三丁基锡对黑腹果蝇（Drosophila melanogaster）的致死效应与生殖阻碍

[目的]研究三丁基锡（Tributyltin,TBT）化合物对黑腹果蝇（Drosophila melanogaster）的致死效应和生殖阻碍作用。[方法]先进行TBT对黑腹果蝇的半致死剂量测定．再利用初次产卵时间、产卵数量和孵化率指标衡量TBT的生殖阻碍作用。[结果]TBT对野生型黑腹果蝇的24h、48h、72h和96hLc50分别是441μM、270μM、220μM和191μM。随着TBT浓度的升高。野生型、残翅型和白眼型果蝇的初次产卵时间均呈现推延现象,并且产卵数量和孵化率也呈现递减趋势。[结论]黑腹果蝇对TBT具有高耐受力。TBT具有显著的生殖阻碍作用,必须禁止TBT的使用以降低生态危害。     

线性与波动——两种训练分期模式评析

线性传统训练分期模式为我国竞技体育的发展做出过重大贡献,非传统波动训练分期模式一段时间以来在西方国家较为流行。通过对两种训练分期模式进行回顾与分析后认为,非传统波动训练分期模式的引入,是对传统训练分期模式的有益补充和丰富。两种训练分期模式对科学、合理地安排运动训练过程都具有参考意义,并各有其适宜的范围和条件。     

篮球、蹦床运动员在辨别任务中的返回抑制时程特征

采用辨别任务形式比较运动员与普通大学生的返回抑制时程特征.实验为"3×2×3"的混合设计,组间变量为被试组别(篮球运动员、蹦床运动员和普通大学生各16人),组内变量依次为靶子位置(线索化位置和非线索化位置)和线索化开始到靶子出现的时间间隔(SOA,400、600、800 ms).结果发现:篮球运动员、蹦床运动员和普通大学生分别在SOA为400、800和600 ms开始出现返回抑制.说明与普通大学生相比,篮球运动员表现出较强的抑制效应,能在较短的SOA中出现返回抑制,而蹦床运动员没有表现出返回抑制能力的优势,需要在更长的SOA中才能出现返回抑制.返回抑制对篮球运动员的心理选材和训练监控、定向具有一定的参考价值.     

羧甲基纤维素对抑制滑石浮选的作用机理

研究了硫化矿和滑石浮选分离过程中羧甲基纤维素钠(CMC)的抑制机理,结果表明,CMC吸附在硫化矿表面主要是通过其中的羟基和羧基与硫化矿表面作用,羟基可以在硫化矿表面形成氢键,羧基能够与硫化矿发生静电作用和化学作用.硫化矿吸附CMC后,其表面负电性增强,疏水性减弱,同时CMC也会影响硫化矿捕收剂在硫化矿表面的吸附.     

大理单刺仙人掌提取物抑菌效果及抑菌机理的初步探讨

目的：探讨大理地区单刺仙人掌乙醇提取物和超声波提取物的体外抑菌效果及其抑菌机制。方法：以乙醇提取法和超声波提取法提取仙人掌原液,用K-B法分别测仙人掌提取物对标准株金黄色葡萄球菌、大肠埃希菌和白色念珠菌标准株的抑菌效果,以常量稀释法检测其最低抑菌浓度,并以抑菌曲线初步探讨其抑菌机制。结果：两种方法提取的仙人掌原液对实验菌株均有抑制作用,乙醇提取物的最低抑菌浓度小于超声波提取物。抑菌曲线表明,乙醇提取物原液在金黄色葡萄球菌生长的9 h内均表现出抑制作用。结论：大理地区的单刺仙人掌两种提取物对本实验的革兰阳性菌和革兰阴性菌及真菌均有抑制作用,其中乙醇提取物的抑菌效果较超声波提取物好。本研究可为仙人掌提取物的进一步研究和应用打下理论基础。     

H_2S对Q235钢在CO_2介质中的腐蚀影响及缓蚀研究

采用失重法研究了H2S对Q235钢在CO2介质中的腐蚀影响及咪唑啉缓蚀剂的缓蚀性能,并用电子探针分析了Q235钢表面的腐蚀产物膜,结果表明:常压CO2-H2S溶液中,H2S加速了CO2的腐蚀,在高压CO2-H2S溶液中,Q235钢腐蚀速率的对数lgRCO2-H2S与二氧化碳分压的对数lgPco2不成线性关系,实验室合成的咪唑啉化合物具有较好的缓蚀效果。     

Determination of Acid β-Galactosidase Activity: Methodology and Perspectives

Early, accurate diagnosis of lysosomal storage disorders is a major challenge, even for trained specialists. Finding innovative, accurate diagnostic methods, and high throughput, cost-effective tools are crucial to medical progress and will contribute to improved quality of life. The goal of this work was to improve currently used protocols to determine activity of acid β-galactosidase, and discuss the possibility analysing lysosomal enzymes with microfluidic systems. A principle of the determination of β-galactosidase activity was fluorometric measurement of a deprotonated form of 4-methylumbelliferone released in the enzymatic reaction. Measurements were performed using Jurkat T cells as a source of the enzyme. We observed the temperature-dependent substrate inhibition effect and determined the substrate (4-MU-β-d-galactopyranoside) concentration which should be used to determine acid β-galactosidase activity at 37 °C (0.8 mM) and at room temperature (0.6 mM). We proved that the sample incubation time may be significantly reduced to only a few minutes. We also showed that the amount of alkaline buffer used to stop the enzymatic reaction may be minimized and even, in some cases, eliminated. The presented results show how the sensitivity of the available methods to diagnose patients suffer from gangliosidosis GM1 or Morquio B disease can be improved. The proposed method may be easily implemented with microfluidic systems, which currently are promising tools for point-of-care applications.     

Hydrolysis of Raw Corn Starch Granules by Glucoamylase and Product Inhibition During the Hydrolysis

Raw corn starch granules were hydrolysized by glucoamylase in a chemostat. The hydrolysis of three different-sized granules shows that smaller granules undergo more hydrolyzation than larger ones. After 78 h, 97% of the granules was hydrolysized with diameter between 0.15 mm and 0.3 mm at 50℃. When corn starch concentration increased from 100 g/L to 250 g/L, the amount of reducing sugar produced was proportional to the initial substrate concentration and no substrate inhibition phenomenon appeared. In order to study the product inhibition exactly, the product from hydrolysis reaction itself was added into the hydrolysis system at the beginning of starch hydrolysis.Product inhibition with different quantities of product added were studied in the initial several hours,during which period enzyme inactivation could be neglected and product inhibition could be studied separately. The experiments indicate that product inhibition happens when the additional quantity exceeds 9.56 g/L.     

Interference and Inhibition in Cognition and Behavior: Unifying Themes for Educational Psychology

In this article, we review modern work on interference and inhibition in cognition and behavior. We begin by briefly reviewing the historical and conceptual roots of this new body of work. Next we discuss five new theoretical frameworks that use the concepts of interference and inhibition to explain cognitive and behavioral phenomena. In the section that follows, we review evidence of individual and developmental differences in inhibition and susceptibility to interference in at-risk students. We then consider the implications of this new body of work for research on educational psychology by discussing six selected areas of research: intelligence, strategies, reading comprehension, logical and mathematical reasoning, self-regulated learning, and retention. In the next section, we explore four critical issues that pose significant challenges to research in inhibition and interference. Finally, we discuss the relevance of this work to educational practice by focusing on its implications for the curriculum and instruction. Throughout, our principal goal is to bring this new body of work to the attention of the readers of this journal and to show how it might be useful in guiding research and theory in educational psychology.     

孔石莼水溶性抽提液抑制海洋浮游植物生长

研究了不同浓度和不同光照条件等处理下孔石莼水溶性抽提液对5种海洋浮游植物生长的影响,以揭示孔石莼泛滥,藻体死亡分解释放出的内含物对其周围环境中浮游植物类群所产生的生态影响。结果表明:孔石莼体内含有克藻物质,其对实验的五种藻类全部表现出抑制效应,不同强度光照处理对孔石莼体内抑藻物质的含量影响不明显。该抑藻物质不耐高温。