Increased blood oxygen level-dependent (BOLD) sensitivity in the mouse somatosensory cortex during electrical forepaw stimulation using a cryogenic radiofrequency probe.
Research
RF Safe Research Library
Jan 1, 2011
This engineering-focused mouse fMRI study evaluated a 400-MHz cryogenic RF probe (CryoProbe) versus a conventional room-temperature surface coil during electrical forepaw stimulation. The CryoProbe increased image SNR and temporal SNR and reduced temporal noise compared with the room-temperature coil. The authors…
Reduction of implant RF heating through modification of transmit coil electric field.
Research
RF Safe Research Library
Jan 1, 2011
This engineering study describes modifying MRI RF transmit coil electric-field distributions to create electric field-free zones without substantially changing transmit sensitivity. Phantom experiments are reported to show reduced implant heating when a zero electric-field plane is aligned with the implant location.…
Transient and steady-state magnetic fields induce increased fluorodeoxyglucose uptake in the rat hindbrain.
Research
RF Safe Research Library
Jan 1, 2011
This animal PET study examined whether a weak 60-Hz magnetic field alters brain glucose utilization in rats. The abstract reports increased FDG uptake in hindbrain voxels when a 2.5-G field was oriented orthogonally to the sagittal plane, but not when field direction varied randomly. Distinct activation effects were…
Human keratinocytes in culture exhibit no response when exposed to short duration, low amplitude, high frequency (900 MHz) electromagnetic fields in a reverberation chamber.
Research
RF Safe Research Library
Jan 1, 2011
This in vitro study exposed normal human epidermal keratinocytes to non-thermal 900 MHz electromagnetic fields in a mode-stirred reverberation chamber under two short-duration conditions. Microarray analysis found only limited gene modulation (20 genes) with small expression ratios and no shared genes across…
Correction of main and transmit magnetic field (B0 and B1) inhomogeneity effects in multicomponent-driven equilibrium single-pulse observation of T1 and T2.
Research
RF Safe Research Library
Jan 1, 2011
This methods paper addresses how B0 (main field) and B1 (transmit field) inhomogeneities can bias SPGR and bSSFP steady-state MRI signals used for multicomponent T1/T2 relaxometry and myelin water analysis. It describes using DESPOT1-HIFI to calibrate flip angles and adding a B0-related parameter with multiple…
Effect of external normal and parallel electric fields on 180° ferroelectric domain walls in PbTiO₃.
Research
RF Safe Research Library
Jan 1, 2011
This modeling study applies uniform electric fields parallel and normal to 180° ferroelectric domain walls in PbTiO3 and computes equilibrium structures using anharmonic lattice statics. The authors report that electric fields can substantially increase domain wall thickness and identify a critical field Ec above…
Evaluation of magnetic resonance safety of veterinary radiofrequency identification devices at 1 T.
Research
RF Safe Research Library
Jan 1, 2011
This study evaluated MRI safety parameters for three commercial veterinary RFID microchips at 1 T, assessing movement forces, heating, artifacts, and device function. Translation and torque were reported to be larger than expected from normal activity, but no significant heating was observed and microchip function…
A rapid and facile synthesis of nanofibrillar polyaniline using microwave radiation.
Research
RF Safe Research Library
Jan 1, 2010
This engineering study describes a microwave-assisted method to synthesize polyaniline (PANI) nanofibers. Reported yields under microwave irradiation were similar to conventional synthesis but achieved in minutes rather than hours. Structural and morphological characterization (FTIR, Raman, SEM, TEM) reportedly…
Orientation and Dynamics of ZnO Nanorod Liquid Crystals in Electric Fields.
Research
RF Safe Research Library
Jan 1, 2010
This materials study reports that ZnO nanorod polymer hybrids can form liquid-crystalline phases and exhibit orientation switching under an applied AC electric field. The orientation reportedly changes from planar to homeotropic, analogous to switching in low-molecular liquid crystals. Dielectric measurements and…
Ohmic heating of peaches in the wide range of frequencies (50 Hz to 1 MHz).
Research
RF Safe Research Library
Jan 1, 2010
This engineering/food science study examined ohmic heating of peaches at 60 V/cm using bipolar pulses across frequencies from 50 Hz to 1 MHz. Heating time to a target temperature and multiple electrical properties were frequency-dependent, particularly for intact tissue. The authors report faster electro-thermal…
Disintegration efficiency of pulsed electric field induced effects on onion (Allium cepa L.) tissues as a function of pulse protocol and determination of cell integrity by ¹H-NMR relaxometry.
Research
RF Safe Research Library
Jan 1, 2010
This experimental study examined how pulsed electric field (PEF) processing parameters affect cell membrane rupture in onion tissue disks, using ion leakage as the primary integrity measure. Disintegration efficiency increased with field strength up to 500 V/cm and varied with pulse width, pulse number, and…
High-intensity pulsed electric fields processing parameters affecting polyphenoloxidase activity of strawberry juice.
Research
RF Safe Research Library
Jan 1, 2010
This study evaluated high-intensity pulsed electric fields (HIPEF) as a processing method to inactivate polyphenoloxidase (PPO) in strawberry juice. Using response surface methodology at a constant electric field of 35 kV/cm, the authors report strong PPO reductions across tested parameter ranges. Bipolar mode,…
Electrooptical effects in colloid systems subjected to short pulses of strong electric field.
Research
RF Safe Research Library
Jan 1, 2010
This study describes an electrooptical technique for polydisperse colloid solutions using short pulses of strong sine-shaped electric field, intended for systems that cannot withstand prolonged field exposure. The authors report that key particle parameters can still be extracted from the resulting experimental data.…
Spin current pumped by a rotating magnetic field in zigzag graphene nanoribbons.
Research
RF Safe Research Library
Jan 1, 2010
This theoretical study models electron spin resonance and spin/charge pumping in zigzag graphene nanoribbons driven by a transverse rotating magnetic field without applied bias. It reports that pumped spin current density increases with ribbon size and rotating-field intensity, and that even-chain ribbons can also…
High magnetic field induced charge density waves and sign reversal of the Hall coefficient in graphite.
Research
RF Safe Research Library
Jan 1, 2010
This condensed-matter study investigates highly oriented pyrolytic graphite under very strong magnetic fields at low temperature. It reports a magnetic-field-induced charge density wave transition and a subsequent sign reversal of the Hall coefficient from negative to positive. The reported angular dependence…
Interaction quench dynamics in the Kondo model in the presence of a local magnetic field.
Research
RF Safe Research Library
Jan 1, 2010
This theoretical study analyzes quench dynamics in the Kondo model on the Toulouse line in the presence of a local magnetic field. The authors report exact analytical results for local spin dynamics, finding that relaxation timescales are set by the Kondo scale. They also describe damped transient oscillations in…
Effects of magnetic field and pressure on the intermediate valence state of YbPd.
Research
RF Safe Research Library
Jan 1, 2010
This condensed-matter physics study examined how high magnetic fields and pressure affect magnetization, transport, and thermodynamic properties of the intermediate-valence compound YbPd. The authors report that the Yb valence state and two first-order transitions are stable up to 55 T, while increasing pressure…
The effect of magnetic field and disorders on the electronic transport in graphene nanoribbons.
Research
RF Safe Research Library
Jan 1, 2010
This paper presents a mesoscopic transport modeling framework (NEGF plus a real-space π-orbital model) to study how a uniform perpendicular magnetic field affects electronic transport in armchair graphene nanoribbons. The authors report width-dependent equilibrium current profiles and edge-localized transport under…
Electronic properties of a graphene antidot in magnetic fields.
Research
RF Safe Research Library
Jan 1, 2010
This paper describes unusual electronic properties of a graphene antidot created by a piecewise constant potential in a magnetic field. It reports near-complete localization of electron probability within the barrier region under some conditions and a symmetry linking antidot and dot states with identical…
Magnetodeformation effects and the swelling of ferrogels in a uniform magnetic field.
Research
RF Safe Research Library
Jan 1, 2010
This laboratory/materials study examined deformation and swelling of magnetic field sensitive polymer gels (ferrogels) in a static, uniform magnetic field. The authors report that gels with randomly distributed magnetic particles exhibited weak magnetodeformation, whereas gels with aligned particles showed no…
Electron dynamics in inhomogeneous magnetic fields.
Research
RF Safe Research Library
Jan 1, 2010
This paper is a review of two-dimensional electron dynamics in microscopically inhomogeneous magnetic fields, focusing on magnetic potentials varying on scales smaller than the mean free path. It covers early work on localization in random magnetic fields, methods to fabricate magnetic potentials, and drift-diffusion…
Quantitative determination of domain distribution in SrTiO3-competing effects of applied electric field and mechanical stress.
Research
RF Safe Research Library
Jan 1, 2010
This neutron diffraction study quantifies how tetragonal structural domains in SrTiO3 redistribute below 105 K under external electric fields and uniaxial mechanical stress. The authors report that electric field and stress act competitively, and that applying both produces complex domain redistribution. The results…
Thermodynamic behavior of the XXZ Heisenberg s = 1/2 chain around the factorizing magnetic field.
Research
RF Safe Research Library
Jan 1, 2010
This paper theoretically investigates zero- and finite-temperature behavior of an anisotropic antiferromagnetic Heisenberg XXZ spin-1/2 chain under a transverse magnetic field, focusing between the factorizing and critical fields. It reports an entanglement phase transition at the factorizing field where entanglement…
Electric field gradients in (111)In-doped (Hf/Zr)3Al2 and (Hf/Zr)4Al3 mixed compounds: ab initio calculations, perturbed angular correlation measurements and site preference.
Research
RF Safe Research Library
Jan 1, 2010
This materials-physics study investigated quadrupolar hyperfine interactions of (111)In→(111)Cd probes in polycrystalline Zr4Al3 and Hf4Al3 containing minority (Zr/Hf)3Al2 phases. The authors observed a strong preference of (111)In solutes for the minority (Zr/Hf)3Al2 phases. Ab initio EFG calculations were used to…
Effect of two length scales on the properties of MgB(2) for arbitrary applied magnetic field.
Research
RF Safe Research Library
Jan 1, 2010
This paper analyzes anomalous magnetic-field and temperature dependences observed in MgB(2) superconductivity experiments using a two-order-parameter Ginzburg-Landau theory with two length scales. The authors numerically solve the nonlinear Ginzburg-Landau equations for arbitrary applied fields between Hc1 and Hc2 to…