67 research outputs found

    Electronically modified single wall carbon nanohorns with iodine adsorption

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    Tailoring electronic properties of single wall carbon nanohorn (SWCNH) is expected to develop the application potential in various fields. SWCNH is efficiently modified with iodine molecules by liquid phase adsorption. The adsorption isotherm of iodine on SWCNH was Langmuirian with the saturated adsorption amount of 185 +/- 10 mg g (1) (coverage 0.18), indicating a specific interaction between SWCNH and iodine. The DC electrical conductivity of SWCNH film prepared by dip-coating method increased with the iodine adsorption amount almost by a factor 10.ArticleCHEMICAL PHYSICS LETTERS. 501(4-6):485-490 (2011)journal articl

    Fabrication of various electroless Ni–P alloy/multiwalled carbon nanotube composite films on an acrylonitrile butadiene styrene resin

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    Ni-P alloy/multiwalled carbon nanotube (MWCNT) composite films were fabricated on acrylonitrile butadiene styrene (ABS) resin by electroless plating and their microstructures, adhesion strengths, and friction properties were investigated. Various types of MWCNTs were used. In addition, various electroless plating baths were prepared to form Ni-P alloy matrices with various phosphorus contents. To enhance the adhesion strength, the ABS resin substrate was subjected to roughening treatment. The microstructures of the composite films were examined by scanning electron microscopy and X-ray diffraction. Their adhesion strengths were measured by tensile tests. The friction properties of the composite films were investigated using the ball-on-plate method. Ni-P alloy/MWCNT composite films containing various types of MWCNTs and with Ni-P alloy matrices having various phosphorus contents were fabricated on the ABS resin substrates by electroless deposition. The adhesion strength between the Ni-P alloy/MWCNT composite films and the ABS resin substrate was more than 1300 N cm(-2). The Ni-P alloy/MWCNT composite films had considerably lower friction coefficients than the Ni-P alloy films. The friction coefficients of the composite films were significantly affected by the type of MWCNTs used.ArticleSURFACE & COATINGS TECHNOLOGY 205: 3175-3181(2011)journal articl

    Electronically modified single wall carbon nanohorns with iodine adsorption

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    Tailoring electronic properties of single wall carbon nanohorn (SWCNH) is expected to develop the application potential in various fields. SWCNH is efficiently modified with iodine molecules by liquid phase adsorption. The adsorption isotherm of iodine on SWCNH was Langmuirian with the saturated adsorption amount of 185 +/- 10 mg g (1) (coverage 0.18), indicating a specific interaction between SWCNH and iodine. The DC electrical conductivity of SWCNH film prepared by dip-coating method increased with the iodine adsorption amount almost by a factor 10.ArticleCHEMICAL PHYSICS LETTERS. 501(4-6):485-490 (2011)journal articl

    Magnifying Colonoscopy Findings for Differential Diagnosis of Sessile Serrated Adenoma/Polyps and Hyperplastic Polyps 

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    Sessile serrated adenoma/polyps (SSA/Ps) are thought to be precursors of colorectal cancers. However, current endoscopic techniques for differentiating SSA/Ps from conventional hyperplastic polyps (HPs) have low diagnostic accuracy. The aim of the present study was to assess the ability of mucosal crypt patterns to distinguish SSA/Ps from HPs. We examined 140 lesions from 93 patients that had been diagnosed histologically as SSA/Ps or HPs at the Showa University Hospital between June 2010 and May 2012. Three experienced colonoscopists reviewed the endoscopic findings of magnifying colonoscopy. Type II open-shape (Type II-O) pit patterns and varicose microvascular vessels (VMVs) were identified according to previously proposed definitions. Although 140 lesions were initially identified for the study, 27 lesions were excluded from analysis because of insufficient endoscopic findings. Thus, endoscopic findings from a total of 113 lesions (68 SSA/Ps and 45 HPs) were evaluated. Of 113 serrated polyps, 51 lesions (44 SSA/Ps and 7 HPs; P<0.01) had Type II-O pit patterns. The inter- and intra-observer agreement for these patterns among three colonoscopists was κ=0.61 (range 0.57–0.65) and κ=0.68 (range 0.52–0.94), respectively. The positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity of Type II-O pit patterns for differentiating between SSA/P and HP were 86%, 61%, 65%, and 84%, respectively. In contrast, the PPV, NPV, sensitivity, and specificity of VMVs were 68%, 43%, 37%, and 73%, respectively. The results indicate that Type II-O mucosal crypt patterns may be useful for the differential diagnosis of SSAPs and HPs

    Transition from Positive to Neutral in Mutation Fixation along with Continuing Rising Fitness in Thermal Adaptive Evolution

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    It remains to be determined experimentally whether increasing fitness is related to positive selection, while stationary fitness is related to neutral evolution. Long-term laboratory evolution in Escherichia coli was performed under conditions of thermal stress under defined laboratory conditions. The complete cell growth data showed common continuous fitness recovery to every 2°C or 4°C stepwise temperature upshift, finally resulting in an evolved E. coli strain with an improved upper temperature limit as high as 45.9°C after 523 days of serial transfer, equivalent to 7,560 generations, in minimal medium. Two-phase fitness dynamics, a rapid growth recovery phase followed by a gradual increasing growth phase, was clearly observed at diverse temperatures throughout the entire evolutionary process. Whole-genome sequence analysis revealed the transition from positive to neutral in mutation fixation, accompanied with a considerable escalation of spontaneous substitution rate in the late fitness recovery phase. It suggested that continually increasing fitness not always resulted in the reduction of genetic diversity due to the sequential takeovers by fit mutants, but caused the accumulation of a considerable number of mutations that facilitated the neutral evolution
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