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排序方式: 共有365条查询结果,搜索用时 15 毫秒
21.
Arts MJ Grun C de Jong RL Voss HP Bast A Mueller MJ Haenen GR 《Journal of agricultural and food chemistry》2007,55(17):7010-7014
Although hardly any polyunsaturated fatty acids (PUFAs) are present in the endproduct, the ingredients used for the production of beer contain a high concentration of PUFAs, such as linolic and linolenic acid. These compounds are readily oxidized, resulting in the formation of lipid-derived products that reduce the taste and quality of beer enormously. During mashing relatively high amounts of PUFAs are exposed to atmospheric oxygen at a relatively high temperature. This makes mashing a critical step in the brewing process with regard to the formation of lipid-derived off-taste products. F1 phytoprostane (PPF1) changes in antioxidant capacity and monohydroxy fatty acids (OH-FAs) were used as markers for the detection of oxidative damage to fatty acids during mashing. The pattern of OH-FA formation indicates that enzymatic oxidation of PUFAs is more important than nonenzymatic oxidation during the mashing process. Nevertheless, substantial nonenzymatic radical formation is evident from the increase of specific OH-FAs and PPF1s. It was found that a low oxygen tension reduces oxidative damage and gives a high antioxidant capacity of the mashing mixture. This indicates that mashing should be done under low oxygen pressure. 相似文献
22.
Significant numbers of perch, Perca fluviatilis, raised on a pilot fish farm in Switzerland presented focal skin lesions on the lateral sides and fin rot. Mortality rates reached levels of up to 1% of the total fish on the farm per day. Virtually pure cultures of Aeromonas sobria were isolated from the liver, kidney, spleen and skin lesions of affected fish. Aeromonas sobria isolated from the farmed perch had a haemolytic effect on sheep and trout erythrocytes, autoaggregated, was cytotoxic for cultured fish cells and possessed genes involved in type III protein secretion. Experimental infection of naive perch with a single colony isolate of A. sobria from an affected farm fish resulted in the development of clinical signs identical to those seen on the farm. The results indicate that A. sobria can act as a primary pathogen of perch. 相似文献
23.
Effects of radial shockwave therapy on the limb function of dogs with hip osteoarthritis 总被引:1,自引:0,他引:1
The objective of this study was to evaluate the effects of extracorporeal radial shock wave therapy on the hindlimb function of dogs suffering from hip osteoarthritis. Twenty-four client-owned dogs with hip osteoarthritis were investigated; 18 of them received radial shockwave therapy and six were left untreated as controls. Force plate analysis on a treadmill was used to assess the dogs' hindlimb function before treatment and four weeks after the last treatment, and the treated dogs were re-evaluated three and six months after the treatment. The parameters chosen for evaluation were peak vertical force and vertical impulse, and the calculated symmetry indices. In the treated dogs, differences between the ground reaction forces exerted by the right and left hindlegs disappeared four weeks after the treatment, whereas in the control dogs only the peak vertical force distribution changed significantly. The significant improvement in the treated dogs was confirmed by changes in the symmetry indices. Significant improvements in vertical impulse and peak vertical force were observed three months after the treatment. 相似文献
24.
Riley MB Dumas JA Gbur EE Massey JH Mattice JD Mersie W Mueller TC Potter T Senseman SA Watson E 《Journal of agricultural and food chemistry》2005,53(13):5079-5083
An interlaboratory study was conducted to compare pesticide recovery from Empore C(18) and Speedisks C(18)XF solid phase extraction disks after shipping. Four pesticides were used for the comparison of the two disk extraction materials: atrazine, diazinon, metolachlor, and tebuconazole. These pesticides were chosen to provide a range of physiochemical properties. Water samples were extracted onto the disk types and shipped to a cooperating laboratory for elution and analysis. The mean recoveries from Empore disks were atrazine, 95%; diazinon, 91%; metolachlor, 92%; and tebuconazole, 83%. The recoveries from Speedisks C(18)XF were atrazine, 89%; diazinon, 87%; metolachlor, 86%; and tebuconazole, 79%. Means for each of the pesticides using the different disk types were not statistically different (alpha = 0.05), but results were more variable when using Speedisks C(18)XF as compared to Empore disks. Reasons for the increased variability are discussed, but overall results indicate that Speedisks C(18)XF could be used as an alternative to Empore disks. Speedisks C(18)XF are enclosed in a plastic housing, so they can be used more easily in remote sampling sites without the possibility of glassware breakage, no prefiltration of samples is needed, and there are realignment problems that can be associated with the Empore disks. 相似文献
25.
Hovis WA Clark DK Anderson F Austin RW Wilson WH Baker ET Ball D Gordon HR Mueller JL El-Sayed SZ Sturm B Wrigley RC Yentsch CS 《Science (New York, N.Y.)》1980,210(4465):60-63
The Coastal Zone Color Scanner (CZCS) on Nimbus-7, launched in October 1978, is the only sensor in orbit that is specifically designed to study living marine resources. The initial imagery confirms that CZCS data can be processed to a level that reveals subtle variations in the concentration of phytoplankton pigments. This development has potential applications for the study of large-scale patchiness in phytoplankton distributions, the evolution of spring blooms, water mass boundaries, and mesoscale circulation patterns. 相似文献
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28.
Mueller CA Broz P Müller SA Ringler P Erne-Brand F Sorg I Kuhn M Engel A Cornelis GR 《Science (New York, N.Y.)》2005,310(5748):674-676
Many pathogenic bacteria use injectisomes to deliver effector proteins into host cells through type III secretion. Injectisomes consist of a basal body embedded in the bacterial membranes and a needle. In Yersinia, translocation of effectors requires the YopB and YopD proteins, which form a pore in the target cell membrane, and the LcrV protein, which assists the assembly of the pore. Here we report that LcrV forms a distinct structure at the tip of the needle, the tip complex. This unique localization of LcrV may explain its crucial role in the translocation process and its efficacy as the main protective antigen against plague. 相似文献
29.
Adrenal tyrosine hydroxylase: compensatory increase in activity after chemical sympathectomy 总被引:11,自引:0,他引:11
Destruction of peripheral sympathetic nerve endings with 6-hydroxydopamine causes a disappearance of cardiac tyrosine hydroxylase, accompanied by a twofold increase in adrenal tyrosine hydroxylase and a small increase in phenyl-ethanolanine-N-methyl transferase. No change in adrenal catecholamine content occurs under these conditions. 相似文献
30.
The measured voltage derivative of the nonlinear resistance of tiny point contacts can be separated into a phonon-emission effect (alpha(2)F) and an analytic functional form (background effect). The alpha(2)F's show structure coincident with bulk phonon densities of states. Values of the integral of 2 alpha(2)F/omega are closely related to literature values. The background effect is related to the impurity concentration of the materials. 相似文献