KINDAI UNIVERSITY


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YAMAMOTO Ei

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FacultyDepartment of Biomedical Engineering / Graduate School of Biology-Oriented Science and Technology
PositionAssociate Professor
Degree
Commentator Guidehttps://www.kindai.ac.jp/meikan/1201-yamamoto-ei.html
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Last Updated :2020/09/02

Education and Career

Education

  •  - 1998 , Osaka University
  •  - 1998 , Osaka University, Graduate School of Engineering Science
  •  - 1993 , Kyushu Institute of Technology, School of Computer Science and Systems Engineering
  •  - 1993 , Kyushu Institute of Technology, Faculty of Computer Science and Systems Engineering

Academic & Professional Experience

  •   2002 ,  - 2003 , University of California, Berkeley
  •   1998 ,  - 2002 , Faculty of Biology-Oriented Science and Technology, Kindai University
  •   2002 ,  - 2003 , Visiting Research Fellow, University of California
  •   2003 , - Lecturer, Kinki University
  •   1998 ,  - 2002 , Research Associate, Kinki University.

Research Activities

Research Areas

  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Machine materials and mechanics
  • Life sciences, Biomaterials
  • Life sciences, Biomedical engineering

Research Interests

  • Biomechanics

Published Papers

  • Changes in the structure and mechanical properties of bone tissues obtained from experimental animal models of lifestyle-related diseases, Yamamoto, E, Kawamura, Y, Journal of Mechanical Engineering (JMechE), Journal of Mechanical Engineering (JMechE), 5, 226 - 234, Feb. 2018 , Refereed
  • Optimization of humid conditions using an ultrasonic nebulizer for the fabrication of hydroxyapatite film with the Er:YAG laser deposition method, Yamamoto, E, Kato, N, Hatoko, Y, Hontsu, S, Key Engineering Materials, Key Engineering Materials, 720, 268 - 274, Nov. 2016 , Refereed
  • Preparation and evaluation of potassium-containing hydroxyapatite sheet for dentin hyperesthesia treatment, HATOKO YUKA, YAMAMOTO EI, KATO NOBUHIRO, NISHIKAWA HIROAKI, YOSHIKAWA KAZUSHI, FURUZONO TSUTOMU, YAMAMOTO KAZUYO, HONTSU SHIGEKI, 日本歯科理工学会誌, 日本歯科理工学会誌, 34(5), 416, Sep. 15 2015
  • in vivoで骨形成を誘導する低接着性コラーゲンの効果, MORIMOTO KOICHI, KUNII SAORI, HORIUCHI YOSHITAKA, AKABOSHI YASUMITSU, IDA MASATAKA, HIRAOKA YOSUKE, ITO HIROYUKI, YAMAMOTO EI, 再生医療, 再生医療, 14, 222, Feb. 01 2015
  • Direct Deposition of an Apatite Film on Dentin Using the Er:YAG Laser-Ablation Method, HONTSU Shigeki, YAMAMOTO Ei, KATO Nobuhiro, YOSHIKAWA Kazushi, YASUO Kenzo, YAMAMOTO Kazuyo, Journal of Japanese Society for Laser Dentistry, Journal of Japanese Society for Laser Dentistry, 26(1), 10 - 16, 2015
    Summary:Ideal restoration of tooth substances requires hydroxyapatite (HAp), of which the tooth is composed. However, restoration treatment with HAp is not yet possible, as adherence to ceramics is very difficult. In the present study, we examined a tooth restoration technique using the intraoral laser ablation method. A thin layer of α-tricalcium phosphate (α-TCP) was deposited on the dentin surface by the ablation phenomenon using an Er:YAG laser, which has already been introduced into dental treatment, to irradiate the target α-TCP. The deposited layer was then hydrolyzed by dripping pure water on its surface in order to create a hydroxyapatite (HAp) coating. In this study, we developed a compact pulsed laser deposition (PLD) system using the Er:YAG laser. The interface structure between the HAp coating and the dentin surface was observed by scanning electron microscope (SEM). Electron micrographs showed that the HAp layer was formed on the dentin surface. Moreover, dentinal tubules were sealed with HAp particles. We evaluated the blockade effect of dentinal tubules using Pashle's method. The measured average value for the sealing rate of the dentinal tubules was 85.6±8.6%, which was greater than the value with resin coating treatment. The adhesive strength of HAp films deposited on dentin was evaluated by quasi-static tensile tests. On mechanical evaluation, the adhesive strength was greater than 3.8 MPa. The present results suggest that this technique will be useful for the repair of dentin and the treatment of hyperaesthesia.
  • Ultrathin amorphous calcium phosphate freestanding sheet for dentin tubule sealing, Kato, N, Yamamoto, E, Isai, A, Nishikawa, H, Kusunoki, M, Yoshikawa, K, Hontsu, S, Bioceramics Development and Applications, Bioceramics Development and Applications, S1 - S007, Dec. 2013 , Refereed
  • Restoration of tooth enamel using a flexible hydroxyapatite sheet coated with tricalcium phosphate, Yamamoto, E, Kato, N, Isai, A, Nishikawa, H, Kusunoki, M, Yoshikawa, K, Hontsu, S, Bioceramics Development and Applications, Bioceramics Development and Applications, S1 - S006, Dec. 2013 , Refereed
  • Characterization of damage process of rabbit tendon by acoustic emission technique in vitro, Sakai, T, Suzuki, S, Wakayama, S, Yamamoto, E, Journal of Japanese Society for Experimental Mechanics, Journal of Japanese Society for Experimental Mechanics, 13, s213 - s216, Sep. 2013 , Refereed
  • バイオメカニクスにおける新たな計測技術 生体内で腱・靭帯に作用する張力の測定, YAMAMOTO EI, 非破壊検査, 非破壊検査, 60(11), 626 - 629, Nov. 01 2011
  • Growth-related changes in the mechanical properties of collagen fascicles from rabbit patellar tendons, E Yamamoto, W Iwanaga, N Yamamoto, K Hayashi, BIORHEOLOGY, BIORHEOLOGY, 41(1), 1 - 11, 2004 , Refereed
    Summary:Growth-related changes in the mechanical properties of collagen fascicles (approximately 300 mum in diameter) were studied using patellar tendons obtained from skeletally immature 1 and 2 months old and matured 6 months old rabbits. Tensile properties were determined using a specially designed micro-tensile tester. In each age group, there were no significant differences in the properties among cross-sectional locations in the tendon. Tangent modulus and tensile strength significantly increased with age; the rates of their increases between 1 and 2 months were higher than those between 2 and 6 months. The tangent modulus and tensile strength were positively correlated with the body weight of animals. However, growth-related changes in the mechanical properties were different between collagen fascicles and bulk patellar tendons, which may be attributable to such non-collagenous components as ground substances and also to mechanical interactions between collagen fascicles.
  • Adhesive evaluation by brushing tests for hydroxyapatite films fabricated on dentins using a water mist assisted Er:YAG laser deposition method, Ei Yamamoto, Nobuhiro Kato, Shigeki Hontsu, Key Engineering Materials, Key Engineering Materials, 758, 97 - 104, 2017 , Refereed
    Summary:Hydroxyapatite (HAp) is one of the main structural components in tooth. Therefore, the HAp is an ideal material to repair tooth substances. However, it has not yet been realized that tooth enamel and dentin are artificially repaired using the HAp in operative dentistry. We have proposed and developed a tooth restoration technique with intraoral laser ablation using an Er:YAG (Erbium: Yttrium-Aluminum-Garnet) laser in order to fabricate HAp films on tooth surfaces in the atmosphere at room temperature. Although HAp thin films were formed on dentin surfaces using the Er:YAG laser deposition method, it has still been unclear how is the mechanical durability of the HAp film on tooth substances. In the present study, we conducted brushing tests to evaluate the durability of adhesion between the HAp film and dentin. To form HAp layers on dentin surfaces, an ablation phenomenon was induced by the Er:YAG laser irradiated to the target of α-Tricalcium phosphate (α-TCP) under humid conditions. The deposited layers were hydrolyzed by dripping artificial saliva on the surface at 37 degrees Celsius for 24, 48, 72, 120, and 168 hours to create HAp films. The films hydrolyzed for more than 48 hours were attached on the dentin surface after the brushing tests. This result indicates that the α-TCP layer deposited on the dentin surface changes into a crystallized HAp material by the hydrolyzation for more than 48 hours. The crystallization of the film possibly contributes to the high adhesive durability of the HAp film deposited on the dentin.
  • Development of ultra-Thin opaque white hydroxyapatite sheet for restoration of enamel and aesthetic treatments of teeth, Nobuhiro Kato, Yuki Ido, Ei Yamamoto, Shigeki Hontsu, Key Engineering Materials, Key Engineering Materials, 758, 162 - 165, 2017 , Refereed
    Summary:In cosmetic dentistry, bleaching and laminate veneer methods are common treatments to improve the appearance of teeth. However, there are limitations to these treatments, as they damage the enamel which is not capable of recovering naturally. In this study, novel hydroxyapatite (HAp) sheets, which enable both enamel restoration and aesthetic treatments, were developed. Results indicated that the lower range of the sintering temperatures, of the pulsed laser deposition targets, produced lighter shades of amorphous calcium phosphate (ACP) sheets. Subsequently, the post-Annealing process of the sheets induced crystallization processes of the ACP sheets, to form HAp sheets, and improved the shade rank of the sheet. The shade rank of the developed sheet (6.8 ± 0.2) was almost comparable to the average shade rank of the teeth of Japanese people, within a range of 6.5 to 7.0.
  • Preparation and application of a potassium-substituted calcium phosphate sheet as a dental material for treating dentin hypersensitivity, Nobuhiro Kato, Yuka Hatoko, Ei Yamamoto, Tsutomu Furuzono, Shigeki Hontsu, Key Engineering Materials, Key Engineering Materials, 720, 102 - 107, 2017 , Refereed
    Summary:Potassium-substituted calcium phosphate free standing sheet for the treatment of dentin hypersensitivity was prepared and evaluated. The appropriate annealing condition for the target of pulsed laser deposition to prepare the potassium-substituted amorphous calcium phosphate (PS-ACP) sheet was investigated. The target annealed at 1000 �C was used to deposit the PS-ACP sheet. The annealing condition for the potassium-substituted hydroxyapatite (PS-HAp) sheet was evaluated by XRD and EDX. The potassium release rate from PS-ACP sheet in PBS, evaluated by ICP-MS, was 2.5 times larger than that of PS-HAp sheet. The robustness of the PS-ACP sheet was proved by the brushing test of the PS-ACP sheet affixed on a bovine dentin. The dentin tubules on the dentin surface was occluded by the PS-ACP sheet and which confirmed by SEM observations.
  • Adhesion properties of an apatite film deposited on dentine using Er:YAG Laser ablation method, Ei Yamamoto, Nobuhiro Kato, Kazushi Yoshikawa, Kenzo Yasuo, Kazuyo Yamamoto, Shigeki Hontsu, Key Engineering Materials, Key Engineering Materials, 696, 69 - 73, 2016 , Refereed
    Summary:Tooth enamel cannot be naturally reconstructed once it is destroyed immoderately. Therefore, the restoration of enamel is important in dental treatment. Hydroxyapatite (HAp) can potentially be used for a novel dental biomaterial to repair the enamel. We have proposed a tooth restoration technique with intraoral laser ablation method. A thin layer of HAp was deposited on dentin surface in the atmosphere by ablation phenomenon using an Er:YAG (Erbium: Yttrium-Aluminum-Garnet) laser irradiated to the target of α-Tricalcium phosphate (α-TCP). Then, the deposited layer was hydrolyzed by dripping pure water on its surface in order to create HAp film. The adhesive strength between the HAp film and dentin was evaluated by quasi-static tensile tests. As a result of the mechanical evaluation, the adhesive strength was greater than approximately 3.8 MPa. It is clear that the HAp film created by the Er:YAG laser ablation method is attached tightly to the dentin.
  • Overlaid ultrathin amorphous calcium phosphate sheet improves dentinal permeability inhibition rate, Nobuhiro Kato, Yuki Ido, Ei Yamamoto, Kenzo Yasuo, Kazushi Yoshikawa, Shigeki Hontsu, Key Engineering Materials, Key Engineering Materials, 696, 99 - 102, 2016 , Refereed
    Summary:Dentin hypersensitivity is induced by mechanical stimuli or heat stimuli applied via exposed dentin tubules. Resin coating and laser-irradiation are used for treatment but have some problems such as poor biocompatibility or difficulty for laser power setting. We have been developing a treatment that creates artificial tooth enamel by attaching flexible ultrathin calcium phosphate sheet to seal the dentin tubule orifice. In this study, the quantitative evaluation of dentinal permeability inhibition rate (DPIR) improved by attaching ultrathin amorphous calcium phosphate (APC) sheets on human dentin in vitro is presented. The obtained DPIR by overlaid APC sheets application was 81.1 ± 5.7 %.
  • Prophylactic effects of elastin peptide derived from the bulbus arteriosus of fish on vascular dysfunction in spontaneously hypertensive rats, Kumiko Takemori, Ei Yamamoto, Hiroyuki Ito, Takashi Kometani, LIFE SCIENCES, LIFE SCIENCES, 120, 48 - 53, Jan. 2015 , Refereed
    Summary:Aims: To determine the prophylactic effects of an elastin peptide derived from the bulbus arteriosus of bonitos and prolylglycine (PG), a degradation product of elastin peptide, on vascular dysfunction in spontaneously hypertensive rats (SHRs). Main methods: Male 15-week-old SHR/Izm rats were fed without (control group) or with elastin peptide (1 g/kg body weight) for 5 weeks (EP group), or were infused via an osmotic mini-pump for 4 weeks with PG (PG group) or saline (control group). Using thoracic aortas, we assessed endothelial changes by scanning electron microscopy. Vascular reactivity (contraction and relaxation) and pressure-induced distension was compared. mRNA production levels of endothelial nitric oxide synthase (eNOS) and intercellular adhesion molecule-1 (ICAM-1) were investigated by real-time-polymerase chain reaction. Key findings: Aortas of the EP group displayed limited endothelial damage compared with that in the control group. Under treatment of SHRs with elastin peptide, the effect of phenylephrine returned closer to the normal level observed in normotensive Wistar-Kyoto (WKY/Izm) rats. mRNA production of eNOS (but not ICAM-1) was greater in the EP group than in the control group. Endothelial damage was suppressed and pressureinduced vascular distension was greater in the PG group than in the corresponding control group. Significance: These results suggest that elastin peptide from bonitos elicits prophylactic affects hypertensionassociated vascular dysfunction by targeting the eNOS signaling pathway. PG may be a key mediator of the beneficial effects of elastin peptide. (C) 2014 Elsevier Inc. All rights reserved.
  • Evaluation of dentin tubule sealing rate improved by attaching ultrathin amorphous calcium phosphate sheet, Nobuhiro Kato, Arata Isai, Ei Yamamoto, Hiroaki Nishikawa, Masanobu Kusunoki, Kazushi Yoshikawa, Kenzo Yasuo, Kazuyo Yamamoto, Shigeki Hontsu, Key Engineering Materials, Key Engineering Materials, 631, 258 - 261, 2015 , Refereed
    Summary:Dentin hypersensitivity is induced by mechanical stimuli or heat stimuli applied via dentin tubules exposed by lost of dental enamel or gingival recession. Common treatments for dentin hypersensitivity are resin coating or laser irradiation. However, these treatments have some problems such as poor biocompatibility or insufficient durability. We have been developing a treatment that creates artificial tooth enamel by attaching flexible ultrathin calcium phosphate sheet having a crystal structure similar to that of tooth enamel to seal the dentin tubules. In this study, the quantitative evaluation of dentin tubule sealing rate improved by attaching ultrathin amorphous calcium phosphate (ACP) sheet on human dentin is presented. The obtained sealing-rate by APC sheet application was 70.9 ±4.8%.
  • A novel treatment for dentine cavities with intraoral laser ablation method using an Er:YAG laser, Ei Yamamoto, Nobuhiro Kato, Arata Isai, Hiroaki Nishikawa, Yoshiya Hashimoto, Kazushi Yoshikawa, Shigeki Hontsu, Key Engineering Materials, Key Engineering Materials, 631, 262 - 266, 2015 , Refereed
    Summary:It has been well known that bone has piezoelectric properties and these properties have been considered to be caused by the shift of the center of symmetry of the positive and negative electrical charge due to the strain of the collagen fibers included in the bone. Thus, it has long been considered that there were no piezoelectric effects in the hexagonal hydroxyapatite(HAp) which has center of symmetry of crystal. However, in recent years, the piezoelectric property of artificially synthesized HAp was reported. In the authors' previous report, a new result which showed the piezoelectricity of the hydroxyapatite(HAp) films fabricated by the pulsed laser deposition(PLD) method was reported. In this study, the effect of poling treatment on piezoelectric constant of pulsed laser deposited HAp films was investigated.
  • Adhesive Strength between Flexible Hydroxyapatite Sheet and Tooth Enamel, E. Yamamoto, N. Kato, H. Nishikawa, M. Kusunoki, T. Hayami, K. Yoshikawa, S. Hontsu, BIOCERAMICS 24, BIOCERAMICS 24, 529-530, 522 - +, 2013 , Refereed
    Summary:Tooth enamel cannot be reconstructed once it is destroyed immoderately. Hydroxyapatite (HAp) thin sheet can potentially be used for a novel dental biomaterial to repair the enamel. Using a pulsed laser deposition (PLD) method, we have successfully created a flexible HAp sheet of less than a few micrometers in thickness. Due to its flexibility, the HAp sheet is tightly adhered on curved surfaces at the target site. In the present study, we newly developed double-layered sheets composed of HAp film coated with tricalcium phosphate (TCP) thin layer. The HAp/TCP sheet was adhered to the extracted human teeth using a calcium phosphate solution for 3 days. The adhesive strength between the HAp/TCP sheet and tooth enamel was evaluated by quasi-static tensile tests. Moreover, the interface structure between them was observed by a scanning electron microscopy. As a result of the mechanical evaluation, the adhesive strength was greater than approximately 2.5 MPa. The electron microscopic observation revealed that the sheet was partially fused with the enamel. These findings suggest the possibility that enamel defects are repaired using the HAp/TCP sheet for a short duration.
  • Regeneration of tooth enamel by flexible hydroxyapatite sheet, S. Hontsu, N. Kato, E. Yamamoto, H. Nishikawa, M. Kusunoki, T. Hayami, K. Yoshikawa, Key Engineering Materials, Key Engineering Materials, 493-494, 615 - 619, 2012 , Refereed
    Summary:Before a tooth erupts, the ameloblasts are lost, which means that the tooth enamel does not regenerate itself after tooth eruption. In the present study, we attempt to regenerate the tooth enamel artificially using a flexible hydroxyapatite (HAp) sheet. First, a HAp film was deposited on a soluble substrate by pulsed laser deposition (PLD) using an ArF excimer laser. Next, the HAp film was collected as a freestanding sheet by dissolving the substrate using a solvent. The HAp sheet was adhered to the extracted human teeth using a calcium phosphate solution. The variation of the crystal structure of the HAp sheet with time was investigated by X-ray diffraction analysis. Furthermore, the variation in the mechanical characteristics with time between the HAp sheet and dental enamel were evaluated using tensile and scratch tests. The results suggest that the HAp sheet became fused to the tooth enamel within approximately one week. © (2012) Trans Tech Publications.
  • Effects of non-destructive overloading on the mechanical properties, microstructure and ultrastructure of Rabbit Patellar Tendons, Ei Yamamoto, Kousuke Ohta, Journal of Biomechanical Science and Engineering, Journal of Biomechanical Science and Engineering, 4(4), 539 - 549, 2009 , Refereed
    Summary:Incomplete or subfailure injuries of tendons occur more frequently than their complete ruptures. However, the mechanical behavior of the incompletely injured tissues is poorly understood. In the present study, we quantified the mechanical properties, microstructure, and ultrastructure of rabbit patellar tendons subjected to non-destructive overloading. No significant changes in the mechanical properties were observed in the tendon specimens which were applied a subfailure stretch equivalent to 80% of the failure stress of the control tendons at a low strain rate (1.67 %/sec). There was a significant decrease not in the tensile strength but in the tangent modulus of the specimens when they were subjected to 90% of the control failure stress at the low rate. For the same level of overloading at a high strain rate (16.7 %/sec), both the modulus and strength of the overloaded specimens were significantly lower than those of the control ones. Microstructually, irrespective of the strain rate, crimped collagen fibers in the overloaded tendons were straightened by the 90% overloading. In contrast, adverse alterations in the ultrastructure were induced by the 90% overloading only at the high rate. These results indicate that tendinous tissues have potential capacities to maintain the original strength if a relatively high overload is monotonically applied at lower strain rates. However, it is possible that subfailure overloads delivered at higher strain rates produce more severe changes in the properties and structures of the tissues.
  • Biomechanical response of collagen fascicles to restressing after stress deprivation during culture, Ei Yamamoto, Daisuke Kogawa, Susumu Tokura, Kozaburo Hayashi, JOURNAL OF BIOMECHANICS, JOURNAL OF BIOMECHANICS, 40(9), 2063 - 2070, 2007 , Refereed
    Summary:In vitro tissue culture experiments were performed to study the biornechanical response of collagen fascicles to restressing after exposure to non-loaded condition. Collagen fascicles of approximately 300 mu m in diameter were aseptically dissected from rabbit patellar tendons. They were cultured under no-load condition for I week, and then under a static stress of approximately 1.2 MPa for the subsequent I or 2 weeks. After culture, their mechanical properties were determined with a micro-tensile tester, and were compared to those of fascicles cultured under no-load condition and non-cultured, control fascicles. Tangent modulus and tensile strength of the nonloaded fascicles were significantly lower than those of the control fascicles at I week and gradually decreased thereafter. However, the modulus and strength were increased by restressing. After 2-week restressing, both parameters were significantly greater than those of the time-matched, non-loaded fascicles, although these values were still significantly lower than those of the control fascicles. That is, the application of stress after exposure to non-loaded condition suppressed the deterioration of the biomechanical properties of fascicles, although it did not improve. These results indicate that a short period of stressing is not sufficient for cultured collagen fascicles to completely recover their mechanical properties, if they are once exposed to no-stress condition even for a short period of time. These are similar to previous results observed in tendons and ligaments inside the body. (C)2006 Elsevier Ltd. All rights reserved.
  • Ex vivo infiltration of fibroblasts into the tendon deteriorates the mechanical properties of tendon fascicles but not those of tendon bundles, Yasunari Ikema, Harukazu Tohyama, Ei Yamamoto, Fuminori Kanaya, Kazunori Yasuda, CLINICAL BIOMECHANICS, CLINICAL BIOMECHANICS, 22(1), 120 - 126, Jan. 2007 , Refereed
    Summary:Background After ligament reconstruction, mechanical deterioration of the grafted tendon is observed with revascularization and cellular infiltration. However, the effect of cellular infiltration on the mechanical properties of the tendon matrix has not been fully understood. Methods. Cultured fibroblasts derived from the rabbit patellar tendon were seeded around an acellular rabbit patellar tendon that had undergone freeze-thaw treatment. At time-0, 3, and 6 weeks after seeding the cells, we evaluated cellular distribution in the tendon using a confocal laser microscope and the mechanical evaluations of the tendon fascicles and the tendon bundles. Findings. The confocal laser microscopic analysis showed fibroblast infiltration ex vivo into the acellular tendon matrix. We could not find significant effects of the cellular infiltration on the tangent modulus of the tendon bundle, although the ex vivo cellular infiltration significantly reduced the modulus of the tendon fascicle. In addition, the tangent modulus of the incubated tendon without fibroblasts significantly decreased with time, particularly in the tendon bundle levels. Interpretation. The findings of this study suggested that the effects of ex vivo cellular infiltration on the mechanical properties of the tendon bundles are relatively small, compared with its striking effect on the tendon fascicles. (c) 2006 Elsevier Ltd. All rights reserved.
  • Development of residual strains in human vertebral trabecular bone after prolonged static and cyclic loading at low load levels, Ei Yamamoto, R. Paul Crawford, Deva D. Chan, Tony M. Keaveny, JOURNAL OF BIOMECHANICS, JOURNAL OF BIOMECHANICS, 39(10), 1812 - 1818, 2006 , Refereed
    Summary:Development of irreversible residual strains in trabecular bone may be a mechanism by which age-related non-traumatic vertebral fractures occur. To investigate this concept, static and cyclic loading tests were conducted at low loading levels for cylindrical cores of cadaveric vertebral trabecular bone. Stresses were applied equivalent to elastic strains of either 750 or 1500 microstrain. Creep strains were measured during the tests, which lasted for 125,000 seconds (about 35 h), and for an additional 125,000 seconds after complete unloading. Emphasis was placed on the residual strains that developed, defined as the strain remaining at the end of the unloading phase. The results indicated that appreciable residual strains did develop, and were similar for static and cyclic loading. Irrespective of the applied load levels and loading modes, the residual strains that remained after the unloading phase were similar in magnitude to the originally applied elastic strain. Extrapolation of the observed residual strains to full recovery indicated that the time that would be required for full recovery was over 20 times longer than the duration of the applied loads. These results indicate that human vertebral trabecular bone does not creep in a linear viscoelastic fashion at low stress levels, and that creep mechanisms dominate the residual strains regardless of the loading mode. Taken together, these findings support the concept that non-traumatic vertebral fractures may be related to long-term creep effects because the trabecular bone does not have sufficient time to recover mechanically from creep deformations accumulated by prolonged static or cyclic loading. (c) 2005 Elsevier Ltd. All rights reserved.
  • Effects of the frequency and duration of cyclic stress on the mechanical properties of cultured collagen fascicles from the rabbit patellar tendon, E Yamamoto, D Kogawa, S Tokura, K Hayashi, JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME, JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME, 127(7), 1168 - 1175, Dec. 2005 , Refereed
    Summary:The effects of frequency or duration of cyclic stress on the mechanical properties of collagen fascicles were studied by means of in vitro tissue culture experiments. Collagen fascicles of approximately 300 mu m in diameter were obtained from rabbit patellar tendons. During culture, cyclic stress having the peak stress of approximately 2 MPa was applied to the fascicles at 1 Hz for 1 hour/day (1 Hz-1 h group), at I Hz for 4 hours/day (1 Hz-4 h group), or at 4 Hz for 1 hour/day (4 Hz-1 h group). The frequency of 4 Hz and the duration of 1 hour/day are considered to be similar to those of the in vivo stress applied to fascicles in the intact rabbit patellar tendon. After culture for 1 or 2 weeks, the mechanical properties of the fascicles were determined using a microtensile tester and were compared to the properties of non-cultured, fresh fascicles (control group) and the fascicles cultured under no load condition (non-loaded group). The tangent modulus and tensile strength of fascicles in the 4 Hz-1 h group were similar to those in the control group; however, the fascicles of the 1 Hz-1 h and 1 Hz-4 h groups had significantly lower values than those of the control group. There was no significant difference in the tensile strength between the 1 Hz- 1 h and non-loaded groups, although the strength in the 1 Hz-4 It group was significantly higher than that of the non-loaded group. It was concluded that the frequency and duration of cyclic stress significantly affect the mechanical properties of cultured collagen fascicles. If we apply cyclic stress having the frequency and duration which are experienced in vivo, the biomechanical properties are maintained at control, normal level. Lower frequencies or less cycles of applied force induce adverse effects.
  • Effects of cyclic stress on the mechanical properties of cultured collagen fascicles from the rabbit patellar tendon, E Yamamoto, S Tokura, K Hayashi, JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME, JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME, 125(6), 893 - 901, Dec. 2003 , Refereed
    Summary:Effects of cyclic stress on the mechanical properties of collagen fascicles were studied by in vitro tissue culture experiments. Collagen fascicles (approximately 300 mum in diameter) obtained from the rabbit patellar tendon were applied cyclic load at 4 Hz for one hour per day during culture period for one or two weeks, and then their mechanical properties were determined using a micro-tensile tester There was a statistically significant correlation between tensile strength and applied peak stress in the range of 0 to 5 MPa, and the relation was expressed by a quadratic function. The maximum strength (19.4 MPa) was obtained at the applied peak stress of 1.8 MPa. The tensile strength of fascicles were within a range of control values, if they were cultured under peak stresses between 1.1 and 2.6 MPa. Similar results were also observed in the tangent modulus, which was maintained at control level under applied peak stresses between 0.9 and 2.8 MPa. The stress of 0.9 to 1.1 MPa is equivalent to approximately 40% of the in vivo peak stress which is developed in the intact rabbit patellar tendon by running, whereas that of 2.6 to 2.8 MPa corresponds to approximately 120% of the in vivo peak stress. Therefore, the fascicles cultured under applied peak stresses of lower than 40% and higher than 120% of the in vivo peak stress do not keep the original strength and modulus. These results indicate that the mechanical properties of cultured collagen fascicles strongly depend upon the magnitude of the stress applied during culture, which are similar to our previous results observed in stress-shielded and overstressed patellar tendons in vivo.
  • The changes in mechanical properties of regenerated and residual tissues in the patellar tendon after removal of its central portion, H Tohyama, K Yasuda, Y Kitamura, E Yamamoto, K Hayashi, CLINICAL BIOMECHANICS, CLINICAL BIOMECHANICS, 18(8), 765 - 772, Oct. 2003 , Refereed
    Summary:Objective. To know the temporal changes of the mechanical properties of the regenerated and the residual tissues in the patellar tendon after removal of the central portion. Design. The regenerated and the residual tissues were compared to sham-operated tendons. Background. Although the structural properties of the whole patellar tendon after removal of the central portion have been investigated. no studies have distinguished between the regenerated and the residual tissues. Methods. For 52 skeletally mature rabbits, a full-thick, segmental defect was made at the central portion of the right patellar tendon, while a sham operation performed in the left tendon. At 3, 6, 12, and 24 weeks, we evaluated the mechanical properties and fibroblast density of the regenerated and the residual tissues as well as the blood flow and tissue dimensions of the patellar tendon. In addition, non-treated patellar tendons from six rabbits were served as the control for mechanical testing. Results. The tangent modulus and the tensile strength of the regenerated tissue progressively increased with time. On the other hand, these parameters of the residual tendinous portion decreased until 6 weeks, although they gradually increased thereafter. The tensile strength of the regenerated and the residual tissues at 24 weeks were approximately 80% and 75%, respectively, of the non-treated. control tendon. Abundant blood flow and cell proliferation were observed in the regenerative tissue until 6 weeks. Conclusion. The mechanical properties of the regenerated and the residual tissues after removal of the central portion in the patellar tendon are much different from those of the original tendon.
  • Effects of static stress on the mechanical properties of cultured collagen fascicles from the rabbit patellar tendon, E Yamamoto, W Iwanaga, H Miyazaki, K Hayashi, JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME, JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME, 124(1), 85 - 93, Feb. 2002 , Refereed
    Summary:In-vitro tissue culture experiments were performed to study the effects of static stress on the mechanical properties of collagen fascicles obtained from the rabbit patellar tendon. After collagen fascicles having the diameter of approximately 300 mum were cultured for 1 and 2 wk under static stress between 0 and 3 MPa, their mechanical properties and cri. nip morphology were determined using a micro-tensile tester and a light microscope, respectively. The tensile strength and tangent modulus of the fascicles were significantly decreased by culture under no load compared to control fascicles. A statistically significant correlation, which was described by a quadratic curve, was observed between applied stress and tensile strength. The maximum tensile strength (16.7 MPa) was obtained at the applied stress of 1.2 MPa; the strength was within a range of control values. There was a similar correlation between applied stress and tangent modulus, and the modulus was maintained at control level under 1.3 MPa stress. The stress of 1.2 to 1.3 Alpa is equivalent to approximately 50 percent of the peak stress developed in the intact rabbit patellar tendon by running. Strain at failure of cultured collagen fascicles was negatively correlated with applied stress, and that at 1.2 to 1.3 MPa stress was almost the same as the control value. Crimp morphology in the fascicles cultured under about 1.2 MPa stress was similar to that in control fascicles. These results indicate that cultured collagen fascicles change the mechanical properties and structure in response to static tensile stress. In addition, their mechanical properties and structure are maintained at control level if the static stress of 50 percent of in-vivo peak stress is applied.
  • Mechanical properties of collagen fascicles from in situ frozen and stress-shielded rabbit patellar tendons, E Yamamoto, S Tokura, N Yamamoto, K Hayashi, CLINICAL BIOMECHANICS, CLINICAL BIOMECHANICS, 15(4), 284 - 291, May 2000 , Refereed
    Summary:Objective. To know the effects of stress shielding on the biomechanical properties of collagen fascicles obtained from in situ frozen patellar tendons (an autograft model). Design. Collagen fascicles of approximately 300 mu m in diameter tt ere obtained from in situ frozen rabbit patellar tendons and also from in situ frozen and stress-shielded ones, and their mechanical properties and fibroblast density were determined. Background Stress shielding changes the mechanical properties of in situ frozen patellar tendons in which there exist no fibroblasts, The mechanisms of this phenomenon have not been studied well. Method. Patellar tendon of both in situ frozen group and in situ frozen and stress-shielded group were frozen in situ by liquid nitrogen to kill fibroblasts. Then, in the in situ frozen and stress-shielded group, no tension was applied to the tendons for 2, 3, and 6 weeks, while normal tension was applied to the tendons of the in situ frozen group. Tensile properties of the collagen fascicles obtained from these tendons were determined using a microtensile tester, and were compared to the collagen fascicles from nonfrozen, stress-shielded patellar tendons. Results. Tangent modulus and tensile strength of collagen fascicles from the in situ frozen and stress-shielded group progressively decreased with the time of stress shielding; however, these decreases were much smaller than those of the fascicles obtained from non-frozen, stress-shielded tendons. Although there were few fibroblasts in the patellar tendon of the in situ frozen and stress-shielded group at 2 weeks, the modulus and strength of the fascicles from the posterior portion were significantly lower than those in the in situ frozen group. In addition, the reduction of strength caused by stress shielding was much smaller in collagen fascicles than in bulk patellar tendons. Conclusion. The mechanical properties of collagen fascicles in in situ frozen tendons (an autograft model) are affected by stress shielding even under acellular condition.
  • Effects of stress shielding on the transverse mechanical properties of rabbit patellar tendons, E. Yamamoto, K. Hayashi, N. Yamamoto, Journal of Biomechanical Engineering, Journal of Biomechanical Engineering, 122(6), 608 - 614, 2000 , Refereed
    Summary:With the aim of studying mechanisms of the remodeling of tendons and ligaments, the effects of stress shielding on the rabbit patellar tendon were studied by performing tensile and stress relaxation tests in the transverse direction. The tangent modulus, tensile strength, and strain at failure of non-treated, control patellar tendons in the transverse direction were 1272 kPa, 370 kPa, and 40.5 percent, respectively, whereas those of the tendons stress-shielded for 1 week were 299 kPa, 108 kPa, and 40.4 percent, respectively. Stress shielding markedly decreased tangent modulus and tensile strength in the transverse direction, and the decreases were larger than those in the longitudinal direction, which were determined in our previous study. For example, tensile strength in the transverse and longitudinal direction decreased to 29 and 50 percent of each control value, respectively, after 1 week stress shielding. In addition, the stress relaxation in the transverse direction of stress-shielded patellar tendons was much larger than that of non-treated, control ones. In contrast to longitudinal tensile tests for the behavior of collagen, transverse tests reflect the contributions of ground substances such as proteoglycans and mechanical interactions between collagen fibers. Ground substances provide lubrication and spacing between fibers, and also confer viscoelastic properties. Therefore, the results obtained from the present study suggest that ground substance matrix, and interfiber and fiber - matrix interactions have important roles in the remodeling response of tendons to stress.
  • Mechanical properties of collagen fascicles from stress-shielded patellar tendons in the rabbit, Ei Yamamoto, Kozaburo Hayashi, Noritaka Yamamoto, Clinical Biomechanics, Clinical Biomechanics, 14(6), 418 - 425, Jul. 1999 , Refereed
    Summary:Objective. To know the effects of stress shielding applied to the patellar tendon on the collagen fascicles. Design. The mechanical properties of collagen fascicles obtained from stress-shielded patellar tendons were compared to those of collagen fascicles from non-treated patellar tendons and those of stress-shielded bulk patellar tendons in the rabbit. Background. Effects of stress deprivation and stress enhancement on the mechanical properties of knee joint tendons and ligaments have been extensively studied in various animal models. However, the roles of such substructural components as collagen fascicles in the remodeling of tendons and ligaments have not been studied well. Method. Tensile and viscoelastic properties of collagen fascicles obtained from the rabbit patellar tendons which were completely stress-shielded for 1 to 3 weeks by a special method developed by the authors were determined using a micro tensile tester. Results. Stress shielding significantly decreased the tangent modulus, tensile strength, and strain at failure of collagen fascicles. However, these changes were much smaller than those observed in bulk tendons. The relaxation of stress-shielded collagen fascicles was greater than that of non-treated ones. Conclusions. Ground substance and mechanical interaction between collagen fascicles have important rules in the remodeling of tendons and ligaments.
  • Mechanical properties of collagen fascicles from the rabbit patellar tendon, E. Yamamoto, K. Hayashi, Journal of Biomechanical Engineering, Journal of Biomechanical Engineering, 121(1), 124 - 131, 1999 , Refereed
    Summary:Tensile and viscoelastic properties of collagen fascicles of approximately 300 pm in diameter, which were obtained from rabbit patellar tendons, were studied using a newly designed micro-tensile tester. Their cross-sectional areas were determined with a video dimension analyzer combined with a CCD camera and a low magnification microscope. There were no statistically significant differences in tensile properties among the fascicles obtained from six medial-to-lateral locations of the patellar tendon. Tangent modulus, tensile strength, and strain at failure of the fascicles determined at about 1.5 percent/s strain rate were 216 ± 68 MPa, 17.2 ± 4.1 MPa, and 10.9 ± 1.6percent (mean ± S.D.), respectively. These properties were much different from those of bulk patellar tendons for example, the tensile strength and strain at failure of these fascicles were 42 percent and 179 percent of those of bulk tendons, respectively. Tangent modulus and tensile strength of collagen fascicles determined at 1 percent/s strain rate were 35 percent larger than those at 0.01 percent/s. The strain at failure was independent of strain rate. Relaxation tests showed that the reduction of stress was approximately 25 percent at 300 seconds. These stress relaxation behavior and strain rate effects of collagen fascicles differed greatly from those of bulk tendons. The differences in tensile and viscoelastic properties between fascicles and bulk tendons may be attributable to ground substances, mechanical interaction between fascicles, and the difference of crimp structure of collagen fibrils. © 1999 by ASME.

Conference Activities & Talks

  • Evaluation of dynamic viscoelastic properties of hairless mice, Katsuragi, M, Kageyama, K, Yamamoto, E, Sakai, T, The 13th International Symposium on Advanced Science and Technology in Experimental Mechanics,   2018 11 03
  • Adjustment of pull-out force due to the slit configuration in acetabular cup of artificial hip joint with a structure for preventing dislocation, Kawamura, Y, Imai, D, Tanifuji, Y, Ohmasa, M, Yamamoto, E, The 13th International Symposium on Advanced Science and Technology in Experimental Mechanics,   2018 11 03
  • Residual strength of cortical bone after creep loading at a high stress magnitude, Tanifuji, Y, Imai, D, Kawamura, Y, Yamamoto, E, The 13th International Symposium on Advanced Science and Technology in Experimental Mechanics,   2018 11 02
  • Mechanical and histological evaluation for skin tissues damaged by high intensity ultraviolet irradiation, Imai, D, Kawamura, Y, Tanifuji, Y, Takemori, K, Ito, H, Yamamoto, E, The 13th International Symposium on Advanced Science and Technology in Experimental Mechanics,   2018 11 02
  • External application of elastin has an inhibitory effect on the skin hypertrophy and hardening due to repetitive ultraviolet irradiation, Yamamoto, E, Imai, D, Takemori, K, Ito, H, The 8th World Congress of Biomechanics,   2018 07 10
  • Finite element analysis to determine the pull-out forces of the artificial hip joint with a structure for preventing the dislocation, Kawamura, Y, Yamamoto, E, The 8th World Congress of Biomechanics,   2018 07
  • Influence of elastin application on the mechanical properties of dorsal skins in hairless mice subjected to ultraviolet irradiation, Imai, D, Kawamura, Y, Takemori, K, Ito, H, Yamamoto, E, The 12th International Symposium on Advanced Science and Technology in Experimental Mechanics,   2017 11
  • Mechanical evaluation of pull-out forces of the artificial hip joint with a preventing structure from dislocation, Kawamura, Y, Imai, D, Ohmasa, M, Kobayashi, T, Matsufuji, Y, Saito, M, Uwa, Y, Washio, S, Yamamoto, E, The 12th International Symposium on Advanced Science and Technology in Experimental Mechanics,   2017 11
  • Effects of elastin components on the biomechanical and histomorphological properties of ultraviolet-irradiated skins in hairless mice, Yamamoto, E, Takemori, K, Ito, H, The Fifth Japan-Switzerland Workshop on Biomechanics,   2017 09
  • Changes in the structure and mechanical properties of bone tissues obtained from experimental animal models of lifestyle-related diseases, Yamamoto, E, Kawamura, Y, The 5th International Conference on Advances in Mechanical Engineering,   2017 08
  • Biomechanical properties of femora obtained from stroke-prone spontaneously hypertensive rats, Yamamoto, E, Takemori, K, Ito, H, The 17th Congress of the International Society of Biomechanics,   2017 07
  • Biomechanical contribution of elastin components to the extensibility of skin tissues, Yamamoto, E, Imai, D, Takemori, K, Ito, H, The International Conference on Computational and Experimental Engineering and Science 2017,   2017 06
  • AE characterization of microdamage in tendon under different loading condition, Matsuoka, F, Wakayama, S, Sakai, T, Yamamoto, E, The 23th International Acoustic Emission Symposium,   2016 12
  • Biomechanical analysis of the effects of trabecular bone on the stress distribution in the rat lower limb, Kawamura, Y, Nishimoto, M, Yamamoto, E, The 11th International Symposium on Advanced Science and Technology in Experimental Mechanics,   2016 11
  • Mechanical behavior of anisotropic bone tissues after overloading, Nishimoto, M, Kawamura, Y, Yamamoto, E, The 11th International Symposium on Advanced Science and Technology in Experimental Mechanics,   2016 11
  • Characterization of rupture process in rabbit patellar tendon under dynamic tensile load by acoustic emission technique, Matsuoka, F, Wakayama, S, Sakai, T, Yamamoto, E, he 6th International Conference on Mechanics of Biomaterials and Tissues,   2015 12
  • Biomechanical contribution of elastin to the healing of ultraviolet-irradiated skin in hairless mice, Yamamoto, E, Susaki, Y, Nishi, S, Takemori, K, Ito, H, The 6th International Conference on Mechanics of Biomaterials and Tissues,   2015 12
  • Changes in the biomechanical properties of cortical bone in stroke-prone spontaneously hypertensive rats due to the exposure undernutrition during the period of pregnancy, Yamamoto, E, Takeda, I, Takemori, K, Ito, H, he International Conference on Advanced Technology in Experimental Mechanics 2015,   2015 10
  • Biomechanical and histological changes in ultraviolet-irradiated skin tissues due to the external application of elastin, Yamamoto, E, Susaki, Y, Nishi, S, Takemori, K, Ito, H, The 8th Asian-Pacific Conference on Biomechanics,   2015 09
  • Detection of microdamage in rabbit patellar tendon under impact tensile load by acoustic emission, Matsuoka, F, Wakayama, S, Sakai, T, Yamamoto, E, The 8th Asian-Pacific Conference on Biomechanics,   2015 09
  • Evaluation on the effect of lap-strake perforated amorphous calcium phosphate sheets on the sealing of dentinal tubules, IDO YUKI, ISAI ARATA, YAMAMOTO EI, KATO NOBUHIRO, NISHIKAWA HIROAKI, YASUO KENZO, HASHIMOTO YOSHIYA, YOSHIKAWA KAZUSHI, YAMAMOTO KAZUYO, HONTSU SHIGEKI, 日本歯科理工学会誌,   2015 03 25
  • Evaluation of the dentin permeability inhibition effect by lap-strake method of the amorphous calcium phosphate sheet, ISAI ARATA, YAMAMOTO EI, KATO NOBUHIRO, NISHIKAWA HIROAKI, YASUO KENZO, HASHIMOTO YOSHIYA, YOSHIKAWA KAZUSHI, YAMAMOTO KAZUYO, HONTSU SHIGEKI, 日本歯科理工学会誌,   2014 09 20
  • Preparation and evaluation of ultra thin potassium-doped hydroxyapatite sheet, HATOKO YUKA, YAMAMOTO EI, KATO NOBUHIRO, NISHIKAWA HIROAKI, YOSHIKAWA KAZUSHI, FURUZONO TSUTOMU, YAMAMOTO KAZUYO, HONTSU SHIGEKI, 日本歯科理工学会誌,   2014 09 20
  • Biomechanical role of elastin in skin tissues, Yamamoto, E, Takemori, K, Ito, H, The Fourth Japan-Switzerland Workshop on Biomechanics,   2014 09
  • Examination of dentine restoration using the Er:YAG laser ablation method (Part 1), HONTSU SHIGEKI, YAMAMOTO EI, KATO NOBUHIRO, NISHIKAWA HIROAKI, HASHIMOTO YOSHIYA, YOSHIKAWA KAZUSHI, YAMAMOTO KAZUYO, 日本歯科理工学会誌,   2014 03 25
  • Formation of the artificial enamel on dentin using the ultrathin apatite sheet, HONTSU SHIGEKI, YOSHIKAWA KAZUSHI, ISAI ARATA, YAMAMOTO EI, KATO NOBUHIRO, NISHIKAWA HIROAKI, KUSUNOKI MASANOBU, HASHIMOTO YOSHIYA, YAMAMOTO KAZUYO, 日本歯科理工学会誌,   2012 09 25
  • Effects of Elastin Peptide from Bonito Bulbus Arteriosus on Vascular Structure and Function in Spontaneously Hypertensive Rat, Takemori, K, Yamamoto, E, Ito, H, The 15th International SHR Symposium,   2012 09 , 15th International SHR Symposium
  • Biomechanical characterization of the knee joint in an experimental model of osteoarthritis, Yamamoto, E, Fujita, I, Sakakibara, A, Okumura, T, International Symposium on Advanced Fluid/Solid Science and Technology in Experimental Mechanics,   2006 09 , International Symposium on Advanced Fluid/Solid Science and Technology in Experimental Mechanics
  • Effects of cyclic loading on the residual strength of cortical bone: implications for fatigue fracture, Yamamoto, E, Mita, A, 5th World Congress of Biomechanics,   2006 07 , 5th World Congress of Biomechanics
  • Intermittent vs. continuous creep loading of trabecular bone, 52th Annual Meeting of the Orthopaedic Research Society,   2006 03 , 52th Annual Meeting of the Orthopaedic Research Society
  • Biomechanical evaluation for knee osteoarthritis in rats,   2006 03
  • Multicyclic creep tests of human vertebral trabecular bone,   2006 01
  • Bimechanical response of collagen fascicles to stress during culture, The Second Japan-Switzerland Workshop on Biomechanics,   2005 09 , The Second Japan-Switzerland Workshop on Biomechanics
  • Effects of immobilization on in vivo strains in the rabbit femur: Long-time measurement with a telemetric system, American Society of Mechanical Engineers, 2005 Summer Bioengineering Conference,   2005 06 , American Society of Mechanical Engineers, 2005 Summer Bioengineering Conference
  • Human vertebral trabecular bone exhibits non-linear viscoelastic behavior at low loading levels: Implications for vertebral fracture etiology, 51th Annual Meeting of the Orthopaedic Research Society,   2005 03 , 51th Annual Meeting of the Orthopaedic Research Society
  • A comparative study on the effects of static and cyclic loading on the creep strain of human vertebral trabecular bone,   2005 01
  • Fatigie behavior of human vertebral trabecular bone after overloading,   2004 11
  • Biomechanical properties of cortical bone in rats whose growth hormone gene expression was suppressed by antisense RNA transgene,   2003 06
  • Relation between the microhardness and physical characteristics of femur in transgenic rats,   2003 03
  • Effects of cyclic load on the residual strength of the rabbit femur,   2003 01
  • Effects of immobilization on in vivo strains in the rabbit femur,   2003 01
  • Measurements of the biomechanical properties of cortical bone in transgenic rats,   2003 01
  • The effect of overloading on the patellar tendon that underwent segmental resection of its one-third portion,   2002 08
  • Long-time measurement of in vivo bone strains with a newly designed telemetric system,   2002 08
  • Development of an apparatus for the long time measurements of in vivo bone loading conditions,   2002 03
  • Mechanical properties of tissue regenerated in the central third defect in the rabbit patellar tendon,   2001 10
  • Temporal change in the mechanical properties of callus tissues formed in tibial defects in the rabbit,   2001 10
  • Changes of the mechanical properties of the unresected and the regenerated tissue in the patellar tendon after resecting the central portion, 4th Combined Meeting of the Orthopaedic Research Societies of the U.S.A., Canada, Europe, and Japan (Rhodes),   2001 06 , 4th Combined Meeting of the Orthopaedic Research Societies of the U.S.A., Canada, Europe, and Japan (Rhodes)
  • Observation of the microcrack in the cyclically loaded rabbit femur,   2001 03
  • Effects of stress shielding on the mechanical properties of healing tissue in the patellar tendon after removal of its central portion,   2001 03
  • Atomic force microscopic measurement of the local stiffness in the cyclically loaded rabbit femur,   2001 01

Research Grants & Projects

  • Micromechanics of Bone Fatigue
  • Study on the Mechanical Properties and Remodeling of Living Tissue.