• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.429-435
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• 2006

In this study multi-zone modeling program CONTAM 2.4 which is developed by NIST is used for modeling the air disinfection system which is consist of dilution, filtration, ultra violet germicidal irradiation (UVGI) for removing the indoor microorganism such as bacteria and fungus. Developed models those protect occupants against indoor microorganism generated in our daily life are enable to use for immune building simulation tool. Also, results indicate that those models are enable to compute the real situation that is almost impossible of carrying out experiment and identify the disinfection rate with highly reliance. Results also suggest that engineers will use these models as a design tool for the immune building system.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.652-656
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• 2009

A cylindrical ultraviolet (UV) sterilization system was developed for decreasing microorganisms in takju. The takju was passed through 110 strips of honeycomb-type teflon tubing with 9 UV lamps (1,395 W) set between the teflon tubes. Thus, during passage, the takju was effectively exposed to the UV rays without loss. In terms of the overall quality aspects of the takju, the optimum sterilization condition was set for 4 min at 2 L/min. A 2-3 log cycle decrease in viable cell numbers of total bacteria and fungi was observed at this operating condition. Quality changes in the UV-sterilized takju were examined via UV irradiation of samples followed by storage at 30oC for 8 days. To evaluate the quality changes, pH, amino nitrogen content, acidity, reducing sugar content, and viable cell numbers of total bacteria and fungi were measured. Increases in pH, acidity, and amino nitrogen content were observed in both the takju control and UV sterilized takju with increasing storage time. However, reducing sugar content was decreased in both samples. The L, a, and b values of the control takju and UV sterilized takju showed similar trends over the storage period. Viable cell numbers of fungi did not change in the control or UV sterilized takju during storage, showing approximately $10^8\;CFU/mL$ and $10^4-10^5\;CFU/mL$, respectively. In addition, viable cell numbers of total bacteria remained lower in the UV sterilized takju over 4 days compared to the non-sterilized takju.

• Restorative Dentistry and Endodontics
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• v.24 no.1
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• pp.222-232
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• 1999

The purpose of this study was to evaluate the effect of heated spreader on the sealing ability of lateral condensation, compared with regular cold spreader. Forty two extracted human teeth with single canal were randomly placed into 3 experimental groups, and four additional teeth were used as positive and negative controls. Each group was prepared with Ni-Ti Profile #40 using step-down technique and obturated with standardized colored gutta-percha cone by standard(cold) lateral condensation technique, warm lateral condensation technique with Endotec and hot spreader soaked in glass bead sterilizer, each with Sealapex sealer. Control groups were not obturated, but prepared. After 2 days in 2% methylene blue, the teeth were invested and made into transparent resin blocks. And then, each block was sectioned horizontally with microtome at 1, 2, 3, 4, 5 mm levels from the apex. The linear extent of dye penetration was examined with stereomicroscope at ${\times}$20 magnification. At each of 5 levels, ratio of the area of gutta-percha was obtained by calculating the area of gutta-percha to the total area of the canal. The data collected were then analyzed statistically using an analysis of variance(ANOVA) and Scheffe test. The results were as follows ; 1. All experimental groups produced the apical microleakage. 2. The mean leakage was 1.57${\pm}$0.76mm for cold spreader group, 0.86${\pm}$0.95mm for Endotec spreader group, and 0.64${\pm}$0.93mm for hot spreader group. The difference between hot spreader group and cold spreader group was statistically significant(p<0.05). 1. At the 1 mm level, the mean ratio of area of gutta-percha was 74.58${\pm}$13.15(%) for cold spreader group, 65.42${\pm}$14.62(%) for Endotec spreader group, and 80.72${\pm}$14.63(%) for hot spreader group. There was statistically significant difference between hot spreader group and Endotec spreader group(p<0.05). 2. At the 2mm level, the mean ratio of area of gutta-percha was 87.86${\pm}$11.22(%) for cold spreader group, 66.55${\pm}$14.02(%) for Endotec spreader group, and 92.93${\pm}$7.24(%) for hot spreader group. There was statistically significant difference between Endotec spreader group and other two spreader groups(p<0.05). 3. At the level 3, 4, 5 mm, there was no statistically significant difference between each group. Within the limits of the results of this experiment, warm lateral condensation technique with hot spreader soaked in a glass bead sterilizer demonstrated favorable apical sealing effect and improved density of gutta-percha mass. Thus, it is thought that this obturation technique is effective for clinical use and beneficial to reduce condensation forces, also economical and easy. Lateral condensation, Heated spreader, canal sealing, Microleakage.

• Journal of the Korean Society of Radiology
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• v.16 no.3
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• pp.195-201
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• 2022

This study aims to evaluate the feasibility of the disinfection of clinical ultrasound probes using the vapor fumigation method, which can quickly achieve high-level disinfection. Upon the inspection of the microbial contamination level of clinically used ultrasound probes, nine different types of bacteria were detected. The disinfection efficacy of 7.5% and 35% hydrogen peroxide (H₂O₂) was comparatively tested for the detected microbes. The 35% H₂O₂ demonstrated superior efficacy per disinfection duration. No significant change was observed in the rubber component of the ultrasound probes as a result of the 35% H₂O₂ disinfection treatment. The probes were contaminated with the microbes detected in the microbial contamination level inspection and subsequently disinfected using the novel medical disinfector that utilizes the vapor fumigation method. As a result, the disinfection using the novel device achieved 100% eradication of the microbes from the probes.This study demonstrates that the novel vapor fumigation method-based disinfector provides a faster and more powerful means of disinfection than the conventional disinfection methods. Therefore, the novel disinfector has the potential to be used as a convenient ultrasound probe disinfector in clinical settings.

• Journal of Food Hygiene and Safety
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• v.38 no.1
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• pp.26-30
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• 2023

In this study, we analyzed the microbial contamination level of ultraviolet sterilizer (UVS) chambers and suggested plans to improve hygiene management. In this study, UVS chambers targeted 98 UVS in some childcare centers in Jeollanam-do, Korea. Total aerobic bacteria and coliform bacteria were tested according to the Korean Food Code. Of the 98 UVS chambers, total aerobic bacteria were detected in 67 (68.4%) and coliform bacteria in 5 (5.1%). Six kinds of food-poisoning bacteria, including Salmonella spp., were not detected, but Bacillus cereus was detected in 1 (2.8%) out of 98 UVS chambers. According to the UV lamp replacement period, the detection rate of total aerobic bacteria was 3 (50%) out of 6 UVS within 3 months, 3 (60%) out of 5 UVS in 3 to 6 months, and 61 (70.1%) out of 87 UVS over 6 months. The detection rate of coliform bacteria according to the UV lamp replacement period was not detected within 6 months, however, they were detected in 5 (5.7%) out of 87 chambers after more than 6 months. The level of microbial contamination in the UVS chambers was higher as the lamp replacement period was longer. Considering these results, it was determined that the UVS chambers should be kept dry and clean, and the UV lamp should be replaced periodically. In addition, it is necessary to provide the staff catering for childcare centers with continuous education regarding the cleaning of UVS chambers and the replacement of UV lamps.

• Journal of Mushroom
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• v.15 no.4
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• pp.164-167
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• 2017

Biological efficiency (BE), the ratio of fresh mushrooms harvested per dry substrate weight, expressed as the percentage of Lentinula edodes, also known as shiitake, was determined using the 'Sanjo 701' strain stored in the Department of Mushroom at the Korea National College of Agriculture and Fisheries. The mycelia were grown in glass columns with varying levels of moisture content and varying mixing periods of 0.5, 1, 2, and 3 hours. The substrate was sterilized using a steam pressure autoclave sterilizer at normal and high pressure to avoid contamination. The results showed that mycelial growth (126 mm/15 days) was optimized at 55% moisture content. The best mycelial growth of 117 mm/15 days was obtained with 2 hours of mixing time. Normal pressure sterilization yielded better results with mycelial growth of 96 mm/15 days at $100^{\circ}C$ compared to 88 mm /15 days with sterilization at $121^{\circ}C$. Mycelial density was higher, i.e. 3(+++), with normal pressure sterilization compared to 2(++) with high pressure sterilization. Furthermore, sawdust mixed with 5% woodchips increased the substrate porosity and yielded higher mycelial growth. Thus, we demonstrated that the optimum harvest or potential increased yield of shiitake can be obtained by modulating moisture content, mixing time, and substrate porosity.

• The Korean Journal of Community Living Science
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• v.18 no.2
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• pp.247-263
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• 2007

This study was complied to analyze the professional agricultural techniques level and to suggest a desirable direction for the professional education system for women farmer. The research was conducted by using in-field surveys and interviews. Data was gathered by questionnaire from 147 women farmer in five specialized crop regions: strawberry, cucumber, rose, apple, and oyster mushroom. The results obtained are as follows. First, the technique levels in computer usage and electronic commerce, machinery usage, pesticide and fertilizer utilization, facility automation, and eco-agricultural cultivation were low. Second, the demand for professional education, evaluated through technique level by standard management diagnosis, was recognized. Areas of concern included: cucumber (temperature control, carbonic acid gas control, grading, funds management), strawberry (light control, soil temperature control, irrigation watering, shipping), rose (temperature control, light control, funds management, cooperated management), oyster mushroom (growth cabinet sterilizer), and apple (flower bud pinching, defloration, fruit thinning, funds management). Based on the results of this study, the following are suggestions for the planning of a professional education system for women farmer. First, it needs to address formal education in marketing, machinery usage, facilities automation, and techniques in pesticide and fertilizer utilization. Second, it needs to be a multi- level program with appropriate terminology at every level which is suitable to each age and ability of women farmer. Third, it needs a more comprehensive manual developed by need analysis of women farmer and a larger lecturer pool for professional education.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.6
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• pp.264-269
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• 2019

The design for household sterilizer applying UV LED was studied. Based on UV LED sterilization distance and time data, the concept of home disinfectioner design was presented. Using technologies such as computer aided design software, 3D printing and laser cutting, etc., three different UV LED operating method models were produced. The final design was derived by conducting an analysis of the product's merits and demerits on the three plans from the result of each model.

• The Korean Journal of Food And Nutrition
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• v.4 no.1
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• pp.81-90
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• 1991

This study was conducted a comprehensive survey of 39 elementary schools operating school lunch program in Seoul area. The purpose of this study was to investigate the realities of school lunch program. This method of the research was based on the interview survey with dietitian working at each school with prepared questionnaire. The survey was conducted for 16 days from Dec. 5 to Dec. 20., 1990. The results of this study were as follows ; (1) The average numbers of children supplied with food were 1,244 for each school. It was about 44.3Bb of the students enrolled in the school. The average feeding cost was 738 won per a child for a day. (2) Only one school was operating nutritional education as a regular educational program, and others were operating nutritional education off and on. (3) All nutrient intake except energy were higher than the RDA for school lunch program. (4) The ratio of animal food was 46.2%, and that of vegetable food was 53.8%. (5) The ratio of schools without sterilizer cabinet came to 56.4%, and that of schools without warmer was 97.4%. (6) The facilities for drainage, lighting, ventilation, anti-rat of a cookery were comparatively good.

• Journal of the Korea Safety Management & Science
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• v.12 no.3
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• pp.37-52
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• 2010

This study is aimed at proposing the national policy for medical device control system in Korea as deeply analysed the present status of the system. On 1979, Korean government had started to inspect 24 kinds of the medical devices such as X-ray diagnostic equipments, medical sterilizer and etc. mostly imported from advanced countries which USA, Germany and Japan for the first time according to the Pharmaceutical Affairs Law. However medical devices were becoming consideration as an important partner of diagnosis, curing and alleviation of diseases by medical doctors and also much important keeping the health at home. Furthermore medical devices industry can be designated as a national growth engine industry. So it is necessary not only to harmonize to international standards but also the harmonization of the system including pre-market application and post-market surveillance, is strongly needed by the Korea Food and Drugs Administration(KFDA).