1,648 research outputs found

    Nanocrystalline Zr3Al Made through Amorphization by Repeated Cold Rolling and Followed by Crystallization

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    The intermetallic compound Zr3Al is severely deformed by the method of repeated cold rolling. By X-ray diffraction it is shown that this leads to amorphization. TEM investigations reveal that a homogeneously distributed debris of very small nanocrystals is present in the amorphous matrix that is not resolved by X-ray diffraction. After heating to 773 K, the crystallization of the amorphous structure leads to a fully nanocrystalline structure of small grains (10 - 20 nm in diameter) of the non-equilibrium Zr2Al phase. It is concluded that the debris retained in the amorphous phase acts as nuclei. After heating to 973 K the grains grow to about 100 nm in diameter and the compound Zr3Al starts to form, that is corresponding to the alloy composition

    Montera: A Framework for Efficient Execution of Monte Carlo Codes on Grid Infrastructures

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    he objective of this work is to improve the performance of Monte Carlo codes on Grid production infrastructures. To do so, the codes and the grid sites are characterized with simple parameters to model their behaviors. Then, a new performance model for grid infrastructures is proposed, and an algorithm that employs this information is described. This algorithm dynamically calculates the number and size of tasks to execute on each site to maximize the performance and reduce makespan. Finally, a newly developed framework called Montera is presented. Montera deals with the execution of Monte Carlo codes in an unattended way, isolating the complexity of the problem from the final user. By employing two fusion Monte Carlo codes as example cases, along with the described characterizations and scheduling algorithm, a performance improvement up to 650 % over current best results is obtained on a real production infrastructure, together with enhanced stability and robustness

    Patiromer versus placebo to enable spironolactone use in patients with resistant hypertension and chronic kidney disease (AMBER): a phase 2, randomised, double-blind, placebo-controlled trial

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    BACKGROUND: Spironolactone is effective at reducing blood pressure in patients with uncontrolled resistant hypertension. However, the use of spironolactone in patients with chronic kidney disease can be restricted by hyperkalaemia. We evaluated use of the potassium binder patiromer to allow more persistent use of spironolactone in patients with chronic kidney disease and resistant hypertension. METHODS: In this phase 2 multicentre, randomised, double-blind, placebo-controlled study, we enrolled participants aged 18 years and older with chronic kidney disease (estimated glomerular filtration rate 25 to ≤45 mL/min per 1·73 m2) and uncontrolled resistant hypertension from 62 outpatient centres in ten countries (Bulgaria, Croatia, Georgia, Hungary, Ukraine, France, Germany, South Africa, the UK, and the USA). Patients meeting all eligibility criteria at the final screening visit were stratified by local serum potassium measurement (4·3 to <4·7 mmol/L vs 4·7 to 5·1 mmol/L) and history of diabetes. Participants were randomly assigned (1:1) with an interactive web response system to receive either placebo or patiromer (8·4 g once daily), in addition to open-label spironolactone (starting at 25 mg once daily) and their baseline blood pressure medications. Participants, the study team that administered treatments and measured blood pressure, and the investigators were masked to assigned treatment groups. Dose titrations were permitted after 1 week (patiromer) and 3 weeks (spironolactone). The primary endpoint was the between-group difference at week 12 in the proportion of patients on spironolactone. Efficacy endpoints and safety were assessed in all randomised patients (intention to treat). The study was registered with Clinicaltrials.gov, NCT03071263. FINDINGS: Between Feb 13, 2017, and Aug 20, 2018, we screened 574 patients. 295 (51%) of 574 patients met all inclusion criteria and were randomly assigned to spironolactone in addition to double-blind treatment with either placebo (n=148) or patiromer (n=147). At week 12, 98 (66%) of 148 patients in the placebo group and 126 (86%) of 147 patients in the patiromer group remained on spironolactone (between-group difference 19·5%, 95% CI 10·0-29·0; p<0·0001). Adverse events were mostly mild or moderate in severity and occurred in 79 (53%) of 148 patients in the placebo group and 82 (56%) of 147 patients in the patiromer group. INTERPRETATION: In patients with resistant hypertension and chronic kidney disease, patiromer enabled more patients to continue treatment with spironolactone with less hyperkalaemia. Persistent spironolactone enablement in this population of patients has clinical relevance for the treatment of resistant hypertension. FUNDING: Relypsa, a Vifor Pharma Group Company

    Direct visualization reveals dynamics of a transient intermediate during protein assembly

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    Interactions between proteins underlie numerous biological functions. Theoretical work suggests that protein interactions initiate with formation of transient intermediates that subsequently relax to specific, stable complexes. However, the nature and roles of these transient intermediates have remained elusive. Here, we characterized the global structure, dynamics, and stability of a transient, on-pathway intermediate during complex assembly between the Signal Recognition Particle (SRP) and its receptor. We show that this intermediate has overlapping but distinct interaction interfaces from that of the final complex, and it is stabilized by long-range electrostatic interactions. A wide distribution of conformations is explored by the intermediate; this distribution becomes more restricted in the final complex and is further regulated by the cargo of SRP. These results suggest a funnel-shaped energy landscape for protein interactions, and they provide a framework for understanding the role of transient intermediates in protein assembly and biological regulation

    Invariant Distribution of Promoter Activities in Escherichia coli

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    Cells need to allocate their limited resources to express a wide range of genes. To understand how Escherichia coli partitions its transcriptional resources between its different promoters, we employ a robotic assay using a comprehensive reporter strain library for E. coli to measure promoter activity on a genomic scale at high-temporal resolution and accuracy. This allows continuous tracking of promoter activity as cells change their growth rate from exponential to stationary phase in different media. We find a heavy-tailed distribution of promoter activities, with promoter activities spanning several orders of magnitude. While the shape of the distribution is almost completely independent of the growth conditions, the identity of the promoters expressed at different levels does depend on them. Translation machinery genes, however, keep the same relative expression levels in the distribution across conditions, and their fractional promoter activity tracks growth rate tightly. We present a simple optimization model for resource allocation which suggests that the observed invariant distributions might maximize growth rate. These invariant features of the distribution of promoter activities may suggest design constraints that shape the allocation of transcriptional resources

    Structural and Thermal Performance Assessment of Shipping Container as Post-Disaster Housing in Tropical Climates

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    Shipping Containers (SC) are a viable option as temporary or permanent housing for disaster victims due to their modularity, strength, and availability in large quantities around the world. While SCs as alternative housing has been extensively explored, few studies have focused on the structural and thermal performance of SCs in a tropical monsoon climate. This paper aims to contribute to a better knowledge of SC building construction by (1) investigating the SCs structural performance when subjected to a variety of loads, including gravity, earthquake, and very strong typhoon, and (2) assessing the thermal performance in a hot and humid climate. The case of Leyte, Philippines, a hot, humid, and typhoon-frequented region, is considered in this study. To meet the objectives, two SCs were combined to build a single-family house. First, the structural strength of the SCs, including the effect of cuts and openings, were investigated using finite element analysis. Second, the thermal condition of the SC was compared using four models with different insulation materials: no insulation, PE foam insulation (R-12), slightly higher insulation (R-13 fiberglass batt), and very high insulation (R-49 fiberglass batt) through building energy simulation. The paper concludes that SCs have inherently high strength and can withstand strong wind and earthquake. Stresses due to cuts and openings were minimized when the cuts/openings were placed far from the corner posts. On the other hand, increasing insulation R-value did not improve the indoor thermal condition of the SCs. More work needs to be done on making SCs thermally comfortable in hot and humid climates. Doi: 10.28991/cej-2021-03091735 Full Text: PD

    Feasibility of an Audit and Feedback Intervention to Facilitate Journal Policy Change Towards Greater Promotion of Transparency and Openness in Sports Science Research

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    Objectives: To evaluate (1) the feasibility of an audit-feedback intervention to facilitate sports science journal policy change, (2) the reliability of the Transparency of Research Underpinning Social Intervention Tiers (TRUST) policy evaluation form, and (3) the extent to which policies of sports science journals support transparent and open research practices. Methods: We conducted a cross-sectional, audit-feedback, feasibility study of transparency and openness standards of the top 38 sports science journals by impact factor. The TRUST form was used to evaluate journal policies support for transparent and open research practices. Feedback was provided to journal editors in the format of a tailored letter. Inter-rater reliability and agreement of the TRUST form was assessed using intraclass correlation coefficients and the standard error of measurement, respectively. Time-based criteria, fidelity of intervention delivery and qualitative feedback were used to determine feasibility. Results: The audit-feedback intervention was feasible based on the time taken to rate journals and provide tailored feedback. The mean (SD) score on the TRUST form (range 0–27) was 2.05 (1.99), reflecting low engagement with transparent and open practices. Inter-rater reliability of the overall score of the TRUST form was moderate [ICC (2,1) = 0.68 (95% CI 0.55–0.79)], with standard error of measurement of 1.17. However, some individual items had poor reliability. Conclusion: Policies of the top 38 sports science journals have potential for improved support for transparent and open research practices. The feasible audit-feedback intervention developed here warrants large-scale evaluation as a means to facilitate change in journal policies. Registration: OSF (https://osf.io/d2t4s/)

    Altruism can proliferate through group/kin selection despite high random gene flow

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    The ways in which natural selection can allow the proliferation of cooperative behavior have long been seen as a central problem in evolutionary biology. Most of the literature has focused on interactions between pairs of individuals and on linear public goods games. This emphasis led to the conclusion that even modest levels of migration would pose a serious problem to the spread of altruism in group structured populations. Here we challenge this conclusion, by analyzing evolution in a framework which allows for complex group interactions and random migration among groups. We conclude that contingent forms of strong altruism can spread when rare under realistic group sizes and levels of migration. Our analysis combines group-centric and gene-centric perspectives, allows for arbitrary strength of selection, and leads to extensions of Hamilton's rule for the spread of altruistic alleles, applicable under broad conditions.Comment: 5 pages, 2 figures. Supplementary material with 50 pages and 26 figure
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