• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.245.1-245.1
• /
• 2002

It has been known that resveratrol, a phytoalexin present in grapes mainly, has antioxidant. anti-inflammatory, and cancer chemopreventive activity. One mechanism of its anti-inflammation and cancer prevention is considered to modulate cyclooxygense-2 (COX-2) activity. Since COX-2 plays an important role in inflammation and carcinogenesis, the potential COX-2 inhibitors have been considered as anti-inflammatory or cancer chemopreventive agents. (omitted)

• ALGAE
• /
• v.29 no.4
• /
• pp.289-297
• /
• 2014

The taxonomic status and the distribution of Rosenvingea species need attention because of the difficulties in morphological identification in the laboratory as well as in the field. We analyzed mitochondrial cox3 and plastid psaA gene sequences from Rosenvingea species from Vietnam, Mexico and Panama in combination with morphological examinations. Our results confirmed the occurrence of R. intricata and R. orientalis in Vietnam. R. intricata formed dense decumbent mats with many flat branches, often inter-adhesive, and was up to 5 cm in diameter. R. orientalis thalli were up to 18 cm long with narrow (less than 2 mm in width) tubular to compressed fronds. Both cox3 and psaA phylogenies revealed the non-monophyly of the genus Rosenvingea, as reported previously for other scytosiphonacean genera.

• Bulletin of the Korean Chemical Society
• /
• v.26 no.12
• /
• pp.1975-1980
• /
• 2005

A series of substituted rutaecarpines were prepared by employing Fischer indole synthesis as key step and their inhibitory activities on COX-1 and 2 as well as selectivity on COX-2 were evaluated. The compounds with a methanesulfonyl and a bromo group at C10 showed promising inhibitory activity ($IC_{50}$ = 0.27, 0.35 $\mu$M, respectively) with selectivity.

• Journal of the Korean Data and Information Science Society
• /
• v.4
• /
• pp.1-11
• /
• 1993

The Cox's regression model is frequently used for covariate effects in survival data analysis, But, much of the statistical work has focused on asymptotic behavior so the small sample evaluation has been neglected. In this paper, we compare the small or moderate sample performances of the survival function estimators for the Cox's regression model using bootstrap method. The smoothed PL type estimator and the Link estimator are slightly better than corresponding the PL type estimator and the Nelson type estimator in the sense of the achieved error rates.

• Journal of the Korean Data and Information Science Society
• /
• v.19 no.3
• /
• pp.789-800
• /
• 2008

Current credit evaluation models based on financial data make use of smoothing estimated default ratios which are transformed from each financial variable. In this work, some problems of the credit evaluation models developed by financial experts are discussed and we propose improved credit evaluation models based on the stepwise variable selection method and Box-Cox transformed data whose distribution is much skewed to the right. After comparing goodness-of-fit tests of these models, the validation of the credit evaluation models using statistical methods such as the stepwise variable selection method and Box-Cox transformation function is explained.

• The Korean Journal of Applied Statistics
• /
• v.19 no.2
• /
• pp.283-290
• /
• 2006

Generally speaking, power transformations such as Box-Cox transformation(1964) is applied for variance stabilization and symmetry. But, when the distribution of the original data has a large mean with a small variance or the coefficient of variation is very small, they don't work at all. This paper propose a simple method to introduce a shift parameter before applying power transformations and showed the numerical evidence by Monte Carlo simulation and a real data analysis.

• Proceedings of the Korean Statistical Society Conference
• /
• 2002.11a
• /
• pp.197-201
• /
• 2002

The healthy worker effect is an important issue in occupational epidemiology. We proposed a new statistical method to test the relationship between exposure and time to death in the presence of the healthy worker effect. In this study, we considered the healthy worker hire effect to operate as a confounder and the healthy worker survival effect to operate as a confounder and an intermediate variable. The basic idea of the proposed method reflects the length bias-sampling caused by changing one's employment status. Simulation studies were also carried out to compare the proposed method with the Cox proportional hazards models. According to our simulation studies, both the proposed test and the test based on the Cox model having the change of the employment status as a time-dependent covariate seem to be satisfactory at an upper 5% significance level. The Cox models, however, are inadequate with the change, if any, of the employment status as time-independent covariate. The proposed test is superior in power to the test based on the Cox model including the time-dependent employment status.

• Korean Journal of Pharmacognosy
• /
• v.31 no.1
• /
• pp.57-62
• /
• 2000

By bioassay-guided fractionation followed by chromatographic separation of the MeOH extract of Alpinia Rhizome, five COX-2 inhibitors were isolated and characterized as pinocembrin, galangin 3-methyl ether, galangin, kaempferid, and 5-hydroxy-7-(4'-hydroxy-3'-methoxyphenyl)-1-phenyl-3-heptanone.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.347.4-348
• /
• 2002

Recently it has been demonstrated that selective cyclooxygenase-2 (COX-2) inhibitors retain the antiinflammatory effect but with markedly reduced GI toxicity compared to non selective inhibitors such as traditional NSAIDs. As a consequence, intense efforts have been made to develop selective COX-2 inhibtors during the last decade. Two compounds in this class. celecoxib and rofecoxib. are already in the market and are proved as potent and selective COX-2 inhibitors with much better gastric tolerance. However. there are still strong domands for a COX-2 inhibitor with improved efficacy and safety profiles. Here we report the synthesis and biological profiles of 1.5- and 4.5-disubstituted imidazole analogues as structural equivalents of cefecoxib and refecoxib. The imidazole analogues are overlapped well whth the 3D srructures of celecoxib and rofecoxib.

• YAKHAK HOEJI
• /
• v.48 no.2
• /
• pp.135-140
• /
• 2004

For the development of new COX-2 inhibitors, 1,5-diarylhydantoins 5a∼5c and 1,5-diaryl-2-thiohydantoin 6a∼6c were synthesized from commercially available phenylacetic acids through esterification, bromination, C-N bond formation and cyclization. Esters 2a∼c were efficiently synthesized from the starting materials 1a∼c by refluxing in absolute methanol for 3 hours with catalytic concentrated sulfuric acid. Bromination of 2a∼c was carried out with use of N-bomosuccinimide at rt in dichloromethane. The bromine of 3a∼c was substituted with aniline in ethanol or N,N-dimethylformamide to provide 4a∼c. Hydantoins and 2-thiohydantoins were synthesized from 4a∼c by treatment of potassium isocyanate or potassium thiocyanate in dil-ethanol with triethylamine.