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Climate change results in increased attention to factors determining the dynamics of biogeochemical processes in the active layer of biosphere (seasonally thawing/freezing soils) at the boundary with permafrost. There are geological, geomorphic, and weather conditions associated with atmospheric precipitation, which determine the differences in the segregation and the thawing depth of permafrost in various regions. The research area is the Bureya River Basin with discontinuous permafrost within unique landscape units: Mari. They are formed in swampy and poorly drained areas where the active soil layer is in contact with permafrost, and they exert a direct impact on the quality of surface waters. The results of the study include data on the chemical composition of water in tributaries of different orders; spectral characteristics of soluble organic matter (OM) in water extracts (WEs) of soils from different horizons of the active layer; and the assessment of the activity of microbial complexes in relation to humic substances (HSs), depending on the permafrost depth. The heterogeneity of landscapes is an important factor, influencing the transport of OM into watercourses. Microbial complexes of the active layer involved in the transformation of HSs play a decisive role in changing the composition of soluble OM. It is experimentally shown that temperature affects the qualitative composition of metabolism products of HSs, including the ratio of aliphatic and aromatic fragments to chromophoric groups responsible for the color of natural waters. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (rGO) has attracted interest in its potential application in large area photodetectors owing to its ease of manufacture and wideband optical absorbance. Here, we report that thin rGO films produced via vacuum filtration of GO followed by reduction by immersion in L-ascorbic acid are capable of sensing light through a bolometric mechanism. The photoresponse of these rGO thin films can be further enhanced by dropcasting graphene quantum dots (GQDs) on the rGO surface. These GQDs were observed to increase the opacity of the rGO film and hence its absorptivity of light, thereby enabling a significant increase in the photoresponse of the device. [ABSTRACT FROM AUTHOR]

Two types of microcontainers were prepared by using the adsorption of polyamide on the surface of micrometer-sized inorganic porous calcium carbonate microparticles followed by thermal conversion of the polyamide layers into polyimide coatings. The effect of the preparation conditions on the structure and morphology of the microcontainers was studied by transmission electron microscopy and scanning electron microscopy. The smoothest and defect-free coatings were prepared using polyethylenimine as the supporting polymer. The thickness of the polyamide/polyimide shells was estimated by atomic force microscopy and scanning electron microscopy between 50 and 150 nm depending on the quantity of the layers. The water-soluble antibiotic, doxorubicin hydrochloride, was used as a model compound to demonstrate the efficiency of the microcontainers for encapsulation. The resistance of the novel microcontainers to solvent treatment was visualized by the confocal scanning fluorescence microscopy. It was demonstrated that the combination of the high thermal and chemical resistance of polyamide/polyimide shell and the sorption capacity of the CaCO3 is very useful for development of highly protective microcontainers and thermal detectors for smart fabrics.

Serum samples obtained from 33 patients with acute rheumatic fever (ARF), 60 patients with rheumatic heart disease (RHD) and 30 adult healthy persons have been studied. Antibodies to streptococcal A polysaccharide (SAP) and lypoteichoic acid (LTA) were examined by ELISA, to streptolysin O by standard technique. SAP antibodies in high titers persisted from 5 to 12 months in ARF and rheumatic carditis patients especially when RHD was developing. High titers of antibodies to LTA and SLO persisted for 3 months since ARF onset, then fell (p < 0.05). ELISA proved sensitive in determination of antibodies to SAP and LTA. Its combination with determination of the titers to SLO antigens confirmed Streptococcus A infection involvement in emergence of ARF in all the cases including insidious or late-onset carditis and chorea. High levels of antibodies to SAP and LTA were more frequently detected in patients with RHD than in healthy persons (p < 0.001). Correlation between frequency of high levels of antibodies to SAP and bicillin 5 or erythromycin administration, duration of RHD was not established.