多氯联苯对离体人红细胞的毒性机理

本实验研究了多氯联苯(PCB_s)对人离体红细胞自由基生成和脂质过氧化作用的影响。红细胞悬液在含有不同剂量Aroclorl254的培养液中37℃温育一定时间,然后测定超氧阴离子自由基(O_2~-)、丙二醛(MDA)、超氧化物歧化酶(SOD)和还原型谷胱甘肽(GSH)的含量。测定结果表明,红细胞脂质过氧化作用与PCB_s存在着剂量——效应及时间——效应关系,Aroclorl254可以直接诱导离体人红细胞的脂质过氧化作用。其中O_2~-、MDA、GSH 3项指标均有良好的剂量——效应及时间——效应关系,SOD活力在温育后迅速增加,之后基本稳定,9h后活力出现下降。     

羟基自由基氧化法在饮用水后处理中的应用

该文分析了饮用水消毒的现状，提出保持氯消毒不变，用羟基自由基氧化法对饮用水进行后处理，去除氯消毒产生的卤代烃，以提高饮用水的质量。     

浅谈环境行政自由裁量权

准确运用环境行政自由裁量权是各级环境保护行政主管部门依法行政的一个重要方面。通过阐述环境行政自由裁量权的概念、合理性的界定，提出环境保护行政主管部门应从坚持立法目的、正当考虑、保持连续性等方面规范自由裁量权的行政行为。     

高级氧化技术在废水处理中的应用研究进展

探讨了高级氧化技术（Ａｄｖａｎｃｅｄ Ｏｘｉｄａｔｉｏｎ Ｐｒｏｃｅｓｓｅｓ，即ＡＯＰｓ）如：Ｏ３／Ｈ２Ｏ２Ｆｅｎｔｏｎ试剂均相湿式催化氧化；Ｈ２Ｏ２／ＵＶ、Ｏ３／ＵＶ、Ｏ３／Ｈ２Ｏ２／ＵＶ均相光催化氧化；多相湿式催化氧化，多相光催化氧化，多相催化和生化氧化等过程处理废水及其反应机理，论述了ＡＯＰｓ技术在工业废水处理方面的研究进展。     

Fenton试剂在染料废水处理中的应用

介绍了Fenton试剂及类Fenton试剂的氧化机理 ,并结合自己所做的实验阐述了Fenton试剂在染料废水处理中的应用。本实验以甲基橙溶液模拟偶氮类染料废水 ,用Fenton法进行处理 ,探讨了H2 O2 和FeSO4·7H2 O的用量、溶液的pH值、溶液的初始浓度、反应时间等对甲基橙剩余率的影响 ,并探讨了甲基橙的降解反应动力学方程。     

甲醛致DNA断裂作用的机制及修复的研究

应用单细胞凝胶电泳技术研究了甲醛致DNA断裂作用、作用机制以及断裂的修复.结果表明,甲醛在低浓度下可以诱导DNA的断裂(P<0.01);该断裂作用可以显著地被羟基自由基(·OH)清除剂甘露醇和二甲基亚砜抑制(P<0.01),以及受到超氧阴离子自由基(O·-2)清除剂超氧化物歧化酶(SOD)显著抑制(P<0.01),但其抑制效果要弱于甘露醇和二甲基亚砜.甲醛引起DNA断裂作用是通过活性氧自由基介导的,且在90min时基本上可被完全修复.     

关于弹性地基上圆环形薄板振动问题的解答

对弹性地基上圆环形薄板的振动问题进行了分析和求解,给出了计算固有频率的计算公式和必要的数据,所考虑的边界条件是内外周边固支和内外周边简支两种情况,外径与内径的比值是2.5,3.0,3.5,4.0,4.5,5.0六种情况.     

高压电晕放电对五氯酚的降解研究

研究了放电电压、溶液pH等因素对高压电晕放电降解PCP效果的影响,并对高压电晕放电处理PCP的动力学进行了初步探讨,同时对高压电晕放电降解PCP的COD和TOC的变化进行了分析。结果表明:放电电压和溶液pH值对PCP降解性能影响很大,放电电压和溶液pH值越高,PCP的降解速度越快。当溶液pH值为11.2、PCP初始质量浓度40 mg/L、电晕放电电压为25 kV时,经30 min电晕放电,PCP的降解率达90%以上,电晕放电降解PCP的反应符合一级反应动力学。在氧化过程中PCP可能转化为苯醌等中间产物,TOC几乎无变化,PCP分解成的小分子有机物使COD升高,可生化性提高。     

Using polarized muons as ultrasensitive spin labels in free radical chemistry

In a chemical sense, the positive muon is a light proton. It is obtained at the ports of accelerators in beams with a spin polarization of 100%, which makes it a highly sensitive probe of matter. The muonium atom is a light hydrogen isotope, nine times lighter than H, with a muon as its nucleus. It reacts the same way as H, and by addition to double bonds it is implemented in free radicals in which the muon serves as a fully polarized spin label. It is reviewed here how the muon can be used to obtain information about muonium and radical reaction rates, radical structure, dynamics, and local environments. It can even tell us what a fragrance molecule does in a shampoo.     

Degradation of sulfonamides and formation of trihalomethanes by chlorination after pre-oxidation with Fe(VI)

Sulfonamides are used in human therapy, animal husbandry and agriculture but are not easily biodegradable, and are often detected in surface water. Sulfamethazine (SMZ) and sulfadiazine (SDZ) are two widely used sulfonamide antibiotics that are used heavily in agriculture. In this study, they were degraded in an aqueous system by chlorination after pre-oxidation with ferrate(VI) (Fe^VIO₄^2 ?, Fe(VI)), an environmentally friendly oxidation technique that has been shown to be effective in degrading various organics. The kinetics of the degradation were determined as a function of Fe(VI) (0–1.5 mg/L), free chlorine (0–1.8 mg/L) and temperature (15–35°C). According to the experimental results, SMZ chlorination followed second-order kinetics with increasing Fe(VI) dosage, and the effect of the initial free chlorine concentration on the reaction kinetics with pre-oxidation by Fe(VI) fitted a pseudo-first order model. The rate constants of SDZ and SMZ chlorination at different temperatures were related to the Arrhenius equation. Fe(VI) could reduce the levels of THMs formed and the toxicity of the sulfonamide degradation systems with Fe(VI) doses of 0.5–1.5 mg/L, which provides a reference for ensuring water quality in drinking water systems.     

植物体游离脯氨酸对SO_2＋NO_2复合物的反应

以大豆、蕃茄、青菜为试验植物，应用开顶式熏气装置，研究了ＳＯ２＋ＮＯ２复合熏气对３种植物游离脯氨酸的影响及其与伤害程度的关系。结果表明，受ＳＯ２＋ＮＯ２熏气的３种植物体内脯氨酸部有增加。其变比规律因植物种类和处理方式而异；脯氨酸的增加率与叶伤害率呈正相关关系。文章初步认为植物体游离脯氨酸可以作为指示污染物的一项生化指标。     

中国自贸区谈判环境与贸易问题分析

许多国家正将主要经贸政策重点转向自贸区,环境与贸易成为自贸区谈判的重要内容。我国应该抓住自贸区环境服务贸易谈判的重要机遇,加快中国经济又好又快发展及环境服务业战略转型。当前需要:加强自贸区谈判对环境及可持续发展的影响研究,解决战略转型的可持续性问题;加强不同环境服务分类影响研究,解决战略转型的对象问题;实施国内环境服务企业的走出去战略,解决战略转型的途径问题;加快环境服务业发展和战略转型的法规和政策体系建设,制定针对国内环境服务企业的扶持战略,解决战略转型的保障问题。     

The obstetrician's view: ethical and societal implications of non-invasive prenatal diagnosis

We believe non-invasive prenatal diagnosis is about to have a massive impact on the way fetal medicine is practised. There will be many great advantages and improvements, but the technology also has the potential to be used for non-medical reasons such as sex selection and paternity testing. We discuss some of the issues that may face obstetricians in the future as a result of this emerging technology. Copyright © 2006 John Wiley & Sons, Ltd.     

First-trimester free beta (hCG) screening for Down syndrome

Maternal serum free beta (hCG) levels are elevated (median 2·20 MOM) in the first trimester of pregnancy in 38 Down syndrome cases as compared with appropriate controls. This observation may form the basis for its use as a marker in screening for Down syndrome in the first trimester. Altered levels of the free beta analyte are observed in pregnancy conditions or complications other than Down syndrome.     

Selected dark sides of biomass-derived biochars as environmental amendments

With the rapid increase in the application of biochars as amendments, studies are needed to clarify the possible environmental risks derived from biochars to use safely the biomass resources. This work reported selected dark sides of maize straw-and swine manurederived biochars pyrolyzed at 300 and 500°C. During the pyrolysis processes, total heavy metals in the biochars were enriched greatly accompanying with considerable emission of the heavy metals into atmosphere and the trends became increasingly obvious with pyrolysis temperature. Meanwhile, the biochars showed distinctly decreased available heavy metals compared with raw feedstocks, which could be mainly attributed to the sorption by the inorganics in the biochars. The water-and acid-washing treatments significantly increased the releasing risks of heavy metals from biochars into the environments. Electron paramagnetic resonance analysis indicated that persistent free radicals, emerged strongly in the biochars as a function of the aromatization of biomass feedstocks, were free from the influence of water-, acid-, or organic-washing of the biochars and could remain stable even after aged in soils for 30 days. Dissolved biochars, highly produced during pyrolysis processes, showed distinct properties including lower molecular weight distribution while higher aromaticity compared with soil dissolved organic carbon.The results of this study provide important perspectives on the safe usage of biochars as agricultural/environmental amendments.     

多层自由旋线分离器的提效增阻作用

文章采用多层旋线布置方式实现了自由旋线分离器分离效率的有效提升,并讨论了多层布置对除尘效率与压力损失的影响规律.在风量2 000 m3/h、液气比0.03 L/m3和粉尘质量浓度1 000 mg/m3的试验条件下,单层旋线和双层旋线的除尘效率均随旋线根数和转速的增加而增加,且双层旋线的除尘效率的增幅高于单层旋线.当旋线...     

Modified ADM1 for modeling free ammonia inhibition in anaerobic acidogenic fermentation with high-solid sludge

Anaerobic acidogenic fermentation with high-solid sludge is a promising method for volatile fatty acid (VFA) production to realize resource recovery. In this study, to model inhibition by free ammonia in high-solid sludge fermentation, the anaerobic digestion model No. 1 (ADM1) was modified to simulate the VFA generation in batch, semi-continuous and full scale sludge. The ADM1 was operated on the platform AQUASIM 2.0. Three kinds of inhibition forms, e.g., simple inhibition, Monod and non-inhibition forms, were integrated into the ADM1 and tested with the real experimental data for batch and semi-continuous fermentation, respectively. The improved particle swarm optimization technique was used for kinetic parameter estimation using the software MATLAB 7.0. In the modified ADM1, the K_s of acetate is 0.025, the k_m,ac is 12.51, and the K_{I_NH3} is 0.02, respectively. The results showed that the simple inhibition model could simulate the VFA generation accurately while the Monod model was the better inhibition kinetics form in semi-continuous fermentation at pH 10.0. Finally, the modified ADM1 could successfully describe the VFA generation and ammonia accumulation in a 30 m³ full-scale sludge fermentation reactor, indicating that the developed model can be applicable in high-solid sludge anaerobic fermentation.     

Potential factors and mechanism of particulate matters explosive increase induced by free radicals oxidation

Atmospheric particulate pollution in China has attracted much public attention. Occasionally, the particle number concentration increases sharply in a short time period, which is defined as a “particulate matter explosive increase”. Heavy particulate matter pollution not only reduces visibility but also has an adverse effect on human health. Hence, there is an urgent need to discover the causes of particulate matter explosive increase. During this campaign, the particle number concentration and free radicals were measured at a tall building on the campus of Lanzhou University of Technology. Additionally, we examined a series of chemicals to reproduce the observed particulate matter explosive increase in a smog chamber to determine its potential factors. Then, we analyzed the mechanism of particulate matter explosive increase in the presence of free radicals. We found that, among the potential inorganic and organic sources analyzed, a mixture of organic and SO₂ in the research region had a major effect on particulate matter explosive increase. Moreover, free radical oxidation has a large effect, especially in the formation of organic particulates.     

Protecting the photosynthetic performance of snap bean under free air ozone exposure

Tropospheric ozone(O_3) is a major air pollutant and causes serious injury to vegetation. To protect sensitive plants from O_3 damage, several agrochemicals have been assessed,including cytokinin(e.g., kinetin, KIN) and ethylenediurea(EDU) with cytokinin-like activity.In higher plant, leaves are primarily injured by O_3 and protective agrochemicals are often applied by leaf spraying. To our knowledge, the mitigating abilities of EDU and KIN have not been compared directly in a realistic setup. In the present research, impacts of elevated O3(2 × ambient O_3, 24 hr per day, for 8 days) on an O_3 sensitive line(S156) of snap bean(Phaseolus vulgaris), which is often used for biomonitoring O_3 pollution, were studied in a free air controlled exposure system. The day before starting the O_3 exposure, plants were sprayed with a solution of EDU(300 ppm), KIN(1 mmol/L) or distilled water, to compare their protective abilities. The results demonstrated that 2 × ambient O_3 inhibited net photosynthetic rate and stomatal conductance, increased the minimal fluorescence yield of the dark-adapted state, decreased the maximal quantum yield of PSII photochemistry, and led to visible injury. KIN and EDU alleviated the reduction of the photosynthetic performance, and visible injury under O_3 fumigation. The plants sprayed with EDU showed greater ability to mitigate the O_3 damage than those sprayed with KIN. Chlorophyll fluorescence imaging may have detected more precisely the differences in O_3 response across the leaf than the conventional fluorometer.     

Inhibition factors and Kinetic model for ammonium inhibition on the anammox process of the SNAD biofilm

The aim of the present work was to evaluate the anaerobic ammonium oxidation (anammox) activity of simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm with different substrate concentrations and pH values. Kaldnes rings taken from the SNAD biofilm reactor were incubated in batch tests to determine the anammox activity. Haldane model was applied to investigate the ammonium inhibition on anammox process. As for nitrite inhibition, the NH₄⁺-N removal rate of anammox process remained 87.4% of the maximum rate with the NO₂⁻-N concentration of 100 mg/L. Based on the results of Haldane model, no obvious difference in kinetic coefficients was observed under high or low free ammonia (FA) conditions, indicating that ammonium rather than FA was the true inhibitor for anammox process of SNAD biofilm. With the pH value of 7.0, the r_max, Ks and K_I of ammonium were 0.209 kg NO₂⁻-N/kg VSS/day, 9.5 mg/L and 422 mg/L, respectively. The suitable pH ranges for anammox process were 5.0 to 9.0. These results indicate that the SNAD biofilm performs excellent tolerance to adverse conditions.