研究者業績
基本情報
経歴
3-
2015年7月 - 現在
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2006年10月 - 2015年6月
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2004年4月 - 2006年9月
学歴
2-
1998年4月 - 2003年3月
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1993年4月 - 1997年3月
委員歴
8-
2023年4月 - 現在
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2019年4月 - 現在
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2017年4月 - 現在
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2011年4月 - 現在
受賞
2論文
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Journal of Experimental Orthopaedics 10(130) 2023年12月 査読有り筆頭著者責任著者
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Journal of Orthopaedics 43 1-5 2023年9月 査読有り筆頭著者責任著者
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Journal of Biomechanical Science and Engineering 17(3) 22-00060 2022年 査読有り筆頭著者責任著者
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The Knee 29 167-173 2021年2月23日 査読有り最終著者責任著者BACKGROUND: Correction of coronal plane deformity by osteotomies around the knee is theoretically three-dimensional (3D) and can be associated with changes in other planes. It has been shown that 3D rotational changes are induced by biplanar high tibial osteotomy; however, relevant information in biplanar lateral closed-wedge distal femoral osteotomy (LCW-DFO) has not been reported in literatures. This study aimed to investigate rotational changes in axial and sagittal planes in LCW-DFO using computer-aided design (CAD) simulations. METHODS: LCW-DFO is composed of three cuts: one ascending cut and two transverse cuts. In the simulations, the following geometrical parameters were adopted as factors potentially influencing 3D changes occurring in the osteotomy. The ascending cut angle measured as the angle between the edge of the ascending cut and the edge of the transverse cut in the lateral view, and the ascending cut obliquity measured as the angle corresponding to anterior/posterior inclination of the ascending cut with reference to the posterior condylar tangent line in the axial view. In the analysis, the effects of these bony cut angles on associated rotational changes in the axial and sagittal planes (internal/external rotation and flexion/extension) were calculated. Variation of wedge size ranged from 2 to 8 mm. RESULTS: The degree of the ascending cut obliquity substantially correlated with associated change in the sagittal plane (extension/flexion) while inducing only minimal change in rotation in the axial plane (internal/external rotation). When the osteotomy was made without ascending cut obliquity, the change in knee extension/flexion was minimal for the conditions analyzed while coupled internal rotation of the distal bony segment was induced. CONCLUSIONS: In biplanar LCW-DFO, the ascending cut angle substantially influenced the amount of internal rotation of the distal bony segment with little effect on flexion/extension angles. By contrast, ascending cut obliquity in the axial plane yields an effect on flexion/extension angles and little effect on internal rotation of the distal bony segment.
MISC
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APCMBE 2020, IFMBE Proceedings 82 1-6 2020年5月 査読有り筆頭著者
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Proceedings of the Seventh International Symposium on Aero Aqua Bio-mechanisms 89-93 2018年8月
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年次大会 : Mechanical Engineering Congress, Japan 2015 "J2210201-1"-"J2210201-3" 2015年9月13日Titanium tends to seizure with other metals, so titanium unfits thread rolling for dental implant with φ3mm diameter or less. Therefore we lubricate the contact point and prevent the seizure by applying a textured surface on the die. We were examined for the textured surface for reducing the shear stress by plastically deformed analysis between titanium material and die, and fluid analysis of the oil around the textured surface. From this analysis, texture provides an effective of low-friction, and a dimple type texture reduces shear stress by 28%.
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WORLD CONGRESS ON MEDICAL PHYSICS AND BIOMEDICAL ENGINEERING, 2015, VOLS 1 AND 2 51 346-349 2015年This study is aimed to show if hip joint loads during walking could be reduced by a slight gait modification. Six healthy adult subjects (mean (SD) age 22 (0.0) years, mean (SD) height 1.68 (0.04) m, mean (SD) weight 60.2 (7.9) kg) took part in this study. A series of normal walking trials at a self-selected speed (step length and cadence) and stride width were performed. After subjects had gait retraining during in which they were asked to alter their stride width by increasing abduction angles without changing any other kinematics. Subjects walked 10 trials for each gait pattern. A total of 20 trials were performed. Experimental gait data (joint angles and ground reaction forces) and musculoskeletal computer models were used to quantify individual hip joint moments. We used adduction moments as an indicator of internal hip joint loads. An inverse dynamics approach was also used to calculate the hip moments during a stance phase. Changes in abduction angles did not have any effect on the shape of the hip adduction moment curve but changed its peak mean magnitudes. In conclusion, we showed that a modified gait pattern can reduce the hip adduction moment. Given the results of this study, we believe that gait retraining may be an acceptable, noninvasive option for the treatment of patients of OA.
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バイオフロンティア講演会講演論文集 2014(25) 143-144 2014年10月2日
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IFMBE Proceedings 43 311-314 2014年Passive muscle tension around the hip joint following total hip arthroplasty (THA) plays an important role in post-surgery dislocation mechanisms, especially posterior dislocation. To analyze dislocation objectively and to clarify the distinction between implant-to-implant impingement and dislocation, three-dimensional finite element (FE) models of hybrid THA components were generated. An acetabular component was implanted into the acetabulum in 20 degrees of anteversion and 45 degrees of inclination. The bearing surface had 26 mm hemispherical plus 1 mm flat depth and a chamfered edge. In this study, posterior dislocation-prone movements such as flexion, adduction, internal rotation, and their combinations were analyzed, starting with the femoral component oriented in a manner corresponding to the hip being flexed to impingement with 0°, 10°, 20°, and 30° of internal rotation and 0°, 10°, 20°, and 30° of adduction. The nonlinear explicit FE simulations were driven by inputting a series of incremental flexion moments and hip joint forces concurrently. The angles of internal rotation and adduction affected both impingement and dislocation angles of flexion. The flexion angles both at impingement and dislocation decreased by increasing the internal rotation angles. Although the peak flexion moment to make the hip joint dislocate increased by increasing the internal rotation angle, it didn’t always increase with an increase in the adduction angle. The highest value of the peak flexion moment to dislocation was observed at 30° of internal rotation. Conversely, the lowest value of the peak flexion moment was observed at 10° of adduction. This lowest value means that the hip joint is easy to dislocate at this adduction angle.
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年次大会 : Mechanical Engineering Congress, Japan 2013 "J024025-1"-"J024025-4" 2013年9月8日A contact lens (CL) is medical equipment correcting refraction abnormalities such as myopia, hyperopia and astigmatism. Recently, a study to evaluate the optical properties of wearing CL has begun to improve the quality of vision. However, it is hardly studied the shape change of CL affecting the optics properties. In particular, because a soft contact lens (SCL) is soft material, it is thought that the deformation behavior of wearing CL influences optics properties. In this study, the shape change of wearing SCL is calculated using a finite element method and the optical properties were evaluated using an optics design evaluation soft "CODE V". Following results were mainly obtained. (1) The front curve value of commercial SCL was decided by an eye model. (2) The shape change of SCL ocurred along the cornea and slightly warped at the bevel by wearing SCL. (3) The defocus aberration and the lens diopter slightly increased by wearing SCL.
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年次大会 : Mechanical Engineering Congress, Japan 2011 "W111003-1"-"W111003-3" 2011年9月11日A new type of solid particle impact test, which is called Micro-Slurry-jet Erosion (MSE) test, is proposed recently. MSE test can evaluate the wear properties of thin, single layered or multilayered physical vapor deposited (PVD) coatings. In the MSE test, a slurry containing 1.2m alumina particles was impacted at high velocity about 100m/s perpendicular to thin PVD coatings. But MSE test needs to choose both of the impact velocity and the impact angle from the information about the grain size of alumina particle, or thickness and mechanical properties of hard coating , to obtain the optimum wear rate. The Discrete Element Method (DEM) is a numerical method used to compute the movements of particle in the slurry jet or fracture of brittle specimen consisted of a large number of particles such as grain architecture in the hard coating. This paper explores for the impactive fracture simulation, i.e. the crack initiation and propagation in thin hard coating, caused by the attack of slurry jet using the DEM model. A mathematical model taking into account adhesion, abrasion and impact wear which occur between the alumina particle in slurry and the thin hard coating is derived in order to predict the loss of material on coating. Our DEM simulated predictions are compared to published experimental data.
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バイオエンジニアリング講演会講演論文集 2010(23) 43-44 2011年1月7日
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年次大会講演論文集 2008 23-24 2008年Less invasive hemostatic clamp is proposed and made experimentally. Clamping mechanism of this instrument is based on the conventional one, and utilizes superelastic behavior of an shape memory alloy wire. First, its clamping property was estimated experimentally without any animal experiments, considering whether the deformation property of an SMA wire affects clamping property. From these experiments, it was found that this newly occlusive instrument had less invasiveness compared with conventional ones.
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7th Japan-France Joint Seminar on Intelligent Materials and Systems 2006 9 2006年6月
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ARTIFICIAL ORGANS 29(11) 912-915 2005年11月A rotary blood pump ( RP) is desirable as a small ventricular assist device (VAD). However, an RP is non-pulsatile. We tried to develop a device that attaches a pulse to the RP. We also tried to develop a pulse-generating equipment that was not air-pressure driven. The ball screw motor was considered a candidate. The application of a small-sized shape memory alloy was also attempted. An electrohydraulic system was adopted, and actuator power was connected to the diaphragm. The diaphragm was placed on the outer side of the ventricle. Most RPs that have been developed all over the world drain blood from the ventricle. The wave of a pulse should be generated if a pulse is added by the drawn part. The output assistance from the outer side of the ventricle was attempted in animal experiments, and the device operated effectively. This device can be used during implantable operation of RP. This may serve as an effective device in patients experiencing problems in peripheral circulation and in the function of internal organs.
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ASAIO JOURNAL 50(4) 338-343 2004年7月This article describes an implantable artificial anal sphincter using shape memory alloys and its in vivo assessment in porcine models. The new design was developed as a low invasive prosthesis with a simple structure to solve the problem of severe fecal incontinence in patients with hypoplastic sphincters or without anal sphincters and especially for ostomates. The artificial anal sphincter consists of two shape memory alloy (SMA) plates as the main functional parts to perform two basic functions when the SMA artificial sphincter is fitted around intestines (i.e., an occlusion at body temperature and an opening function on heating). Our previous assessments with short-term animal experiments revealed promising properties with the occlusion function of the device, although some complications, such as overpressure induced ischemia, heat burn, and infections, remained. This article addresses the concerns related to the practical use of the device, the power supplement to drive the actuator, and overheating protection of the device inside bodies. Results of chronic animal experiments of up to 4 weeks suggested great potential for the improved device.
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MATERIALS TRANSACTIONS 45(2) 272-276 2004年2月Shape memory alloys (SMAs) have the features of large force-to-weight ratio and large deformation, are considered suitable for actuator uses. This paper describes the applications of an SMA material with two-way shape memory as artificial muscles for the treatment of fecal incontinences. Two designs of the proposed artificial sphincters are presented; one for a complete replacement of the anal sphincter and the other as an auxiliary sphincter to assist the puborectal muscles for maintaining fecal continence. Their functional evaluations have been conducted through fundamental experiments on the thermal responses and the mechanical deformation. The functionality of both was confirmed by in vitro experiments. The first design, the artificial anal sphincter was subjected to animal experiments for up to 4 weeks. Satisfactory results in respects of the biofunctionality of the SMA artificial sphincter imply its potential for practical uses.
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ARTIFICIAL ORGANS 27(1) 2-7 2003年1月Tohoku University has developed various artificial organs over the last 30 years. Pneumatic driven ventricular assist devices with a silicone ball valve have been designed by the flow visualization method, and clinical trials have been performed in Tohoku University Hospital. On the basis of these developments, a pneumatic driven total artificial heart has been developed and an animal experimental evaluation was conducted. The development of artificial organs in Tohoku University has now progressed to the totally implantable type using the transcutaneous energy transmission system with amorphous fibers for magnetic shielding. Examples of implantable systems include a vibrating flow pump for ventricular assist device, an artificial myocardium by the use of shape memory alloy with Peltier elements, and an artificial sphincter for patients with a stoma. An automatic control system for artificial organs had been developed for the ventricular assist devices including a rotary blood pump to avoid suction and to maintain left and right heart balance. Based upon the technology of automatic control algorithm, a new diagnostic tool for evaluating autonomic nerve function has been developed as a branch of artificial organ research and this new machine has been tested in Tohoku University Hospital. Tohoku University is following a variety of approaches aimed at innovation in artificial organs and medical engineering fields.
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MATERIALS TRANSACTIONS 43(5) 1052-1056 2002年5月An application of shape memory alloys (SMAs) for artificial anal sphincters is presented. The artificial anal sphincter consists of two all-round shapre memory alloy (ARSMA) plates as the main functional parts,and heaters attached on SMA plates for generating thermal cycles, required for phase transformation accompanied shape changes of the plates. The SMA artificial sphincter could be fitted around intestines. performing an occlusion function at body temperature and a release function upon heating. For reducing the potential of infection, a transcutaneous energy transmission JET) system is incorporated into the artificial anal sphincter. facilitating, the complete implantation of the device. Investigation on the thermomechanical responses of the artificial sphincter has been conducted, with both the in vitro and in vivo experiments. showing great potential of practical uses. The relation between the values of applied power and the response times, and the thermo compatibility of the device are discussed.
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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6月15日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。
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日本整形外科學會雜誌 = The Journal of the Japanese Orthopaedic Association 73(8) S1699 1999年8月25日
書籍等出版物
1
講演・口頭発表等
72-
12th Asian-Pacific Conference on Biomechanics 2023年11月15日
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12th Asian-Pacific Conference on Biomechanics 2023年11月15日
共同研究・競争的資金等の研究課題
10-
日本学術振興会 科学研究費補助金 2021年4月 - 2024年3月
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科学研究費補助金（基盤C) 2018年 - 2020年
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村田学術振興財団 村田学術振興財団研究者海外派遣援助 2018年4月 - 2019年3月
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Orthosensor, Inc. 共同研究 2017年4月 - 2018年3月
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科学研究費補助金（国際共同研究加速基金） 2015年 - 2018年