High Electromagnetic Field Research Articles

Evaluation of the efficacy of the combination of high intensity electromagnetic field and radiofrequency in promoting lipolysis

Introduction: The organization of skeletal muscle is complex, structured in distinct layers. This organization allows skeletal muscles to respond to electrical stimuli with precise and coordinated contractions. Muscle contraction occurs through responses to electrical stimuli sent by the brain to the motor neurons in the muscle fiber, these stimuli can also be induced by technologies, one of which is the high intensity electromagnetic field, also known as the HIFEM current, leading to contractions considered to be supramaximal that cannot be achieved with normal contraction, resulting in muscle hypertrophy. Objective: This study aims to analyze the results of the combination of these technologies to reduce adipose tissue. Methods: This is a clinical, observational, cross-sectional study investigating the effectiveness of the combination of high-intensity electromagnetic field and radiofrequency technologies. The sample consisted of 6 volunteers. Conclusion: It is concluded that the combination of muscle contraction and radiofrequency technologies represents an innovative approach to fat burning, combining the efficiency of lipolysis promoted by muscle energy demand with the thermal effect of radiofrequency, reducing the thickness of the fat layer by 19.53%.

A rapid method for prediction of the non-resonant ultra-fast multipactor regime in high gradient RF accelerating structures

The purpose of this work is to present an analytical method that allows to estimate in an approximate and fast way the presence of the non-resonant and ultra-fast multipactor effect in RF accelerating structures in the presence of high gradient electromagnetic fields. This single-surface multipactor regime, which has been little studied in the scientific literature, is characterised by appearing only under conditions of very strong RF electric fields (of the order of tens or hundreds of MV/m), where it is predominant over other types of single- or dual-surface resonance described in classical multipactor theory. This type of multipactor causes a rapid growth of the electron population and poses a serious drawback in the operation of RF accelerator components operating under high gradient conditions. Specifically, in dielectric-assist accelerating structures (DAA) it has been experimentally found that the presence of multipactor limits the maximum operating gradient of these components due to a significant increase in the reflected power due to the discharge, being this phenomenon the main problem to overcome. In a previous work, we found and described in detail by means of numerical simulations the presence of this non-resonant and ultra-fast multipactor regime in a DAA structure design for hadrontherapy. Here we aim to present a simple and fast method to predict the presence of this non-resonant and ultra-fast multipactor regime in RF accelerator structures with cylindrical revolution symmetry around the acceleration axis. This method is especially useful in the design stages of accelerating structures as it provides much faster results than numerical simulations of the multipactor, with quite good accuracy in a wide range of cases as shown in this paper.

Optical trapping of nanoparticles using all-dielectric quasi-bound states in the continuum

Plasmonic nanotweezers employing metallic nanostrctures provide a powerful tool for optical trapping of nanoscale objects; however, they are limited by strong heating effects resulting from the intrinsic loss in metallic materials. Alternatively, quasi-bound states in the continuum (q-BICs), supported in all-dielectric metasurfaces, offer a higher quality-factor (Q-factor) and electric field enhancement compared to plasmonic systems, making it a promising candidate for heatless nanotweezers with high performance. Here, we demonstrate an all-dielectric nanotweezer harnessing q-BIC for effective trapping of nanoparticles with low trapping power and negligible heating effects. The quasi-BIC system provides very high electromagnetic field intensity enhancement as well as high-quality-factor resonances. The q-BIC mode is induced by symmetry breaking of periodic double ring nanostructure, which leads to an increased optical force and potential energy in comparison to prior studies, enabling attractive promise in subwavelength particle trapping applications. Moreover, the q-BIC nanotweezer creates numerous optical hotspots characterized by significant field confinement and enhancement, generating multiple trapping sites and thus facilitating high-throughput trapping of nanoscale objects. Furthermore, the trapping wavelength (1047.59 nm) in our structure exactly corresponds with the current laser choice for working with biological samples. In addition, we show that trapped particles can improve the resonance mode of the cavity in a symmetry-broken system, which in turn enhances the trapping process. Our study paves the way for applying q-BIC systems to low-power particle trapping and sensing applications, especially for parallel analyses of biological cells and protein molecules.

Flexible SERS substrates with gradient porous Cu structure dealloying from the thermal diffusion couples of Al/Cu stacking foils

Accurate and sensitive surface-enhanced Raman scattering (SERS) substrates are urgently demanded for the various analytic techniques. The SERS substrates with multimodal and gradient porous structure, utilized for the Rhodamine 6G (R6G) detection, have been designed and successfully fabricated from the thermal diffusion couples of Al and Cu foils via chemical dealloying. The structural inheritance of the initial microstructure of thermal diffusion couple precursors governs the formation of the final layer-by-layer gradient porous Cu with different characteristic pore sizes and morphology. An outmost surface layer of disordered lipstick-like porous structure on the SERS substrates enhances SERS effects as has been expected. The SERS activity of R6G Raman probes on gradient porous Cu is evaluated as a SERS enhancement factor of 6.63 × 1012 and limit of detection of 2.10 × 10−17 mol/L, higher than other porous SERS substrates. Meanwhile, the present SERS substrates are flexible and exhibit good bending properties due to the unreacted Cu layer as a supporting skeleton and other gradient porous Cu layers. The superior SERS performances are considered to result from the synergetic effects of the surface scattering of porous Cu rods and enhancements of the high electromagnetic fields between the small gaps between the nanopores.

Experimental investigation of electromagnetic interference impact on phase change material coated solar photovoltaic panel

ABSTRACT High Voltage Transmission Line Electromagnetic Field’s (HVTL-EMF) impact on solar PV performance is analyzed in the proposed work. Depending on HV-EMF, the electrical characteristics and conversion process of PhotoVoltaic (PV) panels are analyzed. Electromagnetic (EM) field from HV lines has a partially positive and somewhat negative impact on solar PV. When absorption probability is low, one photon and one phonon are required. Phonons are vibrational energy units. A solar PV cell made of Silicon (Si) semiconductor material requires phonons to have high conversion efficiency and electric field from HV transmission line induces phonon. In addition, electric field from HV line increases the solar cell temperature (10 to 15°C) to the ambient temperature. Because of high solar PV cell temperature and high EM field, solar PV power generation is affected by increasing panel temperature. The proposed system uses unnatural Phase Change Material (PCM-Glauber salt (Na2SO4.10 H2O)) coated to the backside of solar PV to normalize the temperature. The impact of electromagnetic fields produced by HV lines on solar cells coated with PCM is validated with experimental testing results. The experiment considers a HVTL of 230kV and solar PV rating of 20 W. The experimental results are measured at various distance ranging from 12 to 22 meters between solar PV and HV transmission lines. Conversion efficiency of solar PV with PCM coating under the impact of HVTL- EMF has increased by 3%.

Periodic Folded Gold Nanostructures with a Sub-10 nm Nanogap for Surface-Enhanced Raman Spectroscopy.

Surface-enhanced Raman spectroscopy has emerged as a powerful spectroscopy technique for detection with its capacity for label-free, nondestructive analysis, and ultrasensitive characterization. High-performance surface-enhanced Raman scattering (SERS) substrates with homogeneity and low cost are the key factors in chemical and biomedical analysis. In this study, we propose the technique of atomic force microscopy (AFM) scratching and nanoskiving to prepare periodic folded gold (Au) nanostructures as SERS substrates. Initially, folded Au nanostructures with tunable nanogaps and periodic structures are created through the scratching of Au films by AFM, the deposition of Ag/Au films, and the cutting of epoxy resin, reducing fabrication cost and operational complexity. Periodic folded Au nanostructures show the three-dimensional nanofocusing effect, hotspot effect, and standing wave effect to generate an extremely high electromagnetic field. As a typical molecule to be tested, p-aminothiophenol has the lowest detection limit of up to 10-9 M, owing to the balance between the electromagnetic field energy concentration and the transmission loss in periodic folded Au nanostructures. Finally, by precisely controlling the periods and nanogap widths of the folded Au nanostructures, the synergistic effect of surface plasmon resonance is optimized and shows good SERS properties, providing a new strategy for the preparation of plasmonic nanostructures.

Evaluation of custom-designed lateral power transistors in a silicon-on-insulator process in a synchronous buck converter

Most of todays power converters are based on power semiconductors, which are built in vertical power semiconductor processes. These devices result in limited packaging possibilities, which lead to physically long galvanic connections and therefore high external electromagnetic fields. These fields compromise power quality significantly. Therefore this paper examines the possibility to use lateral silicon-on-insulator power MOSFETs and uses the custom-made devices in a 48 V to 12 V synchronous buck converter in continuous conduction mode. The converter is designed based on custom made power transistors, implemented and verified by experimental results. The resulting efficiency of the 1 Wconverter is around 93 % across a wide load range and its temperature rise is less the 10 C. This leads to the conclusion, that modern lateral silicon-on-insulator power processes allow high integration of power stages and therefore promise lower emissions, leading to higher power quality.

Ultra‐Fast Pulsed Discharge Preparation of Coordinatively Unsaturated Asymmetric Copper Single‐Atom Catalysts for CO2 Reduction

AbstractSingle‐atom catalysts possess great potential for applications in electrochemical carbon dioxide reduction reactions. Recently, the fast and low‐cost preparation of highly efficient single‐atom catalysts remains a challenge. Herein, a high‐density current generated by pulsed discharge is employed for the formation of graphene aerogel anchored Cu single atom catalysts perfectly. The Cu atoms decomposed by Cu(NO3)2•xH2O are fixed on graphene under the local transient high temperature and intense electromagnetic field. The activity and selectivity of formic acid are correlated with the coordinatively unsaturated Cu─N1O1 moieties, reaching an optimal Faradaic efficiency (93.7%) at −0.9 V versus a reversible hydrogen electrode (RHE). In situ characterizations reveal that the asymmetric Cu─N/O structure in a pinched state displays better catalytic activity in CO2RR. Density functional theory results indicate that the Cu─N1O1 sites regulate the adsorption configuration of intermediates and lower the energy barrier for the hydrogenation of *OCHO species, thereby promoting CO2‐to‐HCOOH conversion.

Physicochemical, electrochemical, and biological characterization of field assisted gold nanocluster-coated barium titanate nanoparticles for biomedical applications.

Fluorescence-based bioimaging is an imperative approach with high clinical relevance in healthcare applications and biomedical research. The field of bioimaging plays an indispensable role in gaining insight into the internal architecture of cells/tissues and comprehending the physiological functions associated with biological systems. With the utility of piezoelectric nanomaterials, the bioelectric interface has been significantly investigated, leading to remarkable clinical relevance. Herein, we have developed barium titanate nanoparticle (BT) coated gold nanoclusters (AuNCs) in the presence and absence of an electromagnetic field (EMF). In this work, the effect of low (0.6 G) and high (2.0 G) EMFs on the structural arrangement of these piezoelectric nanocomposites (ABT) has been extensively studied with the help of X-ray diffraction (XRD), high diffraction resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Furthermore, the two derivatives of ABT i.e. 0.6 ABT and 2.0 ABT have been evaluated for electrochemical behavior for their applicability as a candidate for exploring the bioelectric interface. Additionally, ABT, 0.6 ABT, and 2.0 ABT have been explored for cytocompatibility and bioimaging applications. The proposed piezoelectric nanocomposite, as a multifunctional platform, has enormous proficiency in the field of bioimaging and the capability to be utilized across the bioelectric interface.

Single and combined neurotoxic, cytotoxic and genotoxic effects of 5GHz MIMO waves and computed tomography irradiation in male Wistar rats

ABSTRACT A significant public concern is how technologies that emit electromagnetic waves interact and affect the biota because they are linked to the dysregulation of genes involved in neurotransmission, oxidative stress, and normal cellular function. Standard methods have been used to study how the combination of electromagnetic waves from 5 GHz radio and computed tomography (CT) irradiation affects whole blood parameters, neurobehavioural profiles, genomic DNA, and p53 gene expression in Wistar rats grouped into five, namely, I-Negative control, II-sham, III-5 GHz only, IV-5 GHz + CT, V-CT. The 5 GHz router was connected to the internet using an ethernet cable and the specific absorbance rate (SAR) was measured as 0.54W/kg and 24 V/0.5A power density, while CT parameters were set at 140 K.v, 300 mA, 5.3 cv at a 1.0-s speed for 60 s. Genomic DNA was isolated from rats’ cerebral cortex, while target gene and internal control primers (GAPDH) were synthesized for tumor suppressor (p53) gene expression and electrophoresed on a 1.2% agarose gel. We found that CT irradiation had gross effects on platelets, white blood cell counts, memory, hepatic and testicular histoarchitectures compared to the 5 GHz-only group. However, there was a loss of p53 (exons 5–7) gene bands in electrophoresed data with increased micronucleated polychromatic erythrocyte count in the 5 GHz group. Regardless of the interferential interaction in the combination group, the deleterious effects of non-ionizing and ionizing irradiation in the single and combined exposure groups predict functional abnormalities and dysregulated cellular processes from high electromagnetic fields exposure in biological systems.

High-accuracy calculation of singular electromagnetic fields in regions with re-entrant peripheries

Accurate analysis of the electromagnetic fields inside waveguides and cavities with re-entrant boundaries is crucial for many multi-scale device applications. In earlier approaches, the singularities that exist in electromagnetic field gradients inside such waveguides and cavities significantly reduce the accuracy of the calculations. In our scheme, these singular behaviors are treated using Hermite finite elements combined with analytical regularization of the action integral. We show that this approach provides considerably higher accuracy as compared with other methods employed in the literature. Specific calculations are presented for three typical regions: (a) an L-shaped waveguide, (b) an L-cavity, and (c) a cubic cavity with an octant removed to form a triple-junction corner. The method can be adapted to evaluate very high electromagnetic fields in any complex structures displaying “hot points.”

Superhydrophobic Surface Modification of Polymer Microneedles Enables Fabrication of Multimodal Surface-Enhanced Raman Spectroscopy and Mass Spectrometry Substrates for Synthetic Drug Detection in Blood Plasma.

Microneedles are widely used substrates for various chemical and biological sensing applications utilizing surface-enhanced Raman spectroscopy (SERS), which is indeed a highly sensitive and specific analytical approach. This article reports the fabrication of a nanoparticle (NP)-decorated microneedle substrate that is both a SERS substrate and a substrate-supported electrospray ionization (ssESI) mass spectrometry (MS) sample ionization platform. Polymeric ligand-functionalized gold nanorods (Au NRs) are adsorbed onto superhydrophobic surface-modified polydimethylsiloxane (PDMS) microneedles through the control of various interfacial interactions. We show that the chain length of the polymer ligands dictates the NR adsorption process. Importantly, assembling Au NRs onto the micrometer-diameter needle tips allows the formation of highly concentrated electromagnetic hot spots, which provide the SERS enhancement factor as high as 1.0 × 106. The micrometer-sized area of the microneedle top and high electromagnetic field enhancement of our system can be loosely compared with tip-enhanced Raman spectroscopy, where the apex of a plasmonic NP-functionalized sharp probe produces high-intensity plasmonic hot spots. Utilizing our NR-decorated microneedle substrates, the synthetic drugs fentanyl and alprazolam are analyzed with a subpicomolar limit of detection. Further analysis of drug-molecule interactions on the NR surface utilizing the Langmuir adsorption model suggests that the higher polarizability of fentanyl allows for a stronger interaction with hydrophilic polymer layers on the NR surface. We further demonstrate the translational aspect of the microneedle substrate for both SERS- and ssESI-MS-based detection of these two potent drugs in 10 drug-of-abuse (DOA) patient plasma samples with minimal preanalysis sample preparation steps. Chemometric analysis for the SERS-based detection shows a very good classification between fentanyl, alprazolam, or a mixture thereof in our selected 10 samples. Most importantly, ssESI-MS analysis also successfully identifies fentanyl or alprazolam in these same 10 DOA plasma samples. We believe that our multimodal detection approach presented herein is a highly versatile detection technology that can be applicable to the detection of any analyte type without performing any complicated sample preparation.

Clinical Outcome of specific therapy using high intensity electromagnetic field in Patients with Carpal Tunnel Syndrome

Background: Carpal tunnel syndrome(CTS) is a compressive mononeuropathy affecting approximately 3-6% of the adult population, having a strong physical, psychological, and economic impact on the patient. The high intensity electromagnetic field applied with Super Inductive System (SIS) therapy has effects on pain relief, myorelaxation or miostimulation. The objective of this study is to assess the clinical outcome of patients with CTS after SIS therapy. Material and method: An observational prospective study was conducted between 2021-2022 on a cohort of 56 patients admitted to the Balneal and Rehabilitation Techirghiol Sanatorium for 2 weeks, with specific symptoms of CTS. The patients underwent treatment for two weeks at the sanatorium, receiving three SIS therapy sessions per week with the BTL-6000 device, and also other daily physical therapies. Results: There was a statistically significant difference in the proportion of patients who experienced pain and paresthesia before treatment and the proportion of patients who experienced the same symptoms after treatment p<0.05 respectively p<0.01. Conclusion: The high intensity electromagnetic field using SIS therapy has been proven to be effective and safe in treating patients with CTS, bringing important benefits to patients by relieving pain, and paraesthesia, and improving the quality of life of patients.

Achiral nanoparticle trapping and chiral nanoparticle separating with quasi-BIC metasurface.

Dielectric metasurfaces based on quasi-bound states in the continuum (quasi-BICs) are a promising approach for manipulating light-matter interactions. In this study, we numerically demonstrate the potential of silicon elliptical tetramer dielectric metasurfaces for achirality nanoparticle trapping and chiral nanoparticle separation. We first analyze a symmetric tetramer metasurface, which exhibits dual resonances (P1 and P2) with high electromagnetic field intensity enhancement and a high-quality factor (Q-factor). This metasurface can trap achiral nanoparticles with a maximum optical trapping force of 35 pN for 20 nm particles at an input intensity of 100 mW. We then investigate an asymmetric tetramer metasurface, which can identify and separate enantiomers under the excitation of left-handed circularly polarized (LCP) light. Results show that the chiral optical force can push one enantiomer towards regions of the quasi-BIC system while removing the other. In addition, the proposed asymmetric tetramer metasurface can provide multiple Fano resonances (ranging from R1 to R5) and high trap potential wells of up to 33 kBT. Our results demonstrate that the proposed all-dielectric metasurface has high performance in nanoparticle detection, with potential applications in biology, life science, and applied physics.

Plasmonics: A Versatile Toolbox for Heterogeneous Photocatalysis

Plasmonic photocatalysis is a dynamic field of research devoted to the activation of chemical transformations thanks to the unique optoelectronic features of plasmonic nanomaterials such as their high electromagnetic field enhancements or their ability to generate nonthermalized charge carriers and localized temperature gradients. Importantly, the use of these objects as photocatalysts can lead to new reactivities when compared with classical heterogeneous photocatalysts, including an unprecedented control over efficiency and chemical selectivity within a broader range of the solar spectrum. In the present study, the most important aspects that need to be taken into consideration when designing a plasmonic photocatalytic system are summarized. Representative examples from the literature toward the rational design of the plasmonic photocatalyst are provided, together with a comprehensive list of organic and inorganic transformations that have been successfully modulated by plasmons. The importance of single nanoparticle measurements as a new means to characterize these systems is also discussed, allowing a better insight into single object heterogeneities or structure–function relationships that are usually lost in ensemble characterization techniques. Finally, the major role played by reaction intermediates when performing photoredox processes in solution is highlighted, particularly important when driving photochemical reactions in biological environments.

High-quality factor mid-infrared absorber based on all-dielectric metasurfaces.

The absorption spectrum of metasurface absorbers can be manipulated by changing structures. However, narrowband performance absorbers with high quality factors (Q-factor) are hard to achieve, mainly for the ohmic loss of metal resonators. Here, we propose an all-dielectric metasurface absorber with narrow absorption linewidth in the mid-infrared range. Magnetic quadrupole resonance is excited in the stacked Ge-Si3N4 nanoarrays with an absorption of 89.6% and a Q-factor of 6120 at 6.612 µm. The separate lossless Ge resonator and lossy Si3N4 layer realize high electromagnetic field gain and absorption, respectively. And the proposed method successfully reduced the intrinsic loss of the absorber, which reduced the absorption beyond the resonant wavelength and improved the absorption efficiency of Si3N4 in the low loss range. Furthermore, the absorption intensity and wavelength can be modulated by adjusting the geometric parameters of the structure. We believe this research has good application prospects in mid-infrared lasers, thermal emitters, gas feature sensing, and spectral detection.

Assessment of the Electromagnetic Radiation Exposure at EV Charging Facilities.

As the number of electric vehicles (EV) increases, the number of EV chargers also increases. Charging infrastructure will be built into our close environment. Because of this, the assessment of the electromagnetic field exposure generated from the charger is an important issue. This paper valuates the electromagnetic field exposure of six EV chargers. To assess the level of exposure of EV chargers, the electromagnetic fields from six chargers were measured and analyzed. In addition, measured electromagnetic field exposure levels were evaluated against ICNIRP guidelines. Higher electromagnetic fields were measured with standard chargers than with fast chargers. For the fast charger in the charging state, the magnetic field increased with the charging current. Electromagnetic field exposures for all six chargers did not exceed standard limits. The results of the assessment of the electromagnetic field exposure of the six EV chargers will contribute to the establishment of standards for the evaluation of the electromagnetic field exposure of the EV chargers in the future.

Ultrafast terahertz transparency boosting in graphene meta-cavities

Abstract As an exceptional nonlinear material, graphene offers versatile appealing properties, such as electro-optic tunability and high electromagnetic field confinement in the terahertz regime, spurring advance in ultrashort pulse formation, photodetectors and plasmonic emission. However, limited by atomic thickness, weak light–matter interaction still limits the development of integrated optical devices based on graphene. Here, an exquisitely designed meta-cavities combined with patterned graphene is used to overcome this challenge and promote THz-graphene interaction via terahertz location oscillation. By using an 800 nm pump laser, the local field-induced strong interaction allows sensitive responses to the ultrafast energy transfer from the ultrafast optical pump to graphene electron heat, enabling 46.2% enhancement of terahertz transparency. Such optical modulation of terahertz waves shows ultrafast response in delay less than 10 ps. Moreover, thanks to the nature of graphene, the device shows unique potential for electrically dynamic tuning and further bandwidth broadening.

Empirical studies on the effect of electromagnetic radiation from multiple sources in Dhaka

<span>Just after the invention of electricity by Michael Faraday, there has been a revolution in the communication technology, which lead to the invention of radio, television, radar, satellite, and mobile. While these machines transformed our life high quality, safer and simpler, they have been associated with alarming probable health hazards owing to their electromagnetic radiation (EMR) emission. Couple of cases it has been reported by personals regarding various health related issues relating to exposure on electromagnetic field (EMF) and EMR. Although couple of persons showed light symptoms and respond by avoiding the electrical field (EF) and EMR fields as much as possible, some others are so much affected that they have changed their entire lifestyle. In this paper, empirical survey study has been carried out in the laboratories of Daffodil International University (DIU) main and permanent campus. It was found that some of the instrument had higher EMFs. The findings from this survey may be helpful for the students to take precautionary measurement who work for long duration in the various laboratories for their practical classes and for the users of the domestic appliances as well as office equipment and industrial instruments.</span>

Zinc oxide nanostructures for fluorescence and Raman signal enhancement: a review.

Since the initial discovery of surface-enhanced Raman scattering (SERS) and surface-enhanced fluorescence (SEF), these techniques have shown huge potential for applications in biomedicine, biotechnology, and optical sensors. Both methods rely on the high electromagnetic fields created at locations on the surface of plasmonic metal nanoparticles, depending on the geometry of the nanoparticles, their surface features, and the specific location of analyte molecules. Lately, ZnO-based nanostructures have been exploited especially as SERS substrates showing high enhancement factors and increased charge transfer effect. Additionally, applications focused on enhancing the fluorescence of analyte molecules as well as on tuning the photoluminescence properties of ZnO nanostructures through combination with metal nanoparticles. This review covers the major recent results of ZnO-based nanostructures used for fluorescence and Raman signal enhancement. The broad range of ZnO and ZnO–metal nanostructures synthesis methods are discussed, highlighting low-cost methods and the recyclability of ZnO-based nanosubstrates. Also, the SERS signal enhancement by ZnO-based nanostructures and the influences of lattice defects on the SERS signal are described. The photoluminescence enhancement of ZnO in the presence of noble metal nanoparticles and the molecular fluorescence enhancement in the presence of ZnO alone and in combination with metal nanoparticles are also reviewed.