[Sample pretreatment methods of pesticide residues in Panax notoginseng of Chinese traditional medicine].

Two sample pretreatment methods of pesticide residues in Panax notoginseng of Chinese traditional medicine were developed. For Method I, the residues were extracted from homogenized tissue with n-hexane-dichloromethane (6:4) by means of ultrasonication, the crude extract was purified by an Envi-carb/NH2 solid-phase extraction (SPE) column. For Method II, matrix solid-phase dispersion (MSPD) technique was used for extracting and cleaning up. The eluates were concentrated by rotary evaporation, and then were redissolved in dichloromethane prior to GC-MS determination. The determination was performed in selected ion monitoring (SIM) mode with the external calibration for quantitative analysis. Under the optimal conditions, the results indicated that the methods are easier and faster, the recoveries of method I for the spiked standards at concentration of 0.01, 0.5, and 2.0 mg x kg(-1) were 81.90%-102.10% with the relative standard deviations (RSDs) of 3.60%-7.10%. The recoveries of method II were 96.26%-104.20% with the RSDs of 3.52%-7.94%. The detection limits (S/N) for residues of pesticides were in the range of 0.48-1.34 ng x g(-1). The results indicated that these multiresidue analysis methods can meet the requirements for determination of residue pesticides and can be appropriate for trace analysis of residue pesticides in Panax notoginseng.

Irradiation-mediated carbon nanotubes' use in cancer therapy.

Anticancer drugs such as biological therapeutic proteins and peptides are used for treatment of a variety of tumors. However, their wider use has been hindered by their poor bioavailability and the uncontrollable sites of action in vivo. Cancer nano-therapeutics is rapidly progressing, which is being applied for solving some limitations of conventional drug delivery systems. To improve the bio-distribution of anticancer drugs, carbon nanotubes have been used as one of the most effective drug carriers. This review discusses the carbon nanotubes-mediated methods for the delivery of anticancer drugs, with emphasis on the radiation-induced drug-targeted releasing and selective photo-thermal cancer therapy.

Protein-based alignment in 3D-QSAR of FBPase inhibitors.

Three-dimensional quantitative structure-activity relationship (3D-QSAR) studies were performed on Frusectose-1, 6-bisphosphatase (FBPase) inhibitors, based on molecular docking obtained by using GOLD and comparative molecular field analysis (CoMFA). Three random splits into training and test sets had been performed and the high leave-one-out (LOO) cross-validated correlation coefficients q(2) of 0.781, 0.725 and 0.801, respectively, revealed that the models are useful tools for the prediction of test sets as well as newly designed structures against FBPase activity. The superimposed CoMFA models on the receptor site of FBPase are guiding the design of potential inhibitory structures directed against FBPase activity.

Rapid microwave synthesis of chitosan modified carbon nanotube composites.

Chitosan modified multi-walled carbon nanotube composites were synthesized under microwave irradiation. The resultant chitosan modified multi-walled carbon nanotube composites were purified by twice adjusting of pH value of the solution and centrifugating in succession. The surface functional groups of chitosan modified multi-walled carbon nanotube composites are confirmed by Fourier transform infrared spectroscopy and UV-vis spectroscopy. Transmission electron microscopic images further show the morphologic changes of the carbon nanotubes. Thermal gravimetric analysis shows that the chitosan content in the chitosan modified multi-walled carbon nanotube composites is much higher than conventional methods. The whole reaction procedure can be completed in 1 h under microwave irradiation.