In this study, we investigate the efficiency of laser radiation on oxyhemoglobin (HbO2) rate in blood vessels and its wavelength dependence. The results of in vivo experimental measurements of the laser-induced photodissociation of HbO2 in cutaneous blood vessels in the visible and near-infrared (IR) spectral range are presented. Arterial oxygen saturation (SpO2) was measured by a method of fingertip pulse oximetry, which is based on the measurement of the modulated pulse wave of the blood. The light irradiating the finger was provided by corresponding light-emitting diodes (LED) at 15 wavelengths in the 400-940 nm spectrum range. Statistical results with a value of p < 0.05 were viewed as being significant for all volunteers. The results show that there is a decrease in SpO2 in the blood under the influence of the transcutaneous laser irradiation. Three maxima in the spectral range (530, 600, and 850 nm) are revealed, wherein decrease in the relative concentration of SpO2 reaches 5 % ± 0.5 %. Near-IR radiation plays a dominant role in absorption of laser radiation by oxyhemoglobin in deeper layers of tissue blood vessels. The obtained data correlate with the processes of light propagation in biological tissue. The observed reduction in SpO2 indicates the process of photodissociation of HbO2 in vivo and may result in local increase in O2 in the tissue. Such laser-induced enrichment of tissue oxygenation can be used in phototherapy of pathologies, where the elimination of local tissue hypoxia is critical.

The effects of slight atmospheric pressure fluctuations (APFs) within two ranges of periods attributed mostly to far infrasound (3 s-120 s) and internal gravity waves (120 s-1200 s) on human behaviour related to injury occurrences, within the one-year interval, are examined. Special interest is paid to the analysis of combined effects of APFs and geomagnetic activity (GMA) attributed to low and moderate levels. The relations between the daily number of emergency transport events due to sport injuries (EEI) and daily mean of APF integral amplitudes within the two ranges (DHAI and DHAG, resp.) along with the planetary geomagnetic index Ap are analysed using the regression models based on categorization. As shown, the high DHAI is a rather strong meteorotropic factor, being of relevance to increase in the incidence of sport injuries. The high DHAG appears to be of opposite sense on the background of low DHAI, promoting the decreased EEI number. The consideration of combined effects of the APF and GMA reveals that the negative effects of high DHAI are more pronounced in combination with low Ap levels. The results are discussed from the viewpoint of the necessity of further medico-meteorological studies using databases of most disturbed geophysical conditions.

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Background. As widely known, the geomagnetic field intensity does change abruptly during global magnetic disturbances specified as magnetic storms. Those are due to the changing solar activity influencing solar wind parameters and the state of the magnetosphere. This chain of physical processes with their origin in the Sun is described as the space weather. To understand the space weather effects in the environment is most important since those are related to the biosphere as well. Namely, the low-frequency geomagnetic field dynamics, linked with space weather conditions, seems to be a quite probable factor influencing both the pathological and functional state of a human being and biological objects, in general, during magnetic storms. Objective. In this study, the dynamics of an oxygen saturation parameter in human arterial blood is analyzed with regard to extreme space weather when magnetic storms occur. Methods. Experimental setup for measuring changes of the relative concentration of oxyhemoglobin in arterial blood (saturation of arterial blood with oxygen), is a pulse oximeter-spectrophotometer. Measurements were carried out using pulse-oximetry sensor covering the first phalanx of a finger, and laser radiation was directed to the side of the second phalanx. The He-Ne laser with a wavelength of 632 nm was used as a source of electromagnetic radiation. Observational values of the geomagnetic field with a high-time resolution (1-sec) are obtained from the midlatitude Hurbanovo Geomagnetic Observatory (Slovak Republic). Deviations/oscillation ranges regarding the average value were calculated at all frequencies, and low pass filter was applied from the "Seewave-1.7.6" package (F-filter) for frequencies of 0.1, 0.5, 0.01, 0.05, 0.001, and 0.0001 Hz. The data on magnetic storms for 2015 were derived from the file of Kyoto Geomagnetic Center which indicated the dates and the amplitudes of magnetic storms on the Earth. Results. The following variables were analyzed: the average arterial oxygen saturation at the patient's rest, peak-to-peak value of saturation, changes in the average oxygen saturation under laser radiation. A group of 33 persons was daily monitored from March 30, 2015, to May 25, 2015. In the presence of Earth's magnetic field disturbances, the average value of arterial oxygen saturation at the state of rest in 29 persons out of 33 was 93.9 ± 0.9%, peak-to-peak value of oxygen was 1.25 ± 0.24%, and the change in the average arterial oxygen saturation under laser radiation made up 2.34 ± 0.41%. In 4 persons under study the peak-to-peak value of saturation at rest did not differ from the case of the undisturbed geomagnetic field. Conclusions. The results of this study of some blood parameters, namely the oxygen saturation (and oxygenetion) value of the arterial blood and its dynamics due to exposed laser radiation in case of both the undisturbed and disturbed GMF, can be summarized as follows: the decrease of the blood oxygenation in case of the disturbed GMF (magnetic storm conditions) is quite appa...

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