bluuebunny/crossref_metadata_2025 huggingface dataset:
The Evaluation of Cytotoxicity and Histological Response of Periradicular Tissues of a New Injectable Root Canal Sealer
Authors: Teng Li Zhao , Fan Hong Song , Zhang Xing Dong
Published: March 2009

The purpose of this study was to evaluate biocompatibility of a new injectable root
canal sealer. The cytotoxicity of zinc oxide-eugenol cements, CCQ and the new injectable root
canal sealer were assessed by the MTT assays. These materials were filled into the root canals of
the dog. One month later, the dog was sacrificed and the X-ray photos were taken. The histological
response was observed through the microscope. The results show the new injectable root canal
sealer showed better biocompatibility than the other two materials.
Comparative Analysis on the Precision Fit of Dental Prosthesis between the Variously Fabricated Copings of Nickel-Chromium Alloy, Titanium and Zirconia Ceramic
Authors: Lee S.W. , Kim J.W. , Hwang S.H. , Han Dong Hoo , Moon H.S.
Published: March 2009

Precision fit of dental prostheses were compared between the four experimental groups of
cast Ni-Cr alloy, cast titanium, milled titanium and milled zirconium by measuring and comparing
the mean values of the marginal, axial, occlusal and overall coping-die gaps. The overall, axial and
occlusal fit was most precise with the cast Ni-Cr alloy prosthesis. The biologically critical marginal
fit was the most precise with the milled zirconium, thus suggesting that the copy-milled zirconia
ceramic could serve as an alternative to the cast-metal prosthesis. The statistical variables, such as
the groups and the regions, were in association with and had an interaction effect on the adaptability
of the prostheses. The marginal gaps correlated with the axial gaps in the cast Ni-Cr alloy and
milled titanium groups
Base-Coated Zirconia Brackets for Orthodontics
Authors: Lee Myung Hyun , Oh K.S. , Kim Y.K. , Lim H.B. , Lee Deuk Yong , Oh Nam Sik
Published: March 2009

Yttria and iron co-doped tetragonal zirconia polycrystals ((Y, Fe)-TZPs) were investigated
to evaluate the feasibility for the ceramic bracket application. Presintered the (Y,Fe)-TZPs brackets
were machined, abraded and coated with granule spray containing 10~50 wt% of flux. Finally, the
base-coated brackets were sintered. Roughness of the coated surface was decreased to 13 um and 10
um when the flux content was 30 wt% and 50 wt%, respectively. It may be due to the fusion and the
collapse of the granules as a result of the high amount of flux. Better adhesion to the base surface of
the brackets and irregular shape were observed by raising the amount of flux in the slurries. Wetting
angle of ethylene glycol droplet on the (Y,Fe)-TZP bare surface was determined to be 41.85°,
however, the angle became 0° after the granule spraying treatments. The (Y,Fe)-TZP brackets
exhibited uniform embossed base and good wetting. The newly developed base-coated bracket could
be highly applicable to enhance retention and to reduce adhesive resin remnant during the bracket
debonding.
Fabrication and Characterization of Bioactive Glass Reinforced CaSiO3 Ceramics
Authors: Lin Kai Li , Ni Si Yu , Chang Jiang , Zhai Wan Yin , Gu Wei Ming
Published: March 2009

fabricated by pressureless sintering process. The effect of BG on the sintering ability and
mechanical strength of the ceramics, and the adhesion and proliferation of osteoblasts were
investigated. The results showed that the optimum amount of BG was 20wt.% and the samples
sintered at 1100oC for 5h revealed a bending strength of 172 MPa, which was approximately
2-times higher than that of the pure CaSiO3 ceramics. The cell experiments showed that BG
reinforced CaSiO3 ceramics supported osteoblast adhesion and possessed higher proliferation than
that of the pure CaSiO3 ceramics, which indicated excellent biocompatibility. Our results suggested
that BG reinforced CaSiO3 ceramics could be potential candidates as bioactive bone implant
materials.
Sintering Effect on Mechanical Properties of Composites Made of Bovine Hydroxyapatite (BHA) and Commercial Inert Glass (CIG)
Authors: Salman S. , Oktar Faik N. , Gunduz Oguzhan , Agathopoulos Simeon , Öveçoğlu M. Lutfy , Kayali E.S.
Published: March 2009

Composite biomaterials of calcinated bovine bone derived hydroxyapatite (HA) doped
with 5 and 10 wt% commercial inert glass (CIG) were prepared by sintering. The production of HA
from natural sources satisfies economic and time-saving aims, while the use of CIGs is directed by
economic and ecological aspects. The produced composites were subjected to scanning electron
microscopy (SEM) and X-ray diffraction analysis. Measurements of compression strength,
microhardness, and density were also carried out. The experimental results and their discussion
showed that the type and the composition of incorporated glass are of crucial importance.
Consequently, provided that an optimum amount of glass is incorporated, the resultant materials can
exhibit good values of compression strength and microhardness and hence they can be suggested for
potential use in load-bearing biomedical applications.
The Influence of Bioactive Glass Particles on Osteolysis
Authors: Kim Duck Hyun , Lee Kang Sik , Kim Jung Hwa , Chang Jae Suk , Kim Yung Tae
Published: March 2009

We observed the cytotoxicity of human bone marrow stromal cells(hBMSCs) by microparticles
of bioactive glass with four particle groups(same chemical composition-45S5 but
produced by two different manufacturer and two different size groups). In vivo test using rat
calvaria were also carried out. The apoptosis rates of all small particle groups(10-20 ㎛) were
increased than large(500-700 ㎛ or 200-900 ㎛) particle groups in any culture time and any amount
of particles with statistical significance. In vivo study we observed pathologic signs such as
macrophages and foreign-body giant cells in rat calvaria by micro-particles of bioglass. Small(10-
20 ㎛) sized particles induced foreign body reaction and bone resorption. There was proliferation of
macrophages and cells in large number. But in large particle groups, only fibroblasts were
surrounding the particles. The micro-particles of bioglass induced apoptosis of hBMSC and foreign
body reaction in calvaria of rat, therefore micro-particles of bioglass may cause osteolysis if used in
replacement arthroplasty.
Effect of Inorganic Ions on Gelation, Particle Morphology, and Texture of Solo-Gel-Derived Silica Nanospheres
Authors: Gou Zhong Ru , Weng Wen Jian , Zou Chao , Du Pi Yi , Han Gao Rong
Published: March 2009

The gelation process is of importance for the structure and texture of the silica particle and further functionalization in the area of biomedical application. In a base-catalysis process the sodium phosphate or plus calcium nitrate salts could be added to induce the gelling velocity and particle size distribution. Multivalent anions (phosphate ions) or dication (calcium ions) induce the microscopic phase separation and accelerate gelation of silica sol. Furthermore, the composite silica nanospheres show excellent monodispersibility as well as pH-stability in the simulated body fluids or Tris-HCl buffer solution, which will help to surface modification and functionalization in the biomolecule-existing environments.
Synthesis and Characterization of Yttrium/Hydroxyapatite Nanoparticles
Authors: Liu Yi , Zhou Rong Jin , Mo An Chun , Chen Zhi Qing , Wu Hong Kun
Published: March 2009

The aim of this study was to synthesize yttrium/hydroxyapatite(Y/HA) nanoparticles and submit to a structural, chemical and biological characterization. The microstructure, shape and size, concentration of yttrium released in water were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and Inductively coupled plasma (ICP). The biological actions were evaluated by the cell cultivation method and oral bacterial colony counting method. The results showed that yttrium can be incorporated into the hydroxyapatite structure. Sizes of the nanocrystals were less than 100nm. The shape was needle-like. The human periodontal fibroblast growth was accelerated and oral bacterial growth was lightly restricted. The data indicate that the hydrothermally synthetized approach can be successfully used to prepare yttrium/hydroxyapatite nanocrystals with crystallinity, crystal dimensions, structure and stability close to those characteristic of biological apatite and with better biological activity, bacteriostasis.
Antibacterial Activity of Silver-Hydroxyapatite/Titania Nanoparticles on Oral Bacteria
Authors: Liao Juan , Mo An Chun , Wu Hong Kun , Zhang Jing Chao , Li Yu Bao , Lv Guo Yu
Published: March 2009

Since bacterial accumulation surrounding biomaterials has pathogens known to cause the
biomaterials centered infection, it may be important to develop some kind of biomaterial with
antibacterial activity as well as biocompatibility. This study focused on evaluating the antibacterial
activity of silver-hydroxyapatite/ Titania nanoparticles (Ag-nHA/nTiO2) against oral bacteria with
agar dilution method. Bacteria were seeded on agar plate containing antibacterial material with
different concentrations after incubation of 48 hours. The antibacterial activity was demonstrated by
MICs. The MICs of Ag-nHA/nTiO2 ranged between 1000μg/ ml and 7500μg /ml under anaerobic
conditions. And it also exhibited remarkable antibacterial activity to all the aerobe bacteria
(MIC≤500μg/ml). On the other hand, the antibacterial activities of Ag-nHA/nTiO2 differentiate to
some extent with the bacterial strains. This Ag-nHA/nTiO2 exhibited remarkable antibacterial
activity to anaerobic and aerobe bacteria. This antibacterial effect may reduce the potential for
bacterial colonisation of oral biomaterials with Ag-nHA/nTiO2.
Ce(IV) Doped TiO2 Nanoparticles and the Effect on Proliferation of BEL7402 Human Hepatoma Cells
Authors: Wang L. , Mao J. , Zhang X.L. , Tu M.J. , Kan B. , Wei Y.Q.
Published: March 2009

To investigate nanoparticles’ antitumor effect, a globose 30~35nm Ce(IV) doped Titanium dioxide nanoparticles (CDT) were prepared by impregnation method and characterized by X-ray diffraction (XRD) and transmission electron microscopy(TEM). Proliferation of BEL7402 human Hepatoma cells was studied in vitro by using fluorescence microscopy and Flow Cytometry. The results show that cerium elements doping enhanced thermal stability of nano-size titanium dioxide to 800°C. With UV irradiated for 8min, BEL7402 were induced a dose-dependent apoptosis by CDT, about 28.2% , 41.5% and 88.3% cells were induced apoptosis after 24h at concentration of 60, 120 and 180ug/ml respectively, relative to 3.9% of that of control group cell just only in the presence of UV.
Preparation and Cytocompatibility of Novel Nano-HA/PLA Composite
Authors: Xiao Wen Qian , Xiao Yu Mei , Wen Xian Tao , Fan Hong Song , Zhang Xing Dong
Published: March 2009

In order to prepare nano-hydroxyapatite/poly(lactide) (n-HA/PLA) composite with good
interfacial interaction, some groups which could bind with Ca ions in HA crystals need to be
introduced onto PLA surface. Poly(α-methacrylic acid) (PMAA) was grafted on the PLA surfaces
via photooxidization and subsequent UV induced polymerization. Suspension of PMAA-PLA
microparticles with an average size as 133.1nm was prepared with solvent evaporation technique.
Then utilizing the action of template manipulating of PMAA-PLA microparticles, n-HA/PLA
composite were synthesized. Zeta potentials measurement and SEM indicated that there were good
interfacial interactions between two phases of n-HA/PLA composite. The results of cell viability
confirmed that n-HA/PLA composite possessed good cytocompatibility, so the n-HA/PLA
composite scaffold obtained by electrospun technology might be used as bone tissue engineering
scaffold.
Improvement of the Adhesion and Proliferation of Human Osteoblastic-Like Cells with Biomimetic Nanoapatite Coatings
Authors: Pan Zhi Jun , Guan Bing Gang , Yang Di Sheng , Feng Jie , Yan Wei Qi
Published: March 2009

Biomimetic nanoapatite coatings was developed by functionally modified methods with a
combination of topographic, chemical and biomimetic treatments on the surface of titanium (Ti)
substrate. The biological behavior and bioactivity of functionally modified SLA implants with
chemical and biomimetic treatments (SCB-treated Ti) using body like solution were investigated to
compare with untreated Ti and SLA Ti plates as controls. The cell attachment, proliferation,
alkaline phosphotatse (AKP) activity, cell morphology and differentiation were evaluated by using
MTT, RT-PCR, scanning electron microscopy (SEM) and confocal laser-scanning microscope
(CLSM) analysis system. The results showed that the cell adhesion and proliferation was enhanced
on functionalized titanium surface with nano-scale apatite compared to the controls. SEM
micrographs also revealed that the osteoblast-like cells spreadly grew along the surface. Cell
morphology and differentiation could be further observed distinctly by CLSM graphs. Moreover,
mRNA expression of alkaline phosphotatse in nucleus on the SCB-treated Ti increased obviously
on the third day compared with the controls. The in vitro results demonstrated the remarkable
improvement on cell adhesion and proliferation of the biomimetic nanoapatite on SCB-treated Ti,
which could be used for orthopaedic/dental implants.
Physical and Adhesive Properties of Cyanoacrylate-Based β-TCP Composites
Authors: Lee G.S. , Lee Sang Bae , Lee Doug Youn , Park Kyeong Jun , Kim S.O. , Kim Kyoung Nam , Choi B.J.
Published: March 2009

Histoacryl® (N-butyl-2-cyanoacrylate) has been widely utilized as a tissue adhesive. The aim of this study was to evaluate the physical and adhesive properties of newly developed cyanoacrylate-based β-TCP composite systems. The β-TCP powder was modified on the surface with citric acid to make this material mixed with cyanoacrylate easily. The setting time of acidtreated β-TCP/ Histoacryl® systems was dramatically prolonged and the polymerization heat was significantly decreased compared to that of untreated β-TCP/Histoacryl® system. The shear bond strength of cyanoacrylate-based β-TCP composites decreased with addition of acid-treated β-TCP filler. The compressive strength of β-TCP/Histoacryl® composites increased strongly with increasing the amount of acid-treated β-TCP filler. The cytotoxicity of the β-TCP/Histoacryl® composites decreased with the increasing of the amount of added β-TCP. These results indicated that our novel β-TCP/Histoacryl® composites had the great potential to serve as adhesives or filling materials in the dental field.
Grafting Collagen on the Plasma Sprayed Titania Coating Treated by Sodium Hydroxide
Authors: Li Baoe , Liu Xuan Yong , Ding Chuan Xian
Published: March 2009

In this work, collagen type I was covalently grafted on the surface of plasma sprayed
titania coatings to improve their biocompatibility. The plasma sprayed titania coatings were
pretreated by sodium hydroxide to induce the formation of hydroxyl groups which can covalently
graft collagen, rendering the collagen having good stability. The dependence of collagen grafting on
the sodium hydroxide treatment conditions (concentration, time and temperature) was investigated
by measuring the amount of collagen grafted on the titania surface. The biocompatibility of the
titania coatings with grafted collagen was evaluated by in vitro cell culture. The results showed that
the amount of collagen grafted on the titania coatings increased with the concentration of the
sodium hydroxide and the treating temperature, while that on the coating is slightly dependent on
the treatment time in sodium hydroxide. In vitro cell culture test proved the positive effects of
collagen on the biocompatibility of the plasma sprayed titania coating.
pDNA and Calcium Phosphate Co-Precipitation on Titanium Alloy Plate
Authors: Yang Liang , van Blitterswijk Clemens A. , Barrere F.
Published: March 2009

DNA transfection by biomaterial is a promising strategy to stimulate cells in tissue
engineering. Co-precipitation of Calcium Phosphate (CaP) with plasmid DNA (pDNA) is known
for several decades as non-viral transfection agent [1]. In this study, we report the co-precipitation
of different pDNA into biomimetic calcium phosphate coating onto titanium alloy (Ti) plates in
order to evaluate their efficiency of incorporation. And it is possible to tune the rate of coprecipitation
by changing the volume of Calcium Phosphate Solution (CPS) and the [pDNA]. The
structure of coating was affected by the presence of DNA in CPS solution.
Apatite-Forming Ability of Pectin Gels in Simulated Body Environment
Authors: Ichibouji Takashi , Miyazaki Toshiki , Ishida Eiichi , Ashizuka Masahiro , Sugino Atsushi , Ohtsuki Chikara , Kuramoto Koichi
Published: March 2009

Apatite-polymer hybrids are expected as novel bone substitutes exhibiting bone-bonding
ability and mechanical performances analogous to those of natural bone. In this study, we attempted
preparation of organic-inorganic hybrids from different pectins such as pectic acid, apple-derived
pectin and citrus-derived pectin through apatite deposition in simulated body fluid (SBF). Pectin gels
were prepared by CaCl2 treatment of aqueous solutions of pectin. Apatite-forming ability of the gels
was examined in SBF. The citrus-derived pectin showed tendency to form the largest amount of the
apatite in SBF.
Growth of Calcium Phosphate on Poled Piezoelectric Poly-L-lactic Acid Membrane by a Biomimetic Method
Authors: Huang Chun Peng , Guan Dong Hua , Tian Kun , Chen Xin Min , Niu Lin , Wang Peng , Qu Yi Li , Ye Yong Mei , Chen Zhi Qing
Published: March 2009

The bioactivity of poled piezoelectric PLLA membrane was investigated by studying the
calcium phosphate formation in vitro using a biomimetic method. Samples (φ10mm) were poled
under DC electric field of 8~l0kV/cm at 70°C for 30 min followed by cooling under the electric field.
Surface chemistry of the samples before and after poling treatment was studied by X-ray
photoelectron spectroscopy (XPS). Poled/unpoled samples were immersed in supersaturated
calcification solution (SCS) for periods up to 24 h (36.5°C). The surface morphology and composition
of the soaked samples were evaluated by using scanning electron microscope (SEM) and X-ray
diffraction analysis (XRD). Poled samples showed two different charged surfaces, negatively-charged
surface (N-PLLA) and positively-charged surface (P-PLLA). On the N-PLLA surfaces, SEM together
with XRD showed a gradually formed calcium phosphate (Ca-P), while no obvious Ca-P on either
P-PLLA or unpoled samples was observed. This study demonstrated that poled piezoelectric PLLA
substrates induce substantially higher level of Ca-P formation than electrically neutral substrates and
only N-PLLA, however, can improve Ca-P formation after immersion in SCS.
The Effects of the Various Surface Treatments of Titanium on Cellular Activity of Osteoblast-Like Cells
Authors: Lee H. , Park J.W. , Choi Byung Ju , Yeo S.I. , Suh Jo Young
Published: March 2009

The response of osteoblast-like cells cultured on blasted and/or acid etching surfaces and the influence of surface texture or microtopography on cell attachment, cell proliferation, and the gene expression of the osteoblastic phenotype using ROS 17/2.8 cell lines were evaluated. The blasted and/or acid etching surfaces were significantly rougher in comparison to machined and etched surfaces (p < 0.05). On X-ray diffraction analysis, titanium hydride (TiH2) was observed on the surface etched with a mixture of HCl-H2SO4 solution, whereas TiH2 was not observed on machined and blasted surfaces. After 24 h incubation, most of the cells of all the groups had a flattened, polygonal shape and were fully spread, exhibiting the onset of proliferation. The MTT assay showed a significant decrease on the blasted surface compared to the machined surface at 7 day culture (p < 0.05). The expression of osteopontin mRNA, α1 (I) collagen mRNA, and alkaline phosphatase mRNA on rough surfaces was higher than on the machined surfaces, and was highest on the blasted surface at day 7.
In Vitro Studies of Inflammation and Contact Activation of Titanium Oxide Film
Authors: Zhao An Sha , Yang Ping , Leng Yong Xiang , Chen Jun Ying , Wang Jin , Wan Guo Jiang , Huang Nan
Published: March 2009

Ti-O film is a kind of potential biomaterial may be applied in medical devices. But the
mechanism of its good biocompatility is not so clear. This study revealed that when Titanium
oxide contact with macrophage and plasma, the activation, adhesion and secretion of
inflammatory molecule MCP-1 of macrophage is lower than reference material. Ti-O film also
show minor contact activation to plasma. So reducing the host reaction including contact
activation and inflammation may be the important reason for the good biocompatibility of Ti-O
film.
Evaluation of Sodium Titanate Coating on Titanium by Sol-Gel Method In Vitro
Authors: Wang Fang Fang , Liao Yun Mao , Wang Min , Gong Ping , Li Xiao Yu , Tang Hua , Man Yi , Yuan Quan , Wei Na , Tan Zhen , Ban Yu
Published: March 2009

In this study, an exclusive sodium titanate (Na2Ti6O13) coating on titanium was fabricated
by sol-gel method and evaluated in vitro. The coating was characterized by SEM and XRD. The
bioactivity of the Na2Ti6O13 coating was evaluated by the biomimetic growth of apatite on its surface
after soaked in an acellular simulated body fluid (SBF) for a period of time. In vitro osteoblasts
culture was carried out to determine cytocompatibility by the measurement of the proliferation and
alkaline phosphatase (ALP) activity of the cells. XRD patterns showed that Na2Ti6O13 was well
crystallized when the coating was heated at 800°C. SEM observation exhibited that the Na2Ti6O13
coated titanium had a homogeneous surface without any cracks. After immersion in SBF, the apatite
layer can be formed on the coating. The cells culture showed that the osteoblasts grew well on the
Na2Ti6O13 coated titanium. It can be concluded that Na2Ti6O13 coating on titanium obtained by
sol-gel method is bioactive.
Preliminary Study on the Biocompatibility of Calcium Phosphate Bone Cement Containing N,O-Carboxymethyl Chitosan
Authors: Huang Qi , Cao Feng , Li Dong Xu
Published: March 2009

N,O-carboxymethyl chitosan (CMCTS) was added in Calcium phosphate bone cement (CPC). A
preliminary study was carried out in order to evaluate the biocompatibility of CPC containing CMCTS. In vitro
tests were done using extract liquid from normal saline. The result showed that the biological reaction complied
with standards of GB/16886 and the composite might have good biocompatibility.
Clinical Results of Total Knee Arthroplasty by Using Improved Cement Technique by Interposing Hydroxyapatite Granules
Authors: Kim Sok Chol , Oonishi Hironobu , Oonishi Jr. Hiroyuki , Ohashi Hirotsugu
Published: March 2009

Improved cement technique by interposing less than two layers of hydroxyapatite (HA) granules between bone and bone cement at the cementing (Interface Bioactive Bone Cement : IBBC) have been performed in total knee arthroplasty (TKA). 140 knees (120 patients) could be followed up clinically and radiologically. As a control, clinical results of TKA with conventional cementing (Non-IBBC) were used. In IBBC cases, the appearance rate of the radiolucent lines on the tibial components and the periprosthetic osteolysis of the tibial components were significantly low. In IBBC, bone cement bound to HA mechanically immediately after surgery and HA granules bound to the bone physicochemically after bone ingrowth into the spaces around the HA granules. Thus, we believe that IBBC is a method combining the advantage of cementless HA coating and bone cement.
The Effect of Lif-Maleic Acid Added Calcium Aluminate Bone Cement and Ca-PMMA Composite Bone Cement on Bone Regeneration in Rat Calvarial Defects
Authors: Jung Ui Won , Shin J.A. , Chae K.J. , Lee Yong Keun , Kim Chong Kwan , Choi Seong Ho
Published: March 2009

The purpose of this study was to evaluate histologically the effect of LiF-maleic acid
added calcium aluminate (LM-CA) bone cement and calcium aluminate-polymethylmethacrylate
(CA-PMMA) composite bone cement on bone regeneration in rat calvarial defect. After calvarial
defects in 8 mm in diameter were created, three groups of 10 animals, a total of 30, each either
received LM-CA bone cement, CA-PMMA composite bone cement or a sham-surgery control.
Histologic analysis was done at 2 weeks and 8 weeks of healing periods. We concluded that LM-CA
bone cement can be used as a bioactive bone graft material due to ability of bonding to the existing
bone and CA-PMMA can be used as a graft material for augmentation of bone-volume due to
dimensional stability.
Control of Protein Initial Burst from Zinc-Hydroxyapatite / Poly(L-Lactide) System
Authors: Tonegawa Toru , Ikoma Toshiyuki , Chen Guo Ping , Tanaka M.
Published: March 2009

Control of protein release without the initial burst from zinc containing hydroxyapatite porous microparticles (Zn-HAp) was investigated with a novel formulation method. The formulation method was a coat of polyL(L-lactide; PLA) on the microparticle with nano-thickness, which obviously suppressed the initial burst of protein release compared with the microparticles without the formulation, the coat of PLA. The HAp/PLA microparticle with 1-20μm of the size distribution was available for the drug delivery carrier of proteins without the degradation.
Biomimetic Apatite/Polycaprolactone (PCL) Nanofibres for Bone Tissue Engineering Scaffolds
Authors: Ngiam M. , Hayes T.R. , Dhara S. , Su B.
Published: March 2009

Chemical treatment of polycaprolactone was carried out to bioactivite the
biodegradable polymer for bone tissue engineering application. The results show that surface
modifications are necessary to introduce functional groups such as carboxylic groups for the
effective induction of apatite nucleation, prior to SBF treatment. The functional groups, acting
as anchors between the polymer and the apatite nuclei, dictate the duration of the induction
period need for apatite nucleation. After the surface treatment with sodium hydroxide solution,
the apatite nuclei will form and grow spontaneously into a dense and uniform layer of apatite,
by taking up Ca2+ and PO4
2- ions that are present in the SBF, as SBF is supersaturated with
respect to apatite. Similar surface treatment was applied to electrospun PCL nanofibres.
Biomimetic apatite/PCL nanofibres were formed which can potentially be used as bone tissue
engineering scaffolds.
Characterization of Y2O3, CeO2 and Y2O3+CeO2 Doped FGM Tetragonal ZrO2 Ceramics by Spark Plasma Sintering
Authors: Huang Shui Gen , Van der Biest Omer , Vleugels Jef , Vanmeensel Kim , Li Lin
Published: March 2009

In this study, 2 mol% Y2O3 (2Y), 1 mol% Y2O3+6 mol% CeO2 (1Y6Ce) and 12 mol%
CeO2 (12Ce)-doped tetragonal ZrO2 ceramics were made by spark plasma sintering (SPS) for 2 min
at 1450°C under a pressure of 60 MPa. The influence of stabilizers on microstructure, phase and
mechanical properties of the ZrO2 ceramics was investigated. After sintering, the 2Y and 1Y6Ce
were intact, containing full tetragonal ZrO2 phase on the polished cross-sectioned surface, whereas
the 12Ce exhibited macro-cracks, corresponding to a large amount of monoclinic ZrO2 phase.
Graded microstructure and mechanical properties were observed in the 1Y6Ce, showing a gradually
decreased fracture toughness from sample edge towards centre, together with the slight decreased
hardness. The 2Y had a uniform microstructure and mechanical properties. The formation of the
graded structure and toughness profile was explained in terms of the gradual CeO2 reduction to
Ce2O3 in the Y2O3+CeO2 doped ZrO2 ceramics.
Geometry Effect on the Thermal Shock Response of Al2O3/ZrO2 Multilayered Ceramics
Authors: Bermejo Raúl , Supancic Peter , Lube Tanja
Published: March 2009

In this work, the geometry effect on the thermal shock behaviour of a nine layered Al2O3-
5%tZrO2/Al2O3-30%mZrO2 ceramic fabricated by slip casting has been studied. A finite element
model has been used to estimate the magnitude and location of the maximum thermal stresses in the
layered material as well as the influence of the variation of this layered architectural design in the
thermal shock crack initiation and extend throughout the specimens of study. Experimental tests on
various samples have been carried out to validate the model. The residual stress distribution profile
in the laminate, due to the elastic mismatch of the different layers along with the zirconia phase
transformation on the Al2O3-30%mZrO2 layers, conditions the thermal shock response of the
material. It is demonstrated how the variation of the outer most layer thickness in the laminates
modifies the stress state in the surface, affecting the thermal shock crack initiation.
Development of Thin Ceramic Coatings for the Protection against Temperature and Stress Induced Rumpling of the Metal Surface of Turbine Blades
Authors: Baufeld Bernd , Van der Biest Omer
Published: March 2009

In order to obtain a protection against temperature and stress induced detrimental
rumpling of the metal surface of turbine blades, thin ceramic coatings are suggested. As a cheap and
fast method for the fabrication of a ceramic zirconia coating, electrophoretic deposition on a Ni
based superalloy is described. Crack free, 0.15 mm thick coatings with homogenous morphology
were obtained. The Young’s modulus and the damping property of the ceramic coating, derived
from the impulse excitation technique, are investigated as a function of the temperature up to
1000°C.
Nucleation of Shear Bands on EB-PVD Thermal Barriers Coatings under Hertzian Indentations
Authors: Gaillard Yves , Jiménez-Piqué Emilio , Bartsch Marion , Anglada Marc
Published: March 2009

In this paper the formation of shear bands in columnar EB-PVD thermal barriers coatings is studied. In particular, critical parameters of nucleation of shear bands, such as contact pressure and initiation of cracks in the columns, are extracted from the experimental results. The pertinence of these parameters is discussed respecting to the stress field induced in the material during the indentation.
Ti – Al Intermetallic Layers Produced on Titanium Alloy by Duplex Method
Authors: Wiecinski Piotr , Garbacz Halina , Ossowski M. , Wierzchoń Tadeusz , Kurzydlowski Krzysztof Jan
Published: March 2009

The paper presents the results concerning the microstructure of Ti – Al
intermetallic layers produced on a TA6V titanium alloy by the “duplex method”. This method
combines vacuum evaporation coating of aluminum with glow discharge assisted heat
treatment of the deposited films. It has been found that this combination of surface
engineering techniques yields multi – layered films of the diffusive character. The films
contain intermetallic phases from Ti – Al system which ensure a high microhardnes and good
wear resistance. It is finally suggested that these properties can significantly widen application
range of titanium alloy parts in aerospace.
Mechanical Properties of Ceramic Laminates
Authors: Lube Tanja
Published: March 2009

The progress of research efforts on the mechanical properties of ceramic laminates is reviewed. Laminates with weak interface are described with respect to their failure mode and the criterions to achieve graceful failure. For laminates with strong interfaces basic principles concerning the residual stresses and their influence on crack propagation are introduced. The implications for strength, indentation strength, strength distributions, macroscopic R-curves and threshold strength are discussed.
Design of Shape Memory Alloy Actuated Deformable Airfoil for Subsonic Flight
Authors: Leung R.C.K. , Lau Alan Kin Tak , Yu S.F.
Published: March 2009

Aerodynamic surfaces for subsonic flight vehicles are usually designed primarily with
the cruise condition in mind. With this objective in mind, the design of these aerodynamic surfaces,
which usually exist as airfoils on the vehicles, are in general suboptimal for actual situation because
they must be used for takeoff, landing, and maneuver in addition to cruise condition [1]. Therefore,
it would be always desirable to design an airfoil with the ability to adapt to its current flow
condition and alter its shape to remain the efficiency at any speed. The present paper reports a
design of an airfoil with NACA 0012 profile which aims to deform the airfoil shape under the
actuation the shape memory alloy (SMA) actuators embedded in it. The SMA actuators design to
alter the aerodynamic lift and drag in a subsonic flow. The feasibility of the design is examined and
discussed in the light of the change in lift to drag ratio and the power budget of the actuation.
Piezoresistance Behaviour of CFRP Cross-Ply Laminates with Transverse Cracking
Authors: Inoue Hiroki , Ogi Keiji
Published: March 2009

This paper describes the piezoresistance behavior in CFRP cross-ply laminates with
transverse cracking loaded in tension. The resistance change due to transverse cracking and the gage
factor (the rate of resistance change per mechanical strain) for each transverse crack density were
experimentally measured during loading/unloading cycles. The resistance change-strain curves in the
unloading/ reloading processes show the bilinear behavior where two gage factors are defined as the
slopes of the bilinear curve. The residual resistance change after full unloading increases almost
linearly with the mechanical strain while the gage factors do not always increase with the strain. The
residual resistance change and gage factors are associated with transverse crack density on the basis of
an equivalent resistance circuit.
Magnetic Alignments of Ba-Ferrite Particles in Suspension
Authors: Li Jing Long , Sano Saburo , Xiong Jiang Tao , Zhang Fu Sheng , Wang Zhong Ping
Published: March 2009

Ba-ferrite particles were dispersed into distilled water to make stable slurry, which was then
slip cast in transverse magnetic field. The water drainage from the slurry was performed by vacuum
evacuation to solidify the slurry into a cake – like sample. To obtain high degree of alignments, the
slurries were slip cast in static – / pulsed – magnetic field and by using two separate steps of magnetic
orientation and drainage. The particles turned their faces to the magnetic field and formed long chains
stacked immediately while the magnetic field was applied, of which high induction density led to high
degree of alignments. It is necessary to correspond with the drainage, gravity and magnetism so as to
suppress the tendency of distortion or cracking of the sample as the aligned long chains of the particles
tend to break into pieces and cave in randomly, which eventually destroys the particle alignments.
Synthesis of Fine Grain Ti3SiC2 by Spark Plasma Sintering with Additive of Aluminum
Authors: Han Ruo Bing , Pan Wei , Fang Ming Hao , Shi Sui Lin , Qi Long Hao
Published: March 2009

High purity polycrystalline titanium silicon carbide (Ti3SiC2) was synthesized by spark plasma sintering (SPS) with additive of Aluminum at low temperature of 1100~1300oC. XRD results showed that the content of Ti3SiC2 in the synthesized bulks increased with the addition of Aluminum, however, the lattice parameters of Ti3SiC2 samples with different amounts of additive exhibited scarcely change. With a starting powder of 1Ti/1.2Si/2TiC/0.1Al (molar ratios), dense Ti3SiC2 ceramic (98vol.%Ti3SiC2) was obtained by sintering at 1100oC for 5min under a pressure of 30MPa. Fine Plate-like grains of the samples with sizes of 2~6μm could be identified by scanning electronic microscope (SEM).
Effect of Aluminum on Fabrication of Ti3SiC2 by Mechanical Alloying and Spark Plasma Sintering
Authors: Jin Song Zhe , Liang Bao Yan , Li Jing Feng , Li Li
Published: March 2009

In the present study, we fabricated high purity and electrically machinable Ti3SiC2 ceramics by mechanical alloying and subsequent spark plasma sintering. The effect of a trace amount of Al on these synthesis processes was examined. Our results showed that Ti3SiC2 could be synthesized by high energy milling. Spark plasma sintering of mechanically alloyed powder at the temperatures of 1000-1200°C produced nearly single-phased Ti3SiC2 materials. The purity of the sintered Ti3SiC2 bulk was remarkably increased by addition of a small amount of Al. Ti3SiC2 with a purity of 99.3 wt% and a relative density of 98.9% was obtained by mechanical alloying and subsequent spark plasma sintering from a starting mixture composed of n(Ti) : n(Si) : n(Al) : n(c) = 3 : 1 : 0.2 : 2 at 1100°C.
Processing and Characterization of Carbothermal Reduction and Nitridation from Kaolinite-Polyacrylamide Intercalation Compound
Authors: Wang Lin Jiang , Wu Da Qing , Xie Xiang Li , Zhu Wen Feng , Gao Li
Published: March 2009

The kaolinite-polyacrylamide intercalation compound was prepared by the displacement reaction
of the kaolinite-formamide intercalation precursor with acrylamide and the polymerization under
140°C for 15h with the catalysis of dibenzoyl peroxide. Sialon was synthesized from kaolinite-polyacrylamide
intercalation compound by carbothermal reduction and nitridation (CRN) processing at 1400°C.
The kaolinite-carbon mixture and its CRN product were also prepared for the comparison with the CRN
result of intercalation compound. XRD, FT-IR, and TEM were used to characterize the phases, structure
and morphology of products. In the CRN product from the intercalation compound, β′-sialon is the main
phase. And the reduction and nitridation rate from the intercalation compound was greater than that from
the mixture. There was higher sialon phase’s content and lower mullite phase’s content in the CRN
product from the intercalation compound than that from the mixture. The CRN processing of kaolinite
intercalation compound is a novel and effective method of sialon synthesis.
TiC/Ti Composite Layers Fabricated by Laser Surface Alloying
Authors: Zhang Jian Bin , Fan Ding , Dai Jing Jie , Sun Yao Ning
Published: March 2009

Laser surface alloying is an attractive processing to improve surface hardness, wear and corrosion resistance. In this paper, a continuous wave CO2 laser was used to irradiate commercially pure titanium surface with pre-placed active carbon powders in argon atmosphere. A compact, well-adherent, and crack-free TiC/Ti composite layer was obtained. The microstructure and phase constitution of the alloyed layers were determined and analyzed, and the micro-hardness was measured. The result of X ray diffraction (XRD) analysis shows that the alloyed layers contain TiC and Ti (martensite). The scanning electron microscopy (SEM) observation shows TiC growth morphologies have a well-developed dendrite, cellular dendrite, globular microstructure and cross-petal microstructure. The mechanism of the formation of titanium carbides is discussed. Micro-hardness of the laser surface alloyed layer was improved to 420 Hv as compared to 200 Hv of the as-received commercially pure titanium.
Microstructure of Different Rare-Earth-Doped α-Sialon Ceramics
Authors: Liu Chun Feng , Ye Feng , Zhou Yu , Meng Qing Chang , Wang Yong Liang
Published: March 2009

The densified α-sialon ceramics with the compositions RE0.333Si10Al2ON15 (RE= Yb,Y, Dy,
Sm and Nd) were prepared by a two-step hot-pressing sintering. The ceramics doped with smaller cations
(Yb3+, Y3+ and Dy3+) are fully composed of α-sialon, while the larger cation-doped ceramics (Sm3+ and
Nd3+) exist a few M′ (RE2Si3-xAlxO3+xN4-x) phases. A small amount of β-sialon phases are also found in
the Nd-doped sialon. Microstructure observation indicates that Yb-α-sialon consists of equiaxial grains,
but when increasing the radius of the doped cations, the elongated α-sialon grains form and the aspect
ratio of grain increases slightly. TEM observation indicated that almost no intergranular phases exist in
the α-sialon doped with smaller cations, but a few exist in Sm- and Nd-doped α-sialon. Some elongated
α-sialon grains with grain core were found. EDX results suggest that the compositions of the grain shell
and that of the core are different. Surrounding the grain core, some misfit dislocations were seen.
Synthesis and Properties of Ternary Carbide Ti3AlC2 Ceramics
Authors: Zhou Yang , Zhai Hong Xiang , Gao Li Qiang , Ai Ming Xing , Huang Zhen Ying , Li Shi Bo , Zhang Zhi Li , Li Cui Wei
Published: March 2009

Polycrystalline bulk samples of ternary carbide Ti3AlC2 ceramics were fabricated by reactively
hot-pressing a mixture of Ti, Al, and graphite powders with and without Sn additive. The effects of
sintering temperature, time and addition of Sn on the purity, mechanical properties and microstructure of
Ti3AlC2 were investigated. The result showed that the TiC content was strongly influenced by sintering
temperature for the Ti3AlC2 samples without Sn additive, and the most suitable sintering temperature to
create the lowest TiC content was 1400°C. The addition of Sn additive led to a distinct decrease in TiC
content. The flexural strength of the testing materials had close relation with the TiC content and sintering
time. A certain content of TiC second phase and longer sintering time were helpful to improving the
flexural strength. The sample sintered at 1400°C for 2 h possessed the highest flexural strength.
Preparation and Property Study of 3D Cf/Si-Ti-C-O Composites Fabricated with Polytitanocarbosilane by PIP Process
Authors: Wang Qi Kun , Hu Hai Feng , Zheng Wen Wei , Ma Qing Song , Chen Zhao Hui
Published: March 2009

In this paper, 3D Cf/Si-Ti-C-O composites were prepared with a polytitanocarbosilane (PTC) via polymer infiltration and pyrolysis (PIP) process, and accordingly the mechanical, oxidation resisting and thermal shock resisting properties were investigated. The composites with density of 1.93g·cm-3 show rather high flexural strength (485.3MPa) and fracture toughness (19.95MPa⋅m1/2), and typical non-brittle fracture failure mode. After oxidation treatment at 1300°C for 10 minutes in air, the flexural strength of the samples is 306.2MPa, with 63% strength retention. After 5 times of thermal shock tests from room temperature to 1300°C, the flexural strength of the samples is 408.9MPa, about 85% strength retention. SEM observation also testifies non-brittle failure because many fibers are pulled out on the fracture surface. After oxidation treatment, the matrix shows no changes from XRD measurement.
Processing and Properties of 2D Cf/Si-O-C Composites Using Silicone Resin
Authors: Jian Ke , Chen Zhao Hui , Ma Qing Song , Hu Hai Feng
Published: March 2009

SR-249, a kind of polysiloxane (PSO), was used as the precursor for the first time to fabricate carbon fiber cloth reinforced silicon oxycarbide (2D Cf/Si-O-C) composites. The cure and pyrolysis of the SR-249 as well as the mechanical properties, oxidation and thermal shock behavior of the composites were investigated in the paper. The flexural strength and fracture toughness of the composites reached 217.6 MPa and 12.5 MPa·m1/2, respectively. After soaked at 1300°C under the static air for 10 min, the composites retained 58.5% flexural strength and 64.5% fracture toughness. The thermal shock behavior of the composites was studied by water quenched method. The composites retained 49.3% flexural strength and 47.4% fracture toughness after 10 times of quenching from 1200 to 20°C.
Fabrication of SiC/SiC Composites Using both Chopped Fiber and a Hybrid Reinforcement of Chopped and Continuous Fibers
Authors: Feng Qian , Dong Shao Ming , Ding Yu Sheng , Zhou Qing , Kohyama Akira
Published: March 2009

Chopped fiber and a hybrid reinforcement of chopped and continuous fibers were used for fabricating SiC/SiC composites. Under the selected sintering pressure, the composite sintered at lower temperature (1820°C) had lower density. Increasing temperature to 1850°C, the density of the composite reached at a higher level. However, pores still existed and mainly distributed in the areas the fibers accumulated, especially inside of the fiber bundles. Densely sintered matrix still could be found in the composite sintered at 1820°C, 15 MPa. In the areas with the fibers accumulated, matrix was relatively weak so that the cracks were easily propagated leading to the delamination during bending test. When continuous fiber was included into the chopped fiber reinforced composite, a hybrid reinforcing mechanism was obtained. This kind of composite had obviously improved toughness and strength. On the fracture surface, the pulled out fibers that were perpendicular to the fracture surface were increased.
Phase Evolution of Aluminum-Chromium-Phosphate Binders during Heat-Treatment
Authors: Zou Chao , Zhang Da Hai , Li Yi , Weng Wen Jian , Cheng Kui , Song Chen Lu , Zhao Gao Ling , Du Pi Yi , Shen Ge , Wang Jian Xun , Han Gao Rong
Published: March 2009

Aluminum phosphate is one of the best inorganic binders, and the addition of chromium oxide can improve the properties of the binder. In this work, the phase evolutions in chromium phosphate system and aluminum-chromium-phosphate system during heat-treatment were investigated. The initial binder solutions were prepared by dissolving Al(OH)3 and Cr2O3 in aqueous H3PO4 solution. The binder solutions consolidated at 100°C. The as-consolidated products were heated at different temperature. The experimental results showed the phase evolution of the consolidated products as: amorphous phase in 300~800°C, Cr(PO3)3 and Cr4(P2O7)3 in 900~1200°C for chromium phosphate system binder; amorphous phase in 300~1000°C, Cr(PO3)3 and AlPO4 in 1100°C, Cr4(P2O7)3 and AlPO4 in 1200°C for aluminumchromium- phosphate system binder. The addition of chromium oxide demonstrates to strengthen amorphous network, which further improves the thermal stability.
The Influence of Thin Film Thickness on the Characteristics of Bismuth Titanate Oxide
Authors: Yang Cheng Fu , Chia Wei Kuo , Chen Ying Chung , Cheng Chien Min
Published: March 2009

Bi4Ti3O12
thin films were deposited on Pt/Ti/Si(p-100) substrate by RF magnetron
sputtering at room temperature, and crystallized in a RTA furnace at temperature of 675°C for 10
minutes. SIMS analysis identifies that bismuth content in the Bi4Ti3O12 thin film reduced slightly
from the surface into a depth of approximately 200 nm. XRD patterns revealed (117) phase was
dominated regardless the film thickness, and the intensity of the other peaks increased with the
increase of film thickness. (200) peak became dominant when the thickness of films were greater than
680 nm. SEM observation showed that the grains were stripe plate-like, and the grain size increased
with the increase of film thickness. Dielectric constant increased with the increase of film thickness,
and kept around a certain value with the thickness ranging from 300 to 640 nm, then it rose again as
the film thickness above 680 nm. The leakage current and electrical breakdown also strongly
depended on the film thickness.
Preparation and Morphology of Mullite Whiskers by Sol-Gel Method
Authors: Wang Zhou Fu , Du Chun Tian , Wang Xi Tang , Zhang Bao Guo
Published: March 2009

Mullite whiskers were prepared by sol-gel method. The preparing conditions, the morphology
and crystallite phase of the mullite whiskers were studied by Thermal analysis, XRD and SEM. The
results demonstrate that the uniform mullite whiskers with high aspect ratio were obtained in properly
preparing conditions and appropriate amount of fluorides.