accepted for publication in EPJ

    The neutron time-of-flight facility n-TOF at CERN: Phase II

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    Neutron-induced reactions are studied at the neutron time-of-flight facility n-TOF at CERN. The facility uses 6∼ns wide pulses of 20 GeV/c protons impinging on a lead spallation target. The large neutron energy range and the high instantaneous neutron flux combined with high resolution are among the key characteristics of the facility. After a first phase of data taking during the period 2001-2004, the facility has been refurbished with an upgraded spallation target and cooling system for a second phase of data taking which started in 2009. Since 2010, the experimental area at 185 m where the neutron beam arrives, has been modified into a worksector of type A, allowing the extension of the physics program to include neutron-induced reactions on radioactive isotopes

    Assimilation to the Unmarked

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    Steel, JC ORCiD: 0000-0003-3608-7542Intravitreal injection of recombinant adeno-associated virus (AAV) might be an alternative approach for retinal gene therapy for certain applications. Although the jelly-like substance consists mainly of water, anti-viral antibodies against various viruses such as HIV or HSV have been observed in the human vitreous and anti-AAV neutralising antibodies (NAbs) in rhesus macaque vitreous have also been detected. In this study, the human vitreous humour was obtained from 70 post mortem unpaired eye cups and 10 paired eye cups from the Queensland Eye Bank. The transduction efficiency of 1-3 · 108 vcg of recombinant AAV-2, -5, -6 and -8 expressing secreted nanoluciferase was measured following transduction of ARPE-19 and Cos-7 cells at vitreous humour dilutions from 1:2 to 1:10 000. At vitreous humour dilution of 1:2, a reduction in transduction of over 50% was observed for AAV2 in 50.5% of samples and for AAV6 in 66.2% of samples. Only 23.2% of tested samples showed similar reduction in transduction efficiency for AAV5, and for AAV8 only 2.5% of samples inhibited transduction by 50% at 1:2 dilution. Differences in serum antibody levels have been previously observed in a similar Australian population, but low transduction inhibition at vitreous humour dilutions of 1:100 suggests that the concentration of NAbs within the vitreous humour is lower than in human serum. In addition, this study also reported an increase in transduction efficiency for AAV8 at highest vitreous humour concentrations, supporting previous reports that human albumin can increase AAV transduction but only in some serotypes

    Correction: Detection of Chlamydia in the peripheral blood cells of normal donors using in vitro culture, immunofluorescence microscopy and flow cytometry techniques

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    BACKGROUND: Chlamydia trachomatis (Ct) and Chlamydia pneumoniae (Cp) are medically significant infectious agents associated with various chronic human pathologies. Nevertheless, specific roles in disease progression or initiation are incompletely defined. Both pathogens infect established cell lines in vitro and polymerase chain reaction (PCR) has detected Chlamydia DNA in various clinical specimens as well as in normal donor peripheral blood monocytes (PBMC). However, Chlamydia infection of other blood cell types, quantification of Chlamydia infected cells in peripheral blood and transmission of this infection in vitro have not been examined. METHODS: Cp specific titers were assessed for sera from 459 normal human donor blood (NBD) samples. Isolated white blood cells (WBC) were assayed by in vitro culture to evaluate infection transmission of blood cell borne chlamydiae. Smears of fresh blood samples (FB) were dual immunostained for microscopic identification of Chlamydia-infected cell types and aliquots also assessed using Flow Cytometry (FC). RESULTS: ELISA demonstrated that 219 (47.7%) of the NBD samples exhibit elevated anti-Cp antibody titers. Imunofluorescence microscopy of smears demonstrated 113 (24.6%) of samples contained intracellular Chlamydia and monoclonals to specific CD markers showed that in vivo infection of neutrophil and eosinophil/basophil cells as well as monocytes occurs. In vitro culture established WBCs of 114 (24.8%) of the NBD samples harbored infectious chlamydiae, clinically a potentially source of transmission, FC demonstrated both Chlamydia infected and uninfected cells can be readily identified and quantified. CONCLUSION: NBD can harbor infected neutrophils, eosinophil/basophils and monocytes. The chlamydiae are infectious in vitro, and both total, and cell type specific Chlamydia carriage is quantifiable by FC

    Measurement of the 70Ge(n,γ) cross section up to 300 keV at the CERN n_TOF facility

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    Neutron capture data on intermediate mass nuclei are of key importance to nucleosynthesis in the weak component of the slow neutron capture processes, which occurs in massive stars. The (n,γ) cross section on 70Ge, which is mainly produced in the s process, was measured at the neutron time-of-flight facility n_TOF at CERN. Resonance capture kernels were determined up to 40 keV neutron energy and average cross sections up to 300 keV. Stellar cross sections were calculated from kT =5 keV tokT =100 keV and are in very good agreement with a previous measurement by Walter and Beer (1985) and recent evaluations. Average cross sectionsareinagreementwithWalterandBeer(1985)overmostoftheneutronenergyrangecovered,whilethey aresystematicallysmallerforneutronenergiesabove150keV.Wehavecalculatedisotopicabundancesproduced in s-process environments in a 25 solar mass star for two initial metallicities (below solar and close to solar). While the low metallicity model reproduces best the solar system germanium isotopic abundances, the close to solar model shows a good global match to solar system abundances in the range of mass numbers A=60–80.Austrian Science Fund J3503Adolf Messer Foundation ST/M006085/1European Research Council ERC2015-StGCroatian Science Foundation IP-2018-01-857

    Mental health of Czech university psychology students : negative mental health attitudes, mental health shame and self-compassion

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    High rates of mental health problems are a growing concern in Czech higher education, negatively impacting students’ performance and wellbeing. Despite the serious nature of poor mental health, students often do not seek help because of negative attitudes and shame over mental health problems. Recent mental health research reports self-compassion is strongly associated with better mental health and reduced shame. However, relationships between those constructs remain to be evaluated among Czech students. This study aims to appraise the relationships between mental health problems, negative mental health attitudes, mental health shame, and self-compassion in this population. An opportunity sample of 119 psychology students from a Czech university completed questionnaires regarding these constructs. Correlation, regression, and path analyses were conducted. Mental health problems were positively associated with negative mental health attitudes and shame, and negatively associated with self-compassion. Self-compassion negatively predicted mental health problems, while negative attitudes and shame did not. Last, self-compassion fully mediated the negative attitudes-mental health problems relationship, and partially mediated the shame-mental health problems relationship. Findings suggest self-compassion is essential for mental health in Czech students and associated with negative mental health attitudes and mental health shame. Czech universities can benefit from incorporating self-compassion training into their curricula to protect students’ mental health

    Radiative neutron capture cross-section measurement of ge isotopes at n_TOF CERN facility and its importance for stellar nucleosynthesis

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    This manuscript summarizes the results of radiative neutron capture cross-section measurements on two stable germanium isotopes, 70Ge and 73Ge. Experiments were performed at the n_TOF facility at CERN via the time-of-flight technique, over a wide neutron energy range, for all stable germanium isotopes (70,72,73,74, and 76). Results for 70Ge [Phys. Rev. C 100, 045804 (2019)] and 73Ge [Phys. Lett. B 790, 458 (2019)] are already published. In the field of nuclear structure, such measurements allow to study excited levels close to the neutron binding energy and to obtain information on nuclear properties. In stellar nucleosynthesis research, neutron induced reactions on germanium are of importance for nucleosynthesis in the weak component of the slow neutron capture processes. © 2021 Polish Academy of Sciences. All rights reserved.Austrian Science Fund FWFUK Science and Facilities Council ST/M006085/1European Research Council (ERC) ERC-2015-StG No. 677497National Science Center. Poland UMO2016/22/M/ST2/00183MSMT of the Czech Republic IP-2018-01-8570Croatian Science Foundation IP-2018-01-857
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