• 한국수학교육학회지시리즈C:초등수학교육
• /
• 제7권1호
• /
• pp.31-41
• /
• 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.

• 약학회지
• /
• 제46권1호
• /
• pp.39-46
• /
• 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
• /
• 제8권1호
• /
• pp.15-21
• /
• 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.

• 한국약용작물학회지
• /
• 제20권4호
• /
• pp.259-269
• /
• 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.

• 생약학회지
• /
• 제21권3호
• /
• pp.210-216
• /
• 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.

• 대한한의학회지
• /
• 제21권1호
• /
• pp.53-61
• /
• 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.

• 대한가정학회지
• /
• 제24권1호
• /
• pp.43-51
• /
• 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.

• 약학회지
• /
• 제29권4호
• /
• pp.188-192
• /
• 1985

김등은 한국산 인삼의 부탄올분획이 마우스의 모르핀 내성 및 의존성 형성을 억제하였고 rat의 모르핀에 의한 내성 형성 및 dopamine 수용체 초과민성 형성을 억제한다고 보고 하엿다. 저자들은 Takagi가 보고한 인삼의 중추신경계를 억제시키는 protopanaxadiol (PD) 분획과 중추신경계를 흥분시키는 protopanaxatriol (PT) 분획을 사용하여 모르핀의 내성형성에 미치는 활성 분획을 추적할 목적으로 진통작용에 대한 내성 형성 억제 체온 상승 또는 강하 억제작용 체중감소 억제작용 등을 실험하였다.

• 대한수학교육학회지:수학교육학연구
• /
• 제24권3호
• /
• pp.467-480
• /
• 2014

초등 수학에서 지도하는 수학적 개념 중에는 구체적 조작 활동에만 의존할 것이 아니라 형식화된 사고 활동을 함께 요구할 필요가 있는 경우도 있는데 그 대표적인 것이 분수 개념이다. 가분수 개념을 도입하기 위해서는 그 이전에 두 자연수 관계로서의 분수 개념을 지도하여야 한다. 이 활동은 자연수를 몇씩 묶어 나눈 양으로서의 분수의 지도와 관련해서도 생략해서는 안 되는 중요한 활동이다. 대분수는 간단한 분수의 합과 차를 구하는 활동이 이루어진 후, 자연수와 분수의 합이라는 형식화된 추상적 개념으로 지도하여야 한다. 몫으로서의 분수 개념은 구체적 조작 활동에서 직접 도출될 수 없는 이차적 사고 또는 형식적 사고를 요구한다. 초등학생들의 논리적 사고 수준을 고려한다면 자연수 나눗셈의 곱셈 변환을 지도한 뒤에 곱셈의 결과로서 몫 분수를 표현하는 방법을 지도하는 것이 바람직하다.

• 한국식품영양과학회지
• /
• 제43권5호
• /
• pp.661-667
• /
• 2014

본 연구에서는 천년초 줄기 분말을 이용한 식품 개발에 활용하고자 천년초 줄기 분말을 용매별로 추출하여 항당뇨 및 항산화 활성을 시험하였다. 천년초 줄기의 ethyl acetate fraction을 $1,000{\mu}g/mL$ 처리했을 때 ${\alpha}$-amylase 억제활성이 $89.94{\pm}1.15%$로 가장 높았으며, 다른 fraction들은 $12.19{\pm}2.39{\sim}28.14{\pm}2.06%$로 낮았다. ${\alpha}$-Glucosidase 억제활성은 ethyl acetate fraction이 $29.01{\pm}0.49%$로 가장 높았으며, 75% ethanol fraction은 $23.48{\pm}9.89%$였고 water fraction이 $12.59{\pm}1.35%$로 가장 낮았다. 용매 분획별 total phenolics 함량과 total flavonoids 함량은 ethyl acetate fraction에서 각각 $196.02{\pm}5.26$ 및 $114.00{\pm}10.03{\mu}g/mg$으로 가장 높게 나타났다. Ethyl acetate fraction의 DPPH 및 ABTS radical 소거능은 농도 의존적으로 각각 $88.78{\pm}0.30%$ 및 $97.27{\pm}0.94%$로 가장 높게 나타났으며, 대조구인 BHT 및 비타민 C와 비슷하였다. FRAP 활성은 chloroform 및 ethyl acetate fraction에서 각각 $1.119{\pm}0.018$ 및 $1.057{\pm}0.014abs(593nm)$로 다른 fraction보다 높게 나타났다. 전체적으로 천년초 줄기의 ethyl acetate fraction의 항당뇨 및 항산화 효과가 가장 높게 나타났으며, 상업적으로 사용되는 BHT 및 비타민 C와 비슷한 항산화 효과를 나타내는 천연소재를 발굴함으로써 천년초 줄기가 항당뇨 및 항산화 활성을 갖는 식품소재로서 활용 가능성이 높은 것으로 판단되었다.