Validity of microgravity simulation models on earth

DEFF Research Database (Denmark)

Regnard, J; Heer, M; Drummer, C

2001-01-01

Many studies have used water immersion and head-down bed rest as experimental models to simulate responses to microgravity. However, some data collected during space missions are at variance or in contrast with observations collected from experimental models. These discrepancies could reflect...... incomplete knowledge of the characteristics inherent to each model. During water immersion, the hydrostatic pressure lowers the peripheral vascular capacity and causes increased thoracic blood volume and high vascular perfusion. In turn, these changes lead to high urinary flow, low vasomotor tone, and a high...

The SOS and RpoS Regulons Contribute to Bacterial Cell Robustness to Genotoxic Stress by Synergistically Regulating DNA Polymerase Pol II.

Science.gov (United States)

Dapa, Tanja; Fleurier, Sébastien; Bredeche, Marie-Florence; Matic, Ivan

2017-07-01

Mitomycin C (MMC) is a genotoxic agent that induces DNA cross-links, DNA alkylation, and the production of reactive oxygen species (ROS). MMC induces the SOS response and RpoS regulons in Escherichia coli SOS-encoded functions are required for DNA repair, whereas the RpoS regulon is typically induced by metabolic stresses that slow growth. Thus, induction of the RpoS regulon by MMC may be coincidental, because DNA damage slows growth; alternatively, the RpoS regulon may be an adaptive response contributing to cell survival. In this study, we show that the RpoS regulon is primarily induced by MMC-induced ROS production. We also show that RpoS regulon induction is required for the survival of MMC-treated growing cells. The major contributor to RpoS-dependent resistance to MMC treatment is DNA polymerase Pol II, which is encoded by the polB gene belonging to the SOS regulon. The observation that polB gene expression is controlled by the two major stress response regulons that are required to maximize survival and fitness further emphasizes the key role of this DNA polymerase as an important factor in genome stability. Copyright © 2017 by the Genetics Society of America.

Effect of modeled microgravity on radiation-induced adaptive response of root growth in Arabidopsis thaliana

International Nuclear Information System (INIS)

Deng, Chenguang; Wang, Ting; Wu, Jingjing; Xu, Wei; Li, Huasheng; Liu, Min

2017-01-01

Highlights: • The radio-adaptive response (RAR) of A. thaliana root growth is modulated in microgravity. • The DNA damage repairs in RAR are regulated by microgravity. • The phytohormone auxin plays a regulatory role in the modulation of microgravity on RAR of root growth. - Abstract: Space particles have an inevitable impact on organisms during space missions; radio-adaptive response (RAR) is a critical radiation effect due to both low-dose background and sudden high-dose radiation exposure during solar storms. Although it is relevant to consider RAR within the context of microgravity, another major space environmental factor, there is no existing evidence as to its effects on RAR. In the present study, we established an experimental method for detecting the effects of gamma-irradiation on the primary root growth of Arabidopsis thaliana, in which RAR of root growth was significantly induced by several dose combinations. Microgravity was simulated using a two-dimensional rotation clinostat. It was shown that RAR of root growth was significantly inhibited under the modeled microgravity condition, and was absent in pgm-1 plants that had impaired gravity sensing in root tips. These results suggest that RAR could be modulated in microgravity. Time course analysis showed that microgravity affected either the development of radio-resistance induced by priming irradiation, or the responses of plants to challenging irradiation. After treatment with the modeled microgravity, attenuation in priming irradiation-induced expressions of DNA repair genes (AtKu70 and AtRAD54), and reduced DNA repair efficiency in response to challenging irradiation were observed. In plant roots, the polar transportation of the phytohormone auxin is regulated by gravity, and treatment with an exogenous auxin (indole-3-acetic acid) prevented the induction of RAR of root growth, suggesting that auxin might play a regulatory role in the interaction between microgravity and RAR of root growth.

Effect of modeled microgravity on radiation-induced adaptive response of root growth in Arabidopsis thaliana

Energy Technology Data Exchange (ETDEWEB)

Deng, Chenguang [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China); Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province (China); Institute of Technical Biology and Agriculture Engineering, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Wang, Ting [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China); Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province (China); Institute of Technical Biology and Agriculture Engineering, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei 230031 (China); Wu, Jingjing [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China); Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province (China); Institute of Technical Biology and Agriculture Engineering, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Xu, Wei [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China); Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province (China); Institute of Technical Biology and Agriculture Engineering, Chinese Academy of Sciences, 350 Shushanhu Road, Hefei 230031 (China); Li, Huasheng; Liu, Min [China Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086 (China); and others

2017-02-15

Highlights: • The radio-adaptive response (RAR) of A. thaliana root growth is modulated in microgravity. • The DNA damage repairs in RAR are regulated by microgravity. • The phytohormone auxin plays a regulatory role in the modulation of microgravity on RAR of root growth. - Abstract: Space particles have an inevitable impact on organisms during space missions; radio-adaptive response (RAR) is a critical radiation effect due to both low-dose background and sudden high-dose radiation exposure during solar storms. Although it is relevant to consider RAR within the context of microgravity, another major space environmental factor, there is no existing evidence as to its effects on RAR. In the present study, we established an experimental method for detecting the effects of gamma-irradiation on the primary root growth of Arabidopsis thaliana, in which RAR of root growth was significantly induced by several dose combinations. Microgravity was simulated using a two-dimensional rotation clinostat. It was shown that RAR of root growth was significantly inhibited under the modeled microgravity condition, and was absent in pgm-1 plants that had impaired gravity sensing in root tips. These results suggest that RAR could be modulated in microgravity. Time course analysis showed that microgravity affected either the development of radio-resistance induced by priming irradiation, or the responses of plants to challenging irradiation. After treatment with the modeled microgravity, attenuation in priming irradiation-induced expressions of DNA repair genes (AtKu70 and AtRAD54), and reduced DNA repair efficiency in response to challenging irradiation were observed. In plant roots, the polar transportation of the phytohormone auxin is regulated by gravity, and treatment with an exogenous auxin (indole-3-acetic acid) prevented the induction of RAR of root growth, suggesting that auxin might play a regulatory role in the interaction between microgravity and RAR of root growth.

Finite Element Modeling of the Posterior Eye in Microgravity

Science.gov (United States)

Feola, Andrew; Raykin, Julia; Mulugeta, Lealem; Gleason, Rudolph; Myers, Jerry G.; Nelson, Emily S.; Samuels, Brian; Ethier, C. Ross

2015-01-01

Microgravity experienced during spaceflight affects astronauts in various ways, including weakened muscles and loss of bone density. Recently, visual impairment and intracranial pressure (VIIP) syndrome has become a major concern for space missions lasting longer than 30 days. Astronauts suffering from VIIP syndrome have changes in ocular anatomical and visual impairment that persist after returning to earth. It is hypothesized that a cephalad fluid shift in microgravity may increase the intracranial pressure (ICP), which leads to an altered biomechanical environment of the posterior globe and optic nerve sheath (ONS).Currently, there is a lack of knowledge of how elevated ICP may lead to vision impairment and connective tissue changes in VIIP. Our goal was to develop a finite element model to simulate the acute effects of elevated ICP on the posterior eye and optic nerve sheath. We used a finite element (FE) analysis approach to understand the response of the lamina cribrosa and optic nerve to the elevations in ICP thought to occur in microgravity and to identify which tissue components have the greatest impact on strain experienced by optic nerve head tissues.

Involvement and necessity of the Cpx regulon in the event of aberrant β-barrel outer membrane protein assembly

Science.gov (United States)

Gerken, Henri; Leiser, Owen P.; Bennion, Drew; Misra, Rajeev

2010-01-01

Summary The Cpx and σE regulons help maintain outer membrane integrity; the Cpx pathway monitors the biogenesis of cell surface structures, such as pili, while the σE pathway monitors the biogenesis of β-barrel outer membrane proteins (OMPs). In this study we revealed the importance of the Cpx regulon in the event of β-barrel OMP mis-assembly, by utilizing mutants expressing either a defective β-barrel OMP assembly machinery (Bam) or assembly defective β-barrel OMPs. Analysis of specific mRNAs showed that ΔcpxR bam double mutants failed to induce degP expression beyond the wild type level, despite activation of the σE pathway. The synthetic conditional lethal phenotype of ΔcpxR in mutant Bam or β-barrel OMP backgrounds was reversed by wild type DegP expressed from a heterologous plasmid promoter. Consistent with the involvement of the Cpx regulon in the event of aberrant β-barrel OMP assembly, the expression of cpxP, the archetypal member of the cpx regulon, was upregulated in defective Bam backgrounds or in cells expressing a single assembly-defective β-barrel OMP species. Together, these results showed that both the Cpx and σE regulons are required to reduce envelope stress caused by aberrant β-barrel OMP assembly, with the Cpx regulon principally contributing by controlling degP expression. PMID:20487295

Identification of self-consistent modulons from bacterial microarray expression data with the help of structured regulon gene sets

KAUST Repository

Permina, Elizaveta A.; Medvedeva, Yulia; Baeck, Pia M.; Hegde, Shubhada R.; Mande, Shekhar C.; Makeev, Vsevolod J.

2013-01-01

interactions helps to evaluate parameters for regulatory subnetwork inference. We suggest a procedure for modulon construction where a seed regulon is iteratively updated with genes having expression patterns similar to those for regulon member genes. A set

Modeling of two-phase flow in membranes and porous media in microgravity as applied to plant irrigation in space

Science.gov (United States)

Scovazzo, P.; Illangasekare, T. H.; Hoehn, A.; Todd, P.

2001-01-01

In traditional applications in soil physics it is convention to scale porous media properties, such as hydraulic conductivity, soil water diffusivity, and capillary head, with the gravitational acceleration. In addition, the Richards equation for water flux in partially saturated porous media also contains a gravity term. With the plans to develop plant habitats in space, such as in the International Space Station, it becomes necessary to evaluate these properties and this equation under conditions of microgravitational acceleration. This article develops models for microgravity steady state two-phase flow, as found in irrigation systems, that addresses critical design issues. Conventional dimensionless groups in two-phase mathematical models are scaled with gravity, which must be assigned a value of zero for microgravity modeling. The use of these conventional solutions in microgravity, therefore, is not possible. This article therefore introduces new dimensionless groups for two-phase models. The microgravity models introduced here determined that in addition to porous media properties, important design factors for microgravity systems include applied water potential and the ratio of inner to outer radii for cylindrical and spherical porous media systems.

Deep sequencing whole transcriptome exploration of the σE regulon in Neisseria meningitidis.

Directory of Open Access Journals (Sweden)

Robert Antonius Gerhardus Huis in 't Veld

Full Text Available Bacteria live in an ever-changing environment and must alter protein expression promptly to adapt to these changes and survive. Specific response genes that are regulated by a subset of alternative σ(70-like transcription factors have evolved in order to respond to this changing environment. Recently, we have described the existence of a σ(E regulon including the anti-σ-factor MseR in the obligate human bacterial pathogen Neisseria meningitidis. To unravel the complete σ(E regulon in N. meningitidis, we sequenced total RNA transcriptional content of wild type meningococci and compared it with that of mseR mutant cells (ΔmseR in which σ(E is highly expressed. Eleven coding genes and one non-coding gene were found to be differentially expressed between H44/76 wildtype and H44/76ΔmseR cells. Five of the 6 genes of the σ(E operon, msrA/msrB, and the gene encoding a pepSY-associated TM helix family protein showed enhanced transcription, whilst aniA encoding a nitrite reductase and nspA encoding the vaccine candidate Neisserial surface protein A showed decreased transcription. Analysis of differential expression in IGRs showed enhanced transcription of a non-coding RNA molecule, identifying a σ(E dependent small non-coding RNA. Together this constitutes the first complete exploration of an alternative σ-factor regulon in N. meningitidis. The results direct to a relatively small regulon indicative for a strictly defined response consistent with a relatively stable niche, the human throat, where N. meningitidis resides.

Model of ASTM Flammability Test in Microgravity: Iron Rods

Science.gov (United States)

Steinberg, Theodore A; Stoltzfus, Joel M.; Fries, Joseph (Technical Monitor)

2000-01-01

There is extensive qualitative results from burning metallic materials in a NASA/ASTM flammability test system in normal gravity. However, this data was shown to be inconclusive for applications involving oxygen-enriched atmospheres under microgravity conditions by conducting tests using the 2.2-second Lewis Research Center (LeRC) Drop Tower. Data from neither type of test has been reduced to fundamental kinetic and dynamic systems parameters. This paper reports the initial model analysis for burning iron rods under microgravity conditions using data obtained at the LERC tower and modeling the burning system after ignition. Under the conditions of the test the burning mass regresses up the rod to be detached upon deceleration at the end of the drop. The model describes the burning system as a semi-batch, well-mixed reactor with product accumulation only. This model is consistent with the 2.0-second duration of the test. Transient temperature and pressure measurements are made on the chamber volume. The rod solid-liquid interface melting rate is obtained from film records. The model consists of a set of 17 non-linear, first-order differential equations which are solved using MATLAB. This analysis confirms that a first-order rate, in oxygen concentration, is consistent for the iron-oxygen kinetic reaction. An apparent activation energy of 246.8 kJ/mol is consistent for this model.

Effect of modeled microgravity on UV-C-induced interplant communication of Arabidopsis thaliana.

Science.gov (United States)

Wang, Ting; Xu, Wei; Li, Huasheng; Deng, Chenguang; Zhao, Hui; Wu, Yuejin; Liu, Min; Wu, Lijun; Lu, Jinying; Bian, Po

2017-12-01

Controlled ecological life support systems (CELSS) will be an important feature of long-duration space missions of which higher plants are one of the indispensable components. Because of its pivotal role in enabling plants to cope with environmental stress, interplant communication might have important implications for the ecological stability of such CELSS. However, the manifestations of interplant communication in microgravity conditions have yet to be fully elucidated. To address this, a well-established Arabidopsis thaliana co-culture experimental system, in which UV-C-induced airborne interplant communication is evaluated by the alleviation of transcriptional gene silencing (TGS) in bystander plants, was placed in microgravity modeled by a two-dimensional rotating clinostat. Compared with plants under normal gravity, TGS alleviation in bystander plants was inhibited in microgravity. Moreover, TGS alleviation was also prevented when plants of the pgm-1 line, which are impaired in gravity sensing, were used in either the UV-C-irradiated or bystander group. In addition to the specific TGS-loci, interplant communication-shaped genome-wide DNA methylation in bystander plants was altered under microgravity conditions. These results indicate that interplant communications might be modified in microgravity. Time course analysis showed that microgravity interfered with both the production of communicative signals in UV-C-irradiated plants and the induction of epigenetic responses in bystander plants. This was further confirmed by the experimental finding that microgravity also prevented the response of bystander plants to exogenous methyl jasmonate (JA) and methyl salicylate (SA), two well-known airborne signaling molecules, and down-regulated JA and SA biosynthesis in UV-C-irradiated plants. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparative genomics of metabolic capacities of regulons controlled by cis-regulatory RNA motifs in bacteria.

Science.gov (United States)

Sun, Eric I; Leyn, Semen A; Kazanov, Marat D; Saier, Milton H; Novichkov, Pavel S; Rodionov, Dmitry A

2013-09-02

In silico comparative genomics approaches have been efficiently used for functional prediction and reconstruction of metabolic and regulatory networks. Riboswitches are metabolite-sensing structures often found in bacterial mRNA leaders controlling gene expression on transcriptional or translational levels.An increasing number of riboswitches and other cis-regulatory RNAs have been recently classified into numerous RNA families in the Rfam database. High conservation of these RNA motifs provides a unique advantage for their genomic identification and comparative analysis. A comparative genomics approach implemented in the RegPredict tool was used for reconstruction and functional annotation of regulons controlled by RNAs from 43 Rfam families in diverse taxonomic groups of Bacteria. The inferred regulons include ~5200 cis-regulatory RNAs and more than 12000 target genes in 255 microbial genomes. All predicted RNA-regulated genes were classified into specific and overall functional categories. Analysis of taxonomic distribution of these categories allowed us to establish major functional preferences for each analyzed cis-regulatory RNA motif family. Overall, most RNA motif regulons showed predictable functional content in accordance with their experimentally established effector ligands. Our results suggest that some RNA motifs (including thiamin pyrophosphate and cobalamin riboswitches that control the cofactor metabolism) are widespread and likely originated from the last common ancestor of all bacteria. However, many more analyzed RNA motifs are restricted to a narrow taxonomic group of bacteria and likely represent more recent evolutionary innovations. The reconstructed regulatory networks for major known RNA motifs substantially expand the existing knowledge of transcriptional regulation in bacteria. The inferred regulons can be used for genetic experiments, functional annotations of genes, metabolic reconstruction and evolutionary analysis. The obtained genome

The Streptococcus sanguinis Competence Regulon Is Not Required for Infective Endocarditis Virulence in a Rabbit Model

OpenAIRE

Callahan, Jill E.; Munro, Cindy L.; Kitten, Todd

2011-01-01

Streptococcus sanguinis is an important component of dental plaque and a leading cause of infective endocarditis. Genetic competence in S. sanguinis requires a quorum sensing system encoded by the early comCDE genes, as well as late genes controlled by the alternative sigma factor, ComX. Previous studies of Streptococcus pneumoniae and Streptococcus mutans have identified functions for the >100-gene com regulon in addition to DNA uptake, including virulence. We investigated this possibility i...

Transcription profiling of S. cerevisiae cultures grown under low shear-modeled microgravity

Data.gov (United States)

National Aeronautics and Space Administration — The goal of this study was to assess whether low shear-modeled microgravity (LSMMG) effects yeast ,genomic expression patterns using the powerful tool of whole...

Developing Physiologic Models for Emergency Medical Procedures Under Microgravity

Science.gov (United States)

Parker, Nigel; O'Quinn, Veronica

2012-01-01

Several technological enhancements have been made to METI's commercial Emergency Care Simulator (ECS) with regard to how microgravity affects human physiology. The ECS uses both a software-only lung simulation, and an integrated mannequin lung that uses a physical lung bag for creating chest excursions, and a digital simulation of lung mechanics and gas exchange. METI s patient simulators incorporate models of human physiology that simulate lung and chest wall mechanics, as well as pulmonary gas exchange. Microgravity affects how O2 and CO2 are exchanged in the lungs. Procedures were also developed to take into affect the Glasgow Coma Scale for determining levels of consciousness by varying the ECS eye-blinking function to partially indicate the level of consciousness of the patient. In addition, the ECS was modified to provide various levels of pulses from weak and thready to hyper-dynamic to assist in assessing patient conditions from the femoral, carotid, brachial, and pedal pulse locations.

Analysis of the Pho regulon in Streptomyces tsukubaensis.

Science.gov (United States)

Ordóñez-Robles, María; Santos-Beneit, Fernando; Rodríguez-García, Antonio; Martín, Juan F

2017-12-01

Phosphate regulation of antibiotic biosynthesis in Streptomyces has been studied due to the importance of this genus as a source of secondary metabolites with biological activity. Streptomyces tsukubaensis is the main producer of tacrolimus (or FK506), an immunosuppressant macrolide that generates important benefits for the pharmaceutical market. However, the production of tacrolimus is under a negative control by phosphate and, therefore, is important to know the molecular mechanism of this regulation. Despite its important role, there are no reports about the Pho regulon in S. tsukubaensis. In this work we combined transcriptional studies on the response to phosphate starvation with the search for PHO boxes in the whole genome sequence of S. tsukubaensis. As a result, we identified a set of genes responding to phosphate starvation and containing PHO boxes that include common Pho regulon members but also new species-specific candidates. In addition, we demonstrate for the first time the functional activity of PhoP from S. tsukubaensis through complementation studies in a Streptomyces coelicolor ΔphoP strain. For this purpose, we developed an anhydrotetracycline inducible system that can be applied to the controlled expression of target genes. Copyright © 2017 Elsevier GmbH. All rights reserved.

Mathematical Modeling of Wastewater Oxidation under Microgravity Conditions

OpenAIRE

Boyun Guo; Donald W. Holder; David S. Schechter

2005-01-01

Volatile removal assembly (VRA) is a module installed in the International Space Station for removing contaminants (volatile organics) in the wastewater produced by the crew. The VRA contains a slim pack bed reactor to perform catalyst oxidation of the wastewater at elevated pressure and temperature under microgravity conditions. Optimal design of the reactor requires a thorough understanding about how the reactor performs under microgravity conditions. The objective of this study was to theo...

Development of microgravity, full body functional reach envelope using 3-D computer graphic models and virtual reality technology

Science.gov (United States)

Lindsey, Patricia F.

1994-01-01

In microgravity conditions mobility is greatly enhanced and body stability is difficult to achieve. Because of these difficulties, optimum placement and accessibility of objects and controls can be critical to required tasks on board shuttle flights or on the proposed space station. Anthropometric measurement of the maximum reach of occupants of a microgravity environment provide knowledge about maximum functional placement for tasking situations. Calculations for a full body, functional reach envelope for microgravity environments are imperative. To this end, three dimensional computer modeled human figures, providing a method of anthropometric measurement, were used to locate the data points that define the full body, functional reach envelope. Virtual reality technology was utilized to enable an occupant of the microgravity environment to experience movement within the reach envelope while immersed in a simulated microgravity environment.

Increased Arginine and Ornithine Flux in Islets of Langerhans Cultured in a Microgravity Model System

Science.gov (United States)

Tobin, B. W.; Sams, C. F.; Smith, S. M.

2000-01-01

Microgravity is associated with alterations in protein metabolism of both muscle and bone. That pancreas-derived insulin is essential to the normal maintenance of body protein balance is well known. The importance of altered endocrine pancreas function in microgravity is not yet established. We proposed to examine the influence of a microgravity model system, the High Aspect Ratio Vessel (HARV) upon islets of Langerhans from Wistar Furth rats. Islets were cultured in the HARV for 48 hr in Medium-199 and contrasted to static control islets (PLATE). Nitrogenous compounds elaborated into the media (micromoles/ml) were analyzed at 0 and 48 hr of culture and compared to PLATE with a 2-way ANOVA (HARV vs Hour).

Microgravity Disturbance Predictions in the Combustion Integrated Rack

Science.gov (United States)

Just, M.; Grodsinsky, Carlos M.

2002-01-01

This paper will focus on the approach used to characterize microgravity disturbances in the Combustion Integrated Rack (CIR), currently scheduled for launch to the International Space Station (ISS) in 2005. Microgravity experiments contained within the CIR are extremely sensitive to vibratory and transient disturbances originating on-board and off-board the rack. Therefore, several techniques are implemented to isolate the critical science locations from external vibration. A combined testing and analysis approach is utilized to predict the resulting microgravity levels at the critical science location. The major topics to be addressed are: 1) CIR Vibration Isolation Approaches, 2) Disturbance Sources and Characterization, 3) Microgravity Predictive Modeling, 4) Science Microgravity Requirements, 6) Microgravity Control, and 7) On-Orbit Disturbance Measurement. The CIR is using the Passive Rack Isolation System (PaRIS) to isolate the rack from offboard rack disturbances. By utilizing this system, CIR is connected to the U.S. Lab module structure by either 13 or 14 umbilical lines and 8 spring / damper isolators. Some on-board CIR disturbers are locally isolated by grommets or wire ropes. CIR's environmental and science on board support equipment such as air circulation fans, pumps, water flow, air flow, solenoid valves, and computer hard drives cause disturbances within the rack. These disturbers along with the rack structure must be characterized to predict whether the on-orbit vibration levels during experimentation exceed the specified science microgravity vibration level requirements. Both vibratory and transient disturbance conditions are addressed. Disturbance levels/analytical inputs are obtained for each individual disturber in a "free floating" condition in the Glenn Research Center (GRC) Microgravity Emissions Lab (MEL). Flight spare hardware is tested on an Orbital Replacement Unit (ORU) basis. Based on test and analysis, maximum disturbance level

Modelled microgravity alters the Na+, K+-ATPase activity in rat heart homogenates

Science.gov (United States)

Peana, Alessandra T.; Pippia, Proto; Paci, Silvia; Tognacini, Christina; Assaretti, Anna Rita; Meloni, Antonietta M.; Galleri, Grazia; Bernardini, Federico

2005-08-01

This study was aimed at establishing whether modeled microgravity conditions, created in a three-dimensional clinostat (Random Positioning Machine, RPM), influence the membrane-associated Na+, K+- and Mg2+- ATPase activities in heart homogenates from rats (ex- posed to RPM for 48 hours). The experimental data indicate that modeled low g significantly decreased the total ATPase (p<0.01) and Na+, K+ -ATPase activities (p<0.05) with no change of the Mg2+-ATPase activity, compared to the respective rat control groups (ground). This Na+, K+- pump inhibition could cause a digital- like effect in response to several modifications of many physiological processes even if this inhibition might also be causally related to the physiological environment induced by RPM. The exact mechanism by which total A TPase and Na+, K+ -A TPase activities decrease in response to RPM conditions remains to be established. We cannot rule out that a reduced intracellular ATP production, previously demonstrated in other cellular systems submitted to modeled microgravity conditions, could be responsible for the effects reported here.

Effect of Low Shear Modeled Microgravity (LSMMG) on the Probiotic Lactobacillus Acidophilus ATCC 4356

Science.gov (United States)

Stahl, S.; Voorhies, A.; Lorenzi, H.; Castro-Wallace, S.; Douglas, G.

2016-01-01

The introduction of generally recognized as safe (GRAS) probiotic microbes into the spaceflight food system has the potential for use as a safe, non-invasive, daily countermeasure to crew microbiome and immune dysregulation. However, the microgravity effects on the stress tolerances and genetic expression of probiotic bacteria must be determined to confirm translation of strain benefits and to identify potential for optimization of growth, survival, and strain selection for spaceflight. The work presented here demonstrates the translation of characteristics of a GRAS probiotic bacteria to a microgravity analog environment. Lactobacillus acidophilus ATCC 4356 was grown in the low shear modeled microgravity (LSMMG) orientation and the control orientation in the rotating wall vessel (RWV) to determine the effect of LSMMG on the growth, survival through stress challenge, and gene expression of the strain. No differences were observed between the LSMMG and control grown L. acidophilus, suggesting that the strain will behave similarly in spaceflight and may be expected to confer Earth-based benefits.

Definition of the σ(W) regulon of Bacillus subtilis in the absence of stress.

Science.gov (United States)

Zweers, Jessica C; Nicolas, Pierre; Wiegert, Thomas; van Dijl, Jan Maarten; Denham, Emma L

2012-01-01

Bacteria employ extracytoplasmic function (ECF) sigma factors for their responses to environmental stresses. Despite intensive research, the molecular dissection of ECF sigma factor regulons has remained a major challenge due to overlaps in the ECF sigma factor-regulated genes and the stimuli that activate the different ECF sigma factors. Here we have employed tiling arrays to single out the ECF σ(W) regulon of the Gram-positive bacterium Bacillus subtilis from the overlapping ECF σ(X), σ(Y), and σ(M) regulons. For this purpose, we profiled the transcriptome of a B. subtilis sigW mutant under non-stress conditions to select candidate genes that are strictly σ(W)-regulated. Under these conditions, σ(W) exhibits a basal level of activity. Subsequently, we verified the σ(W)-dependency of candidate genes by comparing their transcript profiles to transcriptome data obtained with the parental B. subtilis strain 168 grown under 104 different conditions, including relevant stress conditions, such as salt shock. In addition, we investigated the transcriptomes of rasP or prsW mutant strains that lack the proteases involved in the degradation of the σ(W) anti-sigma factor RsiW and subsequent activation of the σ(W)-regulon. Taken together, our studies identify 89 genes as being strictly σ(W)-regulated, including several genes for non-coding RNAs. The effects of rasP or prsW mutations on the expression of σ(W)-dependent genes were relatively mild, which implies that σ(W)-dependent transcription under non-stress conditions is not strictly related to RasP and PrsW. Lastly, we show that the pleiotropic phenotype of rasP mutant cells, which have defects in competence development, protein secretion and membrane protein production, is not mirrored in the transcript profile of these cells. This implies that RasP is not only important for transcriptional regulation via σ(W), but that this membrane protease also exerts other important post-transcriptional regulatory

Characterization of the YdeO regulon in Escherichia coli.

Directory of Open Access Journals (Sweden)

Yuki Yamanaka

Full Text Available Enterobacteria are able to survive under stressful conditions within animals, such as acidic conditions in the stomach, bile salts during transfer to the intestine and anaerobic conditions within the intestine. The glutamate-dependent (GAD system plays a major role in acid resistance in Escherichia coli, and expression of the GAD system is controlled by the regulatory cascade consisting of EvgAS > YdeO > GadE. To understand the YdeO regulon in vivo, we used ChIP-chip to interrogate the E. coli genome for candidate YdeO binding sites. All of the seven operons identified by ChIP-chip as being potentially regulated by YdeO were confirmed as being under the direct control of YdeO using RT-qPCR, EMSA, DNaseI-footprinting and reporter assays. Within this YdeO regulon, we identified four stress-response transcription factors, DctR, NhaR, GadE, and GadW and enzymes for anaerobic respiration. Both GadE and GadW are involved in regulation of the GAD system and NhaR is an activator for the sodium/proton antiporter gene. In conjunction with co-transcribed Slp, DctR is involved in protection against metabolic endoproducts under acidic conditions. Taken all together, we suggest that YdeO is a key regulator of E. coli survival in both acidic and anaerobic conditions.

Finite Element Analysis of Osteocytes Mechanosensitivity Under Simulated Microgravity

Science.gov (United States)

Yang, Xiao; Sun, Lian-Wen; Du, Cheng-Fei; Wu, Xin-Tong; Fan, Yu-Bo

2018-04-01

It was found that the mechanosensitivity of osteocytes could be altered under simulated microgravity. However, how the mechanical stimuli as the biomechanical origins cause the bioresponse in osteocytes under microgravity is unclear yet. Computational studies may help us to explore the mechanical deformation changes of osteocytes under microgravity. Here in this paper, we intend to use the computational simulation to investigate the mechanical behavior of osteocytes under simulated microgravity. In order to obtain the shape information of osteocytes, the biological experiment was conducted under simulated microgravity prior to the numerical simulation The cells were rotated by a clinostat for 6 hours or 5 days and fixed, the cytoskeleton and the nucleus were immunofluorescence stained and scanned, and the cell shape and the fluorescent intensity were measured from fluorescent images to get the dimension information of osteocytes The 3D finite element (FE) cell models were then established based on the scanned image stacks. Several components such as the actin cortex, the cytoplasm, the nucleus, the cytoskeleton of F-actin and microtubules were considered in the model. The cell models in both 6 hours and 5 days groups were then imposed by three magnitudes (0.5, 10 and 15 Pa) of simulating fluid shear stress, with cell total displacement and the internal discrete components deformation calculated. The results showed that under the simulated microgravity: (1) the nuclear area and height statistically significantly increased, which made the ratio of membrane-cortex height to nucleus height statistically significantly decreased; (2) the fluid shear stress-induced maximum displacements and average displacements in the whole cell decreased, with the deformation decreasing amplitude was largest when exposed to 1.5Pa of fluid shear stress; (3) the fluid shear stress-induced deformation of cell membrane-cortex and cytoskeleton decreased, while the fluid shear stress

Microgravity Two-Phase Flow Transition

Science.gov (United States)

Parang, M.; Chao, D.

1999-01-01

Two-phase flows under microgravity condition find a large number of important applications in fluid handling and storage, and spacecraft thermal management. Specifically, under microgravity condition heat transfer between heat exchanger surfaces and fluids depend critically on the distribution and interaction between different fluid phases which are often qualitatively different from the gravity-based systems. Heat transfer and flow analysis in two-phase flows under these conditions require a clear understanding of the flow pattern transition and development of appropriate dimensionless scales for its modeling and prediction. The physics of this flow is however very complex and remains poorly understood. This has led to various inadequacies in flow and heat transfer modeling and has made prediction of flow transition difficult in engineering design of efficient thermal and flow systems. In the present study the available published data for flow transition under microgravity condition are considered for mapping. The transition from slug to annular flow and from bubbly to slug flow are mapped using dimensionless variable combination developed in a previous study by the authors. The result indicate that the new maps describe the flow transitions reasonably well over the range of the data available. The transition maps are examined and the results are discussed in relation to the presumed balance of forces and flow dynamics. It is suggested that further evaluation of the proposed flow and transition mapping will require a wider range of microgravity data expected to be made available in future studies.

Numerical Investigation of Microgravity Tank Pressure Rise Due to Boiling

Science.gov (United States)

Hylton, Sonya; Ibrahim, Mounir; Kartuzova, Olga; Kassemi, Mohammad

2015-01-01

The ability to control self-pressurization in cryogenic storage tanks is essential for NASAs long-term space exploration missions. Predictions of the tank pressure rise in Space are needed in order to inform the microgravity design and optimization process. Due to the fact that natural convection is very weak in microgravity, heat leaks into the tank can create superheated regions in the liquid. The superheated regions can instigate microgravity boiling, giving rise to pressure spikes during self-pressurization. In this work, a CFD model is developed to predict the magnitude and duration of the microgravity pressure spikes. The model uses the Schrage equation to calculate the mass transfer, with a different accommodation coefficient for evaporation at the interface, condensation at the interface, and boiling in the bulk liquid. The implicit VOF model was used to account for the moving interface, with bounded second order time discretization. Validation of the models predictions was carried out using microgravity data from the Tank Pressure Control Experiment, which flew aboard the Space Shuttle Mission STS-52. Although this experiment was meant to study pressurization and pressure control, it underwent boiling during several tests. The pressure rise predicted by the CFD model compared well with the experimental data. The ZBOT microgravity experiment is scheduled to fly on February 2016 aboard the ISS. The CFD model was also used to perform simulations for setting parametric limits for the Zero-Boil-Off Tank (ZBOT) Experiments Test Matrix in an attempt to avoid boiling in the majority of the test runs that are aimed to study pressure increase rates during self-pressurization. *Supported in part by NASA ISS Physical Sciences Research Program, NASA HQ, USA

The Listeria monocytogenes Bile Stimulon under Acidic Conditions Is Characterized by Strain-Specific Patterns and the Upregulation of Motility, Cell Wall Modification Functions, and the PrfA Regulon

Science.gov (United States)

Guariglia-Oropeza, Veronica; Orsi, Renato H.; Guldimann, Claudia; Wiedmann, Martin; Boor, Kathryn J.

2018-01-01

Listeria monocytogenes uses a variety of transcriptional regulation strategies to adapt to the extra-host environment, the gastrointestinal tract, and the intracellular host environment. While the alternative sigma factor SigB has been proposed to be a key transcriptional regulator that facilitates L. monocytogenes adaptation to the gastrointestinal environment, the L. monocytogenes' transcriptional response to bile exposure is not well-understood. RNA-seq characterization of the bile stimulon was performed in two L. monocytogenes strains representing lineages I and II. Exposure to bile at pH 5.5 elicited a large transcriptomic response with ~16 and 23% of genes showing differential transcription in 10403S and H7858, respectively. The bile stimulon includes genes involved in motility and cell wall modification mechanisms, as well as genes in the PrfA regulon, which likely facilitate survival during the gastrointestinal stages of infection that follow bile exposure. The fact that bile exposure induced the PrfA regulon, but did not induce further upregulation of the SigB regulon (beyond that expected by exposure to pH 5.5), suggests a model where at the earlier stages of gastrointestinal infection (e.g., acid exposure in the stomach), SigB-dependent gene expression plays an important role. Subsequent exposure to bile induces the PrfA regulon, potentially priming L. monocytogenes for subsequent intracellular infection stages. Some members of the bile stimulon showed lineage- or strain-specific distribution when 27 Listeria genomes were analyzed. Even though sigB null mutants showed increased sensitivity to bile, the SigB regulon was not found to be upregulated in response to bile beyond levels expected by exposure to pH 5.5. Comparison of wildtype and corresponding ΔsigB strains newly identified 26 SigB-dependent genes, all with upstream putative SigB-dependent promoters. PMID:29467736

NASA Microgravity Materials Science Conference

Science.gov (United States)

Gillies, D. C. (Compiler); McCauley, D. E. (Compiler)

1999-01-01

The Microgravity Materials Science Conference was held July 14-16, 1998 at the Von Braun Center in Huntsville, AL. It was organized by the Microgravity Materials Science Discipline Working Group, sponsored by the Microgravity Research Division at NASA Headquarters, and hosted by the NASA Marshall Space Flight Center and the Alliance for Microgravity Materials Science and Applications. It was the third NASA conference of this type in the microgravity materials science discipline. The microgravity science program sponsored approximately 125 investigations and 100 principal investigators in FY98, almost all of whom made oral or poster presentations at this conference. The conference's purpose was to inform the materials science community of research opportunities in reduced gravity in preparation for a NASA Research Announcement scheduled for release in late 1998 by the Microgravity Research Division at NASA Headquarters. The conference was aimed at materials science researchers from academia, industry, and government. A tour of the Marshall Space Flight Center microgravity research facilities was held on July 16, 1998. This volume is comprised of the research reports submitted by the principal investigators after the conference.

Genome-wide analysis of the RpoN regulon in Geobacter sulfurreducens

Directory of Open Access Journals (Sweden)

Núñez Cinthia

2009-07-01

Full Text Available Abstract Background The role of the RNA polymerase sigma factor RpoN in regulation of gene expression in Geobacter sulfurreducens was investigated to better understand transcriptional regulatory networks as part of an effort to develop regulatory modules for genome-scale in silico models, which can predict the physiological responses of Geobacter species during groundwater bioremediation or electricity production. Results An rpoN deletion mutant could not be obtained under all conditions tested. In order to investigate the regulon of the G. sulfurreducens RpoN, an RpoN over-expression strain was made in which an extra copy of the rpoN gene was under the control of a taclac promoter. Combining both the microarray transcriptome analysis and the computational prediction revealed that the G. sulfurreducens RpoN controls genes involved in a wide range of cellular functions. Most importantly, RpoN controls the expression of the dcuB gene encoding the fumarate/succinate exchanger, which is essential for cell growth with fumarate as the terminal electron acceptor in G. sulfurreducens. RpoN also controls genes, which encode enzymes for both pathways of ammonia assimilation that is predicted to be essential under all growth conditions in G. sulfurreducens. Other genes that were identified as part of the RpoN regulon using either the computational prediction or the microarray transcriptome analysis included genes involved in flagella biosynthesis, pili biosynthesis and genes involved in central metabolism enzymes and cytochromes involved in extracellular electron transfer to Fe(III, which are known to be important for growth in subsurface environment or electricity production in microbial fuel cells. The consensus sequence for the predicted RpoN-regulated promoter elements is TTGGCACGGTTTTTGCT. Conclusion The G. sulfurreducens RpoN is an essential sigma factor and a global regulator involved in a complex transcriptional network controlling a variety of

An Integrated Model of the Cardiovascular and Central Nervous Systems for Analysis of Microgravity Induced Fluid Redistribution

Science.gov (United States)

Price, R.; Gady, S.; Heinemann, K.; Nelson, E. S.; Mulugeta, L.; Ethier, C. R.; Samuels, B. C.; Feola, A.; Vera, J.; Myers, J. G.

2015-01-01

A recognized side effect of prolonged microgravity exposure is visual impairment and intracranial pressure (VIIP) syndrome. The medical understanding of this phenomenon is at present preliminary, although it is hypothesized that the headward shift of bodily fluids in microgravity may be a contributor. Computational models can be used to provide insight into the origins of VIIP. In order to further investigate this phenomenon, NASAs Digital Astronaut Project (DAP) is developing an integrated computational model of the human body which is divided into the eye, the cerebrovascular system, and the cardiovascular system. This presentation will focus on the development and testing of the computational model of an integrated model of the cardiovascular system (CVS) and central nervous system (CNS) that simulates the behavior of pressures, volumes, and flows within these two physiological systems.

Definition of the sigma(W) Regulon of Bacillus subtilis in the Absence of Stress

NARCIS (Netherlands)

Zweers, Jessica C.; Nicolas, Pierre; Wiegert, Thomas; van Dijl, Jan Maarten; Denham, Emma L.

2012-01-01

Bacteria employ extracytoplasmic function (ECF) sigma factors for their responses to environmental stresses. Despite intensive research, the molecular dissection of ECF sigma factor regulons has remained a major challenge due to overlaps in the ECF sigma factor-regulated genes and the stimuli that

Lex marks the spot: the virulent side of SOS and a closer look at the LexA regulon.

Science.gov (United States)

Kelley, William L

2006-12-01

The SOS response that responds to DNA damage induces many genes that are under LexA repression. A detailed examination of LexA regulons using genome-wide techniques has recently been undertaken in both Escherichia coli and Bacillus subtilis. These extensive and elegant studies have now charted the extent of the LexA regulons, uncovered many new genes, and exposed a limited overlap in the LexA regulon between the two bacteria. As more bacterial genomes are analysed, more curiosities in LexA regulons arise. Several notable examples include the discovery of a LexA-like protein, HdiR, in Lactococcus lactis, organisms with two lexA genes, and small DNA damage-inducible cassettes under LexA control. In the cyanobacterium Synechocystis, genetic and microarray studies demonstrated that a LexA paralogue exerts control over an entirely different set of carbon-controlled genes and is crucial to cells facing carbon starvation. An examination of SOS induction evoked by common therapeutic drugs has shed new light on unsuspected consequences of drug exposure. Certain antibiotics, most notably fluoroquinolones such as ciprofloxacin, can induce an SOS response and can modulate the spread of virulence factors and drug resistance. SOS induction by beta-lactams in E. coli triggers a novel form of antibiotic defence that involves cell wall stress and signal transduction by the DpiAB two-component system. In this review, we provide an overview of these new directions in SOS and LexA research with emphasis on a few themes: identification of genes under LexA control, the identification of new endogenous triggers, and antibiotic-induced SOS response and its consequences.

In silico discovery of the dormancy regulons in a number of Actinobacteria genomes

Energy Technology Data Exchange (ETDEWEB)

Gerasimova, Anna; Dubchak, Inna; Arkin, Adam; Gelfand, Mikhail

2010-11-16

Mycobacterium tuberculosis is a dangerous Actinobacteria infecting nearly one third of the human population. It becomes dormant and phenotypically drug resistant in response to stresses. An important feature of the M. tuberculosis pathogenesis is the prevalence of latent infection without disease, making understanding of the mechanisms used by the bacteria to exist in this state and to switch to metabolically active infectious form a vital problem to consider. M. tuberculosis dormancy is regulated by the three-component regulatory system of two kinases (DosT and DevS) and transcriprional regulator (DevR). DevR activates transcription of a set of genes, which allow the bacteria to survive long periods of anaerobiosis, and may be important for long-term survival within the host during latent infection. The DevR-regulon is studied experimentally in M. tuberculosis and few other phylogenetically close Mycobacteria spp. As many other two-component systems, the devRS operon is autoregulated. However, the mechanism of the dormancy is not completely clear even for these bacteria and there is no data describing the dormancy regulons in other species.

A Test of Macromolecular Crystallization in Microgravity: Large, Well-Ordered Insulin Crystals

Science.gov (United States)

Borgstahl, Gloria E. O.; Vahedi-Faridi, Ardeschir; Lovelace, Jeff; Bellamy, Henry D.; Snell, Edward H.; Whitaker, Ann F. (Technical Monitor)

2001-01-01

Crystals of insulin grown in microgravity on space shuttle mission STS-95 were extremely well-ordered and unusually large (many > 2 mm). The physical characteristics of six microgravity and six earth-grown crystals were examined by X-ray analysis employing superfine f slicing and unfocused synchrotron radiation. This experimental setup allowed hundreds of reflections to be precisely examined for each crystal in a short period of time. The microgravity crystals were on average 34 times larger, had 7 times lower mosaicity, had 54 times higher reflection peak heights and diffracted to significantly higher resolution than their earth grown counterparts. A single mosaic domain model could account for reflections in microgravity crystals whereas reflections from earth crystals required a model with multiple mosaic domains. This statistically significant and unbiased characterization indicates that the microgravity environment was useful for the improvement of crystal growth and resultant diffraction quality in insulin crystals and may be similarly useful for macromolecular crystals in general.

Unified flow regime predictions at earth gravity and microgravity

International Nuclear Information System (INIS)

Crowley, C.J.

1990-01-01

This paper illustrates the mechanistic models developed to predict flow regime transitions at earth gravity for various pipe inclinations can be successfully applied to existing microgravity flow regime data from several experiments. There is a tendency in the literature for flow regime comparisons in several inclination ranges and at various gravity (acceleration) levels to be treated by separate models, resulting in a proliferation of models for the prediction of flow regimes. One set of mechanistic models can be used to model the transitions between stratified, slug, bubbly, and annular flow regimes in pipes for all acceleration vectors and magnitudes from earth gravity to microgravity

The Biophysics Microgravity Initiative

Science.gov (United States)

Gorti, S.

2016-01-01

Biophysical microgravity research on the International Space Station using biological materials has been ongoing for several decades. The well-documented substantive effects of long duration microgravity include the facilitation of the assembly of biological macromolecules into large structures, e.g., formation of large protein crystals under micro-gravity. NASA is invested not only in understanding the possible physical mechanisms of crystal growth, but also promoting two flight investigations to determine the influence of µ-gravity on protein crystal quality. In addition to crystal growth, flight investigations to determine the effects of shear on nucleation and subsequent formation of complex structures (e.g., crystals, fibrils, etc.) are also supported. It is now considered that long duration microgravity research aboard the ISS could also make possible the formation of large complex biological and biomimetic materials. Investigations of various materials undergoing complex structure formation in microgravity will not only strengthen NASA science programs, but may also provide invaluable insight towards the construction of large complex tissues, organs, or biomimetic materials on Earth.

Microgravity Outreach and Education

Science.gov (United States)

Rogers, Melissa J. B.; Rosenberg, Carla B.

2000-01-01

The NASA Microgravity Research Program has been actively developing classroom activities and educator's guides since the flight of the First United States Microgravity Laboratory. In addition, various brochures, posters, and exhibit materials have been produced for outreach efforts to the general public and to researchers outside of the program. These efforts are led by the Microgravity Research Outreach/Education team at Marshall Space Flight Center, with classroom material support from the K-12 Educational Program of The National Center for Microgravity Research on Fluids and Combustion (NCMR), general outreach material development by the Microgravity Outreach office at Hampton University, and electronic/media access coordinated by Marshall. The broad concept of the NCMR program is to develop a unique set of microgravity-related educational products that enable effective outreach to the pre-college community by supplementing existing mathematics, science, and technology curricula. The current thrusts of the program include summer teacher and high school internships during which participants help develop educational materials and perform research with NCMR and NASA scientists; a teacher sabbatical program which allows a teacher to concentrate on a major educational product during a full school year; frequent educator workshops held at NASA and at regional and national teachers conferences; a nascent student drop tower experiment competition; presentations and demonstrations at events that also reach the general public; and the development of elementary science and middle school mathematics classroom products. An overview of existing classroom products will be provided, along with a list of pertinent World Wide Web URLs. Demonstrations of some hands on activities will show the audience how simple it can be to bring microgravity into the classroom.

Cross-species comparison of the Burkholderia pseudomallei, Burkholderia thailandensis, and Burkholderia mallei quorum-sensing regulons.

Science.gov (United States)

Majerczyk, Charlotte D; Brittnacher, Mitchell J; Jacobs, Michael A; Armour, Christopher D; Radey, Matthew C; Bunt, Richard; Hayden, Hillary S; Bydalek, Ryland; Greenberg, E Peter

2014-11-01

Burkholderia pseudomallei, Burkholderia thailandensis, and Burkholderia mallei (the Bptm group) are close relatives with very different lifestyles: B. pseudomallei is an opportunistic pathogen, B. thailandensis is a nonpathogenic saprophyte, and B. mallei is a host-restricted pathogen. The acyl-homoserine lactone quorum-sensing (QS) systems of these three species show a high level of conservation. We used transcriptome sequencing (RNA-seq) to define the quorum-sensing regulon in each species, and we performed a cross-species analysis of the QS-controlled orthologs. Our analysis revealed a core set of QS-regulated genes in all three species, as well as QS-controlled factors shared by only two species or unique to a given species. This global survey of the QS regulons of B. pseudomallei, B. thailandensis, and B. mallei serves as a platform for predicting which QS-controlled processes might be important in different bacterial niches and contribute to the pathogenesis of B. pseudomallei and B. mallei. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Cross-Species Comparison of the Burkholderia pseudomallei, Burkholderia thailandensis, and Burkholderia mallei Quorum-Sensing Regulons

Science.gov (United States)

Majerczyk, Charlotte D.; Brittnacher, Mitchell J.; Jacobs, Michael A.; Armour, Christopher D.; Radey, Matthew C.; Bunt, Richard; Hayden, Hillary S.; Bydalek, Ryland

2014-01-01

Burkholderia pseudomallei, Burkholderia thailandensis, and Burkholderia mallei (the Bptm group) are close relatives with very different lifestyles: B. pseudomallei is an opportunistic pathogen, B. thailandensis is a nonpathogenic saprophyte, and B. mallei is a host-restricted pathogen. The acyl-homoserine lactone quorum-sensing (QS) systems of these three species show a high level of conservation. We used transcriptome sequencing (RNA-seq) to define the quorum-sensing regulon in each species, and we performed a cross-species analysis of the QS-controlled orthologs. Our analysis revealed a core set of QS-regulated genes in all three species, as well as QS-controlled factors shared by only two species or unique to a given species. This global survey of the QS regulons of B. pseudomallei, B. thailandensis, and B. mallei serves as a platform for predicting which QS-controlled processes might be important in different bacterial niches and contribute to the pathogenesis of B. pseudomallei and B. mallei. PMID:25182491

Microgravity Investigation of Capillary Driven Imbibition

Science.gov (United States)

Dushin, V. R.; Nikitin, V. F.; Smirnov, N. N.; Skryleva, E. I.; Tyurenkova, V. V.

2018-05-01

The goal of the present paper is to investigate the capillary driven filtration in porous media under microgravity conditions. New mathematical model that allows taking into account the blurring of the front due to the instability of the displacement that is developing at the front is proposed. The constants in the mathematical model were selected on the basis of the experimental data on imbibition into unsaturated porous media under microgravity conditions. The flow under the action of a combination of capillary forces and a constant pressure drop or a constant flux is considered. The effect of capillary forces and the type of wettability of the medium on the displacement process is studied. A criterion in which case the capillary effects are insignificant and can be neglected is established.

Field experiment for investigation of very shallow basement structure by micro-gravity survey; Microgravity tansa no gokusenbu kiban chosa eno tekiyo jikken

Energy Technology Data Exchange (ETDEWEB)

Oshita, K; Nozaki, K [OYO Corp., Tokyo (Japan)

1997-10-22

This paper illustrates the field experiment results in which micro-gravity survey was applied to investigation of very shallow basement structure between a few m and 10 m. Its applicability was discussed. In principle, the micro-gravity survey was conducted at the measuring points in a grid with 20 m pitch. Measuring points of 174 were used. The gravity system used for the measurements is an automatic gravimeter CG-3M made by the Scintrex. Survey results of P-wave reflection method conducted at the site using a vibrator focus were used as control data of micro-gravity survey. Consequently, change in the thickness of surface layer (earth filling) shallower than the depth of -10 m could be grasped as a plane. It was found that the micro-gravity survey is a useful method for the investigation of very shallow basement structure. Survey results by the reflection method could contribute to the determination of trend face at filtration and construction of density model as well as the geologic interpretation of gravity anomaly. As a result, reliability of micro-gravity survey and reflection method could be enhanced, mutually. 3 refs., 8 figs.

Microgravity: Teacher's guide with activities for physical science

Science.gov (United States)

Vogt, Gregory L.; Wargo, Michael J.; Rosenberg, Carla B. (Editor)

1995-01-01

This guide is an educational tool for teachers of grades 5 through 12. It is an introduction to microgravity and its application to spaceborne laboratory experiments. Specific payloads and missions are mentioned with limited detail, including Spacelab, the International Microgravity Laboratory, and the United States Microgravity Laboratory. Activities for students demonstrate chemistry, mathematics, and physics applications of microgravity. Activity objectives include: modeling how satellites orbit Earth; demonstrating that free fall eliminates the local effects of gravity; measuring the acceleration environments created by different motions; using a plasma sheet to observe acceleration forces that are experienced on board a space vehicle; demonstrating how mass can be measured in microgravity; feeling how inertia affects acceleration; observing the gravity-driven fluid flow that is caused by differences in solution density; studying surface tension and the fluid flows caused by differences in surface tension; illustrating the effects of gravity on the burning rate of candles; observing candle flame properties in free fall; measuring the contact angle of a fluid; illustrating the effects of gravity and surface tension on fiber pulling; observing crystal growth phenomena in a 1-g environment; investigating temperature effects on crystal growth; and observing crystal nucleation and growth rate during directional solidification. Each activity includes a background section, procedure, and follow-up questions.

Transcriptome analysis of the Lactococcus lactis ArgR and AhrC regulons

DEFF Research Database (Denmark)

Larsen, Rasmus; van Hijum, Sacha A. F. T.; Martinussen, Jan

2008-01-01

In previous studies, we have shown that direct protein-protein. interaction between the two regulators ArgR and AhrC in Lactococcus lactis is required for arginine-dependent repression of the biosynthetic argC promoter and the activation of the catabolic arcA promoter. Here, we establish the global...... ArgR and AhrC regulons by transcriptome analyses and show that both regulators are dedicated to the control of arginine metabolism in L. lactis....

Nineteenth International Microgravity Measurements Group Meeting

Science.gov (United States)

DeLombard, Richard (Compiler)

2000-01-01

The Microgravity Measurements Group meetings provide a forum for an exchange of information and ideas about various aspects of microgravity acceleration research in international microgravity research programs. These meetings are sponsored by the PI Microgravity Services (PIMS) project at the NASA Glenn Research Center. The 19th MGMG meeting was held 11-13 July 2000 at the Sheraton Airport Hotel in Cleveland, Ohio. The 44 attendees represented NASA, other space agencies, universities, and commercial companies; 8 of the attendees were international representatives from Japan, Italy, Canada, Russia, and Germany. Twenty-seven presentations were made on a variety of microgravity environment topics including the International Space Station (ISS), acceleration measurement and analysis results, science effects from microgravity accelerations, vibration isolation, free flyer satellites, ground testing, vehicle characterization, and microgravity outreach and education. The meeting participants also toured three microgravity-related facilities at the NASA Glenn Research Center. Contained within the minutes is the conference agenda, which indicates each speaker, the title of their presentation, and the actual time of their presentation. The minutes also include the charts for each presentation, which indicate the authors' name(s) and affiliation. In some cases, a separate written report was submitted and has been Included here

Liquid-Gas-Like Phase Transition in Sand Flow Under Microgravity

Science.gov (United States)

Huang, Yu; Zhu, Chongqiang; Xiang, Xiang; Mao, Wuwei

2015-06-01

In previous studies of granular flow, it has been found that gravity plays a compacting role, causing convection and stratification by density. However, there is a lack of research and analysis of the characteristics of different particles' motion under normal gravity contrary to microgravity. In this paper, we conduct model experiments on sand flow using a model test system based on a drop tower under microgravity, within which the characteristics and development processes of granular flow under microgravity are captured by high-speed cameras. The configurations of granular flow are simulated using a modified MPS (moving particle simulation), which is a mesh-free, pure Lagrangian method. Moreover, liquid-gas-like phase transitions in the sand flow under microgravity, including the transitions to "escaped", "jumping", and "scattered" particles are highlighted, and their effects on the weakening of shear resistance, enhancement of fluidization, and changes in particle-wall and particle-particle contact mode are analyzed. This study could help explain the surface geology evolution of small solar bodies and elucidate the nature of granular interaction.

Microgravity Platforms

Science.gov (United States)

Del Basso, Steve

2000-01-01

The world's space agencies have been conducting microgravity research since the beginning of space flight. Initially driven by the need to understand the impact of less than- earth gravity physics on manned space flight, microgravity research has evolved into a broad class of scientific experimentation that utilizes extreme low acceleration environments. The U.S. NASA microgravity research program supports both basic and applied research in five key areas: biotechnology - focusing on macro-molecular crystal growth as well as the use of the unique space environment to assemble and grow mammalian tissue; combustion science - focusing on the process of ignition, flame propagation, and extinction of gaseous, liquid, and solid fuels; fluid physics - including aspects of fluid dynamics and transport phenomena; fundamental physics - including the study of critical phenomena, low-temperature, atomic, and gravitational physics; and materials science - including electronic and photonic materials, glasses and ceramics, polymers, and metals and alloys. Similar activities prevail within the Chinese, European, Japanese, and Russian agencies with participation from additional international organizations as well. While scientific research remains the principal objective behind these program, all hope to drive toward commercialization to sustain a long range infrastructure which .benefits the national technology and economy. In the 1997 International Space Station Commercialization Study, conducted by the Potomac Institute for Policy Studies, some viable microgravity commercial ventures were identified, however, none appeared sufficiently robust to privately fund space access at that time. Thus, government funded micro gravity research continues on an evolutionary path with revolutionary potential.

Study of the factors affecting the karst volume assessment in the Dead Sea sinkhole problem using microgravity field analysis and 3-D modeling

Directory of Open Access Journals (Sweden)

L. V. Eppelbaum

2008-11-01

Full Text Available Thousands of sinkholes have appeared in the Dead Sea (DS coastal area in Israel and Jordan during two last decades. The sinkhole development is recently associated with the buried evaporation karst at the depth of 25–50 m from earth's surface caused by the drop of the DS level at the rate of 0.8–1.0 m/yr. Drop in the Dead Sea level has changed hydrogeological conditions in the subsurface and caused surface to collapse. The pre-existing cavern was detected using microgravity mapping in the Nahal Hever South site where seven sinkholes of 1–2 m diameter had been opened. About 5000 gravity stations were observed in the area of 200×200 m² by the use of Scintrex CG-3M AutoGrav gravimeter. Besides the conventional set of corrections applied in microgravity investigations, a correction for a strong gravity horizontal gradient (DS Transform Zone negative gravity anomaly influence was inserted. As a result, residual gravity anomaly of –(0.08÷0.14 mGal was revealed. The gravity field analysis was supported by resistivity measurements. We applied the Emigma 7.8 gravity software to create the 3-D physical-geological models of the sinkholes development area. The modeling was confirmed by application of the GSFC program developed especially for 3-D combined gravity-magnetic modeling in complicated environments. Computed numerous gravity models verified an effective applicability of the microgravity technology for detection of karst cavities and estimation of their physical-geological parameters. A volume of the karst was approximately estimated as 35 000 m³. The visual analysis of large sinkhole clusters have been forming at the microgravity anomaly site, confirmed the results of microgravity mapping and 3-D modeling.

Numerical simulation of gender differences in a long-term microgravity exposure

Science.gov (United States)

Perez-Poch, Antoni

The objective of this work is to analyse and simulate gender differences when individuals are exposed to long-term microgravity. Risk probability of a health impairment which may put in jeopardy a long-term mission is also evaluated. Computer simulations are becoming a promising research line of work, as physiological models become more and more sophisticated and reliable. Technological advances in state-of-the-art hardware technology and software allow nowadays for better and more accurate simulations of complex phenomena, such as the response of the human cardiovascular system to long-term exposure to microgravity. Experimental data for long-term missions are difficult to achieve and reproduce, therefore the predictions of computer simulations are of a major importance in this field. Our approach is based on a previous model developed and implemented in our laboratory (NELME: Numerical Evaluation of Long-term Microgravity Effects). The software simulates the behaviour of the cardiovascular system and different human organs, has a modular architecture, and allows to introduce perturbations such as physical exercise or countermeasures. The implementation is based on a complex electricallike model of this control system, using inexpensive software development frameworks, and has been tested and validated with the available experimental data. Gender differences have been implemented for this specific work, as an adjustment of a number of parameters that are included in the model. Women versus men physiological differences have been therefore taken into account, based upon estimations from the physiology bibliography. A number of simulations have been carried out for long-term exposure to microgravity. Gravity varying from Earth-based to zero, and time exposure are the two main variables involved in the construction of results, including responses to patterns of physical aerobical exercise, and also thermal stress simulating an extra-vehicular activity. Results show

Diagnostics in Japan's microgravity experiments

Science.gov (United States)

Kadota, Toshikazu

1995-01-01

The achievement of the combustion research under microgravity depends substantially on the availability of diagnostic systems. The non-intrusive diagnostic systems are potentially applicable for providing the accurate, realistic and detailed information on momentum, mass and energy transport, complex gas phase chemistry, and phase change in the combustion field under microgravity. The non-intrusive nature of optical instruments is essential to the measurement of combustion process under microgravity which is very nervous to any perturbation. However, the implementation of the non-intrusive combustion diagnostic systems under microgravity is accompanied by several constraints. Usually, a very limited space is only available for constructing a highly sophisticated system which is so sensitive that it is easily affected by the magnitude of the gravitational force, vibration and heterogeneous field of temperature and density of the environments. The system should be properly adjusted prior to the experiment. Generally, it is quite difficult to tune the instruments during measurements. The programmed sequence of operation should also be provided. Extensive effort has been toward the development of non-intrusive diagnostic systems available for the combustion experiments under microgravity. This paper aims to describe the current art and the future strategy on the non-intrusive diagnostic systems potentially applicable to the combustion experiments under microgravity in Japan.

Gender differences in organ density in a rat simulated microgravity model

Science.gov (United States)

Pettis, Christopher Ryan; Witten, Mark Lee

2004-01-01

Research investigating the physiological effects of microgravity on the human body has demonstrated a shift of body fluids in actual spaceflight and in simulated Earth-based microgravity models in both males and females, possibly causing many deleterious physiological effects. Twenty-five anatomically normal female (NF) and 20 ovariectomized (OE) Fischer 344 rats were randomly selected to be in an experimental ( 1 h of 45° head-down tilt, 45HDT) or control ( 1 h of prone position) group. At the end of the hour experimental period, the density of the brain, lungs, heart, liver, and left and right kidneys were measured using spiral computed tomography (SCT) while the rats remained in their experimental positions. A sub-group of OE rats ( N=6) was administered estrogen replacement therapy on a daily basis ( 5 μg/kg body weight, s.c.) for 4 days and then underwent 1 h of 45HDT and SCT analysis at one day, 2 days, and 5 days to determine if estrogen replacement therapy would alter organ densities. Our data demonstrate that 1 h of 45HDT produced significant increases ( pbrain, liver, left kidney, and lung of the OE female group compared to their prone controls. However, only the brain density was significantly increased in the NF group. Estrogen replacement therapy caused a significant decrease in brain organ density at the 5 day time point compared to the 24 h time point. We conclude that estrogen plays a role in fluid distribution in a rat 45HDT model.

Cardiopulmonary Resuscitation in Microgravity: Efficacy in the Swine During Parabolic Flight

Science.gov (United States)

Johnston, Smith L.; Campbell, Mark R.; Billica, Roger D.; Gilmore, Stevan M.

2004-01-01

INTRODUCTION: The International Space Station will need to be as capable as possible in providing Advanced Cardiac Life Support (ACLS) and cardiopulmonary resuscitation (CPR). Previous studies with manikins in parabolic microgravity (0 G) have shown that delivering CPR in microgravity is difficult. End tidal carbon dioxide (PetCO2) has been previously shown to be an effective non-invasive tool for estimating cardiac output during cardiopulmonary resuscitation. Animal models have shown that this diagnostic adjunct can be used as a predictor of survival when PetCO2 values are maintained above 25% of pre-arrest values. METHODS: Eleven anesthetized Yorkshire swine were flown in microgravity during parabolic flight. Physiologic parameters, including PetCO2, were monitored. Standard ACLS protocols were used to resuscitate these models after chemical induction of cardiac arrest. Chest compressions were administered using conventional body positioning with waist restraint and unconventional vertical-inverted body positioning. RESULTS: PetCO2 values were maintained above 25% of both 1-G and O-G pre-arrest values in the microgravity environment (33% +/- 3 and 41 +/- 3). No significant difference between 1-G CPR and O-G CPR was found in these animal models. Effective CPR was delivered in both body positions although conventional body positioning was found to be quickly fatiguing as compared with the vertical-inverted. CONCLUSIONS: Cardiopulmonary resuscitation can be effectively administered in microgravity (0 G). Validation of this model has demonstrated that PetCO2 levels were maintained above a level previously reported to be predictive of survival. The unconventional vertical-inverted position provided effective CPR and was less fatiguing as compared with the conventional body position with waist restraints.

Transcriptome analysis of the Dickeya dadantii PecS regulon during the early stages of interaction with Arabidopsis thaliana.

Science.gov (United States)

Pédron, Jacques; Chapelle, Emilie; Alunni, Benoît; Van Gijsegem, Frédérique

2018-03-01

PecS is one of the major global regulators controlling the virulence of Dickeya dadantii, a broad-host-range phytopathogenic bacterium causing soft rot on several plant families. To define the PecS regulon during plant colonization, we analysed the global transcriptome profiles in wild-type and pecS mutant strains during the early colonization of the leaf surfaces and in leaf tissue just before the onset of symptoms, and found that the PecS regulon consists of more than 600 genes. About one-half of these genes are down-regulated in the pecS mutant; therefore, PecS has both positive and negative regulatory roles that may be direct or indirect. Indeed, PecS also controls the regulation of a few dozen regulatory genes, demonstrating that this global regulator is at or near the top of a major regulatory cascade governing adaptation to growth in planta. Notably, PecS acts mainly at the very beginning of infection, not only to prevent virulence gene induction, but also playing an active role in the adaptation of the bacterium to the epiphytic habitat. Comparison of the patterns of gene expression inside leaf tissues and during early colonization of leaf surfaces in the wild-type bacterium revealed 637 genes modulated between these two environments. More than 40% of these modulated genes are part of the PecS regulon, emphasizing the prominent role of PecS during plant colonization. © 2017 BSPP AND JOHN WILEY & SONS LTD.

Effect of low shear modeled microgravity on phenotypic and central chitin metabolism in the filamentous fungi Aspergillus niger and Penicillium chrysogenum.

Science.gov (United States)

Sathishkumar, Yesupatham; Velmurugan, Natarajan; Lee, Hyun Mi; Rajagopal, Kalyanaraman; Im, Chan Ki; Lee, Yang Soo

2014-08-01

Phenotypic and genotypic changes in Aspergillus niger and Penicillium chrysogenum, spore forming filamentous fungi, with respect to central chitin metabolism were studied under low shear modeled microgravity, normal gravity and static conditions. Low shear modeled microgravity (LSMMG) response showed a similar spore germination rate with normal gravity and static conditions. Interestingly, high ratio of multiple germ tube formation of A. niger in LSMMG condition was observed. Confocal laser scanning microscopy images of calcofluor flurophore stained A. niger and P. chrysogenum showed no significant variations between different conditions tested. Transmission electron microscopy images revealed number of mitochondria increased in P. chrysogenum in low shear modeled microgravity condition but no stress related-woronin bodies in fungal hyphae were observed. To gain additional insight into the cell wall integrity under different conditions, transcription level of a key gene involved in cell wall integrity gfaA, encoding the glutamine: fructose-6-phosphate amidotransferase enzyme, was evaluated using qRT-PCR. The transcription level showed no variation among different conditions. Overall, the results collectively indicate that the LSMMG has shown no significant stress on spore germination, mycelial growth, cell wall integrity of potentially pathogenic fungi, A. niger and P. chrysogenum.

A comparison of the low temperature transcriptomes and CBF regulons of three plant species that differ in freezing tolerance: Solanum commersonii, Solanum tuberosum, and Arabidopsis thaliana

OpenAIRE

Carvallo, Marcela A.; Pino, María-Teresa; Jeknić, Zoran; Zou, Cheng; Doherty, Colleen J.; Shiu, Shin-Han; Chen, Tony H. H.; Thomashow, Michael F.

2011-01-01

Solanum commersonii and Solanum tuberosum are closely related plant species that differ in their abilities to cold acclimate; whereas S. commersonii increases in freezing tolerance in response to low temperature, S. tuberosum does not. In Arabidopsis thaliana, cold-regulated genes have been shown to contribute to freezing tolerance, including those that comprise the CBF regulon, genes that are controlled by the CBF transcription factors. The low temperature transcriptomes and CBF regulons of ...

Macromolecular crystallization in microgravity

International Nuclear Information System (INIS)

Snell, Edward H; Helliwell, John R

2005-01-01

Density difference fluid flows and sedimentation of growing crystals are greatly reduced when crystallization takes place in a reduced gravity environment. In the case of macromolecular crystallography a crystal of a biological macromolecule is used for diffraction experiments (x-ray or neutron) so as to determine the three-dimensional structure of the macromolecule. The better the internal order of the crystal then the greater the molecular structure detail that can be extracted. It is this structural information that enables an understanding of how the molecule functions. This knowledge is changing the biological and chemical sciences, with major potential in understanding disease pathologies. In this review, we examine the use of microgravity as an environment to grow macromolecular crystals. We describe the crystallization procedures used on the ground, how the resulting crystals are studied and the knowledge obtained from those crystals. We address the features desired in an ordered crystal and the techniques used to evaluate those features in detail. We then introduce the microgravity environment, the techniques to access that environment and the theory and evidence behind the use of microgravity for crystallization experiments. We describe how ground-based laboratory techniques have been adapted to microgravity flights and look at some of the methods used to analyse the resulting data. Several case studies illustrate the physical crystal quality improvements and the macromolecular structural advances. Finally, limitations and alternatives to microgravity and future directions for this research are covered. Macromolecular structural crystallography in general is a remarkable field where physics, biology, chemistry and mathematics meet to enable insight to the fundamentals of life. As the reader will see, there is a great deal of physics involved when the microgravity environment is applied to crystallization, some of it known, and undoubtedly much yet to

The Distinctive Sensitivity to Microgravity of Immune Cell Subpopulations

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Chen, Hui; Luo, Haiying; Liu, Jing; Wang, Peng; Dong, Dandan; Shang, Peng; Zhao, Yong

2015-11-01

Immune dysfunction in astronauts is well documented after spaceflights. Microgravity is one of the key factors directly suppressing the function of immune system. However, it is unclear which subpopulations of immune cells including innate and adaptive immune cells are more sensitive to microgravity We herein investigated the direct effects of modeled microgravity (MMg) on different immune cells in vitro. Mouse splenocytes, thymocytes and bone marrow cells were exposed to MMg for 16 hrs. The survival and the phenotypes of different subsets of immune cells including CD4+T cells, CD8+T cells, CD4+Foxp3+ regulatory T cells (Treg), B cells, monocytes/macrophages, dendritic cells (DCs), natural killer cells (NK) were determined by flow cytometry. After splenocytes were cultured under MMg for 16h, the cell frequency and total numbers of monocytes, macrophages and CD4+Foxp3+T cells were significantly decreased more than 70 %. MMg significantly decreased the cell numbers of CD8+ T cells, B cells and neutrophils in splenocytes. The cell numbers of CD4+T cells and NK cells were unchanged significantly when splenocytes were cultured under MMg compared with controls. However, MMg significantly increased the ratio of mature neutrophils to immature neutrophils in bone marrow and the cell number of DCs in splenocytes. Based on the cell survival ability, monocytes, macrophages and CD4+Foxp3+Treg cells are most sensitive to microgravity; CD4+T cells and NK cells are resistant to microgravity; CD8+T cells and neutrophils are impacted by short term microgravity exposure. Microgravity promoted the maturation of neutrophils and development of DCs in vitro. The present studies offered new insights on the direct effects of MMg on the survival and homeostasis of immune cell subsets.

Humoral Responses to Rv1733c, Rv0081, Rv1735c, and Rv1737c DosR Regulon-Encoded Proteins of Mycobacterium tuberculosis in Individuals with Latent Tuberculosis Infection

Directory of Open Access Journals (Sweden)

Simon G. Kimuda

2017-01-01

Full Text Available Latent tuberculosis infection (LTBI is evidence of immunological control of tuberculosis. Dormancy survival regulator (DosR regulon-encoded proteins may have a role in the maintenance of LTBI. T cell responses to Rv1733c, Rv0081, Rv1735c, and Rv1737c DosR regulon-encoded proteins were found to be most frequent among household contacts of TB cases from Uganda compared to other DosR proteins, but antibody responses were not described. We characterized antibody responses to these proteins in individuals from Uganda. Antibodies to Rv1733c, Rv0081, Rv1735c, and Rv1737c DosR regulon-encoded proteins were measured in 68 uninfected individuals, 62 with LTBI, and 107 with active pulmonary tuberculosis (APTB cases. There were no differences in the concentrations of antibodies to Rv0081, Rv1735c, and Rv1737c DosR regulon-encoded proteins between individuals with LTBI and APTB and those who were uninfected. LTBI was associated with higher concentrations of antibodies to Rv1733c in female participants [adjusted geometric mean ratio: 1.812, 95% confidence interval (CI: 1.105 2.973, and p=0.019] but not in males (p value for interaction = 0.060. Antibodies to the four DosR regulon-encoded proteins investigated may not serve as good biomarkers of LTBI in the general population. More of the M.tb proteome needs to be screened to identify proteins that induce strong antibody responses in LTBI.

Quantitative Measurement of Oxygen in Microgravity Combustion

Science.gov (United States)

Silver, Joel A.

1997-01-01

A low-gravity environment, in space or in ground-based facilities such as drop towers, provides a unique setting for studying combustion mechanisms. Understanding the physical phenomena controlling the ignition and spread of flames in microgravity has importance for space safety as well as for better characterization of dynamical and chemical combustion processes which are normally masked by buoyancy and other gravity-related effects. Due to restrictions associated with performing measurements in reduced gravity, diagnostic methods which have been applied to microgravity combustion studies have generally been limited to capture of flame emissions on film or video, laser Schlieren imaging and (intrusive) temperature measurements using thermocouples. Given the development of detailed theoretical models, more sophisticated diagnostic methods are needed to provide the kind of quantitative data necessary to characterize the properties of microgravity combustion processes as well as provide accurate feedback to improve the predictive capabilities of the models. When the demands of space flight are considered, the need for improved diagnostic systems which are rugged, compact, reliable, and operate at low power becomes apparent. The objective of this research is twofold. First, we want to develop a better understanding of the relative roles of diffusion and reaction of oxygen in microgravity combustion. As the primary oxidizer species, oxygen plays a major role in controlling the observed properties of flames, including flame front speed (in solid or liquid flames), extinguishment characteristics, flame size and flame temperature. The second objective is to develop better diagnostics based on diode laser absorption which can be of real value in both microgravity combustion research and as a sensor on-board Spacelab as either an air quality monitor or as part of a fire detection system. In our prior microgravity work, an eight line-of-sight fiber optic system measured

Response of Human Prostate Cancer Cells to Mitoxantrone Treatment in Simulated Microgravity Environment

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Zhang, Ye; Wu, Honglu

2012-07-01

RESPONSE OF HUMAN PROSTATE CANCER CELLS TO MITOXANTRONE TREATMENT IN SIMULATED MICROGRAVITY ENVIRONMENT Ye Zhang1,2, Christopher Edwards3, and Honglu Wu1 1 NASA-Johnson Space Center, Houston, TX 2 Wyle Integrated Science and Engineering Group, Houston, TX 3 Oregon State University, Corvallis, OR This study explores the changes in growth of human prostate cancer cells (LNCaP) and their response to the treatment of an antineoplastic agent, mitoxantrone, under the simulated microgravity condition. In comparison to static 1g, microgravity and simulated microgravity have been shown to alter global gene expression patterns and protein levels in various cultured cell models or animals. However, very little is known about the effect of altered gravity on the responses of cells to the treatment of drugs, especially chemotherapy drugs. To test the hypothesis that zero gravity would result in altered regulations of cells in response to antineoplastic agents, we cultured LNCaP cells in either a High Aspect Ratio Vessel (HARV) bioreactor at the rotating condition to model microgravity in space or in the static condition as control, and treated the cells with mitoxantrone. Cell growth, as well as expressions of oxidative stress related genes, were analyzed after the drug treatment. Compared to static 1g controls, the cells cultured in the simulated microgravity environment did not present significant differences in cell viability, growth rate, or cell cycle distribution. However, after mitoxantrone treatment, a significant proportion of bioreactor cultured cells became apoptotic or was arrested in G2. Several oxidative stress related genes also showed a higher expression level post mitoxantrone treatment. Our results indicate that simulated microgravity may alter the response of LNCaP cells to mitoxantrone treatment. Understanding the mechanisms by which cells respond to drugs differently in an altered gravity environment will be useful for the improvement of cancer treatment on

Preparation for microgravity - The role of the Microgravity Material Science Laboratory

Science.gov (United States)

Johnston, J. Christopher; Rosenthal, Bruce N.; Meyer, Maryjo B.; Glasgow, Thomas K.

1988-01-01

Experiments at the NASA Lewis Research Center's Microgravity Material Science Laboratory using physical and mathematical models to delineate the effects of gravity on processes of scientific and commercial interest are discussed. Where possible, transparent model systems are used to visually track convection, settling, crystal growth, phase separation, agglomeration, vapor transport, diffusive flow, and polymer reactions. Materials studied include metals, alloys, salts, glasses, ceramics, and polymers. Specific technologies discussed include the General Purpose furnace used in the study of metals and crystal growth, the isothermal dendrite growth apparatus, the electromagnetic levitator/instrumented drop tube, the high temperature directional solidification furnace, the ceramics and polymer laboratories and the center's computing facilities.

Research progress on microgravity boiling heat transfer

International Nuclear Information System (INIS)

Xiao Zejun; Chen Bingde

2003-01-01

Microgravity boiling heat transfer is one of the most basic research topics in aerospace technology, which is important for both scientific research and engineering application. Research progress on microgravity boiling heat transfer is presented, including terrestrial simulation technique, terrestrial simulation experiment, microgravity experiment, and flow boiling heat transfer

Proteomic analysis of zebrafish embryos exposed to simulated-microgravity

Science.gov (United States)

Hang, Xiaoming; Ma, Wenwen; Wang, Wei; Liu, Cong; Sun, Yeqing

Microgravity can induce a serial of physiological and pathological changes in human body, such as cardiovascular functional disorder, bone loss, muscular atrophy and impaired immune system function, etc. In this research, we focus on the influence of microgravity to vertebrate embryo development. As a powerful model for studying vertebrate development, zebrafish embryos at 8 hpf (hour past fertilization) and 24 hpf were placed into a NASA developed bioreac-tor (RCCS) to simulate microgravity for 64 and 48 hours, respectively. The same number of control embryos from the same parents were placed in a tissue culture dish at the same temper-ature of 28° C. Each experiment was repeated 3 times and analyzed by two-dimensional (2-D) gel electrophoresis. Image analysis of silver stained 2-D gels revealed that 64 from total 292 protein spots showed quantitative and qualitative variations that were significantly (P<0.05) and reproducibly different between simulate-microgravity treatment and the stationary control samples. 4 protein spots with significant expression alteration (P<0.01) were excised from 2-D gels and analyzed by MALDI-TOF/TOF mass spectra primarily. Of these proteins, 3 down-regulated proteins were identified as bectin 2, centrosomal protein of 135kDa and tropomyosin 4, while the up-regulated protein was identified as creatine kinase muscle B. Other protein spots showed significant expression alteration will be identified successively and the corresponding genes expression will also be measured by Q-PCR method at different development stages. The data presented in this study illustrate that zebrafish embryo can be significantly induced by microgravity on the expression of proteins involved in bone and muscle formation. Key Words: Danio rerio; Simulated-microgravity; Proteomics

Estimated Muscle Loads During Squat Exercise in Microgravity Conditions

Science.gov (United States)

Fregly, Christopher D.; Kim, Brandon T.; Li, Zhao; DeWitt, John K.; Fregly, Benjamin J.

2012-01-01

Loss of muscle mass in microgravity is one of the primary factors limiting long-term space flight. NASA researchers have developed a number of exercise devices to address this problem. The most recent is the Advanced Resistive Exercise Device (ARED), which is currently used by astronauts on the International Space Station (ISS) to emulate typical free-weight exercises in microgravity. ARED exercise on the ISS is intended to reproduce Earth-level muscle loads, but the actual muscle loads produced remain unknown as they cannot currently be measured directly. In this study we estimated muscle loads experienced during squat exercise on ARED in microgravity conditions representative of Mars, the moon, and the ISS. The estimates were generated using a subject-specific musculoskeletal computer model and ARED exercise data collected on Earth. The results provide insight into the capabilities and limitations of the ARED machine.

Cytomorphometric changes in hippocampal CA1 neurons exposed to simulated microgravity using rats as model

Directory of Open Access Journals (Sweden)

Amit eRanjan

2014-05-01

Full Text Available Microgravity and sleep loss lead to cognitive and learning deficits. These behavioral alterations are likely to be associated with cytomorphological changes and loss of neurons. To understand the phenomenon, we exposed rats (225-275g to 14 days simulated microgravity (SMg and compared its effects on CA1 hippocampal neuronal plasticity, with that of normal cage control rats. We observed that the mean area, perimeter, synaptic cleft and length of active zone of CA1 hippocampal neurons significantly decreased while dendritic arborization and number of spines significantly increased in SMg group as compared with controls. The mean thickness of the post synaptic density and total dendritic length remained unaltered. The changes may be a compensatory effect induced by exposure to microgravity; however, the effects may be transient or permanent, which need further study. These findings may be useful for designing effective prevention for those, including the astronauts, exposed to microgravity. Further, subject to confirmation we propose that SMg exposure might be useful for recovery of stroke patients.

Loss of signal transduction and inhibition of lymphocyte locomotion in a ground-based model of microgravity

Science.gov (United States)

Sundaresan, Alamelu; Risin, Diana; Pellis, Neal R.; McIntire, L. V. (Principal Investigator)

2002-01-01

Inflammatory adherence to, and locomotion through the interstitium is an important component of the immune response. Conditions such as microgravity and modeled microgravity (MMG) severely inhibit lymphocyte locomotion in vitro through gelled type I collagen. We used the NASA rotating wall vessel bioreactor or slow-turning lateral vessel as a prototype for MMG in ground-based experiments. Previous experiments from our laboratory revealed that when lymphocytes (human peripheral blood mononuclear cells [PBMCs]) were first activated with phytohemaglutinin followed by exposure to MMG, locomotory capacity was not affected. In the present study, MMG inhibits lymphocyte locomotion in a manner similar to that observed in microgravity. Phorbol myristate acetate (PMA) treatment of PBMCs restored lost locomotory capacity by a maximum of 87%. Augmentation of cellular calcium flux with ionomycin had no restorative effect. Treatment of lymphocytes with mitomycin C prior to exposure to MMG, followed by PMA, restored locomotion to the same extent as when nonmitomycin C-treated lymphocytes were exposed to MMG (80-87%), suggesting that deoxyribonucleic acid replication is not essential for the restoration of locomotion. Thus, direct activation of protein kinase C (PKC) with PMA was effective in restoring locomotion in MMG comparable to the normal levels seen in Ig cultures. Therefore, in MMG, lymphocyte calcium signaling pathways were functional, with defects occurring at either the level of PKC or upstream of PKC.

Microarray Profile of Gene Expression during Osteoclast Differentiation in Modeled Microgravity

Data.gov (United States)

National Aeronautics and Space Administration — Microgravity leads to a 10-15% loss of bone mass in astronauts during space flight. Osteoclast is the multinucleated bone resorbing cell. In this study we used NASA...

Containerless solidification of BiFeO3 oxide under microgravity

Science.gov (United States)

Yu, Jianding; Arai, Yasutomo; Koshikawa, Naokiyo; Ishikawa, Takehito; Yoda, Shinichi

1999-07-01

Containerless solidification of BiFeO3 oxide has been carried out under microgravity with Electrostatic Levitation Furnace (ELF) aboard on the sounding rocket (TR-IA). It is a first containerless experiment using ELF under microgravity for studying the solidification of oxide insulator material. Spherical BiFeO3 sample with diameter of 5mm was heated by two lasers in oxygen and nitrogen mixing atmosphere, and the sample position by electrostatic force under pinpoint model and free drift model. In order to compare the solidification behavior in microgravity with on ground, solidification experiments of BiFeO3 in crucible and drop tube were carried out. In crucible experiment, it was very difficult to get single BiFeO3 phase, because segregation of Fe2O3 occured very fast and easily. In drop tube experiment, fine homogeneous BiFeO3 microstructure was obtained in a droplet about 300 μm. It implies that containerless processing can promote the phase selection in solidification. In microgravity experiment, because the heating temperature was lower than that of estimated, the sample was heated into Fe2O3+liquid phase region. Fe2O3 single crystal grew on the surface of the spherical sample, whose sample was clearly different from that observed in ground experiments.

A Geology Sampling System for Microgravity Bodies

Science.gov (United States)

Hood, Anthony; Naids, Adam

2016-01-01

Human exploration of microgravity bodies is being investigated as a precursor to a Mars surface mission. Asteroids, comets, dwarf planets, and the moons of Mars all fall into this microgravity category and some are been discussed as potential mission targets. Obtaining geological samples for return to Earth will be a major objective for any mission to a microgravity body. Currently the knowledge base for geology sampling in microgravity is in its infancy. Humans interacting with non-engineered surfaces in microgravity environment pose unique challenges. In preparation for such missions a team at the NASA Johnson Space Center has been working to gain experience on how to safely obtain numerous sample types in such an environment. This paper describes the type of samples the science community is interested in, highlights notable prototype work, and discusses an integrated geology sampling solution.

Development of life sciences equipment for microgravity and hypergravity simulation

Science.gov (United States)

Mulenburg, G. M.; Evans, J.; Vasques, M.; Gundo, D. P.; Griffith, J. B.; Harper, J.; Skundberg, T.

1994-01-01

The mission of the Life Science Division at the NASA Ames Research Center is to investigate the effects of gravity on living systems in the spectrum from cells to humans. The range of these investigations is from microgravity, as experienced in space, to Earth's gravity, and hypergravity. Exposure to microgravity causes many physiological changes in humans and other mammals including a headward shift of body fluids, atrophy of muscles - especially the large muscles of the legs - and changes in bone and mineral metabolism. The high cost and limited opportunity for research experiments in space create a need to perform ground based simulation experiments on Earth. Models that simulate microgravity are used to help identify and quantify these changes, to investigate the mechanisms causing these changes and, in some cases, to develop countermeasures.

Macromolecular crystallization in microgravity generated by a superconducting magnet.

Science.gov (United States)

Wakayama, N I; Yin, D C; Harata, K; Kiyoshi, T; Fujiwara, M; Tanimoto, Y

2006-09-01

About 30% of the protein crystals grown in space yield better X-ray diffraction data than the best crystals grown on the earth. The microgravity environments provided by the application of an upward magnetic force constitute excellent candidates for simulating the microgravity conditions in space. Here, we describe a method to control effective gravity and formation of protein crystals in various levels of effective gravity. Since 2002, the stable and long-time durable microgravity generated by a convenient type of superconducting magnet has been available for protein crystal growth. For the first time, protein crystals, orthorhombic lysozyme, were grown at microgravity on the earth, and it was proved that this microgravity improved the crystal quality effectively and reproducibly. The present method always accompanies a strong magnetic field, and the magnetic field itself seems to improve crystal quality. Microgravity is not always effective for improving crystal quality. When we applied this microgravity to the formation of cubic porcine insulin and tetragonal lysozyme crystals, we observed no dependence of effective gravity on crystal quality. Thus, this kind of test will be useful for selecting promising proteins prior to the space experiments. Finally, the microgravity generated by the magnet is compared with that in space, considering the cost, the quality of microgravity, experimental convenience, etc., and the future use of this microgravity for macromolecular crystal growth is discussed.

PI Microgravity Services Role for International Space Station Operations

Science.gov (United States)

DeLombard, Richard

1998-01-01

During the ISS era, the NASA Lewis Research Center's Principal Investigator Microgravity Services (PIMS) project will provide to principal investigators (PIs) microgravity environment information and characterization of the accelerations to which their experiments were exposed during on orbit operations. PIMS supports PIs by providing them with microgravity environment information for experiment vehicles, carriers, and locations within the vehicle. This is done to assist the PI with their effort to evaluate the effect of acceleration on their experiments. Furthermore, PIMS responsibilities are to support the investigators in the area of acceleration data analysis and interpretation, and provide the Microgravity science community with a microgravity environment characterization of selected experiment carriers and vehicles. Also, PIMS provides expertise in the areas of microgravity experiment requirements, vibration isolation, and the implementation of requirements for different spacecraft to the microgravity community and other NASA programs.

Effect of simulated microgravity on Aspergillus niger

Science.gov (United States)

Pratap, Jeffrey J.

2005-08-01

A rotating bioreactor was developed to simulate microgravity and its influence was studied on fungal growth. The reactor was designed to simulate microgravity using 'free fall' principle, which creates an apparent weightlessness for a brief period of time. In this experiment, a sealed vertically rotating tube is the reactor in which the cells are grown. For the first time vertically rotating tubes were used to obtain 'free fall' thereby simulating microgravity. Simulated microgravity served significant in the alteration of growth and productivity of Aspergillus niger, a common soil fungi. Two other sets of similar cultures were maintained as still and shake control cultures to compare with the growth and productivity of cells in rotating culture. It was found increased growth and productivity occurred in simulated microgravity. Since this experiment involves growth of cells in a liquid medium, the fluidic effects must also be studied which is a limitation.

The economics of microgravity research.

Science.gov (United States)

DiFrancesco, Jeanne M; Olson, John M

2015-01-01

In this introduction to the economics of microgravity research, DiFrancesco and Olson explore the existing landscape and begin to define the requirements for a robust, well-funded microgravity research environment. This work chronicles the history, the opportunities, and how the decisions made today will shape the future. The past 60 years have seen tremendous growth in the capabilities and resources available to conduct microgravity science. However, we are now at an inflection point for the future of humanity in space. A confluence of factors including the rise of commercialization, a shifting funding landscape, and a growing international presence in space exploration, and terrestrial research platforms are shaping the conditions for full-scale microgravity research programs. In this first discussion, the authors focus on the concepts of markets, tangible and intangible value, research pathways and their implications for investments in research projects, and the collateral platforms needed. The opportunities and implications for adopting new approaches to funding and market-making illuminate how decisions made today will affect the speed of advances the community will be able to achieve in the future.

Studies of Two-Phase Gas-Liquid Flow in Microgravity. Ph.D. Thesis, Dec. 1994

Science.gov (United States)

Bousman, William Scott

1995-01-01

Two-phase gas-liquid flows are expected to occur in many future space operations. Due to a lack of buoyancy in the microgravity environment, two-phase flows are known to behave differently than those in earth gravity. Despite these concerns, little research has been conducted on microgravity two-phase flow and the current understanding is poor. This dissertation describes an experimental and modeling study of the characteristics of two-phase flows in microgravity. An experiment was operated onboard NASA aircraft capable of producing short periods of microgravity. In addition to high speed photographs of the flows, electronic measurements of void fraction, liquid film thickness, bubble and wave velocity, pressure drop and wall shear stress were made for a wide range of liquid and gas flow rates. The effects of liquid viscosity, surface tension and tube diameter on the behavior of these flows were also assessed. From the data collected, maps showing the occurrence of various flow patterns as a function of gas and liquid flow rates were constructed. Earth gravity two-phase flow models were compared to the results of the microgravity experiments and in some cases modified. Models were developed to predict the transitions on the flow pattern maps. Three flow patterns, bubble, slug and annular flow, were observed in microgravity. These patterns were found to occur in distinct regions of the gas-liquid flow rate parameter space. The effect of liquid viscosity, surface tension and tube diameter on the location of the boundaries of these regions was small. Void fraction and Weber number transition criteria both produced reasonable transition models. Void fraction and bubble velocity for bubble and slug flows were found to be well described by the Drift-Flux model used to describe such flows in earth gravity. Pressure drop modeling by the homogeneous flow model was inconclusive for bubble and slug flows. Annular flows were found to be complex systems of ring-like waves and a

Activation of nuclear transcription factor-kappaB in mouse brain induced by a simulated microgravity environment

Science.gov (United States)

Wise, Kimberly C.; Manna, Sunil K.; Yamauchi, Keiko; Ramesh, Vani; Wilson, Bobby L.; Thomas, Renard L.; Sarkar, Shubhashish; Kulkarni, Anil D.; Pellis, Neil R.; Ramesh, Govindarajan T.

2005-01-01

Microgravity induces inflammatory responses and modulates immune functions that may increase oxidative stress. Exposure to a microgravity environment induces adverse neurological effects; however, there is little research exploring the etiology of these effects resulting from exposure to such an environment. It is also known that spaceflight is associated with increase in oxidative stress; however, this phenomenon has not been reproduced in land-based simulated microgravity models. In this study, an attempt has been made to show the induction of reactive oxygen species (ROS) in mice brain, using ground-based microgravity simulator. Increased ROS was observed in brain stem and frontal cortex with concomitant decrease in glutathione, on exposing mice to simulated microgravity for 7 d. Oxidative stress-induced activation of nuclear factor-kappaB was observed in all the regions of the brain. Moreover, mitogen-activated protein kinase kinase was phosphorylated equally in all regions of the brain exposed to simulated microgravity. These results suggest that exposure of brain to simulated microgravity can induce expression of certain transcription factors, and these have been earlier argued to be oxidative stress dependent.

Lung volumes during sustained microgravity on Spacelab SLS-1

Science.gov (United States)

Elliott, Ann R.; Prisk, G. Kim; Guy, Harold J. B.; West, John B.

1994-01-01

Gravity is known to influence the mechanical behavior of the lung and chest wall. However, the effect of sustained microgravity (microgravity) on lung volumes has not been reported. Pulmonary function tests were performed by four subjects before, during, and after 9 days of microgravity exposure. Ground measurements were made in standing and supine postures. Tests were performed using a bag-in-box-and-flowmeter system and a respiratory mass spectrometer. Measurements included functional residual capacity (FRC), expiratory reserve volume (ERV), residual volume (RV), inspiratory and expiratory vital capacities (IVC and EVC), and tidal volume (V9sub T)). Total lung capacity (TLC) was derived from the measured EVC and RV values. With preflight standing values as a comparison, FRC was significantly reduced by 15% (approximately 500 ml) in microgravity and 32% in the supine posture. ERV was reduced by 10 - 20% in microgravity and decreased by 64% in the supine posture. RV was significantly reduced by 18% (310 ml) in microgravity but did not significantly change in the supine posture compared with standing. IVC and EVC were slightly reduced during the first 24 h of microgravity but returned to 1-G standing values within 72 h of microgravity exposure. IVC and EVC in the supine posture were significantly reduced by 12% compared with standing. During microgravity, V(sub T) decreased by 15% (approximately 90 ml), but supine V(sub T) was unchanged compared with preflight standing values. TLC decreased by approximately 8% during microgravity and in the supine posture compared with preflight standing. The reductions in FRC, ERV, and RV during microgravity are probably due to the cranial shift of the diaphragm, an increase in intrathoracic blood volume, and more uniform alveolar expansion.

An Update to Space Biomedical Research: Tissue Engineering in Microgravity Bioreactors

Directory of Open Access Journals (Sweden)

Abolfazl Barzegari

2012-03-01

Full Text Available Introduction: The severe need for constructing replacement tissues in organ transplantation has necessitated the development of tissue engineering approaches and bioreactors that can bring these approaches to reality. The inherent limitations of conventional bioreactors in generating realistic tissue constructs led to the devise of the microgravity tissue engineering that uses Rotating Wall Vessel (RWV bioreactors initially developed by NASA. Methods: In this review article, we intend to highlight some major advances and accomplishments in the rapidly-growing field of tissue engineering that could not be achieved without using microgravity. Results: Research is now focused on assembly of 3 dimensional (3D tissue fragments from various cell types in human body such as chondrocytes, osteoblasts, embryonic and mesenchymal stem cells, hepatocytes and pancreas islet cells. Hepatocytes cultured under microgravity are now being used in extracorporeal bioartificial liver devices. Tissue constructs can be used not only in organ replacement therapy, but also in pharmaco-toxicology and food safety assessment. 3D models of various cancers may be used in studying cancer development and biology or in high-throughput screening of anticancer drug candidates. Finally, 3D heterogeneous assemblies from cancer/immune cells provide models for immunotherapy of cancer. Conclusion: Tissue engineering in (simulated microgravity has been one of the stunning impacts of space research on biomedical sciences and their applications on earth.

Microgravity: A Teacher's Guide with Activities in Science, Mathematics, and Technology

Science.gov (United States)

Rogers, Melissa J.B.; Vogt, Gregory L.; Wargo, Michael J.

1997-01-01

Microgravity is the subject of this teacher's guide. This publication identifies the underlying mathematics, physics, and technology principles that apply to microgravity. The topics included in this publication are: 1) Microgravity Science Primer; 2) The Microgravity Environment of Orbiting Spacecraft; 3) Biotechnology; 4) Combustion Science; 5) Fluid Physics; 6) Fundamental Physics; and 7) Materials Science; 8) Microgravity Research and Exploration; and 9) Microgravity Science Space Flights. This publication also contains a glossary of selected terms.

Cell Culture in Microgravity: Opening the Door to Space Cell Biology

Science.gov (United States)

Pellis, Neal R.; Dawson, David L. (Technical Monitor)

1999-01-01

Adaptational response of human cell populations to microgravity is investigated using simulation, short-term Shuttle experiments, and long-term microgravity. Simulation consists of a clinostatically-rotated cell culture system. The system is a horizontally-rotated cylinder completely filled with culture medium. Low speed rotation results in continuous-fall of the cells through the fluid medium. In this setting, cells: 1) aggregate, 2) propagate in three dimensions, 3) synthesize matrix, 4) differentiate, and 5) form sinusoids that facilitate mass transfer. Space cell culture is conducted in flight bioreactors and in static incubators. Cells grown in microgravity are: bovine cartilage, promyelocytic leukemia, kidney proximal tubule cells, adrenal medulla, breast and colon cancer, and endothelium. Cells were cultured in space to test specific hypotheses. Cartilage cells were used to determine structural differences in cartilage grown in space compared to ground-based bioreactors. Results from a 130-day experiment on Mir revealed that cartilage grown in space was substantially more compressible due to insufficient glycosaminoglycan in the matrix. Interestingly, earth-grown cartilage conformed better to the dimensions of the scaffolding material, while the Mir specimens were spherical. The other cell populations are currently being analyzed for cell surface properties, gene expression, and differentiation. Results suggest that some cells spontaneously differentiate in microgravity. Additionally, vast changes in gene expression may occur in response to microgravity. In conclusion, the transition to microgravity may constitute a physical perturbation in cells resulting in unique gene expressions, the consequences of which may be useful in tissue engineering, disease modeling, and space cell biology.

Gene expression profiling of human peripheral blood lymphocytes cultured in modeled microgravity

Data.gov (United States)

National Aeronautics and Space Administration — In the present study we analyzed miRNA and mRNA expression profiles in human peripheral blood lymphocytes (PBLs) incubated in microgravity condition simulated by a...

DISTILLER: a data integration framework to reveal condition dependency of complex regulons in Escherichia coli.

Science.gov (United States)

Lemmens, Karen; De Bie, Tijl; Dhollander, Thomas; De Keersmaecker, Sigrid C; Thijs, Inge M; Schoofs, Geert; De Weerdt, Ami; De Moor, Bart; Vanderleyden, Jos; Collado-Vides, Julio; Engelen, Kristof; Marchal, Kathleen

2009-01-01

We present DISTILLER, a data integration framework for the inference of transcriptional module networks. Experimental validation of predicted targets for the well-studied fumarate nitrate reductase regulator showed the effectiveness of our approach in Escherichia coli. In addition, the condition dependency and modularity of the inferred transcriptional network was studied. Surprisingly, the level of regulatory complexity seemed lower than that which would be expected from RegulonDB, indicating that complex regulatory programs tend to decrease the degree of modularity.

The Effect of Microgravity on the Smallest Space Travelers: Bacterial Physiology and Virulence on Earth and in Microgravity

Science.gov (United States)

Pyle, Barry; Vasques, Marilyn; Aquilina, Rudy (Technical Monitor)

2002-01-01

Since the first human flights outside of Earth's gravity, crew health and well-being have been major concerns. Exposure to microgravity during spaceflight is known to affect the human immune response, possibly making the crew members more vulnerable to infectious disease. In addition, biological experiments previously flown in space have shown that bacteria grow faster in microgravity than they do on Earth. The ability of certain antibiotics to control bacterial infections may also differ greatly in microgravity. It is therefore critical to understand how spaceflight and microgravity affect bacterial virulence, which is their ability to cause disease. By utilizing spaceflight hardware provided by the European Space Agency (ESA), Dr. Barry Pyle and his team at Montana State University, Bozeman, will be performing an experiment to study the effects of microgravity on the virulence of a common soil and water bacterium, Pseudomonas aeruginosa. Importantly, these bacteria have been detected in the water supplies of previous Space Shuttle flights. The experiment will examine the effects of microgravity exposure on bacterial growth and on the bacterium's ability to form a toxin called Exotoxin A. Another goal is to evaluate the effects of microgravity on the physiology of the bacteria by analyzing their ability to respire (produce energy), by studying the condition of the plasma membrane surrounding the cell, and by determining if specific enzymes remain active. Proteins produced by the bacteria will also be assayed to see if the normal functions of the bacteria are affected. In the context of human life support in spaceflight, the results of this experiment will offer guidance in providing the highest possible water quality for the Shuttle in order to limit the risk of infection to human occupants and to minimize water system and spacecraft deterioration.

The time course of altered brain activity during 7-day simulated microgravity

Directory of Open Access Journals (Sweden)

Yang eLiao

2015-05-01

Full Text Available Microgravity causes multiple changes in physical and mental levels in humans, which can induce performance deficiency among astronauts. Studying the variations in brain activity that occur during microgravity would help astronauts to deal with these changes. In the current study, resting-state functional magnetic resonance imaging (rs-fMRI was used to observe the variations in brain activity during a 7-day head down tilt (HDT bed rest, which is a common and reliable model for simulated microgravity. The amplitudes of low frequency fluctuation (ALFF of twenty subjects were recorded pre-head down tilt (pre-HDT, during a bed rest period (HDT0, and then each day in the HDT period (HDT1–HDT7. One-way analysis of variance of the ALFF values over these 8 days was used to test the variation across time period (P＜0.05, corrected. Compared to HDT0, subjects presented lower ALFF values in the posterior cingulate cortex and higher ALFF values in the anterior cingulate cortex during the HDT period, which may partially account for the lack of cognitive flexibility and alterations in autonomic nervous system seen among astronauts in microgravity. Additionally, the observed improvement in function in CPL during the HDT period may play a compensatory role to the functional decline in the paracentral lobule to sustain normal levels of fine motor control for astronauts in a microgravity environment. Above all, those floating brain activities during 7 days of simulated microgravity may indicate that the brain self-adapts to help astronauts adjust to the multiple negative stressors encountered in a microgravity environment.

Response of Human Prostate Cancer Cells to Mitoxantrone Treatment in Simulated Microgravity Environment

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Zhang, Ye; Edwards, Christopher; Wu, Honglu

2011-01-01

This study explores the changes in growth of human prostate cancer cells (LNCaP) and their response to the treatment of antineoplastic agent, mitoxantrone, under the simulated microgravity condition. In comparison to static 1g, microgravity and simulated microgravity have been shown to alter global gene expression patterns and protein levels in various cultured cell models or animals. However, very little is known about the effect of altered gravity on the responses of cells to drugs, especially chemotherapy drugs. To test the hypothesis that zero gravity would result in altered regulation of cells in response to antineoplastic agents, we cultured LNCaP cells for 96 hr either in a High Aspect Ratio Vessel (HARV) bioreactor at the rotating condition to model microgravity in space or in the static condition as a control. 24 hr after the culture started, mitoxantrone was introduced to the cells at a final concentration of 1 M. The mitoxantrone treatment lasted 72 hr and then the cells were collected for various measurements. Compared to static 1g controls, the cells cultured in the simulated microgravity environment did not show significant differences in cell viability, growth rate, or cell cycle distribution. However, in response to mitoxantrone (1uM), a significant proportion of bioreactor cultured cells (30%) was arrested at G2 phase and a significant number of these cells were apoptotic in comparison to their static controls. The expressions of 84 oxidative stress related genes were analyzed using Qiagen PCR array to identify the possible mechanism underlying the altered responses of bioreactor culture cells to mitoxantrone. Nine out of 84 genes showed higher expression at four hour post mitoxantrone treatment in cells cultured at rotating condition compared to those at static. Taken together, the results reported here indicate that simulated microgravity may alter the responses of LNCaP cells to mitoxantrone treatment. The alteration of oxidative stress pathways

Glucocorticoid: A potential role in microgravity-induced bone loss

Science.gov (United States)

Yang, Jiancheng; Yang, Zhouqi; Li, Wenbin; Xue, Yanru; Xu, Huiyun; Li, Jingbao; Shang, Peng

2017-11-01

Exposure of animals and humans to conditions of microgravity, including actual spaceflight and simulated microgravity, results in numerous negative alterations to bone structure and mechanical properties. Although there are abundant researches on bone loss in microgravity, the explicit mechanism is not completely understood. At present, it is widely accepted that the absence of mechanical stimulus plays a predominant role in bone homeostasis disorders in conditions of weightlessness. However, aside from mechanical unloading, nonmechanical factors such as various hormones, cytokines, dietary nutrition, etc. are important as well in microgravity induced bone loss. The stress-induced increase in endogenous glucocorticoid (GC) levels is inevitable in microgravity environments. Moreover, it is well known that GCs have a detrimental effect to bone health at excess concentrations. Therefore, GC plays a potential role in microgravity-induced bone loss. This review summarizeds several studies and their prospective solutions to this hypothesis.

Determination of Roles of Microgravity and Ionizing Radiation on the Reactivation of Epstein-Barr Virus In Vitro

Science.gov (United States)

Mehta, Satish K; Renner, Ashlie; Stowe, Raymond; Bloom, David; Pierson, Duane

2015-01-01

Astronauts experience symptomatic and asymptomatic herpes virus reactivation during spaceflight. We have shown increases in reactivation of Epstein-Barr virus (EBV), cytomegalovirus (CMV) and varicella zoster virus (VZV) and shedding in body fluids (saliva and urine) in astronauts during space travel. Alterations in immunity, increased stress hormone levels, microgravity, increased radiation, and other conditions unique to spaceflight may promote reactivation of latent herpes viruses. Unique mechanico-physico forces associated with spaceflight can have profound effects on cellular function, especially immune cells. In space flight analog studies such as Antarctica, bed rest studies, and NASA's undersea habitat (Aquarius), reactivation of these viruses occurred, but to a lesser extent than spaceflight. Spaceflight analogs model some spaceflight factors, but none of the analogs recreates all factors experienced in space. Most notably, microgravity and radiation are not included in many analogs. Stress, processed through the HPA axis and SAM systems, induces viral reactivation. However, the respective roles of microgravity and increased space radiation levels or if any synergy exists are not known. Therefore, we studied the effect of modeled space radiation and/or microgravity, independent of the immune system on the changes in cellular gene expression that results in viral (EBV) reactivation. The effects of modeled microgravity and low shear on EBV replication and cellular and EBV gene expression were studied in human B-lymphocyte cell cultures. Latently infected B-lymphocytes were propagated in the rotating wall bioreactor and irradiated with the various dosages of gamma irradiation. At specific time intervals following exposure to modeled microgravity, the cells and supernatant were harvested and reactivation of EBV were assessed by measuring EBV and gene expression, DNA methylation, and infectious virus production.

The Low Temperature Microgravity Physics Facility Project

Science.gov (United States)

Chui, T.; Holmes, W.; Lai, A.; Croonquist, A.; Eraker, J.; Abbott, R.; Mills, G.; Mohl, J.; Craig, J.; Balachandra, B.;

Neurology of microgravity and space travel

Science.gov (United States)

Fujii, M. D.; Patten, B. M.

1992-01-01

Exposure to microgravity and space travel produce several neurologic changes, including SAS, ataxia, postural disturbances, perceptual illusions, neuromuscular weakness, and fatigue. Inflight SAS, perceptual illusions, and ocular changes are of more importance. After landing, however, ataxia, perceptual illusions, neuromuscular weakness, and fatigue play greater roles in astronaut health and readaptation to a terrestrial environment. Cardiovascular adjustments to microgravity, bone demineralization, and possible decompression sickness and excessive radiation exposure contribute further to medical problems of astronauts in space. A better understanding of the mechanisms by which microgravity adversely affects the nervous system and more effective treatments will provide healthier, happier, and longer stays in space on the space station Freedom and during the mission to Mars.

Computational analysis of LexA regulons in Cyanobacteria

Directory of Open Access Journals (Sweden)

Su Zhengchang

2010-09-01

Full Text Available Abstract Background The transcription factor LexA plays an important role in the SOS response in Escherichia coli and many other bacterial species studied. Although the lexA gene is encoded in almost every bacterial group with a wide range of evolutionary distances, its precise functions in each group/species are largely unknown. More recently, it has been shown that lexA genes in two cyanobacterial genomes Nostoc sp. PCC 7120 and Synechocystis sp. PCC 6803 might have distinct functions other than the regulation of the SOS response. To gain a general understanding of the functions of LexA and its evolution in cyanobacteria, we conducted the current study. Results Our analysis indicates that six of 33 sequenced cyanobacterial genomes do not harbor a lexA gene although they all encode the key SOS response genes, suggesting that LexA is not an indispensable transcription factor in these cyanobacteria, and that their SOS responses might be regulated by different mechanisms. Our phylogenetic analysis suggests that lexA was lost during the course of evolution in these six cyanobacterial genomes. For the 26 cyanobacterial genomes that encode a lexA gene, we have predicted their LexA-binding sites and regulons using an efficient binding site/regulon prediction algorithm that we developed previously. Our results show that LexA in most of these 26 genomes might still function as the transcriptional regulator of the SOS response genes as seen in E. coli and other organisms. Interestingly, putative LexA-binding sites were also found in some genomes for some key genes involved in a variety of other biological processes including photosynthesis, drug resistance, etc., suggesting that there is crosstalk between the SOS response and these biological processes. In particular, LexA in both Synechocystis sp. PCC6803 and Gloeobacter violaceus PCC7421 has largely diverged from those in other cyanobacteria in the sequence level. It is likely that LexA is no longer a

Fluid Physics and Macromolecular Crystal Growth in Microgravity

Science.gov (United States)

Helliwell, John R.; Snell, Edward H.; Chayen, Naomi E.; Judge, Russell A.; Boggon, Titus J.; Pusey, M. L.; Rose, M. Franklin (Technical Monitor)

2000-01-01

The first protein crystallization experiment in microgravity was launched in April, 1981 and used Germany's Technologische Experimente unter Schwerelosigkeit (TEXUS 3) sounding rocket. The protein P-galactosidase (molecular weight 465Kda) was chosen as the sample with a liquid-liquid diffusion growth method. A sliding device brought the protein, buffer and salt solution into contact when microgravity was reached. The sounding rocket gave six minutes of microgravity time with a cine camera and schlieren optics used to monitor the experiment, a single growth cell. In microgravity a strictly laminar diffusion process was observed in contrast to the turbulent convection seen on the ground. Several single crystals, approx 100micron in length, were formed in the flight which were of inferior but of comparable visual quality to those grown on the ground over several days. A second experiment using the same protocol but with solutions cooled to -8C (kept liquid with glycerol antifreeze) again showed laminar diffusion. The science of macromolecular structural crystallography involves crystallization of the macromolecule followed by use of the crystal for X-ray diffraction experiments to determine the three dimensional structure of the macromolecule. Neutron protein crystallography is employed for elucidation of H/D exchange and for improved definition of the bound solvent (D20). The structural information enables an understanding of how the molecule functions with important potential for rational drug design, improved efficiency of industrial enzymes and agricultural chemical development. The removal of turbulent convection and sedimentation in microgravity, and the assumption that higher quality crystals will be produced, has given rise to the growing number of crystallization experiments now flown. Many experiments can be flown in a small volume with simple, largely automated, equipment - an ideal combination for a microgravity experiment. The term "protein crystal growth

Free and membrane-bound calcium in microgravity and microgravity effects at the membrane level

Science.gov (United States)

Belyavskaya, N. A.

The changes of [Ca^2+]_i controlled is known to play a key regulatory role in numerous cellular processes especially associated with membranes. Previous studies from our laboratory have demonstrated an increase in calcium level in root cells of pea seedlings grown aboard orbital station ``Salyut 6'' /1/. These results: 1) indicate that observed Ca^2+-binding sites of membranes also consist in proteins and phospholipids; 2) suggest that such effects of space flight in membrane Ca-binding might be due to the enhancement of Ca^2+ influx through membranes. In model presented, I propose that Ca^2+-activated channels in plasma membrane in response to microgravity allow the movement of Ca^2+ into the root cells, causing a rise in cytoplasmic free Ca^2+ levels. The latter, in its turn, may induce the inhibition of a Ca^2+ efflux by Ca^2+-activated ATPases and through a Ca^2+/H^+ antiport. It is possible that increased cytosolic levels of Ca^2+ ions have stimulated hydrolysis and turnover of phosphatidylinositols, with a consequent elevation of cytosolic [Ca^2+]_i. Plant cell can response to such a Ca^2+ rise by an enhancement of membranous Ca^2+-binding activities to rescue thus a cell from an abundance of a cytotoxin. A Ca^2+-induced phase separation of membranous lipids assists to appear the structure nonstable zones with high energy level at the boundary of microdomains which are rich by some phospholipid components; there is mixing of molecules of the membranes contacted in these zones, the first stage of membranous fusion, which was found in plants exposed to microgravity. These results support the hypothesis that a target for microgravity effect is the flux mechanism of Ca^2+ to plant cell.

Proceedings of the Twentieth International Microgravity Measurements Group Meeting

Science.gov (United States)

DeLombard, Richard (Compiler)

2001-01-01

The International Microgravity Measurements Group annual meetings provide a forum for an exchange of information and ideas about various aspects of microgravity acceleration research in international microgravity research programs. These meetings are sponsored by the PI Microgravity Services (PIMS) project at the NASA Glenn Research Center. The twentieth MGMG meeting was held 7-9 August 2001 at the Hilton Garden Inn Hotel in Cleveland, Ohio. The 35 attendees represented NASA, other space agencies, universities, and commercial companies; eight of the attendees were international representatives from Canada, Germany, Italy, Japan, and Russia. Seventeen presentations were made on a variety of microgravity environment topics including the International Space Station (ISS), acceleration measurement and analysis results, science effects from microgravity accelerations, vibration isolation, free flyer satellites, ground testing, and microgravity outreach. Two working sessions were included in which a demonstration of ISS acceleration data processing and analyses were performed with audience participation. Contained within the minutes is the conference agenda which indicates each speaker, the title of their presentation, and the actual time of their presentation. The minutes also include the charts for each presentation which indicate the author's name(s) and affiliation. In some cases, a separate written report was submitted and has been included here.

Genome-Scale Co-Expression Network Comparison across Escherichia coli and Salmonella enterica Serovar Typhimurium Reveals Significant Conservation at the Regulon Level of Local Regulators Despite Their Dissimilar Lifestyles

Science.gov (United States)

Zarrineh, Peyman; Sánchez-Rodríguez, Aminael; Hosseinkhan, Nazanin; Narimani, Zahra; Marchal, Kathleen; Masoudi-Nejad, Ali

2014-01-01

Availability of genome-wide gene expression datasets provides the opportunity to study gene expression across different organisms under a plethora of experimental conditions. In our previous work, we developed an algorithm called COMODO (COnserved MODules across Organisms) that identifies conserved expression modules between two species. In the present study, we expanded COMODO to detect the co-expression conservation across three organisms by adapting the statistics behind it. We applied COMODO to study expression conservation/divergence between Escherichia coli, Salmonella enterica, and Bacillus subtilis. We observed that some parts of the regulatory interaction networks were conserved between E. coli and S. enterica especially in the regulon of local regulators. However, such conservation was not observed between the regulatory interaction networks of B. subtilis and the two other species. We found co-expression conservation on a number of genes involved in quorum sensing, but almost no conservation for genes involved in pathogenicity across E. coli and S. enterica which could partially explain their different lifestyles. We concluded that despite their different lifestyles, no significant rewiring have occurred at the level of local regulons involved for instance, and notable conservation can be detected in signaling pathways and stress sensing in the phylogenetically close species S. enterica and E. coli. Moreover, conservation of local regulons seems to depend on the evolutionary time of divergence across species disappearing at larger distances as shown by the comparison with B. subtilis. Global regulons follow a different trend and show major rewiring even at the limited evolutionary distance that separates E. coli and S. enterica. PMID:25101984

Microgravity Materials Science Conference 2000. Volume 1

Science.gov (United States)

Ramachandran, Narayanan (Editor); Bennett, Nancy (Editor); McCauley, Dannah (Editor); Murphy, Karen (Editor); Poindexter, Samantha (Editor)

2001-01-01

This is Volume 1 of 3 of the 2000 Microgravity Material Science Conference that was held June 6-8 at the Von Braun Center, Huntsville, Alabama. It was organized by the Microgravity Materials Science Discipline Working Group, sponsored by the Microgravity Research Division (MRD) at NASA Headquarters, and hosted by NASA Marshall Space Flight Center and the Alliance for Microgravity Materials Science and Applications (AMMSA). It was the fourth NASA conference of this type in the microgravity materials science discipline. The microgravity science program sponsored approx. 200 investigators, all of whom made oral or poster presentations at this conference. In addition, posters and exhibits covering NASA microgravity facilities, advanced technology development projects sponsored by the NASA Microgravity Research Division at NASA Headquarters, and commercial interests were exhibited. The purpose of the conference was to inform the materials science community of research opportunities in reduced gravity and to highlight the Spring 2001 release of the NASA Research Announcement (NRA) to solicit proposals for future investigations. It also served to review the current research and activities in materials science, to discuss the envisioned long-term goals. and to highlight new crosscutting research areas of particular interest to MRD. The conference was aimed at materials science researchers from academia, industry, and government. A workshop on in situ resource utilization (ISRU) was held in conjunction with the conference with the goal of evaluating and prioritizing processing issues in Lunar and Martian type environments. The workshop participation included invited speakers and investigators currently funded in the material science program under the Human Exploration and Development of Space (HEDS) initiative. The conference featured a plenary session every day with an invited speaker that was followed by three parallel breakout sessions in subdisciplines. Attendance was

Microgravity Materials Science Conference 2000. Volume 3

Science.gov (United States)

Ramachandran, Narayanan; Bennett, Nancy; McCauley, Dannah; Murphy, Karen; Poindexter, Samantha

2001-01-01

This is Volume 3 of 3 of the 2000 Microgravity Materials Science Conference that was held June 6-8 at the Von Braun Center, Huntsville, Alabama. It was organized by the Microgravity Materials Science Discipline Working Group, sponsored by the Microgravity Research Division (MRD) at NASA Headquarters, and hosted by NASA Marshall Space Flight Center and the Alliance for Microgravity Materials Science and Applications (AMMSA). It was the fourth NASA conference of this type in the Microgravity materials science discipline. The microgravity science program sponsored 200 investigators, all of whom made oral or poster presentations at this conference- In addition, posters and exhibits covering NASA microgravity facilities, advanced technology development projects sponsored by the NASA Microgravity Research Division at NASA Headquarters, and commercial interests were exhibited. The purpose of the conference was to inform the materials science community of research opportunities in reduced gravity and to highlight the Spring 2001 release of the NASA Research Announcement (NRA) to solicit proposals for future investigations. It also served to review the current research and activities in material,, science, to discuss the envisioned long-term goals. and to highlight new crosscutting research areas of particular interest to MRD. The conference was aimed at materials science researchers from academia, industry, and government. A workshop on in situ resource utilization (ISRU) was held in conjunction with the conference with the goal of evaluating and prioritizing processing issues in Lunar and Martian type environments. The workshop participation included invited speakers and investigators currently funded in the material science program under the Human Exploration and Development of Space (HEDS) initiative. The conference featured a plenary session every day with an invited speaker that was followed by three parallel breakout sessions in subdisciplines. Attendance was close

Microgravity Materials Science Conference 2000. Volume 2

Science.gov (United States)

Ramachandran, Narayanan (Editor); Bennett, Nancy (Editor); McCauley, Dannah (Editor); Murphy, Karen (Editor); Poindexter, Samantha (Editor)

2001-01-01

This is Volume 2 of 3 of the 2000 Microgravity Materials Science Conference that was held June 6-8 at the Von Braun Center, Huntsville, Alabama. It was organized by the Microgravity Materials Science Discipline Working Group, sponsored by the Microgravity Research Division (MRD) at NASA Headquarters, and hosted by NASA Marshall Space Flight Center and the Alliance for Microgravity Materials Science and Applications (AMMSA). It was the fourth NASA conference of this type in the Microgravity materials science discipline. The microgravity science program sponsored approx. 200 investigators, all of whom made oral or poster presentations at this conference- In addition, posters and exhibits covering NASA microgravity facilities, advanced technology development projects sponsored by the NASA Microgravity Research Division at NASA Headquarters, and commercial interests were exhibited. The purpose of the conference %%,its to inform the materials science community of research opportunities in reduced gravity and to highlight the Spring 2001 release of the NASA Research Announcement (NRA) to solicit proposals for future investigations. It also served to review the current research and activities in material,, science, to discuss the envisioned long-term goals. and to highlight new crosscutting research areas of particular interest to MRD. The conference was aimed at materials science researchers from academia, industry, and government. A workshop on in situ resource utilization (ISRU) was held in conjunction with the conference with the goal of evaluating and prioritizing processing issues in Lunar and Martian type environments. The workshop participation included invited speakers and investigators currently funded in the material science program under the Human Exploration and Development of Space (HEDS) initiative. The conference featured a plenary session every day with an invited speaker that was followed by three parallel breakout sessions in subdisciplines. Attendance

Solidification under microgravity

Indian Academy of Sciences (India)

Unknown

microgravity are highlighted in terms of science returns. Keywords. ... indicate its relevance in any materials science research programme, especially ..... of low gravity on the macro segregation patterns although good qualitative results were.

2002 Microgravity Materials Science Conference

Science.gov (United States)

Gillies, Donald (Editor); Ramachandran, Narayanan (Editor); Murphy, Karen (Editor); McCauley, Dannah (Editor); Bennett, Nancy (Editor)

2003-01-01

The 2002 Microgravity Materials Science Conference was held June 25-26, 2002, at the Von Braun Center, Huntsville, Alabama. Organized by the Microgravity Materials Science Discipline Working Group, sponsored by the Physical Sciences Research Division, NASA Headquarters, and hosted by NASA Marshall Space Flight Center and member institutions under the Cooperative Research in Biology and Materials Science (CORBAMS) agreement, the conference provided a forum to review the current research and activities in materials science, discuss the envisioned long-term goals, highlight new crosscutting research areas of particular interest to the Physical Sciences Research Division, and inform the materials science community of research opportunities in reduced gravity. An abstracts book was published and distributed at the conference to the approximately 240 people attending, who represented industry, academia, and other NASA Centers. This CD-ROM proceedings is comprised of the research reports submitted by the Principal Investigators in the Microgravity Materials Science program.

Fluid mechanics phenomena in microgravity; ASME Winter Annual Meeting, Anaheim, CA, Nov. 8-13, 1992

Science.gov (United States)

Siginer, Dennis A. (Editor); Weislogel, Mark M. (Editor)

1992-01-01

This paper is the first in a series of symposia presenting research activity in microgravity fluid mechanics. General topics addressed include two-phase flow and transport phenomena, thermo-capillary flow, and interfacial stability. Papers present mathmatical models of fluid dynamics in the microgravity environment. Applications suggested include space manufacturing and storage of liquids in low gravity.

Lung volumes during sustained microgravity on Spacelab SLS-1

Science.gov (United States)

Elliott, Ann R.; Prisk, Gordon Kim; Guy, Harold J. B.; West, John B.

1994-01-01

Gravity is known to influence the topographical gradients of pulmonary ventilation, perfusion, and pleural pressures. The effect of sustained microgravity on lung volumes has not previously been investigated. Pulmonary function tests were performed by four subjects before, during, and after 9 days of microgravity exposure. Ground measurements were made in standing and supine postures. Tests were performed using a bag-in-box and flowmeter system and a respiratory mass spectrometer. Measurements of tidal volume (V(sub T)), expiratory reserve volume (ERV), inspiratory and expiratory vital capacities (IVC, EVC), functional residual capacity (FRC), and residual volume (RV) were made. During microgravity, V(sub T) decreased by 15%. IVC and EVC were slightly reduced during the first 24 hrs of microgravity and returned to 1 g standing values within 72 hrs after the onset of microgravity. FRC was reduced by 15% and ERV decreased by 10-20%. RV was significantly reduced by 18%. The reductions in FRC, ERV, and V(sub T) during microgravity are probably due to the cranial shift of the diaphragm and an increase in intrathoracic blood volume.

microRNA expression profiles in human peripheral blood lymphocytes cultured in modeled microgravity

Data.gov (United States)

National Aeronautics and Space Administration — In the present study we analyzed miRNA and mRNA expression profiles in human peripheral blood lymphocytes (PBLs) incubated in microgravity condition simulated by a...

The adaptation of Escherichia coli cells grown in simulated microgravity for an extended period is both phenotypic and genomic.

Science.gov (United States)

Tirumalai, Madhan R; Karouia, Fathi; Tran, Quyen; Stepanov, Victor G; Bruce, Rebekah J; Ott, C Mark; Pierson, Duane L; Fox, George E

2017-01-01

Microorganisms impact spaceflight in a variety of ways. They play a positive role in biological systems, such as waste water treatment but can be problematic through buildups of biofilms that can affect advanced life support. Of special concern is the possibility that during extended missions, the microgravity environment will provide positive selection for undesirable genomic changes. Such changes could affect microbial antibiotic sensitivity and possibly pathogenicity. To evaluate this possibility, Escherichia coli (lac plus) cells were grown for over 1000 generations on Luria Broth medium under low-shear modeled microgravity conditions in a high aspect rotating vessel. This is the first study of its kind to grow bacteria for multiple generations over an extended period under low-shear modeled microgravity. Comparisons were made to a non-adaptive control strain using growth competitions. After 1000 generations, the final low-shear modeled microgravity-adapted strain readily outcompeted the unadapted lac minus strain. A portion of this advantage was maintained when the low-shear modeled microgravity strain was first grown in a shake flask environment for 10, 20, or 30 generations of growth. Genomic sequencing of the 1000 generation strain revealed 16 mutations. Of the five changes affecting codons, none were neutral. It is not clear how significant these mutations are as individual changes or as a group. It is concluded that part of the long-term adaptation to low-shear modeled microgravity is likely genomic. The strain was monitored for acquisition of antibiotic resistance by VITEK analysis throughout the adaptation period. Despite the evidence of genomic adaptation, resistance to a variety of antibiotics was never observed.

Bradyrhizobium elkanii nod regulon: insights through genomic analysis

Directory of Open Access Journals (Sweden)

Luciane M. P. Passaglia

2017-07-01

Full Text Available Abstract A successful symbiotic relationship between soybean [Glycine max (L. Merr.] and Bradyrhizobium species requires expression of the bacterial structural nod genes that encode for the synthesis of lipochitooligosaccharide nodulation signal molecules, known as Nod factors (NFs. Bradyrhizobium diazoefficiens USDA 110 possesses a wide nodulation gene repertoire that allows NF assembly and modification, with transcription of the nodYABCSUIJnolMNOnodZ operon depending upon specific activators, i.e., products of regulatory nod genes that are responsive to signaling molecules such as flavonoid compounds exuded by host plant roots. Central to this regulatory circuit of nod gene expression are NodD proteins, members of the LysR-type regulator family. In this study, publicly available Bradyrhizobium elkanii sequenced genomes were compared with the closely related B. diazoefficiens USDA 110 reference genome to determine the similarities between those genomes, especially with regards to the nod operon and nod regulon. Bioinformatics analyses revealed a correlation between functional mechanisms and key elements that play an essential role in the regulation of nod gene expression. These analyses also revealed new genomic features that had not been clearly explored before, some of which were unique for some B. elkanii genomes.

Lab-On-Chip Clinorotation System for Live-Cell Microscopy Under Simulated Microgravity

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Yew, Alvin G.; Atencia, Javier; Chinn, Ben; Hsieh, Adam H.

2013-01-01

Cells in microgravity are subject to mechanical unloading and changes to the surrounding chemical environment. How these factors jointly influence cellular function is not well understood. We can investigate their role using ground-based analogues to spaceflight, where mechanical unloading is simulated through the time-averaged nullification of gravity. The prevailing method for cellular microgravity simulation is to use fluid-filled containers called clinostats. However, conventional clinostats are not designed for temporally tracking cell response, nor are they able to establish dynamic fluid environments. To address these needs, we developed a Clinorotation Time-lapse Microscopy (CTM) system that accommodates lab-on- chip cell culture devices for visualizing time-dependent alterations to cellular behavior. For the purpose of demonstrating CTM, we present preliminary results showing time-dependent differences in cell area between human mesenchymal stem cells (hMSCs) under modeled microgravity and normal gravity.

Higher Plants in Space: Microgravity Perception, Response, and Adaptation

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Zheng, Hui Qiong; Han, Fei; Le, Jie

2015-11-01

Microgravity is a major abiotic stress in space. Its effects on plants may depend on the duration of exposure. We focused on two different phases of microgravity responses in space. When higher plants are exposed to short-term (seconds to hours) microgravity, such as on board parabolic flights and sounding rockets, their cells usually exhibit abiotic stress responses. For example, Ca 2+-, lipid-, and pH-signaling are rapidly enhanced, then the production of reactive oxygen species and other radicals increase dramatically along with changes in metabolism and auxin signaling. Under long-term (days to months) microgravity exposure, plants acclimatize to the stress by changing their metabolism and oxidative response and by enhancing other tropic responses. We conclude by suggesting that a systematic analysis of regulatory networks at the molecular level of higher plants is needed to understand the molecular signals in the distinct phases of the microgravity response and adaptation.

Numerical simulation of controlled directional solidification under microgravity conditions

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Holl, S.; Roos, D.; Wein, J.

The computer-assisted simulation of solidification processes influenced by gravity has gained increased importance during the previous years regarding ground-based as well as microgravity research. Depending on the specific needs of the investigator, the simulation model ideally covers a broad spectrum of applications. These primarily include the optimization of furnace design in interaction with selected process parameters to meet the desired crystallization conditions. Different approaches concerning the complexity of the simulation models as well as their dedicated applications will be discussed in this paper. Special emphasis will be put on the potential of software tools to increase the scientific quality and cost-efficiency of microgravity experimentation. The results gained so far in the context of TEXUS, FSLP, D-1 and D-2 (preparatory program) experiments, highlighting their simulation-supported preparation and evaluation will be discussed. An outlook will then be given on the possibilities to enhance the efficiency of pre-industrial research in the Columbus era through the incorporation of suitable simulation methods and tools.

Simulated Microgravity Modulates Differentiation Processes of Embryonic Stem Cells

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Vaibhav Shinde

2016-04-01

Full Text Available Background/Aims: Embryonic developmental studies under microgravity conditions in space are very limited. To study the effects of altered gravity on the embryonic development processes we established an in vitro methodology allowing differentiation of mouse embryonic stem cells (mESCs under simulated microgravity within a fast-rotating clinostat (clinorotation and capture of microarray-based gene signatures. Methods: The differentiating mESCs were cultured in a 2D pipette clinostat. The microarray and bioinformatics tools were used to capture genes that are deregulated by simulated microgravity and their impact on developmental biological processes. Results: The data analysis demonstrated that differentiation of mESCs in pipettes for 3 days resultet to early germ layer differentiation and then to the different somatic cell types after further 7 days of differentiation in the Petri dishes. Clinorotation influences differentiation as well as non-differentiation related biological processes like cytoskeleton related 19 genes were modulated. Notably, simulated microgravity deregulated genes Cyr61, Thbs1, Parva, Dhrs3, Jun, Tpm1, Fzd2 and Dll1 are involved in heart morphogenesis as an acute response on day 3. If the stem cells were further cultivated under normal gravity conditions (1 g after clinorotation, the expression of cardiomyocytes specific genes such as Tnnt2, Rbp4, Tnni1, Csrp3, Nppb and Mybpc3 on day 10 was inhibited. This correlated well with a decreasing beating activity of the 10-days old embryoid bodies (EBs. Finally, we captured Gadd45g, Jun, Thbs1, Cyr61and Dll1 genes whose expressions were modulated by simulated microgravity and by real microgravity in various reported studies. Simulated microgravity also deregulated genes belonging to the MAP kinase and focal dhesion signal transduction pathways. Conclusion: One of the most prominent biological processes affected by simulated microgravity was the process of cardiomyogenesis. The

Microgravity Emissions Laboratory (MEL)

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Federal Laboratory Consortium — The Microgravity Emissions Laboratory (MEL) utilizes a low-frequency acceleration measurement system for the characterization of rigid body inertial forces generated...

Ukrainian Program for Material Science in Microgravity

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Fedorov, Oleg

Ukrainian Program for Material Sciences in Microgravity O.P. Fedorov, Space Research Insti-tute of NASU -NSAU, Kyiv, The aim of the report is to present previous and current approach of Ukrainian research society to the prospect of material sciences in microgravity. This approach is based on analysis of Ukrainian program of research in microgravity, preparation of Russian -Ukrainian experiments on Russian segment of ISS and development of new Ukrainian strategy of space activity for the years 2010-2030. Two parts of issues are discussed: (i) the evolution of our views on the priorities in microgravity research (ii) current experiments under preparation and important ground-based results. item1 The concept of "space industrialization" and relevant efforts in Soviet and post -Soviet Ukrainian research institutions are reviewed. The main topics are: melt supercooling, crystal growing, testing of materials, electric welding and study of near-Earth environment. The anticipated and current results are compared. item 2. The main experiments in the framework of Ukrainian-Russian Research Program for Russian Segment of ISS are reviewed. Flight installations under development and ground-based results of the experiments on directional solidification, heat pipes, tribological testing, biocorrosion study is presented. Ground-based experiments and theoretical study of directional solidification of transparent alloys are reviewed as well as preparation of MORPHOS installation for study of succinonitrile -acetone in microgravity.

The Rcs regulon in Proteus mirabilis: implications for motility, biofilm formation, and virulence.

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Howery, Kristen E; Clemmer, Katy M; Rather, Philip N

2016-11-01

The overall role of the Rcs phosphorelay in Proteus mirabilis is largely unknown. Previous work had demonstrated that the Rcs phosphorelay represses the flhDC operon and activates the minCDE cell division inhibition system. To identify additional cellular functions regulated by the Rcs phosphorelay, an analysis of RNA-seq data was undertaken. In this report, the results of the RNA-sequencing are discussed with an emphasis on the predicted roles of the Rcs phosphorelay in swarmer cell differentiation, motility, biofilm formation, and virulence. RcsB is shown to activate genes important for differentiation and fimbriae formation, while repressing the expression of genes important for motility and virulence. Additionally, to follow up on the RNA-Seq data, we demonstrate that an rcsB mutant is deficient in its ability to form biofilm and exhibits enhanced virulence in a Galleria mellonella waxworm model. Overall, these results indicate the Rcs regulon in P. mirabilis extends beyond flagellar genes to include those involved in biofilm formation and virulence. Furthermore, the information presented in this study may provide clues to additional roles of the Rcs phosphorelay in other members of the Enterobacteriaceae.

Tissue Engineering Under Microgravity Conditions-Use of Stem Cells and Specialized Cells.

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Grimm, Daniela; Egli, Marcel; Krüger, Marcus; Riwaldt, Stefan; Corydon, Thomas J; Kopp, Sascha; Wehland, Markus; Wise, Petra; Infanger, Manfred; Mann, Vivek; Sundaresan, Alamelu

2018-03-29

Experimental cell research studying three-dimensional (3D) tissues in space and on Earth using new techniques to simulate microgravity is currently a hot topic in Gravitational Biology and Biomedicine. This review will focus on the current knowledge of the use of stem cells and specialized cells for tissue engineering under simulated microgravity conditions. We will report on recent advancements in the ability to construct 3D aggregates from various cell types using devices originally created to prepare for spaceflights such as the random positioning machine (RPM), the clinostat, or the NASA-developed rotating wall vessel (RWV) bioreactor, to engineer various tissues such as preliminary vessels, eye tissue, bone, cartilage, multicellular cancer spheroids, and others from different cells. In addition, stem cells had been investigated under microgravity for the purpose to engineer adipose tissue, cartilage, or bone. Recent publications have discussed different changes of stem cells when exposed to microgravity and the relevant pathways involved in these biological processes. Tissue engineering in microgravity is a new technique to produce organoids, spheroids, or tissues with and without scaffolds. These 3D aggregates can be used for drug testing studies or for coculture models. Multicellular tumor spheroids may be interesting for radiation experiments in the future and to reduce the need for in vivo experiments. Current achievements using cells from patients engineered on the RWV or on the RPM represent an important step in the advancement of techniques that may be applied in translational Regenerative Medicine.

Effect of a glucose impulse on the CcpA regulon in Staphylococcus aureus

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Engelmann Susanne

2009-05-01

Full Text Available Abstract Background The catabolite control protein A (CcpA is a member of the LacI/GalR family of transcriptional regulators controlling carbon-metabolism pathways in low-GC Gram-positive bacteria. It functions as a catabolite repressor or activator, allowing the bacteria to utilize the preferred carbon source over secondary carbon sources. This study is the first CcpA-dependent transcriptome and proteome analysis in Staphylococcus aureus, focussing on short-time effects of glucose under stable pH conditions. Results The addition of glucose to exponentially growing S. aureus increased the expression of genes and enzymes of the glycolytic pathway, while genes and proteins of the tricarboxylic acid (TCA cycle, required for the complete oxidation of glucose, were repressed via CcpA. Phosphotransacetylase and acetate kinase, converting acetyl-CoA to acetate with a concomitant substrate-level phosphorylation, were neither regulated by glucose nor by CcpA. CcpA directly repressed genes involved in utilization of amino acids as secondary carbon sources. Interestingly, the expression of a larger number of genes was found to be affected by ccpA inactivation in the absence of glucose than after glucose addition, suggesting that glucose-independent effects due to CcpA may have a particular impact in S. aureus. In the presence of glucose, CcpA was found to regulate the expression of genes involved in metabolism, but also that of genes coding for virulence determinants. Conclusion This study describes the CcpA regulon of exponentially growing S. aureus cells. As in other bacteria, CcpA of S. aureus seems to control a large regulon that comprises metabolic genes as well as virulence determinants that are affected in their expression by CcpA in a glucose-dependent as well as -independent manner.

The Influence of Microgravity on Silica Sol-Gel Formation

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Sibille, L.; Smith, D. D.; Cronise, R.; Hunt, A. J.; Wolfe, D. B.; Snow, L. A.; Oldenberg, S.; Halas, N.; Rose, M. Franklin (Technical Monitor)

2000-01-01

We discuss space-flight experiments involving the growth of silica particles and gels. The effect of microgravity on the growth of silica particles via the sol-gel route is profound. In four different recipes spanning a large range of the parameter space that typically produces silica nanoparticles in unit-gravity, low-density gel structures were instead formed in microgravity. The particles that did form were generally smaller and more polydisperse than those grown on the ground. These observations suggest that microgravity reduces the particle growth rate, allowing unincorporated species to form aggregates and ultimately gel. Hence microgravity favors the formation of more rarefied structures, providing a bias towards diffusion-limited cluster-cluster aggregation. These results further suggest that in unit gravity, fluid flows and sedimentation can significantly perturb sol-gel substructures prior to gelation and these deleterious perturbations may be "frozen" into the resulting microstructure. Hence, sol-gel pores may be expected to be smaller, more uniform, and less rough when formed in microgravity.

Hemodynamic effects of microgravity and their ground-based simulations

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Lobachik, V. I.; Abrosimov, S. V.; Zhidkov, V. V.; Endeka, D. K.

Hemodynamic effects of simulated microgravity were investigated, in various experiments, using radioactive isotopes, in which 40 healthy men, aged 35 to 42 years, took part. Blood shifts were evaluated qualitatively and quantitatively. Simulation studies included bedrest, head-down tilt (-5° and -15°), and vertical water immersion, it was found that none of the methods could entirely simulate hemodynamic effects of microgravity. Subjective sensations varied in a wide range. They cannot be used to identify reliably the effects of real and simulated microgravity. Renal fluid excretion in real and simulated microgravity was different in terms of volume and time. The experiments yielded data about the general pattern of circulation with blood displaced to the upper body.

Treatment of Radix Dipsaci extract prevents long bone loss induced by modeled microgravity in hindlimb unloading rats.

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Niu, Yinbo; Li, Chenrui; Pan, Yalei; Li, Yuhua; Kong, Xianghe; Wang, Shuo; Zhai, YuanKun; Wu, Xianglong; Fan, Wutu; Mei, Qibing

2015-01-01

Radix Dipsaci is a kidney tonifying herbal medicine with a long history of safe use for treatment of bone fractures and joint diseases in China. Previous studies have shown that Radix Dipsaci extract (RDE) could prevent bone loss in ovariectomized rats. This study investigates the effect of RDE against bone loss induced by simulated microgravity. A hindlimb unloading rat model was established to determine the effect of RDE on bone mineral density and bone microarchitecture. Twenty-four male Sprague-Dawley rats were divided into four groups (n = 6 per group): control (CON), hindlimb unloading with vehicle (HLU), hindlimb unloading treated with alendronate (HLU-ALN, 2.0 mg/kg/d), and hindlimb unloading treated with RDE (HLU-RDE, 500 mg/kg/d). RDE or ALN was administrated orally for 4 weeks. Treatment with RDE had a positive effect on mechanical strength, BMD, BMC, bone turnover markers, and the changes in urinary calcium and phosphorus excretion. MicroCT analysis showed that RDE significantly prevented the reduction of the bone volume fraction, connectivity density, trabecular number, thickness, tissue mineral density, and tissue mineral content as well as improved the trabecular separation and structure model index. RDE was demonstrated to prevent the loss of bone mass induced by HLU treatment, which suggests the potential application of RDE in the treatment of microgravity-induced bone loss.

Plant Cell Adaptive Responses to Microgravity

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Kordyum, Elizabeth; Kozeko, Liudmyla; Talalaev, Alexandr

Microgravity is an abnormal environmental condition that plays no role in the functioning of biosphere. Nevertheless, the chronic effect of microgravity in space flight as an unfamiliar factor does not prevent the development of adaptive reactions at the cellular level. In real microgravity in space flight under the more or less optimal conditions for plant growing, namely temperature, humidity, CO2, light intensity and directivity in the hardware angiosperm plants perform an “reproductive imperative”, i.e. they flower, fruit and yield viable seeds. It is known that cells of a multicellular organism not only take part on reactions of the organism but also carry out processes that maintain their integrity. In light of these principles, the problem of the identification of biochemical, physiological and structural patterns that can have adaptive significance at the cellular and subcellular level in real and simulated microgravity is considered. Cytological studies of plants developing in real and simulated microgravity made it possible to establish that the processes of mitosis, cytokinesis, and tissue differentiation of vegetative and generative organs are largely normal. At the same time, under microgravity, essential reconstruction in the structural and functional organization of cell organelles and cytoskeleton, as well as changes in cell metabolism and homeostasis have been described. In addition, new interesting data concerning the influence of altered gravity on lipid peroxidation intensity, the level of reactive oxygen species, and antioxidant system activity, just like on the level of gene expression and synthesis of low-molecular and high-molecular heat shock proteins were recently obtained. So, altered gravity caused time-dependent increasing of the HSP70 and HSP90 levels in cells, that may indicate temporary strengthening of their functional loads that is necessary for re-establish a new cellular homeostasis. Relative qPCR results showed that

Media Compositions for Three-Dimensional Mammalian Tissue Growth under Microgravity Culture Conditions

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Goodwin, Thomas J. (Inventor)

1998-01-01

Normal mammalian tissue and the culturing process has been developed for the three groups of organ, structural and blood tissue.The cells are grown in vitro under microgravity culture conditions and form three dimensional cells aggregates with normal cell function. The microgravity culture conditions may be microgravity or simulated microgravity created in a horizontal rotating wall culture vessel.

Media Compositions for Three Dimensional Mammalian Tissue Growth Under Microgravity Culture Conditions

Science.gov (United States)

Goodwin, Thomas J. (Inventor)

1998-01-01

Normal mammalian tissue and the culturing process has been developed for the three groups of organ, structural and blood tissue. The cells are grown in vitro under microgravity culture conditions and form three dimensional cells aggregates with normal cell function. The microgravity culture conditions may be microgravity or simulated microgravity created in a horizontal rotating wall culture vessel.

Global gene expression under nitrogen starvation in Xylella fastidiosa: contribution of the σ54 regulon

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da Silva Neto José F

2010-08-01

Full Text Available Abstract Background Xylella fastidiosa, a Gram-negative fastidious bacterium, grows in the xylem of several plants causing diseases such as citrus variegated chlorosis. As the xylem sap contains low concentrations of amino acids and other compounds, X. fastidiosa needs to cope with nitrogen limitation in its natural habitat. Results In this work, we performed a whole-genome microarray analysis of the X. fastidiosa nitrogen starvation response. A time course experiment (2, 8 and 12 hours of cultures grown in defined medium under nitrogen starvation revealed many differentially expressed genes, such as those related to transport, nitrogen assimilation, amino acid biosynthesis, transcriptional regulation, and many genes encoding hypothetical proteins. In addition, a decrease in the expression levels of many genes involved in carbon metabolism and energy generation pathways was also observed. Comparison of gene expression profiles between the wild type strain and the rpoN null mutant allowed the identification of genes directly or indirectly induced by nitrogen starvation in a σ54-dependent manner. A more complete picture of the σ54 regulon was achieved by combining the transcriptome data with an in silico search for potential σ54-dependent promoters, using a position weight matrix approach. One of these σ54-predicted binding sites, located upstream of the glnA gene (encoding glutamine synthetase, was validated by primer extension assays, confirming that this gene has a σ54-dependent promoter. Conclusions Together, these results show that nitrogen starvation causes intense changes in the X. fastidiosa transcriptome and some of these differentially expressed genes belong to the σ54 regulon.

Cavitation studies in microgravity

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Kobel, Philippe; Obreschkow, Danail; Farhat, Mohamed; Dorsaz, Nicolas; de Bosset, Aurele

. The aim of our future microgravity experiment is to assess the direct effects of gravity on cavitation bubble collapse through a comparison of single cavitation bubbles collapsing in mi-crogravity, normal gravity, and hypergravity. In particular, we shall investigate the shape of the bubble in its final collapse stage and the amount of energy dissipated in the dominant collapse channels, such as liquid jet, shock wave, and rebound bubble. The highly spherical bubbles will be produced via a point-like plasma generated by a high power laser beam. One major hypothesis that we will test is an increase in shock wave energy with decreasing gravity as a consequence of the higher final sphericity and suppression of liquid jets. To support this, we introduce an analytical model for the gravity-perturbed asymmetric collapse of spherical bubbles, and demonstrate that all initially spherical bubbles develop a gravity-related vertical jet along their collapse.

Streptococcus mutans NADH oxidase lies at the intersection of overlapping regulons controlled by oxygen and NAD+ levels.

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Baker, J L; Derr, A M; Karuppaiah, K; MacGilvray, M E; Kajfasz, J K; Faustoferri, R C; Rivera-Ramos, I; Bitoun, J P; Lemos, J A; Wen, Z T; Quivey, R G

2014-06-01

NADH oxidase (Nox, encoded by nox) is a flavin-containing enzyme used by the oral pathogen Streptococcus mutans to reduce diatomic oxygen to water while oxidizing NADH to NAD(+). The critical nature of Nox is 2-fold: it serves to regenerate NAD(+), a carbon cycle metabolite, and to reduce intracellular oxygen, preventing formation of destructive reactive oxygen species (ROS). As oxygen and NAD(+) have been shown to modulate the activity of the global transcription factors Spx and Rex, respectively, Nox is potentially poised at a critical junction of two stress regulons. In this study, microarray data showed that either addition of oxygen or loss of nox resulted in altered expression of genes involved in energy metabolism and transport and the upregulation of genes encoding ROS-metabolizing enzymes. Loss of nox also resulted in upregulation of several genes encoding transcription factors and signaling molecules, including the redox-sensing regulator gene rex. Characterization of the nox promoter revealed that nox was regulated by oxygen, through SpxA, and by Rex. These data suggest a regulatory loop in which the roles of nox in reduction of oxygen and regeneration of NAD(+) affect the activity levels of Spx and Rex, respectively, and their regulons, which control several genes, including nox, crucial to growth of S. mutans under conditions of oxidative stress. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Fluid behavior in microgravity environment

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Hung, R. J.; Lee, C. C.; Tsao, Y. D.

1990-01-01

The instability of liquid and gas interface can be induced by the presence of longitudinal and lateral accelerations, vehicle vibration, and rotational fields of spacecraft in a microgravity environment. In a spacecraft design, the requirements of settled propellant are different for tank pressurization, engine restart, venting, or propellent transfer. In this paper, the dynamical behavior of liquid propellant, fluid reorientation, and propellent resettling have been carried out through the execution of a CRAY X-MP super computer to simulate fluid management in a microgravity environment. Characteristics of slosh waves excited by the restoring force field of gravity jitters have also been investigated.

Myocardial CKIP-1 Overexpression Protects from Simulated Microgravity-Induced Cardiac Remodeling

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Shukuan Ling

2018-01-01

Full Text Available Human cardiovascular system has adapted to Earth's gravity of 1G. The microgravity during space flight can induce cardiac remodeling and decline of cardiac function. At present, the mechanism of cardiac remodeling induced by microgravity remains to be disclosed. Casein kinase-2 interacting protein-1 (CKIP-1 is an important inhibitor of pressure-overload induced cardiac remodeling by decreasing the phosphorylation level of HDAC4. However, the role of CKIP-1 in the cardiac remodeling induced by microgravity is unknown. The purpose of this study was to determine whether CKIP-1 was also involved in the regulation of cardiac remodeling induced by microgravity. We first detected the expression of CKIP-1 in the heart from mice and monkey after simulated microgravity using Q-PCR and western blotting. Then, myocardial specific CKIP-1 transgenic (TG and wild type mice were hindlimb-suspended (HU to simulate microgravity effect. We estimated the cardiac remodeling in morphology and function by histological analysis and echocardiography. Finally, we detected the phosphorylation of AMPK, ERK1/2, and HDAC4 in the heart from wild type and CKIP-1 transgenic mice after HU. The results revealed the reduced expression of CKIP-1 in the heart both from mice and monkey after simulated microgravity. Myocardial CKIP-1 overexpression protected from simulated microgravity-induced decline of cardiac function and loss of left ventricular mass. Histological analysis demonstrated CKIP-1 TG inhibited the decreases in the size of individual cardiomyocytes of mice after hindlimb unloading. CKIP-1 TG can inhibit the activation of HDAC4 and ERK1/2 and the inactivation of AMPK in heart of mice induced by simulated microgravity. These results demonstrated CKIP-1 was a suppressor of cardiac remodeling induced by simulated microgravity.

Combustion in microgravity: The French contribution

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Prud'homme, Roger; Legros, Guillaume; Torero, José L.

2017-01-01

Microgravity (drop towers, parabolic flights, sounding rockets and space stations) are particularly relevant to combustion problems given that they show high-density gradients and in many cases weak forced convection. For some configurations where buoyancy forces result in complex flow fields, microgravity leads to ideal conditions that correspond closely to canonical problems, e.g., combustion of a spherical droplet in a far-field still atmosphere, Emmons' problem for flame spreading over a solid flat plate, deflagration waves, etc. A comprehensive chronological review on the many combustion studies in microgravity was written first by Law and Faeth (1994) and then by F.A. Williams (1995). Later on, new recommendations for research directions have been delivered. In France, research has been managed and supported by CNES and CNRS since the creation of the microgravity research group in 1992. At this time, microgravity research and future activities contemplated the following: Droplets: the "D2 law" has been well verified and high-pressure behavior of droplet combustion has been assessed. The studies must be extended in two main directions: vaporization in mixtures near the critical line and collective effects in dense sprays. Flame spread: experiments observed blue flames governed by diffusion that are in accordance with Emmons' theory. Convection-dominated flames showed significant departures from the theory. Some theoretical assumptions appeared controversial and it was noted that radiation effects must be considered, especially when regarding the role of soot production in quenching. Heterogeneous flames: two studies are in progress, one in Poitiers and the other in Marseilles, about flame/suspension interactions. Premixed and triple flames: the knowledge still needs to be complemented. Triple flames must continue to be studied and understanding of "flame balls" still needs to be addressed.

Planarians Sense Simulated Microgravity and Hypergravity

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Teresa Adell

2014-01-01

Full Text Available Planarians are flatworms, which belong to the phylum Platyhelminthes. They have been a classical subject of study due to their amazing regenerative ability, which relies on the existence of adult totipotent stem cells. Nowadays they are an emerging model system in the field of developmental, regenerative, and stem cell biology. In this study we analyze the effect of a simulated microgravity and a hypergravity environment during the process of planarian regeneration and embryogenesis. We demonstrate that simulated microgravity by means of the random positioning machine (RPM set at a speed of 60 °/s but not at 10 °/s produces the dead of planarians. Under hypergravity of 3 g and 4 g in a large diameter centrifuge (LDC planarians can regenerate missing tissues, although a decrease in the proliferation rate is observed. Under 8 g hypergravity small planarian fragments are not able to regenerate. Moreover, we found an effect of gravity alterations in the rate of planarian scission, which is its asexual mode of reproduction. No apparent effects of altered gravity were found during the embryonic development.

Review of Environmental and Geological Microgravity Applications and Feasibility of Its Employment at Archaeological Sites in Israel

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Lev V. Eppelbaum

2011-01-01

Full Text Available Microgravity investigations are widely applied at present for solving various environmental and geological problems. Unfortunately, microgravity survey is comparatively rarely used for searching for hidden ancient targets. It is caused mainly by small geometric size of the desired archaeological objects and various types of noise complicating the observed useful signal. At the same time, development of modern generation of field gravimetric equipment allows to register promptly and digitally microGal (10-8 m/s2 anomalies that offer a new challenge in this direction. An advanced methodology of gravity anomalies analysis and modern 3D modeling, intended for ancient targets delineation, is briefly presented. It is supposed to apply in archaeological microgravity the developed original methods for the surrounding terrain relief computing. Calculating second and third derivatives of gravity potential are useful for revealing some closed peculiarities of the different Physical-Archaeological Models (PAMs. It is underlined that physical measurement of vertical gravity derivatives in archaeological studying has a significant importance and cannot be replaced by any transformation methods. Archaeological targets in Israel have been ranged by their density/geometrical characteristics in several groups. The performed model computations indicate that microgravity investigations might be successfully applied at least in 20–25% of archaeological sites in Israel.

RpfF-dependent regulon of Xylella fastidiosa.

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Wang, Nian; Li, Jian-Liang; Lindow, Steven E

2012-11-01

ABSTRACT Xylella fastidiosa regulates traits important to both virulence of grape as well as colonization of sharpshooter vectors via its production of a fatty acid signal molecule known as DSF whose production is dependent on rpfF. Although X. fastidiosa rpfF mutants exhibit increased virulence to plants, they are unable to be spread from plant to plant by insect vectors. To gain more insight into the traits that contribute to these processes, a whole-genome Agilent DNA microarray for this species was developed and used to determine the RpfF-dependent regulon by transcriptional profiling. In total, 446 protein coding genes whose expression was significantly different between the wild type and an rpfF mutant (false discovery rate genes were downregulated in the rpfF mutant compared with the wild-type strain whereas 281 genes were over-expressed. RpfF function was required for regulation of 11 regulatory and σ factors, including rpfE, yybA, PD1177, glnB, rpfG, PD0954, PD0199, PD2050, colR, rpoH, and rpoD. In general, RpfF is required for regulation of genes involved in attachment and biofilm formation, enhancing expression of hemagglutinin genes hxfA and hxfB, and suppressing most type IV pili and gum genes. A large number of other RpfF-dependent genes that might contribute to virulence or insect colonization were also identified such as those encoding hemolysin and colicin V, as well as genes with unknown functions.

The Influence of Microgravity on Plants

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Levine, Howard G.

2010-01-01

This slide presentation reviews the studies and the use of plants in various space exploration scenarios. The current state of research on plant growth in microgravity is reviewed, with several questions that require research for answers to assist in our fundamental understanding of the influence of microgravity and the space environment on plant growth. These questions are posed to future Principal Investigators and Payload Developers, attending the meeting, in part, to inform them of NASA's interest in proposals for research on the International Space Station.

Disrupted resting-state functional architecture of the brain after 45-day simulated microgravity

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Zhou, Yuan; Wang, Yun; Rao, Li-Lin; Liang, Zhu-Yuan; Chen, Xiao-Ping; Zheng, Dang; Tan, Cheng; Tian, Zhi-Qiang; Wang, Chun-Hui; Bai, Yan-Qiang; Chen, Shan-Guang; Li, Shu

2014-01-01

Long-term spaceflight induces both physiological and psychological changes in astronauts. To understand the neural mechanisms underlying these physiological and psychological changes, it is critical to investigate the effects of microgravity on the functional architecture of the brain. In this study, we used resting-state functional MRI (rs-fMRI) to study whether the functional architecture of the brain is altered after 45 days of −6° head-down tilt (HDT) bed rest, which is a reliable model for the simulation of microgravity. Sixteen healthy male volunteers underwent rs-fMRI scans before and after 45 days of −6° HDT bed rest. Specifically, we used a commonly employed graph-based measure of network organization, i.e., degree centrality (DC), to perform a full-brain exploration of the regions that were influenced by simulated microgravity. We subsequently examined the functional connectivities of these regions using a seed-based resting-state functional connectivity (RSFC) analysis. We found decreased DC in two regions, the left anterior insula (aINS) and the anterior part of the middle cingulate cortex (MCC; also called the dorsal anterior cingulate cortex in many studies), in the male volunteers after 45 days of −6° HDT bed rest. Furthermore, seed-based RSFC analyses revealed that a functional network anchored in the aINS and MCC was particularly influenced by simulated microgravity. These results provide evidence that simulated microgravity alters the resting-state functional architecture of the brains of males and suggest that the processing of salience information, which is primarily subserved by the aINS–MCC functional network, is particularly influenced by spaceflight. The current findings provide a new perspective for understanding the relationships between microgravity, cognitive function, autonomic neural function, and central neural activity. PMID:24926242

Disrutpted resting-state functional architecture of the brain after 45-day simulated microgravity

Directory of Open Access Journals (Sweden)

Yuan eZhou

2014-06-01

Full Text Available Long-term spaceflight induces both physiological and psychological changes in astronauts. To understand the neural mechanisms underlying these physiological and psychological changes, it is critical to investigate the effects of microgravity on the functional architecture of the brain. In this study, we used resting-state functional MRI (rs-fMRI to study whether the functional architecture of the brain is altered after 45 days of -6° head-down tilt (HDT bed rest, which is a reliable model for the simulation of microgravity. Sixteen healthy male volunteers underwent rs-fMRI scans before and after 45 days of -6° HDT bed rest. Specifically, we used a commonly employed graph-based measure of network organization, i.e., degree centrality (DC, to perform a full-brain exploration of the regions that were influenced by simulated microgravity. We subsequently examined the functional connectivities of these regions using a seed-based resting-state functional connectivity (RSFC analysis. We found decreased DC in two regions, the left anterior insula (aINS and the anterior part of the middle cingulate cortex (MCC; also called the dorsal anterior cingulate cortex in many studies, in the male volunteers after 45 days of -6° HDT bed rest. Furthermore, seed-based RSFC analyses revealed that a functional network anchored in the aINS and MCC was particularly influenced by simulated microgravity. These results provide evidence that simulated microgravity alters the resting-state functional architecture of the brains of males and suggest that the processing of salience information, which is primarily subserved by the aINS–MCC functional network, is particularly influenced by spaceflight. The current findings provide a new perspective for understanding the relationships between microgravity, cognitive function, autonomic neural function and central neural activity.

Industrialization of Space: Microgravity Based Opportunities for Material and Life Science

Science.gov (United States)

Cozmuta, Ioana; Harper, Lynn D.; Rasky, Daniel J.; MacDonald, Alexander; Pittman, Robert

2015-01-01

Microgravity based commercial opportunities are broad, with applications ranging from fiber optics, device-grade semiconductor crystals, space beads, new materials, cell micro encapsulation, 3D tissues and cell cultures, genetic and molecular changes of immune suppression, protein and virus crystal growth, perfume and hair care. To date, primarily the knowledge gained from observing and understanding new end states of systems unraveled in microgravity has been translated into unique technologies and business opportunities on Earth. In some instances existing light qualified hardware is immediately available for commercial RD for small scale in-space manufacturing. Overall products manufactured in microgravity have key properties usually surpassing the best terrestrial counterparts. The talk will address the potential benefits of microgravity research for a variety of terrestrial markets. Our findings originate from discussions with 100+ non-aerospace private companies among the high-tech Silicon Valley ecosystem, show that the opportunities and benefits of using the ISS are largely not considered by experts, primarily due to a lack of awareness of the breadth of terrestrial applications that have been enabled or enhanced by microgravity RD. Based on this dialogue, the concept of microgravity verticals is developed to translate the benefits of the microgravity environment into blue ocean business opportunities for various key US commercial sectors.

Characterization of the SOS meta-regulon in the human gut microbiome.

Science.gov (United States)

Cornish, Joseph P; Sanchez-Alberola, Neus; O'Neill, Patrick K; O'Keefe, Ronald; Gheba, Jameel; Erill, Ivan

2014-05-01

Data from metagenomics projects remain largely untapped for the analysis of transcriptional regulatory networks. Here, we provide proof-of-concept that metagenomic data can be effectively leveraged to analyze regulatory networks by characterizing the SOS meta-regulon in the human gut microbiome. We combine well-established in silico and in vitro techniques to mine the human gut microbiome data and determine the relative composition of the SOS network in a natural setting. Our analysis highlights the importance of translesion synthesis as a primary function of the SOS response. We predict the association of this network with three novel protein clusters involved in cell wall biogenesis, chromosome partitioning and restriction modification, and we confirm binding of the SOS response transcriptional repressor to sites in the promoter of a cell wall biogenesis enzyme, a phage integrase and a death-on-curing protein. We discuss the implications of these findings and the potential for this approach for metagenome analysis.

The potential impact of microgravity science and technology on education

Science.gov (United States)

Wargo, M. J.

1992-01-01

The development of educational support materials by NASA's Microgravity Science and Applications Division is discussed in the light of two programs. Descriptions of the inception and application possibilities are given for the Microgravity-Science Teacher's Guide and the program of Undergraduate Research Opportunities in Microgravity Science and Technology. The guide is intended to introduce students to the principles and research efforts related to microgravity, and the undergraduate program is intended to reinforce interest in the space program. The use of computers and electronic communications is shown to be an important catalyst for the educational efforts. It is suggested that student and teacher access to these programs be enhanced so that they can have a broader impact on the educational development of space-related knowledge.

Technology base for microgravity horticulture

Science.gov (United States)

Sauer, R. L.; Magnuson, J. W.; Scruby, R. R.; Scheld, H. W.

1987-01-01

Advanced microgravity plant biology research and life support system development for the spacecraft environment are critically hampered by the lack of a technology base. This inadequacy stems primarily from the fact that microgravity results in a lack of convective currents and phase separation as compared to the one gravity environment. A program plan is being initiated to develop this technology base. This program will provide an iterative flight development effort that will be closely integrated with both basic science investigations and advanced life support system development efforts incorporating biological processes. The critical considerations include optimum illumination methods, root aeration, root and shoot support, and heat rejection and gas exchange in the plant canopy.

Observations of Confinement of a Paramagnetic Liquid in Model Propellant Tanks in Microgravity by the Kelvin Force

Science.gov (United States)

Kuhlman, John; Gray, Donald D.; Barnard, Austin; Hazelton, Jennifer; Lechliter, Matthew; Starn, Andrew; Battleson, Charles; Glaspell, Shannon; Kreitzer, Paul; Leichliter, Michelle

2002-11-01

The magnetic Kelvin force has been proposed as an artificial gravity to control the orientation of paramagnetic liquid propellants such as liquid oxygen in a microgravity environment. This paper reports experiments performed in the NASA "Weightless Wonder" KC-135 aircraft, through the Reduced Gravity Student Flight Opportunities Program. The aircraft flies through a series of parabolic arcs providing about 25 s of microgravity in each arc. The experiment was conceived, designed, constructed, and performed by the undergraduate student team and their two faculty advisors. Two types of tanks were tested: square-base prismatic tanks 5 cm x 5 cm x 8.6 cm and circular cylinders 5 cm in diameter and 8.6 cm tall. The paramagnetic liquid was a 3.3 molar solution of MnCl2 in water. Tests were performed with each type of tank filled to depths of 1 cm and 4 cm. Each test compared a pair of tanks that were identical except that the base of one was a pole face of a 0.6 Tesla permanent magnet. The Kelvin force attracts paramagnetic materials toward regions of higher magnetic field. It was hypothesized that the Kelvin force would hold the liquid in the bottom of the tanks during the periods of microgravity. The tanks were installed in a housing that could slide on rails transverse to the flight direction. By manually shoving the housing, an identical impulse could be provided to each tank at the beginning of each period of microgravity. The resulting fluid motions were videotaped for later analysis.

FY 1994 annual report. Advanced combustion science utilizing microgravity

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-10-01

Researches on combustion in microgravity were conducted to develop combustion devices for advanced combustion techniques, and thereby to cope with the requirements for diversification of energy sources and abatement of environmental pollution by exhaust gases. This project was implemented under the research cooperation agreement with US's NASA, and the Japanese experts visited NASA's test facilities. NASA's Lewis Research Center has drop test facilities, of which the 2.2-sec drop test facilities are useful for researches by Japan. The cooperative research themes for combustion in microgravity selected include interactions between fuel droplets, high-pressure combustion of binary fuel sprays, and ignition and subsequent flame propagation in microgravity. An ignition test equipment, density field measurement equipment and flame propagation test equipment were constructed in Japan to conduct the combustion tests in microgravity for, e.g., combustion and evaporation of fuel droplets, combustion characteristics of liquid fuels mixed with solid particles, combustion of coal/oil mixture droplets, and estimating flammability limits. (NEDO)

Experiments and Model Development for the Investigation of Sooting and Radiation Effects in Microgravity Droplet Combustion

Science.gov (United States)

Choi, Mun Young; Yozgatligil, Ahmet; Dryer, Frederick L.; Kazakov, Andrei; Dobashi, Ritsu

2001-01-01

Today, despite efforts to develop and utilize natural gas and renewable energy sources, nearly 97% of the energy used for transportation is derived from combustion of liquid fuels, principally derived from petroleum. While society continues to rely on liquid petroleum-based fuels as a major energy source in spite of their finite supply, it is of paramount importance to maximize the efficiency and minimize the environmental impact of the devices that burn these fuels. The development of improved energy conversion systems, having higher efficiencies and lower emissions, is central to meeting both local and regional air quality standards. This development requires improvements in computational design tools for applied energy conversion systems, which in turn requires more robust sub-model components for combustion chemistry, transport, energy transport (including radiation), and pollutant emissions (soot formation and burnout). The study of isolated droplet burning as a unidimensional, time dependent model diffusion flame system facilitates extensions of these mechanisms to include fuel molecular sizes and pollutants typical of conventional and alternative liquid fuels used in the transportation sector. Because of the simplified geometry, sub-model components from the most detailed to those reduced to sizes compatible for use in multi-dimensional, time dependent applied models can be developed, compared and validated against experimental diffusion flame processes, and tested against one another. Based on observations in microgravity experiments on droplet combustion, it appears that the formation and lingering presence of soot within the fuel-rich region of isolated droplets can modify the burning rate, flame structure and extinction, soot aerosol properties, and the effective thermophysical properties. These observations led to the belief that perhaps one of the most important outstanding contributions of microgravity droplet combustion is the observation that in the

Centrifuges for Microgravity Simulation. The Reduced Gravity Paradigm

International Nuclear Information System (INIS)

Loon, Jack J. W. A. van

2016-01-01

Due to the cumbersome nature of performing real microgravity—spaceflight research scientists have been searching for alternatives to perform simulated microgravity or partial gravity experiments on Earth. For more than a century one uses the slow rotating clinostat as developed by von Sachs at the end of the nineteenth century. Since then, the fast rotating clinostat, the 3D clinostat or the random positioning machine, the rotating wall vessels, tail suspension and bed rest head down tilt and lately the levitating magnets have been introduced. Several of these simulation systems provide some similarities of the responses and phenotypes as seen in real microgravity experiments. However, one should always realize that we cannot reduce gravity on Earth, other than the relative short duration free fall studies in e.g., drop towers or parabolic aircraft. In this paper we want to explore the possibility to apply centrifuges to simulate microgravity or maybe better to simulate hypo-gravity. This Reduced Gravity Paradigm, RGP is based on the premise that adaptations seen going from a hypergravity level to a lower gravity are similar as changes seen going from unit gravity to microgravity.

Centrifuges for Microgravity Simulation. The Reduced Gravity Paradigm

Energy Technology Data Exchange (ETDEWEB)

Loon, Jack J. W. A. van, E-mail: j.vanloon@vumc.nl [Department of Oral and Maxillofacial Surgery / Oral Pathology, Dutch Experiment Support Center, VU University Medical Center and Academic Centre for Dentistry Amsterdam, Amsterdam (Netherlands); TEC-MMG LIS Lab, European Space Agency Technology Center, Noordwijk (Netherlands)

2016-07-19

Due to the cumbersome nature of performing real microgravity—spaceflight research scientists have been searching for alternatives to perform simulated microgravity or partial gravity experiments on Earth. For more than a century one uses the slow rotating clinostat as developed by von Sachs at the end of the nineteenth century. Since then, the fast rotating clinostat, the 3D clinostat or the random positioning machine, the rotating wall vessels, tail suspension and bed rest head down tilt and lately the levitating magnets have been introduced. Several of these simulation systems provide some similarities of the responses and phenotypes as seen in real microgravity experiments. However, one should always realize that we cannot reduce gravity on Earth, other than the relative short duration free fall studies in e.g., drop towers or parabolic aircraft. In this paper we want to explore the possibility to apply centrifuges to simulate microgravity or maybe better to simulate hypo-gravity. This Reduced Gravity Paradigm, RGP is based on the premise that adaptations seen going from a hypergravity level to a lower gravity are similar as changes seen going from unit gravity to microgravity.

Control of the Onboard Microgravity Environment and Extension of the Service Life of the Long-Term Space Station

Science.gov (United States)

Titov, V. A.

2018-03-01

The problem of control of the on-board microgravity environment in order to extend the service life of the long-term space station has been discussed. Software developed for the ISS and the results of identifying dynamic models and external impacts based on telemetry data have been presented. Proposals for controlling the onboard microgravity environment for future long-term space stations have been formulated.

Operational factors affecting microgravity levels in orbit

Science.gov (United States)

Olsen, R. E.; Mockovciak, J., Jr.

1980-01-01

Microgravity levels desired for proposed materials processing payloads are fundamental considerations in the design of future space platforms. Disturbance sources, such as aerodynamic drag, attitude control torques, crew motion and orbital dynamics, influence the microgravity levels attainable in orbit. The nature of these effects are assessed relative to platform design parameters such as orbital altitude and configuration geometry, and examples are presented for a representative spacecraft configuration. The possible applications of control techniques to provide extremely low acceleration levels are also discussed.

Modeled microgravity suppressed invasion and migration of human glioblastoma U87 cells through downregulating store-operated calcium entry

Energy Technology Data Exchange (ETDEWEB)

Shi, Zi-xuan [Department of Traditional Chinese Medicine, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 (China); Rao, Wei [Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 (China); Wang, Huan [Department of Dermatology, Tangdu Hospital, Fourth Military Medical University, Xi' an, 710032 (China); Wang, Nan-ding [Department of Cardiology, Xi' an Traditional Chinese Medicine Hospital, Xi' an, 710032 (China); Si, Jing-Wen; Zhao, Jiao; Li, Jun-chang [Department of Traditional Chinese Medicine, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 (China); Wang, Zong-ren, E-mail: zongren@fmmu.edu.cn [Department of Traditional Chinese Medicine, Xijing Hospital, Fourth Military Medical University, Xi' an, 710032 (China)

2015-02-13

Glioblastoma is the most common brain tumor and is characterized with robust invasion and migration potential resulting in poor prognosis. Previous investigations have demonstrated that modeled microgravity (MMG) could decline the cell proliferation and attenuate the metastasis potential in several cell lines. In this study, we studied the effects of MMG on the invasion and migration potentials of glioblastoma in human glioblastoma U87 cells. We found that MMG stimulation significantly attenuated the invasion and migration potentials, decreased thapsigargin (TG) induced store-operated calcium entry (SOCE) and downregulated the expression of Orai1 in U87 cells. Inhibition of SOCE by 2-APB or stromal interaction molecule 1 (STIM1) downregulation both mimicked the effects of MMG on the invasion and migration potentials in U87 cells. Furthermore, upregulation of Orai1 significantly weakened the effects of MMG on the invasion and migration potentials in U87 cells. Therefore, these findings indicated that MMG stimulation inhibited the invasion and migration potentials of U87 cells by downregulating the expression of Orai1 and sequentially decreasing the SOCE, suggesting that MMG might be a new potential therapeutic strategy in glioblastoma treatment in the future. - Highlights: • Modeled microgravity (MMG) suppressed migration and invasion in U87 cells. • MMG downregulated the SOCE and the expression of Orai1. • SOCE inhibition mimicked the effects of MMG on migration and invasion potentials. • Restoration of SOCE diminished the effects of MMG on migration and invasion.

Modeled microgravity suppressed invasion and migration of human glioblastoma U87 cells through downregulating store-operated calcium entry

International Nuclear Information System (INIS)

Shi, Zi-xuan; Rao, Wei; Wang, Huan; Wang, Nan-ding; Si, Jing-Wen; Zhao, Jiao; Li, Jun-chang; Wang, Zong-ren

2015-01-01

Glioblastoma is the most common brain tumor and is characterized with robust invasion and migration potential resulting in poor prognosis. Previous investigations have demonstrated that modeled microgravity (MMG) could decline the cell proliferation and attenuate the metastasis potential in several cell lines. In this study, we studied the effects of MMG on the invasion and migration potentials of glioblastoma in human glioblastoma U87 cells. We found that MMG stimulation significantly attenuated the invasion and migration potentials, decreased thapsigargin (TG) induced store-operated calcium entry (SOCE) and downregulated the expression of Orai1 in U87 cells. Inhibition of SOCE by 2-APB or stromal interaction molecule 1 (STIM1) downregulation both mimicked the effects of MMG on the invasion and migration potentials in U87 cells. Furthermore, upregulation of Orai1 significantly weakened the effects of MMG on the invasion and migration potentials in U87 cells. Therefore, these findings indicated that MMG stimulation inhibited the invasion and migration potentials of U87 cells by downregulating the expression of Orai1 and sequentially decreasing the SOCE, suggesting that MMG might be a new potential therapeutic strategy in glioblastoma treatment in the future. - Highlights: • Modeled microgravity (MMG) suppressed migration and invasion in U87 cells. • MMG downregulated the SOCE and the expression of Orai1. • SOCE inhibition mimicked the effects of MMG on migration and invasion potentials. • Restoration of SOCE diminished the effects of MMG on migration and invasion

Heat transfer and combustion in microgravity; Mujuryokuka deno netsukogaku

Energy Technology Data Exchange (ETDEWEB)

Ito, K [Hokkaido University, Sapporo (Japan). Faculty of Engineering

1994-09-05

Examples of thermal engineering under gravity free state are introduced. When making semiconductor crystals, the thermal conductivity of the molten substance becomes important but in a microgravity environment where the thermal convection is suppressed, this value can be accurately measured. Although there are many unknown points regarding the thermal conductive mechanism of thermal control equipment elements under microgravity, theoretical analysis is being advanced. It is anticipated that the verification of this theory using liquid droplets will be made. The conveying of boiling heat under microgravity is suppressed because the bubbles stick to the heat source. When a non-azeotropic composition is used, Marangoni convection occurs, and the conveying is promoted. Since there is no thermal convection in microgravity combustion, diffusion dominates. In order to make the phenomenon clear, the free-fall tower can be utilized. A liquid droplet flame will become a complete, integrated, spherical flame. Vaporization coefficient and combustion velocity which are impossible to measure on the ground can be measured. In the case of metal fires occuring in space, the movement of metal dominates the combustion. In microgravity, dust coal will float in a stationary state so the process of combustion can be observed. It is believed that the diffusion flame of hydrocarbons will be thicker than the flame on the ground. 11 refs., 4 figs.

Responses, applications, and analysis of microgravity effects on bacteria

Science.gov (United States)

Benoit, Michael Robert

Spaceflight causes many changes to the growth and behavior of bacteria, most likely because of microgravity. However, we do not fully understand the gravity-dependent mechanisms that alter bacterial cell physiology. Furthermore, the literature consists of many contradictory results, creating controversy over the mechanisms by which spaceflight affects bacterial cultures. The research described in this dissertation combines empirical, analytical, and numerical modeling techniques aimed at characterizing the various gravity-dependent phenomena that act on bacteria. While reviewing the literature, I identified an interesting trend in prior experimental results regarding bacterial motility. With this information, we can begin to explain some of the seemingly contradictory findings. This discovery should help to resolve several controversial theories in the field of space microbiology. Chapter 3 describes a microbial antibiotic production experiment conducted onboard the International Space Station. The results corroborated earlier findings of increased antibiotic production for samples taken during the first two weeks of spaceflight. For later samples, however, a reversal occurred, showing decreased production in the spaceflight samples. This insight highlights the benefit of conducting long duration experiments in space to fully evaluate biological responses. Chapter 4 describes a novel technique for preventing bacterial cell sedimentation to partially simulate microgravity in ground-based experiments. The results of this study showed a correlation between cell sedimentation and bacterial growth. As documented in Chapter 5, I investigated the use of digital holographic interferometry to measure extracellular fluid density changes caused by bacterial metabolism. The results showed that fluid density changes surrounding individual bacteria were too small to measure directly. Therefore, I used mathematical analyses and numerical model simulations (described in Chapter 6

Studies of Fundamental Particle Dynamics in Microgravity

Science.gov (United States)

Rangel, Roger; Trolinger, James D.; Coimbra, Carlos F. M.; Witherow, William; Rogers, Jan; Rose, M. Franklin (Technical Monitor)

2001-01-01

This work summarizes theoretical and experimental concepts used to design the flight experiment mission for SHIVA - Spaceflight Holography Investigation in a Virtual Apparatus. SHIVA is a NASA project that exploits a unique, holography-based, diagnostics tool to understand the behavior of small particles subjected to transient accelerations. The flight experiments are designed for testing model equations, measuring g, g-jitter, and other microgravity phenomena. Data collection will also include experiments lying outside of the realm of existing theory. The regime under scrutiny is the low Reynolds number, Stokes regime or creeping flow, which covers particles and bubbles moving at very low velocity. The equations describing this important regime have been under development and investigation for over 100 years and yet a complete analytical solution of the general equation had remained elusive yielding only approximations and numerical solutions. In the course of the ongoing NASA NRA, the first analytical solution of the general equation was produced by members of the investigator team using the mathematics of fractional derivatives. This opened the way to an even more insightful and important investigation of the phenomena in microgravity. Recent results include interacting particles, particle-wall interactions, bubbles, and Reynolds numbers larger than unity. The Space Station provides an ideal environment for SHIVA. Limited ground experiments have already confirmed some aspects of the theory. In general the space environment is required for the overall experiment, especially for cases containing very heavy particles, very light particles, bubbles, collections of particles and for characterization of the space environment and its effect on particle experiments. Lightweight particles and bubbles typically rise too fast in a gravitational field and heavy particles sink too fast. In a microgravity environment, heavy and light particles can be studied side-by-side for

Terrestrial applications of bone and muscle research in microgravity

Science.gov (United States)

Booth, F. W.

1994-08-01

Major applications to people on Earth are possible from NASA-sponsored research on bone and muscle which is conducted either in microgravity or on Earth using models mimicking microgravity. In microgravity bone and muscle mass are lost. Humans experience a similar loss under certain conditions on Earth. Bone and muscle loss exist on Earth as humans age from adulthood to senescence, during limb immobilization for healing of orthopedic injuries, during wheelchair confinement because of certain diseases, and during chronic bed rest prescribed for curing of diseases. NASA-sponsored research is dedicated to learning both what cause bone and muscle loss as well as finding out how to prevent this loss. The health ramifications of these discoveries will have major impact. Objective 1.6 of Healthy People 2000, a report from the U.S. Department of Health and Human Services, states that the performance of physical activities that improve muscular strength, muscular endurance, and flexibility is particularly important to maintaining functional independence and social integration in older adults /1/. This objective further states that these types of physical activities are important because they may protect against disability, an event which costs the U.S. economy hugh sums of money. Thus NASA research related to bone and muscle loss has potential major impact on the quality of life in the U.S. Relative to its potential health benefits, NASA and Congressional support of bone and muscle research is funded is a very low level.

Categorization of Brazil nut effect and its reverse under less-convective conditions for microgravity geology

Science.gov (United States)

Chujo, Toshihiro; Mori, Osamu; Kawaguchi, Junichiro; Yano, Hajime

2018-03-01

Due to its important role in the sorting of particles on microgravity bodies by size, Brazil nut effect (BNE) is a major subject of study for understanding the evolution of planetesimals. Recent studies have revealed that the mechanism for the BNE on microgravity bodies is the percolation of particles or void-filling, rather than granular convection. This study also considers the mechanism for the BNE under `less-convective' conditions and introduces three categories of behaviour for particles that mainly depend on the dimensionless acceleration of vibration Γ (ratio of maximum acceleration to gravitational acceleration), using a simplified analytical model. The conditions for Γ proposed by the model for each category are verified by both numerical simulations and laboratory experiments. `Less-convective' conditions are realized by reducing the friction force between particles and the wall. We found three distinct behaviours of the particles when Γ > 1: the (i) `slow BNE', (ii) `fast BNE', and (iii) `fluid motion' (the reverse BNE may be induced), and the thresholds for Γ correspond well with those proposed by the simple model. We also applied this categorization to low-gravity environments and found that the categorization scales with gravity level. These results imply that laboratory experiments can provide knowledge of granular mobility on the surface of microgravity bodies.

A hydroponic design for microgravity and gravity installations

Science.gov (United States)

Fielder, Judith; Leggett, Nickolaus

1990-01-01

A hydroponic system is presented that is designed for use in microgravity or gravity experiments. The system uses a sponge-like growing medium installed in tubular modules. The modules contain the plant roots and manage the flow of the nutrient solution. The physical design and materials considerations are discussed, as are modifications of the basic design for use in microgravity or gravity experiments. The major external environmental requirements are also presented.

1998 annual report of advanced combustion science utilizing microgravity

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

For the purpose of stabilizing energy supply, diversifying energy supply sources and reducing the worsening of global environment caused by combustion exhaust gases, advanced combustion technology was studied and the FY 1998 results were summarized. Following the previous year, the following were conducted: international research jointly with NASA, experiments using microgravity test facilities of Japan Space Utilization Promotion Center (JSUP), evaluation studies made by universities/national research institutes/private companies, etc. In the FY 1998 joint study, a total of 52 drop experiments were carried out on 4 themes using test facilities of Japan Microgravity Center (JAMIC), and 100 experiments were conducted on one theme using test facilities of NASA. In the study using microgravity test facilities, the following were carried out: study of combustion and evaporation of fuel droplets, study of ignition/combustion of fuel droplets in the suspending state, study of combustion of spherical/cylinder state liquid fuels, study of high pressure combustion of binary fuel spray, study of interaction combustion of fuel droplets in the microgravity field, etc. (NEDO)

Homogeneous SiGe crystal growth in microgravity by the travelling liquidus-zone method

International Nuclear Information System (INIS)

Kinoshita, K; Arai, Y; Inatomi, Y; Sakata, K; Takayanagi, M; Yoda, S; Miyata, H; Tanaka, R; Sone, T; Yoshikawa, J; Kihara, T; Shibayama, H; Kubota, Y; Shimaoka, T; Warashina, Y

2011-01-01

Homogeneous SiGe crystal growth experiments will be performed on board the ISS 'Kibo' using a gradient heating furnace (GHF). A new crystal growth method invented for growing homogeneous mixed crystals named 'travelling liquidus-zone (TLZ) method' is evaluated by the growth of Si 0.5 Ge 0.5 crystals in space. We have already succeeded in growing homogeneous 2mm diameter Si 0.5 Ge 0.5 crystals on the ground but large diameter homogeneous crystals are difficult to be grown due to convection in a melt. In microgravity, larger diameter crystals can be grown with suppressing convection. Radial concentration profiles as well as axial profiles in microgravity grown crystals will be measured and will be compared with our two-dimensional TLZ growth model equation and compositional variation is analyzed. Results are beneficial for growing large diameter mixed crystals by the TLZ method on the ground. Here, we report on the principle of the TLZ method for homogeneous crystal growth, results of preparatory experiments on the ground and plan for microgravity experiments.

Pulmonary function in microgravity

Science.gov (United States)

Guy, H. J.; Prisk, G. K.; West, J. B.

1992-01-01

We report the successful collection of a large quantity of human resting pulmonary function data on the SLS-1 mission. Preliminary analysis suggests that cardiac stroke volumes are high on orbit, and that an adaptive reduction takes at least several days, and in fact may still be in progress after 9 days on orbit. It also suggests that pulmonary capillary blood volumes are high, and remain high on orbit, but that the pulmonary interstitium is not significantly impacted. The data further suggest that the known large gravitational gradients of lung function have only a modest influence on single breath tests such as the SBN washout. They account for only approximately 25% of the phase III slope of nitrogen, on vital capacity SBN washouts. These gradients are only a moderate source of the cardiogenic oscillations seen in argon (bolus gas) and nitrogen (resident gas), on such tests. They may have a greater role in generating the normal CO2 oscillations, as here the phase relationship to argon and nitrogen reverses in microgravity, at least at mid exhalation in those subjects studied to date. Microgravity may become a useful tool in establishing the nature of the non-gravitational mechanisms that can now be seen to play such a large part in the generation of intra-breath gradients and oscillations of expired gas concentration. Analysis of microgravity multibreath nitrogen washouts, single breath washouts from more physiological pre-inspiratory volumes, both using our existing SLS-1 data, and data from the upcoming D-2 and SLS-2 missions, should be very fruitful in this regard.(ABSTRACT TRUNCATED AT 250 WORDS).

Influence of microgravity on cellular differentiation in root caps of Zea mays

Science.gov (United States)

Moore, R.; Fondren, W. M.; McClelen, C. E.; Wang, C. L.

1987-01-01

We launched imbibed seeds of Zea mays into outer space aboard the space shuttle Columbia to determine the influence of microgravity on cellular differentiation in root caps. The influence of microgravity varied with different stages of cellular differentiation. Overall, microgravity tended to 1) increase relative volumes of hyaloplasm and lipid bodies, 2) decrease the relative volumes of plastids, mitochondria, dictyosomes, and the vacuome, and 3) exert no influence on the relative volume of nuclei in cells comprising the root cap. The reduced allocation of dictyosomal volume in peripheral cells of flight-grown seedlings correlated positively with their secretion of significantly less mucilage than peripheral cells of Earth-grown seedlings. These results indicate that 1) microgravity alters the patterns of cellular differentiation and structures of all cell types comprising the root cap, and 2) the influence of microgravity on cellular differentiation in root caps of Zea mays is organelle specific.

Microgravity Stress: Bone and Connective Tissue.

Science.gov (United States)

Bloomfield, Susan A; Martinez, Daniel A; Boudreaux, Ramon D; Mantri, Anita V

2016-03-15

The major alterations in bone and the dense connective tissues in humans and animals exposed to microgravity illustrate the dependency of these tissues' function on normal gravitational loading. Whether these alterations depend solely on the reduced mechanical loading of zero g or are compounded by fluid shifts, altered tissue blood flow, radiation exposure, and altered nutritional status is not yet well defined. Changes in the dense connective tissues and intervertebral disks are generally smaller in magnitude but occur more rapidly than those in mineralized bone with transitions to 0 g and during recovery once back to the loading provided by 1 g conditions. However, joint injuries are projected to occur much more often than the more catastrophic bone fracture during exploration class missions, so protecting the integrity of both tissues is important. This review focuses on the research performed over the last 20 years in humans and animals exposed to actual spaceflight, as well as on knowledge gained from pertinent ground-based models such as bed rest in humans and hindlimb unloading in rodents. Significant progress has been made in our understanding of the mechanisms for alterations in bone and connective tissues with exposure to microgravity, but intriguing questions remain to be solved, particularly with reference to biomedical risks associated with prolonged exploration missions. Copyright © 2016 John Wiley & Sons, Inc.

Polymethylmethacrylate combustion in a narrow channel apparatus simulating a microgravity environment

Science.gov (United States)

Bornand, Garrett Randall

compared to results found by Michigan State University's NCA. Flame spread results from the SDSU NCA compare closely to that of the other experimental techniques. Additionally, an infrared camera and species concentration sensors were added to the SDSU NCA and initial results are provided. Fire Dynamics Simulator (FDS) was used to model the combustion of PMMA within the SDSU NCA. Both thin and thick fuel beds were simulated and the numerical results were compared to experimental data. The simulation was then used to determine various results that cannot easily be found with experimentation, including how effectively the NCA simulates microgravity under certain environmental conditions, gas and fuel bed temperatures, heat fluxes, species concentrations, pyrolysis rate, and other various data. The simulation was found to give reasonable results and overall flame spread trends, but could be improved upon with further detailed kinetic parameter studies.

International cooperative research project between NEDO and NASA on advanced combustion science utilizing microgravity

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

This paper describes an international cooperative research project between NEDO and NASA on advanced combustion science utilizing microgravity. In June, 1994, NEDO and NASA reached a basic agreement with each other about this cooperative R and D on combustion under microgravity conditions. In fiscal 2000, Japan proposed an experiment using the drop tower facilities and parabolic aircraft at NASA Glen Research Center and at JAMIC (Japan Microgravity Center). In other words, the proposals from Japan included experiments on combustion of droplets composed of diversified fuels under different burning conditions (vaporization), flame propagation in smoldering porous materials and dispersed particles under microgravity conditions, and control of interactive combustion of two droplets by acoustical and electrical perturbations. Additionally proposed were experiments on effect of low external air flow on solid material combustion under microgravity, and sooting and radiation effects on the burning of large droplets under microgravity conditions. This report gives an outline of the results of these five cooperative R and D projects. The experiments were conducted under ordinary normal gravity and microgravity conditions, with the results compared and examined mutually. (NEDO)

Regulation of ICAM-1 in Cells of the Monocyte/Macrophage System in Microgravity

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Katrin Paulsen

2015-01-01

Full Text Available Cells of the immune system are highly sensitive to altered gravity, and the monocyte as well as the macrophage function is proven to be impaired under microgravity conditions. In our study, we investigated the surface expression of ICAM-1 protein and expression of ICAM-1 mRNA in cells of the monocyte/macrophage system in microgravity during clinostat, parabolic flight, sounding rocket, and orbital experiments. In murine BV-2 microglial cells, we detected a downregulation of ICAM-1 expression in clinorotation experiments and a rapid and reversible downregulation in the microgravity phase of parabolic flight experiments. In contrast, ICAM-1 expression increased in macrophage-like differentiated human U937 cells during the microgravity phase of parabolic flights and in long-term microgravity provided by a 2D clinostat or during the orbital SIMBOX/Shenzhou-8 mission. In nondifferentiated U937 cells, no effect of microgravity on ICAM-1 expression could be observed during parabolic flight experiments. We conclude that disturbed immune function in microgravity could be a consequence of ICAM-1 modulation in the monocyte/macrophage system, which in turn could have a strong impact on the interaction with T lymphocytes and cell migration. Thus, ICAM-1 can be considered as a rapid-reacting and sustained gravity-regulated molecule in mammalian cells.

Psychophysiology in microgravity and the role of exercise

Science.gov (United States)

Shaw, J. M.; Hackney, A. C.

1994-01-01

The Space Transportation-Shuttle (STS) Program has greatly expanded our capabilities in space by allowing for missions to be flown more frequently, less expensively, and to encompass a greater range of goals than ever before. However, the scope of the United State's role and involvement in space is currently at the edge of a new and exciting era. The National Aeronautics and Space Administration (NASA) has plans for placing an orbiting space station (Space Station Freedom) into operation before the year 2000. Space Station Freedom promises to redefine the extent of our involvement in space even further than the STS program. Space Station crewmembers will be expected to spend extended periods of time (approximately 30 to 180 days) in space exposed to an extremely diverse and adverse environment (e.g., the major adversity being the chronic microgravity condition). Consequently, the detrimental effects of exposure to the microgravity environment is of primary importance to the biomedical community responsible for the health and well-being of the crewmembers. Space flight and microgravity exposure present a unique set of stressors for the crewmember; weightlessness, danger, isolation/confinement, irregular work-rest cycles, separation from family/friends, and mission/ground crew interrelationships. A great deal is beginning to be known about the physiological changes associated with microgravity exposure, however, limited objective psychological findings exist. Examination of this latter area will become of critical concern as NASA prepares to place crewmembers on the longer space missions that will be required on Space Station Freedom. Psychological factors, such as interpersonal relations will become increasingly important issues, especially as crews become more heterogeneous in the way of experience, professional background, and assigned duties. In an attempt to minimize the detrimental physiological effects of prolonged space flight and microgravity exposure, the

Investigation of the Influence of Microgravity on Transport Mechanism in a Virtual Spaceflight Chamber: A Flight Definition Program

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Trolinger, James D.; Rangel, Roger; Witherow, William; Rogers, Jan; Lal, Ravindra B.

1999-01-01

A need exists for understanding precisely how particles move and interact in a fluid in the absence of gravity. Such understanding is required, for example, for modeling and predicting crystal growth in space where crystals grow from solution around nucleation sites as well as for any study of particles or bubbles in liquids or in experiments where particles are used as tracers for mapping microconvection. We have produced an exact solution to the general equation of motion of particles at extremely low Reynolds number in microgravity that covers a wide range of interesting conditions. We have also developed diagnostic tools and experimental techniques to test the validity of the general equation . This program, which started in May, 1998, will produce the flight definition for an experiment in a microgravity environment of space to validate the theoretical model. We will design an experiment with the help of the theoretical model that is optimized for testing the model, measuring g, g-jitter, and other microgravity phenomena. This paper describes the goals, rational, and approach for the flight definition program. The first objective of this research is to understand the physics of particle interactions with fluids and other particles in low Reynolds number flows in microgravity. Secondary objectives are to (1) observe and quantify g-jitter effects and microconvection on particles in fluids, (2) validate an exact solution to the general equation of motion of a particle in a fluid, and (3) to characterize the ability of isolation tables to isolate experiments containing particle in liquids. The objectives will be achieved by recording a large number of holograms of particle fields in microgravity under controlled conditions, extracting the precise three-dimensional position of all of the particles as a function of time and examining the effects of all parameters on the motion of the particles. The feasibility for achieving these results has already been established

Comparison of Simulated Microgravity and Hydrostatic Pressure for Chondrogenesis of hASC.

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Mellor, Liliana F; Steward, Andrew J; Nordberg, Rachel C; Taylor, Michael A; Loboa, Elizabeth G

2017-04-01

Cartilage tissue engineering is a growing field due to the lack of regenerative capacity of native tissue. The use of bioreactors for cartilage tissue engineering is common, but the results are controversial. Some studies suggest that microgravity bioreactors are ideal for chondrogenesis, while others show that mimicking hydrostatic pressure is crucial for cartilage formation. A parallel study comparing the effects of loading and unloading on chondrogenesis has not been performed. The goal of this study was to evaluate chondrogenesis of human adipose-derived stem cells (hASC) under two different mechanical stimuli relative to static culture: microgravity and cyclic hydrostatic pressure (CHP). Pellets of hASC were cultured for 14 d under simulated microgravity using a rotating wall vessel bioreactor or under CHP (7.5 MPa, 1 Hz, 4 h · d-1) using a hydrostatic pressure vessel. We found that CHP increased mRNA expression of Aggrecan, Sox9, and Collagen II, caused a threefold increase in sulfated glycosaminoglycan production, and resulted in stronger vimentin staining intensity and organization relative to microgravity. In addition, Wnt-signaling patterns were altered in a manner that suggests that simulated microgravity decreases chondrogenic differentiation when compared to CHP. Our goal was to compare chondrogenic differentiation of hASC using a microgravity bioreactor and a hydrostatic pressure vessel, two commonly used bioreactors in cartilage tissue engineering. Our results indicate that CHP promotes hASC chondrogenesis and that microgravity may inhibit hASC chondrogenesis. Our findings further suggest that cartilage formation and regeneration might be compromised in space due to the lack of mechanical loading.Mellor LF, Steward AJ, Nordberg RC, Taylor MA, Loboa EG. Comparison of simulated microgravity and hydrostatic pressure for chondrogenesis of hASC. Aerosp Med Hum Perform. 2017; 88(4):377-384.

Removing Regional Trends in Microgravity in Complex Environments: Testing on 3D Model and Field Investigations in the Eastern Dead Sea Coast (Jordan

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A. Al-Zoubi

2013-01-01

Full Text Available Microgravity investigations are now recognized as a powerful tool for subsurface imaging and especially for the localization of underground karsts. However numerous natural (geological, technical, and environmental factors interfere with microgravity survey processing and interpretation. One of natural factors that causes the most disturbance in complex geological environments is the influence of regional trends. In the Dead Sea coastal areas the influence of regional trends can exceed residual gravity effects by some tenfold. Many widely applied methods are unable to remove regional trends with sufficient accuracy. We tested number of transformation methods (including computing gravity field derivatives, self-adjusting and adaptive filtering, Fourier series, wavelet, and other procedures on a 3D model (complicated by randomly distributed noise, and field investigations were carried out in Ghor Al-Haditha (the eastern side of the Dead Sea in Jordan. We show that the most effective methods for regional trend removal (at least for the theoretical and field cases here are the bilinear saddle and local polynomial regressions. Application of these methods made it possible to detect the anomalous gravity effect from buried targets in the theoretical model and to extract the local gravity anomaly at the Ghor Al-Haditha site. The local anomaly was utilized for 3D gravity modeling to construct a physical-geological model (PGM.

Effect of Oxygen Enrichment in Propane Laminar Diffusion Flames under Microgravity and Earth Gravity Conditions

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Bhatia, Pramod; Singh, Ravinder

2017-06-01

Diffusion flames are the most common type of flame which we see in our daily life such as candle flame and match-stick flame. Also, they are the most used flames in practical combustion system such as industrial burner (coal fired, gas fired or oil fired), diesel engines, gas turbines, and solid fuel rockets. In the present study, steady-state global chemistry calculations for 24 different flames were performed using an axisymmetric computational fluid dynamics code (UNICORN). Computation involved simulations of inverse and normal diffusion flames of propane in earth and microgravity condition with varying oxidizer compositions (21, 30, 50, 100 % O2, by mole, in N2). 2 cases were compared with the experimental result for validating the computational model. These flames were stabilized on a 5.5 mm diameter burner with 10 mm of burner length. The effect of oxygen enrichment and variation in gravity (earth gravity and microgravity) on shape and size of diffusion flames, flame temperature, flame velocity have been studied from the computational result obtained. Oxygen enrichment resulted in significant increase in flame temperature for both types of diffusion flames. Also, oxygen enrichment and gravity variation have significant effect on the flame configuration of normal diffusion flames in comparison with inverse diffusion flames. Microgravity normal diffusion flames are spherical in shape and much wider in comparison to earth gravity normal diffusion flames. In inverse diffusion flames, microgravity flames were wider than earth gravity flames. However, microgravity inverse flames were not spherical in shape.

Toward Understanding Pore Formation and Mobility during Controlled Directional Solidification in a Microgravity Environment Investigation (PFMI)

Science.gov (United States)

Grugel, Richard N.; Anilkumar, A. V.; Luz, Paul; Jeter, Linda; Volz, Martin P.; Spivey, Reggie; Smith, G.

2003-01-01

The generation and inclusion of detrimental porosity, e.g., pipes and rattails can occur during controlled directional solidification processing. The origin of these defects is generally attributed to gas evolution and entrapment during solidification of the melt. On Earth, owing to buoyancy, an initiated bubble can rapidly rise through the liquid melt and pop at the surface; this is obviously not ensured in a low gravity or microgravity environment. Clearly, porosity generation and inclusion is detrimental to conducting any meaningful solidification-science studies in microgravity. Thus it is essential that model experiments be conducted in microgravity, to understand the details of the generation and mobility of porosity, so that methods can be found to eliminate it. In hindsight, this is particularly relevant given the results of the previous directional solidification experiments conducted in Space. The current International Space Station (ISS) Microgravity Science Glovebox (MSG) investigation addresses the central issue of porosity formation and mobility during controlled directional solidification processing in microgravity. The study will be done using a transparent metal-analogue material, succinonitrile (SCN) and succinonitrile-water 'alloys', so that direct observation and recording of pore generation and mobility can be made during the experiments. Succinonitrile is particularly well suited for the proposed investigation because it is transparent, it solidifies in a manner analogous to most metals, it has a convenient melting point, its material properties are well characterized and, it has been successfully used in previous microgravity experiments. The PFMI experiment will be launched on the UF-2, STS-111 flight. Highlighting the porosity development problem in metal alloys during microgravity processing, the poster will describe: (i) the intent of the proposed experiments, (ii) the theoretical rationale behind using SCN as the study material for

Microgravity simulation activates Cdc42 via Rap1GDS1 to promote vascular branch morphogenesis during vasculogenesis

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Shouli Wang

2017-12-01

Full Text Available Gravity plays an important role in normal tissue maintenance. The ability of stem cells to repair tissue loss in space through regeneration and differentiation remains largely unknown. To investigate the impact of microgravity on blood vessel formation from pluripotent stem cells, we employed the embryoid body (EB model for vasculogenesis and simulated microgravity by clinorotation. We first differentiated mouse embryonic stem cells into cystic EBs containing two germ layers and then analyzed vessel formation under clinorotation. We observed that endothelial cell differentiation was slightly reduced under clinorotation, whereas vascular branch morphogenesis was markedly enhanced. EB-derived endothelial cells migrated faster, displayed multiple cellular processes, and had higher Cdc42 and Rac1 activity when subjected to clinorotation. Genetic analysis and rescue experiments demonstrated that Cdc42 but not Rac1 is required for microgravity-induced vascular branch morphogenesis. Furthermore, affinity pull-down assay and mass spectrometry identified Rap1GDS1 to be a Cdc42 guanine nucleotide exchange factor, which was upregulated by clinorotation. shRNA-mediated knockdown of Rap1GDS1 selectively suppressed Cdc42 activation and inhibited both baseline and microgravity-induced vasculogenesis. This was rescued by ectopic expression of constitutively active Cdc42. Taken together, these results support the notion that simulated microgravity activates Cdc42 via Rap1GDS1 to promote vascular branch morphogenesis.

Microgravity science and applications projects and payloads

Science.gov (United States)

Crouch, R. K.

1987-01-01

An overview of work conducted by the Microgravity Science and Applications Division of NASA is presented. The goals of the program are the development and implementation of a reduced-gravity research, science and applications program, exploitation of space for human benefits, and the application of reduced gravity research for the development of advanced technologies. Space research of fluid dynamics and mass transport phenomena is discussed and the facilities available for reduced gravity experiments are presented. A program for improving communication with the science and applications communities and the potential use of the Space Station for microgravity research are also examined.

Plasticity of mesenchymal stem cells under microgravity: from cytoskeletal reorganization to commitment shift

Science.gov (United States)

Buravkova, Ludmila

Mesenchymal stem cells (MSCs) can be used to examine osteogenesis of uncommitted cells maintaining the bone differentiation potential such as osteogenic gene expression, osteogenic markers, matrix maturation and mineralization. MSCs are therefore a good model for studying osteogenesis in the space environment. Recent investigations have demonstrated that MSCs change in response to microgravity and, consequently, can be involved in the development of osteopenia detected in space travelers. This is a factor that can limit human space missions due to potential risks of osteoporosis and its aftereffects during and after flight. Simulated microgravity inhibited MSC differentiation towards osteoblasts and accelerated adipocyte development due to cytoskeleton modifications, including its structure and regulation associated with signal transduction cascades. We identified transient changes in the actin cytoskeleton of non-committed human bone marrow MSCs in short-term RPM experiments. In addition, we detected transient changes in the expression of genes encoding actin cytoskeleton proteins and associated elements (ACTA1, ACTG, RHOA, CFL1, VCL). When discussing the microgravity effects on MSC osteogenic differentiation, it should be mentioned the inhibition of Runx2 and ALPL and stimulation of PPARg2 in the MSCs induced for osteogenesis. It is probable that the reciprocal regulation of the two transcription factors is a molecular mechanism underlying progenitor cell response to microgravity. It is very likely that these genes are involved in the universal circuits within which mechanical (or gravity ) signals are sensed by MSCs. Recently, the list of osteogenic markers was extended to include several new proteins as microgravity targets (proteoglycans, osteomodulin, osteoglycin). It can be believed that exposure to microgravity produces similar effects on mature bone cells (osteoblasts) and non-committed osteogenic cells (MSCs). This finds a support in the fact that

Microgravity Effects on Yersinia Pestis Virulence

Science.gov (United States)

Lawal, A.; Abogunde, O.; Jejelowo, O.; Rosenzweig, J.-A.

2010-04-01

Microgravity effects on Yersinia pestis proliferation, cold growth, and type three secretion system function were evaluated in macrophage cell infections, HeLa cell infections, and cold growth plate assays.

Microgravity induced changes in the control of motor units

Science.gov (United States)

de Luca, C.; Roy, S.

The goal of this project is to understand the effects of microgravity on the control of muscles. It is motivated by the notion that in order to adequately address microgravity-induced deterioration in the force generating capacity of muscles, one needs to understand the changes in the control aspects in addition to histochemical and morphological changes. The investigations into muscle control need to include the regulation of the firing activity of motor units that make up a muscle and the coordination of different muscles responsible for the control of a joint. In order to understand the effects of microgravity on these two aspects of muscle control, we will test astronauts before and after spaceflight. The investigations of the control of motor units will involve intramuscular EMG techniques developed in our laboratory. We will use a quadrifilar electrode to detect simultaneously three differential channels of EMG activity. These data will be decomposed accurately using a sophisticated set of algorithms constructed with artificial intelligence knowledge- based techniques. Particular attention will be paid to the firing rate and recruitment behavior of motor units and we will study the degree of cross-correlation of the firing rates. This approach will enable us to study the firing behavior of several (approx. 10) concurrently active motor units. This analysis will enable us to detect modifications in the control of motor units. We will perform these investigations in a hand muscle, which continues being used in prehensile tasks in space, and a leg muscle whose antigravity role is not needed in space. The comparison of the effects of weightlessness on these muscles will determine if continued use of muscles in space deters the possible deleterious effects of microgravity on the control of motor units, in addition to slowing down atrophy. We are particularly interested in comparing the results of this study to similar data already obtained from elderly subjects

Measurement of interfacial tension of immiscible liquid pairs in microgravity

Science.gov (United States)

Weinberg, Michael C.; Neilson, George F.; Baertlein, Carl; Subramanian, R. Shankar; Trinh, Eugene H.

1994-01-01

A discussion is given of a containerless microgravity experiment aimed at measuring the interfacial tension of immiscible liquid pairs using a compound drop rotation method. The reasons for the failure to execute such experiments in microgravity are described. Also, the results of post-flight analyses used to confirm our arguments are presented.

A Novel Microgravity Simulator Applicable for Three-Dimensional Cell Culturing

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Wuest, Simon L.; Richard, Stéphane; Walther, Isabelle; Furrer, Reinhard; Anderegg, Roland; Sekler, Jörg; Egli, Marcel

2014-10-01

Random Positioning Machines (RPM) were introduced decades ago to simulate microgravity. Since then numerous experiments have been carried out to study its influence on biological samples. The machine is valued by the scientific community involved in space relevant topics as an excellent experimental tool to conduct pre-studies, for example, before sending samples into space. We have developed a novel version of the traditional RPM to broaden its operative range. This novel version has now become interesting to researchers who are working in the field of tissue engineering, particularly those interested in alternative methods for three-dimensional (3D) cell culturing. The main modifications concern the cell culture condition and the algorithm that controls the movement of the frames for the nullification of gravity. An incubator was integrated into the inner frame of the RPM allowing precise control over the cell culture environment. Furthermore, several feed-throughs now allow a permanent supply of gas like CO 2. All these modifications substantially improve conditions to culture cells; furthermore, the rewritten software responsible for controlling the movement of the frames enhances the quality of the generated microgravity. Cell culture experiments were carried out with human lymphocytes on the novel RPM model to compare the obtained response to the results gathered on an older well-established RPM as well as to data from space flights. The overall outcome of the tests validates this novel RPM for cell cultivation under simulated microgravity conditions.

Identification of genes for small non-coding RNAs that belong to the regulon of the two-component regulatory system CiaRH in Streptococcus

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Hakenbeck Regine

2010-11-01

Full Text Available Abstract Background Post-transcriptional regulation by small RNAs (sRNAs in bacteria is now recognized as a wide-spread regulatory mechanism modulating a variety of physiological responses including virulence. In Streptococcus pneumoniae, an important human pathogen, the first sRNAs to be described were found in the regulon of the CiaRH two-component regulatory system. Five of these sRNAs were detected and designated csRNAs for cia-dependent small RNAs. CiaRH pleiotropically affects β-lactam resistance, autolysis, virulence, and competence development by yet to be defined molecular mechanisms. Since CiaRH is highly conserved among streptococci, it is of interest to determine if csRNAs are also included in the CiaRH regulon in this group of organisms consisting of commensal as well as pathogenic species. Knowledge on the participation of csRNAs in CiaRH-dependent regulatory events will be the key to define the physiological role of this important control system. Results Genes for csRNAs were predicted in streptococcal genomes and data base entries other than S. pneumoniae by searching for CiaR-activated promoters located in intergenic regions that are followed by a transcriptional terminator. 61 different candidate genes were obtained specifying csRNAs ranging in size from 51 to 202 nt. Comparing these genes among each other revealed 40 different csRNA types. All streptococcal genomes harbored csRNA genes, their numbers varying between two and six. To validate these predictions, S. mitis, S. oralis, and S. sanguinis were subjected to csRNA-specific northern blot analysis. In addition, a csRNA gene from S. thermophilus plasmid pST0 introduced into S. pneumoniae was also tested. Each of the csRNAs was detected on these blots and showed the anticipated sizes. Thus, the method applied here is able to predict csRNAs with high precision. Conclusions The results of this study strongly suggest that genes for small non-coding RNAs, csRNAs, are part of

Effect of Simulated Microgravity on the Activity of Regulatory Enzymes of Glycolysis and Gluconeogenesis in Mice Liver

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Ramirez, Joaquin; Periyakaruppan, Adaikkappan; Sarkar, Shubhashish; Ramesh, Govindarajan T.; Sharma, S. Chidananda

2014-02-01

Gravity supports all the life activities present on earth. Microgravity environments have effect on the biological functions and physiological status of an individual. The present study was undertaken to investigate the effect of simulated microgravity on important regulatory enzymes of carbohydrate metabolism in liver using HLS mice model. Following hind limb unloading of mice for 11 days the animal's average body weights were found to be not different, while the liver weights were decreased and found to be significantly different ( p gluconeogenesis in liver and reciprocally regulated.

CAFE simulation of columnar-to-equiaxed transition in Al-7wt%Si alloys directionally solidified under microgravity

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Liu, D. R.; Mangelinck-Noël, N.; Gandin, Ch-A.; Zimmermann, G.; Sturz, L.; Nguyen Thi, H.; Billia, B.

2016-03-01

A two-dimensional multi-scale cellular automaton - finite element (CAFE) model is used to simulate grain structure evolution and microsegregation formation during solidification of refined Al-7wt%Si alloys under microgravity. The CAFE simulations are first qualitatively compared with the benchmark experimental data under microgravity. Qualitative agreement is obtained for the position of columnar to equiaxed transition (CET) and the CET transition mode (sharp or progressive). Further comparisons of the distributions of grain elongation factor and equivalent diameter are conducted and reveal a fair quantitative agreement.

Analysis of miRNA and mRNA Expression Profiles Highlights Alterations in Ionizing Radiation Response of Human Lymphocytes under Modeled Microgravity

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Casara, Silvia; Sales, Gabriele; Lanfranchi, Gerolamo; Celotti, Lucia; Mognato, Maddalena

2012-01-01

Background Ionizing radiation (IR) can be extremely harmful for human cells since an improper DNA-damage response (DDR) to IR can contribute to carcinogenesis initiation. Perturbations in DDR pathway can originate from alteration in the functionality of the microRNA-mediated gene regulation, being microRNAs (miRNAs) small noncoding RNA that act as post-transcriptional regulators of gene expression. In this study we gained insight into the role of miRNAs in the regulation of DDR to IR under microgravity, a condition of weightlessness experienced by astronauts during space missions, which could have a synergistic action on cells, increasing the risk of radiation exposure. Methodology/Principal Findings We analyzed miRNA expression profile of human peripheral blood lymphocytes (PBL) incubated for 4 and 24 h in normal gravity (1 g) and in modeled microgravity (MMG) during the repair time after irradiation with 0.2 and 2Gy of γ-rays. Our results show that MMG alters miRNA expression signature of irradiated PBL by decreasing the number of radio-responsive miRNAs. Moreover, let-7i*, miR-7, miR-7-1*, miR-27a, miR-144, miR-200a, miR-598, miR-650 are deregulated by the combined action of radiation and MMG. Integrated analyses of miRNA and mRNA expression profiles, carried out on PBL of the same donors, identified significant miRNA-mRNA anti-correlations of DDR pathway. Gene Ontology analysis reports that the biological category of “Response to DNA damage” is enriched when PBL are incubated in 1 g but not in MMG. Moreover, some anti-correlated genes of p53-pathway show a different expression level between 1 g and MMG. Functional validation assays using luciferase reporter constructs confirmed miRNA-mRNA interactions derived from target prediction analyses. Conclusions/Significance On the whole, by integrating the transcriptome and microRNome, we provide evidence that modeled microgravity can affects the DNA-damage response to IR in human PBL. PMID:22347458

Scanning probe microscopy experiments in microgravity

International Nuclear Information System (INIS)

Drobek, Tanja; Reiter, Michael; Heckl, Wolfgang M.

2004-01-01

The scanning probe microscopy setups are small, lightweight and do not require vacuum or high voltage supply. In addition, samples can be investigated directly without further preparation. Therefore, these techniques are well-suited for applications in space, in particular, for operation on the International Space Station (ISS) or for high resolution microscopy on planetary missions. A feasibility study for a scanning tunneling microscopy setup was carried out on a parabolic flight campaign in November 2001 in order to test the technical setup for microgravity applications. With a pocket-size design microscope, a graphite surface was imaged under ambient conditions. Atomic resolution was achieved although the quality of the images was inferior in comparison to laboratory conditions. Improvements for future scanning probe microscopy experiments in microgravity are suggested

Microgravity Fluids for Biology, Workshop

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Griffin, DeVon; Kohl, Fred; Massa, Gioia D.; Motil, Brian; Parsons-Wingerter, Patricia; Quincy, Charles; Sato, Kevin; Singh, Bhim; Smith, Jeffrey D.; Wheeler, Raymond M.

2013-01-01

Microgravity Fluids for Biology represents an intersection of biology and fluid physics that present exciting research challenges to the Space Life and Physical Sciences Division. Solving and managing the transport processes and fluid mechanics in physiological and biological systems and processes are essential for future space exploration and colonization of space by humans. Adequate understanding of the underlying fluid physics and transport mechanisms will provide new, necessary insights and technologies for analyzing and designing biological systems critical to NASAs mission. To enable this mission, the fluid physics discipline needs to work to enhance the understanding of the influence of gravity on the scales and types of fluids (i.e., non-Newtonian) important to biology and life sciences. In turn, biomimetic, bio-inspired and synthetic biology applications based on physiology and biology can enrich the fluid mechanics and transport phenomena capabilities of the microgravity fluid physics community.

Action of microgravity on root development

Data.gov (United States)

National Aeronautics and Space Administration — Arabidopsis were grown on horizontal or vertical clinostat for 4 8 or 12 days. Seedlings on horizontal clinostat were in simulated microgravity and seedlings on...

The BvgAS Regulon of Bordetella pertussis

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Kyung Moon

2017-10-01

Full Text Available Nearly all virulence factors in Bordetella pertussis are activated by a master two-component system, BvgAS, composed of the sensor kinase BvgS and the response regulator BvgA. When BvgS is active, BvgA is phosphorylated (BvgA~P, and virulence-activated genes (vags are expressed [Bvg(+ mode]. When BvgS is inactive and BvgA is not phosphorylated, virulence-repressed genes (vrgs are induced [Bvg(− mode]. Here, we have used transcriptome sequencing (RNA-seq and reverse transcription-quantitative PCR (RT-qPCR to define the BvgAS-dependent regulon of B. pertussis Tohama I. Our analyses reveal more than 550 BvgA-regulated genes, of which 353 are newly identified. BvgA-activated genes include those encoding two-component systems (such as kdpED, multiple other transcriptional regulators, and the extracytoplasmic function (ECF sigma factor brpL, which is needed for type 3 secretion system (T3SS expression, further establishing the importance of BvgA~P as an apex regulator of transcriptional networks promoting virulence. Using in vitro transcription, we demonstrate that the promoter for brpL is directly activated by BvgA~P. BvgA-FeBABE cleavage reactions identify BvgA~P binding sites centered at positions −41.5 and −63.5 in bprL. Most importantly, we show for the first time that genes for multiple and varied metabolic pathways are significantly upregulated in the B. pertussis Bvg(− mode. These include genes for fatty acid and lipid metabolism, sugar and amino acid transporters, pyruvate dehydrogenase, phenylacetic acid degradation, and the glycolate/glyoxylate utilization pathway. Our results suggest that metabolic changes in the Bvg(− mode may be participating in bacterial survival, transmission, and/or persistence and identify over 200 new vrgs that can be tested for function.

ATF4 is involved in the regulation of simulated microgravity induced integrated stress response

Science.gov (United States)

Li, Yingxian; Li, Qi; Wang, Xiaogang; Sun, Qiao; Wan, Yumin; Li, Yinghui; Bai, Yanqiang

Objective: Many important metabolic and signaling pathways have been identified as being affected by microgravity, thereby altering cellular functions such as proliferation, differentiation, maturation and cell survival. It has been demonstrated that microgravity could induce all kinds of stress response such as endoplasmic reticulum stress and oxidative stress et al. ATF4 belongs to the ATF/CREB family of basic region leucine zipper transcription factors. ATF4 is induced by stress signals including anoxia/hypoxia, ER stress, amino acid deprivation and oxidative stress. ATF4 regulates the expression of genes involved in oxidative stress, amino acid synthesis, differentiation, metastasis and angiogenesis. The aim of this study was to examine the changes of ATF4 under microgravity, and to investigate the role of ATF4 in microgravity induced stress. MethodsMEF cells were cultured in clinostat to simulate microgravity. Reverse transcription polymerase chain reaction (RT-PCR) and western blotting were used to examine mRNA and protein levels of ATF4 expression under simulated microgravity in MEF cells. ROS levels were measured with the use of the fluorescent signal H2DCF-DA. GFP-XBP1 stably transfected cell lines was used to detect the extent of ER stress under microgravity by the intensity of GFP. Dual luciferase reporter assay was used to detect the activity of ATF4. Co-immunoprecipitation was performed to analyze protein interaction. Results: ATF4 protein levels in MEF cells increased under simulated microgravity. However, ATF4 mRNA levels were consistent. XBP1 splicing can be induced due to ER stress caused by simulated microgravity. At the same time, ROS levels were also increased. Increased ATF4 could promote the expression of CHOP, which is responsible for cell apoptosis. ATF4 also play an important role in cellular anti-oxidant stress. In ATF4 -/-MEF cells, the ROS levels after H2O2 treatment were obviously higher than that of wild type cells. HDAC4 was

CAFE simulation of columnar-to-equiaxed transition in Al-7wt%Si alloys directionally solidified under microgravity

International Nuclear Information System (INIS)

Liu, D R; Mangelinck-Noël, N; Thi, H Nguyen; Billia, B; Gandin, Ch-A; Zimmermann, G; Sturz, L

2016-01-01

A two-dimensional multi-scale cellular automaton - finite element (CAFE) model is used to simulate grain structure evolution and microsegregation formation during solidification of refined Al-7wt%Si alloys under microgravity. The CAFE simulations are first qualitatively compared with the benchmark experimental data under microgravity. Qualitative agreement is obtained for the position of columnar to equiaxed transition (CET) and the CET transition mode (sharp or progressive). Further comparisons of the distributions of grain elongation factor and equivalent diameter are conducted and reveal a fair quantitative agreement. (paper)

The role of nucleotides in augmentation of lymphocyte locomotion: Adaptional countermeasure development in microgravity analog environments

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Sundaresan, Alamelu; Kulkarni, Anil D.; Yamauchi, Keiko; Pellis, Neal R.

2006-09-01

Space travel and long-term space residence such as envisaged in the exploration era implicates burdens on the immune system. An optimal immune response is required to countered and with-stand exposure to pathogens. Countermeasure development is an important avenue in space research especially for long-term space exploration. Microgravity exposure causes detrimental effects in lymphocyte functions which may impair immune response. Impaired lymphocyte function can be remedied by bypassing cell membrane events. This is done by using compounds such as Phorbol Myristate Acetate (PMA). Since activation in mouse splenocytes was augmented using nucleotides, it was essential to observe their effects on human lymphocyte locomotion. A nucleotide/nucleoside (NT/NT) mixture from Otsuka Pharmaceuticals (Naruto, Japan) was used at recommended doses. In lymphocytes cultured in modeled microgravity, the NT/NT mixture used orchestrated locomotion recovery by more than 87%, similar to the response documented with PMA in lymphocytes. Both 12µM and 120µM doses worked similarly. These are preliminary results leading to the possible use of the NT/NT mixture to mitigate immune suppression in micro-gravity. More studies in this direction are required to delineate the role of NT/NT on the immune response in microgravity.

New Technologies Being Developed for the Thermophoretic Sampling of Smoke Particulates in Microgravity

Science.gov (United States)

Sheredy, William A.

2003-01-01

The Characterization of Smoke Particulate for Spacecraft Fire Detection, or Smoke, microgravity experiment is planned to be performed in the Microgravity Science Glovebox Facility on the International Space Station (ISS). This investigation, which is being developed by the NASA Glenn Research Center, ZIN Technologies, and the National Institute of Standards and Technologies (NIST), is based on the results and experience gained from the successful Comparative Soot Diagnostics experiment, which was flown as part of the USMP-3 (United States Microgravity Payload 3) mission on space shuttle flight STS-75. The Smoke experiment is designed to determine the particle size distributions of the smokes generated from a variety of overheated spacecraft materials and from microgravity fires. The objective is to provide the data that spacecraft designers need to properly design and implement fire detection in spacecraft. This investigation will also evaluate the performance of the smoke detectors currently in use aboard the space shuttle and ISS for the test materials in a microgravity environment.

Spectral indices of cardiovascular adaptations to short-term simulated microgravity exposure

Science.gov (United States)

Patwardhan, A. R.; Evans, J. M.; Berk, M.; Grande, K. J.; Charles, J. B.; Knapp, C. F.

1995-01-01

We investigated the effects of exposure to microgravity on the baseline autonomic balance in cardiovascular regulation using spectral analysis of cardiovascular variables measured during supine rest. Heart rate, arterial pressure, radial flow, thoracic fluid impedance and central venous pressure were recorded from nine volunteers before and after simulated microgravity, produced by 20 hours of 6 degrees head down bedrest plus furosemide. Spectral powers increased after simulated microgravity in the low frequency region (centered at about 0.03 Hz) in arterial pressure, heart rate and radial flow, and decreased in the respiratory frequency region (centered at about 0.25 Hz) in heart rate. Reduced heart rate power in the respiratory frequency region indicates reduced parasympathetic influence on the heart. A concurrent increase in the low frequency power in arterial pressure, heart rate, and radial flow indicates increased sympathetic influence. These results suggest that the baseline autonomic balance in cardiovascular regulation is shifted towards increased sympathetic and decreased parasympathetic influence after exposure to short-term simulated microgravity.

Cellular and molecular aspects of plant adaptation to microgravity

Science.gov (United States)

Kordyum, Elizabeth; Kozeko, Liudmyla

2016-07-01

Elucidation of the range and mechanisms of the biological effects of microgravity is one of the urgent fundamental tasks of space and gravitational biology. The absence of forbidding on plant growth and development in orbital flight allows studying different aspects of plant adaptation to this factor that is directly connected with development of the technologies of bioregenerative life-support systems. Microgravity belongs to the environmental factors which cause adaptive reactions at the cellular and molecular levels in the range of physiological responses in the framework of genetically determined program of ontogenesis. It is known that cells of a multicellular organism not only take part in reactions of the organism but also carry out processes that maintain their integrity. In light of these principles, the problem of identification of biochemical, physiological and structural patterns that can have adaptive significance at the cellular and molecular levels in real and simulated microgravity is considered. It is pointed that plant cell responses in microgravity and under clinorotation vary according to growth phase, physiological state, and taxonomic position of the object. At the same time, the responses have, to some degree, a similar character reflecting the changes in the cell organelle functional load. The maintenance of the plasmalemma fluidity at the certain level, an activation of both the antioxidant system and expression of HSP genes, especially HSP70, under increasing reactive oxygen species, lipid peroxidation intensity and alteration in protein homeostasis, are a strategic paradigm of rapid (primary) cell adaptation to microgravity. In this sense, biological membranes, especially plasmalemma, and their properties and functions may be considered as the most sensitive indicators of the influence of gravity or altered gravity on a cell. The plasmalemma lipid bilayer is a border between the cell internal content and environment, so it is a mediator

Human posture experiments under water: ways of applying the findings to microgravity

Science.gov (United States)

Dirlich, Thomas

For the design and layout human spacecraft interiors the Neutral Body Posture (NBP) in micro-gravity is of great importance. The NBP has been defined as the stable, replicable and nearly constant posture the body "automatically" assumes when a human relaxes in microgravity. Furthermore the NBP, as published, suggests that there is one standard neutral posture for all individuals. Published experiments from space, parabolic flights and under water on the other hand show strong inter-individual variations of neutral (relaxed) postures. This might originate from the quite small sample sizes of subjects analyzed or the different experiment conditions, e. g. space and under water. Since 2008 a collaborative research project focussing on human postures and motions in microgravity has been ongoing at the Technische Univer-sitüt München (TUM). This collaborative effort is undertaken by the Institute of Astronautics a (LRT) and the Institute of Ergonomics (LfE). Several test campaigns have been conducted in simulated microgravity under water using a specially designed standardized experiment setup. Stereo-metric HD video footage and anthropometric data from over 50 subjects (female and male) has been gathered in over 80 experiments. The video data is analyzed using PCMAN software, developed by the LfE, resulting in a 3D volumetric CAD-based model of each subject and posture. Preliminary and ongoing analysis of the data offer evidence for the existence of intra-individually constant neutral postures, as well as continuously recurring relaxation strate-gies. But as with the data published prior the TUM experiments show quite a large variation of inter-individual postures. These variation might be induced or influenced by the special environmental conditions in the underwater experiment. Thus in present paper ways of stan-dardizing data and applying the findings gathered under water to real microgravity are being discussed. The following influences stemming from the

Contact Angle Influence on Geysering Jets in Microgravity Investigated

Science.gov (United States)

Chato, David J.

2004-01-01

Microgravity poses many challenges to the designer of spacecraft tanks. Chief among these are the lack of phase separation and the need to supply vapor-free liquid or liquid-free vapor to the spacecraft processes that require fluid. One of the principal problems of phase separation is the creation of liquid jets. A jet can be created by liquid filling, settling of the fluid to one end of the tank, or even closing a valve to stop the liquid flow. Anyone who has seen a fountain knows that jets occur in normal gravity also. However, in normal gravity, the gravity controls and restricts the jet flow. In microgravity, with gravity largely absent, surface tension forces must be used to contain jets. To model this phenomenon, a numerical method that tracks the fluid motion and the surface tension forces is required. Jacqmin has developed a phase model that converts the discrete surface tension force into a barrier function that peaks at the free surface and decays rapidly away. Previous attempts at this formulation were criticized for smearing the interface. This can be overcome by sharpening the phase function, double gridding the fluid function, and using a higher-order solution for the fluid function. The solution of this equation can be rewritten as two coupled Poisson equations that also include the velocity.

Transfection of the IHH gene into rabbit BMSCs in a simulated microgravity environment promotes chondrogenic differentiation and inhibits cartilage aging.

Science.gov (United States)

Liu, Peng-Cheng; Liu, Kuan; Liu, Jun-Feng; Xia, Kuo; Chen, Li-Yang; Wu, Xing

2016-09-27

The effect of overexpressing the Indian hedgehog (IHH) gene on the chondrogenic differentiation of rabbit bone marrow-derived mesenchymal stem cells (BMSCs) was investigated in a simulated microgravity environment. An adenovirus plasmid encoding the rabbit IHH gene was constructed in vitro and transfected into rabbit BMSCs. Two large groups were used: conventional cell culture and induction model group and simulated microgravity environment group. Each large group was further divided into blank control group, GFP transfection group, and IHH transfection group. During differentiation induction, the expression levels of cartilage-related and cartilage hypertrophy-related genes and proteins in each group were determined. In the conventional model, the IHH transfection group expressed high levels of cartilage-related factors (Coll2 and ANCN) at the early stage of differentiation induction and expressed high levels of cartilage hypertrophy-related factors (Coll10, annexin 5, and ALP) at the late stage. Under the simulated microgravity environment, the IHH transfection group expressed high levels of cartilage-related factors and low levels of cartilage hypertrophy-related factors at all stages of differentiation induction. Under the simulated microgravity environment, transfection of the IHH gene into BMSCs effectively promoted the generation of cartilage and inhibited cartilage aging and osteogenesis. Therefore, this technique is suitable for cartilage tissue engineering.

A Six-DOF Buoyancy Tank Microgravity Test Bed with Active Drag Compensation

Science.gov (United States)

Sun, Chong; Chen, Shiyu; Yuan, Jianping; Zhu, Zhanxia

2017-10-01

Ground experiment under microgravity is very essential because it can verify the space enabling technologies before applied in space missions. In this paper, a novel ground experiment system that can provide long duration, large scale and high microgravity level for the six degree of freedom (DOF) spacecraft trajectory tracking is presented. In which, the most gravity of the test body is balanced by the buoyancy, and the small residual gravity is offset by the electromagnetic force. Because the electromagnetic force on the test body can be adjusted in the electromagnetic system, it can significantly simplify the balancing process using the proposed microgravity test bed compared to the neutral buoyance system. Besides, a novel compensation control system based on the active disturbance rejection control (ADRC) method is developed to estimate and compensate the water resistance online, in order to improve the fidelity of the ground experiment. A six-DOF trajectory tracking in the microgravity system is applied to testify the efficiency of the proposed compensation controller, and the experimental simulation results are compared to that obtained using the classic proportional-integral-derivative (PID) method. The simulation results demonstrated that, for the six-DOF motion ground experiment, the microgravity level can reach to 5 × 10-4 g. And, because the water resistance has been estimated and compensated, the performance of the presented controller is much better than the PID controller. The presented ground microgravity system can be applied in on-orbit service and other related technologies in future.

Host-Microbe Interactions in Microgravity: Assessment and Implications

Directory of Open Access Journals (Sweden)

Jamie S. Foster

2014-05-01

Full Text Available Spaceflight imposes several unique stresses on biological life that together can have a profound impact on the homeostasis between eukaryotes and their associated microbes. One such stressor, microgravity, has been shown to alter host-microbe interactions at the genetic and physiological levels. Recent sequencing of the microbiomes associated with plants and animals have shown that these interactions are essential for maintaining host health through the regulation of several metabolic and immune responses. Disruptions to various environmental parameters or community characteristics may impact the resiliency of the microbiome, thus potentially driving host-microbe associations towards disease. In this review, we discuss our current understanding of host-microbe interactions in microgravity and assess the impact of this unique environmental stress on the normal physiological and genetic responses of both pathogenic and mutualistic associations. As humans move beyond our biosphere and undergo longer duration space flights, it will be essential to more fully understand microbial fitness in microgravity conditions in order to maintain a healthy homeostasis between humans, plants and their respective microbiomes.

Host-microbe interactions in microgravity: assessment and implications.

Science.gov (United States)

Foster, Jamie S; Wheeler, Raymond M; Pamphile, Regine

2014-05-26

Spaceflight imposes several unique stresses on biological life that together can have a profound impact on the homeostasis between eukaryotes and their associated microbes. One such stressor, microgravity, has been shown to alter host-microbe interactions at the genetic and physiological levels. Recent sequencing of the microbiomes associated with plants and animals have shown that these interactions are essential for maintaining host health through the regulation of several metabolic and immune responses. Disruptions to various environmental parameters or community characteristics may impact the resiliency of the microbiome, thus potentially driving host-microbe associations towards disease. In this review, we discuss our current understanding of host-microbe interactions in microgravity and assess the impact of this unique environmental stress on the normal physiological and genetic responses of both pathogenic and mutualistic associations. As humans move beyond our biosphere and undergo longer duration space flights, it will be essential to more fully understand microbial fitness in microgravity conditions in order to maintain a healthy homeostasis between humans, plants and their respective microbiomes.

NASA Microgravity Science Competition for High-school-aged Student Teams

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DeLombard, Richard; Stocker, Dennis; Hodanbosi, Carol; Baumann, Eric

2002-01-01

NASA participates in a wide variety of educational activities including competitive events. There are competitive events sponsored by NASA and student teams which are mentored by NASA centers. This participation by NASA in public forums serves to bring the excitement of aerospace science to students and educators. A new competition for highschool-aged student teams involving projects in microgravity has completed two pilot years and will have national eligibility for teams during the 2002-2003 school year. A team participating in the Dropping In a Microgravity Environment will research the field of microgravity, develop a hypothesis, and prepare a proposal for an experiment to be conducted in a microgravity drop tower facility. A team of NASA scientists and engineers will select the top proposals and those teams will then design and build their experiment apparatus. When the experiment apparatus are completed, team representatives will visit NASA Glenn in Cleveland, Ohio for operation of their facility and participate in workshops and center tours. Presented in this paper will be a description of DIME, an overview of the planning and execution of such a program, results from the first two pilot years, and a status of the first national competition.

Computational and Experimental Study of Energetic Materials in a Counterflow Microgravity Environment

Science.gov (United States)

Takahashi, Fumiaki (Technical Monitor); Urban, David (Technical Monitor); Smooke, M. D.; Parr, T. P.; Hanson-Parr, D. M.; Yetter, R. A.; Risha, G.

2004-01-01

Counterflow diffusion flames are studied for various fuels flowing against decomposition products from solid ammonium perchlorate (AP) pellets in order to obtain fundamental understanding of composite propellant flame structure and chemistry. We illustrate this approach through a combined experimental and numerical study of a fuel mixture consisting of C2H4 CO + H2, and C2H2 + C2H4 flowing against solid AP. For these particular AP-fuel systems, the resulting flame zone simulates the various flame structures that are ex+ to exist between reaction products from Ap crystals and a hydrocarbon binder. As in all our experimental studies, quantitative species and temperature profiles have been measured between the fuel exit and AP surface. Species measured included CN, NH, NO, OH, N2, CO2, CO, H2, CO, HCl, and H2O. Temperature was measured using a thermocouple at the exit, spontaneous Raman scattering measurements throughout the flame, OH rotational population distributions, and NO vibrational population distributions. The burning rate of AP was also measured as a function of strain rate, given by the separation distance between the AP surface and the gaseous hydrocarbon fuel tube exit plane. This distance was nominally set at 5 mm, although studies have been performed for variations in separation distance. The measured 12 scalars are compared with predictions from a detailed gas-phase kinetics model consisting of 86 species and 531 reactions. Model predictions are found to be in good agreement with experiment and illustrate the type of kinetic features that may be expected to occur in propellants when AP particle size distributions are varied. Furthermore, the results constitute the continued development of a necessary database and validation of a comprehensive model for studying more complex AP-solid fuel systems in microgravity. Exploratory studies have also been performed with liquid and solid fuels at normal gravity. Because of melting (and hence dripping) and deep

Evaluation of upper body muscle activity during cardiopulmonary resuscitation performance in simulated microgravity

Science.gov (United States)

Waye, A. B.; Krygiel, R. G.; Susin, T. B.; Baptista, R.; Rehnberg, L.; Heidner, G. S.; de Campos, F.; Falcão, F. P.; Russomano, T.

2013-09-01

Performance of efficient single-person cardiopulmonary resuscitation (CPR) is vital to maintain cardiac and cerebral perfusion during the 2-4 min it takes for deployment of advanced life support during a space mission. The aim of the present study was to investigate potential differences in upper body muscle activity during CPR performance at terrestrial gravity (+1Gz) and in simulated microgravity (μG). Muscle activity of the triceps brachii, erector spinae, rectus abdominis and pectoralis major was measured via superficial electromyography in 20 healthy male volunteers. Four sets of 30 external chest compressions (ECCs) were performed on a mannequin. Microgravity was simulated using a body suspension device and harness; the Evetts-Russomano (ER) method was adopted for CPR performance in simulated microgravity. Heart rate and perceived exertion via Borg scores were also measured. While a significantly lower depth of ECCs was observed in simulated microgravity, compared with +1Gz, it was still within the target range of 40-50 mm. There was a 7.7% decrease of the mean (±SEM) ECC depth from 48 ± 0.3 mm at +1Gz, to 44.3 ± 0.5 mm during microgravity simulation (p < 0.001). No significant difference in number or rate of compressions was found between the two conditions. Heart rate displayed a significantly larger increase during CPR in simulated microgravity than at +1Gz, the former presenting a mean (±SEM) of 23.6 ± 2.91 bpm and the latter, 76.6 ± 3.8 bpm (p < 0.001). Borg scores were 70% higher post-microgravity compressions (17 ± 1) than post +1Gz compressions (10 ± 1) (p < 0.001). Intermuscular comparisons showed the triceps brachii to have significantly lower muscle activity than each of the other three tested muscles, in both +1Gz and microgravity. As shown by greater Borg scores and heart rate increases, CPR performance in simulated microgravity is more fatiguing than at +1Gz. Nevertheless, no significant difference in muscle activity between conditions

Powder agglomeration in a microgravity environment

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Cawley, James D.

1994-01-01

This is the final report for NASA Grant NAG3-755 entitled 'Powder Agglomeration in a Microgravity Environment.' The research program included both two types of numerical models and two types of experiments. The numerical modeling included the use of Monte Carlo type simulations of agglomerate growth including hydrodynamic screening and molecular dynamics type simulations of the rearrangement of particles within an agglomerate under a gravitational field. Experiments included direct observation of the agglomeration of submicron alumina and indirect observation, using small angle light scattering, of the agglomeration of colloidal silica and aluminum monohydroxide. In the former class of experiments, the powders were constrained to move on a two-dimensional surface oriented to minimize the effect of gravity. In the latter, some experiments involved mixture of suspensions containing particles of opposite charge which resulted in agglomeration on a very short time scale relative to settling under gravity.

Effect of Oenothera odorata Root Extract on Microgravity and Disuse-Induced Muscle Atrophy.

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Lee, Yong-Hyeon; Seo, Dong-Hyun; Park, Ji-Hyung; Kabayama, Kazuya; Opitz, Joerg; Lee, Kwang Ho; Kim, Han-Sung; Kim, Tack-Joong

2015-01-01

Muscle atrophy, a reduction of muscle mass, strength, and volume, results from reduced muscle use and plays a key role in various muscular diseases. In the microgravity environment of space especially, muscle atrophy is induced by muscle inactivity. Exposure to microgravity induces muscle atrophy through several biological effects, including associations with reactive oxygen species (ROS). This study used 3D-clinostat to investigate muscle atrophy caused by oxidative stress in vitro, and sciatic denervation was used to investigate muscle atrophy in vivo. We assessed the effect of Oenothera odorata root extract (EVP) on muscle atrophy. EVP helped recover cell viability in C2C12 myoblasts exposed to microgravity for 24 h and delayed muscle atrophy in sciatic denervated mice. However, the expressions of HSP70, SOD1, and ceramide in microgravity-exposed C2C12 myoblasts and in sciatic denervated mice were either decreased or completely inhibited. These results suggested that EVP can be expected to have a positive effect on muscle atrophy by disuse and microgravity. In addition, EVP helped characterize the antioxidant function in muscle atrophy.

The effect of microgravity on tissue structure and function of rat testis

Directory of Open Access Journals (Sweden)

Ye Ding

2011-12-01

Full Text Available To explore whether an environment of weightlessness will cause damage to the reproductive system of animals, we used the tail-suspension model to simulate microgravity, and investigated the effect of microgravity on the tissue structure and function of the testis in sexually mature male rats. Forty-eight male Wistar rats weighing 200-250 g were randomly assigned to three groups (N = 16 each: control, tail traction, and tail suspension. After the rats were suspended for 7 or 14 days, morphological changes of testis were evaluated by histological and electron microscopic methods. The expression of HSP70, bax/bcl-2 and AR (androgen receptor in testis was measured by immunohistochemistry. Obvious pathological lesions were present in the testis after the rats were suspended for 7 or 14 days. We detected overexpression of HSP70 and an increase of apoptotic cells, which may have contributed to the injury to the testis. The expression of AR, as an effector molecule in the testis, was significantly decreased in the suspended groups compared to control (P < 0.01. We also observed that, with a longer time of suspension, the aforementioned pathological damage became more serious and some pathological injury to the testis was irreversible. The results demonstrated that a short- or medium-term microgravity environment could lead to severe irreversible damage to the structure of rat testis.

Evaluation of a novel basic life support method in simulated microgravity.

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Rehnberg, Lucas; Russomano, Thaws; Falcão, Felipe; Campos, Fabio; Everts, Simon N

2011-02-01

If a cardiac arrest occurs in microgravity, current emergency protocols aim to treat patients via a medical restraint system within 2-4 min. It is vital that crewmembers have the ability to perform single-person cardiopulmonary resuscitation (CPR) during this period, allowing time for advanced life support to be deployed. The efficacy of the Evetts-Russomano (ER) method has been tested in 22 s of microgravity in a parabolic flight and has shown that external chest compressions (ECC) and mouth-to-mouth ventilation are possible. There were 21 male subjects who performed both the ER method in simulated microgravity via full body suspension and at +1 Gz. The CPR mannequin was modified to provide accurate readings for ECC depth and a metronome to set the rate at 100 bpm. Heart rate, rate of perceived exertion, and angle of arm flexion were measured with an ECG, elbow electrogoniometers, and Borg scale, respectively. The mean (+/- SD) depth of ECC in simulated microgravity was lower in each of the 3 min compared to +1 G2. The ECC depth (45.7 +/- 2.7 mm, 42.3 +/- 5.5 mm, and 41.4 +/- 5.9 mm) and rate (104.5 +/- 5.2, 105.2 +/- 4.5, and 102.4 +/- 6.6 compressions/min), however, remained within CPR guidelines during simulated microgravity over the 3-min period. Heart rate, perceived exertion, and elbow flexion of both arms increased using the ER method. The ER method can provide adequate depth and rate of ECC in simulated microgravity for 3 min to allow time to deploy a medical restraint system. There is, however, a physiological cost associated with it and a need to use the flexion of the arms to compensate for the lack of weight.

Exposure to microgravity for 30 days onboard Bion M1 caused muscle atrophy and impaired regeneration in murine femoral Quadriceps

Science.gov (United States)

Radugina, E. A.; Almeida, E. A. C.; Blaber, E.; Poplinskaya, V. A.; Markitantova, Y. V.; Grigoryan, E. N.

2018-02-01

immunolocalization, as well as Myogenin expression analysis. In addition, we have detected positive nuclear immunolocalization of c-Jun and c-Myc proteins indicating their sensitivity to changes in gravitational loading in a given model. In summary, long-term spaceflight in microgravity caused significant atrophy and degeneration of the femoral Quadriceps muscle group, and it may interfere with muscle regenerative processes by inducing apoptosis in newly-formed myofibrils during their differentiation phase.

Microgravity-Enhanced Stem Cell Selection

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Claudio, Pier Paolo; Valluri, Jagan

2011-01-01

Stem cells, both embryonic and adult, promise to revolutionize the practice of medicine in the future. In order to realize this potential, a number of hurdles must be overcome. Most importantly, the signaling mechanisms necessary to control the differentiation of stem cells into tissues of interest remain to be elucidated, and much of the present research on stem cells is focused on this goal. Nevertheless, it will also be essential to achieve large-scale expansion and, in many cases, assemble cells in 3D as transplantable tissues. To this end, microgravity analog bioreactors can play a significant role. Microgravity bioreactors were originally conceived as a tool to study the cellular responses to microgravity. However, the technology can address some of the shortcomings of conventional cell culture systems; namely, the deficiency of mass transport in static culture and high mechanical shear forces in stirred systems. Unexpectedly, the conditions created in the vessel were ideal for 3D cell culture. Recently, investigators have demonstrated the capability of the microgravity bioreactors to expand hematopoietic stem cells compared to static culture, and facilitate the differentiation of umbilical cord stem cells into 3D liver aggregates. Stem cells are capable of differentiating into functional cells. However, there are no reliable methods to induce the stem cells to form specific cells or to gain enough cells for transplantation, which limits their application in clinical therapy. The aim of this study is to select the best experimental setup to reach high proliferation levels by culturing these cells in a microgravity-based bioreactor. In typical cell culture, the cells sediment to the bottom surface of their container and propagate as a one-cell-layer sheet. Prevention of such sedimentation affords the freedom for self-assembly and the propagation of 3D tissue arrays. Suspension of cells is easily achievable using stirred technologies. Unfortunately, in

Effect of IR Laser on Myoblasts: Prospects of Application for Counteracting Microgravity-Induced Muscle Atrophy

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Monici, Monica; Cialdai, Francesca; Romano, Giovanni; Corsetto, Paola Antonia; Rizzo, Angela Maria; Caselli, Anna; Ranaldi, Francesco

2013-02-01

Microgravity-induced muscle atrophy is a problem of utmost importance for the impact it may have on the health and performance of astronauts. Therefore, appropriate countermeasures are needed to prevent disuse atrophy and favour muscle recovery. Muscle atrophy is characterized by loss of muscle mass and strength, and a shift in substrate utilization from fat to glucose, that leads to a reduced metabolic efficiency and enhanced fatigability. Laser therapy is already used in physical medicine and rehabilitation to accelerate muscle recovery and in sports medicine to prevent damages produced by metabolic disturbances and inflammatory reactions after heavy exercise. The aim of the research we present was to get insights on possible benefits deriving from the application of an advanced infrared laser system to counteract deficits of muscle energy metabolism and stimulate the recovery of the hypotrophic tissue. The source used was a Multiwave Locked System (MLS) laser, which combines continuous and pulsed emissions at 808 nm and 905 nm, respectively. We studied the effect of MLS treatment on morphology and energy metabolism of C2C12 cells, a widely accepted myoblast model, previously exposed to microgravity conditions modelled by a Random Positioning Machine. The MLS laser treatment was able to restore basal levels of serine/threonine protein phosphatase activity and to counteract cytoskeletal alterations and increase in glycolytic enzymes activity that occurred following the exposure to modelled microgravity. In conclusion, the results provide interesting insights for the application of infrared laser in the treatment of muscle atrophy.

Effects of Microgravity on the Formation of Aerogels

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Hunt, A. J.; Ayers, M. R.; Sibille, L.; Cronise, R. J.; Noever, D. A.

1999-01-01

This paper describes research to investigate fundamental aspects of the effects of microgravity on the formation of the microstructure of metal oxide alcogels and aerogels. We are studying the role of gravity on pore structure and gel uniformity in collaboration with Marshall Space Flight Center (MSFC) on gelling systems under microgravity conditions. While this project was just initiated in May 1998, related research performed earlier is described along with the plans and rationale for the current microgravity investigation to provide background and describe newly developing techniques that should be useful for the current gellation studies. The role of gravity in materials processing must be investigated through the study of well-mastered systems. Sol-gel processed materials are near-perfect candidates to determine the effect of gravity on the formation and growth of random clusters from hierarchies of aggregated units. The processes of hydrolysis, condensation, aggregation and gellation in the formation of alcogels are affected by gravity and therefore provide a rich system to study under microgravity conditions. Supercritical drying of the otherwise unstable wet alcogel preserves the alcogel structure produced during sol-gel processing as aerogel. Supercritically dried aerogel provides for the study of material microstructures without interference from the effects of surface tension, evaporation, and solvent flow. Aerogels are microstructured, low density open-pore solids. They have many unusual properties including: transparency, excellent thermal resistance, high surface area, very low refractive index, a dielectric constant approaching that of air, and extremely low sound velocity. Aerogels are synthesized using sol-gel processing followed by supercritical solvent extraction that leaves the original gel structure virtually intact. These studies will elucidate the effects of microgravity on the homogeneity of the microstructure and porosity of aerogel. The

Changes in Mouse Bone Turnover in Response to Microgravity

Science.gov (United States)

Cheng-Campbell, M.; Blaber, E.; Almeida, E.

2016-01-01

Mechanical unloading during spaceflight is known to adversely affect mammalian physiology. Our previous studies using the Animal Enclosure Module on short duration Shuttle missions enabled us to identify a deficit in stem cell based-tissue regeneration as being a significant concern for long-duration spaceflight. Specifically, we found that mechanical unloading in microgravity resulted in inhibition of differentiation of mesenchymal and hematopoietic stem cells in the bone marrow compartment. Also, we observed overexpression of a cell cycle arrest molecule, CDKN1a/p21, in osteoprecursor cells on the bone surface, chondroprogenitors in the articular cartilage, and in myofibers attached to bone tissue. Specifically in bone tissue during both short (15-day) and long (30-day) microgravity experiments, we observed significant loss of bone tissue and structure in both the pelvis and the femur. After 15-days of microgravity on STS-131, pelvic ischium displayed a 6.23% decrease in bone fraction (p=0.005) and 11.91% decrease in bone thickness (p=0.002). Furthermore, during long-duration spaceflight we observed onset of an accelerated aging-like phenotype and osteoarthritic disease state indicating that stem cells within the bone tissue fail to repair and regenerate tissues in a normal manner, leading to drastic tissue alterations in response to microgravity. The Rodent Research Hardware System provides the capability to investigate these effects during long-duration experiments on the International Space Station. During the Rodent Research-1 mission 10 16-week-old female C57Bl/6J mice were exposed to 37-days of microgravity. All flight animals were euthanized and frozen on orbit for future dissection. Ground (n=10) and vivarium controls (n=10) were housed and processed to match the flight animal timeline. During this study we collected pelvis, femur, and tibia from all animal groups to test the hypothesis that stem cell-based tissue regeneration is significantly altered

Characterizing parameters of Jatropha curcas cell cultures for microgravity studies

Science.gov (United States)

Vendrame, Wagner A.; Pinares, Ania

2013-06-01

evaluated in this study provide the basic ground work and pre-flight assessment needed to justify a model for microgravity studies with jatropha in vitro cell cultures. Future studies should focus on results of experiments performed with jatropha in vitro cultures in microgravity.

The Effect of Simulated Microgravity Environment of RWV Bioreactors on Surface Reactions and Adsorption of Serum Proteins on Bone-bioactive Microcarriers

Science.gov (United States)

Radin, Shula; Ducheyne, P.; Ayyaswamy, P. S.

2003-01-01

Biomimetically modified bioactive materials with bone-like surface properties are attractive candidates for use as microcarriers for 3-D bone-like tissue engineering under simulated microgravity conditions of NASA designed rotating wall vessel (RWV) bioreactors. The simulated microgravity environment is attainable under suitable parametric conditions of the RWV bioreactors. Ca-P containing bioactive glass (BG), whose stimulatory effect on bone cell function had been previously demonstrated, was used in the present study. BG surface modification via reactions in solution, resulting formation of bone-like minerals at the surface and adsorption of serum proteins is critical for obtaining the stimulatory effect. In this paper, we report on the major effects of simulated microgravity conditions of the RWV on the BG reactions surface reactions and protein adsorption in physiological solutions. Control tests at normal gravity were conducted at static and dynamic conditions. The study revealed that simulated microgravity remarkably enhanced reactions involved in the BG surface modification, including BG dissolution, formation of bone-like minerals at the surface and adsorption of serum proteins. Simultaneously, numerical models were developed to simulate the mass transport of chemical species to and from the BG surface under normal gravity and simulated microgravity conditions. The numerical results showed an excellent agreement with the experimental data at both testing conditions.

Improvement in the quality of hematopoietic prostaglandin D synthase crystals in a microgravity environment

International Nuclear Information System (INIS)

Tanaka, Hiroaki; Tsurumura, Toshiharu; Aritake, Kosuke; Furubayashi, Naoki; Takahashi, Sachiko; Yamanaka, Mari; Hirota, Erika; Sano, Satoshi; Sato, Masaru; Kobayashi, Tomoyuki; Tanaka, Tetsuo; Inaka, Koji; Urade, Yoshihiro

2011-01-01

Crystals of hematopoietic prostaglandin D synthase grown in microgravity show improved quality. Human hematopoietic prostaglandin synthase, one of the better therapeutic target enzymes for allergy and inflammation, was crystallized with 22 inhibitors and in three inhibitor-free conditions in microgravity. Most of the space-grown crystals showed better X-ray diffraction patterns than the terrestrially grown ones, indicating the advantage of a microgravity environment on protein crystallization, especially in the case of this protein

Effect of Oenothera odorata Root Extract on Microgravity and Disuse-Induced Muscle Atrophy

Directory of Open Access Journals (Sweden)

Yong-Hyeon Lee

2015-01-01

Full Text Available Muscle atrophy, a reduction of muscle mass, strength, and volume, results from reduced muscle use and plays a key role in various muscular diseases. In the microgravity environment of space especially, muscle atrophy is induced by muscle inactivity. Exposure to microgravity induces muscle atrophy through several biological effects, including associations with reactive oxygen species (ROS. This study used 3D-clinostat to investigate muscle atrophy caused by oxidative stress in vitro, and sciatic denervation was used to investigate muscle atrophy in vivo. We assessed the effect of Oenothera odorata root extract (EVP on muscle atrophy. EVP helped recover cell viability in C2C12 myoblasts exposed to microgravity for 24 h and delayed muscle atrophy in sciatic denervated mice. However, the expressions of HSP70, SOD1, and ceramide in microgravity-exposed C2C12 myoblasts and in sciatic denervated mice were either decreased or completely inhibited. These results suggested that EVP can be expected to have a positive effect on muscle atrophy by disuse and microgravity. In addition, EVP helped characterize the antioxidant function in muscle atrophy.

Microgravity: A New Tool for Basic and Applied Research in Space

Science.gov (United States)

1985-01-01

This brochure highlights selected aspects of the NASA Microgravity Science and Applications program. So that we can expand our understanding and control of physical processes, this program supports basic and applied research in electronic materials, metals, glasses and ceramics, biological materials, combustion and fluids and chemicals. NASA facilities that provide weightless environments on the ground, in the air, and in space are available to U.S. and foreign investigators representing the academic and industrial communities. After a brief history of microgravity research, the text explains the advantages and methods of performing microgravity research. Illustrations follow of equipment used and experiments preformed aboard the Shuttle and of prospects for future research. The brochure concludes be describing the program goals and the opportunities for participation.

Advanced Magnetic Materials Methods and Numerical Models for Fluidization in Microgravity and Hypogravity

Science.gov (United States)

Atwater, James; Wheeler, Richard, Jr.; Akse, James; Jovanovic, Goran; Reed, Brian

2013-01-01

To support long-duration manned missions in space such as a permanent lunar base, Mars transit, or Mars Surface Mission, improved methods for the treatment of solid wastes, particularly methods that recover valuable resources, are needed. The ability to operate under microgravity and hypogravity conditions is essential to meet this objective. The utilization of magnetic forces to manipulate granular magnetic media has provided the means to treat solid wastes under variable gravity conditions by filtration using a consolidated magnetic media bed followed by thermal processing of the solid wastes in a fluidized bed reactor. Non-uniform magnetic fields will produce a magnetic field gradient in a bed of magnetically susceptible media toward the distributor plate of a fluidized bed reactor. A correctly oriented magnetic field gradient will generate a downward direct force on magnetic media that can substitute for gravitational force in microgravity, or which may augment low levels of gravity, such as on the Moon or Mars. This approach is termed Gradient Magnetically Assisted Fluidization (G-MAFB), in which the magnitude of the force on the fluidized media depends upon the intensity of the magnetic field (H), the intensity of the field gradient (dH/dz), and the magnetic susceptibility of the media. Fluidized beds based on the G-MAFB process can operate in any gravitational environment by tuning the magnetic field appropriately. Magnetic materials and methods have been developed that enable G-MAFB operation under variable gravity conditions.

Development of Methodology to Gather Seated Anthropometry Data in a Microgravity Environment

Science.gov (United States)

Rajulu, Sudhakar; Young, Karen; Mesloh, Miranda

2010-01-01

The Constellation Program is designing a new vehicle based off of new anthropometric requirements. These requirements specify the need to account for a spinal elongation factor for anthropometric measurements involving the spine, such as eye height and seated height. However, to date there is no data relating spinal elongation to a seated posture. Only data relating spinal elongation to stature has been collected in microgravity. Therefore, it was proposed to collect seated height in microgravity to provide the Constellation designers appropriate data for their analyses. This document will describe the process in which the best method to collect seated height in microgravity was developed.

The Strata-l Experiment on Microgravity Regolith Segregation

Science.gov (United States)

Fries, M.; Abell, P.; Brisset, J.; Britt, D.; Colwell, J.; Durda, D.; Dove, A.; Graham, L.; Hartzell, C.; John, K.;

Genome-wide analysis of the Pho regulon in a pstCA mutant of Citrobacter rodentium.

Directory of Open Access Journals (Sweden)

Catherine Cheng

Full Text Available The phosphate-specific transport operon, pstSCAB-phoU, of Gram-negative bacteria is an essential part of the Pho regulon. Its key roles are to encode a high-affinity inorganic phosphate transport system and to prevent activation of PhoB in phosphate-rich environments. In general, mutations in pstSCAB-phoU lead to the constitutive expression of the Pho regulon. Previously, we constructed a pstCA deletion mutant of Citrobacter rodentium and found it to be attenuated for virulence in mice, its natural host. This attenuation was dependent on PhoB or PhoB-regulated gene(s because a phoB mutation restored virulence for mice to the pstCA mutant. To investigate how downstream genes may contribute to the virulence of C. rodentium, we used microarray analysis to investigate global gene expression of C. rodentium strain ICC169 and its isogenic pstCA mutant when grown in phosphate-rich medium. Overall 323 genes of the pstCA mutant were differentially expressed by at least 1.5-fold compared to the wild-type C. rodentium. Of these 145 were up-regulated and 178 were down-regulated. Differentially expressed genes included some involved in phosphate homoeostasis, cellular metabolism and protein metabolism. A large number of genes involved in stress responses and of unknown function were also differentially expressed, as were some virulence-associated genes. Up-regulated virulence-associated genes in the pstCA mutant included that for DegP, a serine protease, which appeared to be directly regulated by PhoB. Down-regulated genes included those for the production of the urease, flagella, NleG8 (a type III-secreted protein and the tad focus (which encodes type IVb pili in Yersinia enterocolitica. Infection studies using C57/BL6 mice showed that DegP and NleG8 play a role in bacterial virulence. Overall, our study provides evidence that Pho is a global regulator of gene expression in C. rodentium and indicates the presence of at least two previously unrecognized

DNA repair in modeled microgravity: Double strand break rejoining activity in human lymphocytes irradiated with γ-rays

International Nuclear Information System (INIS)

Mognato, Maddalena; Girardi, Cristina; Fabris, Sonia; Celotti, Lucia

2009-01-01

Cell response to ionising radiation depends, besides on genetic and physiological features of the biological systems, on environmental conditions occurring during DNA repair. Many data showed that microgravity, experienced by astronauts during space flights or modeled on Earth, causes apoptosis, cytoskeletal alteration, cell growth inhibition, increased frequency of mutations and chromosome aberrations. In this study, we analysed the progression of the rejoining of double strand breaks (DSBs) in human peripheral blood lymphocytes (PBLs) irradiated with γ-rays and incubated in static condition (1g) or in modeled microgravity (MMG). γ-H2AX foci formation and disappearance, monitored during the repair incubation, showed that the kinetics of DSBs rejoining was different in the two gravity conditions. The fraction of foci-positive cells decreased slower in MMG than in 1g at 6 and 24 h after irradiation (P < 0.01) and the mean number of γ-H2AX foci per nucleus was significantly higher in MMG than in 1g at the same time-points (P < 0.001). In the same samples we determined apoptotic level and the rate of DSB rejoining during post-irradiation incubation. A significant induction of apoptosis was observed in MMG at 24 h after irradiation (P < 0.001), whereas at shorter times the level of apoptosis was slightly higher in MMG respect to 1g. In accordance with the kinetics of γ-H2AX foci, the slower rejoining of radiation-induced DSBs in MMG was observed by DNA fragmentation analyses during the repair incubation; the data of pulsed-field gel electrophoresis assay showed that the fraction of DNA released in the gel was significantly higher in PBL incubated in MMG after irradiation with respect to cells maintained in 1g. Our results provide evidences that MMG incubation during DNA repair delayed the rate of radiation-induced DSB rejoining, and increased, as a consequence, the genotoxic effects of ionising radiation.

DNA repair in modeled microgravity: Double strand break rejoining activity in human lymphocytes irradiated with {gamma}-rays

Energy Technology Data Exchange (ETDEWEB)

Mognato, Maddalena, E-mail: maddalena.mognato@unipd.it [Dipartimento di Biologia, Universita di Padova, via U. Bassi 58 B, 35121 Padova (Italy); Girardi, Cristina; Fabris, Sonia [Dipartimento di Biologia, Universita di Padova, via U. Bassi 58 B, 35121 Padova (Italy); Celotti, Lucia [Dipartimento di Biologia, Universita di Padova, via U. Bassi 58 B, 35121 Padova (Italy); Laboratori Nazionali di Legnaro, INFN, Padova (Italy)

2009-04-26

Cell response to ionising radiation depends, besides on genetic and physiological features of the biological systems, on environmental conditions occurring during DNA repair. Many data showed that microgravity, experienced by astronauts during space flights or modeled on Earth, causes apoptosis, cytoskeletal alteration, cell growth inhibition, increased frequency of mutations and chromosome aberrations. In this study, we analysed the progression of the rejoining of double strand breaks (DSBs) in human peripheral blood lymphocytes (PBLs) irradiated with {gamma}-rays and incubated in static condition (1g) or in modeled microgravity (MMG). {gamma}-H2AX foci formation and disappearance, monitored during the repair incubation, showed that the kinetics of DSBs rejoining was different in the two gravity conditions. The fraction of foci-positive cells decreased slower in MMG than in 1g at 6 and 24 h after irradiation (P < 0.01) and the mean number of {gamma}-H2AX foci per nucleus was significantly higher in MMG than in 1g at the same time-points (P < 0.001). In the same samples we determined apoptotic level and the rate of DSB rejoining during post-irradiation incubation. A significant induction of apoptosis was observed in MMG at 24 h after irradiation (P < 0.001), whereas at shorter times the level of apoptosis was slightly higher in MMG respect to 1g. In accordance with the kinetics of {gamma}-H2AX foci, the slower rejoining of radiation-induced DSBs in MMG was observed by DNA fragmentation analyses during the repair incubation; the data of pulsed-field gel electrophoresis assay showed that the fraction of DNA released in the gel was significantly higher in PBL incubated in MMG after irradiation with respect to cells maintained in 1g. Our results provide evidences that MMG incubation during DNA repair delayed the rate of radiation-induced DSB rejoining, and increased, as a consequence, the genotoxic effects of ionising radiation.

Definition of a second Bacillus subtilis pur regulon comprising the pur and xpt-pbuX operons plus pbuG, nupG (yxjA), and pbuE (ydhL)

DEFF Research Database (Denmark)

Johansen, L.E.; Nygaard, P.; Lassen, C.

2003-01-01

In Bacillus subtilis expression of genes or operons encoding enzymes and other proteins involved in purine synthesis is affected by purine bases and nucleosides in the growth medium. The genes belonging to the PurR regulon (purR, purA, glyA, guaC, pbuO, pbuG, and the pur, yqhZ-folD, and xpt...

Straight Ahead in Microgravity

Science.gov (United States)

Wood, S. J.; Vanya, R. D.; Clement, G.

2014-01-01

This joint ESA-NASA study will address adaptive changes in spatial orientation related to the subjective straight ahead, and the use of a vibrotactile sensory aid to reduce perceptual errors. The study will be conducted before and after long-duration expeditions to the International Space Station (ISS) to examine how spatial processing of target location is altered following exposure to microgravity. This project specifically addresses the sensorimotor research gap "What are the changes in sensorimotor function over the course of a mission?" Six ISS crewmembers will be requested to participate in three preflight sessions (between 120 and 60 days prior to launch) and then three postflight sessions on R+0/1 day, R+4 +/-2 days, and R+8 +/-2 days. The three specific aims include: (a) fixation of actual and imagined target locations at different distances; (b) directed eye and arm movements along different spatial reference frames; and (c) the vestibulo-ocular reflex during translation motion with fixation targets at different distances. These measures will be compared between upright and tilted conditions. Measures will then be compared with and without a vibrotactile sensory aid that indicates how far one has tilted relative to the straight-ahead direction. The flight study was been approved by the medical review boards and will be implemented in the upcoming Informed Crew Briefings to solicit flight subject participation. Preliminary data has been recorded on 6 subjects during parabolic flight to examine the spatial coding of eye movements during roll tilt relative to perceived orientations while free-floating during the microgravity phase of parabolic flight or during head tilt in normal gravity. Binocular videographic recordings obtained in darkness allowed us to quantify the mean deviations in gaze trajectories along both horizontal and vertical coordinates relative to the aircraft and head orientations. During some parabolas, a vibrotactile sensory aid provided

Fish Inner Ear Otolith Growth Under Real Microgravity (Spaceflight) and Clinorotation

Science.gov (United States)

Anken, Ralf; Brungs, Sonja; Grimm, Dennis; Knie, Miriam; Hilbig, Reinhard

2016-06-01

Using late larval stages of cichlid fish ( Oreochromis mossambicus) we have shown earlier that the biomineralization of otoliths is adjusted towards gravity by means of a neurally guided feedback loop. Centrifuge experiments, e.g., revealed that increased gravity slows down otolith growth. Microgravity thus should yield an opposite effect, i.e., larger than normal otoliths. Consequently, late larval cichlids (stage 14, vestibular system operational) were subjected to real microgravity during the 12 days FOTON-M3 spaceflight mission (OMEGAHAB-hardware). Controls were kept at 1 g on ground within an identical hardware. Animals of another batch were subsequently clinorotated within a submersed fast-rotating clinostat with one axis of rotation (2d-clinostat), a device regarded to simulate microgravity. Temperature and light conditions were provided in analogy to the spaceflight experiment. Controls were maintained at 1 g within the same aquarium. After all experiments, animals had reached late stage 21 (fish can swim freely). Maintenance under real microgravity during spaceflight resulted in significantly larger than normal otoliths (both lapilli and sagittae, involved in sensing gravity and the hearing process, respectively). This result is fully in line with an earlier spaceflight study in the course of which otoliths from late-staged swordtails Xiphophorus helleri were analyzed. Clinorotation resulted in larger than 1 g sagittae. However, no effect on lapilli was obtained. Possibly, an effect was present but too light to be measurable. Overall, spaceflight obviously induces an adaptation of otolith growth, whereas clinorotation does not fully mimic conditions of microgravity regarding late larval cichlids.

Altered TNF-Alpha, Glucose, Insulin and Amino Acids in Islets Langerhans Cultured in a Microgravity Model System

Science.gov (United States)

Tobin, Brian W.; Leeper-Woodford, Sandra K.; Hashemi, Brian B.; Smith, Scott M.; Sams, Clarence F.

2001-01-01

The present studies were designed to determine effects of a microgravity model system upon lipopolysaccharide (LPS) stimulated tumor necrosis factor alpha (TNF-alpha) activity and indices of insulin and fuel homeostasis of pancreatic islets of Langerhans. Islets (1726+/-1 17,150 u IEU) from Wistar Furth rats were treated as: 1) HARV (High Aspect Ratio Vessel cell culture) , 2) HARV plus LPS, 3) static culture, 4) static culture plus LPS. TNF-alpha (L929 cytotoxicity assay) was significantly increased in LPS-induced HARV and static cultures, yet the increase was more pronounced in the static culture group (palpha production of pancreatic islets of Langerhans, favoring a lesser TNF activity in the HARV. These alterations in fuel homeostasis may be promulgated by gravity averaged cell culture methods or by three dimensional cell assembly.

Fiscal 1998 research report on the basic study on the effect of microgravity on living individuals; Bisho juryoku no seibutsu kotai ni taisuru eikyo no kiso kenkyu 1998 nendo chosa hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

In order to clarify the effect of microgravity on vital functions and organisms at a cell level, this research studies the molecular biological response function of higher animals, the gravity acceptable mechanism of single-cell organisms, the effect of gravity on geotaxis of insects, measurement of monoamine system neurotransmitters of rat hippocampus by dialysis in a brain and the effect of microgravity on it, the effect of microgravity on water and bone metabolism functions and immunity function, and the analysis of BZ reaction as a simple model of vital reaction. The themes of the research are as follows: the effect of microgravity environment on cell fusion, the analysis of gravity acceptable mechanisms of single-cell organisms, the effect of oriental medical treatment on bone metabolism anomaly of mouses under microgravity environment, the effect of oriental medical treatment on change in physiological function under microgravity environment, the effect of microgravity environment on immunity systems, the effect of gravity on cell activities, the effect of a gravity field on chemical oscillation reaction, and the effect of gravity on geotaxis of insects. (NEDO)

DARTFire Sees Microgravity Fires in a New Light--Large Data Base of Images Obtained

Science.gov (United States)

Olson, Sandra L.; Hegde, Uday; Altenkirch, Robert A.; Bhatacharjee, Subrata

1999-01-01

The recently completed DARTFire sounding rocket microgravity combustion experiment launched a new era in the imaging of flames in microgravity. DARTFire stands for "Diffusive and Radiative Transport in Fires," which perfectly describes the two primary variables--diffusive flow and radiation effects--that were studied in the four launches of this program (June 1996 to September 1997). During each launch, two experiments, which were conducted simultaneously during the 6 min of microgravity, obtained results as the rocket briefly exited the Earth s atmosphere.

The components of the unique Zur regulon of Cupriavidus metallidurans mediate cytoplasmic zinc handling.

Science.gov (United States)

Bütof, Lucy; Schmidt-Vogler, Christopher; Herzberg, Martin; Große, Cornelia; Nies, Dietrich H

2017-08-14

Zinc is an essential trace element and at the same time it is toxic at high concentrations. In the beta-proteobacterium Cupriavidus metallidurans the highly efficient removal of surplus zinc from the periplasm is responsible for its outstanding metal resistance. Rather than having a typical Zur-dependent, high-affinity ATP-binding cassette transporter of the ABC protein superfamily for zinc uptake at low concentrations, C. metallidurans instead has the secondary zinc importer ZupT of the ZRT/IRT (ZIP) family. It is important to understand, therefore, how this zinc-resistant bacterium copes when it is exposed to low zinc concentrations. Members of the Zur regulon in C. metallidurans were identified by comparing the transcriptomes of a Δ zur mutant and its parent strain. The consensus sequence of the Zur-binding box was derived for the zupTp promoter-regulatory region using a truncation assay. The motif was used to predict possible Zur-boxes upstream of Zur regulon members. Binding of Zur to these boxes was confirmed. Two Zur-boxes upstream of the cobW 1 gene, encoding a putative zinc chaperone, proved to be required for complete repression of cobW 1 and its downstream genes in cells cultivated in mineral salts medium. A Zur box upstream of each of zur-cobW 2 , cobW 3 and zupT permitted low-expression level of these genes plus their up-regulation under zinc starvation conditions. This demonstrates a compartmentalization of zinc homeostasis in C. metallidurans with the periplasm being responsible for removal of surplus zinc and cytoplasmic components for management of zinc as an essential co-factor, with both compartments connected by ZupT. Importance Elucidating zinc homeostasis is necessary to understand both host-pathogen interactions and performance of free-living bacteria in their natural environment. Escherichia coli acquires zinc under low zinc concentrations by the Zur-controlled ZnuABC importer of the ABC superfamily, and this was also the paradigm for other

FY1994 annual report on the advanced combustion science in microgravity field

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-03-01

Researches were implemented continuously from the previous year on combustion equipment which enables advanced combustion technologies by studying combustion in a microgravity field, for the purpose of preventing environmental pollution caused by diversification of energy sources and exhaust gasses. In joint studies with NASA, research was conducted at both ends concerning the interaction of fuel droplets in a microgravity field; namely, high pressure combustion of binary fuel sprays at NASA against interaction in high pressure spray combustion of binary fuel at Japan side, and ignition and flame spread in microgravity field at NASA against combustion characteristics of organic solid fuels at Japan side. In fiscal 1994, in addition to the test equipment built in the previous year, a fuel droplet combustion test device was manufactured, as were a gas sampling and analyzing device, particle speed measuring device, and laser induced fluorescence measuring device. The tests using these measuring devices and microgravity test equipment were carried out 112 times, thereby establishing the measuring method of flame structure which was an objective of the present year. (NEDO)

Effect of microgravity on an animal-bacteria symbiosis

Data.gov (United States)

National Aeronautics and Space Administration — Spaceflight imposes numerous adaptive challenges for terrestrial life. The reduction in gravity or microgravity represents a novel environment that can disrupt...

Space microgravity drives transdifferentiation of human bone marrow-derived mesenchymal stem cells from osteogenesis to adipogenesis.

Science.gov (United States)

Zhang, Cui; Li, Liang; Jiang, Yuanda; Wang, Cuicui; Geng, Baoming; Wang, Yanqiu; Chen, Jianling; Liu, Fei; Qiu, Peng; Zhai, Guangjie; Chen, Ping; Quan, Renfu; Wang, Jinfu

2018-03-13

Bone formation is linked with osteogenic differentiation of mesenchymal stem cells (MSCs) in the bone marrow. Microgravity in spaceflight is known to reduce bone formation. In this study, we used a real microgravity environment of the SJ-10 Recoverable Scientific Satellite to examine the effects of space microgravity on the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs). hMSCs were induced toward osteogenic differentiation for 2 and 7 d in a cell culture device mounted on the SJ-10 Satellite. The satellite returned to Earth after going through space experiments in orbit for 12 d, and cell samples were harvested and analyzed for differentiation potentials. The results showed that space microgravity inhibited osteogenic differentiation and resulted in adipogenic differentiation, even under osteogenic induction conditions. Under space microgravity, the expression of 10 genes specific for osteogenesis decreased, including collagen family members, alkaline phosphatase ( ALP), and runt-related transcription factor 2 ( RUNX2), whereas the expression of 4 genes specific for adipogenesis increased, including adipsin ( CFD), leptin ( LEP), CCAAT/enhancer binding protein β ( CEBPB), and peroxisome proliferator-activated receptor-γ ( PPARG). In the analysis of signaling pathways specific for osteogenesis, we found that the expression and activity of RUNX2 was inhibited, expression of bone morphogenetic protein-2 ( BMP2) and activity of SMAD1/5/9 were decreased, and activity of focal adhesion kinase (FAK) and ERK-1/2 declined significantly under space microgravity. These data indicate that space microgravity plays a dual role by decreasing RUNX2 expression and activity through the BMP2/SMAD and integrin/FAK/ERK pathways. In addition, we found that space microgravity increased p38 MAPK and protein kinase B (AKT) activities, which are important for the promotion of adipogenic differentiation of hMSCs. Space microgravity significantly

Development of the Gecko (Pachydactylus turneri) Animal Model during Foton M-2 to Study Comparative Effects of Microgravity in Terrestrial and Aquatic Organisms

Science.gov (United States)

Almeida, E. A.; Roden, C.; Phillips, J. A.; Globus, R. K.; Searby, N.; Vercoutere, W.; Morey-Holton, E.; Gulimova, V.; Saveliev, S.; Tairbekov, M.;

Mass transfer processes in a post eruption hydrothermal system: Parameterisation of microgravity changes at Te Maari craters, New Zealand

Science.gov (United States)

Miller, Craig A.; Currenti, Gilda; Hamling, Ian; Williams-Jones, Glyn

2018-05-01

Fluid transfer and ground deformation at hydrothermal systems occur both as a precursor to, or as a result of, an eruption. Typically studies focus on pre-eruption changes to understand the likelihood of unrest leading to eruption; however, monitoring post-eruption changes is important for tracking the return of the system towards background activity. Here we describe processes occurring in a hydrothermal system following the 2012 eruption of Upper Te Maari crater on Mt Tongariro, New Zealand, from observations of microgravity change and deformation. Our aim is to assess the post-eruption recovery of the system, to provide a baseline for long-term monitoring. Residual microgravity anomalies of up to 92 ± 11 μGal per year are accompanied by up to 0.037 ± 0.01 m subsidence. We model microgravity changes using analytic solutions to determine the most likely geometry and source location. A multiobjective inversion tests whether the gravity change models are consistent with the observed deformation. We conclude that the source of subsidence is separate from the location of mass addition. From this unusual combination of observations, we develop a conceptual model of fluid transfer within a condensate layer, occurring in response to eruption-driven pressure changes. We find that depressurisation drives the evacuation of pore fluid, either exiting the system completely as vapour through newly created vents and fumaroles, or migrating to shallower levels where it accumulates in empty pore space, resulting in positive gravity changes. Evacuated pores then collapse, causing subsidence. In addition we find that significant mass addition occurs from influx of meteoric fluids through the fractured hydrothermal seal. Long-term combined microgravity and deformation monitoring will allow us to track the resealing and re-pressurisation of the hydrothermal system and assess what hazard it presents to thousands of hikers who annually traverse the volcano, within 2 km of the

Study about the effect of microgravity on biofunctions; Seitai kino eno bisho juryoku no eikyo ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

A study is made for the elucidation of the effect of microgravity on biofunctions. The protoplast of shiitake is exposed to microgravity and then cultured, and a significant difference occurs. The rate of colony formation by cell fusion in the test sector is found to be two times higher than that in the control sector. When swimming ciliates which are unicellular are suddenly exposed to microgravity, their swimming speeds changed differently according to the direction of swimming. When a mouse subjected to acupuncture for three days is exposed to microgravity, its water metabolism and excretory function are enhanced. A mouse treated with Chinese medicine reacts in the similar way. The change due to microgravity in the amount of acetylcholine in the hypothalamus is found characteristically time dependent. Mice infected with lethal herpes viruses just after exposure to microgravity die at a rate in proportion to the number of exposures and to the amount of viruses given. The migration speed of chemical stripes in case of a gel-base BZ (Belousov-Zhabotinsky) reaction under microgravity is equal to that on the ground. The trigger wave migration speed in case of a water solution-base BZ reaction under microgravity is reduced to approximately 80% of the speed on the ground. 12 refs., 31 figs., 3 tabs.

Agglomeration of Ni-nanoparticles in the gas phase under gravity and microgravity conditions

International Nuclear Information System (INIS)

Lösch, S; Günther, B H; Iles, G N; Schmitz, B

2011-01-01

The agglomeration of metallic nanoparticles can be performed using the well-known inert gas condensation process. Unfortunately, thermal effects such as convection are created by the heating source and as a result the turbulent aerosol avoids ideal conditions. In addition, the sedimentation of large particles and/or agglomerates influences the self-assembly of particles. These negative effects can be eliminated by using microgravity conditions. Here we present the results of the agglomeration of nanoscale Ni-particles under gravity and microgravity conditions, the latter provided by adapted microgravity platforms namely the European sounding rocket MAXUS 8 and the European Parabolic Flight aircraft, Airbus A300 Zero-G.

Simulated conditions of microgravity suppress progesterone production by luteal cells of the pregnant rat

Science.gov (United States)

Bhat, G. K.; Yang, H.; Sridaran, R.

2001-01-01

The purpose of this study was to assess whether simulated conditions of microgravity induce changes in the production of progesterone by luteal cells of the pregnant rat ovary using an in vitro model system. The microgravity environment was simulated using either a high aspect ratio vessel (HARV) bioreactor with free fall or a clinostat without free fall of cells. A mixed population of luteal cells isolated from the corpora lutea of day 8 pregnant rats was attached to cytodex microcarrier beads (cytodex 3). These anchorage dependent cells were placed in equal numbers in the HARV or a spinner flask control vessel in culture conditions. It was found that HARV significantly reduced the daily production of progesterone from day 1 through day 8 compared to controls. Scanning electron microscopy showed that cells attached to the microcarrier beads throughout the duration of the experiment in both types of culture vessels. Cells cultured in chamber slide flasks and placed in a clinostat yielded similar results when compared to those in the HARV. Also, when they were stained by Oil Red-O for lipid droplets, the clinostat flasks showed a larger number of stained cells compared to control flasks at 48 h. Further, the relative amount of Oil Red-O staining per milligram of protein was found to be higher in the clinostat than in the control cells at 48 h. It is speculated that the increase in the level of lipid content in cells subjected to simulated conditions of microgravity may be due to a disruption in cholesterol transport and/or lesions in the steroidogenic pathway leading to a fall in the synthesis of progesterone. Additionally, the fall in progesterone in simulated conditions of microgravity could be due to apoptosis of luteal cells.

A Systems Biology Analysis Unfolds the Molecular Pathways and Networks of Two Proteobacteria in Spaceflight and Simulated Microgravity Conditions.

Science.gov (United States)

Roy, Raktim; Shilpa, P Phani; Bagh, Sangram

2016-09-01

Bacteria are important organisms for space missions due to their increased pathogenesis in microgravity that poses risks to the health of astronauts and for projected synthetic biology applications at the space station. We understand little about the effect, at the molecular systems level, of microgravity on bacteria, despite their significant incidence. In this study, we proposed a systems biology pipeline and performed an analysis on published gene expression data sets from multiple seminal studies on Pseudomonas aeruginosa and Salmonella enterica serovar Typhimurium under spaceflight and simulated microgravity conditions. By applying gene set enrichment analysis on the global gene expression data, we directly identified a large number of new, statistically significant cellular and metabolic pathways involved in response to microgravity. Alteration of metabolic pathways in microgravity has rarely been reported before, whereas in this analysis metabolic pathways are prevalent. Several of those pathways were found to be common across studies and species, indicating a common cellular response in microgravity. We clustered genes based on their expression patterns using consensus non-negative matrix factorization. The genes from different mathematically stable clusters showed protein-protein association networks with distinct biological functions, suggesting the plausible functional or regulatory network motifs in response to microgravity. The newly identified pathways and networks showed connection with increased survival of pathogens within macrophages, virulence, and antibiotic resistance in microgravity. Our work establishes a systems biology pipeline and provides an integrated insight into the effect of microgravity at the molecular systems level. Systems biology-Microgravity-Pathways and networks-Bacteria. Astrobiology 16, 677-689.

A Zero-Gravity Cup for Drinking Beverages in Microgravity

Science.gov (United States)

Pettit, Donald R.; Weislogel, Mark; Concus, Paul; Finn, Robert

2011-01-01

To date, the method for astronauts to drink liquids in microgravity or weightless environments is to suck the liquid from a bag or pouch through a straw. A new beverage cup works in microgravity and allows astronauts to drink liquids from a cup in a manner consistent with that on Earth. The cup is capable of holding beverages with an angled channel running along the wall from the bottom to the lip. In microgravity, a beverage is placed into the cup using the galley dispenser. The angled channel acts as an open passage that contains only two sides where capillary forces move the liquid along the channel until it reaches the top lip where the forces reach an equilibrium and the flow stops. When one sips the liquid at the lip of the channel, the capillary force equilibrium is upset and more liquid flows to the lip from the reservoir at the bottom to re-establish the equilibrium. This sipping process can continue until the total liquid contents of the cup is consumed, leaving only a few residual drops about the same quantity as in a ceramic cup when it is drunk dry on Earth.

Shape Evolution of Detached Bridgman Crystals Grown in Microgravity

Science.gov (United States)

Volz, M. P.; Mazuruk, K.

2015-01-01

A theory describing the shape evolution of detached Bridgman crystals in microgravity has been developed. A starting crystal of initial radius r0 will evolve to one of the following states: Stable detached gap; Attachment to the crucible wall; Meniscus collapse. Only crystals where alpha plus omega is great than 180 degrees will achieve stable detached growth in microgravity. Results of the crystal shape evolution theory are consistent with predictions of the dynamic stability of crystallization (Tatarchenko, Shaped Crystal Growth, Kluwer, 1993). Tests of transient crystal evolution are planned for ICESAGE, a series of Ge and GeSi crystal growth experiments planned to be conducted on the International Space Station (ISS).

ISS Microgravity Research Payload Training Methodology

Science.gov (United States)

Schlagheck, Ronald; Geveden, Rex (Technical Monitor)

2001-01-01

The NASA Microgravity Research Discipline has multiple categories of science payloads that are being planned and currently under development to operate on various ISS on-orbit increments. The current program includes six subdisciplines; Materials Science, Fluids Physics, Combustion Science, Fundamental Physics, Cellular Biology and Macromolecular Biotechnology. All of these experiment payloads will require the astronaut various degrees of crew interaction and science observation. With the current programs planning to build various facility class science racks, the crew will need to be trained on basic core operations as well as science background. In addition, many disciplines will use the Express Rack and the Microgravity Science Glovebox (MSG) to utilize the accommodations provided by these facilities for smaller and less complex type hardware. The Microgravity disciplines will be responsible to have a training program designed to maximize the experiment and hardware throughput as well as being prepared for various contingencies both with anomalies as well as unexpected experiment observations. The crewmembers will need various levels of training from simple tasks as power on and activate to extensive training on hardware mode change out to observing the cell growth of various types of tissue cultures. Sample replacement will be required for furnaces and combustion type modules. The Fundamental Physics program will need crew EVA support to provide module change out of experiment. Training will take place various research centers and hardware development locations. It is expected that onboard training through various methods and video/digital technology as well as limited telecommunication interaction. Since hardware will be designed to operate from a few weeks to multiple research increments, flexibility must be planned in the training approach and procedure skills to optimize the output as well as the equipment maintainability. Early increment lessons learned

How to Demonstrate Microgravity in your Classroom

Science.gov (United States)

DeLombard, Richard; Hall, Nancy Rabel

2013-01-01

Learn why zero gravity is a misnomer and learn how to demonstrate microgravity to students and the general public. In this session, a short theory segment will explain and reinforce these concepts so that you may explain to others. Session participants will also see simple equipment that demonstrates microgravity during the session and can just as well be done in the classroom or museum exhibit hall. The hands-on demonstration devices range from a leaky water bottle to an electronic drop tower with an on-board camera. The session will also include demonstration techniques for Physics, Forces & Motion, and orbits. This material is useful for middle school forces and motions instruction, high school physics instruction, public demonstrations at conferences & school open houses, travelling museum exhibits, fixed museum exhibits, and independent student projects or experiments. These activities also connect the terrestrial demonstration with planetary & moon motion, comet trajectory, and more.

Microgravity, Stem Cells, and Embryonic Development: Challenges and Opportunities for 3D Tissue Generation

International Nuclear Information System (INIS)

Andreazzoli, Massimiliano; Angeloni, Debora; Broccoli, Vania; Demontis, Gian C.

2017-01-01

Space is a challenging environment for the human body, due to the combined effects of reduced gravity (microgravity) and cosmic radiation. Known effects of microgravity range from the blood redistribution that affects the cardiovascular system and the eye to muscle wasting, bone loss, anemia, and immune depression. About cosmic radiation, the shielding provided by the spaceship hull is far less efficient than that afforded at ground level by the combined effects of the Earth atmosphere and magnetic field. The eye and its nervous layer (the retina) are affected by both microgravity and heavy ions exposure. Considering the importance of sight for long-term manned flights, visual research aimed at devising measures to protect the eye from environmental conditions of the outer space represents a special challenge to meet. In this review we focus on the impact of microgravity on embryonic development, discussing the roles of mechanical forces in the context of the neutral buoyancy the embryo experiences in the womb. At variance with its adverse effects on the adult human body, simulated microgravity may provide a unique tool for understanding the biomechanical events involved in the development and assembly in vitro of three-dimensional (3D) ocular tissues. Prospective benefits are the development of novel safety measures to protect the human eye from cosmic radiation in microgravity during long-term manned spaceflights in the outer space, as well as the generation of human 3D-retinas with its supporting structures to develop innovative and effective therapeutic options for degenerative eye diseases.

Microgravity, Stem Cells, and Embryonic Development: Challenges and Opportunities for 3D Tissue Generation

Energy Technology Data Exchange (ETDEWEB)

Andreazzoli, Massimiliano [Department of Biology, University of Pisa, Pisa (Italy); Angeloni, Debora [Institute of Life Sciences, Scuola Superiore Sant' Anna, Pisa (Italy); Broccoli, Vania [National Research Council, Institute of Neuroscience, Milan (Italy); Stem Cells and Neurogenesis Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan (Italy); Demontis, Gian C., E-mail: giancarlo.demontis@farm.unipi.it [Department of Pharmacy and Centro D' Ateneo “E. Piaggio”, University of Pisa, Pisa (Italy)

2017-04-25

Space is a challenging environment for the human body, due to the combined effects of reduced gravity (microgravity) and cosmic radiation. Known effects of microgravity range from the blood redistribution that affects the cardiovascular system and the eye to muscle wasting, bone loss, anemia, and immune depression. About cosmic radiation, the shielding provided by the spaceship hull is far less efficient than that afforded at ground level by the combined effects of the Earth atmosphere and magnetic field. The eye and its nervous layer (the retina) are affected by both microgravity and heavy ions exposure. Considering the importance of sight for long-term manned flights, visual research aimed at devising measures to protect the eye from environmental conditions of the outer space represents a special challenge to meet. In this review we focus on the impact of microgravity on embryonic development, discussing the roles of mechanical forces in the context of the neutral buoyancy the embryo experiences in the womb. At variance with its adverse effects on the adult human body, simulated microgravity may provide a unique tool for understanding the biomechanical events involved in the development and assembly in vitro of three-dimensional (3D) ocular tissues. Prospective benefits are the development of novel safety measures to protect the human eye from cosmic radiation in microgravity during long-term manned spaceflights in the outer space, as well as the generation of human 3D-retinas with its supporting structures to develop innovative and effective therapeutic options for degenerative eye diseases.

Multiphase flow and phase change in microgravity: Fundamental research and strategic research for exploration of space

Science.gov (United States)

Singh, Bhim S.

2003-01-01

NASA is preparing to undertake science-driven exploration missions. The NASA Exploration Team's vision is a cascade of stepping stones. The stepping-stone will build the technical capabilities needed for each step with multi-use technologies and capabilities. An Agency-wide technology investment and development program is necessary to implement the vision. The NASA Exploration Team has identified a number of areas where significant advances are needed to overcome all engineering and medical barriers to the expansion of human space exploration beyond low-Earth orbit. Closed-loop life support systems and advanced propulsion and power technologies are among the areas requiring significant advances from the current state-of-the-art. Studies conducted by the National Academy of Science's National Research Council and Workshops organized by NASA have shown that multiphase flow and phase change play a crucial role in many of these advanced technology concepts. Lack of understanding of multiphase flow, phase change, and interfacial phenomena in the microgravity environment has been a major hurdle. An understanding of multiphase flow and phase change in microgravity is, therefore, critical to advancing many technologies needed. Recognizing this, the Office of Biological and Physical Research (OBPR) has initiated a strategic research thrust to augment the ongoing fundamental research in fluid physics and transport phenomena discipline with research especially aimed at understanding key multiphase flow related issues in propulsion, power, thermal control, and closed-loop advanced life support systems. A plan for integrated theoretical and experimental research that has the highest probability of providing data, predictive tools, and models needed by the systems developers to incorporate highly promising multiphase-based technologies is currently in preparation. This plan is being developed with inputs from scientific community, NASA mission planners and industry personnel

Zero-Energy Ultrafast Water Nanofiltration System in Microgravity

Data.gov (United States)

National Aeronautics and Space Administration — The goal of this program is to develop a water nanofiltration system that functions in microgravity for use during a long-duration human space exploration. The...

Rheological Properties of Quasi-2D Fluids in Microgravity

Science.gov (United States)

Stannarius, Ralf; Trittel, Torsten; Eremin, Alexey; Harth, Kirsten; Clark, Noel; Maclennan, Joseph; Glaser, Matthew; Park, Cheol; Hall, Nancy; Tin, Padetha

2015-01-01

In recent years, research on complex fluids and fluids in restricted geometries has attracted much attention in the scientific community. This can be attributed not only to the development of novel materials based on complex fluids but also to a variety of important physical phenomena which have barely been explored. One example is the behavior of membranes and thin fluid films, which can be described by two-dimensional (2D) rheology behavior that is quite different from 3D fluids. In this study, we have investigated the rheological properties of freely suspended films of a thermotropic liquid crystal in microgravity experiments. This model system mimics isotropic and anisotropic quasi 2D fluids [46]. We use inkjet printing technology to dispense small droplets (inclusions) onto the film surface. The motion of these inclusions provides information on the rheological properties of the films and allows the study of a variety of flow instabilities. Flat films have been investigated on a sub-orbital rocket flight and curved films (bubbles) have been studied in the ISS project OASIS. Microgravity is essential when the films are curved in order to avoid sedimentation. The experiments yield the mobility of the droplets in the films as well as the mutual mobility of pairs of particles. Experimental results will be presented for 2D-isotropic (smectic-A) and 2D-nematic (smectic-C) phases.

Microgravity Flammability Experiments for Spacecraft Fire Safety

DEFF Research Database (Denmark)

Legros, Guillaume; Minster, Olivier; Tóth, Balazs

2012-01-01

As fire behaviour in manned spacecraft still remains poorly understood, an international topical team has been created to design a validation experiment that has an unprecedented large scale for a microgravity flammability experiment. While the validation experiment is being designed for a re-sup...

Cell-wall architecture and lignin composition of wheat developed in a microgravity environment

Science.gov (United States)

Levine, L. H.; Heyenga, A. G.; Levine, H. G.; Choi, J.; Davin, L. B.; Krikorian, A. D.; Lewis, N. G.; Sager, J. C. (Principal Investigator)

2001-01-01

The microgravity environment encountered during space-flight has long been considered to affect plant growth and developmental processes, including cell wall biopolymer composition and content. As a prelude to studying how microgravity is perceived - and acted upon - by plants, it was first instructive to investigate what gross effects on plant growth and development occurred in microgravity. Thus, wheat seedlings were exposed to microgravity on board the space shuttle Discovery (STS-51) for a 10 day duration, and these specimens were compared with their counterparts grown on Earth under the same conditions (e.g. controls). First, the primary roots of the wheat that developed under both microgravity and 1 g on Earth were examined to assess the role of gravity on cellulose microfibril (CMF) organization and secondary wall thickening patterns. Using a quick freeze/deep etch technique, this revealed that the cell wall CMFs of the space-grown wheat maintained the same organization as their 1 g-grown counterparts. That is, in all instances, CMFs were randomly interwoven with each other in the outermost layers (farthest removed from the plasma membrane), and parallel to each other within the individual strata immediately adjacent to the plasma membranes. The CMF angle in the innermost stratum relative to the immediately adjacent stratum was ca 80 degrees in both the space and Earth-grown plants. Second, all plants grown in microgravity had roots that grew downwards into the agar; they did not display "wandering" and upward growth as previously reported by others. Third, the space-grown wheat also developed normal protoxylem and metaxylem vessel elements with secondary thickening patterns ranging from spiral to regular pit to reticulate thickenings. Fourthly, both the space- and Earth-grown plants were essentially of the same size and height, and their lignin analyses revealed no substantial differences in their amounts and composition regardless of the gravitational

Fundamental Research Applied To Enable Hardware Performance in Microgravity

Science.gov (United States)

Sheredy, William A.

2005-01-01

NASA sponsors microgravity research to generate knowledge in physical sciences. In some cases, that knowledge must be applied to enable future research. This article describes one such example. The Dust and Aerosol measurement Feasibility Test (DAFT) is a risk-mitigation experiment developed at the NASA Glenn Research Center by NASA and ZIN Technologies, Inc., in support of the Smoke Aerosol Measurement Experiment (SAME). SAME is an investigation that is being designed for operation in the Microgravity Science Glovebox aboard the International Space Station (ISS). The purpose of DAFT is to evaluate the performance of P-Trak (TSI Incorporated, Shoreview, MN)--a commercially available condensation nuclei counter and a key SAME diagnostic- -in long-duration microgravity because of concerns about its ability to operate properly in that environment. If its microgravity performance is proven, this device will advance the state of the art in particle measurement capabilities for space vehicles and facilities, such as aboard the ISS. The P-Trak, a hand-held instrument, can count individual particles as small as 20 nm in diameter in an aerosol stream. Particles are drawn into the device by a built-in suction pump. Upon entering the instrument, these particles pass through a saturator tube where they mix with an alcohol vapor (see the following figure). This mixture then flows through a cooled condenser tube where some of the alcohol condenses onto the sample particles, and the droplets grow in a controlled fashion until they are large enough to be counted. These larger droplets pass through an internal nozzle and past a focused laser beam, producing flashes of light that are sensed by a photodetector and then counted to determine particle number concentration. The operation of the instrument depends on the proper internal flow and recycling of isopropyl alcohol in both the vapor and liquid phases.

Characteristics of transitional and turbulent jet diffusion flames in microgravity

Science.gov (United States)

Bahadori, Yousef M.; Small, James F., Jr.; Hegde, Uday G.; Zhou, Liming; Stocker, Dennis P.

1995-01-01

This paper presents the ground-based results obtained to date in preparation of a proposed space experiment to study the role of large-scale structures in microgravity transitional and turbulent gas-jet diffusion flames by investigating the dynamics of vortex/flame interactions and their influence on flame characteristics. The overall objective is to gain an understanding of the fundamental characteristics of transitional and turbulent gas-jet diffusion flames. Understanding of the role of large-scale structures on the characteristics of microgravity transitional and turbulent flames will ultimately lead to improved understanding of normal-gravity turbulent combustion.

Microgravity-associated Changes in Cellular Signal Processing

Science.gov (United States)

Mednieks, M. I.; Hand, Arthur

It has been an ongoing interest in the NASA Life Sciences Division to determine the physiologic effects of space travel and to devise countermeasures to those effects that can be detrimental to humans. In addition to study of animals flown on the US STS-131, 133 and 135 shuttle missions, participating in the Russian COSMOS and BION-M1 missions has provided important opportunities to study the effects of microgravity on hormonal regulation of cell and tissue responses and on a defined molecular basis. A mouse model was employed to study the effects of space flight on regulation of protein secretion in oral fluid. Using morphologic, and molecular methods it was determined that the expression of a number of proteins is altered after space flight when compared to that of controls. Shown by microarray analyses, some salivary gland genes are down regulated, others up-regulated, while the majority are unaffected. Electron microscopic examination of salivary glands showed no overall tissue damage, but specific morphologic effects were seen that are consistent with an increase in apoptosis and altered duct cell function. Immuno-cytochemical and biochemical methods were used to identify the specific proteins. Initial studies indicate that some of the effects appear transient and could be an adjustment or homeostatic response to microgravity conditions. Further studies will determine if a pharmacologic means can serve as a countermeasure to physiologic changes in humans in catecholamine hormone regulated responses due to travel in space. Support: CT Space Grant College Consortium, School of Dental Medicine Alumni Research Fellowship and the NASA Award Number, NNX09AP13G,

Identification and characterization of PhoP regulon members in Yersinia pestis biovar Microtus

Directory of Open Access Journals (Sweden)

Du Zongmin

2008-03-01

Full Text Available Abstract Background The transcription regulator PhoP has been shown to be important for Y. pestis survival in macrophages and under various in vitro stresses. However, the mechanism by which PhoP promotes bacterial intracellular survival is not fully understood. Our previous microarray analysis suggested that PhoP governed a wide set of cellular pathways in Y. pestis. A series of biochemical experiments were done herein to study members of the PhoP regulon of Y. pestis biovar Microtus. Results By using gel mobility shift assay and quantitative RT-PCR, a total of 30 putative transcription units were characterized as direct PhoP targets. The primer extension assay was further used to determine the transcription start sites of 18 PhoP-dependent promoters and to localize the -10 and -35 elements. The DNase I footprinting was used to identify the PhoP-binding sites within 17 PhoP-dependent promoters, enabling the identification of PhoP box and matrix that both represented the conserved signals for PhoP recognition in Y. pestis. Data presented here providing a good basis for modeling PhoP-promoter DNA interactions that is crucial to the PhoP-mediated transcriptional regulation. Conclusion The proven direct PhoP targets include nine genes encoding regulators and 21 genes or operons with functions of detoxification, protection against DNA damages, resistance to antimicrobial peptides, and adaptation to magnesium limitation. We can presume that PhoP is a global regulator that controls a complex regulatory cascade by a mechanism of not only directly controlling the expression of specific genes, but also indirectly regulating various cellular pathways by acting on a set of dedicated regulators. These results help us gain insights into the PhoP-dependent mechanisms by which Y. pestis survives the antibacterial strategies employed by host macrophages.

Computational Modeling of Cephalad Fluid Shift for Application to Microgravity-Induced Visual Impairment

Science.gov (United States)

Nelson, Emily S.; Best, Lauren M.; Myers, Jerry G.; Mulugeta, Lealem

2013-01-01

An improved understanding of spaceflight-induced ocular pathology, including the loss of visual acuity, globe flattening, optic disk edema and distension of the optic nerve and optic nerve sheath, is of keen interest to space medicine. Cephalad fluid shift causes a profoundly altered distribution of fluid within the compartments of the head and body, and may indirectly generate phenomena that are biomechanically relevant to visual function, such as choroidal engorgement, compromised drainage of blood and cerebrospinal fluid (CSF), and altered translaminar pressure gradient posterior to the eye. The experimental body of evidence with respect to the consequences of fluid shift has not yet been able to provide a definitive picture of the sequence of events. On earth, elevated intracranial pressure (ICP) is associated with idiopathic intracranial hypertension (IIH), which can produce ocular pathologies that look similar to those seen in some astronauts returning from long-duration flight. However, the clinically observable features of the Visual Impairment and Intracranial Pressure (VIIP) syndrome in space and IIH on earth are not entirely consistent. Moreover, there are at present no experimental measurements of ICP in microgravity. By its very nature, physiological measurements in spaceflight are sparse, and the space environment does not lend itself to well-controlled experiments. In the absence of such data, numerical modeling can play a role in the investigation of biomechanical causal pathways that are suspected of involvement in VIIP. In this work, we describe the conceptual framework for modeling the altered compartmental fluid distribution that represents an equilibrium fluid distribution resulting from the loss of hydrostatic pressure gradient.

Experimental study of two-phase flow in a proton exchange membrane fuel cell in short-term microgravity condition

International Nuclear Information System (INIS)

Guo, Hang; Liu, Xuan; Zhao, Jian Fu; Ye, Fang; Ma, Chong Fang

2014-01-01

Highlights: • Two-phase flow in PEMFC cathode channels is observed in different gravity environments. • The PEMFC shows different operating behavior in normal and microgravity conditions. • Water tends can be removed in microgravity conditions at high water production regime. • Liquid aggregation occurs in microgravity conditions at low water production regime. • Effect of gravity on performance and two-phase flow at two operating regimes is studied. - Abstract: Water management is important for improving the performance and stability of proton exchange membrane fuel cells (PEMFCs) for space applications. An in situ visual observation was conducted on the gas–liquid two-phase flow in the cathode channels of a PEMFC in short-term microgravity condition. The microgravity environment was supplied by a drop tower. A single serpentine flow channel with a depth of 2 mm and a width of 2 mm was applied as the cathode flow field. A membrane electrode assembly comprising of a Nafion 112 membrane sandwiched between gas diffusion layers was used. The anode and cathode were loaded with 1 mg cm −2 platinum. The PEMFC shows a distinct operating behavior in microgravity because of the effect of gravity on the two-phase flow. At a high water production regime, cell performance is enhanced by 4.6% and the accumulated liquid water in the flow channel tends can be removed in microgravity conditions to alleviate flooding. At a low water production regime, cell performance deteriorates by 6.6% and liquid aggregation occurs in the flow channel because of the coalescence of dispersed water droplets in microgravity conditions, thus squeezing the flow channel. The operating behavior of PEMFC in microgravity conditions is different from that in normal gravity conditions. Further studies are needed on PEMFC operating characteristics and liquid management for space applications

Development of an Autonomous, Dual Chamber Bioreactor for the Growth of 3-Dimensional Epithelial-Stromal Tissues in Microgravity

Science.gov (United States)

Patel, Zarana S.; Wettergreen, Matthew A.; Huff, Janice L.

2014-01-01

We are developing a novel, autonomous bioreactor that can provide for the growth and maintenance in microgravity of 3-D organotypic epithelial-stromal cultures that require an air-liquid interface. These complex 3-D tissue models accurately represent the morphological features, differentiation markers, and growth characteristics observed in normal human epithelial tissues, including the skin, esophagus, lung, breast, pancreas, and colon. However, because of their precise and complex culture requirements, including that of an air-liquid interface, these 3-D models have yet to be utilized for life sciences research aboard the International Space Station. The development of a bioreactor for these cultures will provide the capability to perform biological research on the ISS using these realistic, tissue-like human epithelial-stromal cell models and will contribute significantly to advances in fundamental space biology research on questions regarding microgravity effects on normal tissue development, aging, cancer, and other disease processes. It will also allow for the study of how combined stressors, such as microgravity with radiation and nutritional deficiencies, affect multiple biological processes and will provide a platform for conducting countermeasure investigations on the ISS without the use of animal models. The technology will be autonomous and consist of a cell culture chamber that provides for air-liquid, liquid-liquid, and liquid-air exchanges within the chambers while maintaining the growth and development of the biological samples. The bioreactor will support multiple tissue types and its modular design will provide for incorporation of add-on capabilities such as microfluidics drug delivery, media sampling, and in situ biomarker analysis. Preliminary flight testing of the hardware will be conducted on a parabolic platform through NASA's Flight Opportunities Program.

The current state of bone loss research: data from spaceflight and microgravity simulators.

Science.gov (United States)

Nagaraja, Mamta Patel; Risin, Diana

2013-05-01

Bone loss is a well documented phenomenon occurring in humans both in short- and in long-term spaceflights. This phenomenon can be also reproduced on the ground in human and animals and also modeled in cell-based analogs. Since space flights are infrequent and expensive to study the biomedical effects of microgravity on the human body, much of the known pathology of bone loss comes from experimental studies. The most commonly used in vitro simulators of microgravity are clinostats while in vivo simulators include the bed rest studies in humans and hindlimb unloading experiments in animals. Despite the numerous reports that have documented bone loss in wide ranges in multiple crew members, the pathology remains a key concern and development of effective countermeasures is still a major task. Thus far, the offered modalities have not shown much success in preventing or alleviating bone loss in astronauts and cosmonauts. The objective of this review is to capture the most recent research on bone loss from spaceflights, bed rest and hindlimb unloading, and in vitro studies utilizing cellular models in clinostats. Additionally, this review offers projections on where the research has to focus to ensure the most rapid development of effective countermeasures. Copyright © 2012 Wiley Periodicals, Inc.

Growing tissues in real and simulated microgravity: new methods for tissue engineering.

Science.gov (United States)

Grimm, Daniela; Wehland, Markus; Pietsch, Jessica; Aleshcheva, Ganna; Wise, Petra; van Loon, Jack; Ulbrich, Claudia; Magnusson, Nils E; Infanger, Manfred; Bauer, Johann

2014-12-01

Tissue engineering in simulated (s-) and real microgravity (r-μg) is currently a topic in Space medicine contributing to biomedical sciences and their applications on Earth. The principal aim of this review is to highlight the advances and accomplishments in the field of tissue engineering that could be achieved by culturing cells in Space or by devices created to simulate microgravity on Earth. Understanding the biology of three-dimensional (3D) multicellular structures is very important for a more complete appreciation of in vivo tissue function and advancing in vitro tissue engineering efforts. Various cells exposed to r-μg in Space or to s-μg created by a random positioning machine, a 2D-clinostat, or a rotating wall vessel bioreactor grew in the form of 3D tissues. Hence, these methods represent a new strategy for tissue engineering of a variety of tissues, such as regenerated cartilage, artificial vessel constructs, and other organ tissues as well as multicellular cancer spheroids. These aggregates are used to study molecular mechanisms involved in angiogenesis, cancer development, and biology and for pharmacological testing of, for example, chemotherapeutic drugs or inhibitors of neoangiogenesis. Moreover, they are useful for studying multicellular responses in toxicology and radiation biology, or for performing coculture experiments. The future will show whether these tissue-engineered constructs can be used for medical transplantations. Unveiling the mechanisms of microgravity-dependent molecular and cellular changes is an up-to-date requirement for improving Space medicine and developing new treatment strategies that can be translated to in vivo models while reducing the use of laboratory animals.

Problems in Microgravity Fluid Mechanics: G-Jitter Convection

Science.gov (United States)

Homsy, G. M.

2005-01-01

This is the final report on our NASA grant, Problems in Microgravity Fluid Mechanics NAG3-2513: 12/14/2000 - 11/30/2003, extended through 11/30/2004. This grant was made to Stanford University and then transferred to the University of California at Santa Barbara when the PI relocated there in January 2001. Our main activity has been to conduct both experimental and theoretical studies of instabilities in fluids that are relevant to the microgravity environment, i.e. those that do not involve the action of buoyancy due to a steady gravitational field. Full details of the work accomplished under this grant are given below. Our work has focused on: (i) Theoretical and computational studies of the effect of g-jitter on instabilities of convective states where the convection is driven by forces other than buoyancy (ii) Experimental studies of instabilities during displacements of miscible fluid pairs in tubes, with a focus on the degree to which these mimic those found in immiscible fluids. (iii) Theoretical and experimental studies of the effect of time dependent electrohydrodynamic forces on chaotic advection in drops immersed in a second dielectric liquid. Our objectives are to acquire insight and understanding into microgravity fluid mechanics problems that bear on either fundamental issues or applications in fluid physics. We are interested in the response of fluids to either a fluctuating acceleration environment or to forces other than gravity that cause fluid mixing and convection. We have been active in several general areas.

Germination and elongation of flax in microgravity

Science.gov (United States)

Levine, Howard G.; Anderson, Ken; Boody, April; Cox, Dave; Kuznetsov, Oleg A.; Hasenstein, Karl H.

2003-05-01

This experiment was conducted as part of a risk mitigation payload aboard the Space Shuttle Atlantis on STS-101. The objectives were to test a newly developed water delivery system, and to determine the optimal combination of water volume and substrate for the imbibition and germination of flax ( Linum usitatissimum) seeds in space. Two different combinations of germination paper were tested for their ability to absorb, distribute, and retain water in microgravity. A single layer of thick germination paper was compared with one layer of thin germination paper under a layer of thick paper. Paper strips were cut to fit snugly into seed cassettes, and seeds were glued to them with the micropyle ends pointing outward. Water was delivered in small increments that traveled through the paper via capillary action. Three water delivery volumes were tested, with the largest (480 μL) outperforming the 400 μL, and 320 μL volumes for percent germination (90.6%) and root growth (mean = 4.1 mm) during the 34-hour spaceflight experiment. The ground control experiment yielded similar results, but with lower rates of germination (84.4%) and shorter root lengths (mean = 2.8 mm). It is not clear if the roots emerged more quickly in microgravity and/or grew faster than the ground controls. The single layer of thick germination paper generally exhibited better overall growth than the two layered option. Significant seed position effects were observed in both the flight and ground control experiments. Overall, the design of the water delivery system, seed cassettes and the germination paper strip concept was validated as an effective method for promoting seed germination and root growth under microgravity conditions.

Spaceflight and Simulated Microgravity Increases Virulence of the Known Bacterial Pathogen S. Marcescens

Science.gov (United States)

Clemens-Grisham, Rachel Andrea; Bhattacharya, Sharmila; Wade, William

2016-01-01

After spaceflight, the number of immune cells is reduced in humans. In other research models, including Drosophila, not only is there a reduction in the number of plasmatocytes, but expression of immune-related genes is also changed after spaceflight. These observations suggest that the immune system is compromised after exposure to microgravity. It has also been reported that there is a change in virulence of some bacterial pathogens after spaceflight. We recently observed that samples of gram-negative S. marcescens retrieved from spaceflight is more virulent than ground controls, as determined by reduced survival and increased bacterial growth in the host. We were able to repeat this finding of increased virulence after exposure to simulated microgravity using the rotating wall vessel, a ground based analog to microgravity. With the ground and spaceflight samples, we looked at involvement of the Toll and Imd pathways in the Drosophila host in fighting infection by ground and spaceflight samples. We observed that Imd-pathway mutants were more susceptible to infection by the ground bacterial samples, which aligns with the known role of this pathway in fighting infections by gram-negative bacteria. When the Imd-pathway mutants were infected with the spaceflight sample, however, they exhibited the same susceptibility as seen with the ground control bacteria. Interestingly, all mutant flies show the same susceptibility to the spaceflight bacterial sample as do wild type flies. This suggests that neither humoral immunity pathway is effectively able to counter the increased pathogenicity of the space-flown S. marcescens bacteria.

Microstructural anomalies in a W-Ni alloy liquid phase sintered under microgravity conditions

International Nuclear Information System (INIS)

Liu, Y.; Iacocca, R.G.; Johnson, J.L.; German, R.M.; Kohara, Shiro

1995-01-01

The gravitational role in liquid phase sintering (LPS) is a problem of great interest in both materials science and engineering practice. Gravity-induced microstructural gradients in grain size, grain shape, and solid volume fraction have been well documented in liquid phase sintered tungsten heavy alloys and have been analyzed by a number of theoretical models. However, gravity may have many unknown effects on LPS, which can only be revealed by experiments conducted under microgravity conditions

Effect Of Low External Flow On Flame Spreading Over ETFE Insulated Wire Under Microgravity

Science.gov (United States)

Nishizawa, Katsuhiro; Fujita, Osamu; Ito, Kenichi; Kikuchi, Masao; Olson, Sandra L.; Kashiwagi, Takashi

2003-01-01

Fire safety is one of the most important issues for manned space missions. A likely cause of fires in spacecraft is wire insulation combustion in electrical system. Regarding the wire insulation combustion it important to know the effect of low external flow on the combustion because of the presence of ventilation flow in spacecraft. Although, there are many researches on flame spreading over solid material at low external flows under microgravity, research dealing with wire insulation is very limited. An example of wire insulation combustion in microgravity is the Space Shuttle experiments carried out by Greenberg et al. However, the number of experiments was very limited. Therefore, the effect of low flow velocity is still not clear. The authors have reported results on flame spreading over ETFE (ethylene - tetrafluoroetylene) insulated wire in a quiescent atmosphere in microgravity by 10 seconds drop tower. The authors also performed experiments of polyethylene insulated nichrom wire combustion in low flow velocity under microgravity. The results suggested that flame spread rate had maximum value in low flow velocity condition. Another interesting issue is the effect of dilution gas, especially CO2, which is used for fire extinguisher in ISS. There are some researches working on dilution gas effect on flame spreading over solid material in quiescent atmosphere in microgravity. However the research with low external flow is limited and, of course, the research discussing a relation of the appearance of maximum wire flammability in low flow velocity region with different dilution gas cannot be found yet. The present paper, therefore, investigates the effect of opposed flow with different dilution gas on flame spreading over ETFE insulated wire and change in the presence of the maximum flammability depending on the dilution gas type is discussed within the limit of microgravity time given by ground-based facility.

Analysis of Statoliths Displacement in Chara Rhizoids for Validating the Microgravity-Simulation Quality of Clinorotation Modes

Science.gov (United States)

Krause, Lars; Braun, Markus; Hauslage, Jens; Hemmersbach, Ruth

2018-05-01

In single-celled rhizoids of the green algae Chara, positively gravitropic growth is governed by statoliths kept in a dynamically stable position 10-25 μ m above the cell tip by a complex interaction of gravity and actomyosin forces. Any deviation of the tube-like cells from the tip-downward orientation causes statoliths to sediment onto the gravisensitive subapical cell flank which initiates a gravitropic curvature response. Microgravity experiments have shown that abolishing the net tip-directed gravity force results in an actomyosin-mediated axial displacement of statoliths away from the cell tip. The present study was performed to critically assess the quality of microgravity simulation provided by different operational modes of a Random Positioning Machine (RPM) running with one axis (2D mode) or two axes (3D mode) and different rotational speeds (2D), speed ranges and directions (3D). The effects of 2D and 3D rotation were compared with data from experiments in real microgravity conditions (MAXUS sounding rocket missions). Rotational speeds in the range of 60-85 rpm in 2D and 3D modes resulted in a similar kinetics of statolith displacement as compared to real microgravity data, while slower clinorotation (2-11 rpm) caused a reduced axial displacement and a more dispersed arrangement of statoliths closer to the cell tip. Increasing the complexity of rotation by adding a second rotation axis in case of 3D clinorotation did not increase the quality of microgravity simulation, however, increased side effects such as the level of vibrations resulting in a more dispersed arrangement of statoliths. In conclusion, fast 2D clinorotation provides the most appropriate microgravity simulation for investigating the graviperception mechanism in Chara rhizoids, whereas slower clinorotation speeds and rotating samples around two axes do not improve the quality of microgravity simulation.

Microgravity Flight - Accommodating Non-Human Primates

Science.gov (United States)

Dalton, Bonnie P.; Searby, Nancy; Ostrach, Louis

1994-01-01

Spacelab Life Sciences-3 (SLS-3) was scheduled to be the first United States man-tended microgravity flight containing Rhesus monkeys. The goal of this flight as in the five untended Russian COSMOS Bion flights and an earlier American Biosatellite flight, was to understand the biomedical and biological effects of a microgravity environment using the non-human primate as human surrogate. The SLS-3/Rhesus Project and COSMOS Primate-BIOS flights all utilized the rhesus monkey, Macaca mulatta. The ultimate objective of all flights with an animal surrogate has been to evaluate and understand biological mechanisms at both the system and cellular level, thus enabling rational effective countermeasures for future long duration human activity under microgravity conditions and enabling technical application to correction of common human physiological problems within earth's gravity, e.g., muscle strength and reloading, osteoporosis, immune deficiency diseases. Hardware developed for the SLS-3/Rhesus Project was the result of a joint effort with the French Centre National d'Etudes Spatiales (CNES) and the United States National Aeronautics and Space Administration (NASA) extending over the last decade. The flight hardware design and development required implementation of sufficient automation to insure flight crew and animal bio-isolation and maintenance with minimal impact to crew activities. A variety of hardware of varying functional capabilities was developed to support the scientific objectives of the original 22 combined French and American experiments, along with 5 Russian co-investigations, including musculoskeletal, metabolic, and behavioral studies. Unique elements of the Rhesus Research Facility (RRF) included separation of waste for daily delivery of urine and fecal samples for metabolic studies and a psychomotor test system for behavioral studies along with monitored food measurement. As in untended flights, telemetry measurements would allow monitoring of

RNA-seq analysis of mycobacteria stress response to microgravity

Data.gov (United States)

National Aeronautics and Space Administration — The aim of this work is to determine whether mycobacteria have enhanced virulence during space travel and what mechanisms they use to adapt to microgravity. M....

Stereoscopic measurements of particle dispersion in microgravity turbulent flow

Science.gov (United States)

Groszmann, Daniel Eduardo

2001-08-01

The presence of particles in turbulent flows adds complexity to an already difficult subject. The work described in this research dissertation was intended to characterize the effects of inertia, isolated from gravity, on the dispersion of solid particles in a turbulent air flow. The experiment consisted of releasing particles of various sizes in an enclosed box of fan- generated, homogenous, isotropic, and stationary turbulent airflow and examining the particle behavior in a microgravity environment. The turbulence box was characterized in ground-based experiments using laser Doppler velocimetry techniques. Microgravity was established by free-floating the experiment apparatus during the parabolic trajectory of NASA's KC-135 reduced gravity aircraft. The microgravity generally lasted about 20 seconds, with about fifty parabolas per flight and one flight per day over a testing period of four days. To cover a broad range of flow regimes of interest, particles with Stokes numbers (St) of 1 to 300 were released in the turbulence box. The three- dimensional measurements of particle motion were made using a three-camera stereo imaging system with a particle-tracking algorithm. Digital photogrammetric techniques were used to determine the particle locations in three-dimensional space from the calibrated camera images. The epipolar geometry constraint was used to identify matching particles from the three different views and a direct spatial intersection scheme determined the coordinates of particles in three-dimensional space. Using velocity and acceleration constraints, particles in a sequence of frames were matched resulting in particle tracks and dispersion measurements. The goal was to compare the dispersion of different Stokes number particles in zero gravity and decouple the effects of inertia and gravity on the dispersion. Results show that higher inertia particles disperse less in zero gravity, in agreement with current models. Particles with St ~ 200

Proceedings of the Fifth Microgravity Fluid Physics and Transport Phenomena Conference

Science.gov (United States)

Singh, Bhim S. (Editor)

2000-01-01

The Fifth Microgravity Fluid Physics and Transport Phenomena Conference provided the scientific community the opportunity to view the current scope of the Microgravity Fluid Physics and Transport Phenomena Program and research opportunities and plans for the near future. Consistent with the conference theme "Microgravity Research an Agency-Wide Asset" the conference focused not only on fundamental research but also on applications of this knowledge towards enabling future space exploration missions. The conference included 14 invited plenary talks, 61 technical paper presentations, 61 poster presentations, exhibits and a forum on emerging research themes focusing on nanotechnology and biofluid mechanics. This web-based proceeding includes the presentation and poster charts provided by the presenters of technical papers and posters that were scanned at the conference site. Abstracts of all the papers and posters are included and linked to the presentations charts. The invited and plenary speakers were not required to provide their charts and are generally not available for scanning and hence not posted. The conference program is also included.

Radiation and microgravity effects observed in the insect system Carausius morosus

International Nuclear Information System (INIS)

Reitz, G.; Buecker, H.; Lindberg, C.

1992-01-01

Among the biological problems that arise in long duration spaceflights, weightlessness and ionizing radiation appear to be the main risk factors. A precise differentiation between the effects of either energy deposition by heavy ions or microgravity alone and their combined action has succeeded for the first time with the experiment on Carausius morosus embryos flown in BIORACK during the Dl mission. It was clearly demonstrated that microgravity reduces the hatching rate and amplifies the effect of heavy ions with respect to the frequency of body anomalies. In the meantime, Carausius morosus eggs were exposed during two further spaceflights, Cosmos 1887 and 2044. The studies in these experiments were done with emphasis on the morphological differentiation during embryogenesis. The first results of the Cosmos 2044 flight of effects on hatching rate, growth kinetics, vitality and frequency of anomalies are presented and compared with those of the previous flights. These data indicate that in radiation protection an additional problem will be posed by a potential modification of radiobiological effects by microgravity. (author)

Effects of a simulated microgravity model on cell structure and function in rat testis and epididymis

Science.gov (United States)

Hadley, Jill A.; Hall, Joseph C.; O'Brien, Ami; Ball, Richard

1992-01-01

The effect of simulated microgravity on the structure and function of the testis and epididymis cells was investigated in rats subjected to 7 days of tail suspension. Results of a histological examination revealed presence of disorganized seminiferous tubules and accumulation of large multinucleated cells and spermatids in the lumen of the epididymis. In addition, decreases in the content of testis protein and in testosterone levels in the testis, the interstitial fluid, and the epididymis were observed.

Phosphoribosyl diphosphate synthetase-independent NAD de novo synthesis in Escherichia coli: a new phenotype of phosphate regulon mutants

DEFF Research Database (Denmark)

Hove-Jensen, Bjarne

1996-01-01

Phosphoribosyl diphosphate-lacking (Δprs) mutant strains of Escherichia coli require NAD, guanosine, uridine, histidine, and tryptophan for growth. NAD is required by phosphoribosyl diphosphate-lacking mutants because of lack of one of the substrates for the quinolinate phosphoribosyltransferase...... reaction, an enzyme of the NAD de novo pathway. Several NAD-independent mutants of a host from which prs had been deleted were isolated; all of them were shown to have lesions in the pstSCAB-phoU operon, in which mutations lead to derepression of the Pho regulon. In addition NAD-independent growth...... was dependent on a functional quinolinate phosphoribosyltransferase. The prs suppressor mutations led to the synthesis of a new phosphoryl compound that may act as a precursor for a new NAD biosynthetic pathway. This compound may be synthesized by the product of an unknown phosphate starvation-inducible gene...

Germination and elongation of flax in microgravity

Science.gov (United States)

Levine, Howard G.; Anderson, Ken; Boody, April; Cox, Dave; Kuznetsov, Oleg A.; Hasenstein, Karl H.

2003-01-01

This experiment was conducted as part of a risk mitigation payload aboard the Space Shuttle Atlantis on STS-101. The objectives were to test a newly developed water delivery system, and to determine the optimal combination of water volume and substrate for the imbibition and germination of flax (Linum usitatissimum) seeds in space. Two different combinations of germination paper were tested for their ability to absorb, distribute, and retain water in microgravity. A single layer of thick germination paper was compared with one layer of thin germination paper under a layer of thick paper. Paper strips were cut to fit snugly into seed cassettes, and seeds were glued to them with the micropyle ends pointing outward. Water was delivered in small increments that traveled through the paper via capillary action. Three water delivery volumes were tested, with the largest (480 microliters) outperforming the 400 microliters and 320 microliters volumes for percent germination (90.6%) and root growth (mean=4.1 mm) during the 34-hour spaceflight experiment. The ground control experiment yielded similar results, but with lower rates of germination (84.4%) and shorter root lengths (mean=2.8 mm). It is not clear if the roots emerged more quickly in microgravity and/or grew faster than the ground controls. The single layer of thick germination paper generally exhibited better overall growth than the two layered option. Significant seed position effects were observed in both the flight and ground control experiments. Overall, the design of the water delivery system, seed cassettes and the germination paper strip concept was validated as an effective method for promoting seed germination and root growth under microgravity conditions. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

Space, the final frontier: A critical review of recent experiments performed in microgravity.

Science.gov (United States)

Vandenbrink, Joshua P; Kiss, John Z

2016-02-01

Space biology provides an opportunity to study plant physiology and development in a unique microgravity environment. Recent space studies with plants have provided interesting insights into plant biology, including discovering that plants can grow seed-to-seed in microgravity, as well as identifying novel responses to light. However, spaceflight experiments are not without their challenges, including limited space, limited access, and stressors such as lack of convection and cosmic radiation. Therefore, it is important to design experiments in a way to maximize the scientific return from research conducted on orbiting platforms such as the International Space Station. Here, we provide a critical review of recent spaceflight experiments and suggest ways in which future experiments can be designed to improve the value and applicability of the results generated. These potential improvements include: utilizing in-flight controls to delineate microgravity versus other spaceflight effects, increasing scientific return via next-generation sequencing technologies, and utilizing multiple genotypes to ensure results are not unique to one genetic background. Space experiments have given us new insights into plant biology. However, to move forward, special care should be given to maximize science return in understanding both microgravity itself as well as the combinatorial effects of living in space. Copyright © 2015. Published by Elsevier Ireland Ltd.

Model of transcriptional activation by MarA in Escherichia coli.

Science.gov (United States)

Wall, Michael E; Markowitz, David A; Rosner, Judah L; Martin, Robert G

2009-12-01

The AraC family transcription factor MarA activates approximately 40 genes (the marA/soxS/rob regulon) of the Escherichia coli chromosome resulting in different levels of resistance to a wide array of antibiotics and to superoxides. Activation of marA/soxS/rob regulon promoters occurs in a well-defined order with respect to the level of MarA; however, the order of activation does not parallel the strength of MarA binding to promoter sequences. To understand this lack of correspondence, we developed a computational model of transcriptional activation in which a transcription factor either increases or decreases RNA polymerase binding, and either accelerates or retards post-binding events associated with transcription initiation. We used the model to analyze data characterizing MarA regulation of promoter activity. The model clearly explains the lack of correspondence between the order of activation and the MarA-DNA affinity and indicates that the order of activation can only be predicted using information about the strength of the full MarA-polymerase-DNA interaction. The analysis further suggests that MarA can activate without increasing polymerase binding and that activation can even involve a decrease in polymerase binding, which is opposite to the textbook model of activation by recruitment. These findings are consistent with published chromatin immunoprecipitation assays of interactions between polymerase and the E. coli chromosome. We find that activation involving decreased polymerase binding yields lower latency in gene regulation and therefore might confer a competitive advantage to cells. Our model yields insights into requirements for predicting the order of activation of a regulon and enables us to suggest that activation might involve a decrease in polymerase binding which we expect to be an important theme of gene regulation in E. coli and beyond.

Model of transcriptional activation by MarA in Escherichia coli.

Directory of Open Access Journals (Sweden)

Michael E Wall

2009-12-01

Full Text Available The AraC family transcription factor MarA activates approximately 40 genes (the marA/soxS/rob regulon of the Escherichia coli chromosome resulting in different levels of resistance to a wide array of antibiotics and to superoxides. Activation of marA/soxS/rob regulon promoters occurs in a well-defined order with respect to the level of MarA; however, the order of activation does not parallel the strength of MarA binding to promoter sequences. To understand this lack of correspondence, we developed a computational model of transcriptional activation in which a transcription factor either increases or decreases RNA polymerase binding, and either accelerates or retards post-binding events associated with transcription initiation. We used the model to analyze data characterizing MarA regulation of promoter activity. The model clearly explains the lack of correspondence between the order of activation and the MarA-DNA affinity and indicates that the order of activation can only be predicted using information about the strength of the full MarA-polymerase-DNA interaction. The analysis further suggests that MarA can activate without increasing polymerase binding and that activation can even involve a decrease in polymerase binding, which is opposite to the textbook model of activation by recruitment. These findings are consistent with published chromatin immunoprecipitation assays of interactions between polymerase and the E. coli chromosome. We find that activation involving decreased polymerase binding yields lower latency in gene regulation and therefore might confer a competitive advantage to cells. Our model yields insights into requirements for predicting the order of activation of a regulon and enables us to suggest that activation might involve a decrease in polymerase binding which we expect to be an important theme of gene regulation in E. coli and beyond.

Particle Engulfment and Pushing by Solidifying Interfaces. Pt. 2; Micro-Gravity Experiments and Theoretical Analysis

Science.gov (United States)

Stefanescu, Doru M.; Juretzko, Frank R.; Dhindaw, Brij K.; Catalina, Adrian; Sen, Subhayu; Curreri, Peter A.

1998-01-01

Results of the directional solidification experiments on Particle Engulfment and Pushing by Solidifying Interfaces (PEP) conducted on the space shuttle Columbia during the Life and Microgravity Science Mission are reported. Two pure aluminum (99.999%) 9 mm cylindrical rods, loaded with about 2 vol.% 500 micrometers diameter zirconia particles were melted and resolidified in the microgravity (microg) environment of the shuttle. One sample was processed at step-wise increased solidification velocity, while the other at step-wise decreased velocity. It was found that a pushing-to-engulfment transition (PET) occurred in the velocity range of 0.5 to 1 micrometers. This is smaller than the ground PET velocity of 1.9 to 2.4 micrometers. This demonstrates that natural convection increases the critical velocity. A previously proposed analytical model for PEP was further developed. A major effort to identify and produce data for the surface energy of various interfaces required for calculation was undertaken. The predicted critical velocity for PET was of 0.775 micrometers/s.

Effect of Simulated Microgravity on Human Brain Gray Matter and White Matter--Evidence from MRI.

Directory of Open Access Journals (Sweden)

Ke Li

Full Text Available There is limited and inconclusive evidence that space environment, especially microgravity condition, may affect microstructure of human brain. This experiment hypothesized that there would be modifications in gray matter (GM and white matter (WM of the brain due to microgravity.Eighteen male volunteers were recruited and fourteen volunteers underwent -6° head-down bed rest (HDBR for 30 days simulated microgravity. High-resolution brain anatomical imaging data and diffusion tensor imaging images were collected on a 3T MR system before and after HDBR. We applied voxel-based morphometry and tract-based spatial statistics analysis to investigate the structural changes in GM and WM of brain.We observed significant decreases of GM volume in the bilateral frontal lobes, temporal poles, parahippocampal gyrus, insula and right hippocampus, and increases of GM volume in the vermis, bilateral paracentral lobule, right precuneus gyrus, left precentral gyrus and left postcentral gyrus after HDBR. Fractional anisotropy (FA changes were also observed in multiple WM tracts.These regions showing GM changes are closely associated with the functional domains of performance, locomotion, learning, memory and coordination. Regional WM alterations may be related to brain function decline and adaption. Our findings provide the neuroanatomical evidence of brain dysfunction or plasticity in microgravity condition and a deeper insight into the cerebral mechanisms in microgravity condition.

2-D Clinostat for Simulated Microgravity Experiments with Arabidopsis Seedlings

Science.gov (United States)

Wang, Hui; Li, Xugang; Krause, Lars; Görög, Mark; Schüler, Oliver; Hauslage, Jens; Hemmersbach, Ruth; Kircher, Stefan; Lasok, Hanna; Haser, Thomas; Rapp, Katja; Schmidt, Jürgen; Yu, Xin; Pasternak, Taras; Aubry-Hivet, Dorothée; Tietz, Olaf; Dovzhenko, Alexander; Palme, Klaus; Ditengou, Franck Anicet

2016-04-01

Ground-based simulators of microgravity such as fast rotating 2-D clinostats are valuable tools to study gravity related processes. We describe here a versatile g-value-adjustable 2-D clinostat that is suitable for plant analysis. To avoid seedling adaptation to 1 g after clinorotation, we designed chambers that allow rapid fixation. A detailed protocol for fixation, RNA isolation and the analysis of selected genes is described. Using this clinostat we show that mRNA levels of LONG HYPOCOTYL 5 (HY5), MIZU-KUSSEI 1 (MIZ1) and microRNA MIR163 are down-regulated in 5-day-old Arabidopsis thaliana roots after 3 min and 6 min of clinorotation using a maximal reduced g-force of 0.02 g, hence demonstrating that this 2-D clinostat enables the characterization of early transcriptomic events during root response to microgravity. We further show that this 2-D clinostat is able to compensate the action of gravitational force as both gravitropic-dependent statolith sedimentation and subsequent auxin redistribution (monitoring D R5 r e v :: G F P reporter) are abolished when plants are clinorotated. Our results demonstrate that 2-D clinostats equipped with interchangeable growth chambers and tunable rotation velocity are suitable for studying how plants perceive and respond to simulated microgravity.

Constraining volcanic inflation at Three Sisters Volcanic Field in Oregon, USA, through microgravity and deformation modeling

Science.gov (United States)

Zurek, Jeffrey; William-Jones, Glyn; Johnson, Dan; Eggers, Al

2012-10-01

Microgravity data were collected between 2002 and 2009 at the Three Sisters Volcanic Complex, Oregon, to investigate the causes of an ongoing deformation event west of South Sister volcano. Three different conceptual models have been proposed as the causal mechanism for the deformation event: (1) hydraulic uplift due to continual injection of magma at depth, (2) pressurization of hydrothermal systems and (3) viscoelastic response to an initial pressurization at depth. The gravitational effect of continual magma injection was modeled to be 20 to 33 μGal at the center of the deformation field with volumes based on previous deformation studies. The gravity time series, however, did not detect a mass increase suggesting that a viscoelactic response of the crust is the most likely cause for the deformation from 2002 to 2009. The crust, deeper than 3 km, in the Three Sisters region was modeled as a Maxwell viscoelastic material and the results suggest a dynamic viscosity between 1018 to 5 × 1019 Pa s. This low crustal viscosity suggests that magma emplacement or stall depth is controlled by density and not the brittle ductile transition zone. Furthermore, these crustal properties and the observed geochemical composition gaps at Three Sisters can be best explained by different melt sources and limited magma mixing rather than fractional crystallization. More generally, low intrusion rates, low crustal viscosity, and multiple melt sources could also explain the whole rock compositional gaps observed at other arc volcanoes.

Change in Mouse Bone Turnover in Response to Microgravity on RR-1

Science.gov (United States)

Cheng-Campbell, Margareth A.; Blaber, Elizabeth A.; Almeida, Eduardo A. C.

2016-01-01

Mechanical unloading during spaceflight is known to adversely affect mammalian physiology. Our previous studies using the Animal Enclosure Module on short duration Shuttle missions enabled us to identify a deficit in stem cell based-tissue regeneration as being a significant concern for long-duration spaceflight. Specifically, we found that mechanical unloading in microgravity resulted in inhibition of differentiation of mesenchymal and hematopoietic stem cells in the bone marrow compartment. Also, we observed overexpression of a cell cycle arrest molecule, CDKN1ap21, in osteoprecursor cells on the bone surface, chondroprogenitors in the articular cartilage, and in myofibers attached to bone tissue. Specifically in bone tissue during both short (15-day) and long (30-day) microgravity experiments, we observed significant loss of bone tissue and structure in both the pelvis and the femur. After 15-days of microgravity on STS-131, pelvic ischium displayed a 6.23 decrease in bone fraction (p0.005) and 11.91 decrease in bone thickness (p0.002). Furthermore, during long-duration spaceflight we observed onset of an accelerated aging-like phenotype and osteoarthritic disease state indicating that stem cells within the bone tissue fail to repair and regenerate tissues in a normal manner, leading to drastic tissue alterations in response to microgravity. The Rodent Research Hardware System provides the capability to investigate these effects during long-duration experiments on the International Space Station. During the Rodent Research-1 mission 10 16-week-old female C57Bl6J mice were exposed to 37-days of microgravity. All flight animals were euthanized and frozen on orbit for future dissection. Ground (n10) and vivarium controls (n10) were housed and processed to match the flight animal timeline. During this study we collected pelvis, femur, and tibia from all animal groups to test the hypothesis that stem cell-based tissue regeneration is significantly altered after 37

Turbulent Premixed Flame Propagation in Microgravity

Science.gov (United States)

Menon, S.; Disseau, M.; Chakravarthy, V. K.; Jagoda, J.

1997-01-01

A facility in which turbulent Couette flow could be generated in a microgravity environment was designed and built. To fit into the NASA Lewis drop tower the device had to be very compact. This means that edge effects and flow re-circulation were expected to affect the flow. The flow was thoroughly investigated using LDV and was found to be largely two dimensional away from the edges with constant turbulence intensities in the core. Slight flow asymmetries are introduced by the non symmetric re-circulation of the fluid outside the test region. Belt flutter problems were remedied by adding a pair of guide plates to the belt. In general, the flow field was found to be quite similar to previously investigated Couette flows. However, turbulence levels and associated shear stresses were higher. This is probably due to the confined re-circulation zone reintroducing turbulence into the test section. An estimate of the length scales in the flow showed that the measurements were able to resolve nearly all the length scales of interest. Using a new LES method for subgrid combustion it has been demonstrated that the new procedure is computational feasible even on workstation type environment. It is found that this model is capable of capturing the propagation of the premixed names by resolving the flame in the LES grid within 2-3 grid points. In contrast, conventional LES results in numerical smearing of the flame and completely inaccurate estimate of the turbulent propagation speed. Preliminary study suggests that there is observable effect of buoyancy in the 1g environment suggesting the need for microgravity experiments of the upcoming experimental combustion studies. With the cold flow properties characterized, an identical hot flow facility is under construction. It is assumed that the turbulence properties ahead of the flame in this new device will closely match the results obtained here. This is required since the hot facility will not enable LDV measurements. The

Phase change heat transfer and bubble behavior observed on twisted wire heater geometries in microgravity

International Nuclear Information System (INIS)

Munro, Troy R.; Koeln, Justin P.; Fassmann, Andrew W.; Barnett, Robert J.; Ban, Heng

2014-01-01

Highlights: • Subcooled water boiled in microgravity on twists of thin wires. • Wire twisting creates heat transfer enhancements because of high local temperatures. • A preliminary version of a new bubble dynamics method is discussed. • A critical distance that fluid must be superheated for boiling onset is presented. - Abstract: Phase change is an effective method of transferring heat, yet its application in microgravity thermal management systems requires greater understanding of bubble behavior. To further this knowledge base, a microgravity boiling experiment was performed (floating) onboard an aircraft flying in a parabolic trajectory to study the effect of surface geometry and heat flux on phase change heat transfer in a pool of subcooled water. A special emphasis was the investigation of heat transfer enhancement caused by modifying the surface geometry through the use of a twist of three wires and a twist of four wires. A new method for bubble behavior analysis was developed to quantify bubble growth characteristics, which allows a quantitative comparison of bubble dynamics between different data sets. It was found that the surface geometry of the three-wire twist enhanced heat transfer by reducing the heat flux needed for bubble incipience and the average wire temperature in microgravity. Simulation results indicated that increased local superheating in wire crevices may be responsible for the change of bubble behavior seen as the wire geometry configuration was varied. The convective heat transfer rate, in comparison to ground experiments, was lower for microgravity at low heating rates, and higher at high heating rates. This study provides insights into the role of surface geometry on superheating behavior and presents an initial version of a new bubble behavior analysis method. Further research on these topics could lead to new designs of heater surface geometries using phase change heat transfer in microgravity applications

Development of a Methodology to Gather Seated Anthropometry in a Microgravity Environment

Science.gov (United States)

Rajulu, Sudhakar; Young, Karen; Mesloh, Miranda

2009-01-01

The Constellation Program's Crew Exploration Vehicle (CEV) is required to accommodate the full population range of crewmembers according to the anthropometry requirements stated in the Human-Systems Integration Requirement (HSIR) document (CxP70024). Seated height is one of many critical dimensions of importance to the CEV designers in determining the optimum seat configuration in the vehicle. Changes in seated height may have a large impact to the design, accommodation, and safety of the crewmembers. Seated height can change due to elongation of the spine when crewmembers are exposed to microgravity. Spinal elongation is the straightening of the natural curvature of the spine and the expansion of inter-vertebral disks. This straightening occurs due to fluid shifts in the body and the lack of compressive forces on the spinal vertebrae. Previous studies have shown that as the natural curvature of the spine straightens, an increase in overall height of 3% of stature occurs which has been the basis of the current HSIR requirements. However due to variations in the torso/leg ratio and impact of soft tissue, data is nonexistent as to how spinal elongation specifically affects the measurement of seated height. In order to obtain this data, an experiment was designed to collect spinal elongation data while in a seated posture in microgravity. The purpose of this study was to provide quantitative data that represents the amount of change that occurs in seated height due to spinal elongation in microgravity environments. Given the schedule and budget constraints of ISS and Shuttle missions and the uniqueness of the problem, a methodology had to be developed to ensure that the seated height measurements were accurately collected. Therefore, simulated microgravity evaluations were conducted to test the methodology and procedures of the experiment. This evaluation obtained seat pan pressure and seated height data to a) ensure that the lap restraint provided sufficient

Cytoskeletal stability and metabolic alterations in primary human macrophages in long-term microgravity.

Directory of Open Access Journals (Sweden)

Svantje Tauber

Full Text Available The immune system is one of the most affected systems of the human body during space flight. The cells of the immune system are exceptionally sensitive to microgravity. Thus, serious concerns arise, whether space flight associated weakening of the immune system ultimately precludes the expansion of human presence beyond the Earth's orbit. For human space flight, it is an urgent need to understand the cellular and molecular mechanisms by which altered gravity influences and changes the functions of immune cells. The CELLBOX-PRIME (= CellBox-Primary Human Macrophages in Microgravity Environment experiment investigated for the first time microgravity-associated long-term alterations in primary human macrophages, one of the most important effector cells of the immune system. The experiment was conducted in the U.S. National Laboratory on board of the International Space Station ISS using the NanoRacks laboratory and Biorack type I standard CELLBOX EUE type IV containers. Upload and download were performed with the SpaceX CRS-3 and the Dragon spaceship on April 18th, 2014 / May 18th, 2014. Surprisingly, primary human macrophages exhibited neither quantitative nor structural changes of the actin and vimentin cytoskeleton after 11 days in microgravity when compared to 1g controls. Neither CD18 or CD14 surface expression were altered in microgravity, however ICAM-1 expression was reduced. The analysis of 74 metabolites in the cell culture supernatant by GC-TOF-MS, revealed eight metabolites with significantly different quantities when compared to 1g controls. In particular, the significant increase of free fucose in the cell culture supernatant was associated with a significant decrease of cell surface-bound fucose. The reduced ICAM-1 expression and the loss of cell surface-bound fucose may contribute to functional impairments, e.g. the activation of T cells, migration and activation of the innate immune response. We assume that the surprisingly small

Electron-cytochemical study of Ca2+ in cotyledon cells of soybean seedlings grown in microgravity

Science.gov (United States)

Nedukha, O.; Brown, C. S.; Kordyum, E.; Piastuch, W. C.; Guikema, J. A. (Principal Investigator)

1999-01-01

Microgravity and horizontal clinorotation are known to cause the rearrangement of the structural-functional organization of plant cells, leading to accelerated aging. Altered gravity conditions resulted in an increase in the droplets volume in cells and the destruction of chloroplast structure in Arabidopsis thaliana plants, an enhancement of cytosolic autophagaous processes, an increase in the respiration rate and a greater number of multimolecular forms of succinate- and malate dehydrogenases in cells of the Funaria hygrometrica protonema and Chlorella vulgaris, and changes in calcium balance of cells. Because ethylene is known to be involved in cell aging and microgravity appears to speed the process, and because soybean seedlings grown in space produce higher ethylene levels we asked: 1) does an acceleration of soybean cotyledon cell development and aging occur in microgravity? 2) what roles do Ca2+ ions and the enhanced ethylene level play in these events? Therefore, the goal of our investigation was to examine of the interaction of microgravity and ethylene on the localization of Ca2+ in cotyledon mesophyll of soybean seedlings.

Study on the creation of inorganic materials using micro-gravity environment; Bisho juryoku kankyo riyo muki zairyo no sosei kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

Creation of new functional inorganic materials using micro-gravity environment was studied. Observation of an electrode interface phenomenon under micro-gravity clarified that time variation in interference fringe is dependent on current density and electrode thickness in ground experiment, while it is dependent on not electrode thickness but current density under micro-gravity. In fabrication of glass fine particles under micro-gravity, true spherical glass fine particles of 4-7{mu}m in size were obtained corresponding to a charge of 40mg by evaporation and solidification of sodium tellurate glass as raw material under micro-gravity. In fabrication of non-harmonic Pb-Zn system alloy, the homogeneous alloy texture of 5{mu}m level was observed which has never been observed in previous metal phase diagrams by fusion of 80atom%Pb-20atom%Zn mixture under micro-gravity and quenching from 500degC. On the study on fabrication of spherical semiconductor crystals, 7 spherical Si single crystals of 300{mu}m in size were obtained. 12 refs., 48 figs., 2 tabs.

Interaction between graviception and carotid baroreflex function in humans during parabolic flight-induced microgravity.

Science.gov (United States)

Ogoh, Shigehiko; Marais, Michaël; Lericollais, Romain; Denise, Pierre; Raven, Peter B; Normand, Hervé

2018-05-10

The aim of the present study was to assess carotid baroreflex (CBR) during acute changes in otolithic activity in humans. To address this question, we designed a set of experiments to identify the modulatory effects of microgravity on CBR function at a tilt angle of -2{degree sign}, which was identified to minimize changes in central blood volume during parabolic flight. During parabolic flight at 0g and 1g, CBR function curves were modelled from the heart rate (HR) and mean arterial pressure (MAP) responses to rapid pulse trains of neck pressure (NP) and neck suction (NS) ranging from +40 to -80 Torr; CBR control of HR (carotid-HR) and MAP (carotid-MAP) baroreflex function curves, respectively. The maximal gain (G max ) of both carotid-HR and carotid-MAP baroreflex function curves were augmented during microgravity compared to 1g (carotid-HR, -0.53 to -0.80 beats/min/mmHg, Pflight-induced acute change of otolithic activity may modify CBR function and identifies that the vestibular system contributes to blood pressure regulation under fluctuations in gravitational forces.

Listeria monocytogenes differential transcriptome analysis reveals temperature-dependent Agr regulation and suggests overlaps with other regulons.

Science.gov (United States)

Garmyn, Dominique; Augagneur, Yoann; Gal, Laurent; Vivant, Anne-Laure; Piveteau, Pascal

2012-01-01

Listeria monocytogenes is a ubiquitous, opportunistic pathogenic organism. Environmental adaptation requires constant regulation of gene expression. Among transcriptional regulators, AgrA is part of an auto-induction system. Temperature is an environmental cue critical for in vivo adaptation. In order to investigate how temperature may affect AgrA-dependent transcription, we compared the transcriptomes of the parental strain L. monocytogenes EGD-e and its ΔagrA mutant at the saprophytic temperature of 25°C and in vivo temperature of 37°C. Variations of transcriptome were higher at 37°C than at 25°C. Results suggested that AgrA may be involved in the regulation of nitrogen transport, amino acids, purine and pyrimidine biosynthetic pathways and phage-related functions. Deregulations resulted in a growth advantage at 37°C, but affected salt tolerance. Finally, our results suggest overlaps with PrfA, σB, σH and CodY regulons. These overlaps may suggest that through AgrA, Listeria monocytogenes integrates information on its biotic environment.

Free fall plasma-arc reactor for synthesis of carbon nanotubes in microgravity

International Nuclear Information System (INIS)

Alford, J. M.; Mason, G. R.; Feikema, D. A.

2006-01-01

High temperatures inside the plasma of a carbon arc generate strong buoyancy driven convection which has an effect on the growth and morphology of the single-walled carbon nanotubes (SWNTs). To study the effect of buoyancy on the arc process, a miniature carbon arc apparatus was designed and developed to synthesize SWNTs in a microgravity environment substantially free from buoyant convective flows. An arc reactor was operated in the 2.2 and 5.18 s drop towers at the NASA Glenn Research Center. The apparatus employed a 4 mm diameter anode and was powered by a portable battery pack capable of providing in excess of 300 A at 30 V to the arc for the duration of a 5 s drop. However, the principal result is that no dramatic difference in sample yield or composition was noted between normal gravity and 2.2 and 5 s long microgravity runs. Much longer duration microgravity time is required for SWNT's growth such as the zero-G aircraft, but more likely will need to be performed on the international space station or an orbiting spacecraft

Ring-Sheared Drop (RSD): Microgravity Module for Containerless Flow Studies

Science.gov (United States)

Gulati, Shreyash; Raghunandan, Aditya; Rasheed, Fayaz; McBride, Samantha A.; Hirsa, Amir H.

2017-02-01

Microgravity is potentially a powerful tool for investigating processes that are sensitive to the presence of solid walls, since fluid containment can be achieved by surface tension. One such process is the transformation of protein in solution into amyloid fibrils; these are protein aggregates associated with neurodegenerative diseases such as Alzheimer's and Parkinson's. In addition to solid walls, experiments with gravity are also subject to influences from sedimentation of aggregates and buoyancy-driven convection. The ring-sheared drop (RSD) module is a flow apparatus currently under development to study formation of amyloid fibrils aboard the International Space Station (ISS). A 25 mm diameter drop of protein solution will be contained by surface tension and constrained by a pair of sharp-edged tubes, forming two contact rings. Shear can be imparted by rotating one ring with the other ring kept stationary. Here we report on parabolic flights conducted to test the growth and pinning of 10 mm diameter drops of water in under 10 s of microgravity. Finite element method (FEM) based fluid dynamics computations using a commercial package (COMSOL) assisted in the design of the parabolic flight experiments. Prior to the parabolic flights, the code was validated against experiments in the lab (1 g), on the growth of sessile and pendant droplets. The simulations show good agreement with the experiments. This modeling capability will enable the development of the RSD at the 25 mm scale for the ISS.

The effect of pseudo-microgravity on the symbiosis of plants and microorganisms

Science.gov (United States)

Tomita-Yokotani, Kaori; Maki, Asano; Aoki, Toshio; Tamura, Kenji; Wada, Hidenori; Hashimoto, Hirofumi; Yamashita, Masamichi

The symbiosis of plants and microorganisms is important to conduct agriculture under space environment. However, we have less knowledge on whether this kind of symbiosis can be established under space condition. We examined the functional compounds responsible to symbiosis between rhizobiaum and Lotus japonicus as a model of symbiotic combination. The existence of the substances for their symbiosis, some flavonoids, have already been known from the study of gene expression, but the detail structures have not yet been elucidated. Pseudomicrogravity was generated by the 3D-clinorotation. Twenty flavonoids were found in the extracts of 16 days plants of Lotus japonicus grown under the normal gravity by HPLC. Content of two flavonoids among them was affected by the infection of Mesorhizobium loti to them. It has a possibility that the two flavonoids were key substances for their combination process. The productions of those flavonoids were confirmed also under the pseudo-microgravity. The amount of one flavonoid was increased by both infection of rhizobium and exposure to the normal and pseudo-micro gravity. Chemical species of these flavonoids were identified by LC- ESI/MS and spectroscopic analysis. To show the effects of pseudo-microgravity on the gene expression, enzymic activities related to the functional compounds are evaluated after the rhizobial infection.

Conceptual Design and Demonstration of Space Scale for Measuring Mass in Microgravity Environment

Directory of Open Access Journals (Sweden)

Youn-Kyu Kim

2015-12-01

Full Text Available In this study, a new idea for developing a space scale for measuring mass in a microgravity environment was proposed by using the inertial force properties of an object to measure its mass. The space scale detected the momentum change of the specimen and reference masses by using a load-cell sensor as the force transducer based on Newton’s laws of motion. In addition, the space scale calculated the specimen mass by comparing the inertial forces of the specimen and reference masses in the same acceleration field. By using this concept, a space scale with a capacity of 3 kg based on the law of momentum conservation was implemented and demonstrated under microgravity conditions onboard International Space Station (ISS with an accuracy of ±1 g. By the performance analysis on the space scale, it was verified that an instrument with a compact size could be implemented and be quickly measured with a reasonable accuracy under microgravity conditions.

Computer modeling of the dynamics of surface tension on rotating fluids in low and microgravity environments

Science.gov (United States)

Hung, R. J.; Tsao, Y. D.; Hong, B. B.; Leslie, Fred W.

1989-01-01

Time-dependent evolutions of the profile of the free surface (bubble shapes) for a cylindrical container partially filled with a Newtonian fluid of constant density, rotating about its axis of symmetry, have been studied. Numerical computations have been carried out with the following situations: (1) linear functions of spin-up and spin-down in low- and microgravity environments, (2) linear functions of increasing and decreasing gravity environments at high- and low-rotating cylinder speeds, and (3) step functions of spin-up and spin-down in a low-gravity environment.

Impact of simulated microgravity on the secretory and adhesive activity of cultured human vascular endothelial cells.

Science.gov (United States)

Rudimov, Evgeny; Buravkova, Ludmila; Pogodina, Margarita; Andrianova, Irina

by the higher level of cytokines in the medium and elevated share of CD144, ICAM-1 and VCAM-1-positive cells. Comparative analysis of the level TNF-induced secretion of IL-6 and IL-8, as well as the share of cells bearing ICAM-1 and VCAM-1, showed significant variability depending on the donors. Simultaneous exposure to simulated microgravity and proinflammatory activation did not potentiate and did not cancel the effect caused by TNF-a. In summary, our findings indicate that the simulated microgravity is not activating and additional pro-inflammatory stimulus to HUVEC in vitro model. This work was supported in part by Grant from RFBR No.12-04-31763 and Grant No.NSh-371.2014.4

Study of Co-Current and Counter-Current Gas-Liquid Two-Phase Flow Through Packed Bed in Microgravity

Science.gov (United States)

Revankar, Shripad T.

2002-11-01

The main goal of the project is to obtain new experimental data and development of models on the co-current and counter-current gas-liquid two-phase flow through a packed bed in microgravity and characterize the flow regime transition, pressure drop, void and interfacial area distribution, and liquid hold up. Experimental data will be obtained for earth gravity and microgravity conditions. Models will be developed for the prediction of flow regime transition, void fraction distribution and interfacial area concentration, which are key parameters to characterize the packed bed performance. Thus the specific objectives of the proposed research are to: (1) Develop experiments for the study of the gas liquid two-phase flow through the packed bed with three different flow combinations: co-current down flow, co-current upflow and counter current flow. (2) Develop pore scale and bed scale two-phase instrumentation for measurement of flow regime transition, void distribution and gas-liquid interfacial area concentration in the packed bed. (3) Obtain database on flow regime transition, pressure drop, void distribution, interfacial area concentration and liquid hold up as a function of bed characteristics such as bed particle size, porosity, and liquid properties such as viscosity and surface tension. (4) Develop mathematical model for flow regime transition, void fraction distribution and interfacial area concentration for co-current gas-liquid flow through the porous bed in gravity and micro gravity conditions.(4) Develop mathematical model for the flooding phenomena in counter-current gas-liquid flow through the porous bed in gravity and micro gravity conditions. The present proposal addresses the most important topic of HEDS-specific microgravity fluid physics research identified by NASA 's one of the strategic enterprises, OBPR Enterprise. The proposed project is well defined and makes efficient use of the ground-based parabolic flight research aircraft facility. The

Microgravity vertical gradient measurement in the site of VIRGO interferometric antenna (Pisa plain, Italy

Directory of Open Access Journals (Sweden)

F. Fidecaro

2008-06-01

Full Text Available The site of the European Gravitational Observatory (EGO located in the countryside near Pisa (Tuscany, Italy was investigated by a microgravity vertical gradient (MVG survey. The EGO site houses the VIRGO interferometric antenna for gravitational waves detection. The microgravity survey aims to highlight the gravity anomalies of high-frequency related to more superficial geological sources in order to obtain a detailed model of the lithologic setting of the VIRGO site, that will allow an estimate of the noise induced by seismic waves and by Newtonian interference. This paper presents the results of the gradiometric survey of 2006 in the area of the interferometric antenna. MVG measurements allow us to enhance the high frequency signal strongly associated with the shallow structures. The gradient gravity map shows a main negative pattern that seems related to the trending of the high density layer of gravel that was evidenced in geotechnical drillings executed along the orthogonal arms during the construction of the VIRGO complex. Calibrating the relationship between the vertical gradient and the depth of the gravel interface we have computed a model of gravity gradient for the whole VIRGO site, defining the 3D distribution of the top surface of this layer. This latter shows a NE-SW negative pattern that may represent a palaeo-bed alluvial of the Serchio from the Bientina River system.

Collective search by ants in microgravity

Directory of Open Access Journals (Sweden)

Stefanie M. Countryman

2015-03-01

Full Text Available The problem of collective search is a tradeoff between searching thoroughly and covering as much area as possible. This tradeoff depends on the density of searchers. Solutions to the problem of collective search are currently of much interest in robotics and in the study of distributed algorithms, for example to design ways that without central control robots can use local information to perform search and rescue operations. Ant colonies operate without central control. Because they can perceive only local, mostly chemical and tactile cues, they must search collectively to find resources and to monitor the colony's environment. Examining how ants in diverse environments solve the problem of collective search can elucidate how evolution has led to diverse forms of collective behavior. An experiment on the International Space Station in January 2014 examined how ants (Tetramorium caespitum perform collective search in microgravity. In the ISS experiment, the ants explored a small arena in which a barrier was lowered to increase the area and thus lower ant density. In microgravity, relative to ground controls, ants explored the area less thoroughly and took more convoluted paths. It appears that the difficulty of holding on to the surface interfered with the ants’ ability to search collectively. Ants frequently lost contact with the surface, but showed a remarkable ability to regain contact with the surface.

Measurement of Two-Phase Flow Characteristics Under Microgravity Conditions

Science.gov (United States)

Keshock, E. G.; Lin, C. S.; Edwards, L. G.; Knapp, J.; Harrison, M. E.; Xhang, X.

1999-01-01

This paper describes the technical approach and initial results of a test program for studying two-phase annular flow under the simulated microgravity conditions of KC-135 aircraft flights. A helical coil flow channel orientation was utilized in order to circumvent the restrictions normally associated with drop tower or aircraft flight tests with respect to two-phase flow, namely spatial restrictions preventing channel lengths of sufficient size to accurately measure pressure drops. Additionally, the helical coil geometry is of interest in itself, considering that operating in a microgravity environment vastly simplifies the two-phase flows occurring in coiled flow channels under 1-g conditions for virtually any orientation. Pressure drop measurements were made across four stainless steel coil test sections, having a range of inside tube diameters (0.95 to 1.9 cm), coil diameters (25 - 50 cm), and length-to-diameter ratios (380 - 720). High-speed video photographic flow observations were made in the transparent straight sections immediately preceding and following the coil test sections. A transparent coil of tygon tubing of 1.9 cm inside diameter was also used to obtain flow visualization information within the coil itself. Initial test data has been obtained from one set of KC-135 flight tests, along with benchmark ground tests. Preliminary results appear to indicate that accurate pressure drop data is obtainable using a helical coil geometry that may be related to straight channel flow behavior. Also, video photographic results appear to indicate that the observed slug-annular flow regime transitions agree quite reasonably with the Dukler microgravity map.

Response of SAOS-2 cells to simulated microgravity and effect of biocompatible sol-gel hybrid coatings

Science.gov (United States)

Catauro, M.; Bollino, F.; Papale, F.

2016-05-01

The health of astronauts, during space flight, is threatened by bone loss induced by microgravity, mainly attributed to an imbalance in the bone remodeling process. In the present work, the response to the microgravity of bone cells has been studied using the SAOS-2 cell line grown under the condition of weightlessness, simulated by means of a Random Positioning Machine (RPM). Cell viability after 72 h of rotation has been evaluated by means of WST-8 assay and compared to that of control cells. Although no significant difference between the two cell groups has been observed in terms of viability, F-actin staining showed that microgravity environment induces cell apoptosis and altered F-actin organization. To investigate the possibility of hindering the trend of the cells towards the death, after 72 h of rotation the cells have been seeded onto biocompatible ZrO2/PCL hybrid coatings, previously obtained using a sol-gel dip coating procedure. WST-8 assay, carried out after 24 h, showed that the materials are able to inhibit the pro-apoptotic effect of microgravity on cells.

Desert Rats 2011 Mission Simulation: Effects of Microgravity Operational Modes on Fields Geology Capabilities

Science.gov (United States)

Bleacher, Jacob E.; Hurtado, J. M., Jr.; Meyer, J. A.

2012-01-01

Desert Research and Technology Studies (DRATS) is a multi-year series of NASA tests that deploy planetary surface hardware and exercise mission and science operations in difficult conditions to advance human and robotic exploration capabilities. DRATS 2011 (Aug. 30-Sept. 9, 2011) tested strategies for human exploration of microgravity targets such as near-Earth asteroids (NEAs). Here we report the crew perspective on the impact of simulated microgravity operations on our capability to conduct field geology.

Microgravity modifies protein kinase C isoform translocation in the human monocytic cell line U937 and human peripheral blood T-cells

Science.gov (United States)

Hatton, Jason P.; Gaubert, Francois; Cazenave, Jean-Pierre; Schmitt, Didier; Hashemi, B. B. (Principal Investigator); Hughes-Fulford, M. (Principal Investigator)

2002-01-01

Individual protein kinase C (PKC) isoforms fulfill distinct roles in the regulation of the commitment to differentiation, cell cycle arrest, and apoptosis in both monocytes and T-cells. The human monocyte like cell line U937 and T-cells were exposed to microgravity, during spaceflight and the translocation (a critical step in PKC signaling) of individual isoforms to cell particulate fraction examined. PKC activating phorbol esters induced a rapid translocation of several PKC isoforms to the particulate fraction of U937 monocytes under terrestrial gravity (1 g) conditions in the laboratory. In microgravity, the translocation of PKC beta II, delta, and epsilon in response to phorbol esters was reduced in microgravity compared to 1 g, but was enhanced in weak hypergravity (1.4 g). All isoforms showed a net increase in particulate PKC following phorbol ester stimulation, except PKC delta which showed a net decrease in microgravity. In T-cells, phorbol ester induced translocation of PKC delta was reduced in microgravity, compared to 1 g, while PKC beta II translocation was not significantly different at the two g-levels. These data show that microgravity differentially alters the translocation of individual PKC isoforms in monocytes and T-cells, thus providing a partial explanation for the modifications previously observed in the activation of these cell types under microgravity.

GAS payload no. G-025: Study of liquid sloshing behaviour in microgravity

Science.gov (United States)

Gilbert, C. R.

1986-01-01

The Get Away Special (GAS) G-025, which flew on shuttle Mission 51-G, examined the behavior of a liquid in a tank under microgravity conditions. The experiment is representative of phenomena occurring in satellite tanks with liquid propellants. A reference fluid in a hemispherical model tank will be subjected to linear acceleration inputs of known levels and frequencies, and the dynamic response of the tank liquid system was recorded. Preliminary analysis of the flight data indicates that the experiment functioned perfectly. The results will validate and refine mathematical models describing the dynamic characteristics of tank-fluid systems. This will in turn support the development of future spacecraft tanks, in particular the design of propellant management devices for surface tension tanks.

A systems biology pipeline identifies new immune and disease related molecular signatures and networks in human cells during microgravity exposure.

Science.gov (United States)

Mukhopadhyay, Sayak; Saha, Rohini; Palanisamy, Anbarasi; Ghosh, Madhurima; Biswas, Anupriya; Roy, Saheli; Pal, Arijit; Sarkar, Kathakali; Bagh, Sangram

2016-05-17

Microgravity is a prominent health hazard for astronauts, yet we understand little about its effect at the molecular systems level. In this study, we have integrated a set of systems-biology tools and databases and have analysed more than 8000 molecular pathways on published global gene expression datasets of human cells in microgravity. Hundreds of new pathways have been identified with statistical confidence for each dataset and despite the difference in cell types and experiments, around 100 of the new pathways are appeared common across the datasets. They are related to reduced inflammation, autoimmunity, diabetes and asthma. We have identified downregulation of NfκB pathway via Notch1 signalling as new pathway for reduced immunity in microgravity. Induction of few cancer types including liver cancer and leukaemia and increased drug response to cancer in microgravity are also found. Increase in olfactory signal transduction is also identified. Genes, based on their expression pattern, are clustered and mathematically stable clusters are identified. The network mapping of genes within a cluster indicates the plausible functional connections in microgravity. This pipeline gives a new systems level picture of human cells under microgravity, generates testable hypothesis and may help estimating risk and developing medicine for space missions.

A systems biology pipeline identifies new immune and disease related molecular signatures and networks in human cells during microgravity exposure

Science.gov (United States)

Mukhopadhyay, Sayak; Saha, Rohini; Palanisamy, Anbarasi; Ghosh, Madhurima; Biswas, Anupriya; Roy, Saheli; Pal, Arijit; Sarkar, Kathakali; Bagh, Sangram

2016-05-01

Microgravity is a prominent health hazard for astronauts, yet we understand little about its effect at the molecular systems level. In this study, we have integrated a set of systems-biology tools and databases and have analysed more than 8000 molecular pathways on published global gene expression datasets of human cells in microgravity. Hundreds of new pathways have been identified with statistical confidence for each dataset and despite the difference in cell types and experiments, around 100 of the new pathways are appeared common across the datasets. They are related to reduced inflammation, autoimmunity, diabetes and asthma. We have identified downregulation of NfκB pathway via Notch1 signalling as new pathway for reduced immunity in microgravity. Induction of few cancer types including liver cancer and leukaemia and increased drug response to cancer in microgravity are also found. Increase in olfactory signal transduction is also identified. Genes, based on their expression pattern, are clustered and mathematically stable clusters are identified. The network mapping of genes within a cluster indicates the plausible functional connections in microgravity. This pipeline gives a new systems level picture of human cells under microgravity, generates testable hypothesis and may help estimating risk and developing medicine for space missions.

Effect of electromagnetic fields on the chondrogenic differentiation under microgravity conditions

Data.gov (United States)

National Aeronautics and Space Administration — A combination therapy of electromagnetic fields (EMF) and simulated microgravity (SMG) has not been examined in regenerative medicine of cartilage. In the present...

Concurrent Flame Growth, Spread and Extinction over Composite Fabric Samples in Low Speed Purely Forced Flow in Microgravity

Science.gov (United States)

Zhao, Xiaoyang; T'ien, James S.; Ferkul, Paul V.; Olson, Sandra L.

2015-01-01

As a part of the NASA BASS and BASS-II experimental projects aboard the International Space Station, flame growth, spread and extinction over a composite cotton-fiberglass fabric blend (referred to as the SIBAL fabric) were studied in low-speed concurrent forced flows. The tests were conducted in a small flow duct within the Microgravity Science Glovebox. The fuel samples measured 1.2 and 2.2 cm wide and 10 cm long. Ambient oxygen was varied from 21% down to 16% and flow speed from 40 cm/s down to 1 cm/s. A small flame resulted at low flow, enabling us to observe the entire history of flame development including ignition, flame growth, steady spread (in some cases) and decay at the end of the sample. In addition, by decreasing flow velocity during some of the tests, low-speed flame quenching extinction limits were found as a function of oxygen percentage. The quenching speeds were found to be between 1 and 5 cm/s with higher speed in lower oxygen atmosphere. The shape of the quenching boundary supports the prediction by earlier theoretical models. These long duration microgravity experiments provide a rare opportunity for solid fuel combustion since microgravity time in ground-based facilities is generally not sufficient. This is the first time that a low-speed quenching boundary in concurrent spread is determined in a clean and unambiguous manner.

Perspectives of experimental and theoretical studies of self-organized dust structures in complex plasmas under microgravity conditions

International Nuclear Information System (INIS)

Tsytovich, V N

2015-01-01

We review research aimed at understanding the phenomena occurring in a complex plasma under microgravity conditions. Some aspects of the work already performed are considered that have not previously been given sufficient attention but which are potentially crucial for future work. These aspects, in particular, include the observation of compact dust structures that are estimated to be capable of confining all components of a dust plasma in a bounded spatial volume; experimental evidence of the nonlinear screening of dust particles; and experimental evidence of the excitation of collective electric fields. In theoretical terms, novel collective attraction processes between likely charged dust particles are discussed and all schemes of the shadowy attraction between dust particles used earlier, including in attempts to interpret observations, are reviewed and evaluated. Dust structures are considered from the standpoint of the current self-organization theory. It is emphasized that phase transitions between states of self-organized systems differ significantly from those in homogeneous states and that the phase diagrams should be constructed in terms of the parameters of a self-organized structure and cannot be constructed in terms of the temperature and density or similar parameters of homogeneous structures. Using the existing theoretical approaches to modeling self-organized structures in dust plasmas, the parameter distribution of a structure is recalculated for a simpler model that includes the quasineutrality condition and neglects diffusion. These calculations indicate that under microgravity conditions, any self-organized structure can contain a limited number of dust particles and is finite in size. The maximum possible number of particles in a structure determines the characteristic inter-grain distance in dust crystals that can be created under microgravity conditions. Crystallization criteria for the structures are examined and the quasispherical

Subjective Straight Ahead Orientation in Microgravity

Science.gov (United States)

Clement, G.; Reschke, M. F.; Wood, S. J.

2015-01-01

This joint ESA NASA study will address adaptive changes in spatial orientation related to the subjective straight ahead and the use of a vibrotactile sensory aid to reduce perceptual errors. The study will be conducted before and after long-duration expeditions to the International Space Station (ISS) to examine how spatial processing of target location is altered following exposure to microgravity. This study addresses the sensorimotor research gap to "determine the changes in sensorimotor function over the course of a mission and during recovery after landing."

Investigation of cerebral venous outflow in microgravity.

Science.gov (United States)

Taibi, A; Gadda, G; Gambaccini, M; Menegatti, E; Sisini, F; Zamboni, P

2017-10-31

The gravitational gradient is the major component to face when considering the physiology of venous return, and there is a growing interest in understanding the mechanisms ensuring the heart filling, in the absence of gravity, for astronauts who perform long-term space missions. The purpose of the Drain Brain project was to monitor the cerebral venous outflow of a crew member during an experiment on the International Space Station (ISS), so as to study the compensatory mechanisms that facilitate this essential physiological action in subjects living in a microgravity environment. Such venous function has been characterized by means of a novel application of strain-gauge plethysmography which uses a capacitive sensor. In this contribution, preliminary results of our investigation have been presented. In particular, comparison of plethysmography data confirmed that long duration spaceflights lead to a redistribution of venous blood volume, and showed interesting differences in the amplitude of cardiac oscillations measured at the level of the neck veins. The success of the experiment has also demonstrated that thanks to its easy portability, non-invasiveness, and non-operator dependence, the proposed device can be considered as a novel tool for use aboard the ISS. Further trials are now under way to complete the investigation on the drainage function of the neck veins in microgravity.

A hydroponic method for plant growth in microgravity

Science.gov (United States)

Wright, B. D.

1985-01-01

A hydroponic apparatus under development for long-term microgravity plant growth is described. The capillary effect root environment system (CERES) is designed to keep separate the nutrient and air flows, although both must be simultaneously available to the roots. Water at a pressure slightly under air pressure is allowed to seep into a plastic depression covered by a plastic screen and a porous membrane. A root in the air on the membrane outer surface draws the moisture through it. The laboratory model has a wire-based 1.241 mm mesh polyethylene screen and a filter membrane with 0.45 micron pores, small enough to prohibit root hair penetration. The design eliminates the need to seal-off the plant environment. Problems still needing attention include scaling up of the CERES size, controlling biofouling of the membrane, and extending the applications to plants without fibrous root systems.

Robust Control for Microgravity Vibration Isolation using Fixed Order, Mixed H2/Mu Design

Science.gov (United States)

Whorton, Mark

2003-01-01

Many space-science experiments need an active isolation system to provide a sufficiently quiescent microgravity environment. Modern control methods provide the potential for both high-performance and robust stability in the presence of parametric uncertainties that are characteristic of microgravity vibration isolation systems. While H2 and H(infinity) methods are well established, neither provides the levels of attenuation performance and robust stability in a compensator with low order. Mixed H2/H(infinity), controllers provide a means for maximizing robust stability for a given level of mean-square nominal performance while directly optimizing for controller order constraints. This paper demonstrates the benefit of mixed norm design from the perspective of robustness to parametric uncertainties and controller order for microgravity vibration isolation. A nominal performance metric analogous to the mu measure, for robust stability assessment is also introduced in order to define an acceptable trade space from which different control methodologies can be compared.

Transcriptomics analysis of etiolated Arabidopsis thaliana seedlings in response to microgravity

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National Aeronautics and Space Administration — Gene expression profile of two-week-old etiolated Arabidopsis seedlings under microgravity on board space flight BRIC16 were compared with ground grown control in...

Thyrotropin Receptor and Membrane Interactions in FRTL-5 Thyroid Cell Strain in Microgravity

Science.gov (United States)

Albi, E.; Ambesi-Impiombato, F. S.; Peverini, M.; Damaskopoulou, E.; Fontanini, E.; Lazzarini, R.; Curcio, F.; Perrella, G.

2011-01-01

The aim of this work was to analyze the possible alteration of thyrotropin (TSH) receptors in microgravity, which could explain the absence of thyroid cell proliferation in the space environment. Several forms of the TSH receptor are localized on the plasma membrane associated with caveolae and lipid rafts. The TSH regulates the fluidity of the cell membrane and the presence of its receptors in microdomains that are rich in sphingomyelin and cholesterol. TSH also stimulates cyclic adenosine monophosphate (cAMP) accumulation and cell proliferation. Reported here are the results of an experiment in which the FRTL-5 thyroid cell line was exposed to microgravity during the Texus-44 mission (launched February 7, 2008, from Kiruna, Sweden). When the parabolic flight brought the sounding rocket to an altitude of 264km, the culture media were injected with or without TSH in the different samples, and weightlessness prevailed on board for 6 minutes and 19 seconds. Control experiments were performed, in parallel, in an onboard 1g centrifuge and on the ground in Kiruna laboratory. Cell morphology and function were analyzed. Results show that in microgravity conditions the cells do not respond to TSH treatment and present an irregular shape with condensed chromatin, a modification of the cell membrane with shedding of the TSH receptor in the culture medium, and an increase of sphingomyelin-synthase and Bax proteins. It is possible that real microgravity induces a rearrangement of specific sections of the cell membrane, which act as platforms for molecular receptors, thus influencing thyroid cell function in astronauts during space missions.

Effect of microgravity on stress ethylene and carbon dioxide production in sweet clover (Melilotus alba L.)

Science.gov (United States)

Gallegos, Gregory L.; Odom, William R.; Guikema, James A.

1995-01-01

The study of higher plant growth and development in the microgravity (micro-g) environment continues to be a challenge. This is in part a result of the available flight qualified hardware with restrictive closed gas environments. This point is underscored by considering that gas exchange of seedlings grown in microgravity may be further limited owing to a thicker layer of water wicked onto the roots and to the absence of convective mixing. We hypothesized that seedlings grown under such conditions will experience greater hypoxia in microgravity than at Earth gravity, and thus produce greater stress ethylene. We compared flight and ground samples of sweet clover seedlings grown in the Fluid Processing Apparatus (FPA) during STS-57 and found them to contain extremely high levels of carbon dioxide (CO2) and stress ethylene. There were time dependent increases for both gases, and seedling growth was greatly inhibited. We repeated these experiments aboard STS-60 using modified chambers which increased, by fifty fold, the air available to the developing seedlings. Sweet clover seed germination and subsequent seedling growth to eight days within the FPA modified with a gas permeable membrane is not compromised by the microgravity environment.

The Transcriptional Response of Diverse Saccharomyces cerevisiae Strains to Simulated Microgravity

Science.gov (United States)

Neff, Lily S.; Fleury, Samantha T.; Galazka, Jonathan M.

2018-01-01

Spaceflight imposes multiple stresses on biological systems resulting in genome-scale adaptations. Understanding these adaptations and their underlying molecular mechanisms is important to clarifying and reducing the risks associated with spaceflight. One such risk is infection by microbes present in spacecraft and their associated systems and inhabitants. This risk is compounded by results suggesting that some microbes may exhibit increased virulence after exposure to spaceflight conditions. The yeast, S. cerevisiae, is a powerful microbial model system, and its response to spaceflight has been studied for decades. However, to date, these studies have utilized common lab strains. Yet studies on trait variation in S. cerevisiae demonstrate that these lab strains are not representative of wild yeast and instead respond to environmental stimuli in an atypical manner. Thus, it is not clear how transferable these results are to the wild S. cerevisiae strains likely to be encountered during spaceflight. To determine if diverse S. cerevisiae strains exhibit a conserved response to simulated microgravity, we will utilize a collection of 100 S. cerevisiae strains isolated from clinical, environmental and industrial settings. We will place selected S. cerevisiae strains in simulated microgravity using a high-aspect rotating vessel (HARV) and document their transcriptional response by RNA-sequencing and quantify similarities and differences between strains. Our research will have a strong impact on the understanding of how genetic diversity of microorganisms effects their response to spaceflight, and will serve as a platform for further studies.

Effect of simulated microgravity on growth and production of exopolymeric substances of Micrococcus luteus space and earth isolates.

Science.gov (United States)

Mauclaire, Laurie; Egli, Marcel

2010-08-01

Microorganisms tend to form biofilms on surfaces, thereby causing deterioration of the underlaying material. In addition, biofilm is a potential health risk to humans. Therefore, microorganism growth is not only an issue on Earth but also in manned space habitats like the International Space Station (ISS). The aim of the study was to identify physiological processes relevant for Micrococcus luteus attachment under microgravity conditions. The results demonstrate that simulated microgravity influences physiological processes which trigger bacterial attachment and biofilm formation. The ISS strains produced larger amounts of exopolymeric substances (EPS) compared with a reference strain from Earth. In contrast, M. luteus strains were growing faster, and Earth as well as ISS isolates produced a higher yield of biomass under microgravity conditions than under normal gravity. Furthermore, microgravity caused a reduction of the colloidal EPS production of ISS isolates in comparison with normal gravity, which probably influences biofilm thickness and stability as well.

X-Ray Radiographic Observation of Directional Solidification Under Microgravity: XRMON-GF Experiments on MASER12 Sounding Rocket Mission

Science.gov (United States)

Reinhart, G.; NguyenThi, H.; Bogno, A.; Billia, B.; Houltz, Y.; Loth, K.; Voss, D.; Verga, A.; dePascale, F.; Mathiesen, R. H.;

Plant cell transformation with Agrobacterium tumefaciens under simulated microgravity

Science.gov (United States)

Sarnatska, Veresa; Gladun, Hanna; Padalko, Svetlana

To investigate simulated microgravity (clinorotation) effect on plant cell transformation with Agrobacterium tumefaciens and crown gall formation, the culture of primary explants of potato and Jerusalem artichoke tubers was used. It is found that the efficiency of tumor formation and development in clinorotated explants are considerably reduced. When using the explants isolated from potato tubers clinorotated for 3, 5 and 19 days, drastic reduction of formation and development of crown gall tumors was observed. Conversely, the tumor number and their development increased when potato tubers were clinorotated for one day. As was estimated by us previously, cells of Jerusalem artichoke explants are the most sensitive to agrobacteria on 4-5 h of in vitro culturing and this time corresponds to the certain period of G1-stage of the cell cycle. We have also estimated that this period is characterized by the increase of binding of acridine orange by nuclear chromatin and increase in activity of RNA-polymerase I and II. Inoculation of explants with agrobacteria in this period was the most optimal for transformation and crown gall induction. We estimated that at four - hour clinorotation of explants the intensity of acridine orange binding to nuclei was considerably lower than on 4h in the control. At one-day clinorotation of potato tubers, a considerable increase in template accessibility of chromatin and in activity of RNA-polymerase I and II occurred. These results may serve as an evidence for the ability of plant dormant tissues to respond to microgravity. Another demonstration of dormant tissue response to changed gravity we obtained when investigating pathogenesis-related proteins (PR-proteins). PR-proteins were subjected to nondenaturing PAGE.and we have not found any effect of microgravity on PR-proteins of potato explants with normal or tumorous growth. We may suggest that such response derives from the common effects of two stress factors - wounding and changed

Characterization of Escherichia coli MG1655 grown in a low-shear modeled microgravity environment

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Pierson Duane L

2007-03-01

Full Text Available Abstract Background Extra-cellular shear force is an important environmental parameter that is significant both medically and in the space environment. Escherichia coli cells grown in a low-shear modeled microgravity (LSMMG environment produced in a high aspect rotating vessel (HARV were subjected to transcriptional and physiological analysis. Results Aerobic LSMMG cultures were grown in rich (LB and minimal (MOPS + glucose medium with a normal gravity vector HARV control. Reproducible changes in transcription were seen, but no specific LSMMG responsive genes were identified. Instead, absence of shear and a randomized gravity vector appears to cause local extra-cellular environmental changes, which elicit reproducible cellular responses. In minimal media, the majority of the significantly up- or down-regulated genes of known function were associated with the cell envelope. In rich medium, most LSMMG down-regulated genes were involved in translation. No observable changes in post-culture stress responses and antibiotic sensitivity were seen in cells immediately after exposure to LSMMG. Comparison with earlier studies of Salmonella enterica serovar Typhimurium conducted under similar growth conditions, revealed essentially no similarity in the genes that were significantly up- or down-regulated. Conclusion Comparison of these results to previous studies suggests that different organisms may dramatically differ in their responses to medically significant low-shear and space environments. Depending on their specific response, some organisms, such as Salmonella, may become preadapted in a manner that predisposes them to increased virulence.

Optimization of Photosynthetic Productivity in Contrasting Environments by Regulons Controlling Plant Form and Function

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Barbara Demmig-Adams

2018-03-01

Full Text Available We review the role of a family of transcription factors and their regulons in maintaining high photosynthetic performance across a range of challenging environments with a focus on extreme temperatures and water availability. Specifically, these transcription factors include CBFs (C-repeat binding factors and DREBs (dehydration-responsive element-binding, with CBF/DREB1 primarily orchestrating cold adaptation and other DREBs serving in heat, drought, and salinity adaptation. The central role of these modulators in plant performance under challenging environments is based on (i interweaving of these regulators with other key signaling networks (plant hormones and redox signals as well as (ii their function in integrating responses across the whole plant, from light-harvesting and sugar-production in the leaf to foliar sugar export and water import and on to the plant’s sugar-consuming sinks (growth, storage, and reproduction. The example of Arabidopsis thaliana ecotypes from geographic origins with contrasting climates is used to describe the links between natural genetic variation in CBF transcription factors and the differential acclimation of plant anatomical and functional features needed to support superior photosynthetic performance in contrasting environments. Emphasis is placed on considering different temperature environments (hot versus cold and light environments (limiting versus high light, on trade-offs between adaptations to contrasting environments, and on plant lines minimizing such trade-offs.

Microgravity cultivation of cells and tissues

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Freed, L. E.; Pellis, N.; Searby, N.; de Luis, J.; Preda, C.; Bordonaro, J.; Vunjak-Novakovic, G.

1999-01-01

In vitro studies of cells and tissues in microgravity, either simulated by cultivation conditions on earth or actual, during spaceflight, are expected to help identify mechanisms underlying gravity sensing and transduction in biological organisms. In this paper, we review rotating bioreactor studies of engineered skeletal and cardiovascular tissues carried out in unit gravity, a four month long cartilage tissue engineering study carried out aboard the Mir Space Station, and the ongoing laboratory development and testing of a system for cell and tissue cultivation aboard the International Space Station.

Verification of the Microgravity Active Vibration Isolation System based on Parabolic Flight

Science.gov (United States)

Zhang, Yong-kang; Dong, Wen-bo; Liu, Wei; Li, Zong-feng; Lv, Shi-meng; Sang, Xiao-ru; Yang, Yang

2017-12-01

The Microgravity active vibration isolation system (MAIS) is a device to reduce on-orbit vibration and to provide a lower gravity level for certain scientific experiments. MAIS system is made up of a stator and a floater, the stator is fixed on the spacecraft, and the floater is suspended by electromagnetic force so as to reduce the vibration from the stator. The system has 3 position sensors, 3 accelerometers, 8 Lorentz actuators, signal processing circuits and a central controller embedded in the operating software and control algorithms. For the experiments on parabolic flights, a laptop is added to MAIS for monitoring and operation, and a power module is for electric power converting. The principle of MAIS is as follows: the system samples the vibration acceleration of the floater from accelerometers, measures the displacement between stator and floater from position sensitive detectors, and computes Lorentz force current for each actuator so as to eliminate the vibration of the scientific payload, and meanwhile to avoid crashing between the stator and the floater. This is a motion control technic in 6 degrees of freedom (6-DOF) and its function could only be verified in a microgravity environment. Thanks for DLR and Novespace, we get a chance to take the DLR 27th parabolic flight campaign to make experiments to verify the 6-DOF control technic. The experiment results validate that the 6-DOF motion control technique is effective, and vibration isolation performance perfectly matches what we expected based on theoretical analysis and simulation. The MAIS has been planned on Chinese manned spacecraft for many microgravity scientific experiments, and the verification on parabolic flights is very important for its following mission. Additionally, we also test some additional function by microgravity electromagnetic suspension, such as automatic catching and locking and working in fault mode. The parabolic flight produces much useful data for these experiments.

uG-LilyPond - Floating Plant Pond for Microgravity, Phase I

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National Aeronautics and Space Administration — The proposed μG-LilyPond is an autonomous environmentally controlled floating plant cultivation system for use in microgravity. The μG-LilyPond concept expands the...

Microgravity as a biological tool to examine host-pathogen interactions and to guide development of therapeutics and preventatives that target pathogenic bacteria.

Science.gov (United States)

Higginson, Ellen E; Galen, James E; Levine, Myron M; Tennant, Sharon M

2016-11-01

Space exploration programs have long been interested in the effects of spaceflight on biology. This research is important not only in its relevance to future deep space exploration, but also because it has allowed investigators to ask questions about how gravity impacts cell behavior here on Earth. In the 1980s, scientists designed and built the first rotating wall vessel, capable of mimicking the low shear environment found in space. This vessel has since been used to investigate growth of both microorganisms and human tissue cells in low shear modeled microgravity conditions. Bacterial behavior has been shown to be altered both in space and under simulated microgravity conditions. In some cases, bacteria appear attenuated, whereas in others virulence is enhanced. This has consequences not only for manned spaceflight, but poses larger questions about the ability of bacteria to sense the world around them. By using the microgravity environment as a tool, we can exploit this phenomenon in the search for new therapeutics and preventatives against pathogenic bacteria for use both in space and on Earth. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Risk Assessment and Control through Countermeasure System Iplementation for Long-term Crew Exposure to Microgravity

Science.gov (United States)

Gernand, Jeremy M.

2004-01-01

Experience with the International Space Station (ISS) program demonstrates the degree to which engineering design and operational solutions must protect crewmembers from health risks due to long-term exposure to the microgravity environment. Risks to safety and health due to degradation in the microgravity environment include crew inability to complete emergency or nominal activities, increased risk of injury, and inability to complete safe return to the ground due to reduced strength or embrittled bones. These risks without controls slowly increase in probability for the length of the mission and become more significant for increasing mission durations. Countermeasures to microgravity include hardware systems that place a crewmember s body under elevated stress to produce an effect similar to daily exposure to gravity. The ISS countermeasure system is predominately composed of customized exercise machines. Historical treatment of microgravity countermeasure systems as medical research experiments unintentionally reduced the foreseen importance and therefore the capability of the systems to function in a long-term operational role. Long-term hazardous effects and steadily increasing operational risks due to non-functional countermeasure equipment require a more rigorous design approach and incorporation of redundancy into seemingly non- mission-critical hardware systems. Variations in the rate of health degradation and responsiveness to countermeasures among the crew population drastically increase the challenge for design requirements development and verification of the appropriate risk control strategy. The long-term nature of the hazards and severe limits on logistical re-supply mass, volume and frequency complicates assessment of hardware availability and verification of an adequate maintenance and sparing plan. Design achievement of medically defined performance requirements by microgravity countermeasure systems and incorporation of adequate failure tolerance

The Low Temperature Microgravity Physics Experiments Project

Science.gov (United States)

Holmes, Warren; Lai, Anthony; Croonquist, Arvid; Chui, Talso; Eraker, J. H.; Abbott, Randy; Mills, Gary; Mohl, James; Craig, James; Balachandra, Balu;

Theoretical analysis of the particle properties and polarization measurements made in microgravity

International Nuclear Information System (INIS)

Penttilae, A.; Lumme, K.; Worms, J.C.; Hadamcik, E.; Renard, J.B.; Levasseur-Regourd, A.C.

2003-01-01

We propose a new model to describe the shapes of stochastic polyhedra used in the microgravity experiment PROGRA 2 on board the Airbus A300 aircraft. The polarization measurements of scattering of visible light by boron carbide (B 4 C) particles with sizes between 9 and 88 μm can nicely be explained with the derived shape statistics and the (currently unknown) refractive index obtained. For the latter we derive 2 (-0.15/+0.1)+0.04i(-0.0025/+0.015) at 632.8 nm wavelength. The polarization method is a reliable and sensitive means to estimate various particle properties in various remote sensing applications, including the planetary sciences

Self-rotations in simulated microgravity: performance effects of strategy training.

Science.gov (United States)

Stirling, Leia; Newman, Dava; Willcox, Karen

2009-01-01

This research studies reorientation methodologies in a simulated microgravity environment using an experimental framework to reduce astronaut adaptation time and provide for a safety countermeasure during extravehicular activity. There were 20 subjects (10 men, 10 women, mean age of 23.6 +/- 3.5) who were divided into 2 groups, fully trained and minimally trained, which determined the amount of motion strategy training received. Subjects performed a total of 48 rotations about their pitch, roll, and yaw axes in a suspension system that simulated microgravity. In each trial subjects either rotated 90 degrees in pitch, 90 degrees in roll, or 180 degrees in yaw. Experimental measures include subject coordination, performance time, cognitive workload assessments, and qualitative motion control strategies. Subjects in the fully trained group had better initial performance with respect to performance time and workload scores for the pitch and yaw rotations. Further, trained subjects reached a steady-state performance time in fewer trials than those with minimal training. The subjects with minimal training tended to use motions that were common in an Earth environment since no technique was provided. For roll rotations they developed motions that would have led to significant off-axis (pitch and yaw) rotations in a true microgravity environment. We have shown that certain body axes are easier to rotate about than others and that fully trained subjects had an easier time performing the body rotations than the minimally trained subjects. This study has provided the groundwork for the development of an astronaut motion-control training program.

Methanol Droplet Extinction in Oxygen/Carbon-dioxide/Nitrogen Mixtures in Microgravity: Results from the International Space Station Experiments

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Nayagam, Vedha; Dietrich, Daniel L.; Ferkul, Paul V.; Hicks, Michael C.; Williams, Forman A.

2012-01-01

Motivated by the need to understand the flammability limits of condensed-phase fuels in microgravity, isolated single droplet combustion experiments were carried out in the Combustion Integrated Rack Facility onboard the International Space Station. Experimental observations of methanol droplet combustion and extinction in oxygen/carbon-dioxide/nitrogen mixtures at 0.7 and 1 atmospheric pressure in quiescent microgravity environment are reported for initial droplet diameters varying between 2 mm to 4 mm in this study.The ambient oxygen concentration was systematically lowered from test to test so as to approach the limiting oxygen index (LOI) at fixed ambient pressure. At one atmosphere pressure, ignition and some burning were observed for an oxygen concentration of 13% with the rest being nitrogen. In addition, measured droplet burning rates, flame stand-off ratios, and extinction diameters are presented for varying concentrations of oxygen and diluents. Simplified theoretical models are presented to explain the observed variations in extinction diameter and flame stand-off ratios.

Active transmembrane drug transport in microgravity: a validation study using an ABC transporter model [v1; ref status: indexed, http://f1000r.es/41n

Directory of Open Access Journals (Sweden)

Sergi Vaquer

2014-08-01

Full Text Available Abstract Microgravity has been shown to influence the expression of ABC (ATP-Binding Cassette transporters in bacteria, fungi and mammals, but also to modify the activity of certain cellular components with structural and functional similarities to ABC transporters. Changes in activity of ABC transporters could lead to important metabolic disorders and undesired pharmacological effects during spaceflights. However, no current means exist to study the functionality of these transporters in microgravity. To this end, a Vesicular Transport Assay® (Solvo Biotechnology, Hungary was adapted to evaluate multi-drug resistance-associated protein 2 (MRP2 trans-membrane estradiol-17-β-glucuronide (E17βG transport activity, when activated by adenosine-tri-phosphate (ATP during parabolic flights. Simple diffusion, ATP-independent transport and benzbromarone inhibition were also evaluated. A high accuracy engineering system was designed to perform, monitor and synchronize all procedures. Samples were analysed using a validated high sensitivity drug detection protocol. Experiments were performed in microgravity during parabolic flights, and compared to 1g on ground results using identical equipment and procedures in all cases. Our results revealed that sufficient equipment accuracy and analytical sensitivity were reached to detect transport activity in both gravitational conditions. Additionally, transport activity levels of on ground samples were within commercial transport standards, proving the validity of the methods and equipment used. MRP2 net transport activity was significantly reduced in microgravity, so was signal detected in simple diffusion samples. Ultra-structural changes induced by gravitational stress upon vesicle membranes or transporters could explain the current results, although alternative explanations are possible. Further research is needed to provide a conclusive answer in this regard. Nevertheless, the present validated technology

Determining the effect of turbulent shear on containment aerosol dynamics using microgravity experiments

International Nuclear Information System (INIS)

Scott, C.K.; Abdelbaky, M.

1997-01-01

Determining the characteristics of large aerosol aggregates 'clusters' under turbulent conditions is fundamental for predicting the behaviour of radioactive aerosols inside the reactor containment following a severe accident. Studying such rapidly settling clusters is extremely difficult in ground-based experiments due to the effect of the earth's gravity. In this study, the microgravity environment is exploited to investigate the effect of turbulent shear on the aggregation and breakage of clusters by examining their structure and measuring their strength parameters while suspended under weightlessness conditions. A parametric model is introduced to correlate the experimental results over into nuclear aerosol models. It was demonstrated that the cluster parameters depend mainly on the turbulent field intensity as well as initial powder conditions. (author)

Microgravity induces proteomics changes involved in endoplasmic reticulum stress and mitochondrial protection

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National Aeronautics and Space Administration — To reveal outcomes of microgravity on molecular processes within the cellular environment we have employed a mass-spectrometry based proteomics approach. Proteomics...

T Cell Activation in Microgravity Compared to 1g (Earth s) Gravity

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National Aeronautics and Space Administration — This study tested the hypothesis that transcription of immediate early genes is inhibited in T cells activated in microgravity (mg). Immunosuppression during...

Effects of simulated microgravity on gene expression and biological phenotypes of a single generation Caenorhabditis elegans cultured on 2 different media.

Science.gov (United States)

Tee, Ling Fei; Neoh, Hui-Min; Then, Sue Mian; Murad, Nor Azian; Asillam, Mohd Fairos; Hashim, Mohd Helmy; Nathan, Sheila; Jamal, Rahman

2017-11-01

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. Usage of different culture media during microgravity simulation experiments might also give rise to differences in the gene expression and biological phenotypes of the worms. In this study, we investigated the effects of simulated microgravity on the gene expression and biological phenotype profiles of a single generation of C. elegans worms cultured on 2 different culture media. A desktop Random Positioning Machine (RPM) was used to simulate microgravity on the worms for approximately 52 to 54 h. Gene expression profile was analysed using the Affymetrix GeneChip® C. elegans 1.0 ST Array. Only one gene (R01H2.2) was found to be downregulated in nematode growth medium (NGM)-cultured worms exposed to simulated microgravity. On the other hand, eight genes were differentially expressed for C. elegans Maintenance Medium (CeMM)-cultured worms in microgravity; six were upregulated, while two were downregulated. Five of the upregulated genes (C07E3.15, C34H3.21, C32D5.16, F35H8.9 and C34F11.17) encode non-coding RNAs. In terms of biological phenotype, we observed that microgravity-simulated worms experienced minimal changes in terms of lifespan, locomotion and reproductive capabilities in comparison with the ground controls. Taking it all together, simulated microgravity on a single generation of C. elegans did not confer major changes to their gene expression and biological phenotype. Nevertheless, exposure of the worms to microgravity

Long-Term Evolution Studies of E. Coli under Combined Effects of Simulated Microgravity and Antibiotic.

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Karouia, Fathi; Tirumalai, Madhan R.; Ott, Mark C.; Pierson, Duane L.; Fox, George E.; Tran, Quyen

2016-07-01

Multiple spaceflight and simulated microgravity experiments have shown changes in phenotypic microbial characteristics such as microbial growth, morphology, metabolism, genetic transfer, antibiotic and stress susceptibility, and an increase in virulence factors. However, while these studies have contributed to expand our understanding of the short-term effects of spaceflight or simulated microgravity on biological systems, it remains unclear the type of responses subsequent to long-term exposure to space environment and microgravity in particular. As such, organisms exposed to the space environment for extended periods of time may evolve in unanticipated ways thereby negatively impacting long duration space missions. We report here for the first time, an experimental study of microbial evolution in which the effect of long-term exposure to Low Shear Modeled MicroGravity (LSMMG) on microbial gene expression and physiology in Escherichia coli (E. coli) MG1655 was examined using functional genomics, and molecular techniques with and without simultaneous exposure to broad spectrum antibiotic chloramphenicol. E. coli cells were grown under simulated microgravity for 1000 generations in High Aspect Ratio Vessels (HARVs) that were either heat-sterilized (115 deg C, 15 min) or by using/rinsing the HARVs with a saturated solution of the broad-spectrum antibiotic chloramphenicol. In the case of the cells evolved using the antibiotic sterilized HARVs, the expression levels of 357 genes were significantly changed. In particular, fimbriae encoding genes were significantly up-regulated whereas genes encoding the flagellar motor complex were down-regulated. Re-sequencing of the genome revealed that a number of the flagellar genes were actually deleted. The antibiotic resistance levels of the evolved strains were analyzed using VITEK analyzer. The evolved strain was consistently resistant to the antibiotics used (viz., Ampicillin, Cefalotin, Cefurox-ime, Cefuroxime Axetil

Microgravity Active Vibration Isolation System on Parabolic Flights

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Dong, Wenbo; Pletser, Vladimir; Yang, Yang

2016-07-01

The Microgravity Active Vibration Isolation System (MAIS) aims at reducing on-orbit vibrations, providing a better controlled lower gravity environment for microgravity physical science experiments. The MAIS will be launched on Tianzhou-1, the first cargo ship of the China Manned Space Program. The principle of the MAIS is to suspend with electro-magnetic actuators a scientific payload, isolating it from the vibrating stator. The MAIS's vibration isolation capability is frequency-dependent and a decrease of vibration of about 40dB can be attained. The MAIS can accommodate 20kg of scientific payload or sample unit, and provide 30W of power and 1Mbps of data transmission. The MAIS is developed to support microgravity scientific experiments on manned platforms in low earth orbit, in order to meet the scientific requirements for fluid physics, materials science, and fundamental physics investigations, which usually need a very quiet environment, increasing their chances of success and their scientific outcomes. The results of scientific experiments and technology tests obtained with the MAIS will be used to improve future space based research. As the suspension force acting on the payload is very small, the MAIS can only be operative and tested in a weightless environment. The 'Deutsches Zentrum für Luft- und Raumfahrt e.V.' (DLR, German Aerospace Centre) granted a flight opportunity to the MAIS experiment to be tested during its 27th parabolic flight campaign of September 2015 performed on the A310 ZERO-G aircraft managed by the French company Novespace, a subsidiary of the 'Centre National d'Etudes Spatiales' (CNES, French Space Agency). The experiment results confirmed that the 6 degrees of freedom motion control technique was effective, and that the vibration isolation performance fulfilled perfectly the expectations based on theoretical analyses and simulations. This paper will present the design of the MAIS and the experiment results obtained during the

Adaptation of Mouse Skeletal Muscle to Long-Term Microgravity in the MDS Mission

Science.gov (United States)

Camerino, Giulia M.; Bianchini, Elisa; Ciciliot, Stefano; Danieli-Betto, Daniela; Dobrowolny, Gabriella; Furlan, Sandra; Germinario, Elena; Goto, Katsumasa; Gutsmann, Martina; Kawano, Fuminori; Nakai, Naoya; Ohira, Takashi; Ohno, Yoshitaka; Picard, Anne; Salanova, Michele; Schiffl, Gudrun; Blottner, Dieter; Musarò, Antonio; Ohira, Yoshinobu; Betto, Romeo; Conte, Diana; Schiaffino, Stefano

2012-01-01

The effect of microgravity on skeletal muscles has so far been examined in rat and mice only after short-term (5–20 day) spaceflights. The mice drawer system (MDS) program, sponsored by Italian Space Agency, for the first time aimed to investigate the consequences of long-term (91 days) exposure to microgravity in mice within the International Space Station. Muscle atrophy was present indistinctly in all fiber types of the slow-twitch soleus muscle, but was only slightly greater than that observed after 20 days of spaceflight. Myosin heavy chain analysis indicated a concomitant slow-to-fast transition of soleus. In addition, spaceflight induced translocation of sarcolemmal nitric oxide synthase-1 (NOS1) into the cytosol in soleus but not in the fast-twitch extensor digitorum longus (EDL) muscle. Most of the sarcolemmal ion channel subunits were up-regulated, more in soleus than EDL, whereas Ca2+-activated K+ channels were down-regulated, consistent with the phenotype transition. Gene expression of the atrophy-related ubiquitin-ligases was up-regulated in both spaceflown soleus and EDL muscles, whereas autophagy genes were in the control range. Muscle-specific IGF-1 and interleukin-6 were down-regulated in soleus but up-regulated in EDL. Also, various stress-related genes were up-regulated in spaceflown EDL, not in soleus. Altogether, these results suggest that EDL muscle may resist to microgravity-induced atrophy by activating compensatory and protective pathways. Our study shows the extended sensitivity of antigravity soleus muscle after prolonged exposition to microgravity, suggests possible mechanisms accounting for the resistance of EDL, and individuates some molecular targets for the development of countermeasures. PMID:22470446

Adaptation of mouse skeletal muscle to long-term microgravity in the MDS mission.

Directory of Open Access Journals (Sweden)

Dorianna Sandonà

Full Text Available The effect of microgravity on skeletal muscles has so far been examined in rat and mice only after short-term (5-20 day spaceflights. The mice drawer system (MDS program, sponsored by Italian Space Agency, for the first time aimed to investigate the consequences of long-term (91 days exposure to microgravity in mice within the International Space Station. Muscle atrophy was present indistinctly in all fiber types of the slow-twitch soleus muscle, but was only slightly greater than that observed after 20 days of spaceflight. Myosin heavy chain analysis indicated a concomitant slow-to-fast transition of soleus. In addition, spaceflight induced translocation of sarcolemmal nitric oxide synthase-1 (NOS1 into the cytosol in soleus but not in the fast-twitch extensor digitorum longus (EDL muscle. Most of the sarcolemmal ion channel subunits were up-regulated, more in soleus than EDL, whereas Ca(2+-activated K(+ channels were down-regulated, consistent with the phenotype transition. Gene expression of the atrophy-related ubiquitin-ligases was up-regulated in both spaceflown soleus and EDL muscles, whereas autophagy genes were in the control range. Muscle-specific IGF-1 and interleukin-6 were down-regulated in soleus but up-regulated in EDL. Also, various stress-related genes were up-regulated in spaceflown EDL, not in soleus. Altogether, these results suggest that EDL muscle may resist to microgravity-induced atrophy by activating compensatory and protective pathways. Our study shows the extended sensitivity of antigravity soleus muscle after prolonged exposition to microgravity, suggests possible mechanisms accounting for the resistance of EDL, and individuates some molecular targets for the development of countermeasures.

Facial Soft Tissue Measurement in Microgravity-induces Fluid Shifts

Science.gov (United States)

Marshburn, Thomas; Cole, Richard; Pavela, James; Garcia, Kathleen; Sargsyan, Ashot

2014-01-01

Fluid shifts are a well-known phenomenon in microgravity, and one result is facial edema. Objective measurement of tissue thickness in a standardized location could provide a correlate with the severity of the fluid shift. Previous studies of forehead tissue thickness (TTf) suggest that when exposed to environments that cause fluid shifts, including hypergravity, head-down tilt, and high-altitude/lowpressure, TTf changes in a consistent and measurable fashion. However, the technique in past studies is not well described or standardized. The International Space Station (ISS) houses an ultrasound (US) system capable of accurate sub-millimeter measurements of TTf. We undertook to measure TTf during long-duration space flight using a new accurate, repeatable and transferable technique. Methods: In-flight and post-flight B-mode ultrasound images of a single astronaut's facial soft tissues were obtained using a Vivid-q US system with a 12L-RS high-frequency linear array probe (General Electric, USA). Strictly mid-sagittal images were obtained involving the lower frontal bone, the nasofrontal angle, and the osseo-cartilaginous junction below. Single images were chosen for comparison that contained identical views of the bony landmarks and identical acoustical interface between the probe and skin. Using Gingko CADx DICOM viewing software, soft tissue thickness was measured at a right angle to the most prominent point of the inferior frontal bone to the epidermis. Four independent thickness measurements were made. Conclusions: Forehead tissue thickness measurement by ultrasound in microgravity is feasible, and our data suggest a decrease in tissue thickness upon return from microgravity environment, which is likely related to the cessation of fluid shifts. Further study is warranted to standardize the technique with regard to the individual variability of the local anatomy in this area.

A hydroponic system for microgravity plant experiments

Science.gov (United States)

Wright, B. D.; Bausch, W. C.; Knott, W. M.

1988-01-01

The construction of a permanently manned space station will provide the opportunity to grow plants for weeks or months in orbit for experiments or food production. With this opportunity comes the need for a method to provide plants with a continuous supply of water and nutrients in microgravity. The Capillary Effect Root Environment System (CERES) uses capillary forces to maintain control of circulating plant nutrient solution in the weightless environment of an orbiting spacecraft. The nutrient solution is maintained at a pressure slightly less than the ambient air pressure while it flows on one side of a porous membrane. The root, on the other side of the membrane, is surrounded by a thin film of nutrient solution where it contacts the moist surface of the membrane. The root is provided with water, nutrients and air simultaneously. Air bubbles in the nutrient solution are removed using a hydrophobic/hydrophilic membrane system. A model scaled to the size necessary for flight hardware to test CERES in the space shuttle was constructed.

Performance of droplet generator and droplet collector in liquid droplet radiator under microgravity

Science.gov (United States)

Totani, T.; Itami, M.; Nagata, H.; Kudo, I.; Iwasaki, A.; Hosokawa, S.

2002-06-01

The Liquid Droplet Radiator (LDR) has an advantage over comparable conventional radiators in terms of the rejected heat power-weight ratio. Therefore, the LDR has attracted attention as an advanced radiator for high-power space systems that will be prerequisite for large space structures. The performance of the LDR under microgravity condition has been studied from the viewpoint of operational space use of the LDR in the future. In this study, the performances of a droplet generator and a droplet collector in the LDR are investigated using drop shafts in Japan: MGLAB and JAMIC. As a result, it is considered that (1) the droplet generator can produce uniform droplet streams in the droplet diameter range from 200 to 280 [µm] and the spacing range from 400 to 950 [µm] under microgravity condition, (2) the droplet collector with the incidence angle of 35 degrees can prevent a uniform droplet stream, in which droplet diameter is 250 [µm] and the velocity is 16 [m/s], from splashing under microgravity condition, whereas splashes may occur at the surface of the droplet collector in the event that a nonuniform droplet stream collides against it.

Studies on the growth and indole-3-acetic acid and abscisic acid content of Zea mays seedlings grown in microgravity

Science.gov (United States)

Schulze, A.; Jensen, P. J.; Desrosiers, M.; Buta, J. G.; Bandurski, R. S.

1992-01-01

Measurements were made of the fresh weight, dry weight, dry weight-fresh weight ratio, free and conjugated indole-3-acetic acid, and free and conjugated abscisic acid in seedlings of Zea mays grown in darkness in microgravity and on earth. Imbibition of the dry kernels was 17 h prior to launch. Growth was for 5 d at ambient orbiter temperature and at a chronic accelerational force of the order of 3 x 10(-5) times earth gravity. Weights and hormone content of the microgravity seedlings were, with minor exceptions, not statistically different from seedlings grown in normal gravity. The tissues of the shuttle-grown plants appeared normal and the seedlings differed only in the lack of orientation of roots and shoots. These findings, based upon 5 d of growth in microgravity, cannot be extrapolated to growth in microgravity for weeks, months, and years, as might occur on a space station. Nonetheless, it is encouraging, for prospects of bioregeneration of the atmosphere and food production in a space station, that no pronounced differences in the parameters measured were apparent during the 5 d of plant seedling growth in microgravity.

The expression of heat shock proteins 70 and 90 in pea seedlings under simulated microgravity conditions

Science.gov (United States)

Kozeko, L.

Microgravity is an abnormal and so stress factor for plants. Expression of known stress-related genes is appeared to implicate in the cell response to different kinds of stress. Heat shock proteins HSP70 and HSP90 are present in plant cells under the normal growth conditions and their quantity increases during stress. The effect of simulated microgravity on expression of HSP70 and HSP90 was studied in etiolated Pisum sativum seedlings grown on the horizontal clinostat (2 rpm) from seed germination for 3 days. Seedlings were also subjected to two other types of stressors: vertical clinorotatoin (2 rpm) and 2 h temperature elevation (40°C). HSPs' level was measured by ELISA. The quantity of both HSPs increased more than in three times in the seedlings on the horizontal clinostat in comparison with the stationary 1 g control. Vertical clinorotation also increased HSPs' level but less at about 20% than horizontal one. These effects were comparable with the influence of temperature elevation. The data presented suggest that simulated microgravity upregulate HSP70 and HSP90 expression. The increased HSPs' level might evidence the important functional role of these proteins in plant adaptation to microgravity. We are currently investigating the contribution of constitutive or inducible forms of the HSPs in this stress response.

Resource Management in the Microgravity Science Division

Science.gov (United States)

Casselle, Justine

2004-01-01

In the Microgravity Science Division, the primary responsibilities of the Business Management Office are resource management and data collection. Resource management involves working with a budget to do a number of specific projects, while data collection involves collecting information such as the status of projects and workforce hours. This summer in the Business Management Office I assisted Margie Allen with resource planning and the implementation of specific microgravity projects. One of the main duties of a Project Control Specialists, such as my mentor, is to monitor and analyze project manager s financial plans. Project managers work from the bottom up to determine how much money their project will cost. They then set up a twelve month operating plan which shows when money will be spent. I assisted my mentor in checking for variances in her data against those of the project managers. In order to successfully check for those variances, we had to understand: where the project is including plans vs. actual performance, why it is in its present condition, and what the future impact will be based on known budgetary parameters. Our objective was to make sure that the plan, or estimated resources input, are a valid reflection of the actual cost. To help with my understanding of the process, over the course of my tenure I had to obtain skills in Microsoft Excel and Microsoft Access.

Microgravity computing codes. User's guide

Science.gov (United States)

1982-01-01

Codes used in microgravity experiments to compute fluid parameters and to obtain data graphically are introduced. The computer programs are stored on two diskettes, compatible with the floppy disk drives of the Apple 2. Two versions of both disks are available (DOS-2 and DOS-3). The codes are written in BASIC and are structured as interactive programs. Interaction takes place through the keyboard of any Apple 2-48K standard system with single floppy disk drive. The programs are protected against wrong commands given by the operator. The programs are described step by step in the same order as the instructions displayed on the monitor. Most of these instructions are shown, with samples of computation and of graphics.

Effect of microgravity simulation using 3D clinostat on cavendish banana (Musa acuminata AAA Group) ripening process

Science.gov (United States)

Dwivany, Fenny Martha; Esyanti, Rizkita R.; Prapaisie, Adeline; Puspa Kirana, Listya; Latief, Chunaeni; Ginaldi, Ari

2016-11-01

The objective of the research was to determine the effect of microgravity simulation by 3D clinostat on Cavendish banana (Musa acuminata AAA group) ripening process. In this study, physical, physiological changes as well as genes expression were analysed. The result showed that in microgravity simulation condition ripening process in banana was delayed and the MaACOl, MaACSl and MaACS5 gene expression were affected.

Generating a picokelvin ultracold atomic ensemble in microgravity

International Nuclear Information System (INIS)

Wang, Lu; Ma, Zhao-Yuan; Zhang, Peng; Chen, Xu-Zong

2013-01-01

Applying the direct Monte Carlo simulation (DSMC) method developed for a cold atom system, we study the evaporative cooling process in tilted optical dipole traps with a magnetic field gradient-induced over-levitation or merely a gravitational force. We propose a two-stage decomposed evaporative cooling process in a microgravity environment, and suggest that quantum degeneracy can be obtained at a few picokelvins with several thousand atoms. (paper)

Increased efficiency of mammalian somatic cell hybrid production under microgravity conditions during ballistic rocket flight

Science.gov (United States)

Schnettler, R.; Gessner, P.; Zimmermann, U.; Neil, G. A.; Urnovitz, H. B.

1989-01-01

The electrofusion of hybridoma cell lines under short-duration microgravity during a flight of the TEXUS 18 Black Brand ballistic sounding rocket at Kiruna, Sweden is reported. The fusion partners, growth medium, cell fusion medium, cell fusion, cell viability in the fusion medium, and postfusion cell culture are described, and the rocket, cell fusion chamber, apparatus, and module are examined. The experimental timeline, the effects of fusion medium and incubation time on cell viability and hybrid yields, and the effect of microgravity on hybrid yields are considered.

Dewetting and Segregation of Zn-Doped InSb in Microgravity Experiments

Science.gov (United States)

Ostrogorsky, A. G.; Marin, C.; Duffar, T.; Volz, M.

2009-01-01

In directional solidification, dewetting is characterized by the lack of contact between the crystal and the crucible walls, due to the existence of a liquid meniscus at the level of the solid-liquid interface. This creates a gap of a few tens of micrometers between the crystal and the crucible. One of the immediate consequences of this phenomenon is the dramatic improvement of the quality of the crystal. This improvement is partly due to the modification of the solid-liquid interface curvature and partly to the absence of sticking and spurious nucleation at the crystal-crucible interface. Dewetting has been, commonly observed during the growth of semiconductors in crucibles under microgravity conditions where it appears to be very stable: the gap between the crystal and the crucible remains constant along several centimetres of growth. The physical models of the phenomenon are well established and they predict that dewetting should not occur in microgravity, if sufficient static pressure is imposed on the melt, pushing it towards the crucible. We present the results of InSb(Zn) solidification experiments conducted at the International Space Station (ISS) where, in spite of a spring exerting a pressure on the liquid, partial dewetting did occur. This surprising result is discussed in terms of force exerted .by the spring on the liquid and of possibility that the spring did not work properly. Furthermore, it appears that the segregation of the Zn was not affected by the occurrence of the dewetting. The data suggest that there was no significant interference of convection with segregation of Zn in InSb.

Quantitative EEG and its Correlation with Cardiovascular, Cognition and mood State: an Integrated Study in Simulated Microgravity

Science.gov (United States)

Zhang, Jianyuan; Hu, Bin; Chen, Wenjuan; Moore, Philip; Xu, Tingting; Dong, Qunxi; Liu, Zhenyu; Luo, Yuejia; Chen, Shanguang

2014-12-01

The focus of the study is the estimation of the effects of microgravity on the central nervous activity and its underlying influencing mechanisms. To validate the microgravity-induced physiological and psychological effects on EEG, quantitative EEG features, cardiovascular indicators, mood state, and cognitive performances data collection was achieved during a 45 day period using a -6°head-down bed rest (HDBR) integrated approach. The results demonstrated significant differences in EEG data, as an increased Theta wave, a decreased Beta wave and a reduced complexity of brain, accompanied with an increased heart rate and pulse rate, decreased positive emotion, and degraded emotion conflict monitoring performance. The canonical correlation analysis (CCA) based cardiovascular and cognitive related EEG model showed the cardiovascular effect on EEG mainly affected bilateral temporal region and the cognitive effect impacted parietal-occipital and frontal regions. The results obtained in the study support the use of an approach which combines a multi-factor influential mechanism hypothesis. The changes in the EEG data may be influenced by both cardiovascular and cognitive effects.

Microgravity Processing and Photonic Applications of Organic and Polymeric Materials

Science.gov (United States)

Frazier, Donald O.; Paley, Mark S.; Penn, Benjamin G.; Abdeldayem, Hossin A.; Smith, David D.; Witherow, William K.

1997-01-01

Some of the primary purposes of this work are to study important technologies, particularly involving thin films, relevant to organic and polymeric materials for improving applicability to optical circuitry and devices and to assess the contribution of convection on film quality in unit and microgravity environments. Among the most important materials processing techniques of interest in this work are solution-based and by physical vapor transport, both having proven gravitational and acceleration dependence. In particular, PolyDiAcetylenes (PDA's) and PhthaloCyanines (Pc's) are excellent NonLinear Optical (NLO) materials with the promise of significantly improved NLO properties through order and film quality enhancements possible through microgravity processing. Our approach is to focus research on integrated optical circuits and optoelectronic devices relevant to solution-based and vapor processes of interest in the Space Sciences Laboratory at the Marshall Space Flight Center (MSFC). Modification of organic materials is an important aspect of achieving more highly ordered structures in conjunction with microgravity processing. Parallel activities include characterization of materials for particular NLO properties and determination of appropriation device designs consistent with selected applications. One result of this work is the determination, theoretically, that buoyancy-driven convection occurs at low pressures in an ideal gas in a thermalgradient from source to sink. Subsequent experiment supports the theory. We have also determined theoretically that buoyancy-driven convection occurs during photodeposition of PDA, an MSFC-patented process for fabricating complex circuits, which is also supported by experiment. Finally, the discovery of intrinsic optical bistability in metal-free Pc films enables the possibility of the development of logic gate technology on the basis of these materials.

The pituitary-testicular axis in microgravity: analogies with the aging male syndrome.

Science.gov (United States)

Strollo, F; Boitani, C; Basciani, S; Pecorelli, L; Palumbo, D; Borgia, L; Masini, M A; Morè, M; Strollo, G; Spera, G; Uva, B M; Riondino, G

2005-01-01

Extraterrestrial exploration has gone on for decades before reversible testicular failure was shown to be a consequence of space flight in humans and animals at the end of the XXth century. This phenomenon was initially thought to depend on the psycho-physical stress expected to derive from a decidedly unusual environment, but the lack of consistent data concerning cortisol increase and/or gonadotrophin suppression pointed to the possibility of a primary defect. This was indirectly confirmed by the observation that a continuum of testicular androgen secretion potential exists from microgravity to centrifuge-derived hypergravity. Further experiments using tissue slices and suspended cells confirmed a direct inhibitory effect of microgravity upon testicular androgen production. A parallel deterioration of major physiological parameters, such as bone density, muscle mass/force, red blood cell mass, hydration and cardiopulmonary performance, has been repeatedly described during space missions, which, luckily enough, fully recover within days to weeks after landing, the time lag depending on single organ/system adaptation rates. According to the Authors of the present review, when taking together all reported changes occurring in space, a picture emerges closely resembling the so-called aging male syndrome, which is currently the object of daily screening and clinical care in their endocrine unit, so that microgravity may become a tool for better understanding subtle mechanisms of testicular senescence.

The organization of the fuc regulon specifying L-fucose dissimilation in Escherichia coli K12 as determined by gene cloning.

Science.gov (United States)

Chen, Y M; Zhu, Y; Lin, E C

1987-12-01

In Escherichia coli the six known genes specifying the utilization of L-fucose as carbon and energy source cluster at 60.2 min and constitute a regulon. These genes include fucP (encoding L-fucose permease), fucI (encoding L-fucose isomerase), fucK (encoding L-fuculose kinase), fucA (encoding L-fuculose 1-phosphate aldolase), fucO (encoding L-1,2-propanediol oxidoreductase), and fucR (encoding the regulatory protein). In this study the fuc genes were cloned and their positions on the chromosome were established by restriction endonuclease and complementation analyses. Clockwise, the gene order is: fucO-fucA-fucP-fucI-fucK-fucR. The operons comprising the structural genes and the direction of transcription were determined by complementation analysis and Southern blot hybridization. The fucPIK and fucA operons are transcribed clockwise. The fucO operon is transcribed counterclockwise. The fucR gene product activates the three structural operons in trans.

Particle Engulfment and Pushing (PEP): Past Micro-Gravity Experiments and Future Experimental Plan on the International Space Station (ISS)

Science.gov (United States)

Sen, Subhayu; Stefanescu, Doru M.; Catalina, A. V.; Juretzko, F.; Dhindaw, B. K.; Curreri, P. A.; Whitaker, Ann F. (Technical Monitor)

2001-01-01

The interaction of an insoluble particle with a growing solid-liquid interface (SLI) has been a subject of investigation for the four decades. For a metallurgist or a material scientist understanding the fundamental physics of such an interaction is relevant for applications that include distribution of reinforcement particles in metal matrix composites, inclusion management in castings, and distribution of Y2Ba1Cu1O5 (211) precipitates (flux pinning sites) in Y1Ba2Cu3O7 (123) superconducting crystals. The same physics is also applicable to other areas including geological applications (frost heaving in soils) and preservation of biological cells. Experimentally this interaction can be quantified in terms of a critical growth velocity, Vcr, of the SLI below which particles are pushed ahead of the advancing interface, and above which the particles are engulfed. Past experimental evidence suggests that this Vcr is an inverse function of the particle radius, R. In order to isolate the fundamental physics that governs such a relationship it is necessary to minimize natural convection at the SLI that is inherent in ground based experiments. Hence for the purpose of producing benchmark data (Vcr vs. R) PEP is a natural candidate for micro-gravity experimentation. Accordingly, experiments with pure Al containing a dispersion of ZrO2 particles and an organic analogue, succinonitrile (SCN) containing polystyrene particles have been performed on the LMS and USMP-4 mission respectively. In this paper we will summarize the experimental data that was obtained during these two micro-gravity missions and show that the results differ compared to terrestrial experiments. We will also discuss the basic elements of our analytical and numerical model and present a comparison of the predictions of these models against micro-gravity experimental data. Finally. we will discuss our future experimental plan that includes the ISS glovebox and MSRRl.

Induction of hypoxic root metabolism results from physical limitations in O2 bioavailability in microgravity.

Science.gov (United States)

Liao, J; Liu, G; Monje, O; Stutte, G W; Porterfield, D M

2004-01-01

activities, while the control and clinostat treatments showed no response. This work demonstrates: (1) the inhibition of gravity-driven convective transport can reduce the O2 bioavailability to the root tip, and (2) the perturbation of gravisensing by clinostat rotation does not induce a nonspecific stress response involving ADH. Together these experiments support the microgravity convection inhibition model for explaining changes in root metabolism during spaceflight. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

Theoretical analysis of the particle properties and polarization measurements made in microgravity

CERN Document Server

Penttilae, A; Worms, J C; Hadamcik, E; Renard, J B; Levasseur-Regourd, A C

2003-01-01

We propose a new model to describe the shapes of stochastic polyhedra used in the microgravity experiment PROGRA sup 2 on board the Airbus A300 aircraft. The polarization measurements of scattering of visible light by boron carbide (B sub 4 C) particles with sizes between 9 and 88 mu m can nicely be explained with the derived shape statistics and the (currently unknown) refractive index obtained. For the latter we derive 2 (-0.15/+0.1)+0.04i(-0.0025/+0.015) at 632.8 nm wavelength. The polarization method is a reliable and sensitive means to estimate various particle properties in various remote sensing applications, including the planetary sciences.

Microgravity Science Glovebox Aboard the International Space Station

Science.gov (United States)

2003-01-01

In the Destiny laboratory aboard the International Space Station (ISS), European Space Agency (ESA) astronaut Pedro Duque of Spain is seen working at the Microgravity Science Glovebox (MSG). He is working with the PROMISS experiment, which will investigate the growth processes of proteins during weightless conditions. The PROMISS is one of the Cervantes program of tests (consisting of 20 commercial experiments). The MSG is managed by NASA's Marshall Space Flight Center (MSFC).

Transcutaneous Noninvasive Device for the Responsive Delivery of Melatonin in Microgravity., Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Our goal is develop a smart, transcutaneous device for individualized circadian (sleep) therapy by responsive release of melatonin, in microgravity. Additionally,...

Planar air-bearing microgravity simulators: Review of applications, existing solutions and design parameters

Science.gov (United States)

Rybus, Tomasz; Seweryn, Karol

2016-03-01

All devices designed to be used in space must be thoroughly tested in relevant conditions. For several classes of devices the reduced gravity conditions are the key factor. In early stages of development and later due to financial reasons, the tests need to be done on Earth. However, in Earth conditions it is impossible to obtain a different gravity field independent on all linear and rotational spatial coordinates. Therefore, various test-bed systems are used, with their design driven by the device's specific needs. One of such test-beds are planar air-bearing microgravity simulators. In such an approach, the tested objects (e.g., manipulators intended for on-orbit operations or vehicles simulating satellites in a close formation flight) are mounted on planar air-bearings that allow almost frictionless motion on a flat surface, thus simulating microgravity conditions in two dimensions. In this paper we present a comprehensive review of research activities related to planar air-bearing microgravity simulators, demonstrating achievements of the most active research groups and describing newest trends and ideas, such as tests of landing gears for low-g bodies. Major design parameters of air-bearing test-beds are also reviewed and a list of notable existing test-beds is presented.

Macrosegregation During Re-melting and Holding of Directionally Solidified Al-7 wt.% Si Alloy in Microgravity

Science.gov (United States)

Lauer, M.; Ghods, M.; Angart, S. G.; Grugel, R. N.; Tewari, S. N.; Poirier, D. R.

2017-08-01

As-cast aluminum-7 wt.% ailicon alloy sample rods were re-melted and directionally solidified on Earth which resulted in uniform dendritically aligned arrays. These arrays were then partially back-melted through an imposed, and constant, temperature gradient in the microgravity environment aboard the International Space Station. The mushy zones that developed in the seed crystals were held for different periods prior to initiating directional solidification. Upon return, examination of the initial mushy-zone regions exhibited significant macrosegregation in terms of a solute-depleted zone that increased as a function of the holding time. The silicon (solute) content in these regions was measured on prepared longitudinal sections by electron microprobe analysis as well as by determining the fraction eutectic on several transverse sections. The silicon content was found to increase up the temperature gradient resulting in significant silicon concentration immediately ahead of the mushy-zone tips. The measured macrosegregation agrees well with calculations from a mathematical model developed to simulate the re-melting and holding process. The results, due to processing in a microgravity environment where buoyancy and thermosolutal convection are minimized, serve as benchmark solidification data.

Effects of pseudo-microgravity on symbiosis between endophyte, Neotyphodium, and its host plant, tall fescue (Festuca arundinacea)

Science.gov (United States)

Tomita-Yokotani, K.; Wakabayashi, K.; Hiraishi, K.; Yoshida, S.; Hashimoto, H.; Shinozaki, S.; Yamashita, M.

Endophyte is a group of microbes that symbiotically live in plant body Endophyte provides host plant its metabolites that protect the plant from insect pests In addition to this host plants are resistive against environmental stress In general endophyte lives in seeds to seeds of the infected plants through multiple generations The infection of fungi has never been observed and their original pathway is still unknown in nature The aim of this study is to examine whether this stable symbiosis between endophytes and its host plant would be modified under pseudo-microgravity or not We also aim to observe the infection under an exotic environment in terms of gravity We found that the internal hyphae of both the incubated plant under pseudo-microgravity and the ground control became indistinct with the number of incubation days A part of the endophyte in the seed under its autolysis was suggested because the amount of fungi in the base of the shoot that was observed with the incubated plant under the ground control was far less than that in the seed before sowing Hyphae began to grow in the germinating seed after a 3-day incubation period However a lot of aggregated fungi still existed in the 3-day incubated seed under pseudo-microgravity Moreover hyphae in the 3-day incubated seed under pseudo-microgravity were more indistinctly than that under the ground control The fungi were observed in the boundary of the seed and the shoot of the 5-day incubated seed under the ground control but not under pseudo-microgravity By this observation it was suggested that

Compact field color schlieren system for use in microgravity materials processing

Science.gov (United States)

Poteet, W. M.; Owen, R. B.

1986-01-01

A compact color schlieren system designed for field measurement of materials processing parameters has been built and tested in a microgravity environment. Improvements in the color filter design and a compact optical arrangement allowed the system described here to retain the traditional advantages of schlieren, such as simplicity, sensitivity, and ease of data interpretation. Testing was accomplished by successfully flying the instrument on a series of parabolic trajectories on the NASA KC-135 microgravity simulation aircraft. A variety of samples of interest in materials processing were examined. Although the present system was designed for aircraft use, the technique is well suited to space flight experimentation. A major goal of this effort was to accommodate the main optical system within a volume approximately equal to that of a Space Shuttle middeck locker. Future plans include the development of an automated space-qualified facility for use on the Shuttle and Space Station.

Study on the creation of biopolymer materials under micro-gravity; Bisho juryokuka deno seitai kobunshi zairyo no sosei kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

In order to create new functional organic thin film materials, basic data were examined under micro-gravity. Polymerization of pyrrole was affected by micro-gravity after a few minutes from the beginning of reaction. Although relatively uniform particles were obtained, the particle size was finely dependent on conditions. Electrolytic polymerization of conductive organic thin films was yet unstable in reproducibility. On orientation control and thin film formation of protein under gravity-free environment, electrodeposited films were obtained using bacteriorhodopsin film suspension by applying voltage of 6.4V for 9s after 1s from falling. The reproducibility of the number and area of molecular layers was poor. On the study on the formation process of organic thin films, creation of homogeneous films is probably possible by filtration from suspension under reduced pressure under micro-gravity for a short time. Trial linear polymer tied in a row was obtained by capillary injection of dense polymer solution. The viscous fingering phenomenon of viscoelastic bodies under micro-gravity was compared with that on the ground. 11 refs., 36 figs., 1 tab.

Does vector-free gravity simulate microgravity? Functional and morphologic attributes of clinorotated nerve and muscle grown in cell culture

Science.gov (United States)

Gruener, R.; Hoeger, G.

1988-01-01

Cocultured Xenopus neurons and myocytes were subjected to non-vectorial gravity by clinostat rotation to determine if microgravity, during space flights, may affect cell development and communications. Clinorotated cells showed changes consistent with the hypothesis that cell differentiation, in microgravity, is altered by interference with cytoskeleton-related mechanisms. We found: increases in the myocyte and its nuclear area, "fragmentation" of nucleoli, appearance of neuritic "aneurysms", decreased growth in the presence of "trophic" factors, and decreased yolk utilization. The effects were most notable at 1-10 rpm and depended on the onset and duration of rotation. Some parameters returned to near control values within 48 hrs after cessation of rotation. Cells from cultures rotated at higher speeds (>50 rpm) appeared comparable to controls. Compensation by centrifugal forces may account for this finding. Our data are consistent, in principle, with effects on other, flighted cells and suggest that "vector-free" gravity may simulate certain aspects of microgravity. The distribution of acetylcholine receptor aggregates, on myocytes, was also altered. This indicates that brain development, in microgravity, may also be affected.

Pressure-volume-temperature gauging method experiment using liquid nitrogen under microgravity condition of parabolic flight

Energy Technology Data Exchange (ETDEWEB)

Seo, Man Su; Park, Hana; Yoo, Don Gyu; Jeong, Sang Kwon [Cryogenic Engineering Laboratory, Department of Mechanical Engineering, KAIST, Daejeon (Korea, Republic of); Jung, Young Suk [Launcher Systems Development Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of)

2014-06-15

Measuring an exact amount of remaining cryogenic liquid propellant under microgravity condition is one of the important issues of rocket vehicle. A Pressure-Volume-Temperature (PVT) gauging method is attractive due to its minimal additional hardware and simple gauging process. In this paper, PVT gauging method using liquid nitrogen is investigated under microgravity condition with parabolic flight. A 9.2 litre metal cryogenic liquid storage tank containing approximately 30% of liquid nitrogen is pressurized by ambient temperature helium gas. During microgravity condition, the inside of the liquid tank becomes near-isothermal condition within 1 K difference indicated by 6 silicon diode sensors vertically distributed in the middle of the liquid tank. Helium injection with higher mass flow rate after 10 seconds of the waiting time results in successful measurements of helium partial pressure in the tank. Average liquid volume measurement error is within 11% of the whole liquid tank volume and standard deviation of errors is 11.9. As a result, the applicability of PVT gauging method to liquid.

Pressure-volume-temperature gauging method experiment using liquid nitrogen under microgravity condition of parabolic flight

International Nuclear Information System (INIS)

Seo, Man Su; Park, Hana; Yoo, Don Gyu; Jeong, Sang Kwon; Jung, Young Suk

2014-01-01

Measuring an exact amount of remaining cryogenic liquid propellant under microgravity condition is one of the important issues of rocket vehicle. A Pressure-Volume-Temperature (PVT) gauging method is attractive due to its minimal additional hardware and simple gauging process. In this paper, PVT gauging method using liquid nitrogen is investigated under microgravity condition with parabolic flight. A 9.2 litre metal cryogenic liquid storage tank containing approximately 30% of liquid nitrogen is pressurized by ambient temperature helium gas. During microgravity condition, the inside of the liquid tank becomes near-isothermal condition within 1 K difference indicated by 6 silicon diode sensors vertically distributed in the middle of the liquid tank. Helium injection with higher mass flow rate after 10 seconds of the waiting time results in successful measurements of helium partial pressure in the tank. Average liquid volume measurement error is within 11% of the whole liquid tank volume and standard deviation of errors is 11.9. As a result, the applicability of PVT gauging method to liquid

Ultrastructural changes in osteocytes in microgravity conditions

Science.gov (United States)

Rodionova, N. V.; Oganov, V. S.; Zolotova, N. V.

We examined the histology and morphometry of biosamples (biopsies) of the iliac crest of monkeys, flown 14 days aboard the "Bion-11", using electron microscopy. We found, that some young osteocytes take part in the activization of collagen protein biosynthesis in the adaptive remodeling process of the bone tissue to microgravity conditions. Osteocyte lacunae filled with collagen fibrils; this correlates with fibrotic osteoblast reorganization in such zones. The osteolytic activity in mature osteocytes is intensified. As a result of osteocyte destruction, the quantity of empty osteocytic lacunae in the bone tissue increases.

The performance test of a modified miniature rotary compressor in upright and inverted modes subjected to microgravity

International Nuclear Information System (INIS)

Ma, Rui; Wu, Yu-ting; Du, Chun-xu; Chen, Xia; Zhang, De-lou; Ma, Chong-fang

2016-01-01

Highlights: • A miniature rotary compressor by ASPEN company was modified. • The modified compressor can be employed in microgravity. • Performance of upright compressor is superior to inverted mode in most cases. • Performance curves of system with inverted compressor are obtained. • Experimental results of compressor inverted and upright are compared. - Abstract: Vapor compression heat pump is a new concept of thermal control system and refrigerator for future space use. Compressor is a key component in the vapor compression heat pump. Development of compressor capable of operating in both microgravity (10 E-6 g) and lunar (1/6 g) environments is urgently needed for space thermal control systems based on heat pump technique. In this paper, a miniature rotary compressor by ASPEN company was modified to realize acceptable compressor lubrication and oil circulation in microgravity environments. An experimental system was built up to check the performance of the modified compressor subjected to microgravity. A performances comparison of inverted compressor with upright one was made. The influences of operating parameters such as refrigerant charge, cooling water temperature as well as compressor speed on the performances of vapor compression heat pump were investigated. The results show that the modified miniature rotary compressor in inverted mode can operate stably in a long period, which indicates that the modified compressor can be employed in microgravity environments. Compressor discharge temperature increased or decreased while COP changed more obviously with cooling water temperature and speed in microgravity. In most cases, performance of the upright compressor is superior to that of the inverted one. But when the compressor speed is from 1500 rpm to 2500 rpm or the coolant temperature is between 20 and 25 degrees, the performance of inverted compressor is better. The highest discharge temperature of the inverted compressor can be as high

Phototropism experiments in microgravity-the Seedling Growth project in the EMCS on the ISS

Science.gov (United States)

Kiss, John; Edelmann, Richard; Herranz, Raul; Medina, Francisco Javier; Millar, Katherine

The microgravity environment aboard orbiting spacecraft has provided a unique laboratory to explore important topics in basic plant biology. Our group has utilized the European Modular Cultivation System (EMCS) aboard the International Space Station (ISS) to study plant growth, development, tropisms, and gene expression in a series of spaceflight experiments. The most current project performed on the ISS was termed Seeding Growth-1 (SG-1) which builds on the previous TROPI (for tropisms) experiments. TROPI-1 was the first EMCS experiment, and we discovered a novel red-light-based phototropism in hypocotyls of seedlings grown in microgravity (Millar et al. 2010). In TROPI-2, our experiments were extended to reduced gravity levels and found that 0.1-0.3 g can attenuate the red-light response (Kiss et al. 2012). In addition, we performed gene profiling studies and noted that approximately 280 genes that were differentially regulated at least two-fold in the space samples compared to the ground controls (Correll et al. 2013). Major technical and operational changes in SG-1 (launched in March 2013) compared to the TROPI experiments include: improvements in lighting conditions within the EMCS to optimize the environment for phototropism studies and the use of infrared illumination to provide high-quality images of the seedlings. In SG-1, the red-light-based phototropism in roots and hypocotyls of seedlings that was noted in TROPI-2 was confirmed and now can be more precisely characterized based on the improvements in procedures. As we move forward, the SG-2 experiments (to be launched in 2014), in addition to a continued focus on phototropism, will consider the cell cycle as well as the growth and proliferation of plant cells in microgravity (Matía et al. 2010). Furthermore, the lessons learned from sequential experiments from TROPI-1 to TROPI-2 to SG-1 can provide insights to other researchers developing space experiments in plant biology. References: Correll M.J., T

Strata-1: An International Space Station Experiment into Fundamental Regolith Processes in Microgravity

Science.gov (United States)

Fries, M.; Abell, P.; Brisset, J.; Britt, D.; Colwell, J.; Durda, D.; Dove, A.; Graham, L.; Hartzell, C.; John, K.;

The Vibrio cholerae var regulon encodes a metallo-β-lactamase and an antibiotic efflux pump, which are regulated by VarR, a LysR-type transcription factor.

Directory of Open Access Journals (Sweden)

Hong-Ting Victor Lin

Full Text Available The genome sequence of V. cholerae O1 Biovar Eltor strain N16961 has revealed a putative antibiotic resistance (var regulon that is predicted to encode a transcriptional activator (VarR, which is divergently transcribed relative to the putative resistance genes for both a metallo-β-lactamase (VarG and an antibiotic efflux-pump (VarABCDEF. We sought to test whether these genes could confer antibiotic resistance and are organised as a regulon under the control of VarR. VarG was overexpressed and purified and shown to have β-lactamase activity against penicillins, cephalosporins and carbapenems, having the highest activity against meropenem. The expression of VarABCDEF in the Escherichia coli (ΔacrAB strain KAM3 conferred resistance to a range of drugs, but most significant resistance was to the macrolide spiramycin. A gel-shift analysis was used to determine if VarR bound to the promoter regions of the resistance genes. Consistent with the regulation of these resistance genes, VarR binds to three distinct intergenic regions, varRG, varGA and varBC located upstream and adjacent to varG, varA and varC, respectively. VarR can act as a repressor at the varRG promoter region; whilst this repression was relieved upon addition of β-lactams, these did not dissociate the VarR/varRG-DNA complex, indicating that the de-repression of varR by β-lactams is indirect. Considering that the genomic arrangement of VarR-VarG is strikingly similar to that of AmpR-AmpC system, it is possible that V. cholerae has evolved a system for resistance to the newer β-lactams that would prove more beneficial to the bacterium in light of current selective pressures.

Increased sensitivity of DNA damage response-deficient cells to stimulated microgravity-induced DNA lesions.

Directory of Open Access Journals (Sweden)

Nan Li

Full Text Available Microgravity is a major stress factor that astronauts have to face in space. In the past, the effects of microgravity on genomic DNA damage were studied, and it seems that the effect on genomic DNA depends on cell types and the length of exposure time to microgravity or simulated microgravity (SMG. In this study we used mouse embryonic stem (MES and mouse embryonic fibroblast (MEF cells to assess the effects of SMG on DNA lesions. To acquire the insight into potential mechanisms by which cells resist and/or adapt to SMG, we also included Rad9-deleted MES and Mdc1-deleted MEF cells in addition to wild type cells in this study. We observed significant SMG-induced DNA double strand breaks (DSBs in Rad9-/- MES and Mdc1-/- MEF cells but not in their corresponding wild type cells. A similar pattern of DNA single strand break or modifications was also observed in Rad9-/- MES. As the exposure to SMG was prolonged, Rad9-/- MES cells adapted to the SMG disturbance by reducing the induced DNA lesions. The induced DNA lesions in Rad9-/- MES were due to SMG-induced reactive oxygen species (ROS. Interestingly, Mdc1-/- MEF cells were only partially adapted to the SMG disturbance. That is, the induced DNA lesions were reduced over time, but did not return to the control level while ROS returned to a control level. In addition, ROS was only partially responsible for the induced DNA lesions in Mdc1-/- MEF cells. Taken together, these data suggest that SMG is a weak genomic DNA stress and can aggravate genomic instability in cells with DNA damage response (DDR defects.

Space headache on Earth: head-down-tilted bed rest studies simulating outer-space microgravity.

Science.gov (United States)

van Oosterhout, W P J; Terwindt, G M; Vein, A A; Ferrari, M D

2015-04-01

Headache is a common symptom during space travel, both isolated and as part of space motion syndrome. Head-down-tilted bed rest (HDTBR) studies are used to simulate outer space microgravity on Earth, and allow countermeasure interventions such as artificial gravity and training protocols, aimed at restoring microgravity-induced physiological changes. The objectives of this article are to assess headache incidence and characteristics during HDTBR, and to evaluate the effects of countermeasures. In a randomized cross-over design by the European Space Agency (ESA), 22 healthy male subjects, without primary headache history, underwent three periods of -6-degree HDTBR. In two of these episodes countermeasure protocols were added, with either centrifugation or aerobic exercise training protocols. Headache occurrence and characteristics were daily assessed using a specially designed questionnaire. In total 14/22 (63.6%) subjects reported a headache during ≥1 of the three HDTBR periods, in 12/14 (85.7%) non-specific, and two of 14 (14.4%) migraine. The occurrence of headache did not differ between HDTBR with and without countermeasures: 12/22 (54.5%) subjects vs. eight of 22 (36.4%) subjects; p = 0.20; 13/109 (11.9%) headache days vs. 36/213 (16.9%) headache days; p = 0.24). During countermeasures headaches were, however, more often mild (p = 0.03) and had fewer associated symptoms (p = 0.008). Simulated microgravity during HDTBR induces headache episodes, mostly on the first day. Countermeasures are useful in reducing headache severity and associated symptoms. Reversible, microgravity-induced cephalic fluid shift may cause headache, also on Earth. HDTBR can be used to study space headache on Earth. © International Headache Society 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Microgravity Outreach with Math Teachers

Science.gov (United States)

2000-01-01

Don Gillies, a materials scientist at NASA/Marshall Space Flight Center (MSFC), demonstrates the greater bounce to the ounce of metal made from a supercooled bulk metallic glass alloy that NASA is studying in space experiments. The metal plates at the bottom of the plexiglass tubes are made of three different types of metal. Bulk metallic glass is more resilient and, as a result, the dropped ball bearing bounces higher. Fundamental properties of this bulk metallic glass were measured in a space flight in 1997 Microgravity Science Laboratory-1 (MSL-1) mission. These properties could not have been measured on Earth and have been incorporated into recent design. This demonstration was at the April 2000 conference of the National Council of Teachers of Mathematics (NCTM) in Chicago. Photo credit: NASA/Marshall Space Flight Center (MSFC)

Integration of micro-gravity and geodetic data to constrain shallow system mass changes at Krafla Volcano, N Iceland

Science.gov (United States)

de Zeeuw-van Dalfsen, Elske; Rymer, Hazel; Williams-Jones, Glyn; Sturkell, Erik; Sigmundsson, Freysteinn

2006-04-01

New and previously published micro-gravity data are combined with InSAR data, precise levelling and GPS measurements to produce a model for the processes operating at Krafla volcano, 20 years after its most recent eruption. The data have been divided into two periods: from 1990 to 1995 and from 1996 to 2003 and show that the rate of deflation at Krafla is decaying exponentially. The net micro-gravity change at the centre of the caldera is shown, using the measured free air gradient, to be -85 μGal for the first and -100 μGal for the second period. After consideration of the effects of water extraction by the geothermal power station within the caldera, the net gravity decreases are -73±17 μGal for the first and -65±17 μGal for the second period. These decreases are interpreted in terms of magma drainage. Following a Mogi point source model, we calculate the mass decrease to be ˜2×1010 kg/year reflecting a drainage rate of ˜0.23 m3/s, similar to the ˜0.13 m3/s drainage rate previously found at Askja volcano, N. Iceland. Based on the evidence for deeper magma reservoirs and the similarity between the two volcanic systems, we suggest a pressure-link between Askja and Krafla at deeper levels (at the lower crust or the crust-mantle boundary). After the Krafla fires, co-rifting pressure decrease of a deep source at Krafla stimulated the subsequent inflow of magma, eventually affecting conditions along the plate boundary in N. Iceland, as far away as Askja. We anticipate that the pressure of the deeper reservoir at Krafla will reach a critical value and eventually magma will rise from there to the shallow magma chamber, possibly initiating a new rifting episode. We have demonstrated that by examining micro-gravity and geodetic data, our knowledge of active volcanic systems can be significantly improved.

Study on the effect of micro-gravity on bio-functions; Seitai kino eno bisho juryoku no eikyo ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The effect of micro-gravity on bio-functions and vital reaction was studied using the facility of Underground Gravity-free Experiment Center Co. On the effect on osteoblast shape and gene expression, although fluorochrome reacting with Ca was well taken into cells, no significant difference in Ca content in cells was observed before/after falling. Expression of genes related to cell propagation was controlled under micro-gravity. Protoplast fusion of Lentinus was unaffected by micro-gravity. The mRNA fragments of gravity sensitive mutant of rice plant were affected by micro-gravity. Paramecium was set swimming in solutions with different specific gravities. The reaction behavior of Paramecium was affected by the difference in specific gravity between cell bodies and solutions. The water content metabolism functions of a mouse with needle stimulus, in particular excretory, were slightly promoted by micro- gravity. The cortisol level in blood of a falling mouse group rose showing strong stress. As the preliminary study on the geotaxis of insects, motion of bagworm was observed. 12 refs., 38 figs., 4 tabs.

Experimental study on line-of-sight (LOS) attitude control using control moment gyros under micro-gravity environment

Science.gov (United States)

Kojima, Hirohisa; Hiraiwa, Kana; Yoshimura, Yasuhiro

2018-02-01

This paper presents the results of line-of-sight (LOS) attitude control using control moment gyros under a micro-gravity environment generated by parabolic flight. The W-Z parameters are used to describe the spacecraft attitude. In order to stabilize the current LOS to the target LOS, backstepping-based feedback control is considered using the W-Z parameters. Numerical simulations and experiments under a micro-gravity environment are carried out, and their results are compared in order to validate the proposed control methods.

Benefits of microgravity for measurement of thermo-transport coefficients in liquid metal alloys

International Nuclear Information System (INIS)

Praizey, J.P.

1988-05-01

After giving a brief review of thermo-transport principles, this paper describes the experimental technique used and presents the results obtained on the ground. The author determines the solutal stability conditions to be satisfied by the metal alloy so that ground thermotransport measurements are not disturbed by convection effects. The benefits of microgravity when such conditions cannot be achieved are demonstrated and the results obtained on pure Sn (isotope separation), Sn-Co, Sn-Ag and Sn-Bi during Spacelab missions in 1983 and 1985 are presented. The results of experiments carried out without the disturbing effect of convection are compared with those found in literature (experiments or calculations carried out from liquid structure models) [fr

Dynamic scaling for the growth of non-equilibrium fluctuations during thermophoretic diffusion in microgravity.

Science.gov (United States)

Cerbino, Roberto; Sun, Yifei; Donev, Aleksandar; Vailati, Alberto

2015-09-30

Diffusion processes are widespread in biological and chemical systems, where they play a fundamental role in the exchange of substances at the cellular level and in determining the rate of chemical reactions. Recently, the classical picture that portrays diffusion as random uncorrelated motion of molecules has been revised, when it was shown that giant non-equilibrium fluctuations develop during diffusion processes. Under microgravity conditions and at steady-state, non-equilibrium fluctuations exhibit scale invariance and their size is only limited by the boundaries of the system. In this work, we investigate the onset of non-equilibrium concentration fluctuations induced by thermophoretic diffusion in microgravity, a regime not accessible to analytical calculations but of great relevance for the understanding of several natural and technological processes. A combination of state of the art simulations and experiments allows us to attain a fully quantitative description of the development of fluctuations during transient diffusion in microgravity. Both experiments and simulations show that during the onset the fluctuations exhibit scale invariance at large wave vectors. In a broader range of wave vectors simulations predict a spinodal-like growth of fluctuations, where the amplitude and length-scale of the dominant mode are determined by the thickness of the diffuse layer.

High-school Student Teams in a National NASA Microgravity Science Competition

Science.gov (United States)

DeLombard, Richard; Hodanbosi, Carol; Stocker, Dennis

2003-01-01

The Dropping In a Microgravity Environment or DIME competition for high-school-aged student teams has completed the first year for nationwide eligibility after two regional pilot years. With the expanded geographic participation and increased complexity of experiments, new lessons were learned by the DIME staff. A team participating in DIME will research the field of microgravity, develop a hypothesis, and prepare a proposal for an experiment to be conducted in a NASA microgravity drop tower. A team of NASA scientists and engineers will select the top proposals and then the selected teams will design and build their experiment apparatus. When completed, team representatives will visit NASA Glenn in Cleveland, Ohio to operate their experiment in the 2.2 Second Drop Tower and participate in workshops and center tours. NASA participates in a wide variety of educational activities including competitive events. There are competitive events sponsored by NASA (e.g. NASA Student Involvement Program) and student teams mentored by NASA centers (e.g. For Inspiration and Recognition of Science and Technology Robotics Competition). This participation by NASA in these public forums serves to bring the excitement of aerospace science to students and educators.Researchers from academic institutions, NASA, and industry utilize the 2.2 Second Drop Tower at NASA Glenn Research Center in Cleveland, Ohio for microgravity research. The researcher may be able to complete the suite of experiments in the drop tower but many experiments are precursor experiments for spaceflight experiments. The short turnaround time for an experiment's operations (45 minutes) and ready access to experiment carriers makes the facility amenable for use in a student program. The pilot year for DIME was conducted during the 2000-2001 school year with invitations sent out to Ohio- based schools and organizations. A second pilot year was conducted during the 2001-2002 school year for teams in the six-state region

Plant Production Systems for Microgravity: Critical Issues in Water, Air, and Solute Transport Through Unsaturated Porous Media

Science.gov (United States)

Steinberg, Susan L. (Editor); Ming, Doug W. (Editor); Henninger, Don (Editor)

2002-01-01

This NASA Technical Memorandum is a compilation of presentations and discussions in the form of minutes from a workshop entitled 'Plant Production Systems for Microgravity: Critical Issues in Water, Air, and Solute Transport Through Unsaturated Porous Media' held at NASA's Johnson Space Center, July 24-25, 2000. This workshop arose from the growing belief within NASA's Advanced Life Support Program that further advances and improvements in plant production systems for microgravity would benefit from additional knowledge of fundamental processes occurring in the root zone. The objective of the workshop was to bring together individuals who had expertise in various areas of fluid physics, soil physics, plant physiology, hardware development, and flight tests to identify, discuss, and prioritize critical issues of water and air flow through porous media in microgravity. Participants of the workshop included representatives from private companies involved in flight hardware development and scientists from universities and NASA Centers with expertise in plant flight tests, plant physiology, fluid physics, and soil physics.

Intracellular Zn(II) Intoxication Leads to Dysregulation of the PerR Regulon Resulting in Heme Toxicity in Bacillus subtilis

Science.gov (United States)

2016-01-01

Transition metal ions (Zn(II), Cu(II)/(I), Fe(III)/(II), Mn(II)) are essential for life and participate in a wide range of biological functions. Cellular Zn(II) levels must be high enough to ensure that it can perform its essential roles. Yet, since Zn(II) binds to ligands with high avidity, excess Zn(II) can lead to protein mismetallation. The major targets of mismetallation, and the underlying causes of Zn(II) intoxication, are not well understood. Here, we use a forward genetic selection to identify targets of Zn(II) toxicity. In wild-type cells, in which Zn(II) efflux prevents intoxication of the cytoplasm, extracellular Zn(II) inhibits the electron transport chain due to the inactivation of the major aerobic cytochrome oxidase. This toxicity can be ameliorated by depression of an alternate oxidase or by mutations that restrict access of Zn(II) to the cell surface. Conversely, efflux deficient cells are sensitive to low levels of Zn(II) that do not inhibit the respiratory chain. Under these conditions, intracellular Zn(II) accumulates and leads to heme toxicity. Heme accumulation results from dysregulation of the regulon controlled by PerR, a metal-dependent repressor of peroxide stress genes. When metallated with Fe(II) or Mn(II), PerR represses both heme biosynthesis (hemAXCDBL operon) and the abundant heme protein catalase (katA). Metallation of PerR with Zn(II) disrupts this coordination, resulting in depression of heme biosynthesis but continued repression of catalase. Our results support a model in which excess heme partitions to the membrane and undergoes redox cycling catalyzed by reduced menaquinone thereby resulting in oxidative stress. PMID:27935957

Common Effects on Follicular Thyroid Cancer Cells Exerted by Simulated Microgravity

DEFF Research Database (Denmark)

Svejgaard, Benjamin; Grimm, Daniela; Corydon, Thomas Juhl

2015-01-01

This study focuses on gravity-sensitive proteins of two human follicular cancer cell lines (ML-1; RO82-W-1), which were exposed to simulated microgravity (s-μg) on two different machines. Changes in protein cytoskeletal structure, growth patterns and protein expression in response to s-μg were...

Monitoring the Microgravity Environment Quality On-Board the International Space Station Using Soft Computing Techniques

Science.gov (United States)

Jules, Kenol; Lin, Paul P.

2001-01-01

This paper presents an artificial intelligence monitoring system developed by the NASA Glenn Principal Investigator Microgravity Services project to help the principal investigator teams identify the primary vibratory disturbance sources that are active, at any moment in time, on-board the International Space Station, which might impact the microgravity environment their experiments are exposed to. From the Principal Investigator Microgravity Services' web site, the principal investigator teams can monitor via a graphical display, in near real time, which event(s) is/are on, such as crew activities, pumps, fans, centrifuges, compressor, crew exercise, platform structural modes, etc., and decide whether or not to run their experiments based on the acceleration environment associated with a specific event. This monitoring system is focused primarily on detecting the vibratory disturbance sources, but could be used as well to detect some of the transient disturbance sources, depending on the events duration. The system has built-in capability to detect both known and unknown vibratory disturbance sources. Several soft computing techniques such as Kohonen's Self-Organizing Feature Map, Learning Vector Quantization, Back-Propagation Neural Networks, and Fuzzy Logic were used to design the system.

Microgravity modulation effects on free convection problems LBM simulation

Science.gov (United States)

Javadi, Khodayar; Kazemi, Koorosh

2018-01-01

In this paper, microgravity modulation effects on free convection in a cavity are investigated using the lattice Boltzmann method. In order to create microgravity modulation, a sinusoidal time-dependent function is considered. Parameters of the flow are chosen such that the maximum Rayleigh number approaches 106. The natural frequency of the system is obtained at first. Afterwards, effects of different frequencies on the flow and heat transfer fields are investigated in detail. Results are presented in four different frequency ratios categorized as (1) ω*=1/200 , 1/100 , 1/20 , and 1/10 ; (2) ω*=1/8 , 1/5 , 1/3 , and 1/2 ; (3) ω* = 0.75, 0.85, and 0.95; and (4) the last one is considered for natural frequency as a special case of ω* = 1. Furthermore, the fast Fourier transformation is used to describe the cavity flow behavior. The results indicated that at low frequency, the system has enough time to adapt itself with the gravity modulation while historical effects do not disappear. Increasing the frequency changes the behavior of the system and different flow patterns appear. Finally, at the natural frequency (ω* = 1), all system modes are stimulated and a strange flow pattern is formed.

Results and perspectives of particle transport measurements in gases in microgravity

Science.gov (United States)

Vedernikov, Andrei; Balapanov, Daniyar; Beresnev, Sergey

2016-07-01

Solid or liquid particles floating in a gas belong to dispersed systems, most often referred to as aerosols or dust clouds. They are widely spread in nature, involving both environmental and technological issues. They attract growing attention in microgravity, particularly in complex plasma, simulation of protoplanetary dust clouds, atmospheric aerosol, etc. Brownian random walk, motion of particles in gravity, electrostatic and magnetic fields, are well defined. We present the survey showing that the quantitative description of a vast variety of other types of motion is much less accurate, often known only in a limited region of parameters, sometimes described by the contradictory models, poorly verified experimentally. It is true even for the most extensively investigated transport phenomena - thermophoresis and photophoresis, not to say about diffusiophoresis, gravito-photophoresis, various other types of particle motion driven by physicochemical transformation and accommodation peculiarities on the particle-gas interface, combination of different processes. The number of publications grow very quickly, only those dealing with thermophoresis exceeded 300 in 2015. Hence, there is a strong need in high quality experimental data on particle transport properties with growing interest to expand the scope for non-isometric particles, agglomerates, dense clouds, interrelation with the two-phase flow dynamics. In most cases, the accuracy and sometimes the entire possibility of the measurement is limited by the presence of gravity. Floating particles have the density considerably different from that of the gas. They sediment, often with gliding and tumbling, that perturbs the motion trajectory, local hydrodynamic environment around particles, all together complicating definition of the response. Measurements at very high or very low Knudsen numbers (rarefied gas or too big particles) are of particular difficulty. Experiments assume creating a well-defined force, i

Microgravity research in plant biological systems: Realizing the potential of molecular biology

Science.gov (United States)

Lewis, Norman G.; Ryan, Clarence A.

1993-01-01

The sole all-pervasive feature of the environment that has helped shape, through evolution, all life on Earth is gravity. The near weightlessness of the Space Station Freedom space environment allows gravitational effects to be essentially uncoupled, thus providing an unprecedented opportunity to manipulate, systematically dissect, study, and exploit the role of gravity in the growth and development of all life forms. New and exciting opportunities are now available to utilize molecular biological and biochemical approaches to study the effects of microgravity on living organisms. By careful experimentation, we can determine how gravity perception occurs, how the resulting signals are produced and transduced, and how or if tissue-specific differences in gene expression occur. Microgravity research can provide unique new approaches to further our basic understanding of development and metabolic processes of cells and organisms, and to further the application of this new knowledge for the betterment of humankind.

Tests of Flammability of Cotton Fabrics and Expected Skin Burns in Microgravity

Science.gov (United States)

Cavanagh, Jane M.; Torvi, David A.; Gabriel, Kamiel S.; Ruff, Gary A.

2004-01-01

During a shuttle launch and other portions of space flight, astronauts wear specialized flame resistant clothing. However during most of their missions on board the Space Shuttle or International Space Station, astronauts wear ordinary clothing, such as cotton shirts and pants. As the behaviour of flames is considerably different in microgravity than under earth s gravity, fabrics are expected to burn in a different fashion in microgravity than when tested on earth. There is interest in determining how this change in burning behaviour may affect times to second and third degree burn of human skin, and how the results of standard fabric flammability tests conducted under earth s gravity correlate with the expected fire behaviour of textiles in microgravity. A new experimental apparatus was developed to fit into the Spacecraft Fire Safety Facility (SFSF), which is used on NASA s KC-135 low gravity aircraft. The new apparatus was designed to be similar to the apparatus used in standard vertical flammability tests of fabrics. However, rather than using a laboratory burner, the apparatus uses a hot wire system to ignite 200 mm high by 80 mm wide fabric specimens. Fabric temperatures are measured using thermocouples and/or an infrared imaging system, while flame spread rates are measured using real time observations or video. Heat flux gauges are placed between 7 and 13 mm away from the fabric specimen, so that heat fluxes from the burning fabric to the skin can be estimated, along with predicted times required to produce skin burns.

XRMON-GF: A novel facility for solidification of metallic alloys with in situ and time-resolved X-ray radiographic characterization in microgravity conditions

Science.gov (United States)

Nguyen-Thi, H.; Reinhart, G.; Salloum Abou Jaoude, G.; Mathiesen, R. H.; Zimmermann, G.; Houltz, Y.; Voss, D.; Verga, A.; Browne, D. J.; Murphy, A. G.

2013-07-01

As most of the phenomena involved during the growth of metallic alloys from the melt are dynamic, in situ and time-resolved X-ray imaging should be retained as the method of choice for investigating the solidification front evolution. On Earth, the gravity force is the major source of various disturbing effects (natural convection, buoyancy/sedimentation, and hydrostatic pressure) which can significantly modify or mask certain physical mechanisms. Therefore solidification under microgravity is an efficient way to eliminate such perturbations to provide unique benchmark data for the validation of models and numerical simulations. Up to now, in situ observation during microgravity solidification experiments were limited to the investigations on transparent organic alloys, using optical methods. On the other hand, in situ observation on metallic alloys generally required synchrotron facilities. This paper reports on a novel facility we have designed and developed to investigate directional solidification on metallic alloys in microgravity conditions with in situ X-ray radiography observation. The facility consists of a Bridgman furnace and an X-ray radiography device specifically devoted to the study of Al-based alloys. An unprecedented experiment was recently performed on board a sounding rocket, with a 6 min period of microgravity. Radiographs were successfully recorded during the entire experiment including the melting and solidification phases of the sample, with a Field-of-View of about 5 mm×5 mm, a spatial resolution of about 4 µm and a frequency of 2 frames per second. Some preliminary results are presented on the solidification of the Al-20 wt% Cu sample, which validate the apparatus and confirm the potential of in situ X-ray characterization for the investigation of dynamical phenomena in materials processing, and particularly for the studying of metallic alloys solidification.

Do gravity-related sensory information enable the enhancement of cortical proprioceptive inputs when planning a step in microgravity?

Directory of Open Access Journals (Sweden)

Anahid H Saradjian

Full Text Available We recently found that the cortical response to proprioceptive stimulation was greater when participants were planning a step than when they stood still, and that this sensory facilitation was suppressed in microgravity. The aim of the present study was to test whether the absence of gravity-related sensory afferents during movement planning in microgravity prevented the proprioceptive cortical processing to be enhanced. We reestablished a reference frame in microgravity by providing and translating a horizontal support on which the participants were standing and verified whether this procedure restored the proprioceptive facilitation. The slight translation of the base of support (lateral direction, which occurred prior to step initiation, stimulated at least cutaneous and vestibular receptors. The sensitivity to proprioceptive stimulation was assessed by measuring the amplitude of the cortical somatosensory-evoked potential (SEP, over the Cz electrode following the vibration of the leg muscle. The vibration lasted 1 s and the participants were asked to either initiate a step at the vibration offset or to remain still. We found that the early SEP (90-160 ms was smaller when the platform was translated than when it remained stationary, revealing the existence of an interference phenomenon (i.e., when proprioceptive stimulation is preceded by the stimulation of different sensory modalities evoked by the platform translation. By contrast, the late SEP (550 ms post proprioceptive stimulation onset was greater when the translation preceded the vibration compared to a condition without pre-stimulation (i.e., no translation. This suggests that restoring a body reference system which is impaired in microgravity allowed a greater proprioceptive cortical processing. Importantly, however, the late SEP was similarly increased when participants either produced a step or remained still. We propose that the absence of step-induced facilitation of

Fiscal 1999 international cooperation project report. R and D on convection control technology of glass melts by microgravity experiment; 1999 nendo bisho juryoku kankyo wo riyoshita glass yuekinai tairyu seigyo gijutsu no kenkyu kaihatsu seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

This R and D aims at development of convection simulation technology of glass melts based on measurement of accurate glass melt properties, and development of convection control technology of glass melts through the model experiment and small tank furnace experiment. Experiment was made on measurement of surface tension while levitating glass melts under the microgravity condition obtained by the drop tower of Japan Microgravity Center in Hokkaido. The shape of glass melt changes into a real sphere under the microgravity condition, and surface tension can be obtained by measuring its frequency, however, such frequency of glass could not be measured in this experiment. Levitation, fusion and oscillation experiment of glass was carried out by using an aero-acoustic levitator of CRT at Chicago. The experiment result is now in analysis. This study also aims the analysis in consideration of a surface tension flow effect. The calculation result showed generation of surface tension flow due to temperature gradient on a liquid surface. Various information were obtained through the model experiment using silicon oil, and glass convention observation by using a small tank furnace. (NEDO)

Free Cooling of a Granular Gas of Rodlike Particles in Microgravity

Science.gov (United States)

Harth, Kirsten; Trittel, Torsten; Wegner, Sandra; Stannarius, Ralf

2018-05-01

Granular gases as dilute ensembles of particles in random motion are at the basis of elementary structure-forming processes in the Universe, involved in many industrial and natural phenomena, and also excellent models to study fundamental statistical dynamics. The essential difference to molecular gases is the energy dissipation in particle collisions. Its most striking manifestation is the so-called granular cooling, the gradual loss of mechanical energy E (t ) in the absence of external excitation. We report an experimental study of homogeneous cooling of three-dimensional granular gases in microgravity. The asymptotic scaling E (t )∝t-2 obtained by Haff's minimal model [J. Fluid Mech. 134, 401 (1983), 10.1017/S0022112083003419] proves to be robust, despite the violation of several of its central assumptions. The shape anisotropy of the grains influences the characteristic time of energy loss quantitatively but not qualitatively. We compare kinetic energies in the individual degrees of freedom and find a slight predominance of translational motions. In addition, we observe a preferred rod alignment in the flight direction, as known from active matter or animal flocks.

FY 1997 report on the study on creation of inorganic materials under micro-gravity environment; 1997 nendo chosa hokokusho (bisho juryoku kankyo riyo muki zairyo no sosei kenkyu)

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

Study was made on creation of new functional inorganic materials under micro-gravity condition in an underground non-gravity experiment center to develop new production techniques of inorganic crystalline thin film, fine glass particle, anharmonic alloy, spherical semiconductor and surface modified semiconductor thin film. The micro-gravity observation result was analyzed numerically of interference fringes of Cu ion around an electrode during electrolysis. Experimental data relatively well agreed with computer simulation data. Prototype CdTe thin film was prepared by electrolysis. The size control condition of fine true spherical glass particles was clarified by micro-gravity evaporation/condensation of glass. Pb-Zn system alloys as an anharmonic alloy were prepared under micro-gravity condition, however, no compound of Pb and Zn was found. A production equipment of true spherical single-crystalline semiconductor by melting cubic Ge under micro-gravity condition, and basic data of heating condition were obtained. Surface modified semiconductor thin film was also obtained by micro-gravity laser annealing of SiGe prepared by plasma CVD. 23 refs., 65 figs., 6 tabs.

Cell proliferation of Paramecium tetraurelia under simulated microgravity

Science.gov (United States)

Sawai, S.; Mogami, Y.; Baba, S. A.

Paramecium is known to proliferate faster under microgravity in space and slower under hypergravity Experiments using axenic culture medium have demonstrated that the hypergravity affected directly on the proliferation of Paramecium itself Kato et al 2003 In order to assess the mechanisms underlying the physiological effects of gravity on cell proliferation Paramecium tetraurelia was grown under simulated microgravity performed by clinorotation and the time course of the proliferation was investigated in detail on the basis of the logistic analysis P tetraurelia was cultivated in a closed chamber in which cells were confined without air babbles reducing the shear stresses and turbulence under the rotation The chamber is made of quartz and silicone rubber film the former is for the optically-flat walls for the measurement of cell density by means of a non-invasive laser optical-slice method and the latter for gas exchange Because the closed chamber has an inner dimension of 3 times 3 times 60 mm Paramecium does not accumulate at the top of the chamber despite its negative gravitactic behavior We measured the cell density at regular time intervals without breaking the configuration of the chamber and analyzed the proliferation parameters by fitting the data to a logistic equation Clinorotation had the effects of reducing the proliferation of P tetraurelia It reduced both the saturation cell density and the maximum proliferation rate although it had little effect on the

Microgravity Flight: Accommodating Non-Human Primates

Science.gov (United States)

Dalton, Bonnie P.; Searby, Nancy; Ostrach, Louis

1995-01-01

Spacelab Life Sciences-3 (SLS-3) was scheduled to be the first United States man-tended microgravity flight containing Rhesus monkeys. The goal of this flight as in the five untended Russian COSMOS Bion flights and an earlier American Biosatellite flight, was to understand the biomedical and biological effects of a microgravity environment using the non-human primate as human surrogate. The SLS-3/Rhesus Project and COSMOS Primate-BIOS flights all utilized the rhesus monkey, Macaca mulatta. The ultimate objective of all flights with an animal surrogate has been to evaluate and understand biological mechanisms at both the system and cellular level, thus enabling rational effective countermeasures for future long duration human activity under microgravity conditions and enabling technical application to correction of common human physiological problems within earth's gravity, e.g., muscle strength and reloading, osteoporosis, immune deficiency diseases. Hardware developed for the SLS-3/Rhesus Project was the result of a joint effort with the French Centre National d'Etudes Spatiales (CNES) and the United States National Aeronautics and Space Administration (NASA) extending over the last decade. The flight hardware design and development required implementation of sufficient automation to insure flight crew and animal bio-isolation and maintenance with minimal impact to crew activities. A variety of hardware of varying functional capabilities was developed to support the scientific objectives of the original 22 combined French and American experiments, along with 5 Russian co-investigations, including musculoskeletal, metabolic, and behavioral studies. Unique elements of the Rhesus Research Facility (RRF) included separation of waste for daily delivery of urine and fecal samples for metabolic studies and a psychomotor test system for behavioral studies along with monitored food measurement. As in untended flights, telemetry measurements would allow monitoring of

High-Resolution X-Ray Tomography: A 3D Exploration Into the Skeletal Architecture in Mouse Models Submitted to Microgravity Constraints

Directory of Open Access Journals (Sweden)

Alessandra Giuliani

2018-03-01

Full Text Available Bone remodeling process consists in a slow building phase and in faster resorption with the objective to maintain a functional skeleton locomotion to counteract the Earth gravity. Thus, during spaceflights, the skeleton does not act against gravity, with a rapid decrease of bone mass and density, favoring bone fracture. Several studies approached the problem by imaging the bone architecture and density of cosmonauts returned by the different spaceflights. However, the weaknesses of the previously reported studies was two-fold: on the one hand the research suffered the small statistical sample size of almost all human spaceflight studies, on the other the results were not fully reliable, mainly due to the fact that the observed bone structures were small compared with the spatial resolution of the available imaging devices. The recent advances in high-resolution X-ray tomography have stimulated the study of weight-bearing skeletal sites by novel approaches, mainly based on the use of the mouse and its various strains as an animal model, and sometimes taking advantage of the synchrotron radiation support to approach studies of 3D bone architecture and mineralization degree mapping at different hierarchical levels. Here we report the first, to our knowledge, systematic review of the recent advances in studying the skeletal bone architecture by high-resolution X-ray tomography after submission of mice models to microgravity constrains.

Effects of simulated microgravity on circadian rhythm of caudal arterial pressure and heart rate in rats and their underlying mechanism

Directory of Open Access Journals (Sweden)

Li CHEN

2016-04-01

Full Text Available Objective 　To explore the effects of simulated microgravity on the circadian rhythm of rats' caudal arterial pressure and heart rate, and their underlying mechanism. Methods 　Eighteen male SD rats (aged 8 weeks were randomly assigned to control (CON and tail suspension (SUS group (9 each. Rats with tail suspension for 28 days were adopted as the animal model to simulate microgravity. Caudal arterial pressure and heart rate of rats were measured every 3 hours. The circadian difference of abdominal aorta contraction was measured by aortic ring test. Western blotting was performed to determine and compare the protein expression level of clock genes such as Per2 (Period2, Bmal1 (Aryl hydrocarbon receptor nuclear translocatorlike and dbp (D element binding protein in suprachiasmatic nucleus (SCN and abdominal aorta of rats in CON and SUS group at different time points. Results 　Compared with CON group, the caudal arterial pressure, both systolic and diastolic pressure, decreased significantly and the diurnal variability disappeared, meanwhile the heart rate increased obviously and also the diurnal variability disappeared in rats of SUS group. Compared with CON group, the contraction reactivity of abdominal aorta decreased with disappearence of the diurnal variability, and also the clock genes expression in SCN and abdominal aorta showed no diurnal variability in rats of SUS group. Conclusion 　Simulated microgravity may lead to circadian rhythm disorders in rats' cardiovascular system, which may be associated with the changes of the clock genes expression. DOI: 10.11855/j.issn.0577-7402.2016.04.06

Development of advanced diagnostics for characterization of burning droplets in microgravity

Science.gov (United States)

Sankar, Subramanian; Buermann, Dale H.; Bachalo, William D.

1995-01-01

Diagnostic techniques currently used for microgravity research are generally not as advanced as those used in earth based gravity experiments. Diagnostic techniques for measuring the instantaneous radial temperature profile (or temperature gradients) within the burning droplet do not exist. Over the past few years, Aerometrics has been researching and developing a rainbow thermometric technique for measuring the droplet temperatures of burning droplets. This technique has recently been integrated with the phase Doppler interferometric technique to yield a diagnostic instrument that can be used to simultaneously measure the size, velocity, and temperature of burning droplets in complex spray flames. Also, the rainbow thermometric technique has been recently integrated with a point-diffraction interferometric technique for measuring the instantaneous gas phase temperature field surrounding a burning droplet. These research programs, apart from being very successful, have also helped us identify other innovative techniques for the characterization of burning droplets. For example, new techniques have been identified for measuring the instantaneous regression rate of burning droplets. Also, there is the possibility of extracting the instantaneous radial temperature distribution or the temperature gradients within a droplet during transient heating. What is important is that these diagnostic techniques have the potential for making use of inexpensive, light-weight, and rugged devices such as diode lasers and linear CCD arrays. As a result, they can be easily packaged for incorporation into microgravity drop-test and flight-test facilities. Furthermore, with the use of linear CCD arrays, data rates as high as 10-100 kHz can be easily achieved. This data rate is orders of magnitude higher than what is currently achievable. In this research and development program, a compact and rugged diagnostic system will be developed that can be used to measure instantaneous fuel

Microgravity-induced modifications of the vestibuloocular reflex in Xenopus laevis tadpoles are related to development and the occurrence of tail lordosis.

Science.gov (United States)

Horn, Eberhard R

2006-08-01

During space flights, tadpoles of the clawed toad Xenopus laevis occasionally develop upward bended tails (tail lordosis). The tail lordosis disappears after re-entry to 1g within a couple of days. The mechanisms responsible for the induction of the tail lordosis are unknown; physical conditions such as weight de-loading or physiological factors such as decreased vestibular activity in microgravity might contribute. Microgravity (microg) also exerts significant effects on the roll-induced vestibuloocular reflex (rVOR). The rVOR was used to clarify whether tail lordosis is caused by physiological factors, by correlating the occurrence of microg-induced tail lordosis with the extent of microg-induced rVOR modifications. Post-flight recordings from three space flights (D-2 Spacelab mission, STS-55 in 1993; Shuttle-to-Mir mission SMM-06, STS-84 in 1997; French Soyuz taxi flight Andromède to ISS in 2001) were analyzed in these experiments. At onset of microgravity, tadpoles were at stages 25-28, 33-36 or 45. Parameters tested were rVOR gain (ratio between the angular eye movement and the lateral 30 degrees roll) and rVOR amplitude (maximal angular postural change of the eyes during a 360 degrees lateral roll). A ratio of 22-84% of tadpoles developed lordotic tails, depending on the space flight. The overall observation was that the rVOR of tadpoles with normal tails was either not affected by microgravity, or it was enhanced. In contrast, the rVOR of lordotic animals always revealed a depression. In particular, during post-flight days 1-11, tadpoles with lordotic tails from all three groups (25-28, 33-36 and 45) showed a lower rVOR gain and amplitude than the 1g-controls. The rVOR gain and amplitude of tadpoles from the groups 25-28 and 33-36 that developed normal tails was not affected by microgravity while the rVOR of microg-tadpoles from the stage-45 group with normal tails revealed a significant rVOR augmentation. (1) the vestibular system of tadpoles with lordotic

Contributions of microgravity test results to the design of spacecraft fire-safety systems

Science.gov (United States)

Friedman, Robert; Urban, David L.

1993-01-01

Experiments conducted in spacecraft and drop towers show that thin-sheet materials have reduced flammability ranges and flame-spread rates under quiescent low-gravity environments (microgravity) compared to normal gravity. Furthermore, low-gravity flames may be suppressed more easily by atmospheric dilution or decreasing atmospheric total pressure than their normal-gravity counterparts. The addition of a ventilating air flow to the low-gravity flame zone, however, can greatly enhance the flammability range and flame spread. These results, along with observations of flame and smoke characteristics useful for microgravity fire-detection 'signatures', promise to be of considerable value to spacecraft fire-safety designs. The paper summarizes the fire detection and suppression techniques proposed for the Space Station Freedom and discusses both the application of low-gravity combustion knowledge to improve fire protection and the critical needs for further research.

Dynamical behavior of surface tension on rotating fluids in low and microgravity environments

Science.gov (United States)

Hung, R. J.; Tsao, Y. D.; Hong, B. B.; Leslie, F. W.

1989-01-01

Consideration is given to the time-dependent evolutions of the free surface profile (bubble shapes) of a cylindrical container, partially filled with a Newtonian fluid of constant density, rotating about its axis of symmetry in low and microgravity environments. The dynamics of the bubble shapes are calculated for four cases: linear time-dependent functions of spin-up and spin-down in low and microgravity, linear time-dependent functions of increasing and decreasing gravity at high and low rotating cylinder speeds, time-dependent step functions of spin-up and spin-down in low gravity, and sinusoidal function oscillation of the gravity environment in high and low rotating cylinder speeds. It is shown that the computer algorithms developed by Hung et al. (1988) may be used to simulate the profile of time-dependent bubble shapes under variations of centrifugal, capillary, and gravity forces.

Contributions of Microgravity Test Results to the Design of Spacecraft Fire Safety Systems

Science.gov (United States)

Friedman, Robert; Urban, David L.

1993-01-01

Experiments conducted in spacecraft and drop towers show that thin-sheet materials have reduced flammability ranges and flame-spread rates under quiescent low-gravity environments (microgravity) as compared to normal gravity. Furthermore, low-gravity flames may be suppressed more easily by atmospheric dilution or decreasing atmospheric total pressure than their normal-gravity counterparts. The addition of a ventilating air flow to the low-gravity flame zone, however, can greatly enhance the flammability range and flame spread. These results, along with observations of flame and smoke characteristics useful for microgravity fire-detection 'signatures', promise to be of considerable value to spacecraft fire-safety designs. The paper summarizes the fire detection and suppression techniques proposed for the Space Station Freedom and discusses both the application of low-gravity combustion knowledge to improve fire protection and the critical needs for further research.

Plant cell proliferation and growth are altered by microgravity conditions in spaceflight

NARCIS (Netherlands)

Matia, I.; Gonzalez-Camacho, F.; Herranz, R.; Kiss, J.Z.; Gasset, G.; van Loon, J.J.W.A.; Marco, R.; Medina, F.J.

2010-01-01

Seeds of Arabidopsis thaliana were sent to space and germinated in orbit. Seedlings grew for 4 d and were then fixed in-flight with paraformaldehyde. The experiment was replicated on the ground in a Random Positioning Machine, an effective simulator of microgravity. In addition, samples from a

Simulated microgravity activates MAPK pathways in fibroblasts cultured on microgrooved surface topography

NARCIS (Netherlands)

Loesberg, W.A.; Walboomers, X.F.; van Loon, J.J.W.A.; Jansen, J.A.

2008-01-01

This study evaluated in vitro the differences in morphological behaviour between fibroblast cultured on smooth and microgrooved substrata (groove depth: 0.5 mu m, width: I pm), which were subjected to simulated microgravity. The aim of the study was to clarify which of these parameters was more

Simulated microgravity activates MAPK pathways in fibroblasts cultured on microgrooved surface topography.

NARCIS (Netherlands)

Loesberg, W.A.; Walboomers, X.F.; Loon, J.J.W.A. van; Jansen, J.A.

2008-01-01

This study evaluated in vitro the differences in morphological behaviour between fibroblast cultured on smooth and microgrooved substrata (groove depth: 0.5 mum, width: 1 mum), which were subjected to simulated microgravity. The aim of the study was to clarify which of these parameters was more

Heat Transfer to a Thin Solid Combustible in Flame Spreading at Microgravity

Science.gov (United States)

Bhattacharjee, S.; Altenkirch, R. A.; Olson, S. L.; Sotos, R. G.

1991-01-01

The heat transfer rate to a thin solid combustible from an attached diffusion flame, spreading across the surface of the combustible in a quiescent, microgravity environment, was determined from measurements made in the drop tower facility at NASA-Lewis Research Center. With first-order Arrhenius pyrolysis kinetics, the solid-phase mass and energy equations along with the measured spread rate and surface temperature profiles were used to calculate the net heat flux to the surface. Results of the measurements are compared to the numerical solution of the complete set of coupled differential equations that describes the temperature, species, and velocity fields in the gas and solid phases. The theory and experiment agree on the major qualitative features of the heat transfer. Some fundamental differences are attributed to the neglect of radiation in the theoretical model.

Deployment and testing of a second prototype expandable surgical chamber in microgravity

Science.gov (United States)

Markham, Sanford M.; Rock, John A.

1991-01-01

During microgravity exposure, two separate expandable surgical chambers were tested. Both chambers had been modified to fit the microgravity work station without extending over the sides of the table. Both chambers were attached to a portable laminar flow generator which served two purposes: to keep the chambers expanded during use; and to provide an operative area environment free of contamination. During the tests, the chambers were placed on various parts of a total body moulage to simulate management of several types of trauma. The tests consisted of cleansing contusions, debridement of burns, and suturing of lacerations. Also, indigo carmine dye was deliberately injected into the chamber during the tests to determine the ease of cleansing the chamber walls after contamination by escaping fluids. Upon completion of the tests, the expandable surgical chambers were deflated, folded, and placed in a flattened state back into their original containers for storage and later disposal. Results are briefly discussed.

Micro-gravity Isolation using only Electro-magnetic Actuators

DEFF Research Database (Denmark)

Vinther, D.; Alminde, Lars; Bisgaard, Morten

in the Sixth Student Parabolic Flight Campaign issued by the European Space Agency (ESA). The system consists of six custom made electro magnetic actuators which acts on the isolated platform based on the designed controller and their input from six accelerometers and six infrared position sensors. From......In this paper the design, construction and test of a free floating micro-gravity isolation platform to reduce the acceleration dose on zero gravity experiments on e.g. the International Space Station (ISS) is discussed. During the project a system is specified and constructed whereupon it is tested...

Micro-gravity Isolation using only Electro-magnetic Actuators

DEFF Research Database (Denmark)

Vinther, D.; Alminde, Lars; Bisgaard, Morten

2004-01-01

in the Sixth Student Parabolic Flight Campaign issued by the European Space Agency (ESA). The system consists of six custom made electro magnetic actuators which acts on the isolated platform based on the designed controller and their input from six accelerometers and six infrared position sensors. >From......In this paper the design, construction and test of a free floating micro-gravity isolation platform to reduce the acceleration dose on zero gravity experiments on e.g. the International Space Station (ISS) is discussed. During the project a system is specified and constructed whereupon it is tested...

Quantitative Measurements of CH* Concentration in Normal Gravity and Microgravity Coflow Laminar Diffusion Flames

Science.gov (United States)

Giassi, D.; Cao, S.; Stocker, D. P.; Takahashi, F.; Bennett, B. A.; Smooke, M. D.; Long, M. B.

2015-01-01

With the conclusion of the SLICE campaign aboard the ISS in 2012, a large amount of data was made available for the analysis of the effect of microgravity on laminar coflow diffusion flames. Previous work focused on the study of sooty flames in microgravity as well as the ability of numerical models to predict its formation in a simplified buoyancy-free environment. The current work shifts the investigation to soot-free flames, putting an emphasis on the chemiluminescence emission from electronically excited CH (CH*). This radical species is of significant interest in combustion studies: it has been shown that the CH* spatial distribution is indicative of the flame front position and, given the relatively simple diagnostic involved with its measurement, several works have been done trying to understand the ability of CH* chemiluminescence to predict the total and local flame heat release rate. In this work, a subset of the SLICE nitrogen-diluted methane flames has been considered, and the effect of fuel and coflow velocity on CH* concentration is discussed and compared with both normal gravity results and numerical simulations. Experimentally, the spectral characterization of the DSLR color camera used to acquire the flame images allowed the signal collected by the blue channel to be considered representative of the CH* emission centered around 431 nm. Due to the axisymmetric flame structure, an Abel deconvolution of the line-of-sight chemiluminescence was used to obtain the radial intensity profile and, thanks to an absolute light intensity calibration, a quantification of the CH* concentration was possible. Results show that, in microgravity, the maximum flame CH* concentration increases with the coflow velocity, but it is weakly dependent on the fuel velocity; normal gravity flames, if not lifted, tend to follow the same trend, albeit with different peak concentrations. Comparisons with numerical simulations display reasonably good agreement between measured and

Development of Active Learning Curriculum for CASPER's Microgravity Drop Tower

Science.gov (United States)

Carmona-Reyes, Jorge; Wang, Li; York, Judy; Matthews, Lorin; Laufer, Rene; Cook, Mike; Schmoke, Jimmy; Hyde, Truell

2016-10-01

As CASPER's new drop tower comes on line, plans for correlated educational research curricula are underway. CASPER's educational research team is working on developing curricula specific to the CASPER drop tower, modeled on a contest currently in use by (BEST) Robotics Inc. within central Texas independent school districts. The curricula integrates age specific use of computer programming software packages such as ``Scratch'' with industry standard communication protocols and augmented reality applications. Content is constructed around an earth and space science framework, covering subjects such as stars and galaxies, matter and energy, fusion and fission at a middle school level. CASPER faculty are partnering with the Region 12 Service Center; this combination provides a wide range of expertise that includes professional development, pedagogical methods, computational thinking in addition to microgravity and space science research expertise. The details of this work will be presented and samples of the manner in which it is impacting the CASPER research and educational outreach partnership will be discussed.

Microgravity changes in heart structure and cyclic-AMP metabolism

Science.gov (United States)

Philpott, D. E.; Fine, A.; Kato, K.; Egnor, R.; Cheng, L.

1985-01-01

The effects of microgravity on cardiac ultrastructure and cyclic AMP metabolism in tissues of rats flown on Spacelab 3 are reported. Light and electron microscope studies of cell structure, measurements of low and high Km phosphodiesterase activity, cyclic AMP-dependent protein kinase activity, and regulatory subunit compartmentation show significant deviations in flight animals when compared to ground controls. The results indicate that some changes have occurred in cellular responses associated with catecholamine receptor interactions and intracellular signal processing.

A Method for Assessing Material Flammability for Micro-Gravity Environments

Science.gov (United States)

Steinhaus, T.; Olenick, S. M.; Sifuentes, A.; Long, R. T.; Torero, J. L.

1999-01-01

On a spacecraft, one of the greatest fears during a mission is the outbreak of a fire. Since spacecraft are enclosed spaces and depend highly on technical electronics, a small fire could cause a large amount of damage. NASA uses upward flame spread as a "worst case scenario" evaluation for materials and the Heat and Visible Smoke Release Rates Test to assess the damage potential of a fire. Details of these tests and the protocols followed are provided by the "Flammability, Odor, Offgassing, and Compatibility Requirements and Test Procedures for Materials in Environments that Support Combustion" document. As pointed by Ohlemiller and Villa, the upward flame spread test does not address the effect of external radiation on ignition and spread. External radiation, as that coming from an overheated electrical component, is a plausible fire scenario in a space facility and could result in a reversal of the flammability rankings derived from the upward flame spread test. The "Upward Flame Propagation Test" has been the subject of strong criticism in the last few years. In many cases, theoretical exercises and experimental results have demonstrated the possibility of a reversal in the material flammability rankings from normal to micro-gravity. Furthermore, the need to incorporate information on the effects of external radiation and opposed flame spread when ranking materials based on their potential to burn in micro-gravity has been emphasized. Experiments conducted in a 2.2 second drop tower with an ethane burner in an air cross flow have emphasized that burning at the trailing edge is deterred in micro-gravity due to the decreased oxygen transport. For very low air flow velocities (U0.01 m/s). Only for U>0.l m/s extinction is observed at the leading edge (blow-off). Three dimensional numerical calculations performed for thin cellulose centrally ignited with an axisymmetric source have shown that under the presence of a forced flow slower than 0.035 m/s flames spreads

Gravisensitivity of various host plant -virus systems in simulated microgravity

Science.gov (United States)

Mishchenko, Lidiya; Taran, Oksana; Gordejchyk, Olga

In spite of considerable achievements in the study of gravity effects on plant development, some issues of gravitropism, like species-specificity and gravitation response remain unclear. The so-lution of such problems is connected with the aspects of life supply, in piloted space expeditions. The role of microgravity remains practically unstudied in the development of relations in the system host plant-virus, which are important for biotechnologies in crop production. It is ev-ident that the conditions of space flight can act as stressors, and the stress inducted by them favors the reactivation of latest herpes viruses in humans (satish et al., 2009) Viral infections of plants, which also can be in a latest state at certain stages of plant organism development, cause great damage to the growth and development of a host plant. Space flight conditions may cause both reactivation of latent viral infection in plants and its elimination, as it has been found by us for the system WSMW -wheat (Mishchenko et al., 2004). Our further research activities were concentrated on the identification of gravisensitivity in the system virus -potato plant to find out whether there was any species -related specificity of the reaction. In our research we used potato plants of Krymska Rosa, Zhuravushka, Agave, Belarosa, Kupalinka, and Zdubytok varieties. Simulated microgravity was ensured by clinostats KG-8 and Cycle -2. Gravisensitiv-ity has been studied the systems including PVX, PVM and PVY. Virus concentrations have been determined by ELISA using LOEWE reagents (placecountry-regionGermany). Virus iden-tification by morphological features were done by electron microscopy. For the system PVX -potato plant, we found the reduction in virus antigens content with prolonged clinostating. On the 18th day of cultivation, the plants showed a high level of X-virus antigen content on both stationary (control) and clinostated variants. On 36th and 47th day, depending plant variety, clinostated

Micro-gravity studies in archeo-prospecting of the Valley of the Kings, Luxor, Egypt

Czech Academy of Sciences Publication Activity Database

Issawy, E. A.; Tealeb, A. A.; Mrlina, Jan; Radwan, A. H.; Hassan, G. S.; Sakr, K. O.

- (2001), s. 201-212 ISSN 1110-6417 Institutional research plan: CEZ:AV0Z3012916 Keywords : micro-gravity investigations * archaeo-prospecting * Valley of the Kings * Egypt Subject RIV: DE - Earth Magnetism, Geodesy, Geography

Longevity of a Paramecium cell clone in space: Hypergravity experiments as a basis for microgravity experiments

Science.gov (United States)

Kato, Yuko; Mogami, Yoshihiro; Baba, Shoji A.

We proposed a space experiment aboard International Space Station to explore the effects of microgravity on the longevity of a Paramecium cell clone. Earlier space experiments in CYTOS and Space Lab D-1 demonstrated that Paramecium proliferated faster in space. In combination with the fact that aging process in Paramecium is largely related to the fission age, the results of the proliferation experiment in space may predict that the longevity of Paramecium decreases when measured by clock time. In preparation of the space experiment, we assessed the aging process under hypergravity, which is known to reduce the proliferation rate. As a result, the length of autogamy immaturity increased when measured by clock time, whereas it remained unchanged by fission age. It is therefore expected that autogamy immaturity in the measure of the clock time would be shortened under microgravity. Since the length of clonal life span of Paramecium is related to the length of autogamy immaturity, the result of hypergravity experiment supports the prediction that the clonal longevity of Paramecium under microgravity decreases. Effects of gravity on proliferation are discussed in terms of energetics of swimming during gravikinesis and gravitaxis of Paramecium.

Divergent regulation of CBF regulon on cold tolerance and plant phenotype in cassava overexpressing Arabidopsis CBF3 gene

Directory of Open Access Journals (Sweden)

Dong An

2016-12-01

Full Text Available Cassava is a tropical origin plant that is sensitive to chilling stress. In order to understand the CBF cold response pathway, a well-recognized regulatory mechanism in temperate plants, in cassava, overexpression of an Arabidopsis CBF3 gene is studied. This gene renders cassava increasingly tolerant to cold and drought stresses but is associated with retarded plant growth, leaf curling, reduced storage root yield, and reduced anthocyanin accumulation in a transcript abundance-dependent manner. Physiological analysis revealed that the transgenic cassava increased proline accumulation, reduced malondialdehyde production, and electrolyte leakage under cold stress. These transgenic lines also showed high relative water content when faced with drought. The expression of partial CBF-targeted genes in response to cold displayed temporal and spatial variations in the wild-type and transgenic plants: highly inducible in leaves and less altered in apical buds. In addition, anthocyanin accumulation was inhibited by downregulating the expression of genes involved in its biosynthesis and by interplaying between the CBF3 and the endogenous transcription factors. Thus, the heterologous CBF3 modulates the expression of stress-related genes and carries out a series of physiological adjustments under stressful conditions, showing a varied regulation pattern of CBF regulon from that of cassava CBFs.

FY 2000 report on research and development of combustion technology utilizing microgravity conditions for fuel diversification; 2000 nendo bisho juryoku kankyo wo riyoshita nenryo tayoka nensho gijutsu no kenkyu kaihatsu seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

This project is aimed at development of optimum combustion technology with diversified fuels, e.g., naphtha and LCO, for gas turbines and others as power sources for topographical energy supply. The combustion under the microgravity is also investigated using the underground facilities at Japan Microgravity Center. Described herein are the FY 2000 results. For construction of combustion model and simulation, the combustion reactions for various liquid fuels are simplified to calculate ignition delay, adiabatic flame temperature and laminar burning velocity with an error less than about 3%. The microgravity combustion experiments are conducted for spray dispersed into a cylinder, to find flame propagation velocities changing with the vaporization characteristics of liquid fuels, and also to construct the combustion models. The premixed turbulent combustion simulation program is developed using a probability density function and analyzed. Development of new combustion technologies includes the study themes of flame propagation and combustion of the air mixture of the multi-component fuel in which the spray exists, combustion characteristics of the droplets of diversified fuels, and combustion of gas turbines with diversified fuels. A propane/air mixture shows different flame propagation characteristics whether it contains kerosene or LCO droplets. The effects of electrical field intensity in the combustion zone on combustion of fuel droplets are elucidated. (NEDO)

Diverse Genetic Regulon of the Virulence-Associated Transcriptional Regulator MucR in Brucella abortus 2308

Science.gov (United States)

Caswell, Clayton C.; Elhassanny, Ahmed E. M.; Planchin, Emilie E.; Roux, Christelle M.; Weeks-Gorospe, Jenni N.; Ficht, Thomas A.; Dunman, Paul M.

2013-01-01

The Ros-type regulator MucR is one of the few transcriptional regulators that have been linked to virulence in Brucella. Here, we show that a Brucella abortus in-frame mucR deletion strain exhibits a pronounced growth defect during in vitro cultivation and, more importantly, that the mucR mutant is attenuated in cultured macrophages and in mice. The genetic basis for the attenuation of Brucella mucR mutants has not been defined previously, but in the present study the genes regulated by MucR in B. abortus have been elucidated using microarray analysis and real-time reverse transcription-PCR (RT-PCR). In B. abortus 2308, MucR regulates a wide variety of genes whose products may function in establishing and maintaining cell envelope integrity, polysaccharide biosynthesis, iron homeostasis, genome plasticity, and transcriptional regulation. Particularly notable among the MucR-regulated genes identified is arsR6 (nolR), which encodes a transcriptional regulator previously linked to virulence in Brucella melitensis 16 M. Importantly, electrophoretic mobility shift assays (EMSAs) determined that a recombinant MucR protein binds directly to the promoter regions of several genes repressed by MucR (including arsR6 [nolR]), and in Brucella, as in other alphaproteobacteria, MucR binds to its own promoter to repress expression of the gene that encodes it. Overall, these studies have uncovered the diverse genetic regulon of MucR in Brucella, and in doing so this work has begun to define the MucR-controlled genetic circuitry whose misregulation contributes to the virulence defect of Brucella mucR mutants. PMID:23319565

Rapid alterations of cell cycle control proteins in human T lymphocytes in microgravity

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Thiel Cora S

2012-01-01

Full Text Available Abstract In our study we aimed to identify rapidly reacting gravity-responsive mechanisms in mammalian cells in order to understand if and how altered gravity is translated into a cellular response. In a combination of experiments using "functional weightlessness" provided by 2D-clinostats and real microgravity provided by several parabolic flight campaigns and compared to in-flight-1g-controls, we identified rapid gravity-responsive reactions inside the cell cycle regulatory machinery of human T lymphocytes. In response to 2D clinorotation, we detected an enhanced expression of p21 Waf1/Cip1 protein within minutes, less cdc25C protein expression and enhanced Ser147-phosphorylation of cyclinB1 after CD3/CD28 stimulation. Additionally, during 2D clinorotation, Tyr-15-phosphorylation occurred later and was shorter than in the 1 g controls. In CD3/CD28-stimulated primary human T cells, mRNA expression of the cell cycle arrest protein p21 increased 4.1-fold after 20s real microgravity in primary CD4+ T cells and 2.9-fold in Jurkat T cells, compared to 1 g in-flight controls after CD3/CD28 stimulation. The histone acetyltransferase (HAT inhibitor curcumin was able to abrogate microgravity-induced p21 mRNA expression, whereas expression was enhanced by a histone deacetylase (HDAC inhibitor. Therefore, we suppose that cell cycle progression in human T lymphocytes requires Earth gravity and that the disturbed expression of cell cycle regulatory proteins could contribute to the breakdown of the human immune system in space.

Bursting Bubbles from Combustion of Thermoplastic Materials in Microgravity

Science.gov (United States)

Butler, K. B.

1999-01-01

Many thermoplastic materials in common use for a wide range of applications, including spacecraft, develop bubbles internally as they burn due to chemical reactions taking place within the bulk. These bubbles grow and migrate until they burst at the surface, forceably ejecting volatile gases and, occasionally, molten fuel. In experiments in normal gravity, Kashiwagi and Ohlemiller observed vapor jets extending a few centimeters from the surface of a radiatively heated polymethylmethacrylate (PMMA) sample, with some molten material ejected into the gas phase. These physical phenomena complicated the combustion process considerably. In addition to the non-steady release of volatiles, the depth of the surface layer affected by oxygen was increased, attributed to the roughening of the surface by bursting events. The ejection of burning droplets in random directions presents a potential fire hazard unique to microgravity. In microgravity combustion experiments on nylon Velcro fasteners and on polyethylene wire insulation, the presence of bursting fuel vapor bubbles was associated with the ejection of small particles of molten fuel as well as pulsations of the flame. For the nylon fasteners, particle velocities were higher than 30 cm/sec. The droplets burned robustly until all fuel was consumed, demonstrating the potential for the spread of fire in random directions over an extended distance. The sequence of events for a bursting bubble has been photographed by Newitt et al.. As the bubble reaches the fluid surface, the outer surface forms a dome while the internal bubble pressure maintains a depression at the inner interface. Liquid drains from the dome until it breaks into a cloud of droplets on the order of a few microns in size. The bubble gases are released rapidly, generating vortices in the quiescent surroundings and transporting the tiny droplets. The depression left by the escaping gases collapses into a central jet, which rises with a high velocity and may

Atom Interferometry with Ultracold Quantum Gases in a Microgravity Environment

Science.gov (United States)

Williams, Jason; D'Incao, Jose; Chiow, Sheng-Wey; Yu, Nan

2015-05-01

Precision atom interferometers (AI) in space promise exciting technical capabilities for fundamental physics research, with proposals including unprecedented tests of the weak equivalence principle, precision measurements of the fine structure and gravitational constants, and detection of gravity waves and dark energy. Consequently, multiple AI-based missions have been proposed to NASA, including a dual-atomic-species interferometer that is to be integrated into the Cold Atom Laboratory (CAL) onboard the International Space Station. In this talk, I will discuss our plans and preparation at JPL for the proposed flight experiments to use the CAL facility to study the leading-order systematics expected to corrupt future high-precision measurements of fundamental physics with AIs in microgravity. The project centers on the physics of pairwise interactions and molecular dynamics in these quantum systems as a means to overcome uncontrolled shifts associated with the gravity gradient and few-particle collisions. We will further utilize the CAL AI for proof-of-principle tests of systematic mitigation and phase-readout techniques for use in the next-generation of precision metrology experiments based on AIs in microgravity. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

Adrenomedullin is a key Protein Mediating Rotary Cell Culture System that Induces the Effects of Simulated Microgravity on Human Breast Cancer Cells

Science.gov (United States)

Chen, Li; Yang, Xi; Cui, Xiang; Jiang, Minmin; Gui, Yu; Zhang, Yanni; Luo, Xiangdong

2015-11-01

Microgravity or simulated microgravity promotes stem cell proliferation and inhibits differentiation. But, researchers have not yet been able to understand the underlying mechanism through which microgravity or simulated microgravity brings about stem cell proliferation and inhibition of differentiation. In this study, we investigated the effect of simulated microgravity (SMG) on MDA-MB-231 and MCF-7 human breast cancer cells using rotary cell culture system (RCCS). SMG induced a significant accumulation of these cancer cells in S phase of the cell cycle. But, compared with the static group, there was no effect on the overall growth rate of cells in the RCCS group. Furthermore, the expression of cyclin D1 was inhibited in the RCCS group, indicating that RCCS induced cell cycle arrest. In addition, RCCS also induced glycolytic metabolism by increasing the expression of adrenomedullin (ADM), but not HIF1 a. The addition of ADM further enhanced the effects of SMG, which was induced by RCCS. But, the addition of adrenomedullin antagonist (AMA) reversed these effects of SMG. Finally, our results proved that RCCS, which induced cells cycle arrest of breast cancer cells, enhanced glycolysis and upregulated the expression of ADM. But, this did not lead to an increase in hypoxia-inducible factor-1 a (HIF1 a) expression. Thus, we have uncovered a new mechanism for understanding the Warburg effect in breast cancer cells, this mechanism is not the same as hypoxia induced glycolysis.

Microgravity sciences application visiting scientist program

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Glicksman, Martin; Vanalstine, James

1995-01-01

Marshall Space Flight Center pursues scientific research in the area of low-gravity effects on materials and processes. To facilitate these Government performed research responsibilities, a number of supplementary research tasks were accomplished by a group of specialized visiting scientists. They participated in work on contemporary research problems with specific objectives related to current or future space flight experiments and defined and established independent programs of research which were based on scientific peer review and the relevance of the defined research to NASA microgravity for implementing a portion of the national program. The programs included research in the following areas: protein crystal growth, X-ray crystallography and computer analysis of protein crystal structure, optimization and analysis of protein crystal growth techniques, and design and testing of flight hardware.

Meniscus effect in microgravity materials processing

Science.gov (United States)

1998-01-01

While the microgravity environment of orbit eliminates a number of effects that impede the formation of materials on Earth, the change can also cause new, unwanted effects. A mysterious phenomenon, known as detached solidification, apparently stems from a small hydrostatic force that turns out to be pervasive. The contact of the solid with the ampoule transfers stress to the growing crystal and causing unwanted dislocations and twins. William Wilcox and Liya Regel of Clarkson University theorize that the melt is in contact with the ampoule wall, while the solid is not, and the melt and solid are cornected by a meniscus. Their work is sponsored by NASA's Office of Biological and Physical Researcxh, and builds on earlier work by Dr. David Larson of the State University of New York at Stony Brook.

Quenching Combustible Dust Mixtures Using Electric Particulate Suspensions (EPS): A New Testing Method For Microgravity

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Colver, Gerald M.; Greene, Nathanael; Shoemaker, David; Xu, Hua

2003-01-01

The Electric Particulate Suspension (EPS) is a combustion ignition system being developed at Iowa State University for evaluating quenching effects of powders in microgravity (quenching distance, ignition energy, flammability limits). Because of the high cloud uniformity possible and its simplicity, the EPS method has potential for "benchmark" design of quenching flames that would provide NASA and the scientific community with a new fire standard. Microgravity is expected to increase suspension uniformity even further and extend combustion testing to higher concentrations (rich fuel limit) than is possible at normal gravity. Two new combustion parameters are being investigated with this new method: (1) the particle velocity distribution and (2) particle-oxidant slip velocity. Both walls and (inert) particles can be tested as quenching media. The EPS method supports combustion modeling by providing accurate measurement of flame-quenching distance as a parameter in laminar flame theory as it closely relates to characteristic flame thickness and flame structure. Because of its design simplicity, EPS is suitable for testing on the International Space Station (ISS). Laser scans showing stratification effects at 1-g have been studied for different materials, aluminum, glass, and copper. PTV/PIV and a leak hole sampling rig give particle velocity distribution with particle slip velocity evaluated using LDA. Sample quenching and ignition energy curves are given for aluminum powder. Testing is planned for the KC-135 and NASA s two second drop tower. Only 1-g ground-based data have been reported to date.

Testing Microgravity Flight Hardware Concepts on the NASA KC-135

Science.gov (United States)

Motil, Susan M.; Harrivel, Angela R.; Zimmerli, Gregory A.

2001-01-01

This paper provides an overview of utilizing the NASA KC-135 Reduced Gravity Aircraft for the Foam Optics and Mechanics (FOAM) microgravity flight project. The FOAM science requirements are summarized, and the KC-135 test-rig used to test hardware concepts designed to meet the requirements are described. Preliminary results regarding foam dispensing, foam/surface slip tests, and dynamic light scattering data are discussed in support of the flight hardware development for the FOAM experiment.

Investigation of possible causes for human-performance degradation during microgravity flight

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Schroeder, James E.; Tuttle, Megan L.

1992-01-01

The results of the first year of a three year study of the effects of microgravity on human performance are given. Test results show support for the hypothesis that the effects of microgravity can be studied indirectly on Earth by measuring performance in an altered gravitational field. The hypothesis was that an altered gravitational field could disrupt performance on previously automated behaviors if gravity was a critical part of the stimulus complex controlling those behaviors. In addition, it was proposed that performance on secondary cognitive tasks would also degrade, especially if the subject was provided feedback about degradation on the previously automated task. In the initial experimental test of these hypotheses, there was little statistical support. However, when subjects were categorized as high or low in automated behavior, results for the former group supported the hypotheses. The predicted interaction between body orientation and level of workload in their joint effect on performance in the secondary cognitive task was significant for the group high in automatized behavior and receiving feedback, but no such interventions were found for the group high in automatized behavior but not receiving feedback, or the group low in automatized behavior.

Effect of Microgravity on Bone Tissue and Calcium Metabolism

Science.gov (United States)

1997-01-01

Session TA4 includes short reports concerning: (1) Human Bone Tissue Changes after Long-Term Space Flight: Phenomenology and Possible Mechanics; (2) Prediction of Femoral Neck Bone Mineral Density Change in Space; (3) Dietary Calcium in Space; (4) Calcium Metabolism During Extended-Duration Space Flight; (5) External Impact Loads on the Lower Extremity During Jumping in Simulated Microgravity and the Relationship to Internal Bone Strain; and (6) Bone Loss During Long Term Space Flight is Prevented by the Application of a Short Term Impulsive Mechanical Stimulus.

Materials Science Experiments Under Microgravity - A Review of History, Facilities, and Future Opportunities

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Stenzel, Ch.

2012-01-01

Materials science experiments have been a key issue already since the early days of research under microgravity conditions. A microgravity environment facilitates processing of metallic and semiconductor melts without buoyancy driven convection and sedimentation. Hence, crystal growth of semiconductors, solidification of metallic alloys, and the measurement of thermo-physical parameters are the major applications in the field of materials science making use of these dedicated conditions in space. In the last three decades a large number of successful experiments have been performed, mainly in international collaborations. In parallel, the development of high-performance research facilities and the technological upgrade of diagnostic and stimuli elements have also contributed to providing optimum conditions to perform such experiments. A review of the history of materials science experiments in space focussing on the development of research facilities is given. Furthermore, current opportunities to perform such experiments onboard ISS are described and potential future options are outlined.

Protein crystal growth results from the United States Microgravity Laboratory-1 mission

Science.gov (United States)

Delucas, Lawrence J.; Moore, K. M.; Vanderwoerd, M.; Bray, T. L.; Smith, C.; Carson, M.; Narayana, S. V. L.; Rosenblum, W. M.; Carter, D.; Clark, A. D, Jr.

1994-01-01

Protein crystal growth experiments have been performed by this laboratory on 18 Space Shuttle missions since April, 1985. In addition, a number of microgravity experiments also have been performed and reported by other investigators. These Space Shuttle missions have been used to grow crystals of a variety of proteins using vapor diffusion, liquid diffusion, and temperature-induced crystallization techniques. The United States Microgravity Laboratory - 1 mission (USML-1, June 25 - July 9, 1992) was a Spacelab mission dedicated to experiments involved in materials processing. New protein crystal growth hardware was developed to allow in orbit examination of initial crystal growth results, the knowledge from which was used on subsequent days to prepare new crystal growth experiments. In addition, new seeding hardware and techniques were tested as well as techniques that would prepare crystals for analysis by x-ray diffraction, a capability projected for the planned Space Station. Hardware that was specifically developed for the USML-1 mission will be discussed along with the experimental results from this mission.

Effect of simulated microgravity on E. coli K12 MG1655 growth and gene expression

Data.gov (United States)

National Aeronautics and Space Administration — This study demonstrates simulated microgravity effects on E. coli K 12 MG1655 when grown on LB medium supplemented with glycerol. The results imply that E. coli...

Influence of microgravity on root-cap regeneration and the structure of columella cells in Zea mays

Science.gov (United States)

Moore, R.; McClelen, C. E.; Fondren, W. M.; Wang, C. L.

1987-01-01

We launched imbibed seeds and seedlings of Zea mays into outer space aboard the space shuttle Columbia to determine the influence of microgravity on 1) root-cap regeneration, and 2) the distribution of amyloplasts and endoplasmic reticulum (ER) in the putative statocytes (i.e., columella cells) of roots. Decapped roots grown on Earth completely regenerated their caps within 4.8 days after decapping, while those grown in microgravity did not regenerate caps. In Earth-grown seedlings, the ER was localized primarily along the periphery of columella cells, and amyloplasts sedimented in response to gravity to the lower sides of the cells. Seeds germinated on Earth and subsequently launched into outer space had a distribution of ER in columella cells similar to that of Earth-grown controls, but amyloplasts were distributed throughout the cells. Seeds germinated in outer space were characterized by the presence of spherical and ellipsoidal masses of ER and randomly distributed amyloplasts in their columella cells. These results indicate that 1) gravity is necessary for regeneration of the root cap, 2) columella cells can maintain their characteristic distribution of ER in microgravity only if they are exposed previously to gravity, and 3) gravity is necessary to distribute the ER in columella cells of this cultivar of Z. mays.

Microgravity Science Glovebox (MSG) Space Science's Past, Present, and Future on the International Space Station (ISS)

Science.gov (United States)

Spivey, Reggie A.; Spearing, Scott F.; Jordan, Lee P.; McDaniel S. Greg

2012-01-01

The Microgravity Science Glovebox (MSG) is a double rack facility designed for microgravity investigation handling aboard the International Space Station (ISS). The unique design of the facility allows it to accommodate science and technology investigations in a "workbench" type environment. MSG facility provides an enclosed working area for investigation manipulation and observation in the ISS. Provides two levels of containment via physical barrier, negative pressure, and air filtration. The MSG team and facilities provide quick access to space for exploratory and National Lab type investigations to gain an understanding of the role of gravity in the physics associated research areas. The MSG is a very versatile and capable research facility on the ISS. The Microgravity Science Glovebox (MSG) on the International Space Station (ISS) has been used for a large body or research in material science, heat transfer, crystal growth, life sciences, smoke detection, combustion, plant growth, human health, and technology demonstration. MSG is an ideal platform for gravity-dependent phenomena related research. Moreover, the MSG provides engineers and scientists a platform for research in an environment similar to the one that spacecraft and crew members will actually experience during space travel and exploration. The MSG facility is ideally suited to provide quick, relatively inexpensive access to space for National Lab type investigations.

The Effects of Microgravity on Seated Height (Spinal Elongation)

Science.gov (United States)

Young, K. S.; Rajulu, S.

2011-01-01

ABSTRACT Many physiological factors, such as spinal elongation, fluid shifts, bone atrophy, and muscle loss, occur during an exposure to a microgravity environment. Spinal elongation is just one of the factors that can also affect the safety and performance of a crewmember while in space. Spinal elongation occurs due to the lack of gravity/compression on the spinal column. This allows for the straightening of the natural spinal curve. There is a possible fluid shift in the inter-vertebral disks that may also result in changes in height. This study aims at collecting the overall change in seated height for crewmembers exposed to a microgravity environment. During previous Programs, Apollo-Soyuz Test Project (ASTP) and Skylab, spinal elongation data was collected from a small number of subjects in a standing posture but were limited in scope. Data from these studies indicated a quick increase in stature during the first few days of weightlessness, after which stature growth reached a plateau resulting in up to a 3% increase of the original measurement [1-5]. However, this data was collected only for crewmembers in standing posture and not in a seated posture. Seated height may have a different effect than standing height due to a change in posture as well as due to a compounded effect of wearing restraints and a potential compression of the gluteal area. Seated height was deemed as a critical measurement in the design of the Constellation Program s (CxP) Crew Exploration Vehicle (CEV), called Orion which is now the point-of-departure vehicle for the Multi-Purpose Crew Vehicle (MPCV) Program; therefore a better understanding of the effects of microgravity on seated height is necessary. Potential changes in seated height that may not have impacted crew accommodation in previous Programs will have significant effects on crew accommodation due to the layout of seats in the Orion.. The current and existing configuration is such that the four crewmembers are stacked two by

Bubble Induced Disruption of a Planar Solid-Liquid Interface During Controlled Directional Solidification in a Microgravity Environment

Science.gov (United States)

Grugel, Richard N.; Brush, Lucien N.; Anilkumar, Amrutur V.

2013-01-01

Pore Formation and Mobility Investigation (PFMI) experiments were conducted in the microgravity environment aboard the International Space Station with the intent of better understanding the role entrained porosity/bubbles play during controlled directional solidification. The planar interface in a slowing growing succinonitrile - 0.24 wt% water alloy was being observed when a nitrogen bubble traversed the mushy zone and remained at the solid-liquid interface. Breakdown of the interface to shallow cells subsequently occurred, and was later evaluated using down-linked data from a nearby thermocouple. These results and other detrimental effects due to the presence of bubbles during solidification processing in a microgravity environment are presented and discussed.

Crystallization of uridine phosphorylase from Shewanella oneidensis MR-1 in the laboratory and under microgravity and preliminary X-ray diffraction analysis

International Nuclear Information System (INIS)

Safonova, Tatyana N.; Mordkovich, Nadezhda N.; Polyakov, Konstantin M.; Manuvera, Valentin A.; Veiko, Vladimir P.; Popov, Vladimir O.

2012-01-01

High-quality crystals of uridine phosphorylase from Shewanella oneidensis were grown under microgravity conditions. X-ray diffraction data were collected to a resolution of 0.95 Å. Uridine phosphorylase (UDP, EC 2.4.2.3), a key enzyme in the pyrimidine salvage pathway, catalyses the reversible phosphorolysis of uridine to uracil and ribose 1-phosphate. The gene expression of UDP from Shewanella oneidensis MR-1 was performed in the recipient strain Escherichia coli. The UDP protein was crystallized on earth (in the free form and in complex with uridine as the substrate) by the hanging-drop vapour-diffusion method at 296 K and under microgravity conditions (in the free form) aboard the Russian Segment of the International Space Station by the capillary counter-diffusion method. The data sets were collected to a resolution of 1.9 Å from crystals of the free form grown on earth, 1.6 Å from crystals of the complex with uridine and 0.95 Å from crystals of the free form grown under microgravity. All crystals belong to the space group P2 1 and have similar unit-cell parameters. The crystal of uridine phosphorylase grown under microgravity diffracted to ultra-high resolution and gave high-quality X-ray diffraction data

The effect of simulated microgravity on human mesenchymal stem cells cultured in an osteogenic differentiation system: a bioinformatics study.

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Sheyn, Dima; Pelled, Gadi; Netanely, Dvir; Domany, Eytan; Gazit, Dan

2010-11-01

One proposed strategy for bone regeneration involves ex vivo tissue engineering, accomplished using bone-forming cells, biodegradable scaffolds, and dynamic culture systems, with the goal of three-dimensional tissue formation. Rotating wall vessel bioreactors generate simulated microgravity conditions ex vivo, which lead to cell aggregation. Human mesenchymal stem cells (hMSCs) have been extensively investigated and shown to possess the potential to differentiate into several cell lineages. The goal of the present study was to evaluate the effect of simulated microgravity on all genes expressed in hMSCs, with the underlying hypothesis that many important pathways are affected during culture within a rotating wall vessel system. Gene expression was analyzed using a whole genome microarray and clustering with the aid of the National Institutes of Health's Database for Annotation, Visualization and Integrated Discovery database and gene ontology analysis. Our analysis showed 882 genes that were downregulated and 505 genes that were upregulated after exposure to simulated microgravity. Gene ontology clustering revealed a wide variety of affected genes with respect to cell compartment, biological process, and signaling pathway clusters. The data sets showed significant decreases in osteogenic and chondrogenic gene expression and an increase in adipogenic gene expression, indicating that ex vivo adipose tissue engineering may benefit from simulated microgravity. This finding was supported by an adipogenic differentiation assay. These data are essential for further understanding of ex vivo tissue engineering using hMSCs.

Development of experimental systems for material sciences under microgravity

Science.gov (United States)

Tanii, Jun; Obi, Shinzo; Kamimiyata, Yotsuo; Ajimine, Akio

1988-01-01

As part of the Space Experiment Program of the Society of Japanese Aerospace Companies, three experimental systems (G452, G453, G454) have been developed for materials science studies under microgravity by the NEC Corporation. These systems are to be flown as Get Away Special payloads for studying the feasibility of producing new materials. Together with the experimental modules carrying the hardware specific to the experiment, the three systems all comprise standard subsystems consisting of a power supply, sequence controller, temperature controller, data recorder, and video recorder.

Effects of Simulated Microgravity on Otolith Growth of Larval Zebrafish using a Rotating-Wall Vessel: Appropriate Rotation Speed and Fish Developmental Stage

Science.gov (United States)

Li, Xiaoyan; Anken, Ralf; Liu, Liyue; Wang, Gaohong; Liu, Yongding

2017-02-01

Stimulus dependence is a general feature of developing animal sensory systems. In this respect, it has extensively been shown earlier that fish inner ear otoliths can act as test masses as their growth is strongly affected by altered gravity such as hypergravity obtained using centrifuges, by (real) microgravity achieved during spaceflight or by simulated microgravity using a ground-based facility. Since flight opportunities are scarce, ground-based simulators of microgravity, using a wide variety of physical principles, have been developed to overcome this shortcoming. Not all of them, however, are equally well suited to provide functional weightlessness from the perspective of the biosystem under evaluation. Therefore, the range of applicability of a particular simulator has to be extensively tested. Earlier, we have shown that a Rotating-Wall Vessel (RWV) can be used to provide simulated microgravity for developing Zebrafish regarding the effect of rotation on otolith development. In the present study, we wanted to find the most effective speed of rotation and identify the appropriate developmental stage of Zebrafish, where effects are the largest, in order to provide a methodological basis for future in-depth analyses dedicated to the physiological processes underlying otolith growth at altered gravity. Last not least, we compared data on the effect of simulated microgravity on the size versus the weight of otoliths, since the size usually is measured in related studies due to convenience, but the weight more accurately approximates the physical capacity of an otolith. Maintaining embryos at 10 hours post fertilization for three days in the RWV, we found that 15 revolutions per minute (rpm) yielded the strongest effects on otolith growth. Maintenance of Zebrafish staged at 10 hpf, 1 day post fertilization (dpf), 4 dpf, 7 dpf and 14 dpf for three days at 15 rpm resulted in the most prominent effects in 7 dpf larvae. Weighing versus measuring the size of otoliths

Analysis of the ArcA regulon in anaerobically grown Salmonella enterica sv. Typhimurium

Directory of Open Access Journals (Sweden)

Porwollik Steffen

2011-03-01

Full Text Available Abstract Background Salmonella enterica serovar Typhimurium (S. Typhimurium is a Gram-negative pathogen that must successfully adapt to the broad fluctuations in the concentration of dissolved dioxygen encountered in the host. In Escherichia coli, ArcA (Aerobic Respiratory Control helps the cells to sense and respond to the presence of dioxygen. The global role of ArcA in E. coli is well characterized; however, little is known about its role in anaerobically grown S. Typhimurium. Results We compared the transcriptional profiles of the virulent wild-type (WT strain (ATCC 14028s and its isogenic arcA mutant grown under anaerobic conditions. We found that ArcA directly or indirectly regulates 392 genes (8.5% of the genome; of these, 138 genes are poorly characterized. Regulation by ArcA in S. Typhimurium is similar, but distinct from that in E. coli. Thus, genes/operons involved in core metabolic pathways (e.g., succinyl-CoA, fatty acid degradation, cytochrome oxidase complexes, flagellar biosynthesis, motility, and chemotaxis were regulated similarly in the two organisms. However, genes/operons present in both organisms, but regulated differently by ArcA in S. Typhimurium included those coding for ethanolamine utilization, lactate transport and metabolism, and succinate dehydrogenases. Salmonella-specific genes/operons regulated by ArcA included those required for propanediol utilization, flagellar genes (mcpAC, cheV, Gifsy-1 prophage genes, and three SPI-3 genes (mgtBC, slsA, STM3784. In agreement with our microarray data, the arcA mutant was non-motile, lacked flagella, and was as virulent in mice as the WT. Additionally, we identified a set of 120 genes whose regulation was shared with the anaerobic redox regulator, Fnr. Conclusion(s We have identified the ArcA regulon in anaerobically grown S. Typhimurium. Our results demonstrated that in S. Typhimurium, ArcA serves as a transcriptional regulator coordinating cellular metabolism, flagella

Proposed megakaryocytic regulon of p53: the genes engaged to control cell cycle and apoptosis during megakaryocytic differentiation

Science.gov (United States)

Apostolidis, Pani A.; Lindsey, Stephan; Miller, William M.

2012-01-01

During endomitosis, megakaryocytes undergo several rounds of DNA synthesis without division leading to polyploidization. In primary megakaryocytes and in the megakaryocytic cell line CHRF, loss or knock-down of p53 enhances cell cycling and inhibits apoptosis, leading to increased polyploidization. To support the hypothesis that p53 suppresses megakaryocytic polyploidization, we show that stable expression of wild-type p53 in K562 cells (a p53-null cell line) attenuates the cells' ability to undergo polyploidization during megakaryocytic differentiation due to diminished DNA synthesis and greater apoptosis. This suggested that p53's effects during megakaryopoiesis are mediated through cell cycle- and apoptosis-related target genes, possibly by arresting DNA synthesis and promoting apoptosis. To identify candidate genes through which p53 mediates these effects, gene expression was compared between p53 knock-down (p53-KD) and control CHRF cells induced to undergo terminal megakaryocytic differentiation using microarray analysis. Among substantially downregulated p53 targets in p53-KD megakaryocytes were cell cycle regulators CDKN1A (p21) and PLK2, proapoptotic FAS, TNFRSF10B, CASP8, NOTCH1, TP53INP1, TP53I3, DRAM1, ZMAT3 and PHLDA3, DNA-damage-related RRM2B and SESN1, and actin component ACTA2, while antiapoptotic CKS1B, BCL2, GTSE1, and p53 family member TP63 were upregulated in p53-KD cells. Additionally, a number of cell cycle-related, proapoptotic, and cytoskeleton-related genes with known functions in megakaryocytes but not known to carry p53-responsive elements were differentially expressed between p53-KD and control CHRF cells. Our data support a model whereby p53 expression during megakaryopoiesis serves to control polyploidization and the transition from endomitosis to apoptosis by impeding cell cycling and promoting apoptosis. Furthermore, we identify a putative p53 regulon that is proposed to orchestrate these effects. PMID:22548738

A survey of Type III restriction-modification systems reveals numerous, novel epigenetic regulators controlling phase-variable regulons; phasevarions

Science.gov (United States)

Atack, John M; Yang, Yuedong; Jennings, Michael P

2018-01-01

Abstract Many bacteria utilize simple DNA sequence repeats as a mechanism to randomly switch genes on and off. This process is called phase variation. Several phase-variable N6-adenine DNA-methyltransferases from Type III restriction-modification systems have been reported in bacterial pathogens. Random switching of DNA methyltransferases changes the global DNA methylation pattern, leading to changes in gene expression. These epigenetic regulatory systems are called phasevarions — phase-variable regulons. The extent of these phase-variable genes in the bacterial kingdom is unknown. Here, we interrogated a database of restriction-modification systems, REBASE, by searching for all simple DNA sequence repeats in mod genes that encode Type III N6-adenine DNA-methyltransferases. We report that 17.4% of Type III mod genes (662/3805) contain simple sequence repeats. Of these, only one-fifth have been previously identified. The newly discovered examples are widely distributed and include many examples in opportunistic pathogens as well as in environmental species. In many cases, multiple phasevarions exist in one genome, with examples of up to 4 independent phasevarions in some species. We found several new types of phase-variable mod genes, including the first example of a phase-variable methyltransferase in pathogenic Escherichia coli. Phasevarions are a common epigenetic regulation contingency strategy used by both pathogenic and non-pathogenic bacteria. PMID:29554328

Analysis of pulsed injection for microgravity receiver tank chilldown

Science.gov (United States)

Honkonen, Scott C.; Pietrzyk, Joe R.; Schuster, John R.

The dominant heat transfer mechanism during the hold phase of a tank chilldown cycle in a low-gravity environment is due to fluid motion persistence following the charge. As compared to the single-charge per vent cycle case, pulsed injection maintains fluid motion and the associated high wall heat transfer coefficients during the hold phase. As a result, the pulsed injection procedure appears to be an attractive method for reducing the time and liquid mass required to chill a tank. However, for the representative conditions considered, no significant benefit can be realized by using pulsed injection as compared to the single-charge case. A numerical model of the charge/hold/vent process was used to evaluate the pulsed injection procedure for tank chilldown in microgravity. Pulsed injection results in higher average wall heat transfer coefficients during the hold, as compared to the single-charge case. However, these high levels were not coincident with the maximum wall-to-fluid temperature differences, as in the single-charge case. For representative conditions investigated, the charge/hold/vent process is very efficient. A slightly shorter chilldown time was realized by increasing the number of pulses.

Effects of microgravity on renal stone risk assessment

Science.gov (United States)

Pietrzyk, R. A.; Pak, C. Y. C.; Cintron, N. M.; Whitson, P. A.

1992-01-01

Physiologic changes induced during human exposure to the microgravity environment of space may contribute to an increased potential for renal stone formation. Renal stone risk factors obtained 10 days before flight and immediately after return to earth indicated that calcium oxalate and uric acid stone-forming potential was increased after space flights of 4-10 days. These data describe the need for examining renal stone risk during in-flight phases of space missions. Because of limited availability of space and refrigerated storage on spacecraft, effective methods must be developed for collecting urine samples in-flight and for preserving (or storing) them at temperatures and under conditions commensurate with mission constraints.

Mechanobiologic Research in a Microgravity Environment Bioreactor

Science.gov (United States)

Guidi, A.; Dubini, G.; Tominetti, F.; Raimondi, M.

mechanical forces. For example, cartilage constructs have been cultured in spinner flasks under mixed or unmixed conditions, in simulated and in real microgravity. In these mixing studies, however, it is difficult to definitively quantify the effects of mixing-induced mechanical forces from those of convection-enhanced transport of nutrients to and of catabolites away from the cells. At the state of the art, the presence of a more controlled mechanical environment may be the condition required in order to study the biochemical and mechanical response of these biological systems. Such a controlled environment could lead to an advanced fluid dynamic design of the culture chamber that could both enhance the local mass transfer phenomena and match the needs of specific macroscopic mechanical effects in tissue development. The bioreactor is an excellent example of how the skills and resources of two distinctly different fields can complement each other. Microgravity can be used to enhance the formation of tissue like aggregates in specially designed bioreactors. Theoretical and experimental projects are under way to improve cell culture techniques using microgravity conditions experienced during space flights. Bioreactors usable under space flight conditions impose constructional principles which are different from those intended solely for ground applications. The Columbus Laboratory as part of the International Space Station (ISS) will be an evolving facility in low Earth orbit. Its mission is to support scientific, technological, and commercial activities in space. A goal of this research is to design a unique bioreactor for use sequentially from ground research to space research. One of the particularities of the simulated microgravity obtained through time averaging of the weight vector is that by varying the rotational velocity the same results can be obtained with a different value of g. One of the first applications of this technique in space biology was in fact the

Comparison of different techniques for in microgravity-a simple mathematic estimation of cardiopulmonary resuscitation quality for space environment.

Science.gov (United States)

Braunecker, S; Douglas, B; Hinkelbein, J

2015-07-01

Since astronauts are selected carefully, are usually young, and are intensively observed before and during training, relevant medical problems are rare. Nevertheless, there is a certain risk for a cardiac arrest in space requiring cardiopulmonary resuscitation (CPR). Up to now, there are 5 known techniques to perform CPR in microgravity. The aim of the present study was to analyze different techniques for CPR during microgravity about quality of CPR. To identify relevant publications on CPR quality in microgravity, a systematic analysis with defined searching criteria was performed in the PubMed database (http://www.pubmed.com). For analysis, the keywords ("reanimation" or "CPR" or "resuscitation") and ("space" or "microgravity" or "weightlessness") and the specific names of the techniques ("Standard-technique" or "Straddling-manoeuvre" or "Reverse-bear-hug-technique" or "Evetts-Russomano-technique" or "Hand-stand-technique") were used. To compare quality and effectiveness of different techniques, we used the compression product (CP), a mathematical estimation for cardiac output. Using the predefined keywords for literature search, 4 different publications were identified (parabolic flight or under simulated conditions on earth) dealing with CPR efforts in microgravity and giving specific numbers. No study was performed under real-space conditions. Regarding compression depth, the handstand (HS) technique as well as the reverse bear hug (RBH) technique met parameters of the guidelines for CPR in 1G environments best (HS ratio, 0.91 ± 0.07; RBH ratio, 0.82 ± 0.13). Concerning compression rate, 4 of 5 techniques reached the required compression rate (ratio: HS, 1.08 ± 0.11; Evetts-Russomano [ER], 1.01 ± 0.06; standard side straddle, 1.00 ± 0.03; and straddling maneuver, 1.03 ± 0.12). The RBH method did not meet the required criteria (0.89 ± 0.09). The HS method showed the highest cardiac output (69.3% above the required CP), followed by the ER technique (33

Quantitative Measurements of Electronically Excited CH Concentration in Normal Gravity and Microgravity Coflow Laminar Diffusion Flames

Science.gov (United States)

Giassi, D.; Cao, S.; Stocker, D. P.; Takahashi, F.; Bennett, B. A. V.; Smooke, M. D.; Long, M. B.

2015-01-01

With the conclusion of the SLICE campaign aboard the ISS in 2012, a large amount of data was made available for the analysis of the effect of microgravity on laminar coflow diffusion flames. Previous work focused on the study of sooty flames in microgravity as well as the ability of numerical models to predict its formation in a simplified buoyancy-free environment. The current work shifts the investigation to soot-free flames, putting an emphasis on the chemiluminescence emission from electronically excited CH (CH*). This radical species is of significant interest in combustion studies: it has been shown that the electronically excited CH spatial distribution is indicative of the flame front position and, given the relatively simple diagnostic involved with its measurement, several works have been done trying to understand the ability of electronically excited CH chemiluminescence to predict the total and local flame heat release rate. In this work, a subset of the SLICE nitrogen-diluted methane flames has been considered, and the effect of fuel and coflow velocity on electronically excited CH concentration is discussed and compared with both normal gravity results and numerical simulations. Experimentally, the spectral characterization of the DSLR color camera used to acquire the flame images allowed the signal collected by the blue channel to be considered representative of the electronically excited CH emission centered around 431 nm. Due to the axisymmetric flame structure, an Abel deconvolution of the line-of-sight chemiluminescence was used to obtain the radial intensity profile and, thanks to an absolute light intensity calibration, a quantification of the electronically excited CH concentration was possible. Results show that, in microgravity, the maximum flame electronically excited CH concentration increases with the coflow velocity, but it is weakly dependent on the fuel velocity; normal gravity flames, if not lifted, tend to follow the same trend

GenBank blastx search result: AK288454 [KOME

Lifescience Database Archive (English)

Full Text Available protein, putative response regulator of the competence regulon ComE1, putative histidine kinase of the competence regulon ComD1, comp...in, putative histidine kinase of the competence regulon ComD2, putative histidine kinase of the competence... regulon ComD3, putative response regulator of the competence regulon ComE2, putati...etence stimulating protein precursor, hypothetical protein, putative immunity prote

Adaptation of center of mass control under microgravity in a whole-body lifting task

NARCIS (Netherlands)

Kingma, I.; Toussaint, H.M.; Commissaris, D.A.C.M.; Savelsbergh, G.J.P.

1999-01-01

Human balance in stance is usually defined as the preservation of the vertical projection of the center of mass (COM) on the support area formed by the feet. Under microgravity conditions, the control of equilibrium seems to be no longer required. However, several reports indicate preservation of

FY1995 annual report on the advanced combustion science in microgravity field

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-03-01

Research was implemented continuously from the previous year on combustion equipment enabling advanced combustion technologies, by studying combustion in a microgravity field, for the purpose of preventing environmental pollution caused by diversification of energy sources and exhaust gasses. In joint studies with NASA, the 1995 themes were continued, for which tests were conducted 34 times using Japanese drop test equipment. Further, studies were added for flammability limits and flame dynamics of spherical flames in homogeneous and heterogeneous mixed fuels. The evaluation and analysis of the experiments and test data by the microgravity test equipment were such that laser ignitions of floating or fuel-oozing droplets, spherical/cylindrical combustion of liquid fuels, for example, were studied in regards to the combustion and vaporization process of fuel droplets, that high calorie fuel combustion in microgravitation field for example was investigated in relation to the combustion characteristics of high density fuels, that flame stability of lean premixed gasses for example was researched concerning flammability limit, and that NOx generation mechanism in liquid fuel combustion was looked into in connection with emission mechanisms of pollutant gaseous materials. (NEDO)

FY1996 annual report on the advanced combustion science in microgravity field

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

Research was implemented continuously from the previous year on combustion equipment enabling advanced combustion technologies, by studying combustion in a microgravity field, for the purpose of preventing environmental pollution caused by diversification of energy sources and exhaust gasses. In joint studies with NASA, the themes of the previous year were continued, for which tests were conducted 37 times using Japanese drop test equipment and 131 times using NASA's. The evaluation and analysis of the experiments and test data by the microgravity test equipment were, in addition to the themes of the previous year, such that micro observation for ignition/combustion mechanism of fuel spray droplets was made, as well as studies on fuel droplets combustion by a laser diagnostic device, concerning combustion of fuel droplets and vaporization process, that flame spread on solid substances was researched in relation to combustion characteristics of high density fuels, and that mixed gas combustion on a solid surface was studied in connection with the research on flammability limits. Furthermore, a study on combustion technology for gas turbines was added for the purpose of studying an advanced combustor. (NEDO)

Development of a computational model for astronaut reorientation.

Science.gov (United States)

Stirling, Leia; Willcox, Karen; Newman, Dava

2010-08-26

The ability to model astronaut reorientations computationally provides a simple way to develop and study human motion control strategies. Since the cost of experimenting in microgravity is high, and underwater training can lead to motions inappropriate for microgravity, these techniques allow for motions to be developed and well-understood prior to any microgravity exposure. By including a model of the current space suit, we have the ability to study both intravehicular and extravehicular activities. We present several techniques for rotating about the axes of the body and show that motions performed by the legs create a greater net rotation than those performed by the arms. Adding a space suit to the motions was seen to increase the resistance torque and limit the available range of motion. While rotations about the body axes can be performed in the current space suit, the resulting motions generated a reduced rotation when compared to the unsuited configuration. 2010 Elsevier Ltd. All rights reserved.

Searching the literature for proteins facilitates the identification of biological processes, if advanced methods of analysis are linked: a case study on microgravity-caused changes in cells.

Science.gov (United States)

Bauer, Johann; Bussen, Markus; Wise, Petra; Wehland, Markus; Schneider, Sabine; Grimm, Daniela

2016-07-01

More than one hundred reports were published about the characterization of cells from malignant and healthy tissues, as well as of endothelial cells and stem cells exposed to microgravity conditions. We retrieved publications about microgravity related studies on each type of cells, extracted the proteins mentioned therein and analyzed them aiming to identify biological processes affected by microgravity culture conditions. The analysis revealed 66 different biological processes, 19 of them were always detected when papers about the four types of cells were analyzed. Since a response to the removal of gravity is common to the different cell types, some of the 19 biological processes could play a role in cellular adaption to microgravity. Applying computer programs, to extract and analyze proteins and genes mentioned in publications becomes essential for scientists interested to get an overview of the rapidly growing fields of gravitational biology and space medicine.

Experimental Investigation of Flow Condensation in Microgravity

Science.gov (United States)

Lee, Hyoungsoon; Park, Ilchung; Konishi, Christopher; Mudawar, Issam; May, Rochelle I.; Juergens, Jeffery R.; Wagner, James D.; Hall, Nancy R.; Nahra, Henry K.; Hasan, Mohammed M.;

Modeling of microgravity combustion experiments

Science.gov (United States)

Buckmaster, John

1995-01-01

This program started in February 1991, and is designed to improve our understanding of basic combustion phenomena by the modeling of various configurations undergoing experimental study by others. Results through 1992 were reported in the second workshop. Work since that time has examined the following topics: Flame-balls; Intrinsic and acoustic instabilities in multiphase mixtures; Radiation effects in premixed combustion; Smouldering, both forward and reverse, as well as two dimensional smoulder.

Bubble Dynamics, Two-Phase Flow, and Boiling Heat Transfer in Microgravity

Science.gov (United States)

Chung, Jacob N.

1998-01-01

This report contains two independent sections. Part one is titled "Terrestrial and Microgravity Pool Boiling Heat Transfer and Critical heat flux phenomenon in an acoustic standing wave." Terrestrial and microgravity pool boiling heat transfer experiments were performed in the presence of a standing acoustic wave from a platinum wire resistance heater using degassed FC-72 Fluorinert liquid. The sound wave was created by driving a half wavelength resonator at a frequency of 10.15 kHz. Microgravity conditions were created using the 2.1 second drop tower on the campus of Washington State University. Burnout of the heater wire, often encountered with heat flux controlled systems, was avoided by using a constant temperature controller to regulate the heater wire temperature. The amplitude of the acoustic standing wave was increased from 28 kPa to over 70 kPa and these pressure measurements were made using a hydrophone fabricated with a small piezoelectric ceramic. Cavitation incurred during experiments at higher acoustic amplitudes contributed to the vapor bubble dynamics and heat transfer. The heater wire was positioned at three different locations within the acoustic field: the acoustic node, antinode, and halfway between these locations. Complete boiling curves are presented to show how the applied acoustic field enhanced boiling heat transfer and increased critical heat flux in microgravity and terrestrial environments. Video images provide information on the interaction between the vapor bubbles and the acoustic field. Part two is titled, "Design and qualification of a microscale heater array for use in boiling heat transfer." This part is summarized herein. Boiling heat transfer is an efficient means of heat transfer because a large amount of heat can be removed from a surface using a relatively small temperature difference between the surface and the bulk liquid. However, the mechanisms that govern boiling heat transfer are not well understood. Measurements of

mRNA expression profile in DLD-1 and MOLT-4 cancer cell lines cultured under Microgravity

Data.gov (United States)

National Aeronautics and Space Administration — DLD-1 and MOLT-4 cell lines were cultured in a Rotating cell culture system to simulate microgravity and mRNA expression profile was observed in comparison to Static...

Tomb of Nefertari signature in microgravity observations in the Valley of the Queens, Luxor, Egypt

Czech Academy of Sciences Publication Activity Database

Issawy, E. S. A.; Mrlina, Jan; Radwan, A. H.; Hassan, G. S.; Sakr, K. O.

2002-01-01

Roč. 1, č. 1 (2002), s. 23-32 ISSN 1687-0999 R&D Projects: GA ČR GA205/00/1470 Institutional research plan: CEZ:AV0Z3012916 Keywords : archaeological prospecting * Luxor * microgravity observations Subject RIV: DE - Earth Magnetism, Geodesy, Geography

Microgravity is the experimentl basis for understanding of the peculiarities of plant morphogenesis in the gravitational field

Science.gov (United States)

Demkiv, O. T.; Kordyum, Ye. L.; Khorkavtsiv, Ya. D.; Tairbekov, M. G.

Spiral growth of the gravisensitive protonema of Ceratodon purpureus moss is revealed in real microgravity during space flight. Caulonema differentiation with oblique cell partitions and deviation of an apical cell growth zone from the growth horizontal axis were shown to precede the stolon spiralization. The slope of subapical cell walls enables an apical cell to revolve on its long axis, overcome the substrate and gravity resistance, and become twisted. Investigations of C. purpureus, Burbula unguiculata and Physcomitrella patens protonema growth in the conditions of 1g, real and simulated microgravity (clinorotation) in darkness and under different light intensity and nutrient medium composition show that protonema morphogenesis is above all regulated by endogenous signals, action of which is concealed by gravity or light on the Earth.

Motor System Development Depends on Experience: A Microgravity Study of Rats

Science.gov (United States)

Walton, Kerry D.; Llinas, Rodolfo R.; Kalb, Robert; Hillman, Dean; DeFelipe, Javier; Garcia-Segura, Luis Miguel

2003-01-01

Animals move about their environment by sensing their surroundings and making adjustments according to need. All animals take the force of gravity into account when the brain and spinal cord undertake the planning and execution of movements. To what extent must animals learn to factor in the force of gravity when making neural calculations about movement? Are animals born knowing how to respond to gravity, or must the young nervous system learn to enter gravity into the equation? To study this issue, young rats were reared in two different gravitational environments (the one-G of Earth and the microgravity of low Earth orbit) that necessitated two different types of motor operations (movements) for optimal behavior. We inquired whether those portions of the young nervous system involved in movement, the motor system, can adapt to different gravitational levels and, if so, the cellular basis for this phenomenon. We studied two groups of rats that had been raised for 16 days in microgravity (eight or 14 days old at launch) and compared their walking and righting (ability to go from upside down to upright) and brain structure to those of control rats that developed on Earth. Flight rats were easily distinguished from the age-matched ground control rats in terms of both motor function and central nervous system structure. Mature surface righting predominated in control rats on the day of landing (R+O), while immature righting predominated in the flight rats on landing day and 30 days after landing. Some of these changes appear to be permanent. Several conclusions can be drawn from these studies: (1) Many aspects of motor behavior are preprogrammed into the young nervous system. In addition, several aspects of motor behavior are acquired as a function of the interaction of the developing organism and the rearing environment; (2) Widespread neuroanatomical differences between one-G- and microgravity-reared rats indicate that there is a structural basis for the adaptation

Profiling the patterns of miRNAs and transcriptome of human vasculature under micro-gravity: A template study using space science for solving health problems on the Earth

Directory of Open Access Journals (Sweden)

Suvro Chatterjee

2017-12-01

Present study infers that microgravity sensitized endothelial cells promotes angiogenesis, which can be used as a primer to ensure an efficient wound healing process. An in-depth deep sequencing study confirms that microgravity sensitizes the genome of human endothelial cells to promote angiogenesis and thereby wound healing.

RegPrecise 3.0--a resource for genome-scale exploration of transcriptional regulation in bacteria.

Science.gov (United States)

Novichkov, Pavel S; Kazakov, Alexey E; Ravcheev, Dmitry A; Leyn, Semen A; Kovaleva, Galina Y; Sutormin, Roman A; Kazanov, Marat D; Riehl, William; Arkin, Adam P; Dubchak, Inna; Rodionov, Dmitry A

2013-11-01

bacterial genomes. Analytical capabilities include exploration of: regulon content, structure and function; TF binding site motifs; conservation and variations in genome-wide regulatory networks across all taxonomic groups of Bacteria. RegPrecise 3.0 was selected as a core resource on transcriptional regulation of the Department of Energy Systems Biology Knowledgebase, an emerging software and data environment designed to enable researchers to collaboratively generate, test and share new hypotheses about gene and protein functions, perform large-scale analyses, and model interactions in microbes, plants, and their communities.

Genome Wide Expression Profiling of Cancer Cell Lines Cultured in Microgravity Reveals Significant Dysregulation of Cell Cycle and MicroRNA Gene Networks.

Directory of Open Access Journals (Sweden)

Prasanna Vidyasekar

Full Text Available Zero gravity causes several changes in metabolic and functional aspects of the human body and experiments in space flight have demonstrated alterations in cancer growth and progression. This study reports the genome wide expression profiling of a colorectal cancer cell line-DLD-1, and a lymphoblast leukemic cell line-MOLT-4, under simulated microgravity in an effort to understand central processes and cellular functions that are dysregulated among both cell lines. Altered cell morphology, reduced cell viability and an aberrant cell cycle profile in comparison to their static controls were observed in both cell lines under microgravity. The process of cell cycle in DLD-1 cells was markedly affected with reduced viability, reduced colony forming ability, an apoptotic population and dysregulation of cell cycle genes, oncogenes, and cancer progression and prognostic markers. DNA microarray analysis revealed 1801 (upregulated and 2542 (downregulated genes (>2 fold in DLD-1 cultures under microgravity while MOLT-4 cultures differentially expressed 349 (upregulated and 444 (downregulated genes (>2 fold under microgravity. The loss in cell proliferative capacity was corroborated with the downregulation of the cell cycle process as demonstrated by functional clustering of DNA microarray data using gene ontology terms. The genome wide expression profile also showed significant dysregulation of post transcriptional gene silencing machinery and multiple microRNA host genes that are potential tumor suppressors and proto-oncogenes including MIR22HG, MIR17HG and MIR21HG. The MIR22HG, a tumor-suppressor gene was one of the highest upregulated genes in the microarray data showing a 4.4 log fold upregulation under microgravity. Real time PCR validated the dysregulation in the host gene by demonstrating a 4.18 log fold upregulation of the miR-22 microRNA. Microarray data also showed dysregulation of direct targets of miR-22, SP1, CDK6 and CCNA2.

A mutant crp allele that differentially activates the operons of the fuc regulon in Escherichia coli.

Science.gov (United States)

Zhu, Y; Lin, E C

1988-05-01

L-Fucose is used by Escherichia coli through an inducible pathway mediated by a fucP-encoded permease, a fucI-encoded isomerase, a fucK-encoded kinase, and a fucA-encoded aldolase. The adolase catalyzes the formation of dihydroxyacetone phosphate and L-lactaldehyde. Anaerobically, lactaldehyde is converted by a fucO-encoded oxidoreductase to L-1,2-propanediol, which is excreted. The fuc genes belong to a regulon comprising four linked operons: fucO, fucA, fucPIK, and fucR. The positive regulator encoded by fucR responds to fuculose 1-phosphate as the effector. Mutants serially selected for aerobic growth on propanediol became constitutive in fucO and fucA [fucO(Con) fucA(Con)], but noninducible in fucPIK [fucPIK(Non)]. An external suppressor mutation that restored growth on fucose caused constitutive expression of fucPIK. Results from this study indicate that this suppressor mutation occurred in crp, which encodes the cyclic AMP-binding (or receptor) protein. When the suppressor allele (crp-201) was transduced into wild-type strains, the recipient became fucose negative and fucose sensitive (with glycerol as the carbon and energy source) because of impaired expression of fucA. The fucPIK operon became hyperinducible. The growth rate on maltose was significantly reduced, but growth on L-rhamnose, D-galactose, L-arabinose, glycerol, or glycerol 3-phosphate was close to normal. Lysogenization of fuc+ crp-201 cells by a lambda bacteriophage bearing crp+ restored normal growth ability on fucose. In contrast, lysogenization of [fucO(Con)fucA(Con)fucPIK(Non)crp-201] cells by the same phage retarded their growth on fucose.

Equilibrium Kinetics Studies and Crystallization Aboard the International Space Station (ISS) Using the Protein Crystallization Apparatus for Microgravity (PCAM)

Science.gov (United States)

Achari, Aniruddha; Roeber, Dana F.; Barnes, Cindy L.; Kundrot, Craig E.; Stinson, Thomas N. (Technical Monitor)

2002-01-01

Protein Crystallization Apparatus in Microgravity (PCAM) trays have been used in Shuttle missions to crystallize proteins in a microgravity environment. The crystallization experiments are 'sitting drops' similar to that in Cryschem trays, but the reservoir solution is soaked in a wick. From early 2001, crystallization experiments are conducted on the International Space Station using mission durations of months rather than two weeks on previous shuttle missions. Experiments were set up in April 2001 on Flight 6A to characterize the time crystallization experiments will take to reach equilibrium in a microgravity environment using salts, polyethylene glycols and an organic solvent as precipitants. The experiments were set up to gather data for a series of days of activation with different droplet volumes and precipitants. The experimental set up on ISS and results of this study will be presented. These results will help future users of PCAM to choose precipitants to optimize crystallization conditions for their target macromolecules for a particular mission with known mission duration. Changes in crystal morphology and size between the ground and space grown crystals of a protein and a protein -DNA complex flown on the same mission will also be presented.

Study of the influence of microgravity on the biological cells and molecular level; Seitai saibo bunshi level ni okeru bisho juryoku no eikyo ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-03-01

The shape of osteoblast, gene appearance, gene of rice blast, cellular fusion of plants, gravity acceptance mechanism of unicellular organisms, and physiological and immunity functions of mice were investigated under the microgravity condition. The influence of gravity on the vital reaction and the influence of microgravity on the crystallization of vital substances were also investigated. For the observation of osteoblast, the fluorescence dye reacted with Ca was well taken in the cells. The microgravity affected the stability of rice blast, but hardly affected the protoplast culture of mushroom. The reaction of ciliate against the gravity related to the specific gravity difference between cells and outer liquid. The level of adrenaline in blood of mice increased during the drop. The moving speed of trigger waves of chemical parallel slit formed at the BZ reaction under the microgravity became 60% to 80% of that on the ground. In the case of crystallization at the deposition agent concentration of 1% to 4%, the turbidity showing the degree of crystallization changed complicatedly. Nine processes of crystal growth were recognized. 21 refs., 55 figs., 1 tab.

Combustion of Solids in Microgravity: Results from the BASS-II Experiment

Science.gov (United States)

Ferkul, Paul V.; Bhattacharjee, Subrata; Fernandez-Pello, Carlos; Miller, Fletcher; Olson, Sandra L.; Takahashi, Fumiaki; T’ien, James S.

2014-01-01

The Burning and Suppression of Solids-II (BASS-II) experiment was performed on the International Space Station. Microgravity combustion tests burned thin and thick flat samples, acrylic slabs, spheres, and cylinders. The samples were mounted inside a small wind tunnel which could impose air flow speeds up to 53 cms. The wind tunnel was installed in the Microgravity Science Glovebox which supplied power, imaging, and a level of containment. The effects of air flow speed, fuel thickness, fuel preheating, and oxygen concentration on flame appearance, growth, spread rate, and extinction were examined in both the opposed and concurrent flow configuration. The flames are quite sensitive to air flow speed in the range 0 to 5 cms. They can be sustained at very low flow speeds of less than 1 cms, when they become dim blue and stable. In this state they are not particularly dangerous from a fire safety perspective, but they can flare up quickly with a sudden increase in air flow speed. Including earlier BASS-I results, well over one hundred tests have been conducted of the various samples in the different geometries, flow speeds, and oxygen concentrations. There are several important implications related to fundamental combustion research as well as spacecraft fire safety. This work was supported by the NASA Space Life and Physical Sciences Research and Applications Division (SLPSRA).

SPE (tm) regenerative hydrogen/oxygen fuel cells for extraterrestrial surface and microgravity applications

Science.gov (United States)

Mcelroy, J. F.

1990-01-01

Viewgraphs on SPE regenerative hydrogen/oxygen fuel cells for extraterrestrial surface and microgravity applications are presented. Topics covered include: hydrogen-oxygen regenerative fuel cell energy storage system; electrochemical cell reactions; SPE cell voltage stability; passive water removal SPE fuel cell; fuel cell performance; SPE water electrolyzers; hydrophobic oxygen phase separator; hydrophilic/electrochemical hydrogen phase separator; and unitized regenerative fuel cell.

Direct observation of spatially isothermal equiaxed solidification of an Al-Cu alloy in microgravity on board the MASER 13 sounding rocket

Science.gov (United States)

Murphy, A. G.; Mathiesen, R. H.; Houltz, Y.; Li, J.; Lockowandt, C.; Henriksson, K.; Melville, N.; Browne, D. J.

2016-11-01

For the first time, isothermal equiaxed solidification of a metallic alloy has been observed in situ in space, providing unique benchmark experimental data. The experiment was completed on board the MASER 13 sounding rocket, launched in December 2015, using a newly developed isothermal solidification furnace. A grain-refined Al-20 wt%Cu sample was fully melted and solidified during 360 s of microgravity and the solidification sequence was recorded using time-resolved X-radiography. Equiaxed nucleation, dendritic growth, solutal impingement, and eutectic transformation were thus observed in a gravity-free environment. Equiaxed nucleation was promoted through application of a controlled cooling rate of -0.05 K/s producing a 1D grain density of 6.5 mm-1, uniformly distributed throughout the field of view (FOV). Primary growth slowed to a visually imperceptible level at an estimated undercooling of 7 K, after which the cooling rate was increased to -1.0 K/s for the remainder of solidification and eutectic transformation, ensuring the sample was fully solidified inside the microgravity time window. The eutectic transformation commenced at the centre of the FOV proceeding radially outwards covering the entire FOV in 3 s Microgravity-based solidification is compared to an identical pre-flight ground-based experiment using the same sample and experiment timeline. The ground experiment was designed to minimise gravity effects, by choice of a horizontal orientation for the sample, so that any differences would be subtle. The first equiaxed nucleation occurred at an apparent undercooling of 0.6 K less than the equivalent event during microgravity. During primary equiaxed solidification, as expected, no buoyant grain motion was observed during microgravity, compared to modest grain rotation and reorientation observed during terrestrial-based solidification. However, when the cooling rate was increased from -0.05 K/s to -1.0 K/s during the latter stages of solidification, in

Monitoring the Microgravity Environment Quality On-board the International Space Station Using Soft Computing Techniques. Part 2; Preliminary System Performance Results

Science.gov (United States)

Jules, Kenol; Lin, Paul P.; Weiss, Daniel S.

2002-01-01

This paper presents the preliminary performance results of the artificial intelligence monitoring system in full operational mode using near real time acceleration data downlinked from the International Space Station. Preliminary microgravity environment characterization analysis result for the International Space Station (Increment-2), using the monitoring system is presented. Also, comparison between the system predicted performance based on ground test data for the US laboratory "Destiny" module and actual on-orbit performance, using measured acceleration data from the U.S. laboratory module of the International Space Station is presented. Finally, preliminary on-orbit disturbance magnitude levels are presented for the Experiment of Physics of Colloids in Space, which are compared with on ground test data. The ground test data for the Experiment of Physics of Colloids in Space were acquired from the Microgravity Emission Laboratory, located at the NASA Glenn Research Center, Cleveland, Ohio. The artificial intelligence was developed by the NASA Glenn Principal Investigator Microgravity Services Project to help the principal investigator teams identify the primary vibratory disturbance sources that are active, at any moment of time, on-board the International Space Station, which might impact the microgravity environment their experiments are exposed to. From the Principal Investigator Microgravity Services' web site, the principal investigator teams can monitor via a dynamic graphical display, implemented in Java, in near real time, which event(s) is/are on, such as crew activities, pumps, fans, centrifuges, compressor, crew exercise, structural modes, etc., and decide whether or not to run their experiments, whenever that is an option, based on the acceleration magnitude and frequency sensitivity associated with that experiment. This monitoring system detects primarily the vibratory disturbance sources. The system has built-in capability to detect both known

Behavior and reproduction of invertebrate animals during and after a long-term microgravity: space experiments using an Autonomous Biological System (ABS).

Science.gov (United States)

Ijiri, K; Mizuno, R; Narita, T; Ohmura, T; Ishikawa, Y; Yamashita, M; Anderson, G; Poynter, J; MacCallum, T

1998-12-01

Aquatic invertebrate animals such as Amphipods, Gastropods (pond snails), Ostracods and Daphnia (water flea) were placed in water-filled cylindrical vessels together with water plant (hornwort). The vessels were sealed completely and illuminated with a fluorescent lamp to activate the photosynthesis of the plant for providing oxygen within the vessels. Such ecosystem vessels, specially termed as Autonomous Biological System or ABS units, were exposed to microgravity conditions, and the behavior of the animals and their reproduction capacity were studied. Three space experiments were carried out. The first experiment used a Space shuttle only and it was a 10-day flight. The other two space experiments were carried out in the Space station Mir (Shuttle/Mir mission), and the flight units had been kept in microgravity for 4 months. Daphnia produced their offspring during a 10-day Shuttle flight. In the first Mir experiment, no Daphnia were detected when recovered to the ground. However, they were alive in the second Mir experiment. Daphnia were the most fragile species among the invertebrate animals employed in the present experiments. All the animals, i.e., Amphipods, pond snails, Ostracods and Daphnia had survived for 4 months in space, i.e., they had produced their offspring or repeated their life-cycles under microgravity. For the two Mir experiments, in both the flight and ground control ecosystem units, an inverse relationship was noted between the number of Amphipods and pond snails in each unit. Amphipods at 10 hours after the recovery to the ground frequently exhibited a movement of dropping straight-downward to the bottom of the units. Several Amphipods had their legs bent abnormally, which probably resulted from some physiological alterations during their embryonic development under microgravity. From the analysis of the video tape recorded in space, for Ostracods and Daphnia, a half of their population were looping under microgravity. Such looping animals

Diffusive transport processes in microgravity: the DCMIX project and the path to DCMIX-3

Science.gov (United States)

Triller, Thomas; Köhler, Werner

2016-07-01

Thermodiffusion describes the demixing of a system under the influence of an external temperature gradient which drives diffusive mass fluxes. Over the years, several (ground based) optical techniques have been employed for measuring thermodiffusion: Thermal Diffusion Forced Rayleigh Scattering (TDFRS), Optical Digital Interferometry (ODI) or Optical Beam Deflection (OBD). Most of these experiments use the same mechanism for the detection of demixing: light passes through a thermodiffusion cell, in which a well defined temperature gradient is applied on the sample. Diffusive fluxes change the concentration profile across the cell, and therefore the refractive index profile. This refractive index change is detected and mapped to the concentration using proper optical contrast factors. In particular ternary and higher multicomponent systems can suffer from thermosolutal convective instabilities. Therefore, the DCMIX project, a collaboration between several international research teams, ESA and Roscosmos, spearheads a measurement campaign on the ISS, utilizing SODI (Selectable Optical Diagnostics Instrument), a Mach-Zehnder interferometer inside the Microgravity Science Glovebox. Several ternary mixtures have been selected for measurement, all exhibiting unique properties. DCMIX-1 consisted of tetralin/isobutylbenzene/dodecane, a good model for hydrocarbon mixtures. DCMIX-2 was the system toluene/methanol/cyclohexane, which has a miscibility gap and allows to study critical behavior. DCMIX-3 is planned for the end of 2016 and will be an aqueous mixture of water/ethanol/triethylene-glycol. After a setback in 2014, when DCMIX-3 samples were lost with the explosion of the unmanned Orb3 vehicle, the project is now underway and will be ready for analysis at the beginning of 2017. As preparation for this, the methodology developed for data analysis has been applied to the DCMIX-1 data, especially aiming for the identification of stable quantities, which allow utilization of

Electrical Aspects of Flames in Microgravity Combustion

Science.gov (United States)

Dunn-Rankin, D.; Strayer, B.; Weinberg, F.; Carleton, F.

1999-01-01

A principal characteristic of combustion in microgravity is the absence of buoyancy driven flows. In some cases, such as for spherically symmetrical droplet burning, the absence of buoyancy is desirable for matching analytical treatments with experiments. In other cases, however, it can be more valuable to arbitrarily control the flame's convective environment independent of the environmental gravitational condition. To accomplish this, we propose the use of ion generated winds driven by electric fields to control local convection of flames. Such control can produce reduced buoyancy (effectively zero buoyancy) conditions in the laboratory in 1-g facilitating a wide range of laser diagnostics that can probe the system without special packaging required for drop tower or flight tests. In addition, the electric field generated ionic winds allow varying gravitational convection equivalents even if the test occurs in reduced gravity environments.

Dewetted growth of CdTe in microgravity (STS-95)

International Nuclear Information System (INIS)

Fiederle, M.; Babentsov, V.; Benz, K.W.; Duffar, T.; Dusserre, P.; Corregidor, V.; Dieguez, E.; Delaye, P.; Roosen, G.; Chevrier, V.; Launay, J.C.

2004-01-01

Two CdTe crystals had been grown in microgravity during the STS-95 mission. The growth configuration was dedicated to obtain dewetting of the crystals and to achieve high quality material. Background for the performed experiments was based on the theory of the dewetting and previous experience. The after flight characterization of the crystals has demonstrated existence of the dewetting areas of the crystals and their improved quality regarding the earth grown reference sample. The samples had been characterized by EDAX, Synchrotron X-ray topography, Photoluminescence and Optical and IR microscopy. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

A preview of a microgravity laser light scattering instrument

Science.gov (United States)

Meyer, W. V.; Ansari, R. R.

1991-01-01

The development of a versatile, miniature, modular light scattering instrument to be used in microgravity is described. The instrument will measure microscopic particles in the size range of thirty angstroms to above three microns. This modular instrument permits several configurations, each optimized for a particular experiment. In particular, a multiangle instrument will probably be mounted in a rack in the Space Shuttle and on the Space Station. It is possible that a Space Shuttle glove-box and a lap-top computer containing a correlator card can be used to perform a number of experiments and to demonstrate the technology needed for more elaborate investigations.

Deposition of CdTe films under microgravity: Foton M3 mission

Energy Technology Data Exchange (ETDEWEB)

Benz, K.W.; Croell, A. [Freiburger Materialforschungszentrum FMF, Albert-Ludwigs-Universitaet Freiburg (Germany); Zappettini, A.; Calestani, D. [CNR Parma, Instituto Materiali Speciali per Elettronica e Magnetismo IMEM, Fontani Parma (Italy); Dieguez, E. [Universidad Autonoma de Madrid (Spain). Departamento de Fisica de Materiales; Carotenuto, L.; Bassano, E. [Telespazio Napoli, Via Gianturco 31, 80146 Napoli (Italy); Fiederle, M.

2009-10-15

Experiments of deposition of CdTe films have been carried out under microgravity in the Russian Foton M3 mission. The influence of gravity has been studied with these experiments and compared to the results of simulations. The measured deposition rate could be confirmed by the theoretical results for lower temperatures. For higher temperatures the measured thickness of the deposited films was larger compared to the theoretical data. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Short-term, daily exposure to cold temperature may be an efficient way to prevent muscle atrophy and bone loss in a microgravity environment

Science.gov (United States)

Deng, Claudia; Wang, Ping; Zhang, Xiangming; Wang, Ya

2015-04-01

Microgravity induces less pressure on muscle/bone, which is a major reason for muscle atrophy as well as bone loss. Currently, physical exercise is the only countermeasure used consistently in the U.S. human space program to counteract the microgravity-induced skeletal muscle atrophy and bone loss. However, the routinely almost daily time commitment is significant and represents a potential risk to the accomplishment of other mission operational tasks. Therefore, development of more efficient exercise programs (with less time) to prevent astronauts from muscle atrophy and bone loss are needed. Consider the two types of muscle contraction: exercising forces muscle contraction and prevents microgravity-induced muscle atrophy/bone loss, which is a voluntary response through the motor nervous system; and cold temperature exposure-induced muscle contraction is an involuntary response through the vegetative nervous system, we formed a new hypothesis. The main purpose of this pilot study was to test our hypothesis that exercise at 4 °C is more efficient than at room temperature to prevent microgravity-induced muscle atrophy/bone loss and, consequently reduces physical exercise time. Twenty mice were divided into two groups with or without daily short-term (10 min × 2, at 12 h interval) cold temperature (4 °C) exposure for 30 days. The whole bodyweight, muscle strength and bone density were measured after terminating the experiments. The results from the one-month pilot study support our hypothesis and suggest that it would be reasonable to use more mice, in a microgravity environment and observe for a longer period to obtain a conclusion. We believe that the results from such a study will help to develop efficient exercise, which will finally benefit astronauts' heath and NASA's missions.

An Experimental Study of the Structure of Turbulent Non-Premixed Jet Flames in Microgravity

Science.gov (United States)

Boxx, Isaac; Idicheria, Cherian; Clemens, Noel

2000-11-01

The aim of this work is to investigate the structure of transitional and turbulent non-premixed jet flames under microgravity conditions. The microgravity experiments are being conducted using a newly developed drop rig and the University of Texas 1.5 second drop tower. The rig itself measures 16”x33”x38” and contains a co-flowing round jet flame facility, flow control system, CCD camera, and data/image acquisition computer. These experiments are the first phase of a larger study being conducted at the NASA Glenn Research Center 2.2 second drop tower facility. The flames being studied include methane and propane round jet flames at jet exit Reynolds numbers as high as 10,000. The primary diagnostic technique employed is emission imaging of flame luminosity using a relatively high-speed (350 fps) CCD camera. The high-speed images are used to study flame height, flame tip dynamics and burnout characteristics. Results are compared to normal gravity experimental results obtained in the same apparatus.

Pneumatic muscle actuator for resistive exercise in microgravity: test with a leg model.

Science.gov (United States)

Serres, Jennifer L; Phillips, Chandler A; Reynolds, David B; Mohler, Stanley R; Rogers, Dana B; Repperger, Daniel W; Gerschutz, Maria J

2010-02-01

A proof-of-concept demonstration is described in which a DC servomotor (simulating the quadriceps of a human operator) rotated a pulley 90 degrees (simulating knee extension). A pneumatic muscle actuator (PMA) generated an opposing force (antagonist) to the rotating pulley. One application of such a device is for use in microgravity environments because the PMA is compact, simple, and of relatively small mass (283 g). In addition, the operator can set a computer-controlled force-level range in response to individual user changes in exercise conditioning over time. A PMA was used in this study and interacted with a DC servomotor. For each trial, the PMA contracted in response to internal pressure. An input voltage profile activated the DC servomotor, resulting in the following three phases: an isokinetic counterclockwise pulley rotation of 90 degrees over 5 s (Phase I), the position was held for 5 s (Phase II), and an isokinetic clockwise rotation of 90 degrees over 5 s (Phase III). Root mean square error (RMSE) values were used to evaluate the pulley rotation. For Phase I, when the PMA pressures (in kPa) were 300, 450, and 575, the percent RMSE, respectively, were 5.24, 6.23, and 4.59. For Phase II, the percent RMSE were 2.81, 2.57, and 5.63, respectively. For Phase III, the percent RMSE were 5.69, 2.63, and 3.30, respectively. This study presents a demonstration of a PMA device that can enhance exercise by providing a wide range of resistive loads.

Sensorimotor Reorganizations of Arm Kinematics and Postural Strategy for Functional Whole-Body Reaching Movements in Microgravity

Directory of Open Access Journals (Sweden)

Thomas Macaluso

2017-10-01

Full Text Available Understanding the impact of weightlessness on human behavior during the forthcoming long-term space missions is of critical importance, especially when considering the efficiency of goal-directed movements in these unusual environments. Several studies provided a large set of evidence that gravity is taken into account during the planning stage of arm reaching movements to optimally anticipate its consequence upon the moving limbs. However, less is known about sensorimotor changes required to face weightless environments when individuals have to perform fast and accurate goal-directed actions with whole-body displacement. We thus aimed at characterizing kinematic features of whole-body reaching movements in microgravity, involving high spatiotemporal constraints of execution, to question whether and how humans are able to maintain the performance of a functional behavior in the standards of normogravity execution. Seven participants were asked to reach as fast and as accurately as possible visual targets while standing during microgravity episodes in parabolic flight. Small and large targets were presented either close or far from the participants (requiring, in the latter case, additional whole-body displacement. Results reported that participants successfully performed the reaching task with general temporal features of movement (e.g., movement speed close to land observations. However, our analyses also demonstrated substantial kinematic changes related to the temporal structure of focal movement and the postural strategy to successfully perform -constrained- whole-body reaching movements in microgravity. These immediate reorganizations are likely achieved by rapidly taking into account the absence of gravity in motor preparation and execution (presumably from cues about body limbs unweighting. Specifically, when compared to normogravity, the arm deceleration phase substantially increased. Furthermore, greater whole-body forward displacements

The Role of Parathyroid Hormone-Related Protein (PTHrP in Osteoblast Response to Microgravity: Mechanistic Implications for Osteoporosis Development.

Directory of Open Access Journals (Sweden)

Anne Camirand

Full Text Available Prolonged skeletal unloading through bedrest results in bone loss similar to that observed in elderly osteoporotic patients, but with an accelerated timeframe. This rapid effect on weight-bearing bones is also observed in astronauts who can lose up to 2% of their bone mass per month spent in Space. Despite the important implications for Spaceflight travelers and bedridden patients, the exact mechanisms involved in disuse osteoporosis have not been elucidated. Parathyroid hormone-related protein (PTHrP regulates many physiological processes including skeletal development, and has been proposed as a mechanosensor. To investigate the role of PTHrP in microgravity-induced bone loss, trabecular and calvarial osteoblasts (TOs and COs from Pthrp +/+ and -/- mice were subjected to actual Spaceflight for 6 days (Foton M3 satellite. Pthrp +/+, +/- and -/- osteoblasts were also exposed to simulated microgravity for periods varying from 6 days to 6 weeks. While COs displayed little change in viability in 0g, viability of all TOs rapidly decreased in inverse proportion to PTHrP expression levels. Furthermore, Pthrp+/+ TOs displayed a sharp viability decline after 2 weeks at 0g. Microarray analysis of Pthrp+/+ TOs after 6 days in simulated 0g revealed expression changes in genes encoding prolactins, apoptosis/survival molecules, bone metabolism and extra-cellular matrix composition proteins, chemokines, insulin-like growth factor family members and Wnt-related signalling molecules. 88% of 0g-induced expression changes in Pthrp+/+ cells overlapped those caused by Pthrp ablation in normal gravity, and pulsatile treatment with PTHrP1-36 not only reversed a large proportion of 0g-induced effects in Pthrp+/+ TOs but maintained viability over 6-week exposure to microgravity. Our results confirm PTHrP efficacy as an anabolic agent to prevent microgravity-induced cell death in TOs.

Physical Forces Modulate Oxidative Status and Stress Defense Meditated Metabolic Adaptation of Yeast Colonies: Spaceflight and Microgravity Simulations

Science.gov (United States)

Hammond, Timothy G.; Allen, Patricia L.; Gunter, Margaret A.; Chiang, Jennifer; Giaever, Guri; Nislow, Corey; Birdsall, Holly H.

2018-05-01

Baker's yeast ( Saccharomyces cerevisiae) has broad genetic homology to human cells. Although typically grown as 1-2mm diameter colonies under certain conditions yeast can form very large (10 + mm in diameter) or `giant' colonies on agar. Giant yeast colonies have been used to study diverse biomedical processes such as cell survival, aging, and the response to cancer pharmacogenomics. Such colonies evolve dynamically into complex stratified structures that respond differentially to environmental cues. Ammonia production, gravity driven ammonia convection, and shear defense responses are key differentiation signals for cell death and reactive oxygen system pathways in these colonies. The response to these signals can be modulated by experimental interventions such as agar composition, gene deletion and application of pharmaceuticals. In this study we used physical factors including colony rotation and microgravity to modify ammonia convection and shear stress as environmental cues and observed differences in the responses of both ammonia dependent and stress response dependent pathways We found that the effects of random positioning are distinct from rotation. Furthermore, both true and simulated microgravity exacerbated both cellular redox responses and apoptosis. These changes were largely shear-response dependent but each model had a unique response signature as measured by shear stress genes and the promoter set which regulates them These physical techniques permitted a graded manipulation of both convection and ammonia signaling and are primed to substantially contribute to our understanding of the mechanisms of drug action, cell aging, and colony differentiation.

Physical Forces Modulate Oxidative Status and Stress Defense Meditated Metabolic Adaptation of Yeast Colonies: Spaceflight and Microgravity Simulations

Science.gov (United States)

Hammond, Timothy G.; Allen, Patricia L.; Gunter, Margaret A.; Chiang, Jennifer; Giaever, Guri; Nislow, Corey; Birdsall, Holly H.

2017-12-01

Baker's yeast (Saccharomyces cerevisiae) has broad genetic homology to human cells. Although typically grown as 1-2mm diameter colonies under certain conditions yeast can form very large (10 + mm in diameter) or `giant' colonies on agar. Giant yeast colonies have been used to study diverse biomedical processes such as cell survival, aging, and the response to cancer pharmacogenomics. Such colonies evolve dynamically into complex stratified structures that respond differentially to environmental cues. Ammonia production, gravity driven ammonia convection, and shear defense responses are key differentiation signals for cell death and reactive oxygen system pathways in these colonies. The response to these signals can be modulated by experimental interventions such as agar composition, gene deletion and application of pharmaceuticals. In this study we used physical factors including colony rotation and microgravity to modify ammonia convection and shear stress as environmental cues and observed differences in the responses of both ammonia dependent and stress response dependent pathways We found that the effects of random positioning are distinct from rotation. Furthermore, both true and simulated microgravity exacerbated both cellular redox responses and apoptosis. These changes were largely shear-response dependent but each model had a unique response signature as measured by shear stress genes and the promoter set which regulates them These physical techniques permitted a graded manipulation of both convection and ammonia signaling and are primed to substantially contribute to our understanding of the mechanisms of drug action, cell aging, and colony differentiation.

A novel approach to reduce environmental noise in microgravity measurements using a Scintrex CG5

Science.gov (United States)

Boddice, Daniel; Atkins, Phillip; Rodgers, Anthony; Metje, Nicole; Goncharenko, Yuriy; Chapman, David

2018-05-01

The accuracy and repeatability of microgravity measurements for surveying purposes are affected by two main sources of noise; instrument noise from the sensor and electronics, and environmental sources of noise from anthropogenic activity, wind, microseismic activity and other sources of vibrational noise. There is little information in the literature on the quantitative values of these different noise sources and their significance for microgravity measurements. Experiments were conducted to quantify these sources of noise with multiple instruments, and to develop methodologies to reduce these unwanted signals thereby improving the accuracy or speed of microgravity measurements. External environmental sources of noise were found to be concentrated at higher frequencies (> 0.1 Hz), well within the instrument's bandwidth. In contrast, the internal instrumental noise was dominant at frequencies much lower than the reciprocal of the maximum integration time, and was identified as the limiting factor for current instruments. The optimum time for integration was found to be between 120 and 150 s for the instruments tested. In order to reduce the effects of external environmental noise on microgravity measurements, a filtering and despiking technique was created using data from noisy environments next to a main road and outside on a windy day. The technique showed a significant improvement in the repeatability of measurements, with between 40% and 50% lower standard deviations being obtained over numerous different data sets. The filtering technique was then tested in field conditions by using an anomaly of known size, and a comparison made between different filtering methods. Results showed improvements with the proposed method performing better than a conventional, or boxcar, averaging process. The proposed despiking process was generally found to be ineffective, with greater gains obtained when complete measurement records were discarded. Field survey results were

Novel active driven drop tower facility for microgravity experiments investigating production technologies on the example of substrate-free additive manufacturing