Significant cleavage by hammerhead ribozymes requires activation by divalent metal ions. Several models have been proposed to account for the influence of metal ions on hammerhead activity. A number of recent papers have presented data that have been interpreted as supporting a one-metal-hydroxide-ion mechanism. In addition, a solvent deuterium isotope effect has been taken as evidence against ...

We studied the electric properties of phosphatidylcholine bilayers modified with crown ether (dibenzo[18] crown-6). The studies were carried out for various crown ether concentrations in forming solutions and various potassium ion concentrations in electrolyte solutions. The presence of crown ether in the membrane influences the membrane's impedance; there is a reduction in its resistivity, a d...

Ion concentration polarization (CP, current-induced gradient adjacent to a charge-selective interface) has been well studied for single-phase mixed conductors (e.g., liquid electrolyte), but multiphase CP rarely addressed in literature. In our recent publication, we proposed that above certain threshold currents can flip the phase distribution ion-intercalation nanofilms sandwiched by ion-block...

We report experimental and theoretical studies on ring cleavage enhancement in collisions of potassium atoms with uracil/thymine to further increase the understanding of the complex mechanisms yielding such fragmentation pathways. In these electron transfer processes time-of-flight (TOF) negative ion mass spectra were obtained in the collision energy range 13.5-23.0 eV. We note that CNO(-) is t...

Z. Naturforsch. 55 b, 1121-1123 (2000); received September 18, 2000 Charge Transfer, Peroxoborate, Chemiluminescence Peroxoborate and the oxidizing cations [Co(NH3)6]3+, [Ru(NH3)6]3+ and N,N'-dimethyl-4,4'bipyridinium2+ (paraquat2+) form ion pairs in aqueous solutions which display outer-sphere charge transfer (OSCT) bands in their absorption spectra. This CT involves an electronic transition f...

Ion channels present a group of targets for major clinical indications, which have been difficult to address due to the lack of suitable rapid but biologically significant methodologies. To address the need for increased throughput in primary screening, the authors have set up a Beckman/Sagian core system to fully automate functional fluorescence-based assays that measure ion channel function. ...

In this article we investigate the effect of monovalent cations (Li(+), Na(+), K(+), Cs(+)) on self-assembly of thiol-modified double-stranded DNA (ds-DNA) and single-stranded DNA (ss-DNA) on gold electrodes. Electrochemical characteristics (surface coverage, ion penetration and charge transfer) of ds-DNA and ss-DNA self-assembled monolayers (SAMs) formed with different monovalent cations are i...