Online ISSN : 2186-2451
Print ISSN : 1344-3542
ISSN-L : 1344-3542
Volume 80 , Issue 6
Showing 1-19 articles out of 19 articles from the selected issue
  • Sorin KIHARA, Megumi KASUNO, Tomohiko OKUGAKI, Osamu SHIRAI, Kohji MAE ...
    2012 Volume 80 Issue 6 Pages 390-400
    Published: June 05, 2012
    Released: June 05, 2012
    Some biomimetic reactions observed with the aid of aqueous/organic, W/O, two phases or liquid membrane, LM, systems were introduced. The reactions introduced were mostly those reported by the group of present authors as follows; (1) Transformations of porphyrin iron(III) complex, Fe(P), and α-tocopherol, α-TOH, derivatives in O contacted with W. (2) The oxidation of Fe(P) in O with an oxidant in W, α-TOH in O with nitric oxide in W or hydroquinone in O with oxygen in W, and the reduction of quinone in O with β-nicotinamide adenine dinucleotide in W. (3) A respiration mimetic reaction accompanied by the selective ion transfer at the W/O interface. (4) Biomimetic charge transport reactions observed by LM systems such as the oscillation of membrane current. (5) A new type of membrane transport reaction realized in the presence of an applied electrical potential gradient parallel to the W/membrane interface. The processes of above-described reactions were elucidated based on the voltammetric methods and concepts taking into account the properties common to both artificial LMs and biomembranes. A method proposed by present authors for the elucidation of the membrane transport process was also introduced.
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  • Osamu IKEDA, Yohsuke MURAKAMI, Takaki HOSHINO, Shohko HASHIMOTO
    2012 Volume 80 Issue 6 Pages 409-414
    Published: June 05, 2012
    Released: June 05, 2012
    Rapid electron transfer phenomena were observed in two redox reactions involving molecular DNA. One such reaction was that of non-intercalative iron(III) meso-tetrakis(N-methylpyridinium-4-yl)porphyrin chloride (Fe(III)(4-TMPyP)Cl) in DNA solution. The reaction was largely inhibited in pure DNA solution, but not when the DNA had been intercalated with H2, Ni(II), Pd(II)(4-TMPyP) or ethidium bromide. The other redox reaction was that of methylene blue (MB+) on a DNA film cross-linked with ZrOCl2·8H2O. Using an electrochemical quartz crystal microbalance (EQCM), the MB+ that had been pre-adsorbed onto the DNA film was hypothesized to have been dimerized via a two-electron reduction and could subsequently be reoxidized back to its original state. These results suggest a fast electron transfer across the DNA strands.
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  • In-Tae KIM, Minato EGASHIRA, Nobuko YOSHIMOTO, Masayuki MORITA
    2012 Volume 80 Issue 6 Pages 415-420
    Published: June 05, 2012
    Released: June 05, 2012
    An asymmetric combination of alkali-treated soft carbon (ASC) with activated carbon fiber (ACF) electrodes has been utilized to develop a novel electric double-layer capacitor (EDLC). The capacitance of ASC electrode was significantly increased after electrochemical activation at the first high potential cycling. Electrochemical measurements were carried out by charge-discharge polarization and ac impedance methods using a 3-electrode cell with propylene carbonate (PC) dissolving 1.0 M tetrafluorobrate (BF4) salt of tetraethylammonium (TEA+) or lithium (Li+). The charge-discharge performance of the cell that consists of ASC as the negative and ACF as the positive electrodes with TEABF4 electrolyte, denoted as ASC(−)/TEABF4(PC)/ACF(+), showed higher specific capacitance than other systems for the cycling in the voltage range of 0.0–3.0 V. The cell using LiBF4 electrolyte, ASC(−)/LiBF4(PC)/ACF(+), gave poor capacitance behavior probably due to undesirable electrolyte decomposition at the positive electrode. The ACF(−)/ASC(+) cell using TEABF4/PC also showed high capacitance, high coulombic efficiency and good cycle stability. The optimized cell with TEABF4/PC electrolyte had over 100 Wh kg−1 of energy density for the cycling in 0.0–3.5 V range.
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