Presence Of Ions Research Articles

The effect of aluminum ions and sorbitol on collagen and skin: A thermally stimulated current spectroscopy study

The influence of aluminum ions introduced either directly or with sorbitol, in collagen and skin, has been investigated by Thermally Stimulated Current/TSC spectroscopy. The intramolecular mobility of collagen has been found to be significantly reduced by aluminum ions. The substitution of water molecules by aluminum ions on intramolecular hydrophilic sites is suggested to be responsible for this evolution. The presence of sorbitol minimizes this effect. The intermolecular mobility of collagen is decreased upon introduction of aluminum ions in presence of sorbitol. This result can be explained by the interaction of sorbitol-aluminum entities with the telopeptidic regions of collagen molecules. In skin samples, the intra- and intermolecular mobilities are restored due to the combined actions of sorbitol and noncollagenous proteins and other macromolecules.

Etude par spectrometrie Mössbauer des etapes initiales du processus d'enrobage des particules aciculaires de Fe 2O 3 γ par coprecipitation des ions Co 2+ et Fe 2+

Both Mössbauer absorption and emission spectra have been investigated in order to characterize the first stages of cobalt-doping process involving the coprecipitation of cobaltous and ferrous ions in presence of acicular γ Fe 2O 3 particles in inert atmosphere. The absorption spectra reveal a rapid oxidation of Fe 2+ to Fe 3+ ions mainly involved in magnetic interactions with neighbouring cations. Such a behaviour being not observed for decayed 57Co ions which essentially remain not magnetically ordered, the results obtained suggest, in the first steps, a preferential incorporation of Fe 3+ ions in surface layer of γ Fe 2O 3 particules rather than an epitaxial formation of cobalt-ferrite layer.

Manganese-containing catalase from Thermus thermophilus peroxide-induced redox transformation of manganese ions in presence of specific inhibitors of catalase activity

The mechanism of peroxide decomposition involves: interconvertion of two equally active redox states: (Mn 2+, Mn 2+) and (Mn 3+, Mn 3+) states. Various inorganic anions such as Cl − or HPO − 4 inhibit catalase activity by binding to the (Mn 2+, Mn 2+). This inhibition can also be observed following reduction of the (Mn 3+, Mn 3+) states to (Mn 2+, Mn 2+) by peroxide. The (Mn 3+, Mn 4+) state, which can be formed by periodate oxidation, does not interact with these anions and is inactive in peroxide decomposition. The (Mn 2+, Mn 3+) state, which forms in a minority of centers by auto-oxidation, also appears not to participate in a major way in peroxide decomposition.

Possible involvement of Ca++ ions, protein kinase C and Na+-H+ antiporter in insulin-induced endogenous dopamine release from tuberoinfundibular neurons

Insulin (63 μM) stimulated endogenous dopamine (DA) release from tuberoinfundibular neurons. This effect was independent on the presence of extracellular glucose and did not involve the outward transport of DA, mediated by its membrane carrier. By contrast this effect was completely prevented by the removal of extracellular Ca++ ions in presence of the Ca++- chelator ethyleneglycol-2- (2-aminoethyl)-tetracetic acid (EGTA). Furthermore 1-(5-isoquinolinyl-sulfonyl)-2-methyl-piperazine (H7), a compound which behaves as a putative inhibitor of protein kinase C (PK-C) (10μM), completely counteracted the stimulation of endogenous DA release induced by insulin. Amiloride (300 μM) and its 5-amino nitrogen atom-substituted derivative, 5-(N-methyl-N-(guanidinocarbonylmethyl) amiloride (MGCMA) (10 μM), a highly selective inhibitor of the Na+-H+ membrane antiporter, were both able to prevent the stimulatory action exerted by insulin on endogenous DA release. Collectively, these results suggest that the transductional events by which insulin stimulated endogenous DA release from TIDA neurons may involve the activation of PK-C, the enhancement of Ca++ influx and the stimulation of the Na+-H+ exchange system.

Kinetics of Reaction of n-Pentyl Bromide with Sulphite Ion in Presence of Surfactants

Kinetics of Reaction of n-Pentyl Bromide with Sulphite Ion in Presence of Surfactants

Polarographic Behaviour of some Metal Ions in Presence of Pyruvate

Polarographic Behaviour of some Metal Ions in Presence of Pyruvate

Kinetics of Reaction of n-Pentyl Bromide with Sulphite Ion in Presence of Surfactants

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Solvent Effect on the Kinetics of Reaction between Methyl Orange and Peroxydisulphate Ion in Presence of Bromide Ion - Separation into Transition State and Reactant Components

Solvent Effect on the Kinetics of Reaction between Methyl Orange and Peroxydisulphate Ion in Presence of Bromide Ion - Separation into Transition State and Reactant Components

Polarographic Behaviour of some Metal Ions in Presence of Pyruvate

Polarographic Behaviour of some Metal Ions in Presence of Pyruvate

Stochastic wave‐kinetic theory of radiative transfer in the presence of ionization

The stochastic wave‐kinetic theory at the level of the first‐order smoothing approximation is used to construct a radiative transfer equation for a simple model of a weakly inhomogeneous, weakly non‐stationary, and locally isotropic cold turbulent plasma. All the coefficients in the resulting equation are expressed systematically in terms of the electrodynamic and statistical properties of the medium without the usual recourse to phenomenological arguments.

Tracer-diffusion of cobalt ions in sodium and potassium nitrates in agar gel

Tracer-diffusion of Co2+ ions is studied in agar gel in the presence of sodium and potassium nitrates at 25°C. The diffusion coefficient values at various electrolyte concentrations are compared with the corresponding theoretical values computed on the basis of Onsager's theory. The deviations from the theory are attributed to the various co-occurring effects in the diffusion medium. The activation energy for the process of diffusion of Co2+ ions in presence of above electrolytes is also reported.

Tracer diffusion of cobalt ions in some alkali metal chlorides

The concentration dependence of experimental diffusion coefficients of cobalt ions in presence of some alkali metal chlorides is examined in the light of the Onsager theory. The diffusion coefficients are measured in 1% agar gel using the zone-diffusion technique. The positive and negative deviations observed at higher and lower concentrations, respectively, are explained in terms of relative contributions of various types of effects occurring in the diffusion medium.

Interactions between alkyl xanthates and cationic micelles

Interactions between methyl, ethyl, n-buthyl, n-amyl, and n-hexyl xanthates with monomers and micelles of cetyltrimethylammonium bromide CTAB were studied. Xanthates have a pronounced absorbance peak at 301 nm which is shifted to 306 nm when in presence of CTAB micelles. A maximum difference in absortivities between the micellar bound and free xanthates was found at 313 nm. This wavelength was used to measure the amount of xanthate associated to micelles. An insoluble ion pair formed between xanthates and CTA monomers which is gradually redissolved by increasing amounts of CTAB was detected. Association constants of xanthates to CTAB micelles as well as ionic exchange constants between xanthates and added Br − ions in presence of CTAB micelles were calculated and from their values the transfer free energies Δ μ x 0 of the methyl and methylene groups of the alkyl chain of xanthates were calculated from both the association and ionic exchange constants.

Transport of ions in presence of induced electric field and electrostatic turbulence: Source of ions injected into ring current

The transport of ions from the polar ionosphere to the inner magnetosphere during stormtime conditions has been computed using a Monte Carlo diffusion code. The effect of the electrostatic turbulence assumed to be present during the substorm expansion phase was simulated by a process that accelerated the ions stochastically perpendicular to the magnetic field with a diffusion coefficient proportional to the energization rate of the ions by the induced electric field. This diffusion process was continued as the ions were convected from the plasma sheet boundary layer to the double-spiral injection boundary. Inward of the injection boundary, the ions were convected adiabatically. By using as input an O + flux of 2.8 × 10 8 cm −2 s −1 (w > 10 eV) and an H + flux of 5.5 × 10 8 cm −2 s −1 (w > .63 eV), the computed distribution functions of the ions in the ring current were found to be in good agreement, over a wide range in L (4 to 8), with measurements made with the ISEE-1 satellite during a storm. This O + flux and a large part of the H + flux are consistent with the DE satellite measurements of the polar ionospheric outflow during disturbed times.

Investigation of the coppermagnesiumalkaline phosphatase system

The effect of Mg 2+ ions on Cu 2–alkaline phosphatase has been investigated with respect to the coordination geometry of the copper ion in presence and in absence of inorganic phosphate at pH 6.0. It is somewhat puzzling that Cu 2AP binds only one phosphate ion giving rise to only one kind of ESR spectra consistent with a tetragonal structure. Cu 2Mg 4AP binds two phosphate ions, the resulting geometry being probably pseudotetrahedral. Water 1H T −1 1 measurements between 4 and 60 MHz have shown that water is present in the coordination sphere of the former derivative but not in the latter.

Decomposition of Hydrogen Peroxide catalysed by Copper Ions in Presence of Amphoteric Oxides

Decomposition of Hydrogen Peroxide catalysed by Copper Ions in Presence of Amphoteric Oxides

Decomposition of Hydrogen Peroxide catalysed by Copper Ions in Presence of Amphoteric Oxides

Decomposition of Hydrogen Peroxide catalysed by Copper Ions in Presence of Amphoteric Oxides

Study of the effect of amines on structure of coacervates formed by photochemical effect on metal ions in presence of formaldehyde

If an aqueous mixture of ammonium molybdate, diammonium hydrogen phosphate, biological minerals, and formaldehyde is exposed to sunlight, typical "Jeewanu", mixtures are observed. However, if a little solution of p-phenylene diamine, p-nitroaniline, alpha-naphthylamine or beta-naphthyl amine is added to it, a dense white precipitate is obtained. This precipitate, under a microscope at X1200 magnification, appears as large clusters of very tiny cream-coloured spherules. But if the mixture is first exposed to sunlight for four hours, when the formation of typical microstructures appears, and then the amine solution is added, the formation of the precipitate is retarded as the exposure time of amine-free mixture is enhanced, till finally the formation of spherules as precipitate is stopped. Microscopic study in twenty days of exposure of the amine-containing mixture tube shows that the number of typical microstructures decreases; they get larger in size and gradually disintegrate, while the formation of tiny sdpherules is accelerated.

Validity of a Boltzmann equation method for predicting the effect of ionization and attachment

A Boltzmann equation method has been used to predict the effect of ionization upon the electron swarm parameters in argon (Tagashira et al., 1977). As a further test of the validity of the method, it is applied to a model gas of Lucas and Saelee (1975) into which either ionization or electron attachment is incorporated. A comparison between the swarm parameters calculated by the Boltzmann equation method and by a Monte Carlo simulation of the latter authors for various values of the ionization or attachment cross-section suggests that this method deduces correctly the ionization and the attachment frequencies, and the centre-of-mass electron drift velocity, not only in the presence of ionization but also in the presence of attachment. The electron diffusion coefficients and the electron mean energy are deduced also with good accuracies.

ChemInform Abstract: POLAROGRAPHY OF SOME ANIONS IN PRESENCE OF AQUEOUS ORGANIC SOLVENT MIXTURES‐ REDUCTION OF IODATE IONS IN PRESENCE OF VARIOUS BASE ELECTROLYTES

Chemischer InformationsdienstVolume 8, Issue 27 Physical Inorganic Chemistry ChemInform Abstract: POLAROGRAPHY OF SOME ANIONS IN PRESENCE OF AQUEOUS ORGANIC SOLVENT MIXTURES- REDUCTION OF IODATE IONS IN PRESENCE OF VARIOUS BASE ELECTROLYTES B. K. GUPTA, B. K. GUPTASearch for more papers by this authorD. S. JAIN, D. S. JAINSearch for more papers by this authorJ. N. GAUR, J. N. GAURSearch for more papers by this author B. K. GUPTA, B. K. GUPTASearch for more papers by this authorD. S. JAIN, D. S. JAINSearch for more papers by this authorJ. N. GAUR, J. N. GAURSearch for more papers by this author First published: July 5, 1977 https://doi.org/10.1002/chin.197727030Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume8, Issue27July 5, 1977 RelatedInformation