高效液相色谱-串联质谱法检测三苯乙烯基苯酚聚氧乙烯醚

建立了高效液相色谱-串联质谱检测三苯乙烯基苯酚聚氧乙烯醚(tristyrylphenol ethoxylates,TSPn EO)的分析方法,并对TSPn EO在反相色谱柱(XBridge C_(18),150 mm×2.1 mm,3.5μm)、亲水相互作用色谱柱(XBridge HILIC,150 m m×2.1 m m,3.5μm)、氨基色谱柱(XBridge Amide,150 m m×2.1 m m,3.5μm)、伪反相色谱柱(C18柱(XBridge C_(18),50 mm×2.1 mm,5μm)与硅胶柱(Nova-Pak Silica,150 mm×2.1 mm,4μm)串联)4种不同液相色谱分离模式下的分离效果进行了研究。实验比较了5 mmol/L乙酸铵水-乙腈、0.1%(v/v)甲酸水-乙腈、水-乙腈和水-甲醇4种流动相组成及3种梯度洗脱条件对分离效果和灵敏度的影响。探讨了TSPnEO在电喷雾离子(ESI)源内的离子化特征,结果表明,在ESI正离子模式下,TSPnEO在离子源内形成[M+NH4]+离子,其聚合度的分布特征符合泊松分布。利用伪反相色谱柱,水-乙腈作为流动相,实现了不同聚合度(n=5~18)TSPnEO的分离。     

Spurious regression due to neglected of non-stationary volatility

This paper examines the effects of permanent changes in the variance of the errors on routine applications of standard t-ratio test in regression models. It is shown the asymptotic distribution of t-ratio test is not invariant to non-stationary in variance, and the phenomenon of spurious regression will occur independently of the structure assumed for these time series. The intuition behind this is that the non-stationary volatility can increase persistency in the level of regression errors, which then leads to spurious correlation. Monte Carlo experiment evidence indicates that, in contrast to the broken level/trend case, the presence of spurious relationship critically depends on the location and magnitude of changes, regardless of the sample size. Finally, some real data sets from the Shanghai stock database are reported for illustration.     

Electrochemical aptasensor for the cancer biomarker CEA based on aptamer induced current due to formation of molybdophosphate

The authors describe a method for signal amplification in electrochemical aptasensors. It is based on the induction of an increased electrochemical current by the aptamer captured on a glassy carbon electrode (GCE). The phosphate groups on the aptamer backbone are brought to reaction with added molybdate to form a redox-active molybdophosphate precipitate on the surface of the GCE that generates a strong electrochemical current. To further enhance sensitivity, gold nanorods (GNRs) were selected as a support for the immobilization of aptamers. The aptasensor was applied to the determination of the cancer biomarker carcinoembryonic antigen (CEA) in a sandwich format. Antibody against CEA, CEA (antigen) and GNRs modified with CEA aptamer  were sequentially captured on the GCE. The resulting aptasensor, best operated at a voltage as low as 0.18 V vs. Ag/AgCl, is highly sensitive and has a wide linear range that extends from 0.1 pg·mL^?1 to 10 ng·mL^?1 of CEA. This amplification strategy uses an aptamer as both the recognition probe and signal probe and therefore simplifies signal transduction. Conceivably, this detection scheme may be adapted to numerous other electrochemical bioassays if respective antibodies and aptamers are available.

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Graphical abstract Schematic presentation of an electrochemical aptasensor based on aptamer induced electrochemical current for the detection of cancer biomarker carcinoembryonic antigen (CEA). Gold nanorods (GNR) are chosen for the immobilization of aptamers to increase the loading of aptamers.

     

Synthesis of sulfonamides from azoles and sodium sulfinates at ambient temperature

NBS or NIS mediated direct SN bond formation between azoles and sodium sulfinates is described. The reaction shows good substrate scope and tolerates a wide range of functionalities in both azoles and sodium sulfinate substrates. Pyrazoles are also suitable for this method, various 4-halopyrazoles derivatives were obtained by using N-halosuccinimide (NXS) as the halogen source.     

Study of quasi-solid electrolyte in dye-sensitized solar cells using surfactant as pore-forming materials in TiO<Subscript>2</Subscript> photoelectrodes

A novel polymer gel electrolyte was used to improve the performance and long-term stability in dye-sensitized solar cells (DSSCs). The polymer gel electrolyte (PGE) was prepared by mixing 5 wt% poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and 2 % TiO₂ nanoparticles. The conductivity of PGE with P25 reached 9.98 × 10^?3 S/cm, which increased by 34.9 % compared with 7.40 × 10^?3 S/cm of PGE without P25, and the diffusion coefficient was also increased by 19.0 %. Different photoelectrodes were obtained by using three kinds of surfactants (cetylamine, octadecylamine, and P123) as pore-forming materials, and their morphologies were contrasted through scanning electron microscopy (SEM). The results showed that gel electrolyte can increase the short-circuit current density (J _sc) from 11.01 to 12.99 mA/cm² in DSSCs. Moreover, unlike the liquid electrolyte, the gel electrolyte is more conducive to the TiO₂ photoelectrodes with larger pores. In conclusion, the efficiency of DSSC with gel electrolyte and P123 as pore-forming material was 6.73 %, which was 12 % higher than the liquid electrolyte in the same test condition. In addition, the sealed gel electrolyte DSSCs showed better stability than did liquid electrolyte DSSCs during nearly 600 h.     

Invariant tori and unboundedness for second order differential equations with asymmetric nonlinearities depending on the derivatives

In this paper, the boundedness and unboundedness of solutions of the oscillator

x^″+ax⁺−bx⁻+φ(x)ψ(x^′)+f(x)+g(x^′)=p(t)$x^{″}+a{x}^{+}-b{x}^{-}+\phi \left(x\right)\psi \left(x^{\prime }\right)+f\left(x\right)+g\left(x^{\prime }\right)=p\left(t\right)$

基于格论的网络结构及其相关性质

通过引入零元和单位元的概念将网络图形结构转化成格结构,证明了加入零元和单位元的网络图形可以在给定的偏序关系下构成格,进而给出了基于格论的网络图形结构的相关性质.     

Doubly heavy baryon production at γγ collider

The inclusive production of doubly heavy baryons Ξ_cc${\Xi }_{cc}$ and Ξ_bb${\Xi }_{bb}$ at γγ collider is investigated. It is found that the contribution from the heavy quark pair QQ in color triplet and color sextet are important.     

Z boson as “the standard candle” for high-precision W boson physics at LHC

In this paper we propose a strategy for measuring the inclusive W boson production processes at LHC. This strategy exploits simultaneously the unique flexibility of the LHC collider in running variable beam particle species at variable beam energies, and the configuration flexibility of the LHC detectors. We propose their concrete settings for a precision measurement of the standard model parameters. These dedicated settings optimise the use of the Z boson and Drell–Yan-pair production processes as “the standard reference candles”. The presented strategy allows one to factorise and to directly measure those of the QCD effects that affect differently the W and Z production processes. It reduces to a level of the impact of uncertainties in the partonic distribution functions (PDFs) and in the transverse momentum of the quarks on the measurement precision. Last but not the least, it reduces by a factor of 10 the impact of systematic measurement errors, such as the energy scale and the measurement resolution, on the W boson production observables.     

From controllable attached isolation moieties to possibly highly efficient nonlinear optical main-chain polyurethanes containing indole-based chromophores

For the first time, the indole-based NLO chromophores were embedded into the polymer main chain, and different isolation groups were attached to their donor side with the efforts of adjusting the NLO properties of the resultant main-chain polyurethanes, according to the site isolation principle. Thanks to the main-chain structure and the advantages of the indole-based chromophores, all the polymers show excellent transparency, good processability, thermal stability, and relatively good NLO effects. The tested NLO properties of the polymers demonstrate that there is a suitable isolation group present for the sulfonyl-based chromophore to boost its microscopic beta value to a possibly higher macroscopic NLO property efficiently.