1. A comparative study has been made of the diffusibility of calcium in solutions of crystalline egg albumin, serum globulin, and human blood serum. 2. In all three of these solutions, at pH 7.4, molal Ca concentrations within the membrane are greater than the calcium concentrations in the outside solutions, quite in accordance with the Donnan theory. 3. At pH 7.4, the ratio of See PDF for Stru...

Knowledge of location and magnitude of charge density, together with the pore morphology allows one to calculate the Donnan potential, characterizing ion exclusion in charged porous materials. Use of the electro-chemical potential together with Gauss’ electrostatic theorem allows the computation of the ion and voltage distribution at the microscale. On the other hand, commonly used macroscopic ...

It has been suggested that potentials measured with conventional microelectrodes in chemically or mechanically skinned muscle fibers arise from a Donnan equilibrium due to myofilament fixed charges. This hypothesis was tested in mechanically skinned frog (Rana pipiens) semitendinosus fibers by measuring the distribution potential (Ed) between fiber and bath with 3 M KCl-filled microelectrodes a...

reference electrode (3). The ionized calcium concentration of sequential retentates prepared by ultrafiltration of a human control serum increased with increasing protein concentration in a way consistent with Donnan theory (4, 5) when the analyzers’ standard reference-electrode liquid junctionswere used; however, the ionized calcium in the same retentates declined slightly with increasing prot...

The streaming potentials of two different nanofiltration membranes were studied with several electrolyte solutions to investigate the influence of salt type and concentration on the zeta potential and kinetic surface charge density of the membranes. The zeta potentials decreased with increasing salt concentration, whereas the kinetic surface charge densities increased. The kinetic surface charg...

The classical Gibbs-Donnan equilibrium describes excess osmotic pressure associated with confined colloidal charges embedded in an electrolyte solution. In this work, we extend this approach to describe the influence of multivalent ion binding on the equilibrium force acting on a charged rod translocating between two compartments, thereby mimicking ionic effects on force balance during in vitro...

Although Frederick George Donnan (Fig. 1) grew up in Northern Ireland, actually he was born in Columbo, Ceylon (now Sri Lanka), on September 5, 1870 (1). He lost the sight of his left eye at the age of nine but did not allow this accident to handicap him. As a schoolboy, his main interest was in mathematics and physical science. He attended the Belfast Royal Academy from 1880 to 1889; and altho...