. bi o - ph ] 1 5 M ay 2 00 8 Does avian magnetoreception rely on both magnetite and maghemite ?

High resolution μ-XRF topography of iron oxides inside sensory dendrites of avian magnetoreceptors

Maghemite and magnetite are proposed as essential components of iron mineral containing sensory dendrites. These dendrites in the inner lining of the upper beak of various bird species [1] are the first candidate structures for an avian magnetic field receptor. Our new concept of magnetoreception based on synchrotron radiation microscopic X-ray-fluorescence analysis (microXRF) and X-ray absorpt...

On the ‘centre of gravity’ method for measuring the composition of magnetite/maghemite mixtures, or the stoichiometry of magnetite-maghemite solid solutions, via 57Fe Mössbauer spectroscopy

We evaluate the application of 57Fe Mössbauer spectroscopy to the determination of the composition of magnetite (Fe3O4)/maghemite (γ-Fe2O3) mixtures and the stoichiometry of magnetite-maghemite solid solutions. In particular, we consider a recently proposed model-independent method which does not rely on a priori assumptions regarding the nature of the sample, other than that it is free of othe...

Arsenic and chromium removal by mixed magnetite-maghemite nanoparticles and the effect of phosphate on removal.

Adsorption of arsenic and chromium by mixed magnetite and maghemite nanoparticles from aqueous solution is a promising technology. In the present batch experimental study, a commercially grade nano-size 'magnetite', later identified in laboratory characterization to be mixed magnetite-maghemite nanoparticles, was used in the uptake of arsenic and chromium from different water samples. The inten...

Aging effects in the electrokinetics of colloidal iron oxides.

We analyze in this contribution the effect of aging on the electrokinetic properties of magnetite (Fe(3)O(4)) and hematite (alpha-Fe(2)O(3)). In both cases, high-purity commercial samples and monodisperse synthetic particles were studied. Commercial magnetite showed a rather erratic dependence of its electrophoretic mobility u(e) with the concentration of NaCl. Furthermore, sufficient concentra...

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