The Time Average Magnetic Field at the Nucleus in Nuclear Magnetic Resonance Experiments

Dickinson, W.C.

doi:10.1103/physrev.81.717

Cited by 263 publications

(96 citation statements)

References 30 publications

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“…(However, it was often possible to check this calibration over various points in the time course and it was very stable over time, typically within +0.05 ppm.) It was necessary to determine the chemical shift of the reference in each experiment because of the geometry-dependent susceptibility shift of the paramagnetic external reference solution (24) and the inability to position it with extreme reproducibility from mouse to mouse.…”

Section: Methodsmentioning

confidence: 99%

In vivo metabolic effects of hyperglycemia in murine radiation-induced fibrosarcoma: a 31P NMR investigation.

Evelhoch¹,

Sapareto²,

Jick³

et al. 1984

Proc. Natl. Acad. Sci. U.S.A.

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The hyperglycemia-induced in vivo metabolic changes pro4uced in subcutaneous murine RIF-1 tumors, grown on female C3H/Anf mice, were examined with 31P surface-coil NMR. Serum glucose levels were elevated 4-fold by bolus intrape& toneal injection of 0. Hyperglycemia, an increase in the serum glucose concentration ([Glc]b), has been reported to selectively enhance the thermal sensitivity of tumors and thereby represents a useful adjuvant of hyperthermia in the treatment of cancer ;1-5).The side effects associated with short-term hyperglycemia are minor (for nondiabetic subjects), the prominent effect being an increase in thirst, which can be relieved by increased intake of water (6). Although hyperglycemia alone had no effect on the growth rate in any of the tumors examined (5), hyperglycemia increased the thermal sensitivity of all rat and murine tumors examined (2, 4, 5, 10).Since the introduction of surface-coil NMR for studies of in vivo tissue (13) MATERIALS AND METHODSA radiation-induced fibrosarcoma, RIF-1, obtained from R. F. Kallman (Stanford University), was maintained by the serial in vitro-in vivo passage technique described by Twentyman et al. (17). Solid tumors were produced by subcutaneous injection of 105 cells in 0.1 ml of media into the shaved right flanks of female C3H/Anf mice. The in vivo tumors grow to a suitable size (1.0-1.5 cm in diameter) in about 14-21 days. Tumor volume was estimated by calculating the volume of an ellipsoid from the equation V = (r/6)a2b, in which a and b represent major and minor axes dimensions.Mice were anesthetized with 0.5% (vol/vol) halothane

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Section: Methodsmentioning

confidence: 99%

In vivo metabolic effects of hyperglycemia in murine radiation-induced fibrosarcoma: a 31P NMR investigation.

Evelhoch¹,

Sapareto²,

Jick³

et al. 1984

Proc. Natl. Acad. Sci. U.S.A.

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“…The basic requirement for a valid measurement is that the resonance frequencies for sample and reference be obtained under precisely the same value of the magnetic induction, B 0 . In some experimental measurements, as described below, B 0 (sample) ≠ B 0 (reference) as a result of bulk (isotropic) magnetic susceptibility (BMS) effects, which give rise to demagnetizing fields [5]. In these circumstances, it is essential to apply a suitable correction, as described in Section 5, and it is appropriate to designate a "corrected" or "true" chemical shift to distinguish it from the "apparent" or observed value obtained by rote application of eq.…”

Section: General Aspects Of Chemical Shiftsmentioning

confidence: 99%

Further conventions for NMR shielding and chemical shifts (IUPAC Recommendations 2008)

Harris

Becker

Menezes

et al. 2008

Pure and Applied Chemistry

574

479

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IUPAC has published a number of recommendations regarding the reporting of nuclear magnetic resonance (NMR) data, especially chemical shifts. The most recent publication [Pure Appl. Chem.73, 1795 (2001)] recommended that tetramethylsilane (TMS) serve as a universal reference for reporting the shifts of all nuclides, but it deferred recommendations for several aspects of this subject. This document first examines the extent to which the 1H shielding in TMS itself is subject to change by variation in temperature, concentration, and solvent. On the basis of recently published results, it has been established that the shielding of TMS in solution [along with that of sodium-3-(trimethylsilyl)propanesulfonate, DSS, often used as a reference for aqueous solutions] varies only slightly with temperature but is subject to solvent perturbations of a few tenths of a parts per million (ppm). Recommendations are given for reporting chemical shifts under most routine experimental conditions and for quantifying effects of temperature and solvent variation, including the use of magnetic susceptibility corrections and of magic-angle spinning (MAS). This document provides the first IUPAC recommendations for referencing and reporting chemical shifts in solids, based on high-resolution MAS studies. Procedures are given for relating 13C NMR chemical shifts in solids to the scales used for high-resolution studies in the liquid phase. The notation and terminology used for describing chemical shift and shielding tensors in solids is reviewed in some detail, and recommendations are given for best practice.

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“…It was introduced in electrostatics by Lorentz (10) but applies equally well to magnetostatic situations (e.g., 11). It was first used in the context of NMR by Dickinson (12). The sphere of Lorentz is a notional sphere drawn around a nucleus; it is large enough for all the molecules external to it to be treated as a macroscopic continuum that is locally uniform.…”

Section: Analytic Strategymentioning

confidence: 99%

Magnetic susceptibility: Further insights into macroscopic and microscopic fields and the sphere of Lorentz

Durrant

Hertzberg

Kuchel

2003

Concepts Magnetic Resonance

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To make certain quantitative interpretations of spectra from NMR experiments carried out on heterogeneous samples, such as cells and tissues, we must be able to estimate the magnetic and electric fields experienced by the resonant nuclei of atoms in the sample. Here, we analyze the relationships between these fields and the fields obtained by solving the Maxwell equations that describe the bulk properties of the materials present. This analysis separates the contribution to these fields of the molecule in which the atom in question is bonded, the "host" fields, from the contribution of all the other molecules in the system, the "external" fields. We discuss the circumstances under which the latter can be found by determining the macroscopic fields in the sample and then removing the averaged contribution of the host molecule. We demonstrate that the results produced by the, so-called, "sphere of Lorentz" construction are of general validity in both static and time-varying cases. This analytic construct, however, is not "mystical" and its justification rests not on any sphericity in the system but on the local uniformity and isotropy, i.e., spherical symmetry, of the medium when averaged over random microscopic configurations. This local averaging is precisely that which defines the equations that describe the macroscopic fields. Hence, the external microscopic fields, i n a suitably averaged sense, can be estimated from the macroscopic fields. We then discuss the calculation of the external fields and that of the resonant nucleus in NMR experiments.

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The Time Average Magnetic Field at the Nucleus in Nuclear Magnetic Resonance Experiments

Cited by 263 publications

References 30 publications

In vivo metabolic effects of hyperglycemia in murine radiation-induced fibrosarcoma: a 31P NMR investigation.

In vivo metabolic effects of hyperglycemia in murine radiation-induced fibrosarcoma: a 31P NMR investigation.

Further conventions for NMR shielding and chemical shifts (IUPAC Recommendations 2008)

Magnetic susceptibility: Further insights into macroscopic and microscopic fields and the sphere of Lorentz

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