摘要:

A two‐phase anaerobic digestion system with a completely mixed acid reactor was studied using a 2 percent synthetic glucose substrate. The steady‐state performance of the acid phase was studied at pH 4.3 and a hydraulic retention time (HRT) of 4.5 hours for 117 days. Separation of phases was noted under these conditions as methane production in acid reactor was initially less than 10 percent of the total gas. The effects of pH and HRT on the acid phase were observed by adjusting pH levels to A.3 and 6.5 and HRT to 2, 4.5 and 8 hours.

ISSN:0360-1226    

DOI:10.1080/10934528509375207

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

In anin vitrostudy, ascorbic acid reduced the occurrence of copper acetate‐induced oxidative stress in human erythrocytes at biologically relevant concentrations (0.06 ‐ 0.25 mM) while enhancing oxidative changes [i.e., changes in methemoglobin (METHB) and reduced glutathione (GSH)] at higher levels of exposure (> 1.0 mM).

ISSN:0360-1226    

DOI:10.1080/10934528509375208

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The growth inhibitions and parallel morphological changes due to three arsenic compounds (sodium arsenite, arsenate, and dimethylarsinate) are examined and compared systematically for the first time in cultured mammalian cells. We used suspension‐adapted Chinese hamster ovary (CHO‐S) cells and cultured them under low and high folate conditions to assess whether arsenic toxicity is related to 1‐carbon metabolism. The concentration of arsenite required to produce a 50% growth rate inhibition is increased from 4 μM to 22 μM when the culture medium folate level is raised from 0.2 μM (low folate) to 2.0 μM (high folate). Arsenate is less inhibitory than arsenite to growth; yet, the presence of a high folate concentration also results in a fivefold increase in the cellular tolerance for this anion. A 50% growth inhibition is attained with 30 μM arsenate in 0.2 μM folate medium, while 150 μM is needed in 2.0 μM culture medium. Dimethylarsinate (DMA) is much less inhibitory to cell growth than either of the inorganic forms. DMA concentrations of 1.2–1.5 mM are required to inhibit growth 50% and a high folate medium makes CHO‐S cells slightly more susceptible to its growth inhibition than a low folate medium. All three forms of arsenic cause the cells to increase in size, but the characteristics of the enlargements are different. Edema and mitochondrial enlargement are two of the most obvious changes in cells exposed to arsenite. The nucleus has large irregular, electron dense inclusions after exposure to arsenate, but the cytoplasm is not as swollen in response to this inorganic form. Both inorganic forms of arsenic result in a breakdown of membrane components and cause the ribosomes to detach from the endoplasmic reticulum and aggregate in the cytoplasm. DMA exposure does not result in generalized mitochondrial swelling and loss of endoplasmic reticulum, but it markedly inhibits mitosis. CHO‐S cells treated with 4.0 mM DMA (90% growth inhibition) contain multiple nuclei, 22% mitotic figures, and clusters of intermediate filaments in their cytoplasm.

ISSN:0360-1226    

DOI:10.1080/10934528509375209

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The effect of 120‐day exposure to a high‐intensity (80 kV/m), 60‐Hz electric field on histology of selected internal organs of Sprague‐Dawley rats was investigated. The organs examined were the pituitary, thymus, heart, lungs, liver, spleen, right and left adrenals, right and left kidneys, and right and left testes. Histological examination of 10‐micron tissue sections from randomly selected animals revealed no specific evidence of histopathologic differences between field‐exposed and sham‐exposed animals at the light microscopic level.

ISSN:0360-1226    

DOI:10.1080/10934528509375210

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Microporous N‐containing activated carbon (N‐CAC) suitable for hydrogen sulfide adsorption was prepared by impregnating raw activated carbon with a 25% methylol melamine urea solution and then heating it at different temperatures from 100 to 1000°C. The structures of raw activated carbon and N‐CAC Ho. 8 carbonized at the most suitable temperature 850°C have been discussed based on applying the Dubinin‐Radushkevich equation to adsorption isotherm of hydrogen sulfide. The 12.2% increase in micropore volume of N‐CAC No. 8 result from the numerical increase of micropores rather than radial expansion of micropores. The relation of q and AS could be consistently explained by the interaction of hydrogen sulfide with micropores of adsorbents.

ISSN:0360-1226    

DOI:10.1080/10934528509375211

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Ultrafiltration is demonstrated to be an effective method for characterizing industrial landfill leachates by molecular weight (MW) distribution. The majority of the organic matter (as TOC and COD) for the hazardous wastes examined was found to be below 500 MW. The applicability of ultrafiltration as an effective process for removal of low MW organic matter from industrial wastes is limited. Ultrafiltration, however, is useful as a pretreatment process for removal of large MW compounds that interfere with subsequent treatment processes. Ultrafiltration of raw landfill leachates is hindered by concentration polarization and severe fouling. Physiochemical lime treatment of the highly turbid raw leachate was found to aid in the stabilization of product flux.

ISSN:0360-1226    

DOI:10.1080/10934528509375212

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

STUDIES IN GEOPHYSICS GROUNDWATER CONTAMINATION BY GEOPHYSICS STUDY COMMITTEE. Natural Research Council National Academy Press. Washington, D.C. 1984, 178p plus XII, paperback $17.95

ISSN:0360-1226    

DOI:10.1080/10934528509375213

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0360-1226    

DOI:10.1080/10934528509375206

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor