研究者データベース

西村 生哉(ニシムラ イクヤ)
情報科学研究院 生命人間情報科学部門 バイオエンジニアリング分野
助教

基本情報

所属

  • 情報科学研究院 生命人間情報科学部門 バイオエンジニアリング分野

職名

  • 助教

学位

  • 博士(工学)(北海道大学)

ホームページURL

J-Global ID

研究キーワード

  • 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   

研究分野

  • ライフサイエンス / 生体材料学
  • ライフサイエンス / 生体医工学

職歴

  • 2004年 - 2005年 北海道大学 大学院・情報科学研究科 助手

研究活動情報

論文

  • Masaru Higa, Hiromasa Tanino, Ikuya Nishimura, Yoshinori Mitamura, Takeo Matsuno, Hiroshi Ito
    JOURNAL OF ARTIFICIAL ORGANS 18 1 79 - 85 2015年03月 [査読有り][通常論文]
     
    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 2013年 [査読有り][通常論文]
     
    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
    人工臓器 35 4 404 - 410 2011年04月 [査読有り][通常論文]
     
    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
    人工臓器 14 1 23 - 30 2011年03月 [査読有り][通常論文]
     
    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 2010年 [査読有り][通常論文]
     
    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
    人工臓器 33 9 770 - 773 2009年09月 [査読有り][通常論文]
     
    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.
  • 安部 玲央奈, 西村 生哉, 泉澤 康晴
    The journal of veterinary medical science 70 11 1191 - 1198 社団法人日本獣医学会 2008年11月25日 [査読無し][通常論文]
     
    人工関節は重度に損傷された関節に対し適応される.セメントレス人工関節表面にコーティングされる骨形成のためのポーラス構造は,荷重により剥離し骨固着性が減弱するとの報告がある.本研究では,表面構造一体型である従来のGrit-blastより4〜11倍の表面粗さ33.4μmの改良型Grit-blastの検討を行った.7頭の健常ビーグル犬の左大腿骨に4本の改良型Grit-blastインプラントを,対照に右大腿骨に4本のSmoothインプラントを埋植して16週まで4週毎に観察した.改良型Grit-blastは組織学的また力学的にも良好な結果を得た.インプラント表面への骨の生長は12週で76.38%,16週で74.13%と高い結果となった.破断剪断応力は実験終了時まで増加し,14.5MPaと臨床的にも許容できる結果となった.骨基質の密度は特に16週目において高く,新生骨の成熟の進行がGrit-blastの粗面構造に適合していることが示唆された.インプラント挿入部位は生体学的また力学的に十分な皮質骨を選択する必要があり,またインプラント挿入時はルーズニングを防止するため強固に固定することに注意しなければならない.今回考案した改良型Grit-blastはセメントや他のコーティングの併用が無くても比較的良好な骨固着性が得られ,加工が容易であることから人工関節の表面構造として有用であると考えられた.
  • 加納 健太郎, 高橋 紗佳, 甘利 修一, 西村 生哉, 村林 俊, 岡本 英治, 三田村 好矩
    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年11月21日 [査読無し][通常論文]
  • 石田 敏真, 西村 生哉, 三田村 好矩, 谷野 弘昌, 伊藤 浩, 松野 丈夫
    生体医工学 : 日本エム・イー学会誌 46 2 226 - 231 社団法人日本生体医工学会 2008年04月10日 [査読無し][通常論文]
     
    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 ...
  • 機械的接触部を持たない軸流血液ポンプの開発
    Y.MITAMURA, K.KIDO, T.YANO, D.SAKOTA, R.YOZU, E.OKAMOTO, S.MURABAYASHI, I.NISHIMURA
    Biocybernetics and Biomedical Engineering 27 139 - 146 2007年 [査読有り][通常論文]
  • 西村 生哉, 石田 敏真, 村林 俊, 三田村 好矩, 中村 聡喜, 伊藤 浩, 松野 丈夫, 比嘉 昌, 長谷井 稔, 藏本 孝一
    生体医工学 : 日本エム・イー学会誌 = Transactions of the Japanese Society for Medical and Biological Engineering : BME 44 1 77 - 84 社団法人日本生体医工学会 2006年03月10日 [査読無し][通常論文]
     
    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.
  • セメントレスグリッドブラストインプラントの結合力評価
    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年 [査読有り][通常論文]
  • H. Tanino, H. Ito, M. Higa, N. Omizu, I. Nishimura, K. Matsuda, Y. Mitamura, T. Matsuno
    JOURNAL OF BIOMECHANICS 39 10 1948 - 1953 2006年 [査読有り][通常論文]
     
    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.
  • 石田 敏真, 八木橋 厚太, 西村 生哉, 谷野 弘昌, 伊藤 浩, 松野 丈夫, 三田村 好矩, 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 2005年10月01日 [査読無し][通常論文]
  • 矢野 哲也, 見藤 歩, 三田村 好矩, 西村 生哉, 村林 俊, 四津 良平
    生体医工学 : 日本エム・イー学会誌 43 1 85 - 92 社団法人日本生体医工学会 2005年03月10日 [査読無し][通常論文]
     
    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...
  • 谷野 之紀, 比嘉 昌, 西村 生哉, 石田 敏真, 大畑 昇, 三田村 好矩
    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 2004年11月01日 [査読無し][通常論文]
  • 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 2004 5 129 - 130 一般社団法人日本機械学会 2004年09月04日 [査読無し][通常論文]
     
    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.
  • 八木橋 厚太, 三田村 好矩, 西村 生哉, 石田 敏真, 伊藤 浩, 谷野 弘昌, 中村 聡喜, 松野 丈夫
    電子情報通信学会技術研究報告. MBE, MEとバイオサイバネティックス 104 129 21 - 23 一般社団法人電子情報通信学会 2004年06月11日 [査読無し][通常論文]
     
    THA(total hip arthroplasty)においてステム部分とカップ部分におけるprosthetic impingementは、インプラントの設置角と形状の変化により違いを生じることがわかっている。本研究ではそれらの変化がどの程度可動域(ROM range of motion)に影響を及ぼすのかをコンピューター上で測定し、それぞれの因子に対し検討することを目的とした。測定は、impingementが起こる角度を屈曲・進展・内転の3方向でインプラントの設置角・形状を変化させて全324通り行った。その結果それぞれの因子がどのように影響するかわかり、特にネック径を減少させることで可動域の増加が期待できることが示唆された。
  • 瀬野 貴弘, 泉澤 康晴, 西村 生哉, 前原 誠也, 久代 季子, ウマル モハメドアハメド, 若生 晋輔, 山下 和人, 小谷 忠生
    The journal of veterinary medical science 66 3 315 - 318 社団法人日本獣医学会 2004年03月25日 [査読無し][通常論文]
     
    表面をねじ切り加工しレーザーで小孔を形成したスクリュー+レーザー(SL)カラムと,従来のビーズコーティング(BC)を行ったカラムを犬の大腿骨骨幹部に埋植し,骨固着性を比較した.その結果SLカラムの破断剪断強度はBCカラムとほぼ同値を示し,12週後の骨-カラム接触率は有意に高値を示した.SL表面は,従来のBC表面とほぼ同等の骨固着を有し,表面構造の剥離の恐れが無いことから,人工関節の多孔性表面として有用であると考える.
  • 瀬野 貴弘, 泉澤 康晴, 西村 生哉, 前原 誠也, 横山 季子, 山下 和人, 小谷 忠生
    The journal of veterinary medical science 65 3 s・viii - s・ix, 419-422 社団法人日本獣医学会 2003年03月25日 [査読無し][通常論文]
     
    アーク蒸着法で表面を多孔質処理したチタニウム(Ti-6Al-4V)の円筒に,スパッタリング法を用いて膜厚5μmのハイドロキシアバタイト(HA)をコーティングした.これらの円筒とHAをコーティングしていない円筒をイヌの大腿骨骨幹部に埋植し,骨固着性を比較した,その結果,HAコーティング円筒の固着性の方が強い傾向があった.インプラント表面の多孔質処理およびHAスパッタリング法は,良好な骨の内方成長(bone-ingrowth)をもたらしうると推察された.
  • 比嘉 昌, 西村 生哉, 谷野 弘昌, 伊藤 浩, 松野 丈夫, 三田村 好矩
    日本機械学会論文集. A編 = Transactions of the Japan Society of Mechanical Engineers. A 69 679 689 - 694 一般社団法人日本機械学会 2003年03月25日 [査読無し][通常論文]
     
    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.
  • 比嘉 昌, 西村 生哉, 谷野 弘昌, 伊藤 浩, 石田 敏真, 松野 丈夫, 三田村 好矩
    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 2002年11月01日 [査読無し][通常論文]
  • 大腿骨CT画像からの骨アウトライン抽出
    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 [査読有り][通常論文]

書籍

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

その他活動・業績

  • 石田 敏真, 西村 生哉, 谷野 弘昌, 伊藤 浩, 松野 丈夫, 三田村 好矩 年次大会講演論文集 : JSME annual meeting 2005 (5) 207 -208 2005年09月18日 [査読無し][通常論文]
     
    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...
  • 比嘉 昌, 西村 生哉, 前田 冬彦, 瀬野 貴弘, 泉澤 康春, 三田村 好矩 年次大会講演論文集 : JSME annual meeting 2004 (5) 127 -128 2004年09月04日 [査読無し][通常論文]
     
    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...
  • 矢野 哲也, 見藤 歩, 関根 一光, 三田村 好矩, 西村 生哉, 村林 俊, 四津 良平 年次大会講演論文集 : JSME annual meeting 2004 (5) 189 -190 2004年09月04日 [査読無し][通常論文]
     
    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年06月10日 [査読無し][通常論文]
  • 関根 一光, 三田村 好矩, 村林 俊, 西村 生哉, 四津 良平 年次大会講演論文集 : JSME annual meeting 2003 (5) 95 -96 2003年08月05日 [査読無し][通常論文]
     
    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 ...
  • 清水 亮太, 西村 生哉, 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 2003 (7) 141 -142 2003年08月05日 [査読無し][通常論文]
     
    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年03月10日 [査読無し][通常論文]
  • 石田 敏真, 西村 生哉, 比嘉 昌, 三田村 好矩 バイオエンジニアリング講演会講演論文集 2003 (15) 409 -410 2003年01月20日 [査読無し][通常論文]
  • 石田 敏真, 西村 生哉, 比嘉 昌, 三田村 好矩 年次大会講演論文集 : JSME annual meeting 2002 (6) 53 -54 2002年09月20日 [査読無し][通常論文]
     
    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...
  • 比嘉 昌, 西村 生哉, 谷野 弘昌, 伊藤 浩, 松野 丈夫, 三田村 好矩 精密工学会誌 = Journal of the Japan Society of Precision Engineering 68 (7) 948 -952 2002年07月05日 [査読無し][通常論文]
     
    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.
  • 佐藤 俊介, 三田村 好矩, 平山 泰志, 勇田 敏夫, 西村 生哉 電子情報通信学会技術研究報告. MBE, MEとバイオサイバネティックス 102 (137) 9 -12 2002年06月14日 [査読無し][通常論文]
     
    デジタル画像を用いた歯色の客観的な測定法の開発を目的とした基礎的研究を行った。被験者、シェードガイドおよび参照用色見本を、標準白色光(D65)および蛍光灯下でデジタルカメラを用いて撮影した。また歯科医による被験者の歯の色の診断、歯科用色彩計によるシェードガイドの色の測定を行った。撮影された画像から対象のRGB値を測定し、マンセル表色系とCIEL^*a^*b^*表色系に変換したのち、歯科医による診断、歯科用色彩計による色の測定との比較を行った。さらに同一条件下で5日間反復実験を行い、再現性を評価した。その結果、本手法で歯の色を測定できる可能性が示された。
  • 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年06月10日 [査読無し][通常論文]
  • 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年03月01日 [査読無し][通常論文]
  • 松田 雄弘, 西村 生哉, 谷野 弘昌, 比嘉 昌, 三田村 好矩 年次大会講演論文集 : JSME annual meeting 0 (1) 79 -80 2001年08月22日 [査読無し][通常論文]
     
    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...
  • 松野 丈夫, 谷野 弘昌, 大水 信幸, 西村 生哉, 伊藤 浩 旭川医科大学研究フォーラム 2 (1) 30 -35 2001年06月30日 [査読無し][通常論文]
     
    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
  • 松田 雄弘, 西村 生哉, 谷野 弘昌, 比嘉 昌, 三田村 好矩 電子情報通信学会技術研究報告. MBE, MEとバイオサイバネティックス 101 (130) 9 -14 2001年06月15日 [査読無し][通常論文]
     
    全人工股関節の緩みの主な原因の一つに、骨セメント内における応力集中による骨セメントの破壊があげられる。本研究では、有限要素法(FEM)解析にアダプティブP法を用いて、骨セメント内における応力を減少させるステム形状について最適設計を行った。3次元CADにより全人工股関節のモデリングし、3次元FEMにより、静解析、DSA(Design Sensitivity Analysis)、最適化計算を行った。その結果、ステム断面形状を変えることで、骨セメント内の応力を減少させることに成功した。
  • 比嘉 昌, 西村 生哉, 松田 雄弘, 谷野 弘昌, 大水 信幸, 三田村 好矩 バイオエンジニアリング講演会講演論文集 2001 (13) 154 -155 2001年01月15日 [査読無し][通常論文]
  • 西村 生哉, 比嘉 昌, 勇田 敏夫, 伊藤 浩, 谷野 弘昌, 大水 信幸, 村林 俊, 三田村 好矩 精密工学会誌 = Journal of the Japan Society of Precision Engineering 66 (10) 1594 -1598 2000年10月05日 [査読無し][通常論文]
     
    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年09月01日 [査読無し][通常論文]
  • 伊藤 浩, 大浦 久典, 松野 丈夫, 谷野 弘昌, 大水 信幸, 勇田 敏男, 西村 生哉 日本整形外科學會雜誌 74 (8) 2000年08月25日 [査読無し][通常論文]
  • 比嘉 昌, 西村 生哉, 谷野 弘昌, 大水 信幸, 松田 雄弘, 伊藤 浩, 松野 丈夫, 三田村 好矩 日本整形外科學會雜誌 74 (8) 2000年08月25日 [査読無し][通常論文]
  • 大水 信幸, 伊藤 浩, 谷野 弘昌, 西村 生哉, 比嘉 昌, 松田 雄弘, 三田村 好矩, 松野 丈夫 日本整形外科學會雜誌 74 (8) 2000年08月25日 [査読無し][通常論文]
  • 比嘉 昌, 西村 生哉, 谷野 弘昌, 三田村 好矩 年次大会講演論文集 : JSME annual meeting 2000 (2) 61 -62 2000年07月31日 [査読無し][通常論文]
     
    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年08月25日 [査読無し][通常論文]
  • 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年08月25日 [査読無し][通常論文]
  • 西村 生哉, 勇田 敏夫, 伊藤 浩, 平山 光久, 四方 實人, 谷野 弘昌, 松野 丈夫 生体材料 16 (5) 254 -259 1998年10月10日 [査読無し][通常論文]
  • 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年09月01日 [査読無し][通常論文]
  • 伊藤 浩, 金田 清志, 松野 丈夫, 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 72 (8) 1998年08月25日 [査読無し][通常論文]
  • 四方 實人, 西村 生哉, 下岡 聡行, 勇田 敏夫, 清水 孝一 電子情報通信学会技術研究報告. MBE, MEとバイオサイバネティックス 97 (622) 9 -14 1998年03月20日 [査読無し][通常論文]
     
    人工股関節のlooseningの原因として, 摺動部で発生した超高分子量ポリエチレン(UHMWPE)摩耗粉の影響が指摘されている.本研究では摩耗粉の発生を抑え, 寿命を延長させることを目的として, 人工股関節摺動部への凹パターンの形成および高真円度化の二つの手法について, その有効性を検討した.本研究で使用した試料は, すべて市販の人工股関節である.摺動試験には振り子方式関節シミュレータを用いた.摺動部に200kgfを負荷し, 振れ角60°として, 振動は1分間に20サイクルの速さで, 10^6回繰り返しを行った.摩耗量測定, 摺動面の顕微鏡観察及び表面粗さ測定の結果, 摺動面へのパターン付加および高真円度化が耐摩耗性の向上に有効であることが示された.
  • 伊藤 浩, 松野 丈夫, 金田 清志, 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 71 (8) 1997年08月25日 [査読無し][通常論文]
  • 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年03月01日 [査読無し][通常論文]
  • 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年09月01日 [査読無し][通常論文]
  • 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年03月01日 [査読無し][通常論文]
  • 西村 生哉, 勇田 敏夫, 伊藤 浩, 岸本 隆史, 後藤 龍治, 松野 丈夫, 金田 清志 生体材料 13 (6) 266 -271 1995年12月01日 [査読無し][通常論文]
  • 西村 生哉, 勇田 敏夫, 松原 良洋 精密工学会誌 61 (4) 576 -580 1995年04月05日 [査読無し][通常論文]
     
    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...
  • 西村 生哉, 勇田 敏夫, 斎藤 剛 表面技術 43 (6) 584 -588 1992年 [査読無し][通常論文]
     
    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...

特許

  • United States Patent 5462362:耐摩耗性摺動部材..  
    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

教育活動情報

主要な担当授業

  • バイオエンジニアリング特論
    開講年度 : 2019年
    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
  • バイオエンジニアリング特論
    開講年度 : 2019年
    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
  • バイオメカニクス基礎
    開講年度 : 2019年
    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 
  • 生体物理工学
    開講年度 : 2019年
    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 
  • 生体情報工学実験Ⅱ
    開講年度 : 2019年
    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
  • 応用数学演習Ⅰ
    開講年度 : 2019年
    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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