• Journal of Astronomy and Space Sciences
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• v.26 no.2
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• pp.141-156
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• 2009

Through the photometric observations of the near-contact binary, XZ CMi, new BV light curves were secured and seven times of minimum light were determined. An intensive period study with all published timings, including ours, confirms that the period of XZ CMi has varied in a cyclic period variation superposed on a secular period decrease over last 70 years. Assuming the cyclic change of period to occur by a light-time effect due to a third-body, the light-time orbit with a semi-amplitude of 0.0056d, a period of 29y and an eccentricity of 0.71 was calculated. The observed secular period decrease of $-5.26{\times}10^{-11}d/P$ was interpreted as a result of simultaneous occurrence of both a period decrease of $-8.20{\times}10^{-11}d/P$ by angular momentum loss (AML) due to a magnetic braking stellar wind and a period increase of $2.94{\times}10^{-11}d/P$ by a mass transfer from the less massive secondary to the primary components in the system. In this line the decreasing rate of period due to AML is about 3 times larger than the increasing one by a mass transfer in their absolute values. The latter implies a mass transfer of $\dot{M}_s=3.21{\times}10^{-8}M_{\odot}y^{-1}$ from the less massive secondary to the primary. The BV light curves with the latest Wilson-Devinney binary code were analyzed for two separate models of 8200K and 7000K as the photospheric temperature of the primary component. Both models confirm that XZ CMi is truly a near-contact binary with a less massive secondary completely filling Roche lobe and a primary inside the inner Roche lobe and there is a third-light corresponding to about 15-17% of the total system light. However, the third-light source can not be the same as the third-body suggested from the period study. At the present, however, we can not determine which one between two models is better fitted to the observations because of a negligible difference of $\sum(O-C)^2$ between them. The diversity of mass ratios, with which previous investigators were in disagreement, still remains to be one of unsolved problems in XZ CMi system. Spectroscopic observations for a radial velocity curve and high-resolution spectra as well as a high-precision photometry are needed to resolve some of remaining problems.

• Journal of Nutrition and Health
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• v.50 no.5
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• pp.415-425
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• 2017

Purpose: Many studies have suggested that neuronal cells protect against oxidative stress-induced apoptotic cell death by polyphenolic compounds. We investigated the neuroprotective effects and the mechanism of action of Momordica charantia ethanol extract (MCE) against $H_2O_2-induced$ cell death of human neuroblastoma SK-N-MC cells. Methods: The antioxidant activity of MCE was measured by the quantity of total phenolic acid compounds (TPC), quantity of total flavonoid compounds (TFC), and 2,2-Diphenyl-1-pycrylhydrazyl (DPPH) radical scavenging activity. Cytotoxicity and cell viability were determined by CCK-8 assay. The formation of reactive oxygen species (ROS) was measured using 2,7-dichlorofluorescein diacetate (DCF-DA) assay. Antioxidant enzyme (SOD-1,2 and GPx-1) expression was determined by real-time PCR. Mitogen-activated protein kinases (MAPK) pathway and apoptosis signal expression was measured by Western blotting. Results: The TPC and TFC quantities of MCE were 28.51 mg gallic acid equivalents/extract g and 3.95 mg catechin equivalents/extract g, respectively. The $IC_{50}$ value for DPPH radical scavenging activity was $506.95{\mu}g/ml$ for MCE. Pre-treatment with MCE showed protective effects against $H_2O_2-induced$ cell death and inhibited ROS generation by oxidative stress. SOD-1,2 and GPx-1 mRNA expression was recovered by pre-treatment with MCE compared with the presence of $H_2O_2$. Pre-treatment with MCE inhibited phosphorylation of p38 and the JNK pathway and down-regulated cleaved caspase-3 and cleaved PARP by $H_2O_2$. Conclusion: The neuroprotective effects of MCE in terms of recovery of antioxidant enzyme gene expression, down-regulation of MAPK pathways, and inhibition apoptosis is associated with reduced oxidative stress in SK-N-MC cells.

• Journal of Nutrition and Health
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• v.50 no.5
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• pp.426-436
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• 2017

Purpose: To compare the extent to which three different levels of D-ribose in sugar reduce the glycemic index (GI) and blood glucose response in healthy adults. Methods: Healthy adults (eight male and six female participants, n = 14) fasted for 14~16 h after eating the same dinner. Participants were then randomized to receive glucose, sucrose, sucrose containing 5% D-ribose (RB5), sucrose containing 10% D-ribose (RB10), or sucrose containing 14% D- ribose (RB14) every week on the same day for 10 weeks (repeating the sample twice). Blood samples were collected by finger prick before and 15, 30, 45, 60, 90, and 120 min after starting to eat. Results: We observed a decreased glycemic response to sucrose containing D-ribose. GIs for sucrose, RB5, RB10, and RB14 were 67.39, 67.07, 47.57, and 45.62, respectively. GI values for sucrose and RB5 were similar to those for foods with a medium GI, and GI values for RB10 and RB14 were similar to those for foods with a low GI. The postprandial maximum blood glucose rise (Cmax) with RB14 was the lowest among the test foods. Cmax values for RB10 and RB14 were significantly lower than that for sucrose. Conclusion: The results of this study suggest that sucrose containing D-ribose has an acute suppressive effect on GI and Cmax. In addition, D-ribose active elements in sugar may be effective in preventing blood glucose spikes induced by sucrose intake.

• Journal of Nutrition and Health
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• v.50 no.5
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• pp.483-493
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• 2017

Purpose: The purpose of this study was to determine trends in dietary vitamin E intakes and contributing food groups among Korean adults. Methods: This study included 66,695 subjects aged ${\geq}19years$ who completed a nutrition survey as part of the Korea National Health and Nutrition Examination Survey (1998, 2001, 2005, 2007~2009, 2010~2012, 2013~2015). We estimated individual daily intakes of ${\alpha}-$, ${\beta}-$, ${\gamma}-$, ${\delta}-tocopherol$, and total vitamin E by linking food consumption data with a vitamin E database of commonly consumed foods. Results: Daily vitamin E intake significantly increased from $6.4mg\;{\alpha}-TE/d$ in 1998 to $7.7mg\;{\alpha}-TE/d$ in 2013~2015 (p for trend < 0.0001) among men as well as from $5.4mg\;{\alpha}-TE/d$ in 1998 to $6.5mg\;{\alpha}-TE/d$ in 2013~2015 among women (p for trend < 0.0001). However, the intake of vitamin E was lower than the adequate intake (AI) of Dietary Reference Intakes for Koreans 2015 (2015 KDRI). In 2013~2015, men consumed 6.5 mg/d of ${\alpha}-tocopherol$, 0.5 mg/d of ${\beta}-tocopherol$, 6.0 mg/d of ${\gamma}-tocopherol$, and 3.9 mg/d of ${\delta}-tocopherol$, whereas women consumed 5.7 mg/d of ${\alpha}-tocopherol$, 0.4 mg/d of ${\beta}-tocopherol$, 4.8 mg/d of ${\gamma}-tocopherol$, and 2.8 mg/d of ${\delta}-tocopherol$. The major food groups contributing to vitamin E intake were vegetables (men: 23.3%, women: 22.7%), grains (men: 14.5%, women: 13.9%), and eggs (men: 13.0%, women: 12.5%). Conclusion: This study provides scientific evidence for vitamin E intake in Korean adults. Since the current intake of vitamin E was lower than the reference intakes set by 2015 KDRI, dietary vitamin E intake should be monitored regularly among Korean adults.

• Journal of Nutrition and Health
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• v.51 no.3
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• pp.215-227
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• 2018

Purpose: This study was conducted to verify the effects of increases in consuming Korean food in patients who underwent cardiovascular disease (CVD) surgery based on a Korean diet control education program and to investigate the effects of Korean diet control nutrition education on risk factors of CVD, changes in amounts of medication, and nutritional intakes. Methods: The subjects consisted of 15 patients who have undergone CVD surgery within three years and continuously taken cardiovascular drugs. The Korean traditional diet (KTD) emphasizes intake of vegetables and fermented foods to lower saturated fat and cholesterol intake. We applied a KTD education program that included a modified DASH (The dietary approaches to stop hypertension) diet for cardiovascular disease patients. Korean diet control education was then applied to the patients for 12 weeks to evaluate the risk factors of CVD and the state of nutritional intakes. Results: The Korean diet control compliance score increased significantly (p < 0.001) as Korean diet control education was implemented. Additionally, the obesity indexes, waist circumference (WC) (p = 0.002) and waist-to-hip ratio (WHR) decreased significantly (p < 0.001) after subjects received the education. Moreover, the glycemic control index, HbA1c, was significantly decreased (p < 0.05) from $7.3{\pm}1.0%$ before the education to $7.0{\pm}1.1%$ after the education. Changes in the amounts of Korean diet intake consisted of significant increases in cooked rice with whole grains, narmuls (vegetables either raw or cooked), kimchi, and traditional fermented foods following the education. Moreover, the nutritional intake after the education showed significant decreases (p < 0.05) in animal protein, animal lipids, and cholesterol. However, the intakes of Na, K, dietary fiber, vitamin A, vitamin $B_6$, vitamin C, and folic acid were significantly increased. Conclusion: The active encouragement of consuming Korean food and the intervention of implementing diet control education positively affected nutritional intake, the obesity index and glycemic control of patients who have undergone CVD surgery.

• Journal of Applied Biological Chemistry
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• v.57 no.2
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• pp.145-152
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• 2014

To evaluate the improving effects of antioxidant activity, we observed antioxidant capacities such as electron donating ability (EDA), Ferric reducing antioxidant power (FRAP), inhibitory activity of xanthine oxidase (XO) and aldehyde oxidase (AO), and sensory characteristics on mixture of Smilax china L. root water extract added with water extract of fermented S. china L. leaf by Aspergillus oryzae (FSCL). Those contents of mixture with higher ratio of FSCL were proportionally high. And OD475 of mixture with higher ratio of FSCL was almost proportionally high ($R^2=0.9850$). Antioxidant capacities of EDA and FRAP of the mixture was higher than that of non-mixture. In addition, XO inhibitory activity ($IC_{50}$) of A (1.19) was 59.80% higher than that of F (2.96), and the activity of mixture by the higher ratio of FSCL was proportionally low ($R^2=0.9490$). Taste acceptability of A was slightly higher than that of F, whereas that of C was highest. And color acceptability of 40-80% mixture was higher than those of A, F, and B. Overall acceptability of C and D was highest than those of others. Moreover, hot water extract of S. china L. leaf fermented with A. oryzae was maroon color, which looks like Puerh tea style, and mixture of S. china L. root extract added with hot water extract of S. china L. leaf was high acceptability of beverage. These results suggest that mixture of extract of S. china L. root and hot water extract of S. china L. leaf fermented with A. oryzae could improve antioxidant activities.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.2
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• pp.116-124
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• 2006

Remarkable winter season warming has been observed in East Asian countries during the last century. Accordingly, significant effects on dormancy and the resulting budburst of deciduous trees are expected. However phenological observations are rare and insufficient compared with the long-time climate records in the same region. A chill-day accumulation, which can be estimated from daily maximum and minimum temperature, is expected to make a reasonable proxy for dormancy depth of temperate zone fruit trees. To simulate dormancy depth during 1921-2004, a chill-day model parameterized for 'Campbell Early' grapevine, which is the major cultivar grown virtually anywhere in South Korea, was applied to daily temperature data at 8 locations in South Korea. The calculations showed that the chilling requirement for breaking endo-dormancy of this grapevine cultivar can be satisfied by mid-January to late February in South Korea, and the date was delayed going either northward or southward from the 'Daegu-Jeonju' line crossing the middle of South Korea in the east-west direction. Maximum length of the cold tolerant period (the number of days between endo-dormancy release and forced dormancy release) showed the same spatial pattern. When we divide the 83 years into 3 periods (I: 1921-1950, II: 1951-1980, and III: 1981-2004) and get the average of each period, dormancy release date of period III was accelerated by as much as 15 days compared with that of period I at all locations except Jeju (located in the southernmost island with subtropical climate) where an average15-day delay was predicted. The cold- tolerant period was also shortened at 6 out of 8 locations. As a result, budburst of 'Campbell Early' in spring was accelerated by 6 to 10 days at most locations, while inter-annual variation in budburst dates was increased at all locations. The earlier budburst after the 1970s was due to (1) warming in winter resulting in earlier dormancy release (Incheon, Mokpo, Gangneung, and Jeonju), (2) warming in early spring accelerating regrowth after breaking dormancy (Busan and Jeju), and (3) both of them (Seoul and Daegu).

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.3
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• pp.123-139
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• 2011

It is expected that identification and lists of $C_4$ plants in specific regions are useful not only for the ecological researches that are related to vegetation phenology and succession but also as an index of climate change. In this review, $C_4$ plants growing in South Korea were listed and their life forms were investigated. In addition, we discussed the influences that climatic change and the $C_4$ plants exerted on plant ecosystem. Photosynthetic pathway types ($C_3$ and $C_4$) for the plant species in South Korea were determined by reviewing the scientific literatures published between 1971 and 2010. Of the total 4476 species in 1123 genera and 197 families, 206 species (4.6%) in 84 genera (7.5%) and 21 families (10.7%) were identified as $C_4$ plants (including $C_3$-$C_4$ intermediate plants). Among the identified $C_4$ species, 53 species (25.7%) in 26 genera and 15 families were classified as Dicotyledoneae, while 153 species (74.3%) in 58 genera and 6 families were classified as Monocotyledoneae. The majority of the $C_4$ species belong to four families: Chenopodiaceae (15 species), Amaranthaceae (13 species), Gramineae (102 speceis) and Cyperaceae (45 species). With respect to life form composition of 206 $C_4$ species, Th-$R_5$-$D_4$-t was most dominant: 95 species (46.1%) were included in Th, 123 species (59.7%) in $R_5$, 179 species (86.9%) in $D_4$, and 122 species (59.2%) in t. The projected increase in temperature due to climate change may provide better conditions for the growth of $C_4$ plants. Such a result will have considerable impacts on the interspecific competition between $C_3$ and $C_4$ plants, the distribution of $C_4$ plants, plant phenology, and plant diversity.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.3
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• pp.148-156
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• 2011

The purpose of this study is to analyze the patterns of forest fire possibly related with Asian dust event and carry out a correlation analysis between forest fire occurrence and existence or not of the Asian dust event during dry seasons i.e. February to May in 2000 to 2008. To study the correlation of forest fire and Asian dust, we surveyed information of Asian dust observations, forest fire statistics, fire danger rating index, weather data such as temperature, relative humidity and wind speed of the day occurring the forest fire. As a consequence of analysis, the regional frequency of Asian dust was the highest in Gyeonggi and Chungbuk divisions. Frequencies of forest fire occurrence by the Asian dust events were the highest in the day before three days of the Asian dust event. The highest frequent regions of forest fire occurrence were district of boundary line between Gyeonggi and Western of Gangwon, Chungbuk and Gyeonbuk inland. The correlation between forest fire and fire danger rating index showed the high correlation with the day before three days and after three days of the Asian dust event. These correlation coefficients were 0.50038 and 0.53978 to 1% significance level. The result of analysis between the frequency of forest fire occurrence and wind speed had a highly negative relationship at all the Asian dust days, the day before and after three days. The correlation coefficients had been -0.58623 to -0.61245 to 1% significance level. Relative humidity showed a little of negative relationship with forest fire occurrence in -0.2568(p ${\leq}$ 0.01) for the Asian dust day and -0.35309(p ${\leq}$ 0.01) for next three days. Moreover, at the day before three days of Asian dust events, it was -0.23701 to 1% significance level. However, the mean temperature did not correlate with frequency of forest fire occurrence by Asian dust events at all.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.4
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• pp.192-205
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• 2009

The unexpected wind over the Mt. Hwawang on 9 February 2009 was deadly when many spectators were watching a traditional event to burn dried grasses and the fire went out of control due to the wind. We analyzed the fatal wind based on wind flow simulations over a digitized complex terrain of the mountain with a localized heating area using a three dimensional computational fluid dynamics model, CFD_NIMR_SNU (Computational Fluid Dynamics_National Institute of Meteorological Research_Seoul National University). Three levels of fire intensity were simulated: no fire, $300^{\circ}C$ and $600^{\circ}C$ of surface temperature at the site on fire. The surface heat accelerated vertical wind speed by as much as $0.7\;m\;s^{-1}$ (for $300^{\circ}C$) and $1.1\;m\;s^{-1}$ (for $600^{\circ}C$) at the center of the fire. Turbulent kinetic energy was increased by the heat itself and by the increased mechanical force, which in turn was generated by the thermal convection. The heating together with the complex terrain and strong boundary wind induced the unexpected high wind conditions with turbulence at the mountain. The CFD_NIMR_SNU model provided valuable analysis data to understand the consequences of the fatal mountain fire. It is suggested that the place of fire was calm at the time of the fire setting due to the elevated terrain of the windward side. The suppression of wind was easily reversed when there was fire, which caused updraft of hot air by the fire and the strong boundary wind. The strong boundary wind in conjunction with the fire event caused the strong turbulence, resulting in many fire casualties. The model can be utilized in turbulence forecasting over a small area due to surface fire in conjunction with a mesoscale weather model to help fire prevention at the field.