Characterization and properties of low-linear-density polyethylene/Typha latifolia composites

The characterization of the effects of different sizes and loadings of Typha latifolia on the tensile, thermal, and morphological properties of linear-low-density polyethylene (LLDPE)/T. latifolia composites were evaluated using tensile test, Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy analyses. Results indicated the tensile strength and elongation at break decreased as T. latifolia loading increased. However, T. latifolia fine size (fs) exhibited better tensile properties than coarse size at the same loading in the composite. T. latifolia (15%, fs) recorded higher thermal stability than LLDPE control and other T. latifolia loadings and sizes due to the strong interaction of T. latifolia (15%, fs) in LLDPE matrix as shown in morphology.     

Microwave Irradiation and Glutamic Acid-Assisted Phytotreatment of Tannery and Surgical Industrial Wastewater by Sorghum

We investigated how different doses of microwave irradiation (MR) affect seed germination in Sorghum, including the level of remediation against textile and surgical wastewater (WW) by modulating biochemical and morpho-physiological mechanisms under glutamic acid (GA) application. The experiment was conducted to determine the impact of foliar-applied GA on Sorghum under wastewater conditions. Plants were treated with or without microwave irradiation (30 s, 2.45 GHz), GA (5 and 10 mM), and wastewater (0, 25, 50, and 100). Growth and photosynthetic pigments were significantly decreased in plants only treated with various concentrations of WW. GA significantly improved the plant growth characteristics both in MR-treated and -untreated plants compared with respective controls. HMs stress increased electrolyte leakage (EL), hydrogen peroxide (H₂O₂), and malondialdehyde (MDA) content; however, the GA chelation significantly improved the antioxidant enzymes activities such as ascorbate oxidase (APX), superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) both in MR-treated and -untreated plants under WW stress compared with respective controls. The results suggested that the MR-treated plants accumulate higher levels of HMs under GA addition in comparison to the WW-only-treated and MR-untreated plants. The maximum increase in Cd accumulation was observed in the range of 14–629% in the roots, 15–2964% in the stems, and 26–4020% in the leaves; the accumulation of Cu was 18–2757% in the roots, 15–4506% in the stems, and 23–4605% in the leaves; and the accumulation of Pb was 13–4122% in the roots, 21–3588% in the stems, and 21–4990% in the leaves under 10 mM GA and MR-treated plants. These findings confirmed that MR-treated sorghum plants had a higher capacity for HMs uptake under GA and could be used as a potential candidate for wastewater treatment.     

tert-Butyl(2-oxo-2H-pyran-5-yl)carbamate as the First Chameleon Diene Bearing an Electron-Donating Substituent

The 2(H)-pyran-2-one bearing electron-donating tert-butylcarbamate (BocNH-) group at the 5- position is a “chameleon” diene and undergoes efficient Diels–Alder cycloadditions with alkene dienophiles with both electron-rich and electron-deficient substituents. Cycloadditions afford the 5-substituted bicyclic lactone cycloadducts regardless of the electronic nature of the dienophile. However, cycloadditions with electronically matched electron-deficient dienophiles proceed faster than those with electronically mismatched electron-rich dienophiles.     

Oxonitriles: a grignard addition-acylation route to enamides

[reaction: see text] Sequential addition of three different Grignard reagents and pivaloyl chloride to 3-oxo-1-cyclohexene-1-carbonitrile installs four new bonds to generate a diverse array of cyclic enamides. Remarkably, formation of the C-magnesiated nitrile intermediate is followed by preferential acylation by pivaloyl chloride rather than consumption by an in situ Grignard reagent. Rapid N-acylation of the C-magnesiated nitrile generates an acyl ketenimine that reacts readily with Grignard reagents or a trialkylzincate, effectively assembling highly substituted, cyclic enamides.     

Electrochemical rectification by redox-labeled bioconjugates: molecular building blocks for the construction of biodiodes

In the present work, we describe the properties of a bifunctional redox-labeled bioconjugate at electrode surfaces mediating the electron transfer across the electrode-electrolyte interface. We show that the assembly of ferrocene-labeled streptavidin on biotinylated electrodes results in a reproducible unidirectional current flow in the presence of electron donors in solution. Such rectifying films were built up by spontaneous binding of tetrameric streptavidin molecules to biotin centers immobilized on the electrode surface. Due to the high affinity of biotin to streptavidin, such bifunctional films completely bind any biotinylated compounds. The charge transport between donors in solution and the Au electrode is mediated by the ferrocene moieties, allowing us to develop a molecular rectifier. Our experimental results suggest that such redox-labeled proteins with a high binding capacity constitute a promising alternative to organic compounds used in molecular electronics.     

Electrogenerated chemiluminescence of conjugated polymer films from patterned electrodes

A new phenomenon is presented in which electrogenerated chemiluminescence (ECL) is generated and propagates laterally as self-reinforcing waves as a result of the oxidation of a poly(9,9-dioctylfluorene-co-benzothiadiazole) thin film. In an ordered array of Au electrode posts that act as effective ECL nucleation sites, soliton-like waves were observed to expand from each site and annihilate upon collision with each other. Simulations of the ECL response supported the experimental observations that the ECL waves propagate at a constant speed. A correlated diffusion mechanism involving the correlated motion of ions, injected holes, and solvent molecules is proposed to interpret the experimental data qualitatively. A rapid increase in the diffusion coefficient of these species in the polymer results in a sharp interface between non-oxidized and oxidized polymer phases wherein the electrochemical (EC) oxidation and mass transport of all pertinent species take place. EC oxidation of conjugated polymers of this type has important implications for the understanding of these materials and their modes of operation in EC conjugated polymer devices.     

Studies on the miscibility and effect of the addition of urea to poly(acrylic acid) and poly(sodium styrene sulfonate) blends by dilute solution viscometry method

The miscibility of poly(acrylic acid) (PAA) and poly(sodium styrene sulfonate) (PSSNa), in H₂O was investigated by a dilute solution viscometry method (DSV). The miscibility of the polymer blend was investigated on the basis of the signs of the interaction parameters Δ[b]_m, Δ[η]_m, ΔB and μ. The results from the viscosity method were correlated with the miscibility data obtained for the same blend by Fourier transform infrared and differential scanning calorimetry. These investigation indicated that the examined blend was miscible for all composition ratios examined (w₂ = 0.10, 0.25, 0.50, 0.75, and 0.90).The addition of urea to the polymer mixture H₂O (1)/PAA (2)/PSSNa (3) decreased the miscibility.     

Supramolecular architectures of streptavidin on biotinylated self-assembled monolayers. Tracking biomolecular reorganization after bioconjugation

In this work we have studied the supramolecular bioconjugation of streptavidin (SAv) on biotinylated self-assembled monolayers. By using the quartz crystal microbalance technique with dissipation we were able to follow in real time the biomolecular reorganization within the film. The overall process could be described as an early stage involving a significant increase in surface coverage followed by another stage where the SAv layer slowly reached the asymptotic coverage. Finally, a reorganization process takes place in the bioconjugated film. These results on the kinetics of biomolecular reorganization can be described in terms of the Lifshitz-Slyozov law. These are the first experimental results demonstrating the complexity and the different time scales involved on the bioconjugation of SAv at solid-liquid interfaces. We consider that these findings could have strong implications on the molecular design of biosensing platforms.     

Compressive advection and multi‐component methods for interface‐capturing

This paper develops methods for interface‐capturing in multiphase flows. The main novelties of these methods are as follows: (a) multi‐component modelling that embeds interface structures into the continuity equation; (b) a new family of triangle/tetrahedron finite elements, in particular, the P₁DG‐P₂(linear discontinuous between elements velocity and quadratic continuous pressure); (c) an interface‐capturing scheme based on compressive control volume advection methods and high‐order finite element interpolation methods; (d) a time stepping method that allows use of relatively large time step sizes; and (e) application of anisotropic mesh adaptivity to focus the numerical resolution around the interfaces and other areas of important dynamics. This modelling approach is applied to a series of pure advection problems with interfaces as well as to the simulation of the standard computational fluid dynamics benchmark test cases of a collapsing water column under gravitational forces (in two and three dimensions) and sloshing water in a tank. Two more test cases are undertaken in order to demonstrate the many‐material and compressibility modelling capabilities of the approach. Numerical simulations are performed on coarse unstructured meshes to demonstrate the potential of the methods described here to capture complex dynamics in multiphase flows. Copyright © 2015 John Wiley & Sons, Ltd.     

Complexes of tris(o-phenanthroline)nickel(II) and copper(II) bromide with dithiocarbamates derived from α-amino acids

Complexes of 1,10-o-phenanthroline (o-phen)-Ni^II and Cu^II with dithiocarbamates derived from -amino acids (glycine, phenylalanine, alanine, methionine and tryptophan) were synthesized and characterized by chemical analysis, spectral and thermal studies and by biological screening; the complexes are non-electrolytes. The empirical formula are [Ni(o-phen)₂(aadtc)] and [Cu₂(o-phen)₂(phaladtc)(H₂O)₂Br₂] where, aadtc = glycinyl-, phenylalaninyl-, alaninyl-, methioninyl- and tryptophanyldithiocarbamate and phaladtc = phenylalaninyldithiocarbamate. The structure of these complexes is probably octahedral. Molecular association through hydrogen bonding between the —NH and the carboxylate groups is proposed for the Ni^II complexes. The Cu^II complex is dimeric with the phenylalaninyldithiocarbamate acting as a bridge.