More Fracture Resistance And Warm Up

Ok, bone differs from rock, There is a reaction to warm up stress in bone at the molecular level. How's it work? I gave this a shot last post, but, still unsatisfied, and more Google and again was reminded, they're selling these articles. But, I came up with this summary of Hansma's work:

(published 7/05)
"FUNDAMENTAL DISCOVERY ABOUT THE FRACTURE OF HUMAN BONE: IT'S ALL IN THE 'GLUE'

A startling discovery about the properties of human bone has been made by scientists at the University of California, Santa Barbara.
The scientists describe their results--finding a sort of "glue" in human bone--in the cover story of ...Nature Materials. It describes how healthy bone resists fracture and how unhealthy bone fractures at the molecular level. Included with the article are highest resolution images of bone ever published which reveal the location of the adhesive or "glue" that hold together mineralized collagen fibrils (protein fibers) of bone.

The glue appears to contain "springs" that uncoil when the bone is stressed, helping the bone to absorb shock. When the stress is relaxed, they coil back to their original structure.

...the scientists spent several years tracking down where the glue was located in bone and how it worked.

Before this research, it was well known that the mechanical properties of bone depended on mineral particles and on collagen fibrils, said Hansma. The picture of bone was that it consisted of these collagen fibrils coated with tiny mineral crystals only a few atoms thick. What we found is that there is a glue in bone that holds these mineralized collagen fibrils together, and this glue works along the same principles ...found in abalone shells. This glue involves sacrificial bonds (with hidden length) that uncoil when bone is stressed.


Image: Individual collagen fibrils are held together with glue filaments (arrows).

It's especially exciting ...he described the discovery of "molecular shock absorbers" providing a kind of self-healing glue holding biological mineralized structures together when studying the abalone shell...

He noted that these mechanisms give young healthy bone its resiliency and resistance to fracture, and actually help heal microcracks after they're formed..."

Training:
Questionable scheduling this week has put us a little bit behind. We're breezing them tonight, and then Eureka Sunday. Here is Art's work:
7/17/07 Tues. 5 x 1f riderless 90% speed with oldster. ten min walk under tack.
7/18/07 Wed. rest.
7/19/07: Thurs. riderless 5f warm up + 2 miles riderless very slow. 10 min walk under tack.