Measurement of electric fields induced in a human subject due to natural movements in static magnetic fields or exposure to alternating magnetic field gradients

2007 ◽  
Vol 53 (2) ◽  
pp. 361-373 ◽  
Author(s):  
P M Glover ◽  
R Bowtell
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Fields ◽  
Human Subject ◽  
Alternating Magnetic Field ◽  
Static Magnetic Fields ◽  
Field Gradients ◽  
Magnetic Field Gradients

Nuclear magnetic resonance microscopy

1989 ◽  
Vol 47 ◽  
pp. 828-829
Author(s):  
Paul C. Lauterbur
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Fields ◽  
Signal To Noise ◽  
Field Gradients ◽  
Useful Signal ◽  
Magnetic Field Gradients ◽  
Observation Times ◽  
Nuclear Magnetic

Nuclear magnetic resonance imaging can reach microscopic resolution, as was noted many years ago, but the first serious attempt to explore the limits of the possibilities was made by Hedges. Resolution is ultimately limited under most circumstances by the signal-to-noise ratio, which is greater for small radio receiver coils, high magnetic fields and long observation times. The strongest signals in biological applications are obtained from water protons; for the usual magnetic fields used in NMR experiments (2-14 tesla), receiver coils of one to several millimeters in diameter, and observation times of a number of minutes, the volume resolution will be limited to a few hundred or thousand cubic micrometers. The proportions of voxels may be freely chosen within wide limits by varying the details of the imaging procedure. For isotropic resolution, therefore, objects of the order of (10μm) may be distinguished.Because the spatial coordinates are encoded by magnetic field gradients, the NMR resonance frequency differences, which determine the potential spatial resolution, may be made very large. As noted above, however, the corresponding volumes may become too small to give useful signal-to-noise ratios. In the presence of magnetic field gradients there will also be a loss of signal strength and resolution because molecular diffusion causes the coherence of the NMR signal to decay more rapidly than it otherwise would. This phenomenon is especially important in microscopic imaging.

Sensing of Local, Highly Concentrated Magnetic Field Gradients in Magnetotactic Bacteria Induces Motility Reversal

2012 ◽  
Author(s):  
Lina M. González ◽  
Warren C. Ruder ◽  
William C. Messner ◽  
Philip R. LeDuc
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetotactic Bacteria ◽  
Chemical Gradients ◽  
Field Gradients ◽  
Magnetic Field Gradients ◽  
Direction Of Movement ◽  
Unicellular Organisms ◽  
Sense And Respond ◽  
Direction Reversal

Many motile unicellular organisms have evolved specialized behaviors for detecting and responding to chemical gradients (chemotaxis) or oxygen (aerotaxis), while magnetotactic bacteria sense magnetic fields to align their direction of movement. Herein we show that Magnetospirillum magneticum (AMB-1) have the ability to sense and respond not only to the direction of magnetic fields of naturally occurring magnitude, but also to local, highly concentrated magnetic field gradients that do not occur in their natural environment. We imposed these gradients through our system integrating Helmholtz coils and permalloy (Ni80Fe20) microstructures. The AMB-1 exhibit three distinct behaviors as they approached gradients near the microstructures—unidirectional, single direction reversal, and double direction reversal. These results indicate previously unknown capabilities of the magnetic sensing systems of AMB-1.

scholarly journals Magnetomigration of rare-earth ions in inhomogeneous magnetic fields

2016 ◽  
Vol 18 (39) ◽  
pp. 27342-27350 ◽  
Author(s):  
Agnieszka Franczak ◽  
Koen Binnemans ◽  
Jan Fransaer Jan Fransaer
Keyword(s):  
Magnetic Field ◽  
Rare Earth ◽  
Magnetic Fields ◽  
Opposite Direction ◽  
Rare Earth Ions ◽  
Field Gradients ◽  
Magnetic Field Gradients ◽  
Paramagnetic Ions

In magnetic field gradients, paramagnetic ions are pulled to the regions of the strongest magnetic fields while the diamagnetic ions move in the opposite direction.

Magnetically Actuable Scaffolds for Tissue Regeneration

2008 ◽  
Author(s):  
Julia J. Mack ◽  
Abigail A. Corrin ◽  
Sergio L. dos Santos e Lucato ◽  
Brian N. Cox ◽  
Jennifer S. Andrew ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Tissue Engineering ◽  
Magnetic Fields ◽  
Tissue Regeneration ◽  
Three Dimensional ◽  
Functionalized Polymers ◽  
Polymer Scaffolds ◽  
Biocompatible Polymer ◽  
Field Gradients ◽  
Magnetic Field Gradients

Presented here are methods to fabricate magnetically modified biocompatible polymer scaffolds, which can be actuated by remotely applied magnetic fields. The magnitude of the actuation is shown to be biologically useful by simple tests in known magnetic fields and magnetic field gradients. Methods of processing the functionalized polymers into three-dimensional scaffolds have been demonstrated, suggesting wide applicability in tissue engineering.

Magnetic separation: its application in mining, waste purification, medicine, biochemistry and chemistry

2017 ◽  
Vol 46 (19) ◽  
pp. 5925-5934 ◽  
Author(s):  
M. Iranmanesh ◽  
J. Hulliger
Keyword(s):  
Magnetic Field ◽  
Solid State ◽  
Magnetic Fields ◽  
Medical Research ◽  
Permanent Magnets ◽  
Solid State Chemistry ◽  
High Magnetic Fields ◽  
Field Gradients ◽  
Superconducting Coils ◽  
Magnetic Field Gradients

The use of strong magnetic field gradients and high magnetic fields generated by permanent magnets or superconducting coils has found applications in many fields such as mining, solid state chemistry, biochemistry and medical research.

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