微波消解—磷钼蓝分光光度法测定奶粉中的磷

目的建立用微波消解进行奶粉前处理,磷钼蓝分光光度法测定奶粉中磷含量的新方法。方法分别用酸消解法及微波消解法消解奶粉样品,消解液按国标方法—磷钼蓝分光光度法显色后于660nm波长处测定吸光度;并考察了溶液吸光度随时间变化情况及减少显色剂用量对测定结果的影响。结果标准系列磷含量在0～60μg时,磷含量与吸光度成线性,相关系数0.9999;奶粉经微波消解前处理测得的磷含量,与国标的酸消解法相比差异无显著性;测定奶粉标准物质,测定值在标准参考值标识范围内。结论该微波消解条件对奶粉进行前处理,操作简单、快速,试剂用量少,结果准确,适合于奶粉中磷含量的测定。     

食品中磷含量检测方法探讨

目的完善食品中磷含量检测方法,为调查分析婴幼儿食品、蔬菜水果、粮食制品、肉类制品中磷的含量提供保障。方法参考国家标准GB／T5009．87～2003《食品中磷的测定》第1法分光光度法,在显色刺的浓度及还原剂的配制等方面作了有效的调整,并比较了湿法消解和微波消解对样品进行前处理的测定结果。结果该方法测定食品中磷标准曲线线性范围为O～2．4μg／mL（r=0．9998）,方法检出限（LOD）为20mg／kg,方法定量限（LOQ）为60mg/kg,方法回收率为100．1％～100．7％,精密度为0．24％～0．32％。分别采用湿法消解和微波消解前处理样品,对标准物质各进行6次测定,测定均值分别为4．31、4．40mg／g,两者差异无统计学意义（P〉0．05）。结论改进后的方法易于操作,测定结果准确度和精密度好,对于有微波设备的实验室,样品前处理采用微波消解更能提高工作效率、减少环境污染。     

市售冷冻酸奶中钙 磷含量的测定分析

目的:通过测定冷冻酸奶中钙磷含量来了解其营养价值及产品开发。方法:使用干法消解处理样品,消解液用原子吸收分光光度法测定样品中钙的含量,用磷钼蓝分光光度法在660nm波长处测定样品中磷的含量。结果:采用原子吸收分光光度法测定样品中钙的含量,得出吸光度与浓度之间的线性关系曲线,相关系数为0.99626;用磷钼蓝分光光度法测定样品中磷的含量在0～80μg时,磷的含量与吸光度呈线性关系,相关系数为0.9998;用本法测定冷冻酸奶中的钙、磷含量,测定值的相对标准偏差分别为1.03%和0.89%,对样品的加标回收率在100.4%～110.7%之间。结论:冷冻酸奶的钙磷含量较高,接近于酸奶,且其钙磷比例在1∶1.4～1∶2.0之间,更接近于文献所述的最佳钙磷比例,即Ca∶P=2∶1,适宜人体吸收。     

不同消解技术在食品磷脂测定中的应用

目前 ,测定食品中磷脂的方法较多 ,其中有钼蓝定性法、纸层析定性法、喹钼柠铜重量法、分光光度法 (定量 )及高压液相色谱法 ,但高压液相色谱法仪器昂贵且需磷脂各种标准品。本文就磷脂蛋白乳中大豆磷脂的含量采用分光光度法进行定量 ,并对样品前处理方法进行了研究 ,分别用干法、湿法、微波消解法对样品进行分析 ,三种消解方法适用于实际样品的分析测试。1　实验部分1.1　分析原理　样品中的磷脂经酸氧化 ,使磷在酸性条件下与钼酸铵结合生成磷钼酸铵。此化合物经对苯二酚、亚硫酸钠还原成蓝色化合物—钼蓝。用分光光度计在波长 660nm处测钼…     

微波消解-钼蓝比色法测定肉制品中磷酸盐

目的：建立微波消解-分光光度法进行肉制品中磷酸盐的测定。方法：运用微波消解技术进行样品消解,再以钼蓝比色法进行含量测定。结果：本法的精密度RSD（%）在1.1～3.4之间,回收率（%）在86.1～87.6之间。结论：利用微波消解技术进行肉制品中磷酸盐的含量测定,缩短了消解时间,简化了操作步骤,并使精密度和准确度均得到改善。     

面制食品中铝的可见分光光度测定法中样品前处理方法的探讨

目的建立可见分光光度法测定面制食品中铝的一种简单可行的前处理方法。方法样品分别经干法灰化、2种湿法消化和微波消解前处理后,用可见分光光度法测定馒头、油条和粉丝3类面制食品中的铝含量。结果①干法灰化前处理时,相对标准偏差为0．2％～0．9％,方法回收率为91．0％～98．6％;适合3类面制食品前处理;②硝酸／高氯酸（国标）法前处理时,相对标准偏差为0．1％～1．0％,方法回收率为91．0％～96．8％;适合馒头和粉丝样品前处理。③硝酸回流消化时,相对标准差为0．1％～0．9％,方法回收率为98．0％～99．5％;适合馒头和粉丝样品前处理。④微波消解前处理时,相对标准偏差为0．1％～0．9％,方法回收率为98．5％～99．2％;适合3类面制食品前处理。结论干法灰化法是一种简单、快速、安全及结果准确的前处理方法,同时适合各种样品的批量处理。     

测定牛奶中磷的微波消解技术

磷是组成生命不可缺少的重要物质。是核酸、细胞膜、磷蛋白及某些辅酶的组成成分，参与物质代谢，维持酸碱平衡。膳食中钙与磷的比例直接影响到骨骼的发育，牛奶中钙磷比值为2：1时，就非常接近母乳中钙磷比值，有利于钙在肠道中的吸收。因此，对牛奶中磷的测定就显得非常重要。国家标准方法测定食品中磷的消解方法为湿法消解，湿法消解是在加热条件下用强氧化剂如硝酸、硫酸、高氯酸等分解有机物，其缺点是试剂用量大，在消解过程中产生大量酸雾危害工作人员身体健康和污染环境。近年兴起的微波消解技术在试样前处理中以快速、分解完全、酸耗量少等优点，日益受到青睐。微波与传统的加热区别在于它可直接穿透样品的内部，里外同时加热，缩短了分析时间，我们采用微波消解技术对牛奶进行前处理，以磷钼蓝分光光度法测定牛奶中磷的含量。     

电感耦合等离子体发射光谱法测定食品中的磷

目的：建立电感耦合等离子体发射光谱法测定食品中磷的检测技术。方法：利用微波消解技术处理食品样品，同时结合电感耦合等离子体发射光谱法检测样品中磷的含量。结果：本方法测定食品中的磷，当磷溶液浓度范围在0．02～10．00mg／L时，标准回归方程Y=321．2X～6．825，相关系数r=0．9999，线性回归良好；回收率范围为91．2％～104．8％；相对标准差为1．0％、1．2％；本法最低检出限为10mg／kg。采集12组样本用国标法与本方法作对照，经统计学检验，P=0．383〉0．05，表明两种方法差异无显著性。绪论：本方法在用于检测食品中磷时与国标法同样有效，并且回收率高、精密度高，可用于食品中磷的检测。     

微波消解和湿式消解在ICP—AES法中的应用比较

目的比较微波消解和湿式消解前处理法在等离子体发射光谱法（ICP—AES）测定食品中金属元素的应用效果。方法将微波消解和湿式消解法用于实际样品包括奶粉、乳饮料、白酒、面粉、水产品、肉制品、饮料等的测定，并对这2种方法进行比较。结果微波消解方法的检出限为0．0011～0．0218mg／L，可以满足测定的要求，不同元素RSD为0．23％-2．61％，回收率为90．6％～95．1％，对2种方法处理样品测定结果的试验数据进行统计学分析，确定各种元素差异均无统计学意义。结论微波消解前处理方法具有简便、快捷、回收率高、精密度高的优点，该方法适用于食品中金属元素的测定。     

钼蓝比色法测定骨质疏松模型大鼠的骨磷含量

目的建立骨质疏松模型大鼠骨磷含量测定的钼酸铵紫外分光光度法。方法通过维甲酸诱导大鼠骨质疏松模型。实验结束后处死大鼠,取左侧股骨,高温灰化后,用硝酸对样品消解,再以钼蓝比色法进行骨磷含量测定。结果样品消解完全,骨磷含量线性范围在0.228～1.824mg/l(r=0.9998),回收率在97.8%～100.2%之间。结论本方法操作简单、快速、准确,可用于对骨质疏松模型大鼠骨磷含量的测定。     

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.     

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.     

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.