Nanotechnologies in Russia最新文献

Modern methods of metagenomics, including those based on long reads of nanopore sequencing, are especially relevant for environmental-monitoring tasks, in particular, for assessing the anthropogenic impact on natural communities of microorganisms. These include algal-bacterial communities that live in water-treatment plants and participate in the biological treatment of wastewater from excess organic waste and nutrients (phosphorus and nitrogen). Metagenomic analysis shows changes in the taxonomic composition and functional profile of the algal-bacterial community when simulating the release of drugs into wastewater: broad-spectrum antibiotics (for example, ceftriaxone) and nonsteroidal anti-inflammatory drugs (for example, diclofenac). The results of metagenomic analysis based on long reads of nanopore sequencing and classical methods of environmental monitoring, including metabarcoding based on short reads on a second-generation sequencing platform, are compared. Nanopore sequencing of the entire metagenome shows a greater biodiversity of samples compared to the DNA metabarcoding of short reads, makes it possible to determine the taxonomic affiliation of particular organisms more accurately, identify groups of eukaryotic oxygenic phototrophs, and also reveal the presence of antibiotic-resistance genes in the community. It is shown that under the influence of medicinal substances, the algal-bacterial community is enriched with antibiotic-resistant bacteria. At the same time, despite maintaining the rate of phosphorus removal, the community’s potential for the removal of nutrients is reduced, which is expressed in a two-order reduction in the relative representation of inorganic-nutrient metabolism genes. Simultaneous exposure to ceftriaxone and excess nutrients in the wastewater leads to the maximum enrichment of antibiotic-resistant organisms, as well as the replacement of cyanobacteria originally present in the community with eukaryotic microalga.

Currently, silver nanoparticles (AgNPs) are increasingly used as biocides, but when released into the environment, they can affect nontarget organisms. In this regard, there is an increasing need to develop the synthesis of AgNPs using biological agents. However, the toxic effect of biogenic AgNPs on aquatic organisms has not been studied in detail. A model is proposed for using the freshwater ciliate Paramecium caudatum as a test organism to assess the toxic effect of AgNPs synthesized using sphagnum moss. The effect of different concentrations of biogenic AgNPs is studied based on the biological responses of paramecia on survival, growth rate, chemotaxis, phagocytosis, and macronucleus morphology. The results show that AgNPs stabilized with sphagnum extract is toxic to ciliates, demonstrating a pronounced dose-dependent effect.

Actinidia Lindl. is a genus of plants, some species of which are of great economic importance. Varieties of large-fruited Actinidia, known as kiwi (A. deliciosa and A. chinensis), are widely distributed on the world market, however, recently attempts have been made to domesticate small-fruited Actinidia, which in Russia are represented by several far-eastern species. The genomics and genetics of Actinidia are developing in different directions, often in accordance with the needs of breeders. The review describes genomic and genetic studies related to the most important agricultural traits of Actinidia: genetic diversity, chemical composition of fruits, sex coding, response to frost, storage, and transportation of crops.

The results of studying 55 Saccharomyces cerevisiae yeast strains, intended for the production of dry white wines from the Crimean autochthonous Kokur White variety, are presented. The study involved 49 strains isolated from spontaneously fermented grape must of various grape varieties grown on the Crimean Peninsula, and six strains of yeast obtained from the All-Russian Collection of Industrial Microorganisms of the National Research Center “Kurchatov Institute” and the Magarach Collection of Winemaking Microorganisms of the Magarach All-Russian National Research Institute of Viticulture and Winemaking, Russian Academy of Sciences. As a result, two yeast strains are selected: Su-48 and Y-693. These are the most promising for the production of wines from the Kokur White variety. These strains contributed to the production of oxidation-resistant wines, as well as the preservation of acidity and the development of intense, bright varietal aromas.

Biogenic silver nanoparticles (AgNPs) obtained using metal-reducing bacteria Shewanella oneidensis MR-1 and silver-nitrate salts are included in liquid and dry formulations in the composition of such polymeric materials as acrylic paint, epoxy glue, and chelate compounds of copper and zinc with different types of ligands. The preservation of a high level of biocidal activity of AgNPs in the composition of nanocomposite materials in relation to microorganisms of various systematic groups is shown. It is established that the contribution of biogenic AgNPs to the activity level of biocidal metal chelates is 20–25%. For the first time, an assessment of the antimicrobial properties of the original polymer materials is carried out and the different sensitivity of strains to their effects is revealed, which indicates the need to take into account strain specificity when selecting components of a biocidal nanocomposite material.

Photonic crystals obtained by the modified Stöber method with the natural sedimentation of nanospheres is investigated. The surfaces of the silica nanospheres are investigated using atomic-force microscopy. The surfaces of all samples have a cauliflower structure. The structure of the photonic crystals is studied by the method of small-angle synchrotron radiation scattering (SASRS). The SASRS curves exhibit two or three regions with different scattering intensities. Three original techniques for analyzing the data obtained are proposed. Periodicity in the dependence of the logarithm of intensity on the scattering vector at the smallest wavenumbers, related to scattering from nanospheres, is found. The influence of the water/TEOS molar ratio on the size and concentration of these particles is revealed. Particles of two types (nanospheres and subglobules) are observed at low water concentrations (6–8 mol/L), whereas at water concentrations of 13–23 mol/L the particles are of three types (nanospheres, subglobules, and grains). The morphology of the detected particles is estimated.

In this work, a thermoelectric material with the nominal composition Zn_0.97Al_0.02Ni_0.01O is synthesized using the chemical coprecipitation method. The synthesized powder consists of the main phase of wurtzite with a small content of Ni_1–zZn_zO; the change in the crystal-lattice parameters of the main phase indicates the replacement of Zn²⁺ with Al³⁺. The Ni_1–zZn_zO phase is predominantly located at the grain boundaries, blocking their growth during spark-plasma sintering. The resulting morphology enhances phonon scattering processes, which leads to a decrease in thermal conductivity. The electrical conductivity exhibits activation behavior and increases significantly in comparison with undoped ZnO, because the concentration of charge carriers increases with the substitution of Zn²⁺/Al³⁺. Thus, the chemical coprecipitation method allows one to obtain doped ZnO with an increase in thermoelectric performance of more than 2 times relative to undoped ZnO.