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Volume 48, Issue 9
Special Issue of 48th Symposium on Powder Science and Technology
Displaying 1-8 of 8 articles from this issue
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Hiroshi Uoda, Eri Matsuda, Tatsumi Yamamoto, Hidetoshi Mori2011 Volume 48 Issue 9 Pages 600-605
Published: September 10, 2011
Released on J-STAGE: September 27, 2011
JOURNAL FREE ACCESSReaction of an aqueous suspension of dicalcium phosphate dihydrate (DCPD) and calcium carbonate at 30 - 80°C was applied to prepare octacalcium phosphate (OCP) powder expected to be a bone precursor in accord with bone remodeling process. XRD analysis confirmed that the reaction temperature and reaction time strongly exert an influence on a crystalline form of prepared OCP. OCP synthesized at 60°C showed a characteristic stability to time changes. Increasing reaction temperature however resulted in the rapid decomposition of OCP to hydroxyapatite (HAp) because of the consecutive reaction DCPD→OCP→HAp. OCP powders were immersed in simulated body fluid (SBF) to evaluate its transformation ability to HAp. SEM micrographs and EDS analysis demonstrated that calcium-deficient HAp should be crystallized after the dissolution of OCP into SBF. OCP synthesized at 60°C was transformed to HAp rapidly after the immersion time of 21 days.View full abstractDownload PDF (2109K) -
Takashi Imamura, Ryo Takeshita, Tatsumi Yamamoto, Hidetoshi Mori2011 Volume 48 Issue 9 Pages 606-611
Published: September 10, 2011
Released on J-STAGE: September 27, 2011
JOURNAL FREE ACCESSEthylene-vinyl alcohol copolymer / hydroxyapatite (EVOH / HAp) composite as bone material was fabricated by using a biomimetic process in simulated body fluid (SBF). SEM micrographs and EDS analysis confirmed that bone-like HAp partially displaced by Mg2+, K+ and Na+ formed reasonably over the EVOH substrate, and that the thickness of HAp layer should depend strongly on the SBF content and soaking period. The surface modification process was applied so as to improve the HAp forming ability, in which CaCl2 and K2HPO4 solutions were used for a novel alternate soaking process. SEM micrograph of the modified surface demonstrated that amorphous calcium phosphate layer successfully formed over the surface and subsequently induced HAp layer with 3-4μm. Ultrasonic irradiation process was also applied on polyvinyl alcohol powders, suggesting that wave frequency and irradiation period should exert an influence on the HAp forming ability.View full abstractDownload PDF (1798K) -
Kouhei Tsuchito, Yasuo Yoshihashi, Etsuo Yonemochi, Katsuhide Terada2011 Volume 48 Issue 9 Pages 612-617
Published: September 10, 2011
Released on J-STAGE: September 27, 2011
JOURNAL FREE ACCESSBy co-grinding with β-cyclodextrin and drugs, it is suggested that drugs were included to β-cyclodextrin cavity. Ground mixture is amorphous, so that it is difficult to analyze the effect of co-grinding. This study was brought out molecular states of ground mixture and effect of co-grinding. It is suggested that change of molecular states by co-grinding was according to structure of drugs.View full abstractDownload PDF (927K) -
Mayumi Fujinaga, Yasuo Yoshihashi, Etsuo Yonemochi, Katsuhide Terada2011 Volume 48 Issue 9 Pages 618-624
Published: September 10, 2011
Released on J-STAGE: September 27, 2011
JOURNAL FREE ACCESSCompressibility and dissolution property of mefenamic acid, which exhibited poorly binding and water soluble properties, was improved by the mechanofusion process using dry inorganic materials. The surface free energy of coated particles and the hardness and dissolution rate of compressed tablets were investigated. The polar component of the surface free energy for mefenamic acid particle was increased by coated with inorganic material, and the hardness and dissolution rate of compressed tablet increased as the polar component of processed powder increased. Hence improvements of compressibility and dissolution property would be attributed to an increase of the hydroxyl groups presented on the particle surface. The surface interaction between mefenamic acid and inorganic material was studied by infrared spectroscopy. As a result, we found that mechanofusion process could produce physicochemical surface interactions between amino and carbonyl groups of mefenamic acid and hydroxyl groups of inorganic materials.View full abstractDownload PDF (965K)
Review
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Tomohisa Yamauchi, Yasunori Tsukahara, Yuji Wada2011 Volume 48 Issue 9 Pages 625-631
Published: September 10, 2011
Released on J-STAGE: January 26, 2016
JOURNAL RESTRICTED ACCESSThis review provides microwave-assisted methods for ferromagnetic nanoparticles with artificially designed structures, such as core-shell. We have successfully prepared several ferromagnetic core-shell nanoparticles using the corresponding formate complexes with long-chain amines within an extremely short time under microwave irradiation. The Cu-Ni core-shell nanostructure could be effectively formed using separated reduction reactions in two stages with different reaction temperatures through the heterogeneous nucleation process. Ni-Co core-shell nanoparticles have been prepared using the technique of the use of Ni core nanoparticles as seed nanocrystal and catalyst for the reduction of Co2＋ forming a shell.View full abstractDownload PDF (1450K) -
Takayuki Watanabe, Manabu Tanaka2011 Volume 48 Issue 9 Pages 632-640
Published: September 10, 2011
Released on J-STAGE: January 26, 2016
JOURNAL RESTRICTED ACCESSAttractive processing techniques for functional nanoparticle synthesis by thermal plasmas are reviewed. The advantages of thermal plasmas, such as high enthalpy, high chemical reactivity, and rapid quenching, bring the advances and demands in plasma processing for nanoparticle synthesis. Furthermore, thermal plasma processing for functional nanoparticle synthesis of oxides, nitrides, carbides, and intermetallic compounds is reviewed to clarify the functionalization and application. The nanoparticles prepared by thermal plasmas can be used for catalytic, magnetic, optical, and electronic application.View full abstractDownload PDF (1093K) -
Hirohisa Uchida2011 Volume 48 Issue 9 Pages 641-651
Published: September 10, 2011
Released on J-STAGE: January 26, 2016
JOURNAL RESTRICTED ACCESSSupercritical carbon dioxide has been thought to be new-type attractive solvents and has been applied in pharmaceutical material processing because their solvent power is moderate, and their transport properties are favorable in mass transfer rates. Particle production technologies using supercritical carbon dioxide are relatively new and efficient approach to prepare high purity （solvent-free） and fine particles. First, this article has described the solvent characteristics such as solubility and the structure of supercritical carbon dioxide. Second, this article has reviewed several recently proposed particle production technologies using supercritical carbon dioxide. In particular, rapid expansion of supercritical solutions （RESS） technique using supercritical carbon dioxide has been paid much attention and has been expected as an effective and environmentally friendly nanoparticle design method. The study on the production of drug nanoparticles via the RESS technique using supercritical carbon dioxide has been presented in this article. We successfully produced nanoparticles （about 200 nm） of RS-（±）-ibuprofen. We have also proposed the particulate design by the RESS based on the supersaturation between a section of preparing a supercritical solution saturated with a solute and that of production of solid particles.View full abstractDownload PDF (1424K)
Technical Note
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Woo Sik Choi, Shigeki Toyama2011 Volume 48 Issue 9 Pages 652-655
Published: September 10, 2011
Released on J-STAGE: January 26, 2016
JOURNAL RESTRICTED ACCESSPresident Park Jeong-hui had promoted "The Saemaul Movement" in early 1970s to improve people's life, and straw-thatched roofs in agricultural villages were displaced by asbestos containing slates, which have resulted in scattering hazardous materials. The Korean government has determined to enact the asbestos safety law from 2012 and established Korea Research Center of Asbestos-Related Diseases in Pusan National University in advance. The paper reviews and proposes detoxification and recycling of waste asbestos-containing building materials based on technical state of Korea and Japan, where development of an on-site transferable plant is suggested to be effective.View full abstractDownload PDF (538K)
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