A scripted activity study of the impact of protective advice on personal exposure to ultra-fine and fine particulate matter and volatile organic compounds

We evaluated the impact on personal exposure to air pollutants of following advice which typically accompanies air quality advisories and indices. Scripts prescribed the time, location, duration and nature of activities intended to simulate daily activity patterns for adults and children. Scripts were paired such that one individual would proceed with usual activities (base scenario), whereas the other (intervention scenario) would alter activities as if following advice. Other than commuting, where the intervention group walked or used public transportation rather than riding in personal vehicles, this group generally spent less time outdoors. Ultra-fine particles (UFPs), particulate matter of median aerodynamic diameter less than 2.5 mum (PM(2.5)) and total volatile organic compounds (VOCs) were measured using samplers carried by individuals during the course of daily activities. During daytime activities (e.g., work, daycare) constituting the largest share of sampling time (approximately 6 h per day), the intervention group experienced a 14% reduction in exposure to UFPs (P=0.01), a 21% reduction in exposure to PM(2.5) (P=0.08), and an 86% increase in exposure to VOCs (P=0.02). Other findings included an 89% increase in exposure to UFPs (P=0.02) and a threefold increase in exposure to VOCs (P=0.08) in the intervention group during evening cooking. Following smog advisory advice results in reduced exposures to some pollutants, while at the same time increasing exposure to others. Advice needs to be refined giving consideration to overall personal exposure.     

Chronic exposure to fine particles and mortality: an extended follow-up of the Harvard Six Cities study from 1974 to 2009

Background: Epidemiologic studies have reported associations between fine particles (aerodynamic diameter ≤ 2.5 µm; PM_2.5) and mortality. However, concerns have been raised regarding the sensitivity of the results to model specifications, lower exposures, and averaging time.Objective: We addressed these issues using 11 additional years of follow-up of the Harvard Six Cities study, incorporating recent lower exposures.Methods: We replicated the previously applied Cox regression, and examined different time lags, the shape of the concentration–response relationship using penalized splines, and changes in the slope of the relation over time. We then conducted Poisson survival analysis with time-varying effects for smoking, sex, and education.Results: Since 2001, average PM_2.5 levels, for all six cities, were < 18 µg/m³. Each increase in PM_2.5 (10 µg/m³) was associated with an adjusted increased risk of all-cause mortality (PM_2.5 average on previous year) of 14% [95% confidence interval (CI): 7, 22], and with 26% (95% CI: 14, 40) and 37% (95% CI: 7, 75) increases in cardiovascular and lung-cancer mortality (PM_2.5 average of three previous years), respectively. The concentration–response relationship was linear down to PM_2.5 concentrations of 8 µg/m³. Mortality rate ratios for PM_2.5 fluctuated over time, but without clear trends despite a substantial drop in the sulfate fraction. Poisson models produced similar results.Conclusions: These results suggest that further public policy efforts that reduce fine particulate matter air pollution are likely to have continuing public health benefits.     

A comparative field study on dust measurements by different sampling methods with emphasis on estimating factors for recalculation from chinese 'total dust' measurements to respirable dust concentrations

In China, dust samplers were originally designed to collect 'total dust' for a short term during production, which is different from the widely adopted sampling strategy for dust. With the aim to provide the conversion factor from Chinese total dust to US and German respirable dust and to look at the influences on conversion factors from environment, production, and instruments, a comparative field study on the dust concentration measurements by different sampling methods was carried out in the same Chinese industries as in the 1989-1990 study and in some other factories. A supplemental experiment was also conducted in a wind tunnel. Dust concentration was measured with a parallel sampling strategy by using the following samplers: 10-mm nylon cyclone for US respirable dust (AR), FSP-Berufsgenossenschaftliches Institut für Arbeitssicherheit (BIA) cyclone for German respirable dust (GR), and samplers for Chinese total dust (CT). Totally, 1434 samples were collected (269 AR, 198 GR, and 967 CT), from which 429 matched sample pairs (249 pairs of AR/CT, 180 GR/CT) were available to calculate conversion ratios. Industry- and job-based conversion factors are presented in this study. The conversion factor of AR/CT was 0.38 for tungsten mines, 0.19 for copper/iron mines, 0.65 for tin mines, and 0.20 for pottery industry, while the factor of GR/CT was 0.69 for tungsten, 0.37 for copper/iron, and 0.52 for pottery. In the job category, AR/CT factors varied from 0.16 to 0.96 and GR/CT from 0.12 to 0.72. For the industries studied in 1988-1989, the AR/CT and GR/CT factors were 0.29 and 0.45, respectively. Both factors were definitely influenced by production, CT dust concentration, sample gain, and variation of dust concentration. Moreover, the respirable dust concentration by FSP-BIA was significantly higher than that by 10-mm cyclones, 63.27-73.10% more as showed also by the wind tunnel experiment. Meanwhile, the GR/CT ratio was significantly larger than the AR/CT in every industry or job with only few exceptions. The GR/CT estimates should be considered as independent ones. Following these results, there is a need to use 'ideal samplers' (consistent with the internationally accepted respirable fraction) in practice and to assess the existent samplers in order to homogenize the exposure data situation.     

Effects of fine and ultrafine particles on cardiorespiratory symptoms in elderly subjects with coronary heart disease: the ULTRA study

The ULTRA Study, a study investigating the association between fine and ultrafine particulate air pollution and cardiorespiratory health, was conducted during the winter of 1998-1999 in Amsterdam, the Netherlands; Erfurt, Germany; and Helsinki, Finland. At each study center, a panel of elderly subjects with coronary heart disease recorded cardiac and respiratory symptoms in a diary. Exposure to ambient air pollution was characterized by measuring daily mass concentrations of particles smaller than 10 micro m (PM(10)) and 2.5 micro m (PM(2.5)), number concentrations of ultrafine particles (NC(0.01-0.1)), and gases. Odds ratios for the relation of symptoms to air pollution, adjusted for time trend, respiratory infections, and meteorologic variables, were mostly homogeneous across the centers. No association was found between air pollution and chest pain. A 10- micro g/m(3) increase in PM(2.5) was positively associated with the incidence of shortness of breath (odds ratio (OR) = 1.12, 95% confidence interval (CI): 1.02, 1.24) and with avoidance of activities (OR = 1.09, 95% CI: 0.97, 1.22). NC(0.01-0.1) was only associated with the prevalence of avoidance of activities (OR = 1.10, 95% CI: 1.01, 1.19). In conclusion, PM(2.5) was associated with some cardiac symptoms in three panels of elderly subjects. PM(2.5 )was more strongly related to cardiorespiratory symptoms than ultrafine particles were.     

基于Fisher线性判别分析对乳腺微钙化性质的预测研究

目的:使用基于机器学习的Fisher线性分类判别方法,对分割的乳腺微钙化数据进行线性变换,预测乳腺微钙化的性质.方法:基于Fisher线性分类判别分析原理,建立预测判别模型对乳腺微钙化的良、恶性进行分类.选取在医院行乳腺癌筛查的432例患者的原始数据,将原始数据中的30项569条乳腺癌特征数据为输入变量,以乳腺微钙化良...     

Effect of storage temperature on the activity of submitochondrial particles

The submitochondrial particle (SMP) assay employs processed mammalian mitchondria to assess the toxicity of chemical contaminants in aqueous solutions. Particles and associated reagents are commercially available to support two individual procedures, the electron transfer (ETr) and reverse electron transfer (RET) assays. The objective of the present study was to assess the effect of storage temperature on SMP activity. One RET and one ETr assay were conducted with sodium dodecylsulfate on each of two vials of particles stored at -20 and -80 degrees C at periodic intervals over a six-month span. Results demonstrated that SMP could remain active in either assay through six months of storage at either temperature. However, there were isolated vials of particles stored at -20 degrees C that exhibited unacceptable reductions in activity for both the ETr and the RET assays that were not related to storage duration. These results were used to develop guidance in assessing the acceptability of particle activity in SMP assays.     

A study on fine motor skills of Iranian children with attention deficit/hyper activity disorder aged from 6 to 11 years

The aim of this study was to compare the fine motor skills of two groups of Iranian children. Of the 55 male Tehranian children aged 6 to 10 years, 29 children were typically developing and 26 were identified as attention deficit hyperactivity disorder (ADHD) using the Diagnostic and Statistical Manual of Mental Disorder. All children were assessed using the Raven Intelligence Test and nine fine motor tasks. There were no significant differences between the groups based on intelligence. In eight of the fine motor tasks, there was a significant difference between the groups. These tasks were cutting, placing dots in a grid pattern without direction, threading beads, drawing a line within 1 and 2 minutes, finger movements and Purdue pegboard. Boys who have been identified as ADHD have poorer fine motor skills compared to typically developing boys of the same age. Children aged 6 to 10 years who have been identified as ADHD will require more attention to their fine motor skill performance to enable greater participation in daily living tasks in Tehran such as writing, fine arts and dressing which require fast and quick hand motor skills. There are still limitations in this area; therefore, research in fine motor skills and ADHD children are recommended for future research.     

Airborne concentrations of PM(2.5) and diesel exhaust particles on Harlem sidewalks: a community-based pilot study

Residents of the dense urban core neighborhoods of New York City (NYC) have expressed increasing concern about the potential human health impacts of diesel vehicle emissions. We measured concentrations of particulate matter [less than/equal to] 2.5 micro in aerodynamic diameter (PM(2.5)) and diesel exhaust particles (DEP) on sidewalks in Harlem, NYC, and tested whether spatial variations in concentrations were related to local diesel traffic density. Eight-hour (1000-1800 hr) air samples for PM(2.5 )and elemental carbon (EC) were collected for 5 days in July 1996 on sidewalks adjacent to four geographically distinct Harlem intersections. Samples were taken using portable monitors worn by study staff. Simultaneous traffic counts for diesel trucks, buses, cars, and pedestrians were carried out at each intersection on [Greater/equal to] 2 of the 5 sampling days. Eight-hour diesel vehicle counts ranged from 61 to 2,467 across the four sites. Mean concentrations of PM(2.5) exhibited only modest site-to-site variation (37-47 microg/m(3)), reflecting the importance of broader regional sources of PM(2.5). In contrast, EC concentrations varied 4-fold across sites (from 1.5 to 6 microg/m(3)), and were associated with bus and truck counts on adjacent streets and, at one site, with the presence of a bus depot. A high correlation (r = 0.95) was observed between EC concentrations measured analytically and a blackness measurement based on PM(2.5) filter reflectance, suggesting the utility of the latter as a surrogate measure of DEP in future community-based studies. These results show that local diesel sources in Harlem create spatial variations in sidewalk concentrations of DEP. The study also demonstrates the feasibility of a new paradigm for community-based research involving full and active partnership between academic scientists and community-based organizations.     

上海市居民区大气细颗粒物污染水平及时空分布特征研究

目的观察上海市居民区大气细颗粒物污染水平及时空变化趋势,同时,了解机动车尾气污染对居民区大气细颗粒物污染状况的影响。方法选取上海市区内A、B两个居民区,A居民区为普通居住区,B居民区为交通繁忙区。在交通主干道侧向距离0、50、100和200m设4个监测点,于2010年4月、7月和10月及2011年1月使用AM510细颗粒物监测仪对两个居民区的大气细颗粒物污染水平进行监测,每个月份连续监测10天。每天7:30～10:30同步监测,分析同一居民区大气细颗粒物浓度随道路侧向距离的变化,并比较A,B两个小区大气细颗粒物污染水平。结果上海市大气细颗粒物污染水平的季节变化为:春季>冬季>秋季>夏季。细颗粒物浓度的日变化趋势都呈双峰型,一个峰在上午8:00,另一个峰在晚间19:00,与居民上下班高峰呈一致性。随距离交通主干道侧向距离的增加,居民区内细颗粒物水平呈降低趋势。交通状况不同的居民区细颗粒物污染有明显差异,B居民区由于地处交通繁忙区,大气细颗粒物污染水平也较高。结论上海市居民区大气细颗粒物污染处于较高水平,机动车尾气污染对细颗粒物污染有明显影响。     

Formulas developed based on the ratio of urea nitrogen to creatinine concentrations obtained from multiple spot urine samples are acceptable to predict protein intake at group level but not at individual level

In this study, we hypothesized that spot urine can be used to predict protein intake at both group and individual levels. Participants (n = 369) of this study were recruited from all 47 prefectures in Japan. Sex-specific formulas were developed based on the ratio of urea nitrogen to creatinine concentration obtained from 3 spot urine samples. Validity of the formulas was examined against two 24-hour urine collections for 7 combinations of spot urine (single and means of 2 or 3 samples) using t test (mean estimation), Spearman correlation, and Bland-Altman plot (individual bias). Means of measured protein intake based on 24-hour urinary excretions were 87.3 g/d (standard deviation 19.7) for men and 70.5 g/d (standard deviation 14.7) for women. Irrespective of sex, the predicted intakes were not significantly different (within 2.7% of differences) from those measured by urinary excretions. Predicted intakes were moderately correlated with measured intakes (men, 0.45-0.60; women, 0.35-0.53). Even after using the mean of 3 samples, Bland-Altman plots showed a considerably wide limit of agreement (men, −30 to 33 g/d; women, −27 to 24 g/d). Except for using single spot urine samples in women, the formula tended to overestimate intake at a lower and underestimate at a higher level of protein intake (slope: men, −0.47 [P < .0001]; women, −0.38 [P = .002]). In conclusion, predictive formulas developed in this study can be used to predict protein intake at group level or to rank individuals' intake but not to predict absolute intake at individual level.     

The effect of lung deposition patterns on the activity estimate obtained from a large area germanium detector lung counter.

Lung counters for in vivo detection of low energy photon emitters are typically calibrated using phantoms containing lung tissue equivalent material with the radioactivity homogeneously distributed throughout the material. If the activity in a measurement subject is heterogeneously distributed, the activity estimate for that subject will be uncertain due to the assumptions of distribution. The magnitude of the uncertainty for a four-detector germanium array, using the Lawrence Livermore National Laboratory torso phantom with a newly designed lung set that allows the activity to be localized in one or more of 16 areas, was estimated. The results show that detector arrays will reduce the uncertainties arising from the geometry of the lung deposition compared to single detectors. The estimated activity of an internal deposition that emits 17.5 keV photons can be overestimated by a factor of three, or underestimated by a factor of infinity (i.e., the activity is missed completely). As the photon energy rises to 59.5 keV the uncertainty in the activity decreases so that the maximum overestimate (underestimate) will be a factor of two (five). As the energy rises to 344.3 keV only the maximum underestimate changes: it becomes a factor of three.     

雾霾对高校学生主要活动场所空气微生物浓度的影响

了解雾霾对校园环境空气中微生物分布的影响,为校园环境卫生治理、疾病防控及个人防护提供实验数据.方法 抽取河北大学医学部室外(医苑广场、医苑路、操场)和室内(食堂、教室、学生宿舍)等6个人员主要活动场所,在无雾霾、轻度雾霾、中度雾霾及重度雾霾天气状况下按自然沉降法分别采样,测定空气中细菌和霉菌菌落总数.结果 中度和重度雾霾天气时室外空气中细菌、霉菌菌落总数均高于室内(P值均<0.05). 室外各采样点细菌、霉菌总数均随雾霾程度加重而升高,其中医苑路升高最为显著(P值均<0.05);室内各采样点除学生宿舍内细菌、霉菌浓度在重度雾霾天高于其他天气状况外,食堂、教室随天气变化不明显(P值均>0.05).结论 雾霾程度加重时校园室外空气中细菌、霉菌菌落总数均随之升高,而室内空气微生物浓度与雾霾程度关联较小.     

妊娠期压力测量方法研究进展

随着对妊娠期压力认识的深化,妊娠期压力的测量方法 也在不断改进.该文将从不同妊娠周期压力测量工具的选择、主观和客观两种压力测量方式、正性和负性两类压力测量维度以及妊娠期压力测量方法 在研究中的应用几方面对妊娠期压力测量方法 的研究进展作一综述.     

Factors affecting the precision of bone mineral measurements. Part 1: Review of experimentally derived results obtained from single photon absorptiometry

An evaluation of the factors which influence the precision of bone mineral measurements using single photon absorptiometry (SPA) is presented. This incorporates several techniques which have been developed over the past few years to improve the reliability of such measurements. As such, the figures obtained should provide an objective and up-to-date basis for critical comparison with other modalities such as quantitative computerized tomography (QCT), dual photon absorptiometry (DPA) using Gd-153, and quantitative digital radiography (QDR). Under optimum conditions, a precision of 0.3% was achievable for in vitro phantom measurements. Under realistic working conditions, however, a precision of 1.0% for phantoms and 1.4% for clinical studies was found to be more typical for bone mineral content (BMC) measurements. Derived parameters such as bone mineral density (BMD) were generally less reliable, with a precision of 4.7%. It is unlikely that these values can be improved upon substantially with current SPA technology.     

基于ARIMA和LSTM神经网络的乌鲁木齐市乙型肝炎发病预测研究

目的 了解乌鲁木齐市2012—2021年乙肝发病趋势,建立合适的发病预测模型,探讨ARIMA模型和LSTM神经网络在乙肝发病预测中的应用。方法 根据2012—2021年乙肝月报告病例数据,建立ARIMA模型和LSTM神经网络模型,对乌鲁木齐市乙肝发病数进行拟合及预测,通过比较RMSE的大小评价模型效果。结果 LSTM神经网络模型拟合和预测的RMSE分别为50.13、42.70,ARIMA(0,1,1)(0,0,2)12模型拟合和预测的RMSE分别为67.62、66.85。前者的拟合及预测效果显著优于后者。结论 乌鲁木齐市10年来乙肝发病呈逐年下降趋势,且存在一定季节性变化。LSTM神经网络模型可较好地拟合和预测乌鲁木齐市乙肝的发病数及趋势,且模型效果优于ARIMA(0,1,1)(0,0,2)12,能在一定程度上提高预测精确度。