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https://www.readbyqxmd.com/read/29145005/assessment-of-long-term-spatio-temporal-radiofrequency-electromagnetic-field-exposure
#1
Sam Aerts, Joe Wiart, Luc Martens, Wout Joseph
As both the environment and telecommunications networks are inherently dynamic, our exposure to environmental radiofrequency (RF) electromagnetic fields (EMF) at an arbitrary location is not at all constant in time. In this study, more than a year's worth of measurement data collected in a fixed low-cost exposimeter network distributed over an urban environment was analysed and used to build, for the first time, a full spatio-temporal surrogate model of outdoor exposure to downlink Global System for Mobile Communications (GSM) and Universal Mobile Telecommunications System (UMTS) signals...
November 13, 2017: Environmental Research
https://www.readbyqxmd.com/read/29144283/large-purcell-enhancement-with-efficient-one-dimensional-collection-via-coupled-nanowire-nanorod-system
#2
Xueke Duan, Juanjuan Ren, Fan Zhang, He Hao, Guowei Lu, Qihuang Gong, Ying Gu
Combining the advantages of both gap surface plasmons and evanescent waves, we demonstrate simultaneously large Purcell enhancement and efficient one- dimensional collection of photons at subwavelength scale in the coupled nanowire- nanorod system. The spontaneous emission can be enhanced by thousands of times based on the excitation of gap surface plasmons with strongly localized electromagnetic field. Emitted photons are directly collected by subwavelength-confined evanescent modes and guided along the nanowire...
November 16, 2017: Nanotechnology
https://www.readbyqxmd.com/read/29143352/assessment-of-exposure-to-radio-frequency-electromagnetic-fields-from-smart-utility-meters-in-gb-part-ii-numerical-assessment-of-induced-sar-within-the-human-body
#3
Muhammad R A Qureshi, Yasir Alfadhl, Xiaodong Chen, Azadeh Peyman, Myron Maslanyj, Simon Mann
Human body exposure to radiofrequency electromagnetic waves emitted from smart meters was assessed using various exposure configurations. Specific energy absorption rate distributions were determined using three anatomically realistic human models. Each model was assigned with age- and frequency-dependent dielectric properties representing a collection of age groups. Generalized exposure conditions involving standing and sleeping postures were assessed for a home area network operating at 868 and 2,450 MHz...
November 16, 2017: Bioelectromagnetics
https://www.readbyqxmd.com/read/29140354/enhancement-of-raman-scattering-of-a-gaseous-medium-near-the-surface-of-a-silver-holographic-grating
#4
Dmitry V Petrov, Alexey R Zaripov, Nikita A Toropov
The Letter demonstrates a possibility to enhance the Raman scattering of a gaseous medium due to an enhanced electromagnetic field caused by the excitation of propagating surface plasmon polaritons (PSPPs) on a silver holographic grating. Efficiency of collinear and noncollinear schemes of PSPP excitation on a metal-gaseous medium interface was studied. When using a collinear scheme, we registered an eightfold enhancement of the Raman scattering of atmospheric nitrogen and oxygen, where the average gain near the PSPP-active surface was ∼4×10(3)...
November 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/29139285/subradiant-dipolar-interactions-in-plasmonic-nanoring-resonator-array-for-integrated-label-free-biosensing
#5
Yuzhang Liang, Hui Zhang, Wenqi Zhu, Amit Agrawal, Henri J Lezec, Lixia Li, Wei Peng, Yi Zou, Yan-Qing Lu, Ting Xu
With the development of advanced nanofabrication technologies over the last decade, plasmonic nanostructures have attracted wide attention for their potential in label-free biosensing applications. However, the sensing performance of nanostructured plasmonic sensors is primarily limited by the broad-linewidth features with low peak-to-dip signal ratio in the extinction spectra that result from strong radiative damping. Here, we propose and systematically investigate the in-plane and out-of-plane dipolar interactions in an array of plasmonic nanoring resonators that are from the spatial combination of classic nanohole and nanodisk structures...
November 15, 2017: ACS Sensors
https://www.readbyqxmd.com/read/29138675/benign-effect-of-extremely-low-frequency-electromagnetic-field-on-brain-plasticity-assessed-by-nitric-oxide-metabolism-during-poststroke-rehabilitation
#6
Natalia Cichoń, Piotr Czarny, Michał Bijak, Elżbieta Miller, Tomasz Śliwiński, Janusz Szemraj, Joanna Saluk-Bijak
Nitric oxide (NO) is one of the most important signal molecules, involved in both physiological and pathological processes. As a neurotransmitter in the central nervous system, NO regulates cerebral blood flow, neurogenesis, and synaptic plasticity. The aim of our study was to investigate the effect of the extremely low-frequency electromagnetic field (ELF-EMF) on generation and metabolism of NO, as a neurotransmitter, in the rehabilitation of poststroke patients. Forty-eight patients were divided into two groups: ELF-EMF and non-ELF-EMF...
2017: Oxidative Medicine and Cellular Longevity
https://www.readbyqxmd.com/read/29138434/generating-localized-plasmonic-fields-on-an-integrated-photonic-platform-using-tapered-couplers-for-biosensing-applications
#7
Gurpreet Singh, Renzhe Bi, U S Dinish, Malini Olivo
A theoretical design and analysis of a tapered-coupler structure on a silicon nitride integrated-photonic platform for coupling optical energy from a dielectric waveguide to a plasmonic tip is presented. The proposed design can be considered as a hybrid photonic-plasmonic structure that generally supports hybrid symmetric and asymmetric modes. Along the taper, one of the hybrid modes approaches the cut-off, while the other approaches the short-range surface plasmon mode that generates localized fields. Potential use of the proposed novel tapered-coupler plasmonic structure for highly sensitive biosensing applications using surface enhanced Raman scattering (SERS) and metal enhanced fluorescence (MEF) techniques is discussed...
November 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29138310/sparsity-enables-estimation-of-both-subcortical-and-cortical-activity-from-meg-and-eeg
#8
Pavitra Krishnaswamy, Gabriel Obregon-Henao, Jyrki Ahveninen, Sheraz Khan, Behtash Babadi, Juan Eugenio Iglesias, Matti S Hämäläinen, Patrick L Purdon
Subcortical structures play a critical role in brain function. However, options for assessing electrophysiological activity in these structures are limited. Electromagnetic fields generated by neuronal activity in subcortical structures can be recorded noninvasively, using magnetoencephalography (MEG) and electroencephalography (EEG). However, these subcortical signals are much weaker than those generated by cortical activity. In addition, we show here that it is difficult to resolve subcortical sources because distributed cortical activity can explain the MEG and EEG patterns generated by deep sources...
November 14, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29134998/2d-molybdenum-and-vanadium-nitrides-synthesized-by-ammoniation-of-2d-transition-metal-carbides-mxenes
#9
Patrick Urbankowski, Babak Anasori, Kanit Hantanasirisakul, Long Yang, Lihua Zhang, Bernard Haines, Steven J May, Simon J L Billinge, Yury Gogotsi
MXenes are a rapidly growing class of 2D transition metal carbides and nitrides, finding applications in fields ranging from energy storage to electromagnetic interference shielding and transparent conductive coatings. However, while more than 20 carbide MXenes have already been synthesized, Ti4N3 and Ti2N are the only nitride MXenes reported so far. Here by ammoniation of Mo2CTx and V2CTx MXenes at 600 °C, we report on their transformation to 2D metal nitrides. Carbon atoms in the precursor MXenes are replaced with N atoms, resulting from the decomposition of ammonia molecules...
November 14, 2017: Nanoscale
https://www.readbyqxmd.com/read/29133925/absorption-and-extinction-cross-sections-and-photon-streamlines-in-the-optical-near-field
#10
Moritz Striebel, Jӧrg Wrachtrup, Ilja Gerhardt
The optical interaction of light and matter is modeled as an oscillating dipole in a plane wave electromagnetic field. We analyze absorption, scattering and extinction for this system by the energy flow, visualized as streamlines of the Poynting vector. Depending on the dissipative damping of the oscillator, a part of the streamlines ends up in the dipole. Based on a graphical investigation of the streamlines, this represents the absorption cross section, and forms a far-field absorption aperture. In the near-field of the oscillator, a modification of the aperture is observed...
November 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29131166/achieving-electric-field-focusing-using-annular-metal-dielectric-multilayers
#11
Feng Wu
We present studies on an electric field focuser comprised of annular epsilon-near-zero metamaterials (ENZMs) and inner free space. According to effective medium theory, annular ENZMs can be realized via annular metal-dielectric multilayers. In practice, we choose silver and air to design the focuser. Our numerical simulations demonstrate that the electric field can be focused on a fixed point, regardless of the number and location of electromagnetic sources in annular multilayers, which might be helpful for laser ignition...
November 10, 2017: Applied Optics
https://www.readbyqxmd.com/read/29129601/on-chip-signal-amplification-of-magnetic-bead-based-immunoassay-by-aviating-magnetic-bead-chains
#12
Uddin M Jalal, Gyeong Jun Jin, Kyu Shik Eom, Min Ho Kim, Joon S Shim
In this work, a Lab-on-a-Chip (LOC) platform is used to electromagnetically actuate magnetic bead chains for an enhanced immunoassay. Custom-made electromagnets generate a magnetic field to form, rotate, lift and lower the magnetic bead chains (MBCs). The cost-effective, disposable LOC platform was made with a polymer substrate and an on-chip electrochemical sensor patterned via the screen-printing process. The movement of the MBCs is controlled to improve the electrochemical signal up to 230% when detecting beta-type human chorionic gonadotropin (β-hCG)...
November 6, 2017: Bioelectrochemistry
https://www.readbyqxmd.com/read/29129049/dna-origami-directed-au-nanostar-dimers-for-single-molecule-surface-enhanced-raman-scattering
#13
Swati Tanwar, Krishna Haldar, Tapasi Sen
We demonstrate the synthesis of Au nanostar dimer with tunable interparticle gap and controlled stoichiometry as-sembled on DNA origami. Au nanostars with uniform and sharp tips were immobilized on rectangular DNA origami dimerized structures to create nanoantennas containing monomeric and dimeric Au nanostars. Single Texas red dye was specifically attached in the junction of the dimerized origami which acts as a Raman reporter molecule. The SERS enhancement factors of single Texas red dye located in the conjunction region in the dimer structures having inter-particle gaps of 7 nm and 13 nm are 2 × 1010 and 8 × 109, respectively, which are strong enough for single analyte detec-tion...
November 13, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29125197/iei-emf-provocation-case-studies-a-novel-approach-to-testing-sensitive-individuals
#14
Adam Verrender, Sarah P Loughran, Vitas Anderson, Lena Hillert, G James Rubin, Gunnhild Oftedal, Rodney J Croft
The etiology of Idiopathic Environmental Intolerance attributed to Electromagnetic Fields (IEI-EMF) is controversial. While the majority of studies have indicated that there is no relationship between EMF exposure and symptoms reported by IEI-EMF sufferers, concerns about methodological issues have been raised. Addressing these concerns, the present experiment was designed as a series of individual case studies to determine whether there is a relationship between radiofrequency-electromagnetic field (RF-EMF) exposure and an IEI-EMF individual's self-reported symptoms...
November 10, 2017: Bioelectromagnetics
https://www.readbyqxmd.com/read/29125193/exposure-to-a-specific-time-varying-electromagnetic-field-inhibits-cell-proliferation-via-camp-and-erk-signaling-in-cancer-cells
#15
Carly A Buckner, Alison L Buckner, Stan A Koren, Michael A Persinger, Robert M Lafrenie
Exposure to specific electromagnetic field (EMF) patterns can affect a variety of biological systems. We have shown that exposure to Thomas-EMF, a low-intensity, frequency-modulated (25-6 Hz) EMF pattern, inhibited growth and altered cell signaling in malignant cells. Exposure to Thomas-EMF for 1 h/day inhibited the growth of malignant cells including B16-BL6 mouse melanoma cells, MDA-MB-231, MDA-MB-468, BT-20, and MCF-7 human breast cancer and HeLa cervical cancer cells but did not affect non-malignant cells...
November 10, 2017: Bioelectromagnetics
https://www.readbyqxmd.com/read/29124476/aligned-chemically-etched-silver-nanowire-monolayer-as-surface-enhanced-raman-scattering-substrates
#16
Jianchao Wang, Hongsheng Luo, Minghai Zhang, Xihong Zu, Zhiwei Li, Guobin Yi
Silver nanowires (AgNWs) were chemically etched to significantly increase the surface roughness and then self-assembled on the liquid/gas interfaces via the interfacial assembly method to obtain aligned chemically etched silver nanowire films. The as-fabricated silver nanowire films were used as novel surface-enhanced Raman scattering (SERS) substrates. The morphologies and plasmon characteristics of the substrates were investigated using multiple measurement methods. The performance of as-fabricated substrates was measured using rhodamine B as a probe...
November 9, 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/29121397/virtual-phantom-magnetic-resonance-imaging-vip-mri-on-a-clinical-mri-platform
#17
Hervé Saint-Jalmes, Alejandro Bordelois, Giulio Gambarota
PURPOSE: To implement Virtual Phantom Magnetic Resonance Imaging (ViP MRI), a technique that allows for generating reference signals in MR images using radiofrequency (RF) signals, on a clinical MR system and to test newly designed virtual phantoms. METHODS: MRI experiments were conducted on a 1.5 T MRI scanner. Electromagnetic modelling of the ViP system was done using the Principle of Reciprocity. The ViP RF signals were generated using a compact waveform generator (dimensions of 26cm x 18cm x 16cm), connected to a home-built 25mm-diameter RF coil...
November 9, 2017: Medical Physics
https://www.readbyqxmd.com/read/29119962/-the-specific-features-of-the-development-of-metabolic-and-regenerative-processes-under-the-action-of-low-intensity-electromagnetic-radiation-in-radiation-exposure-conditions-an-experimental-study
#18
Yu N Korolev, L V Mihajlik, L A Nikulina, M S Geniatulina
The experiments on male white rats with the use of biochemical, photo-optical, and electron-microscopic techniques have demonstrated that the use of low-intensity electromagnetic radiation of ultrahigh frequency (EMR UHF) and low-intensity low-frequency magnetic field (MF) during the post-irradiation period (within 21 days after exposure to radiation) enhanced the metabolic and regenerative processes in the testes and liver. It was shown that the application of MF largely intensified the antioxidant activity whereas EMR UHF preferentially stimulated the biosynthetic processes as well as the processes of cellular and intracellular regeneration...
2017: Voprosy Kurortologii, Fizioterapii, i Lechebnoĭ Fizicheskoĭ Kultury
https://www.readbyqxmd.com/read/29119785/plasmonic-near-field-localization-of-silver-core-shell-nanoparticle-assemblies-via-wet-chemistry-nanogap-engineering
#19
Ramesh Asapu, Radu-George Ciocarlan, Nathalie Claes, Natan Blommaerts, Matthias Minjauw, Tareq Ahmad, Jolien Dendooven, Pegie Cool, Sara Bals, Siegfried Denys, Christophe Detavernier, Silvia Lenaerts, Sammy W Verbruggen
Silver nanoparticles are widely used in the field of plasmonics because of their unique optical properties. The wavelength-dependent surface plasmon resonance gives rise to a strongly enhanced electromagnetic field, especially at so-called hot spots located in the nanogap in-between metal nanoparticle assemblies. Therefore, the interparticle distance is a decisive factor in plasmonic applications, such as surface-enhanced Raman spectroscopy (SERS). In this study, the aim is to engineer this interparticle distance for silver nanospheres using a convenient wet-chemical approach and to predict and quantify the corresponding enhancement factor using both theoretical and experimental tools...
November 16, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29119574/effects-of-emf-emissions-from-undersea-electric-cables-on-coral-reef-fish
#20
Audie K Kilfoyle, Robert F Jermain, Manhar R Dhanak, Joseph P Huston, Richard E Spieler
The objective of this study was to determine if electromagnetic field (EMF) emissions from undersea power cables impacted local marine life, with an emphasis on coral reef fish. The work was done at the South Florida Ocean Measurement Facility of Naval Surface Warfare Center in Broward County, Florida, which has a range of active undersea detection and data transmission cables. EMF emissions from a selected cable were created during non-destructive visual fish surveys on SCUBA. During surveys, the transmission of either alternating current (AC), direct current (DC), or none (OFF) was randomly initiated by the facility at a specified time...
November 9, 2017: Bioelectromagnetics
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