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 ...

Recent evidence indicates that ionic selectivity in voltage-gated Na+ channels is mediated by a small number of residues in P-region segments that link transmembrane elements S5 and S6 in each of four homologous domains denoted I, II, III, and IV. Important determinants for this function appear to be a set of conserved charged residues in the first three homologous domains, Asp(I), Glu(II), and...

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...

The transport of cations across membranes in higher plants plays an essential role in many physiological processes including mineral nutrition, cell expansion, and the transduction of environmental signals. In higher plants the coordinated expression of transport mechanisms is essential for specialized cellular processes and for adaptation to variable environmental conditions. To understand the...