• Restorative Dentistry and Endodontics
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• v.35 no.6
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• pp.453-460
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• 2010

Objectives: To evaluate the accuracy and consistency of two different apex locators at both the Apex and 0.5 marks. Materials and Methods: Twenty-six root canals was scheduled for extraction for periodontal or prosthodontic reasons. Thirteen canals were measured using Root ZX and the rest by i-ROOT. The root canal length was measured both the at 0.5 mark and the Apex mark. The file was then fixed to the toot, and the distance from the file tip to the major foramen of each canal was measured after removing the root dentin under the microscope so that the major foramen and the file tip were seen. Results: 1. When the Apex mark was used, 100% of both the Root ZX and i-ROOT groups were within 0.5 mm of the major foramen. 2. When 0.5 mark was used, 100% of the Root ZX group and 77% of the i-ROOT group were within 0.5 mm of the major foramen. 3. In terms of standard deviation and quartile value, the Apex mark was more consistent than 0.5 mark in the Root ZX group, and 0.5 mark was more consistent in the i-ROOT group, but there was no statistically significant difference when compared with t-test. 4. The root canal length difference between the Apex mark and 0.5 mark was 0.22 mm and 0.46 mm in the Root ZX and i-ROOT groups, respectively. Conclusions: In this study, the Apex mark was the more consistent mark. Therefore, it is recommended to subtract 0.5 mm, which is the average length between the apex and apical constriction, from the root canal length at the Apex mark to obtain the working length clinically.

• Restorative Dentistry and Endodontics
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• v.36 no.1
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• pp.26-36
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• 2011

Objectives: In the present study, three kinds of tissues cells (pulp, gingiva, and periodontal ligament) were investigated if those cells express MMP and TIMP when they were stimulated with neuropeptides (substance P, CGRP) or proinflammatory cytokine, TNF-$\alpha$. Materials and Methods: The cells cultured from human dental pulp (PF), gingiva (GF) and periodontal ligament were (PDLF) stimulated with Mock, SP, TNF-$\alpha$, and CGRP for 24 hrs and 48 hrs. for an RNase protection assay and Enzyme Linked Immunosorbent Assay. Cells (PF, GF and PDLF) seeded in 100 mm culture dish were stimulated with SP ($10^{-5}$, $10^{-8}\;M$) or only with medium (Mock stimulation) for 4hrs and for 24 hrs for RNase Protection Assay, and they were stimulated with CGRP ($10^{-5}\;M$) and TNF-$\alpha$(2 ng/mL) for 24 hrs and with various concentraion of TNF-$\alpha$(2, 10, and 100 ng/mL) for Rnase Protection Assay with a human MMP-1 probe set including MMP 1, 2, 8, 7, 8, 9, 12, and TIMP 2, 3. In addition, cells (PF, GF and PDLF) were stimulated with Mock and various concentraion of TNF-$\alpha$(2, 10, and 100 ng/mL) for 24 hrs and with TNF-$\alpha$(10 ng/mL) for 48 hrs, and the supernatents from the cells were collected for Enzyme Linked Immunosorbent Assay (ELISA) for MMP-1 and MMP-13. Results: The expression of MMPs in PF, GF, PDLF after stimulation with SP and CGRP were not changed compared with Mock stimulation for 4 hrs and 24 hrs. The expression of MMP-1, -12, -13 24 hrs after stimulation with TNF-$\alpha$ were upregulated, however the expression of TIMP-3 in PF, GF, PDLF after stimulation with TNF-$\alpha$ were downregulated. TNF-$\alpha$(2 ng/mL, 10 ng/mL, 100 ng/mL) increased MMP-1 and MMP-12 expression in PF dose dependently for 24 hrs. Conclusions: TNF-$\alpha$ in the area of inflammation may play an important role in regulating the remodeling of dentin, cementum, and alveolar bone.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.7
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• pp.866-873
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• 2006

The purpose of this study was to evaluate the current dietary habits, health related behaviors, nutrition knowledge and body indices, and to investigate the changes in nutrition knowledge for designing and monitoring nutrition education program among preschool children. The subjects were 1,200 preschool children, aged $4{\sim}6$ years. A measurement of the height and weight was conducted. The general home environment, the dietary habit of children and nutrition knowledge were collected using a questionnaire that included information about family income, parent's education and occupations. Using the PIBW, 14.6% of the preschool children were under weight, 54.4% were normal, and 31.0% were overweight or obese. We regarded to food habit score, the highest score was in the regularity of breakfast, while the lowest score was in consumption of yellow-green vegetables such as spinach and carrots. Result in food behavior showed that 69.1% of preschool children had a unbalanced diet, and their favorite snack was fast food like pizza and hamburger then followed soft drink and fried foods (chicken of potato). After nutrition education, there was somewhat improvement in the nutrition knowledge score of preschool children from $7.7{\pm}1.7$ point to $8.9{\pm}1.5$ point. These results suggest that nutrition education help preschool children change their nutrition knowledge. Therefore, it would be needed that new appropriate nutrition education to improve dietary habits and health status.

• Journal of Korean Society of Forest Science
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• v.78 no.2
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• pp.103-118
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• 1989

The occurrence of witches' broom in Ligustrum ovalifolium was first noticed in Korea by author in 1984. The present study was carried out with particular emphasis on the symptomatology, etiology, transmission of the disease and antibiotic treatments. The infected tissue was observed by the fluorescence and electron microscopy and its biochemical characteristics were compared with healthy one by electrophoresis. The results are summarized as follows : 1. symptoms of the infected trees were characterized by the dwarfing of the organs, yellowing and brooming of the foliage. 2. The observation by the trans electron microscopy on the witches' broom of L. ovalifolium revealed the occurrence of numerous mycoplasma-like organisms(MLOs) in the phloem tissue cells of the midribs of infected leaves. 3. The MLOs were surrounded by a single unit membrane, and they appeared to be multiplied by binary fission. 4. The presence of crystals unidentified in the phloem parenchyma cells was noticed by electron rnicroscopy, 5. The disease was able to be transmitted by budding, crown, and greenwood graftings to L. ovalifolium, L. obtusifolium, L, japonicum and also transmitted, even when the stocks and scions were not completely grafted. 6. Insect transmission on L. ovalifolium and L, obtzrsifolium was carried by Hishimonus sellatus. 7. The infected roots dipped in the 1,000 ppm of teracyclin solution was only temporarily effective in controlling the disease. 8. Infected plant with MLOs showed specific fluorescent reactions in phloems with DAPI stain. 9. The protein and peroxidase separated by electrophoresis showed strikingly distinctive difference between the healthy and diseased leaves.

• Journal of Legislation Research
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• no.53
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• pp.593-631
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• 2017

Like the technological competition of each country around commercialization of Autonomous Vehicles(the rest is 'AV'), legalizations are also in a competition. However, in the midst of this competition, the Ethik-Kommission Automatisiertes und vernetztes Fahren of Germany has recently introduced 20 guidelines. This guideline is expected to serve as a milestone for future AV legislations. In this paper, I have formulated a new legislative proposal that will incorporate the main content presented by the Ethik-Kommission. The structure is largely divided into general rules of purpose and definition, chapter on types of AV and safety standards, registration and inspection, maintenance, licenses for AV, driver's obligations, insurance and accident responsibilities, roads and facilities, traffic system, and chapter on penalties. The commercialization of AV in Korea seems to be in a distant future, and it is possible to pretend that it is not necessary to prepare legal systems. But considering our reality, leading legislation may be necessary. In this paper, I have prepared individual legislative proposals based on the essential matters based on the criminal responsibility in case of AV car accidents. To assure the safety of AV, AV and mode of operation were defined for more clear interpretation and application of law, and basic safety standards for AV were presented. In addition, the obligation of insurance and the liability for damages were defined, and the possibility of immunity from the criminal responsibility was examined. Furthermore, I have examined the penalties for penalties such as hacking in order to secure the effectiveness of the Act. Based on these discussions, I have attempted the 'Autonomous Vehicles Act', which aims to provide a basis for new discussions to be held on the basis of various academic fields related to the operation of AV and related industries in the future. Although there may be a sense of unurgency in time, the automobile industry needs time to prepare for the regulation of the AV ahead of time. And a process of public debate is also needed for the ecosystem of healthy AV industry.

• Korean Security Journal
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• no.57
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• pp.177-203
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• 2018

Police Assigned to Special Guard Act was legislated in 1962 to solve issues regarding the protection of various staple industrial installations, and in 2001, the Security Services Industry Act was revised to establish an effective security system for important national facilities. Thereby the Special Guards System was instituted. The current law has two parts, with the Police Assigned to Special Guard System and Special Guards System, and many scholars have actively discussed the appropriateness of the integration of both systems to solve problems caused by a bimodal system. However, in spite of these discussions taking place in the academic world, the idea of unification lost its power when the guarantee of status regulation was established for the police assigned to special guard. Strictly speaking, police assigned to special guard is a self-guard, and a special guard is a contractual guard. So, both of them have pros and cons. Thus, it would be desirable to give a legal, constitutional guarantee for both systems by strengthening each of them and making up for the weakness of each of them rather than trying to unify police assigned to special guard and special guard. To begin this process, we need to revise unreasonable legal provisions of Security Services Industry Act and Police Assigned to Special Guard Act as below. First, since the actual responsibilities of special guards and police assigned to special guard duty are the same, we need to make the facilities which they use equal. Second, legal provisions need to be revised so that a special guard may perform the duties of a police officer, according to the Act on the Performance of Duties by Police Officers, within the facility that needs to be secured in order to prevent any vacancy in the guarding of an important national facility. Third, disqualifications for the special guards need to be revised to be the same as the disqualifications for the police assigned to special guard duty. Fourth, it is reasonable to unify the training institution for special guards and for police assigned to special guard duty, and it should be the training institution for police. On-the-job education for a security guard needs to be altered to more than 4 hours every month just like the one for police assigned to special guard duty. Fifth, for a special guard, it is not right to limit the conditions in their using weapons to 'use of weapon or explosives' only. If one possesses 'dangerous objects such as weapon, deadly weapon, and so on' and resists, a special guard should be able to use their weapon against that person. Thus, this legal provision should be revised. Sixth, penalty, range of fines, and so on for police assigned to special guard duty need to be revised to be the same as the ones for a special guard. If we revise these legal provisions, we can correct the unreasonable parts of Security Services Industry Act and Police Assigned to Special Guard Act without unifying them. Through these revisions, special guards and police assigned to special guard duty may develop the civilian guard industry wholesomely under the law, and the civilians would have a wider range of options to choose from to receive high quality security service.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.930-936
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• 2010

There is very important to investigate long-term trend of soil chemical properties and quality index for sustainable agriculture and production of agricultural safety products. Monitoring on soil chemical properties in paddy soils was conducted as one cycle with 4 years from 1999 to 2007. Paddy soil samples were taken from 4,007, 1,970, 2,070 sites in 1999, 2003 and 2007, respectively. With these data, soil quality index (SQI) was evaluated by method that Yoon et al suggested in 2004. Chemical properties of paddy soils were 5.8 for pH, 24 g $kg^{-1}$ for organic matter, 132 mg $kg^{-1}$ for available phosphate, 0.29 cmol_c\; kg-1 for exchangeable potassium, 4.7 $cmol_c\;kg^{-1}$ for exchangeable calcium, 1.3 $cmol_c\;kg^{-1}$ for exchangeable magnesium and 126 mg $kg^{-1}$ for available silicate in 2007. Long-term change was shown that pH has increased gradually whereas exchangeable potassium has decreased. However, reasonably large changes were found. Exchangeable calcium and available silicate level in 1999 was 4.0 $cmol_c\;kg^{-1}$, 86 mg $kg^{-1}$, but had risen to 4.7 $cmol_c\;kg^{-1}$, 126 mg $kg^{-1}$ in 2007, respectively. The change of paddy soils quality index was increased gradually and increasement of silicate quality index was higher than other quality indicators.

• Journal of Plant Biotechnology
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• v.48 no.3
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• pp.179-185
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• 2021

Indoor gardening includes wall greening, terrariums, and flower arrangements. Among these types of indoor gardens, the terrarium is easy to access for the general public, but in Korea, because of the focus on esthetics, the original purpose of creating terrariums, which was to grow plants sustainably in an enclosed space, has been lost. In addition, miniaturization of plants is required to grow plants in an enclosed space. Since the available plant species suitable for a terrarium are limited, only plants such as succulents, cacti, and moss have been used. In this study, Bronze (X Graptosedum) was used, and these problems were solved using the following three methods: placement and growth of virus-free plants in the terrarium; extending the diversity of plants with minimal size that can be planted in terrariums; and reducing the price of in vitro plants with minimal size by achieving large-scale production. In particular, tissue-cultured succulents were developed into a Vivorium by replacing the tissue culture container and renewing the composition of the plant. This paper suggests a new indoor horticultural field, Vivorium, that can improve the current limitations of terrariums and make them more accessible to the general public. The introduction and popularization of new indoor gardening fields with the increase in single-person households and indoor activities in the Pandemic era can also improve psychological stability among people and in the society.

• (The) Research of the performance art and culture
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• no.37
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• pp.249-293
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• 2018

The Musical Theatre was a popular art genre that originated from the western musical tradition represented by the European opera. In the twentieth century, it bloomed around Broadway in the United States. It is also one of the commercial arts which is popularly loved by the public in the field of performing arts all over the world at present. Due to the nature of this genre, the development of dramas and the expression of characters use music, not words or gestures, as the main medium. And the style of music reacts sensitively to the taste of the public, not to a particular class. When Japan colonized Korea, the empire strongly believed modernization equaled westernization and Japan was the one who could awaken Korean. The Japanese colonial music education was intended to bring cooperation and obedience to Japan by forcibly injecting Japanese ideology and culture into Joseon people. The music education of colonialism with the textbook of the "Songs for public education(보통교육 창가집)" compiled by the Japanese government was a sparkstone for the conversion of the Korean musical identity to Japanese and Western music. In addition to the capitalistic economical mechanism for establishing a South Korean government friendly with the United States during the Cold War after liberation, and the rush of American Pop culture represented by 'the show stage in 8th US Arm' and 'movies' which are to be the influence of invisible 'new cultural imperialism', our traditional music was confined to the meaning of 'Korean music', meaning 'past music'. In Korea, after the liberation, the musical was introduced by the influx of American popular culture. In accordance with the cultural policy of Park Jeong-hee regime, which aimed to spread the 'healthy culture' through the modernization of traditional arts, 'The Yegreen(예그린악단)' was founded. However, the plan to create a contemporary performing art based on Korean national arts showed the possibility of success in 1966 with the success of , but soon after, they have been destined to fall into an institution that has lost their ability to operate on their own due to the suspension of the sponsorship of the regime. Due to the cultural imperialist strategy of the influence of Japanese imperialism's colonial music education and influx of American popular culture after liberation, in the early days of Korean musicals, our traditional aesthetic style brought about the situation of the 1960 's, which did not become an independent ethnic art through the exchange and expansion with Western music. This is the background of the western licensed musicals led by the Korean musical market in the 21st century as well as the main cause of musical creation based on western music.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.2
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• pp.3-34
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• 2018

Korea's air transport industry has a 70-year history since Korea National Airline was establishment in October 1948. Korea has 9 airlines which have international air transport business licenses, and as of 2017, air transport performance(Domestic & International) is ranked 8th in the world. Through analysis of Korea's air transport industry, this paper examines the essential problems of the domestic air transport industry and what policies and laws should be supplemented, and presents an "Policy Directions for the Air Transport Industry" that can continue to grow into a global aviation leading country in the future. Analysis of aviation statistics shows that the nation's air transport industry has a very high growth rate, and national airlines continue to invest in sustainable growth. Furthermore, new companies are also trying to enter the market. As of November 2018, four companies applied for licenses for international air transport business, one for international air transport business (cargo) license, and the Ministry of Land, Infrastructure and Transport is expected to decide whether to issue the license by first quarter of 2019. While some expect price reductions and consumer benefits through competition promotion, others worry about worsening airline financial structures and reducing safety investment due to competition. To sum up the problems of the nation's air transport industry, first, low-cost airlines focus only on attracting domestic demand, and thus have a weak foundation for continued growth. Second, the rapid growth in recent years has led to the lack of aviation professionals such as pilots and technicians and the saturation of slots at major airports. Third, since the financial soundness of airlines is not systematically managed, the financial situation of airlines can quickly deteriorate and the damage can be attributed to consumers. In order for the national airlines to continue to develop, the first is to focus on the endless demand of the global aviation market and to secure international competitiveness. Second, the government should support the airline infrastructure according to the size of the air transport industry, third, we will systematically nurture aviation experts who will lead the future of the nation's air transport industry, and finally, the government will have to continuously manage the financial status of airlines to prevent consumer damage in advance. Nowadays the air transport industry has become very competitive. Not only do airlines have to work hard for the sustainable development of national airlines, but all government agencies must support our airline companies in policy to win international competition.