scholarly journals A study of J-coupling spectroscopy using the Earth’s field nuclear magnetic resonance inside a laboratory

2010 ◽  
Vol 81 (10) ◽  
pp. 104104 ◽  
Author(s):  
Shu-Hsien Liao ◽  
Ming-Jye Chen ◽  
Hong-Chang Yang ◽  
Shin-Yi Lee ◽  
Hsin-Hsien Chen ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
J Coupling ◽  
Nuclear Magnetic

Conformational dynamics detected by nuclear magnetic resonance NOE values and J coupling constants

1988 ◽  
Vol 110 (11) ◽  
pp. 3393-3396 ◽  
Author(s):  
Horst. Kessler ◽  
Christian. Griesinger ◽  
Joerg. Lautz ◽  
Arndt. Mueller ◽  
Wilfred F. Van Gunsteren ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Conformational Dynamics ◽  
Coupling Constants ◽  
J Coupling ◽  
J Coupling Constants ◽  
Nuclear Magnetic

scholarly journals A first principles theory of nuclear magnetic resonance J-coupling in solid-state systems

2007 ◽  
Vol 127 (20) ◽  
pp. 204107 ◽  
Author(s):  
Siân A. Joyce ◽  
Jonathan R. Yates ◽  
Chris J. Pickard ◽  
Francesco Mauri
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Solid State ◽  
Magnetic Resonance ◽  
First Principles ◽  
J Coupling ◽  
Nuclear Magnetic

Nuclear magnetic resonance J coupling constant polarizabilities of hydrogen peroxide: A basis set and correlation study

2012 ◽  
Vol 33 (23) ◽  
pp. 1845-1853 ◽  
Author(s):  
Hanna Kjaer ◽  
Monia R. Nielsen ◽  
Gabriel I. Pagola ◽  
Marta B. Ferraro ◽  
Paolo Lazzeretti ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Correlation Study ◽  
Basis Set ◽  
Coupling Constant ◽  
J Coupling ◽  
Nuclear Magnetic

scholarly journals Sensor Configuration and Algorithms for Power-Line Interference Suppression in Low Field Nuclear Magnetic Resonance

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3566 ◽  
Author(s):  
Xiaolei Huang ◽  
Hui Dong ◽  
Quan Tao ◽  
Mengmeng Yu ◽  
Yongqiang Li ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Power Line ◽  
Computational Time ◽  
Frequency Noise ◽  
Low Field ◽  
J Coupling ◽  
Sensor Configuration ◽  
Lf Nmr ◽  
Nuclear Magnetic

Low field (LF) nuclear magnetic resonance (NMR) shows potential advantages to study pure heteronuclear J-coupling and observe the fine structure of matter. Power-line harmonics interferences and fixed-frequency noise peaks might introduce discrete noise peaks into the LF-NMR spectrum in an open environment or in a conductively shielded room, which might disturb J-coupling spectra of matter recorded at LF. In this paper, we describe a multi-channel sensor configuration of superconducting quantum interference devices, and measure the multiple peaks of the 2,2,2-trifluoroethanol J-coupling spectrum. For the case of low signal to noise ratio (SNR) < 1, we suggest two noise suppression algorithms using discrete wavelet analysis (DWA), combined with either least squares method (LSM) or gradient descent (GD). The de-noising methods are based on spatial correlation of the interferences among the superconducting sensors, and are experimentally demonstrated. The DWA-LSM algorithm shows a significant effect in the noise reduction and recovers SNR > 1 for most of the signal peaks. The DWA-GD algorithm improves the SNR further, but takes more computational time. Depending on whether the accuracy or the speed of the de-noising process is more important in LF-NMR applications, the choice of algorithm should be made.

The solution conformations of amino acids from molecular dynamics simulations of Gly-X-Gly peptides: comparison with NMR parameters

1998 ◽  
Vol 76 (2-3) ◽  
pp. 164-170 ◽  
Author(s):  
David van der Spoel
Keyword(s):  
Molecular Dynamics ◽  
Amino Acids ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Random Coil ◽  
J Coupling ◽  
Dynamics Simulations ◽  
Nuclear Magnetic

The conformations that amino acids can adopt in the random coil state are of fundamental interest in the context of protein folding research and studies of protein–peptide interactions. To date, no detailed quantitative data from experimental studies have been reported; only nuclear magnetic resonance parameters such as chemical shifts and J coupling constants have been reported. These experimental nuclear magnetic resonance data represent averages over multiple conformations, and hence they do not provide unique structural information. I have performed relatively long (2.5 ns) molecular dynamics simulations of Gly-X-Gly tripeptides, surrounded by explicit water molecules, where X represents eight different amino acids with long side chains. From the trajectories one can calculate time averaged backbone chemical shifts and 3JNHα coupling constants and compare these with experimental data. These calculated quantities are quite close to the experimental values for most amino acids, suggesting that these simulations are a good model for the random coil state of the tripeptides. On the basis of my simulations I predict 3Jαβ coupling constants and present dihedral distributions for the Φ, Ψ, as well as χ1 and χ2 angles. Finally, I present correlation plots for these dihedral angles.Key words: molecular dynamics (MD), nuclear magnetic resonance (NMR) spectroscopy, J-coupling, chemical shift, dihedral probability distribution.

13C-Decoupled J-Coupling Spectroscopy Using Two-Dimensional Nuclear Magnetic Resonance at Zero-Field

2017 ◽  
Vol 8 (7) ◽  
pp. 1512-1516 ◽  
Author(s):  
Tobias F. Sjolander ◽  
Michael C. D. Tayler ◽  
Arne Kentner ◽  
Dmitry Budker ◽  
Alexander Pines
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Zero Field ◽  
Two Dimensional ◽  
J Coupling ◽  
Nuclear Magnetic

J-Coupling Nuclear Magnetic Resonance Spectroscopy of Liquids in nT Fields

2006 ◽  
Vol 128 (3) ◽  
pp. 714-715 ◽  
Author(s):  
Johannes Bernarding ◽  
Gerd Buntkowsky ◽  
Sven Macholl ◽  
Stefan Hartwig ◽  
Martin Burghoff ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
J Coupling ◽  
Nuclear Magnetic

An emerging technology: Nuclear magnetic resonance microscopy

1988 ◽  
Vol 46 ◽  
pp. 1000-1001
Author(s):  
M.J. Hennessy ◽  
E. Kwok
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Basic Research ◽  
Local Environment ◽  
Magnetic Resonance Images ◽  
Nmr Microscopy ◽  
Mri Scans ◽  
Temperature Relaxation ◽  
Nuclear Magnetic

Much progress in nuclear magnetic resonance microscope has been made in the last few years as a result of improved instrumentation and techniques being made available through basic research in magnetic resonance imaging (MRI) technologies for medicine. Nuclear magnetic resonance (NMR) was first observed in the hydrogen nucleus in water by Bloch, Purcell and Pound over 40 years ago. Today, in medicine, virtually all commercial MRI scans are made of water bound in tissue. This is also true for NMR microscopy, which has focussed mainly on biological applications. The reason water is the favored molecule for NMR is because water is,the most abundant molecule in biology. It is also the most NMR sensitive having the largest nuclear magnetic moment and having reasonable room temperature relaxation times (from 10 ms to 3 sec). The contrast seen in magnetic resonance images is due mostly to distribution of water relaxation times in sample which are extremely sensitive to the local environment.

Nuclear magnetic resonance microscopy

1989 ◽  
Vol 47 ◽  
pp. 828-829
Author(s):  
Paul C. Lauterbur
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Fields ◽  
Signal To Noise ◽  
Field Gradients ◽  
Useful Signal ◽  
Magnetic Field Gradients ◽  
Observation Times ◽  
Nuclear Magnetic

Nuclear magnetic resonance imaging can reach microscopic resolution, as was noted many years ago, but the first serious attempt to explore the limits of the possibilities was made by Hedges. Resolution is ultimately limited under most circumstances by the signal-to-noise ratio, which is greater for small radio receiver coils, high magnetic fields and long observation times. The strongest signals in biological applications are obtained from water protons; for the usual magnetic fields used in NMR experiments (2-14 tesla), receiver coils of one to several millimeters in diameter, and observation times of a number of minutes, the volume resolution will be limited to a few hundred or thousand cubic micrometers. The proportions of voxels may be freely chosen within wide limits by varying the details of the imaging procedure. For isotropic resolution, therefore, objects of the order of (10μm) may be distinguished.Because the spatial coordinates are encoded by magnetic field gradients, the NMR resonance frequency differences, which determine the potential spatial resolution, may be made very large. As noted above, however, the corresponding volumes may become too small to give useful signal-to-noise ratios. In the presence of magnetic field gradients there will also be a loss of signal strength and resolution because molecular diffusion causes the coherence of the NMR signal to decay more rapidly than it otherwise would. This phenomenon is especially important in microscopic imaging.

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