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SUMMARY:IMX Talks - Hierarchical structure and functionality of the min
 eralized tissue of shark vertebral centra
DTSTART:20251219T100000
DTEND:20251219T110000
DTSTAMP:20260921T175007Z
UID:7f83bac362f1336447c5dbbeb149cb326f8f6d989a64a1d961034a18
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Stuart R. Stock\, Northwestern University\, Chicago USA\n
 Shark vertebral bodies (centra) consist of cartilage which is reinforced b
 y nanoparticles of bioapatite mineral. The centra possess remarkable resis
 tance to millions of cycles of in vivo strains exceeding 4-8%. These strai
 ns are enormous for a mineralized tissue\, and the centra have evolved to 
 achieve this performance through a hierarchy of structures spanning dimens
 ions from centimeters to nanometers. Since 2019\, there has been significa
 nt progress in characterizing the various structures\, and results will be
  presented from larger to smaller spatial dimensions\, i.e.\, macro-\, mic
 ro- and nano-scales. Laboratory microComputed Tomography (microCT) with 15
 -20 µm volume elements (voxels) revealed complex microstructure related t
 o centra’s growth processes. Relatively low resolution\, 3D energy dispe
 rsive diffraction mapping uncovered zones with different (mineral) crystal
 lographic texture. At the one micrometer level\, synchrotron microCT with 
 0.67 µm voxels quantified 3D centra microstructures: these consist of an 
 interconnected array of 5-15 µm thick mineralized plates (trabeculae) sep
 arated by a similarly-sized continuous network of unmineralized soft tissu
 e and fluid. Synchrotron microCT observation of in situ loading of small b
 locks demonstrated that the deformation is accommodated by rotation/deflec
 tion of the centra’s trabeculae. Synchrotron microbeam diffraction of sm
 all blocks during in situ loading revealed the mineral phase is carrying o
 nly small strains. Finally\, prospects for continuing studies are discusse
 d.\n 
LOCATION:MXF 312 https://plan.epfl.ch/?room==MXF%20312
STATUS:CONFIRMED
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