-
Article type: Cover
Pages
Cover1-
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Article type: Appendix
Pages
App1-
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Article type: Appendix
Pages
App2-
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Article type: Appendix
Pages
App3-
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Article type: Index
Pages
Toc1-
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Koji YAMAMOTO, Yasuji HARADA, Masaaki NAKAJIMA, Shigeyuki WAKITANI, Na ...
Article type: Article
Session ID: 339
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper describes a tissue-regenerating model using a cellular automaton for Bio-environment designing. The model consists of identical cells which mechanically connect with each other. The mechanical relation state of each cell is calculated using FEM. The local rules are "death" which is induced by apoptosis, "birth" and "transition". In this model, each cell means not "cell" but tissue which have the information of an adapted function for the mechanical environment. The morphology and the function constructed by this model were formed autonomically through the way of selection on the mechanical environment. Results of in-vivo testing using ES cell transplantation were used as reference of this model.
View full abstract
-
Shigeo WADA, Yixiang FENG, Ken-ichi TSUBOTA
Article type: Article
Session ID: 340
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Hemodynamics stresses are known to be able to degenerate the arterial wall and be involved in the pathogenesis of aneurysm formation and development. The present study numerically simulates the formation and growth of an aneurysm arising from a curved artery focusing on the interplay between the wall shear stress, arterial wall degeneration and deformation. It was hypothesized that if the local wall shear stress is higher than a threshold value, the Young's modulus of the wall is decreasedat'a fixed rate. The computer simulations clearly show the relationship among the change in the shape of the blood vessel, distribution of wall shear stress, and the degeneration of vessel wall during the progression of aneurysm, providing us new insight into the mechanism of aneurysm formation and development.
View full abstract
-
Madoka OTAKE, Shigeru TADANO
Article type: Article
Session ID: 341
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The nucleus pulposus of lumbar intervertebral discs is composed of a solid phase which includes collagen and proteogrycan and a fluid phase which includes interstitial fluid. When an external load is applied to an intervertebral disc, interstitial fluid passes between the cells of the solid phase. Then, frictional force occurs and induces the macroscopic nonlinear viscpelastic behavior of a disc. In this study, we examined the biphasic behavior of the nucleus pulposus under uni-axial confined compression. Permeability, which explains the interaction between two phases, was estimated from stress-relaxation behavior by using biphasic theory proposed by Mow V.C. et al. By modeling nucleus pulposus as biphasic material, we simulated the viscoelastic behavior of the intervertebral disc using a finite element analysis. In the relaxation process, the redistribution of the strain, change in the drag force and the relaxation stress could be observed by this simulation.
View full abstract
-
Yasuyuki Kurohara, itaru ishikawa, Yoshinori Sawae, Teruo Murakami
Article type: Article
Session ID: 342
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
It is known that the metabolism of articular cartilage is controlled by mechanical stimuli for chondrocyte. In this study time-dependent mechanical behavior in compressed articular cartilage was investigated by using finit element method based on biphasic theory. We examined the effect of strain-dependent permeability. It was shown that the peak stress decreases by treating permeability as a function of strain.
View full abstract
-
Takayuki KANAMORI, Kazuhiro FUJISAKI, Shigeru TADANO
Article type: Article
Session ID: 343
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Bone tissue is a composite material composed of hydroxyapatite (HAp) and collagen. As HAp particles in bone tissue are crystal structure, X-ray diffraction method can be used to measure the lattice strain of HAp. To estimate a stress in bone tissue from the lattice strain measured, it has to be found that a relationship between the lattice strain and macroscopic strain of bone tissue. This work presents a method to constitute an anisotropic bone model composed of HAp and collagen matrix. To make an optimal bone model, anisotropic elastic modulus was evaluated by comparing with actual elastic modulus of cortical bone in a shaft of bovine femur. The relationship between the strain of HAp phase and macroscopic strain of bone tissue was obtained from the optimal FEM model.
View full abstract
-
Emiko SHIMIZU, Kozaburo HAYASHI
Article type: Article
Session ID: 344
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Effects of DOCA hypertension on histology were studied in the rat carotid artery. Arterial segments were sliced-into thin ring specimens, and each structural component (collagen, elastin, nuclei of smooth muscle cells) was stained. The fraction and radial distribution in 4 layers of each component were analyzed with an image analzer. Hypertension uniformly increased wall thickness in all layers. However, it affected the distribution of components; for example, the area fraction of extracelluer matrix (collagen+elastin) increased in the inner most layer where stress increase developed by hypertension is larger than in the other layers. Althought the total number of smooth muscle cells in the media did not change, each cell was hypertrophied. There were almost no differences in these results between growing rats and mature rats.
View full abstract
-
Daisuke ITO, Sota YAMAMOTO, Tsuyoshi TANIGUCHI, Eiichi TANAKA, Koji MI ...
Article type: Article
Session ID: 345
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The relationship between tissue damage and changes of mechanical properties of. skeletal muscle with strain injury was discussed. Tibialis anterior muscle was extended 20, 25 or 30 % at 200 mm/sec to induce tissue damage. From pathological view points, severity of tissue damage could be classified into three grades and we could find a threshold of strain injury based on the relation between applied energy during injury-inducing process and the injury severity. We also evaluated the effects of strain injury on isometric contraction force. The results of biomechanical tests showed that the maximum contraction forces of 25%- and 30%-stretched muscles decreased. It indicates the injury severity could be related with biomechanical function of skeletal muscle.
View full abstract
-
Kota INOUE, Shoko SAZAKI, Shunji HIROKAWA
Article type: Article
Session ID: 346
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Tensile tests for fascicles, fascicle bundles and bone-ligament-bone units (BLB) all from swine Anterior Cruciate Ligament (ACL) and Posterior Cruciate Ligament (PCL) respectively were performed to compare the'results with each other. Two stress-strain curves of fascicles were derived. One was derived using the cross-sectional area at no load (Group N) and the other was done using the cross-sectional area at initial load (Group I). A stress-strain curve of fascicle bundles was derived using the cross-sectional area at no load. The results from the ACL showed that the tangent modulus of fascicle (Group I) was almost equal to that of BLB while that Group N was significantly low, indicating that ligaments may be constituted of tensed fascicles. While the results from the PCL showed that the tangent modulus of the Group I were significantly lower than that of the BLB. Thus microscopic observations were performed to gain insight into the structural difference between the ACL and the PCL.
View full abstract
-
Junichi HADA, Mitiaki KOBAYASI, Junichi SIBANO, Yukio NAKATUTI
Article type: Article
Session ID: 347
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A bone structure is-a highly differentiated coupling tissue and alternatively grows or declines regarding to biological-and/or physiological environments. It is an important, subject in the bioengineering and practical needs to investigate the evaluation method of the mechanical properties of a bone and also to clear the mechanism of the correlation between the structure change of a bone tissue and the aging. In this paper, density and elastic modulus distributions of a bone tissue were analyzed via distributions of surface wave velocity and acoustic impedance of micro parts .of a bone tissue measured using a scanning acoustic microscope (SAM). As a result, the elastic modulus of the canine femur bone showed a little anisotropy.
View full abstract
-
Takayuki IWATA, Makoto SAKAMOTO, Jun SAKAI, Takanori SHIGENO, Humikazu ...
Article type: Article
Session ID: 348
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this paper, the nanoindentation technique is applied to mechanical property estimation of bone with osteon and microstructures at the micron scale. The specimens were prepared from fresh pig femurs. The elastic modulus and hardness are directly calculated from the characteristic curve for the indentation load-displacement. The nanoindentation test applied to this study shows that the hardness and elastic properties of femoral cortical bone in the longitudinal direction are significantly dependent upon the osteon location in the cortical specimens.
View full abstract
-
Yoshinori KOYAMA, Taiji ADACHI, Yoshihiro TOMITA
Article type: Article
Session ID: 349
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Mechanical and biological factors affect regeneration process of trabecular bone structure in cancellous bone defects. Basic understanding of these factors will help us in designing artificial joints and implants and scaffold microstructure for bone tissue regeneration. In this study, artificial defect was created in cancellous bone region of a rat distal femur, and a formation process of trabecular structure in the defect was evaluated using X-ray μCT images in terms of a relation with mechanical and biological factors. As a result of experiment using a pin with a slit of three different shapes, it was shown that mechanical factors may not direct influence the early stage of trabecular bone regeneration, but biological factor may have remarkable influence on the process.
View full abstract
-
Tomohiro KOSAKI, Koji YAMAMOTO, Hidetaka OKADA, Yusuke MORITA, Tamada ...
Article type: Article
Session ID: 350
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The mechanical functions of regenerated cartilage are expected to be equivalent to those of natural cartilage. Articular cartilage keeps sliding with low friction over changes in the mechanical environment. In this research, we have investigated lubrication properties of regenerated cartilage with fibroin-sponge over changes of applied load. The frictional experiments showed that friction coefficient of regenerated cartilage increased with sliding distance due to exudation of proteoglycan near the surface, and in such state the friction coefficient decreased with the increase of applied load. The results suggested that the transitions of friction coefficient with the increase of applied load mainly depend on the behaviour of proteoglycan to changes of the pressure.
View full abstract
-
Nahoko YASUI, Kyoji HARADA, Naohide TOMITA, Takashi USHIDA, Yoshiaki W ...
Article type: Article
Session ID: 351
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
-
Daisuke UEDA, Katsuya SATO, Taiji ADACHI, Masaki HOJO
Article type: Article
Session ID: 352
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Many studies have reported that osteoblastic cells can sense the mechanical stimuli that result in rise in the intracellular calcium ion concentration as one of the cellular responses. However, the mechanical conditions, such as stress or strain, that induce the calcium signaling response are not clearly understood yet. In this study, we prepared osteoblastic cells with labelled cellular membrane and intracellular calcium ion using two fluorescence indicator, dyes. Localized deformation was applied to a single cell by direct indentation of a glass microneedle. Subsequently, initiation of calcium signaling response and deformation of cellular membrane were simultaneously observed. Obtained results suggested that the initiating point of localized calcium signaling response was located at the front area of the microneedle tip sliding. In the surrounding area of the needle tip, it could be imagined that there was localized and complicated strain distribution. Therefore, as a future study, the experiment with improved time- and spatial-resolutions is necessary.
View full abstract
-
Yusuke FUKUDA, Noboru IGARASHI, Koji YAMAMOTO, Naoyoshi KACHI, Yasushi ...
Article type: Article
Session ID: 353
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
It is important to clarify the adhesion phenomenon to determine initial state of tissue formation. In this study, a new scaffold is proposed and adhesion properties between the scaffold and cell were measured. Mechanical adhesion force of single cell was measured using micro machine.
View full abstract
-
Shogo NISHIJIMA, Katsuya SATO, Taiji ADACHI, Yoshihiro TOMITA
Article type: Article
Session ID: 354
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The cytoskeletal actin structure is dynamically reorganized in various cellular activities such as cell movement and cytokinesis. In addition, the change of mechanical environment also induces the reorganization of the actin structure. The aim of this study is to clarify the reorganization mechanism particularly focusing on the organizing process of actin fiber structure. Firstly, actin fiber structure is completely disassembled by Cytochalasin D treatment. After the treatment, re-assembling process of actin structure was observed. Actin fibers in living osteoblastic cells were fluorescently labeled using the transfection technique of EGFP-actin fused protein DNA. And, dynamics of cellular membrane and actin cytoskeleton was visualized using fibronectin-coated microparticles that adhered onto the cellular membrane. From the observed results, in the initial phase of the re-assembling, actin fibers were formed to connect between the microparticles and the cell nucleus. Subsequently, microparticles moved along the formed fibers toward the nucleus. Therefore, it can be predicted that not only fibronectin but also structures surrounding the cell nucleus guides the actin fiber assembly and that cell membrane is moving along to actin fibers.
View full abstract
-
Shinji Deguchi, Toshiro Ohashi, Masaaki Sato
Article type: Article
Session ID: 355
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this paper, mechanical architecture of adherent cells such as endothelial cells was discussed based on experimental evaluation of mechanical properties of subcellular structural components. Tensile properties of single stress fibers, bundles of actin filaments, in endothelial cells were obtained with in vitro micromanipulation. Preexisting tension in the stress fibers was then evaluated from the tensile properties and preexisting strain. Physiological tension level of the stress fibers was found to be 1-10 nN order of magnitude, which was "comparable to that of the traction force applied by adherent cells at their focal adhesion sites. Electron micrograph showed a possibility of the nucleus and membrane-bound organelles in endothelial cells as an intracellular compressive stress-bearing element. These results proposed that force balance between the organelles would be a major determinant of cellular morphology and force transmission in the cytoplasm.
View full abstract
-
Takahiro SHIRONO, Kazuaki NAGAYAMA, Takeo MATSUMOTO
Article type: Article
Session ID: 356
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We have investigated the circumferential heterogeneity of the smooth muscle (SM) contraction in this artery wall from two viewpoints. From a macroscopic viewpoint, we measured the deformation of the artery wall following SM contraction in four circumferential positions to find that the ventral section contracted more than the dorsal (P<0.005). From a microscopic viewpoint, the SM cells were isolated from the ventral and the dorsal regions by enzymatic digestion to compare the contractility of the cells obtained from the different circumferential positions. All cells isolated from the ventral side become shorter than 40μm upon contraction, while about 8% of the cells obtained from the dorsal side remained elongated even after the stimulation with 10^<-5>M norepinephrine. These results may indicate that 1) the population of the smooth muscle cells is heterogeneous; 2) less contractile cells reside in the dorsal side of the aortic wall, causing the circumferential heterogeneity, in the contraction.
View full abstract
-
Noritaka YAMAMOTO, Daisuke Sugahara
Article type: Article
Session ID: 357
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The fascicles obtained from mouse tail tendons were immersed in a collagenase solution, and collagen molecules in the fascicles were decomposed. These specimens were stretched to failure. Decomposition of collagen molecules decreased the tensile strength and strain at failure.
View full abstract
-
Kyohei Iida, Kazuhiro FUJISAKI, Shigeru TADANO, Jun-ichi SHIBANO, Naok ...
Article type: Article
Session ID: 358
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Bone tissue is a composite material composed of hydroxyapatite (HAp) and collagen. As HAp particles in bone tissue are crystal structure, X-ray diffraction method can be used to measure the lattice strain of HAp. This work shows the relationship between lattice strain of HAp crystals and macroscopic strain of bone tissue. The strip specimens of30×6×0.8mm in size were cut from cortical bone in a shaft of bovine femur. The long axis of the specimen was aligned with the bone axial and tangential direction. A tensile device was developed to apply tensile load to the specimen during the X-ray irradiation. Macroscopic strain was measured by a strain-gage glued on the surface of the specimen. Lattice strain of HAp in the specimen was measured by the X-ray diffraction method. As a result, the relationship between applied macroscopic strain and lattice strain was found to depend on Young's modulus of bone tissue.
View full abstract
-
Takanori SHIGENO, Takatoshi UMENO, Toshiaki HARA
Article type: Article
Session ID: 359
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The various studies have been reported about the compressive deformation behavior of trabecular bone under load applivation. However, it is less than clear how fracture properties of bone is related to trabecular structure. The purpose of this paper is to study the relationship between furacture property and trabecular bone structure under compressive load application. A special-designed appratus applicable to the compression test in a micro computed tomography system (μ-CT) was used. The specimens under compression load in steps were scanning in the μ-CT. As a results, there may be no significant difference in the connectivity property of trabecular bone specimens.
View full abstract
-
Kosaku KURATA, Junpei MATSUDA, Hiromasa MIURA, Yukihide IWAMOTO, Hideh ...
Article type: Article
Pages
43-44
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Bone is continuously subjected to repetitive loading, which leads to microdamages even if the strain level is within physiological range. The damaged site must be promptly removed by a remodeling mechanism that is targeted to microdamages; otherwise, the accumulation of damages induces bone fracture. In this study, we investigated the mediators, by which osteoclastic bone resorption could target to the damaged site. As a result, TRAP-positive cells were differentiated from bone marrow cells that co-cultured with mechanically damaged mice calvariae. Additionally, marrow cells showed a significant increase in TRAP positivity when they were cultured in conditioned medium collected from mechanically damaged osteocytes. These experimental findings indicated that soluble factors secreted by the damaged osteocytes would have a potential to induce osteoclast-like cell formation, and consequently target bone resorption to the damaged site.
View full abstract
-
Atsushi SHIRAI, Ryo FUJITA, Toshiyuki HAYASE
Article type: Article
Session ID: 422
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Neutrophils are known as the most popular cells in leukocytes. They retain in pulmonary capillaries even in normal lungs causing 40- to 80-fold higher concentration than in systemic large vessels. The highly concentrated neutrophils are recruited to inflammations for the host defense. Therefore, it is essential to know their flow characteristics in the pulmonary capillary bed for the understanding of the immune system in lungs. For that purpose, authors have investigated the flow of a neutrophil in single capillary segment, and developed a mathematical model to simulate the flow of neutrophils in a capillary network. In this research, effect of the cell stiffness on the distribution of transit time of the cells is investigated. The result shows that the median of the transit times is longer than the average value for all the three levels of cell stiffness.
View full abstract
-
Akihiro SOETA, Takuji KOIKE, Kyouji HONMA
Article type: Article
Session ID: 423
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The efficiency of the sound transmission of a bone-conduction hearing aid is improved when tooth is excited by a transducer because the vibration generated by the transducer is not attenuated by the damping of skin and directly transmits to the skull. In addition, if sound localization is established by a binaural bone-conduction hearing aid, speech articulation is also improved. In this study, the sound localization was tested by applying sinusoidal signals to two transducers attached to right and left teeth. The pattern of the sound localization according to the phase difference between the two signals depended on individuals, and this sound localization seemed to be caused by the change of the amplitude of the vibration transmitted to the cochleae from the transducers.
View full abstract
-
Sunao MASUDA, Atsushi SHIRAI, Toshiyuki HAYASE
Article type: Article
Session ID: 424
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Neutrophils retain in pulmonary capillaries causing 40- to 80-fold higher concentration than in systemic large vessels in normal lungs. The highly concentrated neutrophils are effectively recruited to inflammations for the host defense. Therefore, it is important to know the flow characteristics of neutrophils in pulmonary capillary bed for the understanding of the immune system in lungs. In previous studies, flow of a neutrophil through a narrow capillary was investigated numerically to develop a mathematical model. It is indispensable to evaluate the accuracy of the model. In this research, an observation system of flow of blood cells in microchannels is constructed, and the cell velocities are measured. Neutrophils don't pass through the channel under the pressure control. Erythrocytes pass through it under the flow rate control, and their velocities are measured to show that the velocity profile along their loci varies with the cell orientation entering the channel.
View full abstract
-
Kotomi SAITO, Toshiyuki HAYASE, Atushi SHIRAI
Article type: Article
Session ID: 425
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Precise frictional characteristics of the red blood cells (RBCs) have not been understood. Hayase et al. developed the inclined centrifuge microscope, and the frictional characteristics of RBCs on a glass plate were measured at the first step. In that research, it was the subject of discussion whether the cells glide or roll on the glass plate since the resolution of the microscope was not sufficient to distinguish the cell motion. This report deals with improvement of the observation technique for cell motion. At first, the magnification of the inclined centrifuge microscope is increased by 5 times. The shape of RBCs under movement can be seen clearly and cells seem to glide on the glass plate. However, it is still difficult to exclude the possibility of cell rolling. So authors investigated microbeads as the indicator of cell motion. It revealed that ordinary microbeads are too small to observe, and they don't adhere to RBCs.
View full abstract
-
Yutaka TAMURA, Sayuri MURAKAMI, Takuji KOIKE, Kyoji HOMMA
Article type: Article
Session ID: 426
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Experiments were carried out to investigate the acoustic emission (AE) response in plant of Acer Palmatum Var. Matsumurae exposed two and six days to ozone environment. AE sensors were put onto the upper and lower stem of the plant in the greenhouse. AE incidence per twelve hours and some characteristic of AE were considered and the correlation of AE with stomata conductance was investigated. Explicit increase of AE in ozone exposure and decrease of AE after ozone exhaustion were observed during ozone exposure period as well as stomata conductance.
View full abstract
-
Toru HANZAWA, Toshiyuki HAYASE
Article type: Article
Session ID: 427
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The principle of heart massager is applied to develop a new implantable cardiac supporting device that pushes the heart from outside to enhance the blood circulation only when it is needed. In order to use this devise clinically, this study aims to establish the methodology of the optimum design of its geometry and operating condition through numerical simulatioa As the first step, present report deals with development of the lumped parameter model of the systemic cycle of the cardiac system. Numerical solution was obtained with standard Runge-Kutta method. The solution qualitatively describes the dynamic characteristics of the system including essential information for the optimum design of the supporting devise, such as the power consumption and the energy of the cardiac motion. Furthermore, simulation was performed for a disabled heart to understand the effect of the parameter of the heart on the total blood flow.
View full abstract
-
Takayuki YAMAGATA, Kenichi Funamoto, Toshiyuki HAYASE
Article type: Article
Session ID: 428
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Detailed information of the velocity and pressure field of the blood flow is essential to establish an advanced diagnosis and treatment of serious circulatory diseases. Commonly used medical measurement equipments cannot measure such information, while even state-of-the-art numerical simulation cannot reproduce real blood flow accurately. In order to overcome this problem, the authors have proposed a new technique, Ultrasonic-Measurement-Integrated (UMI) simulation, that integrates ultrasonic measurement equipment and numerical, simulation, and revealed its usefulness by numerical simulation. The present report describes the development of fundamental procedure of the interface between ultrasonic equipment and simulation, and acceleration of computational speed for real time operation. By considering the tolerance of the solution, computational speed has been accelerated by a factor of 90 achieving only ten times longer computational time than real phenomena.
View full abstract
-
Kosaku KURATA, Hidehiko HIGAKI
Article type: Article
Session ID: 429
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Fluid shear stress caused by mechanical loading plays an important role in regulation of bone remodeling. Osteocyte is exposed to the fluid flow inside bones, and therefore considered to be the most promising cell that provides a cellular basis for mechanosensing. In order to determine the role of osteocyte, functional responses to fluid shear stress were investigated in osteocyte-like cell line MLO-Y4 culture. A tapered cone was rotated on the medium-filled culture plate, generating continuous laminar fluid flow over the cells. The application of fluid shear stress reoriented the cells so that they aligned with the direction of fluid flow, which indicated the induction of cytoskeletal reorganization. Additionally, nitric oxide (NO) release and expression of cyclooxygenase-2 (COX-2), the key enzyme for prostaglandins production, were enhanced in the fluid-sheared cells. These findings may reveal the mechanism by which osteocyte senses mechanical loading and regulates osteoclast and/or osteoblast functions.
View full abstract
-
Shunsuke MIYAUCHI, Katsuko FURUKAWA, Yoshikazu UMEZU, Yasuyuki OZEKI, ...
Article type: Article
Session ID: 430
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Vascularization is an essential phenomenon for implanted cells to proliferate, and "differentiate. We developed a sheet-like bone graft model composed of human bone marrow stromal cells (HMSCs), and beta tricalcium phosphate (beta TCP) porous beads. By combining multilayered cell-bead sheets and collagen gel, we fabricated bone implants having the space for angiogenesis, and subcutaneously implanted them in nude mice. From the result of implantation, neovascularization reaching to the central area of the graft was recognized. Osteogenesis was also observed near the surface of graft. Therefore, the newly designed implant seemed to have a high osteoconductive activity. This result would suggest a new style of bone graft, which is designed on the premise of vascularization.
View full abstract
-
Masami IWAMOTO, Eiichi TANAKA, Kohei DENDA, Sota YAMAMOTO
Article type: Article
Session ID: 431
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Constitutive equations and a damage evolution equation of cortical bone were formulated to predict bone fractures and their patterns accurately in traffic accidents or falling. The constitutive equations can represent characteristic features of cortical bone, such as elasticity with strain rate dependency, viscoplasticity, and strength anisotropy as well as strength asymmetry of tension and compression. The damage evolution equation can simulate damage accumulation of cortical bone with rate dependency. Experimental data of uniaxial compressive and tensile loading tests of human cortical bones were used to validate these equations. Predicted stress-strain curves and failure points agreed well with those of experimental data at wide range of strain rates. This shows the present model can be used to predict bone, fractures in various impact situations of traffic accidents or falling.
View full abstract
-
Ayumi SAKAMOTO, Tatsuro IKEGAMI, Yoshinori SAWAE, Nobuo SAKAI, Yasuyuk ...
Article type: Article
Session ID: 432
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
In this study, it was investigated how mixture-ratio, cement-thickness, and loading-cycle would affect retentive-force of the dental-cement by using the cyclic-load-tester. The used cyclic-load-tester is designed based on the past reference, to simulate digestion movement. The result showed that the retentive-force failed by the increase in a mixture ratio. However, the correlation between retentive-force and cement-thickness was not clear. Moreover the retentive-force was reduced with the increase in the number of the loading-cycle. It can be considered that these results obtained from this simulation are useful for evaluation of clinical phenomena.
View full abstract
-
Jun SAKAI, Fumikazu KODA, Makoto SAKAMOTO, Koichi KOBAYASHI, Toshifumi ...
Article type: Article
Session ID: 433
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Nanoindentation test results, reveled mechanical properties that are directly related to the local structure of the tooth. In this study, nano-hardness and nano-elastic modulus of human molar teeth were studied across the dentin-enamel junction (DEJ). Specimens were obtained from seven molar permanent teeth. Nano-hardness and nano-elastic modulus both decreased towards the DEJ. It is found that the nano-mechanical property profiles across the DEJ were due to a continuous variation in the ratios of relative amount of enamel and dentin. This result suggests that the DEJ displays a gradient in structure and that nanoindentation method show promise for further understanding its structure and function.
View full abstract
-
Tatsushi TOKUYASU, Akito ICHIYA, Tadashi KITAMURA, Genichi SAKAGUCHI, ...
Article type: Article
Session ID: 434
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
This paper describe a simulation tool for estimating pre- and postoperative cardiac functions for a diseased heart due to myocardial infarction. Cardiac function is able to be evaluated obviously by a pressure-volume (PV) loop including Emax, computed based on FEM. For a normal model, a left ventricular finite element model is built from patient's cine CT images. It is assumed that the ventricular wall of the model is of one-layer, elastic and isotropic. An infarcted region set up for the left ventricular wall with abnormal Young modulus is removed to estimate the postoperative cardiac function in terms of PV loop. In our simulation, realistic trends of a PV loop are computed. The method of its online use using a multidimensional spline interpolation is presented.
View full abstract
-
Katsuaki TANIMURA, Sadayuki UJIHASHI, David Nash, Bill Dempster
Article type: Article
Session ID: 435
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The purpose of this paper is to investigate the condition of the stent deployed into the artery. The finite element contact simulation between the stent and the artery is developed in this research. The stent is made of nitinol, which has shape memory effect and superelasticity. The cross-sectional area of the stent is considered to be an interruption factor for the blood flow. Therefore, the evaluation parameter with respect to the cross-sectional area is defined. As a result, it is confirmed the simulation is useful for the stent design.
View full abstract
-
Kazuhiro MARUYAMA, Koji MORI, Takashi SAITO
Article type: Article
Session ID: 436
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Stent performance can be evaluate the sum of radial-force and bending-stiffness. These mechanical properties depend on stent structures (for examples, longitudinal length of cell and link). The objective of this paper was to investigate the influence between longitudinal lengths of cell (A) and link (B) and these mechanical properties using numerical analysis. Cell-link-cell model was developed, because stent consists of repeat structure. As results, both radial-force and bending-stiffness curve with B/A were quadratic curves. Stent total performance, which was defined as the sum of radial-force and bending-stiffness, was superior and fluctuated a little in 0.5-1.0 of B/A.
View full abstract
-
Koji MORI, Kazuhiro MARUYAMA, Takasi SAITO
Article type: Article
Session ID: 437
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
High radial stiffness and longitudinal flexibility are essential mechanical properties of a stent. A stent consists of cell and link, which is minimal structure unit. Mechanical properties of a stent are depended on these configuration and dimension. In this paper, the relation between mechanical properties and the longitudinal length of cell and link was investigated. Six stents were constructed and measured the bending stiffness using 4-points bending test machine. The result showed that the bending stiffness decreased with the cell-link length ratio (B/A). The result was-not consistent with the numerical analysis. The disagreement suggests that the deformation mode under bending condition changes with B/A.
View full abstract
-
Daisuke SEKIHARA, Jiro SAKAMOTO, Teruhisa YAMASHIRO, Keisuke SAKURAKIC ...
Article type: Article
Session ID: 438
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
External fixation method has been applied to fixation of bone fracture and distraction osteogenesis for the case of malignant bone tumor or failures to bone thrive. During of distraction osteogenesis, callus has to be kept elongation by manipulation ,of the external fixator. Mechanical performance of the external fixation device is important to get success of the distraction osteogenesis. Moreover, mechanical property evaluation of the bone repairing part is important to decide a period of removing the external fixator. In this study, evaluation technique of the mechanical property of callus using strain measurement on fixation device was proposed. Finite-element models of two types external fixation device, which were Ilizarov and Taylor type device, were created assuming the device attached to a tibia with callus. Change of strains at fixation wires were analyzed with varying Young's modulus of the callus. Effectiveness of the evaluation method based on strain measurement of external fixator was discussed from the results.
View full abstract
-
Toshihiko SHIRAISHI, Shin MORISHTTA, Takahiro YAGI, Kunito HOSHINO, Mo ...
Article type: Article
Session ID: 439
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Though mechanical stimulation is known as one of important factors promoting bone generation, the most effective frequency on it has not been specified yet. In this paper, we have investigated effects of mechanical vibration on promoting growth of MC3T3-E1, which is one of mouse calvaria osteoblast-like cell lines, and tried to specify the most effective frequency. The cells are cultured under sinusoidal vibration for 24 hours a day, 28 days at frequency of 12.5 or 100 Hz, setting an acceleration amplitude as constant of 0.5 G The cell density of the vibrating groups has been higher than that of the non-vibrating group after 14-day cultivation by counting the cells and checking their morphology through an optical microscope. The amount of generated calciumsalts in the vibrating groups is shown more than that in the non-vibrating group using alizarin red S stain solution on 28-day cultivation. It is found that the bone generation has been promoted by the mechanical vibrating stimulation.
View full abstract
-
Eijiro MAEDA, Tomokazu KAI, Harukazu TOHYAMA, Kazunori YASUDA, Kozabur ...
Article type: Article
Session ID: 440
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
The central third of the patellar tendon is a common substitute for anterior cruciate ligament reconstruction. Previous studies have shown that the mechanical strength of the tissue regenerated in the central defect of the patellar tendon increased with time, but that the strength of surrounding, residual tendon tissue decreased, followed by progressive recovery. However, effects of aging on the mechanical properties of such healing tissues remain unknown. In the present study, we investigated this issue using the patellar tendon of age-different rabbits: 2 and 3 months, and 2 years. Tensile tests were carried out at 3 and 4 weeks (2- and 3-month old), and 6 and 12 weeks (2-year-old) after the resection of the central portion. The mechanical properties of regenerated tissues seemed to be better at higher ages, and the recovery of residual tissues was delayed with age.
View full abstract
-
Ko KITAHARA, Ko TAKANO, Kazuhiro HASEGAWA, Toshiaki HARA
Article type: Article
Session ID: 441
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
A comparison of pressure change in adjacent lumber intradisc after medial facetectomy, Graf ligamentoplasty (Graf), and pedicle screw fixation (PS) is made to clarify the mobile influence of the spinal instrumentation on the adjacent segment. The fresh porcine lumbar spines (L3-L6) with destabilized segment (L4-L5) were used to estimate the difference on the intradiscal pressure in each instrument. It is found from the intact segments that the intradiscal pressure increased with flexion and decreased with extension. The highest pressure for each case is measured under maximal flexion. For the stabilized segment with Graf system, the pressure in L4/5 intradisc is significantly higher under neutral position while the pressure increases during flexion. After Graf and PS, it is found that the pressure in L3/4 intradisc increased. The results may show that the influence of Graf on the adjacent segment seems to be more significant than that of PS.
View full abstract
-
Tatsuya OYAMA, Hiroyuki SEGAWA, [in Japanese], Toshiaki HARA
Article type: Article
Session ID: 442
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
Soft-tissue including ligament has a very complex anatomy which enables it to perform an important role in guiding the most suitable operation for total knee arthroplasty (TKA). A new device was designed and built to test the mechanical equilibrium the tensile properties of the soft-tissue and to asses the gap difference between tibial plate and component using the pressure sensors. It is shown from the experimental results that the applicability of a special-designed device to the optimum operative for TKA may be significantly sufficient.
View full abstract
-
Toshimitsu Hirai, Thuyoshi MIKAMI, Hisashi HAYASHI
Article type: Article
Session ID: 443
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We developed the laser stimulation equipment using the laser beams of two different wavelength. That we developed this equipment developed in order to control the nervous system of a living body and to control a pain. We experimented in stimulus medical treatment to 22 old folks who live in Shizuoka Prefecture using this equipment. Moreover, we conducted the experiment which finds the effective stimulating point (deep tissues during acupuncture) of a living body. And we added the electric stimulus to this stimulating point, and observed the reaction of a living body by brain waves. We report the result of these experiments.
View full abstract
-
Ichiro KITAYAMA, Kiyohiro OMORI, Hirofumi MATSUNO, Yoshimi SUGIMOTO
Article type: Article
Pages
89-90
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
CONFERENCE PROCEEDINGS
RESTRICTED ACCESS
We surveyed wondering prevention and monitoring system at geriatric health care facilities for the elderly, geriatric medical care facilities for the elderly, and group homes in order to develop new wandering prevention and monitoring systems which prevent persons with dementia from falling down beside a bed and other accidents in inside or outside of facilities. First of all, we drew up a questionnaire and sent them to welfare facilities for elderly (N=342) in Hyogo prefecture. 108 facilities returned questionnaires to the Hyogo Assistech, and we checked them up. 56 % facilities installed one or some systems. 57 % of systems are monitoring cameras, 21 % are tag sensor systems, 21 % are infrared rays systems.
View full abstract
