火焰原子吸收法测定滤膜中镍的不确定度评估

目的:给出火焰原子吸收分光光度法测定滤膜中镍的测量不确定度。方法:不确定度的主要来源为标准物质的不确定度,标准曲线的不确定度,以及测量重复性引起的不确定度,计算出各种不确定度分量并将其合成,以计算出滤膜中镍测量结果的不确定度。结果:按数学模型计算滤膜中镍的浓度为17.21μg/张,扩展不确定度为0.55μg/张,结果表达为17.21±0.55μg/张。结论:该方法适用于火焰原子吸收法测定滤膜中镍的不确定度评定。     

氢化物原子吸收光谱法测定豆奶中砷及不确定度评定

[目的]用氢化物原子吸收光谱法测定豆奶中砷含量及不确定度评定。[方法]样品经微波消解,用流动注射氢化物发生器及原子吸收分光光度仪检测,应用检测不确定度评定方法对测量结果进行不确定度分析与评定。[结果]该检测方法线性良好,相关系数r=0.9996,相对标准偏差为2.46%～2.83%,加标回收率为98.1%～99.2%,不确定度报告为(0.09±0.01)mg/kg取k=2。[结论]本方法可用于豆奶中砷含量的测定,不确定度评定合理。     

石墨炉原子吸收法测定食品中的锡

[目的]介绍测定食品中锡含量的石墨炉原子吸收方法。[方法]以微波消化和干法灰化为前处理，并以硝酸钯和硝酸镁为改进剂，最终采用石墨炉原子吸收方法进行锡的测定。[结果]实验能达到的最低检测限为0．053ng(湿法前处理)和0．023ng(干法前处理)，精密度为5．2％～8．5％，回收率为85％～108％，溶液中测量不确定度约为10μg／L。[结论]该检测方法简便、准确，检测灵敏度和精密度均良好。     

石墨炉原子吸收法直接测定血铅及其不确定度分析

[目的]建立一种石墨炉原子吸收光谱法直接测定血铅的方法,并对其不确定度进行分析.[方法]血样用0.15%(V/V)硝酸溶液稀释后,直接用石墨炉原子吸收法测定.并依据JJF1059-1999,对各不确定度分量进行分析评定.[结果]石墨炉原子吸收法测定血铅的灰化温度为500℃.标准曲线的线性范围为0-100 μg/L,方法的检出限为3.2μg/L,测定样品的相对标准偏差在2.1%～4.9%之间,冻干牛血标准物质GBW09139e的测定值与标准值的相对误差为1.7%.对于血铅含量为153.6 μg/L的冻干牛血质控样,其扩展不确定度为6.2 μg/L(k=2).[结论]该方法操作简便、快速、准确,符合生物材料中有害物质测定规范要求,可用于血铅的测定.     

石墨炉原子吸收法测定面粉中铅的不确定度评定

[目的]根据国家计量技术规范JJF 1135-2005<化学分析测量不确定度评定>的要求,以石墨炉原子吸收法测定面粉中铅为例对测定结果的不确定度进行评定. [方法]对不确定度的主要来源包括称量的不确定度、标准物质的不确定度、体积的不确定度、标准曲线的不确定度及测量重复性引起的不确定度进行分析,并按数学模型计算出各不确定度分量、合成标准不确定度和扩展不确定度.[结果]得到石墨炉原子吸收法测定面粉中铅的不确定度,当面粉中铅含量为0.122 mg/kg时,扩展不确定度为0.020 mg/kg,结果表达为(0.122±0.020)mg/kg.[结论]正确选择前处理方法和熟练掌握前处理方法极其重要.定容体积、样品称量产生的不确定度非常小,对测量结果影响不大.     

食用包装用聚乙烯树脂卫生标准中干燥失重测定的不确定度分析

[目的]对食用包装用聚乙烯树脂干燥失重测定进行评定,找出影响不确定度的因素,给出不确定度。[方法]依据JJF 1059-1999不确定度评定与表示,建立数学模型,得出食用包装用聚乙烯树脂干燥失重测定的合成不确定度和扩展不确定度。[结果]包装用聚乙烯树脂干燥失重测定的合成不确定度为0.00076 g/100 g,扩展不确定度为0.0015 g/100 g。[结论]测量不确定度分析,能有效掌握测定结果的可信程度和准确性,保证检测结果的质量。     

原子吸收分光光度法测定水中镍含量的不确定度评定

目的 评定用无火焰原子吸收分光光度法测定水中镍含量的不确定度.方法 按GB/T 5750.6-2006《生活饮用水标准检验方法:金属指标》中无火焰原子吸收分光光度法测定水中镍.结果 测定饮用水中镍含量为20.5 μg/L,不确定度为0.6 μg/L(k =2),其中标准溶液配制、样品重复性测定是主要的不确度来源.结论 该评定思路清晰,主要对标准溶液、工作曲线、样品重复性测定、仪器引起的相对标准不确定度进行评定,在实际工作中有较强实用性.     

硝酸-过氧化氢脱蛋白-石墨炉原子吸收法测定全血中铅

[目的]建立一种新的血铅石墨炉原子吸收快速测定法. [方法]采用含40mL/L硝酸与6mL/L过氧化氢的混合提取液,离心分离脱去全血中的蛋白,以磷酸二氢铵+硝酸镁为基体改进剂,石墨炉原子吸收光谱法直接上机测定. [结果]该方法的线性范围为10～400μg/L,最低检出限为4μg/L,加标回收率为87.8％～115.3％,相对标准偏差(RSD)为3.6％～8.6％. [结论]该新的血铅石墨炉原子吸收快速测定方法已成功应用于全血样品的铅测定,结果令人满意.     

实验室间比对样品滤膜中镍含量测定的不确定度评定

目的建立火焰原子吸收光谱法测定工作场所空气中镍含量的不确定度评定方法,从而找出影响测定结果的因素。方法依据GBZ/T 160.16-2004《工作场所空气有毒物质测定镍及其化合物》和JJF 1059-2012《测量不确定度评定与表示》标准分析测定过程中不确定度来源。结果火焰原子吸收光谱法测定滤膜中镍含量,当k=2时,U=0.98μg/张。结论运用该不确定度评定方法对测定过程中关键环节的识别,更有效地提高检测工作的质量。本次实验室间比对样品测定的不确定度主要来源是拟合校准曲线和标准溶液配制所产生的不确定度。     

火焰原子吸收测定固体样品中铅的测量不确定度分析

[目的]探讨火焰原子吸收光谱法测定固体样品中铅的测量不确定度的方法。[方法]用原子吸收仪测定茶叶样品中的铅含量,根据数学模型从样品取样、样品定容、标准储备液配制标准曲线、标准曲线线性回归方程和重复测量5个方面进行测量不确定度的计算。[结果]当样品中铅的含量为1.08 mg/kg时,其测量不确定度为0.06 mg/kg。[结论]通过建立数学模型,分析多方面的影响因素,可对火焰原子吸收测定固体样品中铅的测量不确定度进行合理的评定。     

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.     

The human drama of genetics: 'hard' and 'soft' media representations of inherited breast cancer

This paper examines media coverage of 'breast cancer genetics', and explores its implications for public understanding. We present a content analysis of coverage in British newspapers and look at a variety of popular forms, including women's magazines, television soap opera and radio drama. Genetic/inherited risk receives a great deal of coverage across a wide range of media formats and outlets. Much of this attention has focused on individuals from 'high risk families' and dilemmas around prophylactic mastectomies. Through examining media coverage, combined with interviews with media personnel and their sources, we show why this story proved so attractive to the media and highlight the different production values which influence coverage. Finally, we introduce preliminary findings from focus group discussions to demonstrate how such 'human interest' framing has engaged audience attention and influenced public understandings. The paper concludes by highlighting the implications for analysing, predicting, and engaging with, media representations of science.     

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.     

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.     

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.     

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.