• Journal of Preventive Medicine and Public Health
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• v.28 no.1 s.49
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• pp.103-121
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• 1995

An investigation on psychophysiological health and social well-being of shift workers been carried out on workers of a automobile manufacturing plant in Ulsan, for 1 month from April, 1993. This cross-sectional survey compared shift workers(n=544) with day workers(n=115). Each subject completed a questionnaire about his personal habit, background, shift schedule, sleep and eating patterns, subjective digestive symptom and psychological well-being and distress using the General Well-Being Schedule(GWB) by self administrated questionnaire that was developed for the U.S. Health and Nutrition Examination Surveys (HANES I). Chi-square analysis was used for discontinuous data and the t-test was used for continous data to determine whether differences noted between the two groups. In terms of sleep quality, a greater percentage of shift workers frequently had trouble getting back to sleep once awakend(p<0.01), and a greater percentage of shift workers awakend tired or sleepy frequently more often than day workers(p<0.05). In rating the quality of their sleep, more shift workers rated their sleep fair to poor than day workers, and greater percentage of shift workers felt tired or sleepy at work two or more times per week(p<0.01) and a much higher percentage of shift workers felt tired or sleepy after work every days(p<0.01). In terms of sleep patterns, a much higher percentage of day workers reported uninterrupted sleep per 24hours than shift workers. The shift workers reported different eating patterns from day workers but there were no statistically significant and rate of their appetite. Thirteen percent of day workers reported the best appetite but only 6.6% of shift workers had the best appetite. The gastric complaints is more frequent in shift workers than day workers(p<0.01). Among subscores in General Well-Being Schedule, anxiety, depression, positive well-being and vitality subscale of shift workers were lower than those of day workers(p<0.05) and general health and self control subscale of shift workers were lower than .those of day workers but there were no statistical significant difference. Based on these study result, it could be concluded that the shift work has significant effects on some psychophysiological conditions of the workers.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.4
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• pp.307-327
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• 2008

Geochemical study on the rocks and minerals of the Gyeongju low and intermediate level waste repository was carried out in order to provide geochemical data for the safety assessment and geochemical modeling. Polarized microscopy, X-ray diffraction method, chemical analysis for the major and trace elements, scanning electron microscopy(SEM), and stable isotope analysis were applied. Fracture zones are locally developed with various degrees of alteration in the study area. The study area is mainly composed of granodiorite and diorite and their relation is gradational in the field. However, they could be easily distinguished by their chemical property. The granodiorite showed higher $SiO_2$ content and lower MgO and $Fe_2O_3$ contents than the diorite. Variation trends of the major elements of the granodiorite and diorite were plotted on the same line according to the increase of $SiO_2$ content suggesting that they were differentiated from the same magma. Spatial distribution of the various elements showed that the diorite region had lower $SiO_2,\;Al_2O_3,\;Na_2O\;and\;K_2O$ contents, and higher CaO, $Fe_2O_3$ contents than the granodiorite region. Especially, because the differences in the CaO and $Na_2O$ distribution were most distinct and their trends were reciprocal, the chemical variation of the plagioclase of the granitic rocks was the main parameter of the chemical variation of the host rocks in the study area. Identified fracture-filling minerals from the drill core were montmorillonite, zeolite minerals, chlorite, illite, calcite and pyrite. Especially pyrite and laumontite, which are known as indicating minerals of hydrothermal alteration, were widely distributed in the study area indicating that the study area was affected by mineralization and/or hydrothermal alteration. Sulfur isotope analysis for the pyrite and oxygen-hydrogen stable isotope analysis for the clay minerals indicated that they were originated from the magma. Therefore, it is considered that the fracture-filling minerals from the study area were affected by the hydrothermal solution as well as the simply water-rock interaction.

• The Korean Journal of Pesticide Science
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• v.11 no.2
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• pp.95-105
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• 2007

The aim of this study was to determine the residual amounts of PAHs in environmental samples such as crop, soil and water collected from paddy, upland fields and forestlands near industrial zone and/or a thermal power plant in South Korea. All of the samples were analyzed by GC-mass spectrometer. The average contents of total PAHs in soil samples were 140.2 ${\mu}g\;kg^{-1}$ and the range was from 4.3 to $662.9{\mu}g\;kg^{-1}$. The detection of benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene and dibenzo(a,h) anthracene which have strong carcinogenecity was ranged from 14.2 to 167.8 ${\mu}g\;kg^{-1}$. The residual amounts and detection frequency of PAHs in soil samples from the iron and heavy industrial areas near Pohang and Busan were 3-folds more than those of the other areas. Amounts of PAHs in upland soil samples was 1.5 folds higher than those of paddy soil samples, suggesting that it may be related to the content of organic matter in soil. The average contents of total PAHs in crop samples were 9.7 ${\mu}g\;kg^{-1}$ which ranged from 4.5 to 52.2 ${\mu}g\;kg^{-1}$. However, the residual amounts of PAHs in water samples were not detected. These results showed that soils and crops were slightly contaminated with PAHs. Therefore, the investigation should be continued for evaluating a safety or risk assessment through expansion of regions and crops.

• Journal of Technologic Dentistry
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• v.33 no.1
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• pp.93-102
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• 2011

Purpose: The study aimed to evaluate working environment for dental technician by measuring dust level, ventilation conditions and the use of personal protective equipment and to provide basic information required to improve working environment and develop health education programs for dental technician. Methods: A total of 240 dental technician who are registered with the Daegu Association of Dental technician and working at 34 dental laboratories participated in the study. And the dust level was measured at 21 different spots in 16 dental laboratories out of 34. Results: Of 34 dental laboratories, 31 (91.2%) were equipped with a ventilator, but the remaining 3 (8.8%) did not have a ventilator. By the number of ventilator, 1 to 3 ventilators were found in 22 dental laboratories (71.0%), 4 to 6 ventilators were in 7 laboratories (22.5%) and more than 7 ventilators in 2 laboratories(6.5%). According to the frequence of changing filters in dust collector, 20 dental laboratories (58.9%) changed filters every four weeks, 10 laboratories (29.4%) changed them every six weeks and 4 laboratories (11.7%) changed them every eight weeks. Of total respondents, 114 (61.3%) said they wore a mask all the time while working, 56 (29.6%) said they frequently wore a mask, 19 (10.1%) said they did not wear a mask. As for the type of masks, 159 (84.1%) used a disposable mask, 25 (13.2%) used a cotton mask and 5 (2.7%) used an anti-dust mask. For dust sat on their outfits while working, 102 (54.0%) shook their uniforms inside workplace to keep dust off the uniforms, 64 (33.9%) did not anything until they wash their uniforms and 23 (12.1%) shook their uniforms outside workplace to keep dust off the uniforms. Of total respondents, 182 (96.3%) had a particle in their eyes while carrying out grinding work. Based on the measurement of floating dust at workplace, 3 dental laboratories showed dust concentration exceeding the minimum level of 10 mg/$m^3$ allowed under the permit for environment. Of those, 1 laboratory had the dust concentration that was more than 1.5 times higher than the minimum level. Dust concentration was higher in laboratories that used a dust collector with 0.5 horse power and changed filters more than 3 weeks ago. Dust comprised of nickel (more than 70%), chrome (9%) and others. The mean chrome concentration was more than twice higher than the minimum permissible level of 0.5 mg/$m^3$. There were two laboratories that showed chrome concentration exceeding the level of 0.4 mg/$m^3$. Like dust concentration, chrome level was higher in laboratories that used a dust collector with 0.5 horse power and changed filters more than 3 weeks ago. There were six laboratories that had nickel concentration exceeding the minimum permissible level of 1 mg/$m^3$. Of those, one laboratory had nickel concentration that was more than three times higher than the minimum permissible level. Nickel concentration was also higher in laboratories that used a dust collector with 0.5 horse power and changed filters more than 3 weeks ago. Conclusion: It is not likely that heavy metal concentrations found in the study constitute respiratory dust. It is however necessary for health of dental technician to apply the Industrial Safety and Healthy Law to dental laboratories and make recommendations for the use of personal protective equipment, installation of a proper number of ventilators, more frequent change of filters in dust collector and improved ventilation for polishing work. At the same time, dental technician need education on how to use personal protective equipment and how to efficiently remove dust from their uniforms.

• Journal of Radiation Protection and Research
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• v.40 no.2
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• pp.118-123
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• 2015

The frequency of diagnostic radiation examinations in medical institutions has recently increased to 220 million cases in 2011, and the annual exposure dose per capita was 1.4 mSv, 51% and 35% respectively, compared to those in 2007. The number of chest radiography was found to be 27.59% of them, the highest frequency of normal radiography. In this study, we developed a shielding device to minimize radiation exposure by shielding areas of the body which are unnecessary for image interpretation, during the chest radiography. And in order to verify its usefulness, we also measured the difference in entrance surface dose (ESD) and the absorbed dose, before and after using the device, by using an international standard pediatric (10 years) phantom and a glass dosimeter. In addition, we calculated the effective dose by using a Monte Carlo simulation-based program (PCXMC 2.0.1) and evaluated the reduction ratio indirectly by comparing lifetime attributable risk of cancer incidence (LAR). When using the protective device, the ESD decreased by 86.36% on average, nasal cavity $0.55{\mu}Sv$ (74.06%), thyroid $1.43{\mu}Sv$ (95.15%), oesophagus $6.35{\mu}Sv$ (78.42%) respectively, and the depth dose decreased by 72.30% on average, the cervical spine(upper spine) $1.23{\mu}Sv$ (89.73%), salivary gland $0.5{\mu}Sv$ (92.31%), oesophagus $3.85{\mu}Sv$ (59.39%), thyroid $2.02{\mu}Sv$ (73.53%), thoracic vertebrae(middle spine) $5.68{\mu}Sv$ (54.01%) respectively, so that we could verify the usefulness of the shielding mechanism. In addition, the effective dose decreased by 11.76% from $8.33{\mu}Sv$ to $7.35{\mu}Sv$ before and after wearing the device, and in LAR assessment, we found that thyroid cancer decreased to male 0.14 people (95.12%) and female 0.77 people (95.16%) per one million 10-year old children, and general cancers decreased to male 0.14 people (11.70%) and female 0.25 people (11.70%). Although diagnostic radiation examinations are necessary for healthcare such as the treatment of diseases, based on the ALARA concept, we should strive to optimize medical radiation by using this shielding device actively in the areas of the body unnecessary for the diagnosis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.3
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• pp.379-389
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• 2008

This study was conducted to assess the microbiological quality of raw and cooked foods served in the elementary school food service. Raw and cooked food samples were collected from 11 selected elementary schools in both June to July and September to October of 2005. Petrifilm plates were used to determine (in duplicate) total aerobic colony counts (PAC), Enterobacteriaceae (PE), coliform counts (PCC), and E. coli counts (PEC). Heavy contamination of Enterobacteriaceae (from 0.08 to 7.40 log CFU/g) and total coliform (0.50 to 6.52 log CFU/g) were observed in raw materials and cooked foods. Escherichia coli (E. coli) were detected in the sample of currant tomato (3.70 log CFU/g), sesame leaf (3.59 log CFU/g), dropwort (0.20 log CFU/g), crown daisy (3.15 log CFU/g), parsley (3.00 log CFU/g), peeled green onion (1.74 log CFU/g), frozen pork (0.65 log CFU/g), frozen beef (0.20 or 1.50 log CFU/g), chicken (1.78 log CFU/g), and young radish leaf seasoned with soybean paste (1.24 log CFU/g). Multiplex PCR system was used to determine the food-borne pathogens: Salmonella spp., Bacillus cereus (B. cereus), E. coli O157:H7, Staphylococcus aureus, Listeria monocytogenes (L. monocytogenes), Vibrio parahaemolyticus, Campylobacter jejuni (C. jejuni), Shigella spp., B. cereus was detected in 19 samples of raw materials and 8 samples of cooked foods. With regard to quantitative analysis, B. cereus counts exceeded 5.46, 3.48 and 1.79 log CFU/g in sesame leaf, peeled green onion and seasoned mungbean jelly, respectively. E. coli O157:H7 was detected on 2 samples of frozen beefs, and its biochemical characteristics of one beef sample was confirmed with API 20E kit (93.7%). L. monocytogenes was detected in fried rice paper dumpling, but the presumptive colonies were not detected onto the conventional plate. C. jejuni was detected in peeled & washed onion.

• Korean Journal of Food Science and Technology
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• v.42 no.6
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• pp.762-767
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• 2010

This study evaluated daily intakes of BHT, BHA, and TBHQ in Korean. The daily intakes were estimated using both a dietary survey approach and food supply survey approach. In the dietary survey approach, individual dietary intake data from the Korea National Health and Nutrition Survey in 2005, as well as analytical results of BHT in 131 samples, BHA in 134 samples, and TBHQ in 104 samples, were used to assess daily intakes of the antioxidants. In the food supply survey approach, both total production amounts of BHT, BHA and TBHQ and maximum permitted levels of the antioxidants were used to calculate daily intakes. In the dietary survey results, the average daily intakes of BHT, BHA and TBHQ were 0.8, 0.5, and 0.3 ${\mu}g$/kg body weight/day, respectively, and below 0.2% of the ADI (acceptable daily intake) set by JECFA (Joint FAO/WHO Expert committee on Food Additives). In the food supply survey approach, the average daily intakes of BHT, BHA,and TBHQ were all 0.3 mg/kg body weight/day. The ratios of ADI were 97, 60, and 40%, respectively. According to these results, daily intakes of BHT, BHA, and TBHQ in Korean are lower than the ADI.

• Korean Security Journal
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• no.29
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• pp.163-191
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• 2011

Recently, the problems in school violence did not stop on the crime between the members at the school and which developed into the invasion crime of the school caused by outsiders. The school is no more the safety zone from the crime. Particularly, in the case of the elementary school, because there are nearly no people who oppose to the outside attacker and can control this, it is the place where it is vulnerable to the invasion crime. The Metropolis of Seoul implements the School Sheriff system within the jurisdiction bureau, in the public elementary school. However, actually the School Sheriff business is being managed, never applying a rule in the Security Industry Law with the main content, that is the Security Industry Law application is excluded. Because the jurisdiction on the contract of Seoul City and operating company are run, the various issues is caused. First, since it is not being considered as a security business, the commercial liability insurance for security company has no chance to applicate when the operation company and the School Sheriff have related damage generation. So the security for the indemnification of loss of the victim is weak. Second, The task of the School Sheriff is ruled just by in the individual contracts. But it is insufficient with this thing. The related duties are required some supplement like a general rule application including the obligation of the guard in the security industry law. Third, the education of the School Sheriff needs to connect with the educational programme in the security industry law. The related professional education specially needed for the prevention of school violence ought to be reserved compensation. Forth, the citizens still demand the strengthening of police patrol for the surroundings of a school in spite of the result of Seoul City's public survey. Therefore, the active relation of cooperation with the police needs to be supported legally and institutionally with the Security Industry Law application. Fifthly, the success of the School Sheriff business can be more guaranteed with the supervision of the legal and institutional device like a the Security Industry Law application or police and all sorts of administrative execution's and etc.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.399-407
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• 2009

Laser induced breakdown spectroscopy(LIBS) is an simple analysis method for directly quantifying many kinds of soil micro-elements on site using a small size of laser without pre-treatment at any property of materials(solid, liquid and gas). The purpose of this study were to find an optimum condition of the LIBS measurement including wavelengths for quantifying soil elements, to relate spectral properties to the concentration of soil elements using LIBS as a simultaneous un-breakdown quantitative analysis technology, which can be applied for the safety assessment of agricultural products and precision agriculture, and to compare the results with a standardized chemical analysis method. Soil samples classified as fine-silty, mixed, thermic Typic Hapludalf(Memphis series) from grassland and uplands in Tennessee, USA were collected, crushed, and prepared for further analysis or LIBS measurement. The samples were measured using LIBS ranged from 200 to 600 nm(0.03 nm interval) with a Nd:YAG laser at 532 nm, with a beam energy of 25 mJ per pulse, a pulse width of 5 ns, and a repetition rate of 10 Hz. The optimum wavelength(${\lambda}nm$) of LIBS for estimating soil and plant elements were 308.2 nm for Al, 428.3 nm for Ca, 247.8 nm for T-C, 438.3 nm for Fe, 766.5 nm for K, 85.2 nm for Mg, 330.2 nm for Na, 213.6 nm for P, 180.7 nm for S, 288.2 nm for Si, and 351.9 nm for Ti, respectively. Coefficients of determination($r^2$) of calibration curve using standard reference soil samples for each element from LIBS measurement were ranged from 0.863 to 0.977. In comparison with ICP-AES(Inductively coupled plasma atomic emission spectroscopy) measurement, measurement error in terms of relative standard error were calculated. Silicon dioxide(SiO2) concentration estimated from two methods showed good agreement with -3.5% of relative standard error. The relative standard errors for the other elements were high. It implies that the prediction accuracy is low which might be caused by matrix effect such as particle size and constituent of soils. It is necessary to enhance the measurement and prediction accuracy of LIBS by improving pretreatment process, standard reference soil samples, and measurement method for a reliable quantification method.

• Journal of Nutrition and Health
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• v.52 no.2
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• pp.227-241
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• 2019

Purpose: This study examined the relationship between caffeine intake and metabolic syndrome in Korean adults using the 2013 ~ 2016 Korea National Health and Nutrition Examination Survey data (KNHANES). Methods: The caffeine database (DB) developed by Food and Drug Safety Assessment Agency in 2014 was used to estimate the caffeine consumption. The food and beverage consumption of the 24 hr recall data of 2013 ~ 2016 KNHANES were matched to items in the caffeine DB and the daily caffeine intakes of the individuals were calculated. The sample was limited to non-pregnant healthy adults aged 19 years and older, who were not taking any medication for disease treatment. Results: The average daily caffeine intake was 41.97 mg, and the daily intake of caffeine of 97% of the participants was from coffee, teas, soft drinks, and other beverages. Multivariate analysis showed that the caffeine intake did not affect metabolic syndrome, hypertension, low HDL-cholesterol, and abdominal obesity. Diabetes and hypertriglyceridemia, however, were 0.76 (95% CI: 0.63 ~ 0.93), and 0.87 (95% CI: 0.77 ~ 0.98) in third quintile (Q3), and 0.66 (95% CI: 0.53 ~ 0.82) and 0.83 (95% CI: 0.73 ~ 0.94) in fourth quintile (Q4) compared to Q1, respectively. Therefore, caffeine intake of 3.66 ~ 45.81 mg per day is related to a lower risk of diabetes and hypertriglyceridemia. Conclusion: The study showed that adequate caffeine intake (approximately 45 mg) was associated with a lower prevalence of diabetes and hypertriglyceridemia. Therefore, it can be used as a guideline for the adequate level of caffeine intake for maintaining health.