The theory of the plasmon resonance excitation in the plasmonic-crystal structure on a dielectric substrate is presented. The effect of the plasmon resonance intensity oscillation as a function of ...the substrate thickness is predicted. It is shown that the enhancement of the plasmon resonance intensity occurs in a broad terahertz frequency range in the structure on a membrane substrate.
•Information about PU and PU based flame retardants, chemistry, structure and properties.•To help readers to understand about the PU based flame retardant.•Explaining many of the research work on PU ...based different flame retardant.
The present review summarizes the research work of flame retardant coatings on polyurethane flexible foam in particular, this review highlights the different type of flame retardant and their preparation, characterisation methods.
Organizational aspects of specialized including high-tech oncological medical care in a multi-field hospital are shown. A 10-year experience of the Pirogov National Medical and Surgical Center ...regarding optimization of the treatment of cancer patients is reported. Effectiveness of oncological care organization in a multi-field hospital is preliminary concluded. It is emphasized that multidisciplinary approach is essential for selecting a personalized program of cancer treatment in these patients. The need for further searching for ways to improve the diagnosis and treatment of cancer patients by accumulating and analyzing large clinical material is marked.
Highly saturated lithium-graphite intercalation compounds (of a composition LiC2LiC4) synthesized under high-pressure conditions were investigated using X-ray diffraction. It was shown that these ...compounds present the structure with hexagonal unit cell with a parameter 8.63 Å, c = 3Ic = 3 · 3.7 = 11.1 Å. The most probable stoichiometry for this unit cell is LiC2.67, as deduced from the comparison of the calculated and observed intensities of (hkℓ) reflections. It is supposed that this structure is the most “stable” step in decomposition of LiC2 compound obtained under pressure.
About 10 μs after the Big Bang, the universe was filled—in addition to photons and leptons—with strong-interaction matter consisting of quarks and gluons, which transitioned to hadrons at ...temperatures close to kT = 150 MeV and densities several times higher than those found in nuclei. This quantum chromodynamics (QCD) matter can be created in the laboratory as a transient state by colliding heavy ions at relativistic energies. The different phases in which QCD matter may exist depend for example on temperature, pressure or baryochemical potential, and can be probed by studying the emission of electromagnetic radiation. Electron–positron pairs emerge from the decay of virtual photons, which immediately decouple from the strong interaction, and thus provide information about the properties of QCD matter at various stages. Here, we report the observation of virtual photon emission from baryon-rich QCD matter. The spectral distribution of the electron–positron pairs is nearly exponential, providing evidence for a source of temperature in excess of 70 MeV with constituents whose properties have been modified, thus reflecting peculiarities of strong-interaction QCD matter. Its bulk properties are similar to the dense matter formed in the final state of a neutron star merger, as apparent from recent multimessenger observation.
Development of efficient approaches for the production of medically important nucleosides is a highly relevant challenge for biotechnology. In particular, cascade synthesis of arabinosides would ...allow relatively easy production of various cytostatic and antiviral drugs. However, the biocatalyst necessary for this approach, ribokinase from Escherichia coli (EcoRK), has a very low activity towards D-arabinose, making the synthesis using the state-of-art native enzyme technologically unfeasible. Here, we report the results of our enzyme design project, dedicated to engineering a mutant form of EcoRK with elevated activity towards arabinose. Analysis of the active site structure has allowed us to hypothesize the reasons behind the low EcoRK activity towards arabinose and select feasible mutations. Enzyme assay and kinetic studies have shown that the A98G mutation has caused a large 15-fold increase in kcat and 1.5-fold decrease in KM for arabinose phosphorylation. As a proof of concept, we have performed the cascade synthesis of 2-chloroadenine arabinoside utilizing the A98G mutant with 10-fold lower amount of enzyme compared to the wild type without any loss of synthesis efficiency. Our results are valuable both for the development of new technologies of synthesis of modified nucleosides and providing insight into the structural reasons behind EcoRK substrate specificity.
The results of gravimetric and electrochemical polarization investigations demonstrate that the isopropanol extract of rapeseed oil cake can be used as an efficient volatile inhibitor of the ...atmospheric corrosion of copper. The efficiency of action of the surface film in the course of its formation depends on the composition of the gas-vapor phase and, under the conditions of wetting of the metal surface, the corrosion rate is determined by the rate of the cathodic process of reduction of the atmospheric oxygen. In estimating the adsorption activity of organic molecules according to the indices of reactivity and in studying the morphology of specimen surface, we assume that the efficiency of action of the isopropanol extract in the initial stage is caused by the chemisorption of volatile organic components of the rapeseed oil cake, which then interact with each other and transform into surface phase films containing copper ions, water, and organic substances.
Two forms were found in the NMR spectra of N6-substituted 2-chloroadenosines. The proportion of the mini-form was 11–32% of the main form. It was characterized by a separate set of signals in COSY, ...15N-HMBC and other NMR spectra. We assumed that the mini-form arises due to the formation of an intramolecular hydrogen bond between the N7 atom of purine and the N6–CH proton of the substituent. The 1H,15N-HMBC spectrum confirmed the presence of a hydrogen bond in the mini-form of the nucleoside and its absence in the main form. Compounds incapable of forming such a hydrogen bond were synthesized. In these compounds, either the N7 atom of the purine or the N6–CH proton of the substituent was absent. The mini-form was not found in the NMR spectra of these nucleosides, confirming the importance of the intramolecular hydrogen bond in its formation.
The review is devoted to current and promising areas of application of graphene and materials based on it for generating environmentally friendly hydrogen energy. Analysis of the results of ...theoretical and experimental studies of hydrogen accumulation in graphene materials confirms the possibility of creating on their basis systems for reversible hydrogen storage, which combine high capacity, stability, and the possibility of rapid hydrogen evolution under conditions acceptable for practical use. Recent advances in the development of chemically and heat-resistant graphene-based membrane materials make it possible to create new gas separation membranes that provide high permeability and selectivity and are promising for hydrogen purification in processes of its production from natural gas. The characteristics of polymer membranes that are currently used in industry for the most part can be significantly improved with small additions of graphene materials. The use of graphene-like materials as a support of nanoparticles or as functional additives in the composition of the electrocatalytic layer in polymer electrolyte membrane fuel cells makes it possible to improve their characteristics and to increase the activity and stability of the electrocatalyst in the reaction of oxygen evolution.
The new JINR project 1 is aimed at studies of highly excited nuclear matter created in nuclei by a high-energy deuteron beam. The matter is studied through observation of its particular decay ...products - pairs of energetic particles with a wide opening angle, close to 180°. The new precision hybrid magnetic spectrometer SCAN-3 is to be built for detecting charged (π±, K±, p) and neutral (n) particles produced at the JINR Nuclotron internal target in dA collisions. One of the main and complex tasks is a study of low-energy ηA interaction and a search for η-bound states (η-mesic nuclei). Basic elements of the spectrometer and its characteristics are discussed in the article.
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