Human Islet Microtissues as an In Vitro and an In Vivo Model System for Diabetes

Loss of pancreatic β-cell function is a critical event in the pathophysiology of type 2 diabetes. However, studies of its underlying mechanisms as well as the discovery of novel targets and therapies have been hindered due to limitations in available experimental models. In this study we exploited the stable viability and function of standardized human islet microtissues to develop a disease-relevant, scalable, and reproducible model of β-cell dysfunction by exposing them to long-term glucotoxicity and glucolipotoxicity. Moreover, by establishing a method for highly-efficient and homogeneous viral transduction, we were able to monitor the loss of functional β-cell mass in vivo by transplanting reporter human islet microtissues into the anterior chamber of the eye of immune-deficient mice exposed to a diabetogenic diet for 12 weeks. This newly developed in vitro model as well as the described in vivo methodology represent a new set of tools that will facilitate the study of β-cell failure in type 2 diabetes and would accelerate the discovery of novel therapeutic agents.     

Novel microencapsulated curing accelerator for prolonging shelf life of epoxy resin composition

A novel micron‐sized microencapsulated curing accelerator, imidazole (Im), particles, was first prepared by an ultrasound‐assisted dispersing and spray‐drying method and can significantly prolong the shelf life of epoxy resin‐based microelectronic packaging material. The shell of the encapsulated particles was made from ladderlike copoly(phenyloctyl silsesquioxane) (Ph‐Oct‐T), which was synthesized by a “stepwise coupling polymerization” method. Its softening or flowing temperature can be adjusted by changing the composition. Carbon tetrachloride (CCl₄) was chosen as both a solvent of the capsular material Ph‐Oct‐T and a suspending/precipitating agent of the fine Im particles. Subsequently, the solution containing Ph‐Oct‐T and suspended Im particles was treated by a spray‐drying process to produce the microencapsulated curing accelerator, Im particles, whose size and appearance was observed by scanning electronic microscopy (SEM). A greatly improved shelf life of the epoxy resin composition containing this microencapsulated curing accelerator was exhibited by curing tests and DSC measurements. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 873–878, 2002     

Convective heat transfer characters of nanoparticle enhanced latent functionally thermal fluid

The latent heat of the microencapsulated phase change material (MPCM) increases the effective thermal capacity of latent functionally thermal fluid. However, researchers found that the heat transfer performance of such fluids was diminished due to the reduction of the low thermal conductivity of MPCM. For this reason, the nanoparticle enhanced latent functionally thermal fluids were formulated and the heat transfer behaviors of these fluids in a vertical circular tube at the laminar regime were conducted. The result showed that slurries containing 0.5% TiO₂ nanoparticles by mass and 5%–20% MPCM by mass exhibited improved heat transfer rates in comparison with the conventional latent functionally thermal fluid and that the enhancement increased with the increasing MPCM concentration and up to 18.9% of the dimensionless wall temperature was reduced. Supported by the National Natural Science Foundation of China (Grant No. 50076020)     

一种丙酮酸乙酯微囊的制备方法

对丙酮酸乙酯进行微囊化研究,经过对比丙酮酸乙酯的包埋率确定最适的选材及条件,并对其各项性能指标进行测定。对制备的丙酮酸乙酯微囊进行喷雾干燥,得到丙酮酸乙酯微囊粉末。实验结果表明,最适壁材组合是阿拉伯胶与Hi-cap 100,壁材与水的最佳质量比例是1.5∶1,最佳喷雾干燥条件进风口温度为160℃,出风口温度为80℃。经过高效液相色谱检测丙酮酸乙酯微胶囊粉末包埋量29.4%,包埋率98%,微囊粉末表面光滑,无塌陷无裂缝,微囊符合要求。     

微胶囊相变材料的制备及应用

微胶囊相变材料是将微胶囊技术应用于相变材料而形成的新型复合相变材料,其直径为2~1000μm,它能够在10~80°C温度范围内,吸收或放出100~200 J/g的热量,而且在吸、放热量的过程中,温度几乎不发生变化。就微胶囊相变材料的特性、结构组成、制备方法和应用领域分别进行了综述。     

Investigation of energy transportation capability of a phase change slurry through a cold storage‐cooling coil system

Microencapsulated phase change materials slurries (MEPCM slurries) have the advantage that they can be used as heat transport and storage medium, and therefore provide improved continuity of energy transport. Energy transportation capability of a MEPCM slurry based on Rubitherm RT6 through a cold storage‐air handling system was investigated for various concentrations and pump powers. The transport properties of the MEPCM have been identified. The optimum concentration for maximum energy transportation capability and energy transportation effectiveness of the system has been found. This investigation is intended for determination of the optimum concentration of MEPCM slurry for an air conditioning system that uses MEPCM slurry as a secondary cooling medium directly into air handling units and stored for load shifting. Copyright © 2009 John Wiley & Sons, Ltd.     

Mechanisms of Beta-Cell Apoptosis in Type 2 Diabetes-Prone Situations and Potential Protection by GLP-1-Based Therapies

Type 2 diabetes (T2D) is characterized by chronic hyperglycemia secondary to the decline of functional beta-cells and is usually accompanied by a reduced sensitivity to insulin. Whereas altered beta-cell function plays a key role in T2D onset, a decreased beta-cell mass was also reported to contribute to the pathophysiology of this metabolic disease. The decreased beta-cell mass in T2D is, at least in part, attributed to beta-cell apoptosis that is triggered by diabetogenic situations such as amyloid deposits, lipotoxicity and glucotoxicity. In this review, we discussed the molecular mechanisms involved in pancreatic beta-cell apoptosis under such diabetes-prone situations. Finally, we considered the molecular signaling pathways recruited by glucagon-like peptide-1-based therapies to potentially protect beta-cells from death under diabetogenic situations.     

Influence of homogenisation conditions and drying method on physicochemical properties of dehydrated emulsions containing different solid components

Dehydrated o/w emulsions containing sodium caseinate and lactose (sample 1), and gelatine, sucrose and maltodextrin (DE 10) (sample 2) were used to study the influence of homogenisation conditions – homogenisation pressure (15 and 70 MPa) and number of passes (1 and 2) – and the drying method – spray‐drying vs. freeze‐drying – on physicochemical parameters, including oil microencapsulation efficiency (ME), oil droplet size in reconstituted emulsions, water activity, glass transition temperature, powder bulk density and time for emulsion reconstitution in water. Results showed that small and uniform oil droplets attained with increased homogenisation pressure were not sufficient for high oil encapsulation. The permeability of the solid wall to the extraction solvent appeared to be the dominant factor, and this may increase with homogenisation pressure. With the exception of oil droplet size in sample 1 and ME in sample 2, the drying method exerted larger changes in the physicochemical parameters studied than the homogenisation pressure. For sample 2, significant changes in the ME were not observed between the freeze‐dried and spray‐dried samples, even though a great emulsion destabilisation was observed in the reconstituted emulsion of the latter.     

相变储能微胶囊壁材传热强化措施研究进展

从无机壁材（碳酸钙、二氧化钛）、无机碳材料（氧化石墨烯、碳纳米管、复合碳材料）改性、纳米材料（纳米氧化铝、纳米二氧化钛和其他纳米材料）改性等3个方面综述了相变储能微胶囊壁材增强热导率方面的研究进展,分析了各个方法的特点,为今后相变储能微胶囊导热增强的改性方向及措施提供了理论指导。     

建筑相变材料的封装技术

概述了建筑相变材料的发展历程及研究现状。在对储能机理分析的基础上,归纳了建筑相变材料的性能要求。介绍了目前研制建筑相变材料用到的各类主要封装技术以及这些封装技术的优缺点。在此基础上指出建筑相变材料存在的问题,预测了发展趋势,最后进行了总结。