Microstructured Substrates for Counting Bacteria Formed by Ion Implantation

© 2020, Pleiades Publishing, Ltd. Abstract: A novel technological approach based on ion implantation for obtaining nanostructured substrates for the visual characterization of ultrasmall biological objects and microorganisms has been described. By means of argon-ion implantation of silicate glasses through surface masks made of copper wire mesh, periodic microstructures in the form of gratings with mesh sizes of 50 × 50 μm were formed. The novel substrates were tested by scanning electron microscopy and energy-dispersive X-ray analysis, as well as atomic force microscopy, using bacteria of the genera Bacillus and Staphylococcus deposited onto their surface

Periodization of holocene climatic cycles based on synchronous variations in the magnetic and geochemical parameters of the sediments of lake Bolshoe Yarovoe (Southwestern Siberia)

© 2020, V.S. Sobolev IGM, Siberian Branch of the RAS. Variations in the magnetic and geochemical properties of the sediments of Lake Bolshoe Yarovoe (Altai Territory) were studied. The data were derived from five core columns (up to 4.5 m long) covering a time interval of more than 8000 years. In addition, coercive spectra were obtained for 792 samples taken every 2 cm. Coercive spectra were then used to identify soft magnetic (10-15 mT) and hard magnetic (35-50 mT) components. The soft magnetic component is detrital, and the hard magnetic component is biogenic, which is confirmed by microscopic studies. Moreover, the samples contain micrometeorite particles. Variations in geochemical properties allow reconstruction of the environmental history of the lake. Sediments in the lower part of the section vary both in the content of ferrimagnetic components and in geochemical properties, which indicates a sharp environmental change between ∼6100 and ∼7600 years ago. Quasiperiodic alternation of warm (dry) and cool (humid) periods is observed higher in the section, between ∼4100 and ∼6100 years ago. The variations in the magnetic components are consistent with the environmental changes and can be used for the historical reconstruction

Single-stage plasma-chemical synthesis and characterization of carbon nanoparticle-polymer suspensions

© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim A thin-film styrene polymer–carbon nanoparticle composite was obtained in a single-stage alternating current dielectric barrier discharge plasma-chemical process. The allotropic forms of the carbon nanoparticle filler were traced by transmission electron microscopy (TEM). TEM revealed an extraordinary adhesive encapsulation of the carbon nanoparticles by the polymer. It was found that the corona discharge regime provides an onion-like carbon filler that enhances the mechanical strength and chemical resistance of the synthesized polymer–carbon nanoparticle film. Measurements of the electrical properties of the films implicitly confirmed the uniformity of the carbon filler distribution

Effect of White Phosphorus on the Survival, Cellular Morphology, and Proteome of Aspergillus niger

© 2020, Pleiades Publishing, Inc. Abstract: In the present study, the mechanisms of Aspergillus niger AM1 and AM2 resistance to white phosphorus were studied. It was shown that the presence of white phosphorus (P4) at a concentration of 0.25% in the medium had a marginal impact on the ratio of living to dead cells during fungal cultivation, which indicates a high resistance of the strains to P4. Observations made with electron microscopy showed an increase in the thickness of the fungal cell wall, which is a barrier to the penetration of white phosphorus. MALDI results revealed the biosynthesis of new protein enzymes that could potentially participate in the neutralization of white phosphorus. In addition, white phosphorus caused activation of the metabolism, accompanied by an increase in the number of mitochondria in the cells