Visible mechanism profile

Scheme 13.1 Mechanism profile of visible-light-induced photocatalysis.

The depth profiling technique used on samples with a barrier film before and after the addition of chloride to the buffering borate electrolyte showed no indication of either chloride penetration or significant reduction of the average oxide layer thickness.123 This, of course, does not rule out the possibility of the formation, by any of the mechanisms suggested above, of pinholes with radii much smaller than that of the ion-gun beam, through which the entire active dissolution could take place, or the possibility that the beam missed pits formed sporadically across the surface. If pinholes which are not visible were formed, the dissolution should proceed in them with extremely high true current densities. 

In the presence of the cosubstrate ATP at a physiological concentration of 2 mM, a certain fraction of unfolding traces shows an additional energy barrier that is not visible without ATP (see Fig. 15.3). Since TK does not bind ATP in its autoinhibited conformation, this is already a first hint that the binding pocket is mechanically opened and that binding of ATP causes a force peak in the unfolding profile due to its interactions. 

In addition, oxidative degradation related to poor consolidation has been found in both in vivo and shelf-aged prostheses that were either gamma sterilized or ethylene oxide gas (EtO) sterilized (Costa et al. 2002). When oxidation related to consolidation occurs, the oxidation profile through the cups section is inhomogeneous and the maximum oxidation is observed near the center of the prosthesis. It is worth mentioning that this consolidation-related oxidation mechanism is often accompanied by whitening of the material, visible to the naked eye. 

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