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https://www.readbyqxmd.com/read/28734956/fast-carotid-artery-mr-angiography-with-compressed-sensing-based-three-dimensional-time-of-fight-sequence
#1
Bo Li, Hao Li, Li Dong, Guofu Huang
OBJECTIVE: In this study, we sought to investigate the feasibility of fast carotid artery MR angiography (MRA) by combining three-dimensional time-of-flight (3D TOF) with compressed sensing method (CS-3D TOF). MATERIALS AND METHODS: A pseudo-sequential phase encoding order was developed for CS-3D TOF to generate hyper-intense vessel and suppress background tissues in under-sampled 3D k-space. Seven healthy volunteers and one patient with carotid artery stenosis were recruited for this study...
July 19, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28727859/space-flight-associated-neuro-ocular-syndrome
#2
Andrew G Lee, Thomas H Mader, C Robert Gibson, William Tarver
New and unique physiologic and pathologic systemic and neuro-ocular responses have been documented in astronauts during and after long-duration space flight. Although the precise cause remains unknown, space flight-associated neuro-ocular syndrome (SANS) has been adopted as an appropriate descriptive term. The Space Medicine Operations Division of the US National Aeronautics and Space Administration (NASA) has documented the variable occurrence of SANS in astronauts returning from long-duration space flight on the International Space Station...
July 20, 2017: JAMA Ophthalmology
https://www.readbyqxmd.com/read/28720189/enhancing-the-meaningfulness-of-work-for-astronauts-on-long-duration-space-exploration-missions
#3
Thomas W Britt, Anton Sytine, Ashley Brady, Russ Wilkes, Rebecca Pittman, Kristen Jennings, Kandice Goguen
INTRODUCTION: Numerous authors have identified the stressors likely to be encountered on long duration space exploration missions (e.g., to Mars), including the possibility of significant crises, separation from family, boredom/monotony, and interpersonal conflict. Although many authors have noted that meaningful work may be beneficial for astronauts on these missions, none have detailed the sources of meaningful work for astronauts and how these sources may differ between astronauts...
August 1, 2017: Aerospace Medicine and Human Performance
https://www.readbyqxmd.com/read/28720182/ground-reaction-forces-during-reduced-gravity-running-in-parabolic-flight
#4
Peter Cavanagh, Andrea Rice, Molly Glauberman, Amanda Sudduth, Arien Cherones, Shane Davis, Michael Lewis, Andrea Hanson, Grier Wilt
BACKGROUND: Treadmills have been employed as both a form of exercise and a countermeasure to prevent changes in the musculoskeletal system on almost all NASA missions and many Russian missions since the early Space Shuttle flights. It is possible that treadmills may also be part of exercise programs on future Mars missions and that they may be a component of exercise facilities in lunar or Martian habitats. METHODS: In order to determine if the ambient gravity on these destinations will provide osteogenic effects while performing exercise on a treadmill, ground reactions forces (GRFs) were measured on eight subjects (six women and two men) running at 6 mph during parabolic flight in Martian and lunar gravity conditions...
August 1, 2017: Aerospace Medicine and Human Performance
https://www.readbyqxmd.com/read/28705999/the-effects-of-strict-prolonged-bedrest-on-cardio-respiratory-fitness-systematic-review-and-meta-analysis
#5
Mathias Ried-Larsen, Hugo Aarts, Michael J Joyner
The aim of this systematic review and meta-analysis (PROSPERO: CRD42017055619) was to assess the effects of strict prolonged bedrest (without counter measures) on V̇O2max and to explore sources of variation herein. Since 1949, 80 studies with a total of 949 participants (>90% males) have been published with data on strict bedrest and V̇O2max. The studies were conducted mainly in young participants (median age (interquartile range)) 24.5 (22.4 to 34.0) years. The duration of bedrest ranged from 1-90 days...
July 13, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28705441/spin-filtered-time-of-flight-k-space-microscopy-of-ir-towards-the-complete-photoemission-experiment
#6
G Schönhense, K Medjanik, S Chernov, D Kutnyakhov, O Fedchenko, M Ellguth, D Vasilyev, A Zaporozhchenko-Zymaková, D Panzer, A Oelsner, C Tusche, B Schönhense, J Braun, J Minár, H Ebert, J Viefhaus, W Wurth, H J Elmers
The combination of momentum microscopy (high resolution imaging of the Fourier plane) with an imaging spin filter has recently set a benchmark in k-resolution and spin-detection efficiency. Here we show that the degree of parallelization can be further increased by time-of-flight energy recording. On the quest towards maximum information (in earlier work termed "complete" photoemission experiment) we have studied the prototypical high-Z fcc metal iridium. Large partial bandgaps and strong spin-orbit interaction lead to a sequence of spin-polarized surface resonances...
July 6, 2017: Ultramicroscopy
https://www.readbyqxmd.com/read/28688391/crf-pepico-double-velocity-map-imaging-photoelectron-photoion-coincidence-spectroscopy-for-reaction-kinetics-studies
#7
Bálint Sztáray, Krisztina Voronova, Krisztián G Torma, Kyle J Covert, Andras Bodi, Patrick Hemberger, Thomas Gerber, David L Osborn
Photoelectron photoion coincidence (PEPICO) spectroscopy could become a powerful tool for the time-resolved study of multi-channel gas phase chemical reactions. Toward this goal, we have designed and tested electron and ion optics that form the core of a new PEPICO spectrometer, utilizing simultaneous velocity map imaging for both cations and electrons, while also achieving good cation mass resolution through space focusing. These optics are combined with a side-sampled, slow-flow chemical reactor for photolytic initiation of gas-phase chemical reactions...
July 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28680972/non-toxin-producing-bacillus-cereus-strains-belonging-to-the-b-%C3%A2-anthracis-clade-isolated-from-the-international-space-station
#8
Kasthuri Venkateswaran, Nitin K Singh, Aleksandra Checinska Sielaff, Robert K Pope, Nicholas H Bergman, Sandra P van Tongeren, Nisha B Patel, Paul A Lawson, Masataka Satomi, Charles H D Williamson, Jason W Sahl, Paul Keim, Duane Pierson, Jay Perry
In an ongoing Microbial Observatory investigation of the International Space Station (ISS), 11 Bacillus strains (2 from the Kibo Japanese experimental module, 4 from the U.S. segment, and 5 from the Russian module) were isolated and their whole genomes were sequenced. A comparative analysis of the 16S rRNA gene sequences of these isolates showed the highest similarity (>99%) to the Bacillus anthracis-B. cereus-B. thuringiensis group. The fatty acid composition, polar lipid profile, peptidoglycan type, and matrix-assisted laser desorption ionization-time of flight profiles were consistent with the B...
May 2017: MSystems
https://www.readbyqxmd.com/read/28678813/fine-scale-assessment-of-home-ranges-and-activity-patterns-for-resident-black-vultures-coragyps-atratus-and-turkey-vultures-cathartes-aura
#9
Amanda E Holland, Michael E Byrne, A Lawrence Bryan, Travis L DeVault, Olin E Rhodes, James C Beasley
Knowledge of black vulture (Coragyps atratus) and turkey vulture (Cathartes aura) spatial ecology is surprisingly limited despite their vital ecological roles. Fine-scale assessments of space use patterns and resource selection are particularly lacking, although development of tracking technologies has allowed data collection at finer temporal and spatial resolution. Objectives of this study were to conduct the first assessment of monthly home range and core area sizes of resident black and turkey vultures with consideration to sex, as well as elucidate differences in monthly, seasonal, and annual activity patterns based on fine-scale movement data analyses...
2017: PloS One
https://www.readbyqxmd.com/read/28674459/photo-excited-hot-carrier-dynamics-in-hydrogenated-amorphous-silicon-imaged-by-4d-electron-microscopy
#10
Bolin Liao, Ebrahim Najafi, Heng Li, Austin J Minnich, Ahmed H Zewail
Charge carrier dynamics in amorphous semiconductors has been a topic of intense research that has been propelled by modern applications in thin-film solar cells, transistors and optical sensors. Charge transport in these materials differs fundamentally from that in crystalline semiconductors owing to the lack of long-range order and high defect density. Despite the existence of well-established experimental techniques such as photoconductivity time-of-flight and ultrafast optical measurements, many aspects of the dynamics of photo-excited charge carriers in amorphous semiconductors remain poorly understood...
July 3, 2017: Nature Nanotechnology
https://www.readbyqxmd.com/read/28666311/fully-automatic-and-precise-data-analysis-developed-for-time-of-flight-mass-spectrometry
#11
S Meyer, A Riedo, M B Neuland, M Tulej, P Wurz
Scientific objectives of current and future space missions are focused on the investigation of the origin and evolution of the solar system with the particular emphasis on habitability and signatures of past and present life. For in situ measurements of the chemical composition of solid samples on planetary surfaces, the neutral atmospheric gas, and the thermal plasma of planetary atmospheres, the application of mass spectrometers making use of time-of-flight mass analysers is a technique widely used. However, such investigations imply measurements with good statistics and thus, a large amount of data to be analysed...
June 30, 2017: Journal of Mass Spectrometry: JMS
https://www.readbyqxmd.com/read/28653338/a-method-for-detailed-movement-pattern-analysis-of-tadpole-startle-response
#12
Kasra Zarei, Karen L Elliott, Sanam Zarei, Bernd Fritzsch, James H J Buchholz
Prolonged space flight, specifically microgravity, presents a problem for space exploration. Animal models with altered connections of the vestibular ear, and thus altered gravity sensation, would allow the examination of the effects of microgravity and how various countermeasures can establish normal function. We describe an experimental apparatus to monitor the effects of ear manipulations to generate asymmetric gravity input on the tadpole escape response. To perform the movement pattern analysis, an imaging apparatus was developed that uses a high-speed camera to obtain time-resolved, high-resolution images of tadpole movements...
June 27, 2017: Journal of the Experimental Analysis of Behavior
https://www.readbyqxmd.com/read/28649638/a-cubesat-centrifuge-for-long-duration-milligravity-research
#13
REVIEW
Erik Asphaug, Jekan Thangavelautham, Andrew Klesh, Aman Chandra, Ravi Nallapu, Laksh Raura, Mercedes Herreras-Martinez, Stephen Schwartz
We advocate a low-cost strategy for long-duration research into the 'milligravity' environment of asteroids, comets and small moons, where surface gravity is a vector field typically less than 1/1000 the gravity of Earth. Unlike the microgravity environment of space, there is a directionality that gives rise, over time, to strangely familiar geologic textures and landforms. In addition to advancing planetary science, and furthering technologies for hazardous asteroid mitigation and in situ resource utilization, simplified access to long-duration milligravity offers significant potential for advancing human spaceflight, biomedicine and manufacturing...
2017: NPJ Microgravity
https://www.readbyqxmd.com/read/28649633/latent-virus-reactivation-in-astronauts-on-the-international-space-station
#14
Satish K Mehta, Mark L Laudenslager, Raymond P Stowe, Brian E Crucian, Alan H Feiveson, Clarence F Sams, Duane L Pierson
Reactivation of latent herpes viruses was measured in 23 astronauts (18 male and 5 female) before, during, and after long-duration (up to 180 days) spaceflight onboard the international space station . Twenty age-matched and sex-matched healthy ground-based subjects were included as a control group. Blood, urine, and saliva samples were collected before, during, and after spaceflight. Saliva was analyzed for Epstein-Barr virus, varicella-zoster virus, and herpes simplex virus type 1. Urine was analyzed for cytomegalovirus...
2017: NPJ Microgravity
https://www.readbyqxmd.com/read/28649628/a-hitchhiker-s-guide-to-an-iss-experiment-in-under-9-months
#15
Andrei James Nadir, Kevin Sato
The International Space Station National Laboratory gives students a platform to conduct space-flight science experiments. To successfully take advantage of this opportunity, students and their mentors must have an understanding of how to develop and then conduct a science project on international space station within a school year. Many factors influence the speed in which a project progresses. The first step is to develop a science plan, including defining a hypothesis, developing science objectives, and defining a concept of operation for conducting the flight experiment...
2017: NPJ Microgravity
https://www.readbyqxmd.com/read/28649626/investigation-of-simulated-microgravity-effects-on-streptococcus-mutans-physiology-and-global-gene-expression
#16
Silvia S Orsini, April M Lewis, Kelly C Rice
Astronauts have been previously shown to exhibit decreased salivary lysozyme and increased dental calculus and gingival inflammation in response to space flight, host factors that could contribute to oral diseases such as caries and periodontitis. However, the specific physiological response of caries-causing bacteria such as Streptococcus mutans to space flight and/or ground-based simulated microgravity has not been extensively investigated. In this study, high aspect ratio vessel S. mutans simulated microgravity and normal gravity cultures were assessed for changes in metabolite and transcriptome profiles, H2O2 resistance, and competence in sucrose-containing biofilm media...
2017: NPJ Microgravity
https://www.readbyqxmd.com/read/28649625/the-effect-of-long-term-exposure-to-microgravity-on-the-perception-of-upright
#17
Laurence R Harris, Michael Jenkin, Heather Jenkin, James E Zacher, Richard T Dyde
Going into space is a disorienting experience. Many studies have looked at sensory functioning in space but the multisensory basis of orientation has not been systematically investigated. Here, we assess how prolonged exposure to microgravity affects the relative weighting of visual, gravity, and idiotropic cues to perceived orientation. We separated visual, body, and gravity (when present) cues to perceived orientation before, during, and after long-term exposure to microgravity during the missions of seven astronauts on the International Space Station (mean duration 168 days) and measuring perceived vertical using the subjective visual vertical and the perceptual upright...
2017: NPJ Microgravity
https://www.readbyqxmd.com/read/28649623/segregation-and-pattern-formation-in-dilute-granular-media-under-microgravity-conditions
#18
Eric Opsomer, Martial Noirhomme, Nicolas Vandewalle, Eric Falcon, Simon Merminod
Space exploration and exploitation face a major challenge: the handling of granular materials in low-gravity environments. Indeed, grains behave quite differently in space than on Earth, and the dissipative nature of the collisions between solid particles leads to clustering. Within poly-disperse materials, the question of segregation is highly relevant but has not been addressed so far in microgravity. From parabolic flight experiments on dilute binary granular media, we show that clustering can trigger a segregation mechanism, and we observe, for the first time, the formation of layered structures in the bulk...
2017: NPJ Microgravity
https://www.readbyqxmd.com/read/28618521/local-time-of-l%C3%A3-vy-random-walks-a-path-integral-approach
#19
Václav Zatloukal
The local time of a stochastic process quantifies the amount of time that sample trajectories x(τ) spend in the vicinity of an arbitrary point x. For a generic Hamiltonian, we employ the phase-space path-integral representation of random walk transition probabilities in order to quantify the properties of the local time. For time-independent systems, the resolvent of the Hamiltonian operator proves to be a central tool for this purpose. In particular, we focus on the local times of Lévy random walks (Lévy flights), which correspond to fractional diffusion equations...
May 2017: Physical Review. E
https://www.readbyqxmd.com/read/28590761/proteome-wide-adaptations-of-mouse-skeletal-muscles-during-a-full-month-in-space
#20
Georg Tascher, Thomas Brioche, Pauline Maes, Angèle Chopard, Donal O'Gorman, Guillemette Gauquelin-Koch, Stéphane Blanc, Fabrice Bertile
The safety of space flight is challenged by a severe loss of skeletal muscle mass, strength, and endurance that may compromise the health and performance of astronauts. The molecular mechanisms underpinning muscle atrophy and decreased performance have been studied mostly after short duration flights and are still not fully elucidated. By deciphering the muscle proteome changes elicited in mice after a full month aboard the BION-M1 biosatellite, we observed that the antigravity soleus incurred the greatest changes compared with locomotor muscles...
June 20, 2017: Journal of Proteome Research
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