Derk Joester, Northwestern University, USA

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Derk Joester from Northwestern University, will give a conference entitled "Chemical Imaging of Tooth Biominerals: From Nanoscale Gradients to Functional Properties" on Thursday, September 19 at 11h00, room Pierre Cotton

Abstract : Tooth biominerals are among the hardest, most wear resistant biological materials. Optimized to withstand the forces of mastication and the challenging chemical environment of the oral cavity, they are hierarchically structured, organic/inorganic nanocomposites. For example, the radula teeth of the chiton are capped with a composite made of magnetite and a nano-fibrous chitin that allows them to excavate rock. Human tooth enamel is composed of hydroxylapatite crystallites, thousands of which are bundled into rods that are organized in a three-dimensional weave; this provides great fracture resistance and a much-enhanced fatigue life. I will discuss how chemical imaging, using UV-laser pulsed atom probe tomography (APT), synchrotron scanning Mössbauer spectroscopy (SMS), and advanced electron and X-ray imaging approaches have given us remarkable new insights into the chemistry of organic/inorganic interfaces, grain boundaries, intergranular phases, and complex dopant gradients that are integral to the mechanical properties of teeth and their resistance to corrosion.

Contact :
Derk Joester
Materials Science and Engineering
Northwestern University
IL 60208, USA