th  - 1988 - 51st ENC Conference

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TAYLOR TRANSFORMATION OF 2D NMR "Um SERIES
FROM TIME DIMENSION TO POLYNOMIAL DIMENSION
FOR CONVENIENT DETERMINATION OF CROSS
RELAXATION RATES IN NOESY SPECTRA
Sven G. Hyberts* & Gerhard Wagner
Biophysics Research Division, IST; University of Michigan;
2200 Bonisteel Blvd; Ann Arbor, MI 48109
A series of 14 NOESY specra with 1;m values ranging from 10 ms to 75 ms, was
subject to a point-by-point Taylor transformation around l:m=0. This yields a
zero-order spectrum containing the diagonal and base-line offset, a 1st-order
spectrum containing only the cross relaxation rates and a 2nd-order spectrum
containing the spin-diffusion and Tl-relaxation effects. To improve the signal-
to-noise ratio we have truncated the Taylor expansion after the second order
term. The cross relaxation rate can now be determined directly by integration of
the desired cross-peak in the 1st-order spectrum. In the usual approach, the
selected cross-peak has to be integrated in each 2D spectrum and then, the
build-up curve has to be fitted to determine the cross relaxation rate. This is
quite labour intensive for a macromolecule with many cross-peaks preventing
the quantitative analysis of NOESY spectra in most structural work sofar. The
method proposed provides a more convenient measurement of the cross
relaxation Pates and may thus encourage quantitative analysis of NOESY
spectra.
- - lOS
I
EVALUATION OF DOUBLE TUNED CIRCUITS USED IN NMR: Toby Zens*
Varian Associates, Palo Alto, CA 94303
Double tuned circuits are frequently used in NMR probes as a
simple means of exciting and detecting nuclei in a single coil
device. General examples of different double tuned
will be examined in terms of efficiency and
application to NMR probes. Examples will include
used in CPMAS and surface coil probes.
151
circuits
practical
circuits