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Effects of radiofrequency electromagnetic field (RF-EMF) exposure on male fertility: A systematic review of experimental studies on non-human mammals and human sperm in vitro
Get PDFBackground: The World Health Organization is coordinating an international project aimed at systematically reviewing the evidence regarding the association between radiofrequency electromagnetic field (RF-EMF) exposure and adverse health effects. Reproductive health outcomes have been identified among the priority topics to be addressed. Objectives: To evaluate the effect of RF-EMF exposure on male fertility of experimental mammals and on human sperm exposed in vitro. Methods: Three electronic databases (PubMed, Scopus and EMF Portal) were last searched on September 17, 2022. Two independent reviewers screened the studies, which were considered eligible if met the following criteria: 1) Peer-reviewed publications of sham controlled experimental studies, 2) Non-human male mammals exposed at any stage of development or human sperm exposed in vitro, 3) RF-EMF exposure within the frequency range of 100 kHz-300 GHz, including electromagnetic pulses (EMP), 4) one of the following indicators of reproductive system impairment: • decrease of fertility: rate of infertile males, rate of nonpregnant females, litter size and in vitro fertilization rate; • effects on semen quality: in animal studies sperm count, in both animal and in vitro studies sperm vitality, morphology and DNA/chromatin alterations; • reproductive organ toxicity: testis-epididymis weight, testis or epididymis histology, testis histomorphometry, testicular cell death, estimated testicular cell production; • hormonal effects: testosterone level.Two reviewers extracted study characteristics and outcome data. We assessed risk of bias (RoB) using the Office of Health Assessment and Translation (OHAT) guidelines. We categorized studies into 3 levels of overall RoB: low, some or high concern. We pooled study results in a random effects meta-analysis comparing average exposure to no-exposure and in a dose–response meta-analysis using all exposure doses. For experimental animal studies, we conducted subgroup analyses for species, Specific Absorption Rate (SAR) and temperature increase. We grouped studies on human sperm exposed in vitro by the fertility status of sample donors and SAR. We assessed the certainty of the evidence using the GRADE approach after excluding studies that were rated as “high concern” for RoB. Results: One-hundred and seventeen papers on animal studies and 10 papers on human sperm exposed in vitro were included in this review. Only few studies were rated as “low concern” because most studies were at RoB for exposure and/or outcome assessment. Subgrouping the experimental animal studies by species, SAR, and temperature increase partly accounted for the heterogeneity of individual studies in about one third of the meta-analyses. In no case was it possible to conduct a subgroup analysis of the few human sperm in vitro studies because there were always 1 or more groups including less than 3 studies. Among all the considered endpoints, the meta-analyses of animal studies provided evidence of adverse effects of RF-EMF exposure in all cases but the rate of infertile males and the size of the sired litters. The assessment of certainty according to the GRADE methodology assigned a moderate certainty to the reduction of pregnancy rate and to the evidence of no-effect on litter size, a low certainty to the reduction of sperm count, and a very low certainty to all the other meta-analysis results. Studies on human sperm exposed in vitro indicated a small detrimental effect of RF-EMF exposure on vitality and no-effect on DNA/chromatin alterations. According to GRADE, a very low certainty was attributed to these results. The few studies that used EMP exposure did not show effects on the outcomes. A low to very low certainty was attributed to these results. Discussion: Many of the studies examined suffered of severe limitations that led to the attribution of uncertainty to the results of the meta-analyses and did not allow to draw firm conclusions on most of the endpoints. Nevertheless, the associations between RF-EMF exposure and decrease of pregnancy rate and sperm count, to which moderate and low certainty were attributed, are not negligible, also in view of the indications that in Western countries human male fertility potential seems to be progressively declining. It was beyond the scope of our systematic review to determine the shape of the dose–response relationship or to identify a minimum effective exposure level. The subgroup and the dose–response fitting analyses did not show a consistent relationship between the exposure levels and the observed effects. Notably, most studies evaluated RF-EMF exposure levels that were higher than the levels to which human populations are typically exposed, and the limits set in international guidelines. For these reasons we cannot provide suggestions to confirm or reconsider current human exposure limits. Considering the outcomes of this systematic review and taking into account the limitations found in several of the studies, we suggest that further investigations with better characterization of exposure and dosimetry including several exposure levels and blinded outcome assessment were conducted. Protocol registration: Protocols for the systematic reviews of animal studies and of human sperm in vitro studies were published in Pacchierotti et al., 2021. The former was also registered in PROSPERO (CRD42021227729 https://www.crd.york.ac.uk/prospero/display_record.php?RecordID = 227729) and the latter in Open Science Framework (OSF Registration DOI https://doi.org/10.17605/OSF.IO/7MUS3)
Unveiling the transport properties of protic ionic liquids: Lithium ion dynamics modulated by the anion fluorine reservoir
No full textProtic ionic liquids (PILs) show great potential as electrolyte components for energy storage devices. A comprehensive understanding of their transport properties must be achieved to optimize the design of safer and efficient electrolytes. This study focuses on a series of PILs based on the DBUH+ cation (protonated 1,8-diazabicyclo[5,4,0]‐undec-7-ene superbase) and three anions derived from strong acids: TFO− (triflate), IM14− (perfluorobutyl-trifluoromethylsulfonylimide) and TFSI− (bis(trifluoromethylsulfonyl)imide). Neat PILs and PILs doped with LiTFO, LiIM14, and LiTFSI were studied using temperature-dependent NMR diffusion and relaxation techniques. The ionicity of these systems was also evaluated. Results revealed that the dynamic behaviour of lithium ions, as well as ionicity, strongly depend on the structural features of the anions, particularly in the case of IM14−, whose main feature is the uneven distribution of the fluorinated sidegroups. The 19F relaxation rates in IM14− provide insights into the rotational reorientation of that anion. DBUH-IM14 exhibited diffusion coefficients lower than the expected ones on the basis of its viscosity, likely due to fluorophilic intermolecular interactions involving the fluorinated terminal groups. The presence of Li+ in the DBUH-IM14 electrolyte led to unexpected and relatively faster translational mobility of Li+ ions, resulting in a higher lithium apparent transference number. However, the trends observed in ionicity indicate a more complex interplay between intermolecular interactions and ion correlations. While DBUH-TFSI showed minimal effect of Li+ addition, DBUH-TFO and DBUH-IM14 exhibited a significant decrease in ionicity, possibly attributed to strong interactions between ions
Upgraded Three-Wavelength Lidar for Real-Time Observations of Volcanic Aerosol Optical and Microphysical Properties at Etna (Italy): Calibration Procedures and Measurement Tests
No full textAn innovative mobile lidar device, developed to monitor volcanic plumes during explosive eruptions at Mt. Etna (Italy) and to analyse the optical properties of volcanic particles, was upgraded in October 2023 with the aim of improving volcanic plume retrievals. The new configuration of the lidar allows it to obtain new data on both the optical and the microphysical properties of the atmospheric aerosol. In fact, after the upgrade, the lidar is able to measure three backscattering coefficients, two extinction coefficients and two depolarisation ratios in a configuration defined as “state-of-the-art lidar”, where properties such as particle size distribution and the refractive index can be derived. During the lidar implementation, we were able to test the system’s performance through specific calibration measurements. A comparison in an aerosol-free region (7.2–12 km) between lidar signals at 1064 nm, 532 nm and 355 nm and the corresponding pure molecular profiles showed a relative difference of <1% between them for all the wavelengths, highlighting the good dynamic of the signals. The overlap correction allowed us to reduce the underestimation of the backscattering coefficient from 50% to 10% below 450 m and 750 m at both 355 and 532 nm, respectively. The correct alignment between the laser beam and the receiver optical chain was tested using the signal received from the different quadrants of the telescope, and the relative differences between the four directions were comparable to zero, within the margin of error. Finally, the first measurement results are shown and compared with results obtained by other instruments, with the aim of proving the ability of the upgraded system to more precisely characterise aerosol optical and microphysical properties
Qualification Activities for the DTT Divertor
No full textThe divertor tokamak test (DTT) facility is currently in the design stage and in the initial phase of construction at the research center ENEA Frascati. The DTT facility aims at searching integrated solutions for the power exhaust issue maintaining plasma performances compatible with future fusion devices. For this reason, the first DTT divertor was designed to accommodate different magnetic configurations: in particular other than single null (SN), the compatibility with X-divertor (XD) and negative triangularity (NT) with different leg lengths was ensured. To accommodate the strike point positions of the different magnetic equilibria, all plasma facing surfaces (i.e., inner and outer vertical targets, as well as the dome) have to be entirely made of tungsten (W) monoblocks. At the same time, to leave more space to the divertor legs, it was decided to design a dome with a flat shape. These two factors along with the armor with W monoblock and the flat shape have required finding ad hoc technological solutions for the plasma facing units (PFUs) of the dome with the need of a research and qualification phase. Above all, a W flat tiles (FTs) design was required at the inner dome end, where the copper cooling pipes turn by 90°. The FT segment covers only a small length of the PFU (40 mm), and the goal is to join both monoblock and FT segments to the pipe in a single manufacturing process. The technique used is the hot radial pressing (HRP), which has been developed in ENEA and qualified for the manufacturing of the ITER inner vertical target
Numerical investigation of toroidal plasma response for ELM control via magnetic perturbations in the DTT Tokamak
No full textLinear plasma response modeling is exploited in this work to assess the effect of different coil configurations on edge localized mode (ELM) stability in full power operational scenarios for the Divertor Tokamak Test (DTT) facility, presently under construction at the ENEA site of Frascati (Italy). The MARS-F code is used to compute, in toroidal geometry and including flow, the resistive plasma response to different vacuum fields with toroidal mode numbers n = 1 , 2 , 3 . Peeling-like response in particular, correlated with ELM control, is found to be significant for n = 2 , 3 perturbations while n = 1 induces a large core response in the investigated scenarios. Two metrics are used to link plasma response to ELM control. Namely the local normal plasma displacement in the x-point region and the Chirikov parameter in PEST-like straight-field-line coordinates. These criteria are used to predict optimal phasing of the active coil arrays and current thresholds based on empirical evidence. Depending on the number of active coils and on the scenario, coil currents between 20 and 40 kAt are predicted to be effective for ELM mitigation in DTT
Pinning Properties of 1144 Polycrystalline Samples With Aliovalent Doping
No full textThe 1144 Iron-Based Superconductors (IBSC), characterized by the A1AE1Fe4As4 chemical composition (A = Alkaline, AE = Alkaline-Earth), has gained significant interest in the recent years due to their crystalline structure characterized by an intrinsic modulation of the strain along the c-axis and by the proneness in forming crystalline defects with a positive impact on flux pinning. Moreover, it has been proved that the compound is compatible with the cost-effective powder-in-tube (PIT) manufacturing process. In our recent experiments, we have showed that the A1AE1Fe4As4 structure can be tailored to obtain a 1144 compound characterized by different (AxAE1-x)(AEyA1-y)Fe4As4 chemical formulae without any depression in the critical temperature value. On the other hand, it has been recently shown that the doping with selected elements on both A and AE sites has a clear influence on the pinning and the grain boundary properties of poly-crystalline samples. In this work we report the results of the extensive magnetic characterization performed on pristine Ca1K1Fe4As4 and doped (AxCa1-x)(AEyK1-y)Fe4As4 with Ba as dopant on the K site and either La or Na as dopant on the Ca site. In particular, the magnetization hysteresis loops recorded at different temperatures M(H, T) and the critical current density dependences extracted from the M(H) using the Bean model, Jc(B, T), have been analyzed in order to assess the effect of aliovalent doping on the quality of the produced samples in terms of grain boundary properties and pinning efficiency
Composition and Injection Angle Effects on Combustion of an NH3/H2/N2 Jet in an Air Crossflow
Get PDFThis study explores the combined effects of fuel composition and injection angle on the combustion behavior of an (Formula presented.) jet in an air crossflow by means of high-fidelity Large Eddy Simulations (LESs). Four distinct fuel mixtures derived from ammonia partial decomposition, with hydrogen concentrations ranging from 15% to 60% by volume, are injected at angles of 90 (Formula presented.) and 75 (Formula presented.) relative to the crossflow, and at operating conditions frequently encountered in micro-gas turbines. The influence of strain on peak flame temperature and NO formation in non-premixed, counter-flow laminar flames is first examined. Then, the instantaneous flow features of each configuration are analyzed focusing on key turbulent structures, and time-averaged spatial distributions of temperature and NO in the reacting region are provided. In addition, statistical analysis on the formation pathways of NO and (Formula presented.) is performed, revealing unexpected trends: in particular, the lowest hydrogen content flame yields higher temperatures and NO production due to the enhancement of the ammonia-to-hydrogen conversion chemical mechanism, thus promoting flame stability. As the hydrogen concentration increases, this conversion decreases, leading to lower NO emissions and unburned fuel, particularly at the 75 (Formula presented.) injection angle. Flames with a 90 (Formula presented.) injection angle exhibit a more pronounced high-temperature recirculation zone, further driving NO production compared with the 75 (Formula presented.) cases. These findings provide valuable insights into optimizing ammonia–hydrogen fuel blends for high-efficiency, low-emission combustion in gas turbines and other applications, highlighting the need for a careful balance between fuel composition and injection angle
Evaluation of carbon sink and photovoltaic system carbon reduction along roadside space
No full textAs China's photovoltaic (PV) sector experiences rapid growth, the availability of land resources has become a pivotal policy focus, driving the need for comprehensive research and strategic planning for roadside PV initiatives. Utilizing a fuzzy multi-criteria decision-making approach, combined with GIS spatial analysis and a modular design framework, our study quantitatively compared the carbon reduction capabilities of PV systems against the carbon sequestration potential of various vegetative arrangements along the roadside space. The roadside space analysis modular considers a range of factors including topography, meteorology, and construction costs. We examined the spatial distribution of suitability for PV installation and vegetation establishment along the provincial expressway network in China. The results revealed that Inner Mongolia stood out as the frontrunner in carbon reduction potential within high-suitability zones for PV construction, achieving an impressive 4.845 million tons of carbon reduction—nearly four times greater than that of Shaanxi Province. In contrast, the carbon sequestration attributed to vegetation greening in areas less suited for PV development revealed a higher propensity in the southeastern provinces. Guangdong led the charge with an impressive annual carbon sequestration of 2.89 million tons. This was closely followed by Yunnan, Sichuan, Hebei, Guizhou, and Henan, each achieving carbon sequestration amounts exceeding 2 million tons. These results offer valuable quantitative support and practical recommendations for achieving low-carbon objectives in the construction of China's expressways
A Note on Exact Results for Burgers-like Equations Involving Laguerre Derivatives
No full textIn this work, we consider some Burgers-like equations involving Laguerre derivatives and demonstrate that it is possible to construct specific exact solutions using separation of variables. We prove that a general scheme exists for constructing exact solutions for these Burgers-like equations and extending to more general cases, including nonlinear time-fractional equations. Exact solutions can also be obtained for KDV-like equations involving Laguerre derivatives. We finally consider a particular class of Burgers equations with variable coefficients whose solutions can be obtained similarly
Trace contaminants in biogas: Biomass sources, variability and implications for technology applications
Get PDFBiogas represents a renewable and controllable energy source. Although predominantly composed of methane and carbon dioxide, it also contains various trace contaminants that can be detrimental to the technologies used for its conversion. The aim of this work is to comprehensively explore trace contaminants in biogas. The assessment employs a two-level approach: an extensive literature review on biogas trace contaminants, complemented with on-site analyses from real-scale biogas plants to enhance and validate the literature findings. The biogas contaminants – sulphur compounds, siloxanes, halocarbons and aromatic compounds – are quantified and categorised into four distinct groups: landfill gas, agricultural gas, gas derived from the organic fraction of municipal solid waste (OFMSW), and gas from wastewater (WWTP). This study also provides contaminant effects and required thresholds for different biogas conversion technologies, including internal combustion engines, upgrading to biomethane, and innovative solid oxide fuel cells (SOFCs). The two-level analysis reveals significant variability in contaminant levels across different biogas sources, with H2S being the most prevalent contaminant, averaging between 181 (WWTP) and 901 ppm (landfill gas). Other sulphur compounds show the highest average concentration in biogas from OFMSW (98 ppm), followed by agricultural and landfill gases. Siloxanes are typically more abundant in biogas from WWTP (2.55 ppm), while landfill gas exhibits the highest average concentrations of halocarbons and aromatic compounds (6 ppm and 109 ppm, respectively). Moreover, this study highlights the need for in-depth measurements of contaminants for highly sensitive technologies, such as SOFCs, to properly design tailored contaminant removal solutions