水性聚氨酯改性研究新进展及其应用

本文介绍了水性聚氨酯的性能特点,并且重点阐述了水性聚氨酯改性方法:交联改性、环氧树脂改性、有机硅改性、丙烯酸改性、有机硅丙烯酸双改性、纳米无机材料改性.     

水性聚氨酯改性研究新进展及其应用

本文介绍了水性聚氨酯的性能特点,并且重点阐述了水性聚氨酯改性方法：交联改性、环氧树脂改性、有机硅改性、丙烯酸改性、有机硅丙烯酸双改性、纳米无机材料改性。     

纺织染整用有机硅类产品改性的研究进展

介绍了纺织染整中常见的有机硅类助剂改性技术,包括有机硅的环氧基改性、羧基或羟基改性、氟烃基改性、氨烃基改性、聚醚改性等。指出了目前有机硅改性的研究重点,并对纺织染整行业中有机硅类产品改性的发展方向进行了展望。     

胶原蛋白的化学改性方法研究新进展

综述了胶原蛋白改性的两类化学改性方法：交联改性和接枝改性。阐述了每一种改性方法的机理和优缺点,并且总结了两种改性方法的最新研究成果。     

超滤膜改性技术研究进展

综迷了超滤膜改性国内外现状及研究进展,介绍了物理共混改性、化学改性、低温等离子体改性、高能射线辐照改性和紫外辐照改性等方法及其改性效果与特点,并指出这些方法的应用前景。     

耐热聚乳酸材料的研究进展

针对工业化生产聚乳酸产品普遍存在力学强度低、韧性差、结晶速度缓慢、结晶度低、耐热性能差等问题,综述了国内外关于提高聚乳酸材料耐热性能的方法及其改性机制,将其总结分为共混改性、链结构改性和结晶改性,其中:共混改性包括聚合物复合改性和填充改性,链结构改性包括共聚改性和交联改性,结晶改性包括添加成核剂改性和加工工艺改性。简要分析了各改性方法的优缺点,重点介绍并讨论了聚乳酸立构复合晶的形成及其影响因素,并对聚乳酸材料的发展方向和前景进行了分析与展望。指出国内外最受青睐的改性方法是通过结晶改性配合加工工艺条件改性进行调控,更高效地改善聚乳酸材料的耐热性能。     

水性聚氨酯改性技术研究进展

详细叙述了水性聚氨酯的各种改性技术,如交联改性,聚丙烯酸酯,环氧树脂改性,有机硅改性,纳米技术改性,天然产物改性等,并对水性聚氨酯的发展前景进行了展望.     

改性蒙脱土对铬离子吸附性能的研究进展

介绍了不同方法改性蒙脱土,包括酸活化改性、物理包覆改性、柱撑交联改性、有机季铵盐改性、聚合物改性、天然高分子改性等,综述了改性蒙脱土对水体中铬离子的吸附能力和吸附机理,并对其在含铬废水处理中的发展提出了几点建议。     

改性对大豆蛋白可生物降解材料性能的影响

介绍了大豆蛋白可生物降解材料的研究意义;综述了大豆蛋白可生物降解材料的改性方法,包括增塑改性、交联剂改性、酸调改性、还原剂改性、填充改性、微波处理、超声波处理、紫外辐射处理等.     

魔芋葡苷聚糖的改性及其研究进展

综述了魔芋葡苷聚糖的改性方法,包括共混改性、化学改性及生物改性方法,并介绍了改性后的魔芋葡苷聚糖的应用研究进展。     

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)。     

北京市市售带壳牡蛎致病性弧菌污染状况调查

目的了解北京市市售带壳牡蛎致病性弧菌污染状况。方法 2014年2~11月每月在某水产品批发市场的摊位抽样200只带壳牡蛎,共80份样品(其中腮和肠样品分别为40份)。用常规培养方法检测牡蛎腮和肠(含便)中致病性弧菌,对副溶血性弧菌进行血清学分型,荧光定量PCR检测副溶血性弧菌毒力基因tdh、trh和tlh。结果 80份牡蛎样品中,致病性弧菌阳性样品检出率为62.50%(50/80),副溶血性弧菌阳性菌株检出率为33.75%(27/80),溶藻弧菌阳性菌株检出率为31.25%(25/80);各牡蛎腮和肠样品中,致病性弧菌阳性检出率为67.50%(27/40)和57.50%(23/40);27株副溶血性弧菌共9种血清型;毒力基因检测结果表示,tlh均为阳性,tdh和trh均为阴性。结论北京市市售带壳牡蛎中致病性弧菌污染严重,以副溶血性弧菌和溶藻弧菌检出为主。     

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.     

基于UPLC-MS/MS的3 个李品种果实初生代谢物分析

以蜂糖李、空心李和脆红李果实为试材，采用超高效液相色谱-串联质谱技术对其初生代谢物进行定性和定量分析；并通过主成分分析、正交偏最小二乘判别分析和样本相关性分析等方法，比较各品种之间的差异代谢物，及通过京都基因与基因组百科全书富集分析，解析代谢通路之间的差异。结果表明：3 个李品种果实共检测到12 类307 种代谢物，主要包括氨基酸及其衍生物、核苷酸及其衍生物、有机酸、糖类、醇类、游离脂肪酸等代谢物。蜂糖李与脆红李之间的差异代谢物有70 种，其中43 种物质相对含量上调，27 种下调，分别占61.43%和38.57%；差异显著的代谢途径有5 条，分别是代谢通路、氨基酰-tRNA生物合成通路、缬氨酸、亮氨酸和异亮氨酸的生物合成通路、硫代葡萄糖苷的生物合成通路和赖氨酸降解通路。蜂糖李与空心李之间的差异代谢物有96 种，其中84 种物质上调和12 种物质下调，分别占87.50%和12.50%；差异显著的代谢途径有1 条为色氨酸代谢通路。空心李与脆红李之间共检测到75 种差异代谢物，其中19 种上调，56 种下调，分别占比为25.33%和74.67%；差异显著代谢途径有2 条分别是嘌呤代谢通路和硫代葡萄糖苷生物合成通路。     

食用猪油保质的研究进展

综述了人工合成抗氧化剂、天然抗氧化剂、复合型抗氧化剂、微生物抗氧化和物理方法在猪油保质研究中应用的原理和现状。发现人工抗氧化剂效果好,但有一定副作用;大部分天然抗氧化剂效果和稳定性不如人工抗氧化剂,且不易分离;物理方法保存无污染但操作繁琐;使用复合抗氧化剂、微生物抗氧化剂效果好,无副作用,使用方便,是猪油保质研究的发展趋势。     

新疆乳品中乳酸菌的多样性及耐药性分析

从新疆北部地区采集的样品中分离出103株乳酸菌并进行生理生化表型鉴定,对这些乳酸菌进行16S rRNA基因序列测序,构建系统发育树发现分离的乳酸菌主要为5个属分别为乳杆菌属、肠球菌属、乳球菌属、魏斯式菌属、明串珠菌属。采用纸片扩散法（K-B）研究不同属中不同乳酸菌对8种常见抗生素的耐药性分析。耐药性研究表明,分别有6株对链霉素、新霉素有耐药性,5株对红霉素有耐药性,7株对卡那霉素有耐药性,8株全部对萘啶酸具有耐药性,4株对万古霉素、四环素具有耐药性,2株对头孢唑肟存在耐药性。     

水牛乳中可培养乳酸菌多样性分析

采用传统分离培养方法,从三品杂交生水牛奶混合样品中,分离出105株乳酸菌,通过形态、生理生化、API细菌鉴定系统及16S rDNA基因序列分析方法对各菌株属种进行鉴定。16S rRNA序列分析结果显示,105株菌共分为5个属8个种,呈现较为丰富的乳酸菌多样性,具体数量分布为乳酸乳球菌21株,植物乳杆菌19株,格氏乳球菌17株,乳明串珠菌13株,食窦魏斯氏菌11株,肠膜明串珠菌8株,类肠膜魏斯氏菌6株,嗜热链球菌5株,糊精乳杆菌5株。由此可知,水牛乳中可培养乳酸菌优势菌群的主次关系为：乳酸乳球菌（Lactococcus lactis）＞植物乳杆菌（Lactobacillus plantaru）＞格氏乳球菌（Lactococcus garvieae）＞乳明串珠菌（Leuconostoc lactis）＞食窦魏斯氏菌（Weissella cibaria）,此为后续开发水牛乳中优势乳酸菌资源提供了良好的理论基础。     

海蜇不同组织营养组成分析及评价

为了实现海蜇资源的高值化综合加工利用,对新鲜海蜇不同组织(伞体、胃柱、肩板、口腕、棒状附属器、生殖腺和环肌)的基本营养组成、氨基酸组成、脂质组成及脂肪酸组成进行分析与评价。结果表明,海蜇不同组织水分均在93%以上,其中胃柱水分含量最高(97.93%);灰分含量也较高,其中伞体、棒状附属器、胃柱和口腕的灰分含量均高于50%(干质量)。以除去灰分后的干质量计,棒状附属器和环肌的粗脂肪含量较高,分别为18.80%和18.76%,其他组织的粗脂肪含量均较低;所有组织的粗蛋白含量均较高,特别是伞体、肩板和口腕,粗蛋白含量达62.81%~80.94%;总糖含量均较低,为6.28%~13.36%。海蜇的生殖腺和环肌组织检出20种氨基酸,必需氨基酸含量高于其他组织,且不同组织的必需氨基酸均在25%以上。海蜇各组织的磷脂含量较多,胆固醇含量相对较少;伞体和棒状附属器的饱和脂肪酸含量多于不饱和脂肪酸,其他组织相反。以上结果说明,海蜇各组织均含有较为丰富的营养价值,且各个组织的营养价值具有一定的特点,可针对不同组织的营养特点进一步开发与利用。     

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.     

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.