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791.
IntroductionOzoneplaysacriticalroleintheearth’secologicalbalanceowingtoitsstrongabsorptionofbiologicallydamagingincomingultra... 相似文献
792.
AzaC预处理增加TCDD对特殊细胞P450基因的诱导 总被引:1,自引:0,他引:1
利用RT-PCR检测不同物质诱导细胞的CYP基因 mRNA的表达水平.在HepG2细胞,TCDD能诱导CYP1A1、CYP1B1及CYP1A2基因表达,CYP1A1、CYP1B1基因比CYP1A2基因更容易被诱导,用AzaC处理后CYP1B1基因表达无改变;在A549细胞和SPC-A1细胞,Azac预处理后增加了TCDD对CYP1家族的诱导.也就是AzaC增加了CYP1A1、CYP1A2和CYP1B1基因表达水平.图1表1参10 相似文献
793.
Dennis J. Lye 《Journal of the American Water Resources Association》1987,23(6):1063-1068
ABSTRACT: In rural Northern Kentucky, rainwater is commonly collected from rooftops and stored in cement block cisterns as the sole source of drinking water. Although every cistern system is unique in some aspect of design, use, or maintenance, a bacterial survey of 30 rural Northern Kentucky cistern systems suggests that coliforms and heterotrophic bacteria are common to all types of cistern storage systems. An average of 600 coliforms/ml and 3.6 ± 105 heterotrophic bacteria/ml were detected in water samples from the bottoms of the cistern storage tanks. Bacterial levels in water delivered to household cold tap faucets were similar to the levels found in the storage tanks. When detected, fecal coliforms were recovered throughout the entire system including the household cold tap faucet. Current U.S. regulations for drinking water quality are discussed, with a suggestion that fecal coliform levels may be a more appropriate guideline for interpreting the water quality of individually maintained, nonchlorinated, nonpiped water supplies, such as cistern storage systems. 相似文献
794.
Stephen R. Kessell Meredith W. Potter Collin D. Bevins Larry Bradshaw Bruhe W. Jeske 《Environmental management》1978,2(4):347-363
Recent advances in fire modeling permit quantitative estimations of fire behavior from quantitative inputs that describe the fuel array and conditions, such as weather and site data, under which it will burn. This paper describes the collection, analysis, and stratification of flammable forest fuels data for coniferous forest ecosystems in Montana and then illustrates the resource management application of these data in three areas: the development of the fire behavior model, a determination of the model's sensitivity to input errors as reflected by fire behavior prediction errors, and the development of a fire hazard simulator (TAROT). A new integrated stand simulator, GANDALF, is highlighted.Conclusions center on the need to integrate fire management into the land management planning decision-making process.This work was supported by a USDI National Park Service contract to Gradient Modeling, Inc., a nonprofit research foundation devoted to ecologic research and resource management applications, and by cooperative aid agreements between Gradient Modeling, Inc. and the USDA Forest Service, Intermountain Forest and Range Experiment Station, Northern Forest Fire Laboratory (Fire in Multiple Use Management, R, D, and A Program). 相似文献
795.
796.
污水处理厂污泥中几种典型酚类内分泌干扰物的调查 总被引:3,自引:1,他引:3
采用超声萃取-C18柱富集净化和柱前衍生气相色谱/质谱方法,检测了我国北方某市四个典型污水处理厂不同工艺段污泥中烷基酚和聚氧乙烯醚的几种典型中间降解产物以及双酚A等内分泌干扰物质.2003年,2004年和2006年三年的分析结果表明,所有的污泥样品中都检测到了壬基酚类物质的存在,总浓度范围为1.00-128.45 mg·kg-1之间,在活性污泥中以壬基酚单氧乙烯醚和壬基酚二氧乙烯醚为主,消化污泥和浓缩污泥中则以壬基酚为主.随着时间的推移,这类物质在城市污泥中有逐渐降低的趋势.辛基酚和双酚A都低于检出限. 相似文献
797.
A/A/O微曝氧化沟处理城市污水的工程设计 总被引:3,自引:0,他引:3
以某日处理量为80000m^3城市污水处理厂为例,介绍了A/A/O微曝氧化沟工艺的设计思路及参数选择,能够满足设计要求,且可信度高,有实用参考价值。 相似文献
798.
Certain chemicals possess the potential to modulate endocrine systems, and thereby interfere with reproduction and developmental processes in the wild. We analyzed endocrine disrupters nonylphenol (NP) and bisphenol A (BPA) levels at various sites in Okinawa and Ishigaki Islands, Japan. River-water samples showed undetectable to low concentrations of NP and BPA at most of the sites investigated. However, an appreciable amount of BPA was detected in sediments at one coral reef site. In addition, significant numbers of river sediment samples showed appreciable amounts of NP and BPA. Most of the sampling sites for this study are located within a distance of 1 km from the coral reefs, which are under influence of river-waters to a variable extent. Therefore, influence of endocrine disrupters may have already begun on adjacent coral reefs. Both endocrine disrupters were positively correlated with human population densities, but not with the contents of red soil generated by farm land reformation. Therefore, it is concluded that NP and BPA pollution is a consequence of human waste discharge, both domestic and industrial, and not by agricultural activities. 相似文献
799.
甲型流感病毒H5N1的siRNA设计 总被引:1,自引:0,他引:1
选用了甲型流感病毒10个毒株(全序列)和一个2004年越南毒株(部分序列),采用自己编写的计算机程序sRNAFinder,对每个毒株的6个RNA片段的6个编码序列进行了siRNA设计.结合系统发育重建方法,利用sR-NAFinder的共有序列分析功能,对得到的6101个siRNA分子进行了计算机筛选.结果表明,设计的siRNA的分子,针对np和pb1应该是最有效的,而针对ha和na的siRNA分子设计,需要疾病流行期毒株的最新测序数据;从ns1的数据不能获得很保守的、可作为预防治疗药物的siRNA分子.图1表4参16 相似文献
800.
Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants and is extensively used in electronic equipment, furniture, plastics, and textiles. It is frequently detected in water, soil, air, and organisms, including humans, and has raised concerns in the scientific community regarding its potential adverse health effects. Human exposure to TBBPA is mainly via diet, respiration, and skin contact. Various in vivo and in vitro studies based on animal and cell models have demonstrated that TBBPA can induce multifaceted effects in cells and animals, and potentially exert hepatic, renal, neural, cardiac, and reproductive toxicities. Nevertheless, other reports have claimed that TBBPA might be a safe chemical. In this review, we re-evaluated most of the published TBBPA toxicological assessments with the goal of reaching a conclusion about its potential toxicity. We concluded that, although low TBBPA exposure levels and rapid metabolism in humans may signify that TBBPA is a safe chemical for the general population, particular attention should be paid to the potential effects of TBBPA on early developmental stages. 相似文献