Controlled Synthesis,Spectral Studies,and Catalytic Activity of Silver and Gold Nanoparticles Biosynthesized Using Ficus sycomorus Leaf Extract

Journal of Applied Spectroscopy - Plant-mediated synthesis of nanoparticles (NPs) is an efficient and safe alternative to the conventional synthetic route. In this study, silver and gold NPs (AgNPs...     

源自天然席夫碱的过渡金属配合物在分光光度法测天然水中的Fe(Ⅲ)的应用

描述了一种新颖、简便的合成含五齿配位基的大环席夫碱配体的方法,制备和表征了该席夫碱的1∶1包合物。用化学和光谱学方法测定了标题配合物的组成,认为在所有配合物中配位金属原子取八面体结构。数据表明:配体起O2N4六齿结构而每个环绕金属原子在八面体环境中。配合物的红外和1H NMR光谱符合中心金属原子的配位结果。用分光光度法测定了配合物的稳定常数。用共轭余量法(CR method)计算了在热分解的不同阶段配合物活化的动力学和热力学参数。此外,用抑菌圈直径法筛选了配体及其金属配合物抑制细菌和真菌的能力。用回收率试验研究了天然螯合配体在不同天然水体中对Fe(Ⅲ)离子配合作用的影响。     

Synthesis, characterization and application of enrofloxacin complexes as thermal stabilizers for rigid poly(vinyl chloride)

Synthesis and characterization of both binary Co(II)- (1), Ni(II)- (2) complexes with enrofloxacin drug (HL(1)) and ternary Co(II)- (3), Ni(II)- (4) complexes in presence of DL-alanine (H(2)L(2)) are reported using physico-chemical techniques. The antimicrobial activity of these complexes has been screened against two gram-positive and two gram-negative bacteria. Antifungal activity against two different fungi has been evaluated and compared with reference drug. All the binary and ternary complexes showed remarkable potential antimicrobial activity higher than the recommended standard agents. Ni(II)-complexes exhibited higher potency as compared to the parent drug against bacterial and fungal strain. In addition, it was of interest to investigate the reported complexes as thermal stabilizers and co-stabilizers for rigid PVC in air at 180 °C. Their high stabilizing efficiency is detected by their high induction period values (T(s)) compared with some of the common reference stabilizers used industrially, such as dibasic lead carbonate (DBLC) and calcium-zinc soap. Blending these complexes with some of the reference stabilizers in different ratios had a synergistic effect on both induction period as it gave better thermal stability and lower extent of discoloration. The stabilizing efficiency is attributed at least partially to the ability of the metal complex stabilizer to be incorporated in the polymeric chains, thus disrupting the chain degradation and replace the labile chlorine atoms on PVC chains by a relatively more s moiety of the inorganic stabilizer. Their amenability to use as a biomedical additives for PVC, has afforded them great potential for various medical applications.     

Inverse Problems of Boundary Value Problems for Annular Vibrating Membranes with Piecewise Smooth Positive Functions in the Boundary Conditions

The asymptotic expansions of the trace of the heat kernel for small positive t, where λ_ν are the eigenvalues of the negative Laplacian in Rⁿ (n=2 or 3), are studied for a general annular bounded domain Ω with a smooth inner boundary ?Ω₁ and a smooth outer boundary ?Ω₂ where a finite number of piecewise smooth Dirichlet, Neumann and Robin boundary conditions on the components Γ _j (j=1,…,m) of ?Ω₁ and on the components of ?Ω₂ are considered such that and and where the coefficients in the Robin boundary conditions are piecewise smooth positive functions. Some applications of Θ (t) for an ideal gas enclosed in the general annular bounded domain Ω are given.     

Flow injection potentiometric sensor for determination of phenylpropanolamine hydrochloride

A new polymeric membrane electrode has been constructed for the determination of phenylpropanolamine hydrochloride. The electrode was prepared by solubilizing the phenylpropanolamine-phosphomolybdate ion associate into a polyvinyl chloride matrix plasticized by dibutylphthalate as a solvent mediator. The electrode showed near-Nernstian response over the concentration range of 1 × 10^?5–1 × 10^?2 M with low detection limit of 6.3 × 10^?6 M. The electrode displays a good selectivity for phenylpropanolamine with respect to a number of common inorganic and organic species. The electrode was successfully applied to the potentiometric determination of phenylpropanolamine ion in its pure state and its pharmaceutical preparation in batch and flow injection conditions.     

A New Jacobi Elliptic Function Expansion Method for Solvinga Nonlinear PDE Describing Pulse Narrowing Nonlinear Transmission Lines

In this article, we apply the first elliptic function equation to find a new kind of solutions of nonlinear partial differential equations (PDEs) based on the homogeneous balance method, the Jacobi elliptic expansion method and the auxiliary equation method. New exact solutions to the Jacobi elliptic functions of a nonlinear PDE describing pulse narrowing nonlinear transmission lines are given with the aid of computer program, e.g. Maple or Mathematica. Based on Kirchhoff's current law and Kirchhoff's voltage law, the given nonlinear PDE has been derived and can be reduced to a nonlinear ordinary differential equation (ODE) using a simple transformation. The given method in this article is straightforward and concise, and can be applied to other nonlinear PDEs in mathematical physics. Further results may be obtained.     

Exact Traveling Wave Solutions for Higher Order Nonlinear Schrödinger Equations in Optics by Using the (G'/G, 1/G)-expansion Method

The propagation of the optical solitons is usually governed by the nonlinear Schrödinger equations. In this article, the two variable (G'/G, 1/G)-expansion method is employed to construct exact traveling wave solutions with parameters of two higher order nonlinear Schrödinger equations describing the propagation of femtosecond pulses in nonlinear optical fibers. When the parameters are replaced by special values, the well-known solitary wave solutions of these equations rediscovered from the traveling waves. Thismethod can be thought of as the generalization of well-known original (G'/G)-expansion method proposed by M. Wang et al. It is shown that the two variable (G'/G, 1/G)-expansion method provides a more powerful mathematical tool for solving many other nonlinear PDEs in mathematical physics.     

New extended auxiliary equation method for finding many new Jacobi elliptic function solutions of three nonlinear Schrödinger equations

In this paper, we construct many new types of Jacobi elliptic function solutions of nonlinear evolution equations using the so-called new extended auxiliary equation method. The effectiveness of this method is demonstrated by applications to three higher order nonlinear evolution equations, namely, the higher order nonlinear Schrödinger equation with derivative non-Kerr nonlinear terms, the higher order dispersive nonlinear Schrödinger equation and the generalized nonlinear Schrödinger equation. The solitary wave solutions and periodic solutions are obtained from the Jacobi elliptic function solutions. Comparing our new results and the well-known results are given.     

Construction of orthonormal wavelets using Kampé de Fériet functions

One of the main aims of this paper is to bridge the gap between two branches of mathematics, special functions and wavelets. This is done by showing how special functions can be used to construct orthonormal wavelet bases in a multiresolution analysis setting. The construction uses hypergeometric functions of one and two variables and a generalization of the latter, known as Kampé de Fériet functions. The mother wavelets constructed by this process are entire functions given by rapidly converging power series that allow easy and fast numerical evaluation. Explicit representation of wavelets facilitates, among other things, the study of the analytic properties of wavelets.

     

Synthesis and structure investigation of the antibiotic amoxicillin complexes of d-block elements

The study of some transition metals (M) and amoxicillin trihydrate (ACT) ligand complexes (M-ACT) that formed in solution involved the spectrophotometric determination of stoichiometric ratios and their stability constants and these ratios were found to be M:ACT = 1:1, 1:2 and 2:1 in some instances. The calculated stability constants of these chelates, under selected optimum conditions, using molar ratio method have values ranging from K(f) = 10(7) to 10(14). These data were confirmed by calculations of their free energy of formation deltaG, which corresponded to their high stabilities. The separated solid complexes were studied using elemental analyses, IR, reflectance spectra, magnetic measurements, mass spectra and thermal analyses (TGA and DTA). The proposed general formulae of these complexes were found to be ML(H2O)w(H2O)x(OH)y(Cl)2, where M = Fe(II), Co(III), w = 0, x = 2, y = 1, z = 0; M = Co(II), w = 0, x = 1, y = 0, z = 1; M = Fe(III), w = 0, x = 1, y = 2, z = 0; M = Ni(II), Cu(II) and Zn(II), w = 2, x = 0, y = 1, z = 0, where w = water of crystallization, x = coordinated water, y = coordinated OH(-) and z = Cl- in the outer sphere of the complex. The IR spectra show a shift of nu(NH) (2968 cm(-1)) to 2984-2999 cm(-1) of imino group of the ligand ACT and the absence of nu(CO) (beta-lactame) band at 1774 cm(-1) and the appearance of the band at 1605-1523 cm(-1) in all complexes suggest that 6,7-enolization takes place before coordination of the ligand to the metal ions. The bands of M-N (at 625-520 cm(-1)) and of M-O (at 889-7550 cm(-1)) proved the bond of N (of amino and imino groups) and O of C-O group of the ligand to the metal ions. The reflectance spectra and room temperature magnetic measurements refer to octahedral complexes of Fe(II) and Fe(III); square planner form of Co(II), reduced Co(III), Ni(II) and Cu(II)-ACT complexes but tetrahedral form of Zn-ACT complex. The thermal degradation of these complexes is confirmed by their mass spectral fragmentation. These data confirmed the proposed structural and general formulae of these complexes.