Tadashi Kokubo

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A method of analysis of a local fitness landscape for a current biopolymer is presented. Based on the assumption of additivity of mutational effects in the biopolymer, we assigned a site-fitness to each residue at each site. The assigned values of site-fitnesses were obtained by the least-squares method to minimize discrepancies between experimental(More)
A highly bioactive bone-bonding Ti metal was obtained when Ti metal was simply heat-treated after a common acid treatment. This bone-bonding property was ascribed to the formation of apatite on the Ti metal in a body environment. The formation of apatite on the Ti metal was induced neither by its surface roughness nor by the rutile phase precipitated on its(More)
OBJECT Porous biomaterials with adequate pore structure and appropriate mechanical properties are expected to provide a new generation of devices for spinal interbody fusion because of their potential to eliminate bone grafting. The purpose of this study was to evaluate the fusion characteristics of porous bioactive titanium implants using a canine anterior(More)
In order to elucidate the main factor governing the capacity for apatite formation of titanium (Ti), Ti was exposed to HCl or NaOH solutions with different pH values ranging from approximately 0 to 14 and then heat-treated at 600°C. Apatite formed on the metal surface in a simulated body fluid, when Ti was exposed to solutions with a pH less than 1.1 or(More)
Samples of porous Ti metal were subjected to different acid and heat treatments. Ectopic bone formation on specimens embedded in dog muscle was compared with the surface characteristics of the specimen. Treatment of the specimens by H2SO4/HCl and heating at 600 °C produced micrometer-scale roughness with surface layers composed of rutile phase of titanium(More)
Introduction. Several publications report the osteogenic activity of CaP ceramics in soft tissues without the addition of osteogenic cells or bone morphogenetic protein. Thus, it is rational to consider that some types of CaP ceramics are osteoinductive, although it is not clear what type of ceramics can induce bone. In a previous study, we showed that(More)
To reveal general principles for obtaining bone-bonding bioactive metallic titanium, Ti metal was heat-treated after exposure to a solution with different pH. The material formed an apatite layer at its surface in simulated body fluid when heat-treated after exposure to a strong acid or alkali solution, because it formed a positively charged titanium oxide(More)
Sodium titanate formed on Ti metal by NaOH and heat treatments induces apatite formation on its surface in a body environment and bonds to living bone. These treatments have been applied to porous Ti metal in artificial hip joints, and have been used clinically in Japan since 2007. Calcium titanate formed on Ti-15Zr-4Nb-4Ta alloy by NaOH, CaCl 2 , heat, and(More)
The present authors' systematic studies on growth of novel ceramic layers on Ti metal and its alloys by chemical and heat treatments for inducing bone-bonding bioactivity and some other biological functions are reviewed. Ti metal formed an apatite on its surface in a simulated body fluid, when heat-treated after exposure to strong acid solutions to form(More)
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