Shaped excitation pulses can replace the non-selective hard pulses typically used in a one-pulse measurement to achieve selective excitation. Another method of achieving selective excitation is the gradient spin echo using a selective 180° pulse. This technique is demonstrated in the figure below. A non-selective hard 90°x pulse is first given followed by a pair of identical pulsed field gradients sandwiching a soft selective 180° pulse about the y axis. The hard 90° pulse rotates all spin vectors onto the -y axis. During the first gradient pulse the spin vectors dephase and evolve according to their offset frequencies. The soft 180°y pulse flips a single resonance 180° about the y axis leaving all other resonances untouched. During the second gradient pulse, the "selected" resonance is rephased and its offset frequency evolution is refocused. The unselected resonances dephase more and continue to evolve according to their offset frequencies. The receiver is then turned on to collect the FID of the "selected" resonance, all others are dephased and therefore suppressed. This is demonstrated in the figure below which shows 1H NMR spectra for a mixture of methylence chloride and acetone. The bottom trace shows a standard one-pulse measurement. The middle and top traces show results from a selective gradient spin echo measurement with the selective 180° pulse set for methylene chloride and acetone, respectively.
NMR Excitation, Dephasing and Spin Echoes
NMR Excitation, Dephasing and Spin Echoes
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NMR Excitation, Dephasing and Spin Echoes
This short animation shows the process of NMR excitation in the laboratory and the rotating frame, as well as the dephasing that occurs from field inhomogeneity and the formation of the Hahn spin echo. Please credit (c)2010 Mark Cohen (mscohen@ucla.edu) during re-use.
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Orientation Selective DEER Measurements on Vinculin Tail at X-Band Frequencies Reveal Spin Label Orientations
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Publication year: 2012
Source: Journal of Magnetic Resonance, Available online 8 January 2012</br>
Christoph*Abé, Daniel*Klose, Franziska*Dietrich, Wolfgang H.*Ziegler, Yevhen*Polyhach, ...</br>
Double electron electron resonance (DEER) spectroscopy has been established as a valuable method to determine distances between spin labels bound to protein molecules. Caused by selective excitation of molecular orientations DEER primary data also depend on the mutual orientation of...
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Frequency-selective heteronuclear dephasing and selective carbonyl labeling to deconvolute crowded spectra of membrane proteins by magic angle spinning NMR.
Frequency-selective heteronuclear dephasing and selective carbonyl labeling to deconvolute crowded spectra of membrane proteins by magic angle spinning NMR.
Frequency-selective heteronuclear dephasing and selective carbonyl labeling to deconvolute crowded spectra of membrane proteins by magic angle spinning NMR.
J Magn Reson. 2011 Mar 17;
Authors: Traaseth NJ, Veglia G
We present a new method that combines carbonyl-selective labeling with frequency-selective heteronuclear recoupling to resolve the spectral overlap of magic angle spinning (MAS) NMR...
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04-13-2011 11:57 PM
Frequency-Selective Heteronuclear Dephasing and Selective Carbonyl Labeling to Deconvolute Crowded Spectra of Membrane Proteins By Magic Angle Spinning NMR
Frequency-Selective Heteronuclear Dephasing and Selective Carbonyl Labeling to Deconvolute Crowded Spectra of Membrane Proteins By Magic Angle Spinning NMR
Publication year: 2011
Source: Journal of Magnetic Resonance, In Press, Accepted Manuscript, Available online 17 March 2011</br>
Nathaniel J., Traaseth , Gianluigi, Veglia</br>
We present a new method that combines carbonyl-selective labeling with frequency-selective heteronuclear recoupling to resolve the spectral overlap of magic angle spinning (MAS) NMR spectra of membrane proteins in fluid lipid membranes with broad lines and...
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03-18-2011 06:43 AM
[NMR paper] Highly selective excitation in biomolecular NMR by frequency-switched single-transiti
Highly selective excitation in biomolecular NMR by frequency-switched single-transition cross-polarization.
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J Am Chem Soc. 2002 Mar 13;124(10):2076-7
Authors: Ferrage F, Eykyn TR, Bodenhausen G
A new method for selective excitation in biomolecular 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...
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11-24-2010 08:49 PM
[NMR paper] Spin-state-selective TPPI: a new method for suppression of heteronuclear coupling con
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J Magn Reson. 1999 Aug;139(2):443-6
Authors: Schulte-Herbrüggen T, Briand J, Meissner A, Sřrensen OW
A novel multidimensional NMR pulse sequence tool, spin-state-selective time-proportional phase incrementation (S(3) TPPI), is introduced. It amounts to application of...
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11-18-2010 08:31 PM
Introductory NMR & MRI: Video 06: Spin echoes, CPMG and T2 relaxation
Introductory NMR & MRI: Video 06: Spin echoes, CPMG and T2 relaxation
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Introductory NMR & MRI: Video 06: Spin echoes, CPMG and T2 relaxation
Paul Callaghan gives an introduction to NMR and MRI. This is the 6th video of a 10 episode series produced by Magritek Ltd.
From: magritek
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Self-diffusion in Polymer Systems studied by Magnetic Field-Gradient Spin-Echo NMR Me
Self-diffusion in Polymer Systems studied by Magnetic Field-Gradient Spin-Echo NMR Methods
Publication year: 2010
Source: Progress in Nuclear Magnetic Resonance Spectroscopy, In Press, Accepted Manuscript, Available online 13 April 2010</br>
Harald, Walderhaug , Olle, Söderman , Daniel, Topgaard</br>
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