Second electron affinities of AuN and AgN clusters and the dissociation energies for fission of the AuN 22 and AgN 22 dianions are calculated using the finite-temperature shell-correction method and allowing for triaxial deformations. Dianionic clusters with N.2 are found to be energetically stable against fission, leaving electron autodetachment as the dominant decay process. The second electr...

The radioactive isotope 22 Na is one of the primary tracer isotopes that may potentially be detectable by gamma-ray spectroscopy. This isotope is predicted to be produced in ONe nova explosions, yet no detection of its 1.275 MeV gamma-ray signature has been reported so far. In particular, 6 years of COMPTEL observations of the galactic bulge, a region that should be particularly rich in nova ex...

Thellungiella halophila is a useful model species for research into plant salt tolerance. It is closely related to Arabidopsis thaliana, but shows considerably higher salt tolerance. Comparative analysis of ion homeostasis in the two species allows the identification of ion transport pathways that are critical for salt tolerance and provides the basis for future studies into their molecular fea...

Individuals genetically susceptible to hypertension may have preexisting membrane defects influencing cell sodium permeability. Fourteen Minnesotan families of Northern European descent were selected as having one or both progenitors with either high (HP) or low (LP) erythrocyte sodium permeability. We earlier found that over one-half of the (22)Na(+) influx into HP erythrocytes can be inhibite...

The effects of receptor activation were studied on the interaction of perhydrohistrionicotoxin (H(12)-HTX) with the ionic channel of the nicotinic acetylcholine (AcCho) receptor in membranes from the electric organ of Torpedo ocellata and with the endplate region of the soleus muscle of the rat. In Torpedo membranes, the initial rate (i.e., within 30 sec) of [(3)H]H(12)-HTX bindings to the ioni...

Cyclic AMP is a ubiquitous second messenger produced in cells in response to extracellular stimulants. The aim of this study was to examine its role in the regulation of amiloride-sensitive electrogenic Na(+) absorption in the rat distal colon by measuring the short-circuit current (I(sc)) and (22)Na(+) fluxes in a chamber-mounted mucosal sheet. Forskolin stimulated the amiloride-inhibitable I(...

Bartter syndrome (BS) is a heterogeneous renal tubular disorder affecting Na-K-Cl reabsorption in the thick ascending limb of Henle's loop. BS type I patients typically present with profound hypokalemia and metabolic alkalosis. The main goal of the present study was to elucidate the functional implications of six homozygous mutations (G193R, A267S, G319R, A508T, del526N, and Y998X) in the bumet...

Insulin was reported to decrease Na(+)/H(+) exchange activity in murine vascular smooth muscle (VSM) tissue. In most other cells, insulin increases activity. We tested the effects of insulin on Na(+)/H(+) exchange activity in primary cultured canine VSM cells. Intracellular pH (pH(i)) was measured with 2',7'-bis(2-carboxyethyl)-5-carboxyfluorescein fluorescence and Na(+) uptake by isotopic meth...