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Electromagnetic Radiation

Sven Augustin, Sven Frohmann, Peter Jung, Heinz-Wilhelm Hübers
Terahertz (THz) radiation meaning electromagnetic radiation in the range from 0.1 (3) to 10 (30) has the unique advantage of easily penetrating many obstructions while being non-hazardous to organic tissue since it is non-ionizing. A shortcoming of this domain is the limited availability of high-sensitivity detector arrays respective THz cameras with >1k pixels. To overcome the imaging limitations of the THz domain, compressive imaging in combination with an optically controllable THz spatial light modulator is a promising approach especially when used in a single-pixel imaging modality...
March 20, 2018: Scientific Reports
Esben S Worm, Morten Høyer, Rune Hansen, Lars P Larsen, Britta Weber, Cai Grau, Per R Poulsen
PURPOSE: Intrafraction motion can compromise the treatment accuracy in liver stereotactic body radiation therapy (SBRT). Respiratory gating can improve treatment delivery; however, gating based on external motion surrogates is inaccurate. The present study reports the use of Calypso-based internal electromagnetic motion monitoring for gated liver SBRT. METHODS AND MATERIALS: Fifteen patients were included in a study of 3-fraction respiratory gated liver SBRT guided by 3 implanted electromagnetic transponders...
February 13, 2018: International Journal of Radiation Oncology, Biology, Physics
L Bua, E Tibaldi, L Falcioni, M Lauriola, L De Angelis, F Gnudi, M Manservigi, F Manservisi, I Manzoli, I Menghetti, R Montella, S Panzacchi, D Sgargi, V Strollo, A Vornoli, D Mandrioli, F Belpoggi
BACKGROUND: Up to now, experimental studies on rodents have failed to provide definitive confirmation of the carcinogenicity of extremely low frequency electromagnetic fields (ELFEMF). Two recent studies performed in our laboratory on Sprague-Dawley rats reported a statistically significant increase in malignant tumors of different sites (mammary gland, C-cells carcinoma, hemolymphoreticular neoplasia, and malignant heart Schwannoma) when ELFEMF exposure was associated with exposure to formaldehyde (50 mg/l) or acute low dose of γ-radiation (0...
March 14, 2018: Environmental Research
Andrzej T Slominski, Michal A Zmijewski, Przemyslaw M Plonka, Jerzy P Szaflarski, Ralf Paus
The skin, a self-regulating protective barrier organ, is empowered with sensory and computing capabilities to counteract the environmental stressors to maintain/restore disrupted cutaneous homeostasis. These complex functions are coordinated by a cutaneous neuro-endocrine system that also communicates in a bidirectional fashion with the central nervous, endocrine and immune systems, all acting in concert to control body homeostasis. While ultraviolet energy (UV) has played an important role in the origin and evolution of life, UV absorption by the skin not only triggers mechanisms that defend skin integrity and regulate global homeostasis, but also induces skin pathology (e...
March 12, 2018: Endocrinology
Paul J Keall, Emma Colvill, Ricky O'Brien, Vincent Caillet, Thomas Eade, Andrew Kneebone, George Hruby, Per R Poulsen, Benjamin Zwan, Peter B Greer, Jeremy Booth
PURPOSE: To report on the primary and secondary outcomes of a prospective clinical trial of electromagnetic-guided multileaf collimator (MLC) tracking radiation therapy for prostate cancer. METHODS AND MATERIALS: Twenty-eight men with prostate cancer were treated with electromagnetic-guided MLC tracking with volumetric modulated arc therapy. A total of 858 fractions were delivered, with the dose per fraction ranging from 2 to 13.75 Gy. The primary outcome was feasibility, with success determined if >95% of fractions were successfully delivered...
February 6, 2018: International Journal of Radiation Oncology, Biology, Physics
Jan Powers, Michael Luebbehusen, Lillian Aguirre, Julia Cluff, Mary Ann David, Vince Holly, Lorraine Linford, Nancy Park, Rocco Brunelle
BACKGROUND: Early enteral nutrition has been shown to decrease complications and improve patient outcomes. Post pyloric feeding is recommended for patients with gastric intolerance or at high risk for aspiration. Feeding tube placement can be challenging and pose risk of pulmonary complications. Reliance on radiographic confirmation for feeding tube placement exposes the patient to radiation. Electromagnetic placement device (EMPD) may offer a method to minimize pulmonary complications, increase successful placement, and decrease radiation exposure to the patient...
March 12, 2018: Nutrition in Clinical Practice
Giuseppe Curcio
In the past 20 years of research regarding effects of mobile phone-derived electromagnetic fields (EMFs) on human cognition, attention has been one of the first and most extensively investigated functions. Different domains investigated covered selective, sustained, and divided attention. Here, the most relevant studies on this topic have been reviewed and discussed. A total of 43 studies are reported and summarized: of these, 31 indicated a total absence of statistically significant difference between real and sham signal, 9 showed a partial improvement of attentional performance (mainly increase in speed of performance and/or improvement of accuracy) as a function of real exposure, while the remaining 3 showed inconsistent results (i...
2018: Frontiers in Public Health
Zohreh Vafapour
Recently reported metamaterial (MM) analogs of electromagnetically induced reflectance (EIR) enable a unique route to endow classical optical structures with aspects of quantum optical systems. This method opens up many fascinating prospects on novel optical components, such as slow light units, highly sensitive sensors, and nonlinear devices. Here we designed and simulated a microwave MM made from aluminum thin film to mimic the EIR system. High reflectance of about 99 percent and also a large group index at the reflectance window of about 243 are demonstrated, which mainly arise from the enhanced coupling between radiative and nonradiative elements...
March 1, 2018: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Isahar Gabay, Amir Shemer, Ariel Schwarz, Zeev Zalevsky
In this paper, we present an advanced two-dimensional (2D) novel microwave photonic approach to super-resolved radar imaging. Unlike synthetic aperture radar that requires movement to improve resolution by synthetically increasing the antenna's dimensions, our super-resolved imaging solution not only does not require movement to synthetically increase the antenna's dimensions, it also allows this super-resolved sensing with only a single (mono) detector. The operation principle is based upon phased array antennas, which consist of four radiating horn antennas that generate a projected plane at the far field zone...
March 1, 2018: Applied Optics
Evgeny Karashtin, Andrey Fraerman
We report a theoretical study of the second harmonic generation in a noncollinearly magnetized conductive medium with equilibrium spin current. The hydrodynamic model is used to unravel the mechanism of a novel effect of the double frequency signal generation that is attributed to the spin current. According to our calculations, this second harmonic response appears due to the ``non-adiabatic'' spin polarization of the conduction electrons induced by the oscillations in the non-uniform magnetization forced by the electric field of the electromagnetic wave...
March 9, 2018: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Kamran Akbari, Zoran L Miskovic, Silvina Segui, Juana Gervasoni, Néstor Ricardo Arista
We analyze the energy loss channels for a fast charged particle traversing a multi-layer graphene (MLG) structure with N layers under normal incidence. Focusing on a terahertz (THz) range of frequencies, and assuming equally doped graphene layers with a large enough separation d between them to neglect interlayer electron hopping, we use the Drude model for two-dimensional conductivity of each layer to describe hybridization of graphene's Dirac plasmon polaritons (DPPs). Performing a layer decomposition of ohmic energy losses, which include excitation of hybridized DPPs (HDPPs), we have found for N=3 that the middle HDPP eigenfrequency is not excited in the middle layer due to symmetry constraint, whereas the excitation of the lowest HDPP eigenfrequency produces a Fano resonance in the graphene layer that is first traversed by the charged particle...
March 8, 2018: Nanotechnology
Piotr Targowski, Magdalena Iwanicka, Marcin Sylwestrzak, Cecilia Frosinini, Jana Striova, Raffaella Fontana
Optical Coherence Tomography (OCT) was used for non-invasive examination of a well-known, yet complex, painting from the studio of Leonardo da Vinci in combination with routine imaging in various bands of electromagnetic radiation. In contrast with these techniques, OCT provides depth-resolved information. Three post-processing modalities were explored: cross-sectional views, maps of scattering from given depths, and their 3D models. Some hidden alterations of the painting due to past restorations were traced: retouching and overpainting with their positioning within varnish layers as well as indications of a former transfer to canvas...
March 7, 2018: Angewandte Chemie
Eranezhuth Wasan Awin, Abhijeet Lale, Kollamala Chellappan Nair Hari Kumar, Umit Bilge Demirci, Samuel Bernard, Ravi Kumar
Titania (TiO₂) is considered to have immense potential as a photocatalyst, the anatase phase in particular. There have been numerous attempts to push the limits of its catalytic activity to higher wavelengths to harness the visible electromagnetic radiation. Most of the investigations till date have been restricted to fine-tuning the bandgap by doping, control of defect chemistry at the surface and several to first principle simulations either with limited success or success at the cost of complexities in processing...
March 1, 2018: Materials
Juan Lei, Juxing Yang, Xi Chen, Zhiya Zhang, Guang Fu, Yang Hao
Transformation Optics has been proven a versatile technique for designing novel electromagnetic devices and it has much wider applicability in many subject areas related to general wave equations. Among them, quasi-conformal transformation optics (QCTO) can be applied to minimize anisotropy of transformed media and has opened up the possibility to the design of broadband antennas with arbitrary geometries. In this work, a wide-angle scanning conformal phased array based on all-dielectric QCTO lens is designed and experimentally demonstrated...
February 28, 2018: Scientific Reports
Xiaodong Feng, Sen Gong, Renbin Zhong, Tao Zhao, Min Hu, Chao Zhang, Shenggang Liu
In this Letter, the enhanced and directional radiation in a wide terahertz (THz) frequency range in a graphene hyperbolic medium excited by an electric dipole is presented. The numerical simulations and theoretical analyses indicate that the enhanced radiation comes from the strong surface plasmon couplings in the graphene hyperbolic medium, consisting of alternative graphene and dielectric substrate layers. The simulation results also show that the peak power flow of the enhanced THz radiation in the graphene hyperbolic medium is dramatically enhanced by more than 1 order of magnitude over that in a general medium within a certain distance from the dipole, and the electromagnetic fields are strongly concentrated in a narrow angle...
March 1, 2018: Optics Letters
Ivana Kolmašová, Ondřej Santolík, Eric Defer, William Rison, Sylvain Coquillat, Stéphane Pedeboy, Radek Lán, Luděk Uhlíř, Dominique Lambert, Jean-Pierre Pinty, Serge Prieur, Véronique Pont
We analyze lightning initiation process using magnetic field waveforms of preliminary breakdown (PB) pulses observed at time scales of a few tens of microseconds by a broad-band receiver. We compare these pulses with sources of narrow-band very high frequency (VHF) radiation at 60-66 MHz recorded by two separate Lightning Mapping Arrays (LMAs). We find that almost none of the observed PB pulses correspond to geo-located VHF radiation sources, in agreement with previous results and with the hypothesis that processes generating VHF radiation and PB pulses are only weakly related...
February 26, 2018: Scientific Reports
Matthew R Buckley, Anthony DiFranzo
The distributions of dark matter and baryons in the Universe are known to be very different: The dark matter resides in extended halos, while a significant fraction of the baryons have radiated away much of their initial energy and fallen deep into the potential wells. This difference in morphology leads to the widely held conclusion that dark matter cannot cool and collapse on any scale. We revisit this assumption and show that a simple model where dark matter is charged under a "dark electromagnetism" can allow dark matter to form gravitationally collapsed objects with characteristic mass scales much smaller than that of a Milky-Way-type galaxy...
February 2, 2018: Physical Review Letters
Chiara Carla Piccinetti, Alfredo De Leo, Gloria Cosoli, Lorenzo Scalise, Basilio Randazzo, Graziano Cerri, Ike Olivotto
The augmented exposure of both environment and human being to electromagnetic waves and the concomitant lack of an unequivocal knowledge about biological consequences of these radiations, raised public interest on electromagnetic pollution. In this context, the present study aims to evaluate the biological effects on zebrafish (ZF) embryos of 100 MHz radiofrequency electromagnetic field (RF-EMF) exposure through a multidisciplinary protocol. Because of the shared synteny between human and ZF genomes that validated its use in biomedical research, toxicology and developmental biology studies, ZF was here selected as experimental model and a measurement protocol and biological analyses have been set up to clearly discriminate between RF-EMF biological and thermal effects...
February 21, 2018: Ecotoxicology and Environmental Safety
Tobias N Wistisen, Antonino Di Piazza, Helge V Knudsen, Ulrik I Uggerhøj
Quantum radiation reaction is the influence of multiple photon emissions from a charged particle on the particle's dynamics, characterized by a significant energy-momentum loss per emission. Here we report experimental radiation emission spectra from ultrarelativistic positrons in silicon in a regime where quantum radiation reaction effects dominate the positron's dynamics. Our analysis shows that while the widely used quantum approach is overall the best model, it does not completely describe all the data in this regime...
February 23, 2018: Nature Communications
Francesco Ciampa, Pooya Mahmoodi, Fulvio Pinto, Michele Meo
Active infrared thermography is a fast and accurate non-destructive evaluation technique that is of particular relevance to the aerospace industry for the inspection of aircraft and helicopters' primary and secondary structures, aero-engine parts, spacecraft components and its subsystems. This review provides an exhaustive summary of most recent active thermographic methods used for aerospace applications according to their physical principle and thermal excitation sources. Besides traditional optically stimulated thermography, which uses external optical radiation such as flashes, heaters and laser systems, novel hybrid thermographic techniques are also investigated...
February 16, 2018: Sensors
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