萘乙二胺-亚硝酸根体系共振散射光谱研究及分析应用

目的：建立测定痕量亚硝酸根的新方法。方法：基于盐酸介质中，亚硝酸根与萘乙二胺发生亚硝化反应，亚硝化产物在碱性溶液中聚集，产生了强烈的共振散射现象．据此建立了共振散射光谱法测定亚硝酸根的新方法。结果：方法的线性范围为0～800ng／ml，检出限7．3ng／ml。样品加标回收率为99．6％-103．5％。结论：该方法简便快速，常见物质干扰小，用于蔬菜中痕量亚硝酸根的测定，结果满意。     

表面活性剂增敏催化共振光散射法测定痕量亚硝酸根

目的：建立测定痕量亚硝酸根的新方法。方法：基于硫酸介质中，亚硝酸根催化溴酸钾氧化健那绿的反应，使其与十二烷基苯磺酸钠缔合的共振光散射强度减弱，据此建立了催化共振光散射分析法测定亚硝酸根的新方法。结果：方法的线性范围为0．83—41．67ng／ml，检出限0．70ng／ml。RSD为1．32％、1．24％，样品加标回收率为96．1％-103．9％。结论：该方法简便快速，常见物质干扰小，用于环境水样痕量的亚硝酸根测定，结果满意。     

双波长双指示剂催化动力学光度法测定痕量亚硝酸根

目的：建立测定痕量亚硝酸根的新方法。方法：在稀磷酸介质中，基于亚硝酸根对溴酸钾氧化甲基橙和甲基紫褪色的指示反应，通过测量500nm和600nm下，催化体系和非催化体系吸光度的变化，用双波长双指示剂催化动力学光度法测定痕量亚硝酸根。结果：在实验条件下，亚硝酸根浓度在0—0．60μg/ml之间存在线性关系（r=-0．999）。方法检出限为0．025μg/ml。结论：该法简单，灵敏度高，选择性好，可用于环境水样中痕量亚硝酸根的测定。     

亚硝酸根重氮化-偶联反应共振散射光谱测定

目的研究重氮化-偶联反应的共振散射光谱并应用于亚硝酸根的测定。方法利用磺胺-N,N-二甲基苯胺-亚硝酸根间发生的重氮化-偶联反应,通过共振散射光谱法测定痕量亚硝酸根。结果方法的线性范围为0~1.2×10^-3g/L,检出限为8.0×10^-5g/L。结论该方法简单、灵敏度高、选择性好,用于蔬菜中亚硝酸根含量的测定,回收率为92.8%~98.5%。     

催化荧光法测定水中痕量亚硝酸根

基于在硫酸介质中 ,痕量亚硝酸根可催化溴酸钾氧化中性红褪色的反应 ,建立了一种催化荧光法测定痕量亚硝酸根的新方法 ,并研究了方法的动力学条件和多种常见离子的干扰情况。方法的选择性和灵敏度较高。亚硝酸根的线性范围为 0 .0 2～ 5 ng/ ml。方法的检出限 CL为 0 .0 1 3 ng/ ml。用于水中痕量亚硝酸根的测定 ,结果满意     

共振光散射法测定磺胺类药物

目的:建立测定痕量磺胺类药物的新方法.方法:基于磺胺类药物-亚硝酸根-8-羟基喹啉的重氮化-偶联反应.偶联反应产物使得468 am处共振散射光强度明显增加,从而建立了测定磺胺类药物的新方法.结果:磺胺、磺胺噻唑、磺胺甲恶唑和磺胺甲嘧啶的线性范围分别是:10～1500μg/L、50～1500 tLg/L、10～1500μg/L、10～1500μg/L;检出限分别为:8.3、12、7.9.9.1μg/L;回收率为99.9%～101.1%.结论:方法的灵敏度高,线性范围宽,用于复方新诺明中磺胺甲恶唑含量的测定,结果满意.     

亚硝酸根-对硝基苯胺-8-羟基喹啉分光光度法测定亚硝酸根

目的：建立测定痕量亚硝酸根的新方法。方法：在盐酸介质中，亚硝酸根与对硝基苯胺发生重氮化，在强碱中再与8-羟基喹啉偶联，生成红色化合物，该化合物在波长530nm处有最大吸收。结果：在实验最适条件下，亚硝酸根浓度在0—0．8μg/ml之间存在线性关系（r=0．9998）。方法检出限为0．02μg/ml。RSD=1．4％-2．9％。样品加标回收率为95．7％～100．6％。结论：方法应用于环境水样中亚硝酸根的测定，结果满意。     

吖啶红荧光猝灭法测定痕量亚硝酸根

〔目的〕建立测定痕量亚硝酸根的新方法。〔方法〕在盐酸介质中 ,吖啶红与亚硝酸根发生亚硝化反应 ,其荧光强度降低 ,用吖啶红荧光猝灭值标准曲线法测定痕量亚硝酸根。〔结果〕在实验最适条件下 ,吖啶红的荧光猝灭强度与亚硝酸根的含量在 0 0 5～ 0 5 μg ml之间存在线性关系 (r =0 998)。方法的检出限为 7 5ng ml ;RSD =1 43 %～ 3 77% ;样品加标回收率为 90 40 %～ 10 0 3 0 %。〔结论〕方法操作简便 ,灵敏度高。用于环境水样中痕量亚硝酸根的测定 ,结果满意     

催化动力学光度法测定水中痕量铜

目的:建立催化动力学光度法测定痕量铜的新方法。方法:在pH4.2的邻苯二甲酸氢钾-氢氧化钠缓冲溶液介质中,利用铜离子催化氯酸钾和过氧化氢氧化灿烂绿的指示反应,通过测量624 nm下吸光度的改变,用催化动力学光度法测定痕量铜。结果:测定铜的线性范围为0.040~1.50μg/25 ml,检出限为8.6×10-11g/ml。对0.50μg/25 ml铜离子进行10次平行测定的相对标准偏差为3.2%。结论:该法简单,灵敏度高,选择性好,可用于水中痕量铜的测定。     

碱性品红-溴酸钾体系催化动力学光度法测定痕量钒

目的:建立催化动力学光度法测定痕量钒的新方法。方法:在柠檬酸介质中,利用钒对溴酸钾氧化碱性品红的催化作用,在536 nm处测量催化体系和非催化体系的吸光度的变化,用催化光度法测定痕量钒。结果:测定钒的线性范围:0.00100~0.0250μg/ml,检出限为5.7×10-11g/ml。结论:该法简单,灵敏度高,选择性好,可用于食品中痕量钒的测定。     

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.     

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.