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941.
Attila Trunk Gábor Stefanics Norbert Zentai Zsófia Kovács‐Bálint György Thuróczy István Hernádi 《Bioelectromagnetics》2013,34(1):31-42
Potential effects of a 30 min exposure to third generation (3G) Universal Mobile Telecommunications System (UMTS) mobile phone‐like electromagnetic fields (EMFs) were investigated on human brain electrical activity in two experiments. In the first experiment, spontaneous electroencephalography (sEEG) was analyzed (n = 17); in the second experiment, auditory event‐related potentials (ERPs) and automatic deviance detection processes reflected by mismatch negativity (MMN) were investigated in a passive oddball paradigm (n = 26). Both sEEG and ERP experiments followed a double‐blind protocol where subjects were exposed to either genuine or sham irradiation in two separate sessions. In both experiments, electroencephalograms (EEG) were recorded at midline electrode sites before and after exposure while subjects were watching a silent documentary. Spectral power of sEEG data was analyzed in the delta, theta, alpha, and beta frequency bands. In the ERP experiment, subjects were presented with a random series of standard (90%) and frequency‐deviant (10%) tones in a passive binaural oddball paradigm. The amplitude and latency of the P50, N100, P200, MMN, and P3a components were analyzed. We found no measurable effects of a 30 min 3G mobile phone irradiation on the EEG spectral power in any frequency band studied. Also, we found no significant effects of EMF irradiation on the amplitude and latency of any of the ERP components. In summary, the present results do not support the notion that a 30 min unilateral 3G EMF exposure interferes with human sEEG activity, auditory evoked potentials or automatic deviance detection indexed by MMN. Bioelectromagnetics 34:31–42, 2013. © 2012 Wiley Periodicals, Inc. 相似文献
942.
943.
Edward Błaszczak Andrzej Franek Jakub Taradaj Jerzy Widuchowski Jerzy Klimczak 《Bioelectromagnetics》2009,30(2):152-158
The purpose of this clinical study was to assess low frequency, low intensity magnetic fields in the enhancement of the physical rehabilitation of patients after knee endoprosthesis surgery. The study included 62 patients who underwent total knee arthroplasty. Group A consisted of 32 patients who were physically rehabilitated. Group B consisted of 30 patients who were physically rehabilitated and treated additionally with pulsing magnetic fields (5 mT, 30 Hz, 20 min once a day, 5 days weekly). Therapy lasted 3 weeks for both groups. The rehabilitation process was evaluated using a goniometer, tensometer, goniometric pendulum test, Lysholm scale for knee function, and a visual analogue scale (VAS) questionnaire for pain and activity. The changes of measured rates were comparable in both groups. Low frequency and low intensity magnetic fields of examined parameters were not demonstrated to effectively improve the rehabilitation of patients after knee endoprosthesis surgery. Bioelectromagnetics 30:152–158, 2009. © 2008 Wiley‐Liss, Inc. 相似文献
944.
MARK A. DAVIS PETER B. REICH† MARY J. B. KNOLL LEE DOOLEY MARJORIE HUNDTOFT INGRID ATTLESON 《Global Change Biology》2007,13(11):2308-2316
It has been hypothesized that elevated levels of atmospheric CO2 (eCO2) may facilitate the encroachment of woody plants into grasslands by reducing water stress. In east‐central Minnesota, sandy soils frequently create drought conditions for plants, and water limitation inhibits the establishment of oaks into old fields situated on these soils. Some have argued that eCO2 should slow secondary succession by favoring fast‐growing early successional species. However, if oak encroachment into old fields is being inhibited by water stress, then eCO2 could accelerate old‐field succession in this region. The purpose of this study was to test the hypothesis that eCO2 will increase the establishment success of oak seedlings in an old field environment. The study was conducted with CO2 levels controlled by free air CO2 enrichment (FACE). In May 1999, four oak (Quercus ellipsoidalis) acorns were planted in each of 24 plots in each of six experimental FACE rings (n= 576), three of which received elevated levels (550 ppm) of CO2. Half the plots in each ring were weeded during the first three summers of the experiment. In summer 2000, water input was manipulated during a 3.5‐week period, during which half the plots received regular watering while the other half received no water. Summer 2001 was dry, receiving 35% less rainfall than the mean level. Under hot and dry conditions, eCO2 increased soil water levels in unweeded plots and enhanced oak establishment (survival and growth) in weeded plots. In 2006, after the eighth growing season following planting, survival was five times greater under elevated than ambient CO2. The results showed that under hot and dry conditions, eCO2 can act like a nurse plant for tree seedlings growing in bare and unshaded areas, increasing seedling survival and growth, and thereby expanding the establishment window for trees encroaching into a grassland environment. 相似文献
945.
The aim of our work was to study the working‐age population's self‐reported physical symptoms associated with using mobile phones and other electrical devices. A qualitative method was applied using an open‐ended question in a questionnaire, which included questions about the possible influence of new technical equipment on health. We then created subgroups of respondents for different self‐reported symptoms associated with mobile phones and other electrical devices. The research questions were: (1) how the respondents described physical symptoms associated with using mobile phones and other electrical devices and (2) how the answers can be classified into subgroups based on symptoms or devices. We identified the following categories: (1) respondents with different self‐reported symptoms which they associated with using mobile phones (headache, earache, or warmth sensations), (2) respondents who had skin symptoms when they stayed in front of a computer screen, (3) respondents who mentioned physical symptoms associated with using mobile phones and other electrical devices. Total prevalence of self‐reported physical symptoms associated with using mobile phones and other electrical devices (categories 1 and 2) was 0.7%. In the future it will be possible to obtain new knowledge of these topics by using qualitative methods. Bioelectromagnetics 30:431–437, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
946.
Measurements were made of the small, transient offsets of vacuolar potential produced in single cells of Nitella flexilis and Chara braunii by isolated bursts of audio frequency electromagnetic radiation. The offsets increased in magnitude with decreasing frequency of the electromagnetic radiation and, below about 6 kHz, seemed to approach a lowfrequency asymptote. This frequency dependence for the offset is shown to be in accordance with a previously developed model in which the incident radiation is weakly rectified by the cell's membrane system. 相似文献
947.
Gowrishankar TR Esser AT Vasilkoski Z Smith KC Weaver JC 《Biochemical and biophysical research communications》2006,341(4):1266-1276
Conventional electroporation (EP) by 0.1 to 1 kV/cm pulses longer than 100 micros, and supra-electroporation by 10 to 300 kV/cm pulses shorter than 1 micros cause different cellular effects. Conventional EP delivers DNA, proteins, small drugs, and fluorescent indicators across the plasma membrane (PM) and causes moderate levels of phosphatidylserine (PS) translocation at the PM. We hypothesize that supra-EP is central to intracellular effects such as apoptosis induction and higher levels of PS translocation. Our cell system model has 20,000 interconnected local models for small areas of the PM and organelle membranes, small regions of aqueous media, appropriate resting potentials, and the asymptotic EP model. Conventional EP primarily affects the PM, but with a hint of endoplasmic reticulum involvement. Supra-EP can involve all of a cell's membrane at the largest fields. Conventional EP fields tend to go around cells, but supra-EP fields go through cells, extensively penetrating organelles. 相似文献
948.
Structured additive regression for categorical space-time data: a mixed model approach 总被引:1,自引:0,他引:1
Motivated by a space-time study on forest health with damage state of trees as the response, we propose a general class of structured additive regression models for categorical responses, allowing for a flexible semiparametric predictor. Nonlinear effects of continuous covariates, time trends, and interactions between continuous covariates are modeled by penalized splines. Spatial effects can be estimated based on Markov random fields, Gaussian random fields, or two-dimensional penalized splines. We present our approach from a Bayesian perspective, with inference based on a categorical linear mixed model representation. The resulting empirical Bayes method is closely related to penalized likelihood estimation in a frequentist setting. Variance components, corresponding to inverse smoothing parameters, are estimated using (approximate) restricted maximum likelihood. In simulation studies we investigate the performance of different choices for the spatial effect, compare the empirical Bayes approach to competing methodology, and study the bias of mixed model estimates. As an application we analyze data from the forest health survey. 相似文献
949.
稻田甲螨的分类学研究(蜱螨亚纲:真螨目:甲螨亚目) 总被引:1,自引:0,他引:1
报道稻田甲螨种类共计30科36属42种,其中包括枝姣奥甲螨Pulchroppia(Pulchroppia)ramifera Wang et Li,sp.nov.。地枝奥甲螨Ramusella(Insculptoppia)humico-la Wang et Li,sp.nov.和长纹合若甲螨Zygoribatula longilinea Wang et Li,sp.nov.3新种,丝管囊甲螨Sacculozetes filosus Behan-Pelletier,1991,和尖足肋甲螨Podoribates cuspidatusSakakibara et Aoki,1966,2新纪录,此外,还提出一项新名Pulchroppia(Pulchroppia)mahunkai Wang et Li.本文除对新种和新纪录详细描述,对重要的优势种进行重描述外,还对稻田甲螨种群结构特点和存在争议的种类进行了讨论。 相似文献
950.
Wallace D Eltiti S Ridgewell A Garner K Russo R Sepulveda F Walker S Quinlan T Dudley S Maung S Deeble R Fox E 《Bioelectromagnetics》2012,33(1):23-39
Terrestrial Trunked Radio (TETRA) technology (“Airwave”) has led to public concern because of its potential interference with electrical activity in the brain. The present study is the first to examine whether acute exposure to a TETRA base station signal has an impact on cognitive functioning and physiological responses. Participants were exposed to a 420 MHz TETRA signal at a power flux density of 10 mW/m2 as well as sham (no signal) under double‐blind conditions. Fifty‐one people who reported a perceived sensitivity to electromagnetic fields as well as 132 controls participated in a double‐blind provocation study. Forty‐eight sensitive and 132 control participants completed all three sessions. Measures of short‐term memory, working memory, and attention were administered while physiological responses (blood volume pulse, heart rate, skin conductance) were monitored. After applying exclusion criteria based on task performance for each aforementioned cognitive measure, data were analyzed for 36, 43, and 48 sensitive participants for these respective tasks and, likewise, 107,125, and 129 controls. We observed no differences in cognitive performance between sham and TETRA exposure in either group; physiological response also did not differ between the exposure conditions. These findings are similar to previous double‐blind studies with other mobile phone signals (900–2100 MHz), which could not establish any clear evidence that mobile phone signals affect health or cognitive function. Bioelectromagnetics 33:23–39, 2012. © 2011 Wiley Periodicals, Inc. 相似文献