Effect of alkalis on the Fe oxidation state and local environment in peralkaline rhyolitic glasses

International audienceIron oxidation state and coordination geometry have been determined by Fe K-edge X-ray absorption near edge spectroscopy (XANES) for three sets of silicate glasses of peralkaline rhyolitic composition with different peralkalinity values. These compositions were chosen to investigate the effect of alkali content (and oxygen fugacity) on the Fe oxidation state. The samples were produced by means of hydrothermal vessels at 800 °C with oxygen fugacity conditions ranging from NNO-1.61 to NNO+2.96 log units. Comparison of the pre-edge peak data with those of Fe model compounds of known oxidation state and coordination number allowed determination of the Fe oxidation state and coordination number in all glasses analyzed. Within each group of samples, Fe tends to oxidize with increasing oxygen fugacity as expected. However, alkali content is shown to have a strong effect on the Fe3+/(Fe3++Fe2+) ratio at constant oxygen fugacity: this ratio varies from 0.25 to 0.55 (±0.05) for the least peralkaline series, and from 0.45 to 0.80 (±0.05) for the most peralkaline series. Moreover, pre-edge peak data clearly indicate that Fe3+ is in fourfold coordination in the most peralkaline glasses. Extrapolation of pre-edge peak data suggests the presence of both fourfold and fivefold coordination for trivalent Fe in the other two series. Divalent Fe is suggested to be mainly in fivefold coordination in all the three glass series. The presence of minor amounts of sixfold- and fourfold-coordinated Fe cannot be ruled out by XANES data alone. XANES data suggest that the amount of alkalis also affects the Fe3+ coordination environment resulting in a decrease in the average coordination numbers. Extended X-ray absorption fine structure (EXAFS) data of the most oxidized and peralkaline sample indicate that Fe3+ is in tetrahedral coordination with = 1.85 Å (±0.02). This value compares well with literature data for [4]Fe3+ in crystalline phases (e.g., in tetra-ferriphlogopite or rodolicoite) or in silicate glasses (e.g., phonolite glasses) supporting the XANES-determined coordination number obtained for the most peralkaline glasses. Calculated NBO/T ratios decrease slightly with Fe oxidation because of the higher fraction of network forming Fe, thus increasing the polymerization of the tetrahedral network

U-shaped relationship between vitamin D levels and long-term outcome in large cohort of survivors of acute myocardial infarction

Background: Previous studies in the setting of patients with acute myocardial infarction (AMI) have demonstrated that hypovitaminosis D is associated with increased mortality risk during a follow-up whose median did not exceed two years. Objective: To evaluate the impact of vitamin D levels on long-term mortality in patients with AMI. Results: In our study 477 patients with AMI were included. During a median follow-up period of 57 (IQR 53\u201364) months, 93 patients (20%) died. A non-linear U-shaped relationship between 25(OH)D levels and long-term mortality was observed; patients with vitamin D b 10 ng/mL and N30 ng/mL had higher mortality rate than those with intermediate values. After adjustment for differences in baseline features and treatment, it was con- firmed that extreme values of vitamin D (b10 or N30 ng/mL) are independent predictors of mortality with HR of 3.02 (95% CI 1.78\u20135.11). Other independent predictors of outcome were age, NYHA class at discharge, treatment with ACE inhibitors and statins. The estimated time-dependent ROC curve of the multivariable model including vitamin D showed an AUC significantly higher than the model without vitamin D: AUC 0.82 (95% CI 0.76\u20130.87) vs. 0.77 (95% CI 0.71\u20130.83), p = 0.005. Addition of vitamin D to the model that included all significant factors for mortality improved the prognostic accuracy as showed by the metrics of reclassification (NRI 0.34 (95% CI 0.14\u20130.48), p = 0.003 and IDI 0.06 (95% CI 0.01\u20130.12, p = 0.005 p = 0.03). Conclusions: We report a U-shaped relationship between vitamin D levels and long-term outcome of patients surviving AMI

The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in the Data Release 9 Spectroscopic Galaxy Sample

We present measurements of galaxy clustering from the Baryon Oscillation Spectroscopic Survey (BOSS), which is part of the Sloan Digital Sky Survey III (SDSS-III). These use the Data Release 9 (DR9) CMASS sample, which contains 264,283 massive galaxies covering 3275 square degrees with an effective redshift z=0.57 and redshift range 0.43 < z < 0.7. Assuming a concordance Lambda-CDM cosmological model, this sample covers an effective volume of 2.2 Gpc^3, and represents the largest sample of the Universe ever surveyed at this density, n = 3 x 10^-4 h^-3 Mpc^3. We measure the angle-averaged galaxy correlation function and power spectrum, including density-field reconstruction of the baryon acoustic oscillation (BAO) feature. The acoustic features are detected at a significance of 5\sigma in both the correlation function and power spectrum. Combining with the SDSS-II Luminous Red Galaxy Sample, the detection significance increases to 6.7\sigma. Fitting for the position of the acoustic features measures the distance to z=0.57 relative to the sound horizon DV /rs = 13.67 +/- 0.22 at z=0.57. Assuming a fiducial sound horizon of 153.19 Mpc, which matches cosmic microwave background constraints, this corresponds to a distance DV(z=0.57) = 2094 +/- 34 Mpc. At 1.7 per cent, this is the most precise distance constraint ever obtained from a galaxy survey. We place this result alongside previous BAO measurements in a cosmological distance ladder and find excellent agreement with the current supernova measurements. We use these distance measurements to constrain various cosmological models, finding continuing support for a flat Universe with a cosmological constant.Comment: 33 page

Intervenção da fisioterapia em doentes agudos com Covid-19 num hospital de referência: a experiência de um ano

Introdução e Objetivos: A pandemia Covid-19 lançou um desafio à intervenção do Fisioterapeuta. A evidência científica indica que a Fisioterapia tem um papel preponderante na recuperação destes doentes. Este trabalho tem como objectivo caracterizar os doentes com Covid-19 referenciados para a fisioterapia e descrever as estratégias de intervenção. Material e Métodos: Estudo descritivo de amostra consecutiva de doentes adultos com Covid-19 referenciados para fisioterapia num hospital de abril de 2020 a abril de 2021. Os doentes foram caracterizados por dados demográficos e clínicos. A funcionalidade foi classificada pela Escala de Mobilidade da UCI (EMUCI) e pela Medida de Independência Funcional (motora) (MIFm). Os dados foram analisados através de estatística descritiva. Resultados: 833 doentes foram referenciados para a fisioterapia, com idades compreendidas entre os 18 e os 100 anos (mediana de 74) e 54,7% eram homens. 88,6% internados por infeção a SARS-CoV2 e 11,4% por outros motivos, mas testaram positivo. Na UCI foram tratados 200 doentes, 36 faleceram, os restantes tiveram em média 13,6 dias de internamento e 6,7 sessões de fisioterapia. Os doentes melhoraram em média 1,3 pontos na EMUCI. Os problemas apresentados eram a dependência ventilatória e a imobilidade e a intervenção baseou-se no desmame ventilatório, controlo respiratório e estímulo da mobilidade ativa. Nas enfermarias 724 doentes beneficiaram do apoio da fisioterapia, 51 faleceram, os restantes tiveram em média 18,5 dias de internamento e 7,9 sessões de fisioterapia. Os doentes melhoraram em média 14,4 pontos na MIFm. As complicações cardiorrespiratórias e imobilidade eram os principais problemas e a intervenção da fisioterapia baseou-se em fisioterapia respiratória, incentivo e melhoria da mobilidade ativa, reeducação ao esforço e treino funcional com estratégias de conservação da energia. 347 doentes tiveram alta para a residência habitual, 204 transferidos para outra unidade hospitalar, 46 para a RNCCI, 34 para lar e 6 para outros destinos. Conclusões: O apoio da fisioterapia foi valorizado pela equipa multidisciplinar e pelos doentes contribuindo para a melhoria funcional dos doentes com Covid-19.info:eu-repo/semantics/publishedVersio

Cytoplasmic Polyadenylation Element Binding Protein Deficiency Stimulates PTEN and Stat3 mRNA Translation and Induces Hepatic Insulin Resistance

The cytoplasmic polyadenylation element binding protein CPEB1 (CPEB) regulates germ cell development, synaptic plasticity, and cellular senescence. A microarray analysis of mRNAs regulated by CPEB unexpectedly showed that several encoded proteins are involved in insulin signaling. An investigation of Cpeb1 knockout mice revealed that the expression of two particular negative regulators of insulin action, PTEN and Stat3, were aberrantly increased. Insulin signaling to Akt was attenuated in livers of CPEB–deficient mice, suggesting that they might be defective in regulating glucose homeostasis. Indeed, when the Cpeb1 knockout mice were fed a high-fat diet, their livers became insulin-resistant. Analysis of HepG2 cells, a human liver cell line, depleted of CPEB demonstrated that this protein directly regulates the translation of PTEN and Stat3 mRNAs. Our results show that CPEB regulated translation is a key process involved in insulin signaling

Neutralising antibodies for West Nile virus in horses from Brazilian Pantanal

Despite evidence of West Nile virus (WNV) activity in Colombia, Venezuela and Argentina, this virus has not been reported in most South American countries. In February 2009, we commenced an investigation for WNV in mosquitoes, horses and caimans from the Pantanal, Central-West Brazil. The sera of 168 horses and 30 caimans were initially tested using a flaviviruses-specific epitope-blocking enzyme-linked immunosorbent assay (blocking ELISA) for the detection of flavivirus-reactive antibodies. The seropositive samples were further tested using a plaque-reduction neutralisation test (PRNT90) for WNV and its most closely-related flaviviruses that circulate in Brazil to confirm the detection of specific virus-neutralising antibodies. Of the 93 (55.4%) blocking ELISA-seropositive horse serum samples, five (3%) were seropositive for WNV, nine (5.4%) were seropositive for St. Louis encephalitis virus, 18 (10.7%) were seropositive for Ilheus virus, three (1.8%) were seropositive for Cacipacore virus and none were seropositive for Rocio virus using PRNT90, with a criteria of > four-fold antibody titre difference. All caimans were negative for flaviviruses-specific antibodies using the blocking ELISA. No virus genome was detected from caiman blood or mosquito samples. The present study is the first report of confirmed serological evidence of WNV activity in Brazil