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Friedrich-Wilhelm-Lübke-Koog, Germany

Bruning B.,Laue Langevin Institute | Bruning B.,Institute For Rontgenphysik | Bruning B.,Helmholtz Center Berlin | Rheinstadter M.C.,McMaster University | And 5 more authors.
European Physical Journal E | Year: 2010

We have studied the packing and collective dynamics of the phospholipid acyl chains in a model membrane composed of 1,2-dimyristoyl-sn-glycero-3- phosphatidylcholine (DMPC) and cholesterol in varied phase state. After a structural characterization of this two-component model bilayer using X-ray reflectivity, we have carried out coherent inelastic neutron scattering to investigate the chain dynamics. Both DMPC/cholesterol membranes exhibited much sharper and more pronounced low-energy inelastic excitations than a pure DMPC membrane. In the high-energy regime above 10meV, the insertion of cholesterol into the membrane was found to shift the position of the inelastic excitation towards values otherwise found in the pure lipids gel phase. Thus, the dissipative collective short-range dynamics of the acyl chains is strongly influenced by the presence of cholesterol. © 2010 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.

Nicolas J.-D.,Institute For Rontgenphysik | Reusch T.,Institute For Rontgenphysik | Osterhoff M.,Institute For Rontgenphysik | Sprung M.,German Electron Synchrotron | And 4 more authors.
Journal of Applied Crystallography | Year: 2014

Time-resolved coherent X-ray diffraction experiments of standing surface acoustic waves, illuminated under grazing incidence by a nanofocused synchrotron beam, are reported. The data have been recorded in stroboscopic mode at controlled and varied phase between the acoustic frequency generator and the synchrotron bunch train. At each time delay (phase angle), the coherent far-field diffraction pattern in the small-angle regime is inverted by an iterative algorithm to yield the local instantaneous surface height profile along the optical axis. The results show that periodic nanoscale dynamics can be imaged at high temporal resolution in the range of 50 ps (pulse length).

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