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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

The Role of Sexual Dimorphism and Tissue Selection in Ecotoxicological Studies Using the Riparian Spider Tetragnatha elongata

Tetragnathid spiders (Tetragnatha spp.) found in riparian habitats have recently been used as bioindicators of sediment contamination and insect-mediated contaminant flux. We investigated whether sexual dimorphism (size and behavior) influenced the female:male ratio in composite samples, stable isotope ratios (carbon [δ{sup 13}C], nitrogen [δ{sup 15}N]), and Hg concentrations in the southern United States. Additionally, we explored whether biomass for contaminant analysis could be preserved by using the legs of tetragnathids as a surrogate for whole-body δ{sup 13}C and δ{sup 15}N signatures. We found that female tetragnathids were significantly larger than male spiders and represented a larger proportion of spiders collected at all sites. However, despite the difference in size between sexes, no differences in growth dynamics, isotopic signatures (δ{sup 13}C and δ{sup 15}N), or mercury concentrations were observed. It was determined that the leg of a tetragnathid can accurately represent the stable isotope signature of an entire spider.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Substrate induced modulation of electronic, magnetic and chemical properties of MoSe{sub 2} monolayer

Monolayer of MoSe{sub 2}, having a typical direct band gap of ∼1.5 eV, is a promising material for optoelectronic and solar cell applications. When this 2D semiconductor is supported on transition metal substrates, such as Ni(111) and Cu(111), its electronic structure gets modulated. First principles density functional investigation shows the appearance of de-localized mid-gap states in the density of states. The work function of the semiconductor overlayer gets modified considerably, indicating n-type doping caused by the metal contacts. The charge transfer across the metal-semiconductor junction also significantly enhances the chemical reactivity of the MoSe{sub 2} overlayer, as observed by Hydrogen absorption. Furthermore, for Ni contact, there is a signature of induced magnetism in MoSe{sub 2} monolayer.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Topological crystalline magnets: Symmetry-protected topological phases of fermions

Here, we introduce a novel class of interaction-enabled topological crystalline insulators in two- and three-dimensional electronic systems, which we call “topological crystalline magnet.” It is protected by the product of the time-reversal symmetry T and a mirror symmetry or a rotation symmetry R . A topological crystalline magnet exhibits two intriguing features: (i) it cannot be adiabatically connected to any Slater insulator and (ii) the edge state is robust against coupling electrons to the edge. These features are protected by the anomalous symmetry transformation property ( RT ) 2 = -1 of the edge state. Finally, an anisotropic response to the external magnetic field can be an experimental signature.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Spectroanalysis in native gels (SING): rapid spectral analysis of pigmented thylakoid membrane complexes separated by CN-PAGE

Photosynthetic organisms rapidly adjust the capture, transfer and utilization of light energy to optimize the efficiency of photosynthesis and avoid photodamage. These adjustments involve fine-tuning of expression levels and mutual interactions among electron/proton transfer components and their associated light-harvesting antenna. Detailed studies of these interactions and their dynamics have been hindered by the low throughput and resolution of currently available research tools, which involve laborious isolation, separation and characterization steps. To address these issues, we developed an approach that measured multiple spectroscopic properties of thylakoid preparations directly in native polyacrylamide gel electrophoresis gels, enabling unprecedented resolution of photosynthetic complexes, both in terms of the spectroscopic and functional details, as well as the ability to distinguish separate complexes and thus test their functional connections. As a demonstration, we explore the thylakoid membrane components of Chlamydomonas reinhardtii acclimated to high and low light, using a combination of room temperature absorption and 77K fluorescence emission to generate a multi-dimensional molecular and spectroscopic map of the photosynthetic apparatus. We show that low-light-acclimated cells accumulate a photosystem I-containing megacomplex that is absent in high-light-acclimated cells and contains distinct LhcII proteins that can be distinguished based on their spectral signatures.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Emergent orbital magnetization in Kitaev quantum magnets

Unambiguous identification of the Kitaev quantum spin liquid (QSL) in materials remains a huge challenge despite many encouraging signs from various measurements. To facilitate the experimental detection of the Kiteav QSL, here we propose to use remnant charge response in Mott insulators hosting QSL to identify the key signatures of QSL. We predict an emergent orbital magnetization in a Kitaev system in an external magnetic field. The direction of the orbital magnetization can be flipped by rotating the external magnetic field in the honeycomb plane. The orbital magnetization is demonstrated explicitly through a detailed microscopic analysis of the multiorbital Hubbard-Kanamori Hamiltonian and also supported by a phenomenological picture. We first derive the localized electrical loop current operator in terms of the spin degrees of freedom. Thereafter, utilizing the Majorana representation, we estimate the loop currents in the ground state of the chiral Kitaev QSL state, and obtain the consequent current textures, which are responsible for the emergent orbital magnetization. Finally, we discuss the possible experimental techniques to visualize the orbital magnetization which can be considered as the signatures of the underlying excitations.

36 MATERIALS SCIENCE↗
NASA NTRS2018

The Mars Reconnaissance Orbiter Mission: 2018 Status

The Mars Reconnaissance Orbiter (MRO) continues its dual-mode mission of scientific exploration and programmatic support. Now in its 13th year of flight (and its 12th year in its low-altitude, sun-synchronous orbit around Mars), the spacecraft continues in its normal flight mode and its science instruments continue to acquire a treasure trove of data which is being used to study the Martian environment (surface, sub-surface, and atmosphere). To date (July 2018), more than 333 TB of scientific data have been returned to Earth. Building onto the 2017 IAC paper: “The Mars Reconnaissance Orbiter Mission: Continuing a Record of Exploration from Mars Orbit,” [1] this paper provides a 2018 status update on the MRO Mission. A signature event since the 2017 writing is the onset and evolution of a planet-encircling dust event (PEDE), the first such event since 2007. Additional recent science highlights for MRO include the discovery of mid-latitude ice cliffs, polar cap characterization, daily global mapping of the 2018 PEDE dust activity and the atmospheric thermal response, further characterization of the tantalizing recurring slope lineae (RSL), and continued detection of surface changes. Programmatically, UHF relay support for the Mars Science Laboratory (MSL) rover Curiosity and the Mars Exploration Rover (MER) rover Opportunity continues at a pace that provides the engineers and scientists operating those surface vehicles timely information to support their mission planning and science analysis. Most of the landing site characterization requests for the NASA Mars 2020 rover and the ESA ExoMars Rover/Surface Platform (RSP) missions have been completed, with final acquisitions delayed due to the obscuring dust haze from the current PEDE. In parallel, the flight team has faced new engineering challenges as the spacecraft has aged. The team has developed and is implementing actions that are aimed at stretching spacecraft battery life. A new all-stellar capability using the spacecraft’s star trackers now allows for normal spacecraft operations without IMUs. In addition to its current relay duties, MRO will be synchronized to provide critical communications support for the InSight Entry, Descent, and Landing (EDL) event on November 26, 2018, and will be readied to support InSight’s critical commissioning phase with UHF relay support and environmental characterization. A new split-pass relay capability has been developed which will allow MRO to relay with two surface vehicles in “close proximity” on the same overflight, i.e. the InSight lander and the Curiosity rover. Extended for another year of operations by NASA, this paper will highlight recent scientific progress and describe actions that will extend MRO’s life well into the 2020’s as a key element of the Mars Exploration Program.

Zurek, Richard W.↗
DOE OSTI2019

Genetic Analysis of the Full-Length gag Gene from the Earliest Korean Subclade B of HIV-1: An Outbreak among Korean Hemophiliacs

We determined the earliest full-length HIV-1 gag gene sequences in 110 patients with HIV-1, including 20 hemophiliacs (HPs) and 90 local controls (LCs). The gag gene from stored sera was amplified using RT-PCR, and was subjected to direct sequencing. Phylogenetic analysis indicated that 94 and 16 sequences belonged to the Korean subclade of HIV-1 subtype B (KSB) and subtype B, respectively. A total of 12 signature pattern amino acids were found within the KSB, distinct from the worldwide consensus of subtype B. Within the KSB, the gag gene sequences from donors O and P and those from the 20 HPs comprised two subclusters. In particular, sequences from donor O strongly clustered with those of eight HPs. Moreover, signature pattern analysis indicated that 14 signature nucleotides were shared between the HPs and LCs within KSB (p < 0.01). Among the 14 nucleotides, positions 9 and 5 belonged to clusters O and P, respectively. In conclusion, signature pattern analysis for the gag gene revealed 12 signature pattern residues within the KSB and also confirmed the previous conclusion that the 20 HPs were infected with viruses due to incompletely inactivated clotting factor IX. This study is the first genetic analysis of the HIV-1 gag gene in Korea.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS2017

Preliminary Design of the Continuous ADRs for the Primordial Inflation Explorer (PIXIE)

PIXIE is a recently proposed middle-class explorer mission designed to produce full-sky maps of polarization in the Cosmic Microwave Background (CMB). PIXIEs challenging science goals require not only measuring the extremely faint b-modes of the CMB, but distinguishing between true CMB signatures and 1) polarized light reflecting off local dust, and 2) signals arising from within the instrument. PIXIEs detectors will operate at 100 mK in order to achieve the required sensitivity. Instrument errors will be minimized in part by operating the telescope and optics at an average temperature close to that of the CMB (2.72 K) and systematically varying the temperature of various components by a small amount (10-20 mK). Signals appearing at the frequency of those variations can then be subtracted out. For this to be successful at the level required, it is necessary for the pattern of temperatures to be stable over very long time frames. Consequently, cooling of the detectors and telescope will be done using two 3-stage ADR assemblies that will produce continuous cooling, one at 100 mK and the other at approximately 2.65 K. The latter will act as the heat sink for 100 mK ADR and establish a base temperature from which the telescope and optics will be regulated. Its heat sink is a 4.5 K cryocooler. The design and operation of the ADRs will be discussed.

magnetic refrigeration↗
NASA NTRS2019

Impacts of Space Weather on Climate and Habitability of Terrestrial Type Exoplanets

The current progress in the detection of terrestrial type exoplanets has opened a new avenue in the characterization of exoplanetary atmospheres and in the search for biosignatures of life with the upcoming ground-based and space missions. To specify the conditions favorable for the origin, development and sustainment of life as we know it in other worlds, we need to understand the nature of astrospheric, atmospheric and surface environments of exoplanets in habitable zones around G-K-M dwarfs including our young Sun. Global environment is formed by propagated disturbances from the planet-hosting stars in the form of stellar flares, coronal mass ejections, energetic particles, and winds collectively known as astrospheric space weather. Its characterization will help in understanding how an exoplanetary ecosystem interacts with its host star, as well as in the specification of the physical, chemical and biochemical conditions that can create favorable and/or detrimental conditions for planetary climate and habitability along with evolution of planetary internal dynamics over geological timescales. A key linkage of (astro) physical, chemical, and geological processes can only be understood in the framework of interdisciplinary studies with the incorporation of progress in heliophysics, astrophysics, planetary and Earth sciences. The assessment of the impacts of host stars on the climate and habitability of terrestrial (exo)planets will significantly expand the current definition of the habitable zone to the biogenic zone and provide new observational strategies for searching for signatures of life. The major goal of this paper is to describe and discuss the current status and recent progress in this interdisciplinary field and to provide a new roadmap for the future development of the emerging field of exoplanetary science and astrobiology.

astrophysics↗
DOE OSTI2017

Where There’s Smoke, There’s Science

Cloaking urban areas and wildfire zones, tiny smoke particles suspended in the atmosphere have a sizeable effect on our climate. But the exact effect of many of these aerosols-such as how much sunlight they absorb, thus warming Earth, or reflecting back to space and so cooling Earth-is very uncertain.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Evolutionary Diversification of Host-Targeted Bartonella Effectors Proteins Derived from a Conserved FicTA Toxin-Antitoxin Module

Proteins containing a FIC domain catalyze AMPylation and other post-translational modifications (PTMs). In bacteria, they are typically part of FicTA toxin-antitoxin modules that control conserved biochemical processes such as topoisomerase activity, but they have also repeatedly diversified into host-targeted virulence factors. Among these, Bartonella effector proteins (Beps) comprise a particularly diverse ensemble of FIC domains that subvert various host cellular functions. However, no comprehensive comparative analysis has been performed to infer molecular mechanisms underlying the biochemical and functional diversification of FIC domains in the vast Bep family. Here, we used X-ray crystallography, structural modelling, and phylogenetic analyses to unravel the expansion and diversification of Bep repertoires that evolved in parallel in three Bartonella lineages from a single ancestral FicTA toxin-antitoxin module. Our analysis is based on 99 non-redundant Bep sequences and nine crystal structures. Inferred from the conservation of the FIC signature motif that comprises the catalytic histidine and residues involved in substrate binding, about half of them represent AMP transferases. A quarter of Beps show a glutamate in a strategic position in the putative substrate binding pocket that would interfere with triphosphate-nucleotide binding but may allow binding of an AMPylated target for deAMPylation or another substrate to catalyze a distinct PTM. The β-hairpin flap that registers the modifiable target segment to the active site exhibits remarkable structural variability. The corresponding sequences form few well-defined groups that may recognize distinct target proteins. The binding of Beps to promiscuous FicA antitoxins is well conserved, indicating a role of the antitoxin to inhibit enzymatic activity or to serve as a chaperone for the FIC domain before translocation of the Bep into host cells. Taken together, our analysis indicates a remarkable functional plasticity of Beps that is mostly brought about by structural changes in the substrate pocket and the target dock. These findings may guide future structure–function analyses of the highly versatile FIC domains.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2016

Changes in global gene expression profiles induced by HPV 16 E6 oncoprotein variants in cervical carcinoma C33-A cells

We analyzed the effects of the expression of HPV 16 E6 oncoprotein variants (AA-a, AA-c, E-A176/G350, E-C188/G350, E-G350), and the E-Prototype in global gene expression profiles in an in vitro model. E6 gene was cloned into an expression vector fused to GFP and was transfected in C33-A cells. Affymetrix GeneChip Human Transcriptome Array 2.0 platform was used to analyze the expression of over 245,000 coding transcripts. We found that HPV16 E6 variants altered the expression of 387 different genes in comparison with E-Prototype. The altered genes are involved in cellular processes related to the development of cervical carcinoma, such as adhesion, angiogenesis, apoptosis, differentiation, cell cycle, proliferation, transcription and protein translation. Our results show that polymorphic changes in HPV16 E6 natural variants are sufficient to alter the overall gene expression profile in C33-A cells, explaining in part the observed differences in oncogenic potential of HPV16 variants. - Highlights: • Amino acid changes in HPV16 E6 variants modulate the transciption of specific genes. • This is the first comparison of global gene expression profile of HPV 16 E6 variants. • Each HPV 16 E6 variant appears to have its own molecular signature.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

scRNA seq of an F1 cross of Marek’s disease resistant and susceptible chickens identifies allele specific expression signatures enriched in transcription modulators

Abstract Marek’s disease (MD), a T cell lymphoma disease in chickens, is caused by the Marek’s disease virus (MDV) found ubiquitously in the poultry industry. Genetically resistant Line 6 3 (L6) and susceptible Line 7 2 (L7) chickens have been instrumental to research on avian immune system response to MDV infection. In this study we characterized molecular signatures unique to splenic immune cell types across different genetic backgrounds 6 days after infection. Using three populations, L6, L7, and an F1 cross between L6xL7, we evaluated the immune cell transcriptome of responding cell types using single cell RNA sequencing. Several MDV genes were found expressed mainly in cytotoxic T cells while ICP4 and MEQ MDV genes were expressed across infected cell types. Using the F1 we quantified allele specific expression (ASE) of biallelic SNPs and found biased expression of parental alleles specific to immune cell subtypes. We identified 22 SNPs with ASE in response to MDV infection mapped to gene rich regions surrounding 59 genes of critical importance for chromatin remodeling and transcriptional regulation. Histone deacetylase genes (HDAC1 and HDAC8) had increased expression of L6 alleles, while small nuclear RNA genes (SNORA68 and SNORA72) expressed higher levels of L7 alleles with infection in T cell subsets. SNPs with ASE also mapped genes important for an adequate immune response including GNLY (cytotoxic activity) and PDIA3 (component of MHC class I peptide loading complex), and genes known to promote viral replication (MCM5 and EIF3M). These results show that functional variants associated with susceptibility to MD may have a bigger impact in subsets of immune cell types, and by characterizing the transcriptomes of these subtypes we can unravel molecular signatures specific to MD genomic resistance.

Science & Technology - Other Topics↗
DOE OSTI2015

2015 Los Alamos Space Weather Summer School Research Reports

The fifth Los Alamos Space Weather Summer School was held June 1st - July 24th, 2015, at Los Alamos National Laboratory (LANL). With renewed support from the Institute of Geophysics, Planetary Physics, and Signatures (IGPPS) and additional support from the National Aeronautics and Space Administration (NASA) and the Department of Energy (DOE) Office of Science, we hosted a new class of five students from various U.S. and foreign research institutions. The summer school curriculum includes a series of structured lectures as well as mentored research and practicum opportunities. Lecture topics including general and specialized topics in the field of space weather were given by a number of researchers affiliated with LANL. Students were given the opportunity to engage in research projects through a mentored practicum experience. Each student works with one or more LANL-affiliated mentors to execute a collaborative research project, typically linked with a larger ongoing research effort at LANL and/or the student’s PhD thesis research. This model provides a valuable learning experience for the student while developing the opportunity for future collaboration. This report includes a summary of the research efforts fostered and facilitated by the Space Weather Summer School. These reports should be viewed as work-in-progress as the short session typically only offers sufficient time for preliminary results. At the close of the summer school session, students present a summary of their research efforts. Titles of the papers included in this report are as follows: Full particle-in-cell (PIC) simulation of whistler wave generation, Hybrid simulations of the right-hand ion cyclotron anisotropy instability in a sub-Alfvénic plasma flow, A statistical ensemble for solar wind measurements, Observations and models of substorm injection dispersion patterns, Heavy ion effects on Kelvin-Helmholtz instability: hybrid study, Simulating plasmaspheric electron densities with a two-component electric field model, Ion and electron heating by whistler turbulence: parametric studies via particle-in-cell simulation, and The statistics of relativistic electron pitch angle distribution in the Earth’s radiation belt based on the Van Allen Probes measurements.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS2006

NASA Dryden Status

This viewgraph presentation reviews the recent activities of NASA Dryden Flight Research Center. Some of the activities are: the delivery of Ikhana, a platform to conduct Earth Science Missions; work on Autonomous Airborne Refueling Demonstration (AARD); progress in developing Quiet Spike, an extendable boom to reduce sonic boom signature; and work on Unmanned Aerial Vehicle Synthetic Aperture Radar (UAVSAR) and Crew Exploration Vehicle (CEV)

Bosworth, John T.↗
NASA NTRS2019

HEX-P: the High-Energy X-Ray Probe

The High-Energy X-ray Probe (HEX-P) is a next-generation high-energy X-ray observatory with broadband (2-200 keV) response that has 40 times the sensitivity of any previous mission in the 10-80 keV band and > 100 times the sensitivity of any previous mission in the 80-200 keV band. With this leap in observational capability, HEX-P will address a broad range of science objectives beyond any planned mission in the hard X-ray bandpass. HEX-P will probe the extreme environments around black holes and neutron stars, map the growth of supermassive black holes, and quantify the effect they have on their environments. HEX-P will resolve the hard X-ray emission from dense regions of our Galaxy to understand the high- energy source populations and investigate dark matter candidate particles through their decay channel signatures. If developed and launched on a timescale similar to Athena, the complementary abilities of the two missions will greatly enhance the Community’s ability to address the important science questions of the hot universe. HEX-P addresses science that is not planned by any flagship-class missions, and is beyond the capability of an Explorer-class mission.

Madsen, Kristin K.↗
DOE OSTI2023

White Paper On Nuclear Structure Reactions and Astrophysics

In preparation for the 2023 NSAC Long Range Plan (LRP), the DNP Town Meeting on Nuclear Structure, Reactions, and Astrophysics was held at Argonne National Laboratory (ANL) on Nov 14-16, 2022. The town meeting brought together 578 members of the low-energy nuclear science community, including 216 in-person attendees and 362 remote participants coming from US national laboratories, a wide range of US universities and other research institutions and universities abroad. Participants met in five topic-oriented and seven cross-cutting and intersecting working groups to discuss progress since the 2015 LRP and identify compelling science opportunities and the resources needed to realize them. These considerations were used during the Town Meeting to determine a set of resolutions outlining the highest priorities for our subfield. The full text of the resolutions endorsed by unanimous consent by the low-energy nuclear science community at the Town Meeting is presented at the end of this executive summary. The reports from all working groups that met during the Town Meeting are included as Secs. 1 to 11 of this Whitepaper. The intellectual challenges for nuclear structure, reactions and astrophysics can be captured in the following questions: What is the nature of the nuclear force that binds protons and neutrons into stable nuclei and rare isotopes, and how do the rich phenomena of nuclear structure and reactions emerge? How do single-nucleon, cluster, and collective degrees of freedom coexist and evolve with increasing proton-neutron imbalance and excitation energies? What are the limits of nuclear existence, and what features arise near and beyond these limits? What are the astrophysical origins of the elements and how did the associated chemical evolution proceed? How do stars evolve, and what nuclear signatures do they leave behind? What is the nature of neutron stars and dense matter? How can the knowledge and technological progress provided by nuclear science best be used to benefit society?

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗