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A novel NMR method characterizes slow motions in proteins by multiple refocusing of double- and zero-quantum coherences of amide protons and nitrogen-15 nuclei. If both nuclei experience changes in their isotropic chem. shifts because of internal motions o ...
Using optimized, asymmetric radiofrequency (RF) pulses for slice selection, the authors demonstrate that stimulated echo acquisition mode (STEAM) localization with ultra-short echo time (1 ms) is possible. Water suppression was designed to minimize sensiti ...
It is shown how transverse magnetization can be excited with a single low-power radiofrequency pulse consisting of a superposition of 2 frequency-modulated components. The phase dispersion obtained with this self-refocusing pulse is very small over bandwid ...
In NMR of quadrupolar spins with S >= 3/2, excitation and observation of multiple-quantum coherence is possible in the absence of scalar, dipolar, or quadrupolar splittings, in contrast to the widely accepted view that nonvanishing couplings are a prerequi ...
Five different types of expt. are described which make it possible to measure various relaxation rates of selected protons in crowded spectra of macromols. such as proteins: longitudinal spin-lattice relaxation rates rt = 1/T1, transverse relaxation rates ...
A novel approach to inversion recovery in NMR is described which combines adiabatic inversion with the observation of a spin echo refocused by a chirp pulse. This echo method allows one to generate in-phase magnetization over a broad range of frequencies. ...
A novel spin-echo expt. is proposed that uses semiselective Gaussian pulse cascades for refocusing in systems with homonuclear couplings. The expt. allows one to obtain evdience of differential T2 effects due to cross-correlation of proton chem. shift anis ...
It is shown by simulation and expt. that frequency-modulated "chirp" pulses are very effective for exciting multiple-quantum coherences over large bandwidths. Chirp pulses can be considered as an alternative to composite pulses to combat the effects of l ...
A comprehensive description is presented of the effects on two-spin coherences (i.e., superpositions of zero- and double-quantum coherences) of cross-correlation between the fluctuations of two different relaxation mechanisms in NMR (NMR). Dipole-dipole (D ...
A new method for selective excitation in biomol. NMR uses two-fold single-transition cross-polarization between protons and nitrogen-15 or carbon-13 nuclei. Switching the frequencies between the forward and backward transfer steps allows one to select a mu ...
