Bioelectromagnetics最新文献

Energy-based devices are used to improve features of appearance for aesthetic reasons while avoiding more invasive methods. Examples of treatment targets are the reduction of wrinkles, sagging, unwanted skin lesions, body hair and excess fatty tissue, and the enhancement of muscle tissue. One treatment modality is the use of electromagnetic fields (EMF, 0‒300 GHz). The present work aims to give an up-to-date survey of cosmetic applications of EMF for professional use with an assessment of client and worker exposure and possible adverse effects. A systematic search was conducted for peer-reviewed articles (2007–2022), patents, premarket notifications, manufacturer data, and adverse effects reports. Five categories of cosmetic EMF device with increasing frequency were identified: sinusoid low frequency magnetic fields for lipolysis; pulsed low frequency magnetic fields for skin rejuvenation; pulsed low frequency magnetic fields for muscle building; radiofrequency EMF for lipolysis or skin rejuvenation; microwaves for hair removal or hyperhidrosis. In the vicinity of the last four device categories, there is a potential for exceeding the occupational exposure limits in the European Union EMF Directive, which could lead to nerve or muscle stimulation, burns or overheating. There are also potential hazards for clients or workers wearing active or passive medical devices. The severity of reported adverse effects increases with EMF frequency.

In Greece, 5G New Radio (NR) has started launching in the end of 2020, at the 3400–3800 MHz (FR1) frequency band. Focusing on 117 Base Stations (BSs) which were already equipped with 5G NR antennas, in situ broadband and frequency selective measurements have been conducted at minimum three points of interest, at adjacent rooftops (when accessible). The points have been selected according to the sweeping method and the electric field strength (E) value has been stored on the selected worst-case scenario point. Spectrum analysis was conducted in the FR1, for the allocated spectrum that corresponds to each mobile communication provider, in order to get preliminary results concerning the contribution of the 5G NR emissions in the general public exposure levels. The vast majority of the in situ measurements has been conducted in urban environments from the beginning of 2021 until the mid of 2022, since in Greece 5G NR services launching started from the big cities. Additionally, a 5G NR BS, installed in a suburban environment (in the city of Kalamata) is thoroughly investigated during its pilot and regular operation, based on broadband and frequency selective measurements data derived by the National Observatory of Electromagnetic Fields (NOEF) monitoring sensor network. In situ measurement data within the 5G NR frequency range are verified via the NOEF's output. The 5G NR contribution to the total E-field levels is assessed in time, from pilot to regular operation of the BS. In all cases, compliance with the reference levels for general public exposure is affirmed.

In recent years exposure of living beings to radiofrequency radiation (RFR) emitted from wireless equipment has increased. In this study, we investigated the effects of 3.5-GHz RFR on hormones that regulate energy metabolism in the body. Twenty-eight rats were divided into four groups: healthy sham (n = 7), healthy RFR (n = 7), diabetic sham (n = 7), and diabetic RFR (n = 7). Over a month, each group spent 2 h/day in a Plexiglas carousel. The rats in the experimental group were exposed to RFR, but the sham groups were not. At the end of the experiment, blood and adipose tissues were collected from euthanized rats. Total antioxidant, total oxidant, hydrogen peroxide, ghrelin, nesfatin-1, and irisin were determined. Insulin expression in pancreatic tissues was examined by immunohistochemical analysis. Whole body specific absorption rate was 37 mW/kg. For the parameters analyzed in blood and fat, the estimated effect size varied within the ranges of 0.215–0.929 and 0.503–0.839, respectively. The blood and adipose nesfatin-1 (p = 0.002), blood and pancreatic insulin are decreased, (p = 0.001), gherelin (p = 0.020), irisin (p = 0.020), and blood glucose (p = 0.040) are increased in healthy and diabetic rats exposed to RFR. While nesfatin-1 are negatively correlated with oxidative stress, hyperglycemia and insulin, ghrelin and irisin are positively correlated with oxidative stress and hyperglycemia. Thus, RFR may have deleterious effects on energy metabolism, particularly in the presence of diabetes.

In recent years, an increasing number of studies have discussed the mechanisms of vestibular activation in strong magnetic field settings such as occur in a magnetic resonance imaging scanner environment. Amid the different hypotheses, the Lorentz force explanation currently stands out as the most plausible mechanism, as evidenced by activation of the vestibulo-ocular reflex. Other hypotheses have largely been discarded. Nonetheless, both human data and computational modeling suggest that electromagnetic induction could be a valid mechanism which may coexist alongside the Lorentz force. To further investigate the induction hypothesis, we provide, herein, a first of its kind dosimetric analysis to estimate the induced electric fields at the vestibular system and compare them with what galvanic vestibular stimulation would generate. We found that electric fields strengths from induction match galvanic vestibular stimulation strengths generating vestibular responses. This review examines the evidence in support of electromagnetic induction of vestibular responses, and whether movement-induced time-varying magnetic fields should be further considered and investigated.

A crucial aspect of IARC's evaluation of the relative carcinogenicity of agents is the communication of its conclusions. The present paper addressed the experimental risk perception literature pertaining to IARC's radiofrequency electromagnetic field evaluation communication, and derived specific recommendations for improving it.

Whether human cells are impacted by environmental electromagnetic fields (EMF) is still a matter of debate. With the deployment of the fifth generation (5G) of mobile communication technologies, the carrier frequency is increasing and the human skin becomes the main biological target. Here, we evaluated the impact of 5G-modulated 3.5 GHz radiofrequency (RF) EMF on mitochondrial stress in human fibroblasts and keratinocytes that were exposed for 24 h at specific absorption rate of 0.25, 1, and 4 W/kg. We assessed cell viability, mitochondrial reactive oxygen species (ROS) production, and membrane polarization. Knowing that human skin is the main target of environmental ultraviolet (UV), using the same read-out, we investigated whether subsequent exposure to 5G signal could alter the capacity of UV-B to damage skin cells. We found a statistically significant reduction in mitochondrial ROS concentration in fibroblasts exposed to 5G signal at 1 W/kg. On the contrary, the RF exposure slightly but statistically significantly enhanced the effects of UV-B radiation specifically in keratinocytes at 0.25 and 1 W/kg. No effect was found on mitochondrial membrane potential or apoptosis in any cell types or exposure conditions suggesting that the type and amplitude of the observed effects are very punctual.

The blood-brain barrier (BBB) is the main obstacle to hydrophilic and large molecules to enter the brain, maintaining the stability of the central nervous system (CNS). But many environmental factors may affect the permeability and structure of the BBB. Electromagnetic pulses (EMP) irradiation has been proven to enhance the permeability of the BBB, but the specific mechanism is still unclear. To explore the potential mechanism of EMP-induced BBB opening, this study investigated the permeability, fine structure and the proteins expression of the tight junction (TJ) of the BBB in the rats exposed to EMP. Using the leakage of fluorescein isothiocyanate-labeled dextran with different molecular mass under different field intensity of EMP exposure, we found that the tracer passing through the BBB is size-dependent in the rat exposed to EMP as field intensity increased. Transmission electron microscopy showed TJ of the endothelial cells in the EMP-exposed group was open, compared with the sham-irradiated group. But the levels of TJ proteins including ZO-1, claudin-5, or occludin were not changed as indicated by western blot. These data suggest that EMP induce BBB opening in a field intensity-dependent manner and probably through dysfunction of TJ proteins instead of their expression. Our findings increase the understanding of the mechanism for EMP working on the brain and are helpful for CNS protection against EMP.

For the study of biological effects of direct current (DC) and extremely low frequency (ELF) electric fields, we have quantitatively analyzed red blood cell (RBC) movement in whole blood. Considering the inhomogeneous distribution of electric fields in vivo, five different electric field distributions were generated under a microscope. For theoretical analyses, we assumed electrophoresis and dielectrophoresis as basic motive forces and obtained the spatial distribution of blood cell velocity. The RBC velocity was measured using video image analysis. The spatial dependence of the velocity showed good agreement with that predicted by theoretical analysis. This result suggests the validity of the theoretical model based on electrophoresis and dielectrophoresis for the study of ELF electric field exposure to inhomogeneous animal and human bodies. Next, using the same measurement system, we attempted to find the electric field strength at which these effects occur. The threshold values were found to be 0.40 and 1.6 kV/m, respectively, for DC and AC electric field exposures. Furthermore, we investigated the reproducibility of the field effects in more realistic conditions of human exposure. The RBCs in microchannels were exposed to the electric field generated in capacitive coupling using electrodes separated by an air gap. Even in the new condition, similar effects were observed, which also verified the validity of the analysis described above. These results will provide useful information for the safety assessment of field exposure and for the future biomedical applications of electric fields to manipulate RBCs in vivo.

Band 3 protein and glycophorin C are the two major integral proteins of the lipid membrane of human red blood cells (RBCs). They are attached from below to a network of elastic filamentous spectrin, the third major RBC membrane protein. The binding properties of the attachments to spectrin affect the shape and deformability of RBCs. We addressed band 3 and glycophorin C attachments to spectrin by measuring the strength of two recently discovered radiofrequency dielectric relaxations, β_sp (1.4 MHz) and γ1_sp (9 MHz), that are observable as changes in the complex admittance of RBCs in medium. In medium at pH 5.2, and also in media with protic substances (formamide, methylformamide, or urea), the β_sp relaxation became inhibited that is attributable to detachment of glycophorin C from spectrin. In medium at pH 9.2, we observed inhibition of γ1_sp relaxation attributable to detachment of band 3 from spectrin, as also was seen in media with aprotic substances difluoropyridine, dimethylsolfoxide, dimethylformamide, acetone, sodium tetrakis(4-fluorophenyl)borate), chlorpromazine, thioridazine and trifluopiperazine. The viscogenic cosolvents (glycerol, ethylene glycol, or i-erythritol) inhibited both the β_sp and γ1_sp relaxations and significantly lowered their characteristic frequencies. Our observations indicate that the glycophorin C attachment to spectrin has nucleophilic centers whose saturation disconnects this attachment and inhibits the β_sp relaxation, whereas at band 3-spectrin attachment site, it is the saturation of electrophilic centers that weakens this attachment and inhibits the γ1_sp relaxation.