title: Electron beam damage studies of synthetic 6-line ferrihydrite and ferritin molecule cores within a human liver biopsy.
abstract: In order to achieve an accurate understanding of the crystal structure of 6-line ferrihydrite (6LFh) and ferritin molecule cores within a human liver biopsy using transmission electron microscopy (TEM), electron beam damage should be considered. For the case of 6LFh, the electron energy loss near-edge structure (ELNES) of core ionisation edges in the electron energy loss spectrum (EELS) combined with multiple linear least-square (MLLS) fitting of reference spectra together with analysis of selected area electron diffraction (SAED) patterns suggests that the iron in 6LFh is solely octahedrally coordinated Fe3+. With increasing electron dose, an increasing percentage of this octahedrally coordinated Fe3+ migrates to tetrahedral sites. When the dose exceeds 3 x 10(8) electrons/nm2, Fe2+ is found to be present in the material. This method also indicates that the iron in ferritin molecule cores within a human liver biopsy is the same as in 6LFh, entirely Fe3+ in octahedral coordination with oxygen. Again the percentage of octahedrally coordinated Fe3+ decreases as the accumulated electron dose increases and Fe2+ is produced in the liver biopsies when the electron dose exceeds 10(6)electrons/nm2.
authors.affiliation: Institute for Materials Research, University of Leeds, Leeds LS2 9JT, UK. sms2yp@leeds.ac.uk
authors.forename: Y
authors.initials: Y
authors.lastname: Pan
authors.forename: A
authors.initials: A
authors.lastname: Brown
authors.forename: R
authors.initials: R
authors.lastname: Brydson
authors.forename: A
authors.initials: A
authors.lastname: Warley
authors.forename: A
authors.initials: A
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: Powell
mesh_terms: D000328:Adult; D001706:Biopsy; D004583:Electrons; D005290:Ferric Compounds / Q000737:chemistry*; D005293:Ferritins / Q000737:chemistry* / Q000648:ultrastructure; D006801:Humans; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008297:Male; D046529:Microscopy, Electron, Transmission
chemical_list: D005290:Ferric Compounds; C092844:ferric oxyhydroxide; D005293:Ferritins