The study of organogel formation with cyclo(leucyl-leucine) by the AFM method

This work was supported by the ministry of education and science of russian federation [grant №14.y26.31.0019

Surface morphology and electrocatalytic properties of nickel nanoparticles formed in track pores

© 2016, Pleiades Publishing, Ltd.Structures, each of which is composed of a conducting substrate with a protective dielectric layer containing an array of equal-sized pores formed under the action of high-energy ions and chemical etching, are created. The created pores are electrochemically filled with nickel nanoparticles. With atomic-force microscopy (AFM), it is established that Ni nanoparticles are generated exclusively within ion tracks without film formation on the surface of a silicon-dioxide layer. Histograms illustrating the nanoparticle-diameter distribution are constructed, and areas of the nickel nanoparticles are calculated. The electrochemical and electrocatalytic properties of Ni nanoparticles inherent to ethanol-oxidation reactions are investigated. The catalytic activity per unit area of the nanocatalyst is estimated using voltammograms, AFM data, and histograms characterizing the particle size distribution

Solution structure and equilibrium of new calix[4]resorcinarene complexes - Prototype of molecular machines. NMR data

Association properties and molecular machine application of water soluble calix[4]resorcinarene (1) with two aromatic guests (2-naphthol (2) and 1,5-naphthalenediamine (3)) have been investigated by various NMR methods (chemical shift, nOe and diffusion measurements) in aqueous solution at different concentrations and pH range. In neutral solution 1 strongly associates with 2, while only moderately associating with 3. Increase in concentration causes an increase in the stability of 1 + 3 and 1 + 2 + 3 complexes and produces high order complexes. The decrease of pH does not have an influence on 1 + 2 association, but disrupts 1 + 3 assembly. 1 can be used for the separation of 2 + 3 mixture in aqueous solution at moderate concentrations. The pH dependency of the association properties of the 1 + 3 system makes these compounds prime candidates for pH-responsive molecular machines applications. © Springer Science+Business Media B.V. 2007

Comparative analysis of methanogenic communities in different laboratory-scale anaerobic digesters

© 2016 Ayrat M. Ziganshin et al.Comparative analysis of methanogenic archaea compositions and dynamics in 11 laboratory-scale continuous stirred tank reactors fed with different agricultural materials (chicken manure, cattle manure, maize straw, maize silage, distillers grains, and Jatropha press cake) was carried out by analysis of the methyl coenzyme-M reductase -subunit (mcrA) gene. Various taxa within Methanomicrobiales, Methanobacteriaceae, Methanosarcinaceae, Methanosaetaceae, and Methanomassiliicoccales were detected in the biogas reactors but in different proportions depending on the substrate type utilized as well as various process parameters. Improved coverage and higher taxonomic resolution of methanogens were obtained compared to a previous 16S rRNA gene based study of the same reactors. Some members of the genus Methanoculleus positively correlated with the relative methane content, whereas opposite correlations were found for Methanobacterium. Specific biogas production was found to be significantly correlating with Methanosarcinaceae. Statistical analysis also disclosed that some members of the genus Methanoculleus positively correlated with the ammonia level, whereas the prevalence of Methanocorpusculum, Methanobacterium, and Methanosaeta was negatively correlated with this parameter. These results suggest that the application of methanogenic archaea adapted to specific feedstock might enhance the anaerobic digestion of such waste materials in full-scale biogas reactors

Atomic-force microscopy of nickel nanoparticles possessing electrocatalytic properties

Surface morphology of highly oriented pyrolytic graphite with electrodeposited nickel nanoparticles was studied by atomic-force microscopy in the presence and absence of ethanol. Voltammetric and atomic-force microscopic data and histograms of particle size distribution were used to evaluate the unit-area catalytic activity of the nanocatalyst in relation to conditions of its preparation. © 2010 Pleiades Publishing, Ltd

Synthesis and study of inorganic pigment properties on the basis of dead chrome catalyst

Generation of unprocessed wastes of industrial production is the key part of multi-factor negative impact on environment. The technologies of catching and neutralization of discharges and wastes have been developed extremely slow, as a result of it, the level of utilization remains to be low (only half of them is reused in production). All these concern in full measure chemical industry and adjacent branches of production - coal industry, mining, metallurgy, energy. In particular, only in chemical industry it has been calculated about 800 names of wastes. Major part of wastes is deleterious and hazardous to biosphere, processing toxicity, chemical, biological activities, corrosiveness, inflammability and explosibility. On the other hand - industrial wastes contain valuable elements, in particular different metals, the reserves of them are exhaustible. Waste burial is unpractical from the point of view of stability of functioning of industrial complex on the whole. The industrial wastes are often multi-component mixtures of substances of heterogeneous chemical composition, having different physical and chemical properties. The processes of interaction between the components and the background objects and by-product assimilation bring a considerable uncertainty in chemical composition and material constitution of industrial wastes. The technologies of waste recycling to receive the products, specifically inorganic pigments, involve the complex of methods of processing with the use of different modifiers to obtain the needed complex of physical and chemical properties defining the functional characteristics of the target product

Atomic force microscopy of cobalt nanoparticles with electro-catalytic properties

A method of controlled potential electrodeposition of the cobalt nanoparticles with sizes from 30 to 400 nm on the surface of highly oriented pyrolytic graphite has been developed. The images of nanoparticles were obtained with an atomic force microscope. A computer program was applied to obtain the size distribution of electrodeposited particles depending on the electrodeposition potential, electrolytic concentration, and deposition time. Using voltammetry it has been established that the cobalt nanoparticles with the diameter of about 50 nm show the maximal catalytic activity during electro-oxidation of ethanol. © Pleiades Publishing, Ltd., 2009

Non-zeolitic properties of the dipeptide l-leucyl-l-leucine as a result of the specific nanostructure formation

© the Owner Societies 2017. The non-zeolitic behavior of l-leucyl-l-leucine and its self-organization in solid state and from solutions with the formation of different nanostructures are reported. This dipeptide forms porous crystals, but does not exhibit molecular sieve effects typical of classical zeolites and biozeolites. The specific sorption properties of l-leucyl-l-leucine result from a change in its crystal packing from channel-type to layered-type, when binding strong proton acceptors or proton donors of molecular size greater than 18-20 cm 3 mol -1 . The high sorption capacity of l-leucyl-l-leucine toward dichloromethane results from the self-organization of the dipeptide, by forming nanofibers or web-like structures. The low thermal stability of clathrates of the dipeptide containing large guest molecules and the selectivity of l-leucyl-l-leucine toward alcohols over nitriles can be used to separate organic mixtures such as methanol/n-butanol and methanol/acetonitrile

The effect of substrate and air humidity on morphology of films of L-leucyl-L-leucine dipeptide

The effect of a substrate and air humidity on the morphology of a thin film of L-leucyl-L-leucine dipeptide was studied. For this purpose, conditions for obtaining a thin film of the dipeptide were determined by thermal analysis. The morphology of L-leucyl-L-leucine film deposited on the surface of highly oriented pyrolytic graphite (HOPG) and mica at different humidities was studied by atomic force microscopy. It was established that film was formed on the surface of HOPG and uniformly coated with nanostructures, the sizes and shapes of which depended on the film thickness. Crystallization of the dipeptide with the formation of complex crystalline nanosized objects occurs on the surface of mica. An increase in air humidity results in a decrease in the geometric dimensions of nanostructures on the surface of the dipeptide film in the case of HOPG and complication of crystal agglomerate structure when mica was used as a substrate. © 2014 Pleiades Publishing, Ltd