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.     

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．     

Method to Partition Between Attached and Unattached E. coli in Runoff From Agricultural Lands1

Abstract: Remediation of waters impaired by bacterial indicators is usually dictated by total maximum daily load plans, which are heavily dependent on fate and transport modeling of bacterial indicators. Nonpoint source pollution models are most frequently used to assess bacterial transport to surface waters and most models typically simulate bacterial transport as a dissolved pollutant. Previous studies have found that cells preferentially attach to sediments; however, a variety of techniques have been used to assess attachment including filtration, fractional filtration, and centrifugation. In addition, a variety of chemical and physical dispersion techniques are used to release attached and bioflocculated cells from particulates. Here we developed and validated an easy‐to‐replicate laboratory procedure for separation of unattached from attached E. coli which will also identify particle sizes to which E. coli preferentially attach. Physical and chemical dispersion techniques were evaluated and a combined hand shaker treatment for 10 min followed by dilutions in 1,000 mg/l of Tween 85 significantly increased total E. coli concentrations by 31% when compared with a control. In order to separate unattached from attached fractions, two commonly used techniques, fractional filtration, and centrifugation were combined. The filtration and centrifugation treatments did not reduce E. coli concentrations when compared with a control (p > 0.05), indicating that damage was not inflicted upon the E. coli cells during the separation procedure.     

Isolation and Identification of Enterococci from Seawater Samples: Assessment of Their Resistance to Antibiotics and Heavy Metals

A hundred Enterococcus strains were isolated from seawater samples collected from coastal areas of Istanbul. Isolates were identified to the species level using standard biochemical tests specified by Facklam and Collins. The species distribution was as follows Enterococcus faecalis (96%), Enterococcus gallinarum (3%) and Enterococcus solitarius (1%). The resistance of bacteria to both heavy metals (zinc [Zn], iron [Fe], cadmium [Cd], chrome [Cr], cobalt [Co]) and antibiotics (ampicillin 10 μg [AP], penicillin G 10 Units [PG], gentamycin 10 μg [GM], streptomycin 10 μg [S], chloramphenicol 10 μg [C], erythromycin 15 μg [E], kanamycin 30 μg [K], amikacin 30 μg [AK], nalidixic acid 30 μg [NA], and vancomycin 30 μg [VA]) was evaluated. None of the strains was resistant to VA. It was found that among the 100 isolates, those that exhibit resistance to antibiotics, particularly NA, S and K, were also resistant all the heavy metals tested. To our knowledge this is the first report focusing on determination of resistance of environmental enterococci found in Istanbul against heavy metals and antibiotics. Thus, combined expressions of antibiotic and heavy metal resistance may help to reinforce ecological and epidemiological studies and to determine the role of these strains in antibiotic and heavy metal resistance dissemination.     

基于O/E模型的浅水湖泊生态系统健康评价

以长江中下游阻隔型浅水湖泊为研究对象,分析了1998—2018年116湖次底栖动物野外调查数据,构建了基于预测模型的观测物种组成/期望物种组成(O/E)指数健康评价指标体系,评价了长江中下游浅水湖泊的底栖动物物种组成完整性.O/E指数模型评价结果显示,在物种采集概率(Pc)>0阈值条件下的O/E0模型预测得到的监测湖泊...     

细菌SOD对微生物紫外光辐射损伤的恢复作用

将培养至对数中期的大肠杆菌、钝齿棒杆菌和啤酒酵母等３种微生物的细胞适度稀释液，分别涂布于培养皿上使受紫外光照射，在细胞受辐射后死亡率大于９０％时停止照射，立即加入一定剂量的细菌超氧化物岐化酶（ＳＯＤ），以观察ＳＯＤ对微生物活力的恢复效应．结果表明，ＳＯＤ可使受辐照的细胞存活率显著提高，且量效关系明显，而照前添加ＳＯＤ则无上述效应．检测表明，紫外光照射可引发细菌的超弱发光，且该种超弱发光可因氧气的充入而瞬间增强，鲁米诺也能增强这种超弱发光，加入甘露醇对发光无影响．当紫外光照射后加入ＳＯＤ能使发光强度大为减弱，表明此种超弱发光与的活动有关，并对ＳＯＤ拮抗紫外线杀菌的机理作了讨论．     

额济纳河水质污染特征

对额济纳河历年水质监测数据的分析表明 :额济纳河为四级中度污染水体 ,污染有加重趋势 ;主要污染因子是总硬度、悬浮物 ;流域内水土流失及风沙较多是造成污染的主要因素