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https://www.readbyqxmd.com/read/28817289/how-to-drive-a-flashing-electron-ratchet-to-maximize-current
#1
Ofer Kedem, Bryan Lau, Emily A Weiss
Biological systems utilize a combination of asymmetry, noise, and chemical energy to produce motion in the highly damped environment of the cell with molecular motors, many of which are "ratchets", non-equilibrium devices for producing directed transport using non-directional perturbations, without a net bias. The underlying ratchet principle has been implemented in man-made micro- and nano-devices, to transport charged particles by oscillating an electric potential with repeating asymmetric features. In this experimental study, the ratcheting of electrons in an organic semiconductor is optimized by tuning the temporal modulation of the oscillating potential, applied using nanostructured electrodes...
August 17, 2017: Nano Letters
https://www.readbyqxmd.com/read/28808279/fine-tuning-and-mond-in-a-metamaterial-multiverse
#2
Igor I Smolyaninov, Vera N Smolyaninova
We consider the recently suggested model of a multiverse based on a ferrofluid. When the ferrofluid is subjected to a modest external magnetic field, the nanoparticles inside the ferrofluid form small hyperbolic metamaterial domains, which from the electromagnetic standpoint behave as individual "Minkowski universes" exhibiting different "laws of physics", such as different strength of effective gravity, different versions of modified Newtonian dynamics (MOND) and different radiation lifetimes. When the ferrofluid "multiverse" is populated with atomic or molecular species, and these species are excited using an external laser source, the radiation lifetimes of atoms and molecules in these "universes" depend strongly on the individual physical properties of each "universe" via the Purcell effect...
August 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28805193/optics-of-plasmon-exciton-nanomaterials
#3
Maxim Sukharev, Abraham Nitzan
This review provides a brief introduction to the physics of coupled exciton-plasmon systems, the theoretical description and experimental manifestation of such phenomena, followed by an account of the state-of-the-art methodology for the numerical simulations of such phenomena and supplemented by a number of FORTRAN codes, by which the interested reader can introduce himself/herself to the practice of such simulations. Applications to CW light scattering as well as transient response and relaxation are described...
August 14, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28801909/promoter-activation-with-electromagnetism
#4
Abraham O Rodríguez-De la Fuente, J Antonio Heredia-Rojas, Juan M Alcocer-González, Laura E Rodríguez-Flores, Cristina Rodríguez-Padilla, Reyes S Taméz-Guerra
Gene expression can be modified by physical factors, such as heat, electricity and magnetic fields , and several types of ionizing and non-ionizing radiation. Promoter activation with extremely low-frequency electromagnetic fields is possible with an appropriate promoter, containing electromagnetic field response elements. Here, we describe how to examine promoter activation with extremely low-frequency electromagnetic fields, and we provide a step-by-step guide to the assembly of a solenoid suitable for promoter activation...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28799671/hydrophobic-flexible-and-lightweight-mxene-foams-for-high-performance-electromagnetic-interference-shielding
#5
Ji Liu, Hao-Bin Zhang, Renhui Sun, Yafeng Liu, Zhangshuo Liu, Aiguo Zhou, Zhong-Zhen Yu
Ultrathin, lightweight, and flexible electromagnetic-interference (EMI) shielding materials are urgently required to manage increasingly serious radiation pollution. 2D transition-metal carbides (MXenes) are considered promising alternatives to graphene for providing excellent EMI-shielding performance due to their outstanding metallic electrical conductivity. However, the hydrophilicity of MXene films may affect their stability and reliability when applied in moist or wet environments. Herein, for the first time, an efficient and facile approach is reported to fabricate freestanding, flexible, and hydrophobic MXene foam with reasonable strength by assembling MXene sheets into films followed by a hydrazine-induced foaming process...
August 11, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28799651/thermal-mapping-on-male-genital-and-skin-tissues-of-laptop-thermal-sources-and-electromagnetic-interaction
#6
Mahdi Safari, Navid Mosleminiya, Ali Abdolali
Since the development of communication devices and expansion of their applications, there have been concerns about their harmful health effects. The main aim of this study was to investigate laptop thermal effects caused by exposure to electromagnetic fields and thermal sources simultaneously; propose a nondestructive, replicable process that is less expensive than clinical measurements; and to study the effects of positioning any new device near the human body in steady state conditions to ensure safety by U...
August 11, 2017: Bioelectromagnetics
https://www.readbyqxmd.com/read/28796645/on-the-use-of-particle-filters-for-electromagnetic-tracking-in-high-dose-rate-brachytherapy
#7
Theresa Ida Götz, Godehard Lahmer, Tobias Brandt, Karoline Kallis, Vratislav Strnad, Christoph Bert, Bernhard Hensel, Ana Maria Tome, Elmar W Lang
Modern radiotherapy of female breat cancers often employ high dose rate Brachytherapy, where a radioactive source is moved inside catheters, implanted in the female breast, according to a prescribed treatment plan. Source localization relative to the patient's anatomy is determined with solenoid sensors whose spatial positions are measured with an electromagnetic tracking system. Precise sensor dwell position determination is of utmost importance to assure irradiation of the cancerous tissue according to the treatment plan...
August 10, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28790393/on-the-dynamic-toroidal-multipoles-from-localized-electric-current-distributions
#8
Ivan Fernandez-Corbaton, Stefan Nanz, Carsten Rockstuhl
We analyze the dynamic toroidal multipoles and prove that they do not have an independent physical meaning with respect to their interaction with electromagnetic waves. We analytically show how the split into electric and toroidal parts causes the appearance of non-radiative components in each of the two parts. These non-radiative components, which cancel each other when both parts are summed, preclude the separate determination of each part by means of measurements of the radiation from the source or of its coupling to external electromagnetic waves...
August 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28773948/dielectric-characteristics-and-microwave-absorption-of-graphene-composite-materials
#9
Kevin Rubrice, Xavier Castel, Mohamed Himdi, Patrick Parneix
Nowadays, many types of materials are elaborated for microwave absorption applications. Carbon-based nanoparticles belong to these types of materials. Among these, graphene presents some distinctive features for electromagnetic radiation absorption and thus microwave isolation applications. In this paper, the dielectric characteristics and microwave absorption properties of epoxy resin loaded with graphene particles are presented from 2 GHz to 18 GHz. The influence of various parameters such as particle size (3 µm, 6-8 µm, and 15 µm) and weight ratio (from 5% to 25%) are presented, studied, and discussed...
October 13, 2016: Materials
https://www.readbyqxmd.com/read/28762334/controlled-formation-of-gold-nanostructures-on-biopolymer-films-upon-electromagnetic-radiation
#10
Andrea Mescola, Claudio Canale, Despina Fragouli, Athanassia Athanassiou
The localized formation of gold nanostructures with controlled size and shape on chitosan films doped with gold precursor upon electromagnetic irradiation of various types is here demonstrated. Such controlled formation is achieved by tuning the wavelength, the energy and the interaction time of the radiation with the composite films. In particular, the use of a single UV nanosecond laser pulse results in the formation of gold sub-micron platelets with specific crystal structure, while increasing the number of pulses, further precursor reduction and photofragmentation induce the formation of gold nanoparticles...
August 1, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28760955/light-responsive-organic-flashing-electron-ratchet
#11
Ofer Kedem, Bryan Lau, Mark A Ratner, Emily A Weiss
Ratchets are nonequilibrium devices that produce directional motion of particles from nondirectional forces without using a bias, and are responsible for many types of biological transport, which occur with high yield despite strongly damped and noisy environments. Ratchets operate by breaking time-reversal and spatial symmetries in the direction of transport through application of a time-dependent potential with repeating, asymmetric features. This work demonstrates the ratcheting of electrons within a highly scattering organic bulk-heterojunction layer, and within a device architecture that enables the application of arbitrarily shaped oscillating electric potentials...
August 15, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28758796/on-the-origin-of-worries-about-modern-health-hazards-experimental-evidence-for-a-conjoint-influence-of-media-reports-and-personality-traits
#12
Michael Witthöft, Ina Freitag, Christiane Nußbaum, Anne-Kathrin Bräscher, Fabian Jasper, Josef Bailer, G James Rubin
OBJECTIVE: Worries about health threatening effects of potential health hazards of modern life (e.g. electric devices and pollution) represent a growing phenomenon in Western countries. Yet, little is known about the causes of this growing special case of affective risk perceptions termed Modern Health Worries (MHW). The purpose of this study is to examine a possible role of biased media reports in the formation of MHW. DESIGN: In two experiments, we investigated whether typical television reports affect MHW...
July 31, 2017: Psychology & Health
https://www.readbyqxmd.com/read/28755561/measurement-of-the-environmental-broadband-electromagnetic-waves-in-a-mid-size-european-city
#13
R Fernández-García, I Gil
In this paper, the level of exposure to broadband radiofrequency electromagnetic field in a mid-size European city was evaluated in accordance with the International Commission on Non-ionizing Radiation Protection guidelines from 1998. With the aim to analyse all the potential electromagnetic waves present in the city up to 18GHz, a total of 271 locations distributed along Terrassa (Spain) have been measured. To show the results in an easy-to-interpret way by the citizen, the results have been represented in a set of raster maps...
October 2017: Environmental Research
https://www.readbyqxmd.com/read/28748924/significant-and-variable-linear-polarization-during-the-prompt-optical-flash-of-grb-160625b
#14
E Troja, V M Lipunov, C G Mundell, N R Butler, A M Watson, S Kobayashi, S B Cenko, F E Marshall, R Ricci, A Fruchter, M H Wieringa, E S Gorbovskoy, V Kornilov, A Kutyrev, W H Lee, V Toy, N V Tyurina, N M Budnev, D A H Buckley, J González, O Gress, A Horesh, M I Panasyuk, J X Prochaska, E Ramirez-Ruiz, R Rebolo Lopez, M G Richer, C Román-Zúñiga, M Serra-Ricart, V Yurkov, N Gehrels
Newly formed black holes of stellar mass launch collimated outflows (jets) of ionized matter that approach the speed of light. These outflows power prompt, brief and intense flashes of γ-rays known as γ-ray bursts (GRBs), followed by longer-lived afterglow radiation that is detected across the electromagnetic spectrum. Measuring the polarization of the observed GRB radiation provides a direct probe of the magnetic fields in the collimated jets. Rapid-response polarimetric observations of newly discovered bursts have probed the initial afterglow phase, and show that, minutes after the prompt emission has ended, the degree of linear polarization can be as high as 30 per cent-consistent with the idea that a stable, globally ordered magnetic field permeates the jet at large distances from the central source...
July 26, 2017: Nature
https://www.readbyqxmd.com/read/28741207/evaluation-of-colour-temperatures-in-the-cultivation-of-dunaliella-salina-and-nannochloropsis-oculata-in-the-production-of-lipids-and-carbohydrates
#15
Salim Gabriel Pavón-Suriano, Luis Alfredo Ortega-Clemente, Sergio Curiel-Ramírez, María Isabel Jiménez-García, Ignacio Alejandro Pérez-Legaspi, Paula Natalia Robledo-Narváez
The production of biofuels from microalgae is a promising and sustainable alternative. Its production is determined by the content of lipids and carbohydrates, which is different for each microalgae species and is affected by environmental factors, being lighting one of the principal determining their biochemical composition. The colour temperature (electromagnetic radiation and light spectrum) is a determining factor for the production of lipids and carbohydrates in microalgae. The aim of this assay was to evaluate the effect of three colour temperatures (6500, 10,000 and 20,000 °K) on the biomass (cel mL(-1)), biomass production and productivity (g L(-1) and g L(-1) day(-1)), lipid and carbohydrate content (%), lipid and carbohydrate production and productivity (mg L(-1) and mg L(-1) day(-1)), composition and content of fatty acids (%) in two microalgae species: Dunaliella salina and Nannochloropsis oculata...
July 25, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28733683/radiation-loss-of-planar-surface-plasmon-polaritons-transmission-lines-at-microwave-frequencies
#16
Zhixia Xu, Shunli Li, Xiaoxing Yin, Hongxin Zhao, Leilei Liu
Radiation loss of a typical spoof surface plasmon polaritons (SSPPs) transmission line (TL) is investigated in this paper. A 325 mm-long SSPPs TL is designed and fabricated. Simulated results show that radiation loss contributes more to transmission loss than dielectric loss and conductor loss from 2 GHz to 10 GHz. Radiation loss of the SSPPs TL could be divided into two parts, one is caused by the input mode converter, and the other is caused by the corrugated metallic strip. This paper explains mechanisms of radiation loss from different parts, designs a loaded SSPPs TL with a series of resistors to absorb electromagnetic energy on corrugated metallic strip, and then discriminates radiation loss from the input mode converter, proposes the concept of average radiation length (ARL) to evaluate radiation loss from SSPPs of finite length, and concludes that radiation loss is mainly caused by corrugated structure of finite length at low frequency band and by the input mode converter at high frequency band...
July 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28733661/helical-phase-structure-of-radiation-from-an-electron-in-circular-motion
#17
M Katoh, M Fujimoto, N S Mirian, T Konomi, Y Taira, T Kaneyasu, M Hosaka, N Yamamoto, A Mochihashi, Y Takashima, K Kuroda, A Miyamoto, K Miyamoto, S Sasaki
We theoretically show that a single free electron in circular motion radiates an electromagnetic wave possessing helical phase structure, which is closely related to orbital angular momentum carried by it. We experimentally demonstrate it by interference and double-slit diffraction experiments on radiation from relativistic electrons in spiral motion. Our results indicate that photons carrying orbital angular momentum should be created naturally by cyclotron/synchrotron radiations or Compton scatterings in various situations in cosmic space...
July 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28729909/biological-effects-and-mechanisms-of-shortwave-radiation-a-review
#18
REVIEW
Chao Yu, Rui-Yun Peng
With the increasing knowledge of shortwave radiation, it is widely used in wireless communications, radar observations, industrial manufacturing, and medical treatments. Despite of the benefits from shortwave, these wide applications expose humans to the risk of shortwave electromagnetic radiation, which is alleged to cause potential damage to biological systems. This review focused on the exposure to shortwave electromagnetic radiation, considering in vitro, in vivo and epidemiological results that have provided insight into the biological effects and mechanisms of shortwave...
2017: Military Medical Research
https://www.readbyqxmd.com/read/28728442/an-integrated-platform-for-small-animal-hyperthermia-investigations-under-ultra-high-field-mri-guidance
#19
Sergio Curto, Pegah Faridi, Tej B Shrestha, Marla Pyle, Leila Maurmann, Deryl Troyer, Stefan H Bossmann, Punit Prakash
PURPOSE: Integrating small-animal experimental hyperthermia instrumentation with magnetic resonance imaging (MRI) affords real-time monitoring of spatial temperature profiles. This study reports on the development and preliminary in vivo characterisation of a 2.45 GHz microwave hyperthermia system for pre-clinical small animal investigations, integrated within a 14 T ultra-high-field MRI scanner. MATERIALS AND METHODS: The presented system incorporates a 3.5 mm (OD) directional microwave hyperthermia antenna, positioned adjacent to the small-animal target, radiating microwave energy for localised heating of subcutaneous tumours...
July 21, 2017: International Journal of Hyperthermia
https://www.readbyqxmd.com/read/28724940/dispersive-2d-cherenkov-radiation-on-a-dielectric-nano-film
#20
Weihao Liu
We report a modified two-dimensional Cherenkov radiation, which occurs on a high-index dielectric nano-film driven by uniformly moving electron-beam. It is essentially different from the ordinary Cherenkov radiation in that, in the nondispersive medium, it shows unique dispersion characteristics-the waves with higher frequencies radiate at larger Cherenkov angles. Its radiation frequency and direction are essentially determined by structure parameters as well as the beam-velocity. By means of fully electromagnetic simulations and theoretical analyses, we explored the mechanism and requirements of this radiation...
July 19, 2017: Scientific Reports
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