Dai Gan-ce

Ultrasonic degradation of polysilane polymers

The degradation of four polysilanes in solution irradiated by ultrasonic waves has been studied by measurements of reduced viscosity and dynamic mechanical behavior. In all cases ultrasonic degradation occurs. The ultrasonic waves cause the average molecular weight to decrease and the molecular-weight distribution to become narrower in a relatively short period. The degree and rate of degradation are related to the intensity of the ultrasonic waves. In addition, the degree of degradation decreases with increasing polymer concentration and the rate increases with increasing initial molecular weight of the polysilane. After irradiation, the molecular weights of polysilanes tended to the same value from various initial values.

Synthesis of glycidyl methacrylate-based matrix and its application in affinity chromatography of urokinase

A number of glycidyl methacrylate (GMA) copolymers were synthesized with various pore-forming agents in different proportions using ethylene dimethacrylate (EDMA) as a crosslinking agent. One of greater pore diameter was chosen as the matrix for affinity chromatography. This was treated with ammonia liquor and reacted with succinic anhydride to extend the spacer arm. The p-aminobenzamidine was immobilized to the succinylated resin as the ligand in the presence of water-soluble carbodiimide. The resulting resin had a ligand density of 45.6 μmol g wt−1 resin and was used for purification of crude urokinase with a purity ranging from 125 to 221 IU mg−1. The optimal condition for the adsorption of urokinase was 0.05 M phosphate buffer (pH 7.5) containing 1.0 M NaCl. The optimal elution conditions were: First the contaminating proteins were eluted with Tween 80 solution, then urokinase was eluted with 0.2 M HAc (pH 2.6). The elution yield was 93.7% with a 46-fold purification.