• Title/Summary/Keyword: Polyethyleneimine Plate

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Electrical and Mechanical Properties of Cu/Carbon Nano-Particle Hybrids Composites by Cathodic Electrophoresis (음극 전기영동법에 의해 제조된 구리/탄소 나노입자 하이브리드 복합재료의 전기적/기계적 특성 평가)

  • Lee, Wonoh;Lee, Sang-Bok;Choi, Oyoung;Yi, Jin-Woo;Byun, Joon-Hyung
    • Korean Journal of Metals and Materials
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    • v.48 no.12
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    • pp.1130-1135
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    • 2010
  • Cu/carbon nano-particle hybrids were fabricated through the cathodic electrophoretic deposition (EPD) process. CNT and CNF nano-particles were modified to give positive charges by polyethyleneimine (PEI) treatment before depositing them on the substrate. Since a Cu plate was used as an anode in the EPD process, Cu particles were also deposited along with the carbon nano-particles. Experimental observation showed the nano-hybrids constructed a novel formicary-like nano-structure which is strong and highly conductive. Utilizing the hybrids, carbon fiber composites were manufactured, and their electrical conductivity and interlaminar shear strength were measured. In addition, the deposition morphology and failure surface were examined by SEM observations. Results demonstrated that the electrical conductivities in the through-the-thickness direction and the interlaminar shear strength significantly increased by 350~2100% and 14%, respectively.

Ribonucleotide Reductase Activity of Schizosaccbarornyces pombe Is Inhibited by Escherichia coli RecA Antibody (Schizosaccbarornyces pombe에서 Escherichia coli RecA 항체에 의한 Ribonucleotide Reductase 효소활성 저해)

  • Lee, Jung-Sup;Chun, Min-Suck;Kim, Ok-Bong;Park, Jong-Kun;Kim, Si-Wouk;Park, Yeal;Yang, Young-Ki;Hong, Seung-Hwan;Park, Sang-Dai
    • The Korean Journal of Zoology
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    • v.38 no.4
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    • pp.565-569
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    • 1995
  • We have previoosly demonstrated that the RecA-like protein of Schizosaccharomyces pombe (S. pombe) is immunologically related to Escherichia coil (E. coil) RecA protein and that the cellular level of the protein is significantly increased by inhibitors of nucleotide pool-forming enzymes such as hydroxyurea (HU) and methotrexate (MTX) (lee and Park, 1994; lee et al., 1994). In this study, we report that the ribonudeotide redudase activity of S. pombe is inhibited by E. coil RecA antibody, as determined by thin layer chromatography using [5-$^3$H]CDP as a substrate. The relative activity of ribonucleotide reductase was dramatically inhibited by 100 mM of flu (26.4% reduction) in in vitro assay, compared to that of non-treated control. The ribonucleotide reductase activity was also inhibited by immunoprecipitation with E. coil RecA antibody (43.3% reduction). These results indicate that the strudure of S. pombe ribonucleotide reductase is in part similar to that of E. coil RecA protein.

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