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41.
Inna P. Solyanikova Andrej L. Mulyukin Natalja E. Suzina Galina I. El-Registan Ludmila A. Golovleva 《Journal of environmental science and health. Part. B》2013,48(7):638-647
The goals of the present work were as follows: to obtain the dormant forms of R. opacus 1cp; to study the phenotypic variability during their germination; to compare phenotypic variants during the growth on selective and elective media; and to reveal changes in the ability of the strain to destruct xenobiotics that had not been degradable before dormancy. It was shown that Rhodococcus opacus 1cp (the strain degrading chlorinated phenols) became able to utilize a broader spectrum of xenobiotics after storage in the dormant state. Germination of the dormant forms of R. opacus 1cp on an agarized medium was followed by emergence and development of phenotypic variants that could grow on 4-chlorophenol and 2,4,6-trichlorophenol without adaptation. The cells of R. opacus 1cp phenotypic variants also utilized all of the tested chlorinated phenols: 2,3-, 2,5-, and 2,6-dichloro-, 2,3,4- and 2,4,5-trichloro-, pentachlorophenol, and 1,2,4,5-tetrachlorobenzene in concentrations up to 60 mg/L, though at the lower rates than 4-CP and 2,4,6-TCP. The improved degradation of chlorinated phenols by R. opacus strain 1cp exposed to the growth arrest conditions demonstrates the significance of dormancy for further manifestation of the adaptive potential of populations. A new principle of selection of variants with improved biodegradative properties was proposed. It embraces introduction of the dormancy stage into the cell life cycle with subsequent direct inoculation of morphologically different colonies into the media with different toxicants, including those previously not degraded by the strain. 相似文献
42.
GEORGE F. ANTONIOUS TEJINDER S. KOCHHAR ROBERT L. JARRET JOHN C. SNYDER 《Journal of environmental science and health. Part. B》2013,48(7):1237-1243
The U.S. Department of Agriculture (USDA) pepper (Capsicum spp.) germplasm collection contains several thousand members or accessions. Many of these species and cultivars have not been analyzed for their concentrations of ascorbic acid, capsaicin, and total phenolic compounds, which are important antioxidants having a number of benefits for human health. The objective of this investigation was to select candidate accessions of hot pepper having high concentrations of ascorbic acid, capsaicin, free sugars, and total phenols for use as parents in breeding for these compounds. Seventeen accessions of pepper from the core Capsicum germplasm collection (four accessions of Capsicum chinense; five accessions of C. baccatum; six accessions of C. annuum; and two of C. frutescens) were field grown and their mature fruits were analyzed for their antioxidant composition. Concentrations of these compounds tended to be higher in C. chinense and C. baccatum, than in C. annuum and C. frutescens. Across all accessions the concentration of total phenols was correlated with ascorbic acid (r = 0.97) and free sugars (r = 0.80). Concentrations of total phenols (1.4, 1.3, and 1.3 mg g?1 fruit) and ascorbic acid (1.6, 1.2, and 1.3 mg g?1 fruit) were significantly greater in PI-633757, PI-387833, and PI-633754, respectively, compared to other accessions analyzed. Total capsaicinoids concentrations were greatest (1.3 mg g?1 fruit) in PI-438622 and lowest (0.002 mg g?1 fruit) in Grif-9320. The great variability within and among Capsicum species for these phytochemicals suggests that these selected accessions may be useful as parents in hybridization programs to produce fruits with value-added traits. 相似文献
43.
George F. Antonious Lauren Lobel Tejinder Kochhar Terry Berke Robert L. Jarret 《Journal of environmental science and health. Part. B》2013,48(6):621-626
The main objective of this investigation was to evaluate fruits of C. chinense accessions for their concentration of β -carotene, ascorbic acid, and phenols for use as parents in breeding for these phytochemicals. Mature fruits of 63 accessions of C. chinense originally acquired from Belize, Brazil, Colombia, Ecuador, Mexico, Peru, Puerto Rico, and the United States were analyzed for their chemical composition. Fruits of C. chinense accessions PI-152452 (Brazil) and PI-360726 (Ecuador) contained the greatest concentrations of ascorbic acid (1.2 and 1.1 mg g?1 fresh fruit, respectively), while PI-438648 (Mexico) contained the greatest concentration of total phenols content (349 μ g g?1 fresh fruit) among the other 63 accessions tested. Accession PI-355817 from Ecuador contained the greatest concentrations of β -carotene (8 mg g?1fresh fruit). These accessions were identified as potential candidates for mass production of antioxidants with health-promoting properties. 相似文献
44.
The atmosphere is a particularly difficult analytical system because of the very low levels of substances to be analysed,
sharp variations in pollutant levels with time and location, differences in wind, temperature and humidity. This makes the
selection of an efficient sampling technique for air analysis a key step to reliable results. Generally, methods for volatile
organic compounds sampling include collection of the whole air or preconcentration of samples on adsorbents. All the methods
vary from each other according to the sampling technique, type of sorbent, method of extraction and identification technique.
In this review paper we discuss various important aspects for sampling of volatile organic compounds by the widely used and
advanced sampling methods. Characteristics of various adsorbents used for VOCs sampling are also described. Furthermore, this
paper makes an effort to comprehensively review the concentration levels of volatile organic compounds along with the methodology
used for analysis, in major cities of the world. 相似文献
45.
Mingming Lu Prabhat Lamichhane Fuyan Liang Eric Imerman Ming Chai 《Water, Air, & Soil Pollution: Focus》2008,8(3-4):359-367
The odorous air emissions from confined animal feeding operations (CAFOs), such as swine, poultry and dairy farms, are increasingly
raising community complaints. Odorous emissions can result in health damages, psychological discomforts and adverse aesthetic
effects in the community. However, these emissions are not well characterized up to now due to the lack of legislation, the
limitations in sampling and instrumentation techniques, and the complexity of the emissions themselves. This study is aimed
at the development of a high volume sampler and sorbent assembly to identify the odor causing compounds from a diary CAFO.
The sorbent was custom designed to target the potential compounds that may exist in a dairy farm and was validated in laboratory
with a synthetic odor from the swine manure. The actual samples at the diary farm were collected in spring and summer of 2005.
The sorbents were solvent extracted and individual odor compounds were identified using GC–MS (gas chromatography–mass spectroscopy).
The data obtained indicated that high volume sampling can shorten the sampling time from days to within 4 h. Both volatile
organic compounds (VOCs) and volatile fatty acids (VFAs) have been identified from the dairy farm, such as phenol, methylphenol,
4-ethyl phenol, indole, methyl indole, benzyl alcohol, hexanoic acid, valeric acid and iso-valeric acid, together with some nitrogen containing compounds that have not been reported before. 相似文献
46.
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48.
Aluminum powder was always chosen as an additive to improve the explosive performance. In this work, experiments were performed to investigate the lower flammability limit (LFL) of volatile liquid fuel-aluminum powder mixtures using a 20 L closed spherical stainless steel vessel at a temperature of 20 °C (293 K) and 40 °C (313 K). The volatile liquid fuels tested in the work were diethyl ether (DEE), epoxypropane (PO), n-pentane and n-hexane. DEE, PO and n-pentane are in the liquid phase at room temperature and can easily transition to the gas phase at 40 °C (313 K). Through a series of experiments carried out, it was found that the change in phase would affect the interaction between the components. Aluminum powder always has an inhibitory effect on the flammability of the mixtures when it is mixed with gas-phase fuels. The inhibition effect was most obvious when the aluminum powder concentration reached 200 g/m3. While the interaction between aluminum powder and liquid-phase volatile fuels was promotion and was influenced by the component proportion and the type of the volatile fuels. 相似文献
49.
本文通过查阅文献资料,总结了当前企业挥发性有机废气产生情况、政策管理办法以及相关处理技术,并分析了未来挥发性有机废气治理政策发展趋势,旨在提高挥发性有机废气治理效率,提高空气环境质量。 相似文献
50.
以质量比9∶1的活性炭和乙炔黑制备气体扩散电极,着重研究电流密度、pH值、曝气量等因素对H2O2产生量的影响.结果表明:pH值在较大范围内均适用;电流密度控制在50~75 mA/cm2,曝气量确定为5 L/min时,反应产生H2O2较多.另外,利用该气体扩散电极做阴极,石墨电极做阳极,以Na2SO4为电解质,研究了电解时间、电流密度、pH值、初始苯酚浓度、曝气量等因素对苯酚降解效果的影响.结果表明:在电流密度为75 mA/cm2、曝气量为5 L/min、初始pH=3的条件下,当苯酚的初始浓度为80 mg/L时,1 h后其去除率达77%. 相似文献