Oxygen-mediated diffusion

Further evidence for the OHb pairs is given in an STM movie recorded at approximately 187 K. The movie shows the OHb pairs separating across the Ob rows via proton exchange with water molecules [19]. Key frames from the movie are shown in Figure 8.5. This water-assisted OHb diffusion mechanism is supported by calculations, which show that the barrier to diffusion is lowered by the exchange with water. The same diffusion mechanism is also observed for isolated OHb and because of the misassignment of OHb and Ob-vacs by Schaub et al. [15], this water-mediated diffusion of OHb was incorrectly reported as oxygen-mediated diffusion of Ob-vacs [32, 33] via a mechanism inconsistent with subsequent isotope studies [34],... 

Analogons to column (F), colunm (I) this time contains the calcnlated nitrate concentrations which again are coimected with loops to the columns (G) and (H). However, in the case of nitrate, there is also some release into the pore water fraction due to the oxygen mediated decomposition of organic substances. Thus, each cell belonging to column (I) is calculated from its previous value, from the diffusive import from above, from the diffusive export downwards, from the import from the oxidation of organic material mediated by oxygen (here, selective C N ratio), as well as from the decomposition mediated by nitrate. For cell 112, this reads in Excel notation as follows ... 

It is important to note that the SO + O chemiluminescence reaction can be surface mediated in addition to occurring in the gas phase. Here, the oxygen atoms are weakly bound to the surface and react with SO diffusing to the surface ... 

Surface path at low overpotential. Qualitative and quantitative analysis of impedance data, tracer studies, as well as various studies of thin-film electrodes suggest that under low-overpotential LSM operates primarily via a surface-mediated mechanism (like Pt). This conclusion appears to be consistent with the properties of LSM, which is fully oxygen stoichiometric under ambient Pq. However, little is known about how far the active region of reduction extends beyond the solid/solid interface (via surface diffusion) or the relative importance of chemical steps (on the LSM surface) vs electrochemical kinetics at the solid/solid interface. 

Anandamide can be transported inside neural cells (neurons and glia) by a carrier-mediated facilitate diffusion mechanism (Beltramo et al., 1997) and transformed through two main pathways (1) hydrolysis to arachidonic acid and ethanolamine, and (2) oxidation to various oxygenated derivatives. 

AG is internalized inside the cells through either passive diffusion or carrier-mediated transport. Once inside the cell, 2-AG can be transformed through three main mechanisms (1) hydrolysis to arachidonic acid and glycerol (2) oxidation to a series of oxygenated derivatives and (3) anabolic metabolism (Fig. 2). 

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