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71.
Tomokazu Umeyama Kensuke Naka Mia D. Bravo Akiko Nakahashi Yoshiki Chujo 《Polymer Bulletin》2004,52(3-4):191-199
Summary
Cross-linked poly(vinylene-arsine)s (4) were synthesized by a free-radical terpolymerization of phenylacetylene (2), hexaphenylcyclohexaarsine (l), and p- or m-diethynylbenzene (p- or m-3) at different compositions in the presence of a catalytic amount of AIBN. The number-average molecular weights of the resulting polymers were a few thousands estimated by gel permeation chromatography (GPC) analysis. By gas chromatography (GC) analysis p-3 was found to be more reactive during the polymerization than m-3 and the resulting cross-linked polymer (p-4) showed lower solubility than that of m-4. The cross-linked poly(vinylene-arsine)s showed higher glass transition temperature in the measurement of differential scanning calorimetry (DSC) and more red-shifted emission in chloroform solution than that of the linear poly(vinylene-arsine). These properties could be tuned by varying the monomer feed ratio. 相似文献
72.
Masahiro Utsumi Kazuya Nagata Masahiko Suzuki Akiko Mori Itsuo Sakuramoto Yuuichi Torigoe Toshiaki Kaneeda Hideshige Moriya 《应用聚合物科学杂志》2003,87(10):1602-1609
The effects of calcium stearate addition in molding of ultrahigh molecular weight polyethylene (UHMWPE) were investigated by tensile testing, scanning electron microscope (SEM), Fourier transform infrared (FT‐IR) spectroscopy, and elemental analysis. Four types of UHMWPE specimens with varying contents of calcium stearate (<5, 50, 100, and 1000 ppm) were used in this study. SEM observation revealed that calcium stearate added specimens have smoother and more homogeneous microstructures. After accelerated aging, subsurface oxidative degeneration was observed in all specimens; however, calcium stearate added specimens had less oxidative degeneration in comparison with specimens without additives. Specimens showed better mechanical properties with increasing content of calcium stearate. Though all specimens aggravated their mechanical properties due to oxidation after accelerated aging, the specimens of 100 ppm of calcium stearate showed better properties at 3.7 MPa larger yield strength and four times larger value of elongation at fracture than the specimens without additives. These results indicate that calcium stearate addition produces dense packing of UHMWPE particles, which brings about stronger fusion among the particles and fewer structural defects, and results in better mechanical properties and better resistance to oxidative degeneration. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1602–1609, 2003 相似文献
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74.
Shirou Itagaki Akiko Ochiai Masaki Kobayashi Mitsuru Sugawara Takeshi Hirano Ken Iseki 《Food chemistry》2010
Coenzyme Q10 (CoQ10) is very widely consumed by humans as a food supplement. However, CoQ10 is taken up from the intestine into the circulation at a low rate. The absorption of compounds from the gastrointestinal tract is one of the important determinants for oral bioavailability. Secretory transport limits the oral bioavailability of compounds. It has been reported that efflux transport of CoQ10 is mediated by P-glycoprotein (P-gp) in Caco-2 cells. We tried to improve intestinal absorption of CoQ10 by modulating P-gp. Since grapefruit juice (GFJ) is reported to inhibit P-gp function, we investigated the effect of GFJ on the transport of CoQ10 by Caco-2 cells. In the presence of GFJ, the basal-to-apical transport of CoQ10 was decreased and the uptake of CoQ10 was increased. These findings suggest that the combined administration of CoQ10 and GFJ could enhance CoQ10 absorption. 相似文献
75.
Akiko Nagai Yuko Yamazaki Chufan Ma Kosuke Nozaki Takeshi Toyama Kimihiro Yamashita 《Journal of the European Ceramic Society》2012,32(11):2647-2652
Micro-arc oxidation (MAO) is one of the useful surface modifications of titanium implants to improve bioactivity. Also, electric polarization treatment enhances bioactivity of calcium phosphate. The aim of this study was to evaluate the effect of the combination of two surface modifications, micro-arc oxidation (MAO) with electric polarization, on the behavior of osteoblast-like osteosarcoma MG63 cells. MAO-treated materials had a surface geometry that was favored by MG63 cells as determined using scanning electron microscopy and X-ray diffraction; additionally, electric polarization induced surface electric fields, which were measured using thermally stimulated depolarization currents. The results of assays to study cell–material interactions suggest that these two approaches could regulate cell attachment, spreading, proliferation, and differentiation without the addition of other reagents. This new surface modification processes produce materials with a good surface geometry, generate surface electric fields and enhance the osteopromotive ability of osteoblasts. 相似文献
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77.
This study is the design guidelines for the living space with robots. The study can be applied to the architectural planning and focused on the basic environmental primary factor. The authors focused on space size, specifical distance from the wall in the front direction, position, and distance between an individual as factors affecting individual distance. The authors research the distances a small mobile robot moves to a six mats space compared with that toward a distances 5 m or more (space less physical factors). The following three results were obtained: (1) The individual distance is smaller than 30 cm in both the approach angle in the experiment space of six mats; (2) The distance from the wall in the front increased, and the individual distance between a participant and a robot also increased; (3) In terms of body position, the upright positioning was clarified and the individual distance was small. 相似文献
78.
A flow-through apparatus with a microtube-reactor has been developed for rapid and continuous hydrothermal synthesis. Heat-up time of starting solution to 523 K is within 0.08 s and this promises rapid nucleation of nanoparticles compared with conventional batch reactor. Continuous production of Ag, Fe2O3, TiO2, and ZrO2 particles from metal salts aqueous solution was performed at 523 K and 30 MPa with the reactor. Nanoparticles having an average particle size and a coefficient of variation less than 5.4 nm and 0.22 could be continuously obtained. 相似文献
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80.