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Results for “Differentiability”

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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

X-ray diffraction, differential scanning calorimetry and evolved gas analysis of aged plutonium tetrafluoride (PuF4)

A 30 year-old PuF4 sample consisting of brown powder (PuF4-b) and pink granules (PuF4-p) was analyzed. X-ray difraction shows the bulk is comprised of three compounds: PuF4, PuO2, and PuF4·1.6H2O. Broadening of PuF4 XRD peaks suggests possible a-damage. After annealing at 650 °C, crystalline PuF4 and PuO2 remain. Thermogravimetric analysis and diferential scanning calorimetry—with simultaneous evolved gas analysis—of the separated PuF4-p and PuF4-b components reveal a distinct sequence of reactions. Dehydration occurs between~90 and 300 °C. Exothermic annealing of the a-damage occurs in two stages: at 350–355 °C and at 555–558 °C. Hydrofuoric acid, fuorine and helium desorb during the frst exotherm. Above 700 °C, PuF4 reacts with PuO2, resulting in oxygen release and mass loss.

PuF4, dsc, differential scanning calorimetry, plut↗
DOE OSTI2019

Statistical detection of differentially abundant ions in mass spectrometry-based imaging experiments with complex designs

Mass Spectrometry Imaging (MSI) characterizes changes in chemical composition between regions of biological samples such as tissues. This translates into a statistical goal of class comparison, i.e. determining analytes that change in abundance between conditions more systematically than as expected by random variation. To reach accurate and reproducible conclusions, statistical analysis must appropriately reflect the initial research question, the design of the MSI experiment, and all the associated sources of variation. This manuscript highlights the importance of following these general statistical principles. Using the example of two case studies with complex experimental designs, and with dierent strategies of data acquisition, we demonstrate the extent to which choices made at key points of this workflow impact the results, and provide suggestions for appropriate design and analysis of MSI experiments that aim at detecting dierentially abundant analytes.

NanoDESI, mass spectrometry, MSIQuickView↗
DOE OSTI2020

Insights into negative differential resistance in MoS 2 Esaki diodes: A first-principles perspective

MoS 2 is a two-dimensional material with a band gap depending on the number of layers and tunable by an external electric field. The experimentally observed intralayer band-to-band tunneling and interlayer band-to-band tunneling in this material present an opportunity for new electronic applications in tunnel field-effect transistors. However, such a widely accepted concept has yet to be been supported by theoretical investigations based on first principles. In this paper, using density functional theory, in conjunction with nonequilibrium Green's function techniques and our electric field gating method, enabled by a large-scale computational approach, we study the relation between band alignment and transmission in planar and side-stack MoS 2 p–i–n junction configurations. Here, we demonstrate the presence of negative differential resistance for both in-plane and interlayer current, a staple characteristic of tunnel diode junctions, and analyze the physical origin of such an effect. Electrostatic potentials, the van der Waals barrier, and a complex band analysis are also examined for a thorough understanding of Esaki diodes.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2019

Searches for scalar leptoquarks and differential cross-section measurements in dilepton–dijet events in proton–proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV with the ATLAS experiment

Searches for scalar leptoquarks pair-produced in proton–proton collisions at $\sqrt{s}$ =13 TeV at the Large Hadron Collider are performed by the ATLAS experiment. A data set corresponding to an integrated luminosity of 36.1 fb -1 is used. Final states containing two electrons or two muons and two or more jets are studied, as are states with one electron or muon, missing transverse momentum and two or more jets. No statistically significant excess above the Standard Model expectation is observed. The observed and expected lower limits on the leptoquark mass at 95% confidence level extend up to 1.29 TeV and 1.23 TeV for first- and second-generation leptoquarks, respectively, as postulated in the minimal Buchmüller–Rückl–Wyler model, assuming a branching ratio into a charged lepton and a quark of 50%. In addition, measurements of particle-level fiducial and differential cross sections are presented for the Z→ ee, Z→ μμ and $ t\bar{t} $ processes in several regions related to the search control regions. Predictions from a range of generators are compared with the measurements, and good agreement is seen for many of the observables. However, the predictions for the Z→ ℓℓ measurements in observables sensitive to jet energies disagree with the data.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Differentiating Vaccine-Related Fowl Cholera from Naturally Occurring Disease

Vaccine-related fowl cholera must be considered when flock mortality increases after use of a live Pasteurella multocida vaccine product. All registered live vaccines serotype as Heddleston 3,4; however, in some regions this is also the most common serotype of outbreak isolates in broiler breeders and turkeys. Therefore, serotyping may not be useful for diagnosing vaccine-related fowl cholera. This project sought to apply a vaccine-specific test to differentiate vaccine-related disease from naturally occurring outbreaks. Results indicate that vaccine strains were commonly isolated from broiler breeders exhibiting signs of fowl cholera post vaccination, but some of these isolates exhibited only serotype 4 antigenicity. The isolates’ lipopolysaccharides, the target antigen for serotyping, contained compositional changes that may explain the varying serotype results and virulence of the commercial preparations. Furthermore, these results suggest that vaccine-related disease may be common in broiler breeders, and live commercial vaccine preparations need to be assessed for serotype and titer prior to use in order to reduce vaccine-related fowl cholera.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Apolipoprotein E plays crucial roles in maintaining bone mass by promoting osteoblast differentiation via ERK1/2 pathway and by suppressing osteoclast differentiation via c-Fos, NFATc1, and NF-κB pathway

Highlights: • Aged ApoE-KO mice exhibit severe osteoporosis compared to WT mice. • ApoE promotes osteoblastogenesis via ERK1/2 pathway. • ApoE inhibits osteoclastogenesis via c-Fos, NFATc1 and NF-κB pathways. Apolipoprotein E (ApoE) plays crucial roles not only in lipid metabolism but also in bone metabolism. Specifically ApoE4, one of major ApoE isoforms, has been demonstrated to be associated with increased risk of developing osteoporosis compared to another major isoform ApoE3. However, the detailed mechanism of how the different ApoE isoforms affect bone metabolism remains unclear. Micro-CT analyses of distal femora demonstrated severely decreased bone mass in 48-week-old female homozygous ApoE-knockout (ApoE-KO) mice compared to age- and gender-matched wild type C57BL/6 J (WT) mice. Physiological levels of either ApoE3 or ApoE4 protein (1–20 μg/ml) significantly increased the expression of osteoblast-related genes and alkaline phosphatase (ALP) activity of primary calvarial osteoblasts by inhibiting extracellular signal-regulated kinase 1/2 (ERK1/2) pathway in a dose-dependent manner, and ApoE3 showed greater osteoblastic induction compared to ApoE4. Furthermore, both ApoE3 and ApoE4 protein inhibited osteoclastogenesis and the expression of osteoclast-related genes of mouse bone marrow derived macrophages (BMDM) via down regulation of c-Fos, nuclear factor of activated T-cells 1 (NFATc1) and nuclear factor-kappa B (NF-κB) pathway. Moreover, ApoE3 showed greater inhibition of c-Fos, dendritic cell-specific transmembrane protein (DC-STAMP), and Cathepsin K gene expression compared to ApoE4. Collectively, ApoE plays crucial roles in preserving bone mass, suggesting that targeting ApoE and its isoforms as a promising treatment candidate of both osteoporosis and hyperlipidemia.

60 APPLIED LIFE SCIENCES↗