High Frequency Electromagnetic Field Research Articles

Protective and damaging role of electromagnetic influences on biomembranes

The paper presents the results of studies of the effect of an alternating low-power electromagnetic field and light irradiation with monochromatic light from a laser source on the state of biological membranes. It was shown that the effect of these factors on the erythrocyte membrane causes a different effect andaffects its resistance differently, which is reflected in the change in the erythrogram of acid hemolysis in the experiment. It has been established that the action of an ultrahigh-frequency electromagnetic field leads to a decrease in the resistance of erythrocytes and an increase in the rate of lysis of red cells. Laserirradiation with a low-power helium-neon laser at low exposure increases the resistance of red blood cells to acid hemolysis. Increasing exposure reduces the effect noted. With simultaneous processing of blood samples by UHF (ultra high frequency electromagnetic fields) source and laser light, a significant decreasein the negative effect of the UHF field on the resistance of biomembranes is noted. Possible mechanisms of marked biological effects are discussed.

Effects of High-Frequency Electromagnetic Field on Ghrelin`S Quantitative Changes and Animal Memory

Ghrelin is one of the major ways of improving memory, which is approved by different amino acids ratio. However, reducing the concentration of Ghrelin helps to prevent the implementation of generated and stiffened nutritional act. The processes of stimulation cause various improvement of expressed behavior on positive stimulus. This is based on the type of overpass labyrinth for improving the reflexive behavior to two feeding test. These facts approve that the processes which was developed as a result of Ghrelin`s and EMF action and the central mechanisms of animals behavioral reaction on positive stimulus were connected to each other by morphofunctional and neurochemical organization.

A fast pothole repair method using asphalt tiles and induction heating

In this paper, a new method to repair potholes in asphalt roads is presented. It consists of an asphalt mixture tile with a bottom bonding layer made of bitumen, and steel fibres. To use this technology, potholes have to be first cleaned, second filled with an asphalt tile and third, exposed to high frequency electromagnetic fields to heat the fibres up and melt the bitumen in the bonding layer. This article assess the bonding properties of tiles built with bonding layers of various thicknesses and amounts and distributions of fibres. Furthermore, the effect of moisture on the bonding properties of asphalt tiles has been examined and the functionality of the tiles observed using wheel track tests. It has been concluded that asphalt tiles are a suitable method to repair potholes, and the durability of the repaired surface is comparable to that of a newly built road.

Electromagnetic Shielding Material Effects on the Ordnance Store Protection

A kind of entity modeling and simulation method of the electromagnetic shielding research is put forward based on the FEKO software for ammunition warehouse wall with different properties and thickness of protective coatings. Simulation shows that it can significantly improve the high frequency electromagnetic field shielding effectiveness for adding the carbon powder, steel fiber and other conductive materials in the concrete, but not much effect on low frequency electromagnetic field. Metal coating with low electrical conductivity of the composite coating has higher shielding effectiveness with increase of the external electromagnetic field frequency and intensity, it has high shielding effectiveness for metal coating with low conductivity of the composite coating. The shielding effectiveness is gradually reduced for seam hole, but at 0.7 ~ 0.8 GHz resonance occurs, the shielding effectiveness of the worst, the shielding effectiveness on the Ordnance depot has a effect for reinforced steel bar mesh size and network mode, and the diameter of hole seam shape and size, it provides technical support and method for the ammunition electromagnetic protection etc.

Analyzing Exposures to Electromagnetic Fields in an Intensive Care Unit.

In this study, we conducted a numerical analysis of exposure to electromagnetic fields (EMFs) in a hospital's intensive care unit that is one of the most crucial one in terms of hazardous areas among all service units. This is a new study for measuring exposure to EMFs in an intensive care unit as well as other healthcare services in Turkey. We measured the EMFs in the intensive care unit with a SRM-3006 (selective radiation metre), which was used for measurement of the absolute and the limit values of high frequency EMFs. The measurement points were chosen to represent the highest levels of exposure to which a person might be subjected. We obtained a dataset that included 5929 observations, with 96 extreme values, through measuring the magnetic field in terms of V/m. The measurements show the frequency varies from 47 MHz to 2.5 GHz as 17 frequency ranges at the measurement point as well. According to these findings, the referenced maximum safety limit was not exceeded. However, it was also found that mobile telecommunication was the most critical cause of magnetic fields. Further studies need to be performed with different frequency antennas to assess the EMFs in intensive care units.

Developing Antitumor Magnetic Hyperthermia: Principles, Materials and Devices.

Methods of local or loco-regional anticancer treatment are of the utmost importance because the therapeutic 'power' is applied directly to the disease site. Consequently, general toxicity is minimized. Hyperthermia, that is, a sustained increase of intratumoral temperature up to 45oC, has been investigated as a perspective treatment modality alone and/or in combination with ionizing radiation or chemotherapy. Still, the surrounding tissues can be damaged by the external heat. Development of new materials and devices gave rise to methods of inducing hyperthermia by a high frequency magnetic or electromagnetic field applied to the tumor with exogenous nanosized particles captured within it. The idea of this approach is the release of local heat in the vicinity of the magnetic nanoparticle in a time-varying magnetic field due to transfer of external magnetic field energy into the heat. Therefore, tumor cells are heated whereas the peritumoral non-malignant tissues are spared. This review analyzes recent advances in understanding physical principles that underlie magnetic hyperthermia as well as novel approaches to obtain nanoparticles with optimized physico-chemical, toxicological and tumoricidal properties. Special focus is made on the construction of devices for therapeutic purposes. The review covers recent patents and general literature sources regarding magnetic hyperthermia, the developing approach to treat otherwise intractable malignancies. </p><p&gt.

Combined effects of diesel exhaust nanoparticles and high frequency electromagnetic fields on the permeability of an in vitro blood-brain barrier model

Air pollution-exposure is associated with detrimental outcomes in the central nervous system (CNS) such as cerebrovascular disorders, including stroke, and neurodegenerative diseases. While the mechanisms of these CNS-related outcomes involved have not been fully elucidated, exposure to traffic-generated air pollutants has been associated with altered blood brain barrier (BBB) integrity and permeability. The current study investigated whether inhalation exposure to mixed vehicle emissions (MVE) alters cerebral microvascular integrity in healthy 3 mo old C57BL/6 mice, as well as whether exposure-mediated effects were exacerbated by a high-fat (HF) vs. low-fat (LF) diet. Mice on each diet were randomly assigned to be exposed to either filtered air (FA) or MVE [100 PM/m3 vehicle emissions mixture: 30 µg PM/m3 gasoline engine + 70 µg PM/m3 diesel engine emissions; median size ~ 60 nm; particle mass size distribution median of ~ 1 µm (range: < 0.5–20 µm)] for 6 h/d, 7d/wk, for 30d. Using sodium fluorescein as a tracer, we observed a significant increase in BBB permeability in both HF + MVE exposed and HF + FA animals, compared to LF + FA controls. Exposure to HF + MVE also led to a significant increase plasma ox-LDL and ox-LDL scavenger receptors (LOX-1 and CD-36) expression in the cerebral vasculature. Histological analysis revealed decreased expression of TJ protein, claudin-5, associated with increased matrix metalloproteinase (MMP)−9 activity and oxidative stress in the cerebral vasculature of HF + MVE mice, compared to LF + MVE. Such findings indicate that inhalation exposure to traffic-generated pollutants, coupled with a HF diet, results in altered BBB integrity and increased ox-LDL signaling in the cerebral vasculature in a wildtype animal model.

On board electronic devices safety subject to high frequency electromagnetic radiation effects

Spacecraft on board electronic devices are subjected to the effects of Space environment, in particular, electromagnetic radiation. The weight limitations for spacecraft pose an important material and structures problem: developing effective protection for on board electronic devices from high frequency electromagnetic radiation. In the present paper the problem of the effect of external high frequency electromagnetic field on electronic devices shielding located on orbital platforms is investigated theoretically. It is demonstrated that the characteristic time for the unsteady stage of the process is negligibly small as compared with characteristic time of electromagnetic field diffusion into a conductor for the studied range of governing parameters. A system of governing material parameters is distinguished, which contribute to protecting electronic devices from induced electrical currents.

High-Frequency Electromagnetic Field Coupling to a Long, Finite Wire With Vertical Risers Above Ground

The main goal of this paper is the analytic approximation of the singularity expansion method poles of a long finite wire with vertical risers above a perfectly conducting ground. For wavelengths in the same order of magnitude or smaller than the height of the wire above the ground, the classical transmission-line theory is not valid. Therefore, an asymptotic approach is used to approximate the current on the thin wire, which is expressed in terms of current reflection and scattering coefficients. The perturbation theory is used for their analytic calculation. The complex current is analytically approximated and compared to a numerical simulation for illustration purposes. A very good agreement between the analytic approximations and the numerical ones from literature and simulations is observed.

Effects of electromagnetic field exposure on conduction and concentration of voltage gated calcium channels: A Brownian dynamics study

A three-dimensional Brownian Dynamics (BD) in combination with electrostatic calculations is employed to specifically study the effects of radiation of high frequency electromagnetic fields on the conduction and concentration profile of calcium ions inside the voltage-gated calcium channels. The electrostatic calculations are performed using COMSOL Multiphysics by considering dielectric interfaces effectively. The simulations are performed for different frequencies and intensities. The simulation results show the variations of conductance, average number of ions and the concentration profiles of ions inside the channels in response to high frequency radiation. The ionic current inside the channel increases in response to high frequency electromagnetic field radiation, and the concentration profiles show that the residency of ions in the channel decreases accordingly.

EFFECTS OF LOW FREQUENCY ELECTROMAGNETIC FIELD ON THE HUMAN BODY

International standardization institutions, which play an important role in assessing the effects of the field and determining the need to take protective measures for the human factor, developed safety standards on human exposure to electromagnetic field, differentiated for electric and magnetic fields of low frequency ( near fields), as well as to electromagnetic radiation fields (far fields). Until recently, many studies has shown that the main harmful effect on the human body was produced by high frequency electromagnetic field, but in recent years, more and more information also reveals that the serious damage can be caused by low frequency electric and magnetic fields. These low-frequency electromagnetic fields interact with human tissue causing harmful effects, the degree of destruction depending on factors such as: intensity, frequency, energy field level and duration of exposure

A numerical study of iterative substructuring method for finite element analysis of high frequency electromagnetic fields

This paper describes iterative methods for the high frequency electromagnetic analysis using the finite element method of Maxwell equations including displacement current. The conjugate orthogonal conjugate gradient method has been widely used to solve a complex symmetric system. However, the conventional method suffers from oscillating convergence histories in large-scale analysis. In this paper, to solve large-scale complex symmetric systems arising from the formulation of the E method, an iterative substructuring method like the minimal residual method is presented, and the performance of the convergence of the method is evaluated by numerical results. As the result, the proposed method shows a stable convergence behavior and a fast convergence rate compared to other iterative methods.

Bioactive Compounds Diffusion from Grapes to Wines under High Frequency Electromagnetic Field Treatments

In this paper, grapes were processed by using high frequency electromagnetic field in order to obtain a high quality wine in terms of bioactive compounds content with antioxidant activity. The experimental setup comprise an applicator with adjustable power between 100-1000 W, software assisted, in order to process three varieties of grapes (Muscat Ottonel, Merlot, Pinot Noir), that were harvested in 2014 in the Crişana-Sântimreu vineyard. The total polyphenol compounds were measured using the Folin-Ciocalteu spectrophotometric method, and the antioxidant capacity was determined by the FRAP method. The results have shown that the use of high frequency electromagnetic field in grape processing leads to the diffusion of the bioactive compounds with antioxidant activity in the final product. In the same time, it is also an effective method in terms of energy consumption.

Millimeter waves or extremely high frequency electromagnetic fields in the environment: what are their effects on bacteria?

Millimeter waves (MMW) or electromagnetic fields of extremely high frequencies at low intensity is a new environmental factor, the level of which is increased as technology advance. It is of interest that bacteria and other cells might communicate with each other by electromagnetic field of sub-extremely high frequency range. These MMW affected Escherichia coli and many other bacteria, mainly depressing their growth and changing properties and activity. These effects were non-thermal and depended on different factors. The significant cellular targets for MMW effects could be water, cell plasma membrane, and genome. The model for the MMW interaction with bacteria is suggested; a role of the membrane-associated proton FOF1-ATPase, key enzyme of bioenergetic relevance, is proposed. The consequences of MMW interaction with bacteria are the changes in their sensitivity to different biologically active chemicals, including antibiotics. Novel data on MMW effects on bacteria and their sensitivity to different antibiotics are presented and discussed; the combined action of MMW and antibiotics resulted with more strong effects. These effects are of significance for understanding changed metabolic pathways and distinguish role of bacteria in environment; they might be leading to antibiotic resistance in bacteria. The effects might have applications in the development of technique, therapeutic practices, and food protection technology.

STUDY ON THE DEPENDENCY OF STEADY STATE RESPONSE ON THE RATIO OF LARMOR AND RABI FREQUENCY FOR ESR USING MATLAB

In this project we simulate with very high accuracy specially to study the dependency of the steady state power and dispersion output on the ratio (r) between Larmor and Rabi frequency for the electron spin resonance experiment by the matlab software (version 7.9.0.529(R2009b)). Where the sample material (DPPH) has been kept in a strong static magnetic field (B0) and in orthogonal direction a high frequency electromagnetic field (B1(t)) has been applied. We divide our simulation into two parts. In the first part we ignore the terms and observe the dependency of the power maximum on the amplitude of the oscillating e.m. field B1 (for fixed (ωL) Larmor frequency) and on ωL (for fixed B1). Also observe a clear shift (Δω) of the power maxima (Pmax) from ωL. In our second part we consider the term and the ratio (r) between Larmor and Rabi frequency and observe the shift (Δω) of the power maxima (Pmax) from ωL and change in peak to peak line width (ΔBPP) with B1 both depends upon the ratio r. we consider various range of r ([0.83,5], [16,100], [88.3,500], [1000,2000], [833.3,5000]) and observe these dependency. We observe as the ratio of r increases the output i.e. shift (Δω) and the change in ΔBPP with B1 decreases and converges to the case of neglecting terms. We also observe the shift (Δω) follows some non linear relationship with B1.

MODIFIED GO SOLUTIONS FOR THE HIGH FREQUENCY REFLECTED WAVE IN THE FOCAL REGION OF A 3D ELLIPTICAL REFLECTOR PLACED IN ISOTROPIC CHIRAL MEDIUM

High frequency electromagnetic (EM) fields in the focal region of a 3D elliptical reflector placed in a homogeneous and reciprocal chiral background have been analyzed using geometrical optics (GO) approximation and Maslov's method. The GO solutions becomes invalid at the focal region of a 3D elliptical reflector due to unreal singularities. Therefore, an asymptotic method based on Maslov's theory has been applied to derive high frequency EM fields, which is also valid at the focal points. Moreover, the effect of chirality parameter of the background medium on the position of focal points for both Left circularly polarized wave (LCP) and right circularly polarized (RCP) wave are described by plotting the derived expressions numerically using MATLAB.

Effects of extremely low frequency pulsed magnetic fields on diabetic nephropathy in streptozotocin-treated rats.

BackgroundExtremely low frequency pulsed magnetic fields (ELFPMF) have been shown to induce Faraday currents and measurable effects on biological systems. A kind of very high frequency electromagnetic field was reported that it improved the symptoms of diabetic nephropathy (DN) which is a major complication of diabetes. However, few studies have examined the effects of ELFPMF DN at the present. The present study was designed to investigate the effects of ELFPMF on DN in streptozotocin (STZ)–induced type 1 diabetic rats.MethodsAdult male SD rats were randomly divided into three weight-matched groups: Control (non-diabetic rats without DN), DN + ELFPMF (diabetic rats with DN exposed to ELFPMF, 8 h/days, 6 weeks) and DN (diabetic rats with DN exposed to sham ELFPMF). Renal morphology was examined by light and electron microscopy, vascular endothelial growth factor (VEGF)-A and connective tissue growth factor (CTGF) were measured by enzyme linked immune sorbent assay.ResultsAfter 6 weeks’ ELFPMF exposure, alterations of hyperglycemia and weight loss in STZ-treated rats with DN were not found, while both positive and negative effects of ELFPMF on the development of DN in diabetic rats were observed. The positive one was that ELFPMF exposure attenuated the pathological alterations in renal structure observed in STZ-treated rats with DN, which were demonstrated by slighter glomerular and tubule-interstitial lesions examined by light microscopy and slighter damage to glomerular basement membrane and podocyte foot processes examined by electron microscopy. And then, the negative one was that ELFPMF stimulation statistically significantly decreased renal expression of VEGF-A and statistically significantly increased renal expression of CTGF in diabetic rats with DN, which might partially aggravate the symptoms of DN.ConclusionBoth positive and negative effects of ELFPMF on the development of DN in diabetic rats were observed. The positive effect induced by ELFPMF might play a dominant role in the procession of DN in diabetic rats, and it is suggested that the positive effect should be derived from the correction of pathogenic diabetes-induced mediators.

Acoustic wave energy absorption and distributed heat sources upon an acoustic impact on media

The absorption of acoustic wave energy by media and the occurrence, in that connection, of distributed heat sources are investigated. The distribution of the totality of heat sources for the case of impact on an oil bed by high frequency electromagnetic and acoustic fields is considered. Comparative graphic charts of distribution of the heat sources produced by these fields separately and in total are provided, and the results obtained are analyzed.

Modelling, Simulation and Experimental Analysis of a Metal-Polymer Hybrid Fibre Based Microstrip Resonator for High Frequency Characterisation

Conductive multifilament fibres are the fundamental core for wearable technology in the biomedical engineering fields, as conductors in sensors or in bio-sensing textiles for healthcare. This contribution presents a model, simulation and the experimental analysis of a metal-polymer hybrid fibre based microstrip resonator for high frequency characterisation. The high frequency electromagnetic field simulation (HFSS) by ANSYS® is used for the modelling and finite element based simulation. It follows the design and manufacturing of the metal-polymer hybrid fibre based microstrip resonator for analysis of the scattering parameter measurements and the quality factors to 10GHz with a vector network analyser (VNA) by Rohde & Schwarz®. Simulations and analysis also compare solid matter wire with the metal-polymer hybrid fibre.

Stress Signaling Responses in Plants.

Stress Signaling Responses in Plants.