• 한국생활과학회지
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• 제9권3호
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• pp.271-281
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• 2000

The purpose of this study was to explore the effect of maternal perception of children's temperament on parenting stress. The subjects of this study were 303 mothers of four to six-year-old. Evaluations of Parent and Teacher temperament questionnaire for Children 3-7 years of age(Tomas, Chess, & Kom, 1977)(korean version) was used to measure children's temperament, and PDH(Parenting Daily Hassles) was used to measure maternal perception of parenting stress. Data were analyzed by descriptive analysis, t-test, ANOVA, Peasons's Correlation and multiple regression analysis and Duncan test for post test by SPSS WIN program. The results of this study were as follows; First, the average level of maternal perception of children's temperament was the highest in the category of adaptability and the lowest in the category of threshold of responsiveness. Second, maternal perception of children's temperament was significantly different according to children's sex. Boys were perceived higher than girls for the category of activity level. Third, the degree of daily hassles was explained by adaptability, the quality of mood, and activity level relatively, while the intensity of parenting stress could be predicted orderly by adaptability, threshold of responsiveness, attention span & persistence, regularity, and activity level. Fourth, mother's daily hassles was explained 22% valiance by children's temperament such as adaptability, the quality of mood, and activity level. Future research should be done to identify the interaction of temperamental factors.

• 한국항공운항학회지
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• 제21권1호
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• pp.62-67
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• 2013

Human Powered Aircraft (HPA) should be light in weight and have high efficiency because power source of propulsion is human muscles. Airframe structure takes up most of empty weight of aircraft, so weight reduction of structure is very important issue for HPA. In this paper, design/analysis/test procedures for ultra light weight structure of the HPA developed by Korea Aerospace Research Institute (KARI) are explained briefly. Structural design is conducted through case studies on HPA in the USA and Japan. Loads analysis is performed to calculate design loads which is needed for structural design and analysis. Structural analysis is conducted for structure sizing. Static strength test of main wing spar which is primary structure of wing is performed to verify structural integrity.

• Journal of Korean Dental Science
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• 제7권2호
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• pp.80-86
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• 2014

Purpose: Current common method of cytotoxicity evaluation for elastomeric impression materials use animal based cell lines, which the clinical relevance has been often questioned. Hence, the purpose of this study was to examine the difference in results with both human based and animal based fibroblast cell line. Materials and Methods: Three types of fibroblast cells were used in this study; conventional mouse fibroblasts of L929, human gingival fibroblasts (HGF-1), and immortalized human oral fibrobalsts (hTERT-hNOF). Test on extract and test by direct contact using different commercially available elastomeric impression materials were carried out according to the international standards. Result: There was significant difference in cell viability between types of fibroblasts cell used, where HGF-1 showed highest cell viability and L929 the lowest. Conclusion: Within the limitation of this study, careful consideration must be given when selecting the cells and interpreting the results for cytotoxicity evaluation of elastomeric impression materials, where use of human based cell lines such as hTERT-hNOF would be appropriate for both ease of cytotoxicity test and clinical relevance.

• Journal of Periodontal and Implant Science
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• 제27권4호
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• pp.909-922
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• 1997

The purpose of this study was to evaluate the effect of high glucose on prostaglandin E2 production in human gingival fibroblasts and periodontal ligament cells in vitro. In control group, the cells($5{\times}10^4\;cells/ml$) were cultured with Dulbecco's Modified Eagle's Medium contained with 10% fetal bovine serum, 45mg/dl glucose. In experimental groups, glucose was added to the above culture condition at the final glucose concentrations of 100mg/dl(Test group 1), 200mg/dl (Test group 2) and 400mg/dl (Test group 3). Then each group was tested for the cell proliferation rate, protein levels, and prostaglandin E2 production at $\frac{1}{2}$, 1, 2, 5 days. The results were as follows : 1. As glucose concentration increased, cell proliferation rate decreased significantly at 1, 2, 5 days in human gingival fibroblasts and periodontal ligament cells(P<0.01). 2. In human gingival fibroblasts, test group 2 and 3 showed significantly decreased protein levels as compared to control group at 5 days (P<0.01). 3. In human periodontal ligament cells, as glucose concentration increased, protein levels decreased significantly at 2 days and 5 days(P<0.01). 4. Prostaglandin $E_2$ production in human gingival fibroblasts and human periodontal ligament cells significantly increased as glucose concentration increased(P<0.01). results at 5 days showed obvious difference as compared to those at 2 days. From the above results, high glucose appeared to affect cellular activities including cell proliferation rate, protein levels and enhance prostaglandin $E_2$ production. It was assumed that prostaglandin E2 production by high glucose enhances inflammatory reaction and has a toxic effect on human gingival fibroblasts and human periodontal ligament cells. This study suggests that periodontal disease in diabetic patient is related to prostaglandin $E_2$ production.

• 한국미생물·생명공학회지
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• 제49권2호
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• pp.249-254
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• 2021

The study of the impact of weather on viral respiratory infections enables the assignment of causality to disease outbreaks caused by climatic factors. A better understanding of the seasonal distribution of viruses may facilitate the development of potential treatment approaches and effective preventive strategies for respiratory viral infections. We analyzed the incidence of human mastadenovirus infection using real-time reverse transcription polymerase chain reaction in 9,010 test samples obtained from Cheonan, South Korea, and simultaneously collected the weather data from January 1, 2012, to December 31, 2018. We used the data collected on the infection frequency to detect seasonal patterns of human mastadenovirus prevalence, which were directly compared with local weather data obtained over the same period. Descriptive statistical analysis, frequency analysis, t-test, and binomial logistic regression analysis were performed to examine the relationship between weather, particulate matter, and human mastadenovirus infections. Patients under 10 years of age showed the highest mastadenovirus infection rates (89.78%) at an average monthly temperature of 18.2℃. Moreover, we observed a negative correlation between human mastadenovirus infection and temperature, wind chill, and air pressure. The obtained results indicate that climatic factors affect the rate of human mastadenovirus infection. Therefore, it may be possible to predict the instance when preventive strategies would yield the most effective results.

• 한국의류학회지
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• 제23권1호
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• pp.3-13
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• 1999

This study was performed for purpose of getting fundamental information requisite to wear velvet clothes that is more comfortable for the human body and also the environment. It was carried out in a human wearing test and thermal manikin test at the same time in a controlled-condition chamber. The experimental environment had a ambient temperature of 15$\pm$0.5$^{\circ}C$ with the relative humidity at 5$^{\circ}C$$\pm$5% and with air velocity at less that than 0.2m/sec. Velvet differ from common plain weaves in thermal properties because it's constructed in two parts one is ground part and the other part is pile part. In order to investigate the thermal resistance of velvet eight different combination of 4 velvet kinds and 2 lings kinds as experimental clothes. [(4 velvet kinds : Acetate cuprammoium Rayon Cotton Wool) (2 lining kinds : acetate viscose rayon)longrightarrow8 combination: Aa, Av, Ra, Rv, Ca, Cv, Wa, Wv: the simplified character] The results of this study can be summarized as follows : 1. For the regional thermal resistance the differences in eight clothes as well as differences in each part were significant. As a whole the breast part showed the highest thermal resistance and the leg part was higher than the shank part. The rank of the total thermal resistance was put at Wa>Wv>Ca>Cv>Aa>Av>Ra>Rv in this order. 2. Considered clothing microclimate microclimate temperature has a similar tendency to the total thermal resistance. It showed a significance in the differences of eight clothes and each parts. the belly part was highest in every combination. On the other hand for clothing humidity there was a significance between back and breast part only in the human wearing test. 3. It was indicated that CLO value was highly positively correlated with the clothings' weight and showed a high negative correlation with the air permeability.

• Environmental Analysis Health and Toxicology
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• 제29권
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• pp.4.1-4.10
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• 2014

Objectives Effects of nanoparticles including zinc oxide nanoparticles, titanium oxide nanoparticles, and their mixtures on skin corrosion and irritation were investigated by using in vitro 3D human skin models ($KeraSkin^{TM}$) and the results were compared to those of an in vivo animal test. Methods Skin models were incubated with nanoparticles for a definite time period and cell viability was measured by the 3-(4, 5-dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide method. Skin corrosion and irritation were identified by the decreased viability based on the pre-determined threshold. Results Cell viability after exposure to nanomaterial was not decreased to the pre-determined threshold level, which was 15% after 60 minutes exposure in corrosion test and 50% after 45 minutes exposure in the irritation test. IL-$1{\alpha}$ release and histopathological findings support the results of cell viability test. In vivo test using rabbits also showed non-corrosive and non-irritant results. Conclusions The findings provide the evidence that zinc oxide nanoparticles, titanium oxide nanoparticles and their mixture are 'non corrosive' and 'non-irritant' to the human skin by a globally harmonized classification system. In vivo test using animals can be replaced by an alternative in vitro test.

• 대한화장품학회지
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• 제17권1호
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• pp.64-80
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• 1991

The SKINTEX Method is based on a two-compartment physico-chemical model which includes a Biomembrane Barrier in compartment one and an organized macromolecular matrix in compartment two. Test samples absorb onto or permeate through the keratin/collagen Biomembrane Barrier and then can interact with the organized macromolecular matrix. Changes in the integrity of the barrier release a dye indicator: Changes in the matrix can alter its transparency. The sum of these two responses is read spectrophotometrically at 470nm. An early investigation of 950 chemicals and formulations in the SKINTEX System produced results which were 89% concordance to in vivo Draize dermal irritation results obtained with 24-hour occluded application of test samples with-out abrasion and standard scoring. Alkaline materials were analyzed in a specialized SKINTEX AMA Protocol. In this early study, the model did not distinguish nonirritant test materials and formulation with PDII(Primary Dermal Irritation Index)in the range from 0 to 1.2, A High Sensitivity Assay Protocol(HSA)was developed to amplify the changes in both compartments of this model and provide more accurate calibration of these changes. A study of 60 low irritation test samples including cosmetics, household products, chemicals and petro-chemicals distinguished nonirritants with PDII $\leq$ 0.7 for 26 of 30 nonirritants. A second protocol was developed to evaluate the SKINTEX model predictability with respect to human irritation. The Human Response Assay (HRA )has been optimized based on differences in penetration and irritation responses in humans and rabbits. An additional 32 test materials with different mechanisms and degrees of dermal toxicity were evaluated by the HRA. These in vitro results were 86% concordant to human patch test results. In order to further evaluate this model, a Standard Chemical Labelling (SCL) Protocol was developed to optimize this system to predict Draize dermal irritation results after a 4-hour application of the test material. In a study of 52 chemicals including acids, bases, solvents, salts, surfactants and preservatives, the SCL results demonstrated 85% concordance to Draize results for a 4-hour application of test samples on non-abraded rabbit skin. The SKINTEX System, including three specialized protocols, provided results which demonstrated good correlation to the endpoint of dermal irritation in man and rabbits at different application times.

• Clinical and Experimental Reproductive Medicine
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• 제12권1호
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• pp.41-46
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• 1985

Various immunoserologic and cellular immunity techniques have been used to explore the presence of antisperm antibodies in the serum and seminal plasma of male patients and in the blood and genital fluid of infertile women. Several recent comparative investigations using various assays to detect and quantitate levels of antibody to human spermatozoa have produced widely varying results. So the first WHO workshop on iso- and autonatibodies to human spermatozoa in 1974 tried to establish some unification in the techniques used. The purpose of this study is to compare the results of two methods-the Kibrick macro-agglutination test and the Isojima micro-immobilization test-using the same test materials based on recommandation from WHO workshop. The results are as follows: 1. Twenty normal controls showed negative reactions in all the 2 tests. Out of 25 patients, the positive sera were noted in 15 (60%) on the Kibrick test and 13 (51%) on the Isojima test. 2. Twelve (48%) out of 25 patients showed positive reactions in the two tests, and 16 (64%) out of 25 patients showed positive reaction in one or more tests. 3. The titers of the antisperm antibodies on the Kibrick test was higher than that on the Isojima test. Therefore, it seems to be possible to increase the chances of detection of the antisperm antibodies, if two tests are imployed.

• 한국신뢰성학회지:신뢰성응용연구
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• 제6권3호
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• pp.205-212
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• 2006

The purpose of this article is about the accelerated product-reliability-test method of the changing colors of mobile products, which are majorly from the frequent touching of sweating fingers. Such problems of changing colors of mobile products have found mostly In metallic paint containing aluminum paste pigments. Also we found that the color of Al Paste is changed by human sweat. Therefore, the accelerated experimental method has been tested as follow: applying the various concentration of lactic acid, which is the changing color components from human sweat, and deeping the testing sample under temperature of $60^{\circ}C$ in dilutelactic acid with water. From the series of tests, the most optimum concentration of lacticacid has been obtained in 10wt% and the sample is observed to be almost same effect as natural changing of colors by human touching after the test. It has been also confirmed from the cross-sectional analysis. In detail, the testing sample has changed its color in 48hr by changing color effect of Alpaste with 10 wt% of lactic acid, and the digit of $\Delta$ E has measured 10.9 after the test.