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Measurements of the oxygen diffusivity of ceramic samples of the mixed ionic electronic conductor La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF6428) have shown the appearance of grain boundary tails in diffusion profiles at temperatures below 600 °C. Analysis of the tails yields values of the grain boundary diffusion products (Dgb δ). The activation enthalpies for the grain boundary and lattice diffusion are very close at 1.69 eV and 1.61 eV respectively, suggesting a common diffusion mechanism. Comparison with literature values on both lattice and grain boundary diffusion products have shown that values of Dgb δ obtained for LSCF6428 are the highest yet recorded for any oxide material. The reasons for this high value are discussed, including the degree of nonstoichiometry of the parent lattice and the possible involvement of the twin boundaries found in these ceramic samples. [ABSTRACT FROM AUTHOR]

Purpose: Hypobaric hypoxic habitats are currently being touted as a potential solution to minimise decompression procedures in preparation for extra vehicular activities during future space missions. Since astronauts will live in hypoxic environments for the duration of such missions, the present study sought to elucidate the separate and combined effects of inactivity [simulated with the experimental bed rest (BR) model] and hypoxia on sleep characteristics in women., Methods: Twelve women (Age = 27 ± 3 year) took part in three 10-day interventions, in a repeated measures cross-over counterbalanced design: (1) normobaric normoxic BR (NBR), (2) normobaric hypoxic BR (HBR; simulated altitude of 4,000 m), and (3) normobaric hypoxic ambulatory (HAMB; 4,000 m) confinement, during which sleep was assessed on night 1 and night 10 with polysomnography. In addition, one baseline sleep assessment was performed. This baseline assessment, although lacking a confinement aspect, was included statistically as a fourth comparison (i.e., pseudo normobaric normoxic ambulatory; pNAMB) in the present study., Results: Hypoxia decreased sleep efficiency ( p = 0.019), increased N1% sleep ( p = 0.030), decreased N3 sleep duration ( p = 0.003), and increased apnea hypopnea index ( p < 0.001). BR impaired sleep maintenance, efficiency, and architecture [e.g., N2% sleep increased ( p = 0.033)]. Specifically, for N3% sleep, the effects of partial pressure of oxygen and activity interacted. Hypoxia decreased N3% sleep both when active (pNAMB vs HAMB; p < 0.001) and inactive (NBR vs HBR; p = 0.021), however, this decrease was attenuated in the inactive state (-3.8%) compared to the active state (-10.2%)., Conclusion: A 10-day exposure to hypoxia and BR negatively impacted sleep on multiple levels as in macrostructure, microstructure and respiratory functioning. Interestingly, hypoxia appeared to have less adverse effects on sleep macrostructure while the participants were inactive (bed ridden) compared to when ambulatory. Data were missing to some extent (i.e., 20.8%). Therefore, multiple imputation was used, and our results should be considered as exploratory., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Van Cutsem, Pattyn, Mairesse, Delwiche, Fernandez Tellez, Van Puyvelde, Lacroix, McDonnell, Eiken and Mekjavic.)

Surface reactivity and near-surface electronic properties of SrO-terminated SrTiO 3 and iron doped SrTiO 3 were studied with first principle methods. We have investigated the density of states (DOS) of bulk SrTiO 3 and compared it to DOS of iron-doped SrTiO 3 with different oxidation states of iron corresponding to varying oxygen vacancy content within the bulk material. The obtained bulk DOS was compared to near-surface DOS, i.e. surface states, for both SrO-terminated surface of SrTiO 3 and iron-doped SrTiO 3 . Electron density plots and electron density distribution through the entire slab models were investigated in order to understand the origin of surface electrons that can participate in oxygen reduction reaction. Furthermore, we have compared oxygen reduction reactions at elevated temperatures for SrO surfaces with and without oxygen vacancies. Our calculations demonstrate that the conduction band, which is formed mainly by the d-states of Ti, and Fe-induced states within the band gap of SrTiO 3 , are accessible only on TiO 2 terminated SrTiO 3 surface while the SrO-terminated surface introduces a tunneling barrier for the electrons populating the conductance band. First principle molecular dynamics demonstrated that at elevated temperatures the surface oxygen vacancies are essential for the oxygen reduction reaction.

Sleep disturbances are the main health complaints from personnel deployed in Antarctica. The current paper presents a systematic review of research findings on sleep disturbances in Antarctica. The available sources were divided in three categories: results based on questionnaire surveys or sleep logs, studies using actigraphy, and data from polysomnography results. Other areas relevant to the issue were also examined. These included chronobiology, since the changes in photoperiod have been known to affect circadian rhythms, mood disturbances, exercise, sleep and hypoxia, countermeasure investigations in Antarctica, and other locations lacking a normal photoperiod. Based on the combination of our reviewed sources and data outside the field of sleep studies, or from other geographical locations, we defined hypotheses to be confirmed or infirmed, which allowed to summarize a research agenda. Despite the scarcity of sleep research on the Antarctic continent, the present review pinpointed some consistent changes in sleep during the Antarctic winter, the common denominators being a circadian phase delay, poor subjective sleep quality, an increased sleep fragmentation, as well as a decrease in slow wave sleep. Similar changes, albeit less pronounced, were observed during summer. Additional multidisciplinary research is needed to elucidate the mechanisms behind these changes in sleep architecture, and to investigate interventions to improve the sleep quality of the men and women deployed in the Antarctic., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Telemedicine is a valid alternative to face-to-face patient care in many areas. However, the opinion of all stakeholders is decisive for successful adoption of this technique, especially as telemedicine expands into novel domains such as emergency teleconsultations during ambulance transportation and chronic care at home., Objective: We evaluate the viewpoints of the broad public, patients, and professional caregivers in these situations., Methods: A 10-question survey was developed and obtained via face-to-face interviews of visitors at the Universitair Ziekenhuis Brussel (UZB). The online questionnaire was also distributed among professional caregivers via the intranet of the UZB and among the broad public using social media., Results: In total, 607 individuals responded to the questionnaire, expressing a positive opinion regarding telemedicine for in-ambulance emergency treatment and for chronic care at home. Privacy issues were not perceived as relevant, and most respondents were ready to participate in future teleconsultations. Lack of telecommunication knowledge (213/566, 37.6%) was the only independent factor associated with rejection of telemedicine at home and respondents via social media (250/607, 41.2%) were less concerned about privacy issues than respondents via face-to-face interviews (visitors, 234/607, 38.6%). The visitors were more positive towards in-ambulance telemedicine and more likely to agree with future participation in teleconsultations than respondents via social media., Conclusions: The broad public, professional caregivers, and patients reported a positive attitude towards telemedicine for emergency treatment during ambulance transportation and for chronic care at home. These results support further improvement of telemedicine solutions in these domains.

Background: In-ambulance telemedicine is a recently developed and a promising approach to improve emergency care. We implemented the first ever 24/7 in-ambulance telemedicine service for acute stroke. We report on our experiences with the development and pilot testing of the Prehospital Stroke Study at the Universitair Ziekenhuis Brussel (PreSSUB) to facilitate a wider spread of the knowledge regarding this technique., Methods: Successful execution of the project involved the development and validation of a novel stroke scale, design and creation of specific hardware and software solutions, execution of field tests for mobile internet connectivity, design of new care processes and information flows, recurrent training of all professional caregivers involved in acute stroke management, extensive testing on healthy volunteers, organisation of a 24/7 teleconsultation service by trained stroke experts and 24/7 technical support, and resolution of several legal issues., Results: In all, it took 41 months of research and development to confirm the safety, technical feasibility, reliability, and user acceptance of the PreSSUB approach. Stroke-specific key information can be collected safely and reliably before and during ambulance transportation and can adequately be communicated with the inhospital team awaiting the patient., Conclusion: This paper portrays the key steps required and the lessons learned for successful implementation of a 24/7 expert telemedicine service supporting patients with acute stroke during ambulance transportation to the hospital., (© 2016 S. Karger AG, Basel.)

In order to determine optimal training parameters for robot-assisted treadmill walking, it is essential to understand how a robotic device interacts with its wearer, and thus, how parameter settings of the device affect locomotor control. The aim of this study was to assess the effect of different levels of guidance force during robot-assisted treadmill walking on cortical activity. Eighteen healthy subjects walked at 2 km.h-1 on a treadmill with and without assistance of the Lokomat robotic gait orthosis. Event-related spectral perturbations and changes in power spectral density were investigated during unassisted treadmill walking as well as during robot-assisted treadmill walking at 30%, 60% and 100% guidance force (with 0% body weight support). Clustering of independent components revealed three clusters of activity in the sensorimotor cortex during treadmill walking and robot-assisted treadmill walking in healthy subjects. These clusters demonstrated gait-related spectral modulations in the mu, beta and low gamma bands over the sensorimotor cortex related to specific phases of the gait cycle. Moreover, mu and beta rhythms were suppressed in the right primary sensory cortex during treadmill walking compared to robot-assisted treadmill walking with 100% guidance force, indicating significantly larger involvement of the sensorimotor area during treadmill walking compared to robot-assisted treadmill walking. Only marginal differences in the spectral power of the mu, beta and low gamma bands could be identified between robot-assisted treadmill walking with different levels of guidance force. From these results it can be concluded that a high level of guidance force (i.e., 100% guidance force) and thus a less active participation during locomotion should be avoided during robot-assisted treadmill walking. This will optimize the involvement of the sensorimotor cortex which is known to be crucial for motor learning.

A variety of bifunctional crosslinking agents have been explored for stabilizing microtubule shuttles used for the active transport of nanomaterials in artificial environments. Crosslinking agents that target amine residues form intertubulin crosslinks that produce crosslinked microtubules (CLMTs) with structural and functional lifetimes that can be up to four times as long as those achieved with taxol stabilization. Such CLMTs are stable at temperatures down to -10 degrees C, are resistant to depolymerization induced by metal ions such as Ca2+, and yet continue to be adsorbed and transported by self-assembled monolayers containing the motor protein kinesin. However, crosslinkers that target cysteine residues depolymerize the MTs, probably by interfering with the guanosine triphosphate binding site. The impact of crosslink attributes, including terminal group chemistry, chain length, crosslink density, and specific location on the tubulin surface, on microtubule stability and functionality are discussed.