39 research outputs found

    Longitudinal analysis of risk factors associated with severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection among hemodialysis patients and healthcare personnel in outpatient hemodialysis centers

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    In this prospective, longitudinal study, we examined the risk factors for severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection among a cohort of chronic hemodialysis (HD) patients and healthcare personnel (HCPs) over a 6-month period. The risk of SARS-CoV-2 infection among HD patients and HCPs was consistently associated with a household member having SARS-CoV-2 infection

    Cationic exchange in nanosized ZnFe₂O₄ spinel revealed by experimental and simulated near-edge absorption structure

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    The nonequilibrium cation site occupancy in nanosized zinc ferrites ( ∼ 6 – 13 nm ) with different degree of inversion ( ∼ 0.2 to 0.4) was investigated using Fe and Zn K -edge x-ray absorption near edge spectroscopy (XANES) and extended x-ray absorption fine structure, and magnetic measurements. The very good agreement between experimental and ab initio calculations on the Zn K -edge XANES region clearly shows the large Zn²⁺ ( A ) → Zn²⁺ [ B ] transference that takes place in addition to the well-identified Fe³⁺ [ B ] → Fe³⁺ ( A ) one, without altering the long-range structural order. XANES spectra features as a function of the spinel inversion were shown to depend on the configuration of the ligand shells surrounding the absorbing atom. This XANES approach provides a direct way to sense cationic inversion in these Zn-containing spinel ferrites. We also demonstrated that a mechanical crystallization takes place on nanocrystalline spinel that causes an increase of both grain and magnetic sizes and, simultaneously, generates a significant augment of the inversion.Instituto de Física La Plat

    Pest population dynamics are related to a continental overwintering gradient

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    Overwintering success is an important determinant of arthropod populations that must be considered as climate change continues to influence the spatiotemporal population dynamics of agricultural pests. Using a long-term monitoring database and biologically relevant overwintering zones, we modeled the annual and seasonal population dynamics of a common pest, Helicoverpa zea (Boddie), based on three overwintering suitability zones throughout North America using four decades of soil temperatures: the southern range (able to persist through winter), transitional zone (uncertain overwintering survivorship), and northern limits (unable to survive winter). Our model indicates H. zea population dynamics are hierarchically structured with continental-level effects that are partitioned into three geographic zones. Seasonal populations were initially detected in the southern range, where they experienced multiple large population peaks. All three zones experienced a final peak between late July (southern range) and mid-August to mid-September (transitional zone and northern limits). The southern range expanded by 3% since 1981 and is projected to increase by twofold by 2099 but the areas of other zones are expected to decrease in the future. These changes suggest larger populations may persist at higher latitudes in the future due to reduced low-temperature lethal events during winter. Because H. zea is a highly migratory pest, predicting when populations accumulate in one region can inform synchronous or lagged population development in other regions. We show the value of combining long-term datasets, remotely sensed data, and laboratory findings to inform forecasting of insect pests

    CSR and related terms in SME owner-managers' mental models in six European countries: national context matters

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    As a contribution to the emerging field of corporate social responsibility (CSR) cognition, this article reports on the findings of an exploratory study that compares SME owner–managers’ mental models with regard to CSR and related concepts across six European countries (Belgium, Italy, Norway, France, UK, Spain). Utilising Repertory Grid Technique, we found that the SME owner–managers’ mental models show a few commonalities as well as a number of differences across the different country samples. We interpret those differences by linking individual cognition to macro-environmental variables, such as language, national traditions and dissemination mechanisms. The results of our exploratory study show that nationality matters but that classifications of countries as found in the comparative capitalism literature do not exactly mirror national differences in CSR cognition and that these classifications need further differentiation. The findings from our study raise questions on the universality of cognition of academic management concepts and warn that promotion of responsible business practice should not rely on the use of unmediated US American management terminology

    IL28B, HLA-C, and KIR Variants Additively Predict Response to Therapy in Chronic Hepatitis C Virus Infection in a European Cohort: A Cross-Sectional Study

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    Vijayaprakash Suppiah and colleagues show that genotyping hepatitis C patients for the IL28B, HLA-C, and KIR genes improves the ability to predict whether or not patients will respond to antiviral treatment

    Interaction Pattern of Arg 62 in the A-Pocket of Differentially Disease-Associated HLA-B27 Subtypes Suggests Distinct TCR Binding Modes

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    The single amino acid replacement Asp116His distinguishes the two subtypes HLA-B*2705 and HLA-B*2709 which are, respectively, associated and non-associated with Ankylosing Spondylitis, an autoimmune chronic inflammatory disease. The reason for this differential association is so far poorly understood and might be related to subtype-specific HLA:peptide conformations as well as to subtype/peptide-dependent dynamical properties on the nanoscale. Here, we combine functional experiments with extensive molecular dynamics simulations to investigate the molecular dynamics and function of the conserved Arg62 of the α1-helix for both B27 subtypes in complex with the self-peptides pVIPR (RRKWRRWHL) and TIS (RRLPIFSRL), and the viral peptides pLMP2 (RRRWRRLTV) and NPflu (SRYWAIRTR). Simulations of HLA:peptide systems suggest that peptide-stabilizing interactions of the Arg62 residue observed in crystal structures are metastable for both B27 subtypes under physiological conditions, rendering this arginine solvent-exposed and, probably, a key residue for TCR interaction more than peptide-binding. This view is supported by functional experiments with conservative (R62K) and non-conservative (R62A) B*2705 and B*2709 mutants that showed an overall reduction in their capability to present peptides to CD8+ T cells. Moreover, major subtype-dependent differences in the peptide recognition suggest distinct TCR binding modes for the B*2705 versus the B*2709 subtype

    GWAS meta-analysis of over 29,000 people with epilepsy identifies 26 risk loci and subtype-specific genetic architecture

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    Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants explain between 39.6% and 90% of genetic risk for GGE and its subtypes. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analyses of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current antiseizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment

    Genome-wide identification and phenotypic characterization of seizure-associated copy number variations in 741,075 individuals

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    Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 individuals with seizure disorders, 16,109 individuals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 individuals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of individuals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between individual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice

    Access Denied? The Unintended Consequences of Pending Drug Pricing Rules

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    The government of Canada now plans to bring into force new federal drug pricing regulations on 1 July 2022. We do not take issue with the goal of medication affordability, which is vital in healthcare the world over. Our concern is that the new guidelines are being implemented without due consideration for three major unintended consequences: regulatory changes will lower the number of clinical trials for new medications in Canada, fewer clinical trials will mean lower research and development investments, and changes will reduce patients’ access to new medications. Access to effective medications is a cornerstone of healthcare for Canadian patients. As physicians, our duty to patient care demands that we tell the government to protect the right of Canadians to timely access to life-changing medicines

    Thermal Evolution of Pt-Rich FePt/Fe₃O₄ Heterodimers Studied Using X-ray Absorption Near-Edge Spectroscopy

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    FePt/Fe₃O₄ nanoparticles can be used as building blocks to obtain, upon thermal annealing, magnetic nanocomposites with combined magnetic properties. Although the pre- and postannealed samples are usually well-characterized, a detailed investigation during annealing is necessary to reveal the role of intermediate processes to produce a desirable composite. We present an alternative method using in situ XANES to investigate the thermal evolution of oleic acid- and oleylamine-coated Pt-rich FePt/Fe₃O₄ heterodimers. As the temperature increases, a progressive reduction of Fe₃O₄ to FeO occurs helped by the thermolysis of the surfactants, while above 550 K Fe₃Pt starts to be formed. At 840 K an abrupt increase of FeO further drives the phase transformation to stabilize the iron platinum soft phase. Thus, the Fe₃O₄ reduction acts as catalyst that promotes the Fe and Pt interdiffusion between the Pt-rich FePt and Fe₃O₄/FeO to form Fe₃Pt instead of exchange-coupled FePt/Fe₃O₄ with hard magnetic properties. In addition, the role of the interface of the heterodimer ends is discussed. The pre- and postannealed samples were also characterized by TEM, XRD, EXAFS, magnetometry, and Mössbauer spectroscopy.Instituto de Física La Plat
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