Pressure Induced Hydration Dynamics of Membranes

Pressure-jump initiated time-resolved x-ray diffraction studies of dynamics of the hydration of the hexagonal phase in biological membranes show that (i) the relaxation of the unit cell spacing is non-exponential in time; (ii) the Bragg peaks shift smoothly to their final positions without significant broadening or loss in crystalline order. This suggests that the hydration is not diffusion limited but occurs via a rather homogeneous swelling of the whole lattice, described by power law kinetics with an exponent $\beta = 1.3 \pm 0.2$.Comment: REVTEX 3, 10 pages,3 figures(available on request),#

Overlayer-induced ordering of the disordered surface monolayer in Langmuir-Blodgett multilayer thin films

X-ray scattering results from Langmuir-Blodgett thin films demonstrate that the surface monolayer at the multilayer-air interface is disordered and that ordering of the surface monolayer can be induced by the deposition of an additional monolayer. The data was analysed by a novel refinement technique which does not assume a centrosymmetric structure or the existence of a unit cell.On présente une expérience de diffusion des rayons X par des films de Langmuir-Blodgett. Les résultats montrent que la monocouche de surface à l'interface film multicouches/air est désordonnée, et qu'elle peut être réordonnée par dépôt d'une monocouche supplémentaire. Les données sont analysées au moyen d'une nouvelle technique qui calcule la fonction d'autocorrélation du profil du film sans supposer la structure centrosymétrique et sans postuler l'existence d'une cellule unité