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1.
    
The present study investigates the effects of a weak (+/-200 microT(pk)), pulsed, extremely low frequency magnetic field (ELF MF) upon the human electroencephalogram (EEG). We have previously determined that exposure to pulsed ELF MFs can affect the EEG, notably the alpha frequency (8-13 Hz) over the occipital-parietal region of the scalp. In the present study, subjects (n = 32) were exposed to two different pulsed MF sequences (1 and 2, used previously) that differed in presentation rate, in order to examine the effects upon the alpha frequency of the human EEG. Results suggest that compared to sham exposure, alpha activity was lowered over the occipital-parietal regions of the brain during exposure to Sequence 1, while alpha activity over the same regions was higher after Sequence 2 exposure. These effects occurred after approximately 5 min of pulsed MF exposure. The results also suggest that a previous exposure to the pulsed MF sequence determined subjects' responses in the present experiment. This study supports our previous observation of EEG changes after 5 min pulsed ELF MF exposure. The results of this study are also consistent with existing EEG experiments of ELF MF and mobile phone effects upon the brain.  相似文献   

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Continuing evidence suggests that extremely low frequency magnetic fields (ELF MFs) can affect animal and human behavior. We have previously demonstrated that after a 15 min exposure to a pulsed ELF MF, with most power at frequencies between 0 and 500 Hz, human brain electrical activity is affected as measured by electroencephalography (EEG), specifically within the alpha frequency (8-13 Hz). Here, we report that a pulsed ELF MF affects the human EEG during the exposure period. Twenty subjects (10 males; 10 females) received both a magnetic field and a sham session of 15 min in a counterbalanced design. Analysis of variance (ANOVA) revealed that alpha activity was significantly lower over the occipital electrodes (O1, Oz, O2) [F(1,16) = 5.376, P < .01, eta2 = 0.418] after the first 5 min of magnetic field exposure and was found to be related to the order of exposure (MF-sham vs. sham-MF). This decrease in alpha activity was no longer significant in the 1st min post-exposure, compared to sham (P > .05). This study is among the first to assess EEG frequency changes during a weak (+/-200 microTpk), pulsed ELF MF exposure.  相似文献   

3.
    
Normative data on the in vivo size of the human brain and its major anatomically defined subdivisions are not readily available. In this study, high-resolution magnetic resonance imaging was used to measure regional brain volumes in 46 normal, right-handed adults (23 men, 23 women) between the ages of 22-49 years. Parcellation of the brain was based on neuroanatomical landmarks. The following brain regions were measured: the cerebral hemispheres, frontal lobe, temporal lobe, parietal lobe, occipital lobe, cingulate gyrus, insula, cerebellum, corpus callosum, and lateral ventricles. Males tend to be significantly larger than females, for the whole brain and for nearly all of its major subdivisions, including the corpus callosum. However, the proportional sizes of regions relative to total volume of the hemisphere are remarkably similar in males and females. Variation in size of region is always greater than variation in proportional representation. Asymmetries in brain regions are not profound, with the exception of the cingulate gyrus, which is larger in the left hemisphere. Brain regions are highly correlated in size, with the exception of the lateral ventricles. After controlling for hemisphere size, the volumes of the frontal and parietal lobes are significantly negatively correlated. The occipital lobe tends to be less sexually dimorphic than other major lobes, and less correlated with other brain regions for volume. These results have implications for understanding whether or not certain sectors of the brain have shown relative expansion over the course of hominid and hominoid evolution.  相似文献   

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We study the effect of microwaves at 2,450 MHz on protein unfolding using surface plasmon resonance sensing. Our experimental method makes use of the fact that unfolding proteins tend to bind to chaperones on their unfolding pathway and this attachment is readily monitored by surface plasmon resonance. We use the protein citrate synthase (CS) for this study as it shows strong binding to the chaperone alpha crystallin when stressed by exposure to excess temperature. The results of microwave heating are compared with the effect of ambient heating and a combination of ambient and microwave heating to the same final temperature. We study the temperature distributions during the heating process. We show that microwaves cause a significantly higher degree of unfolding than conventional thermal stress for protein solutions heated to the same maximum temperature.  相似文献   

6.
《人体电磁兼容系统与电磁场处理水》一文分三篇写。第一篇“Ⅰ.人体电磁兼容系统”,讨论了人体体内电磁场;第二篇“Ⅱ·电磁水的特性”,讨论了电磁水的电磁场。二文均已发表于《生物磁学》。本文是第三篇,讨论电磁水电磁场对人体电磁场的作用,重点阐明饮用电磁水后,主要是电磁水的电磁场作为入射场与体内场发生迭加作用,产生耦合电磁场,从而实现其对体内场的调节作用,达到维系身体健康的目的。由于有关水的问题非常复杂,动态性强,故大多数关于耦合场的研究均服从于“统计学规律”。  相似文献   

7.
         下载免费PDF全文
Bovine is very common in Quaternary hominid sites in China with abundant fossil specimens. But there are still many controversies of the identification and classification. Isolated teeth are the most very often finds at cave sites in South China, so the problems about the identification of Bovine are particularly acute. The present paper describes the fossil Bovine from Bailong Cave in Hubei Province. There are a large quantity of isolated teeth, broken crania, horn-cores, mandibles and post cranial bones. The remarkable characters of these fossils are as follows: horn-cores short and strong, dorsoventrally elliptical in cross-section; frontals arched and rised between the horn-cores; parietals retreat from face frontails; occipitals round and relatively high; postcornual constriction is quite narrow and the temporal fossae have strong depressions; the angle of mandible is over 90°and the mandibular ramus leans backward; morphological complexity of p2 is between that of Bubalus and Bos (Bos) taurustaurus. Based on the morphological characters and dimensions, these fossils are referred to Bos (Bibos) gaurus. Bailong Cave has the most abundant specimens of Bos (Bibos) gaurus in China, which offer the important evidences to distinguish the Bovine fossils from Cave sites in South China.  相似文献   

8.
牛亚科动物在中国第四纪古人类遗址中十分常见,但其分类和鉴定仍存在诸多问题。南方洞穴动物群经常仅有单个牙齿保存,所以南方更新世洞穴遗址中牛亚科动物化石鉴别问题更为突出。湖北郧西白龙洞古人类遗址出土的大型牛亚科动物化石,不仅有大量单个牙齿,还有残破颅骨、角心、下颌骨及头后骨骼。白龙洞的牛亚科动物角心粗短、横截面呈背腹略扁的椭圆形;额骨上的角间隆突发育且呈拱形;顶骨从颅顶退出;枕面较圆且高;角后颅骨收缩强烈使得枕骨上部变窄,颞窝明显凹进;下颌角大于90°,下颌支向后倾斜;下颌p2的结构复杂程度介于水牛Bubalus和黄牛Bos(Bos)taurus之间。依据上述特征,可将白龙洞的大型牛亚科动物化石归入大额牛Bos(Bibos)gaurus。白龙洞是我国出土大额牛化石最为丰富的古人类遗址,为区分南方洞穴出土的牛亚科动物化石提供了重要材料。  相似文献   

9.
    
Currently, there is debate as to whether ponto-geniculo-occipital (PGO) waves or the resulting cortical arousal associated with such neural activity constitute the biological substrate of dreaming. The present study aimed to induce PGO activity in humans using an external stimulation technique. Participants (N = 15) were presented with tones (1,000 Hz) of increasing intensity during Stage II and rapid eye movement (REM) sleep. A peizosensor fixed to the eyelid captured ocular activity (OA) as an indicator of PGO activity in response to the tone. Compared to the stimulation, the Stage II control condition with no Stage II tone-induced ocular activity (OA) condition showed: a) more imagery reports that were rated as more vivid, and b) more electroencephalogram (EEG) arousal time. EEG arousal was correlated with the average Stage II imagery across participants. None of these findings were observed from REM sleep. It was concluded that investigation of PGO analogues, or even PGO activity itself, and dreaming might be inherently flawed due to the confounding presence of EEG arousal, as the two may be intimately linked. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

10.
The effect of a 16-Hz electromagnetic field on the mobility of the diatom Amphora coffeaformis was examined on agar plates that contained no added calcium and also on agar plates containing 0.25 or 2.5 mM exogenous Ca2+. Exposure conditions consisted of an ac field of 16 Hz with an amplitude of 20.9 microT parallel to the horizontal component of the dc field (BH = 20.9 microT, where BV = 0). To assess results, the percentage of diatoms that moved a distance greater than their body length was determined. We observed the field-associated increase in diatom motion at 0.25 mM Ca++, which was previously reported in the literature. Although the magnitude of the effect at 16 Hz was significant, the percentage of cells that moved was not sufficiently reproducible to allow examination for frequency dependence.  相似文献   

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12.
Li  Yu. V.  Terekhova  L. P.  Alferova  I. V.  Galatenko  O. A.  Gapochka  M. G. 《Microbiology》2003,72(1):114-117
A new method employing succession analysis and extremely high frequency (EHF) irradiation is proposed for the selective isolation of actinomycetes from soil. Total actinomycetes were efficiently isolated from soil suspensions irradiated in the wavelength band 4.6–5.8 mm on the 14th and 45th days of succession initiated by soil wetting and from soil suspensions irradiated in the wavelength band 8–11.5 mm on the 7th day of succession. The rare actinomycete genera Actinomadura, Micromonospora, Nonomuraea, Microbispora, Amycolatopsis, Pseudonocardia, Saccharothrix, Streptosporangium, Actinosynnema, Nocardioides, and Saccharopolyspora were isolated by either of the two approaches (succession analysis and EHF irradiation); however, the range of isolated rare actinomycetes was considerably wider when a combination of the two approaches was used. For instance, actinomycetes of the rare genera Actinocorallia, Promicromonospora, Actinoplanes, and Kibdelosporangium were isolated only when EHF irradiation was employed at the early stages of succession.  相似文献   

13.
The minute-range up and down rhythms of the lateral leaflets of Desmodium gyrans has been studied when exposed to electromagnetic radiation in the radio-frequency (RF) range. The RF radiation was applied as homogeneous 27.12 MHz fields in specially-designed exposure cells(and in some cases as non-homogeneous radiation of 27 MHz. amplitude modulated by 50 Hz, in front of commercial diathermy equipment). All fields were applied as pulses. We report effects in the leaflet rhythms such as temporary changes in the amplitude, period, and phase. The radiation could also cause temporary or complete cessations of the rhythms. The lowest dose (8 W/cm2) used was still effective. © 1993 Wiley-Liss. Inc.  相似文献   

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Two mechanisms (bubble and resonance) of the interaction of low-intensity millimeter electromagnetic radiation and model cellular systems are investigated based on the example of Saccharomyces cerevisiae. It is shown that the effect of stimulating cell activity through electromagnetic radiation is of a pronounced resonance nature. The effect caused by the stimulation of vital activity in yeast cells under the influence of a thermal pulse, which can be described in terms of the bubble mechanism, is presented. The possibility of implementing both mechanisms is shown.  相似文献   

16.
特定电磁波对小麦幼苗膜脂肪酸组成的影响   总被引:4,自引:0,他引:4       下载免费PDF全文
本文研究了特定电磁波处理小麦种子对其幼苗叶片的总膜脂肪酸组成及线粒体膜脂肪酸组成的影响。在正常情况下,TDP处理的总膜脂肪酸组成及线粒体膜脂肪酸组成与对照的区不大。  相似文献   

17.
    
Organisms are exposed to electromagnetic fields from the introduction of wireless networks that send information all over the world. In this study we examined the impact of exposure to the fields from mobile phone base stations (GSM 900?MHz) on the reproductive capacity of small, virgin, invertebrates. A field experiment was performed exposing four different invertebrate species at different distances from a radiofrequency electromagnetic fields (RF EMF) transmitter for a 48-h period. The control groups were isolated from EMF exposure by use of Faraday cages. The response variables as measured in the laboratory were fecundity and number of offspring. Results showed that distance was not an adequate proxy to explain dose-response regressions. No significant impact of the exposure matrices, measures of central tendency and temporal variability of EMF, on reproductive endpoints was found. Finding no impact on reproductive capacity does not fully exclude the existence of EMF impact, since mechanistically models hypothesizing non-thermal-induced biological effects from RF exposure are still to be developed. The exposure to RF EMF is ubiquitous and is still increasing rapidly over large areas. We plea for more attention toward the possible impacts of EMF on biodiversity.  相似文献   

18.
Luc Montagnier博士研究小组发现:某些病原微生物的DNA在高倍稀释的水溶液中可共振产生低频电磁波。这种低频率的电磁辐射被称作EMS。许多病原微生物的培养基或者感染患者的血浆经过滤和稀释后可以检测到EMS。在HIV患者中,HIVDNA也可以用EMS检测到。这些DNA的存在反应了HIV的复制有可能以DNA-DNA的形式进行,这些DNA也可能是HIV病毒储库的组成部分。  相似文献   

19.
Abstract

The objective was to test the influence of a pulsed electromagnetic field (PEMF) on bacterial biofilm colonization around implants incorporated with healing abutments. Healing abutments with (test group) and without (control group) active PEMF devices were placed in a multispecies biofilm consisting of 31 different bacterial species. The biofilm composition and total bacterial counts (x105) were analyzed by checkerboard DNA-DNA hybridization. After 96?h, the mean level of 7 out of the 31 bacterial species differed significantly between groups, namely Eubacterium nodatum, Fusobacterium nucleatum ssp. nucleatum, Streptococcus intermedius, Streptococcus anginosus, Streptococcus mutans, Fusobacterium nucleatum ssp. Vicentii and Capnocytophaga ochracea were elevated in the control group (p?<?0.05). The mean total bacterial counts were lower in the Test group vs the control group (p?<?0.05). An electromagnetic healing cap had antimicrobial effects on the bacterial species and can be used to control bacterial colonization around dental implants. Further clinical studies should be conducted to confirm these findings.  相似文献   

20.
    
Research on long‐term exposure to electromagnetic fields on cognition is lacking. We investigated the associations between frequent digital mobile phone use and global and domain‐specific cognitive changes in older persons, a vulnerable group experiencing age‐associated cognitive decline. We assessed 871 non‐demented Chinese participants in the Singapore Longitudinal Ageing Studies cohort on the frequency of digital mobile phone use, neurocognitive performance and confounding variables at baseline, and neurocognitive performance at the 4‐year follow‐up. Findings showed that digital mobile phone users were typically self‐selected to possess characteristics favoring better cognitive functioning and concomitantly demonstrate better performance on cognitive tasks. There was evidently no significant deleterious effect of digital mobile phone use on cognitive functioning in older people. Findings suggest, however, that digital mobile phone use may have an independent facilitating effect on global and executive functioning. Bioelectromagnetics 33:176–185, 2012. © 2011 Wiley Periodicals, Inc.  相似文献   

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