High Frequency Electromagnetic Radiation Research Articles

Polymer Nanocomposites Based on Nanosized Substituted Ferrites (NiZn)1-xMnxFe2O4 on the Surface of Carbon Nanotubes for Effective Interaction with High-Frequency EM Radiation.

To create materials that interact effectively with electromagnetic (EM) radiation, new nanosized substituted ferrites (NiZn)1-xMnxFe2O4 (x = 0, 0.5, and 1) anchored on the surface of multi-walled carbon nanotubes (CNTs) have been synthesized. The concentration of CNTs in the (NiZn)1-xMnxFe2O4/CNT system was from 0.05 to 0.07 vol. fractions. The dielectric and magnetic characteristics of both pristine (NiZn)1-xMnxFe2O4 ferrites and (NiZn)1-xMnxFe2O4/CNT composite systems were studied. The introduction of (NiZn)1-xMnxFe2O4/CNT composites into the amorphous epoxy matrix allows to tailor absorbing properties at the high-frequency by effectively shifting the maximum peak values of the absorption and reflection coefficient to a region of lower frequencies (20-30 GHz). The microwave adsorption properties of (NiZn)1-xMnxFe2O4/0.07CNT-ER (x = 0.5) systems showed that the maximum absorption bandwidth with reflection loss below -10 dB is about 11 GHz.

Effects of 2.4 GHz radiofrequency electromagnetic field (RF-EMF) on glioblastoma cells (U -118 MG).

Mobile phones and Wi-Fi are the most commonly used forms of telecommunications. Initiated with the first generation, the mobile telephony is currently in its fifth generation without being screened extensively for any biological effects that it may have on humans or on animals. Some studies indicate that high frequency electromagnetic radiation emitted by mobile phone and Wi-Fi connection can have a negative effect upon human health, and can cause cancer, including brain tumour. The aim of the study was to investigate the influence of 2.4 GHz radiofrequency electromagnetic field (RF-EMF) on the proliferation and morphology of normal (human embryonic kidney cell line Hek-293) and cancer cells (glioblastoma cell line U-118 MG). The cell cultures were incubated in RF-EMF at the frequency of 2.4 GHz, with or without dielectric screen, for 24, 48 and 72h. In order to analyse the influence of the electromagnetic field on cell lines, Cytotoxicity test Cell Counting Kit-8 was performed. To protect cells against emission of the electromagnetic field, a dielectric screen was used. It was found that 2.4 GHz RF electromagnetic field exposure caused a significant decrease in viability of U-118 MG and Hek-293 cells. The impact of the electromagnetic field was strongest in the case of cancer cells, and the decrease in their survival was much greater compared to the healthy (normal) cells of the Hek-293 line. Results of the study indicate that using a radio frequency electromagnetic field (2.4 GHz) has a clearly negative effect on the metabolic activity of glioblastoma cells. RF-EMF has much less impact on reducing the viability of normal cells (Hek -293) than cancer cells.

Modulating Effect of Extremely High-Frequency Low-Intensity Electromagnetic Radiation on Tissue Oxidative Metabolism and Skin Microhemodynamics

We set out to examine the indicators of microhemodynamics and tissue oxidative metabolism in rats after their tenfold exposure to extremely high-frequency low-intensity electromagnetic radiation (EHF EMR). The aim was to elucidate the specifics of skin microcirculation and tissue oxidative metabolism following exposure to tenfold electromagnetic radiation of extremely high frequency. The experiment was carried out on 40 mature male Wistar rats weighing 200–220 g, which were kept in standard vivarium conditions under natural light regimen. The animals were divided into two groups with 20 rats each. The animals in the first group were biological controls and were exposed to false EHF EMR (placebo); the animals in the second group were exposed to mm-exposure in the morning, 10 sessions daily. On the 10th day of EMR exposure, the indicators of skin tissue fluorescence on the tail base were recorded. Tenfold exposure to low-intensity EHF EMR was shown to increase the concentration and intensity of NADH fluorescence, as well as the FAD and redox ratio. This indicates an increased cellular demand for ATP and the predominance of oxidative phosphorylation over other processes, thus demonstrating the activation of the respiratory chain. At the same time, an increase in endothelium-dependent vasodilation, a decrease in peripheral resistance, an increase in blood flow to the nutritive microvascular bed, and an improvement in venular outflow were observed in the microcirculatory bed. The conclusion is made that the modulating effect of EHF EMR is manifested in the rearrangements of correlations. Thus, the coefficient of variation comes to the fore – the final calculated indicator of microcirculation, which has strong negative associations with all indicators of tissue metabolism (FAD, NADH, RR). In addition, the amplitudes of endothelial rhythms associated with periodic releasing of nitric oxide by the endothelium show a strong negative association with FAD.

MARIE 2.0: A Perturbation Matrix Based Patient-Specific MRI Field Simulator.

High static field MR scanners can produce human tissue images of astounding clarity, but rely on high frequency electromagnetic radiation that generates complicated in-tissue field patterns that are patient-specific and potentially harmful. Many such scanners use parallel transmitters to better control field patterns, but then adjust the transmitters based on general guidelines rather than optimizing for the specific patient, mostly because computing patient-specific fields was presumed far too slow. It was recently demonstrated that the combination of fast low-resolution tissue mapping and fast voxel-based field simulation can be used to perform a patient-specific MR safety check in minutes. However, the field simulation required several of those minutes, making it too slow to perform the dozens of simulations that would be needed for patient-specific optimization. In this paper we describe a compressed-perturbation-matrix technique that nearly eliminates the computational cost of including complex coils (or coils and shields) in voxel-based field simulation of tissue, thereby reducing simulation time from minutes to seconds. The approach is demonstrated on a wide variety of head+coil and head+coil+shield configurations, using the implementation in MARIE 2.0, the latest version of the open-source MR field simulator MARIE.

LOFAR Observations of Lightning Initial Breakdown Pulses

AbstractThis paper reports an observational study of lightning initial breakdown pulses (IBPs) using the low‐frequency array radio telescope and a broadband magnetic field sensor. The data show that the overall spatiotemporal evolution of the electrical breakdown causing an IBP is rather complex. During an IBP, spatially and temporally separated bursts of very high frequency (VHF) electromagnetic radiation occur in a volume on the order of 1003 m3, and they are coincident with brief magnetic field pulses, indicating that the location of the active breakdown region can change suddenly. Furthermore, recurrent breakdown activity is observed, especially at the location of the VHF burst. Interpreting each VHF burst as being generated by a corona burst, an IBP pulse appears to start off from an initial corona burst and subsequent corona bursts enhance it. We further suggest that the generation of IBPs likely involves multiple space stems/leaders and connections between them.

Non-Gaussian speed distributions: OMNI multisatellite data and simulations based on two temperature model

The multi-satellite OMNI solar wind speed data are analyzed, and six distinct types of non-Gaussian probability distributions are investigated. These include the three and four peak probability distributions, bell-shaped probability distribution with nipple-like single peak, bimodal, kinky-flat-top, and bump-on-tail speed distributions. It is also found that cumulative probability distributions for these included the shock-like, sudden jumps, and linear trends toward the peak value of one. This work also studies temperature probability distributions for laser-solid coupling, by analyzing the simulation data for the two temperature model. It is very surprising to find that non-Gaussian temperature distributions resulting from laser–solid interaction match with those found in solar wind data. Therefore, it is concluded that high frequency electromagnetic radiation is a valid candidate for shaping non-Gaussian speed distributions in solar wind.

Sensitivity of plants to high frequency electromagnetic radiation: cellular mechanisms and morphological changes

The technological advancement and increased usage of wireless and other communication devices have greatly enhanced the level of radiofrequency electromagnetic field radiation (EMF-r) in the environment. It has resulted in unprecedented increased exposure of living organisms to these radiations. Most of the studies in past have, however, focused on animal systems and comparatively less attention has been paid to plants with studies reporting various, sometimes contradictory effects. This review is an attempt to provide a critical appraisal of the available reports regarding the impacts of these radiations on plant development and the underlying physiological, biochemical, and molecular mechanisms involved. Here, we propose that the main entry point for the biological effects of EMF-r corresponds to an increase in ROS metabolism and cytosolic calcium that leads to various cellular responses including changes in gene expression and/or enzymatic activities, which could ultimately result in immediate cellular alterations or delayed plant growth. This may constitute a new perspective in the interpretation of plant responses to EMF-r exposure. Understanding the impacts of EMF-r and the inherent abilities of plants to cope up with such changes should lead to EMF-r being considered as full-fledged environmental signals that are perceived by the plants and integrated into their development patterns.

Application of nanotechnology in technological processes of animal husbandry in Ukraine

Today, it is becoming more and more obvious that those countries that develop electronics, nanotechnology and biotechnology will have an advantage. The studies carried out have shown that the use of nanotechnology and nanomaterials in animal husbandry currently allows solving a number of acute problems and provides a significant effect. In animal husbandry, it is advisable to use nanotechnology in technological processes, where they provide additional advantages. When forming the microclimate in the premises for keeping animals and poultry, the use of nanotechnology makes it possible to replace the energy-intensive supply and exhaust ventilation system with an energy-saving airconditioning system while ensuring the regulatory parameters of the microclimate: temperature, humidity, gas composition, microbial content, dustiness, air velocity, eliminating odors while maintaining the heat release of animals. Nanoelectrotechnology in the technological processes of poultry farming using high and medium-high frequency electromagnetic radiation allows for: ultraviolet irradiation of hatching eggs and young poultry in order to decontaminate them from pathogens and stimulate perinatal (during incubation) development of young animals (studies have shown that hatchability of chickens increases to 94, and their preservation is up to 99%); disinfection and pasteurization of eggs; division of young poultry by sex. Taking into account the problems of environmental pollution, emissions with an unpleasant smell and gases affecting global warming, existing in animal husbandry, the most effective at present is the use of film-forming solutions of catalytic action. A promising development is the development of environmentally friendly nanotechnology for electroconservation of silage mass of green fodder with an electroactivated preservative instead of expensive organic acids, which require strict safety measures.

Clustering Artificial Atoms Induced by High-Frequency Electromagnetic Radiation in Graphene Monolayers of Multiwalled Carbon Nanotubes

A graphene-charge carrier confinement induced by high-frequency photons and a subsequent clustering of artificial atoms in graphene plane have been studied using electrophysical and Raman-spectroscopy methods. To fabricate the graphene n-p-n junctions, commensurable superlattice structures consisting of multi-walled carbon nanotubes (MWCNTs) have been formed utilizing a Langmuir-Blodgett technique. It has been shown that the p-n graphene junctions are sensitive to graphene lattice-deformation defects only. The levels of graphene defect do not host impurity electrons. One offers a mechanism of graphene monolayer self-repairing after a radiation damage. This mechanism is based on an existence of topologically protected Compton scatterers in graphene plane.

Growth properties and hydrogen yield in green microalga Parachlorella kessleri: Effects of low-intensity electromagnetic irradiation at the frequencies of 51.8 GHz and 53.0 GHz

The current research reports the effects of low-intensity extremely high frequency electromagnetic irradiation (EMI) of 51.8 GHz and 53.0 GHz on green microalga Parachlorella kessleri RA-002 isolated in Armenia. EMI demonstrated different effects on the growth properties of microalgae under various conditions. Under aerobic conditions a positive effect of EMI on the growth rate of P. kessleri and the content of photosynthetic pigments were observed. The data obtained indicates a significant role of O2, since the enhancing effect of EMI was determined only under aerobic conditions. Meanwhile under anaerobic conditions EMI with both frequencies caused inhibition of algal growth and a decrease in the amount of photosynthetic pigments. EMI also inhibited the yield of H2 production in P. kessleri, which was partially restored after 5-day cultivation due to the existence of protective mechanisms in this alga. The results might indicate membrane-bound mechanisms of EMI action on algae, which can be associated with the effects on photosynthetic pigments and membrane-associated enzymes responsible for H2 production. The results are useful for the development of algae biotechnology and the possibility of using EMI as a factor which regulates the production of biomass and biohydrogen by green microalgae.

Morphological and cytophysiological changes in selected lines of normal and cancer human cells under the influence of a radio-frequency electromagnetic field.

Currently, mobile phones and Wi-Fi are the most commonly used forms of telecommunication. The popularity of mobile telecommunications has made it necessary to investigate the problem more comprehensively and cautiously assess the possible risks, because never before in history has such a substantial proportion of the population been exposed to microwaves at comparably high levels. Some studies indicate that the high frequency electromagnetic radiation emitted by mobile phone and Wi-Fi connections can have a negative effect on human health, and can cause cancer. The aim of the study was to investigate the influence of the radiofrquency electromagnetic field (RF-EMF) on the metaboloc activity and morphology of normal human cells (fibroblasts) and cancer cells (prostate cancer cells). The cell cultures (human fibroblasts and prostate cancer cells) were exposed to RF-EMF at the frequency of 2.5 GHz for 24, 48 and 72h. To quantify changes in cell viability, the Cell Counting Kit - 8 was used. It was found that the RF electromagnetic field exposure caused a significant decrease in the viability of fibroblasts, and a significant increase in cancer cells. Morphological analysis did not show significant changes in both cell lines after exposure to RF-EMF. On the basis of the obtained results, the hypothesis can be formulated that a high frequency electromagnetic field can have harmful effects on human cells.

Dielectric Properties of Polymer Composites with Nanocarbon Allotropes

Background:The paper describes the types and electrical properties of polymer nanocomposites containing carbon allotropes.Objective:Direct current conductivity, conduction in percolation systems, conduction mechanisms and factors controlling conductivity and percolation parameters are considered.Method:The dielectric properties of polymer nanocomposites are presented, and experimental methods and methods for analyzing the results have also been described. An analysis of the data on ac electrical conductivity, including the contribution of nanofiller - interfacial polarization is presented. Special consideration is given to the role of nanocarbons as dielectric probes.Results:The microwave properties of polymer nanocomposites, their use to estimate the distribution of nanofiller in the matrix, as well as practical applications for shielding and absorption of electromagnetic radiation have been analyzed.Conclusion:The use of carbon allotropes nanoparticles as fillers with high electrical conductivity provides polymer composites with useful electrical properties, including the ability to absorb highfrequency electromagnetic radiation.

Understanding the Radio Spectrum of Thunderstorm Narrow Bipolar Events

AbstractThis paper reports a study to understand the radio spectrum of thunderstorm narrow bipolar events (NBEs) or compact intracloud discharges, which are powerful sources of high‐frequency (HF) and very high frequency (VHF) electromagnetic radiation. The radio spectra from 10 kHz to about 100 MHz are obtained for three NBEs, including one caused by fast positive breakdown and two by fast negative breakdown. The results indicate that the two polarities of fast breakdown have similar spectra, with a relatively flat spectrum in the HF and VHF band. The ratio of energy spectral densities in the very low frequency and HF bands is (0.9–5) × 105. We develop a statistical modeling approach to investigate if a system of streamers can explain the main features of fast breakdown. Assuming that the current moment peak and charge moment change of individual streamers vary in the ranges of 5–10 A‐m and 5–20 μC‐m, respectively, the modeling results indicate that a system of 107–108 streamers can reproduce the current moment, charge transfer, and radio spectrum of fast breakdown. The rapid current variation on a time scale of nanoseconds required for fast breakdown to produce strong HF/VHF emissions is provided by exponentially accelerating and expanding streamers. Our study therefore supports the hypothesis that fast breakdown is a system of streamers. Finally, suggestions are given regarding future streamer simulations and NBE measurements in order to further develop our understanding of NBEs and lightning initiation.

A Cold-Cathode Microwave and Terahertz Radiation Source: Experimental Realization @10’s GHz and Computational Design @THz

Due to their unique characteristics of instant responses and low-power consumption, vacuum electronic devices based on field emission cold-cathode have potentials for realizing compact and novel high frequency electromagnetic wave radiation sources. Herein, a cold-cathode radiation source operating in the frequency range from gigahertz to terahertz is developed, which is based on frequency multiplication by taking advantage of nonlinearity of field electron emission. The radiation source is realized by introducing a compact structure with two re-entrant cavity resonators. Based on such a structure, radiation sources of frequencies at 12.10 GHz and 0.1 THz were, respectively, designed and simulated numerically. Based on the simulation results, the 12.10-GHz radiation source using carbon nanotubes cold-cathode was fabricated and tested experimentally. The results showed that an electromagnetic wave output at 12.10 GHz with power of $98~\mu \text{W}$ can be achieved upon excitation by a 6.05 GHz input signal with power of 1.05 mW. Our study provides an approach for microwave and terahertz wave generation.

A Series DC Arc Fault Detection Method Based on Steady Pattern of High-Frequency Electromagnetic Radiation

Due to detection difficulties, dc arc faults are one of the most dangerous risks in dc power systems. Most traditional studies are based on arc current, which may change during normal operation and cause unwanted trips. Another problem with the traditional methods is that the detection threshold may need to be adjusted for different photovoltaic (PV) systems; otherwise, it will cause malfunctions. To solve the aforementioned problems, a series arc fault detection method based on steady patterns of the frequency domain is proposed. The proposed method utilizes the electromagnetic radiation (EMR) emitted by an arc as a testing basis, avoiding the occurrence of unwanted trips. Patterns such as the structural similarity index (SSIM) and 6-dB bandwidth bins (6-dB BWBs) are calculated to extract the similarity of the steady-burning arc spectra. The experimental verification shows that the proposed steady-pattern-based method can accurately identify arc faults in different dc power systems, discriminate arc faults from normal operations, effectively avoid the occurrence of malfunctions, and can be used as a supplementary technique to traditional methods.

Application of Extremely High Frequency Electromagnetic Radiation in the Rehabilitation of Patients with Oncologic Pathology in the Conditions of a Palliative Care Unit

Objective : to estimate the efficiency of the application of extremely high frequency electromagnetic radiation in patients with oncologic pathology of II, III and IV clinical groups undergoing rehabilitation in the conditions of a palliative care unit at different stages of the development of the disease regardless of the stage of the treatment. Material and methods. The examination included 30 patients diagnosed with oncologic pathology - 13 (43 %) women and 17 (57 %) men. They were divided into 2 groups. The main group comprised 15 people aged 45-79 who were undergoing a rehabilitation course of ten 10-minute sessions of extremely high frequency electromagnetic radiation of millimetric wave band. The study was conducted with the help of the device «Pramen M14T-Z» with a frequency of operating radiation of 42.194 ± 0.015 GHz (wavelength of 7.1 mm). The control group included 15 patients at the age of 34-84. The efficiency of the therapy was estimated by means of the standard questionnaires: the Rivermead Mobility Index (F. M. Collen of 1991), Beck Scale, Wakefield Self-Assessment of Depression Inventory, Hamilton Depression Rating Scale (HAM - D), DN4 and also the assessment of the general blood test before and after the treatment. Results. All the patients who had completed the rehabilitation course in the conditions of the palliative care unit with the application of extremely high frequency electromagnetic radiation of millimetric wave band (Shan Zhong point of VC.17) revealed a decrease in the neuropathic component of pain. Other positive clinical changes of varying degree were observed in both the groups. Conclusion. The application of extremely high frequency electromagnetic radiation is a perspective way of treatment in the complex rehabilitation of patients with oncologic pathology in the conditions of the palliative care unit.

Fatty Acid Content and Tumor Growth Changes in Mice After Exposure to Extremely High-Frequency Electromagnetic Radiation and Consumption of N-3 Fatty Acids

The topical problem is to find new, more effective and safe treatments for cancer. The purpose of the present work was to study the combined effects of low-intensity extremely high-frequency electromagnetic radiation (EHF EMR) and consumption of n-3 polyunsaturated fatty acids (PUFAs) on tumor growth and the content of FAs in the thymus and tumor tissue in mice. Fatty acid composition was determined using gas chromatography. Exposure of tumor-bearing mice with solid Ehrlich carcinoma to EHF EMR with effective parameters (42.2 GHz, 0.1 mW/cm2, 20 min daily for 5 consecutive days beginning on the first day after the tumor inoculation) led to delaying the tumor growth and restored the content of almost all FAs in thymic tissue to the level of intact animals. Animal intake of the preparation enriched with n-3 PUFAs increased the content of n-3 PUFAs in thymic tissue significantly, but did not affect the tumor growth, even in combination with EHF EMR exposure. Combined action of EHF EMR exposure and n-3 preparation promoted recovery of thymus weight in tumor-bearing animals. The data obtained assume a complex interaction between the immune system and the tumor, and the important role of FAs in the regulation of this interaction.

High-frequency electromagnetic radiation affecting moving conductive screens

Protection of on board electronic devises subjected to high-frequency electromagnetic emission is a crucial problem of Space flight safety. The present paper contains the results of theoretical investigation of the effects of high frequency electromagnetic radiation on a moving conductive screen. Methods are developed and results are presented aimed at evaluating conductive screen protective properties depending on thermophysical and electromagnetic properties of material, radiation intensity and frequency, as well as relative velocity of the radiation source and the target.

Development of a standoff terahertz imaging system for concealed weapon detection

AbstractIn this article, terahertz imaging system based on a single‐channel 360 GHz transceiver front‐end and optical‐machine scanning platform, is studied. The transmitting antenna is irradiated by a wide beam of a small aperture antenna to reduce the “angular glint” effect caused by high frequency electromagnetic radiation. The receiving antenna is of a large aperture to ensure high resolution. Beam scanning is achieved through a fast conical scanning method using a total reflector to achieve fast real‐time imaging.

Intracellular regeneration of adrenocorticocytes in response to the prophylactic application of low-intensity electromagnetic radiation under the conditions of radiation (an experimental study)

Adaptation of the organism to the action of certain damaging factors, including radiation, is closely related to the state of the hypothalamic-pituitary-adrenal system. The important role in its activities is played by adrenocorticocytes (ACC) - the cells of the fascicular zone of the adrenal cortex. The disturbance of the structure and function of these cells can significantly impair and limit the development of the adaptive reactions in the body. One of the most promising ways to prevent the post-radiation changes in adrenocorticocytes consists of the application of the non-pharmacological therapeutic factors, such as low-intensity electromagnetic radiation (EMR) of ultra high frequency ( UHF) and the low-frequency (LF) magnetic field (MF) of low intensity (LI) after the exposition of the cells to the action of radiation. The objective of the present study was to identify the ultrastructural regenerative - adaptive changes in ACC of the fascicular zone of the adrenal gland in response to the primary preventive action of ultra high frequency EMR, microwave oven, and low-intensity MF after the exposition of the cells to the action of radiation. The investigations were carried using the outbred male rats (180-200 gr body weight). The experimental animals were allocated to four groups two of which had been preliminarily treated by the application of ultra high frequency EMR and low-intensity MF and were thereafter exposed to radiation. The animals of the third group were exposed to radiation alone without the treatment with the therapeutic physical factors and served as controls whereas the animals of the fourth group underwent no treatment whatever and were regarded as intact. Transmission electron microscopy was used to count light and dark adrenocorticocytes of the fascicular zone. The morphometric analysis of mitochondria included the determination of their number, the average and the total area per standard cell area, and the number of cristae per average area of mitochondria). In addition, the analysis of the lipid content and protein-synthesizing organelles was performed. The study has demonstrated that the primary prophylactic application of ultra high frequency EMR and the low-frequency MF caused stimulation of the cellular and intracellular regenerative-adaptive reactions and increased the resistance of the ultrastructure of ACC in the fascicular zone of the adrenal glands to the action of radiation. These changes were most pronounced in response to the application of ultra high frequency EMR. The resulting structural-adaptive rearrangements of the organelles (the enlargement of mitochondria with the simultaneous increase in the number of cristae, hyperplasia of ribosomes and smooth endoplasmic reticulum, preservation of membranes) were largely due to antioxidative and membrane-stabilizing effects of low-intensity electromagnetic radiation of ultra high frequency and were directly related to the formation of the mechanisms of ACC radioprotection. The Increased regenerative-adaptive potential of these cells prevented the development of the dystrophic processes and protected the adrenocorticocytes from aggressive radiation. The results of the present study suggests the necessity of the further studies on the action of the non-pharmacological therapeutic factors, especially low-intensity electromagnetic radiation (EMR) of ultra high frequency and the low-frequency magnetic field of low intensity as the tools for the prevention of post-radiation changes in the adrenocorticocytes of the fascicular zone of the adrenal cortex exposed to the action of radiation.