Precision High Speed Current Regulators for Occasionally Switched Inductive Loads

Redfield, Alfred G.; Fite, Warner; Bleich, Hermann E.

doi:10.1063/1.1683481

Cited by 105 publications

(33 citation statements)

References 9 publications

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“…The field-cycling relaxometer used for these measurements has been described elsewhere (26,27). It measures 1 / T I NMRD profiles of solvent protons over the magnetic field range 2.5 X lop4 to 1.2 T (corresponding to about 0.01 to 50 MHz proton Larmor frequency), rapidly, under computer control, and with an uncertainty of the fit to a single exponential of less than k 1 % under the present conditions.…”

Section: Nmrd Measurementsmentioning

confidence: 99%

Nuclear magnetic relaxation dispersion profiles of aqueous solutions of a series of gd(nota) analogs

Geraldes

Brown²,

Brücher³

et al. 1992

Magnetic Resonance in Med

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Nuclear magnetic relaxation dispersion (NMRD) profiles and ESR linewidths have been measured for a series of neutral Gd(3+)-triazamacrocyclic complexes and compared with previous data for the simplest member of the macrocyclic triaza series, Gd(NOTA), and for the widely studied linear triaza complex, Gd(DTPA)2-. Water proton relaxivities and their temperature dependence were found to vary widely with the size of the triaza macrocycle and the identity of the side-chain chelating groups. The number of rapidly exchanging water molecules directly coordinated to the Gd3+ ion (q) was found to vary from 2 to 4 for eight of the ten complexes examined and a linear relationship between the 50-MHz relaxivity value and integral values of q is presented for this series of complexes. tau s values derived from ESR linewidths for some of the complexes are in reasonable agreement with those derived from their NMRD profiles; however, those complexes which either tended to form aggregates in solution or gave evidence for multiple averaged solution structures showed broad, near Lorentzian linewidths which were clearly not dominated by the electron spin relaxation time (tau s).

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Section: Nmrd Measurementsmentioning

confidence: 99%

Nuclear magnetic relaxation dispersion profiles of aqueous solutions of a series of gd(nota) analogs

Geraldes

Brown²,

Brücher³

et al. 1992

Magnetic Resonance in Med

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“…Specialized techniques for relaxation-dispersion measurements were developed in several laboratories in the late 1960s (Redfield et al 1968;Florkowski et al 1969;Kimmich & Noack 1970a), and were soon applied to the protein-hydration problem (Koenig & Schillinger 1969;Blicharska et al 1970;Kimmich & Noack 1970b). Extending over four decades in frequency, the new water 1 H MRD data represented an experimental breakthrough, but, as regards the interpretation, they raised more questions than they answered.…”

Section: Magnetic Relaxation As a Probe Of Protein Hydration Dynamicsmentioning

confidence: 99%

Protein hydration dynamics in solution: a critical survey

Halle

2004

Phil. Trans. R. Soc. Lond. B

500

576

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The properties of water in biological systems have been studied for well over a century by a wide range of physical techniques, but progress has been slow and erratic. Protein hydration-the perturbation of water structure and dynamics by the protein surface-has been a particularly rich source of controversy and confusion. Our aim here is to critically examine central concepts in the description of protein hydration, and to assess the experimental basis for the current view of protein hydration, with the focus on dynamic aspects. Recent oxygen-17 magnetic relaxation dispersion (MRD) experiments have shown that the vast majority of water molecules in the protein hydration layer suffer a mere twofold dynamic retardation compared with bulk water. The high mobility of hydration water ensures that all thermally activated processes at the protein-water interface, such as binding, recognition and catalysis, can proceed at high rates. The MRD-derived picture of a highly mobile hydration layer is consistent with recent molecular dynamics simulations, but is incompatible with results deduced from intermolecular nuclear Overhauser effect spectroscopy, dielectric relaxation and fluorescence spectroscopy. It is also inconsistent with the common view of hydration effects on protein hydrodynamics. Here, we show how these discrepancies can be resolved.

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“…FFC instruments based on home-built spectrometers and suitable for water NMRD studies of protein solutions have been developed in several laboratories (Redfield et al, 1968;Florkowski et al, 1969;Kimmich and Noack, 1970b;Conti, 1986;Koenig and Brown, 1987;Job et al, 1996), and a commercial FFC spectrometer is available since 1995 (Sykora and Ferrante, 1995). The low-inductance air core magnets used for FFC are generally optimized for short switching times and minimal power consumption rather than for high field homogeneity (Schweikert et al, 1988).…”

Section: The Ffc Spectrometermentioning

confidence: 99%