Structure and catalytic activity of metal complexes fixed on carriers. Hydrodehalogenation of p-bromotoluene with chemically bonded hydrogen,catalyzed by immobilized rhodium(II) complexes

The structure of Rh(II) complexes with vigorous ligands immobilized on -aminopropyl-containing silicagel (-AMPS) and polymers containing 3(5)-methyl-pyrazole and imidazole groups, was investigated. It was shown by IR spectroscopy that the ligand surroundings are maintained after application only for the Rh(II) acetate complex. For the acetonitrile and hexafluoroacetylacetonate complexes there is a replacement of the ligands by amino groups of the carrier. [Rh₂(O₂CCH₃)₄] is significantly more active than other metal complexes immobilized on -AMPS in the hydrodehalogenation of p-bromotoluene by transfer of hydrogen from NaBH₄ and propanol-2.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 65–70, January, 1992.     

DNA／聚（3-甲基噻吩）复合膜修饰电极的制备及其应用于研究8-羟基-2＇-脱氧鸟嘌呤核苷的伏安行为及测定

首先通过电聚合方法在玻碳电极表面制备了聚（3-甲基噻吩）（P3MT）修饰膜,然后在一定电位下将DNA分子电沉积到P3MT表面,制备了DNA／（P3MT）复合膜修饰玻碳电极．研究了8-羟基-2’-脱氧鸟嘌呤核苷（8-OH-dG）在该复合膜修饰电极上的伏安行为以及扫描速度、pH值和尿酸对其伏安行为和检测的影响．实验结果表明,该复合膜修饰电极结合了P3MT和DNA两者的优点,使8-OH-dG在复合膜修饰电极上的电化学行为明显改善,而且具有很好的重现性和稳定性．在0．1mol／LpH7．0的磷酸盐缓冲溶液（PBS）中,8-OH-dG的氧化峰电流与其浓度在0．28～4．2μmol／L和4．2～19．6μmol／L两个范围内成良好的线性关系,检出限为56nmol／L（S／N=3）．该研究可以为制备HPLC或毛细管电泳电化学检测器检测8-OH—dG打下一定的基础,因此在检测尿样中8-OH-dG的研究方面具有潜在的应用价值．     

一种新二肟的合成及其电化学行为

修饰电极;一种新二肟的合成及其电化学行为     

The duality between Morrey spaces and its pre-dual spaces characterized by heat kernel

Let L be an elliptic operator, we give arguments about the duality estimate between Morrey spaces and its pre-dual spaces characterized by the heat kernel associated to L that is given in [6],[8].     

Electrochemical Impedance Spectroscopy in the Characterisation and Application of Modified Electrodes for Electrochemical Sensors and Biosensors

Electrochemical impedance spectroscopy is finding increasing use in electrochemical sensors and biosensors, both in their characterisation, including during successive phases of sensor construction, and in application as a quantitative determination technique. Much of the published work continues to make little use of all the information that can be furnished by full physical modelling and analysis of the impedance spectra, and thus does not throw more than a superficial light on the processes occurring. Analysis is often restricted to estimating values of charge transfer resistances without interpretation and ignoring other electrical equivalent circuit components. In this article, the important basics of electrochemical impedance for electrochemical sensors and biosensors are presented, focussing on the necessary electrical circuit elements. This is followed by examples of its use in characterisation and in electroanalytical applications, at the same time demonstrating how fuller use can be made of the information obtained from complete modelling and analysis of the data in the spectra, the values of the circuit components and their physical meaning. The future outlook for electrochemical impedance in the sensing field is discussed.     

Helical solitons in vector modified Korteweg–de Vries equations

We study existence of helical solitons in the vector modified Korteweg–de Vries (mKdV) equations, one of which is integrable, whereas another one is non-integrable. The latter one describes nonlinear waves in various physical systems, including plasma and chains of particles connected by elastic springs. By using the dynamical system methods such as the blow-up near singular points and the construction of invariant manifolds, we construct helical solitons by the efficient shooting method. The helical solitons arise as the result of co-dimension one bifurcation and exist along a curve in the velocity-frequency parameter plane. Examples of helical solitons are constructed numerically for the non-integrable equation and compared with exact solutions in the integrable vector mKdV equation. The stability of helical solitons with respect to small perturbations is confirmed by direct numerical simulations.     

A Runge-Kutta–based WENO reconstruction on moving mesh for compressible fluids

In this paper, we construct a high-order moving mesh method based on total variation diminishing Runge-Kutta and weighted essential nonoscillatory reconstruction for compressible fluid system. Beginning with the integral form of fluid system, we get the semidiscrete system with an arbitrary mesh velocity. We use weighted essential nonoscillatory reconstruction to get the space accuracy on moving meshes, and the time accuracy is obtained by modified Runge-Kutta method; the mesh velocity is determined by moving mesh method. One- and two-dimensional numerical examples are presented to demonstrate the efficient and accurate performance of the scheme.     

Partitioning of Selected Anisole and Veratrole Derivatives between Water and Anionic Surfactant Micelles

The UV absorption spectra of six structurally related derivatives of anisole and veratrole, i.e., anisaldehyde, (E)-anethole, estragole, veratraldehyde, methyleugenol and (E)-methylisoeugenol, were recorded at various concentrations of the anionic surfactants, either sodium lauryl sulfate (SLS) or sodium lauryl ether sulfate (SLES) at T = 298 K. In addition, conductivity and density measurements were made for the SLS and SLES solutions to determine the volumetric properties of the studied surfactants. Next, using the W. Al-Soufi, L. Pińeiro and M. Novo model (APN model) including the pseudo-phase model for micellar solubilization, the values of micelle-water partition coefficients for each perfume-surfactant system were determined. In addition, the relations between the molecular structures of the solute and the head group of the surfactant and the value of the micelle-water partition coefficient as well as the octanol-water one were discussed.     

New Insight into the EC’ Mechanism of Uric Acid Regeneration in the Presence of Ascorbic Acid on a Poly(3,4‐ethylenedioxithiophene) Modified Gold Electrode

A gold electrode surface was functionalized by means of an electropolymerized conductive poly(3,4‐ethylenedioxythiophene) (PEDOT) organic layer. This modified electrode was used for the electrochemical detection of ascorbic (AA) and uric (UA) acids in an aqueous mixture with a selectivity around 340 mV. The electrochemical reactions kinetics were limited by AA diffusion and UA adsorption at the electrode surface, respectively. Following a previous study ([Electrochem Comm. 2011 , 13, 423–425]) cyclic voltammetry was used to provide a better understanding of the EC’ mechanism of regeneration of UA by AA. Experiments particularly showed that allantoin (i. e. the final product of UA oxidation) is not actually involved in the synergic mechanism but rather the oxidized UA product diimine which is adsorbed at the electrode surface.