1. When a solution of a salt of gelatin or crystalline egg albumin is separated by a collodion membrane from a watery solution (free from protein) a potential difference is set up across the membrane in which the protein is positively charged in the case of protein-acid salts and in which the protein is negatively charged in the case of metal proteinates. The turning point is the isoelectric po...

Proper evaluation of the intrinsic stability metal complexes with humic nanoparticles calls for a robust representation particulate electrostatic features. Addressing here case trivalent association humics which significant contribution is expected, we report interpretative approach as an alternative to conventional but approximative Donnan model applied in popular speciation codes. The chemica...

In a paper on the factors controlling the electrolyte and water distribution in the blood Van Slyke, Wu, and McLean (1) based their mathematical deduction on three fundamental postulates: (1) Approximate neutrality of the blood reaction; sum of base cations equals sum of anions. (2) Validity of Donnan’s law of membrane equilibrium. (3) Equality of the osmotic pressure of the fluid within the ce...

Sedimentation equilibrium was achieved with turnip yellow mosaic virus at low speeds (600 rpm) in a magnetic ultracentrifuge. The experiments were carried out in the newly installed constant-speed rotor, equipped with automatic control and an electromagnetic drive. A particle mass of 5.55 x 10(6) daltons was calculated for the virus at vanishing concentrations, in essential agreement with the e...

The determination of free Zn(2+) ion concentration is a key in the study of environmental systems like river water and soils, due to its impact on bioavailability and toxicity. AGNES (Absence of Gradients and Nernstian Equilibrium Stripping) and DMT (Donnan Membrane Technique) are emerging techniques suited for the determination of free heavy metal concentrations, especially in the case of Zn(2...

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 properties of biofilm EPS are determined by the multiple interactions between its constituents and surrounding environment. Because high complexity EPS, constituents' characterisation is still far from thorough, identification these cannot be done yet. Therefore, we use gels bacterial alginate-like exopolysaccharides (ALEs) as a model component for in this work. These have been examined the...

Colloid osmotic pressures of the body fluids of twenty invertebrate species were measured directly. The results, which are generally lower than predicted values for the same species, pertain to several physiological questions: (1) they do not quantitatively explain the frequently observed hyperosmoticity of body fluids in species believed to be osmoconformers, indicating that the condition cann...

Perineuronal nets (PNs) are a specialized form of brain extracellular matrix, consisting of negatively charged glycosaminoglycans, glycoproteins and proteoglycans in the direct microenvironment of neurons. Still, locally immobilized charges in the tissue have not been accessible so far to direct observations and quantifications. Here, we present a new approach to visualize and quantify fixed ch...