• Biomolecules & Therapeutics
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• v.23 no.6
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• pp.582-589
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• 2015

Several theories emphasize that aging is closely related to oxidative stress and disease. The formation of excess ROS can lead to DNA damage and the acceleration of aging. Vigna angularis is one of the important medicinal plants in Korea. We isolated vitexin from V. angularis and elucidated the lifespan-extending effect of vitexin using the Caenorhabditis elegans model system. Vitexin showed potent lifespan extensive activity and it elevated the survival rates of nematodes against the stressful environments including heat and oxidative conditions. In addition, our results showed that vitexin was able to elevate antioxidant enzyme activities of worms and reduce intracellular ROS accumulation in a dose-dependent manner. These studies demonstrated that the increased stress tolerance of vitexin-mediated nematode could be attributed to increased expressions of stress resistance proteins such as superoxide dismutase (SOD-3) and heat shock protein (HSP-16.2). In this work, we also studied whether vitexin-mediated longevity activity was associated with aging-related factors such as progeny, food intake, growth and movement. The data revealed that these factors were not affected by vitexin treatment except movement. Vitexin treatment improved the body movement of aged nematode, suggesting vitexin affects healthspan as well as lifespan of nematode. These results suggest that vitexin might be a probable candidate which could extend the human lifespan.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.8
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• pp.1121-1127
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• 2014

Many studies have been done to measure and analyze color for various purposes. Visual assessment has lack of objectivity and the equipment for color measurement is very expensive. In this study, we developed a device for quantitative analysis of the color using optical elements. With the color sensor, the ratio of RGB was calculated by measuring the light intensity that is reflected from an object. Inverse transformation of optical signal was performed to detect the color density. The suggested color analyzer can detect color information as well as sample concentration. Results of this study are expected to be used in various medical fields such as pH indicator and urine analysis.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.386-392
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• 2015

A novel recombinant bacmid, bEasyBm, that enables the easy and fast generation of pure recombinant baculovirus without any purification step was constructed. In bEasyBm, attR recombination sites were introduced to facilitate the generation of a recombinant viral genome by in vitro transposition. Moreover, the extracellular RNase gene from Bacillus amyloliquefaciens, barnase, was expressed under the control of the Cotesia plutellae bracovirus early promoter to negatively select against the nonrecombinant background. The bEasyBm bacmid could only replicate in host insect cells when the barnase gene was replaced with the gene of interest by in vitro transposition. When bEasyBm was transposed with pDualBac-EGFP, the resulting recombinant virus, EasyBm-EGFP, showed high levels of EGFP expression efficiency compared with that of non-purified recombinant virus BmGOZA-EGFP, which was constructed using the bBmGOZA system. In addition, nonrecombinant backgrounds were not detected in unpurified EasyBm-EGFP stocks. Based on these results, a high-throughput system for the generation of multiple recombinant viruses at a time was established.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.1
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• pp.159-164
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• 2015

Color is distinguished due to the light in which natural light is reflected by object and made with combination of RGB(red, green, blue; three colors). This study proposes color analysis system with optical method to be used conveniently. Color information of sample is determined with the optical sensor. By using the CIE diagram in particular, it detects purity value and wavelength. The method to distinguish color is very economical, simple, and convenient. The result can be used to confirm accurate information of color for various applications.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.8
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• pp.94-103
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• 2020

This study investigated the effects of ultrasonic nanocrystal surface modification (UNSM) on the deteriorated surface of AISI SUS316L additively manufactured (AM) using the powder bed fusion (PBF) technique. Specifically, the effects of UNSM conditions on surface topology, hardness, and anti-corrosion were examined. Before UNSM treatment, the stainless steel 316L powder was processed via the PBF machine to prepare a substrate. We observed surface changes due to UNSM treatments in PBF SUS316L substrates and examined the correlation between topology changes, roughness, hardness, and anti-corrosion. After UNSM treatment, the coarse as-built surface was refined, and a regular micro-profile was implemented. Compared to the non-treated PBF sample, the waviness and roughness of the surfaces after UNSM treatment decreased by up to 56.0% and 94.5%, respectively, and decreased further as the interval decreased. The hardness improved by up to 63.0% at a maximum depth of 500 ㎛ from top surface by the UNSM treatment. The results of the corrosion test showed that the corrosion resistance of the UNSM specimens was moderately improved compared to that of the untreated surface. This study confirmed that UNSM is an effective post-processing technique for additively manufactured parts.

• Journal of Marine Bioscience and Biotechnology
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• v.9 no.1
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• pp.8-13
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• 2017

Cost-effective microalgae harvesting methods are necessary for economical production of algal biodiesel. In this study, membranes with various pore sizes and materials were examined for their potentials in application to gravity-filtration of Tetraselmis sp. KCTC12432BP. For this test, 10 L of Tetraselmis sp. culture (2 g/L) was loaded on each membrane and filtration rates were measured. Among the tested materials, a woven cotton fabric showed the fastest water drain rate (0.73 L/hr) without serious cell leakage. Cell density of the concentrates after filtration was 6.8 g/L, indicating 3.4-fold concentration compared with the initial algal culture. The result suggests that the woven cotton fabric could serve as filtration membrane for harvesting Tetraselmis sp. among the tested ones.

• Korean Journal of Agricultural Science
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• v.44 no.2
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• pp.221-227
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• 2017

This study is the evaluation of the 'Tunak forest recreation and ecotourism development project' which will be completed in 2018 with sole source of funding from Korea. A survey was conducted to evaluate the status of the project being carried out in Lombok island, Indonesia, through the evaluation principles and criteria of the OECD Development Assistance Committee (DAC). Survey participants were stakeholders of the Official Development Assistance (ODA) project and local residents. Overall, the respondents had a good impression of this ODA project and expected they would contribute to the development of their community and region. However, respondents were not well aware of the ODA project being carried out in the Tunak region and thus more efforts should be made to help the local residents understand the positive outcome of the project and to promote the ongoing cooperation between Korea and Indonesia in the forestry sector. Results of this study showed that the projects have been effectively carried out and the impact of the project was well perceived by the recipient country. In addition, this positive perception of Korea is expected to help recreation and ecotourism business progress in the region. Therefore, we believe that the project should continue to be carried-out in the future and we expect that related companies will be able to operate on its own eventually. As it is difficult to evaluate the outcome of an ongoing project precisely, this study should be conducted again after the project completion and the results can be compared to the present results so that the effectiveness of ODA project can be more accurately determined.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.22-28
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• 2016

The monitoring and measurement of the motion of a human joint is very important in screening for degenerative brain diseases and tracking the rehabilitation process. Since there are various medical fields to benefit from angular motion measurement, the necessity for monitoring of human joint movement is increasing. In this study, the optical sensor is composed of a light emission unit with a red LED and an optical fiber, and a reception unit with an arrangement of three photodiodes. The angular detection range was widened with the use of multiple photodiodes and the developed algorithm. The result will be useful for designing an effective angular sensor with low cost and small size.

• Journal of Korean society of Dental Hygiene
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• v.17 no.1
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• pp.111-122
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• 2017

Objectives: Coriolus versicolor is an edible mushroom with physiological activities that has been used in traditional medicine. The aim of this study was to investigate the antimicrobial activity of extracts obtained from Coriolus versicolor against oral pathogens. Methods: The antimicrobial activities of various extracts of Coriolus versicolor were examined by disc diffusion assay, and minimum inhibitory concentration (MIC) of these extracts were also was determined by broth dilution method. The growth inhibition effect of extracts was measured at 600 nm for 12 hrs against Streptococcus ratti, Streptococcus criceti, Aggregati--bacter actinomycetemcomitans, Actinomyces viscosus, and Actinomyces israelii. Results: Coriolus versicolor extracts showed antimicrobial activities against all nine oral pathogens through disc diffusion assay. The ethanol extract and ethyl acetate extract differed significantly compared with acetone extract against Streptococcus ratti, Streptococcus criceti, Actinomyces viscosus, Actinomyces israelii and Aggregatibacter actinomycetemcomitans (p<0.05). These extracts exhibited MIC ranges of 2.63 to >10.50 mg/ml against the tested bacteria. The ethanol extract from Coriolus versicolor showed lower MIC values of 2.63 to 5.25 mg/ml. According to the obtained growth curve, the extracts of Coriolus versicolor were more effective against Actinomyces viscosus. Conclusions: The acetone, ethanol, and ethyl acetate extracts from Coriolus versicolor showed antimicrobial activities against Streptococcus mutans, Staphylococcus aureus, Streptococcus sanguinis, Streptococcus sobrinus, Streptococcus ratti, Streptococcus criceti, Aggregatibacter actinomycetemcomitans, Actinomyces viscosus, and Actinomyces israeli.i Therefore, they could be considered as natural oral antimicrobial agents against oral pathogens.

• Korean Journal of Pharmacognosy
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• v.47 no.2
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• pp.179-185
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• 2016

Ginger (Zingiber officnale Roscoe, Zingiberaceae), which is a well-known food seasoning, has been used as a traditional medicine for the treatment of gastrointestinal disorder, vomiting and cough in Korea, China and Japan. Ethanol extract from the dried ginger (DG) was successively partitioned as methylene chloride, ethyl acetate, n-butanol and $H_2O$ soluble fractions. Among those fractions the ethyl acetate soluble fraction (EDG) showed the most potent DPPH radical scavenging and superoxide quenching activities. To know the effect of antioxidant activities of EDG, we tested the activities of superoxide dismutase (SOD) and catalase together with oxidative stress tolerance and intracellular ROS level in Caenorhabditis elegans. To investigate whether EDG-mediated increased stress tolerance was due to regulation of stress-response gene, we quantified SOD-3 expression using transgenic strain including CF1553. Consequently, EDG elevated SOD and catalase activities of C. elegans, reduced intracellular ROS accumulation in a dose-dependent manner. Moreover, EDG-treated CF1553 worms exhibited significantly higher SOD-3::GFP intensity.