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Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Article type: Appendix
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Article type: Index
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A1-A8
Published: August 02, 2008
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Yutaka NAKAYAMA, Ei YAMAMOTO
Article type: Article
Session ID: 743
Published: August 02, 2008
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It is well known that microdamage is induced by in vivo stresses applied to bone tissues. Such microdamage is closely related not only to fatigue or stress fracture but also to bone homeostatic response. In order to gain basic insight into adverse effects of overloading on bone strength, in the present study, we observed bone microdamage induced by monotonic non-destructive overloading. Cylindrical cores obtained from bovine cortical bone were used for the experiment. Bone specimens were cyclically loaded between 0 and 10 N for the determination of the initial modulus (E_0) which is used to normalize the applied stress (σ) in loading tests. We monotonically applied a normalized compressive stress (σ/E_0) of 0.05 to specimens. Following the mechanical loading, microdamage was stained using a sequence of fluorochromes (alizarin and calcein) that allows differentiation of damage due to overloading. Microdamage observation was carried out using an epifluorescence microscopy. The results obtained show that non-destructive overloading induced linear microcracks and diffused damage area in bone tissues.
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Yusuke IMARI, Masahiro TODOH, Shigeru TADANO
Article type: Article
Session ID: 744
Published: August 02, 2008
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Bone is a composite material composed of mineral matrix (mainly hydroxyapatite) and organic matrix (mostly type I collagen) in a microscopic scale. Macroscopic mechanical properties of bone are dependent on the structure and mechanical properties of these microscopic constituents. It has been considered that bone density is a predictor of its strength from a macroscopic perspective, but denaturation of the organic matrix would also lead to a significant loss of bone strength. In this study, heat-treated bone was examined as a collagen denatured model, and then 4-point bending tests and impact tests were conducted to assess the role of the collagen matrix for mechanical properties of bone. As a results of 4-point bending test, the cortical bone specimens heated at over 150℃ failed with a low strain in the elastic region, suggesting a brittle fracture behavior. The elastic modulus of bone was slightly reduced with the heating temperature, whereas the bending strength significantly decreased, especially at 150℃. The results of the impact test shows heat-induced collagen denaturation has great influence on the toughness of bone. These results suggests that not only denatured collagen molecules but also cleaved peptides and/or damaged collagen cross-links play an important role on the mechanical properties of bone.
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Shigeru TADANO, Masahiro TODOH, Kazuhiro FUJISAKI, Masaki KATO
Article type: Article
Session ID: 745
Published: August 02, 2008
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The purpose of this study is the elucidation of electro-mechanical response of spinal cord tissue. Spinal cord tissue is composed of white matter, gray matter, spinal meninges and water. The tissue has triphasic construction consisting of solid phase, fluid phase and electric reactions. Solid phase contains negative charged proteoglycan which enhance swelling pressure and exerts an influence on the tissue behavior. On the other hand, strain increases fixed charge density relating to electric potential gradient and streaming potential. We conducted the confined compression tests on spinal code specimens cut out from both white matter and gray matter. Ag/AgCl electrodes were used to measure the electric potential change on each specimen deforming in physiological saline. The streaming potential measurements were performed under compression, cyclic loading and ramp/stress-relaxation displacements. The measured potentials were correlated well with strain and stress. In the compression/stress-relaxation test, linear relation was confirmed between the stress and streaming potential with constant value of electrokinetic coefficient ke used in triphasic theory. Streaming potential was detected in each loading condition and the value varied in different tissue.
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Nobuo Sakai, Sho Tokunaga, Natsuko Hosoda, Yoshinori Sawae, Teruo Mura ...
Article type: Article
Session ID: 746
Published: August 02, 2008
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The purpose of this study is to analyze the compressive behavior of articular cartilage in confined compression. Articular cartilage realizes very low friction and long durability in synovial joint. So, the mechanism and functional behavior of articular cartilage has been observed by many researchers for the insights of arthritic disease, regenerative medicine, and new tribological design. Articular cartilage has high water content of nearly 80% and behaves as biphasic material. To observe the mechanical behavior of articular cartilage, authors developed micro testing machine, which equipped on microscope and had the ability to visualize the strain in tissue. In this report, we constructed a confined compression chamber for the cartilage test piece, and compared the mechanical behavior between unconfined and confined compression. The morphology of subcondral bone was also observed from the view point of fluid transport.
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Junpei MATSUDA, Kosaku KURATA, Takanobu FUKUNAGA, Hidehiko HIGAKI
Article type: Article
Session ID: 747
Published: August 02, 2008
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Bone loss during spaceflight or prolonged immobility has been attributed, in part, to a reduction in osteoblast number, altered gene expression, and an increase in cell death. Specially, osteocyte which is considered to be a mechanosensing cell could deeply participate in this process. To test the hypothesis that osteocyte induces osteoporotic bone loss and negatively regulated bone remodeling, we created a novel system to simulate spaceflight microgravity combining control and experimental cells within the same in vitro environment. Recently, we found that osteocyte-like cell line MLO-Y4 cells significantly induced TRACP-positive cells under microgravity. This study was to examine the role of osteocyte in bone marrow cell differentiation, especially the effect of M-CSF and RANKL secretion on bone marrow cell differentiation. MLO-Y4 was subjected to microgravity for 24 hours with and without M-CSF and RANKL inhibiter. The M-CSF and RANKL secretion in the conditioned medium was assayed by ELISA. Furthermore, supernatants of MLO-Y4 culture were collected, and then added into bone marrow cell culture. After a week of culture, TRACP activity was colorimetrically quantified. As a result, Microgravity exposed osteocytes secreted M-CSF and RANKL. Additionally, this increased TRACP activity was suppressed by inhibition M-CSF and RANKL. The data suggested that microgravity could influence anomaly osteoclastic cell differentiation by modulating M-CSF and RANKL expression in osteocytes.
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Yusuke KAMBE, Koji YAMAMOTO, Katsura KOJIMA, Yasushi TAMADA, Naohide T ...
Article type: Article
Session ID: 748
Published: August 02, 2008
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RGDS-transgenic fibroin scaffold have been expected to be one of the useful materials for cartilage regeneration where chondrocytes can synthesize matrix to improve lubricant function. For the purpose of seeking some aspects of the mechanism of interactions between a single chondrocyte and RGDS-transgenic fibroin substrate, adhesive force of a chondrocyte to the substrate was measured. It was found that the adhesive force of a chondrocyte on RGDS-transgenic fibroin substrate was higher than that on normal fibroin substrate between 3 and 12 h after seeding, while significant differences were not shown in cell spreading area. It could be considered that integrin expression and/or its distribution affected the adhesive force. Immunofluorescence staining for actin and vinculin showed that the cell morphology could be influenced by integrin-mediated signaling changes. These results suggested that initial cell-material adhesion have an important role to affect the formation of functional cartilage tissue.
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Seungwoo SIM, Naoyoshi KACHI, Yoshihiko KUWANA, Yasushi TAMADA, Naohid ...
Article type: Article
Session ID: 749
Published: August 02, 2008
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Aiming to observe and evaluate cell behaviors in porous scaffold such as fibroin sponge, we developed a novel method where cells are cultured on a patterned substrate containing an array of pits which mimics culture environment in porous scaffold. Rabbit chondrocytes were seeded on the patterned substrates coated with fibroin (Fib group) or collagen type I (Col group), and cell behaviors such as aggregation and adhesion in the pit were observed and quantified. The results showed that projection area of the cells in the Fib group increased along with culture period, while that in the Col group showed no significant change.
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Naohiro KUWAHARA, Ei YAMAMOTO
Article type: Article
Session ID: 750
Published: August 02, 2008
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To understand the mechanisms of the remodeling of tendons and ligaments, it is imperative to quantify the force environment in which these tissues are expected to expose in vivo. Because treatment of musculoskeletal injuries often includes immobilization and disuse of joints as part of the therapeutic regimen, the effects of stress deprivation on the biomechanical properties of tendons and ligaments are clinically important. Many investigators have measured in vivo force in tendon tissues during normal activity. However, few studies are performed to measure the force under stress-deprived condition. Therefore, rigorous relationships between stress reduction and remodeling remain unknown. In the present study, rat patellar tendons were unloaded by tail suspension or joint immobilization. We compared in vivo tension in the tendons under stress-deprived condition with the different methods. Whereas the peak tension under the normal condition was approximately 10.7 N, the peak tension of approximately 9.0 and 2.8 N was applied to the tendons under the condition of tail suspension and joint immobilization, respectively. These quantitative data would be essential to study the biomechanical response of tendons and ligaments to stress deprivation.
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Noritaka YAMAMOTO, Daichi MATSUO
Article type: Article
Session ID: 751
Published: August 02, 2008
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Tearing test was performed for the fascicles obtained from rat tail tendons. Tearing strength was defined as the tearing load divided by the tearing width of fascicles. The tearing strength of 9 specimens was 0.0878 ± 0.0320 N/mm (mean ± S.E.).
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Keita SUMIDA, Souichi SAEKI, Yu NAKAMICHI, Yoshitaro SAKATA, Takashi S ...
Article type: Article
Session ID: 752
Published: August 02, 2008
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Tendons and ligaments, which have hierarchical structures from nano to micro scale, should play an important mechanical role in motion functions. We proposed Optical Coherence Straingraphy(OCS), which can non-invasively detect the tissue strain distribution with micro scale by means of Optical Coherence Tmography(OCT). In this study, OCS was applied to rat tail tendons so as to evaluate the relationship between 3-dimensional tissue structures and micro-bio-mechanics. Consequantly, the uni-axis periodical strain distribution was revealed by OCS, corresponding to 3-dimensiona crimp structure observed by integrated OCT images.
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Yoshitaro SAKATA, Souichi SAEKI, Takashi SAITO, Takafumi HIRO, Masunor ...
Article type: Article
Session ID: 753
Published: August 02, 2008
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OCT is intrinsically difficult to estimate biomedical characteristics of tissue, because OCT images just show speckle patterns originated from back-scattering light from tissue. Authors proposed Optical Coherence Straingraphy (OCS), which could visualize tissue mechanical information, e.g. strain distribution, from OCT speckle deformation. OCS is based on Recursive Cross-correlation technique, resulting in provide displacement vector distribution with high resolution. Furthermore, Adjacent Cross correlation Multiplication is introduced as a speckle noise reduction method. Finally, Strain distribution was calculated using Weighted Moving Least Square Method to suppress the differential error from detection noise. However, it has not been experimentally verified exhaustively. In this study, experimental verification study on OCS was carried out using artificial blood vessels. In the experiment, and OCS detected tomographic strain distribution in the phantom bended by an indenter. Strain distribution was compared to numerically simulated results based on Finite Element Method. Consequently, both results are analogous in terms of strain pattern. It was confirmed that OCS could be effective to an assessment of atherio sclerosis, micro mechanical biopsy.
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Takahiro SHIRONO, Kazuaki NAGAYAMA, Takeo MATSUMOTO
Article type: Article
Session ID: 754
Published: August 02, 2008
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Arterial walls consist of structural components that have various elastic moduli: elastin, collagen, and smooth muscle cells (SMCs). Such difference in their mechanical properties may cause their heterogeneous deformation at a microscopic level in arterial tissue subjected to uniform deformation at a macroscopic level. To examine this hypothesis, we slice 20-50-μm-thick specimens from aortic tissue, and stretch them under a transmitted light microscope to observe deformation of their inner structure caused by macroscopic deformation. We need to freeze specimens to obtain such thin slices, which normally kill SMCs in the tissue. To keep the cells alive during freezing procedure, we found an optimal freezing condition with the use of a cryoprotectant, dimethylsulfoxide. Additionally, we observed deformations of cell nuclei during stretch of an aortic specimen to find that cell nuclei were not only stretched, but also rotated. Each of SMCs in the wall might deform in a complex manner in response to uniform deformation given at a macroscopic level.
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Takeo MATSUMOTO, Satoshi HIRATA, Kenji TAKEZAWA, Hiroshi MASUDA, Kazua ...
Article type: Article
Session ID: 755
Published: August 02, 2008
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A novel method to obtain pressure-diameter relationship of human brachial artery noninvasively in a wide pressure range was proposed. An airtight box was installed on the forearm and its inner pressure was changed from -100 to +150 mmHg to change transmural pressure of the artery. Inflation and deflation of the artery due to transmural pressure change was monitored with an ultrasound probe attached in the box. When the artery was collapsed by pressurizing the box and then returned to the initial state, its diameter in the physiological state increased, while it decreased following temporal overload to the artery, i.e., temporal negative pressure application in the box. These changes may be caused by the active response of the smooth muscle cells in the media, i.e., Bayliss effect, and are not observed in excised arteries. In vivo measurement of mechanical properties of the arteries is important.
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Masafumi Yoshimoto, Katsuko Furukawa, Takashi Ushida
Article type: Article
Session ID: 756
Published: August 02, 2008
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Compliance mismatch between a native vessel and a artificial vascular graft causes low patency after several years of implantation. To develop a vascular scaffold having a mechanical characteristics like native vessels, a bi-layered tubular scaffold composed of a porous CLLA inner layer and PLLA fibrous outer layer using electrospinning technique was fabricated. A porous CLLA scaffold was inserted into mandrel-type collector having larger diameters than that of CLLA tubular scaffold. In addition, PLLA nanofibers were electrospun onto a pre-strained porous CLLA scaffold. In this study we researched relationships between wall thickness and each electrospinning conditions and effects of pre-straining on mechanical characteristics of fabricated multi-layered tubular scaffold.
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Yuelin ZHANG, Shigeru AOMURA, Satoshi FUJIWARA
Article type: Article
Session ID: 802
Published: August 02, 2008
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The mechanism of coup contusion and contrecoup contusion was studied by impact experiment and finite element analysis. The finite element analysis of the cerebral contusion was carried out by taking skull fracture into consideration to show the relationship of the force duration, pressure fluctuation inside the human head model and the coup contusion, contrecoup contusion. The threshold of the skull fracture was evaluated by using Japan Head Tolerance Curve as -10MPa. The result showed coup contusion would occur when impacted by light weight impactor with high velocity which yields short force duration, and contrecoup contusion would occur when impacted by heavy weight impactor with low velocity which yields long force duration. The result showed on 5 second or less of the force duration, coup contusion occurs dominantly, and contrecoup contusion occurs dominantly over 5 second.
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Yasuhiro MOCHIZUKI, HIROMICHI Annoh, Tetsuya NISIMOTO
Article type: Article
Session ID: 803
Published: August 02, 2008
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In order to define mechanism of nerve damage which ascribable dynamics stimulation, brain tissue under the dynamics stimulation is visualized by immunofluorescence staining and observing brain damage with the use of confocal laser microscope(CLSM). In this study, we conducted following compression experiments and impact experiments by using pig brain from slaughterhouse. Cell body, nerve fiber and nuclear were observed by the CLSM. In cerebral nerve under compression strains of 50%, tear of axon and rupture of cell body occurred. Capillary vessel intrudes cell body in compression strain of 40%. Injury occurred in this case. Tear occurred in axon under compression strain of 30% in the CLSM image. Injury occurred in cell body under compression strain of 20%. Tear of axon on brain surfaces occurred in cerebral nerve under impact load. However, injury did not occur in deep part of brain tissue.
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Atsushi ARAI, Tetsuya NISHIMOTO
Article type: Article
Session ID: 804
Published: August 02, 2008
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Human finite element model is a practical tool that predicts traumatic injury. This research measured the viscoelastic properties of white matter and gray matter by shear, impact and relaxation testing in order to improve a human model. As results, the dynamic modulus of porcine brain and liver was found to increase with frequency. In addition, gray matter was found to be stiffer than white matter over the frequency range of 55-90Hz.On the other hand, white matter was found to be stiffer than gray matter in impact and relaxation testing. These results show anisotropic behavior of white matter concerned in complex mechanical properties of brain.
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Daisuke MURAKAMI, Hirofumi ASANO, Pal CHINMOY
Article type: Article
Session ID: 805
Published: August 02, 2008
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Toshikazu TORIGAKI, Seiichi KOBAYASHI, Yukinobu MATSUSHITA
Article type: Article
Session ID: 806
Published: August 02, 2008
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The first half of this paper introduces our approach to develop human body FEM models. Then, it is shown that a human body model is applied to a recently commercialized "pop-up engine hood" pedestrian protection system as a supplemental evaluation. It is also shown that the model used in this evaluation is well verified with the experimental result using cadavers.
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Yutaka NAKAMURA, Hideo SAKAI, Tetsuo MAKI
Article type: Article
Session ID: 807
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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On the occasion of a side collision of the passenger vehicle the far-side occupant is injured by some contacting interior parts in a vehicle. In this study, it is clarified the influence of the center console rigidity to upon impact behavior and occupant injury by crash test used scale model. Moreover, the belt inserted inflatable tube was effective to improve impact behavior, occupant injury and the amount of the movement about the upper body as a safety device for far-side.
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Tadashi SHIBUE, Izumi MURAMATO, Takashi HAYAMI
Article type: Article
Session ID: 808
Published: August 02, 2008
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Transient behaviour of an old woman's body seated on her seat within a train at an accidental collision is estimated based on finite element method. The purpose of this study is to estimate the effects of collision direction on the behaviour of a human body at the accidental collision. A human body model and a vehicle model with two seats are developed to proceed a numerical simulation within a short time.
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Junichi Takano, Shigeru Aomura, Emiko Kikuchi, Osamu Nitta
Article type: Article
Session ID: 809
Published: August 02, 2008
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In this study, a human motion computer model in a wheelchair was developed to evaluate the effectiveness of a headrest for disabled people traveling in a motor vehicle. The human model was composed of four rigid links and four masses. This model was characterized with muscle reflection defined by Hill's equation. A sudden start experiment by using a carriage on which a wheelchair was fixed with a subject was performed to obtain human muscle parameters and to evaluate the model. Volunteer subjects including disabled people participated in the experiment. The motion and muscle activity of a subject with a headrest was simulated by this model. The muscle reflection of disabled people was stronger than that of normal people in the case of not using a headrest. The result of computer simulation showed that a headrest is more important for disabled people than for normal people.
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Masahito HITOSUGI, Yasuki MOTOZAWA, Shogo TOKUDOME
Article type: Article
Session ID: 810
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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To examine the effect of seatbelt using for pregnant women drivers, sled tests were performed. Changes of intra-uterine pressures in anthropometric dummies representing pregnant women were examined. At the low speed of frontal collision, seatbelt reduced the forward movement of the dummy and subsequently decreased peak intra-uterine pressure by 55% to 65%. At rear-end collision with 6.5 G of acceleration, seatbelt also reduced the forward movement of the dummy due to rebound and prevented the second impact between steering-wheel and the abdomen. This traumatomechanical study using pregnant dummy with varying impact dynamics is useful for improving the seatbelt use in pregnant women drivers.
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Takayuki KOIZUMI, Nobutaka TSUJIUCHI, Jin KURUMISAWA
Article type: Article
Session ID: 811
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Wearing a CRS reduces fatal or severe injuries of children in traffic accidents. However, a lot of children are still injured while wearing a CRS; hence further improvement of CRS crash safety is required. In this research, a load limiter model and an airbag model were attached to a CRS model. Then, the optimization of the CRS model was performed for further improvement of crash safety. The objectives of this optimization were to reduce the injury values for the head and the neck of a 3-year-old FE human model in the CRS. Response surface method was used to improve the efficiency of the optimization. The optimal design was selected and compared with the original design. As a result, this optimization reduced injury indexes of the optimal design compared to the original design. We demonstrated the possibility of improving the crash safety of the CRS.
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Jia HU, Yasuhiro SASAKI, Sota YAMAMOTO, Koji MIZUNO, Eiichi TANAKA
Article type: Article
Session ID: 812
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Finite element (FE) model simulations of frontal sled tests using a 3-year-old Hybrid III dummy FE model and child human FE model seated in a 5-point harness ISOFIX CRS were conducted. A countermeasure of setting a force limiter in the top tether was proposed, which showed an effectiveness on reducing head and chest acceleration and the upper neck loads, just the head excursion increasing but still below the Injury Assessment Reference Value (IARV).
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Masatomo Yamaguchi, Yasuhiro Sasaki, Jia Hu, Sota Yamamoto, Koji Mizun ...
Article type: Article
Session ID: 813
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Finite element (FE) model simulations of side impact sled test using 3-year-old Hybrid III dummy FE model and child human FE model were conducted. The head, chest and pelvis peak accelerations of the FE simulations agreed with the experimental results. The chest deflection was close to the injury assessment value.
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Sota YAMAMOTO, Shinji NODA, Kazuya NARITA, Eiichi TANAKA, Koji Mizuno, ...
Article type: Article
Session ID: 816
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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The purpose of this project is to construct a preventive diagnosis system for hip fracture which is frequently observed among Japanese elderly female. Hip fracture is one of the most important medical problems in Japanese geriatric medicine because it makes a patient difficult to stand and walk. In this study, we evaluated the effects of gait velocity on risk of hip fracture taking into account gait motions of elderly female. Simulation results showed that the risk of trochanteric fracture at pelvis grounding increases with gait velocity while the risk of intracapsular fracture at knee grounding is independent of gait velocity.
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Kenji KOYAMA
Article type: Article
Session ID: 817
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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In recent years, hip protectors have been developed to reduce the shock to the neck of the femur during falls, and these have been evaluated in terms of ease of wearing and impact reduction. In the present study, we developed a dummy model and fall simulation device. We then used these two items to investigate the shock-reducing effect of hip protectors.
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Yasuhiro MATSUI, Shunsuke TAKAGI, Naruyuki HOSOKAWA
Article type: Article
Session ID: 818
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Sho HOSHINO, Tohru NISHIWAKI, Hideo SAKAI, Tetsuo MAKI
Article type: Article
Session ID: 819
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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The rider's behavior and injury at the motorcycle collision influence greatly motorcyde body form, such as existence of a side cowl. Our goal is to clarify the influence of the constraint condition for rider's lower legs on injury level at the side collision of a motorcycle with airbag. As a result, head injury decreased depending on constraining rider's lower legs by side cowl. Moreover, head injury decreased by the device held the thighs downward without any injury.
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Masami IWAMOTO, Akihiro HIROTA, Eiichi TANAKA
Article type: Article
Session ID: 820
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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A constitutive model of cortical bone for representing stiffness and strength anisotropy and asymmetry of tension and compression was applied to a human femur FE model. The femur model was used for prediction of bone fracture patterns under various loadings of tension, compression, torsion, bending, bending/compression, and bending/torsion. Simulation results predicted by using the constitutive model were compared with those predicted by a simplified model with an isotropic elasto-plastic material model. Comparison between the constitutive model and the simplified model demonstrate that the constitutive model well reproduced bone fracture patterns in comparison with the simplified model.
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Fumio MIZUNO, Takashi HAGA, Keita SAWAGUCHI, Tomoaki HAYASAKA, Takami ...
Article type: Article
Session ID: 835
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Chameleons locate the prey with large and independent saccades of the highly mobile eyes. Human cannot control both eyes independently, and cannot perceive independent view fields for both eyes. But we assumed that the human becomes able to perceive the images for both eyes and control visual axes with the appropriate device. In this paper, we describe a comprehensive system which provides two independent view fields to both eyes of human, using two CCD cameras independently controlled and a head-mounted display. Each camera was set to track the movement of the finger so that view fields can take any arbitrary direction. Most of subjects became able to control and understand two different view fields independently after some practice.
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Noriaki TAKAHASHI, Yutaro TAKAHASHI, Takuji KOIKE, Sayuri MURAKAMI, Ky ...
Article type: Article
Session ID: 836
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Development of devices enabling communication under the noise environment such as disaster sites is an important matter. In this study, a communication device was developed using a PVDF film. Its ability in voice acquisition was tested in high noise environments. The results suggest that the PVDF film sensor was able to shut out the environmental noise and was able to acquire the voice signal up to approximately 4 kHz. Moreover, the voice data measured with the PVDF film sensor was clearer than those with the conventional microphone.
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Koichi KURITA, Takuya HISAOKA, Ayumu FUJITA, Yusuke MATSUSAWA
Article type: Article
Session ID: 837
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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We have developed a rehabilitation aid system by employing a non-contact human walking sensing technique and an audito biofeedback technique in order to visualization of progress in walk rehabilitation. This system enables the stable and perfectly non-contact measurement of human walking, which was impossible using the conventional methods. A study has been carried out on a normal subject by fastening a left leg onto a splint with bandages. As a result, it is possible that a rehabilitant and a physical therapist know objectively the pace of progress in walk rehabilitation using this rehabilitation aid system.
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Sozo Ueno, Yohsuke IMAI, Tomoaki Hayasaka, Takuji ISHIKAWA, Takami YAM ...
Article type: Article
Session ID: 838
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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A number of elderly people have a difficulty in going to the toilet by themselves. They sometimes wear an adult diaper but it makes the elderly uncomfortable and unsanitary. Moreover, their pride is injured by wearing the diaper. A portable toilet is also used for the elderly requiring assistance to the toilet. The portable toilet is not a sufficient solution because it is also uncomfortable and unsanitary for them. We propose a mobile toilet system for solving this problem. The concept of the proposed system is as follows. The toilet waits for calling signal from the elderly at standby room. When the calling signal is received, the toilet autonomously goes to the bedroom and approaches the elderly. After excreting, the toilet returns to the standby room and automatically disposes feces. This system is also equipped with analyzing function of feces for monitoring their health condition. We have developed a prototype of the toilet.
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Kozo Nakagawa, Tsutomu Tajikawa, Atsushi Sakurai, Kenkichi Ohba, Yasuo ...
Article type: Article
Session ID: 840
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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To study the airflow characteristics in human nasal cavities with complex geometries assists in understanding mechanism of nasal stuffiness in breathing. Medical treatment of nasal stuffiness can include ablative surgery using an endoscope, but treatment success depends on the experience of the surgeon, because no objective index has been established to specify the affected areas. This study investigated flow property in simplified nasal cavity models which were matched hydraulic diameter with human nasal cavity. As a result, the fluctuation of the pressure drop between nostril and pharynx in the case of a simplified patient model was in good agreement with the rhinomanometry measurement in the case of a patient. Flow visualization results showed that vortex flow occurred in the nasal vestibule during inspiration.
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Masashi SHIOTANI, Daido FUJITA, Kenkichi OHBA
Article type: Article
Session ID: 841
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Myocardial infarction and brain infarction are caused by a vessel lesion like arteriosclerosis. It is known that vessel lesion occurs commonly at curve or bifurcation area of aortic arch and coronary artery. Stenosis by vessel lesion influences flow field of blood in arteries. This study investigated the interactions between blood flow and vessel wall of a coronary artery that has became stenosed by vessel lesion. We made elastic realistic models with stenosed at bifurcation proximity and conduct in vitro experiment. As a result, pressure drop of 0.4 kPa occurred at a stenosis in 50% stenosed model, pressure drop of 3 kPa occurred in 70% stenosed model. Moreover, in 70% stenosed model, ellipse cross-sectional collapse occurred at downstream position of a stenosis.
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Minoru MORITA, Zhongwei JIANG, Naoki CHIJIMATU, [in Japanese], Shoichi ...
Article type: Article
Session ID: 842
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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The cerebral thrombus or blood clot might cause cerebral stroke and even decease if the clot could not be dissolved within several hours after it was formed. We presented a treatment method of utilizing micro stirrer attached on the catheter tip. This paper presents the fundamental study on design of a micro stirrer for high effective dissolution. Based on the experimental results, the micro stirrer is analyzed by FEM. Using the FEM, new type of stirrer are evaluated. The obtained results of the in-vitro experiment and FEM analysis that the dissolution performance is influenced by the power into the fluid. Moreover, increase of the stirring area was tried by adjusting the input signal, and this effect was confirmed by the FEM analysis.
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Ippei Norimura, Kazuyuki Minami, Katsuya Sato
Article type: Article
Session ID: 843
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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It is a problem that metal stent can't be used to treat young people medically because it stays permanently in body. And it also cause artifact in MRI imaging. So we have developed polymer stent with hoop structure that can be produced with polymer film. In this research, we evaluated radial force of stent as mechanical characteristics. We fabricated and examined stents made of polyethylene terephthalate (PET) and biodegradable polymer, poly L-Lactide (PLA). The experimental results show that PET and PLA stents have larger radial force than that of a type of metal stent.
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Kenichi OSHITA, Eiji ISOBE, Shigeru NAGAKI
Article type: Article
Session ID: 844
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Pressure ulcer is intractable ulcer and have much emotional distress for patients and increase strain for care person. Now an pressure ulcer is concern in our country with increase bedridden elderly with expeditious advent of aging society. Therefore in this research we focused attention on the external causes of pressure ulcer generating mechanism. We carried out several experimental investigations and finite element analysis for the realization of easing the burden of patients. There was little influence that sex exerts on the stress on the skin surface under the sacrum. Furthermore, it was shown that the state of the stress in the body greatly depended on the projection shape and the size of the sacrum.
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Taku KOMURA, Motomu NAKASHIMA
Article type: Article
Session ID: 845
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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The objectives of this study were to develop a musculoskeletal model which can compute muscle load of the whole body for a pregnant woman, and to clarify the muscle load by the simulation. First, non-pregnant woman model was constructed based on the body size of the average values for the Japanese women. Then, a pregnant woman model was constructed paying attention to the features of the pregnant women, such as the exaggerated abdomen, load on the abdomen, increased weight and body fat. A simulation of the standing position was conducted for these models. The hip flexion angle was varied as a parameter. It was found that the muscle force of erector spinae for the pregnant woman becomes three times larger than that for the non-pregnant woman.
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Tsutomu EZUMI, Heizo KAJIWARA
Article type: Article
Session ID: 846
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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In this research, picked up to the Joint of the Foot. Recently, the number of foot joint syndromes by an acquired transformation increases. Especially, a flatfoot has a lot of patients as an acquired case. The bone in the arch of a normal foot and a flat foot was reproduced by three-dimensional model, the stress distribution was analyzed by the photoelastic investigation, and it made comparative study of them. The experiment analysis result showed the following things. It is calcaneus that change was looked at by especially stress distribution, and the stress value became high in the flat state outside in the normal condition at inside sidewall. If this will be in a flat state, it will be considered to be because for calcaneus to rotate inside.
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Nobutaka MAEZAKI, Tsutomu EZUMI, Masashi HACHIYA
Article type: Article
Session ID: 847
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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Takeshi SHIMOTO, Yoshitaka SHIRAISHI, Tatsumi FUKUSHIMA, Daikei ARATSU ...
Article type: Article
Session ID: 848
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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This study investigated the mechanisms of anterior impingements of the post with the femoral intercondylar notch. Five posterior stabilized prosthesis designs were tested to study using an artificial knee joint simulator. The contact pressure and contact area were measured at five hyperextension angle (5 degrees, 0 degrees, -5 degrees, -10 degrees and -15 degrees) and two axial tibial rotations (0 degrees and 5 degrees) under the applied loads of 100N. Edge loading was found at the anterior corner of the post in the post with flat surface. Understanding the advantage and disadvantage of the polyethylene insert post function may help to develop sophisticated component design.
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Tatsumi FUKUSHIMA, Hidehiko HIGAKI, Yoshitaka SHIRAISHI, Takeshi SHIMO ...
Article type: Article
Session ID: 849
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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This study was aimed to determine in vivo kneeling kinematics after total knee arthroplasty (TKA). Image matching technique with high-resolutional flat panel detector (FPD) was used for the motion analysis of kneeling and walking. We focused on relative location between the femoral component and polyethylene insert. The result indicated that motion analysis of artificial knee implants could clarify typical motion patterns depending on patient. Our analysis could reproduce in vivo relation of contact between a femoral component and polyethylene insert on a computer, which gave us important information that could not be obtained by conventional X-ray image.
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Yoshitaka SHIRAISHI, Tatsumi FUKUSHIMA, Hidehiko HIGAKI, Takeshi SHIMO ...
Article type: Article
Session ID: 850
Published: August 02, 2008
Released on J-STAGE: August 01, 2017
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This study aimed to develop a three-dimensional motion analysis for a natural knee joint, with high precision in vivo using an image matching technique with high-resolution X-ray image from flat panel detector (FPD). The image matching was performed determining the strength of a correlation between X-ray images and computer simulating images. However, the number of pixels in a whole reconstructed image was so huge. Therefore, in this study, several windows were set up, in which a region of interest was determined to calculate instead of viewing the whole region of the image. Computer simulating image was created by the three-dimensional solid model. Three-dimensional solid models were reconstructed using computed tomography (CT) data. We report the results of a motion pattern in analysis for a natural knee joint during deep flexion using the method.
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