• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.169-179
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• 2000

The purpose of this study is to develop the system which convert the optical difference of teeth texture between intact enamel and incipient caries lesion into shade difference by laser fluorescence and to develop new and simple caries activity test using laser fluorescence. The experimental design of this study consists of three parts. In first part, a new method for the in vitro assessment of changes in initial enamel caries lesion of Bovine teeth using laser fluorescence is tested. In second part, in vivo assessment undertaken. Number of teeth which showed incipient carious lesion on buccal surface examined by laser fluorescence was compared with the caries activity test of $Cariescreen^{(R)}$ test and other oral environmental test of dDfFtT. In third part, new caries activity test measured by laser fluorescence was developed on the basis of above results and evaluated the sensitivity, specificity, and diagnostic power. Optical density measured by laser fluorescence was increased as increasing the depth of incipient carious lesion and showed high correlation$(\gamma=0.7015)$ with lesion depth. Optical density showed direct proportion to lesion depth. Linear equation was obtained between the optical density and the lesion depth by regression analysis. The result of caries activity test with laser fluorescence showed high correlation with those of $Cariescreen^{(R)}$ test and dDfFtT examination. Caries activity test with laser fluorescence showed 48% of sensitivity, 52% of specificity, and 45% of diagnostic power on the basis of dDfFtT examination, and also showed 48% of sensitivity, 51% of specificity, and 36% of diagnostic power on the basis of $Cariescreen^{(R)}$ test. In regard above result, caries activity test with laser fluorescence considered to be reliable for caries activity test compared with other oral environmental test. and it was also considered to be practical because it would be simple, inexpensive, and time saving method.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.4
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• pp.363-373
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• 2018

In recent years, parabens used as preservatives in cosmetics have become a problem of human safety. Therefore, in this study, we tried to evaluate the preservative efficacy of 1,3-butylene glycol, 1,2-hexanediol, and 1,2-pentanediol as a preservative system to replace parabens. 1,3-Butylene glycol was added to cosmetic creams at a concentration of between 5 and 25%. The preservative efficacy of 1,3-butylene glycol was determined using a M-3 challenge test, as recommended by the Personal Care Products Council (formally CTFA). The alkane diols, such as 1,2-hexanediol and 1,2-pentanediol, were assessed in a similar manner. An evaluation of the preservative efficacy of 1,3-butylene glycol revealed that it was effective against all tested microbial strains at a concentration of 25%. We also investigated the efficacy of combinations of 0.3% phenoxyethanol and 0.1% ethylhexylglycerin. Finally, we tested the alkane diols, including 1,2-hexanediol and 1,2-pentanediol, as an alternative to the preservative 0.3% phenoxyethanol. Both 1% 1,2-hexanediol and 1% 1,2-pentanediol demonstrated preservative efficacy. Taken together, our study demonstrated that the formulation of 25% 1,3-butylene glycol and 0.1% ethylhexylglycerin, 1% 1,2-hexanediol, and 1% 1,2-pentanediol had the best preservative efficacy of the compositions tested. Thus, this study suggests that the formulation is a possibility of substituting parabens preservatives, which has been used in cosmetics and has become a safety issue.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.772-781
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• 2018

In this study, we investigated antioxidant, antimicrobial and cytoprotective effects of 50% ethanol extract and ethyl acetate fraction from rhizomes of Belamcanda chinensis (L.) DC. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activities ($FSC_{50}$) of the 50% ethanol extract and ethyl acetate fraction were 621.5 and $253.0{\mu}g/mL$, respectively. Total antioxidant capacities ($OSC_{50}$) of the extract and fraction were 13.6 and $3.0{\mu}g/mL$, respectively. Minimum inhibitory concentrations (MIC) of the ethyl acetate fraction for Staphylococcus aureus and Candida albicans were 156, $1,250{\mu}g/mL$, respectively, indicating similar or higher levels of those of using methyl paraben. Cytoprotective effects of the 50% ethanol extract against $^1O_2$-induced cellular damage (${\tau}_{50}$) showed in a dose dependent manner at 4 to $64{\mu}g/mL$. ${\tau}_{50}$ of the 50% ethanol extract, ethyl acetate fraction and (+)-${\alpha}$-tocopherol at $16{\mu}g/mL$ were 36.4, 45.0 and 45.8 min respectively, and the ethyl acetate fraction showed cytoprotective effects similar to (+)-${\alpha}$-tocopherol. In ultraviolet B radiation-induced HaCaT cell damage, the ethyl acetate fraction decreased intracellular reactive oxygen species (ROS) up to 45.9% at $8{\mu}g/mL$. Also in $H_2O_2$-induced HaCaT cell damage, the ethyl acetate fraction significantly increased the cell viability at $0.5{\sim}8.0{\mu}g/mL$. As a result of chemical analyses of the ethyl acetate fraction, the presence of flavonoids and polyphenol such as irisflorentin, irigenin, tectorigenin, resveratrol, iridin and tectoridin were identified. In conclusion, the extract/fraction from rhizomes of B. chinensis can be applied as a natural antioxidant and antimicrobial material to cosmetics.

• Microbiology and Biotechnology Letters
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• v.46 no.4
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• pp.360-371
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• 2018

Extracts and fractions of Anemarrhena asphodeloides Bunge were prepared and their physiological activities and components were analyzed. Antimicrobial activities of the ethyl acetate and aglycone fractions were $78{\mu}g/ml$ and $31{\mu}g/ml$, respectively, for Staphylococcus aureus and $156{\mu}g/ml$ and $125{\mu}g/ml$, respectively, for Pseudomonas aeruginosa. 1,1-Diphenyl-2-picrylhydrazyl free radical scavenging activities ($FSC_{50}$) of 50% ethanol extract, ethyl acetate fraction, and aglycone fraction of A. asphodeloides extracts were $146.2{\mu}g/ml$, $23.19{\mu}g/ml$, and $71.06{\mu}g/ml$, respectively. The total antioxidant capacity ($OSC_{50}$) in an $Fe^{3+}$-EDTA/hydrogen peroxide ($H_2O_2$) system were $17.5{\mu}g/ml$, $1.5{\mu}g/ml$, and $1.4{\mu}g/ml$, respectively. The cytoprotective effect (${\tau}_{50}$) in $^1O_2$-induced erythrocyte hemolysis was 181 min with $4{\mu}g/ml$ of the aglycone fraction. The ${\tau}_{50}$ of the aglycone fraction was approximately 4-times higher than that of (+)-${\alpha}$-tocopherol (${\tau}_{50}$, 41 min). Analysis of $H_2O_2$-induced damage of HaCaT cells revealed that the maximum cell viabilities for the 50% ethanol extract, ethyl acetate fraction, and aglycone fraction were 86.23%, 86.59%, and 89.70%, respectively. The aglycone fraction increased cell viability up to 11.53% at $1{\mu}g/ml$ compared to the positive control treated with $H_2O_2$. Analysis of ultraviolet B radiation-induced HaCaT cell damage revealed up to 41.77% decreased intracellular reactive oxygen species in the $2{\mu}g/ml$ aglycone fraction compared with the positive control treated with ultraviolet B radiation. The findings suggest that the extracts and fractions of A. asphodeloides Bunge have potential applications in the field of cosmetics as natural preservatives and antioxidants.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.452-461
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• 2020

The purpose of this study is to identify how learners perceive mobile technology-based learning materials. For this purpose, two methods were utilized. Using multi-dimensional scale(MDS), it was identified that how learners perceive each type of learning materials using mobile technology. Through semantic differential scale(SDS), learners' perception of the difference between mobile learning materials and existing traditional learning materials was analyzed. As a result, learning materials using mobile technology were classified into as follows : the dimension of interaction with the content; the sense of presence. Learners perceived that mobile learning materials had characteristics of 'active', 'learner-centric', 'multi-sensory', and 'stimulating interest'. The significance of this study was to empirically and comprehensively investigate learners' perception for the characteristics of various mobile learning materials.

• Journal of the Korea Convergence Society
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• v.8 no.2
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• pp.163-168
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• 2017

The feasibility evaluation of public projects has been carried out mainly in the economic analysis. However, items of political, technological and balanced regional development aspects are further evaluated by applying analytic hierarchy process, This paper suggests to analyzes preliminary feasibility study of construction and research & development project during the past three years and to verify correlation between B/C ratio and AHP weight. The result shows that the correlation between cost benefit ratio and the weight of the hierarchy is 0.744 in construction projects and 0.899 in research & development project. Namely, AHP weight be under the control of B/C ratio and is devoted to its role against expectation. Therefore it must be sufficiently discussed in various designs of studies to maximize the effects of AHP analysis.

• Journal of the Korea Convergence Society
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• v.7 no.1
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• pp.167-176
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• 2016

The Border Area Support Act(2000) has policy goal convergence to improve living conditions, to conserve natural environment, and to prepare national unification in this area. The purpose of this study is to evaluate whether the support until now meet the policy goal or set a question on policy itself. Variation of statistical indicators related with policy goal for the period 2000-2014 has analyzed and compared with local government's evaluation report. It is found out that resident's living condition has improved in spite of several political fallacies, but the support policy can damage natural environment and cause conflict with military regulations constantly. Under current inter-Korean relation, it is desirable to minimize conflicts between political bodies in Border Area.

• Journal of the Korean Institute of Telematics and Electronics
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• v.8 no.3
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• pp.1-14
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• 1971

A relay servo, one of the nonlinear sytsems, is inherently compact compared to a linear system for an equivalent control problem. The power element or actuator is not adjusted proportionally in accordance with an error signals but rather is switched abruptly between several discrete conditions. Usually switched conditions are off, full, forward or full reverse. The relay system is a particularly simple and compact one, but probably more effort has been expended on its analysis and design than on all other systems together. Early studies in the art were made by Goldfarb, austin, Oppelt and Kochenburger on the describing function method, which can be used as an approximate check on the stability of the system. The describing function method is based on the assumption that any periodic wave could be approximated as a fundamental one in wide ranges of practical applications. A relay servo system usually operates on a limit cycle condition as the loop gain increases. The stability analysis compensation or any improvement effort based on the describing function method sometimes may present considerable discrepancies on physically realized practical systems. An approach to exact periodic solutions of a relay servo system is much important for the analysis, design and system improvement. This paper dells with periodic solutions of a relay servo system on the basis of describing function and generalized chopper wave form which is composed of infinite number of harmonic series. Various ways of graphical representation were attempted to get periodic solutions, some of which have shown its validity in rapid approach to exact solutions and also in judgement of system behavior.

• 한국유가공학회:학술대회논문집
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• 1996.11a
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• pp.18-29
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• 1996

1. CWPC중의 새로운 생리활성물질의 검색 Mouse 임파세포의 증식효과를 지표로 하는 면역기능을 검토하여 CWPC중의 면역 부활작용을 갖는 새로운 성분의 검색을 실시하였다. CWPC를 여러 가지 분획법으로 분획하여 mouse 임파세포의 증식효과를 지표로 면역 활성성분을 검색하였다. 그 결과 gel filtration, 음이온교환법을 사용하여 분획한 당을 다량 포함한 부분에 강한 면역부활담당세포에 대하여 증식활성을 나타내는 물질을 발견하였다. 이 물질은 SDS-PAGE상에서 분자량이 약 16kDa에 위치하여 Ca, P 및 당쇄를 포함한 물질이며, 이것을 GPP로 하였다. GPP에는 우유케이신의 trypsin분해물이며 Ca와 무기인을 풍부하게 포함하는 ${\beta}$-CPP와 유사한 phosphoserin 영역을 갖는 성분과 갖지 않는 성분의 2종류가 존재하며, 각각의 면역 부활활성이 인정되었다. 각 성분의 아미노산 분석, 당 분석의 결과에서 지금까지 보고된 우유중의 면역 담당세포에 대한 증식활성을 갖는 물질과는 상이한 성분인 것으로 밝혀졌다. 더욱이 이 활성물질 (GPP)은 PP cell에서도 동등한 활성이 있는 것으로 판단되었다. 이러한 결과를 종합하여 보면 CWPC중에서 지금까지 알려지지 않았던 새로운 면역 부활물질이 존재하며, 그 성분에는 CPP와 유사한 phophoserine 영역이 존재하는 성분이 포함되어 있고, N-글리코실 결합의 당쇄가 존재하는 것으로 시사되었다. 이 성분은 전신면역의 지표인 비장세포에 대해서만이 아니고, 장관면역계에 중요한 역할을 담당하는 PP cell에서도 활성이 있는 것으로 보아 전신 및 국부적인 면역기능의 부활성분으로서 응용의 가능성이 시사되었다. 2. GPP의 면역담당세포에 대한 증식활성의 메카니즘의 검토 CWPC중의 GPP의 면역담당세포증식활성의 메카니즘을 해명하기 위해 먼저 이 성분중의 어느 부분이 활성에 관여하는지를 pronase 분해 및 phophoserine 영역을 인식하는 항체를 사용하여 검토하였다. 그 결과 pronase 분해처리에서도 활성의 감소를 나타내지 않았으므로 이러한 활성에는 당이 필수 불가결하다는 점이 시사되었다. 또한 phosphoserine 영역을 인식하는 항체에 의해서도 활성은 감소하지 않는 것으로 보아 phosphoserine 영역이 세포증식활성에 관여하지 않는 것으로 판단되었다. 또한 분획한 면역담당세포에 대한 증식활성을 측정하는 것으로 이 성분의 표적면역담당세포를 동정하여, B세포에 대해서만 특이적으로 증식활성을 나타내는 것으로 밝혀졌다.

• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.325-329
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• 2018

In this study, polyphenols were extracted from Angelica, which are known to have a high antioxidant content and the extraction process was optimized using the response surface methodology. The extraction yield and the total polyphenols were set as response values for the methodology. Quantitative factors in the extraction process were the extraction time, volume ratio of alcohol/ultrapure water, and extraction temperature. When considering both the main and interaction effects, the greatest influence factor on the extraction yield and total polyphenols was the extraction time. The optimum extraction time and temperature and alcohol/ultrapure water volume ratio for angelica were 2.8 h, $56.6^{\circ}C$ and 64.0 vol% respectively. The extraction yield and total polyphenols when using the conditions were calculated to be 24.6% and 8.76 mg GAE/g. respectively. Determination coefficients of regression equations for the extraction yield and total polyphenols were 81.4 and 75.4%, respectively. Also the overall satisfaction level was found to be 0.80 and the significance was confirmed within 5%.