顺丁橡胶生产过程"门尼升值"的原因研究

研究了顺丁橡胶生产过程中门尼升值的原因。结果表明，顺丁橡胶生产后处理的膨胀干燥过程存在门尼升值现象。不同内在质量的顺丁橡胶门尼升值不同，正常条件下门尼升值发生于门尼粘度的测试过程。     

浅谈大型苯酐顺酐装置反应器包国产化

介绍引进大型苯酐顺酐装置固定床反应器包的两种结构；简述该反应器包在设计、材料、制造方面的关键问题；分析反复引进技术的利弊；通过论证认为，该大型反应器包国产化是完全可行的，并指出尚需解决的技术问题。     

The composition of hydrogenated fats by high-resolution13C nuclear magnetic resonance spectroscopy

The high-resolution¹³C nuclear magnetic resonance spectra of twelve hydrogenated fats have been examined. Each spectrum contains 50–100 signals and reveals much about the nature of the acyl chains of both double-bond position and configuration. The signals for the ω1, ω2 and ω3 carbon atoms give information on thecis andtrans isomers of the Δ15, Δ14, Δ13 and Δ12 18:1 esters, respectively. Allylic signals distinguish betweencis andtrans esters, and the proportion of totalcis to totaltrans isomers can be obtained from these. Olefinic signals are the most informative, and most of these have been assigned. This leads to a semi-quantitative estimate of the various 18:1 isomers present. Assignments are based mainly on information already in the literature, but some were confirmed after urea fractionation of the acids from a hydrogenated oil in whichcis andtrans monoene acids were separately concentrated.     

脯氨酸肽键数据集的构建

由分辨率<0.25nm,同一性(identity)<30％的2401条肽链中计算提取了全部顺式与反式脯氨酸肽键的位置,数目分别为1221个与26401个,从而建立了一个较大规模的脯氨酸肽键数据集。统计分析了该数据集的基本特征:肽键N端残基的分布、N端残基的二面角统计、在二级结构中的分布情况、顺式肽键在脯氨酸肽键中所占比例。此数据集对于进一步研究顺反X-Pro肽键的结构、与氨基酸序列之间的关系,以及肽链折叠动力学具有重要作用。     

Trans10,cis15 18:2 Isolated from Beef Fat Does Not Have the Same Anti-Adipogenic Properties as Trans10,cis12–18:2 in 3T3-L1 Adipocytes

During ruminal biohydrogenation of α‐linolenic acid, a non‐conjugated non‐methylene interrupted dienoic acid is formed containing a t10 double bond, namely t10,c15–18:2. The present study was designed to examine whether t10,c15–18:2 would exert similar anti‐adipogenic effects compared to t10,c12–18:2 in 3T3‐L1 adipocytes. Differentiated 3T3‐L1 adipocytes were treated with 35 or 70 µM of LNA, t10,c12–18:2, t10,c15–18:2, or bovine serum albumin (BSA) vehicle control for 120 h. Cellular triacylglycerol and protein were quantified using commercial colorimetric kits. Cells were analyzed for fatty acid composition and gene expression using gas chromatography and quantitative PCR, respectively. Trans10,cis12–18:2 decreased (P < 0.05) the adipocyte triacylglycerol (TAG) content, which was mainly related to a reduction in saturated fatty acids (SFA; e.g., 16:0 and 15:0) and cis monounsaturated fatty acids (c‐MUFA; e.g., c9–16:1 and c9–18:1). Trans10,cis12 also decreased (P < 0.05) the expression of genes related to fatty acid synthesis (ACACA, FASN), delta‐9 desaturation (SCD1), fatty acid elongation (ELOVL5), and fatty acid uptake (LPL) and upregulated (P < 0.05) the expression of the rate‐liming enzyme involved in fatty acid β‐oxidation (CPT1). In contrast, LNA and t10,c15–18:2 did not affect the gene expression and cellular content of the TAG, SFA, c‐MUFA, or SCD1 indices in adipocytes. Our findings suggest that t10,c15–18:2, despite having structural similarity to t10,c12–18:2 (presence of a trans‐10 double bond), does not exert anti‐adipogenic effects in 3T3‐L1 adipocytes.     

反式脂肪酸与人体健康

油脂在加工过程中由于加氢、长时间高温等引起脂肪酸结构变化,顺式脂肪酸转变为反式脂肪酸.反式脂肪酸易导致肥胖、心血管疾病、糖尿病等疾病;长时间高温脱臭后油脂中反式脂肪酸含量将增加4%～6%,最高达8%～9%.建议从改进油脂生产的脱臭工艺与设备及日常生活中减少油炸食品、洋快餐食品摄入等入手,减少反式脂肪酸的摄入.