Physical vapor deposited TiN coatings oxidized by solar beam heat treatment in air were examined by microprobe Raman spectroscopy. The Raman spectra of TiN treated at 400 °C indicated incipient oxidation by the presence of anatase TiO2 and additionally showed a broadband feature around the forbidden TiN vibrational mode. Inhomogeneous mixtures of rutile TiC>2 and small amounts of anatase polymorph (<10%) were detected for the treatments at 600 °C only during the initial stage of oxidation. Prolonged treatment at 600 °C resulted in a complete anatase-to-rutile conversion. Rutile was identified as the single product of oxidation of the TiN samples treated at 800 °C. Peak analysis of the rutile spectra revealed no substantial spectral shifts, demonstrating an oxide growth of nearly stoichiometric rutile with an estimated composition in the range of Ti02±o.o2-The Raman scattered light intensity could be correlated with the rutile layer thickness.

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An extract of the fruits of Trichosanthes tricuspidata collected in North Vietnam was found cytotoxic in KB cells. A bioassay-guided fractionation led to the isolation of a series of cucurbitacins of which two are new: tricuspidatin and 2-O-glucocucurbitacin J. Their isolation and structure determination are described.

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