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YOSHIYUKI YOKOGAWA, HARI KRISHNA VARMA, KAORI NISHIZAWA, FUKUE NAGATA, ...
1999 Volume 9 Pages
1-4
Published: 1999
Released on J-STAGE: October 29, 2012
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Calcium phosphate growth on surface functionalized cellulose, or chitin was studied. Cellulose or chitin fibers phosphorylated (then soaked in saturated Ca(OH)
2 solution at ambient temperature) or treated with silane coupling reagent were found to stimulate the growth of a calcium phosphate coating on their surfaces after soaking in 1.5xSBF solution at 36.5°C as little as one day. Surface functionalization such as phosphorylation or treatment of silane coupling reagent has been found to be a useful method for making the fiber surface susceptible to biomimetic deposition of calcium phosphate coating.
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TAKASHI HANAZAWA, MAMORU AIZAWA, F. SCOTT HOWELL, KIYOSHI ITATANI
1999 Volume 9 Pages
5-10
Published: 1999
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Magnesium-substituted hydroxyapatite (Mg-HAp) powders with the formula of Ca
10-xMg
x(PO
4)
6(OH)
2, where x=0, 0.25, 0.5, 0.75, 1, 1.5, 2, 5 and 10, were prepared by spray-pyrolyzing the aqueous solutions in the Ca(NO
3)
2-Mg(NO
3)
2-(NH
4)
2HPO
4-HNO
3 system. Although only the hydroxyapatite (HAp) was present in the case of x=0, β-tricalcium phosphate (β-TCP) formed with increasing x value. Only β-TCP was present in the case of x=1.5; however, it was gradually changed into the amorphous phase with a further increase in x value. The data on lattice constants of the HAp and/or β-TCP in the range of x=0 to 1 showed that the Mg
2+ ions could be substituted with the Ca
2+ ions in HAp; the maximum substituted amount was estimated to be ~7.7 mol%.
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Koji IOKU, Yasuhiro EGUCHI, Hirotaka FUJIMORI, Seishi GOTO, Wojciech S ...
1999 Volume 9 Pages
11-16
Published: 1999
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Porous materials of calcium hydroxyapatite (CaHA) and strontium hydroxyapatite (SrHA) were prepared by hydrothermal technique from amorphous calcium phosphate and amorphous strontium phosphate, respectively. The amorphous Ca- and Sr- phosphate powders were compacted and subsequently hydrothermally treated in ammonia solution at temperatures fro 105°C to 250°C for 20h under saturated vapor pressure. The prepared porous materials consisted of rod-shaped crystals of 3-10 μm in length and with the aspect ratio in the range of 15-50. They had a porosity of about 60% with an interconnecting pore structure and compressive strength of 20-25 MPa. Both CaHA and SrHA materials were homogeneous and nonstoichiometric with Ca(Sr)/P molar ratios in the range of 1.50-1.60. The microstructure and chemical composition of the porous CaHA and SrHA materials could easily be controlled by changing the preparation conditions.
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MASAMI NANZYO, YASUO NAKAMARU, SHIN-ICHI YAMASAKI
1999 Volume 9 Pages
17-22
Published: 1999
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The amount of apatite dissolution increased with decreasing final pH when two apatite samples (0.2-0.04mm) were treated with 10mmol L
-1 of citric acid or 4-0mmol L
-1 HCl. However, when they were treated with 10mmol L
-1 of oxalic acid, the amount of dissolution was much smaller than the treatment with the same concentration of citric acid at around pH 4. According to the X-ray diffraction (XRD), scanning electron microscope (SEM) observation and energy dispersive X-ray analysis (EDX) of the oxalic acid-treated apatite, a coating of calcium oxalate was formed on the surface of the apatite particles which inhibited the dissolution of apatite under the experimental conditions.
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S. SHIMABAYASHI, K. KISHIMOTO, T. HINO
1999 Volume 9 Pages
23-30
Published: 1999
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The adsorption amount of bovine serum albumin(BSA) on hydroxyapatite(HAP) decreased with concentrations of an added sodium chondroitin-6-sulfate(Chs) and a phosphate buffer when the solution pH was higher than an isoelectric point(i. e. p., pH4.9) of BSA. That of Chs also decreased in the presence of BSA due to their mutual competition for the adsorption sites. On the other hand, at a pH lower than the i. e. p., which was prepared by means of a glycine buffer, their adsorption amounts increased in the presence of the other owing to electrostatic attractive force between them, resulting in formation of the surface complex of BSA with Chs. These results were discussed, taking a zeta potential of HAP into consideration.
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ZAHID AMJAD
1999 Volume 9 Pages
31-40
Published: 1999
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This paper addresses the precipitation of calcium phosphate from aqueous solution at pH 8.50 and 50°C. The aim of the study was to investigate the role of cationic polymer (CP) on the performance of several anionic calcium phosphate inhibiting polymers.The anionic polymers studied include poly (acrylic acid), P-AA; poly (maleic acid), P-MA; poly (acrylic acid: 2-acrylamido-2-methylpropane sulfonic acid: sulfonated styrene), P-AA:SA:SS; poly (maleic acid:sulfonated styrene), P-MA:SS; and poly (acrylic acid: 2-acrylamido-2-methylpropane sulfonic acid), P-AA:SA. It has been found that addition of low concentration (from 0.5 to 1.5 ppm) of cationic polymer has a marked antagonistic effect on the performance of polymers in terms of inhibiting calcium phosphate precipitation. The inhibition data of several polymers indicate that the performance of the polymers depends upon the functional group. The overall ranking of polymers in terms of CP tolerance is: P-AA:SA:SS>P-AA:SA>P-MA:SS>> PAA~PMA.
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ZAHID AMJAD
1999 Volume 9 Pages
41-48
Published: 1999
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The effect of polyelectrolytes such as fulvic acid,tannic acid, poly (acrylic acid), and acrylic acid-based copolymers containing different functional groups on the precipitation of amorphous calcium phosphate (ACP) at pH 7.40, 37°C was studied using the pH-stat method. Of the natural polyelectrolytes investigated, fulvic acid at low concentrations effectively delayed the precipitation of ACP. The results on the influence of synthetic polyelectrolytes as inhibitors for ACP show that polyelectrolyte effectiveness as inhibitor strongly depends upon the type and number of monomers present in the polyelectrolyte. Based on the inhibition data the ranking in terms of decreasing effectiveness of the polyelectrolytes tested is: terpolymer>copolymer>homopolymer>fulvic acid>tannic acid.
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MICHIHIRO MIYAKE, MASATOSHI YOSHINO, MOTOHIDE MATSUDA, MASASHI KIGUCHI ...
1999 Volume 9 Pages
49-54
Published: 1999
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Nitroaniline isomers (o-, m-, and p-NA) were loaded in the one-dimensional channels of AlPO
4-5 by vapor-phase diffusion process, and the resulting materials (o-NA/AlPO
4-5, m-NA/AlPO
4-5, and p-NA/AlPO
4-5) were characterized. The maximum loadings for o-, m-, and p-NA were estimated to be about 1.8, 1.3, and 1.5 molecules per unit cell, respectively. The resulting materials exhibited nonlinear optical properties, and the order of the properties was found to be m-NA/AlPO
4-5<o-NA/AlPO
4-5 <<p-NA/AlPO
4-5 at maximum loadings.
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HIROKAZU NAKAYAMA, MAYUMI DANJO, MITSUTOMO TSUHAKO, TARO EGUCHI, NOBUO ...
1999 Volume 9 Pages
55-62
Published: 1999
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n-Alkylamine intercalation compounds of γ-Ce(H
2PO
4)(PO
4)·1.33H
2O were synthesized and were investigated by XRD, and
31P,
13C solid-state NMR. n-Alkylamine in the intercalation compounds forms a bilayer of alkyl chains in a trans-trans conformation and the terminal protonated amino group, -NH
3+, was dipped into the cavity of PO
4 site.
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NORIYASU OKAZAKI, MOTOI TAKAHASHI, HIROYUKI MURAI, AKIO TADA
1999 Volume 9 Pages
63-68
Published: 1999
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BPO
4 was characterized by XRD, IR, and XPS. It was found that XPS technique serves as a powerful tool for detecting the presence of small amount of residual H
3BO
3 or B
2O
3 in a BPO
4 sample. The XPS B1s spectrum of the BPO
4 sample was deconvoluted into two peaks; one with higher binding energy was assigned to H
3BO
3 or B
2O
3, and the other with lower binding energy was assigned to BPO
4.
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HIROAKI ONODA, HIROYUKI NARIAI, HIDESHI MAKI, ITARU MOTOOKA
1999 Volume 9 Pages
69-74
Published: 1999
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Rare-earth ultraphosphates, RP
5O
14, were synthesized, and their mechanochemical effects due to grinding were investigated by using TG-DTA, XRD, FT-IR and SEM. When the ultraphosphates were ground, their XRD peaks became smaller, their particles were flocculated to be paste, and their P-O-P bondings were cleaved to form P-O-H bondings. The P-O-H bondings formed by mechanical treatment were expected to raise catalytic activities of rare-earth ultraphosphates. The ultraphosphates reformed by grinding enlarged the surface areas, the acid strength, amount of acidic sites, and the conversion of 2-propanol to propylene.
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YUZO IMIZU, NAOKI MATSUDA, HIDENOBU ITOH, AKIO TADA
1999 Volume 9 Pages
75-79
Published: 1999
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The isomerization of methylcyclopropane on several metal phosphates including AlPO
4, Zr(HPO
4)
2, Ti(HPO
4)
2, Ca
3(PO
4)
2, and Ni
3(PO
4)
2 was examined. Only n-butenes were formed as products; neither cyclobutane nor isobutene was detected. The composition of n-butenes was essentially independent of the extent of conversion but altered depending on the kind of phosphates. On the basis of product distributions, proton addition mechanism (Brønsted site) is presented for the isomerization of methylcyclopropane.
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NORIYASU OKAZAKI, FUMIO ISHIDA, YUKITO UCHIMURA, YUZO IMIZU, AKIO TADA
1999 Volume 9 Pages
81-86
Published: 1999
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Cobalt phosphate showed catalytic activity for the title reaction, only when it was treated with hydrogen. The activity depended on its hydrogen-treatment temperature and reached a maximum at 550°C. The hydrogenation of 1, 3-butadiene over hydrogen-treated cobalt phosphate produced selectively butene with a preferential percentage of 1-butene even at a high temperature.
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YOH SASAKI, TAKUYA NOMOTO, SHUNRO YAMAGUCHI, JUNKO ICHIHARA
1999 Volume 9 Pages
87-90
Published: 1999
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Catalytic activities of cetylpyridinium heteropoly peroxide and isopoly peroxide for epoxidation of allyl alcohols were examined in biphasic system (aq. H
2O
2-organic solvent). Heteropoly peroxide [PW
4O
8(O
2)
8]
3- (PW4) possesses partial structure of isopoly peroxide [W
2O
3(O
2)
4]
2- (W
2O
11), however, the reactivities for epoxidation are significantly different.
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MAKOTO WATANABE, YOSHINORI YAMAGUCHI, MAKOTO SAKURAI, HIROKAZU SUZUKI, ...
1999 Volume 9 Pages
91-96
Published: 1999
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Preparation of ammonium polyphosphate form II was achieved by the phase transition of ammonium polyphosphate form I under alternate flow of wet ammonia and dry air at 270 to 310°C. The alternate gas-flow started with wet ammonia gave a better result than that started with dry air. When a wet ammonia gas prepared by passing air through 3 to 5% ammonia water was used, the phase transition from form I to II of ammonium polyphosphate was done with a transition ratio higher than 95% at a lower reaction temperature and a shorter reaction time than under other wet ammonia.
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MAKOTO WATANABE, YOSHINORI YAMAGUCHI, MAKOTO SAKURAI, HIROKAZU SUZUKI, ...
1999 Volume 9 Pages
97-102
Published: 1999
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In the preparation of ammonium polyphosphate form II according to the phase transition of ammonium polyphosphate form I under alternate flow of wet ammonia and dry air, particle size of ammonium polyphosphate form II was controlled by changing flow time of alternate flow-gases of wet ammonia and dry air. To obtain a small crystalof ammonium polyphosphate form II, the phase transition from form I to II on ammonium polyphosphate under a short flow time of wet ammonia was required. Under the reaction conditions, APP form-II crystals with average particle sizes smaller than 2.6μm were produced and the APP crystals with particle sizes larger than 4μm were not included in the products.
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MAKOTO SAKURAI, MAKOTO YASUI, HIROKAZU SUZUKI, MIOKO MAEDA, MAKOTO WAT ...
1999 Volume 9 Pages
103-106
Published: 1999
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Triammonium cyclo-tri-μ-imido-triphosphate monohydrate has been prepared by adding ethanol into a mixture of cyclo-tri-μ-imido-triphosphoric acid and ammonia water. When the triammonium cyclo-tri-μ-imido-triphosphate was heated, release of the water of crystallization was observed and no decomposition of the imidophosphate occurred up to 145°C. The imidophosphate decomposed to produce many kinds of condensed phosphates with or without NH and NH
2 groups at a temperature higher than 145°C. The sample finally changed to phosphoric acid and oligophosphates including amino and imino groups.
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ATSUSHI TAKENAKA, YUKIO TSUNODA, HIROYUKI SAWA
1999 Volume 9 Pages
107-110
Published: 1999
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Thermal reaction of copper (II) oxide-ammonium dihydrogenphosphate-urea mixtures was carried out in a stream of nitrogen gas to prepare cyclo-tetraphosphate. Addition of urea was not effective for the formation of cyclo-tetraphosphate. Instead, an appreciable amount of cyclo-octaphosphate was produced at 400°C and at the urea/CuO/NH
4H
2PO
4 mixing molar ratio of 2/1/2 or 4/1/2. Sodium cyclo-octaphosphate heptahydrate, Na
8P
8O
24·7H
2O, was prepared from the thermal product of a mixture with the urea/CuO/NH
4H
2PO
4 molar ratio of 2/1/2.
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ATSUSHI TAKENAKA, SHINYA YOSHIDA
1999 Volume 9 Pages
111-114
Published: 1999
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In order to prepare cyclo-octaphosphate, lead (II) oxide-ammonium dihydrogenphosphate-urea mixtures were heated in a stream of nitrogen gas. Addition of an appropriate amount of urea was effective for the formation of cyclo-octaphosphate. The maximum percentage of phosphorus atoms present as cyclo-octaphosphate was ca. 36P% at 350°C and at the urea/PbO/NH
4H
2PO
4 mixing molar ratio of 2/1/2.
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