Analysis of a Polynomial System Arising in the Design of an Optical Lattice Filter Useful in Channelization

In this work, we consider design questions for an active optical lattice filter, which is being manufactured at the University of Texas at Dallas, and which has proven to be useful in the signal processing task of RF channelization. The filter can be described by a linear, discrete time state space model. The controlling agents, the gains, are embedded in the matrices intervening in this state space model. Consequently, techniques from linear feedback control theory do not apply. We concentrate on the question of finding real valued gains so that the A matrix of the state space model has a prescribed characteristic polynomial. We find that three of the coefficients can be arbitrarily picked, but that the remaining are constrained by these and the other system parameters. Our techniques use methods from constructive algebraic geometry.     

A nonnegative extension of the affine demand function and equilibrium analysis for multiproduct price competition

We derive a nonnegative extension of the affine demand function for differentiated substitute products from the optimization problem facing a representative consumer whose utility function is quadratic. We show that the extended demand function reduces to a linear program. The linear program has a simple intuitive interpretation in terms of a shifted price vector. We prove the existence and uniqueness of the Bertrand equilibrium in oligopolies consisting of multiproduct firms under the proposed demand function. The equilibrium, available in closed form, coincides with that obtained when allowing negative demands.     

Synchronization of different dimensional chaotic systems with time varying parameters, disturbances and input nonlinearities

In this paper, the problems of robust exponential generalized and robust exponential Q-S chaos synchronization are investigated between different dimensional chaotic systems. We consider the more practical and realistic cases when unknown time varying parameters with uncertainties, environmental disturbances, and nonlinearity of input control signals are present. The adaptive technique is employed to design the appropriate controllers and the validity of the proposed controllers are proved using Lyapunov stability theorem. Furthermore, numerical simulations are performed to show the efficiency of the presented scheme.     

Lauryl sulfate@magnetic graphene oxide nanosorbent for fast methylene blue recovery from aqueous solutions

Lauryl sulfate is utilized to functionalize magnetic graphene oxide (MGOLS) for fast removal of methylene blue (MB) using batch sorption experiments. The effects of different analytical parameters including medium pH, equilibration time, MGOLS dosage, initial MB concentration and temperature on the % MB removal are investigated. Among different isotherm and kinetic models, the experimental data were best fitted to the Langmuir and pseudo-second-order rate equations. The maximum Langmuir loading capacity reaches 624.42?mg g^?1 for MGOLS under optimal conditions. Sorption kinetic of MGOLS is very fast: Approximately 96% of dye extraction was recorded within the first 2?minutes of this sorption process. The sorption mechanism is proposed and the feasibility, thermic and entropic characteristics were evaluated. Sorption and desorption performances of MGOLS are maintained almost constant over five cycles of sorption/desorption. The results concluded MGOLS as an efficient extractor for fast and feasible recovery of MB from aqueous matrices.     

Biocompatible Water Soluble Polyacrylic Acid Coated CdSe/Cu Quantum Dot Conjugates for Biomolecule Detection

Biocompatible polyacrylic acid functionalized CdSe/Cu quantum dot conjugates were synthesized to be used for biomolecules detection. The study results demonstrate the conjugation of the 2.5-3 nm QD with gram negative bacteria with a low detection limit of 28 cfu/ml. The photoluminescence (PL) intensity was correlated to bacterial count, cellular proteins and exopolysaccharides in the tested samples. Confocal Scanning Laser Microscopy (CSLM) images showed significant QD uptake within the cells, both cytoplasm and DNA were the predominant targeted biomolecules, higher fluorescent uptake was shown in gram negative bacteria than that observed for gram positive bacteria. Moreover, PL showed that there was a distinction between live and dead cells as well as gram negative and gram positive cells. Cell viability was not affected even after 6 days (100% viability) rendering it a non-toxic QD. The method is simple and is performed in a single step within approximately 10 min as compared to multi-step protocols for classical microbial count or fluorescent dye staining. All the above results indicate that the CdSe/Cu-PAA QDs are suitable for biomolecule detection, bio-labeling and bioimaging applications.     

Unexpected products from the reaction of chalcones with cyanoguanidine

A new series of unexpected dihydrochalcones DHCs attached with cyanoiminopyrimidine moiety in addition to expected cyanoaminopyrimidines CAMPs were synthesized by efficient and facile method via reaction of cyanoguanidine with chalcone derivatives in the presence of EtONa.     

New Polymer Syntheses Part 60: A Facile Synthetic Route to Polyamides Based on Thieno[2,3-<Emphasis Type="Italic">b</Emphasis>]thiophene and Their Corrosion Inhibition Behavior

Polyamides containing thieno[2,3-b]thiophene moiety were prepared via a simple polycondensation reaction of the diaminothieno[2,3-b]thiophene monomer 1a with different kinds of diacid chlorides (including oxalyl, adipoyl, sebacoyl, isophthaloyl, terephthaloyl, 4,4′-azodibenzoyl, 3,3′-azodibenzoyl, p-phenylene diacryloyl) in the presence of LiCl and NMP as a solvent through lowtemperature solution polycondensation. The chemical structures of model compound and synthesized polyamides were confirmed by FTIR, nuclear magnetic resonance spectroscopy (including ¹H-NMR and ¹³C-NMR) and elemental analysis. In addition, the thermal stability, crystallinity structure and surface morphology of synthesized polyamides were characterized via thermogravametric analysis (TGA), wide-angle X-ray diffraction analysis (WAXD) and scanning electron microscopy (SEM). Also, the corrosion inhibition behavior of selected examples of polyamides was investigated; the inhibitive effect of the investigated polymers for carbon steel in 1.0 mol·L^?1 HCl was studied using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) methods. PDP results displayed that the polyamides containing thieno[2,3-b]thiophene moiety can be as mixed-type inhibitors. The inhibition efficiency (P, %) was found to be in the range from 67.13% to 96.01%. There is an increase in P by the synthesized polymers in comparison to the starting monomer. The adsorption of these polymers was found to obey Langmuir adsorption isotherm.     

Role of Melatonin in Plant Tolerance to Soil Stressors: Salinity,pH and Heavy Metals

Melatonin (MT) is a pleiotropic molecule with diverse and numerous actions both in plants and animals. In plants, MT acts as an excellent promotor of tolerance against abiotic stress situations such as drought, cold, heat, salinity, and chemical pollutants. In all these situations, MT has a stimulating effect on plants, fomenting many changes in biochemical processes and stress-related gene expression. Melatonin plays vital roles as an antioxidant and can work as a free radical scavenger to protect plants from oxidative stress by stabilization cell redox status; however, MT can alleviate the toxic oxygen and nitrogen species. Beyond this, MT stimulates the antioxidant enzymes and augments antioxidants, as well as activates the ascorbate–glutathione (AsA–GSH) cycle to scavenge excess reactive oxygen species (ROS). In this review, we examine the recent data on the capacity of MT to alleviate the effects of common abiotic soil stressors, such as salinity, alkalinity, acidity, and the presence of heavy metals, reinforcing the general metabolism of plants and counteracting harmful agents. An exhaustive analysis of the latest advances in this regard is presented, and possible future applications of MT are discussed.     

Synthesis of heterocyclic compounds via Michael and Hantzsch reactions

Heterocycles represent the largest diversity of organic compounds with signifcant chemical, biomedical, and industrial applications. They exist in numerous natural products, dyes, and as scaffolds in diverse drugs and related pharmaceutically active substances. Substantial attention has been paid to develop various elegant methods to synthesize heterocycles. Among different strategies, Michael and Hantzsch reactions are considered as effective approaches for construction of heterocycles and their corresponding fused derivatives. This review covers this area especially in the last 10 years. The heterocyclic systems reported in this review are classified according to the kind of the heterocyclic systems.     

Synthesis and Anti-Inflammatory Activities of Some Novel S-Pyridyl Glycosides Derivatives

A series of some new acetylated S-glycosides of pyridine-2-thione derivatives, including D-glucose, D-galactose, D-xylose and L-arabinose derivatives were synthesized. Oxidation of some formed S-glycosides derivatives with H₂O₂ afforded the corresponding sulfones. S-Alkylation of pyridine-2-thione derivatives was performed to furnish the S-acyclo deazauridine derivatives. The entire tested compound showed potent anti-inflammatory activity were potent against edema and in the same time inhibited the prostaglandine formation. It is work mention that all the tested compounds showed high safety margin. The structures of the new synthesized compounds have been proved by IR, ¹ HNMR, mass spectra and elemental analysis.