• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05b
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• pp.1-19
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• 2002

It is well established that the initiating event in chemical carcinogenesis is the binding of reactive carcinogens to DNA. Thus, a number of analytic methods have been developed for determining levels of carcinogen-DNA adducts in humans as a marker of individual exposure and, potentially, of risk for cancer development. In addition, reactive carcinogens also bind to protein suggesting protein adducts can be used as a surrogate for DNA adducts in some situations. We have developed monoclonal and polyclonal antibodies to carcinogen-DNA and protein adductis and highly sensitive ELISA and immunohistochemical assays for determining levels of adducts in human tissues. These studies have demonstrated higher levels of adducts in those with higher exposure as a result of workplace, dietary, chemotherapy, environmental of lifestyle (smoking) exposures. Elevated levels of adducts have been found in lung and liver cancer cases compared to controls. We have also used DNA adducts to determine efficacy of an antiosidant vitamin intervention. DNA adduct studies have demonstrated very different levels of damage in those with similar exposure levels. These interindividual differences are likely the result genetic differences in capacity to activate carcinogens, detoxify reactive intermediates and repair DNA adducts once formed. We are currently investigating the relationship between polymorphisms in a number of these genes to determine their relationship to adduct levels as well as their ability to confer increased risk for cancer development. The ability to identify high risk individuals will allow the targeting of screening and preventive strategies to those most likely to benfit.

• Journal of Nutrition and Health
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• v.30 no.5
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• pp.478-488
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• 1997

Omega-3 fatty acid, docosahexaenoic acid(DHA) is found in a high proportion in the structural lipids of cell membranes, in particular those of the central nervous system and the retina. Diet-induced changes in fatty acid composition in these tissues may affect physiochemical functions. This study was conducted to investigate whether supplements of DHA in infant formula has an effect on the composition of fatty acids in erythrocytes with regard to brain development. Experimental groups were breastmilk group(n=21), placebo formula group(n=15), and DHA supplemented formula (0.26%) group(n=16). Infants were selected by mothers who deliverecdd at Kyung Hee medical center from February to April, 1996. Infant body weight, length, and head circumference were similar among the experimental groups at 16 weeks of age. The levels of DHA in breastmilk, placebo formula, and DHA supplemented formula were 0.56, 0, and 0.26% of total fatty acids, respectively. There was a significant correlation between dietary DHA intake and erythrocyte DHA levels. The levels of arachidonic acid did not differ among the three expermental groups. The result of flash visual evoke potential(VEP) test was correlated with the erythrocyte levels and dietary DHA levels at 16 weeks of age. No other fatty acid was correlated with VEP test results. No differences were found in Bayley Mental and Psychomotor Development Index scores among the three groups at 20 weeks of age. DHA seems to be an essential nutrient for optimum growth and maturation of term infants. Relatively small amounts of dietary DHA supplementation significantly elevate DHA supplementation significantly elevate DHA content in erythrocytes, which in turn has an implication for better scores for infant's VEP test. Whether supplementation of formula-fed infants with DHA has long-term benefits remains to be elucidated.

• Molecules and Cells
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• v.27 no.1
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• pp.15-19
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• 2009

Notch signaling is controlled at multiple levels. In particular, stabilized Notch receptor activation directly affects the transcriptional activations of Notch target genes. Although some progress has been made in terms of defining the regulatory mechanism that alters Notch stability, it has not been determined whether Notch1/NICD stability is regulated by $GSK-3{\alpha}$. Here, we show that Notch1/NICD levels are significantly regulated by $GSK-3{\beta}$ and by $GSK-3{\alpha}$. Treatment with LiCl (a specific GSK-3 inhibitor) or the overexpression of the kinase-inactive forms of $GSK-3{\alpha}/{\beta}$ significantly increased Notch1/NICD levels. Endogenous NICD levels were also increased by either $GSK-3{\alpha}/{\beta}$- or $GSK-3{\alpha}$-specific siRNA. Furthermore, it was found that $GSK-3{\alpha}$ binds to Notch1. Deletion analysis showed that at least three Thr residues in Notch1 (Thr-1851, 2123, and 2125) are critical for its response to LiCl, which increased not only the transcriptional activity of endogenous NICD but also Hes1 mRNA levels. Taken together, our results indicate that $GSK-3{\alpha}$ is a negative regulator of Notch1/NICD.

• Reproductive and Developmental Biology
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• v.37 no.4
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• pp.219-224
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• 2013

Muscular satellite cell (SC), which is stem cell of postnatal pig, is an important for study of differentiation into adipogenesis, myogenesis, and osteoblastogenesis. In this study, we isolated and examined from pig muscle tissue to determine capacity in proliferate, differentiate, and expression of various genes. Porcine satellite cells (PSC) were isolated from semimembranosus (SM) muscles of 90~100 days old pigs according to standard conditions. The cell proliferation increased in multi-potent cell by Masson's, oil red O, and Alizarin red staining respectively. We performed the expression levels of differentiation related genes using real-time PCR. We found that the differentiation into adipocyte increased expression levels of both fatty acid binding protein 4 (FABP4) and peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) genes (p<0.01). Myocyte increased the expression levels of the myosin heavy chain (MHC), myogenic factor 5 (Myf5), myogenic regulatory factor (MyoD), and Myogenic factor 4 (myogenin) (p<0.01). Osteoblast increased the expression levels of alkaline phosphatase (ALP) (p<0.01). Finally, porcine satellite cells were induced to differentiate towards adipogenic, myogenic, and osteoblastogenic lineages. Our results suggest that muscle satellite cell in porcine may influence cell fate. Understanding the progression of PSC may lead to improved strategies for augmenting meat quality.

• Korean Journal of Child Studies
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• v.37 no.3
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• pp.1-12
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• 2016

Objective: This study aimed to examine the difference in toddlers' accumulated cortisol levels based on childcare experience in toddlerhood and the relationship between temperament and accumulated cortisol levels. Methods: Hair sample were collected for measure accumulated cortisol level in 87 toddlers. The Early Childhood Behavior Questionnaire (ECBQ) was used to measure temperament. Results: First, toddlers in childcare showed higher accumulated cortisol levels than in-home toddlers. Second, toddlers in childcare, exhibited a significant correlation between accumulated cortisol levels and surgency. Third, the accumulated cortisol levels of in-home toddlers exhibited a significant correlation with negative affect. In this research, there was significant range in the accumulated cortisol level according to childcare use, and the factors related to accumulated cortisol levels were different in each context. Conclusion: The results of this research support the "susceptibility to context of HPA axis" and imply a needed discussion about the effect of childcare experiences in toddlerhood.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.39
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• pp.163-170
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• 1996

Several formerly independent trends including the increasing rate of technological change, the demand for greater efficiency and productivity in R&D and innovation. The purpose of this study is describe performance evaluation of research and development. Performance evaluation level of R&D have three levels: individual level, research group level, laboratory level. There are development evaluation factors and evaluation routin in each levels.

• Korean Journal of Child Studies
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• v.32 no.5
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• pp.151-165
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• 2011

The purpose of this study was to examine the relationship between the information literacy of preschoolers and their developmental trends. The subjects in this study were 122 preschoolers. After taking tests in information literacy and early childhood development, the collected data was analyzed. The findings of the study were as follows : First, there were gaps among the preschoolers in the level of early childhood development according to the relative levels of their information literacy. When a post-hoc analysis was carried out to investigate intergroup differences in detail, there were statistically significant gaps between the preschoolers with excellent information literacy and those with intermediate-or poor information literacy, and between the preschoolers with intermediate information literacy and those with poor information literacy. Second, the differences in terms of the levels of information literacy and the impact these differences made to their body, cognition, language, sociability and emotions which comprise the five subfactors of the early childhood development inventory were checked after the mutual influence of the five subfactors was controlled. As a result, statistically significant gaps were apparent in all the subfactors of early childhood development according to relative levels of information literacy. The preschoolers who had a better level of information literacy exhibited a statistically significantly better level of development in every subfactor.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.5
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• pp.309-314
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• 2008

The toxicity of five species of puffer fish, Arothron firmamentum (Byeolbok), Lagocephalus gloveri (Heukmilbok), L. wheeleri (Eunmilbok), L. inermis (Minmilbok) and L. lunaris (Milbok), collected from fish markets in Korea, was determined using a mouse bioassay. In A. firmamentum, the proportion of toxic specimens containing >10 MU/g was 87.5% in the ovaries, and 10.0% in the skin; no toxicity was detected in the muscle, fin, liver, intestine and gallbladder using the mouse bioassay. The highest toxin levels were found to be 87 MU/g in the ovaries, and 13 MU/g in the skin. Toxic specimens containing >10 MU/g were not detected from samples taken from any of the organs in L. wheeleri and L. inermis. In L. gloveri, most specimens were found to be non-toxic, but toxin levels of 11-72 MU/g were detected from within the skin, fins, and intestines in one specimen. In L. lunaris, the proportion of toxic specimens was 50.0% in the ovaries, and 7.1% in the gallbladder; no toxicity was detected in the other organs by the mouse bioassay. The highest toxin levels were 75 MU/g in the ovaries, and 14 MU/g in the gallbladder. Therefore, the toxicities of edible muscle and skin in the five species of puffer fish marketed in Korea were found to be within acceptable levels for human consumption.

• Journal of Digital Convergence
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• v.17 no.6
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• pp.27-33
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• 2019

The purpose of this study was to explore the moderating effect of learning strategy levels on the relationship between academic grit and career development competence perceived by high school students. The sample for this study comprised 573 high school students, and data analysis was conducted mainly using reliability analysis, correlation analysis, K-mean cluster analysis, hierarchical regression analysis. The results of the study showed that the learning strategy levels moderated the relationship between academic grit and career development competence. This study suggest it is necessary to provide grit enhancement programs coupled with learning strategy levels in order to facilitate career development competence. The future studies need to explore the literature review for logical relationship between academic grit and career development competence, the qualitative approach for drawing on the theoretical models among the related variables, and the relational research to explore mediating or moderating effect of the individual backgrounds and related variables on the relationship between academic grit and career development competence.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.4
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• pp.239-249
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• 2013

The role of software process is getting more important to make good quality softwares. One of the measures to improve the software process is Defect Removal Efficiency(DRE). DRE gives a measure of the development team ability to remove defects prior to release. It is calculated as a ratio of defects resolved to total number of defects found. Software Engineering Levels are usually decided by CMMI Model. The model is designed to help organizations improve their software product and service development, acquisition, and maintenance processes. The score of software engineering levels can be calculated by CMMI model. The levels are composed of the three groups(absent, average, and advanced). This study is to find if there is any difference among the three categories in term of the result of software engineering levels on DRE. We propose One way ANOVA to analyze influence of software engineering levels on DRE. Bootstrap method is also used to estimate the sampling distribution of the original sample because the data are not sampled randomly. The method is a statistical method for estimating the sampling distribution of an estimator by sampling with replacement from the original sample. The data were collected in 106 software development projects by the survey. The result of this study tells that there is some difference of DRE among the groups. The higher the software engineering level of a specific company becomes, the better its DRE gets, which means that the companies trying to improve software process can increase their good management performance.