牛奶中乳糖和乳果糖离子色谱电化学修饰法测定

目的用离子色谱电化学修饰方法测定牛奶中的乳糖和乳果糖,为建立这种淋洗液价廉,无毒,测定方法简单,灵敏度大大提高的分析测试方法提供依据.方法本实验采用离子色谱分离、碳纳米管修饰电极、脉冲安培检测,Dionex CarboPae PA1(2 mm×250 mm)分离柱 Dionex CarboPac PA1(2 mm×50 mm)保护柱,以5 mmol/L氢氧化钠 1 mmol/L乙酸钠为淋洗液测定牛奶中的乳糖和乳果糖.结果该方法具有良好的重现性、线性关系和较低的检测限.修饰后,乳糖和乳果糖的检测限分别是0.0007、0.0006 mg/L;样品测定的回收率分别为95%～105%.结论采用离子色谱电化学修饰方法测定牛奶中的乳糖和乳果糖,测试结果表明,该方法的准确度、精密度均较好,满足分析测试要求,采用碳纳米管修饰电极测定,使峰高和峰面积都显著提高,从而大大地提高了检测的灵敏度,是一种简便快速、分离效果良好的分析方法.     

碳纳米管修饰电极安培检测器离子色谱法测定儿茶酚胺类化合物

目的用碳纳米管修饰电极安培检测器离子色谱方法测定儿茶酚胺类化合物,为建立一种测定方法简单、灵敏度大大提高的分析测试方法提供依据。方法本实验采用离子色谱分离、碳纳米管修饰电极、直流安培检测,Dionex Ion Pac CS12分离柱(2 mm×250 mm)和Dionex Ion Pac CG12保护柱(2 mm×50 mm),以10 mmol/L硫酸溶液-10%乙腈溶液为淋洗液测定儿茶酚胺类化合物。结果该方法具有良好的重现性、线性关系和较低的检测限。修饰前被测物的检出限为0.000 3 mg/L~0 007 2 mg/L,修饰后的检出限为0.000 04 mg/L~0.000 09 mg/L,样品测定的回收率为96%~102%。结论该方法的准确度、精密度均较好,可以满足分析测试的要求。采用碳纳米管修饰电极测定,使峰高和峰面积都显著提高,从而大大提高了检测的灵敏度,是一种简便快速、分离效果良好的分析方法。     

碳纳米管修饰安培检测离子色谱电化学法测定饮料中的抗坏血酸

目的:用离子色谱电化学修饰方法测定饮料中的抗坏血酸,为建立这种测定灵敏度大大提高的分析测试方法提供依据。方法:采用Dionex AG9-HC(2 mm×50 mm) Dionex AS9-HC(2 mm×250 mm)分离,流动相为9 mmol/L碳酸钠水溶液,流速0.25 ml/min,碳纳米管修饰电极、直流安培检测。结果:该方法的线性范围是0.2~10.0 mg/L;修饰前,抗坏血酸的检出限为0.0005 mg/L,修饰后,抗坏血酸的检出限为0.00001 mg/L,方法回收率为85%~103%。结论:该方法具有选择性好,灵敏度高等优点,用于抗坏血酸的检测,结果令人满意。     

水中微量苯酚的碳纳米管化学修饰电极测定法

目的探讨应用多壁碳纳米管膜修饰电极测定环境水样中微量苯酚。方法制备了多壁碳纳米管膜修饰电极,采用循环伏安法和方波伏安法,测定环境水样中微量苯酚,同时还研究了苯酚在此修饰电极上的电化学行为。结果在pH7.0的磷酸盐缓冲溶液中,苯酚在多壁碳纳米管修饰玻碳电极上出现一灵敏的氧化峰,峰电位为0.69V。与裸玻碳电极相比,多壁碳纳米管膜修饰电极能显著提高苯酚的氧化峰电流。苯酚的线形范围为4.0×10-8～1.0×10-5mol/L,检测限可达1.0×10-8mol/L。5.0×10-7mol/L苯酚平行测定10次的相对标准偏差为5.2%。结论该电化学方法可用于环境水样中微量苯酚的测定。     

水中壬基酚的电沉积碳纳米管修饰电极差分脉冲伏安测定法

目的水样中壬基酚的电沉积碳纳米管修饰电极差分脉冲伏安测定法。方法采用脉冲电沉积法在碳纳米管(CNTs)和氯化钾的混合溶液中制备得到CNTs-玻碳电极(GCE),采用循环伏安法于0.2～1.2 V对壬基酚在修饰电极上的电化学行为进行研究,采用差分脉冲伏安法于0.2～1.2 V优化检测条件并对壬基酚的含量进行测定。结果碳纳米管修饰电极对壬基酚具有明显的电催化作用,电极反应过程是扩散控制过程。催化氧化峰电流与壬基酚浓度在0.1～10.0μmol/L范围内呈良好的线性关系,回归方程为i_(pa)=0.452 4+0.162 1 c,r=0.952 1。该方法的检出限为0.05μmol/L,平均回收率为98.0%～102.0%,RSD为1.3%～2.7%。结论该方法简便、快捷、灵敏度高,适用于水样中壬基酚的测定。     

铋膜/羧基化多壁碳纳米管修饰玻碳 电极测定水中六价铬

目的 构建铋膜/羧基化多壁碳纳米管修饰的玻碳电极（Bi/CMWCNTs/GCE）电化学传感器检测水中六价铬（Cr(VI)）。方法 将羧基化多壁碳纳米管（CMWCNTs）修饰的玻碳电极浸入100 mg/L Bi(NO3)3溶液中，用电化学沉积法得到Bi/CMWCNTs/GCE，再用差分脉冲溶出伏安法(DPSV)检测水中六价铬。结果 在最优实验条件下，Cr(VI)在-1.26 V处出现明显的溶出峰。在0.50～40.0 μg/L范围内，Cr(VI)浓度与相应的溶出峰电流间有良好的线性关系，线性回归方程为 y=1.037x+31.41， 相关系数 r =0.9995，检出限0.18 μg/L，加标回收率在95.07%～105.30%之间，RSD为1.81%～3.98%。结论 羧基化多壁碳纳米管和铋膜复合修饰玻碳电极，显著提升了修饰电极的表面活性，该方法灵敏度高，检出限低，绿色环保，适用于水中六价铬的检测。     

动物性食品中盐酸克仑特罗残留检测色谱条件优化

目的优化动物性食品中盐酸克仑特罗残留的高效液相色谱法(HPLC)检测条件,建立可大批量测定样品的方法。方法样品经高氯酸溶液超声提取,乙酸乙酯-异丙醇萃取,有机相浓缩后,采用Agilent C18(150 mm×4.6 mm,5μm)色谱柱进行分离,流动相为甲醇-磷酸二氢钠溶液,采用高效液相色谱仪进行分析。结果标准物质在0.2~10.0μg/m L时,方法的线性关系良好,相关系数(r)=0.999 84;方法的检测限为0.15μg/kg,低于国标方法的0.5μg/kg。盐酸克仑特罗保留时间为6.51 min,峰形良好;加标质量为1.6~12μg时,加标回收率为92.86%~100.93%,高于国标方法 (89.79%~92.36%);日内精密度和日间精密度均小于5%,低于国标方法。结论优化后的色谱条件适用于动物性食品中盐酸克仑特罗的大批量测定。     

反相离子对液相色谱法测定复合消毒剂中的3种苯扎氯铵

目的 优化色谱条件,建立反相离子对液相色谱法检测复合季铵盐消毒剂中3种苯扎氯铵的含量。方法 采用岛津C18色谱柱,以0.01 mol/L庚烷磺酸钠为离子对试剂,醋酸铵（0.02 mol/L,30%）-甲醇（70%）为流动相,检测波长260 nm,外标法测定复合消毒液中的十二烷基二甲基苄基氯化铵、十四烷基二甲基苄基氯化铵和十六烷基二甲基苄基氯化铵。结果 3种苯扎氯铵在C18色谱柱上分离良好,标准曲线的线性范围20.0～1 000.0 mg/L,检测限1.7～5.9 mg/L。样品加标回收率96.3%～102.5%,相对标准偏差小于3.0%。结论 建立的反相离子对液相色谱法能够同时测定消毒剂中3种苯扎氯铵,该方法具有专属性强、重现性好和灵敏度高的优点,适用于复合季铵盐消毒剂中苯扎氯铵的测定。     

碳纳米管-离子液体纳米流体修饰电极用于尿酸的测定

目的:用碳纳米管-离子液体纳米流体修饰玻碳电极,构建测定尿酸的电化学传感器。方法:将构建的电化学传感器置于尿酸的磷酸盐缓冲溶液中,实验结果表明,尿酸在修饰电极上产生一氧化峰,峰电位为0.570 V(vs.SCE),较裸电极负移0.170 V,且峰电流大大增强。据此,建立了测定UA的电化学分析方法。结果:在选定的最佳实验条件下,用线性扫描循环伏安法(LSV)测定尿酸的线性范围为5×10-6mol/L~8×10-4mol/L,检出限为5.5×10-7mol/L。结论:该方法可直接用于人体尿液中UA的测定,结果满意。     

毛细管区带电泳分离/电化学检测果汁中有机酸

目的:建立毛细管区带电泳分离/电化学检测果汁中有机酸的方法。方法:以溴化十六烷基溴化吡啶(CPB)作电渗流反向修饰剂,在电泳溶液中添加-环糊精(-CD)以提高分离选择性,并进行分离条件的优化,实现了草酸、柠檬酸、苹果酸、酒石酸、琥珀酸、延胡索酸六种有机酸的基线分离.采用纳米钯修饰碳糊电极安培检测器分别加以测定。结果:本法对有机酸检测限(S/N=3)低于2mol/L,线性范围在2个数量级以上(110–6~1.010–3mol/L),相对标准偏差1.05%～2.15%,加标回收率93.4%。结论:本法快速,灵敏度高,选择性强,适合于果汁中几种有机酸的同时测定。     

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.     

The occurrence of antimicrobial substances in toilet,sink and shower drainpipes of clinical units: A neglected source of antibiotic residues

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference.To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02?μg·L^?1 to a maximum of 79?mg·L^?1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance.     

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.     

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.     

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.