K. Udoh
Kyushu University
FabricationTransmission electron microscopyMonolithComposite materialChemistryHardening (metallurgy)MetallurgyMaterials scienceMineralogyPhosphateSinteringApatiteCalcium carbonateCalcium hydroxidePolyurethaneAlloyCalciteCarbonate apatiteCompressive strengthChemical engineeringPhase (matter)CrystallinityCalciumPorosityElectron diffractionCrystallographyPhase diagramMicrostructure
26Publications
7H-index
249Citations
Publications 25
Newest
#1K. Udoh (Kyushu University)H-Index: 7
#2Melvin L. Munar (Kyushu University)H-Index: 11
Last. Kunio Ishikawa (Kyushu University)H-Index: 53
view all 5 authors...
Effects of sintering temperature on the physical and compositional properties of α-TCP foam fabricated using the polyurethane foam method were examined. When a polyurethane foam coated with α-TCP slurry was sintered at 1,400–1,550°C, α-TCP foam having basically the same fully interconnected porous structure was produced although shrinkage occurred with increasing sintering temperature. On porosity of the α-TCP foam, a higher foam porosity of 95% was obtained when sintered at 1,400°C as compared ...
19 CitationsSource
#1Kunihiro Hisatsune (Nagasaki University)H-Index: 10
#2K. Udoh (Yamaguchi University)H-Index: 7
Last. Takeshi Fujita (Nagasaki University)H-Index: 3
view all 6 authors...
The effects of indium addition to CuAu on the alloy phase transformation behavior were investigated by hardness tests, electrical resistivity measurements, X-ray diffraction and transmission electron microscopy. These established that indium additions lower the critical temperature and stabilize the CuAu II phase at room temperature. Formation of the long period ordered phase produces an age-hardening; although this age-hardening is retarded, the degree of hardening is comparable to that in CuAu...
2 CitationsSource
#1Satoshi Karashima (Kyushu University)H-Index: 2
#2Akari Takeuchi (Kyushu University)H-Index: 11
Last. Kunio Ishikawa (Kyushu University)H-Index: 53
view all 6 authors...
Low-crystallinity hydroxyapatite (HAP) foam is an ideal material for bone substitutes and scaffolds for bone tissue regeneration, because its interconnected pores provide the space for cell growth and tissue penetration, and its composition induces excellent tissue response and good osteoconductivity. In this study, the feasibility of low-crystallinity HAP foam fabrication was evaluated based on the phase transformation reaction or the so-called dissolution-reprecipitation reaction of α-tricalci...
29 CitationsSource
#1Hanae Wakae (Kyushu University)H-Index: 3
#2Akari Takeuchi (Kyushu University)H-Index: 11
Last. Kunio Ishikawa (Kyushu University)H-Index: 53
view all 8 authors...
Bone consists of a mineral phase (carbonate apatite) and an organic phase (principally collagen). Cancellous bone is characterized by interconnecting porosity necessary for tissue ingrowth and nourishment of bone cells. The purpose of the present study was to fabricate macroporous carbonate apatite (CAP) blocks with interconnecting porosity as potential bone substitute biomaterials by hydrothermal conversion of α-TCP foam in carbonate solution. The fabrication of the macroporous CAP was accompli...
72 CitationsSource
#1Hanae Wakae (Kyushu University)H-Index: 3
#2Akari Takeuchi (Kyushu University)H-Index: 11
Last. Ishikawa Kunio (Kyushu University)H-Index: 5
view all 8 authors...
We have previously reported that the carbonate apatite (CAP) foam that has similarities in both inorganic chemical composition and morphology to cancellous bone could be prepared from α-tricalcium phosphate (α-TCP) foam by the hydrothermal treatment with Na2CO3 at 200°C for 24 hrs. However, the crystallinity of the CAP foam was much higher than that of bone. In order to prepare CAP foam similar to cancellous bone in crystallinity as well as its inorganic composition and morphology, this study at...
2 CitationsSource
#1Shigeki Matsuya (Fukuoka Dental College)H-Index: 27
#2Xin Lin (Kyushu University)H-Index: 4
Last. Kunio Ishikawa (Kyushu University)H-Index: 53
view all 7 authors...
Calcium carbonate (CaCO3) has been widely used as a bone substitute material because of its excellent tissue response and good resorbability. In this experimental study, we propose a new method obtaining porous CaCO3 monolith for an artificial bone substitute. In the method, calcium hydroxide compacts were exposed to carbon dioxide saturated with water vapor at room temperature. Carbonation completed within 3 days and calcite was the only product. The mechanical strength of CaCO3 monolith increa...
24 CitationsSource
#1Melvin L. Munar (Kyushu University)H-Index: 11
#2K. Udoh (Kyushu University)H-Index: 7
Last. Masaharu Nakagawa (Kyushu University)H-Index: 17
view all 5 authors...
: Porous hydroxyapatite (HAP) foam permits three-dimensional (3D) structure with fully interconnecting pores as well as excellent tissue response and good osteoconductivity. It is therefore thought to be a good candidate as scaffold material for bone regeneration and as a synthetic bone substitute material. To fabricate better porous HAP foam, improved physical and structural properties as well as higher osteoconductivity are desired. In the present study, the effects of sintering temperature on...
68 CitationsSource
#1Shigeki Matsuya (Kyushu University)H-Index: 27
#2K. Udoh (Yamaguchi University)H-Index: 7
Last. Kunio IshikawaH-Index: 53
view all 4 authors...
Source
#1Yumiko Suzuki (Kyushu University)H-Index: 5
#2Shigeki Matsuya (Kyushu University)H-Index: 27
Last. Kunio Ishikawa (Kyushu University)H-Index: 53
view all 7 authors...
The aim of this study was to evaluate the feasibility of fabricating low-crystalline, porous apatite block using set gypsum as a precursor based on the fact that apatite is thermodynamically more stable than gypsum. When the set gypsum was immersed in 1mol/L diammonium hydrogen phosphate aqueous solution at 100°C, it transformed to low-crystalline porous apatite retaining its original shape. The transformation reaction caused a release of sulfate ions due to an ion exchange with phosphate ions, ...
23 CitationsSource
#1Rhodora H. Luciano (University of the East)H-Index: 2
#2Takanobu Shiraishi (Nagasaki University)H-Index: 13
Last. Kunihiro Hisatsune (Nagasaki University)H-Index: 14
view all 5 authors...
Abstract A coherent phase diagram for the pseudobinary system (AuCu) 1− x Pd x with x ≤ 0.10 was constructed based on phase identification and microstructural analysis by transmission electron microscopy. It was confirmed that the addition of palladium exceeding 1.0 at.% to the equiatomic AuCu eliminated the AuCu II long-period superstructure from the phase equilibria and stabilized the AuCu I superstructure. The AuCu–0.5 at.% Pd and AuCu–1.0 at.% Pd alloys isothermally aged for long time at tem...
3 CitationsSource