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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 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Identification of amino-acid residues in the V protein of peste des petits ruminants essential for interference and suppression of STAT-mediated interferon signaling

Peste des petits ruminants virus (PPRV) causes a fatal disease in small ruminants. V protein of PPRV plays a pivotal role in interfering with host innate immunity by blocking IFNs signaling through interacting with STAT1 and STAT2. In the present study, the results demonstrated that PPRV V protein blocks IFN actions in a dose dependent manner and restrains the translocation of STAT1/2 proteins. We speculate that the translocation inhibition might be caused by the interfering of the downstream of STAT protein. Mutagenesis defines that Cys cluster and Trp motif of PPRV V protein are essential for STAT-mediated IFN signaling. These findings give a new sight for the further studies to understand the delicate mechanism of PPRV to escape the IFN signaling. - Highlights: • PPRV V protein inhibits type I IFN production and blocks its activation. • PPRV V protein negatively regulates activation of ISRE and GAS promoter. • PPRV V protein inhibits nuclear translocation of STAT protein by non-degradation. • PNT and VCT domain of PPRV V protein inhibit IFN transduction. • PPRV V protein binds with STAT protein via some conserved motifs.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2011

Alternating current magnetic susceptibility of a molecular magnet submonolayer directly patterned onto a micro superconducting quantum interference device

We report the controlled integration, via dip pen nanolithography, of monolayer dots of ferritin-based CoO nanoparticles (12 μ{sub B}) into the most sensitive areas of a microSQUID sensor. The nearly optimum flux coupling between these nanomagnets and the microSQUID improves the achievable sensitivity by a factor 10{sup 2}, enabling us to measure the linear susceptibility of the molecular array down to very low temperatures (13 mK). This method opens the possibility of applying ac susceptibility experiments to characterize two-dimensional arrays of single molecule magnets within a wide range of temperatures and frequencies.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2013

Spin-wave interference in microscopic permalloy tubes

We present permalloy coated needles which act as spin-wave resonators. The permalloy coated needles were investigated using microwave absorption spectroscopy. Thereby, we found up to three resonant modes which correspond to constructively interfering azimuthal spin waves. The resonant modes are well reproduced in calculations based on an analytical model for the spin-wave dispersion employing periodic boundary conditions. The dependence of the resonance frequencies on the needles' radii and the external magnetic field is demonstrated experimentally.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2013

Fabrication of gold nanostructures through pulsed laser interference patterning

In this Letter, we report on the experimental development and computational modeling of a simple, one-step method for the fabrication of diverse 2D and 3D periodic nanostructures derived from gold films on silicon substrates and over areas spanning 1 cm{sup 2}. These nanostructures can be patterned on films of thickness ranging from 50 nm to 500 nm with pulsed interfering laser beams. A finite volume-based inhomogeneous multiphase model of the process shows reasonable agreement with the experimentally obtained topographies and provides insights on the flow physics including normal and radial expansion that results in peeling of film from the substrate.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2014

Vibronic phenomena and exciton–vibrational interference in two-dimensional spectra of molecular aggregates

A general theory of electronic excitations in aggregates of molecules coupled to intramolecular vibrations and the harmonic environment is developed for simulation of the third-order nonlinear spectroscopy signals. It is applied in studies of the time-resolved two-dimensional coherent spectra of four characteristic model systems: weakly/strongly vibronically coupled molecular dimers interacting with high/low frequency intramolecular vibrations. The results allow us to (i) classify and define the typical spectroscopic features of vibronically coupled molecules, (ii) separate the cases, when the long-lived quantum coherences due to vibrational lifetime borrowing should be expected, (iii) define when the complete exciton–vibrational mixing occurs, and (iv) when separation of excitonic and vibrational coherences is possible.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Direct measurement of sub-wavelength interference using thermal light and photon-number-resolved detection

We examine thermal light diffracted through a double slit using photon-number-resolved detection to directly measure high-order spatial correlations, and we see sinusoidal modulations of those correlations. The fringe width can, in principal, be made arbitrarily small, and we have experimentally obtained fringe widths as small as 30 nm with 800 nm wavelength light. This extreme sub-wavelength resolution, along with this direct detection technique, offers potential for high precision measurement applications.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Experimental study and effect of particulate interference on the microhardness, wear and microstructural properties of ternary doped coating

This paper studies effects of the composite particle infringement of ZnO/Cr{sub 2}O{sub 3} on zinc rich ternary based coating. The corrosion-degradation property in 3.5% NaCl was investigatedusing polarization technique. The structural characteristics of the multilayer produce coatings were evaluated by scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS). The mechanical response of the coated samples was studied using a diamond base Dura –Scan) micro-hardness tester and a MTR-300 dry abrasive wear tester. The combined effect of the coatings gave highly-improved performance on microhardness, corrosion and wear damage. This also implies that protection of wind-energy structures in marine environments can be achieved by composite strengthening capacity.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Formation of high quality interference fringes from both sides of a suitably designed hololens in the laser Doppler anemometer measurement volume

We report, for the first time to the best of our knowledge, the formation of high quality, evenly spaced, undistorted fringes in the measurement volume of a laser Doppler anemometer from both sides of a suitably designed hololens. Experiments are performed for the analysis of fringes formed at the measurement volume by real time monitoring and actual fringe field analysis techniques. The results indicate the qualitative as well as quantitative improvement of 66.58% in overall average normalised standard deviations of the width of the fringes formed by the proposed imaging configuration than that of the conventional imaging configuration. (laser applications and other topics in quantum electronics)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2010

From a discrete to a continuous model for interpulse interference with a frequency-comb laser

We have investigated correlation patterns generated by a frequency-comb laser in a dispersive unbalanced Michelson interferometer and apply the developed formalism to the case of distance metrology. Due to group velocity dispersion, the position of the brightest fringe of the correlation pattern, which is used for distance determination, cannot be derived by simply using the definition of group refractive index of the dispersive medium. It is shown that the discrete spectrum of the optical frequency comb gives rise to correlation functions which can be represented by a series, namely a discrete correlation series. We have developed a general formalism, valid for any pulse train, extending the discrete model to a continuous model of cross-correlation functions using the Poisson summation. Our model is relevant for any offset and repetition frequency of the frequency comb. From the continuous cross-correlation model we show that, even for a homogeneous dispersive medium the position of the brightest fringe varies nonlinearly for small delay distances and stabilizes for longer ones. We have compared the theoretical results to measurements of pulse propagation in air for path-lengths up to 200 m.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Quantitative x-ray differential-interference-contrast microscopy with independently adjustable bias and shear

We present a quantitative x-ray phase imaging method that can be readily implemented on existing x-ray microscopy facilities. This technique utilizes Fresnel zone plates both as imaging optical elements for magnification and as second-order grating structures for phase-shifting interferometry. By making high-resolution quantitative x-ray phase information widely available, we expect this work to have significant impact on nanoscale biological and material studies.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Imprinting interference fringes in massive optomechanical systems

An interferometric scheme for the creation of momentum superposition states of mechanical oscillators using a quantum mirror kicked by free photons is analyzed. The scheme features ultrafast preparation with immediate detection and should allow for the observation of signatures of momentum superpositions in a massive macroscopic system at nonzero temperatures. It is robust against thermalized initial states, displacement and movement, mirror imperfections, and the measurements' back-actions.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗