From seven different pathovars of Pseudomonas syringae representing various genetic subgroups, and one strain of Pseudomonas viridiflava the same pyoverdin siderophore (1) was isolated, probably identical with the pyoverdin whose amino acid composition (but not their sequence) had been reported before. 1 is the first pyoverdin where two of the ligands for Fe3+ are beta-hydroxy Asp units. Its re...

Ferric ion is a strength oxidant and its precipitation is an undesired phenomenon in the bioleaching process. Previous studies showed that it considerably occurs in bioleaching operations even at optimum conditions. Although there have been many reports on the Fe3+ precipitation, no study has made a mathematical modeling of the affecting parameters. The aim of the present work is the developmen...

Neutron diffraction and EXAFS experiments have been made on fluoride glasses "PbMnFeF.," and "Pb^MnFeFg" to provide informations about the magnetic short range order of pairs M-M (M = Mn"", Fe3) and the local environment of Mn and Fe3. The magnetic correlation function shows in both glasses prevailing strong antiferromagnetic first neighbour interaction at 3.6 A and two ferromagnetic interactio...

The interaction between lyophilized samples of ascorbic acid and Cu2+, Fe3+ or Mn2+ has been investigated by means of ESR spectroscopy. All of the three transition metal ions form complexes with vitamin C, but only in the case of Cu2+ and Fe3+ the interaction results in a reduction of the metal ions. Cu2+ and ascorbic acid seem to form 2 : 1 complexes with an equilibrium constant of about K = 1...

The mixed-valence tr i iron complexes [Fe3(CO)7−x(PPh3)x(μ-edt)2] (x = 0−2; edt = SCH2CH2S) and [Fe3(CO)5(κ -diphosphine)(μ-edt)2] (diphosphine = dppv, dppe, dppb, dppn) have been prepared and structurally characterized. All adopt an anti arrangement of the dithiolate bridges, and PPh3 substitution occurs at the apical positions of the outer iron atoms, while the diphosphine complexes exist onl...

available online at http://meteoritics.org 1575 © The Meteoritical Society, 2005. Printed in USA. Iron oxidation state in impact glass from the K/T boundary at Beloc, Haiti, by high-resolution XANES spectroscopy Gabriele GIULI,1* Sigrid Griet EECKHOUT,2 Eleonora PARIS,1 Christian KOEBERL,3 and Giovanni PRATESI4, 5 1Dipartimento di Scienze della Terra and INFM, Università di Camerino, Via Gentil...

Powderous crystalline materials of the composition Fe3−xMnxC have been prepared by first synthesizing Fe3C via mechanical alloying in a planetary mill followed by the addition of elemental manganese and arc-plasma melting or via the classic ceramic route in an electric furnace. The milling time for the synthesis of Fe3C was significantly reduced through adjusting the parameters of the planetary...

Mammalian ferritin from horse spleen undergoes an electrochemical or chemical reduction reaction in which each iron atom present is reduced by one electron (2300 electrons per ferritin molecule containing 2300 Fe3+ ions). Midpoint potentials of -190 mV, -310 mV, and -416 mV were determined at pH 7.0, 8.0, and 9.0. This variation of potential with pH indicates that approximately 2 H+ are transfe...

The solid-state method was used to synthesize single phase potassium-sodium niobate (KNN) co-doped with the La3+-Mn4+ and Eu3+-Fe3+ ion pairs. Structural determination of all studied solid solutions was accomplished by XRD and Rietveld refinement method. Electron paramagnetic resonance (EPR) studies were performed to determine the oxidation state of paramagnetic centers. Optical spectroscopy me...

We have investigated the magnetic structure and coupling in epitaxial [Fe3/Au(0 0 1)N/(Fe1Au1)3/Au(0 0 1)N] 2 multilayers. Our system contains alternating (Fe1Au1)3 monoatomic stacks with perpendicular magnetic anisotropy and 3 atomic layer (AL) thick Fe films (Fe3) with an in-plane easy magnetization axis, separated by an Au(0 0 1) spacer layer. Giant magnetoresistance and magnetization measur...