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1.
The aim of this paper is to study the effect of electromagnetic radiation (EMR) on the excretion rates of stress hormones of medical staff in physiotherapy. The excretion rates of stress hormones cortisol, adrenaline and noradrenaline were followed during morning shift in 15 female physiotherapists using RIA kits and a spectrofluorimetric method. The mean number of treatments with EMR emitting devices per month and the emission of each device was assessed. A control group of nurses, matched by age, sex and work task was used. The psychosocial factors were evaluated and no differences between the two groups was found. Calculations of the individual EMR exposure show levels above the ICNIRP guidelines. Significantly higher excretion rates of cortisol, adrenaline and noradrenaline among the studied physiotherapists in comparison with the control group of nurses were found. In conclusion, our data showed that EMR influenced the excretion rates of stress hormones of medical staff in physiotherapy.  相似文献   

2.
This study was aimed to evaluate differences in the effect of microwave exposure on patients with depressive disorder and healthy subjects. Our experiments were carried out on a group of depressive patients (women, 18 subjects) and comparison group of healthy volunteers (women, 18 subjects) exposed during 30 min to 450 MHz microwave radiation modulated at 1,000 Hz frequency. The field power density at the scalp was 0.9 mW/cm2. As a subjective criteria of microwave effect, the Brief Affect Scale (BAS) and Visual Analogue Scale (VAS) before and after each exposure procedure were used. The analysis of EEG was performed and ratio of the EEG beta and theta power was selected as a measure for evaluation of the microwave effect. The BAS and VAS revealed rather improvement in subjective mood score after exposure for majority of depressive subjects (11) and no changes for others (7). The EEG analysis detected differences between calculated parameters for exposed and sham recordings in depression as well as healthy group. Statistically significant changes were introduced by microwave for five patients with depressive disorder and for one healthy subject. The rate of subjects affected by microwave in depression group (28%) was five times higher compared to that rate in healthy group (5.6%).  相似文献   

3.
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   

4.
Summary This study focuses on discrimination of changes, produced by low-level microwave exposure in intensity and time variability of the human EEG at rest. The power spectral density (PSD) method and nonlinear scaling analysis of the length distribution of low variability periods (LDLVP) were selected for analysis of the EEG signal. During the study, 19 healthy volunteers were exposed to a microwave (450 MHz) of 217 Hz frequency on-off modulation. The field power density at the scalp was 0.16 mW/cm2. The experimental protocol consisted of ten cycles of repetitive microwave exposure. Signals from frontal, temporal, parietal and occipital EEG channels on EEG theta, alpha and beta rhythms were analysed. Exposure to microwave causes average increase of EEG activity. LDLVP analysis discriminated significant effect in time variability for 2 subjects (11%). PSD method detected significant changes in intensity for 4 subjects (21%). The effect of low-level microwave exposure is stronger on EEG beta rhythm in temporal and parietal regions of the human brain.  相似文献   

5.
The health care staff operating magnetic resonance imaging (MRI) scanners are exposed to static magnetic field of significant spatial heterogenity and high level of flux density—usually existing permanently during the shift. The personnel can also be exposed to pulses of magnetic field of high rate of rise/fall, so-called gradient fields, which exist only during examination of patients. The level of workers’ exposure depends both on the type of the magnet and on the ergonomical characteristic of design of the particular MRI scanner. This paper presents the current state of the art on occupational exposure to static magnetic field health effects, gaps in scientific data, MRI workers’ exposure characteristics, research needs, and suggestions for the exposure assessment protocol for future investigations.  相似文献   

6.
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.
In the present study, a meta‐analysis was carried out to clarify the association between disinfection byproducts (DBPs) in drinking water and human cancer risk worldwide. Kidney, colorectal, esophagus, urinary bladder, brain, breast, leukemia, lung, and rectum cancers were selected to perform this analysis. According to preferred reporting items for systematic review and meta‐analysis protocol (PRISMA) guidelines, the relevant studies were identified and selection criteria (inclusion and exclusion criteria) were applied. Next, effective subgroups in these studies (gender, type of drinking water source, and type of DBPs) were analyzed. The quality of the studies was evaluated using the Newcastle‐Ottawa Scale. In addition, this overall study included analyses of 16 case–control and 3 cohort studies. The overall odds ratio (OR) with 95% confidence intervals (CI) between DBPs and cancer risk was 1.01 (95% CI, 0.94–1.09). The summary ORs of cancer risk were 1.04 (95% CI, 0.89–1.19) for kidney; 0.98 (95% CI, 0.87–1.09) for colorectal; 1.07 (95% CI, 0.84–1.29) for esophagus; 0.93 (95% CI, 0.80–1.06) for pancreatic; 1.00 (95% CI, 0.83–1.18) for brain; 1.13 (95% CI, 0.99–1.26) for breast; 0.93 (95% CI, 0.72–1.13) for leukemia; and 1.18 (95% CI, 1–1.36) for lung cancers. The results of this meta‐analysis suggested that there is not a significant association between DBPs in water and cancer risk. In addition, subgroup analysis shows a positive association with colorectal and kidney cancer risk in men, as well as colon and breast cancers in females. Studies of both genders have shown a significant association between lung and pancreatic cancers. Moreover, this study finds a significant relationship between cancer rate and consumers of city water and bottled water sources. In analyzing different types of DBPs in water, chlorine and trichloromethane show a significant association in increasing cancer risk.  相似文献   

8.
The effect of exposure to crude oil contaminated diet on the blood antioxidant defence system, lipid peroxidation, lipid profile as well as possible protective roles of vitamins E and C were studied in rabbits. Oxidative stress induction by crude oil was indicated by significantly (P < 0.05) increased lipid peroxidation and a non-significant (P < 0.05) decrease in superoxide dismutase and catalase activities. A similar pattern was also detected in the lipid profile: total cholesterol and LDL-cholesterol insignificantly (P < 0.05) increased while HDL-cholesterol and triglyceride significantly decreased relative to rabbits fed normal diet. The reciprocal relationship between HDL-cholesterol and LDL-cholesterol in addition to compromised antioxidant enzymes could predispose exposed animals to coronary heart disease. However, pre-treatment of the diet with vitamins C and E exhibited a protective role on the toxic effect of crude oil on lipid profile, lipid peroxidation as well as antioxidant enzymes. The order of protection was vitamin E + C > vitamin E > vitamin C. These observations seemed to suggest that the protective role of vitamins C and E is synergistic. The protective role of the vitamins is probably time-dependent as significant (P < 0.05) restoration of lipid profile as well as antioxidant enzymes activities to control values was effected after four weeks of exposure. It is therefore suggested that toxic effect of crude oil may be reduced by dietary supplementation of vitamins C and E.  相似文献   

9.
ABSTRACT: Snails, Goniobasis livescens (Menke), were exposed to acutely sublethal concentrations of p-nitrophenol and the lampricide, 3-triflourmethyl-4 nitrophenol(TFM), and then to acutely lethal thermal shocks. The same species were also exposed to acutely sublethal concentrations of zinc followed by exposure to acutely lethal concentrations of p-nitrophenol; and to acutely sublethal concentrations of TFM followed by exposure to acutely lethal concentrations of zinc. Brown trout, Salmo trutta, were exposed to acutely sublethal concentrations of TFM and then to an acutely lethal thermal shock. Results of these experiments indicate that prior exposure to acutely sublethal toxicant concentrations may reduce survival time for a subsequent exposure to acutely lethal concentrations of a second toxicant (e.g., snails exposed to Zn++ then p-nitrophenol) but neither prior or concomitant exposure to acutely sublethal toxicant concentrations insures that the median survival time for a lethal exposure will be significantly altered (e.g., snails exposed to 0.2 × 48 hour LC50 for TFM then Zn++). However, some acutely sublethal concentrations of a toxicant may significantly alter survival time of snails to a lethal concentration of a different toxicant (e.g., exposure to 0.4 × 48 hour LC50 TFM then a lethal dose of Zn++). The brown trout exposed to an acutely sublethal concentration of TFM and then an acutely lethal thermal shock did have significantly altered survival patterns.  相似文献   

10.
通过系统的监测了解吉林地区采油厂原油含水率分析仪的工作场所放射防护现状,为放射源监督管理部门提供参考依据,为保护环境、保护放射工作人员职业健康提供重要保障,为采油厂对辐射装置管理及措施提供依据。采用国家规定的标准方法对吉林省不同工作环境下的5家采油厂的45台原油含水率分析仪的周围剂量当量进行现场监测,对涉及接触原油含水率分析仪的4种不同岗位工作人员进行年有效剂量估算,对接触原油含水率分析仪的202名工作人员进行个人剂量监测。结果表明,原油含水率分析仪的工作场所周围剂量当量及人员受照剂量均满足国家标准要求,剂量分布较均匀,外输岗年有效剂量较小,集输岗年有效剂量较高。吉林省采油厂原油含水率分析仪在正常运行情况下,工作场所基本不会对工作人员造成职业照射,辐射防护状况良好,放射工作人员年有效剂量值均在国家规定限值范围内。  相似文献   

11.
Participatory environmental management can empower communities and enhance the sustainability of environmental interventions. However, existing power structures and inequalities along class, gender, or ethnic lines could prevent part of the community from accessing the full benefits of the intervention. An analysis of determinants of the willingness-to-participate in an environmental intervention in a Beirut neighborhood is conducted. Socioeconomic, health-risk distribution, and perception of community efficacy are used as predictors. A randomly selected sample of residents was surveyed. Respondents were asked to specify the frequency with which they were willing to be involved in an intervention to address priority environmental problems in the neighborhood. Bivariate and multivariate ordinal regression analyses were conducted. Tests of significance were based on the 95% confidence intervals (CI) of the odds ratio (OR). Males versus females (OR = 4.89, P < 0.001), respiratory patients versus nonsufferers (OR = 5.65, P < 0.001), tenants versus house owners (OR = 2.98, P < 0.01), and the less educated versus the more educated (OR = 2.42, P < 0.05) were significantly more likely to be willing to participate. The reluctance of female community members to participate might be a major hindrance to community-based environmental protection and special strategies must be devised to overcome it. On the other hand, respondents suffering from an illness perceived to be related to environmental toxins are likely to be strong participants in environmental conservation efforts. Finally, the study yielded no evidence that belief or lack of it in the efficacy of community action is a good predictor of the willingness-to-participate in such action.  相似文献   

12.
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   

13.
Fish are commonly used for monitoring the quality of waters receiving pulp mill effluents (PMEs). Isotopic assays of fish tissues have the potential to provide empirical evidence to link an effluent source to exposure. We show in a 45-d factorial laboratory experiment that different exposure pathways lead to isotopic signatures in fish tissue. Rainbow trout (Oncorhynchus mykiss) were exposed to 10% PME in three ways; direct exposure through addition of PME to aquaria, indirect exposure through invertebrate food consumption (Chironomus tentans cultured in 10% PME), and a combination of both exposure pathways. Of the four stable isotopes measured (delta13C, delta15N, delta34S, delta37Cl), delta13C, delta34S, and delta37Cl showed significant differences in exposed animal tissues. Delta37Cl of fish muscle tissue showed consistent differences across trophic levels and revealed contrasting pathways of PME exposure. Contrasting delta 37Cl values in C. tentans due to the presence or absence of 10% PME did not translate into delta37Cl differences in fish. Rather, delta37Cl ratios of fish muscle tissue were specifically related to 10% PME exposure in the aquaria (waterborne exposure pathway). Feasible distributions of 37Cl source contributions for observed mixture ratios confirmed that PME accounted for observed differences in delta37Cl among treatments. Direct uptake of chloride ions across gill surfaces is the most likely pathway for assimilation of PME into fish tissues. Considering the variability of PMEs and receiving environments, use of a multi-isotope approach is recommended for tracing exposure of fish. Use of 37Cl should also be considered in light of its alternative assimilation pathway.  相似文献   

14.
Traditional corn (Zea mays L.) (TC), the primary grain used in swine (Sus scrofa) diets, stores a majority of its P as phytate, which is largely unavailable for digestion by nonruminant animals. Low-phytate corn (LPC) contains similar amounts of total P but a smaller percentage of P as phytate. When fed to swine, LPC increases P utilization and reduces P content of manure. While differences in P content between manure from animals fed TC and LPC diets have been documented, solubility and lability of manure P have not been compared. Manure P was characterized in manure from swine fed either LPC or TC diets in 2000 and 2001. Total P was lower (20 vs. 34 g kg(-1)) and N to P ratio was higher (4.5 vs. 3.3) in LPC manure than in TC manure. Manures were sequentially extracted with deionized water, 0.5 M NaHCO3, 0.1 M NaOH, and 1.0 M HCl. Extracts were analyzed for inorganic and total P. Most P (approximately 80%) in the extracts was in the inorganic form. Concentration of P in the water-extractable fraction was lower for LPC manure (10.2 g kg(-1) in 2000 and 9.7 g kg(-1) in 2001) than for TC manure (13.6 g kg(-1) in 2000 and 17.0 g kg(-1) in 2001). Percentage of total P in each extract was in the order of: H2O (60%), HCl (22%), NaHCO3 (12%), NaOH (8%), and residue (<1%). Total P and distribution of P in extracts indicates swine are able to utilize more P contained in LPC feed but the composition of P excreted in LPC manure is similar to TC manure. Solubility, crop availability, and lability of P in LPC manure should be similar to that of TC manure.  相似文献   

15.
ABSTRACT: The spatial and temporal variability of hydroclimatic elements were investigated in the central and northern Rocky Mountains (Colorado, Idaho, Montana, Utah, and Wyoming) during the 1951–1985 period. The three hydroclimatic elements studied were total water-year (October 1-September 30) streamflow (ST), winter (October 1-March 31) accumulated precipitation (PR), and April 1 snowpack (SN). An analysis of 14 virgin watersheds showed wide spatial djfferences in the temporal variability of SN, PR, and ST, and these were found to be caused largely by basin exposure to moist air flows. The more stable (low variability) basins were those exposed to prevailing northerly to westerly flow, while unstable (high variability) basins were exposed to occasional southwesterly to southeasterly moist flow. Snowpack was the better indicator of ST in 11 of the 14 watersheds, explaining 37 to 87 percent of the ST variance. Analysis of the spatial variability, based on all SN and PR data from across the study area, revealed 11 discrete climatic regions. Both SN and PR exhibited coherent regions of stable and unstable temporal variability. The average variability between stable and unstable regions differed by a factor of two, and the differences were best explained by the exposure of the mountain barrier to moist air flows.  相似文献   

16.
Based on regional heterogeneity of environmental characteristics and factors influencing those characteristics, environmental units may be classified into homogeneous zones. Then, essential strategies and mitigation measures in each zone may be developed and environmental quality may be holistically improved using a system of environmental management regionalization (EMRZ). Here, an EMRZ scheme for China was devised by outlining regional management using integrated qualitative and quantitative methods. First, the land was subdivided into four environmental management domains using China’s three physical geographic domains. Second, using a regionalization indicator system, the environmental characteristics of neighboring provinces in four domains was quantified using the one-dimensional Euclidean distance method; regions with high similarity were merged into one environmental management region (EMR) and the preliminary draft of EMRs was obtained. Based on the preliminary scheme, eight EMRs using prefecture-level administrative regions were obtained through boundary adjustment based on important natural geographical boundaries and existing regional plans. These include the Northeastern China Region, the North China Plain Region, the Loess Plateau Region, Southeast Coast Region, the Middle Reaches of the Yangtze River, the Southwestern China Region, the Northwestern China Region, and the Tibetan Plateau Region. Priority environmental problems of each EMR were discussed. The main contribution of this study is that it develops a novel methodological framework for EMRZ integrating qualitative and quantitative methodologies, and considers the spatial contiguity of each EMR and the spatial integrity of each administrative unit. Future research will focus on priority goals and establishment of suitable environmental management policies for each EMR based on known local environmental problems.  相似文献   

17.
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   

18.
To test the injection behaviour of CO2 into brine-saturated rock and to evaluate the dependence of geophysical properties on CO2 injection, flow and exposure experiments with brine and CO2 were performed on sandstone samples of the Stuttgart Formation representing potential reservoir rocks for CO2 storage. The sandstone samples studied are generally fine-grained with porosities between 17 and 32% and permeabilities between 1 and 100 mD.Additional batch experiments were performed to predict the long-term behaviour of geological CO2 storage. Reservoir rock samples were exposed over a period of several months to CO2-saturated reservoir fluid in high-pressure vessels under in situ temperature and pressure conditions. Petrophysical parameters, porosity and the pore radius distribution were investigated before and after the experiments by NMR (Nuclear Magnetic Resonance) relaxation and mercury injection. Most of the NMR measurements of the tested samples showed a slight increase of porosity and a higher proportion of large pores.  相似文献   

19.
On experimental setup in bioelectromagnetics   总被引:1,自引:1,他引:0  
Bioeffects created by electromagnetic field (EMF) are the subject of intensive studies. This paper critically considers estimations of exposure to EMF in bioelectromagnetic experiments. Results of calculations presented herein show the significant role of the presence of conducting bodies (the exposure system) near an object under test on EMF energy absorption as well as mutual interactions between simultaneously exposed objects. Our aims herein are twofold: firstly to find a way to refer measurement results to free-space conditions in order to enable comparison of results obtained in different laboratories, and secondly to show that EMF energy absorption in any exposed object is different and that this difference is a function of the size of the exposure system, the number of exposed objects, and the particular properties (i.e., the electromagnetic structure) of the objects. In the authors’ opinion the existence of interactions caused by the presence of the exposure system and other exposed objects is a reason why remarkable differences are observed between experiments performed even under supposedly identical conditions. The presented considerations and conclusion suggest wider participation of physicists and engineers in bioelectromagnetic experiments in order to ensure the correctness of metrological aspects of these experiments.  相似文献   

20.
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   

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