• Imaging Science in Dentistry
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• v.33 no.3
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• pp.143-149
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• 2003

Purpose: To investigate the radiosensitivity of the normal human oral keratinocytes (NHOK), and the effect of irradiation on cell cycle and protein expression. Materials and Methods: To evaluate the radiosensitivity of NHOK, the number of colonies and cells were counted after irradiation and the SF2 (survival fraction at 2Gy) value, and the cell survival curve fitted on a linear-quadratic model were obtained. LDH analysis was carried out to evaluate the necrosis of NHOK at 1, 2, 3, and 4 days after 2, 10, and 20 Gy irradiation. Cell cycle arrest and the induction of apoptosis were analyzed using flow cytometry at 1, 2, 3, and 4 days after 2, 10, and 200y irradiation. Finally, proteins related cell cycle arrest and apoptosis were analysed by Western blot. Results: The number of survived cell was significantly decreased in a dose-dependent manner. The cell survival curve showed SF2, α, and β values to be 0.568, 0.209, and 0.020 respectively. At 200y irradiated cells showed higher optical density than the control group. After irradiation, apoptosis was not observed but G2 arrest was observed in the NHOK cells. 1 day after 10 Gy irradiation, the expression of p53 remained unchanged, the p2l/sup WAF1/Cipl/ increased and the mdm2 decreased. The expression of bax, bcl-2, cyclin B1, and cyclin D remained unchanged. Conclusion: These results indicate that NHOK responds to irradiation by G2 arrest, which is possibly mediated by the expression of p21/sup WAFl/Cipl/, and that cell necrosis occurs by high dose irradiation.

• Tuberculosis and Respiratory Diseases
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• v.72 no.2
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• pp.163-168
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• 2012

Background: Cigarette smoke induced release of iron could alter iron metabolism in the lungs of chronic smokers and contribute to the increase in the total oxidative burden on the lungs of smokers. In previous studies, ferritin levels of bronchoalveolar lavage fluid in smokers were elevated. The aim of the present study was to investigate the relationship between serum ferritin concentration, smoking and lung function in Korean people. Methods: This study was based on the data acquired in the second year (2008) of the Forth National Health and Nutrition Examination Survey that was conducted from 2007 to 2009. The analysis included 2,244 subjects who were older than 20 years and had complete data from both lung function test and serum ferritin concentration. Among participants, 1,076 were male and 1,168 were female. Results: Mean serum ferritin concentrations in males were $120.3{\pm}80.1{\mu}g/L$ and $47.9{\pm}39.8{\mu}g/L$ in females. There were no differences in serum ferritin concentrations between non-smokers and smokers after adjusting for age, body mass index, and amounts of alcohol. Serum ferritin concentrations were associated with smoking amounts by simple linear regression but not associated with smoking amounts after adjustment with age, body mass index, and amounts of alcohol in both males and females. Lung function was not associated with serum ferritin concentrations. Conclusion: Our data suggested that serum ferritin concentrations are not related with smoking and lung function.

• Publications of The Korean Astronomical Society
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• v.28 no.3
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• pp.55-63
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• 2013

Gyupyo (圭表, Gnomon) consists of Gyu (圭, Measuring Scale) and Pyo (表, Column), and was one of the traditional astronomical instruments in East Asia. Daegyupyo (Large Gnomon) was manufactured in the Joseon dynasty around 1434 ~ 1435. To increase the measurement accuracy, it was equipped with a Hoengyang (橫梁, Cross-bar) and used a Youngbu (影符, Shadow-Definer) which was invented during the Yuan dynasty (1271 ~ 1368). The cross-bar was installed on the top of the column and this structure was called Eol. In addition, three plumbs hanging from the cross-bar was employed to vertically built Eol on the measuring scale. This method was also used to not only check the vertical of Eol but also diagnose the horizontal of the cross-bar. Throughout this study, we found that a cross-bar in a gnomon has played three important roles; measurement of the shadow length made by the central part of the Sun, increase of the measurement precision using the shadow-definer, and diagnosis of the vertical of Eol and the horizontal of the cross-bar itself using the three plumbs. Hence, it can be evaluated that the employment of a cross-bar and a shadow-definer in a gnomon was a high technology in the contemporary times. In conclusion, we think that this study is helpful for understanding the Large Gnomon of the Joseon dynasty.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.6
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• pp.367-380
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• 2014

Tsunami take away life, wash houses away and bring devastation to social infrastructures such as breakwaters, bridges and ports. The targeted coastal structure object in this study can be damaged mainly by the tsunami force together with foundation ground failure due to scouring and liquefaction. The increase of excess pore water pressure composed of oscillatory and residual components may reduce effective stress and, consequently, the seabed may liquefy. If liquefaction occurs in the seabed, the structure may sink, overturn, and eventually increase the failure potential. In this study, the solitary wave was generated using 2D-NIT(Two-Dimensional Numerical Irregular wave Tank) model, and the dynamic wave pressure acting on the seabed and the estimated surface boundary of the vertical revetment. Simulation results were used as an input data in a finite element computer program(FLIP) for elasto-plastic seabed response. The time and spatial variations in excess pore water pressure, effective stress, seabed deformation, structure displacement and liquefaction potential in the seabed were estimated. From the results of the analysis, the stability of the vertical revetment was evaluated.

• Progress in Medical Physics
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• v.27 no.1
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• pp.46-53
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• 2016

Periodical calibrations of radiation detectors are important for accurate quality assurance of therapeutic linac. The measuring instruments such as ion-chamber, thermometer, barometer, and survey meter should be calibrated periodically. Period of calibration for these instruments is suggested 6 month to one year in Korea and two years in other countries nowadays. Therefore, the determination of reasonable period for calibration is needed. In this study, we plan to utilize the results of these survey; frequent in use, how to use and stability of instruments, to determine the optimized period of calibration for the instruments in the departments of radiation oncology in Korea based on the ILAC-G24. The SurveyMonkey web-based survey tool was used and the objects of survey were 18 department of radiation oncology in university hospitals, and 15 departments were answered. The 64 questionnaires which supposed to be answered in 50 minutes were classified as the information of candidates, the thermometer, the barometer, the surveymeter, and the ion-chamber. The thermometers and the barometers were not under periodical calibration for more than half of candidates. The periods of calibration of surveymeters were 6 month to 1 year. We expect that the calibration period can be determined based on these survey results.

• Applied Microscopy
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• v.21 no.2
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• pp.76-95
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• 1991

A single injection of cadmium chloride (3.75 mg/kg) was made into the peritoneal cavities of albino rats. The cortices of kidney were obtained from the experimental animals at 3 hr., 6 hr., 12 hr., 24 hr. and 36 hr. after administration of cadmium chloride, respectively. The specimens of each experimental animal were prefixed in 2% glutaraldehyde-4% paraformaldehyde solution for $2{\sim}4$ hours, and these specimens were post-fixed in 1% osmic acid. After fixation, the specimens were dehydrated with alcohol and acetate and embedded in Epon 812. Ultrathin sections, $600{\sim}800{\AA}$ thickness were made and stained with uranyl acetate and lead citrate. And all the preparations were observed with Hitachi-600 transmission electron microscope. The results obtained were as follows: 1. The main changes in ultrastructures of the glomeruli observed at 3 hr. after cadmium chloride administration include loss of filtration slit and fenestrae of capillary endothelium that was resulted from thickings of the basal lamina and fusion of pedicels of the podocytes. At 12 hr. after cadmium chloride administration the Bowman's capsules were mostly filled with abnormally thickened and fused pedicels. After 24 hr. however, the only recognized change was loss of fenestrae of the capillary endothelium. And the ultrastructure of the glomeruli were almost normal in 36 hr. after cadmium chloride treatment. 2. At 3 hr. after treatment with cadmium chloride, in the renal tubular cells the vesicles and vacuoles increased in number at the apical portion, of the tubular epithelial cells, the basal infoldings were reduced and the basal lamina was thickened. After 12 hr., a number of phagosomes appeared at the apical portion and the cisternae of rough endoplasmic reticulum were swollen. At 24 hr. after cadmium chloride administration irregularly shaped mitochondria were observed in the apical area, and mitochondria with swollen cristae were found at the basal portion. And after 36 hr. The ultrastructures of the epithelial cells appeared almost normal except for a moderate increase in the number of vesicles and vacuoles. Consequently it is suggested that in albino rats, cadmium chloride induces acute reversible degenerative changes in the glomeruli as well as in the epithelial cells of the proximal convoluted tubules.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.1
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• pp.25-34
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• 2017

The objective of this study is to seek for improvement measures to make the Ecosystem and Nature Map by analyzing causes for grade changes and distributional characteristics of areas with public objections to the Ecosystem and Nature Map notified by e-official gazette from 2014 to June 2016. The receipt of public appeals has been recently increased from average 23 cases a year(2007-2013) to average 33 cases a year(2014-June 2016) while there were 42 areas with public appeals for less than the minimum area($62,500m^2$) for the evaluation of grade of the Ecosystem and Nature Map. Most of the public appeals focused on the 1st grade zone of the Ecosystem and Nature Map. Before grade changes by public appeals, the 1st grade zone of the Ecosystem and Nature Map were 76.0% of the whole areas with public appeals. However, after grade changes by public appeals, it was rapidly decreased to 25.2%, which means that a lot of the 1st grade zone with public appeals were lowered. In the results of analyzing the distributional characteristics of areas with public appeals, they were mostly distributed in lowland(less than 250m altitude), section with $10{\sim}20^{\circ}$ slope, and areas close to or within 100m from built-up area. Regarding areas with public appeals, the biggest time difference between the period of the existing research by National Ecosystem Survey and the period of notice after completing the treatment of public appeals was 18 years while areas showing 6-15 years of time difference were about 70%. Thus, there were huge differences in time of research and notice. Also, the biggest causes for grade changes were boundary errors caused by small-scale survey, and then followed by changes in evaluation of endangered species and occurrence of built-up area and damaged land. Analyzing areas with public appeals in each evaluation item of the Ecosystem and Nature Map, vegetation part was 73.0%, and endangered species area was 23.1% while topography and wetland was less.

• Development and Reproduction
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• v.10 no.1
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• pp.47-54
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• 2006

The Tridentiger obscurus were collected of Ocheon-dong and Dolsan-do in Yeosu from Apirl to July 2003, and were carried to the laboratory to investigate their development of spawning habit, egg development, larvae and juveniles. The fertilized eggs were measured $0.86{\sim}1.07{\times}0.53{\sim}0.74\;mm$ in diameter. Hatching of the embryo began about 154 hrs 40 mins after fertilization in water temperature of $18.4{\sim}23.2^{\circ}C$(mean $21.2^{\circ}C$). The newly-hatched larvae were $2.72{\sim}2.87mm$(mean 2.83mm) in total length (TL), their mouth and anus were opened, and the yolk sac was completely absorbed. At 21 days after hatching, the postlarvae were $5.32{\sim}7.23mm$(mean 6.02mm) TL, and the tip of the caudal notochord was flexed $45^{\circ}$ upward. The juveniles stage was reached when all fin-rays were formed at 45 day after hatching, and $11.62{\sim}14.32mm$(mean 13.45mm) TL.

• Journal of Hospice and Palliative Care
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• v.23 no.3
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• pp.103-113
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• 2020

A clinical practice guideline for patients in the dying process in general wards and their families, developed through an evidence-based process, is presented herein. The purpose of this guideline is to enable a peaceful death based on an understanding of suitable management of patients' physical and mental symptoms, psychological support, appropriate decision-making, family care, and clearly-defined team roles. Although there are limits to the available evidence regarding medical issues in patients facing death, the final recommendations were determined from expert advice and feedback, considering values and preferences related to medical treatment, benefits and harms, and applicability in the real world. This guideline should be applied in a way that takes into account specific health care environments, including the resources of medical staff and differences in the available resources of each institution. This guideline can be used by all medical institutions in South Korea.

• Korean Security Journal
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• no.36
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• pp.443-467
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• 2013

The purpose of this study is to introduce United States Coast Guard (USCG) in order to suggest a direction to advance the system of Korea Coast Guard. After the effect of United Nations on the Law of the Sea in 1994, the world is facing with new era of maritime age with emergence of new maritime border 'Exclusive Economic Zone(EEZ)'. Along with new maritime era, Korea also has been facing with the conflicts caused from EEZ. Also, there is a increasing concern about maritime safety and security since people looking for maritime tourism and leisure sports are dramatically increasing in Korea. Moreover, national security matters are a big issue in Korea due to the several incidents occurred in the sea such as the attack on Yeon-Pyung Island and the sinking of Cheonan naval vessel. Arising concern on these issues in maritime space requires Korea Coast Guard to handle these effectively. However, the systematical and structural limitation of Korea Coast Guard limits the effective management of recent issues. The United States Coast Guard which is considered as one of the military force in the United States has continuously reformed and developed its system and structure to better handle the maritime safety and security issues through developing project such as the Integrated Deep Water system. Also, maritime police system and structure in the United States is different with in Korea. This study expects to suggest a way to advance the system and structure of Korea Coast Guard through examination of United States Coast Guard and comparing maritime police system and structure between Korea and the United States in order to properly deal with the maritime safety and security issues arising recently.