排序方式: 共有33条查询结果,搜索用时 390 毫秒
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Shubo Tatsuo Maranhão Adriana Ferreira Fernando César Fumian Tulio Machado Pimenta Márcia Maria Araújo do Rosário Vaz Morgado Cláudia Toze Simon Ahmed Warish Sidhu Jatinder Miagostovich Marize Pereira 《Food and environmental virology》2021,13(3):412-420
Food and Environmental Virology - Roof-harvested rainwater (RHRW) is considered relatively clean water, even though the possible presence of pathogens in the water may pose human health risks. In... 相似文献
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In this study, the TiO2 photocatalytic decomposition process of aqueous phenol was investigated. The intermediate products generated in the elementary reaction steps in the mineralization process were experimentally identified as hydroquinone, catechol and hydroxyhydroquinone. The concentration variations of these intermediate products with time passage were traced by high performance liquid chromatograph. The pathways of the decomposition process were given. Based on Langmuir isothermal theory and Langmuir-Hinshelwood mechanism, the multi-compounds competition kinetic model was established. In this model, the observed time-dependent concentrations of phenol and the intermediate products were simulated. 相似文献
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The excess growth of cyanobacteria in semi enclosed water areas caused by eutrophication brings about coagulation inhibition in drinking water treatment processes. In this study, coagulation inhibitor proteins produced by Microcystis aeruginosa, a major cyanobacterium in algal bloom, were acquired by a phage display technique, an aluminum-immobilized affinity chromatography and a protein expression technique using Escherichia coli cells. Two cyanobacterial peptides with a high ratio of metallophilic amino acids were recovered, which were a part of homologues of a thiol oxidase enzyme Ero1p and a trans-acting repressor ArsR. It was also shown that the homologue of ArsR exhibited a stronger inhibitory effect on the coagulation of kaolin suspension with polyaluminum chloride than the control proteins. This is the first report to identify a cyanobacterial cell component to inhibit coagulation. The compositions of polar amino acids were critical to explain the strength of coagulation inhibition potential. Polar proteins from cyanobacteria could collectively consume coagulants or stabilize clay particles, which would be plausible explanations for causing coagulation inhibition. Meanwhile, results from the kaolin coagulation tests using the control proteins implied that the neutralization of positive charges of coagulant constituents by simple electrostatic interactions might not be the key mechanism on the protein-induced coagulation inhibition. 相似文献
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Degradation of microcystins using immobilized microorganism isolated in an eutrophic lake 总被引:4,自引:0,他引:4
The final purpose of our series of studies is to establish a biological removal method of cyanobacteria and their toxic products using immobilized microorganisms that can lyse cyanobacteria and decompose microcystins. To establish the biological removal method in non-point areas and water purification plants, as the first step, we explored bacteria active against the cyanobacterial hepatotoxin microcystin in the present study. Eleven active bacteria were isolated from samples taken from Lakes Tsukui and Sagami, Japan. Among 3 strains (B-9 to B-11) with degradative activity, strain B-9 exhibited the strongest activity. The 16S rDNA sequence of the strain B-9 showed the highest similarity to that of Sphingomonas sp. Y2 (AB084247, 99% similarity). Microcystins-RR and -LR were completely degraded by strain B-9 (SC16) within 1d, which led to an immobilized microorganism with a polyester resin. The degradation of microcystin-RR in a bioreactor using the immobilized strain B-9 was observed and microcystin-RR (> 90%) was completely degraded after 24 h. Microcystin-RR was added to the lake water at regular intervals and the degradation after 24 h was observed in the bioreactor over a 72-d period. An over 80% removal efficiency continued for 2 months, showing that the life of the immobilized B-9 in terms of activity was at least 2 months under the optimized conditions. From these results, this immobilized B-9 is feasible for the practical treatment of microcystins in non-point areas and water purification plants. 相似文献
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An efficient sampling method for dioxins from flue gas, an efficient automatic purification and fractionation method by a new HPLC system using a sulfuric acid-silica/silica column, a Nitro column and a PGC column, and sensitive determination method by an economical HRGC/LRMS using a programmable temperature vaporization (PTV) injector were developed. It was confirmed that the dioxins could be easily collected by the proposed simple sampling train consisting of only two bottles, and the extracted sample could be purified sufficiently and separated as mono-ortho PCBs, non-ortho PCBs and PCDDs/PCDFs completely with the proposed HPLC system. The peak areas of GC/MS were increased linearly with the injection volume up to 40 microl by the PTV technique, and the sensitivity could be increased to 20 times higher than usual. This convenient measuring method can drastically reduce operation time, consumption of hazardous solvent and cost. 相似文献
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Nakanishi T Zheng J Aono T Yamada M Kusakabe M 《Journal of environmental radioactivity》2011,102(8):774-779
Using a sector-field ICP-MS the vertical distributions of the 99Tc concentration and 99Tc/137Cs activity ratio were measured in the coastal waters off Aomori Prefecture, Japan, where a spent-nuclear-fuel reprocessing plant has begun test operation. The 99Tc concentrations in surface water ranged from 1.8 to 2.4 mBq/m3, no greater than the estimated background level. Relatively high 99Tc/137Cs activity ratios (10-12 × 10−4) would be caused by the inflow of the high-99Tc/137Cs water mass from the Japan Sea. There is no observable contamination from the reprocessing plant in the investigated area. The 99Tc concentration and the 99Tc/137Cs activity ratio in water column showed gradual decreases with depth. Our results implied that 99Tc behaves in a more conservative manner than 137Cs in marine environments. 相似文献