共查询到20条相似文献,搜索用时 31 毫秒
1.
In the recent years concerns whether exposure to electromagnetic fields (EMF) from base station antennae can cause adverse
health effects are grown. Great attention is paid on risk of EMF exposure to people living in a close proximity of base stations.
In this issue, a point of interest is the personnel mounting, adjusting and maintaining base stations. Their working tasks
require stay in high EMF levels’ conditions. There are only few studies concerning this specific occupational group. The results
from our previous investigation (Zaryabova and Israel 2006) show that in␣many cases on performing some specific tasks operators
are overexposed according to our national legislation, and ICNIRP guidelines. Here, we present an extended study covering
more base stations and more precise scenario for performed tasks and working positions. Results of exposure assessment are
presented. They include energetic load calculations on the basis of Bulgarian national legislation, and the corresponding
SAR values. Data are used to determine permissible time duration for each particular work operation and served as a base for
limiting the exposure and proposal for protective measures for the personnel. 相似文献
2.
In the recent years concerns whether exposure to electromagnetic fields (EMF) from base station antennae can cause adverse
health effects are grown. Great attention is paid on risk of EMF exposure to people living in a close proximity of base stations.
In this issue, a point of interest is the personnel mounting, adjusting and maintaining base stations. Their working tasks
require stay in high EMF levels’ conditions. There are only few studies concerning this specific occupational group. The results
from our previous investigation (COST 281—Graz, 2006) show that in many cases on performing some specific tasks operators
are overexposed according to our national legislation, and ICNIRP guidelines. Here, we present an extended study covering
more base stations and more precise scenario for performed tasks and working positions. Results of exposure assessment are
presented. They include energetic load calculations on the basis of Bulgarian national legislation, and the corresponding
SAR values. Data are used to determine permissible time duration for each particular work operation and served as a base for
limiting the exposure and proposal for protective measures for the personnel. 相似文献
3.
J. J. M. Cuppen G. F. Wiegertjes H. W. J. Lobee H. F. J. Savelkoul M. A. Elmusharaf A. C. Beynen H. N. A. Grooten W. Smink 《The Environmentalist》2007,27(4):577-583
A hypothesis is proposed how Low Frequency Electromagnetic Field (LF EMF) exposure can stimulate an immune response, based
on recent insights in immunology. We hypothesize that the Immunent EMF treatment induces mild stress to cells, which then
produce cytokines that function as alarms or so called danger signals for the immune system. In this way EMF treatment takes
the place of multiplying pathogens, and the damage these cause, in the triggering of an immune response. In a first series
of experiments in␣vitro common carp head kidney-derived phagocytes were used to determine ROS production as a measure for
immune activation. Exposure to LF EMF signals (200–5,000 Hz) at 5 μT or 1.5 mT led to 42 or 33% increase in immune activity,
respectively, compared to negative control values. EMF could also additionally stimulate chemically pre-stimulated samples
up to 18% (5 μT) or 22% (1.5 mT). Significance of increase in ROS production in the total series was: p < 0.0001. In a second series of experiments in␣vitro commercial goldfish were used. Groups of fish were housed under equal
conditions in at least four control tanks and 8–16 EMF-exposed tanks. Exposure was done with a predominantly vertical field
at field strengths (rms) between 0.15 and 50 μT. Without treatment mortality was about 50% after 18 days, while the treatment
at 5 μT reduced it to 20% on average. At field strengths 0.15, 0.5, 1.5, 5, 15 and 50 μT an equally strong effect was found.
Reducing the field strength to 0.05, 0.06, 0.01 and 0.003 μT showed a gradually decreasing effect, which only at 0.003 μT
is no longer statistically significant. Finally, in␣vitro experiments were done with 560 commercial broiler chickens exposed
to infection pressure from coccidiosis. EMF exposure at 6.5 μT reduced intestinal lesions by 40% and improved feed conversion
by 8%. 相似文献
4.
Chiyoji Ohkubo Hideyuki Okano Akira Ushiyama Hiroshi Masuda 《The Environmentalist》2007,27(4):395-402
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
5.
Gayane Ayrapetyan Anahit Grigoryan Erna Dadasyan Sinerik Ayrapetyan 《The Environmentalist》2007,27(4):483-488
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
6.
Lyubina Vesselinova 《The Environmentalist》2012,32(2):249-255
The importance of the assessment of the electromagnetic fields /EMF/ background as a health risk factor for the physiotherapy
personnel is discussed in this paper. Wide frequency and amplitude ranges as well as large variety of design prescribed in
the rehabilitation program form complicated work conditions. In this paper, we attempt to present and classify this specific
work environment, i.e., low intensive EMF background with non homogenous frequency and modulation characteristics, stochastic
changes running during day, ground or even underground units’ placement and professional specifics, i.e., chronic EMF expositions,
personnel’s trunk and hands exposure, dose-measurement absence, lack of program for prevention and prophylaxis for the assessment
of the relatively insufficiently elucidated potential of EMF as a harmful factor for medical staff. Our “Study of the biological
effects of the EMF among medical staff from PRM wards—potential of risk reduction”/initialized in 1999/and the original survey
card structure are presented in general here first. It has been shown the importance to extend the “native” studies among
homogenous professional groups, two of them presented there, as well as the study of the biological effects of EMF in their
different aspects, especially taking into account the elevated levels of ionizing and non-ionizing radiation in the environment.
This includes the special attention on the exposure of medical staff from PRM units and creation of adequate methods for prevention
of unnecessary exposure to these physical factors. 相似文献
7.
This paper discusses mutual interactions phenomena especially in the case of Transverse ElectroMagnetic (TEM) cell applications
as an exposure system in technical and biomedical studies. In many publications is described problem of influence of an object
upon the electromagnetic field (EMF) distribution inside a exposure system while inverse effect—influence of exposure system
on tested object is overlooked. The problem plays primary role if a correlation between investigations carried out in an enclosure
(e.g. TEM cell) and that in the free space is looked for. 相似文献
8.
The new recommendations of WHO and EC for legislation in Europe and other countries concerning non-ionizing radiation (NIR)
health and safety include exposure limits that are very debatable. ICNIRP Guidelines propose exposure limits for electromagnetic
fields in the frequency range up to 300 GHz based on short-term exposures and on thermal effects. The new EC proposal for
optical and laser safety legislation includes classification of sources of radiation—both lasers and other optical sources,
but not requirements for the methodology of classification. On the other hand, many new requirements have been set by the
WHO publication “Model Legislation for EMF Protection” concerning the responsibilities in the field of EMF health and safety.
Many specialists in the field of developing exposure limits have positions very far away from the proposed of the ICNIRP Guidelines
philosophy. The results are different approaches in developing standards and exposure limits, and differences more than 100
times in maximal permissible levels. We, the Bulgarian Program Committee on NIR, try to organize working groups and discuss
different philosophy for developing exposure limits for more than 10 years. This paper exposes our position in this area. 相似文献
9.
High frequency electromagnetic fields (EMF) are widely used for transmitting of radio and TV signals, in wireless communications,
etc. A huge number of people are exposed so the possible risk to human health from telecommunication technologies could be
significant even if biological effects are slight. The study of the biological effects of RF EM radiation could contribute
to better understanding of the possible health hazards. The levels of released hemoglobin serve as an indicator of hemolysis,
caused by increased membrane fragility. This study was designed to investigate the alterations in hemoglobin release after
in vitro exposure of human erythrocytes to GSM900 electromagnetic field. Erythrocyte suspensions with two different cell concentrations
(hematocrit 20% and 40%) were exposed to EM radiation from GSM mobile phone (carrier frequency 902 MHz, 2 W output power in
pulse) for 20 min in two different positions in relation to telephone antenna: Position 1 is in the centre of the major lobe
of the azimuth antenna pattern and Position 2 is between major and back lobes. Alterations in hemolysis were registered 0,
10, 20, 30, 40, 50 and 60 min after the treatment. Hemolysis was determined by measuring the absorbance of hemoglobin at 413 nm
in the supernatant obtained by centrifuging the suspensions. Hemolysis was expressed as hemoglobin concentration. Our data
indicated decrease in the hemoglobin level in irradiated suspensions. The GSM900 EMF exposure probably stabilized erythrocyte
membrane and caused reduction in the hemolysis depending on the EMF parameters, on the suspension water content (hematocrit)
and on the time elapsed after irradiation. 相似文献
10.
Electromagnetic field sources used for communication always have been subject of serious interest. There are many publications
concerning exposure and risk assessment of the working in such environment. Results of epidemiological study performed in
Bulgaria in the 1990's show exceeding of the maximal permissible values especially in radio stations for the personnel in
24 h working shift [Israel et al. (1992). Study of the electromagnetic in its influence on personnel working in radio and
TV stations, Report, National Centre of Hygiene, Medical Ecology and Nutrition; Israel and Tomov (2001). Epidemiological study
of the effects of radiofrequency radiation on operators in radio, TV and relay stations, Proceeding of the Eastern European
Regional Meeting and Workshop “Measurements and Criteria for Standard Harmonization in the field of EMF Exposure” and WHO
EMF Standards Harmonization Meeting, Varna, Bulgaria, 28 April—3 May, 2001, pp.145–153]. In the last years the situation is
strongly influenced by the development of the technology which leads to changes in equipment in radio and TV stations, using
lower power, facilitate the working regime. The paper presents data of exposure assessment of different professional groups
in selected radio and TV stations. Assessment is being performed on basis of EMF parameters values and energetic load calculations
according to the national legislation. Data are compared with the results of previous investigation to evaluate the new situation
in this branch. Exposure levels are much lower than those in the previous study, and lower compared to the exposure limits,
as well [Israel et al. (1992). Study of the electromagnetic in its influence on personnel working in radio and TV stations,
Report, National Centre of Hygiene, Medical Ecology and Nutrition; Israel and Tomov (2001). Epidemiological study of the effects
of radiofrequency radiation on operators in radio, TV and relay stations, Proceeding of the Eastern European Regional Meeting
and␣Workshop “Measurements and Criteria for Standard Harmonization in the field of EMF Exposure” and WHO EMF Standards Harmonization
Meeting, Varna, Bulgaria, 28 April—3 May, 2001, pp.145–153]. 相似文献
11.
Summary In an effort to explain the benefit of therapeutic use of electromagnetic fields (EMF) a systemic effect has been proposed
by us. To assess the efficacy of this approach, an objective biochemical approach was developed. Ten patients with Reflex
Sympathetic Dystrophy (RSD) were clinically evaluated, and lymphocytes were isolated from their blood samples obtained before
and after exposure of the uninvolved limb to an EMF. Utilizing a SpectraCell method that includes radio labeled molecules
and protein-free media for culturing the lymphocytes, an elevation of the content of fructose, serine, glycine, and calcium
cellular metabolic uptake were found following in the culture to EMF in comparison with non-exposed lymphocytes (p < 0.01). In addition, the pain level was determined by a conventional visual analogue scale (VAS) before and after EMF exposure,
evidencing a significant pain relief. Specifically, after exposure to 120 pps semi sinewave, 1500Gauss EMF, generated by a
THERAMAG∘ledR device, an improvement in the flexibility of the limb and a reduction in swelling of the affected extremity were detected
clinically. These findings are in concert with the new hypothesis that, with relief of pain, lymphocytes are predominately
altered in their cell cycle from M phase to S phases associated with increased structuring of intracellular water. A consideration
of the basic understanding of the role lymphocytes may be inferred from this preliminary study. An extensive review of the
literature on the basic science and therapeutic use of magnetic fields in humans is provided in an attempt to understand the
relevance of magnetic therapy of specific pain syndromes. 相似文献
12.
Marko S. Markov 《The Environmentalist》2007,27(4):465-475
Magnetic and electromagnetic fields are now recognized by the 21st century medicine as real physical entities that promise
the healing of various health problems, even when conventional medicine has failed. Today magnetotherapy provides a non-invasive,
safe, and easy method to directly treat the site of injury, the source of pain and inflammation, and other types of diseases
and pathologies. Millions of people worldwide have received help in treatment of musculoskeletal system, as well as pain relief.
Pulsed electromagnetic fields are one important modality in magnetotherapy and recent technological innovations, such as Curatron
pulsed electromagnetic field devices, offer excellent, state of the art computer controlled therapy system. In this article
the development, state of the art and future of pulsed electromagnetic field therapy are discussed. 相似文献
13.
This paper describes tools developed through a community consultative process to help decision makers manage electrical and magnetic fields (EMF) health risk. The process involved in‐depth interviews with experts (N=12) and focus group discussions with seven different stakeholder groups. The results reveal commonly held intense public concerns about the long‐term health effects of EMF. These concerns were further reinforced by the lack of public trust in both government and industry with regards to EMF risk management. Overall, the participants wanted tools that can be used to manage EMF information, scientific uncertainty about EMF and the complex environment in which EMF issues are embedded. The findings contributed to a mapping out of response formats to address public concerns related to risk, hazard, trust, accountability and fairness across a range of stakeholder groups. These tools and their roles in the management of complex and variable risks, involving new circumstances (e.g. privatization) and information (e.g. new scientific studies) are presented. The importance of recognizing and working with uncertainty through adaptive management strategies, using qualitative approaches, is also discussed. 相似文献
14.
Yury Grigoriev 《The Environmentalist》2012,32(2):193-200
Today world population lives in a new electromagnetic environment, characterized with (i) around the clock enforcement of
chronic exposure of all age and gender groups to a wide range of modulated electromagnetic fields (EMF) from base stations;
(ii) daily, repeated from early childhood throughout entire life exposure to EMF RF mobile phone the brain and vestibular
receptor apparatus and auditory analyzers, located directly “under the EMF beam” in the inner ear. On the other hand, the
world science and epidemiology is missing well-planned and executed research results of prolonged exposure of EMF RF on the
brain. International recommendations and domestic guidelines do not include changing conditions of RF EMF on the population:
the brain has become a critical organ, and the children entered the risk group. The population continues to actively use the
mobile phone. In this situation the problem of assessing the risk of mobile communications has become a social and ethical. 相似文献
15.
To better understand the affect of different levels of EMF on one’s brain activity, the Hodgkin–Huxley model has been used
to describe the generation of an active potential in the nerve cell membrane. The theoretical calculations have shown that
by the simultaneous affect of both passing an electrical potential and external very low frequency AC, one’s excitation pulses
may be suppressed beginning with a certain level of external current. The level of this current depends on the frequency.
It is postulated that to eliminate this suppression, the brain increases its normal level relatively to the lower limit. It
is also postulated that the brain “tunes up” in the presence of external AC, by increasing the amplitude of its own excitation
signals so that suppression does not occur. It is possible that this “tuning” process lasts some time after removing the external
EMF as the brain adapts. This has been observed experimentally. 相似文献
16.
Andreas Neocleous 《The Environmentalist》2005,25(2-4):247-250
Summary This paper deals with the evaluation of Extremely Low Frequency (ELF) Electromagnetic Fields (EMF) produced by high tension
wires on pylons and substations, which were preliminarily investigated by taking measurements in schools (on behalf of the
Environmental Committee of Limassol). It publicizes the level of EMF from the above sources and makes an attempt to compare
them with various exposure limits.
Finally, certain measures to be taken by the responsible authorities are suggested, as possible actions aiming at the protection
of the Cypriot people from any EMF health risk. 相似文献
17.
Electromagnetic field (EMF) measurements, for labor safety and environment protection purposes, are performed in the near-field.
Inaccuracy of the far-field EMF measurements oscillates around ±1 dB or bit worse; in the near-field measurements, errors
at the level of ±6 dB must be sometimes accepted. In the case of non-stationary EMF measurements, their sense may be changed
from quantitative to qualitative ones. In order to make it possible an estimation of the non-stationary EMF measurement accuracy,
it is proposed new method of the meters calibration. The method is based upon a standard excitation with identical signal
as the measured one. A set for the purpose includes a pulse generator (of frequency and pulse rating identical with the radiation
source) and computer-controlled amplitude modulator that reflects the radiation pattern of an antenna (e.g. radar one) and
its rotations. Contrary to calibration using monochromatic continuous wave (CW) excitation, proposed method should be repeated
for any radiation source. The disadvantage is compensated by a possibility to estimate (additional) error of the method. Calculations
show it at the level of 10%. 相似文献
18.
Hamdy Ellaithy 《The Environmentalist》2005,25(2-4):251-255
Summary This work addresses one of the crucial problems regarding the confusion between the existence of any actual health hazard
as documented and the public perception of this hazard. The wide spread use of Radio Frequency (RF) fields in general and
in mobile communication in particular has warranted a careful assessment of the public response especially in developing nations.
This study comes in response to the growing penetration rate of about 10% of mobile phones in Egypt, which almost exceeds
the current rate of fixed lines. It is based on a survey conducted in 2003 and includes different age groups, different levels
of education, sex and standard of living.
The proposed work discusses the misconceptions and health concerns of the public as far as the spread of mobile communication
is concerned and compare it with similar surveys in different countries and calibrate the results with established scientific
facts. 相似文献
19.
František Vožeh Antonín Doněk Jan Cendelín Ivana Korelusová Jan Vrba 《The Environmentalist》2007,27(4):501-504
The effect of long-term exposure to high frequency electromagnetic field (HF EMF) on some somatic and neural characteristics
was studied in neurodefective Lurcher mutant (+/Lc) and normal wild type mice (+/+). Both newborn and young adult (3 months)
animals derived from two strains (C3H, B6CBA) were exposed to HF EMF (870 MHz) from 1st to 21st day or from 91st to 120th
day respectively. In animals of both groups and controls we observed the development of body weight. Moreover, in the HF EMF
exposed adult B6CBA animals we studied spatial learning ability, motor functions and the CNS excitability. To investigate
specific energy absorption rate (SAR) in experimental animals we have done the basic 3D calculations of the electromagnetic
energy distribution in the simplified model of the mouse. The HF EMF exposed animals exhibited mild differences of body weight
between them and unexposed controls. The long-term exposure to HF EMF did not significantly influence the ability to learn
in the Morris water maze. However, significant lower swimming speed was found in the irradiated +/Lc as well as lower motor
activity of +/+ in the open field when compared to controls. No significant differences were found between HF EMF irradiated
animals and controls in examination of the CNS excitability and motor functions. 相似文献
20.
Electromagnetic fields exposure assessment methodology is briefly presented. The basic problems defined for the practical
use of electromagnetic fields measurements and numerical calculations carried out for workers exposure assessment in real
occupational situations are discussed. The examples of data from real workplace are presented, focusing: spatial distribution
of electromagnetic fields affecting worker’s body, complex characteristics of the frequency content, workers activities/moving
in the workplace, field impedance, etc. The situation when the use of calculations is required is discussed. The basic requirements
for workers exposure assessment protocols are presented. The possible range of the use of internal and external measures of
exposure level is also discussed. 相似文献