Quantum Coherence and Degree of Mixedness for a System of Two Superconducting Qubits Under Decohe\rence Conditions

Journal of Russian Laser Research - In this work, we study quantum coherence, the degree of mixedness, and total quantum correlation in two interacting superconducting charge qubits (SCQs) in both...     

On a boundary value problem for a p‐Dirac equation

The p‐Laplace equation is a nonlinear generalization of the Laplace equation. This generalization is often used as a model problem for special types of nonlinearities. The p‐Laplace equation can be seen as a bridge between very general nonlinear equations and the linear Laplace equation. The aim of this paper is to solve the p‐Laplace equation for 1 < p < 2 and to find strong solutions. The idea is to apply a hypercomplex integral operator and spatial function theoretic methods to transform the p‐Laplace equation into the p‐Dirac equation. This equation will be solved iteratively by using a fixed‐point theorem. Applying operator‐theoretical methods for the p‐Dirac equation and p‐Laplace equation, the existence and uniqueness of solutions in certain Sobolev spaces will be proved. Copyright © 2016 John Wiley & Sons, Ltd.     

Multivariate statistical design optimization for ultrasonic-assisted restricted access supramolecular solvent-based liquid phase microextraction of quercetin in food samples

In this method, quercetin as a flavonoid has been extracted, preconcentrated and determined by using ultrasonic-assisted restricted access supramolecular solvent-based liquid phase microextraction method in food samples. The quercetin concentration in extraction phase was determinated by UV–visible spectrophotometer which has microsampling cuvette. Multivariate statistical design approach was used to optimize the analytical variables including the pH, ratio of restricted access solvent components, volume of restricted access solvent, ultrasonication and centrifugation times. The analytical performance values of the developed method including limit of detection, limit of quantification, preconcentration factor and relative standard deviation (10 replicates of 10–5 M of quercetin solution) were found as 2.98, 9.93 μg L^?1, 30 and 6.3%, respectively. The method provides important advantages such as use of minimum volume of organic solvents, simple and economical operation and easy optimization via multivariate statistical design approach. The developed procedure was validated with four food samples, and acceptable recoveries (87–104%) were achieved.     

Preparation and characterization of cationic poly vinyl alcohol with a low degree of substitution

The cationization of polymers has been regarded as an effective method to improve their performance for various applications. In this work, the cationization of poly vinyl alcohol (PVA) was investigated under different conditions, i.e., various glycidyl-trimethylammonium chloride (GTMAC) to PVA ratios, reaction temperatures, times, PVA and NaOH concentrations and solvent compositions. The results showed that the overall efficiency of the cationic modification was rather low, which was due to the hydrolysis of both GTMAC and cationic-modified PVA (CPVA) under the strong alkaline conditions employed. The results also showed that the optimum GTMAC/PVA ratio depended on the solvent composition. The cationization was confirmed by means of ¹H NMR and FTIR analyses. The maximum efficiency in water was obtained under the conditions of 95 °C, 1 h, 0.5 (mol) GTMAC/PVA ratio, and 5% (mol) NaOH concentration, while that in the ethanol/DMSO mixture (1.25 v/v) was obtained under the conditions of 70 °C, 1 h, 0.5 (mol) GTMAC/PVA ratio, and 5% (mol) NaOH concentration. Additionally, the interaction of CPVAs with a silicon wafer (as a substrate) was determined by employing an atomic force microscope (AFM) in water and air.     

Cytochrome c embraced in sodium dodecyl sulfate nano-micelle as a homogeneous nanostructured peroxidase

A homogeneous nanostructured enzyme (artificial peroxidase, AP) with suitable catalytic efficiency was generated using bovine heart cytochrome c (Cyt c) and sodium dodecyl sulfate nano-micelles in 50?mM phosphate buffer pH 10.5 at 25?°C. The Michaelis?CMenten (K _m) and catalytic rate (k _cat) of the AP were determined to be 21.6?±?1.2???M and 0.474?±?0.013?s^?1, respectively. The catalytic efficiency of the AP was 0.0219?±?0.002???M^?1s^?1, which was 30?±?1.5?% as efficient as the native horseradish peroxidase (HRP). The mean diameter of AP was measured to be 6.4?nm using dynamic light scattering technique. The UV?CVis spectrometry, circular dichroism, surface tension, isothermal titration calorimetric and electrochemistry methods were utilized for additional characterization of the AP. Together our results suggest that the AP generated here can be used in place of HRP in industrial and commercial fields under some extreme conditions.     

Microperoxidase-11/NH2-FSM16 as a H2O2-resistant heterogeneous nanobiocatalyst: a suicide-inactivation study

The catalytic activity of heme peptides is an area of intense investigation. They are utilized for exploring the fine details of structural and functional properties of an active site, and to create minimized and industrial catalysts. The peroxidase activity and kinetics of suicide-inactivation of microperoxidase-11/FSM16 as a heterogeneous nanobiocatalyst in oxidation reaction of guaiacol were studied in the presence of high concentration of hydrogen peroxide (2?mM), as its natural suicide-substrate. The substrate concentration was first-order in relation to aromatic substrate (AH), and the ratio of suicide-substrate (H₂O₂) was kept much higher than the benign substrate (guaiacol). The results of kinetic analysis confirmed a similar mechanism for suicide-peroxide inactivation of horseradish peroxidase (HRP), microperoxidase (MP-11) and MP-11/NH₂-FSM16. Inactivation kinetic parameters, including intact activity of MP-11/NH₂-FSM16, ??_i, and the apparent inactivation rate constant (k _i) were obtained as 0.229?±?0.009?min^?1 and 0.651?±?0.041?min^?1 at [H₂O₂]?=?2.0?mM, respectively, in 5.0?mM phosphate buffer solution (PBS; pH 7.0) at 27?°C. Our results indicated that covalent immobilization of microperoxidase onto NH₂-FSM16 protected the heme group against peroxide inactivation resulting in generation of an efficient peroxide-resistant heterogeneous nanobiocatalyst.     

Microdetermination of collagenase and collagen

A method for the microdetermination of bacterial collagenase activity and different types of collagen is described. The assay can be used in the range of 2–60 μg for type I and from 10 to 60 μg for other types. Interference of other proteins was eliminated, even those that binds the Sirius red dye. The method is sensitive, rapid, and inexpensive in determination of collagen type I in its pure and fibril form and bacterial collagenase activity and its kinetic parameter.     

Photocatalytic degradation of polyhydroxybutyrate films using titanium dioxide nanoparticles as a photocatalyst

Photocatalytic degradation of polyhydroxybutyrate (PHB) polymeric films (30 μm thickness) containing different concentrations of titanium dioxide (TiO₂) nanoparticles under ultraviolet (UV) irradiation (λ_max = 313 nm) has been studied. The activity of TiO₂ (0.001-0.005%) as a photocatalyst was determined by monitoring various functional group indices, weight loss in polymeric films and photodegradation rate constant (k _d) with irradiation time. Photodegradation was found to be highly dependent on the TiO₂ nanoparticles concentration and the UV irradiation time. The rate of PHB sample photodegradation was highest when the concentration of TiO₂ was 0.005% (by weight) and lowest when its concentration was 0.001%.

     

Synthesis and characterization of a novel Brönsted acidic dicationic ionic liquid based on piperazine and its application in the one-pot synthesis of various xanthenes under solvent-free conditions

In this paper, an interesting Brönsted acidic dicationic ionic liquid based on piperazine was prepared via two-step synthesis. The structure of the dicationic ionic liquid (DIL) was confirmed with various techniques including Fourier transform infrared spectroscopy (FT-IR), Proton NMR (¹H NMR), Carbon-13 NMR (¹³C NMR), mass spectroscopy (MS), acid–base titration as well as Hammett acidity function. Catalytic activity of this novel Brönsted acidic DIL was examined in the xanthene synthesis. High yield of product, short reaction time, easily recovery and reusing of the catalyst, and the absence of organic solvents are some of the merits of the developed procedure.