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The widespread occurrence of coronavirus disease 2019 (COVID-19) in the world has led to a sharp de-crease in the number of cardiac surgery interventions and had a negative impact on treatment outcomes. We present an overview of the available literature on the effects of COVID-19 on cardiac surgery at this time. The lack of randomized studies and guidelines on the tactics of perioperative management of patients with cardiovascular pathology encourages to rely on isolated clinical cases presented in the literature. The presence of cardiovascular disease in COVID-19 patients has been identified as a risk factor associated with high morbidity and mortality from the first days of the pandemic. In addition to older age, chronic comorbidities increase the risk of severe COVID-19 infection as well as its lethal outcome. Among the predictors of 30-day mortality in COVID-19 patients in the postoperative period the following were under-lined: male sex (p˂0.001), high risk class according to the American Society of Anesthesiologists (ASA) (p˂0.001), age over 70 years (p˂0.001), emergency surgery (p = 0.026), oncological surgery (p = 0.046). To date, there are no studies on the perioperative management of cardiac surgery patients with acquired heart disease with persistent post-COVID-19 lung disease. We present the results of our own experience of perioperative management of a cardiac surgery patient with COVID-associated outpatient bilateral polysegmental pneumonia. Patients with cardiac surgery after COVID-19 required intensive preoperative preparation. Appointment of the proposed scheme of antibacterial therapy in combination with corticosteroids has reduced the intensity of inflammatory changes in lung tissue. Surgical improvement of intracardiac hemodynamics under cardiopulmonary bypass led to complete reduction of lung parenchyma injury and restoration of the respiratory system. Results. In patients with acquired heart disease, respiratory failure can be caused not only by post-COVID-19 lung injury, but also by impaired intracardiac hemodynamics with increased pulmonary artery pressure due to the initial heart disorders. Restoration of adequate gas exchange function in the group of post-COVID-19 patients is ineffective without timely cardiac surgery.

Purpose: Technical capabilities of the MARK-4B antenna system necessary for its further using as a 32-meter radiotelescope (RT-32) and making simultaneous spectral radioastronomical observations in the C and K frequency ranges, are investigated. Design/methodology/approach:The studies use the results of our own measurements made with the МАRK-4В antenna system, expert reviews, open information sources, technical documentation of the MARK-4B antenna system, radio astronomy and computer simulation methods and comparative analysis of this antenna main parameters with the corresponding parameters of the world’s best active radio telescopes. Combining different approaches allows us to determine the requirements for the receiving system, parameters of the spectrometer, calibration techniques and optimize the МАRK-4В antenna system modernization procedure. Findings: The radio telescope main parameters required for spectral observations in the C and K frequency ranges are determined. The antenna pointing system capabilities are specified. For the MARK-4B antenna system working frequency range, the main spectral lines of various molecules available for research have been considered. The transitions radiating the most intensive spectral lines are listed. The radio astronomical problems that can be solved using the MARK-4B in the mode of spectral observations are formulated. The required parameters of the spectrum analyzer and the receiver’s self-noise temperature are determined. Calibration techniques of the recorded signal are described, which are necessary for carrying out spectral observations. Conclusions: The here presented studies show that for making spectral observations based on the beam-waveguide MARK-4B antenna system, it is technically possible to create the RT-32 radio telescope with quality technical characteristics corresponding to the world-best analogs. Modernization of the beamwaveguide MARK-4B antenna system will allow at the first stage to create in Ukraine the dual-band radio-telescope permitting to make simultaneous spectral and/or continued observations in the C and K ranges. Henceforth, the amount of simultaneously working ranges can be increased.

Purpose: Creating a radio telescope based on the MARK-4B antenna system being developed for telecommunication applications, determining the possibilities of using the broadband multirange operation of a beam wave-guided antenna system and to evaluate the antenna characteristics using the radioastronomical measurements. Design/methodology/approach: Acomprehensive analysis of all the MARK-4B systems allows to select the blocks and nodes to be replaced or upgraded. The analysis of the reflector and subreflector design, beam wave-guide, corrugated horn, and feeder system allows determining the possible frequency ranges of the radio telescope being created. Installing a broadband receiver with the stipulated calibration capabilities using cooled and uncooled load attenuators allows to determine the antenna system temperature. Guiding the antenna to the calibration sources and recording scans due to the Earth rotation eliminates the systematic errors or errors of the pointing system. In this way the width of the radiation pattern and the effective area of the radio telescope are determined. Findings: An analysis of the antenna design was made and the priority stages of the reconstruction of the MARK-4B antenna system were determined. The narrow-band transmitter and the C-band receiver were dismantled and a wide-band receiver (range 4.6 - 5.1 GHz) with a detector and the possibility of changing the signal integration time were installed. The observed results have allowed to initially estimate the system temperature mea-surements which allow us to hope that the RT-32 radio telescope (Zolotchiv, Lviv region, Ukraine) together with the cooled receiver will have low self noise. A new antenna pointing system has been calculated and installed which using in the C-band has allowed astronomical tests of the radiation pattern width (≈7.2') and the level of its side lobes (–12.5 dB), effective area (≈680 m2) and surface utilization factor (≈0.84). Conclusions: The completed measurements and calculations show that the MARK-4B antenna system allows to createhighly efficient radio astronomy instrument. The developed for now receiving and pointing systems for the RT-32 radio telescope testify to the high potential of Ukrainian science. Further cooperation between scientific research and high technologies will lead to the creation of an effective Ukrainian radio telescope of the centimeter wavelength range.