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111.
砷是农田土壤重金属污染的主要元素之一,在砷污染农田土壤的修复过程中往往忽视纳米颗粒能够使结合态的砷重新释放,导致有效态砷浓度升高,探究土壤中黏土矿物对氧化石墨烯(Graphene Oxide,GO)和五价砷(As(V))在多孔介质中迁移行为的影响,对进一步完善农田土壤砷修复理论以及提高农作物产量、保护人体健康具有重要意义。该研究利用蒙脱石和高岭石改性石英砂,通过砂柱迁移试验系统地研究了GO、As(V)和GO-As(V)在填加0%、10%、30%和50%的蒙脱石和高岭石改性石英砂柱中的迁移行为。研究结果表明,随着高岭石和蒙脱石改性石英砂填加比例的增加,GO和As(V)的迁移能力均呈降低趋势,且GO和As(V)在不同条件下的迁移曲线均存在显著差异(P0.05);GO在50%高岭石和蒙脱石改性石英砂柱中的回收率相对于石英砂柱分别下降了14%和17%,As(V)分别下降了15%和12%;在共迁移试验中,GO和As(V)在石英砂柱中回收率分别上升至99%和100%。分析表明,As(V)在蒙脱石改性石英砂柱中的迁移能力大于高岭石改性石英砂,而GO与之相反;当GO和与As(V)共迁移时,二者在介质中的迁移能力均大于其单独迁移。本研究表明GO、As(V)释放到土壤后,能够加速As(V)的迁移,造成土壤砷污染的扩大化。 相似文献
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Waterless live fish transportation is an alternative and promising transport strategy, which may reduce shipping costs, increase stocking density and improve survival of some species. Spotted sea bass is one of the most economically important marine fish in China. However, waterless transportation has not yet been studied on spotted sea bass. To explore the possibility of waterless transportation of spotted sea bass and its sublethal stress responses, the survival rate and dynamics of blood biochemical parameters were evaluated in the present study by preserving it under no water, less water and water (control) conditions for 9 hr. The serum biochemical parameters including total protein, cortisol, glucose, lactate, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total carbon dioxide (TCO2), creatinine, blood urea nitrogen (BUN), ammonia, superoxide dismutase (SOD) activity and malonaldehyde (MDA) were investigated. Results showed that the survival rates of fish in all groups gradually declined with time increasing. At the end of transportation, the survival rates in the control group, less‐water group and no‐water group decreased to 49.11%, 15.60% and 23.96% respectively. Significant changes were observed in several selected serum biochemical parameters, including glucose, lactate, ALT, TCO2, BUN and ammonia during simulated waterless transportation, which might negatively affect the physiological homeostasis of fish, leading to the high mortality in present study. In general, waterless transportation of spotted sea bass was possible, but it might be rather suitable for short time than long time. 相似文献
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Khemiss F Ahmadi S Massoudi R Ghoul-Mazgar S Safta S Moshtaghie AA Saïdane D 《Fish physiology and biochemistry》2009,35(3):541-549
The everted gut sac technique has been used to investigate the effect of Vibrio vulnificus on water and electrolyte (Na+, K+, Cl−, HCO3
−) transport on the intestine of sea bream (Sparus aurata L.). Both the anterior and the posterior intestine were incubated in a medium containing 108
V. vulnificus cells ml−1 at 25°C for 2 h. The presence of V. vulnificus resulted in a significant reduction (P < 0.05) of water absorption in the anterior intestine, while sodium absorption in the anterior (P < 0.01) and posterior (P < 0.05) intestine was elevated. Chloride absorption was increased, but the changed was not significant, while potassium absorption
decreased significantly (P < 0.05), but only in the posterior intestine. Incubation the sea bream intestine with V. vulnificus did not affect carbonate secretion in the anterior segment, whereas high secretion was stimulated in the posterior segment
(P < 0.01). Histological evaluations demonstrated damage in the anterior intestine of sea bream that was characterized by the
detachment of degenerative enterocytes, alterations in the microvilli, and the presence of a heterogenous cell population,
indicating inflammation. Based on our results, we conclude that V. vulnificus caused cell damage to the intestine of sea bream and that the anterior intestine is more susceptible than the posterior part
of the intestine. Several hypotheses are suggested to explain our observations, such as the presence of higher numbers of
villosities in the anterior intestine than in the posterior one and/or the presence of endogenous bacteria in the posterior
intestine which may have a protector role. 相似文献
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The shortcomings of the present two formulae for describing column holdup are analyzed and deductions are made to find a new formula. The column holdup, Hw, described by the new formula is dimensional,and related to soil solute transport kinesis and column physical properties. Compared with the other two column holdups, Hw is feasible to describe dimensional column holdup during solute transport process. The relationships between Hw and retardation factor, R, in different solute transport boundary conditions are established. 相似文献
120.
We studied some clinical, biochemical and haematological variables in Desert (Najdi) sheep acutely stressed in the course of individual road transportation, and the influence thereon of pretreatment with tyrosine. Transportation for 30 min resulted in variable but statistically insignificant increases in heart, pulse and respiratory rates. It also caused significant increases in the plasma concentration of cortisol (from 43.5 to 101.7 mmol/L) and glucose (from 3.1 to 4.5 mmol/L), and a decrease in that of magnesium (from 0.85 to 0.72 mmol/L). The endogenous thiocyanate level was unaffected. The transportation stress also decreased the haematocrit (PCV) and the number of lymphocytes, and increased the concentration of haemoglobin. Pretreatment of sheep with tyrosine at a dose of 100 mg/kg by the intravenous route significantly ameliorated the stress-induced clinical, biochemical and haematological changes. The treatment caused no overt adverse effects. 相似文献