• Journal of the Korean Society of Radiology
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• v.11 no.1
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• pp.9-17
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• 2017

A high degree of precision and accuracy in Gamma Knife Radiosurgery(GKRS) is a fundamental requirement for therapeutical success. Elaborate radiation delivery and dose gradients with the steep fall-off of radiation are clinically applied thus necessitating a dedicated Quality Assurance(QA) program in order to guarantee dosimetric and geometric accuracy and reduce all the risk factors that can occur in GKRS. In this study, as a part of QA we verified the accuracy of single-shot dose profiles used in the algorithm of Gamma Knife Perfexion(PFX) treatment planning system employing Variable Ellipsoid Modeling Technique(VEMT). We evaluated the dose distributions of single-shots in a spherical ABC phantom with diameter 160 mm on Gamma Knife PFX. The single-shots were directed to the center of ABC phantom. Collimating configurations of 4, 8, and 16 mm sizes along x, y, and z axes were studied. Gamma Knife PFX treatment planning system being used in GKRS is called Leksell GammaPlan(LGP) ver 10.1.1. From the verification like this, the accuracy of GKRS will be doubled. Then the clinical application must be finally performed based on precision and accuracy of GKRS. Specifically the width at the 50% isodose level, that is, Full-Width-of-Half-Maximum(FWHM) was verified under such conditions that a patient's head is simulated as a sphere with diameter 160mm. All the data about dose profiles along x, y, and z axes predicted through VEMT were excellently consistent with dose profiles from LGP within specifications(${\leq}1mm$ at 50% isodose level) except for a little difference of FWHM and PENUMBRA(isodose level: 20%~80%) along z axis for 4 mm and 8mm collimating configurations. The maximum discrepancy of FWHM was less than 2.3% at all collimating configurations. The maximum discrepancy of PENUMBRA was given for the 8 mm collimator along z axis. The difference of FWHM and PENUMBRA in the dose distributions obtained with VEMT and LGP is too small to give the clinical significance in GKRS. The results of this study are considered as a reference for medical physicists involved in GKRS in the whole world. Therefore we can work to confirm the validity of dose distributions for all collimating configurations determined through the regular preventative maintenance program using the independent verification method VEMT for the results of LGP and clinically assure the perfect treatment for patients of GKRS. Thus the use of VEMT is expected that it will be a part of QA that can verify and operate the system safely.

• Korean Journal of Psychosomatic Medicine
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• v.25 no.2
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• pp.176-184
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• 2017

Objectives : Middle aged women with depression often experience hot flush symptoms. It is still unclear about the association between depression and hot flush symptoms. Therefore, we investigated hormonal profile, functional somatic symptoms, coping styles and attitude for menopause between depressed women with hot flush and those without hot flush. Methods : This study included 33 depressed patients with hot flush symptoms and 33 depressed patients without hot flush symptoms. Hot flush was confirmed through prospective daily symptom ratings for a week. Subjects' coping styles were assessed by the stress coping checklist. Somatic symptoms were assessed by the Patient Health Questionnaire-15(PHQ-15). Sex hormonal levels were assayed by a radioimmunoassay. The Brief World Health Organization Quality of Life Assessment Instrument(WHOQOL-BREF) was used to evaluate quality of life. Results : In coping style, depressed women with hot flush symptoms used less 'problem-centered coping'($13.15{\pm}3.17$) and 'search for social support'($11.83{\pm}2.84$) than those without hot flush symptoms($15.17{\pm}3.1$, p=0.028 ; $14.25{\pm}3.22$, p=0.009 ; respectively). Depressed women with hot flush symptoms showed more negative attitude toward post-menopause, but its statistical significance was marginally insufficient(p=0.059). We did not find any group differences in sex hormonal levels and somatic complaints assessed by the PHQ-15. The score of social relationship domain of WHOQOL-BREF was significantly lower in subjects with hot flush symptoms($8.62{\pm}2.04$) than subjects without hot flush symptoms($9.71{\pm}1.65$ ; p=0.044). Conclusions : Among middle aged women with depression, the manifestation of hot flush symptoms was associated with coping styles and attitude for menopausal transition. Hot flush symptoms in depressed women negatively influence quality of life, so clinicians actively perform therapeutic approach in case of depressed patients with hot flush symptoms. In case of depressed patients who present hot flushes, cognitive behavior therapy or stress management might be an effective treatment option in company with antidepressants or hormonal treatment. Later, longitudinal study will be needed to evaluate risk factor, cause and effect associated with hot flush and depression.

• Korean Journal of Environment and Ecology
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• v.34 no.6
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• pp.589-600
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• 2020

Effective conservation and management of protected areas require monitoring the settlement of invasive alien species and reducing their dispersion capacity. We simulated the potential distribution of invasive alien plant species (IAPS) using three representative species distribution models (Bioclim, GLM, and MaxEnt) based on the IAPS distribution in the forest genetic resource reserve (2,274ha) in Uljin-gun, Korea. We then selected the realistic and suitable species distribution model that reflects the local region and ecological management characteristics based on the simulation results. The simulation predicted the tendency of the IAPS distributed along the linear landscape elements, such as roads, and including some forest harvested area. The statistical comparison of the prediction and accuracy of each model tested in this study showed that the GLM and MaxEnt models generally had high performance and accuracy compared to the Bioclim model. The Bioclim model calculated the largest potential distribution area, followed by GLM and MaxEnt in that order. The Phenomenological review of the simulation results showed that the sample size more significantly affected the GLM and Bioclim models, while the MaxEnt model was the most consistent regardless of the sample size. The optimal model overall for predicting the distribution of IAPS among the three models was the MaxEnt model. The model selection approach based on detailed flora distribution data presented in this study is expected to be useful for efficiently managing the conservation areas and identifying the realistic and precise species distribution model reflecting local characteristics.

• Journal of Chest Surgery
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• v.39 no.12 s.269
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• pp.920-926
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• 2006

Background: Mortality and morbidity of anastomotic complications after esophagectomy have gradually decreased in recent years. However, swallowing difficulties and reflux symptoms after esophagogastrostomy continue to be a burden jeopardizing the quality of life. In the present study, we evaluated the quality of esophagogastrostomy by analyzing anastomotic stenosis and reflux esophagitis. Material and Method: A retrospective analysis was made in 74 patients who underwent esophagogastrostomy after esophagectomy by one surgeon between January 1995 and December 2004. 53 patients of them received endoscopic examination during follow-up($29{\pm}23.6$ months, range $5{\sim}111$ months). Reflux esophagitis and stenosis at anastomostic site were analyzed according to the techniques and locations of esophagogastrostomy. Result: The median age at the time of repair was $60.3{\pm}8.87$ years(range $39{\sim}81$ years). 23 patients received a hand-sewn esophagogastric anastomosis and 30 patients a circular stapled one. There was no significant statistical difference in terms of anastomotic stenosis(p=0.64) and reflux esophagitis(p=0.41) between the two groups. Cervical anastomosis was peformed in 26 patients and intrathoracic anastomosis in 27 patients. No significant statistical difference in anastomotic stenosis between the two groups was found(p=0.44), but reflux esophagitis was noted in 3 patients in the cervical anastomosis group and 14 patients in the intrathoracic anastomosis group(p=0.003). Conclusion: Cervical anastomosis was supposed to have a better quality of esophagogastrostomy by lowering the risk of reflux esophagitis. In the future, the comprehensive study including a patient's subjective symptom and Barrett's metaplasia should be performed in larger cases.

• Korean Chemical Engineering Research
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• v.51 no.2
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• pp.221-225
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• 2013

Sustainability, in general, means the protection of environmental resources and economic prosperity, with the consideration of the social, economic and environmental effect, as well as human health and the enhancement of life. Profound consideration about sustainability has to handle the overall cycle of feedstock, resource extraction, transportation and production in addition to the environmental effect. Sustainable development of the chemical industries should be carried out complementarily by strengthening the chemical process safety of the industries. In this respect, chemical process safety can be called an opportunity to enhance the compatibility internationally. Changing new paradigm in chemical process safety is formed from the overall life cycle considering basic design of existing systems and production processes. To improve the chemical process safety, the integrated smart system is necessary, comprising various chemical safety database and knowledge base and improved methods of quantitative risk analysis, including management system. This paper discussed the necessity of overall life cycle in chemical process safety and proposed new technology to improve the sustainability. To develop the sustainable industries in process systems engineering, three S, which include Safety, Stability and Security, will have to be combined appropriate.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.3
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• pp.297-303
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• 2018

This study investigated the effect of community-based health intervention program to improve metabolic disease in Jeju island. There were 50 obese local residents in the experimental group (body mass index, $BMI{\geq}25kg/m^2$). They participated in cooking therapy with nutrition education (4 times), exercise program with proprioceptive neuromuscular facilitation (PNF) and stretching training (9 times), and alternative medicine program with healing touch massage (3 times) during a 3-week period. To evaluate the effectiveness of the program, body composition, blood lipid profiles, blood glucose, and waist circumference were assessed before and after the intervention program. After the program, the value of total cholesterol (TC), glycosylated hemoglobin (HbA1C), diastolic blood pressure, percent body fat, and waist circumference were decreased, and became the normal value. Especially, HbA1C, percent body fat, and waist circumference were significantly decreased (P<0.001) in the experimental group, while HbA1C, percent body fat, and waist circumference were significantly increased (P<0.001) in the control group (N=50), who had no intervention. Our results suggest that metabolic syndrome associated markers need intervention program for improving them. In conclusion, although this study did not analyze the effect of the health intervention program and cooking therapy separately, considering the result of this 3-week, short term program, the effect will be more profuse if cooking therapy and exercise program were performed concurrently.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.125-134
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• 2017

Unusual precipitation caused by typhoons and severe rain stormscan threaten human life and property. Thus, various organizations prepare emergency action plans (EAPs) to provide proper guidelines for operators, experts, and emergency response personnel to protect and enhance critical infrastructure. For example, FEMA and DHS have various types of EAPs for dams, levees, and other structures to protect people and property. FEMA defines EAPs as official documents to decrease the damage and impact in emergency situations and to reduce casualties. These documents should consider all possible situations in an emergency and can reduce problems in facility management. This study analyzes EAPs for infrastructure from the USA, Japan, and Korea in order to suggest an ideal EAP framework. EAPcontent can include how to guide experts and operators in disaster stages (mitigation, preparedness, response, and recovery), how to operate emergency equipment, and how to protect critical infrastructure and life. The suggested EAP framework performed very well in a test location. It can therefore be used for infrastructure organizations in Korea and to inform of the appropriate processes and methods for risk reduction in flood disasters.

• Korean Journal of Psychosomatic Medicine
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• v.24 no.2
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• pp.133-139
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• 2016

Objectives : As the prevalence of elderly depression increases, it becomes urgent problem to provide preventive and management measures. But in practice, it is difficult to detect depression in early stage. The purpose of this study is to evaluate the association between sociodemographic factors and depression in elderly welfare facility users in a city. Methods : In this research, the severity of depression and sociodemographic factors(gender, age, education, co-morbid disease, housing type, number of children, number of family members living with the subjects) was evaluated through PHQ-9 and interview. Using the data, the associations of depression and sociodemographic factors were analyzed. Based on PHQ-9 depression cut-off value(10 points), the subjects were divided into two groups, and the difference of the variables between groups were analyzed statistically. Results : 'Own house'(YES/NO), education(less than elementary school graduation/more than elementary school graduation) were sociodemographic factors which showed significance difference in mean PHQ-9 scores. Group with Over PHQ-9 10 points showed less 'having their own house' and less education level than group with less PHQ-9 10 points. Conclusions : With this research, it is expected that the risk factors for the elderly depression can be understood and the measures for early detection and invention of elderly depression would be provided.

• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.35-44
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• 2021

The PR (Photo Resist) process in the semiconductor process is a process that uses a mixture of flammable substances. Due to the process equipment is installed in a clean room and when flammable substances leak, there is a high risk of suffocation, fire, and explosion. It is necessary to analyze the impact of accidents that may occur during operation and to evaluate whether the safety of workers can be guaranteed. In this study, the value of radiant heat and temperature change at the monitor point set up virtual inside the clean room was confirmed through CFD simulation of 10 leak and fire scenarios using the FLACS CFD - Fire Module. A fire that occurs inside a clean room transfers high radiant heat to the inter-story structure, but its scope is quite limited, and it is unlikely that it will collapse in a single fire accident. There was no scenario in which two stairs leading to the exit were exposed to high radiant heat at the same time due to a fire accident, therefore workers were able to escape in case of a fire. In addition, it was confirmed that the level of radiant heat and temperature rise rapidly decreased as they moved downstairs. According to the API 520 standard, workers exposed to 6.31 kW/m² of radiant heat that workers can withstand for 30 seconds were confirmed that it was possible to sufficiently escape from the inside.

• Journal of Nutrition and Health
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• v.52 no.4
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• pp.332-341
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• 2019

Purpose: Poor nutrition in hospitalized patients is closely linked to an increased risk of infection, which can result in complications affecting mortality, as well as increased length of hospital stay and hospital costs. Therefore, adequate nutritional support is essential to manage the nutritional risk status of patients. Nutritional support needs to be preceded by nutrition screening, in which accuracy is crucial, particularly for the initial screening. To perform initial nutrition screening of hospitalized patients, we used the Catholic Kwandong University (CKU) Nutritional Risk Screening (CKUNRS) tool, originally developed at CKU Hospital. To validate CKUNRS against the Patient-Generated Subjective Global Assessment (PG-SGA) tool, which is considered the gold standard for nutritional risk screening, results from both tools were compared. Methods: Nutritional status was evaluated in 686 adult patients admitted to CKU Hospital from May 1 to July 31, 2018 using both CKUNRS and PG-SGA. Collected data were analyzed, and the results compared, to validate CKUNRS as a nutrition screening tool. Results: The comparison of CKUNRS and PG-SGA revealed that the prevalence of nutritional risk on admission was 15.6% (n = 107) with CKUNRS and 44.6% (n = 306) with PG-SGA. The sensitivity and specificity of CKUNRS to evaluate nutritional risk status were 98.7% (96.8 ~ 99.5) and 33.3% (28.1 ~ 39.0), respectively. Thus, the sensitivity was higher, but the specificity lower compared with PG-SGA. Cohen's kappa coefficient was 0.34, indicating valid agreement between the two tools. Conclusion: This study found concordance between CKUNRS and PG-SGA. However, the prevalence of nutritional risk in hospitalized patients was higher when determined by CKUNRS, compared with that by PG-SGA. Accordingly, CKUNRS needs further modification and improvement in terms of screening criteria to promote more effective nutritional support for patients who have been admitted for inpatient care.