AB STRACT The effects of external Zn+2 and other divalent cations on K channels in squid giant axons were studied. At low concentration (2 mM) Zn+2 slows opening kinetics without affecting closing kinetics . Higher concentrations (5-40 mM) progressively slow opening and speed channel closing to a lesser degree. In terms of "shifts," opening kinetics are strongly shifted to the right on the volt...

Ionizations of 2-substituted l,l-dimethyl-3,4-methano-1,2,3,4-tetrahydronaphthalen-2-ols (8) (3,3-dimethylbenzobicyclo[4.1 .O]heptan-2-ols) in FS03H/S02CIF at -1 30 O C do not yield the corresponding 2-cations but benzylic (4-) cations 10 as a result of cyclopropylcarbinyl~yclopropylcarbinyl rearrangements. At higher temperatures, 10a and 10b undergo a further series of rearrangements to yield ...

background: there are great resources of natural zeolite in iran. zeolite, an inorganic ion-exchanger, may be used as a suitable technical-economical solution for water treatment in many regions of iran. in this study, the characterization of natural zeolite natrolite and the feasibility of removing hardness, cations, and anions were investigated. methods: first, zeolite composition and type we...

the complexive abilities of 5,11,17-tddert-butyl-23 amino-25.26,27,28-tet3propoxy-calix[4]arere and5,1127-tri-amino-23 acelyktert-butylamide-25,26,27,28-tetrabutoxy-calixplarene towards alkali metalions lit nat, kt ric and cs+ in methanol-chloroform mixture have been evaluated at 25 °c, using uvvis spectrophotometric techniques. the results showed that the hgands are capable to complex with all...

Manifestations of excitation-contraction (EC) coupling of skeletal muscle were studied in the presence of metal ions of the alkaline and alkaline-earth groups in the extracellular medium. Single cut fibers of frog skeletal muscle were voltage clamped in a double Vaseline gap apparatus, and intramembrane charge movement and myoplasmic Ca2+ transients were simultaneously measured. In metal-free e...