• Journal of Ginseng Research
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• v.46 no.1
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• pp.104-114
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• 2022

Background: Abnormalities of myelin, which increases the efficiency of action potential conduction, are found in neurological disorders. Korean Red Ginseng (KRG) demonstrates therapeutic efficacy against some of these conditions, however effects on oligodendrocyte (OL)s are not well known. Here, we examined the effects of KRG-derived components on development and protection of OL-lineage cells. Methods: Primary OL precursor cell (OPC) cultures were prepared from neonatal mouse cortex. The protective efficacies of the KRG components were examined against inhibitors of mitochondrial respiratory chain activity. For in vivo function of Rb1 on myelination, after 10 days of oral gavage into adult male mice, forebrains were collected. OPC proliferation were assessed by BrdU incorporation, and differentiation and myelination were examined by qPCR, western blot and immunocytochemistry. Results: The non-saponin promoted OPC proliferation, while the saponin promoted differentiation. Both processes were mediated by AKT and extracellular regulated kinase (ERK) signaling. KRG extract, the saponin and non-saponin protected OPCs against oxidative stress, and both KRG extract and the saponin significantly increased the expression of the antioxidant enzyme. Among 11 major ginsenosides tested, Rb1 significantly increased OL membrane size in vitro. Moreover, Rb1 significantly increased myelin formation in adult mouse brain. Conclusion: All KRG components prevented OPC deaths under oxidative stress. While non-saponin promoted proliferation, saponin fraction increased differentiation and OL membrane size. Furthermore, among all the tested ginsenosides, Rb1 showed the biggest increase in the membrane size and significantly enhanced myelination in vivo. These results imply therapeutic potentials of KRG and Rb1 for myelin-related disorders.

• Journal of Astronomy and Space Sciences
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• v.34 no.2
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• pp.75-82
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• 2017

High-resolution spectroscopic observations of the eclipsing binary system RR Lyn were made using the 1.8 m telescope at the Bohuynsan Optical Astronomical Observatory in Korea. The spectral resolving power was R = 82,000, with a signal to noise ratio of S/N > 150. We found the effective temperatures and surface gravities of the primary and secondary components to be equal to $T_{eff}$ = 7,920 & 7,210 K and log(g) = 3.80 & 4.16, respectively. The abundances of 34 and 17 different chemical elements were found in the atmospheric components. Correlations between the derived abundances with condensation temperatures and the second ionization potentials of these elements are discussed. The primary component is a typical metallic line star with the abundances of light and iron group elements close to solar values, while elements with atomic numbers Z > 30 are overabundant by 0.5-1.5 dex with respect to solar values. The secondary component is a ${\lambda}$ Boo type star. In this type of stars, CNO abundances are close to solar values, while the abundance pattern shows a negative correlation with condensation temperatures.

• Journal of the Korean Chemical Society
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• v.46 no.4
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• pp.363-377
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• 2002

The purpose of this study was to improve the problems of the voltaic cell described in the science textbooks of secondary schools. For this purpose, the contents of science textbooks which are related to the voltaic cell were analyzed and the problems which were not explained clearly by theorems were tried to be explained by experiments, and lastly sug-gestions were made toward the improvements regarding the voltaic cell in the science textbooks. The findings are that there are problems on the ways of ensuring whether the voltaic cell operates properly as a chemical battery, on the explanation of why the hydrogen bubbles form at the zinc electrode, on the cell potential, on the unification of the electrode terminology used, and on the mention of the current. Solutions to the problems except the cell potential were suggested. According to the experiment, the theoretical potential was calculated by considering the potentials of redox reactions at the two electrodes of the cell and by taking into account the characteristics of the electrodes such as the work function, ionization energy, stan-dard reduction potential, and electronegativity.The cell potential of the voltaic cell is explained by several factors. In the improved version of the textbook's introduction section to the voltaic cell, it is necessary to describe the voltaic cell his-torically.For the conceptual section, it should be explained in terms of the Daniel cell.

• Journal of the Korean Wood Science and Technology
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• v.47 no.5
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• pp.607-616
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• 2019

On account of the lack of education of Brazilian worker, this paper analyzed the characteristics of those professionals working in the production sector of timber houses. A sectoral survey was carried out with respective entrepreneurs to investigate the available professionals (career and contract types), evaluate the demands of skilled workers, and indicate solutions to improve the quality of labor qualification. Similarly, over 65% of sampled producers presented both direct-hired and outsourced workforce. For such contract ways, Civil Engineers and Architects were the main careers. Carpenters, Civil Engineers and Architects experienced on timber were the main sectoral demands. Timber Engineers have good potentials of service for this sector. The creation of courses on timber products can emerge as a key alternative to train people.

• Journal of Astronomy and Space Sciences
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• v.37 no.3
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• pp.157-163
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• 2020

High resolution spectroscopic observation of V1719 Cyg were made at 1.8 meter telescope of Bohyunsan Optical Astronomy observatory in Korea. Spectral resolving power was R=45,000, signal to noise ratio S/N>100. The abundances of 28 chemical elements from carbon to dysprosium were found with the spectrum synthesis method. The abundances of oxygen, titanium, vanadium and elements with Z>30 are overabundant by 0.2-0.9 dex with respect to the solar values. Correlations of derived abundances with condensation temperatures and second ionization potentials of these elements are discussed. The possible influence of accretion from interstellar environment is not so strong as for ρ Pup and other stars with similar temperatures. The signs of accretion are absent. The comparison of chemical composition with solar system r- & s-process abundance patterns shows the enhancement of the photosphere by s-process elements.

• Journal of the Korean earth science society
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• v.41 no.2
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• pp.155-175
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• 2020

The purpose of this study is to analyze the 2015 revised Science Curriculum and Environment Curriculum, and to provide implications for the correlation and complementarity between the two standards. For the analysis of the curriculum, the contents system of the two standards was reorganized based on the four categories of knowledge, attitude, inquiry, participation and practice, which are common literacy elements of science and environment, based on previous studies. Content Analysis was performed on content elements and detailed performance expectation. As a result of this study, there was a difference in terms of the core competencies and goals. The Environment Curriculum emphasized sustainable development and social participation while the Science Curriculum emphasized scientific inquiry and literacy. The contents system analysis results according to the four literacy factors are as follows. First, in terms of attitude, both standards deal with research ethics in common. However Environment Curriculum values learners' values and views on the environment more than Science Curriculum which emphasizes the science attitude as science investigators. Second, there was a serious problem in the knowledge linkage between two standards. In same grade groups, the level of content knowledge dealt in two standards was not consistent. Third, in the inquiry aspect, the Environment Curriculum deals with interdisciplinary topics in the purposefully designed inquiry unit, whereas the Science Curriculum presents various research activities based on related science concepts in every unit. Fourth, in the participation and practice aspect, the Environment Curriculum focused on participation and practice while the Science Curriculum focused on sustainable science and technology development and improvement, scientific interest and decision-making ability. This study provide implications for education for sustainable development(ESD) by providing the complementary potentials between Science Curriculum and Environment Curriculum.

• Journal of Gifted/Talented Education
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• v.26 no.2
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• pp.299-318
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• 2016

The purpose of study was to explore science teachers' practical knowledge on teaching the gifted in science; namely, what kinds of instructional methods did they perceive as effective approaches based on their teaching experience with the gifted? Twelve science teachers who had 4-11 years of teaching experiences with the gifted students at the gifted center under the local educational offices participated in the study. The data source included in-depth individual interviews with the teachers. In results, the teachers became more aware of the academic potentials and characteristics of the students and had made efforts to develop their instructional methods more fitting to the characteristics and needs of the gifted. They emphasized four instructional aspects: 1) experience of authentic inquiry process and methods, 2) group activities focusing on leadership, communication and collaboration, and empathetic attitudes, 3) tasks promoting creative and convergent thinking, and 4) career awareness in the field of science, technology, and engineering. It is expected that this study provides more practical implications and insights for novice science teachers in the gifted education.

• Journal of Environmental Science International
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• v.18 no.2
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• pp.177-186
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• 2009

The changes in the worldwide paradigm of the sustainable development have started to be applied in the entire industry fields, and they come out as the sustainable tourism in the field of tourism. And the ecotourism has emerged as a practical method to meet the needs of the actual practice and the intellectual system for the sustainable tourism. In the type of tourists based on tourist attitude, 82.3% has the environment-friendly tourist attitude as a potential ecological tourist or an ecological tourist. In addition, there are the potentials of increase in ecological tourists as well as the revitalization of ecological tourism. First, the ecological tourists are mostly the well-educated and married professional workers at 40, housewives, and people earning a high income. Next, the potential ecological tourists are mainly the well-educated and married professional workers at 30, workers in the service industry, and middle-class citizens. Lastly, the general tourists are the students at 20 who are single, earn a low income, and has low level of education. This study presents useful data to the tourist business in terms of the development, operation and management of sustainable ecological tourism.

• Analytical Science and Technology
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• v.11 no.3
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• pp.151-155
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• 1998

Electrochemical behaviours on 1.0 mM methylviologen ($MV^{2+}$) in 100 mM NaCl+27 mM $MgCl_2$ solution, without and with sodium dodecyl sulfate (SDS), were studied. The intersection of two lines on ${\Delta}E_p$ (the difference between the anodic, $E_{pa}$, and the cathodic, $E_{pc}$, peak potentials) of the first and second redox waves vs. -log[SDS] plot was determined as a critical micelle concentration (CMC). When $Mg^{2+}$ was added, the effective access of $MV{\cdot}^+$ to the glassy carbon electrode surface became possible and the formation of micelles was retarded.

• Journal of Astronomy and Space Sciences
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• v.39 no.4
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• pp.169-180
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• 2022

We investigated the chemical composition of the planetary host halo star HD47536 via high-resolution spectral observations recorded using a 1.5 meter Cerro Tololo Inter-American Observatory (CTIO) telescope (Chile). Furthermore, we determined the abundances of 38 chemical elements. Both light and heavy elements were overabundant compared to the iron group elements. The abundance pattern of HD47536 was similar to that of halo-type stars, with an enrichment of heavy elements. We analyzed the relationships between the relative abundances of chemical elements and their second ionization potentials and condensation temperatures. We demonstrated that the interplay of charge-exchange reactions owing to the accretion of interstellar matter and the gas-dust separation mechanism can influence the initial abundances and can be used to qualitatively explain the abundance patterns in the atmosphere of HD47536.