Quality of bull spermatozoa after preparation by single-layer centrifugation

The present study aimed to evaluate the effect of single-layer centrifugation (SLC) through a species-specific colloid (Androcoll-B; patent pending, J. M. Morrell) on bull sperm quality. Computer-assisted sperm analysis of motility and flow cytometric analysis of sperm viability (SYBR-14/propidium iodide staining), chromatin integrity (acridine orange staining), reactive oxygen species production [Hoechst 33258-hydroethidine-2′,7′-dichlorodihydrofluorescein diacetate (HO-HE-DCFDA) staining], mitochondrial membrane potential (staining with JC-1 probe), and protein tyrosine phosphorylation (specific antibody staining) were performed on unselected and SLC-selected sperm samples. Single-layer centrifugation of bull spermatozoa resulted in the selection of a sperm population that had high mitochondrial membrane potential, a higher content of phosphorylated protein, and more reactive oxygen species than control samples. Sperm chromatin damage was lower in the SLC samples although sperm viability and motility did not differ between SLC samples and controls. These observations suggest that SLC of bull semen in a soybean-containing extender improved some, but not all, parameters of sperm quality.     

Enumeration of clostridia in goat milk using an optimized membrane filtration technique

A membrane filtration technique developed for counting butyric acid bacteria in cow milk was further developed for analysis of goat milk. Reduction of the sample volume, prolongation of incubation time after addition of proteolytic enzyme and detergent, and a novel step of ultrasonic treatment during incubation allowed filtration of goat milk even in the case of somatic cell counts (SCC) exceeding 10⁶/mL. However, filterability was impaired in milk from goats in late lactation. In total, spore counts were assessed in 329 farm bulk goat milk samples. Membrane filtration technique counts were lower than numbers revealed by the classic most probable number technique. Thus, method-specific thresholds for milk to evaluate the risk of late blowing have to be set. As expected, the spore counts of milk samples from suppliers not feeding silage were significantly lower than the spore counts of milk samples from suppliers using silage feeds. Not only were counts different, the clostridial spore population also varied significantly. By using 16S rRNA gene PCR and gene sequencing, 342 strains from 15 clostridial species were identified. The most common Clostridium species were Clostridium tyrobutyricum (40.4%), Clostridium sporogenes (38.3%), Clostridium bifermentans (7.6%), and Clostridium perfringens (5.3%). The 2 most frequently occurring species C. tyrobutyricum and C. sporogenes accounted for 84.7% of the isolates derived from samples of suppliers feeding silage (n = 288). In contrast, in samples from suppliers without silage feeding (n = 55), these species were detected in only 45.5% of the isolates.     

丝光淡碱废水对管式超滤膜污染的研究

通过扫描电子显微镜(SEM)和原子力显微镜(AFM)对纯化丝光淡碱废水的超滤膜表面污染情况进行形貌分析,膜面污染物主要以膜表面沉积的形式存在.通过EDS能谱仪和傅里叶红外光谱仪对膜表面污染物进行检测,膜面污染物成分主要为含有各种官能团的有机成分.用0.2％的磷酸和硝酸混合液与0.1％的十二烷基苯磺酸钠(SDBS)配制清...     

一锅法制备纳米纤维素及其性能研究

采用一种操作简单、绿色环保的以对甲苯磺酸为催化剂对竹纤维进行水热处理制备纳米纤维素(NCC)的方法.考察了反应时间、反应温度和超声作用对纳米纤维素得率和性能的影响.结果 表明,在反应温度110℃、反应时间45 min、超声时间120 min的条件下,纳米纤维素得率最高.     

高蛋白饮用型长保质期酸奶产品的研究

对高蛋白酸奶的加工方法及稳定体系和工艺进行了研究。通过添加乳清蛋白和膜浓缩2种不同方式提高产品蛋白含量;通过稳定性观察、感官测试和稳定性检测综合评价产品稳定体系。试验结果表明,采用反渗透膜过滤方式提高蛋白含量,杀菌温度118℃,发酵温度43℃;稳定体系琼脂添加量0.05%,果胶添加量0.19%,此条件下产品的感官、持水性和稳定性最佳。     

静电纺丝在增强锂离子电池隔膜中的应用

静电纺纤维膜是用作锂离子电池隔膜的理想材料,为满足实际生产要求,需对其进行增强处理。综述了现有的增强型静电纺纤维膜的制备方法,包括单一静电纺丝法、静电纺丝-后处理法以及静电纺丝与增强基材复合法等,介绍了增强型静电纺纤维膜的相关性能,并提出了未来增强型静电纺锂离子电池隔膜的发展趋势。     

乳状液膜法处理制浆黑液的研究现状

介绍了液膜分离技术应用于制浆黑液处理的方法和研究现状。     

鸡蛋壳膜资源的开发与应用前景

蛋壳与蛋壳内膜中具有很多有效成分,它们是饲料、食品、医药、化学、轻工等行业的宝贵原料。我国养禽数量多、蛋壳产量巨大,蛋壳膜的综合利用将大幅度提高蛋品工业的经济效益,减少环境污染。综述了近年来国内外此方面的研究现状,为鸡蛋壳膜资源的开发与应用提供了参考。     

液膜分离技术及其在生物、食品工业下游处理中的应用

液膜分离技术(liquid membrane technique)是近年来发展起来的分离、纯化和浓缩一步完成的新型分离技术,具有专一、高效、快速,经济简便等特点。文章中介绍了液膜的组成和类型、分离纯化浓缩的机理和其不稳定性等特性,叙述了其在脂肪酸、手性化合物、蛋白质、酒及果蔬汁等下游处理中的应用。此外,展望了其在生物、食品工业中的应用前景和发展方向。     

靛蓝染料废水的处理研究

采用膜技术和絮凝方法处理牛仔布印染过程中的生产废水。对经处理后的水色度和COD的去除进行了比较。膜法处理后的水要优于絮凝处理后的水,可回用于生产。