Development Of Nuclear Magnetic Resonance Research Articles

Nuclear magnetic resonance imaging of simulated voids in cement slurries

This paper reports on the initial technological development of nuclear magnetic resonance (NMR) imaging which was motivated primarily by applications in medicine and biology: however, increasing attention is now being given to applications to nonliving systems such as porous media and polymer science. These applications place higher demands on hardware performance and ingenuity in imaging protocol design, principally because of the broader linewidths and shorter relaxation times found a such heterogeneous systems compared with those of biological tissues. NMR relaxometry in heterogeneous systems has provided insight into pore sizes, surface area, and molecular dynamics in porous media, suspensions and hydrating cement. Most of the latter are studies of the [sup 1]H (proton) resonance of water in a hydrating slurry. The motivation of this study was to develop a technique to which movement of gas voids within a slurry could be examined experimentally. Natural gas migration is an important failure mode of oil-well cementing operations. The imaging speeds achieved (down to 5 seconds per slice-selective image) indicate that the technique is feasible for such applications. Other viable applications may be in imaging aggregate distribution or crack detection in model concretes and in ceramic casting, or indeed in void detection in anymore » other proton-containing material with comparable values of its NMR parameters.« less

Some applications of NMR to the study of magnetically-ordered materials with emphasis on the short-range order in (Fe-B)-based crystalline and amorphous alloys

In this review, we summatize recent developments in nuclear magnetic resonance (NMR) studies on (Fe-B)-based crystalline and amorphous alloys, focusing on the application of NMR in identifying the existence of short-range order (SRO), determining the types of SRO, characterizing the behavior of the SRO and exploring the effect of the SRO on the magnetic properties for the Fe-B system. NMR experiments reveal that certain local environments surrounding the B atoms exist in both crystalline and amorphous Fe-B alloys. The type of SRO existing in this rapidly quenched system can be either o-Fe 3B or bct-Fe 3B, or a mixture, depending on the composition and processing factors, especially the carbon content and quenching speed. The SRO originates from a strong covalent bonding between the B and Fe atoms. As this interaction plays the same role in both crystalline and amorphous Fe-B alloys, the SRO which occurs in the amorphous Fe-B alloys is similar to the SRO which exists in their crystalline counterparts. NMR, in combination with magnetization measurements, provides evidence indicating that the SRO existing in the amorphous Fe-B alloys has a significant effect on their soft magnetic properties and that different types of SRO may act differently, thus providing an opportunity to improve the magnetic properties by changing the SRO. In connection with reviewing the achievements of NMR studies in recent years, brief comments concerning the advantages and potential of NMR experiments in the investigation of other magnetically-ordered materials will also be presented.

ChemInform Abstract: Some Developments in Nuclear Magnetic Resonance of Solids

Nuclear magnetic resonance (NMR) spectroscopy continues to evolve as a primary technique in the study of solids. This review briefly describes some developments in modern NMR that demonstrate its exciting potential as an analytical tool in fields as diverse as physics, chemistry, biology, geology, and materials science. Topics covered include motional narrowing by sample reorientation, multiple-quantum and overtone spectroscopy, probing porous solids with guest atoms and molecules, two-dimensional NMR studies of chemical exchange and spin diffusion, experiments at extreme temperatures, NMR imaging of solid materials, and low-frequency and zero-field magnetic resonance. These developments permit increasingly complex structural and dynamical behavior to be probed at a molecular level and thus add to our understanding of macroscopic properties of materials.

Erratum: Some Developments in Nuclear Magnetic Resonance in Solids

In the article by B.F. Chmelka and A. Pines, "Some developments in nuclear magnetic resonance in solids" (6 Oct., p. 71), several references were transposed. Figure 1 was adapted from ( 6 ) [C.A. Fyfe et al., J. Am. Chem. Soc. 110, 3373 (1988)], not( 10 ) and ( 14 ), as printed. Figure 2 was adapted from ( 7 ) [H.B. Cole, S.W. Sparks, D.A. Torchia, in preparation], not ( 11 ) ,as printed. The reference, to rotational resonance (p. 74, col. 2, line 22) should have been ( 10 ) [D.P. Raleigh et al., J. Am. Chem. Soc. , in press], not (7), as printed. The authors in reference ( 55 ) should have been D.R. Nelson and F. Spaepen.

Erratum: Some Developments in Nuclear Magnetic Resonance in Solids

Erratum: Some Developments in Nuclear Magnetic Resonance in Solids

Magnetic resonance spectroscopy of tumors and potential in vivo clinical applications: A review : Cancer Res 1989; 49:770–779

The development of nuclear magnetic resonance (NMR) spectroscopy as an established research tool for noninvasive studies of cancer cells and for in vivo studies of tumors in animals and humans has led to the possibility that this technique may be used in the future for clinical research studies and monitoring of therapy in cancer patients in combination with magnetic resonance imaging. This article provides a brief qualitative explanation of NMR spectroscopy and then reviews the cell and animal studies detailing which biochemicals can be observed in vivo by 31P, 13C, and 1H NMR. The human studies done to date and their potential for diagnosis and monitoring of therapy are then discussed. In addition, 19F NMR spectroscopic studies of fluorinated drugs and 1H and 31P NMR studies relating to drug resistance are mentioned. The current technical limitations and developing improvements are indicated also.

Some Developments in Nuclear Magnetic Resonance of Solids

Nuclear magnetic resonance (NMR) spectroscopy continues to evolve as a primary technique in the study of solids. This review briefly describes some developments in modern NMR that demonstrate its exciting potential as an analytical tool in fields as diverse as physics, chemistry, biology, geology, and materials science. Topics covered include motional narrowing by sample reorientation, multiple-quantum and overtone spectroscopy, probing porous solids with guest atoms and molecules, two-dimensional NMR studies of chemical exchange and spin diffusion, experiments at extreme temperatures, NMR imaging of solid materials, and low-frequency and zero-field magnetic resonance. These developments permit increasingly complex structural and dynamical behavior to be probed at a molecular level and thus add to our understanding of macroscopic properties of materials.

ChemInform Abstract: Recent Developments in NMR Spectroscopy of Organometallic Compounds

Publisher Summary This chapter discusses the recent developments in nuclear magnetic resonance (NMR) spectroscopy of organometallic compounds. The experimental aspects and some results from multinuclear NMR spectroscopy and some examples from solid-state NMR spectroscopy are examined. Modern NMR spectrometers have powerful routines to modify the free induction decay and hence the resolution and signal/noise ratio. Homonuclear decoupling has long been established as a valuable tool in determining which nuclei are coupled. The Nuclear Overhauser Enhancement (NOE) is one of the most valuable tools in determining the connectivity among protons and, to a lesser extent, between protons and other nuclei. The sensitivity of an NMR experiment depends on the population difference among the energy levels. The Incredible Natural Abundurice Double Quantum Transfer Experiment (in adequate) pulse sequence was originally designed to detect 13 C – 13 C coupling without the confusion of the 13 C singlets due to the species without adjacent 13 C atoms. The normal π /2 pulse excites nuclei over a wide range of frequencies. Broadband decoupling has been applied for many years to obtain X-nuclei NMR spectra without 1 H coupling. Until very recently, variable-temperature solid-state NMR spectroscopy with magic angle spinning has been restricted close to room temperature because of the great difficulty of spinning the sample at high speed.

Design and construction of "SUMRIS"--the Sydney University magnetic resonance imaging system.

A magnetic resonance imaging system for investigation and development of nuclear magnetic resonance (NMR) imaging techniques is being constructed by the NMR, Imaging Group within the School of Electrical Engineering at the University of Sydney. The system will also be capable of spatially-localized in-vivo spectroscopy. Primary requirements of a research instrument are flexibility and low cost, precluding purchase of a commercial system and necessitating in-house construction. The appropriate design strategy adopted was to start by building a simple NMR apparatus and expand it in steps, progressing towards a complete imaging and spectroscopy system.

The spatial mapping of translational diffusion coefficients by the NMR imaging technique

With the recent development of nuclear magnetic resonance (NMR) imaging it is important to characterise and understand the NMR response of tissues. There are several reasons why such characterisation of tissues using NMR parameters would be useful. It may provide a helpful diagnostic guide and could lead to a deeper understanding of the underlying processes responsible for many pathological and physiological states of tissues. For several years, hydrogen density, spin-lattice relaxation and spin-spin relaxation maps of objects have been obtained using the NMR imaging technique. The authors have developed a method for the spatial mapping of an additional NMR parameter, the molecular translational diffusion coefficient D. In addition the technique will permit the measurement of perfusion and blood flow rates.

Nuclear magnetic resonance (NMR) proton imaging in cancer

INTRODUCTION WITHIN 10 yr of the introduction of X-ray computed tomography (X-ray CT), diagnostic radiology has found itself on the threshold of a second revolution in imaging technique. The development of nuclear magnetic resonance (NMR) for imaging now enables the diagnostician to not only see normal anatomy and gross pathological change, but to study organ function and pathophysiologic change in vivo. A great deal of interest in the technique has been generated, because of its ability to produce high-resolution images of areas which hitherto have been difficult to image, such as the posterior fossa, brain stem and neck (Fig. 2), because of its ability to demonstrate blood vessels without the use of contrast agents (Fig. 3) and because tumours show very clearly, again without the use of contrast (Fig. 4). However, much basic clinical research into its true place in diagnosis has yet to be performed. This paper attempts to describe in simple terms the NMR phenomenon and how it is applied for imaging. It also describes some of the work which has been performed at the Aberdeen Royal Infirmary over the past 4 yr to find its place in cancer diagnosis and management.

New developments in nuclear magnetic resonance (NMR) imaging

The basic principles of NMRI are explained. Examples are given of the current medical uses of imaging with protons and other nuclei as well. Further developments towards spectroscopic imaging are discussed.

Electronics and Instrumentation for NMR Imaging

The development of Nuclear Magnetic Resonance (NMR) imaging has brought together the experimental techniques of NMR spectroscopy and image processing with the consequence that new experimental requirements and apparatus are currently being developed. Examples of these requirements include the large amounts of data which can be generated and the effect on data processing and storage requirements. Also, the increased size of objects under investigation necessitate some major changes in the magnet and r.f. system. A discussion of these specific requirements is presented together with an overview of all components of the NMR imaging system.