A pharmacokinetic modeling of inorganic arsenic: a short-term oral exposure model for humans

This study presents a pharmacokinetic modeling of inorganic arsenic disposition in human body for short-term oral exposures. Effort on the development of the model is directed toward the prediction of the kinetic behavior of inorganic arsenic and its metabolites in the body. The current model considers the 4 circulating species; As^III, As^v, and two metabolites such as monomethylarsenic (MMA) and dimethylarsenic (DMA) in the blood and tissue groups. While it is difficult to estimate some parameters used in the models at this time, the current model assumptions and predictions seem to be consistent with the experimental observations found in the literature. Hence, the current model, when more fully developed, is expected to provide insight into the behavior of inorganic arsenic and its methylated metabolites within the body, and may help increase the understanding of risk assessment issues associated with inorganic arsenic in drinking water.     

杭州市空气细颗粒物浓度与哮喘就诊人次的关系

为研究大气细颗粒物污染对哮喘门诊就诊的短期影响及各人群的易感性差异,收集杭州市某医院2013年1月1日至2015年12月31日哮喘门诊(含急诊)资料,以及同期空气污染数据和气象数据,考虑到污染物浓度与呼吸系统疾病就诊人次及气象因素之间的非线性关系,采用时间序列广义相加模型及分层分析的方法研究空气污染对哮喘影响的滞后效应及人群按性别、年龄分层的易感性差异,对平均温度、平均相对湿度及长期趋势等采用自然立方样条函数进行平滑拟合,同时用哑元变量控制星期几效应和节假日效应的影响.在P=0.01水平下PM_(2.5)、NO_2、SO_2之间均呈显著的正相关性,而气温与3种污染物之间呈显著的负相关性.PM_(2.5)日均浓度每升高10μg·m~(-3),对哮喘就诊人次影响的相对危险度(relative risk,RR)在滞后5d达到最大值,为1.005 6(95%CI:1.002 1~1.009 1),且具有统计学意义(P0.05).在男性人群和18~64岁人群中,细颗粒物浓度对于哮喘就诊人次的影响在滞后3~5 d的RR值均具有统计学意义,在女性人群和≥65岁人群中,在滞后5 d时RR值均具有统计学意义.在多污染物模型中,引入NO_2的影响后PM_(2.5)对哮喘就诊人次的影响在滞后5 d时的RR有所提升.杭州市PM_(2.5)浓度的升高可能会造成3~5 d内哮喘门诊就诊人次的增加,且对男性人群和老年人群影响更为明显.     

Financial inadequacy and the disadvantageous changes in time perspective and goal-striving strategies throughout life

As inequality in wealth and income continues to grow, it is important to consider the implications of financial disparities for worker motivation and behavior. While workers with socioeconomic disadvantages have a decreased chance of career success and upward social mobility, the potential mechanisms linking financial status to work motivation outcomes are not fully known. Drawing on theory on resource scarcity, we address this issue and propose that financial inadequacy shapes the extent to which workers consider and plan for the future, with consequences for goal-striving strategies throughout adulthood. Latent change analyses of data from a heterogeneous sample of 4,446 working adults largely supported the hypotheses. Results showed that a high level of financial inadequacy predicted increases in short-term time horizon and decreases in future-oriented planning, which then predicted disadvantageous changes in goal-striving strategies over an 18-year period. Short-term time horizon also predicted subsequent increases in financial inadequacy. By highlighting the motivational challenges associated with inadequate finances that accompany low-wage employment, our study offers evidence for the motivational mechanisms that may reinforce economic inequality and social mobility in the workforce.     

Pollution characteristics of lead,zinc, arsenic,and cadmium in short-term storm water roof runoff in a suburban area

Pollution of hazardous elements in roof runoff has been a potential danger to aquatic ecosystem as documented in previous studies. In this study, concentrations of lead (Pb), zinc (Zn), arsenic (As), and cadmium (Cd) in roof runoff were measured for short-term rainfall events. The concentrations of the selected elements varied to a high degree during the rainfall period, and the well-known first-flush phenomenon was not observed due to the short-term rainfall patterns. Based on event mean concentrations (EMCs) and fluxes, the elemental pollution may be ranked as Zn >> Pb > As > Cd. The average levels of Pb and Zn exceeded the fourth class value and fifth class value of the environmental quality standards for surface water in China. The relative high pollution could be caused by atmospheric deposition and the erosion of crust steel appurtenance installed above the rooftop. Furthermore, elements in particulate form dominated the roof runoff pollution, and the ratios of elements in particulate form to total amounts were 0.6 (As), 0.9 (Pb), 0.7 (Cd), and 0.5 (Zn). This study cleared the pollution characteristics of hazardous elements in short-term storm water roof runoff; it was useful for the selection of best management practices.     

Response of bacterial communities to short-term pyrene exposure in red soil

Pyrene, a representative polycyclic aromatic hydrocarbon (PAH) compound produced mainly from incomplete combustion of fossil fuels, is hazardous to ecosystem health. However, long-term exposure studies did not detect any significant effects of pyrene on soil microorganism. In this study, short-term microcosm experiments were conducted to identify the immediate effect of pyrene on soil bacterial communities. A freshly-collected pristine red soil was spiked with pyrene at 0, 10, 100, 200, and 500 mg·kg^-1 and incubated for one day and seven days. The bacterial communities in the incubated soils were analyzed using 16S rRNA sequencing and terminal restriction fragment length polymorphism (T-RFLP) methods. The results revealed high bacterial diversity in both unspiked and pyrene-spiked soils. Only at the highest pyrene-spiking rate of 500 mg·kg^-1, two minor bacteria groups of the identified 14 most abundant bacteria groups were completely suppressed. Short-term exposure to pyrene resulted in dominance of Proteobacteria in soil, followed by Acidobacteria, Firmutes, and Bacteroidetes. Our findings showed that bacterial community structure did respond to the presence of pyrene but recovered rapidly from the perturbation. The intensity of impact and the rate of recovery showed some pyrene dosage-dependent trends. Our results revealed that different levels of pyrene may affect the bacterial community structure by suppressing or selecting certain groups of bacteria. It was also found that the bacterial community was most susceptible to pyrene within one day of the chemical addition.     

基于机器学习的短临预报方法及其在空气质量保障中的应用

基于多个数值模式(NAQPMS、CMAQ)预报结果和站点观测资料,采用岭回归机器学习方法构建了一种多污染物短临预报方法,并应用于2017年厦门金砖国家峰会和2019年武汉军运会空气质量保障工作,评估总结了短临预报方法的可行性和预报效果.结果表明:短临预报表现出很好的预报能力,可以有效改进数值模式的预报趋势和量值.从日均...     

基于长短时记忆网络的水质预测模型研究

在当前水质数据急剧增加的背景下,为了挖掘水质时间序列中的更多信息,提升水质预测的精度,构建了基于缺失值填补算法和长短时记忆网络(LSTM)相结合的水质预测模型。通过缺失值填补算法进行水质数据的缺失值处理,利用LSTM网络分别构建不同水质参数的预测模型,以太湖水质监测数据为样本,对模型进行检验。结果表明,基于缺失值填补算法-LSTM的水质预测模型适应性强,相较传统SVM、BP神经网络、RNN、LSTM模型预测精度更高,对水环境保护具有重要意义。     

鱼类和两栖类胚胎幼体慢性毒性短期试验

采用鲤鱼和黑斑蛙进行了丙烯腈、乙腈、硫氰酸钠和二甲基甲酰胺等４种污染物的鱼类和两栖类胚胎幼体毒性试验．结果表明，４种污染物对鲤鱼的慢性毒性值分别为２．２６、５５６、２８．３和１１３１ｍｇ／Ｌ，已腈、硫氰酸钠和二甲基甲酰胺对黑斑蛙的慢性毒性值分别为２８２８、５６．５和４５２５ｍｇ／Ｌ，说明采用胚胎幼体试验能够有效地预测污染物的慢性毒性效应．