浮游动物DNA宏条形码标志基因比较研究

DNA宏条形码技术作为一种新型生物监测方法,在未来生态环境监测中有巨大的应用潜力。目前,浮游动物DNA宏条形码监测仍在发展阶段,需要首先对其(采样方法、引物选择和数据分析等)进行标准化和调整,然后才能用于常规流域生态监测。其中,如何选择合适的PCR扩增引物是DNA宏条形码生物监测标准化的关键问题之一。本研究比较了COI、18SV9和16S通用引物在浮游动物DNA宏条形码监测中的差异,为初步建立规范化的浮游动物DNA宏条形码监测方法提供技术支撑。结果表明,16S引物对浮游动物具有更好的特异性,其产生的操作分类单元(operational taxonomic unit, OTU)有88.1%属于浮游动物。虽然18SV9引物具有更高的物种覆盖度,不仅能扩增出浮游动物,还能扩增出大量藻类和真菌,但其物种识别敏感性较差,不适合浮游动物物种水平多样性监测。COI引物的浮游动物物种特异性、物种覆盖度和物种识别敏感性都适中,检出的浮游动物物种数量高于18SV9引物和16S引物,更加适合浮游动物DNA宏条形码监测。     

空气污染天气过程与气象要素之间的关联性分析

随着经济和社会的不断发展,地球的环境正在遭受着严重的侵害,关于环境的问题也日益显现出来,比如全球变暖、雾霾等现象。本文分析了空气污染的因素、气象要素对空气质量的影响,并提出了防治空气污染的对策。     

伊犁盆地昭苏黄土不同粒径和相态稀土元素特征及其物源指示意义

为了探讨伊犁盆地风成沉积物质来源特征,对伊犁地区昭苏黄土剖面代表性样品各个 粒级全岩、酸溶组分和残渣组分中的稀土元素进行了分析。结果表明,各个粒级组分全岩样品 的稀土总量（ΣREE）的变化范围为114.61~178.37 μg·g?1,剖面中各个粒级组分稀土球粒陨石标 准化配分模式呈轻稀土富集,存在明显的Eu 负异常,Ce 无明显异常。各个粒级组分酸溶残渣 稀土特征与上述全岩特征类似。酸溶组分稀土的上部大陆地壳标准化呈现稳定的中稀土富集。 随着各组分粒级变粗,酸溶组分稀土占全岩比例呈现先降低后升高的趋势,即从<2 μm 组分到 16 ~32 μm 组分比例渐次降低,而后从16 ~32 μm 组分到>63 μm 渐次升高,这主要反映了以西风 为代表的远源输送体系和以近地面风为代表的近源输送体系下两种来源的碎屑碳酸盐稀土的混 合。本文不同粒径和赋存形态下稀土元素的特征表明了利用风成沉积物稀土元素反映源区物质 特征存在一定复杂性。     

流化床O2/CO2气氛燃煤痕量元素的排放特性及控制

通过平顶山烟煤在小型流化床中的燃烧实验,采用X-射线荧光光谱仪(XRF)对低压撞击器(LPI)收集到的细颗粒物元素组成进行定量测定,研究了O2/CO2气氛下硅藻土对煤粉燃烧痕量元素的排放控制.结果表明,Zn、Mn和Ni的含量随粒径呈双峰分布,峰值分别在0.1μm和2μm附近,Hg和Co的含量在0.1μm附近有一峰值;Hg和Zn在亚微米颗粒上有一定程度的富集,Mn、Ni和Co在亚微米和超微米颗粒上的含量基本相当;当颗粒物粒径一定时,随着硅藻土含量的增加,5种元素的富集因子呈减小的趋势;随着添加剂粒径的减小,颗粒物中Hg、Mn、Zn、Ni和Co的含量呈减少的趋势;当颗粒物粒径一定时,5种元素含量顺序为MnZnNiCoHg.     

北京河流水污染现状分析研究

通过总结近年来北京河流中氮磷、有机质和重金属等方面的研究成果,结果表明北运河水系各河段水质均较差,劣Ⅴ类水质的河流长度超过80％,城市河流污染特征明显,主要污染指标为耗氧型有机污染物和氨氮,重金属污染较轻,悬浮物中的重金属占较大的比重;永定河水系枯水期氮污染较重,主要是硝态氮超标,以颗粒态磷为主要形式的磷污染较轻,重金属含量大都低于地表水Ⅲ类标准;潮白河水系水质较好,各水质指标除个别断面外大都满足中Ⅲ类水标准,重金属含量大都符合Ⅰ～Ⅲ类水标准。     

微波消解－ICP－MS法测定土壤中稀土元素的研究

建立了电感耦合等离子体质谱（ ICP－MS）测定土壤中稀土元素的分析方法。采用HNO3＋HF酸体系用微波消解对土壤样品进行处理,以混合内标（ In、Bi）校正基体干扰和信号漂移,用ICP－MS对其中的16种稀土元素进行了测定。在优化的实验条件下,16种稀土元素标准曲线的相关系数r＞0．9999,检出限为0.012 ng／ml～0.069 ng／ml,加标回收率为84.0％～110％,相对标准偏差（n＝6）RSD均小于3.5％。该方法可用于四种不同类型土壤中稀土元素含量的测定。     

Contamination and vertical distribution of As,Cd, Cr,Cu, Pb,Tl, and Zn in paddy soil irrigated with untreated leachate from tailings retention ponds

The contamination and vertical distribution of As, Cd, Cr, Cu, Pb, Tl, and Zn in paddy soil irrigated with untreated leachate from the tailings retention pond were investigated. As, Cr, Cu, and Zn were slightly contaminated in the surface soil and hence their vertical distribution was not obvious. However, Cd and Pb were highly contaminated in the surface soil, while their concentrations decreased with depth, being negatively correlated with pH and positively with total organic matter. Tl was considerably contaminated in the surface soil and a V-shaped vertical distribution was observed where the concentration increased to a maximum at about 30 cm depth and decreased thereafter. The findings revealed that the regular irrigation with untreated leachate from the tailings retention ponds could cause considerable contamination of Cd, Pb, and Tl, and thus tailings should be stringently treated before disposal to minimize their potential environmental impacts on the surroundings.     

Trace elements in particulate matter of ambient air at petroleum filling stations

Size segregated suspended particulate matter (PM_2.5 and PM_10-2.5) in air at four major petroleum-filling stations in Ile-Ife, Nigeria, were monitored using double staged “Gent” stacked samplers to assess variations in mass loads and elemental concentrations of 25 elements. Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Zr, Cs, Ta, W, and Pb were determined in both fractions by external ion beam proton-induced X-ray emission technique. Enrichment factors and pollution indices were calculated and results revealed that most elements were anthropogenic in both fractions with concentrations exceeding the World Health Organization guideline standards.     

基于两种样品前处理方法对比研究小冬克玛底冰川雪坑中痕量元素

通过对唐古拉山小冬克玛底冰川雪坑中非季风季节沉积的雪样分别进行酸化处理和消解处理后,利用高分辨扇形磁场等离子体质谱仪(ICP-SFMS)测试了样品中19种痕量元素(Ba、U、Sr、Rb、Tl、Mo、Cs、Pb、Sb、V、Cr、Mn、Fe、Co、Al、Cu、Ti、Li、As)的酸化浓度和总浓度.研究结果表明,痕量元素浓度的变化范围较大,元素Al的最大/最小浓度比为326(酸化浓度)和465(总浓度),元素Pb相应比值为27和48.雪冰中痕量元素的总浓度一般大于该元素的酸化浓度,其中,元素Pb、Fe、Sb、Ba、Al、Ti的酸化浓度占总浓度的平均比值分别为91%、76%、60%、52%、33%和21%.一般地,样品中不溶微粒含量越大,酸化浓度占总浓度的比值越小;不溶微粒含量越小,则相反.对痕量元素的富集系数(EF)分析表明,各元素总浓度EF均值小于酸化浓度EF均值,揭示了用酸化浓度计算EF存在对痕量元素人为来源影响的高估.人类排放是小冬克玛底冰川中痕量元素的来源之一,对于元素Mo和Sb,人类排放估计是主要来源.利用后向轨迹模型模拟出小冬克玛底冰川雪冰中痕量元素在非季风季节主要来源于青藏高原西部及中亚中东地区.     

Development and Validation of the Total HUman Model for Safety (THUMS) Toward Further Understanding of Occupant Injury Mechanisms in Precrash and During Crash

Objective: Active safety devices such as automatic emergency brake (AEB) and precrash seat belt have the potential to accomplish further reduction in the number of the fatalities due to automotive accidents. However, their effectiveness should be investigated by more accurate estimations of their interaction with human bodies. Computational human body models are suitable for investigation, especially considering muscular tone effects on occupant motions and injury outcomes. However, the conventional modeling approaches such as multibody models and detailed finite element (FE) models have advantages and disadvantages in computational costs and injury predictions considering muscular tone effects. The objective of this study is to develop and validate a human body FE model with whole body muscles, which can be used for the detailed investigation of interaction between human bodies and vehicular structures including some safety devices precrash and during a crash with relatively low computational costs.

Methods: In this study, we developed a human body FE model called THUMS (Total HUman Model for Safety) with a body size of 50th percentile adult male (AM50) and a sitting posture. The model has anatomical structures of bones, ligaments, muscles, brain, and internal organs. The total number of elements is 281,260, which would realize relatively low computational costs. Deformable material models were assigned to all body parts. The muscle–tendon complexes were modeled by truss elements with Hill-type muscle material and seat belt elements with tension-only material. The THUMS was validated against 35 series of cadaver or volunteer test data on frontal, lateral, and rear impacts. Model validations for 15 series of cadaver test data associated with frontal impacts are presented in this article. The THUMS with a vehicle sled model was applied to investigate effects of muscle activations on occupant kinematics and injury outcomes in specific frontal impact situations with AEB.

Results and Conclusions: In the validations using 5 series of cadaver test data, force–time curves predicted by the THUMS were quantitatively evaluated using correlation and analysis (CORA), which showed good or acceptable agreement with cadaver test data in most cases. The investigation of muscular effects showed that muscle activation levels and timing had significant effects on occupant kinematics and injury outcomes. Although further studies on accident injury reconstruction are needed, the THUMS has the potential for predictions of occupant kinematics and injury outcomes considering muscular tone effects with relatively low computational costs.