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991.
ZHANG Jie Yang Ke TAN DeYong ZENG JunYing Alan FINE 《科学通报(英文版)》2007,52(16):2210-2215
Constitutively expressed Fas ligand (FasL) in several distinct epithelial cell types appears to protect tissues by inducing apoptosis of Fas immune cells during inflammatory reactions. To study the rela-tionship of FasL and inflammation process in cornea,we examined the effects of inflammatory cytokine IL-1β on the FasL production,expression and cytotoxic function in corneal endothelial cells. In this paper,we demonstrate that IL-1β inhibits the FasL production and expression in corneal endothelial cells. The promoter activities of FasL in these cells are reduced by IL-1β in a dose-dependent manner. Finally,we also find that IL-1β block the cytotoxic effects of FasL derived from corneal endothelial cells to the Fas target cells. These data support the view that FasL derived from corneal endothelial cells modulate inflammation within cornea. 相似文献
992.
WU Song CHEN Hong GU JiaHua YU HongRut 《科学通报(英文版)》2007,52(17):2305-2309
This study deals with the sources of signal distortion of a piezoelectric transducer heated by measured gas flow. These signal distortions originate from both unloading of preload on a piezocrystal because of expansion of a diaphragm in the test apparatus and the pyroelectric effect of a heated piezoelectric crystal. A plastic film on the diaphragm of the transducer can effectively insulate the diaphragm and the piezocrystal within transducer from heating by gas flow, eliminating the sources of distortion. A method for evaluating the thickness of the film is proposed. 相似文献
993.
ZHAO DongMin ZHAO JiQuant ZHAO ShanShan HE LeQin WANG WeiYu 《科学通报(英文版)》2007,52(17):2337-2344
A secondary amino-modified mesoporous molecular sieve MCM-41 was obtained by reaction of bis(3-(triethoxysilyl)propyl)amine with MCM-41. The chiral Salen-Mn (III) complex was anchored onto the modified MCM-41 by a multi-step grafting method and two heterogenized catalysts with different Mn contents were obtained. The catalysts were characterized by XRD, N2 adsorption, ICP, FT-IR and DR UV-Vis. Their catalysis on asymmetric epoxidation of several olefins was studied with NaClO and m-CPBA as oxidants respectively. It was found that both the activity and enantioselectivity of the cata- lysts decreased after the homogeneous catalyst was heterogenized. The reasons resulting in the de- crease of catalytic performance were discussed. 相似文献
994.
Mechanism of the interaction between Au nanoparticles and polymerase in nanoparticle PCR 总被引:1,自引:0,他引:1
MI LiJuan ZHU HongPing ZHANG XiaoDong HU Jun FAN ChunHai 《科学通报(英文版)》2007,52(17):2345-2349
Nanoparticle PCR is a novel method to optimize DNA amplification. It performs well in improving specificity, enhancing sensitivity and speed. Several mechanisms were proposed in previous studies: one was based on the interaction between gold nanoparticles (AuNPs) and DNA while the other was attributed to the heat transfer property of AuNPs. In this paper, we propose that the interaction between AuNPs and DNA polymerase can significantly influence PCR. First, the addition of DNA polymerase can eliminate the inhibitory effects of excess AuNPs. Second, the addition of AuNPs will increase yield of the desired PCR product and make the optimum concentration of DNA polymerase move to higher value. Third, while excess polymerase might inhibit amplification efficiency, AuNPs can reverse this process and the yield of PCR amplification. Based on these results we propose a possible mechanism that AuNPs might modulate the activity of polymerase and improve PCR amplification. 相似文献
995.
数字化校园发展迅速,同时带来了海量的网络信息.本文针对校园信息传播及其监控的有效性问题,设计并实现了基于Web日志分析的校园网受众分析系统,通过挖掘Web日志中的相关数据并进行统计、分析、综合,得到了特定信息在特定时期内的传播范围及其用户分布情况,同时基于访问量特征提出了校园网信息的3种基本类型.本文还结合实际校园网的运行数据进行了实验和相应的分析,显示出所建立模型的合理性和有效性. 相似文献
996.
李星 《江西科技师范学院学报》2011,(5)
八一精神与井冈山精神、苏区精神、长征精神、延安精神一脉相承、同根同源,是中国共产党在领导中国革命斗争过程中形成的革命精神。它们之间既有共同之处,又存在不同点,本文拟通过八一精神与其他革命精神的比较研究,呼吁社会各界应更加关注八一精神,充分认识和把握八一精神在中国革命和建设中的历史地位和现实价值。 相似文献
997.
The graft modification of N, N'-methylene-bisacrylamide (NNMBAA) onto silk using eerie ammonium sulfate, potassium persulfate, ammonium persulfate and 2, 2-azobis (isobutyronitrile) as the initiators has been studied in the presence of air. To establish reaction conditions for the graft modification of NNMBAA onto silk, the effect of different variables such as the initiator concentration, monomer concentration, acetic acid concentration, time of polymerization, reaction temperature and liquor ratio (fabric: liq.) have been studied. The optimum grafting conditions were found. As evidence of grafting, analyses of amino acid composition and alkali solubility have been carried out. Grafting caused changes in amino acid composition and alkali solubility of silk. The observation has been explained in relation to structural changes in the grafted silk. 相似文献
998.
A new generation of cement, microbe cement, has been developed in response to the ever increasing awareness of environmental protection. Microbe cement is a new strengthening material based on microbiologically induced precipitation of calcium carbonate. This paper confirms the feasibility of binding loose sand particles using microbe cement and details the cementation mechanism of microbe cement. We have also prepared microbe cementitious materials (biosandstones). The compressive strength of the bio-sandstone, which depends on the content of calcium carbonate produced by microbially induced precipitation and the bio-mediated calcite crystal size, could be up to 12 MPa at an age of 20 days. By increasing the precipitated calcite content, the compressive strength and microstructure of bio-sandstone could be improved. 相似文献
999.
K-means clustering is arguably the most popular technique for partitioning data. Unfortunately, K-means suffers from the well-known
problem of locally optimal solutions. Furthermore, the final partition is dependent upon the initial configuration, making
the choice of starting partitions all the more important. This paper evaluates 12 procedures proposed in the literature and
provides recommendations for best practices. 相似文献
1000.
This paper presents a fast pseudorandom generation algorithm, which is based on the BLAKE hash function and can pass the random
test of the NIST (National Institute of Standards and Technology) Statistical Test Suite. Through theoretical analysis and
experimental imitation, our new algorithm is proven to be more secure and efficient than G-SHA1. Simultaneously, we introduce
and discuss the BLAKE in detail. Its security shows that can be utilized to generate pseudorandom bit sequences, which the
experimental results show the BLAKE hash function has excellent pseudorandomness. Therefore, we believe the BLAKE is one of
the most potential candidate algorithms of SHA-3 program. 相似文献