The effects of extracellular rubidium chloride (1, 2, 4, and 8 HIM) on simultaneously recorded transmembrane action potentials and contractions of human papillary muscle in potassium-free solutions were investigated. In KCl-free solution, reduction in the duration of the action potential at the 25% and 50% levels of repolarization was associated with an increase in the force of contraction. Exp...

1. The midgut contains a 'pool' which must mix with tracer added to the blood-side, before the transported potassium reaches a steady specific activity. The size and mixing time of the pool can be deduced from the time-course of rate of appearance of tracer on the lumen-side, the tracer influx. The theory has been extended to cover cases where the pool-size and the transport rate vary with time...

THE measurement of organ blood flow in the intact animal and man is limited primarily to methods relying either on the Fick principle or on the dye-dilution method.'-3 Measurement of coronary flow in man has been accomplished by the uptake of an inert diffusing gas, nitrous oxide, by the heart muscle.4 This method requires that a state of equilibrium between the coronary circulation and the myo...

In this work CsPbIBr2 is doped with rubidium, where up to 12% of caesium atoms are replaced those rubidium. The obtained Cs1 ? xRbxPbIBr2, x= (0, 0.02, 0.04, 0.06, 0.08, 0.10, 0.12), films were characterized by X-ray diffraction (XRD), the scanning electron microscope (SEM), photoluminescence (PL) and UV–visible spectroscopy. integration Rb+ ions into lattice leads a detectable change in optoel...

We have grown crystals of solid argon doped with rubidium atoms. The spectrum of the implanted atoms depends on the crystal-growth temperature and annealing history. We have used optical pumping to polarize the spin state of the implanted atoms and polarization spectroscopy to detect the spin state and measure the spin-relaxation time. In addition to the desired optical pumping, we also observe...

The Na/K-ATPase has been shown to bind 1 and 0.5 mol of (32)P/mol of alpha-chain in the presence [gamma-(32)P]ATP and [alpha-(32)P]ATP, respectively, accompanied by a maximum accumulation of 0.5 mol of ADP-sensitive phosphoenzyme (NaE1P) and potassium-sensitive phosphoenzyme (E2P). The former accumulation was followed by the slow constant liberation of P(i), but the latter was accompanied with ...

Valinomycin-induced uptake of rubidium by membrane vesicles prepared from Escherichia coli, Staphylococcus QUreus, and Micrococcus denifrificans is analogous in nearly all respects to the transport of sugars or amino acids, or both, by these membrane vesicles. In E. coli membrane vesicles, concentrative rubidium uptake is stimulated maximally by D-lactate and by the artificial electron donor as...

Significant correlation has been shown between the severity of coronary disease and level of coronary blood flow as measured by the rubidium coincidence technique. Contrary to the commonly expressed view, however, the rubidium coincidence method does not evaluate nutritional flow, but estimates total coronary blood flow (CBFT). An equation is derived that does evaluate nutritional flow (CBFN), ...

To study the relationship of the serum digoxin concentration to the digoxin effect on monovalent cation transport during the quinidine-digoxin interaction, we used radiolabeled rubidium to measure monovalent cation active transport in myocardial biopsy samples from dogs. In a preliminary study, we showed that quinidine did not affect rubidium uptake by myocardial samples from intact dogs. Then,...