• Journal of the Korean Chemical Society
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• v.52 no.3
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• pp.303-314
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• 2008

The purpose of this study was to understand the experiment for measuring chemical reaction rate by precipitate formation and to develop experiments applying small-scale chemistry. For this study, the experimental method for measuring the effect of concentration and temperature on chemical reaction rates presented in the 10 high school science textbooks were classified by their experimental methods of confirming production. Subsequently, problems observed in carrying out the experiments for measuring chemical reaction rates by precipitate formation frequently presented in the 10 high school science textbooks were analyzed. Experiments applying small-scale chemistry were developed measuring chemical reaction rate by precipitate formation. According to the result of this study, there were some problems in the experimental method of precipitate formation for measuring chemical reaction rates presented in the high school science textbooks. Those problems in the science textbook experiments were insufficient specification of mixing methods of reaction solutions, obscurity of knowing when the character letter X disappeared, time delay in collecting the experimental data, formation of hazardous sulfur dioxide, uneasiness of fixing water bath container, controlling the reaction temperature, and low reproducibility. Those problems were solved by developing experiments applying smallscale chemistry. Presenting the procedure of mixing reaction solutions on the A4 reaction paper sheet made the experimental procedure clearly, using well plates and stem pipette shortened the reaction time and made it possible to continuously collect the experimental data. Furthermore, the quantity of hazardous sulfur dioxide was reduced 1/7 times and the time when the character letter X disappeared could be observed clearly. Since experiments for measuring the effect of concentration and temperature on chemical reaction rates could be performed in 30 minutes, the developing experiments applying SSC would help students understand the scientific concepts on the effect of concentration and temperature on chemical reaction rates with enough time for experimental data analysis and discussion.

• The Journal of the Korea Contents Association
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• v.15 no.4
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• pp.45-55
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• 2015

The Korean wave contents such as Korean TV dramas and K-pop are sweeping over foreign countries. This Korean wave has improved positive national brand image and also brought up interest across Korean culture. Due to expansion of Korean wave, some Korean education contents started to be made by using Korean wave contents. These kinds of Korean educational online contents induce interest in studying Korean by using Korean wave contents. Furthermore, people can indirectly experience Korean culture. so we need to come up with more effective application plan. However, contents which has produced currently still have insufficient part. Based on that, current state of Korean education online contents by using Korean wave contents will analyze into especially a series of 'Pit-A-Pat Korean' from Nuri-Sejong school need to be proposed a review of the limitations and improvement conclusion in this paper. The K-drama produced by effectively utilizing the planning and the Korean educational content. This will reveal to the culture and traditions of Korea, as well as a simple information transfer. So we expect to be a valuable activity that is responsible for a stem to improve the country's image as one item K-culture itself.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.5
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• pp.711-720
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• 2009

Leaf fibers have many good properties; they are strong, long, cheap, abundant and bio-degradable. Since they, however, contain a great quantity of non-cellulose components, they have been used for the materials of mats, ropes, bags and nets rather than those of clothing. In this study, we investigated the characteristics of leaf fibers in order to promote the use of leaf fibers for the materials of clothing as well as develop the high value-added textile fibers. Leaf fiber plants including New Zealand Flax, Henequen and Banana plant, which have various nature and shape, were used. New Zealand Flax and Henequen leaves were cut from lower part of plants. Banana leaves and pseudo-stems were peeled and cut from the stem of Banana plants. First, the thin outer skins like film of leaves, veins and stems were removed before retting. The chemical retting had been processed for 1hour, at 100 in 0.4% $H_2SO_4$ aqueous solution(liquid ratio 50:1). Then, the retted leaf fibers had been soaked for 1hour, at room temperature in 0.5% NaClO solution(v/v) to remove the miscellaneous materials. We investigated the physical characteristics of three leaf fibers including the transversal and longitudinal morphology, the contents(%) of pectin, lignin and hemicellulose, the length and diameter of fibers, the tensile strength of the fiber bundles, and the fiber crystallinity and the moisture regain(%). The lengths of fiber from three leaf fibers were similar to their leaf lengths. The fiber bundles were composed of the cellulose paralleled to the fiber axis and the non-cellulose intersecting at right angle with the fiber axis. The diameters of New Zealand Flax, Henequen and Banana fibers were $25.13{\mu}m$, $18.16{\mu}m$ and $14.01{\mu}m$, respectively and their tensile strengths were 19.40 Mpa, 32.16 Mpa and 8.45 Mpa, respective. The non-cellulose contents of three leaf fibers were relatively as high as 40%. If the non-cellulose contents of leaf fibers might be controlled, leaf fibers could be used for the materials of textile fiber, non-wovens and Korean traditional paper, Hanjee.

• Journal of Life Science
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• v.31 no.3
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• pp.266-279
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• 2021

The present study examined the cytotoxic effects of a Smilax china L. extract (SCLE) in human cancer (A-549, MCF-7, MDA-MB-231, U87-MG, AGS, MKN-74, and SNU-601) and normal MRC-5 fibroblasts, as well as in mesenchymal stem cells derived from dental tissue (DSC). The 50% inhibitory concentration (IC50) values for SCLE were significantly (p<0.05) lower in the cancer cell lines (A-549, MCF-7, MDA-MB-231, U87-MG, AGS, MKN-74 and SNU-601) than in the MRC-5 and DSC cells. Cell growth was significantly (p<0.05) more inhibited in the cancer cell lines treated with 200 ㎍/ml SCLE than in the normal MRC-5 and DSC, and anoikis-like floating cell morphology was observed in the SCLE-treated cancer cells. The cells detached by SCLE treatment were retrieved daily and assayed for viability and telomerase activity. Cells retrieved at 4 days showed significantly decreased viability and telomerase activity (p<0.05), as well as apoptosis-like abnormal morphology, when compared to cells retrieved in the previous 3 days. The ratio of apoptosis and cells in the G1 phase was significantly (p<0.05) increased in the A-549, AGS, and MCF-7 cancer cells treated with SCLE for 4 days compared to untreated controls. However, after SCLE treatment, cell adhesion was not increased by application of an inhibitor of the associated protein kinase (ROCK) that mainly contributes to the increase in cell attachment. This suggests that the cellular detachment by SCLE is probably controlled by a Rho-independent mechanism(s). These observations indicate that SCLE readily induces anoikis in cancer cells and could serve as a potent agent for cancer chemotherapy.

• Journal of Practical Agriculture & Fisheries Research
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• v.24 no.4
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• pp.53-61
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• 2022

Growing agricultural products in greenhouses controlled by creating suitable climatic conditions and root zone of crop has been an important research and application subject. Appropriate environmental conditions in greenhouse are necessary for optimum plant growth improved crop yields. This study aimed to establish web-based remote monitoring system which monitors crops growth environment and status of crop on a real-time basis by applying to greenhouses IT technology connecting greenhouse equipment such as temperature sensors, soil sensors, crop sensors and camera. The measuring items were air temperature, relative humidity, solar radiation, CO₂ concentration, EC and pH of nutrient solution, medium temperature, EC of medium, water content of medium, leaf temperature, sap flow, stem diameter, fruit diameter, etc. The developed greenhouse monitoring system was composed of the network system, the data collecting device with sensors, and cameras. Remote monitoring system was implemented in a server/client environment. Information on greenhouse environment and crops is stored in a database. Items on growth and environment is extracted from stored information, could be compared and analyzed. So, A integrated monitoring system for smart greenhouse would be use in application practice and understanding the environment and crop growth for smart greenhouse management. sap flow, stem diameter and pant-water relations

• The Korean Journal of Ecology
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• v.4 no.3_4
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• pp.114-123
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• 1981

Diurnal acid fluctuations, stomatal resistance, and morphology and anatomy were investigated in leaves and stems P. oleracea L. growing under the natural environmental condition. A CAM-like pattern of acid fluctuation was exhibited not in leaves of the young purslane but in its stems. Defoliated stems showed a decreased in diurnal changes of total acidity as compared with normal stems. Excised stems stored in continuous darkness exhibited diurnal acid rhythms, and they showed light deacidifications for three days. Kranz-type arrangement was observed in leaves, but not in stems. Micrography of cross sections of stems showed cells with relatively large vaculoles and a few chloroplasts. The number of stomata was 3,275cm-2 in leaves, while the stomata could not be observed in stems. Stomatal resistance was high at night and low in daytime in leaves of the young purslane, and the range of its value was 5~40 sec.$\textrm{cm}^{-1}$. But stomatal resistance in leaves of the water-stressed plant was comparratively high in day time, and its value was 30 sec.$\textrm{cm}^{-1}$. The result of these studies showed the possibility that the stem of P.oleracea L. possesses CAM under certain stressed conditions.

• Journal of The Korean Association For Science Education
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• v.32 no.2
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• pp.320-330
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• 2012

Understanding the relation between basic science and applied science is important for students in understanding the importance of learning science, the relationship between scientific knowledge and human life, and for enhancing their science motivation. In this study, we evaluated the statistical validity of this hypothetical model and explored the effect of gender and students' preferred courses (e.g., humanities, science, and art) on four dependent variables. We also evaluated the differences of students' understanding across scientific domains and students' understanding concerning basic and applied scientific knowledge. Three hundred and twenty five 10th grade students participated in this survey research. Statistically, we employed bivariate correlation, partial correlation, path analysis, two-way ANOVA, and repeated measures ANOVA. Our findings illustrated that our hypothetical model was statistically valid. In addition, the significant interaction effects of gender and students' preferred courses on each dependent variable were shown. Students have different levels of understanding of the convergence of basic and applied science, the relation between scientific knowledge and human life, and the importance of learning science across scientific domains (e.g., physics, chemistry, earth science and biology).

• Journal of Elementary Mathematics Education in Korea
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• v.17 no.2
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• pp.185-205
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• 2013

In this study, to begin with, it was discussed to gather vocabularies which are expected to be vocabularies related to four fundamental rules of arithmetic and classify them according to kinds and groups, to demarcate vocabularies related to four fundamental rules of arithmetic for using in elementary school mathematics which are associated with addition, subtraction, multiplication, and division directly. Next, the basic vocabularies related to four fundamental rules of arithmetic were discussed. At this time, regarding vocabularies related addition, subtraction, multiplication, and division as coming from the verb add, subtract, multiply, divide respectively, vocabularies that contains the stem of each verb were considered as the basic vocabularies related to four fundamental rules of arithmetics. Following it, vocabularies which assist the operation and indicate the result of the operation were included, then, vocabularies related to four fundamental rules of arithmetic for using in elementary school mathematics were demarcated and presented according to the following criteria. First, a newly coined verb or derivative using the noun form of a certain verb as a root should not be used. Second, such vocabularies of which examples do not exist or rarely exist in textbooks/workbooks should not be used, even though they are registered in mathematics glossary book published by ministry of education or Korean dictionary published by the national institute of Korean language. Third, vocabularies which are not replaceable and vocabularies which have some didactical reasons for using them should be used.

• Journal of the Korean Society of Earth Science Education
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• v.15 no.2
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• pp.285-298
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• 2022

This study is to investigate the effects and characteristics of science and engineering integrated lessons on elementary students' creative engineering problem solving propensity (CEPSP). The science and engineering integrated lessons used in this study was a 10 lesson-hours STEM program, co-developed by University of Minnesota and Purdue University. The program was implemented in the 6th grade science class of H Elementary School located in P Metropolitan city. The main data of this study are the pre-post CEPSP result and interview with 5 students collected before and after the research. The CEPSP result was analyzed by a paired-sample t-test and hierarchical cluster analysis. As a result of the t-test, it was found that overall, the program has a positive effect on the students' CEPSP score. As a result of cluster analysis, it was confirmed that studnets' CEPSP could be classified into two groups (lower and higher score cluster). Five students whose, CEPSP score has significantly improved after the lessons were interviewed to find out what the characteristics of the program that contribute the significant change are. As a result of conducting centroid analysis of the interview transcription and the hybrid analysis method, it was found that the meaningful experiences that the five students commonly shared were 'problem solving through collaboration' and 'through repeated experiments (redesign)', problem solving' and 'utilization of scientific knowledge'. As minor reactions, 'choice of the best experimental method' and 'difference between science and engineering' appeared.

• Journal of Life Science
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• v.34 no.6
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• pp.365-376
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• 2024

The present study assessed the cytotoxic effects on cell growth and senescence in human cancer (A-549, AGS, HCT-116, MDA-MB-231, and U 87-MG) and normal (MRC-5 and mesenchymal stem cells) cell lines treated with efavirenz (EFA), an inhibitor of non-nucleoside reverse transcriptase (RTase). Following EFA treatment, the half-maximal inhibitory concentration (IC₅₀) values were approximately 15 µM, and the IC₅₀ value was significantly (p<0.05) lower in the cancer cell lines, compared to normal cell lines. After determining the IC₅₀ values against EFA, each cell line was treated with 15 µM EFA for up to one week. Significant (p<0.05) decreases in endogenous RTase and telomerase activity were observed in the cancer cell lines. RTase and telomerase activity were absent or detected at very low levels in both EFA-untreated and treated MRC-5 and MSC normal cells. The cell doubling time (CDT) was also significantly (p<0.05) prolonged by the decreased cell growth rate in the EFA-treated cancer cell lines compared to the untreated cell lines. Furthermore, EFA-treated cancer cells displayed a high number of cells with a high intensity of senescence-associated ß-galactosidase activity (SA-ß-gal activity), compared to the untreated cells. The present study showed that inhibition of RTase activity induces cellular senescence and arrests cell growth in human cancer cell lines; however, normal cell lines showed greater tolerance against EFA. RTase treatment could offer optional chemotherapy for cancer treatment in human cancer cell lines with high RTase activity.