• Progress in Medical Physics
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• v.26 no.2
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• pp.87-92
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• 2015

The gated RapidArc may produce a dosimetric error due to the stop-and-go motion of heavy gantry which can misalign the gantry restart position and reduce the accuracy of important factors in RapidArc delivery such as MLC movement and gantry speed. In this study, the effect of stop-and-go motion in gated RapidArc was analyzed with varying gating window time, which determines the total number of stop-and-go motions. Total 10 RapidArc plans for treatment of liver cancer were prepared. The RPM gating system and the moving phantom were used to set up the accurate gating window time. Two different delivery quality assurance (DQA) plans were created for each RapidArc plan. One is the portal dosimetry plan and the other is MapCHECK2 plan. The respiratory cycle was set to 4 sec and DQA plans were delivered with three different gating conditions: no gating, 1-sec gating window, and 2-sec gating window. The error between calculated dose and measured dose was evaluated based on the pass rate calculated using the gamma evaluation method with 3%/3 mm criteria. The average pass rates in the portal dosimetry plans were $98.72{\pm}0.82%$, $94.91{\pm}1.64%$, and $98.23{\pm}0.97%$ for no gating, 1-sec gating, and 2-sec gating, respectively. The average pass rates in MapCHECK2 plans were $97.80{\pm}0.91%$, $95.38{\pm}1.31%$, and $97.50{\pm}0.96%$ for no gating, 1-sec gating, and 2-sec gating, respectively. We verified that the dosimetric accuracy of gated RapidArc increases as gating window time increases and efforts should be made to increase gating window time during the RapidArc treatment process.

• Journal of agricultural medicine and community health
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• v.29 no.2
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• pp.265-285
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• 2004

Objectives: The acute toxic effects of pesticide are well known. Concern has also been expressed that long-term exposure may result in damage to the central nervous system. This study was conducted to test the hypothesis that central nervous system symptoms might occur due to pesticide exposure. Methods: In a cross-sectional study, first, cumulative exposure index (CEI) was estimated. Neurologic symptoms (Q-16 questionnaire) for 541 farmers (exposed to pesticides) were compared with 119 non-exposed persons in spraying season nine rural areas in Korea. Results: The pesticides poisoning rates for last 3 months were 67.2% for orchard farmers, 55.3%for dry field farmers, and 20.5% for husbandry farmers, respectively, showing significant difference (p<0.001). Compared with non-exposure group, exposure groups (especially, orchard farmers) reported significantly more neurologic symptoms and had a higher overall neurological symptoms score (p<0.001). Factors related to the positive neurological symptoms (answers "yes" to six or more of Q-16 questionnaire) adjusted for age, sex, education level, smoking and alcohol drinking were type of farming (OR 3.08, 95% CI 1.50-6.30 in orchard farmers vs non-exposure group), CEI (OR 2.75, 95% CI 1.12-6.78 in Q3 vs Q1), past poisoning (OR 1.97, 95% CI 1.21-3.20 vs normal), current mild poisoning (OR 3.03, 9500 CI 1.47-6.22 vs normal) and current moderate poisoning (OR 6.34, 95% CI 3.03-13.25 vs normal), respectively. Conclusions: These results suggest that long-term exposure to pesticides appears to be associated with subtle changes in the central nervous system.

• Restorative Dentistry and Endodontics
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• v.34 no.2
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• pp.87-94
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• 2009

The purpose of this study was to assess the current materials, methods and difficulties according to the year of licence and educational background of Korean dentists in Class II direct composite resin restorations. Total 17 questions were included in the questionnaire. Questions were broadly divided into two parts: first. operator's information. and second. the materials and methods used in Class II posterior composite restoration. The questionnaire was sent to dentists enrolled in Korean Dental Association via e-mail. Total 12,193 e-mails were distributed to dentists. 2,612 e-mails were opened, and 840 mails (32.2%) were received from respondents. The data was statically analyzed by chi-square test using SPSS(v. 12.0.1, SPSS Inc. Chicago, IL, USA). Male dentists among respondents was 79%. 60.3% of the respondents acquired their licences recently (1998-2007), and 77% practiced in private offices. 83.4% have acquired their knowledge through school lectures, conferences and seminars. For the Class II restorations, gold inlays were preferred by 65.7% of respondents, while direct composite resin restorations were used by 12.1 % amalgam users were only 4.4% of respondents. For the restorative technique, 74.4% of respondents didn't use rubber dam as needed. For the matrix. mylar strip (53.4%), metal matrix (33.8%) and Palodent system (6.5%) were used. 99.6% of respondents restored the Class II cavity by incremental layering. Obtaining of the tight interproximal contact was considered as the most difficult procedure (57.2%) followed by field isolation (21 %). Among various bonding systems, 22.6% of respondents preferred SE Bond and 20.2% used Single Bond. Z-250 was used most frequently among a variety of composite resins.

• Korean Journal of Optics and Photonics
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• v.28 no.5
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• pp.203-212
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• 2017

A scientific model refers to a conceptual system that can describe, explain, and predict a particular physical phenomenon. The co-construction of the scientific model is attracting attention as a new teaching and learning strategy in the field of science education and various studies. The evaluation and modification of models compared with the predicted models of data from the real world is the core of modeling strategy. However, there were only a limited data provided by the teacher in many studies of modeling comparing the students' predictions of their own models. Most of the students were not given the opportunity to evaluate the suitability of the model with the data in the real world. The purpose of this study was to develop a scientific model co-construction program that can evaluate the model by directly comparing the predicted models with the observed data from the real world. Through a collaborative discussion between teachers and researchers for 6 months, a 5-session scientific model co-construction program on the subject 'image formation by convex lenses' for second grade middle school students was developed. Eighty (80) students in 3 classes and a science teacher with 20 years of service from general public co-educational middle school in Gyeonggi-do participated in this 2-week program. After the class, students were asked about the helpfulness and difficulty of the class, and whether they would like to recommend this class to a friend. After the class, 95.8% of the students constructed the scientific model more than the model using the construction rule. Students had difficulties to identify principles or understand their friends, but the result showed that they could understand through model evaluation experiment. 92.5% of the students said that they would be more than willing to recommend this program to their friends. It is expected that the developed program will be applied to the school and contribute to the improvement of students' modeling ability and co-construction ability.

• Journal of dental hygiene science
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• v.18 no.6
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• pp.389-397
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• 2018

The purpose of this study was to examine the self-rated oral health status of industrial workers and influential factors for their work loss caused by dental care in an effort to prepare some information on policy setting about the promotion of the oral health of industrial workers and on the prevention of their oral diseases. The married industrial workers experienced work loss due to dental care more commonly than did the unmarried workers ($x^2=5.10$, p<0.05). In addition, the workers who found themselves to be in worse health experienced significantly more work loss ($x^2=29.69$, p<0.001). The workers who received treatment for oral diseases experienced significantly more work loss than those who did not receive treatment ($x^2=14.60$, p<0.001). In addition, the workers who had oral symptoms requiring treatment experienced more work loss than the others who not ($x^2=11.08$, p<0.01). The experience of not receiving treatment for a perceived oral disease was more dominant among the workers who found themselves to have an oral disease but did not receive treatment than among those who received treatment (p<0.001). Regarding factors affecting the work loss of the industrial workers caused by dental care, the workers whose monthly mean income was larger and who found themselves to be in worse health had significantly more experience of absenting themselves from the office or of leaving work early (p<0.001).

• Journal of Nutrition and Health
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• v.52 no.1
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• pp.58-72
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• 2019

Purpose: This study examined the food and nutrient intake of Korean elderly according to the anxiety and depressive condition using the data from the Korea National Health and Nutrition Survey (KNHANES) from 2013 to 2015. Methods: The participants were 3,504 elderly people over 65 years of age (1,523 in men and, 1,981 in women). The dietary information was analyzed using the 24-hour recall data. The anxiety and depressive state was assessed using the self-reported scale EQ-5D in the quality of life dimension. The subjects were divided into the anxiety depression group (AD) and non-anxiety depression group (NAD) according to their anxiety and depressive conditions. Results: In the male elderly, the AD group had a significantly lower education and economic level and higher proportion in living alone than the NAD group. The percentage of eating lunch and dinner alone in the male AD group was higher than that of the NAD group. The female AD group showed less a lower frequency of dinner than the NAD group. The male AD group had a lower consumption of total foods, fish and shellfishes, seaweeds, mushrooms, oils and fats, and seasonings than the NAD group. With regard to the nutrient intake, the male elderly NAD group had more sufficient nutrient intakes than the AD group. In particular, the daily intakes of dietary fiber, riboflavin, niacin, potassium and iron were significantly lower in the AD group. To compare with the nutrient density of the two groups, the vitamin C and niacin intakes were lower in the AD group than in the NAD group. Overall, the nutritional status of the male AD group was significantly lower than that of the NAD group. Meanwhile, the female elderly had showed a smaller difference in nutrient intake according to their anxiety and depressive condition. Conclusion: These results of this study show that more nutritional education and emotional support are needed to improve the nutritional status and health of the male elderly with anxiety or depression.

• Korean Journal of Heritage: History & Science
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• v.54 no.2
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• pp.194-215
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• 2021

Termites are important decomposers in the ecosystem. They are also economically significant structural pests. In this study, we reviewed the developments of termite control and recent research on termite management to provide information on the prevention and control of termites. In Korea, most of the damage to wooden historical buildings is caused by subterranean termites. Reticulitermes speratus kyushuensis is the main species, which is widely found throughout the country. In the early 1900s, inorganic insecticides, such as arsenic dust, were used for termite control. After the synthesis of chlorinated hydrocarbon pesticide in the 1940s, it was widely utilized and demonstrated high termite control efficacy. However, chlorinated hydrocarbon insecticides were later banned, disappearing from markets after reports emerged concerning environmental contamination and toxicity to humans. Therefore, the termite control industry sought a new termiticide; hence many pesticides were utilized for termite control. Organophosphate (1960s), carbamate (1970s), pyrethroid, and insect growth inhibitor (1980s) were newly synthesized and adopted. In the 1990s, the first commercial baits using chitin synthesis inhibitors (CSI) were developed, providing a means to eliminate an entire colony of subterranean termites around a structure. Many studies have been carried out on soil termiticides (liquid termiticides) and CSI baits to increase their efficacy, and different baits such as aboveground bait stations, fluid bait, and high-durability bait were also developed in the 2000s. In addition, the paradigm of termite control has shifted from localized treatments using soil termiticides to area-wide pest management using CSI baits to create termite-free zones and protect buildings over time. Termite infestations in wooden historical buildings in Korea have been reported since 1980, and considerable attention was drawn in the 1990s when several UNESCO world heritages such as the Jongmyo Shrine and the Janggyeong Panjeon Depositories of Haeinsa Temple were infested by subterranean termites. Since then, a survey of termite infestation in wooden architectural heritage has been conducted, and the National Research Institute of Cultural Heritage and Heritage Care Program regularly monitors those properties. Finally, we suggest termite management using primarily CSI baits, selective application of various soil treatments applied to the object, foundation soil treatment, research and development of durable termite baits, application of area-wide programs for wooden-building complexes, application of integrated termite management (ITM), and regular education for owners and managers to prevent and reduce termite damage.

• Journal of Nutrition and Health
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• v.54 no.4
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• pp.383-397
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• 2021

Purpose: The purpose of this study was to evaluate the change in the use of home meal replacement (HMR) and delivered foods and food habits of college students due to coronavirus disease 2019 (COVID-19). Methods: A survey was conducted on 460 male and female college students in Chungcheong province in December 2020. Results: The methods of participation in classes in the 2nd semester of 2020 were 40.2% for '100% non-face-to-face' and 40.4% for 'more than 70.0% of non-face-to-face classes'. 52.8% of the subjects responded that their physical activity had decreased, while 36.1% of the subjects responded that their body weight had increased over the past 6 months. Regarding the use of HMR, 62.7% of the male students and 69.6% of the female students responded with '1-2 times a week or less' before the outbreak of COVID-19. After the outbreak, 57.4% of males and 46.7% of females responded with '3-4 times a week or more' (p < 0.05, p < 0.001). As for the use of delivered food, 58.3% of the females responded with '2-3 times a month or less' before the outbreak, whereas the rate of responding with '1 or more times a week' after the outbreak was 64.6% (p < 0.001). Negative changes in food habits caused by COVID-19 were in the order of irregular meals (56.7%), increased intake of delivered food (42.2%), increased intake of snacks (33.3%), and increased intake of processed foods such as HMR (30.4%). Conclusion: As mentioned above, many college students had non-face-to-face classes due to COVID-19. During this period, they experienced decreased physical activity, weight gain, and undesirable eating habits such as irregular meal time, and increased intake of processed foods, delivery foods, and snacks. Therefore, there is a high need for nutrition education and policy support for the prevention and management of health and nutrition problems of college students, which can be caused due to the COVID-19 pandemic.

• Journal of Practical Agriculture & Fisheries Research
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• v.11 no.1
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• pp.79-94
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• 2009

The research project was conducted to develop a paper bagging machine for grape. This technology was aimed to highly reduce a labor for paper bagging in grape and bakery. In agriculture labor and farm population has rapidly decreased since 1980 in Korea so there was so limit in labor. In particular there is highly population in women and old age at rural area and thus labor cost is so high. Therefore a labor saving technology in agricultural sector might be needed to be replaced these old age with mechanical and labor saving tool in agriculture. The following was summarized of the research results for development of a paper bagging machine for grape. 1. Development of a new paper bagging machine for grape - This machine was designed by CATIA VI2/AUTO CAD2000 programme. - A paper bagging machine was mechanically binded a paper bag of grape which should be light and small size. This machine would be designed for women and old age with convenience during bagging work at the field site. - This machine was manufactured with total weight of less than 350g. - An overage bagging operation was more than 99% at the actual field process. - A paper bagging machine was designed with cartridge type which would be easily operated between rows and grape branches under field condition. - The type of cartridge pin was designed as a C-ring type with the length of 500mm which was good for bagging both grape and bakery. - In particular this machine was developed to easily operated among vines of the grape trees. 2. Field trials of a paper bagging machine in grape - There was high in grape quality as compared to the untreated control at the application of paper bagging machine. - The efficiency of paper bagging machine was 102% which was alternative tool for the conventional. - The roll pin of paper bagging machine was good with 5.3cm in terms of bagging precision. - There was no in grape quality between the paper bagging machine and the conventional method. - Disease infection and grape break was not in difference both treatments.

• 한국노년학
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• v.29 no.1
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• pp.329-352
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• 2009

This study examined life in old age and images of the aged perceived by middle-aged and old-aged generations through indepth interviews with 30 persons aged 40s through 80s residing in three areas (city or county) in capital region in Korea to use it as basic information in planning social welfare policy and reorganizing social services in response to population aging in capital region in Korea. In terms of economic life of the middle-aged and olde-aged generations perceived older people's opportunities for work were rarely given to the aged due to ageism and negative stereotypes of aging and the aged, and the aged tended to regard themselves less able or unable to work. In terms of social life of the aged both middle-aged and old-aged generations perceived that the frequency of social participation was low, and the daily life of the aged was found mostly aimless, unorganized and unplanned. In terms of psycho-social life of the aged both generations still felt that they were not alienated from the family, neighbors, and the society. In terms of social welfare services both generations thought the aged needed basic services such as income maintenance, health care, housing services, and particularly they felt lack of social services. The old-aged generation was willing to travel to the distance taking more than one hour to receive social services that they would need. Both the middle-aged and the old-aged agreed upon the necessity of preparation for old age and the benefits of earlier preparation, however, they said that they could not prepare for their old age due to lack of social programs to help preparation for old age and due to spending for rearing and education of their children. In terms of perceived life in old age both middle-aged and old-aged generations tended to be slightly positive, but the degree of positiveness differed between respondents from urban area and those from rural area regardless of generations. Images of the aged were perceived to be overwhelmingly negative while positive images were very few in number regardless of generations. This finding may suggests that negative stereotypes on aging and the aged are also prevalent in Korean society like in Western societies. Based on findings of this study some implications for social policies in response to population aging in capital region were suggested.