β-环糊精与四环素类抗菌素酸性降解物包络物的荧光光谱研究与应用

对四环素类抗菌素在浓硫酸作用下的降解物脱水四环素类抗菌素与β－环糊精的相互作用进行了研究，发现脱水四环素，脱水土霉素能与β－环糊精形成包络物，而脱水金霉素和脱水强力霉素与β－环糊精的包络作用则十分微弱，从四环素类抗菌素和β－环糊精的分子结构出发，对包络物的形成机理进行了研究，分别测定了包络物的形成常数，建立了利用转化荧光结构法测定四环素、土霉素和甲烯土霉素这３种四环素类抗菌素的新方法，结果令人满意．

PREPARATION AND PROPERTIES OF POLY(LACTIC ACID-CO-GLYCOL TEREPHTHALIC ACID)COPOLYESTER

To obtain a kind of biodegradable polymer material with satisfactory properties, a new biodegradable copolyester poly（lactic acid-co-glycol terephthalate） （PETA）, was synthesized from three monomers of lactic acid, glycol and terephthalic acid. The resulting copolyesters, PETA, were characterized by FT-IR, ^1H-NMR, DSC, TGA and by the ways of weight loss rate to characterize their biodegradability. The findings in this work indicated that, the Tins and Tas of copolyesters PETA increased with increasing contents of the terephthalic acid units. From the biodegradation tests in natural soil, boiling water, acid buffer solution and alkali buffer solution, it was shown that the biodegradability of copolyesters PETA decreased with increasing contents of the terephthalic acid units.

In Vitro Antimicrobial Activity Study of Some New Arginine-based Biodegradable Poly （Ester Urethane）s and Poly （Ester Urea）s

Bactericidal activity of some arginine based biodegradable polymers-PEURs （poly （ester urethane）s） and PEUs （poly （ester urea）s） with low cytotoxicity was studied in in vitro experiments. Various bacterial strains both Gram-positive and Gram-negative were used to explore the bactericidal activity of the cationic polymers. As the test objects, the following microorganisms were used： Bacillus subtilis, Staphylococcus aureus, Mycobacterium album, Pseudomonas fluorescens, Escherichia coli, Actinomyces griseus and Aspergillus niger. The obtained results showed that the new cationic polymers suppressed the growth of the studied microorganisms and the bactericidal activity of the tested cationic polymers strongly depending on their chemical structure.

Anaerobic biodegradation of RDX and HMX with different co-substrates

Simulated wastewater of hexahydro-l,3,5-trinitro-l,3,5-triazine （RDX） and octahydro- 1,3,5,7-tetranitro- 1,3,5,7- tetrazocine （HMX） was treated under anaerobic conditions with co-substrates such as ammonium chloride, dex- trose, sodium acetic, sodium nitrate and sulfate. The results showed that with nitrogen compounds such as ammonium chloride added as co-substrate, no significant change was observed, indicating that the molar ratio of N/C for RDX and HMX is sufficient for biodegradation. With the addition of dextrose and acetate to the system, biodegradation efficiency was enhanced greatly. For example, with dextrose as the co-substrate, degradation efficiency of 99.1% and 98.5% was achieved for RDX and HMX, respectively, after treatment for 7 days. When so- dium acetic was used as the co-substrate, the enhancement of degradation percentage was similar, but was not as high as that with dextrose, indicating the selectivity of RDX and HMX to co-substrate during anaerobic degrada- tion. With sodium nitrate as the co-substrate, the degradation efficiency of RDX or HMX decreased with the increase of salt concentration. Sodium sulfate has no significant effect on the biodegradation of RDX and HMX. A well-selected co-substrate should be employed in applications for degradation of RDX and HMX wastewaters.

Environmentally Degradation of r-PMMA/PMMA-Blend-PU/Ecoflex Sheet

Poly （methyl methacrylate） scrap was applied to prepare the impact modification of r-PMMA/PMMA-blend-PU/Ecoflex sheet by casting process. The Ecoflex and polyurethane were used as biodegradable polymer and impact modified respectively. This research was ascertained tile way to reduce the processing cost of PMMA sheet and the industrial waste by recycled PMMA scrap into the production process. The r-PMMA/PMMA-blend-PU/Ecoflex sheet was studied potential degradation by landfills for six months. After degradation the percentage of weight loss of specimens was increasing depend on amount of Ecoflex content and degradation period. While, the surface morphology of r-PMMA/PMMA-blend-PU/Ecoflex sheet after six months was damaged and demonstrated that Ecoflex had an effect on PMMA-blend-PU sheet in potential biodegradation. The mechanical and physical properties of r-PMMA/PMMA-blend-PU/Ecoflex sheet were described. Finally, the impact strength of r-PMMA/PMMA-blend-PU/Ecoflex sheet from this research, it is possible to use r-PMMA and Ecoflex in the acrylic casting sheet product.

PbCrO_4 yellow-pigment nanorods: An efficient and stable visible-light-active photocatalyst for O_2 evolution and photodegradation

Here, PbCrO4 nanorods, a commonly used and low-cost yellow pigment, was synthesized via a simple pre-cipitation reaction and can serve as a highly efficient oxygen production and photodegradation photocatalyst. The obtained PbCrO4 nanorods exhibit excellent stability and pho-tocatalytic performance for O2 evolution from water. The production rate is approximately 314.0μmol h^-1 g^-1 under visible light, and the quantum efficiency is approximately 2.16% at 420±10 nm and 0.05% at 600±10 nm. In addition, the PhCrO4 shows good degradation performance for methylene blue, methyl blue, methyl orange and phenol under visible-light irradiation. These results indicate that it is potential to fabricate an effective, robust PbCrO4 photocatalyst by trans-forming heavy-metal pollutants Pb（II） and Cr（VI） into a highly efficient O2 evolution and photodegradation material. This strategy which uses pollutant to produce clean energy and degrade contaminants is completely green and environmentally benign, and thus could be a promising way for practical environmental applications. Keywords： 02 evolution, pollutant, PbCrO4 nanorods, visible-light-active, photocatalyst