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排序方式: 共有3399条查询结果,搜索用时 31 毫秒
171.
JM Koelman HJ Noteborn de Goey LP BJ Verhaar JT Walraven 《Canadian Metallurgical Quarterly》1985,32(11):7195-7198
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SN Reske HJ Biersack K Lackner HJ Machulla R Knopp N Hahn C Winkler 《Canadian Metallurgical Quarterly》1982,21(6):249-253
The utility of myocardial imaging and assessment of regional myocardial metabolism of omega-(123I-paraphenyl-)pentadecanoic acid (I-PPA) by means of serial single-photon tomography is demonstrated in animal experiments. High quality cross sectional images of dog hearts with clear delineation of left ventricular walls are obtained. Myocardial infarcts are visualized as areas of deficient radioactivity uptake. I-PPA elimination from non-infarcted myocardial regions is significantly (p less than 0.001) prolonged when compared with unaffected controls. Hence, not only localized absence of uptake of free fatty acid by infarcted myocardium can be demonstrated with serial single-photon tomography but also general impairment of cardiac FFA-metabolism. 相似文献
175.
Testosterone and the testosterone precursors pregnenolone, progesterone, 17 alpha-hydroxyprogesterone, 17 alpha-hydroxypregnenolone, androstenedione, androstenediol and dehydroepiandrosterone were measured in the spermatic vein plasma and in the testicular tissue of young and old men. Testosterone and its precursors decreased in the testicular tissue of old men. However, progesterone and 17 alpha-hydroxyprogesterone increased in relation to testosterone in the testicular tissue and in the spermatic vein of old men. It is assumed that these age-dependent changes are caused by an impaired oxygen supply of the ageing testes. This hypothesis is supported by the observation that the same changes in steroid pattern seen in old age can be observed under reduced oxygen supply in in vitro incubation experiments with testicular tissue. 相似文献
176.
L Hougs L Juul HJ Ditzel C Heilmann A Svejgaard T Barington 《Canadian Metallurgical Quarterly》1999,162(1):224-237
The Ab response of a healthy adult to the first dose of a Haemophilus influenzae type b capsular polysaccharide (HibCP) conjugate vaccine was studied at the level of Ig gene usage by circulating Ab-secreting cells. Forty-one IgA and 17 IgG mRNA sequences were obtained. The major part of the response was confined to IgA Ab-secreting cells, and 72% of the IgA sequences were derived from the progeny of a single rearranged B cell. These sequences could be arranged in a genealogical tree showing multiple somatic mutations and at least two intraclonal isotype switches to IgA2. Fourteen somatic mutations were shared by this clonal progeny, indicating that extreme clonal selection had occurred early in the clonal development. Taking into account the frequency of somatic mutations and the clone size, it was evident that the responding cell population must have originated from a mutated, highly selected, and expanded population of cells existing before vaccination, i.e., memory B cells. The dominating heavy and light chains of the response were combined in a Fab that bound HibCP. It was shown that the shared heavy and light chain mutations increased the affinity for HibCP considerably, indicating that the clonal selection had been driven by affinity. Pre-existing memory cells in unvaccinated adults may explain several features of Ab responses to polysaccharide vaccines and may play a role in acquiring the ability to respond to pure polysaccharides during infancy. 相似文献
177.
Vincenzo Liso Anders Christian OlesenMads Pagh Nielsen Søren Knudsen Kær 《Energy》2011,36(7):4216-4226
The aim of this research work is to describe in qualitative and quantitative form the performance of a micro Combined Heat and Power system for residential application based on Solid Oxide Fuel Cell fueled by natural gas with two different types of pre-reforming systems, namely Steam Reforming and Partial Oxidation and recirculation of anode and cathode gas.The comparative analysis among the different configurations will lead us to conclude that maximum efficiency is achieved when cathode and anode gas recirculation are used along with steam methane reforming. Further Steam Methane Reforming process produces a higher electrical system efficiency compared to Partial oxidation reforming process.Efficiency is affected when running the system in part load mode mainly due to heat loss, additional natural gas supplied to the burner to satisfy the required heat demand inside the system, and ejector efficiency drop in the recirculation system. Due to high temperature of operation heat loss strongly affects the system efficiency especially at part load operation. 相似文献
178.
A synergistic effect of high concentration of chloride and H2S on oxide formation and metal dissolution has been studied on 316L stainless steel by electrochemical measurements, inductive coupled plasma (ICP) and X-ray photoelectron spectroscopy (XPS). Chloride concentration had a significant effect on semiconductor properties of the oxide film, while the gases had little effect. A relatively high concentration of sulphur was found inside the oxide formed in a high chloride concentration electrolyte with high H2S compared to the oxide formed in low concentrations, which indicates that sulphur entered the oxide film through local weakening of the oxide by the chloride. 相似文献
179.
Neuromuscular disease commonly affects the rearfoot as equinus, equinovarus, and equinovalgus deformity. Spastic hemiplegia caused by stroke, head injury, and cerebral palsy results in equinovarus deformity of the rearfoot. Spastic diplegia, most frequently caused by cerebral palsy, results in equinovalgus rearfoot deformity. Problems in ambulation, footwear, and bracing, as well as their orthopedic management, in patients with neuromuscular disease are discussed in a case-report format. 相似文献
180.