• Development and Reproduction
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• v.12 no.3
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• pp.251-259
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• 2008

The plasticizer di(2-ethylhexyl)phthalate(DEHP) is one of the most well known endocrine disrupting chemicals (EDCs) because of its strong anti-androgenic effects on the reproductive and developmental process in male rodents and human. The present study was performed to examine whether prepubertal exposure to DEHP can make any alteration during the maturation of accessory sex organs in male rats. As a result, there was no significant change in body weights, serum T levels and tissue weights except of seminal vesicle and ventral prostate in DEHP-treated animals compared to vehicle-treated ones. The seminal vesicle weights in high-dose group (200 mg/kg) were significantly lower than those from the control group (p<0.05), and ventral prostate weights were significantly lower than those from the control group (p<0.05) in both low-dose (20 mg/kg) and high-dose group. Histological studies revealed that the seminal vesicles from DEHP-treated groups showed reduced areas of mucosal folds. Pseudostratified columnar epithelia were observed in the ventral prostates of DEHP-treated samples while cuboidal epithelia were found in the control group. The transcriptional activities of ER-$\alpha$ in seminal vesicle from high-dose group (p<0.05) were significantly higher than those from the control group, and ER-$\beta$ expression was significantly decreased in low-dose group (p<0.05) compared to the control. In ventral prostate, ER-$\beta$ mRNA levels from low-dose group (p<0.05) were significantly lower than those from the control group, and significantly increased in high-dose group (p<0.01). AR expressions, however, were not significantly different in all experimental groups of both seminal vesicle and ventral prostate. In conclusion, the present study demonstrated that (i) adverse effect (s) of DEHP on sexual maturation during prepubertal period could be limited, (ii) seminal vesicle and prostate gland were sensitive targets to DEHP in prepubertal rats and (iii) the deleterious effects of DEHP might be mediated through ER-associated mechanism.

• Economic and Environmental Geology
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• v.56 no.4
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• pp.435-445
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• 2023

A delta is a depositional landform that is formed when sediment transported by a river is deposited in a relatively low-energy environment, such as a lake, sea, or a main channel. Among these, a delta formed at the confluence of rivers has a great importance in river management and research because it has a significant impact on the hydraulic and sedimentological characteristics of the river. Recently, the equilibrium state of the confluence area has been disrupted by large-scale dredging and construction of levees in the Nakdong River. However, due to the natural recovery of the river, the confluence area is returning to its pre-dredging natural state through ongoing sedimentation. The time-series data show that the confluence delta has been steadily growing since the dredging, but once it reaches a certain size, it repeats growth and retreat, and the overall size does not change significantly. In this study, we developed a model to explain the sedimentation-erosion processes in the confluence area based on the assumption that the confluence delta reaches a dynamic equilibrium. The model is based on two fundamental principles: sedimentation due to supply from the tributary and erosion due to the main channel. The erosion coefficient that represents the Nakdong River confluence areas, was obtained using data from the tributaries of the Nakdong River. Sensitivity analyses were conducted using the developed model to understand how the confluence delta responds to changes in the sediment and water discharges of the tributary and the main channel, respectively. We then used annual average discharge of the Nakdong River's tributaries to predict the dynamic equilibrium positions of the confluence deltas. Finally, we conducted a simulation experiment on the development of the Gamcheon-Nakdong River delta using recorded daily discharge. The results showed that even though it is a simple model, it accurately predicted the dynamic equilibrium positions of the confluence deltas in the Nakdong River, including the areas where the delta had not formed, and those where the delta had already formed and predicted the trend of the response of the Gamcheon-Nakdong River delta. However, the actual retreat in the Gamcheon-Nakdong River delta was not captured fully due to errors and limitations in the simplification process. The insights through this study provide basic information on the sediment supply of the Nakdong River through the confluence areas, which can be implemented as a basic model for river maintenance and management.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.6
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• pp.70-83
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• 2022

This study aims to select evaluation items that can be used in planning park creation to evaluate the proposal to solve the environmental and social problems in promoting private-initiated park development projects. To this end, evaluation items that can consider various aspects of the development project were selected, and the indicators' validity and appropriateness were carried out through an expert Focus Group Interview (FGI). Firstly, an expert FGI was performed for six major categories and 50 evaluation items derived from literature reviews and brainstorming. As a result, five major and 27 middle category items were selected. Based on the derived major and middle classification items, 95 detailed items were selected. Secondly, 55 sub-items were derived through a suitability questionnaire. As a result of the suitability survey, the average scores of the subcategories for the major categories of natural environment, function of parks, and use of land were relatively high. The average scores for environmental index items such as ecology/vegetation, topography and slope, landscape, park service, wildlife, wide-area ecosystem, and park items were high in the middle classification. The average score of indicators in the natural environment was relatively high, and the average score in the function of parks also soared. In the environmental impact assessment, the occurrence of plan change issues, including the reappraisal of the location, led to unclear detailed evaluation factors for the faithfulness of the plan and the appropriateness of the plan direction. This study is significant in that it is a study on the selection of evaluation items that can minimize the problem of plan alteration and achieve objective evaluation when promoting development projects. This study could be used to forward development projects in the future and evaluate long-term unexecuted urban parks.

• Journal of Korea Water Resources Association
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• v.56 no.4
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• pp.261-272
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• 2023

In recent years, natural disasters such as heavy rainfall and typhoons have occurred more frequently, and their severity has increased due to climate change. The Korea Meteorological Administration (KMA) currently uses the same criteria for all regions in Korea for watch and warning based on the maximum cumulative rainfall with durations of 3-hour and 12-hour to reduce damage. However, KMA's criteria do not consider the regional characteristics of damages caused by heavy rainfall and typhoon events. In this regard, it is necessary to develop new criteria considering regional characteristics of damage and cumulative rainfalls in durations, establishing four stages: blue, yellow, orange, and red. A classification model, called DSCM (Disaster Severity Classification Model), for the four-stage disaster severity was developed using four machine learning models (Decision Tree, Support Vector Machine, Random Forest, and XGBoost). This study applied DSCM to local governments of Seoul, Incheon, and Gyeonggi Province province. To develop DSCM, we used data on rainfall, cumulative rainfall, maximum rainfalls for durations of 3-hour and 12-hour, and antecedent rainfall as independent variables, and a 4-class damage scale for heavy rain damage and typhoon damage for each local government as dependent variables. As a result, the Decision Tree model had the highest accuracy with an F1-Score of 0.56. We believe that this developed DSCM can help identify disaster risk at each stage and contribute to reducing damage through efficient disaster management for local governments based on specific events.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.2
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• pp.147-157
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• 2023

Centella asiatica extract is widely used as a raw material for cosmetics due to its various effects, but it is difficult to expect penetration into the skin due to its high molecular weight and low solubility. In order to solve these problems, lipid-based liposomes of various types were developed to increase skin absorption. Therefore, in this study, we tried to increase the skin absorption rate by preparing transfersomes using surfactants as edge activators in existing liposomes. Liposome and transfersomes containing Span 80 and Tween 20, 60, 80, and 85, respectively, were prepared using a high-pressure homogenizer, and we evaluated the particle size, polydispersity index, zeta potential, and skin absorption rate. As a result, there was almost no change in the physical properties of particle size, polydispersity index and zeta potential from 25 ℃ to 60 d, and the particle size of transfersomes containing Tween 20, 60, and 80 increased after 60 d at 45 ℃. Madecassoside, main substances of the Centella asiatica extract was used as an standard and madecassoside was measured and calculated when measuring the skin absorption rate using Franz diffusion cells. As a result, formulations containing Tween 20 were the most, whereas formulations containing Span 80 were the least. According to the skin absorption coefficient (Kp) value, all formulations showed 'very fast', and the absorption rate was similar or greater than that of liposomes, except for formulations containing Span 80. Through this, it was confirmed that the larger the HLB value of the nonionic surfactant, the smaller the particle size of the transfersome, and the increased skin absorption rate due to the increased flexibility of the vesicle membrane. Through this study, transfersome using surfactant as an edge activator can be expected to solve local skin problems not only as a cosmetic raw material or product, but also by increasing skin absorption.

• Journal of Nutrition and Health
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• v.56 no.6
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• pp.667-682
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• 2023

Purpose: This study aimed to investigate the changes in health behavior, mental health, and nutritional status of Korean adolescents before and after the coronavirus disease 2019 (COVID-19) pandemic outbreak. Methods: A total of 800 adolescents (12~18 years old) who participated in the 2019-2020 Korea National Health and Nutrition Examination Survey (KNHANES) were included as study subjects and divided into four groups (204 middle school boys, 172 middle school girls, 219 high school boys, and 205 high school girls). The 2019 and 2020 KNHANES data were classified into data collected before and after the COVID-19 outbreak, respectively. Results: After the COVID-19 pandemic outbreak, middle school boys showed an increased tendency toward becoming overweight and obese, with significantly increased levels of diastolic blood pressure and insulin. While there was no major change in the subjective health status among adolescents, the high school boys showed a significantly decreased physical activity after COVID-19 outbreak. Moreover, the proportion of middle school students feeling a little stressed significantly increased after the COVID-19 outbreak. The rate of skipping breakfast significantly increased in middle school girls, but the rate of having lunch with companions significantly increased among all adolescents after the COVID-19 outbreak. However, the intake of milk, vegetables, fruits, seaweeds, and pulses significantly decreased, although the intake of sugars, beverages, and seasonings significantly decreased as well, during this period. These changes may lead to an increased proportion of adolescents with insufficient intake of nutrients, including potassium, vitamin C, and riboflavin. Conclusion: These results highlight the impact of COVID-19 on comprehensive changes in physical and mental health status, lifestyle behavior, and nutritional status in adolescents, suggesting the need for targeted prevention and intervention for physical and mental well-being during the pandemic.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.3
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• pp.147-158
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• 2007

To clarify the bloom pattern and species succession in phytoplankton community, the population dynamics with the determination of physico-chemical factors have been studies in Masan Bay, the south sea of Korea, for the periods November 2003-October 2004. Concentration of $NH_4-N$ was always higher than that of $NO_3-N$, which was similar level as compared to other costal areas. $PO_4-P$ concentration was lower than those in other coastal areas but similar to oligotrophic environments. Thus, phosphate seems the limiting nutrient rather than nitrogen. $SiO_2-Si$ concentration was also low as compared to other costal areas. Si:P ratio was low from autumn to winter, suggesting silicate and/or phosphate limitation during this period. The cell density of phytoplankton was high in winter 2003 and early autumn 2004. The carbon biomass was high in winter 2003 and summer 2004. And chlorophyll-a concentration was high in late autumn 2003 and summer 2004. Among 78 species of phytoplankton found in the bay during the investigated period, dominant species were two diatoms of Cylindrotheca closterium, Skeletonema costatum, and three dinoflagellates of Heterocapsa triquetra, Prorocentrum minimum, P. triestinum, and one raphidophyte of Heterosigma akashiwo. P. minimum dominated from late autumn to winter, but it was replaced by H. triquetra in late winter. P. triestinum dominated from late spring to early summer. Simultaneously, H. akashiwo cell density steadily increased, and it became dominant with C. closterium in late summer. With decreasing of H. akashiwo and C. closterium, S. costatum became the most dominant species in autumn. The canonical analyses showed that total phytoplankton cell density related to diatom cell density and it was affected by temperature, and concentrations of $NO_3-N\;and\;PO_4-P$. The carbon bio-mass and $chlorophyll-{\alpha}$ concentration related to diatom- and dinoflagellate cell densities and these were affected by flagellate cell density, salinity, and concentrations of $SiO_2-Si\;and\;PO_4-P$. Last six years monitoring data in Masan city obtained from Korean Meteorological Agency indicates gradual increase in air temperature. And the precipitation decreased especially in spring season. The winter bloom found in 2003 may be caused by the increase in the temperature and this bloom subsequently induced the nutrients depletion, which continued until next spring probably due to no precipitation. Therefore, the spring bloom, which had been usually observed in the bay, might disappear in 2004.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.1
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• pp.35-45
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• 2020

This study focused on the park as a space to support the behavior of urban citizens in modern society. Modern city parks are not spaces that play a specific role but are used by many people, so their function and meaning may change depending on the user's behavior. In addition, current online data may determine the selection of parks to visit or the usage of parks. Therefore, this study analyzed the change of behavior in Yeouido Park, Yeouido Hangang Park, and Yangjae Citizen's Forest from 2000 to 2018 by utilizing a time series analysis. The analysis method used Big Data techniques such as text mining and social network analysis. The summary of the study is as follows. The usage behavior of Yeouido Park has changed over time to "Ride" (Dynamic Behavior) for the first period (I), "Take" (Information Communication Service Behavior) for the second period (II), "See" (Communicative Behavior) for the third period (III), and "Eat" (Energy Source Behavior) for the fourth period (IV). In the case of Yangjae Citizens' Forest, the usage behavior has changed over time to "Walk" (Dynamic Behavior) for the first, second, and third periods (I), (II), (III) and "Play" (Dynamic Behavior) for the fourth period (IV). Looking at the factors affecting behavior, Yeouido Park was had various factors related to sports, leisure, culture, art, and spare time compared to Yangjae Citizens' Forest. The differences in Yangjae Citizens' Forest that affected its main usage behavior were various elements of natural resources. Second, the behavior of the target areas was found to be focused on certain main behaviors over time and played a role in selecting or limiting future behaviors. These results indicate that the space and facilities of the target areas had not been utilized evenly, as various behaviors have not occurred, however, a certain main behavior has appeared in the target areas. This study has great significance in that it analyzes the usage of urban parks using Big Data techniques, and determined that urban parks are transformed into play spaces where consumption progressed beyond the role of rest and walking. The behavior occurring in modern urban parks is changing in quantity and content. Therefore, through various types of discussions based on the results of the behavior collected through Big Data, we can better understand how citizens are using city parks. This study found that the behavior associated with static behavior in both parks had a great impact on other behaviors.

• Cartoon and Animation Studies
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• s.37
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• pp.197-219
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• 2014

, one of the Disney's animations, hit the 10 million audience mark for the first time in the history of animations released in Korea. not only raised the fever with its theme song, 'Let it go', as well as Elsa, Anna, and Olaf's character products but caused sensations in many ways. If so, we need to think about what kind of meaning did create in Korea to be so sensational. This study examines the value that Frozen intended to deliver and the meaning it generated by using Greimas actant model and semiotic square. From the actant model analysis on Anna and Elsa from , it was identified that Anna desired to recover her relationship with Elsa and to take summer back in Arendelle. Her desires can be interpreted as her love toward Elsa and people in Arendelle. Meanwhile, Elsa always desired freedom although she confined herself because of her ability to freeze. In other words, Elsa desired to free herself from her freezing ability by finding out how to control her ability. Such desires of Anna and Elsa were achieved by their actions of true love, and the solution of all the conflicts in was an action of true love. From the semiotic square analysis on the meaning of , it was found out that created past-oriented value with which characters tried to change their abnormal lives of the present into their normal lives of the past. The characters tried to change their present lives where freezing winter comes in the middle of summer, communication between the sisters is cut off, and people try to take advantage of the abnormal state deliberately, into the past when the sisters had a good relationship and the natural season of summer in Arendelle. The past-oriented value that tried to tell us is similar to our reality. In our reality with a lot of unbelievable news and unstable circumstances, we desire to go back to the past when we were filled with affection and hope even though our lives were tough and difficult. This sentiment must have contributed to the huge success of in Korea.

• Journal of Nutrition and Health
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• v.53 no.2
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• pp.121-128
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• 2020

Purpose: The Rubus coreanus fruit (RF) is an important traditional medicinal herb having antioxidant, anti-inflammatory, and immunoregulatory properties. These activities are known to change dramatically, depending on maturity of the RF. It is presumed that change of functional components, such as flavonoids, tannins, phenolic acids, triterpenoids and organic acids in RF, affect the various bioactivities. This study aimed to confirm changes in the anti-melanogenic effects of RF based on maturity, and to identify the bioactive compounds responsible. Methods: The cell viability of mature RF (MRF) and immature RF (IRF) extracts was investigated using B16F10 cells. To compare the anti-melanogenic effect of MRF and IRF extracts, we first assessed the melanin content. High-performance liquid chromatography analysis was performed to evaluate changes in the level of ellagic acid according to maturity of the RF. In addition, tyrosinase inhibitory activity of both extracts was examined. Results: MRF and IRF extracts (50-200 ㎍/mL) do not affect the cell viability of B16F10 melanoma cells. IRF extract more effectively inhibited melanin synthesis than MRF extract. The content of ellagic acid in IRF extract was higher than that obtained in MRF extract. Furthermore, greater inhibition of tyrosinase activity was observed after exposure to IRF extract than MRF extract. A positive correlation was determined between ellagic acid content and tyrosinase inhibitory activity, and a negative correlation was obtained between ellagic acid content and melanin content. Taken together, our results indicate that ellagic acid is one of the major bioactive compounds of RF that imparts a whitening effect. Conclusion: Our results indicate that ellagic acid in MRF and IRF extracts affect the anti-melanogenesis effect through inhibition of tyrosinase activity. Therefore, the ellagic acid rich IRF has greater potential for application as a natural and functional cosmetic material.