• Journal of radiological science and technology
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• v.34 no.1
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• pp.17-25
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• 2011

In this study, we examined the impact caused by chronic exposure to Mn by investigating the degree of brain activation based on the data of recognition activities using fMRI (functional magnetic resonance imaging). A questionnaire survey, blood tests, and fMRI tests were carried out with respect to two groups. Group 1 was an exposure group consisting of 15 male workers who are 34 years old or older, and who worked for longer than 10 years in a shipbuilding factory as a welder. Group 2 was a control group consisting of 15 workers in manufacturing industries with the same gender and age. The results showed that blood Mn concentration of Group 1($1.3\;{\mu}g/dl$) was significantly higher than that of Group 2($0.8\;{\mu}g/dl$)(p < 0.001), and Pallidal Index (PI) of Group 1 was also significantly higher than that of Group 2 (p < 0.001). PI value of the group whose blood Mn concentration was $0.93\;{\mu}g/dl$ or higher was significantly higher than that of the group whose blood Mn concentration was less than $0.93 \;{\mu}g/dl$ (p < 0.001). As for brain activity area within the control group, the right and the left areas of occipital cortex showed significant activity and the left area of middle temporal cortex, the right area of superior inferior frontal cortex and inferior parietal cortex showed significant activity. Unlike the control group, the exposure group showed significant activity on the right area of superior inferior temporal cortex, the left of insula area. In the comparison of brain activity areas between the two groups, the exposure group showed significantly higher activation than the control group in such areas as the right inferior temporal cortex, the left area of superior parietal cortex and occipital cortex, and cerebellum including middle temporal cortex. However, in nowhere the control group showed more activated area than the exposure group. As the final outcome, chronic exposure to Mn increased brain activity during implementation of arithmetic task. In an identical task, activation increased in superior inferior temporal cortex, and insula area. And it was discovered that brain activity increase in temporal area and occipital area was more pronounced in the exposure group than in the control group. This result suggests that chronic exposure to Mn in the work environment affects brain activation neuro-network.

• Korean Journal of Health Education and Promotion
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• v.1 no.1
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• pp.57-71
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• 1983

Sex education is necessary for the youth that they should have an adequate sexual knowledge, attitudes and behaviors in their adolescent period. Four major objectives of this study are as follows; 1. To know the level of sexual knowledge of commercial girl's high school students in Seoul. 2. To know their actual state for the attitudes and behaviors toward sex. 3. To compare the sexual knowledge, attitudes and behaviors of day time school students with those of night time school students. 4. To compare the factors associated with their sexual knowledge, attitudes and behaviors with the individual level. Data were collected on 986 students in Seoul from April 1 to April 10, 1983. As the result of this survey, the following conclusions were obtained. 1. The level of sexual knowledge. (1) The level of knowledge of day time high school students about the physiology of female and pregnancy is shown higher than those of night time students. 64.2% of the respondents are aware of the organ producing ovum. 56.4% the ovulation period. 95.6% the cause of pregnancy. 74.5% the pregnantable period and 12.7% the place of fetilization. (2) Out of 986 respondents. 71.8% knew about contraceptive method correctly, and day time school students knew litter better than night time school students, by showing 73.9% and 69.7% respectively. They knew about contraceptive method with 'oral pills'. 'menstrual cycles', 'condoms'. and 'loops' in the same order. 3) Kinds of veneral disease was correctly known by 37.9%. Day time students knew much better than night time school students. by showing 67.8% and 7.9%. respectively. Transmission method of veneral disease was correctly known by 28.3%. Day time students knew much better than night time students, by showing 51.2% and 5.3%, respectively. (4) The major information source of sexual knowledge was 'book and magazine' (39.9%) and 'friends' (27.4%). 2. Actual state of attitudes and behaviors toward sex. (1) Out of 986 respondents, 84.0% answered that premarital purity should be kept. (2) Out of 986 respondents, 60.8% had an acquaintance of the opposite sex. 45.2% of students with opposite sex reported introduction of their friends as the main channel of making an acquaintance of the opposite sex. (3) Of those who responded to this study 13.8% reported having masturbation, 21.5% kissing, 6.2% petting and 3.7% sex intercourse. (4) 64.8% had sexual problems, which was mensturance (27.2%), aquaintance of the opposite sex (25.4%). The main method to solve the problems were consultation with 'friends' and 'books and magazine' percentage being 39.1% and 30.8%, respectively, whereas very small students discussed with 'teachers' and 'parents' percentages being 0.3% and 5.9%, respectively. (5) Out of 986 respondents, 62.2% had experience in educating about sex, the percentage of day time school was higher than that of night time school. (6) 88.2% of students wanted sex education in school, which were 'general information about sex' (35.4%), 'sexual morality and solution of sexual desire' (18.5%), 'aquaintance of the opposite sex' (13.3%) and 'marriage and role of man and woman' (12.4%) in the same order. They wanted to be instructed about sexes in the lecture of physical education, home economics, biology, military training (59.9%), regular curriculum (17.5%), special lecture (16.9%) and by the counselor or school nurse (5.7%). 3. Analyse concerning the factors about the knowledge, attitudes and behaviors. (1) The better school record was, the higher the level of sexual knowledge. (2) Those who have the religion considered the permarital purity more important than those who have not, the percentage showing 86.7% and 80.7%, respectively. (3) The result of dyad analysis of making acquaintance of the opposite sex in the friendship network showed that a high index of the acquaintance of the opposite sex tends to be a high adoption of making one at the individual level in the group, while the low index tends to be a low adoption of making one in the group.

• Sleep Medicine and Psychophysiology
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• v.20 no.2
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• pp.69-74
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• 2013

Introduction: Although it is well known that medical students are not getting an adequate amount of sleep, there have been only a few studies on the sleep patterns of medical students and the related factors. Therefore, the present study aimed to investigate the medical students' sleep patterns and the related factors. Methods: A questionnaire package was administered to the $1^{st}$ to $4^{th}$ year medical students at one medical school. It consisted of questions asking about their lifestyles as well as Pittsburgh sleep quality index (PSQI), Epworth sleepiness scale (ESS), global assessment of recent stress scale (GASS), the center for epidemiologic studies-depression scale (CES-D), and Moudsley obsessive-compulsive inventory (MOCI). A total of 352 students (206 males and 146 females) responded to the survey and the result was analyzed using the independent t-test, the chi-square test, the paired t-test, Pearson's correlation and ANOVA. p-values of less than 0.05 were considered statistically significant in analyses. Results: The weekend bedtime was significantly delayed (0 : 49 on weekday ; 1 : 34 on weekend ; t=-5.23, p<0.001), the weekend rise time was delayed (6 : 58 on weekday ; 9 : 30 on weekend ; t=-24.48, p<0.001) and the total sleep time was increased on weekends (5 : 36 on weekday ; 7 : 39 on weekend ; t=15.94, p<0.001). The PSQI score of all subjects was 6.43{\pm}2.64. PSQI was positively correlated with ESS (r=0.383, p<0.001), GASS (r=0.326, p<0.001), CES-D (r=0.393, p< 0.001), and MOCI (r=0.247, p<0.001), but not with GPA (r=0.072, p=0.228. The more senior students had lower PSQI, GASS, CES-D, and MOCI score (p<0.05). Conclusion: Medical students were experiencing a lack of sleep during weekdays as they have a later bedtime and earlier rise time, and consequently had more hours of sleep on weekends. Overall, the medical students were experiencing poor sleep quality and sleep deprivation. Poor sleep quality is associated with psychological problems (daytime sleepiness, stress, depression, and obsessive tendency).

• The Korean Journal of Malacology
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• v.29 no.1
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• pp.51-63
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• 2013

To assess the effect of environmental factors on the sustainability of cultured production shellfish, we investigated the habitat characteristics of tidal flat (Namhae-po in Taean). We measured the physiochemical parameters (temperature, salanity, pH, dissolved oxygen and nutrients) and the geochemical characteristics (chemical oxygen demand, ignition loss, C/N ratio and C/S ratio). Surface sediments were collected from several site of tidal flat to examine the geochemical characteristics of both the benthic environment and heavy metal pollution. The grain size for research area of tidal flat were similar at the ratio of silt and clay in comparison with the other site of it. The C/N ratio was more than 5.0, reflecting the range arising from the mix of marine organism and organic matter. The C/S ratio (about 2.8) showed that survey area had anoxic or sub-anoxic bottom conditions. The enrichment factor (Ef) and index of accumulation rate (Igeo) of the metals showed that those research areas can be classified as heavily polluted, heavily to moderately polluted, or more or less unpolluted, respectively. Adult surf clam (Mactra veneriformis) density was highest at St. 2 (middle part of the Namhae-po), on the other hand, surf clam spat density was highest at St. 3 (lower part of the Namhae-po). Heavy rain, terrigenous suspended clay with fresh water from neighboring agricultural land, and severe high air temperature during summer could be thought as detrimental causes of spat and adult mortality in Namhae-po tidal flat. We suggested that the growth of shellfish in the tidal flat was effected by the various environmental conditions, so an improvement in the cultured method was needed.

• Journal of dental hygiene science
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• v.13 no.3
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• pp.254-263
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• 2013

This study is to develop an evaluation index for infection control and to verify its validity by examining each set of weighted data collected from 121 infection control personnel at dental hospitals who agreed to the preliminary survey and advisory. The study was conducted from 14th December, 2010 to 31st January, 2011, and PASW Statistics 18.0 and AMOS 5.0 had been used for the statistical data analysis. As a result of the study, five evaluation factors with 21 sub-indicators have been identified at structural level, eight evaluation factors with 32 sub-indicators at processing level, and one evaluation fact with five sub-indicators at resulting level, total 14 evaluation factors with 58 sub-indicators throughout all levels. The path analysis added on the result that 'standard precautions ($x_1$)', 'infection control support system ($x_2$)', 'internal and external characteristics ($x_3$)' are exogenous variables that affect on other variables, and 'standard infection control ($y_1$)','Organization equipment management handwashing ($y_2$)', 'environmental infection control ($y_3$), 'personal protective equipment ($y_4$)', 'waste and laundry management ($y_5$)' are endogenous variables that are infulenced by others. The standardized metrics are more needed than anything else when examining on infection control. This study attempts to develop proper dental infection control metrics adequately adjusted for domestic circumstances, and therefore to contribute to effective systematic management and decision-making in infection control.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.4
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• pp.457-467
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• 2012

Purpose: This study was performed to investigate the relationship between ocular and allergy symptoms in children by environmental pollutants emitted from new constructed building. Methods: Two different types of survey (6-Item Dry Eye Questionnaire and Ocular Surface Disease Index) were used to study dry eye syndromes and ocular subjective symptoms for a six-grade of elementary school students (54 males and 61 females) in newly built buildings in the past three month, located near capital city, Seoul. Atopy and medical history of allergic rhinitis were investigated with using questionnaire for allergy, and also nose itchiness and ocular symptoms were checked as visual analog scale(10-score) with using questionnaire of allergy rhinitis and conjunctivitis under the guideline of ARIA(Allergic Rhinitis Impacts on Asthma). Results: Fifty seven students (50%) from DEQ and 19 students (16.52%) from OSDI were diagnosed as dry eye, and 18 students (15.79%) were diagnosed as dry eye from both questionnaires. It was surveyed that 45 students (39.5%) and 29 students (25.4%) had atopy and allergy rhinitis, respectively. Among 45 students having atopy, 30 students and 8 students were diagnosed as dry eye with using DEQ and OSDI, respectively. And also, 22 students were diagnosed as dry eye by DEQ and 5 students were diagnosed as dry eye by OSDI from 29 students having allergy rhinitis. Among 29 students having both medical history atopy and allergy rhinitis, 15 students detected observable ocular symptom. The complicating allergy symptoms with ocular syndrome were arranged with sneeze, nose itchiness, nose stuffiness, and runny nose in order of frequency. As students recognized eye symptoms, the number of allergy found and student's number were increased proportionally. Conclusions: It was found that children's subjective ocular symptoms were confirmed in the environment as newly built building. The number of student for dry eye was proportionally increased to students having atopy and allergy symptoms.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.306-314
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• 2002

The purpose of this study is to examine the relation between vegetarian diet and the risk factors of cardiovascular disease. The subjects of the study were 127 Buddhist nuns (age: 23 ~79 yr) for vegetarians and 235 healthy female adults (age: 23 ~79 yr) for non-vegetarians. This study covers food consumption survey, anthropometric measurement, amount of energy expenditure, physical activity and clinical examination. Average body mass index (BMI) of vegetarians and non-vegetarians were 22.47 and 21.08, waist/hip ratio (WHR) was 0.85 and 0.84, percentage of body fat (%BF) was 28.79 and 26.55, respectively. Average duration of vegetarian diet of the vegetarians was 13.16 years. The triglyceride levee of the vegetarians was significantly lower for those who take nutrient tablet compared to those who either take vitamins or who do not take any nutrient supplement. Taking vitamins or nutrient tablet did not give any significant difference in total-cholesterol and LDL-cholesterol for vegetarians, while significantly high triglyceride was observed for the non-vegetarians taking nutrient tablet than the ether non-vegetarians. Taking vitamins or nutrient tablet did not affect the lever of HDL-cholesterol for either vegetarians or non-vegetarians. Athrogenic index (AI) was lower for the vegetarian group tailing nutrient tablet and for the non-vegetarian group not taking vitamins and nutrient tablet, than the other respective groups. Blood sugar of the vegetarians who take nutrient tablet was significantly lower than those tailing vitamins, while blood sugar of the non-vegetarians not taking any nutrient supplement was significantly lower than those taking nutrient tablet.

• Korean Journal of Ichthyology
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• v.25 no.2
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• pp.90-105
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• 2013

This study was performed to find out stomach contents of cold water fish such as Manchurian trout (Brachymystax lenok tsinlingensis) and River salmon (Oncorhynchus masou masou) in the Odae mountain area. Field survey was carried out 3 times by each season from May to October 2012 along the Gyebang stream and the Yangyang-Namdae stream at north-west mountain slope and north-east mountain slope of the Odae mountain area respectively. The result of digestive track analysis showed that food species of Manchurian trout were total individuals of 645 including 5 orders, 23 families, 39 species of benthic macroinvertebrates and 11 taxa of terrestial insects. And each IRI (Index of Relative Importance, %) value of food species by Manchurian trout was terrestial insects 37.0%, Trichoptera 36.4%, Ephemeroptera 20.0%, Diptera 3.9%, Plecoptera 2.7%, and Gordea <0.1%. While the River salmon fed on 1,186 individuals covering 4 orders, 20 families, 33 species of benthic macroinvertebrates and 6 taxa of terrestial insects including arachnid. Also IRI values by River salmon were terrestial insects including arachnid 2.7%, Ephemeroptera 52.9%, Trichoptera 27.9%, Diptera 9.4%, and Plecoptera 7.0% respectively. With these results, we might say that both Manchurian trout and River salmon is carnivorous fish which display the feeding preference to terrestial insects and benthic macroinvertebrates. As a results we could find out that the two kinds of cold water fish preferred similar habitat types and liked same order of food species in same season, however the compositions of food species for Manchurian trout and River salmon were considerably different.

• Korean Journal of Environment and Ecology
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• v.27 no.5
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• pp.579-591
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• 2013

This study was carried out to investigate the actual vegetation, the structure of plant community, and ecological succession sere of forest ecosystem in temperate northern climate zone, Daegwallyeong Ranch, Gangwon-do (Province) and to offer the basic data for planning of the forest managemant. As a result of analysis of actual vegetation, vegetation types divided into 56types and the area of survey site was $19,397,361m^2$. The ratio of vegetation type dominated by Quercus mongolica forest was 39.1%, primary grassland was 24.7%, Quercus mongolica-Deciduous broad-leaved forest was 11.3%. Twenty eight plots (size is $20m{\times}20m$) were set up and the results analyzed by DCA which in one of the ordination technique showed that the plant communities were divided into six groups which area community I (Pinus densiflora-Quercus mongolica community), community II (Quercus mongolica-Pinus densiflora community), community III (Quercus mongolica community), community IV (Quercus mongolica-Deciduous broad-leaved community), community V (Deciduous broad-leaved community), community VI (Sorbus alnifolia community). The age of community Iwas ranged from 57 to 62 years old, that of community IIwas ranged from 41 to 77 years old, community III was ranged from 47 to 108 years old, community IV was ranged from 47 to 82 years old, community V was 47 years old, community VI was 55 years old, thus we supposed that the age of the study site is about from 41 to 108 years old. The Ecological succession is predicted from Pinus densiflora community to Quercus mongolica community and Deciduous broad-leaved were distributed in the center of the valley in Daegwallyeong Ranch. According to the index of Shannon's diversity (unit: $400m^2$), community IV was ranged from 0.8203 to 1.1439, community III was ranged from 0.8019 to 1.1375, community V was 1.0993, community I was ranged from 0.9475 to 1.0797, community II was ranged from 0.6896 to 1.0324, community VI was 0.9909.

• Journal of dental hygiene science
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• v.4 no.3
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• pp.91-95
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• 2004

This study aims to analyze realities of oral health and related factors, and establish Structural Equation Modeling. The subjects of study were 9,340 elderly over age 65 who took the health examination(the first) for the local insured which National Health Insurance Corporation carried out in the survey area mentioned below from January 2002 to December 2002. The areas surveyed were 4 big cities including Seongbuk-ku, Seoul, 5 medium cities including Wonjusi, Gangwon-do, and 5 Counties including Yeong deok County, Kyeongbuk. Considering location and the scale of population, firstly, big unit areas(metropolitan city, province) were selected according to convenience, secondly, low unit areas(city, county, district) were selected randomly. The subjects were the elderly who took all tests including an oral examination and filled in the questionnaire. Major results from analysis are as follows: 1. Review of Composition Conception Validity As a result of analyzing composition conception validity of SEM including posture test, urine test, blood test, habits of eating, drinking and smoking, oral symptoms, and oral health status, using fit index such as GFI, CFI, TLI, and RMSEA, all were within fit range and composition conception validity was recognized. 2. As a result of analyzing SEM to find the relationship between each factor and oral health status, it was confirmed that all factors except urine test affected oral health status and the synthetic SEM to explain it could be established. In result, we could verify that the elderly of rural areas who had lesser experience of visiting a clinic and oral prophylaxis had a higher rate of caries, missing teeth, and denture need, and drinking and smoking negatively affected the rate of caries, periodontal, and missing teeth. Also, periodontal diseases were observed from 43.2% of the total elderly and much from the lower age. Most of oral disease can be prevented by right oral health behavior. Therefore through oral health professionals from each district public health center of the nation, oral health education for the elderly about right eating habits and oral health care should be carried out systematically and policy change to increase access to dental service is required lest that visiting a dental clinic should be impossible or oral health behaviors such as oral prophylaxis and denture wearing should be neglected by economic, geographical barriers. Also, to establish SEM to explain the relationship between oral health status and systemic health, more accurate test methods and effective index development should be preceded. Because items developed by National Health Insurance Corporation applied to this study without alteration, structuring a model had the uppermost limit. Continual study seems to be needed.