两种木材中综纤维素的快速分离

采用微波辅助的方法实现木材综纤维素的快速分离的实验结果表明，微波辅助法在阔叶材水曲柳和针叶材落叶松心材的木素脱除方面表现出快速、高效，且对于水曲柳的效果好于落叶松。通过对所制得木材综纤维素中木素含量的测定、α-纤维素含量的测定、傅立叶红外光谱(FTIR)分析以及X-射线衍射的分析，初步证明了微波作用与传统方法分离得到的木材综纤维素差别不大，前者结晶度略高。     

Mechanism of mercerization revealed by X-ray diffraction

We studied the crystalline conversion of cellulose fiber from cellulose I to cellulose II (mercerization) by X-ray diffraction, focusing on the putative chain-polarity conversion from parallel to antiparallel. The structural change of Na-cellulose was examined during stepwise changes in NaOH concentration. Either Na-cellulose I or Na-cellulose II was formed depending on the initial NaOH concentration. Once formed, both structures were stable and did not inter-convert to each other when the NaOH concentration was changed. Such stability indicates that the parallel-to-antiparallel conversion is not likely to take place in the crystalline region of Na-cellulose. Regeneration of cellulose II from both forms of alkali cellulose proceeded with the formation of 0.44 nm lattice plane corresponding to the sheet of (1 ¯1 0) plane of cellulose II, showing that the molecular stacking due to van der Waals' interaction is the driving force of the formation of cellulose II. A mechanism was proposed whereby the geometry of the cellulose molecule allows close fitting of the hydrophobic faces only in the antiparallel arrangement, thus driving formation of the antiparallel structure of cellulose II.This study was presented in part at the 47th Annual Meeting of the Japan Wood Research Society, Kochi, April 1997; and at the 6th Annual Meeting of the Cellulose Society of Japan, Tokyo, June 1999     

网络环境下科技报告的检索

科技报告是一种重要的信息源,经常查阅可以提高科研水平的起点,因此提供了网络环境下国内外主要科技报告的检索途径和方法,包括一些网上科技报告免费检索的网站。     

Influence of milk components in establishing biofilm mediated bacterial mastitis infections in cattle: A fractional factorial approach

Biofilm formation is one of the factors responsible for antibiotic resistance. The involvement of biofilm formation in bacterial mastitis is well known. Milk composition varies during the lactation period and certain pathogens are producing more number of mastitis cases during particular periods of lactation. The present study elucidates the effects of different milk components on biofilm formation and the persistence of infection. The Plackett Burman screening design has been chosen for assessing the significance. Biofilm production of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were assessed by crystal violet assay. Dipotassium hydrogen phosphate had a significant effect on biofilm formation by S. aureus (MTCC 1430) whereas it was pH in the case of biofilm formation by P. aeruginosa (NCIM 5029). Other independent factors were found to be insignificant.     

花生红枣复合发酵功能饮料的研制

以花生仁、红枣、冰糖为原料,将花生仁、红枣分别制成花生浆和枣浆后按一定比例混合成“混浆”,加入冰糖溶解混匀,接种经驯化的乳酸混合菌进行乳酸发酵,由正交试验筛选出混浆发酵的冰糖添加量、接种量、发酵温度及花生浆∶枣浆值,制成具有独特的营养与保健功能且风味诱人的饮料。     

我国竹资源综合开发利用的现状分析

运用文献计量的方法,对我国1981～1990年的竹类研究文献进行了统计分析。近10a来文献量演变表明:竹资源综合开发利用(包括对竹子的利用和对竹林环境的利用)已成为近几年最为突出的重点和热点,竹资源综合开发利用各个方面呈现不平衡,其中竹产品加工和竹材人造板的文献量之和占竹资源综合开发利用总文献量的50％,是近年竹资源开发利用的主要内容。文中就8个方面论述了我国竹资源综合开发利用的现状、途径和发展动态,提出了搞好竹资源综合开发利用的几点看法。     

An assessment of the behaviors of overwintering manatees as influenced by interactions with tourists at two sites in central Florida

We used a combination of focal animal and scan samples over the course of two winter seasons to assess behavioral patterns of manatees as a function of the presence and activities of recreational swimmers and boats in and around Crystal River National Wildlife Refuge, Florida. The nature and outcome of human-manatee interactions and the frequency of harassment of manatees by swimmers (as defined by the US Fish and Wildlife Service) were also recorded. The use of protected (no-entry) sanctuaries by manatees was significantly greater when both the numbers of swimmers and boats increased, and when water temperatures were lower in surrounding areas. The time manatees spent bottom-resting and nursing decreased while the time spent milling and swimming increased when swimmers were present compared with when they were absent. Over half of the direct interactions recorded between swimmers and manatees constituted some form of harassment as defined by Refuge guidelines, and manatees were far more likely to terminate these interactions than were swimmers. We conclude that the existence of no-entry sanctuaries is very important for the conservation of manatees in the area and thought must be given to expanding the sanctuary network. Furthermore, additional efforts at enforcement and public education are needed. We address, qualitatively, several potential management options to better-secure manatees at this critical time of the year.     

无臭水晶大蒜温浸液循环使用工艺在生产实际中的应用

在实际生产中,通过对大蒜浸泡液成分改变及温浸温度和温浸时间的研究,确立了无臭水晶大蒜温浸液循环生产工艺为:水∶蒜米为1.5∶1,柠檬酸含量为水质量的2.4%,硫代硫酸钠含量为水质量的0.5%,第1次循环液添加10%硫代硫酸钠或20%柠檬酸,第2次循环液中需在首次添加基础上再添加40%的硫代硫酸钠和40%柠檬酸,3次以上循环液使用时,需采用50￣60℃逐渐升温的方法浸泡。     

东方栓孔菌在染料脱色中的应用及其脱色条件的优化

本研究利用东方栓孔菌（Trametes orientalis）菌株Cui6300发酵所得的粗酶液,对刚果红、结晶紫、铬天青、亚甲基蓝和中性红5种染料进行了催化脱色试验,并对其中脱色效果较好的染料进行了脱色条件优化。结果表明：东方栓孔菌漆酶粗酶液对结晶紫有相对较好的脱色效果。添加2,2＇-连氮-双（3-乙基苯并噻唑-6-磺酸）（ABTS）的粗酶液对结晶紫的降解效果没有明显促进作用,因此后续试验中直接采用粗酶液。脱色条件优化结果为：最佳初始pH值6.0,最佳培养温度55℃,最佳接种量2.0%,最佳转速160r/min,最佳底物浓度160mg/L。在此条件下反应96h,脱色率可达98.45%。本试验说明东方栓孔菌在印染废水治理方面具有较好的应用前景,可以作为一种新型菌株应用于染料脱色。     

基于晶体蛋白氨基酸组成的主成分分析识别其杀小菜蛾活性

基于晶体蛋白氨基酸组成的主成分分析(principal component analysis,PCA),构建杀虫晶体蛋白对小菜蛾杀虫活性的预测模型,用于晶体蛋白对小菜蛾有杀虫活性预测的正确率为76%,用于晶体蛋白对小菜蛾无杀虫活性预测的正确率为80%。该模型可作为一种实验开始前的预测方法,为筛选对小菜蛾有效的杀虫晶体蛋白提供参考,以提高筛选效率。