36 research outputs found

    Monazite-type SrCrO4 under compression

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    We report a high-pressure study of monoclinic monazite-type SrCrO4 up to 26 GPa. Therein we combined x-ray diffraction, Raman, and optical-absorption measurements with ab initio calculations, to find a pressure-induced structural phase transition of SrCrO4 near 8–9 GPa. Evidence of a second phase transition was observed at 10–13 GPa. The crystal structures of the high-pressure phases were assigned to the tetragonal scheelite-type and monoclinic AgMnO4-type structures. Both transitions produce drastic changes in the electronic band gap and phonon spectrum of SrCrO4. We determined the pressure evolution of the band gap for the low- and high-pressure phases as well as the frequencies and pressure dependencies of the Raman-active modes. In all three phases most Raman modes harden under compression, however the presence of low-frequency modes which gradually soften is also detected. In monazite-type SrCrO4, the band gap blueshifts under compression, but the transition to the scheelite phase causes an abrupt decrease of the band gap in SrCrO4. Calculations showed good agreement with experiments and were used to better understand the experimental results. From x-ray-diffraction studies and calculations we determined the pressure dependence of the unit-cell parameters of the different phases and their ambient-temperature equations of state. The results are compared with the high-pressure behavior of other monazites, in particular PbCrO4. A comparison of the high-pressure behavior of the electronic properties of SrCrO4 (SrWO4) and PbCrO4 (PbWO4) will also be made. Finally, the possible occurrence of a third structural phase transition is discussed

    Recommendations for the introduction of metagenomic next-generation sequencing in clinical virology, part II: bioinformatic analysis and reporting

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    Metagenomic next-generation sequencing (mNGS) is an untargeted technique for determination of microbial DNA/RNA sequences in a variety of sample types from patients with infectious syndromes. mNGS is still in its early stages of broader translation into clinical applications. To further support the development, implementation, optimization and standardization of mNGS procedures for virus diagnostics, the European Society for Clinical Virology (ESCV) Network on Next-Generation Sequencing (ENNGS) has been established. The aim of ENNGS is to bring together professionals involved in mNGS for viral diagnostics to share methodologies and experiences, and to develop application guidelines. Following the ENNGS publication Recommendations for the introduction of mNGS in clinical virology, part I: wet lab procedure in this journal, the current manuscript aims to provide practical recommendations for the bioinformatic analysis of mNGS data and reporting of results to clinicians.Molecular basis of virus replication, viral pathogenesis and antiviral strategie

    Bacteremic pneumococcal pneumonia : clinical outcomes and preliminary results of inflammatory response

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    Purpose: Further examination of clinical outcomes and inflammatory response of bacteremic pneumococcal community-acquired pneumonia (CAP) is of great interest to enhance the care of patients with pneumococcal CAP. Methods: This is a secondary analysis of the Community Acquired Pneumonia Organization (CAPO) to compare the time to clinical stability (TCS), length of hospital stay (LOS), and in-hospital mortality of hospitalized pneumococcal CAP patients with and without bacteremia. To measure the effect of bacteremia in pneumococcal CAP patients on outcomes, we modeled all-cause in-hospital mortality using a Poisson regression model, and TCS and LOS using Cox proportional hazards models. Adjusted multivariate regression models were also used to predict the probability of occurrence of each of the study outcomes. To investigate the inflammatory response, we measured the plasma levels of pro- and anti-inflammatory cytokines [tumor necrosis factor (TNF)-\u3b1, interleukin (IL)-1r\u3b1, IL-6, IL-8, IL-10], inflammatory biomarkers [C-reactive protein (CRP), pro-calcitonin (PCT), and B-type natriuretic peptide (BNP)], and peripheral blood neutrophil responses in 10 patients, 4 bacteremic and 6 non-bacteremic pneumococcal CAP, upon admission and every other day during the first 6 days of hospitalization. Functional data were presented as median and standard error of the median (SEM); due to small number of samples no statistical comparisons were performed between groups. Results: From 833 pneumococcal CAP patients, 394 patients (47 %) were bacteremic. Bacteremic pneumococcal CAP were less likely to reach TCS with an adjusted hazard ratio (AHR) of 0.82 (95 % CI 0.69\u20130.97; p = 0.02) and had higher in-hospital mortality with an AHR of 1.63 (95 % CI 1.06\u20132.50, p = 0.026). Bacteremic pneumococcal CAP patients had a longer LOS than non-bacteremic pneumococcal CAP (p < 0.003). Higher plasma levels of CRP, PCT, and BNP were found in bacteremic than in non-bacteremic patients. The bacteremic group had consistently higher plasma levels of both pro- and anti-inflammatory cytokines. The blood neutrophil functional responses were similar in both groups of patients. Conclusions: Bacteremic pneumococcal CAP patients were significantly associated with higher in-hospital mortality, lower TCS, and longer LOS. HIV-infected patients showed a greater mortality which was not statistically significant. Bacteremic pneumococcal CAP patients had higher levels of biomarkers and systemic cytokines
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