Collecting 2D or 3D NMR data can be very time consuming. The indirect dimension of a 2D experiment is sampled linearly via the t1 increments in the pulse sequence. An FID must be collected for every single linearly spaced t1 increment. In the interest in collecting 2D or 3D NMR data in a more time efficient manner, a great deal of effort is made towards faster data collection techniques. While some of these methods are based on spatial selectivity, others are based on sparse sampling techniques in the indirect dimensions of nD NMR sequences. One such sparse sampling method, given the name non-uniform sampling (NUS), samples a sub-set of the indirect dimension in a random (or weighted random) manner and then predicts the uncollected data based on the data sampled, in much the same way data are predicted in the forward and backward linear prediction methods. The reconstructed data is then used for the indirect Fourier transforms. A comparison of the conventional and non-uniform data sampling methods is illustrated in the figure below.
Collecting only a fraction of FID's reduces the experiment time by the same fraction. The figure below shows a superposition of partial 600MHz 1H-13C HSQC spectra of a D2O solution of sucrose.
All of the spectra were collected with 2 scans per increment using a 1.5 second recycle time. The lower spectrum in black was collected conventionally with 256 increments in 15 minutes. The middle spectrum in blue was collected conventionally with 64 increments in 3.75 minutes. The top spectrum in purple was collected using NUS with 25% of 256 increments (i.e. 64 increments) collected in 3.75 minutes. A comparison of the two conventionally collected data sets shows the expected loss in F1 resolution with the 4-fold reduction in experiment time by reducing the number of increments by a factor of 4. The bottom (black) conventional spectrum and the top (purple) NUS spectrum are however virtually indistinguishable despite the 4-fold reduction in experiment time for the NUS spectrum. NUS is a very valuable technique for reducing experiment times without sacrificing resolution.
[NMR paper] Non-uniform sampling of NMR relaxation data.
Non-uniform sampling of NMR relaxation data.
Related Articles Non-uniform sampling of NMR relaxation data.
J Biomol NMR. 2016 Feb 4;
Authors: Linnet TE, Teilum K
Abstract
The use of non-uniform sampling of NMR spectra may give significant reductions in the data acquisition time. For quantitative experiments such as the measurement of spin relaxation rates, non-uniform sampling is however not widely used as inaccuracies in peak intensities may lead to errors in the extracted dynamic parameters. By systematic reducing the coverage...
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02-06-2016 03:10 PM
Non-uniform sampling of NMR relaxation data
Non-uniform sampling of NMR relaxation data
Abstract
The use of non-uniform sampling of NMR spectra may give significant reductions in the data acquisition time. For quantitative experiments such as the measurement of spin relaxation rates, non-uniform sampling is however not widely used as inaccuracies in peak intensities may lead to errors in the extracted dynamic parameters. By systematic reducing the coverage of the Nyquist grid of 15N Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion datasets for four different proteins and performing a full...
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02-05-2016 02:38 PM
[NMR paper] Non-Uniform Sampling and J-UNIO Automation for Efficient Protein NMR Structure Determination.
Non-Uniform Sampling and J-UNIO Automation for Efficient Protein NMR Structure Determination.
Related Articles Non-Uniform Sampling and J-UNIO Automation for Efficient Protein NMR Structure Determination.
Chemistry. 2015 Jul 28;
Authors: Didenko T, Proudfoot A, Dutta SK, Serrano P, Wüthrich K
Abstract
High-resolution structure determination of small proteins in solution is one of the big assets of NMR spectroscopy in structural biology. Improvements in the efficiency of NMR structure determination by advances in NMR experiments...
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08-02-2015 07:10 AM
[NMR paper] Performance tuning non-uniform sampling for sensitivity enhancement of signal-limited biological NMR.
Performance tuning non-uniform sampling for sensitivity enhancement of signal-limited biological NMR.
Related Articles Performance tuning non-uniform sampling for sensitivity enhancement of signal-limited biological NMR.
J Biomol NMR. 2014 Mar 29;
Authors: Palmer MR, Wenrich BR, Stahlfeld P, Rovnyak D
Abstract
Non-uniform sampling (NUS) has been established as a route to obtaining true sensitivity enhancements when recording indirect dimensions of decaying signals in the same total experimental time as traditional uniform...
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04-01-2014 02:47 PM
[NMR paper] Time-resolved multidimensional NMR with non-uniform sampling.
Time-resolved multidimensional NMR with non-uniform sampling.
Time-resolved multidimensional NMR with non-uniform sampling.
J Biomol NMR. 2014 Jan 17;
Authors: Mayzel M, Rosenlöw J, Isaksson L, Orekhov VY
Abstract
Time-resolved experiments demand high resolution both in spectral dimensions and in time of the studied kinetic process. The latter requirement traditionally prohibits applications of the multidimensional experiments, which, although capable of providing invaluable information about structure and dynamics and almost unlimited...
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01-18-2014 11:31 AM
[NMR analysis blog] Non Uniform Sampling (NUS) NMR Processing
Non Uniform Sampling (NUS) NMR Processing
Background
In the last few years, Non-Uniform Sampling (NUS) has emerged as a very powerful tool to significantly speed up the acquisition of multidimensional NMR experiments due to the fact that only a subset of the usual linearly sampled data in the Nyquist grid is measured.
Unfortunately, this fast acquisition modality introduces a new challenge as the normal Fourier Transform will fail and consequently, special processing techniques are required.
A number of sophisticated methods have been proposed for reconstructing sparsely sampled 2D...
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12-21-2013 03:15 PM
An analysis of NMR sensitivity enhancements obtained using non-uniform weighted sampling, and the application to protein NMR
An analysis of NMR sensitivity enhancements obtained using non-uniform weighted sampling, and the application to protein NMR
June 2012
Publication year: 2012
Source:Journal of Magnetic Resonance, Volume 219</br>
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Non-uniform weighted sampling (NUWS) is a sampling strategy, related to non-uniform sampling (NUS) in the limit of long acquisition times, in which each indirect increment of a multidimensional spectrum is sampled multiple times according to some weighting function. As the spectrum is fully sampled it can be processed in a conventional manner by the...
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02-03-2013 10:13 AM
An analysis of NMR sensitivity enhancements obtained using non-uniform weighted sampling, and the application to protein NMR
An analysis of NMR sensitivity enhancements obtained using non-uniform weighted sampling, and the application to protein NMR
Publication year: 2012
Source:Journal of Magnetic Resonance</br>
Christopher A. Waudby, John Christodoulou</br>
Non-uniform weighted sampling (NUWS) is a sampling strategy, related to non-uniform sampling (NUS) in the limit of long acquisition times, in which each indirect increment of a multidimensional spectrum is sampled multiple times according to some weighting function. As the spectrum is fully sampled it can be processed in a conventional...
Non-uniform Sampling (NUS)
Linear Mode
