• 제목/요약/키워드: MgB2

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Analysis of Influence of Environmental Conditions on Ganoderic Acid Content: in Ganoderma lucidum Using Orthogonal Design

  • Li Na;Liu Xiao Hua;Zhou Jie;Li Yu Xiang;Zhao Ming Wen
    • Journal of Microbiology and Biotechnology
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    • v.16 no.12
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    • pp.1940-1946
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    • 2006
  • The influence of environmental conditions on the ganoderic acid (GA) content in the fungus Ganoderma lucidum was investigated using a one-factor-at-a-time design and orthogonal design. Among the various medium components examined, sucrose, soybean powder or peptone, ferrous sulfate, and pH 6.0 were the most suitable carbon source (factor A), nitrogen source (factor B), mineral source (factor C), and initial pH (factor D), respectively, for the GA content in the one-factor-at-a-time design. According to the orthogonal design, the order of effect for the four factors on the GA content was A>C>D>B. The best level of factor A was $A_2$ (sucrose) with a value of +0.34 mg/100 mg DW. The optimal treatment combination was $A_2B_1C_3D_1$ with which the GA content reached up to 2.63$\pm$0.011 mg/100 mg DW. The interactions between the mineral ion and the nitrogen source, and the mineral ion and the pH were both highly significant (P<0.01). The highest interaction effect was ($B_2{\times}D_2$) with a value of +0.19 mg/100 mg DW, which was higher than the level effect value for $B_2$ (peptone) and D$_2$ (pH 5.0). Therefore, the results proved that interactions between factors cannot be ignored. The results also indicated the importance of the interactions between the factors, which may help to understand the metabolic pathway leading to triterpene biosynthesis and the expression and regulation of the key enzymes involved.

AN EXPERIMENTAL STUDY ON THE LOW-DOSE RADIOSENSITIVITY OF TUMOR CELL LINES (수종의 암세포주의 저선량 방사선감수성에 관한 실험적 연구)

  • Kim Min-Sook;Koh Kwang-Joon
    • Journal of Korean Academy of Oral and Maxillofacial Radiology
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    • v.24 no.2
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    • pp.249-260
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    • 1994
  • The purpose of this study was to aid in the radiation therapy of head and neck cancer patients. For this study, radiation survival curves were generated for Bl6, MG-63 and YAC-l cell lines using semiautomated MTT assay and Dye Exclusion Assay. Irradiation of 2, 4, 6, 8, 10Gy were delivered at room temperature at a dose rate of 210.2cGy/min using / sup 60/Co γ-ray Irradiator ALOORAOO 8. The viable cells were determined for each radiation dose and compared to control values. The obtained results were as follows: 1. There was significantly different absorbance at 10Gy on B16 cell line in MTT assay(P<0.05). 2. There was significantly different absorbance at 4, 6, 8, 10Gy on MG-63 cell line in MTT assay(P<0.05). 3. YAC-l cell line was more sensitive than B16 or MG-63 cell line to all doses of radiation(P<0.05). 4. There was significantly different absorbance among all tumor cell lines except between B16 and MG-63 cell line at ZGy in MTT assay(P<0.05). 5. Good correlation was obtained between MTT assay and DEA(P<0.05). The efficient of correlation of B16, MG-63 and YAC-l cell line was 0.845, 0.824 and 0.906, respectively.

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Magnetic Pinning Properties and Flux Jumps in Superconducting $MgB_2$

  • Yoon, W.S.;Lee, Eui-Wan;Kim, C.J.;Kim, B.G.;Ri, H.C.
    • Progress in Superconductivity
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    • v.9 no.1
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    • pp.11-17
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    • 2007
  • Magnetization studies have been carried out on $MgB_2$ polycrystalline samples in the temperature range of 5 - 44 K and in the magnetic field up to 7 Tesla. The critical current density was calculated from hysteresis loops using the Bean's critical state model, and the highest value of $J_c$ at 20 K was $2.7{\times}10^5\;A/cm^2$ at 2 Tesla. The hysteresis loops were carefully examined to determine the temperature and magnetic field range where flux jumps appeared. The first jump occurred typically at 1 Tesla. Due to the strong pinning, we observed the presence of flux jump below H = 1 Tesla at temperature below 30 K.

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Dietary Intake and Major Dietary Sources of Vitamin $B_6$

  • Cho, Youn-Ok;Kim, Young-Nam
    • Nutritional Sciences
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    • v.4 no.1
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    • pp.20-25
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    • 2001
  • The dietary vitamin $B_6$ intake of 218 Korean young women (aged 20-26y), who had no health problems, and their sources were estimated using a modified Korean vitamin $B_6$ database. The average daily vitamin $B_6$ intake was 0.987 mg for the subjects. About 87.2% of the subjects consumed less than the Korean Recommended Dietary Allowance (RDA) of vitamin $B_6$. The average ratio of vitamin $B_6$ intake to daily protein intake was 0.014 mg/g protein, and approximately 91% of subjects consumed 〈 0.02 mg/g protein. Vitamin $B_6$ intake was significantly (p〈.01 -p〈.001) positively correlated to the intakes of all other nutrients. Between animal and vegetable protein, animal protein had a stronger positive correlation with vitamin $B_6$. Major dietary sources of vitamin $B_6$, the top 10 foods provided nearly 64% of total vitamin $B_6$, and dietary contributors of vitamin $B_6$ for Koreans are less varied than those for Americans.

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Mechanical Properties of 0.25-0.65wt% CaO added AM60B Eco-Mg Diecastings at room and Elevated Temperatures (0.25-0.65wt% CaO 첨가 AM60B Eco-Mg 다이캐스팅 부품의 상온 및 고온 기계적 특성)

  • Seo, Jung-Ho;Kim, Shae-K.
    • Journal of Korea Foundry Society
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    • v.31 no.1
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    • pp.11-17
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    • 2011
  • The effect of CaO addition to AM60B Mg alloy on tensile properties has been investigated, with focus on strength and ductility at room and elevated temperatures. The 0.25-0.65wt% CaO added AM60B Eco-Mg diecastings were prepared by high pressure die casting using Buhler 1,450-ton cold chamber machine without $SF_6$ and $SO_2$ gases. The microstructures and tensile properties of each alloy were tested. The results show that the grains of AM60B are refined and the mechanical properties increase with CaO addition at room temperature. The improvement of strength and ductility is prominent at 0.45-0.55wt% CaO addition. Also, improved mechanical properties are maintained at elevated temperature of $150^{\circ}C$. CaO addition results in $Al_2Ca$ phase formation mostly on the grain boundaries. This phase leads to the refinement of grain structures and improvement of ductility as well as strength. The suppression of ${\beta}-Mg_{17}Al_{12}$ phase as well as the decrease of fracture surface porosity and other casting defects caused by melt cleanliness also contribute to the enhancement of mechanical properties of AM60B Eco-Mg at room and elevated temperature.

Anti-Thrombogenic and Anti-Inflammatory Effects of Solvent Fractions from Leaves of Zanthoxylum Schinifolium (Sancho Namu) in Rats Fed High Fat Diet (고지방식이 흰쥐에서 산초나무 Butanol 및 Methylene Chloride 분획의 항혈전 및 항염증 작용)

  • Jang, Hyun-Seo;Rhee, Soon-Jae;Woo, Mi-Hee;Cho, Sung-Hee
    • Journal of Nutrition and Health
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    • v.40 no.7
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    • pp.606-615
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    • 2007
  • This study was performed to investigate anti-thrombogenic, anti-inflammatory effects of n-BuOH (B) and $CH_2Cl_2$ (MC) fractions extracted from Sancho (Zanthoxylum. schinifolium) leaves in rats fed high fat diets. The experimental animal groups were consisted of eight including one 5% fat (N) and one 20% fat (H) without the test materials in diets and six H groups of feeding three levels (50, 100 and 150 mg/day) of the B and the MC fractions from Z. schinifolium, respectively. Plasma activated partial thromboplastin times and thrombin times of H group were decreased compared to the N group, but they were increased by feeding the MC fraction of 50 mg and over. Polymorphonuclear leukocyte 5#-lipo-xygenase activities and leukotriene $B_4$ contents of the H group were significantly increased compared to the N group, but they were decreased in the 100 mg and 150 mg of B fraction or the 150 mg of MC fraction fed groups. Liver cytochrome $P_{450}$, $O_2^-$, $H_2O_2$ and GSSG contents were increased by the high fat diet but decreased by feeding the B fraction or the MC fraction, while GSH content and glutathione S-transferase activity lowered by high fat diet were increased by feeding the two solvent fractions. The effects of the solvent fractions were evident at the level of 100 mg/day and over. The present results confirmed that two solvent fractions from the leaves of Z, schinifolium have enhancing effects on anti-thrombosis and anti-inflammation partly by antioxidant action and partly by direct modulation of the respective processeds. In conclusion, the n-BuOH and $CH_2Cl_2$ fractions from leaves of Z, schinifolium can be utilized as the proper ingredients of functional foods for preventing chronic degenerative disease.