Macromolecules Across Membranes

There are various models that describe the passage of molecules across membranes. In order to rule out the effect of the size of the passage, it is assumed that the solutes will be uncharged and spherical. There are size-selective models that are used to analyze experimental data. These models are the one- or two- pore analysis and the normal or lognormal pore distribution modes. Previous analysis has shown that the heteroporous equations had similar results and the homoporous equations were unable to simulated biological data.
From there, a set of physiological equations is used to compare the experimental sieving data for the Ficoll molecules that can consist of different radii. In that aspect the Iterative calculations contain four unknown parameters r_s,r_L,f_L,and A_0/∆X. Reasonable initial values are needed for the parameters to achieve the best fit between the modeled data and the experimental data. This is then used to compute the residual square sum. It is also important to know the fluxes of fluid and solutes that pass by each pore pathway are through a heteroporous membrane. The value needed is the total hydraulic conductance, L_p S, equals that for the small (s) and large (L) pores, and f_L is the fraction of LpS accounted for by the large-pore pathway. The equation is as follows: …show more content…
When the reflection coefficient approaches zero then that means are very large pores and when its approaching unity then the membrane is semipermeable. The following equation is for a heteroporous membrane σ ̅=f_s σ_s+f_L σ_L (8)
An example is used to calculate the solute (CI) passing through each pore pathway. A nonlinear flux equation where the fluid flux, J_V,is used to do