Improvements in technical assessment and protocol for EPR evaluation of magnetic fields effects on a radical pair reaction

Gualtieri, G. J.; Colacicchi, S.; Carnicelli, Veronica; Giulio, Antonio Di

doi:10.1016/j.bpc.2004.11.014

Cited by 3 publications

(13 citation statements)

References 12 publications

(18 reference statements)

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“…As expected at these frequencies, it is the modulation of the 14 N nuclear hyperfine anisotropy that provides the dominant relaxation pathway, with the g-anisotropy modulation somewhat less, and spin-rotation almost negligible. The contributions from the thermally-activated processes, and from modulation of the 14 N hyperfine interaction, increase as the frequency is reduced. 23 Simulations of EPR spectra from phospholipid-based probes, labelled at the C4 to C14 positions of the an-2 chain, in liquid-ordered membranes of dimyristoylphosphatidylcholine, containing 40 mol% cholesterol, measured at 94 and 9 GHz frequencies, have been presented.…”

Section: Technical and Theoreticalsupporting

confidence: 63%

“…Various approaches to the analysis of the ESR spectra of these systems are compared and contrasted. The effects 14 of either static or pulsed magnetic fields on the rate of the reaction between Fremy's salt and ascorbic acid have been investigated, and are accountable within the radical pair mechanism. Since the effects are small, they were enhanced using a field gradient technique, which is reported to detect both the reacting radicals and the radical intermediates involved in the reaction.…”

Section: Technical and Theoreticalmentioning

confidence: 99%

“…Tumbling correlation times were calculated from the CW X-band spectra. The dependence of T 1e on the tumbling correlation time of the probe was modelled from the modulation of the 14 N hyperfine and g-anisotropy, spin-rotational coupling, and from one or more thermally-activated processes. As expected at these frequencies, it is the modulation of the 14 N nuclear hyperfine anisotropy that provides the dominant relaxation pathway, with the g-anisotropy modulation somewhat less, and spin-rotation almost negligible.…”

Section: Technical and Theoreticalmentioning

confidence: 99%

“…The dependence of T 1e on the tumbling correlation time of the probe was modelled from the modulation of the 14 N hyperfine and g-anisotropy, spin-rotational coupling, and from one or more thermally-activated processes. As expected at these frequencies, it is the modulation of the 14 N nuclear hyperfine anisotropy that provides the dominant relaxation pathway, with the g-anisotropy modulation somewhat less, and spin-rotation almost negligible. The contributions from the thermally-activated processes, and from modulation of the 14 N hyperfine interaction, increase as the frequency is reduced.…”

Section: Technical and Theoreticalmentioning

confidence: 99%

See 3 more Smart Citations

Electron spin resonance (some chemical applications)

Rhodes¹

2006

Annu. Rep. Prog. Chem., Sect. C: Phys. Chem.

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Section: Technical and Theoreticalsupporting

confidence: 63%

Section: Technical and Theoreticalmentioning

confidence: 99%

Section: Technical and Theoreticalmentioning

confidence: 99%

Section: Technical and Theoreticalmentioning

confidence: 99%

See 2 more Smart Citations

Electron spin resonance (some chemical applications)

Rhodes¹

2006

Annu. Rep. Prog. Chem., Sect. C: Phys. Chem.

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“…In addition, electron paramagnetic resonance (EPR) or electron spin resonance (ESR) spectroscopy is an extremely powerful tool for direct detection and quantification of free radicals (171)(172). An introduction to EPR/ESR spectroscopy has been well documented.…”

Section: Perspectivesmentioning

confidence: 99%

Effects of static magnetic fields in biology: role of free radicals

Okano¹

2008

Front Biosci

112

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Biological systems can respond to a wide range of static magnetic fields (SMF). Some of these responses seem to be mediated partly through free radical reactions. For example, in magnetic sense and navigation using the geomagnetic field, one of the most promising mechanisms for explaining magnetic compass is "a radical pair mechanism". Biological free radicals are most commonly oxygen or nitrogen based with an unpaired electron, leading to the terms "reactive oxygen species (ROS)" or "reactive nitrogen species (RNS)". When applying SMF to medical treatment, coupling SMF exposure with possible chemotherapy of cancers is a novel fascinating area that SMF could enhance agent-induced ROS production against tumors. In addition, one of the potent mechanisms of SMF effects on hemodynamics and blood pressure has sometimes been linked to nitric oxide pathway. However, health and environmental concerns have been raised because the SMF effects on oxidative stress leading to genetic mutation and apoptosis/necrosis have been found. It seems to take place from free radical generation.

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Static Magnetic Field Effect on the Fremy’s Salt−Ascorbic Acid Chemical Reaction Studied by Continuous-Wave Electron Paramagnetic Resonance

et al. 2009

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Static magnetic field effect in the framework of the radial pair mechanism (RPM) theory was studied on the biologically significant chemical reaction between ascorbic acid and Fremy's salt. The data indicate that the reaction rate depends on the applied magnetic field strength. The time scale of the studied reaction and the improved continuous-wave electron paramagnetic resonance system allowed for the first time the direct comparison of the amplitude differences between exposed and control samples in the strictly same boundary conditions. Until now the RPM was studied in a different time scale, focusing only on faster reactions by time-resolved techniques or by spectrophotometer measurement. The magnetic field effects presently measured can not be extended tout court to living systems; however the understanding of magnetic field sensitivity in basic chemical reaction in vitro could help clarifying the underlying basic step of interaction between magnetic fields and biological systems.

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Improvements in technical assessment and protocol for EPR evaluation of magnetic fields effects on a radical pair reaction

Cited by 3 publications

References 12 publications

Electron spin resonance (some chemical applications)

Electron spin resonance (some chemical applications)

Effects of static magnetic fields in biology: role of free radicals

Static Magnetic Field Effect on the Fremy’s Salt−Ascorbic Acid Chemical Reaction Studied by Continuous-Wave Electron Paramagnetic Resonance

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