bluuebunny/crossref_metadata_2025 huggingface dataset:
A Numerical Study of MSD in Aircraft Lap Joints
Authors: Chen Yue Liang , Yu Da Zhao , Duan Cheng Mei
Published: March 2009

Many military aircraft have reached or exceeded their original design life, and have been
subject to significant increase in maintenance and repair cost due to multiple site damage (MSD). In
order to assessing the effects of MSD on the structural integrity of aircraft lap joints, the wing lap
joint of certain model military aircraft with MSD was analyzed using special code FRANC2D/L. The
rivet holes along the top row of the outer skin of lap joint were considered as the independent
structural unit for the simulated MSD cracks. The stress intensity factors (SIFs) at each crack tip with
different distribution loads at the rivet holes were computed and show that the analysis results have
good coherence with the available literature data. It also shows that the SIF at each crack tip s a
function of crack length can be calculated by the crack growth simulation capability of FRANC2D/L.
The SIF values are not sensitive to the rivet load distribution manner, which has seriously influence
on MSD crack growth direction. Rivet loading can be best molded quadratic load distribution over
one half of rivet hole relative to uniform load distribution and point load. As a result of this analysis,
it is postulated that for MSD in aircraft lap joints, compliance measurements may provide a useful
tool for assessing the structural integrity of the lap joints.
The Crack Growth Life Predictions for High Cycle Dynamic Components
Authors: Mu Zhi Tao , Liu Wen Lin , Jin Ping
Published: March 2009

Using of a safe life approach is necessitated by the small critical crack sizes and rapid crack
growth rates resulting from the severe vibratory environment of rotorcraft. However Based on the
success of damage tolerance initiative for airframe structure, a crack growth based on damage
tolerance approach is being examined for implementation into the design and management of
dynamic components. In this paper the crack growth behavior in low cycle fatigue (LCF) and high
cycle fatigue (HCF) are compared and the accuracy of several damage tolerance analysis methods in
determining the crack growth life from an initial detectable crack size 1.25 mm to 12 mm for a
rotorcraft main rotor yoke are investigated. The real rotorcraft materials measured by experiment and
the fatigue load mean frequency spectrum based on statistical usage spectrum are adopted. The crack
growth equations used in the programs are discussed to provide a basis for understanding the results.
The results show that the load less than the safe fatigue limit has an important effect on crack
growth life and it is reasonable for the material that the cut-off stress ratio for the threshold stress
intensity factor range is set 0.7.
Determination of Splitting Force in Process of Fracture Splitting Connecting Rod
Authors: Zhang Zhi Qiang , Yang Shen Hua , Kou Shu Qing , Zhao Yong
Published: March 2009

Splitting force is the key to the process of fracture splitting connecting rod. In this paper,
numerical simulation is made in the process of fracture splitting Jetta car connecting rod by using
software MSC.MARC. Through analysis, the curve between J integral and splitting force is
established. According to the experiential formula of impact toughness and fracture toughness,
critical J integral ( JIC ) can be achieved. After getting JIC , the splitting force can be determined by
linear interpolation method and verified by tensile experiment and the error is below 1%. It is
proved that this method can also used to analyze other kinds of connecting rods with different
materials.
Grinding Acoustic Emission Classification in Terms of Mechanical Behaviours
Authors: Chen Xun , Griffin James
Published: March 2009

The material removal in grinding involves rubbing, ploughing and cutting. For grinding process monitoring, it is important to identify the effects of these different phenomena experienced during grinding. A fundamental investigation has been made with single grit cutting tests. Acoustic Emission (AE) signals would give the information relating to the groove profile in terms of material removal and deformation. A combination of filters, Short-Time Fourier Transform (STFT), Wavelets Transform (WT), statistical windowing of the WT with the kurtosis, variance, skew, mean and time constant measurements provided the principle components for classifying the different grinding phenomena. Identification of different grinding phenomena was achieved from the principle components being trained and tested against a Neural Network (NN) representation.
Study on Mechanism and Experiment of Engine Cylinder by Laser Honing
Authors: Zhang Yong Kang , Kong De Jun , Fu Y.H. , Lu Jin Zhon , Feng Ai Xin , Ren Xu Dong
Published: March 2009

The diesel engine cylinder was processed by laser honing (LH) device, the structure
morphology was observed with scanning electric mirror (SEM), and lubricant consumes and wear
performances were measured, at the same time the mechanism of LH and effects of laser parameters
on LH results were analyzed. The experimental results are shown that LH is a kind of phase
transformation treatment by laser, which processes a hardening belt in the certain distributing form
on the work-piece surface, and forms the hardness distribution of soft and hard material
alternatively; LH may lower the engine oil consumes 30%-60%, and reduce the pollution of the
catalyst machine, and lower the grain let of the engine oil 25%-30%. LH intentionally machines the
grain cave, which has the certain angle, depth, and width etc.. The surface microcosmic sculpting
has the lubricating function for usage process, and storage and transport lubricant, which improves
the rubbing condition, then lower the part wear and increase the other performances. The
short-wave laser is more applicable to the LH process, which improves the lubrication condition,
and increases the service life of the engine and the efficiency, and lowers the engine oil consumes.
Surface Characteristics of Ceramics Milled with Abrasive Waterjet Technology
Authors: Feng Yan Xia , Huang Chuan Zhen , Wang Jun , Lu X.Y. , Zhu Hong Tao
Published: March 2009

The surface characteristics of Si3N4 ceramics milled with abrasive waterjet milling
technology is studied. The milled surface characteristics and the effect of process parameters on
milled surface roughness are analyzed. The results show that the milled surface roughness ranges
between 0.55 and 1.1um at the milling conditions under consideration and is changed with the
change of process parameters. The milled surface roughness will be significantly decreased at the
milling conditions of lower water pressure and larger lateral spacing. The effect of nozzle traverse
speed on milled surface roughness is complex, but a traverse speed of 1000mm/min is the optimum
speed for AWJ milling Si3N4 ceramics. The milled surface roughness first decreases then increases
with an enhancement of standoff distance from 10mm to 30mm, and it also significantly decreases
with the increase in abrasive mesh. Therefore, the medium standoff distance of 20mm and finer
abrasive are the optimum conditions for AWJ milling Si3N4 ceramics with the process parameters
under consideration.
Fusion Identification for Wear Particles Based on Dempster-Shafter Evidential Reasoning and Back-Propagation Neural Network
Authors: Cao Y.B. , Xie X.P.
Published: March 2009

Based on Back-Propagation neural network and Dempster-Shafter evidential reasoning, a
fuse classification method for identifying wear particles is putted forward. Firstly, digital wear
debris images are dealt with images processing methods. Then from the wear particles images, wear
particles characters can be obtained by means of statistical analysis and Fourier analysis. Later, an
integrated neural network made of two sub-neural networks based on statistical analysis and Fourier
analysis is established, and some typical wear particles features as training samples are provided.
After each sub-BP neural network has been trained successfully, the preliminary diagnosis of each
sub-neural network is achieved. By using of the dempster-shafter evidential reasoning, the finial
fusion diagnosis results are obtained. In the end, a practical example is given to show that the fusion
results are more accurate than those with a single method only.
Ceramic Grindability Evaluation with PCA Method
Authors: Yu Ai Bing , Chen Yao , Jia Da Wei , Tian Xin Li
Published: March 2009

Mathematical evaluation model for ceramic grindability was presented based on principal
components analysis (PCA) method. Sample matrix was constituted with influence factors of
ceramic grindability. Principal components and weight vectors were determined through calculation
of eigenvalues and eigenvectors of correlation matrix, which was deduced from sample matrix.
Comprehensive values could be obtained through eigenvectors and weights vectors. Seven ceramics
were selected as evaluation example. Material property parameters including hardness, fracture
toughness, Young’s modulus and bending strength were selected as influence factors of ceramic
grindability.According to the comprehensive evaluation values, grindability rank of seven materials
from better to worse was B4C, sintering SiC, high-purity Al2O3, hot-pressed SiC, sintering Si3N4,
hot-pressed Si3N4 and Y-TZP. Moreover, the determination of weight vectors could offer reference
for other comprehensive evaluation methods. Research results suggest that PCA is a reasonable and
available method to determine the rank of ceramic grindability.
Analysis of Mechanical Property of Crystal KDP and Simulation of Ultra-Precision Cutting Process in the Ductile Mode
Authors: Chen Ming Jun , Wang Jing He , Chen X.M. , Liang Ying Chun
Published: March 2009

In order to study mechanical property with different crystal-plane and different crystal orientation of the crystal KDP, nano-indentation experiments are first done. The mechanical properties of crystal KDP, such as elastic modulus, yielding stress, are obtained from the analysis of the experimental curve. To obtatin the stress-strain curves of crystal KDP, by using the spherical tip can get characteristic of continuous strain, the spherical indentation experiments is proposed firstly and carried out. According to obtained parameters, A finite element cutting model of crystal KDP is established. The cutting process of crystal KDP is simulated by the model, and the influence of rake angle and depth of cut on chip and surface quality is studied. The theory shows that when the cutter’s rake angle is in the range of -40° to -45°, an perfect super-smooth KDP crystal surface will be obtained. Finaly, the experiments is carried out on special ultra-precision machine tool for crystal KDP by ourself devoloping. Experiment results show that when the cutter’s rake angle is about -45°, an super-smooth surface (rms: 6.521nm and Ra: 5.151nm )is obtained on the plane (001), and this experiment certified correctness of theory analysis.
Development of 3R Diamond Wheel by Thermoplastic Resin Bond
Authors: Matsuura Hiroshi , Kunieda Yasuhiro , Yoshihara Nobuhito , Yan Ji Wang , Kuriyagawa Tsunemoto
Published: March 2009

A completely new diamond wheel, named the 3R wheel, has been developed. The 3R
wheel has three unprecedented functions, reconfiguration, restoration and recyclability, and is
molded from a mixture of special thermoplastic resin filler and diamond powder. The concept of the
3R wheel is to control the quantity and the position of abrasive material by actively using heat. In
this study, tungsten carbide (WC) was ground using a thermoplastic resin bonded diamond wheels
(radius 1.4 mm) with three different concentrations of 1500 grain size abrasive. As a result, a
grinding ratio of over 200 and 18 nmRa roughness was achieved without dressing. In addition, a
large quantity of abrasives was confirmed on the wheel surface by observation.
Manufacturing Porous Diamond with Skeleton Structure from PCD by EDM and its Application to Grinding Tools
Authors: Suzuki Kiyoshi , Zhang Danyang , Shiraishi Yoichi , Iwai Manabu , Uematsu Tetsutaro , Ninomiya Shinichi , Sano Sadao
Published: March 2009

This paper proposes a new PCD (polycrystalline diamond) wheel with porous skeleton
structure realized by removing the cobalt binder from PCD by EDM (electrodischarge machining),
and investigates the grinding characteristics of the wheel. The pores are made successfully on PCD
by adopting appropriate EDM conditions. The efficiency of making the pores is found to be higher,
when the size of the diamond grains in the PCD material is small, and jumping motion to the copper
electrode is not given during the EDM. A porous PCD grinding wheel made by this method using a
rotating circular PCD (grain size of 10'm) disc of 20mm diameter has a good skeleton structure
with sufficient projections on the wheel surface. A satisfactory grinding characteristics with a
surface finish of Ra=0.02'm in grinding on a tungsten carbide work is achieved.
High Speed Milling of Ti6Al4V Alloy with Minimal Quantity Lubrication
Authors: Zhao Wei , He Ning , Li Liang
Published: March 2009

Minimal quantity lubrication (MQL) machining has been accepted as a successful semi-dry
application because of its environmentally friendly characteristics and satisfactory performance in
practical machining operations. However, seldom investigation has been done in MQL machining of
titanium alloy at high cutting speeds. In this paper, high speed milling experiments with MQL9 ml/h
of oil in a flow of compressed air have been carried out for a widely used titanium alloy Ti6Al4V.
Uncoated cemented carbide inserts have been applied in the experiments. Within the range of cutting
speeds employed (190 m/min~300 m/min), the cutting performance of MQL has been investigated
when peripheral milling the titanium alloy Ti6Al4V in terms of cutting forces, surface roughness, tool
life and wear mechanism. The results show that, compared to dry machining, MQL machining brings
about a significant reduction in cutting forces and surface roughness, and it also gives rise to a notably
prolonged tool life.
Finite Difference Modeling of Cutting Temperature in Machining of A6061-T6 Aluminum Alloy at Ultra High Cutting Speeds
Authors: Obikawa Toshiyuki , Basti Ali , Shinozuka Jun
Published: March 2009

The finite difference method was applied to simulate temperature distribution in the workpiece, cutting zone and tool in the orthogonal cutting process with multilayer coated sintered alumina tools. The analysis was conducted under different cutting speeds, while experiments were carried out to measure temperatures in different positions of the tool rake face using tools with built-in thin film thermocouples developed by the authors. The temperature distribution calculated along the rake face was consistent with experimental data. This proved that the finite difference modeling developed can be applied to the prediction of cutting temperatures of aluminum alloys for a range of ultra high cutting speeds.
A Comparative Study of Stone Sawing with Thin and Normal Blades
Authors: Han Q.L. , Li Yuan , Xu Xi Peng
Published: March 2009

In this paper, an experimental study was conducted to compare the sawing of granite with
thin and normal blades. The power drawn by the spindle and horizontal and vertical forces were
measured. The width of sawing slot on the granite was examined after sawing. For both blades,
power and forces increase with the depth of cut. The width of sawing slots for the thin blade was
about 75% of the normal blade. The width of sawing slots for either thin or normal blade sawing
became narrower in larger depth of cut.
Study on Magnetic Barrel Machine Equipped with Three-Dimensional Arrangement of Magnets
Authors: Zhang Y. , Yoshioka Masato , Hira Shin-Ichiro
Published: March 2009

At present, a commercially available magnetic barrel machine equipped with permanent
magnets has some faults arising from constructional reason. That is, grinding or finishing ability is
different from place to place in the machining region, resulting in the limitation on the region we can
use in the container of workpieces. Therefore, in this research, authors made the new magnetic barrel
machine equipped with three dimensional (3D) magnet arrangement to overcome these faults. The
grinding ability of the new 3D magnetic barrel machine converted was experimentally examined, and
compared with that of the traditional magnetic barrel machine. As a result, it was shown that we can
use much broader region in the new 3D machine. It was also shown that the grinding ability became
higher. The distribution of barrel media in action was recorded by means of a high speed video
camera. It was clarified that the media rose up higher and were distributed more uniformly in the
container by the effect of the magnet block newly set up. It was supposed that this must be the reason
for the above-mentioned improvement of grinding ability.
An Experiment Investigation for Dynamics Characteristics of Grinding Machine
Authors: Jiang Y.X. , Tang Wei Xiao , Zhang G.L. , Song Qing Hua , Li B.B. , Du B.
Published: March 2009

In this article, modal experiments were used to analysis the dynamics
characteristics of the grinding machine. Static modal testing has validated the nature
frequency and the critical speeds were also recognized by dynamic racing experiment. In
grinding experiment, the surface roughness was investigated in different speed of workpiece
spindle. The way to reduce vibration that caused to bad surface roughness of workpiece was
also discussed. This experiment laid a foundation to optimize the structure parameter to
improve the dynamic character of the grinding machine.
Basic Properties of Coolant Supply Using a Coolant Flow Guided Flexible Sheet
Authors: Ninomiya Shinichi , Iwai Manabu , Suzuki Kiyoshi , Shiraishi Yoichi , Shimizu Toshiharu , Uematsu Tetsutaro
Published: March 2009

In order to improve the floating nozzle method, a new coolant supply method using a
coolant flow guided flexible sheet has been developed. In this paper, basic properties of the coolant
supply when the coolant flow guided flexible sheet method is used are investigated. At first, the
phenomenon of automatic adherence of the flexible sheet to the wheel surface is observed with a
high-speed camera. Next, the effect of the clearance between the sheet and the wheel surface is
experimentally investigated. It is found that the thickness of the coolant flow in this clearance is very
small as about 0.1mm, and can be controlled to some extent by controlling the coolant flow rate and
wheel rotation speed. Furthermore, it is clarified that the influence of the flexible sheet on the electric
power consumption of the main spindle motor is small.
Preparation of Hydroxyapatite-Alginate Gels as a Carrier for Controlled Release of Paclitaxel
Authors: Yoshioka Tomonori , Ikoma Toshiyuki , Monkawa Akira , Yunoki Shunji , Abe Tetsuya , Sakane Masataka , Tanaka M.
Published: March 2009

Hydroxyapatite (HAp)-alginate gels were developed as drug delivery carriers of the anti-cancer drug, water-insoluble paclitaxel (Taxol). The spray-drying technique was employed for loading the paclitaxel into spherical HAp microparticles with 1 to 20 μm in diameter. The microparticles loaded with 2.4 or 7.3wt% of paclitaxel were then mixed with sodium alginate, which was followed by Ca2+-mediated gelation. The compressive strength of the HAp-alginate gels and the release of paclitaxel from the gels in a medium were investigated in vitro. The alginate matrix was effective for the achievement of controlled release of anti-cancer drugs.
Tailoring of Multilayer Core-Shell Structure for the Controllable Release of Biologically Active Silicon and Strontium Ions
Authors: Gou Zhong Ru , Weng Wen Jian , Zhou Ja Bei , Du Pi Yi , Han Gao Rong
Published: March 2009

Nanocomposites consisting of biologically active ions, which can enhance cell viability
and activate gene expression, are regarded as promising bone regenerative materials. We report a
new method for the layer-by-layer (LbL) assembly of biologically active strontium ions in the
core-shell Silica@OCP system for an efficient controlled-release. The strontium ions were
assembled by using a pH-responsive electrostatic interaction to generate three-dimensional
gradients within the silica nanospheres, and then a porous OCP (octacalcium phosphate) shells was
coated on the microunits tailored by polyelectrolyte molecules. This core-shell-like microstructure
can achieve the multicomponents administration and controlled release of essential trace silicon and
zinc ions based on the barrier effect of OCP shell and pH-dependent manner, respectively.
Gene Expression Profile of Osteoblast-Like Cells on Calcium Phosphate Biomaterials
Authors: Takemura Taro , Fan Hong Song , Ikoma Toshiyuki , Tanaka M. , Hanagata Nobutaka
Published: March 2009

Gene expression profile of osteoblast-like cells cultured on dense disk materials and
porous materials of calcium phosphate ceramics was constructed from DNA microarray analyses.
The profile revealed that gene expression patterns of porous materials were significantly different
from those of dense disk materials. The porous materials had a capacity to induce expressions of
genes involved in osteoblast differentiation, while dense disk materials regulated gene expressions
related to osteoclastogenesis.
Repairing Periodontal Bone Defect with In Vivo Tissue Engineering Bone
Authors: Zhang Bi , Zhang X.J. , Bao C.Y. , Wang Q. , Yao Jin Feng , Fan Hong Song , Xiong C.D. , Zhang Xing Dong
Published: March 2009

The purpose of this study was to develop a feasible approach for repairing periodontal bone defects with the in vivo tissue engineering bone incorporated with bioabsorbable PLA membrane and to provide evidences for the clinical application. Osteoinductive HA/β-TCP sintered at 1100°C were implanted in the femur medial muscles in the hind legs of three dogs. Four weeks after implantation, the in vivo tissue engineering (TE) bone was explanted. Meanwhile, artificial periodontal bone defects of 8mm×6mm were performed on the buccal side of 4th premolar and 1st molar of mandible bilaterally, with the exposure of dental roots. The defects were treated as follows: (1) in vivo TE bone and PLA membrane; (2) HA/β-TCP ceramics and PLA membrane; (3) PLA membrane only; (4) empty control. At the 2, 4, 8 weeks post-transplantation, the dogs were sacrificed. The specimen were harvested and evaluated by gross inspection, dental radiography, SPECT (99mTC-MDP) and histological observation by MPIA2500. The results showed that more mature osseointegration was found in the group 1. We presumed that the in vivo TE bone graft could enhance the reparation of periodontal bone defects.
In Vivo Osteogenic Potential of Mesenchymal Stromal Cells Derived from Patient''s Bone Marrow on Hydroxyapatite Ceramics
Authors: Matsushima Asako , Kotobuki Noriko , Machida Hiroko , Morishita Toru , Takakura Yoshinori , Ohgushi Hajime
Published: March 2009

Since 2001, we have started tissue engineered approach for hard tissue repair using mesenchymal stromal cells (MSCs) derived from patient’s bone marrow. MSCs were culture expanded on culture dish, then applied on various ceramics including hydroxyapatite (HA) ceramics. The MSCs on the ceramics were further cultured in osteogenic media to induce osteognenic differentiation. The differentiation resulted in appearance of bone forming osteoblasts as well as bone matrix on the ceramics, thus we could fabricate the tissue engineered bone. We have reported that the tissue engineered bone is effective for treatment of large bone defect, which is difficult to repair only with artificial materials such as HA ceramics. The present study focused on osteogenic capability of cryopreserved human MSCs derived from patients who already were treated by the tissue engineered bone. The MSCs showed high alkaline phosphatase activity together with abundant bone matrix formation when cultured in osteogenic media. The MSCs also showed in vivo new bone formation when implanted at subcutaneous sites of athymic nude rats. Based on the results, we concluded that the tissue engineering approach is a reliable method to be used in hard tissue regeneration.
Mechanical Properties of Living Adherent Cells: Interaction of Cell and Shear Flow
Authors: Liu Xiao Heng , Yu Chang , Zou Min Jun , Yin Hong Mei
Published: March 2009

To investigate the interaction of the adherent cell and shear flow, a compound drop
model was developed to simulate a living adherent cell adhered to a smooth substrate, and a two
dimensional computational fluid dynamics (CFD) was conducted to solve the model equations. The
results showed that the deformability of the cell increases with Reynolds number and initial contact
angle. The nucleus deforms with the cell, and the deformation index of the cell is greater than that
of the nucleus. The cell is more deformable while the nucleus is more capable of resisting external
shear flow. The cell and the nucleus are not able to deform infinitely with the increase of Reynolds
number and the deformation index reaches a maximum. We conclude that the nucleus plays a
particular role in the mechanical properties of the adherent cell.
Comparison on the Osteogenesis Potential between Poly(lactide-Co-Glycolide) and Alginate as Bone Tissue Engineering Scaffold In Vivo
Authors: Li Cai , Chen Run Liang , Liu Lei , Lin Yun Feng , Tian Wei Dong , Li Sheng Wei
Published: March 2009

Poly(lactide-co-glycolide) (PLGA) and alginate(AG) are the most promising scaffolds in the bone tissue engineering for their stable mechanical characters and three-dimensional porous structure. This study aimed to assay the in vivo osteogenesis potentials by loading the autogenous bone marrow stromal cells (BMSCs) on PLGA or AG. The results suggested that PLGA and AG are both ideal bone tissue engineering scaffold. BMSCs/AG has stronger osteogenesis potentials in vivo than BMSCs/PLGA.
Biomechanical Study on Repairing Bone Defect with Composite of Bovine Bone Morphogenetic Protein and Hydroxyapatite
Authors: Wang Hang , Chen Meng Shi , Liu Lei , Tang Wei , Tian Wei Dong
Published: March 2009

To investigate the mechanical property (shear strength, bending strength and compressive strength) and the interface combinative ability of the composite of bovine bone morphogenetic protein (bBMP) and porous hydroxyapatite (HA) with different pore diameter. HA1 (Φ100-300μm) and HA2 (Φ130-500μm) were used as carriers of bBMP(5mg). The 4 types material (HA1, HA2, bBMP /HA1, bBMP /HA2) were implanted into the femur of 10 dogs (2 dogs each group) for the shear test and 15 dogs (3 dogs each group) for the bending test and compressive test. The shear strength of all kinds of materials were increased as time went on and the shear strength of bBMP/HA1 was highest in four materials. The bending strength of bBMP /HA1 was close to the normal femur in the 24th week. The compressive strength of all materials was lower than the cortex of the dog’s femur until 24th week. The compressive strength of bBMP /HA1 was the highest in four types. The compressive strength of HA2 and bBMP /HA2 was decreased after implantation. Implant of bBMP /HA with 100-300μm diameter had strong bonding with the host bone, and had better mechanical properties than that with 130-500μm diameter. So the porous bBMP /HA (Φ100-300 μm ) could be a useful graft material due to its strength.
Effect of Woven Fabric Biodegradable Polyglycolic Acid on Joint Resurfacing with Fresh Chondrocytes in a Rabbit Model
Authors: Shi Zhong Li , Yan Wei Qi , Feng Jie , Guan Bing Gang , Liu Yang Bo , Yan Shi Gui
Published: March 2009

To evaluate the effectiveness of the cell-material in situ on joint resurfacing, a woven
fabric polyglycolic acid (PGA) treated with fresh chondrocytes was used for repairing cartilage
defects. Full-thickness defects were created in the weight-bearing surfaces of the femoral
intercondylar fossa in a rabbit model. The defect was filled with and without PGA under surgical
condition. Before implantation, chondrocytes were co-cultured with PGA for one day. The animals
were sacrificed at eight weeks after implantation and evaluated grossly and histological score.
Morphological examination showed that for PGA/chondrocytes group, the repaired tissue appeared
similar in color and texture to the surrounding articular surface. While for the untreated control, no
cartilage-like tissue was observed at all defects, but connective fibrous tissue. Histological analysis
revealed neochondrogenesis and clusters of cartilage matrix with specific safranin-O staining for the
PGA/cell group. The Gross and histological evaluation indicated a significantly higher score for
PGA/cell group than for PGA and control group. These results suggest that the woven fabric PGA
may facilitate the formation of cartilage tissues by providing a biodegradable and good-handle
vehicle for the delivery to and retention of organized cell matrix constructs in vivo site. It might
therefore enhance neochondrogenesis because of the superior biodegradable and biocompatible of
PGA scaffold sheet, while the more suitable biological environment might sustain cell growth and
in situ cell function, suggesting a promising candidate for functional tissue engineering of clinical
environment.
Lessening Hydroxyapatite Ceramics Particles Adverse Effects by Serum Modification: A Preliminary In Vitro Study and Mechanism Analysis
Authors: Yuan T. , Chen X. N. , Shan J. , Zhang Xing Dong
Published: March 2009

Serum immersion, a new method of pre-treated HA ceramics, has been compared with
SBF immersion and untreated HA particles in cell culture condition. MTT assay indicates that
serum-immersion lessens particles cytotoxity of HA particles in cultured L929 mouse fibroblast cell
(p<0.05). Neither immersion nor traditional physical factors such as particle size, shape should be
responsible for these because SBF immersion with the similar factors results in no significant
improvement. The reason might be serum proteins adsorption and biommetic microstructure
formation on the ceramics surface, which affect cellular membrane behaviors, phagosome
metabolization and cellular protein secretion. Otherwise, cells with particles degraded early
apparently, which indicated that particles influence the cell cycle. The whole processes must be
correlated intensively with cytokine, protease and intracellular ion concentration, which would be
discussed in our follow-up studies.
Effect of Fibrin Sealant on Early Bone Healing with Tooth Ash and Plaster of Paris in Ovariectomized Rats
Authors: Kim S.G. , Kim S.H. , Lim Sung Chul , Bae Chun Sik
Published: March 2009

This study examined the role of tissue adhesives during early healing and the
effects of tooth ash and plaster of Paris on bone healing in the presence of osteoporosis.
Sixty rats were assigned to five groups randomly and each group was further divided
into two subgroups, which were examined 4 and 8 weeks after implantation. Histologic
sections and histomorphometric analysis of defects were obtained 4 and 8 weeks after
surgery. Bone formation was significantly better in the non-ovariectomized groups
compared to the ovariectomized group. A mixture of tooth ash and plaster of Paris is
recommended, but not tissue adhesives, in ovariectomized cases.
Effect of Cyanoacrylate-Based β-TCP Adhesive on Pullout Strength of Orthodontic Mini-Screw
Authors: Lee Sang Bae , Cha Jung Y. , Lee Doug Youn , Park Kyeong Jun , Kim Kyoung Nam , Kim Kwang Mahn
Published: March 2009

In this study, the effect of cyanoacrylate-based β-tricalcium phosphate (β-TCP) on
pullout strength of orthodontic mini-screw was evaluated. New cements were prepared by mixing
Histoacryl® (n-butyl cyanoacrylate) and acid-treated β-tricalcium phosphate. The ratios of β-TCP to
Histoacryl® were 0, 0.5, 1.0, and 2.0. Artificial bone blocks were used as a substrate for the miniscrew
implantation. The test groups were divided into three groups (one solid bone block [group 1]
and a bone block with a 0.9 mm hole [group 2], and a bone block with a 2.5 mm hole [group 3]).
And each group was divided into subgroups according to cement usage and non-usage. The used
artificial bone density was 0.64g/cm2. Pullout strengths were determined using a universal testing
machine. Statistical analysis was performed using the SPSS 9.0 for Windows program. Paired
samples t-tests and ANOVA were used with p<0.05. The maximum pullout strengths were 295.9 ±
3.8 N for group 1, 261.1±15.0 N for group 2, and 273.2±20.0 N for group 3. In group 1 and 2, the
pullout strength in the subgroup using cement was higher than that of the subgroup of not using
cement (p<0.05). In group 3, the pullout strength in the subgroups using cyanoacrylate-based β-
TCP cement was higher than that of the subgroup using conventional glass ionomer cement (GC
Fuji-I, GC Co., Tokyo, Japan) (p<0.05). These results indicate that our β-TCP/Histoacryl® cements
have the potential to enhance pullout strength of the orthodontic mini-screw.
Histologic and Radiographic Evaluation of Progressive Loading on Implants Placed into Extraction Sockets
Authors: Ban Yu , Gong Ping , Wang Shao An , Geng N. , Liu X.G. , Yuan Quan , Zhao J. , Man Yi
Published: March 2009

To evaluate the effects of progressive loading on implants placed into extraction sockets. 4
beagle dogs were extracted bilateral 3rd, 4th and 2nd premolar and immediately inserted the implant
at first surgery (0d), 14d and 21d. Using the newly developed vertical occlusion loading system,
progressive loading procedures were taken 24h after insertion. The vertical bone loss (VBL) and
bone-to-implant contact ratio (BIC) was measured by image analysis software and analyzed using the
paired student t test. After 28d period of healing, each animal was sacrificed and the samples were
evaluated by scanning electron microscopy (SEM). The mean vertical bone loss in control groups
was larger than that of the experimental groups at 14, 21 and 28 day (P<0.05). SEM showed that the
mineralization rate of experimental groups was faster than the control groups. The bone-implant
contact ratios in experimental groups were more than that in the control groups. The differences were
statistically significant (P<0.05). Compared with non-loading implant, progressive loading can
promote osseointegration and decrease vertical bone loss. Progressive loading of implants placed into
extraction sockets can be performed without interfering with the osseointegration process.
Biocompatibility of Calcium Phosphate Ceramics Synthesized from Eggshell
Authors: Oh Nam Sik , Na Yun Ho , Ji S. W. , Song S.W. , Oh S.H. , Lee Sang Jin , Lee Myung Hyun
Published: March 2009

The aim of this paper was the HA and β-TCP powers were synthesized by a new wetchemical
method using eggshell and phosphoric acid. The biocompatibility of synthesized natural
HA, HA/β-TCP(50:50) and β-TCP derived from eggshell was compared with those of as
commercial chemical powder with mesenchymal stem cells derived from human bone marrow.
Development of crystalline phases of the mixtures was studied as functions of mixing ratio and
temperature using X-ray diffractometer. The morphological characteristics of the calcined
eggshell and synthesized powders were examined by scaning electron microscopy. The in-vitro
cytotoxicity and cell attachment of sintered disks were examined using human bone marrowderived
multipotent stem cells(hBMSCs). Cell response was characterized by MTT assay ,
Alkaline phosphatase stain and RT-PCR analysis. Pure HA was synthesized in the mixing ratio of
1:1.1 wt% at 900°C for 1h. the crystallization of HA was started at 800°C in the 1:1.1 mixing
ratio, ant the HA phase was continued up to the high temperatures. In the ratio of 1:1.3 and
1:1.5 wt%, β-TCP was effectively synthesized at 900°C. In the 1:1.5 ratio, β-TCP phase was
detected at 700°C, and complete crystallized β-TCP was observed above 900°C. At the higher
temperature than 1000°C, the β-TCP was gradually decreased and α-TCP was observed. The HA
and β-TCP disk does not exert cytotoxic effect on the hBMSCs undergoing osteoblastic
differentiation. In addition, the hBMSCs are adhered on the surface of synthesized natural HA
and β-TCP disk as successfully as on the culture plate or as commercial chemical HA and β-TCP
disk. The hBMSCs adhered on either synthesized natural HA, β-TCP or as commercial chemical
HA, β-TCP disk displays undistinguishable actin arrangement and cellular phenotypes, indicating
that synthesized natural HA, β-TCP does not disrupt normal cellular responses. Analysis of
differentiation of the hBMSCs cultured on culture plate, synthesized natural HA, β-TCP and as
commercial chemichal HA, β-TCP disk shows that three matrices are able to support osteoblastic
differentiation of the hBMSCs as accessed by alkaline phosphatase staining.
Effect of Precipitation Method on Stoichiometry and Morphology of Hydroxyapatite Nanoparticles
Authors: Shi He Bin , Zhong Hong , Liu Yu , Gu Jin Yan , Yang Chang Sheng
Published: March 2009

This paper reports synthesis of hydroxyapatite nanoparticles by three precipitation
methods. Homogeneous aqueous solution of Ca(NO3)2 and H3PO4 was used as precursor solution,
and NH3•H2O was precipitator. Calcium deficient hydroxyapatite nanorods were obtained by
adding the precipitator into precursor solution, near stoichiometric hydroxyapatite nanoparticles
were derived from adding precursor solution into the precipitator, and smaller hydroxyapatite
nanoparticles were prepared by adding precipitator and precursor solution simultaneously into a
reaction vessel. The stoichiometry of hydroxyapatite was mainly affected by pH at precipitation
reaction process. The crystal size and shape of hydroxyapatite particles was related to Ostwald
ripening. The stoichiometry and morphology of hydroxyapatite nanoparticles can be controllable by
selecting suitable coprecipitation process.
Formation of Apatite Pattern by Electrophoretic Deposition of Apatite Nuclei
Authors: Yamaguchi Seiji , Yabutsuka Takeshi , Hibino Mitsuhiro , Yao Takeshi
Published: March 2009

Resist pattern was developed on a cathode for EPD and a polytetrafluoroethylene (PTFE) film was set on the cathode. Then EPD was performed with a suspension of hydroxyapatite (HA) nuclei in ethanol. In this process, HA nuclei were deposited on a porous PTFE film so as to transcribe the resist pattern. The substrate was soaked in simulated body fluid (SBF) and HA was selectively induced on HA nuclei. As a result, HA pattern whose resolution was as high as the resist pattern was fabficated.
Eearly Bone Repair and Regeneration of Nano-Sized ß-Tricalcium Phosphates/Collagen Composite in Rabbits
Authors: Guan Bing Gang , Yang Di Sheng , Shi Zhong Li , Weng Wen Jian , Yan Wei Qi
Published: March 2009

A novel biomimetic composite consisted of nano β-tricalcium phosphate and collagen
(n-TCP/Col.), having similar structure with the natural bone, was produced by a wet-chemical
method. The biological effect with and without n-TCP/Col on bone repair and regeneration was
evaluated by histological and radiological examination in a rabbit femoral condyle model. The
results showed that radiopacity of implant decreased gradually and began to increase at 12 weeks,
while no obvious changes for the control. Histological results revealed that trabecular bone formed
around the implant at 4 weeks and increased at 8 weeks; By 12 weeks, bone filling with Harvard’s
system was observed around the implant. By contrast, only loose connective tissue was seen in
control group. This was further illuminated by fluorescence microscopy. The results of this study
suggested that the novel nano β-tricalcium phosphate and collagen composite possessed good
properties of osteoconductivity and degradation in the biological environment, which could have
potential application as a promising bone substitute.
Study of The Mechanical Property of Magnetite/ Hydroxyapatite/ Chitosan Nano-Composite
Authors: Wu Jia , Hu Qiao Ling , Chen Fu Ping , Li Bao Qiang , Shen Jia Cong
Published: March 2009

Magnetite/hydroxyapatite/chitosan rods have been prepared via in situ compositing
method. The mechanical properties were characterized and evaluated for suitability as a bone repair
materials. Scanning electron microscopy (SEM) was carried out to investigate the microstructure of
CS/HA/Fe3O4 composite. Effect of inorganic content on the mechanical properties of the
CS/HA/Fe3O4 composite was also investigated. It was observed that the mechanical properties of
the composite in the dry condition improved as the percentage of CS content increased. Mechanical
properties of CS/HA/Fe3O4 composite rod are much better than that prepared via traditional method.
Bending strength, bending modulus of CS/HA/Fe3O4 composite are 118.5 MPa, 2.3 GPa,
respectively. All of these material properties are twice or three times stronger compared with that of
nature bone of human being.
Study on Interface Reaction and Its Control of Titanium Fiber-Hydroxyapatite Composites
Authors: Li Jian , Wang Yu Ling , Huang Yuan , He Fang , Wan Yi Zao
Published: March 2009

Various reinforcements have been used to reinforce hydroxyapatite composites.
Bioactivity of hydroxyapatite and excellent mechanical properties of titanium make titanium fiber
reinforced hydroxyapatite composite a promising biomaterial. In this work, a titanium fiber was
chosen as the reinforcement, and hydroxyapatite powders prepared by wet precipitation method
were used as matrix material. The interface between titanium fiber and hydroxyapatite was
investigated in terms of microstructure and chemical composition using a combination of scanning
electron microscopy (SEM), X-ray diffraction (XRD) and energy disperse spectroscopy (EDS).
Experimental results showed that titanium/hydroxyapatite composite with controllable interface
could be made by choosing proper preparation method.
Fabrication of Porous Titania and Porous Calcium Phosphate Coatings on Titanium Surface
Authors: Feng Bo , Weng Jie , Liang Yu , Qu Shu Xin , Wang Jin , Lu Xiong
Published: March 2009

A network-like porous layer on titanium was prepared by acid-etching with a mixture of
CaCl2 and HCl. The pores ranged from 1 to 10!m. The small pores distributed in big pores. In the
simulated biological environment, porous octacalcium phosphate (OCP) coatings spontaneously
formed on the porous- surfaced titanium. Pre-calcification after acid-etching accelerated OCP
precipitation. The OCP coatings had big pores of about 25!m and small pores of 1~3!m, the latter
distributed in the former at different depth.
A Simplified Preparation Method of Silicon-Substituted Calcium Phosphates According to Green Chemistry Principles
Authors: Dorozhkin Sergey V. , Dorozhkina Elena I. , Oktar Faik N. , Salman S.
Published: March 2009

A simplified preparation method of silicon-substituted calcium phosphates with a very
high yield (close to 100%) has been elaborated, according to the principles of Green Chemistry. The
technique consists of mixing of crystals of calcium nitrate and ammonium dihydrogen phosphate in
the desired proportions, following by addition of the necessary amount of a silicon-containing
compound. The homogenous mixture is sintered between 900 and 1200°C. Either a siliconcontaining
hydroxyapatite (Si-HA) or a silicon-stabilized tricalcium phosphate (Si-αTCP) can be
synthesized, depending on the Ca/P, Ca/(P+Si) and Si/P molar ratios.
Exploring Antibacterial and Antiadhesive Activities of Titanium Surface Modified with Hydroxyapatite Sol-Gel Containing Silver
Authors: Chen W.C. , Bao C.Y. , Jeyachandran Y.L. , Ou Guo Min , Fan Hong Song , Liao Yun Mao , Zhang Xing Dong
Published: March 2009

Circumambient tissues infection is a common complication of implanted percutaneous
and permucosal devices (PDs). In order to counter the infection, the titanium abutment surface of
PDs was modified to achieve antibacterial and antiadhesive activities. Titanium discs were
immersed into hydroxyapatite (HA) sol containing different mass fraction silver and thermally
treated to get modified discs. The modified discs become more smoother and get crystal HA
coatings containing silver. Silver ion release test demonstrate the release rate is very slow and the
coating is a reservoir of silver. The antibacterial and antiadhesive effects of modified discs on
Staphylococcus aureus and Porphyromonas gingivalis were evaluated. Modified titanium discs with
silver significantly inhibited the growth of these two bacteria compared with both the polished
titanium discs control and modified titanium discs without silver. And titanium discs modified with
more silver have higher antibacterial activity and less bacteria adhesion in this study. These findings
indicate that titanium surface modified with the HA sol-gel containing silver could achieve
antibacterial and antiadhesive activities, and the abutments of PDs are promising to be modified by
this method.
Comparisons of the Apatite Presentation and Demineralization in Enamel and Cementum by Atomic Force Microscopy
Authors: Zeng Quan , Zhang Yin Hui , Xing Zhi Hua , Zhao Xiao Jun
Published: March 2009

AFM is used to study tooth surfaces (enamel and cementum) in order to compare the
pattern of particle distribution and demineralization process in the two dissimilar tooth hard tissues.
Our approach is focusing mainly on the qualitative observations of tooth surface morphology and
quantitatively measuring the early stages of mineral loss. The native enamel presented globular
particles tightly packed. After polishing the aprismatic layer, the particles observed were relatively
larger and more organized than ones in the outmost enamel surface. The cementum had small grains
arranged in some degree of ordered packing with varying crystallite orientations. After different time
treatment with citric acid solution, all the sample surfaces became more irregular and had the deeper
grooves. The maximum mineral loss was greatest for the cementum sample and lowest for the native
enamel. The demineralization difference between the enamel and cementum shows the structure and
component play important roles in the morphological changes of demineralization. These
demonstrate that the microstructure and demineralized difference between enamel and cementum
obtained with AFM are complementary to the usual SEM images and TEM data. AFM is suitable for
measuring early stages of tooth surface demineralization.
Calcium Titanate Film-Coating on Titanium with Hydrothermal Treatments
Authors: Kon Masayuki , Sultana Razia , Fujihara Emi , Asaoka Kenzo , Ichikawa Tetsuo
Published: March 2009

Film-coating on the surface of titanium was investigated by hydrothermal treatments with
a maximal pressure of 6.3 MPa (280°C) in CaO solution and water to improve bioactivity and
biocompatibility. As a result, calcium titanate (CaTiO3) film was formed on the titanium surface.
The surface-coated titanium was immersed in a simulated body fluid (SBF) to estimate its
bioactivity. Apatite precipitation was observed on all hydrothermal-treated titanium surfaces after
immersion in SBF for 4 weeks. In particular, the apatite precipitation of titanium treated with 6.3
MPa in CaO solution was clearer and larger in amount than those of all other hydrothermal-treated
specimens. The results suggest that surface modification of titanium with high-pressure
hydrothermal treatments can be expected to improve bioactivity and biocompatibility.
Preparation of Silicate Substituted Calcium Deficient Hydroxyapatite by Coprecipitation
Authors: Shi He Bin , Zhong Hong , Liu Yu , Zhang Feng Zhao , Liang Ming Chuan , Chen Ming
Published: March 2009

This paper presents a typical coprecipitation method to synthesize silicate-substituted
calcium deficient hydroxyapatite (SiCDHA). A homogeneous aqueous solution of Ca(NO3)2• 4H2O,
H3PO4 and Si(CH3CH2O)4 (TEOS) was used as precursor, and NH3 aqueous solution as precipitator.
A series of samples were prepared by adding the precipitator to the precursor then following a general
coprecipitation route. The results showed that the so-prepared samples were SiCDHA. SiCDHA was
thermal unstable and decomposed to tricalcium phosphate and wollastonite-like phase. These new
phases were helpful to improve the bioactivity of sintered SiCDHA ceramics.