Poly(glycidyl methacrylate)‐grafted hydrophobic charge‐induction agarose resins with 5‐aminobenzimidazole as a functional ligand

Hydrophobic charge‐induction chromatography is a new technology for antibody purification. To improve antibody adsorption capacity of hydrophobic charge‐induction resins, new poly(glycidyl methacrylate)‐grafted hydrophobic charge‐induction resins with 5‐aminobenzimidazole as a functional ligand were prepared. Adsorption isotherms, kinetics, and dynamic binding behaviors of the poly(glycidyl methacrylate)‐grafted resins prepared were investigated using human immunoglobulin G as a model protein, and the effects of ligand density were discussed. At the moderate ligand density of 330 μmol/g, the saturated adsorption capacity and equilibrium constant reached the maximum of 140 mg/g and 25 mL/mg, respectively, which were both much higher than that of non‐grafted resin with same ligand. In addition, effective pore diffusivity and dynamic binding capacity of human immunoglobulin G onto the poly(glycidyl methacrylate)‐grafted resins also reached the maximum at the moderate ligand density of 330 μmol/g. Dynamic binding capacity at 10% breakthrough was as high as 76.3 mg/g when the linear velocity was 300 cm/h. The results indicated that the suitable polymer grafting combined with the control of ligand density would be a powerful tool to improve protein adsorption of resins, and new poly(glycidyl methacrylate)‐grafted hydrophobic charge‐induction resins have a promising potential for antibody purification applications.     

The catalytic oxidation of H2S in a stainless steel membrane reactor with separate feed of reactants

The oxidation of H₂S is studied in a membrane reactor with separate feed of reactants. As a novelty in the concept of separate introduction of the reactants, a sintered stainless steel membrane is used, because this type of material is easy to integrate into the reactor, and the catalytic properties of the membrane itself makes the often difficult activation superfluous. The macropore membrane (d_p>1 μm) is characterized in the absence of a pressure difference by diffusion and conversion experiments for determining the porosity to tortuosity ratio. Because the relative large pore diameter of the membrane, Knudsen diffusion is of minor importance and the last important structure parameter of the membrane, B₀, is determined in a permeation experiment.This membrane reactor is also studied in the presence of a pressure difference over the membrane; a situation where both diffusion and convection affect the overall mass transfer. For this reason, a model based on the dusty gas model (DGM) is used, where the structure parameters are estimated from isobaric conversion and permeation measurements and the physical constants are taken from literature. This model predicts the conversion in the presence of a pressure difference very well, without using fit parameters. Generally, it can be concluded that the performance of this sintered metal membrane reactor can be described and operated equally compared to ceramic membrane reactors with separate feed of reactants. Regarding the fact that there are several other types of sintered metals (e.g. nickel, silver or platinum), this type of membrane reactor seems to be applicable for several other chemical applications.     

Enantioselective trimethylsilylcyanation of aromatic aldehydes catalyzed by titanium alkoxide–chiral o-hydroxyarylphosphine oxides complexes

A series of new chiral titanium alkoxide–o-hydroxyarylphosphine oxides complexes has been used as catalysts in the asymmetric trimethylsilylcyanation of aromatic aldehydes. The corresponding cyanohydrins have been obtained in high chemical yields with good to excellent enantiomeric excesses up to 98%. The influence of the structural features of the catalysts on the enantioselectivity has been investigated.     

无规聚甲基丙烯酸甲酯链的温度系数

本文在旋转异构态理论基础上,建立了双侧基高分子链温度系数的计算公式,由此得到聚甲基丙烯酸甲脂的温度系数从间同链、无规链到全同链呈线性关系,这与实验数值一致.     

Évaluation de l'influence de sources acoustiques secondaires sur la puissance acoustique rayonnée

The boundary element method and equivalent sources method are currently used in vibroacoustic. While designing the model, we have to know if it is necessary or not to model some geometric “details”. In order to determine the acoustic part of these “details” as vibrating sources, we propose to study a simplified model of two point sources in opposite phase. We determine, on the one hand, the conditions of distance between sources, and, on the other hand, the output ratio for which the secondary source can be neglected when calculating the acoustic power radiated.     

Analysis of compressive failure of layered materials by kink band broadening

Failure by steady state kink band broadening in uni-directional fibre composites or layered materials is analysed. An incremental scheme for calculation of kink band broadening stresses and lock-up conditions in the band for arbitrary material behaviour is presented. The method is illustrated by material data which are representative for polymer matrix composites for which experimental work exists.     

Unconventional trapping of ultracold neutrons

In unconventional storage experiments we filled ultracold neutrons (UCN) into a Fomblin-grease coated trap and then immediately removed the UCN from the storage volume by an absorber, until their residual density in the trap was measured to be negligible. When subsequently the absorber was withdrawn a significant number of UCN of higher energies emerged from the trap. Their appearance cannot be attributed to heating or cooling of residual UCN. Further experiments were performed to investigate the origin of these UCN which we call `late UCN'. We noticed that application of a magnetic field gradient at the trap wall as well as a replacement of Fomblin grease on the surface by Fomblin oil gave rise to small but measurable alterations of storage behavior. These phenomena are consistent with the hypothesis of temporary adhesion of a few UCN to a rough wall.     

Rotating square billiard

Classical rotating billiards has two regular limits with a mixture of order and chaos between. The rotating square has distinctive features and shows clearly the mechanism for chaos with rotation or curved trajectories.     

A new derivation of the Picard-Fuchs equations for effective N = 2 super Yang-Mills theories

A new method to obtain the Picard-Fuchs equations of effective, N = 2 supersymmetric gauge theories in 4 dimensions is developed. It includes both pure super Yang-Mills and supersymmetric gauge theories with massless matter hypermultiplets. It applies to all classical gauge groups, and directly produces a decoupled set of second-order, partial differential equations satisfied by the period integrals of the Seiberg-Witten differential along the 1-cycles of the algebraic curves describing the vacuum structure of the corresponding N = 2 theory.     

胶原-磺化羧甲基壳聚糖/硅橡胶皮肤再生材料的制备及其对小型猪烫伤创面全层皮肤缺损的修复研究

制备了一种胶原-磺化羧甲基壳聚糖/硅橡胶皮肤再生材料,并以小型猪为模型,考察了其对烫伤全层皮肤缺损的修复性能.首先合成了磺化羧甲基壳聚糖,并对其结构进行了表征.制备了胶原-磺化羧甲基壳聚糖多孔支架,采用扫描电子显微镜(SEM)研究了磺化羧甲基壳聚糖含量对支架微结构的影响.随着磺化羧甲基壳聚糖含量的增大,胶原-磺化羧甲基壳聚糖支架从纤维结构向片状结构转化,且支架的孔径相对变大.采用体外成纤维细胞培养实验证明胶原-磺化羧甲基壳聚糖支架无明显细胞毒性.进一步将胶原-磺化羧甲基壳聚糖支架与硅橡胶膜复合,构建具有双层结构的皮肤再生材料.以小型猪为模型,评价了其对深度烫伤创面的修复性能.大体观察和组织学分析结果显示,胶原-磺化羧甲基壳聚糖/硅橡胶皮肤再生材料具有更快的血管化性能,且经该材料处理的创面能有效支持薄自体皮片的移植成活,实现深度烫伤创面的全层修复.