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211.
212.
Helmut W. Fischer Susanne Ulbrich Daniela Pittauerov Bernd Hettwig 《Journal of environmental radioactivity》2009,100(12):1079-1085
Motivated by the detection of 131I in river sediment in routine long-term surveillance samples, a systematic short-term study of the wastewater treatment chain was planned and conducted. Inflow, effluent and primary sludge were collected on a daily basis during two weeks at a regional wastewater treatment plant. Samples were investigated by gamma spectroscopy. Four medically used isotopes could be identified (131I and 99mTc regularly, 153Sm and 123I sporadically). The concentration levels coincide well with literature data for 131I, and with our own long-term data for 131I and 99mTc for the same plant. Cosmogenic 7Be activity in primary sludge correlated well with rainfall intensity. Surface sediment was sampled at low tide at both shores of the river, up- and downstream of the plant. 131I was identified in all samples, with a sharp maximum (about 100 Bq kg−1 d.m.) at the discharge point of the plant and lower levels elsewhere, decreasing monotonically in downstream direction. 7Be and 137Cs showed the same behaviour, but no peak at the discharge point. Predictions from simple equilibrium models for the transport and sedimentation of 131I show good agreement with the experimental data and suggest that the wastewater treatment plant is the main source for this isotope. 相似文献
213.
Sylwia Wojas Sonia Plaza Oskar Siemianowski Anna Ruszczyńska Danuta M. Antosiewicz 《Environmental pollution (Barking, Essex : 1987)》2009,157(10):2781-2789
Arabidopsis MRPs/ABCCs have been shown to remove various organic and inorganic substrates from the cytosol to other subcellular compartments. Here we first demonstrate that heterologous expression of AtMRP7 in tobacco (Nicotiana tabacum var. Xanthi) modifies cadmium accumulation, distribution and tolerance. Arabidopsis MRP7 was localized both in the tonoplast and in the plasma membrane when expressed in tobacco. Its overexpression increased tobacco Cd-tolerance and resulted in enhanced cadmium concentration in leaf vacuoles, indicating more efficient detoxification by means of vacuolar storage. Heterologous AtMRP7 expression also led to more efficient retention of Cd in roots, suggesting a contribution to the control of cadmium root-to-shoot translocation. The results underscore the use of AtMRP7 in plant genetic engineering to modify the heavy-metal accumulation pattern for a broad range of applications. 相似文献
214.
等离子喷涂法制备了钛基亚氧化钛电极(Ti/Ti_4O_7),以该电极为阳极,研究了电化学氧化法对水中美托洛尔的去除效果.考察了电流密度(5~25 mA·cm~(-2))、极板间距(5~25 mm)和初始浓度(3~50 mg·L~(-1))对美托洛尔电化学降解效率的影响;分析美托洛尔电化学降解过程中溶液总有机碳(TOC)和毒性的变化,鉴别反应中间产物并计算其毒性.研究表明:Ti/Ti_4O_7阳极电化学降解美托洛尔反应符合一级反应动力学规律(R20.95),降解效率随电流密度的增大而增大,随极板间距和初始浓度的增大而减小;TOC去除率在反应40 min后可达56.5%;反应过程中产生了质合比为266、250、223和207的中间产物,造成美托洛尔溶液的生物毒性在电化学反应过程中先升高后下降. 相似文献
215.
以野外收集的水华蓝藻为原料,经过75%甲醇溶液浸提,快速色谱分离和半制备色谱纯化,从滇池水华蓝藻中分离纯化出1种微囊藻毒素变体。电喷雾质谱、紫外分光光度计和HPLC检测结果表明,所得毒素为[Dha7]MCRR,是MCRR的1种去甲基化变体,其纯度大于 95%。该毒素的分子组成为环(Ala-Arg-MeAsp-Arg-Adda-Glu-Dha),分子量为1023,其紫外扫描光谱(200~300nm)在239nm处有特征吸收。[Dha7]MCRR在滇池水华蓝藻中普遍存在,有时会成为MC的主要种类。 相似文献
216.
Choi JW Lee W Lee DB Park CH Kim JS Jang YH Kim Y 《Environmental monitoring and assessment》2007,129(1-3):37-42
The immobilized cell using self-assembled synthetic oligopeptide was applied to the electrochemical detection of pathogen
infection. Thin films based on cysteine-terminated synthetic oligopeptides were fabricated for the immobilization of HeLa
cell on gold (Au) substrate. Layer formation and immobilization of the cell were investigated with surface plasmon resonance
(SPR) and electrochemical impedance spectroscopy (EIS). Experimental results showed that the thin film of cysteine-terminated
synthetic oligopeptide was successfully fabricated and it could be applied for the immobilization of HeLa cells. The adhered
living cell was exposed to E. coli O157:H7, which induced the change of SPR angle and electrochemical impedance signal. The proposed cell immobilization method
using self-assembly technique can be applied to construct the cell microarray for on-site pathogen monitoring. 相似文献
217.
218.
目的研究氧化物TiO_2 B位掺杂对Sm_2Zr2O_7陶瓷材料的结构及热物理性能的影响。方法以Sm_2O_3、ZrO_2、TiO_2为原料,通过高温固相合成法制备用过渡金属氧化物TiO_2掺杂Sm_2Zr2O_7的Sm_2(Zr_(1-x)Ti_x)_2O_7(x=0,0.2,0.4,x为摩尔分数)陶瓷材料。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)研究陶瓷材料的物相结构以及显微形貌,利用阿基米德原理测定陶瓷材料的体积密度。根据Neumann-Kopp定律计算材料热容,采用高温热膨胀仪及激光导热仪对材料的热膨胀性能和热导率进行表征。结果 Sm_2(Zr_(1-x)Ti_x)_2O_7体系陶瓷材料为立方烧绿石结构,显微结构致密,晶界清晰。Sm_2Zr2O_7掺杂小离子半径Ti~(4+)使其热膨胀系数有所提高,热扩散系数降低,并在高温下表现出类似于玻璃的超低热导率。800℃时,Sm_2Zr_(1.6)Ti_(0.4)O_7的热导率为1.29 W/(m·K),平均热膨胀系数达到10.6×10~(-6) K~(-1)。结论由于基质原子与取代原子之间的原子量差随Ti掺杂量的增加而逐渐降低,其热导率随Ti掺杂量增加而升高。 相似文献
219.
L andsat-7 SLC- OFF ETM遥感数据下载及在太湖蓝藻水华监测中的应用 总被引:4,自引:1,他引:4
李旭文 《环境监测管理与技术》2009,21(3):54-57
利用互联网上USGS提供的公益性Landsat-7SLC—OFFETM遥感数据下载服务,建立了太湖地区2003年-2008年ETM遥感影像数据库,开展蓝藻水华面积解译和暴发特征分析。统计结果表明,2007年和2008年太湖蓝藻水华暴发呈加剧态势。 相似文献
220.
Alexandra L. DeCandia Andrew P. Dobson Bridgett M. vonHoldt 《Conservation biology》2018,32(4):798-807
Pathogens pose serious threats to human health, agricultural investment, and biodiversity conservation through the emergence of zoonoses, spillover to domestic livestock, and epizootic outbreaks. As such, wildlife managers are often tasked with mitigating the negative effects of disease. Yet, parasites form a major component of biodiversity that often persist. This is due to logistical challenges of implementing management strategies and to insufficient understanding of host–parasite dynamics. We advocate for an inclusive understanding of molecular diversity in driving parasite infection and variable host disease states in wildlife systems. More specifically, we examine the roles of genetic, epigenetic, and commensal microbial variation in disease pathogenesis. These include mechanisms underlying parasite virulence and host resistance and tolerance, and the development, regulation, and parasite subversion of immune pathways, among other processes. Case studies of devil facial tumor disease in Tasmanian devils (Sarcophilus harrisii) and chytridiomycosis in globally distributed amphibians exemplify the broad range of questions that can be addressed by examining different facets of molecular diversity. For particularly complex systems, integrative molecular analyses present a promising frontier that can provide critical insights necessary to elucidate disease dynamics operating across scales. These insights enable more accurate risk assessment, reconstruction of transmission pathways, discernment of optimal intervention strategies, and development of more effective and ecologically sound treatments that minimize damage to the host population and environment. Such measures are crucial when mitigating threats posed by wildlife disease to humans, domestic animals, and species of conservation concern. 相似文献