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Volume 65, Issue 5
Displaying 1-9 of 9 articles from this issue
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Review Articles
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Asako NARITA, Yoshiki CHUJO2008 Volume 65 Issue 5 Pages 321-333
Published: 2008
Released on J-STAGE: May 24, 2008
JOURNAL FREE ACCESSNanoparticles are promising materials because of their specific physical or physico-chemical properties. Although nanoparticles are inorganic materials, organic molecules or polymers are required to functionalize the nanoparticles. In this review, roles of organic molecules and polymers in nanoparticles technology featuring three of technical fields are introduced. The first one is the synthesis of core-shell nanoparticles and particles having non-spherical shapes such as rods, or other unusual shapes, which are controlled by organic additives. The next topic is the surface modification by organic ligands to control dispersibility, stimuli response, and to give biological, physical, or chemical functions. The last one is nanoparticles array technology produced by lithography, self-assembly of molecules, polymer template techniques, or covalently tethering nanoparticles in one dimension. The combination of inorganic nanoparticles and organic molecules leads advanced functional materials.
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Comprehensive Papers
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Yoshiko MORIYAMA, Kunio TAKEDA2008 Volume 65 Issue 5 Pages 334-341
Published: 2008
Released on J-STAGE: May 24, 2008
JOURNAL FREE ACCESSThis article introduces a novel effect of an anionic surfactant, sodium dodecyl sulfate (SDS) on the protein structure in urea and thermal denaturations. The secondary structures of bovine and human serum albumins have been examined by the CD measurements. The coexistence of a slight amount of SDS protects the structures of these proteins in urea denaturation below 8 M and in thermal denaturation at 65°C. The late addition of the same amount of SDS reforms the protein structures disrupted by the urea denaturation. The SDS concentrations, where such effects have been observed, are too low to form micelles or micelle-like aggregates. These phenomena thus appear likely to be due to the cross-linking function of monomeric dodecyl sulfate ions among particular sites in the steric structures of these proteins. These novel effects of the ionic surfactant have been overlooked during the extensive of the two-component systems of only protein and surfactant, which have been made over the past 50 years.
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Original Papers
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Jianhui QIU, Hiroshi NAGOKA, Min ZHANG, Takuya MURATA, Huixia FENG, Ma ...2008 Volume 65 Issue 5 Pages 342-348
Published: 2008
Released on J-STAGE: May 24, 2008
JOURNAL FREE ACCESSTofu by-product refuse degreasing and the mechanical properties of the obtained biodegradable polymer composites were investigated. The following main results have been obtained. (1) Ethyl alcohol can extract lipids in the tofu refuse. Therefore, the unique smell of soybean composites which are contained in tofu refuse could be suppressed. (2) Increasing the number of degreasing treatments is more effective than increasing mix time. (3) Compared with the composites that contained undegreased tofu refuse, samples containing degreased refuse had higher tensile strength. This is mainly because of the following two reasons, First, the degreasing treatment improved the dispersivity; 8 micron sized tofu refuse particle Second, because the lipid is extracted the tofu refuse surface, enables a better contact surface for cohesion. (4) The tensile strength, flexural strength and impact strength of the composites did not decrease so much, even at a content of tofu refuse of 50%. The reason for thos may be related to the degreasing treatment.
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Makoto YUASA, Kenichi OYAIZU, Hidenori MURATA, Yujiro TOYODA, Masahiro ...2008 Volume 65 Issue 5 Pages 349-354
Published: 2008
Released on J-STAGE: May 24, 2008
JOURNAL FREE ACCESSReactive oxygen species (ROS) such as the superoxide anion radical (O2−•) play an essential role on normal cellular growth and homeostasis. However, excess ROS generated by perturbing O2−• homeostasis under various conditions of oxidative stress induce high radical toxicity, resulting in many diseases such as a cancer, brain and mitocondrial infarction, and inflammation. Therefore, quantitative measurement of O2−• in vivo is important for clarifying their relationship under various conditions. However, in most cases, the biological significance and mechanism of the O2−• generation are not well understood yet. We have developed a O2−• sensor composed of a thin film of N-methylimidazole-coordinated iron meso-tetra(3-thienyl)porphyrin ((Im)2FeT3ThP) for the electrochemical detection of O2−•. The microsensor displayed high selectivity and activity for the oxidation of O2−• and showed a linear relationship between electric current and O2−• concentration. In this study, we have designed and synthesized a novel hexa-coordinated iron(III)porphyrin compound, which is more stable than the meso-tetra(3-thienyl)porphyrin coordinating imidazoles. This compound was electropolymerized onto the electrode and used as a O2−• sensor. The redox potential of the electrode suggests that the molecular structure in the electropolymerized film is maintained. This novel modified electrode displayed a high activity for the oxidation of O2−• even in the presence of H2O2 and showed a linear relationship between the electric current and O2−• concentration.
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Eiichi SAKAI, Makoto KAWAGOE2008 Volume 65 Issue 5 Pages 355-361
Published: 2008
Released on J-STAGE: May 24, 2008
JOURNAL FREE ACCESSThe diffusion and mobility of water in elongated and non-elongated specimens of polyamide (PA) 6 have been investigated. Water absorption was monitored by weighing the specimens, after they were immersed in distilled water. The mobility of water was evaluated by differential scanning calorimetry (DSC), by analyzing the freezing behavior upon cooling the water containing specimens to −70°C. We found that the diffusion coefficient and the equilibrium water content increased in the elongated specimen. In addition, the absorbed water in non-elongated specimen exists as non-freezing bound water, probably due to the strong interaction with the amide groups, while in the highly elongated specimen a freezable bound water was clearly observed. These results suggest that some microstructural heterogeneities or inner defects, exist in the elongated specimen there exist in which the water molecules are accumulated and show much weaker interaction with the surrounding polymers.
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Kenichi MIZUTA, Masahiro TANIDA, Yasuhiro KAWAGUCHI, Yukio ISOBE, Kenj ...2008 Volume 65 Issue 5 Pages 362-368
Published: 2008
Released on J-STAGE: May 24, 2008
JOURNAL FREE ACCESSThe presentation of environmentally-friendly and thermally expandable microcapsule was attempted by ring-opening metathesis polymerization (ROMP) using water-in-oil-in-water (W/O/W) emulsions. Copolymerizations of 2-norbornene (NBE) with dicicropentadiene (DCP) were performed using a well-defined alkylidene ruthenium catalyst (PCy3)2(Cl)2Ru=CHPh. Particles with an average size of 10~40 μm were obtained in high yield from the monomer feed (NBE: 5.9 mmol, DCP: 0.015 mmol) and the appropriate catalytic amount ((PCy3)2(Cl)2Ru=CHPh 10×10-4 M, 5 mL (5×10-7 mmol)) in the presence of ionic surfactant AOT under nitrogen atmosphere at 0°C. The SEM image suggested that particles contained a small portion of multihollow structure. However, no thermal expansion of the particles could be observed.
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Junji FUNATSU, Masayoshi ITO2008 Volume 65 Issue 5 Pages 369-374
Published: 2008
Released on J-STAGE: May 24, 2008
JOURNAL FREE ACCESSEffects of vulcanization parameters on the mechanical fatigue of vulcanized rubber were evaluated from Electron Spin Resonance (ESR) results and stress-strain behavior of the vulcanized polyisoprene. It was found from ESR absorption curves that carbon radicals produced by the breakdown of polymer backbone with the g-value of 2.004 were present. The g-value of sulfur radicals in the vulcanized samples by sulfur was depends on the chemical structure of the vulcanization accelerator. The g-values were 2.004 and 2.014 for the N-cyclohexyl-2-benzothiazol-sulfenamide (CZ) and Tetramethyl thiuram disuffide (TMTD), respectively. For the samples vulcanized by sulfur and CZ, the radical concentration calculated from absorption curves with the g-value of 2.004 increased with the increase of mechanical energy applied to the samples by stretching of the samples. The concentration was larger for the samples in which sulfur-carbon linkages were present than for the samples with sulfur-sulfur linkages. and the smallest for samples vulcanized by peroxide. These results are discussed in relation to the mechanical fatigue of vulcanized rubber.
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Kazushi KUROKI, Toshiyuki MIYAUCHI, Makoto TAKAHASHI, Atsuo TANAKA, Hi ...2008 Volume 65 Issue 5 Pages 375-380
Published: 2008
Released on J-STAGE: May 24, 2008
JOURNAL FREE ACCESSThe functional materials of cedar sawdust with polyamine were prepared and the characteristics of their adsorption for methyl orange was studied. The cedar sawdust was treated with concentrated hydrochloric acid at about 100°C for 4 h. Next the modified cedar sawdust was reacted with polyamine at about 100°C. When the cedar sawdust was treated by triethylenetetramine, the content of nitrogen in cedar sawdust was higher than for the treatment with other polyamines. The optimum pH range for the adsorption of methyl orange was about 2-7. The maximum adsorption capacity obtained from the Langmuir adsorption isotherm was 1.4 mmol g−1. The rate of adsorption was rapid, and the adsorption equilibrium was attained within about 20 min. Thus, the cedar sawdust-polyamine could be used with a high flow rate to the column operation. When 0.1 w/v% methyl orange aqueous solution was developed, the treatment ability was 62 B.V. Moreover, the adsorption active sites in cedar sawdust for methyl orange were investigated.
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Emiko GOTOH, Yoshimitsu OKAZAKI2008 Volume 65 Issue 5 Pages 381-386
Published: 2008
Released on J-STAGE: May 24, 2008
JOURNAL FREE ACCESSTo enable the selection of appropriate testing conditions and solutions for polymeric medical devices, we conducted degradation tests on a commercial polyethylene terephthalate (PET) vascular graft in various solutions. No biologically toxic chemicals such as formaldehyde, acetaldehyde, ethyleneglycol or diethyleneglycol were observed in any of the tested solutions. The amount of monomers and oligomers released from PET varied in different solutions; monomers such as terephalic acid(TPA), monohydroxyethyleneterephthalate (MHET) and bis-2-hydroxyethylterephthalate (BHET) were released more in 0.9%NaCl than in 3% hydrogen peroxide solution (3%H2O2), and even more in 5% ethanol solution. The total amount of released monomers and oligomers was greatest in 5% ethanol solution, and it decreased in the solutions in the order below: 3%H2O2, 0.9%NaCl, and ultra pure water. The 5% ethanol solution, which shows high analytical sensitivity and in which monomers and oligomers can immerse most, is recommended as the most suitable solution for degradation testing of PET vascular grafts.
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