Photolysis of nonylphenol ethoxylates: the determination of the degradation kinetics and the intermediate products.

The photolysis of nonylphenol ethoxylates with an average oligomers length of ten ethoxylate units (NPEO(10)) in aqueous solution under UV, as well as the influence of humic acid (HA) on the photolysis was studied. A 125W high-pressure mercury lamp was employed as the light source. The intermediate products from the photolysis were determined by LC-MS. The results indicated that NPEO(10) underwent direct photolysis upon exposed to UV. The degradation pathway was complex. Besides the generally proposed degradation pathway of ethylene oxide (EO) side chains shortening, the oxidation of alkyl chain and EO chain led to intermediates having both a carboxylated (as well as carbonylated) ethoxylate and alkyl chain of varying lengths. The hydrogenation of benzene ring was also detected. The kinetics data showed that the first order reaction kinetics could be well used to describe the kinetics of NPEO(10) degradation. In the presence of dissolved organic matter by HA addition, the performance of NPEO(10) photodegradation was reduced. The photolysis rate decreased with increased HA concentration.

Investigation of imprinting parameters and their recognition nature for quinine-molecularly imprinted polymers.

A series of molecularly imprinted polymers (MIPs) was prepared using quinine as the template molecules by bulk polymerization. The presence of monomer-template solution complexes in non-covalent MIPs systems has been verified by both fluorescence and UV-vis spectrometric detection. The influence of different synthetic conditions (porogen, functional monomer, cross-linkers, initiation methods, monomer-template ratio, etc.) on recognition properties of the polymers was investigated. Scatchard analysis revealed that two classes of binding sites were formed in the imprinted polymer. The corresponding dissociation constants were estimated to be 45.00 micromol l(-1) and 1.42 mmol l(-1), respectively, by utilizing a multi-site recognition model. The binding characteristics of the imprinted polymers were explored in various solvents using equilibrium binding experiments. In the organic media, results suggested that polar interactions (hydrogen bonding, ionic interactions, etc.) between acidic monomer/polymer and template molecules were mainly responsible for the recognition, whereas in aqueous media, hydrophobic interactions had a remarkable non-specific contribution to the overall binding. The specificity of MIP was evaluated by rebinding the other structurally similar compounds. The results indicated that the imprinted polymers exhibited an excellent stereo-selectivity toward quinine.

[Monomers optimization and properties evaluation of quercetin-imprinted polymer and its application to thin layer chromatography stationary phase].

The quercetin-molecularly imprinted polymers with specific affinity and selectivity were prepared by using methacrylic acid (MAA), acrylamide (AM), N,N-(diethylamino) ethyl methacrylate and 2-vinylpyridine as functional monomers, respectively. The adsorption properties for template were studied by equilibrium binding experiments. The results showed 2-VP and DEAEM based on ionic interaction with quercetin possessed better imprinting effects. Using the quercetin-imprinted polymers as thin layer chromatographic stationary could successfully separate the template from the other structurally related compounds. In addition, the influence on adsorption effect about the particle size and repeating times of MIP were investigated.

[Studies on chemical components of Cirsium segestum].

Six chemical components were got from the alcohol extract of Cirsium segestum, their structures were identified by UV, IR, NMR, MS and EA. They were 5,7-dihydroxyflavone, baicalin, oleanolic acid, cholesterol, methyl ursolate and rutin. The first to the fifth of which were got from Cirsium segestum for the first time.

[Protective effect and mechanism of curcumin on ActD/TNF-α-induced synergistically apoptosis in PC12 cells].

AIM: To investigate the protective effect and mechanism of curcumin against ActD/TNF-α-induced synergistically apoptosis in PC12 cells. METHODS: MTT assay was used to evaluate the optimal concentration of drugs; Hoechst 33258 fluorescent staining to observe apoptosis of PC12 cells, JC-1 was used to detect the mitochondrial membrane potential (MMP), real-time PCR was used to detect the expression of two apoptotic genes: Bcl-1 and Bax. RESULTS: ActD/TNF-α can synergistically reduce viability of PC12 cells(P<0.05), increase the number of cells with pyknosis and karyorrhexis, increase apoptotic rate of cells (P<0.05), decrease MMP in cells, and downregulate expression of Bcl-2(P<0.05). After treating with curcumin(5 µmol/L), survival of PC12 cells was increased(P<0.05), the number of cells with pyknosis and karyorrhexis was reduced, MMP and expression of Bcl-2 were increased(P<0.05). CONCLUSION: Curcumin can resist the ActD/TNF-α-induced synergistically apoptosis in PC12 cells, the mechanisms of which may be related to an increase in MMP and Bcl-2 expression.