Bone Mechanics II

RR continues milking the Southwest Research Institute post(dated 2008 as it turns out):

8. PGE2 stands for "prostaglandin E2" one of several types of protaglandin--E1,E2, E3--frequently discussed in joint inflamation. Among several other chemical effects PGE2 is significant in"regulating calcium movement". (Wikepedia). You'd suspect the SW Research Institute researchers used PGE2 perhaps as a marker measurable in terms of volume within the bone matrix depending on level of stress/strain.

9. "The research goals are to quantify osteocyte deformation...from both fluid flow generated shear stress to substrate stretching."

There you have it folks. Substrate stretching! May we presume that in response to concussive forces the calcified matrix crystals at the atomic level contract and expand in response to stress. This was discussed here:

http://ratherrapid.blogspot.com/2008/08/signaling-and-methodology-of-breakage.html

10: "Bone Quality" = (a) bone mineral and organic constituents. (b) microarchitecture, (c) micro damage accumulation.

11. Bone quality is an increasingly recognized determinant of fracture risk.

12. "Bone strength" = bone density + bone quality. Unnecessary henceforth to rely on RR blog definitions. These researchers have defined things for us!!!

13. Bone mineral density is measurable and accounts for 70% of bone strength!!!

14. Bone fracture toughness (referred to on the blog as FR or fracture resistance) is significantly correlated to changes in porosity, microarchitecture, osteonal morphology, collagen integrity, and microdamage, all of which are measures of bone quality.

15. Current technology does not allow the nondestructive and non-invasive detection of bone micro damage...Current techniques require serial re sectioning and microscopic exam of bone specifmens. (presumably of just slaughtered cattle bones--the researchers here are using mouse bones.) They are using non-invasive Nuclear Magnetic Resonance imaging in their study "to predict cortical bone micro damage."

16. "Uncertainty and randomness inherently involved in the mechanics of skeletal structures".

Well--that is a lot of info. Regrettably that's it on the site, and we're never provided the results of their stress/strain PGE2 experiment. Much like Paul Hansma's site which I'm rechecking for new info, this site falls short of giving us final info but provides heretofore on this blog significant actual substance.