Peculiarities of droplet evaporation under radiative and convective heating

We propose a new method for determining the rate of evaporation of a lone levitating droplet under the action of radiative heat flux. Results of experimental investigation of the evaporation rate of a droplet of distilled water heated by radiative and convective heat flux density within q = 0.25–1.5 W/cm2 are presented. Comparative analysis of the peculiarities of droplet evaporation under radiative and convective heating conditions is performe

Special aspects of the drop evaporation during radiant heating

The methods and results of an experimental study of the process of evaporation of a single stationary liquid drop upon radiant heat flux are presented. It is shown that the method of the drop fixation (levitation or fixing on the holder) slightly affects the rate of evaporation. A multiple increase in the rate of evaporation of drops of distilled water and ethyl alcohol is found when a colorant is introduced into the drop liquid to increase its absorption index

Assessment of Diagnostic Specificity of Anti-SARS-CoV-2 Antibody Tests and Their Application for Monitoring of Seroconversion and Stability of Antiviral Antibody Response in Healthcare Workers in Moscow

Anti-SARS-CoV-2 antibody testing is an efficient tool to assess the proportion of seropositive population due to infection and/or vaccination. Numerous test systems utilizing various antigen composition(s) are routinely used for detection and quantitation of anti-SARS-CoV-2 antibodies. We determined their diagnostic specificity using archived true-negative samples collected before the onset of the COVID-19 pandemic. Using test systems demonstrating 98.5–100% specificity, we assessed the dynamics of SARS-CoV-2 seroconversion and durability of anti-spike (S) antibodies in healthcare professionals (n = 100) working in Moscow during the first two cycles of the pandemic (May 2020 to June 2021) outside of the “red zone”. Analysis revealed a rapid increase in anti-SARS-CoV-2 seropositivity from 19 to 80% (19/100 and 80/100, respectively) due to virus exposition/infection; only 16.3% of seroconversion cases (13/80) were due to vaccination, but not the virus exposure, although massive COVID-19 vaccination of healthcare workers was performed beginning in December 2020. In total, 12.7% (8/63) remained positive for anti-SARS-CoV-2 IgM for >6 months, indicating unsuitability of IgM for identification of newly infected individuals. All except one remained seropositive for anti-S antibodies for >9 months on average. Significant (>15%) declines in anti-SARS-CoV-2 antibody concentrations were observed in only 18% of individuals (9/50). Our data on the high seropositivity rate and stability of anti-SARS-CoV-2 antibody levels in healthcare personnel working outside of the “red zone” indicate their regular exposition to SARS-CoV-2/an increased risk of infection, while a low frequency of vaccine-induced antibody response acquired after the start of vaccination points to vaccine hesitancy