bluuebunny/crossref_metadata_2025 huggingface dataset:
A High Notch Toughness Agglomerated Flux for Submerged Arc Welding of Pipeline Steel
Authors: Ren De Liang , Liao Bo , Xu Changling , Hu Lianhai , Xiao Fu Ren
Published: March 2009

By using the mathematical uniform design, a new agglomerated flux for high speed and multi-arc submerged arc welding (SAW) has been developed in this paper, which performs excellently in welding process, and the effects of flux composition on the welding characteristics is analyzed as well. The mechanical tests show that the weld metal obtained in SAW with this flux exhibits high toughness at low temperature, and the other mechanical properties of the weld metal also satisfy the technical specifications for the West to East Pipeline Project in China. The microstructures of the weld metal are also examined. Both optical and TEM microphotoes demonstrate that the weld consists mainly of small-sized and uniformly distributed acicular ferrite. These microstructures can effectively prevent the initiation and propagation of micro cracks, resulting in high notch toughness of the weld metal at low temperature.
Three-Dimensional Stress Analysis by Three-dimensional Local Hybrid Method
Authors: Machida Kenji
Published: March 2009

In the displacement measurement inside a specimen by speckle photography, it is not easy to get clear Young's fringes images. Stress-intensity factors of mixed mode can be estimated by embedded speckle photography. However, the error of the stress intensity factor inside a specimen was considerably large. To evaluate the 3-D stress field inside the specimen from displacement data on the free surface obtained from the 2-D intelligent hybrid method, we developed the 3-D local hybrid method based on an inverse problem analysis. The accuracy of the 3-D local hybrid method varies depending on the depth of the plane of error assessment, hybrid domain size, and specimen thickness. Hence the optimal analysis conditions were discussed.
Buckling Analysis of Shells with a Circumferential Crack
Authors: Putra I.S. , Dirgantara T. , Firmansyah  , Mora M.
Published: March 2009

In this paper, buckling analysis of cylindrical shells with a circumferential crack is
presented. The analyses were performed both numerically using FEM and experimentally. The numerical analyses and experiments were conducted for several crack lengths and radius of curvature, and two different boundary conditions were applied, i.e. simply support and clamp in all sides. The results show the effect of the presence of crack to the critical buckling load of the shells. There are good agreements between experimental and numerical results.
A Study on Relationship between Hardness and Hydrostatic Stress
Authors: Lee Jong Il , Choi Young , Boo Kwang Suck , Park Joon Hong
Published: March 2009

Hardness is most likely to mean the resistance to indentation, and to the design engineer it often means an easily measured and specified quantity which indicates something about the strength and heat treatment of the metal. Especially, Vickers hardness is one of the most widely useful methods to obtain mechanical properties of a product. Firstly, in this study, a method to estimate hardness will be presented using FE simulations of Vickers hardness tests from the viewpoint that hardness indicates resistance to plastic deformation. To verify our method, the results of the
simulations for several materials such as commercial aluminum alloy and steel will be compared with those of Vickers hardness tests for the materials. Secondly in this study, hardness numbers of the several materials will be obtained as a function of hydrostatic stress. Through the results of this study, the estimation of hardness number of a specific material will be very easy to obtain and access even though the material is under a kind of hydrostatic stress state.
Finite Element Analysis of the Repeated Braking with 3-D Coupled Model
Authors: Hwang Jung Ho , Kim Heung Seob , Choi Young , Lee Seong Beom , Kang Ki Weon
Published: March 2009

In automotive applications, a particular area of concern is the relation between thermoelastically induced hot spots and noise and vibration in brake system. The finite element methods have been extensively used for thermal analysis applied to brake components. The two-dimensional model has been extended to an annular three-dimensional disc model in order to consider more realistic braking condition. In a conventional braking analysis, the interface pressure is assumed either constant or inversely proportional to radius. However, under the dynamic braking conditions, the frictional heat generated during braking causes thermoelastic distortion that modifies the contact pressure distribution. This paper describes the thermo-elastic instability arising from friction heat generation in braking and proposes the finite element methods to predict the variation of temperature and thermal deformation under single braking and repeated braking mode.
Time and Frequency Domains Iterative Regularization for Inverse Analysis of an Instrumented One-Point Bend Specimen
Authors: Gunawan Fergyanto E. , Homma Hiroomi , Kanto Yasuhiro
Published: March 2009

This paper proposes an application of the inverse analysis to estimate the elastic
response ahead of the crack-tip of a one-point bend specimen. The difficulty of the problem lies on determination of the impulse response function that relates the elastic response to a unit applied impact force which is numerically ill-posed. Two iterative numerical regularization schemes are proposed, first is a time-domain regularization based on the conjugate-gradient method and second is a frequency-domain regularization based on an optimal filter approach. Both schemes are evaluated by using the data obtained from an impact experiment. The result shows that the estimation error is about 18.0%.
Shape Design Optimization of the Boom System in High Ladder Vehicle
Authors: Kim Hong Gun , Kim Yoo Shin , Yang Sung Mo , Hong D.P. , Nah S.C. , Yang G.E. , Lee H.K.
Published: March 2009

A shape design optimization of the boom system in high ladder vehicle modeled by
3-dimensional finite elements is carried out. The structural analysis is performed using 3-D FEA (Finite Element Analysis) giving the results of displacements, stresses and natural frequencies. The section height and width of the boom is controlled by the FEA result data. The subproblem approximation method is implemented for the optimal shape based on displacement and principal stress. In the meantime, Lanzcos algorithm method is implemented in order to find the natural
frequency of the system. The optimal models obtained by three different optimization processes are compared with the initial model and evaluated for economic conditions respectively. It is found that the different shape optimization processes give the different shape optimization results, which suggest their unique optimal shapes under their necessary design condition.
Simulation of Deformation Behavior of Polymeric Materials by Chain Network Model
Authors: Shinozaki Akira , Kishimoto Kikuo , Inoue Hirotsugu
Published: March 2009

The mechanical properties of polymers are strongly influenced by meso-scale (10-9~10-3 m) structure such as entanglement, molecular weight distribution, orientation, etc. It is important to understand the relationship between the mechanical properties of polymeric material and meso-scale structure. Some studies related to the relationship have been made. However detail of the relationship is still unclear. Especially, the studies emphasize on entanglement and branch are few. This study aims to clear the role of entanglement and branch for mechanical properties by simulating the meso-scale structure using 3D network models. In the models, there are two structures considered. One of them has no branch, and, others have branch. Large strain deformation of network models is evolved via improved molecular dynamics analysis.
A Viscoelastic Model for an Automotive Transmission Rubber Mount
Authors: Lee Seong Beom , Kim Heung Seob , Hur Shin , Kim Wan Doo , Woo Chang Su , Park Chan Seok
Published: March 2009

An automotive transmission (TM) rubber mount is a device that is used in automotive systems to cushion the loads transmitted from the vehicle body structure. A TM rubber mount is used to support the engine in the vertical direction. However, the dynamic behavior of loaded rubber mount is not yet known to a reasonable degree of accuracy. The relationship between the force applied to a TM rubber mount and the resulting deformation exhibits features of viscoelasticity. Therefore, in this study, viscoelastic properties were measured during ramp-toconstant displacement control tests. A force-displacement relationship for a TM rubber mount is important for multi-body dynamic numerical simulations. Hence, an explicit force-displacement relationship was developed and expressed in terms of a force relaxation function. A method that can be used to determine the force-displacement relationship from experimental data for a TM rubber mount was also developed. Solutions were obtained and the results were compared with experimentally measured force-displacement behavior. The predictions of the proposed forcedisplacement relationship were in very good agreement with the experimental results.
Application of X-Ray Micro-Computed Tomography on Macroporous Calcium Phosphate Glass Scaffolds
Authors: Kim Min Chul , Lee Byung Hyun , Kim Kyoung Nam , Kim Kwang Mahn , Choi Seong Ho , Kim Chong Kwan , LeGeros Racquel Z. , Lee Yong Keun
Published: March 2009

A numerous techniques have been applied to fabricate three-dimensional scaffolds of high porosity and surface area. And X-ray micro computed tomography can be used studying the architecture of scaffold. In this study, we fabricated three-dimensional macroporous scaffold by polymeric sponge method using calcium phosphate glass. Calcium phosphate glass slurry was prepared by dissolving the glass powder in water polyvinyl alcohol, polyethylene glycol and dimethyl
formamide. Reticulated polyurethane sponges were used as a template and were coated with the prepared slurry by infiltration technique several times. Sintering at 950oC exhibited dense microstructure as well as entire elimination of organic additives. By repeating the coating and sintering process, it was possible to decrease the pore size and be thick the strut of the structure. The
unique feature of the micro computed tomography is that the three dimensions computed reconstruction can be sliced along any direction to gain accurate information on the internal geometric properties and structural parameters of scaffold. Porosity, surface area per unit volume and mean thickness of strut were evaluated through imaging and computer software of scaffold scan data.
Preparation of Bioactive Cellulose/Hydroxyapatite Composite Tapes
Authors: Müller Frank A. , Lessnau Kristina , Müller Lenka , Rauch Marcus W. , Zollfrank Cordt , Greil Peter
Published: March 2009

A composite material consisting of cellulose and HAp was prepared using coagulation of a native cellulose suspension. Composite tapes with a HAp content below 50 vol.% exhibit a gradient of filler particles across the cross-section of the sample due to gravity force that causes sedimentation of HAp, as long as the viscosity of the suspension is below a critical level during the coagulation
process. According to gravimetric and solution analysis as well as SEM, the filler content influences the amount and uniformity of HCA precipitated in the surface of the tape. With increasing content of filler in the cellulose matrix, the apatite growth from SBF is promoted, due to a higher amount of HAp particles that serve as nucleation sites.
Confocal Raman Spectroscopic Analysis of Ceramic Hip Joints
Authors: Pezzotti Giuseppe , Clarke Ian C. , Jobe C. , Donaldson T. , Yamamoto Kengo , Tateiwa Toshiyuki , Kumakura T. , Tsukamoto R. , Ikeda Junji
Published: March 2009

A survey of confocal Raman/fluorescence microprobe spectroscopic techniques is presented with emphasis placed on surface analysis of artificial hip joints. Suitable instrumental configurations are first explained in
some details in order to describe the versatility of the spectroscopic microprobes to biomedical materials analyses. Then, these notions, which represent the foundation for structural and mechanical analyses of joint surfaces, are applied to selected cases of paramount importance in hip arthroplasty.
The Characteristics of the New Ceramic Material for Artificial Joints
Authors: Nakanishi Takefumi , Shikata Kunihide , Wang Yu Cong , Iwamoto Mikio , Kondo Makoto
Published: March 2009

A new zirconia-toughened alumina ceramic (JMM-ZTA) for a ceramic-on-ceramic hip replacement has been developed. The JMM-ZTA has a fracture toughness superior to zirconia, and the JMM-ZTA/JMM-ZTA combination has superior wear-resistant performance to alumina/alumina. Moreover, the JMM-ZTA shows an excellent crystalline phase stability. Therefore, the JMM-ZTA is believed to be useful for artificial hip prostheses.
Statistical Analysis of Surface and Sub-Surface Residual Stress Fields in Retrieved Alumina Femoral Heads after Long-Term Implantation
Authors: Tateiwa Toshiyuki , Yamamoto Kengo , Kumakura T. , Variola F. , Pezzotti Giuseppe , Gaspera O.D. , Falcone G. , Sakakura S. , Clarke Ian C.
Published: March 2009

The surface of retrieved alumina (Al2O3) femoral heads was investigated by piezo-spectroscopic techniques based on confocal photo-stimulated fluorescence. The micrometric spatial resolution of the laser beam impinging on the investigated joint surface (typically about 1 $m in lateral resolution) enabled us estimating patterns and magnitude of residual stress in extremely narrow zones, at least
comparable with the grain size of the material. According to a statistical collection of data on a microscopic level, it was possible to assess the retrieved femoral heads in-toto, thus extending the microscopic analysis to the entire surface of the joint. A stress field was found, which mainly arose from loading history, and displacements acting on the femoral head during its lifetime. Residual stress data enabled us to draw interesting conclusions about the role of the material microstructure
and the peculiar kinetic mechanisms involved with the use of the joint. Spectroscopic techniques, which are complementary to in vitro testing procedures and theoretical stress analyses based on finite-element methods, can be very useful in improving the design of the femoral head and in optimizing the microstructural characteristics of the ceramic materials employed.
A Simulated Synovial Fluid for Wear Characterization of Artificial Hip Joints by a Hip Joint Simulator
Authors: Takadama Hiroaki , Mizuno Mineo
Published: March 2009

The calf serum solution was defined as the international standard lubricant for wear
characterization of artificial hip joints. It is, however, known that its composition varies according to age, manufacturing processes or production areas of bovine cattle, and that the difference in composition has large effect on the wear characterization. It was difficult to compare the results
obtained by different laboratories. Therefore, it is desirable to develop an artificial lubricant whose composition can be always set to a specified value as an alternative to bovine serum. In the present study, the effect of each major constituent in bovine serum on wear property was studied by hip simulator. As a result, transparent and stable lubricant solutions were prepared. It showed quite similar wear property to bovine serum by controlling the composition. These results serve as a guide
to propose the new lubricant suitable for the wear characterization of hip joint.
In Vivo Evaluation of Porous Hydroxyapatite/Poly D/L-lactide Composite for Bone Substitutes and Scaffolds
Authors: Hasegawa Shin , Tamura Jiro , Neo Masashi , Fujibayashi Shunsuke , Goto Koji , Shikinami Yasuo , Okazaki Kenshi , Nakamura Takashi
Published: March 2009

We had investigated the biocompatibility, osteoconductivity, and biodegradability of a
porous composite of hydroxyapatite (HA) and poly-DL-lactide (PDLLA) implanted into rabbit femoral condyles. It showed excellent osteoconductivity and biodegradability as a bone substitute. Newly formed bones were remodeled, and materials were resorbed almost completely at 78weeks
after implantation. In consideration of its biocompatibility and degradability, we investigated its potential for use as a cellular scaffold and evaluated its osteoinductive property. On implantation to the rat dorsal subcutaneous tissue loaded with syngeneic bone marrow cells, osteogenesis with
enchondral ossification was seen both on and in the material at 3 weeks after implantation. This osteogenesis in the HA/PDLLA tended to get mature and newly formed bone tissues were found in the material by 6weeks. To investigate the osteoinductive property material itself has, we attempted to
implant this porous composite material to extra-osseous canine dorsal muscle. At 2months, osteogenesis was seen in the pores of the material. It indicated the material induced osteogenesis with intramembranous ossification process. Therefore, HA/PDLLA might be a desirable material for bone
substitutes and cellar scaffolds with osteoconductive and osteoinductive property.
Enhanced Osteoinductivity of Porous Titanium Implant by Sodium Removal
Authors: Takemoto Mitsuru , Fujibayashi Shunsuke , Matsushita Tomiharu , Suzuki J. , Kokubo Tadashi , Nakamura Takashi
Published: March 2009

The aim of this study was to optimize the surface treatment and to accelerate the
osteoinductivity of porous bioactive titanium implant. Previous studies have reported that sodium removal with hot water treatment converts sodium titanate on the surface of an alkali-treated titanium plate into titania with a specific structure, which has better bioactivity than sodium titanate. We developed a dilute hydrochloric acid (HCl) treatment for porous titanium, which removed sodium from the complexly shaped porous structure more effectively than conventional hot water
treatment. Three types of surface treatments were applied: (a) alkali and heat treatment, (b) alkali, hot water, and heat treatment (conventional treatment), and (c) alkali, dilute HCl, hot water, and heat treatment (Na-free treatment). The osteoinductivity of the materials implanted in the back
muscles of adult beagle dogs was examined at three, six, and twelve months. Na-free porous bioactive titanium exhibited the highest osteoinductivity, and bone formation was observed within three months. This study showed that sodium removal has a significant positive effect on the osteoinductivity of the porous bioactive titanium implant.
Safety of Ceramic Components
Authors: Merkert Patricie , Krause Christoph , Kuntz Meinhard , Dietrich Martin
Published: March 2009

A statistical analysis of ceramic implant failure is presented. It is shown that the majority of failures occure within the first 12 months after implantation. From this characteristic distribution the prediction of the total failure rate is possible even for the latest years of production. There have been considerable improvements of the reliability in the past 5 years. Furthermore, there is evidence
that the failure rate strongly depends on ball head diameter. For the largest ceramic ball head of 36mm diameter up to now no failure has been reported. From these results it is concluded that ceramic implant failure is in general released by individual circumstances. In particular, the probability of failure may be strongly increased in the case of limited mobility and an increased risk of impingement. In the case of a well developed specific surgeon training and right choice of the
ceramic implant system the ceramic components provide an extremely reliable and safe solution for the patient.
Effect of Hydroxyapatite Interposed Between Bone and Bone Cement in Total Hip Arthroplasty on Long Term Longevity ----19 to 20 Year Radiographic Studies on Using and Without Using of HA in the Same Patients----
Authors: Kim Seok Cheol , Oonishi Hironobu , Inoue Hiroko , Fujita Hiroshi , Doiguchi Yuichi , Oomamiuda Koichi
Published: March 2009

THAs were performed with conventional cementing on one side (1985 to 1986) and with modified cementing using HA granules on the other side (1986) of the same patients. Both hips were compared 19 to 20 years after surgery. In IBBC, there was no loosening, radiolucent line (RLL) < 1 mm was in one acetabulum and osteolysis was in one femur. In conventional cementing three hips were revised within 18 years in five acetabular loosenings. RLL > 2 mm and osteolysis were defined in every patients in both femur and acetabulaum.
Effects of Mixture of Fibrin-Fibronectin Sealant System and Calcium Carbonate in Periodontal Intrabony Defects
Authors: Jung Ui Won , Chang S.J. , Choi Seong Ho , Kim C.S. , Chai Jung Kiu
Published: March 2009

This study evaluated the effects of mixture of fibrin-fibronectin sealant system(FFSS) and calcium carbonate(CC) in periodontal intrabony defects. Thirty six sites with two or three wall intrabony defect were used. 14 defects treated with periodontal flap surgery were assigned as the control group. 11 defects treated with CC implantation were designed as experimental group 1 and 11
defects, treated with CC and FFSS implantation as experimental group 2. The control and experimental groups all achieved statistically significant improvements in probing depth and clinical attachment level from the baseline (P<0.01). In mean postsurgery probing depth and gingival recession reduction, there were no statiscally significant differences between the experimental groups
and the controls. However, mean postsurgery clinical attachment levels of both experimental groups improved significantly more than that of the controls. As a result, we suggest that mixture of FFSS and CC can be used effectively in intrabony defect as osteoconductive materials.
Influence of Alginate on Precipitation of Calcium Phosphates
Authors: Lima Daniel O. de , Prado da Silva Marcelo Henrique , de Campos Jose B. , Rossi Antonella M. , Beppu Marisa Masumi
Published: March 2009

Calcium phosphates are widely used in medicine and dentistry. However, synthesis of these substances through precipitation methods still presents problems regarding reproducibility. Alginate is a polymer extracted from brown algae, whose monomers are D-mannuronic and L-guluronic acids, and is suitable for biomedical applications. The aim of this paper is to investigate how the poly-ionic nature of alginate affects phase composition of calcium phosphate obtained through a precipitation method.
Dissolution Behavior of Submicron Biphasic Tricalcium Phosphate Powders
Authors: Wang Rui Bing , Weng Wen Jian , Deng Xu Liang , Cheng Kui , Liu Xing Gang , Du Pi Yi , Shen Ge , Han Gao Rong
Published: March 2009

Submicron α-tricalcium phosphate (α-TCP), β-tricalcium phosphate (β-TCP) and biphasic α/β-TCP powders were prepared by an amorphous calcium phosphate (ACP) precursor way. For the biphasic TCP powders, primary particle size was 300nm, α-TCP and β-TCP primary particles were homogeneously mixed in the submicron powders. When the TCP powders were soaked in acetate buffer solution with pH 5, the Ca ion concentration in the soaked solutions and the resulting morphology variations were measured and observed. The results showed that the dissolution behavior of the biphasic TCP powders was different from α-TCP and β-TCP, and had a higher dissolved Ca ion concentration. This is attributed to a high supersaturation which is cased by the distribution homogeneity of two phase primary particles in submicron powders. These demonstrate the biphasic TCP to have potential to extend biological applications of Ca phosphates.
Self-Setting Paste Model in Bioactive Glass Systems
Authors: Lee Y.W. , Kim Hyun Min , Lee Su Young , Kwak J. , Kim Yong Nam , Shin Hyun Gyu , Lee Hee Soo
Published: March 2009

Self-setting paste model in bioactive glass systems was investigated. Particulate glasses based on the systems CaO-SiO2-P2O5 and Na2O-CaO-SiO2 were combined with sodium phosphate solution to constitute paste models. Setting behavior of these pastes, i.e., workability and setting within 30 min were obtained by controlled composition-mass conditions. Specifically, it was found that the setting behavior could be controlled by glass compositions as well as mixing ratios of solids and solutions. These suggest new concept of bioactive cement for various biomedical applications.
In Vitro Bioactivity Characterization of Machinable Glass Ceramics Containing 85wt% Na-mica and 15wt% Fluorapatite
Authors: Göller Gültekin , Akin Ipek , Kahraman A. , Demirkesen Erdem , Urgen M.
Published: March 2009

In this study; in-vitro bioactivity characterization of machinable glass-ceramics having 85 wt% sodium mica (NaMg3AlSi3O10F2) and 15 wt% fluoroapatite has been carried out. Two different heat treatment procedures are applied to the machinable glass-ceramics. The first one is nucleation at 610°C for 2 hours and crystallization at 1000°C for 3 hours and the second is nucleation at 610°C
for 2 hours and crystallization at 1000°C for 4 hours. It is observed that increasing the crystallization time to 4 hours resulted in the increasing the formation of hydroxyapatite layer on surface. According to the microstructural investigations, the morphology of the precipitated crystals are different. In addition, the speed of the precipitation of hydroxyapatite is higher in glass-ceramic B than A. Thin film XRD analysis supports these results.
Preparation and In Vitro Behavior of Bioactive Glasses from Bovine Waste Resource
Authors: Ahn S.H. , Kim Yong Nam , Shin Hyun Gyu , Lee Hee Soo , Hwang Jong Hee , Kim Hyun Min , Kwak J.
Published: March 2009

Preparation of bioactive glasses was attempted utilizing waste bovine as raw resource. Bioactive and biodegradable batch compositions in the Na2O-CaO-SiO2 system were included with calcined bovine, whose phase was high-purity oxy-hydroxyapatite. Bovine inclusion as large as 40 mass% was shown to present highly bioactive glasses; bovine in the bioactive and biodegradable
compositions presented glasses with controlled bioactivity and biodegradability, respectively. These indicate not only a plenty biological resource of bio-interactive materials, but also an alternative strategy for bioactive glasses with multi-functional applications.
Comparison of Antibacterial Effect of Three Bioactive Glasses
Authors: Zhang Di , Munukka Eveliina , Leppäranta Outi , Hupa Leena , Ylänen Heimo O. , Salonen Jukka I. , Eerola Erkki , Viljanen Matti K. , Hupa Mikko
Published: March 2009

Antibacterial effects of three powdered bioactive glasses were compared by measuring the pH of the simulated body fluid in immediate contact with the glass powder particles and by cultivating four microorganisms in the powder-solution mixtures. After individual cultivation with the microorganisms the bioactive glasses showed ability to kill bacteria, but the effects were very dependent on glass composition and on the microorganism as well as on cultivation time. The
results indicated that antimicrobial property of bioactive glasses correlates with their ability to change the pH of the body fluid in immediate contact with the glass. However, the increase in pH is not the only factor influencing the antimicrobial properties.
Evaluation of Bovine Bone Ash Particles for Tooth-Bearing Bone Defect Healing
Authors: Kang H.J. , Cho M.J. , Lim J.H. , Kwon D.K. , Lee J.M. , Shin Hong In
Published: March 2009

Osteogenic repair is highly dependant upon the substrate carrier or matrix. As a part of the effort to develop a suitable scaffold optimizing bone regeneration, we evaluated the efficiency of bovine bone ash particles, prepared by ashing at 600 °C for 8 hrs and pulverizing to 150-250 µm size particles, as a scaffold for bone tissue regeneration. The non-cytotoxic bovine bone ash particles, evaluated by Agar over lay test, showed no disturbance in cellular proliferation and
osteogenic differentiation in an in vitro cell culture system. Furthermore, the implanted bone ash particles in artificial bone defects on rat mandible revealed favorable biocompatibility and regeneration of bone and dentin associated with bone ash particles. The new bone and reparative dentin were well integrated with bone ash particles. These findings suggest that allogenic bone ash
particles composed mainly of hydroxyapatite are applicable for repair of tooth related bone defects as well as pulp damaged tooth repair.
In Vitro Bioactivity of Hydrogen Peroxide Modified Titanium: Effects of Surface Morphology and Film Thickness
Authors: Wu Jin Ming , Wang Min , Hayakawa Satoshi , Tsuru Kanji , Osaka Akiyoshi
Published: March 2009

Anatase films with various morphologies were formed on Ti surface through different
approaches using hydrogen peroxide solutions. A porous anatase surface was found to favor apatite deposition in SBF, or in vitro bioactivity. Thicker films with wider crack gaps also showed enhanced in vitro bioactivity. However, the most predominant effect was the abundance of Ti-OH functional groups incorporated in the anatase films.
Preparation of Silica-Doped Poly(Lactic Acid) Composite Hollow Spheres Containing Calcium Carbonates
Authors: Miura Noriko , Maeda Hirotaka , Kasuga Toshihiro
Published: March 2009

Silica-doped poly(lactic acid) (PLA) composite hollow spheres containing calcium carbonates (Si-CCPC spheres) were prepared using aminopropyltriethoxysilane (APTES) for injectable bone fillers combined with a cell-delivery system. Si-CCPC spheres have a hollow spherical shape of ~1 mm in the external diameter and an open channel in the shell, which is selfformed.
The channel size is about 500 *m in diameter. X-ray energy dispersive spectroscopy (EDS) analysis showed incorporation of silicon in Si-CCPC spheres. After soaking Si-CCPC spheres in simulated body fluid (SBF), hydroxycarbonate apatite formed on the Si-CCPC spheres. Inductively
coupled plasma atomic emission spectroscopy (ICP-AES) showed that the Si4+ ion is released from Si-CCPC spheres in SBF.
Osteoblast-Like Cell Behaviors on Non-Woven Silica Fabric
Authors: Hwang Mina , Yoon Hanna , Lee Yong Keun , Lim Bum Soon , Rhee Sang Hoon
Published: March 2009

The biological activity of osteoblast-like MC3T3-E1 cells on the newly developed
non-woven silica fabric was investigated. The attachment, proliferation, and differentiation of osteoblast-like MC3T3-E1 cells were evaluated by MTS and alkaline phosphatase activity assays, respectively. The non-woven silica fabric showed higher biological activities than those of tissue culture plates with regard to attachment and proliferation while there was no significant difference
with respect to differentiation. These results suggest that the non-woven silica fabric has a potential application as a bone grafting materia
An Economic Method for Chitosan Production
Authors: Peker Ismail , Oktar Faik N. , Senol Murat , Eroglu M.
Published: March 2009

Chitosan is a deacetylated derivative of chitin, which is a naturally abundant
mucopolysaccharide, supporting the matter of crustaceans, insects, and fungi. Because of its unique properties, such as non-toxicity, biodegradability, and biocompatibility, chitosan has a wide range of applications in various fields. Increasing interest on chitosan’s usage has resulted in high consumption. Therefore, production of chitosan from essential sources with desired characteristics
has become an important issue. Several methods, with different chemicals and reaction conditions, have been reported in the literature. This study aimed to shed light in several features of a very promising chitin isolation method described by Tolaimate et al. and its effect on the produced chitosan’s phisico-chemical characteristics.
Preparation of a Bioactive Poly(ε-Caprolactone) Triol/Silica Composite
Authors: Rhee Sang Hoon , Lee Yong Keun , Lim Bum Soon
Published: March 2009

Effect of poly(ε-caprolactone) structure on the mechanical properties and apatite-forming ability of poly(ε-caprolactone)/silica composite was investigated. Star-shaped poly(ε-caprolactone) was used in the experiment and it was end-capped with 3-isocyanopropyl triethoxysilane following the reaction with tetraethyl orthosilicate by sol-gel method. It was heat-treated at 150 oC for 24 hours
and then tensile mechanical and dynamic viscoelastic testings were conducted, respectively. Its bioactivity was evaluated by the apatite forming ability in simulated body fluid at 36.5 oC. Its tensile strength was about 22 MPa while elastic modulus was about 2.6 GPa when the content of poly(ε-caprolactone) was 60 wt.%. The formation of apatite crystals on its surface was confirmed after 1 week of soaking in the SBF. The high elastic modulus of this composite was explained in terms
of its 3-dimensional network structure.
Properties of Calcium Phosphate Powder Prepared from Phosphoryl Oligosaccharides of Calcium
Authors: Umeda Tomohiro , Itatani Kiyoshi , Mochizuki Hiroko , Davies Ian J. , Musha Yoshiro , Koda Seiichiro
Published: March 2009

The phosphoryl oligosaccharides of calcium (POC), extracted from potato starch, are composed of phosphorus oligosaccharides and calcium ions. Ultrafine calcium phosphate particles, whose main phase was hydroxyapatite (Ca10(PO4)6(OH)2: HAp), could be prepared through the hydrothermal treatment of POC solution at a temperature between 110 and 130°C; X-ray diffraction
indicated the crystallinity of HAp in the resulting powder to be poor and similar to that of living bone. The present HAp powder was regarded to be calcium deficient carbonate apatite with the OH- group being partly substituted by a carbonate (CO3
2-) group. The solubility of the resulting powder in dilute hydrochloric acid was higher compared to that of commercially available HAp, suggesting
excellent bioabsorbability for the present powder.
Nanostructured Apatite Coatings for Rapid Bone Repair
Authors: Thian E.S. , Huang Jie , Best Serena , Barber Zoe H. , Bonfield William
Published: March 2009

Nanostructured hydroxyapatite (nHA) thin coatings of thickness 0.5 µm have been successfully produced using a radio-frequency magnetron sputtering technique, through careful selection and control of the processing conditions. nHA coatings were immersed in simulated body fluid (SBF) to
determine the rate of nucleation and growth of an apatite layer on their surface. A dense, newlyformed apatite layer with similar characteristics to that of the biological bone apatite, was observed after 7 days of immersion in SBF. X-ray diffraction and infrared analyses confirmed this layer to be
calcium-deficient nanocrystalline carbonate HA. All these results demonstrated that the novel nHA coatings were highly bioactive, and the time-frame required to form a dense apatite layer was reduced significantly as compared to the micrometer-sized, sintered HA pellets (from 28 days to 7 days).
Remineralization Potential of New Toothpaste Containing Nano-Hydroxyapatite
Authors: Jeong S. H. , Jang S.O. , Kim Kyoung Nam , Kwon H.K. , Park Yong Duk , Kim B.I.
Published: March 2009

Hydroxyapatite is the main component of enamel that gives the tooth a bright white appearance and eliminates the diffused reflection of light by filling up the fine pores of the tooth surface. Accordingly, remineralization of the teeth can be expected to some extent if hydroxyapatite is used to treat an incipient caries lesion (early white spot lesion). In addition, the remineralization effect will be increased if the particle size of hydroxyapatite can be reduced to less than that of the micron-size in existing toothpaste preparations. The aim of this in vitro study was to evaluate the effect of nano-hydroxyapatite toothpaste, which was produced by nano-technology, on the remineralization of human enamel. A tooth specimen, on which artificial incipient caries had been induced, was immersed into two toothpaste slurries for remineralization. One contains nano-sized hydroxyapatite and fluoride, and the other contains nano-sized hydroxyapatite excluding fluoride. In order to evaluate the remineralization effect, the Vickers Hardness Number & SEM image of the enamel surface was evaluated at each step. There were significant differences in VHN values between those obtained before and after the remineralization steps. The results showed that the remineralization effect increased with increasing immersing time (P<0.05). However, there were no significant differences in VHN values between the two groups (P>0.05). SEM also demonstrated differences the in micro surface at each step. In conclusion, a toothpaste containing nano-sized hydroxyapatite has the potential to remineralize an incipient caries lesion. In addition, the addition of fluoride had no synergistic effect on remineralization.
Sol-Gel Synthetic Model of Bi-Structured Bioactive Nano-Hybrids in TEOS-PDMS System
Authors: Lee Kang Yong , Lee Y.H. , Kim Hyun Min , Kwak J. , Lee H.K.
Published: March 2009

Ceramic-polymer bi-structured nano-hybrid, in which the bioactive silicate surface is nano-hybridized with flexible polymeric bulk, was synthesized in the tetraethoxysilane (TEOS)-polydimethylsiloxane (PDMS) sol-gel system. Different solutions for surface and bulk, whose compositions of TEOS: PDMS were respectively fixed 100: 0 and varied from 50: 50 to 20: 80 with various molecular weight (Mw) of PDMS, were subjected to lamination and controlled polymerization and condensation process, producing a large transparent crack-free monolithic bulk. Characterizations at near-surface cross-section of the bi-structured hybrids revealed that typical bioactive silicate was combined with all types of bulk hybrids regardless of their PDMS contents and Mw without distinct interface, indicating possibility of a novel bioactive nano-composite with enhanced physical and biological functions.
Novel Method for Hydroxyapatite Coating by Hydrothermal Hot-Pressing via Double Layered Capsule
Authors: Onoki Takamasa , Hashida Toshiyuki
Published: March 2009

A new hydrothermal method is proposed which enables us to prepare thin hydroxyapatite (HA) ceramic coatings on Ti substrates with a curved surface at low temperatures. The method uses double layered capsules in order to produce a suitable hydrothermal condition; the inner capsule encapsulates the coating materials and a Ti substrate, and the outer capsule is subjected to isostatic pressing under the hydrothermal condition. In this study, it is demonstrated that a pure HA ceramic layer with the thickness of 50 µm could be coated to a Ti cylindrical rod at
the low temperature as low as 135°C under the confining pressure of 40 MPa. Pull-out tests were conducted to obtain an estimate for the adhesion properties of the HA coating prepared by the double layered capsule method. The shear strength obtained from the pull-out tests was in the range of 4.0-5.5 MPa. It was also shown that the crack propagation occurred within the HA coating layer,
not along the HA/Ti interface in the pull-out tests.
The Effect of Cell Behavior on Plasma Sprayed HA Coatings with Different Post Treatment
Authors: Cao Y. , Lin Qiang , Tang Min , Ying X.Q. , Pang Su Juan , Yang B.B. , Zhang Z.T. , Chen Ji Yong , Zhang Xing Dong
Published: March 2009

The initial interactions of plasma-sprayed HA coating surface with osteoblasts was investigated. Two kind of post-treatment methods were been used for HA coating: (1) Heated in air at 650oC for 30 min, (2) Heated in water vapor at 125oC, 0.15Mpa for 6 hours. The third passage rabbit osteoblasts were cultured on the HA coating plates for 24 h. The results showed: The lower dissolution rate and more surface hydroxyl groups (OH-1) group in the HA coating resulted in greater numbers of adhered osteoblasts and higher cell activity, The post-water vapor treated HA coating have better biological behavior in vitro.
Human Osteoclasts Behaviour on Sol-Gel Derived Carbonate Hydroxyapatite Coatings on Anodized Titanium Alloy Substrates
Authors: Ramaswamy Y. , Ben-Nissan Besim , Roest R. , Haynes D. , Zreiqat Hala
Published: March 2009

Titanium alloy has been used as a material for orthopaedic implants, however drawbacks still exist. Considerable efforts have been taken to modify the surface structure of the implant material and improve the biological performance. Previously we have demonstrated that biomaterials surface modification has a significant effect on the regulation of osteogenesis. We have investigated the behaviour of human osteoclasts on sol-gel coated carbonated hydroxyapatite on anodized titanium alloy. Osteoclasts cultured on the modified surface were able to attach and spread, exhibiting the characteristic peripheral brush border. Successful differentiation of the monocytes into osteoclasts and their attachment to the coated surface and the formation of resorption-like imprints indicated that carbonate hydroxyapatite (CHAP) coated titanium alloy play a significant role in regulating the functional activity of osteoclasts.
Resorbable Gypsum Coating on Calcium Metaphosphate for Controlled Degradation Rate
Authors: You Chang Kuk , Tadjiev Timur R. , Shin Hong In , Kim Kyo Han , Park Eui Kyun , Kim Shin Yoon , Jeong Jae Ho , Kim Suk Young
Published: March 2009

Five kinds of gypsums, (1) CaSO4•2H2O (caldium sulfate dihydrate; CSD), (2) CaSO4•1/2H2O (calcium sulfate hemihydrate; CSH), (3) CaSO4 (calcium sulfate anhydrite; CSA), (4) CSH200 (CSH heat-treated at 200°C after self-hardening), and (5) CSH600 (CSH heat-treated at 600°C after self-hardening) were used as candidates for coating materials on calcium metaphosphate (CMP) scaffod to control degradation rate of CMP and to extend degradation limit. The disks of CSD, CSH, CSA, CSH 200, and CSH600 were prepared by self-hardening after mixing with water, where CSH200 and CSH600 were heat-treated at 200°C and 600°C, respectively. In order to control fast resorption rate of gypsum, CMP-CSA composites were prepared with different CSA contents such as 0, 5, 10, 20, 30, 50, and 70 vol% and heat-treated at 900°C for 4 hours. The degradation rates of various gypsums were evaluated in revised simulated body fluid (r-SBF) for 1, 3, 7, and 21 days, respectively. Degradation rate of each specimen was measured in terms of weight loss change with time and degraded surface morphology was examined by SEM. All kinds of gypsums were transformd into CSD after self-hardening with water. Most of gypsums were degraded by 35~60 wt% at 7 days and by 70~99 wt% at 21 days of soaking in SBF. In the group of CMP-CSA composites, the degree of degradation of them was considerably retarded compared to that of five pure gypsums. The surface morphology showed elongated needle-like crystals during the degradation with time.
Bioactive Bone Cements Containing Micron-Sized Titania Particles
Authors: Goto Koji , Hashimoto Masami , Takadama Hiroaki , Tamura Jiro , Fujibayashi Shunsuke , Hasegawa Shin , Kawanabe Keiichi , Kokubo Tadashi , Nakamura Takashi
Published: March 2009

Three types of polymethylmethacrylate (PMMA)-based composite cements containing 40− 56 wt% micron-sized titania (titanium oxide) particles, designated ST2-40c, ST2-50c, and ST2-56c, were developed as bone substitutes for vertebroplasty, and evaluated for their mechanical, setting, and
biological properties. In animal experiments, ST2-50c and ST2-56c were implanted into rat tibiae and solidified in situ. Their biological properties were evaluated at 6 and 12 weeks after implantation. Compressive strength, bending strength, and bending modulus increased with increasing titania content. Peak temperature during the setting reaction decreased as the filler content increased. ST2-56c had direct contact with bone over larger areas than ST2-50c at 6 and 12 weeks. Data from the present study indicated that ST2-56c is a good candidate as a bone substitute
for vertebroplasty.
Bioactive PMMA-Based Cement Incorporated with Nano-Sized Rutile Particles
Authors: Hashimoto Masami , Takadama Hiroaki , Mizuno Mineo , Kokubo Tadashi , Goto Koji , Nakamura Takashi
Published: March 2009

Bioactive bone cement with mechanical properties higher than that of commercial polymethylmethacrylate (PMMA) bone cement are strongly desired to be developed. In the present study, PMMA-based cement incorporated with nano-sized rutile particles was prepared. The PMMA-based cement (rutile content was 50 wt%) shows the compressive strength (136 MPa) higher than that of commercial PMMA bone cement (88 MPa). The hardened cement formed apatite on the surface in a simulated body fluid within 3 days. Therefore, this PMMA-based cement incorporated with rutile particles might be useful as cement for fixation of prostheses as well as self-setting bone substitutes, because of its high apatite forming ability and mechanical strength.
In Vitro Bioactivity of Injectable Ceramic Orthopaedic Cements
Authors: Faris Adam , Engqvist Hakan , Lööf Jesper , Ottosson Mikael , Hermansson Leif
Published: March 2009

The objective of this paper is to investigate and compare the in vitro bioactivity of three injectable cements for orthopaedic applications.
The cements were all based on chemically bonded ceramics technology; calcium phosphate (Norian SRS), and experimental versions of calcium silicate and calcium aluminate cements. The cements were mixed with their respective liquids and were after setting stored in phosphate buffered
saline at 37 °C for time periods of 1h, 24 h, 7 days and 30 days. After storage the samples were analysed with scanning electron microscopy (SEM), thin film X-Ray diffraction (TF-XRD) and energy dispersive spectroscopy (EDS) for the presence of possible apatite on the sample surface. The SEM and EDX analyses showed that surface films containing Ca and P (along with the
other atoms present in the materials) were formed on all materials. Thus reactions with the storage medium had occurred. The TF-XRD analysis confirmed the presence of apatite for the calcium phosphate cement and the calcium aluminate cement. On the calcium silicate cement most of the surface zone seemed to be amorphous with only broad peaks corresponding to apatite. Thus all the
tested materials showed signs of in vitro bioactivity.
Investigation into Carboxylic Acids as Cement Reactants
Authors: Lilley K.J. , Gbureck Uwe , Wright Adrian J. , Farrar David , Barralet J.E.
Published: March 2009

Bajpai et al. originally reported the formation of cements by the mixture of carboxylic acids and β-tricalcium phosphate (β-TCP). In the current study, we report and contrast four such cement systems formed from mixing citric, malic, 2-oxoglutaric or phosphoric acid with β-TCP. Cements formed from malic or 2-oxoglutaric appeared to contain crystalline phases and were determined to contain brushite, β-TCP and unreacted acid. In contrast, cement formed with citric acid was poorly
crystalline, containing little evidence of brushite formation and was unstable in water and therefore does not appear to be a feasible cement system.
Investigation on Self-Emerged Porous CPC Containing Chinese Medicine
Authors: Liu Y.R. , Qu Shao Xing , Cheng H.F. , Li Xiao Hong , Zhou S.B. , Li M.H. , Huang C. , Tan R. , Xiong L.L. , Feng Bo , Weng Jie
Published: March 2009

In this study, biodegradable poly-lactic-acid (PLA) microspheres encapsulated with Salvia Miltiorrhiza Bunge (SMB), ranged from 100µm to 300µm, were prepared by a solvent evaporation method. Those PLA microspheres mixed with CPC powder, at a mass fraction of 0.2 to 0.8, to yield a self-emerged porous CPC. The surface morphology of PLA microspheres and CPC
were observed by optical microscopy and scanning electron microscopy (SEM), respectively. The function groups of PLA microspheres and the phase composition of CPC were analyzed by Fourier transform infrared spectrometer (FTIR) and X-ray diffraction (XRD) , respectively. A preliminary study of drug release was performed by immersing PLA microspheres and CPC into simulated body
fluid (SBF) for a various interval points. And the concentrations of SMB in SBF were measured by UV-VIS spectroscopy. The present results showed that the self-emerged porous CPC containing Chinese medicine could be prepared by adding biodegradable PLA microspheres. PLA microspheres can promote the CPC aqueous reaction to form final product, hydroxyapatite (HA).