Steroid‐Based Amphiphiles for Membrane Protein Study: The Importance of Alkyl Spacers for Protein Stability

Membrane proteins allow effective communication between cells and organelles and their external environments. Maintaining membrane protein stability in a non‐native environment is the major bottleneck to their structural study. Detergents are widely used to extract membrane proteins from the membrane and to keep the extracted protein in a stable state for downstream characterisation. In this study, three sets of steroid‐based amphiphiles—glyco‐diosgenin analogues (GDNs) and steroid‐based pentasaccharides either lacking a linker (SPSs) or containing a linker (SPS‐Ls)—have been developed as new chemical tools for membrane protein research. These detergents were tested with three membrane proteins in order to characterise their ability to extract membrane proteins from the membrane and to stabilise membrane proteins long‐term. Some of the detergents, particularly the SPS‐Ls, displayed favourable behaviour with the tested membrane proteins. This result indicates the potential utility of these detergents as chemical tools for membrane protein structural study and a critical role of the simple alkyl spacer in determining detergent efficacy.     

离子色谱法测定化妆品中的海藻糖

建立了一种高效阴离子交换-脉冲安培检测(HPAE-PAD)测定化妆品中海藻糖的方法。采用不同的样品前处理方法,用METROSEP CARB 1分离柱(150 mm×4.0 mm)进行分离,以200.0 mmol·L-1的NaOH溶液为流动相进行洗脱,7 min内可完成对样品的分析。结果表明,海藻糖的检出限为0.02 mg·L-1,峰面积的相对标准偏差为0.17%,保留时间的相对标准偏差为0.28%;化妆品中常见的甘油和丙二醇不会对其测定产生干扰,平均回收率为95.2%～99.2%。     

含吡啶小分子胶凝剂研究进展

简述了含吡啶结构的小分子胶凝剂的研究进展,介绍了这类胶凝剂的结构特点、胶凝行为和凝胶性能。     

气相色谱-负化学源质谱法测定化妆品中的硝基麝香类化合物

建立了一种用于测定不同化妆品中5种硝基麝香含量的气相色谱-负化学源质谱联用（NCI-GC/MS）方法。通过丙酮/正己烷混合液超声提取化妆品中的硝基麝香,提取液经气相色谱-负化学源质谱联用仪检测,氘代二甲苯麝香内标法定量。方法对化妆品中5种硝基麝香的加标回收率在88.81%～104.92%之间,相对标准偏差（RSD）不大于5.75%,在10.0～500.0μg/L范围内呈现良好的线性关系,灵敏度高,各物质的最低检测限可达到2.0～10.0μg/kg。方法操作简单,选择性好,能有效消除复杂基体干扰,可作为常见化妆品中硝基麝香类化合物含量检测的确证方法。     

一种制备低黏度稳定油包水体系的新方法

通过制备多种低黏度油包水体系,考察了含有阳离子表面活性剂棕榈酰胺丙基三甲基氯化铵的油包水体系的黏度、稳定性、界面张力和乳化体系显微结构,并对比评价了配合使用不同规格粉体、不同表面活性剂以及不同用量棕榈酰胺丙基三甲基氯化铵的油包水体系的稳定性。结果表明在含有疏水处理粉体的油包水体系中加入适量棕榈酰胺丙基三甲基氯化铵可以使体系的黏度降低,油水两相界面张力降低,乳液的乳化颗粒变小,稳定性增加。因此,通过使用棕榈酰胺丙基三甲基氯化铵,提供了一种解决低黏度油包水体系稳定性的方便有效的新方法。该方法在粉底液、防晒乳等化妆品配方中具有广泛的应用价值。     

瓜尔胶的化学改性

简要介绍了瓜尔胶的结构及其化学改性的原理和方法;综述了国内外瓜尔胶化学改性的研究工作;详细介绍了非离子瓜尔胶、阳离子瓜尔胶、阴离子瓜尔胶、羟烷基阴离子瓜尔胶和羟烷基阳离子瓜尔胶以及两性瓜尔胶的合成方法。瓜尔胶通过改性改善了水溶性、大大降低了水不溶物的含量、提高了电解质的兼容性、增加了黏度的稳定性、从而扩大了瓜尔胶的应用领域,使得改性瓜尔胶广泛应用于化妆品、个人护理品、造纸、油田和增稠剂等众多领域。     

纤维素基高分子表面活性剂的合成及性能表征

以聚合度为280的纤维素为原料,通过两步反应,制备了纤维素基高分子表面活性剂纤维素棕榈酰酯硫酸钠,利用红外光谱、动态接触角测定仪、透射电镜和动态光散射等对产物的结构和性能进行了表征.结果表明,该纤维素两亲高分子的临界聚集含量为0.60%(质量分数),对应的表面张力为57 mN/m;当水溶液浓度在临界聚集含量附近时,即水溶液的质量分数由0.5%增大到1.0%,胶束的平均粒径由388.0 nm增大到549.7 nm,此时表面活性剂分子已不断聚集成胶束或胶团;此外该类表面活性剂还具有高分子特有的流变性.     

白芨-丹皮酚包合物在化妆品中的应用研究

化妆品正在形成天然化和功能化的新趋势。“组分天然化”和“回归大自然”的呼声已成为世界化妆品工业的潮流。当今国际化妆品的品位已经由天然成分所占的比例来决定,高档化妆品无一不是以其产品化学成分含量少为荣。开发中药白芨-丹皮酚包合物作为天然功能组分不仅会有很好的化妆品市场前景,同时,还将探明白芨-丹皮酚这种纯天然保湿成膜剂和抗菌剂进一步应用于医药品、日化产品甚至食品工业等领域的应用价值。     

Oxidative Stability of Rice Bran Wax Oleogels and an Oleogel Cream Cheese Product

Recently, a number of publications demonstrated the successful applications of oleogels (OG) (liquid oils gelled through organogelators) in food products. Although many highlighted the health benefits of OG, potential negative impacts of thermal processing during oleogelation on nutrition and flavor quality of the OG‐based food are not fully studied. Hence, in this study, an oleogel‐cream‐cheese (OCC) product was formulated and the effects of OG processing on the oil's oxidative stability and the tocopherol content were investigated. The OG system used in the cheese product was prepared with high‐oleic soybean oil (HOSO) and rice bran wax. An ungelled cream‐cheese sample (UGCC) and two commercial cream‐cheese products were used as controls. Although high‐performance liquid chromatography data analysis showed a lower total tocopherol content in OG samples compared to HOSO, the samples’ α‐tocopherol content remained comparable. No significant differences were observed between the total tocopherol contents of OCC and UGCC cheese products, and the amount of all three‐tocopherol isomers remained constant during 14 days of storage. Although oxidation analysis showed more volatile compounds in OG samples compared to HOSO, there was only a minor difference in the volatile content between the OCC and UGCC samples. The results show minimal degradation of vegetable OG due to the thermal processing and storage that may help their potential application in dairy products.     

含Co介孔分子筛的合成与稳定性研究

两步法进行含Co介孔分子筛的合成,采用XRD,FT-IR,TPR,TEM,N2吸附-脱附等方法对样品的物化性能进行表征结果表明:合成出了具有介孔结构的CoMCM-41,550℃焙烧可以将模板剂有效去除并不影响介孔结构,CoMCM-41的比表面积大于700m2/g,孔径分布在3.4～4.5 nm范围内.650℃热处理3 h或100℃水热处理5 d后CoMCM-41的比表面、孔径和孔体积变化较小,表明CoMCM-41的热稳定性和水热稳定性较好.     

辣椒红色素在化妆品中的稳定性研究

通过对辣椒红色素在化妆品体系中的影响因素进行考察,研究了其溶解度、光照、温度、pH、氧化剂、还原剂、金属离子、化妆品常用防腐剂、乳化剂、香精及UVA/UVA紫外光稳定剂以及化妆品制备工艺等条件的影响,得到了色素在不同条件下的稳定性变化程度和规律。结果表明,辣椒红色素在非极性较大的植物性油脂中溶解度和稳定性较好;色素对热稳定,耐酸碱（pH为4-11为宜）,但对太阳光不稳定;防腐剂、香精和低浓度氧化剂对色素影响较小,还原剂有助于提高其稳定性;金属离子Na^＋、K^＋、Ca^2＋和Zn^2＋对辣椒红色素无影响,Al^3＋、Cu^2＋、Fe^3＋、Ba^2＋、Mg^2＋和Pb^2＋等金属离子影响色素稳定性;乳化剂和UVA/UVB紫外光稳定剂对色素具有保护作用;化妆品制备工艺对色素稳定性产生直接影响,主要表现在O/W乳化体系。     

Synthesis and solution properties of novel nonionic functional polyurethane surfactants

A series of novel nonionic functional polyurethane surfactants were synthesized by the polycondensation of 2,4‐toluene diisocyanate with poly(propylene oxide) (weight‐average molecular weight = 400, 1000, or 2000) and monoallyl‐end‐capped poly(ethylene oxide). The chemical structure of the polyurethane surfactants was determined by Fourier transform infrared and ¹H‐NMR, and the effects of the concentration, salt, rest time, and temperature on the surface tension were investigated. These polymeric surfactants exhibited excellent surface activity. Sample III, which was synthesized with monoallyl‐end‐capped poly(ethylene oxide) (number‐average molecular weight = 1000), poly(propylene oxide) (number‐average molecular weight = 2000), and tolylene diisocyanate, could reduce the surface tension to 37.6 mN/m at a concentration of 0.06 mol/L at 25°C. All polyurethane surfactants synthesized in this study had low critical micelle concentrations (ca. 10^?4 to 10^?5 mol/L) and could reduce the surface tension even at very low concentration levels. Moreover, the surface tension decreased with an increase in the temperature or the concentration of the polyurethane surfactants. The addition of salt resulted in a decrease in the surface tension, and it took some time for the polyurethane surfactants to reach a constant surface tension value. UV spectra were found to be very useful for determining the critical micelle concentration. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2956–2962, 2006     

海藻糖合成双酶体系酶性质及酶反应条件的研究

通过对自筛出的一株微球菌 (Microccusroseus)进行海藻糖合成酶的性质及海藻糖合成的酶反应条件的研究 ,建立了使用粗酶不经纯化 ,直接进行酶反应的工艺流程 ,此工艺有可能进一步降低海藻糖的成本。研究得到了酶反应的一系列优化条件 :2 0 %细胞悬液 ,2 5℃下用 3 %甲苯处理 1h ;然后在 1 0 0mmol/L缓冲液中 ,pH值 8 0、30℃下与 5 %淀粉液化液进行酶反应2 4h ,得到海藻糖转化率达 75 %。研究了该酶体系的性质 ,发现该反应体系不存在底物和产物抑制 ,但存在对其产生抑制的金属离子 ,同时发现海藻糖对该酶体系有异常的激活作用     

乳液

描述了当今制作护肤品用的乳液类型及其加工条件和不稳定因素等。概括地介绍了乳液的种类以及乳液的配制,同时还简要地介绍了评价乳液质量的方法和提高乳液稳定性的一些措施。     

Amphiphilic polysilane with poly(ethylene oxide) side chains

The synthesis of an amphiphilic polysilane with poly(ethylene oxide) grafted segments (PS-g-PEO) through the addition of an allyl-terminated poly(ethylene oxide) (AT-PEO) to poly[diphenylsilane-co-methyl(H) silane] (PSH) in a homogeneous system and using catalyst platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane is reported The process involves the activation of the polymer by microwave irradiation as a preliminary stage with the view to perform the subsequent addition stage at room temperature, when side reactions are prevented. The PS-g-PEO structure was characterized by NMR, FT-IR spectral analysis and GPC methods. The amphiphilic properties were estimated by comparison of the water sorption isotherms of the PS-g-PEO copolymer with those of the component segments. The core-shell micellization in water and the morphological aspects of the self-assembled structures were investigated by DLS and SEM. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Small‐Molecule Inhibitors of AF6 PDZ‐Mediated Protein–Protein Interactions

PDZ (PSD‐95, Dlg, ZO‐1) domains are ubiquitous interaction modules that are involved in many cellular signal transduction pathways. Interference with PDZ‐mediated protein–protein interactions has important implications in disease‐related signaling processes. For this reason, PDZ domains have gained attention as potential targets for inhibitor design and, in the long run, drug development. Herein we report the development of small molecules to probe the function of the PDZ domain from human AF6 (ALL1‐fused gene from chromosome 6), which is an essential component of cell–cell junctions. These compounds bind to AF6 PDZ with substantially higher affinity than the peptide (Ile‐Gln‐Ser‐Val‐Glu‐Val) derived from its natural ligand, EphB2. In intact cells, the compounds inhibit the AF6–Bcr interaction and interfere with epidermal growth factor (EGF)‐dependent signaling.     

新型介孔分子筛的合成与性能表征

利用天然矿物钾长石作为硅铝源前驱体,采用一步晶化法合成出含有NaX型沸石基本结构单元的新型介孔分子筛。采用XRD,N2吸附-脱附曲线、红外光谱(FTIR)、固体核磁共振、SEM等测试方法表征了样品的结构特征和性能。研究表明：所合成的材料具有介孔分子筛的结构特征,孔壁含有NaX型沸石初级和二级结构单元(共享氧原子的[SiO4]和[AlO4]四面体及双六元环);样品的粒度为0．3～0．5μm;其比表面积为777m^2／g;平均孔径为3．2nm,孔壁厚度为1．7nm。固体核磁共振(^27Al MAS NMR)表明：样品经高温煅烧以后骨架中没有脱铝现象出现;TEM观察显示：样品从侧面看为较好的指纹状,正面则为典型的六方孔道排列,即孔口为六方形的蜂窝状结构。合成的样品具有更好的水热稳定性能。     

化妆品中香料的研究进展

综述了化妆品中动物性天然香料和植物性天然香料的分类、成分和来源。详细叙述了天然香料的提取分离技术和合成香料的制备方法。提出了化妆品中香料目前存在的主要问题和发展前景。     

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。