Effect of bases with different solubility on the release behavior of risperidone loaded PLGA microspheres

Poly (D, L-lactide-co-glycolide) (PLGA) microspheres are attractive delivery vehicles due to their excellent sustained release capabilities. One major problem with PLGA microspheres is that the hydrophobic properties of PLGA generally cause a lag period in the process of drug release, leading to fluctuation of drug concentration in the blood and various resulting adverse reactions. Herein, Mg(OH)?, an inorganic base, and arginine, an organic base, were separately co-encapsulated into risperidone-loaded PLGA microspheres at varying concentration using the solvent evaporation method to improve release profiles from the microspheres. High encapsulation efficiencies were obtained in all formulations. The surface of base-free microspheres was smooth, whereas a few pores formed in base co-encapsulated microspheres. After 7-days degradation, many inter-connecting pores were formed in the interior of the microspheres containing 10 mg Mg(OH)?. The final pH in the microspheres with Mg(OH)? was higher than in those with arginine after 28-days degradation. The initial release of risperidone from microspheres containing Mg(OH)? was higher than from those containing arginine, and the latter release exhibited a more uniform pattern. Microspheres with 5mg and 10mg arginine exhibited zero-order release kinetics. However, both bases eliminated the lag phase of release. These results indicate that the incorporation of bases has potential in addressing the problem of the lag period in drug release from PLGA microspheres, and improving release behavior toward an ideal model.     

A novel scalable synthesis process of PPTA by coupling n-pentane evaporation for polymerization heat removal

In this study,we compared the effect of n-pentane and ice-water bath on removing the thermal effect in the poly（p-phenylene terephthalamide）（PPTA） polymerization process.The results indicate that the n-pentane can help to transfer the reaction heat faster and better.Adding suitable amount of n-pentanes into the PPTA preparation process not only improve the heat transfer,but also reduce the motor power in the polymerization process.Moreover,the introduction of n-pentane properly does not result in decrease of the inherent viscosity(η_inh) of polymer.Instead,it leads to increased viscosity of polymer during the PPTA preparation process.The results indicate that n-pentane can effectively transfer the reaction heat and avoid overheating during the polymerization of PPTA.     

苋菜红与胭脂红荧光光谱的比较分析

测量了胭脂红以及其同份异构体苋菜红的荧光光谱.胭脂红标准溶液在220～400 nm不同波长激发光下,分别在420 nm,530 nm,635 nm,687 nm波长处产生了四个荧光峰,苋菜红在220～430 nm不同波长激发光下,在654 nm处产生了一个明显荧光峰.胭脂红产生四个荧光峰是由于其具有四种可以发射荧光的荧光团,为了研究这四种荧光在不同激发光激励下产生荧光的敏感程度,以及找到胭脂红和苋菜红这两种色素产生荧光的基团之间的联系.利用荧光强度的加和性原则,分别对这两种物质的荧光强度进行了理论计算.认为苋菜红的荧光峰对应丁胭脂红的第三个荧光峰,根据此特点,初步分析了四种荧光团对这两种色素在荧光发射过程中的影响程度,同时还从结构上分析了两种色素荧光光谱差异的根本原因.     

人血清中总胆固醇的光谱学研究

采用光谱学方法对总胆固醇含量不同的高胆固醇血症血清进行了研究.获得了正常人血清和高胆固醇血症血清的吸收光谱和荧光光谱(λex=407 nm), 并讨论了二者的谱线特征与差异.实验结果表明,高胆固醇血症血清的吸收光谱和荧光光谱不同于正常人血清的吸收光谱和荧光光谱,高胆固醇血症血清不仅是吸收率和荧光强度高于正常人血清的相应值,而且还有新的吸收峰和荧光峰出现.由此可见,通过比较待测血清的吸收光谱和荧光光谱可以初步判定血清中胆固醇的含量是否异常.这为血清中总胆固醇含量的检测提供了光谱学的实验数据.     

α粒子能损法精确测量膜厚

利用α射线与材料的相互作用设计测量薄膜厚度的方法.用SRIM软件模拟计算了α粒子在Au膜和核乳胶中的运动,对Au膜厚度、α粒子在核乳胶中的射程实验数据结果分别用Mathematica数值求解和SRIM软件计算.可根据径迹的长短、粗细鉴定粒子的种类和能量.     

New synthesis of high-quality storage phosphors

We present a single step synthesis method for the photostimulable X-ray storage phosphor BaFBr:Eu²⁺ which results in a highly sensitive powder with a relatively small average grain size of 5.4 μm. The starting chemical reagents are BaCO₃, NH₄F, NH₄Br and EuF₃. The reaction initiated by the decomposition of the ammonium materials leads to highly volatile hydrogen halide gases which react with the BaCO₃ to form BaFBr at temperatures up to 300 °C. Further heating results in the incorporation of Eu²⁺ and the formation of halide vacancies at temperatures in between 390 and 580 °C. The resulting photostimulated luminescence (PSL) efficiency is optimized after sintering at 800 °C. The reaction process is monitored by differential thermal analysis (DTA) and the reaction products are detected by mass-spectroscopy which confirms the proposed chemical reactions. Intermediate and final products are identified using X-ray diffraction. Photoluminescence (PL) and PSL spectra show the incorporation of Eu²⁺ into the lattice, as well as a PL peak at 470 nm which is not present in the PSL spectrum. This peak is shown to originate from O^2? in the lattice and directly affects the PSL sensitivity.     

A real‐time Mooney‐viscosity prediction model of the mixed rubber based on the Independent Component Regression‐Gaussian Process algorithm

With the rapid development of rubber industry, it becomes more and more important to improve the performance of the quality control system of rubber mixing process. Unfortunately, the large measurement time delay of Mooney viscosity, one of the most important quality parameters of mixed rubber, badly blocks the further development of the issue. The independent component regression‐Gaussian process (ICR‐GP) algorithm is used to solve such typical nonlinear “black‐box” regression problem for the first time to predict Mooney viscosity. In the ICR‐GP method, the non‐Gaussian information is extracted by the independent component regression method firstly, and then the residual Gaussian information is extracted by the Gaussian process method. Meanwhile, both the linear and nonlinear relationships between the input and output variables can be extracted through the ICR‐GP method. With the fact that there is no need to optimize parameters, the ICR‐GP method is especially suitable for “black‐box” regression problems. The highest prediction accuracy was achieved at M = 0.8765 (the root mean square error), which was high enough considering the measuring accuracy (M = ±0.5) of the Mooney viscometer. It is by using the online‐measured rheological parameters as the input variables that the measurement time delay of Mooney viscosity could be dramatically decreased from about 240 to 2 min. Consequently, such Mooney‐viscosity prediction model is very helpful for the development of the rubber mixing process, especially of the emerging one‐step rubber mixing technique. The practical applications performed on the rubber mixing process in a large‐scale tire factory strongly proved the outstanding regression performance of this ICR‐GP Mooney‐viscosity prediction model. Copyright © 2012 John Wiley & Sons, Ltd.     

Fast-Response Nickel-Promoted Indium Oxide Catalysts for Carbon Dioxide Hydrogenation from Intermittent Solar Hydrogen

Construction of a “net-zero-emission” system through CO₂ hydrogenation to methanol with solar energy is an eco-friendly way to mitigate the greenhouse effect. Traditional CO₂ hydrogenation demands centralized mass production for cost reduction with mass water electrolysis for hydrogen supply. To achieve continuous reaction with intermittent and fluctuating flow of H₂ on a small-scale for distributed application scenarios, modulating the catalyst interface environment and chemical adsorption capacity to adapt fluctuating reaction conditions is highly desired. This paper describes a distributed clean CO₂ utilization system in which the surface structure of catalysts is carefully regulated. The Ni catalyst with unsaturated electrons loaded on In₂O₃ can reduce the dissociation energy of H₂ to overcome the slow response of intermittent H₂ supply, exhibiting a faster response (12 min) than bare oxide catalysts (42 min). Moreover, the introduction of Ni enhances the sensitivity of the catalyst to hydrogen, yielding a Ni/In₂O₃ catalyst with a good performance at lower H₂ concentrations with a 15 times adaptability for wider hydrogen fluctuation range than In₂O₃, greatly reducing the negative impact of unstable H₂ supplies derived from renewable energies.     

Promoting Syngas to Olefins with Isolated Internal Silanols-Enriched Al-IDM-1 Aluminosilicate Nanosheets

Selective conversion of syngas to value-added olefins has attracted considerable research interest. Regulating product distribution remains challenging, such as achieving higher olefin selectivity, propylene/ethylene (P/E) and olefin/paraffin (O/P) ratios. A new pentasil zeolite Al-IDM-1 with recently approved − ION structure, composed of 17-membered-ring (MR) extra-large lobed pores and intersected 10-MR medium pores, shows a C_2–6⁼ selectivity up to 85 % and a high O/P value of 14 in the conversion of syngas when being combined with Zn_aAl_bO_x oxide. Moreover, for the high-silica Al-IDM-1 with Si/Al ratio of 400, the selectivity of propylene and butene accounts for 88 % in C_2–4⁼, resulting in high P/E (>4) and butene/ethylene (B/E >3) ratios. The high C_3–4⁼ selectivity is contributed by two main reasons, that is, the relatively weak acidity of Al-IDM-1 zeolite enhances the olefin-based cycle revealed by the probe reactions of methanol-to-propylene (MTP) and 1-hexene cracking, and the rich isolated internal SiOH groups in Al-IDM-1 promote the desorption of C_3–4⁼, once they are formed inside zeolite pores.