红豆杉中紫杉醇抗癌机理及获得研究

红豆杉属于世界濒危物种，而红豆杉的提取物紫杉醇具有独特的抗癌作用．综述了紫杉醇的抗癌机理和人类获得紫杉醇的方法．为解决紫杉醇的长期供应问题，国内外学者在紫杉醇人工获得方面进行了许多有意义的探索，为红豆杉野生资源的保护提供了有效途径．     

荒谬的红豆杉开发热

近来,我国南方不少地方掀起了一股“红豆杉热”。一时间,红豆杉茶、红豆杉酒、红豆杉饮料,以及各种红豆杉产品,层出不穷。起因是红豆杉树皮中含有一种抗癌物质——紫杉醇。然而,紫杉醇根本不溶于水。紫杉醇必须在化学溶剂作用下才能萃取,靠开水或酒类浸泡完全无效。对紫杉醇的研究最早始于美国。1989年,美国科学家将从红豆杉树皮中提取出来的紫杉醇应用于临床实验,结果表明紫杉醇对癌症有明显疗效,特别是对乳     

东北红豆杉中紫杉醇的含量分析

以抗癌活性成分紫杉醇作为标准物,利用高压液相色谱法分析了东北红豆杉树叶和树干的水提取物中抗癌活性成分紫杉醇的含量,确定最佳色谱条件为:色谱柱:C18,Φ4.6×250 mm;流动相:甲醇︰水︰乙腈=45︰35︰20;检测波长:225 nm;柱温:室温;流速:1.0 mL/min。结果表明:东北红豆杉树干中紫杉醇含量高于树叶。     

两种红豆杉离体细胞中紫杉醇含量的调节

以矮壮素、水杨酸和甘露醇为诱发子,研究了短叶红豆杉(Taxus brevifolia)和墨西哥红豆杉(Taxus globosa)离体细胞中紫杉醇含量的变化.实验结果表明:矮壮素、水杨酸和甘露醇不同程度地提高离体细胞中紫杉醇含量.短叶红豆杉的紫杉醇含量比墨西哥红豆杉的高,但诱发子诱导墨西哥红豆杉紫杉醇相对增加量大.0.5 mg*L-1水杨酸和0.5 mg·L-1矮壮素分别使短叶红豆杉和墨西哥红豆杉细胞中紫杉醇含量达到最高,分别是对照的1.8和15倍.还讨论了紫杉醇含量与愈伤组织生长的关系.     

红豆杉资源研究和开发现状

本文从红豆杉的生物学和生态学特征，野生资源现状，植物组织培养，紫杉醇的提取，纯化和抗癌临床试验等方面，系统介绍了红豆杉属植物资源的研究和开发进展状况。     

河南省曼地亚红豆杉发展现状及前景

曼地亚红豆杉具有净化空气,吸收空气中苯、甲苯等有害物质的作用,以其枝叶、树皮为主要原料提取的紫杉醇,是国际公认的抗癌良药。通过技术创新,加强对曼地亚红豆杉的人工培植与开发利用。     

利用生物技术生产紫杉醇研究进展

紫杉醇是红豆杉属植物中含有的一种二萜类拟生物碱复化合物,具有独物的抗癌作用机理。     

几种激素对东北红豆杉插穗扦插造林质量的影响

东北红豆杉是国家一级保护植物,第三纪孑遗物种,所含紫杉醇具有抗癌作用.本项研究对东北红豆杉在林内采用近自然扦插造林技术培育东北红豆杉药用林获得成功.研究结果表明:东北红豆杉扦插造林前应对插穗用ABT1号生根粉50～100 mg·L-1水溶液浸泡0.5 h或用IBA10～20 mg·L-1水溶液浸泡0.5~1.0 h,有利于生根和提高成活率,促进扦插苗的生长.     

南方红豆杉扦插育苗技术

景德镇市南方红豆杉(1株优树)紫杉醇含量达0.616‰,经查新为全国各地红豆杉紫杉醇含量最高,说明景德镇市具有紫杉醇含量高的优良类型.简述了景德镇具备发展南方红豆杉有利条件,并对该南方红豆杉优良母树进行扦插繁育试验,得出以清水沙为扦插(最佳)基质;11月下旬为扦插最佳时期.     

红豆杉细胞培养生产紫杉醇的研究进展

综述了近年来红豆杉细胞培养生产紫杉醇的研究进展, 包括红豆杉细胞培养生产紫杉醇的代谢调节、无机盐、植物生长调节因子、糖分及其它因素对红豆杉细胞生长和紫杉醇生产的影响等.着重介绍了前体饲喂、添加抑制剂和添加诱导子对红豆杉细胞生长及紫杉醇生产的影响.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

Features of Women''s language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme