• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.2
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• pp.351-373
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• 2019

The cold eddies around the Ulleung Basin in the East Sea were identified from satellite altimeter sea level data using the Winding-Angle method from 1993 to 2015. Among the cold eddies, the Dokdo Cold Eddies (DCEs), which were formed at the first meandering trough of the East Korea Warm Current (EKWC) and were pinched off to the southwest from the eastward flow, were classified and their migration patterns were analyzed. The vertical structures of water temperature, salinity, and flow velocity near the DCE center were also examined using numerical simulation and observation data provided by the Hybrid Coordinate Ocean Model and the National Institute of Fisheries Science, respectively. A total of 112 DCEs were generated for 23 years. Of these, 39 DCEs migrated westward and arrived off the east coast of Korea. The average travel distance was 250.9 km, the average lifespan was 93 days, and the average travel speed was 3.5 cm/s. The other 73 DCEs had moved to the east or had hovered around the generated location until they disappeared. At 50-100 m depth under the DCE, water temperature and salinity (T < $5^{\circ}C$, S < 34.1) were lower than those of ambient water and isotherms made a dome shape. Current faster than 10 cm/s circulates counterclockwise from the surface to 300 m depth at 38 km away from the center of DCE. After the EKWC separates from the coast, it flows eastward and starts to meander near Ulleungdo. The first trough of the meander in the east of Ulleungdo is pushed deep into the southwest and forms a cold eddy (DCE), which is shed from the meander in the south of Ulleungdo. While a DCE moves westward, it circumvents the Ulleung Warm Eddy (UWE) clockwise and follows U shape path toward the east coast of Korea. When the DCE arrives near the coast, the EKWC separates from the coast at the south of DCE and circumvents the DCE. As the DCE near the coast weakens and extinguishes about 30 days later after the arrival, the EKWC flows northward along the coast recovering its original path. The DCE steadily transports heat and salt from the north to the south, which helps to form a cold water region in the southwest of the Ulleung Basin and brings positive vorticity to change the separation latitude and path of the EKWC. Some of the DCEs moving to the west were merged into a coastal cold eddy to form a wide cold water region in the west of Ulleung Basin and to create a elongated anticlockwise circulation, which separated the UWE in the north from the EKWC in the south.

• Journal of Life Science
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• v.29 no.1
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• pp.60-68
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• 2019

Limonium tetragonum, an edible halophyte that grows on salt marshes in Korea, is thought to possess various health benefits (e.g., antioxidant, antitumor, and hepatoprotective). In the present study, different solvent partitioned subfractions, water ($H_2O$), buthanol (n-BuOH), 85% aqueous methanol (85% aq. MeOH), and hexane (n-hexane), from crude extract of L. tetragonum were tested for their ability to prevent adipogenesis in differentiating 3T3-L1 preadipocytes. The treatment of differentiating 3T3-L1 preadipocytes with L. tetragonum subfractions (LTFs) resulted in suppressed adipogenesis and reduced expression of adipogenesis-related transcription factors such as peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$), CCAATT/enhancer-binding protein alpha ($C/EBP{\alpha}$), and sterol regulatory element-binding protein 1c (SREBP-1c) at both mRNA and protein levels. In addition, the LTF treatment notably decreased the levels of phosphorylated p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) of the mitogen-activated protein kinase (MAPK) pathway in association with $PPAR{\gamma}$-linked adipogenesis. Among all the tested LTFs, $H_2O$ and n-hexane were the most effective in lowering lipid accumulation and regulating the adipocyte differentiation via $PPAR{\gamma}$ pathway. Taken together, the results indicated that the $H_2O$ and n-hexane LTFs contain bioactive compounds that may exhibit significant antiadipogenesis activity by downregulation of the $PPAR{\gamma}$ pathway and inactivation of the MAPK signal pathway in 3T3-L1 preadipocytes.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.2
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• pp.318-331
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• 2019

In this study, comparative analysis is performed on the long-term persisted warm eddies that were generated in 2003 (WE03) and in 2014 (WE14) over the East Sea using the HYCOM reanalysis data. The overshooting of the East Korea Warm Current (EKWC) was appeared during the formation period of those warm eddies. The warm eddies were produced in the shallow Korea Plateau region through the interaction of the EKWC and the sub-polar front. In the interior of the both warm eddies, a homogeneous water mass of about $13^{\circ}C$ and 34.1 psu were generated over the upper 150 m depth by the winter mixing. In 2004, the next year of the generation of the WE03, the amount of the inflow through the western channel of the Korea Strait was larger, while the inflow was lesser than its climatology during 2015 corresponding to the development period of the WE14. The above results suggest that the heat and salt are supplied in the warm eddies through the Tsushima Warm Current (TWC), however the amount of the inflow through the Korea Strait has negligible impact on the long-term persistency of the warm eddies. Both of the warm eddies were maintained more than 18 months near Ulleung island, while they have no common feature on the pathways. In the vicinity of the Ulleung basin, large and small eddies are continuously created due to the meandering of the EKWC. The long-term persisted warm eddies in the Ulleung Island seem to be the results of the interaction between the pre-existed eddies located south of the sub-polar front and fresh eddies induced by the meanderings of the EKWC. The conclusion is also in line with the fact that the long-term persisted warm eddies were not always created when the overshooting of the EKWC was appeared.

• Journal of Korea Society of Waste Management
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• v.34 no.2
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• pp.205-213
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• 2017

The current study was performed to investigate the effect of recycling coir substrates on the growth, fruit yield, and quality of strawberry plants. Analysis of physical properties revealed that the pH of a fresh coir substrate was 5.04 while those of substrates reused for one and two years were 5.20 and 5.33, respectively. The electrical conductivity (EC) of a new substrate was as high as $4.58dS{\cdot}m^{-1}$. This can cause salt stress after transplanting. The EC tended to decrease as the substrate was recycled, and the EC of a two-year recycled substrate was $1.48dS{\cdot}m^{-1}$. The fresh substrate had lower nitrogen and calcium concentrations, but higher phosphate, potassium, and sodium concentrations than the recycled coir substrate. The coir substrates recycled for one or two years maintained better chemical properties for plant growth than the fresh substrate. Strawberry growth varied depending on the number of years that the coir substrate was recycled. In general, strawberries grown in substrates that had been reused for two years did better than those grown in substrates that had been reused once or were fresh. Ninety days after transplanting, a plant grown in a substrate that had been reused for two years contained 25 leaves, which was 3.6 more than with a fresh substrate. In addition, the plants grown in a substrate that had been reused for two years exhibited larger leaf areas than those grown in other substrates. Coir substrates that had been reused for one year increased the number and area of leaves, but not as much as the substrate that had been reused for two years. One- and two-year reused coir substrates increased the weight of strawberries produced relative to the unused substrate, but the difference was not statistically significant. The plants grown in two-year reused substrates were longer and wider, as well. Also, the number of fruits per plant was higher when substrates were reused. Specifically, the number of fruits per plant was 28.7 with a two-year reused substrate, but only 22.2 with a fresh substrate. The fruit color indices (as represented by their Hunter L, a, b values) were not considerably affected by recycling of the coir substrate. The Hunter L value, which indicates the brightness of the fruit, did not change significantly when the substrate was recycled. Neither Hunter a (red) nor b (yellow) values were changed by recycling. In addition, there were no significant changes in the hardnesses, acidities, or soluble solid-acid ratios of fruits grown in recycled substrates. Thus, it is thought that recycling the coir substrate does not affect measures of fruit quality such as color, hardness, and sugar content. Overall, reuse of coir substrates from hydroponic culture as high-bed strawberry growth substrates would solve the problems of new substrate costs and the disposal of substrates that had been used once.

• Journal of Nutrition and Health
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• v.53 no.6
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• pp.676-687
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• 2020

Purpose: The purpose of this study was to investigate the differences in portion size of 11 types of foods that Korean adults frequently consume, based on the parameters of eating place, gender, and age using the Korea National Health and Nutrition Examination Survey (KNHANES) data. Methods: The dietary survey data from 2012-2016 KNHANES was used. A total of 19,779 subjects (8,034 male [40.6%], 11,745 female [59.4%]) were classified based on gender, three age groups (19-29 years old [15.7%], 30-49 years old [46.9%], 50-64 years old [37.4%]) and three eating places (home, institution, and restaurants/convenient stores etc.). Results: The portion sizes according to the eating places were calculated as per the median intake of Korean adults. Foods that showed the highest median intake in restaurants/convenience stores were boiled rice and kimchi stew. The median intake quantity of kimchi stew was the highest in restaurants/convenience stores in men across most age groups. Women in 30-49 years age group also consumed a lot of kimchi stew in restaurants/convenience stores. Men in the age groups 30-49 and 50-64 years consumed soybean paste stew the most in institutions compared to home and restaurants/convenient stores. Stir-fried pork was consumed the most at institutional meal places across all age groups. Conclusion: The portion sizes of kimchi stew and boiled rice were the highest in restaurants/convenience stores. As kimchi stew and soybean paste stew is high in sodium, the intake should be reduced in institutions and restaurants/convenience stores. Furthermore, it is necessary to reduce sodium intake through consumer nutrition education and the development of low-salt standard recipes for restaurants.

• Journal of agriculture & life science
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• v.53 no.1
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• pp.13-21
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• 2019

This study was carried out to acquire basic data for a long-term hydroponic culture through investigating water and inorganic ion uptake characteristics at different EC level of nutrient solution of three tomato varieties. Three different tomato varieties, the European type(cv. Daphnis), the Asian type(cv. Super Doterang) and cherry type(cv. Minichal), were used for the investigation. Also, the deep flow technique(DFT) was applied. The three different electrical conductivity(EC) level(1.0, 2.0, 3.0, and 4.0 dS·m-1) of hydroponic nutrient solution were used as variable. At a high EC level of nutrient solution, the leaf area and fresh weight decreased in the early stage, and its growth(plant height, leaf number, leaf area, fresh-weight) was poor with salt stress. Result showed that the higher the EC level of the nutrient solution, the lesser was water uptake. The water uptake was not significantly different from varieties in the first survey, but In the second survey, the 'Daphnis' did not show a significant decrease in water uptake in the EC level higher than 2.0 dS·m-1., on the other hand, 'Super Doterang' presented very low water uptake. At a low EC level, N, P, and K, were absorbed more than the concentration of the irrigation water, while Ca, Mg, S uptake were low. At a high EC level, almost ions absorbed less than 50% of the initial concentration of irrigation water. Thus, imbalance among ions was severe at low EC level compared to high EC level. 'Daphnis' was a variety that effectively utilize nutrients under nutrient stress, showing high absorption at low concentration condition and low absorption at high concentration condition. However, 'Daphnis' suffered most seriously by absorbing nutrients excessively.

• Journal of Life Science
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• v.32 no.7
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• pp.578-587
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• 2022

Korea, as the world's 7^th largest emitter of greenhouse gases, has raised the national greenhouse gas reduction target as international regulations have been strengthened. As it is possible to utilize coastal and marine ecosystems as important nature-based solutions (NbS) for implementing climate change mitigation or adaptation plans, the blue carbon ecosystem is now receiving attention. Blue carbon refers to carbon that is deposited and stored for a long period after carbon dioxide (CO₂) is absorbed as biomass by coastal ecosystems or oceanic ecosystems through photosynthesis. Currently, there are only three blue carbon ecosystems officially recognized by the Intergovernmental Panel on Climate Change (IPCC): mangroves, salt marshes, and seagrasses. However, the results of new research on the high CO₂ sequestration and storage capacity of various new blue carbon sinks, such as seaweeds, microalgae, coral reefs, and non-vegetated tidal flats, have been continuously reported to the academic community recently. The possibility of IPCC international accreditation is gradually increasing through scientific verification related to calculations. In this review, the current status and potential value of seaweeds, seagrass fields, and non-vegetated tidal flats, which are sources of blue carbon on the east coast, are discussed. This paper confirms that seaweed resources are the most effective NbS in the East Sea of Korea. In addition, we would like to suggest the direction of research and development (R&D) and utilization so that new blue carbon sinks can obtain international IPCC certification in the near future.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.287-298
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• 2022

This study evaluated the efficacy of chlorine dioxide (ClO₂) as an oxidant to reduce malodor emission from chicken feces. Two experiments were performed with the following four treatments in parallel: 1) fresh chicken feces with only distilled water added as a control, 2) a commercial germicide as a positive control, and 3) 2,000 or 4) 3,000 ppm of ClO₂ supplementation. Aluminum gas bags containing chicken feces sealed with a silicone plug were used in both experiments, and each treatment was tested in triplicate. In Experiment 1, 10 mL of each additive was added on the first day of incubation, and malodor emissions were then assessed after 10 days of incubation. In Experiment 2, 1 mL of each additive was added daily during a 14-day incubation period. At the end of the incubation, gas production, malodor-causing substances (H₂S and NH₃ gases), dry matter, pH, volatile fatty acids (VFAs), and microbial enumeration were analyzed. Supplementing ClO₂ at 2,000 and 3,000 ppm significantly reduced the pH and the ammonia-N, total VFA, H₂S, and ammonia gas concentrations in chicken feces compared with the control feces (P<0.05). Additionally, microbial analysis indicated that the number of coliform bacteria was decrease after ClO₂ treatment (P<0.05). In conclusion, ClO₂ at 2,000 and 3,000 ppm was effective at reducing malodor emission from chicken feces. However, further studies are warranted to examine the effects of ClO₂ at various concentrations and the effects on malodor emission from a poultry farm.

• Journal of Applied Biological Chemistry
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• v.65 no.3
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• pp.129-142
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• 2022

Ginseng sprouts, which can be eaten from leaves to roots, has the advantage of not having to use pesticides without being affected by the season by using smart farms. The optimal cultivation timing of sprout ginseng was checked and the nutritional content and antioxidant activity were compared and analyzed. The values of total fatty acids and total minerals were no significant changes during the growth periods. The contents of total amino acids were slightly decreased to 45 days and after increased to 65 days. When the growth period was 65 days, arginine had the highest content of 3309.11 mg/100 g. The total phenolic contents were high at 3.73 GAE mg/g on the 45 days, and the total flavonoid contents were also the highest at 9.04 RE mg/g on the 45 days. The contents of total ginsenoside was not noticeable for the growth periods (29.83 on 25 days→32.77 on 45 days→26.02 mg/g on 65 days). The ginsenoside Rg2 (0.62 mg/g), Re (8.69 mg/g), Rb1 (4.75 mg/g) and Rd (3.47 mg/g) had highest contents on 45 days during growth. The values of phenolic acids and flavonols were gradually increased to 45 days (338.6 and 1277.14 ㎍/g) and then decreased to 65 days. The major compounds of phenolic acids and flavonols were confirmed to benzoic acid (99.03-142.33 ㎍/g) and epigallocatechin (416.03-554.64 ㎍/g), respectively. The values of 2,2-diphenyl-1-picrylhydrazyl (44.27%), 2,4,6-azino-bis (3-ethylbenzothiazoline-6-sulphnoic acid) diammonium salt (75.16%), and hydroxyl (63.29%) radical scavenging activities and ferric reducing/antioxidant power (1.573) showed the highest activity on the 45 days as well as results of total phenolic and total flavonoid contents.

• Journal of Wetlands Research
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• v.24 no.3
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• pp.204-212
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• 2022

The LID technique began to be applied in Korea after 2009, and LID facilities are installed and operated for rainwater management in business districts such as the Ministry of Environment, the Ministry of Land, Infrastructure and Transport, and LH Corporation, public institutions, commercial land, housing, parks, and schools. However, looking at domestic cases, the application cases and operation periods are insufficient compared to those outside the country, so appropriate design standards and measures for operation and maintenance are insufficient. In particular, LID facilities constructed using LID techniques need to maintain the environment inside LID facilities because hydrological and environmental effects are expressed by material circulation and energy flow. The LID facility is designed with the treatment capacity planned for the water circulation target, and the proper maintenance, vegetation, and soil conditions are periodically identified, and the efficiency is maintained as much as possible. In other words, the soil created in LID is a very important design element because LID facilities are expected to have effects such as water pollution reduction, flood reduction, water resource acquisition, and temperature reduction while increasing water storage and penetration capacity through water circulation construction. In order to maintain and manage the functions of LID facilities accurately, the current state of the facilities and the cycle of replacement and maintenance should be accurately known through various quantitative data such as soil contamination, snow removal effects, and vegetation criteria. This study was conducted to investigate the current status of LID facilities installed in Korea from 2009 to 2020, and analyze soil changes through the continuity and current status of LID facilities applied over the past 10 years after collecting soil samples from the soil layer. Through analysis of Saturn, organic matter, hardness, water contents, pH, electrical conductivity, and salt, some vegetation-type LID facilities more than 5 to 7 years after construction showed results corresponding to the lower grade of landscape design. Facilities below the lower level can be recognized as a point of time when maintenance is necessary in a state that may cause problems in soil permeability and vegetation growth. Accordingly, it was found that LID facilities should be managed through soil replacement and replacement.