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Tatsuki TAKASHIMA, Yoshitaka NAKANISHI, Hidehiko HIGAKI
Article type: Article
Session ID: 445
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The 3D scenography (stereoscopic vision) has various applications, in which binocular disparity display is generally used in order to project pictures onto the each eye. The binocular display, however, imposes discrepancy between accommodation distance and vergence distance on special perception, so that the user suffers from physical and visual strain. We proposed dual-convertible lens system as an accommodative compensation system. Two serial convertible lenses are installed between the user and the display, can cut down the visual discrepancy and the user make binocular vision easy. We researched effectiveness of dual-convertible lens system for stereoscopic vision. We measured the break point and the recovery point. Images for right and left eyes were produced on the personal computer. The distance between two images was changed for changing the vergence distance. We proved that the user could fuse together a right image and a left image in the difficult condition.
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Yasutomo UETSUJI, Kouhei IMOTO, Sadaomi KUMAZAWA, Kazuyoshi TSUCHIYA, ...
Article type: Article
Session ID: 446
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Yuji OKUDA, Kouhei IMOTO, Kazuyoshi TSUCHIYA, Yasutomo UETSUJI, Hideto ...
Article type: Article
Session ID: 447
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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We focus on the development of the new biocpmpatibility piezoelectric material as a microactuator for Bio MEM. The combinations of biocompatible atoms to constitute perovskite-type crystal structure were selected by those atoms that satisfy geometric stable condition. In the case of perovskite-type crystal structure, we have chosen MgSiO_3 as a candidate for piezoelectric materials. The stable cubic structure of MgSiO_3 was obtained by first principles DFT Helicon wave plasma sputtering method can produce sputtered particles, which have larger potential energy, because of low working pressure. However, in order to create new biocompatibility piezoelectric material by the method, there are many sputtering factors. Therefore, the experimental design method was used for invention condition search. It was shown that composition gap for deposited thin film was influenced by substrate temperature and target ratio.
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Kouji NISHIZAWA, Kousuke KISHI, Fujio TAJIMA, Ken-ichi SUDOU, Masakats ...
Article type: Article
Session ID: 448
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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A new structure of joints in surgical tools is proposed in this paper. Using this new structure, it becomes possible to operate a surgical tool with multiple degrees of freedom and smooth motion. In this new structure, a middle plate connects two parts that have rolling contact between each other. Furthermore, some drive wires are wired so that they cross between the two parts. There are two main features in this new structure. First, the path length of the wires is independent of the joint angle. Secondly, the joint and grippers are controlled independently. Using the independence of the grippers from the joint the operation of the surgical tool becomes easier for the operator. This is because it becomes possible to control the joint and grippers like the wrist and hand of a human being.
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Yasuhito NIWA, Naohide TOMITA, Shuichi YAMADA, Qing-Qing Ni, Nobuyuki ...
Article type: Article
Session ID: 449
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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So-called "delamination destruction" is often observed on ultra-high molecular polyethylene (UHMWPE) knee components. We reported that the grain boundary becomes the place at which destruction takes place and presence of D,L-α-Tocopherol (vitamin E:VE) at the grain boundary prevents crack propagation. It was also reported that partial hardening (or degradation) might be prevented by the anti-oxidization effect of VE. The purpose of this study is to clarify the mechanism in which VE suppresses the influence of gamma-ray irradiation, and the mechanism of delamination destruction using the image correlation method with tensile-testing. The results showed that the increase-rate of volume strain in the grain boundary was lower than at in grain for the gamma-irradiated UHMWPE. In contrast, the virgin sample and the VE added sample show contrary results.
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Satoshi TERAMURA, Naohide TOMITA, Shunichiro KAWASHIMA, Masahiko AOKI, ...
Article type: Article
Session ID: 450
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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We have investigated the crystallinity by micro-Raman spectroscopy. Raman spectra for C-C stretching mode showed a mount come from amorphous at the side of the peak from crystalline regions. The results showed that only the specimen strained at 20% had higher crystallinity especially at grain boundaries. These results suggest that γ-irradiation makes molecule chain short and then crystallization is caused by tensile deformation. It is also suggested that that the addition of D,L-α-tocopherol would inhibit oxidative degradation and crystallization when tensile deformation occurs on γ-ray irradiated UHMWPE.
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Yoshitaka NAKANISHI, Tatsuki TAKASHIMA, Hidehiko HIGAKI, Takatoshi UME ...
Article type: Article
Session ID: 451
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Wear characteristics have been investigated in polyvinyl formal (PVF) as an artificial articular cartilage for joint prostheses. This bearing of the joint has been designed and constructed to produce larger initial contact areas and thicker theoretical film thickness than the conventional UHMWPE bearing. The main advantage of using the bearing may be associated with micro-elastohydrodynamic lubrication, and the low elastic modulus layer may also produce local deformations, which enhance squeeze film action. Wear tests were performed with a knee joint simulator. The PVF was adopted as the articular cartilage for the flat tibial component. The compliant bearing had a spherical surface that was made of stainless steel. The results showed that no detectable wear debris was generated in the simulation tests conducted over 1.0 million cycles. Although there still remain some problems to solve, the PVF seems to be a very interesting and promising material, which meets the requirements of artificial articular cartilage.
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Kazunari HAMADA, Yuji Tanabe, Tatsuya KIKUCHI, Koichi KOBAYASHI, Makot ...
Article type: Article
Session ID: 452
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Articular cartilage is biphasic material consisting of solid and liquid, and there is difference in permeability between normal articular cartilage and OA articular cartilage. We can measure water content in specimen nondestructively using NIR spectroscopy. Then we applied NIR spectroscopy to nondestructive testing for physical property of articular cartilages. We deal with the two aspects of the detailed relations between recovery of absorbance and degeneration of human cartilage, that is, 1) relation between the degeneration of human articular cartilage and pattern of absorbance with respect to time after removal of indentation load, 2) relation between the degeneration of human articular cartilage graded by Mankin Score and variation of absorbance with time after removal indentation load. In the most of specimens graded as "normal", the absorbance initial decrease and the subsequent increase. In the specimens of "normal", the Mankin Score was able to be related to the time when absorbance had the minimum value. It is concluded that near infrared spectroscopy enables us to capture the increase of permeability with an increase of damage in articular cartilage.
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Yutaka KAWASAKI, Koji MORI, Hiroki SADAMARU, Takashi SAITO
Article type: Article
Session ID: 453
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Morphological diagnoses such as MRI are often used for assessment of articular cartilage. The method that the quantitative evaluation of articular cartilage (hardness, thickness, and roughness of the surface) using ultrasonic echo was proposed. However, the relation between ultrasonic echo and matrices in articular cartilage such as collagen is little known. The objective of the present study is to investigate the relation between ultrasonic echo and collagen in articular cartilage using Fourier transform Infrared Spectroscopy. The result of the study showed that the signal intensity from ultrasonic echo depends on the quantity of collagen. Moreover, it confirmed that the signal intensity of articular cartilage reflected the collagen content in the articular cartilage within 150m of depth from the surface of the articular cartilage.
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Koji MORI, Yasuaki NAKAGAWA, Hiroshi KUROKI, Keisuke NAKASHIMA, Takash ...
Article type: Article
Session ID: 454
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Quantitative estimation method and device of articular cartilage have been needed to evaluate various new treatment methods for joint disease. We proposed the non-contact ultrasonic evaluation method and investigated the accuracy using animal study and in vitro study. The advantage of the ultrasonic method is sensitive to the change of articular cartilage in the early stage of joint disease. The mechanism of the sensitivity, however, was not cleared. The objection of this paper was that the mechanism was investigated using numerical analysis. The relation between the distribution of solid phase and signal intensity of ultrasonic echo was simulated. The result showed that the signal intensity was in proportion to the quantity of solid phase near the cartilage surface. The simulation suggests that the ultrasonic method estimates the degree of overall cartilage damage or repair from the information near cartilage surface.
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Yoshiaki SUGAYA, Naoya SAKAMOTO, Toshiro OHASHI, Masaaki SATO
Article type: Article
Session ID: 501
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Effect of hydrostatic pressure on morphology and expression of VE-cadherin of cultured bovine endothelial cells (ECs) was investigated. After confluent ECs were exposed to hydrostatic pressure of 0, 50, 100 and 150 mmHg for 24 hours, F-actin filaments and VE-cadherin of ECs were stained. Statically cultured ECs formed a cobblestone pattern of contact-inhibited cells with thin, short F-actin filaments. VE-cadherin was uniformly distributed at the periphery of cells. In contrast, ECs exposed to hydrostatic pressure exhibited marked elongation and random orientation, together with development of centrally located, thick stress fibers. Pressured ECs also exhibited multilayered structure unlike monolayer of control conditions. VE-cadherin was sparsely distributed around the periphery of cells, and its expression was lower than that of control. These results suggested that hydrostatic pressure inhibited the expression of VE-cadherin, resulting in loss of contact inhibition followed by formation of multilayered structure.
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Kazuaki NAGAYAMA, Shinichiro YANAGIHARA, Takahiro SHIRONO, Takeo MATSU ...
Article type: Article
Session ID: 502
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Contractile properties and actin filament morphology were measured in smooth muscle cells freshly isolated from rat thoracic aortas. The major length of the cells before and after contraction induced with 10^<-5>M serotonin was 49.0 ± 5.6 μm (n=7, mean ± SEM) and 39.2 ± 5.4 μm, respectively, and the cell shortening was 20.1 ± 3.9 %. The cell shortening increased with their initial cell length, peaked at 〜50 μm, and then decreased. The actin filaments in the untreated cells were mostly straight fibers running along the major axis of the cells, while those in the contracted cells. had aggregated structure without preferential direction. The volume and the average fluorescent intensity of the actin filaments estimated from their confocal images were not significantly different between the untreated and the contracted cells. These results may indicate that the cell contraction is accompanied not only by the sliding of actin and myosin filaments but also by the entanglement of the actin filaments, maintaining the amount of actin filaments.
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Nobuyuki SHIBATA, Naohide TOMITA
Article type: Article
Session ID: 503
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Cartilage tissue has limited capabilities of regeneration. This thus makes it a candidate for tissue-engineered solutions. However the mechanical environment of chondrocytes embedded in an engineering scaffold has not been elucidated. Multi-scale finite element simulation based on the biphasic theory was performed to investigate the mechanical environment of chondrocytes in a tissue-engineered cartilage construct.
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Sho ISHIYAMA, Yoshinori SAWAE, Sachiko IDA, Kazuhiro NAKASHIMA, Teruo ...
Article type: Article
Session ID: 504
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In this study, the influence of hydrostatic pressure loading on mechanical properties of chondrocytes-agarose specimens was investigated. After 1 day, 8 days and 22 days in unstrained culture, the specimens were exposed to hydrostatic pressure (1MPa, 1Hz, 6h/day) for 7 days. Then, tangent and equilibrium moduli of the specimens were obtained by unconfined compression test. The results showed that the hydrostatic pressure loading at the early stage of culture improved tangent moduli of specimens, but if the extracellular matrix was formed around the cells in advance, the effect of hydrostatic pressure loading did not appear.
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Atsuhiro OURA, Makoto KAWANISHI, Katsuko FURUKAWA, Takashi USHIDA, Tet ...
Article type: Article
Session ID: 505
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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One of our goals in the field of tissue engineering is to develop the remodeled artificial cartilage for the treatment of cartilage defects. Many studies described that intermittent hydrostatic pressure stimulation is efficient in culturing for chondrocytes, because the internmittent HSP could keep the specific ability of chondrocytes to synthesize aggrecan and type2collagen. In this work we constructed the culturing system with intermittent hydrostatic pressure, which can control the gas pressure of pCO_2, pO_2 and frequency of HSP around chondrocytes. In addition we studied the effects of hydrostatic pressure on gene expression of the chondrocytes. Primary cultures of bovine chondrocytes were exposed to hydrostatic pressure applied intermittently 0.5Hz, 3.5MPa for 4 or 24 hours a day in medium containing 10% fetal bovine serum and cultured for 4 days. As the result, we found that the hydrostatic pressure reduced the expression of type1collagen-mRNA, also enhanced that of type2collagen and kept that of aggrecan-mRNA. Therefore, this newly constructed pressure system must be an efficient tool to investigate the appropriate hydrostatic pressure pattern for remodeling of artificial cartilage in the future.
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Kazuhiro NAKASHIMA, Teruo MURAKAMI, Yoshinori SAWAE
Article type: Article
Session ID: 506
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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PVA hydrogel is a kind of prospective material as artificial cartilage. It is necessary to investigate the wear properties of PVA hydrogel in severe condition. Lubricant containing protein was used in reciprocating test. Proteins formed the boundary film on PVA hydrogel, and the wear was reduced. Hyaluronate solution as lubricant contained albumin and γ-globulin which was labeled fluorescently as typical protein in synovial fluid. The remaining film was observed under amicroscopy fluorescently. Proteins formed adsorbed film on glass plate and two type of layer was observed. First layer is rich in albumin and second layer is rich in γ-globulin. There is difference between albumin and γ-globulin on adsorption strength. It is considered that albumin layer takes charge of shear, and γ-globulin layer protects material from wear. Therefore existence of layer containing albumin or γ-globulin is effective to reduce wear.
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Tsutomu SATO, Kazuhiro NAKASHIMA, Yoshinori SAWAE, Teruo MURAKAMI
Article type: Article
Session ID: 507
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The influence of the surface film containing the synovia ingredients on friction was investigated for a sliding pair of PVA hydrogel and glass plate with and without LB film in reciprocating apparatus. It turns out that a hydrophobic film raises friction in the experiment using the monolayer of DPPC produced by the LB method. From this result, it is thought that a hydrophobic film has prevented the lubricant from entraining. The hyaluronate solution containing both albumin and γ globulin showed lower friction.
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Daisuke KATAKAI, Hiromichi FUJIE, Kiyoto NAGAI, Norimasa NAKAMURA, Nor ...
Article type: Article
Session ID: 508
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The patellofemoral joint surface of the femur of New Zealand white rabbit was drilled to create a cylindrically shaped full-thickness defect (4(ψ)×7(l)). A hydroxyapatite-based scaffold for born regeneration (Neobone) was implanted into the defect with bone morphogenetic protein (BMP). Eight and thirteen, months after the implantation, the cylindrically shaped cartilage/bone plug was extracted from the joint surface, and was subjected to static and dynamic compression tests and a friction test. Results revealed that, 13 months after the implantation, the tangent modulus of the regenerated cartilage almost recovered -to control level in static compression test although the deformation rate remained much higher than control level in dynamic compression test. The friction coefficient of the regenerated cartilage recovered to control level 8 months after the implantation. These results suggest that the mechanical properties of the cartilage regenerated by Neobone with BMP for 1 year recover well except for dynamic compression property.
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Masaru Higa, Ikuya Nishimura, Fuyuhiko Maeda, Takahiro Seno, Yasuharu ...
Article type: Article
Session ID: 509
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Canine total hip replacement (THA) is one of the treatments of canine osteoarthritis (OA). The bone screws are used to fix acetabular cup on THA. Two screws are mainly used. However, compared to human THA, these screws were not considered enough about direction, size, and so on. The porpose of this study is to consider the possibility of three screws fixing. Finite element method was used for comparing two screws fixing and three screws. Rightly, three screws have higher fixing strength. However, these also have higher risk of bone fracture. From results, three screws and two screws are not significantly different on acetabular bone stress. Therefore, the possibility of three screws fixing was suggested.
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Ikuya NISHIMURA, Ryota SHIMIZU, Toshiki NAKAMURA, Takeo MATSUNO, Yoshi ...
Article type: Article
Session ID: 510
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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A high prevalence of thigh pain has been reported after cementless total hip arthroplasty (cementless THA). But it is still unknown about the in-depth mechanism. Therefore in order to investigate the relevance between the occurrence of thigh pain and the stress in femur after cementless THA, the experiments on animals were carried put. The animalexperiments revealed that reaming volume of the medullary cavity have an effect on the occurrence of thigh pain.
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Keiji IMADO, Hioomi MIYAGAWA
Article type: Article
Session ID: 511
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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A Simplified calculation for contact temperature proposed by Kennedy was applied to a spherical bearing. The solutions obtained were compared with the experimental study. In the case of a femoral head of CoCrMo against UHMWPE cup, the contact temperature rise of 10.4 ℃ was obtained, which agreed well with the experimental value. On the other hand, in the case of an alumina (Al_2O_3) head against UHMWPE cup, the temperature rise was 5.8 ℃, which was relatively smaller value in compared with the experimental results. As the results of this research, it was concluded that the Kennedy's method was profitable in contact temperature calculation.
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Keiichi KATAMURA, Michiaki KOBAYASHI, Hiroyuki FUJIKI, Junichi SHIBANO
Article type: Article
Session ID: 512
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The artificial knee joint has been applied in clinical use for more then thirty years, while there are still many problems which must be solved. In this study, stabilizer installation position of artificial knee joint was analyzed using non-linear optimization method with motion analysis data. As a aresult, the installation position to improve the contact conditions of the stabilizer type artificial knee joint was clarified.
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Nobuo Sakai, Akira Ono, Yoshinori Sawae, Teruo Murakami
Article type: Article
Session ID: 513
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Artificial joint is generally applied for surgical operation on the patients of osteoarthritis, rheumatoid arthritis etc. Current major artificial knee joint is composed of metallic or ceramic femoral component and tibial component of Ultra high molecular polyethylene (UHMWPE), and this constitution is durable for more than 10 years in clinical use. However, it is indicated that wear debris of UHMWPE activates phagocyte or macrophage excessively, and finally the problem of loosening occurs. One of the solutions to reduce wear debris is to apply fluid film lubrication mode constructively. We observed the degree of the fluid film formation of artificial knee joint utilizing electric resistance method. In experimental processes, artificial knee joint was installed in the knee joint simulator, which could generate practical condition of walking in 4-degrees of freedom. The experimental result showed that high degree of separation by fluid lubrication occurred in the condition of tibial component of UHMWPE flat plate. Furthermore, the application of compliant material as rubbing surface improved fluid film formation in simulator test.
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Kazuki NITTA, Masatomo FUJIKI, Shun OGATA, Yuya KURAOKA, Satoshoi UOKA ...
Article type: Article
Session ID: 514
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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We have developed the programmable, Continuous Passive Motion device (0PM) to achieve the treatment with effective load reduction by following to the position of the knee rotation center axis and load sensor feedback to the motion. In order to decrease the load to the tibia, the posture of the tibia is modified according to the output of the strain gage mounted on the link by the tibia. The effect of the load sensor feedback to the motion was verified by the experiments with the CPM device.
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Roko MIKAMI, Masafumi MORITA, Kiyoshi MABUCHI
Article type: Article
Session ID: 515
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Blood-sampling is routine work in clinics. If blood-sampling is skillfully automated, not only pain of patients but also labor or risk of technicians must be reduced. Detecting and imaging of blood vessels is an essential technique to realize automatic blood-sampling. The purpose of this study is to detect the suitable spot in the blood vessel using near-infrared irradiation. A beam of near-infrared ray was irradiated from the skin. The reflection light was detected by a phototransistor. Blood vessels were distinguished by the uneven distribution of the absorption ratio of the light. The strength of the reflection, which was detected by the phototransistor, was digitized by an A-D converter. Mapping of the data was performed in the personal computer. To shorten the scanning period, 20 pairs of the LEDs and the phototransistors were assembled in a probe.
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Yutaka FUKUI, Tsuneo KAWANO
Article type: Article
Session ID: 516
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The purpose of this study is to measure torsion angle of the human forearm during working and to construct a model for representing the torsion and the difference of the range due to the locations of the arm. The torsion angles of the forearm were measured using Shape Tapes when the subject turned a knob with gripping as much as possible. The difference of the torsion range was examined among the thirty-four knobs, which were placed at the mutually different locations around the subject. It was found that the torsion angle varied with the locations and the point existed where the torsion angle became largest between the wrist and the elbow. Finally a forearm model composed of the ulna and the radius was constructed to represent the torsion and the restriction due to the locations of the arm.
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Kousuke MOTAI, Sho NAKAJIMA, Hiromichi FUJIE, Toshinori KIKUCHI
Article type: Article
Session ID: 517
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The frictional characteristics of earthworms were determined using a 3D micro force plate developed in our laboratory. It was possible to measure the frictional force and vertical force applied to the force plate. Earthworms, named "Eisenia fetida" and "Pheretima hupeiensis" in Japanese, were used to determine their frictional behaviors when they moved on waterproof sand papers fixed to the force plate. The coefficient of static friction of Eisenia fetida against the sand papers were 6.9, 5.7, and 3.9, at the roughness of 2.98, 3.73, and 16.2 μm, respectively, with a significant difference (p<0.05) observed between the roughness of 2.98 and 16.2 μm. The coefficient of friction of Pheretima hupeiensis against the sand papers indicated a smilar trend as to Eisenia fetida, with a significant difference observed between the roughness of 2.98 and 16.2 μm. Note that the coefficient was significantly higher in Pheretima hupeiensis than in Eisenia fetida at the roughness of 2.98 μm. Mucous liquid secreted from earthworms was observed on the surface of the roughness of 2.98 and 3.73 μm after the friction test. Microscopic observation indicated that earthworms had many spikes called "seta" around their bodies and that they controlled the length of the seta during the movement on an irregular surface. These results indicate that earthworms control their frictional behavior in response to various surfaces that they contact by the use of their mucous liquid and seta They also indicate that the mucous liquid plays more important role than the seta in controlling the frictional behavior of earthworms in response to relatively smooth surfaces.
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Akihiro OBO, Shinichiro HOSOI, Shirou ITAI, Yasuhiro KUSHIHASHI, Yoshi ...
Article type: Article
Session ID: 518
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In order to investigate co-creation in communication and morphogenesis in plant, not only spatio pattens of electric field forming around root but also temporal changes must be measured in detail. Therefore, high speed vibration probe system was build by installing newly proposed vibration mechanism in this study. Consequently, applying our system, it was shown that fluctuation exists in the electric field and its spectral distribution often follows a trend of 1/f^k. Furthermore, entrainment behavior was observed in some cases of settling two roots in the same chamber.
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Mika MURAI, Jun-ichi SHIBANO, Shigeru TADANO, Akihisa ATOU, Satoshi AS ...
Article type: Article
Session ID: 519
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Since damages metal cable the spinal some tissue during operation, ultra-high-molecular-weight-polyethylene (UHMWPE) cable is being used now-a-days for spinal fusion. Aging effect its use in vivo has been reported yet. This study also shows the constant breaking-strength and breaking-strain properties of UHMWPE cable. Specimen of cable of 200mm length was implanted under skin of mouse for different periods. The implant periods were for one week, two weeks, one month, three months, six months and twelve months. Tensile test of the specimen were performed at the room temperature using MTS testing machine and the respective breaking-strength and breaking-strain were measured. The breaking-strength and breaking-strain of the specimens were found unchanged, which shows that UHMWPE remained intact in vivo.
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Dai WATANABE, Kohei YUGE, Kohei TOMONAGA, Tetsuya NISHIMOTO, Susumu EJ ...
Article type: Article
Session ID: 520
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In this paper, dynamic FEM analyses on the impact injury mechanism of a human head were performed. The human head model was built up by the VOXEL approach(1), where 40 million parallelepiped elements were created with 433 slice CT images (512×512 pixels). The material of a human head is classified into 10 tissues such as a scalp, CSF, a skull, a brain, dura mater and so on. The original digital model was remodeled with 1.22 million elements in order to finish the analysis in a reasonable computational time by a PC cluster system. To check usability of the present model the dynamic behaviors of a human head subjected to impact loads on the forehead were conducted. The obtained results agree well with the cadaveric tests by Nahum. In the second analysis side impact loads were assumed for the head model. The large equivalent strain was observed in the central region of the brain as well as the region near the impacted point, where hemorrhage is often found in actual damaged human heads by impacts.
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Noriyuki HAYAMIZU, Eiichi TANAKA, Sota YAMAMOTO
Article type: Article
Session ID: 521
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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A mathematical model of muscle has been formulated to be used in the motion analysis for evaluating muscular fatigue and recovery. To take account of the effect of fatigue and recovery, the model of a rate type was formulated based on the ideal of changes of state of motor unit. Four types of state of motor unit were introduced to simulate fatigue and recovery under the dynamic condition. The response of the model was compared with that of the previous model and the experimental data in literatures. The results showed reasonable agreement. The model is capable of simulating fatigue and recovery under the dynamic conditions.
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Noboru MIYATA, Takashi YOKOI, Miyoko YOSHIKAWA, Yasunori GOTO
Article type: Article
Session ID: 522
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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For the estimation of the biomechanical and psychological factors in step ascending and descending, we measured trajectories of body markers, floor reaction force and sensory evaluation. We calculated 3-dimensional (sagittal, frontal and torsional) joint torques of lower extremes in the method of inverse dynamics. From the result of analysis, we show that not only the torsional motion has an important role in step ascending and descending, but also psychological factors is related with the biomechanical factors such as joint torque.
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Hisashi NAITO, Kazunori Hase, Takenobu INOUE, Takanori AIKAWA, Nobuya ...
Article type: Article
Session ID: 523
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper describes a newly developed computer simulator for human walking with hip disarticulation prosthesis based on neuro-musculo-skeletal model of human body and mechanical model of hip prosthesis. This simulator is able to generate three-dimensional walking motions of an entire body wearing a hip prosthesis. It is shown that the simulated characteristics of a walking movement for a lower lumber joint, a normal foot joint and a prosthesis leg are qualitatively similar to the walking patterns when using a real hip prosthesis. This suggests that this simulator may compute the movement of a human body and the behavior of a hip prosthesis, including the interaction between them. Therefore, the developed simulator may contribute to development and design for hip disarticulation prostheses.
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Noritaka NAGAI, Mitsunori Tada, Takashi Maeno
Article type: Article
Pages
157-158
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper describes a method to identify the material properties of biological soft tissue in vivo, considering nonlinearity in the high strain region, and the multilayered structure whithin which the material properties differ. In this method, deformation of the tissue was measured from MRI images, analyzed using the Finite Element Method, and the material properties optimized. To verify the practical effectiveness of this method, we used a 3-layered rubber column, as, an example. The results show, the accuracy of the identified properties were over 20%, however, while the reproducibility of deformation was approximately 1.2%. We believe higher accuracy can be achived by improving, measurement precision of the form and deformation.
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Hitoshi MIYAKE, Hiroaki MATSUNAGA, Tekaaki SATO
Article type: Article
Session ID: 525
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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For elderly slip preventing is urgently need to avoid bone fracture, which might lead bedridden for all his/her life hereafter. We have proposed a new gravity measurement method called the tracking method, which is sensible with the real and/or the virtual reality fatigue. In this study we examined two women with this tracking method to make slip preventing functional model.
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Atsushi TAKASAKA, Shigeru TADANO, Satoshi NISHIDA
Article type: Article
Session ID: 526
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Since lifting is common in daily life and worksite, inappropriate ways of lifting generally cause low back pain. In this paper, the lifting motion with reduced body burden was simulated using three dimensional link model of a whole body. Motion of the model was analyzed using Newton-Euler method. Musculoskeletal model of upper limb was also developed to predict the muscle force by the simulation. Successive Quadratic Programming (SQP) method was used as an optimization tool for the simulation and analysis. The optimized muscle forces were obtained by minimizing the objective function, sum of squares of muscle force.
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Tadasuke KATUHARA, Shunji HIROKAWA, Ayaka OHTUKI
Article type: Article
Session ID: 527
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Curvature analyses on the artificial knee joint surfaces have not been fully performed. In this study, artificial knee joint surfaces were described by the parametric polynomials in order to suppress unnecessary undulation which might be generated during the reconstruction processes when other equations were applied. Then, curvature analyses were performed or three types of artificial knee joints which have been described by the above-mentioned polynomials. Further, congruencies between the femoral condyles and the insertion plate fixed on the tibia were introduced at various knee angles. Finally, the features of the surface shapes were discussed for three types of artificial knee joints.
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Naoki KANNO, Shigeru TADANO, Yukio NAKATSUCHI
Article type: Article
Session ID: 528
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Femur fracture in aged people is a serious problem as it sometimes leads to be bedridden. Every year approximately 90,000 people in Japan are found to be suffered from femoral neck fracture. 75 percentages of the fractures are due to falling. Since bone density reduces with aging, the possibility of fracture in aged people is very high. In this study, stress distributions at different possible impact locations were analyzed using 3-dimensional Finite Element Method. As a result, it was clear that stress distribution around the femoral neck greatly depended on the impact location due to falling. The fracture risk was found to be increased rapidly with aging. Under applying the impact force at posterior direction in great trochanter, femoral neck showed the highest fracture risk.
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Toru Oshima, Kiyoshi Toriumi, Minayori Kumamoto
Article type: Article
Session ID: 529
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The conformance of a manual wheelchair used to be evaluated from the viewpoint of human engineering but can now be evaluated biomechanically. However, the musculoskeletal motions of the upper limbs are very complicated, and evaluating the relationship between muscular strength and driving force is theoretically possible but not easy. Recently, the FEMS Program was developed to analyze the relationship between functionally effective muscular strength (FEMS) and output force. This program simplifies the complicated musculoskeletal system of human limbs into a Two-joint link model with three pairs of functionally effective muscles (FEM). In the present study, the relationship between seating position and driving force was clarified from the output force distribution of upper limbs using the FEMS Program, hi addition, wheelchair driving feasibility at the optimized seating positions was verified from the average velocity and heart rate during slope ascension. Thus, the FEMS Program may be of use when prescribing a manual wheelchair.
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Yoshinobu Murakami, Toru Oshima, Kiyoshi Toriumi
Article type: Article
Session ID: 530
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Robots have one motor at each joint, but animals have bi-articular muscle driving two joints simultaneously. The bi-articular muscle characterizes animals and is predicted to have special functions. To clarity these functions, a simple human model was emploved. Gastrocnemius, the bi-articular muscle in the lower leg, was modeled simply by wire. The clarified bi-articular muscle functions will contribute to development of simple controlled robots. Computer simulations and model experiments were executed with the bi-articular muscle. The bi-articular muscle (1) controlled the direction of the ground reaction force, (2) stabilized jumping posture. These functions of the bi-articular muscle were applied to the leg orthosis.
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Dai NAKAI, Toru OSHIMA, Noboru MOMOSE, Tomohiko FUJIKAWA, Yukio SAITO, ...
Article type: Article
Session ID: 531
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This research aims to develop the lower limbs externally powered orthosis which makes it possible to re-acquire walking operation by the walking training with the orthosis by making the actuator arrangement of the orthosis for the training human-mimetic. Therefore, we examine the actuator arrangement theoretically and experimentally by the functionally effective muscle theory which was built based on the muscle arrangement of the leg.
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Yuta NAKASHIMA, Takashi YASUDA
Article type: Article
Session ID: 532
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper presents the fabrication and testing of a microfluidic device having a hydrophobic passive microvalve and a nano-hole array for releasing NGF (Nerve Growth Factors). This device was realized by processing a SOI (Silicon on Insulator) substrate. The microvalve was constructed in a cannel and driven by inlet pressure. It is possible to control NGF release precisely by opening and closing the microvalve. The nano-hole array was fabricated in a SiO_2 membrane of 500 nm in thickness using FIB (Focused Ion Beam) etching. Each nano-hole measures 500 nm in diameter, and is smaller than the diameter of an axon terminal. Experiments using a fluorescent solution showed that chemical release through the nano-holes was successfully controlled by opening and closing the microvalve. This result suggests that the fabricated device can axonal guidance by controlling release of NGF.
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Eiji SAKAI, Toshinori WATANABE
Article type: Article
Session ID: 533
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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To clarify flow phenomena in avian lung, oscillatory flow in a right angle branch was numerically studied in the range of dimensionless tidal volume, v_γ/a^3, of 10 to 80, and dimensionless frequency, α^2, of 8 to 40. The results show that the pressure drop caused by separation vortex at the entrance of side-daughter tube in the inspiratory phase drives unidirectional (circular) flow from the side-daughter tube to the daughter tube. Due to convective inertia, the unidirectional flow persists even in the expiratory phase, in which no vortex exists at the entrance of the side-daughter tube. By visualizing the streaming of fresh gas inspired from the mother tube, it is also shown that the unidirectional flow strongly enhances axial gas transportation in the process of avian respiration.
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Toshinosuke AKUTSU, Souya SAKURAI, Takamasa FUKUDA
Article type: Article
Session ID: 534
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Two typical mechanical heart vales (the St. Jude Medical and the Jyros valves) have been tested in the mitral position under pulsatile flow condition. The test program included measurements of velocity turbulent flow stress and turbulent intensity. The study was carried out using a sophisticated cardiac simulator in conjunction with a high resolution time resolved-Particle Image Velocimetry system.
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Kei KOSUGI, Hiromu HASHIMOTO
Article type: Article
Session ID: 535
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The influence of Reynolds number on the lift coefficient of dragonfly's wing is examined by the wind tunnel experiment by changing the attack angle of wing from -90deg to +90deg. Moreover, the artificial wings, which materials are plastic plate and cellophane sheet, are also used for the measurement of lift coefficient. It follows that the influence of Reynolds number on the dragonfly's wing is significant but the influence on the artificial wings is insignificant.
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Chihiro SAKAKIBARA, Kenkichi OHBA, Tsutomu TAJIKAWA, Katsuhiro HIGUCHI
Article type: Article
Session ID: 536
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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In a human body, erythrocytes deform highly and can smoothly pass capillaries which diameters are narrower than cells', Since capillaries connect all organs in a body, decrease in erythrocytes deformability causes several diseases. So it is very important to evaluate the dynamic deformability of the erythrocyte on a micfocirculation level. In this research, we produced the micro channel array with a 5umx5um square cross section of 100μm in length on the silicone chip to simulate capillaries, and made experiments to estimate the deformation of erythrocyte which flows channels. After whole blood was centrifuged erythrocytes from plasma, the erythrocytes were diluted with ACD-solution or plasma by a hematocrit of 10%. Each suspension was made to flow through the micro channels on the day of drawing blood and 2 days later. As a result, it is found that an erythrocyte whose shape looked like a parachute did not deform the whole body but only the rear side of the cell
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Youhei YAMAUCHI, Kenkichi OHBA, Tsutomu TAJIKAWA
Article type: Article
Session ID: 537
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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Capillaries are microvessels of 5〜8μm in diameter, and in the capillary vessels it is known that gas and mass exchanges playing an important role to live is done between red blood cells and tissue cells. Therefore study on blood flow in the capillaries is important. In order to clarify the blood flow in capillaries, we fabricated a realistic model of a capillary vessel in a silica glass by a femtosecond laser microfabrication system which had capability to fabricate three-dimensional microtube and microcavity inside a transparent material. The present capillary model has a straight hole of 10μm in diameter and of 100μm in length. We were able to observe the blood flow in this micro-model.
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Shinnichi IIDA, Kenkichi OHBA, Tsutomu TAJIKAWA, Masataka YOSHIDA, Fuy ...
Article type: Article
Session ID: 538
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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One of the known cure for ascending aortic aneurysm is the vascular grafting surgery using composite graft. However, almost all conservative grafts don't have Valsalva sinus, and influence of the existence of the Valsalva sinus has not been clarified. In order to understand the effect of the Valsalva sinuses, some realistic models of aortic valve were manufactured. In this study, we have produced modeled aortic valves by using three-dimensional modeling machine, and have investigated the effect of its existence and the leading angle of coronary artery on blood flow and the flow field in the Valsalva sinus. As the result, it was found that the amplitude of coronary flow rate in the model with Valsalva sinus is smaller than that of the model without Valsalva sinus and that displacement of the valve leaflet of which the model has Valsalva sinus is smaller than that of model without Valsalva sinus.
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Masaaki TAMAGAWA, Sumiaki MATSUO, Aiko WATANABE
Article type: Article
Session ID: 539
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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This paper describes a numerical prediction method for thrombus formation in blood flows using Lattice Boltzmann Method (LBM) and Finite Difference Method (FDM). In this study, the now around a cylinder between two plates to compare the prediction experiment by Liu et al. Using these database, quantity of thrombus is predicted by integrating (l) transport equation for concentration of blood coagulation factor and (2) shear velocity, and (3) wall distance. It is concluded that the trend to have thrombus formations around the cylinder is similar to the experiments, but the prediction model is not complete.
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Tetsuya YANO, Ayumi Mitoh, Kazumitsu SEKINE, Yoshinori MITAMURA, Ikuya ...
Article type: Article
Session ID: 540
Published: September 04, 2004
Released on J-STAGE: August 01, 2017
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The successful use of a continuous flow blood pump depends on the degree of blood trauma. A major cause of blood trauma is the mechanical stress acting on the corpuscles passing through the pump, hi this study, assuming that the red blood cells passed along the streamlines, a blood damage index was calculated based on the changes in shear stress with time along streamlines starting from entrance plane of the pump. Indices of hemolysis should be estimated by analysis under the same operating conditions (i.e. flow rate and pressure head) to compare the hemolysis levels of different pumps The preliminary analyses for deriving the rotational speed conditions obtaining 5L/min of flow rate and 100mmHg pressure head, and final analysis for estimating the hemolysis index were automated. This estimation method of hemolysis is a useful tool for design modification of blood pumps.
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