A rapid and sensitive gas chromatography with mass spectrometry method for the determination of venlafaxine in rat plasma has been developed and applied to a drug-drug interaction study of fluoxetine on pharmacokinetics of venlafaxine in rats. Rat plasma was spiked with 2% aqueous ammonia before subjected to preactivated C solid-phase extraction columns and eluted with methanol. No endogenous interferences were observed under optimal condition. The calibration curve was linear (R = 0.9994) in the range of 10-1000 ng/mL. The quantification limit of venlafaxine in rat plasma was 10 ng/mL. The accuracy was in the range of 85-110%, and the extraction recovery was no less than 50%. Both the intra- and interday precision were 5.0-10.7%. The concentration-time curve showed that plasma concentrations of the coadministration group (group B) were higher than that of single dose group (group A). Both values of C (0.069 mg/L) and AUC (0.291 mg h/L) in group B were statistically greater than that of C (0.046 mg/L) and AUC (0.181 mg·h/L) in group A (P < 0.05). The results indicated that a significant effect of fluoxetine was shown on the pharmacokinetics of venlafaxine, suggesting that drug-drug interactions are of concern for the treatment of depression with the combined use of venlafaxine and fluoxetine.

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Gearbox was a key component of wind turbine but with the highest failure rate, so it was necessary to analyze its safety and reliability. In this paper, gears in MW wind turbine gearbox were analyzed by nonlinear finite element contact analysis method. The changing regularity of the stress was found as tooth mesh, and it was proved to be reliable by comparing with the result of theoretical calculations. The maximum contact stress existed on the second engaged tooth as well as the vicinity of the pitch circle of gears. The stress concentration phenomena occurred at the tooth root fillet which caused the main failure form of gears.

In order to find out its active behavior, the extractives of wheat straw biomass were adsorbed and determined by Py-GC-MS. And the main constituents were eicosane, stigmasterol, 22,23-dihydro-, .gamma.-sitosterol, stigmasterol, campesterol, nonacosane, stigmast-4-en-3-one, lup-20(29)-en-3-one, 13-tetradecen-1-ol acetate, 1,3-butadiene, 2- methyl-, 9-octadecenoic acid, (e)-, acetic acid, stigmast-5-en-3-ol, oleate, 1-nonadecene, heptacosane, 4,22-stigmastadiene-3-one, 4-((1e)-3-hydroxy-1-propenyl)-2- methoxyphenol, 1-heptene, 2-isohexyl-6-methyl-, etc.