亚相金属离子与两亲配体LB膜相互作用的研究

The complex formation of 2-hexadecylcarbamoyl-8-hydroxyquinoline(HHQ) monolayers at the air/water interface by reaction with metal ions from the subphase was investigated using X-ray photoelectron spectroscopy. The formation of HHQ-metal complexes leads to the appearance of new peaks assigned to the metal ions. The information on stoichimoetry provided by XPS indicated that a metal ion is coordinated by two HHQ molecules for La3+ and Cd2+ ions, but by one HHQ molecule for Mn2+ and Ni2+ ions.     

Alginate-magnesium aluminum silicate films for buccal delivery of nicotine

Sodium alginate-magnesium aluminum silicate (SA-MAS) dispersions with nicotine (NCT) were prepared at different pHs and characterized for the particle size and zeta potential, NCT adsorbed by MAS, and flow behavior before film casting. The physicochemical properties, NCT content, in vitro bioadhesive property, and NCT release and permeation of the NCT-loaded SA-MAS films were investigated. This study showed that incorporation of NCT into the SA-MAS dispersions caused a change in particle size and flow behavior and that NCT could be adsorbed by MAS. The formation of protonated NCT at acidic and neutral pHs could interact with negatively charged MAS via an electrostatic force, resulting in the formation of NCT-MAS flocculates/complexes that could act as microreservoirs in the films. The NCT-loaded SA-MAS films prepared at pH 5 yielded the highest NCT content due to non-significant loss of NCT during drying. Moreover, pH of the preparation also affected the crystallinity and thermal properties of the films. The NCT release and permeation across the mucosal membrane of the films could be described using a matrix diffusion controlled mechanism. In addition, the NCT-loaded SA-MAS films also possessed a bioadhesive property for adhesion to the mucosal membrane. This finding suggests that the NCT-loaded SA-MAS films composed of numerous NCT-MAS complexes as microreservoirs demonstrated a strong potential for use as a buccal delivery system.     

CCD紫外增强薄膜旋涂法工艺优化

在硅基探测器的入射窗上制备荧光下转换薄膜,是一种有效降低成本的紫外荧光增强技术。从理论上探讨了由聚二甲基硅氧烷与颜料黄101混合胶体的紫外荧光薄膜旋涂工艺参数与性能之间关系,搭建紫外荧光薄膜应用于光谱分析的性能测试实验平台,对紫外荧光增强薄膜旋涂工艺参数质量配比、旋涂转速进行优化。光谱分析探测器有两个主要指标,光谱响应灵敏度和光谱分辨率,分析与实验结果表明,利用旋涂法制备紫外增强荧光薄膜,旋涂转速将直接影响薄膜的厚度、表面粗糙度和荧光物质的分布,从而影响光谱分析系统的分辨率;紫外荧光增强薄膜的增强效率与荧光溶剂聚二甲基硅氧烷与荧光物质颜料黄101的质量比密切相关,质量比低无法满足对紫外响应效率的提高,但高质量比,荧光物质处在聚集态荧光自猝灭严重,也不利于增强薄膜的紫外响应效率。最终,在薄膜旋涂工艺优化的基础上,旋涂转速2 500～3 000 r·min-1,荧光物质与荧光溶剂质量比为7∶100制备出紫外荧光增强薄膜。汞灯特征光谱测试结果表明该薄膜313 nm紫外波长处探测响应灵敏度提高了1.6倍左右,对比分析镀膜前后特征光谱的半波带宽,镀制紫外增强荧光薄膜对其影响很小。     

The impact of chemical composition on the degradation kinetics of poly(lactic-co-glycolic) acid copolymers cast films in phosphate buffer solution

We have investigated the in vitro degradation of poly(lactic-co-glycolic) acid copolymer with different lactic to glycolic ratio: 50:50, 65:35, 75:25, 95:05 and 100:00 (mol. %). The degradation studies were performed on solvent cast films of controlled thickness and shape. The samples were incubated at 37 °C in phosphate buffered saline solution. The degradation was followed using potentiometry, light microscopy, gravimetry, size exclusion chromatography and differential scanning calorimetry. The same degradation process, as discussed in detail in our previous article for PLGA 50:50 (E. Vey et al., J. of Polym. Deg. and Stab. 2008, 93, 1896-1876), was observed for all the samples investigated, however the time scale over which the different events/degradation steps were observed increased with increasing lactic content of the polymer. The glass transition temperatures of the films increase with lactic content and are thought to have a significant impact on the rate of diffusion of water into the films - the higher the glass transition the slower the diffusion of water - and therefore on the degradation dynamics of the films. Kinetic parameters were extracted from the acid release, molecular weight and mass loss data. In each case linear correlations between the rate constants extracted and the lactic content of the polymer were found. The overall degradation rate of the films was found to decrease with increasing lactic content.     

间苯二酚-甲醛凝胶自发成膜技术研究

 以间苯二酚和甲醛为原料,对水相溶胶-凝胶聚合自发成膜技术获得间苯二酚-甲醛(RF)凝胶薄膜进行了研究。主要研究了溶胶-凝胶过程中冰醋酸（HAC）含量和反应温度对凝胶过程的影响,分析了RF有机凝胶自发成膜的形成机理。IR和SEM分析表明,所得到的凝胶膜具有典型的RF有机气凝胶结构,薄膜厚度大约为50 μm,膜由直径10 μm左右的粒子组成,没有观察到明显的孔洞结构。分析认为,在间苯二酚和甲醛占总溶液的质量分数为67％左右及控制pH值在一定的酸性范围,RF凝胶自发成膜过程和机理可以用RF凝胶的收缩机理加以解释,RF自发膜的表面形貌及形成机理与均匀泡沫的连续相分离机理类似。     

Thickness induced magnetic anisotropic properties of Tb-Fe-Co thin films

The influence of Tb₂₅Fe₆₁Co₁₄ thin film thicknesses varying from 2 to 300 nm on the structural and magnetic properties has been systematically investigated by using of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, magnetization, and magneto-optic Kerr effect microscopy measurements. Thin film growth mechanism is pursued and controlled by ex-situ X-ray refractometry measurements. X-ray diffraction studies reveal that the Tb₂₅Fe₆₁Co₁₄ films are amorphous regardless of thin films thicknesses. The magnetic properties are found to be strongly related to thickness and preferred orientation. With an increase in film thickness, the easy axis of magnetization is reversed from in-plane to out-of-plane direction. The change in the easy axes direction also affects the remanence, coercivity and magnetic anisotropy values. The cause for the magnetic anisotropy direction change from in-plane to out-of-plane can be related to the preferred orientation of the thin film which depends on the large out-of-plane coercivity and plays an important role in deciding the easy axes direction of the films. According to our results, up to the 100 nm in-plane direction is dominated over the whole system under major Fe-Fe interaction region, after that point, the magnetic anisotropy direction change to the out-of-plane under major Tb-Fe/Tb-Co interaction region and preferred orientation dependent perpendicular magnetic anisotropic properties become more dominated with 2.7 kOe high coercive field values.     

Elucidating the aryl hydrocarbon receptor antagonism from a chemical-structural perspective

ABSTRACT

The aryl hydrocarbon receptor (AhR) plays an important role in several biological processes such as reproduction, immunity and homoeostasis. However, little is known on the chemical-structural and physicochemical features that influence the activity of AhR antagonistic modulators. In the present report, in vitro AhR antagonistic activity evaluations, based on a chemical-activated luciferase gene expression (AhR-CALUX) bioassay, and an extensive literature review were performed with the aim of constructing a structurally diverse database of contaminants and potentially toxic chemicals. Subsequently, QSAR models based on Linear Discriminant Analysis and Logistic Regression, as well as two toxicophoric hypotheses were proposed to model the AhR antagonistic activity of the built dataset. The QSAR models were rigorously validated yielding satisfactory performance for all classification parameters. Likewise, the toxicophoric hypotheses were validated using a diverse set of 350 decoys, demonstrating adequate robustness and predictive power. Chemical interpretations of both the QSAR and toxicophoric models suggested that hydrophobic constraints, the presence of aromatic rings and electron-acceptor moieties are critical for the AhR antagonism. Therefore, it is hoped that the deductions obtained in the present study will contribute to elucidate further on the structural and physicochemical factors influencing the AhR antagonistic activity of chemical compounds.     

Evaluation of new organosolv dissolving pulps. Part II: Structure and NMMO processability of the pulps

The supermolecular structure of dissolving pulps produced from hardwood by the organosolv processes Acetosolv, Formacell, and Milox was characterized by physical methods (TEM, WAXS, SAXS, NMR) and compared with conventional Sulfite and standard commercial dissolving pulps. The suitability of the pulps for the NMMO technology was tested by spinning fibres and blowing films, whose structural and mechanical properties have also been determined. With TEM it was shown that the TCF-bleached organosolv pulps have only the primary (Formacell), the primary and S1 (Milox), or mainly the S1 (Acetosolv) layers exposed to the surface, whereas Sulfite pulping exposes the S2 cell wall layer. Especially for Milox and Acetosolv Eucalyptus wood pulps, a reduced degree of crystallinity was found, both with WAXS and NMR. The SAXS results indicate a lower pore intersection length for the new pulps as compared to conventional pulps. Unbleached organosolv pulps show a lower crystallinity, very low pore intersection lengths, and an average crystallite shape different from their bleached counterparts. The dissolution behaviour in NMMO and the processability of the bleached organosolv pulps was satisfactory so far. Fibres and films could be produced with structural and mechanical properties comparable with conventional Sulfite and standard commercial dissolving pulp products. However, unbleached organosolv pulps did not meet the requirements of the NMMO process.     

四元胶乳互穿聚合物网络的组成对其性能的影响

用分步乳液聚合法合成了具有核壳结构的胶乳互穿聚合物网络ＬＩＰＮ（ＰＭＭＡ－ＰＳ）／（Ｐｎ－ＢＡ－ＰＡＡ）；讨论了ＬＩＰＮ组成对乳液与膜性能的影响，提出了四元ＬＩＰＮ核壳结构的基本轮廓，探讨了软硬单体最佳配比及丙烯酸单体用量。     

二氧化钛纳米微粒膜光电化学行为的研究

利用不同的制备方法制备出二氧化钛纳米微粒膜，对二氧化钛纳米微粒膜的光电化学材为和产生的机理进行了研究．结果表明；二氧化钛纳米微粒膜除了具有传统半导体的光电化学性质外，还具有不同于传统半导体的光电化学性质这主要是出膜的微粒性引起的，可综合传统半导体和胶粒半导体两种模型来加以解释。