نتایج جستجو برای: polycyclic
تعداد نتایج: 12913 فیلتر نتایج به سال:
The quality of wide a variety of synthetic or naturally occurring materials which are used for outdoor applications are known to be adversely affected by environmental factors. These materials absorb solar ultraviolet radiation leading to changes in their structures and compositions. The consequences of these changes lead to degradation of the materials. Bitumen is one of the materials which is...
The mutagenic activity of the polycyclic aromatic hydrocar bon-containing fraction of several soot samples was measured in Salmonella typhimurium, using resistance to the purine analog 8-azaguanine as a genetic marker. A postmitochondrial supernatant derived from livers of phénobarbitaland/or Aroclor-pretreated male Sprague-Dawley rats was incorporated into all assays to allow metabolism of pr...
Other investigators have shown that several polycyclic carcinogens are frameshift mutagens in Salmonella. Mutagenic potency of these compounds is assessed by ability to induce reversion of histidine-requiring frameshift mutants to prototrophy. One frameshift mutation in the histidinol dehydrogenase gene, hisD3052, is unusually sensitive to mutagenesis by certain polycyclic carcinogens. We find ...
The separation of chiral compounds is an interesting and challenging topic in analytical chemistry, especially in environmental fields. Enantioselective degradation or bioaccumulation has been observed for several chiral pollutants. Polycyclic musks are chiral and are widely used as fragrances in a variety of personal care products such as soaps, shampoos, cosmetics and perfumes. In this study,...
Narrow temperature range distillates from biologically active solvent refined coal-I and -II heavy-end coal liquids were fractionated according to chemical class and assayed for initiation of skin carcinogenesis in CD-1 mice. In addition, instrumental chemical analyses were performed on the distillates and their chemical fractions. Results showed that initiation activity in these complex fuel m...
OBJECTIVE To develop a strategy for water quality monitoring for the presence of genotoxins and polycyclic aromatic hydrocarbons. METHODS A study was carried out in Santos estuary, Southern Brazil, in 2002. Two sampling sites with different concentration levels were selected and evaluated in different samplings using blue rayon hanging technique, chemical analyses, and Salmonella/microsome as...
Hopanes and steranes are found almost universally in the sedimentary rock record where they often are used as proxies for aerobic organisms, metabolisms, and environments. In order to interpret ancient lipid signatures confidently we require a complementary understanding of how these modern biochemical pathways evolved since their conception. For example, generally it has been assumed that hopa...
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