Binary mixtures of surfactants build a binary mixed micelle in which the ratio usually differs from initial their mixture. The thermodynamic stabilization micellar pseudophase about hypothetical ideal state (intermolecular interactions between different particles and conformational states are identical to those monocomponent states) is described by molar excess Gibbs free energy (gE). dependenc...

In this study, we characterize the CCN activity of the water-soluble organics in biomass burning aerosol. The aerosol after collection upon filters is dissolved in water using sonication. Hydrophobic and hydrophilic components are fractionated from a portion of the original sample using solid phase extraction, and subsequently desalted. The surface tension and CCN activity of these different sa...

The interactions between pancreatic lipase and colipase and the substrate and the effect of bile salts on these interactions have been investigated by the use of kinetic experiments and studies on the semiquantitative phase distribution of lipase and colipase activities. The results suggest that lipase binds to hydrophobic interfaces with partial irreversible inactivation. Bile salts in the ran...

In a biological cell, proteins perform their functions in a highly complex environment comprising crowding and confinement effects as well as interactions with interfaces, cosolvents, and other biomolecules. Cosolvents can stabilize or destabilize the native folded structure of proteins in solution. Here, we present recent studies on how ionic and non-ionic cosolvents affect the interfacial aff...

Pancreatic lipase is rapidly and irreversibly inactivated at a hexadecane-water interphase. The unfolded protein is only very slowly, in the course of hours or days, released into the aqueous phase. Bile salts prevent the denaturation of the lipase. Bovine albumin also protects the enzyme. Denaturation of lipase occurs also at the interphase of the substrates, tributyrin or olive oil, and water...

The arrangement of an ionic fluorophore in the crystalline state was regulated by the presence of various counter-ions and the effect on spectroscopic and self-association properties was studied. To do so, nine salts of berberine (i.e. a fluorescent natural alkaloid) were investigated. Most of them contained organic anions and were prepared using an ion-exchange process. Berberine chloride and ...

Isothermal titration calorimetry was used to probe how salts influence the thermodynamics of binding of guests to cavitand 1. Studies involved six Hofmeister salts covering the range of salting-in to strongly salting-out. The latter were found to reduce affinity. The cause of this was competitive binding of the weakly solvated anion to the hydrophobic pocket of the host. At the other extreme of...

The three lipids in bile, cholesterol, lecithin, and bile salts (about 90 percent of the dry weight of normal gallbladder bile) are amphipathic substances having both hydrophobic and hydrophilic functional groups. Knowledge of the physicochemical factors of gallstone formation (especially cholesterol stones) has increased in the past two decades. The absolute amount of cholesterol supersaturati...

Biliary lipids (bile salts, phospholipids, cholesterol, plant sterols) were determined in 89 vertebrate species (cartilaginous and bony fish, reptiles, birds, and mammals), and individual phospholipid classes were measured in 35 species. All samples contained conjugated bile salts (C(27) bile alcohol sulfates and/or N-acyl amidates of C(27) and/or C(24) bile acids). Phospholipids were generally...

Polyethylene glycol (PEG) is widely used to sterically stabilize liposomes and improve the pharmacokinetic profile of drugs, peptides and nanoparticles. Here we report that ammonium sulfate (AS) can evoke the aggregation of PEGylated vesicles in a concentration-dependent manner. Liposomes with 5mol% PEG were colloidally stable at AS concentrations up to 0.7mM, above which they precipitated and ...