Abstract: The objective of the study was to evaluate the effect of a novel biodegradable membrane on the prevention of postoperative adhesion formation. The membrane was prepared by blending 50% PLA (polylactic acid) with 50% PTMC (polytrimethylene carbonate). The prepared blends polymer membrane was more flexible than pure PLA membrane, as measured by glass-transition temperature and tensile study. Cytotoxicity study revealed that PLA/PTMC blends membrane showed good biocompatibility. The membrane elicited slight tissue reaction based on the results of histological study. Thirty adult Japanese rabbits were used for the intestine adhesion model. The treatment group had PLA/PTMC membrane, the control group had chitosan, and the blank control group was not operated. The animals were housed for two weeks and sacrificed to investigate adhesion of intestine. Compared with the blank control group, the treatment group and the control group lowered the extent of adhesions (p < 0.01), but the treatment group was better than the control group (p < 0.05). The in-vivo studies confirmed that PLA/PTMC blends membrane could prevent postoperative adhesions.

The process, thermodynamical isotherm and mechanism of Cr(III) uptake by Spirulina platensis were investigated in this paper. At the beginning of Cr uptake, Cr is physically adsorbed to the surface of algal cell by electrostatic attraction. Finally, chemical complexation through ion-exchange with K+, Mn2+, Ca2+, Mg2+, Na+, Fe3+, Zn2+, H+, etc. ions by reversible or irreversible strategies plays the main role in Cr uptake. Most of the absorbed Cr are steadily bound to proteins, polysaccharides, lipids, etc. Biological ligands, whereas only a very small part of Cr are loosely adsorbed on the algal surface. Langmuir isotherm model seems to be suitable for describing Cr uptake than Freundlich isotherm model. pH is the most important factor influencing Cr uptake as well as anions, cell concentration, Cr concentration, temperature, light. Scatchard analysis and isotherm analysis indicate multi types binding sites for Cr and multi interactions between Cr and alga. Bioaccumulation strategy is suggested to be involved in Cr uptake besides biosorption e.g. adsorption and chemical complexation. S. platensis is of efficiently capable in the uptake of Cr(III), consequently high-value Spirulina can be produced.

The influence of different denaturants on the phosphorescence spectrum and lifetime decay of Escherichia coli alkaline phosphatase (AP) was investigated. Phosphorescence intensity and lifetime of tryptophan residue (Trp-109) decrease upon addition of guanidine hydrochloride, ethylene diamine tetraacetic acid, and urea or decreasing acidity. The experiments show that AP undergoes different pathways with different denaturants and that the activation energy data, DS8" and DH8" further confirm that there is a stable intermediate state between the folded and unfolded AP states in solution.

Dextran is a bacterial polysaccharide which can be produced from sucrose and usually used for clinical treatment as one kind of practical polysaceharide drags. The molecular weight distribution of dextran is an important index for its application. However, it is hardly to control strictly by the traditional separating method with ethanol. Taking separation and purification of medicinal dextran as the object of this study, a new separation technology, coupling electro-ultra-filtration with solvadng-out-crystagization (EUF-SOC) was developed and applied successfully, It was found that the permeate flux of optimized EUF-SOC technology is several times of normal ultra-filtration (UF) or enhanced ultrafiltration with an electric field (EUF), and its quality is higher than that of traditional process. The selective crystallization of dextran can be realized and homogeneous dextran crystals can be got in the process of membrane filtration by using EUF-SOC technology. The results showed that the mass transfer coefficient (k) of EUF-SOC process is about 4 times of UF and 2 times of EUF.

the problems of prod. e quality, especilly the colour of white sagar. ace prominent in sugar factories in China because of the present low dliciency of clarification and decolorization in the sulphitation process. Similar problems also occur in factories with car bonatation. The colour of white sugar may be either from inlusions inside the rytals or n the sugar surface. Thus it is necessary to remove the impurities both in the inclusions and on the surface as much as possible. As a preventive measure, it is desirable to reduee colour in the juice and raw syrup. To improve charification. a new clarificant, G409, has been developed. It can be used both in mixed juice clacitication and in syrup flotation creacmcnt after elther suiphltation or caronatation. The improved syrup flotation with G409 and H3PO4 has been applied in a number of factories using sulphitation and carbonatation in Guangdong and Fujia Provinces. The results indicate that the quality of white sugar can be improved effectively and economically.