动力学荧光法测定食品中甲醛

目的:建立动力学荧光法测定食品中微量甲醛。方法:在稀硫酸介质中,甲醛对溴酸钾氧化吡啰红Y的反应具有较强的催化作用,使体系溶液的荧光减弱,利用荧光减小的程度与甲醛含量的定量关系,进行微量甲醛的动力学荧光法测定。结果:该催化反应在沸水浴中进行15 m in,为假零级反应。测定甲醛的线性范围为0.08~0.8 mg/L,检出限为4.8×10-5g/L。结论:本法用于食品中微量甲醛的测定,并进行加标回收实验,回收率在97.1%~102.0%之间。     

共振光散射法测定痕量甲醛

目的:建立测定环境样品中微量甲醛的催化共振光散射新方法。方法:基于硫酸介质中,甲醛能催化溴酸钾氧化吖啶橙的反应,使其共振光散射强度减弱。采用单因素转换法优化反应条件;采用化学热力学方法研究催化反应的性能和机理。结果:新建方法测定甲醛的浓度线性范围为0.025~0.25μg/m l,检出限6.13×10-6μg/m l。RSD为1.30%、0.24%,样品加标回收率为95.5%~96.2%。结论:新建方法简便快速,选择性好,用于环境水样、室内空气中甲醛的测定,结果满意。     

湿法消解砷铈催化分光光度法测定奶粉中碘含量的方法研究

目的建立简便快速消解奶粉样品,实现其总碘含量测定的方法。方法用高氯酸、氯酸钾混合湿法消解样品溶液2小时,用砷铈催化分光光度法测定其碘含量。由吸光度值与碘浓度的对应关系,计算出样品中碘的含量。结果检测范围0~100μg/L,标准曲线相关系数为-0.999 6~-0.999 9;精密度:测定奶溶液样品中碘含量为20.11μg/L、60.45μg/L和86.55μg/L时,变异系数(CV)分别为2.54%、1.85%和1.58%;准确度:对低、中、高3种不同浓度碘含量的奶粉溶液加标回收率分别为98.90%、101.02%和99.66%(n=6),平均回收率为99.86%。结论本方法适合应用于奶粉中总碘的含量测定。     

氢化物发生-原子荧光法同时测定食品中砷和铅

目的 :建立一种同时测定食品中微量砷和铅的方法。方法 :采用灰化法消解样品 ,氢化物原子荧光法同时测定食品中微量砷和铅。结果 :方法检出限砷和铅分别为 0 .30 μg/ L 和 0 .32 μg/ L;砷和铅的回收率分别为 85 .2 %～ 10 8%和89.7%～ 10 3.3% ;相对标准偏差分别为 2 .0 %～ 5 .1%和 3.2 %～ 5 .5 %。结论 :食品中微量砷和铅可以用氢化物原子荧光法同时测定     

分光光度法测定食品中硼砂

目的 :建立姜黄素分光光度法测定食品中硼砂含量的方法。方法 :食品在碱性条件下灰化 ,在酸性条件下姜黄素分光光度法测定硼砂含量。结果 :方法的线性好 (r=0 .9999) ,样品测定的相对标准差 rsd<5 % ,加标回收率为 90 .0 %～ 10 4 .5 % ,检出限为 0 .0 6 mg/kg。结论 :该方法灵敏、准确、精密、易于操作 ,适用于食品中硼砂测定     

离子色谱法同时测定牙膏中的单氟磷酸盐与游离氟的研究

目的:采用离子色谱法同时测定牙膏中单氟磷酸盐与游离氟的含量。方法:色谱柱为DIONEXIonpacAS14 -4mm,以2. 0mmol/LNa2CO3 /2 5mmol/LNaHCO3 为淋洗液,流速为1. 2ml/min,抑制电流: 50mA,电导检测。结果:该方法游离氟F-与单氟磷酸盐MFP2-线性范围分别为0. 1~10 .0mg/L, 0. 5~50mg/L,相关系数均大于0 999(n=5);最低检测限分别为2. 6×10-5 mg/L, 1 3×10-4 mg/L;样品测定相对标准偏差分别为1 66%, 0 79%;回收率分别为93 .0% ~102. 0%, 102 .9% ~106 .4% 之间。结论:该方法操作简便,能同时测定牙膏中游离氟与单氟磷酸盐的含量,具有准确、快速等特点。     

小麦粉中吊白块检测方法的研究

目的研究催化动力学光度法测定小麦粉中吊白块的方法。方法在硫酸介质中,甲醛可灵敏地催化溴酸钾氧化中性红的退色反应。选择研究了该催化反应中多项测定条伴,参照建立了催化动力学光度法测定痕量甲醛的方法,又对产生假阳性问题的多个干扰因素进行了研究。结果甲醛含量的检测范围为(0.20~1.0)μg/25 ml;该方法的检出限为0.0400μg/25 ml,标准偏差4.45%,加标回收率为91.3%。结论催化动力学光度法测定小麦粉中痕量甲醛的方法是可行的。     

环境空气中现场测定手持式甲醛测定仪的研制

目的　建立一种现场测定环境空气中甲醛含量的灵敏、快速、廉价方法。方法　在自行研制的手持式高灵敏光度计的基础上 ,研制一种动态线性范围宽、样品和试剂用量少、分析速度快、无可动部件、灵敏度高、结构简单、轻便耐用、耗电量低的手持式甲醛测定仪 ,同时开发一种甲醛测定专用试剂包。结果　使用本方法测定甲醛的线性范围是0 0 0 1～ 0 3mg/L ,定量检测下限为 0 0 0 1mg/L ,线性相关系数为 0 999,测定的相对误差在± 5 %以内。 结论　本仪器用于环境空气中甲醛的现场测定 ,结果满意。     

茶水中锌含量分析方法研究

目的:建立测定茶水中锌含量的方法。方法:采用锌试剂吸光光度法测定茶水中锌含量。结果:在一定条件下,锌含量在0~80μg/25 ml范围内遵守朗伯比耳定律,方法的精密度(RSD)在1.38%~3.27%之间,回收率在94%~107%之内,检测限为5.2μg/L,表观摩尔吸光系数为2.2×104L/mol.cm。结论:本方法经用于茶水样品分析,结果符合要求。     

酚试剂分光光度法测定饮用水中甲醛

目的 建立测定饮用水中甲醛方法.方法 利用水溶液中甲醛与酚试剂反应生成嗪,嗪在酸性溶液中被高铁离子氧化成蓝绿色化合物,产生颜色与甲醛含量成正比的原理,采用酚试剂分光光度法对饮用水中的甲醛含量进行测定,并与AHMT分光光度法比较.结果 本方法的线性范围0.005～0.100 mg/L,检出限为5×10-4mg/L,RSD为1.02%～1.17%,样品加标回收率为96.4%～107.2%.结论 该法用于实际水样检测,结果满意.     

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.     

Worker education in the primary prevention of occupational dermatoses

This paper reports the evaluation of a skin care education programmeconducted on a fine chemicals manufacturing site where over1,000 employees are located. Approximately 60% are involvedin chemical manufacture. Over a 12 month period production staffreceived training in prevention of occupational dermatoses linkedto a site-wide poster initiative. The incidence of new casesof occupational dermatoses fell from 0.055 (70 cases in 1,277employees) to 0.021 (27 cases in 1,277 employees) before andafter the intervention respectively (p<0.0001). After otherfactors such as chemicals handled, observer bias and changesin reporting related to socioeconomic climate were taken intoaccount it is concluded that this study demonstrates the importanceof worker education as a tool for primary prevention of disease.Training materials such as video and poster presentations maybe effectively used in the chemical manufacturing industry asan adjunct to prevention and control of exposure to substanceshazardous to the skin. Such methods may also be used in otherindustries where there are significant risks of dermatoses.