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Electromagnetic Fields

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https://www.readbyqxmd.com/read/28454162/three-dimensional-electromagnetic-gaussian-schell-model-sources
#1
Olga Korotkova, Lutful Ahad, Tero Setälä
We introduce three-dimensional (3D) stationary, electromagnetic Gaussian Schell-model (GSM) sources in the space-frequency domain and derive the realizability conditions that the source parameters must obey. In particular, we extend to 3D GSM sources two approaches to the realizability conditions presented previously for beam-like GSM sources. The results are of interest in the analysis and synthesis of tunable non-paraxial, partially coherent, partially polarized light fields.
May 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28454137/dynamic-stark-shift-induced-by-a-single-photon-packet
#2
D Valente, F Brito, T Werlang
The dynamic Stark shift results from the interaction of an atom with the electromagnetic field. We show how a propagating single-photon wave packet can induce a time-dependent dynamical Stark shift on a two-level system (TLS). A non-perturbative fully quantum treatment is employed, where the quantum dynamics of both the field and the TLS are analyzed. We also provide the means to experimentally access such time-dependent frequency by measuring the interference pattern in the electromagnetic field inside a 1D waveguide...
May 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28454038/long-term-variations-measurement-of-electromagnetic-field-exposures-in-alcal%C3%A3-de-henares-spain
#3
R Sánchez-Montero, C Alén-Cordero, P L López-Espí, J M Rigelsford, F Aguilera-Benavente, J Alpuente-Hermosilla
Electromagnetic radiowave exposure is a major concern in most countries due to possible adverse health effects. Over the last 10years, many technological changes (digital television, mobile technologies, wireless networks…) have led to variations in the electromagnetic field (EMF) levels. A large number of studies devoted to the analysis of EMF levels with personal dosimeters or computer models of the exposure of mobile stations have been conducted. However, the study of the exposure values, taking into account all the existing sources, and their evolution in a wide area, using measurements, has rarely been performed...
April 25, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28454013/mri-related-magnetic-field-exposures-and-risk-of-commuting-accidents-a-cross-sectional-survey-among-dutch-imaging-technicians
#4
Anke Huss, Kristel Schaap, Hans Kromhout
BACKGROUND: Imaging technicians working with magnetic resonance imaging (MRI) may experience acute effects such as vertigo or dizziness when being exposed. A previous study also reported an increased risk of accidents in MRI exposed staff. OBJECTIVES: We aimed at evaluating commuting accident risk in Dutch imaging technicians. METHODS: Of invited imaging technicians, 490 (29%) filled in a questionnaire pertaining to (near) accidents when driving or riding a bike, health, lifestyle and work practices...
April 25, 2017: Environmental Research
https://www.readbyqxmd.com/read/28448445/horizontal-directional-drilling-length-detection-technology-while-drilling-based-on-bi-electro-magnetic-sensing
#5
Yudan Wang, Guojun Wen, Han Chen
The drilling length is an important parameter in the process of horizontal directional drilling (HDD) exploration and recovery, but there has been a lack of accurate, automatically obtained statistics regarding this parameter. Herein, a technique for real-time HDD length detection and a management system based on the electromagnetic detection method with a microprocessor and two magnetoresistive sensors employing the software LabVIEW are proposed. The basic principle is to detect the change in the magnetic-field strength near a current coil while the drill stem and drill-stem joint successively pass through the current coil forward or backward...
April 27, 2017: Sensors
https://www.readbyqxmd.com/read/28447616/high-order-harmonics-measured-by-the-photon-statistics-of-the-infrared-driving-field-exiting-the-atomic-medium
#6
N Tsatrafyllis, I K Kominis, I A Gonoskov, P Tzallas
High-order harmonics in the extreme-ultraviolet spectral range, resulting from the strong-field laser-atom interaction, have been used in a broad range of fascinating applications in all states of matter. In the majority of these studies the harmonic generation process is described using semi-classical theories which treat the electromagnetic field of the driving laser pulse classically without taking into account its quantum nature. In addition, for the measurement of the generated harmonics, all the experiments require diagnostics in the extreme-ultraviolet spectral region...
April 27, 2017: Nature Communications
https://www.readbyqxmd.com/read/28442705/model-of-electrical-activity-in-cardiac-tissue-under-electromagnetic-induction
#7
Fuqiang Wu, Chunni Wang, Ying Xu, Jun Ma
Complex electrical activities in cardiac tissue can set up time-varying electromagnetic field. Magnetic flux is introduced into the Fitzhugh-Nagumo model to describe the effect of electromagnetic induction, and then memristor is used to realize the feedback of magnetic flux on the membrane potential in cardiac tissue. It is found that a spiral wave can be triggered and developed by setting specific initials in the media, that is to say, the media still support the survival of standing spiral waves under electromagnetic induction...
December 23, 2016: Scientific Reports
https://www.readbyqxmd.com/read/28440987/-tumors-of-the-central-nervous-system
#8
Marco Antonio Alegría-Loyola, Javier Andrés Galnares-Olalde, Moisés Mercado
Central nervous system (CNS) tumors constitute a heterogeneous group of neoplasms that share a considerable morbidity and mortality rate. Recent advances in the underlying oncogenic mechanisms of these tumors have led to new classification systems, which, in turn, allow for a better diagnostic approach and therapeutic planning. Most of these neoplasms occur sporadically and several risk factors have been found to be associated with their development, such as exposure to ionizing radiation or electromagnetic fields and the concomitant presence of conditions like diabetes, hypertension and Parkinson's disease...
May 2017: Revista Médica del Instituto Mexicano del Seguro Social
https://www.readbyqxmd.com/read/28437910/excitation-enhancement-in-electric-multipole-transitions-near-a-nanoedge
#9
Kosuke Shibata, Satoshi Tojo, Daniel Bloch
We investigate enhancement of electric multipole excitations of atoms in the vicinity of an object with a nanoscale edge resulted from a large electromagnetic field gradient. We calculate the excitation efficiencies of a Rb atom around a nanoedge and find the excitations are enhanced by several orders of magnitude. The efficiencies with the change in the magnetic quantum number resolved are also examined. Each resolved efficiency shows rotationally symmetric spatial distribution, with continuous modification in shape from the far field to the near field...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28435113/microsurgical-and-endoscopic-anatomy-for-intradural-temporal-bone-drilling-and-applications-of-the-electromagnetic-navigation-system-various-extensions-of-the-retrosigmoid-approach
#10
Ken Matsushima, Noritaka Komune, Satoshi Matsuo, Michihiro Kohno
OBJECTIVE: The use of the retrosigmoid approach has recently been expanded by several modifications including the suprameatal, transmeatal, suprajugular, and inframeatal extensions. Intradural temporal bone drilling without damaging vital structures inside or beside the bone, such as the internal carotid artery and jugular bulb, is a key step for these extensions. This study aimed to examine the microsurgical and endoscopic anatomy of the extensions of the retrosigmoid approach, and to evaluate the clinical feasibility of an electromagnetic navigation system during intradural temporal bone drilling...
April 20, 2017: World Neurosurgery
https://www.readbyqxmd.com/read/28434113/precision-knockdown-of-egfr-gene-expression-using-radio-frequency-electromagnetic-energy
#11
Ilya V Ulasov, Haidn Foster, Mike Butters, Jae-Geun Yoon, Tomoko Ozawa, Theodore Nicolaides, Xavier Figueroa, Parvinder Hothi, Michael Prados, John Butters, Charles Cobbs
Electromagnetic fields (EMF) in the radio frequency energy (RFE) range can affect cells at the molecular level. Here we report a technology that can record the specific RFE signal of a given molecule, in this case the siRNA of epidermal growth factor receptor (EGFR). We demonstrate that cells exposed to this EGFR siRNA RFE signal have a 30-70% reduction of EGFR mRNA expression and ~60% reduction in EGFR protein expression vs. control treated cells. Specificity for EGFR siRNA effect was confirmed via RNA microarray and antibody dot blot array...
April 22, 2017: Journal of Neuro-oncology
https://www.readbyqxmd.com/read/28431626/sleep-patterns-in-villagers-and-urban-african-volunteers-in-a-humid-tropical-climate-influence-of-accessibility-to-electric-light
#12
Alain Buguet, Pascal Bogui, Stéphane Picot, Raymond Cespuglio
Recent publications focusing on sleep-wake alternation, using actigraphic recordings in hunter-gatherers, stressed the existence of a potential effect of electricity availability on sleep habits. These reports prompted us to achieve a new analysis of the polysomnographic data already obtained in healthy African volunteers in equatorial Africa during two different investigations. Comparison of the 24-h polysomnographic sleep patterns were done between 9 volunteers sleeping in a laboratory in Abidjan (Abidjan cohort) and 11 villagers living in electricity-free bush villages (Sinfra cohort)...
May 15, 2017: Journal of the Neurological Sciences
https://www.readbyqxmd.com/read/28430501/metric-independence-of-vacuum-and-force-free-electromagnetic-fields
#13
Abraham I Harte
Electromagnetic fields which solve the vacuum Maxwell equations in one spacetime are well known to also be solutions in all spacetimes with conformally related metrics. This provides a sense in which electromagnetism alone cannot be used to measure certain aspects of geometry. We show that there is actually much more which cannot be so measured; relatively little of a spacetime's geometry is in fact imprinted in any particular electromagnetic field. This is demonstrated by finding a much larger class of metric transformations-involving five free functions-which preserve Maxwell solutions both in vacuum, without local currents, and also for the force-free electrodynamics associated with a tenuous plasma...
April 7, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28430370/extremely-low-frequency-electromagnetic-field-elf-emf-reduces-oxidative-stress-and-improves-functional-and-psychological-status-in-ischemic-stroke-patients
#14
Natalia Cichoń, Michał Bijak, Elżbieta Miller, Joanna Saluk
As a result of ischaemia/reperfusion, massive generation of reactive oxygen species occurs, followed by decreased activity of antioxidant enzymes. Extremely low frequency electromagnetic fields (ELF-EMF) can modulate oxidative stress, but there are no clinical antioxidant studies in brain stroke patients. The aim of our study was to investigate the effect of ELF-EMF on clinical and antioxidant status in post-stroke patients. Fifty-seven patients were divided into two groups: ELF-EMF and non-ELF-EMF. Both groups underwent the same 4-week rehabilitation program...
April 21, 2017: Bioelectromagnetics
https://www.readbyqxmd.com/read/28430275/concave-gold-bipyramids-bound-with-multiple-high-index-facets-improved-raman-and-catalytic-activities
#15
Xiaolin Kang, Qifeng Ruan, Han Zhang, Feng Bao, Jun Guo, Minghua Tang, Si Cheng, Jianfang Wang
Concave nanocrystals usually exhibit a large electromagnetic-field enhancement and superior catalytic performance due to their sharp corners, negative curvature and high-index facets. Conventional gold bipyramids (AuBPs) possess intriguing plasmonic properties which are attractive for various applications while the surface curvature of the reported bipyramids has not been fine-tuned to concave or convex structures to date. Additionally, the longitudinal surface plasmon resonance (LSPR) wavelengths of conventional AuBPs are mostly located in the range of 650-1350 nm and the sizes of these nanoparticles are usually not beyond 350 nm, which are not facilitated to some nano-focusing and nanophotonic applications...
April 21, 2017: Nanoscale
https://www.readbyqxmd.com/read/28429681/microwave-diathermy-in-physiotherapy-units-a-survey-on-spatial-and-time-heterogeneity-of-electromagnetic-field
#16
Andreas Andrikopoulos, Adam Adamopoulos, Ioannis Seimenis, Constantinos Miltiadis Koutsojannis
Microwave diathermy (MWD) is a therapeutic system that is in use for some decades now in all physiotherapy settings, according to national facility establishment regulations. Diathermy devices probably lack validity, as working time passes, introducing the need of control/reset of the device by qualified personnel, in order to maintain its effectiveness in sessions and accurately deliver the energy output the physiotherapist asks for. However, while in the field of physical therapy MWD has been a vital part for practicing the profession of physiotherapist, there is not a clear evidence of health burden due to incorrect usability...
April 21, 2017: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
https://www.readbyqxmd.com/read/28428549/low-noise-time-resolved-optical-sensing-of-electromagnetic-pulses-from-petawatt-laser-matter-interactions
#17
T S Robinson, F Consoli, S Giltrap, S J Eardley, G S Hicks, E J Ditter, O Ettlinger, N H Stuart, M Notley, R De Angelis, Z Najmudin, R A Smith
We report on the development and deployment of an optical diagnostic for single-shot measurement of the electric-field components of electromagnetic pulses from high-intensity laser-matter interactions in a high-noise environment. The electro-optic Pockels effect in KDP crystals was used to measure transient electric fields using a geometry easily modifiable for magnetic field detection via Faraday rotation. Using dielectric sensors and an optical fibre-based readout ensures minimal field perturbations compared to conductive probes and greatly limits unwanted electrical pickup between probe and recording system...
April 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28426435/surface-plasmon-resonance-in-gold-nanoparticles-a-review
#18
Vincenzo Amendola, Roberto Pilot, Marco Frasconi, Onofrio M Maragò, Maria Antonia Iatì
In the last two decades, plasmon resonance in gold nanoparticles (Au NPs) has been the subject of intense research efforts. Plasmon physics is intriguing and its precise modelling proved to be challenging. In fact, plasmons are highly responsive to a multitude of factors, either intrinsic to the Au NPs or from the environment, and recently the need emerged for the correction of standard electromagnetic approaches with quantum effects. Applications related to plasmon absorption and scattering in Au NPs are impressively numerous, ranging from sensing to photothermal effects to cell imaging...
May 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28426196/chiral-inorganic-nanostructures
#19
Wei Ma, Liguang Xu, André F de Moura, Xiaoling Wu, Hua Kuang, Chuanlai Xu, Nicholas A Kotov
The field of chiral inorganic nanostructures is rapidly expanding. It started from the observation of strong circular dichroism during the synthesis of simple nanoparticles (NPs) and their assemblies mediated by biomolecules and expanded to sophisticated synthetic protocols involving nanostructures from metals, semiconductors, ceramics, and nanocarbons. Besides the well-established chirality transfer from bioorganic molecules, other methods to impart handedness to nanoscale matter specific to inorganic materials were discovered, including three-dimentional lithography, multiphoton chirality transfer, polarization effects in nanoscale assemblies, and others...
April 20, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28426166/acute-effects-of-radiofrequency-electromagnetic-field-emitted-by-mobile-phone-on-brain-function
#20
REVIEW
Jun Zhang, Alexander Sumich, Grace Y Wang
Due to its attributes, characteristics, and technological resources, the mobile phone (MP) has become one of the most commonly used communication devices. Historically, ample evidence has ruled out the substantial short-term impact of radiofrequency electromagnetic field (RF-EMF) emitted by MP on human cognitive performance. However, more recent evidence suggests potential harmful effects associated with MP EMF exposure. The aim of this review is to readdress the question of whether the effect of MP EMF exposure on brain function should be reopened...
April 20, 2017: Bioelectromagnetics
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