The Estimation of the Diffusion Constant and Solubility of O2in Tissue Using Kinetics

✍ Scribed by HAROLD B. DOWSE; STEVEN NORTON; BRUCE D. SIDELL

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 174 KB
• Volume: 207
• Category: Article
• ISSN: 0022-5193
• DOI: 10.1006/jtbi.2000.2184

✦ Synopsis

The di!usion of a gas through a substance in which it is soluble is analogous to the passage of electric current through a circuit with both capacitance and resistance. We model steady-state di!usion employing this analogy, and extend the model to include a description of the kinetics of systems under circumstances of changing partial pressure, applying two physical constants from electrical circuitry to gas di!usion: capacitance ( ) and resistance (R). We represent the substrate of the di!usion as a capacitor being charged through a resistor after the rapid imposition of a voltage change. Using the insight derived from this model we have devised an experimental system that allows us to approximate both D, the di!usion coe$cient, and , solubility, directly from the kinetic data. We do this by recording the exponential change in P O on one side of a sheet of material both with and without the addition of a purely resistive barrier of known resistivity. The method was used to estimate D and for distilled water at a number of temperatures, olive oil, and the belly skin of Rana catesbeiana.