bluuebunny/crossref_metadata_2025 huggingface dataset:
Differences of Bone Regeneration by Various Calcium Phosphate/Collagen Composites
Authors: Kamakura Shinji , Sasaki Kazuo , Honda Yoshitomo , Masuda Taisuke , Anada Takahisa , Kawai Tadashi , Matsui Aritsune , Matsui Keiko , Echigo Seishi , Suzuki Osamu
Published: March 2009

Our previous studies showed that synthetic octacalcium phosphate (OCP) enhances bone
regeneration more than hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP). Also, a synthetic
bone substitute constructed of synthetic octacalcium phosphate (OCP) and porcine atelocollagen
sponge (OCP/Col) showed stable bone regeneration. The present study was designed to investigate
the difference of bone regeneration by OCP/Col and other calcium phosphate-collagen composites.
OCP/Col, β-TCP$-collagen% composite (β-TCP/Col), or HA$-collagen% composite (HA/Col) sponge
was prepared from pepsin-digested atelocollagen isolated from the porcine dermis and OCP, β-TCP,
or HA granules, respectively. A standardized critical-sized defect was made in the rat calvarium, and
various calcium phosphate-collagen composites were implanted into the defect. The rats were fixed
at four weeks after implantation and radiographic and histological examinations were performed by
undecalcified cross sections of implants. Radiographic examination showed that uniform radiopaque
masses were observed in the created defects treated with OCP/Col, whereas granulous and foggy
radiopacity was observed in β-TCP/Col and HA/Col. Histological examination showed that newly
formed bone was observed in the reticulum of OCP/Col and around the implanted OCP. The
regenerated bone by β-TCP/Col or HA/Col seemed to be less than that by OCP/Col and would not to
be nucleated by the granules of β-TCP or HA. The present study indicated that bone regeneration by
OCP/Col was different from those of β-TCP/Col and HA/Col. Application of OCP/Col would be
expected for clinical use in the future.
Valuation of Ceramic Explants after 19 Years In Vivo
Authors: Oberbach Thomas , Begand Sabine , Glien Wilfried
Published: March 2009

Ceramic hip joint heads are used in the field of endoprosthetics for more than 30 years.
There are a lot of in vitro tests to determine the behaviour of these implants under body like conditions
that means hip simulator testing etc. But it is accepted, that these tests can only reflect ideal
conditions in vivo. Therefore it is necessary to examine also retrievals after different periods in
vivo. Six explanted ceramic heads after times in vivo between 0.5 and 19 years were investigated
concerning their geometrical dimensions and surface conditions.
16 to 21 Year Clinical Results of Total Hip Arthroplasty with HA Granules at Cement-Bone Interface (Interface Bioactive Bone Cement)
Authors: Oonishi Hironobu , Oonishi Jr. Hiroyuki , Kim Sok Chol , Ohashi Hirotsugu , Ojima Satoshi
Published: March 2009

To augment cement-bone bonding, hydroxyapatite (HA) granules were interposed at cement-bone
interface (IBBC technique). HA granules were smeared on the bone surface just before cementing
components. Porous HA granules of 300 to 500μm in diameter and 100 to 300μm in diameter were used
from 1986 to 1988(first generation) and 1989 to 1991(second generation), respectively. 222 hips of 151
patients in the first generation and 252 hips of 170 patients in second generation could be followed. After 16
to 21 year follow up, radiolucent line (space), less than 1mm, was observed in 4 hips(1.8%) in the first
generation and in 15 hips(6.2%) in the second generation(p<0.01). osteolysis was observed in 1 hip(0.5%)
and 6 hips (1.6%), respectively. Loosening (separation) was observed only 2 cups (0.8%) in the second
generation.
Clinical Results for 19 to 21 Years on Total Hip Prosthesis with Ceramic Head Combined with UHMWPE Socket
Authors: Oonishi Jr. Hiroyuki , Oonishi Hironobu , Kim Sok Chol , Masuda Shingo , Ueno Masaru , Ohashi Hirotsugu
Published: March 2009

In total hip prosthesis (THP), we have been using alumina ceramic femoral heads to reduce
polyethylene debris and the modified cementing technique, which was named “interface bioactive
bone cement (IBBC)” method to improve implant fixation. In this study, we investigated the
long-term clinical performance of THPs with an alumina ceramic head and IBBC method. From 1986
to 1988, 285 joints (215 patients) were operated on by a senior surgeon, and 265 joints (192 patients)
could be followed up. The presence of radiolucent lines, loosening, osteolysis and
ultrahigh-molecular-weight polyethylene (UHMWPE) socket wear were observed. In IBBC, a
radiolucent line appeared as a ’space’, and loosening appeared as a ’separation’ between the HA layer
and the cement. A ‘space’ appeared in 3 joints (1.4%) on the acetabulum and in 4 joints (1.8%) on the
femur, while a ‘separation’ appeared in 3 joints (1.4%) on the acetabulum. Osteolysis was noted in 1
joint (0.5%) on the acetabulum and in 2 joints (0.9%) on the femur. No revision surgery was required.
In our previous study, we reported that the thickness of the socket affected its clinical wear rate and
that the wear rate of sockets with an alumina ceramic head was 20% lower than that of sockets with a
metal head. By reducing wear debris through the use of ceramic heads, osteolysis could be reduced.
Long-term fixation of THPs to the bone has been achieved by using IBBC. Thus, the long-term
clinical results of THPs with an alumina head that were fixed using IBBC were excellent.
Surface Characteristics of HA and β-TCP Immersed in SBF
Authors: Kosachan Nudthakarn , Jaroenworaluck Angkhana , Koolpreechanun Narissa , Jinawath Supatra , Stevens R.
Published: March 2009

Bioactivity of biomaterials is recognized to be of importance and the behavior of
nanosized HA and β-TCP particles is described and compared. The study focuses on the influence
of the phase transformation and grain size on the reprecipitation of calcium phosphate and the
effect of immersion time in SBF on the surface characteristics of the samples. The HA and β-TCP
samples were fabricated by mixing the powders in a ball mill, drying, uniaxial pressing and
sintering at 1150oC for 240 minute using fixed heating and cooling rates. The densified samples
were then immersed in a simulated body fluid (SBF) for controlled periods of time in order to
investigate their bioactivities. Changes in the surface structure were examined to investigate and
characterize phase formation and the chemical functionality of the samples.
Increased Osteoblast Proliferation on Hydroxyapatite Thin Coatings Produced by Right Angle Magnetron Sputtering
Authors: Hong Zhen , Mello Alexandre , Yoshida Tomohiko , Luan Lan , Stern Paula H. , Rossi Antonella M. , Ellis Donald E. , Ketterson J.B.
Published: March 2009

Crystalline hydroxyapatite thin coatings have been prepared using a novel opposing RF magnetron sputtering approach at room temperature. X-ray diffraction (XRD) analysis shows that all the principal peaks are attributable to HA, and the as-deposited HA coatings are made up of crystallites in the size range of 50-100nm. Fourier transform infrared spectroscopy (FTIR) studies reveal the existence of phosphate, carbonate and hydroxyl groups, suggesting that HA coatings are highly crystalline. To study the biocompatibility of these coatings, murine osteoblast cells were seeded onto various substrates. Cell density counts using fluorescence microscopy show that the best osteoblast proliferation is achieved on an HA RAMS-coated titanium substrate. These experiments demonstrate that RAMS is a promising coating technique for biomedical applications.
Crystallographic Changes of Bioceramic Composition of Cadever Bone on Heat Treatments
Authors: Sridhar T.M. , Praveen R. , Shanmugaraj S. , Srinivas S.K. , Das D.
Published: March 2009

Bone is a complicated heterogeneous, viscoelastic, anisotropic material. Its properties
depend on the nature of mechanical forces in addition to the location as well as the age, sex and race
of the subject. Human humerus bones retrieved from cadavers were selected and separated in to
cortical and cancellous parts. They were heat treated at different temperatures 400°C, 600°C and
800°C respectively to study the crystalline nature and composition of cortical and cancellous region
of the humerus bone separately. Hydroxyapatite (HAP) was present as the major phase in the bone
powders at 600 and 800°C with well resolved peaks along with other mineral phases of calcium
phosphate. No amorphous phases were present indicating that the crystal structure of calcium
phosphate compounds is present in crystalline form. FTIR studies further confirm the presence of
phosphate vibrational modes of the entire bone mineral along with the presence of carbonates and
hydroxyl groups.
The Effect of Sodium Dopants on Calcium Polyphosphate Biomaterials
Authors: Ue Judy , Pilliar R.M. , Kandel R.A. , Coyle Tom W. , Grynpas M.D.
Published: March 2009

Sodium-doped CPP was synthesized using three dopant sources (sodium carbonate,
sodium hydroxide and sodium phosphate). These materials were analyzed by XRD to determine
phase composition and by differential thermal analysis to identify phase transition temperatures.
Sintering of resulting glass powders showed that both dopant source and dopant concentration
affects sinter neck formation and crystallinity. The open porosity of sodium phosphate and sodium
carbonate doped samples at 0.1 Na2O/CaO sintered at different temperatures changed significantly.
Crystallization of the construct during sintering was noted at temperatures lower than expected.
Controlling the Reactivity of Calcium Phosphate Cements
Authors: Bohner Marc , Brunner Tobias J. , Stark Wendelin J.
Published: March 2009

The effect of composition on the reactivity of a calcium phosphate cement (CPC) made of tricalcium phosphate (TCP) – water mixtures was investigated by isothermal calorimetry at 37°C. The parameters of interest were the mean particle size of the powder, the use of small amounts of nanosized hydroxyapatite powder, and the phosphate concentration and the pH of the aqueous solution. The results could be well explained by theoretical considerations. The main parameter controlling CPC reactivity was TCP particle size.
Effect of Storage Conditions Prior to Mixing of β-TCP Based Bone Cement on the Reaction Products and the Setting
Authors: Lee Sun Ae , Chung Tai Joo , Lee Kee Ahn , Kim Hyun Min , Oh Kyung Sik
Published: March 2009

β-tricalcium phosphate (β-TCP) based cement features unique biodegradability and mild temperature rise as a material for bone reconstruction. However, the bone cement often raises a shelf life issue and therefore study was made focusing on the temperature and humidity during storage. With the increase of storing days, the density and compressive strength of hardened cement were found to drastically decrease for the cement powder stored in a mixed state. In addition, the setting property was finally lost at the same time. Such a degradation was more evident at higher temperature and was the result of the formation of dicalcium phosphate anhydrous (DCP) instead of dicalcium phosphate dehydrate (DCPD) during the storage. On the contrary, for the cement stored in an unmixed state, very slight changes were detected in density, compressive strength and setting time with the increase of storing days even if the powders were kept in a humid environment. In the unmixed ones, DCP was not precipitated regardless of the storing temperature. Discussion was made on the condition for precipitating either DCPD or DCP in terms of the amount of water supplied during setting. Practically the work suggested that the β-TCP based cement needs to be conserved at lower temperature and in dry environment as possible to effectively increase the shelf life.
Macro/Microporous Biphasic Calcium Phosphate Cylinders and Resorbable Collagen Membranes for Guided Bone Growth
Authors: Fellah Borhane H. , Kimakhe Said , Daculsi G. , Layrolle Pierre
Published: March 2009

This study aims at evaluating bone growth in critical-sized femoral defects of rats filled
with macro micro porous biphasic calcium phosphate ceramic (MBCP) cylinders surrounded or not
by a resorbable collagen membrane. Femoral defects left empty (control) exhibited partial bone
ingrowths after 3 and 6 weeks and were completely healed at 12 weeks. The defects filled with the
collagen membranes appeared partially healed suggesting that the membranes constraint bone
ingrowth. Bone formation occurred around the collagen membrane which partially degraded over
time. In the MBCP/membrane group, bone has grown inside the macro pores of the MBCP
cylinders. Bone ingrowth was more rapid and abundant in the defects filled with MBCP alone. The
combination MBCP/collagen membrane may be beneficial for the reconstruction of large bone
defects without using repetitive surgeries and autologous bone grafting.
Apatite-Forming Ability of Organic-Inorganic Hybrids Prepared from Calcium Silicate and Glucomannan
Authors: Morita Yasuyuki , Miyazaki Toshiki , Ishida Eiichi , Ohtsuki Chikara
Published: March 2009

So-called bioactive ceramics are used for bone-repairing owing to attractive features
such as direct bone-bonding in living body. However, there is limitation on clinical applications due
to their inappropriate mechanical properties performances such as higher brittleness and lower
fracture toughness than natural bone. To overcome this problem, hybrid materials have been
developed by modification of calcium silicate, that is basic component of bioactive ceramics, with
organic polymer. It is known that bioactive ceramics bond to bone through bone-like apatite layer
which is formed on their surfaces by chemical reaction with body fluid. We attempted preparation
of bioactive organic-inorganic hybrids from Glucomannan that is a kind of complex polysaccharide,
and calcium silicate. Hybrids were prepared from glucomannan and tetraethoxysilane (TEOS).
They were treated with 1M (=mol·m-3) CaCl2 aqueous solution for 24 hours. Then ability of apatite
formation on the hybrids was examined in vitro using simulated body fluid (SBF, Kokubo solution).
Surface structure of the specimens was examined by thin-film X-ray diffraction (TF-XRD),
scanning electron microscopic (SEM) observation. The hybrids with TEOS:Glucomannan= 1:1 to
4:1 in mass ratio formed the apatite in SBF within 3 or 7 d, when they were previously treated with
CaCl2 solution.
Osseointegration of Calcium Phosphate Nanofilms on Titanium Alloy Implants
Authors: Paz M.D. , Chiussi Stefano , González Pio , Serra Julia , León Betty , Alava J.I. , Güemes I. , Sanchez-Margallo F.M.
Published: March 2009

In the present work two different hydroxyapatite nanofilms (50 and 100 nm thick) have
been successfully deposited on titanium implants that were previously laser macrostructured in
order to assess the influence of the thickness of nanometric calcium phosphate coatings on the
osseointegration. Cylindrical implants were tested in a sheep tibia model together with titanium
alloy controls achieving very good osseointegration results. Laser macrostructured titanium alloy
implants have shown improved bone regeneration when coated with nanometric films of carbonated
HA. The pulsed laser deposited nanofilm has promoted bone in-growth deep into the laser ablated
craters. There were no significant differences between the two coating thicknesses, neither when
assessed with electron microscopy or classical optical methods. This result suggests that the 50 nm
coating is as effective as the 100 nm one, therefore implying that the thickness limit for such a
bioactive layer to stimulate bone growth may be even further below.
In Vitro Dissolution Behavior of Custom Made CaP Scaffolds for Bone Tissue Engineering
Authors: Impens Saartje , Schelstraete Roosmarijn , Mullens Steven , Thijs Ivo , Luyten Jan , Schrooten Jan
Published: March 2009

The degradation rate of custom made calcium phosphate scaffolds, designed for bone
tissue engineering applications, influences the healing process of critical size bone defects. An
optimal degradation rate exists at which the neo-formed bone replaces the CaP (calcium phosphate)
scaffold [1]. Consequently investigating the complex degradation behavior (dissolution,
reprecipitation, osteoclast activity) of custom made CaP structures gains interest. In this work
different in vitro dissolution experiments were performed to study the degradation behavior of 4 by
composition different calcium phosphates. Ideally these experiments should have a predictive power
regarding the in vivo degradation behavior.
In vitro dissolution tests still lack standardization. Therefore this study focuses on the influence
of two dissolution constraints: (i) the material’s macrostructure (porous - dense), (ii) the regenerated
fluid flow (bath shaking - perfusion). From 4 different CaP compositions porous structures and as a
reference dense disks were produced, using the same starting powder and heat treatment. To
compare the different dissolution tests, all data was normalized to the CaP surface area.
Results show that besides the structural appearances of the CaP structures, also the design of the
dissolution test influences the in vitro dissolution behavior. Moreover there is a need to take the
morphology of the dissolved material into account. The CaP perfusion tests show dissolution
dynamics that resemble the in vivo reality more closely than the shaking bath experiments.
Protein Adsorption Properties of Hydrothermally Prepared Hydroxyapatite
Authors: Kawachi Giichiro , Watanabe T. , Kikukta K. , Ohtsuki Chikara
Published: March 2009

Micrometer-sized hydroxyapatite (HA) with rod-shape was prepared to investigate protein adsorption onto its crystal face, through hydrothermal processing. Adsorption of Bovine serum albumin (BSA) and Lysozyme from chicken egg white (LSZ) on rod-shaped HA crystals with approximately 50 μm in length and 1 μm thickness was examined in phosphate buffer solution. The amount of adsorbed BSA was decreased with increasing phosphate concentration in the examined solution. Adsorption of LSZ was increased with increasing phosphate concentration in the buffer solution up to 50 mmol/L (mM), while it was remarkably decreased when the phosphate concentration reached approximately 100 mM. These phenomena lead to understanding of chromatographic characters of HA for separation of acidic and basic proteins.
Nanostructured Calcium Phosphate Coating for Stents
Authors: Lembke U. , Lange Regina , Beck Ulrich , Neumann Hans Georg
Published: March 2009

A nanoporous calcium phosphate (CaP) coating on metallic surfaces is presented. The
coating consists of a stack of (a) a TiNbN layer deposited by physical vapor deposition and acting
as diffusion barrier against allergenic ions, (b) a SiO2 xerogel layer providing good adhesion
properties and designing the nanoporosity of the outer CaP layer (c) precipitated electrochemically.
SEM results verified a homogeneous nanoscale porous structure of the CaP coating. It is
characterized by a high adhesion strength. If applied to stent covering the nanoporous CaP coating
has promising properties to initiate rapid endothelium formation and reduced risk of restenosis.
Ti Alloy Surface Modifications and Coatings: An Update
Authors: LeGeros John P. , Wang Jin Long , Garofalo Edwin , Salgado T. , LeGeros Racquel Z.
Published: March 2009

Since 1952 when Branemark first reported osseointegration of titanium (Ti) with bone, many academic and industrial research activities have endeavored to improve the efficacy of Ti or Ti alloy (Ti6Al4V) by modifying the chemistry, topography and design of the implant surface. Strong bonding between implant and host tissue minimize the micromovements that promote fibrous tissue formation at the implant interface that may lead to implant failure. Surface design include lateral holes perpendicular to the implant axis, grooves, variations of spacings between ridges, etc. Physico-mechanical means of surface modification is by grit-blasting with various abrasives (alumina, silica, apatitic abrasive), laser ablation, spark discharge, etc. Chemical modifications include: acid etching, treatment with alkali, treatment with fluoride, coating with titanium or with calcium phosphate (by plasma spray, electromagnetic sputtering, electrochemical deposition). A review of studies on Ti or Ti alloy implants with different surfaces showed the following methods to enhance osseointegration and greater bone formation: (1) grit-blasting with apatitic abrasive; (2) acid-etching with mixed acids; (3) adjusting plasma-spray parameter to get a higher HA/ACP ratio in the coating; (4) employing electrochemical deposition (with pulse modulation) or precipitation to obtain thin coating with homogeneous composition; and/or (5) Ftreatment.
Alkali-Modified Titanium Surface Stimulating Formation of Bone-Implant Interface
Authors: Strnad J. , Macháček Jan , Strnad Z. , Povýšil C. , Strnadová Marie
Published: March 2009

This study was carried out to assess the bone response to alkali-modified titanium
implant surface (Bio surface), using histomorphometric investigation on an animal model. The
mean net contribution of the Bio surface to the increase in bone implant contact (BIC) with
reference to the turned, machined surface was evaluated at 7.94 % (BIC/week), within the first five
weeks of healing. The contribution was expressed as the difference in the osseointegration rates (
BIC/'healing time) between the implants with alkali modified surface (Bio surface) and those with
turned, machined surface. The surface characteristics that differed between the implant surfaces, i.e.
surface morphology, specific surface area, contact angle, hydroxylation/hydration, may represent
factors that influence the rate of osseointegration.
Ageing and Fatigue Behaviour of Surface Treated Y-TZP Dental Ceramics
Authors: Kosmač Tomaž , Oblak Cedomir
Published: March 2009

The effects of dental grinding and sandblasting on ageing and fatigue behaviour of
pressure less sintered biomedical grade Y-TZP ceramics were investigated. Disc-shaped specimens
were sintered to high density for subsequent surface treatment and testing. Accelerated aging
experiments by autoclaving in artificial saliva were performed under isothermal conditions at
1340C. The amount of monoclinic zirconia in the ground and sandblasted specimens was < 5% and
about 15 %, respectively and the corresponding strength values were 920 MPa and 1290 MPa. After
autoclaving for 24 hours, the amount of transformed monoclinic zirconia in as-sintered material was
increased to 15 %, resulting in about 10% strength reduction. In contrast, no strength reduction was
observed with the ground and sandblasted specimens subjected to prolonged ageing. At any ageing
condition, the highest survival rate during mechanical fatigue testing was observed with the
sandblasted samples and the lowest with the ground samples. The strength of the surviving
specimens tested in air corresponded well to the mean flexural strength of the particular group
before fatigue testing, whereas lower survival strength values and a larger variability in strength
were obtained with specimens that were subjected to prolonged accelerated ageing prior to
mechanical fatigue testing in artificial saliva.
Solid State MAS-NMR and FTIR Study of Barium Containing Alumino-Silicate Glasses
Authors: Wang Fei , Stamboulis Artemis , Holland D. , Matsuya Shigeki , Takeuchi Akari
Published: March 2009

The glass based on a 1.5SiO2-Al2O3-0.5P2O5-CaO-0.67CaF2 composition was produced and substituted gradually by barium. The structure of the glasses was studied by multinuclear Magic Angle Spinning Nuclear Magnetic Resonance (MAS-NMR) and Fourier Transform Infrared Spectroscopy (FTIR). It was indicated by 29Si and 31P MAS-NMR spectra that silicon was present as Q4 (4Al) and Q3 (3Al) species and phosphorus was in a Q1 pyrophosphate environment. 29Al MAS-NMR spectra showed that four fold coordinated aluminum Al (IV) was the dominant species with a second peak assigned to octahedral aluminum Al (VI). The 19F spectra suggested that the barium addition caused the formation of Al-F-Ba(n) and F-Ba(n) species. Furthermore, a distribution of silicate network including Si-O-Si stretching (Q4 and Q3) and Si-O-[NBO] (Q3) per SiO4 was reflected by the FTIR study.
Comparison of the Physical Properties of Dental Restorative Materials Used in Endodontics
Authors: Watanabe T. , Ando Kimitoshi , Ito T. , Kitamura Naritaka , Nakata Kazuhiko , Tsuruta Shozo , Kawai Tatsushi , Nakamura Hiroshi
Published: March 2009

There is little information concerning the physical properties of various commercialized water-based temporary filling materials. In this study, the setting characteristics of 5 water-based temporary filling cements, i.e., Caviton, HY-seal, Lumicon, Cavit-G, and Cavit-W, were examined. Reinforced plastic pipes were filled with the test materials, and the specimens were then immersed in distilled water at 37°C. Setting time of each specimen was determined by a penetration test using a Vicat penetrometer; and setting layer depth was measured with micrometer calipers. Cavit-W exhibited the fastest setting time, whereas Caviton and HY-seal demonstrated the slowest setting time. These results indicate that the setting properties of these materials used in this study were significantly different for each material, which showed some changes on the surface and the internal part after the start of water absorption.
Studying Dental Ceramic-Bioactive Glass Composites
Authors: Kontonasaki Eleana , Kantiranis Nikolaos , Chatzistavrou Xanthippi , Papadopoulou Lambrini , Paraskevopoulos Konstantinos M. , Koidis Petros
Published: March 2009

Dental ceramic-bioactive glass composites support the attachment and proliferation of
human periodontal ligament cells, while their immersion in a simulated body fluid (SBF) results in
the precipitation of biological hydroxyapatite further supporting cell proliferation [1]. The aim of
the present study was the comparative evaluation of three dental ceramic-bioactive glass
composites’ crystal structure relative to bioactive glass amount and the evaluation of their
bioactivity. All composites consisted of leucite and Na2CaSi3O9 crystals dispersed in amorphous
glassy matrix. Leucite and Na2CaSi3O9 crystals decreased significantly in all composites with the
highest amount of dental ceramic, which did not precipitated apatite during the examined
immersion time in SBF. An increase of Na2CaSi3O9 crystals in the composites with the highest
amount of bioactive glass resulted in faster apatite formation. Increased bioactivity was linearly
correlated to increased amount of bioactive glass.
Evaluation of Bone Ingrowth in Free Form Fabricated Scaffolds
Authors: Adolfsson Erik , Malmström Johan , Thomsen Peter
Published: March 2009

Colloidal processing was used to cast zirconia and hydroxyapatite materials. The cast
materials reached densities around 99% when sintered at 1500°C and 1200°C respectively. By
controlling the colloidal process the sintered density of hydroxyapatite was also reduced to around
80% when the same sintering condition was used. The casting process was combined with free form
fabrication to prepare designed scaffolds with identical macroporosity. These scaffolds were used to
evaluate the early bone tissue response in rabbit femur. After six weeks of implantation the bone
area in scaffolds of zirconia and hydroxyapatite were compared. In scaffolds of hydroxyapatite the
bone area was roughly three times larger compared to corresponding scaffolds of zirconia. When
the scaffolds of hydroxyapatite also contained an open microporosity of around 20% the amount of
bone was even more pronounced. The results showed the importance of the material composition
and the microstructure on the bone regenerating performance of scaffolds.
Chitosan Pyruvic Acid Derivatives: Preparation, Moisture Absorption-Retention Ability and Antioxidative Activity
Authors: Yuan W. , Yin Xue Qiong , Tu W.P. , Lin Qiang , Cao Y.
Published: March 2009

Chitosan pyruvic acid derivatives was successfully prepared from chitosan and pyruvic
acid under reducing conditions, via aldimine formation. The chemical structure of the derivatives
was proved by 13C NMR and IR. It was found ratio between glucose residues and pyruvic acid,
reaction time, pH, and molecular weight of original chitosan had great influence on the degree of
substitution (DS). N-(1-carboxyethyl) chitosan (N-CE-CTS) showed similar moisture
absorption-retention curve and ability with HA, and much better ability than the original chitosan.
Hydroxyl radical scavenging ratio of 4g/L chitosan and N-CE-CTS was 35.0% and 41.7%,
respectively.
Rearrangeable Nonblocking 8×8 Matrix Optical Switches Based on Extended Banyan Network
Authors: Zha Ying , Sun De Gui , Liu Tie Gen , Zhang Ying , Li Xiao Qi , Jiang Jun Feng
Published: March 2009

Based on the CROSSBAR network (CN) and the BANYAN network (BN), two new rearrangeable nonblocking constructions of extended BANYAN network (EBN) are proposed for implementing 8×8 optical matrix switch. The interconnection characteristics of these two types of rearrangeable nonblocking EBN were studied, and the logic program for driving switching units was provided. The calculated insertion loss was 3.3 dB for 8×8 optical matrix switch. Silica waveguide 8×8 matrix optical switch was designed and fabricated according to the calculated results. The silica waveguide propagation loss of 0.1dB/cm and waveguide-fiber coupling loss of 0.5dB/point were measured. With the fabricated 8×8 matrix optical switch, optical insertion loss of 4.6 dB, cross-talk of -38 dB, polarization dependent loss of 0.4 dB, averaged switching power of 1.6 W, and switching time of 1 ms were achieved. A basic agreement between experimental results and theoretical calculated values was achieved.
The Process of Interior Progressive Addition Lens
Authors: Qin Lin Ling , Yu Jing Chi , Chen Hao
Published: March 2009

The characteristics of Progressive addition lens (PAL) are described in this paper.
Theoretical analysis of advantages of Interior PAL is put forward, and the measurement results of
Interior PAL are given. Theoretical and measurement results are consistent by comparing Interior
PAL and Exterior PAL. Then the working procedures of freeform CNC machine of making Interior
PAL are introduced concisely. Also, the experiments were carried out to analyzing the processing
results in turning and polishing. From the results, it is explicit that the lens’ form accuracy is
controlled in turning and lens’ better surface finish can be obtained in polishing. The factors
affecting surface roughness are discussed explicitely based on experiment. The effects of lens
material and cutting speed on surface roughness in turning were investigated. The experimental data
show that better surface finish can be obtained by using lens material with higher rigidity and using
higher cutting speed. Polishing time and pressure influence surface roughness signally in polishing.
The reasonable ranges of polishing parameters which could bring about better surface finish are
obtained in the experiment. The ranges of polishing time and polishing pressure are 50s—100s and
0.3bar—0.6bar (1bar=0.1MPa) respectively.
Novel Design of Confocal Fluorescence Detecting System for Capillary Array and Microchip DNA Fragment Analysis
Authors: Zheng Hua , Wang Li Qiang , Shi Yan , Wang Jie , Lu Zu Kang
Published: March 2009

A novel multi-channel DNA fragment analysis system is presented，which is based on
single PMT confocal fluorescence detection and optical scanning adopting an f-theta lens. Capillary
electrophoresis experiments were executed in the system for DNA marker pBR322/Hae III. Signal
was processed with wavelet denoising. The system’s limit of detection (dsDNA with the probe of
Thiazole Orange, TO) was evaluated to be 1.1841×10-11mol/L. Its working noise is much lower
compared with that based on mechanical scanning one, and the stability and detecting sensitivity is
high. The system was expected to be applied to both capillary array and microchip electrophoresis
detection based on laser-induced fluorescence.
The Roughness Measurement and Assessment of the Super-Smooth Surface of Hard Disks
Authors: Yang Shu Ming , Jiang Xiang Qian
Published: March 2009

The rate of increasing storage capacity is being slowed by the inability to produce ever
closer flying heights between the sliders and disks. In order to allow the sliders to ‘fly’ faster and
more closely to the disk surfaces, it is important to control the surface of substrates of hard disks to
a super-smooth level. However, there are no sophisticated instruments and assessment standards
for super-smooth surfaces. In this research, the authors attempt to build a measurement and
assessment protocol for the evaluation of super-smooth surfaces using a white-light optical
instrument CCI (Coherence Correlation Interferometer). The key advantage of this instrument is its
exceptionally high vertical resolution which is an order of magnitude better than comparable
systems. This paper focuses on discussing the factors influencing the experimental results; they
include sampling intervals, the number of measurements, scan size, filter cut-off wavelength etc.
Based on the experimental results, an optimum protocol for measurement and assessment are
recommended, and then the authors measure and compare the surface roughness of six hard disks
derived from differing chemical mechanical polishing (CMP) ‘abrasives’. It has been found that:
(1) the roughness values of the six hard disks surfaces have all reached a sub-nanometre level; (2)
CMP regimes have little influence on the topography of the hard disk surfaces.
Investigation on the Modeling and Ageing Characteristics of the HID Car Headlight Automotive System
Authors: Dong Ping , Cheng Ka Wai Eric , Wang Dao Hong , Divakar Bangalore Prabhakar
Published: March 2009

In this study, ageing effect for xenon through experiment has been studied. The study
focuses on the modeling, ageing characteristics of xenon car headlight. The modeling of the lamp is
based on spline interpolation algorithms. In this model, the voltage drop at the electrodes is
considered as the aging factor. Ageing characteristics under the flicker condition for 4 types of
xenon car headlight lamps have been measured. The flicker time is 4 seconds turn on and 2 seconds
turn off, and the total testing time is 48 hours. The luminous, voltage and current of the lamp are
measured. It is found that even a short period of flicker significantly affects the life time of the
lamp.
Grain Size Effect in Sheet Metal Microforming Simulation Adopting Strain Gradient Concept
Authors: Lee Wing Bun , Chen Yi Ping , To Suet
Published: March 2009

A strain gradient dependent crystal plasticity approach is adopted to model the size effect
in the microforming process of sheet metal. To take into account the grain size effect in the
simulation, the total slip resistance in each active system was assumed to be due to a mixed
population of forest obstacles arising from both statistically stored and geometrically necessary
dislocations. The non-local crystal plasticity has been established by directly incorporating the
above slip resistance into the conventional rate-dependent crystal plasticity and implemented into
the Abaqus/Standard FE platform by developing the user subroutine UMAT. The formulation has
been recapitulated and followed by presentation of the numerical examples employing both the
local and non-local formulation. The comparison of the counterpart simulation results reveals the
grain size effect in the microforming process and demonstrates the availability of the code
developed.
A Review on Machining of Micro-Structured Optical Molds
Authors: Riemer Otmann
Published: March 2009

The manufacturing of optics is an important field of technology and will serve keymarkets
today and in the future. Nevertheless, the application of complex optical elements is much
restricted today despite of their outstanding functional advantages. Furthermore, the replication of
structured optical components requires high precision molds. Diamond machining processes like
diamond milling and cutting as well as abrasive polishing are appropriate micro-structuring
techniques for optical molds. The combination of these key machining technologies with replication
techniques within closed process chains will open the possibility to produce high precision complex
optical elements as mass-product articles for many optical applications. Important machining
techniques for optical mold manufacture are presented and discussed.
Study on Flow Imbalance during Filling a Multi-Cavity Mold Using a H-type Runners
Authors: Yang Sen Yeu , Huang Tzu Chien , Huang Po Hsun , Ko Tai Yu
Published: March 2009

This study reports the experimental investigation on the flow imbalance phenomena
during filling symmetrical multi-cavity in injection molding of optic elements. There are two
aspects in this study: First, the flow imbalance in the eight-cavity mold with normal H-type
symmetric runners were observed and measured with aid of short-shot experiments. Second, the
effects of three processing conditions including injection speed, melt temperature and mold
temperature on flow imbalance were investigated. Flow imbalances are consistently observed and
quantitatively measured. The results have shown that proper injection speed, high melt and high
mold temperature can reduce the flow imbalance.
Kinematics Calibration of Parallel Kinematic Machine Using a Developed Double-Ball Bar Gauge
Authors: Yang Xiao Jun , Li Bing , Zhang Dong Lai
Published: March 2009

In this paper a novel constraint calibration technique for Stewart platform based Parallel
Kinematics Machine(PKM) is presented. A commercial trigger probe and a developed double-ball
bar gauge are employed to aid the calibration. In the measuring process the characterized errors can
be obtained by comparing the nominal characterized size calculated by the function using the
measuring data with the real size of the double-ball gauge. An optimization approach is used to
calculate the PKM structural errors, and these errors can be finally compensated into the control
model. The error transferring matrix with regard to the structural error of PKM can be formulated.
The calibration efficiency can be improved by the automatic calibration operation with the doubleball
bar gauge. The developed calibration system has been applied in the industry where the PKM is
used for machining the turbine vane, and the machining quality can meet the requirements of the
specifications. The presented calibration scheme is generic to be applied for the wide range of
PKMs.
Research on Mathematical Models of New Diamond Turning for Non-Axisymmetric Aspheric Mirrors
Authors: Han Cheng Shun , Zhang Long Jiang , Dong Shen
Published: March 2009

In this paper, a new generation method for diamond turning non-axisymmetry aspheric
mirrors is introduced. A rotary arm that carried a diamond tool combined with fast tool servo was
used to replace the straight guides employed by most diamond turning machines. The micro linear
feed of the fast tool servo was real-time calculated with the use of high resolution angular feedback
on the work spindle and the swing tool. Synchronized motion of the fast tool servo according to
rotating angles of the workpiece and the diamond tool produced ultra-precision non-axisymmetry
aspheric surfaces. The corresponding mathematical models of NC program are presented.
Design of the Servo System for the Micro Milling Machine
Authors: Wang Bo , Wang Ju Xiang , Liang Ying Chun
Published: March 2009

To manufacture the micro parts or micro structures effectively and precisely, a high
precision 3-axis micro milling machine is built. All the three axis are driven by linear piezoelectric
ultrasonic motors and the slides are supported by cross-roller guide. Investigations are firstly made
to analyze the impact of the non-linear characteristics in the servo mechanism on the performance
of the servo system. To achieve the positioning and tracking accuracy at sub-micrometer and
micrometer level respectively, on one hand, a optical linear encoder with the resolution of 50nm is
applied to close the control loop and a high performance DSP based motion control card is used to
carried out the reference command. On the other hand, sophisticated control and compensation
strategies are also implemented to overcome the non-linear characteristics in the servo system.
Positioning and tracking experiments show that, with this well-tuned control system, the positioning
and tracking accuracy are ±0.5μm and ±2.4μm respectively. Using this machine, a micro part with
5μm thin-walled structure is machined successfully.
Study on Manufacturing Process Optimizing of Lightguiding Plate for Soft Computing
Authors: Lin Yi
Published: March 2009

This paper discusses the research of optimal process for lightguiding plate of backlight
module of liquid crystal display. The PMMA material was used on lightguiding plate. This paper
indicates that the different processing parameters (mold temperature, injection temperature, first
period injection speed, second period injection speed, third period injection speed, packing pressure
and packing time) are important for optimal research for lightguiding plate of backlight module.
This paper introduces the extension engineering, simulated annealing and genetic algorithm on soft
computing for optimal process and compares the results with experiment. The results show that the
optimal process group is A1 B1C2 D3 E2 F2 G3 for extension engineering, simulated annealing,
genetic algorithm or experiment. The mold temperature is the most important processing parameter
of the flatness of lightguiding plate for soft computing and experiment. The calculation times for
extension engineering, simulated annealing and genetic algorithm are less than experiment’s time.
Study on Micro Fabrication of Mold Insert for Microlens Arrays by Micro Dispensing
Authors: Shen Yung Kang , Lin Yi , Sheu Dong Yea , Ger Ming Der , Hu Yi Han , Hong Rong Hong , Wang Shung Mang
Published: March 2009

This work used micro dispensing technology to fabricate the master of microlens array,
then uses electroforming technology to replication the Ni mold insert of microlens array and finally
used micro hot embossing to replicate the plastic microlens array. This work used the Si10 resin by
AutoStrade Company for dispensing material. The resin material was exposed to 80W halogen
light. The resin will be hardened and become convex by surface tension effect on exposition. It can
be used as the master of microlens array. This work sputtered a silver layer of 150 nm thick on the
master for conducting electricity layer. The electroforming technology replicateed on the Ni mold
insert from the master of microlens array. Finally, the micro hot embossing technology was used to
replicate the molded microlens array. The molding experiment used PMMA and PC optical film.
The experiment studied the influence of processing parameters of hot embossing by processing
temperature, embossing pressure, embossing time and de-molding temperature. This work used the
Taguchi’s Method to search the best processing parameter for molded microlens array. This work
used the microscope, surface profiler and SEM to measure the surface profile of master, mold insert
and molded microlens array. This work also used AFM to measure the surface roughness of master,
mold insert and molded microlens array. In addition, this work measured the optical strength and
the focal length to discuss optical characteristics of molded microlens array.
Determining the Thickness and Refractive Index of a Birefringence by Using an Improved Accurate Measurement System
Authors: Yeh Yen Liang , Wang Cheng Chi , Jang Ming Jyi , Lin Yen Pin , Chen Kuang Sheng
Published: March 2009

This paper presents a high-precision, non-destructive measurement system for
determining the thickness and refractive indices of birefringent optical wave plates. Significantly,
the proposed method enables the two refractive indices of the optical sample to be measured
simultaneously. The performance of the proposed system is verified using a commercial quartz
optical wave plate with known refractive indices of 1.5518 e n = and 1.5427 o n = , respectively, and
a thickness of 452.1428 μm. The experimentally determined values of the refractive indices are
found to be 1.55190 e n = and 1.54281 o n = , respectively, while the thickness is found to be 452.189
μm, corresponding to an experimental error of approximately 0.046 μm. The measurement
resolution of the proposed system exceeds that of the interferometer hardware itself and provides a
simple yet highly accurate means of measuring the principal optical parameters of birefringent glass
wave plates.
Method of Analyzing the Singlet F-Theta Scan Lens for Laser Drilling System
Authors: Chen Ming Fei , Chen Yu Pin , Hu Chun Wei , Chen Chien Chuan
Published: March 2009

The scanning system which uses the non-linear focusing lens is usually accompanied by a major problem that is a non-constant scanning velocity of the spots in the projection plane. Moreover, the energy of the spots and the shape of the drilling holes would be affected. Hence, the focal lens of the scanning system usually uses the f-theta lens to solve this problem. This paper proposes a method utilizing the ZEMAX to analyze the commercial F-theta lens. The results indicate the F-theta lens can increase the quality of the drilling holes and amend the projection plane. In order to verify the analysis results, each diameter of an array holes drilled by the CO2 laser drilling machine would be measured. The experimental results can demonstrate that the percentage of the variation in the diameter of holes is close to the simulation results. Therefore, the method can effectively analyze the F-theta lens of the scanning systems.
Advanced Smart High Ratio Zoom System with Global Optimization
Authors: Ding Quan Xin , Liu Hua
Published: March 2009

With an aim to achieve a breakthrough the choke point in research on system design, to
achieve the transforming in multiple fields of view, the approaching to system efficacy limit in
theory and improving smartness, pure diffractive optical system is chosen. The top idea and main
strategy is developed. Some correlative model is established. In optimized design, global
optimization algorithm is used to achieve wider spectrum range, multi field view, lower distortion
and appropriate MTF. A kind of result works mainly in 3~5%m and 8~12%m with high ratio of more
than 20:1 is evaluated. And this integrated multi-sensor electro-optical system satisfies the applied
requirements o some criteria, such as Modulation Transfer Function (MTF), Spot Diagram (RMS)
and Point Spread Function (PSF) etc., and achieves remarkable advantages in volume, weight,
system efficiency and so on.