Solution Properties of Ternary D-Glucose + 1-Ethyl-3-methylimidazolium Ethyl Sulfate + Water Solutions at 298.15 K

The effect of an ionic liquid, 1-ethyl-3-methylimidazolium ethyl sulfate ([EMIm]ESO₄), on the thermophysical properties of aqueous D-glucose solutions including density, viscosity, and electrical conductivity have been investigated at 298.15 K. Using these properties, the apparent molar volumes, V _φ , the viscosity B-coefficients and the molar conductivities, Λ _m, have been computed for the ternary D-glucose + [EMIm]ESO₄+water solutions. The V _φ values were used to calculate the standard partial molar volumes, V_f⁰V_{\phi}^{0}, and transfer volumes, D_trV_f⁰\Delta_{\mathrm{tr}}V_{\phi}^{0}, of D-glucose from water to aqueous ionic liquid solutions. These volumetric parameters, for all the solutions studied, are positive and increase monotonically with increasing the concentration of [EMIm]ESO₄. These observations have been interpreted in terms of the interactions between D-glucose and ionic liquid in the aqueous solution. The viscosity data were analyzed in terms of the Jones-Dole equation to determine the values of the viscosity B-coefficients. The calculated conductometric parameters, the limiting molar conductivities, Λ ₀, the association constants, K _a, and the Walden products, Λ ₀ η, for [EMIm]ESO₄, decrease with increasing concentration of D-glucose. This trend suggests that the ions of an ionic liquid do not have the same hydrodynamic size in the presence of D-glucose molecules (ILs) and consequently provides evidence for the dehydration effect of the ionic liquid in aqueous D-glucose solutions.     

Reverse Homogeneous Liquid–Liquid Extraction as a Miniaturized Method for Extraction of Aflatoxins from Pistachio and Wheat and LC Post-column Derivatization-Fluorescence Detection

A rapid and simple quantitative method for the simultaneous determination of the four aflatoxins (AFs) B1, B2, G1 and G2 was developed using reverse homogeneous liquid–liquid extraction (RHLEE) and HPLC post-column derivatization-fluorescence (HPLC-FL) detection. The method based on the rapid extraction of AFs from a methanolic sample into chloroform after addition of water containing KBr, with a method we called reverse homogeneous liquid–liquid extraction. Recoveries were in the range of 88–125% and the limits of detection were between 0.001–0.042 ng g^?1 for different AFs. Wheat and pistachio were chosen for the analysis of real samples and the method was also successfully applied to a FAPAS^® TEST MATERIAL (T04151).     

Novel,One-Pot,Three-Component,Regioselective Synthesis of Fluorine-Containing Thiazole and Bis-3H-thiazole Derivatives Using Polyvinyl Pyridine as Heterogeneous Catalyst,and Evaluation of Their Antibacterial Activity

A convenient, one-pot, three-component regioselective synthesis of novel 2,2′-(1,4-phenylene)-bis-(3-aryl-2-substituted imino-4-aryl-3H-thiazole) derivatives from 1,4-phenylene diisothiocyanate, aryl amines, and various phenacyl bromide, and also the regioselective synthesis of 3-alkyl-2-(aryl imino)-4-cyclopropyl-5-(2′-fluorophenyl)-thiazole derivatives from alkylisothiocyanate, aryl amines, and 2-bromo-2-(2-fluorophenyl)-1-cyclopropylethanone in the presence of poly-4-vinyl pyridine as heterogenous basic catalyst are described. This efficient method produced the products at room temperature with excellent yields (82–96%). The structures of all products were characterized by spectral and elemental analyses. The antimicrobial activity of the synthesized compounds was evaluated against Salmonella enterica, Micrococcus luteus, Bacillus subtilis, and Pseudomonas aeruginosa.     

Bromination of Some Aromatic Compounds with Potassium Bromide in the Presence of Benzyltriphenylphosphonium Peroxodisulfate

A simple, efficient, and mild method for selective bromination of some activated aromatic compounds using potassium bromide in the presence of benzyltriphenylphosphonium peroxodisulfate in nonaqueous solution is reported. The results obtained revealed good to excellent selectivity between ortho and para positions of phenols and methoxyarenes.     

CuO-CeO2 nanocomposite：A highly efficient recyclable catalyst for the multicomponent synthesis of 4H-benzo[b]pyran derivatives

CuO–CeO2 is reported as a highly efficient and green recyclable catalyst,for the multicomponent synthesis of 4H-benzo[b]pyran derivatives.The catalyst was synthesized by a co-precipitation method and characterized by XRD,BET specific surface area,ESEM and EDS analysis.This synthetic method provides several advantages such as simple work-up procedures,minimal amount of waste generated,short reaction time,and high yields of products.     

Synthesis and fabrication of (1 − x)ZnAl2O4–xSiO2 thin films to be applied as patch antennas

Zinc aluminate compounds have been dispersed in silica matrix prepared by sol-gel method with different compositions for (1 ? x)ZnAl₂O₄–xSiO₂. Continuous stirring of ethylene glycol solution contained zinc nitrate, aluminium nitrate and silicon dioxide to produces gel precursor. Structural and morphological studies of (1 ? x)ZnAl₂O₄–xSiO₂ thin films were examined by field emission scanning electron microscopy (FESEM) and X-ray diffractometer (XRD) analysis. The FESEM images showed the spherical structures with porosity for (1 ? x)ZnAl₂O₄–xSiO₂ thin films. XRD analysis indicated that the crystallite size for (1 ? x)ZnAl₂O₄–xSiO₂ increased from 39.79 to 44.34 nm. Fourier transform infra-red analysis showed that the existence of H₂O molecules and the presence of nitrate group within the samples. Dielectric permittivity (ε _r ) of (1 ? x)ZnAl₂O₄–xSiO₂ samples were measured within frequency range from 1 Hz to 1 MHz. The dielectric permittivity, ε _r decreased as frequency was applied to the sample. The performance of the patch antenna can be measured using return loss analysis. The highest result shows that the patch antenna resonated at frequency 3.46 GHz and gives ?14.25 dB return loss bandwidth.     

Controlling the mechanical properties of poly(L‐lactide– ε‐caprolactone) monofilament sutures by an acetone/water treatment

For monofilament biodegradable sutures fabricated from the L ‐lactide–ε‐caprolactone (75/25) copolymer [P(LLA/CL)], there have been some concerns regarding their mechanical properties, such as the knot‐pull strength and stiffness. This article demonstrates the further potentiality of these sutures through improvements in those properties. With the aim of diminishing the molecular orientation, particularly in the suture surface region, we adopted an expedient method to treat P(LLA/CL) sutures with an acetone/water mixture, using different times and time patterns. The changes in the molecular orientation distributions across the suture cross sections were characterized by the specific index of birefringence measured with an interference microscope. The crystal orientations, knot‐pull strengths, tensile strengths, and bending rigidity were measured. The conformational changes in suture breaking during knot‐pull tests were analyzed with high‐speed‐video observations. Morphological analyses of the fractural surfaces were performed with scanning electron microscopy. The knot‐pull strength tended to rise, in comparison with that of untreated samples, up to a certain treatment time and was accompanied by a minimal decrement of the tensile strength. The knot‐pull strength did not show an increasing trend with further treatment, whereas the tensile strength declined remarkably. The birefringence, crystal orientation, bending rigidity, fractured surface analysis, and high‐speed‐video observations revealed molecular disorientation mainly in the filament outer layers for that particular treatment causing the sutures to be considerably softer. The suture softness played a role in changing the deformation behavior of the knot when a load was applied and caused the knot‐pull strength to rise. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2449–2462, 2002     

Basic Ionic Liquid as Catalyst and Reaction Media for the One‐pot Three‐component Regioselective Synthesis of Various Thiazol‐2‐imine Derivatives

Thiazol‐2‐imine derivatives were synthesized in an easy and efficient route from the regioselective one‐pot three‐component reaction of aryl amine, alkylisothiocyanate, and various α‐haloketones in [omim][OH] basic ionic liquid. Recyclable reaction media, catalyst free, and short reaction times are the main advantages of this protocol. This method produces the products at room temperature in excellent yields (68–96%). Furthermore, the target compound 6b was determined by X‐ray crystallographic analysis.     

A Comprehensive Review on <Emphasis Type="SmallCaps">l</Emphasis>-Asparaginase and Its Applications

l-asparaginase (LA) catalyzes the degradation of asparagine, an essential amino acid for leukemic cells, into ammonia and aspartate. Owing to its ability to inhibit protein biosynthesis in lymphoblasts, LA is used to treat acute lymphoblastic leukemia (ALL). Different isozymes of this enzyme have been isolated from a wide range of organisms, including plants and terrestrial and marine microorganisms. Pieces of information about the three-dimensional structure of l-asparaginase from Escherichia coli and Erwinia sp. have identified residues that are essential for catalytic activity. This review catalogues the major sources of l-asparaginase, the methods of its production through the solid state (SSF) and submerged (SmF) fermentation, purification, and characterization as well as its biological roles. In the same breath, this article explores both the past and present applications of this important enzyme and discusses its future prospects.