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Adult male rats were continuously exposed or sham-exposed to a 25-Gauss, 100-Hz magnetic field for 1, 2, or 4 weeks. Hematologic, serum chemistry, pituitary, gonadal and adrenal functions were examined. No effects were observed on body and organ weights or hematologic and serum chemistry levels, except for an increase in leukocytes after 4 weeks of exposure. The pituitary levels of prolactin, adrenocorticotropin (ACTH) and total proteins showed a statistically significant increase in animals exposed for 4 weeks. The ACTH levels in serum were significantly. decreased after 4 weeks of exposure.  相似文献   

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Pulsing electromagnetic field (PEMF) therapy may be a viable form of complementary and alternative medicine. Clinical applications include the treatment of fractures, wounds, and heart disease. More recent applications involve treatment of recurrent headache disorders. This paper reviews available studies investigating PEMF for headache management. Possible mechanisms for effects (neurochemical, electrophysical, and cardiovascular) are discussed. The available data suggest that PEMF treatment for headache merits further study. Suggestions for future research are provided.  相似文献   

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社会治理是基于对本社会管理过程中权力格局分析与判断,在政府、市场、社会与公民基关系明确定位的前提下倡导的新型公共管理模式,由于其对公众利益和责任表达、解决突出社会矛盾问题具有针对性和优越性,已得到普遍促进和应用。试图通过对国内外社会治理理论进展、内涵归纳以及医疗卫生领域社会治理有效路径和实践探索的梳理分析,提出了在医疗卫生领域探讨和开发其社会治理效用和适宜路径的思考建议。  相似文献   

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Objectives

To estimate the relationship between exposure to extremely low-frequency electromagnetic fields (ELF-EMF) and the risk of amyotrophic lateral sclerosis (ALS) by a meta-analysis.

Methods

Through searching PubMed databases (or manual searching) up to April 2012 using the following keywords: “occupational exposure”, “electromagnetic fields” and “amyotrophic lateral sclerosis” or “motor neuron disease”, seventeen studies were identified as eligible for this meta-analysis. The associations between ELF-EMF exposure and the ALS risk were estimated based on study design (case-control or cohort study), and ELF-EMF exposure level assessment (job title or job-exposure matrix). The heterogeneity across the studies was tested, as was publication bias.

Results

Occupational exposure to ELF-EMF was significantly associated with increased risk of ALS in pooled studies (RR = 1.29, 95%CI = 1.02–1.62), and case-control studies (OR = 1.39, 95%CI = 1.05–1.84), but not cohort studies (RR = 1.16, 95% CI = 0.80–1.69). In sub-analyses, similar significant associations were found when the exposure level was defined by the job title, but not the job-exposure matrix. In addition, significant associations between occupational exposure to ELF-EMF and increased risk of ALS were found in studies of subjects who were clinically diagnosed but not those based on the death certificate. Moderate heterogeneity was observed in all analyses.

Conclusions

Our data suggest a slight but significant ALS risk increase among those with job titles related to relatively high levels of ELF-EMF exposure. Since the magnitude of estimated RR was relatively small, we cannot deny the possibility of potential biases at work. Electrical shocks or other unidentified variables associated with electrical occupations, rather than magnetic-field exposure, may be responsible for the observed associations with ALS.  相似文献   

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Idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) is a controversial condition in which people describe symptoms following exposure to electromagnetic fields from everyday electrical devices. However, double-blind experiments have found no convincing evidence that electromagnetic fields cause these symptoms. In this study, we assessed whether recent newspaper reporting in the UK reflected this scientific evidence. We searched a database of newspaper articles to identify all those that contained IEI-EMF related keywords and selected a random sample of 60 for content analysis. For our primary outcomes, we assessed how many articles mainly or wholly presented an electromagnetic cause for IEI-EMF and how many discussed unproven treatments for the condition such as strategies intended to reduce exposure to electromagnetic fields or the use of complementary and alternative therapies. We also assessed whether the type of information source used by a newspaper article (e.g. scientist, person with IEI-EMF, politician) or the type of newspaper (broadsheet, tabloid, local or regional) was associated with either outcome. Of the 60 articles, 43 (71.7%) presented a mainly electromagnetic cause, compared to 13 (21.7%) which presented mainly non-electromagnetic causes and 4 (6.7%) which did not discuss a cause. 29 (48.3%) did not mention any potential treatment, while 24 (40.0%) mentioned eletromagnetic field related strategies and 12 (20.0%) mentioned complementary or alternative therapies. Articles which quoted someone with IEI-EMF were significantly more likely to report an electromagnetic cause and to present unproven treatments. Those which used a scientist as a source were more likely to present a non-electromagnetic cause for the condition. The widespread poor reporting we identified is disappointing and has the potential for to encourage more people to misattribute their symptoms to electromagnetic fields. Scientists should remain engaged with the media to counteract this effect.  相似文献   

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Contemporary cognitive and neuropsychological approaches to dreaming show striking methodological and conceptual similarities with the scientific dream literature of the last century. The use of introspective dream reports and the emphasis on dream phenomenology are characteristic of both periods but were bannished during the first half of this century, the former by behaviorism, the latter by psychoanalysis. Three main common axioms of 19th century and contemporary dream research are described: (a) dream experience results from cognitive syntheses realized in the absence of external constraints; (b) dream narrative or dream coherency involves mental associative mechanisms; (c) dream bizarreness emerges from a cerebral state characterized by functional dissociation. According to these three axioms, the observation of dream phenomena reveals that distinct cognitive processes might function in a partly autonomous, automatic, and dissociated way, making dreaming a unique model of these cognitive processes.  相似文献   

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Technologies based on extremely highfrequency electromagnetic fields, inparticular in the terahertz region, arequite recent and new to the public. While anumber of advantages have been shown,especially in the biomedical area,biological effects and possible healthimplications have not been fullyinvestigated. The experience gained withelectromagnetic fields of lowerfrequencies, from ELF to microwaves,suggests that innovating technologies maycreate concern, or even fear, among thepublic for hypothetical health risks.Social research has shown that worries arerelated to the perception of risks by thepublic more than to their actual existence.Risk perception depends on several factors,many of which are relevant forelectromagnetic fields. They include lackof familiarity with the agent, difficultyin understanding interaction mechanisms,and uncertainty in scientific knowledge.Lessons learnt from the past lead torecommend that specific research onbiological effects of terahertz radiationbe started from the very beginning of thedevelopment of technological applicationsand that a continuous and effectivedialogue be established between thescientific community and the public.  相似文献   

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Various proteins are known to exhibit one-dimensional Brownian motion along charged rodlike polymers, such as microtubules (MTs), actin, and DNA. The electrostatic interaction between the proteins and the rodlike polymers appears to be crucial for one-dimensional Brownian motion, although the underlying mechanism has not been fully clarified. We examined the interactions of positively-charged nanoparticles composed of polyacrylamide gels with MTs. These hydrophilic nanoparticles bound to MTs and displayed one-dimensional Brownian motion in a charge-dependent manner, which indicates that nonspecific electrostatic interaction is sufficient for one-dimensional Brownian motion. The diffusion coefficient decreased exponentially with an increasing particle charge (with the exponent being 0.10 kBT per charge), whereas the duration of the interaction increased exponentially (exponent of 0.22 kBT per charge). These results can be explained semiquantitatively if one assumes that a particle repeats a cycle of binding to and movement along an MT until it finally dissociates from the MT. During the movement, a particle is still electrostatically constrained in the potential valley surrounding the MT. This entire process can be described by a three-state model analogous to the Michaelis-Menten scheme, in which the two parameters of the equilibrium constant between binding and movement, and the rate of dissociation from the MT, are derived as a function of the particle charge density. This study highlights the possibility that the weak binding interactions between proteins and rodlike polymers, e.g., MTs, are mediated by a similar, nonspecific charge-dependent mechanism.  相似文献   

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Resistance or susceptibility of Red Kidney, Pinto and Small White beans (Phaseolus vulgaris) to the alpha, beta, and gamma strains of Colletotrichum lindemuthianum was either confirmed or established. These fungal strains secrete α-galactosidase, β-galactosidase and β-xylosidase when grown on cell walls isolated from the hypocotyls of any of the above bean varieties. These enzymes effectively degrade cell walls isolated from susceptible 5-day old hypocotyls but degrade only slightly the walls isolated from resistant 18-day old hypocotyls. The amounts of the β-galactosidase and β-xylosidase secreted by the 3 fungal strains are relatively low and are approximately equivalent. The secretion of these 2 enzymes is not dependent upon the bean variety from which the hypocotyl cell walls used as a carbon source were isolated. However, the fungal strains secrete greater amounts of α-galactosidase when grown on hypocotyl cell walls isolated from susceptible plants than when grown on walls from resistant plants. Virulent isolates of the fungus, when grown on hypocotyl cell walls isolated from a susceptible plant, secrete more α-galactosidase than do attenuated (avirulent) isolates of the same fungal strain grown under the same conditions. The α-galactosidase secreted by each of the fungal strains is capable of removing galactose from the hypocotyl cell walls of each bean variety tested. Galactose is removed from the cell walls of each variety at the same rate regardless of whether the cell walls were isolated from a susceptible or resistant plant.  相似文献   

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We analyzed the reports in which human brain electrical activity was compared between the presence and absence of radio-frequency and low-frequency electromagnetic fields (EMFs) from mobile phones, or between pre- and post-exposure to the EMFs. Of 55 reports, 37 claimed and 18 denied an EMF-induced effect on either the baseline electro encephalogram (EEG), or on cognitive processing of visual or auditory stimuli as reflected in changes in event-related potentials. The positive reports did not adequately consider the family-wise error rate, the presence of spike artifacts in the EEG, or the confounding role of the two different EMFs. The negative reports contained neither positive controls nor power analyses. Almost all reports were based on the incorrect assumption that the brain was in equilibrium with its surroundings. Overall, the doubt regarding the existence of reproducible mobile-phone EMFs on brain activity created by the reports appeared to legitimate the knowledge claims of the mobile-phone industry. However, it funded, partly or wholly, at least 87% of the reports. From an analysis of their cognitive framework, the common use of disclaimers, the absence of information concerning conflicts of interest, and the industry's donations to the principal EMF journal, we inferred that the doubt was manufactured by the industry. The crucial scientific question of the pathophysiology of mobile-phone EMFs as reflected in mea surements of brain electrical activity remains unanswered, and essentially unaddressed.  相似文献   

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We report our experience in the treatment of congenital pseudarthrosis with pulsing electromagnetic fields in a controlled study. Both the stimulated and control groups received the same surgical procedure: excision of the pseudarthrosis site, reduction and fixation by intramedullary nail. Stimulation with electromagnetic fields was begun within 3 days after surgery. The orthopaedic treatment was the same for all patients. The stimulation lasted up to 12 months. All patients were followed at least 24 months after the surgery. The data showed that the surgical approach in association with pulsing electromagnetic-field stimulation gave significantly better results than surgery alone.  相似文献   

15.
AimTo evaluate the prevalence of alcohol consumption among university students during late adolescence and young adulthood and to identify the associated factors.ResultsThe rates of prevalence of RC were lower, but not statistically significant, in women. The age-related changes in these rates were similar in both genders, and the prevalence of RC peaked at 20 years. By contrast, the prevalence of HED was significantly lower in women and peaked at 18 years in women and at 22 years in men. Multivariate models showed that early age of onset of alcohol use (OR = 10.6 and OR = 6.9 for women; OR = 8.3 and OR = 8.2 for men) and positive expectations about alcohol (OR = 7.8 and OR = 4.5 for women; OR = 3.6 and OR = 3.3 for men) were the most important risk factors for RC and HED. Living away from the family home was also a risk factor for both consumption patterns among women (OR = 3.16 and OR = 2.34), while a high maternal education level was a risk factor for RC among both genders (OR = 1.62 for women; OR = 2.49 for men).ConclusionsAlcohol consumption decreases significantly at the end of youth, with higher rates of prevalence and a later peak among men. Prevention strategies should focus on beliefs and expectations about alcohol and on delaying the age of onset. Women are at particular risk for these consumption patterns if they live away from their parents. Belonging to a high-income family is a strong risk factor for RC.  相似文献   

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The potential of clectromagnetic ficlds(EMFs)for discase treatment and health enhancement has been actively pursued over the recent decades.This review first provides a general introduction about natural EMFs and related biological effcts.Then the recent progress on the EMF treatment of some common diseases(such as cancer,diabetes,wound healing and neurological diseases,etc.)has been carefully reviewed and summarized.Yet,the blindness on the selection of therapeutic EMF parameters still hinders the broad application ofEMF therapy.Moreover,the unclear mechanism of EMF function and poor reproducibility of experimental rcsults also remain big challenges in the field of bioclectromagnetics.Bionics is a useful methodology that gains inspiration from nature to serve human life and industry.We have discussed the feasibility of applying bionic approach on the selection of the rapeutic EMFs,which is based on thefindings of natural EMFs.Finally,we advocate that the detailed information of EMFs and biological samples should be thoroughly reorded in future research and reported in publications.In addition,the publication of studies with negative results should also be allowed.  相似文献   

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The effect of pulsed electromagnetic field (PEMF) on bone healing is still uncertain and it has not been established as a standardized treatment. The aim of this systematic review and meta-analysis is to evaluate the effect of PEMF on bone healing in patients with fracture. We searched CNKI, Wan Fang, VIP, EMbase, PubMed, CENTRAL, Web of Science, Physiotherapy Evidence Database, and Open Grey websites for randomized controlled trials (published before July 2019 in English or Chinese) comparing any form of PEMF to sham. Reference lists were also searched. Related data were extracted by two investigators independently. The bias risk of the articles and the evidence strength of the outcomes were evaluated. Twenty-two studies were eligible and included in our analysis (n = 1,468 participants). The pooled results of 14 studies (n = 1,131 participants) demonstrated that healing rate in PEMF group was 79.7% (443/556), and that in the control group was 64.3% (370/575). PEMF increased healing rate (RR = 1.22; 95% confidence interval [CI] = 1.10–1.35; I2 = 48%) by the Mantel–Haenszel analysis, relieved pain (standardized mean difference (SMD) = −0.49; 95% CI = −0.88 to −0.10; I2 = 60%) by the inverse variance analysis, and accelerated healing time (SMD = −1.01; 95% CI = −2.01 to −0.00; I2 = 90%) by the inverse variance analysis. Moderate quality evidence suggested that PEMF increased healing rate and relieved pain of fracture, and very low-quality evidence showed that PEMF accelerated healing time. Larger and higher quality randomized controlled trials and pre-clinical studies of optimal frequency, amplitude, and duration parameters are needed. © 2020 Bioelectromagnetics Society.  相似文献   

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SYNOPSIS. In Tetrahymena thermophila subline B, a morphogenic alteration of the anterior end of cells of mating types III and VII results from a cellular interaction which precedes and is a prerequisite for pairing. Cell pairing begins 1 h after starved cells of complementary mating type are mixed. The 1 h-long lag period is characterized by an actinomycin D-sensitive inductive interaction in the first 30 min, followed by a maturation period. Tip transformation begins during the maturation period and continues after pairing. Scanning electron microscopy of deciliated cells reveals ridges which form a chevron meeting in a midline seam between the oral apparatus and the anterior tip. During transformation, the seam broadens until the ridged surface is completely smooth. Melding of the ridges also occurs at the tip of the cell resulting in its blunted appearance. Cells of complementary mating types join in the region of this modified surface, which eventually becomes a specialized cell junction perforated by cytoplasmic bridges. Thus, pursuant to an inductive interaction the structure of the tip of cells is modified in anticipation of the pairing event. Rate of cell pairing might be limited by rate of tip transformation.  相似文献   

19.
Phagocytosis is a process in which a cell engulfs material (entire cell, parts of a cell, debris, etc.) in its surrounding extracellular environment and subsequently digests this material, commonly through lysosomal degradation. Microglia are the resident immune cells of the central nervous system (CNS) whose phagocytic function has been described in a broad range of conditions from neurodegenerative disease (e.g., beta-amyloid clearance in Alzheimer’s disease) to development of the healthy brain (e.g., synaptic pruning)1-6. The following protocol is an engulfment assay developed to visualize and quantify microglia-mediated engulfment of presynaptic inputs in the developing mouse retinogeniculate system7. While this assay was used to assess microglia function in this particular context, a similar approach may be used to assess other phagocytes throughout the brain (e.g., astrocytes) and the rest of the body (e.g., peripheral macrophages) as well as other contexts in which synaptic remodeling occurs (e.g. ,brain injury/disease).  相似文献   

20.
荧光共振能量转移(fluorescenceresonanceenergytransfer,FRET),是指能量从一种受激发的荧光基团(fluorophore)以非辐射的方式转移到另一种荧光基团的物理现象.FRET的能量转移效率是两个荧光基团间距离的函数,并对此距离十分敏感,它的有效响应距离一般在1~10nm之间,因而可被用于测定原子间及分子间的距离.这一特点使FRET技术在大分子构象变化、大分子之间相互作用、细胞信号通路等研究中发挥重要作用,成为生物医学研究中的重要方法.但细胞内的生物学过程常常涉及多于两个的大分子间相互作用,二色荧光基团的FRET技术不能满足这种生物学研究的需求.最近,两个研究小组在这方面取得突破,建立了分别基于共聚焦显微镜和流式细胞仪的三色荧光级联FRET技术.这一技术的出现将会极大地促进生物学及相关研究领域的发展.  相似文献   

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