427 research outputs found
CFD Validation of Forced and Natural Convection for the Open Phase of IAEA Benchmark CRP-I31038
The goal of the IAEA Coordinated Research Project “Benchmark of Transition from Forced to Natural Circulation Experiment with Heavy Liquid Metal Loop” (CRP—I31038) is to develop Member State advanced fast reactor analytical capabilities for simulation and design using system, CFD, and subchannel analysis codes. Here, CFD validation employing the commercial CFD code Star CCM + applied to the fuel pin simulator for forced and natural convection cases in the open phase is presented. Experimental data are provided in the benchmark specification provided by ENEA (Italian National Agency for New Technologies, Energy and Sustainable Economic Development) for the NACIE-UP facility (NAtural CIrculation Experiment-UPgrade). Considered is the fuel pin simulator with 19 pins, each consisting of a preheated lower section and heated upper sections, respectively. Three configurations: (i) all pins heated, (ii) inner 7 pins heated and (iii) asymmetric heating, are studied. For each heating configuration data for forced and natural convection are provided. Here, case (i) is studied. Temperatures at three planes are measured near the inlet, in the middle and near the end of the heated section, respectively. In addition, the axial temperature along the wall of one fuel pin simulator (in second row) is measured so that in total 67 thermocouples measure fluid and wall temperatures for validation purposes. The validation confirms that the thermohydraulic inside the fuel pin simulator can be simulated with a good accuracy. Applied is a polyhedral mesh with 2 prism layers, the k-omega SST model with all all-wall treatment and order unity y + values. Moreover, a grid-sensitivity, the importance of conjugate heat transfer inside the fuel pin simulators and the wrapper are studied. The studies indicate that it is possible to implement further simplifications without corrupting the accuracy of the simulation to reduce computational effort
Self-assembly of binary nanoparticle dispersions: from square arrays and stripe phases to colloidal corrals
The generation of nanoscale square and stripe patterns is of major
technological importance since they are compatible with industry-standard
electronic circuitry. Recently, a blend of diblock copolymer interacting via
hydrogen-bonding was shown to self-assemble in square arrays. Motivated by
those experiments we study, using Monte Carlo simulations, the pattern
formation in a two-dimensional binary mixture of colloidal particles
interacting via isotropic core-corona potentials. We find a rich variety of
patterns that can be grouped mainly in aggregates that self-assemble in regular
square lattices or in alternate strips. Other morphologies observed include
colloidal corrals that are potentially useful as surface templating agents.
This work shows the unexpected versatility of this simple model to produce a
variety of patterns with high technological potential.Comment: 13 pages, 5 figures, submitte
Rapid Evolutionary Rates and Unique Genomic Signatures Discovered in the First Reference Genome for the Southern Ocean Salp, Salpa thompsoni (Urochordata, Thaliacea)
A preliminary genome sequence has been assembled for the Southern Ocean salp, Salpa thompsoni (Urochordata, Thaliacea). Despite the ecological importance of this species in Antarctic pelagic food webs and its potential role as an indicator of changing Southern Ocean ecosystems in response to climate change, no genomic resources are available for S. thompsoni or any closely related urochordate species. Using a multiple-platform, multiple-individual approach, we have produced a 318,767,936-bp genome sequence, covering \u3e50% of the estimated 602 Mb (±173 Mb) genome size for S. thompsoni. Using a nonredundant set of predicted proteins, \u3e50% (16,823) of sequences showed significant homology to known proteins and ∼38% (12,151) of the total protein predictions were associated with Gene Ontology functional information. We have generated 109,958 SNP variant and 9,782 indel predictions for this species, serving as a resource for future phylogenomic and population genetic studies. Comparing the salp genome to available assemblies for four other urochordates, Botryllus schlosseri, Ciona intestinalis, Ciona savignyi and Oikopleura dioica, we found that S. thompsoni shares the previously estimated rapid rates of evolution for these species. High mutation rates are thus independent of genome size, suggesting that rates of evolution \u3e1.5 times that observed for vertebrates are a broad taxonomic characteristic of urochordates. Tests for positive selection implemented in PAML revealed a small number of genes with sites undergoing rapid evolution, including genes involved in ribosome biogenesis and metabolic and immune process that may be reflective of both adaptation to polar, planktonic environments as well as the complex life history of the salps. Finally, we performed an initial survey of small RNAs, revealing the presence of known, conserved miRNAs, as well as novel miRNA genes; unique piRNAs; and mature miRNA signatures for varying developmental stages. Collectively, these resources provide a genomic foundation supporting S. thompsoni as a model species for further examination of the exceptional rates and patterns of genomic evolution shown by urochordates. Additionally, genomic data will allow for the development of molecular indicators of key life history events and processes and afford new understandings and predictions of impacts of climate change on this key species of Antarctic pelagic ecosystems
COI metabarcoding of zooplankton species diversity for time-series monitoring of the NW Atlantic continental shelf
© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bucklin, A., Batta-Lona, P., Questel, J., Wiebe, P., Richardson, D., Copley, N., & O’Brien, T. COI metabarcoding of zooplankton species diversity for time-series monitoring of the NW Atlantic continental shelf. Frontiers in Marine Science, 9, (2022): 867893, https://doi.org/10.3389/fmars.2022.867893.Marine zooplankton are rapid-responders and useful indicators of environmental variability and climate change impacts on pelagic ecosystems on time scales ranging from seasons to years to decades. The systematic complexity and taxonomic diversity of the zooplankton assemblage has presented significant challenges for routine morphological (microscopic) identification of species in samples collected during ecosystem monitoring and fisheries management surveys. Metabarcoding using the mitochondrial Cytochrome Oxidase I (COI) gene region has shown promise for detecting and identifying species of some – but not all – taxonomic groups in samples of marine zooplankton. This study examined species diversity of zooplankton on the Northwest Atlantic Continental Shelf using 27 samples collected in 2002-2012 from the Gulf of Maine, Georges Bank, and Mid-Atlantic Bight during Ecosystem Monitoring (EcoMon) Surveys by the NOAA NMFS Northeast Fisheries Science Center. COI metabarcodes were identified using the MetaZooGene Barcode Atlas and Database (https://metazoogene.org/MZGdb) specific to the North Atlantic Ocean. A total of 181 species across 23 taxonomic groups were detected, including a number of sibling and cryptic species that were not discriminated by morphological taxonomic analysis of EcoMon samples. In all, 67 species of 15 taxonomic groups had ≥ 50 COI sequences; 23 species had >1,000 COI sequences. Comparative analysis of molecular and morphological data showed significant correlations between COI sequence numbers and microscopic counts for 5 of 6 taxonomic groups and for 5 of 7 species with >1,000 COI sequences for which both types of data were available. Multivariate statistical analysis showed clustering of samples within each region based on both COI sequence numbers and EcoMon counts, although differences among the three regions were not statistically significant. The results demonstrate the power and potential of COI metabarcoding for identification of species of metazoan zooplankton in the context of ecosystem monitoring.This publication resulted in part from support provided by the Scientific Committee on Oceanic Research (SCOR). Funds were also contributed by the U.S. National Science Foundation (Grant OCE-1840868) and by national SCOR committees
Temporal Effects in a Security Inspection Task: Breakdown of Performance Components
Data from certified screeners performing an x-ray inspection task for 4 hours, or 1000 images, were analyzed to identify the nature of the vigilance decrement. The expected vigilance decrement was found, with performance measured by probability of detection (PoD) and probability of false alarm [P(FA)] decreasing from hour 1 to hour 4. Correlations between PoD and P(FA) indicate that sensitivity between hours remained the same, however a shift in criterion (Beta) occurred. Significant decreases in both detection and stopping time were found from the first hour to the second, third, and fourth hour. Evidence of changes in the search component of the time per item was found to account for part of the vigilance decrement. As the task continued, participants spent less time actively searching the image, as opposed to other activities. Evidence is provided for truncation of active search as security inspection continues
Seven days treatment with the angiotensin II type 2 receptor agonist C21 in hospitalized COVID-19 patients; a placebo-controlled randomised multi-centre double-blind phase 2 trial
Background:
COVID-19 morbidity and mortality remains high and the need for safe and effective drugs continues despite vaccines.
Methods:
Double-blind, placebo-controlled, multi-centre, randomised, parallel group phase 2 trial to evaluate safety and efficacy of oral angiotensin II type 2 receptor agonist C21 in hospitalized patients with COVID-19 and CRP ≥ 50-150 mg/L conducted at eight sites in India (NCT04452435). Patients were randomly assigned 100 mg C21 bid or placebo for 7 days in addition to standard of care. Primary endpoint: reduction in CRP. The study period was 21 July to 13 October 2020.
Findings:
106 patients were randomised and included in the analysis (51 C21, 55 placebo). There was no significant group difference in reduction of CRP, 81% and 78% in the C21 and placebo groups, respectively, with a treatment effect ratio of 0.85 [90% CI 0.57, 1.26]. In a secondary analysis in patients requiring supplemental oxygen at randomisation, CRP was reduced in the C21 group compared to placebo. At the end of the 7-day treatment, 37 (72.5%) and 30 (54.5%) of the patients did not require supplemental oxygen in the C21 and placebo group, respectively (OR 2.20 [90% CI 1.12, 4.41]). A post hoc analysis showed that at day 14, the proportion of patients not requiring supplemental oxygen was 98% and 80% in the C21 group compared to placebo (OR 12.5 [90% CI 2.9, 126]). Fewer patients required mechanical ventilation (one C21 patient; four placebo patients), and C21 was associated with a numerical reduction in the mortality rate (one vs three in the C21 and placebo group, respectively). Treatment with C21 was safe and well tolerated.
Interpretation:
Among hospitalised patients with COVID-19 receiving C21 for 7 days there was no reduction in CRP compared to placebo. However, a post-hoc analysis indicated a marked reduction of requirement for oxygen at day 14. The day 14 results from this study justify further evaluation in a Phase 3 study and such a trial is currently underway.
Funding:
Vicore Pharma AB and LifeArc, UK
Letter to the Editor: 1H and 15N sequential assignment and solution secondary structure of 15N labelled human pancreatic ribonuclease
Several members of the RNase A (bovine pancreatic ribonuclease) superfamily exhibit anticancer activity. Among the mammalian members of the superfamily, most of the antitumour activity studies have been carried out with a dimeric RNase from bovine seminal vesicles (BS-RNase) (Youle and D’Alessio, 1997). These studies show that dimer formation is crucial for cytotoxicity. Investigations are underway to transfer by protein engineering the structural determinants responsible for the antitumour activity of BS-RNase to a human immunocompatible backbone (Piccoli et al., 1999). Knowledge of the 3D structures of the involved proteins is central to rationally fulfil this objective. As a first step, human pancreatic ribonuclease (HPRNase), a 127-residue monomeric protein (Beintema et al., 1984) was constructed (Russo et al., 1993). The expressed recombinant protein was undistinguishable from the natural product isolated from human pancreas (Weickmann et al., 1981). Here, we present the assignment of practically all of its 1H and 15N spectral resonances, as well as its secondary structure in aqueous solution. The cytotoxic activity of ribonucleases has been related to their ability to evade the cytosolic ribonuclease inhibitor (RI) (Murthy and Sirdeshmukh, 1992). The structure of HP-RNase will be useful to introduce changes in it in order to increase its resistance to RI.This work was supported by the European Commission under the INCO-Copernicus Project No. IC15 CT 96-0903. The assistance of the Ministerio de Asuntos Exteriores (Spain) and OMFB (Hungary) (project E26/97) is gratefully acknowledged
Эпидемиологические исследования в сексологии
Представлены результаты эпидемиологического исследования, позволившие автору на примере обследования 1000 человек популяции из западного региона Украины сформулировать основные закономерности изменения отношения к браку и сексуального поведения мужчин и женщин в современном обществе.The findings of epidemiological study, which allowed the author to formulate main regularities of the changes in the attitude to the marriage and sexual behavior of men and women in the contemporary society on the example of the examination of 1000 persons from the western regions of Ukraine, are presented
Direct and indirect cardiovascular and cardiometabolic sequelae of the combined anti-retroviral therapy on people living with HIV
With reports of its emergence as far back as the early 1900s, human immunodeficiency virus (HIV) has become one of the deadliest and most difficult viruses to treat in the era of modern medicine. Although not always effective, HIV treatment has evolved and improved substantially over the past few decades. Despite the major advancements in the efficacy of HIV therapy, there are mounting concerns about the physiological, cardiovascular, and neurological sequelae of current treatments. The objective of this review is to (Blattner et al., Cancer Res., 1985, 45(9 Suppl), 4598s–601s) highlight the different forms of antiretroviral therapy, how they work, and any effects that they may have on the cardiovascular health of patients living with HIV, and to (Mann et al., J Infect Dis, 1992, 165(2), 245–50) explore the new, more common therapeutic combinations currently available and their effects on cardiovascular and neurological health. We executed a computer-based literature search using databases such as PubMed to look for relevant, original articles that were published after 1998 to current year. Articles that had relevance, in any capacity, to the field of HIV therapy and its intersection with cardiovascular and neurological health were included. Amongst currently used classes of HIV therapies, protease inhibitors (PIs) and combined anti-retroviral therapy (cART) were found to have an overall negative effect on the cardiovascular system related to increased cardiac apoptosis, reduced repair mechanisms, block hyperplasia/hypertrophy, decreased ATP production in the heart tissue, increased total cholesterol, low-density lipoproteins, triglycerides, and gross endothelial dysfunction. The review of Integrase Strand Transfer Inhibitors (INSTI), Nucleoside Reverse Transcriptase Inhibitors (NRTI), and Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTI) revealed mixed results, in which both positive and negative effects on cardiovascular health were observed. In parallel, studies suggest that autonomic dysfunction caused by these drugs is a frequent and significant occurrence that needs to be closely monitored in all HIV + patients. While still a relatively nascent field, more research on the cardiovascular and neurological implications of HIV therapy is crucial to accurately evaluate patient risk
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