Published by Elsevier B V”
“Dynamic stabilization systems are emerging as an alternative to fusion instrumentation. However, cyclic loading and micro-motion at various interfaces may produce wear debris leading to adverse tissue reactions such as osteolysis. Ten million cycles of wear test was performed for PercuDyn(TM) in axial rotation and the wear profile and the wear rate was mapped. A validation study was undertaken to assess the efficiency of wear debris collection which accounted for experimental
errors. The mean wear debris measured at the end of 10 million cycles was 4.01 mg, based on the worst-case recovery Androgen Receptor inhibitor rate of 68.2%. Approximately 40% of the particulates were less than 5 mu m; 92% less than 10 mu
m. About 43% of particulates were spherical in shape, 27% particulates were ellipsoidal and the remaining particles were of irregular shapes. The PercuDyn(TM) exhibited an average polymeric wear rate of ICG-001 0.4 mg/million cycles; substantially less than the literature derived studies for other motion preservation devices like the Bryan disc and Charite disc. Wear debris size and shape were also similar to these devices.”
“The effect of pectin charge density on the formation of multilayer films with chitosan (PEC/CHI) is studied by means of electro-optics. Pectins of low (21%) and high (71%) degrees of esterification, which are inversely proportional to the pectin charge density, are used to form films on colloidal beta-FeOOH particles at pH 4.0 when the CHI is fully
ionized. We find that, after deposition of the first 3-4 layers, the film thickness increases linearly with the number of adsorbed layers. However, the increase in the film thickness is larger when the film is terminated with CHI. Irregular increase of the film thickness is more marked for the PEC with higher density of this website charge. Oscillation in the electrical polarizability of the film-coated particles with the number of deposited layers is also registered in the PEC/CHI films. The charge balance of the multilayers, calculated from electrical polarizability of the film-coated particles, is positive, with larger excess of positive charge within the film constructed from CHI and less charged PEC. This is attributed to the ability of CHI to diffuse into the film at each deposition step.