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21.
The characteristics of the five Korean isolates of Japanese encephalitis (JE) virus were compared with those of the already reported JE virus strains from Japan and China using the hemagglutination test and polymerase chain reaction direct sequencing of the JE virus genomes (capsid/premembrane, envelope region). The hemagglutination patterns of all the isolates were distinctly different from the Nakayama-NIH strain. The optimal pH of hemagglutination of all the Korean isolates was 6.6-7.0 and the reaction range was broader than that of the Nakayama-NIH strain. The 198 nucleotide sequences in the capsid/premembrane gene region of the five Korean strains indicated that they were classified into the third genotype group, the JE strains from the countries in the temperate zone including the Nakayama-NIH, JaOArS982, and Beijing-1 strains. Four of the five Korean isolates formed a unique phylogenetic tree within the third genotype group, although the last one was genetically highly related to the Nakayama-NIH strain. The 251 nucleotide sequences in the envelope region of the five isolates were more divergent than the capsid/premembrane region. Four of the five isolates showed a large nucleotide divergency as compared with the JaOArS982 strain (< or = 12.4%), but the last one was similar to the JaOArS982 strain (98% of nucleotide homology). These results suggest the evolutionary divergence of the JE viruses isolated in Korea from the Japanese and Chinese strains and that there may exist at least two antigenically different JE virus strains in Korea. 相似文献
22.
神经网络在电路诊断中的应用 总被引:6,自引:1,他引:5
目的:阐述了目前电路基于数据库技术和人工智能专家系统及神经网络原理的故障诊断系统。方法:将所记录的模糊症状输入到系统中,通过模糊运算后,运用神经网络学习算法来寻找故障类型。结果:介绍了人工神经网络技术在电路诊断中的应用,并给出系统故障诊断软件的设计,结论:所用专家系统和神经网络相结合的方法改进电子电路故障诊断是可行的。 相似文献
23.
实时数据库及时准确地从现场获取数据并有效地组织和管理,是水电厂 设备故障诊断系统进行故障诊断的首要条件。文中在分析了现有的实时数据库实现方法后, 用C++ Builder 5.0和SQL Server 7.0完成了实时数 据库实现的一种简洁方法,它不但能够满足工程需要,而且具有关系数据库所具有的一切强 大的数据库管理和维护功能,实现也很简单,极大地节省了实时数据库开发的人力和物力。 实验表明,该方法是可行的。 相似文献
24.
The hypocotyl of Arabidopsis is well suited for the analysis of cell elongation because it elongates without cell division. We have isolated a new class of recessive mutants, petit1 (pet1), which are defective in aspects of hypocotyl elongation. The short-hypocotyl phenotype of pet1 is caused by shortened cells. The cells of the elongation zone of the hypocotyl are often deformed. pet1 also shows defects in elongation of the roots, flower stalk, leaves, petals, pedicels, and siliques, and these defects cannot be repaired by the application of auxin, gibberellin, brassinolide, or an inhibitor of ethylene biosynthesis. The short-hypocotyl phenotype of pet1 is pronounced only in growth medium supplemented with sucrose, which has promotive effects on hypocotyl elongation. In pet1 this effect is much reduced, causing the sucrose-dependent short-hypocotyl phenotype of pet1. pet1 accumulates more soluble sugars than the wild type and also shows more intensive iodo-starch staining in the cotyledon and hypocotyl. These results indicate that PETIT1 is involved in a sugar-dependent elongation process that may include correct assembly of expanding cell wall architecture. 相似文献
25.
Tannic acid, propyl gallate and methyl gallate, but not gallic acid, were found to be inhibitory to the growth of intestinal bacteria Bacteroides fragilis ATCC 25285, Clostridium clostridiiforme ATCC 25537, C. perfringens ATCC 13124, C. paraputrificum ATCC 25780, Escherichia coli ATCC 25922, Enterobacter cloacae ATCC 13047, Salmonella typhimurium TA98 and S. typhimurium YG1041 at 100-1000 microg/ml in culture broth. Neither Bifidobacterium infantis ATCC 15697 nor Lactobacillus acidophilus ATCC 4356 was inhibited by any of the above compounds up to 500 microg/ml. Tannic acid has a much greater relative binding efficiency to iron than propyl gallate, methyl gallate or gallic acid. The inhibitory effect of tannic acid to the growth of intestinal bacteria may be due to the strong iron binding capacity of tannic acid; whereas the effect of propyl gallate and methyl gallate probably occurs by a different mechanism. The growth of E. coli was restored by the addition of iron to the medium after the precipitate caused by tannic acid was removed. Neither B. infantis nor L. acidophilus require iron for growth. This probably contributes to their resistance to tannic acid. Because tannins are abundant in the human diet, tannins may affect the growth of some intestinal bacteria and thus may have an impact on human health. 相似文献
26.
Villin 14T, a representative domain from the actin severing and bundling protein villin, binds calcium ions and actin monomers. To begin to understand the contributions of mobility to the villin-calcium and villin-actin interactions, relaxation rates for magnetization involving the amide nitrogens and protons have been measured for 15N-labeled villin 14T in solution. Although we have measured the complete set of rates required for a full spectral density map, difficulties in the accurate measurement of relaxation rates for antiphase coherence and two-spin order led us to consider a reduced mapping formalism. From the reduced spectral density map, a model-free analysis, or directly from the measured Nx,y relaxation rates, local variations in mobility along the backbone of villin 14T have been revealed. Fast motions are evident not only at the amino and carboxyl termini but also in the turn between strands beta 4 and beta 5 of the central beta-sheet and in the turn between helix alpha 3 and strand beta 7. Slower motions are suggested for the turn between strands beta 2 and beta 3. Motions on the microsecond to millisecond time scale have been probed directly by examining the dependence of the proton transverse relaxation rate on the spin-locking field strength. Leu11 shows a strong dependence on field strength, implying conformational exchange with a time constant of 125 +/- 69 microseconds. The backbone at the actin-binding interface appears to be rather rigid. 相似文献
27.
Human immediate hypersensitivity diseases represent the most common example of chronic excessive Th2-like activation in developed nations. While IL-13 shares many functional properties with IL-4, the intensity and regulation of environmental Ag-stimulated IL-13 synthesis by allergic vs nonallergic individuals remain ill defined. Here, we examine the intensity of polyclonally and Ag-stimulated IL-13 production by PBMC of 20 subjects with seasonal allergic rhinitis and 20 healthy controls. Polyclonally driven IL-13 responses did not differ significantly (Mann-Whitney U test, p = 0.68). In contrast, the median CD4-dependent IL-13 response among atopics was markedly stronger than nonatopics in Ag-stimulated primary culture (p = 0.0031) and exhibited a strong correlation with IL-5 (r = 0.76, p = 0.0009), but not IL-4 (r = 0.14, p > 0.05), responses. IL-13 production was unaffected by blocking endogenous IL-4 or IL-5 activity or by addition of rIL-4 or rIL-5. In contrast, it was inhibited by low levels of rIFN-gamma and strongly enhanced upon addition of neutralizing anti-IFN-gamma mAb. Collectively, the data are consistent with a negative regulatory role for endogenous IFN-gamma synthesis in controlling the intensity of systemic IL-13 responses evoked in both atopic and nonatopic populations following exposure to common Ags. They also suggest that the elevated levels of IL-4 and IL-5 characteristic of type 2-dominated responses in vivo are without detectable impact on the maintenance of recall Ag-stimulated IL-13 production. 相似文献
28.
29.
地方时与区时在电离层研究中的差异 总被引:2,自引:0,他引:2
本文指出混淆地时与区时两个时间概念在电离层研究中带来的差异的严重性,建议使用地方与区时这两个名词,而抛弃“本地时”和“当地时”等容易引起混淆的名词。 相似文献
30.
为了解和掌握台儿庄城区饮用水水源地放射性水平和动态变化,本文以枣庄市生态环境局台儿庄分局提供的饮用水水源地水质放射性数据为基础,探讨了台儿庄城区饮用水水源地水质中α、β放射性质量浓度的动态变化。结果显示:水源地总α、β放射性质量浓度均低于标准限值,总α放射性质量浓度小于总β放射性质量浓度,总α、β放射性水平在水源地和季节变化中差异均不显著(P>0.05)。水源地水质总放射性水平符合我国规定的饮用水指导值。 相似文献