Diffusion Magnetic Resonance Imaging (dMRI) can be used to measure a time-dependent effective diffusion coefficient that can in turn reveal information about the tissue geometry. Recently a mathematical model for the time-dependent effective diffusion coefficient was obtained using homogenization techniques after imposing a certain scaling relationship for the time, the biological cell membrane...

When a protein unfolds in the cell, its diffusion coefficient is affected by its increased hydrodynamic radius and by interactions of exposed hydrophobic residues with the cytoplasmic matrix, including chaperones. We characterize protein diffusion by photobleaching whole cells at a single point, and imaging the concentration change of fluorescent-labeled protein throughout the cell as a functio...

Laser scanning confocal microscopy combined with fluorescence recovery after photobleaching is an effective tool to measure the diffusion coefficients of macromolecules in cross-linked hydrogels and polymer solutions. In this study, the effects of enzyme treatment on the diffusion of macromolecules (FITC-dextran) in guar solutions and titanium-guar hydrogels are examined. Enzyme treatment with ...

observed, and D ∆ is the (time-dependent) diffusion coefficient measured at this diffusion time. Short-time-scale measurements of hyperpolarized He diffusion in the human lung typically use diffusion times between 1 and 2 ms. At this time scale, the He diffusion coefficient in normal lung airspaces is approximately 0.2 cm/s. Thus these measurements probe a length scale of approximately 350-500 ...

deterioration of concrete structures in the gulf region is a serious problem. penetration of chloride ion into concrete is responsible for such early deterioration. determination of chloride diffusion coefficient is an effective way to predict the service life of concrete structures. in order to investigate the performance of concrete mixtures in such environments, ordinary and silica fume conc...

The diffusion coefficient of fluorescein in detached cilia of Xenopus laevis olfactory receptor neurons was measured using spatially-resolved FRAP, where the dye along half of the ciliary length was photobleached and its spatiotemporal fluorescence redistribution recorded. Fitting a one-dimensional numerical simulation of diffusion and photobleaching for 35 cilia resulted in a mean value of the...

Restrictions to diffusion result in the dispersion of the bulk diffusion coefficient. We derive the exact universal high-frequency behavior of the diffusion coefficient in terms of the surface-to-volume ratio of the restrictions. This frequency dependence can be applied to quantify structure of complex samples with NMR using oscillating field gradients and static-gradient CPMG. We also demonstr...

background diffusion-weighted imaging (dwi) is a form of magnetic resonance imaging (mri) based on measuring the random brownian motion of water molecules within the biological tissues and is particularly useful in tumor characterization. objectives the purpose of this study was to evaluate the diagnostic value of dw mri and the apparent diffusion coefficient (adc) for preoperative grading of a...