钙对李氏禾富集和耐受铬的调控作用

通过水培实验，研究钙对铬胁迫下李氏禾幼苗生理生化、草酸分泌及铬吸收量的影响，考察钙对李氏禾体内草酸合成的调控，进而促进李氏禾的铬耐性富集能力的作用。结果显示，不同浓度Cr³⁺胁迫下缺钙处理，李氏禾生长受抑制及质膜过氧化作用加剧，体内总草酸含量为对照处理的113%~169%，且主要表现为水溶性草酸含量显著高于对照，水溶性草酸含量为对照处理的135%~197%；高钙处理，李氏禾细胞膜透性、丙二醛（MDA）含量低于对照，李氏禾叶部总草酸含量为对照处理的125%~155%，且主要表现为不溶性草酸含量显著高于对照，其含量为对照处理的181%~270%。低浓度（0.2、0.4 mmol/L）铬胁迫下，高钙处理总铬含量分别为对照处理的175%和215%，高浓度（0.8、1.0 mmol/L）铬胁迫下，总铬含量与对照处理无显著差异（P>0.05）。可见，添加Ca²⁺能在一定Cr³⁺浓度胁迫下，有效缓解铬对李氏禾的毒害，且能通过提高植物体内不溶性草酸含量达到促进植物富集和耐受铬的能力。     

高锰酸钾降解地下水中PCE的研究

以氯代有机污染物中常见的PCE为目标污染物，以自制高锰酸钾溶液为氧化剂，采用批实验方法，探讨了高锰酸钾降解PCE的反应动力学、影响因素以及反应机理。反应结果表明，高锰酸钾降解PCE的反应符合一级动力学方程，反应活化能E为57.119 kJ/mol，在30℃条件下，反应速率常数为0.0076 min^-1，半衰期为91.20 min。在pH在3～10，离子强度在0～0.1030 mol/L之间变化时，反应速率不受明显影响。     

生物法-人工湿地组合工艺处理小城镇混合污水研究

为适应小城镇污水处理高效、低耗、管理简单的要求,开展了生物法(水解酸化/生物接触氧化)-人工湿地组合工艺(A/BCO-CW)处理小城镇片区混合污水的研究。结果表明,A/BCO系统在停留时间为3～6 h条件下,对悬浮物和有机物有高的去除效率,COD、BOD5和TSS去除率分别达到63.1%、67.7%和66.2%,避免了人工湿地堵塞和提高处理效率,减少了所需湿地面积44%。全年运行结果表明,在0.30～0.59 m/d水力负荷率下,垂直流-表面流-水平潜流人工湿地组合系统对COD、BOD5和TSS平均去除负荷达9.4、5.1和7.2 g/(m2.d)(42%、71.2%和85.2%);COD、BOD5去除速率常数为74.6±12.1 m/y、166±30.5 m/y,这些数值均处于文献中k值范围的高量程内。A/BCO-人工湿地系统对COD、BOD5和TSS具有好的处理效果,出水水质能够稳定达到《地表水环境质量标准》(GB 3838-2002)的IV类水标准,2种处理方法有效组合起来,所开发的低成本、高效率、可持续运行的城镇废水处理组合系统,将会在实际应用尤其是高有机负荷污水处理中发挥良好效用。     

Short-term exposure of the European sea bass Dicentrarchus labrax to copper-based antifouling treated nets: Copper bioavailability and biomarkers responses

We studied if the levels of copper released from antifouling treated nets used in finfish mariculture could affect the immune defense mechanism and/or induce oxidative stress in Dicentrarchus labrax, after short term exposure in laboratory experiments. Dissolved copper concentration released from the treated nets, copper bioavailability and a set of biomarkers responses were measured. Biomarkers included hemoglobin concentration, activities of lysozyme, total complement, respiratory burst, glutathione S-transferase and acetycholinesterase and concentration of thiobarbituric acid reactive substances. Results indicated elevated copper concentration in seawater (184 μg L⁻¹) but low concentration in muscle (1.5 μg g⁻¹) and liver (117 μg g⁻¹). Copper bioavailability was independent of copper complexes with dissolved organic carbon. However, formation of copper complexes with other matrices could neither be excluded nor justified. The released copper from the treated nets did not induce oxidative stress but affected the immediate immune defense mechanism of the exposed fish making them more easily vulnerable to diseases. Consequently, copper-based antifouling treated nets could be a risk factor for D. labrax health.     

交通荷载作用下饱和软粘土孔压-应变分析模型

针对交通荷载的作用特点设计了循环三轴试验,进而对交通荷载作用下饱和软粘土的动力特件进行厂研究.结果表明:循环荷载作用下,饱和软粘土存在临界循环应力比,采用孔压曲线所得到的临界循环应力比要小于采用应变曲线所得到的临界循环应力比.当土样不存在初始剪应力时,随着循环次数的增加,土样的应力-应变关系曲线近似原点对称,但随着初始剪应力的增大,应力-应变关系曲线逐渐表现为一系列平行曲线,峰值孔压与循环孔压幅值均逐渐减少;同时,轴应变的发展加快,但循环应变幅值逐渐减小.当循环应力比小于临界循环应力比时,对于同一初始剪应力,不同循环应力比下的孔压比-动应变曲线近似集中在同一条曲线上.通过对试验数据进行回归分析,得到了交通荷载作用下饱和软粘土残余孔压-累积塑性应变关系模型.     

Cytotoxicity and DNA damage of five organophosphorus pesticides mediated by oxidative stress in PC12 cells and protection by vitamin E

Previous studies have demonstrated that pesticides could induce cytotoxicity and genotoxicity in vivo and in vitro, and that oxidative stress may be an important factor involved. However, investigations comparing the capability of different organophosphorous (OP) compounds to induce cytotoxicity, genotoxicity and oxidative stress are limited. Hence, the aim of this paper was to access the cytotoxic and genotoxic effects of five OPs or metabolites, Acephate (ACE), Methamidophos (MET), Chloramidophos (CHL), Malathion (MAT) and Malaoxon (MAO), and to clarify the role of oxidative stress, using PC12 cells. The results demonstrated that MET, MAT and MAO caused significant inhibition of cell viability and increased DNA damage in PC12 cells at 40 mg L^?1. MAO was more toxic than the other OPs. ACE, MET, MAT and MAO increased the levels of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA), and decreased the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) at 20 mg L^?1 and 40 mg L^?1 to different degrees. Pre-treatment with vitamin E(600 μM)caused a significant attenuation in the cytotoxic and genotoxic effect; pre-treatment reversed subsequent OP-induced elevation of peroxidation products and the decline of anti-oxidant enzyme activities. These results indicate that oxidative damage is likely to be an initiating event that contributes to the OP-induced cytotoxicity.     

Photodegradation of sulfonamide antibiotics in simulated and natural sunlight: Implications for their environmental fate

The photochemical fate of seven sulfonamides was investigated in matrices representative of natural water bodies under various light sources. Fundamental photolysis parameters such as molar absorption coefficient, quantum yield (QY) and first-order rate constants were determined. The photolysis decay rate was dependent on the protonation state of the molecule, pH of the water sample and dissolved organic matter. Natural organic matter was the most significant factor in the indirect photolysis of sulfonamides. Half-lives were in the range of minutes at 254 nm to days under natural sunlight. Under natural sunlight, all sulfonamides showed higher removal rates in natural waters implying that indirect photolysis is the predominant mechanism.     

六自由度气锤振动技术与电磁斜面振动技术比较

六自由度气锤振动与电磁斜面振动是两种模拟产品三轴振动的振动技术。由于两种振动技术的机理不同，其对样品的振动影响也会有区别。本文研究讨论两种不同振动技术的不同特点，以及对不同产品的振动效果别，我们可以根据样品特点和测试需求，选择更合适的震动技术。     

预测有机化合物对水蚤EC50值的片段常数法

根据217种化合物建立了估算有机化合物对水蚤EC50值（48h半数影响浓度）的片段常数模型，分析了模型的误差及稳健性。研究结果表明，有机化合物的片段常数和结构因子与水蚤的EC50值倒数的对数（lg1/EC50)显著相关，可以根据片段常数法估算有机化合物对水蚤的EC50。模型的可决系数为0.9687，平均绝对误差0.40个对数单位，其中68.7%化合物的误差小于0.5个对数单位。     

Corynebacterium glutamicum as an indicator for environmental cobalt and silver stress–A proteome analysis

Cobalt and silver are toxic for cells, but mechanisms of this toxicity are largely unknown. Analysis of Corynebacterium glutamicum proteome from cells grown in control and cobalt or silver enriched media was performed by two dimensional gel electrophoresis (2DE) followed by mass spectrometry. Our results indicate that the cell adapted to cobalt stress by inducing five defense mechanisms: Scavenging of free radicals, promotion of the generation of energy, reparation of DNA, reparation and biogenesis of Fe-S cluster proteins and supporting and reparation of cell wall. In response to the detoxification of Ag⁺ many proteins were up-regulated, which involved reparation of damaged DNA, minimizing the toxic effect of reactive oxygen species (ROS) and energy generation. Overexpression of proteins involved in cell wall biosynthesis (1,4-alpha-glucan branching enzyme and nucleoside-diphosphate-sugar epimerase) upon cobalt stress and induction of proteins involved in energy metabolism (2-methylcitrate dehydratase and 1, 2-methylcitrate synthase) upon silver demonstrate the potential of these enzymes as biomarkers of sub-lethal Ag⁺ and Co toxicity.