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C-reactive protein (CRP) is a prototypic acute phase protein in human and rabbit. Although it is structurally and functionally conserved from invertebrate to human, there are species-specific differences in patterns of expression and putative function. To further investigate the biological significance, regulation, and evolution of CRP, we isolated Xenopus CRP and subsequently derived and sequenced corresponding cDNA and the genomic clones. The structure and expression of Xenopus CRP were also compared to those of the other CRPs. Analyses of the amino acid sequence and the nucleotide sequence reveal that the mature Xenopus CRP is a 222-amino acid protein preceded by a 16-residue signal peptide. During development, Xenopus CRP is expressed, only when the liver appears, and therefore is not likely to play a role in early embryonic development. Compared to other species, Xenopus CRP is present at an intermediate low level of < 1 microgram/ml in the normal serum. Unlike human and rabbit CRP, Xenopus CRP is not induced by turpentine or heatshock treatment. The heatshock consensus sequence (Woo, P., Korenberg, J. R., and Whitehead, A. S. (1985) J. Biol. Chem. 265, 4136-4142) are not present in the Xenopus CRP gene. It is suggested that Xenopus CRP represents a transitional period in CRP evolution when host defenses switched from primitive innate immunity to a much more complex immune system. The constitutive functions of CRP gradually became less essential as the result of the development of a complex immune system. 相似文献
75.
Lin Yuan Kesavan H.K. 《IEEE transactions on systems, man and cybernetics. Part C, Applications and reviews》1998,28(3):488-491
Kapur et al. (1995) introduced the MinMax information measure, which is based on both maximum and minimum entropy. The major obstacle for using this measure, in practice, is the difficulty in finding the minimum entropy. An analytical expression has already been developed for calculating the minimum entropy when only variance is specified. An analytical formula is obtained for calculating the minimum entropy when only mean is specified, and numerical examples are given for illustration 相似文献
76.
Chih-Chun Hsieh Tao-Chih Chang Dong-Yih Lin Ming-Che Chen Weite Wu 《Metals and Materials International》2007,13(5):411-416
The purpose of this study is to investigate the precipitation characteristics of σ phase in the fusion zone of stainless steel
welds at various welding passes during a tungsten are welding (GTAW) process. The morphology, quantity, and chemical composition
of the δ-ferrite and σ phase were analyzed using optical microscopy (OM), a ferritscope (FS), a X-ray diffractometer (XRD),
scanning electron microscopy (SEM), an electron probe micro-analyzer (EPMA), and a wavelength dispersive spectrometer (WDS),
respectively. Massive δ-ferrite was observed in the fusion zone of the first pass welds during welding of dissimilar stainless
steels. The σ phase precipitated at the inner δ-ferrite particles and decreased δ-ferrite content during the third pass welding.
The σ and δ phases can be stabilized by Si element, which promoted the phase transformation of σ→ϱ+λ2 in the fusion zone of the third pass welds. It was found that the σ phase was a Fe−Cr−Si intermetallic compound found in
the fusion zone of the third pass welds during multi-pass welding. 相似文献
77.
To ensure the core status can meet the requirements of thermal limits, stability and other constraints during the power ascension process of a nuclear power plant, operators usually gradually increase power based on onsite measurements and experience. To reduce the operator’s burden, this research develops a method to find an optimal power ascension path that can be followed by operators. The power ascension path is formulated as a multiobjective optimization problem with the following constraints: power ascension time, thermal limits, core stability and maximum rod line. A genetic algorithm is adopted to obtain the optimal power ascension path. The results show that using our approach full power can be achieved quickly, while maintaining reasonable margins of thermal limit and stability, in addition to satisfying maximum rod line criteria. 相似文献
78.
Kow Ming Chang Yuan Hung Chung Gin Ming Lin 《Electron Device Letters, IEEE》2002,23(5):255-257
Studies the anomalous variations of the OFF-state leakage current (IOFF) in n-channel poly-Si thin-film transistors (TFTs) under static stress. The dominant mechanisms for the anomalous IOFF can be attributed to (1) IOFF increases due to channel hot electrons trapping at the gate oxide/channel interface and silicon grain boundaries and (2) IOFF decreases due to hot holes accumulated/trapped near the channel/bottom oxide interface near the source region. Under the stress of high drain bias, serious impact ionization effect will occur to generate hot electrons and hot holes near the drain region. Some of holes will be injected into the gate oxide due to the vertical field (~(V_Gstress V_Dstress)/T OX) near the drain and the others will be migrated from drain to source along the channel due to lateral electric field (~V_Dstress/LCH) 相似文献
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Present-day power systems operate with high reliability, and it is rare that a blackout will extend over an entire system swiftly and securely. This paper considers automatic power supply to loads after a complete blackout of a system. First, taking into account characteristics of generators, loads, and initial power sources, a method is proposed of allocating several generators to each load in parallel to the system and supplying power to the load sequentially. Second, to remove the imbalance between supply and demand of power, a method is proposed of adjusting the amount of supply and generation according to a present imbalance and the sum of past ones. Third, to automatically issue orders for start-up, parallel, follow-up, stand-by, and stoppage of generators, several rules for each power station are set and an expert system is made based on them. Finally, the expert system is applied to a model power system, and it is verified that it can restore loads without any trouble for a complete blackout which occur at any time of a day and in any restoration pattern. 相似文献