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DFT and TD-DFT study on structure and properties of organic dye sensitizer TA-St-CA
Cai-Rong Zhang,Zi-Jiang Liu,Yu-Hong Chen,Hong-Shan Chen,You-Zhi Wu,WangJun Feng,Dao-Bin Wang 한국물리학회 2010 Current Applied Physics Vol.10 No.1
The geometry, electronic structure, polarizability and hyperpolarizability of organic dye sensitizer TA-St-CA, which contains a π-conjugated oligo-phenylenevinylene unit with an electron donor.acceptor moiety, was studied using density functional theory (DFT), and the electronic absorption spectrum was investigated via time-dependent DFT (TD-DFT) with several hybrid functionals. The calculated geometry indicates that the strong conjugated effects are formed in the dye. The TD-DFT results show that the hybrid functional PBE1PBE and MPW1PW91 are more suitable than B3LYP for calculating electronic absorption spectra. The features of electronic absorption spectra were assigned on account of the qualitative agreement between the experiment and the calculations. The absorption bands in visible and near-UV region are related to photoinduced electron transfer processes, and the diphenylaniline group is major chromophore that contributed to the sensitization, and the interfacial electron transfer are electron injection processes from the excited dyes to the semiconductor conduction band. Compared with the similar dye D5, the good performance of TA-St-CA in dye-sensitized solar cells may be resulted from the higher energy level of the lowest unoccupied molecular orbital and the larger oscillator strengths for the most excited states with intramolecular electron transfer character.
윤택구,Shu Zheng,Soo-Yong Choi,Shan Rong Cai,이윤실,Xi Yong Liu,조경자,박건영 한국식품영양과학회 2010 Journal of medicinal food Vol.13 No.3
Previously, two case-control studies and a cohort study strongly suggested that Panax ginseng C.A. Meyer exerted non–organ-specific preventive effects against cancer. The purpose of the present study was to evaluate the effects of red ginseng extract on the incidence of human primary cancer. We conducted a randomized, double-blinded, placebo-controlled trial on 643 chronic atrophic gastritis patients in four hospitals in Zhejiang Province, China. Red ginseng extract powder (1g) was administered orally to each patient per week for 3 years and followed up for 8 years. The development of various cancers in the red ginseng subjects was compared to that of a placebo group. The red ginseng extract powder was specified in terms of its components. Twenty-four cancers of various organs were diagnosed from these subjects during the 11 years: eight lung cancers, six stomach cancers, two liver cancers, two colorectal cancers, and one cancer each of the nasopharynx, esophagus, pancreas, urinary bladder, prostate, and gallbladder. The red ginseng group, which included both genders, demonstrated a relative cancer risk of 0.54 (95% confidence interval, 0.23–1.28; P=.13) compared to the placebo group, which was not statistically significant. Among the 24 cancer patients, 21 were male. The male red ginseng group showed a relative cancer risk of 0.35 (95% confidence interval, 0.13–0.96; P=.03) compared to the male placebo group, which was highly significant statistically. In the present clinical trial on chronic atrophic gastritis patients, administration of red ginseng extract powder for 3 years exerted significant preventive effects on the incidence of non–organ-specific human cancers in males.