Cory and Ritchey* introduced a very simple, clever method to suppress background signals in 1988. Their method uses a composite pulse, consisting of a 90° and two 180° pulses with appropriate phase cycling, in place of a conventional 90° pulse. The phase cycled composite pulse is essentially a 90° pulse for all spins inside the coil and 0° for all spins outside of the coil. An example of its implementation is shown in the figure below. The bottom traces show the 11B [1H] NMR spectra for a dilute sample of NaBH4 and a "real" synthetic sample on the left and right, respectively. One can see an enormous background signal from both the NMR probe and the NMR tube. In the case of the "real" synthetic sample, the information from the spectrum is difficult or impossible to recover. The top traces show similar spectra acquired using the composite pulse. The only background signal remaining is that from the portion of the NMR tube inside the coil. This pulse sequence (without proton decoupling) is in the Bruker pulse program library called "zgbs". It is not exclusive to 11B.
D.G. Cory and W.M. Ritchey. Journal of Magnetic Resonance, 80, 128 (1988).
[KPWU blog] [PyMOL] gradient background color
gradient background color
Starting at *PyMOL 1.4, *single color for the background is no longer the only choice. By using 3 PyMOL commands, the gradient background color can be easily shown. The only thing users have to know is that command “ray” doesn’t support this gradient color yet. So if you type “ray” in the pymol terminal , http://stats.wordpress.com/b.gif?host=kpwu.wordpress.com&blog=76132&post=619&subd=kpwu&ref=&feed=1
Go to KPWU blog to read complete post.
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11-15-2011 11:36 PM
Expanding the utility of NMR restraints with paramagnetic compounds: Background and practical aspects
Expanding the utility of NMR restraints with paramagnetic compounds: Background and practical aspects
Publication year: 2011
Source: Progress in Nuclear Magnetic Resonance Spectroscopy, In Press, Accepted Manuscript, Available online 27 May 2011</br>
Julia, Koehler , Jens, Meiler</br>
*Highlights:*? introduction of a lanthanide ion into a protein leads to paramagnetic effects and partial alignment. ? Paramagnetic Relaxation Enhancements (PREs), Residual Dipolar Couplings (RDCs), and Pseudo-Contact Shifts (PCSs), among others, can be measured. ? amplitude of paramagnetic effects...
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05-28-2011 10:54 PM
[NMR paper] Low 13C-background for NMR-based studies of ligand binding using 13C-depleted glucose
Low 13C-background for NMR-based studies of ligand binding using 13C-depleted glucose as carbon source for microbial growth: 13C-labeled glucose and 13C-forskolin binding to the galactose-H+ symport protein GalP in Escherichia coli.
Related Articles Low 13C-background for NMR-based studies of ligand binding using 13C-depleted glucose as carbon source for microbial growth: 13C-labeled glucose and 13C-forskolin binding to the galactose-H+ symport protein GalP in Escherichia coli.
J Am Chem Soc. 2004 Jan 14;126(1):86-7
Authors: Patching SG, Herbert RB,...
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11-24-2010 09:25 PM
[U. of Ottawa NMR Facility Blog] Hahn Echo for 11B Background Suppression in Solids
Hahn Echo for 11B Background Suppression in Solids
Solids NMR probes often contain boron rich parts near the coil in which the sample resides. Boron nitride, in particular, is a material very commonly used. This can be very problematic if one wishes to collect 11B NMR data, in that a strong background signal may be observed. Even though these parts are not directly inside the coil with the sample, they do experience a small amount of rf from the coil and the coil does detect a 11B NMR signal from them. One simple way to avoid this problem is to use a Hahn echo to observe the 11B spectrum....
Background Suppression in Liquids
The bottom traces show the 11B [1H] NMR spectra for a dilute sample of NaBH4 and a "real" synthetic sample on the left and right, respectively. One can see an enormous background signal from both the NMR probe and the NMR tube. In the case of the "real" synthetic sample, the information from the spectrum is difficult or impossible to recover. The top traces show similar spectra acquired using the composite pulse. The only background signal remaining is that from the portion of the NMR tube inside the coil. This pulse sequence (without proton decoupling) is in the Bruker pulse program library called "zgbs". It is not exclusive to 11B.
Linear Mode
