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Showing results for: heating

Non-conductive and miniature fiber-optic imaging system for real-time detection of neuronal activity in time-varying electromagnetic fields.

Research RF Safe Research Library Jan 1, 2017

This paper describes a non-conductive, miniature fiber-optic imaging system designed to record neuronal activity in real time during repetitive, long-term time-varying EMF exposure. Using the system, the authors report that short exposures (

MICROWAVE RADIATION INDUCED SYNTHESIS OF HYDROXYPROPYL METHYLCELLULOSE-GRAFT- (POLYVINYLALCOHAL-CO-ACRYLIC ACID) POLYMERIC NETWORK AND ITS IN VITRO EVALUATION.

Research RF Safe Research Library Jan 1, 2017

This in vitro materials study compares microwave irradiation versus conventional water-bath heating for synthesizing HPMC-graft-(PVA-co-acrylic acid) hydrogels loaded with captopril. The authors report that microwave-synthesized hydrogels had more uniformly porous structures and higher swelling ratios, with…

Gold Nanocluster-Mediated Cellular Death under Electromagnetic Radiation.

Research RF Safe Research Library Jan 1, 2017

This study investigated 2 nm protein-stabilized gold nanoclusters in six mammalian cell types under 1 GHz electromagnetic field exposure. The authors report low intrinsic toxicity of the nanoclusters, but a significant decrease in cell viability when nanocluster-incubated cells were exposed to the 1 GHz field,…

Efficient DNA ligation by selective heating of DNA ligase with a radio frequency alternating magnetic field.

Research RF Safe Research Library Jan 1, 2016

This in vitro study describes a method to improve DNA ligation by immobilizing T4 DNA ligase on ferromagnetic particles and applying a radio frequency alternating magnetic field. The field causes the particles to dissipate heat, which the authors report selectively heats and activates the ligase while minimally…

Radio frequency induced heating of an insulated wire during magnetic resonance imaging.

Research RF Safe Research Library Jan 1, 2016

This engineering study investigated RF-induced power deposition near straight insulated leads in an MRI context under different incident electric field profiles. Using 3-D electromagnetic simulations, the authors compared simulation-derived power deposition with implant model predictions. For the setups examined,…

Effects of Anatomical Differences on Electromagnetic Fields, SAR, and Temperature Change.

Research RF Safe Research Library Jan 1, 2016

This engineering study evaluates how anatomical/geometric differences affect MRI RF safety metrics. Simulations and a bovine-phantom experiment found that similar transmit B-field patterns can coincide with notably different peak SAR and temperature rise. The authors highlight challenges in using…

Magnetic Nanoparticles with High Specific Absorption Rate at Low Alternating Magnetic Field.

Research RF Safe Research Library Jan 1, 2015

This paper describes synthesis and characterization of magnetic nanoparticles intended for tumor hyperthermia applications. It reports that the particles show relatively high specific absorption rate (22–200 W/g) under a 160 kHz alternating magnetic field at 100–500 Oe, despite low saturation magnetization. The…

Effect of marination in gravy on the radio frequency and microwave processing properties of beef.

Research RF Safe Research Library Jan 1, 2015

This engineering/food science study measured dielectric constant (ε'), dielectric loss factor (ε″), and power penetration depth in beef and gravy preparations across 27–1,800 MHz and 20–130 °C. The dielectric properties generally decreased with increasing frequency, and penetration depth decreased with increasing…

Biodegradable shape memory nanocomposites with thermal and magnetic field responsiveness.

Research RF Safe Research Library Jan 1, 2013

This engineering study reports fabrication of a biodegradable PLLA shape-memory nanocomposite incorporating surface-modified Fe3O4 nanoparticles. The composite showed improved tensile/mechanical and shape-memory properties compared with PLLA, and shape recovery could be triggered by an alternating magnetic field.…

Citrate-capped gold nanoparticle electrophoretic heat production in response to a time-varying radiofrequency electric-field.

Research RF Safe Research Library Jan 1, 2012

This in vitro study examines RF-induced heat production in citrate-capped gold nanoparticle suspensions while minimizing confounding Joule heating from ionic buffers. It reports size-dependent heating detectable only for ≤10 nm particles, with heating scaling with concentration and surface area and being attenuated…

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.…

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…

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…

The influence of temperature and electric field history on the conductivity of the charge density wave system o-TaS3.

Research RF Safe Research Library Jan 1, 2010

This laboratory study examined how temperature and prior electric-field exposure affect low-field conductivity in the charge density wave material o-TaS3. Conductivity differed between cooling and heating below the CDW transition, and applying increasing electric fields drove the system toward a stable,…

Influence of mashed potato dielectric properties and circulating water electric conductivity on radio frequency heating at 27 MHz.

Research RF Safe Research Library Jan 1, 2008

This engineering study used experiments, computer simulations, and simplified analytical calculations to examine how mashed potato dielectric properties and circulating water electrical conductivity affect RF heating at 27 MHz. The authors report that higher circulating water conductivity and higher salt content in…

Improvement in magnetic field immunity of externally-coupled transcutaneous energy transmission system for a totally implantable artificial heart.

Research RF Safe Research Library Jan 1, 2008

This engineering study addresses interference between induction-heating cookers and an externally coupled transcutaneous energy transmission system for a totally implantable artificial heart. The authors report that magnetic flux from an IH cooker can couple into the TET transformer and affect system performance. A…

Coil design considerations for deep-brain transcranial magnetic stimulation (dTMS).

Research RF Safe Research Library Jan 1, 2008

This engineering-focused conference paper proposes figures of merit to evaluate deep-brain transcranial magnetic stimulation (dTMS) coil designs, focusing on depth penetration, scalp stimulation, focality, and energy. It analyzes circular crown and C-core coils and reports reduced electric-field attenuation with…

Combined effect of temperature and pulsed electric fields on apple juice peroxidase and polyphenoloxidase inactivation.

Research RF Safe Research Library Jan 1, 2008

This laboratory study evaluated pulsed electric fields (PEF) combined with preheating to inactivate peroxidase (POD) and polyphenoloxidase (PPO) in freshly prepared apple juice. The highest reported inactivation occurred with preheating to 50°C and PEF at 40 kV/cm for 100 μs, exceeding the reductions seen with…

Alkali (NaOH) pretreatment of switchgrass by radio frequency-based dielectric heating.

Research RF Safe Research Library Jan 1, 2008

This engineering study reports using radio-frequency (RF)-based dielectric heating to assist NaOH pretreatment of switchgrass to improve enzymatic digestibility. Under the stated conditions, RF-assisted pretreatment produced higher xylose and glucose yields than conventional heating and maintained higher yields at…

In-line application of electric field in capillary separation systems: Joule heating, pH and conductivity.

Research RF Safe Research Library Jan 1, 2008

This engineering study investigated factors affecting current when an electric field is applied in-line in a capillary separation system. Temperature measurements and a replicated cooling setup were used to estimate Joule heating effects, which were reported to be relatively small. In contrast, significant pH shifts…

Dependence of RF heating on SAR and implant position in a 1.5T MR system.

Research RF Safe Research Library Jan 1, 2007

This phantom study measured RF-induced heating of a stainless steel humerus implant during 1.5T MR imaging while varying SAR, implant angle to B0, and implant position in the RF coil. Temperature rise at implant tips increased linearly with SAR, with larger rises when the implant was parallel to B0. Heating decreased…

Physics and biology of mobile telephony

Research RF Safe Research Library Jan 1, 2000

This review argues that current mobile-telephony safety guidelines address excessive microwave heating but may not account for potential non-thermal influences of low-intensity, pulsed radiation. It highlights an asserted oscillatory similarity between pulsed microwave signals and certain electrochemical activities…

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