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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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The impact of the biodegradation rate of ammonium perchlorate on the environment was studied in terms of growth, metabolic rate, and total biomass of selected animal and plant species. Brief methodology and detailed results are presented.
Methodological techniques for determining biomass and energy contents by calorimetry and metabolic rates - marine biology
Scientific requirements necessary to develop a spectral analyzer for monitoring mammalian subjects, are discussed. The analyzer measures dynamic or time dependent data as a measure of the subjects operating status. Measurable data include metabolic rate, body temperature, and blood constituents like glucose, oxygen, and carbon dioxide, and lactic acid. Metabolic cycles were found with periodicities in the range of minutes and hours; longer cycles in body weight (3 1/2 days and 60 days), indicative of metabolic processes, were also found.
Effects of diluent gases on the metabolism of animals breathing nitrogen-oxygen, argon-oxygen, and helium-oxygen mixtures were studied. Results show that helium actually affected the mean free path of oxygen across the alveoli and increased metabolic rate. It is speculated that it might be necessary to keep an astronaut in a depressed metabolic state during prolonged space flight by using an argon-oxygen or a xenon-nitrogen mixture for breathing. Replacement of the depressant gases during periods requiring critical spacecraft maneuvers by neon-oxygen mixtures would insure maximal performance.
The effect of salinity stress on metabolic heat output of barley (Hordeum vulgare L.) root tips was measured by isothermal microcalorimetry. Several varieties differing in tolerance to salinity were compared and differences quantified. Two levels of inhibition by increasing salt were found. Following the transition from the initial rate of the first level, inhibition remained at about 50% with further increases in salt concentration up to 150 millimolar. The concentration of salt required to inhibit to this level was cultivar dependent. At highter concentrations (>150 millimolar) of salt, metabolism was further decreased. This decrease was not cultivar dependent. The decreased rate of metabolic heat output at the first transition could be correlated with decreases in uptake of NO3-, NH4+, and Pi that occurred as the salt concentration was increased. The high degree of dependence of the inhibition of metabolic heat output on NaCl concentration points to a highly cooperative reaction responsible for the general inhibition of metabolism and nutrient uptake. The time required to attain the first level of salt inhibition is less than 20 minutes. Inhibition of root tips was not reversible by washing with salt free solutions. In addition to revealing these features of salt inhibition, isothermal microcalorimetry is a promising method for convenient and rapid determination of varietal differences in response to increasing salinity.
Assessment of the metabolic consequences of exposure to elevated partial pressures of nitrogen and helium under normobaric and hyperbaric conditions in goats. The results include the finding that hyperbaric nitrogen causes and increase in metabolic rate and a general decrease in blood constituent levels which is interpreted as reflecting a shift toward fatty acid metabolism at the expense of carbohydrates. A similar but more pronounced pattern was observed with hyperbaric helium.
Experiments describing the mechanism of inert gas narcosis are reported. A strain of mice, genetically altered to increase susceptibility to botulin poisoning (synaptic response) appears to increase metabolic rates while breathing argon; this infers a genetically altered synaptic response to both botulin toxin and narcotic gases. Studies of metabolic depression in human subjects breathing either air or a 30% mixture of nitrous oxide indicate that nitrous oxide narcosis does not produce pronounced metabolic depression. Tests on mice for relative susceptibilities to narcosis and oxygen poisoning as a function of fatty membrane composition show that alteration of the fatty acid composition of phospholipids increases resistance to metabolically depressant effects of argon but bas no effect on nitrous oxide narcosis. Another study suggests that acclimatization to low tension prior to high pressure oxygen treatment enhances susceptibility of mice to convulsions and death; developing biochemical lesions cause CNS metabolite reductions and pulmonary damage.
SpaceWorks Enterprises, Inc. (SEI) has conducted an evaluation of an advanced habitat system designed to transportcrews between the Earth and Mars. This new and innovative habitat concept is capable of placing crew members ininactive, torpor states during transit phases of a deep space mission. This substantially reduces the mass and size ofthe habitat, which ultimately leads to significant reductions in the overall architecture size.Our approach for achieving this is based on extending the current and evolving medical practice of TherapeuticHypothermia (TH) - a proven and effective treatment for various traumatic injuries. TH is a medical treatment thatlowers a patient's body temperature by just 5 to 10 degrees Fahrenheit causing human metabolic rate to decreasesignificantly and the body to enter an unconscious state. This method avoids the intractable challenges often associatedwith cell metabolic cessation through cryogenic freezing and other highly speculative approaches.The initial results obtained from the research and analysis conducted in the Phase I effort warranted further study ofthis concept and technology. The specific objectives of the continued work include:1. Addressing critical medical aspects and risks for inducing torpor via Therapeutic Hypothermia and theapproach for providing nutrition and hydration for the crew during torpor. 2. Focusing on mitigation aspects and technology potential for solving key human spaceflight challenges. 3. Addressing critical engineering aspects of the design that may impact the initial performance and cost resultsobtained in Phase I. 4. Examining the broader extensibility and enabling capabilities of this concept through applicability toadditional exploration missions beyond Mars. 5. Establishing a technology development roadmap, addressing both medical and engineering aspects, thatindicate a logical and scientifically achievable path forward for maturation of this technology.
In order to measure astronauts' metabolic rates in space, Glenn Research Center partnered with Case Western University and the Cleveland Clinic to develop the Portable Unit for Metabolic Analysis (PUMA). Cleveland-based Orbital Research licensed and then modified PUMA to help the US Navy assess pilot oxygen problems and is now designing a device that can be used in hospitals.
Microbes need resources for energy and cellular building material. They also need access to clement conditions with liquid water and a cellular damage rate that is lower than repair. When deprived of resources and clement conditions, microbes often enter some form of dormancy (e.g., by ceasing cell division, slowing metabolic rate, or forming an endospore) until they can grow again. For example, at night, phototrophs wait for the sun to return. In winter, soil microbes wait for warmer temperatures. Microbes that cause diseases like tuberculosis can stay dormant for years, waiting for the cessation of antibiotic or immune system bombardment. But what about longer timescales? Unlike multicellular life, microbes survive in an extremely broad range of conditions and can access an amazing variety of resources to maintain cellular functions in the absence of cell division. This means that they have the potential to be dormant for much longer than a few months or years. There is no theoretical reason microbes cannot survive on maintenance energy for hundreds or thousands of years, or longer, with little to no cell proliferation. Here, given this lack of theoretical constraints on the length of microbial dormancy intervals, two questions arise, (i) is there evidence for the existence of organisms experiencing very long dormancies? And (ii) what could be the advantages of such long wait times?
Abstract Hydraulic fracturing has unlocked vast amounts of hydrocarbons trapped within unconventional shale formations. This large-scale engineering approach inadvertently introduces microorganisms into the hydrocarbon reservoir, allowing them to inhabit a new physical space and thrive in the unique biogeochemical resources present in the environment. Advancing our fundamental understanding of microbial growth and physiology in this extreme subsurface environment is critical to improving biofouling control efficacy and maximizing opportunities for beneficial natural resource exploitation. Here, we used metaproteomics and exometabolomics to investigate the biochemical mechanisms underpinning the adaptation of model bacterium Halanaerobium congolense WG10 and mixed microbial consortia enriched from shale-produced fluids to hypersalinity and very low reservoir flow rates (metabolic stress). We also queried the metabolic foundation for biofilm formation in this system, a major impediment to subsurface energy exploration. For the first time, we report that H. congolense WG10 accumulates tyrosine for osmoprotection, an indication of the flexible robustness of stress tolerance that enables its long-term persistence in fractured shale environments. We also identified aromatic amino acid synthesis and cell wall maintenance as critical to biofilm formation. Finally, regulation of transmembrane transport is key to metabolic stress adaptation in shale bacteria under very low well flow rates. These results provide unique insights that enable better management of hydraulically fractured shale systems, for more efficient and sustainable energy extraction.
Temperature dependence of maturation and metabolic rates in insects, and the failure of vital processes during development were investigated. The paper presented advances the general hypothesis that aging in biological systems is a consequence of the production of entropy concomitant with metabolic activity.
Changes in the physiological indices of respiration, respiratory metabolism and energy consumption in spacecrews under weightlessness conditions manifest themselves in increased metabolic rates, higher pulmonary ventilation volume, oxygen consumption and carbon dioxide elimination, energy consumption levels in proportion to reduction in neuroemotional and psychic stress, adaptation to weightlessness and work-rest cycles, and finally in a relative stabilization of metabolic processes due to hemodynamic shifts.
The Launch and Entry Suit (LES) has been worn by astronauts since 1988 for Space Shuttle launch and landing. Previous work indicated that carbon dioxide (CO2) accumulation in the LES non-conformal helmet might be high during locomotion while wearing the LES. The purpose of this study was to characterize the inspired CO2%, metabolic requirements, and egress performance during a simulation of an unaided egress from the Space Shuttle in healthy male subjects wearing the LES and walking on a treadmill. With the helmet visor closed, 12 male subjects completed a 6-min seated prebreathe with 100% O2 followed by a 2-min stand and 5 min of walking at 1.56 m/sec (5.6 km/h, 3.5 mph) as a simulation of unaided egress. All subjects walked with four different G-suit pressures (0.0, 0.5, 1.0, 1.5 psi). After a 10-min recovery, subjects walked 5 min with the same G-suit pressure and helmet visor open for the measurement of metabolic rate (VO2). When G-suit inflation levels were 1.0 or 1.5 psi, only 4 of our 12 healthy, non-micro-gravity exposed subjects completed the unaided egress. Inspired CO2 levels greater than 4% were routinely observed during walking. The metabolic cost at the 1.5 psi G-suit inflation was over 135% of the metabolic cost at 0.0 psi inflation. During unaided egress, G-suit inflation pressures of 1.0 (required inflation for missions greater than 11 days) and 1.5 psi resulted in elevated CO2 in the LES helmet and increased metabolic cost of walking, either of which could impact unaided egress by returning space flight crews.
Anthropogenic increases in nitrogen (N) and phosphorus (P) concentrations can strongly influence the structure and function of ecosystems. Even though lotic ecosystems receive cumulative inputs of nutrients applied to and deposited on land, no comprehensive assessment has quantified nutrient-enrichment effects within streams and rivers. We conducted a meta-analysis of published studies that experimentally increased concentrations of N and/or P in streams and rivers to examine how enrichment alters ecosystem structure (state: primary producer and consumer biomass and abundance) and function (rate: primary production, leaf breakdown rates, metabolism) at multiple trophic levels (primary producer, microbial heterotroph, primary and secondary consumers, and integrated ecosystem). Our synthesis included 184 studies, 885 experiments, and 3497 biotic responses to nutrient enrichment. We documented widespread increases in organismal biomass and abundance (mean response = +48%) and rates of ecosystem processes (+54%) to enrichment across multiple trophic levels, with no large differences in responses among trophic levels or between autotrophic or heterotrophic food-web pathways. Responses to nutrient enrichment varied with the nutrient added (N, P, or both) depending on rate versus state variable and experiment type, and were greater in flume and whole-stream experiments than in experiments using nutrient-diffusing substrata. Generally, nutrient-enrichment effects also increased with water temperature and light, and decreased under elevated ambient concentrations of inorganic N and/or P. Overall, increased concentrations of N and/or P altered multiple food-web pathways and trophic levels in lotic ecosystems. Finally, our results indicate that preservation or restoration of biodiversity and ecosystem functions of streams and rivers requires management of nutrient inputs and consideration of multiple trophic pathways.
A multi-year effort has been carried out at NASA-JSC to develop an advanced extra-vehicular activity Portable Life Support System (PLSS) design intended to further the current state of the art by increasing operational flexibility, reducing consumables, and increasing robustness. Previous efforts have focused on modeling and analyzing the advanced PLSS architecture, as well as developing key enabling technologies. Like the current International Space Station Extra-vehicular Mobility Unit PLSS, the advanced PLSS comprises three subsystems required to sustain the crew during extra-vehicular activity including the Thermal, Ventilation, and Oxygen Subsystems. This multi-year effort has culminated in the construction and operation of PLSS 1.0, a test bed that simulates full functionality of the advanced PLSS design. PLSS 1.0 integrates commercial off the shelf hardware with prototype technology development components, including the primary and secondary oxygen regulators, Ventilation Subsystem fan, Rapid Cycle Amine swingbed carbon dioxide and water vapor removal device, and Spacesuit Water Membrane Evaporator heat rejection device. The overall PLSS 1.0 test objective was to demonstrate the capability of the Advanced PLSS to provide key life support functions including suit pressure regulation, carbon dioxide and water vapor removal, thermal control and contingency purge operations. Supplying oxygen was not one of the specific life support functions because the PLSS 1.0 test was not oxygen rated. Nitrogen was used for the working gas. Additional test objectives were to confirm PLSS technology development components performance within an integrated test bed, identify unexpected system level interactions, and map the PLSS 1.0 performance with respect to key variables such as crewmember metabolic rate and suit pressure. Successful PLSS 1.0 testing completed 168 test points over 44 days of testing and produced a large database of test results that characterize system level and component performance. With the exception of several minor anomalies, the PLSS 1.0 test rig performed as expected; furthermore, many system responses trended in accordance with pre-test predictions.
Red blood cell (RBC) survival was prolonged in hypophysectomized rats. While the rate of random hemolysis was decreased in some hypophysectomized hosts, in all directly injected and cross-transfused hypophysectomized rat hosts, there was a significant prolongation of the phase of senescent death. In contrast, RBCs from hypophysectomized donors survived normally in normal hosts. These experiments are further evidence of a relationship between RBC aging and metabolic rate, and suggest an intimate involvement with the calorigenic hormones.
Thermal balance between heat removal and metabolic rate in pressurized Gemini G2-C full pressure suit at two barometric pressures