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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 1,027 records · Page 57
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Influence of microgravity on root-cap regeneration and the structure of columella cells in Zea mays

We launched imbibed seeds and seedlings of Zea mays into outer space aboard the space shuttle Columbia to determine the influence of microgravity on 1) root-cap regeneration, and 2) the distribution of amyloplasts and endoplasmic reticulum (ER) in the putative statocytes (i.e., columella cells) of roots. Decapped roots grown on Earth completely regenerated their caps within 4.8 days after decapping, while those grown in microgravity did not regenerate caps. In Earth-grown seedlings, the ER was localized primarily along the periphery of columella cells, and amyloplasts sedimented in response to gravity to the lower sides of the cells. Seeds germinated on Earth and subsequently launched into outer space had a distribution of ER in columella cells similar to that of Earth-grown controls, but amyloplasts were distributed throughout the cells. Seeds germinated in outer space were characterized by the presence of spherical and ellipsoidal masses of ER and randomly distributed amyloplasts in their columella cells. These results indicate that 1) gravity is necessary for regeneration of the root cap, 2) columella cells can maintain their characteristic distribution of ER in microgravity only if they are exposed previously to gravity, and 3) gravity is necessary to distribute the ER in columella cells of this cultivar of Z. mays.

NASA Discipline Number 00-00↗
NASA NTRS1998

Changing patterns of localization of the tobacco mosaic virus movement protein and replicase to the endoplasmic reticulum and microtubules during infection

Tobacco mosaic virus (TMV) derivatives that encode movement protein (MP) as a fusion to the green fluorescent protein (MP:GFP) were used in combination with antibody staining to identify host cell components to which MP and replicase accumulate in cells of infected Nicotiana benthamiana leaves and in infected BY-2 protoplasts. MP:GFP and replicase colocalized to the endoplasmic reticulum (ER; especially the cortical ER) and were present in large, irregularly shaped, ER-derived structures that may represent "viral factories." The ER-derived structures required an intact cytoskeleton, and microtubules appeared to redistribute MP:GFP from these sites during late stages of infection. In leaves, MP:GFP accumulated in plasmodesmata, whereas in protoplasts, the MP:GFP was targeted to distinct, punctate sites near the plasma membrane. Treating protoplasts with cytochalasin D and brefeldin A at the time of inoculation prevented the accumulation of MP:GFP at these sites. It is proposed that the punctate sites anchor the cortical ER to plasma membrane and are related to sites at which plasmodesmata form in walled cells. Hairlike structures containing MP:GFP appeared on the surface of some of the infected protoplasts and are reminiscent of similar structures induced by other plant viruses. We present a model that postulates the role of the ER and cytoskeleton in targeting the MP and viral ribonucleoprotein from sites of virus synthesis to the plasmodesmata through which infection is spread.

NASA Discipline Plant Biology↗
NASA NTRS2013

Range-Specific High-resolution Mesoscale Model Setup

This report summarizes the findings from an AMU task to determine the best model configuration for operational use at the ER and WFF to best predict winds, precipitation, and temperature. The AMU ran test cases in the warm and cool seasons at the ER and for the spring and fall seasons at WFF. For both the ER and WFF, the ARW core outperformed the NMM core. Results for the ER indicate that the Lin microphysical scheme and the YSU PBL scheme is the optimal model configuration for the ER. It consistently produced the best surface and upper air forecasts, while performing fairly well for the precipitation forecasts. Both the Ferrier and Lin microphysical schemes in combination with the YSU PBL scheme performed well for WFF in the spring and fall seasons. The AMU has been tasked with a follow-on modeling effort to recommended local DA and numerical forecast model design optimized for both the ER and WFF to support space launch activities. The AMU will determine the best software and type of assimilation to use, as well as determine the best grid resolution for the initialization based on spatial and temporal availability of data and the wall clock run-time of the initialization. The AMU will transition from the WRF EMS to NU-WRF, a NASA-specific version of the WRF that takes advantage of unique NASA software and datasets. 37

Watson, Leela R.↗
NASA NTRS2015

Correlation of Electrical Resistance to CMC Stress-Strain and Fracture Behavior Under High Heat-Flux Thermal and Stress Gradients

Because SiCSiC ceramic matrix composites (CMCs) are under consideration for use as turbine engine hot-section components in extreme environments, it becomes necessary to investigate their performance and damage morphologies under complex loading and environmental conditions. Monitoring of electrical resistance (ER) has been shown as an effective tool for detecting damage accumulation of woven melt-infiltrated SiCSiC CMCs. However, ER change under complicated thermo-mechanical loading is not well understood. In this study a systematic approach is taken to determine the capabilities of ER as a relevant non-destructive evaluation technique for high heat-flux testing, including thermal gradients and localized stress concentrations. Room temperature and high temperature, laser-based tensile tests were conducted in which stress-dependent damage locations were determined using modal acoustic emission (AE) monitoring and compared to full-field strain mapping using digital image correlation (DIC). This information is then compared with the results of in-situ ER monitoring, post-test ER inspection and fractography in order to correlate ER response to convoluted loading conditions and damage evolution.

electrical resistance↗
DOE OSTI2020

A temporal hierarchy underpins the transcription factor–DNA interactome of the maize UPR

Adverse environmental conditions reduce crop productivity and often increase the load of unfolded or misfolded proteins in the endoplasmic reticulum (ER). This potentially lethal condition, known as ER stress, is buffered by the unfolded protein response (UPR), a set of signaling pathways designed to either recover ER functionality or ignite programmed cell death. Despite the biological significance of the UPR to the life of the organism, the regulatory transcriptional landscape underpinning ER stress management is largely unmapped, especially in crops. To fill this significant knowledge gap, we performed a large–scale systems–level analysis of the protein–DNA interaction (PDI) network in maize (Zea mays). Using 23 promoter fragments of six UPR marker genes in a high–throughput enhanced yeast one–hybrid assay, we identified a highly interconnected network of 262 transcription factors (TFs) associated with significant biological traits and 831 PDIs underlying the UPR. We established a temporal hierarchy of TF binding to gene promoters within the same family as well as across different families of TFs. Cistrome analysis revealed the dynamic activities of a variety of cis–regulatory elements (CREs) in ER stress–responsive gene promoters. By integrating the cistrome results into a TF network analysis, we mapped a subnetwork of TFs associated with a CRE that may contribute to UPR management. Lastly, we validated the role of a predicted network hub gene using the Arabidopsis system. The PDIs, TF networks, and CREs identified in our work are foundational resources for understanding transcription–regulatory mechanisms in the stress responses and crop improvement.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Materials Data on ErGaCo by Materials Project

ErCoGa crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Er is bonded in a 11-coordinate geometry to five equivalent Co and six equivalent Ga atoms. There are a spread of Er–Co bond distances ranging from 2.83–2.89 Å. There are a spread of Er–Ga bond distances ranging from 3.01–3.13 Å. Co is bonded in a 9-coordinate geometry to five equivalent Er and four equivalent Ga atoms. There are a spread of Co–Ga bond distances ranging from 2.52–2.58 Å. Ga is bonded in a 12-coordinate geometry to six equivalent Er and four equivalent Co atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErCd2Cu by Materials Project

ErCuCd2 is Bergman Structure: Mg32(Al,Zn)49 Bergman-like structured and crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Er is bonded in a 12-coordinate geometry to four equivalent Cu and eight equivalent Cd atoms. There are two shorter (2.99 Å) and two longer (3.50 Å) Er–Cu bond lengths. There are a spread of Er–Cd bond distances ranging from 3.11–3.21 Å. Cu is bonded in a 12-coordinate geometry to four equivalent Er and eight equivalent Cd atoms. There are a spread of Cu–Cd bond distances ranging from 2.87–3.24 Å. Cd is bonded in a 11-coordinate geometry to four equivalent Er, four equivalent Cu, and three equivalent Cd atoms. There are one shorter (2.90 Å) and two longer (3.06 Å) Cd–Cd bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErCoSn by Materials Project

ErCoSn crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Er is bonded in a 9-coordinate geometry to four equivalent Co and six equivalent Sn atoms. There are a spread of Er–Co bond distances ranging from 2.92–3.04 Å. There are a spread of Er–Sn bond distances ranging from 3.10–3.24 Å. Co is bonded in a 8-coordinate geometry to four equivalent Er and four equivalent Sn atoms. There are two shorter (2.61 Å) and two longer (2.63 Å) Co–Sn bond lengths. Sn is bonded in a 10-coordinate geometry to six equivalent Er and four equivalent Co atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErCdCu4 by Materials Project

ErCu4Cd is Hexagonal Laves-derived structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Er is bonded in a 12-coordinate geometry to twelve equivalent Cu and four equivalent Cd atoms. All Er–Cu bond lengths are 2.98 Å. All Er–Cd bond lengths are 3.11 Å. Cu is bonded to three equivalent Er, six equivalent Cu, and three equivalent Cd atoms to form a mixture of corner, edge, and face-sharing CuEr3Cd3Cu6 cuboctahedra. There are three shorter (2.53 Å) and three longer (2.55 Å) Cu–Cu bond lengths. All Cu–Cd bond lengths are 2.98 Å. Cd is bonded in a 4-coordinate geometry to four equivalent Er and twelve equivalent Cu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErGeAu by Materials Project

ErAuGe crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Er is bonded in a 8-coordinate geometry to six equivalent Au and five equivalent Ge atoms. There are three shorter (3.00 Å) and three longer (3.54 Å) Er–Au bond lengths. There are a spread of Er–Ge bond distances ranging from 2.86–3.09 Å. Au is bonded in a 6-coordinate geometry to six equivalent Er, two equivalent Au, and three equivalent Ge atoms. Both Au–Au bond lengths are 3.00 Å. All Au–Ge bond lengths are 2.98 Å. Ge is bonded to five equivalent Er and three equivalent Au atoms to form a mixture of edge and corner-sharing GeEr5Au3 hexagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er2InPd2 by Materials Project

Er2Pd2In crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Er is bonded in a 6-coordinate geometry to six equivalent Pd and four equivalent In atoms. There are two shorter (2.84 Å) and four longer (2.98 Å) Er–Pd bond lengths. All Er–In bond lengths are 3.39 Å. Pd is bonded in a 9-coordinate geometry to six equivalent Er, one Pd, and two equivalent In atoms. The Pd–Pd bond length is 2.79 Å. Both Pd–In bond lengths are 3.03 Å. In is bonded to eight equivalent Er and four equivalent Pd atoms to form a mixture of face and corner-sharing InEr8Pd4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErAsPd by Materials Project

ErPdAs crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Er is bonded in a 11-coordinate geometry to six equivalent Pd and five equivalent As atoms. There are a spread of Er–Pd bond distances ranging from 3.05–3.40 Å. There are a spread of Er–As bond distances ranging from 2.89–2.98 Å. Pd is bonded to six equivalent Er, two equivalent Pd, and four equivalent As atoms to form a mixture of distorted edge, face, and corner-sharing PdEr6As4Pd2 cuboctahedra. Both Pd–Pd bond lengths are 3.03 Å. There are a spread of Pd–As bond distances ranging from 2.62–2.81 Å. As is bonded in a 9-coordinate geometry to five equivalent Er and four equivalent Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErSnAu by Materials Project

ErAuSn crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Er is bonded in a 12-coordinate geometry to six equivalent Au and six equivalent Sn atoms. There are three shorter (2.98 Å) and three longer (3.67 Å) Er–Au bond lengths. There are three shorter (3.20 Å) and three longer (3.38 Å) Er–Sn bond lengths. Au is bonded in a 10-coordinate geometry to six equivalent Er and four equivalent Sn atoms. There are three shorter (2.82 Å) and one longer (2.93 Å) Au–Sn bond lengths. Sn is bonded in a 10-coordinate geometry to six equivalent Er and four equivalent Au atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErGePt by Materials Project

ErPtGe crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Er is bonded in a 12-coordinate geometry to six equivalent Pt and six equivalent Ge atoms. There are a spread of Er–Pt bond distances ranging from 2.99–3.24 Å. There are a spread of Er–Ge bond distances ranging from 3.01–3.22 Å. Pt is bonded in a 10-coordinate geometry to six equivalent Er and four equivalent Ge atoms. There are a spread of Pt–Ge bond distances ranging from 2.55–2.77 Å. Ge is bonded in a 10-coordinate geometry to six equivalent Er and four equivalent Pt atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErAl7Au3 by Materials Project

ErAu3Al7 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. Er is bonded in a 6-coordinate geometry to six equivalent Au and twelve equivalent Al atoms. All Er–Au bond lengths are 3.25 Å. There are six shorter (3.32 Å) and six longer (3.37 Å) Er–Al bond lengths. Au is bonded in a 9-coordinate geometry to two equivalent Er and seven Al atoms. There are a spread of Au–Al bond distances ranging from 2.59–2.67 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded in a distorted trigonal planar geometry to two equivalent Er and three equivalent Au atoms. In the second Al site, Al is bonded in a trigonal planar geometry to three equivalent Au atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErCuPb by Materials Project

ErCuPb crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Er is bonded in a 12-coordinate geometry to three equivalent Cu and six equivalent Pb atoms. All Er–Cu bond lengths are 2.93 Å. There are three shorter (3.15 Å) and three longer (3.30 Å) Er–Pb bond lengths. Cu is bonded in a 7-coordinate geometry to three equivalent Er and four equivalent Pb atoms. There are three shorter (2.75 Å) and one longer (2.93 Å) Cu–Pb bond lengths. Pb is bonded in a 10-coordinate geometry to six equivalent Er and four equivalent Cu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er3(AlNi3)2 by Materials Project

Er3(Ni3Al)2 crystallizes in the cubic Im-3m space group. The structure is three-dimensional. Er is bonded in a 12-coordinate geometry to eight equivalent Ni and four equivalent Al atoms. There are four shorter (2.76 Å) and four longer (2.99 Å) Er–Ni bond lengths. All Er–Al bond lengths are 3.15 Å. Ni is bonded in a 12-coordinate geometry to four equivalent Er, four equivalent Ni, and two equivalent Al atoms. All Ni–Ni bond lengths are 2.56 Å. Both Ni–Al bond lengths are 2.46 Å. Al is bonded in a distorted hexagonal planar geometry to six equivalent Er and six equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErMnSi by Materials Project

ErMnSi crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Er is bonded in a 5-coordinate geometry to six equivalent Mn and five equivalent Si atoms. There are a spread of Er–Mn bond distances ranging from 2.96–3.29 Å. There are a spread of Er–Si bond distances ranging from 2.90–2.95 Å. Mn is bonded in a 4-coordinate geometry to six equivalent Er and four equivalent Si atoms. There are a spread of Mn–Si bond distances ranging from 2.46–2.69 Å. Si is bonded in a 9-coordinate geometry to five equivalent Er and four equivalent Mn atoms.

36 MATERIALS SCIENCE↗