网范文：“Evidence of Safety of Radiofrequecy Radiation” 当前的科学证据表明,暴露在射频场,诸如移动电话及其基站,不太可能诱发或促进癌症。在这篇范文中，英语论文题目，对于动物的几项探讨，英语论文题目，暴露在射频场没有发现射频引起或促进脑癌。也没有企业人员来自电磁场，导致致癌风险提高。一项探讨表明,普通手机使用也没有增加神经胶质瘤的风险,即使对模拟或数字手机分别进行了略论。
人类神经胶质瘤细胞的体外探讨,测量各种磷酸化蛋白质,没有增加肿瘤发生的手机辐射的作用。然而,一些探讨没有显示任何颅内恶性肿瘤的情况。下面的范文进行详述。
Current scientific evidence indicates that exposure to RF fields, such as those emitted by mobile phones and their base stations, is unlikely to induce or promote cancers. Several studies of animals exposed to RF fields similar to those emitted by mobile phones found no evidence that RF causes or promotes brain cancer. The United Kingdom NRPB Advisory Group on Non-ionising Radiation concluded that there is no firm quantitative evidence of a carcinogenic hazard from electromagnetic field exposures for the general public and workers in the electrical, electronics, and telecommunications industries.
A study showed that there was no increased glioma risk with regular mobile phone use, even when analog or digital phones were analyzed separately. However, ipsilateral tumor risk was borderline for usage ≥ 10 years, while risk for contralateral usage was not significant.[27] In-vitro studies of human glioma cells (MO54), measuring phosphorylation of various heatshock proteins, showed no increased tumorigenic effects of mobile phone radiation.[28] Several studies, however, have not shown any association between intracranial malignancies and mobile telephone usage. Some of these studies have included exposures of >10 years, exposure from cordless phone base-units, or even predominant unilateral use.[29-33] Two time-trend analyses have been published highlighting the change in incidence of various tumors since the introduction of mobile phone technology.
Both showed no significant rise in the incidence of intracranial malignancies despite the exponential growth of the mobile telephone industries.[34,35] Studies on other cancers[36] found no association between mobile phone usage and testicular cancers (seminoma and non-seminoma tumors). On study of lifetime exposures to mobile phone radiation as 100 hours and found no associations, for any of the groups, with incidence of NHL.[37] A study of malignant parotid tumors by[38] showed no association with mobile phone exposure, even when exposures exceeded 10 years.
A large-scale in vitro study was conducted focusing on lowlevel radiofrequency (RF) fields from mobile radio base stations employing the International Mobile Telecommunication 2017 (IMT-2017) cellular system to test the hypothesis that modulated RF fields induce apoptosis or other cellular stress response that activate p53 or the p53-signaling pathway.[39] Human glioblastoma A172 cells were exposed to W-CDMA radiation at SARs of 80, 250, and 800 mW/kg, and CW radiation at 80 mW/kg for 24 or 48 h. Under the RF field exposure conditions described above, no significant differences in the percentage of apoptotic cells were observed between the test groups exposed to RF signals and the sham-exposed negative controls, as evaluated by the Annexin V affinity assay. No significant differences in expression levels of phosphorylated p53 at serine 15 or total p53 were observed between the test groups and the negative controls by the bead-based multiplex assay.
Moreover, microarray hybridization and real-time RT-PCR analysis showed no noticeable differences in gene expression of the subsequent downstream targets of p53 signaling involved in apoptosis between the test groups and the negative controls. This results confirm that exposure to low-level RF signals up to 800 mW/kg does not induce p53-dependent apoptosis, DNA damage, or other stress response in human cells. Another study was conducted to demonstrate the effect of the RF on the molecular level that is DNA structural configuration. In this exposed human glioblastoma A172 cells and normal human IMR-90 fibroblasts from fetal lungs to mobile communication frequency radiation to investigate whether such exposure produced DNA strand breaks in cell culture. Under the same RF field exposure conditions, no significant differences in the DNA strand breaks were observed between the test groups exposed to W-CDMA or CW radiation and the 3 sham exposed negative controls, as evaluated immediately after the exposure periods by alkaline comet assays.[40]
There have been earlier studies to investigate cytogenetic damage in human blood lymphocytes after exposure to 2450 MHz RF radiation conducted[41], immediately after the RF-radiation exposure; the lymphocytes were cultured to determine the incidence of chromosomal aberrations and micronuclei. The incidences of chromosomal damage, exchange aberrations and acentric fragments in the lymphocytes exposed to RF radiation (continuous or intermittent) were not significantly different from those in sham-exposed cells. Comparison of micronuclei in the lymphocytes exposed to RF radiation was not significantly different from that in the sham-exposed cells. When the continuous and intermittent exposures were compared, there were no significant differences in any of the cytogenetic parameters investigated.
Another study conducted[42] found no chromosomal aberrations in antenna maintenance workers who had been exposed to various RF fields at least one hour each day for more than a year. Studies on bacteria, plant and animal cells exposed in vitro, where thermal effects can be directly observed and/or controlled, have failed to reveal direct evidence of DNA damage or repair, even at power densities up to 100 W/m2 and SARs up to 20 W/kg.[43-49] Same results were obtained[50] that there was no cell transformation in similar experiments involving 836.55 MHz radiation. Even in the presence of cancer promoting agents, it was found that no epigenetic influence of RF radiation on the production of chromosomal aberrations by mitomycin-C or another mitogen, adriamycin.[51,52] A number of other studies have failed to demonstrate enhancement of the mutagenic action of chemical carcinogens.[53-55] It was ed that the chronic exposure to 2.45 GHz RF radiation had no effect on the incidence or size of colon cancers induced in mice by dimethylhydrazine. [56]
No effect of exposure at the Japanese cellular phone frequency of 1.439 GHz for six weeks using the standard medium-term rat liver tumour promotion model, in which neoplastic foci are induced in the liver by diethylnitrosamine and partial hepatectomy were found.[57] Similar results for 929.2 MHz radiation had been ed previously.[58] Case control study carried out in US[59], involving 782 cases of intracranial tumours of the nervous system identified between 1994 and 1998, and 799 hospital based controls. Use of mobile phones was by self of type of mobile phone, start and end of time of use, duration of “regular” use, frequency of use, and hand used to hold the phone. Results when adjusted for socioeconomic variables and history of medical exposure to ionizing radiation showed no association between ever use or regular use of a cell phone and risk of any of the types of brain tumour (OR = 1.0 overall; 0.7 for high exposed group); nor was a higher risk identified for those with longer use, increasing duration or frequency or total cumulative use of cellular phones.
No association was seen between laterality of tumor and laterality of phone use. A study of nearly 200,000 Motorola employees representing 2.7 million personyears of possible exposure between 1976 and 1996 was done. The investigators concluded that their findings "do not support an association between occupational RF exposure and brain cancers or lymphoma/leukemia. Also there are reviews conducted by number of authorities of the potential health risks associated with exposure to RF fields.[60] The advice of the U.S. Health Physics Society (a professional society of specialists in radiation safety) is that there is no reason to believe that cellular base station towers could constitute a potential health hazard to nearby residents or students. [61] Several groups in Great Britain have evaluated potential health effects of RF. The Advisory Group on Non-Ionizing Radiation (2017) updated the year 2017 of the Independent Expert Group on Mobile Phones (2017) and concluded that “expos res due to living near to base stations are extremely low, and the overall evidence indicates that they are unlikely to pose a risk to health.[62] Even in mice exposed to 800 MHz RF radiation for 2 h/day, 5 days/week, for 35 weeks. When checked for end points included erythrocyte and leukocyte count, hemoglobin level, hematocrit, activity level, body weight and life span. No significant differences between the RF-radiation-exposed and sham-exposed groups were seen for any of these measures. [63] The mean life span of the exposed group (664 days) was slightly but not significantly longer than that of the sham-exposed group (645 days).
Conclusions
The epidemiological evidence currently available does not suggest that RF exposure causes cancer. This conclusion is compatible with the balance of biological evidence, which suggests that RF fields below guidelines do not cause mutation, or initiate or promote tumour formation. However, mobile phones have not been in use for long enough to allow comprehensive epidemiological assessment of their impact on health, and we cannot, at this stage, exclude the possibility of some association between mobile phone technology and cancer. In view of widespread concern about this issue, continued research is essential. There is a pressing need for case–control studies to examine whether leukaemia and cancers of the brain, acoustic nerve and salivary gland are caused by mobile phone use. We propose that large case–control studies of brain cancer, acoustic neuroma, salivary gland cancer, and leukaemia should be funded.
We further recommend that this programme be financed by the mobile phone companies and the public sector (industry departments, health departments and the research councils) The baffling evidence swaying in either direction of the prevailing controversy regarding relationship between EMR and mobile phone users is quite remarkable. With increasing number of users of this facility which is expected to increase 1.5 times in the next couple of years, the urgency to solve the puzzle should take a priority. It has been observed that the major fear lies with the populations residing in close proximity to the transmission base stations or EM towers which emit EMR continuously to power levels from a few watts to 100 watts depending on the “cell size” or area of coverage. If there are any risks, these are maximum for those living in the vicinity of larger cell size base stations.
The need to reconsider international guidelines developed by International Commission on Non-Ionizing Radiation Protection (ICNIRP) or by International Agency for Research on Cancer (IARC) becomes relevant on the basis of phenomenal increase in the number of service providers, mobile phone users, installations of new base stations near dense populations as also the fact that the population at risk has increased due to ever escalating population in almost every country. In India and other countries where this facility is accessed by significantly higher population, there is a need to raise the level of understanding about this technology and EMR, to reduce any real or perceived threats. More research is required at the cellular and molecular level to critically and accurately assess the effects of different levels and duration of exposure of EMR. Based on such data and with an effective coordination between scientists, health authorities, industry and the public, revised public health information on this subject needs to be evolved. The time to clear the mist over this cancer controversy couldn’t be any better than now when some of the service providers may be willing to join hands with the scientific community to observe safety measures or to reassure the user. The curiosity over the controversy may generate enough stress. It may not be the EMR but the stress related to the mys- tery that may eventually kill. After all, don’t they say, curiosity kills the cat!()
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