光热偏转技术测量Sr_(2-x)Sm_xFeMoO_6材料的热扩散率

采用固体烧结法制备了Sr2-xSmxFeMoO6(x=0,0.03,0.05,0.08,0.10,0.13,0.15,0.20)多晶结构样品,用X射线衍射对材料的结构进行了检测。通过光热偏转技术方法对该材料的热扩散率进行了研究,给出了掺杂比例与材料热扩散率的关系曲线,结果发现Sr2FeMoO6样品随着参杂Sm浓度的增加,结构发生变化的同时,样品的热扩散率也随着波动变化。这与文献[1]中给出的结论有明显不同,从声子、电子、自旋及其相互作用角度揭示了与文献[1]不同的根本原因;并且从x射线和热扩散率两个角度给出了样品Sr2-xSmxFeMoO6结构转变的参杂比例在10—13%的范围,说明光热偏转技术方法是研究参杂镧系元素的双钙钛矿结构和电子参杂效应的可行有效方法。     

Generalized Strang–Fix condition for scattered data quasi-interpolation

Quasi-interpolation is very useful in the study of the approximation theory and its applications, since the method can yield solutions directly and does not require solving any linear system of equations. However, quasi-interpolation is usually discussed only for gridded data in the literature. In this paper we shall introduce a generalized Strang–Fix condition, which is related to nonstationary quasi-interpolation. Based on the discussion of the generalized Strang–Fix condition we shall generalize our quasi-interpolation scheme for multivariate scattered data, too. AMS subject classification 41A63, 41A25, 65D10Zong Min Wu: Supported by NSFC No. 19971017 and NOYG No. 10125102.     

Synthesis of Deuterium Labeled Standards of 1‐Benzylpiperazine,Fenetylline, Nicocodeine and Nicomorphine

Increasingly abused, 1‐benzylpiperazine (BZP), fenetylline, nicocodeine and nicomorphine are central nervous system stimulants with neurotoxic properties. In recent years, many controlled substance analogs (designer drugs) with a large variety of structures have reached illegal markets, making their identification difficult. This work studies the synthesis of BZP‐d₇, fenetylline‐d₄, nicocodeine‐d₄ and nicomorphine‐d₈, as internal standards for use in gas chromatography‐mass spectrometry (GC‐MS) analysis for identification of these controlled substances.     

Transport of biomolecules in asymmetric nanofilter arrays

We propose a theoretical model for describing the electric-field-driven migration of rod-like biomolecules in nanofilters comprising a periodic array of shallow passages connecting deep wells. The electrophoretic migration of the biomolecules is modeled as transport of point-sized Brownian particles, with the orientational degree of freedom captured by an entropy term. Using appropriate projections, the formulation dimensionality is reduced to one physical dimension, requiring minimal computation and making it ideal for device design and optimization. Our formulation is used to assess the effect of slanted well walls on the energy landscape and resulting molecule mobility. Using this approach, we show that asymmetry in the well shape, such as a well with one slanted and one vertical wall, may be used for separation using low-frequency alternating-current fields because the mobility of a biomolecule is different in the two directions of travel. Our results show that, compared to methods using direct-current fields, the proposed method remains effective at higher field strengths and can achieve comparable separation using a significantly shorter device.     

On the Growth and Fixed Points of Solutions of Second Order Differential Equations with Meromorphic Coefficients

In this paper, we investigate the growth and fixed points of solutions and their 1st, 2nd derivatives, differential polynomial of second order linear differential equations with meromorphic coefficients, and obtain that the exponents of convergence of these fixed points are all equal to the order of growth.     

Chemiluminescence immunoassay for cardiac troponin T by using silver nanoparticles functionalized with hemin/G-quadruplex DNAzyme on a glass chip array

The authors describe an array for chemiluminescence (CL) based determination of cardiac troponin T (cTnT), an important cardiovascular disease marker. The tracing tag consists of silver nanoparticles (AgNPs) loaded with guanine-rich DNA sequences and detection antibody in a high numerical ratio. The loaded AgNPs were then reacted with hemin to form a hemin/G-quadruplex DNAzyme. A disposable immunosensor array was fabricated by immobilizing capture antibody on corresponding sensing sites on a glass chip. Once a sandwich immunocomplex is formed on the array, the tracing tag catalyzes the CL reaction of the luminol-p-iodophenol and H₂O₂ system to produce a CL signal, which is collected by a CCD camera. An intuitive CL image is obtained containing all of the spots on the array. Under optimal conditions, the method shows a wide linear range over 4 orders of magnitude (from 0.003 to 270 ng·L^?1), a detection limit down to 84 fg·L^?1, and a throughput as high as 44 tests·h^?1. The results obtained with serum samples are in acceptable agreement with reference values. The AgNP-based tracing tag as well as the immunoassay method shows a promising potential for point-of-care testing for the early clinical diagnosis of cardiovascular disease.

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Graphical abstract Schematic presentation of silver nanoparticles (AgNPs) functionalized with hemin/G-quadruplex DNAzyme for highly sensitive chemiluminescence (CL) immunoassay of cardiac troponin T (cTnT) on a glass chip array.

     

Structure Characterization and Lead Detoxification Effect of Carboxymethylated Melanin Derived from <Emphasis Type="Italic">Lachnum</Emphasis> Sp.

In the present study, an intracellular melanin, named LIM205, was separated from Lachnum YM205 mycelia and was purified on a Sephadex G-15 column. The molecular weight of LIM205 was determined as 522 Da, and its molecular formula was speculated as C₂₈H₁₄N₂O₇S. The possible chemical structure of LIM205 was determined according to the results of Fourier transform infrared (FT-IR), ¹H NMR, ¹³C NMR, and pyrolysis/GC-MS analysis. With the aim to increase its water solubility, its carboxymethylated derivative, named CLIM205, was formed by the substitution of hydrogen atoms in LIM205 with one, two, and three carboxymethylate groups. FT-IR, UV, and ESI-MS analysis demonstrated that the carboxymethylate groups were conjugated onto LIM205. The lead detoxification activities of LIM205 and CLIM205 had also been investigated. In vivo test showed that both LIM205 and CLIM205 reduced the tissue lead concentration, enhanced lead excretion, and reversed lead-induced alterations in superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) concentrations in mice, with CLIM205 showed better efficacy. The study indicates that LIM205 and CLIM205 have significant lead detoxification effect which will contribute to solve related problems.     

Two new eudesmane derivatives from Verbesina virginica

<正>Two new eudesmane derivatives were isolated from the leaves and flowers of Verbesina virginica,along with the known 6-O-β-E -p-coumaroyl-4α-hydroxyeudesmane(1).Their structures were determined as 6-O-β-Z-p-coumaroyl-4α-hydroxyeudesmane(2) and 6-O-α-E-p-coumaroyl-1β-4α-dihydroxyeudesmane(3) by spectroscopic methods.