title: Extension of the Rorschach--Hazlewood theoretical model for spin-lattice relaxation in biological systems to low frequencies.
abstract: The water-biopolymer cross-relaxation model, proposed by H. E. Rorschach and C. F. Hazlewood (RH) [J. Magn. Reson. 70, 79 (1986)], explains the Larmor frequency dependence of T1 in many biological systems. However, the RH theory fails at low Larmor frequencies. In this paper, a more general version of the RH theory has been developed. This theory is valid at all frequencies. Use of the new expression for the spin-lattice relaxation rate (1/T1), earlier published experimental data in H2O/D2O bovine serum albumin, which had been measured over a wide frequency range (10 kHz to 100 MHz), were fitted over the entire frequency range. The agreement between theory and the experimental data is excellent. Theoretical expressions for the rotating-frame spin-lattice relaxation rate (1/T1(rho)) were also obtained.
authors.affiliation: Department of Physics, University of Utah, Salt Lake City 84112, USA.
authors.forename: A
authors.initials: A
authors.lastname: Hackmann
authors.forename: D C
authors.initials: DC
authors.lastname: Ailion
authors.forename: K
authors.initials: K
authors.lastname: Ganesan
authors.forename: G
authors.initials: G
authors.lastname: Laicher
authors.forename: K C
authors.initials: KC
authors.lastname: Goodrich
authors.forename: A G
authors.initials: AG
authors.lastname: Cutillo
mesh_terms: D000465:Algorithms; D000818:Animals; D002417:Cattle; D003903:Deuterium; D004578:Electron Spin Resonance Spectroscopy; D009682:Magnetic Resonance Spectroscopy; D008962:Models, Theoretical; D015203:Reproducibility of Results; D012709:Serum Albumin; D014867:Water
chemical_list: D012709:Serum Albumin; D014867:Water; D003903:Deuterium