• Education of Primary School Mathematics
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• v.7 no.1
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• pp.31-41
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• 2003

Representation has been main topic in teaching and learning mathematics for a long time. Moreover, teachers' deficiency of representation about fraction results in teaching algorithms without conceptual understanding. So, this paper was conducted to investigate and analysize the elementary preservice mathematics teachers' representation about fraction. 38 elementary preservice mathematics teachers participated in this study. This study results showed that, the only model of a fraction that was familiar to the preservice teachers was the part of whole one. And research showed that, they solved the problems about fraction well using algorithms but seldom express the sentence which illustrates the meaning of the operation by a fraction. Specially, the division aspect of a fraction was not familiar nor readily accepted. It menas that preservice teachers are used to using algorithms without a conceptual understanding of the meaning of the operation by a fraction. This results give us some implications. Most of all, teaching programs in preservice mathematics teachers education have to devise to form a network among the concepts in relation to fraction. And we must emphasize how to teach and what to teach in preservice mathematics teachers education course. Finally, we have to invent the various materials which can be used to educate both preservice teachers and elementary school students. If we want to improve the mathematical ability of students, we will concentrate preservice teachers education.

• YAKHAK HOEJI
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• v.46 no.1
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• pp.39-46
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• 2002

The water fraction exhibiting anticancer activity was prepared from 70% methanol extract of Artemisis argyi by stepwise solvent partioning. This water fraction(5 $\mu$g/ml concentration) showed a considerable cytotoxicity against leukemic L1210 cells with a maximal value of 92% for 3 days culture. Contrastingly to such substantial anticancer activities the identical fraction showed far low toxicity against normal lymphocytes than chloroform fraction of Artemisia argyi mitomycine and 5-fluorouracil at every concentration ranging 0.01$\mu$g/ml~10.00$\mu$g/ml. The cytotoxicity displayed against L1210 cells by the water fraction of Artemisia was found to be proportinal to the decrease of viability of L1210 cells. On the other hand, $O_2$ion generation in L1210 cells appeared to be elevated in accordance to cytotoxicity by the water fraction with concurrent increases of superoxide dismuatse (SOD) and glutathione peroxidase (GPx) which are responsible for the conversion of $O_2$ ion and $H_2O$$_2$ respectively These findings taken together indicate that the death of L1210 cells by the water fraction of Auemisia atgyi, may be induced at least in part by the detrimental action of reactive oxygen species (ROS) including $O_2$- in spite of substantial extorts of SOD and GPx to overcome the attack of ROS.

• Journal of Ginseng Research
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• v.8 no.1
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• pp.15-21
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• 1984

It has been known that ethyl acetate fraction and petroleum ether fraction prepared from ginseng are inhibitory to the L5178Y and sarcoma 180 cell at the concentrations o! 0.Imgfml or 0.2mg/ml. The shiny was carried out to examine effects of the two fractions on the activities of RNA polymerase, succinate dehydrogenase (SDH) and malate dehydrogenase (MDH) present in normal rabbit liver. The ethyl acetate fraction did not show any inhibitory effect on the RNA polymerase and SDH activity at the concentrations of 0.Imgfml and 0.2mglml, but inhibited malate dehydrogenase activity by 12.3% and 15.5%, at the same concentrations, respectively. The fraction also inhibited all the three enzymes at higher concentrations tested, but stimulated the succinate dehydrogenase activity at 0.024mg/ml to increase the enzyme activity by 14.6%. The petroleum ether fraction activated the SDH activity by 12.9% and 20.8%, at the concentration of 0.1mg/ml and 0.2mg/ml respectively. But the fraction did not affect the MDH activity at the same concentration. The fraction, however, inhibited the MDH activity and activated the SDH activity by 13.5% and 18.2%, at the concentration of 0.8mg/ml respectively.

• Korean Journal of Medicinal Crop Science
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• v.20 no.4
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• pp.259-269
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• 2012

This study was performed to determined the antioxidant activities, anticancer and immuno-activities of anthocyanin fraction from Rubus coreanus Miquel fruits (Bokbunja). Anthocyanin fraction extracted from Bokbunja revealed the presence of three anthocyanin components, which were tentatively identified as cyanidin 3-O-sambubioside, cyanidin 3-O-xylosylrutinoside and cyanidin 3-O-rutinoside using RP-HPLC/DAD/MS. The anthocyanin fraction from Bokbunja always showed reducing power and high scavenging activities against DPPH, hydroxy radical (OH) and superoxide anion radical ($O_2{^-}$) similar to general synthetic antioxidant and polyphenol compounds from plant origin. Anthocyanin fraction from Bokbunja showed high inhibition on proliferation of LNCaP and A549 cells and did not inhibit the proliferation of other cancer cells. Immuno-activities of Anthocyanin fraction from Bokbunja were investigated, it showed high promotion of human B and T cells growth about 50% and secretion of IL-6 and TNF-${\alpha}$ by treatment after 6 days. Over all, the result of the study suggest that anthocyanin fraction from Bokbunja displays antioxidant activity comparable to that general synthetic antioxidant, also, anthocyanin fraction from Bokbunja are expected to be good candidate for development into source of anticaner and immuno-activator agent in food industry.

• Korean Journal of Pharmacognosy
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• v.21 no.3
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• pp.210-216
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• 1990

Effects of the protein fraction of Panax ginseng on chicken embryonic skeletal muscle cells cultured with a decfiient medium were studied. The protein fraction was further fractionated into four groups according to the molecular weight; larger than 10,000 dalton(fraction A), between 5,000 and 10,000 dalton(fraction B), between 1,000 and 5,000 dalton(fraction C), between 500 and 1,000 dalton(fraction D). According to the microscopic observation, all four protein fractions at the concentration of $10{\sim}100{\;}{\mu}g/ml$ showed the tendency to stimulate the growth and differentiation of the muscle cells. The activity of acetylcholinesterase in muscle cells was significantly elevated by the protein fraction A at the concentration of $100{\mu}{\;}g/ml$. Protein fractions B,C and D significantly enhanced the synthesis of RNA in the muscle cells. The synthesis of DNA in muscle cells was significantly enhanced by protein fractions A,B and C.

• The Journal of Korean Medicine
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• v.21 no.1
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• pp.53-61
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• 2000

Objectives: This study was camed out to examine the effect of five fractions of aqueous extract from Artemisia capillaris THUNB(ACT), on TGF, 1-induced apoptosis, cell viability, cell cycle progression and mRNA expression of apoptosis-related genes in human hepatocyte cell line HepG2. Methods: This study employed Tryphan blue exclusion assay, DNA fragmentation assay, Cpp32 protease activity assay and Quantitative RT-PCR analysis. Results: In the Tryphan blue exclusion assay, the butanol fraction of ACT with $TGF{\beta}$, l showed magnificent (Nice word, ut is it appropriate in a medical abstract\ulcorner) viability and the H2O fraction of ACT with $TGF{\beta}$, l also showed higher viability than only $TGF{\beta}$, l-treated group. DNA fragmentation assay showed that the butanol fraction and the H2O fraction carried inhibitory effects on apoptosis induction, with the butanol fraction displaying greater effects. The Cpp32 protease activity assay showed that the butanol fraction decreased Cpp32 protease activity. The H2O fraction of ACT had no significant effect on the Cpp32 protease activity. Quantitative RT-PCR showed that the butanol fraction suppressed Bax, p 15/INK4B, p21/Waf1, PAI-1 and increased Bcl-2 gene. Conclusions: The data shows that butanol fraction of ACT increases the hepatocyte viability and has the hepatocellular protective effect by the suppression of $TGF{\beta}$, l induced-apoptosis through gene regulation.

• Journal of the Korean Home Economics Association
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• v.24 no.1
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• pp.43-51
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• 1986

In order to study antioxidative acton of garlic, alliin, scordinin, garlic oil, ethanol fraction and non-kaolin fraction which have been discovered from garlic until now were extracted and isolated, and each fraction was utilized as the experimental materials. Antioxidative action of each fraction was compared through the in vitro and in vivo experiments. Electron donatingability on $\alpha$, $\alpha$-diphenyl-$\beta$picrylhydra-$\chi$yl, the inhibitory effect of lipoperoxide formation by TBA and peroxide value were measured and analyzed. RESULTS : 1. When observed antioxidative ability by EDA value, ethanol fraction of garlic components showed the strongest reaction as 15.25. 2. In vitro experiment with TBA value, garlic oil, alliin and ethanol fracton showed distinctive effect on inhibitory effect of lipoperoxide formation. 3. Comparing with the inhibitory effect of lipoperoxide formation with TBA value in vivo, the ethanol fraction was the most effective in the blood or liver by intraperitoneal administration, whereas the ethanol fraction in the blood and non-kaolin fraction in the liver was most effective each other by orally administration. 4. In vitro experiment with peroxide value, garlic oil was distinctive effect on the inhivitory effect of lipoperoxide formation, which was a similar to the trend of TBA value in vitro. 5. Examining the induction time for the first period of lipoperoxide formation in vitro, garlix oil, ethanol fraction and alliin were effective, which was a similar to the trend of TBA value and peroxide value in vitro.

• YAKHAK HOEJI
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• v.29 no.4
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• pp.188-192
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• 1985

Protopanaxadiol (PD) fraction and protopanaxatriol (PT) fraction were separated from thebutanol fraction of panax ginseng roots. Each group of mice was injected with morphine hydrochloride (40 mg/kg s.c.) three times at 8 hr intervals for a period of 6 days. PD fraction and PT fraction were injected (25, 100 mg/kg i.p.) to mice 1 hr prior to the third morphine injection daily. Inhibition of morphine tolerance was evidenced by the increase in analgesic response to morphine hydrochloride (10mg/ kg i.p.) as estimated by the tail flick method. Inhibition of morphine tolerance by PT fraction was effective but there was no remarkable difference in inhibition of tolerance development between control group andPD fraction group.

• Journal of Educational Research in Mathematics
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• v.24 no.3
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• pp.467-480
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• 2014

Concepts related to the fraction should be taught with formative thinking activities as well as concrete operational activities. Teaching improper fraction should follow the concept of fraction as a relation of two natural numbers. This concept is also important not to be skipped before teaching the fraction such as "4 is a third of 12". Mixed number should be taught as a sum of a natural number and a proper fraction. Fraction as a quotient of a division is a hard concept to be taught since it requires very high abstractive thinking process. Learning the transformation of division into multiplication of fractions should precede that of fraction as a quotient of a division.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.5
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• pp.661-667
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• 2014

To investigate the anti-diabetic and antioxidant effects of Opuntia humifusa cladodes, O. humifusa cladodes powder was extracted with 75% ethanol and fractionated with various solvents. Among the extracts fractionated with various solvents, ${\alpha}$-amylase and ${\alpha}$-glucosidase inhibitory activities of O. humifusa cladodes were highest ($89.94{\pm}1.15%$ and $29.01{\pm}3.03%$, respectively) in the ethyl acetate fraction. Further, total phenolic and flavonoid contents of the ethyl acetate fraction were the highest ($196.02{\pm}5.26$ and $114.00{\pm}10.03{\mu}g/mg$, respectively). DPPH and ABTS radical scavenging activities increased according to the concentration of O. humifusa cladodes extract, and those of the ethyl acetate fraction were the highest. Ferric reducing antioxidant powers of chloroform and the ethyl acetate fraction were higher than those of other fractions. Overall, the ethyl acetate fraction of O. humifusa cladodes showed the highest anti-diabetic and antioxidant effects. Results indicate that O. humifusa cladodes powder has potential as a useful ingredient with anti-diabetic and antioxidant effects.