||Mechanical design assessment of zirconia abutment supported on titanium base.
||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..
||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..
||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.
||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.
||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.
||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.
||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..
||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.
||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.
||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.
||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.
||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.
||Influence of phospholipid bilayer on frictional behavior of artificial articular cartilage material.
||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.
||Influence of synovia constituents on frictional behavior of artificial cartilage material and formation of boundary lubricating film.
||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.
||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.
||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.
||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.
||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.
||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.
||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.
||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.
||Tribology for Functional Tissue Engineering of Articular Cartilage.
||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.
||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.
||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.
||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.
||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.
||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.
||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.
||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.
||The Effect of the Mixing Ratio on the Temporary Cement Retention Force and Seating Discrepancy of Cement-retained Implant Superstructures.
||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.
||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.
||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.
||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.