bluuebunny/crossref_metadata_2025 huggingface dataset:
Resistance Heating Characteristics of High-Strength Steel Sheet Blank for Hot Press Forming
Authors: Maki Seijiro , Tanaka Yuuki , Mori Kenichiro
Published: March 2009

Resistance heating performance in some shaped blanks of high-strength steel sheet is
examined by experiment and FE simulation, and the feasibility and effectiveness of the application of
resistance heating to the hot press forming of high-strength steel sheet are discussed. The followings
are made clear through this study. (1) A uniformly distributed current density is essential to uniform
blank heating. (2) For a certain shaped blank, no matter how the electrodes are disposed, uniform
blank heating is difficult. (3) A blank shape suitable for uniform heating by a single pair of parallel
electrodes is restricted to a rectangle.(4) In case a uniformly heated blank is required, two-piece
simultaneous forming with point-symmetric die layout is recommended from the viewpoint of
material utilization.
Increase of Wall Thickness around Corner of Multi-Stage Drawn Cup with Flange Using Conical Punches
Authors: Tan C.J. , Abe Y. , Mori Kenichiro , Ebihara O. , Nonaka T.
Published: March 2009

The wall thickness around an inner corner in 3-stages formed cups with a flange was
increased by means of conical punches in the 1st and 2nd stages. Since the strength of the formed
cups is greatly improved by the increase in wall thickness, the weight of the formed products is
reduced by an optimum distribution obtained from the increase in wall thickness. The increase in
thickness around the inner corner is obtained by compressing the side wall and conical bottom of
the cup in the 3rd stage. As the punch angle increases, the increase in thickness at the inner corner
becomes large. The amount of compression is expressed by a drawn volume after the 2nd stage. A
maximum 9% increase in wall thickness around the inner corner was successfully obtained for the
punch angle of 25º.
Effect of Texture on High Temperature Deformation Behaviors of Ti-6Al-4V Alloy
Authors: Park J.E. , Jeon J.B. , Semiatin S. Lee , Lee Chong Soo , Chang Young Won
Published: March 2009

Textures developed during hot rolling process may affect the high temperature deformation
behaviors of Ti alloys, but their relation has not been well understood or quantitatively analyzed yet.
A series of load relaxation and creep tests for hot rolled Ti-6Al-4V alloy has been conducted in this
work to clarify the effect of textures on the deformation behaviors of the alloy under 700 °C and the
result was analyzed by using an internal variables approach. The internal strength σ* was found to
vary significantly by the textures, but not by the temperature change, while the texture effect was found
to decrease at higher temperatures.
Processing Conditions and Mechanical Properties of Fine Grained Mg by Equal Channel Angular Pressing
Authors: Yoon Seung Chae , Jeong Young Gi , Hong Sun Ig , Chun Byong Sun , Lee Hong Rho , Baik Kyeong Ho , Kim Hyoung Seop
Published: March 2009

Mg and Mg alloys are promising materials for light weight high strength applications. In
this paper, grain refinement of pure Mg using severe plastic deformation was tried to enhance
mechanical properties of the hard-to-deform metallic material. The microstructure and the
mechanical properties of Mg processed by equal channel angular pressing (ECAP) at various
processing temperatures were investigated experimentally. ECAP of channel angle of 90o and
corner angle of 0o was successful without fracture of the samples at 300 oC. The hardness of the
ECAP processed Mg decreased with increasing ECAP processing temperature. The effect of
temperature on the hardness and microstructure of the ECAP processed Mg were explained by the
dislocation glide in the basal plane and non-basal slip systems and the dynamic recrystallization and
recovery.
Experimental Study on Mechanical Energy Hysteresis in Nano Colloidal Damper Using Porous Silica Particle
Authors: Jeon Sang Bae , Ku Tae Wan , Kim Jeong , Kang Beom Soo
Published: March 2009

Mechanical damping systems have been widely used to various industrial structures and are
mainly hydraulic and pneumatic devices nowadays. This article presents an experimental
investigation of a nano colloidal damper. Particularly for colloidal damper, the hydraulic oil is
replaced by a colloidal suspension, which is consisted from a nano-porous matrix with controlled
architecture and a lyophobic fluid. Nano colloidal damper test rig and the measuring technique of the
hysteresis were described in this study. Influence of the water volume and particle diameters upon the
nano colloidal damper hysteresis was investigated. As a result, the proposed nano colloidal damper
(NCD) is proved as an effective one, which can be replaced for the conventional hydraulic damper.
Molecular Dynamics Analysis on Crack Growth Behavior in Single and Nano-Crystalline Fe by the Use of FS-2NNMEAM Hybrid Potential
Authors: Kubota Yoshihiro , Matsumoto Ryosuke , Nakagaki Michihiko
Published: March 2009

In recent years, nano-crystalline materials have attracted many researchers’ attention, but
the fracture mechanism has not been fully clarified. In a molecular dynamics (MD) simulation, grain
size and crystal orientation can be chosen, and their effects on the mechanical properties of
nano-crystalline materials can be evaluated clearly. This research first compares the results of crack
growth behavior in single crystalline Fe for three typical interatomic potentials (Embedded Atom
Method (EAM), Finnis Sinclair (FS), and Second Nearest Neighbor Modified EAM (2NNMEAM)
potentials) and a Hybrid potential method, which uses FS potential for bcc structure atoms and
2NNMEAM potential for non-bcc structure atoms. The 2NNMEAM potential is accurate, but the
computation time is dozens of times that of FS potential, which is the simplest of the three interatomic
potentials. Therefore, the 2NNMEAM potential requires too much calculation for the purpose of this
research that analyzes the crack growth behavior in nano-crystalline metals. However, Hybrid
potential is able to give results similar to those of the 2NNMEAM potential, and the calculation time
is close to that of the FS potential. From these results, the crack extension behavior in relatively large
nano-crystalline models is analyzed using the Hybrid potential, and we demonstrate the grain-size
dependency of the fracture behavior.
Manipulation of Intrinsic Localized Modes by Elastic Waves in One Dimensional Anharmonic Lattice Systems
Authors: Doi Y. , Nakatani Akihiro
Published: March 2009

Manipulation of the intrinsic localized modes (ILMs) or discrete breathers (DBs) in the one
dimensional anharmonic lattice systems is investigated. We can make a static ILM into a moving one
without any collapses of localized structure by introducing the suitable linear plane into the system.
Also we can make a moving ILM into a static one by the same way. Using these procedures, ILM’s
position in the system can be controllable. This result indicates the possibilities of applications of
ILMs in practical discrete systems in the future.
A Developmental Study of Artificial Skin Using the Alginate Dermal Substrate
Authors: Park Dae Hwan , Choi Won Seok , Yoon Sean Hyuck , Shim Jung Soo , Song Chul Hong
Published: March 2009

Alginate, which is isolate from brown seaweed, a bioabsorbable long chain
polysaccharides of guluronic acid and mannuronic acid. The authors produced alginate, fibroblastgrowth-
factor mixed alginate and alginate-collagen complex as a disc form. For study of wound
healing, full thickness skin defects were made on the dorsal area of the animal model. And then
alginate, fibroblast-growth-factor mixed alginate, alginate-collagen complex, vaseline gauze as
control were applied on the wound and evaluated grossly and histopathologically. For
biocompatibility test, alginate and alginate-collagen complex discs were implanted on back of New
Zealand white rabbits. And we measured size of wound healing, size of wound epithelization, size
of wound contracture at 5, 10, 15, 20, and 25 days. Four weeks after implantation, implanted
animals were examined immunologically against alginate and collagen. Alginate and FGF-mixed
alginate, alginate-collagen complex group showed statistically higher percentage of wound
contraction and wound healed than control group(p<0.05) Alginate-collagen complex group and
FGF-mixed alginate group showed statistically higher percentage of wound healed than alginate
group. In conclusion, high-purified alginate from seaweeds by our purification method, has the
ability of wound healing and addition of FGF or collagen increase the ability of alginate, it shows
the possibility of alginate as dermal substrate.
A Mineralization Study of Various Human Dental Stem Cells
Authors: Lee Hee Jung , Jo You Young , Kook Sun Young , Seo Byoung Moo , Choung Pill Hoon
Published: March 2009

In this study, various dental stem cells were isolated and their mineralization ability was
evaluated. First, we isolated postnatal stem cells from human dental tissues such as dental pulp
(DPSCs), periodontal ligament (PDLSCs), periapical follicle (PAFSCs) and mandibular bone
marrow (MBMSCs). Then, we cultured these dental stem cells in the mineralization condition for
21 days. Ability of these stem cells to mineralize was evaluated by Alizarin Red staining,
quantitative analysis of Alizarin Red, alkaline phosphatase (ALP) activity, and RT-PCR. The
calcium deposits of PAFSCs were sparsely scattered throughout the adherent layer, whereas
MBMSCs and PDLSCs cultures produced extensive sheets of calcified deposits over the entire
adherent layer. Quantitative Alizarin Red staining and the ALP activity also were high in MBMSCs
and PDLSCs. In the osteogenic differentiation condition, all of dental stem cells showed
upregulated expression of the mineralization-related gene. Our findings suggest that isolated DPSCs,
PDLSCs, PAFSCs and MBMSCs have the different mineralization abilities.
Scaffold Fabrication with Biodegradable Poly(propylene fumarate) Using Microstereolithography
Authors: Lee Jin Woo , Kim Byung , Lim Geun Bae , Cho Dong Woo
Published: March 2009

Although tissue engineering is an area with great potential, it still has few applications
due to the lack of biocompatible, biodegradable materials with suitable mechanical properties.
Recently, several biodegradable materials were developed, of which poly(propylene fumarate (PPF)
is one of the most notable. It degrades into fumaric acid and propylene glycol, which are both
biocompatible products. Microstereolithography is a new technology that can be used to fabricate
free-form 3-D microstructures by dividing a desired shape into many slices of a given horizontal
thickness. This technology requires a low-viscosity resin to fabricate fine structures. However, the
viscosity of PPF is too high to fabricate 3D structures using microstereolithography. Therefore, we
reduced the viscosity of the resin by adding diethyl fumarate (DEF). Then, we added a
photoinitiator to photo-crosslink the DEF/PPF resin, and fabricated 2.5-D scaffolds using our
system. We confirmed that microstereolithography technology is effective in scaffold fabrication.
The fabricated 2.5-D scaffolds were seeded with fibroblasts and the cells attached well after
seeding.
Fabrication of Scaffold-Free Engineered Cartilage Using Passaged Chondrocytes in the Presence of Insuline Like Growth Factor 1 (IGF-1)
Authors: Jin Ri Long , Park So Ra , Son Jeong Hwa , Min Byoung Hyun
Published: March 2009

Two passaged (P2) immature porcine articular chondrocytes were used to fabricate an
engineered cartilage tissue in an in vitro scaffold-free system with or without insulin like growth
factor 1 (IGF-1). This study shows the possibility of the fabrication of structurally regular neocartilage
tissue using passaged chondrocytes in the scaffold-free system with insulin like growth
factor-1(IGF-1).
Fibrinogen Concentration Influence on VEGF-Induced Differentiation of Adipose Tissue-Derived Stem Cells into Endothelial Cells
Authors: Kim Hyeong In , Seo Ji Yeon , Jeung Seung Jo , Park Sae Gwang , Yang Young Il
Published: March 2009

Fibrin is a natural substrate for growth, adhesion, and migration of mature endothelial
cells (ECs) and a candidate coating material in approaches to graft endothelialization. Adipose
tissue represents an abundant, practical source of donor tissue for stem cells which may be a useful
source for engineering of vascular grafts. However, the optimal substrates that promote
differentiation of adipose tissue-derived stem cells (ASCs) into ECs remain to be elucidated. In the
present study, we investigated whether fibrin can be used as a substratum to support in vitro ECs
differentiation of ASCs and whether fibrinogen concentration can be affect on ECs differentiation of
ASCs. For determination of phenotypic characteristics of ASCs used in this experiment, we
performed flow cytometry analysis. ASCs were plated on fibrin composed of varying
concentrations of fibrinogen and induced into ECs differentiation in presence of VEGF. Before
inducing into ECs, ASCs did not express any markers of hematopoietic cells (CD34, CD45), ECs
(CD31, CD34), and endothelial progenitor cells (CD34, CD133, Flk-1). The degree of ECs
differentiation was determined by capillary network formation, ECs-specific gene expression, and
F-actin assembly. During the first 12 h after seeding, cells spread randomly, moved and formed
small interconnected clusters. These clusters decreased in size and formed a capillary tube at 48 h.
During the further incubation in presence of VEGF for 7 days, ASCs expressed mRNA and protein
of von Willebrand factor (vWF). The degree of ECs differentiation of ASCs was consistently
decreased as fibrinogen concentration increase. Fibrin may be used as biomatrix to promote
differentiation of ASCs into ECs for tissue engineering.
Injectable Chitosan Carrier for Demineralized Bone Matrix
Authors: Kim Yu Han , Cho Mi Hee , Song In Bum , Hyun Hoon , Lee Jung Won , Kim Moon Suk , Seo Seog Jin , Kang Ke Won , Khang Gil Son , Yang Sung Yun , Lee Hai Bang
Published: March 2009

In this study, we developed an injectable carrier for demineralized bone matrix (DBM)
which consists of chitosan and glycerol phosphate (GP). The phase transition behaviors of chitosan
and GP solution characterized as a function of temperature. The chitosan and GP solutions were
shown to form a sol at room temperature, and the chitosan solution with 10-20 wt% concentrations
were found to undergo sol-to-gel phase transitions as the temperature was increased. In situ gel
forming implant in vivo was successfully fabricated by simple subcutaneous injection of chitosan
and GP solutions with demineralized bone matrix (DBM). von Kossa images of the gel implant
formed from solution with DBM revealed the presence of mineral deposits.
Co-Electrospinning of Microbial Polyester/Gelatin and their Interaction with Fibroblasts
Authors: Yun So Hee , Jun Ga Young , Yoon Kwan Han , Park Yong Soon , Kim Young Jin , Kang Inn Kyu , Kwon Oh Hyeong
Published: March 2009

Biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofibrous
matrix containing gelatin was fabricated by electrospinning method. The average diameter of
electrospun PHBV/Gelatin (1:1) nanofibers was 600 nm determined by FE-SEM. ATR-FTIR and
ESCA measurements were used to confirm the presence of gelatin in PHBV/Gelatin nanofibers.
Human fibroblasts' behavior on PHBV/Gelatin nanofibrous matrix has been investigated.
Fibroblasts were well attached on the surface of control PHBV and PHBV/Gelatin nanofibers.
Initial cell attachment on PHBV/Gelatin nanofibers was higher than that of control PHBV
nanofibers. Gelatin has many RGD moiety that mediate cell attachment. From this reason, initial
cell attachment increased on the surface of PHBV/Gelatin nanofibers. From the results, coelectrospinning
of PHBV and gelatin is a promising method for tissue engineering scaffold.
A Novel Cell Co-Culture Method Utilizing Thermo-Responsive Surface
Authors: Bae Jin Suk , Jun Ga Young , Kikuchi Akihiko , Okano Teruo , Ahn Chang Hyun , Kim Young Jin , Kang Inn Kyu , Kwon Oh Hyeong
Published: March 2009

In this work, we developed a novel patterned co-culture method with thermo-responsive
poly(N-isopropylacrylamide) (PIPAAm) and poly(N-ρ-vinylbenzyl-Ο-β-D-galactopyranosyl-(1→
4)-D-gluconamide) (PVLA) inducing active hepatocyte attachment. Patterned graft of PIPAAm
onto PS dishes was carried out by electron beam irradiation using cover-glass as a photomask.
PVLA was only coated onto PIPAAm-ungrafted domain because of hydrated hydrophilic property
of PIPAAm at below the LCST. Analysis by attenuated total reflection-Fourier transform infrared
and electron spectroscopy for chemical analysis revealed that PIPAAm and PVLA were
successfully grafted and coated on surfaces of PS dishes. PIPAAm-grafted surface exhibited
decreasing contact angle by changing temperature from 37 to 20°C, while PVLA-coated PS and
non-treated PS had negligible contact angle changes with temperature alternation. Atomic force
microscopy (AFM) results showed that PIPAAm-grafted and PVLA-coated PS had smoother
surfaces than that of ungrafted PS dishes. After culture for 12 hours, hepatocytes were well attached
on PVLA-coated domain. Hepatocytes adherent on PIPAAm-grafted domain were detached by
decreasing temperature. And then, fibroblasts were seeded onto PIPAAm pattern-grafted domain.
Fibroblasts were only attached and spread onto PIPAAm-grafted domain. Co-cultured hepatocytes
showed better differentiated function of albumin expression compared to homotypic hepatocyte
culture
Research on the Growth Density of the Capillaries and the Configuration of the Porous Silk Fibroin Film
Authors: Bai Lun , Xu Jian Mei , Sun Qi Long , Di Chuan Xia , Wu Zheng Yu
Published: March 2009

In order to obtain porous silk fibroin films that suit all kinds of different tissue and organs,
to design the configuration of the porous silk fibroin films more rationally, this paper made a
modeling of the oxygen diffusing system of the capillary, and also solved the model. Moreover the
paper gave a method to estimate the density of the capillaries in the tissue; and hereby brought
forward the basic requirements in designing the configuration of the porous silk fibroin film.
Genotoxic Potential of Regenerated Silk Fibroin Films by Different Cross-Linking Mode
Authors: Miao Jing Cheng , Sheng Wei Hua , Li Ming Zhong , Xie Yu Feng , Gong Ai Hua , Yang Ji Cheng
Published: March 2009

Emerging studies have showed that silk fibroin might be as a naturally occurring
degradable biomaterial for tissue engineering with unique mechanical properties, biocompatib
ility and processability. To optimize the formation of the regenerated silk fibroin film, in thi
s study, we examined the genotoxic potential of the regenerated silk fibroin films by differe
nt cross-linking mode with micronucleus and the single cell gel electrophoresis (comet) assa
y. The data showed that MNF in group PC and group SD showed significantly no differenc
e with blank group (P>0.05), and no evident comet tails were observed. However, the resul
t of EC group was significantly different from the control group(P<0.01). Taken together, R
SFFs in group PC and group SD have no evident genotoxicity, which is better than group
EC.
Effects of Mechanical Stress on the In Vitro Degradation of Porous Composite Scaffold for Bone Tissue Engineering
Authors: Kang Yun Qing , Yin Guang Fu , Luo Lin , Wang Ke Feng , Zhang Yu
Published: March 2009

In bone tissue engineering, porous scaffolds served as the temporary matrix are often
subjected to mechanical stress when implanted in the body. Based on this fact, the goal of this study
was to examine the effects of mechanical loading on the in vitro degradation characteristics and
kinetics of porous scaffolds in a custom-designed loading system. Porous Poly(L-lactic
acid)/β-Tricalcium Phosphate (PLLA/β-TCP) composite scaffolds fabricated by using solution
casting/compression molding/particulate leaching technique (SCP) were subjected to degradation in
simulated body fluid (SBF) at 37°C for up to 6 weeks under the conditions: with and without static
compressive loading, respectively. The results indicated that the increase of the porosity and
decrease of the compressive strength under static compressive loading were slower than that of
non-loading case, and so did the mass loss rate. It might be due to that the loading retarded the
penetration, absorption and transfer of simulated body fluid. These data provide an important step
towards understanding mechanical loading factors contributing to degradation.
Fabrication and Characterization of Hydrophilized Polydioxanone Scaffolds for Tissue Engineering Applications
Authors: Cho Kwang Joon , Song Dae Keun , Oh Se Heang , Koh Young Joo , Lee Sahng Hoon , Lee Myung Chul , Lee Jin Ho
Published: March 2009

Porous polydioxanone (PDO)/polyvinyl alcohol (PVA) scaffolds were fabricated by
blending PDO with a small amount of PVA to improve the hydrophilicity and cell/tissue
compatibility of the scaffolds for tissue engineering applications. PDO/PVA scaffolds with different
PVA compositions up to 10 wt% were fabricated by a melt-molding particulate-leaching method
(non-solvent method). The prepared scaffolds exhibited highly porous, uniform open-cellular pore
structures. The PDO/PVA scaffolds with PVA compositions more than 5 % were easily wetted in
cell culture medium. The hydrophilized PDO/PVA (5 wt%) scaffold showed better cell adhesion
and growth than the control hydrophobic PDO scaffold. The PDO/PVA (5 wt%) scaffold also
showed faster tissue infiltration into the scaffold than the PDO scaffold. It seems that 5 wt%
addition of PVA to PDO to fabricate PDO/PVA scaffolds is enough for improving the
hydrophilicity and cell/tissue compatibility of the scaffolds.
Bone Grafting Using Particulate Dentin
Authors: Kim S.G.
Published: March 2009

I tested the effectiveness of a particulate dentin and plaster of Paris mixture as a bone
substitute. Histologic analysis indicated that all of the bone defects surrounding the implants treated
with particulate dentin/plaster of Paris were filled with new bone 6 and 12 weeks after surgery. No
significant differences were observed in the new bone forming activity in any species (human,
bovine, pig, rabbit, and dog). No cytotoxicity was detected in cell cultures with added particulate
dentin extract and no specific allergic reactions were seen in the hypersensitivity test. These results
suggested that the combination of particulate dentin and plaster is suitable as an alternative bone
substitute.
Evaluation of RGD-Grafted Porous PLLA Scaffold for Chondrogenic Differentiation of Stem Cells
Authors: Jung Hyun Jung , Park Kwi Deok , Cho Kyoung Jin , Ahn Kwang Duk , Ahn Dong June , Han Dong Keun
Published: March 2009

Biodegradable porous poly(L-lactic acid) (PLLA) scaffolds were prepared using gas
foaming method. The PLLA scaffolds with a hydrophobic surface were subjected to Ar plasma
treatment and in situ acrylic acid (AA) grafting to obtain hydrophilic PLLA scaffold (PLLA-PAA).
Cell-adhesive RGD peptide was then immobilized onto the AA-grafted PLLA (PLLA-PAA-RGD).
Once rabbit bone marrow-derived mesenchymal stem cells (BM-MSC) were isolated, MSCs were
seeded into PLLA control, PLLA-PAA, and PLLA-PAA-RGD scaffold and cultured for up to 4
weeks in chondrogenic medium with the addition of 10 ng/ml transforming growth factor (TGF)-β1.
Surface analysis of AA-grafted PLLA identified significant alterations of surface characteristics,
including reduced contact angle and different atomic compositions. From WST-1 assay at 4 weeks,
cells were found more proliferative in PLLA-PAA than the others. Upon the histological analysis of
Safranin O staining, chondrogenic differentiation of MSCs appeared to be progressed more actively
in PLLA-PAA. The effect of RGD immobilization on MSC differentiation was barely notable.
Laminin Immobilized on Titanium Oxide Films for Enhanced Human Umbilical Vein Endothelial Cell Adhesion and Growth
Authors: Ge Sh.N. , Chen Jun Ying , Leng Yong Xiang , Huang Nan
Published: March 2009

In prior work we have shown that titanium oxide (Ti-O) thin films have good blood
compatibility. However, as well as being hemocompatible, biomaterials used in contact with blood
should be cell compatible also. In the work described here, Ti-O films were synthesized using
unbalanced magnetron sputtering (UBMS) and were modified by immobilizing laminin on the film
surface for improving human umbilical vein endothelial cell (HUVEC) adhesion and growth.
Scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR) and
contact-angle measurements were used to investigate the surface characteristics of the Ti-O films
and the modified Ti-O films. The results suggest that Laminin can be biochemically immobilized on
the Ti-O film surface. The modified layer of Laminin can improve the hydrophilicity and wettability
of Ti-O films. In vitro HUVEC investigations reveal that Laminin immobilized on the film surface
greatly enhances cell adhesion and growth on Ti-O films.
Effect of Rapamycin/Curcumin Co-Loaded Poly(Lactide-Co-Glycolide) Films on Blood Compatibility and Vascular Smooth Muscle Cell Proliferation
Authors: Wang Jin , Tang Jia Ju , Ren Ling , Pan Chang Jiang , Huang Nan
Published: March 2009

Rapamycin/curcumin co-loaded and rapamycin-loaded poly(lactide-co-glycolide)(PLGA)
films were prepared by a casting method. The components of different drug-loaded films were
analyzed by Fourier transform infrared spectroscopy (FTIR), and the major peaks of rapacymin and
curcumin were both observed in these films. Compared to the rapamycin-loaded film, the results of
in vitro platelet adhesion tests show that the number of adhered platelets reduce, and few aggregated
and activated platelets are observed. The APTTs (activated partial thromboplastin time) of
rapamycin/curcumin co-loaded films is nearly 6 seconds longer than for the rapamycin-loaded
PLGA films. All results indicate that curcumin may suppress thrombosis activated by rapamycinloaded
film, and improve the anticoagulative property. The results of alamar blue indicate that the
rapamycin/curcumin co-loaded film has better antiproliferation effect than 316 stainless steel (SS).
Effects of Hormone Treatment on the Mechanical Characteristics of Osteoporotic Vertebral Trabecular Bone Using RP and FE Models
Authors: Won Ye Yeon , Woo Dae Gon , Kim Chi Hyun , Baek Myong Hyun , Lee Tae Woo , Ko Chang Yong , Kim Han Sung
Published: March 2009

Considerable researchers analyzed the effects of hormone treatment on osteoporotic
vertebral bones. Hormone treatment of age-related osteoporotic bone has a potential to decrease an
incidence of osteoporosis. In the present paper, experimental and simulated tests for the mechanical
characteristics of osteoporotic models and their hormone-treated models were investigated. Three
dimensional (3D) geometries of the models (rapid prototyped and finite element models) were
generated from high resolution micro-computed tomography ($-CT, Skyscan 1076, Skyscan,
Belgium) scan data for the central parts of the second lumbar vertebrae. From these 3D geometries,
cubic specimens with side length 6.5mm were formed and analyzed. Rapid prototyped (RP) models,
instead of the real bone specimen, of vertebral trabecular bones were created in the fused deposition
modeling (FDM) machine. In the present study, experimental compressions test for RP models were
carried out by the INSTRON testing machine (8874 series, Instron, UK). The mechanical
characteristics of finite element (FE) models for simulated compression tests were compared with
physical predictions from RP models for experimental compression test. As a result, it is found that
the hormone therapy is likely to be less effective than reported by previous researchers. A
remarkable agreement was achieved between the results obtained from the experimental tests for
RP models and simulated tests for FE models.
Cartilaginous Tissue Formation with an Elastic PLCL Scaffold and Human Adipose Tissue-Derived Stromal Cells
Authors: Lee So Eun , Jung Young Mee , Kim Soo Hyun , Kim Sang Heon , Rhie Jong Won , Kim Young Ha , Min Byoung Goo
Published: March 2009

In cartilage tissue engineering, as a cell source, adult stem cells are very attractive for
clinical applications. Recent studies suggest that human adipose tissue-derived stromal cells (ASCs)
have multilineage potential similar to bone marrow-derived stromal cells (BMSCs). ASCs are
obtained from adipose tissue easily isolated by suction-assisted lipectomy in various body parts.
Also, as one of major factors of cartilage tissue engineering, scaffolds have an important role in
cartilage formation. Poly(L-lactide-co-ε-carprolactone) scaffolds have physiological activity,
biodegradability, high cell affinity, and mechano-activity. The object of this study is cartilaginous
tissue formation using highly elastic PLCL scaffolds and ASCs in vitro and in vivo.
Poly(L-lactide-co-ε-carprolactone) copolymers were synthesized from lactide and ε-carprolactone
in the presence of stannous octoate as catalyst. The scaffolds with 85% porosity and 300-500μm
pore size were fabricated by gel-pressing method. ASCs were seeded on scaffolds and cultured for
21days in vitro. Cell/polymer constructs were characterized by reverse transcriptase-polymerase
chain reaction for confirming differentiation to chondrocytes onto PLCL scaffolds. Also, for
examining cartilaginous tissue formation in vivo, ASCs seeded scaffolds which were induced
chondrogenesis for 2 weeks were implanted in nude mice subcutaneously for up to 8weeks.
Histological studies showed that implants partially developed cartilaginous tissue within lacunae.
And there was an accumulation of sulfated glycoaminoglycans. Immunohistochemical analysis
revealed that implants were positively stained for specific extracellular matrix. These results
indicate that ASCs and PLCL scaffols could be used to cartilage tissue engineering.
Effects Of (1→3), (1→6)-β-D-Glucan Behavior in Human Dermal Fibroblast Cells under Serum Starvation
Authors: Woo Yeon I , Son Hyun Joo , Lim Hye Ryeon , Lee Mi Hee , Baek Hyun Sook , Tsubaki Kazufumi , Park Jong Chul
Published: March 2009

Glucans have been reported to stimulate immunity and to promote wound healing. Adult
human dermal fibroblast (aHDF) cultured in serum free (serum-starvation). Proliferation of aHDF
was measured at various concentrations of β-glucan by MTT assay, and migration was observed for
36h on microscope. The result of fibroblast bioassay, β-glucan had positive influence. In this study,
the direct effects of β-glucan on proliferation and migration of human dermal fibroblasts were
examined in vitro. That means β-D-glucan has the effect to enhance proliferation and aHDF
migration speed, and has the potential as a wound healing agent.
Relationship of Morphological and Mechanical Characteristics in Vertebral Trabecular Bone
Authors: Lee Tae Woo , Ko Chang Yong , Woo Dae Gon , Kim Han Sung
Published: March 2009

Several researchers investigated the mechanical characteristics of human trabecular bone
using finite element analysis (FEA) based on micro computed tomography (μ-CT). There were few
investigations on morphological and mechanical characteristics of vertebral trabecular bones. This
study analyzed the relationship between morphological and mechanical characteristics in the
regional vertebral trabecular bones using μ-CT and μ-FEA. Two specimens were obtained from the
12th thoracic vertebral bodies of cadavers (85 years female and 48 years male). In each vertebral
body, fifteen regions were selected from two-dimensional (2D) images acquired from μ-CT. Voxelbased
three-dimensional (3D) finite element models, with 444 cubic block, were generated
from each region for simulated compression test. The relationship between morphological
characteristics, such as bone volume fraction, trabecular thickness, trabecular separation, trabecular
number and structure model index, and mechanical characteristics, such as structural modulus (E†),
was analyzed by bivariate correlation coefficient. As a result, the region of center column and
inferior layer had the highest density. However, structural moduli in center column and middle layer
were the biggest. The results indicated that there was a regional difference between morphological
and mechanical characteristics of vertebral trabecular bone. In addition, for more exact evaluation
of osteoporosis, it was recommended to analyze not only the mechanical characteristics but also the
morphology characteristics.
Permeability and Metabolism of Ba-Alginate Encapsulated Hepatocytes with Gelatin and Poly (Vinyl Alcohol)
Authors: Xing Zhi Cai , Huh Man Woo , Kang Inn Kyu
Published: March 2009

Microcapsules of alginate cross-linked with divalent cations are the most common
system for cell immobilization. In this work, the polyion complex (PIC) microcapsules were made
using sodium alginate/barium chloride as the wall materials and gelatin/poly (vinyl alcohol) (PVA)
as the extracellular matrices. The result of the permeability experiment of microcapsules using
proteins with different molecular weight showed that the capsule has a molecular weight cut-off
(MWCO) of 150 kDa. The hepatocytes encapsulated in microcapsules with gelatin and PVA in the
core rapidly aggregated as incubation time increased. The aggregated hepatocytes showed high
ammonia removal and albumin synthesis, showing a high potential for use in a bio artificial liver
system.
Alginate-Coated Thiolated Chitosan Microspheres for an Oral Drug Delivery System In Vitro
Authors: Jiang Hu Lin , Arote Rohidas B. , Quan Ji Shan , Yoo Mi Kyong , Kim You Kyoung , Kim In Yong , Hong Zhong Shan , Lee Hong Gu , Jin Xun , Choi Yun Jaie , Cho Chong Su
Published: March 2009

Thiolated polymers have been studied by many researchers because of the mucoadhesive
properties of thiol group. Alginate is a natural and biocompatible polymer that has been widely used
in drug delivery. In this study, thiolated chitosan microspheres (TCMs) were prepared by ionic
gelation process with tripolyphosphate and then, the bovine growth hormone (BGH) was loaded as
a model drug. Finally, the BGH-loaded TCMs (BTCMs) were coated with alginate to improve the
stability in gastrointestinal (GI) track. The alginate-coated BTCMs (ABTCMs) were observed as
spherical shapes. The average particle sizes of ABTCMs were 6.97±0.55 -m and the sizedistribution
was shown uniformly. Release of BGH from ABTCMs was decreased by coating with
alginate and increased rapidly with the change in medium pH from 1.2 to 7.4. Results indicate that
the ABTCMs have a potential as a drug carrier for oral drug delivery.
PEGylation of Conjugated Linoleic Acid and its Application as an Anti-Cancer Prodrug
Authors: Seo Ji Hye , Moon Hyun Seuk , Guo Ding Ding , Lee Hong Gu , Choi Yun Jaie , Cho Chong Su
Published: March 2009

The objective of this study is to investigate whether the PEGylated conjugated linoleic
acid (PCLA) as an anti-cancer prodrug can have favorable stability, biological activity, and
prevention of proliferation in MCF-7 breast cancer cells for anti-cancer when compared with
conjugated linoleic acid (CLA) itself. The CLA was simply coupled to poly(ethylene glycol) (PEG)
at melting state without solvent or catalyst through ester linkage between carboxylic group of CLA
and hydroxyl one of PEG. The results showed that the half life of PCLA was 55h in cell culture
medium at pH 7.4 and 37°C. Apoptosis of MCF-7 breast cancer cells were induced by not only
CLA- but PCLA-treatment with increasing concentrations whereas PCLA increased cell viability
when compared with CLA itself. These results indicate that the PCLA is a more stable and valuable
prodrug in that it has good stability and inhibition of cancer cell proliferation.
Optimization of Experimental Conditions for Synthesis of Nanohydroxyapatite/Collagen Composites in Situ
Authors: Lin Xiao Yan , Li Xu Dong , Zhang Xing Dong
Published: March 2009

L9 (34) orthogonal array design was employed to optimize experimental conditions for
the preparation of the composite using in situ synthesis method and to analyze the relationships
between experimental parameters and mechanical property of the composites. Bending strength of
the composite was considered as a target property of the composites. Hydroxyapatite content in the
composite, synthesis temperature and pH were chosen as main parameters. As a result of this study,
bending strength of the composite appeared in peak with the increase of the hydroxyapatite content
of the composites and synthesis pH, while with the increase of temperature, bending strength
decreased. Optimum experimental conditions for the synthesis of the composites with higher
bending strength were determined. The bending strength of the composites was 90 MPa at the
optimal synthesis conditions.
Continuous Release of Protein from Biodegradable In Situ Forming Depot
Authors: Kim Yong Hee
Published: March 2009

Biodegradable in situ forming drug delivery systems that solidify or gel in the body from
injectable fluids represent effective parenteral depot systems for controlled delivery of proteins.
Various pharmaceutical additives were tested on their effectiveness as protein release modifiers and
stabilizers. Mono-, di-, poly-saccharides, PEG2K and salting-out salts except cyclodextrins
significantly decreased Tg of thermogelling polymers and their decreasing abilities were
proportional to the polymer concentration and additive/polymer weight ratio up to solubility limits
in aqueous media. For methyl cellulose (MC) gel, sodium carbonate, a strong salting-out salt,
decreased Tg by 23 °C so that in situ gel can be formed at the body temperature. The incorporation
of additives into thermogelling polymers significantly decreased the burst and retarded release
kinetics. Although the pH inside gel gradually dropped down due to the polymer degradation,
released model protein was confirmed to retain the original conformation.
Co-Precipitation of 5-Fluorouracil and Poly(L-Lactide) Using Solution-Enhanced Dispersion by Supercritical CO2
Authors: Pu Xi Ming , Kang Yun Qing , Chen Ai Zheng , Liao Li , Yin Guang Fu
Published: March 2009

5-Fluorouracil-poly(L-lactide) (5-Fu-PLLA) microspheres have been co-precipitated in a
process namely solution-enhanced dispersion by supercritical CO2 (SEDS). First, the 5-Fu is
successfully micronized and then used to produce the 5-Fu-PLLA microspheres. The 5-Fu-PLLA
microspheres synthesized in the SEDS process exhibited a rather spherical shape, smooth surface,
and a narrow particle size distribution, where it ranged from 531 nm to 1280 nm, with a mean
particle size of 793 nm. The dichloromethane residue in the 5-Fu-PLLA microspheres is 46 ppm.
The average drug load of the 5-Fu-PLLA microspheres is 12.7%. The results of this study indicate
that the SEDS process is an effective technique to co-precipitate 5-Fu and PLLA as composite
microspheres.
Anticoagulation and Drug Release Behavior of Curcumin-Loaded PLGA Films
Authors: Tang Jia Ju , Wang Jin , Pan Chang Jiang , Weng Ya Jun , Huang Nan
Published: March 2009

Three kinds of curcumin-loaded films (3wt%, 5wt%, 8wt%) were prepared using
poly(lactic acid-co-glycol acid (PLGA) as the carrier of curcumin, and studied. The result of Fourier
transform infrared spectroscopy (FTIR) and X-ray electron spectroscopy (XPS) show that the
curcumin is dispersed in the PLGA films. High performance liquid chromatography (HPLC)
analysis suggests that the release of curcumin can last 22-43 days. A fewer number of adhered and
activated platelets are observed on the curcumin-loaded PLGA films. The activated partial
thromboplastin time (APTT) increases for all curcumin-loaded films.
Preparation and Characterization of Porous Membrane for Drug Release
Authors: Lee Soo Young , Cho Young Ho , Youn Ju Yong , Kim Moon Suk , Lee Bong , Khang Gil Son , Lee Hai Bang
Published: March 2009

To develop osmotic granule with semi-permeable membranes, we prepared the semipermeable
membranes with different pore forming agent by using solvent casting method. The
membrane was consisted of cellulose acetate, Eudragit® RS, hydroxypropylcellulose (HPC), and
triethylcitrate (TEC) in the presence of PEG200, PEG1, 000, or dibutylsebacate(DBS) as a pore
forming agent. The produced membranes were white and elastic and exhibited soft property on
touch. The release amount of pore forming agent from membrane with different pore forming agent
was measured in water dissolution media and the order was PEG200 > PEG1, 000 > DBS. The
formation of pore in membrane was observed by morphological SEM image after dissolution. The
pore formation and porosity of membrane depended on water solubility of pore forming agent. We
confirmed that pores in porous semi-permeable membrane could be controlled by the pore forming
agent.
Supercritical Carbon Dioxide Assisted Impregnation of Molsidomine into Poly(DL-Lactide-co-Glycolide) for Sustained Release Applications
Authors: Ganapathy Hullathy Subban , Woo Min Hee , Hong Seong Soo , Lim Kwon Taek
Published: March 2009

Supercritical carbon dioxide (scCO2) was used as a processing medium for the
fabrication of drug encapsulated poly(DL-lactide-co-glycolide) (PLGA) monoliths for
their potential application in the controlled release of water soluble drugs. Exposure of
PLGA to scCO2 leads to effective plasticization and liquefaction due to the high solubility
and interaction of the scCO2 in the copolymer. By exploiting this property, it was
demonstrated that prolonged release formulations of molsidomine, a peripheral
nitrovasodilator used to treat angina pectoris, can be prepared by chemical solvent-free,
scCO2 assisted drug impregnation method. The in-vitro dissolution studies revealed that
the release rates of drug from the porous polymer monoliths containing different amount
of the drug samples were significantly retarded due to encapsulation of molsidomine into
the PLGA matrix.
A Novel Branch-Type PEGylation of Aptamer Therapeutics
Authors: Kang Hyun Gu , Park Jung Kyu , Seu Young Bae , Hahn Sei Kwang
Published: March 2009

We have developed a novel protocol to prepare a branch-type PEGylation for a long
acting formulation of aptamer therapeutics. A symmetric doubler phosphoramidite and the
following amine modified phosphoramidite synthon were introduced to the final sequence of antithrombin
aptamer, as a model for various aptamer therapeutics. The conventional linear PEGylation
reagents were conjugated to the terminal amine groups of oligonucleotide to prepare the branchtype
PEGylated anti-thrombin DNA aptamer. The PEGylated aptamer exhibited the improved
bioactivity to retard the occlusive thrombus formation in vitro.
Development of Micro-Patterned 2.5-D Scaffold Using Micro-End-Milling
Authors: Lee Han Ul , Kim Byung , Lee Seung Jae , Lim Geun Bae , Kim Sung Won , Rhie Jong Won , Cho Dong Woo
Published: March 2009

We fabricated micro-patterned 2.5-D scaffolds using micro-end-milling with controlled
pore and island sizes and interconnectivity to determine the effects of the micro-patterns on the cell
culturing process. Micro-end-milling can easily realize a high aspect ratio and accuracy, and can be
applied to various materials, including those that are biocompatible and biodegradable. Sixteen
types of micro-patterned scaffolds were designed and fabricated using the micro-end-milling
process. Fibroblasts were seeded and cultured to examine the viability of the developed micropatterned
scaffolds and their absorbed cell adhesion. The results confirmed that the fabricated
micro-patterns functioned successfully as scaffolds.
Wear Characteristics of Low Temperature Degradation-Free Zirconia/Alumina Composites in a Point Contact Condition
Authors: Lee Kwon Yong , Kim Hwan , Kim D.W. , Kim Dae Joon , Lee Myung Hyun , Seo Won Seon
Published: March 2009

The sliding wear of four different compositions of novel low temperature
degradation-free zirconia/alumina (LTD-free Z/A) composites were characterized in a ceramicceramic
point contact pair. The wear tests were performed by a pin-on-disk type wear tester in a
linear reciprocal sliding motion with a point contact in both dry and bovine serum lubricated
conditions at room temperature. For the dry sliding wear tests, AZ-2 (20 vol% (Y,Nb,Ce)-TZP/
80 vol% Al2O3) showed the best wear resistance among four kinds of LTD-free Z/A composites.
For the bovine serum lubricated sliding wear tests, wear was too little to be measured for all kinds
of Z/A composites. These novel LTD-free Z/A composites having excellent wear resistance
demonstrated a potential as the alternative materials for the ceramic- ceramic contact pairs of
femoral head and acetabular liner in total hip replacement.
A Comparative Study of Porous Titanium with Different Surface Modification Implanted in Dogs
Authors: Zhao Chao Yong , Li Hu , Yuan T. , Fan Hong Song , Zhang Xing Dong , Gu Zhong Wei
Published: March 2009

This study was carried out to investigate the effect of acid-alkali treatment and alkaliheat
treatment on the push-out strength and tissue response of the porous titanium in vivo. Porous
titanium with different treatment was implanted in dog bony site for 2 months and 5 months and the
push-out strength was tested. At 2 months, the mean push-out strengths of the acid-alkali treated
and alkali-heat treated porous titanium were 11.3 and 15 MPa, respectively. At 5 months, the values
reached 29.8 and 35 MPa, respectively. Histological observation showed a close contact between
implants and bone, and more bone tissue filled inside the pores of porous titanium increasing with
implantation time. The results indicated higher bonding strength between bone and porous titanium
in alkali-heat treated samples. Therefore, alkali-heat treatment can provide porous titanium implants
with better fixation as a bone substitute for clinical use under load-bearing conditions.
Topography and Wettability of Nanopatterned PMMA and PS Surfaces Embossed with Various Anodized Aluminum Oxide Nanotemplates
Authors: Kim D.H. , Shin Y.S. , Sun Kyung , Lee Kyu Back
Published: March 2009

The interactions between biological cells and nanometer-scale structured surfaces are
very important issues in nanobiotechnology. Most current methods of fabricating such surfaces are
costly and are not suitable for the production of a nanometer-scale structured surface that will be
used merely as a disposable tool in cell biological studies. We developed and optimized an
embossing method of polymers with nanoporous AAOs which is easy, cheap and fast in fabricating
nanometer-scale structures on the surface of polymers. We think this method can be applied not
only in cellular nanobiotechnogy but also in other areas of nanotechnogy.
Study of Rehabilitation of Injured Knee Joint Applying Chaotic Theory in Human Body Motion
Authors: Moon Byung Young , Son Kwon , Park Jung Hong
Published: March 2009

Gait analysis is essential to identify accurate cause and knee condition from patients who display
abnormal walking. Traditional linear tools can, however, mask the true structure of motor variability, since
biomechanical data from a few strides during the gait have limitation to understanding the system. Therefore,
it is necessary to propose a more precise dynamic method. The chaos analysis, a nonlinear technique, focuses
on understanding how variations in the gait pattern change over time. Healthy eight subjects walked on a
treadmill for 100 seconds at 60 Hz. Three dimensional walking kinematic data were obtained using two
cameras and KWON3D motion analyzer. The largest Lyapunov exponent from the measured knee angular
displacement time series was calculated to quantify local stability. This study quantified the variability
present in time series generated from gait parameter via chaos analysis. Gait pattern is found to be chaotic.
The proposed Lyapunov exponent can be used in rehabilitation and diagnosis of recoverable patients.