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排序方式: 共有245条查询结果,搜索用时 31 毫秒
61.
Kathleen E. Duncan Ravindra Kolhatkar Ganesh Subramaniam Ramesh Narasimhan Eleanor Jennings Susan Hettenbach Amanda Brown Charles McComas William Potter Kerry Sublette 《Applied biochemistry and biotechnology》1999,78(1-3):421-434
A remote site in the Tallgrass Prairie Preserve (Osage County, OK) was contaminated with crude oil by a pipeline break in
1992. In 1996, the contaminated soil was bioremediated by blending with uncontaminated soil, prairie hay, buffalo manure,
and commercial fertilizers, and spreading in a shallow layer over uncontaminated soil to create a landfarm. The landfarm was
monitored for two years for aerobic and anaerobic bacteria, soil gases indicative of microbial activity, and for changes in
the concentration of total petroleum hydrocarbons (TPH). Levels of hydrocarbon degraders and soil gas indicators of aerobic
degradation were stimulated in the landfarm during the first warm season relative to uncontaminated prairie soil. However,
these same indicators were less conclusive during the second warm season, indicating depletion of the more easily degradable
hydrocarbons, although the landfarm still contained 6,800 mg/kg TPH on the average at the beginning of the second warm season.
Methane formation and methanogen counts were clearly stimulated in the first warm season relative to uncontaminated prairie
soil, in dicating that methanogenesis plays an important role in the mineralization of hydrocarbons even in these shallow
soils. 相似文献
62.
63.
Subramaniam Ramdas William Jones John M. Thomas Jean-Pierre Desvergne 《Chemical physics letters》1978,57(3):468-470
The photodimerization of 1,5-dichloroanthracene is discussed with particular reference to the mechanism by which the ratio of head-to-head and head-to-tail dimer differs between reaction in the solid and in solution. It is shown that in certain crystallographic space groups linear and planar imperfections will not, of themselves, produce regions of packing suitable for the formation of the “non-topochemical” dimer. A novel type of point defect which may account for the solid state reactivity is described and the extra lattice energy that is associated with this defect calculated. 相似文献
64.
J P Landers M D Schuchard M Subramaniam T P Sismelich T C Spelsberg 《Journal of chromatography. A》1992,603(1-2):247-257
This study highlights the potential utility of high-performance capillary electrophoresis (HPCE) for monitoring enzyme activity. Free-zone capillary electrophoresis is used to rapidly and reproducibly analyze the activity of the bacterial enzyme chloramphenicol acetyl transferase (CAT) which converts the substrates acetyl coenzyme A (CoA) and chloramphenicol to acetyl chloramphenicol and CoA. The results of this study indicate that HPCE may be an excellent tool for studying enzyme activities since it has several advantages over standard single parameters assays, most notably, the ability to monitor both loss of substrate and appearance of products simultaneously. Conditions have been identified for optimal separation of the substrate (chloramphenicol) from the products (acetylated derivatives). This presents a unique potential of HPCE for the analysis of enzymatic reactions that may be applied to areas of analytical research presently utilizing enzymatic reactions. One such analytical method is the CAT assay used for analysis of gene promoter activity. In this study, HPCE is shown to yield similar quantitative results with nonradiolabelled substrate in a fraction of the time. HPCE has several advantages over standard techniques including speed of analysis, no need for radiolabelled substrate, small sample volumes, high sensitivity/resolution and excellent quantitative capabilities. 相似文献
65.
66.
The visible absorption spectrum of thiocarbonyl chlorofluoride, ClFCS, in the region 5000 to 3000 Å has been observed under conditions of high resolution in the vapor phase and has been assigned to the and electronic transitions. All six fundamental modes have been assigned for both the upper and lower singlet electronic states. From the observed splittings of the even-odd quanta of ν6′ in the spectrum the barrier to inversion in the state has been evaluated to be 1556.0 ± 45 cm?1. 相似文献
67.
This paper deals with a theoretical investigation of the energy spectrum of thermal neutrons inelastically scattered by a ferromagnetic crystal. The method of double-time temperature-dependent Green’s functions is used. Formulæ are derived for the line width and for an asymmetry parameter leading to a deviation from the Lorentzian form. The results are discussed and compar d with earlier work. Special attention is paid to the question of the deviation of the energy distribution from the purely Lorentzian form. 相似文献
68.
2′,5,6,7-Tetramethoxyflavone, synthesized by two methods has been found to be different from zapotin. 相似文献
69.
70.
Tarak Nath Burai Debashis Panda E Siva Subramaniam Iyer Anindya Datta 《Journal of luminescence》2012,132(11):2929-2936
The rate and extent of photoinduced electron transfer change significantly as a result of confinement in nanovolumes. Study of such processes is an active area of research in physical chemistry. The effect is most interesting when the molecules that participate in PET are charged. In the present article, the modulation of PET has been studied for two anionic fluorophores: Lucifer Yellow CH and chlorin p6 with Methylviologen dication. PET, manifested in the quenching of fluorescence of the fluorophores, has been modulated by incorporating the molecules in organized assemblies like micelles, reverse micelles and supramolecular hosts. The dynamics of the process has been monitored in the femtosecond to nanosecond timescale. The modulation of the electron transfer has been found to be occurring mainly due to the disruption of contact ion pairs formed between the fluorophores and the quencher. 相似文献