Composition, crystallization conditions and genesis of sulfide-saturated parental melts of olivine-phyric rocks from Kamchatsky Mys (Kamchatka, Russia)

Highlights • Parental melts of sulfide-bearing KM rocks have near primary MORB-like composition. • Crystallization of these S-saturated melts occurred in near-surface conditions. • Extensive fractionation and crustal assimilation are not the causes of S-saturation. • S content in melts can be restored by accounting for daughter sulfide globules. Abstract Sulfide liquids that immiscibly separate from silicate melts in different magmatic processes accumulate chalcophile metals and may represent important sources of the metals in Earth's crust for the formation of ore deposits. Sulfide phases commonly found in some primitive mid-ocean ridge basalts (MORB) may support the occurrence of sulfide immiscibility in the crust without requiring magma contamination and/or extensive fractionation. However, the records of incipient sulfide melts in equilibrium with primitive high-Mg olivine and Cr-spinel are scarce. Sulfide globules in olivine phenocrysts in picritic rocks of MORB-affinity at Kamchatsky Mys (Eastern Kamchatka, Russia) represent a well-documented example of natural immiscibility in primitive oceanic magmas. Our study examines the conditions of silicate-sulfide immiscibility in these magmas by reporting high precision data on the compositions of Cr-spinel and silicate melt inclusions, hosted in Mg-rich olivine (86.9–90 mol% Fo), which also contain globules of magmatic sulfide melt. Major and trace element contents of reconstructed parental silicate melts, redox conditions (ΔQFM = +0.1 ± 0.16 (1σ) log. units) and crystallization temperature (1200–1285 °C), as well as mantle potential temperatures (~1350 °C), correspond to typical MORB values. We show that nearly 50% of sulfur could be captured in daughter sulfide globules even in reheated melt inclusions, which could lead to a significant underestimation of sulfur content in reconstructed silicate melts. The saturation of these melts in sulfur appears to be unrelated to the effects of melt crystallization and crustal assimilation, so we discuss the reasons for the S variations in reconstructed melts and the influence of pressure and other parameters on the SCSS (Sulfur Content at Sulfide Saturation)

In Memoriam: Roman M. Baevsky (1928-2020), a life in autonomic space medicine

Roman M. Baevsky, a dedicated scientist, compassionate physician, beloved mentor, and dear friend left us on May 31, 2020 at the age of 91 years. He had served as chief researcher at the scientific center of the Russian Federation—Institute of Biomedical Problems of the Russian Academy of Sciences (IBMP). Throughout his career, his work was focused on autonomic cardiovascular control mechanisms and how they are challenged in extreme environments, particularly during space travel. Moreover, he developed the concept that non-invasive cardiovascular autonomic testing could identify individuals at increased risk before symptoms occurred to guide preventive measures

Microgravity: an ideal environment for cardiac force measuring

In the article main principles of ballistocardiography are considered. Special attention is paid to registration of the spatial ballistocardiogramm. There exist two principles of ballistocardiography: dynamic and seismic. In the event of dynamic ballistocardiography body displacements align to an extent with shifting of the general center of body gravity. Ideal conditions for ballistocardiogram acquisition could be reached if rigidity of internal body relations had an infinitely large value, while rigidity of external relations was nearing the zero. Then displacements of the entire body would depend only on the forces imparted by the cardiovascular system. Microgravity is the only environment providing these ideal conditions for ballistocardiography. Microgravity allows effective application of the dynamic BCG principle to recording pulse-induced body movements corresponding to the center of mass displacements. This kindled interest of the first researchers in space medicine in ballistocardiographic investigations during space flight. Since free flying requires enough space, the investigations became possible only with construction of orbital stations. The first in-space ballistocardiogram was recorded on December 26, 1977 from Yu. Romanenko, commander of the first expedition to the Russian OS Salyut-6. The data about ballistocardiographic researches at orbital stations Salyut and MIR which were conducted to 70-90th years is presented. The first attempt the spatial ballistocardiogramm registration has been made in 1984 during the Soviet - Indian flight on OS Salyut-7. The first records spatial ballistocardiogramm have been made during space experiment "Vector" on OS the MIR in 1990. New experiment "Cardiovector" on the ISS is being prepared for 2014-16

The effects of long-term microgravity on autonomic regulation of blood circulation in crewmembers of the international space station

The article presents the results of space experiment “Pneumocard”. The investigation involved all 25 Russian members of the ISS crew. The total of 226 sessions were made including 130 aboard the ISS, 50 prior to launch and 46 on return from mission. The objective was to study effects of the spaceflight factors on autonomic regulation of blood circulation, respiration and cardiac contractility during long-duration mission. The purpose was to secure new research data that would clarify our present view of adaptation mechanisms. Registered were the following signals: electrocardiogram, impedance cardiogram, seismic cardiogram, pneumotachogram, finger photoplethysmogram. A set of hard- and software was used. Autonomic regulation of blood circulation by HRV analysis was investigated. It was shown that at the onset of a space mission parasympathetic involvement in regulation increases typically with subsequent mobilization of additional functional reserve. It guided the development of a functional states mathematical model incorporating the established types of autonomic regulation. Our data evidence that the combination of HRV analysis, pre-nosology diagnosis and probabilistic estimate of the pathology risk can reinforce the medical care program in space missions

Central blood pressure and pulse wave velocity before and after six months in space

Purpose: Central aortic blood pressure and pulse wave velocity measurements are more predictive in terms of cardiovascular organ damage and risk compared with peripheral blood pressure. Such measurements, which have been proven useful in detecting early vascular aging on earth, have not been obtained after long term space missions. We applied an easy-to-perform, non-invasive, and wearable device to assess central blood pressure and other hemodynamic variables in cosmonauts. Methodology: We obtained oscillometric blood pressure measurement at the upper arm for determining central and peripheral blood pressure, heart rate, and pulse wave velocity (Mobil-O-Graph PWA, IEM, Germany) in eight cosmonauts before and after six months in space. In the supine position, we obtained multiple measurements at baseline (65-90 days before flight), four days (R+4) and eight days (R+8) after return. Written informed consent was given by all subjects. Results:Heart rate was 58.4±6:5 bpm at baseline, 70.3±5:2 bpm on R+4, and 66.2±9:0 bpm on R+8 (both p<0.05 compared with baseline). Peripheral systolic and mean blood pressure increased significantly on R+4 compared with baseline (systolic=119.9 ±13:4 vs. 134.1±19:7 mmHg, p<0.05; mean=97.7±10:8 vs. 107.7±12:1 mmHg; p<0.05) but did not differ from R+8. Analysis of central blood pressure revealed a non-significant rise in systolic, diastolic, and pulse pressure on R+4 (p=0.059, p=0.1, and p=0.175 respectively) and on R+8 (p=0.094, p=0.162, and p=0.209 respectively), with respect to baseline. After return, pulse wave velocity was non-significantly increased compared to baseline (baseline=6.6±0:8 m/s; R+4=7.2±0:8 m/s, p=0.141; R+8=7.1±0:5 m/s, p=0.176). All cosmonauts showed pulse wave velocities below 10 m/s, which is considered as the threshold heralding excess cardiovascular risk. Conclusion: The main finding is that, while heart rate and blood pressure were substantially increased following six months in space, central aortic blood pressure and pulse wave velocity did not show medically relevant oralchanges. The finding suggests that six months in space do not induce overt early vascular aging. Yet, larger and more long-term studies are required as space radiation may have a delayed effect on vascular healt

Central blood pressure and pulse wave velocity before and after six months in space

Purpose: Central aortic blood pressure and pulse wave velocity measurements are more predictive in terms of cardiovascular organ damage and risk compared with peripheral blood pressure. Such measurements, which have been proven useful in detecting early vascular aging on earth, have not been obtained after long term space missions. We applied an easy-to-perform, non-invasive, and wearable device to assess central blood pressure and other hemodynamic variables in cosmonauts. Methodology: We obtained oscillometric blood pressure measurement at the upper arm for determining central and peripheral blood pressure, heart rate, and pulse wave velocity (Mobil-O-Graph PWA, IEM, Germany) in eight cosmonauts before and after six months in space. In the supine position, we obtained multiple measurements at baseline (65-90 days before flight), four days (R+4) and eight days (R+8) after return. Written informed consent was given by all subjects. Results:Heart rate was 58.4±6:5 bpm at baseline, 70.3±5:2 bpm on R+4, and 66.2±9:0 bpm on R+8 (both p<0.05 compared with baseline). Peripheral systolic and mean blood pressure increased significantly on R+4 compared with baseline (systolic=119.9 ±13:4 vs. 134.1±19:7 mmHg, p<0.05; mean=97.7±10:8 vs. 107.7±12:1 mmHg; p<0.05) but did not differ from R+8. Analysis of central blood pressure revealed a non-significant rise in systolic, diastolic, and pulse pressure on R+4 (p=0.059, p=0.1, and p=0.175 respectively) and on R+8 (p=0.094, p=0.162, and p=0.209 respectively), with respect to baseline. After return, pulse wave velocity was non-significantly increased compared to baseline (baseline=6.6±0:8 m/s; R+4=7.2±0:8 m/s, p=0.141; R+8=7.1±0:5 m/s, p=0.176). All cosmonauts showed pulse wave velocities below 10 m/s, which is considered as the threshold heralding excess cardiovascular risk. Conclusion: The main finding is that, while heart rate and blood pressure were substantially increased following six months in space, central aortic blood pressure and pulse wave velocity did not show medically relevant oralchanges. The finding suggests that six months in space do not induce overt early vascular aging. Yet, larger and more long-term studies are required as space radiation may have a delayed effect on vascular healt

Big data analytics for enhanced clinical decision support systems during spaceflight

© 2017 IEEE. Recent advancements in the field of space medicine and technology have extended the boundaries of space travel, presenting humankind with the ability to explore undiscovered habitats. As humans embark on long range missions, adaptation mechanisms will be put to the test, challenging provision of medical care in space. To date, a vast amount of knowledge has been accumulated through a series of experiments, both in terrestrial simulation environments and space missions on the ISS. As a result, functional health state algorithm has been developed and validated by IBMP, to identify transitional states between health and disease. Significant limitations on provision of medical care in space are imposed due to retrospective data processing and analysis techniques. Some of these limitations can be addressed by the proposed instantiation of the functional state algorithm within the Online Analytics component of the Artemis platform, to enhance clinical decision support systems during spaceflight

An oscillometric approach in assessing early vascular ageing biomarkers following long-term space flights

Purpose: The environmental conditions in space, particularly exposure to cosmic radiation, coupled with decreased mobility, altered glucose metabolism, and hemodynamic changes may promote cardiovascular disease Therefore, we assessed early vascular aging markers and hemodynamics using a novel oscillometric blood pressure device. Methodology: In eight cosmonauts (46.5 ± 5.3 yrs, 77.6 ± 8.2 kg, 176 ± 6.2 cm, 7 men/1woman), we determined heart rate, peripheral blood pressure, central blood pressure, and pulse wave velocity in the supine position using an oscillometric brachial device coupled with transfer function analysis. We obtained measurements at baseline (65–90 days before flight) and four days (R+4) and eight days (R+8) after return from six months mission onboard the International Space Station. Results: Compared to baseline, heart rate increased significantly on R+4 (58.6 ± 6.4 vs. 70.3 ± 5.2 bpm) but did not differ on R+8. Central systolic blood pressure increased from 112.5 ± 13.5 on baseline to 125.6 ± 18.5 on Rþ4 and 121.6 ± 9.5 mmHg, albeit showing no statistical significance compared to baseline (p = 0.243/0.295). Peripheral diastolic and systolic as well as central diastolic blood pressure measurements followed this trend. Pulse wave velocity increased non-significantly from baseline (6.7 ± 0.8 m/s) to R+4 (7.2 ± 0.8 m/s, p = 0.499) and stayed elevated on R+8 (7.1 ± 0.5 m/s, p = 0.614). Conclusion: The important finding of our study is that six months in a near-earth orbit do not lead to clinically significant changes in early vascular ageing biomarkers. However, these findings cannot be extrapolated to the conditions encountered in deep space. Non-invasive testing of vascular biomarkers may have utility in detecting vascular risks during space travel at an early stage

Noninvasive investigation of the body functional state during night sleep in microgravity

The Sonocard experiment purpose was a noninvasive physiological signal recording from sleeping humans. In 2007-2012 the experiment was made by 22 Russian members of 17 missions to the International space station. Of the overall 302 experimental sessions 47 were performed pre, 215 in and 40 after flight. The seismographic technique was used to pick up cosmonaut’s body microoscillations induced by cardiac beats, respiration and motor activity. The flight Sonocard model is a midget device fitting into the T-shirt pocket. Heart rate variability analysis (HRV) was the major method of securing conclusive evidence on stress level and blood circulation autonomic regulation. We were first to trace reorganization of the autonomic regulation at the night time on different phases of long-duration space mission and pioneered a systematic investigation of the human body functional state during sleep. It was shown that in the absence of work loads and emotional stresses the central mechanisms of circulation regulation tend to increase their activities. The characteristic subsidence of breathing waves (HF) and growth of the vascular center (LF) portion within the HRV total spectrum by the end of flight were observed. Sleep quality in the course of long-duration missions was assessed. We succeeded in the first ever sleep assessment following operations in open space. The noninvasive physiological signal recording was recommended for use in spacecrew medical monitoring and ground-based experiments