• Korean Journal of Environmental Biology
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• v.29 no.1
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• pp.61-67
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• 2011

N-acetyl-L-cysteine (NAC) having a thiol, a precursor for glutathione (GSH), is known as one of the antioxidants. NAC used as a radioprotector against ionizing radiation (IR)-induced injury and damage. The aim of this study was to evaluate the radioprotective effects of NAC against IR-induced cell damage in Saccharomyces cerevisiae and the antioxidative effect of NAC on transcriptional level of yeast antioxidant enzyme genes such as superoxide dismutase (SOD) and catalase. In the present study, yeast cells were pretreated with various concentrations of NAC and/or irradiated with various doses of gamma rays. The cell viability was measured by counting the cell forming unit (CFU). The quantitative real-time PCR was performed for analysis of gene expression of SOD and catalase. The viability of irradiated cells was not improved by pretreatment with NAC. Ionizing radiation with 100 Gy highly induced the gene expression of antioxidant enzymes. In the irradiated group with NAC pretreatment, the gene expression of SOD and catalase was gradually reduced with the increased concentrations of NAC. These results indicate that NAC can act as a useful antioxidant to scavenge reactive oxygen species in vivo, but does not protect cells against IR-induced cell death in S. cerevisiae.

• Journal of Engineering Education Research
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• v.10 no.1
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• pp.60-76
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• 2007

In this study, the effect of a sustainable energy design project on academic achievement for engineering freshmen at Virginia Tech in fall semester 2006 in the United States was examined by experimental method. The department of engineering education at Virginia Tech was opened in 2004. In this experiment the population was approximately 1200 freshmen, and 5 classes were sampled. Subject name is engineering exploration, a theme of the instruction is sustainable energy design, the project was performed throughout a 6 weeks period with one by 50 minutes lecture conducted by faculty and one 90 minutes workshop conducted by GTAs (Graduate Teaching Assistants) every week. The statistical results using SPSS (ver. 15.0) are as follows: A paired-samples t test analysis was run on the pre- and posttest to determine academic achievement, the results indicated a significant increase in 4 classes of mixed gender at .05 significance level, but there was no significance at 1 group of female class. A paired-samples t test analysis was run on the pre- and posttest to get an attitude score, the results showed, the posttest scores decreased for 5 groups even though it was not statistically significant. Finally, in responses to an open-ended question about students' perceptions of their improvement in skills, the 3 most frequently identified skills were teamwork, design process, knowledge.

• Journal of Gifted/Talented Education
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• v.20 no.1
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• pp.107-130
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• 2010

The purpose of this study is to investigate the characteristics that indicate scientifically gifted students by analyzing the verbal interactions in developmental biology inquiry-experimental classes. The subjects were 20 first-grade middle school students who were participating in SNU Science Gifted Education Center. In these experimental classes which were developed based on the CPS Model, we conducted a total of four experimental sessions of small group discussions, and the students' verbal interactions were both taped and video recorded, and observed. From the transcriptions, the patterns of question-answer and the characteristics of scientifically gifted students were analyzed. In the case of question-answer patterns, thinking questions appeared 3~6 times more frequently than the standard information questions. Especially, the case of experimental class I showed 40% more thinking questions as well as standard information questions that the other 3 classes. Through the results of analysing verbal interactions, we were able to find more detailed aspects to creativity that were not identifiable in paper-pencil examinations, as well as affective characteristics such as task commitment and leadership. We believe our findings upon inquiry will be of substantial significance in substituting for the paper-pencil examination in distinguishing and selecting scientifically gifted students.

• Journal of Korean Home Economics Education Association
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• v.16 no.4 s.34
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• pp.43-56
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• 2004

The purpose of this study was to develop the web-based practical problem-solving teaching plans for middle school home economics class. Five practical problems which were obesity, food waste, processed food, genetically-modified food, and imported food were selected based on the food, nutrition and diet of adolescent in middle school home economics syllabus. Web-based practical problem-solving teaching plans were consisted of 5 processes: 1)recognition of the practical problem, 2)gathering and evaluation of various information, 3)figure out the best way to tackle the practical problem, 4)put into behavioral practice, and 5)analyze the results of the behavioral practice. For the effective lesson, several supplemental materials, such as individual and group reports format. obesity test methods, animations. pictures, and modules were developed. Teaching plans including supplemental materials provided might be useful to middle school home economics teachers.

• Journal of The Korean Association For Science Education
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• v.35 no.5
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• pp.895-905
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• 2015

Citizens should be sensitive to the complex and controversial SSIs (Socioscientific Issues), be able to make a responsible decision with evidence and empathy, and furthermore take political action for the larger welfare. The premise of this research is that understanding the nature of science (NOS) takes an important role when students and adults participate in the discourse on SSIs because SSI reasoning requires individuals to examine information and counter-information with skepticism. We therefore designed SSI programs that were incorporated with NOS by adapting a contextualized-reflective approach. The leading research question was to what extent SSI contexts contributed to promoting students' understanding of NOS. A total of 71 11th grade students participated in this program. The school was located in an urban city near the capital city of Seoul, South Korea. We designed SSI programs to cover the issues of genetically modified organisms, climate change, and nuclear energy. Each issue required four to six class periods to complete. We conducted pre- and post-program tests using the revised VNOS-C, recorded group discussions or debates and collected student worksheets to observe the increase of student NOS understanding. As a result of this program, students showed moderate improvement in their understanding of NOS.

• Journal of The Korean Association For Science Education
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• v.35 no.5
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• pp.877-884
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• 2015

Technology is an important means to enhance students' understanding about scientific concepts. In particular, newly introduced 3D printing technology has great potential to help students learn scientific concepts better. 3D printing is a process for a creating physical object with a three dimensional model. In this study, we explored two types of learners' (students vs. adults) motivation and satisfaction with 3D printing technology. With regard to motivation, student learners showed higher task value, self-efficacy for learning, and satisfaction than adult learners. The result implied that 3D printing technology is more effective to student learners than adult learners. In addition, for adult learner group, negative relationship between technology and satisfaction was found. Therefore, support for reducing the technology anxiety for adult learners is necessary. Further discussions are provided for the research and application of 3D printing technology in science classroom.

• Clinical and Experimental Reproductive Medicine
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• v.23 no.3
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• pp.269-275
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• 1996

Biosynthesis and secretion of anterior pituitary hormones are under the control of specific hypothalamic stimulatory and inhibitory factors. Among them, Growth Hormone Releasing Hormone (GHRH) is the major stimulator of pituitary somatotrophs activating GH gene expression and secretion. Human GHRH is a polypeptide of 44 amino acids initially isolated from pancreatic tumors, and the gene for the hypothalamic form of GHRH is organized into 5 exons spanning over 10 kilobases (kb) on genomic DNA and encodes a messenger RNA of 700-750 nucleotides. Several neuropeptides classically associated with the hypothalamus have been found in the extrahypothalamic regions, suggesting the existence of novel sources, targets and functions. GHRH-like immunoreactivity has been found in several peripheral sites, including placenta, testis, and ovary, indicating that GHRH may also have regulatory roles in peripheral reproductive organs. Furthermore, higher molecular weight forms of the GHRH transcripts were identified from these organs (1.75 kb in testis; 1.75 and >3 kb in ovary). These tissue-specific expression of GHRH gene suggest the existence of unique regulatory mechanism of GHRH expression and function in these organs. In fact, placenta-specific and testis-specific promoters for GHRH transcripts which are located in about 10 kb upstream region of hypothalamic promoter were reported. The use of unique promoters in extrahypothalamic sites could be refered in a different control of GHRH gene and different functions of the translated products in these tissues. Somatotrophs and lactotrophs have been thought to be derived from a common bipotential progenitor, the somatolactotrophs, which give origins to either phenotypes. Although the precise mechanism responsible for the lactotroph differentiation in the anterior pituitary gland has not been yet clalified, there are several candidators for the generation of lactotrophs. In human, the presence of GHRH peptides with different size from authentic hypothalamic form in the normal anterior pituitary and several types of adenoma were demonstrated. Recently our group found the existence of immunoreactive GHRH and its transcript from the normal rat anterior pituitary (gonadotroph> somatotroph> lactotroph), and the GHRH treatment evoked the increased proliferation rate of anterior pituitary cells in vitro. The transgenic mouse models clearly shown that GHRH or NGF overexpression by anterior pituitary cells induced development of pituitary hyperplasia and adenomas particularly GH-oma and prolactinoma. Taken together, we hypothesize that the pituitary GHRH could serve not only as a modulator of hormone secretion but as a paracrine or autocrine regulator of anterior pituitary cell proliferation and differentiation. Interestingly enough, the expression of Pit-1 homeobox gene (the POU class transcription factor) was confined to somatotrophs, lactotrophs and somatolactotrophs in which GHRH receptors are expressed commonly. Concerning the mechanism of somatolactotroph and lactotroph differentiation in the anterior pituitary, we have focused following two possibilities; (1) changes in the relative levels or interactions of both hypothalamic and intrapituitary factors such as dopamine, VIP, somatostatin, NGF and GHRH; (2) alterations of GHRH-GHRH receptor signaling and Pit-1 activity may be the cause of lactotroph differentiation or pituitary hyperplasia and adenoma formation. Extensive further studies will be necessary to solve these complicated questions.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.489-498
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• 2016

The purpose of this study was to evaluate selective attributes importance and satisfaction of University Ski Lecture Environment that students perceive using IPA method. In order to achieve this goal, a questionnaire was used to gather data, and the convenient sampling method was used to select 300 members from three pertinent university in Seoul and Chungcheong-do, Gyeongsang-do Province as participants of this study. Only data from 221 respondents however were used after screening data for reliability, and SPSS for Windows(21.0 version) statistical program was used to conduct descriptive analysis, factor analysis, reliability analysis, paired samples t-test analysis, independent samples t-test analysis and IPA matrix analysis. The following results were obtained. First, significant differences between the level of satisfaction and the level of importance were found for part of the selection attributes for each group. Second, Iquadrant was included with meals and information provided factors. IIquadrant was included with instructors and class program, information provided, accommodation factors. IIIquadrant was included in accommodation and meals, time-distance factors. IVquadrant was included in the information provided factor.

• Korean Journal of Environment and Ecology
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• v.32 no.2
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• pp.176-184
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• 2018

This study was intended to provide basic data for more ecological and systematic preservation and management planning of forest vegetations in the Baekdudaegan sector between Danmoknyeong and Guryongnyeong where biodiversity is considered to be very important. A vegetation survey using the Zurich-Montpellier (Z.-M.) method of phytosociology was carried out in a total 142 sites to examine the environmental characteristics. The survey showed the forest vegetation types of one community group, two communities, four groups, and four subgroups. Quercus mongolica and Acer pseudosieboldianum, which fall under Constancy Class V, were dominant species and deemed to be the key species of the forest ecosystem management plan for the investigated areas. Regarding species diversity, it was found that the dominant species of the VT3 type were evenly distributed in the area while the species of the VT4 type showed not only a diverse composition but also the most abundant number of species. Moreover, there were 24 of rare plants found in the Danmoknyeong-Guryongnyeong section: the critically endangered species include Dracocephalum rupestre; the endangered species include Saxifraga octopetala; the vulnerable species include Paeonia japonica, Euphorbia fauriei, Hanabusaya asiatica, and Parasenecio pseudotaimingasa; the least concern species include Aristolochia manshuriensis, Rodgersia podophylla, Salvia chanryoenica, Scopolia japonica, and Parasenecio firmus.

• Journal of Digital Convergence
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• v.13 no.7
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• pp.33-45
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• 2015

Present study aims to describe who are the non-regular female workers in South Korea. The dominant form of employment of Korean female non-regular workers is characterized by instable contract, low wage, long-time work and exclusion from the state and occupational welfare. Also, non-regular female workers are not homeogenous but there are various groups of women among female non-regular workers including young part-time workers, high educational middle class contract professionals, particular contract workers such as home-schooling teachers. However, it would worth noting that over 40s, low-educational, low income, breadwinning women who are working in sales, service, and simple handy job are most likely to become non-regular female workers in South Korea. Those women are the major group among non-regular female workers. The public assistance (in cash) for non-regular workers are necessarily needed for them at this point in South Korea.