Double-quantum-filtered NMR spectra of 23 Na in bovine nasal cartilage tissue and its
constituents were measured. The presence of even-rank tensors was detected in the
cartilage tissue and in a suspension of collagen fibers, indicating anisotropic motion of the
sodium ions. Quantitative analysis of the spectra was performed by calculating the time
evolution of the second-and third-rank tensors by solving a modified Redfield equation.
Analytical expressions for the spectra were obtained. It is shown that the anisotropy stems …