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Based on certain characteristics of the acidbase quasi-equilibria and on structural properties of the synovial inhomogeneous fluid in a model articular cartilage (mAC), we try to hypothesize on its facilitated frictionlubrication mechanism. We opt for a scenario that under departure from the acid-base, pH-dependent equilibrium, directed transport of protons (H + ) is plausible, leading to a certain synergistic kinetic-thermodynamic pathway of the system as a whole. It can be viewed in such a way that protons, and virtually, other ions such as OH -; Ca 2+ , may pass through the (intra)micellar, possibly elongated spaces, playing their roles as if they were transported along temporarily formed ion (mainly, H + ) transmembrane channels. Such a hypothetical scenario would thoroughly contribute to some electrostatics-aided, interstitial (synovial) biofluid pressurization, often reported by experimentalists as the appropriate mechanism of facilitating the lubrication in a real articular cartilage (rAC) in microrheological conditions, encountered in articulating joints of mammals.

Infrared spectra, in the diffuse reflectance mode, are presented for three common softwoods (Western redcedar, southern pine, and Douglas fir) that have been subjected to a variety of artificial weathering conditions. The surface spectra of the three unweathered woods have distinctly different characteristic features, but after 2400 hours of full artificial weathering the surface features are virtually identical and correspond closely with those of the cellulosic polymer components. Weathering with light alone has a less pronounced effect on the wood surfaces, whereas weathering with water alone has virtually no effect in comparison to the result of both light and water used in conjunction. A photochemically induced reaction pathway for the weathering process, consistent with the experimental findings, is discussed.