Nuclear magnetic resonance (NMR) micro-imaging of stems of Linum usitatissimum

1992 ◽  
Vol 119 (2) ◽  
pp. 157-164 ◽  
Author(s):  
G. J. McDougall ◽  
B. A. Goodman ◽  
J. A. Chudek
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Linum Usitatissimum ◽  
Structural Information ◽  
Paramagnetic Species ◽  
Proton Density ◽  
Relaxation Rates ◽  
Histological Techniques ◽  
Advantages And Disadvantages ◽  
Nuclear Magnetic

SUMMARYNuclear magnetic resonance (NMR) micro-imaging techniques have been employed to study noninvasively the spatial distribution of mobile protons (1H) around the cotyledonary node of flax (Linum usitatissimum) plants of two differing growth morphologies. The gross anatomy of the tissues of the stem can be discerned as a result of differences in their mobile 1H contents. The technique produced excellent images of the complex changes in stem structure that occur at the point of origin of side shoots. Detailed structure within the xylem could be visualized and the presence of fibre bundles deduced as dark areas amongst tissues of higher 1H signal intensity.As a result of the non-invasive and non-destructive nature of NMR-imaging, the images obtained have been compared to micrographs obtained by conventional histological techniques on the same plant tissue. In general, the two approaches produce comparable results, but the NMR images are influenced by the relaxation properties of the protons as well as their concentration. Paramagnetic species, such as Mn2+ ions, produce enhanced relaxation rates of protons in their vicinity and an apparent increase in proton density at short recycle times. Thus an NMR image can yield both chemical and structural information. Some of the advantages and disadvantages of this technique over conventional histological methods are discussed.

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.

Solid State NMR Measurements for Preliminary Lifetime Assessments in λ-Irradiated and Thermally Aged Siloxane Elastomers

2004 ◽  
Vol 851 ◽  
Author(s):  
Sarah C. Chinn ◽  
Julie L. Herberg ◽  
April M. Sawvel ◽  
Robert S. Maxwell
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Solid State ◽  
Magnetic Resonance ◽  
Coupling Constants ◽  
Screening Tools ◽  
Engineering Properties ◽  
Relaxation Rates ◽  
Nmr Studies ◽  
Wide Range ◽  
Nuclear Magnetic

ABSTRACTSiloxanes have a wide variety of applications throughout the aerospace industry which take advantage of their exceptional insulating and adhesive properties and general resilience. They also offer a wide range of tailorable engineering properties with changes in composition and filler content. They are, however, subject to degradation in radiatively and thermally harsh environments. We are using solid state nuclear magnetic resonance techniques to investigate changes in network and interfacial structure in siloxane elastomers and their correlations to changes in engineering performance in a series of degraded materials. Nuclear magnetic resonance (NMR) parameters such as transverse (T2) relaxation times, cross relaxation rates, and residual dipolar coupling constants provide excellent probes of changes crosslink density and motional dynamics of the polymers caused by multi-mechanism degradation. The results of NMR studies on aged siloxanes are being used in conjunction with other mechanical tests to provide insight into component failure and degradation kinetics necessary for preliminary lifetime assessments of these materials as well as into the structure-property relationships of the polymers. NMR and magnetic resonance imaging (MRI) results obtained both from high resolution NMR spectrometers as well as low resolution benchtop NMR screening tools will be presented.

scholarly journals Verification of precision, accuracy, and characteristics of dual-energy X-ray absorptiometry and nuclear magnetic resonance in the analysis of mouse body composition

2020 ◽  
Author(s):  
Kyung-Wan Baek ◽  
Ji-Seok Kim ◽  
Jin Sung Park ◽  
So-Jeong Kim ◽  
Yong-Chan Ha ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Body Composition ◽  
Magnetic Resonance ◽  
Dual Energy ◽  
The Body ◽  
Experimental Animals ◽  
X Ray ◽  
Advantages And Disadvantages ◽  
Measurement Efficiency ◽  
Nuclear Magnetic

Abstract Background: As an instrument for measuring body composition in experimental animals, dual-energy X-ray absorptiometry (DXA) is ideal for accuracy, cost, and measurement efficiency. However, there is too little insight into the effectiveness of the various aspects of applying DXA to experimental animals. Therefore, we investigated whether to compare and verify the precision and accuracy of DXA and nuclear magnetic resonance (NMR) animal body composition analyzers. We used 30 ICR mice in the study. First, in order to evaluate the reproducibility of DXA and NMR, we did repeated measurements by repositioning each mouse in anesthesia and euthanasia states. Subsequently, the accuracy of each device was evaluated by comparing the weight measured before the experiment, the weight of the tissue extracted from the mice after the experiment, and the measured DXA and NMR. In addition, when measuring the body composition of animals, we compared the time and the measurable body composition parameters and summarized the advantages and disadvantages of the two devices.Results: Compared to NMR, DXA had the advantage of a fast measurement of bone composition and rapid image analysis. In addition, DXA showed a higher correlation (> 95%) with FM, body weight, and fBMC baseline than did NMR (> 85%).Conclusion: In conclusion, DXA was confirmed to have higher precision and measurement accuracy than did NMR. Therefore, DXA is an effective method for evaluating the body composition of experimental animals.

The Wellcome Foundation Lecture, 1984 - Nuclear magnetic resonance imaging in medicine: medical and biological applications and problems

1986 ◽  
Vol 226 (1245) ◽  
pp. 391-419 ◽  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Pulse Sequence ◽  
Clinical Work ◽  
Mental States ◽  
Response To Therapy ◽  
Whole Body ◽  
Proton Density ◽  
Transform Method ◽  
Nuclear Magnetic

From early biological work and the first T 1 nuclear magnetic resonance (n. m. r.) animal image in 1974, whole-body patient images, by using a two-dimensional Fourier transform method were achieved in Aberdeen in 1980 with a 0.04 T vertical resistive magnet. Different pulse sequences produce images dependent by different amounts on proton density, T 1 and T 2 , and for clinical work it is advantageous to use more than one pulse sequence to image pathology. The slow improvement of spatial resolution with increasing standing magnetic field strength is discussed and information on the T 1 and T 2 contrast dependence is reviewed: it suggests that the gains from high fields may be less than believed hitherto. Electrocardiogram gating can be used to produce moving images of the beating heart; blood flow can be imaged and surface radiofrequency coils are used for improved detail. N. m. r. imaging has considerable potential for studying response to therapy; mental states and dementia; tissue generation; discriminating body fat and body fluids. Other nuclei such as 23 Na can be imaged and the potential to image fluorine-labelled pharmaceuticals could be very exciting; n. m. r. contrast agents are now being developed. Images formed T 1 values measured for each pixel are very useful for diagnosis, but the numerical values themselves are less valuable for distinctive pathological identification. With 15 companies manufacturing n. m. r. imagers and over 200 in use in hospitals, the technique is rapidly becoming established in diagnostic clinical practice and some typical uses are presented.

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