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A toxicological evaluation was conducted on wetland habitats created as a result of run-off from agricultural areas. These temporary wetlands were created by using drop pipes as a means of reducing erosional cutting in agricultural fields. Toxicity bioassays utilizing bacterial bioluminescence and Hyalella azteca were used to assess sediment pore water and whole sediment, respectively. Inhibition of bacterial bioluminescence was initially used to determine relative toxicities of pore water from ten wetland sites. Constructed wetland sites were compared to the University of Mississippi Biological Field Station, a relatively pristine reference site. The H. azteca ten day sediment toxicity test was utilized to assess sediment from four selected sites using survival and growth as toxicological endpoints. Results from the toxicological evaluation, along with extensive ecological evaluations, were used to assess the best approach for implementation of temporary wetland habitats with existing agricultural practices.  相似文献   

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李颖  倪文  陈德平  王中杰  张斌 《工程科学学报》2012,34(11):1308-1313
通过正交试验研究了用作制备高强度人工鱼礁的钢渣-矿渣-熟料-石膏体系胶凝材料的强度.净浆正交试验表明:钢渣:矿渣的复合比为5:3,并与10%的水泥熟料和10%的脱硫石膏复合的胶凝材料具有较高的强度.以优化后的胶凝材料代替水泥,并以热闷法稳定化的钢渣颗粒为骨料,可以制备出抗压强度达到50 MPa以上的人工鱼礁混凝土.利用X射线衍射和扫描电镜分析净浆的水化过程,发现体系在早期水化主要生成AFt相和C-S-H凝胶,在后期钢渣和矿渣的火山灰活性反应对强度的增长起主要作用.  相似文献   

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The antitumour activity of peritoneal macrophages, added to tumour inocula (Winn test), was determined. Macrophages harvested from mice immunised with tumour, or from tumour-bearing mice, suppressed or inhibited tumour growth when in direct contact with tumour cells. Incubation of macrophages exhibiting antitumour activity with tumour cells yielded supernatant fluids capable of interfering with tumour growth. Consistent induction of antitumor activity required either addition of indomethacin to the incubation mixture, or collection of macrophages from immunised or tumour-bearing donors that had ingested indomethacin in the drinking water. Tumour growth was significantly inhibited when tumour inocula were suspended in supernatant fluid, or when mice were given several subcutaneous injections of supernatant prior to tumour transplantation.  相似文献   

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Summary On the basis of the biological activity of various elements in Mendeleev's periodic system and their electronic structure, the authors determined a correlation which points to a decrease in toxicity of elements which increase in statistical weight of stable electronic configurations. Nonmetal and semimetal toxicity increases with an increase in the principal quantum number while the biological activity of transition metals decreases. The results obtained can be used for hygienic estimation of the biological action of inorganic substances.Printed as a discussion.Translated from Poroshkovaya Metallurgiya, No. 9(45), pp. 101–109, September, 1966.  相似文献   

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Cluster headache is a brutal affliction characterized by excruciating pain with relatively brief, but frequent attacks. Because of the short duration of the attacks and the tremendous intensity of pain, symptomatic analgesics are often not effective. However, inhalation oxygen, while being cumbersome, is reported to be effective in the majority of sufferers. To assess the practical effectiveness and use of analgesics and/or oxygen, a review of 60 cluster patients was conducted. At initial evaluation, 48 patients had accepted oral analgesics and 51 patients accepted inhalation oxygen for breakthrough headaches. After acceptable prophylactic treatment was established, 65% of patients who accepted analgesics continued their use, although most reported only minimal relief. Only 31% of patients who accepted oxygen continued its use, in spite of the fact that most sufferers reported significant relief. From this brief study, it appears that cluster headache patients prefer to use analgesics for reasons that are not solely for relief of pain, and that patients decline the use of oxygen for reasons other than lack of effectiveness.  相似文献   

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In contrast to the standard use of regression, in which an individual's score on the dependent variable is unknown, neuropsychologists are often interested in comparing a predicted score with a known obtained score. Existing inferential methods use the standard error for a new case (sN+1) to provide confidence limits on a predicted score and hence are tailored to the standard usage. However, sN+1 can be used to test whether the discrepancy between a patient's predicted and obtained scores was drawn from the distribution of discrepancies in a control population. This method simultaneously provides a point estimate of the percentage of the control population that would exhibit a larger discrepancy. A method for obtaining confidence limits on this percentage is also developed. These methods can be used with existing regression equations and are particularly useful when the sample used to generate a regression equation is modest in size. Monte Carlo simulations confirm the validity of the methods, and computer programs that implement them are described and made available. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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简述了济钢信息化建设及产品检化验室的现状,结合国内外实验室管理的发展趋势,设计了钢铁产品质量检验信息化系统的实施方案,阐述了信息化系统的主要功能、作用和应用效果。  相似文献   

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Hypothesized that extraversion scores should correlate with scores on performance tasks purported to depend on cortical inhibition. Data from 104 undergraduates who performed spatial and internal inhibition tasks did not reveal any significant correlations between extraversion (Maudsley Personality Inventory) and performance measures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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Nucleotide sequence of the luzA gene (GenBank accession No. AF039303) from Photobacterium leiognathi ATCC 25521 (NCIMB 2193) has been determined, and the chaperone encoded by the luzA gene was deduced. The LuzA chaperone has a calculated M(r) 26,295 and comprises 230 amino acid residues; the hydrophobic alpha-helix N-terminal 21 amino acid residues MKKTIFALLFMSVFI SYPSFA is the leader peptide, therefore the matured LuzA chaperone has a calculated M(r) 23,871 and comprises 209 amino acid residues only. The periplasmic LuzA chaperone is the protein concerned with the protein folding, assembly and stability. The luzA gene and the related genes are closely linked to the sod gene, that encoding Cu/Zn superoxide dismutase enables to enhance bioluminescence of the lux operon; the gene order of the luzA gene and related genes is -ufo'-luzA-ufoI-ufoII-ter->-R&R'-sod-ufo-- >. In trans complementation bioluminoassays in vivo elicit that the LuzA chaperone might be not directly concerned with bioluminescence of the lux operon from P. leiognathi in E. coli, but might enable to stabilize the proteins related to bioluminescence. The unidentified ufoII gene closely linked to the luzA gene is able to enhance bioluminescence.  相似文献   

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Forces and flow of material in metal working decisively depend on friction between workpiece and tool, which can be described by the friction factor m. For investigation of the influence of friction in hot forming of steel and for measurement of the friction factor, the ring compression test is used as simulation test. The influences of material, reduction, strain rate, temperature, and lubricant are discussed.  相似文献   

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In a field study emissions and immissions (receptor exposition) of bioaerosols emitted from and near a duck fattening house (25 m distance) were investigated. Within the livestock building mean concentrations of 3,342,289 CFU m-3 for airborne total mesophilic bacteria were determined. Total dust and endotoxin yields were 1.9 mg m-3 and 7,132.4 ng m-3, respectively. Additionally, enterobacteria, mesophilic and thermotolerante fungi as well as mesophilic actinomycetes were detectable. Measurements of immissions have shown, that downwind in the rear of the house a mean total germ concentration of 10,007 CFU m-3 was measurable in contrast to the upwind side of the building, where no airborne mesophilic bacteria were found. Higher concentrations downwind were generally determined for total dust, mesophilic fungi and actinomycetes, too, but not so for endotoxins. A supporting application of a numeric dispersion model confirmed the immissions for total mesophilic bacteria near by the duck fattening house. From this viewpoint immission predictions can be made in future for varying input data, i.e. wind conditions, of different components of bioaerosols.  相似文献   

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