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  • Aeronautics (General)  (16)
  • Aerospace Medicine  (9)
  • 2015-2019  (19)
  • 2000-2004  (5)
  • 1955-1959  (1)
  • 1
    Publication Date: 2011-08-24
    Description: Prolonged exposure of humans and experimental animals to the altered gravitational conditions of space flight has adverse effects on the lymphoid and erythroid hematopoietic systems. Although some information is available regarding the cellular and molecular changes in lymphocytes exposed to microgravity, little is known about the erythroid cellular changes that may underlie the reduction in erythropoiesis and resultant anemia. We now report a reduction in erythroid growth and a profound inhibition of erythropoietin (Epo)-induced differentiation in a ground-based simulated microgravity model system. Rauscher murine erythroleukemia cells were grown either in tissue culture vessels at 1 x g or in the simulated microgravity environment of the NASA-designed rotating wall vessel (RWV) bioreactor. Logarithmic growth was observed under both conditions; however, the doubling time in simulated microgravity was only one-half of that seen at 1 x g. No difference in apoptosis was detected. Induction with Epo at the initiation of the culture resulted in differentiation of approximately 25% of the cells at 1 x g, consistent with our previous observations. In contrast, induction with Epo at the initiation of simulated microgravity resulted in only one-half of this degree of differentiation. Significantly, the growth of cells in simulated microgravity for 24 h prior to Epo induction inhibited the differentiation almost completely. The results suggest that the NASA RWV bioreactor may serve as a suitable ground-based microgravity simulator to model the cellular and molecular changes in erythroid cells observed in true microgravity.
    Keywords: Aerospace Medicine
    Type: In vitro cellular & developmental biology. Animal (ISSN 1071-2690); Volume 37; 2; 79-83
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  • 2
    Publication Date: 2018-03-10
    Description: No abstract available
    Keywords: Aeronautics (General)
    Type: AFRC-E-DAA-TN53598 , 2018 FAA UAS Symposium; 6-8 Mar. 2018; Baltimore, MD; United States
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  • 3
    Publication Date: 2019-06-27
    Description: The effect of missile armament on the performance of an interceptor-type aircraft model has been determined at Mach numbers 1.5, 1.7, and 1.9 and at angles of attack to 19 deg. With this configuration missiles were carried in a bay located on the bottom of the aircraft fuselage and mounted to a rotatable missile door. Rotation of the door then brought the missiles into the external or firing position. The aircraft model was characterized by triangular-shaped normal-shock inlets located at the wing roots. Relatively short and curved subsonic diffusers fed simulated twin side-by-side turbojet engines. Inasmuch as the missile bay extended considerably ahead of the inlet station, rotation of the missile door created considerable disturbance of the flow entering the inlets. In comparison with the internal missile arrangement, the external missile configurations increased the model lift, drag, and pitching moment. While the diffuser-exit flow distortion and static-pressure fluctuations were not greatly affected, diffuser total-pressure recovery was reduced as much as 0.058 at Mach number 1.9 for one missile configuration. The most detrimental effect of missile-door rotation occurred at the transient door positions, or with the door halfwzy between the missiles-in and -out conditions. At this door position the flow into the inlets was highly asymmetrical. Although the performance of both left and right ducts was generally reduced, the inlet duct on the cavity side of the missile door was most severely penalized, becoming unstable recovery losses and increases in flow distortion. The installation of fuselage fences along the missile bay was only partially effective in reducing these losses.
    Keywords: Aeronautics (General)
    Type: NACA-RM-E57A11a
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  • 4
    Publication Date: 2019-07-17
    Description: Bone and calcium homeostasis are altered by weightlessness. We previously reported calcium studies on three subjects from the first joint US/Russian mission to Mir. We report here data on an additional three male subjects, whose stays on Mir were 4 (n= 1) and 6 (n=2) mos. Data were collected before, during, and after the missions. Inflight studies were conducted at 2-3 mos. Endocrine and biochemical indices were measured, along with 3-wk calcium tracer studies. Percent differences are reported compared to preflight. Ionized calcium was unchanged (2.8 +/-2.1 %) during flight. Calcium absorption was variable inflight, but was decreased after landing. Vitamin D stores were decreased 35 +/-24% inflight, similar to previous reports. Serum PTH was decreased 59 +/-9% during flight (greater than we previously reported), while 1,25(OH)(sub 2)-Vitamin D was decreased in 2 of 3 subjects. Markers of bone resorption (e.g., crosslinks) were increased in all subjects. Bone-specific alkaline phosphatase was decreased (n=1) or unchanged (n=2), while osteocalcin was decreased 34 +/-23%. Previously presented data showed that inflight bone loss is associated with increased resorption and unchanged/decreased formation. The data reported here support these earlier findings. These studies will help to extend our understanding of space flight-induced bone loss, and of bone loss associated with diseases such as osteoporosis or paralysis.
    Keywords: Aerospace Medicine
    Type: Experimental Biology; Apr 15, 2000 - Apr 18, 2000; San Diego, CA; United States
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  • 5
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    In:  CASI
    Publication Date: 2019-07-13
    Description: This presentation includes the UAS-Enabled Market Categories used in Study, as well as the reason for the UAS-NAS NO Chase COA flight. It discusses the transitioning of a UA from different airspaces. UAS Integration is a community wide effort, and the FAA Symposium provides attendees with the opportunity to engage face-to-face with a cross-section of government and industry leaders and innovators about the latest industry developments, regulations, research, and other initiatives to safely integrate UAS into the National Airspace System (NAS).
    Keywords: Aeronautics (General)
    Type: AFRC-E-DAA-TN53416 , 2018 FAA UAS Symposium; Mar 06, 2018 - Mar 08, 2018; Baltimore, MD; United States
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  • 6
    Publication Date: 2019-08-14
    Description: This presentation gives insight into the research activities and efforts being executed in order to integrate unmanned aircraft systems into the national airspace system. This briefing is to inform others of the UAS-NAS FY16 progress and future directions.
    Keywords: Aeronautics (General)
    Type: DFRC-E-DAA-TN38587
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  • 7
    Publication Date: 2019-08-14
    Description: Description and Update of NASA UAS in the NAS Project
    Keywords: Aeronautics (General)
    Type: AFRC-E-DAA-TN24563 , UAS Commericalization Industry Conference; Jun 23, 2015 - Jun 25, 2015; Arlington, VA; United States
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  • 8
    Publication Date: 2019-08-13
    Description: The Visual Impairment Intracranial Pressure (VIIP) syndrome is currently NASA's number one human space flight risk. The syndrome, which is related to microgravity exposure, manifests with changes in visual acuity (hyperopic shifts, scotomas), changes in eye structure (optic disc edema, choroidal folds, cotton wool spots, globe flattening, and distended optic nerve sheaths). In some cases, elevated cerebrospinal fluid pressure has been documented postflight reflecting increased intracranial pressure (ICP). While the eye appears to be the main affected end organ of this syndrome, the ocular affects are thought to be related to the effect of cephalad fluid shift on the vascular system and the central nervous system. The leading hypotheses for the development of VIIP involve microgravity induced head-ward fluid shifts along with a loss of gravity-assisted drainage of venous blood from the brain, both leading to cephalic congestion and increased ICP. Although not all crewmembers have manifested clinical signs or symptoms of the VIIP syndrome, it is assumed that all astronauts exposed to microgravity have some degree of ICP elevation in-flight. Prolonged elevations of ICP can cause long-term reduced visual acuity and loss of peripheral visual fields, and has been reported to cause mild cognitive impairment in the analog terrestrial population of Idiopathic Intracranial Hypertension (IIH). These potentially irreversible health consequences underscore the importance of identifying the factors that lead to this syndrome and mitigating them.
    Keywords: Aerospace Medicine
    Type: JSC-CN-34816 , American Society for Gravitational and Space Research Meeting; Nov 10, 2015 - Nov 14, 2015; Alexandria, VA; United States
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  • 9
    Publication Date: 2019-07-13
    Description: Counteracting bone loss is required for future space exploration. We evaluated the ability of treadmill exercise in a LBNP chamber to counteract bone loss in a 30-day bed rest study. Eight pairs of identical twins were randomly assigned to sedentary control or exercise groups. Exercise within LBNP decreased the bone resorption caused by bed rest and may provide a countermeasure for spaceflight. INTRODUCTION: Bone loss is one of the greatest physiological challenges for extended-duration space missions. The ability of exercise to counteract weightlessness-induced bone loss has been studied extensively, but to date, it has proven ineffective. We evaluated the effectiveness of a combination of two countermeasures-treadmill exercise while inside a lower body negative pressure (LBNP) chamber-on bone loss during a 30-day bed rest study. MATERIALS AND METHODS: Eight pairs of identical twins were randomized into sedentary (SED) or exercise/LBNP (EX/LBNP) groups. Blood and urine samples were collected before, several times during, and after the 30-day bed rest period. These samples were analyzed for markers of bone and calcium metabolism. Repeated measures ANOVA was used to determine statistical significance. Because identical twins were used, both time and group were treated as repeated variables. RESULTS: Markers of bone resorption were increased during bed rest in samples from sedentary subjects, including the collagen cross-links and serum and urinary calcium concentrations. For N-telopeptide and deoxypyridinoline, there were significant (p 〈 0.05) interactions between group (SED versus EX/LBNP) and phase of the study (sample collection point). Pyridinium cross-links were increased above pre-bed rest levels in both groups, but the EX/LBNP group had a smaller increase than the SED group. Markers of bone formation were unchanged by bed rest in both groups. CONCLUSIONS: These data show that this weight-bearing exercise combined with LBNP ameliorates some of the negative effects of simulated weightlessness on bone metabolism. This protocol may pave the way to counteracting bone loss during spaceflight and may provide valuable information about normal and abnormal bone physiology here on Earth.
    Keywords: Aerospace Medicine
    Type: JSC-CN-7846 , Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research (ISSN 0884-0431); 18; 12; 2223-30
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  • 10
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Aerospace Medicine
    Type: JSC-CN-33636 , Human in Space (HIS) Symposium; Jun 27, 2015 - Jul 03, 2015; Prague; Czechoslovakia
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