Low-level Microwave Radiation Research Articles

Long-Term, Low-Level Microwave Radiation Impairs Learning and Memory via Synbindin: Molecular Basis and Underlying Mechanism

Long-Term, Low-Level Microwave Radiation Impairs Learning and Memory via Synbindin: Molecular Basis and Underlying Mechanism

Bacterial Disinfection of Polymethyl Methacrylate (PMMA) Resin Polymer Using Low Level Microwave Irradiation and Denture Cleaning Agent

The aim was to evaluate the disinfection of E. coli, S. aureus and S. mutans cultured on Polymethyl Methacrylate (PMMA) resin polymer using microwave disinfection and sodium perborate (DC). Biofilms of E. coli, S. aureus and S. mutans were cultured on the PMMA denture base for 24, 36, 48 and 96 h. Specimens were subjected to three disinfection protocols, including microwave disinfection in distilled water (MW-DW), sodium perborate (denture cleaning tablet) with distilled water (DC-DW) and a combination of MW-DC-DW for 1 to 5 min. Colony-forming units among the study groups were analyzed using Kruskal–Wallis and Mann–Whitney tests. For E. coli and S. aureus cultured on PMMA, the MW-DC-DW group displayed complete disinfection at 2 min of exposure. However, for both bacteria, the MW-DW disinfection group showed zero CFU at 3 min. DC disinfection for E. coli and S. aureus displayed zero CFU at 5 min of exposure (p ≤ 0.05). For S. mutans, MW-DC-DW and MW-DW displayed zero CFU count at 1 min and 2 min, respectively. In DC-treated samples, CFU were significantly zero at 4 min when compared with the control at each growth time. A combination of MW irradiation with DC (sodium perborate) showed higher disinfection percentage of bacterial species on PMMA polymer denture bases compared to MW and DC alone. PMMA disinfection using DC displayed a lower antimicrobial disinfection percentage than the combined use of MW and DC as well as MW alone at 1 min or 2 min disinfection for E. coli, S. aureus and S. mutans.

Effects of silica-rich water on systemic and peritoneal inflammation in rats exposed to chronic low-level (900-MHz) microwave radiation.

Immunomodulating effect of silica-rich water represents a novel field for research, especially regarding its features toward environmental pollutants. The aim of our study was to evaluate the effects of silica-rich water intake on systemic and peritoneal inflammation in rats that were chronically exposed to the low-level microwave (MW) radiation from mobile phones. Wistar Albino rats were exposed to 900 MHz MW radiation for 3 months. The four-treatment model involved rats with standard water (SW) or experimental silica-rich water intake (EW). Peritoneal macrophages (PMs) were harvested using peritoneal lavage and divided into non-stimulated and lipopolysaccharide (LPS) stimulated subgroups. The MW-exposed rats with silica-rich water (MW+EW) had lower serum tumor necrosis factor α (TNF-α) and interleukin 2 (IL-2) levels, but higher IL-10 levels, than MW+SW rats (p < 0.05). The higher TNF-α production by non-stimulated MW exposed PMs was ameliorated by the silica-rich water (p < 0.01). The MW exposition suppressed LPS potential for TNF-α synthesis in both water type groups, with greater suppression in animals that took standard water. Our results show the modulating effect of silica-rich water toward MW-induced systemic and peritoneal inflammation, which reflects the water ability to shape monocyte plasticity, thereby altering the balance between their proinflammatory and anti-inflammatory properties.

Microwave plasma enhancement of multiphase flames: On-demand control of solid propellant burning rate

This effort explores the microwave-supported plasma enhancement of an aluminized, ammonium perchlorate composite solid propellant flame. The technique is enabled through novel alkali metal doping, which provides increased levels of ionization and allows efficient microwave energy deposition to the flame structure and subsequent perturbation of the steady-state propellant burning rate. Three potential modes of energy deposition are identified in composite propellants: (1) plasma-enhancement promoted by the presence of sodium, (2) strong absorption by high temperature metallic oxide products, and (3) direct absorption of energy by the propellant burning surface condensed phase. Equilibrium calculations are used to identify propellant compositions with high free-electron populations, and solution of the Boltzmann equation using the BOLSIG + code is used to show the significant effects of sodium doping on microwave absorption of the flame. Experimental emission spectroscopy and imaging of the microwave-enhanced propellant flame structure show evidence of these mechanisms. Propellant burning rates can be increased by up to 60% through the application of 1 kW, continuous 2.46 GHz microwave radiation. Propellant doping with 3.5% by weight of sodium nitrate shows significant improvement in the effectiveness of microwave application in modifying the propellant burning rate. This technique provides high levels of dynamic propellant combustion control from a solid-state system. The on-demand control of energetic material burning rates through low level doping and microwave irradiation is a promising technique which could lead to the development of a new class of ‘smart’ dynamically controllable energetic materials.

Effect of Low Level Subchronic Microwave Radiation on Rat Brain

ObjectiveThe present study was designed to investigate the effects of subchronic low level microwave radiation (MWR) on cognitive function, heat shock protein 70 (HSP70) level and DNA damage in brain of Fischer rats. MethodsExperiments were performed on male Fischer rats exposed to microwave radiation for 90 days at three different frequencies: 900, 1800, and 2450 MHz. Animals were divided into 4 groups: Group I: Sham exposed, Group II: animals exposed to microwave radiation at 900 MHz and specific absorption rate (SAR) 5.953 × 10−4 W/kg, Group III: animals exposed to 1800 MHz at SAR 5.835 × 10−4 W/kg and Group IV: animals exposed to 2450 MHz at SAR 6.672 × 10−4 W/kg. All the animals were tested for cognitive function using elevated plus maze and Morris water maze at the end of the exposure period and subsequently sacrificed to collect brain tissues. HSP70 levels were estimated by ELISA and DNA damage was assessed using alkaline comet assay. ResultsMicrowave exposure at 900–900–2450 MHz with SAR values as mentioned above lead to decline in cognitive function, increase in HSP70 level and DNA damage in brain. ConclusionThe results of the present study suggest that low level microwave exposure at frequencies 900, 1800, and 2450 MHz may lead to hazardous effects on brain.

Mechanism of low-level microwave radiation effect on nervous system

ABSTRACTThe aim of this study is to explain the mechanism of the effect of low-level modulated microwave radiation on brain bioelectrical oscillations. The proposed model of excitation by low-level microwave radiation bases on the influence of water polarization on hydrogen bonding forces between water molecules, caused by this the enhancement of diffusion and consequences on neurotransmitters transit time and neuron resting potential. Modulated microwave radiation causes periodic alteration of the neurophysiologic parameters and parametric excitation of brain bioelectric oscillations. The experiments to detect logical outcome of the mechanism on physiological level were carried out on 15 human volunteers. The 450-MHz microwave radiation modulated at 7, 40 and 1000 Hz frequencies was applied at the field power density of 0.16 mW/cm2. A relative change in the EEG power with and without radiation during 10 cycles was used as a quantitative measure. Experimental data demonstrated that modulated at 40 Hz microwave radiation enhanced EEG power in EEG alpha and beta frequency bands. No significant alterations were detected at 7 and 1000 Hz modulation frequencies. These results are in good agreement with the theory of parametric excitation of the brain bioelectric oscillations caused by the periodic alteration of neurophysiologic parameters and support the proposed mechanism. The proposed theoretical framework has been shown to predict the results of experimental study. The suggested mechanism, free of the restrictions related to field strength or time constant, is the first one providing explanation of low-level microwave radiation effects.

Plant irradiation device in microwave field with controlled environment

Plant irradiation during the germination period, by using environmental low level microwave radiation (known as electrosmog) alters the plant germination and the growing process. In order to analyze if such a subtle effect is generated only by the microwave irradiation, the environmental parameters (light, temperature, and humidity) must be kept identical for the reference and the irradiated lot. This is a difficult task because the humidity and temperature are interrelated. In order to study the plant behavior under microwaves low power irradiation, the paper describes the design, manufacturing and operating process and device performances on plant growth. To this end, a low power microwave field (average microwaves power density of 3.8mW/m2) under controlled environmental parameters is used. The device consists of a reference chamber (R) and a microwave irradiation chamber (I), of 0.5m3 volume each one, equipped with access doors. The irradiation chamber ensures microwave field distribution with programmable power, frequency and bandwidth in the most commonly used standards for network communication such as: Global System for Mobile Communications (GSM900/1800), Code Division Multiple Access (CDMA), the third generation of mobile telecommunications technology (3G) or 2.4/5GHz Wireless Local Area Network (WLAN). Both chambers provide a radiofrequency (RF) shielding (at least −60dB) against and toward outside, so the electrosmog is shielded and does not interfere with the inner environment. Both chambers are equipped with performing temperature/humidity sensors and controlled LED lighting system (maximum 400μmolcm−2s−1) with a uniformity of ±5μmolcm−2s−1 measured at the bottom level of the chamber. An embedded system (microcontroller) measures the temperature and humidity and proceeds continuously to match the humidity into the chambers pair with less than ±1.5% relative humidity (RH) difference, by using a low flux exhaust ventilation process through a simple innovative method. The accuracy of the temperature measurement is better than ±0.2°C. Humidity and temperature data set are logged (with programmable acquisition rate) during the whole experiment and can be read later by a personal computer. To identify the influence of microwave treatment on bean seeds and plants development, three growing experiments were settled, based on 122 bean seeds each. The number of germinated seeds (determined each day during 8days of experiment), the germination energy (GE [%]) of the seeds, the length of stems (SL) and roots (RL), the germination (G) [%], the seedling vigor index (SVI) and dry matter content (DM%) have been measured and computed. The obtained data showed significant increase for all parameters on microwave irradiation condition.

Detection of low level microwave radiation induced deoxyribonucleic acid damage vis-à-vis genotoxicity in brain of fischer rats

Background:Non-ionizing radiofrequency radiation has been increasingly used in industry, commerce, medicine and especially in mobile phone technology and has become a matter of serious concern in present time.Objective:The present study was designed to investigate the possible deoxyribonucleic acid (DNA) damaging effects of low-level microwave radiation in brain of Fischer rats.Materials and Methods:Experiments were performed on male Fischer rats exposed to microwave radiation for 30 days at three different frequencies: 900, 1800 and 2450 MHz. Animals were divided into 4 groups: Group I (Sham exposed): Animals not exposed to microwave radiation but kept under same conditions as that of other groups, Group II: Animals exposed to microwave radiation at frequency 900 MHz at specific absorption rate (SAR) 5.953 × 10−4 W/kg, Group III: Animals exposed to 1800 MHz at SAR 5.835 × 10−4 W/kg and Group IV: Animals exposed to 2450 MHz at SAR 6.672 × 10−4 W/kg. At the end of the exposure period animals were sacrificed immediately and DNA damage in brain tissue was assessed using alkaline comet assay.Results:In the present study, we demonstrated DNA damaging effects of low level microwave radiation in brain.Conclusion:We concluded that low SAR microwave radiation exposure at these frequencies may induce DNA strand breaks in brain tissue.

Enzymatic alterations in developing rat brain cells exposed to a low-intensity 16.5 GHz microwave radiation

The present study deals with the effects of chronic exposure of low-level microwave radiation on developing rat brain. Starting at 35 days of age, male rats were exposed to 2 h/day for another 35 days to a 16.5-GHz microwave radiation field. After the exposure period, the rats were sacrificed, and brain tissues dissected out and used for biochemical assay. Results showed that exposure to a 16.5-GHz radiation caused significant changes in the activity of protein kinase C as compared to the control group. Furthermore, electron microscopic study revealed an increase in glial cell population. These results confirm that brain cell membrane is an interactive site for electromagnetic field causing an inflammation and possibly tumor promotion.

Low power microwave‐assisted enzymatic esterification of starch

AbstractA series of starch esters was obtained using microwave‐assisted enzymatic transformation of starch. For the reaction hog pancreas lipase was used as a biocatalyst as well as followed acyl donors: acetic, lauric, and stearic acid. DMF and DMSO were applied as a reaction media. Experiments focused on low level microwave irradiation were compared with conventional heating of the reaction mixture. The structure of obtained starch esters was investigated by means of FTIR, analysis of substitution degree, changes in molecular parameters (MWs and MWs distributions), and microscopic studies (SEM). The spectroscopic analysis confirmed the ester bond formation. The microwave‐assisted reaction in DMF and lauric acid as an acyl donor, gave the highest degree of substitution (0.513) what followed the lowest polysaccharide degradation and maintaining the granular structure of starch. According to all the results the significant shortening in the reaction time (about 2.5 times) for microwave‐assisted reactions were observed. The influence of microwaves on esterification of starch was discussed focusing on reaction media and acyl donor type. The investigated reaction systems were demonstrated as new protocols for obtaining starch ester with higher efficiency in comparison to those known as conventional. Replacement of sophisticated derivatives including vinyl esters or acyl chlorides by simple acyl donors were shown as an additional benefit of proposed starch esterification method.

Effects of microwaves on the puffing pattern of D. melanogaster

Abstract The influence of electromagnetic field exposure on puffing pattern of salivary gland polythene chromosomes, viability and fertility of Drosophila melanogaster of the wild type Canton-S line was studied. Experimental conditions: Electromagnetic field characteristics: frequency — 36.64 GHz, power density — 0.4 W/m2, exposure time −10 seconds. Electromagnetic field exposure was conducted on the egg stage. Results: in larvae developed from the exposed eggs 3 of 8 chromosomal puffs tested (71CE, 82EF, and 83E) had significantly smaller dimensions than these in control at the prepupal stage. Viability of Drosophila estimated by the number of adult flies hatched from exposed eggs decreased, while the number of dominant lethal mutations increased. Conclusion: the exposure to a low-level microwave irradiation suppressed puffing activity at ecdysone-inducible loci of Drosophila polythene chromosomes, increased frequency of dominant lethal mutations and decreased Drosophila viability but did not influence Drosophila fertility.

Effects of low level microwave radiation on carcinogenesis in Swiss Albino mice

This study concerns with the multiple treatment of the target site to potent carcinogen and the super imposition of low level radiofrequency and microwave radiation. Swiss albino mice (male) were used for this investigation. The study has been divided in two parts, part A: a single dose of 7,12-dimethylbenz(a)anthracene (DMBA) 100 μg/animal was applied topically on the skin of mice and were exposed to 112 MHz amplitude modulated (AM) at 16 Hz (power density 1.0 mW/cm(2), specific absorption rate (SAR) 0.75 W/kg). Similarly after a single dose of DMBA, mice were exposed to 2.45 GHz radiation (power density of 0.34 mW/cm(2), SAR, 0.1 W/kg), 2 h/day, 3 days a week for a period of 16 weeks. The two sets of experiments were carried out separately. Part B: mice were transplanted intraperitoneally (ip) with ascites 8 × 10(8) (Ehrlich-Lettre ascites, strain E) carcinoma cells per mouse. These mice were exposed to 112 MHz amplitude modulated at 16 Hz and 2.45 GHz radiation separately for a period of 14 days. There was no tumor development in mice exposed to RF and MW. Similarly a topical application of single dose of DMBA followed by RF/MW exposure also did not produce any visible extra tumor on the skin of mice. On the other hand mice were transplanted intraperitoneally with ascites (8 × 10(8) cell/ml) and subsequently exposed to above mentioned fields for 14 days showed a slight increase in the cell numbers as compared to the control group. However, the increase is insignificant. There were insignificant differences either in the mortality or cell proliferation among the control and exposed group. This results show that low level RF or MW do not alter tumor growth and development as evidenced by no observable change in tumor size.

Effect of modulated at different low frequencies microwave radiation on human EEG

This study is aimed to clarify whether effect of low-level microwave radiation on human brain differs at different modulation frequencies. Resting EEG recordings were done on different groups of healthy volunteers. The 450 MHz microwave radiation modulated at 40 and 70 Hz (15 subjects) and 217 and 1,000 Hz (19 subjects) fre- quencies was applied. The results of our previous study at 7, 14 and 21 Hz modulation were included into analysis. Ten cycles of the exposure (1 min off and 1 min on) at each fixed modulation frequencies were applied. The field power density at the scalp was always 0.16 mW/cm 2 . Our results showed that microwave exposure increased the EEG energy at EEG frequencies lower or close to the modula- tion frequency. No effect was detected at EEG frequencies higher than the modulation frequency. Statistically signif- icant changes were caused by exposure in the EEG alpha and beta frequency bands; no significant effect was detected in the theta band. Our results suggest that tele- communication devices with complex spectrum of modulation frequencies like mobile phone can affect all human EEG frequency bands.

The influence of differently polarised microwave radiation on chromatin in human cells

Purpose: To determine the possible biological effects of differently polarised microwave radiation on the chromatin state in human cells.Materials and methods: Isolated human buccal epithelium cells were irradiated by microwaves of frequency f = 35 GHz and surface power density E = 30 μW/cm2. The state of chromatin in human cells was determined by methods of light and electron microscopy. The state of cell membranes was evaluated by the method of vital indigo carmine staining.Results: The microwave-induced condensation of chromatin in human cells is revealed. Degree of microwave-induced condensation depends on the state of polarisation of electromagnetic wave: In some cases left circularly polarised waves induce less effect than linearly polarised radiation. The linearly polarised electromagnetic waves induce cell membrane damage revealed by increase of cell staining. The data obtained are discussed in connection with mechanisms of biological effects of electromagnetic fields.Conclusion: The data obtained in this work demonstrate important biological effects of monochromatic microwave irradiation at 35 GHz. Low-level microwave irradiation induces chromatin condensation in human cells and damages of cell membranes.

Exposure of Cultured Astroglial and Microglial Brain Cells to 900 MHz Microwave Radiation

The rapid rise in the use of mobile communications has raised concerns about health issues related to low-level microwave radiation. The head and brain are usually the most exposed targets in mobile phone users. In the brain, two types of glial cells, the astroglial and the microglial cells, are interesting in the context of biological effects from microwave exposure. These cells are widely distributed in the brain and are directly involved in the response to brain damage as well as in the development of brain cancer. The aim of the present study was to investigate whether 900 MHz radiation could affect these two different glial cell types in culture by studying markers for damage-related processes in the cells. Primary cultures enriched in astroglial cells were exposed to 900 MHz microwave radiation in a temperature-controlled exposure system at specific absorption rates (SARs) of 3 W/kg GSM modulated wave (mw) for 4, 8 and 24 h or 27 W/kg continuous wave (cw) for 24 h, and the release into the extracellular medium of the two pro-inflammatory cytokines interleukin 6 (Il6) and tumor necrosis factor-alpha (Tnfa) was analyzed. In addition, levels of the astroglial cell-specific reactive marker glial fibrillary acidic protein (Gfap), whose expression dynamics is different from that of cytokines, were measured in astroglial cultures and in astroglial cell-conditioned cell culture medium at SARs of 27 and 54 W/kg (cw) for 4 or 24 h. No significant differences could be detected for any of the parameters studied at any time and for any of the radiation characteristics. Total protein levels remained constant during the experiments. Microglial cell cultures were exposed to 900 MHz radiation at an SAR of 3 W/kg (mw) for 8 h, and I16, Tnfa, total protein and the microglial reactivity marker ED-1 (a macrophage activation antigen) were measured. No significant differences were found. The morphology of the cultured astroglial cells and microglia was studied and appeared to be unaffected by microwave irradiation. Thus this study does not provide evidence for any effect of the microwave radiation used on damage-related factors in glial cells in culture.

Instabilities in the current-voltage characteristics of submicron BSCCO bridges

The influence of magnetic field and microwave irradiation on dynamical phase separation in submicron Bi2Sr2CaCu2O8+x bridges has been studied. Strong effect on the shape and metastable character of the step-like I-V characteristics are found. Under a weak field H < 2 Oe and low level microwave irradiation the step-like structure of the I-V characteristics smears out and disappears completely. The average frequency of switching between metastable states grows by 5 orders under increase of magnetic field by only 1 Oe. This behavior is explained in terms of the model of dynamical vortex lines.

Low-Level Microwave Radiation Effect on Nerve Pulse Conduction Velocity

This study is aimed to investigate dependence of nerve pulse conduction velocity on low-level microwave exposure. The changes in fiber membrane permeability or myelin sheath, caused by microwave, should affect nerve pulse conduction velocity. Experimental investigation was carried out for nerve pulse conduction velocity with and without applied microwave field and different orientations of its polarization to the nerve fiber. Microwave radiation of 450 MHz was applied polarized perpendicular or parallel to the nerve fiber. The measured field power density at the skin was 0.87 mW/cm2. Special program was developed for calculation of the nerve pulse conduction velocity in LabView environment. The right nervus medianus motor nerve fibers of 35 young subjects were under the study. The experimental protocol included ten measurements in every cycle of five different exposure conditions. No changes in average values of the conduction velocities discovered in different exposure conditions. Theoretical calculations based on Hodgkin-Huxley model confirm only a weak possible effect. The results showed that low-level microwave radiation did not cause statistically significant change in nerve pulse conduction velocity in human motor nerve fiber.

Letter to the Editor concerning Lai's letter on “Radial arm maze performance of rats following repeated low level microwave radiation exposure” [Bioelectromagnetics 25:49-57 (2004)

BioelectromagneticsVolume 26, Issue 7 p. 525-525 Letter to the Editor Letter to the Editor concerning Lai's letter on “Radial arm maze performance of rats following repeated low level microwave radiation exposure” [Bioelectromagnetics 25:49–57 (2004)]†‡ James R. Jauchem, Corresponding Author James R. Jauchem James.Jauchem@brooks.af.mil Air Force Research Laboratory, Brooks City-Base, TexasAir Force Research Laboratory, 8315 Hawks Road, Brooks City-Base, TX 78235.Search for more papers by this author James R. Jauchem, Corresponding Author James R. Jauchem James.Jauchem@brooks.af.mil Air Force Research Laboratory, Brooks City-Base, TexasAir Force Research Laboratory, 8315 Hawks Road, Brooks City-Base, TX 78235.Search for more papers by this author First published: 02 September 2005 https://doi.org/10.1002/bem.20163 † Dr. Cobb was offered the opportunity to respond to Dr. Lai's original Letter to the Editor, but for unavoidable reasons was not able to in a timely fashion. ‡ This article is a US government work, and, as such, is in the public domain of the United States of America. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume26, Issue7October 2005Pages 525-525 RelatedInformation

Letter to the Editor concerning “Radial arm maze performance of rats following repeated low-level microwave radiation exposure” by Cobb et al. [BEMS, 2004, 25:49-57] and “Letter to the Editor” by Lai [BEMS, 2005, 26:81

Letter to the Editor concerning “Radial arm maze performance of rats following repeated low-level microwave radiation exposure” by Cobb et al. [BEMS, 2004, 25:49-57] and “Letter to the Editor” by Lai [BEMS, 2005, 26:81

Interaction of low-level microwave radiation with nervous system – a quasi-thermal effect?

Interaction of low-level microwave radiation with nervous system – a quasi-thermal effect?