Popular SIR models and their modifications used to generate predictions about epidemics and, specifically, the COVID-19 pandemic, are inadequate. The aim of this study was to find the laws describing the probability of infection in a biological object. Using theoretical methods of research based on the probability theory, we constructed the laws describing the probability of infection in a human depending on the infective dose and considering the temporal characteristics of a given infection. The so-called generalized time-factor law, which factors in the time of onset and the duration of an infectious disease, was found to be the most general. Among its special cases are the law describing the probability of infection developing by some point in time t, depending on the infective dose, and the law that does not factor in the time of onset. The study produced a full list of quantitative characteristics of pathogen virulence. The laws described in the study help to solve practical tasks and should lie at the core of mathematical epidemiological modeling.

Ensuring safety of the facilities employing radiation and nuclear hazardous technologies is a priority task for medical organizations serving these facilities. To perform safely at their jobs, it is important for the personnel of nuclear facilities (NF) to have their central nervous systems functioning flawlessly. Certain categories of nuclear industry workers are required to undergo compulsory annual medical examinations (ME) and psychophysiological examinations. This study aimed to develop a concept of psychophysiological examination of NF personnel allowing to assess the central nervous system's functional status. The study involved three groups of nuclear corporation employees (male) counting 720, 364 and 24 people aged from 46 ± 5.3 to 49 ± 6.1 years. The report describes the suggested concept of psychophysiological examination of the specified category of workers, discusses goals, objectives and the procedure of such an examination at all stages of compulsory ME, covers the developed hardware and software sets. The proposed methodological approach is evaluated through consideration of the results of psychophysiological examination of the specified category of workers.

COVID-19 belongs to the group of acute respiratory infections and it is often complicated with pneumonia. This study aimed to investigate manifestations of community-acquired pneumonia (CAP) epidemic process during the COVID-19 epidemic in the Russian Federation. We analyzed the official statistical data reporting the incidence of CAP in the Russian Federation in 2013–2020 and incidence of COVID-19 as registered in March–July 2020. The mean average annual CAP incidence rate that we calculated and the 2020 CAP incidence prediction allowed assessing the relationship between CAP and COVID-19. It is shown that the long-term dynamics of the incidence of CAP in the Russian Federation is characterized by a pronounced upward trend with an average annual growth rate of 6.4%. The share of adult population among the CAP cases is the largest; on average, it is 64.7% (95% CI [63.1; 66.3]). In 2020, against the background of SARS-CoV-2 circulation, the discrepancy between the actual incidence of CAP and the predicted figures reached and exceeded 558% (in July 2020). As the COVID-19 epidemic developed, the incidence of CAP was registered to increase. There was established a direct and significant correlation between the incidence of CAP and  COVID-19 (r_xy= 0.932; p <0.01).

Low molecular weight compounds targeting chaperone proteins Hsp90 and Hsp70 have opened up a new avenue in the therapy of neoplasms. In 2020, we tested 3 Hsp70 inhibitors from the class of 4-aminopiperidine derivatives for their antitumor activity on in vivo models. The list of the tested compounds included N-(2-chlorobenzyl)-N-ethyl-1-(2-(methylthio)pyrimidin-4-yl)piperidin-4-amine (compound 1), 4-((methyl(1-(2-(methylthio)pyrimidin-4-yl) piperidin-4-yl)amino)methyl) benzonitrile (compound 2) and N-(2,6- dichlorobenzyl)-1-(1-(2-(ethylthio)pyrimidin-4-yl)piperidin-4-yl)-N-methylmethaneamine (compound 3). The aim of this study was to compare the efficacy of 4-aminopiperidine derivatives in vivo using the models of transplantable murine L1210 lymphocytic leukemia and B16 melanoma. Compounds 2 and 3 used in combination with cyclophosphamide exhibited high cytotoxic activity (р = 0.05) against L1210 leukemia (an 80-82% increase in survival time) and B16 melanoma (98-99.7% tumor growth delay). For L1210 lymphocytic leukemia, compounds 2 and 3 used in combination with cyclophosphamide fell into the low (+) therapeutic potential category. For B16 melanoma, compounds 1, 2 and 3 used in combination with cyclophosphamide fell into either low (+) or moderate (++) therapeutic potential categories. On the whole, the tested doses of the compounds used in combination with cyclophosphamide hold promise for the therapy of L1210 leukemia and B16 melanoma in mouse models. Our findings confirm the potential of low molecular weight Hsp70 inhibitors for combination chemotherapy against cancer.

Wind affects functional state and health of human beings. Physical activity mitigates the risk of hypothermia, but not the discomfort felt in cold winds. Moreover, there appears a risk of body cooling and frostbite. This study aimed to assess the risk to health of a human being associated with the wind chill factor index in the various climatic zones of a Russian region. The calculation relied on the mean monthly daily temperature and wind speed values, minimum temperature and maximum wind values registered in the subarctic and continental climate zones during the two climatological normals determination observation periods, 1961- 1990 (second period) and 1991–2020 (third period). In the third period, a significant decrease in wind strength was registered in the subarctic (8 months) and temperate continental (9 months) climates. The mean monthly temperatures increased in April by 3.5 °C (p = 0.006), April–June by 4.05 °C (p = 0.001) and 3.9 °C (p = 0.001). The maximum wind in the subarctic climate did not change, in the temperate continental zone it decreased within 9 months; the minimum temperature increased in 4 and 1 months. In the subarctic zone, the mean temperature and wind values made the ambient conditions uncomfortable for 6 months (versus 7), with one characterized as "extremely cold"; the cold exposure risk decreased during the "very cold" period; in the temperate climate zone, the potentially uncomfortable conditions period lasted for 4 months (versus 6). With wind at the maximum and temperature at the minimum, in the subarctic climate, the weather remained severe for 8 months a year in each of the determination periods ("uncomfortable, chilly" — 2 months, "cold, skin surface hypothermia" — 1 month, "extremely cold, possible hypothermia of the exposed parts of the body in 10 minutes" — 5 months); in the temperate continental climate zone, it was severe for 5 months of each year ("uncomfortable, chilly" — 2 months, "cold, skin surface hypothermia" — 3 month).

The diagnosis and treatment of diseases caused by the exposure of human epigenome to environmental pollutants are hampered by epigenomic plasticity, instability and nonlinear cumulative effects of existing transcriptional regulatory pathways. DNA methylation, histone acetylation and histone methylation are the best studied epigenetic modifications. There are simple methods for assessing genome-wide DNA methylation; however, it is essential to study the epigenetic landscape in detail in order to uncover the mechanisms underlying pollutant-associated effects on the organism. This prompts researchers to employ whole-genome sequencing and analyze vast arrays of sequencing data that can be compiled into extensive databases of human and animal epigenomes. Drugs developed to counter epigenetic disorders neutralize their symptoms and either affect epigenetic modifications across the entire genome or regulate the activity of enzymes that play a critical role in such disorders. Promise is held by targeted genome editing methods supported by modern technologies that are undergoing preclinical trials. This review discusses the potential of modern science in the diagnosis and treatment of diseases caused by environmental pollutants.

In their line of duty, firefighters and rescuers are exposed to a combination of adverse factors, which necessitates monitoring their health. This review covers the most common variants of urticaria associated with high-risk occupations, such as cholinergic urticaria, food-induced anaphylaxis and exercise-induced urticaria, cold and stress-induced urticaria. The analysis includes the relevant research results published up to 2020; the discussion outlines the possible pathogenesis mechanisms of chronic urticaria.

The 67-th Session of the United Nations Scientific Committee on the Effects of the Atomic Radiation (UNSCEAR) took place in the form of videoconferences during 2-6 November 2020. Within the framework of the meetings of the Working group and subgroups the documents of the following projects were discussed: R.741 «Evaluation of medical exposure to ionizing radiation»; R.742 «Levels and effects of radiation exposure due to the accident at the Fukushima Daiichi nuclear power station: implications of information published since the UNSCEAR 2013 report»; R.743 «Biological mechanisms relevant for the inference of cancer risks from low- dose and low dose rate radiation»; R.744 «Evaluation of occupational exposure to ionizing radiation»; R.745 «Second primary cancer after radiotherapy»; R.746 «Epidemiological studies of radiation and cancer»; R.747 «Evaluation of public exposures to ionizing radiation from natural and man-made sources»; Project 67/7 «Implementation of the Committee's strategy to improve collection, analysis and dissemination of data on radiation exposure». The Committee also discussed the future research program (2020–2024); report to the UN General Assembly; public outreach activity including the strategy for the period 2020–2024.

This article describes a case of Paget-Schroetter syndrome in a female water polo player. The condition was associated with strenuous exercise. The initial treatment strategy was limited to a 14-day heparin regimen followed by a course of diosmin and sulodexide. The article discusses the high risk of post-thrombotic syndrome in this cohort of patients and the rationale for a surgical intervention.