Electromagnetic Modulation of Cell Behavior: Unraveling the Positive Impacts in a Comprehensive Review.

There are numerous effective procedures for cell signaling, in which humans directly transmit detectable signals to cells to govern their essential behaviors. From a biomedical perspective, the cellular response to the combined influence of electrical and magnetic fields holds significant promise in various domains, such as cancer treatment, targeted drug delivery, gene therapy, and wound healing. Among these modern cell signaling methods, electromagnetic fields (EMFs) play a pivotal role; however, there remains a paucity of knowledge concerning the effects of EMFs across all wavelengths. It's worth noting that most wavelengths are incompatible with human cells, and as such, this study excludes them from consideration. In this review, we aim to comprehensively explore the most effective and current EMFs, along with their therapeutic impacts on various cell types. Specifically, we delve into the influence of alternating electromagnetic fields (AEMFs) on diverse cell behaviors, encompassing proliferation, differentiation, biomineralization, cell death, and cell migration. Our findings underscore the substantial potential of these pivotal cellular behaviors in advancing the treatment of numerous diseases. Moreover, AEMFs wield a significant role in the realms of biomaterials and tissue engineering, given their capacity to decisively influence biomaterials, facilitate non-invasive procedures, ensure biocompatibility, and exhibit substantial efficacy. It is worth mentioning that AEMFs often serve as a last-resort treatment option for various diseases. Much about electromagnetic fields remains a mystery to the scientific community, and we have yet to unravel the precise mechanisms through which wavelengths control cellular fate. Consequently, our understanding and knowledge in this domain predominantly stem from repeated experiments yielding similar effects. In the ensuing sections of this article, we delve deeper into our extended experiments and research.

Inner Ear Function Evaluation in Mobile Phone Users: A Cross-Sectional Study From a Tertiary Care Centre in North India.

Background India has approximately 1.02 billion mobile phone users. The electromagnetic radiations emitted by telecommunication systems are absorbed by the recipient's body, leading to changes in brain electrical activity, sensations of warmth or burning around the ear, and alterations in the blood-brain barrier. The inner ear, being the closest organ during mobile phone use, directly receives these electromagnetic radiations. This study aims to assess the inner ear function among mobile phone users, investigate the impact of mobile phones on the hearing thresholds of volunteers through pure-tone audiometry (PTA), and delve into the same using otoacoustic emissions (OAE). Methodology A cross-sectional study was conducted at a single center in North India from September 2020 to March 2021. The sample size of around 100 was determined using G Power software (G Power, Aichach, Germany), including volunteers aged 18-25, using mobile phones for over a year with normal hearing. Exclusions involved various ear-related histories or chronic systemic illnesses. Dominant and non-dominant ear groups were formed based on mobile phone usage. The study involved comprehensive ENT examinations, pure-tone audiometry, and otoacoustic emissions. We performed statistical analyses using SPSS version 22.0 (IBM Corp., Armonk, NY), which presented descriptive statistics and employed tests for group comparisons. Results Most participants were in the 21-23 age group (56%), with a mean age of 22.16 ± 1.77 years. There were 45 males and 55 females. The mean mobile phone usage was 6.6 ± 1.98 years, with varying daily durations. The dominant ear for mobile phone usage was predominantly the right ear (75 participants). Pure-tone audiometry results showed no statistically significant differences between dominant and non-dominant ears. Among the 24 participants with absent OAE, no significant association was found with mobile phone usage duration. Notably, the highest incidence of absent OAE occurred in the 120-180-minute usage category. Conclusion Mobile phones have seamlessly integrated into the lives of individuals, witnessing an exponential increase in users over time. The inner ear, situated in proximity to mobile phone usage, is of particular concern. While there is existing evidence indicating potential adverse effects of mobile phones on the inner ear, further long-term studies involving larger populations are essential to comprehensively evaluating the impact on inner ear function among mobile phone users.

New Shear Horizontal (SH) Surface-Plasmon-Polariton-like Elastic Surface Waves for Sensing Applications.

The advent of elastic metamaterials at the beginning of the 21st century opened new venues and possibilities for the existence of new types of elastic (ultrasonic) surface waves, which were deemed previously impossible. In fact, it is not difficult to prove that shear horizontal (SH) elastic surface waves cannot exist on the elastic half-space or at the interface between two conventional elastic half-spaces. However, in this paper we will show that SH elastic surface waves can propagate at the interface between two elastic half-spaces, providing that one of them is a metamaterial with a negative elastic compliance s44(ω). If in addition, s44(ω) changes with frequency ω as the dielectric function ε(ω) in Drude's model of metals, then the proposed SH elastic surface waves can be considered as an elastic analogue of surface plasmon polariton (SPP) electromagnetic waves, propagating at a metal-dielectric interface. Due to inherent similarities between the proposed SH elastic surface waves and SPP electromagnetic waves, the new results developed in this paper can be readily transferred into the SPP domain and vice versa. The proposed new SH elastic surface waves are characterized by a strong subwavelength confinement of energy in the vicinity of the guiding interface; therefore, they can potentially be used in subwavelength ultrasonic imaging, superlensing, and/or acoustic (ultrasonic) sensors with extremely high mass sensitivity.

A Review of Nitrogen-Doped Graphene Aerogel in Electromagnetic Wave Absorption.

Graphene aerogels (GAs) possess a remarkable capability to absorb electromagnetic waves (EMWs) due to their favorable dielectric characteristics and unique porous structure. Nevertheless, the introduction of nitrogen atoms into graphene aerogels can result in improved impedance matching. In recent years, nitrogen-doped graphene aerogels (NGAs) have emerged as promising materials, particularly when combined with magnetic metals, magnetic oxides, carbon nanotubes, and polymers, forming innovative composite systems with excellent multi-functional and broadband absorption properties. This paper provides a comprehensive summary of the synthesis methods and the EMW absorption mechanism of NGAs, along with an overview of the absorption properties of nitrogen-doped graphene-based aerogels. Furthermore, this study sheds light on the potential challenges that NGAs may encounter. By highlighting the substantial contribution of NGAs in the field of EMW absorption, this study aims to facilitate the innovative development of NGAs toward achieving broadband absorption, lightweight characteristics, and multifunctionality.

Early protection against bone stress injuries by mobilization of endogenous targeted bone remodeling.

Bone stress injuries are common overuse injuries, especially in soldiers, athletes, and performers. In contrast to various post-injury treatments, early protection against bone stress injuries can provide greater benefit. This study explored the early protection strategies against bone stress injuries by mobilization of endogenous targeted bone remodeling. The effects of various pharmaceutical/biophysical approaches, individual or combinational, were investigated by giving intervention before fatigue loading. We optimized the dosage and administration parameters and found that early intervention with pulsed electromagnetic field and parathyroid hormone (i.e., PEMF+PTH) resulted in the most pronounced protective effects among all the approaches against the bone stress injuries. In addition, the mechanisms by which the strategy mobilizes targeted bone remodeling and enhances the self-repair capacity of bone were systematically investigated. This study proposes strategies to reduce the incidence of bone stress injuries in high-risk populations (e.g., soldiers and athletes), particularly for those before sudden increased physical training.

Electromagnetic field exposure to human head model with various metal objects at sub-6 GHz frequencies.

In recent years, the interactions of metal objects in human body with electromagnetic fields caused by devices working at fifth-generation (5G) frequencies have been studied by various researchers. A motivation behind this research was to evaluate the human body absorption of electromagnetic energy operating at sub-6 GHz 5G applications. According to this, the specific absorption rate (SAR) caused by new generation mobile phones was investigated in human heads wearing metal-framed spectacles and having metallic implants or earrings to analyse electromagnetic field exposure. A realistic human head model, including some metal objects, was numerically calculated, and analysed in terms of non-ionizing dosimetry. Simulations were carried out with the finite integration technique (FIT) based commercial software in the frequencies of 0.9, 1.8, 2.1, 2.45, 3.5 and 5 GHz, respectively. The maximum SAR of 14 × 10-5 W/kg for 10 g average tissue was calculated at 2.45 GHz frequency in the head model with earrings. The highest electric field strength of 0.52 V/m was observed at a 1.8 GHz frequency in the head model with all metal objects equipped. Results show that metal objects such as spectacles, dental implants and earrings can cause an increase in the SAR values for external biological tissues, and metal objects can behave as a kind of shield for deeper tissues. However, the obtained values are below the limits of international organisations.

Optimizing Cardiac Wireless Implant Communication: A Feasibility Study on Selecting the Frequency and Matching Medium.

Cardiac wireless implantable medical devices (CWIMD) have brought a paradigm shift in monitoring and treating various cardiac conditions, including heart failure, arrhythmias, and hypertension. One of the key elements in CWIMD is the implant antenna which uses radio frequency (RF) technology to wirelessly communicate and transmit data to external devices. However, wireless communication with a deeply implanted antenna using RF can be challenging due to the significant loss of electromagnetic (EM) signal at the air-skin interface, and second, due to the propagation and reflection of EM waves from different tissue boundaries. The air-skin interface loss of the EM wave is pronounced due to the absence of a matching medium. This paper investigates the EM propagation losses in the human body and presents a choice of optimal frequency for the design of the cardiac implant antenna and the dielectric properties of the matching medium. First, the dielectric properties of all tissues present in the human thorax including skin, fat, muscle, cartilage, and heart are analyzed as a function of frequency to study the EM wave absorption at different frequencies. Second, the penetration of EM waves inside the biological tissues is analyzed as a function of frequency. Third, a transmission line (TL) formalism approach is adopted to examine the optimal frequency band for designing a cardiac implant antenna and the matching medium for the air-skin interface. Finally, experimental validation is performed at two ISM frequencies, 433 MHz and 915 MHz, selected from the optimal frequency band (0.4-1.5 GHz) suggested by our analytical investigation. For experimental validation, two off-the-shelf flexible dipole antennas operating at selected ISM frequencies were used. The numerical and experimental findings suggested that for the specific application of a cardiac implant with a penetration depth of 7-17 cm, the most effective frequency range for operation is within 0.4-1.5 GHz. The findings based on the dielectric properties of thorax tissues, the penetration depth of EM waves, and the optimal frequency band have provided valuable information on developing and optimizing CWIMDs for cardiac care applications.

A Microwave Field-Induced Nonlinear Metamaterial with Wafer Integration Level.

Field-induced nonlinear materials, with extended abilities of manipulating electromagnetic waves, have been widely employed in electromagnetic protection, absorption, and detection. Until now, it was found that the field-induced nonlinearity mainly shows in the optical and terahertz frequency bands. Applying the microwave band into such technical activities is hampered due to a lack of investigations on the nonlinearity caused by microwave electric fields, especially in the ultrawideband and microwave high-frequency bands. In this paper, a nonlinear metamaterial (NLMM) concept based on the integration of metamaterial structures and a semiconductor on the same wafer is proposed, which shows nonlinear behavior to the electromagnetics' field energy in the microwave band. The designed NLMM is transparent to low-density electromagnetic radiation fields, while it adaptively becomes opaque to high-density electromagnetic radiation fields. Two types of NLMM are designed to verify the nonlinear characteristics of ultrawide and narrow bands in the microwave band, respectively. The concept of NLMM can be used for the application of the microwave frequency band in electromagnetic protection and detection.

In-situ preparation of CoFe2O4 nanoparticles on eggshell membrane-activated carbon for microwave absorption.

This study explores the potential of using cobalt ferrite (CF) nanoparticles grown in situ on eggshell membranes (ESM) to mitigate the increasing problem of electromagnetic interference (EMI). A simple carbonization process was adopted to synthesize CF nanoparticles on ESM. The study further examines the composites' surface morphology and chemical composition and evaluates their microwave absorption performance (MAP) at X-band frequency. Results showed that the composite of CF and ESM - CESM@CF, exhibited a strong RL peak value of -39.03 mm with an optimal thickness of 1.5 mm. The combination of CF and ESM demonstrates excellent impedance matching and EM wave attenuation. The presence of numerous interfaces, conduction loss from the morphology, interfacial polarisation, and dual influence from both CF and ESM contribute to the high MAP of the composite. CESM@CF composite is projected as an excellent biomass-based nano-composite for EM wave absorption applications.

Combating Coronavirus Using Resonant Electromagnetic Irradiation.

The interaction of electromagnetic (EM) waves with the COVID-19 virus is studied to define the frequencies that cause maximum energy absorption by the virus and the power level needed to cause a lethal temperature rise. The full-wave EM simulator is used to model the virus and study the effects of its size and dielectric properties on the absorbed power across a wide range of frequencies. The results confirm potential resonance conditions, where specific frequencies produce maximum absorption and subsequent temperature rise that can destroy the virus. Furthermore, the study confirms that maximum power deposition in the virus occurs at specific wavelengths depending on its size. Also, the simulation is used to find the power required to destroy the virus and determine the total power required to destroy it in an oral activity, such as coughing, made by infected individuals. Furthermore, the study explained why irradiation by UV-C band is effective to decrease virus activity or even eradicate it.

Investigation of Electromagnetic Wave Absorption Properties of Ni-Co and MWCNT Nanocomposites.

BACKGROUND: In recent years, severe electromagnetic interference among electronic devices has been caused by the unprecedented growth of communication systems. Therefore, microwave absorbing materials are required to relieve these problems by absorbing the unwanted microwave. In the design of microwave absorbers, magnetic nanomaterials have to be used as fine particles dispersed in an insulating matrix. Besides the intrinsic properties of these materials, the structure and morphology are also crucial to the microwave absorption performance of the composite. In this study, Ni-Co-MWCNT composites were synthesized, and the changes in electric permittivity, magnetic permeability, and reflectance loss of the samples were evaluated at frequencies of 2 to 18 GHz. METHODS: Nickel-Cobalt-Multi Wall Carbon Nanotubes (MWCNT) composites were successfully synthesized by the co-precipitation chemical method. The structural, morphological, and magnetic properties of the samples were characterized and investigated by X-ray diffractometer (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Vibrating Sample Magnetometer (VSM), and Vector Network Analyzer (VNA). RESULTS: The results revealed that the Ni-Co-MWCNT composite has the highest electromagnetic wave absorption rate with a reflectance loss of -70.22 dB at a frequency of 10.12 GHz with a thickness of 1.8 mm. The adequate absorption bandwidth (RL <-10 dB) was 6.9 GHz at the high-frequency region, exhibiting excellent microwave absorbing properties as a good microwave absorber. CONCLUSION: Based on this study, it can be argued that the Ni-Co-MWCNT composite can be a good candidate for making light absorbers of radar waves at frequencies 2- 18 GHz.

5G Electromagnetic Radiation Attenuates Skin Melanogenesis In Vitro by Suppressing ROS Generation.

Recently, the impacts of 5G electromagnetic radiation (EMR) with 28 GHz on human health have been attracting public attention with the advent of 5G wireless communication. Here, we report that 5G (28 GHz) EMR can attenuate the skin pigmentation in murine melanoma cells (B16F10) and a 3D pigmented human epidermis model (Melanoderm™). B16 cells were exposed to 5G (28 GHz) with or without α-MSH for 4 h per day. Interestingly, 5G attenuated α-MSH-induced melanin synthesis. Fontana-Masson staining confirmed that the dendritic formation of α-MSH stimulated B16 cells was diminished by 5G exposure. To confirm the anti-melanogenic effect of 5G EMR, MelanoDerm™ was irradiated with 5G at a power intensity of 10 W/m2 for 4 h a day for 16 days and melanin distribution was detected with Fontana-Masson staining, which supported the anti-melanogenic effect of 5G EMR. Consistently, 5G EMR suppressed α-MSH induced upregulation of melanogenic enzymes; tyrosinase, TRP-1, and TRP-2. Of note, 5G EMR attenuated ROS production stimulated by α-MSH and H2O2, suggesting that 5G EMR may dissipate ROS generation, which is pivotal for the melanin synthesis. Collectively, we demonstrated that 5G EMR can attenuate skin pigmentation by attenuating ROS generation.

Estimation of some antioxidants in people exposed to electromagnetic waves from Internet towers in Samarra.

The current study was conducted as a preliminary study in the Samarra city of Iraq. The study explored direct and indirect impact on people exposed to Internet network towers on residential premises in the cities of Iraq. The study included collection of samples from people exposed to radioactive frequencies of Internet towers for a period ranging from 1 to 10 years. In all, 43 blood samples of males and female participants (age: 20-35 years) were collected exposed to radioactive frequencies (present at the places where constellations were located); also, 20 samples were collected from those (20-35-year old) not exposed to radioactive frequencies (from places far from the Internet towers), which acted as a control group. Measurements and analyses were made for antioxidants that included the following enzymes: glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), and peroxynitrate (or peroxonitrite [ONOO-]). Antioxidants are one of the most essential lines of defense against free radicals that cause diseases and premature aging. The results demonstrated a significant increase in the levels of GPx and SOD concentrations and a decrease in the levels of GSH concentration in the blood serum of participants exposed to electromagnetic waves of Internet towers compared to the control group. The results also showed a significant increase in the concentrations of both MDA and ONOO- compared to the non-exposed subjects of the control group.

Design and Analysis of Multi-Layer and Cuboid Coding Metamaterials for Radar Cross-Section Reduction.

This research aimed to develop coding metamaterials to reduce the Radar Cross-Section (RCS) values in C- and Ku-band applications. Metamaterials on the macroscopic scale are commonly defined by effective medium parameters and are categorized as analogue. Therefore, coding metamaterials with various multi-layer and cuboid designs were proposed and investigated. A high-frequency electromagnetic simulator known as computer simulation technology was utilised throughout a simulation process. A one-bit coding metamaterial concept was adopted throughout this research that possesses '0' and '1' elements with 0 and π phase responses. Analytical simulation analyses were performed by utilising well-known Computer Simulation Technology (CST) software. Moreover, a validation was executed via a comparison of the phase-response properties of both elements with the analytical data from the High-Frequency Structure Simulator (HFSS) software. As a result, promising outcomes wherein several one-bit coding designs for multi-layer or coding metamaterials manifested unique results, which almost reached 0 dBm2 RCS reduction values. Meanwhile, coding metamaterial designs with larger lattices exhibited optimised results and can be utilised for larger-scale applications. Moreover, the coding metamaterials were validated by performing several framework and optimal characteristic analyses in C- and Ku-band applications. Due to the ability of coding metamaterials to manipulate electromagnetic waves to obtain different functionalities, it has a high potential to be applied to a wide range of applications. Overall, the very interesting coding metamaterials with many different sizes and shapes help to achieve a unique RCS-reduction performance.

Intensidad lumínica de las lámparas de fotocurado LED en los consultorios odontológicos de Piura, Perú / Output intensity of LED light curing units in dental offices of Piura, Peru

Introducción: La lámpara de fotocurado, que utiliza diodos emisores de luz (LED), se emplea en odontología para la conversión polimérica de los materiales de restauración dental. Se ha comunicado que una intensidad lumínica inadecuada de la lámpara no aseguraría la correcta polimerización del material de restauración. Objetivo: Determinar la intensidad lumínica de las lámparas de fotocurado LED en consultorios odontológicos de la ciudad de Piura, Perú, 2020. Métodos: Estudio observacional, descriptivo. Se midió la intensidad lumínica en 70 lámparas de fotocurado LED, usando un radiómetro con una longitud de onda de 400-500 nm, con capacidad de medida de la intensidad lumínica de hasta 3500 mw/cm2. Por debajo de los 400 mw/cm2 indica intensidad baja, de 400 a 800 mw/cm2 intensidad media, de 800 a 1200 mw/cm2 intensidad alta y por encima de los 1200 mw/cm2 indica intensidad muy alta. Resultados: El 48,5 por ciento de las lámparas analizadas presentaban intensidad media, el 22,86 por ciento intensidad alta, mientras que el 15,71 por ciento intensidad baja y finalmente el 12,86 por ciento de las lámparas presentaban intensidad muy alta. Se reportó menor frecuencia de lámparas con mayor uso clínico. Conclusiones: Las lámparas de fotocurado LED, utilizadas en los consultorios dentales de la provincia de Piura durante el 2020, emiten una intensidad lumínica promedio de 778,14 mW/cm2, equivalente a la intensidad media(AU)

Introduction: Light curing lamps that use light-emitting diodes (LED) are used in dentistry for the polymeric conversion of dental restorative materials. It has been reported that inadequate light intensity in the lamp would not ensure the appropriate polymerization of restorative materials. Objective: Determine the output intensity of LED light curing units used in dental offices of the city of Piura, Peru, in the year 2020. Methods: An observational descriptive study was conducted. Measurements were taken of the light output of 70 LED light curing lamps using a radiometer with a wavelength of 400-500 nm and a light intensity measurement capacity of up to 3 500 mw/cm2. Intensity below 400 mw/cm2 was recorded as low, from 400 to 800 mw/cm2 as medium, from 800 a 1 200 mw/cm2 as high and above 1 200 mw/cm2 as very high. Results: Intensity was medium in 48.5 percent of the lamps analyzed, high in 22.86 percent, low in 15.71 percent and very high in 12.86 percent. A lower frequency of lamps with greater clinical use was reported. Conclusions: The LED light curing lamps used in dental offices of the province of Piura during the year 2020 emit an average output intensity of 778.14 mW/cm2, which corresponds to medium intensity(AU)

Spin Wave Electromagnetic Nano-Antenna Enabled by Tripartite Phonon-Magnon-Photon Coupling.

Tripartite coupling between phonons, magnons, and photons in a periodic array of elliptical magnetostrictive nanomagnets delineated on a piezoelectric substrate to form a 2D two-phase multiferroic crystal is investigated. Surface acoustic waves (SAW) (phonons) of 5-35 GHz frequency launched into the substrate cause the magnetizations of the nanomagnets to precess at the frequency of the wave, giving rise to confined spin-wave modes (magnons) within the nanomagnets. The spin waves, in turn, radiate electromagnetic waves (photons) into the surrounding space at the SAW frequency. Here, the phonons couple into magnons, which then couple into photons. This tripartite phonon-magnon-photon coupling is thus exploited to implement an extreme sub-wavelength electromagnetic antenna whose measured radiation efficiency and antenna gain exceed the approximate theoretical limits for traditional antennas of the same dimensions by more than two orders of magnitude at some frequencies. Micro-magnetic simulations are in excellent agreement with experimental observations and provide insight into the spin-wave modes that couple into radiating electromagnetic modes to implement the antenna.

In situ thermal modification of kafirin using infrared radiations and microwaves.

BACKGROUND: Kafirin is a prolamin protein located in the corneous endosperm of sorghum. The conventional thermal processing of kafirin reduces its solubility, which limits its utilization in the food industry. Therefore, the study was aimed to investigate the effect of in situ thermal modification of kafirin using two different electromagnetic thermal treatments, namely infrared (IR) and microwave (MW) radiation, on the physicochemical, structural, thermal, and antioxidant properties. RESULTS: The results demonstrated that both the thermal modifications improved yield, purity, and solubility of the kafirin with a decrease in hydrophobicity. However, IR-treated samples showed higher solubility (910.67 g kg-1 ) and lower hydrophobicity (387.67). The IR modifications also improved the ratio of α helix/ß sheets to a great extent. The alterations in the disulfide content were concomitant with the improvement in the thermal stability of kafirin. Sodium dodecyl sulfate polyacrylamide gel electrophoresis showed variations in the band intensities of ß- and γ-kafirin, indicating alterations in the kafirin subunits. Morphological examination of kafirin revealed surface withering and agglomeration. Notably, IR treatment improved the antioxidant activity more efficiently (from 32.11% to 74.05%). CONCLUSION: Although both the IR and MW treatments modified kafirin, the effect seemed to be more pronounced in IR modification. The IR-modified kafirin had better solubility and lesser hydrophobicity than MW-modified kafirin. The physicochemical and structural changes induced by IR treatment improved the biological activity of kafirin, in terms of antioxidant activity. Therefore, it was concluded that the in situ IR modification of kafirin can alter its characteristic properties, improving its potential as a food ingredient. © 2021 Society of Chemical Industry.

Transient analysis of power loss density with time-harmonic electromagnetic waves in Debye media.

Due to the complex permittivity, it is difficult to directly clarify the transient mechanism between electromagnetic waves and Debye media. To overcome the above problem, the temporal relationship between the electromagnetic waves and permittivity is explicitly derived by applying the Fourier inversion and introducing the remnant displacement. With the help of the Poynting theorem and energy conservation equation, the transient power loss density is derived to describe the transient dissipation of electromagnetic field and the mechanism on phase displacement has been explicitly revealed. Besides, the unique solution can be obtained by applying the time-domain analysis method rather than involving the frequency-domain characteristics. The effectiveness of transient analysis is demonstrated by giving a comparison simulation on one-dimensional example.

Far-Field Subwavelength Straight-Line Projection/Imaging by Means of a Novel Double-Near-Zero Index-Based Two-Layer Metamaterial.

In this paper, for the first time, tuned near-zero-index materials are used in a structure for the long-distance projection of very closely spaced objects with subwavelength separation. Near-zero-index materials have never been used for subwavelength projection/imaging. The proposed novel structure is composed of a two-layer slab that can project two slits with a subwavelength separation distance to a long distance without diverged/converged interference of the two imaged waves. The two-layer slab consists of a thin double-near-zero (DNZ) slab with an obtained tuned index of 0.05 and thickness of 0.04λ0 coupled with a high-index dielectric slab with specific thicknesses. Through a parametric study, the non-zero index of the DNZ layer is tuned to create a clear image when it is coupled with the high-index dielectric layer. The minimum size for the aperture of the proposed two-layer slab is 2λ0 to provide a clear projection of the two slits. The space between the slits is λ0/8, which is five times beyond the diffraction limit. It is shown that, through the conventional methods (e.g., only with high-index dielectric slabs, uncoupled with a DNZ layer), it is impossible to clearly project slits at a large distance (~λ0) due to the diffraction limit. An analytical analysis, as well as numerical results in a finite-element-based simulator, confirm the function of the proposed structure.

In Vitro and In Vivo Enhancement of Temozolomide Effect in Human Glioblastoma by Non-Invasive Application of Cold Atmospheric Plasma.

Glioblastoma (GBM) is one of the most aggressive forms of adult brain cancers and is highly resistant to treatment, with a median survival of 12-18 months after diagnosis. The poor survival is due to its infiltrative pattern of invasion into the normal brain parenchyma, the diffuse nature of its growth, and its ability to quickly grow, spread, and relapse. Temozolomide is a well-known FDA-approved alkylating chemotherapy agent used for the treatment of high-grade malignant gliomas, and it has been shown to improve overall survival. However, in most cases, the tumor relapses. In recent years, CAP has been used as an emerging technology for cancer therapy. The purpose of this study was to implement a combination therapy of CAP and TMZ to enhance the effect of TMZ and apparently sensitize GBMs. In vitro evaluations in TMZ-sensitive and resistant GBM cell lines established a CAP chemotherapy enhancement and potential sensitization effect across various ranges of CAP jet application. This was further supported with in vivo findings demonstrating that a single CAP jet applied non-invasively through the skull potentially sensitizes GBM to subsequent treatment with TMZ. Gene functional enrichment analysis further demonstrated that co-treatment with CAP and TMZ resulted in a downregulation of cell cycle pathway genes. These observations indicate that CAP can be potentially useful in sensitizing GBM to chemotherapy and for the treatment of glioblastoma as a non-invasive translational therapy.