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221.
Popularity of herbal drugs is increasing all over the world because of lesser side effects as compared to synthetic drugs. Besides, it costs less and easily available to poor people particularly in developing countries. But quality assurance of herbal drugs is very necessary prior to its use. Because in today's polluted environment, even herbal drugs are not safe. Berberis spp. is very important medicinal plant, having various medicinal properties. It is also included in Indian and British pharmacopoeias. Its demand is quite high in herbal drug market. So, to check the quality of market samples of this drug, ten different samples were procured from different drug markets of India for heavy metal estimation. Besides, genuine samples of four species of Berberis viz. B. aristata, B. chitria, B. lycium, B. asiatica were also collected from natural habitats to compare heavy metal concentration in both market and genuine samples. It was found that market samples were much more contaminated than genuine samples. Lead (Pb) concentration is far beyond from WHO permissible limit (10 ppm) for herbal drugs, reaching to maximum 49.75 ppm in Amritsar market sample. Likewise, concentration of all other metals like Cd, Cr and Ni were also very high in market samples as compared to genuine samples.  相似文献   
222.
Under the Clean Air Act Amendments of 1990, the U.S. Environmental Protection Agency (EPA) determined that regulation of mercury emissions from coal-fired power plants is appropriate and necessary. To aid in this determination, preliminary estimates of the performance and cost of powdered activated carbon (PAC) injection-based mercury control technologies were developed. This paper presents these estimates and develops projections of costs for future applications. Cost estimates were developed using PAC to achieve a minimum of 80% mercury removal at plants using electrostatic precipitators and a minimum of 90% removal at plants using fabric filters. These estimates ranged from 0.305 to 3.783 mills/kWh. However, the higher costs were associated with a minority of plants using hot-side electrostatic precipitators (HESPs). If these costs are excluded, the estimates range from 0.305 to 1.915 mills/kWh. Cost projections developed using a composite lime-PAC sorbent for mercury removal ranged from 0.183 to 2.270 mills/kWh, with the higher costs being associated with a minority of plants that used HESPs.  相似文献   
223.
S.K. Tandon  Laj Srivastava 《Chemosphere》1985,14(10):1579-1587
The ability of selective polyaminocarboxylic acids and common drugs to reduce the body burden of chromium and restore Cr induced biochemical alterations in chromate intoxicated rats was investigated. 1,2 Cyclohexylene dinitrilotetraacetic acid (CDTA) and triethylenetetramine hexacetic acid (TTHA) were more effective than p-aminosalicylic acid (PAS) and isoniazid (INH) in enhancing urinary excretion of Cr, lowering hepatic and blood levels of Cr and restoring inhibited activity of hepatic aldolase. The chromate antidotal property of chelators seem to be related to the combination of nitrogen and oxygen as the electron donating centres.  相似文献   
224.
Using data from 23 populations of Indian langurs (Presbytis entellus), we show that the proportion of one-male groups is a function of the males’ ability to defend groups of females, as predicted by the monopolisation model of Emlen and Oring (1977). However, we show that in addition to the number of females in the group and their reproductive synchrony, home range size is also a factor, probably because it affects a male’s willingness to search for other groups. These variables in turn are shown to be functions of environmental parameters (rainfall volume and seasonality, and mean ambient temperature) which probably act via the density of resources and refuges in habitats. Received: 3 March 1994 / Accepted after revision: 24 June 1996  相似文献   
225.
Six film samples of low-density polypropylene (LDPE)/linear LDPE (LLDPE)/high-density polypropylene (HDPE) with varying ratios of LDPE (20–45 ... wt%) and LLDPE (25–50 wt%) having a fixed amount of HDPE at 30 wt% were prepared by blown film extrusion technique. The samples were aged at four different temperatures, 55°, 70°, 85°, and 100°C, for four different time periods in the interval of between 150 hours and up to 600 hours. The change in the structure of various constituents and the formation of various oxygenated (peroxy and hydroperoxy) and unsaturated groups during thermo-oxidative degradation was discussed by infrared spectroscopy. The visiosity-average molecular weight was found to have decreased slowly in the initial aging hours and temperatures, whereas it decreased by 10% with its previous value tensile strength that is, 100°C when aged for 600 hours. The tensile strength of the sample first increased by 67% at 55°C and 89% at 70°C up to 450 hours, whereas the values increased by 52.5% at 85°C and 33.9% at 100°C when aged for 150 hours and then decreased. The percentage elongation at break increased by 2.7% at 55°C and 10.7% at 70°C for 150 and 300 hours of aging, respectively, whereas the percentage decreased when aged at 85°C and 100°C for up to 600 hours of aging. The values of gel content (percent) increased and initial degradation temperature decreased with aging time and temperature.  相似文献   
226.
Adult male deer mice were exposed every other day for a period of 11 days to either 7,12-dimethylbenzanthracene (DMBA; CAS# 57-97-6) or benzo[b]fluoranthene (BbF; CAS# 205-99-2) (0, 0.3, 1, 3, 10, or 30?mg?kg?1). Immune endpoints assessed were lymphocyte proliferation, macrophage pinocytosis, and the antibody plaque-forming cell (PFC) response. Cytochrome P450 (CYP450) activity was assessed using ethoxyresorufin-O-deethylase (EROD) and pentoxyresorufin-O-deethylase (PROD). Macrophage pinocytosis was not altered by either compound. Both T- and B-cell proliferations were significantly increased by DMBA at 0.3 or 1?mg?kg?1 and by BbF at 10 or 30?mg?kg?1, but decreased by DMBA at 30?mg?kg?1. Sheep red blood cell (SRBC)-specific-IgM production, as measured by the PFC response, was the most striking adverse immune effect observed and was significantly suppressed compared to control at all treatment concentrations for both compounds. EROD activity was markedly induced by DMBA at 30?mg?kg?1, while BbF produced induction at 1, 10, or 30?mg?kg?1. No marked effect on PROD activity was noted following DMBA treatment, but BbF-induced PROD activity at 1, 10, or 30?mg?kg?1. Unexpectedly, four of six mice in the 30?mg DMBA?kg?1 group did not survive to the end of the experiment, and one animal died in both the 3 and 10?mg?kg?1 treatments. The calculated LD50 was 20.8?mg DMBA?kg?1. The PFC response in deer mice was a more sensitive endpoint than CYP450 activity, suggesting that utilization of CYP450 endpoints in risk assessment without assessment of immune function, specifically antibody production, might possibly underestimate the risk to wild rodents environmentally exposed to polycyclic aromatic hydrocarbons.  相似文献   
227.
Environmental Chemistry Letters - Microbial fuel cells are used as an alternative source of energy and for microbial degradation of waste and pollutants. Different types of microbial fuel cells...  相似文献   
228.
Phytoextraction is an emerging cost-effective solution for remediation of contaminated soils which involves the removal of toxins, especially heavy metals and metalloids, by the roots of the plants with subsequent transport to aerial plant organs. The aim of the present investigation is to study the effects of EDTA and citric acid on accumulation potential of marigold (Tagetes erecta) to Zn, Cu, Pb, and Cd and also to evaluate the impacts of these chelators (EDTA and citric acid) in combination with all the four heavy metals on the growth of marigold. The plants were grown in pots and treated with Zn (7.3 mg l(-1)), Cu (7.5 mg I(-1)), Pb (3.7 mg l(-1)) and Cd (0.2 mg l(-1)) alone and in combination with different doses of EDTA i.e., 10, 20 and 30 mg l(-1). All the three doses of EDTA i.e., 10, 20 and 30 mg l(-1) significantly increased the accumulation of Zn, Cu, Pb and Cd by roots, stems and leaves as compared to control treatments. The 30 mg l(-1) concentration of citric acid showed reduced accumulation of these metals by root, stem and leaves as compared to lower doses i.e., 10 and 20 mg l(-1). Among the four heavy metals, Zn accumulated in the great amount (526.34 mg kg(-1) DW) followed by Cu (443.14 mg kg(-1) DW), Pb (393.16 mg kg(-1) DW) and Cd (333.62 mg kg(-1) DW) in leaves with 30 mg l(-1) EDTA treatment. The highest concentration of EDTA and citric acid (30 mg l(-1)) caused significant reduction in growth of marigold in terms of plant height, fresh weight of plant, total chlorophyll, carbohydrate content and protein content. Thus EDTA and citric acid efficiently increased the phytoextractability of marigold which can be used to remediate the soil contaminated with these metals.  相似文献   
229.
What are the local community consequences of changes in regional species richness and composition? To answer this question we followed the assembly of microarthropod communities in defaunated areas of moss, embedded in a larger moss "region." Regions were created by combining moss from spatially distinct sites, resulting in regional species pools that differed in both microarthropod richness and composition, but not area. Regional effects were less important than seasonality for local richness. Initial differences in regional richness had no direct effect on local species richness at any time along a successional gradient of 0.5-16 months. The structure of the regional pool affected both local richness and local composition, but these effects were seasonally dependent. Local species richness differed substantially between dates along the successional gradient and continued to increase 16 months after assembly began. To the best of our knowledge, this is the first critical test of saturation theory that experimentally manipulates regional richness. Further, our results failed to support the most important mechanisms proposed to explain the local richness-regional richness relationship. The results demonstrate that complicated interactions between assembly time, seasonality, and regional species pools contribute to structuring local species richness and composition in this community.  相似文献   
230.
Duckweed (Lemna minor) a small vascular plant, grows rapidly, is sensitive to a wide variety of toxicants and is easy to culture. A method is described that measures duckweed frond growth, chlorophyll, protein and biomass content as indicator of growth inhibition. The physico-chemical analysis of anaerobically treated distillery effluent revealed high BOD (28,000 mg/l), COD (52,400 mg/l) and dark brown colour (180,000 Co. Pt.). This effluent showed high toxicity to Lemna minor after 96 h of exposure in laboratory condition. EC50 of the fronds for chlorophyll, protein and biomass was found to be 25%, however, the bacterial decolourised effluent showed reduction of BOD (87.50%), COD (84.50%) and colour (76%). Further the toxicity evaluation with Lemna minor showed toxicity reduction up to 63% for all tested parameters. The EC50 noted for chlorophyll, protein and biomass was 100% concentration of decolourised effluent.  相似文献   
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