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991.
This paper analyzes the characteristics of super typhoons(STYs)over the western North Pacific(WNP)from 1965 to2005 and describes the seasonal variability of STY activity.The relation between STY activity and the El Nio-Southern Oscillation(ENSO)as well as the possible reason for the influence of the ENSO on STY activity are also investigated.The results showed thatabout one fifth of the tropical cyclones(TCs)over the WNP could reach the rank of STY.Most STYs appeared from July to Novem-ber while there was a highest ratio between number of STYs and total number of TCs in November.Most STYs appeared east of thePhilippine Sea.In El Nio years,affected by sea surface temperature(SST),monsoon trough and weak vertical wind shear,TC for-mation locations shifted eastward and there were more STYs than in La Nia years when the affecting factors changed. 相似文献
992.
A cell line,SHK,was derived from the kidney of spotted halibut Verasper variegates.The cell line was subcultured more than 40 passages in minimum essential medium(MEM)supplemented with fetal bovine serum(FBS)and 10 ng ml-1 basic fibroblast growth factor(bFGF).Cell morphology from primary culture and subculture was observed continuously by microscopy.The SHK cell line consisted predominantly of fibroblast-like cells.The cell line was able to grow between 20℃ and 30℃ with the optimum growth at 24℃ and with a reduced growth between 12℃ and 20℃.The growth rate of the cells increased as the proportion of FBS increased from 10% to 20% at 28℃ with optimum growth at the concentration of 20%.The doubling time of the cells was determined to be 44.8 h.Chromosome analysis revealed that 52% of the SHK cells maintained a normal diploid chromosome number (2n=46).The cells were successfully transfected with green fluorescent protein(GFP)reporter plasmids and the expression of GFP gene in the cells indicated the possible utility of the cells in gene expression studies.The cells were infected by lymphosystis disease virus(LCDV)and found to be susceptible to the virus in cytopathic effect(CPE)observation.The infection was confirmed by PCR and electron microscopy experiments,which proved the existence of the viral particles in the cytoplasm of the virus-infected cells. 相似文献
993.
"改造成矿作用"理论是中国科学院涂光炽院士提出的完善矿床成因分类学"四分法"的新理论,是中国学者对世界地球科学的重要贡献。该文根据会泽铅-锌(银、锗)矿床地质地球化学特征,列举其沉积改造的充分证据,用改造成矿的四大要素审视其矿床成因,认同它是典型而独特的沉积—强烈改造矿床,并以重要的宏观地质为依据,注意到峨眉山玄武岩(260 Ma)本身及昆阳群褶皱基底均未赋存一定规模的铅锌矿床,认为玄武岩与基底供给会泽铅锌矿(245~246 Ma)成矿物质有限,成岩与成矿时差太大,且成矿断层切割玄武岩,说明玄武岩成岩在先,铅、锌成矿在后,二者无直接成因联系。对会泽铅锌矿床的物质来源,有主张来自地层、基底、玄武岩或多来源者,但以何者为主,多种金属是否同源尚缺深入讨论,文章特别对地层、基底、峨眉山玄武岩中各成矿元素的含量、富集系数及富集类型进行系统的求算与分析研究,以讨论各种成矿金属的可能来源几率及其对成矿的贡献估计。结果显示:银在各地质体中均高倍富集,可提供充沛矿质,铅次之;锌则相反,多为正常元素或亏损元素,锗、镓、铟亦然,故矿石中的锌、锗、镓、铟,更可能为深部提供。结合大量的微量元素、稀土元素、铅、硫、锶、碳、氢、氧同位素等地球化学资料分析研究,认为地层,特别是震旦—寒武系、泥盆系、下石炭统摆佐组(C1b)与深部是主要的矿质来源,不同金属可同源或异源。矿床受地层岩性与构造的双重控制,与岩浆活动无关,具备改造成矿要素,属典型的沉积—强烈改造铅锌矿床,且具超大、特富、多金属富集的独特性。海西期下石炭统摆佐组已沉积成岩成矿或形成矿源层,后经印支期构造运动强烈改造而超常富集成矿,多掩盖其沉积特征,它属于沉积改造矿床"会泽式"。 相似文献
994.
PM_(2.5)降尘作用于A549细胞后,MTT法检测细胞存活率,扫描电镜观察细胞形态,流式细胞术检测细胞周期改变,RT-PCR检测周期阻滞相关基因p53、p21、CDK1、c-myc和lncRNA H19的表达水平,Western-blot检测周期蛋白cyclin B1表达。通过转染H19 siRNA干扰H19的表达,RT-PCR检测其对p53、c-myc及CDK1表达的影响,以探讨PM2.5降尘诱导A549细胞周期阻滞的作用机制。结果显示,PM2.5降尘暴露可降低A549细胞存活率,随作用浓度及时间增加呈递减趋势,并可观察到细胞形态破坏,细胞膜表面吸附聚集大量粉尘颗粒。PM2.5作用于细胞24 h后,A549细胞增殖阻滞在G2/M期,周期阻滞相关基因p53、p21及H19表达增加,CDK1及cyclin B1表达降低。此外,转染H19 siRNA后成功干扰H19的表达,并调控CDK1表达进一步降低。综合以上结果,PM2.5降尘处理A549细胞后可通过激活p53及p21活性,抑制CDK1和cyclin B1表达水平,诱导G2/M期阻滞从而抑制细胞增殖。短期暴露于PM2.5后,lncRNA H19在染毒细胞中可能发挥特异性癌基因的作用,通过与p53及c-myc结合参与调控细胞周期,干扰H19低表达使细胞G2/M期阻滞更加明显。 相似文献
995.
ZHUJie ZHANGXiumei GAOTianxiang 《中国海洋大学学报(英文版)》2005,4(2):145-151
Histological development of Japanese flounder Paralichthys olivaceus larval skin and ultrastructural difference of skin between reared normal and malpigmented Japanese flounder were studied with light microscopy (LM) and transmission electron microscopy (TEM). The results show that the skin develops slowly before the metamorphosis, while at the onset of metamorphosis, the skin develops quickly and becomes complete in structure till about 50d after being hatched. Ultrastructural observation on the normal and malpigmented skins shows that the iridophore and melanophore are adjacent to each other. Profile and structure of the two kinds of pigmcnt cells are more complete in the skin of normal ocular side than in the skin of pigmented blind side. The ultrastructure of typical chloride cell was observed in the skin of Japanese flounder larvae for the first time. 相似文献
996.
郝明珠 《CT理论与应用研究》2000,9(2):16-18
目的:探讨骨巨细胞瘤的影像学表现。资料与方法:对50例各种类型的骨巨细胞瘤的影像学表现进行了分析结果:骨巨细瘤的基本影像表现为:骨端偏心性膨胀骨质破坏,骨皮质薄而完整,骨嵴纤细呈网络状,无骨膜反应,溶骨型者,骨皮质中断,骨嵴减少或消失肿瘤边缘较模糊;恶变者,破坏区的骨干侧出现虫蚀状或筛孔样骨质破坏,有骨膜三角和生长迅速的软组织肿块。结论:骨巨细胞瘤的X线表现具有一定的特征。CT能显示骨巨细胞瘤的内部结构,腰骶部骨巨细胞瘤可显示突向盆腔和腹腔内的软组织块影。 相似文献
997.
李祚泳 《成都信息工程学院学报》1996,(3)
在确立了大气环境质量标准物元矩阵基础上,对物元分析法在大气环境单元质量评价和排序中的应用进行了探索。实例分析表明物元分析法用于环境单元质量评价和排序是有效的 相似文献
998.
M. W. J. Scourfield 《Astrophysics and Space Science》1995,230(1-2):457-469
An auroral substorm, unique in that it occurred at the relatively low latitude of SANAE, is described based on the full range of observational techniques at SANAE together with satellite data. Some features fit the generally accepted picture of substorms, others do not. From ground-based television imagery of Giant Undulations the temporal evolution of their dynamics is obtained and possible theories for their extistence examined. Super fast auroral waves, with speeds of up to 1200 km s–1, have been observed for the first time. Their characteristics can not, as yet, be accounted for by a single generation mechanism. The potential value of simultaneous recordings of aurorae by television and riometer is discussed 相似文献
999.
Epidermal cells of amphioxus at different developmental stages were investigated by electron microscopy and colloidal carbon
tracing experiments. Amphioxus epidermal cells showed different ultrastructural characteristics at larval and adult stages.
The epidermal cells at all larval stages studied (24–96 h) had numerous vesicles containing electron dense materials in their
apical cytoplasm. In tracing experiments, carbon particles were found in apical vesicles and interoellular spaces. Under scanning
electron microscope, many crater-like protrusions were observed on the surface of the cells. These results indicated that
amphioxus larval epidermal cells may be capable of endocytosis. The epidermal cells of 3-month and adult amphioxus were obviously
secretory ones characterized by well-developed peripheral filaments, a prominent Golgi apparatus and abundant apical secretory
vesicles. This study also showed that adult amphioxus body surface mucus contained lectin that could agglutinate human red
blood cells. The authors propose that the epidermal cells of amphioxus larva and adult may contribute to the immune defense
of the amimal by different means.
Project 3860811 supported by NSFC and study also supported by the Shandong Natural Science Foundation (Grant No. 92D1144). 相似文献
1000.
大的喷气沉积型矿床可能由穿过盆地沉积柱进入基底岩系的热水对流房排放到海底形成。热液对流模式已经取得多方面地质地球化学证据及流体动力学的定量检验。喷气成矿作用是在很长地质历史时期中广泛发育的一种重要成矿作用。大陆边缘断裂槽中的深囟水盆及相邻的碳酸盐台地上的沉陷洼地都是有利的成矿环境。 相似文献