A novel method for purification of recombinant adenoassociated virus vectors on a large scale

A novel method for recombinant adeno-associated virus (rAAV) purification on large scale is described. The method involves three steps, including chloroform treatment, PEG/NaCl precipitation and chloroform extraction. The whole procedure can be performed in four hours. Using this purification method, we can reproducibly obtain, from 4×10⁹ of proviral cells cultured in roller bottles, purified rAAV-GFP stocks with titers of around 5×10¹³ particles/mL and purity greater than 95%. The infectious titers of the vector stocks were up to 2×10 TU/mL, thus particle-to-infectivity rate was about 25. Under an electronic microscope, most rAAV particles appeared full and a few were in intermediate form. Empty particles were rarely seen. The purified rAAV-GFP stocks have been successfully used in in vitro and in vivo transfection experiments. Therefore, this new method offers a simple, rapid and cost-effective way for large-scale rAAV purification.     

Optimization of vertical well placement by using a hybrid particle swarm optimization

Locating wells is an important step in oil exploitation.This paper proposes a novel approach,which first combines particle swarm optimization,genetic algorithm,and a reservoir simulation evaluation tool to optimize the locations of vertical wells.Simulation results show that the convergence efficiency of our approach outperforms traditional genetic algorithm and overcomes the disadvantage of particle swarm algorithm that would be easily trapped into best-at-local solution so that its optimization result has been significantly improved.     

论政府官员微博的性质与功能

官员微博虽有“自媒体”的特性,但其传播本质上还是大众传播,要恪守大众传播的传播规范和传播伦理.官员微博对政务有间接影响,但没有政府正式认可或授权,其传播行为并不是行政行为,它不是政务微博,应当更多地从“虚”的或者“软”的角度来看它对政务的作用.因为官员身份和拥有政府资源,官员微博吸引了大批公众,从内容、风格、功能上,体现了公共性,不宜将它视为官员修身自娱的工具,应将其打造为“公共话语空间”,在公共生活中发挥积极作用.     

评孙奇逢“事已得凶仍使之趋吉”的《易》学思想

孙奇逢“独宗《十翼》”、特重“变通趋时”的 《易》 学思想， 不仅是唯物的、辩证的， 而且有着强烈的使命感， 其谓 “后天之 《易》 专为先天吉凶未露”的命题，就已准确地指明了这点； 尤其谓 “吉凶者以正而胜不论吉凶”的命题， 则给人生随时， 不惧刀山火海而堂堂正正做人， 指出了正确的方向。人生随时， 要前进， 就得“神理主中”，“因时而惕”， “悔吝在心”， 不仅要知“一念之善”而行之， 而且要知“一念之不善”而不复行之， 不断地“要尽人事以回造化”， 而推动社会的发展和前进。     

Ecological benefits of compound ridge culture in hillside orchard in the Three Gorge Reservoir Area

Based on contour tillage of wide ridge and furrow covering and agro-forestry, this paper sets up a compound ridge culture mode in hillside orchards and introduces a long-term observation to the mode＇s effects on ecological benefits of water and soil conservation. A five-year study shows that compound ridge culture in hillside orchards is effective in water and soil conservation, especially in reducing soil erosion. Compared with the traditional management modes of orchards, compound ridge culture has reduced runoff amount by 41.96%-57.96%, soil erosion amount by 55.47%-67.75%. Compound ridge culture also brings an obvious reduction of soil nutrient loss and of non-point source pollution, which is of great importance for keeping and increasing the productivity of hillside orchards in the Three Gorge Reservoir Area.     

试论人际关系与人际传播

本文论述了人际关系对人际传播内容和方向的决定性影响、由于这种关系而带来的人际传播中"装相"与"本相"的冲突。作者认为:人总是生活在具体的文化氛围中的,因而人际传播中会有一种无形的"文化契约,"决定着人际关系,并影响传播的内容、情感的表露,尽管传播双方或多方并没有实际签订什么契约,规则却是潜在的。     

光纤通信系统中光直接放大器的研究

随着光纤通信事业的迅速发展,人们对低噪声、高增益光直接放大器产生越来越浓厚的兴趣。本文将对半导体行波光放大器(TWA)、掺铒光纤放大器(EDFA)以及单片光电子集成光放大器等三种放大器的结构、机理、性能及应用作系统的论述。     

区域林业社会化服务体系建设的聚类分析

林权制度改革使得我国林业社会化服务体系的建设不断深入,因各区域经济发展和林业建设水平的差异,导致各区域林业社会化服务体系的建设呈现不同的特点。笔者选取了反映区域林业社会化服务体系支持水平、服务水平、经费投入3个指标因子,对14个省份和1个直辖市样本运用聚类分析的方法进行比较。结果表明：支持水平因子对各样本林业社会化服务体系影响最大,各区域林业社会化服务体系建设发展不平衡又各具优势。     

外部环境干扰下的非线性渔业资源种群动力模型及分析

运用欧拉方法获得离散的捕食者-食饵差分系统方程,并考虑添加一对捕食者的扰动项后建立了一外部环境干扰下的非线性渔业资源种群模型,从而定量分析正不动点的存在性、稳定性和局部分叉,发现系统可能产生Neimark分叉和倍周期分叉,用全局分析方法描述了资源在什么范围具有可持续性利用,即保持渔业资源种群数量不枯竭的资源储量范围.