ABSTRACT Objectives To compare the discrimination and calibration of six risk scoring systems in the assessment of patients with stroke‐associated pneumonia (SAP) after acute ischemic stroke. Methods The validation cohort was derived from the Third China National Stroke Registry. SAP was diagnosed according to the criteria for hospital‐acquired pneumonia of the Centers for Disease Control and Prevention. The area under the receiver operating characteristic curve (AUROC) and Hosmer‐Lemeshow goodness‐of‐fit test were used to assess discrimination and calibration. Results A total of 12,071 patients were included in the study and 606 (5.02%) patients were diagnosed with in‐hospital SAP after ischemic stroke. The AUROC of the six clinical scores ranged from 0.660 to 0.752. In the pairwise comparison, the AIS‐APS score (0.752, 95% CI = 0.730–0.773, p < 0.001) showed significantly better discrimination than the other risk models, except the PASS score. The AIS‐APS score had the largest Cox and Snell R 2 for in‐hospital SAP after ischemic stroke. In the subgroup analysis, among patients over 61 years of age, all TOAST subtypes except small vessel disease, length of hospital stay longer than 8 days, male and female sex, different groups stratified by admission NIHSS score and time from onset to arrival, the AIS‐APS score showed better discrimination than other risk models with regard to SAP after AIS. Conclusions Our study compared the discrimination and calibration of the Kwon Pneumonia Score, A2DS2 score, PANTHERIS score, AIS‐APS score, ISAN score, and PASS score in SAP identification; of these, the AIS‐APS score showed the best performance.

目的 研发基于稳态视觉诱发电位脑机接口的卒中后语言障碍辅助交流系统,即卒中语言之星系统,以提高卒中后语言障碍患者的生活质量.方法 根据卒中后语言障碍患者的临床特点和应用需求,设计卒中语言之星系统的理论构架.统计18名健康受试者完成指令及打字任务的系统性能指标(如信息传输速率、准确率、识别时长)评估系统可行性,采用美国国家航空航天局任务负荷指数量表评估使用负荷,并分析比较男性与女性受试者的性能评价指标及使用负荷评价指标.结果 卒中语言之星系统包含紧急呼叫、指令与打字三种模式,通过采集受试者枕叶脑电信号,采用空时均衡动态窗算法解码,具有语音播报和屏幕反馈功能.验证结果显示,受试者利用卒中语言之星系统完成打字-单任务平均信息传输速率为79.92±43.55?bits/min,准确率为94.00％(92.00％～97.00％);古诗任务输出速率为1.79(1.49～3.05)字/分钟;指令-单任务输出速率为32.44(11.73～38.64)指令/分钟,正确率为95.65％(90.76％～98.37％);指令-连续性任务输出速率为23.66±9.50指令/分钟.女性受试者打字-单任务中平均信息传输速率、正确率,指令-单任务中输出速率和正确率,指令-连续性任务中输出速率均高于男性受试者,差异均有统计学意义.结论 受试者均能借助所构建系统实现紧急呼叫、指令输出和汉英拼写,该系统有望在临床环境中提升沟通的效率.

Objective:To aim at the present status of lacking of inspection persons and equipments for monitoring water quality in rural water plants,propose a suitable method of fluoride determination in drinking water.Methods: Simplify the process of operation,compare the simple method with national standard method for fluoride determination and research on the precision,accuracy,storage time of standardized reagents and standard curve fitting of the simple method.Results: The results of simple method were consistent with national standard method;RSD was 6.5%;the recovery was 83%~115%;the storage time of standardized reagents was above 9 months;To simplify the standard curve,visual colorimetry and fitting standard curve can be used.Conclusion: This method is simple,fast and accurate,it need not draw standard curve and can determinate water samples directly.The simple method is suitable for water quality laboratory in rural water plants.

BACKGROUNDTrace elements are involved in metabolic processes and oxidation-reduction reactions in the central nervous system and could have a possible effect on cognitive function. The relationship between trace elements measured in individual biological samples and cognitive function in an elderly population had not been investigated extensively.METHODSThe participant population is part of a large cohort study of 2000 rural elderly Chinese persons. Six cognitive assessment tests were used to evaluate cognitive function in this population, and a composite score was created to represent global cognitive function. Trace element levels of aluminum, calcium, cadmium, copper, iron, lead, and zinc were analyzed in plasma samples of 188 individuals who were randomly selected and consented to donating fasting blood. Analysis of covariance models were used to assess the association between each trace element and the composite cognitive score adjusting for demographics, medical history of chronic diseases, and the apolipoprotein E (APOE) genotype.RESULTSThree trace elements-calcium, cadmium, and copper-were found to be significantly related to the composite cognitive score. Increasing plasma calcium level was associated with higher cognitive score (p <.0001). Increasing cadmium and copper, in contrast, were significantly associated with lower composite score (p =.0044 and p =.0121, respectively). Other trace elements did not show significant association with the composite cognitive score.CONCLUSIONSOur results suggest that calcium, cadmium, and copper may be associated with cognitive function in the elderly population.

目的硒是与抗氧化酶的活性有关的微量元素,被认为是一种通过增强酶的活性来拮抗自由基的保护剂。关于硒与阿尔茨海默病（AD=Alzheimer’s Disease,或称Dementia）的关系研究结果不一致。为此,进行了硒水平与中国农村老年人群认知能力研究。方法研究对象为中国四川和山东两省四县市的2000名≥65岁老年人群,当地出生并在当地居住。采用环境流行病学方法,调查研究了老年人群认知能力、APOE基因、指甲硒与血液硒,以及环境食物硒和老年人群日摄硒量。相关系数、方差模型和协方差多因素模型应用于硒水平与认知记分的统计分析。结果分析结果指出硒水平与老年人群认知能力二者之间有明显的正相关,并呈现剂量-反应关系。结论中国农村老年人群稳定的硒暴露水平研究,支持了终身低硒水平与低认知能力相关的假设。

Selenium is a trace element associated with antioxidant activity and is considered to be a protective agent against cognitive decline through the maintenance of better enzyme activities. A baseline survey of 2000 rural Chinese age 65 and over from two provinces in China was conducted from December 2003 to May 2005 using the Community Screening Instrument for Dementia (CSID), CERAD Word List Learning test, a IU Story Recall test, Animal Fluency test, and IU Token test. The overwhelming majority (92.5%) of study participants were born in the same county where they currently reside and have lived there throughout their entire life. Nail samples were collected and analyzed for selenium contents. Blood samples were collected using filter cards to determine genotype for Apolipoprotein E (APOE). In addition, Body Mass Index (BMI) using weight and height measures obtained at the baseline evaluation was obtained. A follow-up evaluation using the same cognitive instruments was conducted two and half years after baseline with 1735 subjects participating in the follow-up evaluation. Analysis of covariance models were used to estimate the association between quintile selenium levels measured in nail samples and decline measured in each cognitive instrument adjusting for age, gender, education, APOE status, history of stroke and baseline BMI. Lower quintile selenium levels measured in nail samples were significantly associated with greater decline on the IU Story Recall score (p< 0.0001) and the CERAD Word List Recall score (p=0.0029). A marginally significant association was seen for the CERAD Word Learning score (p=0.0579). No significant association was found between selenium quintiles and decline on the CSID score (p=0.4562), the Animal Fluency score (p=0.4395) and the IU Token Test (p=0.4459). Our results offer some support to the hypothesis that low selenium level is associated with greater cognitive decline. However, our observed associations seem limited primarily to memory decline. Longer follow-up period is needed to examine selenium's effect on long-term cognitive decline.

OBJECTIVE:To set up a method for simultaneous determination of eight elements in grain and vegetable by microwave digestion-inductively coupled plasma-mass spectrometry (ICP-MS).METHODS:Food samples were digested in a microwave digestion system with nitric acid solution, and contents of Al, As, Cd, Cu, Pb, Zn, Fe and Ca in the digestion solutions were determined simultaneously by ICP-MS.RESULTS:The national standard reference materials such as mussel (GBW08571) and wheat powder (GBW08503B) were applied in the process of sample analysis, and the determination values of the standard reference materials were within the certified values. The accuracy of the method was 79.4%-111.5%, and the RSD was less 1.1%-6.6%. The recoveries of the spiked samples were 93.5%-110%. In order to reduce the matrix interference, the calibration of internal standard and the sample dilution were introduced for ICP-MS.CONCLUSION:This method has simple operation, rapid analysis, high accuracy, and reliable, and can be applied in simultaneous determination of multiple elements in food samples.

Selenium is a trace element associated with antioxidant activity and is considered to be a protective agent against free radicals through enhanced enzyme activity. Studies on selenium and cognitive function or Alzheimer's disease have yielded inconsistent results. A cross-sectional survey of 2,000 rural Chinese aged 65 years or older from two provinces in the People's Republic of China was conducted from December 2003 to May 2005 by use of the Community Screening Instrument for Dementia, the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List Learning Test, the Indiana University Story Recall Test, the Animal Fluency Test, and the Indiana University Token Test. Over 70% of the study participants have lived in the same village since birth. Nail samples were collected and analyzed for selenium contents. Analysis-of-covariance models were used to estimate the association between quintile selenium levels measured in nail samples and cognitive test scores, with adjustment for other covariates. Lower selenium levels measured in nail samples were significantly associated with lower cognitive scores (p < 0.0087 for all tests) except the Animal Fluency Test (p = 0.4378). A dose-response effect of selenium quintiles was also seen for those significant associations. Results in this geographically stable cohort support the hypothesis that a lifelong low selenium level is associated with lower cognitive function.

Selenium is a trace element associated with the activity of the antioxidant enzyme glutathione peroxidase and is considered to be a protective agent against free radicals through enhanced enzyme activity. Associations between low selenium and increased risk in various disease indices including cancer, cardiovascular disease, reproduction and neonatal health, and asthma have been reported. The limited studies on selenium and cognitive function or Alzheimer's disease, however, have not reached unequivocal conclusions. To examine the association between selenium levels and cognitive function in the elderly. A cross–sectional survey of 2000 rural Chinese age 65 and over from two provinces in China was conducted using the Community Screening Instrument for Dementia, CERAD Word List Learning test, a 14–item story recall, Animal Fluency test, and IU Token Test. Over seventy percent of study participants have lived in the same village since birth. Nail samples were collected and analyzed for selenium contents. Food frequency questionnaires were administrated while local food samples were collected and analyzed for selenium content. APOE genotype was determined using blood samples collected on filter cards. Analysis of covariance models were used to estimate the association between selenium levels measured in nail samples and from food intake and cognitive test scores adjusted for age, gender, education and APOE genotype. Lower selenium levels measured in nail samples and from food intake were significantly associated with poor cognitive function as measured by various cognitive tests. Standardized beta coefficients range from 0.06 to 0.24 on all tests (p<0.01 for all) adjusted for age, gender, education level and APOE genotype. The APO ϵ4 allele was not significantly associated with any cognitive measures and there is no significant interaction between APOE and selenium levels. Our results support the hypothesis that low selenium level is associated with poor cognitive function. Longitudinal follow–up of this cohort will help to establish whether selenium levels affect the rate of cognitive decline associated with aging.

目的:建立了用微波消解技术进行样品前处理,磷钼蓝分光光度法测定食品中磷含量的方法.方法:使用微波消解炉,在食品中加入硝酸密闭消解,消解液用磷钼蓝分光光度法在 660 nm 波长处测定样品中磷的含量.结果:微波消解技术可将样品消解完全,采用磷钼蓝分光光度法测定体系中磷的含量在 0～60 μg 时,磷的含量与吸光度呈线性关系,相关系数为0.9998;用本法测定了国家标准参考物质小麦粉(GBW08503)和贻贝(GBW08571),测定值与标准参考值相吻合,相对标准偏差分别为 0.8% 和 2.2%, 对实际样品的加标平均回收率在 94.9%～109% 之间.结论:该法操作简单、试剂用量少、重现性好,用微波消解技术大大缩短了样品前处理的时间,适于食品中磷元素含量的测定.

The relationship between trace element levels in drinking water and cognitive function was studied for elderly residents in rural areas in China. Cognitive function was measured by a Chinese translation of the Community Screening Interview for Dementia (CSI "D"). The trace elements fluoride, calcium, selenium, aluminum, iron, zinc, cadmium, lead and arsenic contents of drinking water were determined using Chinese. National Standard Methods. A mixed effects model was used to evaluate the effect of each of the elements on cognitive function while adjusting for age, sex, and education level. Several of the elements examined had a significant effect on cognitive function when they were examined in a univariate context. However, after adjusting for other elements many of these results were not significant. There was a significant quadratic effect for calcium and a significant zinc-cadmium interaction. Cognitive function increased with calcium level to a certain point, and then decreased as calcium continued to increase. Zinc showed a positive relationship with cognitive function at low cadmium levels, but a negative relationship at high cadmium levels.

A simple method of determining arsenic in blood by electrothermal atomic absorption spectrophotometer was developed based on the modification of the method of extraction with acid. A Ni(NO3)2 matrix modifier was used to thermally stabilize arsenic. After comparing to the wet-digestion method, the result suggests that this method is relatively simple, accurate, precise and sensitive. The detection limit is 3.03 ng/mL, the precision is 2.5% and the recovery in the range of 88.0%～98.1%. The concentration of arsenic in blood was determined by this method. The results show that the concentration of arsenic in blood of the arsenism mice is higher than that in the control mice.

Recently a huge amount of fluoride in coal has been released into indoor environments by the combustion of coal and fluoride pollution seems to be increasing in some rural areas in China. Combustion of coal and coal bricks is the primary source of gaseous and aerosol fluoride and these forms of fluoride can easily enter exposed food products and the human respiratory tract. Major human fluoride exposure was caused by consumption of fluoride contaminated food, such as corn, chilies and potatoes. For each diagnostic syndrome of dental fluorosis, a log-normal distribution was observed on the logarithm of urinary fluoride concentration in students in China. Urinary fluoride content was found to be a primary health indicator of the prevalence of dental fluorosis in the community. In the fluorosis areas, osteosclerosis in skeletal fluorosis patients was observed with a high prevalence. A biochemical marker of bone resorption, urinary deoxypyridinoline content was much higher in residents in China than in residents in Japan. It was suggested that bone resorption was stimulated to a greater extent in residents in China and fluoride may stimulate both bone resorption and bone formation. Renal function especially glomerular filtration rate was very sensitive to fluoride exposure. Inorganic phosphate concentrations in urine were significantly lower in the residents in fluorosis areas in China than in non-fluorosis area in China and Japan. Since airborne fluoride from the combustion of coal pollutes extensively both the living environment and food, it is necessary to reduce fluoride pollution caused by coal burning.

There are contradictory reports on the prevalence of bone fractures associated with long-term fluoride exposure from drinking water. The prevalence of bone fracture in six rural areas of China and the exposure of fluoride in drinking water was investigated. The data including medical history and demographic information, bone fractures, fluoride content in drinking water, physical activity, cigarette smoking, alcohol consumption and dietary intakes were collected. A retrospective epidemiological study by using the same design, method, quality control and the same questionnaire was conducted. A total of 8266 male and female over 50 years of age were divided into 6 groups by the fluoride concentrations in drinking water. The subjects in each group exposed to different levels of fluoride (0.25-0.34, 0.58-0.73, 1.00-1.06, 1.45-2.19, 2.62-3.58 and 4.32-7.97 mg/L) were 1363, 1407, 1370, 1574, 1051 and 1501 respectively. It has been confirmed that drinking water was the only major source of fluoride exposure in the studied populations. The total bone fracture rates were 7.41%, 6.40%, 5.11%, 6.04%, 6.09% and 7.40% in each group. Natural bone fracture rates in each group were 3.01%, 2.21%, 1.31%, 1.65%, 1.43% and 3.66% respectively. The prevalence of bone fracture and water fluoride level appeared a U-shaped relationship. The prevalence of total bone fracture and natural bone fracture in the population with fluoride 1.00-1.06 mg/L in drinking water was the lowest, compared with the groups exposed to fluoride higher than 4.32 mg/L and lower than 0.73 mg/L. The highest prevalence of hip fracture was in the group with higher water fluoride (4.32-7.97 mg/L) exposure. In general, the prevalence of hip fracture was lower and stable up to 1.06 mg/L of fluoride in drinking water, and then it appeared to rise. Based on the data collected in this investigation, it is concluded that the long-term fluoride exposure from drinking water higher than 4.32 mg/L might increase the risk of overall fractures as well as hip fractures. The risk of overall fractures and natural fractures might be lower while the water fluoride level is at 1.00-1.06 mg/L, however, no protective benefits of fluoride for the risk of hip fracture was observed.

Findings on the risk of bone fractures associated with long-term fluoride exposure from drinking water have been contradictory. The purpose of this study was to determine the prevalence of bone fracture, including hip fracture, in six Chinese populations with water fluoride concentrations ranging from 0.25 to 7.97 parts per million (ppm). A total of 8266 male and female subjects > or =50 years of age were enrolled. Parameters evaluated included fluoride exposure, prevalence of bone fractures, demographics, medical history, physical activity, cigarette smoking, and alcohol consumption. The results confirmed that drinking water was the only major source of fluoride exposure in the study populations. A U-shaped pattern was detected for the relationship between the prevalence of bone fracture and water fluoride level. The prevalence of overall bone fracture was lowest in the population of 1.00-1.06 ppm fluoride in drinking water, which was significantly lower (p < 0.05) than that of the groups exposed to water fluoride levels > or =4.32 and < or =0.34 ppm. The prevalence of hip fractures was highest in the group with the highest water fluoride (4.32-7.97 ppm). The value is significantly higher than the population with 1.00-1.06 ppm water fluoride, which had the lowest prevalence rate. It is concluded that long-term fluoride exposure from drinking water containing > or =4.32 ppm increases the risk of overall fractures as well as hip fractures. Water fluoride levels at 1.00-1.06 ppm decrease the risk of overall fractures relative to negligible fluoride in water; however, there does not appear to be similar protective benefits for the risk of hip fractures.

The effects of airborne fluoride from unvented indoor burning of fluoride-rich coal on the bones and teeth of residents of two rural villages in SW China were investigated and compared. In the highly polluted village of Xaochang in Sichuan Province, stage HI skeletal fluorosis was found in 43 (84%) of 51 examinees. In the moderately polluted village of Minzhu in Guizhu Province, this stage was seen in 25 (51%) of 49 examinees. In the nonpolluted control village of Shucai in Jiangxi Province in SE China, none of 47 examinees showed any evidence of skeletal fluorosis. In Minzhu, but not in Xaochang, significantly more males than females were afflicted with stage III skeletal fluorosis. In contrast with Xaochang, some examinees in Minzhu had serious skeletal effects but normal teeth or minor dental fluorosis, A high frequency of extremital transverse bone growth lines was observed in Xaochang but not in Minzhu, These findings suggest that greater exposure to fluoride occurred during infancy and early childhood in Xaochang than in Minzhu.

The relation between trace element levels in drinking water and cognitive function was investigated in a population-based study of elderly residents (n = 1,016) in rural China in 1996-1997. Cognitive function was measured using a Chinese translation of the Community Screening Interview for Dementia. A mixed effects model was used to evaluate the effect of each of the elements on cognitive function while adjusting for age, sex, and educational level. Several of the elements examined had a significant effect on cognitive function when they were assessed in a univariate context. However, after adjustment for other elements, many of these results were not significant. There was a significant quadratic effect for calcium and a significant zinc-cadmium interaction. Cognitive function increased with calcium level up to a certain point and then decreased as calcium continued to increase. Zinc showed a positive relation with cognitive function at low cadmium levels but a negative relation at high levels.