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Sample records for maneuver increases oxygenation

  1. Mixing effectiveness in the Apollo oxygen tanks of spin-up and rotation-reversal maneuvers

    NASA Technical Reports Server (NTRS)

    Baldwin, B.; Martin, E. D.; Reinhardt, W. A.; Sheaffer, Y.

    1971-01-01

    Two-dimensional simulations of stratified flows in the Apollo oxygen tanks have been used to estimate the mixing effectiveness of spin-up and rotation-reversal maneuvers. Calculations have been made for square and circular cylindrical tank geometries. Differences arising from heater position on the tank wall or near the center of the tank have been investigated. In the event of a prolonged period without normal maneuvers, the potential pressure decay (drop in pressure that would result from adiabatic mixing) can be suppressed by more than a factor of two through the use of spin-up and rotation-reversal maneuvers. Changes in rotation rate of order three revolutions per hour or greater are sufficient for this purpose.

  2. "Basal Cell Blanche": A Diagnostic Maneuver to Increase Early Detection of Basal Cell Carcinomas.

    PubMed

    Quach, Olivia Leigh; Barry, Megan; Roberts Cruse, Allison; Wilson, Barbara B

    2016-01-01

    Basal cell carcinomas represent one of the most common skin cancers and often present initially in the primary care setting. Subtle basal cell carcinomas may be difficult to detect, and early detection of these carcinomas remains important in limiting patient morbidity. In this article, we present a simple diagnostic maneuver, "basal cell blanche," to increase early detection of basal cell carcinomas. PMID:27170799

  3. Automatic Pilot For Flight-Test Maneuvers

    NASA Technical Reports Server (NTRS)

    Duke, Eugene L.; Jones, Frank P.; Roncoli, Ralph B.

    1992-01-01

    Autopilot replaces pilot during automatic maneuvers. Pilot, based on ground, flies aircraft to required altitude, then turns control over to autopilot. Increases quality of maneuvers significantly beyond that attainable through remote manual control by pilot on ground. Also increases quality of maneuvers because it performs maneuvers faster than pilot could and because it does not have to repeat poorly executed maneuvers.

  4. Terra Maneuvers

    Atmospheric Science Data Center

    2013-03-12

    ... 00:00:15 2013/044/14:05:24 Drag Makeup Maneuver #71 69991 002 ... 00:00:30 2012/032/14:55:00 Drag Makeup Maneuver #65 64486 229 ... 00:00:30 2012/096/15:00:00 Drag Makeup Maneuver #66 65418 229 ...

  5. Rotor noise in maneuvering flight

    NASA Astrophysics Data System (ADS)

    Chen, Hsuan-Nien

    The objective of this research is to understand the physics of rotor noise in the maneuvering flight. To achieve this objective, an integrated noise prediction system is constructed, namely GenHel-MFW-PSU-WOPWOP. This noise prediction system includes a flight simulation code, a high fidelity free vortex-wake code, and a rotor acoustic prediction code. By using this noise prediction system, rotor maneuver noise characteristics are identified. Unlike periodic rotor noise, a longer duration is required to describe rotor maneuver noise. The variation of helicopter motion, blade motion and blade airloads are all influencing the noise prediction results in both noise level and directivity in the maneuvering flight. In this research, two types of rotor maneuver noise are identified, steady maneuver noise and transient maneuver noise. In the steady maneuver, rotor noise corresponds to a steady maneuver condition, which has nearly steady properties in flight dynamics and aerodynamics. Transient maneuver noise is the result of the transition between two steady maneuvers. In a transient maneuver, the helicopter experiences fluctuations in airload and helicopter angular rates, which lead to excess rotor noise. Even though the transient maneuver only exists for a fairly short period of time, the corresponding transient maneuver noise could be significant when compared to steady maneuver noise. The blade tip vortices also present complex behaviors in the transient maneuver condition. With stronger vortex circulation strength and the potential for vortex bundling, blade vortex-interaction (BVI) noise may increase significantly during a transient maneuver. In this research, it is shown that even with small pilot controls, significant BVI noise can be generated during a transient flight condition. Finally, through this research, the importance of transient maneuver noise is demonstrated and recognized.

  6. Recruitment Maneuver Does not Increase the Risk of Ventilator Induced Lung Injury

    PubMed Central

    Akıncı, İbrahim Özkan; Atalan, Korkut; Tuğrul, Simru; Özcan, Perihan Ergin; Yılmazbayhan, Dilek; Kıran, Bayram; Basel, Ahmet; Telci, Lutfi; Çakar, Nahit

    2013-01-01

    Background: Mechanical ventilation (MV) may induce lung injury. Aims: To assess and evaluate the role of different mechanical ventilation strategies on ventilator-induced lung injury (VILI) in comparison to a strategy which includes recruitment manoeuvre (RM). Study design: Randomized animal experiment. Methods: Thirty male Sprague-Dawley rats were anaesthetised, tracheostomised and divided into 5 groups randomly according to driving pressures; these were mechanically ventilated with following peak alveolar opening (Pao) and positive end-expiratory pressures (PEEP) for 1 hour: Group 15-0: 15 cmH2O Pao and 0 cmH2O PEEP; Group 30-10: 30 cmH2O Pao and 10 cmH2O PEEP; Group 30-5: 30 cmH2O Pao and 5 cmH2O PEEP; Group 30-5&RM: 30 cmH2O Pao and 5 cmH2O PEEP with additional 45 cmH2O CPAP for 30 seconds in every 15 minutes; Group 45-0: 45 cmH2O Pao and 0 cmH2O PEEP Before rats were sacrificed, blood samples were obtained for the evaluation of cytokine and chemokine levels; then, the lungs were subsequently processed for morphologic evaluation. Results: Oxygenation results were similar in all groups; however, the groups were lined as follows according to the increasing severity of morphometric evaluation parameters: Group 15-0: (0±0.009) < Group 30-10: (0±0.14) < Group 30-5&RM: (1±0.12) < Group 30-5: (1±0.16) < Group 45-0: (2±0.16). Besides, inflammatory responses were the lowest in 30-5&RM group compared to all other groups. TNF-α, IL-1β, IL-6, MCP-1 levels were significantly different between group 30-5&RM and group 15-0 vs. group 45-0 in each group. Conclusion: RM with low PEEP reduces the risk of ventilator-induced lung injury with a lower release of systemic inflammatory mediators in response to mechanical ventilation. PMID:25207105

  7. Middle cerebral O₂ delivery during the modified Oxford maneuver increases with sodium nitroprusside and decreases during phenylephrine.

    PubMed

    Stewart, Julian M; Medow, Marvin S; DelPozzi, Andrew; Messer, Zachary R; Terilli, Courtney; Schwartz, Christopher E

    2013-06-01

    The modified Oxford maneuver is the reference standard for assessing arterial baroreflex function. The maneuver comprises a systemic bolus injection of 100 μg sodium nitroprusside (SNP) followed by 150 μg phenylephrine (PE). On the one hand, this results in an increase in oxyhemoglobin and total hemoglobin followed by a decrease within the cerebral sample volume illuminated by near-infrared spectroscopy (NIRS). On the other hand, it produces a decrease in cerebral blood flow velocity (CBFv) within the middle cerebral artery (MCA) during SNP and an increase in CBFv during PE as measured by transcranial Doppler ultrasound. To resolve this apparent discrepancy, we hypothesized that SNP dilates, whereas PE constricts, the MCA. We combined transcranial Doppler ultrasound of the right MCA with NIRS illuminating the right frontal cortex in 12 supine healthy subjects 18-24 yr old. Assuming constant O₂ consumption and venous saturation, as estimated by partial venous occlusion plethysmography, we used conservation of mass (continuity) equations to estimate the changes in arterial inflow (ΔQa) and venous outflow (ΔQv) of the NIRS-illuminated area. Oxyhemoglobin and total hemoglobin, respectively, increased by 13.6 ± 1.6 and 15.2 ± 1.4 μmol/kg brain tissue with SNP despite hypotension and decreased by 6 ± 1 and 7 ± 1 μmol/kg with PE despite hypertension. SNP increased ΔQa by 0.36 ± .03 μmol·kg(-1)·s(-1) (21.6 μmol·kg(-1)·min(-1)), whereas CBFv decreased from 71 ± 2 to 62 ± 2 cm/s. PE decreased ΔQa by 0.27 ± .2 μmol·kg(-1)·s(-1) (16.2 μmol·kg(-1)·min(-1)), whereas CBFv increased to 75 ± 3 cm/s. These results are consistent with dilation of the MCA by SNP and constriction by PE. PMID:23564308

  8. Middle cerebral O2 delivery during the modified Oxford maneuver increases with sodium nitroprusside and decreases during phenylephrine

    PubMed Central

    Medow, Marvin S.; DelPozzi, Andrew; Messer, Zachary R.; Terilli, Courtney; Schwartz, Christopher E.

    2013-01-01

    The modified Oxford maneuver is the reference standard for assessing arterial baroreflex function. The maneuver comprises a systemic bolus injection of 100 μg sodium nitroprusside (SNP) followed by 150 μg phenylephrine (PE). On the one hand, this results in an increase in oxyhemoglobin and total hemoglobin followed by a decrease within the cerebral sample volume illuminated by near-infrared spectroscopy (NIRS). On the other hand, it produces a decrease in cerebral blood flow velocity (CBFv) within the middle cerebral artery (MCA) during SNP and an increase in CBFv during PE as measured by transcranial Doppler ultrasound. To resolve this apparent discrepancy, we hypothesized that SNP dilates, whereas PE constricts, the MCA. We combined transcranial Doppler ultrasound of the right MCA with NIRS illuminating the right frontal cortex in 12 supine healthy subjects 18–24 yr old. Assuming constant O2 consumption and venous saturation, as estimated by partial venous occlusion plethysmography, we used conservation of mass (continuity) equations to estimate the changes in arterial inflow (ΔQa) and venous outflow (ΔQv) of the NIRS-illuminated area. Oxyhemoglobin and total hemoglobin, respectively, increased by 13.6 ± 1.6 and 15.2 ± 1.4 μmol/kg brain tissue with SNP despite hypotension and decreased by 6 ± 1 and 7 ± 1 μmol/kg with PE despite hypertension. SNP increased ΔQa by 0.36 ± .03 μmol·kg−1·s−1 (21.6 μmol·kg−1·min−1), whereas CBFv decreased from 71 ± 2 to 62 ± 2 cm/s. PE decreased ΔQa by 0.27 ± .2 μmol·kg−1·s−1 (16.2 μmol·kg−1·min−1), whereas CBFv increased to 75 ± 3 cm/s. These results are consistent with dilation of the MCA by SNP and constriction by PE. PMID:23564308

  9. Drag reducing chemical enables increased sea water injection without increasing the oxygen corrosion rate

    SciTech Connect

    McMahon, A.J.; Smith, P.S.; Lee, Y.

    1997-08-01

    Water soluble drag reducer chemicals have enabled significant increases in flow rates in many oilfield water injection systems. In some cases there is concern that this could lead to increased oxygen corrosion whenever the dissolved oxygen concentration strays above a typical injection target such as 20 ppb O{sub 2}. The effect of a chemical drag reducer on oxygen corrosion of carbon steel was examined in a large scale flow loop simulating a sea water injection line. Drag reduction (up to 48%) matched corrosion reduction (up to 39%). This means that drag reducer has a self compensating effect on oxygen corrosion: it permits higher flow rates without increasing the oxygen corrosion rate.

  10. [Study on anti +Gx respiratory maneuver and its training method].

    PubMed

    Xue, Yue-ying; You, Guang-xing; Wu, Bin; Liu, Xing-hua; Lu, Sheng-qiang; Xie, Bao-sheng

    2002-12-01

    Objective. To study the anti +Gx respiratory maneuver and its training method. Method. Seven young male subjects undertook the anti +Gx respiratory maneuver training. Their +Gx tolerances were examined on human centrifuge before and after training. The change of respiratory type, breath rate, electrocardiogram, heart rate, arterial oxygen saturation (SaO2), subjective symptom and vision were real-time monitored during the +Gx tolerance examination. Result. Compared with pre-training, the +Gx tolerance increased after training (P<0.05). Dyspnea and chest pain disappeared or obviously lightened and the magnitude of decrease of SaO2 decreased significantly (P<0.05). Conclusion. The above results suggested that the anti +Gx respiratory maneuver can effectively eliminate or alleviate dyspnea and chest pain induced by +Gx stress and increase human +Gx tolerance.

  11. Glucagon increases hepatic oxygen supply-demand ratio in pigs

    SciTech Connect

    Gelman, S.; Dillard, E.; Parks, D.A.

    1987-05-01

    The present study was performed on eight young pigs to test the hypothesis that glucagon increases hepatic oxygen supply to a greater extent than hepatic oxygen uptake, providing a better hepatic oxygen supply-demand relationship. The experiments were performed under pentobarbital sodium anesthesia and controlled ventilation. Splanchnic blood flow was studied using radioactive microspheres. Glucagon was administered in doses of 1 and 5 ..mu..g x kg/sup -1/ x min/sup -1/. During glucagon infusion, hepatic arterial blood flow substantially increased, splenic and pancreatic blood flows increased moderately, while stomach and intestinal blood flows, as well as portal blood flow did not change significantly. Shunting of both 9- and 15-..mu..m spheres through preportal tissues did not change significantly. Oxygen content in arterial or portal venous blood did not change significantly, while it increased in hepatic venous blood by 30%. There were no differences in the effects between the doses of glucagon administered. There was no correlation found between changes in hepatic oxygen supply and cardiac output or blood pressure. The changes observed during glucagon administration resulted in an increase in oxygen delivery to the liver and hepatic oxygen supply-uptake ratio.

  12. Females become infertile as the stored sperm's oxygen radicals increase

    PubMed Central

    Reinhardt, Klaus; Ribou, Anne-Cecile

    2013-01-01

    Predicting infertility is central to reproductive biology, medicine and evolutionary biology. In-vitro studies suggest that oxidative sperm damage causes infertility. Oxidative sperm damage can be reduced via two fundamental pathways: the removal of oxygen radicals by antioxidants, or the interference with cell metabolism to reduce the formation of oxygen radicals. Oxidative damage protection of spermatozoa should evolve frequently, especially during female sperm storage. However, in-vivo evidence linking oxidative protection and fertility is rare. We show that the intra-sperm production rate of oxygen radicals and the sperm metabolic rate were reduced in female bedbugs, Cimex lectularius, compared to males, and females laid fertile eggs. Females became infertile when sperm oxygen radicals and sperm metabolic rate increased to male levels. Our results link female fitness to sublethal sperm damage, imply adaptive benefits of interfering with sperm metabolism and offer the hypothesis that polyandry may serve to replace low-quality sperm.

  13. Engineering of pyranose dehydrogenase for increased oxygen reactivity.

    PubMed

    Krondorfer, Iris; Lipp, Katharina; Brugger, Dagmar; Staudigl, Petra; Sygmund, Christoph; Haltrich, Dietmar; Peterbauer, Clemens K

    2014-01-01

    Pyranose dehydrogenase (PDH), a member of the GMC family of flavoproteins, shows a very broad sugar substrate specificity but is limited to a narrow range of electron acceptors and reacts extremely slowly with dioxygen as acceptor. The use of substituted quinones or (organo)metals as electron acceptors is undesirable for many production processes, especially of food ingredients. To improve the oxygen reactivity, site-saturation mutagenesis libraries of twelve amino acids around the active site of Agaricus meleagris PDH were expressed in Saccharomyces cerevisiae. We established high-throughput screening assays for oxygen reactivity and standard dehydrogenase activity using an indirect Amplex Red/horseradish peroxidase and a DCIP/D-glucose based approach. The low number of active clones confirmed the catalytic role of H512 and H556. Only one position was found to display increased oxygen reactivity. Histidine 103, carrying the covalently linked FAD cofactor in the wild-type, was substituted by tyrosine, phenylalanine, tryptophan and methionine. Variant H103Y was produced in Pichia pastoris and characterized and revealed a five-fold increase of the oxygen reactivity. PMID:24614932

  14. Theophylline increases oxygen consumption during inspiratory resistive loading.

    PubMed

    Janssens, S; Derom, E; Vanhaecke, J; Decramer, M

    1995-04-01

    The effect of theophylline on diaphragmatic blood flow (Qdi) and oxygen consumption (VO2di) was studied in eight lightly anesthetized dogs during quiet breathing and inspiratory resistive loading. Qdi was determined with the radioactive microsphere tracer technique, and VO2di was calculated as the product of Qdi and the diaphragmatic arterio-venous oxygen difference. During quiet breathing, theophylline increased minute ventilation (9.3 +/- 1.7 versus 5.1 +/- 0.4 L/min), mean inspiratory flow (547 +/- 60 versus 378 +/- 56 ml/s), and duty cycle (0.270 +/- 0.042 versus 0.192 +/- 0.024) but did not significantly alter Qdi or VO2di. Conversely, Qdi increased significantly during loaded breathing compared with quiet breathing (37 +/- 4 versus 27 +/- 3 ml/100 g/min) and was further increased by theophylline (45 +/- 7 ml/100 g/min). Theophylline did not alter the tension-time index of the diaphragm (TTdi) during inspiratory resistive loading (0.054 +/- 0.006 versus 0.056 +/- 0.004, p NS) but resulted in a disproportionate and significant increase in VO2di (2.66 +/- 0.53 versus 1.78 +/- 0.26 ml/100 g/min). Similarly, total-body oxygen consumption (VO2TB) during inspiratory loading increased significantly after theophylline (24%), but the tension-time index of the inspiratory muscles (TTi), a measure of the total respiratory load, was unchanged. We conclude that theophylline significantly increases VO2di and VO2TB at the same TTdi and TTi during resistive loading. This enhanced energy expenditure needs consideration in the clinical management of pulmonary disorders that increase the work of breathing. PMID:7697222

  15. Maneuver Automation Software

    NASA Technical Reports Server (NTRS)

    Uffelman, Hal; Goodson, Troy; Pellegrin, Michael; Stavert, Lynn; Burk, Thomas; Beach, David; Signorelli, Joel; Jones, Jeremy; Hahn, Yungsun; Attiyah, Ahlam; Illsley, Jeannette

    2009-01-01

    The Maneuver Automation Software (MAS) automates the process of generating commands for maneuvers to keep the spacecraft of the Cassini-Huygens mission on a predetermined prime mission trajectory. Before MAS became available, a team of approximately 10 members had to work about two weeks to design, test, and implement each maneuver in a process that involved running many maneuver-related application programs and then serially handing off data products to other parts of the team. MAS enables a three-member team to design, test, and implement a maneuver in about one-half hour after Navigation has process-tracking data. MAS accepts more than 60 parameters and 22 files as input directly from users. MAS consists of Practical Extraction and Reporting Language (PERL) scripts that link, sequence, and execute the maneuver- related application programs: "Pushing a single button" on a graphical user interface causes MAS to run navigation programs that design a maneuver; programs that create sequences of commands to execute the maneuver on the spacecraft; and a program that generates predictions about maneuver performance and generates reports and other files that enable users to quickly review and verify the maneuver design. MAS can also generate presentation materials, initiate electronic command request forms, and archive all data products for future reference.

  16. Ischemic preconditioning increases muscle perfusion, oxygen uptake, and force in strength-trained athletes.

    PubMed

    Paradis-Deschênes, Pénélope; Joanisse, Denis R; Billaut, François

    2016-09-01

    Muscle ischemia and reperfusion induced by ischemic preconditioning (IPC) can improve performance in various activities. However, the underlying mechanisms are still poorly understood. The purpose of this study was to examine the effects of IPC on muscle hemodynamics and oxygen (O2) uptake during repeated maximal contractions. In a cross-over, randomized, single-blind study, 10 strength-trained men performed 5 sets of 5 maximal voluntary knee extensions of the right leg on an isokinetic dynamometer, preceded by either IPC of the right lower limb (3×5-min compression/5-min reperfusion cycles at 200 mm Hg) or sham (20 mm Hg). Changes in deoxyhemoglobin, expressed as a percentage of arterial occlusion, and total hemoglobin ([THb]) concentrations of the vastus lateralis muscle were monitored continuously by near-infrared spectroscopy. Differences between IPC and sham were analyzed using Cohen's effect size (ES) ± 90% confidence limits, and magnitude-based inferences. Compared with sham, IPC likely increased muscle blood volume at rest (↑[THb], 46.5%; ES, 0.56; 90% confidence limits for ES, -0.21, 1.32). During exercise, peak force was almost certainly higher (11.8%; ES, 0.37; 0.27, 0.47), average force was very likely higher (12.6%; ES, 0.47; 0.29, 0.66), and average muscle O2 uptake was possibly increased (15.8%; ES, 0.36; -0.07, 0.79) after IPC. In the recovery periods between contractions, IPC also increased blood volume after sets 1 (23.6%; ES, 0.30; -0.05, 0.65) and 5 (25.1%; ES, 0.32; 0.09, 0.55). Three cycles of IPC immediately increased muscle perfusion and O2 uptake, conducive to higher repeated force capacity in strength-trained athletes. This maneuver therefore appears relevant to enhancing exercise training stimulus. PMID:27574913

  17. Renal transplantation induces mitochondrial uncoupling, increased kidney oxygen consumption, and decreased kidney oxygen tension.

    PubMed

    Papazova, Diana A; Friederich-Persson, Malou; Joles, Jaap A; Verhaar, Marianne C

    2015-01-01

    Hypoxia is an acknowledged pathway to renal injury and ischemia-reperfusion (I/R) and is known to reduce renal oxygen tension (Po2). We hypothesized that renal I/R increases oxidative damage and induces mitochondrial uncoupling, resulting in increased oxygen consumption and hence kidney hypoxia. Lewis rats underwent syngenic renal transplantation (TX) and contralateral nephrectomy. Controls were uninephrectomized (1K-CON) or left untreated (2K-CON). After 7 days, urinary excretion of protein and thiobarbituric acid-reactive substances were measured, and after 14 days glomerular filtration rate (GFR), renal blood flow, whole kidney Qo2, cortical Po2, kidney cortex mitochondrial uncoupling, renal oxidative damage, and tubulointerstitial injury were assessed. TX, compared with 1K-CON, resulted in mitochondrial uncoupling mediated via uncoupling protein-2 (16 ± 3.3 vs. 0.9 ± 0.4 pmol O2 · s(-1)· mg protein(-1), P < 0.05) and increased whole kidney Qo2 (55 ± 16 vs. 33 ± 10 μmol O2/min, P < 0.05). Corticomedullary Po2 was lower in TX compared with 1K-CON (30 ± 13 vs. 47 ± 4 μM, P < 0.05) whereas no significant difference was observed between 2K-CON and 1K-CON rats. Proteinuria, oxidative damage, and the tubulointerstitial injury score were not significantly different in 1K-CON and TX. Treatment of donors for 5 days with mito-TEMPO reduced mitochondrial uncoupling but did not affect renal hemodynamics, Qo2, Po2, or injury. Collectively, our results demonstrate increased mitochondrial uncoupling as an early event after experimental renal transplantation associated with increased oxygen consumption and kidney hypoxia in the absence of increases in markers of damage.

  18. Increased cerebral oxygenation precedes generalized tonic clonic seizures.

    PubMed

    Moseley, Brian D; Britton, Jeffrey W; So, Elson

    2014-11-01

    Based on previous fMRI and SPECT studies, it has been suggested seizures may be preceded by increased cerebral blood flow. Recently, we demonstrated transcutaneous regional cerebral oxygen saturation (rSO2) sensors are feasible for use in patients undergoing video EEG monitoring. We reanalyzed our data to determine if seizures were consistently marked by increased cerebral oxygenation. Patients with histories of generalized tonic clonic seizures (GTCS) were recruited into our study. All subjects were evaluated with continuous 30-channel scalp EEG and 2 rSO2 sensors placed on each side of the forehead. We calculated the mean rSO2 value for the 1h epochs in the non-ictal (2h prior to seizure onset) and pre-ictal (1h prior to onset) periods. Seven primary/secondarily GTCS from 5 patients were captured. The mean rSO2 value in the non-ictal period was 75.6 ± 5.7%. This increased to 76.0 ± 6% in the pre-ictal period (p=0.032). Four of the 7GTCS (57.1%) were marked by ≥ 3 sequential rSO2 values in the pre-ictal period that were ≥ 3 SDs greater than the mean non-ictal rSO2 value. Three GTCS (42.9%) were marked by sustained cerebral hyperemia for ≥ 15 consecutive readings. Our results suggest increased cerebral blood flow could be non-invasively used to predict seizure occurrence. PMID:25277885

  19. Oxygen intrusion into anoxic fjords leads to increased methylmercury availability

    NASA Astrophysics Data System (ADS)

    Veiteberg Braaten, Hans Fredrik; Pakhomova, Svetlana; Yakushev, Evgeniy

    2013-04-01

    Mercury (Hg) appears in the oxic surface waters of the oceans at low levels (sub ng/L). Because inorganic Hg can be methylated into the toxic and bioaccumulative specie methylmercury (MeHg) levels can be high at the top of the marine food chain. Even though marine sea food is considered the main risk driver for MeHg exposure to people most research up to date has focused on Hg methylation processes in freshwater systems. This study identifies the mechanisms driving formation of MeHg during oxygen depletion in fjords, and shows how MeHg is made available in the surface water during oxygen intrusion. Studies of the biogeochemical structure in the water column of the Norwegian fjord Hunnbunn were performed in 2009, 2011 and 2012. In autumn of 2011 mixing flushing events were observed and lead to both positive and negative effects on the ecosystem state in the fjord. The oxygenated water intrusions lead to a decrease of the deep layer concentrations of hydrogen sulfide (H2S), ammonia and phosphate. On the other hand the intrusion also raised the H2S boundary from 8 m to a shallower depth of just 4 m. Following the intrusion was also observed an increase at shallower depths of nutrients combined with a decrease of pH. Before flushing events were observed concentrations of total Hg (TotHg) increased from 1.3 - 1.7 ng/L in the surface layer of the fjord to concentrations ranging from 5.2 ng/L to 6.4 ng/L in the anoxic zone. MeHg increased regularly from 0.04 ng/L in the surface water to a maximum concentration of 5.2 ng/L in the deeper layers. This corresponds to an amount of TotHg present as MeHg ranging from 2.1 % to 99 %. The higher concentrations of MeHg in the deeper layer corresponds to an area where no oxygen is present and concentrations of H2S exceeds 500 µM, suggesting a production of MeHg in the anoxic area as a result of sulphate reducing bacteria activity. After flushing the concentrations of TotHg showed a similar pattern ranging from 0.6 ng/L in the

  20. Endophytic Bacterium-Triggered Reactive Oxygen Species Directly Increase Oxygenous Sesquiterpenoid Content and Diversity in Atractylodes lancea

    PubMed Central

    Zhou, Jia-Yu; Yuan, Jie; Li, Xia; Ning, Yi-Fan

    2015-01-01

    Oxygenous terpenoids are active components of many medicinal plants. However, current studies that have focused on enzymatic oxidation reactions cannot comprehensively clarify the mechanisms of oxygenous terpenoid synthesis and diversity. This study shows that an endophytic bacterium can trigger the generation of reactive oxygen species (ROS) that directly increase oxygenous sesquiterpenoid content and diversity in Atractylodes lancea. A. lancea is a famous but endangered Chinese medicinal plant that contains abundant oxygenous sesquiterpenoids. Geo-authentic A. lancea produces a wider range and a greater abundance of oxygenous sesquiterpenoids than the cultivated herb. Our previous studies have shown the mechanisms behind endophytic promotion of the production of sesquiterpenoid hydrocarbon scaffolds; however, how endophytes promote the formation of oxygenous sesquiterpenoids and their diversity is unclear. After colonization by Pseudomonas fluorescens ALEB7B, oxidative burst and oxygenous sesquiterpenoid accumulation in A. lancea occur synchronously. Treatment with exogenous hydrogen peroxide (H2O2) or singlet oxygen induces oxidative burst and promotes oxygenous sesquiterpenoid accumulation in planta. Conversely, pretreatment of plantlets with the ROS scavenger ascorbic acid significantly inhibits the oxidative burst and oxygenous sesquiterpenoid accumulation induced by P. fluorescens ALEB7B. Further in vitro oxidation experiments show that several oxygenous sesquiterpenoids can be obtained from direct oxidation caused by H2O2 or singlet oxygen. In summary, this study demonstrates that endophytic bacterium-triggered ROS can directly oxidize oxygen-free sesquiterpenoids and increase the oxygenous sesquiterpenoid content and diversity in A. lancea, providing a novel explanation of the mechanisms of oxygenous terpenoid synthesis in planta and an essential complementarity to enzymatic oxidation reactions. PMID:26712554

  1. Novel vagal maneuver technique for termination of supraventricular tachycardias.

    PubMed

    Un, Haluk; Dogan, Mehmet; Uz, Omer; Isilak, Zafer; Uzun, Mehmet

    2016-01-01

    Hemodynamically unstable patients with supraventricular tachycardias (SVTs) should be treated with electrical cardioversion. If the patient is stable, acute termination of tachycardia can be achieved by vagal maneuvers or medical therapy. The Valsalva maneuver, carotid massage, and ice to the face are the most common vagal maneuvers. In our experience with patients, we observed that vagal stimulation increases with lying backward. Our suggested maneuver is based on quickly lying backward, from a seated position. Then, a short and powerful vagal stimulation occurs. Thus, SVT episodes can be terminated. Here we present our experience of a new maneuver for terminating SVT, with cases.

  2. Vibration Characteristics of Squeeze Film Damper during Maneuver Flight

    NASA Astrophysics Data System (ADS)

    Wang, Siji; Liao, Mingfu; Li, Wei

    2015-05-01

    The rotor systems of an aero engine will endure additional centrifugal force and gyroscopic moment during maneuver flight. A maneuver fly mechanical simulator is designed and experimental investigations on dynamics of squeeze film damper (SFD) under the different additional centrifugal force and gyroscopic moment are carried out. The results show that the maneuver flight weaken effectiveness of the SFD, the additional centrifugal force and gyroscopic moment caused by maneuver flight will change film damping, film stiffness. And the influence of maneuver flight can be effective relieved by increasing the film clearance.

  3. Polymer etching in the oxygen afterglow - Increased etch rates with increased reactor loading

    NASA Technical Reports Server (NTRS)

    Lerner, N. R.; Wydeven, T.

    1989-01-01

    Reactor loading has an effect on the etch rate (rate of decrease of film thickness) of films of polyvinylfluoride (Tedlar) and polyethylene exposed in the afterglow of an RF discharge in oxygen. The etch rate is found to increase with the total surface area of the polymer exposed in the reactor. The etch rates of polypyromellitimide (Kapton H) and polystyrene under these conditions are very low. However, the etch rate of these polymers is greatly enhanced by adding either Tedlar or polyethylene to the reactor. A kinetic model is proposed based on the premise that the oxygen atoms produced by the RF discharge react with Tedlar or polyethylene to produce a much more reactive species, which dominates the etching of the polymers studied.

  4. Alveolar recruitment maneuvers: are your patients missing out?

    PubMed

    Hartland, Benjamin L; Newell, Timothy J; Damico, Nicole

    2014-08-01

    Awake, spontaneously breathing humans sigh on average 9 to 10 times per hour. The sigh is a normal homeostatic reflex proposed to maintain pulmonary compliance and decrease the formation of atelectasis by recruiting collapsed alveoli. The induction and maintenance of anesthesia with muscle paralysis and a fixed tidal volume abolish the sigh. Without periodic sighs, patients are left susceptible to atelectasis and its negative sequelae. The prevalence of atelectasis has been estimated to be as high as 100% in patients undergoing general anesthesia. A strong correlation between atelectasis and postoperative pulmonary complications has been demonstrated. Postoperative pulmonary complications lengthen hospital stays and increase healthcare costs. Alveolar recruitment maneuvers, which make up one component of open lung ventilation, have been described as vital capacity breaths, double tidal volume breaths, and sigh breaths. These simple maneuvers result in a sustained increase in airway pressure that serves to recruit collapsed alveoli and improve arterial oxygenation. This article examines the literature regarding the application of alveolar recruitment maneuvers in the perioperative setting. The format is a series of clinically oriented questions posed to help the reader translate available evidence into practice.

  5. Can we increase hepatic oxygen availability? The role of intentional hypercarbia.

    PubMed

    Atallah, M M; Demian, A D; el-Diasty, T A; Ma Saied, M

    2000-06-01

    Our hypothesis is that hypercarbia produces sympathetic stimulant effect and local vasodilatation. We studied the effect of intentional hypercarbia (IHC) on hepatic venous oxygen saturation. The hepatic vein (HV) was cannulated in 15 patients through either the right internal jugular vein or the femoral vein to measure HV oxygen saturation and calculate oxygen content. The inferior vena cava (IVC) was cannulated in 6 patients above and below drainage of the hepatic veins for oxygen saturation and content difference along the IVC. IHC was achieved in awake patients by breathing oxygen enriched air at a flow rate of 2L/min for 10 min, and during anesthesia by increasing anesthetic dead space and reducing tidal volume. IHC increased HV blood oxygen saturation, decreased the arterio-hepatic vein oxygen content difference and decreased oxygen saturation difference and oxygen content difference along IVC. PMID:11126503

  6. Increase in whole-body peripheral vascular resistance during three hours of air or oxygen prebreathing

    NASA Technical Reports Server (NTRS)

    Waligora, J. M.; Horrigan, D. J., Jr.; Conkin, J.; Dierlam, J. J.; Stanford, J., Jr.; Riddle, J. R.

    1984-01-01

    Male and female subjects prebreathed air or 100% oxygen through a mask for 3.0 hours while comfortably reclined. Blood pressures, heart rate, and cardiac output were collected before and after the prebreathe. Peripheral vascular resistance (PVR) was calculated from these parameters and increased by 29% during oxygen prebreathing and 15% during air prebreathing. The oxygen contributed substantially to the increase in PVR. Diastolic blood pressure increased by 18% during the oxygen prebreathe while stystolic blood pressure showed no change under either procedure. The increase in PVR during air prebreathing was attributed to procedural stress common to air and oxygen prebreathing.

  7. Cerebral hemodynamics during graded Valsalva maneuvers

    PubMed Central

    Perry, Blake G.; Cotter, James D.; Mejuto, Gaizka; Mündel, Toby; Lucas, Samuel J. E.

    2014-01-01

    The Valsalva maneuver (VM) produces large and abrupt changes in mean arterial pressure (MAP) that challenge cerebral blood flow and oxygenation. We examined the effect of VM intensity on middle cerebral artery blood velocity (MCAv) and cortical oxygenation responses during (phases I–III) and following (phase IV) a VM. Healthy participants (n = 20 mean ± SD: 27 ± 7 years) completed 30 and 90% of their maximal VM mouth pressure for 10 s (order randomized) whilst standing. Beat-to-beat MCAv, cerebral oxygenation (NIRS) and MAP across the different phases of the VM are reported as the difference from standing baseline. There were significant interaction (phase * intensity) effects for MCAv, total oxygenation index (TOI) and MAP (all P < 0.01). MCAv decreased during phases II and III (P < 0.01), with the greatest decrease during phase III (−5 ± 8 and −19 ± 15 cm·s−1 for 30 and 90% VM, respectively). This pattern was also evident in TOI (phase III: −1 ± 1 and −5 ± 4%, both P < 0.05). Phase IV increased MCAv (22 ± 15 and 34 ± 23 cm·s−1), MAP (15 ± 14 and 24 ± 17 mm Hg) and TOI (5 ± 6 and 7 ± 5%) relative to baseline (all P < 0.05). Cerebral autoregulation, indexed, as the %MCAv/%MAP ratio, showed a phase effect only (P < 0.001), with the least regulation during phase IV (2.4 ± 3.0 and 3.2 ± 2.9). These data illustrate that an intense VM profoundly affects cerebral hemodynamics, with a reactive hyperemia occurring during phase IV following modest ischemia during phases II and III. PMID:25309449

  8. Cathodo- and photoluminescence increase in amorphous hafnium oxide under annealing in oxygen

    SciTech Connect

    Ivanova, E. V. Zamoryanskaya, M. V.; Pustovarov, V. A.; Aliev, V. Sh.; Gritsenko, V. A.; Yelisseyev, A. P.

    2015-04-15

    Cathodo- and photoluminescence of amorphous nonstoichiometric films of hafnium oxide are studied with the aim to verify the hypothesis that oxygen vacancies are responsible for the luminescence. To produce oxygen vacancies, hafnium oxide was enriched in surplus metal during synthesis. To reduce the oxygen concentration, the film was annealed in oxygen. A qualitative control of the oxygen concentration was carried out by the refractive index. In the initial, almost stoichiometric films we observed a 2.7-eV band in cathodoluminescence. Annealing in oxygen results in a considerable increase in its intensity, as well as in the appearance of new bands at 1.87, 2.14, 3.40, and 3.6 eV. The observed emission bands are supposed to be due to single oxygen vacancies and polyvacancies in hafnium oxide. The luminescence increase under annealing in an oxygen atmosphere may be a result of the emission quenching effect.

  9. Direct lateral maneuvers in hawkmoths.

    PubMed

    Greeter, Jeremy S M; Hedrick, Tyson L

    2016-01-01

    We used videography to investigate direct lateral maneuvers, i.e. 'sideslips', of the hawkmoth Manduca sexta. M. sexta sideslip by rolling their entire body and wings to reorient their net force vector. During sideslip they increase net aerodynamic force by flapping with greater amplitude, (in both wing elevation and sweep), allowing them to continue to support body weight while rolled. To execute the roll maneuver we observed in sideslips, they use an asymmetric wing stroke; increasing the pitch of the roll-contralateral wing pair, while decreasing that of the roll-ipsilateral pair. They also increase the wing sweep amplitude of, and decrease the elevation amplitude of, the contralateral wing pair relative to the ipsilateral pair. The roll maneuver unfolds in a stairstep manner, with orientation changing more during downstroke than upstroke. This is due to smaller upstroke wing pitch angle asymmetries as well as increased upstroke flapping counter-torque from left-right differences in global reference frame wing velocity about the moth's roll axis. Rolls are also opposed by stabilizing aerodynamic moments from lateral motion, such that rightward roll velocity will be opposed by rightward motion. Computational modeling using blade-element approaches confirm the plausibility of a causal linkage between the previously mentioned wing kinematics and roll/sideslip. Model results also predict high degrees of axial and lateral damping. On the time scale of whole and half wing strokes, left-right wing pair asymmetries directly relate to the first, but not second, derivative of roll. Collectively, these results strongly support a roll-based sideslip with a high degree of roll damping in M. sexta. PMID:26740573

  10. Direct lateral maneuvers in hawkmoths

    PubMed Central

    Greeter, Jeremy S. M.; Hedrick, Tyson L.

    2016-01-01

    ABSTRACT We used videography to investigate direct lateral maneuvers, i.e. ‘sideslips’, of the hawkmoth Manduca sexta. M. sexta sideslip by rolling their entire body and wings to reorient their net force vector. During sideslip they increase net aerodynamic force by flapping with greater amplitude, (in both wing elevation and sweep), allowing them to continue to support body weight while rolled. To execute the roll maneuver we observed in sideslips, they use an asymmetric wing stroke; increasing the pitch of the roll-contralateral wing pair, while decreasing that of the roll-ipsilateral pair. They also increase the wing sweep amplitude of, and decrease the elevation amplitude of, the contralateral wing pair relative to the ipsilateral pair. The roll maneuver unfolds in a stairstep manner, with orientation changing more during downstroke than upstroke. This is due to smaller upstroke wing pitch angle asymmetries as well as increased upstroke flapping counter-torque from left-right differences in global reference frame wing velocity about the moth's roll axis. Rolls are also opposed by stabilizing aerodynamic moments from lateral motion, such that rightward roll velocity will be opposed by rightward motion. Computational modeling using blade-element approaches confirm the plausibility of a causal linkage between the previously mentioned wing kinematics and roll/sideslip. Model results also predict high degrees of axial and lateral damping. On the time scale of whole and half wing strokes, left-right wing pair asymmetries directly relate to the first, but not second, derivative of roll. Collectively, these results strongly support a roll-based sideslip with a high degree of roll damping in M. sexta. PMID:26740573

  11. Direct lateral maneuvers in hawkmoths.

    PubMed

    Greeter, Jeremy S M; Hedrick, Tyson L

    2016-01-01

    We used videography to investigate direct lateral maneuvers, i.e. 'sideslips', of the hawkmoth Manduca sexta. M. sexta sideslip by rolling their entire body and wings to reorient their net force vector. During sideslip they increase net aerodynamic force by flapping with greater amplitude, (in both wing elevation and sweep), allowing them to continue to support body weight while rolled. To execute the roll maneuver we observed in sideslips, they use an asymmetric wing stroke; increasing the pitch of the roll-contralateral wing pair, while decreasing that of the roll-ipsilateral pair. They also increase the wing sweep amplitude of, and decrease the elevation amplitude of, the contralateral wing pair relative to the ipsilateral pair. The roll maneuver unfolds in a stairstep manner, with orientation changing more during downstroke than upstroke. This is due to smaller upstroke wing pitch angle asymmetries as well as increased upstroke flapping counter-torque from left-right differences in global reference frame wing velocity about the moth's roll axis. Rolls are also opposed by stabilizing aerodynamic moments from lateral motion, such that rightward roll velocity will be opposed by rightward motion. Computational modeling using blade-element approaches confirm the plausibility of a causal linkage between the previously mentioned wing kinematics and roll/sideslip. Model results also predict high degrees of axial and lateral damping. On the time scale of whole and half wing strokes, left-right wing pair asymmetries directly relate to the first, but not second, derivative of roll. Collectively, these results strongly support a roll-based sideslip with a high degree of roll damping in M. sexta.

  12. Close approach maneuvers around an oblate planet

    NASA Astrophysics Data System (ADS)

    Oliveira, G. M. C.; Prado, A. F. B. A.; Sanchez, D. M.

    2015-10-01

    There are many applications of the close approach maneuvers in astronautics, and several missions used this technique in the last decades. In the present work, those close approach maneuvers are revisited, but now considering that the spacecraft passes around an oblate planet. This fact changes the distribution of mass of the planet, increasing the mass in the region of the equator, so increasing the gravitational forces in the equatorial plane. Since the present study is limited to planar trajectories, there is an increase in the variation of energy given by the maneuver. The planet Jupiter is used as the body for the close approach, but the value of J2 is varied in a large range to simulate situations of other celestial bodies that have larger oblateness, but the same mass ratio. This is particularly true in recent discovered exoplanets, and this first study can help the study of the dynamics around those bodies.

  13. Surface energy increase of oxygen-plasma-treated PET

    SciTech Connect

    Cioffi, M.O.H.; Voorwald, H.J.C.; Mota, R.P

    2003-03-15

    Prosthetic composite is a widely used biomaterial that satisfies the criteria for application as an organic implant without adverse reactions. Polyethylene therephthalate (PET) fiber-reinforced composites have been used because of the excellent cell adhesion, biodegradability and biocompatibility. The chemical inertness and low surface energy of PET in general are associated with inadequate bonds for polymer reinforcements. It is recognized that the high strength of composites, which results from the interaction between the constituents, is directly related to the interfacial condition or to the interphase. A radio frequency plasma reactor using oxygen was used to treat PET fibers for 5, 20, 30 and 100 s. The treatment conditions were 13.56 MHz, 50 W, 40 Pa and 3.33x10{sup -7} m{sup 3}/s. A Rame-Hart goniometer was used to measure the contact angle and surface energy variation of fibers treated for different times. The experimental results showed contact angle values from 47 deg. to 13 deg. and surface energies from 6.4x10{sup -6} to 8.3x10{sup -6} J for the range of 5 to 100 s, respectively. These results were confirmed by the average ultimate tensile strength of the PET fiber/ polymethylmethacrylate (PMMA) matrix composite tested in tensile mode and by scanning electron microscopy.

  14. Breathing Maneuvers as a Vasoactive Stimulus for Detecting Inducible Myocardial Ischemia – An Experimental Cardiovascular Magnetic Resonance Study

    PubMed Central

    Fischer, Kady; Guensch, Dominik P; Shie, Nancy; Lebel, Julie; Friedrich, Matthias G

    2016-01-01

    Background Breathing maneuvers can elicit a similar vascular response as vasodilatory agents like adenosine; yet, their potential diagnostic utility in the presence of coronary artery stenosis is unknown. The objective of the study is to investigate if breathing maneuvers can non-invasively detect inducible ischemia in an experimental animal model when the myocardium is imaged with oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR). Methods and Findings In 11 anesthetised swine with experimentally induced significant stenosis (fractional flow reserve <0.75) of the left anterior descending coronary artery (LAD) and 9 control animals, OS-CMR at 3T was performed during two different breathing maneuvers, a long breath-hold; and a combined maneuver of 60s of hyperventilation followed by a long breath-hold. The resulting change of myocardial oxygenation was compared to the invasive measurements of coronary blood flow, blood gases, and oxygen extraction. In control animals, all breathing maneuvers could significantly alter coronary blood flow as hyperventilation decreased coronary blood flow by 34±23%. A long breath-hold alone led to an increase of 97±88%, while the increase was 346±327% (p<0.001), when the long breath-hold was performed after hyperventilation. In stenosis animals, the coronary blood flow response was attenuated after both hyperventilation and the following breath-hold. This was matched by the observed oxygenation response as breath-holds following hyperventilation consistently yielded a significant difference in the signal of the MRI images between the perfusion territory of the stenosis LAD and remote myocardium. There was no difference between the coronary territories during the other breathing maneuvers or in the control group at any point. Conclusion In an experimental animal model, the response to a combined breathing maneuver of hyperventilation with subsequent breath-holding is blunted in myocardium subject to significant coronary

  15. Adaptive formation flying maneuvers for multiple relative orbits

    NASA Astrophysics Data System (ADS)

    Saunders, Marc

    In order to extend and preserve the mission of an earth orbiting satellite it is imperative that the on board maneuvers do not waste propulsion but maneuver the spacecraft optimally. The challenge for ground stations is to plan maneuvers for spacecraft that will achieve a desired orbit while minimizing fuel costs. Increasing this challenge is the addition of specific keep-out zones (constraints on the spacecraft). For example, a low-earth orbiter (LEO) may need to maintain a specific orbit plane for a sun-synchronous imaging mission but it now has to contend with opposing debris. Computing a maneuver to avoid the debris could have consequences to the mission constraints and cause undesired affects to the desired orbit. The purpose of this research is to develop some techniques that can aid in finding some optimal maneuvers (or maneuvers that use the least amount of energy) and will maintain mission requirements while preserving constraints. Two different models will be developed that can minimize energy used in the maneuvers. The first model is a linear set of impulsive maneuvers derived from the Clohessy-Wilshire Equations. This model can be used as a targeting equation for targeting a specific relative orbit that also minimizes the total energy among a series of maneuvers. The second method is a nonlinear model using a Lyapunov Function in a feedback control loop; where the position of a spacecraft relative to a target orbit is minimized and the reference motion can be used to create keep-out zones.

  16. Grunting in tennis increases ball velocity but not oxygen cost.

    PubMed

    Callison, Emily R; Berg, Kris E; Slivka, Dusting R

    2014-07-01

    Grunting is widely used by professional tennis players, but no research has been done to verify enhanced performance with grunting. Therefore, the purpose of this study was to determine if grunting enhanced ball velocity in groundstrokes and secondly, to determine if grunting increased the physiological cost of hitting (VO2, HR, VE/VO2, and RPE). Participants were 10 members of the men's (n = 5) and women's (n = 5) tennis teams at a Division I university who had just completed their indoor competitive season. Two hitting sessions were used as players repetitively hit forehand and backhand shots while either grunting or not grunting. Each hitting session consisted of five 2-minute periods with a 1-minute break in between each period. Ball velocity was measured with a radar gun. During each hitting session, players wore a portable metabolic measuring unit. HR was monitored using a Polar monitor, and RPE was assessed using Borg's 6-20 scale. Grunting increased ball velocity (kph) 3.8% compared with non-grunting condition (p < 0.034) with the mean ± SD being 83.4 ± 0.6.1 and 80.3 ± 0.8.7, respectively. The physiological responses (VO2, HR, VE/VO2, and RPE) for the 2 hitting conditions were not significantly different for any variable. When averaged across both hitting conditions, HR over the 5-time periods was higher in periods 3-5 than period (p < 0.018) 1, whereas VE/VO2 and RPE were greater in periods 2-5 than period 1 (p = 0.001). RPE significantly increased over time with periods 2-5 being greater than period 1 (p = 0.001). It was concluded that grunting increased ball velocity without increasing VO2 or VE/VO2 or RPE in comparison with not grunting. It may be worthwhile for players and coaches in tennis and other sports to experiment with grunting to determine possible improvement in performance.

  17. Laparoscopic Pringle maneuver: how we do it?

    PubMed Central

    Lhuaire, Martin; Memeo, Riccardo; Pessaux, Patrick; Kianmanesh, Reza; Sommacale, Daniele

    2016-01-01

    Laparoscopic liver resection (LLR) is technically possible with new devices which allow a relatively bloodless liver parenchymal transection. Despite, the main concern remains intraoperative hemorrhage. Currently, perioperative excessive blood loss during LLR is difficult to control with necessity of laparotomy conversion. Moreover, major blood loss requires transfusion and increases postoperative morbidity and mortality. When in-flow is limited by the hepatic pedicle clamping, it reduces intraoperative blood loss. The Pringle maneuver, first described in 1908, is the simplest method of inflow occlusion and currently can be achieved during LLR. The purpose of this note was to describe two different modalities of Pringle maneuver used by two different teams during LLR. PMID:27500146

  18. General and Specific Strategies Used to Facilitate Locomotor Maneuvers

    PubMed Central

    Wu, Mengnan; Matsubara, Jesse H.; Gordon, Keith E.

    2015-01-01

    People make anticipatory changes in gait patterns prior to initiating a rapid change of direction. How they prepare will change based on their knowledge of the maneuver. To investigate specific and general strategies used to facilitate locomotor maneuvers, we manipulated subjects’ ability to anticipate the direction of an upcoming lateral “lane-change” maneuver. To examine specific anticipatory adjustments, we observed the four steps immediately preceding a maneuver that subjects were instructed to perform at a known time in a known direction. We hypothesized that to facilitate a specific change of direction, subjects would proactively decrease margin of stability in the future direction of travel. Our results support this hypothesis: subjects significantly decreased lateral margin of stability by 69% on the side ipsilateral to the maneuver during only the step immediately preceding the maneuver. This gait adaptation may have improved energetic efficiency and simplified the control of the maneuver. To examine general anticipatory adjustments, we observed the two steps immediately preceding the instant when subjects received information about the direction of the maneuver. When the maneuver direction was unknown, we hypothesized that subjects would make general anticipatory adjustments that would improve their ability to actively initiate a maneuver in multiple directions. This second hypothesis was partially supported as subjects increased step width and stance phase hip flexion during these anticipatory steps. These modifications may have improved subjects’ ability to generate forces in multiple directions and maintain equilibrium during the onset and execution of the rapid maneuver. However, adapting these general anticipatory strategies likely incurred an additional energetic cost. PMID:26167931

  19. Reducing Formation-Keeping Maneuver Costs for Formation Flying Satellites in Low-Earth Orbit

    NASA Technical Reports Server (NTRS)

    Hamilton, Nicholas

    2001-01-01

    Several techniques are used to synthesize the formation-keeping control law for a three-satellite formation in low-earth orbit. The objective is to minimize maneuver cost and position tracking error. Initial reductions are found for a one-satellite case by tuning the state-weighting matrix within the linear-quadratic-Gaussian framework. Further savings come from adjusting the maneuver interval. Scenarios examined include cases with and without process noise. These results are then applied to a three-satellite formation. For both the one-satellite and three-satellite cases, increasing the maneuver interval yields a decrease in maneuver cost and an increase in position tracking error. A maneuver interval of 8-10 minutes provides a good trade-off between maneuver cost and position tracking error. An analysis of the closed-loop poles with respect to varying maneuver intervals explains the effectiveness of the chosen maneuver interval.

  20. Higher respiratory activity decreases mitochondrial reactive oxygen release and increases life span in Saccharomyces cerevisiae.

    PubMed

    Barros, Mario H; Bandy, Brian; Tahara, Erich B; Kowaltowski, Alicia J

    2004-11-26

    Increased replicative longevity in Saccharomyces cerevisiae because of calorie restriction has been linked to enhanced mitochondrial respiratory activity. Here we have further investigated how mitochondrial respiration affects yeast life span. We found that calorie restriction by growth in low glucose increased respiration but decreased mitochondrial reactive oxygen species production relative to oxygen consumption. Calorie restriction also enhanced chronological life span. The beneficial effects of calorie restriction on mitochondrial respiration, reactive oxygen species release, and replicative and chronological life span could be mimicked by uncoupling agents such as dinitrophenol. Conversely, chronological life span decreased in cells treated with antimycin (which strongly increases mitochondrial reactive oxygen species generation) or in yeast mutants null for mitochondrial superoxide dismutase (which removes superoxide radicals) and for RTG2 (which participates in retrograde feedback signaling between mitochondria and the nucleus). These results suggest that yeast aging is linked to changes in mitochondrial metabolism and oxidative stress and that mild mitochondrial uncoupling can increase both chronological and replicative life span.

  1. Use of Atomic Oxygen for Increased Water Contact Angles of Various Polymers for Biomedical Applications

    NASA Technical Reports Server (NTRS)

    Beger, Lauren; Roberts, Lily; deGroh, Kim; Banks, Bruce

    2007-01-01

    In the low Earth orbit (LEO) space environment, spacecraft surfaces can be altered during atomic oxygen exposure through oxidation and erosion. There can be terrestrial benefits of such interactions, such as the modification of hydrophobic or hydrophilic properties of polymers due to chemical modification and texturing. Such modification of the surface may be useful for biomedical applications. For example, atomic oxygen texturing may increase the hydrophilicity of polymers, such as chlorotrifluoroethylene (Aclar), thus allowing increased adhesion and spreading of cells on textured Petri dishes. The purpose of this study was to determine the effect of atomic oxygen exposure on the hydrophilicity of nine different polymers. To determine whether hydrophilicity remains static after atomic oxygen exposure or changes with exposure, the contact angles between the polymer and a water droplet placed on the polymer s surface were measured. The polymers were exposed to atomic oxygen in a radio frequency (RF) plasma asher. Atomic oxygen plasma treatment was found to significantly alter the hydrophilicity of non-fluorinated polymers. Significant decreases in the water contact angle occurred with atomic oxygen exposure. Fluorinated polymers were found to be less sensitive to changes in hydrophilicity for equivalent atomic oxygen exposures, and two of the fluorinated polymers became more hydrophobic. The majority of change in water contact angle of the non-fluorinated polymers was found to occur with very low fluence exposures, indicating potential cell culturing benefit with short treatment time.

  2. Dynamic Tow Maneuver Orbital Launch Technique

    NASA Technical Reports Server (NTRS)

    Rutan, Elbert L. (Inventor)

    2014-01-01

    An orbital launch system and its method of operation use a maneuver to improve the launch condition of a booster rocket and payload. A towed launch aircraft, to which the booster rocket is mounted, is towed to a predetermined elevation and airspeed. The towed launch aircraft begins the maneuver by increasing its lift, thereby increasing the flight path angle, which increases the tension on the towline connecting the towed launch aircraft to a towing aircraft. The increased tension accelerates the towed launch aircraft and booster rocket, while decreasing the speed (and thus the kinetic energy) of the towing aircraft, while increasing kinetic energy of the towed launch aircraft and booster rocket by transferring energy from the towing aircraft. The potential energy of the towed launch aircraft and booster rocket is also increased, due to the increased lift. The booster rocket is released and ignited, completing the launch.

  3. Liquid films on shake flask walls explain increasing maximum oxygen transfer capacities with elevating viscosity.

    PubMed

    Giese, Heiner; Azizan, Amizon; Kümmel, Anne; Liao, Anping; Peter, Cyril P; Fonseca, João A; Hermann, Robert; Duarte, Tiago M; Büchs, Jochen

    2014-02-01

    In biotechnological screening and production, oxygen supply is a crucial parameter. Even though oxygen transfer is well documented for viscous cultivations in stirred tanks, little is known about the gas/liquid oxygen transfer in shake flask cultures that become increasingly viscous during cultivation. Especially the oxygen transfer into the liquid film, adhering on the shake flask wall, has not yet been described for such cultivations. In this study, the oxygen transfer of chemical and microbial model experiments was measured and the suitability of the widely applied film theory of Higbie was studied. With numerical simulations of Fick's law of diffusion, it was demonstrated that Higbie's film theory does not apply for cultivations which occur at viscosities up to 10 mPa s. For the first time, it was experimentally shown that the maximum oxygen transfer capacity OTRmax increases in shake flasks when viscosity is increased from 1 to 10 mPa s, leading to an improved oxygen supply for microorganisms. Additionally, the OTRmax does not significantly undermatch the OTRmax at waterlike viscosities, even at elevated viscosities of up to 80 mPa s. In this range, a shake flask is a somehow self-regulating system with respect to oxygen supply. This is in contrary to stirred tanks, where the oxygen supply is steadily reduced to only 5% at 80 mPa s. Since, the liquid film formation at shake flask walls inherently promotes the oxygen supply at moderate and at elevated viscosities, these results have significant implications for scale-up.

  4. Support and maneuvering device

    DOEpatents

    Wood, Richard L.

    1988-01-01

    A support and maneuvering device includes an elongated flexible inflatable enclosure having a fixed end and a movable end. The movable end is collapsible toward the fixed end to a contracted position when the enclosure is in a noninflated condition. Upon inflation, the movable end is movable away from the fixed end to an extended position. The movable end includes means for mounting an article such as a solar reflector thereon. The device also includes a plurality of position controlling means disposed about the movable end to effect adjusting movement of portions thereof by predetermined amounts and for controlling an angle at which the article disposed at the movable end is oriented. The plurality of position controlling means limits a suitable number degrees of freedom of the movable end for transmitting a steering motion thereto and for controlling the position thereof.

  5. Support and maneuvering device

    DOEpatents

    Wood, R.L.

    1987-03-23

    A support and maneuvering device includes an elongated flexible inflatable enclosure having a fixed end and a movable end. The movable end is collapsible toward the fixed end to a contracted position when the enclosure is in a noninflated condition. Upon inflation, the movable end is movable away from the fixed end to an extended position. The movable end includes means for mounting an article such as a solar reflector thereon. The device also includes a plurality of position controlling means disposed about the movable end to effect adjusting movement of portions thereof by predetermined amounts and for controlling an angle at which the article disposed at the movable end is oriented. The plurality of position controlling means limits a suitable number degrees of freedom of the movable end for transmitting a steering motion thereto and for controlling the position thereof. 9 figs.

  6. Aircraft agility maneuvers

    NASA Technical Reports Server (NTRS)

    Cliff, Eugene M.; Thompson, Brian G.

    1992-01-01

    A new dynamic model for aircraft motions is presented. This model can be viewed as intermediate between a point-mass model, in which the body attitude angles are control-like, and a rigid-body model, in which the body-attitude angles evolve according to Newton's Laws. Specifically, consideration is given to the case of symmetric flight, and a model is constructed in which the body roll-rate and the body pitch-rate are the controls. In terms of this body-rate model a minimum-time heading change maneuver is formulated. When the bounds on the body-rates are large the results are similar to the point-mass model in that the model can very quickly change the applied forces and produce an acceleration to turn the vehicle. With finite bounds on these rates, the forces change in a smooth way. This leads to a measurable effect of agility.

  7. Oxygenated drinking water enhances immune activity in pigs and increases immune responses of pigs during Salmonella typhimurium infection.

    PubMed

    Jung, Bock-Gie; Lee, Jin-A; Lee, Bong-Joo

    2012-12-01

    It has been considered that drinking oxygenated water improves oxygen availability, which may increase vitality and improve immune functions. The present study evaluated the effects of oxygenated drinking water on immune function in pigs. Continuous drinking of oxygenated water markedly increased peripheral blood mononuclear cell proliferation, interleukin-1β expression level and the CD4(+):CD8(+) cell ratio in pigs. During Salmonella Typhimurium infection, total leukocytes and relative cytokines expression levels were significantly increased in pigs consuming oxygenated water compared with pigs consuming tap water. These findings suggest that oxygenated drinking water enhances immune activity in pigs and increases immune responses of pigs during S. Typhimurium Infection.

  8. A geostationary longitude acquisition planning algorithm. [for maneuver planning of geosynchronous satellites

    NASA Technical Reports Server (NTRS)

    Petruzzo, C. J.; Bryant, W. C., Jr.; Nickerson, K. G.

    1977-01-01

    The paper is concerned with the phase of the geosynchronous mission termed station acquisition, which involves the maneuvering of a spacecraft to its geostationary longitude by means of the spacecraft propulsion system. An algorithm which assists in maneuver planning is described, and examples of its use are presented. The algorithm can be applied when sequences of more than three maneuvers are to be expected. While, in general, three maneuvers are sufficient to achieve the desired end conditions when orbital mechanics are the only consideration, operational considerations may add constraints resulting in an increased number of maneuvers required.

  9. Increased oxygen pulse after lung volume reduction surgery is associated with reduced dynamic hyperinflation.

    PubMed

    Lammi, Matthew R; Ciccolella, David; Marchetti, Nathaniel; Kohler, Malcolm; Criner, Gerard J

    2012-10-01

    Stroke volume augmentation during exercise is limited in chronic obstructive pulmonary disease patients because of decreased preload from dynamic hyperinflation (DH). We hypothesised that oxygen pulse and pulse pressure (PP) improve following lung volume reduction surgery (LVRS), and the magnitude of improvement correlates with reduction in DH. We compared 16 emphysema patients undergoing LVRS with six emphysema patients not undergoing LVRS. Oxygen pulse and PP were calculated from maximal cardiopulmonary exercise tests at baseline and 6 months. End-expiratory lung volume (EELV)/total lung capacity (TLC) represented DH. Comparisons were made between baseline and 6 months at metabolic isotimes (per cent maximal carbon dioxide production (V'(CO(2),max))). At baseline, the LVRS group was older with higher forced expiratory volume in 1 s, but had similar hyperinflation to the non-LVRS group. At 6 months, oxygen pulse (50%, 75%, and 100% V'(CO(2),max)) and PP (50% and 75% V'(CO(2),max)) increased in the LVRS, but not in the non-LVRS group. Baseline functional residual capacity/TLC inversely correlated with resting oxygen pulse (r= -0.449, p=0.04). Decreased EELV/TLC correlated with increased oxygen pulse at 75% (r= -0.487, p=0.02) and 100% V'(CO(2),max) (r= -0.548, p=0.008). LVRS led to increased oxygen pulse and PP during exercise at metabolic isotimes 6 months following surgery. Reductions in DH correlated with increases in oxygen pulse during exercise. Reducing lung volume may improve stroke volume response to exercise by decreasing DH.

  10. Maximal oxygen consumption increases with temperature in the European eel (Anguilla anguilla) through increased heart rate and arteriovenous extraction

    PubMed Central

    Claësson, Débora; Wang, Tobias; Malte, Hans

    2016-01-01

    Global warming results in increasing water temperature, which may represent a threat to aquatic ectotherms. The rising temperature affects ecology through physiology, by exerting a direct limiting effect on the individual. The mechanism controlling individual thermal tolerance is still elusive, but some evidence shows that the heart plays a central role, and that insufficient transport of oxygen to the respiring tissues may determine the thermal tolerance of animals. In this study, the influence of the heart in thermal limitation was investigated by measurements of aerobic scope in the European eel (Anguilla anguilla) together with measurements of cardiac output during rest and activity. Aerobic capacity was not limited by an acutely increased temperature in the European eel. Oxygen demand was met by an increase in heart rate and arteriovenous extraction. These findings suggest that thermal tolerance during exposure to acute temperature changes is not defined by oxygen transport capacity in the eel, and other mechanisms may play a central role in limiting thermal tolerance in these fish. PMID:27766150

  11. 14 CFR 25.1507 - Maneuvering speed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maneuvering speed. 25.1507 Section 25.1507....1507 Maneuvering speed. The maneuvering speed must be established so that it does not exceed the design maneuvering speed V A determined under § 25.335(c)....

  12. 14 CFR 25.1507 - Maneuvering speed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maneuvering speed. 25.1507 Section 25.1507....1507 Maneuvering speed. The maneuvering speed must be established so that it does not exceed the design maneuvering speed V A determined under § 25.335(c)....

  13. 14 CFR 25.1507 - Maneuvering speed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maneuvering speed. 25.1507 Section 25.1507....1507 Maneuvering speed. The maneuvering speed must be established so that it does not exceed the design maneuvering speed V A determined under § 25.335(c)....

  14. 14 CFR 25.1507 - Maneuvering speed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Maneuvering speed. 25.1507 Section 25.1507....1507 Maneuvering speed. The maneuvering speed must be established so that it does not exceed the design maneuvering speed V A determined under § 25.335(c)....

  15. 14 CFR 25.1507 - Maneuvering speed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Maneuvering speed. 25.1507 Section 25.1507....1507 Maneuvering speed. The maneuvering speed must be established so that it does not exceed the design maneuvering speed V A determined under § 25.335(c)....

  16. STS-134: Rendezvous Pitch Maneuver

    NASA Video Gallery

    On May 18, 2011, space shuttle Endeavour performed the Rendezvous Pitch Maneuver, or "backflip." With Commander Mark Kelly at the helm, Endeavour rotated 360 degrees backward to enable Internationa...

  17. STS-135: Rendezvous Pitch Maneuver

    NASA Video Gallery

    On July 10, 2011, space shuttle Atlantis performed the nine-minute Rendezvous Pitch Maneuver, or “backflip.” With Commander Chris Ferguson at the helm, Atlantis rotated 360 degrees backward to ...

  18. ARTEMIS Maneuvers into Lunar Orbit

    NASA Video Gallery

    This animation visualizes the maneuvers required to move the ARTEMIS spacecraft from their kidney-shaped paths on each side of the moon to orbiting the moon. It took one and a half years, over 90 o...

  19. STS-133: Rendezvous Pitch Maneuver

    NASA Video Gallery

    At 1:15 p.m. EST Saturday, space shuttle Discovery began the nine-minute Rendezvous Pitch Maneuver, or "backflip." With Commander Steve Lindsey at the helm, Discovery rotated 360 degrees backward t...

  20. Increased hemoglobin-oxygen affinity ameliorates bleomycin-induced hypoxemia and pulmonary fibrosis.

    PubMed

    Geng, Xin; Dufu, Kobina; Hutchaleelaha, Athiwat; Xu, Qing; Li, Zhe; Li, Chien-Ming; Patel, Mira P; Vlahakis, Nicholas; Lehrer-Graiwer, Josh; Oksenberg, Donna

    2016-09-01

    Although exertional dyspnea and worsening hypoxia are hallmark clinical features of idiopathic pulmonary fibrosis (IPF), no drug currently available could treat them. GBT1118 is a novel orally bioavailable small molecule that binds to hemoglobin and produces a concentration-dependent left shift of the oxygen-hemoglobin dissociation curve with subsequent increase in hemoglobin-oxygen affinity and arterial oxygen loading. To assess whether pharmacological modification of hemoglobin-oxygen affinity could ameliorate hypoxemia associated with lung fibrosis, we evaluated GBT1118 in a bleomycin-induced mouse model of hypoxemia and fibrosis. After pulmonary fibrosis and hypoxemia were induced, GBT1118 was administered for eight consecutive days. Hypoxemia was determined by monitoring arterial oxygen saturation, while the severity of pulmonary fibrosis was assessed by histopathological evaluation and determination of collagen and leukocyte levels in bronchoalveolar lavage fluid. We found that hemoglobin modification by GBT1118 had strong antihypoxemic therapeutic effects with improved arterial oxygen saturation to near normal level. Moreover, GBT1118 treatment significantly attenuated bleomycin-induced lung fibrosis, collagen accumulation, body weight loss, and leukocyte infiltration. This study is the first to suggest the beneficial effects of hemoglobin modification in fibrotic lungs and offers a promising and novel therapeutic strategy for the treatment of hypoxemia associated with chronic fibrotic lung disorders in human, including IPF. PMID:27624688

  1. Origin of the increase in resistivity of manganese-zinc ferrite polycrystals with oxygen partial pressure

    NASA Astrophysics Data System (ADS)

    Byeon, Soon Cheon; Hong, Kug Sun; Park, Jae Gwan; Kang, Won Nam

    1997-06-01

    In our present study, the origin of the increase in resistivity of polycrystalline Mn0.47Zn0.47Fe2.06O4 with increasing oxygen partial pressure was investigated by measuring thermoelectric power and electrical resistivity, and through analysis of grain size. The ferrous ion (Fe2+) concentration of the samples was estimated using the thermoelectric power data and it indicated that the increase of oxygen partial pressure accompanied only a 0.5 wt. % decrease in the concentration of Fe2+. The decrease in Fe2+ concentration failed to explain the order of magnitude increase in resistivity. Preferential oxidation of the grain boundaries did not contribute to the increase in resistivity since all the samples were cooled under the same conditions, i.e., constant oxidation potential. Impedance spectroscopy revealed that the increase in resistivity arose from the increase in resistivity of the grain boundary; this is discussed in terms of the microscopic shape factor, the brick-layer model, and the Maxwell-Wagner model. It is suggested that the increase in resistivity, with increasing oxygen partial pressure, originates from the increase in the microscopic shape factor of the grain boundary.

  2. Increased microsomal interaction with iron and oxygen radical generation after chronic acetone treatment.

    PubMed

    Puntarulo, S; Cederbaum, A I

    1988-01-12

    In vivo administration of acetone influences a variety of reactions catalyzed by rat liver microsomes. The effect of chronic treatment with acetone (1% acetone in the water for 10-12 days) on interaction with iron and subsequent oxygen radical generation by liver microsomes was evaluated. Microsomes from the acetone-treated rats displayed elevated rates of H2O2 generation, an increase in iron-dependent lipid peroxidation, and enhanced chemiluminescence upon the addition of t-butylhydroperoxide. The ferric EDTA-catalyzed production of formaldehyde from DMSO or of ethylene from 2-keto-4-thiomethylbutyrate was increased 2-fold after acetone treatment. This increase in hydroxyl radical generation was accompanied by a corresponding increase in NADPH utilization and was sensitive to inhibition by catalase and a competitive scavenger, ethanol, but not to superoxide dismutase. In vitro addition of acetone to microsomes had no effect on oxygen radical generation. Associated with the chronic acetone treatment was a 2-fold increase in the microsomal content of cytochrome P-450 and in the activity of NADPH-cytochrome-P-450 reductase. It appears that increased oxygen radical generation by microsomes after chronic acetone treatment reflects the increase in the major enzyme components which comprise the mixed-function oxidase system.

  3. Short-Term Molecular Acclimation Processes of Legume Nodules to Increased External Oxygen Concentration

    PubMed Central

    Avenhaus, Ulrike; Cabeza, Ricardo A.; Liese, Rebecca; Lingner, Annika; Dittert, Klaus; Salinas-Riester, Gabriela; Pommerenke, Claudia; Schulze, Joachim

    2016-01-01

    Nitrogenase is an oxygen labile enzyme. Microaerobic conditions within the infected zone of nodules are maintained primarily by an oxygen diffusion barrier (ODB) located in the nodule cortex. Flexibility of the ODB is important for the acclimation processes of nodules in response to changes in external oxygen concentration. The hypothesis of the present study was that there are additional molecular mechanisms involved. Nodule activity of Medicago truncatula plants were continuously monitored during a change from 21 to 25 or 30% oxygen around root nodules by measuring nodule H2 evolution. Within about 2 min of the increase in oxygen concentration, a steep decline in nitrogenase activity occurred. A quick recovery commenced about 8 min later. A qPCR-based analysis of the expression of genes for nitrogenase components showed a tendency toward upregulation during the recovery. The recovery resulted in a new constant activity after about 30 min, corresponding to approximately 90% of the pre-treatment level. An RNAseq-based comparative transcriptome profiling of nodules at that point in time revealed that genes for nodule-specific cysteine-rich (NCR) peptides, defensins, leghaemoglobin and chalcone and stilbene synthase were significantly upregulated when considered as a gene family. A gene for a nicotianamine synthase-like protein (Medtr1g084050) showed a strong increase in count number. The gene appears to be of importance for nodule functioning, as evidenced by its consistently high expression in nodules and a strong reaction to various environmental cues that influence nodule activity. A Tnt1-mutant that carries an insert in the coding sequence (cds) of that gene showed reduced nitrogen fixation and less efficient acclimation to an increased external oxygen concentration. It was concluded that sudden increases in oxygen concentration around nodules destroy nitrogenase, which is quickly counteracted by an increased neoformation of the enzyme. This reaction might be

  4. Short-Term Molecular Acclimation Processes of Legume Nodules to Increased External Oxygen Concentration.

    PubMed

    Avenhaus, Ulrike; Cabeza, Ricardo A; Liese, Rebecca; Lingner, Annika; Dittert, Klaus; Salinas-Riester, Gabriela; Pommerenke, Claudia; Schulze, Joachim

    2015-01-01

    Nitrogenase is an oxygen labile enzyme. Microaerobic conditions within the infected zone of nodules are maintained primarily by an oxygen diffusion barrier (ODB) located in the nodule cortex. Flexibility of the ODB is important for the acclimation processes of nodules in response to changes in external oxygen concentration. The hypothesis of the present study was that there are additional molecular mechanisms involved. Nodule activity of Medicago truncatula plants were continuously monitored during a change from 21 to 25 or 30% oxygen around root nodules by measuring nodule H2 evolution. Within about 2 min of the increase in oxygen concentration, a steep decline in nitrogenase activity occurred. A quick recovery commenced about 8 min later. A qPCR-based analysis of the expression of genes for nitrogenase components showed a tendency toward upregulation during the recovery. The recovery resulted in a new constant activity after about 30 min, corresponding to approximately 90% of the pre-treatment level. An RNAseq-based comparative transcriptome profiling of nodules at that point in time revealed that genes for nodule-specific cysteine-rich (NCR) peptides, defensins, leghaemoglobin and chalcone and stilbene synthase were significantly upregulated when considered as a gene family. A gene for a nicotianamine synthase-like protein (Medtr1g084050) showed a strong increase in count number. The gene appears to be of importance for nodule functioning, as evidenced by its consistently high expression in nodules and a strong reaction to various environmental cues that influence nodule activity. A Tnt1-mutant that carries an insert in the coding sequence (cds) of that gene showed reduced nitrogen fixation and less efficient acclimation to an increased external oxygen concentration. It was concluded that sudden increases in oxygen concentration around nodules destroy nitrogenase, which is quickly counteracted by an increased neoformation of the enzyme. This reaction might be

  5. Short-Term Molecular Acclimation Processes of Legume Nodules to Increased External Oxygen Concentration.

    PubMed

    Avenhaus, Ulrike; Cabeza, Ricardo A; Liese, Rebecca; Lingner, Annika; Dittert, Klaus; Salinas-Riester, Gabriela; Pommerenke, Claudia; Schulze, Joachim

    2015-01-01

    Nitrogenase is an oxygen labile enzyme. Microaerobic conditions within the infected zone of nodules are maintained primarily by an oxygen diffusion barrier (ODB) located in the nodule cortex. Flexibility of the ODB is important for the acclimation processes of nodules in response to changes in external oxygen concentration. The hypothesis of the present study was that there are additional molecular mechanisms involved. Nodule activity of Medicago truncatula plants were continuously monitored during a change from 21 to 25 or 30% oxygen around root nodules by measuring nodule H2 evolution. Within about 2 min of the increase in oxygen concentration, a steep decline in nitrogenase activity occurred. A quick recovery commenced about 8 min later. A qPCR-based analysis of the expression of genes for nitrogenase components showed a tendency toward upregulation during the recovery. The recovery resulted in a new constant activity after about 30 min, corresponding to approximately 90% of the pre-treatment level. An RNAseq-based comparative transcriptome profiling of nodules at that point in time revealed that genes for nodule-specific cysteine-rich (NCR) peptides, defensins, leghaemoglobin and chalcone and stilbene synthase were significantly upregulated when considered as a gene family. A gene for a nicotianamine synthase-like protein (Medtr1g084050) showed a strong increase in count number. The gene appears to be of importance for nodule functioning, as evidenced by its consistently high expression in nodules and a strong reaction to various environmental cues that influence nodule activity. A Tnt1-mutant that carries an insert in the coding sequence (cds) of that gene showed reduced nitrogen fixation and less efficient acclimation to an increased external oxygen concentration. It was concluded that sudden increases in oxygen concentration around nodules destroy nitrogenase, which is quickly counteracted by an increased neoformation of the enzyme. This reaction might be

  6. Improved Intratumoral Oxygenation Through Vascular Normalization Increases Glioma Sensitivity to Ionizing Radiation

    SciTech Connect

    McGee, Mackenzie C.; Hamner, J. Blair; Williams, Regan F.; Rosati, Shannon F.; Sims, Thomas L.; Ng, Catherine Y.; Gaber, M. Waleed; Calabrese, Christopher; Wu Jianrong; Nathwani, Amit C.; Merchant, Thomas E.; Davidoff, Andrew M.

    2010-04-15

    Purpose: Ionizing radiation, an important component of glioma therapy, is critically dependent on tumor oxygenation. However, gliomas are notable for areas of necrosis and hypoxia, which foster radioresistance. We hypothesized that pharmacologic manipulation of the typically dysfunctional tumor vasculature would improve intratumoral oxygenation and, thus, the antiglioma efficacy of ionizing radiation. Methods and Materials: Orthotopic U87 xenografts were treated with either continuous interferon-beta (IFN-beta) or bevacizumab, alone, or combined with cranial irradiation (RT). Tumor growth was assessed by quantitative bioluminescence imaging; the tumor vasculature using immunohistochemical staining, and tumor oxygenation using hypoxyprobe staining. Results: Both IFN-beta and bevaziumab profoundly affected the tumor vasculature, albeit with different cellular phenotypes. IFN-beta caused a doubling in the percentage of area of perivascular cell staining, and bevacizumab caused a rapid decrease in the percentage of area of endothelial cell staining. However, both agents increased intratumoral oxygenation, although with bevacizumab, the effect was transient, being lost by 5 days. Administration of IFN-beta or bevacizumab before RT was significantly more effective than any of the three modalities as monotherapy or when RT was administered concomitantly with IFN-beta or bevacizumab or 5 days after bevacizumab. Conclusion: Bevacizumab and continuous delivery of IFN-beta each induced significant changes in glioma vascular physiology, improving intratumoral oxygenation and enhancing the antitumor activity of ionizing radiation. Additional investigation into the use and timing of these and other agents that modify the vascular phenotype, combined with RT, is warranted to optimize cytotoxic activity.

  7. Automated maneuver planning using a fuzzy logic algorithm

    NASA Technical Reports Server (NTRS)

    Conway, D.; Sperling, R.; Folta, D.; Richon, K.; Defazio, R.

    1994-01-01

    Spacecraft orbital control requires intensive interaction between the analyst and the system used to model the spacecraft trajectory. For orbits with right mission constraints and a large number of maneuvers, this interaction is difficult or expensive to accomplish in a timely manner. Some automation of maneuver planning can reduce these difficulties for maneuver-intensive missions. One approach to this automation is to use fuzzy logic in the control mechanism. Such a prototype system currently under development is discussed. The Tropical Rainfall Measurement Mission (TRMM) is one of several missions that could benefit from automated maneuver planning. TRMM is scheduled for launch in August 1997. The spacecraft is to be maintained in a 350-km circular orbit throughout the 3-year lifetime of the mission, with very small variations in this orbit allowed. Since solar maximum will occur as early as 1999, the solar activity during the TRMM mission will be increasing. The increasing solar activity will result in orbital maneuvers being performed as often as every other day. The results of automated maneuver planning for the TRMM mission will be presented to demonstrate the prototype of the fuzzy logic tool.

  8. Software for Autonomous Spacecraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Bristow, John; Folta, Dave; Hawkins, Al; Dell, Greg

    2004-01-01

    The AutoCon computer programs facilitate and accelerate the planning and execution of orbital control maneuvers of spacecraft while analyzing and resolving mission constraints. AutoCon-F is executed aboard spacecraft, enabling the spacecraft to plan and execute maneuvers autonomously; AutoCon-G is designed for use on the ground. The AutoCon programs utilize advanced techniques of artificial intelligence, including those of fuzzy logic and natural-language scripting, to resolve multiple conflicting constraints and automatically plan maneuvers. These programs can be used to satisfy requirements for missions that involve orbits around the Earth, the Moon, or any planet, and are especially useful for missions in which there are requirements for frequent maneuvers and for resolution of complex conflicting constraints. During operations, the software targets new trajectories, places and sizes maneuvers, and controls spacecraft burns. AutoCon-G provides a userfriendly graphical interface, and can be used effectively by an analyst with minimal training. AutoCon-F reduces latency and supports multiple-spacecraft and formation-flying missions. The AutoCon architecture supports distributive processing, which can be critical for formation- control missions. AutoCon is completely object-oriented and can easily be enhanced by adding new objects and events. AutoCon-F was flight demonstrated onboard GSFC's EO-1 spacecraft flying in formation with Landsat-7.

  9. Dynamics of Voluntary Cough Maneuvers

    NASA Astrophysics Data System (ADS)

    Naire, Shailesh

    2008-11-01

    Voluntary cough maneuvers are characterized by transient peak expiratory flows (PEF) exceeding the maximum expiratory flow-volume (MEFV) curve. In some cases, these flows can be well in excess of the MEFV, generally referred to as supramaximal flows. Understanding the flow-structure interaction involved in these maneuvers is the main goal of this work. We present a simple theoretical model for investigating the dynamics of voluntary cough and forced expiratory maneuvers. The core modeling idea is based on a 1-D model of high Reynolds number flow through flexible-walled tubes. The model incorporates key ingredients involved in these maneuvers: the expiratory effort generated by the abdominal and expiratory muscles, the glottis and the flexibility and compliance of the lung airways. Variations in these allow investigation of the expiratory flows generated by a variety of single cough maneuvers. The model successfully reproduces PEF which is shown to depend on the cough generation protocol, the glottis reopening time and the compliance of the airways. The particular highlight is in simulating supramaximal PEF for very compliant tubes. The flow-structure interaction mechanisms behind these are discussed. The wave speed theory of flow limitation is used to characterize the PEF. Existing hypotheses of the origin of PEF, from cough and forced expiration experiments, are also tested using this model.

  10. Cardiac resynchronization therapy and AV optimization increase myocardial oxygen consumption, but increase cardiac function more than proportionally☆

    PubMed Central

    Kyriacou, Andreas; Pabari, Punam A.; Mayet, Jamil; Peters, Nicholas S.; Davies, D. Wyn; Lim, P. Boon; Lefroy, David; Hughes, Alun D.; Kanagaratnam, Prapa; Francis, Darrel P.; I.Whinnett, Zachary

    2014-01-01

    Background The mechanoenergetic effects of atrioventricular delay optimization during biventricular pacing (“cardiac resynchronization therapy”, CRT) are unknown. Methods Eleven patients with heart failure and left bundle branch block (LBBB) underwent invasive measurements of left ventricular (LV) developed pressure, aortic flow velocity-time-integral (VTI) and myocardial oxygen consumption (MVO2) at 4 pacing states: biventricular pacing (with VV 0 ms) at AVD 40 ms (AV-40), AVD 120 ms (AV-120, a common nominal AV delay), at their pre-identified individualised haemodynamic optimum (AV-Opt); and intrinsic conduction (LBBB). Results AV-120, relative to LBBB, increased LV developed pressure by a mean of 11(SEM 2)%, p = 0.001, and aortic VTI by 11(SEM 3)%, p = 0.002, but also increased MVO2 by 11(SEM 5)%, p = 0.04. AV-Opt further increased LV developed pressure by a mean of 2(SEM 1)%, p = 0.035 and aortic VTI by 4(SEM 1)%, p = 0.017. MVO2 trended further up by 7(SEM 5)%, p = 0.22. Mechanoenergetics at AV-40 were no different from LBBB. The 4 states lay on a straight line for Δexternal work (ΔLV developed pressure × Δaortic VTI) against ΔMVO2, with slope 1.80, significantly > 1 (p = 0.02). Conclusions Biventricular pacing and atrioventricular delay optimization increased external cardiac work done but also myocardial oxygen consumption. Nevertheless, the increase in cardiac work was ~ 80% greater than the increase in oxygen consumption, signifying an improvement in cardiac mechanoenergetics. Finally, the incremental effect of optimization on external work was approximately one-third beyond that of nominal AV pacing, along the same favourable efficiency trajectory, suggesting that AV delay dominates the biventricular pacing effect — which may therefore not be mainly “resynchronization”. PMID:24332598

  11. Is there central fatigue during simulated air combat maneuvering?

    PubMed

    Bain, B; Jacobs, I; Buick, F

    1995-01-01

    This study tested the hypothesis that repeated exposure to high levels of +Gz acceleration, in conjunction with repeated execution of an Anti-G Straining Maneuver (AGSM), causes central fatigue, presumably by impairing central nervous system (CNS) function. We speculated that central fatigue would impair the ability to recruit sufficient musculature at the intensity required to perform an adequate anti-G straining maneuver. Central fatigue was evaluated by measuring maximal force generation and surface electromyographic activity of leg extensor muscles before, during, and immediately upon termination of an SACM, and comparing these values to those obtained when the muscles were electrically stimulated during maximal voluntary contractions (MVCs). We assumed that any observed increase in force generation during the MVCs, caused by the stimulation, would indicate central fatigue. G-tolerance time was 230 +/- 172 s. Hypoxia was induced by the SACM as the arterial oxygen saturation decreased significantly from 97% to 90%. In spite of this hypoxia, there was no significant change in MVC force when the pre- and post-SACM values were compared. Electrical stimulation during the MVC's did not cause an increase in force generation. The average forces generated during the +7 Gz phase of the SACM were only about 35% of MVC force. This force value did not change significantly during the SACM. The results indicate that the inability to continue to perform the AGSM during an SACM is not likely due to central fatigue or to fatigue of the large skeletal muscle groups we have examined.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Diamagnetic levitation enhances growth of liquid bacterial cultures by increasing oxygen availability.

    PubMed

    Dijkstra, Camelia E; Larkin, Oliver J; Anthony, Paul; Davey, Michael R; Eaves, Laurence; Rees, Catherine E D; Hill, Richard J A

    2011-03-01

    Diamagnetic levitation is a technique that uses a strong, spatially varying magnetic field to reproduce aspects of weightlessness, on the Earth. We used a superconducting magnet to levitate growing bacterial cultures for up to 18 h, to determine the effect of diamagnetic levitation on all phases of the bacterial growth cycle. We find that diamagnetic levitation increases the rate of population growth in a liquid culture and reduces the sedimentation rate of the cells. Further experiments and microarray gene analysis show that the increase in growth rate is owing to enhanced oxygen availability. We also demonstrate that the magnetic field that levitates the cells also induces convective stirring in the liquid. We present a simple theoretical model, showing how the paramagnetic force on dissolved oxygen can cause convection during the aerobic phases of bacterial growth. We propose that this convection enhances oxygen availability by transporting oxygen around the liquid culture. Since this process results from the strong magnetic field, it is not present in other weightless environments, e.g. in Earth orbit. Hence, these results are of significance and timely to researchers considering the use of diamagnetic levitation to explore effects of weightlessness on living organisms and on physical phenomena. PMID:20667843

  13. Diamagnetic levitation enhances growth of liquid bacterial cultures by increasing oxygen availability

    PubMed Central

    Dijkstra, Camelia E.; Larkin, Oliver J.; Anthony, Paul; Davey, Michael R.; Eaves, Laurence; Rees, Catherine E. D.; Hill, Richard J. A.

    2011-01-01

    Diamagnetic levitation is a technique that uses a strong, spatially varying magnetic field to reproduce aspects of weightlessness, on the Earth. We used a superconducting magnet to levitate growing bacterial cultures for up to 18 h, to determine the effect of diamagnetic levitation on all phases of the bacterial growth cycle. We find that diamagnetic levitation increases the rate of population growth in a liquid culture and reduces the sedimentation rate of the cells. Further experiments and microarray gene analysis show that the increase in growth rate is owing to enhanced oxygen availability. We also demonstrate that the magnetic field that levitates the cells also induces convective stirring in the liquid. We present a simple theoretical model, showing how the paramagnetic force on dissolved oxygen can cause convection during the aerobic phases of bacterial growth. We propose that this convection enhances oxygen availability by transporting oxygen around the liquid culture. Since this process results from the strong magnetic field, it is not present in other weightless environments, e.g. in Earth orbit. Hence, these results are of significance and timely to researchers considering the use of diamagnetic levitation to explore effects of weightlessness on living organisms and on physical phenomena. PMID:20667843

  14. Identification of aerodynamic models for maneuvering aircraft

    NASA Technical Reports Server (NTRS)

    Chin, Suei; Lan, C. Edward

    1990-01-01

    Due to the requirement of increased performance and maneuverability, the flight envelope of a modern fighter is frequently extended to the high angle-of-attack regime. Vehicles maneuvering in this regime are subjected to nonlinear aerodynamic loads. The nonlinearities are due mainly to three-dimensional separated flow and concentrated vortex flow that occur at large angles of attack. Accurate prediction of these nonlinear airloads is of great importance in the analysis of a vehicle's flight motion and in the design of its flight control system. A satisfactory evaluation of the performance envelope of the aircraft may require a large number of coupled computations, one for each change in initial conditions. To avoid the disadvantage of solving the coupled flow-field equations and aircraft's motion equations, an alternate approach is to use a mathematical modeling to describe the steady and unsteady aerodynamics for the aircraft equations of motion. Aerodynamic forces and moments acting on a rapidly maneuvering aircraft are, in general, nonlinear functions of motion variables, their time rate of change, and the history of maneuvering. A numerical method was developed to analyze the nonlinear and time-dependent aerodynamic response to establish the generalized indicial function in terms of motion variables and their time rates of change.

  15. The role of oxygen-increased respirator in humans ascending to high altitude

    PubMed Central

    2012-01-01

    Background Acute mountain sickness (AMS) is common for people who live in low altitude areas ascending to the high altitude. Many instruments have been developed to treat mild cases of AMS. However, long-lasting and portable anti-hypoxia equipment for individual is not yet available. Methods Oxygen-increased respirator (OIR) has been designed to reduce the risk of acute mountain sickness in acute exposure to low air pressure. It can increase the density of oxygen by increasing total atmospheric pressure in a mask. Male subjects were screened, and eighty-eight were qualified to perform the experiments. The subjects were divided into 5 groups and were involved in some of the tests at 4 different altitudes (Group 1, 2: 3700 m; Group 3,4,5: 4000 m, 4700 m, 5380 m) with and without OIR. These tests include heart rate, saturation of peripheral oxygen (SpO2), malondialdehyde (MDA), superoxide dismutase (SOD), blood lactate (BLA) and PWC (physical work capacity) -170. Results The results showed that higher SpO2, lower heart rate (except during exercise) and better recovery of heart rate were observed from all the subjects ’with OIR’ compared with ’without OIR’ (P<0.05). Moreover, compared with ’without OIR’, subjects ’with OIR’ in Group 1 had lower concentrations of MDA and BLA, and a higher concentration of SOD (P<0.05), while subjects ’with OIR’ in Group 2 showed better physical capacity (measured by the PWC-170) (P<0.05). The additional experiment conducted in a hypobaric chamber (simulating 4,000 m) showed that the partial pressure of oxygen in blood and arterial oxygen saturation were higher ’with OIR’ than ’without OIR’ (P<0.05). Conclusions We suggested that OIR may play a useful role in protecting people ascending to high altitude before acclimatization. PMID:22898206

  16. Effect of increased oxygen tension on flicker-induced vasodilatation in the human retina.

    PubMed

    Palkovits, Stefan; Told, Reinhard; Boltz, Agnes; Schmidl, Doreen; Popa Cherecheanu, Alina; Schmetterer, Leopold; Garhöfer, Gerhard

    2014-12-01

    In the retina, blood flow and neural activity are tightly coupled. Stimulation of the retina with flickering light is accompanied by an increase in blood flow. The current study seeks to investigate whether an increase in oxygen tension modulates flicker (FL)-induced vasodilatation in the human retina. A total of 52 healthy volunteers were included. Via a breathing mask, 100% oxygen (O(2)) was administered in one, a mixture of 8% carbon dioxide and 92% oxygen (C/O) in a second cohort. Retinal vessel diameters were measured with a Vessel Analyzer and FL responses were assessed before and during the breathing periods. At baseline, FL stimulation increased retinal vessel diameters by +3.7±2.3% in arteries and by +5.1±3.7% in veins. Breathing of C/O led to a decrease in arterial (-9.0±6.9%) and venous (-11.3±5.9%) vessel calibers. Flicker response was increased to 5.7±2.5% in arteries and to 8.6±4.1% in veins. Breathing of pure O2 induced a vasoconstriction of vessel diameters by -14.0±5.3% in arteries and -18.4±7.0% in veins and increased FL responses in arteries (+6.2±2.8%) and veins (+7.2±3.1%). Systemic hyperoxia increases FL-induced retinal vasodilatation in the retina. The mechanism by which oxygen modulates the hyperemic response to FL stimulation remains to be elucidated.

  17. Effect of increased oxygen tension on flicker-induced vasodilatation in the human retina

    PubMed Central

    Palkovits, Stefan; Told, Reinhard; Boltz, Agnes; Schmidl, Doreen; Popa Cherecheanu, Alina; Schmetterer, Leopold; Garhöfer, Gerhard

    2014-01-01

    In the retina, blood flow and neural activity are tightly coupled. Stimulation of the retina with flickering light is accompanied by an increase in blood flow. The current study seeks to investigate whether an increase in oxygen tension modulates flicker (FL)-induced vasodilatation in the human retina. A total of 52 healthy volunteers were included. Via a breathing mask, 100% oxygen (O2) was administered in one, a mixture of 8% carbon dioxide and 92% oxygen (C/O) in a second cohort. Retinal vessel diameters were measured with a Vessel Analyzer and FL responses were assessed before and during the breathing periods. At baseline, FL stimulation increased retinal vessel diameters by +3.7±2.3% in arteries and by +5.1±3.7% in veins. Breathing of C/O led to a decrease in arterial (−9.0±6.9%) and venous (−11.3±5.9%) vessel calibers. Flicker response was increased to 5.7±2.5% in arteries and to 8.6±4.1% in veins. Breathing of pure O2 induced a vasoconstriction of vessel diameters by −14.0±5.3% in arteries and −18.4±7.0% in veins and increased FL responses in arteries (+6.2±2.8%) and veins (+7.2±3.1%). Systemic hyperoxia increases FL-induced retinal vasodilatation in the retina. The mechanism by which oxygen modulates the hyperemic response to FL stimulation remains to be elucidated. PMID:25248833

  18. Oxygenated drinking water enhances immune activity in broiler chicks and increases survivability against Salmonella Gallinarum in experimentally infected broiler chicks.

    PubMed

    Jung, Bock-Gie; Lee, Jin-A; Nam, Kyoung-Woo; Lee, Bong-Joo

    2012-03-01

    It has been suggested that drinking oxygenated water may improve oxygen availability, which may increase vitality and improving immune activity. The present study evaluated the immune enhancing effects of oxygenated drinking water in broiler chicks and demonstrated the protective efficacy of oxygenated drinking water against Salmonella Gallinarum in experimentally infected broiler chicks. Continuous drinking of oxygenated water markedly increased serum lysozyme activity, peripheral blood mononuclear cell proliferation and the CD4(+)/CD8(+) splenocyte ratio in broiler chicks. In the chicks experimentally infected with S. Gallinarum, oxygenated drinking water alleviated symptoms and increased survival. These findings suggest that oxygenated drinking water enhances immune activity in broiler chicks, and increases survivability against S. Gallinarum in experimentally infected broiler chicks.

  19. High Oxygen Partial Pressure Decreases Anemia-Induced Heart Rate Increase Equivalent to Transfusion

    PubMed Central

    Feiner, John R.; Finlay-Morreale, Heather E.; Toy, Pearl; Lieberman, Jeremy A.; Viele, Maurene K.; Hopf, Harriet W.; Weiskopf, Richard B.

    2011-01-01

    Background Anemia is associated with morbidity and mortality and frequently leads to transfusion of erythrocytes. We sought to compare directly the effect of high inspired oxygen fraction vs. transfusion of erythrocytes on the anemia-induced increased heart rate (HR) in humans undergoing experimental acute isovolemic anemia. Methods We combined HR data from healthy subjects undergoing experimental isovolemic anemia in seven studies performed by our group. We examined HR changes associated with breathing 100% oxygen by non-rebreathing face mask vs. transfusion of erythrocytes at their nadir hemoglobin (Hb) concentration of 5 g/dL. Data were analyzed using a mixed-effects model. Results HR had an inverse linear relationship to hemoglobin concentration with a mean increase of 3.9 beats per minute per gram of Hb (beats/min/g Hb) decrease (95% confidence interval [CI], 3.7 – 4.1 beats/min/g Hb), P < 0.0001. Return of autologous erythrocytes significantly decreased HR by 5.3 beats/min/g Hb (95% CI, 3.8 – 6.8 beats/min/g Hb) increase, P < 0.0001. HR at nadir Hb of 5.6 g/dL (95% CI, 5.5 – 5.7 g/dL) when breathing air (91.4 beats/min; 95% CI, 87.6 – 95.2 beats/min) was reduced by breathing 100% oxygen (83.0 beats/min; 95% CI, 79.0 -87.0 beats/min), P < 0.0001. The HR at hemoglobin 5.6 g/dL when breathing oxygen was equivalent to the HR at Hb 8.9 g/dL when breathing air. Conclusions High arterial oxygen partial pressure reverses the heart rate response to anemia, probably owing to its usability, rather than its effect on total oxygen content. The benefit of high arterial oxygen partial pressure has significant potential clinical implications for the acute treatment of anemia and results of transfusion trials. PMID:21768873

  20. Operational Experiences in Planning and Reconstructing Aqua Inclination Maneuvers

    NASA Technical Reports Server (NTRS)

    Rand, David; Reilly, Jacqueline; Schiff, Conrad

    2004-01-01

    As the lead satellite in NASA's growing Earth Observing System (EOS) PM constellation, it is increasingly critical that Aqua maintain its various orbit requirements. The two of interest for this paper are maintaining an orbit inclination that provides for a consistent mean local time and a semi-major Axis (SMA) that allows for ground track repeatability. Maneuvers to adjust the orbit inclination involve several flight dynamics constraints and complexities which make planning such maneuvers challenging. In particular, coupling between the orbital and attitude degrees of freedom lead to changes in SMA when changes in inclination are effected. A long term mission mean local time trend analysis was performed in order to determine the size and placement of the required inclination maneuvers. Following this analysis, detailed modeling of each burn and its Various segments was performed to determine its effects on the immediate orbit state. Data gathered from an inclination slew test of the spacecraft and first inclination maneuver uncovered discrepancies in the modeling method that were investigated and resolved. The new modeling techniques were applied and validated during the second spacecraft inclination maneuver. These improvements should position Aqua to successfully complete a series of inclination maneuvers in the fall of 2004. The following paper presents the events and results related

  1. Increased Oxygen Recovery from Sabatier Systems Using Plasma Pyrolysis Technology and Metal Hydride Separation

    NASA Technical Reports Server (NTRS)

    Greenwood, Zachary W.; Abney, Morgan B.; Perry, Jay L.; Miller, Lee A.; Dahl, Roger W.; Hadley, Neal M.; Wambolt, Spencer R.; Wheeler, Richard R.

    2015-01-01

    State-of-the-art life support carbon dioxide (CO2) reduction technology is based on the Sabatier reaction where less than 50% of the oxygen required for the crew is recovered from metabolic CO2. The reaction produces water as the primary product and methane as a byproduct. Oxygen recovery is constrained by the limited availability of reactant hydrogen. This is further exacerbated when Sabatier methane (CH4) is vented as a waste product resulting in a continuous loss of reactant hydrogen. Post-processing methane with the Plasma Pyrolysis Assembly (PPA) to recover hydrogen has the potential to dramatically increase oxygen recovery and thus drastically reduce the logistical challenges associated with oxygen resupply. The PPA decomposes methane into predominantly hydrogen and acetylene. Due to the highly unstable nature of acetylene, a separation system is necessary to purify hydrogen before it is recycled back to the Sabatier reactor. Testing and evaluation of a full-scale Third Generation PPA is reported and investigations into metal hydride hydrogen separation technology is discussed.

  2. Reactive oxygen species production is increased in the peripheral blood monocytes of obese patients.

    PubMed

    Degasperi, Giovanna R; Denis, Raphael G P; Morari, Joseane; Solon, Carina; Geloneze, Bruno; Stabe, Christiane; Pareja, José Carlos; Vercesi, Aníbal E; Velloso, Lício A

    2009-08-01

    Infiltrating macrophages play an important role in the production of inflammatory mediators by the adipose tissue of obese subjects. To reach the adipose tissue, peripheral monocytes are recruited by locally produced chemoattractants. However, little is known about the activation of monocytes in the peripheral blood of obese subjects. The objective of this study was to determine reactive oxygen species and endoplasmic reticulum stress as early markers of monocytic commitment with an inflammatory phenotype in the peripheral blood of nondiabetic obese patients. Patients were recruited from an academic general hospital; controls were voluntary students. Seven lean controls and 6 nondiabetic obese patients were included in the study. Monocytes were prepared from peripheral blood. Immunoblot, flow cytometry, and polymerase chain reaction were used to determine reactive oxygen species and endoplasmic reticulum stress. Increased reactive oxygen species and activation of endoplasmic reticulum stress were detected in the monocytes from obese patients. Reducing endoplasmic reticulum stress with a chemical chaperone reversed monocytic activation, as determined by the reduction of reactive oxygen species production. Thus, monocytes from nondiabetic obese patients are already committed with an inflammatory phenotype in peripheral blood; and reducing endoplasmic reticulum stress negatively modulates their activation.

  3. Supplemental oxygen attenuates the increase in wound bacterial growth during simulated aeromedical evacuation in goats

    PubMed Central

    Earnest, Ryan E.; Sonnier, Dennis I.; Makley, Amy T.; Campion, Eric M.; Wenke, Joseph C.; Bailey, Stephanie R.; Dorlac, Warren C.; Lentsch, Alex B.; Pritts, Timothy A.

    2012-01-01

    Background Bacterial growth in soft tissue and open fractures is a known risk factor for tissue loss and complications in contaminated musculoskeletal wounds. Current care for battlefield casualties with soft tissue and musculoskeletal wounds includes tactical and strategic aeromedical evacuation (AE). This exposes patients to a hypobaric, hypoxic environment. In the present study, we sought to determine whether exposure to AE alters bacterial growth in contaminated complex musculoskeletal wounds and whether supplemental oxygen had any effect on wound infections during simulated AE. Methods A caprine model of a contaminated complex musculoskeletal wound was employed. Complex musculoskeletal wounds were created and inoculated with bioluminescent Pseudomonas aeruginosa. Goats were divided into three experimental groups: ground control, simulated aeromedical evacuation (AE), and simulated AE with supplemental oxygen (AE+O2). Simulated AE was induced in a hypobaric chamber pressurized to 8800 feet for 7 hours. Bacterial luminescence was measured using a photon counting camera at three timepoints: preflight (20 hours post surgery), postflight (7 hours from preflight and 27 hours post-surgery), and necropsy (24 hours from preflight and 44 hours post surgery). Results There was a significant increase in bacterial growth in the AE group compared to the ground control group measured postflight and at necropsy. Simulated AE induced hypoxia with oxygen saturation less than 93%. Supplemental oxygen corrected the hypoxia and significantly reduced bacterial growth in wounds at necropsy. Conclusions Hypoxia induced during simulated AE enhances bacterial growth in complex musculoskeletal wounds which can be prevented with the application of supplemental oxygen to the host. PMID:22743376

  4. Use of Atomic Oxygen for Increased Water Contact Angles of Various Polymers for Biomedical Applications

    NASA Technical Reports Server (NTRS)

    deGroh, Kim; Berger, Lauren; Roberts, Lily

    2009-01-01

    The purpose of this study was to determine the effect of atomic oxygen (AO) exposure on the hydrophilicity of nine different polymers for biomedical applications. Atomic oxygen treatment can alter the chemistry and morphology of polymer surfaces, which may increase the adhesion and spreading of cells on Petri dishes and enhance implant growth. Therefore, nine different polymers were exposed to atomic oxygen and water-contact angle, or hydrophilicity, was measured after exposure. To determine whether hydrophilicity remains static after initial atomic oxygen exposure, or changes with higher fluence exposures, the contact angles between the polymer and water droplet placed on the polymer s surface were measured versus AO fluence. The polymers were exposed to atomic oxygen in a 100-W, 13.56-MHz radio frequency (RF) plasma asher, and the treatment was found to significantly alter the hydrophilicity of non-fluorinated polymers. Pristine samples were compared with samples that had been exposed to AO at various fluence levels. Minimum and maximum fluences for the ashing trials were set based on the effective AO erosion of a Kapton witness coupon in the asher. The time intervals for ashing were determined by finding the logarithmic values of the minimum and maximum fluences. The difference of these two values was divided by the desired number of intervals (ideally 10). The initial desired fluence was then multiplied by this result (2.37), as was each subsequent desired fluence. The flux in the asher was determined to be approximately 3.0 x 10(exp 15) atoms/sq cm/sec, and each polymer was exposed to a maximum fluence of 5.16 x 10(exp 20) atoms/sq cm.

  5. Maneuvering technology for advanced fighter aircraft

    NASA Technical Reports Server (NTRS)

    Alexander, Michael G.; Harris, Scott H.; Byers, Richard H.

    1992-01-01

    The need for increased maneuverability has its genesis from the first aerial combat engagement when two adversaries entangled themselves in a deadly aerial dance trying to gain the advantage over the other. It has only been in the past two decades that technologies have been investigated to increase aircraft control at maneuver attitudes that are typically dominated by highly separated flows. These separated flow regions are aggravated by advanced fighter aircraft shapes required to defeat an electronic enemy. This paper discusses passive and active devices that can be used to enhance the maneuverability of advanced fighter aircraft through vortex flow control, boundary layer control, and innovative flow manipulation.

  6. Increased Efficiency in SI Engine with Air Replaced by Oxygen in Argon Mixture

    SciTech Connect

    Killingsworth, N J; Rapp, V H; Flowers, D L; Aceves, S M; Chen, J; Dibble, R

    2010-01-13

    Basic engine thermodynamics predicts that spark ignited engine efficiency is a function of both the compression ratio of the engine and the specific heat ratio of the working fluid. In practice the compression ratio of the engine is often limited due to knock. Both higher specific heat ratio and higher compression ratio lead to higher end gas temperatures and increase the likelihood of knock. In actual engine cycles, heat transfer losses increase at higher compression ratios and limit efficiency even when the knock limit is not reached. In this paper we investigate the role of both the compression ratio and the specific heat ratio on engine efficiency by conducting experiments comparing operation of a single-cylinder variable-compression-ratio engine with both hydrogen-air and hydrogen-oxygen-argon mixtures. For low load operation it is found that the hydrogen-oxygen-argon mixtures result in higher indicated thermal efficiencies. Peak efficiency for the hydrogen-oxygen-argon mixtures is found at compression ratio 5.5 whereas for the hydrogen-air mixture with an equivalence ratio of 0.24 the peak efficiency is found at compression ratio 13. We apply a three-zone model to help explain the effects of specific heat ratio and compression ratio on efficiency. Operation with hydrogen-oxygen-argon mixtures at low loads is more efficient because the lower compression ratio results in a substantially larger portion of the gas to reside in the adiabatic core rather than in the boundary layer and in the crevices, leading to less heat transfer and more complete combustion.

  7. 33 CFR 84.23 - Maneuvering light.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be...

  8. 33 CFR 84.23 - Maneuvering light.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be...

  9. 33 CFR 84.23 - Maneuvering light.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be...

  10. 33 CFR 84.23 - Maneuvering light.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be...

  11. 33 CFR 84.23 - Maneuvering light.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be...

  12. Using the Two-Burn Escape Maneuver for Fast Transfers in the Solar System and Beyond

    NASA Technical Reports Server (NTRS)

    Adams, Robert B.; Richardson, Georgia A.

    2010-01-01

    The two-burn maneuver to escape the gravitational pull of a central body is described. The maneuver, originally suggested by Hermann Oberth, improves efficiency considerably for a wide range of missions of interest in space exploration and scientific investigation. A clear delineation of when the maneuver is more effective is given, as are methods to extract the most advantage when using the maneuver. Some examples are given of how this maneuver can enable exploration of the outer solar system, near interstellar space, and crewed missions to Mars and beyond. The maneuver has the potential to halve the required infrastructure associated with a crewed mission to Mars and achieve increased solar escape velocities with existing spacecraft technologies.

  13. Localized increase of tissue oxygen tension by magnetic targeted drug delivery

    NASA Astrophysics Data System (ADS)

    Liong, Celine; Ortiz, Daniel; Ao-ieong, Eilleen; Navati, Mahantesh S.; Friedman, Joel M.; Cabrales, Pedro

    2014-07-01

    Hypoxia is the major hindrance to successful radiation therapy of tumors. Attempts to increase the oxygen (O2) tension (PO2) of tissue by delivering more O2 have been clinically disappointing, largely due to the way O2 is transported and released by the hemoglobin (Hb) within the red blood cells (RBCs). Systemic manipulation of O2 transport increases vascular resistance due to metabolic autoregulation of blood flow to prevent over oxygenation. This study investigates a new technology to increase O2 delivery to a target tissue by decreasing the Hb-O2 affinity of the blood circulating within the targeted tissue. As the Hb-O2 affinity decreases, the tissue PO2 to satisfy tissue O2 metabolic needs increases without increasing O2 delivery or extraction. Paramagnetic nanoparticles (PMNPs), synthetized using gadolinium oxide, were coated with the cell permeable Hb allosteric effector L35 (3,5-trichlorophenylureido-phenoxy-methylpropionic acid). L35 decreases Hb affinity for O2 and favors the release of O2. The L35-coated PMNPs (L35-PMNPs) were intravenously infused (10 mg kg-1) to hamsters instrumented with the dorsal window chamber model. A magnetic field of 3 mT was applied to localize the effects of the L35-PMNPs to the window chamber. Systemic O2 transport characteristics and microvascular tissue oxygenation were measured after administration of L35-PMNPs with and without magnetic field. The tissue PO2 in untreated control animals was 25.2 mmHg. L35-PMNPs without magnetic field decreased tissue PO2 to 23.4 mmHg, increased blood pressure, and reduced blood flow, largely due to systemic modification of Hb-O2 affinity. L35-PMNPs with magnetic field increased tissue PO2 to 27.9 mmHg, without systemic or microhemodynamic changes. These results indicate that localized modification of Hb-O2 affinity can increase PO2 of target tissue without affecting systemic O2 delivery or triggering O2 autoregulation mechanisms. This technology can be used to treat local hypoxia and to

  14. Zinc Induces Apoptosis of Human Melanoma Cells, Increasing Reactive Oxygen Species, p53 and FAS Ligand.

    PubMed

    Provinciali, Mauro; Pierpaoli, Elisa; Bartozzi, Beatrice; Bernardini, Giovanni

    2015-10-01

    The aim of this study was to examine the in vitro effect of zinc on the apoptosis of human melanoma cells, by studying the zinc-dependent modulation of intracellular levels of reactive oxygen species (ROS) and of p53 and FAS ligand proteins. We showed that zinc concentrations ranging from 33.7 μM to 75 μM Zn(2+) induced apoptosis in the human melanoma cell line WM 266-4. This apoptosis was associated with an increased production of intracellular ROS, and of p53 and FAS ligand protein. Treatment of tumor cells with the antioxidant N-acetylcysteine was able to prevent Zn(2+)-induced apoptosis, as well as the increase of p53 and FAS ligand protein induced by zinc. Zinc induces apoptosis in melanoma cells by increasing ROS and this effect may be mediated by the ROS-dependent induction of p53 and FAS/FAS ligand.

  15. Increased strength and decreased flexibility are related to reduced oxygen cost of walking

    PubMed Central

    McCarthy, John P.; Bryan, David R.; Zuckerman, Paul A.; Bamman, Marcas M.; Byrne, Nuala M.

    2009-01-01

    Purpose was determine effects resistance training/weight loss induced changes in muscular strength and flexibility have on net walking oxygen uptake (netVO2). Sixty-seven premenopausal women lost 12 kg. Before weight loss subjects were assigned to diet (WL) or diet/3 days per week resistance training (WLRT). Resting energy expenditure, oxygen uptake while walking at 4.84 km h−1 on the flat and up 2.5% grade, isometric knee extension strength, and flexibility of the knee extensors and plantar flexors were measured. Strength increased in WLRT (+36 N) but not in WL (−24 N). NetVO2 decreased significantly while flat walking (7.3%) and 2.5% grade walking (5.7%) in WLRT, but not in WL. Delta strength was negatively while delta knee extensor and plantar flexor flexibility were positively related to delta netVO2. Decreases in walking and grade netVO2 were independently and positively related to increased knee extension strength and decreased knee extensor and plantar flexor flexibility. PMID:18758805

  16. Manned maneuvering unit latching mechanism

    NASA Technical Reports Server (NTRS)

    Allton, C. S.

    1980-01-01

    The astronaut/Manned Maneuvering Unit interface, which presented a challenging set of requirements for a latching mechanism, is described. A spring loaded cam segment with variable ratio pulley release actuator was developed to meet the requirements. To preclude jamming of the mechanism, special precautions were taken such as spring loaded bearing points and careful selection of materials to resist cold welding. The mechanism successfully passed a number of tests which partially simulated orbital conditions.

  17. Maneuver Optimization through Simulated Annealing

    NASA Astrophysics Data System (ADS)

    de Vries, W.

    2011-09-01

    We developed an efficient method for satellite maneuver optimization. It is based on a Monte Carlo (MC) approach in combination with Simulated Annealing. The former component enables us to consider all imaginable trajectories possible given the current satellite position and its available thrust, while the latter approach ensures that we reliably find the best global optimization solution. Furthermore, this optimization setup is eminently scalable. It runs efficiently on the current multi-core generation of desktop computers, but is equally at home on massively parallel high performance computers (HPC). The baseline method for desktops uses a modified two-body propagator that includes the lunar gravitational force, and corrects for nodal and apsidal precession. For the HPC environment, on the other hand, we can include all the necessary components for a full force-model propagation: higher gravitational moments, atmospheric drag, solar radiation pressure, etc. A typical optimization scenario involves an initial orbit and a destination orbit / trajectory, a time period under consideration, and an available amount of thrust. After selecting a particular optimization (e.g., least amount of fuel, shortest maneuver), the program will determine when and in what direction to burn by what amount. Since we are considering all possible trajectories, we are not constrained to any particular transfer method (e.g., Hohmann transfers). Indeed, in some cases gravitational slingshots around the Earth turn out to be the best result. The paper will describe our approach in detail, its complement of optimizations for single- and multi-burn sequences, and some in-depth examples. In particular, we highlight an example where it is used to analyze a sequence of maneuvers after the fact, as well as showcase its utility as a planning and analysis tool for future maneuvers.

  18. Using Mean Orbit Period in Mars Reconnaissance Orbiter Maneuver Design

    NASA Technical Reports Server (NTRS)

    Chung, Min-Kun J.; Menon, Premkumar R.; Wagner, Sean V.; Williams, Jessica L.

    2014-01-01

    Mars Reconnaissance Orbiter (MRO) has provided communication relays for a number of Mars spacecraft. In 2016 MRO is expected to support a relay for NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) spacecraft. In addition, support may be needed by another mission, ESA's ExoMars EDL Demonstrator Module's (EDM), only 21 days after the InSight coverage. The close proximity of these two events presents a unique challenge to a conventional orbit synchronization maneuver where one deterministic maneuver is executed prior to each relay. Since the two events are close together and the difference in required phasing between InSight and EDM may be up to half an orbit (yielding a large execution error), the downtrack timing error can increase rapidly at the EDM encounter. Thus, a new maneuver strategy that does not require a deterministic maneuver in-between the two events (with only a small statistical cleanup) is proposed in the paper. This proposed strategy rests heavily on the stability of the mean orbital period. The ability to search and set the specified mean period is fundamental in the proposed maneuver design as well as in understanding the scope of the problem. The proposed strategy is explained and its result is used to understand and solve the problem in the flight operations environment.

  19. Early Increase of Reactive Oxygen Species in Pea Seedling Roots Under Hypergravity

    NASA Astrophysics Data System (ADS)

    Jadko, Sergiy; Syvash, Alexander; Klymchuk, Dmytro

    Early increase of intensity of peroxidation and formation of reactive oxygen species (ROS) in plant cells take place under various impacts. The ROS can act as second messengers in mechanism of cell responses (Mittler et al 2006; Jadko et al 2007). Early stages of ROS content (chemiluminescence, ChL) in pea root cells under 3, 5, 10 and 15g during centrifugation have been investigated. After 30 min of centrifugation, especially under 10 and 15g, the intensity of ChL increased and was higher on 40-50% comparing to controls. Than the ChL slowly decreased and reached the controls in 1 hour. The changes of the ChL depend on both the dose and the duration of centrifugation. The role of ROS in mechanism of cell response to hypergravity is discussed.

  20. Juglone induces cell death of Acanthamoeba through increased production of reactive oxygen species.

    PubMed

    Jha, Bijay Kumar; Jung, Hui-Jung; Seo, Incheol; Suh, Seong-Il; Suh, Min-Ho; Baek, Won-Ki

    2015-12-01

    Juglone (5-hydroxy-1,4-naphthoquinone) is a major chemical constituent of Juglans mandshruica Maxim. Recent studies have demonstrated that juglone exhibits anti-cancer, anti-bacterial, anti-viral, and anti-parasitic properties. However, its effect against Acanthamoeba has not been defined yet. The aim of this study was to investigate the effect of juglone on Acanthamoeba. We demonstrate that juglone significantly inhibits the growth of Acanthamoeba castellanii at 3-5 μM concentrations. Juglone increased the production of reactive oxygen species (ROS) and caused cell death of A. castellanii. Inhibition of ROS by antioxidant N-acetyl-l-cysteine (NAC) restored the cell viability. Furthermore, our results show that juglone increased the uptake of mitochondrial specific dye. Collectively, these results indicate that ROS played a significant role in the juglone-induced cell death of Acanthamoeba.

  1. Juglone induces cell death of Acanthamoeba through increased production of reactive oxygen species.

    PubMed

    Jha, Bijay Kumar; Jung, Hui-Jung; Seo, Incheol; Suh, Seong-Il; Suh, Min-Ho; Baek, Won-Ki

    2015-12-01

    Juglone (5-hydroxy-1,4-naphthoquinone) is a major chemical constituent of Juglans mandshruica Maxim. Recent studies have demonstrated that juglone exhibits anti-cancer, anti-bacterial, anti-viral, and anti-parasitic properties. However, its effect against Acanthamoeba has not been defined yet. The aim of this study was to investigate the effect of juglone on Acanthamoeba. We demonstrate that juglone significantly inhibits the growth of Acanthamoeba castellanii at 3-5 μM concentrations. Juglone increased the production of reactive oxygen species (ROS) and caused cell death of A. castellanii. Inhibition of ROS by antioxidant N-acetyl-l-cysteine (NAC) restored the cell viability. Furthermore, our results show that juglone increased the uptake of mitochondrial specific dye. Collectively, these results indicate that ROS played a significant role in the juglone-induced cell death of Acanthamoeba. PMID:26358271

  2. Titanium dioxide nanoparticles increase plasma glucose via reactive oxygen species-induced insulin resistance in mice.

    PubMed

    Hu, Hailong; Guo, Qian; Wang, Changlin; Ma, Xiao; He, Hongjuan; Oh, Yuri; Feng, Yujie; Wu, Qiong; Gu, Ning

    2015-10-01

    There have been few reports about the possible toxic effects of titanium dioxide (TiO2 ) nanoparticles on the endocrine system. We explored the endocrine effects of oral administration to mice of anatase TiO2 nanoparticles (0, 64 and 320 mg kg(-1) body weight per day to control, low-dose and high-dose groups, respectively, 7 days per week for 14 weeks). TiO2 nanoparticles were characterized by scanning and transmission electron microscopy (TEM) and dynamic light scattering (DLS), and their physiological distribution was investigated by inductively coupled plasma. Biochemical analyzes included plasma glucose, insulin, heart blood triglycerides (TG), free fatty acid (FFA), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6 and reactive oxygen species (ROS)-related markers (total SOD, GSH and MDA). Phosphorylation of IRS1, Akt, JNK1, and p38 MAPK were analyzed by western blotting. Increased titanium levels were found in the liver, spleen, small intestine, kidney and pancreas. Biochemical analyzes showed that plasma glucose significantly increased whereas there was no difference in plasma insulin secretion. Increased ROS levels were found in serum and the liver, as evidenced by reduced total SOD activity and GSH level and increased MDA content. Western blotting showed that oral administration of TiO2 nanoparticles induced insulin resistance (IR) in mouse liver, shown by increased phosphorylation of IRS1 (Ser307) and reduced phosphorylation of Akt (Ser473). The pathway by which TiO2 nanoparticles increase ROS-induced IR were included in the inflammatory response and phosphokinase, as shown by increased serum levels of TNF-α and IL-6 and increased phosphorylation of JNK1 and p38 MAPK in liver. These results show that oral administration of TiO2 nanoparticles increases ROS, resulting in IR and increasing plasma glucose in mice.

  3. The maneuver search and the maneuver search trajectory framework of search heavy torpedo

    NASA Astrophysics Data System (ADS)

    Yin, Wenjin; Zhang, Jingyuan; Li, Jitao

    2016-01-01

    With the development of technology capability of submarine launching heavy torpedo and the demand of intellectualized combat, the paper raises the concept of torpedo maneuver search and analyses maneuver search opportunity. It is necessary to realize the long range heavy torpedo's maneuver search that heavy torpedo's maneuver search can cover the target's location error which results from launching platform's position precision and the target's intentional maneuver when the torpedo is launched. The technology framework of the heavy torpedo's maneuver search trajectory is set up.

  4. Increased levels of peroxisomal active oxygen-related enzymes in copper-tolerant pea plants

    SciTech Connect

    Palma, J.M.; Gomez, M.; Yanez, J.; Del Rio, L.A.

    1987-10-01

    The effect in vivo of high nutrient levels of copper (240 micromolar) on the activity of different metalloenzymes containing Cu, Mn, Fe, and Zn, distributed in chloroplasts, peroxisomes, and mitochondria, was studied in leaves of two varieties of Pisum sativum L. plants with different sensitivity to copper. The metalloenzymes studied were: cytochrome c oxidase, Mn-superoxide dismutase (Mn-SOD) and Cu,Zn-superoxide dismutase I (Cu,Zn-SOD I), for mitochondria; catalase and Mn-SOD, for peroxisomes; and isozyme Cu,Zn-SOD II for chloroplasts. The activity of mitochondrial SOD isozymes (Mn-SOD and Cu,Zn-SOD I) was very similar in Cu-tolerant and Cu-sensitive plants, whereas cytochrome c oxidase was lower in Cu-sensitive plants. Chloroplastid Cu,Zn-SOD activity was the same in the two plant varieties. In contrast, the peroxisomal Mn-SOD activity was considerably higher in Cu-tolerant than in Cu-sensitive plants, and the activity of catalase was also increased in peroxisomes of Cu-tolerant plants. The higher activities of these peroxisomal active oxygen-related enzymes in Cu-tolerant plants suggest the involvement of reactive oxygen intermediates (O/sub 2//sup -/, OH) in the mechanism of Cu lethality, and also imply a function for peroxisomal Mn-SOD in the molecular mechanisms of plant tolerance to Cu in Pisum sativum L.

  5. An Independent and Coordinated Criterion for Kinematic Aircraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Narkawicz, Anthony J.; Munoz, Cesar A.; Hagen, George

    2014-01-01

    This paper proposes a mathematical definition of an aircraft-separation criterion for kinematic-based horizontal maneuvers. It has been formally proved that kinematic maneu- vers that satisfy the new criterion are independent and coordinated for repulsiveness, i.e., the distance at closest point of approach increases whether one or both aircraft maneuver according to the criterion. The proposed criterion is currently used in NASA's Airborne Coordinated Resolution and Detection (ACCoRD) set of tools for the design and analysis of separation assurance systems.

  6. Active Control of Solar Array Dynamics During Spacecraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Ross, Brant A.; Woo, Nelson; Kraft, Thomas G.; Blandino, Joseph R.

    2016-01-01

    Recent NASA mission plans require spacecraft to undergo potentially significant maneuvers (or dynamic loading events) with large solar arrays deployed. Therefore there is an increased need to understand and possibly control the nonlinear dynamics in the spacecraft system during such maneuvers. The development of a nonlinear controller is described. The utility of using a nonlinear controller to reduce forces and motion in a solar array wing during a loading event is demonstrated. The result is dramatic reductions in system forces and motion during a 10 second loading event. A motion curve derived from the simulation with the closed loop controller is used to obtain similar benefits with a simpler motion control approach.

  7. Decrease in the etch rate of polymers in the oxygen afterglow with increasing gas flow rate

    NASA Technical Reports Server (NTRS)

    Lerner, N. R.; Wydeven, T.

    1988-01-01

    This paper reports the variation of the etch rate of polymers in the afterglow of a radio frequency discharge in oxygen as a function of total flow rate in the range 2-10 cu cm (STP)/min. The measurements were made at ambient temperature with the O(P-3) concentration held essentially constant. Results are reported on three polymers: cis-polybutadiene, a polybutadiene with 33 percent 1,2 double bonds, and a polybutadiene with 40 percent 1,2 double bonds. It has been observed that the etch rate of these polymers decreases significantly with increasing flow rate, strongly suggesting that the vapor-phase products of polymer degradation contribute to the degradation process.

  8. Elevated Cytoplasmic Free Zinc and Increased Reactive Oxygen Species Generation in the Context of Brain Injury.

    PubMed

    Stork, Christian J; Li, Yang V

    2016-01-01

    Intracellular zinc release and the generation of reactive oxygen species (ROS) have been reported to be common ingredients in numerous toxic signaling mechanisms in neurons. A key source for intracellular zinc release is its liberation from metallothionein-III (MT-III). MT-III binds and regulates intracellular zinc levels under physiological conditions, but the zinc-binding thiols readily react with certain ROS and reactive nitrogen species (RNS) to result in intracellular zinc liberation. Liberated zinc induces ROS and RNS generation by multiple mechanisms, including the induction of mitochondrial ROS production, and also promotes ROS formation outside the mitochondria by interaction with the enzymes NADPH oxidase and 12-lipoxygenase. Of particular relevance to neuronal injury in the context of ischemia and prolonged seizures, the positive feedback cycle between ROS/RNS generation and increasing zinc liberation will be examined.

  9. Polyglutamine expansion inhibits respiration by increasing reactive oxygen species in isolated mitochondria

    SciTech Connect

    Puranam, Kasturi L.; Wu, Guanghong; Strittmatter, Warren J.; Burke, James R. . E-mail: james.burke@duke.edu

    2006-03-10

    Huntington's disease results from expansion of the polyglutamine (PolyQ) domain in the huntingtin protein. Although the cellular mechanism by which pathologic-length PolyQ protein causes neurodegeneration is unclear, mitochondria appear central in pathogenesis. We demonstrate in isolated mitochondria that pathologic-length PolyQ protein directly inhibits ADP-dependent (state 3) mitochondrial respiration. Inhibition of mitochondrial respiration by PolyQ protein is not due to reduction in the activities of electron transport chain complexes, mitochondrial ATP synthase, or the adenine nucleotide translocase. We show that pathologic-length PolyQ protein increases the production of reactive oxygen species in isolated mitochondria. Impairment of state 3 mitochondrial respiration by PolyQ protein is reversed by addition of the antioxidants N-acetyl-L-cysteine or cytochrome c. We propose a model in which pathologic-length PolyQ protein directly inhibits mitochondrial function by inducing oxidative stress.

  10. Increased oxygenation of the cerebral prefrontal cortex prior to the onset of voluntary exercise in humans.

    PubMed

    Matsukawa, Kanji; Ishii, Kei; Liang, Nan; Endo, Kana; Ohtani, Ryo; Nakamoto, Tomoko; Wakasugi, Rie; Kadowaki, Akito; Komine, Hidehiko

    2015-09-01

    To determine whether output from the forebrain (termed central command) may descend early enough to increase cardiac and renal sympathetic outflows at the onset of voluntary exercise, we examined the changes in regional tissue blood flows of bilateral prefrontal cortices with near-infrared spectroscopy, precisely identifying the onset of voluntary ergometer 30-s exercise at 41 ± 2% of the maximal exercise intensity in humans. Prefrontal oxygenated-hemoglobin (Oxy-Hb) concentration was measured as index of regional blood flow unless deoxygenated-hemoglobin concentration remained unchanged. Prefrontal Oxy-Hb concentration increased significantly (P < 0.05) 5 s prior to the onset of exercise with arbitrary start, whereas such increase in prefrontal Oxy-Hb was absent before exercise abruptly started by a verbal cue. Furthermore, the increase in prefrontal Oxy-Hb observed at the initial 15-s period of exercise was greater with arbitrary start than cued start. The prefrontal Oxy-Hb, thereafter, decreased during the later period of exercise, irrespective of either arbitrary or cued start. The reduction in prefrontal Oxy-Hb had the same time course and response magnitude as that during motor-driven passive exercise. Cardiac output increased at the initial period of exercise, whereas arterial blood pressure and total peripheral resistance decreased. The depressor response was more pronounced (P < 0.05) with arbitrary start than cued start. Taken together, it is suggested that the increase in prefrontal Oxy-Hb observed prior to the onset of voluntary exercise may be in association with central command, while the later decrease in the Oxy-Hb during exercise may be in association with feedback stimulated by mechanical limb motion.

  11. Increasing Oxygen Radicals and Water Temperature Select for Toxic Microcystis sp

    PubMed Central

    Dziallas, Claudia; Grossart, Hans-Peter

    2011-01-01

    Pronounced rises in frequency of toxic cyanobacterial blooms are recently observed worldwide, particularly when temperatures increase. Different strains of cyanobacterial species vary in their potential to produce toxins but driving forces are still obscure. Our study examines effects of hydrogen peroxide on toxic and non-toxic (including a non-toxic mutant) strains of M. aeruginosa. Here we show that hydrogen peroxide diminishes chlorophyll a content and growth of cyanobacteria and that this reduction is significantly lower for toxic than for non-toxic strains. This indicates that microcystins protect from detrimental effects of oxygen radicals. Incubation of toxic and non-toxic strains of M. aeruginosa with other bacteria or without (axenic) at three temperatures (20, 26 and 32°C) reveals a shift toward toxic strains at higher temperatures. In parallel to increases in abundance of toxic (i.e. toxin gene possessing) strains and their actual toxin expression, concentrations of microcystins rise with temperature, when amounts of radicals are expected to be enhanced. Field samples from three continents support the influence of radicals and temperature on toxic potential of M. aeruginosa. Our results imply that global warming will significantly increase toxic potential and toxicity of cyanobacterial blooms which has strong implications for socio-economical assessments of global change. PMID:21980492

  12. Increasing oxygen radicals and water temperature select for toxic Microcystis sp.

    PubMed

    Dziallas, Claudia; Grossart, Hans-Peter

    2011-01-01

    Pronounced rises in frequency of toxic cyanobacterial blooms are recently observed worldwide, particularly when temperatures increase. Different strains of cyanobacterial species vary in their potential to produce toxins but driving forces are still obscure. Our study examines effects of hydrogen peroxide on toxic and non-toxic (including a non-toxic mutant) strains of M. aeruginosa. Here we show that hydrogen peroxide diminishes chlorophyll a content and growth of cyanobacteria and that this reduction is significantly lower for toxic than for non-toxic strains. This indicates that microcystins protect from detrimental effects of oxygen radicals. Incubation of toxic and non-toxic strains of M. aeruginosa with other bacteria or without (axenic) at three temperatures (20, 26 and 32°C) reveals a shift toward toxic strains at higher temperatures. In parallel to increases in abundance of toxic (i.e. toxin gene possessing) strains and their actual toxin expression, concentrations of microcystins rise with temperature, when amounts of radicals are expected to be enhanced. Field samples from three continents support the influence of radicals and temperature on toxic potential of M. aeruginosa. Our results imply that global warming will significantly increase toxic potential and toxicity of cyanobacterial blooms which has strong implications for socio-economical assessments of global change.

  13. Oxidized low density lipoprotein increases acetylcholinesterase activity correlating with reactive oxygen species production.

    PubMed

    Yamchuen, Panit; Aimjongjun, Sathid; Limpeanchob, Nanteetip

    2014-12-01

    Hyperlipidemia, low density lipoproteins (LDL) and their oxidized forms, and oxidative stress are suspected to be a key combination in the onset of AD and acetylcholinesterase (AChE) plays a part in this pathology. The present study aimed to link these parameters using differentiated SH-SY5Y human neuroblastoma cells in culture. Both mildly and fully oxidized human LDL (mox- and fox-LDL), but not native (non-oxidized) LDL were cytotoxic in dose- and time-dependent patterns and this was accompanied by an increased production of intracellular reactive oxygen species (ROS). Oxidized LDL (10-200 μg/mL) augmented AChE activity after 4 and 24h treatments, respectively while the native LDL was without effect. The increased AChE with oxidized LDLs was accompanied by a proportionate increase in intracellular ROS formation (R=0.904). These findings support the notion that oxidized LDLs are cytotoxic and that their action on AChE may reduce central cholinergic transmission in AD and affirm AChE as a continued rational for anticholinesterase therapy but in conjunction with antioxidant/antihyperlipidemic cotreatments.

  14. Orbital maneuvers and space rendezvous

    NASA Astrophysics Data System (ADS)

    Butikov, Eugene I.

    2015-12-01

    Several possibilities of launching a space vehicle from the orbital station are considered and compared. Orbital maneuvers discussed in the paper can be useful in designing a trajectory for a specific space mission. The relative motion of orbiting bodies is investigated on examples of spacecraft rendezvous with the space station that stays in a circular orbit around the Earth. An elementary approach is illustrated by an accompanying simulation computer program and supported by a mathematical treatment based on fundamental laws of physics and conservation laws. Material is appropriate for engineers and other personnel involved in space exploration, undergraduate and graduate students studying classical physics and orbital mechanics.

  15. Optical gradient force assist maneuver.

    PubMed

    Artusio-Glimpse, Alexandra B; Wirth, Jacob H; Swartzlander, Grover A

    2016-09-01

    We describe an energy transfer process whereby a moving particle loses (or gains) kinetic energy upon interacting with the moving optical potential of a swept beam of light. This approach is akin to a gravitational assist maneuver for interplanetary satellite propulsion. Special consideration is given to the stopping condition. For analytical convenience, we examine the Rayleigh scattering regime, providing examples at small and large scattering angles. A 5% uncertainty in the initial particle speed and position has negligible effect on the slowing/speeding ability when the beam size is much larger than the particle. PMID:27607993

  16. Increase in tracheal investment with beetle size supports hypothesis of oxygen limitation on insect gigantism.

    PubMed

    Kaiser, Alexander; Klok, C Jaco; Socha, John J; Lee, Wah-Keat; Quinlan, Michael C; Harrison, Jon F

    2007-08-01

    Recent studies have suggested that Paleozoic hyperoxia enabled animal gigantism, and the subsequent hypoxia drove a reduction in animal size. This evolutionary hypothesis depends on the argument that gas exchange in many invertebrates and skin-breathing vertebrates becomes compromised at large sizes because of distance effects on diffusion. In contrast to vertebrates, which use respiratory and circulatory systems in series, gas exchange in insects is almost exclusively determined by the tracheal system, providing a particularly suitable model to investigate possible limitations of oxygen delivery on size. In this study, we used synchrotron x-ray phase-contrast imaging to visualize the tracheal system and quantify its dimensions in four species of darkling beetles varying in mass by 3 orders of magnitude. We document that, in striking contrast to the pattern observed in vertebrates, larger insects devote a greater fraction of their body to the respiratory system, as tracheal volume scaled with mass1.29. The trend is greatest in the legs; the cross-sectional area of the trachea penetrating the leg orifice scaled with mass1.02, whereas the cross-sectional area of the leg orifice scaled with mass0.77. These trends suggest the space available for tracheae within the leg may ultimately limit the maximum size of extant beetles. Because the size of the tracheal system can be reduced when oxygen supply is increased, hyperoxia, as occurred during late Carboniferous and early Permian, may have facilitated the evolution of giant insects by allowing limbs to reach larger sizes before the tracheal system became limited by spatial constraints.

  17. Acrolein activates matrix metalloproteinases by increasing reactive oxygen species in macrophages

    SciTech Connect

    O'Toole, Timothy E. Zheng Yuting; Hellmann, Jason; Conklin, Daniel J.; Barski, Oleg; Bhatnagar, Aruni

    2009-04-15

    Acrolein is a ubiquitous component of environmental pollutants such as automobile exhaust, cigarette, wood, and coal smoke. It is also a natural constituent of several foods and is generated endogenously during inflammation or oxidation of unsaturated lipids. Because increased inflammation and episodic exposure to acrolein-rich pollutants such as traffic emissions or cigarette smoke have been linked to acute myocardial infarction, we examined the effects of acrolein on matrix metalloproteinases (MMPs), which destabilize atherosclerotic plaques. Our studies show that exposure to acrolein resulted in the secretion of MMP-9 from differentiated THP-1 macrophages. Acrolein-treatment of macrophages also led to an increase in reactive oxygen species (ROS), free intracellular calcium ([Ca{sup 2+}]{sub i}), and xanthine oxidase (XO) activity. ROS production was prevented by allopurinol, but not by rotenone or apocynin and by buffering changes in [Ca{sup 2+}]{sub I} with BAPTA-AM. The increase in MMP production was abolished by pre-treatment with the antioxidants Tiron and N-acetyl cysteine (NAC) or with the xanthine oxidase inhibitors allopurinol or oxypurinol. Finally, MMP activity was significantly stimulated in aortic sections from apoE-null mice containing advanced atherosclerotic lesions after exposure to acrolein ex vivo. These observations suggest that acrolein exposure results in MMP secretion from macrophages via a mechanism that involves an increase in [Ca{sup 2+}]{sub I}, leading to xanthine oxidase activation and an increase in ROS production. ROS-dependent activation of MMPs by acrolein could destabilize atherosclerotic lesions during brief episodes of inflammation or pollutant exposure.

  18. Increase in maximal oxygen uptake following 2-week walk training with blood flow occlusion in athletes.

    PubMed

    Park, Saejong; Kim, Jong Kyung; Choi, Hyun Min; Kim, Hyun Gook; Beekley, Matthew D; Nho, Hosung

    2010-07-01

    Walk training with blood flow occlusion (OCC-walk) leads to muscle hypertrophy; however, cardiorespiratory endurance in response to OCC-walk is unknown. Ischemia enhances the adaptation to endurance training such as increased maximal oxygen uptake (VO₂(max)) and muscle glycogen content. Thus, we investigated the effects of an OCC-walk on cardiorespiratory endurance, anaerobic power, and muscle strength in elite athletes. College basketball players participated in walk training with (n = 7) and without (n = 5) blood flow occlusion. Five sets of a 3-min walk (4-6 km/h at 5% grade) and a 1-min rest between the walks were performed twice a day, 6 days a week for 2 weeks. Two-way ANOVA with repeated measures (groups x time) was utilized (P < 0.05). Interactions were found in VO₂(max) (P = 0.011) and maximal minute ventilation (VE(max); P = 0.019). VO₂(max) (11.6%) and VE(max) (10.6%) were increased following the OCC-walk. For the cardiovascular adaptations of the OCC-walk, hemodynamic parameters such as stroke volume (SV) and heart rate (HR) at rest and during OCC-walk were compared between the first and the last OCC-walk sessions. Although no change in hemodynamics was found at rest, during the last OCC-walk session SV was increased in all five sets (21.4%) and HR was decreased in the third (12.3%) and fifth (15.0%) sets. With anaerobic power an interaction was found in anaerobic capacity (P = 0.038) but not in peak power. Anaerobic capacity (2.5%) was increased following the OCC-walk. No interaction was found in muscle strength. In conclusion, the 2-week OCC-walk significantly increases VO₂(max) and VE(max) in athletes. The OCC-walk training might be used in the rehabilitation for athletes who intend to maintain or improve endurance.

  19. Oxygen increases ductus arteriosus smooth muscle cytosolic calcium via release of calcium from inositol triphosphate-sensitive stores.

    PubMed

    Keck, Maggie; Resnik, Ernesto; Linden, Bradley; Anderson, Franklin; Sukovich, David J; Herron, Jean; Cornfield, David N

    2005-05-01

    In utero, blood shunts away from the lungs via the ductus arteriosus (DA) and the foramen ovale. After birth, the DA closes concomitant with increased oxygen tension. The present experimental series tests the hypothesis that oxygen directly increases DA smooth muscle cell (SMC) cytosolic calcium ([Ca(2+)](i)) through inactivation of a K(+) channel, membrane depolarization, and entry of extracellular calcium. To test the hypothesis, DA SMC were isolated from late-gestation fetal lambs and grown to subconfluence in primary culture in low oxygen tension (25 Torr). DA SMC were loaded with the calcium-sensitive fluorophore fura-2 under low oxygen tension conditions and studied using microfluorimetry while oxygen tension was acutely increased (120 Torr). An acute increase in oxygen tension progressively increased DA SMC [Ca(2+)](i) by 11.7 +/- 1.4% over 40 min. The effect of acute normoxia on DA SMC [Ca(2+)](i) was mimicked by pharmacological blockade of the voltage-sensitive K(+) channel. Neither removal of extracellular calcium nor voltage-operated calcium channel blockade prevented the initial increase in DA SMC [Ca(2+)](i). Manganese quenching experiments demonstrated that acute normoxia initially decreases the rate of extracellular calcium entry. Pharmacological blockade of inositol triphosphate-sensitive, but not ryanodine-sensitive, intracellular calcium stores prevented the oxygen-induced increase in [Ca(2+)](i). Endothelin increased [Ca(2+)](i) in acutely normoxic, but not hypoxic, DA SMC. Thus acute normoxia 1) increases DA SMC [Ca(2+)](i) via release of calcium from intracellular calcium stores, and subsequent entry of extracellular calcium, and 2) potentiates the effect of contractile agonists. Prolonged patency of the DA may result from disordered intracellular calcium homeostasis.

  20. Fish oil increases mitochondrial phospholipid unsaturation, upregulating reactive oxygen species and apoptosis in rat colonocytes

    NASA Technical Reports Server (NTRS)

    Hong, Mee Young; Chapkin, Robert S.; Barhoumi, Rola; Burghardt, Robert C.; Turner, Nancy D.; Henderson, Cara E.; Sanders, Lisa M.; Fan, Yang-Yi; Davidson, Laurie A.; Murphy, Mary E.; Spinka, Christine M.; Carroll, Raymond J.; Lupton, Joanne R.

    2002-01-01

    We have shown that a combination of fish oil (high in n-3 fatty acids) with the butyrate-producing fiber pectin, upregulates apoptosis in colon cells exposed to the carcinogen azoxymethane, protecting against colon tumor development. We now hypothesize that n-3 fatty acids prime the colonocytes such that butyrate can initiate apoptosis. To test this, 30 Sprague-Dawley rats were provided with diets differing in the fatty acid composition (corn oil, fish oil or a purified fatty acid ethyl ester diet). Intact colon crypts were exposed ex vivo to butyrate, and analyzed for reactive oxygen species (ROS), mitochondrial membrane potential (MMP), translocation of cytochrome C to the cytosol, and caspase-3 activity (early events in apoptosis). The fatty acid composition of the three major mitochondrial phospholipids was also determined, and an unsaturation index calculated. The unsaturation index in cardiolipin was correlated with ROS levels (R = 0.99; P = 0.02). When colon crypts from fish oil and FAEE-fed rats were exposed to butyrate, MMP decreased (P = 0.041); and translocation of cytochrome C to the cytosol (P = 0.037) and caspase-3 activation increased (P = 0.032). The data suggest that fish oil may prime the colonocytes for butyrate-induced apoptosis by enhancing the unsaturation of mitochondrial phospholipids, especially cardiolipin, resulting in an increase in ROS and initiating apoptotic cascade.

  1. A blood-oxygenation-dependent increase in blood viscosity due to a static magnetic field.

    PubMed

    Yamamoto, Toru; Nagayama, Yuki; Tamura, Mamoru

    2004-07-21

    As the magnetic field of widely used MR scanners is one of the strongest magnetic fields to which people are exposed, the biological influence of the static magnetic field of MR scanners is of great concern. One magnetic interaction in biological subjects is the magnetic torque on the magnetic moment induced by biomagnetic substances. The red blood cell is a major biomagnetic substance, and the blood flow may be influenced by the magnetic field. However, the underlying mechanisms have been poorly understood. To examine the mechanisms of the magnetic influence on blood viscosity, we measured the time for blood to fall through a glass capillary inside and outside a 1.5 T MR scanner. Our in vitro results showed that the blood viscosity significantly increased in a 1.5 T MR scanner, and also clarified the mechanism of the interaction between red blood cells and the external magnetic field. Notably, the blood viscosity increased depending on blood oxygenation and the shear rate of the blood flow. Thus, our findings suggest that even a 1.5 T magnetic field may modulate blood flow.

  2. Increased Reactive Oxygen Species Formation and Oxidative Stress in Rheumatoid Arthritis

    PubMed Central

    Mateen, Somaiya; Moin, Shagufta; Khan, Abdul Qayyum; Zafar, Atif; Fatima, Naureen

    2016-01-01

    Background Rheumatoid arthritis (RA) is an autoimmune inflammatory disorder. Highly reactive oxygen free radicals are believed to be involved in the pathogenesis of the disease. In this study, RA patients were sub-grouped depending upon the presence or absence of rheumatoid factor, disease activity score and disease duration. RA Patients (120) and healthy controls (53) were evaluated for the oxidant—antioxidant status by monitoring ROS production, biomarkers of lipid peroxidation, protein oxidation and DNA damage. The level of various enzymatic and non-enzymatic antioxidants was also monitored. Correlation analysis was also performed for analysing the association between ROS and various other parameters. Methods Intracellular ROS formation, lipid peroxidation (MDA level), protein oxidation (carbonyl level and thiol level) and DNA damage were detected in the blood of RA patients. Antioxidant status was evaluated by FRAP assay, DPPH reduction assay and enzymatic (SOD, catalase, GST, GR) and non-enzymatic (vitamin C and GSH) antioxidants. Results RA patients showed a higher ROS production, increased lipid peroxidation, protein oxidation and DNA damage. A significant decline in the ferric reducing ability, DPPH radical quenching ability and the levels of antioxidants has also been observed. Significant correlation has been found between ROS and various other parameters studied. Conclusion RA patients showed a marked increase in ROS formation, lipid peroxidation, protein oxidation, DNA damage and decrease in the activity of antioxidant defence system leading to oxidative stress which may contribute to tissue damage and hence to the chronicity of the disease. PMID:27043143

  3. Hyberbaric oxygen increases atresia in normal & steroid induced PCO rat ovaries

    PubMed Central

    2012-01-01

    Background In this study, we investigated the effect of hyperbaric oxygen therapy (HBOT) on the morphology of estradiol valerate (EV) induced polycystic ovary (PCO) to find a new treatment modality for improvement of PCO. Methods The rats were divided into four groups. Group1, control; group 2, PCO group; group 3, PCO with HBOT group and group 4, normal ovary with HBOT. PCO was induced by a single intramuscular injection of 4 mg EV in adult cycling rats. Other rats with normal ovaries had oil injection as placebo. HBOT was applied to third and fourth groups for six weeks. Histopathologic evaluation of ovaries of all groups were performed & compared. Results Six weeks of HBOT was resulted in increase in follicular atresia, decrease in the number of primary, secondary, tertiary follicles and decrease in the number of fresh corpus luteum in normal rat ovary. HBOT on polycystic rat ovary, resulted in significant increase in atretic follicles which were already present. Conclusions HBOT of six weeks itself, changed ovarian morphology in favor of atresia both in PCO group and control group. This result of aggravated follicular atresia after HBOT on EV induced PCO may be due to long-term exposure in our protocol which with this state seems to be inapplicable in the improvement of PCO morphology. PMID:22309835

  4. Optimal Electrodynamic Tether Phasing Maneuvers

    NASA Technical Reports Server (NTRS)

    Bitzer, Matthew S.; Hall, Christopher D.

    2007-01-01

    We study the minimum-time orbit phasing maneuver problem for a constant-current electrodynamic tether (EDT). The EDT is assumed to be a point mass and the electromagnetic forces acting on the tether are always perpendicular to the local magnetic field. After deriving and non-dimensionalizing the equations of motion, the only input parameters become current and the phase angle. Solution examples, including initial Lagrange costates, time of flight, thrust plots, and thrust angle profiles, are given for a wide range of current magnitudes and phase angles. The two-dimensional cases presented use a non-tilted magnetic dipole model, and the solutions are compared to existing literature. We are able to compare similar trajectories for a constant thrust phasing maneuver and we find that the time of flight is longer for the constant thrust case with similar initial thrust values and phase angles. Full three-dimensional solutions, which use a titled magnetic dipole model, are also analyzed for orbits with small inclinations.

  5. Cassini-Huygens maneuver automation for navigation

    NASA Technical Reports Server (NTRS)

    Goodson, Troy; Attiyah, Amy; Buffington, Brent; Hahn, Yungsun; Pojman, Joan; Stavert, Bob; Strange, Nathan; Stumpf, Paul; Wagner, Sean; Wolff, Peter; Wong, Mau

    2006-01-01

    Many times during the Cassini-Huygens mission to Saturn, propulsive maneuvers must be spaced so closely together that there isn't enough time or workforce to execute the maneuver-related software manually, one subsystem at a time. Automation is required. Automating the maneuver design process has involved close cooperation between teams. We present the contribution from the Navigation system. In scope, this includes trajectory propagation and search, generation of ephemerides, general tasks such as email notification and file transfer, and presentation materials. The software has been used to help understand maneuver optimization results, Huygens probe delivery statistics, and Saturn ring-plane crossing geometry. The Maneuver Automation Software (MAS), developed for the Cassini-Huygens program enables frequent maneuvers by handling mundane tasks such as creation of deliverable files, file delivery, generation and transmission of email announcements, generation of presentation material and other supporting documentation. By hand, these tasks took up hours, if not days, of work for each maneuver. Automated, these tasks may be completed in under an hour. During the cruise trajectory the spacing of maneuvers was such that development of a maneuver design could span about a month, involving several other processes in addition to that described, above. Often, about the last five days of this process covered the generation of a final design using an updated orbit-determination estimate. To support the tour trajectory, the orbit determination data cut-off of five days before the maneuver needed to be reduced to approximately one day and the whole maneuver development process needed to be reduced to less than a week..

  6. Increased retinal oxygen supply following pan-retinal photocoagulation and vitrectomy and lensectomy.

    PubMed Central

    Stefansson, E; Landers, M B; Wolbarsht, M L

    1981-01-01

    Panretinal photocoagulation as well as vitrectomy are the main treatment modalities for diabetic and other proliferative retinopathies. We show that both treatments introduce a new source of oxygen to the inner retina and propose that their efficacy in controlling the retinopathy results from their effect on the oxygenation of the inner retina. Panretinal photocoagulation reduces the oxygen consumption of the outer retina and allows more oxygen to diffuse to the inner retina from the choroid. Vitrectomy/lensectomy on the other hand allows aqueous humor to flow back to the retina and give oxygen to the inner retina which normally has a lower PO2 than aqueous humor. This causes the PO2 in aqueous humor to fall. Images FIGURE 1 A FIGURE 1 B FIGURE 1 C FIGURE 1 D FIGURE 4 A FIGURE 4 B PMID:7200671

  7. Normative data on phases of the Valsalva maneuver

    NASA Technical Reports Server (NTRS)

    Denq, J. C.; O'Brien, P. C.; Low, P. A.

    1998-01-01

    The phases of the Valsalva maneuver have well-known pathophysiology, and are used in the evaluation of adrenergic function. Because scant normative data is available, we have evaluated normative data for the Valsalva maneuver in control subjects. The patient, supine, performed the Valsalva maneuver maintaining an expiratory pressure of 40 mm Hg for 15 seconds. We reviewed 188 Valsalva maneuver recordings of normal control subjects, and recordings were excluded if two reproducible recordings were not obtained, or if expiratory pressure was <30 mm Hg or < 10 seconds. One hundred and three recordings were acceptable for analysis; 47 female and 56 male subjects, age in years (mean +/- SD) was 52.2+/-17.3 and 44.8+/-17.3, respectively. The association of expiratory pressure with age (P < 0.001) and gender ( P < 0.001) was complex, expressed as a parabola in both men and women, but resulted in phases I and III that were not significantly different. An increase in age resulted in a progressively more negative phase II_E (P < 0.05) and attenuation of phase II_L (P < 0.01). An increase in supine blood pressure resulted in a significantly more negative phase II_E (P < 0.001) and a lower phase IV. Phase IV is unaffected by age and gender.

  8. 14 CFR 23.423 - Maneuvering loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Balancing Surfaces § 23.423 Maneuvering loads. Each horizontal surface and its supporting structure, and the...-down pitching conditions is the sum of the balancing loads at V and the specified value of the normal... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maneuvering loads. 23.423 Section...

  9. 14 CFR 23.423 - Maneuvering loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Balancing Surfaces § 23.423 Maneuvering loads. Each horizontal surface and its supporting structure, and the...-down pitching conditions is the sum of the balancing loads at V and the specified value of the normal... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maneuvering loads. 23.423 Section...

  10. 46 CFR 109.564 - Maneuvering characteristics.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Maneuvering characteristics. 109.564 Section 109.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.564 Maneuvering characteristics. (a) The master or person in charge of...

  11. 46 CFR 109.564 - Maneuvering characteristics.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Maneuvering characteristics. 109.564 Section 109.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.564 Maneuvering characteristics. (a) The master or person in charge of...

  12. 46 CFR 109.564 - Maneuvering characteristics.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Maneuvering characteristics. 109.564 Section 109.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.564 Maneuvering characteristics. (a) The master or person in charge of...

  13. 46 CFR 109.564 - Maneuvering characteristics.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Maneuvering characteristics. 109.564 Section 109.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.564 Maneuvering characteristics. (a) The master or person in charge of...

  14. 46 CFR 109.564 - Maneuvering characteristics.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Maneuvering characteristics. 109.564 Section 109.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.564 Maneuvering characteristics. (a) The master or person in charge of...

  15. Mitohormesis: Promoting Health and Lifespan by Increased Levels of Reactive Oxygen Species (ROS)

    PubMed Central

    Ristow, Michael; Schmeisser, Kathrin

    2014-01-01

    Increasing evidence indicates that reactive oxygen species (ROS), consisting of superoxide, hydrogen peroxide, and multiple others, do not only cause oxidative stress, but rather may function as signaling molecules that promote health by preventing or delaying a number of chronic diseases, and ultimately extend lifespan. While high levels of ROS are generally accepted to cause cellular damage and to promote aging, low levels of these may rather improve systemic defense mechanisms by inducing an adaptive response. This concept has been named mitochondrial hormesis or mitohormesis. We here evaluate and summarize more than 500 publications from current literature regarding such ROS-mediated low-dose signaling events, including calorie restriction, hypoxia, temperature stress, and physical activity, as well as signaling events downstream of insulin/IGF-1 receptors, AMP-dependent kinase (AMPK), target-of-rapamycin (TOR), and lastly sirtuins to culminate in control of proteostasis, unfolded protein response (UPR), stem cell maintenance and stress resistance. Additionally, consequences of interfering with such ROS signals by pharmacological or natural compounds are being discussed, concluding that particularly antioxidants are useless or even harmful. PMID:24910588

  16. Cycling exercise to resist electrically stimulated antagonist increases oxygen uptake in males: pilot study.

    PubMed

    Matsuse, Hiroo; Shiba, Naoto; Takano, Yoshio; Yamada, Shin; Ohshima, Hiroshi; Tagawa, Yoshihiko

    2013-01-01

    A hybrid training system (HTS) has been developed as the combined application of electrical stimulation (ES) and volitional contractions (VC), using electrically stimulated eccentric antagonist muscle contractions as a resistance to voluntary agonist muscle contractions. The purpose of the present study is to compare the metabolic cost between cycling exercise using HTS as added resistance (HTC) and unloaded cycling exercise (ULC). Twelve male subjects exercised on a leg cycle ergometer. After 5 min rest and 5 min warm up, they performed ULC for 5 min or HTC for 5 min. During rest and each exercise, the steady state of oxygen uptake (VO2), carbon dioxide output (VCO2), expired ventilation (VE), respiratory exchange ratio (RER), and heart rate (HR) were measured. The values of VO2, VCO2, VE, and HR during HTC were significantly greater than during ULC (p < 0.05). Relative VO2 was 16.7% +/- 2.1% of peak VO2 during ULC, and it was 21.1% +/- 3.4% during HTC. However, there was no significant difference in RER between ULC and HTC. These findings indicate that the combined application of VC and ES could lead to a greater increase in metabolic cost. HTS seems to be applicable as a resistance of motion. PMID:23934874

  17. Heterozygous Mutation of Opa1 in Drosophila Shortens Lifespan Mediated through Increased Reactive Oxygen Species Production

    PubMed Central

    Tang, Sha; Le, Phung Khanh; Tse, Stephanie; Wallace, Douglas C.; Huang, Taosheng

    2009-01-01

    Optic atrophy 1 (OPA1) is a dynamin-like GTPase located in the inner mitochondrial membrane and mutations in OPA1 are associated with autosomal dominant optic atrophy (DOA). OPA1 plays important roles in mitochondrial fusion, cristae remodeling and apoptosis. Our previous study showed that dOpa1 mutation caused elevated reactive oxygen species (ROS) production and resulted in damage and death of the cone and pigment cells in Drosophila eyes. Since ROS-induced oxidative damage to the cells is one of the primary causes of aging, in this study, we examined the effects of heterozygous dOpa1 mutation on the lifespan. We found that heterozygous dOpa1 mutation caused shortened lifespan, increased susceptibility to oxidative stress and elevated production of ROS in the whole Drosophila. Antioxidant treatment partially restored lifespan in the male dOpa1 mutants, but had no effects in the females. Heterozygous dOpa1 mutation caused an impairment of respiratory chain complex activities, especially complexes II and III, and reversible decreased aconitase activity. Heterozygous dOpa1 mutation is also associated with irregular and dysmorphic mitochondria in the muscle. Our results, for the first time, demonstrate the important role of OPA1 in aging and lifespan, which is most likely mediated through augmented ROS production. PMID:19221591

  18. Maneuver Classification for Aircraft Fault Detection

    NASA Technical Reports Server (NTRS)

    Oza, Nikunj C.; Tumer, Irem Y.; Tumer, Kagan; Huff, Edward M.

    2003-01-01

    Automated fault detection is an increasingly important problem in aircraft maintenance and operation. Standard methods of fault detection assume the availability of either data produced during all possible faulty operation modes or a clearly-defined means to determine whether the data provide a reasonable match to known examples of proper operation. In the domain of fault detection in aircraft, identifying all possible faulty and proper operating modes is clearly impossible. We envision a system for online fault detection in aircraft, one part of which is a classifier that predicts the maneuver being performed by the aircraft as a function of vibration data and other available data. To develop such a system, we use flight data collected under a controlled test environment, subject to many sources of variability. We explain where our classifier fits into the envisioned fault detection system as well as experiments showing the promise of this classification subsystem.

  19. Tactical Maneuvering Using Immunized Sequence Selection

    NASA Technical Reports Server (NTRS)

    Kaneshige, John; KrishnaKumar, K.; Shung, Felix

    2003-01-01

    This paper describes a tactical maneuvering system that uses an artificial immune system based approach for selecting maneuver sequences. This approach combines the problem solving abilities of genetic algorithms with the memory retention characteristics of an immune system. Of significant importance here is the fact that the tactical maneuvering system can make time-critical decisions to accomplish near-term objectives within a dynamic environment. These objectives can be received from a human operator, autonomous executive, or various flight planning specialists. Simulation tests were performed using a high performance military aircraft model. Results demonstrate the potential of using immunized sequence selection in order to accomplish tactical maneuvering objectives ranging from flying to a location while avoiding unforeseen obstacles, to performing relative positioning in support of air combat maneuvering.

  20. Atmospheric maneuvering during Martian entry

    NASA Astrophysics Data System (ADS)

    Tauber, Michael E.; Bowles, Jeffrey V.; Yang, Lily

    A comparative-advantages study is made of two different Martian atmospheric entry maneuvers, on the basis of calculation results for the case of a vehicle with a maximum L/D ratio of 2.3. Entries from a highly elliptical Martian orbit at 5 km/sec are more difficult than those from a lower altitude and speed orbit at 3.5 km/sec, due to their more stringent guidance requirements. Efforts to reduce the deceleration for the higher speed entry by lift-modulation achieved a 40-percent reduction, but at the cost of a 50-percent decrease in lateral range. The lower-speed entry's gliding trajectory is noted to encounter a far more benign atmospheric environment.

  1. Energy Index For Aircraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Chidester, Thomas R. (Inventor); Lynch, Robert E. (Inventor); Lawrence, Robert E. (Inventor); Amidan, Brett G. (Inventor); Ferryman, Thomas A. (Inventor); Drew, Douglas A. (Inventor); Ainsworth, Robert J. (Inventor); Prothero, Gary L. (Inventor); Romanowski, Tomothy P. (Inventor); Bloch, Laurent (Inventor)

    2006-01-01

    Method and system for analyzing, separately or in combination, kinetic energy and potential energy and/or their time derivatives, measured or estimated or computed, for an aircraft in approach phase or in takeoff phase, to determine if the aircraft is or will be put in an anomalous configuration in order to join a stable approach path or takeoff path. A 3 reference value of kinetic energy andor potential energy (or time derivatives thereof) is provided, and a comparison index .for the estimated energy and reference energy is computed and compared with a normal range of index values for a corresponding aircraft maneuver. If the computed energy index lies outside the normal index range, this phase of the aircraft is identified as anomalous, non-normal or potentially unstable.

  2. Manned maneuvering unit: User's guide

    NASA Technical Reports Server (NTRS)

    Lenda, J. A.

    1978-01-01

    The space shuttle will provide an opportunity to extend and enhance the crew's inherent capabilities in orbit by allowing them to operate effectively outside of their spacecraft by means of extravehicular activity. For this role, the shuttle crew will have a new, easier to don and operate space suit with integral life support system, and a self-contained propulsive backpack. The backpack, called the manned maneuvering unit, will allow the crew to operate beyond the confines of the Shuttle cargo bay and fly to any part of their own spacecraft or to nearby free-flying payloads or structure. This independent mobility will be used to support a wide variety of activities including free-space transfer of cargo and personnel, inspection and monitoring of orbital operations, and construction and assembly of large structures in orbit.

  3. Orbital Maneuvering system design evolution

    NASA Technical Reports Server (NTRS)

    Gibson, C.; Humphries, C.

    1985-01-01

    Preliminary design considerations and changes made in the baseline space shuttle orbital maneuvering system (OMS) to reduce cost and weight are detailed. The definition of initial subsystem requirements, trade studies, and design approaches are considered. Design features of the engine, its injector, combustion chamber, nozzle extension and bipropellant valve are illustrated and discussed. The current OMS consists of two identical pods that use nitrogen tetroxide (NTO) and monomethylhydrazine (MMH) propellants to provide 1000 ft/sec of delta velocity for a payload of 65,000 pounds. Major systems are pressurant gas storage and control, propellant storage supply and quantity measurement, and the rocket engine, which includes a bipropellant valve, an injector/thrust chamber, and a nozzle. The subsystem provides orbit insertion, circularization, and on orbit and deorbit capability for the shuttle orbiter.

  4. The Effect of Increased Temperatures and Ultraviolet Radiation on Dissolved Oxygen in Ecosystems Primarily Comprised of "Euglena"

    ERIC Educational Resources Information Center

    Carpenter, Matt

    2009-01-01

    The purpose of this study was to determine whether increased levels of UV radiation and temperatures from global warming have a significant impact on dissolved oxygen (DO) output from the alga, "Euglena," which affects other organisms in the ecosystem. The original hypothesis stated that if temperature was increased along with exposure time to…

  5. Multi-Maneuver Clohessy-Wiltshire Targeting

    NASA Technical Reports Server (NTRS)

    Dannemiller, David P.

    2011-01-01

    Orbital rendezvous involves execution of a sequence of maneuvers by a chaser vehicle to bring the chaser to a desired state relative to a target vehicle while meeting intermediate and final relative constraints. Intermediate and final relative constraints are necessary to meet a multitude of requirements such as to control approach direction, ensure relative position is adequate for operation of space-to-space communication systems and relative sensors, provide fail-safe trajectory features, and provide contingency hold points. The effect of maneuvers on constraints is often coupled, so the maneuvers must be solved for as a set. For example, maneuvers that affect orbital energy change both the chaser's height and downrange position relative to the target vehicle. Rendezvous designers use experience and rules-of-thumb to design a sequence of maneuvers and constraints. A non-iterative method is presented for targeting a rendezvous scenario that includes a sequence of maneuvers and relative constraints. This method is referred to as Multi-Maneuver Clohessy-Wiltshire Targeting (MM_CW_TGT). When a single maneuver is targeted to a single relative position, the classic CW targeting solution is obtained. The MM_CW_TGT method involves manipulation of the CW state transition matrix to form a linear system. As a starting point for forming the algorithm, the effects of a series of impulsive maneuvers on the state are derived. Simple and moderately complex examples are used to demonstrate the pattern of the resulting linear system. The general form of the pattern results in an algorithm for formation of the linear system. The resulting linear system relates the effect of maneuver components and initial conditions on relative constraints specified by the rendezvous designer. Solution of the linear system includes the straight-forward inverse of a square matrix. Inversion of the square matrix is assured if the designer poses a controllable scenario - a scenario where the the

  6. Manipulation of oxygenation and flow-induced shear stress can increase the in vitro yield of platelets from cord blood.

    PubMed

    Lasky, Larry C; Sullenbarger, Brent

    2011-11-01

    A method to produce clinically useful platelets in vitro would help overcome the frequent shortages, donor deferrals, disease transmission, and alloimmunization with volunteer donor-derived platelets. Using CD34 positively selected cord blood cells, we investigated ways to increase platelet quality and yield in a three-dimensional modular perfusion bioreactor system. We found a two- to threefold increase in platelet numbers produced only when the early phases of the culture process were carried out at 5% oxygen, versus when 20% oxygen was used throughout the culture period (p<0.05), and much more than when 5% oxygen was used throughout. When the medium was routed through the cell-scaffold construct, versus when it flowed under and over the construct, or just intermittent feeding was used, the number of platelets increased two- to threefold (p<0.05), and enhanced collagen-induced aggregation. The 5% oxygen early in the culture process mimics the marrow adjacent to the bone where early progenitors proliferate. Flow through the cell-scaffold construct creates shear forces that mimic the flow in central venous sinuses of the marrow and enhances platelet production from proplatelets. The use of altered oxygen levels and cross flow enhanced platelet numbers and quality, and will contribute to eventual in vitro platelet production for clinical use.

  7. Cassini Solstice Mission Maneuver Experience: Year One

    NASA Technical Reports Server (NTRS)

    Wagner, Sean V.; Arrieta, Juan; Ballard, Christopher G.; Hahn, Yungsun; Stumpf, Paul W.; Valerino, Powtawche N.

    2011-01-01

    The Cassini-Huygens spacecraft began its four-year Prime Mission to study Saturn's system in July 2004. Two tour extensions followed: a two-year Equinox Mission beginning in July 2008 and a seven-year Solstice Mission starting in September 2010. This paper highlights Cassini maneuver activities from June 2010 through June 2011, covering the transition from the Equinox to Solstice Mission. This interval included 38 scheduled maneuvers, nine targeted Titan flybys, three targeted Enceladus flybys, and one close Rhea flyby. In addition, beyond the demanding nominal navigation schedule, numerous unforeseen challenges further complicated maneuver operations. These challenges will be discussed in detail.

  8. [Reactive oxygen species are triggers and mediators of an increase in cardiac tolerance to impact of ischemia-reperfusion].

    PubMed

    Maslov, L N; Naryzhnaia, N V; Podoksenov, Iu K; Prokudina, E S; Gorbunov, A S; Zhang, I; Peĭ, Zh-M

    2015-01-01

    Reactive oxygen species (ROS) are triggers of ischemic preconditioning (IP). On the role of intracellular messengers of such cardioprotective effect of preconditioning claim: O2*, H2O2, OH*. However, we cannot exclude the possibility that other reactive oxygen metabolites also involved in the IP. Presented data suggest that IP enhances the production of ROS. The source of ROS may be mitochondrial respiratory chain and NADPH oxidase. Exogenous reactive oxygen species (O2*, H2O2) mimic the cardioprotective effect of preconditioning. Preconditioning prevents free radical damage of the heart during ischemia-reperfusion. The protective effect of IP is the consequence of reducing the production of ROS or the result of increased formation of endogenous antioxidants. Antioxidant enzymes are not involved in the protective effect of IP. Cardioprotective effect of many compounds (bradykinin, opioids, acetylcholine, phenylephrine, tumor necrosis factor-α, volatile anesthetics, protonophores, diazoxide, angiotensin II) depends on the increased production of ROS. PMID:25868322

  9. Infusion of ATP increases leg oxygen delivery but not oxygen uptake in the initial phase of intense knee-extensor exercise in humans.

    PubMed

    Nyberg, Michael; Christensen, Peter M; Mortensen, Stefan P; Hellsten, Ylva; Bangsbo, Jens

    2014-10-01

    The present study examined whether an increase in leg blood flow and oxygen delivery at the onset of intense exercise would speed the rate of rise in leg oxygen uptake. Nine healthy men (25 ± 1 years old, mean ± SEM) performed one-leg knee-extensor exercise (62 ± 3 W, 86 ± 3% of incremental test peak power) for 4 min during a control setting (CON) and with infusion of ATP into the femoral artery in order to increase blood flow before and during exercise. In the presence of ATP, femoral arterial blood flow and O2 delivery were higher (P < 0.001) at the onset of exercise and throughout exercise (femoral arterial blood flow after 10 s, 5.1 ± 0.5 versus 2.7 ± 0.3 l min(-1); after 45 s, 6.0 ± 0.5 versus 4.1 ± 0.4 l min(-1); after 90 s, 6.6 ± 0.6 versus 4.5 ± 0.4 l min(-1); and after 240 s, 7.0 ± 0.6 versus 5.1 ± 0.3 l min(-1) in ATP and CON conditions, respectively). Leg oxygen uptake was not different in ATP and CON conditions during the first 20 s of exercise but was lower (P < 0.05) in the ATP compared with CON conditions after 30 s and until the end of exercise (30 s, 436 ± 42 versus 549 ± 45 ml min(-1); and 240 s, 705 ± 31 versus 814 ± 59 ml min(-1) in ATP and CON, respectively). Lactate release was lower after 60, 120 and 180 s of exercise with ATP infusion. These results suggest that O2 delivery is not limiting the rise in skeletal muscle oxygen uptake in the initial phase of intense exercise. PMID:25085840

  10. X-31 in flight - Mongoose Maneuver

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Two X-31 Enhanced Fighter Maneuverability (EFM) demonstrators were flown at the Rockwell International facility, Palmdale, California, and the NASA Dryden Flight Research Center, Edwards, California, to obtain data that may apply to the design of highly-maneuverable next-generation fighters. The program had its first flight on October 11, 1990, in Palmdale; it ended in June 1995. The X-31 program demonstrated the value of thrust vectoring (directing engine exhaust flow) coupled with advanced flight control systems, to provide controlled flight during close-in air combat at very high angles of attack. The result of this increased maneuverability is an aircraft with a significant advantage over conventional fighters. 'Angle-of-attack' (alpha) is an engineering term to describe the angle of an aircraft body and wings relative to its actual flight path. During maneuvers, pilots often fly at extreme angles of attack -- with the nose pitched up while the aircraft continues in its original direction. This can lead to loss of control and result in the loss of the aircraft, pilot or both. Three thrust-vectoring paddles made of graphite epoxy mounted on the exhaust nozzle of the X-31 aircraft directed the exhaust flow to provide control in pitch (up and down) and yaw (right and left) to improve control. The paddles can sustain heat of up to 1,500 degrees centigrade for extended periods of time. In addition the X-31 aircraft were configured with movable forward canards and fixed aft strakes. The canards were small wing-like structures set on the wing line between the nose and the leading edge of the wing. The strakes were set on the same line between the trailing edge of the wing and the engine exhaust. Both supplied additional control in tight maneuvering situations. The X-31 research program produced technical data at high angles of attack. This information is giving engineers and aircraft designers a better understanding of aerodynamics, effectiveness of flight controls

  11. Intrathoracic pressure changes after Valsalva strain and other maneuvers: implications for divers with patent foramen ovale.

    PubMed

    Balestra, C; Germonpré, P; Marroni, A

    1998-01-01

    Scuba divers with patent foramen ovale (PFO) may be at risk for paradoxical nitrogen gas emboli when performing maneuvers that cause a rebound blood loading to the right atrium. We measured the rise and fall in intrathoracic pressure (ITP) during various maneuvers in 15 divers. The tests were standard isometric exercises (control), forceful coughing, knee bend (with and without respiration blocked), and Valsalva maneuver (maximal, gradually increased to reach control ITP, and as performed by divers to equalize middle ear pressure). All the maneuvers, as well as the downward slope of ITP at the release phase, were related to the control value. ITP levels were significantly higher than the standard isometric effort during a breath-hold knee bend (172%, P < 0.001), cough (133%, P < 0.05), and maximal Valsalva (136%, P < 0.05) whereas "usual" Valsalva maneuvers produced ITPs significantly lower than the standard (28%, P < 0.001). The downward slope of the pressure release curve was not significantly different among the different maneuvers (P < 0.1447). We conclude that maneuvers other than the usual divers' Valsalva are more likely to cause post-release central blood shift, both by the levels of ITP reached and by the time during which these ITPs are sustained. Divers (especially with PFO) should be advised to refrain from strenuous leg, arm, or abdominal exercise after decompression dives.

  12. 3D modeling of effects of increased oxygenation and activity concentration in tumors treated with radionuclides and antiangiogenic drugs

    SciTech Connect

    Lagerloef, Jakob H.; Kindblom, Jon; Bernhardt, Peter

    2011-08-15

    Purpose: Formation of new blood vessels (angiogenesis) in response to hypoxia is a fundamental event in the process of tumor growth and metastatic dissemination. However, abnormalities in tumor neovasculature often induce increased interstitial pressure (IP) and further reduce oxygenation (pO{sub 2}) of tumor cells. In radiotherapy, well-oxygenated tumors favor treatment. Antiangiogenic drugs may lower IP in the tumor, improving perfusion, pO{sub 2} and drug uptake, by reducing the number of malfunctioning vessels in the tissue. This study aims to create a model for quantifying the effects of altered pO{sub 2}-distribution due to antiangiogenic treatment in combination with radionuclide therapy. Methods: Based on experimental data, describing the effects of antiangiogenic agents on oxygenation of GlioblastomaMultiforme (GBM), a single cell based 3D model, including 10{sup 10} tumor cells, was developed, showing how radionuclide therapy response improves as tumor oxygenation approaches normal tissue levels. The nuclides studied were {sup 90}Y, {sup 131}I, {sup 177}Lu, and {sup 211}At. The absorbed dose levels required for a tumor control probability (TCP) of 0.990 are compared for three different log-normal pO{sub 2}-distributions: {mu}{sub 1} = 2.483, {sigma}{sub 1} = 0.711; {mu}{sub 2} = 2.946, {sigma}{sub 2} = 0.689; {mu}{sub 3} = 3.689, and {sigma}{sub 3} = 0.330. The normal tissue absorbed doses will, in turn, depend on this. These distributions were chosen to represent the expected oxygen levels in an untreated hypoxic tumor, a hypoxic tumor treated with an anti-VEGF agent, and in normal, fully-oxygenated tissue, respectively. The former two are fitted to experimental data. The geometric oxygen distributions are simulated using two different patterns: one Monte Carlo based and one radially increasing, while keeping the log-normal volumetric distributions intact. Oxygen and activity are distributed, according to the same pattern. Results: As tumor pO{sub 2

  13. Acute Supramaximal Exercise Increases the Brain Oxygenation in Relation to Cognitive Workload

    PubMed Central

    Bediz, Cem Seref; Oniz, Adile; Guducu, Cagdas; Ural Demirci, Enise; Ogut, Hilmi; Gunay, Erkan; Cetinkaya, Caner; Ozgoren, Murat

    2016-01-01

    Single bout of exercise can improve the performance on cognitive tasks. However, cognitive responses may be controversial due to different type, intensity, and duration of exercise. In addition, the mechanism of the effect of acute exercise on brain is still unclear. This study was aimed to investigate the effects of supramaximal exercise on cognitive tasks by means of brain oxygenation monitoring. The brain oxygenation of Prefrontal cortex (PFC) was measured on 35 healthy male volunteers via functional near infrared spectroscopy (fNIRS) system. Subjects performed 2-Back test before and after the supramaximal exercise wingate anerobic test (WAnT) lasting 30-s on cycle ergometer. The PFC oxygenation change evaluation revealed that PFC oxygenation rise during post-exercise 2-Back task was considerably higher than those in pre-exercise 2-Back task. In order to describe the relationship between oxygenation change and exercise performance, subjects were divided into two groups as high performers (HP) and low performers (LP) according to their peak power values (PP) obtained from the supramaximal test. The oxy-hemoglobin (oxy-Hb) values were compared between pre- and post-exercise conditions within subjects and also between subjects according to peak power. When performers were compared, in the HP group, the oxy-Hb values in post-exercise 2-Back test were significantly higher than those in pre-exercise 2-Back test. HP had significantly higher post-exercise oxy-Hb change (Δ) than those of LP. In addition, PP of the total group were significantly correlated with Δoxy-Hb.The key findings of the present study revealed that acute supramaximal exercise has an impact on the brain oxygenation during a cognitive task. Also, the higher the anerobic PP describes the larger the oxy-Hb response in post-exercise cognitive task. The current study also demonstrated a significant correlation between peak power (exercise load) and post-exercise hemodynamic responses (oxy-, deoxy- and

  14. Acute Supramaximal Exercise Increases the Brain Oxygenation in Relation to Cognitive Workload.

    PubMed

    Bediz, Cem Seref; Oniz, Adile; Guducu, Cagdas; Ural Demirci, Enise; Ogut, Hilmi; Gunay, Erkan; Cetinkaya, Caner; Ozgoren, Murat

    2016-01-01

    Single bout of exercise can improve the performance on cognitive tasks. However, cognitive responses may be controversial due to different type, intensity, and duration of exercise. In addition, the mechanism of the effect of acute exercise on brain is still unclear. This study was aimed to investigate the effects of supramaximal exercise on cognitive tasks by means of brain oxygenation monitoring. The brain oxygenation of Prefrontal cortex (PFC) was measured on 35 healthy male volunteers via functional near infrared spectroscopy (fNIRS) system. Subjects performed 2-Back test before and after the supramaximal exercise wingate anerobic test (WAnT) lasting 30-s on cycle ergometer. The PFC oxygenation change evaluation revealed that PFC oxygenation rise during post-exercise 2-Back task was considerably higher than those in pre-exercise 2-Back task. In order to describe the relationship between oxygenation change and exercise performance, subjects were divided into two groups as high performers (HP) and low performers (LP) according to their peak power values (PP) obtained from the supramaximal test. The oxy-hemoglobin (oxy-Hb) values were compared between pre- and post-exercise conditions within subjects and also between subjects according to peak power. When performers were compared, in the HP group, the oxy-Hb values in post-exercise 2-Back test were significantly higher than those in pre-exercise 2-Back test. HP had significantly higher post-exercise oxy-Hb change (Δ) than those of LP. In addition, PP of the total group were significantly correlated with Δoxy-Hb.The key findings of the present study revealed that acute supramaximal exercise has an impact on the brain oxygenation during a cognitive task. Also, the higher the anerobic PP describes the larger the oxy-Hb response in post-exercise cognitive task. The current study also demonstrated a significant correlation between peak power (exercise load) and post-exercise hemodynamic responses (oxy-, deoxy- and

  15. 14 CFR 23.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit maneuvering load factors. 23.337... Flight Loads § 23.337 Limit maneuvering load factors. (a) The positive limit maneuvering load factor n... airplanes; or (3) 6.0 for acrobatic category airplanes. (b) The negative limit maneuvering load factor...

  16. 14 CFR 29.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit maneuvering load factor. 29.337... Limit maneuvering load factor. The rotorcraft must be designed for— (a) A limit maneuvering load factor... load factor not less than 2.0 and any negative limit maneuvering load factor of not less than −0.5...

  17. 14 CFR 27.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit maneuvering load factor. 27.337... Limit maneuvering load factor. The rotorcraft must be designed for— (a) A limit maneuvering load factor... load factor not less than 2.0 and any negative limit maneuvering load factor of not less than −0.5...

  18. A Fuel-Efficient Conflict Resolution Maneuver for Separation Assurance

    NASA Technical Reports Server (NTRS)

    Bowe, Aisha Ruth; Santiago, Confesor

    2012-01-01

    Automated separation assurance algorithms are envisioned to play an integral role in accommodating the forecasted increase in demand of the National Airspace System. Developing a robust, reliable, air traffic management system involves safely increasing efficiency and throughput while considering the potential impact on users. This experiment seeks to evaluate the benefit of augmenting a conflict detection and resolution algorithm to consider a fuel efficient, Zero-Delay Direct-To maneuver, when resolving a given conflict based on either minimum fuel burn or minimum delay. A total of twelve conditions were tested in a fast-time simulation conducted in three airspace regions with mixed aircraft types and light weather. Results show that inclusion of this maneuver has no appreciable effect on the ability of the algorithm to safely detect and resolve conflicts. The results further suggest that enabling the Zero-Delay Direct-To maneuver significantly increases the cumulative fuel burn savings when choosing resolution based on minimum fuel burn while marginally increasing the average delay per resolution.

  19. Decreased Endothelial Nitric Oxide Bioavailability, Impaired Microvascular Function, and Increased Tissue Oxygen Consumption in Children with Falciparum Malaria

    PubMed Central

    Yeo, Tsin W.; Lampah, Daniel A.; Kenangalem, Enny; Tjitra, Emiliana; Weinberg, J. Brice; Granger, Donald L.; Price, Ric N.; Anstey, Nicholas M.

    2014-01-01

    Endothelial nitric oxide (NO) bioavailability, microvascular function, and host oxygen consumption have not been assessed in pediatric malaria. We measured NO-dependent endothelial function by using peripheral artery tonometry to determine the reactive hyperemia index (RHI), and microvascular function and oxygen consumption (VO2) using near infrared resonance spectroscopy in 13 Indonesian children with severe falciparum malaria and 15 with moderately severe falciparum malaria. Compared with 19 controls, children with severe malaria and those with moderately severe malaria had lower RHIs (P = .03); 12% and 8% lower microvascular function, respectively (P = .03); and 29% and 25% higher VO2, respectively. RHIs correlated with microvascular function in all children with malaria (P < .001) and all with severe malaria (P < .001). Children with malaria have decreased endothelial and microvascular function and increased oxygen consumption, likely contributing to the pathogenesis of the disease. PMID:24879801

  20. Decreased endothelial nitric oxide bioavailability, impaired microvascular function, and increased tissue oxygen consumption in children with falciparum malaria.

    PubMed

    Yeo, Tsin W; Lampah, Daniel A; Kenangalem, Enny; Tjitra, Emiliana; Weinberg, J Brice; Granger, Donald L; Price, Ric N; Anstey, Nicholas M

    2014-11-15

    Endothelial nitric oxide (NO) bioavailability, microvascular function, and host oxygen consumption have not been assessed in pediatric malaria. We measured NO-dependent endothelial function by using peripheral artery tonometry to determine the reactive hyperemia index (RHI), and microvascular function and oxygen consumption (VO2) using near infrared resonance spectroscopy in 13 Indonesian children with severe falciparum malaria and 15 with moderately severe falciparum malaria. Compared with 19 controls, children with severe malaria and those with moderately severe malaria had lower RHIs (P = .03); 12% and 8% lower microvascular function, respectively (P = .03); and 29% and 25% higher VO2, respectively. RHIs correlated with microvascular function in all children with malaria (P < .001) and all with severe malaria (P < .001). Children with malaria have decreased endothelial and microvascular function and increased oxygen consumption, likely contributing to the pathogenesis of the disease.

  1. The acute antinociceptive effect of hyperbaric oxygen is not accompanied by an increase in markers of oxidative stress

    PubMed Central

    Liu, Shulin; Shirachi, Donald Y.; Quock, Raymond M.

    2014-01-01

    Aims Exposure to hyperbaric oxygen (HBO2) causes an antinociceptive response in mice. However, breathing oxygen (O2) at an elevated pressure can potentially cause oxygen toxicity. The aim of this study was to identify the determinants of HBO2 antinociception and the toxicity profile of HBO2. Main methods Male NIH Swiss mice were assessed for acute antinociceptive responsiveness under room air or 100% O2 at 1.0 or 3.5 atmospheres absolute (ATA), using the acetic acid-induced abdominal constriction test. For the oxygen toxicity test, mice were exposed to 3.5 ATA oxygen for 11 min, 60 min, 60 min daily for 2 days (120 min) or 60 min daily for 4 days (240 min), then assessed by analyzing the levels of two oxidative stress markers, MDA (malondialdehyde) and protein carbonyl in brain, spinal cord and lung. Key Findings Only the combination of 100% O2 and 3.5 ATA caused significant antinociception. The antinociceptive effect of 100% O2 was pressure-dependent up to 3.5 ATA. In the oxygen toxicity test, mice exposed to HBO2 for different time intervals had levels of brain, spinal cord and lung MDA and protein carbonyl that were comparable to that of control animals exposed to room air. Significance Treatment with 100% O2 evokes a pressure-dependent antinociceptive effect. Since there was no significant increase in levels of the oxidative stress markers in the tested tissues, it is concluded HBO2 at 3.5 ATA produces antinociception in the absence of oxidative stress in mice. PMID:24418003

  2. NOTE: Increasing cardiac output and decreasing oxygenation sequence in pump twins of acardiac twin pregnancies

    NASA Astrophysics Data System (ADS)

    van Gemert, Martin J. C.; Umur, Asli; van den Wijngaard, Jeroen P. H. M.; Van Bavel, Ed; Vandenbussche, Frank P. H. A.; Nikkels, Peter G. J.

    2005-02-01

    An acardiac twin pregnancy is a rare but serious complication of monochorionic twinning and consists of an acardiac twin and a pump twin. The acardiac twin is a severely malformed fetus that lacks most organs, particularly a heart, but grows during pregnancy because it is perfused by the developmentally normal pump twin via a set of arterioarterial and venovenous placental anastomoses. Pump twins die intrauterine or neonatally in about 50% of the cases. Because the effects of an acardiac mass on the pump twin's development are incompletely known, methods for outcome prognosis are currently not available. We sought to derive simple relations for the pump twin's excess cardiac output and decreased oxygenation and to use available clinical cases for a preliminary test of the model. As a method, we used a theoretical flow model to represent the fetoplacental circulation of an acardiac twin pregnancy and estimated blood deoxygenation and reoxygenation following perfusion of the two bodies and placentas, respectively. The results show the pump twin's excess cardiac output and decrease of venous oxygen saturation to depend on the ratio of pump twin to acardiac twin umbilical blood flow, whose ratio can be measured by ultrasonography. The clinical cases show a decreasing umbilical flow ratio with gestation. In conclusion, prospective serial study is necessary to test whether measurement of umbilical flow ratios allows monitoring the pump twin's pathophysiologic development, possibly resulting in a guideline for prognosis of pump twin survival.

  3. A Computer Simulation of the System-Wide Effects of Parallel-Offset Route Maneuvers

    NASA Technical Reports Server (NTRS)

    Lauderdale, Todd A.; Santiago, Confesor; Pankok, Carl

    2010-01-01

    Most aircraft managed by air-traffic controllers in the National Airspace System are capable of flying parallel-offset routes. This paper presents the results of two related studies on the effects of increased use of offset routes as a conflict resolution maneuver. The first study analyzes offset routes in the context of all standard resolution types which air-traffic controllers currently use. This study shows that by utilizing parallel-offset route maneuvers, significant system-wide savings in delay due to conflict resolution of up to 30% are possible. It also shows that most offset resolutions replace horizontal-vectoring resolutions. The second study builds on the results of the first and directly compares offset resolutions and standard horizontal-vectoring maneuvers to determine that in-trail conflicts are often more efficiently resolved by offset maneuvers.

  4. Cassini's Maneuver Automation Software (MAS) Process: How to Successfully Command 200 Navigation Maneuvers

    NASA Technical Reports Server (NTRS)

    Yang, Genevie Velarde; Mohr, David; Kirby, Charles E.

    2008-01-01

    To keep Cassini on its complex trajectory, more than 200 orbit trim maneuvers (OTMs) have been planned from July 2004 to July 2010. With only a few days between many of these OTMs, the operations process of planning and executing the necessary commands had to be automated. The resulting Maneuver Automation Software (MAS) process minimizes the workforce required for, and maximizes the efficiency of, the maneuver design and uplink activities. The MAS process is a well-organized and logically constructed interface between Cassini's Navigation (NAV), Spacecraft Operations (SCO), and Ground Software teams. Upon delivery of an orbit determination (OD) from NAV, the MAS process can generate a maneuver design and all related uplink and verification products within 30 minutes. To date, all 112 OTMs executed by the Cassini spacecraft have been successful. MAS was even used to successfully design and execute a maneuver while the spacecraft was in safe mode.

  5. Increased Stability Toward Oxygen Reduction Products for Lithium-Air Batteries with Oligoether-Functionalized Silane Electrolytes

    SciTech Connect

    Zhang, Zhengcheng; Lu, Jun; Assary, Rajeev S.; Du, Peng; Wang, Hsien-Hau; Sun, Yang-Kook; Qin, Yan; Lau, Kah Chun; Greeley, Jeffrey P.; Redfern, Paul C.; Iddir, Hakim; Curtiss, Larry A.; Amine, Khalil

    2011-12-29

    The successful development of Li-air batteries would significantly increase the possibility of extending the range of electric vehicles. There is much evidence that typical organic carbonate based electrolytes used in lithium ion batteries form lithium carbonates from reaction with oxygen reduction products during discharge in lithium-air cells so more stable electrolytes need to be found. This combined experimental and computational study of an electrolyte based on a tri(ethylene glycol)-substituted trimethylsilane (1NM3) provides evidence that the ethers are more stable toward oxygen reduction discharge species. X-ray photoelectron spectroscopy (XPS) and FTIR experiments show that only lithium oxides and no carbonates are formed when 1NM3 electrolyte is used. In contrast XPS shows that propylene carbonate (PC) in the same cell configuration decomposes to form lithium carbonates during discharge. Density functional calculations of probable decomposition reaction pathways involving solvated oxygen reduction species confirm that oligoether substituted silanes, as well as other ethers, are more stable to the oxygen reduction products than propylene carbonate. These results indicate that the choice of electrolyte plays a key role in the performance of Li-air batteries.

  6. Dramatic increase in the oxygen reduction reaction for platinum cathodes from tuning the solvent dielectric constant.

    PubMed

    Fortunelli, Alessandro; Goddard, William A; Sha, Yao; Yu, Ted H; Sementa, Luca; Barcaro, Giovanni; Andreussi, Oliviero

    2014-06-23

    Hydrogen fuel cells (FC) are considered essential for a sustainable economy based on carbon-free energy sources, but a major impediment are the costs. First-principles quantum mechanics (density functional theory including solvation) is used to predict how the energies and barriers for the mechanistic steps of the oxygen reduction reaction (ORR) over the fcc(111) platinum surface depend on the dielectric constant of the solvent. The ORR kinetics can be strongly accelerated by decreasing the effective medium polarizability from the high value it has in water. Possible ways to realize this experimentally are suggested. The calculated volcano structure for the dependence of rate on solvent polarization is considered to be general, and should be observed in other electrochemical systems.

  7. Increased oxygen load in the prefrontal cortex from mouth breathing: a vector-based near-infrared spectroscopy study.

    PubMed

    Sano, Masahiro; Sano, Sayaka; Oka, Noriyuki; Yoshino, Kayoko; Kato, Toshinori

    2013-12-01

    Individuals who habitually breathe through the mouth are more likely than nasal breathers to have sleep disorders and attention deficit hyperactive disorder. We hypothesized that brain hemodynamic responses in the prefrontal cortex might be different for mouth and nasal breathing. To test this hypothesis, we measured changes in oxyhemoglobin and deoxyhemoglobin in the prefrontal cortex during mouth breathing and nasal breathing in healthy adults (n=9) using vector-based near-infrared spectroscopy. The angle k, calculated from changes in oxyhemoglobin and deoxyhemoglobin and indicating the degree of oxygen exchange, was significantly higher during mouth breathing (P<0.05), indicating an increased oxygen load. Mouth breathing also caused a significant increase in deoxyhemoglobin, but oxyhemoglobin did not increase. This difference in oxygen load in the brain arising from different breathing routes can be evaluated quantitatively using vector-based near-infrared spectroscopy. Phase responses could help to provide an earlier and more reliable diagnosis of a patient's habitual breathing route than a patient interview.

  8. Partitioning kinetic energy during freewheeling wheelchair maneuvers.

    PubMed

    Medola, Fausto O; Dao, Phuc V; Caspall, Jayme J; Sprigle, Stephen

    2014-03-01

    This paper describes a systematic method to partition the kinetic energy (KE) of a free-wheeling wheelchair. An ultralightweight rigid frame wheelchair was instrumented with two axle-mounted encoders and data acquisition equipment to accurately measure the velocity of the drive wheels. A mathematical model was created combining physical specifications and geometry of the wheelchair and its components. Two able-bodied subjects propelled the wheelchair over four courses that involved straight and turning maneuvers at differing speeds. The KE of the wheelchair was divided into three components: translational, rotational, and turning energy. This technique was sensitive to the changing contributions of the three energy components across maneuvers. Translational energy represented the major component of total KE in all maneuvers except a zero radius turn in which turning energy was dominant. Both translational and rotational energies are directly related to wheelchair speed. Partitioning KE offers a useful means of investigating the dynamics of a moving wheelchair. The described technique permits analysis of KE imparted to the wheelchair during maneuvers involving changes in speed and direction, which are most representative of mobility in everyday life. This technique can be used to study the effort required to maneuver different types and configurations of wheelchairs.

  9. Recruitment maneuvers in acute respiratory distress syndrome: The safe way is the best way.

    PubMed

    Santos, Raquel S; Silva, Pedro L; Pelosi, Paolo; Rocco, Patricia Rm

    2015-11-01

    Acute respiratory distress syndrome (ARDS) represents a serious problem in critically ill patients and is associated with in-hospital mortality rates of 33%-52%. Recruitment maneuvers (RMs) are a simple, low-cost, feasible intervention that can be performed at the bedside in patients with ARDS. RMs are characterized by the application of airway pressure to increase transpulmonary pressure transiently. Once non-aerated lung units are reopened, improvements are observed in respiratory system mechanics, alveolar reaeration on computed tomography, and improvements in gas exchange (functional recruitment). However, the reopening process could lead to vascular compression, which can be associated with overinflation, and gas exchange may not improve as expected (anatomical recruitment). The purpose of this review was to discuss the effects of different RM strategies - sustained inflation, intermittent sighs, and stepwise increases of positive end-expiratory pressure (PEEP) and/or airway inspiratory pressure - on the following parameters: hemodynamics, oxygenation, barotrauma episodes, and lung recruitability through physiological variables and imaging techniques. RMs and PEEP titration are interdependent events for the success of ventilatory management. PEEP should be adjusted on the basis of respiratory system mechanics and oxygenation. Recent systematic reviews and meta-analyses suggest that RMs are associated with lower mortality in patients with ARDS. However, the optimal RM method (i.e., that providing the best balance of benefit and harm) and the effects of RMs on clinical outcome are still under discussion, and further evidence is needed.

  10. Maneuver Performance Enhancement for an Advanced Fighter/Attack Aircraft

    NASA Technical Reports Server (NTRS)

    Samuels, Jeff; Langan, Kevin J.; Schmitz, Frederic H. (Technical Monitor)

    1994-01-01

    A small scale wind tunnel test of a realistic fighter configuration has been completed in NASA Ames' 7'x10' wind tunnel. This test was part of the Fighter Lift and Control (FLAC) program, a joint NASA - USAF research program, involving small and large-scale wind-tunnel tests and computational analysis of unique lift augmentation and control devices. The goal of this program is to enhance the maneuver and control capability of next-generation Air Force multi-role fighter aircraft with low-observables geometries. The principal objective of this test was to determine the effectiveness of passive boundary layer control devices at increasing L/D at sustained maneuver lift coefficients. Vortex generators (VGs) were used to energize the boundary layer to prevent or delay separation. Corotating vanes, counter-rotating vanes, and Wheeler Wishbone VGs were used in the vicinity of the leading and trailing edge flap hinge lines. Principle test parameters were leading and trailing edge flap deflections, and location, size, spacing, and orientation for each VG type. Gurney flaps were also tested. Data gathered include balance force and moment data, surface pressures, and flow visualization for characterizing flow behavior and locating separation lines. Results were quite different for the two best flap configurations tested. All VG types tested showed improvement (up to 5%) in maneuver L/D with flaps at LE=20 degrees, TE=0 degrees. The same VGs degraded performance, in all but a few cases, with flaps at LE=15 degrees, TE=10 degrees.

  11. Dawn Statistical Maneuver Design for Vesta Operations

    NASA Technical Reports Server (NTRS)

    Parcher, Daniel W.; Whiffen, Gregory J.

    2011-01-01

    In July of 2011 the Dawn spacecraft is scheduled to begin orbital operations at Vesta, a large main-belt asteroid. Dawn is a NASA Discovery mission that uses solar-electric low-thrust ion propulsion for both interplanetary cruise and orbital operations. Navigating between the Dawn project's four targeted science orbits at Vesta requires a plan that accounts for uncertainties not only in thrust execution, orbit determination, and other spacecraft forces, but also large uncertainties in characteristics of Vesta - such as the asteroid's gravity field and pole orientation. Accommodating these uncertainties requires strategic use of low-thrust maneuvers reserved for statistical trajectory corrections. This paper describes the placement and evaluation of low-thrust statistical maneuvers during two key phases of the Vesta mission along with a discussion of the tools, constraints, and methods used to plan those maneuvers.

  12. Cassini Maneuver Experience: Ending the Equinox Mission

    NASA Technical Reports Server (NTRS)

    Ballard, Christopher G.; Arrieta, Juan; Hahn, Yungsun; Stumpf, Paul W.; Wagner, Sean V.; Williams, Powtawche N.

    2010-01-01

    The Cassini-Huygens spacecraft was launched in 1997 on a mission to observe Saturn and its many moons. After a seven-year interplanetary cruise, it entered a Saturnian orbit for a four-year Prime Mission in 2004 and began a two-year Equinox Mission in 2008. It has been approved for another seven-year mission, the Solstice Mission, starting in October 2010. This paper highlights significant maneuver activities performed from July 2009 to June 2010. We present results for the 45 maneuvers during this time. The successful navigation of the Cassini orbiter can be attributed in part to the accurate maneuver performance, which has greatly exceeded pre-launch expectations.

  13. An algorithm for targeting finite burn maneuvers

    NASA Technical Reports Server (NTRS)

    Barbieri, R. W.; Wyatt, G. H.

    1972-01-01

    An algorithm was developed to solve the following problem: given the characteristics of the engine to be used to make a finite burn maneuver and given the desired orbit, when must the engine be ignited and what must be the orientation of the thrust vector so as to obtain the desired orbit? The desired orbit is characterized by classical elements and functions of these elements whereas the control parameters are characterized by the time to initiate the maneuver and three direction cosines which locate the thrust vector. The algorithm was built with a Monte Carlo capability whereby samples are taken from the distribution of errors associated with the estimate of the state and from the distribution of errors associated with the engine to be used to make the maneuver.

  14. Maneuver and buffet characteristics of fighter aircraft

    NASA Technical Reports Server (NTRS)

    Ray, E. J.; Mckinney, L. W.; Carmichael, J. G.

    1973-01-01

    Recent research efforts in the improvement of the maneuverability of fighter aircraft in the high-subsonic and transonic speed range are reviewed with emphasis on the factors affecting aerodynamic boundaries, such as maximum obtainable lift, buffet onset, pitchup, wing rock, and nose slice. The investigations were made using a general research configuration which encompassed a systematic matrix of wing-design parameters. These results illustrated the sensitivity of section and planform geometry to a selected design point. The incorporation of variable-geometry wing devices in the form of flaps or leading-edge slats was shown to provide controlled flow over a wide range of flight conditions and substantial improvements in maneuver capabilities. Additional studies indicated that the blending of a highly swept maneuver strake with an efficient, moderately swept wing offers a promising approach for improving maneuver characteristics at high angles of attack without excessive penalties in structural weight.

  15. Maneuver and buffet characteristics of fighter aircraft

    NASA Technical Reports Server (NTRS)

    Ray, E. J.; Mckinney, L. W.; Carmichael, J. G.

    1972-01-01

    The high subsonic and transonic characteristics of fighter aircraft and the factors affecting aerodynamic boundaries, such as maximum obtainable lift, buffet onset, pitchup, wing rock, and nose slice are discussed. Investigations were made using a general research configuration which encompassed a systematic matrix of wing design parameters. These results emphasized the sensitivity to section and planform geometry at the selected design point. The incorporation of variable-wing-geometry devices in the form of leading-edge slats or flaps was shown in a number of flight and wind-tunnel studies to provide controlled flow over a wide range of flight conditions and substantial improvements in maneuver capabilities. Additional studies indicated that the blending of a highly swept maneuver strake with an efficient moderately swept wing offers a promising approach for improving maneuver characteristics at high angles of attack without excessive penalties in structural weight.

  16. Maneuvering and control of flexible space robots

    NASA Technical Reports Server (NTRS)

    Meirovitch, Leonard; Lim, Seungchul

    1994-01-01

    This paper is concerned with a flexible space robot capable of maneuvering payloads. The robot is assumed to consist of two hinge-connected flexible arms and a rigid end-effector holding a payload; the robot is mounted on a rigid platform floating in space. The equations of motion are nonlinear and of high order. Based on the assumption that the maneuvering motions are one order of magnitude larger than the elastic vibrations, a perturbation approach permits design of controls for the two types of motion separately. The rigid-body maneuvering is carried out open loop, but the elastic motions are controlled closed loop, by means of discrete-time linear quadratic regulator theory with prescribed degree of stability. A numerical example demonstrates the approach. In the example, the controls derived by the perturbation approach are applied to the original nonlinear system and errors are found to be relatively small.

  17. First demonstration of an increased serum level of reactive oxygen species during the peripartal period in the ewes.

    PubMed

    Rizzo, Annalisa; Mutinati, Maddalena; Spedicato, Massimo; Minoia, Giuseppe; Trisolini, Carmelinda; Jirillo, Felicita; Sciorsci, Raffaele Luigi

    2008-01-01

    Reactive Oxygen Species (ROS) are produced during oxidative metabolism, and regulate many biological processes. The acute inflammation characterizing parturition induces many physiological changes. Among them, there is evidence that ROS affect the synthesis of many factors involved in parturition. Our study aims to determine serum levels of ROS in periparturient ewes, as well as to establish a value of reference of their physiological concentration. ROS determination was performed on blood collected every 12 hours in periparturient twin pregnant ewes. Our results will show a significant increase in ROS concentrations from the beginning to the end of the experiment. This increase may be due to the inflammatory process establishing during parturition.

  18. Effect of width and boundary conditions on meeting maneuvers on two-way separated cycle tracks.

    PubMed

    Garcia, Alfredo; Gomez, Fernando Agustin; Llorca, Carlos; Angel-Domenech, Antonio

    2015-05-01

    Cycle track design guidelines are rarely based on scientific studies. In the case of off-road two-way cycle tracks, a minimum width must facilitate both passing and meeting maneuvers, being meeting maneuvers the most frequent. This study developed a methodology to observe meeting maneuvers using an instrumented bicycle, equipped with video cameras, a GPS tracker, laser rangefinders and speed sensors. This bicycle collected data on six two-way cycle tracks ranging 1.3-2.15m width delimitated by different boundary conditions. The meeting maneuvers between the instrumented bicycle and every oncoming bicycle were characterized by the meeting clearance between the two bicycles, the speed of opposing bicycle and the reaction of the opposing rider: change in trajectory, stop pedaling or braking. The results showed that meeting clearance increased with the cycle track width and decreased if the cycle track had lateral obstacles, especially if they were higher than the bicycle handlebar. The speed of opposing bicycle shown the same tendency, although were more disperse. Opposing cyclists performed more reaction maneuvers on narrower cycle tracks and on cycle tracks with lateral obstacles to the handlebar height. Conclusions suggested avoiding cycle tracks narrower than 1.6m, as they present lower meeting clearances, lower bicycle speeds and frequent reaction maneuvers. PMID:25779982

  19. Methane Post-Processor Development to Increase Oxygen Recovery beyond State-of-the-Art Carbon Dioxide Reduction Technology

    NASA Technical Reports Server (NTRS)

    Abney, Morgan; Miller, Lee; Greenwood, Zach; Iannantuono, Michelle; Jones, Kenny

    2013-01-01

    State-of-the-art life support carbon dioxide (CO2) reduction technology, based on the Sabatier reaction, is theoretically capable of 50% recovery of oxygen from metabolic CO2. This recovery is constrained by the limited availability of reactant hydrogen. Post-processing of the methane byproduct from the Sabatier reactor results in hydrogen recycle and a subsequent increase in oxygen recovery. For this purpose, a Methane Post-Processor Assembly containing three sub-systems has been developed and tested. The assembly includes a Methane Purification Assembly (MePA) to remove residual CO2 and water vapor from the Sabatier product stream, a Plasma Pyrolysis Assembly (PPA) to partially pyrolyze methane into hydrogen and acetylene, and an Acetylene Separation Assembly (ASepA) to purify the hydrogen product for recycle. The results of partially integrated testing of the sub-systems are reported.

  20. Advancing the Oxygen Generation Assembly Design to Increase Reliability and Reduce Costs for a Future Long Duration Mission

    NASA Technical Reports Server (NTRS)

    Takada, Kevin C.; Ghariani, Ahmed E.; Van Keuren,

    2015-01-01

    The state-of-the-art Oxygen Generation Assembly (OGA) has been reliably producing breathing oxygen for the crew aboard the International Space Station (ISS) for over eight years. Lessons learned from operating the ISS OGA have led to proposing incremental improvements to advance the baseline design for use in a future long duration mission. These improvements are intended to reduce system weight, crew maintenance time and resupply mass from Earth while increasing reliability. The proposed improvements include replacing the cell stack membrane material, deleting the nitrogen purge equipment, replacing the hydrogen sensors, deleting the wastewater interface, replacing the hydrogen dome and redesigning the cell stack power supply. The development work to date will be discussed and forward work will be outlined. Additionally, a redesigned system architecture will be proposed.

  1. Methane Post-Processor Development to Increase Oxygen Recovery beyond State-of-the-Art Carbon Dioxide Reduction Technology

    NASA Technical Reports Server (NTRS)

    Abney, Morgan B.; Greenwood, Zachary; Miller, Lee A.; Alvarez, Giraldo; Iannantuono, Michelle; Jones, Kenny

    2013-01-01

    State-of-the-art life support carbon dioxide (CO2) reduction technology, based on the Sabatier reaction, is theoretically capable of 50% recovery of oxygen from metabolic CO2. This recovery is constrained by the limited availability of reactant hydrogen. Post-processing of the methane byproduct from the Sabatier reactor results in hydrogen recycle and a subsequent increase in oxygen recovery. For this purpose, a Methane Post-Processor Assembly containing three sub-systems has been developed and tested. The assembly includes a Methane Purification Assembly (MePA) to remove residual CO2 and water vapor from the Sabatier product stream, a Plasma Pyrolysis Assembly (PPA) to partially pyrolyze methane into hydrogen and acetylene, and an Acetylene Separation Assembly (ASepA) to purify the hydrogen product for recycle. The results of partially integrated testing of the sub-systems are reported

  2. Cassini Solstice Mission Maneuver Experience: Year Two

    NASA Technical Reports Server (NTRS)

    Arrieta, Juan; Ballard, Christopher G.; Hahn, Yungsun

    2012-01-01

    The Cassini Spacecraft was launched in October 1997 on a mission to observe Saturn and its moons; it entered orbit around Saturn in July 2004 for a nominal four-year Prime Mission, later augmented by two extensions: the Equinox Mission, from July 2008 through September 2010, and the Solstice Mission, from October 2010 through September 2017. This paper provides an overview of the maneuver activities from August 2011 through June 2012 which include the design of 38 Orbit Trim Maneuvers--OTM-288 through OTM-326-- for attaining 14 natural satellite encounters: seven with Titan, six with Enceladus, and one with Dione.

  3. Mars Science Laboratory Cruise Propulsion Maneuvering Operations

    NASA Technical Reports Server (NTRS)

    Baker, Raymond S.; Mizukami, Masahi; Barber, Todd J.

    2013-01-01

    Mars Science Laboratory "Curiosity" is NASA's most recent mission to Mars, launched in November 2011, and landed in August 2012. It is a subcompact car-sized nuclear powered rover designed for a long duration mission, with an extensive suite of science instruments. Entry, descent and landing used a unique "skycrane" concept. This report describes the propulsive maneuvering operations during cruise from Earth to Mars, to control attitudes and to target the vehicle for entry. The propulsion subsystem, mission operations, and flight performance are discussed. All trajectory control maneuvers were well within accuracy requirements, and all turns and spin corrections were nominal.

  4. Surface recombination of oxygen atoms in O2 plasma at increased pressure: II. Vibrational temperature and surface production of ozone

    NASA Astrophysics Data System (ADS)

    Lopaev, D. V.; Malykhin, E. M.; Zyryanov, S. M.

    2011-01-01

    Ozone production in an oxygen glow discharge in a quartz tube was studied in the pressure range of 10-50 Torr. The O3 density distribution along the tube diameter was measured by UV absorption spectroscopy, and ozone vibrational temperature TV was found comparing the calculated ab initio absorption spectra with the experimental ones. It has been shown that the O3 production mainly occurs on a tube surface whereas ozone is lost in the tube centre where in contrast the electron and oxygen atom densities are maximal. Two models were used to analyse the obtained results. The first one is a kinetic 1D model for the processes occurring near the tube walls with the participation of the main particles: O(3P), O2, O2(1Δg) and O3 molecules in different vibrational states. The agreement of O3 and O(3P) density profiles and TV calculated in the model with observed ones was reached by varying the single model parameter—ozone production probability (\\gamma_{O_{3}}) on the quartz tube surface on the assumption that O3 production occurs mainly in the surface recombination of physisorbed O(3P) and O2. The phenomenological model of the surface processes with the participation of oxygen atoms and molecules including singlet oxygen molecules was also considered to analyse \\gamma_{O_{3}} data obtained in the kinetic model. A good agreement between the experimental data and the data of both models—the kinetic 1D model and the phenomenological surface model—was obtained in the full range of the studied conditions that allowed consideration of the ozone surface production mechanism in more detail. The important role of singlet oxygen in ozone surface production was shown. The O3 surface production rate directly depends on the density of physisorbed oxygen atoms and molecules and can be high with increasing pressure and energy inputted into plasma while simultaneously keeping the surface temperature low enough. Using the special discharge cell design, such an approach opens up the

  5. VIEW OF MANEUVER BOAT No. 2 AND CHANOINE WICKETS FROM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF MANEUVER BOAT No. 2 AND CHANOINE WICKETS FROM DAM GATE STRUCTURE. MANEUVER BOAT No. 2 IN BACKGROUND. LOOKING WEST NORTHWEST. - Illinois Waterway, Peoria Lock and Dam, 1071 Wesley Road, Creve Coeur, Tazewell County, IL

  6. Increased root oxygen uptake in pea plants responding to non-self neighbors.

    PubMed

    Meier, Ina Christin; Angert, Alon; Falik, Omer; Shelef, Oren; Rachmilevitch, Shimon

    2013-09-01

    Recent studies have demonstrated that plants alter root growth and decrease competition with roots of the same individual (self); however, the physiological traits accompanying this response are still widely unknown. In this study, we investigated the effect of root identity on gas exchange in the model species pea (Pisum sativum L.). Split-root plants were planted so that each pot contained either two roots of the same plant (self) or of two different plants (non-self), and the responses of biomass, photosynthesis, and respiration were measured. The photosynthetic rate was not affected by the identity of the root neighbor. We found a reduction of leaf dark respiration by half, accompanied by an increase in nocturnal root respiration by 29 % in plants neighboring with non-self. The activity of the alternative oxidase (AOX) pathway increased when plants responded to non-self neighbors. The increased activity of AOX in plants responding to non-self indicates carbon imbalances in roots, possibly as a consequence of increased root exudation and communication between individuals. If such an effect occurs more widely, it may change the assumptions made for the quantity of respiration as used in carbon budget models.

  7. Maneuver Warfare revisited: a plea for balance

    SciTech Connect

    Hamilton, M,R.

    1986-04-01

    This paper is a plea for balance in the current pursuit of understanding of the concept and the teaching of Maneuver Warfare. It specifically addresses the need for a more-complete analysis of some of the more-common historical examples commonly offered as examples of the supremecy of Maneuver Warfare. The paper in no way disagrees with the desirability of conducting the kinds of operations associated with the ill-defined concepts offered by advocates of Maneuver Warfare but suggests that the desirable results of historical battles may be too readily ascribed to the dynamic, offensive actions of the victorious side. Secondly, the paper points out the lack of utility and applicability of some common buzzwords being used in today's Army. Specifically assailed is the concept of turning within a decision cycle. The paper describes the reasons that this commonly used phrase has little applicability to ground warfare. Finally, the paper mentions the tendency for the Maneuver Warfare camp to cloud discussion of doctrine in a kind of intellectualism and elitism that has no use in forming the necessary consensus demanded by doctrine.

  8. 75 FR 49815 - Maneuvering Speed Limitation Statement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-16

    ... (NPRM), Notice No. 09-10, published in the Federal Register on September 4, 2009 (74 FR 45777). In the.../fr/index.html . You can also get a copy by sending a request to the Federal Aviation Administration... Federal Aviation Administration 14 CFR Part 25 RIN 2120-AJ21 Maneuvering Speed Limitation Statement...

  9. 14 CFR 23.423 - Maneuvering loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    .../sec2) Nose-up pitching 1.0 +39nm÷V×(nm−1.5) Nose-down pitching nm −39nm÷V×(nm−1.5) where— (1) nm... exceeding the limit maneuvering load factor. The total horizontal surface load for both nose-up and...

  10. 14 CFR 23.423 - Maneuvering loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    .../sec2) Nose-up pitching 1.0 +39nm÷V×(nm−1.5) Nose-down pitching nm −39nm÷V×(nm−1.5) where— (1) nm... exceeding the limit maneuvering load factor. The total horizontal surface load for both nose-up and...

  11. 14 CFR 23.423 - Maneuvering loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    .../sec2) Nose-up pitching 1.0 +39nm÷V×(nm−1.5) Nose-down pitching nm −39nm÷V×(nm−1.5) where— (1) nm... exceeding the limit maneuvering load factor. The total horizontal surface load for both nose-up and...

  12. 32 CFR 644.137 - Maneuver agreements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... with the exercise objectives and the force elements which participate. The Corps participates in the...), and United States Army Forces, Readiness Command (USCINCARRED) on acquisition of maneuver rights for... camp sites, field hospital sites and supply dumps), and buildings needed for warehouses, ordnance...

  13. Optimizing interplanetary trajectories with deep space maneuvers

    NASA Astrophysics Data System (ADS)

    Navagh, John

    1993-09-01

    Analysis of interplanetary trajectories is a crucial area for both manned and unmanned missions of the Space Exploration Initiative. A deep space maneuver (DSM) can improve a trajectory in much the same way as a planetary swingby. However, instead of using a gravitational field to alter the trajectory, the on-board propulsion system of the spacecraft is used when the vehicle is not near a planet. The purpose is to develop an algorithm to determine where and when to use deep space maneuvers to reduce the cost of a trajectory. The approach taken to solve this problem uses primer vector theory in combination with a non-linear optimizing program to minimize Delta(V). A set of necessary conditions on the primer vector is shown to indicate whether a deep space maneuver will be beneficial. Deep space maneuvers are applied to a round trip mission to Mars to determine their effect on the launch opportunities. Other studies which were performed include cycler trajectories and Mars mission abort scenarios. It was found that the software developed was able to locate quickly DSM's which lower the total Delta(V) on these trajectories.

  14. Hybrid guidance for maneuvering flight vehicles

    NASA Astrophysics Data System (ADS)

    Ling, Dehai

    1992-02-01

    This article puts forward one type of guidance option related to the maneuver programming of reentering flight vehicles. The option in question makes use of a radiation sensing system, precisely determining the location of the starting point of the reentering flight vehicle. Use is also made of strap-on type inertial guidance systems to control the impact points of flight vehicles. Maneuvering flight is an important direction in the development of the technology of strategic flight vehicles. It is possible to use it in sudden defense, adding programming, raising precision, and recovery. Maneuvering flight tests are capable of giving complete checks in all such areas as flight vehicle propulsion systems, materials structure, heat resistance systems, stability, guidance circuits, and attitude control systems. It is capable of carrying out experiments on different technological levels. Options which are relatively simple and easy to carry out are to make the reentering flight vehicle, within the longitudinal plane, fly maneuvers according to preset programs. Going through precise inertial guidance or celestial-inertial guidance systems, guidance is carried out on the flight vehicle in the main power stage, with controls and corrections to the free section flight orbital plane, such that the trajectory is capable of entering into the predicted reentry corridor. As far as initial flight tests are concerned, it is possible to make use of inertial guidance systems which already exist, relaxing the requirements for launch plane controls and lateral impact point deviations.

  15. 46 CFR 131.990 - Maneuvering characteristics.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS... condition of loading, assuming the following: (1) Calm weather—wind 10 knots or less, calm sea. (2) No... maneuvering information is based, are varied: (i) Calm weather—wind 10 knots or less, calm sea. (ii)...

  16. Decreased muscle oxygenation and increased arterial blood flow in the non-exercising limb during leg exercise.

    PubMed

    Shiroishi, Kiyoshi; Kime, Ryotaro; Osada, Takuya; Murase, Norio; Shimomura, Kousuke; Katsumura, Toshihito

    2010-01-01

    We evaluated arterial blood flow, muscle tissue oxygenation and muscle metabolism in the non-exercising limb during leg cycling exercise. Ten healthy male volunteers performed a graded leg cycling exercise at 0, 40, 80, 120 and 160 watts (W) for 5 min each. Tissue oxygenation index (TOI) of the non-exercising left forearm muscle was measured using a near-infrared spatially resolved spectroscopy (NIR(SRS)), and non-exercising forearm blood flow ((NONEX)FBF) in the brachial artery was also evaluated by a Doppler ultrasound system. We also determined O(2) consumption of the non-exercising forearm muscle (NONEXV(O)(2mus)) by the rate of decrease in O(2)Hb during arterial occlusion at each work rate. TOI was significantly decreased at 160 W (p < 0.01) compared to the baseline. The (NONEX)V(O)(2mus) at each work rate was not significantly increased. In contrast, (NONEX)FBF was significantly increased at 120 W (p < 0.05) and 160 W (p < 0.01) compared to the baseline. These results suggest that the O(2) supply to the non-exercising muscle may be reduced, even though (NONEX)FBF increases at high work rates during leg cycling exercise.

  17. Combined increases in mitochondrial cooperation and oxygen photoreduction compensate for deficiency in cyclic electron flow in Chlamydomonas reinhardtii.

    PubMed

    Dang, Kieu-Van; Plet, Julie; Tolleter, Dimitri; Jokel, Martina; Cuiné, Stéphan; Carrier, Patrick; Auroy, Pascaline; Richaud, Pierre; Johnson, Xenie; Alric, Jean; Allahverdiyeva, Yagut; Peltier, Gilles

    2014-07-01

    During oxygenic photosynthesis, metabolic reactions of CO2 fixation require more ATP than is supplied by the linear electron flow operating from photosystem II to photosystem I (PSI). Different mechanisms, such as cyclic electron flow (CEF) around PSI, have been proposed to participate in reequilibrating the ATP/NADPH balance. To determine the contribution of CEF to microalgal biomass productivity, here, we studied photosynthesis and growth performances of a knockout Chlamydomonas reinhardtii mutant (pgrl1) deficient in PROTON GRADIENT REGULATION LIKE1 (PGRL1)-mediated CEF. Steady state biomass productivity of the pgrl1 mutant, measured in photobioreactors operated as turbidostats, was similar to its wild-type progenitor under a wide range of illumination and CO2 concentrations. Several changes were observed in pgrl1, including higher sensitivity of photosynthesis to mitochondrial inhibitors, increased light-dependent O2 uptake, and increased amounts of flavodiiron (FLV) proteins. We conclude that a combination of mitochondrial cooperation and oxygen photoreduction downstream of PSI (Mehler reactions) supplies extra ATP for photosynthesis in the pgrl1 mutant, resulting in normal biomass productivity under steady state conditions. The lower biomass productivity observed in the pgrl1 mutant in fluctuating light is attributed to an inability of compensation mechanisms to respond to a rapid increase in ATP demand. PMID:24989042

  18. The mountains that triggered the Late Neoproterozoic increase in oxygen: The Second Great Oxidation Event

    NASA Astrophysics Data System (ADS)

    Campbell, Ian H.; Squire, Richard J.

    2010-08-01

    The consensus view is that the O 2 concentration of the Archean atmosphere was very low and that it rose to its present level of 21% in a series of steps, two of which dwarf the others in importance. The first, known as the Great Oxidation Event, occurred at ˜2.4 Ga. It involved an increase in the relative abundance of O 2, which has been estimated at three orders of magnitude, and it is important because it led to the first surface weathering. The second, although less important in relative terms, involved the addition of 9 × 10 17 kg of O 2 to the atmosphere, at least ten times as much as that required to produce the Great Oxidation Event. Its importance lies in the fact that it correlates with the rise of animals in the Ediacaran and Early Cambrian periods. Although it is widely accepted that an increase in atmospheric O 2 facilitated the appearance of animals at ˜575 Ma, followed by the Cambrian Explosion ˜50 Myr later, the cause of this increase remains controversial. We show that the surge in the O 2 level near the Precambrian-Cambrian boundary correlates with major episodes of continent-continent collision associated with Gondwana's amalgamation, including convergence between East and West Gondwana, which produced the 8000-km-long Transgondwanan Supermountains. The eroded roots of these mountains include the oldest lawsonite-bearing blueschists and eclogites, and ultra high-pressure metamorphic rocks. The sudden appearance of these low-thermal gradient, high-pressure metamorphic rocks implies that the Gondwanan orogenic zones were cooler and stronger than those associated with the assembly of earlier supercontinents and therefore capable of supporting higher mountains. There is a log-linear relationship between relief and erosion rate, and a linear relationship between sedimentation rate and organic C burial. Taken together these two relationships imply a log-linear relationship between relief and C sequestration. We suggest that the Gondwanan

  19. 23 CFR 660.517 - Maneuver area roads.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Maneuver area roads. 660.517 Section 660.517 Highways... PROGRAMS (DIRECT FEDERAL) Defense Access Roads § 660.517 Maneuver area roads. (a) Claims by a highway agency for costs incurred to restore, to their former condition, roads damaged by maneuvers involving...

  20. 23 CFR 660.517 - Maneuver area roads.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Maneuver area roads. 660.517 Section 660.517 Highways... PROGRAMS (DIRECT FEDERAL) Defense Access Roads § 660.517 Maneuver area roads. (a) Claims by a highway agency for costs incurred to restore, to their former condition, roads damaged by maneuvers involving...

  1. 23 CFR 660.517 - Maneuver area roads.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Maneuver area roads. 660.517 Section 660.517 Highways... PROGRAMS (DIRECT FEDERAL) Defense Access Roads § 660.517 Maneuver area roads. (a) Claims by a highway agency for costs incurred to restore, to their former condition, roads damaged by maneuvers involving...

  2. 23 CFR 660.517 - Maneuver area roads.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Maneuver area roads. 660.517 Section 660.517 Highways... PROGRAMS (DIRECT FEDERAL) Defense Access Roads § 660.517 Maneuver area roads. (a) Claims by a highway agency for costs incurred to restore, to their former condition, roads damaged by maneuvers involving...

  3. 23 CFR 660.517 - Maneuver area roads.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Maneuver area roads. 660.517 Section 660.517 Highways... PROGRAMS (DIRECT FEDERAL) Defense Access Roads § 660.517 Maneuver area roads. (a) Claims by a highway agency for costs incurred to restore, to their former condition, roads damaged by maneuvers involving...

  4. 14 CFR 23.1507 - Operating maneuvering speed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Operating maneuvering speed. 23.1507... Limitations and Information § 23.1507 Operating maneuvering speed. The maximum operating maneuvering speed, VO, must be established as an operating limitation. VO is a selected speed that is not greater than...

  5. 14 CFR 23.1507 - Operating maneuvering speed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Operating maneuvering speed. 23.1507... Limitations and Information § 23.1507 Operating maneuvering speed. The maximum operating maneuvering speed, VO, must be established as an operating limitation. VO is a selected speed that is not greater than...

  6. 14 CFR 23.1507 - Operating maneuvering speed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Operating maneuvering speed. 23.1507... Limitations and Information § 23.1507 Operating maneuvering speed. The maximum operating maneuvering speed, VO, must be established as an operating limitation. VO is a selected speed that is not greater than...

  7. 14 CFR 23.1507 - Operating maneuvering speed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Operating maneuvering speed. 23.1507... Limitations and Information § 23.1507 Operating maneuvering speed. The maximum operating maneuvering speed, VO, must be established as an operating limitation. VO is a selected speed that is not greater than...

  8. 14 CFR 23.1507 - Operating maneuvering speed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Operating maneuvering speed. 23.1507... Limitations and Information § 23.1507 Operating maneuvering speed. The maximum operating maneuvering speed, VO, must be established as an operating limitation. VO is a selected speed that is not greater than...

  9. 14 CFR 23.1567 - Flight maneuver placard.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flight maneuver placard. 23.1567 Section 23... Information Markings and Placards § 23.1567 Flight maneuver placard. (a) For normal category airplanes, there... the approved acrobatic maneuvers and the recommended entry airspeed for each. If inverted...

  10. 14 CFR 25.333 - Flight maneuvering envelope.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flight maneuvering envelope. 25.333 Section... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Flight Maneuver and Gust Conditions § 25.333 Flight maneuvering envelope. (a) General. The strength requirements must be met at each combination...

  11. 14 CFR 23.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Limit maneuvering load factors. 23.337... Flight Loads § 23.337 Limit maneuvering load factors. (a) The positive limit maneuvering load factor n... not be less than— (1) 0.4 times the positive load factor for the normal utility and...

  12. 14 CFR 25.1531 - Maneuvering flight load factors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maneuvering flight load factors. 25.1531... Operating Limitations § 25.1531 Maneuvering flight load factors. Load factor limitations, not exceeding the positive limit load factors determined from the maneuvering diagram in § 25.333(b), must be established....

  13. 14 CFR 25.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit maneuvering load factors. 25.337... Conditions § 25.337 Limit maneuvering load factors. (a) Except where limited by maximum (static) lift... maneuvering load factors prescribed in this section. Pitching velocities appropriate to the corresponding...

  14. A feedback linearization approach to orbital maneuvers

    NASA Astrophysics Data System (ADS)

    Lee, Sanguk

    New methods for obtaining optimal orbital maneuvers of a space vehicle in total velocity change are described and applied. The elegance of Lambert's Theorem is combined with feedback linearization and linear optimal control to obtain solutions to nonlinear orbital maneuver problems. In particular, geocentric orbital maneuvers with finite-thrust acceleration are studied. The full nonlinear equations of motion are transformed exactly into a controllable linear set in Brunovsky canonical form by using feedback linearization and choosing the position vector as the fully observable output vector. These equations are used to pose a linear optimal tracking problem with a solution to the Lambert's impulsive-thrust two-point boundary-value problem as the reference orbit. The same procedure is used to force the space vehicle to follow a linear analytical solution to the continuous low-thrust orbital maneuver problem between neighboring orbits. Limits on thrust magnitudes are enforced by adjusting the weights on the states in the performance index, which is chosen to be the sum of integrals of the square sum of new control variables and the square sum of state variable errors from the reference trajectory. For comparison purpose, the feedback linearized equations are used to obtain a simple closed-form solution to an orbital maneuver problem without the use of a reference trajectory. In this case, the performance index was chosen as the integral of the square sum of new control variables only. Three different examples, coplanar rendezvous between neighboring orbits, large coplanar orbit transfer, and non-coplanar orbit transfer, are used to show the advantages of using the new methods introduced in this dissertation. The minimum-eccentricity orbit, Hohmann transfer orbit, and minimum energy orbit were used in turn as the reference trajectories. The principal problems encountered in using the new methods are the choices of the proper reference trajectory, a suitable time

  15. Maternal Hypoxia Decreases Capillary Supply and Increases Metabolic Inefficiency Leading to Divergence in Myocardial Oxygen Supply and Demand

    PubMed Central

    Hauton, David; Al-Shammari, Abdullah; Gaffney, Eamonn A.; Egginton, Stuart

    2015-01-01

    Maternal hypoxia is associated with a decrease in left ventricular capillary density while cardiac performance is preserved, implying a mismatch between metabolism and diffusive exchange. We hypothesised this requires a switch in substrate metabolism to maximise efficiency of ATP production from limited oxygen availability. Rat pups from pregnant females exposed to hypoxia (FIO2=0.12) at days 10-20 of pregnancy were grown to adulthood and working hearts perfused ex vivo. 14C-labelled glucose and 3H-palmitate were provided as substrates and metabolism quantified from recovery of 14CO2 and 3H2O, respectively. Hearts of male offspring subjected to Maternal Hypoxia showed a 20% decrease in cardiac output (P<0.05), despite recording a 2-fold increase in glucose oxidation (P<0.01) and 2.5-fold increase (P<0.01) in palmitate oxidation. Addition of insulin to Maternal Hypoxic hearts, further increased glucose oxidation (P<0.01) and suppressed palmitate oxidation (P<0.05), suggesting preservation in insulin signalling in the heart. In vitro enzyme activity measurements showed that Maternal Hypoxia increased both total and the active component of cardiac pyruvate dehydrogenase (both P<0.01), although pyruvate dehydrogenase sensitivity to insulin was lost (NS), while citrate synthase activity declined by 30% (P<0.001) and acetyl-CoA carboxylase activity was unchanged by Maternal Hypoxia, indicating realignment of the metabolic machinery to optimise oxygen utilisation. Capillary density was quantified and oxygen diffusion characteristics examined, with calculated capillary domain area increased by 30% (P<0.001). Calculated metabolic efficiency decreased 4-fold (P<0.01) for Maternal Hypoxia hearts. Paradoxically, the decline in citrate synthase activity and increased metabolism suggest that the scope of individual mitochondria had declined, rendering the myocardium potentially more sensitive to metabolic stress. However, decreasing citrate synthase may be essential to preserve

  16. Comparative analysis between the alveolar recruitment maneuver and breath stacking technique in patients with acute lung injury

    PubMed Central

    Porto, Elias Ferreira; Tavolaro, Kelly Cristiani; Kumpel, Claudia; Oliveira, Fernanda Augusta; Sousa, Juciaria Ferreira; de Carvalho, Graciele Vieira; de Castro, Antonio Adolfo Mattos

    2014-01-01

    Objective To compare the effectiveness of the alveolar recruitment maneuver and the breath stacking technique with respect to lung mechanics and gas exchange in patients with acute lung injury. Methods Thirty patients were distributed into two groups: Group 1 - breath stacking; and Group 2 - alveolar recruitment maneuver. After undergoing conventional physical therapy, all patients received both treatments with an interval of 1 day between them. In the first group, the breath stacking technique was used initially, and subsequently, the alveolar recruitment maneuver was applied. Group 2 patients were initially subjected to alveolar recruitment, followed by the breath stacking technique. Measurements of lung compliance and airway resistance were evaluated before and after the use of both techniques. Gas analyses were collected before and after the techniques were used to evaluate oxygenation and gas exchange. Results Both groups had a significant increase in static compliance after breath stacking (p=0.021) and alveolar recruitment (p=0.03), but with no significant differences between the groups (p=0.95). The dynamic compliance did not increase for the breath stacking (p=0.22) and alveolar recruitment (p=0.074) groups, with no significant difference between the groups (p=0.11). The airway resistance did not decrease for either groups, i.e., breath stacking (p=0.91) and alveolar recruitment (p=0.82), with no significant difference between the groups (p=0.39). The partial pressure of oxygen increased significantly after breath stacking (p=0.013) and alveolar recruitment (p=0.04), but there was no significant difference between the groups (p=0.073). The alveolar-arterial O2 difference decreased for both groups after the breath stacking (p=0.025) and alveolar recruitment (p=0.03) interventions, and there was no significant difference between the groups (p=0.81). Conclusion Our data suggest that the breath stacking and alveolar recruitment techniques are effective in

  17. Increase of reactive oxygen species by desferrioxamine during experimental Chagas' disease

    PubMed Central

    Francisco, Amanda Fortes; de Abreu Vieira, Paula Melo; Arantes, Jerusa Marilda; Silva, Maisa; Pedrosa, Maria Lúcia; Elói-Santos, Silvana Maria; Martins-Filho, Olindo Assis; Teixeira-Carvalho, Andréa; Araújo, Márcio Sobreira Silva; Tafuri, Washington Luiz; Carneiro, Cláudia Martins

    2010-01-01

    Oxidative stress is common in inflammatory processes associated with many diseases including Chagas' disease. The aim of the present study was to evaluate, in a murine model, biomarkers of oxidative stress together with components of the antioxidant system in order to provide an overview of the mechanism of action of the iron chelator desferrioxamine (DFO). The study population comprised 48 male Swiss mice, half of which were treated daily by intraperitoneal injection of DFO over a 35-day period, while half were administered sterile water in a similar manner. On the 14th day of the experiment, 12 DFO-treated mice and an equal number of untreated mice were experimentally infected with Trypanosoma cruzi. Serum concentrations of nitric oxide and superoxide dismutase and hepatic levels of total glutathione, thiobarbituric acid reactive species and protein carbonyl, were determined on days 0, 7, 14 and 21 post-infection. The results obtained revealed that DFO enhances antioxidant activity in the host but also increases oxidative stress, indicating that the mode of action of the drug involves a positive contribution to the host together with an effect that is not beneficial to the parasite. PMID:20663295

  18. Effect of Conflict Resolution Maneuver Execution Delay on Losses of Separation

    NASA Technical Reports Server (NTRS)

    Cone, Andrew C.

    2010-01-01

    This paper examines uncertainty in the maneuver execution delay for data linked conflict resolution maneuvers. This uncertainty could cause the previously cleared primary conflict to reoccur or a secondary conflict to appear. Results show that the likelihood of a primary conflict reoccurring during a horizontal conflict resolution maneuver increases with larger initial turn-out angles and with shorter times until loss of separation. There is also a significant increase in the probability of a primary conflict reoccurring when the time until loss falls under three minutes. Increasing horizontal separation by an additional 1.5 nmi lowers the risk, but does not completely eliminate it. Secondary conflicts were shown to have a small probability of occurring in all tested configurations.

  19. Sonic boom focal zones due to tactical aircraft maneuvers

    NASA Astrophysics Data System (ADS)

    Plotkin, Kenneth J.

    1990-10-01

    A study has been conducted of the focal zone 'superbooms' associated with tactical maneuvers of military supersonic aircraft. Focal zone footprints were computed for 21 tactical maneuvers: two for the SR-71 and 19 for fighters engaged in air combat maneuver (ACM) training. These footprints provide quantitative results which may be used for environmental planning. A key finding of this study is that focus factors and footprint areas for high-g fighter maneuvers are substantially smaller than those for gentle maneuvers associated with larger aircraft.

  20. Gymnosperms have increased capacity for electron leakage to oxygen (Mehler and PTOX reactions) in photosynthesis compared with angiosperms.

    PubMed

    Shirao, Masayoshi; Kuroki, Shu; Kaneko, Kaoru; Kinjo, Yuriko; Tsuyama, Michito; Förster, Britta; Takahashi, Shunichi; Badger, Murray R

    2013-07-01

    Oxygen plays an important role in photosynthesis by participating in a number of O2-consuming reactions. O2 inhibits CO2 fixation by stimulating photorespiration, thus reducing plant production. O2 interacts with photosynthetic electron transport in the chloroplasts' thylakoids in two main ways: by accepting electrons from PSI (Mehler reaction); and by accepting electrons from reduced plastoquinone (PQ) mediated by the plastid terminal oxidase (PTOX). In this study, we show, using 101 plant species, that there is a difference in the potential for photosynthetic electron flow to O2 between angiosperms and gymnosperms. We found, from measurements of Chl fluorescence and leaf absorbance at 830 nm, (i) that electron outflow from PSII, as determined by decay kinetics of Chl fluorescence after application of a saturating light pulse, is more rapid in gymnosperms than in angiosperms; (ii) that the reaction center Chl of PSI (P700) is rapidly and highly oxidized in gymnosperms during induction of photosynthesis; and (iii) that these differences are dependent on oxygen. Finally, rates of O2 uptake measured by mass spectrometry in the absence of photorespiration were significantly promoted by illumination in dark-adapted leaves of gymnosperms, but not in those of angiosperms. The light-stimulated O2 uptake was around 10% of the maximum O2 evolution in gymnosperms and 1% in angiosperms. These results suggest that gymnosperms have increased capacity for electron leakage to oxygen in photosynthesis compared with angiosperms. The involvement of the Mehler reaction and PTOX in the electron flow to O2 is discussed.

  1. Flaxseed oil increases aortic reactivity to phenylephrine through reactive oxygen species and the cyclooxygenase-2 pathway in rats

    PubMed Central

    2014-01-01

    Background Flaxseed oil has the highest concentration of omega-3 α-linolenic acid, which has been associated with cardiovascular benefit. However, the mechanism underlying the vascular effects induced through flaxseed oil is not well known. Thus, in the present study, we investigated the effects of flaxseed oil on vascular function in isolated rat aortic rings. Methods Wistar rats were treated daily with flaxseed oil or a control (mineral oil) intramuscular (i.m.) for fifteen days. Isolated aortic segments were used to evaluate cyclooxygenase-2 (COX-2) protein expression, superoxide anion levels and vascular reactivity experiments. Results Flaxseed oil treatment increased the vasoconstrictor response of aortic rings to phenylephrine. Endothelium removal increased the response to phenylephrine in aortic segments isolated from both groups, but the effect was smaller in the treated group. L-NAME incubation similarly increased the phenylephrine response in segments from both groups. The TXA2 synthase inhibitor furegrelate, the selective COX-2 inhibitor NS 398, the TP receptor antagonist SQ 29.548, the reactive oxygen species (ROS) scavenger apocynin, the superoxide anion scavengers tiron and the phospholipase A2 inhibitor dexamethasone partially reversed the flaxseed oil-induced increase in reactivity to phenylephrine. Conclusions These findings suggest that flaxseed oil treatment increased vascular reactivity to phenylephrine through an increase in ROS production and COX-2-derived TXA2 production. The results obtained in the present study provide new insight into the effects of flaxseed oil treatment (i.m.) on vascular function. PMID:24993607

  2. Maneuver tracking using an adaptive Gaussian sum technique

    NASA Astrophysics Data System (ADS)

    Stubberud, Stephen C.; Kramer, Kathleen A.

    2005-03-01

    The best method to track through a maneuver is to know the motion model of the maneuvering target. Unfortunately, a priori knowledge of the maneuver is not usually known. If the motion model of the maneuver can be estimated quickly from the measurements then the resulting track estimate will be better than the a priori static model. An adaptive function approximation technique to improve the motion model while tracking is analyzed for its potential to track through various maneuvers. The basic function approximation technique is that of a Gaussian sum. The Gaussian sum approximates the function which represents the error between the initial static model and the actual model of the maneuver. The parameters of the Gaussian sum are identified on-line using a Kalman filter identification scheme. This scheme, used in conjunction with a Kalman filter tracker, creates a coupled technique that can improve the motion model quickly. This adaptive Gaussian sum approach to maneuver tracking has its performance analyzed for three maneuvers. These maneuvers include a maneuvering ballistic target, a target going through an s-curve, and real target with a multiple racetrack flight path. The results of these test cases demonstrate the capabilities of this approach to track maneuvering targets.

  3. Flow enhances photosynthesis in marine benthic autotrophs by increasing the efflux of oxygen from the organism to the water.

    PubMed

    Mass, Tali; Genin, Amatzia; Shavit, Uri; Grinstein, Mor; Tchernov, Dan

    2010-02-01

    Worldwide, many marine coastal habitats are facing rapid deterioration due in part to human-driven changes in habitat characteristics, including changes in flow patterns, a factor known to greatly affect primary production in corals, algae, and seagrasses. The effect of flow traditionally is attributed to enhanced influx of nutrients and dissolved inorganic carbon (DIC) across the benthic boundary layer from the water to the organism however, here we report that the organism's photosynthetic response to changes in the flow is nearly instantaneous, and that neither nutrients nor DIC limits this rapid response. Using microelectrodes, dual-pulse amplitude-modulated fluorometry, particle image velocimetry, and real time mass-spectrometry with the common scleractinian coral Favia veroni, the alga Gracilaria cornea, and the seagrass Halophila stipulacea, we show that this augmented photosynthesis is due to flow-driven enhancement of oxygen efflux from the organism to the water, which increases the affinity of the RuBisCO to CO(2). No augmentation of photosynthesis was found in the absence of flow or when flow occurred, but the ambient concentration of oxygen was artificially elevated. We suggest that water motion should be considered a fundamental factor, equivalent to light and nutrients, in determining photosynthesis rates in marine benthic autotrophs.

  4. Down regulation of Kv3.4 channels by chronic hypoxia increases acute oxygen sensitivity in rabbit carotid body

    PubMed Central

    Kääb, Stefan; Miguel-Velado, Eduardo; López-López, José Ramón; Pérez-García, M Teresa

    2005-01-01

    The carotid body (CB) chemoreceptors participate in the ventilatory responses to acute and chronic hypoxia (CH). Arterial hypoxaemia increases breathing within seconds, and CB chemoreceptors are the principal contributors to this reflex hyperventilatory response. Acute hypoxia induces depolarization of CB chemoreceptors by inhibiting certain K+ channels, but the role of these channels in CH, as in high-altitude acclimatization, is less known. Here we explored the effects of prolonged (24–48 h) hypoxic exposure of rabbit CB chemoreceptor cells in primary cultures on the voltage-dependent K+ currents and on their response to acute hypoxia. We found that CH induces a decrease in the amplitude of outward K+ currents due to a reduction in a fast-inactivating BDS- and highly TEA-sensitive component of the current. In spite of this effect, acute hypoxic inhibition of K+ currents is increased in CH cultures, as well as hypoxia-induced depolarization. These data suggest that downregulation of this component (that does not contribute to the oxygen-sensitive K+ current (IKO2)) participates in the hypoxic sensitization. Pharmacological, immunocytochemical and quantitative PCR (qPCR) experiments demonstrate that CH-induced decrease in outward K+ currents is due to a downregulation of the expression of Kv3.4 channels. Taken together, our results suggest that CH sensitization in rabbit CB could be achieved by an increase in the relative contribution of IKO2 to the outward K+ current as a consequence of the decreased expression of the oxygen-insensitive component of the current. We conclude that acute and chronic hypoxia can exert their effects acting on different molecular targets. PMID:15890707

  5. Rendezvous radar for the orbital maneuvering vehicle

    NASA Technical Reports Server (NTRS)

    Locke, John W.; Olds, Keith A.; Quaid, Thomas

    1991-01-01

    The Rendezvous Radar Set (RRS) was designed at Motorola's Strategic Electronics Division in Chandler, Arizona, to be a key subsystem aboard NASA's Orbital Maneuvering Vehicle (OMV). The unmanned OMV, which was under development at TRW's Federal Systems Division in Redondo Beach, California, was designed to supplement the Shuttle's satellite delivery, retrieval, and maneuvering activities. The RRS was to be used to locate and then provide the OMV with vectoring information to the target satellite (or Shuttle or Space Station) to aid the OMV in making a minimum fuel consumption approach and rendezvous. The OMV development program was halted by NASA in 1990 just as parts were being ordered for the RRS engineering model. The paper presented describes the RRS design and then discusses new technologies, either under development or planned for development at Motorola, that can be applied to radar or alternative sensor solutions for the Automated Rendezvous and Capture problem.

  6. Force oscillations simulating breathing maneuvers do not prevent force adaptation.

    PubMed

    Pascoe, Chris; Jiao, Yuekan; Seow, Chun Y; Paré, Peter D; Bossé, Ynuk

    2012-07-01

    Airway inflammation in patients with asthma exposes the airway smooth muscle (ASM) to a variety of spasmogens. These spasmogens increase ASM tone, which can lead to force adaptation. Length oscillations of ASM, which occur in vivo due to breathing maneuvers, can attenuate force adaptation. However, in the presence of tone, the force oscillations required to achieve these length oscillations may be unphysiologic (i.e., magnitude greater than the ones achieved due to the swings in transpulmonary pressure required for breathing). In the present study, we applied force oscillations simulating the tension oscillations experienced by the wall of a fourth-generation airway during tidal breathing with or without deep inspirations (DI) to ASM. The goal was to investigate whether force adaptation occurs in conditions mimicking breathing maneuvers. Tone was induced by carbachol (average, 20 nM), and the force-generating capacity of the ASM was assessed at 5-minute intervals before and after carbachol administration using electrical field stimulations (EFS). The results show that force oscillations applied before the introduction of tone had a small effect on the force produced by EFS (declined to 96.8% [P > 0.05] and 92.3% [P < 0.05] with and without DI, respectively). The tone induced by carbachol transiently decreased after a DI and declined significantly (P < 0.05) due to tidal breathing oscillations (25%). These force oscillations did not prevent force adaptation (gain of force of 11.2 ± 2.2 versus 13.5 ± 2.7 and 11.2 ± 3.0% in static versus dynamic conditions with or without DI, respectively). The lack of effect of simulated breathing maneuvers on force adaptation suggests that this gain in ASM force may occur in vivo and could contribute to the development of airway hyperresponsiveness. PMID:22323367

  7. The Orbital Maneuvering Vehicle - A new capability

    NASA Technical Reports Server (NTRS)

    Arcilesi, Charles J.; Holliman, Charles T.

    1988-01-01

    NASA's Orbital Maneuvering Vehicle (OMV) is a reusable remotely-controlled spacecraft for support of orbiting platforms through such functions as satellite delivery, satellite retrieval, satellite reboost, controlled satellite deorbit, satellite inspection, and subsatellite missions. The OMV will be a critical component of the Space Station program's operational scenario; it will be able to operate either from the Space Shuttle Orbiter or the Space Station, and can also be space-based. The maiden flight of the first OMV is projected for 1993.

  8. Hydrodynamics of maneuvering bodies: LDRD final report

    SciTech Connect

    Kempka, S.N.; Strickland, J.H.

    1994-01-01

    The objective of the ``Hydrodynamics of Maneuvering Bodies`` LDRD project was to develop a Lagrangian, vorticity-based numerical simulation of the fluid dynamics associated with a maneuvering submarine. Three major tasks were completed. First, a vortex model to simulate the wake behind a maneuvering submarine was completed, assuming the flow to be inviscid and of constant density. Several simulations were performed for a dive maneuver, each requiring less than 20 cpu seconds on a workstation. The technical details of the model and the simulations are described in a separate document, but are reviewed herein. Second, a gridless method to simulate diffusion processes was developed that has significant advantages over previous Lagrangian diffusion models. In this model, viscous diffusion of vorticity is represented by moving vortices at a diffusion velocity, and expanding the vortices as specified by the kinematics for a compressible velocity field. This work has also been documented previously, and is only reviewed herein. The third major task completed was the development of a vortex model to describe inviscid internal wave phenomena, and is the focus of this document. Internal wave phenomena in the stratified ocean can affect an evolving wake, and thus must be considered for naval applications. The vortex model for internal wave phenomena includes a new formulation for the generation of vorticity due to fluid density variations, and a vortex adoption algorithm that allows solutions to be carried to much longer times than previous investigations. Since many practical problems require long-time solutions, this new adoption algorithm is a significant step toward making vortex methods applicable to practical problems. Several simulations are described and compared with previous results to validate and show the advantages of the new model. An overview of this project is also included.

  9. Hydrodynamics of maneuvering bodies: LDRD Final Report

    NASA Astrophysics Data System (ADS)

    Kempka, S. N.; Strickland, J. H.

    1994-01-01

    The objective of the 'Hydrodynamics of Maneuvering Bodies' LDRD project was to develop a Lagrangian, vorticity-based numerical simulation of the fluid dynamics associated with a maneuvering submarine. Three major tasks were completed. First, a vortex model to simulate the wake behind a maneuvering submarine was completed, assuming the flow to be inviscid and of constant density. Several simulations were performed for a dive maneuver, each requiring less than 20 cpu seconds on a workstation. The technical details of the model and the simulations are described in a separate document, but are reviewed herein. Second, a gridless method to simulate diffusion processes was developed that has significant advantages over previous Lagrangian diffusion models. In this model, viscous diffusion of vorticity is represented by moving vortices at a diffusion velocity, and expanding the vortices as specified by the kinematics for a compressible velocity field. This work was also documented previously and is only reviewed herein. The third major task completed was the development of a vortex model to describe inviscid internal wave phenomena and is the focus of this document. Internal wave phenomena in the stratified ocean can affect an evolving wake and thus, must be considered for naval applications. The vortex model for internal wave phenomena includes a new formulation for the generation of vorticity due to fluid density variations and a vortex adoption algorithm that allows solutions to be carried to much longer times than previous investigations. Since many practical problems require long-time solutions, this new adoption algorithm is a significant step toward making vortex methods applicable to practical problems. Several simulations are described and compared with previous results to validate and show the advantages of the new model. An overview of this project is also included.

  10. Identifying tacit strategies in aircraft maneuvers

    NASA Technical Reports Server (NTRS)

    Lewis, Charles M.; Heidorn, P. B.

    1991-01-01

    Two machine-learning methods are presently used to characterize the avoidance strategies used by skilled pilots in simulated aircraft encounters, and a general framework for the characterization of the strategic components of skilled behavior via qualitative representation of situations and responses is presented. Descriptions of pilot maneuvers that were 'conceptually equivalent' were ascertained by a concept-learning algorithm in conjunction with a classifier system that employed a generic algorithm; satisficing and 'buggy' strategies were thereby revealed.

  11. Epstein-Barr virus infection induces bone resorption in apical periodontitis via increased production of reactive oxygen species.

    PubMed

    Jakovljevic, Aleksandar; Andric, Miroslav; Miletic, Maja; Beljic-Ivanovic, Katarina; Knezevic, Aleksandra; Mojsilovic, Slavko; Milasin, Jelena

    2016-09-01

    Chronic inflammatory processes in periapical tissues caused by etiological agents of endodontic origin lead to apical periodontitis. Apart from bacteria, two herpesviruses, Epstein-Barr virus (EBV) and Human cytomegalovirus (HCMV) are recognized as putative pathogens in apical periodontitis. Although previous reports suggest the involvement of EBV in the pathogenesis of apical periodontitis, its exact role in periapical bone resorption has not yet been fully elucidated. We hypothesize that EBV infection in apical periodontitis is capable of inducing periapical bone resorption via stimulation of reactive oxygen species (ROS) overproduction. Increased levels of ROS induce expression of receptor activator of nuclear factor kappa B (NF-κB) ligand (RANKL). RANKL binding to receptor activator of nuclear factor κB (RANK) present on the surface of preosteoclasts induces their maturation and activation which consequently leads to bone resorption. The potential benefit of antiviral and antioxidant-based therapies in periapical bone resorption treatment remains to be assessed. PMID:27515196

  12. Inhibition of Cancer Cell Proliferation by PPARγ is Mediated by a Metabolic Switch that Increases Reactive Oxygen Species Levels

    PubMed Central

    Srivastava, Nishi; Kollipara, Rahul K.; Singh, Dinesh K.; Sudderth, Jessica; Hu, Zeping; Nguyen, Hien; Wang, Shan; Humphries, Caroline G.; Carstens, Ryan; Huffman, Kenneth E.; DeBerardinis, Ralph J.; Kittler, Ralf

    2014-01-01

    SUMMARY The nuclear receptor peroxisome-proliferation activated receptor gamma (PPARγ), a transcriptional master regulator of glucose and lipid metabolism, inhibits the growth of several common cancers including lung cancer. In this study, we show that the mechanism by which activation of PPARγ inhibits proliferation of lung cancer cells is based on metabolic changes. We found that treatment with the PPARγ agonist pioglitazone triggers a metabolic switch that inhibits pyruvate oxidation and reduces glutathione levels. These PPARγ-induced metabolic changes result in a marked increase of reactive oxygen species (ROS) levels that lead to rapid hypophosphorylation of retinoblastoma protein (RB) and cell cycle arrest. The antiproliferative effect of PPARγ activation can be prevented by suppressing pyruvate dehydrogenase kinase 4 (PDK4) or β-oxidation of fatty acids in vitro and in vivo. Our proposed mechanism also suggests that metabolic changes can rapidly and directly inhibit cell cycle progression of cancer cells by altering ROS levels. PMID:25264247

  13. A wing concept for supersonic maneuvering

    NASA Technical Reports Server (NTRS)

    Mason, W. H.

    1983-01-01

    A theoretical and experimental program in which a wing concept for supersonic maneuvering was developed and then demonstrated experimentally in a series of wind tunnel tests is described. For the typical fighter wing, the problem of obtaining efficient lift at supersonic maneuvering C sub 's occurs due to development of a strong crossflow shock, and boundary layer separation. A natural means of achieving efficient supersonic maneuvering is based on controlling the non-linear inviscid crossflow on the wing in a manner analogous to the supercritical aerodynamic methods developed for transonic speeds. The application of supercritical aerodynamics to supersonic speeds is carried out using Supercritical Conical Camber (SC3). This report provides an aerodynamic analysis of the effort, with emphasis on wing design using non-linear aerodynamics. The substantial experimental data base is described in three separate wind tunnel reports, while two of the computer programs used in the work are also described in a separate report. Based on the development program it appears that a controlled supercritical crossflow can be obtained reliably on fighter-type wing planforms, with an associated drag due to lift reduction of about 20% projected using this concept.

  14. Aerodynamic Flow Control of a Maneuvering Airfoil

    NASA Astrophysics Data System (ADS)

    Brzozowski, Daniel P.; Culp, John; Glezer, Ari

    2010-11-01

    The unsteady aerodynamic forces and moments on a maneuvering, free-moving airfoil are varied in wind tunnel experiments by controlling vorticity generation/accumulation near the surface using hybrid synthetic jet actuators. The dynamic characteristics of the airfoil that is mounted on a 2-DOF traverse are controlled using position and attitude feedback loops that are actuated by servo motors. Bi-directional changes in the pitching moment are induced using controllable trapped vorticity concentrations on the suction and pressure surfaces near the trailing edge. The dynamic coupling between the actuation and the time-dependent flow field is characterized using simultaneous force and velocity measurements that are taken phase-locked to the commanded actuation waveform. The time scales associated with the actuation process is determined from PIV measurements of vorticity flux downstream of the trailing edge. Circulation time history shows that the entire flow over the airfoil readjusts within about 1.5 TCONV, which is about two orders of magnitude shorter than the characteristic time associated with the controlled maneuver of the wind tunnel model. This illustrates that flow-control actuation can be typically effected on time scales commensurate with the flow's convective time scale, and that the maneuver response is only limited by the inertia of the platform. Supported by AFSOR.

  15. Comparable Cerebral Oxygenation Patterns in Younger and Older Adults during Dual-Task Walking with Increasing Load

    PubMed Central

    Fraser, Sarah A.; Dupuy, Olivier; Pouliot, Philippe; Lesage, Frédéric; Bherer, Louis

    2016-01-01

    The neuroimaging literature on dual-task gait clearly demonstrates increased prefrontal cortex (PFC) involvement when performing a cognitive task while walking. However, findings from direct comparisons of the cerebral oxygenation patterns of younger (YA) and older (OA) adults during dual-task walking are mixed and it is unclear how YA and OA respond to increasing cognitive load (difficulty) while walking. This functional near infra-red (fNIRS) study examined cerebral oxygenation of YA and OA during self-paced dual-task treadmill walking at two different levels of cognitive load (auditory n-back). Changes in accuracy (%) as well as oxygenated (HbO) and deoxygenated (HbR) hemoglobin were examined. For the HbO and HbR measures, eight regions of interest (ROIs) were assessed: the anterior and posterior dorsolateral and ventrolateral PFC (aDLPFC, pDLPFC, aVLPFC, pVLPFC) in each hemisphere. Nineteen YA (M = 21.83 years) and 14 OA (M = 66.85 years) walked at a self-selected pace while performing auditory 1-back and 2-back tasks. Walking alone (single motor: SM) and performing the cognitive tasks alone (single cognitive: SC) were compared to dual-task walking (DT = SM + SC). In the behavioural data, participants were more accurate in the lowest level of load (1-back) compared to the highest (2-back; p < 0.001). YA were more accurate than OA overall (p = 0.009), and particularly in the 2-back task (p = 0.048). In the fNIRS data, both younger and older adults had task effects (SM < DT) in specific ROIs for ΔHbO (three YA, one OA) and ΔHbR (seven YA, eight OA). After controlling for walk speed differences, direct comparisons between YA and OA did not reveal significant age differences, but did reveal a difficulty effect in HbO in the left aDLPFC (p = 0.028) and significant task effects (SM < DT) in HbR for six of the eight ROIs. Findings suggest that YA and OA respond similarly to manipulations of cognitive load when walking on a treadmill at a self-selected pace. PMID

  16. Cadmium increases ferroportin-1 gene expression in J774 macrophage cells via the production of reactive oxygen species.

    PubMed

    Park, Bo-Yeon; Chung, Jayong

    2009-01-01

    Cadmium intoxication has been associated with the dysregulation of iron homeostasis. In the present study, we investigated the effect of cadmium on the expression of ferroportin 1 (FPN1), an important iron transporter protein that is involved in iron release from macrophages. When we incubated cadmium with J774 mouse macrophage cells, FPN1 mRNA levels were significantly increased in a dose- and time-dependent manner. Furthermore, the cadmium-induced FPN1 mRNA expression was associated with increased levels of FPN1 protein. On the other hand, cadmium-mediated FPN1 mRNA induction in J774 cells was completely blocked when cells were co-treated with a transcription inhibitor, acitomycin D. Also, cadmium directly stimulated the activity of the FPN1-promoter driven luciferase reporter, suggesting that the cadmium up-regulates FPN1 gene expression in a transcription-dependent manner. Finally, cadmium exposure to J774 macrophages increased intracellular reactive oxygen species (ROS) levels by ~ 2-fold, compared to untreated controls. When J774 cells were co-treated with antioxidant N-acetylcystein, the cadmium-induced FPN1 mRNA induction was significantly attenuated. In summary, the results of this study clearly demonstrated that cadmium increased FPN1 expression in macrophages through a mechanism that involves ROS production, and suggests another important interaction between iron and cadmium metabolism. PMID:20090884

  17. Is soccer kick performance better after a "faking" (cutting) maneuver task?

    PubMed

    Katis, Athanasios; Kellis, Eleftherios

    2011-03-01

    Cutting in soccer is a common skill used to avoid the opponent's pressure but the potential effects of such a skill on instep kicking performance have not been previously investigated. The purpose of this study was to examine the differences in lower limb biomechanics between straight approach soccer kicks and kicks performed following a cutting maneuver task. Ten young amateur soccer players performed, in a random order, instep kicks after a two-step straight approach run and kicks after a double "faking" cutting maneuver task. The results showed that kicking after a cutting maneuver task displayed significantly lower ball speed values compared with the straight approach instep kicking (16.73 vs. 19.78 m/s, respectively; p < 0.05). Moreover, analysis of variance showed significant differences between the two kicking conditions in ankle, knee and hip joint displacements. The present study indicated that performing instep kicks after a double-cutting maneuver reduces ball and foot speed probably due to increasing joint frontal and transverse plane rotations. Improvements in the performance of the cutting maneuver task through training might result in better transfer of energy and speed to the kicking task thus permitting players to perform more powerful kicks under realistic game conditions. PMID:21560750

  18. The effectiveness of the head-turn-plus-chin-down maneuver for eliminating vallecular residue.

    PubMed

    Nagy, Ahmed; Peladeau-Pigeon, Melanie; Valenzano, Teresa Josephine; Namasivayam, Ashwini Marini; Steele, Catriona Margaret

    2016-04-01

    Purpose When swallowing efficiency is impaired, residue accumulates in the pharynx. Cued or spontaneous swallows in the head neutral position do not always successfully clear residue. We investigated the impact of a novel maneuver on residue clearance by combining a head turn with the chin down posture. Methods Data were collected from 26 participants who demonstrated persistent vallecular residue after an initial head neutral clearance swallow in videofluoroscopy. Participants were cued to perform a head-turn-plus-chin-down swallow, with the direction of head turn randomized. Pixel-based measures of residue in the vallecular space before and after the maneuver were made on still frame lateral images using ImageJ software. Measures of % full and the Normalized Residue Ratio Scale (NRRS) were extracted. Univariate analyses of variance were used to detect significant reductions in residue. Results On average, pre-maneuver measures showed residue filling 56-73% of the valleculae, depending on stimulus consistency (NRRS scores: 0.2-0.4). More than 80% of pre-swallow measures displayed NRRS ratios > 0.06, a threshold previously linked to increased risk of post-swallow aspiration. Conclusion The head-turn-plus-chin-down maneuver achieved significant reductions in residue for thin and nectar-thick fluids, suggesting that this maneuver can be effective in reducing persistent vallecular residue with these consistencies. PMID:27191873

  19. Acrolein-Induced Increases in Blood Pressure and Heart Rate Are Coupled with Decreased Blood Oxygen Levels During Exposure in Hypertensive Rats

    EPA Science Inventory

    Exposure to air pollution increases the risk of cardiovascular morbidity and mortality, especially in individuals with pre-existing cardiovascular disease. Recent studies link exposure to air pollution with reduced blood oxygen saturation suggesting that hypoxia is a potential me...

  20. Haematological rather than skeletal muscle adaptations contribute to the increase in peak oxygen uptake induced by moderate endurance training.

    PubMed

    Montero, David; Cathomen, Adrian; Jacobs, Robert A; Flück, Daniela; de Leur, Jeroen; Keiser, Stefanie; Bonne, Thomas; Kirk, Niels; Lundby, Anne-Kristine; Lundby, Carsten

    2015-10-15

    It remains unclear whether improvements in peak oxygen uptake (V̇(O2peak)) following endurance training (ET) are primarily determined by central and/or peripheral adaptations. Herein, we tested the hypothesis that the improvement in V̇(O2peak) following 6 weeks of ET is mainly determined by haematological rather than skeletal muscle adaptations. Sixteen untrained healthy male volunteers (age = 25 ± 4 years, V̇(O2peak) = 3.5 ± 0.5 l min(-1)) underwent supervised ET (6 weeks, 3-4 sessions per week). V̇(O2peak), peak cardiac output (Q̇(peak)), haemoglobin mass (Hb(mass)) and blood volumes were assessed prior to and following ET. Skeletal muscle biopsies were analysed for mitochondrial volume density (Mito(VD)), capillarity, fibre types and respiratory capacity (OXPHOS). After the post-ET assessment, red blood cell volume (RBCV) was re-established at the pre-ET level by phlebotomy and V̇(O2peak) and Q̇(peak) were measured again. We speculated that the contribution of skeletal muscle adaptations to the ET-induced increase in V̇(O2peak) would be revealed when controlling for haematological adaptations. V̇(O2peak) and Q̇(peak) were increased (P < 0.05) following ET (9 ± 8 and 7 ± 6%, respectively) and decreased (P < 0.05) after phlebotomy (-7 ± 7 and -10 ± 7%). RBCV, plasma volume and Hb(mass) all increased (P < 0.05) after ET (8 ± 4, 4 ± 6 and 6 ± 5%). As for skeletal muscle adaptations, capillary-to-fibre ratio and total Mito(VD) increased (P < 0.05) following ET (18 ± 16 and 43 ± 30%), but OXPHOS remained unaltered. Through stepwise multiple regression analysis, Q̇(peak), RBCV and Hb(mass) were found to be independent predictors of V̇(O2peak). In conclusion, the improvement in V̇(O2peak) following 6 weeks of ET is primarily attributed to increases in Q̇(peak) and oxygen-carrying capacity of blood in untrained healthy young subjects. PMID:26282186

  1. Increasing mean arterial pressure in cardiogenic shock secondary to myocardial infarction: effects on hemodynamics and tissue oxygenation.

    PubMed

    Perez, Pierre; Kimmoun, Antoine; Blime, Vincent; Levy, Bruno

    2014-04-01

    There are very few data regarding the effects of norepinephrine uptitration on global and regional hemodynamics in cardiogenic shock. We studied 25 patients with shock secondary to myocardial infarction successfully treated with percutaneous coronary intervention. Before the inclusion, 16 of 25 patients presented a cardiac arrest in the presence of medical staff. Norepinephrine was titrated to increase mean arterial pressure (MAP) from 65 to 85 mmHg during 1 h. Swan-Ganz variables, arterial and mixed venous blood gases, lactate, and thenar near-infrared spectroscopy variables (muscle tissue oxygen saturation [StO2] and its changes during a vascular occlusion test) were measured before, 1 h after norepinephrine uptitration, and 1 h after norepinephrine downtitration. To obtain a MAP at 85 mmHg, norepinephrine was increased from 0.6 (0.28-1.2) to 1.53 µg · kg · min (0.76-2.6 µg · kg · min) (P < 0.00001) (median and interquartile range), with no change in heart rate. Norepinephrine uptitration significantly increased cardiac index (2.3 ± 0.5 to 2.8 ± 0.1 L · min · m), cardiac power index (0.40 ± 0.1 to 0.55 ± 0.1 W/m), mixed venous oxygen saturation (69% ± 9% to 73% ± 9%), and coronary perfusion pressure (32 ± 3 to 43 ± 4 mmHg). Lactate level decreased from 2.6 ± 1.7 to 1.6 ± 0.4 mmol/L (P < 0.05). Pulmonary artery occlusion pressure remained unchanged. Regarding near-infrared spectroscopy variables, all values except StO2 were significantly pathological when compared with healthy volunteers. The StO2 recovery slope and delta StO2, respectively, increased from 3.0% ± 1.3%/s to 3.6% ± 1.3%/s and 10% ± 3% to 14% ± 4%, whereas StO2 did not change (83% ± 6% to 83% ± 7%). After H1, norepinephrine was decreased to basal values, and all variables returned to baseline. In conclusion, a short-term increase in MAP with norepinephrine in resuscitated cardiogenic shock complicated by postreperfusion disease is associated with better cardiac performance and

  2. Arsenite induces endothelial cell permeability increase through a reactive oxygen species-vascular endothelial growth factor pathway.

    PubMed

    Bao, Lingzhi; Shi, Honglian

    2010-11-15

    As a potent environmental oxidative stressor, arsenic exposure has been reported to exacerbate cardiovascular diseases and increase vascular endothelial cell monolayer permeability. However, the underlying mechanism of this effect is not well understood. In this paper, we test our hypothesis that reactive oxygen species (ROS)-induced vascular endothelial growth factor (VEGF) expression may play an important role in an arsenic-caused increase of endothelial cell monolayer permeability. The mouse brain vascular endothelial cell bEnd3 monolayer was exposed to arsenite for 1, 3, and 6 days. The monolayer permeability, VEGF protein release, and ROS generation were determined. In addition, VE-cadherin and zonula occludens-1 (ZO-1), two membrane structure proteins, were immunostained to elucidate the effects of arsenite on the cell-cell junction. The roles of ROS and VEGF in arsenite-induced permeability was determined by inhibiting ROS with antioxidants and immuno-depleting VEGF with a VEGF antibody. We observed that arsenite increased bEnd3 monolayer permeability, elevated the production of cellular ROS, and increased VEGF release. VE-cadherin and ZO-1 disruptions were also found in cells treated with arsenite. Furthermore, both antioxidant (N-acetyl cysteine and tempol) and the VEGF antibody treatments significantly lowered the arsenite-induced permeability of the bEnd3 monolayer as well as VEGF expression. VE-cadherin and ZO-1 disruptions were also diminished by N-acetyl cysteine and the VEGF antibody. Our data suggest that the increase in VEGF expression caused by ROS may play an important role in the arsenite-induced increase in endothelial cell permeability.

  3. Arsenite induces endothelial cell permeability increase through a reactive oxygen species-vascular endothelial growth factor pathway.

    PubMed

    Bao, Lingzhi; Shi, Honglian

    2010-11-15

    As a potent environmental oxidative stressor, arsenic exposure has been reported to exacerbate cardiovascular diseases and increase vascular endothelial cell monolayer permeability. However, the underlying mechanism of this effect is not well understood. In this paper, we test our hypothesis that reactive oxygen species (ROS)-induced vascular endothelial growth factor (VEGF) expression may play an important role in an arsenic-caused increase of endothelial cell monolayer permeability. The mouse brain vascular endothelial cell bEnd3 monolayer was exposed to arsenite for 1, 3, and 6 days. The monolayer permeability, VEGF protein release, and ROS generation were determined. In addition, VE-cadherin and zonula occludens-1 (ZO-1), two membrane structure proteins, were immunostained to elucidate the effects of arsenite on the cell-cell junction. The roles of ROS and VEGF in arsenite-induced permeability was determined by inhibiting ROS with antioxidants and immuno-depleting VEGF with a VEGF antibody. We observed that arsenite increased bEnd3 monolayer permeability, elevated the production of cellular ROS, and increased VEGF release. VE-cadherin and ZO-1 disruptions were also found in cells treated with arsenite. Furthermore, both antioxidant (N-acetyl cysteine and tempol) and the VEGF antibody treatments significantly lowered the arsenite-induced permeability of the bEnd3 monolayer as well as VEGF expression. VE-cadherin and ZO-1 disruptions were also diminished by N-acetyl cysteine and the VEGF antibody. Our data suggest that the increase in VEGF expression caused by ROS may play an important role in the arsenite-induced increase in endothelial cell permeability. PMID:20954712

  4. [Cardiovascular consequences of aerobic maneuvers].

    PubMed

    Trivelloni, Pierandrea; Berrettini, Umberto

    2010-10-01

    Gravitational (G) stress during aerobatics flights, both military and civilian, can suddenly incapacitate pilots in agile and supermaneuverable aircrafts. High +Gz stress, up to +9Gz, has two different physiological consequences: the first is the drop in head-level blood pressure that is proportional to the G load; the other, slightly delayed, is the blood pooling in the lower part of the body and the abdomen. This blood shift results in a decreased return of venous blood to the heart, decreased cardiac output, and decreased blood pressure, leading to a likely loss of consciousness. The natural countermeasure against the effects of high G stress is the baroreceptor reflex. The human physiological tolerance to the gravito-inertial forces developed in flight operations can be increased by physiological and technological means.

  5. Effects of exposure time during flight maneuvers on passenger subjective comfort rating

    NASA Technical Reports Server (NTRS)

    Brown, V. J.

    1975-01-01

    The effects were investigated of length of exposure time to a flight maneuver environment on subjective passenger evaluation of ride comfort. Four statistical analysis tests were performed on ride comfort ratings obtained during one two-hour test flight wherein eleven test subjects were exposed to two identical programmed sequences of twenty four flight segments which covered a wide range of maneuver conditions. The results of the analysis indicate that, for over ninety five percent of the segments, there is no significant change in the test subjects comfort ratings of identical segments spaced one hour apart. These results are in contrast to those found in previous studies involving a vibration environment, rather than flight maneuver environment, where increased exposure-time was found to cause a degradation of ride comfort ratings.

  6. Trial maneuver generation and selection in the Paladin tactical decision generation system

    NASA Technical Reports Server (NTRS)

    Chappell, Alan R.; Mcmanus, John W.; Goodrich, Kenneth H.

    1993-01-01

    To date, increased levels of maneuverability and controllability in aircraft have been postulated as tactically advantageous, but little research has studied maneuvers or tactics that make use of these capabilities. In order to help fill this void, a real-time tactical decision generation system for air combat engagements, Paladin, has been developed. Paladin models an air combat engagement as a series of discrete decisions. A detailed description of Paladin's decision making process is presented. This includes the sources of data used, methods of generating reasonable maneuvers for the Paladin aircraft, and selection criteria for choosing the 'best' maneuver. Simulation results are presented that show Paladin to be relatively insensitive to errors introduced into the decision process by estimation of future positional and geometric data.

  7. Trial Maneuver Generation and Selection in the Paladin Tactical Decision Generation System

    NASA Technical Reports Server (NTRS)

    Chappell, Alan R.; McManus, John W.; Goodrich, Kenneth H.

    1992-01-01

    To date, increased levels of maneuverability and controllability in aircraft have been postulated as tactically advantageous, but little research has studied maneuvers or tactics that make use of these capabilities. In order to help fill this void, a real time tactical decision generation system for air combat engagements, Paladin, has been developed. Paladin models an air combat engagement as a series of discrete decisions. A detailed description of Paladin's decision making process is presented. This includes the sources of data used, methods of generating reasonable maneuvers for the Paladin aircraft, and selection criteria for choosing the "best" maneuver. Simulation results are presented that show Paladin to be relatively insensitive to errors introduced into the decision process by estimation of future positional and geometric data.

  8. Improvement of the redox balance increases L-valine production by Corynebacterium glutamicum under oxygen deprivation conditions.

    PubMed

    Hasegawa, Satoshi; Uematsu, Kimio; Natsuma, Yumi; Suda, Masako; Hiraga, Kazumi; Jojima, Toru; Inui, Masayuki; Yukawa, Hideaki

    2012-02-01

    Production of L-valine under oxygen deprivation conditions by Corynebacterium glutamicum lacking the lactate dehydrogenase gene ldhA and overexpressing the L-valine biosynthesis genes ilvBNCDE was repressed. This was attributed to imbalanced cofactor production and consumption in the overall L-valine synthesis pathway: two moles of NADH was generated and two moles of NADPH was consumed per mole of L-valine produced from one mole of glucose. In order to solve this cofactor imbalance, the coenzyme requirement for L-valine synthesis was converted from NADPH to NADH via modification of acetohydroxy acid isomeroreductase encoded by ilvC and introduction of Lysinibacillus sphaericus leucine dehydrogenase in place of endogenous transaminase B, encoded by ilvE. The intracellular NADH/NAD(+) ratio significantly decreased, and glucose consumption and L-valine production drastically improved. Moreover, L-valine yield increased and succinate formation decreased concomitantly with the decreased intracellular redox state. These observations suggest that the intracellular NADH/NAD(+) ratio, i.e., reoxidation of NADH, is the primary rate-limiting factor for L-valine production under oxygen deprivation conditions. The L-valine productivity and yield were even better and by-products derived from pyruvate further decreased as a result of a feedback resistance-inducing mutation in the acetohydroxy acid synthase encoded by ilvBN. The resultant strain produced 1,470 mM L-valine after 24 h with a yield of 0.63 mol mol of glucose(-1), and the L-valine productivity reached 1,940 mM after 48 h.

  9. An oxygenated metabolite of benzo[a]pyrene increases hepatic β-oxidation of fatty acids in chick embryos.

    PubMed

    Westman, Ola; Larsson, Maria; Venizelos, Nikolaos; Hollert, Henner; Engwall, Magnus

    2014-05-01

    Polycyclic aromatic hydrocarbons (PAHs) are well-known carcinogens to humans and ecotoxicological effects have been shown in several studies. However, PAHs can also be oxidized into more water soluble-oxygenated metabolites (Oxy-PAHs). The first purpose of the present project was to (1) assess the effects of a mixture containing three parent PAHs: anthracene, benz[a]anthracene, and benzo[a]pyrene versus a mixture of their oxygenated metabolites, namely: anthracene-9,10-dione, benz[a]anthracene-7,12-dione, and 9,10-dihydrobenzo[a]pyrene-7-(8H)-one on the hepatic fatty acid β-oxidation in chicken embryos (Gallus gallus domesticus) exposed in ovo. The second and also main purpose of the project was to (2) assess the effects of the parent PAHs versus their oxy-PAHs analogues when injected individually, followed by (3) additional testing of the individual oxy-PAHs. The hepatic β-oxidation was measured using a tritium release assay with [9,10-(3)H]-palmitic acid (16:0) as substrate. The result from the first part (1) showed reduced hepatic β-oxidation after exposure in ovo to a mixture of three PAHs, however, increased after exposure to the mixture of three oxy-PAHs compared to control. The result from the second part (2) and also the follow-up experiment (3) showed that 9,10-dihydrobenzo[a]pyrene-7-(8H)-one was the causative oxy-PAH. The implication of this finding on the risk assessment of PAH metabolite exposure in avian wildlife remains to be determined. To the best of our knowledge, no similar studies have been reported.

  10. Evaluation of the Safe Ischemic Time of Clamping During Intermittent Pringles Maneuver in Rabbits

    PubMed Central

    Kolahdoozan, Mohsen; Behdad, Akbar; Hosseinpour, Mehrdad; Behdad, Samin; Rezaei, Mohammad Taghi

    2015-01-01

    Background: The liver is the most commonly injured organ in blunt abdominal trauma. Although major hepatic bleeding may be partially controlled with portal triade clamping (the Pringle’s maneuver), continuous prolonged clamping results in liver ischemia. Objectives: The purpose of this study was to determine the safe time of Pringle maneuver based on pathologic changes of liver in rabbit models. Materials and Methods: In an experimental study, 20 New-Zealand white rabbits were selected. In laparotomy, a blunt dissector was passed through the foramen of Winslow and the hepato-duodenal ligament encircled with an umbilical tape. En masse Pringle maneuver was performed using atraumatic flexible clamps. Rabbits were divided into four groups based on Pringle maneuver time (30 minutes, 45 minutes, 60 minutes, and 75 minutes). A hepatic biopsy was performed at the beginning of operation. The degree of tissue injury was evaluated using blood markers. Results: There were five rabbits in each group. At the end of 60 minutes ischemia, only minor alterations were observed in pathological specimens. At the end of 75 minutes, hepatocyte damage and necrosis were observed. The serum levels of alanine aminotransferase (Group A: P = 0.02; Group B: P = 0.01; Group C: P = 0.0002; Group D: P = 0.01) and Aspartate aminotransferase (Group A: P = 0.03; Group B: P = 0.002; Group C: P = 0.0004; Group D: P = 0.0003) were significantly increased post-operatively. The maximum level was in the first day after operation. Conclusions: Continuous portal triade clamping (the Pringle maneuver) during liver ischemia (30 and 45 minutes) in rabbits resulted in no ischemic change. Increasing time of clamping to 30 minutes was safe in intermittent Pringle maneuver. PMID:26848477

  11. Compost as a soil supplement increases the level of antioxidant compounds and oxygen radical absorbance capacity in strawberries.

    PubMed

    Wang, Shiow Y; Lin, Hsin-Shan

    2003-11-01

    Compost as a soil supplement significantly enhanced levels of ascorbic acid (AsA) and glutathione (GSH) and ratios of AsA/dehydroascorbic acid (DHAsA) and GSH/oxidized glutathione (GSSG) in fruit of two strawberry (Fragaria x ananassa Duch.) cultivars, Allstar and Honeoye. The peroxyl radical (ROO(*)) as well as the superoxide radical (O(2)(*)(-)), hydrogen peroxide (H(2)O(2)), hydroxyl radical (OH(*)), and singlet oxygen ((1)O(2)) absorbance capacity in strawberries increased significantly with increasing fertilizer strength and compost use. The planting medium (compost) x fertilizer interaction for phenolics and flavonoids was significant. Fruit from plants grown in full-strength fertilizer with 50% soil plus 50% compost and 100% compost yielded fruit with the highest levels of phenolics, flavonol, and anthocyanin content. A positive relationship between antioxidant activities and contents of AsA and GSH and ratios of AsA/DHAsA and GSH/GSSG existed in fruit of both strawberry cultivars. Correlation coefficients for the content of antioxidant components versus antioxidant activity [against ROO(*), O(2)(*)(-), H(2)O(2), OH(*), or (1)O(2)] ranged from r( )()= 0.7706 for H(2)O(2) versus GSH/GSSH in cv. Allstar to r = 0.9832 for O(2)(*)(-) versus total flavonoids in cv. Allstar.

  12. GGsTOP increases migration of human periodontal ligament cells in vitro via reactive oxygen species pathway

    PubMed Central

    JIANG, YING; WANG, XIANG; LI, YING; MU, SEN; ZHOU, SHUANG; LIU, YI; ZHANG, BIN

    2016-01-01

    GGsTOP is a novel and selective inhibitor of gamma-glutamyl transferase (GGT), a cell-surface enzyme that has a key role in glutathione homeostasis and the maintenance of cellular reactive oxygen species (ROS). ROS are essential for wound healing. However, little is known about the molecular mechanisms underlying the inhibition of GGT by GGsTOP in human periodontal ligament cells (hPLCs). The present study assessed GGT expression in mouse periodontal ligament tissues, GGT activity in hPLCs, and the potential physiological effect of GGsTOP on hPLC migration. Immunohistochemical analysis confirmed that GGT was widely expressed in mouse periodontal ligament tissue. Treatment with GGsTOP was associated with greater proliferation and migration of hPLCs, and higher levels of cellular ROS compared with untreated hPLCs. However, the increase in intracellular ROS was attenuated in hPLCs co-cultured with the anti-oxidant N-acetylcysteine (NAC), a precursor of glutathione. The higher ROS levels associated with GGsTOP treatment were in parallel with increases in the levels of type I collagen and alpha smooth muscle actin, which was inhibited in hPLCs co-cultured with NAC. Thus, GGsTOP may promote hPLC migration and participate in the maintenance of the periodontal ligament apparatus via the ROS pathway. PMID:27035100

  13. Commercial sport drinks versus light meal combat rations: effect on simulated combat maneuvers.

    PubMed

    Bell, Douglas G; McLellan, Tom M; Boyne, Stephen

    2002-08-01

    This study compared a light meal combat ration (LMCR) to specific commercial sport drinks (CSD) and the effect of their ingestion on time to exhaustion during simulated combat maneuvers (SCM). The SCM consisted of three activities: a 2-hour march at 50% of maximal aerobic capacity (VO2max); a subsequent 1-hour run at 70% VO2max; and a run to exhaustion at 80% VO2max. During SCM, the subjects consumed one of four different meals: three CSD (Ergo, Go Sports, and Gatorlode), and the LMCR. In addition, one SCM was conducted with half-rations. Oxygen consumption, heart rate, and rating of perceived exertion were evaluated during each phase of the SCM. Time in minutes (mean +/- SD) to exhaustion at 80% VO2max for Ergo (42.3 +/- 8.9), Go Sports (39.4 +/- 13.3), and Gatorlode (37.7 +/- 8.6) was not significantly different from that for LMCR (36.4 +/- 13.0) but was greater than that for half-LMCR (30.3 +/- 9.3). O2 consumption, heart rate, and rating of perceived exertion were not affected by meal type but did increase over time for each stage of the SCM. We conclude that the amount of calories ingested was responsible for the differences noted in time to exhaustion. We further conclude that the CSD represent a readily available source of energy and fluid that could be used to replace and/or supplement the current LMCR.

  14. NADPH Oxidase-derived Reactive Oxygen Species Increases Expression of Monocyte Chemotactic Factor Genes in Cultured Adipocytes*

    PubMed Central

    Han, Chang Yeop; Umemoto, Tomio; Omer, Mohamed; Den Hartigh, Laura J.; Chiba, Tsuyoshi; LeBoeuf, Renee; Buller, Carolyn L.; Sweet, Ian R.; Pennathur, Subramaniam; Abel, E. Dale; Chait, Alan

    2012-01-01

    Excess glucose and free fatty acids delivered to adipose tissue causes local inflammation, which contributes to insulin resistance. Glucose and palmitate generate reactive oxygen species (ROS) in adipocytes, leading to monocyte chemotactic factor gene expression. Docosahexaenoate (DHA) has the opposite effect. In this study, we evaluated the potential sources of ROS in the presence of excess nutrients. Differentiated 3T3-L1 adipocytes were exposed to palmitate and DHA (250 μm) in either 5 or 25 mm glucose to evaluate the relative roles of mitochondrial electron transport and NADPH oxidases (NOX) as sources of ROS. Excess glucose and palmitate did not increase mitochondrial oxidative phosphorylation. However, glucose exposure increased glycolysis. Of the NOX family members, only NOX4 was expressed in adipocytes. Moreover, its activity was increased by excess glucose and palmitate and decreased by DHA. Silencing NOX4 inhibited palmitate- and glucose-stimulated ROS generation and monocyte chemotactic factor gene expression. NADPH, a substrate for NOX, and pentose phosphate pathway activity increased with glucose but not palmitate and decreased with DHA exposure. Inhibition of the pentose phosphate pathway by glucose-6-phosphate dehydrogenase inhibitors and siRNA suppressed ROS generation and monocyte chemotactic factor gene expression induced by both glucose and palmitate. Finally, both high glucose and palmitate induced NOX4 translocation into lipid rafts, effects that were blocked by DHA. Excess glucose and palmitate generate ROS via NOX4 rather than by mitochondrial oxidation in cultured adipocytes. NOX4 is regulated by both NADPH generated in the PPP and translocation of NOX4 into lipid rafts, leading to expression of monocyte chemotactic factors. PMID:22287546

  15. Increased viscosity of hemoglobin-based oxygen carriers retards NO-binding when perfused through narrow gas-permeable tubes.

    PubMed

    Sakai, Hiromi; Okuda, Naoto; Takeoka, Shinji; Tsuchida, Eishun

    2011-03-01

    Increased fluid viscosity of a solution of hemoglobin-based oxygen carriers (HBOCs) reduces vasoconstrictive effects because increased shear stress on the vascular wall enhances the production of vasorelaxation factors such as NO. Nevertheless, on a microcirculatory level, it remains unclear how viscosity affects the reaction of HBOCs and NO. In this study, different HBOCs were perfused through narrow gas-permeable tubes (25 μm inner diameter at 1 mm/s centerline velocity; hemoglobin concentration [Hb]=5 g/dL). The reaction was examined microscopically based on the Hb visible-light absorption spectrum. When immersed in a NO atmosphere, the NO-binding of deoxygenated Hb solution (viscosity, 1.1 cP at 1000 s(-1)) in the tube occurred about twice as rapidly as that of red blood cells (RBCs): 1.6 cP. Binding was reduced by PEGylation (PEG-Hb, 7.7 cP), by addition of a high molecular weight hydroxyethyl starch (HES) (2.8 cP), and by encapsulation to form Hb-vesicles (HbVs, 1.5 cP; particle size 279 nm). However, the reduction was not as great as that shown for RBCs. A mixture of HbVs and HES (6.2 cP) showed almost identical NO-binding to that of RBCs. Higher viscosity and particle size might reduce lateral diffusion when particles are flowing. The HbVs with HES showed the slowest NO-binding. Furthermore, Hb encapsulation and PEGylation, but not HES-addition, tended to retard CO-binding. Increased viscosity reportedly enhances production of endothelium NO. In addition, our results show that the increased viscosity also inhibits the reaction with NO. Each effect might mitigate vasoconstriction.

  16. Venous return curves obtained from graded series of valsalva maneuvers

    NASA Technical Reports Server (NTRS)

    Mastenbrook, S. M., Jr.

    1974-01-01

    The effects were studied of a graded series of valsalva-like maneuvers on the venous return, which was measured transcutaneously in the jugular vein of an anesthetized dog, with the animal serving as its own control. At each of five different levels of central venous pressure, the airway pressure which just stopped venous return during each series of maneuvers was determined. It was found that this end-point airway pressure is not a good estimator of the animal's resting central venous pressure prior to the simulated valsalva maneuver. It was further found that the measured change in right atrial pressure during a valsalva maneuver is less than the change in airway pressure during the same maneuver, instead of being equal, as had been expected. Relative venous return curves were constructed from the data obtained during the graded series of valsalva maneuvers.

  17. Slew maneuvers of Spacecraft Control Laboratory Experiment (SCOLE)

    NASA Technical Reports Server (NTRS)

    Kakad, Yogendra P.

    1992-01-01

    This is the final report on the dynamics and control of slew maneuvers of the Spacecraft Control Laboratory Experiment (SCOLE) test facility. The report documents the basic dynamical equation derivations for an arbitrary large angle slew maneuver as well as the basic decentralized slew maneuver control algorithm. The set of dynamical equations incorporate rigid body slew maneuver and three dimensional vibrations of the complete assembly comprising the rigid shuttle, the flexible beam, and the reflector with an offset mass. The analysis also includes kinematic nonlinearities of the entire assembly during the maneuver and the dynamics of the interactions between the rigid shuttle and the flexible appendage. The equations are simplified and evaluated numerically to include the first ten flexible modes to yield a model for designing control systems to perform slew maneuvers. The control problem incorporates the nonlinear dynamical equations and is expressed in terms of a two point boundary value problem.

  18. Replacing the Transfusion of 1–2 Units of Blood with Plasma Expanders that Increase Oxygen Delivery Capacity: Evidence from Experimental Studies

    PubMed Central

    Tsai, Amy G.; Salazar Vázquez, Beatriz Y.; Cabrales, Pedro; Kistler, Erik B.; Tartakovsky, Daniel M.; Subramaniam, Shankar; Acharya, Seetharama A.; Intaglietta, Marcos

    2014-01-01

    At least a third of the blood supply in the world is used to transfuse 1–2 units of packed red blood cells for each intervention and most clinical trials of blood substitutes have been carried out at this level of oxygen carrying capacity (OCC) restoration. However, the increase of oxygenation achieved is marginal or none at all for molecular hemoglobin (Hb) products, due to their lingering vasoactivity. This has provided the impetus for the development of “oxygen therapeutics” using Hb-based molecules that have high oxygen affinity and target delivery of oxygen to anoxic areas. However it is still unclear how these oxygen carriers counteract or mitigate the functional effects of anemia due to obstruction, vasoconstriction and under-perfusion. Indeed, they are administered as a low dosage/low volume therapeutic Hb (subsequently further diluted in the circulatory pool) and hence induce extremely small OCC changes. Hyperviscous plasma expanders provide an alternative to oxygen therapeutics by increasing the oxygen delivery capacity (ODC); in anemia they induce supra-perfusion and increase tissue perfusion (flow) by as much as 50%. Polyethylene glycol conjugate albumin (PEG-Alb) accomplishes this by enhancing the shear thinning behavior of diluted blood, which increases microvascular endothelial shear stress, causes vasodilation and lowering peripheral vascular resistance thus facilitating cardiac function. Induction of supra-perfusion takes advantage of the fact that ODC is the product of OCC and blood flow and hence can be maintained by increasing either or both. Animal studies suggest that this approach may save a considerable fraction of the blood supply. It has an additional benefit of enhancing tissue clearance of toxic metabolites. PMID:25350267

  19. Anterior Displacement of Lamina Cribrosa during Valsalva Maneuver in Young Healthy Eyes

    PubMed Central

    Kim, Yong Woo; Girard, Michael J. A.; Mari, Jean Martial; Jeoung, Jin Wook

    2016-01-01

    Purpose To investigate lamina cribrosa (LC) displacement during the Valsalva maneuver in young healthy eyes using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT). Methods Forty-eight eyes of 48 young healthy volunteers (age range: 20–34 years) underwent intraocular pressure (IOP) measurement by Goldmann applanation tonometry as well as Cirrus HD-OCT scans before and during the Valsalva maneuver. The optic nerve head (ONH) parameters (average retinal nerve fiber layer thickness, rim area, disc area, average C/D ratio, vertical C/D ratio, cup volume), anterior LC depth (LCD), subfoveal and peripapillary choroidal thickness, and neural canal opening diameter were measured on compensated OCT and compared during Valsalva challenge. The subjects were asked to take a five-minute break after each Valsalva maneuver. Results During the Valsalva maneuver, the IOP significantly increased, from 12.7 ± 3.0 mmHg to 16.0 ± 3.2 mmHg (P < 0.001), while the LCD sharply decreased, from 463.4 ± 118.8 μm to 427.3 ± 106.4 μm (P < 0.001). The subfoveal choroidal thickness (300.7 ± 90.6 vs. 309.6 ± 93.5 μm), peripapilllary choroidal thickness (152.2 ± 55.4 vs. 150.8 ± 49.3 μm), neural canal opening diameter (1651.8 ± 204.2 vs. 1651.0 ± 217.6 μm), and all of the ONH parameters did not change significantly (all P > 0.05). Conclusions The Valsalva maneuver induced anterior displacement of the LC, but did not alter the choroidal thickness or ONH morphology. The data describe the positional characteristics of the LC in response to the Valsalva maneuver in young healthy eyes. PMID:27442120

  20. Fugitive dust emissions from off-road vehicle maneuvers on military training lands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Off-road vehicle training can contribute to air quality degradation because of increased wind erosion as a result of soil disruption during high wind events. However, limited information exists regarding the impacts of off-road vehicle maneuvering on wind erosion potential of soils. This study was c...

  1. Hesperetin induces apoptosis of esophageal cancer cells via mitochondrial pathway mediated by the increased intracellular reactive oxygen species.

    PubMed

    Wu, Dandan; Zhang, Jixiang; Wang, Jing; Li, Jiao; Liao, Fei; Dong, Weiguo

    2016-03-01

    Esophageal cancer is of high prevalence and poor prognosis. Hesperetin has been reported to exert antitumor ability by inducing apoptosis in many cancers in vitro and in vivo without obvious toxicity. However, there is no study concerning about the effect of hesperetin on esophageal cancer. In this study, we aimed to investigate whether hesperetin could induce apoptosis in esophageal cancer cells and explore its potential mechanism. We found that hesperetin induced esophageal cancer cells apoptosis in a concentration-dependent and time-dependent manner compared with the untreated cells. Hoechst 33258 staining and flow cytometry analysis showed more apoptotic cells in the hesperetin-treated group (p < 0.05, respectively). The intracellular reactive oxygen species (ROS) increased significantly, and glutathione (GSH) was depleted. The loss of △Ψ m was more tremendous in the hesperetin-treated cells. N-acetylcysteine (NAC) reduced the proapoptotic ability of hesperetin, while DL-buthionine-S, R-sulfoximine (BSO) enhanced the anticancer effect. Western blotting showed that the expression levels of cytochrome C (Cyt C) and apoptosis-inducing factor (AIF) decreased in mitochondria and increased in cytoplasm (p < 0.05). The levels of intracellular cleaved caspase-9, cleaved caspase-3, Apaf-1, Bcl-2-associated X protein (Bax), and suppressor of fused (SuFu) increased, while B cell lymphoma 2 (Bcl-2) and Survivin decreased. What is more, in xenograft tumor model, hesperetin inhibited the tumor growth significantly via induction of cell apoptosis which was detected by TUNEL assay (p < 0.05). Taken together, our study demonstrated that hesperetin could induce cell apoptosis in esophageal cancer cells via mitochondrial-mediated intrinsic pathway by accumulation of ROS.

  2. Artificial immune system approach for air combat maneuvering

    NASA Astrophysics Data System (ADS)

    Kaneshige, John; Krishnakumar, Kalmanje

    2007-04-01

    Since future air combat missions will involve both manned and unmanned aircraft, the primary motivation for this research is to enable unmanned aircraft with intelligent maneuvering capabilities. During air combat maneuvering, pilots use their knowledge and experience of maneuvering strategies and tactics to determine the best course of action. As a result, we try to capture these aspects using an artificial immune system approach. The biological immune system protects the body against intruders by recognizing and destroying harmful cells or molecules. It can be thought of as a robust adaptive system that is capable of dealing with an enormous variety of disturbances and uncertainties. However, another critical aspect of the immune system is that it can remember how previous encounters were successfully defeated. As a result, it can respond faster to similar encounters in the future. This paper describes how an artificial immune system is used to select and construct air combat maneuvers. These maneuvers are composed of autopilot mode and target commands, which represent the low-level building blocks of the parameterized system. The resulting command sequences are sent to a tactical autopilot system, which has been enhanced with additional modes and an aggressiveness factor for enabling high performance maneuvers. Just as vaccinations train the biological immune system how to combat intruders, training sets are used to teach the maneuvering system how to respond to different enemy aircraft situations. Simulation results are presented, which demonstrate the potential of using immunized maneuver selection for the purposes of air combat maneuvering.

  3. Ride quality of terminal-area flight maneuvers

    NASA Technical Reports Server (NTRS)

    Schoonover, W. E., Jr.

    1975-01-01

    Complex terminal-area flight maneuvers being considered for airline operations may not be acceptable to passengers. To provide technology in this area, a series of flight experiments was conducted by NASA using the U. S. Air Force Total In-Flight Simulator (TIFS) aircraft to obtain subjective responses of a significant number of passenger test subjects to closely controlled and repeatable flight maneuvers. Regression analysis of the data produced a mathematical model which closely predicts mean passenger ride-comfort rating as a function of the rms six-degree-of-freedom aircraft motions during the maneuver. This ride-comfort model was exercised to examine various synthesized flight maneuvers.

  4. Coordination Logic for Repulsive Resolution Maneuvers

    NASA Technical Reports Server (NTRS)

    Narkawicz, Anthony J.; Munoz, Cesar A.; Dutle, Aaron M.

    2016-01-01

    This paper presents an algorithm for determining the direction an aircraft should maneuver in the event of a potential conflict with another aircraft. The algorithm is implicitly coordinated, meaning that with perfectly reliable computations and information, it will in- dependently provide directional information that is guaranteed to be coordinated without any additional information exchange or direct communication. The logic is inspired by the logic of TCAS II, the airborne system designed to reduce the risk of mid-air collisions between aircraft. TCAS II provides pilots with only vertical resolution advice, while the proposed algorithm, using a similar logic, provides implicitly coordinated vertical and horizontal directional advice.

  5. Large planar maneuvers for articulated flexible manipulators

    NASA Technical Reports Server (NTRS)

    Huang, Jen-Kuang; Yang, Li-Farn

    1988-01-01

    An articulated flexible manipulator carried on a translational cart is maneuvered by an active controller to perform certain position control tasks. The nonlinear dynamics of the articulated flexible manipulator are derived and a transformation matrix is formulated to localize the nonlinearities within the inertia matrix. Then a feedback linearization scheme is introduced to linearize the dynamic equations for controller design. Through a pole placement technique, a robust controller design is obtained by properly assigning a set of closed-loop desired eigenvalues to meet performance requirements. Numerical simulations for the articulated flexible manipulators are given to demonstrate the feasibility and effectiveness of the proposed position control algorithms.

  6. Maneuver strategies for multi-planet missions.

    NASA Technical Reports Server (NTRS)

    Dwivedi, N. P.

    1972-01-01

    This paper compares a number of maneuver strategies for five multi-planet missions, including the single planet strategy of nulling the aim-plane and flight-time errors at the immediate target. Significant differences were found among the strategies in the amount of corrective propellant required and the residual miss at each target. In general, nulling or minimization of the residual miss at the next target was found to be superior to that at the immediate target, when error growth is not nulled early. The best strategy corrects aim-plane and flight-time errors at the next target.

  7. Constitutive S-adenosylmethionine decarboxylase gene expression increases drought tolerance through inhibition of reactive oxygen species accumulation in Arabidopsis.

    PubMed

    Wi, Soo Jin; Kim, Soo Jin; Kim, Woo Taek; Park, Ky Young

    2014-05-01

    Using subtractive hybridization analysis, the S-adenosylmethionine decarboxylase (SAMDC) gene from Capsicum annuum was isolated and renamed CaSAMDC. We generated independent transgenic Arabidopsis (Arabidopsis thaliana) lines constitutively expressing a 35S::CaSAMDC construct. Drought tolerance was significantly enhanced in Arabidopsis T4 transgenic homozygous lines as compared to wild-type (WT) plants. The levels of main polyamines (PAs) were more significantly increased in CaSAMDC-overexpressing transgenic plants after 6 h of drought stress as compared to stressed WT plants. Basal transcription of polyamine oxidase (PAO) showed at a much higher level in unstressed-transgenic plants as compared to unstressed WT plants. However, the difference in PAO transcription level between WT and transgenic plants was reduced after drought stress. Cellular accumulation of reactive oxygen species (ROS) was significantly reduced following drought stress in transgenic Arabidopsis plants as compared to WT plants. These results were in agreement with additional observations that stress-induced ROS generation, as determined by qRT-PCR analysis of NADPH oxidase (RbohD and RbohF), was significantly suppressed while transcription of ROS-detoxifying enzymes was notably elevated in transgenic lines in response to drought stress. Further, ROS-induced transcription of the metacaspase II gene was remarkably inhibited in transgenic plants. Collectively, these results suggest that drought stress tolerance due to reduction of ROS production and enhancement of ROS detoxification can be attributed to elevation of PAs.

  8. Potato chip intake increases ascorbic acid levels and decreases reactive oxygen species in SMP30/GNL knockout mouse tissues.

    PubMed

    Kondo, Yoshitaka; Sakuma, Rui; Ichisawa, Megumi; Ishihara, Katsuyuki; Kubo, Misako; Handa, Setsuko; Mugita, Hiroyuki; Maruyama, Naoki; Koga, Hidenori; Ishigami, Akihito

    2014-09-24

    Potato chips (PC) contain abundant amounts of the free radical scavenger ascorbic acid (AA) due to the rapid dehydration of potato tubers (Solanum tuberosum) that occurs during frying. To evaluate the antioxidant activity of PC, this study examined reactive oxygen species (ROS) levels in tissues from SMP30/GNL knockout (KO) mice that cannot synthesize AA and determined AA and ROS levels after the animals were fed 20 and 10% PC diets for 7 weeks. Compared with AA-sufficient mice, AA-depleted SMP30/GNL KO mice showed high ROS levels in tissues. SMP30/GNL KO mice fed a PC diet showed high AA and low ROS levels in the brain, heart, lung, testis, soleus muscle, plantaris muscle, stomach, small intestine, large intestine, eyeball, and epididymal fat compared with AA-depleted mice. The data suggest that PC intake increases AA levels and enhances ROS scavenging activity in tissues of SMP30/GNL KO mice, which are a promising model for evaluating the antioxidant activity of foods. PMID:25180784

  9. Adventitious roots of wheat seedlings that emerge in oxygen-deficient conditions have increased root diameters with highly developed lysigenous aerenchyma.

    PubMed

    Yamauchi, Takaki; Abe, Fumitaka; Kawaguchi, Kentaro; Oyanagi, Atsushi; Nakazono, Mikio

    2014-01-01

    Exposing roots of plants to hypoxic conditions is known to greatly improve their anoxic stress tolerance. We previously showed that pre-treatment of wheat seedlings with an ethylene precursor, 1-aminocyclopropanecarboxylic acid (ACC), enhanced their tolerance of oxygen-deficient conditions. Although ACC-pretreated seminal roots of wheat seedlings grown under oxygen-deficient conditions avoided root tip death, they elongated very little. In the present study, we assessed the effects of ethylene on the responses of adventitious roots of wheat seedlings to oxygen-deficient conditions. Lysigenous aerenchyma formation in the adventitious roots of wheat seedlings pretreated with ACC appeared to reduce tip death under oxygen-deficient conditions, but the adventitious roots, like the seminal roots, hardly elongated. We also found that adventitious roots that emerge in oxygen-deficient conditions continued to elongate even under such conditions. The adventitious roots emerged in oxygen-deficient conditions were found to have thicker root diameters than those emerged in aerated conditions. These results suggest that the adventitious roots with thicker root diameters can better cope with oxygen-deficient conditions. Measurements of the area of the lysigenous aerenchyma confirmed that the increased root diameters have a greater amount of air space generated by lysigenous aerenchyma formation.

  10. Adventitious roots of wheat seedlings that emerge in oxygen-deficient conditions have increased root diameters with highly developed lysigenous aerenchyma.

    PubMed

    Yamauchi, Takaki; Abe, Fumitaka; Kawaguchi, Kentaro; Oyanagi, Atsushi; Nakazono, Mikio

    2014-01-01

    Exposing roots of plants to hypoxic conditions is known to greatly improve their anoxic stress tolerance. We previously showed that pre-treatment of wheat seedlings with an ethylene precursor, 1-aminocyclopropanecarboxylic acid (ACC), enhanced their tolerance of oxygen-deficient conditions. Although ACC-pretreated seminal roots of wheat seedlings grown under oxygen-deficient conditions avoided root tip death, they elongated very little. In the present study, we assessed the effects of ethylene on the responses of adventitious roots of wheat seedlings to oxygen-deficient conditions. Lysigenous aerenchyma formation in the adventitious roots of wheat seedlings pretreated with ACC appeared to reduce tip death under oxygen-deficient conditions, but the adventitious roots, like the seminal roots, hardly elongated. We also found that adventitious roots that emerge in oxygen-deficient conditions continued to elongate even under such conditions. The adventitious roots emerged in oxygen-deficient conditions were found to have thicker root diameters than those emerged in aerated conditions. These results suggest that the adventitious roots with thicker root diameters can better cope with oxygen-deficient conditions. Measurements of the area of the lysigenous aerenchyma confirmed that the increased root diameters have a greater amount of air space generated by lysigenous aerenchyma formation. PMID:25764431

  11. Adventitious roots of wheat seedlings that emerge in oxygen-deficient conditions have increased root diameters with highly developed lysigenous aerenchyma

    PubMed Central

    Yamauchi, Takaki; Abe, Fumitaka; Kawaguchi, Kentaro; Oyanagi, Atsushi; Nakazono, Mikio

    2014-01-01

    Exposing roots of plants to hypoxic conditions is known to greatly improve their anoxic stress tolerance. We previously showed that pre-treatment of wheat seedlings with an ethylene precursor, 1-aminocyclopropanecarboxylic acid (ACC), enhanced their tolerance of oxygen-deficient conditions. Although ACC-pretreated seminal roots of wheat seedlings grown under oxygen-deficient conditions avoided root tip death, they elongated very little. In the present study, we assessed the effects of ethylene on the responses of adventitious roots of wheat seedlings to oxygen-deficient conditions. Lysigenous aerenchyma formation in the adventitious roots of wheat seedlings pretreated with ACC appeared to reduce tip death under oxygen-deficient conditions, but the adventitious roots, like the seminal roots, hardly elongated. We also found that adventitious roots that emerge in oxygen-deficient conditions continued to elongate even under such conditions. The adventitious roots emerged in oxygen-deficient conditions were found to have thicker root diameters than those emerged in aerated conditions. These results suggest that the adventitious roots with thicker root diameters can better cope with oxygen-deficient conditions. Measurements of the area of the lysigenous aerenchyma confirmed that the increased root diameters have a greater amount of air space generated by lysigenous aerenchyma formation. PMID:24690588

  12. UVA irradiation of fatty acids and their oxidized products substantially increases their ability to generate singlet oxygen.

    PubMed

    Regensburger, Johannes; Maisch, Tim; Knak, Alena; Gollmer, Anita; Felgentraeger, Ariane; Lehner, Karin; Baeumler, Wolfgang

    2013-10-28

    UVA radiation plays an important role for adverse reactions in human tissue. UVA penetrates epidermis and dermis of skin being absorbed by various biomolecules, especially endogenous photosensitizers. This may generate deleterious singlet oxygen ((1)O2) that oxidizes fatty acids in cell membranes, lipoproteins, and other lipid-containing structures such as the epidermal barrier. Indications exist that fatty acids are not only the target of (1)O2 but also act as potential photosensitizers under UVA irradiation, if already oxidized. Five different fatty acids in ethanol solution (stearic, oleic, linoleic, linolenic and arachidonic acid) were exposed to UVA radiation (355 nm, 100 mW) for 30 seconds. (1)O2 luminescence was detected time-resolved at 1270 nm and confirmed in spectrally-resolved experiments. The more double bonds fatty acids have the more (1)O2 photons were detected. In addition, fatty acids were continuously exposed to broadband UVA for up to 240 min. During that time span, UVA absorption and (1)O2 luminescence substantially increased with irradiation time, reached a maximum and decreased again. HPLC-MS analysis showed that the amount of peroxidized fatty acids and the (1)O2 generation increased and decreased in parallel. This indicates the high potential of peroxidized fatty acids to produce (1)O2 under UVA irradiation. In conclusion, fatty acids along with peroxidized products are weak endogenous photosensitizers but become strong photosensitizers under continuous UVA irradiation. Since fatty acids and their oxidized products are ubiquitous in living cells and in skin, which is frequently and long-lasting exposed to UVA radiation, this photosensitizing effect may contribute to initiation of deleterious photooxidative processes in tissue.

  13. Thyrotrophin-releasing hormone decreases feeding and increases body temperature, activity and oxygen consumption in Siberian hamsters.

    PubMed

    Schuhler, S; Warner, A; Finney, N; Bennett, G W; Ebling, F J P; Brameld, J M

    2007-04-01

    Thyrotrophin-releasing hormone (TRH) is known to play an important role in the control of food intake and energy metabolism in addition to its actions on the pituitary-thyroid axis. We have previously shown that central administration of TRH decreases food intake in Siberian hamsters. This species is being increasingly used as a physiological rodent model in which to understand hypothalamic control of long-term changes in energy balance because it accumulates fat reserves in long summer photoperiods, and decreases food intake and body weight when exposed to short winter photoperiods. The objectives of our study in Siberian hamsters were: (i) to investigate whether peripheral administration of TRH would mimic the effects of central administration of TRH on food intake and whether these effects would differ dependent upon the ambient photoperiod; (ii) to determine whether TRH would have an effect on energy expenditure; and (iii) to investigate the potential sites of action of TRH. Both peripheral (5-50 mg/kg body weight; i.p.) and central (0.5 microg/ml; i.c.v.) administration of TRH decreased food intake, and increased locomotor activity, body temperature and oxygen consumption in the Siberian hamster, with a rapid onset and short duration of action. Systemic treatment with TRH was equally effective in suppressing feeding regardless of ambient photoperiod. The acute effects of TRH are likely to be centrally mediated and independent of its role in the control of the production of thyroid hormones. We conclude that TRH functions to promote a catabolic energetic state by co-ordinating acute central and chronic peripheral (thyroid-mediated) function.

  14. PIM Kinase Inhibitors Kill Hypoxic Tumor Cells by Reducing Nrf2 Signaling and Increasing Reactive Oxygen Species.

    PubMed

    Warfel, Noel A; Sainz, Alva G; Song, Jin H; Kraft, Andrew S

    2016-07-01

    Intratumoral hypoxia is a significant obstacle to the successful treatment of solid tumors, and it is highly correlated with metastasis, therapeutic resistance, and disease recurrence in cancer patients. As a result, there is an urgent need to develop effective therapies that target hypoxic cells within the tumor microenvironment. The Proviral Integration site for Moloney murine leukemia virus (PIM) kinases represent a prosurvival pathway that is upregulated in response to hypoxia, in a HIF-1-independent manner. We demonstrate that pharmacologic or genetic inhibition of PIM kinases is significantly more toxic toward cancer cells in hypoxia as compared with normoxia. Xenograft studies confirm that PIM kinase inhibitors impede tumor growth and selectively kill hypoxic tumor cells in vivo Experiments show that PIM kinases enhance the ability of tumor cells to adapt to hypoxia-induced oxidative stress by increasing the nuclear localization and activity of nuclear factor-erythroid 2 p45-related factor 2 (Nrf2), which functions to increase the expression of antioxidant genes. Small molecule PIM kinase inhibitors prevent Nrf2 from accumulating in the nucleus, reducing the transcription of cytoprotective genes and leading to the build-up of intracellular reactive oxygen species (ROS) to toxic levels in hypoxic tumor cells. This toxic effect of PIM inhibitors can be successfully blocked by ROS scavengers, including N-acetyl cystine and superoxide dismutase. Thus, inhibition of PIM kinases has the potential to oppose hypoxia-mediated therapeutic resistance and induce cell death in the hypoxic tumor microenvironment. Mol Cancer Ther; 15(7); 1637-47. ©2016 AACR. PMID:27196781

  15. Oxygen at 2 atmospheres absolute pressure does not increase the radiation sensitivity of normal brain in rats

    SciTech Connect

    Routh, A.; Kapp, J.P.; Smith, E.E.; Bebin, J.; Barnes, T.; Hickman, B.T.

    1984-07-01

    Cranial radiation was administered to CD Fisher rats at 1.0, 1.5 and 2.0 atmospheres oxygen pressure. Life span following radiation was recorded. Surviving animals were killed at 28 weeks and the brains were examined independently by two neuropathologists. Survival time was significantly less in animals receiving higher doses of radiation but showed no relationship to the oxygen pressure in the environment of the animal at the time radiation was administered. Microscopic examination of the brain did not reveal any differences in animals radiated in a normobaric or hyperbaric oxygen environment. It is concluded that hyperbaric oxygen does not sensitize the normal brain to the effects of ionizing radiation.

  16. The manned maneuvering unit flight controller arm

    NASA Technical Reports Server (NTRS)

    Falkner, K. E.

    1983-01-01

    The Manned Maneuvering Unit (MMU) and its support equipment provide an extravehicular astronaut mobility, and the ability to work outside the confines of the Shuttle Orbiter payload bay. The MMU design requirements are based on the highly successful Skylab M-509 maneuvering unit. Design of the MMU was started as an R&D effort in April 1975 and Flight Hardware design was started in August 1979 to support a possible requirement for in-space inspection and repair of Orbiter thermal protection tiles. Subsequently, the qualification test and production activities were slowed, and the current projected earliest first flight is now STS-11 in January, 1984. The MMU propulsion subsystem provides complete redundancy with two identical "system". Each system contains a high pressure gaseous nitrogen tank, an isolation valve, a regulator, and twelve 1.7 lbf (7.5 N) thrusters. The thrusters are packaged to provide the crew member six-degree-of-freedom control in response to commands from translational and rotational hand controllers. This paper discusses the MMU control arm requirements, design, and developmental history.

  17. Association of renal injury with increased oxygen free radical activity and altered nitric oxide metabolism in chronic experimental hemosiderosis.

    PubMed

    Zhou, X J; Laszik, Z; Wang, X Q; Silva, F G; Vaziri, N D

    2000-12-01

    Chronic iron (Fe) overload is associated with a marked increase in renal tissue iron content and injury. It is estimated that 10% of the American population carry the gene for hemochromatosis and 1% actually suffer from iron overload. The mechanism of iron overload-associated renal damage has not been fully elucidated. Iron can accelerate lipid peroxidation leading to organelle membrane dysfunction and subsequent cell injury/death. Iron-catalyzed generation of reactive oxygen species (ROS) is responsible for initiating the peroxidatic reaction. We investigated the possible association of oxidative stress and its impact on nitric oxide (NO) metabolism in iron-overload-associated renal injury. Rats were randomized into Fe-loaded (given 0.5 g elemental iron/kg body weight as iron dextran; i.v.), Fe-depleted (given an iron-free diet for 20 weeks), and control groups. Renal histology, tissue expression of endothelial and inducible nitric oxide synthases (eNOS and iNOS), renal tissue expression of nitrotyrosine, plasma, and renal tissue lipid peroxidation product, malondialdehyde (MDA), and plasma and urinary NO metabolites (NOx) were examined. Iron overload was associated with mild proteinuria, tissue iron deposition together with significant glomerulosclerosis, tubular atrophy, and interstitial fibrosis. Rare focal glomerulosclerosis and tubulointerstitial changes were noted in normal controls. No renal lesions were observed in Fe-depleted rats. Iron deposits were seen in glomeruli, proximal tubules, and interstitium. The iron staining in the distal tubules was negligible. Both plasma and renal tissue MDA and renal tissue nitrotyrosine were increased significantly in Fe-loaded rats compared with control rats. In contrast, Fe-depleted animals showed a marked reduction in plasma and renal tissue MDA and nitrotyrosine together with significant elevation of urinary NOx excretion. In addition, iron-overload was associated with up-regulation of renal eNOS and i

  18. Gene expression profiling reveals decreased expression of two hemoglobin genes associated with increased consumption of oxygen in Chironomus tentans exposed to atrazine: a possible mechanism for adapting to oxygen deficiency.

    PubMed

    Anderson, Troy D; Jin-Clark, Ying; Begum, Khurshida; Starkey, Sharon R; Zhu, Kun Yan

    2008-01-31

    Atrazine is an extensively used triazine herbicide in agricultural and residential areas and has been routinely detected in many surface and ground waters. This study reveals various up- and down-regulated genes associated with hypoxic stress in atrazine-treated fourth-instar Chironomus tentans larvae (midges) by using restriction fragment differential display-PCR. Two down-regulated hemoglobin cDNAs were isolated from the midges. Northern blot analysis indicated CteHb-IIbeta and CteHb-III mRNA expressions decreased by 36 and 21%, respectively, in midges exposed to atrazine at 1 microg/L for 96h. Decreased hemoglobin gene expression was associated with elevated oxygen consumption in atrazine-treated midges. Midges exposed to atrazine at 1 microg/L increased their oxygen consumption by 47%, whereas midges exposed to atrazine at 1000 microg/L for 48h increased their oxygen consumption by 66%. Our study demonstrates for the first time that atrazine, at environmentally relevant concentrations, can elevate respiration, possibly eliciting counteractive measures at the transcriptional level to adapt to oxygen deficiency in an ecologically important aquatic insect. Our results further suggest that the ability to modulate both the quantity and quality of Hb serves as an adaptive response to counteract the initial onset of oxygen deficiency induced by atrazine in midges.

  19. Accuracy of different oxygenation indices in estimating intrapulmonary shunting at increasing infusion rates of dobutamine in horses under general anaesthesia.

    PubMed

    Briganti, A; Portela, D A; Grasso, S; Sgorbini, M; Tayari, H; Bassini, J R Fusar; Vitale, V; Romano, M S; Crovace, A; Breghi, G; Staffieri, F

    2015-06-01

    The aim of this study was to evaluate the correlation of commonly used oxygenation indices with venous admixture (Qs/Qt) in anaesthetised horses under different infusion rates of dobutamine. Six female horses were anaesthetised with acepromazine, xylazine, diazepam, ketamine, and isoflurane, and then intubated and mechanically ventilated with 100% O2. A Swan-Ganz catheter was introduced into the left jugular vein and its tip advanced into the pulmonary artery. Horses received different standardised rates of dobutamine. For each horse, eight samples of arterial and mixed venous blood were simultaneously obtained at fixed times. Arterial and venous haemoglobin (Hb) concentration and O2 saturation, arterial oxygen partial pressure (PaO2), venous oxygen partial pressure (PvO2), and barometric pressure were measured. Arterial (CaO2), mixed venous (CvO2), and capillary (Cc'O2) oxygen contents were calculated using standard formulae. The correlations between F-shunt, arterial oxygen tension to fraction of inspired oxygen ratio (PaO2/FiO2), arterial to alveolar oxygen tension ratio (PaO2/PAO2), alveolar to arterial oxygen tension difference (P[A - a]O2), and respiratory index (P[A - a]O2/PaO2) were tested with linear regression analysis. The goodness-of-fit for each calculated formula was evaluated by means of the coefficient of determination (r(2)). The agreement between Qs/Qt and F-shunt was analysed with the Bland-Altman test. All tested oxygen tension-based indices were weakly correlated (r(2) < 0.2) with the Qs/Qt, whereas F-shunt showed a stronger correlation (r(2) = 0.73). F-shunt also showed substantial agreement with Qs/Qt independent of the dobutamine infusion rate. F-shunt better correlated with Qs/Qt than other oxygen indices in isoflurane-anaesthetised horses under different infusion rates of dobutamine. PMID:25920771

  20. Conflict Resolution Performance in an Experimental Study of En Route Free Maneuvering Operations

    NASA Technical Reports Server (NTRS)

    Doble, Nathan A.; Barhydt, Richard; Hitt, James M., II

    2005-01-01

    NASA has developed a far-term air traffic management concept, termed Distributed Air/Ground Traffic Management (DAG-TM). One component of DAG-TM, En Route Free Maneuvering, allows properly trained flight crews of equipped autonomous aircraft to assume responsibility for separation from other autonomous aircraft and from Instrument Flight Rules (IFR) aircraft. Ground-based air traffic controllers continue to separate IFR traffic and issue flow management constraints to all aircraft. To examine En Route Free Maneuvering operations, a joint human-in-the-loop experiment was conducted in summer 2004 at the NASA Ames and Langley Research Centers. Test subject pilots used desktop flight simulators to resolve traffic conflicts and adhere to air traffic flow constraints issued by subject controllers. The experimental airspace integrated both autonomous and IFR aircraft at varying traffic densities. This paper presents a subset of the En Route Free Maneuvering experimental results, focusing on airborne and ground-based conflict resolution, and the effects of increased traffic levels on the ability of pilots and air traffic controllers to perform this task. The results show that, in general, increases in autonomous traffic do not significantly impact conflict resolution performance. In addition, pilot acceptability of autonomous operations remains high throughout the range of traffic densities studied. Together with previously reported findings, these results continue to support the feasibility of the En Route Free Maneuvering component of DAG-TM.

  1. Gender differences in hip adduction motion and torque during a single-leg agility maneuver.

    PubMed

    Hewett, Timothy E; Ford, Kevin R; Myer, Gregory D; Wanstrath, Kim; Scheper, Melia

    2006-03-01

    The purpose of this study was to identify gender differences in hip motion and kinetics during a single leg bidirectional deceleration maneuver. The rationale for the development of this maneuver was to test dynamic hip control during the deceleration of three different types of single-leg landings. The hypothesis was that female athletes would display increased hip adduction angles and moments during the maneuver compared to male athletes. Thirty-six collegiate soccer players (19 female, 17 male) volunteered to participate. Subjects were instructed to start the maneuver balancing on one foot, to hop through an agility-speed ladder on the same leg "up two boxes, back one, and then up one and hold it." Hip kinematics and kinetics during all three landings were examined. Females demonstrated significantly greater hip adduction angles at initial contact during all three landings and greater maximal hip adduction during landings 1 and 2 compared to male athletes. Females also exhibited significantly increased external hip adduction moments during landing 1, however, no differences were found between genders during landings 2 and 3.

  2. Induction of inducible nitric oxide synthase increases the production of reactive oxygen species in RAW264.7 macrophages.

    PubMed

    Zhao, Kai; Huang, Zhen; Lu, Hongling; Zhou, Juefei; Wei, Taotao

    2010-08-01

    Macrophages produce a large volume of ROS (reactive oxygen species) through respiratory burst. However, the influence of iNOS [inducible NOS (nitric oxide synthase)] activation on ROS production remains unclear. In the present study, the kinetic generation of ROS in RAW264.7 murine macrophages was monitored by chemiluminescence. PMA induces a robust chemiluminescence in RAW264.7 cells, suggesting PKC (protein kinase C)-related assembly and activation of NOX (NADPH oxidase). The effects of iNOS induction on ROS production were examined. Induction of iNOS expression in RAW264.7 cells with LPS (lipopolysaccharide; 1 microg/ml) causes a significant increase in PMA-induced chemiluminescence, which could be enhanced by the NOS substrate, L-arginine, and could be abolished by the NOS inhibitor, L-NNA (NG-nitro-L-arginine). Further experiments reveal that induction of iNOS expression enhances the PMA-stimulated phosphorylation of the p47phox subunit of NOX, and promotes the relocalization of cytosolic p47phox and p67phox subunits to the membrane. Inhibition of PKCzeta by its myristoylated pseudosubstrate significantly decreased the PMA-stimulated phosphorylation of the p47phox in LPS-pretreated cells, suggesting that PKCzeta is involved in the iNOS-dependent assembly and activation of NOX. Taken together, the present study suggests that the induction of iNOS upregulates the PMA-induced assembly of NOX and leads to the enhanced production of ROS via a PKCzeta-dependent mechanism. PMID:19673702

  3. Instantaneous Observability of Tightly Coupled SINS/GPS during Maneuvers.

    PubMed

    Jiang, Junxiang; Yu, Fei; Lan, Haiyu; Dong, Qianhui

    2016-01-01

    The tightly coupled strapdown inertial navigation system (SINS)/global position system (GPS) has been widely used. The system observability determines whether the system state can be estimated by a filter efficiently or not. In this paper, the observability analysis of a two-channel and a three-channel tightly coupled SINS/GPS are performed, respectively, during arbitrary translational maneuvers and angle maneuvers, where the translational maneuver and angle maneuver are modeled. A novel instantaneous observability matrix (IOM) based on a reconstructed psi-angle model is proposed to make the theoretical analysis simpler, which starts from the observability definition directly. Based on the IOM, a series of theoretical analysis are performed. Analysis results show that almost all kinds of translational maneuver and angle maneuver can make a three-channel system instantaneously observable, but there is no one translational maneuver or angle maneuver can make a two-channel system instantaneously observable. The system's performance is investigated when the system is not instantaneously observable. A series of simulation studies based on EKF are performed to confirm the analytic conclusions. PMID:27240369

  4. Maneuver of juvenile chinook salmon during feeding in streams

    NASA Astrophysics Data System (ADS)

    Peng, Jifeng

    2010-11-01

    Before they head to the ocean, juvenile chinook salmon O. tshawytscha habitat in freshwater rivers and feed on small invertebrates drifting in streams. During drift-feeding, these fish hold fairly steady positions in the flow facing upstream, and maneuver to intercept drifting prey as it passes. They have a large arsenal of maneuver modes, which presumably enable them to maximize prey encounter while keeping energy expense low. Moreover, because these fish often gather in schools, they utilize their maneuvers so that they do not invade others' territories. In this study, we measured three-dimensional motion of juvenile chinook salmon in situ during feeding. The kinematics of some of the widely-used maneuvers, including slow lateral motion, sharp U-shaped turn and fast S-shaped turn, were analyzed. A computational model based on ideal fluid theory was developed to estimate the dynamics of these maneuvers. Energetics of the maneuvers was evaluated, together with effects on prey encounter, in order to compare and explain the choices of maneuvers in different situations. The effects of neighbors in a fish school on individual maneuvers were also studied.

  5. 14 CFR 23.155 - Elevator control force in maneuvers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... needed to achieve the positive limit maneuvering load factor may not be less than: (1) For wheel controls... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Elevator control force in maneuvers. 23.155... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES...

  6. 14 CFR 23.155 - Elevator control force in maneuvers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... needed to achieve the positive limit maneuvering load factor may not be less than: (1) For wheel controls... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Elevator control force in maneuvers. 23.155... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES...

  7. 14 CFR 23.155 - Elevator control force in maneuvers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... needed to achieve the positive limit maneuvering load factor may not be less than: (1) For wheel controls... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Elevator control force in maneuvers. 23.155... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES...

  8. 14 CFR 25.1531 - Maneuvering flight load factors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maneuvering flight load factors. 25.1531 Section 25.1531 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... positive limit load factors determined from the maneuvering diagram in § 25.333(b), must be established....

  9. 14 CFR 25.1531 - Maneuvering flight load factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Maneuvering flight load factors. 25.1531 Section 25.1531 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... positive limit load factors determined from the maneuvering diagram in § 25.333(b), must be established....

  10. Instantaneous Observability of Tightly Coupled SINS/GPS during Maneuvers

    PubMed Central

    Jiang, Junxiang; Yu, Fei; Lan, Haiyu; Dong, Qianhui

    2016-01-01

    The tightly coupled strapdown inertial navigation system (SINS)/global position system (GPS) has been widely used. The system observability determines whether the system state can be estimated by a filter efficiently or not. In this paper, the observability analysis of a two-channel and a three-channel tightly coupled SINS/GPS are performed, respectively, during arbitrary translational maneuvers and angle maneuvers, where the translational maneuver and angle maneuver are modeled. A novel instantaneous observability matrix (IOM) based on a reconstructed psi-angle model is proposed to make the theoretical analysis simpler, which starts from the observability definition directly. Based on the IOM, a series of theoretical analysis are performed. Analysis results show that almost all kinds of translational maneuver and angle maneuver can make a three-channel system instantaneously observable, but there is no one translational maneuver or angle maneuver can make a two-channel system instantaneously observable. The system’s performance is investigated when the system is not instantaneously observable. A series of simulation studies based on EKF are performed to confirm the analytic conclusions. PMID:27240369

  11. 14 CFR 25.331 - Symmetric maneuvering conditions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...) Maneuvering balanced conditions. Assuming the airplane to be in equilibrium with zero pitching acceleration... cockpit pitch control is suddenly moved to obtain extreme nose up pitching acceleration. In defining the... subsequent to the time when normal acceleration at the c.g. exceeds the positive limit maneuvering...

  12. 14 CFR 25.331 - Symmetric maneuvering conditions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...) Maneuvering balanced conditions. Assuming the airplane to be in equilibrium with zero pitching acceleration... cockpit pitch control is suddenly moved to obtain extreme nose up pitching acceleration. In defining the... subsequent to the time when normal acceleration at the c.g. exceeds the positive limit maneuvering...

  13. 14 CFR 25.331 - Symmetric maneuvering conditions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) Maneuvering balanced conditions. Assuming the airplane to be in equilibrium with zero pitching acceleration... cockpit pitch control is suddenly moved to obtain extreme nose up pitching acceleration. In defining the... subsequent to the time when normal acceleration at the c.g. exceeds the positive limit maneuvering...

  14. 14 CFR 25.331 - Symmetric maneuvering conditions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) Maneuvering balanced conditions. Assuming the airplane to be in equilibrium with zero pitching acceleration... cockpit pitch control is suddenly moved to obtain extreme nose up pitching acceleration. In defining the... subsequent to the time when normal acceleration at the c.g. exceeds the positive limit maneuvering...

  15. 14 CFR 25.331 - Symmetric maneuvering conditions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...) Maneuvering balanced conditions. Assuming the airplane to be in equilibrium with zero pitching acceleration... cockpit pitch control is suddenly moved to obtain extreme nose up pitching acceleration. In defining the... subsequent to the time when normal acceleration at the c.g. exceeds the positive limit maneuvering...

  16. Teleoperator Maneuvering System (TMS) mission applications and benefits

    NASA Technical Reports Server (NTRS)

    Cramblit, D. C.; Turner, J. R.

    1984-01-01

    Studies conducted by NASA have shown that the operating range of the Shuttle can be substantially increased and cost of payload operation be decreased by making use of the Teleoperator Maneuvering System (TMS). The TMS is remotely controlled, free-flying, orbital mini-tug vehicle capable of performing a wide range of remote satellite services missions. It can operate out of the Shuttle cargo bay, from a space station, or on top of an upper stage like Centaur. For high energy missions up to and including geostationary orbit, the TMS propulsion stage will augment the Transfer Orbit Stage (TOS) recently proposed for commercial development in providing an effective low-cost second-stage system for delivering intermediate sized payloads to geosynchronous orbit (GEO). Attention is given to TMS capabilities for both long duration and short term orbital missions, taking into account also Space Station support operations.

  17. Planar reorientation maneuvers of space multibody systems using internal controls

    NASA Technical Reports Server (NTRS)

    Reyhanoglu, Mahmut; Mcclamroch, N. H.

    1992-01-01

    In this paper a reorientation maneuvering strategy for an interconnection of planar rigid bodies in space is developed. It is assumed that there are no exogeneous torques, and torques generated by joint motors are used as means of control so that the total angular momentum of the multibody system is a constant, assumed to be zero in this paper. The maneuver strategy uses the nonintegrability of the expression for the angular momentum. We demonstrate that large-angle maneuvers can be designed to achieve an arbitrary reorientation of the multibody system with respect to an inertial frame. The theoretical background for carrying out the required maneuvers is briefly summarized. Specifications and computer simulations of a specific reorientation maneuver, and the corresponding control strategies, are described.

  18. Optimization of Maneuver Execution for Landsat-7 Routine Operations

    NASA Technical Reports Server (NTRS)

    Cox, E. Lucien, Jr.; Bauer, Frank H. (Technical Monitor)

    2000-01-01

    Multiple mission constraints were satisfied during a lengthy, strategic ascent phase. Once routine operations begin, the ongoing concern of maintaining mission requirements becomes an immediate priority. The Landsat-7 mission has tight longitude control box and Earth imaging that requires sub-satellite descending nodal equator crossing times to occur in a narrow 30minute range fifteen (15) times daily. Operationally, spacecraft maneuvers must'be executed properly to maintain mission requirements. The paper will discuss the importance of optimizing the altitude raising and plane change maneuvers, amidst known constraints, to satisfy requirements throughout mission lifetime. Emphasis will be placed not only on maneuver size and frequency but also on changes in orbital elements that impact maneuver execution decisions. Any associated trade-off arising from operations contingencies will be discussed as well. Results of actual altitude and plane change maneuvers are presented to clarify actions taken.

  19. Performance Evaluation of Evasion Maneuvers for Parallel Approach Collision Avoidance

    NASA Technical Reports Server (NTRS)

    Winder, Lee F.; Kuchar, James K.; Waller, Marvin (Technical Monitor)

    2000-01-01

    Current plans for independent instrument approaches to closely spaced parallel runways call for an automated pilot alerting system to ensure separation of aircraft in the case of a "blunder," or unexpected deviation from the a normal approach path. Resolution advisories by this system would require the pilot of an endangered aircraft to perform a trained evasion maneuver. The potential performance of two evasion maneuvers, referred to as the "turn-climb" and "climb-only," was estimated using an experimental NASA alerting logic (AILS) and a computer simulation of relative trajectory scenarios between two aircraft. One aircraft was equipped with the NASA alerting system, and maneuvered accordingly. Observation of the rates of different types of alerting failure allowed judgement of evasion maneuver performance. System Operating Characteristic (SOC) curves were used to assess the benefit of alerting with each maneuver.

  20. Validation of the qCO cardiac output monitor during Valsalva maneuver.

    PubMed

    Jospin, Mathieu; Aguilar, Juan P; Gambus, Pedro L; Jensen, Erik W; Vallverdu, Montserrat; Caminal, Pere

    2012-01-01

    Monitoring cardiac output for a variety of patient conditions is essential to ensure tissue perfusion and oxygenation. Cardiac output can be measured either invasively using a pulmonary artery catheter or non-invasively using impedance cardiography (ICG). The objective of the present study was to validate a cardiac output monitor, the qCO (Quantium Medical, Barcelona, Spain). The qCO is based on the ICG principle. Twenty-five volunteers (18-75 years) were enrolled in the study. The duration of the study was 10 min. The subjects were asked to rest quietly in an armchair for a duration of 5 min. At 5 min they were asked to do a Valsalva maneuver which is known to decrease the cardiac output. The baseline value of the normalized cardiac output (qCO index) was compared with the minimum value during the Valsalva maneuver. The results showed (t-test, p<0.0005) significant difference between the cardiac output estimated at baseline and during the Valsalva maneuver. In conclusion, the qCO was able to indicate trend changes of the cardiac output in volunteers.

  1. Control of a high beta maneuvering reentry vehicle using dynamic inversion.

    SciTech Connect

    Watts, Alfred Chapman

    2005-05-01

    The design of flight control systems for high performance maneuvering reentry vehicles presents a significant challenge to the control systems designer. These vehicles typically have a much higher ballistic coefficient than crewed vehicles like as the Space Shuttle or proposed crew return vehicles such as the X-38. Moreover, the missions of high performance vehicles usually require a steeper reentry flight path angle, followed by a pull-out into level flight. These vehicles then must transit the entire atmosphere and robustly perform the maneuvers required for the mission. The vehicles must also be flown with small static margins in order to perform the required maneuvers, which can result in highly nonlinear aerodynamic characteristics that frequently transition from being aerodynamically stable to unstable as angle of attack increases. The control system design technique of dynamic inversion has been applied successfully to both high performance aircraft and low beta reentry vehicles. The objective of this study was to explore the application of this technique to high performance maneuvering reentry vehicles, including the basic derivation of the dynamic inversion technique, followed by the extension of that technique to the use of tabular trim aerodynamic models in the controller. The dynamic inversion equations are developed for high performance vehicles and augmented to allow the selection of a desired response for the control system. A six degree of freedom simulation is used to evaluate the performance of the dynamic inversion approach, and results for both nominal and off nominal aerodynamic characteristics are presented.

  2. Analysis of ship maneuvering data from simulators

    NASA Astrophysics Data System (ADS)

    Frette, V.; Kleppe, G.; Christensen, K.

    2011-03-01

    We analyze complex manuevering histories of ships obtained from training sessions on bridge simulators. Advanced ships are used in fields like offshore oil exploration: dive support vessels, supply vessels, anchor handling vessels, tugs, cable layers, and multi-purpose vessels. Due to high demands from the operations carried out, these ships need to have very high maneuverability. This is achieved through a propulsion system with several thrusters, water jets, and rudders in addition to standard propellers. For some operations, like subsea maintenance, it is crucial that the ship accurately keeps a fixed position. Therefore, bridge systems usually incorporate equipment for Dynamic Positioning (DP). DP is a method to keep ships and semi submersible rigs in a fixed position using the propulsion systems instead of anchors. It may also be used for sailing a vessel from one position to another along a predefined route. Like an autopilot on an airplane, DP may operate without human involvement. The method relies on accurate determination of position from external reference systems like GPS, as well as a continuously adjusted mathematical model of the ship and external forces from wind, waves and currents. In a specific simulator exercise for offshore crews, a ship is to be taken up to an installation consisting of three nearby oil platforms connected by bridges (Frigg field, North Sea), where a subsea inspection is to be carried out. Due to the many degrees of freedom during maneuvering, including partly or full use of DP, the chosen routes vary significantly. In this poster we report preliminary results on representations of the complex maneuvering histories; representations that allow comparison between crew groups, and, possibly, sorting of the different strategic choices behind.

  3. Ocular VEMPs indicate repositioning of otoconia to the utricle after successful liberatory maneuvers in benign paroxysmal positioning vertigo

    PubMed Central

    BREMOVA, TATIANA; BAYER, OTMAR; AGRAWAL, YURI; KREMMYDA, OLYMPIA; BRANDT, THOMAS; TEUFEL, JULIAN; STRUPP, MICHAEL

    2014-01-01

    Conclusions This study showed a transient increase of ocular vestibular evoked myogenic potential (oVEMP) amplitudes in the affected ear after successful liberatory maneuvers and no changes in cervical VEMP (cVEMP) amplitudes. These findings support the hypothesis that successful liberatory maneuvers can lead to a repositioning of otoconia to the utricle. Objectives To evaluate whether oVEMP amplitudes increase after successful liberatory maneuvers in patients with posterior semicircular canal benign paroxysmal positioning vertigo (pc-BPPV), while cVEMP amplitudes do not change. These findings may indicate a successful repositioning of dislodged otoconia to the utricular macula, but not to the saccular macula. Methods Thirty patients with unilateral pc-BPPV were prospectively examined with bone-conducted oVEMP and air-conducted cVEMP at four time points: before, after, 1 week after, and 1 month after the liberatory maneuvers (Sémont maneuvers). Results At the 1-week follow-up, 20 of 30 patients were asymptomatic (responders); BPPV could still be induced in the other 10 (non-responders). In responders the mean n10 amplitude on the affected side increased from 12 ± 6.5 μV at baseline (before the treatment) to 15.9 ± 7.1 μV at 1 week after treatment; this increase was significantly (p = 0.001) higher in responders than in non-responders. cVEMP did not differ significantly. PMID:24245699

  4. Hemodynamic responses during and after multiple sets of stretching exercises performed with and without the Valsalva maneuver

    PubMed Central

    Lima, Tainah P.; Farinatti, Paulo T.V.; Rubini, Ercole C.; Silva, Elirez B.; Monteiro, Walace D.

    2015-01-01

    OBJECTIVE: This study investigated the acute hemodynamic responses to multiple sets of passive stretching exercises performed with and without the Valsalva maneuver. METHODS: Fifteen healthy men aged 21 to 29 years with poor flexibility performed stretching protocols comprising 10 sets of maximal passive unilateral hip flexion, sustained for 30 seconds with equal intervals between sets. Protocols without and with the Valsalva maneuver were applied in a random counterbalanced order, separated by 48-hour intervals. Hemodynamic responses were measured by photoplethysmography pre-exercise, during the stretching sets, and post-exercise. RESULTS: The effects of stretching sets on systolic and diastolic blood pressure were cumulative until the fourth set in protocols performed with and without the Valsalva maneuver. The heart rate and rate pressure product increased in both protocols, but no additive effect was observed due to the number of sets. Hemodynamic responses were always higher when stretching was performed with the Valsalva maneuver, causing an additional elevation in the rate pressure product. CONCLUSIONS: Multiple sets of unilateral hip flexion stretching significantly increased blood pressure, heart rate, and rate pressure product values. A cumulative effect of the number of sets occurred only for systolic and diastolic blood pressure, at least in the initial sets of the stretching protocols. The performance of the Valsalva maneuver intensified all hemodynamic responses, which resulted in significant increases in cardiac work during stretching exercises. PMID:26039949

  5. Oxygen safety

    MedlinePlus

    COPD - oxygen safety; Chronic obstructive pulmonary disease - oxygen safety; Chronic obstructive airways disease - oxygen safety; Emphysema - oxygen safety; Heart failure - oxygen-safety; Palliative care - oxygen safety; ...

  6. A Low Speed Maneuvering Technology for Docking of Unmanned Underwater Vehicles

    NASA Astrophysics Data System (ADS)

    Mohseni, K.

    2006-12-01

    Reliable docking mechanisms are essential for operation of AUV networks in harsh environment such as under ice in polar region. Hydrodynamic design of AUVs are often driven on a few competing fronts: (i) Rapid and efficient deployment to the work-zone and (ii) low speed maneuvering during the docking procedure and for operations at the work-zone. Rapid deployment necessitates a streamlined body of revolution (eg. Torpedo- shape design) for fast cruising with minimal energy. However, since the trajectory of this type of vehicles is adjusted using control surfaces, the magnitude of the available control force is proportional to the vehicle's speed. Consequently, these vehicles are difficult to maneuver at low speeds and in tight spaces. Therefore, they are particularly difficult to dock. Such vehicles also cannot opportunistically enter a precise loitering or hovering mode. As a result much current effort is devoted to the development of docking mechanisms, but this is just a solution for the symptoms, and does not really address the problem of the vehicle's actual maneuvering capabilities. On the other hand, low speed maneuvering and better control are often achieved by the so-called box-design where the low drag body-of-revolution design is sacrificed by adding multiple thrusters at different locations and directions. In this case, precise maneuvering can be achieved at the cost of increased drag and the need for an alternate technique to transport the vehicle from the offshore base or an escort ship to the work-zone. In an effort to resolve this trade-off, we have recently proposed to use compact synthetic jets for low speed maneuvering or locomotion of small unmanned underwater vehicles (UUVs). Inspired by the propulsion of cephalopod, we have designed and implemented compact vortex generators for low speed maneuvering, station keeping, and docking of small underwater vehicles. Design, fabrication, thrust optimization, and implementation of such compact actuators

  7. Dynamics of spacecraft control laboratory experiment (SCOLE) slew maneuvers

    NASA Technical Reports Server (NTRS)

    Kakad, Y. P.

    1987-01-01

    This is the first of two reports on the dynamics and control of slewing maneuvers of the NASA Spacecraft Control Laboratory Experiment (SCOLE). In this report, the dynamics of slewing maneuvers of SCOLE are developed in terms of an arbitrary maneuver about any given axis. The set of dynamical equations incorporate rigid-body slew maneuver and three-dimensional vibrations of the complete assembly comprising the rigid shuttle, the flexible beam, and the reflector with an offset mass. The analysis also includes kinematic nonlinearities of the entire assembly during the maneuver and the dynamics of the interaction between the rigid shuttle and the flexible appendage. The final set of dynamical equations obtained for slewing maneuvers is highly nonlinear and coupled in terms of the flexible modes and the rigid-body modes. The equations are further simplified and evaluated numerically to include the first ten flexible modes and the SCOLE data to yield a model for designing control systems to perform slew maneuvers.

  8. Active oxygen species mediate the solar ultraviolet radiation-dependent increase in the tumour suppressor protein p53 in human skin fibroblasts.

    PubMed

    Vile, G F

    1997-07-21

    Active oxygen species mediate many of the biological consequences of exposing cultured human skin cells to solar ultraviolet (UV) radiation (290-380 nm). A critical step in the escape from the carcinogenic potential of UV radiation is mediated by the protein p53. P53 activates growth arrest, allowing for DNA repair, and apoptosis, which removes damaged cells. Here I show that p53 in cultured human skin fibroblasts is elevated after treatment with hydrogen peroxide, an oxidant produced in cells during exposure to solar UV radiation. Simulated solar UV radiation increased p53, and agents that scavenge active oxygen species, N-acetylcysteine, ascorbate and alpha-tocopherol, inhibited the increase. The generation of DNA single strand breaks has been proposed to be an important step in the pathway leading to the increase in p53 initiated by a variety of cytotoxic agents. In this study I show that compounds that allow the accumulation of DNA single strand breaks, ara c and hydroxyurea, enhanced the UVC radiation (254 nm)-dependent increase in p53, but had no effect on the solar UV radiation-dependent increase. Thus, while DNA single strand breaks are involved in the UVC radiation-dependent increase in p53, the increase caused by solar UV radiation occurs by an alternative mechanism involving active oxygen species.

  9. An Approach for Hydrogen Recycling in a Closed-loop Life Support Architecture to Increase Oxygen Recovery Beyond State-of-the-Art

    NASA Technical Reports Server (NTRS)

    Abney, Morgan B.; Miller, Lee; Greenwood, Zachary; Alvarez, Giraldo

    2014-01-01

    State-of-the-art atmosphere revitalization life support technology on the International Space Station is theoretically capable of recovering 50% of the oxygen from metabolic carbon dioxide via the Carbon Dioxide Reduction Assembly (CRA). When coupled with a Plasma Pyrolysis Assembly (PPA), oxygen recovery increases dramatically, thus drastically reducing the logistical challenges associated with oxygen resupply. The PPA decomposes methane to predominantly form hydrogen and acetylene. Because of the unstable nature of acetylene, a down-stream separation system is required to remove acetylene from the hydrogen stream before it is recycled to the CRA. A new closed-loop architecture that includes a PPA and downstream Hydrogen Purification Assembly (HyPA) is proposed and discussed. Additionally, initial results of separation material testing are reported.

  10. Maneuver Design for the Juno Mission: Inner Cruise

    NASA Technical Reports Server (NTRS)

    Pavlak, Thomas A.; Frauenholz, Raymond B.; Bordi, John J.; Kangas, Julie A.; Helfrich, Clifford E.

    2014-01-01

    The Juno spacecraft launched in August 2011 and, following a successful Earth flyby in October 2013, is on course for a nominal orbit insertion at Jupiter in July 2016. This paper examines the design and execution of deterministic and statistical trajectory correction maneuvers during the first approximately 27 months of post-launch operations that defined the "Inner Cruise" phase of the Juno mission. Topics of emphasis include the two deep space maneuvers, Earth flyby altitude biasing strategy, and the sequence of trajectory correction maneuvers executed in the weeks prior to the successful Earth gravity assist.

  11. Cassini-Huygens Maneuver Experience: Ending the Prime Mission

    NASA Technical Reports Server (NTRS)

    Goodson, Troy D.; Ballard, Christopher G.; Gist, Emily M.; Hahn, Yungsun; Stumpf, Paul W.; Wagner, Sean V.; Williams, Powtawche N.

    2008-01-01

    The Cassini-Huygens spacecraft was launched in 1997 on a mission to observe Saturn and its many moons. After a seven-year cruise, it entered a Saturnian orbit for a four-year, prime mission. This paper highlights significant maneuver activities performed during the last year of the prime mission. Specifically, results of 42 recent maneuvers are presented. Many maneuvers have been skipped, saving fuel and flight team effort. The system has performed more accurately than the pre-launch expectations and requirements. This is in large part why the Cassini-Huygens spacecraft has been navigated with tremendous success during the prime mission.

  12. Object Correlation and Maneuver Detection Using Optimal Control Performance Metrics

    NASA Astrophysics Data System (ADS)

    Holzinger, M.; Scheeres, D.

    2010-09-01

    Object correlation and maneuver detection are persistent problems in space surveillance and space object catalog maintenance. This paper demonstrates the utility of using quadratic trajectory control cost, an analog to the trajectory L2-norm in control, as a distance metric with which to both correlate object tracks and detect maneuvers using Uncorrelated Tracks (UCTs), real-time sensor measurement residuals, and prior state uncertainty. State and measurement uncertainty are incorporated into the computation, and distributions of optimal control usage are computed. Both UCT correlation as well as maneuver detection are demonstrated in several scenarios Potential avenues for future research and contributions are summarized.

  13. Helicopter Pilot Performance for Discrete-maneuver Flight Tasks

    NASA Technical Reports Server (NTRS)

    Heffley, R. K.; Bourne, S. M.; Hindson, W. S.

    1984-01-01

    This paper describes a current study of several basic helicopter flight maneuvers. The data base consists of in-flight measurements from instrumented helicopters using experienced pilots. The analysis technique is simple enough to apply without automatic data processing, and the results can be used to build quantitative matah models of the flight task and some aspects of the pilot control strategy. In addition to describing the performance measurement technqiue, some results are presented which define the aggressiveness and amplitude of maneuvering for several lateral maneuvers including turns and sidesteps.

  14. Early Mission Maneuver Operations for the Deep Space Climate Observatory

    NASA Technical Reports Server (NTRS)

    Roberts, Craig; Case, Sara; Reagoso, John

    2015-01-01

    DSCOVR Lissajous Orbit sized such that orbit track never extends beyond 15 degrees from Earth-Sun line (as seen from Earth). Requiring delta-V maneuvers, control orbit to obey a Solar Exclusion Zone (SEZ) cone of half-angle 4 degrees about the Earth-Sun line. Spacecraft should never be less than 4 degrees from solar center as seen from Earth. Following Lissajous Orbit Insertion (LOI), DSCOVR should be in an opening phase that just skirts the 4-degree SEZ. Maximizes time to the point where a closing Lissajous will require avoidance maneuvers to keep it out of the SEZ. Station keeping maneuvers should take no more than 15 minutes

  15. Constellation Mission Operation Working Group: ESMO Maneuver Planning Process Review

    NASA Technical Reports Server (NTRS)

    Moyer, Eric

    2015-01-01

    The Earth Science Mission Operation (ESMO) Project created an Independent Review Board to review our Conjunction Risk evaluation process and Maneuver Planning Process to identify improvements that safely manages mission conjunction risks, maintains ground track science requirements, and minimizes overall hours expended on High Interest Events (HIE). The Review Board is evaluating the current maneuver process which requires support by multiple groups. In the past year, there have been several changes to the processes although many prior and new concerns exist. This presentation will discuss maneuver process reviews and Board comments, ESMO assessment and path foward, ESMO future plans, recent changes and concerns.

  16. Passive heat exposure induced by hot water leg immersion increased oxyhemoglobin in pre-frontal cortex to preserve oxygenation and did not contribute to impaired cognitive functioning.

    PubMed

    Wijayanto, Titis; Toramoto, Sayo; Tochihara, Yutaka

    2013-07-01

    This study investigated the effects of passive heat exposure on pre-frontal cortex oxygenation and cognitive functioning, specifically to examine whether the change in pre-frontal cortex oxygenation coincided with cognitive functioning during heat exposure. Eleven male students who participated in this study immersed their lower legs to the knees in three different water temperatures, 38 °C, 40 °C, and 42 °C water in an air temperature of 28 º C and 50 % relative humidity for 60 min. After 45 min of leg immersion they performed cognitive functioning tasks assessing their short-term memory while immersing their lower legs. There were higher rectal temperature (P < 0.05) and higher increase of oxyhemoglobin in both left (P < 0.05) and right (P < 0.05) pre-frontal cortex at the final stage of 45-min leg immersion in the 42 °C condition with unaltered tissue oxygenation index among the three conditions (P > 0.05). No statistical difference in cognitive functioning among the three conditions was observed with a higher increase of oxyhemoglobin during the cognitive functioning in the 42 °C condition for the left (P = 0.05) and right (P < 0.05) pre-frontal cortex. The findings of this study suggest, first, passive heat exposure increases oxygen delivery in the pre-frontal cortex to maintain pre-frontal cortex oxygenation; second, there is no evidence of passive heat exposure in cognitive functioning in this study; and third, the greater increases of oxyhemoglobin in the pre-frontal cortex during cognitive functioning at the hottest condition suggests a recruitment of available neural resources or greater effort to maintain the same performance at the same level as when they felt thermally comfortable.

  17. Passive heat exposure induced by hot water leg immersion increased oxyhemoglobin in pre-frontal cortex to preserve oxygenation and did not contribute to impaired cognitive functioning

    NASA Astrophysics Data System (ADS)

    Wijayanto, Titis; Toramoto, Sayo; Tochihara, Yutaka

    2013-07-01

    This study investigated the effects of passive heat exposure on pre-frontal cortex oxygenation and cognitive functioning, specifically to examine whether the change in pre-frontal cortex oxygenation coincided with cognitive functioning during heat exposure. Eleven male students who participated in this study immersed their lower legs to the knees in three different water temperatures, 38 °C, 40 °C, and 42 °C water in an air temperature of 28 º C and 50 % relative humidity for 60 min. After 45 min of leg immersion they performed cognitive functioning tasks assessing their short-term memory while immersing their lower legs. There were higher rectal temperature ( P < 0.05) and higher increase of oxyhemoglobin in both left ( P < 0.05) and right ( P < 0.05) pre-frontal cortex at the final stage of 45-min leg immersion in the 42 °C condition with unaltered tissue oxygenation index among the three conditions ( P > 0.05). No statistical difference in cognitive functioning among the three conditions was observed with a higher increase of oxyhemoglobin during the cognitive functioning in the 42 °C condition for the left ( P = 0.05) and right ( P < 0.05) pre-frontal cortex. The findings of this study suggest, first, passive heat exposure increases oxygen delivery in the pre-frontal cortex to maintain pre-frontal cortex oxygenation; second, there is no evidence of passive heat exposure in cognitive functioning in this study; and third, the greater increases of oxyhemoglobin in the pre-frontal cortex during cognitive functioning at the hottest condition suggests a recruitment of available neural resources or greater effort to maintain the same performance at the same level as when they felt thermally comfortable.

  18. Wakes of Maneuvering Bodies in Stratified Fluids

    NASA Astrophysics Data System (ADS)

    Voropayev, S. I.; Fernando, H. J.

    2007-05-01

    We present the results of experimental/theoretical studies on large momentum eddies generated in late wakes of unsteady moving self-propelled bodies in stratified fluids. The experiments were conducted with scaled submarine model at high Reynolds numbers (50,000), corresponding to the fully turbulent flow regime. Dye visualization and PIV were used for flow diagnostics. When a self-propelled body makes a maneuver, e.g. accelerates, it imparts net momentum on the surrounding fluid. We show that in a stratified fluid this leads to impulsive momentum wakes with large, long-lived coherent vortices in the late flows, which may be used as a signature for identification of submarine wakes in oceanic thermocline. First, we consider dynamics and properties of such wakes in a linearly stratified fluid and present a model that permits to predict the main flow characteristics. Second, we consider wakes in a two layer stratified fluid (analog of the upper ocean) and show that such wakes may penetrate to the water surface; we present a model for this phenomenon and propose criteria for the penetration of wake signatures to the water surface in terms of main governing parameters (signature contrast versus confinement number). Finally, we consider the evolution of such momentum wake eddies in the field of decaying background turbulence, which mimics the oceanic thermocline, and show that for the flow configuration studied the contrast number remains sufficiently large and detectable wake imprints survive for a long period of time. Some pertinent estimates for submarines cruising in the upper ocean are also given. For more details see [1-3]. This study was supported by grant from the Office of Naval Research. 1. Voropayev S.I., Fernando H.J.S., Smirnov S.A. & Morrison R.J. 2006. On surface signatures generated by submersed momentum sources. Phys. Fluids, under revision. 2. Voropayev S.I., Fernando H.J.S. & Morrison R.J. 2006. Dipolar eddies in a stratified turbulent flow. J. Fluid

  19. Non-Toxic Orbiter Maneuvering System (OMS) and Reaction Control System

    NASA Technical Reports Server (NTRS)

    Hurlbert, Eric A.; Nicholson, Leonard S. (Technical Monitor)

    1999-01-01

    NASA is pursuing the technology and advanced development of a non-toxic (NT) orbital maneuvering system (OMS) and reaction control system (RCS) for shuttle upgrades, RLV, and reusable first stages. The primary objectives of the shuttle upgrades program are improved safety, improved reliability, reduced operations time and cost, improved performance or capabilities, and commonality with future space exploration needs. Non-Toxic OMS/RCS offers advantages in each of these categories. A non-toxic OMS/RCS eliminates the ground hazards and the flight safety hazards of the toxic and corrosive propellants. The cost savings for ground operations are over $24M per year for 7 flights, and the savings increase with increasing flight rate up to $44M per year. The OMS/RCS serial processing time is reduced from 65 days to 13 days. The payload capability can be increased up to 5100 Ibms. The non-toxic OMS/RCS also provides improved space station reboost capability up to 20 nautical miles over the current toxic system of 14 nautical miles. A NT OMS/RCS represents a clear advancement in the SOA over MMH/NTO. Liquid oxygen and ethanol are clean burning, high-density propellants that provide a high degree of commonality with other spacecraft subsystems including life support, power, and thermal control, and with future human exploration and development of space missions. The simple and reliable pressure-fed design uses sub-cooled liquid oxygen at 250 to 350 psia, which allows a propellant to remain cryogenic for longer periods of time. The key technologies are thermal insulation and conditioning techniques are used to maintain the sub-cooling. Phase I successfully defined the system architecture, designed an integrated OMS/RCS propellant tank, analyzed the feed system, built and tested the 870 lbf RCS thrusters, and tested the 6000 lbf OMS engine. Phase 11 is currently being planned for the development and test of full-scale prototype of the system in 1999 and 2000

  20. The Impact of Maneuver Failures on the EOS Afternoon Constellation

    NASA Technical Reports Server (NTRS)

    Demarest, Peter

    2002-01-01

    The first four satellites, Aqua, CloudSat, Calipso, and Parasol, in NASA's EOS Afternoon constellation will fly in similar orbits within 4 minutes of each other. This study was undertaken to examine the effect of one or more missions failing to perform a scheduled orbit maintenance maneuver. Tools were developed to rapidly calculate the initial orbital elements for the satellites that established the formation. Baseline maneuver strategies were implemented to maintain the desired spacing of the satellites. Maneuver failures were examined and close approach opportunities were identified. It was found that close-approaches between CloudSat and Calipso could occur in less than one day after a missed maneuver if close coordination between the missions is not achieved.

  1. Deterministic optimal maneuver strategy for multi-target missions

    NASA Technical Reports Server (NTRS)

    Dwivedi, N. P.

    1975-01-01

    This paper presents an optimal strategy for making impulsive correction to a multi-target trajectory by a single maneuver. The concept of an optimal maneuver time is introduced. The choice of suitable weighting functions is explored to enable one to properly translate the subjective desire of mission success into an objective cost function whose minimization yields the optimal strategy. It is shown that a number of strategies previously formulated are derivable from one general expression. A number of other interesting properties of the optimal strategy are described. Numerical results are presented for a typical two-target mission. It is shown that the strategy formulated is optimal. For some perturbations, there exists an optimal maneuver time different from the time of initiation of the perturbation. That is, the physical properties of the trajectory can be exploited to select the optimal time of making a corrective maneuver.

  2. Investigation of Dynamic Flight Maneuvers With an Iced Tailplane

    NASA Technical Reports Server (NTRS)

    VanZante, Judith Foss; Ratvasky, Thomas P.

    1999-01-01

    A detailed analysis of two of the dynamic maneuvers, the pushover and elevator doublet, from the NASA/FAA Tailplane Icing Program are discussed. For this series of flight tests, artificial ice shapes were attached to the leading edge of the horizontal stabilizer of the NASA Lewis Research Center icing aircraft, a DHC-6 Twin Otter. The purpose of these tests was to learn more about ice-contaminated tailplane stall (ICTS), the known cause of 16 accidents resulting in 139 fatalities. The pushover has been employed by the FAA, JAA and Transport Canada for tailplane icing certification. This research analyzes the pushover and reports on the maneuver performance degradation due to ice shape severity and flap deflection. A repeatability analysis suggests tolerances for meeting the required targets of the maneuver. A second maneuver, the elevator doublet, is also studied.

  3. Rendezvous radar for the orbital maneuvering vehicle

    NASA Technical Reports Server (NTRS)

    Locke, John W.; Olds, Keith; Parks, Howard

    1991-01-01

    This paper describes the development of the Rendezvous Radar Set (RRS) for the Orbital Maneuvering Vehicle (OMV) for the National Aeronautics and Space Administration (NASA). The RRS was to be used to locate, and then provide vectoring information to, target satellites (or Shuttle or Space Station) to aid the OMV in making a minimum-fuel-consumption approach and rendezvous. The RRS design is that of an X-Band, all solid-state, monopulse tracking, frequency hopping, pulse-Doppler radar system. The development of the radar was terminated when the OMV prime contract to TRW was terminated by NASA. At the time of the termination, the development was in the circuit design stage. The system design was virtually completed, the PDR had been held. The RRS design was based on Motorola's experiences, both in the design and production of radar systems for the US Army and in the design and production of hi-rel communications systems for NASA space programs. Experience in these fields was combined with the latest digital signal processor and micro-processor technology to design a light-weight, low-power, spaceborne radar. The antenna and antenna positioner (gimbals) technology developed for the RRS is now being used in the satellite-to-satellite communication link design for Motorola's Iridium telecommunications system.

  4. Augmentation of maneuver performance by spanwise blowing

    NASA Technical Reports Server (NTRS)

    Erickson, G. E.; Campbell, J. F.

    1977-01-01

    A generalized wind tunnel model was tested to investigate new component concepts utilizing spanwise blowing to provide improved maneuver characteristics for advanced fighter aircraft. Primary emphasis was placed on high angle of attack performance, stability, and control at subsonic speeds. Spanwise blowing on a 44 deg swept trapezoidal wing resulted in leading edge vortex enhancement with subsequent large vortex-induced lift increments and drag polar improvements at the higher angles of attack. Small deflections of a leading edge flap delayed these lift and drag benefits to higher angles of attack. In addition, blowing was more effective at higher Mach numbers. Spanwise blowing in conjunction with a deflected trailing edge flap resulted in lift and drag benefits that exceeded the summation of the effects of each high lift device acting alone. Asymmetric blowing was an effective lateral control device at the higher angles of attack. Spanwise blowing on the wing reduced horizontal tail loading and improved the lateral-directional stability characteristics of a wing-horizontal tail-vertical tail configuration.

  5. An Immunized Aircraft Maneuver Selection System

    NASA Technical Reports Server (NTRS)

    Karr, Charles L.

    2003-01-01

    The objective of this project, as stated in the original proposal, was to develop an immunized aircraft maneuver selection (IAMS) system. The IAMS system was to be composed of computational and informational building blocks that resemble structures in natural immune systems. The ultimate goal of the project was to develop a software package that could be flight tested on aircraft models. This report describes the work performed in the first year of what was to have been a two year project. This report also describes efforts that would have been made in the final year to have completed the project, had it been continued for the final year. After introductory material is provided in Section 2, the end-of-year-one status of the effort is discussed in Section 3. The remainder of the report provides an accounting of first year efforts. Section 4 provides background information on natural immune systems while Section 5 describes a generic ar&itecture developed for use in the IAMS. Section 6 describes the application of the architecture to a system identification problem. Finally, Section 7 describes steps necessary for completing the project.

  6. Improvements to the adaptive maneuvering logic program

    NASA Technical Reports Server (NTRS)

    Burgin, George H.

    1986-01-01

    The Adaptive Maneuvering Logic (AML) computer program simulates close-in, one-on-one air-to-air combat between two fighter aircraft. Three important improvements are described. First, the previously available versions of AML were examined for their suitability as a baseline program. The selected program was then revised to eliminate some programming bugs which were uncovered over the years. A listing of this baseline program is included. Second, the equations governing the motion of the aircraft were completely revised. This resulted in a model with substantially higher fidelity than the original equations of motion provided. It also completely eliminated the over-the-top problem, which occurred in the older versions when the AML-driven aircraft attempted a vertical or near vertical loop. Third, the requirements for a versatile generic, yet realistic, aircraft model were studied and implemented in the program. The report contains detailed tables which make the generic aircraft to be either a modern, high performance aircraft, an older high performance aircraft, or a previous generation jet fighter.

  7. Astronaut Alan Bean flies the Astronaut Maneuvering Equipment

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Alan L. Bean, Skylab 3 commander, flies the M509 Astronaut Maneuvering Equipment in the foreward dome area of the Orbital Workshop (OWS) on the space station cluster in Earth orbit. Bean is strapped in to the back-mounted, hand-controlled Automatically Stabilized Maneuvering Unit (ASMU). This ASMU exerperiment is being done in shirt sleeves. The dome area where the experiment is conducted is about 22 feet in diameter and 19 feet from top to bottom.

  8. Astronaut Alan Bean flies the Astronaut Maneuvering Equipment

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Alan L. Bean, Skylab 3 commander, flies the M509 Astronaut Maneuvering Equipment in the forward dome area of the Orbital Workshop (OWS) on the space station cluster in Earth orbit. Bean is strapped in to the back-mounted, hand-controlled Automatically Stabilized Maneuvering Unit (ASMU). This ASMU exerperiment is being done in shirt sleeves. The dome area where the experiment is conducted is about 22 feet in diameter and 19 feet from top to bottom.

  9. Spontaneous splenic rupture during Pringle maneuver in liver surgery.

    PubMed

    van Buijtenen, Jesse M; Lamme, Bas; Hesselink, Erik J

    2010-06-27

    During liver resection clamping of the hepato-duodenal ligament (the Pringle maneuver) is performed to reduce intraoperative blood-loss. During this maneuver acute portal hypertension may lead to spontaneous splenic rupture requiring rapid splenectomy in order to control blood loss. We present 2 case of patients with hemorrhage from the spleen during clamping for liver surgery. A review of the literature with an emphasis on the pathophysiology of splenic hemorrhage is presented. PMID:21161004

  10. Reducing Cytoplasmic Polyamine Oxidase Activity in Arabidopsis Increases Salt and Drought Tolerance by Reducing Reactive Oxygen Species Production and Increasing Defense Gene Expression

    PubMed Central

    Sagor, G. H. M.; Zhang, Siyuan; Kojima, Seiji; Simm, Stefan; Berberich, Thomas; Kusano, Tomonobu

    2016-01-01

    The link between polyamine oxidases (PAOs), which function in polyamine catabolism, and stress responses remains elusive. Here, we address this issue using Arabidopsis pao mutants in which the expression of the five PAO genes is knocked-out or knocked-down. As the five single pao mutants and wild type (WT) showed similar response to salt stress, we tried to generate the mutants that have either the cytoplasmic PAO pathway (pao1 pao5) or the peroxisomal PAO pathway (pao2 pao3 pao4) silenced. However, the latter triple mutant was not obtained. Thus, in this study, we used two double mutants, pao1 pao5 and pao2 pao4. Of interest, pao1 pao5 mutant was NaCl- and drought-tolerant, whereas pao2 pao4 showed similar sensitivity to those stresses as WT. To reveal the underlying mechanism of salt tolerance, further analyses were performed. Na uptake of the mutant (pao1 pao5) decreased to 75% of WT. PAO activity of the mutant was reduced to 62% of WT. The content of reactive oxygen species (ROS) such as hydrogen peroxide, a reaction product of PAO action, and superoxide anion in the mutant became 81 and 72% of the levels in WT upon salt treatment. The mutant contained 2.8-fold higher thermospermine compared to WT. Moreover, the mutant induced the genes of salt overly sensitive-, abscisic acid (ABA)-dependent- and ABA-independent- pathways more strongly than WT upon salt treatment. The results suggest that the Arabidopsis plant silencing cytoplasmic PAOs shows salinity tolerance by reducing ROS production and strongly inducing subsets of stress-responsive genes under stress conditions. PMID:26973665

  11. Maneuver Design and Calibration for the Genesis Spacecraft

    NASA Technical Reports Server (NTRS)

    Williams, Kenneth E.; Hong, Philip E.; Zietz, Richard P.; Han, Don

    2000-01-01

    Genesis is the fifth mission selected as part of NASA's Discovery Program. The objective of Genesis is to collect solar wind samples for a period of approximately two years while in a halo orbit about the Earth-Sun L I point. At the end of this period, the samples are to be returned to a specific recovery point on the Earth for subsequent analysis. This goal has never been attempted before and presents a formidable challenge in terms of mission design and operations, particularly planning and execution of propulsive maneuvers. To achieve a level of cost-effectiveness consistent with a Discovery-class mission, the Genesis spacecraft design was adapted to the maximum extent possible from designs used on earlier missions, such as Mars Global Surveyor (MGS) and Stardust, another sample collection mission. The spacecraft design for Genesis is shown. Spin stabilization was chosen for attitude control, in lieu of three-axis stabilization, with neither reaction wheels nor accelerometers included. This precludes closed-loop control of propulsive maneuvers and implies that any attitude changes, including spin changes and precessions, will behave like translational propulsive maneuvers and affect the spacecraft trajectory. Moreover, to minimize contamination risk to the samples collected, all thrusters were placed on the side opposite the sample collection canister. The orientation and characteristics of thrusters are indicated. For large maneuvers (>2.5 m/s), two 5 lbf thrusters will be used for delta v, with precession to the burn attitude, followed by spin-up from 1.6 to 10 rpm before the burn and spin down to 1.6 rpm afterwards, then precession back to the original spin attitude. For small maneuvers (<2.5 m/s), no spin change is needed and four 0.2 lbf thrusters are used for Av. Single or double 360 deg. precession changes are required whenever the desired delta v falls inside the two-way turn circle (about 0.4 m/s) based on the mass properties, spin rate and lever arm

  12. Maintaining Aura's Orbit Requirements Under New Maneuver Operations

    NASA Technical Reports Server (NTRS)

    Johnson, Megan; Petersen, Jeremy D.

    2014-01-01

    The Earth Observing System (EOS) Afternoon Constellation consists of five member missions (GCOM-W1, Aqua, CALIPSO, CloudSat, and Aura), each of which maintain a frozen, sun-synchronous orbit with a 16-day repeating ground track that follows the Worldwide Reference System-2 (WRS-2). Under nominal science operations for Aura, the propulsion system is oriented such that the resultant thrust vector is aligned 13.493 degrees away from the velocity vector along the yaw axis. When performing orbit maintenance maneuvers, the spacecraft performs a yaw slew to align the thrust vector in the appropriate direction. A new Drag Make Up (DMU) maneuver operations scheme has been implemented for Aura alleviating the need for the 13.493 degree yaw slew. The focus of this investigation is to assess the impact that no-slew DMU maneuver operations will have on Auras Mean Local Time (MLT) which drives the required along track separation between Aura and the constellation members, as well as Auras frozen orbit properties, eccentricity and argument of perigee. Seven maneuver strategies were analyzed to determine the best operational approach. A mirror pole strategy, with maneuvers alternating at the North and South poles, was implemented operationally to minimize impact to the MLT. Additional analysis determined that the mirror pole strategy could be further modified to include frozen orbit maneuvers and thus maintain both MLT and the frozen orbit properties under no-slew operations

  13. IMAM algorithm for tracking maneuvering targets in clutter

    NASA Astrophysics Data System (ADS)

    Watson, Gregory A.

    1996-05-01

    Target tracking in clutter is difficult because there can be several contact-to-track associations for a given track update. The nearest neighbor approach is traditionally used but probabilistic methods, such as probabilistic data association (PDA), have since proved more capable. Tracks are also lost during maneuvers and the interacting multiple model (IMM) algorithm has been demonstrated to be effective at tracking maneuvering targets by responding to different target modes. By combining the IMM and PDA, the resulting algorithm responds to target maneuvers and is effective in clutter. The interacting multiple bias model (IMBM) algorithm is also an effective technique when tracking maneuvering targets but considers the target acceleration a system bias. The bias is estimated in an IMM algorithm framework and then used to compensate a constant velocity filter estimate. The integrated PDA filter will be incorporated into the IMBM algorithm and applied to tracking maneuvering targets in clutter. A performance comparison of IMM and IMBM techniques for tracking maneuvering targets in clutter will also be presented.

  14. Optimal diving maneuver strategy considering guidance accuracy for hypersonic vehicle

    NASA Astrophysics Data System (ADS)

    Zhu, Jianwen; Liu, Luhua; Tang, Guojian; Bao, Weimin

    2014-11-01

    An optimal maneuver strategy considering terminal guidance accuracy for hypersonic vehicle in dive phase is investigated in this paper. First, it derives the complete three-dimensional nonlinear coupled motion equation without any approximations based on diving relative motion relationship directly, and converts it into linear decoupled state space equation with the same relative degree by feedback linearization. Second, the diving guidance law is designed based on the decoupled equation to meet the terminal impact point and falling angle constraints. In order to further improve the interception capability, it constructs maneuver control model through adding maneuver control item to the guidance law. Then, an integrated performance index consisting of maximum line-of-sight angle rate and minimum energy consumption is designed, and optimal control is employed to obtain optimal maneuver strategy when the encounter time is determined and undetermined, respectively. Furthermore, the performance index and suboptimal strategy are reconstructed to deal with the control capability constraint and the serous influence on terminal guidance accuracy caused by maneuvering flight. Finally, the approach is tested using the Common Aero Vehicle-H model. Simulation results demonstrate that the proposed strategy can achieve high precision guidance and effective maneuver at the same time, and the indices are also optimized.

  15. ICI D7114 a novel selective beta-adrenoceptor agonist selectively stimulates brown fat and increases whole-body oxygen consumption.

    PubMed

    Holloway, B R; Howe, R; Rao, B S; Stribling, D; Mayers, R M; Briscoe, M G; Jackson, J M

    1991-09-01

    1. ICI D7114 is a novel, beta-adrenoceptor agonist which stimulates whole body oxygen consumption in conscious rats, cats and dogs and brown adipose tissue (BAT) activity in conscious rats. Treatment of rats with ICI D7114 stimulated oxygen consumption (ED50, 0.04 mg kg-1, p.o.) and BAT mitochondrial guanosine diphosphate (GDP)-binding (ED50, 0.15 mg kg-1, p.o.) with no chronotropic effects on the heart at these doses. 2. Reference beta-adrenoceptor agonists, isoprenaline and clenbuterol, also stimulated oxygen consumption and BAT activity but were less selective because they also produced effects on heart rate at these doses. 3. Treatment of conscious rats with ICI D7114 did not attenuate the chronotropic effects on the heart of a subsequent isoprenaline challenge. 4. Administration of ICI D7114 or of its acid metabolite had no effect in a cat soleus muscle model of tremor or on blood potassium levels in the conscious dog, indicating lack of effects at beta 2-adrenoceptors. 5. The results indicate that ICI D7114 may have activity at atypical beta-adrenoceptors in brown adipose tissue leading to increased whole body oxygen consumption. PMID:1686210

  16. ICI D7114 a novel selective beta-adrenoceptor agonist selectively stimulates brown fat and increases whole-body oxygen consumption.

    PubMed Central

    Holloway, B. R.; Howe, R.; Rao, B. S.; Stribling, D.; Mayers, R. M.; Briscoe, M. G.; Jackson, J. M.

    1991-01-01

    1. ICI D7114 is a novel, beta-adrenoceptor agonist which stimulates whole body oxygen consumption in conscious rats, cats and dogs and brown adipose tissue (BAT) activity in conscious rats. Treatment of rats with ICI D7114 stimulated oxygen consumption (ED50, 0.04 mg kg-1, p.o.) and BAT mitochondrial guanosine diphosphate (GDP)-binding (ED50, 0.15 mg kg-1, p.o.) with no chronotropic effects on the heart at these doses. 2. Reference beta-adrenoceptor agonists, isoprenaline and clenbuterol, also stimulated oxygen consumption and BAT activity but were less selective because they also produced effects on heart rate at these doses. 3. Treatment of conscious rats with ICI D7114 did not attenuate the chronotropic effects on the heart of a subsequent isoprenaline challenge. 4. Administration of ICI D7114 or of its acid metabolite had no effect in a cat soleus muscle model of tremor or on blood potassium levels in the conscious dog, indicating lack of effects at beta 2-adrenoceptors. 5. The results indicate that ICI D7114 may have activity at atypical beta-adrenoceptors in brown adipose tissue leading to increased whole body oxygen consumption. PMID:1686210

  17. Critical closing pressure explains cerebral hemodynamics during the Valsalva maneuver.

    PubMed

    Dawson, S L; Panerai, R B; Potter, J F

    1999-02-01

    The Valsalva maneuver (VM), a voluntary increase in intrathoracic pressure of approximately 40 mmHg, has been used to examine cerebral autoregulation (CA). During phase IV of the VM there are pronounced changes in mean arterial blood pressure (MABP), pulse interval, and cerebral blood flow (CBF), but the changes in CBF are of a much greater magnitude than those seen in MABP, a finding to date attributed to either a delay in activation of the CA mechanism or the inability of this mechanism to cope with the size and speed of the blood pressure changes involved. These changes in CBF also precede those in MABP, a pattern of events not explained by the physiological process of CA. Measurements of CBF velocity (transcranial Doppler) and MABP (Finapres) were performed in 53 healthy volunteers (aged 31-80 yr). By calculating beat-to-beat values of critical closing pressure (CCP) during the VM, we have found that this parameter suddenly drops at the start of phase IV, providing a coherent explanation for the large increase in CBF. If CCP is included in the estimation of cerebrovascular resistance, a temporal pattern more consistent with an autoregulatory response to the MABP overshoot is also found. CCP is intricately involved in the control of CBF during the VM and should be considered in the assessment of CA. PMID:9931207

  18. Recovery of halo orbit missions in case of contingent station-keeping maneuver delay

    NASA Astrophysics Data System (ADS)

    Shirobokov, Maksim; Trofimov, Sergey; Ovchinnikov, Mikhail

    2016-11-01

    This paper investigates a recovery strategy for halo orbit missions in case of contingent station-keeping maneuver delay. It is assumed that (1) the delay is temporal, and the spacecraft control becomes available after the delay, (2) the thruster is not producing thrust during the delay. The idea behind the recovery strategy is to deliver the spacecraft into the "cheapest-to-get" halo orbit rather than into the reference one. This approach reduces the transfer costs and saves fuel that can be used for future station-keeping maneuvers, thereby increasing the mission lifetime. Monte Carlo trials are used to estimate the savings and their scattering for each delay time. Families of halo orbits around the Sun-Earth L1 /L2 points and the Earth-Moon L1 /L2 points are considered.

  19. Purging using the Heimlich maneuver among children and adolescents with eating disorders.

    PubMed

    Boachie, Ahmed; Kusi Appiah, Edigna; Jubin, Michelle; Jasper, Karin

    2015-09-01

    This case report describes five independent cases of children and adolescents assessed for eating disorders who disclosed using the Heimlich maneuver as a purging technique. The maneuver is meant to be used only in life or death situations, likely once or less in any person's lifetime. A child or adolescent with an eating disorder may be using it to self-induce vomiting on a daily basis, increasing the risk of complications, including potential damage to major organs of the body. Asking patients who purge to elaborate on the methods with which they purge can provide clinicians with fuller information, improving their ability to select appropriate medical tests and interventions. Thorough investigations of physical complaints during the patient assessment may be warranted, including examining patients for possible rib fractures, hemorrhages, perforations of the hollow viscous, and other forms of blunt abdominal traumas. PMID:25846517

  20. An investigation of the use of a propulsive wing/canard concept for improved maneuvering

    NASA Technical Reports Server (NTRS)

    Stewart, V. R.

    1981-01-01

    The propulsive wing concept is an extension of the flap boundary layer control utilized on several aircraft configurations. Several studies have been made regarding the benefits of the propulsive wing in STOL operation. However, the propulsive wing/canard provides performance benefits also in areas other than STOL. It is expected to improve the maneuvering capability by providing reduced drag at high lift coefficients without appreciably affecting the low lift drag. An increase in the buffet free load factor can also be expected with the blown wing and canard. Attention is given to a program to investigate the wing/canard at maneuvering conditions, and tests at ranges of blowing coefficients equivalent to STOL operation.

  1. Purging using the Heimlich maneuver among children and adolescents with eating disorders.

    PubMed

    Boachie, Ahmed; Kusi Appiah, Edigna; Jubin, Michelle; Jasper, Karin

    2015-09-01

    This case report describes five independent cases of children and adolescents assessed for eating disorders who disclosed using the Heimlich maneuver as a purging technique. The maneuver is meant to be used only in life or death situations, likely once or less in any person's lifetime. A child or adolescent with an eating disorder may be using it to self-induce vomiting on a daily basis, increasing the risk of complications, including potential damage to major organs of the body. Asking patients who purge to elaborate on the methods with which they purge can provide clinicians with fuller information, improving their ability to select appropriate medical tests and interventions. Thorough investigations of physical complaints during the patient assessment may be warranted, including examining patients for possible rib fractures, hemorrhages, perforations of the hollow viscous, and other forms of blunt abdominal traumas.

  2. TCDD decreases ATP levels and increases reactive oxygen production through changes in mitochondrial F F{sub 1}-ATP synthase and ubiquinone

    SciTech Connect

    Shertzer, Howard G. . E-mail: shertzhg@ucmail.uc.edu; Genter, Mary Beth; Shen, Dongxiao; Nebert, Daniel W.; Chen, Ying; Dalton, Timothy P.

    2006-12-15

    Mitochondria generate ATP and participate in signal transduction and cellular pathology and/or cell death. TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) decreases hepatic ATP levels and generates mitochondrial oxidative DNA damage, which is exacerbated by increasing mitochondrial glutathione redox state and by inner membrane hyperpolarization. This study identifies mitochondrial targets of TCDD that initiate and sustain reactive oxygen production and decreased ATP levels. One week after treating mice with TCDD, liver ubiquinone (Q) levels were significantly decreased, while rates of succinoxidase and Q-cytochrome c oxidoreductase activities were increased. However, the expected increase in Q reduction state following TCDD treatment did not occur; instead, Q was more oxidized. These results could be explained by an ATP synthase defect, a premise supported by the unusual finding that TCDD lowers ATP/O ratios without concomitant changes in respiratory control ratios. Such results suggest either a futile cycle in ATP synthesis, or hydrolysis of newly synthesized ATP prior to release. The TCDD-mediated decrease in Q, concomitant with an increase in respiration, increases complex 3 redox cycling. This acts in concert with glutathione to increase membrane potential and reactive oxygen production. The proposed defect in ATP synthase explains both the greater respiratory rates and the lower tissue ATP levels.

  3. Aluminum induces neurodegeneration and its toxicity arises from increased iron accumulation and reactive oxygen species (ROS) production.

    PubMed

    Wu, Zhihao; Du, Yumei; Xue, Hua; Wu, Yongsheng; Zhou, Bing

    2012-01-01

    The neurotoxicity of aluminum (Al) - the most abundant metal element on earth - has been known for years. However, the mechanism of Al-induced neurodegeneration and its relationship to Alzheimer's disease are still controversial. In particular, in vivo functional data are lacking. In a Drosophila model with chronic dietary Al overloading, general neurodegeneration and several behavioral changes were observed. Al-induced neurodegeneration is independent of β-amyloid or tau-associated toxicity, suggesting they act in different molecular pathways. Interestingly, Drosophila frataxin (dfh), which causes Friedreich's ataxia if mutated in humans, displayed an interacting effect with Al, suggesting Friedreich's ataxia patients might be more susceptible to Al toxicity. Al-treated flies accumulated large amount of iron and reactive oxygen species (ROS), and exhibited elevated SOD2 activity. Genetic and pharmacological efforts to reduce ROS or chelate excess Fe significantly mitigated Al toxicity. Our results indicate that Al toxicity is mediated through ROS production and iron accumulation and suggest a remedial route to reduce toxicity due to Al exposure.

  4. Non-Oxygenated Sesquiterpenes in the Essential Oil of Copaifera langsdorffii Desf. Increase during the Day in the Dry Season

    PubMed Central

    de Almeida, Luiz Fernando Rolim; Portella, Roberto de Oliveira; Bufalo, Jennifer; Marques, Márcia Ortiz Mayo; Facanali, Roselaine; Frei, Fernando

    2016-01-01

    The present study aimed to evaluate the effect of seasonal and diurnal events on the chemical profile of the essential oil obtained from the leaves of Copaifera langsdorffii Desf. This study was performed in a Brazilian savanna named Cerrado. We identified the best harvesting period for obtaining the highest amount of compounds used for commercial and industrial purposes. The chemical profile of the essential oils was evaluated by GC-FID and GC-MS, and the results were assessed through multivariate analyses. The data showed that the time of day and seasonal variations affect the quality of the essential oil obtained. Leaves harvested at the end of the day (5:00 pm) in the dry season resulted in richer essential oils with higher amounts of non-oxygenated sesquiterpenes. To the best of our knowledge, environmental conditions induce metabolic responses in the leaves of C. langsdorffii, which changes the patterns of sesquiterpene production. Therefore, these factors need to be considered to obtain better concentrations of bioactive compounds for pharmacological studies. PMID:26886431

  5. Non-Oxygenated Sesquiterpenes in the Essential Oil of Copaifera langsdorffii Desf. Increase during the Day in the Dry Season.

    PubMed

    de Almeida, Luiz Fernando Rolim; Portella, Roberto de Oliveira; Bufalo, Jennifer; Marques, Márcia Ortiz Mayo; Facanali, Roselaine; Frei, Fernando

    2016-01-01

    The present study aimed to evaluate the effect of seasonal and diurnal events on the chemical profile of the essential oil obtained from the leaves of Copaifera langsdorffii Desf. This study was performed in a Brazilian savanna named Cerrado. We identified the best harvesting period for obtaining the highest amount of compounds used for commercial and industrial purposes. The chemical profile of the essential oils was evaluated by GC-FID and GC-MS, and the results were assessed through multivariate analyses. The data showed that the time of day and seasonal variations affect the quality of the essential oil obtained. Leaves harvested at the end of the day (5:00 pm) in the dry season resulted in richer essential oils with higher amounts of non-oxygenated sesquiterpenes. To the best of our knowledge, environmental conditions induce metabolic responses in the leaves of C. langsdorffii, which changes the patterns of sesquiterpene production. Therefore, these factors need to be considered to obtain better concentrations of bioactive compounds for pharmacological studies.

  6. Flight-motor-driven respiratory airflow increases tracheal oxygen to nearly atmospheric level in blowflies (Calliphora vicina).

    PubMed

    Wasserthal, Lutz T

    2015-07-01

    It is widely accepted that an efficient oxygen supply and removal of CO2 in small flying insects are sufficiently performed by diffusion with open spiracles. This paper shows that in the tethered flying blowfly, gas exchange occurs by autoventilation and unidirectional airflow. The air is inspired through the mesothoracic spiracles (Sp1) during the downstroke of the wings and is expired through the metathoracic spiracles (Sp2) during the upstroke. This directed airflow through the thoracic tracheal system was documented by pre-atrial pressure measurements at the Sp1 and Sp2, revealing a sub-atmospheric mean pressure at the Sp1 and an over-atmospheric mean pressure at the Sp2. In the mesothoracic air sacs, the mean pressure is sub-atmospheric, conditioned by the only slightly open spiracles. In a split flow-through chamber experiment, the CO2 released through the Sp2 confirmed this unidirectional respiratory gas flow, implicating an inner tracheal valve. In the thoracic tracheal system, the PO2  during flight exceeds the high resting PO2  by 1-2 kPa, reaching nearly atmospheric values. In the abdominal large air sacs, the PO2  drops during flight, probably due to the accumulation of CO2. Periodic heartbeat reversals continue during flight, with a higher period frequency than at rest, supporting the transport of CO2 via the haemolymph towards the metathoracic tracheae and abdominal air sacs. PMID:26202777

  7. An Overview of Suomi NPP VIIRS Calibration Maneuvers

    NASA Technical Reports Server (NTRS)

    Butler, James J.; Xiong, Xiaoxiong; Barnes, Robert A.; Patt, Frederick S.; Sun, Junqiang; Chiang, Kwofu

    2012-01-01

    The first Visible Infrared Imager Radiometer Suite (VIIRS) instrument was successfully launched on-board the Suomi National Polar-orbiting Partnership (SNPP) spacecraft on October 28, 2011. Suomi NPP VIIRS observations are made in 22 spectral bands, from the visible (VIS) to the long-wave infrared (LWIR), and are used to produce 22 Environmental Data Records (EDRs) with a broad range of scientific applications. The quality of these VIIRS EDRs strongly depends on the quality of its calibrated and geo-located Sensor Date Records (SDRs). Built with a strong heritage to the NASA's EOS MODerate resolution Imaging Spectroradiometer (MODIS) instrument, the VIIRS is calibrated on-orbit using a similar set of on-board calibrators (OBC), including a solar diffuser (SD) and solar diffuser stability monitor (SDSM) system for the reflective solar bands (RSB) and a blackbody (BB) for the thermal emissive bands (TEB). On-orbit maneuvers of the SNPP spacecraft provide additional calibration and characterization data from the VIIRS instrument which cannot be obtained pre-launch and are required to produce the highest quality SDRs. These include multi-orbit yaw maneuvers for the characterization of SD and SDSM screen transmission, quasi-monthly roll maneuvers to acquire lunar observations to track sensor degradation in the visible through shortwave infrared, and a driven pitch-over maneuver to acquire multiple scans of deep space to determine TEB response versus scan angle (RVS). This paper pro-vides an overview of these three SNPP calibration maneuvers. Discussions are focused on their potential calibration and science benefits, pre-launch planning activities, and on-orbit scheduling and implementation strategies. Results from calibration maneuvers performed during the Intensive Calibration and Validation (ICV) period for the VIIRS sensor are illustrated. Also presented in this paper are lessons learned regarding the implementation of calibration spacecraft maneuvers on follow

  8. Essential role of SBP-1 activation in oxygen deprivation induced lipid accumulation and increase in body width/length ratio in Caenorhabditis elegans.

    PubMed

    Taghibiglou, Changiz; Martin, Henry G S; Rose, Jacqueline K; Ivanova, Nadia; Lin, Conny H C; Lau, H Lee; Rai, Susan; Wang, Yu Tian; Rankin, Catharine H

    2009-02-18

    Epidemiological evidence suggests a link between chronic oxygen starvation and fat accumulation/obesity, however the underlying mechanism remains unclear. Using Caenorhabditis elegans we found extended oxygen deprivation resulted in activation of SBP-1, the worm homologue of SREBP1, a transcription factor important in maintaining lipid homeostasis. SBP-1 knockdown prevented hypoxia-induced fat accumulation and the associated increase in worm width/length ratio, demonstrating that SBP-1/SREBP1 plays an essential role in hypoxia-induced lipid accumulation and body shape alteration. This study provides the first evidence suggesting that activation of SREBP1 may be a critical pathogenic factor contributing to chronic hypoxia associated excessive fat accumulation/obesity in humans.

  9. Hydroxylated polychlorinated biphenyls increase reactive oxygen species formation and induce cell death in cultured cerebellar granule cells

    SciTech Connect

    Dreiem, Anne Rykken, Sidsel; Lehmler, Hans-Joachim; Robertson, Larry W.; Fonnum, Frode

    2009-10-15

    Polychlorinated biphenyls (PCBs) are persistent organic pollutants that bioaccumulate in the body, however, they can be metabolized to more water-soluble products. Although they are more readily excreted than the parent compounds, some of the metabolites are still hydrophobic and may be more available to target tissues, such as the brain. They can also cross the placenta and reach a developing foetus. Much less is known about the toxicity of PCB metabolites than about the parent compounds. In the present study, we have investigated the effects of eight hydroxylated (OH) PCB congeners (2'-OH PCB 3, 4-OH PCB 14, 4-OH PCB 34, 4'-OH PCB 35, 4-OH PCB 36, 4'-OH PCB 36, 4-OH PCB 39, and 4'-OH PCB 68) on reactive oxygen species (ROS) formation and cell viability in rat cerebellar granule cells. We found that, similar to their parent compounds, OH-PCBs are potent ROS inducers with potency 4-OH PCB 14 < 4-OH PCB 36 < 4-OH PCB 34 < 4'-OH PCB 36 < 4'-OH PCB 68 < 4-OH PCB 39 < 4'-OH PCB 35. 4-OH PCB 36 was the most potent cell death inducer, and caused apoptotic or necrotic morphology depending on concentration. Inhibition of ERK1/2 kinase with U0126 reduced both cell death and ROS formation, suggesting that ERK1/2 activation is involved in OH-PCB toxicity. The results indicate that the hydroxylation of PCBs may not constitute a detoxification reaction. Since OH-PCBs like their parent compounds are retained in the body and may be more widely distributed to sensitive tissues, it is important that not only the levels of the parent compounds but also the levels of their metabolites are taken into account during risk assessment of PCBs and related compounds.

  10. MEMS Reaction Control and Maneuvering for Picosat Beyond LEO

    NASA Technical Reports Server (NTRS)

    Alexeenko, Alina

    2016-01-01

    The MEMS Reaction Control and Maneuvering for Picosat Beyond LEO project will further develop a multi-functional small satellite technology for low-power attitude control, or orientation, of picosatellites beyond low Earth orbit (LEO). The Film-Evaporation MEMS Tunable Array (FEMTA) concept initially developed in 2013, is a thermal valving system which utilizes capillary forces in a microchannel to offset internal pressures in a bulk fluid. The local vapor pressure is increased by resistive film heating until it exceeds meniscus strength in a nozzle which induces vacuum boiling and provides a stagnation pressure equal to vapor pressure at that point which is used for propulsion. Interplanetary CubeSats can utilize FEMTA for high slew rate attitude corrections in addition to desaturating reaction wheels. The FEMTA in cooling mode can be used for thermal control during high-power communication events, which are likely to accompany the attitude correction. Current small satellite propulsion options are limited to orbit correction whereas picosatellites are lacking attitude control thrusters. The available attitude control systems are either quickly saturated reaction wheels or movable high drag surfaces with long response times.

  11. Orbital maneuvers around irregular shaped bodies

    NASA Astrophysics Data System (ADS)

    Venditti, Flaviane; Rocco, E. M.; Almeida Prado, A. B.

    2013-05-01

    Abstract (2,250 Maximum Characters): In the solar system there are many small bodies called asteroids. The large majority of these bodies are located in the asteroid belt, between the orbits of the planets Mars and Jupiter. The Near- Earth Objects, or NEOs, are objects with perihelion below 1.3AU, which include comets and asteroids. The NEOs are considered to have orbits passing close to the Earth’s orbit and, in the case of asteroids, are called Near-Earth Asteroids (NEAs). Among the NEAs there are bodies considered potentially hazardous asteroids (PHAs), whose minimum orbit intersection distance with Earth is 0.05AU and that have absolute magnitude (H) of 22, which would mean an asteroid of at least 110-240 meters, depending on its albedo. One of the major characteristic of the asteroids is the irregular shape, causing the dynamics of orbits around these bodies to be different from a spherical shaped one. The fact that an object is not spherical generates a perturbation on the gravitational field. The disturbing force can be determined considering the shape of the specific body. A satellite orbiting this body would suffer the effects of this perturbation, but knowing the disturbing force, it’s possible to correct and control the orbit according to the desired mission. The polyhedron method is a traditional way to model an asteroid by dividing the object into smaller parts. The data used on this work are composed by a combination of triangular faces. The total disturbing force is a sum of the force on each piece of the model. Therefore, after the simulations are obtained, it’s possible to apply the desired corrections of the perturbation using continuous low thrust in closed loop, making it possible to perform maneuvers near these bodies. One of the important applications of the study shown above is in the ASTER mission, that is under study by INPE and several other Brazilian academic institutions, which goal is to send a spacecraft to an asteroid and then

  12. Investigation of piloting aids for manual control of hypersonic maneuvers

    NASA Technical Reports Server (NTRS)

    Raney, David L.; Phillips, Michael R.; Person, Lee H., Jr.

    1995-01-01

    An investigation of piloting aids designed to provide precise maneuver control for an air-breathing hypersonic vehicle is described. Stringent constraints and nonintuitive high-speed flight effects associated with maneuvering in the hypersonic regime raise the question of whether manual control of such a vehicle should even be considered. The objectives of this research were to determine the extent of manual control that is desirable for a vehicle maneuvering in this regime and to identify the form of aids that must be supplied to the pilot to make such control feasible. A piloted real-time motion-based simulation of a hypersonic vehicle concept was used for this study, and the investigation focused on a single representative cruise turn maneuver. Piloting aids, which consisted of an auto throttle, throttle director, autopilot, flight director, and two head-up display configurations, were developed and evaluated. Two longitudinal control response types consisting of a rate-command/attitude-hold system and a load factor-rate/load-factor-hold system were also compared. The complete set of piloting aids, which consisted of the autothrottle, throttle director, and flight director, improved the average Cooper-Harper flying qualities ratings from 8 to 2.6, even though identical inner-loop stability and control augmentation was provided in all cases. The flight director was determined to be the most critical of these aids, and the cruise turn maneuver was unachievable to adequate performance specifications in the absence of this flight director.

  13. Rotational maneuver of ferromagnetic nanowires for cell manipulation.

    PubMed

    Zhao, Yi; Zeng, Hansong

    2009-09-01

    1-D magnetic nanowires provide a powerful tool for investigating biological systems because such nanomaterials possess unique magnetic properties, which allow effective manipulation of cellular and subcellular objects. In this study, we report the rotational maneuver of ferromagnetic nanowires and their applications in cell manipulation. The rotational maneuver is studied under two different suspension conditions. The rotation of nanowires in the fluid is analyzed using Stokes flow assumption. Experimental results show that when the nanowires develop contacts with the bottom surfaces, the rotational maneuver under a modest external magnetic field can generate rapid lateral motion. The floating nanowires, on the other hand, do not exhibit substantial lateral displacements. Cell manipulation using skeletal myoblasts C2C12 shows that living cells can be manipulated efficiently on the bottom surface by the rotational maneuver of the attached nanowires. We also demonstrate the use of rotational maneuver of nanowires for creating 3-D nanowire clusters and multicellular clusters. This study is expected to add to the knowledge of nanowire-based cell manipulation and contribute to a full spectrum of control strategies for efficient use of nanowires for micro-total-analysis. It may also facilitate mechanobiological studies at cellular level, and provide useful insights for development of 3-D in vivo-like multicellular models for various applications in tissue engineering.

  14. Pursuit-evasion games with information uncertainties for elusive orbital maneuver and space object tracking

    NASA Astrophysics Data System (ADS)

    Shen, Dan; Jia, Bin; Chen, Genshe; Blasch, Erik; Pham, Khanh

    2015-05-01

    This paper develops and evaluates a pursuit-evasion (PE) game approach for elusive orbital maneuver and space object tracking. Unlike the PE games in the literature, where the assumption is that either both players have perfect knowledge of the opponents' positions or use primitive sensing models, the proposed PE approach solves the realistic space situation awareness (SSA) problem with imperfect information, where the evaders will exploit the pursuers' sensing and tracking models to confuse their opponents by maneuvering their orbits to increase the uncertainties, which the pursuers perform orbital maneuvers to minimize. In the game setup, each game player P (pursuer) and E (evader) has its own motion equations with a small continuous low-thrust. The magnitude of the low thrust is fixed and the direction can be controlled by the associated game player. The entropic uncertainty is used to generate the cost functions of game players. The Nash or mixed Nash equilibrium is composed of the directional controls of low-thrusts. Numerical simulations are emulated to demonstrate the performance. Simplified perturbations models (SGP4/SDP4) are exploited to calculate the ground truth of the satellite states (position and speed).

  15. Reducing Pointing Errors During Cassini Reaction Control System Orbit Trim Maneuvers

    NASA Technical Reports Server (NTRS)

    Rizvi, Farheen

    2013-01-01

    The effect of altering a gain parameter in the Cassini reaction control system (RCS) delta-V controller on the maneuver execution errors during orbit trim maneuvers (OTMs) is explored. Cassini consists of two reaction control thruster branches (A & B) each with eight thrusters. Currently, the B-branch is operational while the A-branch serves as a back-up. The four Z-thrusters control the X and Y-axes, while the four Y-thrusters control the Z-axis. During an OTM, the Z-thrusters fire to maintain the X and Y-axes pointing within an attitude control dead-zone (-10 to 10 milliradians). The errors do not remain at zero due to pointing error sources such as spacecraft center of mass offset from the geometric center of the Z-facing thrusters, and variability in the thruster forces due to the thruster hardware differences. The delta-V reaction control system (RCS) controller ensures that the attitude error remains within this dead-zone. Gain parameters within the RCS delta-V controller affect the maneuver execution errors. Different parameter values are used to explore effect on these errors. It is found that pointing error decreases and magnitude error increases rapidly for gain parameters 10 times greater than the current parameter values used in the flight software.

  16. Real-time pilot guidance system for improved flight-test maneuvers

    NASA Technical Reports Server (NTRS)

    Meyer, R. R., Jr.; Schneider, E. T.

    1983-01-01

    The Dryden Flight Research Facility has developed a pilot trajectory guidance system that is intended to increase the accuracy of flight-test data and decrease the time required to achieve and maintain desired test conditions, or both. The system usually presented to the pilot computed differences between reference or desired and actual flight state conditions. The pilot then used a cockpit display as an aid to acquire and hold desired test conditions. This paper discusses various flight-test maneuvers and the quality of data obtained using the guidance system. Some comparisons are made between the quality of maneuvers obtained with and without the system. Limited details of the guidance system and algorithms used are included. In general, the guidance system improved the quality of the maneuvers and trajectories flown, as well as allowing trajectories to be flown that would not have been possible without the system. This system has moved from the developmental stage to full operational use in various Dryden research and test aircraft.

  17. Real-time pilot guidance system for improved flight test maneuvers

    NASA Technical Reports Server (NTRS)

    Meyer, R. R., Jr.; Schneider, E. T.

    1984-01-01

    The Dryden Flight Research Facility of the NASA Ames Research Center has developed a pilot trajectory guidance system that increases the accuracy of flight-test data and decreases the time required to achieve and maintain desired test conditions. The system usually presented to the pilot computed differences between reference or desired and actual flight state conditions. The pilot then used a cockpit display as an aid to acquire and hold desired test conditions. This paper discusses various flight-test maneuvers and the quality of data obtained using the guidance system. Some comparisons are made between the quality of maneuvers obtained with and without the system. Limited details of the guidance system and algorithms used are included. In general, the guidance system improved the quality of the maneuvers and trajectories flown, as well as allowing trajectories to be flown that would not have been possible without the system. This system has moved from the developmental stage to full operational use in various Dryden research and test aircraft.

  18. Comparison of Knee Moments and Landing Patterns During a Lateral Cutting Maneuver: Shod Vs. Barefoot.

    PubMed

    Bisesti, Brianna A; Lawrence, Michael A; Koch, Alexander J; Carlson, Lara A

    2015-11-01

    Noncontact anterior cruciate ligament (ACL) injuries often occur during lateral cutting maneuvers, in which extension, adduction, and external rotation create high loads on the ACL. The aim of this study was to examine knee moments and foot strike patterns during lateral cutting when shod (SD) and barefoot (BF). Fifteen NCAA Division III athletes (7 female and 8 male; age 20.2 ± 1.5 years; mass 71.5 ± 11.3 kg; height, 1.7 ± 0.06 m) without lower limb pathologies were analyzed during 5 trials of 45° lateral cutting maneuvers for each limb in both BF and SD conditions with the approach speed of 4.3 m·s. Kinetic and kinematic data were collected using an 8-camera motion capture system and a force plate with collection rates at 240 Hz and 2400 Hz, respectively. Paired t-tests were used to determine differences conditions. The SD condition produced a significantly (p ≤ 0.05) greater peak adduction moment and cutting, whereas BF caused more anterior foot strike. Lateral cutting when BF places no more stress on the ACL than when SD. Our findings suggest that lateral cutting maneuvers when BF will not increase stress on the ACL. PMID:26506061

  19. The essential oils from Zanthoxylum schinifolium pericarp induce apoptosis of HepG2 human hepatoma cells through increased production of reactive oxygen species.

    PubMed

    Paik, Soon-Young; Koh, Kyung-Hee; Beak, Sung-Mok; Paek, Seung-Hwan; Kim, Jung-Ae

    2005-05-01

    The volatile extract from dried pericarp of Zanthoxylum schinifolium that was obtained by simultaneous distillation with dichloromethane and water was composed of 29.9% geranyl acetate, 15.8% citronella, 15.4% sabinene and the minor volatile components included beta-myrcene, linalool, (-)-isopulegol, citronellyl acetate, 1,4-dimethyl pyrazole, alpha-terpinene, 3-methyl-6-(1-methylethyl)-2-cyclo-hexene-1-o1 and trans-geraniol. The volatile extract decreased the cell viability and induced apoptotic death in HepG2 human hepatoma cells in a concentration- and time-related manner. In addition, the volatile extract increased the production of reactive oxygen species in a dose-dependent manner. Pretreatment of the cells with Trolox, a well-known antioxidant, significantly suppressed the generation of reactive oxygen species and cell death induced by the extract. However, caspase-3 activity was not changed in the extract-treated cells, suggesting that the extract-induced apoptosis of HepG2 cells is caspase-3 independent. Furthermore, in nude mice inoculated with Huh-7 human hepatoma cells, the extract significantly inhibited tumor development. These results suggest that the volatile extract from Zanthoxylum schinifolium pericarpium is a good candidate for hepatocellular carcinoma (HCC) therapy and that reactive oxygen species are the key signaling molecules in the volatile extract-induced cell death in HepG2 cells. PMID:15863882

  20. Effects of epinephrine and lactate on the increase in oxygen consumption of non-exercising skeletal muscle after aerobic exercise

    NASA Astrophysics Data System (ADS)

    Murakami, Motohide; Katsumura, Toshihito; Hamaoka, Takatumi; Osada, Takuya; Sako, Takayuki; Higuchi, Hiroyuki; Esaki, Kazuki; Kime, Ryotaro; Shimomitsu, Teruichi

    2000-10-01

    The purpose of this study was to measure O2 consumption of nonexercising skeletal muscles (VO2nonex) at rest and after aerobic exercise and to investigate the stimulant factors of O2 consumption. In experiment 1, we measured the resting metabolic rate of the finger flexor muscles in seven healthy males by 31P-magnetic resonance spectroscopy during a 15 min arterial occlusion. In experiment 2, the VO2nonex of the finger flexor muscles was measured using near infrared continuous wave spectroscopy at rest, immediate postexercise, and 3, 5, 10, 15, and 20 min following a cycling exercise at a workload corresponding to 50% of peak pulmonary O2 uptake for 20 min. We also monitored deep tissue temperature in the VO2nonex measurement area and determined catecholamines and lactate concentrations in the blood at rest and immediate postexercise. VO2nonex at rest was 1.1 +/- 0.1 (mu) M O2/s (mean +/- standard error) and VO2nonex after exercise increased 59.6 +/- 7.2% (p < 0.001) from the resting values. There were significant correlations between the increase in VO2nonex and the increase in epinephrine concentration (p < 0.01), and between the increase in VO2nonex and the increase in lactate concentration (p < 0.05). These results suggest that epinephrine and lactate concentrations are important VO2nonex stimulant factors.

  1. The cerebrovascular response to graded Valsalva maneuvers while standing

    PubMed Central

    Perry, Blake G.; Mündel, Toby; Cochrane, Darryl J.; Cotter, James D.; Lucas, Samuel J. E.

    2014-01-01

    Abstract The Valsalva maneuver (VM) produces large and abrupt increases in mean arterial pressure (MAP) at the onset of strain (Phase I), however, hypotension, sufficient to induce syncope, occurs upon VM release (phase III). We examined the effect of VM intensity and duration on middle cerebral artery blood velocity (MCAv) responses. Healthy men (n =10; mean ± SD: 26 ± 4 years) completed 30%, 60%, and 90% of their maximal VM mouth pressure, for 5 and 10 sec (order randomized) while standing. Beat‐to‐beat MCAv and MAP during phase I (peak), at nadir (phase III), and recovery are reported as the change from standing baseline. During phase I, MCAv rose 15 ± 6 cm·s−1 (P <0.001), which was not reliably different between intensities (P =0.11), despite graded increases in MAP (P <0.001; e.g., +12 ± 9 mmHg vs. +35 ± 14 for 5 sec 30% and 90% VM, respectively). During Phase III, the MCAv response was duration‐ (P = 0.045) and intensity dependent (P < 0.001), with the largest decrease observed following the 90% VM (e.g., −19 ± 13 and −15 ± 11 cm·s−1 for 5 and 10 sec VM, respectively) with a concomitant decrease in MAP (P <0.001, −23 ± 11 and −23 ± 9 mmHg). This asymmetric response may be attributable to the differential modulators of MCAv throughout the VM. The mechanical effects of the elevated intrathoracic pressure during phase I may restrain increases in cerebral perfusion via related increases in intracranial pressure; however, during phase III the decrease in MCAv arises from an abrupt hypotension, the extent of which is dependent upon both the duration and intensity of the VM. PMID:24744902

  2. Plasma reactive oxygen metabolites and non-enzymatic antioxidant capacity are not affected by an acute increase of metabolic rate in zebra finches.

    PubMed

    Beamonte-Barrientos, Rene; Verhulst, Simon

    2013-07-01

    Understanding the sources of variation in oxidative stress level is a challenging issue due to the implications of oxidative stress for late age diseases, longevity and life-history trade-offs. Reactive oxygen species that cause oxidative stress are mostly a by-product of energy metabolism and it is therefore often assumed that oxidative stress is proportional to energy consumption. In mammals, an increased metabolic rate induced by cold exposure generally increases oxidative stress. However, compared to mammals, birds generate fewer free radicals per ATP produced and hence it is not obvious that, in birds, a cold-induced increase of metabolic rate increase oxidative stress. We tested whether cold-induced increase in metabolic rate increased oxidative stress in zebra finches by exposing individuals to cold and warm overnight temperatures. We registered metabolic rate and plasma levels of non-enzymatic antioxidants and reactive oxygen metabolites (ROMs), a measure of oxidative damage. Metabolic rate was on average 88 % higher in cold compared to warm temperature, with females being stronger affected than males. However, temperature had no effect on plasma antioxidants or our measure of oxidative damage. Middle-age birds had higher levels of plasma antioxidants than younger and older birds, but age was unrelated to ROMs. Birds showed repeatability of plasma ROMs across temperatures but not of non-enzymatic antioxidants. In contrast to similar studies in mammals, our results do not show evidence of increased oxidative stress in plasma after an acute cold-induced increase of metabolic rate but research in more bird species is needed to assess the generality of this pattern.

  3. Maneuver Planning for Conjunction Risk Mitigation with Ground-track Control Requirements

    NASA Technical Reports Server (NTRS)

    McKinley, David

    2008-01-01

    The planning of conjunction Risk Mitigation Maneuvers (RMM) in the presence of ground-track control requirements is analyzed. Past RMM planning efforts on the Aqua, Aura, and Terra spacecraft have demonstrated that only small maneuvers are available when ground-track control requirements are maintained. Assuming small maneuvers, analytical expressions for the effect of a given maneuver on conjunction geometry are derived. The analytical expressions are used to generate a large trade space for initial RMM design. This trade space represents a significant improvement in initial maneuver planning over existing methods that employ high fidelity maneuver models and propagation.

  4. On spacecraft maneuvers control subject to propellant engine modes.

    PubMed

    Mazinan, A H

    2015-09-01

    The paper attempts to address a new control approach to spacecraft maneuvers based upon the modes of propellant engine. A realization of control strategy is now presented in engine on mode (high thrusts as well as further low thrusts), which is related to small angle maneuvers and engine off mode (specified low thrusts), which is also related to large angle maneuvers. There is currently a coarse-fine tuning in engine on mode. It is shown that the process of handling the angular velocities are finalized via rate feedback system in engine modes, where the angular rotations are controlled through quaternion based control (QBCL)strategy in engine off mode and these ones are also controlled through an optimum PID (OPIDH) strategy in engine on mode.

  5. A Maneuvering Flight Noise Model for Helicopter Mission Planning

    NASA Technical Reports Server (NTRS)

    Greenwood, Eric; Rau, Robert; May, Benjamin; Hobbs, Christopher

    2015-01-01

    A new model for estimating the noise radiation during maneuvering flight is developed in this paper. The model applies the Quasi-Static Acoustic Mapping (Q-SAM) method to a database of acoustic spheres generated using the Fundamental Rotorcraft Acoustics Modeling from Experiments (FRAME) technique. A method is developed to generate a realistic flight trajectory from a limited set of waypoints and is used to calculate the quasi-static operating condition and corresponding acoustic sphere for the vehicle throughout the maneuver. By using a previously computed database of acoustic spheres, the acoustic impact of proposed helicopter operations can be rapidly predicted for use in mission-planning. The resulting FRAME-QS model is applied to near-horizon noise measurements collected for the Bell 430 helicopter undergoing transient pitch up and roll maneuvers, with good agreement between the measured data and the FRAME-QS model.

  6. Attitude-Control Algorithm for Minimizing Maneuver Execution Errors

    NASA Technical Reports Server (NTRS)

    Acikmese, Behcet

    2008-01-01

    A G-RAC attitude-control algorithm is used to minimize maneuver execution error in a spacecraft with a flexible appendage when said spacecraft must induce translational momentum by firing (in open loop) large thrusters along a desired direction for a given period of time. The controller is dynamic with two integrators and requires measurement of only the angular position and velocity of the spacecraft. The global stability of the closed-loop system is guaranteed without having access to the states describing the dynamics of the appendage and with severe saturation in the available torque. Spacecraft apply open-loop thruster firings to induce a desired translational momentum with an extended appendage. This control algorithm will assist this maneuver by stabilizing the attitude dynamics around a desired orientation, and consequently minimize the maneuver execution errors.

  7. On spacecraft maneuvers control subject to propellant engine modes.

    PubMed

    Mazinan, A H

    2015-09-01

    The paper attempts to address a new control approach to spacecraft maneuvers based upon the modes of propellant engine. A realization of control strategy is now presented in engine on mode (high thrusts as well as further low thrusts), which is related to small angle maneuvers and engine off mode (specified low thrusts), which is also related to large angle maneuvers. There is currently a coarse-fine tuning in engine on mode. It is shown that the process of handling the angular velocities are finalized via rate feedback system in engine modes, where the angular rotations are controlled through quaternion based control (QBCL)strategy in engine off mode and these ones are also controlled through an optimum PID (OPIDH) strategy in engine on mode. PMID:26117285

  8. Severe turbulence and maneuvering from airline flight records

    NASA Technical Reports Server (NTRS)

    Wingrove, R. C.; Basch, R. E., Jr.

    1992-01-01

    Digital flight records from reported clear-air turbulence incidents are used to determine winds, to determine maneuver G loads, and to analyze control problems. Severe turbulence is found downwind of mountains and thunderstorms associated with vortices in atmospheric waves. It is also found in strong updrafts above thunderstorm buildups that are not detected by onboard weather radar. An important finding is that there are large maneuvering loads in over half of the reported clear-air turbulence incidents. Maneuvering loads are determined through an analysis of the short-term variations in elevator deflection and aircraft pitch angle. For altitude control in mountain waves the results indicate that small pitch angle changes with proper timing are sufficient to counter the vertical winds. For airspeed control in strong mountain waves, however, there is neither the available thrust nor the quickness in engine response necessary to counter the large and rapid variations in horizontal wind.

  9. Operational Challenges In TDRS Post-Maneuver Orbit Determination

    NASA Technical Reports Server (NTRS)

    Laing, Jason; Myers, Jessica; Ward, Douglas; Lamb, Rivers

    2015-01-01

    The GSFC Flight Dynamics Facility (FDF) is responsible for daily and post maneuver orbit determination for the Tracking and Data Relay Satellite System (TDRSS). The most stringent requirement for this orbit determination is 75 meters total position accuracy (3-sigma) predicted over one day for Terra's onboard navigation system. To maintain an accurate solution onboard Terra, a solution is generated and provided by the FDF Four hours after a TDRS maneuver. A number of factors present challenges to this support, such as maneuver prediction uncertainty and potentially unreliable tracking from User satellities. Reliable support is provided by comparing an extended Kalman Filter (estimated using ODTK) against a Batch Least Squares system (estimated using GTDS).

  10. Orbital maneuver optimization using time-explicit power series

    NASA Astrophysics Data System (ADS)

    Thorne, James D.

    2011-05-01

    Orbital maneuver transfer time optimization is traditionally accomplished using direct numerical sampling to find the mission design with the lowest delta-v requirements. The availability of explicit time series solutions to the Lambert orbit determination problem allows for the total delta-v of a series of orbital maneuvers to be expressed as an algebraic function of only the individual transfer times. The delta-v function is then minimized for a series of maneuvers by finding the optimal transfer times for each orbital arc. Results are shown for the classical example of the Hohmann transfer, a noncoplanar transfer as well as an interplanetary fly-by mission to the asteroids Pallas and Juno.

  11. A prescription for the Epley maneuver: www.youtube.com?

    PubMed Central

    Burke, James F.; Skolarus, Lesli E.; Callaghan, Brian C.; Fife, Terry D.; Baloh, Robert W.; Fendrick, A. Mark

    2012-01-01

    Objectives: Video-sharing Web sites are being used for information about common conditions including dizziness. The Epley maneuver (EM) is a simple and effective treatment for benign paroxysmal positional vertigo (BPPV) of the posterior canal. However, the maneuver is underused in routine care. In this study, we aimed to describe and analyze the available information about the EM on youtube.com. Methods: A YouTube search was performed on August 31, 2011, for videos that demonstrated the entire EM. Detailed data were abstracted from each video and corresponding Web site. Videos were rated on the accuracy of the maneuver by 2 authors, with differences resolved by adjudication. Comments posted by viewers were assessed for themes regarding video use. Results: Of the 3,319 videos identified, 33 demonstrated the EM. The total number of hits for all videos was 2,755,607. The video with the most hits (802,471) was produced by the American Academy of Neurology. Five of the videos accounted for 85% of all the hits. The maneuver demonstration was rated as accurate in 64% (21) of the videos. Themes derived from the 424 posted comments included patients self-treating with the maneuver after reviewing the videos, and providers using the videos as a prescribed treatment or for educational purposes. Conclusion: Accurate video demonstration of the Epley maneuver is available and widely viewed on YouTube. Video-sharing media may be an important way to disseminate effective interventions such as the EM. The impact of video Web sites on outcomes and costs of care is not known and warrants future study. PMID:22826542

  12. Influence of increased dissolved oxygen concentration on the formation of secondary metabolites by manumycin-producing Streptomyces parvulus.

    PubMed

    Kaiser, D; Onken, U; Sattler, I; Zeeck, A

    1994-05-01

    The influence of increased dissolved O2 concentrations (DOC) on cell growth and production of the secondary metabolite manumycin by a strain of Streptomyces parvulus (Tü 64) was investigated in a stirred tank fermentor. DOC is given as the O2 partial pressure (po2) in the gas phase in an equilibrium state with the liquid phase. Growth of S. parvulus was not influenced up to DOC equivalent to po2 = 1260 mbar. At po2 = 2205 mbar the maximum biomass concentration was lowered by 40%. Production of manumycin was markedly influenced by DOC and reached the maximal concentration at po2 = 315 mbar. At increased DOC three new metabolites were observed. Two of them, 64p-A and 64p-B, were identified as carboxamides, which represent the branched side chain of the manumycin molecule and a derivative with a shorter chain length. The third metabolite, 64p-C, was a manumycin derivative containing an aromatic ring system. Feeding of glycerol during the production phase increased the total yield and showed a similar effect of DOC. Since DOC has significant regulation effects on product formation and selectivity, it should be used as a major parameter in development strategies of aerobic microbial processes.

  13. Maneuver Acoustic Flight Test of the Bell 430 Helicopter

    NASA Technical Reports Server (NTRS)

    Watts, Michael E.; Snider, Royce; Greenwood, Eric; Baden, Joel

    2012-01-01

    A cooperative flight test by NASA, Bell Helicopter and the U.S. Army to characterize the steady state acoustics and measure the maneuver noise of a Bell Helicopter 430 aircraft was accomplished. The test occurred during June/July, 2011 at Eglin Air Force Base, Florida. This test gathered a total of 410 data points over 10 test days and compiled an extensive data base of dynamic maneuver measurements. Three microphone configurations with up to 31 microphones in each configuration were used to acquire acoustic data. Aircraft data included DGPS, aircraft state and rotor state information. This paper provides an overview of the test.

  14. Astronaut Alan Bean flies the Astronaut Maneuvering Equipment

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Alan L. Bean, Skylab 3 commander, flies the M509 Astronaut Maneuvering Equipment in the foreward dome area of the Orbital Workshop (OWS) on the space station cluster in Earth orbit. Bean is strapped in to the back-mounted, hand-controlled Automatically Stabilized Maneuvering Unit (ASMU). He is wearing a pressure suit for this run of the M509 experiment, but other ASMU tests are done in shirt sleeves. The dome area where the experiment is conducted is about 22 feet in diameter and 19 feet from top to bottom.

  15. Effects of abdominal stabilization maneuvers on the control of spine motion and stability against sudden trunk perturbations.

    PubMed

    Vera-Garcia, Francisco J; Elvira, José L L; Brown, Stephen H M; McGill, Stuart M

    2007-10-01

    Much discussion exists about which is the most effective technique to improve spine stability. The purpose of this study was to evaluate the effectiveness of abdominal bracing and abdominal hollowing maneuvers to control spine motion and stability against rapid perturbations. Eleven healthy males were posteriorly loaded in different experimental conditions: resting with no knowledge of the perturbation timing; performing each of the stabilization maneuvers at 10%, 15% and 20% of internal oblique maximum voluntary contraction with no knowledge of the perturbation timing; and naturally coactivating the trunk muscles when perturbation timing was known. An EMG biofeedback system was used to control the pattern and intensity of abdominal coactivation. The muscular preactivation of seven trunk muscles (bilaterally registered), the applied force, and the torso muscular and kinematic responses to loading were measured; and the spine stability and compression were modeled. The hollowing maneuver was not effective for reducing the kinematic response to sudden perturbation. On the contrary, the bracing maneuver fostered torso cocontraction, reduced lumbar displacement, and increased trunk stability, but at the cost of increasing spinal compression. When the timing of the perturbation was known, the participants were able to stabilize the trunk while imposing smaller spine compressive loads. PMID:16996278

  16. Snake venom causes apoptosis by increasing the reactive oxygen species in colorectal and breast cancer cell lines

    PubMed Central

    Al-Asmari, Abdulrahman Khazim; Riyasdeen, Anvarbatcha; Al-Shahrani, Mohammad Hamed; Islam, Mozaffarul

    2016-01-01

    Snake venom possesses various kinds of proteins and neurotoxic polypeptides, which can negatively interfere with the neurotransmitter signaling cascade. This phenomenon occurs mainly due to the blocking of ion channels in the body system. Envenomation prevents or severely interrupts nerve impulses from being transmitted, inhibition of adenosine triphosphate synthesis, and proper functioning of the cardiac muscles. However, some beneficial properties of venoms have also been reported. The aim of this study was to examine the snake venom as an anticancer agent due to its inhibitory effects on cancer progression such as cell motility, cell invasion, and colony formation. In this study, the effect of venoms on phenotypic changes and the change on molecular level in colorectal and breast cancer cell lines were examined. A reduction of 60%–90% in cell motility, colony formation, and cell invasion was observed when these cell lines were treated with different concentrations of snake venom. In addition, the increase in oxidative stress that results in an increase in the number of apoptotic cancer cells was significantly higher in the venom-treated cell lines. Further analysis showed that there was a decrease in the expression of pro-inflammatory cytokines and signaling proteins, strongly suggesting a promising role for snake venom against breast and colorectal cancer cell progression. In conclusion, the snake venoms used in this study showed significant anticancer properties against colorectal and breast cancer cell lines. PMID:27799796

  17. Khz (fusion product of Ganoderma lucidum and Polyporus umbellatus mycelia) induces apoptosis in human colon carcinoma HCT116 cells, accompanied by an increase in reactive oxygen species, activation of caspase 3, and increased intracellular Ca²⁺.

    PubMed

    Kim, Tae Hwan; Kim, Ju Sung; Kim, Zoo Haye; Huang, Ren Bin; Chae, Young Lye; Wang, Ren Sheng

    2015-03-01

    Khz (a fusion mycelium of Ganoderma lucidum and Polyporus umbellatus mycelia) is isolated from ganoderic acid and P. umbellatus and it exerts antiproliferative effects against malignant cells. However, no previous study has reported the inhibitory effects of Khz on the growth of human colon cancer cells. In the present study, we found that Khz suppressed cell division and induced apoptosis in HCT116 cells. Khz cytotoxicity was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Khz reduced cell viability and mitochondrial membrane potential levels and it also induced disruption of the mitochondrial membrane potential and increased calcium concentration and reactive oxygen species generation. Khz increased caspase 3, PARP, caspase 7, and caspase 9 levels, but reduced Bcl-2 protein levels. Flow cytometry showed that the percentage of HCT116 cells in the sub-G1 phase of the cell cycle increased in response to Khz treatment.

  18. Mitochondrial dysfunction promotes breast cancer cell migration and invasion through HIF1α accumulation via increased production of reactive oxygen species.

    PubMed

    Ma, Jia; Zhang, Qing; Chen, Sulian; Fang, Binbin; Yang, Qingling; Chen, Changjie; Miele, Lucio; Sarkar, Fazlul H; Xia, Jun; Wang, Zhiwei

    2013-01-01

    Although mitochondrial dysfunction has been observed in various types of human cancer cells, the molecular mechanism underlying mitochondrial dysfunction mediated tumorigenesis remains largely elusive. To further explore the function of mitochondria and their involvement in the pathogenic mechanisms of cancer development, mitochondrial dysfunction clones of breast cancer cells were generated by rotenone treatment, a specific inhibitor of mitochondrial electron transport complex I. These clones were verified by mitochondrial respiratory defect measurement. Moreover, those clones exhibited increased reactive oxygen species (ROS), and showed higher migration and invasive behaviors compared with their parental cells. Furthermore, antioxidant N-acetyl cysteine, PEG-catalase, and mito-TEMPO effectively inhibited cell migration and invasion in these clones. Notably, ROS regulated malignant cellular behavior was in part mediated through upregulation of hypoxia-inducible factor-1 α and vascular endothelial growth factor. Our results suggest that mitochondrial dysfunction promotes cancer cell motility partly through HIF1α accumulation mediated via increased production of reactive oxygen species. PMID:23922721

  19. Study of a very low cost air combat maneuvering trainer aircraft

    NASA Technical Reports Server (NTRS)

    Hill, G. C.; Bowles, J. V.

    1976-01-01

    A very low cost aircraft for performing Air Combat Maneuvering (ACM) training was studied using the BD-5J sport plane as a point of departure. The installation of a larger engine and increased fuel capacity were required to meet the performance and mission objectives. Reduced wing area increased the simulation of the ACM engagement, and a comparison with current tactical aircraft is presented. Other factors affecting the training transfer are considered analytically, but a flight evaluation is recommended to determine the concept utility.

  20. Catha edulis Extract Induces H9c2 Cell Apoptosis by Increasing Reactive Oxygen Species Generation and Activation of Mitochondrial Proteins

    PubMed Central

    Mohan, Syam; Abdelwahab, Siddig Ibrahim; Hobani, Yahya Hasan; Syam, Suvitha; Al-Zubairi, Adel S.; Al-Sanousi, Rashad; Oraiby, Magbool Essa

    2016-01-01

    Background: Catha edulis (Khat) is an evergreen shrub or small tree, traditionally used by various peoples of the Arabian Peninsula and Africa as an integral component of the socioeconomic traditions. It is believed that the psychostimulant nature and toxic nature of khat is primarily due to the presence of cathinone and cathine respectively. Studies have shown that khat chewing is closely associated with cardiac complications, especially myocardial infarction. Hence in this study, we exposed cathine-rich khat extract in a cardiomyoblast H9c2 (2-1) cell line to check the cell death mechanism. Materials and Methods: Extraction of Catha edulis leaves was done and the presence of cathine was confirmed with LC-MS-MS. The anti-proliferative activity was assayed using MTT and apoptosis detection by acridine orange/propidium iodide assay. The expression of Bcl-2 and Bax protein and caspase-3/7 expression were analyzed. The level of reactive oxygen species generation was also evaluated. Results: The khat extract showed an IC50 value of 86.5 μg/ml at 48 hours treatment. We have observed significant early apoptosis events by intervened acridine orange within the fragmented DNA with bright green fluorescence upon treatment. The Bcl-2 expression in the treatment with IC50 concentration of khat extract for 24, 48 and 72 hours of incubation significantly decreased with increase in bax level. The increased activation of caspase-3/7 was significantly observed upon treatment together with significant increase of ROS was detected at 24 and 48 hours treatment. Conclusion: Collectively, our results provide insight into the mechanisms by which Catha edulis leaves mediate cell death in cardiomyocytes. SUMMARY Catha edulis (Khat) is an evergreen psychotropic shrub or small treeExtraction of khat leaves was done and the presence of cathine was confirmed with liquid chromatography-mass spectrometry-mass spectrometryThe khat extract showed an IC50 value of 86.5 μg/ml at 48 h treatment in

  1. High-yield production of biologically active recombinant protein in shake flask culture by combination of enzyme-based glucose delivery and increased oxygen transfer

    PubMed Central

    2011-01-01

    This report describes the combined use of an enzyme-based glucose release system (EnBase®) and high-aeration shake flask (Ultra Yield Flask™). The benefit of this combination is demonstrated by over 100-fold improvement in the active yield of recombinant alcohol dehydrogenase expressed in E. coli. Compared to Terrific Broth and ZYM-5052 autoinduction medium, the EnBase system improved yield mainly through increased productivity per cell. Four-fold increase in oxygen transfer by the Ultra Yield Flask contributed to higher cell density with EnBase but not with the other tested media, and consequently the product yield per ml of EnBase culture was further improved. PMID:22152005

  2. Automated Rotational Percussion Bed and Bronchoscopy Improves Respiratory Mechanics and Oxygenation in ARDS Patients Supported with Extracorporeal Membrane Oxygenation.

    PubMed

    Sharma, Nirmal S; Wille, Keith M; Bellot, S Christopher; Diaz-Guzman, Enrique

    2016-01-01

    Extracorporeal membrane oxygenation (ECMO) has been used to provide "lung rest" through the use of low tidal volume (6 ml/kg) and ultralow tidal volume (<6 ml/kg) ventilation in acute respiratory distress syndrome (ARDS). Low and ultralow tidal volume ventilation can result in low dynamic respiratory compliance and potentially increased retention of airway secretions. We present our experience using automated rotational percussion beds (ARPBs) and bronchoscopy in four ARDS patients to manage increased pulmonary secretions. These beds performed automated side-to-side tilt maneuver and intermittent chest wall percussion. Their use resulted in substantial reduction in peak and plateau pressures in two patients on volume control ventilation, while the driving pressures (inspiratory pressure) to attain the desired tidal volumes in patients on pressure control ventilation also decreased. In addition, mean partial pressure of oxygen in arterial blood (PaO2)/fraction of inspired oxygen (FiO2) ratio (109 pre-ARPB vs. 157 post-ARPB), positive end-expiratory pressure (10 cm H2O vs. 8 cm H2O), and FiO2 (0.88 vs. 0.52) improved after initiation of ARPB. The improvements in the respiratory mechanics and oxygenation helped us to initiate early ECMO weaning. Based on our experience, the use of chest physiotherapy, frequent body repositioning, and bronchoscopy may be helpful in the management of pulmonary secretions in patients supported with ECMO. PMID:26771392

  3. The impact of increased oxygen conditions on metal-contaminated sediments part II: effects on metal accumulation and toxicity in aquatic invertebrates.

    PubMed

    De Jonge, M; Teuchies, J; Meire, P; Blust, R; Bervoets, L

    2012-06-15

    The present study evaluated the effect of increasing oxygen concentrations in overlying surface water on the accumulation and toxicity of sediment-bound metals in the aquatic invertebrates Lumbriculus variegatus, Asellus aquaticus and Daphnia magna. A 54 days experiment using three experimental treatments (90% O(2) in overlying surface water, 40% O(2) and a non-polluted control) was conducted. At 6 different time points (after 0, 2, 5, 12, 32 and 54 days) acid volatile sulfides (AVS), simultaneously extracted metals (SEM) and total organic carbon (TOC) were measured in the superficial sediment layer (0-1 cm). At each time point, accumulated metal levels as well as the available energy stores were measured in L. variegatus and A. aquaticus and each time D. magna was exposed to surface water in a 24 h toxicity test. Additionally metallothionein-like protein (MTLP) induction was quantified in L. variegatus. Oxygen induced changes in sediment AVS resulted in faster accumulation of metals from contaminated sediments in A. aquaticus, while no differences in toxicity in this species were observed. Ag, Cr, As and Co accumulation as well as toxicity in water exposed D. magna were clearly enhanced after 54 days, caused by oxidation of metal-sulfide complexes. Due to their feeding and burrowing behaviour, metal accumulation and toxicity in L. variegatus was not influenced by geochemical characteristics. Nevertheless, a rapid induction of MTLP was observed in both the 90% O(2) and the 40% O(2) treatment. The present study showed that elevated oxygen concentrations in overlying surface water can directly enhance metal accumulation and toxicity in aquatic invertebrates, however this is highly dependent on the organisms ecology and most dominant metal exposure route (water vs. sediment).

  4. Hypothesis: increase of the ratio singlet oxygen plus superoxide radical to hydrogen peroxide changes stress defense response to programmed leaf death

    PubMed Central

    Sabater, Bartolomé; Martín, Mercedes

    2013-01-01

    The level of reactive oxygen species (ROS) increases under different stresses and, by destroying cellular components, may cause cell death. In addition, ROS are part of the complex network of transduction signals that induce defense reactions against stress or, alternatively, trigger programmed cell death, and key questions are the levels of each ROS that, respectively determine defense and death responses of the cell. The answer to those questions is difficult because there are several patterns of cell death that frequently appear mixed and are hardly distinguishable. Moreover, although considerable progresses have been achieved in the determination of the levels of specific ROS, critical questions remain on the ROS level in specific cell compartments. By considering chloroplasts as the main source of ROS in photosynthetic tissues at light, a comparison of the levels in stress and senescence of the chloroplastic activities involved in the generation and scavenging of ROS suggests plausible differences in the levels of specific ROS between stress defense and death. In effect, the three activities of the chlororespiratory chain increase similarly in stress defense response. However, in senescence, superoxide dismutase (SOD), that converts superoxide anion radical (O2∙−) to hydrogen peroxide (H2O2,) decreases, while the thylakoid Ndh complex, that favors the generation of singlet oxygen (1O2) and O2∙−, and peroxidase (PX), that consumes H2O2, increase. The obvious inference is that, in respect to defense response, the ratio (1O2 plus O2∙−)/H2O2 is increased in the senescence previous to cell death. We hypothesize that the different ROS ratios, probably through changes in the jasmonic acid/H2O2 ratio, could determine the activation of the defense network or the death network response of the cell. PMID:24324479

  5. Cardiac and Vascular Responses to Thigh Cuffs and Respiratory Maneuvers on Crewmembers of the International Space Station

    NASA Technical Reports Server (NTRS)

    Hamilton, Douglas; Sargsyan, Ashot E.; Garcia, Kathleen; Ebert, Douglas; Whitson, Peggy A.; Feiveson, Alan; Alferova, Irina V.; Dulchavsky, Scott A.; Matveev, Vladimir P.; Bogomolov, Valery V.; Duncan, J. Michael

    2011-01-01

    The transition to microgravity eliminates the hydrostatic gradients in the vascular system. The resulting fluid redistribution commonly manifests as facial edema, engorgement of the external neck veins, and a decrease in leg diameter. This experiment examined the responses to modified Valsalva and Mueller maneuvers measured by cardiac and vascular ultrasound (ECHO) in a baseline steady state and during preload reduction introduced with thigh occlusion cuffs used as a counter-measure device (Braslet cuffs) measured by cardiac and vascular ultrasound examinations. Methods: Nine International Space Station crewmember subjects (Expeditions 16 - 20) were examined in 15 experiment sessions 101 +/- 46.days after launch (mean +/- SD; 33 - 185). Twenty Seven cardiac and vascular parameters were obtained with/without respiratory maneuvers before and after tightening of the Braslet cuffs. Results: Non-physicians performed diagnostic-quality cardiac and vascular ultrasound examinations using remote guidance. Three of 27 combinations of maneuvers and Braslet or Braslet alone were identified as being significant changed when compared to baseline. Eleven of 81 differences between combinations of Mueller, Valsalva or baseline were significant and related to cardiac preload reduction or increase in lower extremity venous volume. Conclusions: Acute application of Braslet occlusion cuffs causes lower extremity fluid sequestration and exerts commensurate measurable effects on cardiac performance in microgravity. Ultrasound techniques to measure the hemodynamic effects of thigh cuffs in combination with respiratory maneuvers may serve as an invaluable tool in determining the volume status of the cardiac patient at the 'microgravity bedside'.

  6. Control of Spacecraft Control Laboratory Experiment (SCOLE) slew maneuvers

    NASA Technical Reports Server (NTRS)

    Kakad, Y. P.

    1987-01-01

    This is the second report of a set of two reports on the dynamics and control of slewing maneuvers of NASA Spacecraft Control Laboratory Experiment (SCOLE). The control problem of slewing maneuvers of SCOLE is developed in terms of an arbitrary maneuver about any given axis. The control system is developed for the combined problem of rigid-body slew maneuver and vibration suppression of flexible appendage. The control problem is formulated by incorporating the nonlinear equations derived in the previous report and is expressed in terms of a two-point boundary value problem utilizing a quadratic type of performance index. The two-point boundary value problem is solved as a hierarchical control problem with the overall system being split in terms of two subsystems, namely the slewing of the entire assembly and the vibration suppression of the flexible antenna. The coupling variables between the two dynamical subsystems are identified and these two subsystems for control purposes are treated independently in parallel at the first level. Then the state-space trajectory of the combined problem is optimized at the second level.

  7. Maneuvering and stability performance of a robotic tuna.

    PubMed

    Anderson, Jamie M; Chhabra, Narender K

    2002-02-01

    The Draper Laboratory Vorticity Control Unmanned Undersea Vehicle (VCUUV) is the first mission-scale, autonomous underwater vehicle that uses vorticity control propulsion and maneuvering. Built as a research platform with which to study the energetics and maneuvering performance of fish-swimming propulsion, the VCUUV is a self-contained free swimming research vehicle which follows the morphology and kinematics of a yellowfin tuna. The forward half of the vehicle is comprised of a rigid hull which houses batteries, electronics, ballast and hydraulic power unit. The aft section is a freely flooded articulated robot tail which is terminated with a lunate caudal fin. Utilizing experimentally optimized body and tail kinematics from the MIT RoboTuna, the VCUUV has demonstrated stable steady swimming speeds up to 1.2 m/sec and aggressive maneuvering trajectories with turning rates up to 75 degrees per second. This paper summarizes the vehicle maneuvering and stability performance observed in field trials and compares the results to predicted performance using theoretical and empirical techniques.

  8. 14 CFR 23.1567 - Flight maneuver placard.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... clear view of the pilot stating: “No acrobatic maneuvers, including spins, approved.” (b) For utility...); and (2) For those airplanes that do not meet the spin requirements for acrobatic category airplanes, an additional placard in clear view of the pilot stating: “Spins Prohibited.” (c) For...

  9. Enhanced Pseudo-Waypoint Guidance for Spacecraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Carson, John; Acikmese, behcet

    2008-01-01

    An enhanced version of the scheme reported in "Pseudo-Waypoint Guidance for Proximity Spacecraft Maneuvers" (NPO-42753), NASA Tech Briefs, Vol. 31, No. 6 (June 2007), page 73 was developed. To recapitulate: the scheme provides algorithms for guidance and control (G&C) of a spacecraft maneuvering near a small astronomical body. The open-loop guidance problem is solved in advance or in real time by use of the pseudo-waypoint generation (PWG) method. Feedback control is implemented to track PWG trajectories, in a manner that enables updating of G&C in a model-predictive manner. The scheme includes silent periods following each thruster firing. The original version of the scheme provides for a fire-first, followed-by-silence sequence, which is disadvantageous in that the silence after final firing precludes reduction of any remaining velocity error -- an unacceptable result in the case of a maneuver for which a specific final velocity is required. In the enhanced version, the scheme is augmented with a fire-second technique, so that the final velocity can be established with a much higher precision because both the guidance and feedback firing can be performed and ceased at the final maneuver time.

  10. Pseudo-Waypoint Guidance for Proximity Spacecraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Acikmese, Ahmet; Carson, John M., III

    2007-01-01

    A paper describes algorithms for guidance and control (G&C) of a spacecraft maneuvering near a planet, moon, asteroid, comet, or other small astronomical body. The algorithms were developed following a model-predictive-control approach along with a convexification of the governing dynamical equations, control constraints, and trajectory and state constraints.

  11. Skill Development for Maneuvering on the Information Highway.

    ERIC Educational Resources Information Center

    Mosley, Barbra; Edwards, Gloria

    To help students learn to navigate the information superhighway, a 2-hour pilot program with 10 hours of guided access time was developed to test a method for teaching the basics of maneuvering the superhighway and extracting information once located. This pilot was designed as a two-part instructional session. The first instructional session…

  12. Detail view of a starboard Orbiter Maneuvering and Reaction Control ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail view of a starboard Orbiter Maneuvering and Reaction Control Systems pod, removed from the orbiter and in it's carrier/transport vehicle at Kennedy Space Center. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  13. 14 CFR 27.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Limit maneuvering load factor. 27.337 Section 27.337 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... ranging from a positive limit of 3.5 to a negative limit of −1.0; or (b) Any positive limit...

  14. 14 CFR 29.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Limit maneuvering load factor. 29.337 Section 29.337 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... ranging from a positive limit of 3.5 to a negative limit of −1.0; or (b) Any positive limit...

  15. Transient Structured Distance as a Maneuver in Marital Therapy

    ERIC Educational Resources Information Center

    Greene, Bernard L.; And Others

    1973-01-01

    Experience with 73 cases has shown the value of Transient Structured Distance as a maneuver in marriage therapy. While the TSD is a radical form of intervention with risks of anxiety reactions, homosexual panic, or divorce, it has proved effective with difficult forms of acute or chronic marital disharmony. (Author)

  16. 33 CFR 157.450 - Maneuvering and vessel status information.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... information. 157.450 Section 157.450 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... CARRYING OIL IN BULK Interim Measures for Certain Tank Vessels Without Double Hulls Carrying Petroleum Oils § 157.450 Maneuvering and vessel status information. A tankship owner, master, or operator shall...

  17. Vibration suppression of fixed-time jib crane maneuvers

    SciTech Connect

    Parker, G.G.; Petterson, B.; Dohrmann, C.R.; Robinett, R.D.

    1995-02-01

    A jib crane consists of a pendulum-like end line attached to a rotatable jib. Within this general category of cranes there exist devices with multiple degrees of freedom including variable load-line length and variable jib length. These cranes are commonly used for construction and transportation applications. Point-to-point payload maneuvers using jib cranes are performed so as not to excite the spherical pendulum modes of their cable and payload assemblies. Typically, these pendulum modes, although time-varying, exhibit low frequencies. The resulting maneuvers are therefore performed slowly, contributing to high construction and transportation costs. The crane considered here consists of a spherical pendulum attached to a rigid jib. The other end of the jib is attached to a direct drive motor for generating rotational motion. A general approach is presented for determining the open-loop trajectories for the jib rotation for accomplishing fixed-time, point-to-point, residual oscillation free, symmetric maneuvers. These residual oscillation free trajectories purposely excite the pendulum modes in such a way that at the end of the maneuver the oscillatory degrees of freedom are quiescent. Simulation results are presented with experimental verification.

  18. LOCK, DOG HOUSE, CONTROL STATION, DAM GATE, MANEUVER BOAT No. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    LOCK, DOG HOUSE, CONTROL STATION, DAM GATE, MANEUVER BOAT No. 1, AND DAM. NOTE LOWER LOCK GATE IN FOREGROUND. LOOKING NORTH NORTHEAST. - Illinois Waterway, La Grange Lock and Dam, 3/4 mile south of Country 795N at Illinois River, Versailles, Brown County, IL

  19. EOS Terra Terra Constellation Exit/Future Maneuver Plans Update

    NASA Technical Reports Server (NTRS)

    Mantziaras, Dimitrios

    2016-01-01

    This EOS Terra Constellation Exit/Future Maneuver Plans Update presentation will discuss brief history of Terra EOM work; lifetime fuel estimates; baseline vs. proposed plan origin; resultant exit orbit; baseline vs. proposed exit plan; long term orbit altitude; revised lifetime proposal and fallback options.

  20. Hohmann-Hohmann and Hohmann-Phasing Cooperative Rendezvous Maneuvers

    NASA Astrophysics Data System (ADS)

    Dutta, Atri; Tsiotras, Panagiotis

    2009-01-01

    We consider the problem of cooperative rendezvous between two satellites in circular orbits, given a fixed time for the rendezvous to be completed, and assuming a circular rendezvous orbit. We investigate two types of cooperative maneuvers for which analytical solutions can be obtained. One is the case of two Hohmann transfers, henceforth referred to as HHCM, while the other, henceforth referred to as HPCM, is the case of a Hohmann transfer and a phasing maneuver. For the latter case we derive conditions on the phasing angle that make a HPCM rendezvous cheaper than a cooperative rendezvous on an orbit that is different than either the original orbits of the two participating satellites. It is shown that minimizing the fuel expenditure is equivalent to minimizing a weighted sum of the Δ Vs of the two orbital transfers, the weights being determined by the mass and engine characteristics of the satellites. Our results show that, if the time of rendezvous allows for a Hohmann transfer between the orbits of the satellites, the optimal rendezvous is either a noncooperative Hohmann transfer or a Hohmann-phasing cooperative maneuver. In both of these cases, the maneuver costs are determined analytically. A numerical example verifies these observations. Finally, we demonstrate the utility of this study for Peer-to-Peer (P2P) refueling of satellites residing in two different circular orbits.

  1. Increase in the efficiency of electric melting of pellets in an arc furnace with allowance for the energy effect of afterburning of carbon oxide in slag using fuel-oxygen burners

    NASA Astrophysics Data System (ADS)

    Stepanov, V. A.; Krakht, L. N.; Merker, E. E.; Sazonov, A. V.; Chermenev, E. A.

    2015-12-01

    The problems of increasing the efficiency of electric steelmaking using fuel-oxygen burners to supply oxygen for the afterburning of effluent gases in an arc furnace are considered. The application of a new energy-saving regime based on a proposed technology of electric melting is shown to intensify the processes of slag formation, heating, and metal decarburization.

  2. Effects of repeated Valsalva maneuver straining on cardiac and vasoconstrictive baroreflex responses

    NASA Technical Reports Server (NTRS)

    Convertino, Victor A.; Ratliff, Duane A.; Doerr, Donald F.; Ludwig, David A.; Muniz, Gary W.; Benedetti, Erik; Chavarria, Jose; Koreen, Susan; Nguyen, Claude; Wang, Jeff

    2003-01-01

    INTRODUCTION: We hypothesized that repeated respiratory straining maneuvers (repeated SM) designed to elevate arterial BPs (arterial baroreceptor loading) would acutely increase baroreflex responses. METHODS: We tested this hypothesis by measuring cardiac baroreflex responses to carotid baroreceptor stimulation (neck pressures), and changes in heart rate and diastolic BP after reductions in BP induced by a 15-s Valsalva maneuver in 10 female and 10 male subjects at 1, 3, 6, and 24 h after performing repeated SM. Baroreflex responses were also measured in each subject at 1, 3, 6, and 24 h at the same time on a separate day without repeated SM (control) in a randomized, counter-balanced cross-over experimental design. RESULTS: There was no statistical difference in carotid-cardiac and peripheral vascular baroreflex responses measured across time following repeated SM compared with the control condition. Integrated cardiac baroreflex response (deltaHR/ deltaSBP) measured during performance of a Valsalva maneuver was increased by approximately 50% to 1.1 +/- 0.2 bpm x mm Hg(-1) at 1 h and 1.0 +/- 0.1 bpm x mm Hg(-1) at 3 h following repeated SM compared with the control condition (0.7 +/- 0.1 bpm x mm Hg(-1) at both 1 and 3 h, respectively). However, integrated cardiac baroreflex response after repeated SM returned to control levels at 6 and 24 h after training. These responses did not differ between men and women. CONCLUSIONS: Our results are consistent with the notion that arterial baroreceptor loading induced by repeated SM increased aortic, but not carotid, cardiac baroreflex responses for as long as 3 h after repeated SM. We conclude that repeated SM increases cardiac baroreflex responsiveness which may provide patients, astronauts, and high-performance aircraft pilots with protection from development of orthostatic hypotension.

  3. Orbit determination across unknown maneuvers using the essential Thrust-Fourier-Coefficients

    NASA Astrophysics Data System (ADS)

    Ko, Hyun Chul; Scheeres, Daniel J.

    2016-01-01

    Any maneuver performed by a satellite transitioning between two arbitrary orbital states can be represented as an equivalent maneuver involving Thrust-Fourier-Coefficients (TFCs). With a selected TFC set as a basis, a thrust acceleration can be constructed to interpolate two unconnected states across an unknown maneuver. This representation technique with TFCs enables us to facilitate the analytical propagation of uncertainties of the satellite state. This approach allows for the usage of existing pre-maneuver orbit estimation to compute the orbit solution after the unknown maneuver. In this paper, we applied this approach to orbit determination (OD) problems across unknown maneuvers by appending different combinations of TFCs to the state vector in the batch filter. The aim is to investigate how different maneuver representations with different TFC sets affect the OD solution across unknown maneuvers. Simulation results show that each TFC set provides different representations of the unknown perturbing acceleration, which yields varying magnitudes of delta velocity for a given maneuver. However, OD solutions across unknown maneuvers using different TFC sets display equivalent performance over the post-maneuver arc as long as those TFC sets are capable of generating the apparent secular motion caused by a given unknown maneuver.

  4. Anthracycline-containing chemotherapy causes long-term impairment of mitochondrial respiration and increased reactive oxygen species release in skeletal muscle

    PubMed Central

    Gouspillou, Gilles; Scheede-Bergdahl, Celena; Spendiff, Sally; Vuda, Madhusudanarao; Meehan, Brian; Mlynarski, Heather; Archer-Lahlou, Elodie; Sgarioto, Nicolas; Purves-Smith, Fennigje M.; Konokhova, Yana; Rak, Janusz; Chevalier, Stéphanie; Taivassalo, Tanja; Hepple, Russell T.; Jagoe, R. Thomas

    2015-01-01

    Anticancer treatments for childhood acute lymphoblastic leukaemia (ALL) are highly effective but are now implicated in causing impaired muscle function in long-term survivors. However, no comprehensive assessment of skeletal muscle mitochondrial functions in long-term survivors has been performed and the presence of persistent chemotherapy-induced skeletal muscle mitochondrial dysfunction remains a strong possibility. Non-tumour-bearing mice were treated with two drugs that have been used frequently in ALL treatment (doxorubicin and dexamethasone) for up to 4 cycles at 3-week intervals and euthanized 3 months after the 4th cycle. Treated animals had impaired growth and lower muscle mass as well as reduced mitochondrial respiration and increased reactive oxygen species production per unit oxygen consumption. Mitochondrial DNA content and protein levels of key mitochondrial membrane proteins and markers of mitochondrial biogenesis were unchanged, but protein levels of Parkin were reduced. This suggests a novel pattern of chemotherapy-induced mitochondrial dysfunction in skeletal muscle that persists because of an acquired defect in mitophagy signaling. The results could explain the observed functional impairments in adult survivors of childhood ALL and may also be relevant to long-term survivors of other cancers treated with similar regimes. PMID:25732599

  5. Scaling-up Fermentation of Pichia pastoris to demonstration-scale using new methanol-feeding strategy and increased air pressure instead of pure oxygen supplement

    PubMed Central

    Liu, Wan-Cang; Gong, Ting; Wang, Qing-Hua; Liang, Xiao; Chen, Jing-Jing; Zhu, Ping

    2016-01-01

    Scaling-up of high-cell-density fermentation (HCDF) of Pichia pastoris from the lab or pilot scale to the demonstration scale possesses great significance because the latter is the final technological hurdle in the decision to go commercial. However, related investigations have rarely been reported. In this paper, we study the scaling-up processes of a recombinant P. pastoris from the pilot (10 to 100-L) to the demonstration (1,000-L) scales, which can be used to convert 7-β-xylosyl-10-deacetyltaxol into 10-deacetyltaxol by the β-xylosidase for semi-synthesis of Taxol. We demonstrated that a pure oxygen supplement can be omitted from the HCDF if the super atmospheric pressure was increased from 0.05 to 0.10 ± 0.05 MPa, and we developed a new methanol feeding biomass-stat strategy (0.035 mL/g/h) with 1% dissolved oxygen and 100 g/L initial induction biomass (dry cell weight). The scaling-up was reproducible, and the best results were obtained from the 1,000-L scale, featuring a shorter induction time and the highest enzyme activities and productions, respectively. The specific growth and specific production rates were also determined. This study lays a solid foundation for the commercial preparation of 10-deacetyltaxol through the recombinant yeast. It also provides a successful paradigm for scaling-up HCDF of P. pastoris to the demonstration scale. PMID:26790977

  6. Generalized sensory stimulation of conscious rats increases labeling of oxidative pathways of glucose metabolism when the brain glucose-oxygen uptake ratio rises.

    PubMed

    Dienel, Gerald A; Wang, Robert Y; Cruz, Nancy F

    2002-12-01

    Interpretation of functional metabolic brain images requires understanding of metabolic shifts in working brain. Because the disproportionately higher uptake of glucose compared with oxygen ("aerobic glycolysis") during sensory stimulation is not fully explained by changes in levels of lactate or glycogen, metabolic labeling by [6-14C]glucose was used to evaluate utilization of glucose during brief brain activation. Increased labeling of tricarboxylic acid cycle-derived amino acids, mainly glutamate but also gamma-aminobutyric acid, reflects a rise in oxidative metabolism during aerobic glycolysis. The size of the glutamate, lactate, alanine, and aspartate pools changed during stimulation. Brain lactate was derived from blood-borne glucose and its specific activity was twice that of alanine, revealing pyruvate compartmentation. Glycogen labeling doubled during recovery compared with rest and activation; only 4% to 8% of the total 14C was recovered in lactate plus glycogen. Restoration of glycogen levels was slow, and diversion of glucose from oxidative pathways to restore its level could cause a prolonged reduction of the global O2/glucose uptake ratio. The rise in the brain glucose-oxygen uptake ratio during activation does not simply reflect an upward shift of glycolysis under aerobic conditions; instead, it involves altered fluxes into various (oxidative and biosynthetic) pathways with different time courses.

  7. Maneuvering hydrodynamics of fish and small underwater vehicles.

    PubMed

    Bandyopadhyay, Promode R

    2002-02-01

    The understanding of fish maneuvering and its application to underwater rigid bodies are considered. The goal is to gain insight into stealth. The recent progress made in NUWC is reviewed. Fish morphology suggests that control fins for maneuverability have unique scalar relationships irrespective of their speed type. Maneuvering experiments are carried out with fish that are fast yet maneuverable. The gap in maneuverability between fish and small underwater vehicles is quantified. The hydrodynamics of a dorsal fin based brisk maneuvering device and a dual flapping foil device, as applied to rigid cylindrical bodies, are described. The role of pectoral wings in maneuvering and station keeping near surface waves is discussed. A pendulum model of dolphin swimming is presented to show that body length and tail flapping frequency are related. For nearly neutrally buoyant bodies, Froude number and maneuverability are related. Analysis of measurements indicates that the Strouhal number of dolphins is a constant. The mechanism of discrete and deterministic vortex shedding from oscillating control surfaces has the property of large amplitude unsteady forcing and an exquisite phase dependence, which makes it inherently amenable to active control for precision maneuvering. Theoretical control studies are carried out to demonstrate the feasibility of maneuverability of biologically inspired bodies under surface waves. The application of fish hydrodynamics to the silencing of propulsors is considered. Two strategies for the reduction of radiated noise are developed. The effects of a reduction of rotational rate are modeled. The active cambering of blades made of digitally programmable artificial muscles, and their thrust enhancement, are demonstrated. Next, wake momentum filling is carried out by artificial muscles at the trailing edge of a stator blade of an upstream stator propulsor, and articulating them like a fish tail. A reduction of radiated noise, called blade tonals

  8. Increased mitochondrial emission of reactive oxygen species and calpain activation are required for doxorubicin-induced cardiac and skeletal muscle myopathy.

    PubMed

    Min, Kisuk; Kwon, Oh-Sung; Smuder, Ashley J; Wiggs, Michael P; Sollanek, Kurt J; Christou, Demetra D; Yoo, Jeung-Ki; Hwang, Moon-Hyon; Szeto, Hazel H; Kavazis, Andreas N; Powers, Scott K

    2015-04-15

    Although doxorubicin (DOX) is a highly effective anti-tumour agent used to treat a variety of cancers, DOX administration is associated with significant side effects, including myopathy of both cardiac and skeletal muscles. The mechanisms responsible for DOX-mediated myopathy remain a topic of debate. We tested the hypothesis that both increased mitochondrial reactive oxygen species (ROS) emission and activation of the cysteine protease calpain are required for DOX-induced myopathy in rat cardiac and skeletal muscle. Cause and effect was determined by administering a novel mitochondrial-targeted anti-oxidant to prevent DOX-induced increases in mitochondrial ROS emission, whereas a highly-selective pharmacological inhibitor was exploited to inhibit calpain activity. Our findings reveal that mitochondria are a major site of DOX-mediated ROS production in both cardiac and skeletal muscle fibres and the prevention of DOX-induced increases in mitochondrial ROS emission protects against fibre atrophy and contractile dysfunction in both cardiac and skeletal muscles. Furthermore, our results indicate that DOX-induced increases in mitochondrial ROS emission are required to activate calpain in heart and skeletal muscles and, importantly, calpain activation is a major contributor to DOX-induced myopathy. Taken together, these findings show that increased mitochondrial ROS production and calpain activation are significant contributors to the development of DOX-induced myopathy in both cardiac and skeletal muscle fibres.

  9. Reactive oxygen species production induced by ethanol in Saccharomyces cerevisiae increases because of a dysfunctional mitochondrial iron-sulfur cluster assembly system.

    PubMed

    Pérez-Gallardo, Rocio V; Briones, Luis S; Díaz-Pérez, Alma L; Gutiérrez, Sergio; Rodríguez-Zavala, José S; Campos-García, Jesús

    2013-12-01

    Ethanol accumulation during fermentation contributes to the toxic effects in Saccharomyces cerevisiae, impairing its viability and fermentative capabilities. The iron-sulfur (Fe-S) cluster biogenesis is encoded by the ISC genes. Reactive oxygen species (ROS) generation is associated with iron release from Fe-S-containing enzymes. We evaluated ethanol toxicity, ROS generation, antioxidant response and mitochondrial integrity in S. cerevisiae ISC mutants. These mutants showed an impaired tolerance to ethanol. ROS generation increased substantially when ethanol accumulated at toxic concentrations under the fermentation process. At the cellular and mitochondrial levels, ROS were increased in yeast treated with ethanol and increased to a higher level in the ssq1∆, isa1∆, iba57∆ and grx5∆ mutants - hydrogen peroxide and superoxide were the main molecules detected. Additionally, ethanol treatment decreased GSH/GSSG ratio and increased catalase activity in the ISC mutants. Examination of cytochrome c integrity indicated that mitochondrial apoptosis was triggered following ethanol treatment. The findings indicate that the mechanism of ethanol toxicity occurs via ROS generation dependent on ISC assembly system functionality. In addition, mutations in the ISC genes in S. cerevisiae contribute to the increase in ROS concentration at the mitochondrial and cellular level, leading to depletion of the antioxidant responses and finally to mitochondrial apoptosis. PMID:24028658

  10. Effect of airway inflation pressure on forced expiratory maneuvers from raised lung volume in infants.

    PubMed

    Lum, Sooky; Hoo, Ah-Fong; Stocks, Janet

    2002-02-01

    The raised lung volume technique is increasingly used to measure forced expiratory maneuvers in infants. However, there is no consensus regarding the optimal airway inflation pressure (P(inf)) required for such maneuvers, or the influence of small changes in P(inf) within and between infants. The aim of this study was to assess the effect of small differences (0.2-0.3 kPa) in P(inf) on forced vital capacity (FVC), forced expired volume in 0.5 sec (FEV(0.5)), and forced expired flow at 75% of vital capacity (FEF(75)), all derived from the raised volume rapid thoraco-abdominal compression (RVRTC) technique. Randomized paired forced expiratory maneuvers were obtained in 32 healthy infants ( 3.9-39.3 weeks old, 3.8-9.9 kg) with the safety pressure relief valve for P(inf) set to 2.7 kPa or 3.0 kPa (27 or 30 cm H(2)0). When mean (SD) P(inf) was increased by 8.4 (2.8)%, there was a significant (P < 0.01) increase in mean (SD) FVC, FEV(0.5), and FEF(75) by 5.8 (5.7)%, 6.1 (6)%, and 8.3 (16.2)%, respectively. In conclusion, relatively small differences in P(inf) will result in significant differences in FVC, FEV(0.5), and FEF(75) by RVRTC technique. Precision in setting and reporting the applied P(inf) is therefore essential, particularly if data are to be compared between centers.

  11. A new alpha-globin variant with increased oxygen affinity in a Swiss family: Hb Frauenfeld [alpha 138(H21)Ser-->Phe, TCC>TTC (alpha 2)].

    PubMed

    Hochuli, Michel; Zurbriggen, Karin; Schmid, Marlis; Speer, Oliver; Rochat, Philippe; Frauchiger, Beat; Kleinert, Peter; Schmugge, Markus; Troxler, Heinz

    2009-01-01

    A new alpha-globin mutation [alpha 138(H21)Ser-->Phe] was found in a 55-year-old male proband with an erythrocytosis known since his youth. Cation exchange high performance liquid chromatography (HPLC) revealed an additional peak eluting slightly before Hb A indicating the presence of a variant. The peak area of the variant was approximately one-third that of Hb A suggesting an alpha-globin variant. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry analysis confirmed the mutation at the protein level. The variant is also detectable with isoelectric focusing and reversed phase HPLC. DNA analysis revealed a heterozygous sequence mutation at codon 138 of the alpha2 gene. A C>T transition at the second nucleotide of the codon indicated a Ser-->Phe exchange. The variant showed increased oxygen affinity and was named Hb Frauenfeld.

  12. Retinoic acid-induced differentiation increases the rate of oxygen consumption and enhances the spare respiratory capacity of mitochondria in SH-SY5Y cells.

    PubMed

    Xun, Zhiyin; Lee, Do-Yup; Lim, James; Canaria, Christie A; Barnebey, Adam; Yanonne, Steven M; McMurray, Cynthia T

    2012-04-01

    Retinoic acid (RA) is used in differentiation therapy to treat a variety of cancers including neuroblastoma. The contributing factors for its therapeutic efficacy are poorly understood. However, mitochondria (MT) have been implicated as key effectors in RA-mediated differentiation process. Here we utilize the SH-SY5Y human neuroblastoma cell line as a model to examine how RA influences MT during the differentiation process. We find that RA confers an approximately sixfold increase in the oxygen consumption rate while the rate of glycolysis modestly increases. RA treatment does not increase the number of MT or cause measurable changes in the composition of the electron transport chain. Rather, RA treatment significantly increases the mitochondrial spare respiratory capacity. We propose a competition model for the therapeutic effects of RA. Specifically, the high metabolic rate in differentiated cells limits the availability of metabolic nutrients for use by the undifferentiated cells and suppresses their growth. Thus, RA treatment provides a selective advantage for the differentiated state.

  13. Space shuttle maneuvering engine reusable thrust chamber program. Task 11: Low Epsilon stability test plan

    NASA Technical Reports Server (NTRS)

    Pauckert, R. P.

    1974-01-01

    The performance and heat transfer characteristics of a doublet element type injector for the space shuttle orbiter maneuvering engine thrust chamber were investigated. Ths stability characteristics were evaluated over a range of chamber pressures and mixture ratios. The specific objectives of the test were: (1) to determine whether stability has been influenced by injection of boundary layer coolant across the cavity entrance, (2) if the injector is stable, to determine the minimum cavity area required to maintain stability, and (3) if the injector is unstable, to determine the effects of entrance geometry and increased area on stability.

  14. Synergistic catalytic properties of bifunctional nanoalloy catalysts in rechargeable lithium-oxygen battery

    NASA Astrophysics Data System (ADS)

    Kang, Ning; Ng, Mei Shan; Shan, Shiyao; Wu, Jinfang; Zhao, Wei; Yin, Jun; Fang, Weiqing; Luo, Jin; Petkov, Valeri; Zhong, Chuan-Jian

    2016-09-01

    The understanding of factors influencing the performance of catalysts in the air cathode of a rechargeable lithium-oxygen battery, including overpotentials for oxygen reduction/evolution and discharge capacity, is essential for exploration of its ultimate application. This report describes new findings of an investigation of PdCu nanoalloys as cathode catalysts. Alloying Pd with oxophilic base metals such as Cu leads to reduction of the overpotentials and increase of the discharge capacity. The nanoalloy structures depend on the bimetallic composition, with an atomic ratio near 50:50 featuring mixed bcc and fcc structures. The discharge potential exhibits a maximum while the charge potential display a minimum in the range of 20-50% Cu, closer to 25% Cu, both of which correspond to a maximum reduction of the discharge-charge overpotentials. The discharge capacity displays a gradual increase with Cu%. This type of catalytic synergy is believed to be associated with a combination of ensemble and ligand effects. In particular, the activation of oxygen on Pd sites and oxygen oxophilicity at the alloyed Cu sites in the catalyst may have played an important role in effectively activating oxygen and maneuvering surface superoxide/peroxide species. These findings have implications for the design of multifunctional cathode catalysts in rechargeable lithium-oxygen batteries.

  15. Genomic and non-genomic regulation of PGC1 isoforms by estrogen to increase cerebral vascular mitochondrial biogenesis and reactive oxygen species protection.

    PubMed

    Kemper, Martin F; Stirone, Chris; Krause, Diana N; Duckles, Sue P; Procaccio, Vincent

    2014-01-15

    We previously found that estrogen exerts a novel protective effect on mitochondria in brain vasculature. Here we demonstrate in rat cerebral blood vessels that 17β-estradiol (estrogen), both in vivo and ex vivo, affects key transcriptional coactivators responsible for mitochondrial regulation. Treatment of ovariectomized rats with estrogen in vivo lowered mRNA levels of peroxisome proliferator-activated receptor-γ coactivator-1 alpha (PGC-1α) but increased levels of the other PGC-1 isoforms: PGC-1β and PGC-1 related coactivator (PRC). In vessels ex vivo, estrogen decreased protein levels of PGC-1α via activation of phosphatidylinositol 3-kinase (PI3K). Estrogen treatment also increased phosphorylation of forkhead transcription factor, FoxO1, a known pathway for PGC-1α downregulation. In contrast to the decrease in PGC-1α, estrogen increased protein levels of nuclear respiratory factor 1, a known PGC target and mediator of mitochondrial biogenesis. The latter effect of estrogen was independent of PI3K, suggesting a separate mechanism consistent with increased expression of PGC-1β and PRC. We demonstrated increased mitochondrial biogenesis following estrogen treatment in vivo; cerebrovascular levels of mitochondrial transcription factor A and electron transport chain subunits as well as the mitochondrial/nuclear DNA ratio were increased. We examined a downstream target of PGC-1β, glutamate-cysteine ligase (GCL), the rate-limiting enzyme for glutathione synthesis. In vivo estrogen increased protein levels of both GCL subunits and total glutathione levels. Together these data show estrogen differentially regulates PGC-1 isoforms in brain vasculature, underscoring the importance of these coactivators in adapting mitochondria in specific tissues. By upregulating PGC-1β and/or PRC, estrogen appears to enhance mitochondrial biogenesis, function and reactive oxygen species protection.

  16. Intra-Operative Tissue Oxygen Tension Is Increased by Local Insufflation of Humidified-Warm CO2 during Open Abdominal Surgery in a Rat Model

    PubMed Central

    Marshall, Jean K.; Lindner, Pernilla; Tait, Noel; Maddocks, Tracy; Riepsamen, Angelique; van der Linden, Jan

    2015-01-01

    Introduction Maintenance of high tissue oxygenation (PtO2) is recommended during surgery because PtO2 is highly predictive of surgical site infection and colonic anastomotic leakage. However, surgical site perfusion is often sub-optimal, creating an obstructive hurdle for traditional, systemically applied therapies to maintain or increase surgical site PtO2. This research tested the hypothesis that insufflation of humidified-warm CO2 into the abdominal cavity would increase sub-peritoneal PtO2 during open abdominal surgery. Materials and Methods 15 Wistar rats underwent laparotomy under general anesthesia. Three sets of randomized cross-over experiments were conducted in which the abdominal cavity was subjected to alternating exposure to 1) humidified-warm CO2 & ambient air; 2) humidified-warm CO2 & dry-cold CO2; and 3) dry-cold CO2 & ambient air. Sub-peritoneal PtO2 and tissue temperature were measured with a polarographic oxygen probe. Results Upon insufflation of humidified-warm CO2, PtO2 increased by 29.8 mmHg (SD 13.3; p<0.001), or 96.6% (SD 51.9), and tissue temperature by 3.0°C (SD 1.7 p<0.001), in comparison with exposure to ambient air. Smaller, but significant, increases in PtO2 were seen in experiments 2 and 3. Tissue temperature decreased upon exposure to dry-cold CO2 compared with ambient air (-1.4°C, SD 0.5, p = 0.001). Conclusions In a rat model, insufflation of humidified-warm CO2 into the abdominal cavity during open abdominal surgery causes an immediate and potentially clinically significant increase in PtO2. The effect is an additive result of the delivery of CO2 and avoidance of evaporative cooling via the delivery of the CO2 gas humidified at body temperature. PMID:25835954

  17. Conflicting Physiological and Genomic Cardiopulmonary Effects of Recruitment Maneuvers in Murine Acute Lung Injury

    PubMed Central

    Mekontso Dessap, Armand; Voiriot, Guillaume; Zhou, Tong; Marcos, Elisabeth; Dudek, Steven M.; Jacobson, Jeff R.; Machado, Roberto; Adnot, Serge; Brochard, Laurent; Maitre, Bernard

    2012-01-01

    Low tidal volume ventilation, although promoting atelectasis, is a protective strategy against ventilator-induced lung injury. Deep inflation (DI) recruitment maneuvers restore lung volumes, but potentially compromise lung parenchymal and vascular function via repetitive overdistention. Our objective was to examine cardiopulmonary physiological and transcriptional consequences of recruitment maneuvers. C57/BL6 mice challenged with either PBS or LPS via aspiration were placed on mechanical ventilation (5 h) using low tidal volume inflation (TI; 8 μl/g) alone or in combination with intermittent DIs (0.75 ml twice/min). Lung mechanics during TI ventilation significantly deteriorated, as assessed by forced oscillation technique and pressure–volume curves. DI mitigated the TI-induced alterations in lung mechanics, but induced a significant rise in right ventricle systolic pressures and pulmonary vascular resistances, especially in LPS-challenged animals. In addition, DI exacerbated the LPS-induced genome-wide lung inflammatory transcriptome, with prominent dysregulation of a gene cluster involving vascular processes, as well as increases in cytokine concentrations in bronchoalveolar lavage fluid and plasma. Gene ontology analyses of right ventricular tissue expression profiles also identified inflammatory signatures, as well as apoptosis and membrane organization ontologies, as potential elements in the response to acute pressure overload. Our results, although confirming the improvement in lung mechanics offered by DI, highlight a detrimental impact in sustaining inflammatory response and exacerbating lung vascular dysfunction, events contributing to increases in right ventricle afterload. These novel insights should be integrated into the clinical assessment of the risk/benefit of recruitment maneuver strategies. PMID:22135358

  18. Left Ventricular Transmural Gradient in Mitochondrial Respiration Is Associated with Increased Sub-Endocardium Nitric Oxide and Reactive Oxygen Species Productions

    PubMed Central

    Kindo, Michel; Gerelli, Sébastien; Bouitbir, Jamal; Hoang Minh, Tam; Charles, Anne-Laure; Mazzucotelli, Jean-Philippe; Zoll, Joffrey; Piquard, François; Geny, Bernard

    2016-01-01

    Objective: Left ventricle (LV) transmural gradient in mitochondrial respiration has been recently reported. However, to date, the physiological mechanisms involved in the lower endocardium mitochondrial respiration chain capacity still remain to be determined. Since, nitric oxide (NO) synthase expression in the heart has spatial heterogeneity and might impair mitochondrial function, we investigated a potential association between LV transmural NO and mitochondrial function gradient. Methods: Maximal oxidative capacity (VMax) and relative contributions of the respiratory chain complexes II, III, IV (VSucc) and IV (VTMPD), mitochondrial content (citrate synthase activity), coupling, NO (electron paramagnetic resonance), and reactive oxygen species (ROS) production (H2O2 and dihydroethidium (DHE) staining) were determined in rat sub-endocardium (Endo) and sub-epicardium (Epi). Further, the effect of a direct NO donor (MAHMA NONOate) on maximal mitochondrial respiratory rates (Vmax) was determined. Results: Mitochondrial respiratory chain activities were reduced in the Endo compared with the Epi (−16.92%; P = 0.04 for Vmax and –18.73%; P = 0.02, for Vsucc, respectively). NO production was two-fold higher in the Endo compared with the Epi (P = 0.002) and interestingly, increasing NO concentration reduced Vmax. Mitochondrial H2O2 and LV ROS productions were significantly increased in Endo compared to Epi, citrate synthase activity and mitochondrial coupling being similar in the two layers. Conclusions: LV mitochondrial respiration transmural gradient is likely related to NO and possibly ROS increased production in the sub-endocardium. PMID:27582709

  19. Extracellular vesicles released from cells exposed to reactive oxygen species increase annexin A2 expression and survival of target cells exposed to the same conditions.

    PubMed

    Grindheim, Ann Kari; Vedeler, Anni

    2016-01-01

    Annexin A2 (AnxA2) is present in multiple cellular compartments and interacts with numerous ligands including calcium, proteins, cholesterol, negatively charged phospholipids and RNA. These interactions are tightly regulated by its post-translational modifications. The levels of AnxA2 and its Tyr23 phosphorylated form (pTyr23AnxA2) are increased in many cancers and the protein is involved in malignant cell transformation, metastasis and angiogenesis. Our previous studies of rat pheochromocytoma (PC12) cells showed that reactive oxygen species (ROS) induce rapid, simultaneous and transient dephosphorylation of nuclear AnxA2, most likely associating with PML bodies, while AnxA2 associated with F-actin at the cell cortex undergoes Tyr23 phosphorylation. The pTyr23AnxA2 in the periphery of the cells is incorporated into intraluminal vesicles of multivesicular endosomes and subsequently released to the extracellular space. We show here that extracellular vesicles (EVs) from cells exposed to ROS prime untreated PC12 cells to better tolerate subsequent oxidative stress, thus enhancing their survival. There is an increase in the levels of pTyr23AnxA2 and AnxA2 in the primed cells, suggesting that AnxA2 is involved in their survival. This increase is due to an upregulation of AnxA2 expression both at the transcriptional and translational levels after relatively short term (2 h) exposure to primed EVs. PMID:27574537

  20. Effect of increased cardiac output on liver blood flow, oxygen exchange and metabolic rate during longterm endotoxin-induced shock in pigs

    PubMed Central

    Šantak, Borislav; Radermacher, Peter; Adler, Jens; Iber, Thomas; Rieger, Karen M; Wachter, Ulrich; Vogt, Josef; Georgieff, Michael; Träger, Karl

    1998-01-01

    We investigated hepatic blood flow, O2 exchange and metabolism in porcine endotoxic shock (Control, n=8; Endotoxin, n=10) with administration of hydroxyethylstarch to maintain arterial pressure (MAP)>60 mmHg. Before and 12, 18 and 24 h after starting continuous i.v. endotoxin we measured portal venous and hepatic arterial blood flow, intracapillary haemoglobin O2 saturation (Hb-O2%) of the liver surface and arterial, portal and hepatic venous lactate, pyruvate, glyercol and alanine concentrations. Glucose production rate was derived from the plasma isotope enrichment during infusion of [6,6-2H2]-glucose. Despite a sustained 50% increase in cardiac output endotoxin caused a progressive, significant fall in MAP. Liver blood flow significantly increased, but endotoxin affected neither hepatic O2 delivery and uptake nor mean intracapillary Hb-O2% and Hb-O2% frequency distributions. Endotoxin nearly doubled endogenous glucose production rate while hepatic lactate, alanine and glycerol uptake rates progressively decreased significantly. The lactate uptake rate even became negative (P<0.05 vs Control). Endotoxin caused portal and hepatic venous pH to fall significantly concomitant with significantly increased arterial, portal and hepatic venous lactate/pyruvate ratios. During endotoxic shock increased cardiac output achieved by colloid infusion maintained elevated liver blood flow and thereby macro- and microcirculatory O2 supply. Glucose production rate nearly doubled with complete dissociation of hepatic uptake of glucogenic precursors and glucose release. Despite well-preserved capillary oxygenation increased lactate/pyruvate ratios reflecting impaired cytosolic redox state suggested deranged liver energy balance, possibly due to the O2 requirements of gluconeogenesis. PMID:9756385

  1. Does dragonfly's abdomen flexion help with fast turning maneuvers?

    NASA Astrophysics Data System (ADS)

    Liu, Geng; Li, Chengyu; Dong, Haibo; Flow Simulation Research Group Team

    2013-11-01

    Dragonflies are able to achieve fast turning maneuvers during take-off flights. Both asymmetric wing flapping and abdomen flexion have been observed during the fast turning. It's widely thought that the asymmetric wing beats are responsible of producing the aerodynamic moment needed for the body rotation. However, the dynamic effect of the abdomen flexion is not clear yet. In this study, an integrated experimental and computational approach is used to study the underlying dynamic effect of dragonfly abdomen flexion. It's found that dragonfly abdomen tended to bend towards the same side as the body reorienting to. Quantitative analysis have shown that during take-off turning maneuver the abdomen flexion can modulate the arm of force by changing the position of the center of mass relative to the thorax. As a result, roll and yaw moments produced by the wing flapping can be enhanced. This work is supported by NSF CBET-1313217. This work is supported by NSF CBET-1313217.

  2. Visual display aid for orbital maneuvering - Design considerations

    NASA Technical Reports Server (NTRS)

    Grunwald, Arthur J.; Ellis, Stephen R.

    1993-01-01

    This paper describes the development of an interactive proximity operations planning system that allows on-site planning of fuel-efficient multiburn maneuvers in a potential multispacecraft environment. Although this display system most directly assists planning by providing visual feedback to aid visualization of the trajectories and constraints, its most significant features include: (1) the use of an 'inverse dynamics' algorithm that removes control nonlinearities facing the operator, and (2) a trajectory planning technique that separates, through a 'geometric spreadsheet', the normally coupled complex problems of planning orbital maneuvers and allows solution by an iterative sequence of simple independent actions. The visual feedback of trajectory shapes and operational constraints, provided by user-transparent and continuously active background computations, allows the operator to make fast, iterative design changes that rapidly converge to fuel-efficient solutions. The planning tool provides an example of operator-assisted optimization of nonlinear cost functions.

  3. Heterogeneous Multiple Sensors Joint Tracking of Maneuvering Target in Clutter

    PubMed Central

    Wu, Panlong; Li, Xingxiu; Kong, Jianshou; Liu, Jiale

    2015-01-01

    To solve the problem of tracking maneuvering airborne targets in the presence of clutter, an improved interacting multiple model probability data association algorithm (IMMPDA-MDCM) using radar/IR sensors fusion is proposed. Under the architecture of the proposed algorithm, the radar/IR centralized fusion tracking scheme of IMMPDA-MDCM is designed to guarantee the observability of the target state. The interacting multiple model (IMM) deals with the model switching. The modified debiased converted measurement (MDCM) filter accounts for non-linearity in the dynamic system models, and reduces the effect of measurement noise on the covariance effectively. The probability data association (PDA) handles data association and measurement uncertainties in clutter. The simulation results show that the proposed algorithm can improve the tracking precision for maneuvering target in clutters, and has higher tracking precision than the traditional IMMPDA based on EKF and IMMPDA based on DCM algorithm. PMID:26193279

  4. Guidance law against maneuvering targets with intercept angle constraint.

    PubMed

    Xiong, Shaofeng; Wang, Weihong; Liu, Xiaodong; Wang, Sen; Chen, Zengqiang

    2014-07-01

    This study explores the guidance law against maneuvering targets with the intercept angle constraint. The limitation of the traditional guidance law, which simply treats the unknown target acceleration as zero, has been analyzed. To reduce this limitation, a linear extended state observer is constructed to estimate the acceleration of the maneuvering target to enhance the tracking performance of the desired intercept angle. Furthermore, a nonsingular terminal sliding mode control scheme is adopted to design the sliding surface, which is able to avoid the singularity in the terminal phase of guidance. Simulation results have demonstrated that the proposed guidance law outperforms the traditional guidance law in the sense that more accurate intercept angle can be achieved.

  5. Thermally-Constrained Fuel-Optimal ISS Maneuvers

    NASA Technical Reports Server (NTRS)

    Bhatt, Sagar; Svecz, Andrew; Alaniz, Abran; Jang, Jiann-Woei; Nguyen, Louis; Spanos, Pol

    2015-01-01

    Optimal Propellant Maneuvers (OPMs) are now being used to rotate the International Space Station (ISS) and have saved hundreds of kilograms of propellant over the last two years. The savings are achieved by commanding the ISS to follow a pre-planned attitude trajectory optimized to take advantage of environmental torques. The trajectory is obtained by solving an optimal control problem. Prior to use on orbit, OPM trajectories are screened to ensure a static sun vector (SSV) does not occur during the maneuver. The SSV is an indicator that the ISS hardware temperatures may exceed thermal limits, causing damage to the components. In this paper, thermally-constrained fuel-optimal trajectories are presented that avoid an SSV and can be used throughout the year while still reducing propellant consumption significantly.

  6. Broken-Plane Maneuver Applications for Earth to Mars Trajectories

    NASA Technical Reports Server (NTRS)

    Abilleira, Fernando

    2007-01-01

    Optimization techniques are critical when investigating Earth to Mars trajectories since they have the potential of reducing the total (delta)V of a mission. A deep space maneuver (DSM) executed during the cruise may improve a trajectory by reducing the total mission V. Nonetheless, DSMs not only may improve trajectory performance (from an energetic point of view) but also open up new families of trajectories that would satisfy very specific mission requirements not achievable with ballistic trajectories. In the following pages, various specific examples showing the potential advantages of the usage of broken plane maneuvers will be introduced. These examples correspond to possible scenarios for Earth to Mars trajectories during the next decade (2010-2020).

  7. Optimal Variable-Structure Control Tracking of Spacecraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Crassidis, John L.; Vadali, Srinivas R.; Markley, F. Landis

    1999-01-01

    An optimal control approach using variable-structure (sliding-mode) tracking for large angle spacecraft maneuvers is presented. The approach expands upon a previously derived regulation result using a quaternion parameterization for the kinematic equations of motion. This parameterization is used since it is free of singularities. The main contribution of this paper is the utilization of a simple term in the control law that produces a maneuver to the reference attitude trajectory in the shortest distance. Also, a multiplicative error quaternion between the desired and actual attitude is used to derive the control law. Sliding-mode switching surfaces are derived using an optimal-control analysis. Control laws are given using either external torque commands or reaction wheel commands. Global asymptotic stability is shown for both cases using a Lyapunov analysis. Simulation results are shown which use the new control strategy to stabilize the motion of the Microwave Anisotropy Probe spacecraft.

  8. Single step optimization of manipulator maneuvers with variable structure control

    NASA Technical Reports Server (NTRS)

    Chen, N.; Dwyer, T. A. W., III

    1987-01-01

    One step ahead optimization has been recently proposed for spacecraft attitude maneuvers as well as for robot manipulator maneuvers. Such a technique yields a discrete time control algorithm implementable as a sequence of state-dependent, quadratic programming problems for acceleration optimization. Its sensitivity to model accuracy, for the required inversion of the system dynamics, is shown in this paper to be alleviated by a fast variable structure control correction, acting between the sampling intervals of the slow one step ahead discrete time acceleration command generation algorithm. The slow and fast looping concept chosen follows that recently proposed for optimal aiming strategies with variable structure control. Accelerations required by the VSC correction are reserved during the slow one step ahead command generation so that the ability to overshoot the sliding surface is guaranteed.

  9. Design and analysis of a supersonic penetration/maneuvering fighter

    NASA Technical Reports Server (NTRS)

    Child, R. D.

    1975-01-01

    The design of three candidate air combat fighters which would cruise effectively at freestream Mach numbers of 1.6, 2.0, and 2.5 while maintaining good transonic maneuvering capability, is considered. These fighters were designed to deliver aerodynamically controlled dogfight missiles at the design Mach numbers. Studies performed by Rockwell International in May 1974 and guidance from NASA determined the shape and size of these missiles. The principle objective of this study is the aerodynamic design of the vehicles; however, configurations are sized to have realistic structures, mass properties, and propulsion systems. The results of this study show that air combat fighters in the 15,000 to 23,000 pound class would cruise supersonically on dry power and still maintain good transonic maneuvering performance.

  10. Time efficient spacecraft maneuver using constrained torque distribution

    NASA Astrophysics Data System (ADS)

    Cao, Xibin; Yue, Chengfei; Liu, Ming; Wu, Baolin

    2016-06-01

    This paper investigates the time efficient maneuver of rigid satellites with inertia uncertainty and bounded external disturbance. A redundant cluster of four reaction wheels is used to control the spacecraft. To make full use of the controllability and avoid frequent unload for reaction wheels, a maximum output torque and maximum angular momentum constrained torque distribution method is developed. Based on this distribution approach, the maximum allowable acceleration and velocity of the satellite are optimized during the maneuvering. A novel braking curve is designed on the basis of the optimization strategy of the control torque distribution. A quaternion-based sliding mode control law is proposed to render the state to track the braking curve strictly. The designed controller provides smooth control torque, time efficiency and high control precision. Finally, practical numerical examples are illustrated to show the effectiveness of the developed torque distribution strategy and control methodology.

  11. Dynamic wake distortion model for helicopter maneuvering flight

    NASA Astrophysics Data System (ADS)

    Zhao, Jinggen

    A new rotor dynamic wake distortion model, which can be used to account for the rotor transient wake distortion effect on inflow across the rotor disk during helicopter maneuvering and transitional flight in both hover and forward flight conditions, is developed. The dynamic growths of the induced inflow perturbation across rotor disk during different transient maneuvers, such as a step pitch or roll rate, a step climb rate and a step change of advance ratio are investigated by using a dynamic vortex tube analysis. Based on the vortex tube results, a rotor dynamic wake distortion model, which is expressed in terms of a set of ordinary differential equations, with rotor longitudinal and lateral wake curvatures, wake skew and wake spacing as states, is developed. Also, both the Pitt-Peters dynamic inflow model and the Peters-He finite state inflow model for axial or forward flight are augmented to account for rotor dynamic wake distortion effect during helicopter maneuvering flight. To model the aerodynamic interaction among main rotor, tail rotor and empennage caused by rotor wake curvature effect during helicopter maneuvering flight, a reduced order model based on a vortex tube analysis is developed. Both the augmented Pitt-Peters dynamic inflow model and the augmented Peters-He finite state inflow model, combined with the developed dynamic wake distortion model, together with the interaction model are implemented in a generic helicopter simulation program of UH-60 Black Hawk helicopter and the simulated vehicle control responses in both time domain and frequency domain are compared with flight test data of a UH-60 Black Hawk helicopter in both hover and low speed forward flight conditions.

  12. Differential Evolution Optimization for Targeting Spacecraft Maneuver Plans

    NASA Technical Reports Server (NTRS)

    Mattern, Daniel

    2016-01-01

    Previous analysis identified specific orbital parameters as being safer for conjunction avoidance for the TDRS fleet. With TDRS-9 being considered an at-risk spacecraft, a potential conjunction concern was raised should TDRS-9 fail while at a longitude of 12W. This document summarizes the analysis performed to identify if these specific orbital parameters could be targeted using the remaining drift-termination maneuvers for the relocation of TDRS-9 from 41W longitude to 12W longitude.

  13. Efficient Reorientation Maneuvers for Spacecraft with Multiple Articulated Payloads

    NASA Technical Reports Server (NTRS)

    Mcclamroch, N. Harris

    1993-01-01

    A final report is provided which describes the research program during the period 3 Mar. 1992 to 3 Jun. 1993. A summary of the technical research questions that were studied and of the main results that were obtained is given. The specific outcomes of the research program, including both educational impacts as well as research publications, are listed. The research is concerned with efficient reorientation maneuvers for spacecraft with multiple articulated payloads.

  14. 14 CFR 25.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... factor n for any speed up to Vn may not be less than 2.1+24,000/ (W +10,000) except that n may not be less than 2.5 and need not be greater than 3.8—where W is the design maximum takeoff weight. (c) The negative limit maneuvering load factor— (1) May not be less than −1.0 at speeds up to V C; and (2)...

  15. 14 CFR 25.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... factor n for any speed up to Vn may not be less than 2.1+24,000/ (W +10,000) except that n may not be less than 2.5 and need not be greater than 3.8—where W is the design maximum takeoff weight. (c) The negative limit maneuvering load factor— (1) May not be less than −1.0 at speeds up to V C; and (2)...

  16. A Summary of the Pioneer 10 Maneuver Strategy

    NASA Technical Reports Server (NTRS)

    Frauenholz, R. B.; Ball, J. E.

    1972-01-01

    The Pioneer Project placed a number of interesting and precise requirements on the navigation of the Pioneer 10 spacecraft flyby mission to Jupiter during 1972-1973. To satisfy these requirements the Pioneer navigation team employed a number of versatile computer programs to evaluate the strategies and maneuver sequences required to execute midcourse corrections. The Pioneer 10 mission objectives and the midcourse strategies used to satisfy these objectives are summarized.

  17. Stability and control of maneuvering high-performance aircraft

    NASA Technical Reports Server (NTRS)

    Stengel, R. F.; Berry, P. W.

    1977-01-01

    The stability and control of a high-performance aircraft was analyzed, and a design methodology for a departure prevention stability augmentation system (DPSAS) was developed. A general linear aircraft model was derived which includes maneuvering flight effects and trim calculation procedures for investigating highly dynamic trajectories. The stability and control analysis systematically explored the effects of flight condition and angular motion, as well as the stability of typical air combat trajectories. The effects of configuration variation also were examined.

  18. Flow Modulation and Force Control in Insect Fast Maneuver

    NASA Astrophysics Data System (ADS)

    Li, Chengyu; Dong, Haibo; Zhang, Wen; Gai, Kuo

    2012-11-01

    In this work, an integrated study combining high-speed photogrammetry and direct numerical simulation (DNS) is used to study free flying insects in fast maneuver. Quantitative measurement has shown the significant differences between quad-winged flyers such as dragonfly and damselfly and two-winged flyers such as cicada. Comparisons of unsteady 3D vortex formation and associated aerodynamic force production reveal the different mechanisms used by insects in fast turn. This work is supported by NSF CBET-1055949.

  19. An increase in reactive oxygen species by dietary fish oil coupled with the attenuation of antioxidant defenses by dietary pectin enhances rat colonocyte apoptosis.

    PubMed

    Sanders, Lisa M; Henderson, Cara E; Hong, Mee Young; Barhoumi, Rola; Burghardt, Robert C; Wang, Naisyin; Spinka, Christine M; Carroll, Raymond J; Turner, Nancy D; Chapkin, Robert S; Lupton, Joanne R

    2004-12-01

    We showed previously that the dietary combination of fish oil, rich in (n-3) fatty acids, and the fermentable fiber pectin enhances colonocyte apoptosis in a rat model of experimentally induced colon cancer. In this study, we propose that the mechanism by which this dietary combination heightens apoptosis is via modulation of the colonocyte redox environment. Male Sprague-Dawley rats (n = 60) were fed 1 of 2 fats (corn oil or fish oil) and 1 of 2 fibers (cellulose or pectin) for 2 wk before determination of reactive oxygen species (ROS), oxidative DNA damage, antioxidant enzyme activity [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx)] and apoptosis in isolated colonocytes. Fish oil enhanced ROS, whereas the combination of fish oil and pectin suppressed SOD and CAT and enhanced the SOD/CAT ratio compared with a corn oil and cellulose diet. Despite this modulation to a seemingly prooxidant environment, oxidative DNA damage was inversely related to ROS in the fish oil and pectin diet, and apoptosis was enhanced relative to other diets. Furthermore, apoptosis increased exponentially as ROS increased. These results suggest that the enhancement of apoptosis associated with fish oil and pectin feeding may be due to a modulation of the redox environment that promotes ROS-mediated apoptosis.

  20. Upregulation of NAD(P)H oxidase 1 in hypoxia activates hypoxia-inducible factor 1 via increase in reactive oxygen species.

    PubMed

    Goyal, Parag; Weissmann, Norbert; Grimminger, Friedrich; Hegel, Cornelia; Bader, Lucius; Rose, Frank; Fink, Ludger; Ghofrani, Hossein A; Schermuly, Ralph T; Schmidt, Harald H H W; Seeger, Werner; Hänze, Jörg

    2004-05-15

    Hypoxia sensing and related signaling events, including activation of hypoxia-inducible factor 1 (HIF-1), represent key features in cell physiology and lung function. Using cultured A549 cells, we investigated the role of NAD(P)H oxidase 1 (Nox1), suggested to be a subunit of a low-output NAD(P)H oxidase complex, in hypoxia signaling. Nox1 expression was detected on both the mRNA and protein levels. Upregulation of Nox1 mRNA and protein occurred during hypoxia, accompanied by enhanced reactive oxygen species (ROS) generation. A549 cells, which were transfected with a Nox1 expression vector, revealed an increase in ROS generation accompanied by activation of HIF-1-dependent target gene expression (heme oxygenase 1 mRNA, hypoxia-responsive-element reporter gene activity). In A549 cells stably overexpressing Nox1, accumulation of HIF-1alpha in normoxia and an additional increase in hypoxia were noted. Interference with ROS metabolism by the flavoprotein inhibitor diphenylene iodonium (DPI) and catalase inhibited HIF-1 induction. This suggests that H2O2 links Nox1 and HIF-1 activation. We conclude that hypoxic upregulation of Nox1 and subsequently augmented ROS generation may activate HIF-1-dependent pathways.

  1. Effect of the increase in the entrance convergent section length of the gun nozzle on the high-velocity oxygen fuel and cold spray process

    NASA Astrophysics Data System (ADS)

    Sakaki, K.; Shimizu, Y.

    2001-09-01

    Nozzle geometry, which influences combustion gas dynamics and, therefore, sprayed particle behavior, is one of the most important parameters in the high-velocity oxygen-fuel (HVOF) thermal spray process. The nozzle geometry is also important in the cold spray method. The gas flows in the entrance convergent section of the nozzle exhibit a relatively higher temperature and are subsonic; thus, this region is most suitable for heating spray particles. In this study, numerical simulation and experiments investigated the effect of the entrance geometry of the gun nozzle on the HVOF process. The process changes inside the nozzle, as obtained by numerical simulation studies, were related to the coating properties. An Al2O3-40 mass% TiO2 powder was used for the experimental studies. The change in entrance convergent section length (rather than barrel part length or total length) of the gun nozzle had a significant effect on the deposition efficiency, microstructure, and hardness. The deposition efficiency and hardness increased as this geometry increased. On the other hand, the calculated and measured particle velocity showed a slight decrease. This effect on the HVOF process will also be applied to the nozzle design for the cold spray method.

  2. Photosensitizers neutral red (type I) and rose bengal (type II) cause light-dependent toxicity in Chlamydomonas reinhardtii and induce the Gpxh gene via increased singlet oxygen formation.

    PubMed

    Fischer, Beat B; Krieger-Liszkay, Anja; Eggen, Rik L

    2004-12-01

    The connection between the mode of toxic action and the genetic response caused by the type I photosensitizer and photosynthesis inhibitor neutral red (NR) and the type II photosensitizer rose bengal (RB) was investigated in the green alga Chlamydomonas reinhardtii. For both photosensitizers, a light intensity-dependent increase in toxicity and expression of the glutathione peroxidase homologous gene (Gpxh) was found. The toxicity of RB was reduced by the singlet oxygen (1O2) quenchers 1,4-diazabicyclo[2.2.2]octane and L-histidine, and the RB-induced Gpxh expression was stimulated in deuterium oxide-supplemented growth medium. These observations clearly indicate the involvement of 1O2 in both toxicity and the genetic response caused by RB. NR up-regulated the expression of typical oxidative and general stress response genes, probably by a type I mechanism, and also strongly induced the Gpxh expression. The stimulating effect of deuterium oxide in the growth medium suggested the involvement of 1O2 also in the NR-induced response. Indeed, an increased 1O2 formation was detected with EPR-spin trapping in NR-treated spinach thylakoids. However, none of the 102 quenchers could reduce the light-dependent toxicity of NR in C. reinhardtii, indicating that NR has a different mode of toxic action than RB.

  3. Insights on the antitumor effects of kahweol on human breast cancer: Decreased survival and increased production of reactive oxygen species and cytotoxicity

    SciTech Connect

    Cárdenas, Casimiro; Quesada, Ana R.; Medina, Miguel Ángel

    2014-05-09

    Highlights: • Kahweol inhibits growth and attachment-independent proliferation of tumor cells. • Kahweol induces apoptosis in MDA-MB231 human breast cancer cells. • Kahweol-induced apoptosis involves caspase activation and cytochrome c release. • Kahweol does not protect against hydrogen peroxide cytotoxicity. • Kahweol increases hydrogen peroxide production by human breast cancer cells. - Abstract: The present study aims to identify the modulatory effects of kahweol, an antioxidant diterpene present in coffee beans, on a panel of human tumor cell lines. Kahweol inhibits tumor cell proliferation and clonogenicity and induces apoptosis in several kinds of human tumor cells. In the estrogen receptor-negative MDA-MB231 human breast cancer, the mentioned effects are accompanied by caspases 3/7 and 9 activation and cytochrome c release. On the other hand, kahweol increases the production of reactive oxygen species and their cytotoxicity in human breast cancer cells but not in normal cells. Taken together, our data suggest that kahweol is an antitumor compound with inhibitory effects on tumor cell growth and survival, especially against MDA-MB231 breast cancer cells.

  4. Optimal scheduling of multispacecraft refueling based on cooperative maneuver

    NASA Astrophysics Data System (ADS)

    Du, Bingxiao; Zhao, Yong; Dutta, Atri; Yu, Jing; Chen, Xiaoqian

    2015-06-01

    The scheduling of multispacecraft refueling based on cooperative maneuver in a circular orbit is studied in this paper. In the proposed scheme, both of the single service vehicle (SSV) and the target satellite (TS) perform the orbital transfer to complete the rendezvous at the service places. When a TS is refueled by the SSV, it returns to its original working slot to continue its normal function. In this way, the SSV refuels the TS one by one. A MINLP model for the mission is first built, then a two-level hybrid optimization approach is proposed for determining the strategy, and the optimal solution is successfully obtained by using an algorithm which is a combination of Multi-island Genetic Algorithm and Sequential Quadratic Programming. Results show the cooperative strategy can save around 27.31% in fuel, compared with the non-cooperative strategy in which only the SSV would maneuver in the example considered. Three conclusions can be drawn based on the numerical simulations for the evenly distributed constellations. Firstly, in the cooperative strategy one of the service positions is the initial location of the SSV, other service positions are also target slots, i.e. not all targets need to maneuver, and there may be more than one TS serviced in a given service position. Secondly, the efficiency gains for the cooperative strategy are higher for larger transferred fuel mass. Thirdly, the cooperative strategy is less efficient for targets with larger spacecraft mass.

  5. Control integration concept for hypersonic cruise-turn maneuvers

    NASA Technical Reports Server (NTRS)

    Raney, David L.; Lallman, Frederick J.

    1992-01-01

    Piloting difficulties associated with conducting aircraft maneuvers in hypersonic flight are caused in part by the nonintuitive nature of the aircraft response and the stringent constraints anticipated on allowable angle of attack and dynamic pressure variations. An approach is documented that provides precise, coordinated maneuver control during excursions from a hypersonic cruise flight path and the necessary flight condition constraints. The approach is to achieve specified guidance commands by resolving altitude and cross range errors into a load factor and bank angle command by using a coordinate transformation that acts as an interface between outer and inner loop flight controls. This interface, referred to as a 'resolver', applies constraints on angle of attack and dynamic pressure perturbations while prioritizing altitude regulation over cross range. An unpiloted test simulation, in which the resolver was used to drive inner loop flight controls, produced time histories of responses to guidance commands and atmospheric disturbances at Mach numbers of 6, 10, 15, and 20. Angle of attack and throttle perturbation constraints, combined with high speed flight effects and the desire to maintain constant dynamic pressure, significantly impact the maneuver envelope for a hypersonic vehicle.

  6. Capturing and analyzing wheelchair maneuvering patterns with mobile cloud computing.

    PubMed

    Fu, Jicheng; Hao, Wei; White, Travis; Yan, Yuqing; Jones, Maria; Jan, Yih-Kuen

    2013-01-01

    Power wheelchairs have been widely used to provide independent mobility to people with disabilities. Despite great advancements in power wheelchair technology, research shows that wheelchair related accidents occur frequently. To ensure safe maneuverability, capturing wheelchair maneuvering patterns is fundamental to enable other research, such as safe robotic assistance for wheelchair users. In this study, we propose to record, store, and analyze wheelchair maneuvering data by means of mobile cloud computing. Specifically, the accelerometer and gyroscope sensors in smart phones are used to record wheelchair maneuvering data in real-time. Then, the recorded data are periodically transmitted to the cloud for storage and analysis. The analyzed results are then made available to various types of users, such as mobile phone users, traditional desktop users, etc. The combination of mobile computing and cloud computing leverages the advantages of both techniques and extends the smart phone's capabilities of computing and data storage via the Internet. We performed a case study to implement the mobile cloud computing framework using Android smart phones and Google App Engine, a popular cloud computing platform. Experimental results demonstrated the feasibility of the proposed mobile cloud computing framework.

  7. An Autonomous Onboard Targeting Algorithm Using Finite Thrust Maneuvers

    NASA Technical Reports Server (NTRS)

    Scarritt, Sara K.; Marchand, Belinda G.; Weeks, Michael W.

    2009-01-01

    In earlier investigations, the adaptation and implementation of a modified two-level corrections process as the onboard targeting algorithm for the Trans-Earth Injection phase of Orion is presented. The objective of that targeting algorithm is to generate the times of ignition and magnitudes of the required maneuvers such that the desired state at entry interface is achieved. In an actual onboard flight software implementation, these times of ignition and maneuvers are relayed onto Flight Control for command and execution. Although this process works well when the burn durations or burn arcs are small, this might not be the case during a contingency situation when lower thrust engines are employed to perform the maneuvers. Therefore, a new version of the modified two-level corrections process is formulated to handle the case of finite burn arcs. This paper presents the development and formulation of that finite burn modified two-level corrections process which can again be used as an onboard targeting algorithm for the Trans-Earth Injection phase of Orion. Additionally, performance results and a comparison between the two methods are presented. The finite burn two-level corrector formulation presented here ensures the entry constraints at entry interface are still met without violating the available fuel budget, while still accounting for much longer burn times in its design.

  8. An Autonomous Onboard Targeting Algorithm Using Finite Thrust Maneuvers

    NASA Technical Reports Server (NTRS)

    Scarritt, Sara K.; Marchand, Belinda G.; Brown, Aaron J.; Tracy, William H.; Weeks, Michael W.

    2010-01-01

    In earlier investigations, the adaptation and implementation of a modified two-level corrections (or targeting) process as the onboard targeting algorithm for the Trans-Earth Injection phase of Orion is presented. The objective of that targeting algorithm is to generate the times of ignition and magnitudes of the required maneuvers such that the desired state at entry interface is achieved. In an actual onboard flight software implementation, these times of ignition and maneuvers are relayed onto Flight Control for command and execution. Although this process works well when the burn durations or burn arcs are small, this might not be the case during a contingency situation when lower thrust engines are employed to perform the maneuvers. Therefore, a new model for the two-level corrections process is formulated here to accommodate finite burn arcs. This paper presents the development and formulation of the finite burn two-level corrector, used as an onboard targeting algorithm for the Trans-Earth Injection phase of Orion. A performance comparison between the impulsive and finite burn models is also presented. The present formulation ensures all entry constraints are met, without violating the available fuel budget, while allowing for low-thrust scenarios with long burn durations.

  9. Closed-Loop Aerodynamic Flow Control of a Maneuvering Airfoil

    NASA Astrophysics Data System (ADS)

    Brzozowski, Daniel P.; Culp, John R.; Glezer, Ari

    2011-11-01

    The unsteady interaction between trailing edge aerodynamic flow control and airfoil motion in pitch and plunge is investigated in wind tunnel experiments using a 2-DOF traverse which enables application of time-dependent external torque and forces by servo motors. The global aerodynamic forces and moments are regulated by controlling vorticity generation and accumulation near the surface using hybrid synthetic jet actuators. The dynamic coupling between the actuation and the time-dependent flow field is characterized using simultaneous force and velocity measurements that are taken phase-locked to the commanded actuation waveform. The effect of the unsteady motion on the model-embedded flow control is assessed in unsteady several maneuvers. Circulation time history that is estimated from a PIV wake survey shows that the entire flow over the airfoil readjusts within about 1.5 TCONV, which is about two orders of magnitude shorter than the characteristic time associated with the controlled maneuver of the wind tunnel model. This illustrates that flow-control actuation can be typically effected on time scales that are commensurate with the flow's convective time scale, and that the maneuver response is primarily limited by the inertia of the platform.

  10. PM Science Working Group Meeting on Spacecraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.

    1997-01-01

    The EOS PM Science Working Group met on May 6, 1997, to examine the issue of spacecraft maneuvers. The meeting was held at NASA Goddard Space Flight Center and was attended by the Team Leaders of all four instrument science teams with instruments on the PM-1 spacecraft, additional representatives from each of the four teams, the PM Project management, and random others. The meeting was chaired by the PM Project Scientist and open to all. The meeting was called in order to untangle some of the concerns raised over the past several months regarding whether or not the PM-1 spacecraft should undergo spacecraft maneuvers to allow the instruments to obtain deep-space views. Two of the Science Teams, those for the Moderate-Resolution Imaging Spectroradiometer (MODIS) and the Clouds and the Earth's Radiant Energy System (CERES), had strongly expressed the need for deep-space views in order to calibrate their instruments properly and conveniently. The other two teams, those for the Advanced Microwave Scanning Radiometer (AMSR-E) and the Atmospheric Infrared Sounder (AIRS), the Advanced Microwave Sounding Unit (AMSU), and the Humidity Sounder for Brazil (HSB), had expressed concerns that the maneuvers involve risks to the instruments and undesired gaps in the data sets.

  11. Trajectory Control of Rendezvous with Maneuver Target Spacecraft

    NASA Technical Reports Server (NTRS)

    Zhou, Zhinqiang

    2012-01-01

    In this paper, a nonlinear trajectory control algorithm of rendezvous with maneuvering target spacecraft is presented. The disturbance forces on the chaser and target spacecraft and the thrust forces on the chaser spacecraft are considered in the analysis. The control algorithm developed in this paper uses the relative distance and relative velocity between the target and chaser spacecraft as the inputs. A general formula of reference relative trajectory of the chaser spacecraft to the target spacecraft is developed and applied to four different proximity maneuvers, which are in-track circling, cross-track circling, in-track spiral rendezvous and cross-track spiral rendezvous. The closed-loop differential equations of the proximity relative motion with the control algorithm are derived. It is proven in the paper that the tracking errors between the commanded relative trajectory and the actual relative trajectory are bounded within a constant region determined by the control gains. The prediction of the tracking errors is obtained. Design examples are provided to show the implementation of the control algorithm. The simulation results show that the actual relative trajectory tracks the commanded relative trajectory tightly. The predicted tracking errors match those calculated in the simulation results. The control algorithm developed in this paper can also be applied to interception of maneuver target spacecraft and relative trajectory control of spacecraft formation flying.

  12. Global Precipitation Measurement (GPM) Orbit Design and Autonomous Maneuvers

    NASA Technical Reports Server (NTRS)

    Folta, David; Mendelsohn, Chad; Mailhe, Laurie

    2003-01-01

    The NASA Goddard Space Flight Center's Global Precipitation Measurement (GPM) mission must meet the challenge of measuring worldwide precipitation every three hours. The GPM core spacecraft, part of a constellation, will be required to maintain a circular orbit in a high drag environment at a near-critical inclination. Analysis shows that a mean orbit altitude of 407 km is necessary to prevent ground track repeating. Combined with goals to minimize maneuver operation impacts to science data collection and to enable reasonable long-term orbit predictions, the GPM project has decided to fly the GSFC autonomous maneuver system, AutoCon(TM). This system is a follow-up version of the highly successful New Millennium Program technology flown onboard the Earth Observing-1 formation flying mission. This paper presents the driving science requirements and goals of the GPM mission and shows how they will be met. Selection of the mean semi-major axis, eccentricity, and the AV budget for several ballistic properties are presented. The architecture of the autonomous maneuvering system to meet the goals and requirements is presented along with simulations using GPM parameters. Additionally, the use of the GPM autonomous system to mitigate possible collision avoidance and to aid other spacecraft systems during navigation outages is explored.

  13. Severe Turbulence and Maneuvering from Airline Flight Records

    NASA Technical Reports Server (NTRS)

    Wingrove, Rodney C.; Bach, R. E., Jr.

    1994-01-01

    Digital flight records from reported clear-air turbulence incidents are used to determine winds and turbulence, to determine maneuver g loads, and to analyze control problems. Many cases of severe turbulence are found downwind of mountains and thunderstorms where sharp, sudden jolts are associated with vortices in atmospheric waves. Other cases of severe turbulence are round in strong updrafts above thunderstorm buildups that may be undetected by onboard weather radar. An important finding is that there are large maneuvering loads in over half of the reported clear-air turbulence incidents. Maneuvering loads are determined through an analysis of the short-term variations in elevator deflection and aircraft pitch angle. For altitude control in mountain waves the results indicate that small pitch angle changes with proper timing are sufficient to counter variations in vertical wind. For airspeed control in strong mountain waves, however, there is neither the available thrust nor the quickness in engine response necessary to counter the large variations in winds.

  14. Aerodynamic role of dynamic wing morphing in hummingbird maneuvering flight

    NASA Astrophysics Data System (ADS)

    Ren, Yan; Shallcross, Gregory; Dong, Haibo; Deng, Xinyan; Tobalske, Bret; Flow Simulation Research Group Team; Bio-robotics lab Collaboration; University of Montana Flight Laboratory Collaboration

    2014-11-01

    The flexibility and deformation of hummingbird wing gives hummingbird a great degree of control over fluid forces in flapping flight. Unlike insect wing's passive deformation, hummingbird wing employs a more complicated wing morphing mechanism through both active muscle control and passive feather-air interaction, which results in highly complex 3D wing topology variations during the unsteady flight. Three camera high speed (1000 fps) high resolution digital video was taken and digitized to measure 3D wing conformation in all its complexity during steady flying and maneuvering. Results have shown that the dynamic wing morphing is more prominent in maneuvering flight. Complicated cambering and twisting patterns are observed along the wing pitching axis. A newly developed immersed boundary method which realistically models wing-joint-body of the hummingbird is then employed to simulate the flow associated with dynamic morphing. The simulations provide a first of its kind glimpse of the fluid and vortex dynamics associated with dynamic wing morphing and aerodynamic force computations allow us to gain a better understanding of force producing mechanisms in hummingbird maneuvering flight. This work is supported by AFOSR FA9550-12-1-007 and NSF CEBT-1313217.

  15. Acute ascorbic acid ingestion increases skeletal muscle blood flow and oxygen consumption via local vasodilation during graded handgrip exercise in older adults

    PubMed Central

    Richards, Jennifer C.; Crecelius, Anne R.; Larson, Dennis G.

    2015-01-01

    Human aging is associated with reduced skeletal muscle perfusion during exercise, which may be a result of impaired endothelium-dependent dilation and/or attenuated ability to blunt sympathetically mediated vasoconstriction. Intra-arterial infusion of ascorbic acid (AA) increases nitric oxide-mediated vasodilation and forearm blood flow (FBF) during handgrip exercise in older adults, yet it remains unknown whether an acute oral dose can similarly improve FBF or enhance the ability to blunt sympathetic vasoconstriction during exercise. We hypothesized that 1) acute oral AA would improve FBF (Doppler ultrasound) and oxygen consumption (V̇o2) via local vasodilation during graded rhythmic handgrip exercise in older adults (protocol 1), and 2) AA ingestion would not enhance sympatholysis in older adults during handgrip exercise (protocol 2). In protocol 1 (n = 8; 65 ± 3 yr), AA did not influence FBF or V̇o2 during rest or 5% maximal voluntary contraction (MVC) exercise, but increased FBF (199 ± 13 vs. 248 ± 16 ml/min and 343 ± 24 vs. 403 ± 33 ml/min; P < 0.05) and V̇o2 (26 ± 2 vs. 34 ± 3 ml/min and 43 ± 4 vs. 50 ± 5 ml/min; P < 0.05) at both 15 and 25% MVC, respectively. The increased FBF was due to elevations in forearm vascular conductance (FVC). In protocol 2 (n = 10; 63 ± 2 yr), following AA, FBF was similarly elevated during 15% MVC (∼20%); however, vasoconstriction to reflex increases in sympathetic activity during −40 mmHg lower-body negative pressure at rest (ΔFVC: −16 ± 3 vs. −16 ± 2%) or during 15% MVC (ΔFVC: −12 ± 2 vs. −11 ± 4%) was unchanged. Our collective results indicate that acute oral ingestion of AA improves muscle blood flow and V̇o2 during exercise in older adults via local vasodilation. PMID:25980023

  16. Increased reactive oxygen species and exhaustion of quiescent CD34-positive bone marrow cells may contribute to poor graft function after allotransplants

    PubMed Central

    Hu, Yue; Shi, Min-Min; Wang, Yu-Tong; Wang, Yu; Zhang, Xiao-Hui; Xu, Lan-Ping; Liu, Kai-Yan; Deng, Hong-Kui; Huang, Xiao-Jun

    2016-01-01

    Poor graft function (PGF) is a fatal complication following allogeneic haematopoietic stem cell transplantation. However, the underlying mechanism is unclear. Effective cross-talk between haematopoietic stem cells (HSCs) and bone marrow microenvironment is important for normal haematopoiesis. Normal HSCs reside in a hypoxic bone marrow microenvironment that protects them from oxidative stress that would otherwise inhibit their self-renewal and results in bone marrow failure. Whether an increased level of reactive oxygen species (ROS) causes PGF following allotransplant is unclear. Using a prospective case-pair study, we identified increased levels of ROS in CD34+ bone marrow cells in subjects with PGF. Elevated ROS levels was associated with an increased frequency of DNA strand breaks, apoptosis, exhaustion of quiescent CD34+ cells and defective colony-forming unit plating efficiency, particularly in the CD34+CD38− fraction. Up-regulated intracellular p53, p21, caspase-3 and caspase-9 levels (but not p38) were detected in CD34+ cells, particularly in the CD34+CD38− fraction. To further study the potential role of ROS levels in post-transplant haematopoiesis, CD34+ bone marrow cells from subjects with good graft function were treated with H2O2. This increased ROS levels resulting in defective CD34+ cells, an effect partially reversed by N-acetyl-L-cysteine. Moreover, CD34+ bone marrow cells from the donors to subjects with poor or good graft function exhibited comparable haematopoietic reconstitution capacities in the xeno-transplanted NOD-PrkdcscidIL2rgnull mice. Thus, even if the transplanted donors' bone marrow CD34+ cells are functionally normal pre-transplant, ROS-induced apoptosis may contribute to the exhaustion of CD34+ bone marrow cells in subjects with PGF following allotransplant. PMID:27105530

  17. Propiconazole increases reactive oxygen species levels in mouse hepatic cells in culture and in mouse liver by a cytochrome P450 enzyme mediated process.

    PubMed

    Nesnow, Stephen; Grindstaff, Rachel D; Lambert, Guy; Padgett, William T; Bruno, Maribel; Ge, Yue; Chen, Pei-Jen; Wood, Charles E; Murphy, Lynea

    2011-10-15

    Propiconazole induces hepatocellular carcinomas and hepatocellular adenomas in mice and promotes liver tumors in rats. Transcriptional, proteomic, metabolomic and biochemical studies of hepatic tissues from mice treated with propiconazole under the conditions of the chronic bioassay indicated that propiconazole induced oxidative stress. Here we sought to identify the source of the reactive oxygen species (ROS) induced by propiconazole using both AML12 immortalized mouse hepatocytes in culture and liver tissues from mice. We also sought to further characterize the nature and effects of ROS formation induced by propiconazole treatment in mouse liver. ROS was induced in AML12 cells by propiconazole as measured by fluorescence detection and its formation was ameliorated by N-acetylcysteine. Propiconazole induced glutathione-S-transferase (GSTα) protein levels and increased the levels of thiobarbituric acid reactive substances (TBARS) in AML12 cells. The TBARS levels were decreased by diphenylene iodonium chloride (DPIC), a cytochrome P450 (CYP) reductase inhibitor revealing the role of CYPs in ROS generation. It has been previously reported that Cyp2b and Cyp3a proteins were induced in mouse liver by propiconazole and that Cyp2b and Cyp3a proteins undergo uncoupling of their CYP catalytic cycle releasing ROS. Therefore, salicylic acid hydroxylation was used as probe for ROS formation using microsomes from mice treated with propiconazole. These studies showed that levels of 2,3-dihydroxybenzoic acid (an ROS derived metabolite) were decreased by ketoconazole, melatonin and DPIC. In vivo, propiconazole increased hepatic malondialdehyde levels and GSTα protein levels and had no effect on hepatic catalase or superoxide dismutase activities. Based on these observations we conclude that propiconazole induces ROS in mouse liver by increasing CYP protein levels leading to increased ROS levels. Our data also suggest that propiconazole induces the hydroxyl radical as a major

  18. CELL RESPIRATION STUDIES : II. A COMPARATIVE STUDY OF THE OXYGEN CONSUMPTION OF BLOOD FROM NORMAL INDIVIDUALS AND PATIENTS WITH INCREASED LEUCOCYTE COUNTS (SEPSIS; CHRONIC MYELOGENOUS LEUCEMIA).

    PubMed

    Daland, G A; Isaacs, R

    1927-06-30

    1. The oxygen consumption of blood of normal individuals, when the hemoglobin is saturated with oxygen, is practically zero within the limits of experimental error of the microspirometer used. 2. The oxygen consumed in a microspirometer by the blood of patients with chronic myelogenous leucemia with a high white blood cell count, and of one with leucocytosis from sepsis, was proportional to the number of adult polymorphonuclear neutrophils in the blood. 3. No correlation could be made between the rate of oxygen absorption and the total number of white blood cells in the blood, or the total number of immature cells, or the number of red blood cells, or the amount of oxyhemoglobin. 4. The blood of patients with chronic myelogenous leucemia continued to use oxygen in the microspirometer longer than that of normal individuals, and the hemoglobin, in the leucemic bloods, became desaturated even though exposed to air. 5. In blood in which the bulk. of the cells were immature and the mature cells few, the oxygen consumption was lower than in blood in which the mature cells predominated. The rate of oxygen consumption of the immature cells was relatively low as compared to the mature. 6. The slower rate of oxygen absorption by the immature leucocytes in chronic myelogenous leucemia as compared to the mature cells, places them, in accord with Warburg's reports, in the class of the malignant tissues in this respect rather than in the group of young or embryonic cells.

  19. Biomechanical analysis of stresses to the fifth metatarsal bone during sports maneuvers: implications for fifth metatarsal fractures.

    PubMed

    Orendurff, Michael S; Rohr, Eric S; Segal, Ava D; Medley, Jonathan W; Green, John R; Kadel, Nancy J

    2009-06-01

    Fifth metatarsal stress fractures are an increasing problem in elite and recreational athletic populations. One possible mechanism of injury is the many bending moments applied to the fifth metatarsal during dynamic sports maneuvers involving rapid changes in direction and speed. A potentially important bending moment is loading of the base versus the head of the fifth metatarsal, which tends to cause a bending moment along the bone. To determine which maneuver applies the greatest pressure differential between the base and head of the fifth metatarsal, 10 college-aged male athletes performed running straight, jump take-off, jump landing, cutting right, cutting left, and accelerating while plantar pressures were recorded using a Pedar insole system (Novel Electronics, Inc., St. Paul, MN). Peak pressure at the fifth metatarsal base was subtracted from the peak pressure at the fifth metatarsal head to obtain the fifth metatarsal pressure differential-a corollary to the bending moment. The greatest fifth metatarsal pressure differential was observed during acceleration maneuvers (20 + or - 13.1 N/cm(2); P < 0.0001) followed by running straight (11.6 + or - 8 N/cm(2); P < 0.0008). The other maneuvers had low pressure differentials: jump take-off (4.2 + or - 10.6 N/cm(2)), jump landing (3.7 + or - 9.2 N/cm(2)), cutting left (2.3 + or - 4.2 N/cm(2)), and cutting right (-2.1 + or - 10 N/cm(2)). It appears that acceleration maneuvers may apply the largest bending moments to the fifth metatarsal and could lead to stress fractures. Because fifth metatarsal stress fractures are associated with rapid increases in training volume, reducing the number of acceleration events may be effective in altering the balance between bone resorption and bone formation and reducing stress fracture risk. Careful planning of training programs allowing for adequate rest between intense bouts of exercise involving many acceleration maneuvers may be the best preventative measure.

  20. Oxygen Therapy

    MedlinePlus

    Oxygen therapy is a treatment that provides you with extra oxygen. Oxygen is a gas that your body needs to function. Normally, your lungs absorb ... in your home. A different kind of oxygen therapy is called hyperbaric oxygen therapy. It uses oxygen ...

  1. Plumbagin-induced apoptosis in lymphocytes is mediated through increased reactive oxygen species production, upregulation of Fas, and activation of the caspase cascade

    SciTech Connect

    McKallip, Robert J.; Lombard, Catherine; Sun Jingping; Ramakrishnan, Rupal

    2010-08-15

    Extracts from plants containing plumbagin (PLB) continue to be used as a treatment of a number of chronic immunologically-based diseases. However, most of these claims are supported only by anecdotal evidence with few scientific reports describing the mechanism of action or the efficacy of plumbagin in the suppression of the immune response. In the current study, we tested the hypothesis that plumbagin-induced suppression of the immune response was mediated through the induction of apoptosis. Splenocytes from C57BL/6 mice cultured in the presence of 0.5 {mu}M or greater concentrations of PLB significantly reduced proliferative responses to mitogens, including anti-CD3 mAbs, concanavalin A (Con A), lipopolysaccharide (LPS) and staphylococcal enterotoxin B (SEB) in vitro. Exposure of naive and activated splenocytes to PLB led to a significant increase in the levels of apoptosis. In addition, PLB treatment led to a significant increase in the levels of reactive oxygen species (ROS) in naive and activated splenocytes. Furthermore, treatment with the ROS scavenger, N-acetylcysteine (NAC), prevented PLB-induced apoptosis, suggesting a role of ROS in PLB-induced apoptosis. PLB-induced apoptosis led to ROS-mediated activation of both the extrinsic and intrinsic apoptotic pathways. In addition, plumbagin led to increased expression of Fas. Finally, treatment of mice with PLB (5 mg/kg) led to thymic and splenic atrophy as well as a significant suppression of the response to SEB and dinitroflourobenzene (DNFB) in vivo. Together, these results suggest that plumbagin has significant immunosuppressive properties which are mediated by generation of ROS, upregulation of Fas, and the induction of apoptosis.

  2. An Arabidopsis Zinc Finger Protein Increases Abiotic Stress Tolerance by Regulating Sodium and Potassium Homeostasis, Reactive Oxygen Species Scavenging and Osmotic Potential.

    PubMed

    Zang, Dandan; Li, Hongyan; Xu, Hongyun; Zhang, Wenhui; Zhang, Yiming; Shi, Xinxin; Wang, Yucheng

    2016-01-01

    Plant zinc finger proteins (ZFPs) comprise a large protein family and they are mainly involved in abiotic stress tolerance. Although Arabidopsis RING/FYVE/PHD ZFP At5g62460 (AtRZFP) is found to bind to zinc, whether it is involved in abiotic stress tolerance is still unknown. In the present study, we characterized the roles of AtRZFP in response to abiotic stresses. The expression of AtRZFP was induced significantly by salt and osmotic stress. AtRZFP positively mediates tolerance to salt and osmotic stress. Additionally, compared with wild-type Arabidopsis plants, plants overexpressing AtRZFP showed reduced reactive oxygen species (ROSs) accumulation, enhanced superoxide dismutase and peroxidase activity, increased soluble sugars and proline contents, reduced K(+) loss, decreased Na(+) accumulation, stomatal aperture and the water loss rate. Conversely, AtRZFP knockout plants displayed the opposite physiological changes when exposed to salt or osmotic stress conditions. These data suggested that AtRZFP enhances salt and osmotic tolerance through a series of physiological processes, including enhanced ROSs scavenging, maintaining Na(+) and K(+) homeostasis, controlling the stomatal aperture to reduce the water loss rate, and accumulating soluble sugars and proline to adjust the osmotic potential. PMID:27605931

  3. Antitumor effect of manumycin on colorectal cancer cells by increasing the reactive oxygen species production and blocking PI3K-AKT pathway

    PubMed Central

    Zhang, Jingyu; Jiang, Hua; Xie, Li; Hu, Jing; Li, Li; Yang, Mi; Cheng, Lei; Liu, Baorui; Qian, Xiaoping

    2016-01-01

    Manumycin is a natural, well-tolerated microbial metabolite and is regarded as a farnesyltransferase inhibitor. Some data suggest that manumycin inhibits proliferation of diverse cancer cells through various pathways. However, the antitumor effect of manumycin on colorectal cancer (CRC) remains unknown. In the present study, we investigated the antitumor effect of manumycin on CRC in vitro and in vivo. The results of cell viability assay revealed that the proliferation of the CRC cells was significantly inhibited by manumycin. Moreover, cell apoptosis induced by manumycin was also found in a time- and dose-dependent manner. Interestingly, treatment of the CRC cells with manumycin resulted in increased generation of reactive oxygen species. Subsequently, manumycin also decreased the phosphorylation of phosphatidylinositol 3-kinase (PI3K) and AKT, as well as the expression of caspase-9 and poly(ADP-ribose) polymerase (PARP) in a time-dependent manner. In addition, we found that N-acetyl-l-cysteine (NAC) attenuated the effect of manumycin on the PI3K-AKT pathway, and wortmannin reduced the effect of manumycin on caspase-9 and PARP expression. More importantly, the anticancer effect of manumycin was also observed in established tumor xenografts. Taken together, these findings supported the potential application of manumycin against colorectal carcinoma. PMID:27307747

  4. Increases in reactive oxygen species enhance vascular endothelial cell migration through a mechanism dependent on the transient receptor potential melastatin 4 ion channel.

    PubMed

    Sarmiento, Daniela; Montorfano, Ignacio; Cerda, Oscar; Cáceres, Mónica; Becerra, Alvaro; Cabello-Verrugio, Claudio; Elorza, Alvaro A; Riedel, Claudia; Tapia, Pablo; Velásquez, Luis A; Varela, Diego; Simon, Felipe

    2015-03-01

    A hallmark of severe inflammation is reactive oxygen species (ROS) overproduction induced by increased inflammatory mediators secretion. During systemic inflammation, inflammation mediators circulating in the bloodstream interact with endothelial cells (ECs) raising intracellular oxidative stress at the endothelial monolayer. Oxidative stress mediates several pathological functions, including an exacerbated EC migration. Because cell migration critically depends on calcium channel-mediated Ca(2+) influx, the molecular identification of the calcium channel involved in oxidative stress-modulated EC migration has been the subject of intense investigation. The transient receptor potential melastatin 4 (TRPM4) protein is a ROS-modulated non-selective cationic channel that performs several cell functions, including regulating intracellular Ca(2+) overload and Ca(2+) oscillation. This channel is expressed in multiple tissues, including ECs, and contributes to the migration of certain immune cells. However, whether the TRPM4 ion channel participates in oxidative stress-mediated EC migration is not known. Herein, we investigate whether oxidative stress initiates or enhances EC migration and study the role played by the ROS-modulated TRPM4 ion channel in oxidative stress-mediated EC migration. We demonstrate that oxidative stress enhances, but does not initiate, EC migration in a dose-dependent manner. Notably, we demonstrate that the TRPM4 ion channel is critical in promoting H2O2-enhanced EC migration. These results show that TRPM4 is a novel pharmacological target for the possible treatment of severe inflammation and other oxidative stress-mediated inflammatory diseases.

  5. Metformin Decreases Reactive Oxygen Species, Enhances Osteogenic Properties of Adipose-Derived Multipotent Mesenchymal Stem Cells In Vitro, and Increases Bone Density In Vivo.

    PubMed

    Marycz, Krzysztof; Tomaszewski, Krzysztof A; Kornicka, Katarzyna; Henry, Brandon Michael; Wroński, Sebastian; Tarasiuk, Jacek; Maredziak, Monika

    2016-01-01

    Due to its pleiotropic effects, the commonly used drug metformin has gained renewed interest among medical researchers. While metformin is mainly used for the treatment of diabetes, recent studies suggest that it may have further application in anticancer and antiaging therapies. In this study, we investigated the proliferative potential, accumulation of oxidative stress factors, and osteogenic and adipogenic differentiation potential of mouse adipose-derived stem cells (MuASCs) isolated from mice treated with metformin for 8 weeks. Moreover, we investigated the influence of metformin supplementation on mice bone density and bone element composition. The ASCs isolated from mice who were treated with metformin for 8 weeks showed highest proliferative potential, generated a robust net of cytoskeletal projections, had reduced expression of markers associated with cellular senescence, and decreased amount of reactive oxygen species in comparison to control group. Furthermore, we demonstrated that these cells possessed greatest osteogenic differentiation potential, while their adipogenic differentiation ability was reduced. We also demonstrated that metformin supplementation increases bone density in vivo. Our result stands as a valuable source of data regarding the in vivo influence of metformin on ASCs and bone density and supports a role for metformin in regenerative medicine. PMID:27195075

  6. Metformin Decreases Reactive Oxygen Species, Enhances Osteogenic Properties of Adipose-Derived Multipotent Mesenchymal Stem Cells In Vitro, and Increases Bone Density In Vivo

    PubMed Central

    Marycz, Krzysztof; Tomaszewski, Krzysztof A.; Kornicka, Katarzyna; Henry, Brandon Michael; Wroński, Sebastian; Tarasiuk, Jacek; Maredziak, Monika

    2016-01-01

    Due to its pleiotropic effects, the commonly used drug metformin has gained renewed interest among medical researchers. While metformin is mainly used for the treatment of diabetes, recent studies suggest that it may have further application in anticancer and antiaging therapies. In this study, we investigated the proliferative potential, accumulation of oxidative stress factors, and osteogenic and adipogenic differentiation potential of mouse adipose-derived stem cells (MuASCs) isolated from mice treated with metformin for 8 weeks. Moreover, we investigated the influence of metformin supplementation on mice bone density and bone element composition. The ASCs isolated from mice who were treated with metformin for 8 weeks showed highest proliferative potential, generated a robust net of cytoskeletal projections, had reduced expression of markers associated with cellular senescence, and decreased amount of reactive oxygen species in comparison to control group. Furthermore, we demonstrated that these cells possessed greatest osteogenic differentiation potential, while their adipogenic differentiation ability was reduced. We also demonstrated that metformin supplementation increases bone density in vivo. Our result stands as a valuable source of data regarding the in vivo influence of metformin on ASCs and bone density and supports a role for metformin in regenerative medicine. PMID:27195075

  7. Five-fold twinned Pd2NiAg nanocrystals with increased surface Ni site availability to improve oxygen reduction activity.

    PubMed

    Liu, Suli; Zhang, Qinghua; Li, Yafei; Han, Min; Gu, Lin; Nan, Cewen; Bao, Jianchun; Dai, Zhihui

    2015-03-01

    The synthesis of highly active oxygen reduction reaction (ORR) catalysts with good durability and low cost is highly desirable but still remains a significant challenge. In this work, we present the synthesis of five-fold twinned Pd2NiAg nanocrystals (NCs) with a Ni-terminal surface which exhibit excellent electrocatalytic performance for ORR in alkaline media, even better than the performance of the commercial Pt/C catalyst. Using high-angle annular-dark-field imaging together with density functional theory calculations, it is found that the surfaces of the five-fold twinned Pd2NiAg NCs exhibit an unusual valence electron density. The maximum catalytic activity originates from the increased availability of surface Ni sites in five-fold twinned Pd2NiAg NCs and the features of twinned structural defects. This study provides an explanation of the enhanced ORR from the special structure of this novel material, which opens up new avenues for the design of novel classes of electrocatalysts for fuel cells and metal-air batteries. PMID:25626352

  8. An Arabidopsis Zinc Finger Protein Increases Abiotic Stress Tolerance by Regulating Sodium and Potassium Homeostasis, Reactive Oxygen Species Scavenging and Osmotic Potential

    PubMed Central

    Zang, Dandan; Li, Hongyan; Xu, Hongyun; Zhang, Wenhui; Zhang, Yiming; Shi, Xinxin; Wang, Yucheng

    2016-01-01

    Plant zinc finger proteins (ZFPs) comprise a large protein family and they are mainly involved in abiotic stress tolerance. Although Arabidopsis RING/FYVE/PHD ZFP At5g62460 (AtRZFP) is found to bind to zinc, whether it is involved in abiotic stress tolerance is still unknown. In the present study, we characterized the roles of AtRZFP in response to abiotic stresses. The expression of AtRZFP was induced significantly by salt and osmotic stress. AtRZFP positively mediates tolerance to salt and osmotic stress. Additionally, compared with wild-type Arabidopsis plants, plants overexpressing AtRZFP showed reduced reactive oxygen species (ROSs) accumulation, enhanced superoxide dismutase and peroxidase activity, increased soluble sugars and proline contents, reduced K+ loss, decreased Na+ accumulation, stomatal aperture and the water loss rate. Conversely, AtRZFP knockout plants displayed the opposite physiological changes when exposed to salt or osmotic stress conditions. These data suggested that AtRZFP enhances salt and osmotic tolerance through a series of physiological processes, including enhanced ROSs scavenging, maintaining Na+ and K+ homeostasis, controlling the stomatal aperture to reduce the water loss rate, and accumulating soluble sugars and proline to adjust the osmotic potential. PMID:27605931

  9. An Arabidopsis Zinc Finger Protein Increases Abiotic Stress Tolerance by Regulating Sodium and Potassium Homeostasis, Reactive Oxygen Species Scavenging and Osmotic Potential

    PubMed Central

    Zang, Dandan; Li, Hongyan; Xu, Hongyun; Zhang, Wenhui; Zhang, Yiming; Shi, Xinxin; Wang, Yucheng

    2016-01-01

    Plant zinc finger proteins (ZFPs) comprise a large protein family and they are mainly involved in abiotic stress tolerance. Although Arabidopsis RING/FYVE/PHD ZFP At5g62460 (AtRZFP) is found to bind to zinc, whether it is involved in abiotic stress tolerance is still unknown. In the present study, we characterized the roles of AtRZFP in response to abiotic stresses. The expression of AtRZFP was induced significantly by salt and osmotic stress. AtRZFP positively mediates tolerance to salt and osmotic stress. Additionally, compared with wild-type Arabidopsis plants, plants overexpressing AtRZFP showed reduced reactive oxygen species (ROSs) accumulation, enhanced superoxide dismutase and peroxidase activity, increased soluble sugars and proline contents, reduced K+ loss, decreased Na+ accumulation, stomatal aperture and the water loss rate. Conversely, AtRZFP knockout plants displayed the opposite physiological changes when exposed to salt or osmotic stress conditions. These data suggested that AtRZFP enhances salt and osmotic tolerance through a series of physiological processes, including enhanced ROSs scavenging, maintaining Na+ and K+ homeostasis, controlling the stomatal aperture to reduce the water loss rate, and accumulating soluble sugars and proline to adjust the osmotic potential.

  10. Grafting of Cucumis sativus onto Cucurbita ficifolia leads to improved plant growth, increased light utilization and reduced accumulation of reactive oxygen species in chilled plants.

    PubMed

    Zhou, Yanhong; Zhou, Jie; Huang, Lifeng; Ding, Xiaotao; Shi, Kai; Yu, Jingquan

    2009-09-01

    The effects of chilling at 14 and 7 degrees C on plant growth, CO(2) assimilation, light allocation, photosynthetic electron flux and antioxidant metabolism were examined in cucumber (Cucumis sativus L. cv. Jinyan No. 4, CS) plants with figleaf gourd (Cucurbita ficifolia Bouché, CF) and cucumber as rootstocks, respectively. Growth inhibition by chilling at 7 degrees C was characterized by irreversible inhibition of CO(2) assimilation in grafted plants with cucumber as rootstock and scion (CS/CS) but this effect was significantly alleviated by grafting onto CF roots (CS/CF). Chilled CS/CF plants exhibited a higher photosynthetic activity and lower proportion of energy dissipation than chilled CS/CS plants. Chilling resulted in a greater decrease in the electron flux in photosystem (PS) II (J (PSII)) than the rate of energy dissipation either via light-dependent (J (NPQ)) or via constitutive thermal dissipation and fluorescence (J (f,D)) in CS/CS plants. In parallel with the reduction in J (PSII), electron flux to oxygenation (J (o)) and carboxylation by Rubisco (J (c)) all decreased significantly whilst alternative electron flux in PS II (J (a)) increased, especially in CS/CS plants. Moreover, CS/CF plants exhibited higher activity of antioxidant enzymes, lower antioxidant content and less membrane peroxidation relative to CS/CS plants after chilling.

  11. Increases in reactive oxygen species enhance vascular endothelial cell migration through a mechanism dependent on the transient receptor potential melastatin 4 ion channel.

    PubMed

    Sarmiento, Daniela; Montorfano, Ignacio; Cerda, Oscar; Cáceres, Mónica; Becerra, Alvaro; Cabello-Verrugio, Claudio; Elorza, Alvaro A; Riedel, Claudia; Tapia, Pablo; Velásquez, Luis A; Varela, Diego; Simon, Felipe

    2015-03-01

    A hallmark of severe inflammation is reactive oxygen species (ROS) overproduction induced by increased inflammatory mediators secretion. During systemic inflammation, inflammation mediators circulating in the bloodstream interact with endothelial cells (ECs) raising intracellular oxidative stress at the endothelial monolayer. Oxidative stress mediates several pathological functions, including an exacerbated EC migration. Because cell migration critically depends on calcium channel-mediated Ca(2+) influx, the molecular identification of the calcium channel involved in oxidative stress-modulated EC migration has been the subject of intense investigation. The transient receptor potential melastatin 4 (TRPM4) protein is a ROS-modulated non-selective cationic channel that performs several cell functions, including regulating intracellular Ca(2+) overload and Ca(2+) oscillation. This channel is expressed in multiple tissues, including ECs, and contributes to the migration of certain immune cells. However, whether the TRPM4 ion channel participates in oxidative stress-mediated EC migration is not known. Herein, we investigate whether oxidative stress initiates or enhances EC migration and study the role played by the ROS-modulated TRPM4 ion channel in oxidative stress-mediated EC migration. We demonstrate that oxidative stress enhances, but does not initiate, EC migration in a dose-dependent manner. Notably, we demonstrate that the TRPM4 ion channel is critical in promoting H2O2-enhanced EC migration. These results show that TRPM4 is a novel pharmacological target for the possible treatment of severe inflammation and other oxidative stress-mediated inflammatory diseases. PMID:24518820

  12. Increased levels of reactive oxygen species and expression of a cytoplasmic aconitase/iron regulatory protein 1 homolog during the early response of maize pulvini to gravistimulation.

    PubMed

    Clore, A M; Doore, S M; Tinnirello, S M N

    2008-01-01

    The maize (Zea mays L.) stem pulvinus is a disc of tissue located apical to each node that functions to return a tipped stem to a more upright position via increased cell elongation on its lower side. We investigated the possibility that reactive oxygen species (ROS) and hydrogen peroxide (H2O2), in particular, are involved in the gravitropic response of the pulvinus prior to initiation of the growth response by employing the cytochemical stain 3,3'-diaminobenzidine (DAB). DAB polymers were found in the bundle sheath cells of gravistimulated pulvini in association with amyloplasts after 1 min of gravistimulation, and the signal spread throughout the cytosol of these cells by 30 min. Furthermore, treatment of maize stem explants containing pulvini with 1 mm H2O2 on their upper sides caused reversal of bending polarity. Similar, though less dramatic, results were obtained via application of 1 mm ascorbic acid to the lower side of the explants. In addition, we determined that a maize cytoplasmic aconitase/iron regulatory protein 1 (IRP1) homolog is up-regulated in the pulvinus bundle sheath cells after gravistimulation using suppressive subtractive hybridization PCR (SSH PCR), real-time RT-PCR and in situ hybridization. Although we do not yet know the role of the IRP1 homolog in the pulvinus, the protein is known to be a redox sensor in other systems. Collectively, our results point to an increase in ROS quite early in the gravitropic signalling pathway and its possible role in determining the direction of bending of the pulvini. We speculate that an ROS burst may serve to link the physical phenomenon of amyloplast sedimentation to the changes in cellular biochemistry and gene expression that facilitate directional growth. PMID:18004982

  13. NG as a novel nitric oxide donor induces apoptosis by increasing reactive oxygen species and inhibiting mitochondrial function in MGC803 cells.

    PubMed

    Liu, Ling; Li, Tingting; Tan, Jiani; Fu, Junjie; Guo, Qianqian; Ji, Hui; Zhang, Yihua

    2014-11-01

    NG, O(2)-(2,4-dinitro-5-{[2-(12-en-28-β-D-galactopyranosyl-oleanolate-3-yl)-oxy-2-oxoethyl] amino} phenyl) 1-(N-hydroxyethylmethylamino) diazen-1-ium-1,2-diolate, was identified in our laboratory as a novel nitric oxide-releasing prodrug with antitumor effects. A previous study showed that NG inhibited cell growth, and induced apoptosis in HepG2 cells. In this study, the inhibitory effects of NG on the viability of MGC803 cells were examined using methylthiazolyl tetrazolium biomide (MTT) assay, neutral red assay and trypan blue exclusion test. The results showed that NG had strong cytotoxicity to induce apoptosis, which was characterized by a significant externalization of phosphatidylserine, nuclear morphological changes and enhanced Bax-to-Bcl-2 ratio. Moreover, the release of cytochrome c (Cyt c) from mitochondria and the activation of caspase-9/3 were also detected, indicating that NG may induce apoptosis through a mitochondrial-mediated pathway. NG induced mitochondrial dysfunction in MGC803 cells by altering membrane potential (△Ψm), the inhibition of complexes I, II and IV consequently decreasing ATP level. Furthermore, the treatment of MGC803 cells with NG caused a marked rise in oxidative stress as characterized by accumulation of reactive oxygen species (ROS), excessive malondialdehyde (MDA) production and a reduction in glutathione hormone (GSH) level and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity. In addition, pretreatment with N-acetylcysteine (NAC), a GSH synthesis precursor, was partially protective against the NG-induced ROS generation and cell apoptosis. In contrast, pretreatment of MGC803 cells with L-buthionine-S, R-sulfoximine (BSO), a GSH synthesis inhibitor, increased the ROS levels, and aggravated cell apoptosis by NG. These results suggest that NG-induced apoptosis in MGC803 cells is mediated, at least in part, by the increase in ROS production, oxidative stress and mitochondrial dysfunction. PMID:25135879

  14. Oxygen-glucose deprivation increases the enzymatic activity and the microvesicle-mediated release of ectonucleotidases in the cells composing the blood-brain barrier.

    PubMed

    Ceruti, Stefania; Colombo, Laura; Magni, Giulia; Viganò, Francesca; Boccazzi, Marta; Deli, Mária A; Sperlágh, Beáta; Abbracchio, Maria P; Kittel, Agnes

    2011-08-01

    The blood-brain barrier (BBB), the dynamic interface between the nervous tissue and the blood, is composed by endothelial cells, pericytes and astrocytes. Extracellular nucleotides and nucleosides and their receptors (the purinergic system) constitute a widely diffused signaling system involved in many pathophysiological processes. However, the role of this system in controlling BBB functions is still largely unknown. By using cultures of these three cell types grown separately and a BBB in vitro model consisting of triple co-cultures, we studied for the first time the expression and distribution of the ecto-enzymes nucleoside triphosphate diphosphohydrolases (NTPDases, the enzymes which hydrolyze extracellular nucleotides) under control and ischemic (oxygen-glucose deprivation in vitro; OGD) conditions. NTPDase1 was detected in all three cell types, whereas NTPDase2 was expressed by astrocytes and pericytes and, to a lesser extent, by endothelial cells. Endothelial cells were extremely susceptible to cell death when OGD was applied to mimic in vitro the cytotoxicity induced by ischemia, whereas astrocytes and pericytes were more resistant. A semi-quantitative assay highlighted markedly increased e-ATPase activity following exposure to OGD in all three cell types, either when grown separately or when co-cultured together to resemble the composition of the BBB. Moreover, electron microscopy analysis showed that both endothelial cells and astrocytes shed microvesicles containing NTPDases from their membrane, which may suggest a novel mechanism to increase the breakdown of ATP released to toxic levels by damaged BBB cells. We hypothesize that this phenomenon could have a protective and/or modulatory effect for brain parenchymal cells. This in vitro model is therefore useful to study the role of extracellular nucleotides in modulating BBB responses to ischemic events, and to develop new effective purinergic-based approaches for brain ischemia.

  15. Ultra-fast escape maneuver of an octopus-inspired robot.

    PubMed

    Weymouth, G D; Subramaniam, V; Triantafyllou, M S

    2015-01-01

    We design and test an octopus-inspired flexible hull robot that demonstrates outstanding fast-starting performance. The robot is hyper-inflated with water, and then rapidly deflates to expel the fluid so as to power the escape maneuver. Using this robot we verify for the first time in laboratory testing that rapid size-change can substantially reduce separation in bluff bodies traveling several body lengths, and recover fluid energy which can be employed to improve the propulsive performance. The robot is found to experience speeds over ten body lengths per second, exceeding that of a similarly propelled optimally streamlined rigid rocket. The peak net thrust force on the robot is more than 2.6 times that on an optimal rigid body performing the same maneuver, experimentally demonstrating large energy recovery and enabling acceleration greater than 14 body lengths per second squared. Finally, over 53% of the available energy is converted into payload kinetic energy, a performance that exceeds the estimated energy conversion efficiency of fast-starting fish. The Reynolds number based on final speed and robot length is [Formula: see text]. We use the experimental data to establish a fundamental deflation scaling parameter [Formula: see text] which characterizes the mechanisms of flow control via shape change. Based on this scaling parameter, we find that the fast-starting performance improves with increasing size. PMID:25643048

  16. Ultra-fast escape maneuver of an octopus-inspired robot.

    PubMed

    Weymouth, G D; Subramaniam, V; Triantafyllou, M S

    2015-02-02

    We design and test an octopus-inspired flexible hull robot that demonstrates outstanding fast-starting performance. The robot is hyper-inflated with water, and then rapidly deflates to expel the fluid so as to power the escape maneuver. Using this robot we verify for the first time in laboratory testing that rapid size-change can substantially reduce separation in bluff bodies traveling several body lengths, and recover fluid energy which can be employed to improve the propulsive performance. The robot is found to experience speeds over ten body lengths per second, exceeding that of a similarly propelled optimally streamlined rigid rocket. The peak net thrust force on the robot is more than 2.6 times that on an optimal rigid body performing the same maneuver, experimentally demonstrating large energy recovery and enabling acceleration greater than 14 body lengths per second squared. Finally, over 53% of the available energy is converted into payload kinetic energy, a performance that exceeds the estimated energy conversion efficiency of fast-starting fish. The Reynolds number based on final speed and robot length is [Formula: see text]. We use the experimental data to establish a fundamental deflation scaling parameter [Formula: see text] which characterizes the mechanisms of flow control via shape change. Based on this scaling parameter, we find that the fast-starting performance improves with increasing size.

  17. Numerical Investigation of Bending-Body Projectile Aerodynamics for Maneuver Control

    NASA Astrophysics Data System (ADS)

    Youn, Eric; Silton, Sidra

    2015-11-01

    Precision munitions are an active area of research for the U.S. Army. Canard-control actuators have historically been the primary mechanism used to maneuver fin-stabilized, gun-launched munitions. Canards are small, fin-like control surfaces mounted at the forward section of the munition to provide the pitching moment necessary to rotate the body in the freestream flow. The additional lift force due to the rotated body and the canards then alters the flight path toward the intended target. As velocity and maneuverability requirements continue to increase, investigation of other maneuver mechanisms becomes necessary. One option for a projectile with a large length-to-diameter ratio (L/D) is a bending-body design, which imparts a curvature to the projectile body along its axis. This investigation uses full Navier-Stokes computational fluid dynamics simulations to evaluate the effectiveness of an 8-degree bent nose tip on an 8-degree bent forward section of an L/D =10 projectile. The aerodynamic control effectiveness of the bending-body concept is compared to that of a standard L/D =10 straight-body projectile as well as that of the same projectile with traditional canards. All simulations were performed at supersonic velocities between Mach 2-4.

  18. An adaptive guidance algorithm for an aerodynamically assisted orbital plane change maneuver. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Blissit, J. A.

    1986-01-01

    Using analysis results from the post trajectory optimization program, an adaptive guidance algorithm is developed to compensate for density, aerodynamic and thrust perturbations during an atmospheric orbital plane change maneuver. The maneuver offers increased mission flexibility along with potential fuel savings for future reentry vehicles. Although designed to guide a proposed NASA Entry Research Vehicle, the algorithm is sufficiently generic for a range of future entry vehicles. The plane change analysis provides insight suggesting a straight-forward algorithm based on an optimized nominal command profile. Bank angle, angle of attack, and engine thrust level, ignition and cutoff times are modulated to adjust the vehicle's trajectory to achieve the desired end-conditions. A performance evaluation of the scheme demonstrates a capability to guide to within 0.05 degrees of the desired plane change and five nautical miles of the desired apogee altitude while maintaining heating constraints. The algorithm is tested under off-nominal conditions of + or -30% density biases, two density profile models, + or -15% aerodynamic uncertainty, and a 33% thrust loss and for various combinations of these conditions.

  19. Orbit Maneuver Compensation of KAGUYA for Its Safe and Accurate Lunar Transfer

    NASA Astrophysics Data System (ADS)

    Kawakatsu, Yasuhiro; Terada, Hiroshi; Matsuoka, Masatoshi; Ohnishi, Takafumi

    Reported in this paper are the results of the orbit maneuver compensation in KAGUYA's Lunar transfer. Because of the uncoupled allocation of the attitude control thrusters, extra velocity increment (δv ) is induced whenever KAGUYA performs an orbit maneuver. Since the observed level of δv was unacceptable range from the point of maneuver accuracy requirement, it was compensated by means of deducting estimated δv from the orbit maneuver command. The δv estimation model was updated step-by-step during the Lunar transfer, which leaded to significant improvement of the orbit maneuver accuracy and resulted in the omission of the last trajectory correction maneuver. The method of the compensation and its results are introduced in detail.

  20. Cassini Orbit Trim Maneuvers at Saturn - Overview of Attitude Control Flight Operations

    NASA Technical Reports Server (NTRS)

    Burk, Thomas A.

    2011-01-01

    The Cassini spacecraft has been in orbit around Saturn since July 1, 2004. To remain on the planned trajectory which maximizes science data return, Cassini must perform orbit trim maneuvers using either its main engine or its reaction control system thrusters. Over 200 maneuvers have been executed on the spacecraft since arrival at Saturn. To improve performance and maintain spacecraft health, changes have been made in maneuver design command placement, in accelerometer scale factor, and in the pre-aim vector used to align the engine gimbal actuator prior to main engine burn ignition. These and other changes have improved maneuver performance execution errors significantly since 2004. A strategy has been developed to decide whether a main engine maneuver should be performed, or whether the maneuver can be executed using the reaction control system.

  1. A Semi-Empirical Noise Modeling Method for Helicopter Maneuvering Flight Operations

    NASA Technical Reports Server (NTRS)

    Greenwood, Eric; Schmitz, Fredric; Sickenberger, Richard D.

    2012-01-01

    A new model for Blade-Vortex Interaction noise generation during maneuvering flight is developed in this paper. Acoustic and performance data from both flight and wind tunnels are used to derive a non-dimensional and analytical performance/acoustic model that describes BVI noise in steady flight. The model is extended to transient maneuvering flight (pure pitch and roll transients) by using quasisteady assumptions throughout the prescribed maneuvers. Ground noise measurements, taken during maneuvering flight of a Bell 206B helicopter, show that many of the noise radiation details are captured. The result is a computationally efficient Blade-Vortex Interaction noise model with sufficient accuracy to account for transient maneuvering flight. The code can be run in real time to predict transient maneuver noise and is suitable for use in an acoustic mission-planning tool.

  2. Maneuvering Rotorcraft Noise Prediction: A New Code for a New Problem

    NASA Technical Reports Server (NTRS)

    Brentner, Kenneth S.; Bres, Guillaume A.; Perez, Guillaume; Jones, Henry E.

    2002-01-01

    This paper presents the unique aspects of the development of an entirely new maneuver noise prediction code called PSU-WOPWOP. The main focus of the code is the aeroacoustic aspects of the maneuver noise problem, when the aeromechanical input data are provided (namely aircraft and blade motion, blade airloads). The PSU-WOPWOP noise prediction capability was developed for rotors in steady and transient maneuvering flight. Featuring an object-oriented design, the code allows great flexibility for complex rotor configuration and motion (including multiple rotors and full aircraft motion). The relative locations and number of hinges, flexures, and body motions can be arbitrarily specified to match the any specific rotorcraft. An analysis of algorithm efficiency is performed for maneuver noise prediction along with a description of the tradeoffs made specifically for the maneuvering noise problem. Noise predictions for the main rotor of a rotorcraft in steady descent, transient (arrested) descent, hover and a mild "pop-up" maneuver are demonstrated.

  3. Increased transcutaneous oxygen tension in the skin dorsum over the foot in patients with diabetic foot disease in response to the topical use of an emulsion of hyperoxygenated Fatty acids.

    PubMed

    Lázaro-Martínez, J L; Sánchez-Ríos, J P; García-Morales, E; Cecilia-Matilla, A; Segovia-Gómez, T

    2009-12-01

    The aim of this study was to examine changes in the skin over the feet of patients with diabetic foot syndrome after local application of a product containing hyperoxygenated fatty acids (HOFAs) by measuring transcutaneous oxygen. In 64 patients, transcutaneous oxygen pressure (TcPo(2)) was measured on days 0, 7, 30, 60, and 90 of the study. Foot skin dryness, shedding, and skin color were also assessed using a clinical score. The patients were grouped on the basis of initial levels of transcutaneous oxygen; group 1 comprised patients with TcPo( 2) >30 mm Hg and group 2 comprised patients with TcPo(2) <30 mm Hg on the skin over the dorsum of the feet. Increases in local oxygenation values were observed at a local level in group 2 patients after 30 days of treatment. Skin trophism showed clinical improvement in all patients and these observations may be attributed to improved local microcirculation.

  4. Hepatic ischemia-reperfusion syndrome after partial liver resection (LR): hepatic venous oxygen saturation, enzyme pattern, reduced and oxidized glutathione, procalcitonin and interleukin-6.

    PubMed

    Kretzschmar, Michael; Krüger, Antie; Schirrmeister, Wulf

    2003-06-01

    The hepatic ischemia-reperfusion syndrome was investigated in 28 patients undergoing elective partial liver resection with intraoperative occlusion of hepatic inflow (Pringle maneuver) using the technique of liver vein catheterization. Hepatic venous oxygen saturation (ShvO2) was monitored continuously up to 24 hours after surgery. Aspartate aminotransferase, glutamate dehydrogenase, gamma-glutamyl transpeptidase, pseudocholinesterase, alpha-glutathione S-transferase, reduced and oxidized glutathione, procalcitonine, and interleukin-6 were serially measured both before and after Pringle maneuver during the resection and postoperatively in arterial and/or hepatic venous blood. ShvO2 measurement demonstrated that peri- and postoperative management was suitable to maintain an optimal hepatic oxygen supply. As expected, we were able to demonstrate a typical enzyme pattern of postischemic liver injury. There was a distinct decrease of reduced glutathione levels both in arterial and hepatic venous plasma after LR accompanied by a strong increase in oxidized glutathione concentration during the phase of reperfusion. We observed increases in procalcitonin and interleukin-6 levels both in arterial and hepatic venous blood after declamping. Our data support the view that liver resection in man under conditions of inflow occlusion resulted in ischemic lesion of the liver (loss of glutathione synthesizing capacity with disturbance of protection against oxidative stress) and an additional impairment during reperfusion (liberation of reactive oxygen species, local and systemic inflammation reaction with cytokine production). Additionally, we found some evidence for the assumption that the liver has an export function for reduced glutathione into plasma in man. PMID:12877355

  5. Computing and Visualizing Reachable Volumes for Maneuvering Satellites

    SciTech Connect

    Jiang, M; de Vries, W H; Pertica, A J; Olivier, S S

    2011-09-11

    Detecting and predicting maneuvering satellites is an important problem for Space Situational Awareness. The spatial envelope of all possible locations within reach of such a maneuvering satellite is known as the Reachable Volume (RV). As soon as custody of a satellite is lost, calculating the RV and its subsequent time evolution is a critical component in the rapid recovery of the satellite. In this paper, we present a Monte Carlo approach to computing the RV for a given object. Essentially, our approach samples all possible trajectories by randomizing thrust-vectors, thrust magnitudes and time of burn. At any given instance, the distribution of the 'point-cloud' of the virtual particles defines the RV. For short orbital time-scales, the temporal evolution of the point-cloud can result in complex, multi-reentrant manifolds. Visualization plays an important role in gaining insight and understanding into this complex and evolving manifold. In the second part of this paper, we focus on how to effectively visualize the large number of virtual trajectories and the computed RV. We present a real-time out-of-core rendering technique for visualizing the large number of virtual trajectories. We also examine different techniques for visualizing the computed volume of probability density distribution, including volume slicing, convex hull and isosurfacing. We compare and contrast these techniques in terms of computational cost and visualization effectiveness, and describe the main implementation issues encountered during our development process. Finally, we will present some of the results from our end-to-end system for computing and visualizing RVs using examples of maneuvering satellites.

  6. Command shaping for residual vibration free crane maneuvers

    SciTech Connect

    Parker, G.G.; Petterson, B.; Dohrmann, C.; Robinett, R.D.

    1995-07-01

    Cranes used in the construction and transportation industries are generally devices with multiple degrees of freedom including variable load-line length, variable jib length (usually via a trolley), and variable boom angles. Point-to-point payload maneuvers using cranes are performed so as not to excite the spherical pendulum modes of their cable and payload assemblies. Typically, these pendulum modes, although time-varying, exhibit low frequencies. Current crane maneuvers are therefore performed slowly contributing to high construction and transportation costs. This investigation details a general method for applying command shaping to various multiple degree of freedom cranes such that the payload moves to a specified point without residual oscillation. A dynamic programming method is used for general command shaping for optimal maneuvers. Computationally, the dynamic programming approach requires order M calculations to arrive at a solution, where M is the number of discretizations of the input commands. This feature is exploited for the crane command shaping problem allowing for rapid calculation of command histories. Fast generation of commands is a necessity for practical use of command shaping for the applications described in this work. These results are compared to near-optimal solutions where the commands are linear combinations of acceleration pulse basis functions. The pulse shape is required due to hardware requirements. The weights on the basis functions are chosen as the solution to a parameter optimization problem solved using a Recursive Quadratic Programming technique. Simulation results and experimental verification for a variable load-line length rotary crane are presented using both design procedures.

  7. Development of a Smooth Trajectory Maneuver Method to Accommodate the Ares I Flight Control Constraints

    NASA Technical Reports Server (NTRS)

    Pinson, Robin M.; Schmitt, Terri L.; Hanson, John M.

    2008-01-01

    Six degree-of-freedom (DOF) launch vehicle trajectories are designed to follow an optimized 3-DOF reference trajectory. A vehicle has a finite amount of control power that it can allocate to performing maneuvers. Therefore, the 3-DOF trajectory must be designed to refrain from using 100% of the allowable control capability to perform maneuvers, saving control power for handling off-nominal conditions, wind gusts and other perturbations. During the Ares I trajectory analysis, two maneuvers were found to be hard for the control system to implement; a roll maneuver prior to the gravity turn and an angle of attack maneuver immediately after the J-2X engine start-up. It was decided to develop an approach for creating smooth maneuvers in the optimized reference trajectories that accounts for the thrust available from the engines. A feature of this method is that no additional angular velocity in the direction of the maneuver has been added to the vehicle after the maneuver completion. This paper discusses the equations behind these new maneuvers and their implementation into the Ares I trajectory design cycle. Also discussed is a possible extension to adjusting closed-loop guidance.

  8. Development of control laws for a flight test maneuver autopilot for an F-15 aircraft

    NASA Technical Reports Server (NTRS)

    Alag, G. S.; Duke, E. L.

    1985-01-01

    An autopilot can be used to provide precise control to meet the demanding requirements of flight research maneuvers with high-performance aircraft. The development of control laws within the context of flight test maneuver requirements is discussed. The control laws are developed using eigensystem assignment and command generator tracking. The eigenvalues and eigenvectors are chosen to provide the necessary handling qualities, while the command generator tracking enables the tracking of a specified state during the maneuver. The effectiveness of the control laws is illustrated by their application to an F-15 aircraft to ensure acceptable aircraft performance during a maneuver.

  9. Analysis of Transfer Maneuvers from Initial Circular Orbit to a Final Circular or Elliptic Orbit

    NASA Astrophysics Data System (ADS)

    Sharaf, M. A.; Saad, A. S.

    2016-04-01

    In the present paper an analysis of the transfer maneuvers from initial circular orbit to a final circular or elliptic orbit was developed to study the problem of impulsive transfers for space missions. It considers planar maneuvers using newly derived equations. With these equations, comparisons of circular and elliptic maneuvers are made. This comparison is important for the mission designers to obtain useful mappings showing where one maneuver is better than the other. In this aspect, we developed this comparison throughout ten results, together with some graphs to show their meaning.

  10. Space Shuttle OMS engine valve technology. [Orbital Maneuvering System

    NASA Technical Reports Server (NTRS)

    Wichmann, H.

    1974-01-01

    Valve technology program to determine shutoff valve concepts suitable for the Orbital Maneuvering System (OMS) engine of the Space Shuttle. The tradeoff studies selected the electric torque motor operated dual poppet and ball valves as the most desirable valve concepts for the OMS Engine Shutoff Valve. A prototype of one of these concepts was built and subjected to a design verification program. A number of unique features were designed to include the required contamination insensitivity, operating fluid compatibility, decontamination capability, minimum maintenance requirement and long service life capability.

  11. Sequential Probability Ratio Test for Collision Avoidance Maneuver Decisions

    NASA Technical Reports Server (NTRS)

    Carpenter, J. Russell; Markley, F. Landis

    2010-01-01

    When facing a conjunction between space objects, decision makers must chose whether to maneuver for collision avoidance or not. We apply a well-known decision procedure, the sequential probability ratio test, to this problem. We propose two approaches to the problem solution, one based on a frequentist method, and the other on a Bayesian method. The frequentist method does not require any prior knowledge concerning the conjunction, while the Bayesian method assumes knowledge of prior probability densities. Our results show that both methods achieve desired missed detection rates, but the frequentist method's false alarm performance is inferior to the Bayesian method's

  12. The aerodynamics of free-flight maneuvers in Drosophila.

    PubMed

    Fry, Steven N; Sayaman, Rosalyn; Dickinson, Michael H

    2003-04-18

    Using three-dimensional infrared high-speed video, we captured the wing and body kinematics of free-flying fruit flies as they performed rapid flight maneuvers. We then "replayed" the wing kinematics on a dynamically scaled robotic model to measure the aerodynamic forces produced by the wings. The results show that a fly generates rapid turns with surprisingly subtle modifications in wing motion, which nonetheless generate sufficient torque for the fly to rotate its body through each turn. The magnitude and time course of the torque and body motion during rapid turns indicate that inertia, not friction, dominates the flight dynamics of insects.

  13. Pseudosteady-state analysis of nonlinear aircraft maneuvers

    NASA Technical Reports Server (NTRS)

    Young, J. W.; Schy, A. A.; Johnson, K. G.

    1980-01-01

    An analytical method was developed for studying the combined effects of rotational coupling and nonlinear aerodynamics on aircraft response for specified control inputs. The method involves the simultaneous solution of two nonlinear equations which are functions of angle attack, roll rate, and control inputs. The method was applied to a number of maneuvers for a fighter-type aircraft. Time history responses verified the usefulness of the analysis for predicting a variety of response characteristics caused by interacting nonlinear aerodynamic and inertial effects, including spin conditions.

  14. Near Earth Asteroid redirect missions based on gravity assist maneuver

    NASA Astrophysics Data System (ADS)

    Ledkov, Anton; Shustov, Boris M.; Eismont, Natan; Boyarsky, Michael; Nazirov, Ravil; Fedyaev, Konstantin

    During last years several events attracted world community attention to the hazards of hitting the Earth by sky objects. One of these objects is Apophis asteroid what was expected with nonzero probability to hit the Earth in 2036. Luckily after more precise measurements this event is considered as practically improbable. But the other object has really reached the Earth, entered the atmosphere in the Chelyabinsk area and caused vast damages. After this the hazardous near Earth objects problem received practical confirmation of the necessity to find the methods of its resolution. The methods to prevent collision of the dangerous sky object with the Earth proposed up to now look not practical enough if one mentions such as gravitational tractor or changing the reflectivity of the asteroid surface. Even the method supposing the targeting of the spacecraft to the hazardous object in order to deflect it from initial trajectory by impact does not work because its low mass as compared with the mass of asteroid to be deflected. For example the mass of the Apophis is estimated to be about 40 million tons but the spacecraft which can be launched to intercept the asteroid using contemporary launchers has the mass not more than 5 tons. So the question arises where to find the heavier projectile which is possible to direct to the dangerous object? The answer proposed in our paper is very simple: to search it among small near Earth asteroids. As small ones we suppose those which have the cross section size not more than 12-15 meters and mass not exceeding 1500 -1700 tons. According to contemporary estimates the number of such asteroids is not less than 100000. The other question is how to redirect such asteroid to the dangerous one. In the paper the possibilities are studied to use for that purpose gravity assist maneuvers near Earth. It is shown that even among asteroids included in contemporary catalogue there are the ones which could be directed to the trajectory of the

  15. The Orbital Maneuvering Vehicle Training Facility visual system concept

    NASA Technical Reports Server (NTRS)

    Williams, Keith

    1989-01-01

    The purpose of the Orbital Maneuvering Vehicle (OMV) Training Facility (OTF) is to provide effective training for OMV pilots. A critical part of the training environment is the Visual System, which will simulate the video scenes produced by the OMV Closed-Circuit Television (CCTV) system. The simulation will include camera models, dynamic target models, moving appendages, and scene degradation due to the compression/decompression of video signal. Video system malfunctions will also be provided to ensure that the pilot is ready to meet all challenges the real-world might provide. One possible visual system configuration for the training facility that will meet existing requirements is described.

  16. Error Analysis and Trajectory Correction Maneuvers of Lunar Transfer Orbit

    NASA Astrophysics Data System (ADS)

    Zhao, Yu-hui; Hou, Xi-yun; Liu, Lin

    2013-10-01

    For a returnable lunar probe, this paper studies the characteristics of both the Earth-Moon transfer orbit and the return orbit. On the basis of the error propagation matrix, the linear equation to estimate the first midcourse trajectory correction maneuver (TCM) is figured out. Numerical simulations are performed, and the features of error propagation in lunar transfer orbit are given. The advantages, disadvantages, and applications of two TCM strategies are discussed, and the computation of the second TCM of the return orbit is also simulated under the conditions at the reentry time.

  17. Error Analysis and Trajectory Correction Maneuvers of Lunar Transfer Orbit

    NASA Astrophysics Data System (ADS)

    Zhao, Y. H.; Hou, X. Y.; Liu, L.

    2013-05-01

    For the sample return lunar missions and human lunar exploration, this paper studies the characteristics of both the Earth-Moon transfer orbit and the return orbit. On the basis of the error propagation matrix, the linear equation to estimate the first midcourse trajectory correction maneuver (TCM) is figured out. Numerical simulations are performed, and the features of error propagation in lunar transfer orbit are given. The advantages, disadvantages, and applications of two TCM strategies are discussed, and the computation of the second TCM of the return orbit is also simulated under the conditions at the reentry time.

  18. Flight simulator fidelity assessment in a rotorcraft lateral translation maneuver

    NASA Technical Reports Server (NTRS)

    Hess, R. A.; Malsbury, T.; Atencio, A., Jr.

    1992-01-01

    A model-based methodology for assessing flight simulator fidelity in closed-loop fashion is exercised in analyzing a rotorcraft low-altitude maneuver for which flight test and simulation results were available. The addition of a handling qualities sensitivity function to a previously developed model-based assessment criteria allows an analytical comparison of both performance and handling qualities between simulation and flight test. Model predictions regarding the existence of simulator fidelity problems are corroborated by experiment. The modeling approach is used to assess analytically the effects of modifying simulator characteristics on simulator fidelity.

  19. Safe Maneuvering Envelope Estimation Based on a Physical Approach

    NASA Technical Reports Server (NTRS)

    Lombaerts, Thomas J. J.; Schuet, Stefan R.; Wheeler, Kevin R.; Acosta, Diana; Kaneshige, John T.

    2013-01-01

    This paper discusses a computationally efficient algorithm for estimating the safe maneuvering envelope of damaged aircraft. The algorithm performs a robust reachability analysis through an optimal control formulation while making use of time scale separation and taking into account uncertainties in the aerodynamic derivatives. This approach differs from others since it is physically inspired. This more transparent approach allows interpreting data in each step, and it is assumed that these physical models based upon flight dynamics theory will therefore facilitate certification for future real life applications.

  20. OMV: A simplified mathematical model of the orbital maneuvering vehicle

    NASA Technical Reports Server (NTRS)

    Teoh, W.

    1984-01-01

    A model of the orbital maneuvering vehicle (OMV) is presented which contains several simplications. A set of hand controller signals may be used to control the motion of the OMV. Model verification is carried out using a sequence of tests. The dynamic variables generated by the model are compared, whenever possible, with the corresponding analytical variables. The results of the tests show conclusively that the present model is behaving correctly. Further, this model interfaces properly with the state vector transformation module (SVX) developed previously. Correct command sentence sequences are generated by the OMV and and SVX system, and these command sequences can be used to drive the flat floor simulation system at MSFC.