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Foreign Aid and Donor's Exports to the Recipients: The South Korean Case
Yunhee Choi(Yunhee Choi) 한국학술연구원 2022 Korea Observer Vol.53 No.4
This paper examined the relationship between foreign aid and export, for the case of Korea from 1965 to 2015. I argue that foreign aid promotes donor's export to the recipient for following reasons: (1) the explicit and implicit tied-aid agreements directly increase export; and (2) implementing aid policy involves transferring not only money but also people. Thus, it serves as building the political, economic, and social relationships between donor and recipient countries. Those spillover effects of foreign aid can increase the export of donor countries. By applying a dynamic gravity model with GMM estimators, I provided empirical evidence that Korean bilateral ODA is positively related to its export to the recipients. The result showed that the impact of Korean ODA on its exports is positive and more significant in the post-1990s. In specific, for the later period, a percentage increase in Korean bilateral aid is associated with 0.095% increase in export in the short-term and 0.22% increase in export in the long run.
Temporal Changes of Lung Cancer Mortality in Korea
Choi, Yunhee,Kim, Yeonju,Hong, Yun-Chul,Park, Sue Kyung,Yoo, Keun-Young The Korean Academy of Medical Sciences 2007 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.22 No.3
<P>The lung cancer mortality in Korea has increased remarkably during the last 20 yr, and, it has become the first leading cause of cancer-related deaths since 2000. The aim of the current study was to examine time trends of lung cancer mortality during the period 1984-2003 in Korea, assessing the effects of age, period, and birth cohort. Data on the annual number of deaths due to lung cancer and on population statistics from 1984 to 2003 were obtained from the Korea National Statistical Office. A log-linear Poisson age-period-cohort model was used to estimate the effects of age, period, and birth cohort. The both trends of male and female lung cancer mortality were both explained by age-period-cohort models. The risks of lung cancer mortalities for both genders were shown to decline in recent birth cohorts. The decreasing trends begin with the 1939 birth cohort for men and 1959 for women. The mortality pattern of lung cancer was dominantly explained by a birth cohort effect, possibly related with the change in smoking pattern, for both men and women. Finally, the mortality of lung cancer in Korea is expected to further increase in both men and women for a while.</P>
Choi Yunhee,Pandey Bhawana,Li Xiao‐Xi,Lee Yong‐Min,Cho Kyung‐Bin,Nam Wonwoo 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.11
Density functional theory calculations were performed to study the Lewis acid (Sc3+) effects on the reactivity of ultrahigh-valent chromium-oxo species toward both C H bond activation and sulfoxidation reactions. Calculations confirm that the oxidizing power of chromium-oxo species is enhanced by binding Sc3+ ion. In sulfoxidation reactions, especially, binding Sc3+ ion enhances the redox potential of the chromium-oxo species, whereby the activation barrier is decreased dramatically. The details of the reactions obtained by theory are disclosed in this work.
Choi Yunhee,Kim Yong-Hak 한국미생물학회 2022 The journal of microbiology Vol.60 No.4
Bacillus velezensis strain GH1-13 contains a (2R,3R)-butanediol dehydrogenase (R-BDH) BdhA which converts acetoin to R-BD reversibly, however, little is known about its regulatory cysteine and biological significance. We performed sitedirected mutation of three cysteines in BdhA. The C37S mutant had no enzyme activity and the C34S and C177S mutants differed from each other and wild type (WT). After zinc affinity chromatography, 1 mM ZnCl2 treatment resulted in a 3-fold enhancement of the WT activity, but reduced activity of the C34S mutant by more than 2 folds compared to the untreated ones. However, ZnCl2 treatment did not affect the activity of the C177S mutant. Most of the double and triple mutant proteins (C34S/C37S, C34S/C177S, C37S/C177S, and C34S/C37S/C177S) were aggregated in zinc resins, likely due to the decreased protein stability. All of the purified WT and single mutant proteins increased multiple intermolecular disulfide bonds in the presence of H2O2 as the buffer pH decreased from 7.5 to 5.5, whereas an intramolecular disulfide bond of cysteine 177 and another cysteine in the CGIC motif region was likely formed at pH higher than pKa of 7.5. When pH varied, WT and its C34S or C177S mutants reduced acetoin to R-BD at the optimum pH 5.5 and oxidized R-BD to acetoin at the optimum pH 10. This study demonstrated that cysteine residues in BdhA play a regulatory role for the production of acetoin and R-BD depending on pH as well as metal binding and oxidative stress.
Age-period-cohort analysis of female Breast Cancer mortality in Korea
Choi, Yunhee,Kim, Yeonju,Park, Sue Kyung,Shin, Hai-Rim,Yoo, Keun-Young Springer-Verlag 2006 Breast cancer Vol.13 No.3
<P>Background: Although breast cancer in women remains relatively rare in Korea, its incidence and mortality figures are increasing, consistent with the increasing risk observed in successive generations of Korean women. The aim of the current study was to examine time trends of breast-cancer mortality during the period 1984-2003 in Korea, assessing the importance of the effects of age, period and birth cohort as risk factors.Methods: Data on the annual number of deaths due to female breast cancer and on female population statistics from 1984 to 2003 were obtained from the Korean National Statistical Office. A log-linear Poisson age-period-cohort model was used to estimate age, period and cohort effects.Results: The trend of breast cancer mortality was explained by an age-cohort model based on goodness of fit, even though the significance of the cohort effect was marginal (p=0.08) after adjusting for age. The risk of breast cancer death was found to increase with age after adjusting for the cohort effect, and it was different from the cross-sectional age curve. Also, breast cancer mortality increased along with the birth cohort.Conclusions: Even though the cohort effect was found to have a marginally significant effect on breast cancer mortality, it is expected to be more significant in the future given the recent on-going changes in diet and reproductive behavior shown by Korean women.</P>