| 1. |
Wenxiao Li, Takehiro Morita, Yoshinori Sawae, Experimental study on boundary lubricity of superficial area of articular cartilage and synovial fluid, Friction, https://doi.org/10.1007/s40544-023-0822-y, 12, 5, 981-996, 2024.05, he boundary lubrication mechanism at the articulating surface of natural synovial joints has been the subject of much discussion in tribology. In this study, to elucidate the lubricating function of the superficial area of articular cartilage and synovial fluid (SF), cartilage specimens were processed with four different treatments: gentle and severe washing with detergent, incubation in NaCl solution, and trypsin digestion to selectively remove certain constituents from the cartilage surface. Subsequently, the frictional characteristics were examined in phosphate-buffered saline (PBS) and SF against glass. Angularly reciprocating sliding tests with a spherical glass probe and square articular cartilage specimens were performed at low contact loads in the mN range to extract the frictional behavior in the superficial area of the cartilage specimens. Meanwhile, the cartilage surface was observed to confirm the effects of treatments on the morphology of the cartilage surface using a fluorescence microscope and water-immersion methods. The coefficient of friction (COF) of the prepared cartilage specimens was varied from 0.05 to over 0.3 in PBS. However, a certain group of cartilage specimens exhibited a low COF of less than 0.1 with limited variation. For the low COF group of specimens, all four treatments increased the COF in PBS to different extents, and fluorescence microscopy revealed that the integrity of the cartilage surface was deteriorated by treatments. This means that the intact cartilage surface had lubricating constituents to maintain low friction, and the removal of such constituents resulted in the loss of the intrinsic boundary lubricity of the cartilage surface. The variation in the COF of the cartilage specimens was suppressed in SF because it had a clear boundary lubrication effect on the cartilage surface. The lubricating effect of SF could be confirmed even after degenerative treatment.. |
| 2. |
Chen Qian, Morita Takehiro Sawae Yoshinori, Fukuda Kanao, Sugimura Joichi
, Effects of trace moisture content on tribofilm formation, friction and wear of CF-filled PTFE in hydrogen, 10.1016/j.triboint.2023.108905, 188, 108905, 2023.10, This study investigated the effects of trace moisture in hydrogen gas on the tribological behavior of carbon fiber (CF)-filled polytetrafluoroethylene (PTFE) composites by examining 20 wt% polyacrylonitrile-based CF-reinforced PTFE composites against stainless-steel disks in gaseous hydrogen environments, where moisture content was controlled at 1, 10, 20, and 40 ppm. The results revealed tribological characteristics of the sliding couples were significantly affected by the moisture content. Wear rates of pin specimens tended to increase gradually with moisture content. Similarly, average coefficient of friction increased as moisture content increased from 1 to 20 ppm. However, it decreased upon further increasing the water content. Moreover, surface analyses of the formed tribofilms at varying moisture contents revealed significant variations in terms of the amount and structure.. |
| 3. |
David Nečas, Seido Yarimitsu, David Rebenda, Hironori Shinmori, Martin Vrbka, Yoshinori Sawae, Teruo Murakami, Ivan Křupka, On the replacement of articular cartilage: The friction of PVA hydrogel layer in hip simulator test, Tribology International, 10.1016/j.triboint.2022.108100, 178, 108100, 108100, 2023.02, The present study focuses on friction evaluation of the polyvinyl alcohol (PVA) hydrogel layer, an anticipative material for cartilage replacement. The experiments were carried out in a ball-in-socket configuration using a pendulum hip simulator. The friction coefficients of ceramic-on-hydrogel pairs were compared with those of commercial implants (metal/ceramic heads vs UHMWPE, HXPE and metal/ceramic sockets). The effects of hydrogel ageing and hydration were studied, among others. The use of PVA inserts caused up to 98% reduction in friction coefficient compared to original hip pairs. The application of PVA for local or even complete cartilage replacement seems to be an outstanding opportunity in implantology.. |
| 4. |
Andrew Chapman, Elif Ertekin, Masanobu Kubota, Akihide Nagao, Kaila Bertsch, Arnaud Macadre, Toshihiro Tsuchiyama, Takuro Masamura, Setsuo Takaki, Ryosuke Komoda, Mohsen Dadfarnia, Brian Somerday, Alexander Tsekov Staykov, Joichi Sugimura, Yoshinori Sawae, Takehiro Morita, Hiroyoshi Tanaka, Kazuyuki Yagi, Vlad Niste, Prabakaran SaravananShugo Onitsuka, Ki-Seok Yoon, Seiji Ogo, Toshinori Matsushima, Ganbaatar Tumen-Ulzii, Dino Klotz, Dinh Hoa Nguyen, George Harrington, Chihaya Adachi, Hiroshige Matsumoto, Leonard Kwati, Yukina Takahashi, Nuttavut Kosem, Tatsumi Ishihara, Miho Yamauchi, Bidyut Baran Saha, Md. Amirul Islam, Jin Miyawaki, Harish Sivasankaran, Masamichi Kohno, Shigenori Fujikawa, Roman Selyanchyn, Takeshi Tsuji, Yukihiro Higashi, Reiner Kirchheim, Petros Sofronis, Achieving a Carbon Neutral Future through Advanced Functional Materials and Technologies, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.20210323, 95, 1, 73-103, 2022.01. |
| 5. |
Shahemi, Nur Hidayah; Liza, Shahira; Sawae, Yoshinori; Morita, Takehiro; Shinmori, Hironori; Yaakob, Yazid , Effects of surface wettability and thermal conductivity on the wear performance of ultrahigh molecular weight polyethylene/graphite and ultrahigh molecular weight polyethylene/graphene oxide composites, POLYMERS FOR ADVANCED TECHNOLOGIES, 10.1002/pat.5651, 33, 6, 1916-1932, 2022.06. |
| 6. |
Lofaj, Frantisek; Tanaka, Hiroyoshi; Bures, Radovan; Kabatova, Margita; Sawae, Yoshinori, Tribochemistry of Transfer Layer Evolution during Friction in HiPIMS W-C and W-C:H Coatings in Humid Oxidizing and Dry Inert Atmospheres, COATINGS, 10.3390/coatings12040493, 12, 4, 493, 2022.04. |
| 7. |
Lofaj, Frantisek; Bures, Radovan; Kabatova, Margita; Tanaka, Hiroyoshi; Sawae, Yoshinori , Modelling of tribo-chemical reactions in HiPIMS W-C:H coatings during friction in different environments, SURFACE & COATINGS TECHNOLOGY, 10.1016/j.surfcoat.2022.128238, 434, 128238, 2022.03. |
| 8. |
Hirwani, Jaswant K.; Nishimura, Ryusei; Shinmori, Hironori; Morita, Takehiro; Sawae, Yoshinori; Sinha, Sujeet K., Epoxy (SU-8) polymer composites with Ultra-high molecular weight polyethylene and Hyaluronic acid fillers for hip prosthetic implant application, TRIBOLOGY INTERNATIONAL, 10.1016/j.triboint.2021.107399, 167, 107399, 2022.03. |
| 9. |
Lofaj, Frantisek; Tanaka, Hiroyoshi; Bures, Radovan; Sawae, Yoshinori; Kabatova, Margita; Fukuda, Kanao, The effect of humidity on friction behavior of hydrogenated HIPIMS W-C:H coatings, SURFACE & COATINGS TECHNOLOGY, 10.1016/j.surfcoat.2021.127899, 428, 127899, 2021.12. |
| 10. |
Shahemi, Nur Hidayah; Liza, Shahira; Sawae, Yoshinori; Morita, Takehiro; Fukuda, Kanao; Yaakob, Yazid, The relations between wear behavior and basic material properties of graphene-based materials reinforced ultrahigh molecular weight polyethylene, POLYMERS FOR ADVANCED TECHNOLOGIES, 10.1002/pat.5428, 32, 11, 4263-4281, 2021.11, This article aims to investigate the influence of reinforcing graphene oxide (GO) and graphite flakes (GF) fillers into ultrahigh molecular weight polyethylene (UHMWPE) for orthopedic application. These fillers were expected to physically bond to UHMWPE, thus can enhance the subsurface strength, improving the wear behavior of the composites. UHMWPE/GO and UHMWPE/GF composites were prepared at 0.1 and 1.0 wt% by melt-blending, followed by a compression molding technique. A multidirectional pin-on-disc wear test was performed to simulate the kinematic of hip application. Whilst getting exposed in the artificial in-vivo lubricant bath (30 v/v% diluted bovine serum). Following this, the wear mechanism fostered by each filler (GO and GF) was determined by wear features obtained from the optical microscope and scanning electron microscope (SEM). The crystallinity degree and crystal defect were assessed using x-ray diffraction (XRD). The mechanical properties of fabricated composites were evaluated by using a universal testing machine and Vickers microhardness. We found that UHMWPE/GO has the lowest specific wear rate due to the improved subsurface strength, as the reduction of a weak adhesive point was observed on the worn surface. Meanwhile, higher GF content (1 wt%) in UHMWPE displayed a lower specific wear rate than neat UHMWPE after completing the 10 km sliding distance attributed to the filler resurfaced, responsible for providing a strong resistance of the shear stress applied upon sliding with the metal counterface. Interestingly, the hardness and tensile strength for both UHMWPE/GO and UHMWPE/GF increased, although the crystallinity percentage was declining compared to neat UHMWPE. . |
| 11. |
Tachibana K., Atsuta I., Tsukiyama Y., Kuwatsuru R., Morita T., Yoshimatsu H., Matsushita Y., Narimatsu I., Ayukawa Y., Sawae Y., Koyano K., The need for polishing and occlusal adjustment of Zirconia prostheses for wear on antagonist teeth, Dental Materials Journal, 10.4012/dmj.2020-190, 40, 3, 650-656, 2021.03, The attrition of enamel when opposed by ceramics is of great concern. The purpose of this study was to evaluate enamel wear against high translucent zirconia Zr, lithium disilicate LD, gold Au, and enamel E with different surface and contact conditions. The materials were divided into two groups: Polished and ground n=8 each. Two-body wear tests were performed against human enamel with vertical and horizontal, horizontal, and vertical repetitive movements as experiments 1 to 3 respectively. The surface roughness of all materials except Zr changed throughout the experiments. In experiment 1, Zr and Au showed less antagonist wear when polished than when ground. In experiment 2, polished groups showed less antagonist wear than ground groups in all materials. In experiment 3, Zr and LD exerted greater antagonist wear than E, regardless of Ra. These findings confirm the importance of polishing and occlusal adjustment of zirconia. . |
| 12. |
Tetsuo Yamaguchi, Akira Akamine, Yoshinori Sawae, On/off switching of adhesion in gecko-inspired adhesives, Biosurface and Biotribology, 10.1049/bsb2.12003, 1-7, 2021.06, In this study, the adhesion‐detachment behaviour of a gecko‐inspired adhesive pad was investigated to understand the on/off switching mechanisms of adhesion in gecko feet. A macroscopic spatula model was fabricated using silicone rubber, and adhesion tests combining lateral sliding and vertical debonding were conducted. It was observed that the contact state and the adhesion force of the pad vary considerably with the direction of lateral sliding prior to debonding, and that the pad achieves adhesion during debonding even when it loses contact due to excess lateral sliding. These results explain the mech- anisms behind the on/off switching and stable adhesion of gecko feet, and suggest the possibility of developing new‐generation adhesives capable of switchable adhesion.. |
| 13. |
Masafumi Kihara, Yoichiro Ogino, Yasuyuki Matsushita, Takehiro Morita, Yoshinori Sawae, Yasunori Ayukawa, Kiyoshi Koyano, In vitro assessment of the effect of implant position on biomechanical behaviors of implant-supported removable partial dentures in kennedy class ii condition, Materials, 10.3390/ma14092145, 14, 2145, 2021.05, The purpose of this study was to investigate the effects of implant position and loading position on biomechanical behaviors using implant-supported removable partial denture (ISRPD) models in a simulated Kennedy class II partially edentulous mandible. Three types of Kennedy class II mandibular acrylic resin models (a conventional RPD without support by an implant—CRPD; models with an implant placed at first molar (#46)—MP-ISRPD— and second molar (#47)—DP-ISRPD) were used to measure vertical displacement of the RPD, mesio-distal displacement of the abutment tooth, and bending moment of the abutment tooth and implant under one-point loading. The variables at three respective loading points (#45, #46 and #47) were compared statistically. Vertical displacement was suppressed in ISRPDs compared to the CRPD, and significant effects were identified under loading at the implant position. The largest meiso-distal displacement was observed in MP-ISRPD under #47 loading. Bending moments of the abutment tooth and implant were significantly higher in MP-ISRPD than in DP-ISPRD. In MP-ISRPD, a higher bending moment of the abutment tooth under #45 and #47 loading was detected, although the bending moment in DP-ISRPD was almost zero. The results of this study suggested that MP-ISRPD shows the specific biomechanical behaviors, although DP-ISRPD might provide biomechanical benefits under all one-point loading conditions.. |
| 14. |
Teruo Murakami , Nobuo Sakai , Seido Yarimitsu , Kazuhiro Nakashima ,
Tetsuo Yamaguchi, Yoshinori Sawae, Atsushi Suzuki, Evaluation of influence of changes in permeability with aging on friction and biphasic behaviors of artificial hydrogel cartilage, Biotribology, 10.1016/j.biotri.2021.100178, 26, 100178, 2021.06, Various hydrogels have been developed to use as artificial cartilage. Poly(vinyl alcohol) (PVA) hydrogel cross- linked by hydrogen bonds is biocompatible and has similar properties to natural articular cartilage. For clin- ical use as artificial cartilage, superior tribological performance with low friction and minimal wear are required. In our previous study, three kinds of preparation methods for PVA hydrogels with high water content, i.e., the repeated freeze-thawing (FT) method, the cast-drying (CD) method and the layered hybrid method composed of FT and CD layers were applied. As hybrid gel specimens, (CD on FT) and (FT on CD) gels were prepared. The comparison between experiment and biphasic finite element analysis showed that the frictional behaviors of these PVA hydrogels at slow speed are controlled by their biphasic lubrication mechanism. After that, it was found that the biphasic properties of FT gel with heterogeneous network structure was largely changed after immersion in water for more than 6 years. In this paper, the influence of changes in permeability with aging of FT gel on friction and biphasic behaviors of PVA hydrogels was evaluated by biphasic finite element analysis. As aged FT specimens with lower permeability, four kinds of aged FT specimens with different elastic properties were evaluated. As a result, it is suggested that frictional behavior of PVA FT gels with aging can be improved by lowering of permeability in aged FT gel. Furthermore, it is expected that hybrid gel as CD on aged FT with appropriate elastic modulus can sustain superior low friction.. |
| 15. |
Yoshinori Sawae , Takehiro Morita , Kyota Takeda , Shugo Onitsuka , Jyo Kaneuti ,
Tetsuo Yamaguchi, Joich Sugimura, Friction and wear of PTFE composites with different filler in high purity hydrogen gas, TRIBOLOGY INTERNATIONAL, 10.1016/j.triboint.2021.106884, 157, 106884, 2021.05, Single-filler polytetrafluoroethylene (PTFE) composites with different filler materials are prepared and their tribological characteristics are evaluated in gaseous hydrogen to investigate the tribological function of each filler material. The results indicated that glass fibre caused severe abrasion on the cast iron sliding counterface and hence increased wear in both the composite and counterface in hydrogen. The friction and wear characteristics of polyphenylene sulphide-filled PTFE in hydrogen are similar to those in ambient air because it formed a PTFE-based transfer film on the counterface regardless of the surrounding atmosphere. On the other hand, carbon fibre-filled PTFE indicates excellent low friction and low wear in hydrogen. In this case, both the composite surface and sliding counterface are covered with carbon-rich tribofilms..  |
| 16. |
Hironori Shinmori, Mayo Kubota, Takehiro Morita, Tetsuo Yamaguchi, Yoshinori Sawae, Effects of Synovial Fluid Constituents on Friction between UHMWPE and CoCrMo, Tribology Online, https://doi.org/10.2474/trol.15.283, 15, 4, 283-292, 2020.09, In this study, the reciprocating pin-on-plate sliding test was conducted between ultra-high molecular weight polyethylene (UHMWPE) and CoCrMo alloy with test lubricants containing representative synovial fluid constituents, such as proteins, hyaluronic acid, and phospholipids, to understand their effects on the in vivo friction and wear characteristics of implanted joint prostheses. To explore some details of the friction and wear process, the wear track remaining on the UHMWPE plate specimens was morphologically analyzed by laser microscopy and chemically analyzed by Fourier transform infrared (FTIR) spectroscopy. The influence of each constituent on the rheological properties of the test lubricant was also evaluated using a rotational rheometer. We observed that proteins had a definitive impact on the friction and wear process; proteins adsorbed on the UHMWPE surface and increased friction and wear by changing the predominant friction and wear mechanism from abrasive to adhesive. Phospholipids also increased friction while hyaluronic acid decreased friction by increasing the viscosity of the lubricants and enhancing the fluid dynamic effect. However, when phospholipids and hyaluronic acid were mixed with proteins, they enhanced the entrainment of the protein molecules into the contact area and increased the wear of UHMWPE.. |
| 17. |
Takuya Yashiki, Takehiro Morita, Yoshinori Sawae, Tetsuo Yamaguchi, Subsonic to Intersonic Transition in Sliding Friction for Soft Solids, Physical Review Letters, 10.1103/PhysRevLett.124.238001, 124, 238001, 2020.06, We perform friction experiments between a compliant gel and a rigid cylinder at sliding velocities comparable to the Rayleigh wave or secondary wave velocity of the gel. We find that, when the sliding velocity exceeds the wave velocities, the contact state transitions from Hertzian like to flat punch like, resulting in the breakdown of the lubricating oil film and the abrupt increase in the friction coefficient. We succeed in deriving theoretical solutions for the contact pressure distributions and the deformation profiles in the presence of friction, which are consistent with our experimental observations.. |
| 18. |
Tetsuo Yamaguchi, Yudal Onoue, Yoshinori Sawae, Topology and Toughening of Sparse Elastic Networks, Physical Review Letters, 124, 2020.02, The toughening of sparse elastic networks, such as hydrogels, foams, or meshes against fracture is one of the most important problems in materials science. However, the principles of toughening have not yet been established despite urgent engineering requirements and several efforts made by materials scientists. Here we address the above-mentioned problem by focusing on the topology of a network. We perform fracture experiments for two-dimensional periodic lattices fabricated from rubber strings and connecters with well-defined topological structures. We find that systematic increase in the largest coordination number while
maintaining the average coordination number (¼ 4) as constant leads to significant improvement in toughness. We reproduce the observed toughening behavior through numerical simulations and confirm that the stress concentration in the vicinity of a crack tip can be controlled by the topology of the network.
This provides a new strategy for creating tough sparse elastic networks, especially hydrogels.. |
| 19. |
David Nečas, Hatsuhiko Usami, Tatsuya Niimi, Yoshinori Sawae, Ivan Křupka, Martin Hartl, Running-in friction of hip joint replacements can be significantly reduced
The effect of surface-textured acetabular cup, Friction, 10.1007/s40544-019-0351-x, 2020.01, Hip joint replacements represent the most effective way of treatment for patients suffering from joint diseases. Despite the rapid improvement of implant materials over the last few decades, limited longevity associated with wear-related complications persists as the main drawback. Therefore, improved tribological performance is required in order to extend the service life of replacements. The effect of surface texturing of ultra-high molecular weight polyethylene (UHMWPE) acetabular cup was investigated in the present study. Unique tilling method was utilized for manufacturing the dimples with controlled diameter and depths on the contact surface of the cup. The experiments with four commercial femoral components and two model lubricants were realized. The main attention was paid to a coefficient of friction considering the differences between the original and the dimpled cups. Results showed remarkable lowering of friction, in general. Focusing on the simulated human synovial fluid, friction was reduced by 40% (alumina ceramic), 38.8% (zirconia toughened ceramic), 25.5% (metal), and 9.9% (oxinium). In addition, the dimples helped to keep the friction stable without fluctuations. To conclude, the paper brings a new insight into frictional behaviour of the hip replacements during running-in phase which is essential for overall implant lifespan. It is believed that proper surface texturing may rapidly improve the life quality of millions of patients and may lead to considerable financial savings.. |
| 20. |
Nobuo Sakai, Seido Yarimitsu, Yoshinori Sawae, M. Komori, Teruo Murakami, Biomimetic artificial cartilage: Fibre-reinforcement of PVA hydrogel to promote biphasic lubrication mechanism, Biosurface and Biotribology, 10.1049/bsbt.2018.0031, 5, 1, 13-19, 2019.03. |
| 21. |
Yoshinori Sawae, Wear of UHMWPE for joint prosthesis, Handbook of Polymer Tribology, 10.1142/9789813227798_0003, 81-109, 2018.03. |
| 22. |
Maiko Mieda, Atsuta Ikiru, Yasuyuki Matsushita, Takehiro Morita, Yasunori Ayukawa, Yoshihiro Tsukiyama, Yoshinori Sawae, Kiyoshi Koyano, The effective design of zirconia coping on titanium base in dental implant superstructure, Dental Materials Journal, 10.4012/dmj.2017-022, 37, 2, 237-243, 2018.01, Zirconia exhibits good tissue compatibility and nontoxicity, making it a widely used esthetic replacement material for implant abutments. To avoid abutment-fracture, the parts composed of zirconia with a bonded metal component connected to the implant can be used. The purpose of this study was to design titanium and zirconia components with high fracture resistance at the zirconia component’s edge line. Three edge line designs of the titanium base and zirconia sleeve were made: chamfer, shoulder, and back-taper. To assess the strength of the abutment design, static loads were applied vertically and 30 degrees from the vertical axis. A test of tensile strength was also performed after chewing simulation. Conventional zirconia components mounted on a chamfer-type titanium base showed significantly lower fracture resistance than shoulder and back-taper types. This study suggests that to improve the durability of zirconia abutments with a titanium base, a back-tapered edge design is recommended.. |
| 23. |
Mechanical design assessment of zirconia abutment supported on titanium base. |
| 24. |
Teruo Murakami, Seido Yarimitsu, Nobuo Sakai, Kazuhiro Nakashima, Tetsuo Yamaguchi, Yoshinori Sawae, Importance of adaptive multimode lubrication mechanism in natural synovial joints, Tribology International, 10.1016/j.triboint.2016.12.052, 113, 306-315, 2017.09, The superior tribological performance in natural synovial joints with low friction and minimal wear appears to be actualized by not single lubrication mode but the synergistic combination of various modes from the fluid film lubrication to boundary lubrication corresponding to the severity of rubbing conditions. We have conducted the biphasic finite element analysis and some experimental studies for articular cartilage to elucidate this ingenious lubrication mechanism from the viewpoint of the adaptive multimode lubrication mechanism. In this paper, the effectiveness of different lubrication modes such as biphasic, boundary, gel-film and hydration lubrication particularly at low speed conditions is discussed.. |
| 25. |
Teruo Murakami, Seido Yarimitsu, Nobuo Sakai, Kazuhiro Nakashima, Tetsuo Yamaguchi, Yoshinori Sawae, Atsushi Suzuki, Ardian Morina, Anne Neville, Tomasz Liskiewicz, Superior lubrication mechanism in poly(vinyl alcohol) hybrid gel as artificial cartilage, Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 10.1177/1350650117712881, 231, 9, 1160-1170, 2017.09, With recent progress of material technologies, the wear resistance of ultra-high molecular weight polyethylene for total joint prostheses has been improved, but under severe conditions friction and wear problems have not yet been completely solved. Therefore, the application of artificial hydrogel cartilage with similar properties to natural articular cartilage is expected to solve the friction and wear problems by improvement of lubrication mechanism with superior tribological functions. In this study, reciprocating tests of four kinds of poly(vinyl alcohol) hydrogels were carried out and the biphasic finite element analysis was conducted. As artificial cartilage specimens, four kinds of poly(vinyl alcohol) hydrogels were prepared using the repeated freeze-thawing (FT) method, the cast-drying (CD) method and the hybrid method with different layered structure as FT on CD or CD on FT. In reciprocating test of ellipsoidal poly(vinyl alcohol) hydrogel specimen against flat glass plate in saline solution, four kinds of hydrogels exhibited very different frictional levels as hybrid (CD on FT) |
| 26. |
D. Nečas, Yoshinori Sawae, T. Fujisawa, Kazuhiro Nakashima, Takehiro Morita, Tetsuo Yamaguchi, M. Vrbka, I. Křupka, M. Hartl, The Influence of Proteins and Speed on Friction and Adsorption of Metal/UHMWPE Contact Pair, Biotribology, 10.1016/j.biotri.2017.03.003, 11, 51-59, 2017.09, It was reported in several studies that friction and wear of joint prosthesis are apparently influenced by the proteins contained in the synovial fluid. However, detailed mechanisms of these tribological processes have not been clarified yet. The present study aims on the effect of adsorbed protein film on frictional behaviour of metal/polyethylene contact pair. Reciprocating pin-on-plate test was conducted, while the CoCrMo pin was sliding against UHMWPE plate. The contact was lubricated by various solutions of albumin and γ-globulin solved in PBS. After the friction test, the thickness of adsorbed film was evaluated using spectroscopic ellipsometry. Structure of the adsorbed proteins was later examined by FT-IR. The results showed that at low sliding speed equal to 10 mm/s, there was a linear correlation between the friction coefficient and the thickness of the adsorbed protein film. An increase of friction was thus accompanied by the evolution of protein film. In that case, both proteins undergone substantial conformational changes, losing their original structure. On the contrary, proteins could sustain their secondary structure to some extent at higher sliding speed (50 mm/s), when different behaviour of the both proteins could be observed. This phenomenon was attributed to different structure of albumin and γ-globulin in its native state. It might be concluded that friction coefficient of metal-on-polyethylene joint prosthesis is influenced by protein content, as well as kinematic conditions, since the sliding conditions have a certain effect on both the adsorbed film formation and structure of the adsorbed molecules.. |
| 27. |
Keisuke Fukuda, Yoshifumi Shigyo, Hideaki Ariura, Seiji Omata, Takehiro Morita, Tetsuo Yamaguchi, Yoshinori Sawae, Relationship between dynamic stress field and ECM production in regenerated cartilage tissue, 27th International Symposium on Micro-NanoMechatronics and Human Science, MHS 2016
2016 International Symposium on Micro-NanoMechatronics and Human Science, MHS 2016, 10.1109/MHS.2016.7824183, 2017.01, Mechanical stresses exerted in articular cartilage during daily joint movements can stimulate the metabolism of chondrocytes in cartilage. Upregulative effects of mechanical stimuli on extracellular matrix (ECM) biosynthesis of chondrocytes have been utilized in the cartilage tissue for regenerative tissue engineering. However, dynamic functionalities of these regenerated cartilages were lacked compared with the natural arthrodial cartilage. Natural synovial joint surfaces are contacting and sliding each other. As a result, the loading condition applied to the cartilage tissue is not simple. Under the contact between surfaces, non-uniform stress distribution is exerted in the cartilage tissue. The shear stress at contact area is highly depended on the distance from the surface. Moreover, the surface region is exposed to larger shear stress compared with the deep region. We hypothesized that high stress in surface region may stimulate chondrocytes selectively and establish anisotropic structure in elaborated tissue. In this study, the relative motion between cartilage surfaces in a synovial joint is simulated by the rolling-sliding motion of the roller on the cultured chondrocyte-agarose construct. Then, we investigated effects on the ECM distribution and morphology of regenerated cartilage tissue.. |
| 28. |
Yoshinori Sawae, Biotribology in resin material for artificial joint, Toraibarojisuto/Journal of Japanese Society of Tribologists, 62, 7, 435-441, 2017.01. |
| 29. |
Tetsuo Yamaguchi, Yoshinori Sawae, Shmuel M. Rubinstein, Effects of loading angles on stick–slip dynamics of soft sliders, Extreme Mechanics Letters, 10.1016/j.eml.2016.09.008, 9, 2, 331-335, 2016.12. |
| 30. |
Dipankar Choudhury, Juergen M Lackner, Lukasz Major, Takehiro Morita, Yoshinori Sawae, Azuddin Bin Mamat, Ian Stavness, Chanchal K Roy, Ivan Krupka, Improved wear resistance of functional diamond like carbon coated Ti-6Al-4V alloys in an edge loading conditions, JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS, 10.1016/j.jmbbm.2016.04.004, 59, 586-595, 2016.06. |
| 31. |
Changhee Cho, Teruo Murakami, Yoshinori Sawae, Influence of elastic recovery of machining surface asperities on the contact stress and plastic strain of polyethylene tibial insert in virgin knee prosthesis, Tribology Online, 10.2474/trol.11.320, 11, 2, 320-325, 2016.04. |
| 32. |
Nobuo Sakai, C. Hashimoto, Seido Yarimitsu, Yoshinori Sawae, M. Komori, Teruo Murakami, A functional effect of the superficial mechanical properties of articular cartilage as a load bearing system in a sliding condition, Biosurface and Biotribology, 2016.03. |
| 33. |
Dipankar Choudhury, Takehiro Morita, Yoshinori Sawae, Juergen M. Lackner, Mark Towler, Ivan Krupka, A novel functional layered diamond like carbon coating for orthopedics applications, DIAMOND AND RELATED MATERIALS, 10.1016/j.diamond.2015.11.011, 61, 56-69, 2016.01. |
| 34. |
Teruo Murakami, Seido Yarimitsu, Kazuhiro Nakashima, Nobuo Sakai, Yoshinori Sawae, Tetsuo Yamaguchi, Atsushi Suzuki, Biphasic and boundary lubrication mechanisms in artificial hydrogel cartilage: A review, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART H-JOURNAL OF ENGINEERING IN MEDICINE, 10.1177/0954411915611160, 229, 12, 864-878, 2015.12. |
| 35. |
Lei Zhang, Yoshinori Sawae, Teruo Murakami, Hong Yang, Ken Yuki, Investigation of wear and wear particles from shelf-aged crosslinked UHMWPE under
different contact pressures, Triboloby Online, 10.2474/trol.10.404, 10, 6, 404-412, 2015.12. |
| 36. |
Teruo Murakami, Nobuo Sakai, Tetsuo Yamaguchi, Seido Yarimitsu, Kazuhiro Nakashima, Yoshinori Sawae, Atsushi Suzuki, Evaluation of a superior lubrication mechanism with biphasic hydrogels for artificial cartilage, TRIBOLOGY INTERNATIONAL, 10.1016/j.triboint.2014.12.013, 89, 19-26, 2015.09. |
| 37. |
Lei Zhang, Yoshinori Sawae, Tetsuo Yamaguchi, Teruo Murakami, Hong Yang, Effect of radiation dose on depth-dependent oxidation and wear of shelf-aged gamma-irradiated ultra-high molecular weight polyethylene (UHMWPE), TRIBOLOGY INTERNATIONAL, 10.1016/j.triboint.2014.12.011, 89, 78-85, 2015.09. |
| 38. |
Omata Seiji, Yoshinori Sawae, Teruo Murakami, Effect of poly(vinyl alcohol) (PVA) wear particles generated in water lubricant on immune response of macrophage, Biosurface and Biotribology, 10.1016/j.bsbt.2015.02.003, 1, 71-79, 2015.03, To develop a novel biotribological material for artificial cartilage implant with a lubricity supplement of the joint surface, we focused on two
types of poly(vinyl alcohol) (PVA) hydrogel: repeated freeze–thawing (PVA-FT) and cast-drying (PVA-CD) gels. Here we observed the
morphology of wear particles generated during a reciprocating wear test and assessed macrophage immune responses by applying hydrogel wear
particles. As a result, PVA-CD had a significantly lower total amount of wear than did PVA-FT. The size distributions of PVA-FT and -CD wear
particles were similar. Most of the particles were nanoparticles up to approximately 50 nm in diameter. Considering the particle volume
distribution, there were very few micron- and submicron-sized wear particles around 1 μm in diameter. In SEM observations of dried PVA wear
particles, both distributions of wear particles of PVA-FT and -CD were similar. Micron-sized wear particles were chiefly formed by close packing
of 20- to 50-nm-sized particles. Biochemical and immunological evaluations revealed no cytotoxic effects of wear particles on macrophages.
Cytokine synthesis of both wear particle-stimulated groups was significantly lower than that of the lipopolysaccharide-stimulated positive control.
Therefore, it is suggested that PVA wear particles do not affect the macrophage immune response.. |
| 39. |
Lei Zhang, Yoshinori Sawae, Tetsuo Yamaguchi, Teruo Murakami, Hong Yang, Investigation on oxidation of shelf-aged crosslinked Ultra-High Molecular Weight Polyethylene (UHMWPE) and its effects on wear characteristics, Tribology Online, 10, 1, 1-10, 2015.01. |
| 40. |
Nobuo Sakai, Yuichiro Hagihara, Chie Hashimoto, Mochimitsu Komori, Yoshinori Sawae, Teruo Murakami, An estimation of mechanical propertes of articular cartilage for biphasic finite element analyses, Journal of Biomechanical Science and Engineering, 10.1299/jbse.15-00228, 10, 4, 2015.01, The purpose of this study is to estimate material properties of articular cartilage by curve fitting method using finite element (FE) analysis. While various material tests have been conducted to predict the behavior of articular cartilage, one of the recent interests was the accurate estimation of material properties under physiological and dynamic condition. In this study, cylindrical indentation was experimentally conducted in high compressive amount and high compression rate in considering the physiological condition. Each single specimen was sequentially exposed to compressive tests at definite deflection with different compressive amount and different compression rates and compressive creep test. The time-dependent compressive force given by a precise compression tester was utilized for estimation of material properties by curve fitting method with FE analysis. Five typical material properties, which represented total apparent Young's modulus, strain dependent permeability and fibril reinforcement by collagen network, were selected for the estimation process with depth-dependency of Young's modulus. In the curve fitting processes by FE analysis, each material property had specific roles on reproducing experimental time-dependent reactional force. A single material property set estimated in this study successfully reproduced the four different experimental time-dependent behaviors.. |
| 41. |
Kazuhiro Nakashima, Yoshinori Sawae, Teruo Murakami, Stefano Mischler, Behavior of adsorbed albumin film on CoCrMo alloy under in-situ observation, Tribology Online, 10.2474/trol.10.183, 10, 2, 183-189, 2015.01, The protein film adsorbed on joint prosthesis material affects tribological property. It is expected that optimum protein film structure could improve friction and wear of joint prosthesis materials. Therefore, it is important to understand and to clarify the effect of protein film on tribological property. In the rubbing combination of ultra-high molecular weight polyethylene (UHMWPE) and CoCrMo alloy, the adsorption behavior of bovine serum albumin (BSA) and its effect on frictional property during friction were investigated by using electrochemical method. Friction force and electric potential were measured under open circuit potential (OCP) condition, but friction force and electric current were measured under -0.2 V applied potential condition. Under OCP condition, adsorbed BSA was peeled off at first rubbing, after that BSA re-adsorbed on surface under shear force condition. BSA adsorbed film reconstructed by shear force was sustained during rubbing. It is considered that the conformation of adsorbed BSA under shear stress was changed from that of static adsorption, because readsorbed BSA molecule did not show exfoliation from metal surface, which means that adsorption strength was increased from static adsorption. Under applied potential condition where wear performance of BSA film is expected to be evaluated, BSA showed the desorption at first rubbing, and gradual decrease in desorption amount. Therefore, it is confirmed that BSA film on metal surface under rubbing condition is reconstructed during rubbing. The adsorbed film formed during rubbing is stable and has an optimally-adapted structure for shear force and can sustain its property during rubbing.. |
| 42. |
Teruo Murakami, Seido Yarimitsu, Kazuhiro Nakashima, Tetsuo Yamaguchi, Yoshinori Sawae, Nobuo Sakai, Atsushi Suzuki, Superior lubricity in articular cartilage and artificial hydrogel cartilage, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY, 10.1177/1350650114530273, 228, 10, 1099-1111, 2014.10. |
| 43. |
Seido Yarimitsu, Kazuhiro Nakashima, Yoshinori Sawae, Teruo Murakami, Influence of phospholipid and protein constituents on tribological properties of artificial hydrogel cartilage material, Journal of Biomechanical Science and Engineering, 10.1299/jbse.8.257, 8, 3, 257-267, 2013.10, In this study, the influence of phospholipid and protein constituents on friction and wear behavior of artificial hydrogel cartilage was investigated. A sliding pair of an ellipsoidal specimen of poly (vinyl alcohol) (PVA) hydrogel and a flat specimen of PVA hydrogel was evaluated in simplified reciprocating friction test. Dipalmitoylphosphatidylcholine (DPPC) was selected as a phospholipid constituent and was dispersed in saline as liposome. Fluorescent-labeled albumin and γ-globulin were used as protein constituents in lubricants at concentration of 0.7 wt%. After reciprocating friction test, the boundary film formed on the surface of PVA hydrogel and the worn surface of PVA hydrogel were observed by using fluorescent microscope and confocal laser scanning microscope, respectively. When only albumin or γ-globulin was added to lubricant, adhesive wear pattern was frequently observed and large breaking-offof surface structure of PVA hydrogel occurred. Lubricants that contain both proteins and 0.01wt% DPPC showed reduction of friction and suppression of large breaking-offof surface structure of PVA hydrogel. Meanwhile, under coexistence of protein and 0.02wt% DPPC, friction increased compared to that for lubricants that contain 0.01wt% DPPC and the adhesive wear patterns became obvious. Therefore, both the concentration and the relative ratio of proteins to phospholipids are important factors to function adequately as excellent boundary lubricant for PVA hydrogel.. |
| 44. |
Teruo Murakami, Seido Yarimitsu, Kazuhiro Nakashima, Yoshinori Sawae, Nobuo Sakai, Influence of synovia constituents on tribological behaviors of articular cartilage, Friction, 10.1007/s40544-013-0010-6, 1, 2, 150-162, 2013.06, The extremely low friction and minimal wear in natural synovial joints appear to be established by effective lubrication mechanisms based on appropriate combination of articular cartilage and synovial fluid. The complex structure of cartilage composed of collagen and proteoglycan with high water content contributes to high load-carrying capacity as biphasic materials and the various constituents of synovial fluid play important roles in various lubrication mechanisms. However, the detailed differences in functions of the intact and damaged cartilage tissues, and the interaction or synergistic action of synovia constituents with articular cartilage have not yet been clarified. In this study, to examine the roles of synovia constituents and the importance of cartilage surface conditions, the changes in friction were observed in the reciprocating tests of intact and damaged articular cartilage specimens against glass plate lubricated with lubricants containing phospholipid, protein and/or hyaluronic acid as main constituents in synovial fluid. The effectiveness of lubricant constituents and the influence of cartilage surface conditions on friction are discussed. In addition, the protectiveness by synovia constituents for intact articular cartilage surfaces is evaluated.. |
| 45. |
Seido Yarimitsu, Kazuhiro Nakashima, Yoshinori Sawae, Teruo Murakami, Influence of phospholipid and protein constituents on tribological properties of artificial hydrogel cartilage material, Journal of Biomechanical Science and Engineering, 8, 3, 257-267, 2013.05. |
| 46. |
Daisuke Esaki, Yasuyuki Matsushita, Yasunori AYUKAWA, NOBUO SAKAI, Yoshinori Sawae, kiyoshi koyano, Relationship between magnitude of immediate loading and peri-implant osteogenesis in dogs, 10.1111/j.1600-0501.2011.02305.x, 23, 11, 1290-1296, 2012.11. |
| 47. |
Omata Seiji, Shogo Sonokawa, Yoshinori Sawae, Teruo Murakami, Effects of both vitamin C and mechanical stimulation on improving the mechanical characteristics of regenerated cartilage, 10.1016/j.bbrc.2012.07.019, 424, 4, 724-729, 2012.08. |
| 48. |
Changhee Cho, Teruo Murakami, Yoshinori Sawae, Wear phenomena of ultra-high molecular weight polyethylene (UHMWPE) joints, Wear of Orthopaedic Implants and Artificial Joints, 10.1016/B978-0-85709-128-4.50008-X, 221-245, 2012.04, This chapter discusses wear phenomena of ultra-high molecular weight polyethylene (UHMWPE) in artificial joints. The importance of wear in artificial joints, lubrication modes in artificial joints as UHMWPE-on-hard and improving methods for wear reduction of UHMWPE are reviewed. Wear phenomena of UHMWPE artificial knee joints are discussed with reference to the wear characteristics of retrieved artificial knee joints, together with an experimental study on the delamination mechanism of UHMWPE, macroscopic contact analysis between the femoral component and tibial insert, and microscopic contact analysis between surface asperities and tibial inserts.. |
| 49. |
NOBUO SAKAI, Yuichiro Hagihara, Tsukasa Furusawa, Natsuko Hosoda, Yoshinori Sawae, Teruo Murakami, Analysis of biphasic lubrication of articular cartilage loaded by cylindrical indenter, 10.1016/j.triboint.2011.03.016, 46, 2, 225-236, 2012.02. |
| 50. |
T. Murakami, K. Nakashima, S. Yarimitsu, Y. Sawae, N. Sakai, Effectiveness of adsorbed film and gel layer in hydration lubrication as adaptive multimode lubrication mechanism for articular cartilage, Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 10.1177/1350650111415756, 225, 12, 1174-1185, 2011.12, With various daily activities, the effectiveness of adsorbed film formed on a gel-like layer at the uppermost superficial articular cartilage in natural synovial joints becomes important to control the friction and wear of articular cartilage in mixed or boundary lubrication regime as an adaptive multimode lubrication mechanism. Furthermore, in the case where the adsorbed film has been removed, the proteoglycan gel layer is expected to preserve low friction and protect against the wear of bulk cartilage tissue with an effective hydration lubrication mechanism. Besides, it is indicated that the biphasic lubrication plays an important role in lowering of friction in articular cartilage containing a large amount of water. At the present stage, however, the detailed relationship between adsorbed films and hydrated gel layers has not yet been elucidated. In this article, the frictional behaviours of articular cartilage on a glass plate were observed in the reciprocating tests with the restarting process after interruption and unloading. The lubricating effectiveness of adsorbed films in hyaluronate (HA) solutions was examined using intact and partially damaged cartilage specimens. The role of albumin and g-globulin in relation to the surface conditions of gel layer is discussed. The restarting friction immediately after reloading became lower as a result of recovery of the effective interstitial fluid pressurization and hydration and adsorbed films have a significant effect on the frictional behaviour at local contacts. To clarify the molecular phenomena taking place under rubbing condition, in situ observations of the forming adsorbed film were conducted. The measurements were performed using the fluorescent staining method for protein and HA molecules at low contact pressures.. |
| 51. |
Takehiro Morita, F. Sato, Yoshinori Sawae, Joichi Sugimura, Effects of metal counter surfaces on friction and wear of polymeric seal materials in hydrogen, 21st International Conference on Fluid Sealing
BHR Group - 21st International Conference on Fluid Sealing, 167-178, 2011.12, This paper describes dry reciprocating sliding tests of polymers against some metallic materials in gaseous hydrogen. The polymers tested included PTFE, PTFE composites, PVDF and UHMWPE, while the metallic counterfaces included hardened bearing steel, austenitic stainless steel and cobalt-based alloy. The sliding tests revealed that friction and wear depended on the counterface materials, and that the initial running-in wear influenced the subsequent steady state friction and wear. XPS analysis showed that friction and wear of the four fluorine containing polymers depended on the formation of metal fluoride on the metallic counterface.. |
| 52. |
Contact Analysis between Microscopic Surface Asperity of a Virgin Femoral Component and Ultra-High Molecular Weight Polyethylene. |
| 53. |
Seiji OMATA, Yoshinori SAWAE, Teruo MURAKAMI, Influence of Ascorbic acid (AsA) Concentration in Culture Medium on Mechanical Property of Regenerated Cartilage, Journal of Environment and Engineering, 6, 416-425, 2011.03. |
| 54. |
Natsuko Hosoda, Nobuo SAKAI, Yoshinori SAWAE and Teruo MURAKAMI, Finite Element Analyses of Articular Cartilage Models Considering Depth-Dependent Elastic Modulus and Collagen Fiber Network, Journal of Biomechanical Science and Engineering, 5, 4, 437-448, 2010.10. |
| 55. |
Y. Sawae, K. Fukuda, E. Miyakoshi, S. Doi, H. Watanabe, K. Nakashima, J. Sugimura, Tribological Characterization of Polymeric Sealing Materials in High Pressure Hydrogen Gas, Proceedings of the STLE/ASME 2010 International Joint Tribology Conference, IJTC2010-41238, 2010.10. |
| 56. |
Influence of phospholipid bilayer on frictional behavior of artificial articular cartilage material. |
| 57. |
S. Omata, T. Shimizi, Y. Sawae, T. Murakami, Effect of vitamin C on mechanical property of the regenerated-cartilage tissue, IFMBE Proceedings, 31, 899-902, 2010.08. |
| 58. |
S. Yarimitsu, K. Nakashima, Y. Sawae and T. Murakami, The Role of Subchondral Tissues on Lubrication Properties of Natural Articular Cartilage, IFMBE Proceedings, 31, 911-914, 2010.08. |
| 59. |
K. Nakashima, Y. Sawae, N. Tsukamoto, H. Miura, Y. Iwamoto, T. Murakami, Wear behaviour of an artificial cartilage material for hemiarthroplasty, IFMBE Proceedings, 31, 1169-1172, 2010.08. |
| 60. |
Influence of synovia constituents on frictional behavior of artificial cartilage material and formation of boundary lubricating film. |
| 61. |
C. Morillo, Y. Sawae and T. Murakami, Effect of bovine serum constituents on the surface of the tribological pair alumina/alumina nanocomposites for total hip replacement, Tribology International, 43, 5月6日, 1158-1162, 2010.05. |
| 62. |
C.H. Cho, T. Murakami and Y. Sawae, Influence of microscopic surface asperities on the wear of ultra-high molecular weight polyethylene in a knee prosthesis, Proc. Instn Mech. Engrs Part H, 224, 515-529, 2010.04. |
| 63. |
K. Nakashima, A. Yamaguchi, Y. Kurono, Y. Sawae, T. Murakami and J. Sugimura, Effect of high-pressure hydrogen exposure on wear of polytetrafluoroethylene sliding against stainless steel, Proc. Instn Mech. Engrs Part J, 224, 285-292, 2010.01. |
| 64. |
Seido Yarimitsu, Kazuhiro Nakashima, Yoshinori Sawae and Teruo Murakami,, Influences of Lubricant Composition on Forming Boundary Film Composed of Synovia Constituents, Tribology International, 42, 11月12日, 1615-1625, 2009.11. |
| 65. |
Yoshinori SAWAE, Kazuhiro NAKASHIMA, Shunichiro DOI, Teruo MURAKAMI and Joichi SUGIMURA, Effects of High Pressure Hydrogen on Wear of PTFE and PTFE Composite, Proceedings of the ASME/STLE 2009 International Joint Tribology Conference, 2009.10. |
| 66. |
S. Sakai, S. Ito, Y. Ogushi, I. Hashimoto, N. Hosoda, Y. Sawae and K. Kawakami, Enzymatically fabricated and degradable microcapsules for production of multicellular spheroids with well-defined diameters of less than 150 μm, Biomaterials, 30, 30, 5937-5942, 2009.10. |
| 67. |
Yoshinori SAWAE, Daichi YAMAMOTO, Kazuhiro NAKASHIMA, Shunichiro DOI, Teruo MURAKAMI and Joich SUGIMURA, Wear Characteristics of PTFE and PTFE Based Composites in Gaseous Hydrogen, Proceedings of World Tribology Congress 2009, 18, 2009.09. |
| 68. |
Teruo MURAKAMI, Yoshinori SAWAE, Kazuhiro NAKASHIMA, Nobuo SAKAI and Seido YARIMITSU, Importance of Materials and Lubricants on Tribological Properties in Joint Prostheses in Comparison with Natural Synovial Joints, Proceedings of World Tribology Congress 2009, 74, 2009.09. |
| 69. |
Changhee CHO, Teruo MURAKAMI and Yoshinori SAWAE, Influence of Microscopic Surface Topography on the Wear Phenomenon in Knee Prosthesis, Proceedings of World Tribology Congress 2009, 648, 2009.09. |
| 70. |
Kazuhiro NAKASHIMA, Yoshie KURONO, Yoshinori SAWAE, Teruo MURAKAMI and Joichi SUGIMURA, Effect of Moisture Content on Wear of PTFE in Hydrogen, Proceedings of World Tribology Congress 2009, 658, 2009.09. |
| 71. |
Yoshinori SAWAE, Takayuki SARUWATARI, Seido YARIMITSU and Teruo MURAKAMI, Effects of Lubricant Lipid Concentration on Wear Rate of UHMWPE and Characteristics of Wear Particles in Multidirectional Sliding Wear Test, Proceedings of World Tribology Congress 2009, 888, 2009.09. |
| 72. |
S. Omata, Y. Sawae and T. Murakami, Influence of Ascorbic acid(AsA) concentration in culture medium on mechanical property of regenerated cartilage, Proceedings of World Congress on Medical Physics and Biomedical Engineering, 25, 2009.09. |
| 73. |
Hiroyoshi TANAKA, Yoshinori SAWAE, Kanao FUKUDA, Shigemasa YAMAGAMI, Takehiro MORITA, Naoshi IZUMI and Joich SUGIMURA, New Experiment System for Sliding Tests in Hydrogen and Surface Analysis with Transfer Vessel, Tribology Online, 4, 4, 82-87, 2009.07. |
| 74. |
Teruo MURAKAMI, Kazuhiro NAKASHIMA, Yoshinori SAWAE, Nobuo SAKAI and Natsuko HOSODA, Roles of adsorbed film and gel layer in hydration lubrication for articular cartilage, Proc. IMechE Part J: J. Engineering Tribology, 223, 287-295, 2009.05. |
| 75. |
Yu MORIWAKI, Nobuo SAKAI, Yoshinori SAWAE and Teruo MURAKAMI, Development of Forearm Models Based on Human Musculoskeletal System, Journal of Biomechanical Science and Engineering, 4, 1, 153-164, 2009.04. |
| 76. |
Teruo MURAKAMI, Kazuhiro NAKASHIMA, Yoshinori SAWAE, Nobuo SAKAI, Seido YARIMITSU and Natsuko HOSODA, Roles of adsorbed film and gel layer in hydration lubrication in natural synovial joints, Abstract. 4th Asian Pacific Conference on Biomechanics, 178-179, 2009.04. |
| 77. |
Carlos MORILLO, Yoshinori SAWAE and Teruo MURAKAMI, Effect of Proteins on the Surface of the Tribological Pair Alumina/Alumina Nanocomposites for Total Hip Replacement, Extended Abstracts of 2nd International Conference on Advanced Tribology 2008, pp.59-61, 2008.12. |
| 78. |
Yoshinori SAWAE, Kazuhiro NAKASHIMA, Akira YAMAGUCHI, Shunichiro DOI, Hiroyoshi TANAKA, Shigemasa YAMAGAMI, Yoshie KURONO, Teruo MURAKAMI, and Joich SUGIMURA, Transfer Film Formation and Wear of PTFE in Gaseous Hydrogen, Extended Abstracts of 2nd International Conference on Advanced Tribology 2008, pp.115-117, 2008.12. |
| 79. |
Natsuko HOSODA, Nobuo SAKAI, Yoshinori SAWAE, Teruo MURAKAMI, Finite Element Analysis of Articular Cartilage Model Considering the Configuration and Biphasic Property of the Tissue, Proceedings of The 13th International Conference on BIOMEDICAL ENGINEERING 2008, On CD-ROM, 2008.12. |
| 80. |
Tribology for Functional Tissue Engineering of Articular Cartilage. |
| 81. |
Influence of Microscopic Surface Asperity of Metallic Femoral Component on the Wear of Ultra-high Molecular Weight Polyethylene Tibial Insert. |
| 82. |
Yoshinori SAWAE, Akira YAMAGUCHI, Kazuhiro NAKASHIMA, Teruo MURAKAMI and Joichi SUGIMURA, Wear Behavior of Polymeric Sealing Material in Gaseous Hydrogen, Proceedings of STLE/ASME International Joint Tribology Conference, IJTC2008-71225, 2008.10. |
| 83. |
Carlos MORILLO, Yoshinori SAWAE and Teruo MURAKAMI, Tribological Analysis of Alumina Nanocomposites for Orthopedics Applications, Proceedings of STLE/ASME International Joint Tribology Conference, IJTC2008-71155, 2008.10. |
| 84. |
Seiji OMATA, Yoshinori SAWAE and Teruo MURAKAMI, The Influence of Mechanical Stimulation on the Development of Tissue-Engineered Cartilage, Proceedings of KAIST-Kyushu University Joint Seminar 2008, p.22, 2008.09. |
| 85. |
Carlos MORILLO, Yoshinori SAWAE and Teruo MURAKAMI, Tribological Characteristics of Al2O3 Nanocomposites for Joint Prostheses, Journal of Biomechanical Science and Engineering, Vol.3, No.3, pp.209-220, 2008.09. |
| 86. |
Seido YARIMITSU, Kazuhiro NAKASHIMA, Yoshinori SAWAE and Teruo MURAKAMI, Effects of Lubricant Composition on Adsorption Behavior of Proteins on Rubbing Surface and Stability of Protein Boundary Film, Tribology Online, Vol.3, No.4, pp.238-242, 2008.08. |
| 87. |
Yoshinori Sawae, Akio Yamamoto, Teruo Murakami, Influence of protein and lipid concentration of the test lubricant on the wear of ultra high molecular weight polyethylene, Tribology International, Vol.41, pp.648-656, 2008.07. |
| 88. |
Natsuko HOSODA, Nobuo SAKAI, Yoshinori SAWAE, Teruo MURAKAMI, Depth-Dependence and Time-Dependence in Mechanical Behaviors of Articular Cartilage in Unconfined Compression Test under Constant Total Deformation, Journal of Biomechanical Science and Engineering, Vol.3, No.2, pp.209-220, 2008.07. |
| 89. |
Hironobu KOSEKI, Hiroyuki SHINDO, Koumei BABA, Takamasa FUJIKAWA, Nobuo SAKAI, Yoshinori SAWAE, Teruo MURAKAMI, Surface-engineered metal-on-metal bearings improve the friction and wear properties of local area contact in total joint arthroplasty, Surface & Coatings Technology, Vol.202, No.19, pp.47754779, 2008.06. |
| 90. |
Seido YARIMITSU, Kazuhiro NAKASHIMA, Yoshinori SAWAE, Teruo MURAKAMI, Study on the Mechanisms of Wear Reduction of Artificial Cartilage through in situ Observation on Forming Protein Boundary Film, Tribology Online, Vol. 2, No. 4, 114-119, 2007.12. |
| 91. |
Teruo MURAKAMI, Kazuhiro NAKASHIMA, Yoshinori SAWAE, Roles of Adsorbed Film in Hydration Lubrication for Articular Cartilage, Journal of Biomechanical Science and Engineering, Vol.2, Suppl. 1, p.7, 2007.11. |
| 92. |
Natsuko HOSODA, Nobuo SAKAI, Yoshinori SAWAE, Teruo MURAKAMI, Finite Element Analysis of Cartilage Considering the Depth Dependence and Time Dependence of Young’s modulus under Constant Total Compressive Deformation, Journal of Biomechanical Science and Engineering, Vol.2, Suppl. 1, p.79, 2007.11. |
| 93. |
Yu MORIWAKI, Nobuo SAKAI, Yoshinori SAWAE, Teruo MURAKAMI, Development of an Arm Model with a Bionic Elbow Joint, Journal of Biomechanical Science and Engineering, Vol.2, Suppl. 1, p.112, 2007.11. |
| 94. |
Nobuo SAKAI, Katsuki HAYASHI, Shunsuke YAMAGUCHI, Eiichi FUKAHORI, Shihoko SHIMIZU, Akiomi KOGA, Yoshinori SAWAE, Teruo MURAKAMI, The Development of Shoulder Motor Orthosis for Stroke Rehabilitation, Journal of Biomechanical Science and Engineering, Vol.2, Suppl. 1, p.191, 2007.11. |
| 95. |
Carlos MORILLO, Yoshinori SAWAE, Teruo MURAKAMI, Surface Analysis of the Tribological Pair Al2O3 Nanocomposites and Al2O3 in Different Media, Journal of Biomechanical Science and Engineering, Vol.2, Suppl. 1, p.208, 2007.11. |
| 96. |
Kazuhiro NAKASHIMA, Yoshinori SAWAE, Teruo MURAKAMI, Effect of the conformational changes and differences of proteins on the frictional properties of Poly (vinyl alcohol) Hydrogel, Tribology International, Vol.40, pp.1423-1427, 2007.10. |
| 97. |
Yoshinori SAWAE, Akira YAMAGUCHI, Kazuhiro NAKASHIMA, Teruo MURAKAMI, Joichi SUGIMURA, Effects of Hydrogen Atmosphere on Wear Behavior of PTFE Sliding Against Austenitic Stainless Steel, Proceedings of ASME/STLE International Joint Tribology Conference, IJTC2007-44285, 2007.10. |
| 98. |
Yoshinori SAWAE, Akio YAMAMOTO, Teruo MURAKAMI, Accelerated Wear of UHMWPE for Joint Prosthesis in Physiological Solutions Containing Protein and Lipid, Proceedings of EUROCORR 2007, On CD-ROM, 2007.09. |
| 99. |
Kazuhiro NAKASHIMA, Naohiro TAKAMURA, Yosinori SAWAE, Teruo MURAKAMI, Mechanisms of Protein Boundary Film Formation for Poly (vinyl alcohol) Hydrogel as Artificial Cartilage Material, Proceedings of International Conference on Advanced Technology in Experimental Mechanics 2007, On CD-ROM, 2007.09. |
| 100. |
Seido YARIMITSU, Kazuhiro NAKASHIMA, Yoshinori SAWAE, Teruo MURAKAMI, In Situ Observation of Forming Boundary Film Composed of Synovia Constituents on Rubbing Surface of Artificial Cartilage Material, Proceedings of International Conference on Advanced Technology in Experimental Mechanics 2007, On CD-ROM, 2007.09. |
| 101. |
Yoshinori SAWAE, Jun HONDA, Emiko SUZUKI, Yasuyuki MORITA, Masao WATANABE, Toshiyuki SANADA, Teruo MURAKAMI, Experimental Characterization of Regenerated Cartilage Model Cultured under Cyclic Compression, Proceedings of International Conference on Advanced Technology in Experimental Mechanics 2007, On CD-ROM, 2007.09. |
| 102. |
Yoshinori SAWAE, Tatsuro IKEGAMI, Yasuyuki MATSUSHITA, Nobuo SAKAI, Kiyoshi KOYANO, Teruo MURAKAMI, Cyclic Loading Test of Dental Implant with Mastication Simulator, Proceedings of International Conference on Advanced Technology in Experimental Mechanics 2007, On CD-ROM, 2007.09. |
| 103. |
Y. Kitajima, S. Sugino, Toshiyuki Sanada, Yoshinori SAWAE, Teruo MURAKAMI, Masao WATANABE, Transport phenomena in engineered cartilage with tissue development in agarose gel, Proceedings of the 5th Joint ASME/JSME Fluids Engineering Conference, FEDSM2007-37465, 2007.07. |
| 104. |
Kazuhiro NAKASHIMA, Yoshinori SAWAE, Teruo MURAKAMI, Influence of protein conformation on frictional properties of poly (vinyl alcohol) hydrogel for artificial cartilage, Tribology Letters, Vol.26, pp.145-151, 2007.05. |
| 105. |
Teruo MURAKAMI, Yoshinori SAWAE, Kazuhiro NAKASHIMA, Seido YARIMITSU, Tsutomu SATO, Micro- and Nanoscopic Biotribological Behaviours in Natural Synovial Joints and Artificial Joints, Proceedings of the Institution of Mechanical Engineers, Part J, Journal of Engineering Tribology, Vol.221, No.3, 237-245, 2007.05. |
| 106. |
Carlos MORILLO, Yoshinori SAWAE, SW LEE, J Lira OLIVARSE, Teruo MURAKAMI, Tribological Analysis of Al2O3 Nanocomposites as an Alternative for Hip Joint Replacement Materials, Proceedings of 16th International Conference on Wear of Materials, On CD-ROM, 2007.04. |
| 107. |
The Development of Elbow Orthosis with Motor Function. |
| 108. |
An Experimental Study on the Delamination Mechanism of UHMWPE for Artificial Joints. |
| 109. |
The Effect of the Mixing Ratio on the Temporary Cement Retention Force and Seating Discrepancy of Cement-retained Implant Superstructures. |
| 110. |
K. Nakashima, Y. Sawae, T. Murakami, Study on Wear Reduction Mechanisms of Artificial Cartilage by Synergistic Protein Boundary Film Formation, JSME International Journal Series C, 10.1299/jsmec.48.555, 48, 4, 555-561, Vol.48, 555-561, 2005.12. |
| 111. |
Y. Sawae, T. Murakami, T. Sawano, The Influences of Lipid and Protein Concentration on Wear of Ultra-High Molecular Weight Polyethylene, Life Cycle Tribology, Ed. D. Dowson et al., 171-177, 2005.11. |
| 112. |
T. Sawano, T. Murakami, Y. Sawae, Evaluation of Wear Resistance of Ultra-High Molecular Weight Polyethylene for Joint Prostheses in the Multi-Directional Pin-on-Plate Tester, Life Cycle Tribology, Ed. D. Dowson et al., 161-169, 2005.10. |
| 113. |
The Development of Micro Testing Machine Equipped with Microscope and Visualization Method for Investigation of Cartilaginous Tissue. |
| 114. |
Noninvasive in vivo Human Capillary Vessel Blood Flow Analysis. |
| 115. |
Mechanical Test of Temporary Cementation for Dental Implant Using a Mastication Simulator. |
| 116. |
An Experimental Study on the Cold Flow of UHMWPE Tibial Insert. |
| 117. |
High Speed Observation of Human Capillary Vessel Loop and Blood Flow Analysis. |
| 118. |
A Study on the Cold Flow of UHMWPE Tibial Insert in Knee Prostheses. |
| 119. |
Effect of Gamma Irradiation on Wear Characteristics of UHMWPE for Joint Prostheses. |
| 120. |
T. MURAKAMI, N. SAKAI, Y. SAWAE, K. TANAKA and M. IHARA, Influence of Proteoglycan on Time-Dependent Mechanical Behaviors of Articular Cartilage under Constant Total Compressive Deformation, JSME International Journal, Series C, 10.1299/jsmec.47.1049, 47, 4, 1049-1055, Vol.47, 1049-1055, 2004.12. |
| 121. |
3-dimensional measurement of range of motion in the shoulder joint in consideration of successive motion. |
| 122. |
Effect of protein boundary films on wear of artificial cartilage (2nd Report). |
| 123. |
Evaluation of Wear Property of PVA Hydrogel as Artificial Cartilage and Effect of Protein Film on Wear-Resistant Property. |
| 124. |
C.H. Cho, T. Murakami, Y. Sawae, N. Sakai, H. Miura, T. Kawano and Y. Iwanoto, Elasto-plastic contact analysis of an ultra-high molecular weight polyethylene tibial component based on geometrical measurement from a retrieved knee prosthesis, Proc. Instn Mech. Engrs, 10.1243/0954411041561018, 218, H4, 251-259, Vol.218 Part H, 251-259, 2004.09. |
| 125. |
Y. Sawae, J. Shelton, D.L. Bader and M.M. Knight, Confocal Analysis of Local and Cellular Strains in Chondrocyte-Agarose Constructs Subjected to Mechanical Shear, Annals of Biomedical Engineering, 10.1023/B:ABME.0000030261.38396.c0, 32, 6, 860-870, Vol.32, 860-870, 2004.06. |
| 126. |
T. Murakami, Y. Sawae and M. Ihara, Protective Mechanism of Articular Cartilage to Severe Loading: Roles of Lubricants, Cartilage Surface Layer, Extracellular Matrix and Chondrocyte, JSME International Journal Series C, 10.1299/jsmec.46.594, 46, 2, 594-603, Vor.46, 594-603, 2003.12. |
| 127. |
The Evaluation of Structual Role of Proteoglycan in Articular Cartilage under Constant Compression. |
| 128. |
Study on Surface Morphology of Human Osteoarthritic Cartilage with Atmic Force Microscopy. |
| 129. |
Finite Element Analysis of Cold Flow in UHMWPE Tibial Component -Influence on Stress Distribution and Wear Behavior-. |
| 130. |
Effect of Protein Adsorbed Films on Wear of Artificial Cartilage. |
| 131. |
Y. Sawae, T. Murakami, T. Sawano, I. Noda and T. Shimotoso, Surface Characteristics and Tribological Behaviour of New Zirconia Ceramics for Cementless Knee Joint Prostheses, Tribological Research and Design for Engineering Systems, 263-271, 263-271, 2003.09. |
| 132. |
Evaluation of Wear Characteristics of Artificial Joint Materials in the Multi-Directional Pin-on-Plate Tester. |
| 133. |
Modelling of Articular Cartilage Containing Chondrocytes and Finite Element Analysis for Articular Cartilage and Chondrocytes Under Compression. |
| 134. |
M. Ihara, T. Murakami and Y, Sawae, Finite Element Analyses for Time-dependent and Depth-dependent Deformation of Articular Cartilage and Chondrocytes Under Constant Compression, Memoirs of the Faculty of Engineering, Vol.62, 165-177, 2002.12. |
| 135. |
Examination of Chondrocytes within Articular Cartilage Using Confocal Laser Scanning Microscopy and Analysis of Stress-Strain Transmission. |
| 136. |
Effect of Protein Ingredient on Friction and Wear of PVA Hydrogel as Artificial Cartilage. |
| 137. |
Elasto-Plastic Contact Analysis on Fatigue Wear Behavior of UHMWPE Tibial Components. |
| 138. |
Contact Analysis of UHMWPE Tibial Component Based on Geometrical Measurement for Retrieved Knee Prosthesis. |
| 139. |
N. Sakai, T. Murakami and Y. Sawae, A Development of Joint mechanism of Robot Arm Based on Human Shoulder Mechanism, Memoirs of the Faculty of Engineering, Vol.61, 123-138, 2001.12. |
| 140. |
Y. Sawae, T. Murakami, K. Matsumoto and M. Horimoto, Study on Morphology and Lubrication of Articular Cartilage Surface With Atomic Force Microscopy, Japanese Journal of Tribology, 45, 2, 150-157, Vol.45, 51-62, 2001.11. |
| 141. |
Y. Sawae, T. Murakami, T Sawano, I. Noda and T. Shimotoso, Quantitative Evaluation of Wear Property of Polyethylene-on-Ceramic Sliding Pairs for Joint Prostheses in Multidirectional Sliding Test, Bioceramics, 218-2, 665-668, Vol.14, 665-668, 2001.10. |
| 142. |
Friction and Wear Properties of PVA Hydrogel. |
| 143. |
Strain Analysis of Articular Cartilage Using Finit Element Method. |
| 144. |
Evaluation of Wear in Retrieved Knee Prostheses. |
| 145. |
Trajectory Analysis of Catching Motion in a Hand Using a Falling Weight and Three Dimensional Position Sensor. |
| 146. |
Plasma Carburized Titanium Alloy as Bearing Surface Material for Joint Prostheses. |
| 147. |
C. Cho, T, Murakami and Y. Sawae, Elasto-Plastic Contact Analysis of Ultra-High Molecular Weight Polyethylene for Artificial Knee Joint using Finite Element Method, Proc. International Tribology Conference Nagasaki, 2000, 1503-1508, 2001.10. |
| 148. |
K. Nakashima, T. Murakami and Y. Sawae, Evaluation of Tribological Properties of Polyvinyl Alcohol Hydrogel as Artificial Cartilage, Proc. International Tribology Conference Nagasaki, 2000, 1537-1540, 2001.10. |
| 149. |
Y. Sawae and T. Murakami, Wear Mechanism of Ultra-high Molecular Weight Polyethylene in Multidirectional Sliding Wear Test, Proc. International Tribology Conference Nagasaki, 2000, 1521-1526, 2001.10. |
| 150. |
C. Cho, T. Murakami, Y. Sawae, H. Miura, T. Kawano and Y. Iwamoto, A Study on the Fatigue Wear of UHMWPE in Artificial Knee Joints, Proc. The 5th International Joint Symposium between Chungnan National Univ. & Kyushu Univ, 49-55, 2001.09. |
| 151. |
Y.Sawae and T. Murakami, Role of Synovia in Wear Mechanism of UHMWPE, Tribology in Biomechanical Systems, Science and Applications, 31-45, 2001.09. |
| 152. |
Y. Sawae, T. Murakami, S. Tashima and T. Shimotoso, Wear Test of Alumina-on-Alumina Sliding Pairs as Model Experiment for Wear in Ceramic-on-Ceramic Joint Prostheses, Tribology Research: From Model Experiment to Industrial Problem, 151-160, 2001.08. |
| 153. |
Surface layer of articular cartilage observed by atomic force microscopy in liqid - Morphology and role in joint lubrication -. |
| 154. |
Y. Sawae and T. Murakami, Effect of Protein and Lipid on Wear of Ultra-High Molecular Weight Polyethylene in Multidirectional Sliding Wear Test, Proc. Biotribology Satellite Forum of ITC Nagasaki, 2000 and 21st Biotribology Symposium, 7月8日, 2000.08. |
| 155. |
C. Cho，T. Murakami，Y. Sawae， H. Miura，T. Kawano，R. Nagamine，K. Urabe，S. Matsuda and Y. Iwamoto, Wear Characteristics of Ultra-High Molecular Weight Polyethylene Components in Retrieved Knee Prostheses, Proc. Biotribology Satellite Forum of ITC Nagasaki, 2000 and 21st Biotribology Symposium, 19-22, 2000.08. |
| 156. |
Y. Sawae, T. Murakami and S. Doi, Worn Surface Characteristics of Ultra-High Molecular Weight PolyethyleneLubricated with Bovine Serum, Thinning Films and Tribological Interfaces, 347-356, 2000.08. |
| 157. |
T. Murakami, Y. Sawae, K. Nakashima and J. Fisher, Tribological Behaviour of Artificial Cartilage in Thin Film Lubrication, Thinning Films and Tribological Interface, 317-327, 2000.08. |
| 158. |
T. Murakami, Y. Sawae, S. Doi, S. Tashima and T. Shimotoso, Wear Reduction by Material Combination and Improvement of Microstructure in Ceramic-on-Ceramic Sliding for Total Joint Replacement, Trans. 6th World Biomaterials Congress Trans, 876, 2000.05. |
| 159. |
Evaluation of in vivo Fixation and Stabilization of Polyvinyl Alcohol Hydrogel for Artificial Cartilage. |
| 160. |
Study on Morphology and Lubrication of Articular Cartilage Surface with Atomic Force Microscopy. |
| 161. |
T. Murakami, Y. Sawae and K. Nakashima, Importance of Lubrication in Total Replacement Joints with Compliant Artificial Cartilage, Trans. 6th World Biomaterials Congress Trans, 1079, 2000.05. |
