A group of authors has developed a multilevel mathematical model that focuses on functional disorders in a human body associated with various chemical, physical, social, and other factors. At this point, the researchers have come up with structure, basic definitions and concepts of a mathematical model at the “macrolevel” that allow describing processes in a human body as a whole. Currently we are working at the “mesolevel” of organs and systems. Due to complexity of the tasks, this paper deals with only one meso-fragment of a digestive system model. It describes some aspects related to modeling multiphase flow in the antroduodenal portion of the gastrointestinal tract. Biochemical reactions, dissolution of food particles, and motor, secretory, and absorbing functions of the tract are taken into consideration. The paper outlines some results concerning influence of secretory function disorders on food dissolution rate and tract contents acidity. The effect which food density has on inflow of food masses from a stomach to a bowel is analyzed. We assume that the future development of the model will include digestive enzymes and related reactions of lipolysis, proteolysis, and carbohydrates breakdown.
In the paper there are described examples of the practical implementation of methodological approaches to the assessment of evolution of the health risk under exposure to a set of environmental factors. In the hygienic assessment of the dynamics of health risks for citizens, residing near a major airport (about 500 takeoffs and landings per day), there were revealed high risks of disorders of the cardiovascular and nervous system. The difference between the risks emerging under the exposure and without the impact of the factors peculiar to the airport was shown to increase with the age significantly, accounting for 5-year period, 1,2% of the exposure; over 20 years - 8-10%, and during the period of 50 years - more than 20%. There were obtained results describing the dynamics of the gain of risks for the population of all ages, the structure of risks in the different periods of the human life. Outputs of evolutionary modeling allowed to identify critical periods of exposure to factors for which the qualitative changes of levels of risk take place. This is important in justifying the order ofpriorities and urgency of sanitary hygienic measures for risk management. The development of methodological approaches lies in the plane of the refinement of mathematical models, improvement of methods for the assessment of the intensity and duration of exposure, taking into account features of the combined impacts of hazard factors of different nature.
Aim: scientific forecasting toxicity and evaluation potential hazard of the biological action of aluminum oxide nanoparticles for human health. Methods: forecasting toxicity and assessment of potential hazards was carried out according to the results of forecasting-analytical modeling complexes of indicators characterizing physico-chemical, molecular biological, biochemical, cytological and ecological properties with calculation coefficients of hazard (D) and incompleteness of data evaluation (U) of nanoscale aluminum. Own research on the establishment of size and shape of nanomaterial were performed using dynamic laser light scattering and scanning electron microscopy, specific surface area were determined by the method of Brunauer, Emmet and Taylor. Results: aluminum oxide nanoparticles have a size of 30-40 nm, specific surface area 113 m2/g insoluble in water, superhydrophobic, have an effective positive charge. They are have the ability to generate reactive oxygen, damage DNA, disrupt protein expression, depolarize cell membrane, cause morphological changes and cell death, disturb the mitochondrial metabolism, impact on proteomic and metabolic profiles, inducing pro-inflammatory cytokine interleikin-1, ß, tumor necrosis factor and cluster of differentiation 86, 80 and 40. Besides, the material under investigation has such long-term effects of aaction: carcinogenicity and immunotoxicity. Conclusions: based on the results of forecasting modeling, established: aluminum oxide nanoparticles have a high degree of potential hazard for human health (coefficient D = 2,202 that is included in the range 1,780-2,449 and correspond to a high degree of potential hazard). The results indicate necessity for toxicological studies and preparation toxicological-hygienic characteristics of aluminum oxide nanoparticles at various routes of intake for development of effective preventive measures of negative impact on workers and consumers in contact with nanoproducts.
Manganese oxides have been synthesized by the interaction of Mn 2+ and Mn in the presence of nanoreactors: cetyltrimethylammonium bromide micelles that were not present in the final product composition. The synthesized substance is investigated using scanning electron microscopy, X-ray diffraction analysis, dynamic light scattering, the Brunauer-Emmett-Teller method, and the method of Barrett-Joyner-Halenda. It is determined that the substance under examination is a filamentous nanometer-scale material with a cross-section size up to 100 nm. The acute inhalation toxicity study is performed according to the interstate standard using the method of acute-toxicity class determination (ATC method) (OECD, Test no. 436:2008, IDT). The ATC method allows us to see that synthesized nanosized manganese oxide has an acute toxicity property when inhaled as an aerosol. Upon 4-h exposure to Wistar rats weighing 190 ± 10g, CL 50 is 0.12 mg/L. The clinical picture of acute intoxication is characterized by irritation, neurotoxic effects, and respiratory depression. According to CL 50 (>0.05-0.5), mg/L criterion, synthesized nanosized manganese oxide belongs to hazard class 2 in accordance with Globally Harmonized System of Classification and Labelling of Chemicals (GHS).
The article presents an overview and summarizes the accumulated international and national experience, highlighting the formation and main stages of the development of the theoretical foundations and practical significance of the use of biomarkers in medico-ecological studies and evaluations in terms of influence of harmful chemical factors on the human organism. It is shown that in order to increase the effectiveness of evidentiary causal relationships of developing negative effects and modifying the mechanism of their development with the adverse effects of environmental factors, the need to expand scientific research in the field of biomarkers, their selection criteria, and justification of reference levels is becoming more urgent. In accordance with the opinion of experts from the Ad Hoc Collaborating Organizations on Biomarkers (UNEP, ILO and WHO), biomarkers of three classes were identified - exposure biomarkers, reflecting exposure, sensitivity, characterizing the degree of organism susceptibility to exposure and markers of negative effects, indicating the development of the body's response to the effects of risk factors. Based on the currently existing international approaches and taking into account national competencies, a characteristic was given and the practical significance of each class of biological markers was shown when solving problems of substantiating cause-effect relationships in the system «environment - human health» and making adequate management decisions.
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