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据美国“Science News”1992年12月19日和26日合刊1992年重要科技新闻概要专集报道,美国农业部的科学家正式宣布镍对植物的生长和繁殖都是极其重要而必不可少的。这是38年来第一次增加的植物必需矿质元素种类。 相似文献
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邢福谋 《上海生物医学工程》1984,(1)
本文论述镍钛合金的制造加工及其与加工和热处理相关的特性,并详细论述它在医学上应用的可能性,如接骨板、骨髓钉、下颌骨合成材料和矫正脊柱侧弯材料的模拟实验。 相似文献
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镍是一个广泛分布的元素,土壤中含有10~1,000ppm,平均40ppm。苏格兰某些田间作物曾因受镍毒而不能生长,由蛇纹石发育的土壤含有很高的镍,往往使作物中毒,但在这种土壤上生长的野生植物多是含镍高的和耐镍的。 相似文献
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目的:研究不同浓度的镍对体外培养人脐静脉内皮细胞(HUVEC)的影响。方法:用两种镍化合物(NiCl2·6H2O、NiSO4·6H2O)分别制成含Ni(Ⅱ)浓度为1000、500、250、125、62.5μmol/L及31.25μmol/L的溶液,作用于体外培养的HUVEC细胞株,72h后MTT法测试细胞增殖活性,确定NiCl2·6H2O与NiSO4·6H2O的TC50,并分别以TC50的Ni(Ⅱ)作用培养的HUVEC细胞株,MTT法检测不同时间点(24h、48h、72h、96h、120h)的细胞相对增殖活性;2,4-二硝基苯肼法检测作用72h时培养上清液及细胞裂解液中乳酸脱氢酶(LDH)的含量,计算Ni(Ⅱ)化合物作用下细胞LDH的释放率,评价Ni(Ⅱ)对其影响;HE常规染色观察两种镍化合物作用72h后的细胞形态;AnnexinV-FITC/PI双标记流式细胞仪检测细胞凋亡。结果:两种化合物作用HUVEC细胞TC50为125μmol/L,随着浓度的不断增加,细胞毒性增强;同一浓度的Ni(Ⅱ)对细胞活性的影响随着作用时间增加而增强;两种镍化合物对细胞LDH释放率的影响无明显差异(P>0.05);NiSO4·6... 相似文献
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镍在植物生命活动中的作用 总被引:33,自引:0,他引:33
FunctionsofNickelinPlantsFUHul-Hua,WANGYu,TIANGTing-Liang(许你MofBmp,CedndChaaN~U。。…,Who430070)提要介绍了镍在植物生命活动中的作用以及植物对镍的吸收、运输与分布的研究情况,并对这一问题的研究前景作了一些分析。自从1855年Forchhamer”喀次发现植物中存在镍以来,人们对镍在植物中的作用进行了许多研究。70年代已经明确,镍是某些低等植物,如细菌、蓝藻和绿藻的必需微量元素。l,5,33]。DIX00“’‘报道了高等植物中第,个含镍酶——刀豆脱酶。脉酶专一性地分解肥,在植物氮代谢中具有重要功能,从… 相似文献
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Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis
It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis. 相似文献
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RICHARD E. NORRIS 《Botanical journal of the Linnean Society. Linnean Society of London》1991,106(1):1-40
Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera. 相似文献
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JOAN VALUÈS MONTSERRAT TORRELL NÚRIA GARCIA JACAS 《Botanical journal of the Linnean Society. Linnean Society of London》2001,137(4):399-407
Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted. 相似文献
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肝癌中HBV和HCV基因和抗原的分布及意义 总被引:1,自引:0,他引:1
采用原位分子杂交方法检测HCV
RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV
RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV
RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV
X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV
C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细 相似文献
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H.-R. GREGORIUS 《Biological journal of the Linnean Society. Linnean Society of London》1984,23(2-3):157-165
For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment. 相似文献
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment. 相似文献