Structural Analysis of Collagen Fibrils in Rat Skin Based on Small-Angle X-Ray-Diffraction Pattern

Abstract

Elastic neutron scattering experiments were carried out to investigate the magnetic structure and the critical behaviour of the mixed triangular antiferromagnetic system CsMn(Br 0.19 I 0.81 ) 3 , for which our previous magnetic measurement revealed the macroscopic anisotropy to be negligible. It is found that in the ordered state below T N = 8.29 K, the spin planes in which the spins lie with the 120 • structure are tilted from the basal plane, and that the average of the tilting angle φ is evaluated as cos 2 φ = 0.362, i.e. φ = 53 • . This result suggests that the present system is almost at the Heisenberg limit for the interaction. The critical exponent for the sublattice magnetization is obtained as β = 0.28 ± 0.02, which is in agreement with the value predicted for the chiral Heisenberg universality class.

Polymorphism of stable collagen fibrils

“…skin, interstitial stroma, and nerve and tendon sheaths. They have a slightly shorter D-period, consistent with the projective coupling hypothesis 34,42 . Despite their similarity of surface twist, in each tissue helicoidal fibrils exhibit a different unimodal radius -from 0.015 µm to 0.050 µm 34 .…”

“…While we have assumed that the radial and longitudinal structures are decoupled, a simple projective-coupling has been proposed in the literature 34,42 , corresponding to the D-band period being reduced by a factor of cos(ψ) due to non-zero twist. For our nonlinear double-twist model, the question immediately arises about how a single D-band spacing can represent a continuously varying twist, ψ(qr).…”

Structure of Type I and Type III Heterotypic Collagen Fibrils: An X-Ray Diffraction Study

“…Several angles have been reported in the literature for such helicoidal fibrils, with the data coming mainly from electron microscopy: 9° ( Folkhard et al, 1987); 12° (Brodsky and Eikenberry, 1982); 12-13° (Itoh et al, 1996); 14 -17° (Katz and David, 1992); 18° (Ruggeri et al, 1979). X-ray diffraction provides strong evidence for molecular inclination and is capable of estimating the variability of inclination angle within an assembly of fibrils.…”

“…Several theories have been reported as to how this tilting occurs, for example, as a consequence of molecular displacement through intermolecular crosslinking (Mechanic et al, 1987;Itoh et al, 1996).…”