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An electrochemiluminescence (ECL) sensor for mercury (II) was developed based on the cation exchange reaction between Hg2þ and CdS due to the large difference in the sedimentation equilibrium constant. To fabricate the sensor, CdS nanowires (CdS NWs) serving as the emitter were introduced upon a glass carbon electrode (GCE). Gold nanoparticles (Au NPs) with excellent electrical conductivity were introduced on the surface of CdS NWs/GCE to enhance the sensor performance. In the presence of Hg2þ, the electrochemiluminescence of the sensor decreased. The electrochemiluminescence intensity was negatively correlated with the concentration of Hg2þ. The excellent performance of Au NPs:CdS NWs/GCE, combined with the difference in the CdS and HgS sedimentation equilibrium constants, endows the sensor with good selectivity and sensitivity for the analyte. A long linear range from 6.7x10-15 M to 1.0x10-8 M was obtained for Hg2þ with a detection limit of 5.0x10-15 M. The applicability of the method was validated by the analysis of water and lake water. [ABSTRACT FROM AUTHOR]

Dopamine has been shown interact strongly with Cu2+ to form a stable complex and inhibit the formation of polythymine-templated copper nanoclusters. Based on these findings, a label-free sensing strategy has been designed for the detection of dopamine using polythymine-templated copper nanoclusters as fluorescence probes. The fluorescent method exhibits sensitive and selective detection of dopamine with a linear range from 1 nM to 50 μM and a detection limit of 0.5 nM. In addition, the method was successfully applied for the determination of dopamine in dopamine hydrochloride injection samples. Thus, this approach holds considerable potential for the construction of a simple, rapid, and sensitive fluorescent assay for the determination of dopamine. [ABSTRACT FROM AUTHOR]

The time-varying plasma sheath surrounding a reentry spacecraft (or object) can influence the radar detection of the spacecraft seriously, causing detection error or even track loss. To study the influence of plasma sheath on radar detection, a time-varying plasma sheath model based on scattering matrix method is constructed. In the model, the surface media of reentry object is considered, together with some algorithm adjustments to avoid computational singularity, and the time-varying characteristics of plasma sheath are taken into account based on available measured data. By the model, the reflection coefficient of plasma sheath and the radar echo reflected by plasma-covered object are both calculated. And then a processing method of time-varying echo signal based on ambiguity function are put forward, by which the time delay and Doppler frequency of echo signal are analyzed. In the simulation, the rules of a series of time-varying parameters of plasma affecting the reflection coefficient are analyzed. Then, by ambiguity function analysis, the influence rules of plasma sheath on radar echo are revealed, accompanied by some qualitative and quantitative results. The proposed model, method, and simulation results are thought to be helpful for the radar detection of plasma-covered reentry objects. [ABSTRACT FROM AUTHOR]

A facile label-free electrochemiluminescence (ECL) aptasensor, based on the ECL of cadmium sulfide- graphene (CdS-GR) nanocomposites with peroxydisulfate as the coreactant, was designed for the detection of carcinoembryonic antigen (CEA). Tripetalous CdS-GR nanocomposites were synthesized through a simple onepot solvothermal method and immobilized on the glassy carbon electrode surface. L-Cystine (L-cys) could largely promote the electron transfer and enhance the ECL intensity. Gold nanoparticles (AuNPs) were assembled onto the L-cys film modified electrode for aptamer immobilization and ECL signal amplification. The aptamer modified with thiol was adsorbed onto the surface of the AuNPs through a Au-S bond. Upon hybridization of the aptamer with the target protein, the sequence could conjugate CEA to form a Y architecture. With CEA as a model analyte, the decreased ECL intensity is proportional to the CEA concentration in the range of 0.01-10.0 ng mL-1 with a detection limit of 3.8 pg mL-1 (S/N = 3). The prepared aptasensor was applied to the determination of CEA in human serum samples. The recoveries of CEA in the human serum samples were between 85.0% and 109.5%, and the RSD values were no more than 3.4%. [ABSTRACT FROM AUTHOR]

The article presents a study on the use of molecularly imprinted polymer in selecting solid-phase extraction for analysis of methamidophos in water and soil samples. The study utilizes several methods including molecularly imprinted polymer (MIP) preparation, binding study and selectivity evaluation of MIP, and soil and water sample preparation and molecularly imprinted polymers (MIPs). It also revealed the binding property of methamidophos-imprinted polymer and its selectivity evaluation.

Lake Donghu is a typical eutrophic freshwater lake in which high abundance of planktonic viruses was recently revealed. In this study, seasonal variation of planktonic viruses were observed at three different trophic sites, hypertrophic, eutrophic, and mesotrophic regions, and the correlation between their abundances and other aquatic environmental components, such as bacterioplankton, chlorophyll a, burst size, pH, dissolved oxygen, and temperature, was analyzed for the period of an year. Virioplankton abundance detected by transmission electron microscope (TEM) ranged from 5.48 × 108 to 2.04 × 109 ml−1 in all the sites throughout the study, and the high abundances and seasonal variations of planktonic viruses were related to the trophic status at the sampled sites in Lake Donghu. Their annual mean abundances were, the highest at the hypertrophic site (1.23×109 ml−1), medium at the eutrophic site (1.19×109 ml−1), and the lowest at the mesotrophic site (1.02×109 ml−1). The VBR (virus-to-bacteria ratio) values were high, ranging from 49 to 56 on average at the three sampled sites. The data suggested that the high viral abundance and high VBR values might be associated with high density of phytoplankton including algae and cyanobacteria in this eutrophic shallow lake, and that planktonic viruses are important members of freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Focuses on the synthesis of a series of chiral phosphite ligands based on chiral binaphthol. Role of rhodium complexes; Catalysts for the asymmetric hydroformylation of styrene and vinyl acetate; Catalytic activities and chemoselectivities; Chiral bidentate phosphite ligands.