• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.349-359
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• 2017

In this paper, we conducted survival analyses by fitting the Cox proportional hazards model to stage III proximal colon cancer data obtained from the Surveillance, Epidemiology, and End Results program of the National Cancer Institute. We investigated the effect of covariates on the hazard function for death from proximal colon cancer in stage III with surgery performed and estimated the survival probability for a patient with specific covariates. We showed that the proportional hazards assumption is satisfied for covariates that were used to analyses, using a test based on the Schoenfeld residuals and plots of the Schoenfeld residuals and $log[-log\{{\hat{S}}(t)\}]$. We evaluated the model calibration and discriminatory accuracy by calibration plot and time-dependent area under the ROC curve, which were calculated using 10-fold cross validation.

• Journal of the Korean Chemical Society
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• v.51 no.1
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• pp.21-30
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• 2007

A multiwavelength spectrophotometric titration method was applied to study protolytic constants of four water-soluble vitamins, folic acid(vitamin B9 or B0), thiamine(vitamin B1), riboflavin(vitamin B2) and pyridoxal (vitamin B6) in binary ethanol-water mixtures at 25oC and an ionic strength of 0.1M NaNO3. The protolytic equilibrium constants, spectral profiles, concentration diagrams and also the number of components has been calculated from the curve fitting of the pH-absorbance data with appropriate mass balance equations by an established factor analysis model. DATAN program was used for determination of acidity constant and SPECFIT program was used for calculation of standard deviations and partial correlation coefficients. A glass electrode calibration procedure based on the four parameter equation pH=α+SpcH+JH+[H+]+ JOH-Kw/[H+] based on the Gran,s plots was used to obtain pH-readings in the concentration scale (pcH). The effect of the solvent on the protolytic constants was discussed.

• Korean Journal of Psychosomatic Medicine
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• v.23 no.2
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• pp.114-120
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• 2015

Objectives : This study aimed to investigate the risk factors of depression for patients with tuberculosis(TB). Methods : A total of 57 patients with TB were recruited. All participants completed the Becks Depression Inventory-II for evaluating depressive symptoms. The risk factor for depression was analyzed by binary logistic regression analysis. Nomogram was performed for probability of depression. Results : Low body mass index(BMI, OR 0.801, 95% CI 0.65, 0.98), interruption of treatment for TB(OR 5.908, 95% CI 1.19, 29.41), past history of depression(OR 24.653, 95% CI 1.99, 308.44) were associated with increased risk for depression. The calibration curve for predicting probability of survival showed a good agreement between the nomogram and actual observation(Original C-index=0.789, bias corrected C-index=0.754). Conclusions : The result of the present study indicate that low BMI, interruption of treatment for TB, and past history of depression were risk factors for depression in patients with TB. The psychiatric intervention may be needed to prevent depression if the patients with TB have risk factor during treatment for TB.