Biochemical conversion of sweet sorghum bagasse to succinic acid

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单滴微萃取—气相色谱—质谱联用法检测食品中5种邻苯二甲酸酯类塑化剂

建立酱油、醋和果汁样品中5种邻苯二甲酸酯类(PAEs)塑化剂的单滴微萃取结合气相色谱—质谱联用检测方法。采用气相色谱—质谱仪进行测定。结果表明:5种邻苯二甲酸酯类塑化剂在1~10mg/mL范围内线性关系良好(r≥0.995);5种PAEs在3种样品基质中3个添加水平的平均回收率在75.4%~113.0%,日内精密度和日间精密度分别为2.4%~7.3%和1.9%~8.5%。5种PAEs中DBP检出率最大为100%,且检出量均超出GB 9685—2008规定的限值0.3 mg/kg。塑料袋、塑料瓶和纸盒包装样品中PAEs的量高于玻璃瓶包装的样品。该方法操作简单,快速,灵敏度高,可以满足酱油、醋和果汁等类样品中PAEs的检测要求。     

Properties of rigid polyurethane foams prepared from recycled aircraft deicing agent with hexamethylene diisocyanate

Polyurethane (PUR) rigid foams were prepared from recycled aircraft deicing agent (aircraft deicing fluid) with reaction of hexamethylene diisocyanate at temperature of 55°C. The effect of [NCO]/[OH] ratio on properties of microscopic structure, cell size distribution, compressive strength, apparent density, as well as thermal conductivity (k) was studied. Higher [NCO]/[OH] ratio helped achieve better micromorphology, higher apparent density, and compressive strength of the PUR foams. With the [NCO]/[OH] ratio of 0.75 and 0.8, some shrinking happened during foam rising, causing a decrease in total volume of the PUR foam, and leading to higher apparent density as well as sharply increased compressive strength. All PUR foams displayed good thermal insulation properties in this study. With [NCO]/[OH] ratio increased from 0.7 to 0.8, the k value increased significantly from 34.3 to 42.2 mW m^?1 K^?1. The k value here was chiefly governed by the apparent density of the foams, which was in turn a function of the ratio of [NCO]/[OH]. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2013     

牛磺酸对大鼠的减重降脂作用

目的:探讨牛磺酸饮水对高脂血症大鼠减重降脂的作用。方法:根据血清总胆固醇(TC)和体重将SD大鼠随机分为对照组、高脂模型组和牛磺酸(低、高)剂量组。对照组摄食普通饲料,其余三组摄食高脂饲料,牛磺酸组饮用牛磺酸水溶液。饲养12周后处死动物,检测血清TC、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、甘油三酯(TG)水平,血清谷胱甘肽过氧化物酶(GSH-PX)和超氧化物歧化酶(SOD)活力;粪便中总胆汁酸(TBA)含量;肝脏TC、TG、游离脂肪酸(FFA)、还原型谷胱甘肽(GSH)、肝糖原的含量和GSH-PX酶活力。结果:高剂量牛磺酸显著降低高脂饮食大鼠的体重,两个剂量牛磺酸都可以显著降低大鼠附睾脂肪垫指数;高剂量牛磺酸显著降低大鼠血清TC、LDL-C、肝脏FFA和肝糖原水平,两个剂量牛磺酸对肝脏TC和TG均无显著影响,但都可显著增加粪便TBA含量;两个剂量牛磺酸都可以显著升高大鼠血清GSH-PX和肝脏GSH-PX、还原型GSH。结论:牛磺酸主要通过促进胆固醇转化为胆汁酸,并随粪便排出、加强脂质代谢减少肝脏FFA堆积、提高机体抗氧化能力等途径发挥减重降脂功效,但其减重降脂机制还需深入研究。