• Journal of dental hygiene science
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• v.4 no.1
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• pp.7-11
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• 2004

The purpose of this study was to investigate the distribution of microorganisms and the degree of contamination in the air of the dental clinics and to offer basic data as to the contamination of medical equipment and the prevention of the clinics. With this in mind, the researcher gathered air samples from the waiting rooms and medical offices of nine dental clinics in the city of J, South Korea with the use of a method of natural inattention and an air sampler and cultivated the samples on the plain table and drew from it bacteria falling and separated and sorted out the colony with the help of ATB and detected the distribution of the germs. The results are following, The number of bacteria falling in the air of the dental clinics was less than 10(CFU/Plate) with the exception of one dental clinic. This implies that they fit in with standards for hygiene. The number of bacteria falling in the air of the medical offices was less than 10(CFU/Plate) with the exception of one dental clinic. This implies that they fit in with standards for hygiene. The survey on the detection of staph. aureus reveals that all the dental clinics with the exception of B dental clinic proving to be positive had non-pathogenic staphylococci detected. The survey on the detection of pathogenic gram negative bacilli indicates that all the dental clinics but one were none detected. The survey on the distribution of germs shows that germs in 7 out of 9 dental clinics were none detected, and that they in four out of 9 waiting rooms were none detected. All the germs detected in the others were mostly non-pathogenic. The study shows that all the subject dental clinics but one were hygienically controlled and that there was a difference in accordance with cleaning and sterilization. This means that dental clinics should be equipped with systematic programs for cleaning and sterilization designed to prevent infection.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1159-1170
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• 2000

It is necessary to improve the ambient air quality through the proper treatment and control of pollutants by designating air pollutants to regulatory ones. Especially, human took a concern for particulate matters which raised visibility reduction, public health effects and injury of property for urban areas. In order to reduce the effect of particulate matters, we need to establish proper control strategies based on the concentration characteristics of particulate matters. In this study. to evaluate the characteristics of $PM_{2.5}$ and $PM_{10}$. thirty-eight samples of $PM_{2.5}$ and $PM_{10}$ were collected at Nam-Gu sampling site where continuous air monitoring system has been operated, from May, 1999 to November, 1999, and their concentrations for the mass and anion components($Cl^-$, $NO_3{^-}$, $SO_4{^{2-}}$) were analyzed. The important conclusions obtained in this study were as followings. Total average mass concentrations of $PM_{2.5}$ and $PM_{10}$ were 35.016 and $50.293{\mu}g/m^3$ respectively. and $PM_{2.5}/PM_{10}$ ratio was calculated 0.692. Total average concentrations of anion components in $PM_{2.5}$ were $1.581(Cl^-)$, $3.690(NO_3{^-})$ and $12.825(SO_4{^{2-}}){\mu}g/m^3$ and those in $PM_{10}$ were $2.471(Cl^-)$, $5.819(NO_3{^-})$ and $14.414(SO_4{^{2-}}){\mu}g/m^3$ respectively. From the correlations analysis. the correlation coefficient between mass concentration of $PM_{2.5}$ and $PM_{10}$ was calculated as 0.945. The correlation coefficients between $PM_{2.5}$ and anion components were analyzed as $Cl^-$(0.025), $NO_3{^-}$(0.788) and $SO_4{^{2-}}$(0.500) respectively, and the correlation coefficients between $PM_{10}$ and anion components were analyzed as $Cl^-$(-0.019), $NO_3{^-}$(0.806) and $SO_4{^{2-}}$)(0.535) respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.2
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• pp.252-260
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• 2009

Whereas the numbers of childcare centers and kindergartens are increasing rapidly, systematic management to control the food safety of foodservice operation is not yet well established. Samples from 12 centers in Seoul and Gyeonggi Province were collected to assess the microbiological quality of 32 raw materials, 24 cooked foods, 76 food-contact surfaces (knives, cutting boards, dish towels and gloves), 17 employees' hands and 12 air-borne bacteria. The microbiological analyses were performed for aerobic plate counts (APC), Enterobacteriaceae, E. coli and 7 pathogens (B. cereus, C. jejuni, C. perfringens, L. monocytogenes, Salmonella spp., S. aureus, and V. parahaemolyticus). Among raw materials, E. coli ($1.39{\sim}2.08\;\log\;CFU/g$) were detected in 4 out of 6 meats and 7.46 log CFU/g of APC in tofu. High enterobacteriaceae levels of 4.23, 5.14 and 4.19 log CFU/g were found in cucumber salad, steamed spinach with seasonings and steamed bean sprout with seasonings, respectively. No pathogens were found in all samples except for C. perfringens detected from raw spinach and raw lotus root. Only APC and enterobacteriaceae were found in food-contact surfaces. Two of the 23 knives and three of the 24 kitchen boards showed over 500 CFU/$100\;cm^2$ of APC; also, APC levels (5.03 to 5.44 log CFU/g) were detected in 4 of the 12 dish towels. Only one glove showed Enterobacteriaceae (2.44 log CFU/glove) contamination. Enterobacteriaceae were found in 2 employees' hands ($2.37{\sim}4.44\;\log\;CFU$/hand) among the 16 employees. The contamination levels of air-borne bacteria were shown unacceptable in two (2.25 and 2.30 log CFU/petri-film/15 min) out of the 12 kitchen areas. These results suggest that the microbiological hazards in some foods and environments are not well controlled and thus a guideline should be provided to ensure the food safety in childcare center and kindergarten foodservice operations.

• Korean Journal of Construction Engineering and Management
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• v.1 no.3 s.3
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• pp.108-115
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• 2000

The average height of buildings in most cities is increasing in an effort to more effectively use land. In addition, as construction technology develops, rapid construction methods have been pursued. However, while there have been great strides in construction technology, the development of a temporary structure that can support the high-rise building under construction and the rapid construction methods has been relatively limited. If the temporary structure is not built on an outer wall of a building being constructed, a worker may be injured or killed in a fall and building materials such as blocks and other objects may fall to the ground, causing the build-up of trash around the building and possible injuries to persons in proximity to the building. This paper proposes a Self Climbing Safety Fence for construction building(SCfence). SCfence was developed to solve the above problems, a tent has been setup to cover the outer wall of the building, or a falling preventing net has been pitched in a direction perpendicular to the outer wall of the building. A case study was performed to verify the validity of SCfence through comparing the safety and cost experience between SCfence and the existing method.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.2
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• pp.274-282
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• 2011

The purpose of this study was to investigate factory workers' knowledge of sanitation management of school foodstuffs and sanitation practices. A questionnaire that identified employees' food safety sanitation management knowledge and practices was developed based on a review of literature. Subjects consisted of 221 factory workers employed at 34 factories in the Daegu and Gyeongbuk areas. Almost half of the factory workers were 40~49 years of age (45.7%), 34.8% had 1~3 years of work experience, 62.4% of the respondents received food safety education 1~2 times a month and 75.1% of the respondents were satisfied with sanitation education. However, the total score for factory worker sanitation knowledge was low: 4.63/9. Sanitation performance was self-evaluated using a Likert 5-point scale. The total mean score for the factory workers' sanitation performance was 4.63/5. Satisfaction level and the amount of sanitation education, application of sanitation knowledge, attitude regarding sanitation management, and sanitation management performance level were significantly high among workers employed in a HACCP certification facility (p<0.05). The difficulties were found to be sanitation management and the time to deliver food to schools. To instill a sense of duty and pride among workers and to ensure that the food suppliers provide best-quality school foodstuffs safely, school dietitians and factory managers must actively educate workers in safe food handling and sanitation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.7
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• pp.958-963
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• 2009

To improve the quality of boiled rice after storage in rice cookers, temperature was controlled at a lowered condition ($45{\sim}65^{\circ}C$ repeated temperature cycling), compared to the present commercial rice cookers ($75^{\circ}C$). The effect of lowered temperature cycling on the microbial growth, color of rice, and reducing sugar production was measured. The bacteria Bacillus cereus and B. subtilis were killed at $75^{\circ}C$ and $45{\sim}65^{\circ}C$ cycling. The temperature cycling at $45{\sim}65^{\circ}C$ prevented an increase in colony forming unit of E. coli more than the steady temperature at $75^{\circ}C$. Browning during storage was significantly decreased at $45{\sim}65^{\circ}C$ cycling, compared to $75^{\circ}C$. The yellowness increase (${\Delta}b$ value of CIE parameters of the colorimeter) after the 3-day storage was 2.18 at $45{\sim}65^{\circ}C$ cycling whereas 9.12 at $75^{\circ}C$. Reducing sugar was not produced at $75^{\circ}C$ and $45{\sim}65^{\circ}C$ cycling but produced at $30^{\circ}C$ because of the microbial growth. In conclusion, the temperature cycling at $45{\sim}65^{\circ}C$ can improve the quality of stored boiled rice by decreasing the browning and inhibiting the microbial growth.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.10
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• pp.1457-1465
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• 2009

This study was conducted to analyze the food safety management practices and to provide data that could be used to improve food safety management at kindergarten foodservice establishments in Daegu and Gyeongbuk province. Microbiological hazard analysis was conducted from May to July, 2008 at the four foodservice establishments. A total (20 items) of foodservice facilities, cooking utensils, and equipment were tested about total plate counts, coliforms, E. coli, Staphylococcus aureus, Salmonella spp., and Listeria monocytogenes. The microbiological detected levels were higher than the critical limits for prepreparing and cooking knives, chopping boards, working tables (both prepreparing and cooking), refrigerator (inside wall), bart, basket, and tray. E. coli, Salmonella spp., and Listeria monocytogens were not detected in any samples. However, Staphylococcus aureus were detected in rubber gloves for cooking and trench in the bottom at one foodservice establishment. In conclusion, these results suggest that a prerequisite programs guideline should be provided to improve the food safety levels at kindergarten foodservice establishments and the foodservice manager must maintain proper food safety technique for foodservice facilities, cooking utensils, and equipment at kindergarten foodservice establishments to prevent cross-contamination and spread of foodborne pathogens.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.350-357
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• 2014

BACKGROUND: Deicers such as calcium chloride ($CaCl_2$) and sodium chloride (NaCl) in Korea have been commonly used to reduce traffic accidents as well as injuries. However there have been adverse effects of deciders such as pollution of water and soil, and reduced productivity of agriculture as well as forest. This study aimed to investigate biological effects of the deicers against wheat, barley, and spinach. METHODS AND RESULTS: The germination of tested crop seeds exposed to chloride-deicers, $CaCl_2$ and NaCl was significantly reduced at over 3% concentration of chloride-deicers compared to the control. In spraying deicers to the seedlings of the crops, there was no symptom such as inhibition of growth rate or leaf elongation. However the germination of tested crop seeds was affected at 2% concentration of deicers when they were exposed continuously to deicers in soils. The growth of the shoot against $CaCl_2$ and NaCl treatments was very similar in wheat and barley whereas the shoot of spinach was the most susceptible. Based on these results, the sensitivity of the crops to the tested deicers was as follows: NaCl > $CaCl_2$ > mixture ($CaCl_2$ + NaCl). The length of shoots and roots of the seedlings grown in 1% treated soil was decreased. The biomass of all the seedlings decreased 1.5 to 4 times at 1%. CONCLUSION: These results indicate that the effects of salt deicers by inputting into soil against growing tested crops are more severe in germination and growth inhibition as well as biomass decrease.

• Analytical Science and Technology
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• v.10 no.4
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• pp.264-273
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• 1997

Anodic oxidation reaction was applied to remove trihalomethanes in an aqueous solution. Each component was determined by using solid phase microextraction(SPME) fiber and GC-ECD. Anodic and cathodic compartments were separated in order to protect contaminants and connected by $KNO_3$-agar bridge. The calibration graphs of the 6 THM components were shown good linearlity from a few ppb up to a few hundreds ppb concentration level. Anodes such as platinum(Pt), titanium(Ti). zircornium(Zr), titanium metal coated with iridium(Ti-Ir), and glassy carbon coated with mixed valence ruthenium(mv Ru) were tried to remove the THMs at different potentials. The best result was obtained on the Ti-Ir anode applied 9 volts DC. The electrode could effectively remove almost all the THM components from the stirring solution within about 1.5 hours. The glassy carbon electrode coated with mixed valence ruthenium showed excellent removing effect at the begining, but the maximum removing level was remained at 60% probably due to the destruction of the electrode surface. The concentration of chloroform, however, tends to be increased due to the electrode reaction producing the component at the condition.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.4
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• pp.279-285
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• 2015

This study studied samples taken off surfaces at three sites (Unit chairs, light handles, cuspidors) of 19 dental hospitals and 28 clinics located in Gyeonggi-do and Incheon, South Korea. The bacterial contamination levels of surfaces were $44.82{\times}10^3CFU/mL$ in cuspidors, higher than in unit chairs ($5.47{\times}10^3CFU/mL$) and light handles ($16.28{\times}10^3CFU/mL$). The values were statistically higher at dental hospitals than at dental clinics, the greater number of patients being associated with the higher bacterial cell count in the cuspidors. The results of identifying the strains isolated purely from surfaces at dental clinic showed Gram positive 47.3% and Gram negative 52.7%. Among Gram positive, the most numberous bacteria were Micrococcus luteus (10.9%), Bacillus pumilus (3.6%), and Staphylococcus aureus (3.6%). Among Gram negative, the most numberous bacteria were Acinetobacter ursingii (5.5%), Brevundimonas diminuta (4.5%), Chryseobacterium (Flavo.) indologenes (CDC IIb) (4.5%), and Methylobacterium sp. (4.5%). This study measures the level of bacterial contamination and identifies the strains isolated in dental clinics. It recognizes the importance of infection control, and the results of the study may be considered as the basis for establishing specific plans for prevention of infection.