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A sensitive procedure has been developed for the kinetic-photometric determination of copper(II) in natural non-saline and saline waters by flow-injection analysis. The procedure is based on hydroquinone oxidation by hydrogen peroxide in the presence of copper(II) trace concentrations. An alternative scheme of copper(II) determination has been proposed, which provides the elimination of the high background signal associated with non-catalytic reactions. The procedure based on the alterative scheme has lower detection limit of 0.16 µg/L and a wide analytical range of 0.5-20 µg/L copper. The characteristics of catalytic reaction rates in two procedures are compared. The duration of single analysis does not exceed 6 min. Keywords: flow injection analysis, photometric determination of copper(II), hydroquinone, hydrogen peroxide, analysis of natural water DOI: 10.1134/S1061934813010097, Copper(II) is one of the main industrial contaminants of natural waters. It can be present in water in the hydrated state as complexes with inorganic and organic ligands or can [...]

Abstract: Integrated heterostructures exhibiting nanocolumnar morphology of the InxGa1 - xN/Si(111) film are grown on a single-crystal silicon substrate (c-Si(111)) and a substrate with a nanoporous buffer sublayer (por-Si) by molecular-beam epitaxy with the plasma activation of nitrogen. Using a complex of structural and microscopic methods of analysis, it is shown that the growth of InxGa1 - xN nanocolumns on a nanoporous buffer layer offers a number of advantages over growth on c-Si. The por-Si substrate predetermines the preferential orientation of the growth of InxGa1 - xN nanocolumns closer to the Si(111) orientation direction and makes it possible to produce InxGa1 - xN nanocolumns with a higher degree of crystallographic uniformity and with a nanocolumn lateral size of ~40 nm unified over the entire surface. The growth of InxGa1 - xN nanocolumns on a por-Si layer yields a decrease in the strain components εxx and εzz and in the density of edge and screw dislocations compared to the corresponding parameters for InxGa1 - xN nanocolumns grown on c-Si. The InxGa1 - xN nanocolumnar layer fabricated on por-Si exhibits a 20% higher charge-carrier concentration compared to the layer grown on c-Si as well as a higher intensity of the photoluminescence quantum yield (+25%). [ABSTRACT FROM AUTHOR]

The properties of epitaxial GaInP alloys with an ordered arrangement of atoms in the crystal lattice are studied by a number of spectroscopic methods. The alloys are grown by metal-organic chemical vapor deposition onto single-crystal GaAs(100) substrates. It is shown that, under conditions of the coherent growth of an ordered GaInP alloy on a GaAs(100) substrate, atomic ordering results in radical modifications of the optical properties of the semiconductor compared to the properties of disordered alloys. Among these modifications are a decrease in the band gap and an increase in the luminescence intensity. From the data of dispersion analysis of the infrared dispersion spectra and from ultraviolet spectroscopy data obtained in the transmittance-reflection mode of measurements, the basic optical characteristics, specifically, the dispersion of the refractive index and the high-frequency permittivity of GaInP alloys with ordering are determined. All of the experimental data are in good agreement with the developed theoretical concepts. [ABSTRACT FROM AUTHOR]

The properties of epitaxial GaInP alloys with an ordered arrangement of atoms in the crystal lattice are studied by a number of structural and microscopic methods. The alloys are grown by metal-organic chemical vapor deposition onto single-crystal GaAs(100) substrates. It is shown that, under conditions for the coherent growth of an ordered GaInP alloy on a GaAs(100) substrate, atomic ordering results in radical modifications of the structural properties of the semiconductor compared to the properties of disordered alloys. Among these modifications are a change in the crystal-lattice parameter and, as a consequence, lowering of the crystal symmetry and the formation of two different types of surface nanorelief. With consideration for elastic strains, the parameters of GaInP alloys with ordering as functions of the order parameter are calculated for the first time. It is shown that all experimental data are in good agreement with the developed theoretical concepts. [ABSTRACT FROM AUTHOR]

Recombinant DNA containing sequences of HCV NS4 protein was expressed in Escherichia coli cells. Six hybridoma clones producing monoclonal antibodies (MAB) to recombinant NS4 protein (rNS4), aa 1677-1756, were developed. Mapping with a panel of 33 peptides and reciprocal competitive EIA have shown that MAB obtained revealed five antigen determinants, not described earlier: MAB 3F11 and 3F12-one genotype-independent epitope of NS4A (aa 1700-1707) common for genotypes 1, 2 and 3; MAB 1D11-genotype-independent epitope (aa 1713-1728) and MAB 1D3-genotype (subtype 1b)-specific epitope of NS4B (aa 1711-1731); MAB 6B11 and C1-two conformation-dependent determinants in 5-1-1 region. These data indicate that the 5-1-1 region of NS4 protein has a complex antigenic structure and contains at least eight epitopes, including five, revealed in the present work. MAB obtained recognized native viral protein in the cytoplasm of liver cells of patients with chronic hepatitis C. The positive rates of the immunostaining for NS4 antigen using MAB 6B11, 1D11 and 3F12 were 64, 59 and 50%, respectively. It was found that 6B11 MAB to a conformation-dependent epitope much more actively interacts with native NS4 than with the recombinant protein to which MAB was developed. The epitope recognized by 6B11 MAB is highly immunogenic since it induces the B-cell response in all patients investigated with identified anti-NS4 antibodies in blood serum. The MAB panel obtained in this study may become a useful tool for the diagnostic purposes, for the investigation of NS4B function and for the host-viral interactions at the cell level.

A set of 150 synthetic peptides spanning the proteins NS3-NS4-NS5 of the hepatitis C virus (HCV) was synthesized and tested with a panel of 20 sera obtained from HCV-infected patients. Of 62 peptides prepared from the NS3 region, none exhibited strong antigenic reactivity. Rather, five peptides from this region demonstrated specific reactivity with only 5-10% of anti-HVC-positive sera. Nonetheless, it is well known that the NS3 region contains strong antigenic epitopes. These epitopes appear to be modeled in a functionally active manner with recombinant proteins and cannot be mimicked properly with short synthetic peptides. This finding suggests that the major NS3 antigenic epitopes are conformationally dependent. Seven of 20 peptides prepared from the NS4 region were immunoreactive. Five peptides from this region demonstrated very strong HCV-specific antigenic reactivity. Four of the five peptides belong to the recognized immunoreactive 5-1-1 region located inside the C100-3 antigen. One peptide demonstrating immunoreactivity with approximately 90% of anti-HCV-positive sera was found outside the C100-3 region at the C-terminal part of the NS4 protein. Of 68 peptides synthesized from the NS5 protein, 30 were immunoreactive. Six of the 30 demonstrated immunoreactivity with 35-50% of anti-HCV-positive sera. Thus, the NS4 and NS5 regions of the HCV polyprotein contain a large number of specific, broadly reactive, linear antigenic epitopes. The highly antigenic reactivity of the NS5 region suggests that this protein may have significant diagnostic potential.