207 research outputs found

    Zn supported on Zr modified mesoporous SBA-15 as sorbents of pollutant precursors contained in fossil fuels: Si/Zr ratio effect

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    The adsption processes have become an additional alternative to hydrotreatment processes of oilderived middle distillates. The crucial point is the type of adsorbent employed. SBA-15 mesoporous materials were used to adsorb quinoline (Q) and dibenzothiophene (DBT) as N- and S-containing model species, espectively, contained in a model mixture mimicking middle distillates. Q and DBT in dodecane solutions (50-250 ppm and 500 ppm, respectively) were used to that end. In order to improve the adsorption properties, SBA-15 was modified, incorporating zirconium at Si/Zr weight ratios of 5, 16, 60, and 150. At those ratios, Q was adsorbed preferably, whereas DBT was removed only below 10%. To increase the amount of S dsorbed, Zn was incorporated at 2 wt. %. At 250 ppm (sol. concentration) of N, the amount adsorbed of Q and DBT on the material without Zn (Si/Zr=5) was 1.51 and 0.02 mmolgads -1, respectively. The results were notably different when Zn was incorporated in adsorbents. In these case, amounts of adsorbed Q and DBT were 2.2 and 1.3 mmolgads -1, respectively, showing that metal sites are essential to adsorb DBT

    Molecular epidemiological analysis of Mycoplasma genitalium shows low prevalence of azithromycin resistance and a well-established epidemic in South Africa

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    OBJECTIVES: Macrolide resistance in Mycoplasma genitalium is emerging globally. There is paucity of data from sub-Saharan Africa where syndromic management is used to treat sexually transmitted infections (STIs). We conducted a molecular epidemiological study to determine the prevalence of azithromycin resistance and epidemic diversity of M. genitalium infections in South Africa. METHODS : We analysed 90 M. genitalium-positive specimens that had been collected consecutively from men and women (50% symptomatic) from geographically diverse communities across the northern part of South Africa between 2015 and 2019. Melting curve analysis followed by targeted sequencing of the 23S rRNA gene was performed to detect azithromycin resistance. Molecular typing was done through single nucleotide polymorphism (SNP) analysis of the MG191 gene and short tandem repeats (STR) assessment of the MG309 gene. An overview of all published M. genitalium sequence types was generated and novel sequence types identified in this study were allocated numbers accordingly. RESULTS : Azithromycin resistance was detected in 1/90 M. genitalium-positive specimens (1.1%; 95% CI 0% to 3.3%) as conferred by A2071G mutation; this strain also harboured a C234T mutation in the parC gene with wild type gyrA gene. SNP typing and STR assessment was successful in 38/90 specimens (42%) and showed a genetically diverse epidemic, without geographic clustering, with eight novel sequence types identified. CONCLUSION : This is the first study that determines resistance in M. genitalium infection since introduction of azithromycin in the syndromic management regimen for STIs in South Africa in 2015. Despite a well-established epidemic, azithromycin-resistant M. genitalium infection is still uncommon in the public healthcare sector. However, it has the potential to undermine the effectiveness of syndromic management. Introduction of molecular diagnostics and continuous surveillance are warranted for early detection emergence of resistance.The Netherlands Enterprise Agency (Rijksdienst voor Ondernemend Nederland) and by the Eunice Kennedy Shriver National Institute of Child Health & Human Development, U.S. National Institute of Health.http://sti.bmj.comhj2022Medical Microbiolog

    Consenso colombiano de atención, diagnóstico y manejo de la infección por SARS-COV-2/COVID-19 en establecimientos de atención de la salud Recomendaciones basadas en consenso de expertos e informadas en la evidencia

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    The “Asociación Colombiana de Infectología” (ACIN) and the “Instituto de Evaluación de Nuevas Tecnologías de la Salud” (IETS) created a task force to develop recommendations for Covid 19 health care diagnosis, management and treatment informed, and based, on evidence. Theses reccomendations are addressed to the health personnel on the Colombian context of health services. © 2020 Asociacion Colombiana de Infectologia. All rights reserved

    Estimation of Genetic Relationships Between Individuals Across Cohorts and Platforms: Application to Childhood Height

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    Combining genotype data across cohorts increases power to estimate the heritability due to common single nucleotide polymorphisms (SNPs), based on analyzing a Genetic Relationship Matrix (GRM). However, the combination of SNP data across multiple cohorts may lead to stratification, when for example, different genotyping platforms are used. In the current study, we address issues of combining SNP data from different cohorts, the Netherlands Twin Register (NTR) and the Generation R (GENR) study. Both cohorts include children of Northern European Dutch background (N = 3102 + 2826, respectively) who were genotyped on different platforms. We explore imputation and phasing as a tool and compare three GRM-building strategies, when data from two cohorts are (1) just comb

    Large-scale association analyses identify host factors influencing human gut microbiome composition

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    To study the effect of host genetics on gut microbiome composition, the MiBioGen consortium curated and analyzed genome-wide genotypes and 16S fecal microbiome data from 18,340 individuals (24 cohorts). Microbial composition showed high variability across cohorts: only 9 of 410 genera were detected in more than 95% of samples. A genome-wide association study of host genetic variation regarding microbial taxa identified 31 loci affecting the microbiome at a genome-wide significant (P < 5 x 10(-8)) threshold. One locus, the lactase (LCT) gene locus, reached study-wide significance (genome-wide association study signal: P = 1.28 x 10(-20)), and it showed an age-dependent association with Bifidobacterium abundance. Other associations were suggestive (1.95 x 10(-10) < P < 5 x 10(-8)) but enriched for taxa showing high heritability and for genes expressed in the intestine and brain. A phenome-wide association study and Mendelian randomization identified enrichment of microbiome trait loci in the metabolic, nutrition and environment domains and suggested the microbiome might have causal effects in ulcerative colitis and rheumatoid arthritis

    On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

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    A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

    Associations of autozygosity with a broad range of human phenotypes

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    In many species, the offspring of related parents suffer reduced reproductive success, a phenomenon known as inbreeding depression. In humans, the importance of this effect has remained unclear, partly because reproduction between close relatives is both rare and frequently associated with confounding social factors. Here, using genomic inbreeding coefficients (F-ROH) for >1.4 million individuals, we show that F-ROH is significantly associated (p <0.0005) with apparently deleterious changes in 32 out of 100 traits analysed. These changes are associated with runs of homozygosity (ROH), but not with common variant homozygosity, suggesting that genetic variants associated with inbreeding depression are predominantly rare. The effect on fertility is striking: F-ROH equivalent to the offspring of first cousins is associated with a 55% decrease [95% CI 44-66%] in the odds of having children. Finally, the effects of F-ROH are confirmed within full-sibling pairs, where the variation in F-ROH is independent of all environmental confounding.Peer reviewe

    Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

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    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR
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