Evidences showing 2,4-D ethyl ester and pencycuron-induced DNA damage in cyanobacteria and detection by PCR

The impact of 2,4-D ethyl ester and pencycuron in inducing DNA damage in three species of cyanobacteria-Anabaena fertilissima, Aulosira fertilissima, and Westiellopsis prolifica as evidenced by PCR-based assays: RAPD and 16S rRNA amplification was examined. Exposure of genomic DNA (in vitro) to pencycuron for 4 days did not produce severe damage in DNA fragments of all three cyanobacterial species whereas exposure to 2,4-D ethyl ester markedly inhibited the template activity of genomic DNA compared to untreated cultures of A. fertilissima. In A. fertilissima a single band of approximately 1000?bp was observed even after 16 days of exposure to 60?ppm pencycuron which suggests that certain segments of DNA are resistant to pencycuron DNA damaging effects. However, a significant effect was observed in the case of W. prolifica for 2,4-D ethyl ester and pencycuron where complete disappearance of fragments was not recorded even after 16 days of incubation and interestingly some new DNA bands were induced. Similar to the effects with RAPD profile, amplification of rRNA was significantly inhibited following exposure of genomic DNA to 2,4-D ethyl ester and pencycuron. Our findings clearly demonstrate that pesticide concentrations affected cyanobacterial DNA and lethality of these microbes might be due to irreversible DNA damage. Thus, it is postulated that PCR assays may be conveniently used for screening DNA damage produced by 2,4-D ethyl ester and pencycuron in all three cyanobacteria examined in this study.     

《地铁设计规范》中自动扶梯和人行楼梯通行能力折减系数的探讨

针对地铁车站中的人员疏散问题,设置5种疏散场景,运用FDS+Evac进行数值模拟,得出各场景下自动扶梯与人行楼梯平均疏散能力和疏散时间,并与《地铁设计规范》中人员疏散时间计算公式得出的结果进行对比分析。研究结果表明:我国现行《地铁设计规范》中自动扶梯和人行楼梯通行能力折减系数取值偏大,宜从0.9调整为0.772。     

崩塌体运动的全过程模拟及工程应用研究

基于颗粒流程序,建立颗粒-颗粒之间和颗粒-墙体之间线性接触刚度模型、滑动模型和带滞后阻尼性质的接触模型,对危岩体崩塌各个运动过程进行数值实验,得出一种比较理想的模拟方法和参数选取方法,对于研究含有多种运动形式的危岩体崩塌复合运动有一定的参考价值。结合工程实例,模拟危岩体自脱离边坡坡面到运动终止的全过程,并说明模拟方法的有效性,预测危岩崩塌体的滑落距离和任意位置处的速度,为选取合理的防治措施提供指导。     

受内压椭圆封闭薄壁截面杆的小变形动力学性质

讨论受内压椭圆封闭薄壁截面杆的小变形动力学性质。把内压产生的应力作为初应力,利用薄壁杆理论和初应力位形上附加变形的线性理论,研究相对初应力位形产生的附加变形控制方程,由此给出小变形动力学性质的定量分析方法和拉压、弯曲、扭转固有频率用内压表示的数值结果。     

向性能化防火规范转变应注意的几个问题

介绍了性能化建筑防火规范产生的背景以及国内外的发展概况。在对国外一些性能化经验进行总结的基础上,重点从建筑物防火安全水平的量化、性能化设计的不确定性、性能化设计方案的验证以及性能化文件的编制和性能化建筑设计、施工到使用各个环节的连续性等方面,讨论了从处方式防火规范向性能化防火规范转变时应该注意的几个问题。结合中国的具体情况,指出其在发展性能化规范中应着力解决的几个问题:正确处理处方式规范和性能化规范两者的关系;积极推动消防相关产品的发展;解决资金来源,加大经费投入;制定工程惯例或设计导则等。     

环境信息分类编码标准化

本文论述了我国环境信息分类编码标准化工作及其重要意义,着重探讨了信息分类的方法,提出了对我国环境信息分类编码工作的意见。      

搅拌棒吸附萃取技术在环境样品分析中的应用

搅拌棒吸附萃取(SBSE)是继固相微萃取(SPME)之后的又一种无溶剂的用于痕量有机物分离和浓缩的技术,其萃取涂层体积大,具有灵敏度高、检出限低、重现性好、不使用有机溶剂等优点。适用于环境样品中挥发性及半挥发性有机物的痕量分析。本文综述了SBSE在环境样品分析中的应用,以及该技术的应用展望。     

Validation of a GC-MS/MS method for simultaneous determination of 86 persistent organic pollutants in marine sediments by pressurized liquid extraction followed by stir bar sorptive extraction

A multiresidue method for the analysis of 86 persistent pollutants in marine sediments at ultra-trace level has been developed and validated using pressurized liquid extraction (PLE) and stir-bar sorptive extraction (SBSE) coupled with thermal desorption and gas chromatography-triple quadrupole mass spectrometry (TD-GC-MS/MS QqQ). The compounds analyzed belong to various families such as polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polybrominated diphenylethers, organophosphorus and organochlorine pesticides and other pesticides such as urons, and triazines. The analytes have very different polarities and log K_ow values, which is an important parameter in the optimization of a SBSE method. Due to PLE high efficiency and throughput rates, along with the proven ability for multiresidue analysis and excellent sensitivity of SBSE, we present an efficient method. The limits of quantification obtained ranged from 0.014 to 1.0 ng g⁻¹, with detection limits below pg g⁻¹ levels. In order to validate the proposed methodology, quality parameters such as recovery, linearity and reproducibility were studied. Recoveries ranged from 63% to 119%, reproducibility (in terms of Relative Standard Deviation for ten determinations) was lower than 35% in all cases, and determination coefficients higher than 0.990 for all analytes. The main factors that affect PLE, SBSE and GC-MS/MS procedures were optimized. The method was applied to the analysis of nine marine sediments obtained from the nine main submarine wastewater discharge points (emissaries) presents along the coast of Tenerife Island (Canary Islands, Spain).     

SBSE-TDU-GC/MS法同步测定饮用水源水中16种多溴联苯化合物

通过对萃取和解吸条件进行优化,实现搅拌棒吸收萃取(SBSE)-热脱附-气相色谱/质谱联用以同时测定饮用水源水中16种多溴联苯单体。此法在2~50 ng/L范围内线性良好,取10 m L水样,搅拌棒吸收萃取1 h后,16种多溴联苯单体的检出限为0.5~1.1 ng/L。对实际水样进行2个质量浓度的加标回收,平均回收率为89.2%~102%。     

青海湖沉积物重金属分布及其潜在生态风险分析

青海湖是我国最大的闭口咸水湖.近年来随着工农业及旅游业的迅速发展,湖泊受人为活动影响不断增加,引起广大学者关注.为了深入了解青海湖表层沉积物中的重金属分布情况,在调查Zn、 Cu、 Pb、 Co、 Ni、 As、 Cd和Cr这8种重金属含量的基础上,对其赋存形态进行了分析,并对其进行来源解析和生态风险评价.结果表明：（1）青海湖表层沉积物重金属除ω（As）(13.21 mg·kg^-1)和ω（Cd）(0.21 mg·kg^-1)超出环境背景值1.13倍和1.53倍,其余6种重金属均不同程度低于环境背景值,从空间分布来看,除As外其他7种重金属元素空间分布特征极为相似,高值主要分布在湖泊西北部及151码头附近;（2）除Cd外其他7种重金属的主要存在形态为残渣态,而Cd主要以生物有效态形式存在,对水生生物具有较高的潜在生物毒性;（3）结合相关性分析和主成分分析,沉积物中Zn、 Cu、 Pb、 Co、 Ni、 Cd和Cr的来源以自然源为主,As的来源则受到农业生产等人为因素影响;（4）根据潜在风险分析结果,青海湖沉积物重金属整体处于轻微生态危害水平,但...