2例严重的~(60)Co放射事故受照人员的牙齿剂量估算

目的用电子自旋共振方法对山东事故中两例受照人员的3颗牙齿进行剂量估算。方法将受照人员的牙齿经过处理后得到牙釉质样品,进行ESR信号测量,将样品ESR信号的相对强度代入本实验室建立的牙釉质剂量响应曲线后,得到的3颗牙齿的吸收剂量。结果两例受照人员牙釉质ESR吸收剂量剂量分别为:受照人A的牙齿剂量为26.1~29.4Gy;受照人B的两颗牙齿剂量分别为14.9~18.3Gy,15.2~18.5Gy。结论两例受照人员牙釉质ESR剂量测量方法为大剂量照射事故剂量估算提供了一种重要的依据。     

辐照食品的电子自旋共振波谱(ESR)研究

目的 研究市售辐照食品的电子自旋共振波谱(ESR),探索有效的辐照食品卫生监督方法。方法 对市售食品采样,经3~20 kGy剂量范围进行辐照处理,测定其电子自旋共振波谱,研究辐照后产生的自由基浓度与辐照剂量的关系。结果 ESR信号强度随剂量增加而增加,样品在室温下保存98 d,ESR信号强度逐渐减弱,但信号不会消失。结论 辐照食品的剂量与ESR信号关系清晰,可作为建立ESR方法检测辐照食品的方法。     

牙釉质EPR剂量学方法应用于医用诊断X射线工作者剂量重建的方法研究

目的 建立牙釉质EPR剂量学方法应用于医用诊断X射线工作者剂量重建的方法。方法 利用电离辐射在牙釉质中诱导产生的CO₂^-自由基浓度与牙釉质剂量成正比的特点,通过EPR方法测量电离辐射在牙釉质中诱导产生的自由基浓度,得出牙釉质吸收剂量信息,重建医用诊断X射线工作者的受照剂量。结果 重建了1985年之前参加工作的14名医用诊断X射线工作者的牙釉质剂量,剂量范围为89~870mGy。结论 提供了一种医用诊断X射线工作者剂量重建的直接测量方法。     

60 Co γ射线照射离体人血建立染色体畸变的剂量-效应曲线

目的建立^60Coγ射线照射离体人血诱发染色体畸变的剂量一效应曲线。方法采集健康成人外周静脉血，^60Coγ射线照射，照射吸收剂量为0～5．0Gy，剂量率为0．38Gy／min。采用开始加入秋水仙碱法进行细胞培养48h。制片后观察淋巴细胞中染色体型非稳定性畸变，包括双着丝粒体、着丝粒环、无着丝粒断片等。用双着丝粒体加着丝粒环对剂量进行曲线拟合。结果离体外周血经^60Coγ射线照射后，在0～5.0Gy范围内“双 环”率与剂量在不同剂量范围建立的回归方程为：0～0．5Gy，y=0.00217 0.08283D^2；0～1．0Gy，y=0.00146 0．09310D^2；0～5，0Gy，y=0．04851D^2.18601；0.5-5．0Gy，y=0.04848D^2.18645。结论成功建立了^60Coγ射线照射离体人外周血诱发染色体畸变剂量效应曲线。     

MOSFET用作临床X射线剂量测量的研究

目的利用场效应晶体管对X射线的敏感性,探讨制作出符合临床需要、实用的X射线计量探测器的可行性。方法①确定合适的场效应晶体管工作参数,即确定工作电压VDS以及漏极电阻DR,并测量在X射线照射场效应晶体管时,漏极电阻DR上的电压降VDR,以确定场效应晶体管对X射线照射是否敏感。②任选市售不同型号的场效应晶体管若干,并在临床的标准条件下对这些场效应晶体管作X射线照射,通过测定VDR值,以确定场效应管对X射线照射反应的普遍性。③使用电离室（临床标准配置）对X射线的剂量作标定,并对处于相同X射线照射下场效应晶体管的VDR值作比对测量,以确定VDR值与X射线剂量之间的函数关系。④大剂量X射线照射试验用场效应晶体管,通过观察其对大剂量射线轰击的耐受性,以确定其作为传感器应当具有的可靠性。结果市售场效应晶体管对X射线照射的反应具有普遍性;其输出信号与X射线剂量之间具有很好的线性关系;试验用场效应管能够经受大剂量1000cGy的15MV高能X射线轰击。结论经过挑选的市售场效应晶体管完全能适用作临床上检测X射线的相对剂量。     

四种微核测定方法在剂量效应关系中的应用

研究了用明胶法、甲基纤维素法(MC法)、培养法和松胞素-B法(CB法)等4种方法在14 MeV中子、⁶⁰Co γ射线和X射线等不同剂量照射离体人血诱发淋巴细胞微核率与照射剂量关系。结果显示,用不同方法、不同射线及其作用的不同时间,所诱发的微核率不同。微核率与受照剂量呈线性关系,培养法和CB法的微核与剂量的关系为密切相关,可作为生物剂量计。还对4种方法的优缺点、灵敏度以及微核出现的机理等进行了讨论。     

染色体畸变分析的用途及价值怎样?

染色体畸变分析在急性大剂量放射线照射的检测上能非常准确地反应机体照射的剂量,可预示机体受射线损害的程度等。因为机体受射线照射后,体细胞染色体畸变的发生率与照射剂量的大小呈恒定的线性关系,所以染色体畸变分析对射线照射检测来说,誉有“生物剂量仪”之称。多用于各种类型的X或γ射线     

X射线对体外培养乳鼠心肌细胞损伤的初步实验研究

目的：初步探讨一定剂量的X射线对体外培养乳鼠心肌细胞的损伤。方法：全自动生化分析仪定量测定不同剂量X射线照射后第24小时心肌细胞培养基乳酸脱氢酶（1actate dehydrogenase,LDH）的含量;激光扫描共聚焦显微镜观察心肌细胞经40GyX射线照射后第24h的形态学改变。结果：心肌细胞有较高的辐射抗性,在0Gy～30Gy的放射剂量下心肌细胞培养基乳酸脱氢酶的含量变化不是很明显（P〉0．05）;当放射剂量≥40Gy时培养基乳酸脱氢酶的含量显著升高（P〈0．05）;激光扫描共聚焦显微镜观察到经40GyX射线照射后第24h的典型的心肌细胞形态学改变。结论：一定剂量的X射线对心肌细胞有直接损伤作用。     

60Co γ射线照射对体外培养的心肌细胞活性及凋亡的影响

目的研究60Co γ射线照射对体外培养的心肌细胞活性及凋亡的影响。方法体外培养新生大鼠心肌细胞,分为对照组和照射组,照射组细胞分别用60Co γ射线5Gy、10Gy、20Gy单剂量照射心肌细胞,照射后48h检测细胞培养上清中乳酸脱氢酶(LDH)浓度,流式细胞仪检测60Coγ射线照射对体外培养的心肌细胞凋亡的影响,照射后48h及120h用结晶紫试验及MTT试验检测照射后心肌细胞活性变化,结果照射组LDH浓度明显高于未照射组,且随照射剂量增加而升高。照射后48h凋亡细胞较对照组升高,凋亡细胞比例与照射剂量呈正相关。结晶紫试验及MTT试验均提示照射后48h照射组心肌细胞活细胞活性与对照组无明显差异,照射后120h照射组活细胞活性明显低于对照组,且与照射剂量相关。结论60Co γ射线单剂量照射可直接损伤心肌细胞,降低体外培养的心肌细胞活性,促进心肌细胞凋亡。     

X-射线衍射法测定空气中温石棉的方法

在美国国家职业安全与健康学会“石棉温石棉的X－射线衍射分析法”的理论基础，建立适合我国国情的温石棉的X－射线衍射分析法。采用在X－射线衍仪样品盘上一次性加薄银片，仍然使用美国方法的银滤膜校正公式的方法，来克服质量吸收的影响。方法的检测下限是每张微孔滤膜上0.06mg温石棉。粉尘量2.2mg以下，温石棉与其衍射强度呈线性关系。回收率为92.9%-104.3%,CV=3.8%。     

Calcium intake in the elderly: validation of a dietary questionnaire

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r = 0.76 and r = 0.69, while that for repeatability was r = 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.     

Self-reported health problems among Swedish miners one year after unemployment

Unemployment is considered to be a public health concern sincedeterioration in the health of the unemployed is often anticipated.However, for some groups, such as miners, unemployment mightimprove health due to a cessation of potentially harmful occupationalexposures. This study evaluates the health of 79 miners in oneSwedish iron-ore mine, and 226 age-matched controls from thegeneral population, during one year after the closure of themine. The participants received a questionnaire regarding medicalhistory and subjective symptoms at the beginning of the studyperiod, and after one year. Statistically significant negativeeffects on self-reported health attributable to unemploymentwere not found, although neuropsychiatric symptoms were morecommon among the unemployed miners. The miners reported a statisticallysignificant improvement in grip force (p=0.031). They had asignificantly higher prevalence of symptoms associated withmining related exposures when compared with the population controls;pain in the upper extremities [relative risk (RR)=2.27, 95%confidence interval (Cl)=1.44–3.59), back pain (RR=1.84;Cl=1.237–2.75), vasospastic disease of the fingers (RR=2.05;Cl=1.18–3.57) and obstructive respiratory symptoms (attacksof dyspnea and wheezing: RR=3.67; Cl=1.167–11.6).     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.     

Occupational health hazards in mining: an overview

This review article outlines the physical, chemical, biological, ergonomic and psychosocial occupational health hazards of mining and associated metallurgical processes. Mining remains an important industrial sector in many parts of the world and although substantial progress has been made in the control of occupational health hazards, there remains room for further risk reduction. This applies particularly to traumatic injury hazards, ergonomic hazards and noise. Vigilance is also required to ensure exposures to coal dust and crystalline silica remain effectively controlled.     

Manufacture and use of nanomaterials: current status in the UK and global trends

This paper provides an overview of the production and use of nanomaterials (NMs), particularly in the UK. Currently, relatively few companies in the UK are identifiable as NM manufacturers, the main emphasis being the bulk markets in metals and metal oxides, and some niche markets such as carbon nanotubes and quantum dots. NM manufacturing in the UK does not reflect the global emphasis on fullerenes, nanotubes and fibres. Some assumptions have been made about the types of NM that are likely to be imported into the UK, which currently include fullerenes, modified fullerenes and other carbon-based NMs including nanotubes. Many university departments, spin-offs and private companies have developed processes for the manufacture of NMs but may only be producing small quantities for research and development (R&D) purposes. However, some have the potential to scale up to produce large quantities. The nanotechnology industry in the UK has strong R&D backup from universities and related institutions. This review has covered R&D trends at such institutions, and appropriate information has been added to a searchable database. While several companies are including NMs in their products, only a few (e.g. manufacturers of paints, coatings, cosmetics, catalysts, polymer composites) are using nanoparticles (NPs) in any significant quantities. However, this situation is likely to change rapidly. There is a need to collect more information about exposure to NPs in both manufacturing and user scenarios. As the market grows, and as manufacturers switch from the micro- to the nanoscale, the potential for exposure will increase. More research is required to quantify any risks to workers and consumers.     

深圳公立医院管理体制改革制度设计

深圳公立医院管理体制改革实行政事分开、管办分开,在理事会架构下按法定机构模式组建市医管中心,落实公立医院运营管理自主权.作者从当前公立医院管理体制的弊端入手,介绍了深圳市进行公立医院管理体制改革的基本思路及改革方案设计的主要举措,深入剖析了的改革方案的特点,并对改革效果进行了预测.     

Effects of nitrogen dioxide on red blood cells of rats: Changes in components of red cell membranes during in vivo exposure to NO2

Red cell membranes, prepared from red blood cells of rats exposed to 4, 10, or 20 ppm nitrogen dioxide (NO₂) for 1 to 10 days, were examined for evidence of changes in membrane components. Appreciable changes were not found in contents of phospholipid and cholesterol during exposure to 10 ppm NO₂. By contrast, protein content altered with the time of exposure. Moreover, changes in protein composition were observed by employing sodium dodecyl sulfate — polyacrylamide gel electrophoresis. Twenty-four-hour exposure to NO₂ at the concentration above 10 ppm resulted in a marked increase in the percentage of lysophosphatidylethanolamine (LysoPE) to the total phospholipids. The prolonged exposure to 10 ppm NO₂ gave rise to a further increase in LysoPE, whereas the percentage of phosphatidylethanolamine (PE) showed a gradual decrease. A 1-day exposure to 4.0 ppm NO₂ also caused an increase in sialic acid content and decreases in those of PE and hexose. In addition to contents of these components the percentage of LysoPE increased 5 days after exposure and the elevated values were maintained up to the end of exposure period. These results demonstrate that red blood cells in circulation exhibit different membrane properties in terms of lipid and carbohydrate composition during 10 days of exposure to 4.0 ppm NO₂.     

Investigating clusters in the workplace and beyond

Clusters of disease are common and occur in the workplace and in the general community. They often arouse considerable concern among the population. Investigations have sometimes lead to exciting new knowledge, but in general the investigation of clusters is difficult and often unrewarding, especially for community clusters. In the workplace, investigations are more likely to find associations and even new causes, but still many clusters remain enigmatic. Despite this, there are many reasons for investigating clusters, including allaying community concern and identifying uncontrolled exposures. A structure for investigating clusters in the workplace is suggested.