Investigation of injectable drospirenone organogels with regard to their rheology and comparison to non-stabilized oil-based drospirenone suspensions

The objective of this study was to evaluate organogels as potential injectable drug-delivery systems for drospirenone (DRSP). Recently, studies on organogel characterization with focus on the parenteral injection are rarely to find in the literature. DRSP organogels contained the drug suspended in medium-chain triglycerides and were stabilized by various organogelators. The DRSP organogels were assessed in comparison to non-stabilized DRSP microcrystal suspensions (MCSs). Furthermore, rheological properties of the organogels, in particular the elastic modulus (G′), the complex viscosity (η*) and the elasticity, were evaluated with respect to the long-term stability, syringeability/injectability and in vitro release. DRSP organogels showed significantly improved storage stability compared to non-stabilized MCSs with regard to sedimentation and particle growth. Furthermore, all of the DRSP organogels showed shear-thinning behavior. Thus, ejection from syringes was possible by an autoinjector using 23G needles comparable to non-stabilized MCSs. Nevertheless, DRSP organogels exhibited significantly more sustained drug release than non-stabilized MCSs most likely caused by partial recovery of the organogelator structures at 37?°C after destruction. Consequently, DRSP organogels were evaluated to be superior to conventional non-stabilized MCSs. Silica organogels, which provided the highest elasticity, moderate G' and η* and avoided most efficiently particle growth, are slightly more preferable compared to the other DRSP organogels.     

Use of Nanoindentation,Finite Element Simulations,and a Combined Experimental/Numerical Approach to Characterize Elastic Moduli of Individual Porous Silica Particles

This article describes the use of a combination of experimental nanoindentation and finite element numerical simulations to indirectly determine the elastic modulus of individual porous, micron-sized silica (SiO₂) particles. Two independent nanoindentation experiments on individual silica particles were employed, one with a Berkovich pyramidal nanoindenter tip, the other with a flat punch nanoindenter tip. In both cases, 3D finite element simulations were used to generate nanoindenter load–displacement curves for comparison with the corresponding experimental data, using the elastic modulus of the particle as a curve-fitting parameter. The resulting indirectly determined modulus values from the two independent experiments were found to be in good agreement, and were considerably lower than the published values for bulk or particulate solid silica. The results are also consistent with previously reported modulus values for nanoindentation of porous thin film SiO₂. Based on a review of the literature, the authors believe that this is the first article to report on the use of nanoindentation and numerical simulations in a combined experimental/numerical approach to determine the elastic modulus of individual porous silica particles.     

水解工艺Yb3＋/Al3＋共掺石英玻璃的研制及特性表征

利用四氯化硅(SiCl₄)水解掺杂法结合高 频等离子体粉末熔融技术制备了Yb3＋/Al3＋共掺石英玻璃,并利用 X射 线衍射(XRD)、傅里叶变换红外(FTIR)光谱分析和热膨胀分析等对所制备玻璃样品的结 构特性、物理特性和光谱特 性进行了表征。结果表明,制备的Yb3＋/Al3＋共掺石英玻璃的密度和折 射率值与纯石英玻璃相接近,并且呈现出 较好的玻璃态,其热膨胀系数为2.87×10－6,具有较好的Yb3＋和Al 3＋掺杂均匀性,以及Yb3＋典型的吸 收特性和发射特性,表明采用本文方法制备的Yb3＋/Al3＋共掺石英玻璃 已具备成为大功率激光材料的潜质。     

一维纳米氧化锌的制备及应用研究进展

本文对一维纳米氧化锌的制备方法进行了综述,包括气相法、液相法和模板法;重点讨论了一维纳米氧化锌在太阳能电池、传感器、多功能纺织品以及有机物光催化降解等方面的应用;指出了一维纳米氧化锌制备中存在的问题,并对其后续发展进行了展望.     

聚酰亚胺/SiO_2纳米复合抗原子氧气凝胶的合成与性能

以3,3′,4,4′-联苯四酸二酐(sBPDA)和2,2′-二甲基-4,4′-二氨基联苯胺(DMBZ)为聚合单体,八(氨基苯基)聚倍半硅氧烷(OAPS)为交联剂,SiO2纳米粒子为填料,采用超临界二氧化碳干燥工艺制备了一系列聚酰亚胺(PI)/SiO2纳米复合气凝胶(CPIA-SiO2-0~CPIA-SiO2-7)。研究表明:SiO2纳米粒子的引入对PI气凝胶的耐热性能未产生显著的影响。然而,随着SiO2纳米粒子含量的增加,PI气凝胶的孔隙率从89.6%逐渐降低至79.4%,BET表面积也随之从425.5m2/g降低至380.2m2/g,纳米泡孔孔径分布呈现出变宽的趋势。SiO2的引入显著提高了PI气凝胶的抗原子氧侵蚀能力,含量为7%(质量分数,下同)的PI/SiO2复合气凝胶CPIA-SiO2-7的原子氧侵蚀率(2.6%)仅为不含SiO2气凝胶CPIA-SiO2-0的原子氧侵蚀率(12.3%)的1/5左右。     

液膜电化学刻蚀法制备纳米电极的数学模型

介绍了液膜电化学刻蚀法制备纳米电极的原理及过程。根据钨棒刻蚀后的几何形状、电化学反应的基本原理及液体表面张力相关理论,建立了纳米电极制备的数学模型,为液膜电化学刻蚀法制备纳米电极奠定了理论基础。     

NR/SiO_2复合体系结合胶及动态力学性能研究

研究了白炭黑用量和Si69原位改性对NR/SiO2复合体系结合胶含量及其与动态力学性能之间关系的影响。结果表明,随着白炭黑用量的增大,2种复合体系(NR/SiO2/Si69和NR/SiO2)结合胶含量均呈现先增大后减小的趋势。当白炭黑用量达到临界值时,复合体系结合胶含量最大,此时Payne效应开始显现。当白炭黑用量超过临界值时,复合体系结合胶含量减小,形成完善的填料网络结构,出现明显的Payne效应。与NR/SiO2复合体系相比,NR/SiO2/Si69复合体系结合胶含量大大提高,白炭黑用量的临界值也相应提高,Payne效应减弱。     

One‐Step Synthesis of Superbright Water‐Soluble Silicon Nanoparticles with Photoluminescence Quantum Yield Exceeding 80%

Fluorescent silicon nanoparticles (SiNPs) have shown potential applications in bioimaging/biolabelling, sensing, and nanomedicine/cancer therapy due to their superior properties such as excellent photostability, low cytotoxicity, and versatile surface modification capability. Here, a simple, high‐yield, and one‐pot method is developed to prepare superbright, water‐soluble, and amine‐functionalized SiNPs with photoluminescence quantum yield (PLQY) comparable to fluorescent II–VI semiconductor quantum dots (QDs) but with much lower cytotoxicity. By introducing a commercially available amine‐containing silane molecule, N‐[3‐(trimethoxysilyl)propyl]ethylenediamine (DAMO), water‐soluble SiNPs are prepared with PLQY of 82.4% via a microwave‐assisted method. To the best of our knowledge, this is the highest PLQY value ever reported for water‐soluble fluorescent SiNPs. The silicon element in our SiNPs is mainly four‐valent silicon and thus these SiNPs may also be termed as oxidized silicon nanospheres or silica nanodots. We have also demonstrated the importance of the silane structure (e.g., a suitable amine content) on the photoluminescence property of the prepared SiNPs. As revealed by the time‐resolved photoluminescence technique, the highest PLQY value of DAMO SiNPs is correlated with their monoexponential decay with a relatively long fluorescence lifetime. In addition, the potential use of these SiNPs has also been demonstrated for fluorescent patterning/printing and ion sensing (including Cu²⁺ and Hg²⁺).     

表面改性SiO2纳米微粒的表征及摩擦学性能

文中采用透射电镜、X射线粉末衍射仪、FT-IR光谱仪对改性SiO2纳米微粒进行了结构表征,并考察了其在油性介质中的分散性及在往复摩擦试验机和四球摩擦试验机上的摩擦学行为.结果表明,此二氧化硅纳米微粒粒径为10～20nm,表面键合有机碳链化合物,在润滑基础油中有很好的分散性,作为润滑油添加剂具有显著的抗磨减摩性.     

纳米陶瓷微米高温合金复合涂层组织与性能

采用溶胶-凝胶化学包覆法制备纳米陶瓷微米高温合金复合粉末,用HVOF喷涂技术制备了复合涂层,采用SEM观察和摩擦磨损实验分析了复合粉末和复合涂层的组织和性能.研究表明:复合粉末是以纳米陶瓷为外壳包覆微米级高温合金颗粒核心的核壳式结构;陶瓷壳在喷涂过程中形成液相与高温合金液相熔合,烧结成致密陶瓷相,部分陶瓷在冷却过程中析出结晶体;复合涂层与基体的结合强度为59.2 MPa,摩擦系数为0.766,磨损率比纯高温合金涂层降低了32%.