The Russian Bioimpedance Database: An Update.

Extensive bioelectrical impedance analysis (BIA) data have the potential of health monitoring and the assessment of health risks at the population level. The importance of BIA data lies in their availability and abundance for many countries. In Russia, mass BIA data are generated by the national network of health centers (HCs). Our aim was to describe the structure and capabilities of the updated HCs' BIA database. Upon several requests between 2012 and 2020, 369 HCs representing all Federal districts of Russia and 60 out of 85 Federal subjects in them, submitted raw bioimpedance data which were obtained using the same type of BIA instrument, namely ABC-01 'Medas' (SRC Medas, Russia). After application of strict selection criteria, 2,429,977 BIA measurement records were selected that formed the updated 2010-2019 HCs' database. Various slices of the BIA data are described according to spatiotemporal, demographic and other characteristics. Reference curves of the bioimpedance phase angle according to age and sex are presented. Limitations and prospects for further work are outlined. We believe that, after appropriate sampling, the database can be utilized to study biological, geographical, social and other associations of the bioimpedance and body composition parameters, for generating updated national references, international comparisons and data standardization.

Chitosan/hyaluronic acid polyanion bilayer applied from carbon acid as an advanced coating with intelligent antimicrobial properties for improved biological prosthetic heart valves.

The tightly bonded shielding coating on biomatrix significantly enhances the functionality of medical devices, bioprostheses in particular. In our work we have obtained a polyelectrolyte coating on a biomatrix by sequentially depositing chitosan and hyaluronic acid (HA) from solutions in carbonic acid under pressure. This approach makes it possible to obtain hybrid biomatrix with a firmly bonded polymer screen due to the electrostatic bonding of polyions. High-precision analysis using a tritium label shows a 3-fold increase in quantity of HA in carbonic acid under pressure compared to the conventional method. The presence of the chitosan layer increases the HA adsorption by 15-20 % due to electrostatic interaction of differently charged polymers. Antimicrobial results show the possibility of implementing an induced antimicrobial response, due to the lysis of the upper layer of the coating (HA) and the release of antimicrobial agents in the case of growth of pathogens on the bioprosthesis.