异淀粉酶性质研究

以兰州市淀粉厂附近土壤中分离到的地衣状芽孢杆菌 (BacillusLicheniformis)为菌株 ,经过诱变选育出一株高产异淀粉酶菌株 ,并对其产生的异淀粉酶的性质进行了研究 ,结果表明酶作用的最适条件为 5 0℃ ,pH为 6 .8;在 5 0℃以下 ,pH 5 .0～ 8.0条件下较稳定 ;酶活性受Ca2 + 、Mg2 + 、Mn2 + 激活 ,Mn2 + 的激活作用较强 ,但受到Fe2 + 和Cu2 + 的严重抑制 .     

萌发玉米淀粉流变学特性的研究

实验研究了萌发玉米淀粉在不同温度和质量分数时剪切速率和表观黏度的关系,计算出各温度和质量分数下萌发玉米淀粉的稠度系数(K)和流变指数(n).实验表明,由于萌发玉米淀粉结构的微细化,淀粉糊表观黏度随温度的升高减小;质量分数增大时萌发玉米淀粉剪切稀化不明显.同时,温度的升高流变指数变化较大,偏向于牛顿流体;而质量分数的增加则使萌发玉米淀粉保持良好的假塑流体状态.     

青霉菌产漆酶条件及酶学性质的研究

通过对青霉菌产漆酶条件的优化,提高酶活,将其应用于生物制浆中。采用单因素对产酶条件进行研究,同时考察了漆酶的酶学性质。研究结果表明最佳培养条件为:麦麸16 g/L,酵母膏2 g/L,Al3+0.6 g/L,KH2PO43 g/L,30℃,pH 6.0摇瓶培养192 h。优化后漆酶的酶活提高了12.34倍。经过酶学性质的研究得出该酶的最适反应温度为30℃,而热稳定性为20~40℃,pH稳定性为3.6~4.0。     

皂荚豆组成及皂荚胶的流变性质

研究了皂荚豆的组成成分和皂荚胶的流变性质。结果表明:皂荚豆中蛋白质含量为15.38%,内胚乳占种子组成的37.8%;通过GC、PC、IR及HNMR分析多糖结构:内胚乳中含有68.6%的半乳甘露聚糖,半乳糖与甘露糖配比为1∶2.5,主链是以β (1,4) 苷键连接的D 吡喃甘露糖,支链是以α (1,6) 苷键连接的D 吡喃半乳糖;皂荚胶1%水溶液表观粘度达274mPa·s(30℃,170s-1),皂荚胶是高效的增稠剂;皂荚胶粘度随浓度升高而升高,随pH的降低而有所降低,皂荚胶水溶液为假塑性流体。     

松嫩平原小花碱茅无性系分蘖株数量特征的定量研究

通过对两生境小花碱茅独立分蘖丛的取样调查,定量地分析了松嫩平原小花碱茅无性系的数量特征。结果表明,打草地小花碱茅营养株数量是保护样地的1.33倍,保护样地生殖株数量、分蘖苗数量分别为打草样地的1.71倍、1.11倍,表明打草有利于营养生长。两样地小花碱茅无性系分蘖株数量、生物量与丛径之间均呈直线正相关系,其相关系数均达到了极显著水平(P<0.01)。     

热塑性丙烯酸树脂在快干涂料中的性能研究

探讨了热塑性丙烯酸树脂在快干涂料中对附着力和耐玷污性的影响因素,结果表明在加入改性树脂增强附着力时,582比EP2325的效果好;在选择涂料的溶剂时,要选用挥发速度适中、溶解度参数与树脂接近的溶剂,这样能得到较好的附着力;采用将BS-105与BS-1996混拼方法,利用彼此的优点去改善对方的不足,得到综合性能全面的涂膜;在保证涂膜使用性能的基础上,涂膜厚度小,对附着力有利。     

Bacterial adhesion and biofilms on surfaces

Bacterial adhesion has become a significant problem in industry and in the domicile,and much research has been done for deeper understanding of the processes involved.A generic biological model of bacterial adhesion and population growth called the bacterial biofilm growth cycle,has been described and modified many times.The biofilm growth cycle encompasses bacterial adhesion at all levels,starting with the initial physical attraction of bacteria to a substrate,and ending with the eventual liberation of cell dusters from the biofilm matrix.When describing bacterial adhesion one is simply describing one or more stages of biofilm development,neglecting the fact that the population may not reach maturity.This article provides an overview of bacterial adhesion.cites examples of how bac-terial adhesion affects industry and summarises methods and instrumentation used to improve our understanding of the adhesive prop-erties of bacteria.     

几丁糖预防椎板切除术后硬膜外瘢痕粘连及促进TGF形成的实验研究

目的 观察椎板切除术后用几丁糖预防硬膜外瘢痕粘连及椎板修复的效果。方法以20只日本大耳白兔为对象，随机分成A、B两组，制作L4椎板损伤模型，A组硬膜以生理盐水作为对照组，B组用几丁糖。术后12周进行大体观察、生化检查、TGF-β免疫组化染色检查：结果儿丁糖对预防硬膜外瘢痕粘连有明显的效果．且利于椎板缺损的修复。经Rydell-Balazs粘连韧度评分，硬膜外胶原含量测定及Nussbaum组织学评分，B组显著优于A组（P〈0．01）。结论几丁糖能有效预防硬膜外瘢痕粘连及使骨引导因子在局部浓集利于骨缺损的修复。     

自蔓延熔附成型陶瓷涂层的组织结构及性能分析

采用自蔓延熔附成型技术在普通碳素钢管内壁涂覆一层较为均匀致密的陶瓷层。对复合管的组织结构进行研究发现：陶瓷层呈枝晶结构特征，为复相结构，主晶相为α－Ａｌ２Ｏ３，还有ＦｅＡｌ２Ｏ４、ＺｒＳｉＯ４、ＺｒＯ２和Ｆｅ等相。陶瓷层其它相结构取 决于添加剂的种类。     

Loss of FrmA leads to increased cell-cell adhesion and impaired multi-cellular development of Dictyostelium cells

Cell-cell adhesion is a critical property of all multi-cellular organisms and its correct regulation is critical during development, differentiation, tissue building and maintenance, and many immune responses. The multi-talin-like FERM domain containing protein, FrmA, is required during starvation-induced multi-cellular development of Dictyostelium cells. Loss of FrmA leads to increased cell-cell adhesion and results in impaired multi-cellular development, slug migration and fruiting bodies. Further, mixing experiments show that FrmA null cells are excluded from the apex of wild-type mounds, to which cells that normally form the organising centre known as the tip sort. These data suggest a critical role for FrmA in regulating cell-cell adhesion, multi-cellular development and, in particular, the formation of the organising centre known as the tip. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Received 28 August 2008; received after revision 10 October 2008; accepted 21 October 2008