The effect of exposure to radiofrequency fields on cancer risk in the general and working population: A systematic review of human observational studies - Part I: Most researched outcomes.

BACKGROUND: The objective of this review was to assess the quality and strength of the evidence provided by human observational studies for a causal association between exposure to radiofrequency electromagnetic fields (RF-EMF) and risk of the most investigated neoplastic diseases. METHODS: Eligibility criteria: We included cohort and case-control studies of neoplasia risks in relation to three types of exposure to RF-EMF: near-field, head-localized, exposure from wireless phone use (SR-A); far-field, whole body, environmental exposure from fixed-site transmitters (SR-B); near/far-field occupational exposures from use of hand-held transceivers or RF-emitting equipment in the workplace (SR-C). While no restrictions on tumour type were applied, in the current paper we focus on incidence-based studies of selected "critical" neoplasms of the central nervous system (brain, meninges, pituitary gland, acoustic nerve) and salivary gland tumours (SR-A); brain tumours and leukaemias (SR-B, SR-C). We focussed on investigations of specific neoplasms in relation to specific exposure sources (i.e. E-O pairs), noting that a single article may address multiple E-O pairs. INFORMATION SOURCES: Eligible studies were identified by literature searches through Medline, Embase, and EMF-Portal. Risk-of-bias (RoB) assessment: We used a tailored version of the Office of Health Assessment and Translation (OHAT) RoB tool to evaluate each study's internal validity. At the summary RoB step, studies were classified into three tiers according to their overall potential for bias (low, moderate and high). DATA SYNTHESIS: We synthesized the study results using random effects restricted maximum likelihood (REML) models (overall and subgroup meta-analyses of dichotomous and categorical exposure variables), and weighted mixed effects models (dose-response meta-analyses of lifetime exposure intensity). Evidence assessment: Confidence in evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. RESULTS: We included 63 aetiological articles, published between 1994 and 2022, with participants from 22 countries, reporting on 119 different E-O pairs. RF-EMF exposure from mobile phones (ever or regular use vs no or non-regular use) was not associated with an increased risk of glioma [meta-estimate of the relative risk (mRR) = 1.01, 95 % CI = 0.89-1.13), meningioma (mRR = 0.92, 95 % CI = 0.82-1.02), acoustic neuroma (mRR = 1.03, 95 % CI = 0.85-1.24), pituitary tumours (mRR = 0.81, 95 % CI = 0.61-1.06), salivary gland tumours (mRR = 0.91, 95 % CI = 0.78-1.06), or paediatric (children, adolescents and young adults) brain tumours (mRR = 1.06, 95 % CI = 0.74-1.51), with variable degree of across-study heterogeneity (I2 = 0 %-62 %). There was no observable increase in mRRs for the most investigated neoplasms (glioma, meningioma, and acoustic neuroma) with increasing time since start (TSS) use of mobile phones, cumulative call time (CCT), or cumulative number of calls (CNC). Cordless phone use was not significantly associated with risks of glioma [mRR = 1.04, 95 % CI = 0.74-1.46; I2 = 74 %) meningioma, (mRR = 0.91, 95 % CI = 0.70-1.18; I2 = 59 %), or acoustic neuroma (mRR = 1.16; 95 % CI = 0.83-1.61; I2 = 63 %). Exposure from fixed-site transmitters (broadcasting antennas or base stations) was not associated with childhood leukaemia or paediatric brain tumour risks, independently of the level of the modelled RF exposure. Glioma risk was not significantly increased following occupational RF exposure (ever vs never), and no differences were detected between increasing categories of modelled cumulative exposure levels. DISCUSSION: In the sensitivity analyses of glioma, meningioma, and acoustic neuroma risks in relation to mobile phone use (ever use, TSS, CCT, and CNC) the presented results were robust and not affected by changes in study aggregation. In a leave-one-out meta-analyses of glioma risk in relation to mobile phone use we identified one influential study. In subsequent meta-analyses performed after excluding this study, we observed a substantial reduction in the mRR and the heterogeneity between studies, for both the contrast Ever vs Never (regular) use (mRR = 0.96, 95 % CI = 0.87-1.07, I2 = 47 %), and in the analysis by increasing categories of TSS ("<5 years": mRR = 0.97, 95 % CI = 0.83-1.14, I2 = 41 %; "5-9 years ": mRR = 0.96, 95 % CI = 0.83-1.11, I2 = 34 %; "10+ years": mRR = 0.97, 95 % CI = 0.87-1.08, I2 = 10 %). There was limited variation across studies in RoB for the priority domains (selection/attrition, exposure and outcome information), with the number of studies evenly classified as at low and moderate risk of bias (49 % tier-1 and 51 % tier-2), and no studies classified as at high risk of bias (tier-3). The impact of the biases on the study results (amount and direction) proved difficult to predict, and the RoB tool was inherently unable to account for the effect of competing biases. However, the sensitivity meta-analyses stratified on bias-tier, showed that the heterogeneity observed in our main meta-analyses across studies of glioma and acoustic neuroma in the upper TSS stratum (I2 = 77 % and 76 %), was explained by the summary RoB-tier. In the tier-1 study subgroup, the mRRs (95 % CI; I2) in long-term (10+ years) users were 0.95 (0.85-1.05; 5.5 %) for glioma, and 1.00 (0.78-1.29; 35 %) for acoustic neuroma. The time-trend simulation studies, evaluated as complementary evidence in line with a triangulation approach for external validity, were consistent in showing that the increased risks observed in some case-control studies were incompatible with the actual incidence rates of glioma/brain cancer observed in several countries and over long periods. Three of these simulation studies consistently reported that RR estimates > 1.5 with a 10+ years induction period were definitely implausible, and could be used to set a "credibility benchmark". In the sensitivity meta-analyses of glioma risk in the upper category of TSS excluding five studies reporting implausible effect sizes, we observed strong reductions in both the mRR [mRR of 0.95 (95 % CI = 0.86-1.05)], and the degree of heterogeneity across studies (I2 = 3.6 %). CONCLUSIONS: Consistently with the published protocol, our final conclusions were formulated separately for each exposure-outcome combination, and primarily based on the line of evidence with the highest confidence, taking into account the ranking of RF sources by exposure level as inferred from dosimetric studies, and the external coherence with findings from time-trend simulation studies (limited to glioma in relation to mobile phone use). For near field RF-EMF exposure to the head from mobile phone use, there was moderate certainty evidence that it likely does not increase the risk of glioma, meningioma, acoustic neuroma, pituitary tumours, and salivary gland tumours in adults, or of paediatric brain tumours. For near field RF-EMF exposure to the head from cordless phone use, there was low certainty evidence that it may not increase the risk of glioma, meningioma or acoustic neuroma. For whole-body far-field RF-EMF exposure from fixed-site transmitters (broadcasting antennas or base stations), there was moderate certainty evidence that it likely does not increase childhood leukaemia risk and low certainty evidence that it may not increase the risk of paediatric brain tumours. There were no studies eligible for inclusion investigating RF-EMF exposure from fixed-site transmitters and critical tumours in adults. For occupational RF-EMF exposure, there was low certainty evidence that it may not increase the risk of brain cancer/glioma, but there were no included studies of leukemias (the second critical outcome in SR-C). The evidence rating regarding paediatric brain tumours in relation to environmental RF exposure from fixed-site transmitters should be interpreted with caution, due to the small number of studies. Similar interpretative cautions apply to the evidence rating of the relation between glioma/brain cancer and occupational RF exposure, due to differences in exposure sources and metrics across the few included studies. OTHER: This project was commissioned and partially funded by the World Health Organization (WHO). Co-financing was provided by the New Zealand Ministry of Health; the Istituto Superiore di Sanità in its capacity as a WHO Collaborating Centre for Radiation and Health; and ARPANSA as a WHO Collaborating Centre for Radiation Protection. REGISTRATION: PROSPERO CRD42021236798. Published protocol: [(Lagorio et al., 2021) DOI https://doi.org/10.1016/j.envint.2021.106828].

Effects of changes in the waveform and frequency of radio frequency energy on tissue ablation range.

This study reports the effects of changes in the waveform and frequency of radio frequency (RF) energy on the tissue ablation range. We developed a 70-watt RFA generator that provides sine and square waves and allows frequency control between 10 Hz and 500 kHz. The changes in the ablation range according to the waveform and frequency were observed using the developed generator. In the waveform variation test, the distance between the electrodes and the electrode type were changed for both waveforms with the frequency set to 500 kHz. In the frequency variation test, the waveform and electrode type were changed with the frequency set to 10, 100, and 500 kHz, while the distance between the electrodes was set to 20 mm. A fixed 45 voltage was applied using the bipolar method. RF energy was applied for 90 s in vitro. The temperature was regulated to not exceed 70°C. The ablation range was calculated using ImageJ software. The analysis results showed that the ablation range was larger with the square wave than with the sine wave and at 10 kHz than at 500 kHz. The developed generator can advance research on ablation area and depth in RF ablation.

Effects of website-based risk communication of radio-frequency electromagnetic fields on general public.

Background: Radio-frequency electromagnetic fields (RF-EMFs) are utilized in communications and appliances and are indispensable in daily life. However, some people have concerns about the adverse health effects of RF-EMFs; therefore, effective risk communication (RC) is needed in this field. Objective: In this study, we investigate public attitudes towards RF-EMFs and examine the impact of RC via a website on these attitudes and objective knowledge. Methods: Three web surveys were conducted over 10 weeks with the same participants. The questionnaires were conducted at three different time points with 5-week intervals: baseline survey (T1), RC evaluation survey (T2), and follow-up survey (T3). Participants of T2 were randomly recruited from among those of T1, and participants of T3 were randomly selected from among the T2 respondents. Approximately half of the respondents in each of T2 and T3 were assigned to the control group. Twelve items regarding attitudes toward RF-EMFs and objective knowledge were evaluated in all surveys (T1-T3). After removing low-engagement data, the number of valid answers was 782 in T3. Differences between T1 and T2 (Sub T1-T2) and T1 and T3 (Sub T1-T3) were analyzed. Participant selection was randomized and the authors were blind to this selection until analysis. Results: Four clusters were identified: Cluster 1 (Non-anxious, 25.0%), Cluster 2 (Anxious, 16.0%), Cluster 3 (Low-interest, 40.5%), and Cluster 4 (High-interest, 18.5%). A decrease in subjective RF-EMF exposure levels was noted in Cluster 2 immediately after website viewing. Temporary increases and decreases in health concerns about RF-EMF usage activities were observed in Clusters 1 and 2, respectively, immediately after viewing. Clusters 1 and 3 showed a temporal decrease in needs for RF-EMF usage activities at T2 but it returned to the baseline level 5 weeks later. Cluster 4 was less responsive to the risk communication. Subanalysis stratified by gender and age showed fluctuations in responses, especially in Clusters 1 and 2. Conclusion: We demonstrate the effectiveness of RF-EMF risk communication via websites, particularly for Cluster 2. The results of this study showed that offering objective and comprehensible information through a website can significantly reduce concerns and perceived risks related to RF-EMFs.

Ultrasonic Assessment of Liver Fibrosis Using One-Dimensional Convolutional Neural Networks Based on Frequency Spectra of Radiofrequency Signals with Deep Learning Segmentation of Liver Regions in B-Mode Images: A Feasibility Study.

The early detection of liver fibrosis is of significant importance. Deep learning analysis of ultrasound backscattered radiofrequency (RF) signals is emerging for tissue characterization as the RF signals carry abundant information related to tissue microstructures. However, the existing methods only used the time-domain information of the RF signals for liver fibrosis assessment, and the liver region of interest (ROI) is outlined manually. In this study, we proposed an approach for liver fibrosis assessment using deep learning models on ultrasound RF signals. The proposed method consisted of two-dimensional (2D) convolutional neural networks (CNNs) for automatic liver ROI segmentation from reconstructed B-mode ultrasound images and one-dimensional (1D) CNNs for liver fibrosis stage classification based on the frequency spectra (amplitude, phase, and power) of the segmented ROI signals. The Fourier transform was used to obtain the three kinds of frequency spectra. Two classical 2D CNNs were employed for liver ROI segmentation: U-Net and Attention U-Net. ROI spectrum signals were normalized and augmented using a sliding window technique. Ultrasound RF signals collected (with a 3-MHz transducer) from 613 participants (Group A) were included for liver ROI segmentation and those from 237 participants (Group B) for liver fibrosis stage classification, with a liver biopsy as the reference standard (Fibrosis stage: F0 = 27, F1 = 49, F2 = 51, F3 = 49, F4 = 61). In the test set of Group A, U-Net and Attention U-Net yielded Dice similarity coefficients of 95.05% and 94.68%, respectively. In the test set of Group B, the 1D CNN performed the best when using ROI phase spectrum signals to evaluate liver fibrosis stages ≥F1 (area under the receive operating characteristic curve, AUC: 0.957; accuracy: 89.19%; sensitivity: 85.17%; specificity: 93.75%), ≥F2 (AUC: 0.808; accuracy: 83.34%; sensitivity: 87.50%; specificity: 78.57%), and ≥F4 (AUC: 0.876; accuracy: 85.71%; sensitivity: 77.78%; specificity: 94.12%), and when using the power spectrum signals to evaluate ≥F3 (AUC: 0.729; accuracy: 77.14%; sensitivity: 77.27%; specificity: 76.92%). The experimental results demonstrated the feasibility of both the 2D and 1D CNNs in liver parenchyma detection and liver fibrosis characterization. The proposed methods have provided a new strategy for liver fibrosis assessment based on ultrasound RF signals, especially for early fibrosis detection. The findings of this study shed light on deep learning analysis of ultrasound RF signals in the frequency domain with automatic ROI segmentation.

Penetrating Barriers: Noncontact Measurement of Vital Bio Signs Using Radio Frequency Technology.

The noninvasive measurement and sensing of vital bio signs, such as respiration and cardiopulmonary parameters, has become an essential part of the evaluation of a patient's physiological condition. The demand for new technologies that facilitate remote and noninvasive techniques for such measurements continues to grow. While previous research has made strides in the continuous monitoring of vital bio signs using lasers, this paper introduces a novel technique for remote noncontact measurements based on radio frequencies. Unlike laser-based methods, this innovative approach offers the advantage of penetrating through walls and tissues, enabling the measurement of respiration and heart rate. Our method, diverging from traditional radar systems, introduces a unique sensing concept that enables the detection of micro-movements in all directions, including those parallel to the antenna surface. The main goal of this work is to present a novel, simple, and cost-effective measurement tool capable of indicating changes in a subject's condition. By leveraging the unique properties of radio frequencies, this technique allows for the noninvasive monitoring of vital bio signs without the need for physical contact or invasive procedures. Moreover, the ability to penetrate barriers such as walls and tissues opens new possibilities for remote monitoring in various settings, including home healthcare, hospital environments, and even search and rescue operations. In order to validate the effectiveness of this technique, a series of experiments were conducted using a prototype device. The results demonstrated the feasibility of accurately measuring respiration patterns and heart rate remotely, showcasing the potential for real-time monitoring of a patient's physiological parameters. Furthermore, the simplicity and low-cost nature of the proposed measurement tool make it accessible to a wide range of users, including healthcare professionals, caregivers, and individuals seeking to monitor their own health.

A Quantitative Comparison of 31P Magnetic Resonance Spectroscopy RF Coil Sensitivity and SNR between 7T and 10.5T Human MRI Scanners Using a Loop-Dipole 31P-1H Probe.

In vivo phosphorus-31 (31P) magnetic resonance spectroscopy (MRS) imaging (MRSI) is an important non-invasive imaging tool for studying cerebral energy metabolism, intracellular nicotinamide adenine dinucleotide (NAD) and redox ratio, and mitochondrial function. However, it is challenging to achieve high signal-to-noise ratio (SNR) 31P MRS/MRSI results owing to low phosphorus metabolites concentration and low phosphorous gyromagnetic ratio (γ). Many works have demonstrated that ultrahigh field (UHF) could significantly improve the 31P-MRS SNR. However, there is a lack of studies of the 31P MRSI SNR in the 10.5 Tesla (T) human scanner. In this study, we designed and constructed a novel 31P-1H dual-frequency loop-dipole probe that can operate at both 7T and 10.5T for a quantitative comparison of 31P MRSI SNR between the two magnetic fields, taking into account the RF coil B1 fields (RF coil receive and transmit fields) and relaxation times. We found that the SNR of the 31P MRS signal is 1.5 times higher at 10.5T as compared to 7T, and the power dependence of SNR on magnetic field strength (B0) is 1.9.

The effect of exposure to radiofrequency electromagnetic fields on cognitive performance in human experimental studies: Systematic review and meta-analyses.

BACKGROUND: The objective of this review is to evaluate the associations between short-term exposure to radiofrequency electromagnetic fields (RF-EMF) and cognitive performance in human experimental studies. METHODS: Online databases (PubMed, Embase, Scopus, Web of Science and EMF-Portal) were searched for studies that evaluated effects of exposure to RF-EMF on seven domains of cognitive performance in human experimental studies. The assessment of study quality was based on the Risk of Bias (RoB) tool developed by the Office of Health Assessment and Translation (OHAT). Random effects meta-analyses of Hedges's g were conducted separately for accuracy- and speed-related performance measures of various cognitive domains, for which data from at least two studies were available. Finally, the certainty of evidence for each identified outcome was assessed according to Grading of Recommendations Assessment, Development, and Evaluation (GRADE). RESULTS: 57,543 records were identified and 76 studies (80 reports) met the inclusion criteria. The included 76 studies with 3846 participants, consisting of humans of different age, sex and health status from 19 countries, were conducted between 1989 and 2021. Quantitative data from 50 studies (52 reports) with 2433 participants were included into the meta-analyses. These studies were performed in 15 countries between 2001 and 2021. The majority of the included studies used head exposure with GSM 900 uplink. None of the meta-analyses observed a statistically significant effect of RF-EMF exposure compared to sham on cognitive performance as measured by the confidence interval surrounding the Hedges's g or the significance of the z-statistic. For the domain Orientation and Attention, subclass Attention - Attentional Capacity RF-EMF exposure results in little to no difference in accuracy (Hedges's g 0.024, 95 % CI [-0.10; 0.15], I2 = 28 %, 473 participants). For the domain Orientation and Attention, subclass Attention - Concentration / Focused Attention RF-EMF exposure results in little to no difference in speed (Hedges's g 0.005, 95 % CI [-0.17; 0.18], I2 = 7 %, 132 participants) and probably results in little to no difference in accuracy; it does not reduce accuracy (Hedges's g 0.097, 95 % CI [-0.05; 0.24], I2 = 0 %, 217 participants). For the domain Orientation and Attention, subclass Attention - Vigilance RF-EMF exposure probably results in little to no difference in speed and does not reduce speed (Hedges's g 0.118, 95 % CI [-0.04; 0.28], I2 = 41 %, 247 participants) and results in little to no difference in accuracy (Hedges's g 0.042, 95 % CI, [-0.09; 0.18], I2 = 0 %, 199 participants). For the domain Orientation and Attention, subclass Attention - Selective Attention RF-EMF exposure probably results in little to no difference in speed and does not reduce speed (Hedges's g 0.080, 95 % CI [-0.09; 0.25], I2 = 63 %, 452 participants); it may result in little to no difference in accuracy, but it probably does not reduce accuracy (Hedges's g 0.178, 95 % CI [-0.02; 0.38], I2 = 68 %, 480 participants). For the domain Orientation and Attention, subclass Attention - Divided Attention RF-EMF exposure results in little to no difference in speed (Hedges's g -0.010, 95 % CI [-0.14; 0.12], I2 = 5 %, 307 participants) and may result in little to no difference in accuracy (Hedges's g -0.089, 95 % CI [-0.35; 0.18], I2 = 53 %, 167 participants). For the domain Orientation and Attention, subclass Processing Speed - Simple Reaction Time Task RF-EMF exposure results in little to no difference in speed (Hedges's g 0.069, 95 % CI [-0.02; +0.16], I2 = 29 %, 820 participants). For the domain Orientation and Attention, subclass Processing Speed - 2-Choice Reaction Time Task RF-EMF exposure results in little to no difference in speed (Hedges's g -0.023, 95 % CI [-0.13; 0.08], I2 = 0 %, 401 participants), and may result in little to no difference in accuracy (Hedges's g -0.063, 95 % CI [-0.38; 0.25], I2 = 63 %, 117 participants). For the domain Orientation and Attention, subclass Processing Speed - >2-Choice Reaction Time Task RF-EMF exposure results in little to no difference in speed (Hedges's g -0.054, 95 % CI [-0.14; 0.03], I2 = 0 %, 544 participants) and probably results in little to no difference in accuracy (Hedges's g -0.129, 95 % CI [-0.30; 0.04], I2 = 0 %, 131 participants). For the domain Orientation and Attention, subclass Processing Speed - Other Tasks RF-EMF exposure probably results in little to no difference in speed and does not reduce speed (Hedges's g 0.067, 95 % CI [-0.12; 0.26], I2 = 38 %, 249 participants); it results in little to no difference in accuracy (Hedges's g 0.036, 95 % CI [-0.08; 0.15], I2 = 0 %, 354 participants). For the domain Orientation and Attention, subclass Working Memory - n-back Task (0-3-back) we found Hedges's g ranging from -0.090, 95 % CI [-0.18; 0.01] to 0.060, 95 % CI [-0.06; 0.18], all I2 = 0 %, 237 to 474 participants, and conclude that RF-EMF exposure results in little to no difference in both speed and accuracy. For the domain Orientation and Attention, subclass Working Memory - Mental Tracking RF-EMF exposure results in little to no difference in accuracy (Hedges's g -0.047, 95 % [CI -0.15; 0.05], I2 = 0 %, 438 participants). For the domain Perception, subclass Visual and Auditory Perception RF-EMF exposure may result in little to no difference in speed (Hedges's g -0.015, 95 % CI [-0.23; 0.195], I2 = 0 %, 84 participants) and probably results in little to no difference in accuracy (Hedges's g 0.035, 95 % CI [-0.13; 0.199], I2 = 0 %, 137 participants). For the domain Memory, subclass Verbal and Visual Memory RF-EMF exposure probably results in little to no difference in speed and does not reduce speed (Hedges's g 0.042, 95 % CI [-0.15; 0.23], I2 = 0 %, 102 participants); it may result in little to no difference in accuracy (Hedges's g -0.087, 95 % CI [-0.38; 0.20], I2 = 85 %, 625 participants). For the domain Verbal Functions and Language Skills, subclass Verbal Expression, a meta-analysis was not possible because one of the two included studies did not provide numerical values. Results of both studies did not indicate statistically significant effects of RF-EMF exposure on both speed and accuracy. For the domain Construction and Motor Performance, subclass Motor Skills RF-EMF exposure may reduce speed, but the evidence is very uncertain (Hedges's g -0.919, 95 % CI [-3.09; 1.26], I2 = 96 %, 42 participants); it probably results in little to no difference in accuracy and does not reduce accuracy (Hedges's g 0.228, 95 % CI [-0.01; 0.46], I2 = 0 %, 109 participants). For the domain Concept Formation and Reasoning, subclass Reasoning RF-EMF exposure results in little to no difference in speed (Hedges's g 0.010, 95 % CI [-0.11; 0.13], I2 = 0 %, 263 participants) and probably results in little to no difference in accuracy and does not reduce accuracy (Hedges's g 0.051, 95 % CI [-0.14; 0.25], I2 = 0 %, 100 participants). For the domain Concept Formation and Reasoning, subclass Mathematical Procedures RF-EMF exposure results in little to no difference in speed (Hedges's g 0.033, 95 % CI [-0.12; 0.18], I2 = 0 %, 168 participants) and may result in little to no difference in accuracy but probably does not reduce accuracy (Hedges's g 0.232, 95 % CI [-0.12; +0.59], I2 = 86 %, 253 participants). For the domain Executive Functions there were no studies. DISCUSSION: Overall, the results from all domains and subclasses across their speed- and accuracy-related outcome measures according to GRADE provide high to low certainty of evidence that short-term RF-EMF exposure does not reduce cognitive performance in human experimental studies. For 16 out of 35 subdomains some uncertainty remains, because of limitations in the study quality, inconsistency in the results or imprecision of the combined effect size estimate. Future research should focus on construction and motor performance, elderly, and consideration of both sexes. OTHER: This review was partially funded by the WHO radioprotection programme. The protocol for this review was registered in Prospero reg. no. CRD42021236168 and published in Environment International (Pophof et al. 2021).

The histological and biochemical analysis of the effects of radiofrequency radiation on testis tissue of rats and the protective effect of melatonin.

Background/aim: Primarily due to wireless communication devices, especially mobile phones, there has been a steady rise in the intensity of nonionizing radiofrequency radiation (RFR). In recent years, increased human health problems raised concerns about whether there is a positive relationship between intense exposure to RFR and public health. The present study aims to investigate the effects of GSM-like RFR exposure on the male reproductive system and the impact of melatonin treatment (synergistic, antagonist, or additive). Materials and methods: Thirty-six male Wistar Albino rats were used and separated into six groups: i. Control; ii. Sham; iii. RFR exposure; iv. Control-melatonin; v. Sham-melatonin; vi. Melatonin + RFR exposure. Animals were exposed to 2600 MHz RFR with electric (E) field levels of 21.74 V/m for 30 min per day, 5 days per week, for 4 weeks. All testicular tissue samples were evaluated under a light microscope for hematoxylin-eosin staining. Biochemical analyses were performed by measuring malondialdehyde, total nitric oxide, glutathione, and glutathione peroxidase levels. We evaluated the combined effects of prolonged RFR exposure and melatonin treatment on ROS-mediated structural changes in testicular tissues. Results: Results showed that reactive intermediates (malondialdehyde and total nitric oxide) increased significantly with RFR exposure, while the protective effect of melatonin effectively reduced the radical levels of the tissues. Histological evaluation revealed a decrease in cell population and connective tissue elements under RFR exposure, accompanied by marked edema in the testicular tissues. Conclusion: The structural and functional effects of prolonged RFR exposure might be ROS-based. Moreover, these adverse effects might be compensated with externally treated supplements. There is a need for new extensive research.

Combining radio frequency heating and alkaline treatment for enhancement of sludge disintegration and volatile fatty acids production from anaerobic fermentation.

Sludge pretreatment plays a crucial role in solubilizing particulate matters to release organic matter for subsequent anaerobic fermentation (AF). This study innovatively combines radio frequency (RF) heating and alkaline treatment, and finds that the combined pretreatment achieved a sludge disintegration rate of 35.11 %, which is 15.19 % and 8.48 % higher than single RF or alkaline pretreatment. The dissociated ions from the alkali are conducive to RF action on sludge. Furthermore, the combined pretreatment significantly benefits the subsequent AF experiments, resulting in a 9-fold increase in volatile fatty acids production. Considering cost-effectiveness, the optimal operating condition is a 10-minute RF treatment at pH 10 with a total cost of 4.35 × 10-3 dollars per kg soluble chemical oxygen demand (SCOD) increased. These findings provide a foundational basis for the development of a novel technology for sludge pretreatment.

Enhanced Brain Clearance of Tau and Amyloid-ß in Alzheimer's Disease Patients by Transcranial Radiofrequency Wave Treatment: A Central Role of Vascular Endothelial Growth Factor (VEGF).

Background: While drainage/removal of fluid and toxins from the brain by cerebrospinal fluid (CSF) directly into venous blood is well-known, a second drainage route has recently been (re)discovered-meningeal lymphatic vessels (mLVs)-which are responsible for up to half of total brain fluid/toxin drainage. The cytokine vascular endothelial growth factor (VEGF) increases mLV diameter and numbers to increase mLV drainage, resulting in increased mLV drainage. Alzheimer's disease (AD) is characterized by low plasma and CSF levels of VEGF. Objective: To determine if non-invasive transcranial radiofrequency wave treatment (TRFT), through modulation of VEGF levels in blood and CSF, can affect removal of toxins tau and amyloid-ß (Aß) from the brain. Methods: Eight mild/moderate AD subjects were given twice-daily 1-hour TRFT sessions at home by their caregivers. Blood and CSF samples were taken at baseline and following completion of 2 months of TRFT. Results: In plasma and/or CSF, strong baseline correlations between VEGF levels and AD markers (t-tau, p-tau, Aß1-40, Aß1-42) were eliminated by TRFT. This effect was primarily due to TRFT-induced increases in VEGF levels in AD subjects with low or unmeasurable "baseline" VEGF levels. These increased VEGF levels were associated with increased clearance/drainage of tau and Aß from the brain, likely through VEGF's actions on mLVs. Conclusions: A new mechanism of TRFT is identified (facilitation of brain tau and Aß clearance via VEGF) that is likely contributory to TRFT's reversal of cognitive impairment in AD subjects. TRFT may be particularly effective for cognitive benefit in AD subjects who have low VEGF levels.

Radiofrequency-responsive black phosphorus nanogel crosslinked with cisplatin for precise synergy in multi-modal tumor therapies.

Radiofrequency-responsive nanoparticles (RFNPs) have drawn increasingly attentions as RF energy absorbing antenna to enhance antitumor efficacy of radiofrequency ablation (RFA). However, it remains a huge challenge for inorganic RFNPs to precisely synergize RFA with other antitumor modes in a clinically acceptable way on bio-safety and bio-compatibility. In this work, RF-responsive black phosphorus (BP) nanogel (BP-Pt@PNA) was successfully fabricated by crosslinking coordination of cisplatin with BP and temperature sensitive polymer PNA. BP-Pt@PNA exhibited strong RF-heating effect and RF-induced pulsatile release of cisplatin. Under RF irradiation, BP-Pt@PNA exhibited cytotoxic enhancement on 4T1 cells. By the synergistic effect of BP and cisplatin, BP-Pt@PNA achieved RF-stimulated systemic immune effect, thus induced enhance suppression on tumor growth and metastasis. Moreover, BP-Pt@PNA realized long-term drug retention in tumor and favorable embolization to tumor-feeding arteries. With high drug loading capacity and favorable bio-safety and bio-degradability, BP-Pt@PNA is expected as an ideal RFNP for precisely synergizing RFA with other antitumor modes in clinical application.

Evaluation of electric field (E) exposure levels and its relationship with the sleep quality of residents around the BTS antennas in Sabzevar, Iran.

Mobile devices and base transceiver station (BTS) are the main sources of human exposure to radio frequency electromagnetic fields (RF-EMFs). Therefore, the aim of the present study was to evaluate the levels of exposure to RF-EMF in three different time intervals and three different distances from BTS antennas in Sabzevar. Additional goals were to investigate the electric field (E) difference between different microenvironments, between the suburbs and downtown, and evaluating the sleep quality of residents around BTS antennas at different distances. The results showed significant differences between the values of E Avg and E max Avg at different times (T1, T2, and T3), different distances (50, 100, and 300 m) from BTS antennas, and between BTS antennas located in the suburbs and downtown. No significant differences were observed between the values of E Avg and E max Avg in terms of microenvironments. Poor sleep quality (>5) was recorded in the residents around the BTS antennas at different distances, and a significant difference was observed between the sleep quality of the residents at a distance of ˂100 m compared to the residents at a distance of ˃300 m. The recorded levels of E in all places and times were below the human safety limits set by the Iranian National Standardization Organization, the Information and Communication Technologies Authority and the International Commission on Non-Ionizing Radiation Protection, indicating the absence of potential risk due to exposure to E in the study area.

PETcoil: first results from a second-generation RF-penetrable TOF-PET brain insert for simultaneous PET/MRI.

Simultaneous positron emission tomography (PET)/magnetic resonance imaging provides concurrent information about anatomic, functional, and molecular changes in disease. We are developing a second generation MR-compatible RF-penetrable TOF-PET insert. The insert has a smaller scintillation crystal size and ring diameter compared to clinical whole-body PET scanners, resulting in higher spatial resolution and sensitivity. This paper reports the initial system performance of this full-ring PET insert. The global photopeak energy resolution and global coincidence time resolution, 11.74 ± 0.03 % FWHM and 238.1 ± 0.5 ps FWHM, respectively, are preserved as we scaled up the system to a full ring comprising 12, 288 LYSO-SiPM channels (crystal size: 3.2 × 3.2 × 20 mm3). Throughout a ten-hour experiment, the system performance remained stable, exhibiting a less than 1% change in all measured parameters. In a resolution phantom study, the system successfully resolved all 2.8 mm diameter rods, achieving an average VPR of 0.28 ± 0.08 without TOF and 0.24 ± 0.07 with TOF applied. Moreover, the implementation of TOF in the Hoffman phantom study also enhanced image quality. Initial MR compatibility studies of the full PET ring were performed with it unpowered as a milestone to focus on looking for material and geometry-related artifacts. During all MR studies, the MR body coil functioned as both the transmit and receive coil, and no observable artifacts were detected. As expected, using the body coil also as the RF receiver, MR image signal-to-noise ratio exhibited degradation (∼30%), so we are developing a high quality receive-only coil that resides inside the PET ring.

Application of radio frequency energy in processing of fruit and vegetable products.

Thermal processing is commonly employed to ensure the quality and extend the shelf-life of fruits and vegetables. Radio frequency (RF) heating has been used as a promising alternative treatment to replace conventional thermal processing methods with advantages of rapid, volumetric, and deep penetration heating characteristics. This article provides comprehensive information regarding RF heating uniformity and applications in processing of fruit and vegetable products, including disinfestation, blanching, drying, and pasteurization. The dielectric properties of fruits and vegetables and their products have also been summarized. In addition, recommendations for future research on RF heating are proposed to enhance practical applications for fruits and vegetables processing in future.

Thermal and Nonthermal Effects of 5 G Radio-Waves on Human's Tissue.

The deployment of 5 G wireless technology has generated considerable interest and debate regarding its potential effects on human health. This work provides a comprehensive overview of the current scientific understanding of the potential health implications associated with 5 G technology. Drawing upon a wide range of research studies, reviews, and expert opinions, we explore the implications through which 5 G signals interact with the human body. This work presents a balanced perspective, summarizing both the potential benefits of 5 G technology, such as improved data transfer speeds, reduced latency, and enhanced connectivity, as well as concerns that have been raised about its effects on human's tissues. We discuss various aspects of health impacts, including thermal and nonthermal effects, focusing on the existing research on radiofrequency electromagnetic fields and their potential to cause adverse health outcomes. Simulation results show the negative effect of radio waves on human's tissues.

Effect of sequential delivery of 1- and 2-MHz bipolar microneedling radiofrequency energy on thermal tissue reactions in a minipig model.

BACKGROUND: Bipolar microneedling radiofrequency (RF) treatment generates different patterns of thermal reactions, depending on the skin impedance and RF treatment parameters, including the frequency, power, conduction time, settings of sub-pulse packs, and penetrating depth and type of microneedles used. We compared the effect of sequential delivery of 1- and 2-MHz bipolar RF energy to in vivo minipig skin on thermal tissue reaction. METHODS: RF treatments at frequencies of 1 and 2 MHz were sequentially delivered to minipigs' skin in vivo. A histological study was performed to analyze RF-induced skin reactions at 1-h and at 3-, 7-, and 14-days post-treatment. RESULTS: The skin specimens demonstrated that the two different frequencies of RF treatment generated mixed patterns of the peri-electrode coagulative necrosis (PECN) according to the experimental settings and tissue impedance. In the PECN zone, the tissue coagulation induced by the first RF treatment was surrounded by the effect of the later RF treatment at the other RF frequency. In the inter-electrode non-necrotic thermal reaction zone, the effect of the latter RF treatment was widespread and deep through the dermis, which had received RF treatment at the other frequency first. The delivery of pulsed-type RF energy at sub-pulse packs of 6 or 10 provided effective RF delivery over long conduction time without excessive thermal damage of the epidermis. Nonetheless, by sequential delivery of two different RF frequencies, RF-induced tissue reactions were found to be markedly enhanced. CONCLUSION: The sequential delivery of 1- and 2-MHz RF energy induces novel histological patterns of tissue reactions, which can synergistically enhance the thermostimulatory effects of each RF setting. Moreover, variations in patterns of tissue reactions can be generated by regulating the order of frequencies and the number of sub-pulse packs of RF used.

Mechanically Adjustable 4-Channel RF Transceiver Coil Array for Rat Brain Imaging in a Whole-Body 7 T MR Scanner.

Investigations of human brain disorders are frequently conducted in rodent models using magnetic resonance imaging. Due to the small specimen size and the increase in signal-to-noise ratio with the static magnetic field strength, dedicated small-bore animal scanners can be used to acquire high-resolution data. Ultra-high-field (≥7 T) whole-body human scanners are increasingly available, and they can also be used for animal investigations. Dedicated sensors, in this case, radiofrequency coils, are required to achieve sufficient sensitivity for the high spatial resolution needed for imaging small anatomical structures. In this work, a four-channel transceiver coil array for rat brain imaging at 7 T is presented, which can be adjusted for use on a wide range of differently sized rats, from infants to large adults. Three suitable array designs (with two to four elements covering the whole rat brain) were compared using full-wave 3D electromagnetic simulation. An optimized static B1+ shim was derived to maximize B1+ in the rat brain for both small and big rats. The design, together with a 3D-printed adjustable coil housing, was tested and validated in ex vivo rat bench and MRI measurements.

Numerical simulation in magnetic resonance imaging radiofrequency dosimetry.

Magnetic Resonance Imaging (MRI) employs a radiofrequency electromagnetic field to create pictures on a computer. The prospective biological consequences of exposure to radiofrequency electromagnetic fields (RF EMFs) have not yet been demonstrated, and there is not enough evidence on biological hazards to offer a definite response concerning possible RF health dangers. Therefore, it is crucial to research the health concerns in reaction to RF EMFs, considering the entire exposure in terms of patients receiving MRI. Monitoring increases in temperaturein-vivothroughout MRI scan is extremely invasive and has resulted in a rise in the utilization of computational methods to estimate distributions of temperatures. The purpose of this study is to estimate the absorbed power of the brain exposed to RF in patients undergoing brain MRI scan. A three-dimensional Penne's bio-heat equation was modified to computationally analyze the temperature distributions and potential thermal effects within the brain during MRI scans in the 0.3 T to 1.5 T range (12.77 MHz to 63.87 MHz). The instantaneous temperature distributions of thein-vivotissue in the brain temperatures measured at a time, t = 20.62 s is 0.2 °C and t = 30.92 s is 0.4 °C, while the highest temperatures recorded at 1.03 min and 2.06 min were 0.4 °C and 0.6 °C accordingly. From the temperature distributions of thein-vivotissue in the brain temperatures measured, there is heat build-up in patients who are exposed to electromagnetic frequency ranges, and, consequently, temperature increases within patients are difficult to prevent. The study has, however, indicated that lengthier imaging duration appears to be related to increasing body temperature.

A Systematic Review on the In Vivo Studies on Radiofrequency (100 kHz-300 GHz) Electromagnetic Field Exposure and Co-Carcinogenesis.

In this systematic review, the potential role of in vivo RF-EMF exposure combined with the administration of well-known carcinogens in tumor promotion/progression is assessed. A total of 25 papers were included in the review. Each paper was assessed for Risk of Bias and for the attribution of the quality category. A meta-analysis was conducted on 18 studies, analyzing data for nine different organs/tumors to assess the potential increased risk for the onset of tumors as well as the effects on survival. A descriptive review was performed for the remaining seven eligible papers. In most cases, the results of the meta-analysis did not reveal a statistically significant difference in tumor onset between the sham and co-exposed samples. There was a numerically small increase in the risk of malignant tumors observed in the kidney and liver, as well as benign lung tumors. The level of evidence for health effects indicated "inadequate" evidence for an association between in vivo co-exposure to RF-EMF and known carcinogens and the onset of malignant or benign tumors in most of the analyzed tissues. Nevertheless, the limited number of eligible papers/studies for most of the analyzed tissues suggests that these results cannot be considered definitively conclusive.