Dudu Wu

Lycorine-nanoparticles (LYC-NPs) were successfully synthesized using anti-solvent precipitation-freeze drying method, and characterized using transmission electron microscopy (TEM), particle size analysis and Fourier transform infrared spectroscopy (FTIR). Then, the antitumor effects of LYC-NPs against HepG2 cells were investigated, and the underlying molecular mechanisms were explored. Our results showed that LYC-NPs displayed potent antiproliferative against HepG2 cells concentration dependently. Flow cytometry analysis exhibited that LYC-NPs triggered apoptosis and impeded cell cycle in G0/G1 phase. Moreover, the up-regulated expression of cleaved caspases-3 and Bax, and decrease of mitochondrial membrane potential and the Bcl-2 expression were involved in LYC-NPs apoptosis, implying that LYC-NPs induced apoptosis via the mitochondrial-mediated apoptosis pathway. Furthermore, LYC-NPs distinctly impaired HepG2 cells migration and invasion with down-regulation of matrix metalloproteinase-2 (MMP-2) and MMP-9 expression. These results indicated that LYC-NPs could be an favorable agent for restraining the growth and metastasis of HepG2 cells.

A luminescent zinc (II)-based coordination poly-mer, [Zn(CPDA)(NO3)2)] (CPDA=1,2-cyclopentanedicarboxylic acid) (1), had been successfully synthesized in this study by the hydrothermal method. Afterwards, 1 was characterized through single crystal and power X-ray diffraction (PXRD), elemental analysis (EA), thermogravimetric analysis (TGA) and infrared spectrum techniques, respectively. Particularly, the stable sus-pension of 1 in aqueous solution had exhibited highly selective quenching towards Ni2+ in physiological buffer solution. Besides, the optimum fluorescence intensity could be found at the pH of 7.0 and the temperature of 25°C. Under these optimum condi-tions, the detection limit of Ni2+ ions could reach 5.23 × 10-7 mol·L-1. On the other hand, the effect of foreign ions on the flu-orescence intensity of 1 showed low interference response to the detection of Ni2+ ions. Additionally, the quenching was recog-nized as a static quenching procedure, which was proved by the quenching rate constant Kq (5.74 × 1013 L·mol-1·s-1).

The synthesis of methyl acetoacetate (MAA) by methoxycarbonylation of acetone with dimethyl carbonate (DMC) was carried out in the presence of MgO and alkali-promoted MgO catalysts. From among Li, Na, K, and Cs, potassium was found to be the most effective promoter to improve the activity of MgO. The effect of K/MgO with variable content of K was also investigated, and the individual catalysts were characterised by the XRD, BET, SEM, CO₂-TPD, and in situ CO₂ IR techniques. The results showed that the addition of a small amount of K (1.97 mass %) could promote MAA formation, but a higher K loading caused a decrease in the yield of MAA, which might result from particle agglomeration and the presence of stable potassium carbonates. In situ FTIR experiments of co-adsorbed reactants indicated that the reaction probably proceeded via abstraction of H_α from acetone by base sites.