Surfactant Concentration,Antioxidants, and Chelators Influencing Oxidative Stability of Water‐in‐Walnut Oil Emulsions

Effects of surfactant concentration, antioxidants with different polarities, and chelator type on the oxidative stability of water‐in‐stripped walnut oil (W/O) emulsions stabilized by polyglycerol polyricinoleate (PGPR) were evaluated. The formation of primary oxidation products (lipid hydroperoxides) and secondary oxidation products (hexanal) decreased with increasing PGPR concentrations (0.3–1.0 wt% of emulsions). Excess surfactant might solubilize lipid hydroperoxides out of the oil–water interface, resulting in the decreased lipid oxidation rates in W/O emulsions. At concentrations of 10–1000 μM, the polar Trolox demonstrated concentration‐dependent antioxidant activity according to both hydroperoxide and hexanal formation. The antioxidant efficiency of the non‐polar α‐tocopherol was slightly reduced at the higher range of 500–1000 μM based on hydroperoxide formation. Both ethylenediaminetetraacetic acid (EDTA) and deferoxamine (DFO) at concentrations of 5–100 μM reduced the rates of lipid oxidation at varying degrees, indicating that endogenous transition metals may promote lipid oxidation in W/O emulsions. EDTA was a stronger inhibitor of lipid oxidation than DFO. These results suggest that the oxidative stability of W/O emulsions could be improved by the appropriate choice of surfactant concentration, antioxidants, and chelators.     

反相微乳液制备AgCl/PMMA复合胶乳及其抗菌性能

以聚乙二醇辛基苯基醚(OP)为表面活性剂,甲基丙烯酸甲酯(MMA)为油相构筑的反相微乳液合成纳米Ag Cl粒子,然后通过微乳液聚合制备Ag Cl/PMMA复合胶乳。利用紫外-可见吸收光谱(UV-vis)和透射电镜(TEM)研究微乳液中表面活性剂浓度(cop)、水相中盐浓度(csalt)对纳米Ag Cl粒子的形成及形貌影响,结果发现合成的Ag Cl粒子近似球状,粒径在5 nm左右;在反相微乳液中随cop、csalt的增加,形成的纳米Ag Cl粒子数增多、平均粒径有所减小。Ag Cl/PMMA复合胶乳对大肠杆菌表现出明显的抗菌活性。通过反相微乳液及其聚合技术制备包含有纳米Ag Cl的复合胶乳,方法简便、易于放大,所制备的Ag Cl/PMMA复合胶乳作为抗菌剂具有良好的应用前景。     

Basic Mandarin color terms

In comparative studies of basic color terms of various ethnic groups, Berlin and Kay found that the number of basic color terms used is greater, the more highly developed a culture becomes and vice-versa (Berlin and Kay 1969: 16). According to their thesis, peoples possessing the most highly developed cultures use 11 basic color terms, or the equivalents of white, black, red, yellow, green, blue, brown, orange, purple, pink, and gray. These 11 color terms are found in Japanese, Korean, and Cantonese. However, as only six are found in Mandarin, Mandarin was assigned to a lower stage of cultural development. This is incorrect. In an effort to prove this assertion, this author has conducted numerous studies. Based on research of Mandarin color terms and mapping response, this study attempts to prove that Mandarin has long contained the 11 basic color terms noted by Berlin and Kay. However, after conducting a mapping response study, it was discovered that the Berlin-Kay color set (i.e., the Berlin-Kay-MacLaury Munsell set) is inadequate for examining low saturation basic color terms such as he (Br) and cang (grayish BG), the representative colors of which are difficult to fully ascertain. During this study, this author discovered a certain degree of difficulty hindering mutual understanding between Eastern and Western cultures. Consequently, this study seeks to promote a degree of such understanding. © 1997 John Wiley & Sons, Inc. Col Res Appl, 22, 4–10, 1997.     

Complex formation in a ternary system composed of lauroamphoglycinate, oleic acid, and water

The formation of a complex, composed of lauroamphoglycinate (LG), oleic acid (OA) and water, was investigated, and this system was applied to emulsification. The complex was formed in the water-rich area (more than 90% in this system) at a molar ratio of OA to LG from 1 to 3, where two-phase systems of water and the complex existed. The interaction between LG and OA, both in the aqueous solution and at the interface of liquid paraffin dissolving the OA and LG solution, was studied by pH measurements and interfacial tension measurements, respectively. The results implied that LG and OA were linked stoichiometrically, both in aqueous solution and at the interface, and formed complexes. X-ray diffraction patterns and the strong hydrophobicity showed that the equimolar complex composed of LG, OA, and water was a liquid crystal with a reversed hexagonal structure. The reversed hexagonal liquid crystal was capable of solubilizing a certain amount of liquid paraffin in its alkyl group parts while maintaining its hexagonal structure. These results suggest the possibility to prepare a W/O-type emulsion by using the liquid crystal formed by LG, OA, partial liquid paraffin, and water as the continuous phase. The authors could obtain a stable W/O emulsion without coalescence of the water droplets that contained a substantial amount of water (approximately 90%). Furthermore, various types of emulsions, O/W, W/O, W/O/W, could be prepared by changing the ratio of LG and OA.     

基于DSP的数据处理器的设计与实现

利用DSP的内部资源和外设接口,设计基于TMS320F2812、AD转换芯片AD7656和网络芯片W5100的数据处理器,给出了系统硬件结构设计、芯片之间接口电路设计和软件实现方法。实现了对工业现场电压信号和电流信号的实时同步采样,同时对采集到的数据进行相关处理,并利用网络接口将数据发送到PC机进行显示和分析。     

H6P2M09W9O62/Zn(BDC)(Bipy)0.5复合材料催化合成3,4-二氢嘧啶-2(H)酮衍生物

采用水热法分别合成杂多酸H6P2Mo9W9O62及有机金属骨架Zn(BDC) (Bipy)0.5,使用浸渍法合成H6P2Mo9W9O62/Zn(BDC) (Bipy)05复合材料,用该复合材料催化醛、乙酰乙酸乙酯和尿素通过Biginelli反应,乙醇作溶剂,合成6种3,4-二氢嘧啶-2(H)酮衍生物.通过IR、1HNMR、13CNMR确定其结构,通过m.p.确定其纯度.实验结果表明:固定醛用量为0.04 mol,n(醛)∶n(乙酰乙酸乙酯)∶n(尿素)=1∶1.4∶1.5,2.0 wt％ H6P2Mo9W9O62/Zn(BDC)(Bipy)0.5,反应温度为105℃,反应时间为60 min时,产物收率为40.1％～91.5％.     

高效阴离子交换色谱-脉冲安培法测定W135群和Y群脑膜炎球菌多糖中半乳糖和葡萄糖含量

目的采用高效阴离子交换色谱-脉冲安培法(High-performance anion-exchange chromatography with pulsedamperometric detection,HPAEC-PAD)测定W135群和Y群脑膜炎球菌荚膜多糖中半乳糖和葡萄糖的含量,并对该方法进行验证及初步应用。方法多糖蛋白结合物原液的混合液经HCl水解处理后,进样CarboPac PA10柱,以氢氧化钠-醋酸钠梯度流洗,脉冲积分安培检测器检测。筛选样品的水解条件;对HPAEC-PAD法进行专属性、精密性及准确性验证,并进行初步应用。结果确定的样品水解条件为以2 mol/L HCl于85℃处理1 h。载体蛋白破伤风类毒素对检测结果无干扰;重复性、日内精密性和不同操作者之间精密性试验结果的RSD均小于5%;准确性试验中葡萄糖和半乳糖的回收率在90%～110%之间。HPAEC-PAD法测定多糖蛋白结合物原液的多糖含量与传统间苯二酚比色法测定结果相当;成品疫苗中的W135群和Y群多糖含量测定结果符合《A、C、W135、Y群脑膜炎球菌结合疫苗制造及检定规程草案》的规定(均≥4μg/剂)。结论 HPAEC-PAD法专属性、精密性和准确性良好,可用于A、C、W135、Y群脑膜炎球菌结合疫苗中W135群和Y群多糖含量的测定。     

Effect of Cryoprotectant and Freeze-Drying Process on the Stability of W/O/W Emulsions

In order to protect a hydrophilic drug and to prolong its further delivery, the formulation of multiple emulsions could be worthy. However, the double emulsions are not stable, their structure can change, leading to the formation of a single emulsion as the destruction of the system, and the drug can release easily from the globules in liquid state. The freeze-drying technology could be used to produce dry emulsion, the powder form being much more stable. The aim of this work was to study the influence of a cryoprotectant and a freeze-drying process on the stability of W/O/W emulsions. Samples were frozen at two different freezing rate (ν _f  = 0.55°C/min and 1.25°C/min) and successively dried at two different sublimation temperature (T _s  = ? 10°C and ? 20°C). The particle size distributions were measured by granulometer and UV spectrophotometer was performed to investigate the leakage of internal constituent. The glass transition temperature (T _g ) of the double emulsions was analyzed by DSC. The particle sizes became even smaller after freeze drying, except when κ-carrageenan is used as a cryoprotectant. In that case, the particles became aggregated after freeze drying, whatever the process conditions. The mean size is considerably reduced when the globules are diluted at low concentration in glucose and trehalose solution. When the concentration is increased, the size distribution is not significantly affected. The leakage of the internal aqueous phase to the external one during freeze drying was measured as an indicator of the structure stability. It is affected by the nature of the cryoprotectant and the conditions of the freeze-drying process. The leakage of the internal phase was smaller when cycle III (ν _f  = 1.25°C/min, T _s  = ? 10°C) was processed. From our experiments, we suppose that the water transfer from the inner phase to the outer aqueous phase results in the diminution of the globules size in double emulsion. The T _g of the double emulsions diluted with trehalose and glucose were determined at ? 33.8°C and ? 47.1°C. In contrast, the T _g of double emulsion with κ-carrageenan and HES did not appear.     

Preparation and properties of poly(urethane acrylate) (PUA) and tetrapod ZnO whisker (TZnO‐W) composite films

Tetrapod zinc oxide whiskers (TZnO‐Ws) were successfully synthesized via a thermal oxidation method and confirmed using Fourier transform infrared spectroscopy, X‐ray diffraction and scanning electron microscopy. A series of poly(urethane acrylate) (PUA)/TZnO‐W composite films with various TZnO‐W contents were prepared via a UV curing method and their physical properties were investigated to understand their possible use as packaging materials. The morphological, thermal, mechanical, antibacterial and barrier properties of the PUA/TZnO‐W composite films were interpreted as a function of TZnO‐W content. The thermal stability, barrier properties and antibacterial properties of the composite films, which were strongly dependent upon their chemical and morphological structure, were enhanced as the TZnO‐W content increased. The oxygen transmission rate and water vapor transmission rate decreased from 614 to 161 cm³ m^?2 per day and 28.70 to 28.16 g m^?2 per day, respectively. However, the mechanical strength of the films decreased due to the low interfacial interaction and poor dispersion with high TZnO‐W loading. The enhanced barrier properties and good antibacterial properties of the PUA/TZnO‐W composite films indicate that these materials are potentially suitable for many packaging applications. However, further studies are needed to increase the compatibility of polymer matrix and filler. © 2012 Society of Chemical Industry