strong diffraction ring, often quoted as thea-chitin
signature is found at 0.338nm (Fig. 2a) whereas a
similar ring occurs at 0.324nm in b-chitin; (ii) an
inner ring at 0.918nm in b-chitin is sensitive to
hydration, moving to 1.16nm in the presence of
liquid water, whereas a similar strong inner ring at
0.943nm ina-chitin is insensitive to hydration.