The role of flexibility in the selectivity of calcium channels is studied using a simple model with two parameters that accounts for the selectivity of calcium (and sodium) channels in many ionic solutions of different compositions and concentrations using two parameters with unchanging values. We compare the distribution of side chains (oxygens) and cations (Na(+) and Ca(2+)) and integrated qu...

Nanopore size, shape, and surface charge all play important roles in regulating ionic transport through nanoporous membranes. The ability to control these parameters in situ provides a means to create ion transport systems tunable in real time. Here, we present a new strategy to address this challenge, utilizing three unique electrochemically switchable chemistries to manipulate the terminal fu...

an extensive study of fischer-tropsch synthesis (fts) on alumina-supported cobalt catalysts promoted with different amounts of ruthenium and rhenium is reported. up to 2 wt% of promoters, are added to the catalyst by coimpregnation. the catalysts are characterized by different methods including: bet physisorption, x-ray diffraction, hydrogen chemisorption, and temperature-programmed reduction. ...

activated charcol phase loaded with 2-propylpiperidine-1-carbodithioate (ppcd) were synthesized based on chemical binding and physical adsorption approaches. the stability of a chemically modified ppcd especially in concentrated hydrochloric acid which was then used as a recycling and pre-concentration reagent for further uses of activated charcol immobilized ppcd. the application of this activ...