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Aim      Dynamic assessment of the right heart in patients with COVID-19-associated pneumonia of different severity during regression of the systemic inflammatory response (SIR).Material an methods    This single-center prospective study included 46 patients with the novel coronavirus infection COVID-19 and viral pneumonia according to chest multispiral computed tomography (CT). Laboratory and echocardiographic examinations of patients were performed.Results Based on the results of evaluation with the Clinical Condition Scale (CCS-COVID), patients were divided into two groups: group A, patients with a score from 6 to 9 and group B, patients with a score from 10 to 14. The study results of both groups were evaluated twice: on day 10±2.5 from the onset of symptoms (groups A10 and B10, respectively) and again on day 17±1.8 (groups A17 and B17, respectively). Patients of group B10 had more pronounced SIR (C-reactive protein, 111.38±52.5 mg / l) and a larger volume of ground-glass opacity (38.3±9.6 %). At the first stage, higher values of right ventricular global longitudinal strain (RV GLS) were detected in group B10 compared to group A10 (23.2±4.8 % vs. 19.9±3.5 %, р=0.048). During the regression of SIR intensity and the positive dynamics of CT, lower values of Е / А were observed in group B17 (1.0 [0.98; 1.2]) vs. group А17 (1.4 [1.18; 1.5, p=0.015), and е' / a' in group B17 (0.66 [0.58; 0.85]) vs. 0.95 [0.79; 1.12] in group B17 (p=0.010). Е / А and е' / a' ratios were correlated with total lactate dehydrogenase fraction (r= -0.452 and p=0.006; r= -0.334 and p=0.050, respectively).Conclusion      In patients with severe COVID-19-associated pneumonia during regression of SIR intensity, changes in the parameters that reflected RV diastolic dysfunction were observed.

A high-sensitivity sensor for measuring moisture content in the air or air humidity under low pressure was designed on the basis of a half-wave coaxial microwave cavity. The method of measuring small variations in the signal phase at a cavity excitation frequency of 1.63 GHz was applied to detect low densities of water vapor. It allows the detection of variations in dielectric air permittivity in the seventh decimal place. A prototype of the sensor was tested in a vacuum chamber. It was calibrated by comparing the test results with the readings of a commercial pressure gauge and using the independent method of measuring the moisture content in rarefied air on the basis of the absorption of millimeter waves in the local line of water vapor at 183 GHz. The developed sensor can be used in laboratory experiments and full-scale geophysical research in the atmosphere onboard various aircrafts.

The article highlights the course of long-term SARS-CoV-2 infection in a patient with a secondary immunodeficiency developed with B-cell-depleting therapy of the underlying disease. Analysis of the intrapatient virus evolution revealed an inpatient S:G75A mutation that alters the 72GTNGTKR78 motif of the S-protein, with a possible role in binding to alternative cellular receptors. Therapy with a ready-made COVID-19-globulin preparation (native human immunoglobulin G (IgG) derived from the plasma of convalescent COVID-19-patients) resulted in rapid improvement of the patient's condition, fast, and stable elimination of the virus, and passive immunization of the patient for at least 30 days. The results suggest the use of products containing neutralizing antibodies opens new prospects for treatment algorithms for patients with persistent coronavirus infection, as well as for passive immunization schemes for patients with a presumably reduced specific response to vaccination.

Objective: To analyze early and delayed results of various variants of circular tracheal resection (CTR) with anastomosis, to determine the safest approach, dates and conditions of correction, features of postoperative period in patients after previous tracheal surgery., Material and Methods: There were 831 patients with cicatricial tracheal stenosis. CTR was made in 330 (39.7%) patients. Most patients had previous prolonged ICU-stay. The patients were divided into 4 groups. Group 1 consisted of 61 (18.5%) patients after previous prolonged tracheal stenting. Group 2 included 45 (13.6%) patients who underwent circular tracheal resection with a functioning tracheostomy. Tracheostomy tube served as a stent in these patients. Group 3 enrolled 32 (9.7%) patients with previous staged reconstructive plastic surgeries on cranial segment of the respiratory tract. Tracheostomy or stent were absent in 192 (58.2%) patients who underwent circular tracheal resection at the first hospitalization. These patients were enrolled into the fourth (control) group. Favorable outcomes (without complications and mortality) were achieved in 85.5% (n=282) of patients. Postoperative complications occurred in 48 (14.5%) patients. Mortality rate was 0.6% (n=2). The greatest number of complications including anastomositis and restenosis was noted in patients after CTR and previous tracheoplasty with T-tube (n=8, 25%). The most common complication in patients after tracheal resection and previous stenting was anastomositis (14.7%). Long-term results depended on postoperative complications and methods of their correction. Recurrent stenosis occurred in 5 (1.5%) patients within the period of 3 months - 8 years. CTR after previous tracheoplasty with T-tube was carried out in 4 of these patients., Conclusion: Tracheal resection after preliminary stenting or tracheostomy is quite safe and technically feasible. Stenting allows postponing radical surgery for correction of concomitant diseases and closure of tracheostomy as a focus of infection within the surgical approach and further tracheal anastomosis. Tracheal resection with simultaneous closure of tracheostomy results a higher rate of postoperative complications compared with preliminary stenting.

New experimental results regarding "warm" water dimer spectra under equilibrium conditions are presented. An almost equidistant series of six peaks corresponding to the merged individual lines of the bound dimer with consecutive rotational quantum numbers is studied in the 188-258 GHz frequency range in water vapour over a broad range of pressures and temperatures relevant to the Earth's atmosphere. The series is a continuation of the sequence detected earlier at lower frequencies at room temperature. The signal-to-noise ratio of the observed spectra allowed investigating their evolution, when water vapour was diluted by atmospheric air with partial pressure from 0 up to 540 Torr. Analysis of the obtained spectra permitted determining the dimerization constant as well as the hydrogen bond dissociation energy and the dimer spectral parameters, including the average coefficient of collisional broadening of individual lines by water vapour and air. The manifestation of metastable states of the dimer in the observed spectra is assessed. The contribution of three possible pair states of water molecules to the second virial coefficient is evaluated over the broad range of temperatures. The work supports the significant role of the water dimer in atmospheric absorption and related processes.

Water dimers (H(2)O)(2) are believed to affect Earth's radiation balance and climate, homogeneous condensation, and atmospheric chemistry. Moreover, the pairwise interaction which binds the dimer appears to be of paramount importance for expounding a complete molecular description of the liquid and solid phases of water. However, there have been no secure, direct observations of water dimers at environmentally relevant temperatures despite decades of studies. We report the first unambiguous observation of the dimer spectrum recorded in equilibrium water vapor at room temperature.

The instrument and methods for measuring spectral parameters of discrete atmospheric lines and water-related continuum absorption in the millimeter wave range are described. The instrument is based on measurements of the Fabry-Pérot resonance response width using fast phase continuous scanning of the frequency-synthesized radiation. The instrument allows measurement of gas absorptions at the cavity eigenfrequencies ranging from 45 to 370 GHz with the highest to date absorption variation sensitivity of 4x10(-9) cm(-1). The use of a module of two rigidly bounded maximum identical resonators differing in length by exactly a factor of two allows accurate separation of the studied gas absorption and spectrometer baseline, in particular, the absorption by water adsorbed on the resonator elements. The module is placed in a chamber with temperature controlled between -30 and +60 degrees C, which permits investigation of temperature dependence of absorption. It is shown that systematic measurement error of discrete atmospheric line parameters does not exceed the statistical one and the achieved accuracy satisfies modern demands for the atmospheric remote sensing data retrieval. Potential systematic error arising from the neglect of the effect of water adsorption on mirror surfaces is discussed. Examples of studies of water and oxygen spectral line parameters as well as continuum absorption in wet nitrogen are given.

For the first time the 118-GHz line of the oxygen molecule was investigated in the laboratory under a real atmosphere. The experiment was carried out by modern resonator spectroscopy methods on the laboratory air at atmospheric pressure. The shape of the line under the real atmosphere was found to fit the Van Vleck-Weisskopf profile within experimental accuracy. The air broadening parameter value was defined as 2.14+/-0.07 MHz/Torr. The observed atmosphere oxygen line central frequency was found to be shifted down at about 150 MHz from the line center measured at low pressures, which gives a value of -0.19+/-0.08 MHz/Torr for the air shift parameter. A comparison with previous investigations is presented and reprocessing of some experimental results of other authors was carried out. Results of reprocessing agree with the findings of the present paper. Copyright 2001 Academic Press.