载镧改性沸石对高氟水除氟效果的研究

目的研究载镧改性沸石对高氟水除氟的效果。方法用0.5mol/L的NaOH溶液浸泡活化沸石2h,以固液比1:5加入150g/L氯化镧溶液,以氨水调节pH值为11～12,浸渍振荡24h,干燥后于400～500℃焙烧3～4h。采用载镧改性沸石对10mg/L含氟水样进行静态除氟实验(适宜条件为:载镧改性沸石用量为3g/L时,pH值为4～5,140r/min振荡速度下于室温吸附200min)和动态除氟实验(适宜条件为:载镧改性沸石用量为1.33g/L,pH值为4～5,室温下以4～5ml/min的流速通过吸附柱)。并拟合Langmuir吸附等温线。结果静态除氟的除氟率在90%以上,吸附容量为3.24mg/g;动态除氟的吸附容量为7.67mg/g。拟合Langmuir吸附等温线所得方程为y=0.1334x+0.0181,相关系数达到0.9974,饱和吸附量(q∞)为7.50mg/g,吸附平衡常数(KL)为7.37L/mg。结论载镧改性沸石对高氟水除氟容量大,除氟效率高。     

锆改性壳聚糖-沸石-高岭土复合吸附剂的制备及饮水除氟应用

目的研制锆改性壳聚糖-沸石-高岭土复合吸附剂用于除去水中的氟离子。方法取0.60 g壳聚糖溶于36 ml的5%乙酸溶液,加入0.15 mol/L氧氯化锆溶液20.00 ml,用5%氨水调至p H 5.0,搅拌反应60 min,加入1.40 g人造沸石和0.50 g高岭土继续搅拌60 min,再用5%氨水调至p H 7.5,析出锆-壳聚糖-沸石-高岭土复合吸附剂,分别对5.24 mg/L含氟水进行静态除氟实验[复合吸附剂用量为1.5 g/L,p H 4~7(p H 5~6最佳),158 r/min振荡速度下于室温吸附120 min]和动态除氟实验[复合吸附剂2.00 g,p H 5~6(p H 6最佳),吸附剂粒径1~2 mm,水样以3~4 ml/min通过吸附柱]。结果静态除氟实验结果显示,复合吸附剂对氟的平衡吸附量为3.07 mg/g,出水氟浓度小于1.0 mg/L;动态除氟实验结果显示,过水量为1 800 ml,复合吸附剂对氟的吸附容量为2.71 mg/g。实验数据(30℃)符合Langmuir吸附等温线,最大吸附量为15.53mg/g。结论锆改性壳聚糖-沸石-高岭土复合吸附剂处理水样不会造成二次污染,用于静态除氟和动态除氟均可获得满意的效果。     

载锆改性沸石对水中氟的吸附性能及动态除氟效果

[目的]对沸石进行负载锆的改性,用于高氟水除氟,评价其除氟效果。[方法]用0.5mol/L的盐酸活化,10%氧氯化锆溶液对人造沸石进行改性,用模拟高氟水样进行静态吸附和动态除氟实验。[结果]动力学研究结果表明:吸附速度快,150min达到吸附平衡,吸附速率可用拟二级动力学方程描述。平衡吸附数据符合Langmuir吸附等温线,饱和吸附量为6.96mg/g,吸附平衡常数为0.548L/mg。动态除氟在pH5～7范围均有较好的除氟效果,穿透点前(出水氟浓度﹤1.0mg/L)的除氟容量在1.2～2.2mg/g,在pH=5时除氟最佳。水质硬度对动态除氟的影响不大。[结论]载锆改性沸石除氟容量大,除氟后的水质满足国家饮用水卫生标准对氟的要求(氟浓度﹤1.0mg/L)。     

锆改性壳聚糖制备的优化及饮水除氟效果

目的研制锆改性壳聚糖吸附剂用于除去水中的氟离子。方法取1.00 g壳聚糖,溶于60 ml的5%乙酸溶液,按锆与壳聚糖质量比为3∶20加入氧氯化锆溶液,搅拌反应60 min,然后滴加25%~28%氨水使改性壳聚糖完全析出,过滤、洗涤、70℃烘干,制得锆改性壳聚糖吸附剂。采用该吸附剂对8.95 mg/L含氟水样进行静态除氟实验(适宜条件为:pH 3~9,140 r/min振荡速度下于室温吸附120 min)。并拟合Langmuir吸附等温线和二级动力学方程。结果吸附剂用量为1.0 g/L时,除氟率在90.7%,平衡吸附量为8.12 mg/g。拟合Langmuir吸附等温线(30℃)方程的R2=0.999 4,最大吸附量为12.30 mg/g,吸附平衡常数为1.58 L/mg。拟合二级动力学方程的R2值为1。结论锆改性壳聚糖对高氟水吸附容量大,除氟效率高。     

氧化镧改性沸石对水中氟的静态吸附性能评价

[目的]对沸石进行负载氧化镧的改性,用于高氟水除氟,评价其吸附性能。[方法]用碱性氯化镧溶液浸渍—干燥—高温焙烧法对人造沸石进行改性,用模拟高氟水样进行静态吸附实验。[结果]动力学研究结果表明:吸附速度快,40min内接近吸附平衡,吸附速率可用拟二级动力学方程描述。吸附等温线表明:在平衡浓度很低(﹤1.0mg/L)时就接近饱和吸附量,平衡吸附数据符合Langmuir吸附等温线,饱和吸附量为7.49mg/g,吸附平衡常数为7.38L/mg。对浓度为10mg/L的含氟水样投加3g/L吸附剂,除氟率达91.4%。溶液pH值对吸附有影响,最佳吸附在pH4～5。水中共存CaCl2及温度对吸附的影响不大。[结论]氧化镧改性沸石对氟的吸附力强,除氟效率高。     

天然沸石处理高氟地下水的实验研究

目的 研究天然沸石的改性活化工艺及其作为除氟剂在高氟地下水处理中的初步应用.方法 参照GB/T7484-1987《水质氟化物的测定离子选择电极法》检测氟离子浓度.研究沸石的活化处理流程中,盐酸和硫酸铝钾溶液活化的最佳除氟浓度、时间,高温焙烧活化的最佳除氟温度、时间,以及沸石的最佳除氟用量.采用活化的沸石对模拟水样进行静态和动态除氟实验,并对地下井水水样进行除氟实验,参照《生活饮用水卫生规范》(2001)对除氟前、后水样进行检测和评价.采用不同浓度硫酸铝钾溶液对经除氟实验后的沸石进行再生,并用再生沸石对模拟水样进行除氟实验.结果 沸石经5.0mol/L盐酸活化处理5 h后,洗至中性、烘干;然后用0.3mol/L硫酸铝钾溶液活化处理10 h,洗净、烘干;最后经300℃高温焙烧活化4h后,当固、液比为1∶20时除氟效果达到最佳.当模拟水样氟离子浓度为1 mg/L时,经过1次处理即可达标;当氟离子浓度为5、10 mg/L时,采取2次及以上循环吸附才可达标.经活化沸石处理40 min内的模拟水样可达标,最高除氟率达94%.高氟地下水样除氟后达标.2.0%硫酸铝钾溶液再生的沸石除氟率最高(45.0%).结论 天然沸石经过改性活化后具有较好的除氟效果,可以再生利用,成本较低,而且对水质没有较大影响,可以作为高氟地区的饮用水除氟剂.     

镧改性壳聚糖制备的优化及饮水除氟效果

目的研究镧改性壳聚糖去除水中氟离子的性能。方法取1.00 g壳聚糖,溶于60 ml 5%乙酸溶液,按镧与壳聚糖质量比为1∶10加入硝酸镧溶液,用5%氨水调节至p H 5.0~6.0,搅拌反应60 min,然后滴加25%氨水使改性壳聚糖完全析出,过滤,洗涤,70℃烘干,制得镧改性壳聚糖吸附剂。采用该吸附剂对8.95 mg/L含氟水样进行静态除氟实验(适宜条件为:p H 4~8,140 r/min振荡速度下于室温吸附150 min)。并拟合Langmuir吸附等温线和二级动力学方程。结果吸附剂用量为0.4 g/L时,除氟率在90.9%,平衡吸附量为20.23 mg/g。拟合Langmuir吸附等温线(30℃)方程的R2=0.996,最大吸附量为25.64 mg/g,吸附平衡常数为1.77 L/mg。拟合二级动力学方程的R2值为1。结论镧改性壳聚糖对高氟水吸附容量大,除氟效率高。     

牙斑和唾液中的氟化物浓度

牙斑氟浓度与牙斑钙浓度是直接相关的。尝试通过用洁牙剂或冲洗的方法以增加斑钙,进而增加斑氟的摄入,但存在不一致的结果。以双盲的、双交叉研究,用150mmol/L乳酸钙冲洗,再用安慰剂或氟洁牙剂(1030μg/g,氟化钠)刷牙,检测牙斑和唾液中的氟和钙。16名儿童(8～10岁),根据处理的情况(安慰剂洁牙剂组、含氟洁牙剂组、事先用乳酸钙或除离子水冲洗)被随机分成4个不同的组。开始使用洁牙剂7d刷牙后1h和12h采集牙斑和唾液。用电极测定氟,用原子吸收分光术测定钙。除用安慰剂洁牙剂刷牙后1h的牙斑钙之外,在用乳酸钙冲洗后,牙斑和唾液中的钙无显著增加。唾液中的氟显著增加与含氟洁牙剂使用后1h用乳酸钙冲洗有关。在任何条件下,乳酸钙冲洗对牙斑氟无明显作用。     

滤膜采样离子选择性电极法测定氟化物电极斜率偏低原因及改进方法

氟离子选择性电极用于分析空气中氟化物已被普遍使用,但是采样方法与分析方法仍在不断改进与发展。原方法氟化物气体和含氟粉尘分别采用吸收液和滤膜采样,现行方法改用浸渍过的滤膜采集空气中的气态氟及含氟烟尘,以15 L/min的速度抽取75 L空气,具有采样时间短、富集量大、采样方便、     

改性石英砂及沸石滤料除氟性能比较研究

研究了以石英砂和沸石为骨架的吸附材料经铝盐改性处理后在处理饮用水中过量氟的处理行为，比较两种改性滤料处理能力的不同并对差异进行分析。实验表明物理空间结构性强的沸石作为改性滤料的应用有着独到的优越性，除氟效率达到98％以上。     

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.     

Worker education in the primary prevention of occupational dermatoses

This paper reports the evaluation of a skin care education programmeconducted on a fine chemicals manufacturing site where over1,000 employees are located. Approximately 60% are involvedin chemical manufacture. Over a 12 month period production staffreceived training in prevention of occupational dermatoses linkedto a site-wide poster initiative. The incidence of new casesof occupational dermatoses fell from 0.055 (70 cases in 1,277employees) to 0.021 (27 cases in 1,277 employees) before andafter the intervention respectively (p<0.0001). After otherfactors such as chemicals handled, observer bias and changesin reporting related to socioeconomic climate were taken intoaccount it is concluded that this study demonstrates the importanceof worker education as a tool for primary prevention of disease.Training materials such as video and poster presentations maybe effectively used in the chemical manufacturing industry asan adjunct to prevention and control of exposure to substanceshazardous to the skin. Such methods may also be used in otherindustries where there are significant risks of dermatoses.     

Regional Variation in Travel-related Illness acquired in Africa,March 1997–May 2011

To understand geographic variation in travel-related illness acquired in distinct African regions, we used the GeoSentinel Surveillance Network database to analyze records for 16,893 ill travelers returning from Africa over a 14-year period. Travelers to northern Africa most commonly reported gastrointestinal illnesses and dog bites. Febrile illnesses were more common in travelers returning from sub-Saharan countries. Eleven travelers died, 9 of malaria; these deaths occurred mainly among male business travelers to sub-Saharan Africa. The profile of illness varied substantially by region: malaria predominated in travelers returning from Central and Western Africa; schistosomiasis, strongyloidiasis, and dengue from Eastern and Western Africa; and loaisis from Central Africa. There were few reports of vaccine-preventable infections, HIV infection, and tuberculosis. Geographic profiling of illness acquired during travel to Africa guides targeted pretravel advice, expedites diagnosis in ill returning travelers, and may influence destination choices in tourism.     

The design of hazard risk assessment matrices for ranking occupational health risks and their application in mining and minerals processing

Two hazard risk assessment matrices for the ranking of occupational health risks are described. The qualitative matrix uses qualitative measures of probability and consequence to determine risk assessment codes for hazard-disease combinations. A walk-through survey of an underground metalliferous mine and concentrator is used to demonstrate how the qualitative matrix can be applied to determine priorities for the control of occupational health hazards. The semi-quantitative matrix uses attributable risk as a quantitative measure of probability and uses qualitative measures of consequence. A practical application of this matrix is the determination of occupational health priorities using existing epidemiological studies. Calculated attributable risks from epidemiological studies of hazard-disease combinations in mining and minerals processing are used as examples. These historic response data do not reflect the risks associated with current exposures. A method using current exposure data, known exposure-response relationships and the semi-quantitative matrix is proposed for more accurate and current risk rankings.     

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.