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https://www.readbyqxmd.com/read/29347501/dust-coupling-parameter-of-radio-frequency-discharge-complex-plasma-under-microgravity-conditions
#1
D I Zhukhovitskii, V N Naumkin, A I Khusnulgatin, V I Molotkov, A M Lipaev
Oscillation of particles in a dust crystal formed in a low-pressure radio-frequency gas discharge under microgravity conditions is studied. Analysis of experimental data obtained in our previous study shows that the oscillations are highly isotropic and nearly homogeneous in the bulk of a dust crystal; oscillations of the neighboring particles are significantly correlated. We demonstrate that the standard deviation of the particle radius vector along with the local particle number density fully define the coupling parameter of the particle subsystem...
October 2017: Physical Review. E
https://www.readbyqxmd.com/read/29347360/incorporation-of-velocity-dependent-restitution-coefficient-and-particle-surface-friction-into-kinetic-theory-for-modeling-granular-flow-cooling
#2
Yifei Duan, Zhi-Gang Feng
Kinetic theory (KT) has been successfully used to model rapid granular flows in which particle interactions are frictionless and near elastic. However, it fails when particle interactions become frictional and inelastic. For example, the KT is not able to accurately predict the free cooling process of a vibrated granular medium that consists of inelastic frictional particles under microgravity. The main reason that the classical KT fails to model these flows is due to its inability to account for the particle surface friction and its inelastic behavior, which are the two most important factors that need be considered in modeling collisional granular flows...
December 2017: Physical Review. E
https://www.readbyqxmd.com/read/29339777/regulation-of-the-response-of-caenorhabditis-elegans-to-simulated-microgravity-by-p38-mitogen-activated-protein-kinase-signaling
#3
Wenjie Li, Daoyong Wang, Dayong Wang
The in vivo function of p38 mitogen-activated protein kinase (MAPK) signaling in regulating the response to simulated microgravity is still largely unclear. Using Caenorhabditis elegans as an assay system, we investigated the in vivo function of p38 MAPK signaling in regulating the response of animals to simulated microgravity and the underlying molecular mechanism. Simulated microgravity treatment significantly increased the transcriptional expressions of genes (pmk-1, sek-1, and nsy-1) encoding core p38 MAPK signaling pathway and the expression of phosphorylated PMK-1/p38 MAPK...
January 16, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29336212/simulated-microgravity-impairs-cardiac-autonomic-neurogenesis-from-neural-crest-cells
#4
Konstantinos E Hatzistergos, Zhijie Jiang, Krystalenia Valasaki, Lauro M Takeuchi, Wayne Balkan, Preethi Atluri, Dieter Saur, Barbara Seidler, Nicholas Tsinoremas, Darcy DiFede, Joshua M Hare
Microgravity-induced alterations in the autonomic nervous system (ANS) contribute to derangements in both the mechanical and electrophysiologic function of the cardiovascular system, leading to severe symptoms in humans following space travel. Because the ANS forms embryonically from neural crest progenitors (NCs), we hypothesized that microgravity can impair NC derived cardiac structures. Accordingly, we conducted in vitro simulated microgravity experiments employing NC genetic lineage-tracing in mice with cKitCreERT2/+, Isl1nLacZ and Wnt1-Cre reporter alleles...
January 16, 2018: Stem Cells and Development
https://www.readbyqxmd.com/read/29327060/optical-coherence-tomography-analysis-of-the-optic-nerve-head-and-surrounding-structures-in-long-duration-international-space-station-astronauts
#5
Nimesh Patel, Anastas Pass, Sara Mason, Charles R Gibson, Christian Otto
Importance: After long-duration spaceflight, morphological changes in the optic nerve head (ONH) and surrounding tissues have been reported. Objective: To develop methods to quantify ONH and surrounding tissue changes using preflight and postflight optical coherence tomographic scans of the ONH region. Design, Setting, and Participants: Two separate analyses were done on retrospective data, with the first comparing a preflight group with a control group, followed by preflight to postflight analysis...
January 11, 2018: JAMA Ophthalmology
https://www.readbyqxmd.com/read/29320953/spaceflight-activates-protein-kinase-c-alpha-signaling-and-modifies-the-developmental-stage-of-human-neonatal-cardiovascular-progenitor-cells
#6
Jonathan Baio, Aida F Martinez, Leonard L Bailey, Nahidh Hasaniya, Michael Pecaut, Mary Kearns-Jonker
Spaceflight impacts cardiovascular function in astronauts; however, its impact on cardiac development and the stem cells that form the basis for cardiac repair is unknown. Accordingly, further research is needed to uncover the potential relevance of such changes to human health. Using simulated microgravity (SMG) generated via two-dimensional clinorotation and culture aboard the International Space Station (ISS), we assessed the effects of mechanical unloading on human neonatal cardiovascular progenitor cell (CPC) developmental properties and signaling...
January 10, 2018: Stem Cells and Development
https://www.readbyqxmd.com/read/29317681/the-effect-of-gravity-on-flame-spread-over-pmma-cylinders
#7
Shmuel Link, Xinyan Huang, Carlos Fernandez-Pello, Sandra Olson, Paul Ferkul
Fire safety is a concern in space travel, particularly with the current plans of increasing the length of the manned space missions, and of using spacecraft atmospheres different than in Earth, such as microgravity, low-velocity gas flow, low pressure and elevated oxygen concentration. In this work, the spread of flame over a thermoplastic polymer, polymethyl methacrylate (PMMA), was conducted in the International Space Station and on Earth. The tests consisted of determining the opposed flame spread rate over PMMA cylinders under low-flow velocities ranging from 0...
January 9, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29307754/physical-constraints-in-cell-fate-specification-a-case-in-point-microgravity-and-phenotypes-differentiation
#8
REVIEW
Maria Grazia Masiello, Roberto Verna, Alessandra Cucina, Mariano Bizzarri
Data obtained by studying mammalian cells in absence of gravity strongly support the notion that cell fate specification cannot be understood according to the current molecular model. A paradigmatic case in point is provided by studying cell populations growing in absence of gravity. When the physical constraint (gravity) is 'experimentally removed', cells spontaneously allocate into two morphologically different phenotypes. Such phenomenon is likely enacted by the intrinsic stochasticity, which, in turn, is successively 'canalized' by a specific gene regulatory network...
January 4, 2018: Progress in Biophysics and Molecular Biology
https://www.readbyqxmd.com/read/29298650/potential-application-of-centrifuges-to-protect-the-cns-in-space-and-on-earth
#9
Yoshiki Takamatsu, Gilbert Ho, Yuki Shimizu, Shuei Sugama, Takato Takenouchi, Masaaki Waragai, Jianshe Wei, Makoto Hashimoto
BACKGROUND: Centrifuges are the principal means of generating physiological hypergravity and have been used for many medical purposes, including the therapy of psychiatric diseases and evaluation of vestibular system in the pilots. In particular, modern centrifuges have evolved into mechanically sophisticated precision instruments compared to primitive ones in old times, indicating that centrifuges might possess great potential in modern medicine. Indeed, studies are in progress to apply centrifuges to musculoskeletal degenerative diseases, such as osteoporosis and sarcopenia...
December 29, 2017: Current Alzheimer Research
https://www.readbyqxmd.com/read/29297120/expression-of-focal-adhesion-genes-in-mesenchymal-stem-cells-under-simulated-microgravity
#10
A Yu Ratushnyy, L B Buravkova
The expression of 84 focal adhesion genes of multipotent mesenchymal stromal cells (MMSCs) after 96-h microgravity simulation at 3D clinorotation was studied. The upregulation of ITGA6, ITGA7, BCAR1, GRB2, CAV1, and DIAPH1 and the downregulation of ITGA11, ITGAV, ITGB1, PTEN, PTK2 (FAK), ARHGAP5, DOCK1, ROCK2, and AKT3 was found. These changes at the transcriptional level may be a cause of the reduction of the osteogenic potential of MMSCs and their ability to migration and adhesion in microgravity.
November 2017: Doklady. Biochemistry and Biophysics
https://www.readbyqxmd.com/read/29286875/growth-and-cortical-microtubule-dynamics-in-shoot-organs-under-microgravity-and-hypergravity-conditions
#11
Kouichi Soga, Kazuyuki Wakabayashi, Takayuki Hoson
The body shape of plants varied in proportion to the logarithm of the magnitude of gravity in the range from microgravity to hypergravity to resist the gravitational force. Here we discuss the roles of cortical microtubule and 65 kDa microtubule-associated protein-1 (MAP65-1) in gravity-induced modification of growth anisotropy. Microgravity stimulated elongation growth and suppressed lateral expansion in shoot organs, such as hypocotyls and epicotyls. On the other hand, hypergravity inhibited elongation growth and promoted lateral expansion in shoot organs...
December 29, 2017: Plant Signaling & Behavior
https://www.readbyqxmd.com/read/29286463/in-vitro-growth-of-mouse-preantral-follicles-under-simulated-microgravity
#12
Shen Zhang, Yonggen Wu, Yimin Weng, Zhihui Xu, Wenmin Chen, Dahan Zheng, Wei Lin, Jun Liu, Ying Zhou
14 day-old mouse ovarian tissue and preantral follicles isolated from same-aged mice were incubated in a simulated microgravity culture system. We quantitatively assessed follicle survival, measured follicle and oocyte diameters, and examined ultrastructure of the oocytes produced from the system. We observed decreased follicle survival, downregulation of expressions of proliferating cell nuclear antigen and growth differentiation factor 9, as indicators for the development of granulosa cells and oocytes, respectively, and oocyte ultrastructural abnormalities under the simulated microgravity condition...
December 17, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/29276139/ultrasound-monitoring-of-jugular-venous-pulse-during-space-missions-proof-of-concept
#13
Paolo Zamboni, Francesco Sisini, Erica Menegatti, Angelo Taibi, Giacomo Gadda, Valentina Tavoni, Anna Maria Malagoni, Mirko Tessari, Sergio Gianesini, Mauro Gambaccini
The jugular venous pulse (JVP) is one of the main parameters of cardiac function and is used by cardiologists in diagnosing heart failure. Its waveform comprises three positive waves (a, c and v) and two negative waves (x and y). Recently, it was found that JVP can be extrapolated from an ultrasound (US) video recording of the internal jugular vein (IJV), suggesting its application in space missions, on which US scanners are already widely used. To date, the feasibility of assessing JVP in microgravity (microG) has not been investigated...
December 21, 2017: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/29233246/intraocular-lens-use-in-an-astronaut-during-long-duration-spaceflight
#14
Thomas H Mader, C Robert Gibson, Josef F Schmid, William Lipsky, Ashot E Sargsyan, Kathleen Garcia, Jeffrey N Williams
BACKGROUND: The purpose of this paper is to report the first use of an intraocular lens (IOL) in an astronaut during long duration spaceflight (LDSF). An astronaut developed a unilateral cataract and underwent phacoemulsification with insertion of an acrylic IOL. Approximately 15 mo later he flew on a Soyuz spacecraft to the International Space Station (ISS), where he successfully completed a 6-mo mission. CASE REPORT: Ocular examination, including ultrasound (US), was performed before, during, and after his mission and he was questioned regarding visual changes during each portion of his flight...
January 1, 2018: Aerospace Medicine and Human Performance
https://www.readbyqxmd.com/read/29233242/preflight-in-flight-and-postflight-imaging-of-the-cervical-and-lumbar-spine-in-astronauts
#15
Michael F Harrison, Kathleen M Garcia, Ashot E Sargsyan, Douglas Ebert, Roy F Riascos-Castaneda, Scott A Dulchavsky
BACKGROUND: Back pain is a common complaint during spaceflight that is commonly attributed to intervertebral disc swelling in microgravity. Ultrasound (US) represents the only imaging modality on the International Space Station (ISS) to assess its etiology. The present study investigated: 1) The agreement and correlation of spinal US assessments as compared to results of pre- and postflight MRI studies; and 2) the trend in intervertebral disc characteristics over the course of spaceflight to ISS...
January 1, 2018: Aerospace Medicine and Human Performance
https://www.readbyqxmd.com/read/29228060/model-of-hindlimb-unloading-in-adult-female-rats-characterizing-bone-physicochemical-microstructural-and-biomechanical-properties
#16
Melise Jacon Peres-Ueno, Camila Tami Stringhetta-Garcia, Robson Chacon Castoldi, Guilherme Akio Tamura Ozaki, Antônio Hernandes Chaves-Neto, Rita Cássia Menegati Dornelles, Mário Jefferson Quirino Louzada
Prolonged bedrest and microgravity induce alterations to bone, leading to bone fragility and compromising the quality of life. In this study, we characterized the physicochemical changes, microstructure, and biomechanics of the femurs of female adult rats in response to hindlimb unloading for 21 days. Twenty 6-month-old Wistar female rats were distributed into control (CON) and hindlimb unloading (HLU) groups. Analysis the in vivo bone mineral density (BMD) by dual energy x-ray absorptiometry (DXA) from the femurs was performed at the beginning and end of the experiment; plasma levels of calcium, phosphorus, and alkaline phosphatase, tartrate-resistant acid phosphatase activity, assessed by spectrophotometry, and estradiol, measured by enzyme-linked immunosorbent assay, was performed after the experiment...
2017: PloS One
https://www.readbyqxmd.com/read/29207065/estrogen-inhibits-the-overgrowth-of-escherichia%C3%A2-coli-in-the-rat-intestine-under-simulated-microgravity
#17
Yongtao Yang, Changmin Qu, Shuwen Liang, Gang Wang, Haolun Han, Na Chen, Xiaoying Wang, Zhiwen Luo, Changqing Zhong, Yan Chen, Lianyong Li, Wei Wu
Microgravity can affect many aspects of intestinal homeostasis, leading to an increased risk of colitis. Estrogen, the most frequently affected hormone when under simulated microgravity, regulates the permeability of the colonic mucosa barrier. The associations between alterations in intestinal microbiota and increased susceptibility under microgravity have not been thoroughly elucidated. The aim of the present study was to evaluate the changes in intestinal microbiota under simulated microgravity and to investigate the protective effect of estrogen against those changes...
November 20, 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/29198315/mimicking-the-effects-of-spaceflight-on-bone-combined-effects-of-disuse-and-chronic-low-dose-rate-radiation-exposure-on-bone-mass-in-mice
#18
Kanglun Yu, Alison H Doherty, Paula C Genik, Sara E Gookin, Danielle M Roteliuk, Samantha J Wojda, Zhi-Sheng Jiang, Meghan E McGee-Lawrence, Michael M Weil, Seth W Donahue
During spaceflight, crewmembers are subjected to biomechanical and biological challenges including microgravity and radiation. In the skeleton, spaceflight leads to bone loss, increasing the risk of fracture. Studies utilizing hindlimb suspension (HLS) as a ground-based model of spaceflight often neglect the concomitant effects of radiation exposure, and even when radiation is accounted for, it is often delivered at a high-dose rate over a very short period of time, which does not faithfully mimic spaceflight conditions...
November 2017: Life Sciences in Space Research
https://www.readbyqxmd.com/read/29198314/t-cell-resistance-to-activation-by-dendritic-cells-requires-long-term-culture-in-simulated-microgravity
#19
Jillian H Bradley, Rachel Stein, Brad Randolph, Emily Molina, Jennifer P Arnold, Randal K Gregg
Immune impairment mediated by microgravity threatens the success of space exploration requiring long-duration spaceflight. The cells of most concern, T lymphocytes, coordinate the host response against microbial and cancerous challenges leading to elimination and long-term protection. T cells are activated upon recognition of specific microbial peptides bound on the surface of antigen presenting cells, such as dendritic cells (DC). Subsequently, this engagement results in T cell proliferation and differentiation into effector T cells driven by autocrine interleukin-2 (IL-2) and other cytokines...
November 2017: Life Sciences in Space Research
https://www.readbyqxmd.com/read/29198309/effects-of-simulated-microgravity-on-gene-expression-and-biological-phenotypes-of-a-single-generation-caenorhabditis-elegans-cultured-on-2-different-media
#20
Ling Fei Tee, Hui-Min Neoh, Sue Mian Then, Nor Azian Murad, Mohd Fairos Asillam, Mohd Helmy Hashim, Sheila Nathan, Rahman Jamal
Studies of multigenerational Caenorhabditis elegans exposed to long-term spaceflight have revealed expression changes of genes involved in longevity, DNA repair, and locomotion. However, results from spaceflight experiments are difficult to reproduce as space missions are costly and opportunities are rather limited for researchers. In addition, multigenerational cultures of C. elegans used in previous studies contribute to mixture of gene expression profiles from both larvae and adult worms, which were recently reported to be different...
November 2017: Life Sciences in Space Research
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