The electrochemical behaviors of methylene blue on the surface of nanostructured NiWO4 prepared by coprecipitation method

A simple coprecipitation method was used for preparation of monoclinic nanostructured NiWO₄ from an aqueous solution at a fixed pH and temperature of 7.0 and 80 °C, respectively. The prepared material was characterized by X-ray diffraction, scanning electron microscopy, photoluminescence spectroscopy, and electrochemical measurements. Nano-NiWO₄ was incorporated into a carbon paste electrode and by means of cyclic voltammetry; the electrochemical behavior of methylene blue on the surface of nano-NiWO₄ was investigated. A mechanism on terms of obtained cyclic voltammograms showing one reduction peak and two sequential oxidation peaks was suggested by emphasizing on the stabilizing role of nano-NiWO₄ for semi-methylene blue. A diffusion coefficient of 5.30?×?10^?6 cm²/s was gained for methylene blue.     

Three-Component,One-Pot Synthesis of Benzo[b][1,4]oxazines in Ionic Liquid 1-Butyl-3-methylimidazolium Bromide

Benzo[b][1,4]oxazines have been synthesized in good to excellent yields in the presence of the ionic liquid 1-butyl-3-methylimidazolium bromide [bmim]Br under relatively mild conditions without any added catalyst, The method offers the advantages of good yields and short reaction times, and the ionic liquid can be easily separated from the product and reused.     

Microwave Assisted Synthesis of Dibenzoxazepines

Dibenzo[b,f][1,4]oxazepine derivatives were synthesized in good yields and short reaction times by the reaction of 2‐chlorobenzaldehydes and 2‐aminophenoles in basic conditions under microwave irradiation.     

Uranium recovery from UCF liquid waste by nanoporous MCM-41: breakthrough capacity and elution behavior studies

Adsorption and recovery of uranium by nanoporous MCM-41 from aqueous solutions (synthetic solution and uranium conversion facility liquid waste) were investigated by use of a fixed-bed column (1.2 cm diameter and 3.0 cm height). Adsorption was carried out at flow rates 0.2 and 0.5 mL min^?1, which correspond to retention times of 10 and 6 min. The maximum breakthrough capacity for uranium ions was achieved by use of nanoporous MCM-41 at the optimum pH of 3.6 and flow rate 0.2 mL min^?1 (61.95 μg g^?1). The Thomas and Yan models were applied to the experimental data, by use of linear regression, to determine the characteristics of the column for process design. The breakthrough curves calculated from the models were in good agreement with the experimental data. The elution behavior of uranium on nanoporous MCM-41 was studied with different eluents; the results showed that 0.1 M HCl is good eluent for uranium recovery. The regenerated column could be used in a multitude of adsorption–desorption cycles.     

Contamination of therapeutic human immunoglobulin preparations with apolipoprotein H (β2‐glycoprotein I)

Polyclonal immunoglobulin (Ig) concentrates are important biological medicinal products and the assurance of their quality and safety is crucial. In our present approach we used proteomic methods to check the purity of commercial Ig products of different origin. The experimental setup included nonreducing 2DE or DIGE combined with MALDI‐TOF and the thrombin generation assay, a routine safety test for pharmaceutical Ig preparations, and was complemented by a specific immunoassay. 2DE patterns displayed contaminations with trace amounts of human apolipoprotein H (Apo‐H), transferrin, albumin, and its fragments. In contrast to the latter, Apo‐H is a protein that is active in the coagulation cascade, and thus a potential involvement in thromboembolic events in vivo cannot be excluded. It was found by 2DE and MALDI‐TOF to be a contaminant of several Ig preparations. Spiking experiments of Ig preparations with pure Apo‐H demonstrated an Apo‐H concentration dependent increase in thrombin generation assay values. Traces of Apo‐H are possibly also contributing to unwanted side effects, as already known for factor XIa. The significance of Apo‐H contaminations for these side effects might be verified by detailed analyses of pharmacovigilance data.     

Palladium-catalyzed oxidative C–H bond coupling of indoles and benzaldehydes: a new approach to the synthesis of 3-benzoylindoles

A palladium-catalyzed dehydrogenative acylation of indoles using easily accessible aldehydes as the acyl source is described. This reaction provides a new approach for the synthesis of 3-acylindoles.     

Effect of Process Variable on the Gelation Time of Sulfonated Polyacrylamide Nanocomposite Hydrogel

Among the methods available to reduce water production during oil recovery, injecting a gelling system composed of a polymer and a crosslinker has been widely used. In this study, a Plackett-Burman design was used for screening a large number of factors such as concentrations of polymer, crosslinker, pH, temperature, and presence or absence of NaCl, CaCl₂, MgCl₂, KCl, thiourea, sodium lactate, and nanoclay on the gelation time of sulfonated polyacrylamide nanocomposite hydrogels by rheological tests. Among these factors, temperature, pH, and CaCl₂ concentration were found to have the greatest effect on the gelation time. The effects of these three factors and their interactions on the gelation time were then determined by using central composite design of response surface method. As a result, the interactions of CaCl₂ concentration with temperature and pH were considerably more than the interactions of pH and temperature on the gelation time. At low pH (3 < pH < 7), the gelation time decreased by decrease of pH while at CaCl₂ concentration of 3750–11250 ppm and at 7 < pH < 11, the gelation time increased with the increase of pH. It was found that temperature was the most effective parameter to control the gelation time.     

Cu-based atom transfer radical polymerization of methyl methacrylate using a novel tridentate ligand with mixed donor atoms

This study is aimed at atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) using a novel catalyst. The bis-(2-dodecylsulfanyl-ethyl)-amine (SNS) tridentate ligand with mixed donor atoms was synthesized in high purity using inexpensive reagents and was reacted with copper(I) bromide to produce the CuBr/SNS catalyst. The catalyst mediated living polymerization of MMA yielding polymers with controlled molecular masses and narrow molecular mass distributions (PDI < 1.25). Also, the kinetic plot exhibited a linear increase of ln([M]₀/[M]) versus time, indicating constant concentration of propagating radicals during the polymerization. The products were characterized by ¹H NMR, ¹³C NMR, FT-IR, UV-VIS, GC and elemental analyses (CHNS) and by GPC.     

A Triple Pore Network Model (T-PNM) for Gas Flow Simulation in Fractured,Micro-porous and Meso-porous Media

Transport in Porous Media - In this study, a novel triple pore network model (T-PNM) is introduced which is composed of a single pore network model (PNM) coupled to fractures and micro-porosities....