微生物法测定婴幼儿配方乳粉中的生物素、叶酸和VB12

目的:采用微生物法测定婴幼儿配方乳粉中生物素、叶酸和VB12.方法:利用不同乳酸菌对特定维生素具有敏感性的特点,通过测定菌株的生长变化来反映样品中相应微生物的维生素含量,对市售的13种婴幼儿配方乳粉维生素进行测定.结果:微生物法对于生物素和VB12测定数据更稳定,重复性好,生物素相对标准偏差为0.056％～4.158％,VB12的相对标准偏差范围为0.112％～3.848％,而叶酸的检测数据之间波动稍大,相对标准偏差为1.236％～8.332％.结论:本法适合婴幼儿配方乳粉中生物素、叶酸和VB12这3种维生素的分析定量研究.     

Training methodologies differ with the attachment of humans to horses

Our investigation is the first to use attachment theory to explore four commonplace training methods (Conspecific, Behavioral, Eclectic, and Conventional) and owners' levels of attachment (anxiety and avoidance) to their horses. An international sample of horse riders and handlers (N = 538), aged 18-80 years, completed demographics and the Experiences in Close Relationships—Relationship Structures Questionnaire. Behavioral training participants scored significantly higher on the attachment-avoidance scores to their horses than the Eclectic or Conspecific training methods. The Behavioral and Eclectic training methods were associated with higher levels of education. Further research is warranted to elucidate the role that training methods play in the relationships between humans and horses.     

野生动物价值评估方法的评价

野生动物不同于一般的商品,它是一种缺乏市场价格的“公共商品”。因此对野生动物价值的评估方法也不同于一般的经济学方法。本文根据国内外野生动物价值评估的研究现状,主要介绍了两种实用的野生动物价值评估方法即旅行费用法（TCM）和条件价值评估法（CVM）,并对这两种方法的优点及局限性进行了评价。     

Organic additives used in beef cattle feedlot: Effects on metabolic parameters and animal performance

Organic additives are recently being used in animal diets owing to their ability to control metabolic issues and result in better animal performance. Specifically, the organic additive Fator P^® presents an additional advantage that is to cause a lesser greenhouse gas emission. This study evaluated whether Fator P^® intake changes ruminal parameters or animal performance of beef cattle. Evaluations were carried out in a feedlot experiment divided into growing (46 days; two diets [control mix—CM and standard mix—SM] and finishing (lasted 83 days; four diets: CM, SM, Fator P^® + virginiamycin, and Fator P^® alone [FP]) trials. Animal performance study involved 48 animals allocated to 12 collective pens in completely randomized experimental design. Ruminal parameters were evaluated in separate metabolism study developed carried out using individual pen with four steers. During growing trial, FP diet resulted in higher (p < 0.05) dry matter intake (DMI) and ruminating time. In the finishing trial, diets containing Fator P^® resulted in higher DMI than obtained with CM. Most of the ruminal parameters did not differ (p > 0.05) among dietary treatments. Therefore, Fator P^® represents a viable and safe strategy for supplementation to beef cattle finished using high‐concentrate diet in feedlot systems.     

Analysis and experimental study on identification of inner force of steel tube under tension (compression) and bending using blind-hole method

为了解在役拉(压)弯钢管的内力情况,在盲孔法测量钢结构应力的基础上,提出了拉(压)弯钢管的内力识别方法.采用盲孔法对不同外径、不同荷载下的3组9根钢管试件进行了2种不同方式下的钻孔试验,研究了不同钻孔方式、不同外径、不同表面应力分布情况下的钻孔释放规律.试验结果表明:钻孔加工应变对测量精度影响较大,计算应力时应消除钻孔加工应变的影响;在应力超过f_y/2时需对释放系数进行塑性修正;钢管表面应力的测量精度随钢管直径的增大而提高.盲孔法用于拉(压)弯钢管的表面应力检测和杆件内力识别,无论理论上还是实际操作都是可行的,识别精度满足工程应用要求.     

3种半数致死浓度计算方法之比较

通过对寇氏法、概率单位法及线性回归法等3种半数致死浓度(50%lethal concentration,LC50)计算方法的阐述,比较了其基本公式与操作方法等。结果表明不同时间的半数致死浓度均依线性回归法、寇氏法、概率单位法的顺序逐步升高,但差异性不显著(P>0.05)。在操作上,概率单位法和线性回归较寇氏法更容易掌握。     

副溶血弧菌检测技术的研究进展

副溶血弧菌引发食物中毒的规模呈明显的上升趋势,目前已超过沙门氏菌食物中毒,跃居首位。因此需要从多方面加强检测,以防止该菌对食品造成的大面积污染,保证人的身体健康。为此本文全面介绍了副溶血弧菌的各种检测方法,包括:传统方法,免疫学方法,分子生物学技术,传感器技术等,为副溶血弧菌的检测提供理论依据。     

氟苯尼考PEG6000固体分散体的无溶剂熔融法制备与分析

采用无溶剂熔融法,对难溶性药物氟苯尼考的水溶性粉进行了研究。以聚乙二醇6000（PEG6000）为载体,制备氟苯尼考（florfenicol,FF）固体分散体,用X-射线衍射法、红外光谱法、电子显微镜扫描法和溶出速率法对固体分散体进行了表征,比较氟苯尼考原粉、氟苯尼考PEG6000固体分散体、氟苯尼考-PEG6000物理混合物的溶出速率,并用高效液相法测定固体分散体的溶解度。结果显示,氟苯尼考原粉、固体分散体和混合物的X-射线衍射图谱、红外光谱、电镜结果和溶出速率存在明显差异,氟苯尼考原粉是晶体态的片层结构,固体分散体则为无定形态,固体分散体的溶出速率高于氟苯尼考原粉和物理混合物,固体分散体的溶解度达到3．441mg／mL。无溶剂熔融法制备氟苯尼考PEG6000固体分散体可以提高氟苯尼考溶解度,且方法简单,易于推广。     

本科酶工程课程教学实践与体会

酶工程是高校生物工程和生物技术专业重要的专业课。结合课程教学实践,总结了酶工程教学过程中的几点体会,以提高酶工程教学质量,达到学生综合能力的培养目的。     

新疆不同地区牛源大肠杆菌耐药性分析

This study was aimed to investigate the resistance of Escherichia coli isolates from cattle farms in Xinjiang to antibiotics. The resistances of Escherichia coli isolates from cattle farms in five regions to commonly used antibiotic were determined using microdilution broth assay. Escherichia coli isolates were highly resistant to ampicillin (up to 39.3%) in all regions, and existed multidrug-resistant, but zero resistance was the dominant. Escherichia coli isolates from E cattle farm in Cherqi town, Baicheng county, exhibited resistant to three kinds of quinolones (6.7%). The results suggested that the resistances of Escherichia coli isolates to commonly used antibiotics were not serious in Xinjiang.