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Beijing, China

Yao R.,Beihang University | Li X.,Beihang University | Yao P.,Beihua University | Jiang L.,Major Laboratory | And 4 more authors.
ICIMA 2010 - 2010 2nd International Conference on Industrial Mechatronics and Automation | Year: 2010

As extremely important techniques of MRCAS, Z-string-beads phantom and optimization algorithm for manual imaging coordinates are investigated to improve the precisions of 3-D ultrasound (US) calibration which defines the spatial relationship between the US image plane and an external tracking device attached to the US probe. The phantom consists of accurate position beads and two layers of Z-string planar arrays. The beads can rapidly guide the user to align the probe accurately for imaging, so their coordinates are directly used in the algorithm for homologous points matching without any transformations; the optimized algorithm incorporates the imaging points coordinates (mass centre coordinates of each point) in multiple US images that corrects the manual marking coordinates of the imaging points. The calibration parameters are calculated by matching of homologous points in the image and the tracking device and the 2-D US image can be converted into 3-D US coordinates. The results show that this method can simplify the calibration algorithm, reduce the influences of the US beam thickness on the precision and improve the calibration precision and reconstruction accuracy of the 3-D US system. The calibration experiments are demonstrated with a magnetic locator, but the method could be suitable for other tracking devices. © 2010 IEEE. Source

Liu Z.L.,China Agricultural University | Cao J.,Major Laboratory | Zhang H.M.,Major Laboratory | Lin L.L.,Major Laboratory | And 4 more authors.
Journal of Agricultural and Food Chemistry | Year: 2011

The screening for insecticidal principles from several Chinese medicinal herbs showed that the ethanol extract of Aconitum episcopale roots possessed significant feeding deterrence against the red flour beetle, Tribolium castaneum. From the ethanol extract, six feeding deterrents were isolated by bioassay-guided fractionation. The compounds were identified as chasmanine, crassicauline A, karacoline, sachaconitine, talatisamine, and yunaconitine from their spectroscopic data. Chasmanine, talatisamine, karacoline, and sachaconitine exhibited feeding deterrent activity against T. castaneum adults, with EC50 values of 297.0, 342.8, 395.3, and 427.8 ppm, respectively. Yunaconitine and crassicauline A also possessed feeding deterrent activity against T. castaneum adults, with EC50 values of 653.4 and 1134.5 ppm, respectively. © 2011 American Chemical Society. Source

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