Application Of Electromagnetic Fields Research Articles

Integrated influence of sulfide modification on the reactivity of nanoscale zero-valent iron towards decabromodiphenyl ether under an electromagnetic field

Individual application of sulfide modification and electromagnetic field (EMF) can enhance the reactivity of nanoscale zero-valent iron (nZVI), yet the potential of both in combination is not clear. This work found that the reactivity of nZVI towards decabromodiphenyl ether was significantly enhanced by the combined effect of sulfidation and EMF. The specific reaction rate constant of nZVI increased by 7 to 10 times. A series of characterization results revealed that the sulfidation level not only affects the inherent reactivity but also the magnetic-induced heating (MIH) and corrosion (MIC) of nZVI. These collectively influence the degradation efficiency of nZVI under EMF. Sulfidation generally diminished the MIH effect. The low degree of sulfidation (S/Fe = 0.1) slightly reduced the MIC effect by 21.4%. However, the high degree of sulfidation (S/Fe = 0.4) led to significantly enhanced MIC effect by 107.1%. For S/Fe = 0.1 and 0.4, the overall enhancement in the reactivity resulting from EMF was alternately dominated by the contributions of MIH and MIC. This work provides valuable insights into the MIH and MIC effects about the sulfidation level of nZVI, which is needed for further exploration and optimization of this combined technology.

Pulsed Radiofrequency Electromagnetic Fields as Modulators of Inflammation and Wound Healing in Primary Dermal Fibroblasts of Ulcers.

Venous leg ulcers are one of the most common nonhealing conditions and represent an important clinical problem. The application of pulsed radiofrequency electromagnetic fields (PRF-EMFs), already applied for pain, inflammation, and new tissue formation, can represent a promising approach for venous leg ulcer amelioration. This study aims to evaluate the effect of PRF-EMF exposure on the inflammatory, antioxidant, cell proliferation, and wound healing characteristics of human primary dermal fibroblasts collected from venous leg ulcer patients. The cells' proliferative and migratory abilities were evaluated by means of a BrdU assay and scratch assay, respectively. The inflammatory response was investigated through TNFα, TGFβ, COX2, IL6, and IL1β gene expression analysis and PGE2 and IL1β production, while the antioxidant activity was tested by measuring GSH, GSSG, tGSH, and GR levels. This study emphasizes the ability of PRF-EMFs to modulate the TGFβ, COX2, IL6, IL1β, and TNFα gene expression in exposed ulcers. Moreover, it confirms the improvement of the proliferative index and wound healing ability presented by PRF-EMFs. In conclusion, exposure to PRF-EMFs can represent a strategy to help tissue repair, regulating mediators involved in the wound healing process.

Pulsating Extremely Low-Frequency Electromagnetic Fields Influence Differentiation of Mouse Neural Stem Cells towards Astrocyte-like Phenotypes: In Vitro Pilot Study.

Even though electromagnetic fields have been reported to assist endogenous neurogenesis, little is known about the exact mechanisms of their action. In this pilot study, we investigated the effects of pulsating extremely low-frequency electromagnetic fields on neural stem cell differentiation towards specific phenotypes, such as neurons and astrocytes. Neural stem cells isolated from the telencephalic wall of B6(Cg)-Tyrc-2J/J mouse embryos (E14.5) were randomly divided into three experimental groups and three controls. Electromagnetic field application setup included a solenoid placed within an incubator. Each of the experimental groups was exposed to 50Hz ELF-EMFs of varied strengths for 1 h. The expression of each marker (NES, GFAP, β-3 tubulin) was then assessed by immunocytochemistry. The application of high-strength ELF-EMF significantly increased and low-strength ELF-EMF decreased the expression of GFAP. A similar pattern was observed for β-3 tubulin, with high-strength ELF-EMFs significantly increasing the immunoreactivity of β-3 tubulin and medium- and low-strength ELF-EMFs decreasing it. Changes in NES expression were observed for medium-strength ELF-EMFs, with a demonstrated significant upregulation. This suggests that, even though ELF-EMFs appear to inhibit or promote the differentiation of neural stem cells into neurons or astrocytes, this effect highly depends on the strength and frequency of the fields as well as the duration of their application. While numerous studies have demonstrated the capacity of EMFs to guide the differentiation of NSCs into neuron-like cells or β-3 tubulin+ neurons, this is the first study to suggest that ELF-EMFs may also steer NSC differentiation towards astrocyte-like phenotypes.

The effects of radiofrequency electromagnetic fields exposure on human self-reported symptoms: A systematic review of human experimental studies

BackgroundThe technological applications of radiofrequency electromagnetic fields (RF-EMF) have been steadily increasing since the 1950s exposing large proportions of the population. The World Health Organization (WHO) is assessing the potential health effects of exposure to RF-EMF. ObjectivesTo systematically assess the effects of exposure to RF-EMF on self-reported non-specific symptoms in human subjects and to assess the accuracy of perceptions of presence or absence of RF-EMF exposure. MethodsEligibility criteria: experimental studies carried out in the general population and in individuals with idiopathic environmental intolerance attributed to EMF (IEI-EMF), in any language.Information sources: Medline, Web of Science, PsycInfo, Cochrane Library, Epistemonikos, Embase and EMF portal, searched till April 2022.Risk of Bias (ROB): we used the RoB tool developed by OHAT adapted to the topic of this review.Synthesis of results: we synthesized studies using random effects meta-analysis and sensitivity analyses, where appropriate. ResultsIncluded studies: 41 studies were included, mostly cross over trials and from Europe, with a total of 2,874 participants.Synthesis of results: considering the primary outcomes, we carried out meta-analyses of 10 exposure-outcomes pairs. All evidence suggested no or small non-significant effects of exposure on symptoms with high (three comparisons), moderate (four comparisons), low (one comparison) and very low (two comparisons) certainty of evidence. The effects (standard mean difference, where positive values indicate presence of symptom being exposed) in the general population for head exposure were (95% confidence intervals) 0.08 (−0.07 to 0.22) for headache, −0.01 (−0.22 to 0.20) for sleeping disturbances and 0.13 (−0.51 to 0.76) for composite symptoms; and for whole-body exposure: 0.09 (−0.35 to 0.54), 0.00 (−0.15 to 0.15) for sleeping disturbances and −0.05 (−0.17 to 0.07) for composite symptoms. For IEI-EMF individuals SMD ranged from −0.19 to 0.11, all of them with confidence intervals crossing the value of zero.Further, the available evidence suggested that study volunteers could not perceive the EMF exposure status better than what is expected by chance and that IEI-EMF individuals could not determine EMF conditions better than the general population. DiscussionLimitations of evidence: experimental conditions are substantially different from real-life situations in the duration, frequency, distance and position of the exposure. Most studies were conducted in young, healthy volunteers, who might be more resilient to RF-EMF than the general population. The outcomes of interest in this systematic review were symptoms, which are self-reported. The available information did not allow to assess the potential effects of exposures beyond acute exposure and in elderly or in chronically ill people. It cannot be ruled out that a real EMF effect in IEI-EMF groups is masked by a mix with insensitive subjects. However, studies on symptoms reporting and/or field perceptions did not find any evidence that there were particularly vulnerable individuals in the IEI-EMF group, although in open provocation studies, when volunteers were informed about the presence or absence of EMF exposure, such differences were consistently observed.Interpretation: available evidence suggests that acute RF-EMF below regulatory limits does not cause symptoms and corresponding claims in the everyday life are related to perceived and not to real EMF exposure status.

Effect of hydroxyapatite and pulsed electromagnetic field on osteogenic differentiation of human stem cells seeded onto 3D‐printed polycaprolactone scaffolds for future bone graft transplantation

AbstractBone graft transplantation is a risky procedure mainly due to postoperative complications. Tissue engineering is an alternative to regenerating bone tissue by seeding mesenchymal stem cells into 3D scaffolds by osteoinductive signaling. Poly(ε‐caprolactone) (PCL) is one of the most used biopolymers for fabricating scaffolds for bone tissue engineering. PCL is enriched with hydroxyapatite (HA) to promote the production of the bone‐mineralized matrix. Moreover, the application of pulsed electromagnetic fields (PEMFs) on scaffolds loaded with HA can significantly benefit collagen and HA networks favoring the interaction between organic and mineral phases of bones. In this context, we investigated, for the first time, the effect exerted by a PEMF exposure on the osteogenic differentiation of human adipose stem cells (hASCs) seeded onto 3D printed PCL‐HA scaffolds and cultured in growth and osteogenic medium (OM). After 21 days of culture, the results showed excellent colonization of scaffolds and the deposition of extracellular matrix (ECM) secreted by hASCs. Immunofluorescence staining confirmed the deposition of collagen type I and osteopontin both on scaffolds. Gene expression analysis indicated that both HA crystal and PEMF treatment were able to trigger osteogenic differentiation, as documented by the increase of osteogenic markers. These results suggest that HA, osteogenic factors, and PEMFs converge on the same signaling pathways as there are no additive effects and no change in protein synthesis between scaffolds with HA or treated with PEMFs for cells cultured in OM. The proposed study lays the foundations for exploring new approaches in bone graft transplantation.

New developments in cosmetic applications of electromagnetic fields: Client and occupational hazard assessment.

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

Hyper- and Hypopigmentation in a Subject with Fitzpatrick Skin Phototype VI: A New Treatment Option.

Background: Laser therapies can cause hyper- and hypopigmentation of the skin. There is little evidence in the literature of effective treatments for these types of problems in Fitzpatrick skin phototypes IV-VI. The main aim of this retrospective study is to evaluate the effects of a new therapy that combines the application of electromagnetic fields and vacuum on a subject with Fitzpatrick skin phototype VI, who presented extensive, laser-induced facial dyschromia. The secondary aim is to test the effectiveness of a free imaging software for assessing skin pigmentation. Methods: The level of improvement after therapy was evaluated, with a 5-point Likert scale, one month after the end of the treatment by the subject and by the doctor who performed the treatment, and by two blinded dermatologists. With the free software, a three-dimensional reconstruction of the treated area and the evaluation of the color distribution were performed. Results: Both the subject and the doctors involved in the study positively evaluated the effects of the treatment. The image analysis highlighted the homogenization of the skin color in the treated area. Conclusions: The combination of electromagnetic fields and vacuum for dyschromia treatments appears promising. The new method of assessing melanin levels resulted particularly efficient.

Neurite Growth and Electrical Activity in PC-12 Cells: Effects of H3 Receptor-Inspired Electromagnetic Fields and Inherent Schumann Frequencies

Cells are continually exposed to a range of electromagnetic fields (EMFs), including those from the Schumann resonance to radio waves. The effects of EMFs on cells are diverse and vary based on the specific EMF type. Recent research suggests potential therapeutic applications of EMFs for various diseases. In this study, we explored the impact of a physiologically patterned EMF, inspired by the H3 receptor associated with wakefulness, on PC-12 cells in vitro. Our hypothesis posited that the application of this EMF to differentiated PC-12 cells could enhance firing patterns at specific frequencies. Cell electrophysiology was assessed using a novel device, allowing the computation of spectral power density (SPD) scores for frequencies between 1 Hz and 128 Hz. T-tests comparing SPD at certain frequencies (e.g., 29 Hz, 30 Hz, and 79 Hz) between the H3-EMF and control groups showed a significantly higher SPD in the H3 group (p < 0.050). Moreover, at 7.8 Hz and 71 Hz, a significant correlation was observed between predicted and percentages of cells with neurites (R = 0.542). Key findings indicate the efficacy of the new electrophysiology measure for assessing PC-12 cell activity, a significant increase in cellular activity with the H3-receptor-inspired EMF at specific frequencies, and the influence of 7.8 Hz and 71 Hz frequencies on neurite growth. The overall findings support the idea that the electrical frequency profiles of developing cell systems can serve as an indicator of their progression and eventual cellular outcomes.

RANDOMIZED COHORT CONTROL STUDY COMPARING THE USE OF STANDARD THERAPY VERSUS STANDARD THERAPY PLUS “SUPER INDUCTIVE MAGNETIC SYSTEM” IN THE TREATMENT OF MUSCULOSKELETAL INJURIES

The pulsed electromagnetic field (PEMF) is considered a promising innovative means in physiotherapy and medicine. The method has wide range of therapeutic effects that address mainly musculoskeletal and neurological disorders. The application of electromagnetic fields (EMF) in medicine has a long history. Magnetic fields (MF) were created by passing electric currents through a wire coil placed above the fracture. Through Faraday induction, periodic variations in the MF created the appropriate electrical field in bone [1]. The biological effects of pulsed MF on nerve tissue have received significant study in recent decades [2]. The aim of this study was to evaluate the efficacy of Super Inductive Magnetic system in people with musculoskeletal pain. SIS therapy was compared with standard therapy. Statistical analysis showed that the difference between groups was significant (p < 0.001), which proves that SIS therapy is more effective compared to standard therapy. SIS is safe and effective method for treatment of musculoskeletal pain. Further investigations need to be done to provide more accurate data and to evaluate the effectiveness of this method compared to other treatment methods.

Modulation of Inflammatory Response by Electromagnetic Field Stimulation in Traumatic Brain Injury in Yucatan Swine.

Traumatic brain injury is a leading cause of disability and death worldwide and represents a high economic burden for families and national health systems. After mechanical impact to the head, the first stage of the damage comprising edema, physical damage, and cell loss gives rise to a second phase characterized by glial activation, increased oxidative stress and excitotoxicity, mitochondrial damage, and exacerbated neuroinflammatory state, among other molecular calamities. Inflammation strongly influences the molecular events involved in the pathogenesis of TBI. Therefore, several components of the inflammatory cascade have been targeted in experimental therapies. Application of Electromagnetic Field (EMF) stimulation has been found to be effective in some inflammatory conditions. However, its effect in the neuronal recovery after TBI is not known. In this pilot study, Yucatan miniswine were subjected to TBI using controlled cortical impact approach. EMF stimulation via a helmet was applied immediately or two days after mechanical impact. Three weeks later, inflammatory markers were assessed in the brain tissues of injured and contralateral non-injured areas of control and EMF-treated animals by histomorphometry, immunohistochemistry, RT-qPCR, Western blot, and ELISA. Our results revealed that EMF stimulation induced beneficial effect with the preservation of neuronal tissue morphology as well as the reduction of inflammatory markers at the transcriptional and translational levels. Immediate EMF application showed better resolution of inflammation. Although further studies are warranted, our findings contribute to the notion that EMF stimulation could be an effective therapeutic approach in TBI patients.

Fe/amorphous-Al2SiO5 composites fabricated by low-temperature solid-phase reaction densification achieve synergistically enhanced structural and soft magnetic properties

To date, an urgent problem for various metal-based soft magnetic composites (SMCs) is that it is difficult to simultaneously achieve high strength and optimum magnetic performance, which actually restricts their large-scale applications in many electromagnetic fields. In this work, we have tried to resolve this basic problem by proposing a new concept of low-temperature solid-phase reaction densification instead of conventional particle-deformation densification to fabricate high-performance metal-based SMCs. Specifically, fully-densified nanoscale amorphous Al2SiO5 coating layers are formed through a solid phase reaction at 500 °C between initially-prepared nano-sized amorphous SiO2 and amorphous Al2O3, and meanwhile coated in situ on the surface of deformed Fe to fabricate novelly-structured Fe/amorphous-Al2SiO5 SMCs. The low-temperature solid-phase reaction for fabrication of Fe/amorphous-Al2SiO5 SMCs can avoid negative effects of high processing temperature for conventional metal-based SMCs on their structure and magnetism resulting in their high strength, increased resistivity, low core loss and high saturation magnetic inductions. Thus, Fe/amorphous-Al2SiO5 SMCs show synergistically enhanced structural and soft magnetic properties, which exceed those of most conventional metal-based SMCs. This work also provides a special and useful insight into the design and applications of metal-based composites needing both functional and structural properties.

Pulsed electromagnetic field stimulation enhances neurite outgrowth in neural cells and modulates inflammation in macrophages

Nerve regeneration following traumas remains an unmet challenge. The application of pulsed electromagnetic field (PEMF) stimulation has gained traction for a minimally invasive regeneration of nerves. However, a systematic exploration of different PEMF parameters influencing neuron function at a cellular level is not available. In this study, we exposed neuroblastoma F11 cells to PEMF to trigger beneficial effects on neurite outgrowth. Different carrier frequencies, pulse repetition frequencies, and duty cycles were screened with a custom ad hoc setup to find the most influential parameters values. A carrier frequency of 13.5 MHz, a pulse repetition frequency of 20 Hz, and a duty cycle of 10% allowed maximal neurite outgrowth, with unaltered viability with respect to non-stimulated controls. Furthermore, in a longer-term analysis, such optimal conditions were also able to increase the gene expression of neuronal expression markers NeuN and Tuj-1 and transcription factor Ngn1. Finally, the same optimal stimulation conditions were also applied to THP-1 macrophages, and both pro-inflammatory (TNF-α, IL-1β, IL-6, IL-8) and anti-inflammatory cytokines (IL-10, CD206) were analyzed. The optimal PEMF stimulation parameters did not induce differentiation towards an M1 macrophage phenotype, decreased IL-1β and IL-8 gene expression, decreased TNF-α and IL-8 cytokine release in M1-differentiated cells, increased IL-10 and CD206 gene expression, as well as IL-10 cytokine release in M0 cells. The specific PEMF stimulation regime, which is optimal in vitro, might have a high potential for a future in vivo translation targeting neural regeneration and anti-inflammatory action for treating peripheral nerve injuries.

Radiofrequency and pulsed electromagnetic field application following liposuction-Clinical evaluation of performance and safety.

With more than 1.5 million performed procedures, liposuction was the second most performed esthetic surgical procedure all over the world in males and in females in the year 2020. The objective of this open-label, evaluator-blinded study was to assess the efficacy and safety of an energy-based device that combines multipolar radiofrequency with pulsed electromagnetic field (PEMF) in patients that underwent liposuction. A total of 30 subjects, of whom 24 were females (80%), with a mean age of 48.4 ± 11.0 years (range: 27-69 years) and a mean weight of 69.5 ± 11.7 kg underwent unilateral treatment with radiofrequency and application of PEMF after bilateral liposuction. One month after the last of a total of six weekly treatments, skin elasticity, visco-elasticity and net elasticity, as well as subject reported satisfaction on a 5-point scale ranging from -1 (worse) to 3 (very much improved) and esthetic improvement ranging from 0 (very unsatisfied) to 4 (very satisfied) rated by three independent reviewers were assessed. Three independent and blinded reviewers rated the improvement of the treated side on average as 1.17 + 0.07 compared with baseline. Subjects were very satisfied with their treatment, with a mean score of 3.24 (0.03) out of 4 at the 1-month follow-up visit. Cutometer measurements showed no significant changes. This study revealed that the subjective satisfaction with the results of the application of RF and PEMF after liposuction is high, while at the same time the esthetic appearance as rated by independent raters improved on the treated side.

Fine-tunable ε′-negative response derived from low-frequency plasma oscillation in graphene/polyaniline metacomposites

Remarkable ε′-negative responses at radio-frequency endow metacomposites with revolutionary applications in electromagnetic (EM) fields. However, uncovering its regulation mechanism and subsequently achieving fine-tunable ε′-negative response remains challenging. Here, we meticulously designed graphene/polyaniline (GR/PANI) metacomposites above percolation, which directly enable tunable negative permittivity at an order of magnitude of −103. By rationally adjusting the three-dimensional GR network, we were able to form collective low-frequency plasma oscillation of free electrons in composites, which intrinsically contributes to the tunable ε′-negative response. Moreover, an ε′-near-zero (ENZ) response was surprisingly observed at ∼920 MHz due to the ineffectiveness of the plasmonic state at high frequencies. In addition, we carried out equivalent circuit analysis to demonstrate the phase relationship and electrical characteristics of these metacomposites. This work could contribute to a new category of polymer-matrix composites and enable exotic properties beyond their natural and bulk counterparts.

Application of a Magnetic Field to Enhance the Environmental Sustainability and Efficiency of Microbial and Plant Biotechnological Processes

Despite the growing prevalence of using living organisms in industry, the control of biotechnological processes remains highly complex and constitutes one of the foremost challenges in these applications. The usage of electromagnetic fields offers a great opportunity to control various biotechnological processes by alternating growth and cell metabolism without influencing the characteristics of the cultivation medium or the products of the biotechnological process. The investigation of electromagnetic field applications across various industries, including food production, medicine, and pollutant mitigation, has yielded substantial insights. We used the scientific databases PubMed and ScienceDirect to select 103 experimental and theoretical articles that included original results suitable for further investigation. This type of search was repeated with every new relevant article iteratively until no new articles could be detected. Notably, even weak, low-frequency magnetic fields can accelerate the growth of certain organisms, further stabilize the bacterial community in activated sludge within wastewater treatment plants, enhance the fermentation capabilities of both yeast and bacteria, enhance metal bioleaching by the activation of bacterial metabolism, or improve the metal tolerance of plants during the phytoremediation process. Moreover, magnetic fields exhibit a promising sustainable possibility for the better control of biotechnological processes, thus making these processes more competitive compared with the currently used long-term unsustainable extraction of metals. Although with these interesting results, these examples represent highly exceptional applications. Despite these examples, the overall application potential of magnetic fields remains largely unexplored and unknown.

Performance of different magnetic and electromagnetic water treatment devices on soil and two tomato cultivars

The application of magnetic and Electromagnetic fields for irrigation water treatment is still an attractive and promising process for the alleviation of the adverse effects of salinity and the enhancement of crop production. Hence, a study was initiated to test the effectiveness of different commercial magnetic and electromagnetic water. treatment devices on soil and two Tunisian tomato crop cultivars, Senda and Dorra. For this purpose, a field experiment was conducted at the experimental Station of Cherfech, located in the north of Tunisia. A randomized complete design with three replicates was used and five magnetic, GMX (1.2 T), Magiko (1.6 T), Deltawater (1.4 T), and Magnolith (0.62T), and electromagnetic Aqua-4D (0.0043T) treatment devices were applied for the treatment of a moderate saline water (EC = 2.9 dS m–1). Results showed that different magnetic and electromagnetic treatments tended to reduce soil salinity and pH, improve crop growth, yield, and fruit caliber, but decline the total soluble solids (°Brix) and the titratable acidity of both tomato cultivars. The greatest Magnetic effects were shown for Senda cultivar with Aqua 4-D treatment, whereas the least effect was recorded for Dorra cultivar with Magiko treatment. Accordingly, the influence of magnetic and electromagnetic treatment of irrigation water on soil and tomatoes depends on the choice of tomato cultivar and increases with the following trends: Magiko < Deltawater < GMX < Magnolith < Aqua 4-D. Likewise, their influence depends on their field intensity, which increases in the trend of: 1.6 T < 1.4T < 1.2T < 0.62T < 0.0043T, suggesting that the performance of each device increases as magnetic field intensity decreases. This study highlights that an electromagnetic device (Aqua 4-D) with a weak field intensity (<0.5mT) could also have similar effects to that of a magnetic device (Magnolith).

DEVELOPMENT OF MR-BASED PROCEDURES FOR THE IMPLEMENTATION OF PATIENT-SPECIFIC DIELECTRIC MODELS FOR CLINICAL USE

Nowadays, many medical techniques are based on the application of electromagnetic fields (EMF) on human body. For the optimization of these techniques, it is necessary to understand the mechanisms of interaction between the biological system under exposure and the applied EMF. Since this interaction is described by the dielectric properties of the biological system, an accurate dielectric characterization of human body is necessary. Biological tissues are complex and heterogeneous, and their dielectric properties can vary significantly from the ex-vivo to the in vivo condition. For this reason, there is the need to measure these properties for a specific subject. Unfortunately, traditional techniques used to measure dielectric properties of tissues are not able to reach this aim and an alternative method must be devised. In this work, a model is proposed for the reconstruction of dielectric properties of biological tissues from MR acquisitions. This model is wideband, specific, applicable in vivo and useful for those medical techniques that need a precise dielectric characterization of the patients.

Smart shape memory composite foam enabled rapid and conformal manipulation of electromagnetic wave absorption performance

With the development of communication and electronic technologies, smart electromagnetic wave (EMW) absorption materials with tunable performance are highly desirable for applications under complicated electromagnetic circumstances. However, the performance of the ordinary EMW absorption materials is dominated by their electromagnetic parameters which are constant unless their compositions are changed. This study presents a porous EMW absorption material with adjustable effective absorption bandwidth (EAB) and reflection loss (RL) to satisfy the requirements of tunability for complex electromagnetic applications. First, a composite foam is fabricated by assembling the reduced graphene oxide (rGO) to the melamine sponge (MS) framework. Next, the thermoplastic polyurethane (TPU) is introduced to endow the MS/rGO composites with the desired shape memory property after crosslinking. In specific, the obtained MS/rGO composites show high flexibility, elasticity, and low density of 10.7 mg cm−3, and present the minimum RL of −63.29 dB with EAB of 7.18 GHz. Additionally, the tunable EMW absorption performance of MS/rGO-TPU composites is achieved through their shape memory effect. Notably, the EAB can be adjusted to a wide range from 5.5 to 18 GHz under the compressive deformations of those composites as modulated by cooling/heating, and correspondingly the minimum RL changes from −15.4 dB down to −39.2 dB. In a word, the smart, lightweight MS/rGO and MS/rGO-TPU composite foams with adjustable EMW absorption performance are strong candidates for practical applications in complex electromagnetic fields.

Challenges in unconventional catalysis

Catalysis science and technology increased efforts recently to progress beyond conventional "thermal" catalysis and face the challenges of net-zero emissions and electrification of production. Nevertheless, a better gaps and opportunities analysis is necessary. This review analyses four emerging areas of unconventional or less-conventional catalysis which share the common aspect of using directly renewable energy sources: (i) plasma catalysis, (ii) catalysis for flow chemistry and process intensification, (iii) application of electromagnetic (EM) fields to modulate catalytic activity and (iv) nanoscale generation at the catalyst interface of a strong local EM by plasmonic effect. Plasma catalysis has demonstrated synergistic effects, where the outcome is higher than the sum of both processes alone. Still, the underlying mechanisms are complex, and synergy is not always obtained. There is a crucial need for a better understanding to (i) design catalysts tailored to the plasma environment, (ii) design plasma reactors with optimal transport of plasma species to the catalyst surface, and (iii) tune the plasma conditions so they work in optimal synergy with the catalyst. Microfluidic reactors (flow chemistry) is another emerging sector leading to the intensification of catalytic syntheses, particularly in organic chemistry. New unconventional catalysts must be designed to exploit in full the novel possibilities. With a focus on (a) continuous-flow photocatalysis, (b) electrochemical flow catalysis, (c) microwave flow catalysis and (d) ultrasound flow activation, a series of examples are discussed, with also indications on scale-up and process industrialisation. The third area discussed regards the effect on catalytic performances of applying oriented EM fields spanning several orders of magnitude. Under well-defined conditions, gas breakdown and, in some cases, plasma formation generates activated gas phase species. The EM field-driven chemical conversion processes depend further on structured electric/magnetic catalysts, which shape the EM field in strength and direction. Different effects influencing chemical conversion have been reported, including reduced activation energy, surface charging, hot spot generation, and selective local heating. The last topic discussed is complementary to the third, focusing on the possibility of tuning the photo- and electro-catalytic properties by creating a strong localised electrical field with a plasmonic effect. The novel possibilities of hot carriers generated by the plasmonic effect are also discussed. This review thus aims to stimulate the reader to make new, creative catalysis to address the challenges of reaching a carbon-neutral world.

Electromagnetic investigation of neuron growth by using pulsed electromagnetic field stimulation

Electromagnetic field (EMF) applications for humans have been widely used for medical therapy for a long time. Various nerve diseases such as complex regional pain syndrome, cerebral palsy and spinal cord injuries may occur as a result of damage on the nerve cells. In addition, EMF applications are taken into consideration in terms of tissue regeneration. The use of electricity for nerve regeneration is applied internally or externally. The use of direct current (DC) electric fields to stimulate axon elongation and nerve regeneration in nerve cells has been applied in various studies. In our study, electromagnetic field was used for the controlled and directional growth of Dorsal Root Ganglia (DRG) nerve cells. An amplifier circuit, which can produce amplified signals to generate proposed pulsed electromagnetic fields (PEMF) is designed. The electromagnetic field is produced on FR-4 copper plate, which highlights electrical field unlike previous studies, since there is no circular coil structure preferred. The elongation of nerve cells is planned to be in one direction, hence the signal to be applied is produced as a novel asymmetrical waveform (sawtooth) in addition to triangular and square waveforms which were previously preferred in recent studies. By the aid of proposed novel construction and produced signal waveform, PEMF system can be applied for nerve diseases effectively. The morphological nerve cell elongation results and PEMF results have been investigated and the effectiveness of the proposed system is verified.