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electromagnetic fields body

A Ghadimi-Moghadam, S M J Mortazavi, A Hosseini-Moghadam, M Haghani, S Taeb, M A Hosseini, N Rastegariyan, F Arian, L Sanipour, S Aghajari, S A R Mortazavi, A Soofi, M R Dizavandi
MRI workers are occupationally exposed to static and time-varying gradient magnetic fields. While the 24-hour time-averaged exposure to static magnetic fields is about a few mT, the maximum static field strength can be as high as 500 mT during patient setup. Over the past several years, our laboratory has performed extensive experiments on the health effects of exposure of animal models and humans to different sources of electromagnetic fields such as cellular phones, mobile base stations, mobile phone jammers, laptop computers, radars, dentistry cavitrons and MRI...
September 2018: Journal of Biomedical Physics & Engineering
Łukasz Januszkiewicz, Paolo Di Barba, Sławomir Hausman
The purpose of this research was to improve the performance of a wireless body area sensor network, operating on a person in the seated and standing positions. Optimization-focused on both the on-body transmission channel and off-body link performance. The system consists of three nodes. One node (on the user's head) is fixed, while the positions of the other two (one on the user's trunk and the other on one leg) with respect to the body (local coordinates) are design variables. The objective function used in the design process is characterized by two components: the first controls the wireless channel for on-body data transmission between the three sensor nodes, while the second controls the off-body transmission between the nodes and a remote transceiver...
October 11, 2018: Sensors
Chidozie H Ewurum, Yingying Guo, Seang Pagnha, Zhao Feng, Xiongbiao Luo
Orthopedic surgery is a widely performed clinical procedure that deals with problems in relation to the bones, joints, and ligaments of the human body, such as musculoskeletal trauma, spine diseases, sports injuries, degenerative diseases, infections, tumors, and congenital disorders. Surgical navigation is generally recognized as the next generation technology of orthopedic surgery. The development of orthopedic navigation systems aims to analyze pre-, intra- and/or postoperative data in multiple modalities and provide an augmented reality 3-D visualization environment to improve clinical outcomes of surgical orthopedic procedures...
2018: Advances in Experimental Medicine and Biology
Julian Moore, Sharon Castellanos, Sheng Xu, Bradford Wood, Hongliang Ren, Zion Tsz Ho Tse
Magnetic resonance within the field of wireless power transfer has seen an increase in popularity over the past decades. This rise can be attributed to the technological advances of electronics and the increased efficiency of popular battery technologies. The same principles of electromagnetic theory can be applied to the medical field. Several medical devices intended for use inside the body use batteries and electrical circuits that could be powered wirelessly. Other medical devices limit the mobility or make patients uncomfortable while in use...
October 10, 2018: Annals of Biomedical Engineering
Claudio Molinari, Ian Stoppa, Nicola Limardo, Francesca Uberti
The potentially harmful nature of electromagnetic fields (EMF) and static magnetic fields (SMF) has become a major problem in recent years. All these elements could be combined to produce cellular responses. For example, the orientation of molecules of water or other complex molecules, growth and cell viability, cell morphology, and intracellular metabolic pathways have demonstrated binding to magnetic fields. The effect of EMF and SMF on humans is a topic of great importance, especially because modern technology has introduced artificial magnetic fields such as those generated by power lines, mobile communications, and medical imaging equipment...
2018: Evidence-based Complementary and Alternative Medicine: ECAM
Seyed Asaad Karimi, Iraj Salehi, Teimor Shykhi, Samad Zare, Alireza Komaki
There are many controversies about the safety of extremely low-frequency electromagnetic field (ELF-EMF) on body health and cognitive performance. In the present study, we explored the effects of ELF-EMF on oxidative stress and behaviors of rats. Seventy-two adult male Wistar rats were randomly divided into following groups, control, sham exposure group and the ELF-EMF exposure groups (1 μT, 100 μT, 500 μT, and 2000 μT). After 60 days exposure (2 h/day), elevated plus maze (EPM), Morris water maze (MWM) and Passive avoidance learning (PAL) tasks were used to evaluate the anxiety-like behavior, spatial and passive learning and memory, respectively...
October 2, 2018: Behavioural Brain Research
Zhi-Hua Xu, Chang-Ping Du, Ming-Yao Xia
Weak electric currents are induced in moving seawater by cutting the geomagnetic fields. These electric currents can produce measurable electromagnetic fields that may be used for some purposes such as monitoring of ocean internal waves. This article is aimed at presenting the procedure to calculate the electromagnetic fields owing to the wake raised by an undersea moving slender body. A pair of Havelock point sources are introduced to model the moving body, which generate the similar wake at places far from the body...
October 2, 2018: Scientific Reports
Laleh Golestanirad, John Kirsch, Giorgio Bonmassar, Sean Downs, Behzad Elahi, Alastair Martin, Maria-Ida Iacono, Leonardo M Angelone, Boris Keil, Lawrence L Wald, Julie Pilitsis
Access to MRI is limited for patients with deep brain stimulation (DBS) implants due to safety hazards, including radiofrequency (RF) heating of tissue surrounding the leads. Computational models provide an exquisite tool to explore the multi-variate problem of RF heating and help better understand the interaction of electromagnetic fields and biological tissues. This paper presents a computational approach to assess RF-induced heating, in terms of specific absorption rate (SAR) in the tissue, around the tip of bilateral DBS leads during MRI at 64MHz/1...
September 19, 2018: NeuroImage
Benjamin Kalloch, Jens Bode, Mikhail Kozlov, André Pampel, Mario Hlawitschka, Bernhard Sehm, Arno Villringer, Harald E Möller, Pierre-Louis Bazin
PURPOSE: Simulating the interaction of the human body with electromagnetic fields is an active field of research. Individualized models are increasingly being used, as anatomical differences affect the simulation results. We introduce a processing pipeline for creating individual surface-based models of the human head and torso for application in simulation software based on unstructured grids. The pipeline is designed for easy applicability and is publicly released on figshare. METHODS: The pipeline covers image acquisition, segmentation, generation of segmentation masks, and surface mesh generation of the single, external boundary of each structure of interest...
September 19, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
James Rizkalla, Matthew Jeffers, Paul Salama, Maher Rizkalla
Background: Femoral neck fractures are common injuries managed by orthopedic surgeons across the world. From pediatrics to geriatrics, disruption of the blood supply to the femoral neck is a well-recognized source of morbidity and mortality, oftentimes resulting in avascular necrosis of the femoral head. This devastating complication occurs in 10-45% of femoral neck fractures. Therefore, it is vital for orthopedic surgeons provide efficient treatment of this injury, in order to optimize the patient's potential outcome and prevent long-term sequelae...
December 2018: Journal of Orthopaedics
R P Bogers, A van Gils, S C S Clahsen, W Vercruijsse, I van Kamp, C Baliatsas, J G M Rosmalen, J F B Bolte
BACKGROUND: Everyday exposure to radiofrequency electromagnetic fields (RF-EMF) emitted from wireless devices such as mobile phones and base stations, radio and television transmitters is ubiquitous. Some people attribute non-specific physical symptoms (NSPS) such as headache and fatigue to exposure to RF-EMF. Most previous laboratory studies or studies that analyzed populations at a group level did not find evidence of an association between RF-EMF exposure and NSPS. OBJECTIVES: We explored the association between exposure to RF-EMF in daily life and the occurrence of NSPS in individual self-declared electrohypersensitive persons using body worn exposimeters and electronic diaries...
September 15, 2018: Environment International
Carolyn I Jacob, Katya Paskova
BACKGROUND: Thermal fat reduction technologies are leading the market for nonsurgical abdominal contouring. However, they are ideal principally for patients with fat bulges. OBJECTIVES: Our study investigates the effects of a novel nonthermal technology affecting the abdominal musculature and subcutaneous adipose tissue. MATERIALS AND METHODS: A total of 22 patients (avg. BMI 23.8 kg m-2 ) underwent 4 treatments on abdomen with high-intensity focused electromagnetic (HIFEM) field device...
September 17, 2018: Journal of Cosmetic Dermatology
Xin Li, Joseph V Rispoli
PURPOSE: To facilitate assessment of RF power deposition and temperature rise within the breast, we present a method to seamlessly join heterogeneous breast models with standard whole-body models and demonstrate simulations at 7 T. METHODS: Finite-difference time-domain electromagnetic and bioheat simulations are performed to analyze the specific absorption rate (SAR) and temperature rise distributions in 36 Breast Imaging Reporting and Data System (BI-RADS) categorized breast models fused to 2 female whole-body models while transmitting from a 7T breast volume coil...
September 14, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Pim W van Egmond, Jore H Willems, Kees Jan Ponsen, Bart J Burger
Orthopaedic surgeons and trauma surgeons in the Netherlands are implanting 65,000 joint replacements and treating nearly 300,000 fractures per year. For many travellers with a metal implant - but also for the physicians who are treating them - it is unclear what the consequences will be when they have to go through airport security checks. These checks follow a fixed procedure in accordance with European rules which involves travellers passing through a number of visible and invisible barriers. The first barrier is usually a metal detector or a millimetre wave scanner; when the implant has been detected, this is followed by a body search...
August 20, 2018: Nederlands Tijdschrift Voor Geneeskunde
Hamad M Alkhoori, Akhlesh Lakhtakia, James K Breakall, Craig F Bohren
The extended boundary condition method can be used to study plane-wave scattering by an ellipsoid composed of an orthorhombic dielectric-magnetic material whose relative permittivity dyadic is a scalar multiple of its relative permeability dyadic. The scattered and internal field phasors can be expanded in terms of appropriate vector spherical wavefunctions with unknown expansion coefficients, whereas the incident-field phasors can be similarly expanded but with known expansion coefficients. The scattered-field coefficients are related to the incident-field coefficients through a matrix...
September 1, 2018: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Aman S Aberra, Angel V Peterchev, Warren M Grill
OBJECTIVE: We implemented computational models of human and rat cortical neurons for simulating the neural response to cortical stimulation with electromagnetic fields. APPROACH: We adapted model neurons from the library of Blue Brain models to reflect biophysical and geometric properties of both adult rat and human cortical neurons and coupled the model neurons to exogenous electric fields (E-fields). The models included 3D reconstructed axonal and dendritic arbors, experimentally-validated electrophysiological behaviors, and multiple, morphological variants within cell types...
August 21, 2018: Journal of Neural Engineering
Can Hu, Jie Feng, Sherman Xuegang Xin
Numerical electromagnetic models that can mimic the dielectric properties of human tissues have been widely used for dosimetry-related studies in bio-electromagnetics, particularly for the calculation of electromagnetic field distribution inside the human body, which is subject specific. Reports indicated that considerable electromagnetic field variations may occur inside different human subjects even when existing differences in the geometrical dimensions of these subjects are minimal. Therefore, a subject-specific three-dimensional (3D) electromagnetic model is crucially required to calculate the electromagnetic field distribution accurately...
July 31, 2018: Computers in Biology and Medicine
Prashanth S Venkataram, Jan Hermann, Alexandre Tkatchenko, Alejandro W Rodriguez
Thermal radiative phenomena can be strongly influenced by the coupling of phonons and long-range electromagnetic fields at infrared frequencies. Typically employed macroscopic descriptions of thermal fluctuations often ignore atomistic effects that become relevant at nanometric scales, whereas purely microscopic treatments ignore long-range, geometry-dependent electromagnetic effects. We describe a mesoscopic framework for modeling thermal fluctuation phenomena among molecules near macroscopic bodies, conjoining atomistic treatments of electronic and vibrational fluctuations obtained from density functional theory in the former with continuum descriptions of electromagnetic scattering in the latter...
July 27, 2018: Physical Review Letters
Mathias Davids, Bastien Guérin, Axel Vom Endt, Lothar R Schad, Lawrence L Wald
PURPOSE: As gradient performance increases, peripheral nerve stimulation (PNS) is becoming a significant constraint for fast MRI. Despite its impact, PNS is not directly included in the coil design process. Instead, the PNS characteristics of a gradient are assessed on healthy subjects after prototype construction. We attempt to develop a tool to inform coil design by predicting the PNS thresholds and activation locations in the human body using electromagnetic field simulations coupled to a neurodynamic model...
August 9, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Federica Facchin, Eva Bianconi, Silvia Canaider, Valentina Basoli, Pier Mario Biava, Carlo Ventura
The human body constantly regenerates after damage due to the self-renewing and differentiating properties of its resident stem cells. To recover the damaged tissues and regenerate functional organs, scientific research in the field of regenerative medicine is firmly trying to understand the molecular mechanisms through which the regenerative potential of stem cells may be unfolded into a clinical application. The finding that some organisms are capable of regenerative processes and the study of conserved evolutionary patterns in tissue regeneration may lead to the identification of natural molecules of ancestral species capable to extend their regenerative potential to human tissues...
2018: Stem Cells International
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