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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Crystal structure of strontium Di[bis(iminodiacetato)cobaltate(III)] pentahydrate, Sr[cis(N)-Co(Ida){sub 2}]{sub 2} {center_dot} 5H{sub 2}O

Compound Sr[cis(N)-Co(Ida){sub 2}]{sub 2} {center_dot} 5H{sub 2}O (I) is synthesized and its crystal structure is determined. The crystals are built of [Co(Ida){sub 2}]{sup -} anionic complexes, [Sr(H{sub 2}O){sub 3}]{sup 2+} hydrated cations, and crystallization water molecules. Two independent anions are located on rotation axis 2 and have close structures. A distorted octahedral coordination of Co{sup 3+} atoms is formed by two N atoms and four O atoms of two Ida{sup 2-} ligands [Co-N, 1.932(3) and 1.940(3) Angstrom-Sign ; Co-O, 1.879-1.899(3) Angstrom-Sign ]. [Sr(H{sub 2}O){sub 3}]{sup 2+} cations randomly occupy half of the positions in the vicinity of centers of inversion. In addition to three water molecules, the environment of the Sr{sup 2+} atom includes five O atoms of five Ida{sup 2-} ligands [Sr-O, 2.487(3)-2.889(5) Angstrom-Sign ]. Because of the disordering of [Sr(H{sub 2}O){sub 3}]{sup 2+} cations, the structural function of the Ida{sup 2-} ligands varies from tridentate chelate to pentadentate bridging chelate. Sr-O and hydrogen bonds connect structural elements into a three-dimensional framework. The structure of I is compared with that of a related compound Sr[CoEdta]{sub 2}{center_dot}9H{sub 2}O (II). It is shown that the formation of N-H Horizontal-Ellipsis O hydrogen bonds, which connect [Co(Ida){sub 2}]{sup -} anionic complexes in I into compact chains, is an important factor leading to the difference between packings I and II.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Quantitative principles of cis-translational control by general mRNA sequence features in eukaryotes

General translational cis-elements are present in the mRNAs of all genes and affect the recruitment, assembly, and progress of preinitiation complexes and the ribosome under many physiological states. These elements include mRNA folding, upstream open reading frames, specific nucleotides flanking the initiating AUG codon, protein coding sequence length, and codon usage. The quantitative contributions of these sequence features and how and why they coordinate to control translation rates are not well understood.

Biotechnology & Applied Microbiology↗
DOE OSTI2013

Rearrangements of 2.5 Kilobases of Noncoding DNA from the Drosophila even-skipped Locus Define Predictive Rules of Genomic cis-Regulatory Logic

Rearrangements of about 2.5 kilobases of regulatory DNA located 59 of the transcription start site of the Drosophila even skipped locus generate large-scale changes in the expression of even-skipped stripes 2, 3, and 7. The most radical effects are generated by juxtaposing the minimal stripe enhancers MSE2 and MSE3 for stripes 2 and 3 with and without small ‘‘spacer’’ segments less than 360 bp in length. We placed these fusion constructs in a targeted transformation site and obtained quantitative expression data for these transformants together with their controlling transcription factors at cellular resolution. These data demonstrated that the rearrangements can alter expression levels in stripe 2 and the 2–3 interstripe by a factor of more than 10. We reasoned that this behavior would place tight constraints on possible rules of genomic cisregulatory logic. To find these constraints, we confronted our new expression data together with previously obtained data on other constructs with a computational model. The model contained representations of thermodynamic protein–DNA interactions including steric interference and cooperative binding, short-range repression, direct repression, activation, and coactivation. The model was highly constrained by the training data, which it described within the limits of experimental error. The model, so constrained, was able to correctly predict expression patterns driven by enhancers for other Drosophila genes; even-skipped enhancers not included in the training set; stripe 2, 3, and 7 enhancers from various Drosophilid and Sepsid species; and long segments of even-skipped regulatory DNA that contain multiple enhancers. The model further demonstrated that elevated expression driven by a fusion of MSE2 and MSE3 was a consequence of the recruitment of a portion of MSE3 to become a functional component of MSE2, demonstrating that cis-regulatory ‘‘elements’’ are not elementary objects.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

The PrpF protein of Shewanella oneidensis MR-1 catalyzes the isomerization of 2-methyl- cis -aconitate during the catabolism of propionate via the AcnD-dependent 2-methylcitric acid cycle

The 2-methylcitric acid cycle (2-MCC) is a common route of propionate catabolism in microorganisms. In Salmonella enterica, the prpBCDE operon encodes most of the 2-MCC enzymes. In other organisms, e.g., Shewanella oneidensis MR-1, two genes, acnD and prpF replace prpD, which encodes 2-methylcitrate dehydratase. We showed that together, S. oneidensis AcnD and PrpF (SoAcnD, SoPrpF) compensated for the absence of PrpD in a S. enterica prpD strain. We also showed that SoAcnD had 2-methylcitrate dehydratase activity and that PrpF has aconitate isomerase activity. Here we report in vitro evidence that the product of the SoAcnD reaction is an isomer of 2-methyl-cis-aconitate (2-MCA], the product of the SePrpD reaction. We show that the SoPrpF protein isomerizes the product of the AcnD reaction into the PrpD product (2-MCA], a known substrate of the housekeeping aconitase (AcnB]. Given that SoPrpF is an isomerase, that SoAcnD is a dehydratase, and the results from in vivo and in vitro experiments reported here, it is likely that 4-methylaconitate is the product of the AcnD enzyme. Results from in vivo studies using a S. enterica prpD strain show that SoPrpF variants with substitutions of residues K73 or C107 failed to support growth with propionate as the sole source of carbon and energy. High-resolution (1.22 Å) three-dimensional crystal structures of PrpF K73E in complex with trans-aconitate or malonate provide insights into the mechanism of catalysis of the wild-type protein.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Characterization of Multiple Trichloroethene, cis-Dichloroethene and 1,1-Dichloroethene Degrading Propanotrophic Communities

Aerobic cometabolism offers a viable strategy for the remediation of chlorinated solvent plumes at oxic sites where anaerobic approaches are limited. In this study, propane-enriched mixed cultures (derived from agricultural soils and an impacted site sediment) which previously degraded 1,4-dioxane, were evaluated for their capacity to also degrade trichloroethene (TCE), cis-1,2-dichloroethene (cDCE), and 1,1-dichloroethene (1,1-DCE) over successive transfers. Sustained biodegradation of TCE and cDCE was observed across multiple enrichments, and cultures enriched on one compound generally degraded the other. In contrast, 1,1-DCE biodegradation was restricted to a subset of cultures and removal times increased over transfers. Further, 1,1-DCE removal was absent at elevated concentrations, both trends consistent with inhibitory or toxic effects. Whole genome sequencing analyses revealed pronounced substrate-dependent selection of microbial communities, with cDCE-degrading cultures being dominated by Mycobacterium and Mycolicibacterium, whereas TCE-degrading cultures were dominated by Rhodococcus. Rhodococcus metagenome-assembled genomes (MAGs) in the TCE degrading cultures classified as R. opacus or R. wratislaviensis. 1,1-DCE degrading cultures were dominated by Pseudonocardia, although the associated MAGs contained a truncated propane monooxygenase alpha subunit. Functional gene analysis identified both group 5 (prmABCD) and putative group 6 propane monooxygenases. The following KBase narratives contain the quality controlled reads, MAGs (fasta assemblies) and the prokka annotations for each assembly TCE Site 1A and B Propanotrophic MAGs (https://narrative.kbase.us/narrative/254918) TCE Soil 2A and B Propanotrophic MAGs (https://narrative.kbase.us/narrative/254919) TCE Soil T3 A and B Propanotrophic MAGs (https://narrative.kbase.us/narrative/254920) TCE Soil T4 A and B Propanotrophic MAGs (https://narrative.kbase.us/narrative/254921) cDCE Site 1A 1B Propanotrophic MAGs (https://narrative.kbase.us/narrative/254915) cDCE Soils T2 A and B Propanotrophic MAGs (https://narrative.kbase.us/narrative/254927) cDCE Soil T3 A and B Propanotrophic MAGs (https://narrative.kbase.us/narrative/254928) cDCE Soil 4A and B Propanotrophic MAGs (https://narrative.kbase.us/narrative/254942) 1,1-DCE T2 T3 Propanotrophic MAGs (https://narrative.kbase.us/narrative/254903)

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1972

Microwave spectrum of cis-glyoxal.

The rotational spectrum of glyoxal has been investigated in the region from 18.0 to 40.0 GHz. Only B-type transitions were observed. Both Q-branch and R-branch assignments have been made for the ground state, and the Q-branch assignment has been made for the first excited state of the internal rotational mode. From relative intensity measurements of vibrational excited states, the torsional vibration is found to have a frequency of 114 plus or minus 8 per cm. From a consideration of the rotational constants, it is concluded that the isomer giving rise to the microwave spectrum is the planar cis form and not the gauche isomer. The dipole moment was determined to be 4.8 plus or minus 0.2 D.

Durig, J. R.↗
NASA NTRS1984

PDSS/IMC CIS user's guide

The Spacelab Payload Development Support System PDSS Image Motion Compensator (IMC) computer interface simulation (CIS) user's manual is given. The software provides a real time interface simulation for the following IMC subsystems: the Dry Rotor Reference Unit, the Advanced Star/Target Reference Optical sensor, the Ultra Violet imaging telescope, the Wisconson Ultraviolet Photopolarimetry Experiment, the Cruciform Power distributor, and the Spacelab Experiment Computer Operating System.

Source record↗
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 NTRS1991

Analytic gradients for coupled-cluster energies that include noniterative connected triple excitations - Application to cis- and trans-HONO

An efficient formulation of the analytic energy gradient for the single and double excitation coupled-cluster method that includes a perturbational estimate of the effects of connected triple excitations is presented. The formulation has a small computational cost, and the algebraic manipulations may be applied generally to the analytic gradient of Moller-Plesset perturbation theory energies. The new formulation has been implemented in an efficient set of programs that utilize highly vectorized algorithms and has been used to investigate the equilibrium structures, harmonic vibrational frequencies, IR intensities, and energy separation of cis- and trans-HONO.

Lee, Timothy J.↗
NASA NTRS2003

Conservation of Endo16 expression in sea urchins despite evolutionary divergence in both cis and trans-acting components of transcriptional regulation

Evolutionary changes in transcriptional regulation undoubtedly play an important role in creating morphological diversity. However, there is little information about the evolutionary dynamics of cis-regulatory sequences. This study examines the functional consequence of evolutionary changes in the Endo16 promoter of sea urchins. The Endo16 gene encodes a large extracellular protein that is expressed in the endoderm and may play a role in cell adhesion. Its promoter has been characterized in exceptional detail in the purple sea urchin, Strongylocentrotus purpuratus. We have characterized the structure and function of the Endo16 promoter from a second sea urchin species, Lytechinus variegatus. The Endo16 promoter sequences have evolved in a strongly mosaic manner since these species diverged approximately 35 million years ago: the most proximal region (module A) is conserved, but the remaining modules (B-G) are unalignable. Despite extensive divergence in promoter sequences, the pattern of Endo16 transcription is largely conserved during embryonic and larval development. Transient expression assays demonstrate that 2.2 kb of upstream sequence in either species is sufficient to drive GFP reporter expression that correctly mimics this pattern of Endo16 transcription. Reciprocal cross-species transient expression assays imply that changes have also evolved in the set of transcription factors that interact with the Endo16 promoter. Taken together, these results suggest that stabilizing selection on the transcriptional output may have operated to maintain a similar pattern of Endo16 expression in S. purpuratus and L. variegatus, despite dramatic divergence in promoter sequence and mechanisms of transcriptional regulation.

NASA Discipline Evolutionary Biology↗
NASA NTRS2001

Rapid evolution of cis-regulatory sequences via local point mutations

Although the evolution of protein-coding sequences within genomes is well understood, the same cannot be said of the cis-regulatory regions that control transcription. Yet, changes in gene expression are likely to constitute an important component of phenotypic evolution. We simulated the evolution of new transcription factor binding sites via local point mutations. The results indicate that new binding sites appear and become fixed within populations on microevolutionary timescales under an assumption of neutral evolution. Even combinations of two new binding sites evolve very quickly. We predict that local point mutations continually generate considerable genetic variation that is capable of altering gene expression.

Non-NASA Center↗
NASA NTRS2015

Germinating the 2050 Cis-Lunar Econosphere

In early 2013, Marshall Space Flight Center's upper management chartered a diverse team for a six-week 'sprint' to speculate (in a disciplined manner) and paint (with broad brush strokes) a picture of how earth, space, and public/private entities might be operating and relating to each other... in the year 2100. Two 12-person groups of civil servants, one with members having 15 years or less of NASA experience and the other with more senior members, worked independently and then compared and integrated their conclusions. In 2014, the 'Space 2100' team, with some new team members and different group boundaries, ran a longer sprint to a) develop more detailed estimates of the operations and economics of space activities in the vicinity of the Earth and Moon in the 2050 time frame, b) identify evolutionary paths, barriers, and opportunities, and c) suggest actions and philosophies to enable and invigorate progress towards the vision. This paper explores Space 2100's first two sprints and their projections of NASA's role in what will likely be a highly networked, international space industry and cis-lunar infrastructure.

Scott, David W.↗
NASA NTRS2015

Germinating the 2050 Cis-Lunar Econosphere

In early 2013, the Marshall Space Flight Center (MSFC) Director and MSFC's Office of Strategic Analysis and Communications (OSAC) chartered a diverse team for a six-week "sprint" to speculate (in a disciplined manner) and paint (with broad brush strokes) a picture of how earth, space, and public/private entities might be operating and relating to each other...in the year 2100. Two 12-person groups of civil servants, one with members having 15 years or less of NASA experience and the other with more senior members, worked independently and then compared and integrated their conclusions. In 2014, the "Space 2100" team, with some new team members and different group boundaries, ran a longer sprint to a) develop more detailed estimates of the operations and economics of space activities in the vicinity of the Earth and Moon in the 2050 time frame, b) identify evolutionary steps and viable paths needed to make that a reality, and c) recommend actions to enable and invigorate those steps. This paper explores Space 2100's first two sprints and their projections of NASA's role in what will likely be a highly networked international space industry and cis-lunar infrastructure.

Scott, David W.↗
NASA NTRSDate not supplied

Parametric Cost Analysis of Refueling Options in Cis-Lunar Space

Over the next several years NASA intends to develop and maintain a sustained human presence in cis-lunar space and on the surface of the moon. The sustained lunar presence will then serve as a stepping stone to human Mars missions. To propel the spacecraft taking humans and cargo to and from the lunar surface and to and from Mars will require on the order of hundreds of tons of propellant. Expendable, one-time use refueling elements maybe more cost effective for smaller campaigns, but as the propellant requirement grows, so does the cost benefit of reusable systems. This paper will analyze the cost of several different architectures for delivering propellant to cislunar space to determine the conditions in which each architecture is likely to be more cost effective. The first architecture relies on expendable elements for propellant delivery while the second one reuses every element including launch vehicle stages. In addition to these two basic approaches, trades will analyze alterations to the architectures such as mission design, level of thermal control, and the incorporation of buses,tugs, and depots, each with different propellants, sizes, and reusability assumptions.

Paul D Friz↗
NASA NTRSDate not supplied

NASA Development of Hardware for Life Support Systems in Cis Lunar and Surface Habitats

Sustained human presence requires the ability to survive with a minimal Earth supply chain and minimal communications from Earth. NASA is working on mission platforms to aggregate ECLS functions into a cis lunar and lunar surface architectures to demonstrate Mars forward capabilities and reduce the risk for human missions to Mars. This means the Environmental Control and Life Support (ECLS) technologies in the vehicle architecture will need to recover air and water from human and consumable waste products to support humans for short and long duration missions. NASA is developing ECLS technologies for Air Revitalization, Water Recovery and Management, Waste Management and Environmental Monitoring. Implementation of these technologies on microgravity and partial gravity platforms will collect component and system data on manned missions to increase the reliability needed for mission beyond Low Earth Orbit.

Imelda C. Stambaugh↗