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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1998

Evidence of Microfossils in Carbonaceous Chondrites

Investigations have been carried out on freshly broken, internal surfaces of the Murchison, Efremovka and Orgueil carbonaceous chondrites using Scanning Electron Microscopes (SEM) in Russia and the Environmental Scanning Electron Microscope (ESEM) in the United States. These independent studies on different samples of the meteorites have resulted in the detection of numerous spherical and ellipsoidal bodies (some with spikes) similar to the forms of uncertain biogenicity that were designated "organized elements" by prior researchers. We have also encountered numerous complex biomorphic microstructures in these carbonaceous chondrites. Many of these complex bodies exhibit diverse characteristics reminiscent of microfossils of cyanobacteria such as we have investigated in ancient phosphorites and high carbon rocks (e.g. oil shales). Energy Dispersive Spectroscopy (EDS) analysis and 2D elemental maps shows enhanced carbon content in the bodies superimposed upon the elemental distributions characteristic of the chondritic matrix. The size, distribution, composition, and indications of cell walls, reproductive and life cycle developmental stages of these bodies are strongly suggestive of biology' These bodies appear to be mineralized and embedded within the meteorite matrix, and can not be attributed to recent surface contamination effects. Consequently, we have interpreted these in-situ microstructures to represent the lithified remains of prokaryotes and filamentous cyanobacteria. We also detected in Orgueil microstructures morphologically similar to fibrous kerite crystals. We present images of many biomorphic microstructures and possible microfossils found in the Murchison, Efremovka, and Orgueil chondrites and compare these forms with known microfossils from the Cambrian phosphate-rich rocks (phosphorites) of Khubsugul, Northern Mongolia.

Hoover, Richard B.↗
NASA NTRS1987

The opportunities for space biology research on the Space Station

The life sciences research facilities for the Space Station are being designed to accommodate both animal and plant specimens for long durations studies. This will enable research on how living systems adapt to microgravity, how gravity has shaped and affected life on earth, and further the understanding of basic biological phenomena. This would include multigeneration experiments on the effects of microgravity on the reproduction, development, growth, physiology, behavior, and aging of organisms. To achieve these research goals, a modular habitat system and on-board variable gravity centrifuges, capable of holding various animal, plant, cells and tissues, is proposed for the science laboratory.

Ballard, Rodney W.↗
NASA NTRS1994

Insect gravitational biology: ground-based and shuttle flight experiments using the beetle Tribolium castaneum

Many of the traditional experimental advantages of insects recommend their use in studies of gravitational and space biology. The fruit fly, Drosophila melanogaster, is an obvious choice for studies of the developmental significance of gravity vectors because of the unparalleled description of regulatory mechanisms controlling oogenesis and embryogenesis. However, we demonstrate that Drosophila could not survive the conditions mandated for particular flight opportunities on the Space Shuttle. With the exception of Drosophila, the red flour beetle, Tribolium castaneum, is the insect best characterized with respect to molecular embryology and most frequently utilized for past space flights. We show that Tribolium is dramatically more resistant to confinement in small sealed volumes. In preparation for flight experiments we characterize the course and timing of the onset of oogenesis in newly eclosed adult females. Finally, we present results from two shuttle flights which indicate that a number of aspects of the development and function of the female reproductive system are not demonstrably sensitive to microgravity. Available information supports the utility of this insect for future studies of gravitational biology.

NASA Discipline Developmental Biology↗
NASA NTRS1990

Genetic-evolution-based optimization methods for engineering design

This paper presents the applicability of a biological model, based on genetic evolution, for engineering design optimization. Algorithms embodying the ideas of reproduction, crossover, and mutation are developed and applied to solve different types of structural optimization problems. Both continuous and discrete variable optimization problems are solved. A two-bay truss for maximum fundamental frequency is considered to demonstrate the continuous variable case. The selection of locations of actuators in an actively controlled structure, for minimum energy dissipation, is considered to illustrate the discrete variable case.

Rao, S. S.↗
NASA NTRS1993

Liquid crystalline order in mucus

Mucus plays an exceptionally wide range of important biological roles. It operates as a protective, exchange, and transport medium in the digestive, respiratory, and reproductive systems of humans and other vertebrates. Mucus is a polymer hydrogel. It is secreted as discrete packages (secretory granules) by specialized secretory cells. Mucus hydrogel is stored in a condensed state inside the secretory granules. Depending upon the architecture of their constituent macromolecules and on the composition of the solvent, polymer gels can form liquid crystalline microstructures, with orientational order being exhibited over optically resolvable distances. Individual mucin molecules consist of alternating rigid segments (heavily glycosylated; hydrophilic) and flexible segments (nonglycosylated; hydrophobic). Polymer molecules consisting of rigid units linked by flexible spacers are frequently associated with liquid crystalline behavior, which again raises the possibility that mucus could form anisotropic fluid phases. Suggestions that mucins may be self-associating in dilute solution have previously been challenged on the basis of sedimentation-equilibrium studies performed on mucus in which potential sites of association were competitively blocked with inhibitors. However, the formation of stable liquid crystalline phases does not depend on the existence of inter- or intramolecular associations; these phases can form on the basis of steric considerations alone.

NASA Discipline Number 40-20↗
NASA NTRS1975

Radio-frequency and microwave energies, magnetic and electric fields

The biological effects of radio frequency, including microwave, radiation are considered. Effects on body temperature, the eye, reproductive systems, internal organs, blood cells, the cardiovascular system, and the central nervous system are included. Generalized effects of electric and magnetic fields are also discussed. Experimentation with animals and clinical studies on humans are cited, and possible mechanisms of the effects observed are suggested.

Michaelson, S. M.↗
NASA NTRS1991

Advances in space biology and medicine. Vol. 1

Topics discussed include the effects of prolonged spaceflights on the human body; skeletal responses to spaceflight; gravity effects on reproduction, development, and aging; neurovestibular physiology in fish; and gravity perception and circumnutation in plants. Attention is also given to the development of higher plants under altered gravitational conditions; the techniques, findings, and theory concerning gravity effects on single cells; protein crystal growth in space; and facilities for animal research in space.

Bonting, Sjoerd L.↗
NASA NTRS1987

The opportunities for space biology research on the Space Station

The goals of space biology research to be conducted aboard the Space Station in 1990s include long-term studies of reproduction, development, growth, physiology, behavior, and aging in both animals and plants. They also include studies of the mechanisms by which gravitational stimuli are sensed, processed, and transmitted to a responsive site, and of the effect of microgravity on each component. The Space Station configuration will include a life sciences research facility, where experiment cyles will be on a 90-day basis (since the Space Station missions planned for the 1990s call for 90-day intervals). A modular approach is taken to accomodate animal habitats, plant growth chambers, and other specimen holding facilities; the modular habitats would be transportable between the launch systems, habitat racks, a workbench, and a variable-gravity centrifuge (included for providing artificial gravity and accurately controlled acceleration levels aboard Space Station).

Ballard, Rodney W.↗
NASA NTRS1992

USSR Space Life Sciences Digest, issue 32

This is the thirty-second issue of NASA's USSR Space Life Sciences Digest. It contains abstracts of 34 journal or conference papers published in Russian and of 4 Soviet monographs. Selected abstracts are illustrated with figures and tables from the original. The abstracts in this issue have been identified as relevant to 18 areas of space biology and medicine. These areas include: adaptation, aviation medicine, biological rhythms, biospherics, cardiovascular and respiratory systems, developmental biology, exobiology, habitability and environmental effects, human performance, hematology, mathematical models, metabolism, microbiology, musculoskeletal system, neurophysiology, operational medicine, and reproductive system.

Stone, Lydia Razran↗
NASA NTRS1974

The temporal organization of processes of cell reproduction and its connection with rhythms of radiosensitivity of the body

Radiosensitivity of individual phases of the mitotic cycle was studied in synchronous cell cultures and in several biological objects. It was found that radiosensitivity changed essentially according to phases of the mitotic cycle, depending on the kind of cells, evaluation criteria and the radiation dosage. Tests on partially synchronized HeLa cell populations, according to the criterion of survival, showed them most sensitive during mitosis, as well as in later G sub 1- or early DNA-synthesizing stages. With radiation in doses of 300 rad, the proportion of surviving cells showed a sensitivity directly before DNA synthesis of approximately 4 times higher than the later S-phase and during the major portion of G sub 1- and G sub 2-periods. Sensitivity of cells in mitosis was approximately 3 times higher than in late G sub 1- and early S-phases.

Druzhinin, Y. P.↗
NASA NTRS1990

USSR Space Life Sciences Digest, issue 28

This is the twenty-eighth issue of NASA's Space Life Sciences Digest. It contains abstracts of 60 journal papers or book chapters published in Russian and of 3 Soviet monographs. Selected abstracts are illustrated with figures and tables from the original. The abstracts in this issue have been identified as relevant to 20 areas of space biology and medicine. These areas include: adaptation, aviation medicine, botany, cardiovascular and respiratory systems, developmental biology, endocrinology, enzymology, equipment and instrumentation, hematology, human performance, immunology, life support systems, mathematical modeling, musculoskeletal system, neurophysiology, personnel selection, psychology, radiobiology, reproductive system, and space medicine.

Stone, Lydia Razran↗
NASA NTRS1993

Digest of Russian Space Life Sciences, issue 33

This is the thirty-third issue of NASA's USSR Space Life Sciences Digest. It contains abstracts of 55 papers published in Russian journals. The abstracts in this issue have been identified as relevant to the following areas of space biology and medicine: biological rhythms, body fluids, botany, cardiovascular and respiratory systems, developmental biology, endocrinology, equipment and instrumentation, gastrointestinal system, genetics, hematology, human performance, metabolism, microbiology, musculoskeletal system, neurophysiology, nutrition, operational medicine, psychology, radiobiology, and reproductive system.

Stone, Lydia Razran↗
NASA NTRS1989

USSR Space Life Sciences Digest, issue 21

This is the twenty-first issue of NASA's USSR Space Life Sciences Digest. It contains abstracts of 37 papers published in Russian language periodicals or books or presented at conferences and of a Soviet monograph on animal ontogeny in weightlessness. Selected abstracts are illustrated with figures and tables from the original. A book review of a work on adaptation to stress is also included. The abstracts in this issue have been identified as relevant to 25 areas of space biology and medicine. These areas are: adaptation, biological rhythms, body fluids, botany, cardiovascular and respiratory systems, cytology, developmental biology, endocrinology, enzymology, equipment and instrumentation, exobiology, gravitational biology, habitability and environmental effects, hematology, human performance, life support systems, mathematical modeling, metabolism, microbiology, musculoskeletal system, neurophysiology, operational medicine, perception, psychology, and reproductive system.

Hooke, Lydia Razran↗
NASA NTRS1989

CIS-lunar space infrastructure lunar technologies: Executive summary

Technologies necessary for the creation of a cis-Lunar infrastructure, namely: (1) automation and robotics; (2) life support systems; (3) fluid management; (4) propulsion; and (5) rotating technologies, are explored. The technological focal point is on the development of automated and robotic systems for the implementation of a Lunar Oasis produced by Automation and Robotics (LOAR). Under direction from the NASA Office of Exploration, automation and robotics were extensively utilized as an initiating stage in the return to the Moon. A pair of autonomous rovers, modular in design and built from interchangeable and specialized components, is proposed. Utilizing a buddy system, these rovers will be able to support each other and to enhance their individual capabilities. One rover primarily explores and maps while the second rover tests the feasibility of various materials-processing techniques. The automated missions emphasize availability and potential uses of Lunar resources, and the deployment and operations of the LOAR program. An experimental bio-volume is put into place as the precursor to a Lunar environmentally controlled life support system. The bio-volume will determine the reproduction, growth and production characteristics of various life forms housed on the Lunar surface. Physicochemical regenerative technologies and stored resources will be used to buffer biological disturbances of the bio-volume environment. The in situ Lunar resources will be both tested and used within this bio-volume. Second phase development on the Lunar surface calls for manned operations. Repairs and re-configuration of the initial framework will ensue. An autonomously-initiated manned Lunar oasis can become an essential component of the United States space program.

Faller, W.↗
NASA NTRS1989

Cislunar space infrastructure: Lunar technologies

Continuing its emphasis on the creation of a cisluar infrastructure as an appropriate and cost-effective method of space exploration and development, the University of Colorado explores the technologies necessary for the creation of such an infrastructure, namely (1) automation and robotics; (2) life support systems; (3) fluid management; (4) propulsion; and (5) rotating technologes. The technological focal point is on the development of automated and robotic systems for the implementation of a Lunar Oasis produced by automation and robotics (LOARS). Under direction from the NASA Office of Exploration, automation and robotics have been extensively utilized as an initiating stage in the return to the Moon. A pair of autonomous rovers, modular in design and built from interchangeable and specialized components, is proposed. Utilizing a 'buddy system', these rovers will be able to support each other and to enhance their individual capabilities. One rover primarily explores and maps while the second rover tests the feasibility of various materials-processing techniques. The automated missions emphasize availability and potential uses of lunar resources and the deployment and operations of the LOAR program. An experimental bio-volume is put into place as the precursor to a Lunar Environmentally Controlled Life Support System. The bio-volume will determine the reproduction, growth and production characteristics of various life forms housed on the lunar surface. Physiochemical regenerative technologies and stored resources will be used to buffer biological disturbances of the bio-volume environment. The in situ lunar resources will be both tested and used within this bio-volume. Second phase development on the lunar surface calls for manned operations. Repairs and reconfiguration of the initial framework will ensue. An autonomously initiated, manned Lunar Oasis can become an essential component of the United States space program. The Lunar Oasis will provide support to science, technology, and commerce. It will enable more cost-effective space exploration to the planets and beyond.

W. Faller↗
NASA NTRS2003

Common endocrine control of body weight, reproduction, and bone mass

Bone mass is maintained constant between puberty and menopause by the balance between osteoblast and osteoclast activity. The existence of a hormonal control of osteoblast activity has been speculated for years by analogy to osteoclast biology. Through the search for such humoral signal(s) regulating bone formation, leptin has been identified as a strong inhibitor of bone formation. Furthermore, intracerebroventricular infusion of leptin has shown that the effect of this adipocyte-derived hormone on bone is mediated via a brain relay. Subsequent studies have led to the identification of hypothalamic groups of neurons involved in leptin's antiosteogenic function. In addition, those neurons or neuronal pathways are distinct from neurons responsible for the regulation of energy metabolism. Finally, the peripheral mediator of leptin's antiosteogenic function has been identified as the sympathetic nervous system. Sympathomimetics administered to mice decreased bone formation and bone mass. Conversely, beta-blockers increased bone formation and bone mass and blunted the bone loss induced by ovariectomy.

NASA Discipline Regulatory Physiology↗
NASA NTRS1997

Plant reproduction in spaceflight environments

Because plant reproduction is a complex developmental process there are many possible sites of perturbation by the unusual environments of orbital spacecraft. Previous long-duration experiments on Soviet platforms shared features of slowed development through the vegetative stage of plant growth and aborted reproductive function. Our goal has been to understand how special features of the spaceflight environment impact physiological function and reproductive development. In a series of short-duration experiments in the Shuttle mid-deck we studied early reproductive development in Arabidopsis thaliana. Pollen and ovule development aborted at an early stage in the first experiment on STS-54 which utilized closed plant growth chambers. Post-flight analysis suggested that the plants may have been carbon dioxide limited. Subsequent experiments utilized carbon dioxide enrichment (on STS-51) and cabin air flow-through with an air exchange system (on STS-68). Both modifications allowed pollen and ovule development to occur normally on orbit, and full reproductive development up to the stage of an immature seed occurred on STS-68. However, analysis of plant roots from these experiments demonstrated a limitation in rootzone aeration in the spaceflight material that was not mitigated by these procedures. In the future, additional resources (crew time, upgraded flight hardware, and special platforms) will invite more elaborate, long-duration experimentation. On the ISS, a variable speed centrifuge and upgraded plant habitats will permit detailed experiments on the role of gravity in shaping the plant micro-environment, and what influence this plays during reproduction.

Review, Tutorial↗