45 research outputs found

    Space charge limited current mechanism in Bi2S3 nanowires

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    We report on the charge transport properties of individual Bi2S3 nanowires grown within the pores of anodized aluminum oxide templates. The mean pore diameter was 80 nm. Space charge limited current is the dominating conduction mechanism at temperatures below 160 K. Characteristic parameters of nanowires, such as trap concentration and trap characteristic energy, were estimated from current–voltage characteristics at several temperatures

    Behaviour of advanced tritium breeder pebbles under simultaneous action of accelerated electrons and high temperature

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    The authors greatly acknowledge the technical and experimen-tal support of O. Valtenbergs and L. Avotina (Institute of Chemical Physics, University of Latvia). The work is performed in the frames of the University of Latvia financed project No. Y9-B044-ZF-N-300, “Nano, Quantum Technologies, and Innovative Materials for Eco-nomics”.Advanced lithium orthosilicate (Li4SiO4) pebbles with additions of lithium metatitanate (Li2TiO3) as a secondary phase are suggested as a potential source for tritium breeding in future nuclear fusion reactors. The advanced Li4SiO4 pebbles with different contents of Li2TiO3 were examined before and after simultaneous action of 5 MeV accelerated electron beam (dose rate: up to 10 MGy h−1) and high temperature (up to 1120 K) in a dry argon atmosphere. The accumulated radiation-induced defects (RD) and radiolysis products (RP) were studied by electron spin resonance (ESR) spectrometry and thermally stimulated luminescence (TSL) technique. The phase transitions were studied with powder X-ray diffraction (p-XRD). The microstructure and mechanical strength of the pebbles, before and after irradiation, were investigated by scanning electron microscopy (SEM) and comprehensive crush load tests. The obtained results revealed that the irradiation temperature has a significant impact on the accumulation of RD and RP in the advanced Li4SiO4 pebbles, and with an increasing content of Li2TiO3, the concentration of accumulated paramagnetic RD and RP decreases. Major changes in the mechanical strength, microstructure and phase composition of the advanced pebbles were not detected after irradiation.University of Latvia Y9-B044-ZF-N-300; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

    Cloning and endogenous expression of a Eucalyptus grandis UDP-glucose dehydrogenase cDNA

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    UDP-glucose dehydrogenase (UGDH) catalyzes the oxidation of UDP-glucose (UDP-Glc) to UDP-glucuronate (UDP-GlcA), a key sugar nucleotide involved in the biosynthesis of plant cell wall polysaccharides. A full-length cDNA fragment coding for UGDH was cloned from the cambial region of 6-month-old E. grandis saplings by RT-PCR. The 1443-bp-ORF encodes a protein of 480 amino acids with a predicted molecular weight of 53 kDa. The recombinant protein expressed in Escherichia coli catalyzed the conversion of UDP-Glc to UDP-GlcA, confirming that the cloned cDNA encodes UGDH. The deduced amino acid sequence of the cDNA showed a high degree of identity with UGDH from several plant species. The Southern blot assay indicated that more than one copy of UGDH is present in Eucalyptus. These results were also confirmed by the proteomic analysis of the cambial region of 3- and 22-year-old E. grandis trees by 2-DE and LC-MS/MS, showing that at least two isoforms are present. The cloned gene is mainly expressed in roots, stem and bark of 6-month-old saplings, with a lower expression in leaves. High expression levels were also observed in the cambial region of 3- and 22-year-old trees. The results described in this paper provide a further view of the hemicellulose biosynthesis during wood formation in E. grandis

    Comparison of the structure of the plasma-facing surface and tritium accumulation in beryllium tiles from JET ILW campaigns 2011-2012 and 2013-2014

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    In this study, beryllium tiles from Joint European Torus (JET) vacuum vessel wall were analysed and compared regarding their position in the vacuum vessel and differences in the exploitation conditions during two campaigns of ITER-Like-Wall (ILW) in 2011–2012 (ILW1) and 2013–2014 (ILW2) Tritium content in beryllium samples were assessed. Two methods were used to measure tritium content in the samples – dissolution under controlled conditions and tritium thermal desorption. Prior to desorption and dissolution experiments, scanning electron microscopy and energy dispersive x-ray spectroscopy were used to study structure and chemical composition of plasma-facing-surfaces of the beryllium samples. Experimental results revealed that tritium content in the samples is in range of 2·1011^{11}–2·1013^{13} tritium atoms per square centimetre of the surface area with its highest content in the samples from the outer wall of the vacuum vessel (up to 1.9·1013^{13} atoms/cm2^{2} in ILW1 campaign and 2.4·1013^{13} atoms/cm2^{2} in ILW2). The lowest content of tritium was found in the upper part of the vacuum vessel (2.0·1012^{12} atoms/cm2^{2} and 2.0·1011^{11} atoms/cm2^{2} in ILW1 and ILW2, respectively). Results obtained from scanning electron microscopy has shown that surface morphology is different within single tile, however if to compare two campaigns main tendencies remains similar

    The International Sexual Health And Reproductive Health Survey (I-SHARE-1): A Multi-Country Analysis of Adults from 30 Countries Prior to and During the Initial COVID-19 Wave

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    Background: The COVID-19 pandemic forced billions of people to shelter in place, altering social and sexual relationships worldwide. In many settings, COVID-19 threatened already precarious health services. However, there is limited evidence to date about changes to sexual and reproductive health (SRH) during the initial wave of COVID-19 disease. To address this gap, our team organized a multi-country, cross-sectional online survey as part of a global consortium. Methods: Consortium research teams conducted online surveys in 30 countries. Sampling methods included convenience, online panels, and population-representative. Primary outcomes included sexual behaviors, partner violence, and SRH service utilization, and we compared three months prior to and three months after policy measures to mitigate COVID-19. We used established indicators and analyses pre-specified in our protocol. We conducted meta-analyses for primary outcomes and graded the certainty of the evidence using Cochrane methods. Descriptive analyses included 22,724 individuals in 25 countries. Five additional countries with sample sizes <200 were included in descriptive meta-analyses. Results: Respondents were mean age 34 years; most identified as women (15160; 66.7%), cis-gender (19432; 86.6%) and heterosexual (16592; 77.9%). Among 4546 respondents with casual partners, condom use stayed the same for 3374 (74.4%) people and 640 (14.1%) people reported a decline. Fewer respondents reported physical or sexual partner violence during COVID-19 measures (1063/15144, 7.0%) compared to the period before COVID-19 measures (1469/15887, 9.3%). COVID-19 measures impeded access to condoms (933/10790, 8.7%), contraceptives (610/8175, 7.5%), and HIV/STI testing (750/1965, 30.7%). Pooled estimates from meta-analysis indicate during COVID-19 measures, 32.3% (95% CI 23.9-42.1) of people needing HIV/STI testing had hindered access, 4.4% (95% CI 3.4-5.4) experienced partner violence, and 5.8% (95% CI 5.4-8.2) decreased casual partner condom use (moderate certainty of evidence for each outcome). Meta-analysis findings were robust in sensitivity analyses that examined country income level, sample size, and sampling strategy. Conclusion: Open science methods are feasible to organize research studies as part of emergency responses. The initial COVID-19 wave impacted SRH behaviors and access to services across diverse global settings

    Relatório de estágio em farmácia comunitária

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    Relatório de estágio realizado no âmbito do Mestrado Integrado em Ciências Farmacêuticas, apresentado à Faculdade de Farmácia da Universidade de Coimbr

    Taxonomic Check List of Ichthyofaunal Diversity at Hiramandalam Reservoir, Srikakulam Dt. Andhra Pradesh, India

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    The ichthyofaunal investigation revealed that the occurrence of 59 fish species belonging to 11 orders, 23 families, and 39 genera observed Feb 2022 to Jan 2023 at Hiramandalam Reservoir. These fish were transferred to the lab, fixed in glass jars, and then preserved in a 9-10% formalin solution. The fish were identified based on morphometric traits, meristic counts, and descriptive attributes. The fish were identified to the species level using keys for Indian subcontinent fishes. Five of the 59 species are alien. Order cypriniformes was dominant with 24 species which contributed to 40.67% of the total species followed by Siluriformes 12 (20.33%), Anabantiformes 6 (10.16%), Cichliformes with 4 (6.77%), Synbranchiformes 3 (5.08), Anguilliformes.  Beloiniformes, Gobiiformes, and Perciformes each with 02 (3.38%), Osteoglossiforme and Cyprinodontiformes each with 1 (1.69%). Recorded families out of 23, Siluriformes 06 (26.08%), Cypriniformes 05 (21.23%), Anabantiformes 3 (13.04%), Beloiniformes 2 (8.69%), Osteoglossiformes, Cyprinodontiformes, Anguilliformes, Gobiiformies, Synbranchiformes, Cichliformes, and  Perciformes each 01 (4.34%). The taxonomic trophic levels in the current study were classified as omnivores have a highest percentage of 29 (49.15%), followed by the carnivorous 18 (30.50%), and the herbivorous 11 (19.64%). The population Status is highest with common which contributed to 45.76%, 25.42% were rare, abundant which contributed to 19.64% and moderate which contributed to 10.16% in the total taxa. The composition of trophic levels, IUCN status and Shannon - Wiener Diversity Index and a detailed taxonomic account of these species is documented in this pape
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