荧光免疫层析法结合免疫磁珠分离技术快速检测单增李斯特菌

为建立单增李斯特菌简单快速、灵敏度高和特异性强的检测方法,本研究以抗单增李斯特菌单克隆抗体偶联磁珠制备免疫磁珠;以羧基荧光微球标记的抗单增李斯特菌多克隆抗体及鼠IgG为标记抗体,抗单增李斯特菌多克隆抗体和羊抗鼠二抗分别作为检测线和质控线制备荧光免疫层析试纸条。将免疫磁珠分离与荧光免疫层析法相结合应用于单增李斯特菌的现场快速检测中。结果表明:荧光免疫层析试纸条对纯培养单增李斯特菌的检测限为4×105CFU/mL,联合检测方法10倍、100倍浓缩时,检测限分别为4×104CFU/mL和1×104CFU/mL。联合检测体系特异性较好,与实验室保存的10株细菌无交叉反应。人工污染样本检测限为1×104CFU/mL,同纯培养物相比检测灵敏度并没有降低。本方法的建立对于食品中单增李斯特菌的现场快速检测具有重要意义。     

湿法消解-电感耦合等离子体发射光谱法测定保健食品中7种常见矿物质元素

目的建立湿法消解-电感耦合等离子体发射光谱法测定保健食品中铜、锰、铁、锌、钙、镁、钾7种常见矿物质元素的含量。方法使用高氯酸含量较高的硝酸-高氯酸体系湿法消解样品,彻底消解保健食品中难以消解的植物油、甘油、乙二醇、二氧化钛等化合物,使用电感耦合等离子体发射光谱法配备更节省氩气的微型炬管上机测定样品。结果在一定质量浓度范围内, 7种元素线性关系良好,相关系数大于0.999,检出限为0.2~10mg/kg,定量限为0.6~30mg/kg,加标回收率在92.1%~104.7%,相对标准偏差小于3.89%。结论本方法前处理消解样品完全、物理化学干扰少、结果准确可靠,具有良好的精密度和回收率,适用于保健食品中7种常见矿物质元素的准确检测。     

QuEChERS-超高效液相色谱-串联质谱法测定红酒中4种生物胺含量

摘 要: 目的 建立QuEChERS-超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)同时检测红酒中组胺、酪胺、色胺和苯乙胺4种生物胺的分析方法。方法 红酒样品经改进的 QuEChERS混合填料净化后, 经ACQUITY UPLC? BEH Amide色谱柱（2.1mm×100mm,1.7μm）和0.1%(V/V)甲酸-15mmol/L乙酸铵水溶液和乙腈梯度洗脱分离,质谱(ESI+)采用多反应监测模式(multiple response monitoring, MRM), 外标法定量。结果 组胺、酪胺、色胺和苯乙胺4种目标化合物在色谱柱上有很好的保留,在1.00～800 μg/L范围内具有良好线性（R2>0.9995）,4种目标化合物的检出限为1.0μg/L,4种化合物的回收率范围为94.7%～106.7%,相对标准偏差（RSD, n=6）为3.7%～8.1% 结论 该方法简单快、快速、结果准确、灵敏度高, 适合测定红酒中组胺、酪胺、色胺和苯乙胺4种生物胺。     

某铀矿上下分区间保安矿柱破坏规律研究

对某铀矿上下分区间保安矿柱破坏规律进行了研究,采用FLAC3D进行数值模拟,确定12m为水平保安矿柱的安全厚度。同时对矿柱破坏引发的上盘岩体失稳演化过程进行了分析,由于矿体的开采,造成地应力二次分布,在开采区上盘形成卸压区和承压区,矿柱也发生从稳定阶段到变形阶段、破坏阶段的演化,与岩石的压破坏类似,水平保安矿柱的破坏机制符合岩石的破坏规律。     

Quantifying the trustworthiness of social media content

The growing popularity of social media in recent years has resulted in the creation of an enormous amount of user-generated content. A significant portion of this information is useful and has proven to be a great source of knowledge. However, since much of this information has been contributed by strangers with little or no apparent reputation to speak of, there is no easy way to detect whether the content is trustworthy. Search engines are the gateways to knowledge but search relevance cannot guarantee that the content in the search results is trustworthy. A casual observer might not be able to differentiate between trustworthy and untrustworthy content. This work is focused on the problem of quantifying the value of such shared content with respect to its trustworthiness. In particular, the focus is on shared health content as the negative impact of acting on untrustworthy content is high in this domain. Health content from two social media applications, Wikipedia and Daily Strength, is used for this study. Sociological notions of trust are used to motivate the search for a solution. A two-step unsupervised, feature-driven approach is proposed for this purpose: a feature identification step in which relevant information categories are specified and suitable features are identified, and a quantification step for which various unsupervised scoring models are proposed. Results indicate that this approach is effective and can be adapted to disparate social media applications with ease.     

Porous Surfaces Via Impinging and Solidifying Molten Hollow Melt Droplets on Substrates

We numerically study impingement and solidification of a molten hollow droplet onto a surface during thermal spray coating process. In the impingement model transient flow during the hollow droplet impact, subsequent spreading and solidification, and air entrapment are considered using the volume of fluid surface tracking method coupled with the solidification model within a one-domain continuum formulation. A phenomenon of counter liquid jetting is observed which causes large air entrapment and porous deposited layer. This will have potential prospects in improving the thermal insulation properties of surfaces in turbine blades, engine components applications.     

Silver nanowire/polymer composite soft conductive film fabricated by large-area compatible coating for flexible pressure sensor array

Soft conductive films composed of a silver nanowire (AgNW) network,a neutral-pH PEDOT:PSS overcoating layer and a polydimethylsiloxane (PDMS) elastomer substrate are fabricated by large area compatible coating processes.The neutral-pH PEDOT:PSS layer is shown to be able to significantly improve the conductivity,stretchability and air stability of the conductive films.The soft conductive films are patterned using a simple maskless patterning approach to fabricate an 8 × 8 flexible pressure sensor array.It is shown that such soft conductive films can help to improve the sensitivity and reduce the signal crosstalk over the pressure sensor array.     

Performance of polypropylene textile encased stone columns

This paper explores the potential use of a woven polypropylene textile for encapsulating stone columns and improving performance of a local soft soil in Warangal city of India. A series of axial load tests were performed on stone columns of various diameters and under various encapsulation conditions that include single and double layers and other combinations. Load carrying capacity of stone column increased twice its original capacity when encapsulated with different geofabric materials. Performance enhancement strongly correlated to the tensile strength of encasement material and encapsulation condition. In addition, the influence of lateral thrust on group of stone columns arranged in square and triangular patterns were investigated. Irrespective of the material used, lateral displacement reduced by half for encased stone columns. Apart from tensile strength of encasing material, the amount of material used for encasement in the form of additional encasement layer was found to be crucial. The cost of using the polypropylene encasing material is only a third of the commercial geotextiles; however, the performance is inferior to woven geotextiles but far superior to non-woven geotextiles.     

Interactions of energy technology development and new energy exploitation with water technology development in China

Interactions of energy policies with water technology development in China are investigated using a hybrid input-output model and scenario analysis. The implementation of energy policies and water technology development can produce co-benefits for each other. Water saving potential of energy technology development is much larger than that of new energy exploitation. From the viewpoint of proportions of water saving co-benefits of energy policies, energy sectors benefit the most. From the viewpoint of proportions of energy saving and CO₂ mitigation co-benefits of water technology development, water sector benefits the most. Moreover, economic sectors are classified into four categories concerning co-benefits on water saving, energy saving and CO₂ mitigation. Sectors in categories 1 and 2 have big direct co-benefits. Thus, they can take additional responsibility for water and energy saving and CO₂ mitigation. If China implements life cycle materials management, sectors in category 3 can also take additional responsibility for water and energy saving and CO₂ mitigation. Sectors in category 4 have few co-benefits from both direct and accumulative perspectives. Thus, putting additional responsibility on sectors in category 4 might produce pressure for their economic development.     

On the Decarburization of Surface Pearlite

Metallurgical and Materials Transactions A - Under appropriate conditions, surface pearlite can form on the outer surfaces of specimen. The microstructure evolution during the decarburization of...