We present the results of magnetic properties and entanglement of the distorted diamond chain model for azurite using pure quantum exchange interactions. The magnetic properties and concurrence as a ...measure of pairwise thermal entanglement have been studied by means of variational mean-field like treatment based on Gibbs-Bogoliubov inequality. Such a system can be considered as an approximation of the natural material azurite, Cu
3
(CO
3
)
2
(OH)
2
. For values of exchange parameters, which are taken from experimental results, we study the thermodynamic properties, such as azurite specific heat and magnetic susceptibility. We also have studied the thermal entanglement properties and magnetization plateau of the distorted diamond chain model for azurite.
Hepatitis C virus (HCV) is easily spread among those who share drug injection equipment. Due to the ease of contraction and growing prevalence of HCV in Eastern Europe, the aims of this study focused ...on describing risky injection practices as well as the prevalence of HCV, HIV and hepatitis B virus (HBV) among people who inject drugs (PWID) who were admitted to public and private drug treatment centres in Turkey from 2012 to 2013. Other aims included identifying correlates of needle sharing and HCV infection. Of the 4694 inpatients who ever injected drugs and the 3914 who injected in the past 30 days, nearly all (98%) reported heroin as their drug of choice, the vast majority reported ever sharing a needle (73.4% and 79.3%), and the mean age at first injection was 23 years. Of current PWID, 51.9% were HCV‐positive, 5.9% were HBV‐positive and only 0.34% of lifetime PWID were HIV‐positive. Predictors of increased needle sharing include younger age, being unemployed, having lesser education and reporting heroin as a drug of choice. Significant predictors of HCV infection included being 40 years or older, receiving treatment in the Mediterranean region of Turkey, reporting heroin as a primary substance, a longer duration of drug use and sharing needles. With this information, it is essential to improve access to clean injection equipment in Turkey, to focus on improving education on clean injection practices and to enhance efforts in testing and treating HCV‐positive PWID.
We consider four atoms coupled to each other by Heisenberg like interactions in an external field of electromagnetic radiation. We prepare Schrödinger cat state using the STIRAP and f-STIRAP ...techniques.
A spectral model is constructed for the luminescence of a two-component exciton-activated quantum dot (QD)–spheroidal plasmon nanoparticle (NP) system in a homogeneous external magnetic field in the ...approximation of a dipole electric polarizability tensor of the nanoparticle with dissipation of the exciton energy in the NP taken into account. A tensor representation of the dielectric permeability of the magnetized electron plasma of the metal is used, which is responsible for the formation of the characteristics of the electric field in the spheroid. It is found that with a change in the eccentricity of the spheroid, the luminescence spectrum of the system changes, reflecting the effect of the external magnetic field on both the radiative and the dissipative properties of the binary QD–NP complex.
A spectral model of luminescence of the two-component exciton-activated semiconductor quantum dot (QD) layered plasmon composite nanoparticle (CNP) with a dielectric core and a conductive shell in an ...external magnetic field is constructed, taking into account the inhomogeneity of the quasi-stationary electric field generated by QD in the CNP region, outside the framework of the approximation of the dipole polarizability of the CNP. The tensor formalism of describing the characteristics of the field in each of the layers of the CNP, as well as outside the CNP, is used. It is established that with a change in the structure of the nanocomposite, the parameters of its core or shell layer, the spectral response of the system to external magnetic field action changes. It is shown that the special form of the response is associated with the characteristic magnetic properties of the nanoparticle components acquired (under the action of the field).
This article deals with the quality of water of tributaries of transboundary River Araks. The performed river water research was underpinned by monthly monitoring data for 2004-2007. As a result of ...the research, a general characteristic of water quality by basic quality indices and the contents of common ions were given. The impact sources and water quality formation-determining factors were indicated. Geochemical series of heavy metals streams were made up and studied, and dominating elements indicated. As a result of statistical data analysis, correlation dependence between concentrations of a different parameters was indicated.
The problem of pollution of the catchment area of the Masrik river, located in the basin of lake Sevan, is associated with the gold mining plant in the basin of its Sotk tributary, where ore is mined ...and crushed. Industrial activity changes the natural background of the formation of the quality of various media within the river basin in terms of the heavy me-tals content in them. Geo-ecological studies in areas of mining activity are relevant from the point of view of assessing the level of pollution and environmental quality control. The object is the drainage basin of the Masrik river with the Sotk tributary that flows near the territory of the gold ore plant. The subject of research is heavy metals in various environments ‒ in water, soil, plants, their behaviour, accumulation and transfer. The contents of Cu, Zn, Pb, Cr, Co, Cd and Ni were determined in water samples, floodplain soils and plants collected in the basins of the Sotk and Masrik rivers. The regularity of the prevalence of summer concentrations of copper over spring was established. It is associated with the difference in water flow in the river, when summer low water is characterized by a sharp decrease in the water content of the rivers. Lead is characterized by the predominance of spring concentrations in the upper reaches of the Sotk river and summer concentrations in the lower reaches of the Masrik River basin. This trend can be due to the washout of storm drains in spring in the Sotk River basin, which is characterized by steep banks and accumulation in the summer period in the flat part of the Masrik river. In general, for both seasons, zinc and nickel differ in relatively high concentrations. According to studies, the values of the distribution coefficient of heavy metals in soils showed a dependence on pH level. The distribution coefficients increased with decreasing acidity values. Pb was among the highest coefficients studied, and the minimum values were typical for Cu. The obtained values of the distribution coefficient indicate that copper has a high solubility and, under favourable conditions, passes into the soil solution. High lead coefficients indicate its low solubility and high adsorption in the soil. The results of the trends analysis and revealed patterns confirmed the presence of a high level of copper solubility in the soil, as well as the significant bioavailability of this metal to plants. For lead, trends of low solubility in soil have been found, but on the issue of bioavailability to plants, it exhibits ambiguous behaviour. Nickel, in terms of accumulation of soil–plant migration in the soil, shows the lowest chemical activity
A model for calculating the second-harmonic (SH) intensity at reflection of light from a monolayer of spherical nanoparticles consisting of a dielectric core and a plasmonic shell, which is located ...near the interface between two optically transparent media, is proposed. Nonlinear polarization of the interface created by nanoparticles (a source of the SH) is calculated. It is found that the intensity of the reflected SH increases due to the dipole and quadrupole plasmon resonances in nanoparticles. It is shown that the spectral positions of the SH intensity maxima depend strongly on size particle core and its permittivity.
Stellacyanins are blue (type I) copper glycoproteins that differ from other members of the cupredoxin family in their spectroscopic and electron transfer properties. Until now, stellacyanins have ...eluded structure determination. Here we report the three‐dimensional crystal structure of the 109 amino acid, non‐glycosylated copper binding domain of recombinant cucumber stellacyanin refined to 1.6 Å resolution. The crystallographic R‐value for all 18,488 reflections (σ > 0) between 50–1.6 Å is 0.195. The overall fold is organized in two β‐sheets, both with four β‐strands. Two α‐helices are found in loop regions between β‐strands. The β‐sheets form a β‐sandwich similar to those found in other cupredoxins, but some features differ from proteins such as plastocyanin and azurin in that the β‐barrel is more flattened, there is an extra N‐terminal α‐helix, and the copper binding site is much more solvent accessible. The presence of a disulfide bond at the copper binding end of the protein confirms that cucumber stellacyanin has a phytocyanin‐like fold. The ligands to copper are two histidines, one cysteine, and one glutamine, the latter replacing the methionine typically found in mononuclear blue copper proteins. The Cu‐Gln bond is one of the shortest axial ligand bond distances observed to date in structurally characterized type I copper proteins. The characteristic spectroscopic properties and electron transfer reactivity of stellacyanin, which differ significantly from those of other well‐characterized cupredoxins, can be explained by its more exposed copper site, its distinctive amino acid ligand composition, and its nearly tetrahedral ligand geometry. Surface features on the cucumber stellacyanin molecule that could be involved in interactions with putative redox partners are discussed.
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