• Korean Journal of Ecology and Environment
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• v.35 no.3 s.99
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• pp.152-159
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• 2002

The seasonal variations of nitrifying bacterial population sampled from 3 sites in Moon-Chon reservoir were analyzed by in situ hybridization with fluorescently labeled rRNA-targeted oligonucleotide probes from August 2000 until July 2001. In addition, physico-chemical parameters such as temperature, pH, chi-a and DOC were measured to determine correlations between those factors and the size of nitrifying bacterial populations. Total bacterial numbers varied in the range of $0.8{\sim}1.5{\times}10^6\;cells/ml$ independent of sites and had the maximal values in March at all 3 stations. The ratio of eubacteria to total bacteria ranged from 44.9% to 79.5%, and the ratio of each nitrifying bacteria to eubacterial numbers reached only $1.0{\sim}7.4%$. The variations of ammonia-oxidizing bacteria ranged from $1.1{\times}10^4$ to $3.0{\times}10^4\;cells/ml$ without noticeable peak values whereas those of nitrite-oxidizing bacteria varied in $1.3{\sim}5.7{\times}10^4\;cells/ml$ with the increasing tendency in winter regardless of the sites. Moreover it was observed that the numbers of nitrite-oxidizing bacteria were higher than those of ammonia-oxidizing bacteria. Total bacterial numbers correlated with water temperature (r = 0.355, p<0.05) and DOC (r = 0.58G, p<0.01) positively whereas nitrite-oxidizing bacteria correlated with temperature (r = -0.416, p<0.05) and pH (r = -0.568, p = 0.001) negatively. In addition, DOC represented good correlations with eubacterial numbers (r = 0.448, p<0.01). These results indicate that temperature, DOC and pH might be one of the main factors affecting variations of bacterial populations in the aquatic ecosystem. It was also suggested that FISH method is a useful tool for detection of slow growing nitrifying bacteria.

• Korean Journal of Ecology and Environment
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• v.48 no.2
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• pp.108-114
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• 2015

Single - and combined effects of a domestic freshwater bivalve Unio douglasiae (7.6~8.6 cm in shell length) and zooplankton Daphnia magna (1~2 mm in body size) were examined to understand whether they inhibit the growth of harmful cyanobacterial bloom (i.e. Microcystis aeruginosa) in a eutrophic lake. The experiments were triplicated with twelve glass aquaria (40 L in volume); three aquaria without mussel and zooplankton, served as a control, three zooplankton aquaria (Z, density=40 indiv. $L^{-1}$), three mussel aquaria (M, density=0.5 indiv. $L^{-1}$), and three mussel plus zooplankton aquarium (ZM, density=40 indiv.Z $L^{-1}$ plus 0.5 indiv.M/L), respectively. Algal growth inhibition (%) calculated as a difference in the concentration of chlorophyll-a (Chl-a) before and after treatment. Chl-a in all aquaria decreased with the time, while a greatest algal inhibition was seen in the ZM aquaria. After 24 hrs of incubation, Chl-a concentration at the mid-depth (ca. 15 cm) in ZM aquaria reduced by 90.8% of the control, while 63.2% and 79.8% in Z and M aquaria, respectively. Interestingly, during the same period, the surface Chl-a was diminished by 51.9% and 65.4% relative to the control in Z and ZM aquaria, while 27.4% of initial concentration decreased in M aquarium, respectively. These results suggest that 1) this domestic freshwater filter-feeding bivalve plays a significant role in the control of cyanobacterial bloom (M. aeruginosa), and 2) the combination with zooplankton and mussel has a synergistic effect to diminish them, compared to the single treatment of zooplankton and mussel.

• Korean Journal of Food Science and Technology
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• v.45 no.1
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• pp.25-33
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• 2013

Clenbuterol and ractopamine, which are ${\beta}$-agonists, have been misused as a growth promoting agent in meat producing animals. Clenbuterol was banned for veterinary drug in Korea because of its problems regarding safety. Due to their adverse effects, such as cardiovascular and central nervous diseases on human health proper control and monitoring should be conducted. The existing analytical method of clenbuterol and ractopamine in the Food code was improved through our present study. The bovine muscle samples were subjected to enzymatic hydrolysis, extracted with ethyl acetate and defatted by hexane-methanol partitioning. A molecular imprinted polymer (MIP) solid phase extraction cartridge was used for clean-up and LC-MS/MS was operated in positive multiple reaction monitoring (MRM). Clenbuterol-$d_9$ and ractopamine-$d_3$ were used as an internal standard. The renewed method was validated according to the CODEX guideline. The limits of quantitation for clenbuterol and ractopamine were 0.2 and 0.5 ${\mu}g/kg$, respectively. The mean recoveries ranged in 104.2-113.5% for clenbuterol and in 107.6-118.1% for ractopamine. The improved method was able to save both time and expenses.

• Food Science of Animal Resources
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• v.30 no.3
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• pp.419-426
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• 2010

This study was conducted to investigate the effect of different castration ages on meat quality and sensory properties of Korean native black goats over 410 days. For the experiment, 32 heads of goat (eight heads/4 treatment) were subjected to either a control (5 month non-castration), T1 (7 month castration), T2 (5 month castration) or T3 (3 month castration). The total weight gain for Korean native black goats was highest in the T2 group after feeding for 410 days and the weight gain/day tended to be similar to the total weight gain. The total feeding amounts were lowest (410.82 kg) in T3; however, the feed intake ratio was 16.39 in T2, indicating that it had the best feed efficiency among groups. The cooking loss and drip loss of the Korean native black goats was highest in the control, being 35.53% and 2.08%, respectively (p<0.05), while the total cholesterol of the treatments was higher than that of the control (p<0.05). Moreover, the overall sensory evaluation of the treatment groups was low, indicating that there was more meat flavor when compared to the controls in terms of juiciness, tenderness, flavor, texture, black goat off-flavor and overall evaluation (p<0.05). T2 was found to have the best meat flavor upon sensory evaluation. Additionally, the meat color of the control showed the highest $L^*$ value and Hue value, while T3 showed the highest $a^*$ value (3.61) and T2 showed the highest $b^*$ value and Chroma. The composition of fatty acids was 53.76% oleic acid in T2, while the amounts of Mono-unsaturated fatty acid (MUFA) were highest in T1 and T2 (p<0.05). As a result, the MUFA/SFA ratios of T1 and T2 were higher than those of the control (p<0.05). In conclusion, it is most advantageous to castrate Korean native black goats at the age of 5 months for the best performance and meat quality.

• Journal of Gifted/Talented Education
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• v.20 no.3
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• pp.767-788
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• 2010

The purpose of this study was to examine emotional characteristics and to provide information about the special needs of counselling of science gifted in Korea. The subjects were 143 science gifted high school students in Busan that had been tested MBTI and MMPI-A. The distribution map of MBTI type was examined and Pearson's correlation, one-way ANOVA, multiple regression analysis were used to analyse the relation between MBTI and MMPI-A through SPSS 17.0 program. The results showed as follows: first, ENTP, INTP, ISTJ personality types and NT temperament type were the most frequently from the distribution map of MBTI type. Second, F1, F2, F, Hs, D, Pt, Sc and Si scales of MMPI-A were positively related to I preference of MBTI and K and Ma scales of MMPI-A were significantly related to E preference of MBTI from Pearson's correlation. Third, The score of IN group was significantly more high in F1, Hs, D, SC and Si scales of MMPI-A than other group in the relation between two combination preferences of MBTI and scale of MMPI-A. The following results were same; IS group in D, Si scales, EN group in Ma scale, IT group in Hs, D, Pt and S scales, IF group in VRIN, D and Si scales, ET in Ma scale, IJ group in D and Si, IP group in F1, F, Hs, D, Hy, Pt, Sc and Si scales, EJ and EP groups in Ma scale. Finally, I preference of MBTI by F1, F2, F, Hs, D, Pt, Sc and Si scales of MMPI-A, E preference of MBTI by Ma scale of MMPI-A, F preference of MBTI by K scale of MMPI-A and P preference of MBTI by Hy scale of MMPI-A were significantly predicted from multiple regression analysis. Limitations of the current study and the suggestions for further research were offered.

• Economic and Environmental Geology
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• v.38 no.1
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• pp.57-65
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• 2005

To investigate the characteristics of the volatile organic compounds (VOCs) concentration in the groundwater around Ulsan, Korea, 168 groundwaters, 12 stream waters, and 6 sewage waters were analyzed for 61 VOCs. Results showed that VOCs were not detected in stream waters and total VOCs concentration in 5 sewage waters was in the range of ND-22.3 ${\mu}$g/L. In 78 groundwater samples more than one VOCs were detected and VOCs concentration of the samples ranged from 0.1 ${\mu}$g/L to 387.1 ${\mu}$g/L. However, VOCs concentration of 66 samples out of 78 samples showed less than 10 ${\mu}$g/L and that of only 6 samples exceeded Korea drinking water limit (KDWL). 42 VOCs detected from the 168 groundwaters were 14 aromatic hydrocarbons out of 25, 27 chlorinated aliphatic hydrocarbons out of 35, and methyl tert-butyl ether (MTBE). Detection rate of each VOCs in the groundwaters was as follows: chloroform in 43 samples (25.6%), methylene chloride in 36 samples (21.4%), TCE in 26 samples (15.5%), 1,1-dichloroethane in 19 samples (1.3%), PCE in 16 samples (9.5%), cis-1,2-DCE in 15 samples (8.9%), and toluene in 14 samples (8.3%). Even though VOCs concentration in the groundwaters of the study area is still low, the city is expanding and the drinking water limit is becoming strict, and therefore continuous monitoring is necessary.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.1
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• pp.66-75
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• 2015

This study investigated eating behaviors (life-style, breakfast pattern, eating environment, snack pattern, and awareness of breakfast) by breakfast frequency (0~2 times, 3~6 times, and 7 times per week) of high school students (146 males and 165 females) in the Yongin region. The percentage of 'mother' as breakfast preparer increased with elevated breakfast frequency, whereas 'myself' was lower for females (P<0.001). Regarding reasons for skipping breakfast, 'getting more sleep' increased with elevated breakfast frequency, whereas 'loosing appetite' decreased in males (P<0.001). Regarding family reaction to skipping breakfast, 'advising' increased with elevated breakfast frequency in females (P<0.001). Skipping breakfast by eating snacks was higher in females (51.6%) than in males (35.6%), and skipping dinner was higher (53.4%) in females. Awareness of breakfast importance increased with elevated breakfast frequency in males (P<0.05) and females (P<0.001). Perception of correlation between health and breakfast was higher in females (54.8%) compared to males (43.9%), and the most important reason was 'energy supplement'. 'Eating now and will eat' increased with elevated breakfast frequency in males (P<0.001) and females (P<0.001), whereas sum of 'not eating now and will not eat' and 'eating now but will not eat' were 19.2% and 14.2% in males and females, respectively. Therefore, appropriate education programs emphasizing importance of eating breakfast and environmental improvement for regularly eating breakfast for high school students are highly required.

• Journal of dental hygiene science
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• v.12 no.6
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• pp.644-651
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• 2012

This study purports to measure the level of work friendship in dental clinic and examines the friendship's effect on the organizational effectiveness. Data were collected from workers who worked in dental clinic located in Seoul and Gyeonggi areas by self-administered questionnaires from early in October till lately in September, 2009 through direct interview and e-mail. Among 250 questionnaires, 240 responses were returned, and 17 copies with an inaccurate answer were excluded. Finally 223 responses were analyzed through SPSS program. The study revealed that the work friendship in dental clinic has enormous influence on job satisfaction, occupational commitment, intent to leave, stress etc. The results imply that the managers of the dental clinics need to create an organizational climate which emphasizes on a good relationship among members and have them take part in various committees or informal activities.

• Journal of Chitin and Chitosan
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• v.23 no.4
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• pp.244-255
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• 2018

Natural extract in liquid phase was adjusted to 0, 0.25, 0.5, 1, 2, and 4% concentration to check microbial changes and to measure 4, 8, $12^{\circ}C$ for refrigeration temperature. In the case of grapefruit extract, the microbial safety was maintained at all the concentrations at $4^{\circ}C$ storage, but the antimicrobial activity was maintained at $12^{\circ}C$ storage and at $8^{\circ}C$ and 21 days storage. In the case of grape seed extract, only the 4% of the culture at $8^{\circ}C$ satisfied the requirement of safety of food distribution for the last 21 days, and the safety criterion was satisfied only at 4% concentration at $12^{\circ}C$ for 18 days. Complex Scutellaria baicalensis extract showed the total number of microbial cells treated by concentration. It was confirmed that microbial flow safety was maintained at low temperature ($4^{\circ}C$). However, at $8^{\circ}C$ and $12^{\circ}C$, Exceeded the distribution limit. When polylysine was applied to brown rice cake, it showed activity in all groups except $4^{\circ}C$, but these properties were not observed at $8^{\circ}C$ and $12^{\circ}C$. At a concentration of 0.5% or more of chitosan, the growth of the microorganism is suppressed by the 21st day very stably, and a similar tendency is observed at 8 and $12^{\circ}C$, so that it may be an antimicrobial material that inhibits microorganisms. At the first day, the distribution standards for general bacterial counts were exceeded.Ethyl-pyruvate showed that microorganism safety was maintained at $4^{\circ}C$ and 1% concentration, and food safety was stable even at 2 or 4%. Glycine showed very good and stable distribution stability at $4^{\circ}C$. However, at $8^{\circ}C$ and $12^{\circ}C$, the shelf life of 14 days could not be maintained as with the addition of other antimicrobial active substances.

• FLOWER RESEARCH JOURNAL
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• v.19 no.1
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• pp.22-29
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• 2011

The experiment investigated effect of duration, temperature, and light condition during chilling treatment on growth and flowering of four Campanula species in a factorial experiment. Two parent species, Campanula punctata Lam. var. rubriflora Mak. and C. Punctata Lam., and their two $F_1$ hybrids, C. punctata Lam. ${\times}$ C. punctata Lam. var. rubriflora Mak. ('Jiknyeo') and C. punctata Lam. var. rubriflora Mak. ${\times}$ C. punctata Lam. ('Gyeonu'), were used. Plants were cultured in vitro for five weeks at $25^{\circ}C$ under about $75{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD before being chilled at 4 or $25^{\circ}C$ for 3, 6, or 9 weeks under a darkened or lighted (about $10{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD) condition. After chilling treatment, plants were transplanted to 10 cm pots filled with a commercial growing medium and were transferred to environment-controlled growth chambers and subsequently to a greenhouse to observe their reproductive growth. Growth of all species and flowering of a $F_1$ hybrid 'Jiknyeo' were affected by duration, temperature, and light condition during chilling treatment. The greatest growth and survival percentage were observed in C. punctata Lam. var. rubriflora Mak. The survival percentage was greater when plants were chilled in a lighted than darkened condition, whereas it decreased when plants were chilled more than six weeks in vitro. Among the four species tested, flowering was observed only in a $F_1$ hybrid 'Jiknyeo' with 62.5% flowering plants when it was chilled at $25^{\circ}C$ for three weeks under a lighted condition. Percent flowering plant was affected by duration, temperature, and light condition during chilling treatment. Three-week chilling at $4^{\circ}C$ under a darkened condition significantly reduced days to flowering. These results suggest that the low temperature requirement for flowering is not qualitative but quantitative in Campanula species. Further experiment with more number of plants is necessary to ascertain this conclusion.