Assessment of 210Po and 210Pb by moss biomonitoring technique in Thrace region of Turkey

Journal of Radioanalytical and Nuclear Chemistry - This study presents the first data of 210Po and 210Pb activity concentrations using moss species Hypnum cupressiforme from Thrace region, the...     

Electronic and optical properties of black phosphorus doped with Au,Sn and I atoms

In this study, the electronic and the optical properties of monolayer black phosphorus (BP) doped with Gold (Au), Tin (Sn) and Iodine (I) atoms have been investigated by the density-functional theory (DFT) method. In the calculations, the electronic and the optical properties of monolayer BP have been substantially changed with doping. Monolayer BP has a narrow bandgap as 0.85 eV, BP doped with these atoms, results in a metallic behaviour and nearly spin gapless band gap behaviour. The dielectric constant of BP which shows anisotropic optical properties due to different edge states as zigzag and armchair has been changed with doping especially with Au.     

Temporal changes of atmospheric deposition of major and trace elements in European Turkey,Thrace region

Journal of Radioanalytical and Nuclear Chemistry - In the present study, the actual levels and temporal changes of 34 major and trace elements were examined in 44 moss samples Hypnum cuppressiforme...     

Existence and iterative approximation of solutions of generalized mixed quasi-variational-like inequality problem in Banach spaces

In this paper, some existence theorems for the mixed quasi-variational-like inequalities problem in a reflexive Banach space are established. The auxiliary principle technique is used to suggest a novel and innovative iterative algorithm for computing the approximate solution for the mixed quasi-variational-like inequalities problem. Consequently, not only the existence of theorems of the mixed quasi-variational-like inequalities is shown, but also the convergence of iterative sequences generated by the algorithm is also proven. The results proved in this paper represent an improvement of previously known results.     

Existence and stability of iterative algorithms for the system of nonlinear quasi-mixed equilibrium problems

In this paper, we consider the system of nonlinear quasi-mixed equilibrium problems. The existence theorems of solutions of such problems are provided by considering the limit point of an iterative algorithm. This means, we not only give the conditions for the existence theorems of the presented problems but also provide the algorithm to find such solutions. Moreover, the stability of such an algorithm is also discussed. The results presented in this paper are more general, and may be viewed as an extension, refinement and improvement of the previously known results in the literature.     

A resolvent operator technique for approximate solving of generalized system mixed variational inequality and fixed point problems

The main aim of this work is to use the resolvent operator technique to find the common solutions for a generalized system of relaxed cocoercive mixed variational inequality problems and fixed point problems for Lipschitz mappings in Hilbert spaces. An example of applying the main result is also given. The results obtained in this work may be viewed as an extension, refinement and improvement of the previously known results.     

Existence and algorithm of solutions for general set-valued Noor variational inequalities with relaxed (μ,ν)-cocoercive operators in Hilbert spaces

The purpose of this paper is to suggest and analyze a number of iterative algorithms for solving the generalized set-valued variational inequalities in the sense of Noor in Hilbert spaces. Moreover, we show some relationships between the generalized set-valued variational inequality problem in the sense of Noor and the generalized set-valued Wiener-Hopf equations involving continuous operator. Consequently, by using the equivalence, we also establish some methods for finding the solutions of generalized set-valued Wiener-Hopf equations involving continuous operator. Our results can be viewed as a refinement and improvement of the previously known results for variational inequality theory.     

Comparison of sample preparation procedures for the determination of trace heavy metals in house dust, tobacco and tea samples by atomic absorption spectrometry

The effect of wet ashing, dry ashing and microwave procedure for the determination of trace metal levels was investigated in house dust, tobacco and tea samples by atomic absorption spectrometry. The study of sample preparation procedures showed that the microwave method was the best. The recovery of trace metals was very good and precision and accuracy were compatible with standard reference material. The relative standard deviations for all measured metal concentrations were lower than 10%. The digestions of HNO3/H2SO4/HClO4 (4: 1: 1) mixture for house dust, HNO3/H2SO4/H2O2 (2: 2: 2) mixture for tea and HNO3/H2O2 (4: 2) mixture for tobacco were very efficient.     

The Mechanism of Sugar C−H Bond Oxidation by a Flavoprotein Oxidase Occurs by a Hydride Transfer Before Proton Abstraction

Understanding the reaction mechanism underlying the functionalization of C−H bonds by an enzymatic process is one of the most challenging issues in catalysis. Here, combined approaches using density functional theory (DFT) analysis and transient kinetics were employed to investigate the reaction mechanism of C−H bond oxidation in d -glucose, catalyzed by the enzyme pyranose 2-oxidase (P2O). Unlike the mechanisms that have been conventionally proposed, our findings show that the first step of the C−H bond oxidation reaction is a hydride transfer from the C2 position of d -glucose to N5 of the flavin to generate a protonated ketone sugar intermediate. The proton is then transferred from the protonated ketone intermediate to a conserved residue, His548. The results show for the first time how specific interactions around the sugar binding site promote the hydride transfer and formation of the protonated ketone intermediate. The DFT results are also consistent with experimental results including the enthalpy of activation obtained from Eyring plots, as well as the results of kinetic isotope effect and site-directed mutagenesis studies. The mechanistic model obtained from this work may also be relevant to other reactions of various flavoenzyme oxidases that are generally used as biocatalysts in biotechnology applications.