• Journal of Radiation Protection and Research
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• v.22 no.2
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• pp.85-95
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• 1997

TLD and film badges have been traditionally used as formal dosimeters in personal monitoring and are still most widely used. Recently, electronic personal dosimeters based upon Si diode or miniature G-M tube were developed and are getting attractions due to their merits of active nature ; indication of dose rates and the commutative dose, and facilitation of record keeping and radiological control. Response characteristics of the electronic dosimeters including reproducibility, accuracy, linearity, energy and angular dependencies, detection threshold, and response time were examined for three commercial types ; EPD2, STEPHEN6000, and PD-3i. The results were compared with the relevant requirements of IEC standards and Ontario Hydro standards to conclude that their general performances were good. Some specific deficiencies, e.g. incapability of shallow dose measurement of STEPHEN6000, and PD-3i, however, should be corrected to be used as a formal dosimeter.

• Journal of Dental Rehabilitation and Applied Science
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• v.35 no.3
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• pp.160-169
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• 2019

Purpose: The purpose of this study was to evaluate the antimicrobial effects of a toothbrush with light-emitting diodes (LEDs) on periodontitis-associated dental biofilm attached to a zirconia surface by static and dynamic methods. Materials and Methods: Zirconia disks (12 mm diameter, 2.5 mm thickness) were inserted into a 24-well plate (static method) or inside a Center for Disease Control and Prevention (CDC) biofilm reactor (dynamic method) to form dental biofilms using Streptococcus gordonii and Fusobacterium nucleatum. The disks with biofilm were subdivided into five treatment groups-control, commercial photodynamic therapy (PDT), toothbrush alone (B), brush with LED (BL), and brush with LED+erythrosine (BLE). After treatment, the disks were agitated to detach the bacteria, and the resulting solutions were spread directly on selective agar. The number of viable bacteria and percentage of bacterial reduction were determined from colony counts. Scanning electron microscopy (SEM) was performed to visualize alterations in bacterial morphology. Results: No significant difference in biofilm formation was observed between dynamic and static methods. A significant difference was observed in the number of viable bacteria between the control and all experimental groups (P < 0.05). The percentage of bacterial reduction in the BLE group was significantly higher than in the other treated groups (P < 0.05). SEM revealed damaged bacterial cell walls in the PDT, BL, and BLE groups, but intact cell walls in the control and B groups. Conclusion: The findings suggest that an LED toothbrush with erythrosine is more effective than other treatments in reducing the viability of periodontitis-associated bacteria attached to zirconia in vitro.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.285-290
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• 2003

This study was conducted to select the bacteriocin-producing microoreanism cultivated in the rice bran culture and to characterize the produced bacteriocin for the further purpose of economical and anti-bacterial rice bran protein film. Pseudomonas putida 21025 was cultivated from rice bran and identified as a producer of a bacteriocin which showed bactericidal activity against Pseudomonas aeruginosa 9027. Bacteriocin produced by Pseudomonas putida 21025 showed a broad spectrum of activity against spoilage and soil bacteria. The activity of the bacteriocin produced by Pseudomonas putida 21025 decreased after 1 hr of staying at the temperature of $50^{\circ}C$, and with the presence of some organic solvents, except hexane and ethanol. However, the bacteriocin activity was stable throughout the pH ranges of 6-9 for 2 hrs, at the temperature lower than $50^{\circ}C$, and with the presence of ethanol for 3 hrs. The bacteriocin was partially purified by 50% ammonium sulfate precipitation followed by subsequent dialysis. Direct detection of the partially purified bacteriocin on SDS-PAGE suggested that it had an apparent molecular mass of about 21.6 kDa.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.4
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• pp.10-16
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• 2008

This study investigated electromagnetic interference(EMI) shielding effectiveness(SE) of the aluminum film, conductive fabric and nano carbon black carbon fiber reinforced composites. We fabricated carbon fiber reinforced composites filled with nano carbon black where they bonded aluminum film and conductive fabric. The measurements of SE were carried out frequency range from 300MHz to 1.5GHz. It is observed that the SE of the bonded aluminum film and conductive fabric composites is the frequency dependent, increase with the increase in filler nano carbon black content. The aluminum film bonded composites showed higher SE compared to that of carbon black and conductive fabric. The aluminum film bonded epoxy composite was shown to exhibit up to 80dB of SE. The result that aluminum film bonded composite can be used for the purpose of EMI shielding as well as for some microwave applications.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.3
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• pp.133-141
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• 2007

There are produced more than 600,000 tons of seaweeds every year along the coast of the Korea. Jeonnam province, south-west coast area, of Korea is producing 93% of total amounts of seaweeds. The laver, sea mustard, and tangleweed maintain stability in the output and has been exported as a simple product processing through drying or salting. It was evaluated the low value-added products and limited the expansion for the consumption of seaweeds. The seaweeds contains 40-60% carbohydrate and structurally different compared with land plant. The dietary fiber from seaweeds has been known the function of facilitating the bowl movement, excretion the heavy metal in the body, lowering the blood cholesterol level, anti-coagulant of blood, and anticancer. Especially, brown algae including sea mustard, seaweed fusiforme, and tangleweed contains alginic acid, laminarin, mannitol, fucoidan which are lowering the blood cholesterol level, lowering blood pressure, and fusion of blood clot. Agar-agar, carrageenan, and porphyran compound in red algae are known to antimutagenicity and anticoagulant function. In spite of potential of seaweed as a main bio-resource, there are lack of research to facilitate the consumption with its functional properties and consumers are unsatisfied with simple processing products. Also, the seaweed by-product dump into the sea and cause pollution of the seawater. Therefore, there are needed the scheme to promote the consumption of seaweeds. The development of value-added products, finding functional properties from seaweeds, development the functional feed for animal using seaweed by-products, and utilization of unused algae for food or other industrial uses will increase fisherman's income as well as serve as an aid for the people health due to its functional properties. Using by-product of seaweed and unexploited seaweed are needed to development of bio-degradable food packaging material and functional feed for animal.

• Journal of Radiation Protection and Research
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• v.21 no.3
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• pp.147-153
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• 1996

The Korea Atomic Energy Research Institute(KAERI) conducted a intercomparison study for personnel dosimetry services in Korea to enhance the accuracy and precision of the dosimetry system. Nine types of dosimeters(6 TLD, 3 film badge) from 7 institutions took part in this intercomparison study. Each participant submitted 30 dosimeters including transit control for irradiations. Both TLDs and film badges were irradiated with Cs-137 gamma, Sr/Y-90 beta and 4 X-ray beams in ISO wide series. Four dosimeters were irradiated on phantom with same dose equivalent for each field category. The delivered dose equivalent was in the range of $0.1{\sim}10mSv$. The participants assessed the results of their dosimeter readings in terms of the ICRU operational quantities for personal monitoring, Hp(10) and Hp(0.07). Most participants except 1 dosimeter estimated the delivered dose equivalent with biases less than ${\pm}25%$ for Cs-137 and Sr/Y-90. But for X-rays, the biases exceeded ${\pm}35%$ in some cases bacause the dose evaluation algorithm was based on the ANSI N13.11 X-ray fields which are different from those given by ISO.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.4
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• pp.281-286
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• 2005

To develop transgenic birdsfoot trefoil (Lotus corniculatus L.) plants tolerant to environmental stress, Arabidopsis NDPK gene (AtNDPK) was introduced into birdsfoot trefoil plants using Agrobacterium-mediated transformation and expressed powerfully under the control of the SWPA2 promoter. The expression vector, pCAMBIA2300 was used for introduction of AtNDPK gene into birdsfoot trefoil plants. The transformed calli were selected on kanamycin containing medium and then regenerated. The transformed birdsfoot trefoil plants were cultivated fur 4 months on BOi2Y medium. Genomic DNA PCR and Southern blot analysis confirmed the incorporation of AtNDPK into the birdsfoot trefoil genome.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.2
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• pp.83-90
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• 2006

To develop transgenic birdsfoot trefoil (Lotus corniculatus L.) plants tolerant to environmental stress, Arabidopsis NDPK gene (AtNDPK) was introduced into birdsfoot trefoil plants using Agrobacterium-mediated transformation and expressed powerfully under the control of the E35S promoter. The expression vector, pEN-K was used for introduction of AtNDPK gene into birdsfoot trefoil plaits. The transformed calli were selected on kanamycin containing medium and then regenerated. The transformed birdsfoot trefoil plants were cultivated for 4 months on BOi2Y medium. Genomic DNA PCR and Southern blot analysis confirmed the incorporation of AtNDPK into the birdsfoot trefoil genome.

• Journal of Korean Society on Water Environment
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• v.36 no.2
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• pp.148-152
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• 2020

The quantitative accuracy of dry rehydratable film method was compared with the standard culture method to analyze the applicability of dry rehydratable film in the total aerobic bacteria test for water. The materials used in this study were 500 cases of water and were tested according to the Korean official test method for drinking water. The mean value of the total aerobic bacteria in plate count agar(PCA) and MC-Media Pad AC(MAC) were 2.6 ± 1.1 Log cfu/mL and 2.6 ± 1.2 Log cfu/mL. The p value and correlation coefficient(R²) were 0.933 and 0.9985 between the PCA and MAC, respectively, indicating no significant difference and very high correlation. According to the water types, the p value and R² were 0.887 and 0.9911 in the PCA and MAC. In the purified water, the p value was 0.973 and R² was 0.9934 in the PCA and MAC of other water. In each type of water, there were no significant differences between the PCA and MAC, and the correlation was very high. Thus, it is suggested that the MAC would be available for total aerobic bacteria test for water.

• Journal of the Korea Convergence Society
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• v.10 no.10
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• pp.27-31
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• 2019

The purpose of this study is to gather biofilm of unit chair waterline in the laboratory, to analyze microorganisms, to apply the existing draw-off method and the method of using disinfectant, and to compare the change of the number of microorganisms. The water was provided by the waterline of the unitchair, and the gathered samples were cultured with the use of R2A agar plate. Bacterial species separated through the identification of microorganisms were analyzed. To identify the decrease of microorganism for draw-off, samples were gathered in the intervals of 30 seconds, 60 seconds and 120 seconds, and to identify the effect of disinfectant, samples after disinfection were gathered. The quantitative comparison of microorganisms through the gathered samples was done by SPSS program. The number of identified bacteria are 8 species, most of which are gram-negative bacterium, and Sphingomonas type. The rapid decrease of the number of microorganism through draw-off for 60 seconds was confirmed, and microorganisms after disinfection weren't detected right away. Based on the method and result of this study, the water pipe of unit chair, which can be neglected easily, can be managed, so cross infection can be prevented, and systemic management can be possible.