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排序方式: 共有595条查询结果,搜索用时 296 毫秒
41.
Huilun Chen Honghao Rao Pengzhen He Yongxiang Qiao Fei Wang Haijun Liu Minmin Cai Jun Yao 《Environmental science and pollution research international》2014,21(19):11340-11348
Antibiotics are widely used in daily life but their abuse has posed a potential threat to human health. To evaluate the toxicity of chloramphenicol (CAP) at the protein level, the interaction between CAP and human serum albumin (HSA) was investigated by fluorescence, Ultraviolet–visible (UV–Vis) absorption, Fourier transform infrared (FT-IR) spectroscopy and molecular docking methods. Fluorescence data revealed that the fluorescence quenching of HSA by CAP was the result of the formation of CAP–HSA complex, and the binding constant was determined to be 3.196?×?104 L mol?1 at 310 K. The thermodynamic determination indicated that the interaction was driven by enthalpy change and entropy change together, where the multiple hydrogen bonds (CAP and the residues Arg 222 and His 242 of HSA) and van der Waals forces were the dominant binding force. The site marker competition revealed that CAP bound into sub-domain IIA of HSA. The binding of CAP induced the drastic reduction in α-helix conformation and the significant enhancement in β-sheet conformation of HSA. Molecular docking study further confirmed the binding mode obtained by experimental study. This work provides a new quantitative evaluation method for antibiotics to cause the protein damage. 相似文献
42.
Rainfall trends in twentieth century over Kerala,India 总被引:1,自引:0,他引:1
K.N. Krishnakumar G.S.L.H.V. Prasada Rao C.S. Gopakumar 《Atmospheric environment (Oxford, England : 1994)》2009,43(11):1940-1944
Attempts were made to study temporal variation in monthly, seasonal and annual rainfall over Kerala, India, during the period from 1871 to 2005. Longterm changes in rainfall determined by Man-Kendall rank statistics and linear trend. The analysis revealed significant decrease in southwest monsoon rainfall while increase in post-monsoon season over the State of Kerala which is popularly known as the “Gateway of summer monsoon”. Rainfall during winter and summer seasons showed insignificant increasing trend. Rainfall during June and July showed significant decreasing trend while increasing trend in January, February and April. Hydel power generation and water availability during summer months are the concern in the State due to rainfall decline in June and July, which are the rainiest months. At the same time, majority of plantation crops are likely to benefit due to increase in rainfall during the post-monsoon season if they are stable and prolonged. 相似文献
43.
G. N. Rao J. N. Beck H. E. Murray D. J. Nyman 《Journal of the American Water Resources Association》1991,27(1):47-58
ABSTRACT: Specific capacity data obtained from Well Construction reports which are available from USGS offices, can provide useful estimates of tranamissivity (T), and hydraulic conductivity (K), of an aquifer. The Chicot Aquifer in Louisiana is one of the largest sources of fresh ground water in North America. Hydrologic data collected for the Chicot Aquifer indicate that specific capacity tests can be used in estimating local and regional values for T and K, if the Cooper-Jacob equation for transient flow is used with proper corrections for well loss and partial penetration. Where full scale pumping test data are scarce, specific capacity test data that are adequately distributed spatially can be used to map changes in T and K values and can be summarized statistically to indicate applicable regional values. A computer program called “TGUESS” which is available from International Ground Water Modeling Center, Holcomb Research Institute, was used in this study. The contour maps for T and K values are prepared for different well depth intervals to avoid wide variation of values. 相似文献
44.
K. Satyanarayana M. Borah P. G. Rao 《Journal of Loss Prevention in the Process Industries》1991,4(5):344-347
Various models of fireball diameter have been evaluated by statistical techniques. The model of Gayle for fireball diameter estimation showed good agreement between the predicted and experimental data. The models relating to fireball duration, transmissivity and view factor have been selected based on their relative merits. A user interactive computer program has been developed to predict thermal hazards from fireballs in chemical process industries. 相似文献
45.
Nageshwar Rao Bhaskar E. Earl Whitlatch 《Journal of the American Water Resources Association》1987,23(6):1027-1036
ABSTRACT: Mathematical optimization techniques are used to study the operation and design of a single, multi-purpose reservoir system. Optimal monthly release policies are derived for Hoover Reservoir, located in Central Ohio, using chance-constrained linear programming and dynamic programming-regression methodologies. Important characteristics of the former approach are derived, discussed, and graphically illustrated using Hoover Reservoir as a case example. Simulation procedures are used to examine and compare the overall performance of the optimal monthly reservoir release policies derived under the two approaches. Results indicate that, for the mean detention time and the corresponding safe yield target water supply release under existing design of Hoover Reservoir, the dynamic programming policies produce lower average annual losses (as defined by a two-sided quadratic loss function) while achieving at least as high reliability levels when compared to policies derived under the chance-constrained linear programming method. In making this comparison, the reservoir release policies, although not identical, are assumed to be linear. This restricted form of the release policy is necessary to make the chance-constrained programming method mathematically tractable. 相似文献
46.
Stephen E. Draper Srinivas G. Rao 《Journal of the American Water Resources Association》1986,22(6):941-949
ABSTRACT: Percent imperviousness is an important parameter in modeling the urban rainfall-runoff process and is usually determined using manual methods such as random sampling or conventional accounting methods. In this study two computerized methods are used for estimating the percent imperviousness of urban watersheds using high altitude remote sensing imagery. These methods include the Laser Image Processing Scanner and the Video-Tape Camera system. Imperviousness is directly estimated in the former method while in the latter it is estimated as a function of the statistics of the responses on emulsions of the imagery. The percent imperviousness computed by utilizing remote sensing imagery was used with the conceptual models of rainfall-runoff models. The models were applied to four urban watersheds and the runoff prediction results indicate that imperviousness determined by using remote sensing imagery was as accurate as that obtained by the manual methods, and that the use of remote sensing imagery requires significantly less time and money. 相似文献
47.
Venkateswara R. Rao 《Environmental management》1995,19(3):313-320
Risk management practices under the current environmental regulations is a long, complex process that considers scientific,
technologic, and management factors to develop various regulatory standards and pollution control measures. Using the mandatory
enforcement approach, sometimes referred to as “command-and-control”, a set of preliminary environmental goals, such as better
air and water qualities, were achieved. However, the information-intensive nature of the risk management process and the lack
of flexibility in conventional regulatory methods to changing economic and technologic realities of the decade has created
interest among risk managers to examine some innovative management approaches. Above all, environmental problems of a global
scale require novel management methods while striving to achieve the desired environmental goals.
As the principal analytical tool in risk management, quantitative risk assessment exerts considerable influence on the risk
management process. Therefore, advances in risk management are closely associated with scientific developments that enhance
the risk assessment process, particularly those efforts aimed at improving human exposure and toxicity assessments. Market
incentives, information dissemination, creative enforcement practices, and interagency and intergovernmental interactions
were identified as the key elements of innovative environmental risk management practices. This paper will present an overview
of the emerging innovative risk management approaches. 相似文献
48.
49.
通过对四川省科技人力资源的潜力、结构变化的分析,提出建立统一规范的科技人才培养经费投入政策,加强科技人才资源的再开发,不拘一格引进科技人才,建立四川省科技人力资源监测系统等对策。 相似文献
50.
Ronald A. Chadderton Robert G. Traver Jayaram N. Rao 《Journal of the American Water Resources Association》1992,28(6):1069-1076
ABSTRACT: This paper presents a study which used a standard, hydraulic computer model to generate detailed design information to support conflict analysis of a water resource use issue. As an extension of previous studies, the conflict analysis in this case included several scenarios for stability analysis - all of which reached the conclusion that compromising, shared access to the water resources available would result in the most benefits to society. This expected equilibrium outcome was found to maximize benefit-cost estimates. 相似文献