Metallogenomics and biological X-ray absorption spectroscopy

X-ray Absorption Spectroscopy

X-ray absorptioń spectroscopy, today widely used as a tool for structural investigations, is described. Theoretically it is shown that above an absorption edge the absorption coefficient is well approximated by a sum of terms, each one describing a particular path followed by the photoelectron outgoing from the atom. Such geometrical feature allows to use X-ray absorption spectroscopy for struc...

X-ray Absorption Spectroscopy

1.59.1 PHYSICS OF X-RAY ABSORPTION 1 1.59.1.1 X-ray Absorption Edges 2 1.59.1.2 X-ray Fluorescence 3 1.59.1.3 Measurement of X-ray Absorption Spectra 3 1.59.2 EXTENDED X-RAY ABSORPTION FINE STRUCTURE 6 1.59.2.1 Theoretical Description of EXAFS Spectra 6 1.59.2.1.1 Single scattering 6 1.59.2.1.2 Multiple scattering 8 1.59.2.1.3 Other corrections to the EXAFS equation 9 1.59.2.2 Programs for Calc...

X-Ray Absorption Spectroscopy of Light Elements* in Biological Systems

X-Ray Absorption Spectroscopy Imaging of Biological Tissues

X-ray absorption spectroscopy (XAS) is proving invaluable in determining the average chemical form of metals or metalloids in intact biological tissues. As most tissues have spatial structure, there is great additional interest in visualizing the spatial location of the metal(loid) as well as its chemical forms. XAS imaging gives the opportunity of producing maps of specific chemical types of e...

Biological Calcification : Investigation by X-ray Absorption Spectroscopy

Model compounds which resemble the calcium phosphates deposited in biological systems have been synthesised, characterised by a variety of physical techniques and their EXAFS spectra recolded abo~c, the calcium K edge. The spectrum of one of the compounds, hydroxyapatite, has been ;in:~iysecl and the results used to aid the analysis of spectra from related compounds. Spectra recorded above the ...