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Influence of laser intensity on the double-resonance multiphoton ionization process of NO molecule

Chinese Optics Letters 2008年第11期6卷 800-803页

作者：张贵银靳一东 College of Mathematics and Physics North China Electric Power University.Baoding 071003

The analytic formula of the ionization efficiency in the process of double resonance enhanced multi-photon ionization （DREMPI） is derived from the dynamic rate equation about the interaction of photon and material. Based on this formula, the ionization efficiency and the laser power index versus laser intensity in the DREMPI process of NO molecule, via A2E and S2E intermediate resonant states, is numerically simulated. It is shown that the ionization efficiency of NO molecule increases with the laser intensity until getting saturation, while the laser power index decreases with the enhancement of the laser intensity and changes to zero at last. The variation of the laser power index with the laser intensity indicates that the ionization efficiency reaches saturation in the one, two, and three excitation steps respectively. It is also found that the narrower the laser pulse duration is, the higher becomes the laser intensity for saturation.

关键词： ionization ionization of liquids Lasers Molecules Multiphoton processes Photoionization Photons Pulsed laser applications Pulsed laser deposition Resonance

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Use of Support Vector Regression Based on Mean Impact Value Model to Identify Active Compounds in a Combination of Curcuma longa *** Glycyrrhiza extracts

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Transactions of Tianjin University 2017年第3期23卷 237-244页

作者： Jianlan Jiang Qingjie Tan Weifeng Li Xinyun Du Ningzhi Liu Key Laboratory of Systems Bioengineering Ministry of EducationTianjin Key Laboratory of Biological and Pharmaceutical EngineeringSchool of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

A support vector regression based on the mean impact value (MIV) model was constructed to identify the bioactive compounds inhibiting proliferation of HeLa cells in a combination of turmeric (Curcuma longa L.) and liquorice (Glycyrrhiza) extracts. The quantitative chemical fingerprint from 50 batches of turmeric and liquorice extracts was established using high performance liquid chromatography hyphenated to an ultraviolet visible detector. Qualitative results were obtained using ultra performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry. A total of 46 peaks (peaks 1–15 from turmeric and 16–46 from liquorice) were selected as “common peaks” for analysis. The inhibitory effect of the combined extracts on HeLa cells was measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. It was found that 15 compounds (peaks: 8, 12, 30, 24, 46, 11, 14, 9, 3, 1, 44, 18, 7, 45 and 43) possessing high absolute MIV exhibited a significant correlation with the cytotoxicity against HeLa cells; most of these have already been confirmed with potential cytotoxicity in previous research. The important potential application of the present model can be extended to help discover active compounds from complex herbal medicine prior to traditional bioassay-guided separation. It is considered that this could be a useful tool for re-developing herbal medicine based on the use of these active compounds. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg.

关键词： Bioassay Electrospray ionization Food products High performance liquid chromatography ionization of liquids Liquid chromatography Mass spectrometry Medicine Plant extracts Regression analysis

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