Trivalent Ions (trivalent + ion)

Distribution by Scientific Domains

Selected Abstracts

Growth of trivalent ions doped PbWO4 crystals and their scintillation properties

C. H. Yang
Abstract Undoped and series of trivalent ions(including La, Y, Gd and Tb) doped PWO crystals were grown from 5N raw materials by using Czochralski technique. Trivalent ions doping improved the transmittance, fast components of luminescence and radiation damage resistance for compensating structure defects. Corresponding, the fraction of light yield at shorter collecting time was increased. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Selective Lanthanides Sequestration Based on a Self-Assembled Organosilica

Eric Besson Dr.
Abstract In this paper, we investigate the cation-exchange properties of a self-assembled hybrid material towards trivalent ions, lanthanides (La3+, Eu3+, Gd3+, Yb3+) and Fe3+. The bis-zwitterionic lamellar material was prepared by sol,gel process from only 3-aminopropyltriethoxysilane (APTES), succinic anhydride, and ethylenediamine. In ethanol heated under reflux, the exchange ethylenediammonium versus Ln3+ proved to be complete by complexometry measurements and elemental analyses, one Cl, ion per one LnIII remaining as expected for charge balance. In aqueous solution at 20,°C, the material was found to be selective towards lanthanide in spite of the similarity of their ionic radii. The cation uptake depends on the nature of the salt, the difference between two lanthanides reaching up to 20,% in some cases. Finally, ion-exchange reaction with FeCl3 was chosen as a probe to get more information on the material after incorporation of trivalent ions. Based on Mössbauer spectroscopic investigations on the resulting material in conjunction with the XRD analysis of materials containing trivalent ions, a structural model was proposed to describe the incorporation of trivalent ions by exchange reaction within the original zwitterionic material. [source]

Dynamics of Full Fusion During Vesicular Exocytotic Events: Release of Adrenaline by Chromaffin Cells

CHEMPHYSCHEM, Issue 2 2003
Christian Amatore Prof.
Abstract Vesicular exocytosis is important in the communication between cells in complex organisms. It controls the release of specific chemical or biochemical messengers stored in the emitting cell, which elicit a response upon detection by the target cells. Secretion of a messenger molecule (a neurotransmitter) was measured electrochemically, which allowed the quantification of cellular events and the validation of current physicochemical models. This model led us to formulate predictions about the occurrence and kinetics of vesicular exocytotic events based on the physicochemical meaning of its key parameters. These predictions were tested successfully through a series of experiments on chromaffin cells, involving changes of osmotic conditions, presence of trivalent ions and cholesterol-induced structuring of the cell plasmic membrane. [source]