• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.4
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• pp.323-335
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• 1983

The inhibitory effects of the extract and crude saponin of red and white ginsengs on lipoperoxide formation in vitro and in vivo were studied and correlated with anti-aging. To this end, antioxidant activity, induction period and lipoperoxide were measured by the methods of EDA, POV and TBA value. And also superoxide dismutase and peroxidase activity were measured by pyrogallol autoxidation method (${\Delta}A$ 420/min) and initial velocity(${\Delta}A$ 436/min), respectively. From HPLC analysis, the PT/PD ratio of red and white ginsengs was found to be 0.561% and 0.401%, respectively, and red ginseng increased the PT/PD ratio in comparison with white ginseng. The EDA activity of red ginseng was higher than that of white ginseng; red ginseng showed stronger antioxidative effect than white ginseng. The inhibitory effect of red ginseng was lower than that of white ginseng during the induction period. It was proved that high molecular coloring substance was deeply related to the initial stage of lipoperoxidation. There was no significant difference between red and white ginsengs in both in vitro and intraperitoneal administration experiments, and red ginseng was more effective than white ginseng in longterm administration. And also inhibitory effect on lipoperoxide formation was mainly occurred in liver, suggesting that the function of liver played an important role in anti-aging actions. From the measurement of superoxide dismutase(SOD) activity for both ginseng groups intraperitoneally and orally administered, it was found that red ginseng group administered extract and crude saponin showed remarkable inhibitory effects in comparison with white ginseng. In particular, orally administered group showed more stronger inhibitory effect on lipid peroxidation in comparison with intraperitoneally administered group. It was also found that the continuous oral administration was more effective than temporary administration. Red ginseng was more notable anti-aging effect in comparison with white ginseng in vivo, and this may be due to the increase of SOD activity in rat-liver. Peroxidase activity also showed similar trend to SOD activity in vitro and in vivo experiments. Red ginseng was not only superior to white ginseng for preservation but also for biochemical and pharmaceutical efficacy.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.1
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• pp.85-88
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• 2015

This study attempted to establish an HPLC analysis method for determination of marker compounds as a part of material standardization for the development of health functional food materials from Perilla frutescens Britton var. acuta Kudo. The quantitative determination method of rosmarinic acid as a marker compound of P. frutescens Britton var. acuta Kudo extract (PFE) was optimized by HPLC analysis using a C18 column ($4.6{\times}150mm$, $5{\mu}m$) with 0.1% acetic acid as the elution gradient and methanol as the mobile phase at a flow rate of 1 mL/min and detection wavelength of 280 nm. The HPLC/UV method was applied successfully to quantification of the marker compound in PFE after validation of the method with linearity, accuracy, and precision. The method showed high linearity in the calibration curve at a coefficient of correlation ($R^2$) of 0.9995, and the limit of detection and limit of quantitation were $0.36{\mu}g/mL$ and $1.2{\mu}g/mL$, respectively. Relative standard deviation (RSD) values of data from intra- and inter-day precision were less than 3.21% and 1.43%, respectively. Recovery rate test at rosmarinic acid concentrations of 12.5, 25 and $50{\mu}g/mL$ scored between 97.04~98.98% with RSD values from 0.25~1.97%. These results indicate that the established HPLC method is very useful for the determination of marker compound in PFE to develop a health functional material.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1133-1138
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• 2006

Smilax china root has been used as traditional medicinal remedy in China and Korea and reported to have various biological activities such as anti-inflammatory, antimutagenic and antimicrobial activities. In this study, the possibility of development as natural antioxidants of Smilax china root extracts was investigated. For the evaluation of antioxidant activity, aqueous- and 25% EtOH extract from Smilax china root were prepared and six different evaluation assay methods, i.e., measurement of total phenolics, radical scavenging effects on 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitric oxide (NO) and nitrite $(NO_2)$, reducing power, and inhibitory effect on tyrosinase activity, were used. The total phenolics content of two extracts was high as the level of 36 mg of gallic acid equivalent per 1 g of dried sample tested. The radical scavenging activities of ethanol extract toward DPPH and NO were better than those of aqueous extract (p<0.05). The $NO_2$ scavenging activity of both extracts showed the highest value at pH 1.2 (98%). Especially, the $NO_2$ scavenging activities of EtOH extract were significantly stronger than those of aqueous one at pH 4.2 (51%) and pH 6.0 (32%), respectively. In the reducing power test, both extracts revealed higher ferric ion reducing activity than known antioxidant, vitamin C at the level of $0.05\sim0.1mg/mL$ (p<0.01). The 1 mL of aqueous and 25% EtOH extract showed effective inhibition activity on tyrosinase activity as 45% and 53%, respectively. Therefore, these results suggest that two extracts from Smilax china root may serve as useful natural antioxidants.

• Journal of dental hygiene science
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• v.16 no.2
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• pp.142-149
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• 2016

The number of male dental hygienists has been continuously increasing in dental services. The purpose of this study aimed to identify the relationship between job stress, job satisfaction, and turnover intention in male dental hygienists and to provide basic data to improve their job satisfaction. The study population was 110 Korean male dental hygienists working for dental clinics or hospitals. The data were collected from November 10 to December 7, 2015. After an explanation about the objective of the study, 110 questionnaires were distributed via email, and 97 responses were analyzed using SPSS. Overall averages of job stress, job satisfaction and turnover intention in male dental hygienists were 3.05, 2.92, and 3.47 out of 5, respectively. Some sub-factors of job stress, including interpersonal relationships at the workplace and future prospects of dental clinics, were proven to have statistically significant negative influence on job satisfaction (p<0.001). Regression analysis was performed with job stress and job satisfaction as independent variables and turnover intention as a dependent variable. Results showed that job stress had a positive effect on turnover intention (p<0.01) while job satisfaction had a negative effect on turnover intention (p<0.001). Job satisfaction was revealed to have statistically significant negative influence on turnover intention (p<0.001). Some of sub-factors of job stress, including work environment and future prospects of dental clinics and professional position, had a positive effect on turnover intention (p<0.05). The study showed that higher job stress led to higher turnover intention, and higher job satisfaction led to lower turnover intention. Accordingly, job stress and job satisfaction are critical factors for turnover intention in male dental hygienists.

• Journal of The Korean Ophthalmological Society
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• v.58 no.11
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• pp.1260-1268
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• 2017

Purpose: Strabismus affects any age and represents various functional or non-functional eye problems. This population-based study was conducted to determine the prevalence of strabismus and nystagmus in South Korea according to various sociodemographic factors. Methods: We acquired data from the Korea National Health and Nutrition Examination Survey, a nation-wide cross-sectional survey and examinations of the non-institutionalized civilian population in South Korea (n = 30,538), conducted from July 2008 to December 2011. The prevalence of strabismus and nystagmus were verified, and associated sociodemographic factors was evaluated. Results: The overall prevalence of strabismic disorder in participants over 3 years of age was $1.4{\pm}0.1%$ (95% confidence interval [CI] 1.3-1.6%; $1.5{\pm}0.1%$ in males, $1.3{\pm}0.1%$ in females). The prevalence of exodeviation (15 or more prism diopters), esodeviation (10 or more prism diopters), vertical deviation, and other complicated strabismus and nystagmus was 1.0%, 0.2%, 0.2%, 0.1% and 0.1% respectively. The prevalence was highest in the 6 to 15-year age group ($1.9{\pm}0.3%$), and lowest in the 40 to 49 years age group ($0.8{\pm}0.1%$) (p = 0.005). There were no statistically significant differences for gender, region, residential area, household income, educational level and occupation. Conclusions: This nation-wide epidemiologic study demonstrated that the prevalence of strabismus and nystagmus according to various sociodemographic factors in South Korea was not statistically significant except for age group. Further investigations are required based on more surveys to better recognize the etiologic or risk factors that may be related to strabismus and nystagmus.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.649-653
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• 2009

"Cheongan" is a new japonica rice variety developed from a cross between SR15225-B-22-1-2-1 and Iksan431 in summer season, 1997 by National Institute of Crop Science, RDA. The line SR15225-B-22-1-2-1 has good canopy architecture and multi-disease and insect resistance, and Iksan431 has translucent milled rice and good eating-quality. Heading date of Cheongan is August 13 in central lowland and mid-mountainous areas. "Cheongan" having culm length of 84 cm shows relatively semi-erect pubescent leaf blade and rigid culm, tolerance to lodging with and good canopy architecture. This variety has 14 tillers per hill and 126 spikelets per panicle. It shows tolerance to heading delay and spikelet sterility comparable to Hwaseongbyeo when exposed to cold stress. Leaf senescence of Cheongan progresses slowly during the ripening stage and the viviparous germination ratio was 59 %, similar to that of Hwaseongbyo. "Cheongan" shows moderately resistance to blast disease, but susceptible to stripe virus and brown planthopper. The milled rice of "Cheongan" exhibits translucent, clear non-glutinous endosperm and medium short grain. It shows similar amylose content of 18.7%, gelatinization temperature, and similar palatability of cooked rice compared to Hwaseongbyeo. The milled rice yield of this cultivar is about 5.54 MT/ha at ordinary season culture in local adaptability test for three years. Especially, "Cheongan" has better milling properties of higher 98.4% and 73.9% in the percentage of head rice in milled rice and milling recovery of head rice, respectively, than those of Hwaseongbyeo. "Cheongan" could be adaptable to the central and mid-southern plain area, and mid-western coastal area of Korea.

• Korean Journal of Breeding Science
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• v.43 no.6
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• pp.519-523
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• 2011

''Nokyang', a new high biomass yield and whole crop silage rice (Oriza sativa L.) cultivar, was developed by the rice breeding team of National Institute of Crop Science, RDA, Suwon, Korea, during the period from 1996 to 2006 and released in 2007. It was derived from a cross between Yongmoonbyeo/IR67396-16-3-3-1. This cultivar has about 130 days of growth duration from seeding to heading and is tolerance to lodging with erect pubescent leaves, semidwarf (culm length 78 cm) and thick culm. This cultivar has less tillers per hill and more spikelet numbers per panicle than Dasanbyeo. 'Nokyang' has wide and stay green leaf compared other Tongil-type varieties. This new variety is resistant to grain shattering and to some disease including bacterial leaf blight and stripe virus. This variety has good qualities for whole crop silage with high TDN (Total Digestive Nutrient) yield and low NDF (Neutral Detergent Fiber) and low ADF (Acid Detergent Fiber) and high RFV (Relative Feed Value) compared to common high grain yield varieties. The biomass and TDN yield performance of 'Nokyang' is 1,652 MT/ha, 9.9 MT/ha, individually in local adaptability test for three years. 'Nokyang' is adaptable to central plain area, south-eastern plain area of Korea.

• Food Science and Preservation
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• v.12 no.4
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• pp.310-316
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• 2005

This study was carried out to investigate the quality characteristics by packaging materials and storage temperature to predict safe storage period for milled rice. Mechanical taste value and whiteness of milled rices stored at room temperature were severely decreased than those of the stored at low temperature, but fat acidity and b value of those at room temperature was rapidly increased than those of stored at low temperature. Milled rice packed in LDPE film bag were smelled stale flavor after 4 months storage at room temperature, Hojinbyeo was not produced flour in the rice grain surface but Dongjinbyeo was showed production of flour. pH of milled rice of Dongjinbyeo and Hojinbyeo packed in LDPE film bag were the lowest showing 5.3 and 5.6, respectively after 6 months at mom temperature. Safe storage period of Dongjinbyeo and Hojinbyeo packed in craft paper bag were 1 month at room temperature, those of packed in LDPE film bag were 2 months. At low temperature safe storage period of Dongjinbyeo and Hojinbyeo packed in craft paper bag were 2 months, those of packed in LDPE film bag were 5 and 4 months, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.2
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• pp.92-100
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• 2005

This study was conducted to find suitable methods for screening organic resources useful for compost. Twenty-seven industrial and domestic sludges were collected from various cities and industrial areas. Contents of organic matters in the sludges were in the range of 79.3-98.0%, and the contents were much higher than the regulation level (60%) for raw materials of compost. Contents of total nitrogen were in the range of 0.8-2.6%. Contents of Fe and Al were very high. Content of HEM was highest in textile sludge ($257mg\;kg^{-1}$) and the contents in the others were in the range of $12.6-90.3mg\;kg^{-1}$. Content of PAHs was lowest in food sludge ($739.1{\mu}g\;kg^{-1}$ and pulp-mill sludge had the highest PAHs content ($3461.8{\mu}g\;kg^{-1}$). $Microtox^{(R)}$ $EC_{50}$ values were higher in the sludges which were classified as a possible material in composting after analysis and investigation. Lettuce root elongation and $EC_{50}$ values were relatively lower in pulp-mill sludge, sewage sludge 3 (Large city), food sludge and leather sludge. Therefore, mineral nutrients, heavy metals, organic compounds (HEM, PAHs, PCBs), and bioassay ($Microtox^{(R)}$ $EC_{50}$, Relative root elongation test) are recommended to be included in the screening system of raw material of compost in addition to the current regulation with organic matter and 8 heavy metals.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.354-363
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• 2007

In order to investigate the optimum rate and interval of silicate fertilizer application for rice cultivation, Chucheong byeo variety, one of commonly cultivated rice cultivar in Korea was planted on two different wetland rice soils located on Hwaseong-si from 2002 to 2005; Jisan series(a member of the fine loamy, mixed, mesic family of Fluvaquentic Endoaquepts), known as "Productive Paddy Soil", without any conspicuous limiting factor, and Seokcheon series (a member of the coarse loamy, mixed, nonacid, mesic family of Fluvaquentic Endoaquetps), known as "Sandy Paddy Soil", sandiness being major limiting factor. There were three rate treatments of silicate fertilizer application; the amount of silicate fertilizers needed to adjust the available soil silicate contents to 130, 200, and $270mg\;kg^{-1}$ was applied, in the first year only. There was an additional plot; applying the amount of silicate fertilizer needed to adjust soil available silicate to 130 ppm every year, which would serve as the base for the evaluation of residual effects of silicate fertilizers in the plots where different rates of silicate fertilizer were applied. From the yield data in first year, it was found that optimum available silica in the soil are $154mg\;kg^{-1$ and $160mg\;kg^{-1}$, in Jisan and Seogcheon soils, respectably. The duration of residual effects of silicate fertilizer was different depending upon the amount of applied silicate fertilizers and the soils. The higher the application rate, the residual effect lasted longer, and the residual effect was lasted longer in Jisan(clay loam) soil than in Seogcheon(sandy loam) soil. During four years, sum of the rate of contribution to increase available soil silica of applied silicate fertilizer in different soils ranged 18.6% and 24.1% in Jisan soil and Seogcheon soil, respectively. This may suggest that much portion of applied silicate would be either lost from the soil or remain in the soil as insoluble form. This deserves further study.