微波消解-铬天青S分光光度法测定面制食品中铝

目的:建立微波消解-铬天青S分光光度测定面制食品中铝的方法,选择最佳测定条件,保证检测结果质量。方法:样品经微波消解处理后,三价铝离子在乙酸-乙酸钠缓冲介质中,与铬天青S及溴化十六烷基三甲胺反应形成蓝色三元络合物,用分光光度法与标准比较定量。结果:25℃时蓝色三元络合物在10~30 m in稳定,最大吸收波长638 nm,在0.5μg~9μg/25 m l之间的线性关系良好,相关系数在0.9991~0.9996之间,相对标准偏差为≤3.5%,加标回收率在95.0%~104.7%,最低检测限为0.1μg/25 m l。结论:方法精密度好、准确度高,能满足面制食品中铝含量测定的要求。     

微波消解-快速赶酸-分光光度法测定大拉皮中铝含量

目的建立了微波消解-快速赶酸-分光光度法测定大拉皮中铝的方法。方法拉皮样品经硝酸-双氧水消解体系微波消解后,于赶酸器上220℃快速赶酸,用分光光度法测定铝含量,结果铝在0μg~0.24μg/m L的线性范围内线性关系良好,所得回归方程为y=3.63x+0.013,R=0.999 9。该方法的检出限为5.4μg/L,平均回收率为93.4%~98.2%,RSD为0.84%~4.3%。结论该方法操作简便,安全,快速,精密度、准确度均较高,适合拉皮样品中铝的测定。     

控温消解-火焰原子吸收法测定红细胞中钾钠钙镁

[目的]建立一种简便、快速、准确的红细胞内钾钠钙镁原子吸收测定方法。[方法]利用控温消解仪,硝酸—过氧化氢消解红细胞样品,用火焰原子吸收分光光度法测定钾钠钙镁。[结果]该法与微波法消解相比测定结果差异无显著性。钾钠钙镁的方法检出限分别为0.002μmol/g,0.0005μmol/g,0.003μmol/g和0.0001μmol/g;相对标准偏差分别为2.2%,4.1%,2.1%和3.5%;加标回收率97.2%~102.6%,94.6%~104.7%,95.9%~102.3%和95.4%~104.3%。[结论]本法测定红细胞内钾钠钙镁方法简便,试剂用量少,准确可靠,适合用于批量血样的分析测定。     

微波消解-分光光度法测定油炸食品中的铝

目的建立微波消解法处理样品,铬天青S作显色剂分光光度法测定食品中铝含量的方法。方法样品经微波消解,以氨水调解pH值6.7~7.0近中性条件下,铬天青S作显色剂,加OP乳化剂在波长620 nm,2 cm比色杯测定食品中铝的吸光度,与标准曲线比较定量。结果铝含量在0.5~10.0μg/50 ml呈良好的线性关系,相关系数r=0.999 9,RSD为:1.64%~4.41%,回收率在88.2%~108%。结论样品经微波消解后,结果准确,回收率高,满足食品中铝的测定。     

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。     

催化分光光度法测定痕量苯酚

目的:建立测定痕量苯酚的新方法。方法:基于硫酸介质中,苯酚能催化溴酸钾氧化茜素红的褪色反应,建立了催化分光光度法测定痕量苯酚的新方法。结果:方法的线性范围为0.08~1.20μg/m l,检出限0.046μg/m l。RSD为1.92%、2.24%,样品加标回收率为97.5%~104.0%。结论:该方法简便快速,常见物质干扰小,用于环境水样痕量苯酚的测定,结果满意。     

分光光度法测定消毒剂中的甲醛

用乙酰丙酮分光光度法测定消毒剂中的甲醛。结果表明 ,甲醛的线性范围在 0～ 10μg/ml之间 ,检测下限为 0 .0 8μg/ml,不同浓度样品的精密度小于 3.9% ,加标回收率为 10 0 .2 %～ 10 8.2 % ,与容量法相比较差异无显著性。与其它分光光度法相比 ,该法具有操作简便、重现性好、灵敏度高、选择性好等优点 ,适合测定用容量法有干扰时消毒剂中的甲醛。     

微波消解-氢化物发生原子荧光光谱法同时测定食品中汞和砷

目的:建立微波消解-氢化物发生原子荧光光谱法同时测定食品中汞和砷的方法。方法:食品样品经微波消解后,用氢化物双道原子荧光光谱法同时测定食品中汞和砷的浓度。结果:本法在汞浓度为0μg/L～1.0μg/L、砷浓度为0μg/L～10μg/L范围内有良好的线性关系,相关系数rHg=0.9998,rAs=0.9997,检出限为Hg:0.0002 mg/kg,As:0.005 mg/kg;相对偏差为Hg:1.2%,As:0.83%;回收率为Hg:85%～91%,As:94%～103%。结论:该方法具有简便、快速、灵敏度高等优点,适合日常批量检测。     

微波消解-分光光度法测定食品中蛋白质

食品中蛋白质的国家标准检验方法凯氏定氮法,样品前处理试剂用量大,消化时间长,大量的酸雾对操作人员易产生伤害;样品分析要蒸馏、滴定,测定一个样品需近2 0 min。本文采用微波消解样品,减少了试剂用量,缩短了消化时间,一次可同时消化6个样品。而采用分光光度法测定蛋白质,取样量少,操作简便、快速,回收率为94 .5 %～10 8.7% ,相对标准偏差为2 .6 4 %～5 .0 5 % ,结果令人满意。1　材料和方法1.1　原理　食品中的蛋白质,加入硫酸和过氧化氢,经微波消解后,蛋白质分解,分解的氨与硫酸结合成硫酸铵,在p H= 4 .7的乙酸盐介质中,铵盐与乙酰丙酮…     

微波消解-原子荧光法测定食品中总砷

目的建立应用微波消解-原子荧光法快速、准确地测定食品中总砷的方法。方法采用微波消解法对食品样品进行前处理,氢化物发生原子荧光法测定食品样品中总砷。结果砷的质量浓度在0~10μg/L范围内与原子荧光强度呈良好的线性关系,相关系数为0.999 4,方法检出限为0.006 mg/kg,回收率为96.1%~104.9%。结论本方法能简便、准确地测定食品中总砷。     

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.     

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.