Researcher Database

Ikuya Nishimura
Faculty of Information Science and Technology Bioengineering and Bioinformatics Bioengineering
Assistant Professor

Researcher Profile and Settings

Affiliation

  • Faculty of Information Science and Technology Bioengineering and Bioinformatics Bioengineering

Job Title

  • Assistant Professor

URL

J-Global ID

Research Interests

  • 人工関節   潤滑   表面パターン   反応性スパッタ蒸着   開発機械弁   流れの可視化   血液ポンプ   潤滑液の供給   弁機能特性   ジュラルミン   数値流体解析   ル-トプレ-ニング   磁気シール   パターン模様   真球度   加速耐久試験機   スメラ層   カップの摩耗   アルミナスパッタ蒸着   動圧軸受   歯根面粗さ   人工心臓   プラ-ク   心臓代用弁   磁性流体シール   摩擦・摩耗現象   溶血量   機能性表面構造   α角   刃先角   

Research Areas

  • Life sciences / Biomaterials
  • Life sciences / Biomedical engineering

Academic & Professional Experience

  • 2004 - 2005 北海道大学 大学院・情報科学研究科 助手

Research Activities

Published Papers

  • Masaru Higa, Hiromasa Tanino, Ikuya Nishimura, Yoshinori Mitamura, Takeo Matsuno, Hiroshi Ito
    JOURNAL OF ARTIFICIAL ORGANS 18 (1) 79 - 85 1434-7229 2015/03 [Refereed][Not invited]
     
    This study proposes novel optimized stem geometry with low stress values in the cement using a finite element (FE) analysis combined with an optimization procedure and experimental measurements of cement stress in vitro. We first optimized an existing stem geometry using a three-dimensional FE analysis combined with a shape optimization technique. One of the most important factors in the cemented stem design is to reduce stress in the cement. Hence, in the optimization study, we minimized the largest tensile principal stress in the cement mantle under a physiological loading condition by changing the stem geometry. As the next step, the optimized stem and the existing stem were manufactured to validate the usefulness of the numerical models and the results of the optimization in vitro. In the experimental study, strain gauges were embedded in the cement mantle to measure the strain in the cement mantle adjacent to the stems. The overall trend of the experimental study was in good agreement with the results of the numerical study, and we were able to reduce the largest stress by more than 50 % in both shape optimization and strain gauge measurements. Thus, we could validate the usefulness of the numerical models and the results of the optimization using the experimental models. The optimization employed in this study is a useful approach for developing new stem designs.
  • Ikuya Nishimura, S. Ichikawa, M. Mikami, H. Ishitoya, T. Motomura, M. Kawamura, J. Linneweber, J. Glueck, T. Shinohara, Y. Nose
    BIO-MEDICAL MATERIALS AND ENGINEERING 23 (1-2) 49 - 55 0959-2989 2013 [Refereed][Not invited]
     
    The Gyro centrifugal pump developed as a totally implantable artificial heart was designed with a free impeller, in which the rotational shaft (male bearing) of the impeller was completely separated from the female bearing. For this type of pump, it is very important to keep the proper magnet balance (impeller-magnet and actuator-magnet) in order to prevent thrombus formation and/or bearing wear. When the magnet balance is not proper, the impeller is jerked down into the bottom bearing. On the other hand, if magnet balance is proper, the impeller lifted off the bottom of the pump housing within a certain range of pumping conditions. In this study, this floating phenomenon was investigated in detail. The floating phenomenon was proved by observation of the impeller behavior using a transparent acrylic pump. The impeller floating phenomenon was mapped on a pump performance curve. The impeller floating phenomenon is affected by the magnet-magnet coupling distance and rotational speed of the impeller. In order to keep the proper magnet balance and to maintain the impeller floating phenomenon at the driving condition of right and left pump, the magnet-magnet coupling distance was altered by a spacer which was installed between the pump and actuator. It became clear that the same pump could handle different conditions (right and left ventricular assist), by just changing the thickness of the spacer. When magnet balance is proper, the floating impeller phenomenon occurs automatically in response to the impeller rev. It is called "the dynamic RPM suspension".
  • Toshimasa Ishida, Ikuya Nishimura, Hiromasa Tanino, Masaru Higa, Hiroshi Ito, Yoshinori Mitamura
    ARTIFICIAL ORGANS 35 (4) 404 - 410 0160-564X 2011/04 [Refereed][Not invited]
     
    There are many designs of the femoral stem of a cemented total hip arthroplasty, and mechanical failure of the stem is caused by several factors related to the cement, such as failure of the cement. Optimization of the shape of the stem, especially multiobjective optimization, is required to solve these design problems because a cement fracture is caused by multiple factors. The objective of this study was to determine a stem geometry considering multiple factors at the same time. A three-dimensional finite element model of the proximal femur was developed from a composite femur. A total of four objective functions-two objective functions, the largest maximum principal stress of proximal and distal sections in the cement mantle, for each of the two boundary conditions, walking and stair climbing-were used. The neighborhood cultivation genetic algorithm was introduced to minimize these objective functions. The results showed that the geometry that leads to a decrease in the proximal cement stress and the geometry that leads to a decrease in the distal cement stress were not the same. However, the results of the walking and the stair climbing conditions matched. Five dominant stem designs were considered to be the Pareto solution, and one design was identified as the "better design" for all objective functions. It was shown that multiobjective optimization using a genetic algorithm may be used for optimizing the shape of the femoral stem in order to avoid cement fracture.
  • Yoshinori Mitamura, Sayaka Takahashi, Shuichi Amari, Eiji Okamoto, Shun Murabayashi, Ikuya Nishimura
    JOURNAL OF ARTIFICIAL ORGANS 14 (1) 23 - 30 1434-7229 2011/03 [Refereed][Not invited]
     
    A magnetic fluid (MF) seal enables mechanical contact-free rotation of the shaft and hence has excellent durability. The performance of an MF seal, however, has been reported to decrease in liquids. We developed an MF seal that has a "shield" mechanism, and a new MF with a higher magnetization of 47.9 kA/m. The sealing performance of the MF seal installed in a rotary blood pump was studied. Three types of MF seals were used. Seal A was a conventional seal without a shield. Seal B had the same structure as that of Seal A, but the seal was installed at 1 mm below liquid level. Seal C was a seal with a shield and the MF was set at 1 mm below liquid level. Seal A failed after 6 and 11 days. Seal B showed better results (20 and 73 days). Seal C showed long-term durability (217 and 275 days). The reason for different results in different seal structures was considered to be different flow conditions near the magnetic fluid. Fluid dynamics near the MF in the pump were analyzed using computational fluid dynamics (CFD) software. We have developed an MF seal with a shield that works in liquid for > 275 days. The MF seal is promising as a shaft seal for rotary blood pumps.
  • Yoshinori Mitamura, Sayaka Takahashi, Shuichi Amari, Eiji Okamoto, Shun Murabayashi, Ikuya Nishimura
    12TH INTERNATIONAL CONFERENCE ON MAGNETIC FLUIDS ICMF12 9 229 - 233 1875-3892 2010 [Refereed][Not invited]
     
    A magnetic fluid (MF) seal enables mechanical contact-free rotation of the shaft and hence has excellent durability. The mechanism and a new MF with a higher magnetization of 47.9 kA/m. The sealing performance of the MF seal installed in a rotary blood pump was studied. The seal was perfect against a pressure of 150 mmHg in a continuous flow of 4.0 L/min for 275 days and against a pressure of 175 mmHg in a continuous flow of 3.9 L/min for 217 days. We have developed a MF seal that works in liquid against pressure mostly used clinically. The magnetic fluid seal is promising as a shaft seal for rotary blood pumps. (C) 2010 Published by Elsevier Ltd
  • Yoshinori Mitamura, Sayaka Takahashi, Kentaro Kano, Eiji Okamoto, Shun Murabayashi, Ikuya Nishimura, Taka-aki Higuchi
    ARTIFICIAL ORGANS 33 (9) 770 - 773 0160-564X 2009/09 [Refereed][Not invited]
     
    A magnetic fluid (MF) for a rotary blood pump seal enables mechanical contact-free rotation of the shaft and, hence, has excellent durability. The performance of a MF seal, however, has been reported to decrease in liquids. We have developed a MF seal that has a "shield" mechanism and a new MF with a higher magnetization of 47.9 kA/m. The sealing performance of the MF seal installed in a rotary blood pump was studied. Under the condition of continuous flow, the MF seal remained in perfect condition against a pressure of 298 mm Hg (pump flow rate: 3.96 L/min). The seal was also perfect against a pressure of 170 mm Hg in a continuous flow of 3.9 L/min for 275 days. We have developed a MF seal that works in liquid against clinically used pressures. The MF seal is promising as a shaft seal for rotary blood pumps.
  • ABE Leona, NISHIMURA Ikuya, IZUMISAWA Yasuharu
    The journal of veterinary medical science 社団法人日本獣医学会 70 (11) 1191 - 1198 0916-7250 2008/11/25 [Not refereed][Not invited]
     
    Orthopedic fixation of irreversibly damaged joints entails the use of artificial joints. Porous coated prostheses require no bone cement, but coating to the implant is susceptible to avulsion from the surface. The purpose of this pilot study was to test an improved non-coated grit blast titanium implant having a direct surface roughness of 33.4μm with a wide contrast of 251.6μm between the valleys and peaks, i.e., about ten times rougher than conventional grit blast, and designed with bumpy, acutely articulated depressions. Fifty-six implants (28 grit blast, 28 smooth) were tested in the fe...
  • KANO Kentaro, TAKAHASHI Sayaka, AMARI Syuichi, NISHIMURA Ikuya, MURABAYASHI Shun, OKAMOTO Eiji, MITAMURA Yoshinori
    電気学会研究会資料. LD, リニアドライブ研究会 2008 (66) 25 - 30 2008/11/21 [Not refereed][Not invited]
  • ISHIDA Toshimasa, NISHIMURA Ikuya, MITAMURA Yoshinori, TANINO Hiromasa, ITO Hiroshi, MATSUNO Takeo
    Transactions of the Japanese Society for Medical and Biological Engineering : BME 社団法人日本生体医工学会 46 (2) 226 - 231 1347-443X 2008/04/10 [Not refereed][Not invited]
     
    Mechanical failure of the cemented hip stem is mainly caused by several cement mantle problems such as cement fracture. Geometries of the cement mantle and the stem are important factors of failure risks. Shape optimization, especially multi-objective optimization, is required to solve these design problems, because the cement fracture is caused by multiple factors. In this study the stem design was optimized using a genetic algorithm suitable for multi-objective optimization. A three-dimensional finite element model of the proximal femur was developed. Two objective functions, the largest ...
  • Mechanically Non-contact Axial Flow Blood Pump
    Y.MITAMURA, K.KIDO, T.YANO, D.SAKOTA, R.YOZU, E.OKAMOTO, S.MURABAYASHI, I.NISHIMURA
    Biocybernetics and Biomedical Engineering 27 139 - 146 2007 [Refereed][Not invited]
  • NISHIMURA Ikuya, ISHIDA Toshimasa, MURABAYASHI Shun, MITAMURA Yoshinori, NAKAMURA Toshiki, ITO Hiroshi, MATSUNO Takeo, HIGA Masaru, HASEI Minoru, KURAMOTO Kouichi
    Transactions of Japanese Society for Medical and Biological Engineering 社団法人日本生体医工学会 44 (1) 77 - 84 1347-443X 2006/03/10 [Not refereed][Not invited]
     
    As the result of developments in computer technology in recent years, the calculation, simulation and analysis of the stress environment for the artificial hip prosthesis and the femur have been made possible. In order to perform an exact calculation, three-dimensional modeling with the hip prosthesis and femur is required. The modeling of a femur is done by reconstructing the femoral outline data from CT images using three-dimensional CAD. The outline extraction work is performed by the experience and subjectivity of the operator, and the reliability of the data and working efficiency is low. In this paper, algorithms that extract the femur outline from CT images automatically are proposed. A Snake-based outline extraction algorithm is used. Although this method is capable of extracting the cortical bone outline of femoral diaphysis with sufficient accuracy, there was high incorrect detection at the trochanter. The shape of the trochanter is complicated, and it is difficult to process using a simple algorithm. Therefore, we proposed a method of visually expressing the possibility that a certain pixel in an image is high or low. This method is capable of detecting portions of images with high differentiations in value (contrast changes rapidly). It can also detect outlines at the diaphysis and trochanter. The problems of this technique are that the pixels judged as possibly being a part of the outline appear in the portion that is not a true outline, and that the pixels judged as possibly being on the outline may not be continuous. When each method was used independently, neither was capable of performing a positive outline extraction. However, an outline sampling sufficiently high certainty was achieved when using the two methods simultaneously.
  • Bonding strength evaluation of cementless implant by grit blasting
    Yosuke Kozaki, Ikuya Nishimura, Yoshinori Mitamura, Shun Murabayashi, Yasuharu Izumisawa, Kouichi Kuramoto
    Proceeding of World Congress on Medical Physics and Biomedical Engineering 14 3124 - 3126 2006 [Refereed][Not invited]
  • H. Tanino, H. Ito, M. Higa, N. Omizu, I. Nishimura, K. Matsuda, Y. Mitamura, T. Matsuno
    JOURNAL OF BIOMECHANICS 39 (10) 1948 - 1953 0021-9290 2006 [Refereed][Not invited]
     
    The number of stem designs for total hip arthroplasty is increasing, and occasionally design changes have yielded unexpected clinical results. At present, we are not able to clearly identify which parameter of the stem is most important, and the optimum value of many parameters. The goals of this study were to identify which parameter is most important, to understand the effect of design change, and to find the optimum stem shape. For this purpose, we used adaptive p-method together with three-dimensional computer-aided design software program for the design sensitivity analysis (DSA) and shape optimization of the stem. The results suggested that increasing the lateral and medial width of the distal cross-section together with decreasing the medial-lateral width and the medial radius of the distal cross-section from the default value would lead to a decrease in the largest maximum principal stress of the distal cement. The medial width of middle cross-section, however, was not so simple. The result of DSA suggested that decreasing this parameter from the default value decreased the stress in the distal cement, but the optimum shape was obtained by increasing this parameter. The method used in this study will assist our engineers and surgeons in the process of modifying and optimizing the stem design. (c) 2005 Elsevier Ltd. All rights reserved.
  • ISHIDA Toshimasa, YAGIHASHI Kouta, NISHIMURA Ikuya, TANINO Hiromasa, ITO Hiroshi, MATSUNO Takeo, MITAMURA Yoshinori, HARMAN M. K, BANKS S. A, MODGE W. A
    日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 26 (0) 233 - 237 1340-9018 2005/10/01 [Not refereed][Not invited]
  • YANO Tetsuya, MITOH Ayumi, MITAMURA Yoshinori, NISHIMURA Ikuya, MURABAYASHI Shun, YOZU Ryohei
    Transactions of the Japanese Society for Medical and Biological Engineering : BME 社団法人日本生体医工学会 43 (1) 85 - 92 1347-443X 2005/03/10 [Not refereed][Not invited]
     
    Hemolysis is a major factor for developing successful blood pumps. A major cause of hemolysis is the mechanical stress acting on the corpuscles passing through the pump. The empirical formula, which expresses the relationship of the shear stress, exposure time, and hemoglobin release serves as a basic model for the estimation of blood damage. We have conducted computational fluid dynamics (CFD) -based assessment for the hemolysis within the blood pump using one of the above mathematical models. Assuming that the red blood cells pass along the streamlines, a blood damage index was calculated...
  • TANINO Yukinori, HIGA Masaru, NISHIMURA Ikuya, ISHIDA Toshimasa, OHATA Noboru, MITAMURA Yoshinori
    日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 25 (0) 223 - 228 1340-9018 2004/11/01 [Not refereed][Not invited]
  • 西村 生哉, 清水 亮太, 中村 聡喜, 松野 丈夫, 三田村 好矩
    年次大会講演論文集 : JSME annual meeting 一般社団法人日本機械学会 2004 (5) 129 - 130 2004/09/04 [Not refereed][Not invited]
     
    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.
  • YAGIHASHI Kouta, MITAMURA Yoshinori, NISHIMURA Ikuya, ISHIDA Toshimasa, ITO Hiroshi, TANINO Hiromasa, NAKAMURA Toshiki, MATSUNO Takeo
    IEICE technical report. ME and bio cybernetics 一般社団法人電子情報通信学会 104 (129) 21 - 23 0913-5685 2004/06/11 [Not refereed][Not invited]
     
    Prosthetic impingement after THA is to different for the angle and shape of the implant. Purpose of this study is examine the range of motion(ROM) on a computer when angle and shape of the implant are changed. The angle was measured in the flexion, extension, adduction direction by every 0.1 degrees. All 324 patterns of the above model were measured. As a result hen the radius of neck and the neck shaft angle decrease, the increase of the ROM expected.
  • SENO Takahiro, IZUMISAWA Yasuharu, NISHIMURA Ikuya, MAEHARA Seiya, KUSHIRO Tokiko, UMAR Mohammed Ahmed, WAKAIKI Shinsuke, YAMASHITA Kazuto, KOTANI Tadao
    The journal of veterinary medical science 社団法人日本獣医学会 66 (3) 315 - 318 0916-7250 2004/03/25 [Not refereed][Not invited]
     
    Screw and laser (SL) column by making screw threads and forming small holes using laser irradiation on the base metal and conventional beads coating (BC) columns were embedded into the shaft of canine femurs, and compared the implant fixation to the host bone. The interfacial strength in SL columns was almost equivalent as BC columns, and bone-column contact rate was higher than BC columns significantly at twelve weeks after implantation. The newly devised SL surface had almost equivalent bone fixation strength comparable to the conventional BC surface. Also, this surface should provide a u...
  • SENO Takahiro, IZUMISAWA Yasuharu, NISHIMURA Ikuya, MAEHARA Seiya, YOKOYAMA Tokiko, YAMASHITA Kazuto, KOTANI Tadao
    The journal of veterinary medical science 社団法人日本獣医学会 65 (3) s・viii - s・ix, 419-422 0916-7250 2003/03/25 [Not refereed][Not invited]
     
    Titanium columns (Ti-6A1-4V) were treated with arc-deposition to roughen the surface enough to anchor the bone, and then coated with hydroxyapatite (HA) at a thickness of 5 μm by the sputtering technique. Columns were implanted into dog femurs, and fixation of columns to bone due to bone-ingrowth was assessed histologically and with the push-out test. The HA-coated columns were inserted in the shafts of the right femurs of 2 dogs. As a control, columns that were only arc-deposited (non-coated columns) were inserted into the left femurs. The interfacial strength was higher for the HA-coated ...
  • HIGA Masaru, NISHIMURA Ikuya, TANINO Hiromasa, ITOH Hiroshi, MATSUNO Takeo, MITAMURA Yoshinori
    TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A 一般社団法人日本機械学会 69 (679) 689 - 694 0387-5008 2003/03/25 [Not refereed][Not invited]
     
    When cemented hip replacement implants are developed using a finite element method (FEM), the validation of the inplants comparing with experimental tests and clinical survival data should be required. As the first step, the optimum shape of the femoral component of total hip arthroplasty (THA) was designed to minimize the stress peak in the cement mantle that is the primal cause for fixation failure. In the next step, the strain in the cement mantle surrounding the cemented femoral components of THA was measured using strain gauges embedded within the cement mantle adjacent to the developed femoral stem to validate the optimization results of FEM. As a result of this study, optimum shape of femoral component was developed and the FEM results were validated by strain gauge experiments.
  • HIGA Masaru, NISHIMURA Ikuya, TANINO Hiromasa, ITOH Hiroshi, ISHIDA Toshimasa, MATSUNO Takeo, MITAMURA Yoshinori
    日本臨床バイオメカニクス学会誌 = Proceedings of ... Annual Meeting of Japanese Society for Clinical Biomechanics and Related Research 23 (0) 167 - 172 1340-9018 2002/11/01 [Not refereed][Not invited]
  • The outline sampling strategies for the femoral CT images
    I. Nishimura, T. Ishida, S. Murabayashi, Y. Mitamura, T. Nakamura, H. Ito, T. Matsuno, M. Higa, M. Hasei, K. Kuramoto
    Proceeding of World Congress on Medical Physics and Biomedical Engineering 14 2441 - 2444 [Refereed][Not invited]

Books etc

  • 臨床工学技士のための機械工学
    西村生哉 (Single work)
    2013/01
  • 臨床工学技士のための生体物性
    村林 俊 (Supervisor)
    2012/06
  • 超精密生産技術大系、第4巻 第6編
    (Joint work第2章 第4節、人工骨)
    株式会社フジ・テクノシステム 1996/02

MISC

  • Ishida Toshimasa, Nishimura Ikuya, Tanino Hiromasa, Ito Hiroshi, Matsuno Takeo, Mitamura Yoshinori  年次大会講演論文集 : JSME annual meeting  2005-  (5)  207  -208  2005/09/18  [Not refereed][Not invited]
     
    Total hip arthroplasty (THA) is mainly used for the patients, who are affected with rheumatoid arthritis, coxarthrosis, and so on. The long-term success of total hip arthroplasty depends on the chance of acrylic cement failure and interface disruption. The purpose of this study is to minimize the risks of cement failure by using optimization. A generic three-dimensional FEM model of the proximal femur containing a cemented femoral stem of a total hip arthroplasty was developed. The design parameters are defined on cross section of stem. The design objective was to minimize several principal...
  • Higa Masaru, Nishimura Ikuya, Maeda Fuyuhiko, Seno Takahiro, Izumisawa Yasuharu, Mitakura Yoshinori  年次大会講演論文集 : JSME annual meeting  2004-  (5)  127  -128  2004/09/04  [Not refereed][Not invited]
     
    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...
  • YANO Tetsuya, Mitoh Ayumi, SEKINE Kazumitsu, MITAMURA Yoshinori, NISHIMURA Ikuya, MURABAYASHI Shun, YOZU Ryohei  年次大会講演論文集 : JSME annual meeting  2004-  (5)  189  -190  2004/09/04  [Not refereed][Not invited]
     
    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 ...
  • 石田 敏真, 西村 生哉, 比嘉 昌, 谷野 弘昌, 伊藤 浩, 松野 丈夫, 三田村 好矩  生体医工学 : 日本エム・イー学会誌  42-  (2)  2004/06/10  [Not refereed][Not invited]
  • Sekine Kazumitsu, Mitamura Yoshinori, Murabayashi Shun, Nishimura Ikuya, Yozu Ryohei  年次大会講演論文集 : JSME annual meeting  2003-  (5)  95  -96  2003/08/05  [Not refereed][Not invited]
     
    A magnetic fluid (MF) seal was specially designed for use in an axial-flow blood pump. There are some potential problems to be solved for the use as a shaft seal for blood pumps. Experimental and theoretical sealing pressures, a long-term performance of the MF seal and biocompatibility of MF were studied. The sealing pressure was about 200mmHg in blood in the experiments. The theoretical sealing pressure was over 300mmHg with the use of high magnetization MF. The results of long-term performance tests showed that the durability of the seal was over 1 year. The results of cytotoxicity tests ...
  • SHIMIZU Ryota, NISHIMURA Ikuya, NAKAMURA Toshiki, MATSUNO Takeo, MITAMURA Yoshinori  年次大会講演論文集 : JSME annual meeting  2003-  (7)  141  -142  2003/08/05  [Not refereed][Not invited]
     
    A high prevalence of thigh pain has been reported after cementless total hip arthroplasty. But it is still unknown about the in-depth mechanism. To study the relevance between the occurrence of thigh pain and the stress in femur, we made animal experiment and actually put pressure on rabbit thigh from the medullary cavity using balloon catheter. The results of the experiments are reported here.
  • 今野 慎介, 村林 俊, 西村 生哉, 片山 茂, 三田村 好矩, 米川 元樹, 岡本 英治  生体医工学 : 日本エム・イー学会誌  41-  (1)  2003/03/10  [Not refereed][Not invited]
  • Ishida Toshimasa, Nishimura Ikuya, Higa Masaru, Mitamura Yoshinori  バイオエンジニアリング講演会講演論文集  2003-  (15)  409  -410  2003/01/20  [Not refereed][Not invited]
  • Ishida Toshimasa, Nishimura Ikuya, Higa Masaru, Mitamura Yoshinori  年次大会講演論文集 : JSME annual meeting  2002-  (6)  53  -54  2002/09/20  [Not refereed][Not invited]
     
    The long-term success of total hip arthroplasty (THA) depends on the chance of acrylic cement failure and interface disruption. This chance can be diminished by an optimal long-transfer mechanism, whereby stress concentrations are avoided. Implant design is decisive for success or failure. This paper introduces an optimum design of the hip prosthesis. A generic three-dimensional FEM model of the proximal femur containing a cemented femoral stem of a total hip arthroplasty was developed. The design objective was to minimize the largest maximum principal stress in the cement. To verify validi...
  • HIGA Masaru, NISHIMURA Ikuya, TANINO Hiromasa, ITOH Hiroshi, MATSUNO Takeo, MITAMURA Yoshinori  Journal of the Japan Society for Precision Engineering  68-  (7)  948  -952  2002/07/05  [Not refereed][Not invited]
     
    The present paper introduces an optimum design of the hip prosthesis and a method for shape optimization which minimizes the stress concentration within the cement mantle. A gradient projection method of numerical optimization and a p-version three-dimensional FEM of stress analysis were employed. A generic three-dimensional FEM model of the proximal femur containing a cemented fomoral stem of a total hip arthroplasty was developed. The three types of analysis was then performed in this study. First, stastic stress analysis measuring the stress in the bone cement was performed. The generic model was then valified parametrically by changing the each parameters individually that compose the stem geometry measureing the stress occuring within the cement mantle concurrently. As it is called design sensitivity analysis was performed. Finally, optimal stem shape was desigend using shape optimization. The design objective was to minimize the largest maximum principal stress in the cement. The results of shape optimization showed considerable reduction in stress concentration within the cement mantle compared to the starting design that were used. Moreover, the optimal stem shape obtained in this study showed unique geometry differ from the standard trend that has been believed to be better. The results of this study has shown to be attractive for evaluating stem design and develop the optimal new stem shape.
  • SATOH Shunsuke, MITAMURA Yoshinori, HIRAYAMA Yasushi, YUHTA Toshio, NISHIMURA Ikuya  IEICE technical report. ME and bio cybernetics  102-  (137)  9  -12  2002/06/14  [Not refereed][Not invited]
     
    This study was aimed at developing a method for measuring dental color using a digital image. The teeth of subjects, shade guides, and standard color samples were photographed with a digital camera under different lighting conditions. The RGB values of them were measured from the digital images. The values were changed into the Munsell values and the CIEL^*a^*b^* values. The calculated values were compared with dentist's diagnostic results, and dental chroma meter. Repeatability under the same condition was evaluated. The results indicated that dental color measured by digital images.
  • 瀬野 貴弘, 泉澤 康晴, 川村 祐介, 西村 生哉, 伊藤 浩, 大水 伸幸, 山下 和人, 小谷 忠生  獣医麻酔外科学雑誌 = Japanese journal of veterinary anesthesia & surgery  33-  (0)  2002/06/10  [Not refereed][Not invited]
  • 西村 生哉, 大水 信幸, 清水 亮太, 三田村 好矩  精密工学会大会学術講演会講演論文集  2002-  (1)  2002/03/01  [Not refereed][Not invited]
  • Matsuda Kazuhiro, Nisimura Ikuya, Tanino Hiromasa, Higa Masaru, Mitamura Yosinori  年次大会講演論文集 : JSME annual meeting  0-  (1)  79  -80  2001/08/22  [Not refereed][Not invited]
     
    Loosening of cemented femoral hip stems could be initiated by failure of the cement mantle due to high cement stress. This report describes static analysis of stress in the bone cement mantle, Design Sensitivity Analysis (DSA), and the three dimensional shape optimization of cemented femoral hip stems. This study analyzed stresses in the cement mantle, using a three-dimensional p-adaptive finite element method based on 3D CAD model. The p-methods and 3D CAD based model made an exact modeling possible. The results of the design optimization showed considerable reduction in stress concentrati...
  • Matsuno Takeo  Asahikawa Medical College research bulletin  2-  (1)  30  -35  2001/06/30  [Not refereed][Not invited]
     
    出版社版人工股関節置換術は末期股関節症患者に対して疼痛の軽減や可動域の回復を目的として行われる.以前は術後15年で,その約半数に弛みが生じるとされていたが,工学的技術及び手術手技的技術の改良で現在では術後15年における弛み率は5%以下になっている.しかし依然として人工股関節の経年的弛みは避けることの出来ない合併症であることも事実である.人工股関節弛みの最も大きな要因と考えられているのは関節摺動面において発生するポリエチレン摩耗粉である.将来的にポリエチレン摩耗粉の発生を減少(或いは防止)させることが可能となれば,一生弛むことのない人工股関節も夢ではない
  • Matuda Kazuhiro, Nisimura Ikuya, Tanino Hiromasa, Higa Masaru, Mitamura Yosinori  IEICE technical report. ME and bio cybernetics  101-  (130)  9  -14  2001/06/15  [Not refereed][Not invited]
     
    Loosening of cemented femoral hip stems could be initiated by failure of the cement mantle due to high cement stress. This report describes the three dimensional shape optimization of cemented femoral hip stems. Finite elements method (FEM) was combined with an optimization procedure to minimize stresses in the cement mantle adjacent to cemented femoral hip stem. We selected the p methods of analysis. The p-adaptive methods allows for greater shape changes without sacrificing the accuracy of the analysis. The results of the design optimization showed considerable reduction in stress concent...
  • HIGA Masaru, NISHIMURA Ikuya, MATSUDA Kazuhiro, TANINO Hiromasa, OMIZU Nobuyuki, MITAMURA Yoshinori  バイオエンジニアリング講演会講演論文集  2001-  (13)  154  -155  2001/01/15  [Not refereed][Not invited]
  • NISHIMURA Ikuya, HIGA Masaru, YUHTA Toshio, ITO Hiroshi, TANINO Hiromasa, OOMIZU Nobuyuki, MURABAYASHI Shun, MITAMURA Yoshinori  Journal of the Japan Society for Precision Engineering  66-  (10)  1594  -1598  2000/10/05  [Not refereed][Not invited]
     
    New surface structure with regular patterning for the frictional surfaces of the artificial joints was designed to improve the wear problems. The lubrication properties for the cup ( ultrahigh molecular weight polyethylene, UHMWPE) vs. ball ( Co-Cr alloy) were studied to evaluate the wear and surface roughness. The surface structure is the dents pattern which has diameter of 0.5mm, pitch of 1.2mm. In this study, such surface patterns were applied to artificial hip joints, and the effects of regular patterning on the frictional surface were investigated by using a joint simulator. The amount of wear of the cup that was in contact with the patterned head was only half that of the cup that was in contact with the non-patterned head, and the surface roughness of the cup with a non-patterned head was three-times greater than that of the cup with a patterned head. These results demonstrates that the lubrication properties can be improved by patterning of the frictional surface of the artificial joint. Consequently, the life of the artificial joint can be extended by the patterning on the frictional surfaces.
  • 青木 良太, 西村 生哉, 三田村 好矩  精密工学会大会学術講演会講演論文集  2000-  (2)  2000/09/01  [Not refereed][Not invited]
  • ITO H  日本整形外科學會雜誌  74-  (8)  2000/08/25  [Not refereed][Not invited]
  • HIGA M  日本整形外科學會雜誌  74-  (8)  2000/08/25  [Not refereed][Not invited]
  • OMIZU N  日本整形外科學會雜誌  74-  (8)  2000/08/25  [Not refereed][Not invited]
  • HIGA Masaru, NISHIMURA Ikuya, TANINO Hiromasa, MITAMURA Yoshinori  年次大会講演論文集 : JSME annual meeting  2000-  (2)  61  -62  2000/07/31  [Not refereed][Not invited]
     
    Fatigue failure of the acrylic cement and resulting disruption of the bone-cement interface can limit the long-term clinical success of the cemented artificial hip joint. In order to overcome this problem optimal shape design prosthesis is required. This study describe a result of the design shape analysis (DSA) and the numerical shape optimization whereby the finite element method is used to determine optimal shape for the femoral stem of hip prosthesis in order to minimize the maximal value of the 1^<st> principal stress at the cement mantle.
  • 谷野 弘昌, 伊藤 浩, 大浦 久典, 西村 生哉, 比嘉 昌, 三田村 好矩, 勇田 敏夫, 松野 丈夫  日本整形外科學會雜誌 = The Journal of the Japanese Orthopaedic Association  73-  (8)  1999/08/25  [Not refereed][Not invited]
  • 伊藤 浩, 金田 清志, 松野 丈夫, 谷野 弘昌, 勇田 敏夫, 西村 生哉  日本整形外科學會雜誌 = The Journal of the Japanese Orthopaedic Association  73-  (8)  1999/08/25  [Not refereed][Not invited]
  • NISHIMURA Ikuya, YUHTA Toshio, ITOH Hiroshi, HIRAYAMA Mitsuhisa, SHIKATA Jitsuto, TANINO Hiromasa, MATSUNO Takeshi  生体材料  16-  (5)  254  -259  1998/10/10  [Not refereed][Not invited]
  • 西村 生哉, 四方 實人, 三田村 好矩, 勇田 敏夫, 比嘉 昌  精密工学会大会学術講演会講演論文集  1998-  (2)  393  -393  1998/09/01  [Not refereed][Not invited]
  • ITO H  日本整形外科學會雜誌 = The Journal of the Japanese Orthopaedic Association  72-  (8)  1998/08/25  [Not refereed][Not invited]
  • SHIKATA Jitsuto, NISHIMURA Ikuya, SHIMOOKA Toshiyuki, YUHTA Toshio, SHIMIZU Koichi  IEICE technical report. ME and bio cybernetics  97-  (622)  9  -14  1998/03/20  [Not refereed][Not invited]
     
    One of the reasons of osteolysis has been recognized to be the wear particles of ultra-high molecular weight polyethylene (UHMWPE). We examined the effectiveness of "patterning" and "high sphericity" to prolong the life of an artificial hip joint by preventing the production of the wear debris. The artificial hip joints used in this study were those commercially available for implantation. A pendulum hip joint simulator was developed for friction tests. The load was 200kgf on the friction surface and the range of swing was 60 degrees. The number of swings was one million in the frequency of...
  • ITO H  日本整形外科學會雜誌 = The Journal of the Japanese Orthopaedic Association  71-  (8)  1997/08/25  [Not refereed][Not invited]
  • 李 桓成, 西村 生哉, 下岡 聡行, 勇田 敏夫  精密工学会大会学術講演会講演論文集  1997-  (1)  1289  -1290  1997/03/01  [Not refereed][Not invited]
  • 李 恒成, 西村 生哉, 下岡 聡行, 勇田 敏夫  精密工学会大会学術講演会講演論文集  1996-  (2)  239  -240  1996/09/01  [Not refereed][Not invited]
  • 藤丸 真南海, 勇田 敏夫, 西村 生哉  精密工学会大会学術講演会講演論文集  1996-  (1)  343  -344  1996/03/01  [Not refereed][Not invited]
  • NISHIMURA Ikuya, YUHTA Toshio, ITOH Hiroshi, KISIMOTO Takafumi, GOTOH Ryuuji, MATSUNO Takeo, KANEDA Kiyoshi  生体材料  13-  (6)  266  -271  1995/12/01  [Not refereed][Not invited]
  • NISHIMURA Ikuya, YUHTA Toshio, MATSUBARA Yoshihiro  Journal of the Japan Society of Precision Engineering  61-  (4)  576  -580  1995/04/05  [Not refereed][Not invited]
     
    Experimental study was carried out on the properties of hydroxyapatite(HAp) films that was deposited by RF-sputtering on the polymer(silicone rubber, PET). During sputtering, the polymer were cooled by especially manufactured water-cooled unit. Though the adhesion strength between the HAp film and PET is not strong, that between the HAp film and silicone rubber is quite strong nearly equal to the fracture strength of silicone rubber. Although every HAp film has amorphous structure, it is possible to crystallize by soaking the films in the Hanks' solution. These results arc useful to develop...
  • NISHIMURA Ikuya, YUHTA Toshio, SAITOH Tsuyoshi  Journal of the Surface Finishing Society of Japan  43-  (6)  584  -588  1992  [Not refereed][Not invited]
     
    This paper presents the mechanical characteristics and structures of titanium nitride (TiN) films formed by reactive sputter deposition. TiN films formed at N2 partial pressures below 2.0×10-3Pa are almost pure titanium and have a fibrous structure. It is thought that nitrogen collects in the dislocations. Films formed at N2 partial pressure of 2.0×10-3Pa were hardest and had the lowest coefficients of friction. They had a double structures, with a fine-grain structure above a columnular structure and it is thought that hardness was due to the existence of the fine-grain structure. Films fo...

Industrial Property Rights

  • United States Patent 5462362:Wear Resisting Slide Member  
    Yuhta Toshio, Nishimura Ikuya, Kano Daijiro, Saitou Tsuyoshi, Suzuki Tomita, Tanaka Mamoru
  • 特開2003-4043(P2003-4043A):耐摩耗性摺動部材.  
    勇田敏夫, 西村生哉, 家納大次郎, 斉藤剛, 鈴木富太, 田中守
  • 特開平8-4770:耐摩耗性摺動部材  
    勇田敏夫, 西村生哉, 斉藤剛, 鈴木富太, 田中守

Educational Activities

Teaching Experience

  • Bioengineering
    開講年度 : 2020
    課程区分 : 修士課程
    開講学部 : 情報科学研究科
    キーワード : 遺伝情報, genetic information, バイオインフォマティクス, bioinformatics, イメージング, imaging, 生体医工学, biomedical engineering, 細胞力学, cell mechanics
  • Bioengineering
    開講年度 : 2020
    課程区分 : 博士後期課程
    開講学部 : 情報科学研究科
    キーワード : 遺伝情報, genetic information, バイオインフォマティクス, bioinformatics, イメージング, imaging, 生体医工学, biomedical engineering, 細胞力学, cell mechanics
  • Exercise in Bioengineering and Bioinformatics Ⅰ
    開講年度 : 2020
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 電磁気学,線形システム論,信号処理,電気・電子・ディジタル回路
  • Bioengineering and Bioinformatics Laboratory Ⅱ
    開講年度 : 2020
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : 遺伝情報,生体電気現象,生体機能情報,生体計測,バイオエレクトロニクス
  • Bases of Biomechanics
    開講年度 : 2020
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : DNA、タンパク質、細胞、細胞骨格、細胞膜、骨格・関節、力学、レオロジー、流体、筋出力、キネマトロジー 
  • Biomaterials and Biomechanics
    開講年度 : 2020
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : DNA、タンパク質、細胞、細胞骨格、細胞膜、骨格・関節、力学、レオロジー、流体、筋出力、キネマトロジー 
  • Exercise in Applied Mathematics I
    開講年度 : 2020
    課程区分 : 学士課程
    開講学部 : 工学部
    キーワード : ベクトル空間,線形写像,連立方程式,固有値,勾配,発散,回転,ストークスの定理


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