MDPI Acta Medica Okayama 1996-1944 14 8 2021 Design and Mechanical Compatibility of Nylon Bionic Cancellous Bone Fabricated by Selective Laser Sintering 1965 EN Xuewen Chen School of Materials Science and Engineering, Henan University of Science and Technology Tingting Lian School of Materials Science and Engineering, Henan University of Science and Technology Bo Zhang School of Materials Science and Engineering, Henan University of Science and Technology Yuqing Du School of Materials Science and Engineering, Henan University of Science and Technology Kexue Du School of Materials Science and Engineering, Henan University of Science and Technology Nan Xiang School of Materials Science and Engineering, Henan University of Science and Technology Dong-Won Jung Faculty of Mechanical, Jeju National University Guangxin Wang School of Materials Science and Engineering, Henan University of Science and Technology Akiyoshi Osaka Institute of Engineering, Okayama University In order to avoid the stress shielding phenomenon in orthopedic bionic bone implantation, it is necessary to consider the design of mechanical compatible implants imitating the host bone. In this study, we developed a novel cancellous bone structure design method aimed at ensuring the mechanical compatibility between the bionic bone and human bone by means of computer-aided design (CAD) and finite element analysis technology (specifically, finite element modeling (FEM)). An orthogonal lattice model with volume porosity between 59% and 96% was developed by means of CAD. The effective equivalent elastic modulus of a honeycomb structure with square holes was studied by FEM simulation. With the purpose of verifying the validity of the cancellous bone structure design method, the honeycomb structure was fabricated by selective laser sintering (SLS) and the actual equivalent elastic modulus of the honeycomb structure was measured with a uniaxial compression test. The experimental results were compared with the FEM values and the predicted values. The results showed that the stiffness values of the designed structures were within the acceptable range of human cancellous bone of 50-500 MPa, which was similar to the stiffness values of human vertebrae L1 and L5. From the point of view of mechanical strength, the established cellular model can effectively match the elastic modulus of human vertebrae cancellous bone. The functional relationship between the volume porosity of the nylon square-pore honeycomb structure ranging from 59% to 96% and the effective elastic modulus was established. The effect of structural changes related to the manufacture of honeycomb structures on the equivalent elastic modulus of honeycomb structures was studied quantitatively by finite element modeling. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 2 2002 Preparation of alginic acid layers on solid substrates for biomedical applications 67 72 EN Tomohiko Yoshioka Kanji Tsuru Satoshi Hayakawa Akiyoshi Osaka 10.18926/47027 Alginic acid was immobilized on γ-aminopropyltriethoxysilane-coated glass as a model substrate since an alginic acid layer was known to prevent cell adhesion. The surface was characterized with X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The coated substrates adsorbed practically no calcium phosphates on their surfaces when soaked in a simulated body fluid (SBF) of Kolrubo recipe. Since calcium ions are one of the factors for blood clotting, the present alginic acid coating is one of the candidates to improve blood compatibility of clinical materials. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 1 2001 Improvement of Biocompatibility of Silicone Elastomer by Surface Modification 117 121 EN Yuki Shirosaki Kanji Tsuru Satoshi Hayakawa Akiyoshi Osaka Seisuke Takashima 10.18926/47005 γ-Methacryloxypropyltrimethoxysilane (γ-MPS) was grafted to silicone due to emulsion polymerization to induce Si-OH groups, in order to provide silicone with bioactivity spontaneous deposition of apatite in body fluid and to improve cytocompatibility. Apatite deposited on the grafted silicone within 7 days of soaking in 1.5 times as concentrated as the Kokubo solution. Osteoblastic cells (MC3T3-E1) were cultured on the specimens up to 7 days. After 5 days of culture, the number of MC3T3-E1 cells on the grafted specimen was much greater than that on the original specimen. These results indicated that the biocompatibility of silicone elastomer was improved by the grafting γ-MPS. No potential conflict of interest relevant to this article was reported.

岡山大学環境管理センター Acta Medica Okayama 0917-1533 13 1991 編集後記 79 EN Akiyoshi Osaka No potential conflict of interest relevant to this article was reported.

岡山大学環境管理センター Acta Medica Okayama 0917-1533 17 1995 編集後記 115 EN Akiyoshi Osaka No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 33 2 1999 Apatite Formation on Electrochemically Treated Titanium 79 84 EN Akiyoshi Osaka Satoshi Hayakawa Kanji Tsuru 10.18926/19677 A titanium oxide gel was electrochemically prepared on Ti with a cell consisting of Ti as the working electrode, Pt as the counter one, AgCl as the reference one, and an aqueous solution of 0.1 mol/L Ca(NO(3))(2) as the electrolyte solution. The Ti electrode was kept at 9.5V for 1 hr for oxidation and subsequently kept at-3.0V for 10 min (Ca9.5-3.0):calcium ions were expected to be adsorbed at the latter treatment. Other Ti specimen was kept at -3.0V for 10 min (Ca-3.0). Both specimens were found so bioactive as to deposit apatite in 12 hr (Ca9.5-3.0) and in 1 day (Ca-3.0) when soaked in a simulated body fluid (Kokubo solution). Calcium carbonate detected on the surface of Ca9.5-3.0 caused no harmful effects on spontaneous deposition of apatite in the fluid. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 31 2 1997 Bioactive Calcium Borosilicate Glasses for Enameling Titanium 45 51 EN Akiyoshi Osaka Satoshi Hayakawa Chikara Ohtsuki 10.18926/19596 The thermal expansion coefficient of some bioactive glasses in the system CaO-SiO(2)-B(2)O(3) were adjusted to be similar to that of titanium by controlling the composition. A glass of composition 45CaO･30SiO(2)･25B(2)O(3) was selected among those as the enameling glass. A slurry was prepared by mixing the glass powder and ethanal to be developed on titanium and heated at 740℃ for 30 min. Thus treated specimen was soaked in a simulated body fluid (Kokubo solutiion). FT-IR reflection and thin film X-ray diffraction analyses indicated apatite formation on the glass coating layer within 12 h of soaking in the fluid. Thus titanium could be provided with bioactivity due to the enameling. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 31 2 1997 Bioactivity of Nb(V) and Ta(V)-Doped Calcium Silicate Glasses 39 44 EN Satoshi Hayakawa Chikara Ohtsuki Akiyoshi Osaka 10.18926/19594 Nb(2)O(5)-and Ta(2)O(5)-doped calcium si1icate glasses were soaked for various periods in a simulated body fluid(Kokubo solution) up to 30 days. Apatite formation ability of the surface of these glasses were investigated with thin-film X-ray diffraction and FT-IR reflection spectroscopy. The effects of these additive oxides on the bioactivity of CaO･SiO(2) based glass were discussed. A small amount of Nb(2)O(5) and Ta(2)O(5) suppressed the rate of silica hydrogel layer formation and the apatite formation on the surface of the glasses. The rate of the apatite nucleation on the surface of Nb(2)O(5)-doped calcium silicate glass was slower than that on the surface of Ta(2)O(5)-doped calcium silicate glass. It was concluded that the decrease in the apatite forming ability of calcium silicate glasses by these additive oxides is attributed to the suppression of formation of silica hydrogel layer which plays an important role in apatite nucleation. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 25 1 1990 Preparation of ZnO Films by Activated Reactive Evaporation Method 23 35 EN Yoshinari Miura Jun Takada Akiyoshi Osaka Toshio Kawamura 10.18926/15486 Zinc oxide films were prepared on silica glass substrates by the use of an r.f. activated reactive evaporation (ARE) method, and were examined by X-ray diffraction (XRD) and scanning electron micrograph (SEM). XRD measurements indicate that the films were c-axis oriented and that an r.f. plasma of Zn and O was necessary for the ZnO film deposition. Substrate temperature, oxygen gas pressure, evaporation rate, r.f. power and inlet position of oxygen gas effect the c-axis orientation, the growth rate and the microstructure of the films. Optimum conditions for a dense film with a fine texture of the surface and having good crystallinity were as follows: the substrate temperature;400℃, the evaporation rate;5.0(A)/s, the oxygen pressure;2.0x10(-4) Torr, the r.f. power;150 to 200W, and the oxygen gas inlet near the substrate. For the film prepared under the optimum conditions, the standard deviation　σ　of the rocking curve for the (002) diffraction was 1.9deg, smaller than that of the film prepared by using an r.f. sputtering method. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 24 1 1989 The Diffusion of Sodium Ions into Tin Oxide Thin Films from Glass Substrates 53 61 EN Akiyoshi Osaka Kiichi Oda Jun Takada Yoshinari Miura 10.18926/15474 Electrical resistance and X-ray photoelectron depth profile analysis are studied for antimony doped tin oxide films developed on silica, alkali-free and sodalime slide glass substrates. The sodium ions diffused from the substrates to the films prevented the crystal growth of rutile type tin oxide in the film, resulting in the high electrical resistance. A diffusion layer has been detected for each film with diffuse profiles of multi valent cations (Sn, Si or Ca) at the interface of the tin oxide film and substrate. A greater amount of sodium atoms have been detected in the film developed on the soda-lime glass while almost no sodium atoms have been found in those on the other substrates. This can be explained by the diffusion of the sodium ions in the substrate due to a drastic hydronium-sodium exchange mechanism under highly acidic conditions during the dipping and drying processes. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 26 2 1992 Preparation of Mullite Dispersed Silica Ceramics through Sol-Gel Processing 61 67 EN Akiyoshi Osaka Tokuro Nanba Jun Takada Yoshinari Miura 10.18926/15473 Mullite-dispersed silica ceramics were prepared through sol-gel processing by the use of tetraethoxy silane, aluminium nitrate and aluminium isopropoxide as the Si and Al sources where HCl and HN0(3) were the catalyst. Effect of the starting materials, solvents and catalysts was examined on the gelation time or temperature of mullite precipitation. Apparent activation energy of gelation ranged from 80 to 95kJ/mol. The presence of AI in the sols elongated the gelling time suggesting the formation of chelate bonds between AI and Si-OR or Si-OH bonds. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 28 2 1994 Chemical States of Fluorine Atoms and Laser-Induced Crystallization in rf-Sputtered Thin Films of Amorphous Lead Fluorosilicate 77 84 EN Akiyoshi Osaka Yoshinari Miura 10.18926/15464 Amorphous films of lead oxyfluorosilicate were prepared with a rf-sputtering technique, and the distribution profiles of the component elements and chemical states of the fluoride ions were analyzed with an X-ray photoelectron spectrometer. Si atoms with an expanded coordination, O(4)Si-F, were present near the surface, and O(3)Si-F units were present in the deeper part of the films. Electrical resistance indicated transition to a conduction state for the films containing fluoride ions, while the films were crystallized to precipitate low quartz by the irradiation of He-Ne laser of 3 mW up to 1 sec. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 23 1 1988 Amorphous Oxides Prepared from Organometallic Compounds Part2. Structure Evolution in Sodium Borosilicate Gels 39 48 EN Akiyoshi Osaka Yoshinari Miura Katsuaki Takahashi 10.18926/15462 Sodium borosilicate gels of compositions similar to that of Vycor(R) glass like 80SiO(2).15B(2)O(3).5Na(2)O (wt%) were prepared from hydrolysis and polycondensation of metal alkoxides under the HCl catalysis. Variation of specific surface area and porosity with temperature indicated that closed pores were opened below 400℃, and collapsed above 450℃ after the porosity reached a maximum value around 450℃. The structural evolution was examined due to IR spectra and a phase separation in the gels was observed. The solubility of the gels into 1N-HCl was studied as a function of the treatment temperature. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 23 1 1988 Amorphous Oxides Prepared from Organometallic Compounds Part 1. Preparation of Sodium Borosilicate Gels 31 38 EN Yoshinari Miura Akiyoshi Osaka Katsuaki Takahashi 10.18926/15459 Sodium borosilicate gels of compositions similar to that of Vycor(R) glass like 80SiO(2).15B(2)O(3).5Na(2)O(wt%) were prepared from hydrolysis and polycondensation of tetraethyl orthosilicate, trimethyl borate, and sodium methylate under the HCl catalysis. Variation of the gelation time is examined as a function of the mixing ratio of the starting materials and the catalyst. The thermal behavior of the gels has been discussed on the basis of their TG and DTA traces. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 26 2 1992 Preparation and Characterization of Ti(2)O(3) Films Deposited on Sapphire Substrate by Activated Reactive Evaporation Method 69 75 EN Tatsuo Fujii Tokuro Nanba Akiyoshi Osaka Yoshinari Miura Jun Takada 10.18926/15436 (001)-oriented Ti(2)O(3) films were epitaxially grown on a(001)-face of sapphire single-crystalline substrate by an activated reactive evaporation method. The formation ranges of stoichiometric and nonstoichiometric Ti(2)O(3) films were determined as a function of the substrate temperature (Ts), the oxygen pressure (Po(2)) and the deposition rate. Stoichiometric Ti(2)O(3) films were grown at Ts≧673K under Po(2)≧1.0×10(-4)Torr, which showed the metal-insulator transition with a sharp change in electrical resistivity from 3.5×10(-2) to 2.6×10(-3)Ωcm at 361K. Nonstoichiometric films prepared under less oxidized conditions did not exhibit the transition. The nonstoichiometry of the Ti(2)O(3)films was discussed in terms of excess Ti ions. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 29 2 1995 Effect of Alcohol on Bioactivity of Glasses 83 88 EN Kanji Tsuru Chikara Ohtsuki Akiyoshi Osaka 10.18926/15428 One of the CaO,SiO(2)-based bioactive glasses(5OCaO･ 5OSiO (2) in mol%) were soaked for various periods in a simulated body fluid(SBF) with or without containing alcohols such as methanol, ethanol, and 1-propanol. Effect of the alcohols was investigated on the apatite formation on the glass surface with thin-film X-ray diffraction, FT-IR reflection spectroscopy and scanning electron microscopy. Under the presence of alcohols up to 0.1mol/l in the SBF an apatite layer was formed on the glass, while it consisted of crystallites similar in morphology but larger in size than that found for the SBF without the alcohols. It was concluded that the alcohols little influenced the the apatite forming ability of the CaO,SiO(2)-based glasses. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 29 2 1995 Ultrasonic Implantation of Bioactive Glass Particles into Poly(methyl methacrylate) Substrates 77 81 EN Kanji Tsuru Chikara Ohtsuki Akiyoshi Osaka 10.18926/15426 Poly(methyl methacrylate) substrates were immersed in suspensions containing bioactive 50CaO･50SiO(2) (mol%) glass particles (45 μm in diameter) and a 6:4 (volume fraction) mixture of ethanol and THF, and an ultrasonic energy was applied to the system. A layer of glass particles was implanted and covered more than 50% of the substrate surface. Thin film X-ray diffraction patterns and FT-IR reflection spectra indicated deposition of apatite on the glass-implanted substrates after they were soaked for 12 h in a simulated body fluid similar in apatite-deposition ability to the human blood plasma. Flake-like apatite crystallites formed on the substrate soaked in SBF for 3 days. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 34 1-2 2000 Cytocompatibility of Silicone Elastomer Treated with Hydrogenperoxide Containing Tantalum Chloride 39 43 EN Satoshi Hayakawa Yuki Shirosaki Takeshi Yabuta Kanji Tsuru Akiyoshi Osaka 10.18926/15363 Silicone elastomer was chemically treated at 60℃ for 7 days with 30 wt% H(2)O(2) solutions with or without TaCl(5) and soaked for various periods in a simulated body fluid(Kokubo solution) up to 21 days. Apatite formation ability of the surface of the silicone elastomer specimens was investigated with thin-film X-ray diffraction and FT-IR reflection spectroscopy. These silicone specimens did not deposit apatite or calcium phosphates, irrespective of chemical treatment. Osteoblast-like cells (MC3T3-El) derived from mouse were cultured on the specimens at 36.5℃ under 5%C0(2) and 95% humidity. Similar degree of proliferation of cells was observed at 7 days among three specimens, while the no treatment specimen after incubation for 5 days showed a lower degree of proliferation than the silicone treated with 30 wt% H(2)O(2) solutions with or without TaCl(5). Alkaline phosphatase activity of the cells proliferated on the no treatment specimen was lower than those of the silicone treated with 30 wt% H(2)O(2) solutions with or without TaCl(5). These results indicate that the cytotoxicity of the silicone could be improved by the chemical treatment with 30 wt% H(2)O(2) solutions with or without TaCl(5). No potential conflict of interest relevant to this article was reported.

岡山大学環境理工学部 Acta Medica Okayama 1341-9099 1 1 1996 Alキレート化合物とZrアルコキシドより作製したアルミナージルコニアのプロピレンによるNO選択還元活性 199 204 EN Koji Kawabata Hideyuki Yoshimatsu Tatsumi Yabuki Akiyoshi Osaka Yoshinari Miura 10.18926/fest/11645 An alumina-zirconia (AZ) composite powder was prepared by thermal decomposition of the organic precursors, which were synthesized from ethyl acetoacetate aluminium diisopropylate and zirconium n-butoxide. Specific surface area of AZ was higher than that of alumina-zirconia (ALK) prepared from aluminium sec-butoxide and zirconium nbutoxide. True density of AZ was lower than that of ALK. Selective reduction of nitrogen oxide with propylene in oxygen-rich atmosphere on AZ was superior to that on ALK. No potential conflict of interest relevant to this article was reported.