电化学消毒法对水中大肠杆菌的灭活特性

本研究通过电化学消毒小试装置,系统考察了电极板材料、极板间距、p H、水温、Na Cl浓度等因素对水中大肠杆菌CGMCC 1.3373灭活效果的影响,并进一步考察了电化学消毒对抗生素抗性大肠杆菌CGMCC 1.1595的灭活效果及其抗性变化.结果发现,在相同的电化学消毒条件下,阳极采用钌铱涂层的钛电极板的灭活效果显著优于铅涂层和铱钽涂层电极板,并且极板间距为50 mm时灭活率最高.进一步研究表明,电化学消毒法对大肠杆菌的灭活率随水的p H升高而降低,随水温和Na Cl浓度升高而升高.在相同消毒条件下,电化学法对四环素抗性大肠杆菌的灭活率显著低于普通大肠杆菌.消毒后存活的抗性菌对四环素、青霉素、氯霉素的抗性,随消毒时间延长呈现先下降后上升的规律.     

美军电磁环境效应(E3)实验室建设浅析

对美军E3实验室建设情况进行了介绍,重点对美国海军航空作战中心及美国海军水面作战中心达尔格伦分部的E3实验室建设进行了介绍和剖析,对美军E3实验室试验设施进行了总结,分析了美军E3实验室建设的特点,有利于深刻认识美军E3实验室建设的发展状况,对我国E3实验室建设有一定的启示作用.     

Evaluation of vitamin E and calcium effects on fluoride toxicity-induced fertility impairment

Chronic fluoride (Fl) toxicity is a serious public health problem globally where drinking water contains more than 1 ppm of Fl. Sodium fluoride (NaF) produced male reproductive system toxicity. The aim of the present study was to evaluate the amelioration of Fl toxicity-induced fertility impairment by vitamin E and calcium during the withdrawal period. The study was carried out on 70 adult male albino rats divided into five main groups: group I control; subdivided into group Ia (maintained on standard diet and water ad libitum for 60 days) and group Ib (maintained on standard diet and water ad libitum for 120 days), group II was administered NaF and subdivided into group IIa (administered NaF for 60 day and sacrificed) and group IIb (administered NaF for 60 day then maintained on standard diet and water ad libitum for a further 60 days), and treated groups III, IV, and V were administered NaF. Rats were maintained during withdrawal from NaF, on vitamin E (10 mg kg^?1 day^?1 for 60 days), calcium (50 mg kg^?1 day^?1 orally for 60 days), and both vitamin E and calcium, respectively. The duration of NaF administration was 60 days at a dose 20 mg kg^?1 day^?1 for all treated groups. The following parameters were determined: body and organ weights, sperm motility, sperm morphology, sperm viability, fertility test, and hormone assays: testosterone, in vitro testosterone production, luteinizing hormone, and follicular stimulating hormone. The combined administration of vitamin E and calcium during withdrawal from NaF showed significant improvement from chronic FL-induced toxicity on male reproductive organs.     

Biological effects of selenium and relationships with carcinogenesis†

Selenium is an element that is both essential, at low levels of dietary intake, and toxic, at high levels, to man and a wide range of animals. The purpose of the communication is to review the evidence for the involvement of hyper‐ and hypo‐selenosis in the aetiology of cancer. High levels of selenium intake have been blamed for an increase in cancer, dental caries and an array of other conditions. Critical evaluation of the evidence, however, leads to the conclusion that such claims have little substance. On the other hand, low levels of selenium intake may be associated with an increased incidence of certain forms of cancer and there appears to be an inverse relationship between blood selenium levels and cancer death rate in the United States. Keshan Disease, in the People's Republic of China has only been shown to occur in populations severely depleted of selenium. In well nourished populations there is no evidence to indicate that selenium supplements have any prophylactic or therapeutic benefit against human diseases such as cancer, cardiovascular disease or cystic fibrosis.     

Genetic toxicology of metal compounds: An examination of appropriate cellular models †

Bacterial systems have not had success predicting metal carcinogenicity. Hypotheses explaining this failure are examined. Using a broad genetic endpoint, λ prophage induction, under sub‐toxic growing conditions, genotoxicity is seen for compounds of chromium, manganese, lead, molybdenum and tungsten. Copper, manganese, arsenic and molybdenum compounds enhanced UV mutagenesis in E. coli WP2.

The toxicity of metal compounds to cultured mammalian cells correlates well with rat oral LD₅₀ values. Whereas insolubility can present problems in bacterial studies, concentrations of metal compounds toxic to mammalian cells can be determined even in the presence of precipitate, and sometimes [Pb(NO₃)₂, BaCl₂ and BeCl₂] occurs only in its presence. PbS and MnS, which are insoluble, are much more toxic than the more soluble compounds Pb(NO₃)₂ and MnCl₂. These results demonstrate the importance of cellular phagocytosis of insoluble metal compounds as a factor in studying the toxicity and genotoxicity of metal compounds.     

铁磁性纳米材料的制备及对17β-雌二醇的选择性富集——基于分子印迹技术

将铁磁性分离与分子印迹技术结合,以四氧化三铁纳米颗粒为核,以17β-雌二醇(E2)为模板分子,3-氨基丙基三乙氧基硅烷(APTES)为功能单体,利用表面聚合法制备了E2分子印迹纳米材料(MIPs)和不含E2的非印迹纳米材料(NIPs).通过傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)、X射线光电子能谱(XPS...     

Dynamics of global oil prices,exchange rate and precious metal prices in India

This study examines cointegration and Granger causality among global oil prices, precious metal (Gold, Platinum and Silver) prices and Indian Rupee–US Dollar exchange rate using daily data spanning from 2nd January 2009 to 30th December 2011. ARDL bounds tests indicate that the series are cointegrated. Toda–Yamamoto version of Granger causality has been employed to establish the causation amongst the variables. The study also examines generalized error variance decomposition of variables due to various shocks in the system. Such information provides insight into the transmission links between the global oil market and the Indian precious metals and foreign exchange market. These have the potential for significant impact in further research, portfolio management and central bank policy design.     

New hydroepidemiological models of indicator organisms and zoonotic pathogens in agricultural watersheds

Simple analytical models are derived to assess how a series of cattle animal farms affect the transport and fate of an indicator organism (Escherichia coli) and a zoonotic pathogen (Campylobacter) in a stream. Separate steady-state mass-balance models are developed and solved for the ultimate minimum and maximum concentrations for the two organisms. The E. coli model assumes that the organism is ubiquitous and abundant in the animals’ digestive tracts. In contrast, a simple dose-response model is employed to relate the Campylobacter prevalence to drinking water drawn from the stream. Because faecal indicators are commonly employed to assess the efficacy of best management practice (BMP) interventions, we also employ the models to assess how BMPs impact pathogen levels. The model provides predictions of (a) the relative removal efficacy for Campylobacter and (b) the prevalence of Campylobacter infection among farm animals after implementation of BMPs. Dimensionless numbers and simple graphs are developed to assess how prevalence is influenced by a number of factors including animal density and farm spacing. A significant outcome of this model development is that the numerous dimensional input and parameter variables are reduced to a group of just four dimensionless Campylobacter-related quantities, characterizing: animal density; in-stream attenuation; animal-to-animal transmission; and infection recovery. Calculations reveal that for some constellations of these four quantities there can be a greater-than-expected benefit in that the proportional reduction of stream Campylobacter concentrations post-BMP can substantially exceed the proportional reduction of concentrations of E. coli in that stream. In addition, a criterion for system sterility (i.e., the conditions required for the farm infection rate to decrease with downstream distance) is derived.     

新体制下装备环境适应性试验鉴定的思考

通过分析现行装备环境工程工作与新体制下试验鉴定要求的差距,归纳提出了新体制下装备环境适应性试验鉴定的总体解决思路,明确了全寿命周期装备环境适应性工作项目剪裁方法,以及完整的装备试验鉴定工作项目集,给出了装备环境适应性要求确定原则,以及各阶段、各层级产品环境适应性要求集,为装备面向实战、全过程、全层级、全指标的环境适应性试验鉴定提供了指导。     

拟南芥VTE1过量表达可以增加维生素E含量和提高烟草植株耐盐行

维生素E在动物细胞内具有抗氧化等重要作用，但在植物体内的功能却鲜为人知．本实验利用CaMV 35S启动子与来源于拟南芥的编码生育酚环化酶（TC）的cDNA（VTE1）构建的嵌合表达载体，以根癌农杆菌介导的叶盘法转化烟草W38．实验结果表明，具有卡那霉素抗性的再生植株经RT-PCR检测，得到了与阳性对照一致的495bp的目标片段；转基因植株的VE含量比对照植株高2倍左右，个别株系高达11倍．实验还发现，在耐盐性实验中转基因植株对盐的抗性明显高于野生型烟草；同时，在不同盐浓度（150、250mmoL／L）胁迫下转基因植株VE含量比未转化植株增加了1．3～1．8倍，首次证明VTE1与植物耐盐性之间的关系．