Bioelectromagnetics最新文献

The widespread deployment of 5G wireless networks alongside existing GSM technologies has increased the need to assess potential biological effects of co-exposure to multiple radiofrequency electromagnetic fields (RF-EMF). This study evaluates the in-vitro impact of simultaneous exposure to 5G-modulated 3.5 GHz and GSM-modulated 1.8 GHz signals on neuronal electrical activity, mitochondrial reactive oxygen species (ROS) production, and cellular stress protein responses in neurons and skin fibroblasts. Primary cortical neurons and human immortalized skin fibroblasts were exposed to RF-EMF at specific absorption rates (SAR) of 1 or 4 W/kg for 15 min or 24 h, respectively. Neuronal activity was analyzed using multi-electrode arrays (MEAs), mitochondrial ROS production was measured using MitoSOX Red, and stress protein activity was assessed using bioluminescence resonance energy transfer (BRET) assays targeting RAS, PML, and HSF1 proteins. The results indicate no significant effects on the mean bursting rate (MBR) or mean firing rate (MFR) of cortical neurons, consistent with previous findings at similar SAR levels. Mitochondrial ROS production in fibroblasts also remained unaffected by RF-EMF co-exposure. BRET assays detected minor variations in the basal activity of RAS and PML and in the maximal efficacy of PMA and As₂O₃ to activate these pathways. However, these effects were small, near the detection threshold, and showed no consistent pattern across different tests or chemical treatments. No change was observed in HSF1 basal activity or responsiveness to MG132. These findings suggest that co-exposure to 5G- and GSM-modulated RF-EMF at SAR levels up to 4 W/kg does not produce conclusive evidence of marked biological effects under the tested conditions. Observed variations, when present, are of low amplitude and likely to fall within the range of experimental variability.

Compliance testing of wireless devices with absorbed power density (APD) limits requires body models that conservatively reproduce the absorption characteristics of human skin. Previous studies indicate that impedance-matching effects are caused by the stratum corneum (SC) layer. The objective of this study is to develop a single macroscopic dielectric model reproducing absorption of electromagnetic fields by the skin up to 110 GHz. The reflection coefficient of the skin of human volunteers was measured at frequencies of 15 to 43 GHz with open waveguide probes, complementing previous data from 45 to 110 GHz. The measurements were made at various regions of the body. The statistical analysis of the results shows that the reflection coefficient in dB follows normal distribution in regions with thin SC, which permits the development of a conservative skin model. In regions with thick SC, for example, the palms, the reflection coefficient is not normally distributed because the thickness of the SC depends on the mechanical stress the hands are exposed to. The measured data allow the derivation of dispersive two-layer models representing absorption and reflection at the skin surface with known uncertainty. The models can be used to conservatively demonstrate compliance with the APD limits of wireless devices in any of the 5G and 6G bands.

Electromagnetic (EM) safety guidelines are designed to protect the general public and workers from the risks posed by exposure to EM sources of all types, with the exception of medical EM sources. However, it has never been systematically evaluated whether individuals with conductive implants are also protected by these guidelines or whether the local field enhancement due to presence of the implant may pose an unacceptable risk under certain realistic exposure conditions. To address this important knowledge and regulatory gap, we first evaluated the upper bound of the local enhancement of bare and insulated generic implants of 0.5 λ (approximately equal to resonant) and 0.1 λ lengths, but restricted the maximum length to 2 m, as a function of tissue properties and frequency (10 kHz to 1 GHz). Results for uniform electric field excitation showed local enhancement of psSAR_10mg and of locally averaged E-field, respectively, compared to the background in the presence of a generic implant of 10 dB (1 GHz) to over 100 dB at frequencies under 100 MHz. In the next step, we tested the hypothesis that fields induced inside the human body by realistic near-field sources are not sufficiently uniform to generate results in enhancement that could pose unacceptable risk. Common implant trajectories were inserted into the Virtual Population human anatomical model Ella V3.0, and the model was exposed to the following conditions (i) a standard source representing a wireless power transfer source operating at 85 kHz and (ii) a dipole source that operates at 450 MHz within the current exposure limits. Results show that the safety limit is exceeded at the tip of the implant by a factor of > 10 ( > 20 dB) or > 115 V/m at 85 kHz, whereas the locally induced specific absorption rate averaged over 10 mg at 450 MHz was 7.9 W/kg, resulting in a temperature increase after 6 min of < 0.4 K. Hence, as the hypothesis was falsified at frequencies < 450 MHz, patients with implants are inadequately protected by current safety and product guidelines. In the discussions, proposals for how to close this regulatory gap are provided. Bioelectromagnetics. 00:00–00, 2025. © 2025 Bioelectromagnetics Society.

In order to understand Idiopathic Environmental Intolerance attributed to Electromagnetic Fields (IEI-EMF), it has been argued that it is crucial to test for effects of radiofrequency electromagnetic fields (RF-EMF) on biomarkers, given that they can be more objective than symptom reports. While no clear evidence links RF-EMF exposure to biomarker changes, research remains limited and largely speculative due to the lack of known bioeffect mechanisms. However, there is in vitro evidence that cortisol is affected by heating, which, as RF-EMF causes heating, raises the possibility that RF-EMF exposure may increase cortisol via thermally mediated processes. If cortisol is affected by RF-EMF exposure, it may form part of a broader aetiology of IEI-EMF, where RF-EMF-induced physiological (cortisol) inputs first generate somatic sensations, which are then fostered by expectancy or learning-based processes to generate symptoms. However, studies investigating whether RF-EMF exposure influences cortisol have reported inconsistent, but mostly null results, and many suffer from methodological issues. The current study was designed with several methodological improvements to determine whether RF-EMF affects cortisol. Seventy-two participants completed a randomized, double-blind, counterbalanced provocation study where they were exposed to both active (2 W/kg peak SAR_10g in head) and sham RF-EMF (0 W/kg peak SAR_10g in head). Despite implementing several methodological improvements, the current study failed to find an effect of RF-EMF exposure on salivary cortisol concentration. This study provides a valuable direction for future research and stresses the importance of establishing and testing theoretically plausible interactions between low-level RF-EMF exposure, the human body, and IEI-EMF symptoms.

This study evaluates radiofrequency electromagnetic field (RF-EMF) exposure in 5G networks using a dual approach that combines theoretical extrapolations and direct measurements in diverse semiurban and urban environments, specifically on the campus of the Polytechnic University of Valencia. Measurements were conducted using personal exposimeters under active traffic conditions on the 5G network, complemented by a code-selective measurement system based on an R&S TSME6 scanner. This approach enabled the calculation of maximum theoretical exposure by detailed analysis of 5G signals and the capture of key parameters such as cell ID and beam indices at 16 representative points across the campus. For precise spatial visualization, Kriging interpolation techniques in ArcGIS were employed to generate continuous exposure maps illustrating the spatial distribution of RF-EMF in the study area. The results indicate that both the extrapolated theoretical values and measured levels align with the limits recommended by the ICNIRP, even under high data demand scenarios, supporting current safety assessments of 5G infrastructure regarding electromagnetic exposure. The correlation between theoretical and instantaneous exposures validates the applied methodology and its effectiveness in assessing exposure in diverse environments. This study provides a robust framework for future research and highlights the importance of continuous monitoring to ensure public safety during the deployment of new telecommunications infrastructure in urban areas. Bioelectromagnetics. 00:00–00, 2025. © 2025 Bioelectromagnetics Society.

This study assesses the exposure to 5G radio frequency electromagnetic fields (RF EMF) across four European countries. Spot measurements were conducted indoor and outdoor in both public spaces and educational institutions, encompassing urban and rural environments. In total, 146 measurements were performed in 2023, divided over Belgium (47), Switzerland (38), Hungary (30) and Poland (31). At 34.9% of all measurement locations a 5G connection to 3.6 GHz was established. The average cumulative incident power density (S_avg) and maximum cumulative incident power density (S_max) were determined, for both “background” exposure (no 5G user equipment; No UE) and worst-case exposure (maximum downlink with 5G user equipment; Max DL). Furthermore, 3.6 GHz 5G-specific average S_avg,5G and maximum S_max,5G incident power density are considered as well. For the No UE scenario, the highest S_max is 17.6 mW/m², while for the Max DL, the highest S_max is 23.3 mW/m². Both values are well within the ICNIRP guidelines. The highest S_max,5G measured over all countries and scenarios was 10.4 mW/m², which is 3.2% of the frequency-specific ICNIRP guidelines. Additionally, a comparison was made between big cities, secondary cities, and villages for all four countries. The ratio of power density measured in rural areas was significantly lower than in urban areas (−4.8 to −10.4 dB). Under LOS conditions, the average incident power density was 2.3 mW/m², whereas under NLOS conditions, the average incident power density decreases to 0.9 mW/m². Furthermore, the relative variation increases under NLOS scenarios. Lastly, an analysis was performed regarding the power density in educational institutions compared to all other measurement locations, both indoors and outdoors for the different city types. The measured incident power density is not extensively lower in or around schools compared to public places, neither in the big cities, secondary cities, or the villages.

In this study, a comprehensive approach for the experimental assessment of the absorbed power density (APD) is developed. The method includes several novel components: (i) a specialized probe, (ii) a composite phantom, (iii) a reconstruction technique, (iv) a calibration method, and (v) a validation process. The described solution has been developed for the frequency range from 24 to 30 GHz, but can be extended to all frequency bands between 10 and 45 GHz. A novel composite phantom emulates the reflection and transmission coefficients of human skin for propagating and evanescent modes, while its increased penetration depth, in comparison to dermis tissue, enables the measurement of the induced electromagnetic fields (EMFs) with a new miniaturized dosimetric broadband probe. The implementation has a wide dynamic range and sufficient spatial resolution to use it for type approval of mobile devices. Its probe is calibrated with low uncertainty in a novel, traceable setup. A set of reference antennas with known numerical target values for the APD has been compiled to validate the measurement system. The validation demonstrates that the deviation is within the expanded uncertainty of 1.6 dB for pAPD and $��\; ��<��$ 1.5 dB for psAPD.