Biological effects of low power microwaves: experimental evaluation at molecular and cellular levels

The Radiofrequency (RF) and Microwave (MW) radiation refer to electromagnetic fields with frequencies between 300 kHz -300 MHz and 300 MHz-300 GHz respectively. The most important applications of RF/MW found in various communication systems (mobile telephony), and microwave heating (food technology and medical applications). The RF/MW radiation is non-ionizing because the energy levels associated with it are not high enough to cause ionization of atoms and molecules. But RF/MW can produce resonance interactions with ions and with charged macromolecules, and such interactions can significantly alter biochemical functions. A large body of research has shown that MW/RF causes an increased production of free radicals and reactive oxidant species in living tissues, and that this increased oxidant stress can damage DNA. This damage can and does occur at power levels well below those levels that could produce damage by thermal mechanisms. The mobile phone system operating at about 900 and 1800 MHz for Global System for Mobile Communication (GSM); 800 and 900 MHz for Wideband Code Division Multiple Access (WCDMA); 1800 MHz for Long Term Evolution (LTE); and 2100 MHz for Universal Mobile Telecommunications System (UMTS) is located in a region of the spectrum that is referred to as both microwave (MW) radiation and RF radiation. There is a large body of internationally accepted scientific evidence which points to the existence of non-thermal effects of RF/MW radiation. The issue at the present time is not whether such evidence exists, but rather what weight to give it. RF/MW radiation research have shown that RF/MW transmissions of the type used in digital cellular antennas and phones can have critical effects on cell cultures, animals, and people in laboratories and have also found epidemiological evidence of health effects at "non-thermal levels," where the intensity of the RF/MW radiation was too low to cause heating. This PhD research project is aimed at investigating the effects of low intensity/power MW radiation on selected cells and proteins with the specific focus on the frequencies emitted by mobile phones. The project includes the following sub-studies: 1. Design and fabrication of the custom-made microwave exposure camera. 2. Modeling/simulation of the generated field inside the custom-made exposure camera. 3. Experimental evaluation of the effects of low level microwaves on selected biological systems

Effects of low power microwaves at 1.8, 2.1, and 2.3 GHz on l-Lactic dehydrogenase and glutathione peroxidase enzymes

Radiofrequency/microwave (RF/MW) radiation has been integrated in almost every aspect of today's modern life and applied in radar, telecommunication systems, health/medical devices, and food sterilization technology. However, the increasing rate of exposures to RF/MW radiation, especially exposures from mobile phones, has raised health concerns and stimulated much research into biological and health effects of low power MWs. The heating effect of the MWs is already well known and documented; however, a doubt remains on the existence of non-thermal biological effects. This study evaluates the effects of low power MWs on kinetics of l-Lactic dehydrogenase and Glutathione peroxidase enzymes irradiated at the frequencies of 1.8, 2.1, and 2.3 GHz and power of 10dBm using the commercial Transverse Electro-Magnetic cell. The selected frequencies are used frequently in G4 and G5 mobile networks. The findings reveal that MWs at the studied parameters induce changes in the enzymes' kinetics, which lead to modulation of rate of change in corresponding reactions these enzymes catalyze

Effects of non-thermal microwave exposures on the proliferation rate of saccharomyces cerevisiae yeast

This study evaluates the effect of non-thermal weak radiofrequency microwave (RF/MW) radiation on the proliferation response of the yeast Saccharomyces cerevisiae. S. cerevisiae strains type II (Sigma) were exposed to the microwaves at 900MHz and the selected powers of 13dBm, 3dBm and -7dBm using the Transverse Electro-Magnetic (TEM) cell. The average specific absorption rate (SAR) for a single cell was 0.12 W/kg. SAR was calculated by averaging the individual parameters of the cell components in accordance with their volume fraction in live cells

Effects of low power microwave radiation on biological activity of L-Lactate dehydrogenase enzyme and growth rate of S. Cerevisiae yeast

Recently, microwave radiation, a type/subset of non-ionizing electromagnetic radiation (EMR) has been widely used in industry, medicine, as well as food technology and mobile communication. Use of mobile phones is rapidly growing. Four years from now, 5.1 billion people will be mobile phone users around the globe - almost 1 billion more mobile users than the 4.3 billion people worldwide using them now. Consequently, exposure to weak radiofrequency/microwave radiation generated by these devices is markedly increasing. Accordingly, public concern about potential hazards on human health is mounting [1]. Thermal effects of radiofrequency/microwave radiation are very well-known and extensively studied. Of particular interest are non-thermal effects of microwave exposures on biological systems. Nonthermal effects are described as changes in cellular metabolism caused by both resonance absorption and induced EMR and are often accompanied by a specific biological response. Non-thermal biological effects are measurable changes in biological systems that may or may not be associated with adverse health effects. In this study we studied non-thermal effects of low power microwave exposures on kinetics of Collagenase enzyme and growth rate of yeast Saccharomyces Cerevisiae strains type II. The selected model systems were continuously exposed to microwave radiation at the frequency of 968MHz and power of 10dBm using the designed and constructed (custom made) Transverse Electro- Magnetic (TEM) cell [2]. The findings reveal that microwave radiation at 968MHz and power of 10dBm inhibits Collagenase enzyme activity by 26% and increases significantly (15%) the proliferation rate of yeast cells

The effects of low power microwaves at 500 MHz and 900 MHz on yeast cells growth

In the last few decades, the use of microwave radiation has greatly increased in radar and communication systems, food-processing technology and medical ¯eld. Development of consumer and medical microwave devices for clinical diagnosis and therapy has also prompted widespread interest and stimulated much research into the mechanisms of interaction between microwave radiation and living matter. Two types of e®ects can be ascribed to microwaves, i.e., thermal and non-thermal. Non-thermal biological e®ects are measurable changes in biological systems that may or may not be associated with adverse health e®ects. It was shown that low power microwaves can a®ect enzymes activities. Little is known about the molecular mechanisms involved in putative non-thermal e®ects. One hypothesis is that low power microwave radiation can induce dipole oscillations in a protein's active site and thus, can alter its function. This study evaluates the e®ect of low power microwave radiation on the proliferation rate of yeast Saccharomyces cerevisiae strains type II, which were exposed to the microwaves at the frequencies of 500MHz and 900MHz and the selected powers of 0 dBm, 10 dBm, ¡10 dBm, 13 dBm, ¡13 dBm, 17dBm and ¡17dBm using the Transverse Electro-Magnetic (TEM) cell. The average speci¯c absorption rate (SAR) for a single cell was 0.12 W/kg. SAR was calculated by averaging the individual parameters of the cell components in accordance with their volume fraction in live cells. A comparative analysis of changes in the proliferation rate of the irradiated vs. non- radiated yeast cells was performed for the selected frequencies and powers, with the results being presented and discussed

Delayed diagnosis in the maxillofacial region: Two case reports

While conventional CT scan has historically been used for maxillofacial bone imaging. The introduction of cone beam CT (CBCT) in the new millennium has revolutionized the use of CT for dental and maxillofacial diagnoses. This paper presents two clinical examples of delayed diagnoses associated with maxillofacial imaging, describes the reasons for the delays and offers potential preventive measures. The first case involves a delay in the diagnosis of non-Hodgkin's lymphoma in a 49-year-old female who was being treated for an odontogenic problem. In the second case, a 9-year-old female who presented with a limited ability to open her mouth was mistakenly diagnosed with muscles spasm. Subsequently, she was found to have an elongation of the right lateral pterygoid plate that interfered with her right mandibular body, which restricted the degree to which she could open her mouth. A thorough clinical examination and accurate radiographic interpretation combined with a complete medical history can minimize these types of diagnostic delays. If the dentist is unable to conclusively reach a diagnosis, the patient should be referred immediately to a specialist who can better manage the specific medical problem. Keywords: Diagnosis, Maxillofacial, Non-Hodgkin's lymphoma, TM