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Use of limestone for pH control in autotrophic denitrification: continuous flow experiments in pilot-scale packed bed reactors 总被引:1,自引:0,他引:1
The sulfur-utilizing autotrophic denitrification process consumes about 4 g alkalinity (as CaCO(3)) per g NO(3)-N reduced resulting in a decrease of pH. Using limestone as an alkalinity source to control the pH, autotrophic denitrification of synthetic wastewater with varying alkalinity to NO(3)-N ratios was evaluated in pilot-scale packed bed reactors operating in the upflow mode, which contained limestone and sulfur granules in different volumetric ratios. The results demonstrated that limestone supplies effective buffering capacity, if the initial alkalinity of the wastewater is insufficient for complete denitrification. The alkalinity supplied by limestone is a function of hydraulic retention time and the pH, which in turn depends on the extent of biological denitrification and the initial alkalinity to NO(3)-N ratio in the wastewater. The dissolution rate of limestone is inversely proportional to pH for pH values lower than 7.1. It was found that the ratio of influent alkalinity to theoretically required alkalinity in the wastewater should not be lower than 0.5 in order to prevent a decrease in nitrate removal performance. Based on the established chemical-biological interactive relationships, a multilayer approach was proposed to determine the optimum sulfur:limestone ratio for nitrate removal under steady state conditions, taking into account the characteristics of the influent wastewater. 相似文献
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Human caspase 12 has acquired deleterious mutations 总被引:29,自引:0,他引:29
Fischer H Koenig U Eckhart L Tschachler E 《Biochemical and biophysical research communications》2002,293(2):722-726
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A widely applicable strategy is presented for efficient and rapid production of small water soluble peptides expressed as fusion proteins with the immunoglobulin-binding domain of streptococcal protein G. A simple extraction and purification scheme that includes a protease cleavage step to release the target peptide is described. The yield of authentic target peptide exceeds 10 mg per liter of culture. Production of U-13C, 15N and highly deuterated U-13C, 15N isotope labeled peptide is demonstrated for the 11 residue S2 peptide, corresponding to the C-terminus of the -subunit of transducin, and the coiled coil trimerization domain from cartilage matrix protein (CMPcc), respectively. Heteronuclear two-dimensional NMR spectra are used for initial peptide characterization. 相似文献
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Lopiano L Fasano M Giraudo S Digilio G Koenig SH Torre E Bergamasco B Aime S 《Neurochemistry international》2000,37(4):331-336
Nuclear Magnetic Relaxation field-cycling relaxometry is a technique, able to report on water mobility in tissues. By means of this technique, post-mortem specimens from both controls and idiopathic Parkinson's disease patients have been investigated. Results show different relaxometric behavior between the groups, which is consistent with protein aggregation in Parkinson's disease specimens. 相似文献
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Koenig J. H. Ikeda Kazuo 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1983,151(3):295-310
Journal of Comparative Physiology A - Intracellular recordings were made from the motor neurons which innervate the dorsal longitudinal flight muscle (DLM) inDrosophila, while a normal-appearing... 相似文献
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Roshan B. Christensen J. R. Christensen Ian Koenig Christopher W. Lawrence 《Molecular & general genetics : MGG》1985,201(1):30-34
Summary Using a nonselective method, we have estimated the proportion of untargeted mutations in the lacI gene of E. coli by transferring either irradiated or unirradiated F pro lac plasmids from an excision deficient donor to an excision deficient pro lac deleted recipient that had been irradiated and allowed to induce recA dependent functions for 30 min. We find that about 10 percent of the mutations induced by either 3.5 Jm-2 or 7 Jm-2 UV are untargeted. 相似文献