面粉中过氧化苯甲酰高效液相色谱法测定方法探讨

目的：建立高效液相色谱法测定面粉中过氧化苯甲酰含量的检测方法。方法：用石油醚和乙醚(5：1)直接萃取面粉中的过氧化苯甲酰和苯甲酸，经C18分离柱，甲醇-0．02％乙酸铵水溶液(90：10)为流动相，流量1．0ml／min，检测波长230nm。结果：该方法同时测定面粉中过氧化苯甲酰和苯甲酸，两者线性范围5～100mg／L，r=0．999。过氧化苯甲酰检出限为0．00125g／kg，平均回收率97．3％，苯甲酸检出限为0．006g／kg，平均回收率97．2％。结论：样品无需还原便可直接进样分析，方法灵敏度高，回收率和重现性好，操作简单方便。     

高效液相色谱法测定面粉及其制品中过氧化苯甲酰含量的研究

目的 为了简便、灵敏地测定面粉及其制品中过氧化苯甲酰(BPO)的含量，建立了高效液相色谱法(HPLC)。方法 样品直接以乙醇超声提取，再用10％KI将BPO转化成苯甲酸，利用苯甲酸作标准对照品进行定性定量。采用ODS柱，以甲醇-0．02moL／L乙酸铵(6 94)为流动相，流速1ml／min，检测波长220nm。结果 苯甲酸浓度在0～100mg／L范围内显良好的线性关系(r=0．9998)，方法回收率为90．1％～102．4％，RSD为1．83％～3．82％，最低检出浓度为0．004g／kg。结论 试验表明本法简单方便，有较高的灵敏度和较好的准确性。     

高效液相色谱法测定食品中安赛蜜

目的：建立食品中安赛蜜的高效液相色谱测定方法。方法：以甲醇-0．02mol／L乙酸铵溶液为流动相，C18柱分离，二级管阵列检测器检测。结果：方法线性范围在0．005—0．100mg／ml，最低检出限为0．005g／kg，相对标准偏差在1．3％一4．3％之间，回收率为96．0％-97．6％。结论：该方法灵敏、准确，重复性好，可用于食品中安赛蜜的测定。     

高效液相色谱法同时测定面粉中的过氧化苯甲酰和苯甲酸

目的:建立同时测定面粉中过氧化苯甲酰和苯甲酸的高效液相色谱法(HPLC)。方法:采用无水乙醇提取面粉中的过氧化苯甲酰和苯甲酸后,在Waters Symmetry C18柱上,以甲醇-0.05%磷酸水溶液(80:20)为流动相进行分离,HPLC-二极管阵列检测器(DAD)于235.5 nm测定。结果:过氧化苯甲酰和苯甲酸的最低检出限分别为0.14 mg/kg和0.20 mg/kg;过氧化苯甲酰的回收率和相对标准偏差分别为97.50%～101.60%和1.51%;苯甲酸的回收率和相对标准偏差分别为95.60%～104.20%和3.03%。结论:该方法具有准确、可靠、操作简便、检测限低等特点,适用于面粉中过氧化苯甲酰和苯甲酸的同时测定。     

面粉及面制品中过氧化苯甲酰的二极管阵列检测-高效液相色谱测定法

目的研究检测面粉及面制品样品中过氧化苯甲酰含量的前处理及测定方法，并对市售面粉及面制品中过氧化苯甲酰添加状况进行调查。方法用乙醇提取面粉及面制品中过氧化苯甲酰，碘化钾还原过氧化苯甲酰为苯甲酸，以高效液相色谱法二极管阵列检测器测定其含量，色谱条件：流动相为0．02mol／LNH4Ac水溶液：甲醇(96：4)，流速1．20ml／min，柱温40℃，检测波长225nm，进样量为10μl。结果方法检出限为0．005mg(以3倍噪声值计)，回收率在97．0％～1130．7％之间，精密度为1．21％(低浓度)和0．44％(高浓度)。调查147份面粉和102份面制品样品，阳性率84．3％，超标率29．3％，面制品超标率高于面粉。结论该方法测定面粉及制品中过氧化苯甲酰具有操作简单、干扰少、准确可靠等特点，可以在日常检测工作中推广；面制品用面粉过氧化苯甲酰卫生标准进行评价不合适，应采用食品中防腐剂苯甲酸的卫生标准。     

气相色谱法测定高脂类食品中山梨酸、苯甲酸的含量

目的：建立高脂类食品中山梨酸和苯甲酸的气相色谱毛细管色谱柱检测方法。方法：样品用石油醚-乙醚高速匀浆的方法提取后，通过改变其酸碱度而改变其在有机相和水相中分配比的方法，去除脂肪等杂质的干扰，用FFAP毛细管色谱柱FID检测器进行检测。结果：方法的相对标准偏差为1．2％-7．0％，回收率为85．0％。99．2％，最低检出限为1mg／kg。结论：该方法具有步骤简单、准确度和灵敏度高的特点．适用于高脂类食品中山梨酸和苯甲酸的检测。     

面粉中过氧化苯甲酰的高效液相色谱测定法

目的改进面粉中过氧化苯甲酰的测定方法，使其简便、准确，便于广泛应用。方法采用高效液相色谱法，样品先用无水乙醇超声提取，盐酸羟胺还原过氧化苯甲酰为苯甲酸，以C18柱分离，DAD检测。结果方法最低检出量为0．05μg，检出限0．020g／kg；平均回收率为103．1％，相对标准偏差为3．43％。结论方法灵敏、准确、适用于样品的日常检测。     

工作场所空气中过氧化苯甲酰高效液相色谱测定方法

目的：建立工作场所空气中过氧化苯甲酰的高效液相色谱测定方法。方法：空气中过氧化苯甲酰用微孔滤膜采集，乙醚洗脱，经C18色谱柱分离，紫外检测器检测。结果：本法的检出限为1．0μg／ml，最低检出浓度0．22mg／m^3（采集45L样品）。在1．0—200μg／ml范围内，线性关系良好，r=0．9999。RSD在1．7％-5．2％之间。平均加标回收率为99．2％。用微孔滤膜采样，样品可保存2周。结论：方法操作简便、灵敏，可用于工作场所空气中过氧化苯甲酰的采集及测定。     

固相萃取-高效液相色谱荧光检测法测定染色虾米中的碱性玫瑰精含量

目的：建立高效液相色谱-荧光检测法测定染色虾米中的碱性玫瑰精含量的检测方法。方法：样品经均质，无水乙醇-氨水-水(7 2 1)溶液浸提，SPE-HLB柱固相萃取，用Luna ODS C18分离柱，甲醇 0．4g／L十六烷基溴化铵的水溶液(70 30)为流动相，荧光检测波长：Ex为554nm，Em为570nm。结果：玫瑰精线性范围为0．05～10．00μg/mL，X^2=0．999，平均回收率为85．92％，RSD=4．63％(n=6)，最低检出限为2μg／kg。结论：该方法灵敏度高，重现性和选择性好，易于操作，是检测染色虾米中碱性玫瑰精含量之有效定量方法。     

离子色谱法测定食品中的甜蜜素和苯甲酸

目的：采用离子交换-电导检测离子色谱法测定食品中的甜蜜素和苯甲酸。方法：选用IonPacAS11-HC分析柱，25．0mmol／L NaOH＋5％甲醇淋洗液，外接水自动再生，样品经沉淀处理，过滤后进样分析。结果：方法的线性范围广、相关性好（r〉0．999），甜蜜素和苯甲酸样品及标准测定的相对标准偏差（RSD）分别为0．2％～4．8％、3．5％、0．1％～7．6％、0．6％，样品加标回收率分别为90．4％～105．1％、92．0％～106．8％，检出限分别为0．48、0．57mg／kg。结论：与国标方法对比测定的结果表明，该方法的准确度高，适用性较好。     

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.     

The risk of heat exhaustion at a deep underground metalliferous mine in relation to surface temperatures

The risk of heat exhaustion at a deep underground metalliferous mine was assessed in relation to thermal conditions prevailing on the surface. For each day of a 1-year prospective case series of heat exhaustion, surface 24-h mean wet and dry bulb temperatures were recorded. From this data, 24-h mean wet bulb globe temperatures were derived using certain assumptions. The three surface temperature variables were significantly higher on those days on which heat exhaustion occurred, compared to those days on which it did not occur (P < 0.001). The relative risk of heat exhaustion on days when the 24-h mean wet bulb globe temperature was in the range 26.0-28.0 degrees C was 4.82 (95% confidence interval 2.12-10.96). Surface temperature data could be used at this mine to warn miners about the risk of heat exhaustion.