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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Implementation of a state of the art automated system for the production of cloud/water vapor motion winds from geostationary satellites

The thrust of the proposed effort under this contract is aimed at improving techniques to track water vapor data in sequences of imagery from geostationary satellites. In regards to this task, significant testing, evaluation, and progress was accomplished during this period. Sets of winds derived from Meteosat data were routinely produced during Atlantic hurricane events in the 1993 season. These wind sets were delivered via Internet in real time to the Hurricane Research Division in Miami for their evaluation in a track forecast model. For eighteen cases in which 72-hour forecasts were produced, thirteen resulted in track forecast improvements (some quite significant). In addition, quality-controlled Meteosat water vapor winds produced by NESDIS were validated against rawinsondes, yielding an 8 m/s RMS. This figure is comparable to upper-level cloud drift wind accuracies. Given the complementary horizontal coverage in cloud-free areas, we believe that water vapor vectors can supplement cloud-drift wind information to provide good full-disk coverage of the upper tropospheric flow. The impact of these winds on numerical analysis and forecasts will be tested in the next reporting period.

Velden, Christopher S.↗
NASA NTRS2003

The potato virus X TGBp2 protein association with the endoplasmic reticulum plays a role in but is not sufficient for viral cell-to-cell movement

Potato virus X (PVX) TGBp1, TGBp2, TGBp3, and coat protein are required for virus cell-to-cell movement. Plasmids expressing GFP fused to TGBp2 were bombarded to leaf epidermal cells and GFP:TGBp2 moved cell to cell in Nicotiana benthamiana leaves but not in Nicotiana tabacum leaves. GFP:TGBp2 movement was observed in TGBp1-transgenic N. tabacum, indicating that TGBp2 requires TGBp1 to promote its movement in N. tabacum. In this study, GFP:TGBp2 was detected in a polygonal pattern that resembles the endoplasmic reticulum (ER) network. Amino acid sequence analysis revealed TGBp2 has two putative transmembrane domains. Two mutations separately introduced into the coding sequences encompassing the putative transmembrane domains within the GFP:TGBp2 plasmids and PVX genome, disrupted membrane binding of GFP:TGBp2, inhibited GFP:TGBp2 movement in N. benthamiana and TGBp1-expressing N. tabacum, and inhibited PVX movement. A third mutation, lying outside the transmembrane domains, had no effect on GFP:TGBp2 ER association or movement in N. benthamiana but inhibited GFP:TGBp2 movement in TGBp1-expressing N. tabacum and PVX movement in either Nicotiana species. Thus, ER association of TGBp2 may be required but not be sufficient for virus movement. TGBp2 likely provides an activity for PVX movement beyond ER association.

NASA Discipline Plant Biology↗
NASA NTRS2003

Isolation and characterization of a novel gene sfig in rat skeletal muscle up-regulated by spaceflight (STS-90)

We obtained the skeletal muscle of rats exposed to weightless conditions during a 16-day-spaceflight (STS-90). By using a differential display technique, we identified 6 up-regulated and 3 down-regulated genes in the gastrocnemius muscle of the spaceflight rats, as compared to the ground control. The up-regulated genes included those coding Casitas B-lineage lymphoma-b, insulin growth factor binding protein-1, titin and mitochondrial gene 16 S rRNA and two novel genes (function unknown). The down-regulated genes included those encoding RNA polymerase II elongation factor-like protein, NADH dehydrogenase and one novel gene (function unknown). In the present study, we isolated and characterized one of two novel muscle genes that were remarkably up-regulated by spaceflight. The deduced amino acid sequence of the spaceflight-induced gene (sfig) comprises 86 amino acid residues and is well conserved from Drosophila to Homo sapiens. A putative leucine-zipper structure located at the N-terminal region of sfig suggests that this gene may encode a transcription factor. The up-regulated expression of this gene, confirmed by Northern blot analysis, was observed not only in the muscles of spaceflight rats but also in the muscles of tail-suspended rats, especially in the early stage of tail-suspension when gastrocnemius muscle atrophy initiated. The gene was predominantly expressed in the kidney, liver, small intestine and heart. When rat myoblastic L6 cells were grown to 100% confluence in the cell culture system, the expression of sfig was detected regardless of the cell differentiation state. These results suggest that spaceflight has many genetic effects on rat skeletal muscle.

STS-90 Shuttle Project↗
NASA NTRS1999

Mutations in a new Arabidopsis cyclophilin disrupt its interaction with protein phosphatase 2A

The heterotrimeric protein phosphatase 2A (PP2A) is a component of multiple signaling pathways in eukaryotes. Disruption of PP2A activity in Arabidopsis is known to alter auxin transport and growth response pathways. We demonstrated that the regulatory subunit A of an Arabidopsis PP2A interacts with a novel cyclophilin, ROC7. The gene for this cyclophilin encodes a protein that contains a unique 30-amino acid extension at the N-terminus, which distinguishes the gene product from all previously identified Arabidopsis cyclophilins. Altered forms of ROC7 cyclophilin with mutations in the conserved DENFKL domain did not bind to PP2A. Unlike protein phosphatase 2B, PP2A activity in Arabidopsis extracts was not affected by the presence of the cyclophilin-binding molecule cyclosporin. The ROC7 transcript was expressed to high levels in all tissues tested. Expression of an ROC7 antisense transcript gave rise to increased root growth. These results indicate that cyclophilin may have a role in regulating PP2A activity, by a mechanism that differs from that employed for cyclophilin regulation of PP2B.

NASA Discipline Plant Biology↗
NASA NTRS1996

Characterization of individual polynucleotide molecules using a membrane channel

We show that an electric field can drive single-stranded RNA and DNA molecules through a 2.6-nm diameter ion channel in a lipid bilayer membrane. Because the channel diameter can accommodate only a single strand of RNA or DNA, each polymer traverses the membrane as an extended chain that partially blocks the channel. The passage of each molecule is detected as a transient decrease of ionic current whose duration is proportional to polymer length. Channel blockades can therefore be used to measure polynucleotide length. With further improvements, the method could in principle provide direct, high-speed detection of the sequence of bases in single molecules of DNA or RNA.

NASA Discipline Exobiology↗
NASA NTRS1996

Fibronectin regulates calvarial osteoblast differentiation

The secretion of fibronectin by differentiating osteoblasts and its accumulation at sites of osteogenesis suggest that fibronectin participates in bone formation. To test this directly, we determined whether fibronectin-cell interactions regulate progressive differentiation of cultured fetal rat calvarial osteoblasts. Spatial distributions of alpha 5 integrin subunit, fibronectin, osteopontin (bone sialoprotein I) and osteocalcin (bone Gla-protein) were similar in fetal rat calvaria and mineralized, bone-like nodules formed by cultured osteoblasts. Addition of anti-fibronectin antibodies to cultures at confluence reduced subsequent formation of nodules to less than 10% of control values, showing that fibronectin is required for normal nodule morphogenesis. Anti-fibronectin antibodies selectively inhibited steady-state expression of mRNA for genes associated with osteoblast differentiation; mRNA levels for alkaline phosphatase and osteocalcin were suppressed, whereas fibronectin, type I collagen and osteopontin were unaffected. To identify functionally relevant domains of fibronectin, we treated cells with soluble fibronectin fragments and peptides. Cell-binding fibronectin fragments (type III repeats 6-10) containing the Arg-Gly-Asp (RGD) sequence blocked both nodule initiation and maturation, whether or not they contained a functional synergy site. In contrast, addition of the RGD-containing peptide GRGDSPK alone did not inhibit nodule initiation, although it did block nodule maturation. Thus, in addition to the RGD sequence, other features of the large cell-binding fragments contribute to the full osteogenic effects of fibronectin. Nodule formation and osteoblast differentiation resumed after anti-fibronectin antibodies or GRGDSPK peptides were omitted from the media, showing that the inhibition was reversible and the treatments were not cytotoxic. Outside the central cell-binding domain, peptides from the IIICS region and antibodies to the N terminus did not inhibit nodule formation. We conclude that osteoblasts interact with the central cell-binding domain of endogenously produced fibronectin during early stages of differentiation, and that these interactions regulate both normal morphogenesis and gene expression.

NASA Program Space Physiology and Countermeasures↗
NASA NTRS2010

The Orion GN and C Data-Driven Flight Software Architecture for Automated Sequencing and Fault Recovery

The Orion Crew Exploration Vehicle (CET) is being designed to include significantly more automation capability than either the Space Shuttle or the International Space Station (ISS). In particular, the vehicle flight software has requirements to accommodate increasingly automated missions throughout all phases of flight. A data-driven flight software architecture will provide an evolvable automation capability to sequence through Guidance, Navigation & Control (GN&C) flight software modes and configurations while maintaining the required flexibility and human control over the automation. This flexibility is a key aspect needed to address the maturation of operational concepts, to permit ground and crew operators to gain trust in the system and mitigate unpredictability in human spaceflight. To allow for mission flexibility and reconfrgurability, a data driven approach is being taken to load the mission event plan as well cis the flight software artifacts associated with the GN&C subsystem. A database of GN&C level sequencing data is presented which manages and tracks the mission specific and algorithm parameters to provide a capability to schedule GN&C events within mission segments. The flight software data schema for performing automated mission sequencing is presented with a concept of operations for interactions with ground and onboard crew members. A prototype architecture for fault identification, isolation and recovery interactions with the automation software is presented and discussed as a forward work item.

King, Ellis↗
NASA NTRS2005

Data visualization for effective rover sequencing

The Rover Sequencing and Visualization Program is a suite of toos for the commanding of planetary rovers which are subject to significant light time delay and thus are unsuitable for tele-operation.

surface operations↗
NASA NTRS1991

Geomagnetic model investigations for 1980 - 1989: A model for strategic defense initiative particle beam experiments and a study in the effects of data types and observatory bias solutions

Two suites of geomagnetic field models were generated at the request of Los Alamos National Lab. concerning Strategic Defense Initiative (SDI) research. The first is a progression of five models incorporating MAGSAT data and data from a sequence of batches as a priori information. The batch sequence is: post 1979.5 observatory data, post 1980 land survey and selected aeromagnetic and marine survey data, a special White Sands (NM) area survey by Project Magnet with some additional post 1980 marine survey data, and finally DE-2 satellite data. These models are of 13th deg and order in their main field terms, and deg and order 10 in their first derivative temporal terms. The second suite consists of four models based solely upon post 1983.5 observatory and survey data. They are of deg and order 10 in main field and 8 in a first deg Taylor series. A comprehensive error analysis was applied to both series, which accounted for error sources such as the truncated core and crustal fields, and the neglected Sq and low deg crustal fields. Comparison of the power spectrum of the MGST (10/81) model with those of this series show good agreement.

Langel, Robert A.↗
NASA NTRS2002

Testing putative hemichordate homologues of the chordate dorsal nervous system and endostyle: expression of NK2.1 (TTF-1) in the acorn worm Ptychodera flava (Hemichordata, Ptychoderidae)

Recent phylogenetic investigations have confirmed that hemichordates and echinoderms are sister taxa. However, hemichordates share several cardinal characterstics with chordates and are thus an important taxon for testing hypotheses of homology between key chordate characters and their putative hemichordate antecedents. The chordate dorsal nervous system (DNS) and endostyle are intriguing characters because both hemichordate larval and adult structures have been hypothesized as homologues. This study attempts to test these purported homologies through examination of the expression pattem of a Ptychodera flava NK2 gene, PfNK2.1, because this gene is expressed both in the DNS and endostyle/thyroid in a wide range of chordate taxa. We found that PfNK2.1 is expressed in both neuronal and pharyngeal structures, but its expression pattem is broken up into distinct embryonic and juvenile phases. During embryogenesis, PfNK2.1 is expressed in the apical ectoderm, with transcripts later detected in presumable neuronal structures, including the apical organ and ciliated feeding band. In the developing juvenile we detected PfNK2.1 signal throughout the pharynx, including the stomochord, and later in the hindgut. We conclude that the similar utilization of NK2.1 in apical organ development and chordate DNS is probably due to a more general role for NK2.1 in neurogenesis and that hemichordates do not possess a homologue of the chordate DNS. In addition, we conclude that P. flava most likely does not possess a true endostyle; rather during the evolution of the endostyle NK2.1 was recruited from its more general role in pharynx development.

NASA Discipline Evolutionary Biology↗
NASA NTRS2000

Cloning and characterization of ftsZ and pyrF from the archaeon Thermoplasma acidophilum

To characterize cytoskeletal components of archaea, the ftsZ gene from Thermoplasma acidophilum was cloned and sequenced. In T. acidophilum ftsZ, which is involved in cell division, was found to be in an operon with the pyrF gene, which encodes orotidine-5'-monophosphate decarboxylase (ODC), an essential enzyme in pyrimidine biosynthesis. Both ftsZ and pyrF from T. acidophilum were expressed in Escherichia coli and formed functional proteins. FtsZ expression in wild-type E. coli resulted in the filamentous phenotype characteristic of ftsZ mutants. T. acidophilum pyrF expression in an E. coli mutant lacking pyrF complemented the mutation and rescued the strain. Sequence alignments of ODCs from archaea, bacteria, and eukarya reveal five conserved regions, two of which have homology to 3-hexulose-6-phosphate synthase (HPS), suggesting a common substrate recognition and binding motif. Copyright 2000 Academic Press.

Bacterial Proteins/chemistry/genetics/metabolism↗
NASA NTRS1999

Rapid and systemic accumulation of chloroplast mRNA-binding protein transcripts after flame stimulus in tomato

It has been shown that tomato (Lycopersicon esculentum) plants respond to flame wounding and electrical stimulation by a rapid (15 min) and systemic up-regulation of proteinase inhibitor (pin) genes. To find other genes having a similar expression pattern, we used subtractive cDNA screening between flamed and control plants to select clones up-regulated by flame wounding. We report the characterization of one of them, a chloroplast mRNA-binding protein encoded by a single gene and expressed preferentially in the leaves. Systemic gene expression in response to flaming in the youngest terminal leaf exhibited three distinct phases: a rapid and transient increase (5-15 min) in transcript accumulation, a decline to basal levels (15-45 min), and then a second, more prolonged increase (60-90 min). In contrast, after a mechanical wound the rapid, transient increase (5 min) was followed by a rapid decline to basal levels but no later, prolonged accumulation. In the petiole, the initial flame-wound-evoked transient increase (15 min) was followed by a continuous decline for 3 h. The nature of the wound signal(s) causing such rapid changes in transcript abundance is discussed in relation to electrical signaling, which has recently been implicated in plant responses to wounding.

NASA Discipline Plant Biology↗
NASA NTRS1996

Activation of a Ca(2+)-dependent protein kinase involves intramolecular binding of a calmodulin-like regulatory domain

Ca(2+)-dependent protein kinases (CDPKs) are regulated by a C-terminal calmodulin-like domain (CaM-LD). The CaM-LD is connected to the kinase by a short junction sequence which contains a pseudosubstrate autoinhibitor. To understand how the CaM-LD regulates a CDPK, a recombinant CDPK (isoform CPK-1 from Arabidopsis, accession no. L14771) was made as a fusion protein in Escherichia coli. We show here that a truncated CDPK lacking a CaM-LD (e.g. mutant delta NC-26H) can be activated by exogenous calmodulin or an isolated CaM-LD (Kact approximately 2 microM). We propose that Ca2+ activation of a CDPK normally occurs through intramolecular binding of the CaM-LD to the junction. When the junction and CaM-LD are made as two separate polypeptides, the CaM-LD can bind the junction in a Ca(2+)-dependent fashion with a dissociation constant (KD) of 6 x 10(-6) M, as determined by kinetic binding analyses. When the junction and CaM-LD are tethered in a single polypeptide (e.g. in protein JC-1), their ability to engage in bimolecular binding is suppressed (e.g. the tethered CaM-LD cannot bind a separate junction). A mutation which disrupts the putative CaM-LD binding sequence (e.g. substitution LRV-1444 to DLPG) appears to block intramolecular binding, as indicated by the restored ability of a tethered CaM-LD to engage in bimolecular binding. This mutation, in the context of a full-length enzyme (mutant KJM46H), appears to block Ca2+ activation. Thus, a disruption of intramolecular binding correlates with a disruption of the Ca2+ activation mechanism. CDPKs provide the first example of a member of the calmodulin superfamily where a target binding sequence is located within the same polypeptide.

Non-NASA Center↗
NASA NTRS2004

NASA Technology Takes Center Stage

In today's fast-paced business world, there is often more information available to researchers than there is time to search through it. Data mining has become the answer to finding the proverbial "needle in a haystack," as companies must be able to quickly locate specific pieces of information from large collections of data. Perilog, a suite of data-mining tools, searches for hidden patterns in large databases to determine previously unrecognized relationships. By retrieving and organizing contextually relevant data from any sequence of terms - from genetic data to musical notes - the software can intelligently compile information about desired topics from databases.

Source record↗
NASA NTRS1985

Method and apparatus for I-V data acquisition from solar cells

A method and apparatus for logging current-voltage (I-V) characteristic d of a solar cell module (10) in two modes using a portable instrument. One mode controls the load current through a circuit (36) in 256 equal intervals while voltage is measured from open circuit to at least halfway into the knee of the curve and the other mode controls the load voltage through a circuit (34) in 256 equal intervals from the lowest voltage measurement possible (short circuit) to at least halfway into the knee of the curve, under control of a microcomputer (12). All measurements are packed by discarding each measurement that is within 0.5% of the value predicted from two previous measurements, except every ninth (9th) measurement which is retained. The remaining data is further packed into a memory block of a detachable storage medium (14) by recording the data points in sequence following a header containing data common to all points, with each point having the value of the controlled parameter recorded as the number of increments from the previous point recorded followed by the measured value. The detachable storage medium is preferably a solid state device for reliability, and is transferable to a playback terminal which unpacks the data for analysis and display.

Cole, Steven W.↗
NASA NTRS1993

[Genotoxic modification of nucleic acid bases and biological consequences of it. Review and prospects of experimental and computational investigations]

The review is presented of experimental and computational data on the influence of genotoxic modification of bases (deamination, alkylation, oxidation) on the structure and biological functioning of nucleic acids. Pathways are discussed for the influence of modification on coding properties of bases, on possible errors of nucleic acid biosynthesis, and on configurations of nucleotide mispairs. The atomic structure of nucleic acid fragments with modified bases and the role of base damages in mutagenesis and carcinogenesis are considered.

Non-NASA Center↗
NASA NTRS1991

NASTRAN GPWG tables for combined substructures

A method for computing the mass and center of gravity for basic and combined substructures stored in the NASTRAN Substructure Operating File (SOF) is described. The three step method recovers SOF data blocks for the relevant substructure, processes these data blocks using a specially developed FORTRAN routine, and generates the NASTRAN gridpoint weight generator (GPWG) table for the substructure in a PHASE2 SOF execution using a Direct Matrix Abstraction Program (DMAP) sequence. Verification data for the process is also provided.

Allen, Tom↗
NASA NTRS1990

Characterization and distribution of a maize cDNA encoding a peptide similar to the catalytic region of second messenger dependent protein kinases

Maize (Zea mays) roots respond to a variety of environmental stimuli which are perceived by a specialized group of cells, the root cap. We are studying the transduction of extracellular signals by roots, particularly the role of protein kinases. Protein phosphorylation by kinases is an important step in many eukaryotic signal transduction pathways. As a first phase of this research we have isolated a cDNA encoding a maize protein similar to fungal and animal protein kinases known to be involved in the transduction of extracellular signals. The deduced sequence of this cDNA encodes a polypeptide containing amino acids corresponding to 33 out of 34 invariant or nearly invariant sequence features characteristic of protein kinase catalytic domains. The maize cDNA gene product is more closely related to the branch of serine/threonine protein kinase catalytic domains composed of the cyclic-nucleotide- and calcium-phospholipid-dependent subfamilies than to other protein kinases. Sequence identity is 35% or more between the deduced maize polypeptide and all members of this branch. The high structural similarity strongly suggests that catalytic activity of the encoded maize protein kinase may be regulated by second messengers, like that of all members of this branch whose regulation has been characterized. Northern hybridization with the maize cDNA clone shows a single 2400 base transcript at roughly similar levels in maize coleoptiles, root meristems, and the zone of root elongation, but the transcript is less abundant in mature leaves. In situ hybridization confirms the presence of the transcript in all regions of primary maize root tissue.

NASA Program Space Biology↗