The cubic oxygen sub-lattices that form the backbone of the ice VII structure persist to pressures of at least 128 GPa; this pressure is substantially higher than that at which water loses its molecular character entirely, forming ice X . In high pressure ices, protonic diffusion ( movement of protons around the oxygen lattice ) dominates molecular diffusion, an effect which has been measured directly.
32.
"' Intravoxel incoherent motion "'( IVIM ) imaging is a concept and a method initially introduced and developed by Le Bihan et al . to quantitatively assess all the microscopic translational motions that could contribute to the signal acquired with diffusion MRI . In biological tissue, these motions essentially are molecular diffusion of water and microcirculation of blood in the capillary network ( perfusion ).
