尼克酰胺对白介素-1β损伤的离体大鼠胰岛细胞的保护作用

目的 观察尼克酰胺(NA)对白细胞介素-ip(IL-1(3)诱导的胰岛细胞损害的保护作用。方法 应用体外单层培养的大鼠胰岛细胞,分别检测IL-1(3, NA(10, 20 mmol/L)及其联合对胰岛细胞亚硝醆盐生成,肤岛素分泌以及胞内DNA,胰岛素含量和细胞活性的影响。结果 由IL-1β谓导的肤岛細胞亚硝醆盐生成量显著增加,同时胰岛素基础分泌以及葡萄糖刺激的胰岛素释放均明显减少;胰岛细胞内DNA,狹岛素含量及细胞活性（MTT值）均显著下降（P均<0.001);较高浓度及其的NA(20 mmol/1,)能阻断这些抑制作用（P均<0.001);而较低浓度的NA（10 mmol/L)虽不能阻断IL-1β诱导的NO生成对葡萄糖刺激的肤岛素释放的抑制作用,但对IL-lβ介导的其它抑制作用仍呈现保护性故应（P均<0.01)。结论 一氧化氮(NO)虽然参与IL-lβ诱导的胰岛细胞的损害过程,但可能不是唯一的故应分子。NA可能通过包括抑制NO生成等多方面机制,实现对IL-1β诱导的胰岛細胞损害的保护作用。     

高分子材料在微胶囊电泳显示技术中的应用

介绍了微胶囊电泳显示技术的原理、微胶囊电泳显示器件的制备。阐述了高分子材料在制备微胶囊电泳显示材料和器件过程中的应用．重点说明了在这种新型的显示技术中颜料一聚合物复合粒子、微胶囊和塑料晶体管的应用。     

Studies on the possibility of recycling microencapsulated disperse dye‐bath effluents

The volume of water consumed by human beings has increased dramatically in recent years while water supply has remained constant; both demographic growth and the expansion of industrial activity require more water consumption. The textile industry is undoubtedly one of the most pressured industries that need water intensively. Efficient use of water tends to be a crucial subject for the dyeing industry. In this study, melamine resin microcapsules containing pure disperse dyes were prepared by in situ polymerization. The microcapsules were characterized on the basis of structure, morphologies, mean particle size, and size distribution. The dyeing behaviors of microencapsulated disperse dyes (MDDs) were evaluated on polyester fabrics in the absence of auxiliaries. Its effluent can be reused several times after being simply filtered and can be used as solvent for PET fabric scouring. The treated fabrics exhibited satisfactory levelness and fastness properties. MDDs can be used in dyeing PET, without using surfactants, and the effluents can be recycled and reused. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Monitoring the survival of islet transplants by MRI using a novel technique for their automated detection and quantification

Object  There is a clinical need to be able to assess graft loss of transplanted pancreatic islets (PI) non-invasively with clear-cut quantification of islet survival. We tracked transplanted PI in diabetic mice during the early post-transplant period by magnetic resonance imaging (MRI) and quantified the islet loss using automatic segmentation technique. Materials and methods  Magnetically labeled islet iso-, allo- and xenografts were injected into the right liver lobes. Animals underwent MRI scanning during 14 days after PI transplantation. MR images were processed using custom-made software, which automatically detects hypointense regions representing PI. It is based on morphological top-hat and bottom-hat transforms. Results  Manually and automatically detected areas, corresponding to PI, differed by 4% in phantoms. Signal loss regions due to PI decreased comparably in all groups during the first week post transplant. Throughout the second week post-transplant, the signal loss area continued in a steep decline in case of allografts and xenografts, whereas the decline in case of isografts slowed down. Conclusion  Automatic segmentation allows for the more reproducible, objective assessment of transplanted PI. Quantification confirms the assumption that a significant number of islets are destroyed in the first week following transplantation irrespective of allografts, xenografts or isografts.     

Microstructure and thermal conductivity of fully ceramic microencapsulated fuel fabricated by spark plasma sintering

Fully ceramic microencapsulated pellet (FCM), consisting of tristructural isotropic (TRISO) particles embedded in silicon carbide (SiC) matrix, was fabricated using spark plasma sintering. The parameters affecting the densification of SiC matrix were first investigated, and then FCM pellets were prepared using TRISO particles with/without outer pyrolytic carbon (OPyC) layer. Effects of thermal exposure on the TRISO particles during SPS were evaluated. In addition, the thermal condcutvitities of FCM pellet, as well as the SiC matrix, were measured using laser flash. It was revealed that the TRISO particles with OPyC layers significantly lower the thermal conductivity of FCM pellet. Based on Maxwell‐Eucken model, the predicted effective thermal conductivities of TRISO particles with/without OPyC layers were 14.4 W/m K and 25.2 W/m K, respectively. Finite elements simulation indicated that the SiC layer in TRISO particle plays a dominant role on the thermal conductivity of FCM. The presence of OPyC layers would generate gaps/porous SiC near the interface and resist the heat flows, leading to a lower thermal conductivity of FCM.     

新剂型香精及其包埋技术的应用

新剂型香精区别于传统液体香精的地方在于采用了包埋技术,将各种保护性壁材以不同方式和过程包覆香精,从而保护香精,赋予香精更优越的性能。文中介绍了五种新剂型香精:分子胶囊香精、纳米胶囊香精、微胶囊香精、颗粒香精、爆珠香精,并阐述了其制备方法及优缺点。     

基于相变微胶囊悬浮液的太阳能光伏热系统的研究进展

在太阳能光伏热系统中,光伏电池温度过高会导致太阳能发电效率下降。相变微胶囊悬浮液(MEPCMS)是一种潜热型功能性流体,将其作为冷却介质用于太阳能光伏热系统可以有效降低光伏电池温度,提高系统的能量利用率。针对相变微胶囊易泄露、导热性差等问题提出了改性方法,使其具有光热转换功能并提升了综合性能。基于性能评价指标分析了太阳能光伏热系统性能的影响因素。结果发现,流速、浓度和太阳辐照量是影响MEPCMS在太阳能光伏热系统中换热性能的关键因素。适当增加MEPCMS浓度和流速能提高工质的换热性能,在降低光伏板温度的同时增加太阳辐照量和系统热电产量,但需结合太阳辐照量大小合理匹配工质的浓度和流速。未来研究方向可集中在提升MEPCMS在太阳能光伏热系统中的换热性能、探究运行参数和太阳辐照量之间的匹配关系、优化集热器结构、利用其蓄热性解决太阳能间歇性等方面。     

Recommendations for the viability assessment of probiotics as concentrated cultures and in food matrices

Due to the fact that probiotic cells need to be alive when they are consumed, culture-based analysis (plate count) is critical in ascertaining the quality (numbers of viable cells) of probiotic products. Since probiotic cells are typically stressed, due to various factors related to their production, processing and formulation, the standard methodology for total plate counts tends to underestimate the cell numbers of these products. Furthermore, products such as microencapsulated cultures require modifications in the release and sampling procedure in order to correctly estimate viable counts. This review examines the enumeration of probiotic bacteria in the following commercial products: powders, microencapsulated cultures, frozen concentrates, capsules, foods and beverages. The parameters which are specifically examined include: sample preparation (rehydration, thawing), dilutions (homogenization, media) and plating (media, incubation) procedures. Recommendations are provided for each of these analytical steps to improve the accuracy of the analysis. Although the recommendations specifically target the analysis of probiotics, many will apply to the analysis of commercial lactic starter cultures used in food fermentations as well.     

微胶囊化甜橙油在高温下的释放

对采用β- 环糊精法和乳化喷雾干燥法所制备微胶囊化甜橙油在温度 10 0、12 0、14 0、16 0、180和 2 0 0℃下的释放进行了研究 ,利用Avrami’s公式分析了微胶囊化甜橙油在高温下的释放。结果表明 ,2种不同方法所制备的微胶囊化甜橙油由于其制备原理上的不同而使其在高温下的释放存在着一定的差异。     

溶胶凝胶法改性乙基纤维素微胶囊红磷

目的开发一种绿色环保、简便高效的微胶囊红磷制备及改性工艺。方法以无水乙醇为溶剂,水为非溶剂,乙基纤维素为囊壳材料,采用相分离法制备乙基纤维素微胶囊红磷(ECRP)。在此基础上,以正硅酸乙酯(TEOS)作为改性剂,采用溶胶凝胶法制备Si O2/EC复合囊壳微胶囊红磷(Si-ECRP)。通过改变TEOS的添加量制备多组Si-ECRP样品,对样品进行形态表征及性能测试,探究最佳工艺条件。结果采用相分离法制备了ECRP,样品包覆效果良好,包覆率为86.5%。10 d后,ECRP的吸湿率降至6.8%,相对于红磷24%的吸湿率,具有明显改善。ECRP的热稳定性和安定性提高,着火点上升至300℃,摩擦感度降至34%。随着TEOS添加量的增加,三组Si-ECRP囊壳结构由Si O2/EC复合结构向SiO_2-EC双层包覆结构过渡。选取1m LTEOS添加量作为最佳工艺条件,此时囊壳呈复合结构,样品包覆率达94.2%,着火点较ECRP样品提高100℃,摩擦感度较ECRP下降14%,低至20%,具有更优异的使用性能。结论采用相分离法制备ECRP样品,整个工艺流程在常温、中性条件下进行,原料绿色环保,工艺简便高效。利用乙基纤维素的成壳机理,简化了溶胶凝胶法改性工艺,制备了SiO_2/EC复合囊壳结构,微胶囊红磷的安定性能得到进一步提升。