Aim. To study the capability of applying the method of acoustic analysis of respiration (bronchophonography) in the diagnosis of hyperventilation syndrome and mild bronchial asthma and in differential diagnosis between them. Methods. 97 subjects were examined (35 men and 62 women, average age 36.4±13.4 years), divided into the groups: control (healthy subjects) - 38 subjects (18 men and 20 women, average age 33.6±14.0 years), patients with mild bronchial asthma - 37 subjects (12 men and 25 women, average age 40.7±13.7 years), patients with hyperventilation syndrome - 22 subjects (5 men and 17 women, average age 35.0±12.6 years). All patients, except for general clinical examination, underwent spirometry, bronchophonography and Nijmegen questionnaire. Results. Acoustic breathing patterns of all groups were formed, spirometric and bronchophonographic indicators were analyzed. Bronchophonography revealed significant intergroup differences in different frequency ranges in groups of patients with bronchial asthma and hyperventilation syndrome as well as the absence of those between healthy individuals and patients with hyperventilation syndrome. At the same time, the data of spirometry did not allow differentiation of mild bronchial asthma and hyperventilation syndrome and in most cases did not differ from those of healthy individuals. Conclusion. Spirometry cannot serve as a reliable diagnostic criterion in the diagnosis and differential diagnosis of hyperventilation syndrome and mild bronchial asthma; differences in acoustic indices of respiration in bronchophonography allow such differentiation.

Objective. To assess the influence of periodic limb movements in sleep on the incidence of acute cardiovascular events. Design and methods. Fifty-six participants aged 60–75 years were included in the study. Eligibility criteria included no history of acute cardiovascular events and the presence of 1 or more risk factors for cardiovascular diseases. Nocturnal actigraphy and cardiorespiratory monitoring were performed. Patients with apnea/hypopnea index > 5/h were excluded (n = 6). Based on periodic limb movements index (PLMI) two groups were formed: main (PLMI ≥ 15/h, n = 26) and controls (PLMI < 15/h, n = 24). The groups were prospectively observed during 1 year. The endpoints of the study were cases of acute cardiovascular events. Results. Despite the similar prevalence of common risk factors for cardiovascular diseases in two groups, the patients with PLMI ≥ 15/h have a higher incidence of ischemic stroke within 1 year (odds ratio 1,07). Conclusions. Elevated PLMI might be regarded as a potential predictor for higher risk for ischemic stroke. Nevertheless, further investigations in the field are needed.

Objective. The research objective is to develop a mathematical model of a thermoelectric semiconductor system to visualize the temperature fields of objects and study the thermophysical internal processes. Methods. A thermoelectric semiconductor system was developed for visualizing the temperature fields of flat objects using a liquid crystal film. Its feature is to increase the accuracy of measurements due to a more accurate coupling of the object and the device. A mathematical simulation of the system was performed based on the solution of a dynamic two-dimensional heat conduction problem with local heat sources and sinks over the area of a liquid crystal film. Results. Dependency graphs were obtained for the dependency of two-dimensional temperature distribution over the surface of the liquid crystal film in the presence of heat sources and sinks, the change in the cooling capacity, the cooling ratio, the supply voltage of the thermoelectric module on the temperature difference between the junctions for different values of the supply current. Conclusion. As a result of calculations, it was found that the color gamut of a liquid crystal film changed significantly in the presence of heat sources and sinks on its surface. During pre-calibration, the system allows visualization of the object temperature field and determines the value of its temperature at each point. Following the calculated data, it is determined that to ensure the entire operation of the thermoelectric semiconductor system, a standard thermoelectric module ICE-71 can be used with the following specifications: power range -16 to 35 W with an average temperature difference between the junctions -55 K, the supply current -28 A with a power consumption of 40 to 90 W, the cooling ratio is from 0.38 to 0.43.

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