454 research outputs found

    On the binding of nanometric hydrogen–helium clusters in tungsten

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    In this work we developed an embedded atom method potential for large scale atomistic simulations in the ternary tungsten–hydrogen–helium (W–H–He) system, focusing on applications in the fusion research domain. Following available ab initio data, the potential reproduces key interactions between H, He and point defects in W and utilizes the most recent potential for matrix W. The potential is applied to assess the thermal stability of various H–He complexes of sizes too large for ab initio techniques. The results show that the dissociation of H–He clusters stabilized by vacancies will occur primarily by emission of hydrogen atoms and then by break-up of V–He complexes, indicating that H–He interaction does influence the release of hydroge

    Proarrhythmic Remodeling of Calcium Homeostasis in Cardiac Disease; Implications for Diabetes and Obesity

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    A rapid growth in the incidence of diabetes and obesity has transpired to a major heath issue and economic burden in the postindustrial world, with more than 29 million patients affected in the United States alone. Cardiovascular defects have been established as the leading cause of mortality and morbidity of diabetic patients. Over the last decade, significant progress has been made in delineating mechanisms responsible for the diminished cardiac contractile function and enhanced propensity for malignant cardiac arrhythmias characteristic of diabetic disease. Rhythmic cardiac contractility relies upon the precise interplay between several cellular Ca2+ transport protein complexes including plasmalemmal L-type Ca2+ channels (LTCC), Na+-Ca2+ exchanger (NCX1), Sarco/endoplasmic Reticulum (SR) Ca2+-ATPase (SERCa2a) and ryanodine receptors (RyR2s), the SR Ca2+ release channels. Here we provide an overview of changes in Ca2+ homeostasis in diabetic ventricular myocytes and discuss the therapeutic potential of targeting Ca2+ handling proteins in the prevention of diabetes-associated cardiomyopathy and arrhythmogenesis

    MicroRNAs in cardiovascular disease

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    Rapid and accurate diagnosis of heart attacks—and the assessment of damage—are critical for improving coronary care. Mature microRNAs (miRNAs) are abundant, easily measured, and relatively stable in blood plasma. If they prove indicative of disease states, miRNAs measured from peripheral blood may be a particularly attractive source for routine clinical assessments

    Effect of neutron irradiation to 0.7 and 1.4 dpa on the tensile mechanical properties and microstructure of EUROFER97 steel

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    Several grades of reduced-activation ferritic-martensitic (RAFM) steels have been proposed for fusion applications (e.g., blanket first wall) since the 1990s all over the world. Four batches of the European reference RAFM steel EUROFER97 have been produced since 1998. The RCC-MRx design code, developed, among others, for fusion reactors, currently contains a provisional section dedicated to EUROFER97, encompassing properties of the first two batches, whereas minimum three batches are required for a full qualification and final inclusion of a material into RCC-MRx. The EUROfusion project coordinates efforts to broaden the knowledge of EUROFER97 properties relevant for fusion reactors ITER and DEMO, preparing them for closing the database gaps in RCC-MRx and aggregating them in the DEMO material property handbook (MPH). Its purpose is to provide average and minimum curves of required properties according to the DEMO engineering design and manufacturing needs. The present work reports mechanical properties and fractographic analysis of batch 4 of neutron-irradiated EUROFER97 for the first time. The measured strength and ductility are in line with the data already aggregated in the MPH. SEM investigation confirms that the dimple fracture is retained in the material after neutron irradiation up to 1.4 dpa in the temperature range 25…550 °C
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