To examine the lubrication mechanisms in both natural synovial joints and artificial with cartilages, pendulum tests of pig shoulder simulator sliding pairs a stainless steel spherical component articular cartilage or have been conducted. Firstly, it was shown that concentration hyaluronic acid viscosity adsorbed film formation proteins phospholipids exerted significant effect on frictional behaviour swinging motion immediately after loading 100 N. Under high load 1 kN, low friction observed...

Abstract 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 fluid. complex structure composed collagen proteoglycan with high water content contributes load-carrying capacity as biphasic materials the various constituents fluid play important roles mechanisms. However, detailed differences functions intact damaged tissues, interaction or synergistic action...

Abstract Adaptive modeling and remodeling are controlled by the activities of osteoblasts osteoclasts, which capable sensing their mechanical environments regulating deposition or resorption bone matrix. The effects stimuli on isolated osteoclasts have been scarcely examined because it has proven to be difficult prepare a number pure cultivate them mineralized substratum during stimulation. Recently, we developed an apparatus for applying stretching ivory slice/plastic plate component cells...

In healthy natural synovial joints, the extremely low friction and minimum wear are maintained by their superior load-carrying capacity lubricating ability. This performance appears to be actualized not single lubrication mode but synergistic combination of multimode mechanisms such as fluid film, biphasic, hydration, gel film and/or boundary lubrication. On contrary, in most artificial joints composed ultra-high molecular weight polyethylene against metal or ceramic-mating material, mixed...

Poly (vinyl alcohol) (PVA) hydrogel with high water content is the candidate material for artificial cartilage. PVA hydrogels prepared by freeze-thawing (FT) method (PVA-FT gel), cast-drying (CD) (PVA-CD gel) and hybrid of FT CD (PVA-hybrid were developed their friction wear behaviors evaluated. Sliding pairs a cobalt-chromium-molybdenum alloy or alumina ceramic ball plate tested in reciprocating test. Ultra-pure simulated synovial fluid used as lubricants PVA-FT gel showed severe ultra-pure...

Poly(vinyl alcohol) (PVA) hydrogel is one of the anticipated materials for artificial cartilage. PVA has high water content and a low elastic modulus similar to natural cartilage, but its major disadvantage lower strength. experienced rapid wear under severe conditions such as mixed or boundary lubrication. Therefore, existence protective surface film with friction becomes important prevent failure. In this study, reciprocating frictional tests sliding pair glass plate were carried out,...

Natural joints exhibiting excellent performance under reciprocating slow speed and high loading conditions have a prominent lubrication mechanism as an adaptive multimode lubrieation, where elastohydrodynamic fluid film plays the main role supported by various supplimental mechanisms. In contrast, most of existing joint prostheses operate not but mixed lubrication, which induces some tribological problems such loosening wear. Thus, recent investigations on mechanisms in natural synovial...

To maintain low friction and wear in natural synovial joints, adsorbed film formation on articular cartilage surface appears to play an important role mixed or boundary lubrication regime where local direct contact occurs. Furthermore, the proteoglycan gel layer at uppermost superficial zone preserving by hydration mechanism even after removal of film. However, interaction synergistic action between hydrated film/surface has not yet been clarified. examine roles lubrication, changes were...

With various daily activities, the effectiveness of adsorbed film formed on a gel-like layer at uppermost superficial articular cartilage in natural synovial joints becomes important to control friction and wear mixed or boundary lubrication regime as an adaptive multimode mechanism. Furthermore, case where has been removed, proteoglycan gel is expected preserve low protect against bulk tissue with effective hydration Besides, it indicated that biphasic plays role lowering containing large...

The healthy natural synovial joints maintain excellent load-carrying capacity and lubricating properties with extremely low friction minimum wear even under heavily loaded conditions. superior performance appears to be actualized by not single lubrication mode but the synergistic combination of various modes depending on severity operating This mechanism is called adaptive multimode application this good working artificial soft layer expected contribute remarkable improvement in longevity...

With recent progress of material technologies, the wear resistance ultra-high molecular weight polyethylene for total joint prostheses has been improved, but under severe conditions friction and problems have not yet completely solved. Therefore, application artificial hydrogel cartilage with similar properties to natural articular is expected solve by improvement lubrication mechanism superior tribological functions. In this study, reciprocating tests four kinds poly(vinyl alcohol)...

Repeated four-ball tests of squalane with or without organic sulfides have been carried out to investigate the relationship between properties surface film formed on rubbing surfaces and lubricating performance several sulfides. With dibenzyl disulfide monosulfide, friction was remarkably reduced load-carrying capacity raised in second run additive after first additive, presumably which only an oxide had formed. In contrast, for diphenyl disulfide, repetition tests, each effective. EPMA,...

PVA (poly (vinyl alcohol)) hydrogel is one of the anticipated materials for artificial cartilage. In previous research, authors found that structure protein boundary film on rubbing surface a key essence wear reduction hydrogel. The aim this study to understand mechanisms through in situ observation forming surface. Reciprocating apparatus was constructed stage inverted fluorescent microscope. A sliding pair spherical reciprocating upper specimen and flat stationary lower cover glass tested....