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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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At least 739 records · Page 41
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Increased gluconeogenesis in hyper-G stressed rats

The role of gluconeogenesis in the altered carbohydrate metabolism in rats exposed to hyper-G stress is investigated. The blood levels of the substrates and hormones involved in gluconeogenesis were determined in rats exposed to 3.1 G for various time periods (0.25 to 24 hr). It is found that hyper-G stressed rats showed an immediate increase in plasma glucose at the onset of centrifugation which persisted throughout all the exposure periods. A substantial part of the initial rise in blood glucose is attributed to an increased rate of gluconeogenesis. An increase in liver glycogen deposition was observed in centrifuged rats as early as 0.50 hr exposure time, with progressively larger amounts accumulated as the exposure time was extended to 24 hr. It is concluded that the increase in gluconeogenic activity of hyper-G stressed rats is due to an increase in the mobilization of gluconeogenic substrates from perpheral tissues to the liver as a result of increases in circulating catecholamines and glucagon.

Daligcon, B. C.↗
NASA NTRS1983

Biochemical changes in rat liver after 18.5 days of spaceflight (41566)

The effect of weightlessness on liver metabolism was investigated using tissue from rats flown in earth orbit for 18.5 days on the Soviet Cosmos 936 biosatellite and the changes in the activities of 28 carbohydrate and lipid enzymes were determined. The activities of two enzymes, palmitoyl-CoA desaturase and lactate dehydrogenase, increased, while the activities of five, glycogen phosphorylase, 6-phosphogluconate dehydrogenase, both acyltransferases which act on alpha-glycerolphosphate and diglycerides, and and aconitate hydratase decreased. The other enzyme activities were found to be unchanged. In addition, increased levels of liver glycogen and palmitoleate were detected which probably resulted from the lowered glycogen phosphorylase and increased palmitoyl-CoA desaturase activities, respectively, in those animals that experienced weightlessness. All of the changes observed in the rats after 18.5 days of spaceflight disappear by 25 days after the flight.

Abraham, S.↗
NASA NTRS1985

Possible mechanism for changes in glycogen metabolism in unloaded soleus muscle

Carbohydrate metabolism has been shown to be affected in a number of ways by different models of hypokinesia. In vivo glycogen levels in the soleus muscle are known to be increased by short-term denervation and harness suspension. In addition, exposure to 7 days of hypogravity also caused a dramatic increase in glycogen concentration in this muscle. The biochemical alterations caused by unloading that may bring about these increases in glycogen storage in the soleus were sought.

Henriksen, E. J.↗
NASA NTRS1986

Animal studies on Spacelab-3

The flight of two squirrel monkeys and 24 rates on Spacelab-3 was the first mission to provide hand-on maintenance on animals in a laboratory environment. With few exceptions, the animals grew and behaved normally, were free of chronic stress, and differed from ground controls only for gravity-dependent parameters. One of the monkeys exhibited symptoms of space sickness similar to those observed in humans, which suggests squirrel monkeys may be good models for studying the space-adaptation syndrome. Among the wide variety of parameters measured in the rats, most notable was the dramatic loss of muscle mass and increased fragility of long bones. Other interesting rat findings were those of suppressed interferon production by spleen cells, defective release of growth hormone by somatotrophs, possible dissociation of circadian pacemakers, changes in hepatic lipid and carbohydrate metabolism, and hypersensitivity of marrow cells to erythopoietin. These results portend a strong role for animals in identifying and elucidating the physiological and anatomical responses of mammals to microgravity.

Schatte, C.↗
NASA NTRS1986

Plan for CELSS test bed project

The Closed Ecological Life Support Systems (CELSS) testbed project will achieve two major goals: It will develop the knowledge and technology needed to build and test biological or combined biological physiochemical regenerative life support systems. It will fabricate, test, and operate ground based facilities to accomplish proof-of-concent testing and evaluation leading to flight experimentation. The project will combine basic research and applied research/engineering to achieve a phased, integrated development of hardware, systems, and techniques for food and oxygen production, food processing, and waste processing in closed systems. The project will design, fabricate, and operate within three years a botanical production system scaled to a sufficient size to verify oxygen and nutrient load production (carbohydrates, fats, proteins) at a useable level. It will develop within five years a waste management system compatible with the botanical production system and a food processing system that converts available biomass into edible products. It will design, construct, and operate within ten years a ground based candidate CELSS that includes man as an active participant in the system. It will design a flight CELSS module within twelve years and construct and conduct initial flight tests within fifteen years.

Knott, W. M.↗
NASA NTRS1986

Utilization of potatoes in CELSS: Productivity and growing systems

The potato plant (solanum tuberosum L.) is one of the basic food crops that should be studied for use in NASA's closed Ecological Life Support System (CELSS). It offers high yields per unit area and time, with most of this production in the form of highly digestible carbohydrate. Potatoes, like wheat and rice, are particularly useful in human diets because of their nutritional versatility and ease of processing and preparation. The growth of the potato was studied and it was found to be a useful species for life support systems.

Tibbitts, T. W.↗
NASA NTRS1985

Possible mechanism for changes in glycogen metabolism in unloaded soleus muscle

Carbohydrate metabolism has been shown to be affected in a number of ways by different models of hypokinesia. In vivo glycogen levels in the soleus muscle are known to be increased by short-term denervation and harness suspension. In addition, exposure to 7 days of hypogravity also caused a dramatic increase in glycogen concentration in this muscle. The biochemical alterations caused by unloading that may bring about these increases in glycogen storage in the soleus were sought.

Henriksen, E. J.↗
NASA NTRS1986

Water and electrolytes

It has been found that the performance of the strongest and fittest people will deteriorate rapidly with dehydration. The present paper is concerned with the anatomy of the fluid spaces in the body, taking into account also the fluid shifts and losses during exercise and their effects on performance. Total body water is arbitrarily divided into that contained within cells (cellular) and that located outside the cells (extracellular). The anatomy of body fluid compartments is considered along with the effects of exercise on body water, fluid shifts with exercise, the consequences of sweating, dehydration and exercise, heat acclimatization and endurance training, the adverse effects of dehydration, thirst and drinking during exercise, stimuli for drinking, and water, electrolyte, and carbohydrate replacement during exercise. It is found that the deterioration of physical exercise performance due to dehydration begins when body weight decreases by about 1 percent.

Greenleaf, J. E.↗
NASA NTRS1986

On the sputter alteration of regoliths of outer solar system bodies

The present theoretical and experimental consideration of processes that are expected to occur when the porous regoliths on outer solar system bodies lacking atmospheres are subjected to energetic ion bombardment indicates that porosity reduces the effective sputtering yield of a soil by more than an order of magnitude. Between 90 and 97 percent of the sputtered atoms are trapped within the regolith and subjected to differential desorption fractionation, which emerges as the most important path for the alteration of chemical and optical properties in sputtered regoliths. Sputtered porous mixtures of water, ammonia and methane frosts suffer a loss of H, and surface reactions of C, N, and O that should yield complex hydrocarbons and carbohydrates; such reactions may have played a role in the formation of carbonaceous chondrites' matrix material prior to agglomeration.

Hapke, B.↗
NASA NTRS1986

Animal studies on Spacelab-3

Two squirrel monkeys and 24 rats were flown on Spacelab-3 to provide hands-on maintenance of animals in a laboratory environment. With few exceptions, the animals grew and behaved normally, were free of chronic stress, and differed from ground controls only for gravity-dependent parameters. One of the monkeys exhibited symptoms of space sickness similar to those observed in humans, which suggests squirrel monkeys may be good models for studying the space-adaptation syndrome. Among parameters measured in the rats, most notable is the dramatic loss of muscle mass and increased fragility of long bones. Other rat findings include suppressed interferon production by spleen cells, defective release of growth hormone by somatrophs, possible dissociation of circadian pacemakers, changes in hepatic lipid and carbohydrate metabolism, and hypersensitivity of marrow cells to erythropoietin.

Schatte, C.↗
NASA NTRS1987

Animal studies on Spacelab-3

The flight of two squirrel monkeys and 24 rats on Spacelab-3 was the first mission to provide hands-on maintenance on animals in a laboratory environment. With few exceptions, the animals grew and behaved normally, were free of chronic stress, and differed from ground controls only for gravity dependent parameters. One of the monkeys exhibited symptoms of space sickness similar to those observed in humans, which suggests squirrel monkeys may be good models for studying the space adaptation syndrome. Among the wide variety of parameters measured in the rats, most notable was the dramatic loss of muscle mass and increased fragility of long bones. Other interesting rat findings were those of suppressed interferom production by spleen cells, defective release of growth hormone by somatrophs, possible dissociation of circadian pacemakers, changes in hepatic lipid and carbohydrate metabolism, and hypersensitivity of marrow cells to erythropoietin. These results portend a strong role for animals in identifying and elucidating the physiological and anatomical responses of mammals to microgravity.

Schatte, C.↗
NASA NTRS1987

On the sputter alteration of regoliths of outer solar system bodies

Several processes that are expected to occur when the porous regoliths of outer solar system bodies (without atmospheres) are subjected to energetic ion bombardment are discussed. The conclusions reached in much of the literature addressing sputtering are quantitatively or qualitatively incorrect because effects of soil porosity have been neglected. It is shown theoretically and experimentally that porosity reduces the effective sputtering yield of a soil by more than an order of magnitude. Between 90 and 97% of the sputtered atoms are trapped within the regolith, where they are factionated by differential desorption. Experiments indicate that more volatile species have higher desorption probabilities. This process is the most important way in which alteration of chemical and optical properties occurs when a regolith is sputtered. When a basic silicate soil is irradiated these effects lead to sputter-deposited films enriched in metallic iron, while O, Na and K are preferentially lost. The Na and K are present in the atmosphere above the sputtered silicate in quantities much greater than their abundances in the regolith. Icy regoliths of SO2 should be enriched in elemental S and/or S2O. This prediction is supported by the probable identification of S2O and polysulfur oxide bands in the IR spectra of H-sputtered SO2 reported by Moore. When porous mixtures of water, ammonia and methane frosts are sputtered, the loss of H and surface reactions of C, N and O in the deposits should produce complex hydrocarbons and carbohydrates, some of which may be quite dark. Such reactions may have played a role in the formation of the matrix material of carbonaceous chondrites prior to agglomeration.

Hapke, Bruce↗
NASA NTRS1987

Application of photosynthetic N(2)-fixing cyanobacteria to the CELSS program

The feasibility of using photosynthetic microalgae (cyanobacteria) as a subsystem component for the closed ecological life support system program, with particular emphasis on the manipulation of the biomass (protein/carbohydrate) was addressed. Using factors which retard growth rates, but not photosynthetic electron flux, the partitioning of photosynthetically derived reductant may be dictated towards CO2 fixation (carbohydrate formation) and away from N2 fixation (protein formation). Cold shock treatment of fairly dense cultures markedly increases the glycogen content from 1 to 35 percent (dry weight), and presents a useful technique to change the protein/carbohydrate ratio of these organisms to a more nutritionally acceptable form.

Fry, Ian V.↗
NASA NTRS1987

Mass balances for a biological life support system simulation model

Design decisions to aid the development of future space based biological life support systems (BLSS) can be made with simulation models. The biochemistry stoichiometry was developed for: (1) protein, carbohydrate, fat, fiber, and lignin production in the edible and inedible parts of plants; (2) food consumption and production of organic solids in urine, feces, and wash water by the humans; and (3) operation of the waste processor. Flux values for all components are derived for a steady state system with wheat as the sole food source. The large scale dynamics of a materially closed (BLSS) computer model is described in a companion paper. An extension of this methodology can explore multifood systems and more complex biochemical dynamics while maintaining whole system closure as a focus.

Volk, Tyler↗
NASA NTRS1987

The determination of nutritional requirements for Safe Haven Food Supply System (emergency/survival foods)

The Space Station Safe Haven Food System must sustain 8 crew members under emergency conditions for 45 days. Emergency Survival Foods are defined as a nutritionally balanced collection of high density food and beverages selected to provide for the survival of Space Station flight crews in contingency situations. Since storage volume is limited, the foods should be highly concentrated. A careful study of different research findings regarding starvation and calorie restricted diets indicates that a minimum nutritional need close to RDA is an important factor for sustaining an individual's life in a stressful environment. Fat, protein, and carbohydrates are 3 energy producing nutrients which play a vital role in the growth and maintenance process of human life. A lower intake of protein can minimize the water intake, but it causes a negative nitrogen balance and a lower performance level. Other macro and micro nutrients are also required for nutritional interrelationships to metabolize the other 3 nutrients to their optimum level. The various options for longer duration than 45 days are under investigation.

Ahmed, Selina↗
NASA NTRS1988

Physiology of prolonged bed rest

Bed rest has been a normal procedure used by physicians for centuries in the treatment of injury and disease. Exposure of patients to prolonged bed rest in the horizontal position induces adaptive deconditioning responses. While deconditioning responses are appropriate for patients or test subjects in the horizontal position, they usually result in adverse physiological responses (fainting, muscular weakness) when the patient assume the upright posture. These deconditioning responses result from reduction in hydrostatic pressure within the cardiovascular system, virtual elimination of longitudinal pressure on the long bones, some decrease in total body metabolism, changes in diet, and perhaps psychological impact from the different environment. Almost every system in the body is affected. An early stimulus is the cephalic shift of fluid from the legs which increases atrial pressure and induces compensatory responses for fluid and electrolyte redistribution. Without countermeasures, deterioration in strength and muscle function occurs within 1 wk while increased calcium loss may continue for months. Research should also focus on drug and carbohydrate metabolism.

Greenleaf, J. E.↗
NASA NTRS1987

Mass balances for a biological life support system simulation model

Design decisions to aid the development of future space-based biological life support systems (BLSS) can be made with simulation models. Here the biochemical stoichiometry is developed for: (1) protein, carbohydrate, fat, fiber, and lignin production in the edible and inedible parts of plants; (2) food consumption and production of organic solids in urine, feces, and wash water by the humans; and (3) operation of the waste processor. Flux values for all components are derived for a steady-state system with wheat as the sole food source.

Volk, Tyler↗