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Electromagnetic field

Silvia de Miguel-Bilbao, Juan Blas, Victoria Ramos
A well-defined experimental procedure is put forward to evaluate maximum exposure conditions in a worst-case scenario whilst avoiding the uncertainties caused by the use of personal exposimeters (PEMs) as measuring devices: the body shadow effect (BSE), the limited sensitivity range, and the non-identification of the radiation source. An upper bound for exposure levels to EMF in several indoor enclosures has been measured and simulated. The frequency used for the study is 2.4 GHz, as it is the most commonly used band in indoor communications...
May 2, 2018: Journal of Visualized Experiments: JoVE
José M Caridad, Sinead Winters, David McCloskey, Georg S Duesberg, John F Donegan, Vojislav Krstić
The optical response of metallic nanohelices is mainly governed by a longitudinal localized surface plasmon resonance (LSPR) which arises due to the helical anisotropy of the system. Up to now, experimental studies have predominantly addressed the far-field response, despite the fact that the LSPR being of broad interest for converting incoming light into strongly enhanced (chiral) optical near-fields. Here, we demonstrate the control and spatial reproducibility of the plasmon-induced electromagnetic near-field around metallic nanohelices via surface-enhanced Raman scattering...
May 21, 2018: Nanotechnology
Gilad Haran, Lev Chuntonov
Plasmonic molecules are small assemblies of nanosized metal particles. Interactions between the particles modify their optical properties and make them attractive for multiple applications in spectroscopy and sensing. In this review, we focus on basic properties rather than on applications. Plasmonic molecules can be created using either nanofabrication methods or self-assembly techniques in solution. The interaction of plasmonic molecules with light leads to excitations that are classified using the concept of normal modes...
May 21, 2018: Chemical Reviews
Wenbing Li
The physics models of plasmonics for single nanoparticle, complex single nanoparticle, nanodimer, and single nanoparticle over a metallic thin film with an isolation layer, have been reviewed in this article. In nanoscale, the localized plasmonics from the single nanoparticle, hybrid single nanoparticle, and nanodimer, can be illustrated by classical electrodynamics. When the space of a nanodimer downs to subnanometer, the classical electrodynamics would fail to predict the resonance spectrum or dispersion of the nanostructures...
2018: Plasmonics
Astrid L Martens, Marije Reedijk, Tjabe Smid, Anke Huss, Danielle Timmermans, Maciej Strak, Wim Swart, Virissa Lenters, Hans Kromhout, Robert Verheij, Pauline Slottje, Roel C H Vermeulen
BACKGROUND: Psychosocial research has shown that perceived exposure can influence symptom reporting, regardless of actual exposure. The impact of this phenomenon on the interpretation of results from epidemiological research on environmental determinants of symptoms is unclear. OBJECTIVE: Our aim was to compare associations between modeled exposures, the perceived level of these exposures and reported symptoms (non-specific symptoms, sleep disturbances, and respiratory symptoms) for three different environmental exposures (radiofrequency electromagnetic fields (RF-EMF), noise, and air pollution)...
May 17, 2018: Science of the Total Environment
M Kiani, A Abdolali, M Safari
In this article, an analytical approach is presented for the analysis of electromagnetic (EM) scattering from radially inhomogeneous spherical structures (RISSs) based on the duality principle. According to the spherical symmetry, similar angular dependencies in all the regions are considered using spherical harmonics. To extract the radial dependency, the system of differential equations of wave propagation toward the inhomogeneity direction is equated with the dual planar ones. A general duality between electromagnetic fields and parameters and scattering parameters of the two structures is introduced...
March 2018: Physical Review. E
James S Gaynor, Sean Hagberg, Blake T Gurfein
Pulsed electromagnetic field (PEMF) therapy can non-invasively treat a variety of pathologies by delivering electric and magnetic fields to tissues via inductive coils. The electromagnetic fields generated by these devices have been found to affect a variety of biological processes and basic science understanding of the underlying mechanisms of action of PEMF treatment has accelerated in the last 10 years. Accumulating clinical evidence supports the use of PEMF therapy in both animals and humans for specific clinical indications including bone healing, wound healing, osteoarthritis and inflammation, and treatment of post-operative pain and edema...
May 7, 2018: Research in Veterinary Science
Yukun Yin, Ping Chen, Qiang Yu, Yan Peng, ZeHao Zhu, Jing Tian
BACKGROUND A low frequency pulsed electromagnetic field (PEMF) has been confirmed to play an important role in promoting the osteogenic differentiation of human bone marrow stem cells (BMSCs). Adipose-derived stem cells (ASCs) possess some attractive characteristics for clinical application compared to BMSCs, such as abundant stem cells from lipoaspirates, faster growth, less discomfort and morbidity during surgery. ASCs can become adipocytes, osteoblasts, chondrocytes, myocytes, neurocytes, and other cell types...
May 18, 2018: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
Hiie Hinrikus, Maie Bachmann, Jaanus Lass
PURPOSE: This topic review aims to explain the mechanism of low-level microwave radiation effect based on published research results. The review presents the analysis of theoretical and experimental results comprising underlying physics and derived biological-physiological consequences supported by experimental data. CONCLUSIONS: The rotation of dipolar molecules causes polarization of dielectric medium and restructuring of hydrogen bonds between these molecules...
May 18, 2018: International Journal of Radiation Biology
Kyosuke Sakai, Takeaki Yamamoto, Keiji Sasaki
The spatial structure of an electromagnetic field can determine the characteristics of light-matter interactions. A strong gradient of light in the near field can excite dipole-forbidden atomic transitions, e.g., electric quadrupole transitions, which are rarely observed under plane-wave far-field illumination. Structured light with a higher-order orbital angular momentum state may also modulate the selection rules in which an atom can absorb two quanta of angular momentum: one from the spin and another from the spatial structure of the beam...
May 17, 2018: Scientific Reports
Kubra Boz, Hayri Hakan Denli
The rapid development of the global system for mobile communication services and the consequent increased electromagnetic field (EMF) exposure to the human body have generated debate on the potential danger with respect to human health. The many research studies focused on this subject have, however, not provided any certain evidence about harmful consequences due to mobile communication systems. On the other hand, there are still views suggesting such exposure might affect the human body in different ways...
May 7, 2018: Geospatial Health
Oliver Burman, Gerardo Marsella, Angelo Di Clemente, Luigi Cervo
Electromagnetic field (EMF) technology has the potential to improve scientific data capture and welfare assessment by allowing automated data collection from individual cages. However, it is important to determine any impact that a new technology itself may have on animal welfare, and previous studies have found contrasting results of EMF on laboratory rodent anxiety-like behaviour and cognition. We therefore investigated whether there was an effect of low frequency EMF experienced continuously over a six-week period, as an integral part of the animal housing system, on measures of mouse anxiety-related behaviour, cognition and welfare...
2018: PloS One
Maria Timofeeva, Lukas Lang, Flavia Timpu, Claude Renaut, Alexei Bouravleuv, Igor V Shtrom, George Cirlin, Rachel Grange
Nonradiating electromagnetic configurations in nanostructures open new horizons for applications due to two essential features: lack of energy losses and invisibility to the propagating electromagnetic field. Such radiationless configurations form a basis for new types of nanophotonic devices, where a strong electromagnetic field confinement can be achieved together with lossless interactions between nearby components. In our work, we present a new design of free-standing disk nanoantennas with nonradiating current distributions for the optical near-infrared range...
May 17, 2018: Nano Letters
Yan Zhao, Sarawuth Chaimool
In this paper, we apply a relativistic finite-difference time-domain (FDTD) method by using the Lorentz transformation to analyze metamaterials moving at a high speed. As an example, we consider a slab of left-handed metmaterial (LHM) with both relative permittivity and permeability equal to -1. Simulation results show that when the LHM slab moves at a high speed, its electromagnetic responses are drastically different from the static case. Specifically, when the LHM slab moves toward the source, for the case of normal incidence, there exists a special velocity at which fields experience a zero spatial phase delay through the LHM slab; while for the oblique incidence, above a certain velocity fields inside the LHM become evanescent...
May 16, 2018: Scientific Reports
E Mitsai, A Kuchmizhak, E Pustovalov, A Sergeev, A Mironenko, S Bratskaya, D P Linklater, A Balčytis, E Ivanova, S Juodkazis
All-dielectric resonant micro- and nano-structures made of high-index dielectrics have recently emerged as a promising surface-enhanced Raman scattering (SERS) platform which can complement or potentially replace the metal-based counterparts in routine sensing measurements. These unique structures combine the highly-tunable optical response and high field enhancement with the non-invasiveness, i.e. chemically non-perturbing the analyte, simple chemical modification and recyclability. Meanwhile, commercially competitive fabrication technologies for mass production of such structures are still missing...
May 16, 2018: Nanoscale
Susanne Mayer-Wagner, Florian Hammerschmid, Helmut Blum, Stefan Krebs, Julia I Redeker, Boris M Holzapfel, Volkmar Jansson, Peter E Müller
Introduction: Low frequency electromagnetic fields (LF-EMF) and simulated microgravity (SMG) have been observed to affect chondrogenesis. A controlled bioreactor system was developed to apply LF-EMF and SMG singly or combined during chondrogenic differentiation of human mesenchymal stem cells (hMSCs) in 3D culture. Material and methods: An external motor gear SMG bioreactor was combined with magnetic Helmholtz coils for EMF (5 mT; 15 Hz). Pellets of hMSCs (±TGF-β3) were cultured (P5) under SMG, LF-EMF, LF-EMF/SMG and control (1 g) conditions for 3 weeks...
April 2018: Archives of Medical Science: AMS
Carlos Sánchez Muñoz, Franco Nori, Simone De Liberato
Recent technological developments have made it increasingly easy to access the non-perturbative regimes of cavity quantum electrodynamics known as ultrastrong or deep strong coupling, where the light-matter coupling becomes comparable to the bare modal frequencies. In this work, we address the adequacy of the broadly used single-mode cavity approximation to describe such regimes. We demonstrate that, in the non-perturbative light-matter coupling regimes, the single-mode models become unphysical, allowing for superluminal signalling...
May 15, 2018: Nature Communications
Sonja M Schellhammer, Sebastian Gantz, Armin Lühr, Bradley M Oborn, Michael Bussmann, Aswin L Hoffmann
PURPOSE: Given its sensitivity to anatomical variations, proton therapy is expected to benefit greatly from integration with magnetic resonance imaging for on-line anatomy monitoring during irradiation. Such an integration raises several challenges, as both systems mutually interact. The proton beam will experience quasi-continuous energy loss and energy-dependent electromagnetic deflection at the same time, giving rise to a deflected beam trajectory and an altered dose distribution with a displaced Bragg peak...
May 15, 2018: Medical Physics
Pavlo O Sukhachov, E V Gorbar, Igor A Shovkovy, V A Miransky
The spectrum of collective excitations in Weyl materials is studied by using a consistent hydrodynamics. The corresponding framework includes the vortical and chiral anomaly effects, as well as the dependence on the separations between the Weyl nodes in energy b<sub>0</sub> and momentum <b>b</b>. The latter are introduced via the Chern--Simons contributions to the electric current and charge densities in Maxwell's equations. It is found that, even in the absence of a background magnetic field, certain collective excitations (e...
May 15, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Meng Li, Shasha Liu, Yingyan Jiang, Wei Wang
In a typical bipolar electrochemistry (BPE) configuration, voltage applied between the two driving electrodes induced a potential drop through solution filled in the microchannel, resulting in interfacial potential difference between solution and BPE varied along the BPE. In the present work, we employed a recently-developed plasmonic imaging technique to map the distribution of surface potential of bipolar electrodes with various geometries including round, triangle, hexagon, star and rhombus shapes under non-faradaic charging process, from which the line of zero potential (LZP) was visualized and determined...
May 15, 2018: Analytical Chemistry
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