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71.
72.
Biopolymers Produced by Cross-linking Soybean 11S Globulin with Whey Proteins using Transglutaminase 总被引:8,自引:0,他引:8
Heterogeneity of biopolymers was determined by cross-linking acetylated-11S acidic subunits (Ac-11S) of soy protein with α-lactalbumin and β-lactoglobulin. The extent of polymerization was determined by electrophoresis and HPLC. Differential scanning calorimetry (DSC) was used to determine thermal properties of starting proteins and biopolymers. HPLC data demonstrated the absence of biopolymers from Ac-11S, acetylated α-lactalbumin and acetylated β-lactoglobulin when each was incubated separately with transglutaminase (TG). However, Ac-11S formed biopolymers with α-lactalbumin and β-lactoglobulin when TG was added. TG catalyzed the formation of heterologous and homologous biopolymers from whey protein isolate (WPI) and soybean 11S globulin (11S). Cross-linking WPI and 11S provided biopolymers with improved heat stability which may be useful to provide functionality to food products. 相似文献
73.
Effect of vitamin C and its derivatives on collagen synthesis and cross-linking by normal human fibroblasts 总被引:1,自引:0,他引:1
Vitamin C (VitC) plays a critical role in the maintenance of a normal mature collagen network in humans (anti-scurvy properties) by preventing the auto-inactivation of lysyl and prolyl hyroxylase, two key enzymes in collagen biosynthesis. In this study two in vitro models were designed to evaluate the effects of VitC on collagen biosynthesis and cross-linking at cellular and tissue levels. It was shown that VitC induced a dose-dependent increase in collagen type I deposits by normal human fibroblasts (NHF) cultured in monolayer, and enhanced extracellular matrix contraction by NHF in a lattice model, in a non-cytotoxic range of concentrations (103m, 104m, 105m). Exogenous VitC supply could thus contribute to the maintenance of optimal collagenic density in the dermis and locally strengthen the collagen network. Vitamin C-phosphate (VitC-P) and vitamin C-glucoside (VitC-Glu) (two VitC derivatives presenting higher chemical stability in aqueous solution) were also tested in our two models, and showed similar biological properties, but with different potencies. These two compounds can be considered as pro-vitamins for skin, and could thus advantageously substitute for VitC in VitC-based anti-ageing products, as they allow the development of stable, easy-to-use formulations. 相似文献
74.
介绍了建筑行业对无卤低烟电缆需求的必然性及无卤低烟电缆主要的标准要求,分析了低压无卤低烟电缆的常规结构和绝缘层辅助阻燃的优势,为高端建筑电气专业设计人员选用高温交联无卤低烟阻燃聚烯烃绝缘电缆提供参考。 相似文献
75.
76.
In this study, segmented polyurethane/clay nanocomposites were prepared via in situ intercalative polymerization of polyether polyol mixed nanoclay with toluene diisocyanate, followed by chain extending with 1,4-butanediol. The reactive prepolymer tended to gel by increasing the clay content from 0.4 to 1.5 wt.%. This unusual phenomenon was found to be caused by a catalytic effect of quaternary ammonium intercalant on the organoclay. The procedure used for intercalated nanocomposites, is confirmed by wide angle X-ray diffraction studies. Thermogravimetric analysis results demonstrated a very good increase in onset degradation temperature by adding only 0.8 wt.% of organoclay. 相似文献
77.
阐述了高压交联聚乙烯(XLPE)绝缘收缩的原因,以悬链式生产线为例列举降低220 kV XLPE绝缘收缩的相应技术措施,通过实际工艺验证220 kV XLPE绝缘收缩率能够达到不大于4%的指标。 相似文献
78.
Lithium-ion polymer cells composed of a carbon anode and a LiCoO2 cathode are assembled with a gel polymer electrolyte cured by in-situ chemical cross-linking with novel cross-linking agents. The strong interfacial adhesion between the electrodes and the porous polyethylene membrane by the chemical cross-linking results in the stable capacity retention of the cell. However, a reduction in the ionic mobility in both the electrolyte and the electrodes adversely affects the high rate performance of the cell. These results imply that proper control of the cross-linking density in the cell is imperative for achieving good capacity retention and high rate performance of the cell. 相似文献
79.
The network inhomogeneity and the cooperative motion of the network chains of random cross-linked poly(styrene-co-maleic anhydride) gels were investigated by dynamic light scattering. Measurements were performed for gels in the preparation state as well as in the swelling equilibrium. Network inhomogeneities and cooperative motion were analyzed at varying the cross-linker concentration and the polymer volume fraction. While the cross-linker concentration has only a minor influence on the inhomogeneity and the diffusion constant Dcoop, the polymer volume fraction clearly influences both measured properties. The concentration dependence of Dcoop can be well described by a power law, as known for semi-dilute polymer solutions. In the preparation state the networks appear homogeneous, exhibiting dynamic contributions to the scattering intensity of 70-90%. Swollen to equilibrium stage, significant heterogeneities emerge, reducing the dynamic contributions to 10-20%. 相似文献
80.
综述了国内外高熔体强度聚丙烯的研究进展和应用前景,并简述了高熔体强度聚丙烯在挤出涂布和发泡等方面的应用。 相似文献