Fabrication of Sensitive Membrane Electrodes and their Application in Electrochemical Quantification of Ibandronate in Dosage Form

A new, highly selective, simple and accurate method was adopted and validated for the direct quantification of ibandronate sodium monohydrate (IBN) in tablets using sensitive polyvinyl chloride membrane electrodes. Three membranes were fabricated using dibutyl sebacate, nitrophenyl octyl ether and dioctyl phthalate. The fabricated electrodes showed fast response, capability of application in wide pH range and direct determination of IBN in turbid solutions. The most important advantage of the proposed analytical method is that it successfully allows direct determination of IBN in dosage form. The proposed analytical methodology can be applied for the direct quantification of IBN in pharmaceutical formulations.     

An in situ STM and DTS study of the extremely pure [EMIM]FAP/Au(111) interface

Herein the structure of the interfacial layer between the air- and water-stable ionic liquid 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([EMIM]FAP) and Au(111) is investigated using in situ scanning tunneling microscopy (STM), distance tunneling spectroscopy (DTS) and cyclic voltammetry (CV) measurements. The in situ STM measurements reveal that structured interfacial layers can be probed in both cathodic and anodic regimes at the IL/Au(111) interface. The structure of these layers is dependent on the applied electrode potential, the number of subsequent STM scans and the scan rate. Furthermore, first DTS results show that the tunneling barrier during the 1st STM scan does not seem to change significantly in the cathodic potential regime between the ocp (-0.2 V) and -2.0 V.     

Free-standing aluminium nanowire architectures made in an ionic liquid

We report on the electrochemical synthesis of free‐standing aluminium nanowire architectures through a template‐assisted electrodeposition technique. For this purpose, nuclear track‐etched polycarbonate membranes were employed as templates. One side of the template was sputtered with a thin gold film to serve as a working electrode. Subsequently the nanowires were made in the ionic liquid 1‐ethyl‐3‐methylimidazolium chloride ([EMIm]Cl)/AlCl₃ (40/60 mol %) under potentiostatic conditions. Two different electrodeposition procedures were employed to fabricate strongly adherent Al nanowire structures on an electrodeposited Al layer. In the first procedure, electrodeposition simultaneously occurs along the pores of the template and on the Au‐sputtered side of the template. In the second procedure, electrodeposition takes place in two different steps: first a thick supporting film of Al is deposited on the sputtered side of the membrane and second Al nanowires are grown within the pores. After chemical dissolution of the membrane in dichloromethane, an aluminium foil of a controlled thickness with a three‐dimensional nanowire structure on one side was obtained. Different nanowire architectures, such as free‐standing nanowires, vertically aligned tree‐shaped arrays, and bunched nanowire films, were obtained. Such nanowire architectures are of particular interest for applications in Li‐ion micro‐batteries.     

Photoacoustic diagnosis of human teeth using interferometric detection scheme

We have investigated the mechanical and acoustic properties of human teeth using the laser generation of surface acoustic wave (SAW) technique. The materials investigated included normal and decayed teeth, which have similar grain sizes and different thicknesses. The tissue responds to the laser-induced stress by thermoelastic expansion. The informative features of this method allow one to determine sample thermal, optical, and acoustical properties that depend on the peculiarities of the sample compositional structure. An interferometric detection experimental scheme is applied for detection generated SAW pulses. The surface displacement curves shape of normal and decayed human teeth are shown. The dispersion curves for SAW pulses were determined by Fourier analysis. The result is an almost linear dependence of SAW velocity on frequency for a normal tooth, the magnitude of the thermoelastic expansion of the normal tooth reaches its peak at 0.344 μs, a SAW phase velocity of 2500 ms^?1 between 0.0008 and 5 MHz was determined. For abnormal teeth, the magnitude of thermoelastic expansion of the normal tooth reaches its peak at 1.3 μs, the measured velocity was 3225 ms^?1. Due to the inhomogeneity of abnormal teeth perpendicular to the propagation direction, strong differences in their dispersion curves were obtained. The detection of acoustic waves is the basis of photoacoustic methods, which can be used for diagnostic purposes.     

An approach to evaluate the efficiency of γ-ray detectors to determine the radioactivity in environmental samples

This work provides an approach to determine the efficiency of γ-ray detectors with a good accuracy in order to determine the concentrations of either naturally occurring or artificially prepared radionuclides. This approach is based on the efficiency transfer formula (ET), the effective solid angles, the self- absorptions of the source matrix, the attenuation by the source container and the detector housing materials on the detector efficiency. The experimental calibration process was done using radioactive (Cylindrical & Marinelli) sources, in different dimensions, that contain aqueous ¹⁵²Eu radionuclide. The comparison point to a fine agreement between the experimental measured and calculated efficiencies for the (NaI & HPGe) detectors using volumetric radioactive sources.     

Separation of <Superscript>139</Superscript>Ce using solvent extraction technique from La<Subscript>2</Subscript>O<Subscript>3</Subscript> target irradiated by 14.7 MeV protons

The radiochemical separation of no-carrier-added cerium from proton irradiated lanthanum was studied by solvent extraction using DEE, TBP and TPPO, the latter reagent being employed for the first time for separation of radiocerium from bulk of lanthanum. Distribution coefficients of cerium and lanthanum were investigated as a function of equilibrium time and concentration of HNO₃. A mixture of 0.05M K₂Cr₂O₇ and 0.1M H₂SO₄ was used as an oxidizing agent to improve the separation efficiency of cerium. A comparative study of the three extractants released that DEE is the best for separation of cerium from bulk of lanthanum oxide. The target was prepared by pressing. The production of ¹³⁹Ce of high radionuclidic purity and chemical purity via irradiation of lanthanum oxide target at MGC-20 cyclotron with protons of energy 14.5 MeV is described. The experimental yield was found to be 153 kBq/μA·h.