Preparation and characterization of copolymerized aminopropyl/phenylsilsesquioxane microparticles

Poly(aminopropyl/phenyl)silsesquioxane (PAPSQ) microparticles with approximately 350 nm diameter were conveniently synthesized from the hydrolytic co-condensation of γ-aminopropyltriethoxysilane (APS) and phenyltriethoxysilane (PTES) in the presence of ethanol and water (EtOH-H₂O) by using tetramethylammonium hydroxide (TMAOH) catalysts. Hybrid compositions of PAPSQ containing both aminopropyl and phenyl groups were confirmed from FT-IR, ²⁹Si CP-MAS NMR, TGA. XRD patterns indicated that a certain ordered structure existed in PAPSQ molecules. Contents of amino groups of PAPSQ were determined by elemental analysis and back titration. Specific surface areas were evaluated through BET method. PAPSQ offers the potential utility as building blocks for diverse and novel organic/inorganic materials.     

化学转化法制备磁性阳离子交换树脂的研究

本文通过化学转化法即化学共沉淀法，分别研究了强酸性和弱酸性阳离子交换树脂的磁转化对相应所得树脂的磁性的影响，制得了磁性毫米级和微米级粒径的强酸性，弱酸性阳离子交换树脂。所得磁性树脂有磁性强，磁性物质分布均匀而且稳定，并保持树脂的原有特性。     

Microdistribution of copper-carbonate and iron oxide nanoparticles in treated wood

Aqueous dispersions of copper-carbonate nanoparticles and microparticles have just begun to be exploited commercially for the preservative treatment of wood. The success of the new systems will depend, in part, on the uniform distribution of the preservative in wood and the ability of copper to penetrate cell walls. We examined the distribution of copper in wood treated with a nano-Cu preservative. Copper particles are not uniformly distributed in treated wood, but they accumulate in voids that act as the flow paths for liquids in wood. Particles are deposited on, but not within cell walls. Nevertheless, elemental copper is present within cell walls, but at a lower level than that in wood treated with a conventional wood preservative. These findings suggest that nano-Cu preservatives are able to deliver bioactive components into wood cell walls even though the majority of copper particles are too large to penetrate the cell wall’s nanocapillary network.     

微颗粒X射线荧光强度MCNPX模拟与WDXRF实验

为研究样品微颗粒在X射线荧光(XRF)分析中对测量结果的影响,运用蒙特卡罗模型MCNPX对X射线荧光仪进行建模,研究了样品颗粒粒径对X射线荧光特征峰强度、峰总比和源峰探测效率的影响,并设计波长色散X射线荧光光谱法(WDXRF)分析实验对模拟结果进行了检验。结果表明：对于样品微颗粒X射线荧光强度与粒径尺寸的关系,MCNPX模拟值与理论计算值保持一致;MCNPX模拟结果与WDXRF实验结果存在一定差异,这取决于MCNPX模型对待测样品状态的假设与实际情况存在一定的差异性;运用样品粉碎、研磨至小颗粒并进行压片处理的办法,可使WDXRF实测结果尽可能的减小与MCNPX理论模拟结果的差异性;在待测样品的颗粒粒径达到一定尺寸时,其峰总比、源峰探测效率、特征峰X射线荧光计数均趋于稳定值;颗粒粒径在某一特定尺寸范围之内,颗粒度效应的影响不容忽视;除此之外,颗粒度效应的影响基本可以忽略。论文充分考虑了待测样品颗粒粒径对XRF分析结果的影响,为减小因颗粒度效应引起分析结果的不确定性提供了一种可行的研究思路,该方法也可为X射线分析的生产实践提供一定的技术参考。     

Production of microscale particles from fish bone by gas flow assisted laser ablation

Recycled wastes from fish and seafood can constitute a source of precursor material for different applications in the biomedical field such as bone fillers or precursor material for bioceramic coatings to improve the osteointegration of metallic implants.In this work, fish bones have been used directly as target in a laser ablation system. A pulsed Nd:YAG laser was used to ablate the fish bone material and a transverse air flow was used to extract the ablated material out of the interaction zone. The particles collected at a filter were in the micro and nanoscale range. The morphology as well as the composition of the obtained particles were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). The results reveal that the composition of the analyzed particles is similar to that of the inorganic part of the fish bone.     

Release properties of chemical and enzymatic crosslinked gelatin-gum Arabic microparticles containing a fluorescent probe plus vetiver essential oil

Oil-containing gelatin-gum Arabic microparticles were prepared by complex coacervation followed by crosslinking with glutaraldehyde or transglutaminase. A fluorescent mixture, khusimyl dansylate (KD) as the fluorescent compound mixed to the vetiver essential oil, was used as oil model. The effect of the type of crosslinking of the coacervated gelatin-gum Arabic membrane, the physical state of microparticles, wet or freeze-dried and the type of release media, aqueous with surfactants, Sodium Dodecyl Sulphate (sds) or Tween 80 (tw) and anhydrous ethanol as organic media on the release rate of the KD from the microparticles, was experimentally investigated.It was shown that the oil was dispersed uniformly throughout the microparticles and the chemical crosslinked microparticles were more resistant to swelling, presenting smaller sizes after hydration. Also the crosslinking effect, transglutaminase or glutaraldehyde, could be confirmed by the integrity of the crosslinked gelatin-gum Arabic microparticles after incubation in the aqueous sds media, compared to complete dissolution of the uncrosslinked microparticles in this media.The cumulative fluorescent KD release from the gelatin-gum Arabic microparticles decreased in the following order of dissolution media: anhydrous ethanol > tw > sds and the wet microparticles have shown a faster KD release than freeze-dried ones. A mathematical model was used to estimate the diffusion coefficient (D). The chemically crosslinked gelatin-gum Arabic microparticles ensured a pronounced retard effect in the KD diffusion, presenting a D varying from 0.02 to 0.6 × 10⁻¹¹ cm²/s, mainly in an aqueous media, against D varying from 1.05 to 13.9 × 10⁻¹¹ cm²/s from the enzymatic crosslinked microparticles.     

聚己内酯微粒的生物降解行为

由于微包囊药物制剂具有降低药物毒副作用、防止药物失活、减少服药次数以及靶向给药的效果,从而既可提高病灶部位的药物浓度,又可减小对机体其它部位的损伤,因此成为较理想的药物释放体系,以至目前在药物释放体系中,微包囊药物释放体系得到了广泛的应用．生物降解性高分子是理想的药物包裹材料,由于它在药物释放完毕后可以在体内降解、而后被机体代谢或吸收,不需再手术取出,因此,用高分子微包囊药物释放体系治疗癌症等疑难病症正在成为国际上共同的研究热点［１］．聚己内酯（ＰＣＬ）是兼具良好力学性能和药物通透性能的生物降解…     

静电喷雾法制备聚膦腈微球

用静电喷雾法制备了粒径窄分布的甘氨酸乙酯-苯丙氨酸乙酯取代聚膦腈的微球.主要探讨了溶剂、溶液浓度、流速、喷射电压及接收距离对微球形貌和粒径的影响.微球的表面形貌与溶剂性质和聚合物溶液浓度密切相关,微球粒径受聚合物溶液流速的影响比较显著,随流速增大粒径呈单调上升趋势.结果显示对于[η]=0.1 dL/g的(甘氨酸乙酯)0.3(苯丙氨酸乙酯)0.7取代聚膦腈,以0.25 g/mL的四氢呋喃溶液进行静电喷雾,可获得粒径分布窄(1~2μm)且近球形的微粒,其工艺条件可进一步用于载药聚膦腈微球的制备和控制释放研究.     

Encapsulation,protection, and release of hydrophilic active components: Potential and limitations of colloidal delivery systems

There have been major advances in the development of edible colloidal delivery systems for hydrophobic bioactives in recent years. However, there are still many challenges associated with the development of effective delivery systems for hydrophilic bioactives. This review highlights the major challenges associated with developing colloidal delivery systems for hydrophilic bioactive components that can be utilized in foods, pharmaceuticals, and other products intended for oral ingestion. Special emphasis is given to the fundamental physicochemical phenomena associated with encapsulation, stabilization, and release of these bioactive components, such as solubility, partitioning, barriers, and mass transport processes. Delivery systems suitable for encapsulating hydrophilic bioactive components are then reviewed, including liposomes, multiple emulsions, solid fat particles, multiple emulsions, biopolymer particles, cubosomes, and biologically-derived systems. The advantages and limitations of each of these delivery systems are highlighted. This information should facilitate the rational selection of the most appropriate colloidal delivery systems for particular applications in the food and other industries.     

Electrochemical Quartz Crystal Microbalance Study of FeS Particles Attached to Au Surface

Electrochemical quartz crystal microbalance (EQCM) measurements were employed for studying of the redox processes of FeS microparticles immobilized on Au electrode surface in contact with aqueous solutions of NaCl, NaCl‐NaHCO₃, and NaCl‐Na₂S. The objective was to shed light on the complexity of the iron sulfide electrochemistry. For the sake of comparison electrochemical behavior of FeS suspension was also investigated on the paraffin‐impregnated graphite (PIGE) and hanging mercury drop (HMDE) electrodes. In order to understand the complex nature of the redox transformations of FeS, Mohr‐salt was dissolved in NaCl and NaCl‐NaHCO₃ solutions, respectively, and the deposition‐dissolution processes occurring in the course of the reduction of Fe(II) and reoxidation of Fe(0) were also monitored.