饮用水有机类消毒副产物毒理学研究方法进展

伴随着饮用水消毒技术的改进,有机类消毒副产物(DBPs)的种类日趋多样化,其生物毒性和健康风险受到广泛关注。基于国内外对DBPs毒理学效应的研究成果,结合消毒技术的发展历程,对有机类DBPs进行了系统的分类,针对含碳消毒副产物(C-DBPs)和含氮消毒副产物(N-DBPs)中典型的DBPs的毒理学研究方法进行了详细的介绍,在此基础上分析了相关研究的不足之处和发展趋势,对今后的研究方向提出了建议。     

应用遗传算法建立云杉针叶表面PCDD/Fs光解半衰期的预测模型

采用量子化学PM3算法计算PCDD/Fs的量子化学参数,应用遗传算法(Genetic Algorithm, GA)对所建模型中的变量进行筛选,建立了能预测吸附到云杉[Picea abies (L.) Karst.]针叶表面的PCDD/Fs光解半衰期(t_1/2)的定量结构-性质关系(QSPR)模型,认为影响PCDD/Fs光解速率的主要因素是分子最高占据轨道能(E_HOMO)、前线分子轨道能量差(E_LUMO-E_HOMO)和平均极化率(α).随着EHOMO和α的增大;其lg t_1/2值增大,PCDD/Fs的lg t_1/2值与其(E_LUMO-E_HOMO)值呈抛物线关系,当E_LUMO-E_HOMO＝7.847时,lg t_1/2有最小值;当E_LUMO-E_HOMO≤7.847时,lg t_1/2值随着E_LUMO-E_HOMO的增大而减小;当E_LUMO-E_HOMO≥7.847时,lg t_1/2值随着E_LUMO-E_HOMO的增大而增大.     

Fe/TiO2/ACF三元复合光催化材料联合脉冲放电降解甲基橙

采用溶胶-凝胶法制备了Fe/TiO₂/ACF三元复合光催化材料,将其投入到脉冲放电水处理反应器中降解甲基橙,考察该材料的光催化性能,以及它与脉冲放电的联合降解过程中操作因素的影响. 结果表明,Fe/TiO₂/ACF三元复合光催化材料与脉冲放电产生协同作用,大大提高了对甲基橙的去除率. 甲基橙的去除率与掺铁量〔以摩尔分数计〕、煅烧温度、溶液电导率和pH有关. 当掺铁量为0.07%,煅烧温度为900 ℃时,降解效果最佳;当溶液pH为6,电导率为300 μS/cm时,对Fe/TiO₂/ACF与脉冲放电的联合降解效果有利.      

酚类化合物对小白鼠脾脏细胞DNA毒性的构效相关研究

应用彗星实验技术,测定了12种酚类化合物对小白鼠脾脏细胞DNA的损伤水平.应用Hansch法和量子化学MOPAC-PM3方法计算了12种酚类化合物的辛醇-水分配系数、分子折射率、分子最高占据轨道能和分子中最正原子电荷.运用SPSS统计软件进行回归分析,对小白鼠脾脏细胞DNA的损伤率进行了定量结构-活性相关研究(QSAR).结果表明,酚类化合物的亲脂性参数和分子折射率能有效地表征它们所引起的DNA的损伤程度.由化合物的电性效应引起的细胞毒性可忽略.     

Equilibrium,kinetic, and quantum chemical studies on the adsorption of Congo red using Imperata cylindrica leaf powder activated carbon

Leaf powder of spear grass, otherwise known as Imperata cylindrica (IC), was used to prepare activated carbon. The Imperata cylindrica activated carbon (ICAC) prepared was used for the removal of Congo red (CR) dye from aqueous solution. Operation parameters such as initial dye concentration, contact time, adsorbent dosage, pH, and temperature were studied in batch systems. Equilibrium was attained in 150 and 180?min at lowest and highest concentrations, respectively. Maximum adsorption was observed at pH 3. Quantum chemical studies suggested that the protonation of aniline groups and minimal molecular size at planar geometry coupled with electrostatic interaction enhances the adsorption at low pH. Adsorption data were tested using pseudo-first-order and second-order reaction kinetics; the latter was found to be more suitable with a coefficient of determination of ≥0.99. The adsorption process fits Langmuir isotherm model better than the Freundlich model, with a maximum monolayer coverage of 313?mgg^?1. This study shows that ICAC is effective in removing CR dye from aqueous solutions.     

Identification of Sudan III-(deoxy)-guanosine adducts formed in situ in a reaction with no catalyst

Incubation of guanosine and Sudan III induces the formation of a stable adduct, which may be identified using a spectrophotometric technique and mass spectroscopy. The high nucleophilicity of the C⁸ position and its proximity to N⁷ makes the site susceptible to a nucleophilic attack, which explains the S_N2 reaction detected between guanosine and Sudan III dye. In addition, direct interaction of Sudan III with calf thymus DNA was monitored using a simple spectrophotometric technique. The results presented indicate that a simple modification of the chemical structure of Sudan I (monoazo dye) to Sudan III (diazo dye) markedly alters reactivity towards nitrogenous DNA bases.     

The international toxicity equivalency factor (I‐TEF) method for estimating risks associated with exposures to complex mixtures of dioxins and related compounds∗

The International Toxicity Equivalency Factor (I‐TEF) method of risk assessment is a revised interim procedure for assessing the risks associated with exposures to complex mixtures of chlorinated dibenzo‐p‐dioxins and dibenzofurans (CDDs and CDFs). This updated scheme was developed by a working group of the North Atlantic Treaty Organization's Committee on the Challenges of Modern Society and has been officially adopted by the U.S. Environmental Protection Agency (EPA), Canada, Ontario Ministry of the Environment, the Nordic countries, the Netherlands, and the United Kingdom. Prior to the development of the I‐TEF method, at least ten slightly different schemes had been used throughout the world which complicated communication among scientists and regulatory agencies concerning the toxicological significance of complex mixtures of CDDs and CDFs. The I‐TEF approach facilitates risk communication internationally by reducing large volumes of analytical data into a single number‐International Toxicity Equivalents (I‐TEQ). As a result, the I‐TEF method represents an improvement in an already useful risk assessment/regulatory tool.     

Accomplishments of the NATO/CCMS pilot study on international information exchange on dioxins and related compounds∗

A project promoting the international exchange of information on chlorinated dibenzo‐p‐dioxins and dibenzofurans (CDDs and CDFs) was conducted under the auspices of the Committee on the Challenges of Modern Society (CCMS) of the North Atlantic Treaty Organization (NATO). Initiated in 1985, the Pilot Study on International Information Exchange on Dioxins and Related Compounds was a three‐year effort to improve the state of the art of dioxin research, regulation, and technology by encouraging collaboration among interested countries and organizations. Participating nations included Canada, Denmark, the Federal Republic of Germany, Italy, the Netherlands, Norway, the United Kingdom, and the United States. Numerous activities were accomplished to promote information exchange so that better informed decisions can be made concerning future research activities and resource allocations. Three major areas were addressed: Exposure and Hazard Assessment, Technology Assessment, and Management of Accidents. A total of 15 CCMS reports were published which summarize the achievements of the Pilot Study.     

量子粒子群优化算法在结构参数识别中的应用

系统识别问题可以转化成一高维多模优化问题。针对基本粒子群优化在分析此类问题时容易出现早熟收敛从而导致局部优化和较大误差的缺陷,提出将量子粒子群优化算法(QPSO)应用于结构参数识别。QPSO具有参数少、编程简单、易实现、收敛速度快、可以避免早熟收敛、能够迅速在全局找到最优解的特点。本文在测量数据不完备且含噪声污染,参数质量、刚度和阻尼等信息缺乏的情况下,通过数值模拟以及在真实结构参数识别中的应用,验证了QPSO的有效性。     

基于QPSO-RBF的瓦斯涌出量预测模型

为了提高径向基(RBF)网络预测瓦斯涌出量的泛化能力,提出QPSO-RBF模型。该模型采用量子粒子群(QPSO)算法优化RBF网络隐层基函数中心、扩展系数以及输出权等初始参数,将网络参数编码为QPSO学习算法中的粒子个体,在全局空间中搜索最优适应值参数。其中,RBF网络选取5-3-1的精简结构,采用5个变量作为影响因子预测瓦斯涌出量。结果表明,经QPSO优化后的RBF网络模型预测结果稳定且唯一,其泛化指标平均相对变动值(ARV)为0.012 2。与PSO-RBF、RBF模型预测结果比较,QPSO-RBF模型的泛化能力和网络训练速度优于前2种;预测精度约为PSO-RBF模型的1.5倍、RBF模型的4倍。