Structure of Organosilicon Dendrimers of Higher Generations

The structure of organosilicon dendrimers of the ninth generation with the four-functional core and butyl terminal groups has been studied by small-angle neutron scattering. It has been demonstrated that the dendrimers are monodisperse objects with an anisometric shape. The partial volume and the average scattering density have been determined using the contrast variation technique. It has been shown that the dendrimers under study are identical in overall sizes and scattering density distribution. It has been revealed that 20% of the overall volume of the dendrimer is accessible for the penetration of the solvent. The distribution of the scattering length density in the dendrimers has been simulated and reconstructed using the Monte Carlo method, and a change in the excluded volume for different contrasts has been revealed. The specific features of the spatial structure of organosilicon dendrimers of higher generations have been discussed

X-ray scattering and volumetric P-V-T studies of the dimyristoylphosphatidylcholine-water system

The results of a study of the temperature and pressure dependence of isothermal compressibility of dimyristoylphosphatidylcholine (DMPC) are presented. The data were obtained using a small-angle X-ray scattering instrument in the Institute of Synthetic Polymer Materials (Moscow, Russia) and a device designed in the Laboratory of Neutron Physics, Joint Institute for Nuclear Research (Dubna, Russia), for studying the liquid systems by a volumetric P-V-T method. The minute baric investigation of the region of the main phase transition (transition from the gel phase into the liquid crystalline phase) was carried out. The points of the main phase transition were determined, and the phase diagram of DMPC was plotted over the pressure range of 1-800 bar at temperature from 24 to 35 degrees C