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排序方式: 共有230条查询结果,搜索用时 15 毫秒
21.
J. Staehelin A. Waldvogel J. L. Collett Jr. R. Dixon R. Heimgartner W. Henrich C. Hsu L. Li L. Mosimann B. Oberholzer A. S. H. Prevot W. Schmid T. Schumann M. Steiner M. Volken B. Zinder 《Water, air, and soil pollution》1993,68(1-2):1-14
Wet deposition plays an important role as a mechanism for cleansing of the polluted troposphere. Fluxes of pollutants from the atmosphere to earth's surface can affect soil and aquatic ecosystems. The investigation of the pollutant incorporation into wet deposition is therefore of considerable interest for environmental research. The project “Winter precipitation at Mount Rigi” addresses the processes determining the chemical composition of wet deposition through an integrated approach considering atmospheric physical and chemical processes and their complex interactions. The investigated topics include: aerosol and gas scavenging, atmospheric chemistry (cloud water chemistry), cloud physics and dynamics. The design of the experiment, using three ground based measuring stations at the northwestern slope of the mountain, and the conceptual ideas using case study investigations are discussed. 相似文献
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The effects of H2 gas treatment of an agricultural soil cultivated previously with a mixture of clover (Trifolium pratense) and alfalfa (Medicago sativa) on CO2 dynamics and microbial activity and composition were analyzed. The H2 emission rate of 250 nmol H2 g−1 soil h−1 was similar to the upper limit of estimated H2 amounts emitted from N2 fixing nodules into the surrounding soil ([Dong, Z., Layzell, D.B., 2001. H2 oxidation, O2 uptake and CO2 fixation in hydrogen treated soil. Plant and Soil 229, 1-12.]). After 1 week of H2 supply to soil samples simultaneously with H2 uptake net CO2 production declined continuously and this finally led to a net CO2 fixation rate in the H2-treated soil of 8 nmol CO2 g−1 soil h−1. The time course of H2 uptake and CO2 fixation in the soils corresponded with an increase in microbial activity and biomass of the H2-treated soil determined by microcalorimetric measurements, fluorescence in situ hybridization analysis (FISH) and DNA staining (DAPI). Shifts in the bacterial community structure caused by the supply of H2 were recorded. While the H2 treatment stimulated β-and γ-subclasses of Proteobacteria, it had no significant effect on α-Proteobacteria. In addition, FISH-detectable bacteria of the Cytophaga-Flavobacterium-Bacteroides phylum increased in numbers. 相似文献
23.
Caris-Veyrat C Schmid A Carail M Böhm V 《Journal of agricultural and food chemistry》2003,51(25):7318-7325
The aim of this study was to produce in vitro oxidation products of lycopene, which could be possible in vivo metabolites. An oxidation of lycopene with potassium permanganate gave a range of lycopene degradation compounds resulting from the oxidative cleavage of one or two carbon-carbon double bonds. Eleven apo-lycopenals/ones and six apo-carotendials were obtained and tentatively characterized by HPLC-DAD-MS. Apo-11-lycopenal and apo-8,6'-carotendial were isolated and characterized by (1)H NMR for the first time. Lycopene was submitted to an oxidation by atmospheric oxygen catalyzed by a metalloporphyrin, a model system of the active center of cytochrome P450 enzymes. (Z)-Isomers, monoxides, and cleavage compounds of (E)-lycopene were formed. We propose a mechanism of oxidation of lycopene by this system. 相似文献
24.
Objective: To describe a technique used for reduction and internal fixation of sacral fractures in cattle. Study Design: Case series. Animals: Three heifers aged 19–32 months with deformation of the tail head and tail paralysis attributable to a closed fracture of S5 or S4 and S5. Methods: Fractures were reduced and repaired under general anesthesia. A narrow, 6–10‐hole, locking compression plate (LCP) was placed on the spinous processes of S5 and the first coccygeal (Co1) using 5.0 mm locking head screws. Follow‐up inquiries were made by telephone (3/3), and cows were examined clinically and radiographically 2 (1 cow) to 9 (1cow) months postoperatively. Results: No complications were encountered. The range of movement of the tail improved so that soiling of the tail during defecation was no longer a problem. In all heifers, the normal top line was restored and there was no narrowing of the pelvic canal. Unassisted calving occurred in all heifers, and follow‐up radiographs for 2 cows showed complete fracture healing. Conclusion: LCP‐osteosynthesis of the spinous processes provided sufficient stability for internal fixation of sacral fractures. Marked improvement in tail function occurred postoperatively without decompression by laminectomy. 相似文献
25.
R. Hoffmann D.O. Schmid G. Hoffmann-Fezer 《Veterinary immunology and immunopathology》1981,2(2):111-119
Autoimmune hemolytic anemia (AIHA) was detected in pigs affected by spontaneous eperythrozoonosis. Autoantibodies against red cells were found by hemagglutination and hemolysin tests and direct and indirect antiglobulin tests using immunofluorescence. According to these findings and morphological results, the process in porcine eperythrozoonosis is to be classified as acquired autoimmune hemolytic anemia due to “cold” antibodies. 相似文献
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The neonatal depression of puppies, developed by C-section, can be treated effectively by the application of 0.1-0.2 ml Narcanti respectively Narcanti Neonatal (Naloxon) right after development. The technique of the intravenous injection in newborn puppies is simple and easy to learn. 相似文献
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