This research is devoted to the study of the composition and surface morphology of extremely thin ‘spin-on glass’ films (~20–50 nm) doped with Pt and Pd compounds in concentrations depending on the ...ratio of precursors in TEOS-derived sols, their aging time and heat treatment temperature.
Such methods as spectrophotometry in visible and ultraviolet regions, atomic force and scanning microscopy, X-ray reflectometry, X-ray phase analysis and voltammetry were used to study processes of the formation of sols and films based on them.
The authors of this study defined features of sol-gel processes based on acid hydrolysis of TEOS in presence of dopants (Pt and Pd compounds) taken separately and together. It was shown that the combination of two dopants (Pt and Pd compounds) taken in the mole ratio of 1:1 increases catalytic activity of the films towards hydrogen.
•The rate of hydrolysis of Pt, Pd complexes depends on their concentration in the sol.•Sol-gel silica layers doped by metallic Pd & Pt/Pd nanoparticles were obtained at RT.•The equimolar Pt/Pd ratio provides sol high sedimentary and aggregative stability.•Equimolar Pt/Pd ratio provides a high adsorption capacity of the catalytic layer.
Spin-wave transport in a lateral system of microwaveguides coupled to each other through a magnonic crystal structure with a one-dimensional array of holes has been analyzed. Mechanisms of ...controlling a spin-wave signal at the tangential magnetization of the structure have been studied by the micromagnetic simulation and Brillouin spectroscopy. It has been shown that the anisotropy of the shape in region of coupling of spin waves propagating through isolated channels can be effectively changed under the variation of the magnetization angle of the structure, which allows controlling spatial and frequency selective regimes of spin-wave transport. The proposed structure can be used as a functional element of interconnections in planar topologies of magnonic networks and devices for parallel processing of a signal based on them.
The effects of heating and carbonization regimes on the properties of poly(p-phenylene-1,3,4- oxadiazole) fibers and carbon fibers made from them were studied using x-ray, thermal, electrothermal, ...and mass-spectrometric analyses. Structural transformations that changed the fiber system state were responsible for the electrothermal transformations in the polymeric fiber during heat treatment in the low-temperature range up to 400°C
An iterative method for solving the inverse/mixed problem for a multi-element airfoil at low speeds in the framework of the Reynolds averaged Navier–Stokes (RANS) equations, which belongs to the ...class of residual correction methods, is developed. The deformation of the surface of the airfoil elements, decreasing the residual between calculated and target pressure distribution, is determined using the panel method for solving the direct/inverse problem for the same airfoil in an incompressible inviscid flow. A brief description of the methods used is given. Examples of constructing the geometry of the elements of a multi-element airfoil according to a given pressure distribution are shown, demonstrating high rate of convergence of the method (3–4 iterations). High-lift thick (
) laminar airfoil with cruise flap is designed for use in the wing of low-speed aircraft. The wing with this airfoil was tested on a thematic model in the wind tunnel. High values of lift are obtained with a moderate level of profile drag.
Since 2007, the non-indigenous calanoid copepod
Pseudodiaptomus marinus
Sato, 1913 has been increasingly recorded in numerous European sites, spreading at an unexpectedly fast pace over a short ...time-span. This species presents specific biological and behavioural traits which make it of particular interest for ecological and applied research topics. On 29–30 January 2018, 29 scientists from nine European Countries established the EUROBUS (Towards a EURopean OBservatory of the non-indigenous calanoid copepod
Pseudodiaptomus marinUS
) Working Group (WG). This WG aimed at creating a European network of institutions and researchers working on the various aspects of the biology and ecology of
P
.
marinus
, with an open forum where sharing experience and know-how among WG participants. This brought to an updated distribution map of
P
.
marinus
in European waters, as well as to the identification of priority research lines and potential joint initiatives under the WGEUROBUS umbrella. This contribution, stemming from the experts participating at the WG, represents the manifesto of the current and future initiatives developed within WGEUROBUS.
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The morphology and composition of aerosol particles in the ground-level Moscow atmosphere have been studied by scanning electron microscopy and X-ray spectral microanalysis. The results are ...interpreted considering seasonal, synoptic, and meteorological conditions. The main morphological types of particles of natural and anthropogenic origin are revealed.
The seasonal changes in the elemental composition of surface aerosol in Moscow are considered in four data series: for summer and autumn 2019 and winter and spring 2020. The surface aerosol is ...significantly enriched with sulfur, heavy metals, and metalloids (Cu, Zn, Cd, Sb, Pb, Bi, etc.). The mass concentrations, mass percentages, and enrichment factors for different elements in aerosol particles are determined and compared for different seasons. The spatial distribution of elements in surface aerosol is not uniform through the city, which may be associated with the specificity of local sources, underlying surface, and wind regime in different regions of Moscow. The highest concentrations of a number of terrigenous and anthropogenic elements are revealed in the Central Administrative District of Moscow. The causes for seasonal variability in the elemental composition of surface aerosol in the Moscow megalopolis and possible sources of elements are discussed.
Partial oxidation of methane into syngas at short contact times (5–15
ms) was studied in both steady-state and transient modes at temperatures up to 850
°C in realistic feeds (CH
4 content up to 20%, ...CH
4/O
2
=
2) with a minimum impact of mass and heat transfer for structured catalysts carrying Pt/Ln
0.3Ce
0.35Zr
0.35O
2−
y
(Ln
=
La, Pr, Gd) as thin layers on walls of corundum channel substrates. Oxygen mobility and reactivity of the active phase were characterized by oxygen isotope heteroexchange, temperature-programmed O
2 desorption and CH
4 reduction, isothermal pulse reduction by methane with wide variation of CH
4 concentrations and TAP pulse studies. Experimental data point towards a selective oxidation of methane into syngas via a direct route with oxygen-assisted methane activation. This mechanistic feature is related to the strong Pt-support interaction stabilizing highly dispersed oxidic Pt species less active in CH
4 and syngas combustion than metallic Pt clusters. Support activates O
2 molecules and supplies active oxygen species to Pt sites. A high rate of oxygen diffusion on the surface and in the bulk of the support and Pt-support oxygen spillover stabilizes Pt in a well dispersed partially oxidized state while preventing coking at high concentrations of CH
4 in the feed.
A catalytic composite material containing highly conductive Super P carbon black and platinum nanoparticles has been prepared by the liquid-phase synthesis method and studied. An increase in ...electroactivity of Pt nanoparticles in the presence of highly conductive carbon black has been revealed in comparison with the reference sample, platinized carbon black E-teK, where the carbon material was Vulcan XC-72 carbon black. The nature of the carbon material has been shown to affect the catalytic activity of platinum nanoparticles. The value of the electrochemically active surface area of the developed catalytic material and the catalytic material based on the Etek catalyst has been determined by cyclic voltammetry to be 54 and 20 m
2
/g, respectively.
Human papillomavirus (HPV) is linked with a subset of head and neck squamous cell carcinomas (HNSCC). HPV-positive HNSCCs show a better prognosis than HPV-negative HNSCCs, which may be explained by ...sensitivity of the HPV-positive HNSCCs to ionizing radiation (IR). Although the molecular mechanism behind sensitivity to IR in HPV-positive HNSCCs is unresolved, DNA damage response (DDR) might be a significant determinant of IR sensitivity. An important player in the DDR, SMG-1 (suppressor with morphogenetic effect on genitalia), is a potential tumor suppressor and may therefore be deregulated in cancer. No studies have yet been conducted linking defects in SMG-1 expression with cancer. We investigated whether deregulation of SMG-1 could be responsible for defects in the DDR in oropharyngeal HNSCC.
Expression and promoter methylation status of SMG-1 were investigated in HNSCCs. To identify a functional link between HPV infection and SMG-1, we transfected the HPV-negative cells with an E6/E7 expression construct. SMG-1 short hairpin RNAs were expressed in HPV-negative cells to estimate survival upon IR.
Forced E6/E7 expression in HPV-negative cells resulted in SMG-1 promoter hypermethylation and decreased SMG-1 expression. Due to promoter hypermethylation, HPV-positive HNSCC cells and tumors express SMG-1 at lower levels than HPV-negative SCCs. Depletion of SMG-1 in HPV-negative HNSCC cells resulted in increased radiation sensitivity, whereas SMG-1 overexpression protected HPV-positive tumor cells from irradiation.
Levels of SMG-1 expression negatively correlated with HPV status in cancer cell lines and tumors. Diminished SMG-1 expression may contribute to the enhanced response to therapy exhibited by HPV-positive HNSCCs.
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