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正Incomplete combustion of bituminous coal will produce a large number of coke oven emissions(COEs). Polycyclic aromatic hydrocarbons(PAHs)account for the largest proportion of these COEs.PAHs enter the human body mainly through the respiratory tract, digestive tract, and skin~([1]),becoming hydroxyl PAHs(OH-PAHs) following their metabolism by the human body and are ultimately excreted mainly in urine. OH-PAHs in urine can effectively reflect the internal exposure to PAHs and  相似文献   
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目的 拟利用241Am-Be中子源设计并建立一套中子辐射照射实验装置。方法 采用蒙特卡洛(Monte Carlo)方法,模拟计算装置内外中子能谱和γ能谱空间分布数据,研究中子注量等随空间分布的变化规律;初步建立镅铍中子装置的数学模型,采用影锥法、平方反比律验证等数据分析方法,对中子输运过程进行研究。结果 模拟获得测量点处归一化快中子注量有效剂量约为72.9 pSv/n,光子约为3.04 pSv/γ,光子注量有效剂量与中子注量有效剂量的比值约为4.17%。结论 利用蒙特卡洛方法,构建了镅铍中子源标准装置模型,优化了影锥设计,初步讨论了将影锥转换法用于建立中子源辐射照射装置的可行性。  相似文献   
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A hydroxypridinone derivative of desferrioxamine (Na-DFO-HOPO), a dihydroxamic derivative of diethylenetriaminepenta-acetic acid (ZnNa-DTPA-DX), and DTPA (CaNa3- and ZnNa3-DTPA) were tested at dosages of 30 μmol kg?1 for their ability to remove 238Pu or 241Am from rats after their intravenous injection as citrate or inhalation as nitrate. The most effective treatment regimen for injected Pu was the repeated administration of DFO-HOPO; by 7 days the body content was reduced to 8% of that in untreated animals. Repeated dosages of 3 μmol kg?1 DFO-HOPO were as effective as those of 30 μmol kg?1 DTPA. After inhalation of Pu nitrate, repeated treatment with DTPA, DTPA-DX or DFO-HOPO reduced the body content by 7 days to, respectively, 10, 15 and 31% of those in untreated animals. After inhalation of Am, DTPA-DX and DTPA were equally effective, the body contents being reduced to 7% of control values with repeated treatment. Injection of DFO-HOPO was ineffective for enhancing the elimination of inhaled or injected Am. The results confirm the strategy of examining the use of siderophore analogues for the decorporation of Pu or Am. However, at present DTPA should remain the agent of choice, particularly after inhalation.  相似文献   
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The incorporation of 210Pb into resting and growing hair has been studied in rabbits. It was found that in the telogen (resting) hair the concentrations of 210Pb were from 7 to 137 times lower than in the anagen (growing) hair. The concentrations in the anagen hair were dependent both on the total dose of injected 210Pb and on the mode of dose fractionation.  相似文献   
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Radiation carcinogenesis is generally considered to be the most important detrimental effect of exposure to ionizing radiation. The collective effective dose-equivalent values due to medical procedures amount to values between 10 and 20 per cent of the doses received from natural radiation. Risk factors have been derived up to the present from three large epidemiological studies, notably atomic bomb survivors, spondylitis patients and female patients treated for cancer of the cervix. The assessment of the absorbed doses received by the inhabitants of Hiroshima and Nagasaki has received continuous attention and the latest estimates are summarized. On the basis of original radiotherapy records the absorbed doses in organs adjacent to the primary treatment field can be derived from computerized dosimetry and this source of information should be further exploited. European co-operation has been established to investigate dosimetric problems for medical applications and radiation protection. The risk factors obtained up to the present are derived at relatively high dose levels (in excess of 0·3 Gy). The uncertainties in the extrapolation of these values to the area of low doses administered at low dose rates are discussed.  相似文献   
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IntroductionThe idea of radiographer image interpretation has not been fully explored in Fiji despite the great shortage of radiologists in the country. This is a feasibility study of radiographer image interpretation aimed at assessing the accuracy of radiographers in interpreting adult chest X-ray images at the Colonial War Memorial Hospital (CWMH) in Fiji.MethodsForty PA chest X-ray images were interpreted in terms of correctly commenting on the presence/ absence of pathology, the name of the pathology, and the location of the pathology on the data sheets by the CWMH diagnostic radiographers (n = 14). The radiographers were grouped according to their years of work experience (≤ 5 vs > 5) and the Mann Whitney U test on a two-tailed p-value of 0.05 was used to compare this grouping.ResultsThe data analysis was conducted using the Statistical Package for Social Sciences (SPSS) v.25 and Microsoft Excel. The diagnostic performance of all radiographers in terms of triaging normal and abnormal in the images shows sensitivity ranging from 71.4 to 100%, with specificity ranging from 47.4 to 100%. The mean sensitivity, specificity, and the overall accuracy of radiographers in triaging normal and abnormal on the images were 89.5%, 72.9%, and 81.6%, respectively. The mean accuracy in naming the pathology was 33.6% and the location sensitivity was 45.7%. There was no statistically significant difference in results between the radiographers’ years of experience.ConclusionWithout any formal qualification, training, and practice, the current results suggest that the cohort of radiographers can perform normal/abnormal triage of CXRs within a test setting. With a significant reduction in the radiographers’ accuracy in terms of naming and locating the abnormality, the study results do not support image interpretation by the radiographers at this stage.Implications for practiceThis feasibility study provides baseline information about the accuracy of image interpretation by diagnostic radiographers at CWMH and provides a platform for further research in image interpretation in Fiji.  相似文献   
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