scholarly journals Dynamical Models of Chemical Exchange in Nuclear Magnetic Resonance Spectroscopy

2021 ◽  
Author(s):  
Nicolas Daffern ◽  
Christopher Nordyke ◽  
Meiling Zhang ◽  
Arthur G. Palmer ◽  
John E. Straub
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Chemical Exchange ◽  
Random Phase ◽  
Rate Theory ◽  
Resonance Spectroscopy ◽  
Line Broadening ◽  
Barrier Crossing ◽  
Nuclear Magnetic

ABSTRACT Chemical exchange line broadening is an important phenomenon in nuclear magnetic resonance (NMR) spectroscopy, in which a nuclear spin experiences more than one magnetic environment as a result of chemical or conformational changes of a molecule. The dynamic process of chemical exchange strongly affects the sensitivity and resolution of NMR experiments and increasingly provides a powerful probe of the interconversion between chemical and conformational states of proteins, nucleic acids, and other biologic macromolecules. A simple and often used theoretic description of chemical exchange in NMR spectroscopy is based on an idealized 2-state jump model (the random phase or telegraph signal). However, chemical exchange can also be represented as a barrier crossing event that can be modeled by using chemical reaction rate theory. The timescale of crossing is determined by the barrier height, the temperature, and the dissipation modeled as collisional or frictional damping. This tutorial explores the connection between the NMR theory of chemical exchange line broadening and strong collision models for chemical kinetics in statistical mechanics. Theoretic modeling and numeric simulation are used to map the rate of barrier crossing dynamics of a particle on a potential energy surface to the chemical exchange relaxation rate constant. By developing explicit models for the exchange dynamics, the tutorial aims to elucidate the underlying dynamical processes that give rise to the rich phenomenology of chemical exchange observed in NMR spectroscopy. Software for generating and analyzing the numeric simulations is provided in the form of Python and Fortran source codes.

scholarly journals Recent Advances in Solid-State Nuclear Magnetic Resonance Spectroscopy

2018 ◽  
Vol 11 (1) ◽  
pp. 485-508 ◽  
Author(s):  
Sharon E. Ashbrook ◽  
John M. Griffin ◽  
Karen E. Johnston
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Solid State Nmr ◽  
Spectral Lines ◽  
Atomic Scale ◽  
Resonance Spectroscopy ◽  
Diverse Range ◽  
Nuclear Magnetic

The sensitivity of nuclear magnetic resonance (NMR) spectroscopy to the local atomic-scale environment offers great potential for the characterization of a diverse range of solid materials. Despite offering more information than its solution-state counterpart, solid-state NMR has not yet achieved a similar level of recognition, owing to the anisotropic interactions that broaden the spectral lines and hinder the extraction of structural information. Here, we describe the methods available to improve the resolution of solid-state NMR spectra and the continuing research in this area. We also highlight areas of exciting new and future development, including recent interest in combining experiment with theoretical calculations, the rise of a range of polarization transfer techniques that provide significant sensitivity enhancements, and the progress of in situ measurements. We demonstrate the detailed information available when studying dynamic and disordered solids and discuss the future applications of solid-state NMR spectroscopy across the chemical sciences.

scholarly journals Composition dependent transport diffusion in non-ideal mixtures from spatially resolved nuclear magnetic resonance spectroscopy

2018 ◽  
Vol 20 (44) ◽  
pp. 28185-28192 ◽  
Author(s):  
Christian F. Pantoja ◽  
Y. Mauricio Muñoz-Muñoz ◽  
Lorraine Guastar ◽  
Jadran Vrabec ◽  
Julien Wist
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Diffusion Coefficient ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Spatially Resolved ◽  
Transport Diffusion ◽  
Dependent Transport ◽  
Nuclear Magnetic

Nuclear magnetic resonance (NMR) spectroscopy can also be used for the measurement of the Fick diffusion coefficient.

Use of high-resolution proton nuclear magnetic resonance spectroscopy for rapid multi-component analysis of urine.

1984 ◽  
Vol 30 (3) ◽  
pp. 426-432 ◽  
Author(s):  
J R Bales ◽  
D P Higham ◽  
I Howe ◽  
J K Nicholson ◽  
P J Sadler
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
High Resolution ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Simple Method ◽  
Nuclear Magnetic

Abstract Numerous low-Mr metabolites--including creatinine, citrate, hippurate, glucose, ketone bodies, and various amino acids--have been identified in 400- and 500-MHz proton nuclear magnetic resonance (1H NMR) spectra of intact human urine. The presence of many of these was related to the specific condition of the donors: humans in different physiological states (resting, fasting, or post-exercise) and pathological conditions (e.g., diabetes mellitus, cadmium-induced renal dysfunction). We have also monitored the metabolism of simple nonendogenous compounds (methanol and ethanol) and of acetaminophen. The pH-dependencies of the NMR chemical shifts of some urine components are reported. Our studies show that high-resolution 1H NMR spectroscopy provides a fast, simple method for "fingerprint" identification of urinary compounds. In some cases, analytes can be quantified by standard additions or by comparing integrated peak areas for the metabolites with those for creatinine. Determinations of creatinine by 1H NMR spectroscopy compared well with those by an independent chemical assay based on the Jaffé reaction.

scholarly journals Nuclear Magnetic Resonance Spectroscopy for Medical and Dental Applications: A Comprehensive Review

2019 ◽  
Vol 13 (01) ◽  
pp. 124-128 ◽  
Author(s):  
Komal Zia ◽  
Talal Siddiqui ◽  
Saqib Ali ◽  
Imran Farooq ◽  
Muhammad Sohail Zafar ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Analytical Techniques ◽  
Resonance Spectroscopy ◽  
Advantages And Disadvantages ◽  
The Past ◽  
Dental Applications ◽  
Insight Into ◽  
Nuclear Magnetic

AbstractNuclear magnetic resonance (NMR) spectroscopy is one of the most significant analytical techniques that has been developed in the past few decades. A broad range of biological and nonbiological applications ranging from an individual cell to organs and tissues has been investigated through NMR. Various aspects of this technique are still under research, and many functions of the NMR are still pending a better understanding and acknowledgment. Therefore, this review is aimed at providing a general overview of the main principles, types of this technique, and the advantages and disadvantages of NMR spectroscopy. In addition, an insight into the current uses of NMR in the field of medicine and dentistry and ongoing developments of NMR spectroscopy for future applications has been discussed.

scholarly journals A Fast Self-Learning Subspace Reconstruction Method for Non-Uniformly Sampled Nuclear Magnetic Resonance Spectroscopy

2020 ◽  
Vol 10 (11) ◽  
pp. 3939 ◽  
Author(s):  
Zhangren Tu ◽  
Huiting Liu ◽  
Jiaying Zhan ◽  
Di Guo
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
The Self ◽  
Resonance Spectroscopy ◽  
Reconstruction Method ◽  
Subspace Method ◽  
High Quality ◽  
Self Learning ◽  
Nuclear Magnetic

Multidimensional nuclear magnetic resonance (NMR) spectroscopy is one of the most crucial detection tools for molecular structure analysis and has been widely used in biomedicine and chemistry. However, the development of NMR spectroscopy is hampered by long data collection time. Non-uniform sampling empowers rapid signal acquisition by collecting a small subset of data. Since the sampling rate is lower than that of the Nyquist sampling ratio, undersampling artifacts arise in reconstructed spectra. To obtain a high-quality spectrum, it is necessary to apply reasonable prior constraints in spectrum reconstruction models. The self-learning subspace method has been shown to possess superior advantages than that of the state-of-the-art low-rank Hankel matrix method when adopting high acceleration in data sampling. However, the self-learning subspace method is time-consuming due to the singular value decomposition in iterations. In this paper, we propose a fast self-learning subspace method to enable fast and high-quality reconstructions. Aided by parallel computing, the experiment results show that the proposed method can reconstruct high-fidelity spectra but spend less than 10% of the time required by the non-parallel self-learning subspace method.

Ascorbic acid, a vitamin, is observed by in vivo13C nuclear magnetic resonance spectroscopy of rat liver

1998 ◽  
Vol 274 (1) ◽  
pp. E65-E71 ◽  
Author(s):  
Ekkehard Küstermann ◽  
Joachim Seelig ◽  
Basil Künnecke
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Ascorbic Acid ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Rat Liver ◽  
Whole Body ◽  
Resonance Spectroscopy ◽  
C Nmr ◽  
Nuclear Magnetic

The first in vivo detection of a vitamin with nuclear magnetic resonance (NMR) is reported for mammalian liver. Vitamin C, also known as ascorbic acid, was monitored noninvasively in rat liver by “whole body”13C NMR spectroscopy at high field after infusion of [1,2-13C2]glucose into anesthetized rats. Generally, the carbon resonances of ascorbic acid overlap with those of other highly abundant cellular metabolites, thus precluding their observation in situ. This problem was resolved by taking advantage of the13C-13C spin couplings introduced by the two covalently bound13C nuclei in [1,2-13C2]glucose. During glucose metabolism, [5,6-13C2]ascorbic acid was synthesized, which also exhibited characteristic13C homonuclear spin couplings. This feature enabled the spectral discrimination of ascorbic acid from overlapping singlet resonances of other metabolites. Quantitative analysis of the spin-coupling patterns provided an estimate of the turnover rate of hepatic ascorbic acid in vivo (1.9 ± 0.4 nmol ⋅ min−1 ⋅ g−1) and a novel approach toward a better understanding of optimal ascorbic acid requirements in humans. The results obtained in vivo were confirmed with high-resolution proton and13C NMR spectroscopy of liver extracts.

Uses of Nuclear Magnetic Resonance Spectroscopy Technique in Pharmaceutical Analysis: A Review

2017 ◽  
Vol 8 (02) ◽  
Author(s):  
Imad Hadi Zohra ◽  
Abeer Fauzi Al-Rubaye ◽  
Mohanad Jawad Kadhim
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Ratio Method ◽  
Resonance Spectroscopy ◽  
Spectroscopic Techniques ◽  
Nuclear Magnetic

Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a magnetic field absorb and re-emit electromagnetic radiation. Many scientific techniques exploit NMR phenomena to study molecular physics, crystals, and non-crystalline materials through nuclear magnetic resonance spectroscopy. NMR phenomena are also utilized in low-field NMR, NMR spectroscopy and MRI in the Earth's magnetic field (referred to as Earth's field NMR), and in several types of magnetometers. Modern NMR spectroscopy has been emphasizing the application in biomolecular systems and plays an important role in structural biology. NMR spectroscopy is very important to identify a drug or an excipient, evaluate the level of impurities (and to elucidate the structure), observe the course of a decomposition, to evaluate residual solvents, determine the isomeric composition, i.e. the ratio of diastereomers and the enantiomeric excess by means of chiral additive, assess a single drug or drug composition, characterize a polymer mostly being a mixture and used as excipients, identify counter ions (if of organic origin and having protons), characterize an entire formulation, e.g. a tablet. Fundamentals of quantitative NMR spectroscopy NMR spectroscopy can be considered as a primary ratio method of measurement being characterized by the fact that the ratio of substances can be determined directly from the physical context of the measurement without referencing to another substance. NMR has become one of the most powerful and versatile spectroscopic techniques for the analysis of biomacromolecules, allowing characterization of biomacromolecules and their complexes up to 100 kDa. Together with X-ray crystallography.

Serum analysis by1H Nuclear Magnetic Resonance spectroscopy: a new tool for distinguishing neuromyelitis optica from multiple sclerosis

2013 ◽  
Vol 20 (5) ◽  
pp. 558-565 ◽  
Author(s):  
F-M Moussallieh ◽  
K Elbayed ◽  
JB Chanson ◽  
G Rudolf ◽  
M Piotto ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Neuromyelitis Optica ◽  
Demyelinating Diseases ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
H Nmr ◽  
Nuclear Magnetic

Background:Neuromyelitis optica (NMO) and multiple sclerosis (MS), two inflammatory demyelinating diseases, are characterized by different therapeutic strategies. Currently, the only biological diagnostic tool available to distinguish NMO from MS is the specific serum autoantibody that targets aquaporin 4, but its sensitivity is low.Objective:To assess the diagnostic accuracy of metabolomic biomarker profiles in these two neurological conditions, compared to control patients.Methods:We acquired serum spectra (47 MS, 44 NMO and 42 controls) using proton nuclear magnetic resonance (1H-NMR) spectroscopy. We used multivariate pattern recognition analysis to identify disease-specific metabolic profiles.Results:The1H-NMR spectroscopic analysis evidenced two metabolites, originating probably from astrocytes, scyllo-inositol and acetate, as promising serum biomarkers of MS and NMO, respectively. In 87.8% of MS patients, scyllo-inositol increased 0.15 to 3-fold, compared to controls and in 74.3% of NMO patients, acetate increased 0.4 to 7-fold, compared to controls. Using these two metabolites simultaneously, we can discriminate MS versus NMO patients (sensitivity, 94.3%; specificity, 90.2%).Conclusion:This study demonstrates the potential of1H-NMR spectroscopy of serum as a novel, promising analytical tool to discriminate populations of patients affected by NMO or MS.

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