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Type Ⅰ,Ⅲ and Ⅴ collagens were extracted from bovine dermis and cornea by using pepsin treatment in acetic acid solution,followed by salt precipitation and dialysis,to purify and isolate each type of collagens.The preparation process was analyzed by using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).A reducing agent,2-mercaptoethanol,was used to remove disulfide bonds and analyze the structure of the bonds involved between α chains in some types of collagens.The use of delayed reducing methods resulted in the difference between α1(Ⅲ) and α1(Ⅰ) chains in a mixture containing type Ⅰ and Ⅲ collagens.The structure of disulfide bonds among α chains exists potentially in type Ⅴ collagen prepared from the pepsin-treatment extraction at 4℃,which differs from type Ⅲ collagen in relation to the locations of disulfide bonds.Compared with pepsin-treated collagen at 4℃,the relative molecular weights of α1(Ⅴ) and α2(Ⅴ) chains treated at room temperature decrease by 4.6% and 6.0%,respectively.It is concluded that type Ⅰ,Ⅲ and Ⅴ collagens can be prepared from bovine dermis and cornea by the use of pepsin treatment,salt precipitation and dialysis.The interchain disulfide bonds lie potentially near the edges of termini of type Ⅴ collagen molecules in extracellular matrix,and a small number of interchain crosslinks exist in type Ⅴ collagen. 相似文献
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fixation rate and color fastness,but the Lanasol type of wool fiber used reactive dye is not so applicable to dye the soybean protein fiber.0针织工业Knittin 相似文献
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康琪 《中学英语园地(高三版)》2006,(4)
Showing a tourgroup around a m useum,the guide said,“Thatfossilin the glass case is two m illion and nine years old.”“H ow can you date itso precisely?”som eone asked adm iringly.“Thats easy,”replied the guide.“Ive been working here nineyears,and itwas two m illion years old when Icam e.”Two Million and and Nine Years Old$河南大学附中@康琪… 相似文献
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吕蔷 《高等教育与学术研究》2006,(2)
Introduction Our most developed and established system of communication is, of course, language. But what we mean by language is a widely recognized problem and the term 'language' has been applied figuratively to all forms of human behaviour. What is clear is that what- ever language may be, it is communicative, and it is not the only system of communication, nor is it the on- ly instrument of human communication, just the most subtle and powerful. Since the last half century, the notion of '… 相似文献
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《International Journal of Educational Research》1998,29(2):95-105
The purpose of this chapter is to offer reflections on integration research. A plea is made for a more precise and careful use of the concept “integration” and, above all, a more careful and critical interpretation of results from studies and experiences of so-called integration endeavors. Some serious misunderstandings that result from an incorrect or imprecise use of integration are pointed out. Critical distinctions between integration and inclusion are made. Results from a longitudinal study in Sweden are summarized. 相似文献
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人物：N—Narrator P—Pig R—Rabbit
道具：角色头饰，各种蔬菜及种子剪贴图
N：一天，小猪和小兔决定种自己喜欢的蔬菜。 相似文献
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南水北调中线工程水源区主要在十堰市,其水源区水质和水量基本达到调水要求,但水土流失、水体污染、移民安置、贫困与落后等问题影响工程效益,因此要保证＂一库清水向北流＂,关键是确保水源区水资源环境保护与可持续发展.针对十堰市的水资源环境情况,论述水资源环境与可持续发展的相关性,分析水资源环境存在主要问题的原因,提出了水资源环境与可持续发展对策. 相似文献
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Studies on the changes of West Lake's zoobenthic communites after Qiantang River water was pumped into it 总被引：3，自引：0，他引：3
During Jan. 1995 to Dec. 1996, monthly investigations on the zoobenthic communities of West Lake, samples were collected from
six sampling stations. A total of 26 species of macrozoobenthos were identified. The seasonal changes in density and biomass
of zoobenthos in this lake were analyzed. The annual mean densities were 980∼2751 ind/m2 and mean biomass was 19.69–122.80 g/m2. The densities in winter and early spring were higher than those in summer and autumn. Comparative study of theprevious data
(1982 to 1983) collected by the authors, showed that the succession of zoobenthic communities, dominated byProcludius choreus in density andBellamya purificata in biomass, had been occurred in Xiaonan sub-lake after Qiantang River water was drawn into it; and that the species and
biomass of zoobenthos were then increased and the density was decreased. In other sub-lakes, the dominant species wereLimnodrilus hoffmeisteri andTokunagayusurika akamusi in density andBranchiura sowerbyi andTokunagayusurika akamusi in biomass. The water quality was bad in these sub-lakes because these dominant species are indicators of eutrophication.
According to the Margalef index and Goodnight index, West Lake is still an eutrophic lake. Only the water quality of Xiaonan
sub-lake was improved after water drawn from the Qiantang River was introduced into it.
Project supported by the Evironmental Protection Bureau of Hangzhou, China. 相似文献
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遵循《水利建设项目经济评价规范》（ＳＬ７２-９４）及《水土保持综合治理效益计算方法》（ＧＢ／Ｔ１５７７４─１９９５）,以铁瓦河小流域水土保持工程为例,研究水土保持直接经济效益计算方法,得出的结果符合铁瓦河小流域实际情况,与一般规律是相吻合的,表明铁瓦河小流域的直接经济效益是显著的。 相似文献
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A laboratory incubation experiment was conducted to study the effect of copper as cupric sulfate (CuSO4.5H2O), and lead as lead acetate (Pb (OAc)2) on the size of the microbial biomass in red soil. The metals were applied, separately at six different levels: Cu at 50,
100, 200, 300, 400, and 600 μg·g−1 soil and Pb at 100, 200, 400, 600, 800, and 1000 μg·g−1 soil. In comparison to uncontaminated soil, the microbial biomass carbon (Cmic) and biomass nitrogen (Nmic) decreased sharply in soils contaminated with Cu and Pb. The microbial biomass C:N ratio in the metal contaminated soil was
observed to be considerably higher than that in untreated control. Between the two tested metals, Cu displayed greater biocidal
effect on microbial biomass carbon and nitrogen than Pb, showing their relative toxicity in the order: Cu≫Pb.
Project (No. 49671050) supported by National Natural Science Foundation of China.
Wa’el Mohamad—Former Ph. D. Student of Zhejiang University and is working in Ministry Of Agriculture (P. O. box. 2099), Amman,
Jordan. 相似文献
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南水北调中线水源区文化资源整合的经济运作 总被引：1，自引：1，他引：0
在概述南水北调中线水源区文化资源的基础上,探讨了发展南水北调中线水源区文化产业的必要性,进一步提出南水北调中线水源区文化资源整合的经济运作对策,一是构建跨行政区域的经济文化战略协作组织,二是塑造＂南水北调中线水源区文化＂品牌,三是通力打造中线工程水源区文化产业链. 相似文献
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Zhao XZ Wang GX Shen ZX Zhang H Qiu MQ 《Journal of Zhejiang University. Science. B》2006,7(4):283-290
Forest plays very important roles in global system with about 35% land area producing about 70% of total land net production. It is important to consider both elevated CO2 concentrations and different soil moisture when the possible effects of elevated CO2 concentration on trees are assessed. In this study, we grew Cinnamomum camphora seedlings under two CO2 concentrations （350 μmol/mol and 500μmnol/mol） and three soil moisture levels [80%, 60% and 40% FWC （field water capacity）] to focus on the effects of exposure of trees to elevated CO2 on underground and aboveground plant growth, and its dependence on soil moisture. The results indicated that high CO2 concentration has no significant effects on shoot height but significantly impacts shoot weight and ratio of shoot weight to height under three soil moisture levels. The response of root growth to CO2 enrichment is just reversed, there are obvious effects on root length growth, but no effects on root weight growth and ratio of root weight to length. The CO2 enrichment decreased 20.42%, 32.78%, 20.59% of weight ratio of root to shoot under 40%, 60% and 80% FWC soil water conditions, respectively. And elevated CO2 concentration significantly increased the water content in aboveground and underground parts. Then we concluded that high CO2 concentration favours more tree aboveground biomass growth than underground biomass growth under favorable soil water conditions. And CO2 enrichment enhanced lateral growth of shoot and vertical growth of root. The responses of plants to elevated CO2 depend on soil water availability, and plants may benefit more from CO2 enrichment with sufficient water supply. 相似文献
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Mahmood Q Siddiqi MR Islam Eu Azim MR Zheng P Hayat Y 《Journal of Zhejiang University. Science. B》2005,6(10):991-998
Water hyacinth (Eichhornia crassipes (Mart.) Solms) is a prolific free floating aquatic macrohpyte found in tropical and subtropical parts of the earth. The effects
of pollutants from textile wastewater on the anatomy of the plant were studied. Water hyacinth exhibits hydrophytic adaptations
which include reduced epidermis cells lacking cuticle in most cases, presence of large air spaces (7∼50 μm), reduced vascular
tissue and absorbing structures. Textile waste significantly affected the size of root cells. The presence of raphide crystals
was noted in parenchyma cells of various organs in treated plants.
Project (No. 30070017) supported by the National Natural Science Foundation of China 相似文献
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土壤、水、大气是环境的三大要素,是人类赖以生存的资源基础.但近年来,随着工业化、城市化进程的加快,环境污染形势日益严峻,土壤污染、水污染、大气污染事件层出不穷,环境污染治理时不我待.相比于水、大气污染防治,土壤污染防治尚无专门的法律规制.2014年4月24日,“史上最严环保法”出台,其在立法目的、环境监管、环境影响评价、环境信息公开、法律责任等制度方面推陈出新,为土壤污染防治法提供制订蓝本. 相似文献