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排序方式: 共有55条查询结果,搜索用时 15 毫秒
1.
Alistar Ottochian Chiara Ricca Frederic Labat Carlo Adamo 《Journal of molecular modeling》2016,22(3):61
The diffusion and ionic conductivity of Li x Na1?x CO3 salt mixtures were studied by means of Molecular Dynamics (MD) simulations, using the Janssen and Tissen model (Janssen and Tissen, Mol Simul 5:83–98; 1990). These salts have received particular attention due to their central role in fuel cells technology, and reliable numerical methods that could perform as important interpretative tool of experimental data are thus required but still lacking. The chosen computational model nicely reproduces the main structural behaviour of the pure Li2CO3, Na2CO3 and K2CO3 carbonates, but also of their Li/K and Li/Na mixtures. However, it fails to accurately describe dynamic properties such as activation energies of diffusion and conduction processes, outlining the need to develop more accurate models for the simulation of molten salt carbonates. 相似文献
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B Utete C Phiri SS Mlambo N Maringapasi N Muboko TB Fregene 《African Journal of Aquatic Science》2018,43(1):1-15
Concentrations of aluminium, cadmium, chromium, cobalt, copper, iron, lead, nickel and zinc were determined in surface water, benthic sediments, and the gills, liver and stomach muscle tissues of Oreochromis niloticus and Clarias gariepinus in peri-urban lakes Chivero and Manyame, Zimbabwe. Five sites were sampled in each lake once per month in November 2015, February, May, August and November 2016. Pollution load index detected no metal contamination, whereas the geo-accumulation index reflected heavy to extreme sediment pollution, with Fe, Cd, Zn, Cr, Ni and Cu present in both lakes. Significant spatial temporal variations were detected for Al, Cr, Cu and Pb across sites within and between the two lakes. High Fe, Al and Cr concentrations in water and sediments in lakes Chivero and Manyame derive from geogenic background sources in addition to anthropogenic loads and intensity. Elevated concentrations of Al, Pb, Cu, Cd, Fe and Zn detected in gills, liver and stomach tissue of catfish corroborate concentrations in water and sediments, and pose the highest ecological and health risk for hydrobionts in lakes Chivero and Manyame. Contiguity of peri-urban lakes exposes them to similar threats, necessitating creative water management strategies, which ensure ecological continuity. 相似文献
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We investigated the efficacy of Ocimum basilicum (OB) essential oils for treating depression related behavioral, biochemical and histopathological changes caused by exposure to chronic unpredictable mild stress (CUMS) in mice and to explore the mechanism underlying the pathology. Male albino mice were divided into four groups: controls; CUMS; CUMS plus fluoxetine, the antidepressant administered for pharmacological validation of OB; and CUMS plus OB. Behavioral tests included the forced swim test (FST), elevated plus-maze (EPM) and the open ?eld test (OFT); these tests were performed at the end of the experiment. We assessed serum corticosterone level, protein, gene and immunoexpression of brain-derived neurotropic factor (BDNF) and glucocorticoid receptors (GRs) as well as immunoexpression of glial fibrillary acidic protein (GFAP), Ki67, caspase-3 in the hippocampus. CUMS caused depression in the mice as evidenced by prolonged immobility in the FST, prolonged time spent in the open arms during the EPM test and reduction of open field activity in the OFT. OB ameliorated the CUMS induced depressive status. OB significantly reduced the corticosterone level and up-regulated protein and gene expressions of BDNF and GR. OB reduced CUMS induced hippocampal neuron atrophy and apoptosis, and increased the number of the astrocytes and new nerve cells. OB significantly increased GFAP-positive cells as well as BDNF and GR immunoexpression in the hippocampus. 相似文献
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Elisa F. Long Roshni Mandalia Sundhiya Mandalia Sabina S. Alistar Eduard J. Beck Margaret L. Brandeau 《PloS one》2014,9(4)
Objective
In many high-income countries with low HIV prevalence, significant numbers of persons living with HIV (PLHIV) remain undiagnosed. Identification of PLHIV via HIV testing offers timely access to lifesaving antiretroviral therapy (ART) and decreases HIV transmission. We estimated the effectiveness and cost-effectiveness of HIV testing in the United Kingdom (UK), where 25% of PLHIV are estimated to be undiagnosed.Design
We developed a dynamic compartmental model to analyze strategies to expand HIV testing and treatment in the UK, with particular focus on men who have sex with men (MSM), people who inject drugs (PWID), and individuals from HIV-endemic countries.Methods
We estimated HIV prevalence, incidence, quality-adjusted life years (QALYs), and health care costs over 10 years, and cost-effectiveness.Results
Annual HIV testing of all adults could avert 5% of new infections, even with no behavior change following HIV diagnosis because of earlier ART initiation, or up to 18% if risky behavior is halved. This strategy costs £67,000–£106,000/QALY gained. Providing annual testing only to MSM, PWID, and people from HIV-endemic countries, and one-time testing for all other adults, prevents 4–15% of infections, requires one-fourth as many tests to diagnose each PLHIV, and costs £17,500/QALY gained. Augmenting this program with increased ART access could add 145,000 QALYs to the population over 10 years, at £26,800/QALY gained.Conclusions
Annual HIV testing of key populations in the UK is very cost-effective. Additional one-time testing of all other adults could identify the majority of undiagnosed PLHIV. These findings are potentially relevant to other low-prevalence, high-income countries. 相似文献9.
Typical preparation of seed samples for infrared (IR) microspectroscopy involves imbibition of the seed for varying time periods followed by cryosectioning. Imbibition, however, may initiate germination even at 4° C with associated changes in the chemistry of the sample. We have found that it is possible to section seeds that are sufficiently hard, such as soybeans, on a standard laboratory microtome without imbibition. The use of dry sectioning of unimbibed seeds is reported here, as well as a comparison of different mounting media and modes of analysis. Glycerol, Tissue-Tek, and ethanol were used as mounting media, and the quality of the resulting spectra was assessed. Ethanol was the preferred mountant, because it dried quickly with no residue and thus did not interfere with the spectrum of interest. Analysis in transmission mode using barium fluoride windows to hold the samples was compared with transmission-reflection analysis with sections mounted on special infrared-reflecting slides. The two modes of analysis performed well in different regions of the spectrum. The mode of analysis (transmission vs. transmission-reflection) should be based on the components of greatest interest in the sample. 相似文献