• Child Health Nursing Research
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• v.20 no.3
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• pp.159-167
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• 2014

Purpose: The purpose of this study was to investigate factors associated with sexual debut among Korean middle school students. Methods: From the database of the Eighth Korea Youth Risk Behavior Web-based Survey (KYRBS), the researchers selected 37,297 middle school students aged 12-15 years. Data were analyzed using $x^2$ test and multiple logistic regression with the SPSS WIN 18.0 program. Results: The proportion of middle school students who had a sexual debut was 2.1% of boys and 1.5% of girls. In multiple regression analysis, economic status, experience of part time work, smoking, drug use and depression were associated with an increased proportion of sexual intercourse for both boys and girls. Living with parents, drinking alcohol and suicidal ideation were associated with sexual debut for boys only. By contrast, formal sexual education was associated with a reduced risk of sexual debut. Conclusion: The results of this study show the factors associated with sexual debut among Korean middle school students. Gender-related interventions should be taken into consideration in school sexual education programmes, because of differences in related factors according to gender.

• Journal of Life Science
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• v.21 no.5
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• pp.631-646
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• 2011

Mesenchymal stem cells (MSC) are multipotent and can be isolated from diverse human tissues including bone marrow, fat, placenta, dental pulp, synovium, tonsil, and the thymus. They function as regulators of tissue homeostasis. Because of their various advantages such as plasticity, easy isolation and manipulation, chemotaxis to cancer, and immune regulatory function, MSCs have been considered to be a potent cell source for regenerative medicine, cancer treatment and other cell based therapy such as GVHD. However, relating to its supportive feature for surrounding cell and tissue, it has been frequently reported that MSCs accelerate tumor growth by modulating cancer microenvironment through promoting angiogenesis, secreting growth factors, and suppressing anti-tumorigenic immune reaction. Thus, clinical application of MSCs has been limited. To understand the underlying mechanism which modulates MSCs to function as tumor supportive cells, we co-cultured human adipose tissue derived mesenchymal stem cells (ASC) with cancer cell lines H460 and U87MG. Then, expression data of ASCs co-cultured with cancer cells and cultured alone were obtained via microarray. Comparative expression analysis was carried out using DAVID (Database for Annotation, Visualization and Integrated Discovery) and PANTHER (Protein ANalysis THrough Evolutionary Relationships) in divers aspects including biological process, molecular function, cellular component, protein class, disease, tissue expression, and signal pathway. We found that cancer cells alter the expression profile of MSCs to cancer associated fibroblast like cells by modulating its energy metabolism, stemness, cell structure components, and paracrine effect in a variety of levels. These findings will improve the clinical efficacy and safety of MSCs based cell therapy.

• Korean Journal of Environment and Ecology
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• v.33 no.6
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• pp.624-635
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• 2019

Bird strike accidents, a collision between aircraft and birds, have been increasing annually due to an increasing number of aircraft operating each year to meet heavier demand for air traffic. As such, many airports have conducted studies to assess and manage bird strike risks effectively by identifying and ranking bird species that can damage aircraft based on the bird strike records. This study was intended to investigate the bird species that were likely to threaten aircraft and compare and discuss the risk of each species estimated by the single-matrix and multi-matrix risk assessment models based on the Integrated Flight Information Service (IFIS) data collected in Gimpo, Gimhae and Jeju Airports in South Korea from 2005 to 2013. We found that there was a difference in the assessment results between the two models. The single-matrix model estimated 2 species and 6 taxa in Gimpo and Gimhae Airports and 2 species and 5 taxa in Jeju Airport to have the risk score above "high," whereas the multi-matrix model estimated 3 species and 5 taxa in Gimpo Airport, 4 species and 5 taxa in Gimhae Airport, and 2 species and 3 taxa in Jeju Airport to have the risk score above "very high." Although both models estimated the similar high-risk species in Gimpo and Gimhae Airports, there was a significant difference in Jeju Airport. Gimpo and Gimhae Airports are near the estuary of a river, which is an excellent habitat for large and heavy waterbirds. On the other hand, Jeju Airport is near the coast and the city center, and small and light bird species are mostly observed. Since collisions with such species have little effect on aircraft fuselage, the impact of common variables between the two models was small, and the additional variables caused a significant difference between the estimation by the two models.

• Journal of fish pathology
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• v.30 no.2
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• pp.89-96
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• 2017

The majority of freshwater ornamental fish are imported and distributed domestically, causing high risk of exposure to exotic pathogens and drug resistant bacteria in Korea. Aeromonas hydrophila is known as a common species of fresh water bacteria and opportunistic fish pathogen, as well as a species causing zoonotic infection. In this study, we isolated motile aeromonads from various imported freshwater ornamental fish and studied the characters of the isolates. Imported freshwater ornamental fish were purchased on day 1 after the fish were deposited in the aquarium. Bacteria were isolated from the liver, kidney and spleen of fish using 0.5% NaCl containing tryptic soy agar medium. Bacteria were grouped on the basis of their morphological characteristics. The colonies with clear zone on starch-ampicillin agar (SA agar) were tentatively identified as Aeromonas spp. Two hundred and twenty-six strains, about 70% of total isolates were assumed to be Aeromonas spp. Nine isolates were further identified based on the result of the API 20E test and PCR using primers specific for A. hydrophila 16S rRNA gene. The isolates were identified as A. hydrophila and the API 20E test showed differences in trisodium citrate, D-sucrose, D-melibiose, amygdalin and L-arabinose availability between the nine isolates and standard A. hydrophila. The susceptibilities of the isolated bacteria to 10 antibacterial agents were confirmed by the disk diffusion method. Isolated strains were found to be resistant to amoxicillin and ampicillin and sensitive to florfenicol. However, 7 isolates showed multiple drug resistances to erythromycin, oxytetracycline, nalidixic acid etc. Pathogenicity of the isolates was determined by the artificial challenge test on goldfish (Carassius auratus). Three isolates caused 60 ~ 80% mortality in goldfish within 5 days after the initiation of challenge. These results indicate that multiple drug resistant, highly pathogenic and exotic A. hydrophila can spread to domestic aquarium and the preventive treatment of fish before sale is necessary.

• The Journal of the Petrological Society of Korea
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• v.24 no.3
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• pp.165-180
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• 2015

Jurassic granite from Geochang was analysed with respect to the characteristics of the rock cleavage. The phases of distribution of microcracks were well evidenced from the enlarged photomicrographs(${\times}6.7$) of the thin section. In this study, the length - cumulative frequency diagrams were used for expressing the distribution characteristics of microcrack. The diagrams for the six directions were arranged in the magnitude of density(${\rho}$). These diagrams show an order of H2 < H1 < G2 < G1 < R2 < R1 from the related chart. Among six diagrams, the diagram for hardway 2(H2) occupies the lowermost region on the left. On the contrary, the diagram for rift 1(R1) occupies the uppermost region on the right. Curve patterns of the two diagrams change from uniform to exponential distribution type in accordance with the increased density. The overall distribution characteristics of the diagrams were well evidenced from the magnitude of the exponent(${\lambda}$) and length of line oa related to the exponential straight line. The magnitude of exponent governing the values of slope(${\theta}$) is inversely proportional to the values of microcrack parameters such as number(N), length(L) and density. On the contrary, length of line oa is directly proportional to the values of the above three parameters. Above microcrack parameters related to the order of arrangement of diagrams show an order of hardway(H1 + H2) < grain(G1 + G2) < rift(R1 + R2). The distribution characteristics of progressive variation are found among the six diagrams. The order of arrangement of the diagrams indicates a relative magnitude of the rock cleavage. Meanwhile, the parameters such as slope, exponent, density and length of line oa were arranged in an order of H2 < H1 < G2 < G1 < R2 < R1. The variation curves of a smooth quadratic function are shown from the related chart. From the correlation chart between density and the above parameters, a common regularity following power-law correlation function was derived. Finally, the analysis for the rock cleavage was conducted through the combination between the diagram and microcrack parameter. This type of combination contribute to the progressivity in evaluation for the rock cleavage.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.669-681
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• 2021

The content of major constituents and antioxidant activities of two lavers (Pyropia seriata, Pyropia dentata) selected through breeding at different regions (Jangsan-do, Amtae-do, Dali-do, Jin-do, Muan) were compared in this study. The mineral contents of both cultivars were in the following order: K>Na>Mg>Ca>Fe>Zn>Mn>Cu. The content of major fatty acids was as follows: eicosapentaenoic acid>palmitic acid>arachidonic acid>dihomo-ɣ-linolenic acid. Main constituents of total and free amino acids were as follows: alanine>glutamic acid>aspartic acid. In particular, the total amino acid content in P. dentata was higher than that in P. seriata and was the highest in the sample from Jangsan-do in January. In addition, in terms of total phenolic content, reducing power, and DPPH radical-scavenging activity of both samples collected in January and February, P. dentata showed better characteristics than P. seriata. This study may provide useful information for the selection of laver in high quality.

• Land and Housing Review
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• v.12 no.3
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• pp.11-26
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• 2021

With the increasing demand for office space, there have been questions on how office rent distribution produces a change in the urban spatial structure in Seoul. The purpose of this paper is to investigate a relative price gradient and to present a time-series model that can quantitatively explain the dynamic changes in the urban spatial structure. The analysis was dealt with office rent above 3,306 m² for the past 10 years from 1Q 2010 to 4Q 2019 within Seoul. A modified repeat sales model was employed. The main findings are briefly summarized as follows. First, according to the estimates of the office price gradient in the three major urban centers of Seoul, the CBD remained at a certain level with little change, while those in the GBD and the YBD continued to increase. This result reveals that the urban form of Seoul has shifted from monocentric to polycentric. This shows that the spatial distribution of companies has gradually accelerated decentralized concentration implying that the business networks have become significant. Second, contrary to small and medium-sized office buildings that have undertaken no change in the gradient, large office buildings have seen an increase in the gradient. The relative price gradients in small and medium-sized buildings were inversely proportional among the CBD, the GBD, and the YBD, implying their heterogeneous submarkets by office rent movements. Presumably, those differences in the submarkets were attributed to investment attraction, industrial competition, and the credit and preference of tenants. The findings are consistent with the hierarchical system identified in the Seoul 2030 Plan as well as the literature about Seoul's urban form. This research claims that the proposed method, based on the modified repeat sales model, is useful in understanding temporal dynamic changes. Moreover, the findings can provide implications for urban growth strategies under rapidly changing market conditions.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.39 no.4
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• pp.99-110
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• 2021

This study intends to examine the characteristics of the construction method of the urban water system in the historical cities of Korea, focusing on Gyeongju, Gyeongju, Goryeo, Hanyang, and Suwon Hwaseong, which were created as new towns in the late Joseon Dynasty. It examines the meaning of waterways in connection with the urban skeletal structure, focusing on the location of cities, roads, and arrangement of urban facilities, and analyzes the compositional form of the water system. We tried to derive the relationship with the structure. In particular, it can be seen that water and natural water systems act as key factors in determining the location of a city, and have a close relationship with the urban structure, urban development process, and urban structure. In addition to the symbolic meaning of water in harmony with the geographical concept, realistic demands in terms of water level and water retention are an important background. In order to respond to various demands related to water space, various planning and technical elements for managing water space were introduced in the process of city formation and development. The planning elements of the urban water system in the process of urban formation and development are summarized as follows through the analysis of the research site. First, in the process of building the urban water system in Gyeongju, Goryeo, Goryeo, Hanyang, and Hwaseong, Suwon, which were selected as the research destinations, the water system in consideration of drainage and disaster is common, but the water system construction method and usability are common. shows the difference. Second, water and natural water systems act as symbolic elements to secure the legitimacy of the city location, and as a key factor in determining the location of the city in harmony with the geographical concept and determining the left direction of the city. Third, the natural water system prior to the formation of a city works as a basis for determining the compositional form of the urban water system constructed in the process of urban formation and development in harmony with the topographical conditions. Fourth, the urban water system built on the basis of natural water systems is constructed by linking natural waterways and planned artificial waterways. Fifth, the urban water system is being built in a planned manner in consideration of the utility in connection with the urban structure, such as securing of urban land, arrangement of urban facilities and areas, composition of functional areas, and land division, in addition to the perspective of drainage system and flood control in consideration of disasters.

• Journal of Popular Narrative
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• v.26 no.3
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• pp.123-160
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• 2020

Manga develops by reflecting a change of society, reader's needs, and their thoughts and changes of tastes, sensitively. Shojo manga and Jyosei manga also do. We can find several kinds of meaningful changes in Japanese Jyosei manga in the 2010s. The works which represent preciousness of daily life, women's narrative and self-realization are gradually increasing. In addition, the works that deal with very touchy issues such as sex discrimination at work, sexual harassment begin to emerge. It has never been found in the manga of the former era. While this paper analyzes the social and cultural causes of these changes of the works that exclude romance and treat gender issues focusing on recent works, it examines changes of Japanese Jyosei manga in the 2010s and their meanings. I investigate the current trends of Japanese Jyosei manga in the 2010s through Umimachi Diary that represents a precious everyday life with woman-centered narrative, Metamorphose no engawa that deals with women's story from a new perspective, Good-bye My Miniskirt that tackles gender issues. Furthermore I intensively analyze how Nagi's Long Vacation and Darucyan, which win popularity from women in their 20s~30, represent lives and troubles of contemporary Japanese women. Nagi's Long Vacation represents the heroine's quest for a self throwing everything out. While Darucyan deals with self-realization, it forms of a bond of sympathy of readers by representing the heroine who suffers sexual harassment and inequal conditions very realistically. Nagi's Long Vacation and Darucyan have something in common with portraying troubles and self-realization of the working women in their 20s based on a indigenous reality to Japanese society very realistically. However they are unusual in that it is different from the manga of the former era in dealing with heroine's troubles and their solutions. The most distinctive changes of Jyosei manga since 2010 are that real issues surfaced with social changes. In addition, these social contradictions result from irrational discriminations and old customs of Japanese society for a long time. Manga reflects subtly the portraits of the times, their images of women, and their values. These changes of Jyosei manga also show the concerns of readers at that time, and it means that women began to be aware of the issues.

• Journal of The Korean Association For Science Education
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• v.43 no.1
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• pp.49-57
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• 2023

The purpose of this study is to analyze the school biology curriculum of the Royal Society of Biology (RSB) for school biology education in the United Kingdom (UK), and to examine the implications for Korean school biology education. The RSB school biology curriculum consists of three dimensions (the practices of biology, the concepts of biology, and the application of biology) and seven big questions. The contents of RSB school biology curriculum are structured according to age, 5-11, 11-16, and 16-19. The practices of biology of the UK RSB school biology curriculum emphasize biology activities should be linked to other communities and communicated and shared through evidence-based discussions. The concepts of biology dimension of the UK RSB school biology curriculum systematized the contents to be detailed considering school-level and ages with 5-7, 7-11, 11-14, 14-16, and 16-19 years old. The UK RSB biology curriculum is composed of human health, biological structure and function, biological growth and reproduction, and biological coexistence, showing a significant difference from Korean national curriculum when comparing the content elements with the core concepts of biology. In terms of the application of biology of the RSB school biology curriculum, three themes were commonly applied to all students, regardless of school level or age, such as development of application methods to promote health and environmental welfare, evaluation of the impact and application of biology knowledge. However, the content elements of the three themes were systematized according to the ages of 5-11, 11-16, and 16-19 years old. It is necessary to reorganize the contents of biology curriculum in Korea by referring to the content system of the UK RSB biology curriculum and to research ways to strengthen connectivity according to age or school level as well as dimensions and big questions.