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1.
We have earlier shown that radio frequency electromagnetic fields can cause significant leakage of albumin through the blood–brain barrier of exposed rats as compared to non-exposed rats, and also significant neuronal damage in rat brains several weeks after a 2 h exposure to a mobile phone, at 915 MHz with a global system for mobile communications (GSM) frequency modulation, at whole-body specific absorption rate values (SAR) of 200, 20, 2, and 0.2 mW/kg. We have now studied whether 6 h of exposure to the radiation from a GSM mobile test phone at 1,800 MHz (at a whole-body SAR-value of 13 mW/kg, corresponding to a brain SAR-value of 30 mW/kg) has an effect upon the gene expression pattern in rat brain cortex and hippocampus—areas where we have observed albumin leakage from capillaries into neurons and neuronal damage. Microarray analysis of 31,099 rat genes, including splicing variants, was performed in cortex and hippocampus of 8 Fischer 344 rats, 4 animals exposed to global system for mobile communications electromagnetic fields for 6 h in an anechoic chamber, one rat at a time, and 4 controls kept as long in the same anechoic chamber without exposure, also in this case one rat at a time. Gene ontology analysis (using the gene ontology categories biological processes, molecular functions, and cell components) of the differentially expressed genes of the exposed animals versus the control group revealed the following highly significant altered gene categories in both cortex and hippocampus: extracellular region, signal transducer activity, intrinsic to membrane, and integral to membrane. The fact that most of these categories are connected with membrane functions may have a relation to our earlier observation of albumin transport through brain capillaries.  相似文献   

2.
In spite of growing concern about the influence of magnetic fields on biological systems, the interaction between extremely low frequency magnetic field (ELF magnetic fields) and biological structures at the cellular level remains obscure. The aim of this study was to investigate if 50 Hz magnetic fields could have an effect on the neuronal excitability and firing responses. Under Current-Clamp condition, exposure to 50 Hz ELF magnetic fields at 2 mT or 0.8 mT intensities resulted in an increase in the peak amplitude of action potential and after hyperpolaization potential in a time dependent manner. Both magnetic field intensities decreased also the firing frequency and the duration of action potential. Taken together, these data suggest that 50 Hz ELF magnetic fields at 2 mT or 0.8 mT intensities may change the electrophysiological behavior of neuronal cells and underlying ion channel currents.  相似文献   

3.
The environment in which biology exists has dramatically changed during the last decades. Life was formed during billions of years, exposed to, and shaped by the original physical forces such as gravitation, cosmic irradiation and the terrestrial magnetism. The existing organisms are created to function in harmony with these forces. However, in the late 19th century mankind introduced the use of electricity and during the very last decades, microwaves of the modern communication society spread around the world. Today one third of the world’s population is owner of the microwave-producing mobile phones. The question is: to what extent are living organisms affected by these ubiquitous radio frequency fields? Since 1988 our group has studied the effects upon the mammalian blood-brain barrier (BBB) by non-thermal radio frequency electromagnetic fields (RF-EMF). These have been revealed to cause significantly increased leakage of albumin through the BBB of exposed rats as compared to non-exposed animals—in a total series of about two thousand animals. One remarkable observation is the fact that the lowest energy levels give rise to the most pronounced albumin leakage. If mobile communication, even at extremely low energy levels, causes the users’ own albumin to leak out through the BBB, also other unwanted and toxic molecules in the blood, may leak into the brain tissue and concentrate in and damage the neurons and glial cells of the brain. In later studies we have shown that a 2-h exposure to GSM 915 MHz at non-thermal levels, gives rise to significant neuronal damage, seen 28 and 50 days after the exposure. In our continued research, the non-thermal effects (histology, memory functions) of long-term exposure for 13 months are studied as well as the effects of short term GSM 1,800 MHz upon gene expression. Most of our findings support that living organisms are affected by the non-thermal radio frequency fields. Studies from other laboratories in some cases find effects, while in other cases effects are not seen. Our conclusion is that all researchers involved in this field have the obligation to intensify this research in order to reduce, or avoid, the possible negative effects of the man made microwaves!  相似文献   

4.
In our paper we studied the effects of exposure to ELF (extremely low frequency) or musically generated TAMMEF (therapeutic application of musically modulated electromagnetic fields) electromagnetic fields on the tumor necrosis factor alpha (TNF-α) release induced by a lipopolysaccharide (LPS) from cultured human lymphomonocytes of peripheral blood. Lymphomonocytes, isolated from blood donors buffy-coat, were prepared using standard techniques in cell culture flasks, kept in CO2 incubator, with controlled temperature and humidity for 5 days. Flasks were subjected to an ELF electromagnetic field (100 Hz sinusoidal) or to TAMMEF electromagnetic fields (with intensity, frequency, and wave shape randomly modified in time, so that all possible codes can occur during a single application). The TNF-α release was determined by ELISA test every 24 h for 92 h and the results were evaluated by a non-parametric test. LPS induces a stronger TNF-α release in cultures that were subjected to ELF when compared with cultures subjected to TAMMEF, at each time period of the experimental protocol. These results seem to indicate that TAMMEF is able to induce a complex modulation of LPS-induced TNF-α release, a cytokine with pro inflammatory property whose release during chronic or neoplastic inflammatory diseases has strong negative effects on several organ systems.  相似文献   

5.
Summary Since IARC classified ELF magnetic field as Possibly Carcinogenic to Human the fear from 50/60 Hz magnetic field exposure had been increased to the state of public “panic”. Subsequently, environment quality preservation organizations increased their pressure on their government to adopt the “precautionary principle” and to reduce the allowable ELF Magnetic Field exposure to much lower values than are recommended by ICNIRP-1998. As an example the present Environmental Ministry in Israel recommendation is to lower the ELF Field exposure to 10 mG averaged over 24 h. As a result of this stringent exposure guideline imposed by the government, electrical engineers who are involved in the deployment and installation of large and medium electrical utilities, such as overhead power lines, transformers, UPS systems, electrical public transportation, switching stations, etc., are much more aware to the need to employ special measures and methods for reducing the magnetic fields that might be emitted from such utilities. There are few computer codes that are capable of analyzing with great accuracy magnetic and electric fields surrounding single phase and three phase electrical utilities in a 3-D system. The best presentations of the analysis results are by equi-value contours depicting electric and magnetic fields. This graphical presentation is a powerful design tool that enables better deployment and installation design aided to reduce the magnetic field emissions from high-power electrical utilities. This paper describes the various types of graphical presentations available for ELF field contours, the dependent and independent variants and parameters, magnetic field animation for optimization of power line installation and routing, and finally an example that demonstrates the usefulness of the graphical presentation tools.  相似文献   

6.
The utility and the safety of the extremely low frequencies (ELF) electromagnetic fields in the treatment of numerous diseases have been demonstrated. Moreover, the effects of these fields seem to depend on their respective codes (frequency, intensity, waveform). We want to value the effects and the safety of the therapeutic application of a musically modulated electromagnetic field (TAMMEF) system, which field is piloted by a musical signal and its parameters (frequency, intensity, waveform) are modified in time, randomly varying within the respective ranges, so that all possible codes can occur during a single application. Sixty subjects, affected by shoulder periarthritis were enrolled in the study and randomly divided into three groups of 20 patients each: the first exposed to TAMMEF, the second exposed to ELF, the third exposed to a simulated field. All subjects underwent a cycle of 15 daily sessions of 30 min each and a clinical examination upon enrolment, after 7 days of therapy, at the end of the cycle and at a follow-up 30 days later. All the patients of TAMMEF group and ELF group completed the therapy without the appearance of side effects: they presented a significant improvement of the subjective pain and the functional limitation, which remained stable at the follow-up examination. In those exposed to a simulated field group, there was no improvement of the pain symptoms or articular functionality. This study suggests that the TAMMEF system is efficacious and safe in the control of pain symptoms and in the reduction of functional limitation in patients with shoulder periarthritis. Moreover, the effects of the TAMMEF system cover those produced by the ELF field.  相似文献   

7.
The effects of 4 Hz extremely low frequency Electromagnetic Fields (ELF EMF), Infrasound (IS) and hydrogen peroxide (H2O2) on Na+–K+ pump-induced transient inhibition of heart muscle contractility was studied. It was documented that EMF-treated and H2O2-containing physiological solution had synergic depressing effect on Na+–K+ pump-induced inhibition of muscle contractility, while the IS had elevation effect on it. On the basis of the obtained data the H2O2 could be suggested as the messenger through which the stimulation effect of EMF on heart muscle is realised, while the relaxing effect of IS on heart contractility is due to the decrease of CO2 solubility of muscle bathing aqueous medium.  相似文献   

8.
The effects of extremely low-frequency electromagnetic field (ELF EMF) and ELF-modulated millimeter waves (MMW) on physicochemical properties of physiological solution (PS) at different environmental medium were studied. The existence of frequency “windows” at 4 Hz and 8 Hz frequencies of ELF EMF and ELF-modulated MMW which have different effects on heat fusion period (HFP), hydrogen peroxide (H2O2) formation and oxygen (O2) content of water solution and different dependency on temperature, background radiation (BGR) and illumination was shown. The obtained data allow us to suggest that cell bathing medium serving as a target through which the biological effects of ELF EMF and ELF-modulated MMW on cells are realized is extra sensitive to environmental factors. Therefore, the variability of experimental data on EMF biological effects, obtained in different laboratories can be explained by different environmental conditions of experiments, which very often are not considered adequately.  相似文献   

9.
Concerns on health effects of radiofrequency (RF) signals have been discussed. Particularly, the effect on the central nerve system is one of main interest among the general public. So far, there are lots of studies regarding the RF effect on the Blood Brain Barrier (BBB), but no study of the RF effect on the Blood Cerebrospinal fluid Barrier (BCB). In this study we explored the effect on BCB function by radiofrequency electromagnetic fields (RF-EMF) exposure. To attain this purpose, we set about to make a real-time measuring system for BCB function using a micro-perfusion method and examined the short time exposure experiment using rats. Our data suggested the 30 min single exposure of 1.5 GHz RF-EMF at the brain average SARs of 9.5 W/kg for adult and 10.4 W/kg for juvenile, did not affect BCB function in rats under the experimental conditions.  相似文献   

10.
Osteoarthritis (OA) is a chronic degenerative condition involving the joints caused by metabolic changes in chondrocytes metabolism. Treatment with magnetic fields (EMFs) produces benefits to patients affected by this pathology. The present research has the aim to investigate, by a proteomic approach, the effect of magnetic fields on cultured chondrocytes, because EMFs interferes greatly with OA chondrocytes metabolism. Human osteoarthritic chondrocytes were obtained from the femur head of osteoarthritis adult patients and were cultured under standard conditions and exposed for precise times both to extremely low-frequency (ELF; 100-Hz) electromagnetic fields and to the Therapeutic Application of Musically Modulated Electromagnetic Fields (TAMMEF), which are characterized by variable frequencies, intensities, and wave shapes. We tested the effects of the different exposure by 2-DE analysis and demonstrated that chondrocytes metabolism was highly influenced by the treatment with EMFs; in fact many proteins change their expression after the stimulation, but differently, depending on whether we use ELF or TAMMEF system.  相似文献   

11.
Although most of jet fuels are currently made from petroleum, nonfood oilseeds such as flax and canola seeds may be an alternative for renewable jet fuel production in the near future. Vegetable oils produced from those oilseeds can be upgraded to liquid hydrocarbons to produce renewable jet fuels. The production efficiency and cost are heavily relied on the vegetable oil fatty acid profile (FAP). Previous research indicated that vegetable oil FAP is affected by oilseed species and oil extraction conditions. Cold press oil extractions from flax and canola seeds were conducted. The effect of the frequency controlling the screw rotating speed on the oil extraction efficiency and quality was discussed. Characterization of the vegetable oils produced, including density, pH value, viscosity, moisture, element component, heating value and FAP, was carried out. The residual oil contents left in the cold press meals were also determined. The results show that the oil extraction efficiency of oilseeds increased when the frequency decreased. For flax and canola seeds, their highest oil extraction efficiency was the same (81.0%), which was both obtained at 15 Hz. The cold press frequency had a minor influence on the FAPs of flax oils. However, the FAPs of canola oils produced at 15 Hz were different from those produced at 20 Hz and 25 Hz to some extent. The main fatty acid in flax and canola oils was linolenic acid and erucic acid, respectively.  相似文献   

12.
Abstract

The modification effect of Nafion on the generation performance at different temperatures and methanol concentrations was investigated. The direct methanol fuel cell performances and electrochemical properties of the DMFC system using as-received Nafion117, a modified Nafion membrane, and using the Nafion117 MEA preparation by spray treatment on the surface of each catalyst layer for conductivity improvement. The open circuit voltage using the modified Nafion membrane was higher than that using Nafion117 at the cell temperature of 343–383 K and methanol concentration of 1.5–10 kmol/m3. The spray treatment of MEA was effective and improved the short circuit current up to 461 mA/cm2 at a 5 kmol/m3 methanol concentration in comparison with no treatment of MEA because of the low interfacial resistance. The power density of 75 mW/cm2 (no treatment Nafion117 MEA:40 mW/cm2) was obtained. The method of the spray treatment was found to be very effective for the DMFC system. The cell performance of Nafion117 MEA increased with the methanol concentration because of the reduction of the concentration overvoltage.  相似文献   

13.
This paper estimates the environmental impacts and damage costs (‘external costs’) of synthetic nitrogen fertilizer and discusses options for reducing these impacts, including their consequences for farmers and for producers of fertilizer. The damage costs of the fertilizer life cycle that could be estimated are large, about 0.3 [euro]/kgN (compared to the current market price of about 0.5 [euro]/kgN); much of that is due to global warming by N2O and CO2 emissions during fertilizer production and N2O emissions from fertilized fields. Policy options for internalizing these costs are discussed, and the consequences of reduced fertilizer input on crop yield are explored. If the damage costs were internalized by a pollution tax or tradable permits that are auctioned by the government, the economic consequences would be heavy, with a large revenue loss for farmers. However, if it is internalized by tradable permits that are given out free, the revenue loss for farmers is small. The loss for fertilizer producers increases linearly with the amount of external cost that is internalized, by contrast to the loss for farmers which increases quadratically but is very small for a damage cost of 0.3 [euro]/kgN. Expressed as a change in the fertilizer-dependent part of the farmers' revenue (crop yield × crop price – fertilizer used× fertilizer price), the decrease is less than 0.5% for most crops; the losses are larger only for crops with low [euro]/ha revenue. Averaged over wheat, barley, potatoes, sugar beet and rapeseed, the loss to farmers is about 0.1% in the UK and 0.4% in Sweden. The revenue loss for fertilizer producers is larger, about 8% in the UK and 14% in Sweden.  相似文献   

14.
The possible mechanisms of interactions of electromagnetic fields (EMF) with biological systems are often discussed in bioelectromagnetics in light of thermal versus nonthermal mechanisms. This paper attempts to show the principle difference between the biophysical and engineering approaches to biological mechanisms of EMF initiated bioeffects. While biophysical approach is based on experimentally obtained data on biological responses to the applied EMF, the engineering approach strongly relies on specific absorption rate (SAR) value. With experimental data, comparing effects of low- and high-frequency electromagnetic fields, discussing modulation of radiofrequency (RF) signals, the author demonstrates the superiority of the nonthermal approach. Biological windows, resonance mechanism, and various reported biological effects of geomagnetic fields are also in favor of the nonthermal mechanisms. Finally, one potential nonthermal mechanism involving the role of calmodulin in cellular functions is shown in this paper.  相似文献   

15.
Numerous studies have demonstrated the utility of extremely low frequencies (ELF) electromagnetic fields in the treatment of pain. Moreover, the effects of these fields seems to depend on their respective codes. In our study we want to value the effects and the safety of the TAMMEF (Therapeutic Application of a Musically Modulated Electromagnetic Field) system, which field is piloted by a musical signal and its parameters are modified in time, randomly varying within the respective ranges, so that all possible codes can occur during a single application. Ninety subjects, affected by chronic low back pain, were enrolled in the study and randomly divided into three groups of 30 patients each: A exposed to TAMMEF, B exposed to ELF, C exposed to a simulated field. All subjects underwent a cycle of 15 daily sessions of 30 minutes each and a clinical examination upon enrolment, after 7 days of therapy, at the end of the cycle and at a follow-up 30 days later. All the patients of groups A and B completed the therapy without the appearance of side effects: they presented a significant improvement of the subjective pain and the functional limitation, which remained stable at the follow-up examination. In group C, there was no improvement of the pain symptoms or articular functionality. This study suggests that the TAMMEF system is efficacious and safe in the treatment of patients with chronic low back pain.  相似文献   

16.
This study is aimed to investigation of the effect of modulated 450 MHz microwave radiation on the EEG inter-hemispheric asymmetry. Ten cycles of the microwave exposure (1 min off and 1 min on) at fixed modulation frequency were applied on two groups of healthy volunteers. The first group of 13 subjects was exposed to microwave radiation modulated at 14 Hz and the second group of 15 subjects at 40 Hz frequency. The peak specific absorption rate (SAR) average over 1 g was 0.303 W/kg. Differences in SAR between hemispheres were up to 20 dB. Rod antenna was located from the left side of the head. Differences of relative changes in EEG energy between symmetric channels FP1–FP2, T3–T4, P3–P4 and O1–O2 in exposed and sham conditions were analysed. The results showed increase in EEG energy from the left side caused by microwave exposure. Statistical analysis done for the whole group of subjects didn’t reveal significant differences in inter-hemispheres asymmetry between exposed and sham conditions. However, statistical analysis performed for individual subjects detected significant differences in asymmetry caused by exposure for 15–35% of individuals.  相似文献   

17.
Authors review the importance of studying the effects of electromagnetic fields (EMF) on microcirculatory system, especially in respect of possibility that vasculature may have direct and indirect role in interaction of static magnetic fields (SMF). We outline the physiological importance of microcirculation and relatively new methods of evaluation technique in vivo and explain in details the local and/or whole body exposure effects of SMF with␣range of 0.3–180 mT, power frequency EMF with range of 0.1–30 mT and microwaves at 1.5 GHz with range 0.08–8 W/kg brain average specific absorption rate (SAR) on microcirculatory systems in different tissues in experimental animals.  相似文献   

18.
The purpose of this work was to investigate the impact of user’s positions in close space over the variations of SAR distribution in human head induced from mobile phone under the worst case conditions. The “worst case” considered in this paper refers to conditions that include (1) a half-wavelength dipole antenna, placed near the model of human head—SAM phantom; (2) a vertically oriented dipole antenna, parallel to the side walls of closed space for maximum reflection; (3) metallic closed space acts as a resonant cavity; and (4) 360 randomly selected observation points. We also used a free space model for comparative purposes. The maximum 1- and 10-g average SAR and average SAR in whole-exposed object probability density function curves have been derived to illustrate the percentage of SAR values that have been induced inside SAM for different locations of user in the closed space. The obtained results show that in more than 86.7% of all investigated user’s positions in the metallic closed space, the induced maximum 1-g average SAR in user’s head is in the boundaries of ±10% of maximum 1-g average SAR, when the user use mobile phone in free space. This relationship keep still at maximum 10-g average SAR, where in 85.9% from all investigated user’s positions, SAR values are in boundaries of ±10% of maximum 10-g average SAR in free space. The results showed that closed space causes more significant changes on average SAR in whole-exposed object than maximal SAR values. When we estimated the average SAR in whole-exposed SAM in 85% from all investigated user’s position in closed space, the induced SAR is higher than SAR values in free space model. It can be noted that the highest obtained SAR values in closed space were with 8.5% (for 1 g), 6.7% (for 10-g average SAR), and 15.1% (for average SAR in whole SAM) higher than these of the free space.  相似文献   

19.
This study was aimed to investigate the changes in the human electroencephalographic (EEG) signal caused by modulated low-level microwaves. The 450 MHz microwave exposure modulated at 40 Hz and 70 Hz frequencies was applied to a group of 15 volunteers. The field power density at the scalp was 0.16 mW/cm2. Ten cycles of the exposure (1 min on and 1 min off) at both modulation frequencies were applied. Analysis of the EEG signal was performed using three different methods: nonlinear method of scaling analysis for length distribution of low variability periods (LDLVP), relative changes in EEG energy (S-parameter) and beta ratio (H-parameter). The analysis revealed significant changes caused by microwave for the whole group (H-parameter method). The exposure caused increase of the EEG beta power (S-parameter method). Statistically significant changes in EEG were detected for four subjects (26.7%) at 40 Hz modulation frequency (LDLVP method).  相似文献   

20.
Many moral philosophers have criticized intensive animal farming because it can be harmful to the environment, it causes pain and misery to a large number of animals, and furthermore eating meat and animal-based products can be unhealthful. The issue of industrially farmed animals has become one of the most pressing ethical questions of our time. On the one hand, utilitarians have argued that we should become vegetarians or vegans because the practices of raising animals for food are immoral since they minimize the overall happiness. Deontologists, on the other hand, have argued that the practices of raising animals for food are immoral because animals have certain rights and we have duties toward them. Some virtue ethicists remain unconvinced of deontic and consequentialist arguments against the exploitation of animals and suggest that a virtue-based approach is better equipped to show what is immoral about raising and using animals for food, and what is virtuous about ethical veganism.  相似文献   

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