重金属单一污染对龙须草叶绿素含量和抗氧化酶系统的影响

盆栽试验的结果表明:Cd、Pb、Cu、Zn和As单一污染处理时龙须草叶绿素含量随着重金属处理浓度的增加呈现先升后降的趋势,但其总叶绿素含量和叶绿素a/b比值均低于对照;龙须草SOD的活性随着Zn、As单一污染处理浓度增加呈现先升后降的趋势,而随着其它三种重金属处理浓度的增加呈现下降趋势;龙须草CAT和POD的活性随着As处理浓度的增加呈现出上升趋势,而随着其它四种重金属处理浓度的增加呈现先升后降趋势。     

单一重金属胁迫对灯心草生长及生理生化指标的影响

通过盆栽试验研究了不同浓度处理水平的Cu、Cd、Pb、Zn、As五种重金属单一胁迫对灯心草生长及其生理生化特性的的影响。结果表明:种植灯心草土壤中的Cd、Pb、Cu三种重金属临界值可分别设定为10mg kg-1、100 mg kg-1、100mg kg-1。灯心草不适合在Zn污染的土壤中种植,土壤中As临界值尚需作进一步的研究来确定。各单一重金属胁迫对灯心草叶绿素的合成均有很大程度的抑制作用,剂量-效应关系明显。灯心草三种保护酶对于不同浓度处理水平重金属胁迫的响应不同:在土壤环境质量低浓度设置范围内三种酶有较好的协同效应能共同抵御重金属胁迫造成的膜伤害,表现出较强的自我调节能力。而在高浓度处理水平时,三种酶活性呈现不同的变化趋势。灯心草生理生化指标对重金属胁迫的响应存在元素种类之间的差异。各单一重金属对灯心草生长抑制及生理毒害效应大小排序为:Zn>As>Cu>Pb>Cd。     

Cd、Pb、Cu、Zn、As复合污染对龙须草生长的影响

本文研究了不同处理水平下Cd、Pb、Cu、Zn、As复合污染对龙须草生长的影响。结果表明,龙须草地下部对重金属的抗性大于地上部。在接近土壤环境质量二级标准上限值时,龙须草生长正常,减产幅度<10%;在含Cd5mgkg-1、Pb600mgkg-1、Cu125mgkg-1、Zn300mgkg-1、As50mgkg-1的复合污染土壤上,龙须草地下部干重与对照相比较差异性不显著(α=0.01);在含矿毒水河水污染土壤和尾矿砂污染水稻土壤上,龙须草地下部干重与对照相当,且地上部干重分别为对照的61.58%和40.64%。这些说明龙须草在土壤重金属复合污染修复中具有良好的应用前景。     

红透山铜尾矿重金属分布及其对土壤重金属污染的影响

通过对红透山铜尾矿重金属分布及尾矿区和农田区土壤重金属污染状况进行研究,结果显示:尾矿中四种重金属Cu、Zn、Ph、Cd均出现不同程度的淋滤-富集现象,对周围土壤存在较大的环境威胁.尾矿区土壤综合污染指数16.27,达重污染程度;周围农田土壤为轻度污染,综合污染指数1.29.四种重金属的污染状况分别为:Cd、Cu为重度污染,Zn为轻度污染,Pb为安全级别.     

不同利用年限的红壤水稻土中重金属元素含量研究

本文介绍了不同利用年限的红壤水稻土中重金属元素As、Cd、Cr、Cu、Ni、Pb和Zn的含量变化,利用年限分别为3、10、15、30和80年。研究结果表明,虽然红壤水稻土中不同的重金属元素含量的变化趋势有所差异,但总体上重金属元素含量随利用年限的延长而降低,并可能达到一个相对稳定的水平;施用未经处理的城市垃圾会导致水稻土中某些重金属元素含量明显升高;研究区的水稻土已发生Cd和Cu污染。     

用计算机数学系统Matlab解决环境污染寻源问题*

为了评价城市土壤中重金属和类金属污染。通过选择319个土壤样品的数据,用计算机数学系统Matlab分析该城市土壤中重金属和类金属(Cd、Cr、Cu、Hg、Ni、Pb、Zn和As)的污染程度。测出土壤综合污染指数为4.34,说明城市属重度污染,该城市已形成偏重度污染的元素为Hg,偏中度污染的元素为Cd和Zn,中度污染的元素为Cu,轻度污染的元素为Pb、Cr、As、Ni,8种重金属和类金属元素对城市的污染严重程度依次为Hg>Cu>Zn>Cd>Pb>Cr>As>Ni。计算机数学系统在环境科学中大有作为,必将成为环境污染监测和预报建模中不可或缺的得力助手。     

水稻冠层与土壤高光谱反演土壤重金属对比研究

针对土壤高光谱与水稻冠层高光谱反演多种土壤重金属含量精度差异较大的问题,探讨2种光谱反演土壤重金属适应性。通过对水稻冠层光谱与其土壤光谱的光谱指标变换,进行对比分析,在此基础上研究多元逐步回归、偏最小二乘回归在不同光谱指标下反演土壤重金属(Fe、Zn、Cu、Pb、Cd)的含量。结果表明,红光、近红外波段为土壤重金属含量敏感波段;水稻冠层波谱反演Fe、Zn、Pb、Cd含量的精度高于土壤波谱的反演精度;土壤波谱反演Cu含量的精度高于水稻冠层波谱反演精度。     

深圳市主要公园及道路绿地土壤重金属含量状况比较研究

对深圳城市主要公园和道路绿地土壤Cu、Zn、Pb、Cd含量状况进行取样调查分析。研究结果表明,绿地土壤重金属含量与土地利用类型有关,表现为道路绿地土壤Cu、Zn、Pb平均含量高于公园绿地土壤,而Cd平均含量则相反。采用不同土壤重金属污染评价方法对深圳城市绿地土壤进行的环境质量评价均表明深圳城市绿地土壤Cd污染现象显著。在考察的四种重金属元素中,Zn含量与土壤有机质、pH有关,其中pH对Zn含量的影响相对较大;土壤Cu与Pb、Zn呈直线相关,表现出相互依存的关系。     

贵溪冶炼厂周边农田土壤重金属污染特性及评价

在对贵溪冶炼厂周边区域的农田土壤及生产的稻谷进行采样调查和数据处理分析的基础上,对农田土壤重金属污染特性和现状进行了监测和初步评价,结果表明:农田土壤重金属污染可能来源于贵溪冶炼厂废水的排放及尾矿渣的堆放,与灌溉水源无关;用国家土壤环境质量二级标准进行评价可知,农田土壤重金属的综合污染指数较高,土壤污染已处于重度污染等级,单项重金属污染指数表明Cu、Cd的含量已严重超标,并处于重度污染等级,Zn、Pb和As的含量未构成污染;水泉村、竹山村与所生产的稻谷三者之间呈显著或极显著正相关,即农田生态系统呈复合污染的趋势。     

低分子有机酸对土壤中重金属的解吸及影响因素

研究了柠檬酸、草酸、酒石酸和苹果酸对矿区土壤中重金属Pb、Cd、Cu和Zn的解吸行为,并探讨了介质pH值对其解吸土中重金属的影响。振荡解吸试验结果表明四种低分子有机酸对供试污染土壤中Pb、Cd、Cu和Zn都具有一定的解吸能力。由于土壤中重金属有效态含量较低,各重金属的解吸率都不高。在对Pb和Cd的解吸中,各低分子有机酸能力大小顺序为柠檬酸>酒石酸≈苹果酸>草酸;Cu的解吸顺序为柠檬酸>草酸>酒石酸≈苹果酸;Zn的解吸顺序为酒石酸>柠檬酸≈苹果酸>草酸。低分子有机酸随浓度的增加,其解吸能力提高。低分子有机酸对重金属的解吸量随pH值的降低而增加。     

抑制剂在长效专用肥生产中的应用

高浓度、复合、专用、长效是肥料发展的必然趋势。长效专用复混肥是在普通专用复混肥基础上,适当调整其氮、磷、钾的配比,并加入抑制剂而制成。该产品已多家肥厂生产,成本比普通专用肥增加35元/t,己在辽宁、山东、新疆等地推广应用,供试作物有玉米、小麦、水稻、棉花等,与同等养分或同等价格的普通专用肥相比,可增产10-15%,肥料利用率提高20%以上,并可达到基肥一次施入,免除追肥,较好地解决了农业高新技术不便追肥的难题。     

Phase equilibria calculations of Al---Sb, Al---Ga and Al---Ga---Sb systems

A quasi sub-subregular solution model is used to describe thermodynamic properties of the liquid phases in Al-Sb, Al-Ga and Al-Ga-Sb systems. An essentially stoichiometeric compound, AlSb, in the Al-Sb binary system is considered as a line compound and the ternary compound, (Al_yGa_1−y)Sb, in Al-Ga-Sb system is described as a regular solution of stoichiometeric compounds, AlSb and GaSb. The model parameters for different phases are obtained by simultaneous optimization with respect to the available thermodynarnic and phase equilibria data of these systems. Phase diagrams and thermodynamic data are, then, calculated by using the optimised model parameters and compared with the experimental data.     

Implementation and development of an automated, ultra-high-capacity, acoustic, flexible dispensing platform for assay-ready plate delivery

Compound management faces the daily challenge of providing high-quality samples to drug discovery. The advent of new screening technologies has seen demand for liquid samples move toward nanoliter ranges, dispensed by contactless acoustic droplet ejection. Within AstraZeneca, a totally integrated assay-ready plate production platform has been created to fully exploit the advantages of this technology. This enables compound management to efficiently deliver large throughputs demanded by high-throughput screening while maintaining regular delivery of smaller numbers of compounds in varying plate formats for cellular or biochemical concentration-response curves in support of hit and lead optimization (structure-activity relationship screening). The automation solution, CODA, has the capability to deliver compounds on demand for single- and multiple-concentration ranges, in batch sizes ranging from 1 sample to 2 million samples, integrating seamlessly into local compound and test management systems. The software handles compound orders intelligently, grouping test requests together dependent on output plate type and serial dilution ranges so that source compound vessels are shared among numerous tests, ensuring conservation of sample, reduced labware and costs, and efficiency of work cell logistics. We describe the development of CODA to address the customer demand, challenges experienced, learning made, and subsequent enhancements.     

Determining Feasibility and Parameter Values for Compound Orders Based on Transfer Amounts, Liquid Handler Capabilities, and Container Volume Capacities

An algorithm is described for determining feasibility and calculating parameter values for one or more compound processing orders. Feasibility is determined primarily by applying a series of inequality constraints that result in a valid target concentration range within which orders can be processed. These inequality constraints are obtained from initial compound amounts, source and destination container volume capacities, the liquid handler transfer volume range, and the amount of compound to be processed. If feasible, calculated parameter values include the dilution, transfer and top-off volumes necessary to fulfill the order. Sample code implementing the algorithm is given in Microsoft Visual Basic®.     

Computational study of structural,optoelectronic and nonlinear optical properties of dynamic solid-state chalcone derivatives

In the present study, we use the state of art density functional theory (DFT) techniques to calculate the structural, optoelectronic and nonlinear optical (NLO) properties for two novel chalcone derivatives. The geometrical structures of chalcone derivatives compound 1 and 2 are optimized using periodic boundary conditions (PBC) in solid-state phase as well as isolated single molecular geometry in the gas phase. The reasonable agreement is found among experimental, solid-state and gas phase single molecular geometries, which provide us, further confidence to explore the potential of above-entitled derivatives as good functional materials for electro-optical applications. For instance, the frequency dependent real parts of dielectric functions are calculated for compound 1 and 2. The maximum value of real part of the dielectric function for compound 1 and 2 at 0 eV are computed as 4.35 and 6.68 for the polarization vectors of (001) directions, respectively, which reveals the fact that the compound 1 and 2 might be good charge transport materials. The reflectivities of the compound 1 and 2 are 0.64 and 0.45 revealing that the compound 2 might be more efficient material for organic photovoltaic (OPV) applications. The results of the refractive index improved by doping the strong electron withdrawing groups (EWGs) shows that the compound 2 might be good refractor of the photon as compared to compound 1. The calculated values for static second-order polarizability are 3498 and 10464 a. u. and for frequency dependent second harmonic generations are 2557 and 6429 a. u. for compound 1 and 2, respectively, which indicates their significant potential for possible nonlinear optical applications.     

复方降脂中药的性味归经与药效的BPNN研究

针对复方中药药效与其性味归经之间复杂的、不确定的关系,建立适于复方降脂中药的BP神经网络模型,运用Matlab快速预测复方降脂中药的药效指标。经验证,该方法为一种快速、可靠的方法。     

复合微生物制剂对重茬草莓生长及产量品质的影响研究

试验研究了复合微生物制剂对重茬草莓植株生长及产量品质的影响。结果表明,复合微生物制剂对重茬未消毒土壤的草莓黄萎病防效达76.9%~84.6%。无论土壤是否消毒,复合微生物制剂均可提高草莓叶片的光合速率和叶绿素含量,促进草莓植株的生长,使物候期提前;显著提高草莓果实维生素C和可溶性糖的含量,改善果实品质和风味;草莓增产14.21%~16.20%。同时复合微生物制剂还可以改善土壤的理化性状,提高土壤肥力。     

Surface treatment,reflectance, and age effects on electronic‐paper reading performance

Abstract— This study is intended to explore the legibility and visual fatigue of different age users under various surface treatments and reflectance of electronic paper. Through the method of character‐search task, the results indicated that compared with single types of treatment [anti‐reflection (AR) 0.8%, anti‐glare, 43% haze), the compound treatment of anti‐reflection and anti‐glare (ARC) exhibited the same legibility, and it showed superior properties to effectively reduce visual fatigue. Hence, it is suggested that electronic‐paper manufacturers should choose the compound surface treatment for better visual performance. On the other hand, the findings also validated that enhancing the reflectance of electronic paper to the same level as regular paper (about 80%) is worthy to be practically implemented. Based on the results of this study, electronic‐paper manufacturers can take useful information to fulfill ergonomic requirements on product design.     

Thermodynamic analysis of the In-P, Ga-As, In-As And Al-Sb Systems

Thermodynamic and phase diagram data are used to optimize the thermodynamic model parameter values of the liquid phases in four III-V binary systems: In-P, Ga-As, In-As and Al-Sb. An associated solution model is used to describe the thermodynamic properties of the liquid phases and the III-V compound semiconductors are taken to be stoichiometric (or line) compounds. For each of the binary systems, a set of thermodynamic parameters for the liquid and compound semiconductors are obtained. Using these values, the calculated phase diagrams are in agreement with the experimentally determined ones. Moreover, the model-calculated thermodynamic values also in agreement with the experimentally determined values.     

IQ technology: an automated, high-throughput screening assay for kinase, phosphatase, and protease targets

IQ^® Technology, a homogeneous, universal-detection platform, originally designed for high-throughput screening (HTS) of kinases and phosphatases, has now been applied to protease screening. Representative enzymes from the major classes of proteases have been assayed in the IQ^® format. Enzyme activity and compound inhibition data are presented for such enzymes as Trypsin, Matrix Metalloproteinase 3 (MMP-3) and Calpain 1. The technology has been tested in 96- to 384- to 1536-well microplate formats and is universally suited for automated screening. IQ^® Technology is a direct, noncompetitive assay that does not require antibodies or radioisotopes. Fluorophore-labeled peptides are used as enzyme substrates. Kinase or phosphatase activity is quantified by direct measurement of the phosphorylation state of the substrate. For protease activity, cleavage is quantified with a peptide substrate containing a phospho-residue distal to the fluorphore. Cleavage of the substrate liberates the fluorphore-labeled terminus from the terminus containing the phospho-residue. Protease activity is measured by the change in fluorescence intensity that occurs when a proprietary compound binds specifically to phosphoryl groups on peptides and quenches the fluorescence. IQ^® Technology can be used with any peptide sequence and is insensitive to high concentrations of ATP and substrate. The IQ^® Technology has been validated against a large number of detergents, organics, and other reagents found in reaction mixtures and has been optimized for HTS applications exhibiting representative Z' values of 0.7.