• Preventive Nutrition and Food Science
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• v.10 no.2
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• pp.118-121
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• 2005

Methanol extracts were prepared from loquat leaves (2 kg) and successively fractionated with hexane, chloroform, ethyl acetate, butanol, and water solvents. The ethyl acetate fraction exhibited the highest antioxidative and, antimicrobial activities. Therefore, the ethyl acetate fraction was purified and a chemical structure was identified by $^1H$ and $^{13}C-NMR$ spectra, FT-IR and EI/MS spectroscopies. The isolated antioxidative and antimicrobial substance was identified as epicatechin.

• Journal of Elementary Mathematics Education in Korea
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• v.21 no.4
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• pp.547-574
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• 2017

The purpose of analysis of foreign curriculums and textbooks is to aimed to get the implications for the revision of curriculum, publishment of textbooks and teaching mathematics. In this study, Common Core State Standards and its textbooks was analyzed. The U. S. doesn't have the national mathematics curriculum. So, it can be happen some problems: students' lower mathematical achievement, assessment policy, decision of teaching contents, etc. In 2010, Common Core State Standards was developed by states. Furthermore, The California Department of Education reshaped standards: CA-CCSSM. This study analyzed the contents of fraction in CA-CCSSM and its textbooks. Fraction has many concepts and methods and models in teaching process. This study analyzed the equal parts, introducing fraction concept, the types of fraction, equivalent fractions, comparison of fractions. The conclusions are as follows; The equal parts are the important concept of fraction and introduced in geometry area before teaching of fraction. CA-CCSSM aims to understand a fraction as a number on the number line and represent fractions on a number line diagram. There are some similarity and difference in mixed number, fractions as a division and ratio, equivalent fractions and comparison of fractions between Korean curriculum and textbooks and CA-CCSSM.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.9
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• pp.1197-1204
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• 2012

As an effort to develop functional food ingredients and to discover the biological activity, the total phenolic content, total flavonoid content, DPPH and ABTS radical scavenging activity, SOD-like activity, ferric reducing antioxidant power (FRAP), and $Fe^{2+}$ chelating of Aster scaber were measured using a 70% ethanol extract and various solvent fractions. As a result, the total phenolic concent was highest in an ethyl acetate fraction of 141.9 mg GAE eq/g and the total flavonoid content was 105.6 mg QUE eq/g. The DPPH radical scavenging activity was highest in an ethyl acetate fraction of 97.1% at a concentration of 1,000 ${\mu}g/mL$ (p<0.05). The ABTS radical scavenging activity showed a 86.9% ethyl acetate fraction and a 57.9% butanol fraction at a concentration of 125 ${\mu}g/mL$, and higher than that of positive control (${\alpha}$-tocopherol and BHT) (p<0.05). The SOD-like activity showed 42.8% in an ethyl acetate at a concentration of 1,000 ${\mu}g/mL$. The ethyl acetate fraction showed the highest value of FRAP at 1051.9 ${\mu}M$ and a concentration of 1,000 ${\mu}g/mL$ (p<0.05). The $Fe^{2+}$chelating was highest in the 70.1% chloroform fraction at a concentration of 500 ${\mu}g/mL$ (p<0.05). There is the highest correlation between DPPH radical scavenging activity and FRAP (r=0.981) as compared to other antioxidant assays (p<0.01). With these results, we confirmed that the ethyl acetate fraction of Aster scaber has great antioxidant potential. So it can be expected to be developed into a specific functional food ingredient.

• Korean Journal of Animal Reproduction
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• v.27 no.4
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• pp.339-347
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• 2003

The purpose of this study was to investigate the development of bovine nuclear transfer (NT) embryos cultured in serum-free conditions. Bovine NT embryos cultured in various culture conditions were compared blastocyst development, total cell number and apoptosis using TUNEL assay. In experiment 1, blastocyst rates of NT embryos were significantly higher (P<0.01) in FBS (22.0％) and BSA (26.6％) groups than in PVA (6.3％) group. Total cell number was significantly higher in FBS (78.4$\pm$19.4) and BSA (90.9$\pm$29.1) groups than in PVA group (46.0$\pm$0.0). Apoptotic cell number was significantly fewer in FBS (3.1$\pm$1.4) and BSA (1.7$\pm$1.4) groups than in PVA group (7.0$\pm$20.0) However, all of results were not different between the FBS and BSA group. In experiment 2, blastocyst rates of NT embryos were significantly higher (P<0.05) in fatty acid free-BSA (FAF-BSA) group (26.8％) than in fraction V-BSA group (11.2％). Total cell number were somewhat higher in FAF-BSA group (89.8$\pm$30.7) than in fraction V-BSA group (88.1$\pm$19.3). Apoptotic cell number were somewhat fewer in FAF-BSA (1.7$\pm$1.5) group than in fraction V-BSA group (4.2$\pm$2.9). These findings suggest that serum free condition were effective for the in vitro development of bovine NT embryos. Therefore, we concluded that fatty acid free-BSA has beneficial effect in development bovine NT embryos and can be use as a serum substitute.

• School Mathematics
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• v.14 no.2
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• pp.191-212
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• 2012

In the field of arithmetic in mathematics education, there has been lack of fine-grained investigations addressing the relationship between students' construction of division knowledge with fractional quantities and their whole number division knowledge. This study, through the analysis of part of collected data from a year-long teaching experiment, presents a possible constructive itinerary as to how a student could modify her unit-segmenting scheme to deal with various fraction measurement division situations: 1) unit-segmenting scheme with a remainder, 2) fractional unit-segmenting scheme. Thus, this study provides a clue for curing a fragmentary approach to teaching whole number division and fraction division and preventing students' fragmentary understanding of the same arithmetical operation in different number systems.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.3
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• pp.303-309
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• 2016

The human skins had a lot of changes as aging. The synthesis of collagens and elastic fibers were reduced and the expression of matrix metalloproteinase (MMPs) was increased in the dermis. These changes have been known to be responsible for skin wrinkle formation. In this study, we tried to develop pre-indicator of inner skin aging, and investigated the effect of the cream product containing Gynostemma pentaphyllum gypenoside fraction (Gynostemma pentaphyllum gypenoside cream). 21 ~ 34 years old 52 Korean female volunteers without crow's feet were chosen for this clinical study. The starting point of inner skin aging was confirmed through dermal density measurement, even though outside skin wrinkles were not observed. In addition, 4 and 8 weeks treatment of G. pentaphyllum gypenoside cream significantly increased age-related reduction of dermal density. These results suggest that the evaluation of dermal density can be used as pre-indicator of skin aging. Furthermore, G. pentaphyllum gypenoside fraction is a potential anti-wrinkle agent for prevention and treatment of skin aging.

• Journal of the Korean Applied Science and Technology
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• v.37 no.1
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• pp.145-152
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• 2020

In this study, the antimicrobial activity was tested by Ethanol extract(ET), Ethyl acetate fraction(EA) and Butanol fraction(BT) of Rhus javanica L fruit as natural preservatives. The antimicrobial activity were tested by Paper disc method and minimum inhibitory concentration (MIC) for microorganisms (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Candida Albicans). As a result of the antimicrobial activities of P. aeruginosa fruit extracts have shown the clear zone that S. aureus, S. epidermidis, E. coli, and P. aeruginosa. In BT, additional clear zones were observed for the Candida. The MIC results showed that EA samples showed the lowest concentrations for S. aureus S. epidermidis, E. coli, and P. aeruginosa. Accordingly, it can be concluded that these Rhus javanica L fruit extracts have the potential for antimicrobial materials for the cosmetic industry.

• Journal of Soil and Groundwater Environment
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• v.19 no.5
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• pp.1-8
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• 2014

The metals contamination of farmland soil nearby abandoned metal mine was serious problem in Korea. Stabilization of contaminated soil was reported using various stabilizers. Application of limestone and steel refining slag was reported as effective stabilizers in the stabilization of metals. The batch studies confirmed that the mixture of limestone and steel refining slag was suitable for stabilization of metals in contaminated soil. The limestone and steel refining slag mixture (2 : 1 and 3 : 2) were used in column studies and it was confirmed that the stabilizers effectively stabilized heavy metals in contaminated soil. The pH of the soil was increased with the addition of stabilizers. Total leached concentration of metals from the column study was reduced 44, 17, and 93% in comparison to the control at arsenic, cadmium and copper, respectively. The sequential extraction studies showed that the exchangeable fraction was changed into carbonate bound fraction (Cd and Cu) and Fe-Mn oxide bound fraction (As). Based on the results we confirmed that 2:1 ratio of limestone and steel refining slag effectively stabilizes the heavy metals. The mixed treatment of lime stone with steel refining slag would be an effective and feasible method for controlling metals leaching in contaminated soil.

• Fisheries and Aquatic Sciences
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• v.14 no.3
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• pp.168-173
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• 2011

The purpose of this study was to obtain a fraction with high antioxidative activity from second rockfish gelatin hydrolysates (SRSGHs), which were hydrolyzed with Alcalase and Flavourzyme through ultrafiltration membranes with serial digestions for 1 and 2 h, respectively, and to investigate the feasibility of this fraction as a potential functional food ingredient. Among various fractions that were ultrafiltered from the SRSGH with four types of membrane (1, 5, 10, and 30 kDa), the SRSGH-III fraction, which permeated the 10 kDa membrane but not the 5 kDa membrane, showed the highest antioxidant activity (protection factor=5.13) and angiotensin-I-converting enzyme-inhibiting activity ($IC_{50}$=0.82 mg/mL). These results suggest that the SRSGH-III fraction from the SRSGH can be used as a functional food ingredient. However, further studies examining its antioxidant activity in vivo as well as the different antioxidant mechanisms are needed.

• The Mathematical Education
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• v.58 no.1
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• pp.1-20
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• 2019

As the importance of algebraic thinking in elementary school has been emphasized, the links between fraction knowledge and algebraic thinking have been highlighted. In this study, we analyzed the solution methods and characteristics of thinking by fifth graders who have not yet learned fraction division when they solved 'reverse fraction problems' (Pearn & Stephens, 2018). In doing so, the contexts of problems were extended from the prior study to include the following cases: (a) the partial quantity with a natural number is discrete or continuous; (b) the partial quantity is a natural number or a fraction; (c) the equivalent fraction of partial quantity is a proper fraction or an improper fraction; and (d) the diagram is presented or not. The analytic framework was elaborated to look closely at students' solution methods according to the different contexts of problems. The most prevalent method students used was a multiplicative method by which students divided the partial quantity by the numerator of the given fraction and then multiplied it by the denominator. Some students were able to use a multiplicative method regardless of the given problem contexts. The results of this study showed that students were able to understand equivalence, transform using equivalence, and use generalizable methods. This study is expected to highlight the close connection between fraction and algebraic thinking, and to suggest implications for developing algebraic thinking when to deal with fraction operations.