新型硅铝微粒的助留助滤性能研究

研究了实验室制备的硅铝微粒与阳离子淀粉(CS)、阳离子聚丙烯酰胺(CPAM)组成的微粒体系、湿部剪切力及其pH值对纸料助留助滤性能的影响.研究结果表明,硅铝微粒是一种性能优异的微粒助留助滤剂,与CS-CPAM构成的微粒体系有更好的助留和助滤性能,有更强的抗剪切能力和更宽的pH值适应范围.     

新型硅铝微粒的助留助滤性能

研究了自制硅铝微粒与阳离子淀粉(CS)、CPAM组成的微粒系统、湿部剪切力及其pH值对纸料助留助滤性能的影响。研究结果表明硅铝微粒是一种性能优异的微粒助留助滤剂，与阳离子淀粉-CPAM构成的微粒系统有更好的助留和助滤性能，有更强的抗剪切能力和更宽的pH值适应范围。     

阳离子聚合物/聚铝类微粒子助留助滤体系

微粒子助留助滤体系一般由带正电荷的合成或天然有机高分子聚合物和带负电荷的无机微粒子组成。与普通双聚合物助留体系相比,微粒子助留助滤体系不仅提高纸料留着率 (尤其对纸料中的细小组分有较高的留着率 ),还改善纸料滤水性能和纸页匀度。国外采用的微粒子助留助滤体系多为阳离子聚丙烯酰胺 /膨润土和阳离子淀粉 /胶体二氧化硅。我国的微粒子助留助滤技术还处于研究与开发阶段,其中在阳离子淀粉 /(现场合成 )胶体氢氧化铝微粒子体系基础上发展起来的阳离子聚合物 /聚铝类微粒子体系就不需要专门的商品微粒子,而是利用聚铝类无机聚合…     

硅铝微粒助留助滤系统在漂白麦草浆中的应用

研究了实验室自制硅铝微粒在造纸湿部与阳离子淀粉(CS)、CPAM组成的微粒系统各组分用量及剪切力对纸料助留助滤性能的影响.研究结果表明硅铝微粒是一种性能优异的微粒助留助滤剂,与阳离子淀粉-CPAM构成微粒系统时有更好的助留和助滤性能,各组分的适宜添加量为阳离子淀粉1%、CPAM 0.02%、硅铝微粒0.1%～0.3%(均为质量分数);CPAM在高剪切下加入能获得更好的助留效果.     

氢氧化镁铝及其微粒助留系统

介绍了近年来微粒助留体系的研究进展,尤其是无机阳离子微粒助留体系,着重论述了阳离子氢氧化镁铝与阴离子聚合物的协同助留作用及其发展。     

胶体氢氧化铝助留助滤性能探讨

本文探讨了硫酸铝溶液一氢氧化钠溶液滴定曲线及其随PH值变化后铝盐化学形态、电位变化过程，以及胶体氢氧化铝的助留助滤性能。研究结果表明胶体氢氧化铝的PH值、纸料系统的PH值对CS-胶体氢氧化铝构成的助留系统的助留助滤效果起着重要作用，阳离子淀粉和胶体氢氧化铝用量都在1.0％附近构成的助留系统具有最佳的助留助滤性能。     

铝铵基阳离子淀粉对提高脱墨浆助留助滤性能的作用

研究了水溶剂法制备的铝铵基阳离子淀粉,并考察对脱墨浆的助留、增强作用。结果表明:铝铵基阳离子淀粉(ACS)对废纸脱墨浆具有很好的助留效果,加入量在1.0%时助留效果最好,此时,网下白水浊度为5.2NTU,成纸灰分含量为23.27%;ACS在用量较少(0.5%左右)时能同时提高纸张的强度和细小纤维的留着率,具有助留和增强的双重作用。     

新型助留剂在新闻纸助留助滤系统中的应用研究

对一种新型改性聚丙烯酰胺助留剂N在新闻纸助留助滤系统中的应用进行了初步研究；结果表明，助留剂N具有较好的提高浆料滤水性能和细小组分留着率的能力，对改善湿部环境、保持纸张强度、降低生产成本有较明显的效果。     

AM-DMDAAC共聚物的助留助滤性能研究

将自制的不同阳离子度和分子量的AM—DMDAAC二元共聚物加入到漂白木浆和漂白苇浆中，测定了助留助滤效果。结果表明：5种试样均有一定的助留助滤效果，阳离子度、分子量大小、加入量对助留助滤效果产生显影响。     

助留助滤作用机理及助留助滤体系的发展

该文对助留助滤剂的作用机理以及助留助滤体系的发展历程进行了分析总结,并结合现阶段造纸行业的发展现状,对未来的研究方向进行了展望。     

贵州黔南地区泡制酸菜中酵母菌的分离与鉴定

采用纯培养的方法从贵州黔南地区20份自然发酵泡制酸菜中分离出115株酵母菌,通过WL培养基观察菌落特征,并结合显微细胞形态及生理生化特性,将115株酵母分为17种类型。从每种类型中挑选一株进行26S rDNA D1/D2区系列测定,通过序列分析及构建系统发育树,进行种属鉴定。结果表明：17类酵母共115株分属于11个属,其中30.43%为Kazachstania酵母、26.96%为毕赤酵母属(Pichia)、17.39%为地霉属(Geotrichum)、4.35%为假丝酵母属(Candida)、3.48%为耶罗威亚酵母属(Yarrowia)、3.48%为丝孢酵母属(Trichosporon)、3.48%为Meyerozyma酵母、2.61%为有孢汉逊酵母属(Hanseniaspora)、2.61%为Wickerhamomyces酵母、2.61%为Apiotrichum酵母、2.61%为棒孢酵母属(Clavispora)。     

Outcome of clinical mastitis in dairy heifers assessed by reexamination of cases one month after treatment

Heifers that were treated for clinical mastitis prior to parturition or within 14 d postpartum were reexamined approximately 1 mo after treatment. Clinical examination of the heifers and microbiological examination of quarter milk samples were carried out on both occasions. Of the 1000 heifers included in the study, 10.9% were culled within 28 d after treatment. Udder damage caused by mastitis was the only or main reason for culling in 96% of those heifers. In comparison, 4.5% of nonmastitic heifers from the same herds were culled within 30 d postpartum. Twenty-five percent of those heifers that were not culled at d 28 after treatment had at least one nonfunctional quarter at that time. One thousand one hundred twenty-two quarters that were clinically affected at the time of treatment were reexamined; 22% were nonfunctional, 14% were still affected by clinical mastitis, 12% had subclinical mastitis, 5% had a latent infection with coagulase-positive staphylococci or Streptococcus dysgalactiae, and 46% were bacteriologically negative and had a normal cell count at the time of reexamination. High percentages of nonfunctional quarters were observed among those quarters that were infected with Arcanobacterium pyogenes or with coagulase-positive staphylococci at treatment. When all quarters that were clinically affected at treatment were considered, 40% of quarters were cured and were still in lactation at reexamination. Quarters infected with coagulase-negative staphylococci had a higher cure rate than quarters infected with other organisms. At reexamination, clinical signs of thelitis were observed in many of those quarters that were nonfunctional following the episode of clinical mastitis and also in 25% of lactating quarters in which clinical mastitis persisted.     

Effects of Vacuum Packaging and Potassium Sorbate on Yield, Yeast and Mold Growth, and Quality of Dry-Cured Hams

Two trials were conducted. In the first trial hams were cured by a standard process and aged 1 month at 24°C. Group I hams were not packaged or treated. Group II hams were vacuum packaged and Group III hams were dipped in a 2.5% potassium sorbate solution and also vacuum packaged. All hams were examined after 1 month and the treated group was dipped in a 5% sorbate solution, vacuum packaged and aged an additional 2 months. Vacuum packaging practically eliminated further weight loss while potassium sorbate reduced but did not eliminate mold growth. In the second trial hams were again cured by a standard process and aged at 24°C until they were officially country hams (18% weight loss). Group I hams were not treated whereas group II hams were dipped in a 10% potassium sorbate solution. All were vacuum packaged. After aging one month they were unpacked, weighed, and examined for molds. No significant weight loss had occurred but mold counts were lower in the dipped group. The dipping procedure was reversed so that group I hams were treated and group II hams were not treated. All hams were again vacuum packaged and held a second month. No additional weight loss was noted. Mold growth, though not eliminated, was minimal, and visual and aroma scores for the cut hams were similar and highly acceptable. Tenderness, flavor, saltiness, and overall satisfaction scores for cooked slices were similar and highly acceptable. In general, mold growth can be greatly reduced by the use of potassium sorbate and weight loss can be controlled by vacuum packaging.     

大豆蛋白水解物中肽分子分布的研究

研究采用超滤法与凝胶过滤色谱（GFC）相结合实验方法就大豆蛋白酶解产物寡肽混合物的分子量的分布状况进行了测定，研究结果表明，木瓜蛋白酶与Asl.398蛋白酶的酶解物中以分子量在1000D以下的小肽为主：木瓜蛋白酶解产物中分子量1000D以下的占63.9%,1000-2000D之间的4.64%,2000-4000D之间的占8.21%,4000-10000D之间的占8.20%，分子量10000D以上的占15%；Asl.398蛋白酶酶解物中分子量1000D以下的占72.1%,1000D-2000D的占6.42%,2000D-4000D之间的占2.5%,4000-10000D之间的占3.92%,10000D以上的占15%。     

Isolation and identification of nontuberculous mycobacteria from foods as possible exposure sources

A variety of foods collected from local supermarkets and produce stands were examined as possible sources of nontuberculous mycobacterial exposure. Food samples were combined with sterile ultrapure water and manually shaken. To remove large particles, the suspensions were filtered through a sterile strainer, centrifuged, and the supernatants were discarded. The food pellets were stored at -75 degrees C. The pellets were treated with either oxalic acid or sodium hydroxide-sodium citrate solutions to reduce contamination by nonmycobacterial organisms. Decontaminated pellets were cultured on both Middlebrook 7H10C agar and Middlebrook 7H10C agar with supplemental malachite green. Plates were observed for growth at 2 and 8 weeks. Isolates demonstrating acid-fastness were identified to species using polymerase chain reaction and restriction enzyme analysis. Nontuberculous mycobacteria (NTM) were recovered from 25 of 121 foods. Six different species of NTM were isolated, the most predominant being Mycobacterium avium.     

Temperatures and ages of boxed beef packed and distributed in Canada

Boxes of beef were examined when product was packed and when boxes were loaded out of five packing plants, when boxes were loaded into and loaded out of seven refrigerated warehouses, and when boxes were received and opened at 21 retail stores. At each stage of handling at each facility, the boxes to be examined were selected at random. For each selected box, the temperature of product at the centre of the box was measured, and the date of packing and the plant of origin were noted. When cuts were packed, the minimum, median and maximum temperatures were about 2, 6 and 18 °C, respectively. Temperatures were successively lower when boxes were loaded out of packing plants, into warehouses and out of warehouses. When loaded out of warehouses, the minimum, median and maximum temperatures were about −2, 1 and 8 °C, respectively. The ranges of temperatures were similar, but the median temperatures were about 2 or 1.5 °C, respectively, when boxes were received at or were opened at retail stores. At packing plants and warehouses, the temperatures of manufacturing and ground beef were lower than those of cuts, but at the retail store the temperatures of all types of product were similar. When boxes were opened at retail stores, the minimum, median and maximum ages of cuts were about 2, 20 and 130 days, respectively; and the corresponding ages for manufacturing and ground beef were 2, 7 and 56 days, respectively. The data indicate that boxed beef is generally cooled to and maintained at temperatures within the range sought by the meat industry. However, cooling to chiller temperatures of product that is packed while warm can take several days; and some product is held for times that are excessive in view of the temperatures of boxed beef.     

多环境大豆种子维生素E含量遗传分析

利用高效液相色谱测定了三个地点的大豆品种合丰25与Bayfield及其衍生的144个重组自交系种子中的维生素E含量,运用主基因＋多基因混合遗传模型,对三个地点的大豆种子的维生素E进行了遗传分析。结果表明：在哈尔滨地区α-生育酚为2对主基因＋多基因遗传模型;γ-生育酚为1对主基因＋多基因遗传模型;δ-生育酚为2对主基因＋多基因遗传模型;在呼兰地区α-生育酚为3对主基因＋多基因遗传模型;γ-生育酚为2对主基因＋多基因遗传模型;δ-生育酚为2对主基因＋多基因遗传模型;在绥化地区α-生育酚为无主基因＋多基因遗传模型;γ-生育酚为3对主基因＋多基因遗传模型;δ-生育酚为2对主基因＋多基因遗传模型。     

江西省食源性沙门菌血清分型及脉冲场凝胶电泳指纹图谱研究

研究江西省食源性沙门菌的血清型,用脉冲场凝胶电泳(PFGE)方法对优势血清型进行分子分型,建立江西省食源性沙门菌PFGE指纹图谱资料库,为食源性疾病溯源提供数据。方法 对136株食源性沙门菌进行血清分型,对其中优势血清型德尔卑沙门菌菌株进行PFGE分型,获得分子分型指纹图谱,运用Bionumerics v6.6软件进行聚类分析。结果 136株沙门菌分离株血清群以B群为主,优势血清型主要是德尔卑沙门菌(49.26%),67株德尔卑沙门菌可分为41个型别的PFGE指纹图谱(相似值100%的为同一PFGE型别),主要集中在3个型别中。结论 江西省食源性沙门菌血清型分布呈多样性,优势血清型是德尔卑沙门菌,生肉制品是其主要的来源,同种血清型别的PFGE指纹图谱无相关性。     

乳酸菌ATCC367菌株在不同培养条件下的生长特性差异

目的通过分析乳酸菌ATCC367在不同pH环境下的生长曲线和pH值曲线的差异,探讨乳酸菌的生长规律。方法配制不同成分、不同pH值的培养基,分别进行菌株培养并测定A600和pH值,获得生长曲线和pH变化曲线。结果乳酸菌ATCC367菌株在pH 3.5和添加壳寡糖的培养基上生长受到抑制,适宜生长的pH值环境为3.5～6.5,添加葡萄糖能促进其指数生长,添加30 g/L的氨基酸可能不利于生长。结论ATCC367菌株可能根据生长环境和能量来源的不同,动态调节不同代谢途径,以获得最佳生长状态。