High Electromagnetic Field Research Articles

Short‐term exposure to a 1439‐MHz TDMA signal exerts no estrogenic effect in rats

The aim of this study was to elucidate the possible effects of short-term exposure to a 1439-MHz electromagnetic field (EMF) employing time division multiple access (TDMA), which is the basis of the Japanese Personal Digital Cellular system, on estrogenic activity in rats. Sixty-four ovariectomized female Sprague-Dawley rats were divided into four groups: EMF exposure (EM), sham exposure, cage control, and 17 beta-estradiol injected (E2). The EM group was exposed, for 4 h per day on three consecutive days, to the 1439-MHz TDMA signal that produced 5.5-6.1 and 0.88-0.99 W/kg average specific absorption rates in the brain and the whole body, respectively. The uterine wet mass and serum estradiol level significantly increased in the E2 group, while there were no differences among the other three groups. Although negative effects of long-term EMF exposure must be thoroughly investigated before a final conclusion can be reached, our results do not support the assumption that the high frequency EMF used in cellular phones exerts estrogenic activity.

Do cell phones truly impact cellular function?

OBJECTIVE: Cell phones (CP) have become almost essential to present-day life. However, recent studies have suggested CP are responsible for several medical conditions, including lower sperm counts. Yet, no real mechanism has been explained. Work from this lab has focused on the effects of electromagnetic fields (EMF) created by laboratory equipment on reproductive and other tissues. The objective of the present study was to determine if cells in vitro were affected by direct exposure to CP and to determine the radiant energy source responsible for the effect. DESIGN: Culture based study of the effects of CP on a macrophage cell model. MATERIALS AND METHODS: A review suggested that CP might emit either EMF or radio frequency radiation (RF), or both. To determine which fields were present, EMF and RF were measured from 67 cell phones. Preliminary culture experiments were then conducted using a murine macrophage model. Macrophages were recovered, placed in culture and allowed 24 h to attach to the culture surface. After 24 h, duplicate wells of cells were exposed to a high EMF (positive control), direct contact with cells phones, or no exposure (negative control). Then the cells were examined at 24 and 72 h to determine cell activation. RESULTS: Cell Phones produce little to no EMF, but produced a significant RF field (P < .001). The RF fields varied with phone type (P <.001) and state of activity. However, these fields could only be detected in immediate proximity to the phone equipment. Cells exposed to the EMF exhibited significant activation (P < .001) when compared to the control. Macrophages exposed to CP also exhibited significant activation (P < .001) over the control, but less that those exposed to the EMF. CONCLUSION: Radiant fields associated with cell phones do appear capable of inducing changes in cell activity. However the effect appears to require almost direct exposure of the cells to the source. Further research is needed to determine if a similar effects can be seen in reproductive cells in vitro or in vivo.

Exposure to GSM RF Fields Does Not Affect Calcium Homeostasis in Human Endothelial Cells, Rat Pheocromocytoma Cells or Rat Hippocampal Neurons

In the course of modern daily life, individuals are exposed to numerous sources of electromagnetic radiation that are not present in the natural environment. The strength of the electromagnetic fields from sources such as hairdryers, computer display units and other electrical devices is modest. However, in many home and office environments, individuals can experience perpetual exposure to an “electromagnetic smog”, with occasional peaks of relatively high electromagnetic field intensity. This has led to concerns that such radiation can affect health. In particular, emissions from mobile phones or mobile phone masts have been invoked as a potential source of pathological electromagnetic radiation. Previous reports have suggested that cellular calcium (Ca2+) homeostasis is affected by the types of radiofrequency fields emitted by mobile phones. In the present study, we used a high-throughput imaging platform to monitor putative changes in cellular Ca2+ during exposure of cells to 900 MHz GSM fields of differing power (specific absorption rate 0.012–2 W/Kg), thus mimicking the type of radiation emitted by current mobile phone handsets. Data from cells experiencing the 900 Mhz GSM fields were compared with data obtained from paired experiments using continuous wave fields or no field. We employed three cell types (human endothelial cells, PC-12 neuroblastoma and primary hippocampal neurons) that have previously been suggested to be sensitive to radiofrequency fields. Experiments were designed to examine putative effects of radiofrequency fields on resting Ca2+, in addition to Ca2+ signals evoked by an InsP3-generating agonist. Furthermore, we examined putative effects of radiofrequency field exposure on Ca2+ store emptying and store-operated Ca2+ entry following application of the Ca2+ATPase inhibitor thapsigargin. Multiple parameters (e.g., peak amplitude, integrated Ca2+ signal, recovery rates) were analysed to explore potential impact of radiofrequency field exposure on Ca2+ signals. Our data indicate that 900 MHz GSM fields do not affect either basal Ca2+ homeostasis or provoked Ca2+ signals. Even at the highest field strengths applied, which exceed typical phone exposure levels, we did not observe any changes in cellular Ca2+ signals. We conclude that under the conditions employed in our experiments, and using a highly-sensitive assay, we could not detect any consequence of RF exposure.

Synthetic Routes and Plasmonic Properties of Noble Metal Nanoplates

AbstractThis article provides an overview of recent research on the synthesis and surface‐plasmon‐related properties of noble metal nanoplates. The first part is dedicated to summarizing the most relevant wet‐chemical and physical synthetic protocols that have been used to obtain Au and Ag nanotriangles/nanoplates in high yield, with a discussion of the formation mechanisms proposed by the different authors. Finally, we present a description of the characteristic optical properties of nanoparticles with this particular morphology, in relation with the possibility of exciting different surface plasmon modes and concentrating high electromagnetic fields atcertain areas, which is important for applications in surface‐enhanced Raman scattering (SERS).

Ag@SiO2 Core−Shell Nanoparticles for Probing Spatial Distribution of Electromagnetic Field Enhancement via Surface-Enhanced Raman Scattering

We show that the spatial distribution of the electromagnetic (EM) field enhancement can be probed directly via dynamic evolution of surface-enhanced Raman scattering (SERS) of rhodamine 6G (R6G) molecules as they diffuse into Ag@SiO(2) core-shell nanoparticles. The porous silica shell limits the diffusion of R6G molecules toward inner Ag cores, thereby allowing direct observation and quantification of the spatial distribution of SERS enhancement as molecules migrate from the low to high EM fields inside the dielectric silica shell. Our experimental evidence is validated by the generalized Mie theory, and the approach can potentially offer a novel platform for further investigating the site and spatial distribution of the EM fields and the EM versus chemical enhancement of SERS due to molecular confinement within the Ag@SiO(2) nanoshell.

Stress-related endocrinological and psychopathological effects of short- and long-term 50 Hz electromagnetic field exposure in rats

It is believed that different electromagnetic fields do have beneficial and harmful biological effects. The aim of the present work was to study the long-term consequences of 50 Hz electromagnetic field (ELF-EMF) exposure with special focus on the development of chronic stress and stress-induced psychopathology. Adult male Sprague–Dawley rats were exposed to ELF-EMF (50 Hz, 0.5 mT) for 5 days, 8 h daily (short) or for 4–6 weeks, 24 h daily (long). Anxiety was studied in elevated plus maze test, whereas depression-like behavior of the long-treated group was examined in the forced swim test. Some days after behavioral examination, the animals were decapitated among resting conditions and organ weights, blood hormone levels as well as proopiomelanocortin mRNA level from the anterior lobe of the pituitary gland were measured. Both treatments were ineffective on somatic parameters, namely none of the changes characteristic to chronic stress (body weight reduction, thymus involution and adrenal gland hypertrophy) were present. An enhanced blood glucose level was found after prolonged ELF-EMF exposure ( p = 0.013). The hormonal stress reaction was similar in control and short-term exposed rats, but significant proopiomelanocortin elevation ( p < 0.000) and depressive-like behavior (enhanced floating time; p = 0.006) were found following long-term ELF-EMF exposure. Taken together, long and continuous exposure to relatively high intensity electromagnetic field may count as a mild stress situation and could be a factor in the development of depressive state or metabolic disturbances. Although we should stress that the average intensity of the human exposure is normally much smaller than in the present experiment.

Measurement of electromagnetic fields generated by air traffic control radar systems with spectrum analysers

Air traffic control (ATC) primary radars are 'classical' radars that use echoes of radiofrequency (RF) pulses from aircraft to determine their position. High-power RF pulses radiated from radar antennas may produce high electromagnetic field levels in the surrounding area. Measurement of electromagnetic fields produced by RF-pulsed radar by means of a swept-tuned spectrum analyser are investigated here. Measurements have been carried out both in the laboratory and in situ on signals generated by an ATC primary radar.

Recyclable Molecular Trapping and SERS Detection in Silver-Loaded Agarose Gels with Dynamic Hot Spots

We describe the design and fabrication of composite agarose gels, highly loaded with silver nanoparticles. Because the gel can collapse upon drying and recover when rehydrated, it can be foreseen as an excellent mechanical molecular trap that additionally gives rise to dynamic hot spots as the network volume decreases and the silver particles get close to each other, thereby generating the high electromagnetic fields that are needed for ultradetection. Additionally, as silver nanoparticles are physically trapped inside the polymer network, analytes can be washed out by dialysis when immersed in a washing solution, so that recycling can be achieved. Finally, the use of SERS for ultradetection of dichlorodiphenyl-trichloroethane (DDT) is reported for the first time, demonstrating the ability of this novel nanocomposite material to reversibly sequester nonconventional SERS analytes.

Electrochemical Control of the Time-Dependent Intensity Fluctuations in Surface-Enhanced Raman Scattering (SERS)

Time-dependent fluctuations in surface-enhanced Raman scattering (SERS) intensities were recorded from a roughened silver electrode immersed in diluted solutions of rhodamine 6G (R6G) and congo red (CR). These fluctuations were attributed to a small number of SERS-active molecules probing regions of extremely high electromagnetic field (hot spots) at the nanostructured surface. The time-dependent distribution of SERS intensities followed a tailed statistics at certain applied potentials, which has been linked to single-molecule dynamics. The shape of the distribution was reversibly tuned by the applied voltage. Mixtures of both dyes, R6G and CR, at low concentrations were also investigated. Since R6G is a cationic dye and CR is an anionic dye, the statistics of the SERS intensity distribution of either dye in a mixture were independently controlled by adjusting the applied potential. The potential-controlled distribution of SERS intensities was interpreted by considering the modulation of the surface coverage of the adsorbed dye by the interfacial electric field. This interpretation was supported by a two-dimensional Monte Carlo simulation that took into account the time evolution of the surface configuration of the adsorbed species and their probability to populate a hypothetical hot spot. The potential-controlled SERS dynamics reported here is a first step toward the spectroelectrochemical investigation of redox processes at the single-molecule level by SERS.

Improved 3D adaptive remeshing scheme applied in high electromagnetic field gradient computation

An improved adaptive remeshing process that allows the accurate control of the numerical solution of a partial differential 3D vectorial equation is introduced. It is applied to compute the electromagnetic intensity around a metallic sphere, which is known to present high gradients in limited zones of space. Thanks to the numerical results of an analytical model, we show that, the precision of the solution being controlled, this improved scheme permits to decrease drastically the computational time as well as the memory requirements by adapting the number and the position of nodes.

Analysis of the Mobile Phone Effect on the Heart Rate Variability by Using the Largest Lyapunov Exponent

In this study, the effects of electromagnetic fields (EMFs) emitted by GSM900 based mobile phones (MPs) on the heart rate variability (HRV) were examined by using nonlinear analysis methods. The largest Lyapunov exponent (LLE) calculation was used to evaluate the effect of MP under various real exposure conditions. Sixteen healthy young volunteers were exposed to EMFs emitted by GSM900 based MP at two levels from a very low EMF (MP at stand-by) to a higher EMF (MP at pre-ring handshaking and ringing). A blind experimental protocol was designed and utilized with consideration to the physiological and psychological factors that may affect HRV. The results showed that the LLE values increased slightly with higher EMF produced by MP (P < 0.05). This change indicates that the degree of chaos in the HRV signals increased at higher EMF compared to low level EMF. Consequently, we have concluded that high level EMF changed the complexity of cardiac system behavior, significantly.

Wireless Phones Electromagnetic Field Radiation Exposure Assessment

Problem statement: Inadequate knowledge of electromagnetic field emitted by mobile phones and increased usage at close proximity, created a lot of skepticism and speculations among end users on its safety or otherwise. Approach: In this study, near field electromagnetic field radiation measurements were conducted on different brand of mobile phones in active mode using a tri-axis isotropic probe and electric field meter. Results: The highest electromagnetic field exposure was recorded when the mobile phones are at outgoing call mode and backing the probe, which is higher in comparison to ICNIRP guidelines for exposure to general public. Conclusion: According to this finding, some mobile phones electromagnetic field radiation were found to be lower than the ICNIRP guidelines while some were far above the guidelines. Electromagnetic field intensity however, depends on the mode of operation and proximity of the mobile phones to the end user; hence it is safer to use mobile phones at SMS mode.

Enhanced SPR response from patterned immobilization of surface bioreceptors on nano-gratings

In this report, nano-gratings with guided adsorption of biomolecules are investigated as new transducer elements or biointerfaces for surface plasmon resonance biosensor technologies. SPR biosensors are of particular interest due to the interaction between the electromagnetic fields and periodic nano-structures. In this article, sensitivity enhancement is demonstrated for a surface plasmon resonance interface, in a Kretschmann's configuration, featuring nano-gratings combined with nano-patterned immobilization of surface bioreceptors. The fabrication of this enhanced biointerface is demonstrated using a combination of metal lift-off and self-assembled monolayers. Rigorous coupled-wave analyses point to an increase in SPR angular response for the immobilization of surface bioreceptors onto areas of the nano-corrugated surface exhibiting high electromagnetic field intensity. Experimental measurements of the immobilization of anti-TNF-α antibody as a model bioreceptor using an imaging-SPR technique show a 3 times increase in angular resonance response from nano-grating surfaces with functionalized mesas compared to a planar surface or to a uniformly functionalized nano-grating surface. Furthermore, results also show an increased detection of TNF-α due to the increased accessibility to the adsorbed bioreceptors on the nano-gratings.

Plasmon enhanced performance of organic solar cells using electrodeposited Ag nanoparticles

To enhance solar harvesting in organic solar cells, uniform-sized metal nanoparticles of ∼13 nm were incorporated to the device via pulse-current electrodeposition, which is a kind of simple and quick solution process that can control the density and size of metal nanoparticles. By incorporating plasmonic Ag nanoparticles on surface modified transparent electrodes, overall power conversion efficiency was increased from 3.05% to 3.69%, mainly resulting from the improved photocurrent density as a result of enhanced absorption of the photoactive conjugate polymer due to the high electromagnetic field strength in the vicinity of the excited surface plasmons.

Multiple Surface Plasmon Resonances and Near-Infrared Field Enhancement of Gold Nanowells

Arrays of Au nanowells (NWs) were fabricated by electron-beam lithography (EBL) and characterized by surface plasmon resonance (SPR) and surface-enhanced Raman scattering (SERS). It is revealed that these Au NW arrays exhibit multiple SP resonances that can be tuned by adjusting the geometrical characteristics of the NWs. SERS activity of Au NWs was confirmed for a range of excitation wavelengths and a number of model compounds including rhodamine 6G (R6G), phthalazine, and single-stranded oligonucleotides. According to numerical simulations based on the discrete dipole approximation (DDA), SERS enhancement originates from high electromagnetic fields (hot spots) localized both inside and outside individual NWs. In addition, far-field intercoupling effects between NWs have been observed experimentally in arrays with subwavelength pitch sizes. We show that the SERS enhancement factors can also be tuned and optimized by adjusting the geometry of NWs.

Electromagnetic fields produced by incubators influence heart rate variability in newborns

Background:Incubators are largely used to preserve preterm and sick babies from postnatal stressors, but their motors produce high electromagnetic fields (EMFs). Newborns are chronically exposed to these EMFs, but no...

Influence of waveguide geometry on scattering loss effects in submicron strip silicon-on-insulator waveguides

Silicon-on-insulator (SOI) optical waveguides with high electromagnetic field confinement suffer from side-wall roughness, which is responsible for strong scattering inducing propagation loss. A theoretical investigation of the influence of geometry in submicron SOI waveguides on the scattering loss due to side-wall roughness is reported. Scattering loss coefficient is derived for both narrow and flat SOI strip waveguides. It is shown that scattering loss coefficient is significantly increased for narrow waveguides compared with flatter ones. These results show that attention has to be paid to waveguide geometry, as scattering effects are the predominant source of optical losses in strip submicron SOI optical waveguides.

Prospects for nuclear physics with lasers

The development of high intensity lasers has opened up new opportunities for nuclear physics studies in extreme conditions which cannot be reached with conventional particle accelerators. A laser is a unique tool to produce plasma and very high fluxes of photon and particle beams in very short duration pulses. Both aspects are of great interest for fundamental nuclear physics studies. In plasma the electron–ions collisions may modify atomic and nuclear level properties. This is of prime importance for the population of isomeric states and the issue of energy storage in nuclei. Nuclear properties in the presence of very high electromagnetic fields, nuclear reaction rates or properties in hot and dense plasmas are new domains of investigation. Our group has launched an experimental program to evaluate the possibilities for such nuclear physics studies at high intensity laser facilities. This program and its first results are presented.

Design of modified electromagnetic main-flux for steel wire rope inspection

This paper presents the design and construction of modified main-flux equipment for wire rope inspection which has advantages over the in-service inspection and indirect axial-flux measurement used by ordinary main-flux and return-flux methods. The equipment can be adjusted high electromagnetic field strength to produce leakage filed from flaws of various large-diameter ropes. Unique coil sensors connected in series were employed and performed well when sensing leakage fields of the radial, axial and tangential directions. In addition, a standalone system has a simple setup for service inspection. Due to the complicated structure of the wire rope, electromagnetic field theory for anisotropic structures with high electromagnetization was used to design the equipment. The characteristics of the leakage field, in terms of localized fault and loss of metallic cross-sectional area, were distinguished mathematically. The sensor orientation to detect leakage fields was also determined. Performance of the system was then verified experimentally and shown good resolution and repeatability. Furthermore, the equipment is sufficiently sensitive to detect a smallest surface flaw of 1×2 mm at 5 mm equipment lift off. The inspection signals were processed and shown locations, levels and deterioration quantities.

Chalcogenide 광섬유를 이용한 호흡측정 센서 개발을 위한 기초 연구

In this study, we have fabricated an infrared optical fiber based sensor which can monitor the respiration of a patient. The design of a chalcogenide optical fiber based sensor is suitable for insertion into a high electro-magnetic field environment because the sensor consists of low cost and compact mid-infrared components such as an infrared light source, a chalcogenide optical fiber and a thermopile sensor. A fiber-optic respiration sensor is capable of detecting carbon dioxide (<TEX>$CO_{2}$</TEX>) in exhalation of a patient using the infrared absorption characteristics of carbon gases. The modulated infrared radiation due to the presence of carbon dioxide is guided to the thermopile sensor via a chalcogenide receiving fiber. It is expected that a mid-infrared fiber-optic respiration sensor which can be developed based on the results of this study would be highly suitable for respiration measurements of a patient during the procedure of an MRI.