Plasma processes analog

The steady-state balance of the Ca pump and plasma membrane leaks of Ca determines the resting intracellular free Ca concentration. Kinetically, all the other membrane bound compartments and their transport processes are analogous to buffer systems with various rates of binding and release. The essential point is that all the other pools must come to steady-state with the intracellular free concentration. Thus, the plasma membrane Ca -pump for the Ca economy of the cell has primacy. 

A plot of rate of transport against solute concentration in the tubule (Figure 8.3) shows fm, the tubular transport maximum to be analogous with Vmax for an enzyme, which is a maximum rate of solute transport across tubular cells. Assuming a fixed GFR, the point at which the plotted line begins to deviate from linearity, indicates that the substance exceeds a critical threshold concentration and begins to be excreted in the urine. When the plotted line reaches a plateau indicating that saturation point, that is tm has been reached, the rate of excretion is linear with increase in plasma concentration. The concept of fm as described here for tubular reabsorption applies equally well to carrier-mediated secretory processes. If the fm value for a particular is exceeded for any reason, there will be excretion of that solute in the urine. 

Other CVD Processes. CVD also finds extensive use in the production of protective coatings (44,45) and in the manufacture of optical fibers (46-48). Whereas the important question in the deposition of protective coatings is analogous to that in microelectronics (i.e., the deposition of a coherent, uniform film), the fabrication of optical fibers by CVD is fundamentally different. This process involves gas-phase nucleation and transport of the aerosol particles to the fiber surface by thermophoresis (49, 50). Heating the deposited particle layer consolidates it into the fiber structure. Often, a thermal plasma is used to enhance the thermophoretic transport of the particles to the fiber walls (48, 51). The gas-phase nucleation is detrimental to other CVD processes in which thin, uniform solid films are desired. 

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