Search results for "Barium compounds"
showing 8 items of 8 documents
Antispasmodic effect of 4'-methylepigallocatechin on guinea pig ileum.
2012
AbstractThe antispasmodic effect of 4′-methylepigallocatechin (MEC), which was isolated from Maytenus rigida Mart (Celestraceae), was investigated in vitro in guinea pig intestinal segments. In the isolated ileum, MEC (1 nM–100μM) did not modify the ileal spontaneous tonus or the electrically elicited contractions. MEC (8μM) significantly (p<0.01) reduced the submaximal contractions induced by histamine (2μM), carbachol (100μM) and BaCl2 (0.03M). An additive relaxing action (p<0.001) was observed by co-incubation of verapamil (10 nM) and MEC (8μM). Although MEC (1nM–100μM) did not modify the contractions elicited by 60mM KCl, it significantly reduced the CaCl2 contractile response without c…
High-pressure study of the behavior of mineral barite by x-ray diffraction
2011
In this paper, we report the angle-dispersive x-ray diffraction data of barite, BaSO 4, measured in a diamond-anvil cell up to a pressure of 48 GPa, using three different fluid pressure-transmitting media (methanol-ethanol mixture, silicone oil, and He). Our results show that BaSO 4 exhibits a phase transition at pressures that range from 15 to 27 GPa, depending on the pressure media used. This indicates that nonhydrostatic stresses have a crucial role in the high-pressure behavior of this compound. The new high-pressure (HP) phase has been solved and refined from powder data, having an orthorhombic P2 12 12 1 structure. The pressure dependence of the structural parameters of both room- and…
Desulfurization: Critical step towards enhanced selenium removal from industrial effluents
2017
Abstract Selenium (Se) removal from synthetic solutions and from real Flue Gas Desulfurization (FGD) wastewater generated by a coal-fired power plant was studied for the first time using a commercial iron oxide impregnated strong base anion exchange resin, Purolite ® FerrIX A33E. In synthetic solutions, the resin showed high affinity for selenate and selenite, while sulfate exhibited a strong competition for both oxyanions. The FGD wastewater investigated is a complex system that contains Se (∼1200 μg L −1 ), SO 4 2− (∼1.1 g L −1 ), Cl − (∼9.5 g L −1 ), and Ca 2+ (∼5 g L −1 ), alongside a broad spectrum of toxic trace metals including Cd, Cr, Hg, Ni, and Zn. The resin performed poorly again…
Possible Ca 2+ -dependent mechanism of apical outer hair cell modulation within the cochlea of the guinea pig
1998
Calcium ions were precipitated with potassium antimonate after injection of the inorganic calcium channel blocker MnCl2 or the inorganic potassium channel blockers BaCl2 or CsCl into the perilymph of the scala vestibuli of the guinea pig. The spatial distribution of the formed histochemical reaction products within the organ of Corti was studied by energy-filtering transmission-electron microscopy. Compared with untreated control ears, the number of the formed precipitates drastically increased at the extracellular side of the lamina reticularis after application of the various inorganic channel blockers. The apical side of the outer hair cells and the intervening Deiter cells were covered …
4-Aminopyridine and barium chloride attenuate the anti-epileptic effect of carbamazepine in hippocampal slices
1991
The exact mode of action of the anti-epileptic agent carbamazepine is unknown. In hippocampal slices in which epileptiform discharges were induced by addition of penicillin to the perfusion medium, the depressant effect of carbamazepine was attenuated by the potassium-channel blockers barium chloride (0.1 mM) and 4-aminopyridine (200 microM), which suggested that potassium fluxes might be involved in the mechanism of action of carbamazepine.
Xenotransplantation of parathyroids in rats using barium-alginate and polyacrylic acid multilayer microcapsules
2001
The integrity and function of encapsulated parathyroid tissue following xenotransplantation is limited by oxygen and nutrition supply and capsule fibrosis. Since some of these factors depend on stability and biocompatibility of the coating material, multilayer microcapsules have been developed. Parathyroid tissue pieces and digested single cells from pigs were encapsulated in barium-alginate and in polyacrylic acid (PAA) multilayer capsules. After 7 days of culture the function of the encapsulated cells were assessed. Subsequently, in a part of the cultured microcapsules the viability was directly assessed whereas the other part was transplanted in dark animal [DA] rats for 30 days. After e…
Trap Spectroscopy by the Glow Rate Technique using Bleaching of Colour Centres
2002
An application of the glow rate technique (GRT) for analysis of the parameters of thermostimulated decay of colour centres is presented using the data on the decay of radiation defects in LiBaF 3 :Fe crystals created by X rays at 300 K. The GRT offers a procedure for evaluation of the mean activation energy as a function of temperature in the case of arbitrary thermostimulated relaxation kinetics represented by the trap distribution function. The experimental procedure involves at least two subsequent measurements of thermostimulated decay kinetics at different heating rates. It is shown that the decay of the F type centres is governed by interaction of mobile anion vacancies with F A and F…
Analysis of the hyperpolarizing effects of forskolin in guinea-pig atrial heart muscle.
1988
The effects of forskolin on action potential configuration and on both uptake and efflux of 86Rb+ were studied in guinea-pig left atria. The action potential was prolonged by forskolin in the plateau range but shortened at the end of repolarization; maximal upstroke velocity and amplitude of slow response potentials were enhanced. In partially depolarized preparations, the resting potential was increased by forskolin; this effect was not prevented by atropine 1 μmol/1. Forskolin augmented the rate constant of 86Rb+ efflux in beating and in resting preparations. The uptake of 86Rbs+ was enhanced by forskolin in resting preparations. It is concluded that forskolin stimulates the Na+, K+ -pump…