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Re: Are dinosaurs really reptiles? (2)



Martin Baeker writes:

Just a minor note: AFAIK, in general beta-Keratin is stiffer (larger
young's modulus, about 5-8GPa, compared to 2-3GPa or so for
alpha-Keratin) than alpha-Keratin due to the beta-structure (if you
strain it, you strain the covalent bonds along the backbone chain of
the molecule, whereas in alpha-keratin you start by straining the
hydrogen bonds along the helix.)

I believe beta-keratin is also more waterproof. Reptiles need a good waterproof skin to stop from drying out, whereas us mammals with our gross sweaty glandular skin require something a bit more water permeable.



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Dann Pigdon
GIS / Archaeologist              http://geo_cities.com/dannsdinosaurs
Melbourne, Australia             http://heretichides.soffiles.com
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