Determination of the electron density profile of the nerve myelin membrane in different states taking paracrystalline lattice distortions into account.
Recent investigations point to the presence of paracrystalline lattice disorder in the nerve myelin in the swollen, fixed and to some extent also in the native state. This leads to the distortion of the Q-function of the membrane stack and the Q0-function of the unit cell, which can be experimentally isolated through swelling. Representing the distance statistics between neighbouring membranes and the electron density distribution of the single membrane with Gaussian functions, the Q-function can be expressed analytically as a convolution polynomial of the electron density, its mirror image and the distance statistics functions. Fitting this model Q-function to the experimental Q-function obtained by the inverse Fourier transformation of the scattered intensity, one can determine the optimal parameters of the electron density distribution and the distance statistics functions. The elimination of the distance fluctuations between neighbouring membranes permits the calculation of the undistorted Q-function or the Q0-function. The Fourier Analytical Deconvolution of the undistorted Q0-function enables a unique determination of the double membrane profile, thus a unique phase determination.
D015502:Absorptiometry, Photon; D000818:Animals; D001001:Anura; D008566:Membranes; D009186:Myelin Sheath; D014961:X-Ray Diffraction