系列基于苯二酚的A（LS）2型胆固醇衍生物的合成及凝胶性研究

以邻/间/对苯二酚、胆固醇、丁二酸酐等为原料,经过两步不同的酯化反应,合成了三种A(LS)2型胆固醇衍生物,考察三种化合物在不同有机溶剂中的凝胶性能,发现基于邻苯二酚的化合物P1能够在乙酸乙酯中形成稳定的凝胶,是一种有效的小分子有机凝胶因子。     

新型乳化体系及其在化妆品中的应用（Ⅱ）——双凝胶体系

双凝胶体系是一种在不添加（或少量添加）表面活性剂的情况下，将一种液体以凝胶的形式（如油凝胶或水凝胶）分散在另一种与其不相容的凝胶（如水凝胶或油凝胶）中的特殊乳化体系。该体系兼具水凝胶和油凝胶的双重优势，不仅能同时递送亲水性和亲油性物质，而且展现出比单一凝胶更优异的性能。加之体系中不含（或含少量）表面活性剂，不会引起对敏感肌肤的刺激和脱水问题，使其在化妆品领域具有广阔的应用前景。本文首先介绍了凝胶及双凝胶体系；总结了影响双凝胶体系性质的因素，包括凝胶剂、油/水凝胶比例、油脂性质以及制备工艺等；归纳了双凝胶产品的皮肤安全性、稳定性、锁水保湿性、缓释性及肤感等。在此基础上，阐述了双凝胶体系在化妆品领域应用的研究进展。最后指出了目前双凝胶体系在化妆品领域应用中所面临的问题，并对后续亟待解决的问题提出了个人看法，旨在为性能优异的双凝胶产品的开发及应用提供基础信息，为双凝胶体系的发展方向提供参考。     

超电容器用炭气凝胶预凝动态过程的电导法研究

以间苯二酚和甲醛为反应物，氢氧化钙和碳酸钠为催化剂，通过溶胶一凝胶法制备出有机凝胶。研究了不同催化剂及其含量下凝胶化过程中电导率的变化。结果表明，电导法是一种有效的监测凝胶化动态过程的方法，具有方便、实时、精确、快捷的优点，对深入认识和研究反应体系有重要意义。     

小分子有机胶凝剂和凝胶推进剂的研究进展

系统地介绍了胆固醇类衍生物、金属有机化合物、金属脂肪酸盐类等小分子有机胶凝剂(LMOG)的性质，简要阐述了影响有机胶凝剂胶凝能力的诸多因素。概括了有机凝胶在推进剂、海上凝油、微机械设计、物质分离等方面的应用。在此基础上，提出了未来小分子有机凝剂研究中应该注意的有关问题。     

炭气凝胶研究进展

介绍了一种新型轻质纳米级多孔性非晶炭素材料－－炭气凝胶的制备方法、性能以用途，提出了存在的问题和发展的前景。     

基于液态金属的水凝胶应变传感器

近年来，基于导电水凝胶的应变传感器发展迅速，液态金属作为一种新型导电材料由于具有高导电性、良好的生物相容性、柔性和可变性，在导电水凝胶传感器的制备和应用中受到了越来越多的关注。本文介绍了液态金属以分散的液滴和连续的流体两种形式在导电水凝胶制备中的应用，及所制备的基于液态金属导电水凝胶传感器的性能，最后，对基于液态金属的水凝胶传感器的应用前景进行了展望。     

自愈合水凝胶的研究进展

自愈合水凝胶作为一种新型功能凝胶材料，目前在现代科学研究中展现了十分突出的应用前景。本文对水凝胶的自愈合机理进行了描述和分类。非共价交联水凝胶与共价交联水凝胶都有着不同的自愈合性质。非共价交联水凝胶主要以氢键、疏水相互作用以及离子键来实现其自愈合的性质，而共价交联水凝胶的自愈性主要依靠动态共价键以及金属配位键。本文还描述了近些年来自愈合水凝胶在生物医疗、3D打印、可穿戴电子产品以及离子吸附的部分应用。最后，对自愈合水凝胶未来的发展作了展望。     

快速溶胶—凝胶法制备SiO2气凝胶的研究

以正硅酸乙酯（TEOS）为原料，以乙醇为溶剂，以盐酸和氨水为催化剂，用溶胶-凝胶法制得了SiO2气凝胶，大大加快了溶胶-凝胶的反应速率，使得凝胶时间减少至几分钟甚至于更短，TEM测试结果表明所制备的SiO2气凝胶具有纳米多孔结构（骨架颗粒为80nm)实验对溶胶-凝胶过程在不同条件下进行了研究。并对其凝胶过程作了初步探讨。得出了最佳工艺条件。     

环氧化合物法制备金属氧化物气凝胶研究进展

环氧化合物法作为一种新的溶胶-凝胶制备金属氧化物气凝胶的方法近年来得到了长足发展。综述了环氧化合物法制备不同价态金属氧化物气凝胶的研究进展，并阐述了其在溶胶-凝胶过程中的作用机理     

炭凝胶的研究进展

炭凝胶是一种质轻、大比表面积、纳米级的中孔炭材料，它中孔发达、导电性良好，电化学性能稳定，是制备高比能量，高比功率电化学电容器的理想电极材料。本文概述了炭凝胶的制备方法，机理、结构性能及其应用，并说明了以降低成本和简化工艺为目的，对炭凝胶在原料和干燥方法上的改进。     

依泽替米贝中间体的新工艺

(4S)-3-[(5S)-5-(4-氟苯基)-5-羟基戊酰基]-4-苯基-1,3-氧氮杂环戊烷-2-酮(1)是依泽替米贝的重要中间体,依泽替米贝是第一个选择性胆固醇吸收抑制剂,它可同时干扰食物来源的胆固醇及肠肝循环中由肝脏合成的胆固醇的吸收,而对其它营养成分的吸收并不产生影响。本文利用原位生成的R-OMe-CBS催化剂不对称还原得到1,反应条件温和、成本降低,同时实更加适应实际的工业生产。     

胆甾醇在超临界CO_2中的溶解度测定与关联

利用动态法测定了胆甾醇在超临界CO2中的溶解度。在10—30 MPa,313—343 K下,胆甾醇的溶解度摩尔分率为10-6—10-4。引入与密度有关的混合规则,将二元交互参数表示为密度的函数,采用PR状态方程,关联胆甾醇在超临界CO2中的溶解度。改进后的溶解度模型克服了采用经典混合规则的PR方程不能很好地关联胆甾醇大分子物质的缺陷,大大提高了关联精度。     

Fish oil prevents change in arachidonic acid and cholesterol content in rat caused by dietary cholesterol

Rats were fed diets high in either saturated fat (beef tallow) or α-linolenic acid (linseed oil) or eicosapentaenoic and docosahexaenoic acids (fish oil) with or without 2% cholesterol supplementation. Consumption of linseed oil and fish oil diets for 28 days lowered arachidonic acid content of plasma, liver and heart phospholipids. Addition of 2% cholesterol to diets containing beef tallow or linseed oil lowered 20∶4ω6 levels but failed to reduce 20∶4ω6 levels when fed in combination with fish oil. Feeding ω3 fatty acids lowered plasma cholesterol levels. Addition of 2% cholesterol to the beef tallow or linseed oil diet increased plasma cholesterol concentrations but not when fish oil was fed. Feeding the fish oil diet reduced the cholesterol content of liver, whereas feeding the linseed oil diet did not. Dietary cholesterol supplementation elevated the cholesterol concentration in liver in the order: linseed oil > beef tallow > fish oil (8.6-, 5.5-, 2.6-fold, respectively). Feeding fish oil and cholesterol apparently reduced 20∶4ω6 levels in plasma and tissue lipids. Fish oil accentuates the 20∶4ω6 lowering effect of dietary cholesterol and appears to prevent accumulation of cholesterol in plasma and tissue lipids under a high dietary load of cholesterol.     

Integral kinetic model for studying quercetin degradation and oxidation as affected by cholesterol during heating

The degradation and oxidation of quercetin, as affected by cholesterol during heating at 150 °C, was kinetically studied using non-linear regression models. Both TLC and HPLC were used to monitor the changes of quercetin, cholesterol and cholesterol oxidation products (COPs) during heating. The formation of COPs, including triol, 7-keto, 7α-OH and 7β-OH, was completely inhibited during the initial 30 minute heating period in the presence of 0.02% quercetin, accompanied by reduction in cholesterol peroxidation and degradation. However, the quercetin degradation or oxidation proceeded fast, with the rate constants (h(-1)) in the presence of nitrogen, oxygen and the combination of oxygen and cholesterol being 0.253, 0.868 and 7.17, respectively. When cholesterol and quercetin were heated together, the rate constants (h(-1)) of cholesterol peroxidation, epoxidation and degradation were 1.8 × 10(-4), 0.016 and 0.19, respectively. The correlation coefficients (r(2)) for all the oxidative and degradation reactions ranged from 0.82-0.99. The kinetic models developed in this study may be used to predict the degradation and oxidation of quercetin as affected by cholesterol during heating.     

Failure to demonstrate degradation of [4-14C] cholesterol to volatile hydrocarbons in rats and in human fecal homogenates

The inability of previous workers to recover completely the radioactivity from ingested [4-14C] cholesterol has led to the hypothesis that the colonic flora of some individuals degrade the sterol nucleus to volatile hydrocarbons, particularly CH4. In the present investigation, the production of radioactive volatiles was measured following incubation of [4-14C] cholesterol with 8 human fecal homogenates or after instillation of the labeled sterol into the cecum of 3 rats housed in a closed rebreathing system. Three of the 8 homogenates and each of the 3 rats produced copious CH4. However, analysis by combustion demonstrated no radioactivity above background in the volatile headspace of the homogenates or the gas space of the closed system housing the rats, indicating that less than 0.001% of the number 4 carbon of [4-14C] cholesterol could have been converted to volatile hydrocarbons. This study, therefore, provides no support for the concept that volatile products account for the incomplete recovery of ingested sterols observed in certain subjects. However, this hypothesis can not be excluded entirely until similar results are obtained with subjects who can be shown to degrade cholesterol.     

Dietary oxidized cholesterol modulates cholesterol metabolism and linoleic acid desaturation in rats fed high-cholesterol diets

The interactive effect of high dietary levels of oxidized cholesterol on exogenous cholerterol and linoleic acid metabolism was examined in male 4-wk-old Sprague-Dawley rats given high-cholesterol diets. The rats were pair-fed purified diets free of or containing either 0.5% cholesterol alone or both 0.5% cholesterol and 0.5% oxidized cholesterol mixture (containing 93% oxidized cholesterol) for 3 wk. Hepatic 3-hydroxy-3-methylglutaryl CoA reductase activity was reduced in rats given cholesterol alone or both cholesterol and oxidized cholesterol. However, hepatic cholesterol 7α-hydroxylase activity was lowered only when rats were given both cholesterol and oxidized cholesterol, although dietary cholesterol increased this activity. Reflecting this effect, acidic steroid excretion was lowest among the groups of rats given cholesterol and oxidized cholesterol. On the other hand, the activity of hepatic Δ6 desaturase, a key enzyme in the metabolism of linoleic acid to arachidonic acid, was increased in rats given both cholesterol and oxidized cholesterol, although dietary cholesterol alone lowered its activity. As a result, the Δ6 desaturation index, 20∶3n-6+20∶4n-6/18∶2n-6, in liver and serum phosphlipids tended to be higher in the group fed both cholesterol and oxidized cholesterol than in the one fed cholesterol alone. Thus, dietary oxidized cholesterol significantly modulated exogenous cholesterol metabolism and promoted linoleic acid desaturation even when it was given at high levels together with a high cholesterol diet.     

DCC法合成胆甾醇酯

研究以二环己基碳二亚胺(DCC)作脱水剂,分别用4-二甲胺基吡啶(DMAP)和N,N-二甲基苯胺作除水促进剂,胆甾醇与丙酸、苯甲酸在室温下反应合成液晶材料胆甾醇丙酸酯和胆甾醇苯甲酸酯的方法.该方法反应条件比较温和,用DMAP作除水促进剂时,胆甾醇酯产率比较高.发现用N,N-二甲基苯胺作除水促进剂也可以合成胆甾醇丙酸酯,这有利于降低胆甾醇丙酸酯合成成本,但合成胆甾醇苯甲酸酯时没有成功.     

Alteration of cholesterol metabolism by 4-0-methylascochlorin in rats

The effect of 4-0-methylascochlorin (MAC), an experimental hypocholesterolemic agent, on cholesterol metabolism was investigated in rats in two separate experiments. The administration of MAC for 2 and 6 consecutive weeks at daily doses of 100–135 mg/kg resulted in reduction in serum cholesterol levels of 16% after 2 weeks of treatment in the first experiment, and 13% after 6 weeks in the second experiment in comparison to the corresponding controls. MAC administered at a daily dose of 100 mg/kg for 2 weeks showed a significant increase in the biliary excretion of bile acids and cholesterol in bile-duct cannulated rats with or without the administration of taurocholate. In the second experiment, MAC treatment for 6 weeks produced a marked increase in the fecal output of acidic sterols during a 2 to 6-week period. MAC treatment also further enhanced hepatic cholesterol 7α-hydroxylase in the rats. Therefore, it appears that the mechanism of serum cholesterol lowering due to MAC is related to the enhancement of hepatic bile acid synthesis and the increase in biliary and fecal excretion of bile acids.     

Effects of feeding chenodeoxycholic acid on metabolism of cholesterol and bile acids in germ-free rats

The aim of this investigation was to study the influence of chenodeoxycholic acid administration on cholesterol and bile acid synthesis in germ-free rats. Seven rats were fed a basal diet and 2 groups of 4 rats received the same diet supplemented with 0.4 and 1% chenodeoxycholic acid, respectively. After 6 weeks, feces were collected in one 3- and one 4-day pool for analysis of cholesterol and bile acids. When the sampling period was finished, the rats were killed and the liver microsomal fractions isolated. The activities of HMG CoA reductase and cholesterol 7α-hydroxylase were determined, the 7α-hydroxylase by a mass fragmentographic method. The 2 dominating bile acids in the untreated rats were cholic acid and β-muricholic acid. During treatment with chenodeoxycholic acid, 60–70% of this bile acid was converted into α- and β-muricholic acid, indicating a high activity of the 6β-hydroxylase. The excretion of cholic acid was almost completely inhibited and the 7α-hydroxylase activity was decreased ca 75% in the rats fed 1% chenodeoxycholic acid. The activity of the hepatic HMG CoA reductase was unchanged. The fecal excretion of cholesterol increased 2–3 times. An accumulation of cholesterol was seen in the rats treated with 1% chenodeoxycholic acid, which was probably a result of the decreased catabolism of cholesterol to bile acids.