Non-thermal Microwave Radiation Research Articles

Denaturation of the SARS-CoV-2 spike protein under non-thermal microwave radiation

SARS-CoV-2, the virus that causes COVID-19, is still a widespread threat to society. The spike protein of this virus facilitates viral entry into the host cell. Here, the denaturation of the S1 subunit of this spike protein by 2.45 GHz electromagnetic radiation was studied quantitatively. The study only pertains to the pure electromagnetic effects by eliminating the bulk heating effect of the microwave radiation in an innovative setup that is capable of controlling the temperature of the sample at any desired intensity of the electromagnetic field. This study was performed at the internal human body temperature, 37 °C, for a relatively short amount of time under a high-power electromagnetic field. The results showed that irradiating the protein with a 700 W, 2.45 GHz electromagnetic field for 2 min can denature the protein to around 95%. In comparison, this is comparable to thermal denaturation at 75 °C for 40 min. Electromagnetic denaturation of the proteins of the virus may open doors to potential therapeutic or sanitation applications.

Influence of non-thermal microwave radiation on emulsifying properties of sunflower protein

Sunflower protein isolate obtained from industrially de-oiled press cake was treated with non-thermal microwave, aiming to investigate how structure and emulsifying properties were affected. Our results indicated that the content of polar amino acids was decreased and solubility and surface hydrophobicity were altered upon exposure to non-thermal microwave. Higher solubility and surface hydrophobicity of the samples treated with defrost mode and also 350 W were accompanied by a smaller size and lower uniformity of the oil droplets compared to the control and other samples. Non-thermal microwave treatment improved the emulsion stability by 1.43 times and defrost mode treated sample had the lowest stability index after 120 min. Interfacial dilatational rheology measurements revealed that 70 and 350 W treated samples created higher elastic, less stretchable solid-like layer at the O/W interface in comparison with defrost mode treated and control samples. Consequently, non-thermal microwave treatment could be considered as a promising simple, fast, and “green” protein modification technique.

Acoustic assessment of pulmonary ventilation in children with bronchial asthma on the background of a single exposure to microwave radiation

Summary. Diseases of the respiratory organs of children, occurring with obstructive syndrome, represent one of the most serious problems in terms of transition to chronic forms. The chronic process is accompanied by a decrease in pulmonary ventilation, which leads to the search for effective methods of complex therapy of diseases.
 The purpose of this study was to evaluate the dynamics of acoustic indicators of pulmonary ventilation in children with bronchial asthma, against the background of non-invasive non-thermal microwave radiation.
 Materials and methods. 122 children with bronchial asthma aged from 3 to 17 years were examined. 113 patients underwent a single session of non-invasive microwave therapy with the Aster device. Comparison of acoustic characteristics of pulmonary ventilation was carried out taking into account the severity of the disease and the age of children with bronchial asthma. Acoustic assessment of ventilation function was performed using the computer bronchophonography complex Pattern-01 before the Aster procedure, after 5 and 15 minutes. In 20 (16.4%) patients with bronchial asthma, the dynamics of cough was evaluated against the background of Aster therapy for 7 days.
 Results. Improvement of bronchial patency was registered in all age groups with mild bronchial asthma. In the group of moderate asthma, exposure to electromagnetic radiation led to a significant reduction in ventilation disorders in children aged 711 years. As patients grow older, as well as with severe bronchial asthma, the smallest dynamics of the parameters of pulmonary ventilation was observed against the background of Aster therapy. The use of electromagnetic radiation in addition to traditional basic therapy for 7 days leads to a faster regression of cough in patients with bronchial asthma.
 Conclusion. The combination of traditional basic therapy with electromagnetic non-thermal radiation in patients with bronchial asthma reduces obstructive pulmonary ventilation disorders and promotes faster cough regression.

Runaway electron studies with hard x-ray and microwave diagnostics in the FT-2 lower hybrid current drive discharges

Studies of the super-thermal and runaway electron behavior in ohmic and lower hybrid current drive FT-2 tokamak plasmas have been carried out using information obtained from measurements of hard x-ray spectra and non-thermal microwave radiation intensity at the frequency of 10 GHz and in the range of (53 ÷ 78) GHz. A gamma-ray spectrometer based on a scintillation detector with a LaBr3(Ce) crystal was used, which provides measurements at counting rates up to 107 s−1. Reconstruction of the energy distribution of RE interacting with the poloidal limiter of the tokamak chamber was made with application of the DeGaSum code. Super-thermal electrons accelerated up to 2 MeV by the LH waves at the high-frequency pumping of the plasma with low density ~ 2 × 1013 cm−3 and then up to 7 MeV by vortex electric field have been found. Experimental analysis of the runaway electron beam generation and evolution of their energy distribution in the FT-2 plasmas is presented in the article and compared with the numerical calculation of the maximum energy gained by runaway electrons for given plasma parameters. In addition, possible mechanisms for limiting the maximum energy gained by the runaway electrons are also calculated and described for a FT-2 plasma discharge.

Mechanisms and possibilities of defect reorganization in III–V compounds due to the non-thermal microwave radiation treatment

The influence of microwave radiation (2.45GHz) treatment on processes of reorganization and generation of defects in epitaxial films of GaN and GaAs has been studied. Physical reasons of the observed transformations caused by specific non-thermal action of microwave radiation have been analyzed. Long-term processes of structural transformation after microwave radiation treatment have been modeled. Our approximation is based on the assumption that evolution processes in the defect subsystem, in the crystal are random events, and distribution of the random value – the time before a random event – is a subject to the Weibull-Gnedenko law. Qualitative and quantitative agreements between experimental data and theoretical models of long-term structural changes caused by microwave treatment have been obtained. These results enable to explain non-monotonous behavior of photoluminescence spectra after microwave treatment and could be applied to prediction the consequences of non-thermal action of microwave radiation.

Nonthermal Microwave Emission Features under the Plasma Ohmic Heating and Low-hybrid Current Drive in the FT - 2 Tokamak

Study of behavior of accelerated electrons (AE) in the ohmically heated (OH) plasma and low-hybrid current drive (LHCD) in tokamak has the practical interest especially for estimations of AE radiation energy losses and solving of the non-inductive CD problem for the ITER. Studies based on measurements of non-thermal microwave radiation (MR) intensity and hard X-ray (HXR) spectra are conducted in the FT-2 tokamak having large local magnetic ripples under LHCD in the omically heated (OH) plasma with the fan instability excited. The paper presents experimental data first obtained in such conditions witnessing about some AE behavior features. Nature of MR abnormal intensity and short giant flashes together with the fast additional electron heating in the plasma core are discussed. The first high additional fast electron heating was registered together with the synchrotron radiation (SR) intensity increase. It was accompanied by short MR spikes observed in the narrow frequency range (53 ÷ 78) GHz. They arise owing to the AE transverse energy and pitch angle increase under each crossing the cyclotron auto-resonance region and SR maser gain. It is proposed the heating mechanism owing to absorption of SR and Bernstein waves arising at linear transformation the extraordinary component of intensive MR spikes in the black plasma layers. It was found that the non-thermal MR of abnormal intensity arising during OH in the frequency range (10 ÷ 40) GHz is due to the fan instability development and the substantial local magnetic ripples. MR is accompanied by short giant flashes having a narrow frequency spectrum. Together with the SR growth the less intensive MR flashes appear in the range (57 ÷ 75) GHz. In our case it becomes possible the maser amplification of both SR and collective radiation. Appearance of the giant flashes may be initiated under transition of the maser - amplifier into the self - excitation regime, when low-frequency quasi- coherent MR flashes are generated.

Biomarkers in volunteers exposed to mobile phone radiation

For some time it has been investigated whether low-intensity non-thermal microwave radiation from mobile phones adversely affects the mammalian blood–brain barrier (BBB). All such studies except one have been either in vitro or experimental animal studies. The one carried out on humans showed a statistically significant increase in serum transthyretin (TTR) 60min after finishing of a 30-min microwave exposure session. The aim of the present study was to follow up on the finding of the previous one using a better study design. Using biomarkers analyzed in blood serum before and after the exposure this single blinded randomized counterbalanced study, including 24 healthy subjects aged 18–30 years that all underwent three exposure conditions (SAR10G=2W/kg, SAR10G=0.2W/kg, sham), tested whether microwaves from an 890-MHz phone-like signal give acute effects on the integrity of brain-shielding barriers. Over time, statistically significant variations were found for two of the three biomarkers (TTR; β-trace protein); however, no such difference was found between the different exposure conditions nor was there any interaction between exposure condition and time of blood sampling. In conclusion this study failed to show any acute clinically or statistically significant effect of short term microwave exposure on the serum levels of S100β, TTR and β-trace protein with a follow up limited to two hours. The study was hampered by the fact that all study persons were regular wireless phone users and thus not naïve as to microwave exposure.

A New Sterilization Technique of Bovine Pericardial Biomaterial Using Microwave Radiation

Bioprosthetic valves created from chemically treated natural tissues such as bovine pericardial biomaterial are used as heart valve scaffolds. Methods currently available for sterilization of biomaterial for transplantation include the application of gamma radiation and chemical sterilants. These techniques, however, can be problematic because they can be expensive and lead to a reduction in tissue integrity. Therefore, improved techniques are needed that are cost effective and do not disrupt the physical properties, functionality, and lifespan of the valvular leaflets. This study examined a novel technique using nonthermal microwave radiation that could lead to the inactivation of bacteria in bovine pericardial biomaterial without compromising valve durability. Two common pathogenic species of bacteria, Escherichia coli and Staphylococcus aureus, were used as test microorganisms. Optimized microwave parameters were used to determine whether inactivation of pathogenic bacteria from bovine pericardium could be achieved. In addition, the effect of microwave sterilization on tissue integrity was examined. The mechanical properties (assessed using dynamic mechanical analysis) and tensile strength testing (using a Universal Tensile Tester) as well as thermal analysis (using thermogravimetric analysis and differential scanning calorimetry) indicated that microwave sterilization did not compromise the functionality of bovine pericardial biomaterial. Scanning electron microscopy imaging and cytotoxicity testing also confirmed that the structure and biocompatibility of transplant biomaterial remained unaltered after the sterilization process. Results from the application of this new microwave (MW) sterilization technique to bovine pericardium showed that near-complete inactivation of the contaminant bacteria was achieved. It is concluded that nonthermal inactivation of pathogenic bacteria from bovine pericardial biomaterial could be achieved using microwave radiation.

Exposure to an 890-MHz mobile phone-like signal and serum levels of S100B and transthyretin in volunteers

Whether low-intensity non-thermal microwave radiation alters the integrity of the blood-brain barrier has been debated since the late 1970s, yet no experimental study has been carried out on humans. The aim of this study was to test, using peripheral markers, whether exposure to a mobile phone-like signal alters the integrity of the human blood-brain and blood-cerebrospinal fluid barriers. A provocation study was carried out that exposed 41 volunteers to a 30 min GSM 890 MHz signal with an average specific energy absorption rate distribution of 1.0 W/kg in the temporal area of the head as measured over any 1g of contiguous tissue. The outcome was assessed by changes in serum concentrations of two putative markers of brain barrier integrity, S100B and transthyretin. Repeated blood sampling before and after the provocation showed no statistically significant increase in the serum levels of S100B, while for transthyretin a statistically significant increase was seen in the final blood sample 60 min after the end of the provocation as compared to the prior sample taken immediately after provocation (p=0.02). The clinical significance of this finding, if any, is unknown. Further randomized studies with use of additional more brain specific markers are needed.

Non-Thermal Radiation at Runaway Electron Instability

Non-thermal microwave radiation from a tokamak NOVA \(\varPi\) operated in a runaway mode exhibited two distinct time behaviors at X-band synchronized with the positive spikes in loop voltage, depending on the vertical magnetic field. One can be explained by synchrotron radiation through the pitch angle scattering of the runaways. The other is closely related with the ratio ω c e /ω p e .

Microwave radiation from an electrodeless induction discharge

The results are described of an investigation of non-thermal microwave radiation from the plasma of an electrodeless induction discharge. A correlation between the microwave and the X-ray radiation is established. The microwave radiation appears at the instant of formation of the critical density in the plasma, for the frequency of detection. A suggestion is made concerning the appearance in the plasma of a beam instability, leading to the excitation of electron plasma oscillations which become transformed into transverse electromagnetic waves.

Non-thermal microwave radiation from Jupiter.

Non-thermal microwave radiation from Jupiter.