65 research outputs found

    Grain Boundary Segregation Predicted by Quantum-Accurate Segregation Spectra but not by Classical Models

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    In alloys, solute segregation at grain boundaries is classically attributed to three driving forces: a high solution enthalpy, a high size mismatch, and a high difference in interfacial energy. These effects are generally cast into a single scalar segregation energy and used to predict grain boundary solute enrichment or depletion. This approach neglects the physics of segregation at many competing grain boundary sites, and can also miss electronic effects that are energetically significant to the problem. In this paper, we demonstrate that such driving forces cannot explain, nor thus predict, segregation in some alloys. Using quantum-accurate segregation spectra that have recently become available for some polycrystalline alloys, we predict strong segregation for gold in aluminum, a solvent-solute combination that does not conform to classical driving forces. Our experiments confirm these predictions and reveal gold enrichment at grain boundaries that is two orders of magnitude over the bulk lattice solute concentration

    MnO2-coated Ni nanorods: Enhanced high rate behavior in pseudo-capacitive supercapacitor

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    Ni nanorods prepared by electrochemical growth through an anodized aluminium oxide membrane were used as substrate for the electrodeposition of MnO2 either in potentiostatic mode or by a pulsed method. Electrochemical deposition parameters were chosen for an homogeneous deposit onto Ni nanorods. Resulting Ni supportedMnO2 electrodes were tested for electrochemical performances as nanostructured negative electrodes for supercapacitors. They exhibited initial capacitances up to 190 F/g and remarkable performances at high charge/discharge rates

    Accelerated surgery versus standard care in hip fracture (HIP ATTACK): an international, randomised, controlled trial

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    Design and baseline characteristics of the finerenone in reducing cardiovascular mortality and morbidity in diabetic kidney disease trial

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    Background: Among people with diabetes, those with kidney disease have exceptionally high rates of cardiovascular (CV) morbidity and mortality and progression of their underlying kidney disease. Finerenone is a novel, nonsteroidal, selective mineralocorticoid receptor antagonist that has shown to reduce albuminuria in type 2 diabetes (T2D) patients with chronic kidney disease (CKD) while revealing only a low risk of hyperkalemia. However, the effect of finerenone on CV and renal outcomes has not yet been investigated in long-term trials. Patients and Methods: The Finerenone in Reducing CV Mortality and Morbidity in Diabetic Kidney Disease (FIGARO-DKD) trial aims to assess the efficacy and safety of finerenone compared to placebo at reducing clinically important CV and renal outcomes in T2D patients with CKD. FIGARO-DKD is a randomized, double-blind, placebo-controlled, parallel-group, event-driven trial running in 47 countries with an expected duration of approximately 6 years. FIGARO-DKD randomized 7,437 patients with an estimated glomerular filtration rate >= 25 mL/min/1.73 m(2) and albuminuria (urinary albumin-to-creatinine ratio >= 30 to <= 5,000 mg/g). The study has at least 90% power to detect a 20% reduction in the risk of the primary outcome (overall two-sided significance level alpha = 0.05), the composite of time to first occurrence of CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for heart failure. Conclusions: FIGARO-DKD will determine whether an optimally treated cohort of T2D patients with CKD at high risk of CV and renal events will experience cardiorenal benefits with the addition of finerenone to their treatment regimen. Trial Registration: EudraCT number: 2015-000950-39; ClinicalTrials.gov identifier: NCT02545049

    Large expert-curated database for benchmarking document similarity detection in biomedical literature search

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    Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

    Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

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    Background: Understanding the health consequences associated with exposure to risk factors is necessary to inform public health policy and practice. To systematically quantify the contributions of risk factor exposures to specific health outcomes, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 aims to provide comprehensive estimates of exposure levels, relative health risks, and attributable burden of disease for 88 risk factors in 204 countries and territories and 811 subnational locations, from 1990 to 2021. Methods: The GBD 2021 risk factor analysis used data from 54 561 total distinct sources to produce epidemiological estimates for 88 risk factors and their associated health outcomes for a total of 631 risk–outcome pairs. Pairs were included on the basis of data-driven determination of a risk–outcome association. Age-sex-location-year-specific estimates were generated at global, regional, and national levels. Our approach followed the comparative risk assessment framework predicated on a causal web of hierarchically organised, potentially combinative, modifiable risks. Relative risks (RRs) of a given outcome occurring as a function of risk factor exposure were estimated separately for each risk–outcome pair, and summary exposure values (SEVs), representing risk-weighted exposure prevalence, and theoretical minimum risk exposure levels (TMRELs) were estimated for each risk factor. These estimates were used to calculate the population attributable fraction (PAF; ie, the proportional change in health risk that would occur if exposure to a risk factor were reduced to the TMREL). The product of PAFs and disease burden associated with a given outcome, measured in disability-adjusted life-years (DALYs), yielded measures of attributable burden (ie, the proportion of total disease burden attributable to a particular risk factor or combination of risk factors). Adjustments for mediation were applied to account for relationships involving risk factors that act indirectly on outcomes via intermediate risks. Attributable burden estimates were stratified by Socio-demographic Index (SDI) quintile and presented as counts, age-standardised rates, and rankings. To complement estimates of RR and attributable burden, newly developed burden of proof risk function (BPRF) methods were applied to yield supplementary, conservative interpretations of risk–outcome associations based on the consistency of underlying evidence, accounting for unexplained heterogeneity between input data from different studies. Estimates reported represent the mean value across 500 draws from the estimate's distribution, with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values across the draws. Findings: Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021, contributing 8·0% (95% UI 6·7–9·4) of total DALYs, followed by high systolic blood pressure (SBP; 7·8% [6·4–9·2]), smoking (5·7% [4·7–6·8]), low birthweight and short gestation (5·6% [4·8–6·3]), and high fasting plasma glucose (FPG; 5·4% [4·8–6·0]). For younger demographics (ie, those aged 0–4 years and 5–14 years), risks such as low birthweight and short gestation and unsafe water, sanitation, and handwashing (WaSH) were among the leading risk factors, while for older age groups, metabolic risks such as high SBP, high body-mass index (BMI), high FPG, and high LDL cholesterol had a greater impact. From 2000 to 2021, there was an observable shift in global health challenges, marked by a decline in the number of all-age DALYs broadly attributable to behavioural risks (decrease of 20·7% [13·9–27·7]) and environmental and occupational risks (decrease of 22·0% [15·5–28·8]), coupled with a 49·4% (42·3–56·9) increase in DALYs attributable to metabolic risks, all reflecting ageing populations and changing lifestyles on a global scale. Age-standardised global DALY rates attributable to high BMI and high FPG rose considerably (15·7% [9·9–21·7] for high BMI and 7·9% [3·3–12·9] for high FPG) over this period, with exposure to these risks increasing annually at rates of 1·8% (1·6–1·9) for high BMI and 1·3% (1·1–1·5) for high FPG. By contrast, the global risk-attributable burden and exposure to many other risk factors declined, notably for risks such as child growth failure and unsafe water source, with age-standardised attributable DALYs decreasing by 71·5% (64·4–78·8) for child growth failure and 66·3% (60·2–72·0) for unsafe water source. We separated risk factors into three groups according to trajectory over time: those with a decreasing attributable burden, due largely to declining risk exposure (eg, diet high in trans-fat and household air pollution) but also to proportionally smaller child and youth populations (eg, child and maternal malnutrition); those for which the burden increased moderately in spite of declining risk exposure, due largely to population ageing (eg, smoking); and those for which the burden increased considerably due to both increasing risk exposure and population ageing (eg, ambient particulate matter air pollution, high BMI, high FPG, and high SBP). Interpretation: Substantial progress has been made in reducing the global disease burden attributable to a range of risk factors, particularly those related to maternal and child health, WaSH, and household air pollution. Maintaining efforts to minimise the impact of these risk factors, especially in low SDI locations, is necessary to sustain progress. Successes in moderating the smoking-related burden by reducing risk exposure highlight the need to advance policies that reduce exposure to other leading risk factors such as ambient particulate matter air pollution and high SBP. Troubling increases in high FPG, high BMI, and other risk factors related to obesity and metabolic syndrome indicate an urgent need to identify and implement interventions

    Matériaux composites électroactifs à porosité contrôlée

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    Parmi les systèmes de stockage de l'énergie électrique, les dispositifs électrochimiques sont intéressants car ils convertissent l'énergie chimique en énergie électrique. Nous pouvons citer les supercondensateurs et les batteries Li-ion qui possèdent une densité de puissance élevée et une bonne densité d'énergie, respectivement. Ce travail de thèse a été axé sur la préparation de matériaux composites d'électrode MnO2/C pour supercondensateur, SnO2/C pour batterie Li-ion et la synthèse de SiC poreux. A partir d'un carbone mésoporeux (900m2/g) synthétisé par voie template, le dépôt de matériau actif est réalisé par (co-)précipitation. En ce concerne le composite MnO2/C, les performances électrochimiques suivent deux comportements distincts selon la teneur en MnO2 dans le matériau. Un optimum dans la teneur a été observé pour l'obtention d'un maximum de capacité (900F/g). Pour les batteries Li-ion, le carbone contient l'expansion volumique induite par la lithiation de SnO2 dans le cas matériau composite SnO2/C. Cependant, l'électrode de SnO2 pur n'a pas donné les résultats escomptés. La synthèse de SiC poreux a procède par la réduction d'un composite SiO2/C par magnésiothermie à 800C pendant 24h. Le matériau obtenu est une réplique inverse de la structure de la siliceAmong all systems for electrical storage, electrochemical devices are interesting because they turn chemical energy into electrical energy. Supercapacitor and Li-ion battery have high power density and good energy density, respectively. The topic of the present work is the preparation of composite electrode material MnO2/C for supercapacitor, SnO2/C for Li-ion battery and synthesis of porous SiC. This could be achieved starting by the synthesis of mesoporous carbon (900m2/g) following a hard template method. At first, the evaluation of electrochemical performances of composite electrode material for supercapacitor shows two different behaviours versus the ratio of MnO2. We could observe an optimal ratio for which capacitance was maximal (900F/g). Secondly, the volumic variations occurring while charge/discharge of SnO2/C electrode materials are contained by the carbon matrix. In spite of limited electrochemical performances for pure SnO2 electrode material, the cyclability of SnO2/C electrode materials is enhanced. At last, the synthesis of porous SiC can be achieved by the thermal reduction of SiO2/C composite using Mg as reducing agent. The as-prepared material is a replica of silica templateMONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

    A discrete element contact model for fatigue crack growth analysis

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    The proposed contact model offers a reliable technique for realizing continual crack growth in discrete samples. Such contact model could combine with Paris’ law, thus further enhancing its capacity of simulating fatigue crack growth. Based on the proposed contact model, calculation of stress intensity factor (SIF) only requires contact force and relative displacement of consisting particles, and its convenience indicates a promising generalizability in fatigue crack growth analysis for geomaterials

    Mesoporous carbon – Manganese Oxide composite as negative electrode material for supercapacitors

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    International audience3D-assembles of silica spheres were used as hard template to synthesize porous carbon materials with large mesopores to be included as current collectors in supercapacitors and developing large surface areas reaching up to 900m2.g-1. Birnessite-type MnO2 was deposited by a co-precipitation method in the porous network. Electrochemical performances of resulting MnO2/C nanocomposites were evaluated by cyclic voltammetry and showed an initial capacitance and a retained capacitance after 500 cycles for the nanocomposite at 6wt% MnO2 in C of about 660 and 490 F.g-1, respectively
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