Synthesis,X‐ray Studies,and Catalytic Efficacy of a Novel Iron Complex Containing an N,O‐Type Bidentate Thiazoline Ligand

The reactions of FeCl₃ · 6H₂O and 2‐(2′‐hydroxyphenyl)‐2‐thiazoline as a bidentate O‐N donor thiazoline ligand (thoz) afford a five‐coordinate Fe^III complex [Fe(thoz)₂Cl] with a distorted square pyramidal configuration. Complex [Fe(thoz)₂Cl] was isolated as air‐stable crystalline solids and fully characterized, including by single‐crystal X‐ray structure analysis. Complex [Fe(thoz)₂Cl] shows very efficient reactivity in the oxidation of sulfides to their corresponding sulfoxides using urea hydrogen peroxide (UHP) as the oxidant at room temperature in air.     

Headspace solvent microextraction A new method applied to the preconcentration of 2-butoxyethanol from aqueous solutions into a single microdrop

A new procedure and experimental setup for the headspace solvent microextraction of volatile organic materials from aqueous sample solutions is described. The extraction occurs by suspending a 3-μl drop of the solvent from the tip of a microsyringe to the headspace of a stirred aqueous sample solution for a preset extraction time. The temperature of the microdrop and the bulk of sample solution should be kept constant at optimized values. The sample analyses were carried out by gas chromatography. The procedure was successfully applied to the extraction and determination of 2-butoxyethanol from content of some color samples used for painting the outer coverage of some machines such as coolers, refrigerator, cloths machine, etc. Parameters such as extraction time, nature of extraction solvent, size of microdrop, sample volume, stirring rate, ionic strength and pH of sample solution were studied and optimized, and the method performance was evaluated.     

Simultaneous determination of theophylline and caffeine by proton magnetic resonance spectroscopy using partial least squares regression techniques.

A 1H-NMR procedure based on an analysis of its data by a multivariate calibration method was conducted for the simultaneous determination of theophylline and caffeine in synthetic and real samples. Partial least squares regression (PLS) was chosen as the calibration method. The methyl signals of theophilline at 3.36 and 3.54 ppm that overlapped with those of caffeine were significant characteristics which were employed in this study for their analyses. The proposed method was successfully applied to recovery studies of theophylline and caffeine from real tablet samples.     

Electrochemical Characterization of In Situ Functionalized Gold Cysteamine Self‐Assembled Monolayer with 4‐Formylphenylboronic Acid for Detection of Dopamine

Functionalization of gold cysteamine (Au? CA) self‐assembled monolayer with 4‐formylphenylboronic acid (BA) via Schiff's base formation, through in situ method to fabricate Au‐CA‐BA electrode is presented and described. The fabricated electrode was used as a novel sensor for accumulation and determination of dopamine (DA). The accumulation of DA as a diol on the topside of Au‐CA‐BA as a Lewis acid, was performed via esterification (Au? CA? BA? DA), and followed for determination of DA. Functionalization, characterization, and determination steps were probed by electrochemical methods like cyclic voltammetry and electrochemical impedance spectroscopy. The data will be presented and discussed from which a new sensor for DA is introduced.     

Band selection of hyperspectral-image based weighted indipendent component analysis

Huge amounts of data in hyperspectral images have been caused to represent approaches for the band selection of these images. In this paper, a new approach based on independent component analysis (ICA) is proposed. The idea of projection pursuit is used to order the bands on the basis of a non-gaussianity distribution. Applying a negentropy function to weight bands is a novel idea that leads to the selection of bands with minimum mutual information (MI) and besides maximum entropy, with respected to the bands selected using other methods.     

Copper(II)-selective fluorimetric bulk optode membrane based on a 1-hydroxy-9,10-anthraquinone derivative having two propenyl arms as a neutral fluorogenic ionophore

A new optical chemical sensor has been developed for the selective determination of copper(II) ions in aqueous solutions. The reversible sensing system was prepared by incorporating 1-hydrpxy-2-(prop-2'-enyl)-4-(prop-2'-enyloxy)-9,10-anthraquinone (AQ) as a neutral Cu2+-selective fluoroionophore in the plasticized PVC membrane with potassium tetrakis(p-chlorophenyl borate) as an anionic additive. The response of the sensor is based on the fluorescence quenching of AQ by Cu2+ ions. At a pH 5.5, the proposed sensor displays a calibration response for Cu2+ over a wide concentration rang of 1.0 x 10(-2) to 1.0 x 10(-6) M, with a relatively fast response of less than 40 s. In addition to high stability and reproducibility, the sensor shows a unique selectivity towards Cu2+ ion with respect to common co-existing cations. The proposed fluorescence optode was applied successfully to the determination of copper(II) in black tea samples.     

The Σ1-provability logic of HA

In this paper we introduce a modal theory ${\mathsf{iH}}_{\sigma }$ which is sound and complete for arithmetical ${\mathrm{\Sigma }}_1$-interpretations in $\mathsf{HA}$, in other words, we will show that ${\mathsf{iH}}_{\sigma }$ is the ${\mathrm{\Sigma }}_1$-provability logic of $\mathsf{HA}$. Moreover we will show that ${\mathsf{iH}}_{\sigma }$ is decidable. As a by-product of these results, we show that $\mathsf{HA}+\square \perp$ has de Jongh property.     

Efficiency analysis in two-stage structures using fuzzy data envelopment analysis

Two-stage data envelopment analysis (TsDEA) models evaluate the performance of a set of production systems in which each system includes two operational stages. Taking into account the internal structures is commonly found in many situations such as seller-buyer supply chain, health care provision and environmental management. Contrary to conventional DEA models as a black-box structure, TsDEA provides further insight into sources of inefficiencies and a more informative basis for performance evaluation. In addition, ignoring the qualitative and imprecise data leads to distorted evaluations, both for the subunits and the system efficiency. We present the fuzzy input and output-oriented TsDEA models to calculate the global and pure technical efficiencies of a system and sub-processes when some data are fuzzy. To this end, we propose a possibilistic programming problem and then convert it into a deterministic interval programming problem using the α-level based method. The proposed method preserves the link between two stages in the sense that the total efficiency of the system is equal to the product of the efficiencies derived from two stages. In addition to the study of technical efficiency, this research includes two further contributions to the ancillary literature; firstly, we minutely discuss the efficiency decompositions to indicate the sources of inefficiency and secondly, we present a method for ranking the efficient units in a fuzzy environment. An empirical illustration is also utilised to show the applicability of the proposed technique.     

Nonlinear optical and structural properties of M@C N endohedrals (M = Li,Ca and Sc,N = 60 and 70)

We have investigated the static (ω = 0) and frequency-dependent nonlinear optical (NLO) properties of the M@C _N endohedrals (M = Li, Ca, Sc, N = 60 and 70) using the SSH (Su–Schrieffer–Heeger) approximation and sum-over-state (SOS) approach. Also, we study the effects of displacement and alkali, alkaline earth and lanthanide metal atoms and type of cage on the hyperpolarisabilities of the M@C _N endohedrals. The hyperpolarisability magnitudes and spectra are in agreement with experiment and the work of others using the SSH approximation. Our results indicate that the cage-type effect on the NLO spectra of M@C _N endohedrals is dramatic. Also, atom type has little effect on the highest peak value. These relationships between the atom and cage type and hyperpolarisability values may be beneficial to experimentalists when designing new NLO materials with large NLO responses.