Cationic Oligomerization of the Pyrolysis C<Subscript>5</Subscript> Fraction

The cationic oligomerization of the pyrolysis C₅ fraction in the presence of catalyst systems based on AlCl₃, VOCl₃, BF₃ · O(C₂H₅)₂, and a Gustavson complex has been investigated. It has been shown that the use of the diisopropyl ether-modified Gustavson complex in the reaction makes it possible to synthesize fully soluble oligomers in high yields. The conversions of all the unsaturated components of the pyrolysis fraction to the oligomer at different durations of the oligomerization process have been determined. The synthesized oligomers are characterized by high unsaturation and exhibit the properties of film-forming compounds.     

West Siberian palsa peatlands: distribution,typology, cyclic development,present day climate-driven changes,seasonal hydrology and impact on CO2 cycle

Palsa peatlands occupy extensive areas in Western Siberia which is one of the most paludified flat lowlands of the world. Climatic changes in Western Siberia are more dramatic compared with other northern regions, and changes in palsa landscapes are more notable due to the severe continental climate here. The distribution, peculiarities and climate-indication capacities of West Siberian palsas are poorly known outside Russia. Thus, Western Siberia is one of the most interesting vast natural polygons for studying climate-driven changes in the landscapes. This paper aims to fill the gap in knowledge on West Siberian palsas and their capacity as a climate regulator. We present issues in distribution, typology and cyclic development of palsa peatlands and their actual climate-driven changes. We also analyse the role of palsas in the atmospheric cycle of CO₂, and the hydrology of the palsa regions.     

Peculiarities of Granulation of the PAP-2 Aluminum Powder in the Technology of the Al–Al2O3 Powder Composite with a Layered Structure

Russian Journal of Non-Ferrous Metals - An analysis of modern scientific-and-technical information evidences great prospects for using composite materials (CMs) based on the Al–Al2O3 system....     

The Role of Natural Polymorphic Variants of DNA Polymerase β in DNA Repair

DNA polymerase β (Polβ) is considered the main repair DNA polymerase involved in the base excision repair (BER) pathway, which plays an important part in the repair of damaged DNA bases usually resulting from alkylation or oxidation. In general, BER involves consecutive actions of DNA glycosylases, AP endonucleases, DNA polymerases, and DNA ligases. It is known that protein–protein interactions of Polβ with enzymes from the BER pathway increase the efficiency of damaged base repair in DNA. However natural single-nucleotide polymorphisms can lead to a substitution of functionally significant amino acid residues and therefore affect the catalytic activity of the enzyme and the accuracy of Polβ action. Up-to-date databases contain information about more than 8000 SNPs in the gene of Polβ. This review summarizes data on the in silico prediction of the effects of Polβ SNPs on DNA repair efficacy; available data on cancers associated with SNPs of Polβ; and experimentally tested variants of Polβ. Analysis of the literature indicates that amino acid substitutions could be important for the maintenance of the native structure of Polβ and contacts with DNA; others affect the catalytic activity of the enzyme or play a part in the precise and correct attachment of the required nucleotide triphosphate. Moreover, the amino acid substitutions in Polβ can disturb interactions with enzymes involved in BER, while the enzymatic activity of the polymorphic variant may not differ significantly from that of the wild-type enzyme. Therefore, investigation regarding the effect of Polβ natural variants occurring in the human population on enzymatic activity and protein–protein interactions is an urgent scientific task.     

Pulsed laser reshaping and fragmentation of upconversion nanoparticles — from hexagonal prisms to 1D nanorods through “Medusa”-like structures

One dimensional (1D) nanostructures attract considerable attention, enabling a broad application owing to their unique properties. However, the precise mechanism of 1D morphology attainment remains a matter of debate. In this study, ultrafast picosecond (ps) laser-induced treatment on upconversion nanoparticles (UCNPs) is offered as a tool for 1D-nanostructures formation. Fragmentation, reshaping through recrystallization process and bioadaptation of initially hydrophobic (β-Na_1.5Y_1.5F₆: Yb³⁺, Tm³⁺/β-Na_1.5Y_1.5F₆) core/shell nanoparticles by means of one-step laser treatment in water are demonstrated. “True” 1D nanostructures through “Medusa”-like structures can be obtained, maintaining anti-Stokes luminescence functionalities. A matter of the one-dimensional UCNPs based on direction of energy migration processes is debated. The proposed laser treatment approach is suitable for fast UCNP surface modification and nano-to-nano transformation, that open unique opportunities to expand UCNP applications in industry and biomedicine.

     

The capability to reduce primary energy demand in EU housing

The European Union has been demonstrating its adherence to energy efficiency policy in the last decade. At the main EU summits there were stated the requirements to reduce energy consumption in the EU, and to make it sustainable over the long term. The “20-20-20” promise of a 20% share of renewable energies in total EU energy consumption and a 20% reduction of greenhouse gas emissions in the EU by 2020 was determined in 2007 and affirmed in 2008. The paper deals with the evaluation of some ways of reaching a 20% reduction in primary energy demand in housing. For that purpose some measures leading to such a reduction for a dwelling house are estimated. These measures require an additional investment into the energy performance of a building. For the achievement of goals stated by the European Parliament in energy demand it will be necessary to involve a considerable level of financial and technical support in these spheres. An estimation of the amount of supporting program funds is also presented in the paper.     

Processing low-grade oxidized coal to produce effective carbon sorbents

High-porosity sorbents may be produced by carbonization of low-grade oxidized coal in the presence of alkali.     

Densification of transparent yttrium aluminum garnet (YAG) by SPS processing

Nano-size YAG powder co-mixed with 0.25 wt.% LiF was used to fabricate transparent polycrystalline YAG specimens by means of the Spark Plasma Sintering (SPS) technique. The presence of the LiF additive in the initial nano-powder allows obtaining fully dense disc shaped (up to 4 mm thick) transparent specimens at the outcome of a 2 h treatment at 1300 °C. The presence of LiF plays a key role in the mass transport related effects during the densification of YAG to full density and also in the elimination of the residual carbon contamination, allowing reaching a level of optical transmittance close to the theoretical value.     

Environmentally Benign Oxidation of Alkylphenols to p-Benzoquinones: A Comparative Study of Various Ti-Containing Catalysts

Catalytic properties of Ti-containing porous solids were compared in the oxidation of 2,3,6-trimethylphenol (TMP) with H₂O₂ to produce 2,3,5-trimethyl-1,4-benzoquinone (TMBQ, vitamin E key intermediate). Mesoporous titanium–silicates with di(oligo)nuclear Ti centers, metal–organic framework MIL-125 and amorphous TiO₂ demonstrated 100 % selectivity toward TMBQ. Titanium–silicates prepared by evaporation-induced self-assembly revealed superior performance in terms of product yield and catalyst reusability.