About the stabilization of the dendritic structure of GG brand copper powder

In industry copper powder is recieved under constant current load. Surface roughening occurs during evolution of the dendritic particles. It is suggested to create a new impulse of current equal to the initial current density of 3200 A/m2 in order to obtain uniform structure of the precipitate. Current load was evaluated by the result of chronopotentiometry research of the dynamics of the dendritic precipitate on cylindrical electrode. Four-impulse galvanostatic electrolysis was investigated for the copper powder GG. New current impulse shifts the electrode potential to the cathodic area, crystallization process flows more rapidly.This work was done under financial support from RFBR № 11-03-002296

Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results

The chromosphere is a thin layer of the solar atmosphere that bridges the relatively cool photosphere and the intensely heated transition region and corona. Compressible and incompressible waves propagating through the chromosphere can supply significant amounts of energy to the interface region and corona. In recent years an abundance of high-resolution observations from state-of-the-art facilities have provided new and exciting ways of disentangling the characteristics of oscillatory phenomena propagating through the dynamic chromosphere. Coupled with rapid advancements in magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly investigate the role waves play in supplying energy to sustain chromospheric and coronal heating. Here, we review the recent progress made in characterising, categorising and interpreting oscillations manifesting in the solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review

Forward modeling of standing kink modes in coronal loops. I. Synthetic views

Kink magnetohydrodynamic (MHD) waves are frequently observed in various magnetic structures of the solar atmosphere. They may contribute significantly to coronal heating and could be used as a tool to diagnose the solar plasma. In this study, we synthesize the Fe ix λ171.073 emission of a coronal loop supporting a standing kink MHD mode. The kink MHD wave solution of a plasma cylinder is mapped into a semi-torus structure to simulate a curved coronal loop. We decompose the solution into a quasi-rigid kink motion and a quadrupole term, which dominate the plasma inside and outside of the flux tube, respectively. At the loop edges, the line of sight integrates relatively more ambient plasma, and the background emission becomes significant. The plasma motion associated with the quadrupole term causes spectral line broadening and emission suppression. The periodic intensity suppression will modulate the integrated intensity and the effective loop width, which both exhibit oscillatory variations at half of the kink period. The quadrupole term can be directly observed as a pendular motion at the front view

Genomics and proteomics approaches to the study of cancer-stroma interactions

<p>Abstract</p> <p>Background</p> <p>The development and progression of cancer depend on its genetic characteristics as well as on the interactions with its microenvironment. Understanding these interactions may contribute to diagnostic and prognostic evaluations and to the development of new cancer therapies. Aiming to investigate potential mechanisms by which the tumor microenvironment might contribute to a cancer phenotype, we evaluated soluble paracrine factors produced by stromal and neoplastic cells which may influence proliferation and gene and protein expression.</p> <p>Methods</p> <p>The study was carried out on the epithelial cancer cell line (Hep-2) and fibroblasts isolated from a primary oral cancer. We combined a conditioned-medium technique with subtraction hybridization approach, quantitative PCR and proteomics, in order to evaluate gene and protein expression influenced by soluble paracrine factors produced by stromal and neoplastic cells.</p> <p>Results</p> <p>We observed that conditioned medium from fibroblast cultures (FCM) inhibited proliferation and induced apoptosis in Hep-2 cells. In neoplastic cells, 41 genes and 5 proteins exhibited changes in expression levels in response to FCM and, in fibroblasts, 17 genes and 2 proteins showed down-regulation in response to conditioned medium from Hep-2 cells (HCM). Nine genes were selected and the expression results of 6 down-regulated genes (<it>ARID4A</it>, <it>CALR</it>, <it>GNB2L1</it>, <it>RNF10</it>, <it>SQSTM1</it>, <it>USP9X</it>) were validated by real time PCR.</p> <p>Conclusions</p> <p>A significant and common denominator in the results was the potential induction of signaling changes associated with immune or inflammatory response in the absence of a specific protein.</p

Polyacrylamide gel electrophoresis of soil humic acid fractionated by size-exclusion chromatography and ultrafiltration

A humic acid (HA) from chernozem soil has been fractionated either by size-exclusion chromatography (SEC) on Sephadex G-75 using water, Tris-HCl or 7 M urea as eluents, or by ultrafiltration (UF) in the presence of 7 M urea or water. UF-fractionated HA was classified as 100K (nominal retention size >100 000); 30K (100 000-30 000); 10K (30 000-10 000); 5K (10 000-5000). Several pools from each chromatography and all ultrafiltration retentates were assayed by polyacrylamide gel electrophoresis (PAGE). The results indicate that SEC fractionation gave a better separation of HA on fractions differing in electrophoretic mobility and molecular size (MS), and that apparently SEC is a more feasible technique than UF for soil HA fractionation; nevertheless the UF in 7 M urea solution might be useful for MS evaluation of HA fractions obtained by association SEC-PAGE. PAGE in the presence of denaturing agents can be successfully used for checking the purity of HA fractions obtained by both SEC and UF.The research described in this paper was made possible in part by grant MU000 from the Interna- tional Science Foundation (ISF) and cooperative grant M U 0 3 0 0 between the Russian Government and ISF. The authors also benefitted from the Cooperation Agreement between the Russian Academy of Sciences and the C.S.I.C. and a grant from the Junta de Andalucía for scientific exchanges.Peer Reviewe

Tandem size exclusion chromatography-polyacrylamide gel electrophoresis of humic acids

Humic acids (HAs) from four soils were fractionated by size exclusion chromatography (SEC) on Sephadex G-75. Three fractions were obtained in all humic acids, collected and assayed by polyacrylamide gel electrophoresis (PAGE). The unfractionated HA from each soil was used as reference. Each chromatographic fraction formed one electrophoretic zone corresponding closely to one band of the reference sample with some admixture of the fractions preceding or following. The results indicate that fractionation of HAs by tandem SEC-PAGE can be successfully used for obtaining fractions of reduced polydispersity and different electrophoretic mobilities. Pyrolysis/methylation-gas chromatography-mass spectrometry of the full size preparations of HA and fractions with exactly defined molecular size and electrophoretic mobility showed a different distribution in humic components, mainly lipids, lignin derivatives and N-containing compounds.Peer Reviewe

Thermochemolysis of genetically different soil humic acids and their fractions obtained by tandem size exclusion chromatography-polyacrylamide gel electrophoresis

Humic acids (HA) from soils of very different origin and bioclimatic conditions (podzoluvisol, phasozem, chernozem, and ferralsol) were fractionated by coupling size-exclusion chromatography and polyacrylamide gel electrophoresis (tandem SEC-PAGE). From each HA, three fractions-A, B, and C+D, with different molecular sizes and electrophoretic mobilities-were obtained and analysed by thermochemolysis, the products being identified subsequently by gas chromatography/mass spectrometry. Regardless of HA origin, fraction A contained considerably more n-fatty acids and n-alkanes derived from plant waxes than did fractions B and C+D. Lignins accumulated mainly in fractions B and C+D. These results show that tandem SEC-PAGE allowed the separation of soil HA into fractions enriched in different structural components whose distribution was independent of HA genesis.This work was supported by the travel grants from the Consejo Superior de Investigaciones Cientificas–Russian Academy of Sciences Cooperation Agreement. Part of this reseach has been supported by INTAS (project 01-186) and Russian Foundation for Basic Research (project 04-05-64687-a).Peer Reviewe