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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS2001

Regulation of PGE(2) and PGI(2) release from human umbilical vein endothelial cells by actin cytoskeleton

Disruption of microfilaments in human umbilical vein endothelial cells (HUVEC) with cytochalasin D (cytD) or latrunculin A (latA) resulted in a 3.3- to 5.7-fold increase in total synthesis of prostaglandin E(2) (PGE(2)) and a 3.4- to 6.5-fold increase in prostacyclin (PGI(2)) compared with control cells. Disruption of the microtubule network with nocodazole or colchicine increased synthesis of PGE(2) 1.7- to 1.9-fold and PGI(2) 1.9- to 2.0-fold compared with control cells. Interestingly, however, increased release of PGE(2) and PGI(2) from HUVEC into the media occurred only when microfilaments were disrupted. CytD treatment resulted in 6.7-fold more PGE(2) and 3.8-fold more PGI(2) released from HUVEC compared with control cells; latA treatment resulted in 17.7-fold more PGE(2) and 11.2-fold more PGI(2) released compared with control cells. Both increased synthesis and release of prostaglandins in response to all drug treatments were completely inhibited by NS-398, a specific inhibitor of cyclooxygenase-2 (COX-2). Disruption of either microfilaments using cytD or latA or of microtubules using nocodazole or colchicine resulted in a significant increase in COX-2 protein levels, suggesting that the increased synthesis of prostaglandins in response to drug treatments may result from increased activity of COX-2. These results, together with studies demonstrating a vasoprotective role for prostaglandins, suggest that the cytoskeleton plays an important role in maintenance of endothelial barrier function by regulating prostaglandin synthesis and release from HUVEC.

Non-NASA Center↗
NASA NTRS1999

Systems Engineering Design Via Experimental Operation Research: Complex Organizational Metric for Programmatic Risk Environments (COMPRE)

Unique and innovative graph theory, neural network, organizational modeling, and genetic algorithms are applied to the design and evolution of programmatic and organizational architectures. Graph theory representations of programs and organizations increase modeling capabilities and flexibility, while illuminating preferable programmatic/organizational design features. Treating programs and organizations as neural networks results in better system synthesis, and more robust data modeling. Organizational modeling using covariance structures enhances the determination of organizational risk factors. Genetic algorithms improve programmatic evolution characteristics, while shedding light on rulebase requirements for achieving specified technological readiness levels, given budget and schedule resources. This program of research improves the robustness and verifiability of systems synthesis tools, including the Complex Organizational Metric for Programmatic Risk Environments (COMPRE).

Mog, Robert A.↗
NASA NTRS1991

Proceedings of the Second Joint Technology Workshop on Neural Networks and Fuzzy Logic, volume 2

Documented here are papers presented at the Neural Networks and Fuzzy Logic Workshop sponsored by NASA and the University of Texas, Houston. Topics addressed included adaptive systems, learning algorithms, network architectures, vision, robotics, neurobiological connections, speech recognition and synthesis, fuzzy set theory and application, control and dynamics processing, space applications, fuzzy logic and neural network computers, approximate reasoning, and multiobject decision making.

Lea, Robert N.↗
NASA NTRS1991

Proceedings of the Second Joint Technology Workshop on Neural Networks and Fuzzy Logic, volume 1

Documented here are papers presented at the Neural Networks and Fuzzy Logic Workshop sponsored by NASA and the University of Houston, Clear Lake. The workshop was held April 11 to 13 at the Johnson Space Flight Center. Technical topics addressed included adaptive systems, learning algorithms, network architectures, vision, robotics, neurobiological connections, speech recognition and synthesis, fuzzy set theory and application, control and dynamics processing, space applications, fuzzy logic and neural network computers, approximate reasoning, and multiobject decision making.

Lea, Robert N.↗
NASA NTRS1993

Proceedings of the Third International Workshop on Neural Networks and Fuzzy Logic, volume 2

Papers presented at the Neural Networks and Fuzzy Logic Workshop sponsored by the National Aeronautics and Space Administration and cosponsored by the University of Houston, Clear Lake, held 1-3 Jun. 1992 at the Lyndon B. Johnson Space Center in Houston, Texas are included. During the three days approximately 50 papers were presented. Technical topics addressed included adaptive systems; learning algorithms; network architectures; vision; robotics; neurobiological connections; speech recognition and synthesis; fuzzy set theory and application, control and dynamics processing; space applications; fuzzy logic and neural network computers; approximate reasoning; and multiobject decision making.

Culbert, Christopher J.↗
NASA NTRS1993

Proceedings of the Third International Workshop on Neural Networks and Fuzzy Logic, volume 1

Documented here are papers presented at the Neural Networks and Fuzzy Logic Workshop sponsored by the National Aeronautics and Space Administration and cosponsored by the University of Houston, Clear Lake. The workshop was held June 1-3, 1992 at the Lyndon B. Johnson Space Center in Houston, Texas. During the three days approximately 50 papers were presented. Technical topics addressed included adaptive systems; learning algorithms; network architectures; vision; robotics; neurobiological connections; speech recognition and synthesis; fuzzy set theory and application, control, and dynamics processing; space applications; fuzzy logic and neural network computers; approximate reasoning; and multiobject decision making.

Culbert, Christopher J.↗
NASA NTRS1987

Neural network based speech synthesizer: A preliminary report

A neural net based speech synthesis project is discussed. The novelty is that the reproduced speech was extracted from actual voice recordings. In essence, the neural network learns the timing, pitch fluctuations, connectivity between individual sounds, and speaking habits unique to that individual person. The parallel distributed processing network used for this project is the generalized backward propagation network which has been modified to also learn sequences of actions or states given in a particular plan.

Villarreal, James A.↗
NASA NTRS1978

Controlled cellular energy conversion in brown adipose tissue thermogenesis

Brown adipose tissue serves as a model system for nonshivering thermogenesis (NST) since a) it has as a primary physiological function the conversion of chemical energy to heat; and b) preliminary data from other tissues involved in NST (e.g., muscle) indicate that parallel mechanisms may be involved. Now that biochemical pathways have been proposed for brown fat thermogenesis, cellular models consistent with a thermodynamic representation can be formulated. Stated concisely, the thermogenic mechanism in a brown fat cell can be considered as an energy converter involving a sequence of cellular events controlled by signals over the autonomic nervous system. A thermodynamic description for NST is developed in terms of a nonisothermal system under steady-state conditions using network thermodynamics. Pathways simulated include mitochondrial ATP synthesis, a Na+/K+ membrane pump, and ionic diffusion through the adipocyte membrane.

Horowitz, J. M.↗
NASA NTRS1979

Lunar building materials: Some considerations on the use of inorganic polymers

The use of inorganic polymer systems synthesized from the available lunar chemical elements, viz., silicon, aluminum, and oxygen to make adhesives, binders, and sealants needed in the fabrication of lunar building materials and the assembly of structures is considered. Inorganic polymer systems, their background, status, and shortcomings, and the use of network polymers as a possible approach to synthesis are examined as well as glassy metals for unusual structural strength, and the use of cold-mold materials as well as foam-sintered lunar silicates for lightweight shielding and structural building materials.

Lee, S. M.↗
NASA NTRS2003

Biomimetic, Self-Healing Nanocomposites for Aerospace Applications

This final report contains a summary of significant findings, and bibliographies of publications and patents resulting from the research. The findings are grouped as follows: A) Lustrin-Mimetic Self-Healing Polymer Networks; B) Nanostructure-Directing Catalysis of Synthesis of Electronically and Optoelectronically Active Metallo-oxanes and Organometallics; C) New Discovery that Molecular Stencils Control Directional Growth to Form Light-Weight Mineral Foams.

Morse, Daniel E.↗
NASA NTRS2005

Automated Synthesis of Long Communication Delays for Testing

Planetary-Ohio Network Emulator (p- ONE) is a computer program for local laboratory testing of high bandwidth data-communication systems subject to long delays in propagation over interplanetary distances. p-ONE is installed on a personal computer connected to two bidirectional Ethernet interfaces, denoted A and B, that represent local-area networks at opposite ends of a long propagation path. Traffic that is to be passed between A and B is encapsulated in IP (Internet Protocol) packets (e.g., User Data Protocol, UDP). Intercepting this traffic between A and B in both directions, p-ONE time-tags each packet and stores it in memory or on the hard disk of the computer for a user-specified interval that equals the propagation delay to be synthesized. At the expiration of its storage time, each such packet is sent to its destination (that is, if it was received from A, it is sent to B, or vice versa). The accuracy of the p-ONE software is very high, with zero packet loss through the system and negligible latency. Optionally, p-ONE can be configured to delay all network traffic to and from all network addresses on each Ethernet interface or to selectively delay traffic between specific addresses or traffic of specific types. p-ONE works well with Linux and is also designed to be compatible with other operating systems.

Seibert, Marc↗
NASA NTRS1985

Random and block copolymerization in metal oxide gel synthesis from metalorganic compounds

The introduction and development of the block copolymerization concept in metal oxide gel synthesis will in the future generate a new class of glass/microcrystalline materials. By the year 2004, better scientific understanding of the chemical principles controlling the distribution of network formers or modifiers in silicate gels will permit the synthesis of architecturally well-defined block polymers with unique high-performance behavior.

Mukherjee, S. P.↗