The kinetics of the esterification of n-butanol with acetic acid have been studied in a batch and in a tubular reactor. The best model for obtaining the esterification rate with a partially wet ion exchanger (270/o water contents) is obtained by assuming a pseudohomogeneous system, while the kinetics of dry ion exchangers is best represented by a model derived from assumptions based on a hetero...

The focus of this contribution is a comparative investigation of enantioseparations of 19 Nα-Fmoc proteinogenic amino acids on Quinine-based zwitterionic and anion-exchanger type chiral stationary phases employing hydro-organic and polar-ionic liquid and subcritical fluid chromatographic conditions. Effects of mobile phase composition (including additives, e.g., water, basis and acids) and natu...

Basolateral uptake of organic anions in renal proximal tubule cells is indirectly coupled to the Na(+) gradient through Na(+)-dicarboxylate cotransport and organic anion/dicarboxylate exchange. One member of the organic anion transporter (OAT) family, Oat1, is expressed in the proximal tubule and is an organic anion/dicarboxylate exchanger. However, a second organic anion carrier, Oat3, is also...

The Na+/H+ exchanger is a pH-regulatory protein that extrudes one H+ ion in exchange for one Na+ ion when intracellular pH declines. A number of studies have shown phorbol ester stimulation of activity in intact cells, leading to the idea that the exchanger is regulated by protein kinase C-mediated phosphorylation in vivo. cDNA encoding the protein has been cloned, and a recent model suggests a...

We have developed a novel procedure for constructing high surface area silver sinter heat exchangers. Our recipe incorporates nylon fibers having a diameter of ∼ 50 μm and thin wires of bulk silver in the heat exchanger. In order to increase the thermal conductance of liquid helium within the heat exchanger, prior to sintering, the nylon fibers are dissolved with an organic acid leaving a netwo...

Periodic mesoporous titanium phosphonate (PMTP-2) monoliths were synthesized by combining autoclaving process and evaporation-induced self-assembly strategy, which was functionalized by ClSO(3)H treatment, acting not only as an ion exchanger with large ion exchange capacity but also as a strong acid catalyst possible for some low-temperature reactions.

The plasma membranes of most if not all vertebrate cells contain a transport system that mediates the transmembrane exchange of sodium for hydrogen. The kinetic properties of this transport system include a 1:1 stoichiometry, affinity for lithium and ammonium ion in addition to sodium and hydrogen, the ability to function in multiple 1:1 exchange modes involving these four cations, sensitivity ...