Ultra-high field NMR spectroscopy: observation of proton-proton dipolar coupling in paramagnetic bis[tolyltris(pyrazolyl)borato]cobalt(II)

1981 ◽  
Vol 103 (18) ◽  
pp. 5602-5603 ◽  
Author(s):  
Aksel A. Bothner-By ◽  
Peter J. Domaille ◽  
C. Gayathri
Keyword(s):  
Nmr Spectroscopy ◽  
High Field ◽  
Dipolar Coupling ◽  
Ultra High Field ◽  
Proton Proton ◽  
Spectroscopy Observation

scholarly journals Heterogeneous Polymer Dynamics Explored Using Static 1H NMR Spectra

2020 ◽  
Vol 21 (15) ◽  
pp. 5176
Author(s):  
Todd M. Alam ◽  
Joshua P. Allers ◽  
Brad H. Jones
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
Dipolar Coupling ◽  
Polymer Materials ◽  
Dynamic Heterogeneity ◽  
Proton Proton ◽  
Dynamic Correlation ◽  
Thermosetting Polymers ◽  
Heterogeneous Polymer ◽  
The Impact

NMR spectroscopy continues to provide important molecular level details of dynamics in different polymer materials, ranging from rubbers to highly crosslinked composites. It has been argued that thermoset polymers containing dynamic and chemical heterogeneities can be fully cured at temperatures well below the final glass transition temperature (Tg). In this paper, we described the use of static solid-state 1H NMR spectroscopy to measure the activation of different chain dynamics as a function of temperature. Near Tg, increasing polymer segmental chain fluctuations lead to dynamic averaging of the local homonuclear proton-proton (1H-1H) dipolar couplings, as reflected in the reduction of the NMR line shape second moment (M2) when motions are faster than the magnitude of the dipolar coupling. In general, for polymer systems, distributions in the dynamic correlation times are commonly expected. To help identify the limitations and pitfalls of M2 analyses, the impact of activation energy or, equivalently, correlation time distributions, on the analysis of 1H NMR M2 temperature variations is explored. It is shown by using normalized reference curves that the distributions in dynamic activation energies can be measured from the M2 temperature behavior. An example of the M2 analysis for a series of thermosetting polymers with systematically varied dynamic heterogeneity is presented and discussed.

HTS insert coils for ultra high field NMR spectroscopy

1997 ◽  
Vol 7 (2) ◽  
pp. 885-888 ◽  
Author(s):  
D.W. Hazelton ◽  
M.T. Gardner ◽  
J.M. Weloth ◽  
J.A. Rice ◽  
L.R. Motowidlo ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
High Field ◽  
Ultra High Field

scholarly journals Ultra-high-field 7-T MRI in multiple sclerosis and other demyelinating diseases: from pathology to clinical practice

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Nicolo’ Bruschi ◽  
Giacomo Boffa ◽  
Matilde Inglese
Keyword(s):  
Multiple Sclerosis ◽  
High Field ◽  
Neurological Diseases ◽  
Lesion Detection ◽  
Demyelinating Diseases ◽  
Metabolic Imaging ◽  
Central Vein ◽  
Ultra High Field ◽  
Functional Features

Abstract Magnetic resonance imaging (MRI) is essential for the early diagnosis of multiple sclerosis (MS), for investigating the disease pathophysiology, and for discriminating MS from other neurological diseases. Ultra-high-field strength (7-T) MRI provides a new tool for studying MS and other demyelinating diseases both in research and in clinical settings. We present an overview of 7-T MRI application in MS focusing on increased sensitivity and specificity for lesion detection and characterisation in the brain and spinal cord, central vein sign identification, and leptomeningeal enhancement detection. We also discuss the role of 7-T MRI in improving our understanding of MS pathophysiology with the aid of metabolic imaging. In addition, we present 7-T MRI applications in other demyelinating diseases. 7-T MRI allows better detection of the anatomical, pathological, and functional features of MS, thus improving our understanding of MS pathology in vivo. 7-T MRI also represents a potential tool for earlier and more accurate diagnosis.

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