Berry dephasing due to diffusion in nuclear quadrupole resonance
Chemical Physics Letters Elsevier 247:3 (1995) 215-220
Application of Maximum Entropy Methods to Three-Dimensional NMR Spectroscopy
Journal of Magnetic Resonance, Series B 101:2 (1993) 218-222
Analysis of COSY cross peaks by deconvolution of the active splittings
Journal of Magnetic Resonance - Series A 101:2 (1993) 162-169
Abstract:
Various numerical techniques for alleviating crowding in two-dimensional NMR correlation spectra are investigated with a view to facilitating the measurement of spin-spin coupling constants. The following strategy for the analysis of cross sections through COSY cross peaks is developed: The active coupling constant is determined by J doubling (McIntyre and Freeman, J. Magn. Reson.96, 425, 1992). The active splitting is then removed (J deconvolution) by the maximum-entropy method. Estimates of the passive coupling constants are next obtained from the deconvolved spectrum. Finally, the values of all coupling constants are refined, if necessary, by model fitting to the original spectrum. This approach is shown to be successful for complex, congested cross peaks, whose multiplet structures are far from obvious. © 1993 by Academic Press, Inc.Suppression of artifacts in the phase-modulated rotating-frame imaging experiment using the maximum-entropy method
Journal of Magnetic Resonance (1969) 98:1 (1992) 73-80
Abstract:
Phase-modulated rotating-frame imaging, a technique used. for the detection of localized metabolites in vivo, is usually implemented in a less than ideal manner because of the practical constraints imposed by the human or animal sample. As a consequence, the spectra obtained by Fourier transformation contain artifacts which distort or obscure the genuine spectral features. An attractive alternative is to use the maximum-entropy method to process the data, incorporating the time-domain response of the nuclear spins predicted by the Bloch equations. Here we demonstrate this approach using simulated data, data from phantoms, and data from the human liver and chest wall. We show that artifacts in the Fourier-transform spectra arising from off resonance effects, imperfect pulse angles, and truncation can be effectively avoided by maximum-entropy processing. © 1992.The maximum entropy method and fourier transformation compared
Journal of Magnetic Resonance (1969) 92:2 (1991) 276-292