The substitution of nickel for cobalt in hot isostatically pressed powder metallurgy UDIMET 700 alloys

NASA Technical Reports Server (NTRS)

Harf, F. H.

1985-01-01

Nickel was substituted in various proportions for cobalt in a series of five hot-isostatically-pressed powder metallurgy alloys based on the UDIMET 700 composition. These alloys were given 5-step heat treatments appropriate for use in turbine engine disks. The resultant microstructures displayed three distinct sizes of gamma-prime particles in a gamma matrix. The higher cobalt-content alloys contained larger amounts of the finest gamma-prime particles, and had the lowest gamma-gamma-prime lattice mismatch. While all alloys had approximately the same tensile properties at 25 and 650 gamma C, the rupture lives at 650 and 760 C peaked in the alloys with cobalt contents between 12.7 and 4.3 pct. Minimum creep rates increased as cobalt contents were lowered, suggesting their correlation with the gamma-prime particle size distribution and the gamma-gamma-prime mismatch. It was also found that, on overaging at temperatures higher than suitable for turbine disk use, the high cobalt-content alloys were prone to sigma phase formation.

Microstructural observations in rapidly-solidified and heat-treated Ni3Al-Cr alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carro, G.; Flanagan, W.F.

1992-08-01

The microstructural development following heat treatments of several rapidly-solidified Ni3Al-Cr and Ni3Al-Cr-B alloys is presented. Depending on composition, the as-solidified samples were either 100 percent gamma-prime phase - in the form of fine antiphase domains (APD) - or a mixture of gamma-prime (APDs) and beta phases. Upon annealing, the as-solidified microstructures transform to either APD-free gamma-prime or mixtures of gamma and gamma-prime phases. For those compositions where the quenched microstructures were 100 percent gamma-prime it was observed that APD coarsening followed conventional grain-growth kinetics, but when gamma phase precipitated on the APD boundaries the rate constant changed abruptly while themore » time exponent remained unaffected. It was also found that alloys containing critical amounts of chromium and boron are susceptible to precipitation of the boride Cr5B3. 14 refs.« less

Microstructural observations in rapidly-solidified and heat-treated Ni3Al-Cr alloys

NASA Technical Reports Server (NTRS)

Carro, G.; Flanagan, W. F.

1992-01-01

The microstructural development following heat treatments of several rapidly-solidified Ni3Al-Cr and Ni3Al-Cr-B alloys is presented. Depending on composition, the as-solidified samples were either 100 percent gamma-prime phase - in the form of fine antiphase domains (APD) - or a mixture of gamma-prime (APDs) and beta phases. Upon annealing, the as-solidified microstructures transform to either APD-free gamma-prime or mixtures of gamma and gamma-prime phases. For those compositions where the quenched microstructures were 100 percent gamma-prime it was observed that APD coarsening followed conventional grain-growth kinetics, but when gamma phase precipitated on the APD boundaries the rate constant changed abruptly while the time exponent remained unaffected. It was also found that alloys containing critical amounts of chromium and boron are susceptible to precipitation of the boride Cr5B3.

Formation of gamma(sup prime)-Ni3Al via the Peritectoid Reaction: gamma + beta (+ Al2O3)=gamma(sup prime)(+ Al2O3)

NASA Technical Reports Server (NTRS)

Copeland, Evan

2008-01-01

The activities of Al and Ni were measured using multi-cell Knudsen effusion-cell mass spectrometry (multi-cell KEMS), over the composition range 8-32 at.%Al and temperature range T=1400-1750 K in the Ni-Al-O system. These measurements establish that equilibrium solidification of gamma(sup prime)-Ni3Al-containing alloys occurs by the eutectic reaction, L (+ Al2O3)=gamma + Beta(+ Al2O3), at 1640 +/- 1 K and a liquid composition of 24.8 +/- 0.2 at.%al (at an unknown oxygen content). The {gamma + Beta (+Al2O3} phase field is stable over the temperature range 1633-1640 K, and gamma(sup prime)-Ni3Al forms via the peritectoid, gamma + Beta (+ Al2O3)=gamma(sup prime) (+ Al2O3), at 1633 +/- 1 K. This behavior is consistent with the current Ni-Al phase diagram and a new diagram is proposed. This new Ni-Al phase diagram explains a number of unusual steady-state solidification structures reported previously and provides a much simpler reaction scheme in the vicinity of the gamma(sup prime)-Ni2Al phase field.

Quaternary and quinary modifications of eutectic superalloys strengthened by delta Ni3Cb lamellae and gamma prime Ni3Al precipitates

NASA Technical Reports Server (NTRS)

Lemkey, F. D.; Mccarthy, G. P.

1975-01-01

By means of a compositional and heat treatment optimization program based on the quaternary gamma/gamma prime-delta, a tantalum modified gamma/gamma prime-delta alloy with improved shear and creep strength combined with better cyclic oxidation resistance was identified. Quinary additions, quaternary adjustments, and heat treatment were investigated. The tantalum modified gamma/gamma prime-delta alloy possessed a slightly higher liquidus temperature and exhibited rupture strength exceeding NASA VIA by approximately three and one-half Larson-Miller parameters (C = 20) above 1000 C. Although improvements in longitudinal mechanical properties were achieved, the shear and transverse strength property goals of the program were not met and present a continuing challenge to the alloy metallurgist.

The Influence of Tungsten on the Chemical Composition of a Temporally Evolving Nanostructure of a Model Ni-Al-Cr Superalloy

NASA Technical Reports Server (NTRS)

Sudbrack, Chantal K.; Isheim, Dieter; Noebe, Ronald D.; Jacobson, Nathan S.; Seidman, David N.

2004-01-01

The influence of W on the temporal evolution of gamma' precipitation toward equilibrium in a model Ni-Al-Cr alloy is investigated by three-dimensional atom-probe (3DAP) microscopy and transmission electron microscopy (TEM). We report on the alloys Ni-10 Al-8.5 Cr (at.%) and Ni-10 Al-8.5 Cr-2 W (at.%), which were aged isothermally in the gamma + gamma' two-phase field at 1073 K, for times ranging from 0.25 to 264 h. Spheroidal-shaped gamma' precipitates, 5-15 nm diameter, form during quenching from above the solvus temperature in both alloys at a high number density (approx. 10(exp 23/cu m). As gamma' precipitates grow with aging at 1073 K, a transition from spheriodal- to cuboidal-shaped precipitates is observed in both alloys. The elemental partitioning and spatially resolved concentration profiles across the gamma' precipitates are obtained as a function of aging time from three-dimensional atom-by-atom reconstructions. Proximity histogram concentration profiles of the quaternary alloy demonstrate that W concentration gradients exist in gamma' precipitates in the as-quenched and 0.25-h aging states, which disappear after 1 h of aging. The diffusion coefficient of W in gamma' is estimated to be 6.2 x 10(exp -20) sq m/s at 1073 K. The W addition decreases the coarsening rate constant, and leads to stronger partitioning of Al to gamma' and Cr to gamma.

Inclusive gamma-ray spectra from psi/3095/ and psi-prime/3684/ decays

NASA Technical Reports Server (NTRS)

Biddick, C. J.; Burnett, T. H.; Masek, G. E.; Miller, E. S.; Smith, J. G.; Stronski, J. P.; Sullivan, M. K.; Vernon, W.; Badtke, D. H.; Barnett, B. A.

1977-01-01

Inclusive gamma-ray experiments were carried out in a e(+)e(-) colliding-beam apparatus with NaI(Tl) arrays as detectors. The inclusive gamma-ray spectra, after cosmic-ray background subtraction, are shown as histograms for the decays of the psi(3095) and psi-prime(3684). The psi spectrum has no significant narrow structure, while the psi-prime spectrum shows at least four peaks. Three major radiative decays of the psi-prime(3684) are found, and their respective branching fractions are computed.

A New Superalloy Enabling Heavy Duty Gas Turbine Wheels for Improved Combined Cycle Efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Detor, Andrew; DiDomizio, Richard; McAllister, Don

The drive to increase combined cycle turbine efficiency from 62% to 65% for the next-generation advanced cycle requires a new heavy duty gas turbine wheel material capable of operating at 1200°F and above. Current wheel materials are limited by the stability of their major strengthening phase (gamma double prime), which coarsens at temperatures approaching 1200°F, resulting in a substantial reduction in strength. More advanced gamma prime superalloys, such as those used in jet engine turbine disks, are also not suitable due to size constraints; the gamma prime phase overages during the slow cooling rates inherent in processing thick-section turbine wheels.more » The current program addresses this need by screening two new alloy design concepts. The first concept exploits a gamma prime/gamma double prime coprecipitation reaction. Through manipulation of alloy chemistry, coprecipitation is controlled such that gamma double prime is used only to slow the growth of gamma prime during slow cooling, preventing over-aging, and allowing for subsequent heat treatment to maximize strength. In parallel, phase field modeling provides fundamental understanding of the coprecipitation reaction. The second concept uses oxide dispersion strengthening to improve on two existing alloys that exhibit excellent hold time fatigue crack growth resistance, but have insufficient strength to be considered for gas turbine wheels. Mechanical milling forces the dissolution of starting oxide powders into a metal matrix allowing for solid state precipitation of new, nanometer scale oxides that are effective at dispersion strengthening.« less

Calculation of the solvus temperature of metastable phases in the Al-Mg-Si alloys

NASA Astrophysics Data System (ADS)

Vasilyev, A. A.; Gruzdev, A. S.; Kuz'min, N. L.

2011-09-01

A procedure has been proposed for the self-consistent calculation of the solvus temperatures of metastable phase precipitates in Al-Mg-Si alloys and the specific energy of their interface with the aluminum matrix. The procedure is based on the results of experimental studies on the kinetics of formation of these precipitates during decomposition of supersaturated solid solutions of quenched Al-Mg-Si alloys, which were carried out by measuring the Young's modulus and electrical resistivity. On the basis of the obtained set of solvus temperatures of the β″-phase, an empirical formula has been proposed for calculating this temperature as a function of the chemical composition of the initial solid solution.

Fracture of single crystals of the nickel-base superalloy PWA 1480E in helium at 22 C

NASA Technical Reports Server (NTRS)

Chen, P. S.; Wilcox, R. C.

1991-01-01

The fracture behavior and deformation of He-charged (at 22 C) single crystals of PWA 1480E Ni-base superalloy were investigated using SEM and TEM techniques to observe the behavior of tensile fractures in notched single crystals with seven different crystal growth orientations: 100-line, 110-line, 111-line, 013-line, 112-line, 123-line, and 223-line. To identify the cleavage plane orientation, a stereoscopic technique, combined with the use of planar gamma-prime morphologies, was applied. It was found that gamma-prime particles were orderly and closely aligned with edges along the 100-line, 010-line, and 001-line-oriented directions of the gamma matrix. Different crystal growth orientations were found not to affect the morphology of gamma-prime particles. The accumulation of dislocations around gamma/gamma-prime interfaces formed strong barriers to subsequent dislocation movement and was the primary strengthening mechanism at room temperature.

Computer simulation of morphological evolution and rafting of {gamma}{prime} particles in Ni-based superalloys under applied stresses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, D.Y.; Chen, L.Q.

Mechanical properties of Ni-based superalloys are strongly affected by the morphology, distribution, and size of {gamma}{prime} precipitates in the {gamma} matrix. The main purpose of this paper is to propose a continuum field approach for modeling the morphology and rafting kinetics of coherent precipitates under applied stresses. This approach can be used to simulate the temporal evolution of arbitrary morphologies and microstructures without any a priori assumption. Recently, the authors applied this approach to the selected variant growth in Ni-Ti alloys under applied stresses using an inhomogeneous modulus approximation. For the {gamma}{prime} precipitates in Ni-based superalloys, the eigenstrain is dilatational,more » and hence the {gamma}{prime} morphological evolution can be affected by applied stresses only when the elastic modulus is inhomogeneous. In the present work, the elastic inhomogeneity was taken into account by reformulating a sharp-interface elasticity theory developed recently by Khachaturyan et al. in terms of diffuse interfaces. Although the present work is for a {gamma}{prime} {minus} {gamma} system, this model is general in a sense that it can be applied to other alloy systems containing coherent ordered intermetallic precipitates with elastic inhomogeneity.« less

A Platinum-Enriched gamma+gamma' Two-Phase Bond Coat on Ni-Base Superalloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Ying; Pint, Bruce A; Haynes, James A

2005-01-01

Pt-enriched {gamma} + {gamma}{prime} two-phase coating was applied to directionally-solidified Ni-based superalloy Ren{acute e} 142 substrates with three different Hf levels (0.02, 0.76, and 1.37 wt.%). The coating was prepared by electroplating a thin layer of Pt on the superalloy followed by a diffusion treatment. The as-deposited coating exhibited a {gamma} + {gamma}{prime} two-phase microstructure with a major composition of Ni-16Al-18Pt-7Cr-9Co (in at.%) along with some incorporation of refractory elements from the substrates. Cyclic oxidation testing at 1100 C in air indicated improved oxidation resistance of the Ren{acute e} 142 alloys with the Pt-enriched {gamma} + {gamma}{prime} coatings. In addition,more » the oxidation resistance of both uncoated and coated alloys was proportional to the Hf content in the substrate. Compared with the single-phase {beta}-(Ni,Pt)Al coating, slightly higher mass gains and localized spallation were observed on the {gamma} + {gamma}{prime} two-phase coating, which might be due to the segregation of refractory elements and high sulfur levels in these superalloy substrates.« less

Structure and creep rupture properties of directionally solidified eutectic gamma/gamma-prime-alpha alloy

NASA Technical Reports Server (NTRS)

Whittenberger, J. D.; Wirth, G.

1982-01-01

A simple ternary gamma/gamma-prime-alpha alloy of nominal composition (wt-%) Ni-32Mo-6Al has been directionally solidified at 17 mm/h and tested in creep rupture at 1073, 1173, and 1273 K. A uniform microstructure consisting of square-shaped Mo fibers in a gamma + gamma-prime matrix was found despite some variation in the molybdenum and aluminum concentrations along the growth direction. Although the steady-state creep rate is well described by the normal stress temperature equation, the stress exponent (12) and the activation energy (580 kJ/mol) are high. The rupture behavior is best characterized by the Larson-Miller parameter where the constant equals 20.

The effect of alloying on gamma and gamma prime in nickel-base superalloys

NASA Technical Reports Server (NTRS)

Dreshfield, R. L.; Wallace, J. F.

1972-01-01

An investigation was conducted to determine the compositional limits of gamma and gamma prime phases in nickel-base superalloys. Fifty-one nickel-base alloys were melted under vacuum and heat treated for 4 hours at 1190 C followed by 1008 hours at 850 C. The alloys had the following composition ranges: A1 4.0 to 13 atomic percent, Cr 6.5 to 20.5 percent, Ti 0.25 to 4.75 percent, Mo 0.0 to 6.0 percent, and W 0.0 to 4.0 percent. The residues from the ammonium sulfate electrolytic extraction for the two-phase alloys were analyzed chemically and by X-ray diffraction. The results of the investigation were used to assemble a mathematical model of the gamma-gamma prime region of the Ni-Al-Cr-Ti-Mo-W system. A computer program was written to analyze the model of the phase diagram. Some of these results are also presented graphically. The resulting model is capable of satisfactorily predicting the compositions of conjugate gamma-gamma prime phases in the alloys investigated and twelve of fifteen commercial superalloys studied.

The Temporal Evolution of the Nanostructure of a Model Ni-Al-Cr Superalloy

NASA Technical Reports Server (NTRS)

Sudbrack, Chantal K.; Yoon, Kevin E.; Noebe, Ronald D.; Seidman, David N.

2004-01-01

The early to the later stages of precipitation of ordered gamma'-precipitates (L1(sub 2)) in Ni-5.2 Al-14.2 Cr (at.%) are studied at 873 K. Precipitates with radii as small as 0.45 nm are characterized fully by three-dimensional atom-probe (3DAP) microscopy. Contrary to what is often assumed by theory or in models, the average precipitate composition is shown to evolve with time, such that solute concentrations decrease toward an equilibrium value given by the solvus lines. Power-law time dependencies of the number density, mean radius, and supersaturations of Al and Cr are discussed in light of theoretical predictions for Ostwald ripening.

Resistance of a directionally solidified gamma/gamma prime-delta eutectic alloy to recrystallization. [Ni-base alloy

NASA Technical Reports Server (NTRS)

Tewari, S. N.; Scheuermann, C. M.; Andrews, C. W.

1976-01-01

A lamellar nickel-base directionally-solidified eutectic gamma/gamma prime-delta alloy has potential as an advanced gas turbine blade material. The microstructural stability of this alloy was investigated. Specimens were plastically deformed by uniform compression or Brinell indentation, then annealed between 750 and 1120 C. Microstructural changes observed after annealing included gamma prime coarsening, pinch-off and spheroidization of delta lamellae, and appearance of an unidentified blocky phase in surface layers. All but the first of these was localized in severely deformed regions, suggesting that microstructural instability may not be a serious problem in the use of this alloy.

Resistance of a gamma/gamma prime - delta directionally solidified eutectic alloy to recrystallization

NASA Technical Reports Server (NTRS)

Tewari, S. N.; Scheuermann, C. M.; Andrews, C. W.

1975-01-01

The lamellar directionally solidified nickel-base eutectic alloy gamma/gamma prime-delta has potential as an advanced turbine blade material. The microstructural stability of this alloy was investigated. Specimens were plastically deformed by uniform compression or Brinell indentation, then annealed between 705 and 1120 C. Microstructural changes observed after annealing included gamma prime coarsening, pinch-off and spheroidization of delta lamellae, and the appearance of an unidentified blocky phase in surface layers. All but the first of these was localized in severely deformed regions, suggesting that microstructural instability is not a serious problem in the use of this alloy.

Microstructural study of the nickel-base alloy WAZ-20 using qualitative and quantitative electron optical techniques

NASA Technical Reports Server (NTRS)

Young, S. G.

1973-01-01

The NASA nickel-base alloy WAZ-20 was analyzed by advanced metallographic techniques to qualitatively and quantitatively characterize its phases and stability. The as-cast alloy contained primary gamma-prime, a coarse gamma-gamma prime eutectic, a gamma-fine gamma prime matrix, and MC carbides. A specimen aged at 870 C for 1000 hours contained these same constituents and a few widely scattered high W particles. No detrimental phases (such as sigma or mu) were observed. Scanning electron microscope, light metallography, and replica electron microscope methods are compared. The value of quantitative electron microprobe techniques such as spot and area analysis is demonstrated.

Maraging superalloys and heat treatment processes

DOEpatents

Korenko, Michael K.; Gelles, David S.; Thomas, Larry E.

1986-01-01

Described herein are nickel-chromium-iron maraging, gamma prime strengthened superalloys containing about 18 to 25 weight percent nickel, about 4 to 8 weight percent chromium, gamma prime forming elements such as aluminum and/or titanium, and a solid solution strengthening element, such as molybdenum. After heat treatment, which includes at least one ausaging treatment and at least one maraging treatment, a microstructure containing gamma prime phase and decomposed Fe-Ni-Cr type martensite is produced.

Fatigue crack propagation behaviour of unidirectionally solidified gamma/gamma-prime-delta eutectic alloys. [Ni-Nb-Al alloys

NASA Technical Reports Server (NTRS)

Bretz, P. E.; Hertzberg, R. W.

1979-01-01

Fatigue crack propagation studies were carried out on unidirectionally solidified gamma/gamma-prime-delta (Ni-Nb-Al) alloys over an aluminum content range of 1.5-2.5% by weight. The variation of Al content of as-grown alloys did not significantly affect the crack growth behavior of these eutectic composites. The results indicate that the addition of Al to the eutectic dramatically improved the FCP behavior. The gamma/gamma-prime-delta alloy exhibited crack growth rates for a given stress intensity range that are an order of magnitude lower than those for the gamma-delta alloy. It is suggested that this difference in FCP behavior can be explained on the basis of stacking fault energy considerations. Extensive delaminations at the crack tip were also revealed, which contributed to the superior fatigue response. Delamination was predominantly intergranular in nature.

The two-photon absorptivity of rotational transitions in the A2 Sigma hyperon + (v prime = O) - X-2 pion (v prime prime = O) gamma band of nitric oxide

NASA Technical Reports Server (NTRS)

Gross, K. P.; Mckenzie, R. L.

1982-01-01

A predominantly single-mode pulsed dye laser system giving a well characterized spatial and temporal output suitable for absolute two-photon absorptivity measurements was used to study the NO gamma(0,0) S11 + R21 (J double prime = 7-1/2) transition. Using a calibrated induced-fluorescence technique, an absorptivity parameter of 2.8 + or - 1.4 x 10 to the minus 51st power cm to the 6th power was obtained. Relative strengths of other rotational transitions in the gamma(0,0) band were also measured and shown to compare well with predicted values in all cases except the O12 (J double prime = 10-1/2) transition.

Microstructural response to heat affected zone cracking of prewelding heat-treated Inconel 939 superalloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gonzalez, M.A., E-mail: mgonzalez@comimsa.com.mx; Martinez, D.I., E-mail: dorairma@yahoo.com; Perez, A., E-mail: betinperez@hotmail.com

2011-12-15

The microstructural response to cracking in the heat-affected zone (HAZ) of a nickel-based IN 939 superalloy after prewelding heat treatments (PWHT) was investigated. The PWHT specimens showed two different microstructures: 1) spherical ordered {gamma} Prime precipitates (357-442 nm), with blocky MC and discreet M{sub 23}C{sub 6} carbides dispersed within the coarse dendrites and in the interdendritic regions; and 2) ordered {gamma} Prime precipitates in 'ogdoadically' diced cube shapes and coarse MC carbides within the dendrites and in the interdendritic regions. After being tungsten inert gas welded (TIG) applying low heat input, welding speed and using a more ductile filler alloy,more » specimens with microstructures consisting of spherical {gamma} Prime precipitate particles and dispersed discreet MC carbides along the grain boundaries, displayed a considerably improved weldability due to a strong reduction of the intergranular HAZ cracking associated with the liquation microfissuring phenomena. - Highlights: Black-Right-Pointing-Pointer Homogeneous microstructures of {gamma} Prime spheroids and discreet MC carbides of Ni base superalloys through preweld heat treatments. Black-Right-Pointing-Pointer {gamma} Prime spheroids and discreet MC carbides reduce the intergranular HAZ liquation and microfissuring of Nickel base superalloys. Black-Right-Pointing-Pointer Microstructure {gamma} Prime spheroids and discreet blocky type MC carbides, capable to relax the stress generated during weld cooling. Black-Right-Pointing-Pointer Low welding heat input welding speeds and ductile filler alloys reduce the HAZ cracking susceptibility.« less

The Cyclic Stress-Strain Behavior of a Single Crystal Nickel-Base Superalloy. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Gabb, Timothy P.

1988-01-01

The cyclic stress-strain response and similar deformation structures of the single crystal nickel based superalloy was described under a specific set of conditions. The isothermal low cycle fatigue response and deformation structures were described at a typical intermediate temperature and at high temperature. Specimens oriented near the (001) and (111) crystallographic orientations were tested at 1050 C, where more moderate orientation effects were expected. This enabled the description of the deformation structures at each of the 2 temperatures and their relationship to the observed cyclic stress-strain behavior. The initial yield strength of all specimens tested at 650 C was controlled by the shearing of the gamma prime precipitates by dislocation pairs. Low cycle fatigue tests at 650 C had cyclic hardening, which was associated with dislocation interactions in the gamma matrix. The initial yield strength of specimens tested at 1050 C was associated with dislocation bypassing of the gamma prime precipitates. Low cycle fatigue tests at 1050 C had cyclic softening, associated with extensive dislocation recovery at the gamma-gamma prime interfaces along with some gamma prime precipitate coarsening.

Theory of phase stabilities and bonding mechanisms in stoichiometric and substoichiometric molybdenum carbide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hugosson, H.W.; Eriksson, O.; Nordstroem, L.

1999-10-01

First principles, total energy methods have been applied to predict the relative stabilities of the four experimentally verified MoC phases: the cubic {delta}(NaCl) phase and the three hexagonal {gamma}(WC), {eta} and {gamma}{sup {prime}}(TiAs) phases. The effect of vacancies on the relative stability of these four phases was investigated using a model structure with ordered vacancies within the carbon sublattice. For stoichiometric MoC, the {gamma} phase was found to be the most stable followed by {gamma}{sup {prime}}, {delta}, and {eta}, but for substoichiometric MoC{sub 0.75}, the order of relative stability was changed and the substoichiometric {delta} phase was found to havemore » the lowest energy followed by {gamma}{sup {prime}} and {gamma}. A study of the electronic structure revealed vacancy induced peaks in the density of state and the electron density attached to these peaks was analyzed and found to emanate from unscreened Mo{endash}Mo bonds through the carbon vacancy site. Finally, the oxygen stabilization of the {gamma}{sup {prime}} MoC phase was studied. {copyright} {ital 1999 American Institute of Physics.}« less

cAMP and forskolin decrease. gamma. -aminobutyric acid-gated chloride flux in rat brain synaptoneurosomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heuschneider, G.; Schwartz, R.D.

1989-04-01

The effects of the cyclic nucleotide cAMP on {gamma}-aminobutyric acid-gated chloride channel function were investigated. The membrane-permeant cAMP analog N{sup 6}, O{sup 2{prime}}-dibutyryladenosine 3{prime},5{prime}-cyclic monophosphate inhibited muscimol-induced {sup 36}Cl{sup {minus}} uptake into rat cerebral cortical synaptoneurosomes in a concentration-dependent manner. The inhibition was due to a decrease in the maximal effect of muscimol, with no change in potency. Similar effects were observed with 8-(4-chlorophenylthio)adenosine 3{prime},5{prime}-cyclic monophosphate, 8-bromoadenosine 3{prime},5{prime}-cyclic monophosphate, and the phosphodiesterase inhibitor isobutylmethylxanthine. The effect of endogenous cAMP accumulation on the {gamma}-aminobutyric acid-gated Cl{sup {minus}} channel was studied with forskolin, an activator of adenylate cyclase. Under identical conditions, inmore » the intact synaptoneurosomes, forskolin inhibited muscimol-induced {sup 36}Cl{sup {minus}} uptake and generated cAMP with similar potencies. Surprisingly, 1,9-dideoxyforskolin, which does not activate adenylate cyclase, also inhibited the muscimol response, suggesting that forskolin and its lipophilic derivatives may interact with the Cl{sup {minus}} channel directly. The data suggest that {gamma}-aminobutyric acid (GABA{sub A}) receptor function in brain can be regulated by cAMP-dependent phosphorylation.« less

The effect of tantalum and carbon on the structure/properties of a single crystal nickel-base superalloy. M.S. Thesis. Final Report

NASA Technical Reports Server (NTRS)

Nguyen, H. C.

1984-01-01

The microstructure, phase chemistry, and creep and hot tensile properties were studied as a function of tantalum and carbon levels in Mar-M247 type single crystal alloys. Microstructural studies showed that several types of carbides (MC, M23C6 and M5C) are present in the normal carbon (0.10 wt % C) alloys after heat treatment. In general, the composition of the MC carbides changes from titanium rich to tantalum rich as the tantalum level in the alloy increases. Small M23C6 carbides are present in all alloys. Tungsten rich M6C carbides are also observed in the alloy containing no tantalum. No carbides are present in the low carbon (0.01 wt % C) alloy series. The morphology of gamma prime is observed to be sensitive to heat treatment and tantalum level in the alloy. Cuboidal gamma prime is present in all the as cast structures. After heat treatment, the gamma prime precipitates tend to have a more spheroidal like morphology, and this tendency increases as the tantalum level decreases. On prolonged aging, the gamma prime reverts back to a cuboidal morphology or under stress at high temperatures, forms a rafted structure. The weight fraction and lattice parameter of the spheroidal gamma prime increases with increasing tantalum content. Changes in the phase chemistry of the gamma prime matrix and gamma prime have also been analyzed using phase extraction techniques. The partitioning ratio decreases for tungsten and aluminum and increases for tantalum as the tantalum content increases for both alloy series; no significant changes occur in the partitioning ratios of the other alloying elements. A reduction in secondary creep rate and an increase in rupture time result from increasing the tantalum content and decreasing the carbon level.

IFN-gamma priming up-regulates IFN-stimulated gene factor 3 (ISGF3) components, augmenting responsiveness of IFN-resistant melanoma cells to type I IFNs.

PubMed

Wong, L H; Hatzinisiriou, I; Devenish, R J; Ralph, S J

1998-06-01

IFN-stimulated gene factor 3 (ISGF3) mediates transcriptional activation of IFN-sensitive genes (ISGs). The component subunits of ISGF3, STAT1alphabeta, STAT2, and p48-ISGF3gamma, are tyrosine phosphorylated before their assembly into a complex. Subsequently, the ISGF3 complex is translocated to the nucleus. We have recently established that the responsiveness of human melanoma cell lines to type I IFNs correlates directly with their intracellular levels of ISGF3 components, particularly STAT1. In the present study, we show that pretreating IFN-resistant melanoma cell lines with IFN-gamma (IFN-gamma priming) before stimulation with type I IFN also results in increased levels of ISGF3 components and enhanced DNA-binding activation of ISGF3. In addition, IFN-gamma priming of IFN-resistant melanoma cell lines increased expression of type I IFN-induced ISG products, including ISG54, 2'-5'-oligoadenylate synthase, HLA class I, B7-1, and ICAM-1 Ags. Furthermore, IFN-gamma priming enhanced the antiviral effect of IFN-beta on the IFN-resistant melanoma cell line, MM96. These results support a role for IFN-gamma priming in up-regulating ISGF3, thereby augmenting the responsiveness of IFN-resistant melanoma cell lines to type I IFN and providing a molecular basis and justification for using sequential IFN therapy, as proposed by others, to enhance the use of IFNs in the treatment of melanoma.

Shear rupture of a directionally solidified eutectic gamma/gamma prime - alpha (Mo) alloy

NASA Technical Reports Server (NTRS)

Harf, F. H.

1978-01-01

Directionally solidified Mo alloys are evaluated to determine the shear rupture strength and to possibly improve it by microstructural and heat treatment variations. Bars of the alloy containing nominally 5.7% Al and 33.5% Mo by weight with balance Ni were directionally solidified at rates between 10 and 100 mm per hour in furnaces with thermal gradients at the liquid-solid interface of 250 or 100 C per cm. A limited number of longitudinal shear rupture tests were conducted at 760 C and 207 MPa in the as - solidified and in several heat treated conditions. It is shown that shear rupture failures are partly transgranular and that resistance to failure is prompted by good fiber alignment and a matrix structure consisting mainly of gamma prime. Well aligned as - solidified specimens sustained the shear stress for an average of 81 hours. A simulated coating heat treatment appeared to increase the transformation of gamma to gamma prime and raised the average shear life of aligned specimens to 111 hours. However, heat treatments at 1245 C and especially at 1190 C appeared to be detrimental by causing partial solutioning of the gamma prime, and reducing lives to 47 and 10 hours, respectively.

Directionally solidified composite systems under evaluation

NASA Technical Reports Server (NTRS)

Ashbrook, R. L.

1974-01-01

The directionally solidified eutectic in-situ composites being evaluated for use as turbine materials range from ductile-ductile systems, where both matrix and reinforcement are ductile, to brittle-brittle systems, where both phases are brittle. The alloys most likely to be used in gas turbine engines in the near term are the lamellar ductile-semi ductile alloys gamma prime-delta, Ni3Al-Ni3Nb and gamma/gamma prime-delta Ni,Cr,Cb,Al/Ni3Al-Ni3Nb and the fibrous ductile-brittle alloys M-MC CoTaC or NiTaC and M-M7C3(Co,Cr,Al)-(Cr,Co)7C3. The results of tests are given which indicate that gamma prime strengthened NiTaC alloys and a (Co,Cr,Al)7C3 have greater tensile strength than the strongest superalloys at temperatures up to about 600 C. The gamma prime-delta and gamma/gamma prime-delta alloys in the Ni,Al,Nb(Cr) systems have greater tensile strength than the superalloys at temperatures greater than 800 C. At low stresses fibrous carbide reinforced eutectic alloys have longer lives at high temperatures than the strongest superalloys. Lamellar delta, Ni3Nb reinforced eutectic alloys have longer lives at high temperatures than the strongest superalloys at all stresses. The experience currently being gained in designing with the brittle ceramics SiC and Si3N4 may eventually be applied to ceramic matrix eutectic in-situ composites. However, the refractory metal fiber reinforced brittle-ductile systems may find acceptance as turbine materials before the ceramic-ceramic brittle-brittle systems.

A study of interdiffusion in beta + gamma/gamma + gamma prime Ni-Cr-Al. M.S. Thesis. Final Report

NASA Technical Reports Server (NTRS)

Carol, L. A.

1985-01-01

Ternary diffusion in the NiCrAl system at 1200 C was studied with beta + gamma/gamma + gamma prime infinite diffusion couples. Interdiffusion resulted in the formation of complex, multiphase diffusion zones. Concentration/distance profiles for Cr and Al in the phases present in the diffusion zone were measured after 200 hr. The Ni-rich portion of the NiCrAl phase diagram (1200 C) was also determined. From these data, bulk Cr and Al profiles were calculated and translated to diffusion paths on the ternary isotherm. Growth layer kinetics of the layers present in the diffusion zone were also measured.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sigaud, Samuel; Goldsmith, Carroll-Ann W.; Zhou Hongwei

Epidemiological studies reveal increased incidence of lung infection when air pollution particle levels are increased. We postulate that one risk factor for bacterial pneumonia, prior viral infection, can prime the lung for greater deleterious effects of particles via the interferon-gamma (IFN-{gamma}) characteristic of successful host anti-viral responses. To test this postulate, we developed a mouse model in which mice were treated with {gamma}-interferon aerosol, followed by exposure to concentrated ambient particles (CAPs) collected from urban air. The mice were then infected with Streptococcus pneumoniae and the effect of these treatments on the lung's innate immune response was evaluated. The combinationmore » of IFN-{gamma} priming and CAPs exposure enhanced lung inflammation, manifest as increased polymorphonuclear granulocyte (PMN) recruitment to the lung, and elevated expression of pro-inflammatory cytokine mRNAs. Combined priming and CAPs exposure resulted in impaired pulmonary bacterial clearance, as well as increased oxidant production and diminished bacterial uptake by alveolar macrophages (AMs) and PMNs. The data suggest that priming and CAPs exposure lead to an inflamed alveolar milieu where oxidant stress causes loss of antibacterial functions in AMs and recruited PMNs. The model reported here will allow further analysis of priming and CAPs exposure on lung sensitivity to infection.« less

Fatigue properties of MA 6000E, a gamma-prime strengthened ODS alloy. [Oxide Dispersion Strengthened Ni-base alloy for gas turbine blade applications

NASA Technical Reports Server (NTRS)

Kim, Y. G.; Merrick, H. F.

1980-01-01

MA 6000E is a corrosion resistant, gamma-prime strengthened ODS alloy under development for advanced turbine blade applications. The high temperature, 1093 C, rupture strength is superior to conventional nickel-base alloys. This paper addresses the fatigue behavior of the alloy. Excellent properties are exhibited in low and high cycle fatigue and also thermal fatigue. This is attributed to a unique combination of microstructural features, i.e., a fine distribution of dispersed oxides and other nonmetallics, and the highly elongated grain structure which advantageously modify the deformation characteristics and crack initiation and propagation modes from that characteristic of conventional gamma-prime hardened superalloys.

Perforin and gamma interferon expression are required for CD4+ and CD8+ T-cell-dependent protective immunity against a human parasite, Trypanosoma cruzi, elicited by heterologous plasmid DNA prime-recombinant adenovirus 5 boost vaccination.

PubMed

de Alencar, Bruna C G; Persechini, Pedro M; Haolla, Filipe A; de Oliveira, Gabriel; Silverio, Jaline C; Lannes-Vieira, Joseli; Machado, Alexandre V; Gazzinelli, Ricardo T; Bruna-Romero, Oscar; Rodrigues, Mauricio M

2009-10-01

A heterologous prime-boost strategy using plasmid DNA, followed by replication-defective recombinant adenovirus 5, is being proposed as a powerful way to elicit CD4(+) and CD8(+) T-cell-mediated protective immunity against intracellular pathogens. We confirmed this concept and furthered existing research by providing evidence that the heterologous prime-boost regimen using the gene encoding amastigote surface protein 2 elicited CD4(+) and CD8(+) T-cell-mediated protective immunity (reduction of acute parasitemia and prolonged survival) against experimental infection with Trypanosoma cruzi. Protective immunity correlated with the presence of in vivo antigen-specific cytotoxic activity prior to challenge. Based on this, our second goal was to determine the outcome of infection after heterologous prime-boost immunization of perforin-deficient mice. These mice were highly susceptible to infection. A detailed analysis of the cell-mediated immune responses in immunized perforin-deficient mice showed an impaired gamma interferon (IFN-gamma) secretion by immune spleen cells upon restimulation in vitro with soluble recombinant antigen. In spite of a normal numeric expansion, specific CD8(+) T cells presented several functional defects detected in vivo (cytotoxicity) and in vitro (simultaneous expression of CD107a/IFN-gamma or IFN-gamma/tumor necrosis factor alpha) paralleled by a decreased expression of CD44 and KLRG-1. Our final goal was to determine the importance of IFN-gamma in the presence of highly cytotoxic T cells. Vaccinated IFN-gamma-deficient mice developed highly cytotoxic cells but failed to develop any protective immunity. Our study thus demonstrated a role for perforin and IFN-gamma in a number of T-cell-mediated effector functions and in the antiparasitic immunity generated by a heterologous plasmid DNA prime-adenovirus boost vaccination strategy.

The effect of thermal cycling to 1100 C on the alpha /Mo/ phase in directionally solidified gamma/gamma-prime-alpha alloys

NASA Technical Reports Server (NTRS)

Harf, F. H.

1981-01-01

Specimens of gamma/gamma-prime-alpha (Mo) eutectic alloy were thermally cycled or isothermally exposed at temperatures of 1075 to 1100 C. Transmission electron microscopy examination of cycled specimens indicated that even an exposure of 10 minutes effected noticeable changes in the shape of the alpha phase, and that the changes were cumulative as more cycles were added. The cross sections of fine, smooth fibers changed from rectangles to octagons, while lamellae and irregular shapes spheroidized. These effects are attributed to the differences in thermal expansion coefficients between the alpha phase and the gamma/gamma-prime matrix, and to the higher diffusion rates prevailing at elevated temperatures. Where the configuration of the alpha phase is a simple shape, such as a fiber, increasing the temperature eventually brings about a stress free interface between the alpha phase and the matrix by differential thermal expansion. Where the shape of the alpha phase is more complex, a stressed interface persists to higher temperatures where diffusion produces the more drastic morphological changes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryan, Q.C.

There are two nonallelic human {gamma} globin genes located on the short arm of chromosome No. 11 in the order 5{prime}-{sup G}{sub {gamma}}-{sup A}{sub {gamma}}-3{prime}. Various modifications of the two {gamma} genes have been reported and include: deletions, triplications, quadruplications and recently a quintuplication. These are generally created by one or more unequal crossovers in the {gamma} globin gene regions on adjacent chromosomes. During the course of looking for a {gamma}{sup {degree}} thalassemia, which might be due to a crossover of looking for a {gamma} genes, two cases were found in the family W. Bgl II mapping studies showed amore » 5 kb deletion at the {gamma} gene loci in these individuals. The Bgl II fragment from the {gamma} gene loci of R.W. was cloned into the phage vector QR1. Phage mapping showed that two out of the three Pst I sites within the Bgl II fragment were missing which suggested that the crossover might have occurred within the {gamma} gene, possibly within the {gamma}IVS II region. Sequence analysis of the cloned fragment revealed an unusual sequence which had no sequence homology with the {gamma} gene region except for a small 264 bp region near the 3{prime} end. The orientation of the 264 bp fragment is inverted relative to homologous sequences in the {sup G}{sub {gamma}} and {sup A}{sub {gamma}} IVS II. The unusual sequence was computer analyzed for homology with every DNA sequence file in the EMBL database and GenBank and did not show any significant homologies to all the available DNA sequences except for the 264 bp {gamma}IVS II homology.« less

Hot hardness of nickel-rich nickel-chromium-aluminum alloys

NASA Technical Reports Server (NTRS)

Levine, S. R.

1976-01-01

Rockwell A hardness of cast nickel-chromium-aluminum (NiCrAl) alloys was examined from ambient to 1150 K and compared to cast NiAl and IN-100. Alloy constitution was either gamma, gamma prime + gamma or gamma + beta + alpha + gamma prime. Below 1000 K beta containing NiCrAl alloys have hardnesses comparable to IN-100; above 1000 K they soften faster than IN-100. At 1150 K the hardness of beta-containing NiCrAl alloys decreases with increasing beta-content. The beta-containing NiCrAl alloys were harder than beta-NiAl. The ultimate tensile strengths of the NiCrAl alloys were estimated. The effects of NiCrAl coatings on strength and fatigue life of cooled turbine components were deduced.

Microstructural observations in rapidly-solidified and heat-treated Ni sub 3 Al-Cr alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carro, G.; Flanagan, W.F.

1992-01-01

In this paper , the microstructural development following heat treatments of several rapidly-solidified Ni{sub 3}Al-Cr and Ni{sub 3}Al-Cr-B alloys is presented. Depending on composition, the as-solidified samples were either 100% {gamma} phase-in the form of fine anti-phase domains (APD)-or a mixture of {gamma} (APDs) and {beta} phases. Upon annealing, the as-solidified microstructures transform to either APD-free {gamma}or mixtures of {gamma}and {gamma}{prime} phases. For those compositions where the quenched microstructures were 100{gamma}{prime} it was observed that APD coarsening followed conventional grain-growth kinetics, but when {gamma} phase precipitated on the APD boundaries the rate constant changed abruptly while the time exponent remainedmore » unaffected. It was also found that alloys containing critical amounts of chromium and boron are susceptible to precipitation of the boride Cr{sub 5}B{sub 3}.« less

The effect of hydrogen and microstructure on the deformation and fracture behavior of a single crystal nickel-base superalloy. Final Report Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Walston, William S.

1990-01-01

A study was conducted on the effects of internal hydrogen and microstructure on the deformation and fracture of a single crystal nickel-base superalloy. In particular, room temperature plane strain fracture toughness and tensile tests were performed on hydrogen-free and hydrogen charged samples of PWA 1480. The role of microstructure was incorporated by varying the levels of porosity and eutectic gamma/gamma prime through hot isostatic pressing and heat treatment. The room temperature behavior of PWA 1480 was unusual because precipitate shearing was not the primary deformation mechanism at all strains. At strains over 1 percent, dislocations were trapped in the gamma matrix and an attempt was made to relate this behavior to compositional differences between PWA 1480 and other superalloys. Another unique feature of the tensile behavior was cleavage of the eutectic gamma/gamma prime, which is believed to initiate the failure process. Fracture occurred on (111) planes and is likely a result of shear localization along these planes. Elimination of the eutectic gamma/gamma prime greatly improved the tensile ductility, but pososity had no effect on tensile properties. Large quantities of hydrogen (1.74 at. percent) were gas-phase charged into the material, but surprisingly this was not a function of the amount of porosity or eutectic gamma/gamma prime present. Desorption experiments suggest that the vast majority of hydrogen is at reversible lattice trapping sites. This large, uniform concentration of hydrogen dramatically reduced the tensile strain to failure, but only slightly affected the reduction in area. Available hydrogen embrittlement models were examined in light of these results and it was found that the hydrogen enhanced localized plasticity model can explain much of the tensile behavior. K(IC) fracture toughness tests were conducted, but it was necessary to also perform J(IC) tests to provide valid data.

Ways of making-sense: Local gamma synchronization reveals differences between semantic processing induced by music and language.

PubMed

Barraza, Paulo; Chavez, Mario; Rodríguez, Eugenio

2016-01-01

Similar to linguistic stimuli, music can also prime the meaning of a subsequent word. However, it is so far unknown what is the brain dynamics underlying the semantic priming effect induced by music, and its relation to language. To elucidate these issues, we compare the brain oscillatory response to visual words that have been semantically primed either by a musical excerpt or by an auditory sentence. We found that semantic violation between music-word pairs triggers a classical ERP N400, and induces a sustained increase of long-distance theta phase synchrony, along with a transient increase of local gamma activity. Similar results were observed after linguistic semantic violation except for gamma activity, which increased after semantic congruence between sentence-word pairs. Our findings indicate that local gamma activity is a neural marker that signals different ways of semantic processing between music and language, revealing the dynamic and self-organized nature of the semantic processing. Copyright © 2015 Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang Lin, E-mail: zhanglincsu@163.com; Liu Hengsan, E-mail: lhsj63@sohu.com; He Xinbo, E-mail: xb_he@163.com

The characteristics of rapidly solidified FGH96 superalloy powder and the thermal evolution behavior of carbides and {gamma} Prime precipitates within powder particles were investigated. It was observed that the reduction of powder size and the increase of cooling rate had transformed the solidification morphologies of atomized powder from dendrite in major to cellular structure. The secondary dendritic spacing was measured to be 1.02-2.55 {mu}m and the corresponding cooling rates were estimated to be in the range of 1.4 Multiplication-Sign 10{sup 4}-4.7 Multiplication-Sign 10{sup 5} K{center_dot}s{sup -1}. An increase in the annealing temperature had rendered the phase transformation of carbides evolvingmore » from non-equilibrium MC Prime carbides to intermediate transition stage of M{sub 23}C{sub 6} carbides, and finally to thermodynamically stable MC carbides. The superfine {gamma} Prime precipitates were formed at the dendritic boundaries of rapidly solidified superalloy powder. The coalescence, growth, and homogenization of {gamma}' precipitates occurred with increasing annealing temperature. With decreasing cooling rate from 650 Degree-Sign C{center_dot}K{sup -1} to 5 Degree-Sign C{center_dot}K{sup -1}, the morphological development of {gamma} Prime precipitates had been shown to proceed from spheroidal to cuboidal and finally to solid state dendrites. Meanwhile, a shift had been observed from dendritic morphology to recrystallized structure between 900 Degree-Sign C and 1050 Degree-Sign C. Moreover, accelerated evolution of carbides and {gamma}' precipitates had been facilitated by the formation of new grain boundaries which provide fast diffusion path for atomic elements. - Highlights: Black-Right-Pointing-Pointer Microstructural characteristic of FGH96 superalloy powder was investigated. Black-Right-Pointing-Pointer The relation between microstructure, particle size, and cooling rate was studied. Black-Right-Pointing-Pointer Thermal evolution behavior of {gamma} Prime and carbides in loose FGH96 powder was studied.« less

Creep and Fatigue Interaction Characteristics of PWA1484

DTIC Science & Technology

2009-03-01

Tungsten) , 5.6% Al (aluminum) , 9% Ta (tantalum) , 3% Re (rhenium) , .1% Hf (hafnium) , and 59.3% Ni (nickel) by weight [1]. The alloy was invented...Work by Hael Mughrabi sought to determine the effect that the rafting behavior of the gamma prime precipitates had on the creep performance of...inclusions and in-homogeneities in 1961 [6]. Mughrabi further states that there is a tensile stress present in the gamma prime phase and a compressive

Precipitation hardenable iron-nickel-chromium alloy having good swelling resistance and low neutron absorbence

DOEpatents

Korenko, Michael K.; Merrick, Howard F.; Gibson, Robert C.

1980-01-01

An iron-nickel-chromium age-hardenable alloy suitable for use in fast breeder reactor ducts and cladding which utilizes the gamma-double prime strengthening phase and characterized in having a morphology of the gamma-double prime phase enveloping the gamma-prime phase and delta phase distributed at or near the grain boundaries. The alloy consists essentially of about 40-50% nickel, 7.5-14% chromium, 1.5-4% niobium, 0.25-0.75% silicon, 1-3% titanium, 0.1-0.5% aluminum, 0.02-0.1% carbon, 0.002-0.015% boron, and the balance iron. Up to 2% manganese and up to 0.01% magnesium may be added to inhibit trace element effects; up to 0.1% zirconium may be added to increase radiation swelling resistance; and up to 3% molybdenum may be added to increase strength.

Investigation of Advanced Processed Single-Crystal Turbine Blade Alloys

NASA Technical Reports Server (NTRS)

Peters, B. J.; Biondo, C. M.; DeLuca, D. P.

1995-01-01

This investigation studied the influence of thermal processing and microstructure on the mechanical properties of the single-crystal, nickel-based superalloys PWA 1482 and PWA 1484. The objective of the program was to develop an improved single-crystal turbine blade alloy that is specifically tailored for use in hydrogen fueled rocket engine turbopumps. High-gradient casting, hot isostatic pressing (HIP), and alternate heat treatment (HT) processing parameters were developed to produce pore-free, eutectic-free microstructures with different (gamma)' precipitate morphologies. Test materials were cast in high thermal gradient solidification (greater than 30 C/cm (137 F/in.)) casting furnaces for reduced dendrite arm spacing, improved chemical homogeneity, and reduced interdendritic pore size. The HIP processing was conducted in 40 cm (15.7 in.) diameter production furnaces using a set of parameters selected from a trial matrix study. Metallography was conducted on test samples taken from each respective trial run to characterize the as-HIP microstructure. Post-HIP alternate HT processes were developed for each of the two alloys. The goal of the alternate HT processing was to fully solution the eutectic gamma/(gamma)' phase islands and to develop a series of modified (gamma)' morphologies for subsequent characterization testing. This was accomplished by slow cooling through the (gamma)' solvus at controlled rates to precipitate volume fractions of large (gamma)'. Post-solution alternate HT parameters were established for each alloy providing additional volume fractions of finer precipitates. Screening tests included tensile, high-cycle fatigue (HCF), smooth and notched low-cycle fatigue (LCF), creep, and fatigue crack growth evaluations performed in air and high pressure (34.5 MPa (5 ksi)) hydrogen at room and elevated temperature. Under the most severe embrittling conditions (HCF and smooth and notched LCF in 34.5 MPa (5 ksi) hydrogen at 20 C (68 F), screening test results showed increases in fatigue life typically on the order of 1OX, when compared to the current Space Shuttle Main Engine (SSME) Alternate Turbopump (AT) blade alloy (PWA 1480).

The effect of heat treatment on microfissuring in alloy 718

NASA Technical Reports Server (NTRS)

Thompson, R. G.; Dobbs, J. R.; Mayo, D. E.

1986-01-01

Changes in the microfissuring susceptibility of alloy 718 due to solution annealing and age hardening are studied. The effects of Ni3Nb (delta) precipitation during solution annealing and gamma-prime + gamma-double-prime precipitation during age hardening on microfissuring are investigated. It is observed that solution annealing reduces microfissuring and age hardening increases it, and the two precipitates do not affect microfissuring susceptibility. Potential causes for the detected intergranular segregation of the alloy are discussed.

Influence of transition group elements on the stability of the δ- and η-phase in nickelbase alloys

NASA Astrophysics Data System (ADS)

Bäker, Martin; Rösler, Joachim; Hentrich, Tatiana; Ackland, Graeme

2018-01-01

To improve the high-temperature capability of 718-type wrought nickel-base superalloys, the γ \\prime -phase ({{Ni}}3{Al}) can be stabilized. However, this also reduces the size of the forging window because forging has to be done above the γ \\prime - and below the solvus temperature of the phase that is used to enable fine-grain forging, i.e. the δ-phase of {{Ni}}3{Nb} type or the η-phase of {{Ni}}3{Ti}-type. Understanding the influence of alloying elements on the formation of these phases is therefore important. In this paper, density functional theory calculations at 0 K are performed to determine the stabilizing effect of aluminium and of the transition group elements on the stability of the δ-phase and η-phase. Most of the transition group elements of 5th and 6th period stabilize the δ-phase, whereas the stabilizing effect on the η-phase is weaker. According to the calculations, Mo, Tc, W, Re, and Os may be expected to stabilize the δ-phase but not the η-phase, whereas Al and Zn strongly stabilize the η-phase. V, Zr, Ru, Rh, Pd, Ag, Cd, Hf, Ta, Ir, Pt, Au, and Hg stabilize both phases. For some elements (Cr, Mn, Fe, Co), magnetic effects in the δ and especially in the η-phase are shown to be significant at the concentrations studied here.

Creep shear behavior of the oxide dispersion strengthened superalloy MA 6000E

NASA Technical Reports Server (NTRS)

Glasgow, T. K.

1981-01-01

The shear rupture life of the oxide dispersion strengthened (ODS) superalloy MA 6000E was determined at 650 and 760 C was 250 MPa. Comparisons were made at 760 C with the conventional cast superalloy B-1900+Hf, the ODS alloy MA 754, and the directionally solidified eutectic alloy gamma/gamma prime-delta was 170 MPa, and for B-1900+Hf was 360 MPa. The ODS alloy MA 6000E and gamma/gamma prime-delta failed with very little indication of ductile accommodation. Both MA 754 and B-1900+Hf showed some ductile tearing. Fracture surfaces of the ODS alloy MA 754 showed discontinuities similar size, shape, and roughness to its grain structure, but the fracture surfaces of MA 6000E were much smoother than its grain boundaries.

Coatings for directional eutectics. [for corrosion and oxidation resistance

NASA Technical Reports Server (NTRS)

Felten, E. J.; Strangman, T. E.; Ulion, N. E.

1974-01-01

Eleven coating systems based on MCrAlY overlay and diffusion aluminide prototypes were evaluated to determine their capability for protecting the gamma/gamma prime-delta directionally solidified eutectic alloy (Ni-20Cb-6Cr-2.5Al) in gas turbine engine applications. Furnace oxidation and hot corrosion, Mach 0.37 burner-rig, tensile ductility, stress-rupture and thermomechanical fatigue tests were used to evaluate the coated gamma/gamma prime-delta alloy. The diffusion aluminide coatings provided adequate oxidation resistance at 1144 K (1600 F) but offered very limited protection in 114 K (1600 F) hot corrosion and 1366 K (2000 F) oxidation tests. A platinum modified NiCrAlY overlay coating exhibited excellent performance in oxidation testing and had no adverse effects upon the eutectic alloy.

Transverse tensile and stress rupture properties of gamma/gamma prime-delta directionally solidified eutectic

NASA Technical Reports Server (NTRS)

Gray, H. H.

1976-01-01

Tensile and stress rupture properties were determined primarily at 760 C for specimens oriented at various angles (0 deg, 10 deg, 45 deg, and 90 deg) from the solidification direction of bars and/or slabs of the Ni-20Cb-6Cr-2.5A (gamma/gamma prime-delta) eutectic. Threaded-head specimens yielded longer rupture lives with significantly less scatter than did tapered-head specimens. Miniature specimens are suitable for determining traverse tensile and rupture properties of 1.2 centimeter diameter bar stock. The 300 hour rupture stress at 760 C for specimens oriented at 10 deg from the solidification direction was reduced from 740 to 460 MPa, and to 230 MPa for material oriented at either 45 deg or 90 deg.

Gamma Prime Precipitation, Dislocation Densities, and TiN in Creep-Exposed Inconel 617 Alloy

NASA Astrophysics Data System (ADS)

Krishna, Ram; Atkinson, Helen V.; Hainsworth, Sarah V.; Gill, Simon P.

2016-01-01

Inconel 617 is a solid-solution-strengthened Ni-based superalloy with a small amount of gamma prime (γ') present. Here, samples are examined in the as-received condition and after creep exposure at 923 K (650 °C) for 574 hours and 45,000 hours and at 973 K (700 °C) for 4000 hours. The stress levels are intermediate (estimated, respectively, as of the order of 350, 275, and 200 MPa) and at levels of interest for the future operation of power plant. The hardness of the specimens has been measured in the gage length and the head. TEM thin foils have been obtained to quantify dislocation densities (3.5 × 1013 for the as-received, 5.0 × 1014, 5.9 × 1014, and 3.5 × 1014 lines/m2 for the creep-exposed specimens, respectively). There are no previous data in the literature for dislocation densities in this alloy after creep exposure. There is some evidence from the dislocation densities that for the creep-exposed samples, the higher hardness in the gage length in comparison with the creep test specimen head is due to work hardening rather than any other effect. Carbon replicas have been used to extract gamma prime precipitates. The morphology of γ' precipitates in the `as-received' condition was spheroidal with an average diameter of 18 nm. The morphology of these particles does not change with creep exposure but the size increases to 30 nm after 574 hours at 923 K (650 °C) but with little coarsening in 45,000 hours. At 973 K (700 °C) 4000 hours, the average gamma prime size is 32 nm. In the TEM images of the replicas, the particles overlap, and therefore, a methodology has been developed to estimate the volume fraction of gamma prime in the alloy given the carbon replica film thickness. The results are 5.8 vol pct in the as-received and then 2.9, 3.2, and 3.4 vol pct, respectively, for the creep-exposed specimens. The results are compared with predictions from thermodynamic analysis given the alloy compositions. Thermodynamic prediction shows that nitrogen content is important in determining the gamma prime volume fraction. This has not previously been identified in the literature. The higher the nitrogen content, the lower the gamma prime volume fraction. This may explain inconsistencies between previous experimental estimates of gamma prime volume fraction in the literature and the results here. The observed decrease in the γ' volume fraction with creep exposure would correspond to an increase in TiN. At present, there are insufficient experimental data to prove that this predicted relationship occurs in practice. However, it is observed that there is a higher volume fraction of TiN precipitates in the gage length of a creep sample than in the head. This suggests that secondary TiN particles are precipitating at the expense of existing γ' due to the ingress of N from the atmosphere, possibly via creep cracks penetrating in from the surface of the gage length. This effect is not expected to be observed in real components which are much larger and operate in different atmospheres. However, this highlights the need to be conscious of this possibility when carrying out creep testing.

The effect of tantalum on the structure/properties of two polycrystalline nickel-base superalloys: B-1900 + Hf MAR-M247. M.S. Thesis, Final Report

NASA Technical Reports Server (NTRS)

Janowski, G. M.

1985-01-01

The microstructure, phase compositions, and phase fractions were studied in conventionally cast B-1900 + Hf and both conventionally cast and directionally solidified MAR-M247 as a function of tantalum concentration. The hot tensile and creep rupture properties of the solutionized and aged MAR-M247-type alloys were also determined as a function of tantalum level. The effects of tantalum on the microstructure and phase compositions of B-1900 + Hf and MAR-M247 (conventionally cast and directionally solidified) were found to be very similar. The addition of tantalum to the as cast and heat treated alloys was shown to cause the partial replacement of the Hf in the MC carbides by Ta, although the degree of replacement was decreased by the solutionizing and aging heat treatment. The gamma prime and minor phase fractions (primarily MC type carbides) both increased approximately linearly with tantalum concentration. The gamma prime phase compositions were relatively insensitive to tantalum variations with the exception of the tantalum and/or hafnium levels. Bulk tantalum additions increased the tantalum, chromium, and cobalt levels of the gamma phase in both alloy series. The increase in the concentrations of the latter two elements in the gamma phase was a result of the decrease in the gamma phase fraction with increasing bulk tantalum concentration and constant gamma/gamma prime partitioning ratio. Tantalum additions increased the yield stress and ultimate tensile strength of the directionally solidified MAR-M247 type alloys and had no significant effect on ductility.

1000 to 1300 K slow plastic compression properties of Al-deficient NiAl

NASA Technical Reports Server (NTRS)

Whittenberger, J. D.; Kumar, K. S.; Mannan, S. K.

1991-01-01

Nickel aluminides containing 37, 38.5 and 40 at. pct Al have been fabricated by XD synthesis and hot pressing. Such materials were compression tested in air under constant velocity conditions between 1000 and 1300 K. Examination of the microstructures of hot pressed and compression tested aluminides indicated that the structure consisted of two phases, gamma-prime and NiAl, for essentially all conditions, where gamma-prime was usually found on the NiAl grain boundaries. The stress-strain behavior of all three intermetallics was similar where flow at a nominally constant stress occurred after about two-percent plastic deformation. Furthermore, the 1000 to 1300 K flow stress-strain rate properties are nearly identical for these materials, and they are much lower than those for XD processed Ni-50Al. The overall deformation of the two phase nickel aluminides appears to be controlled by dislocation climb in NiAl rather than processes in gamma-prime.

Interfacial layers in high-temperature-oxidized NiCrAl

NASA Technical Reports Server (NTRS)

Larson, L. A.; Browning, R.; Poppa, H.; Smialek, J.

1983-01-01

The utility of Auger electron spectroscopy combined with ball cratering for depth analysis of oxide and diffusion layers produced in a Ni-14Cr-24Al alloy by oxidation in air at 1180 C for 25 hr is demonstrated. During postoxidation cooling, the oxide layers formed by this alloy spalled profusely. The remaining very thin oxide was primarily Cr2O3 with a trace of Ni. The underlying metal substrate exhibited gamma/gamma-prime and beta phases with a metallic interfacial layer which was similar to the bulk gamma/gamma-prime phase but slightly enriched in Cr and Al. These data are compared to electron microprobe results from a nominally identical alloy. The diffusion layer thickness is modelled with a simple mass balance equation and compared to recent results on the diffusion process in NiCrAl alloys.

Effect of swaging on the 1000 C compressive slow plastic flow characteristics of the directionally solidified eutectic alloy gamma/gamma prime-alpha

NASA Technical Reports Server (NTRS)

Whittenberger, J. D.; Wirth, G.

1983-01-01

Swaging between 750 and 1050 C has been investigated as a means to introduce work into the directionally solidified eutectic alloy gamma/gamma prime-alpha (Ni-32.3 wt percent Mo-6.3 wt percent Al) and increase the elevated temperature creep strength. The 1000 C slow plastic compressive flow stress-strain rate properties in air of as-grown, annealed, and worked nominally 10 and 25 percent materials have been determined. Swaging did not improve the slow plastic behavior. In fact large reductions tended to degrade the strength and produced a change in the deformation mechanism from uniform flow to one involving intense slip band formation. Comparison of 1000 C tensile and compressive strength-strain rate data reveals that deformation is independent of the stress state.

Refinement of Promising Coating Compositions for Directionally Cast Eutectics

NASA Technical Reports Server (NTRS)

Strangman, T. E.; Felten, E. J.; Benden, R. S.

1976-01-01

The successful application of high creep strength, directionally solidified gamma/gamma prime-delta (Ni-19.7Cb-6Cr-2.5Al) eutectic superalloy turbine blades requires the development of suitable coatings for airfoil, root and internal blade surfaces. In order to improve coatings for the gamma/gamma prime-delta alloy, the current investigation had the goals of (1) refining promising coating compositions for directionally solidified eutectics, (2) evaluating the effects of coating/ substrate interactions on the mechanical properties of the alloy, and (3) evaluating diffusion aluminide coatings for internal surfaces. Burner rig cyclic oxidation, furnace cyclic hot corrosion, ductility, and thermal fatigue tests indicated that NiCrAlY+Pt(63 to 127 micron Ni-18Cr-12Al-0.3Y + 6 micron Pt) and NiCrAlY(63 to 127 micron Ni-18Cr-12Al-0.3Y) coatings are capable of protecting high temperature gas path surfaces of eutectic alloy airfoils. Burner rig (Mach 0.37) testing indicated that the useful coating life of the 127 micron thick coatings exceeded 1000 hours at 1366 K (2000 deg F). Isothermal fatigue and furnance hot corrosion tests indicated that 63 micron NiCrAlY, NiCrAlY + Pt and platinum modified diffusion aluminide (Pt + Al) coating systems are capable of protecting the relatively cooler surfaces of the blade root. Finally, a gas phase coating process was evaluated for diffusion aluminizing internal surfaces and cooling holes of air-cooled gamma/gamma prime-delta turbine blades.

Alteration of sensitivity of intratumor quiescent and total cells to gamma-rays following thermal neutron irradiation with or without 10B-compound.

PubMed

Masunaga, S; Ono, K; Suzuki, M; Sakurai, Y; Kobayashi, T; Takagaki, M; Kinashi, Y; Akaboshi, M

2000-02-01

Changes in the sensitivity of intratumor quiescent (Q) and total cells to gamma-rays following thermal neutron irradiation with or without 10B-compound were examined. 5-Bromo-2'-deoxyuridine (BrdU) was injected to SCC VII tumor-bearing mice intraperitoneally 10 times to label all the proliferating (P) tumor cells. As priming irradiation, thermal neutrons alone or thermal neutrons with 10B-labeled sodium borocaptate (BSH) or dl-p-boronophenylalanine (BPA) were administered. The tumor-bearing mice then received a series of gamma-ray radiation doses, 0 through 24 h after the priming irradiation. During this period, no BrdU was administered. Immediately after the second irradiation, the tumors were excised, minced, and trypsinized. Following incubation of tumor cells with cytokinesis blocker, the micronucleus (MN) frequency in cells without BrdU labeling (= Q cells at the time of priming irradiation) was determined using immunofluorescence staining for BrdU. The MN frequency in the total (P + Q) tumor cells was determined from the tumors that were not pretreated with BrdU before the priming irradiation. To determine the BrdU-labeled cell ratios in the tumors at the time of the second irradiation, each group also included mice that were continuously administered BrdU until just before the second irradiation using mini-osmotic pumps which had been implanted subcutaneously 5 days before the priming irradiation. In total cells, during the interval between the two irradiations, the tumor sensitivity to gamma-rays relative to that immediately after priming irradiation decreased with the priming irradiation ranking in the following order: thermal neutrons only > thermal neutrons with BSH > thermal neutrons with BPA. In contrast, in Q cells, during that time the sensitivity increased in the following order: thermal neutrons only < thermal neutrons with BSH < thermal neutrons with BPA. The longer the interval between the two irradiations, the higher was the BrdU-labeled cell ratio at the second irradiation. The labeled cell ratio at the same time point after each priming irradiation increased in the following order: thermal neutrons only < thermal neutrons with BSH < thermal neutrons with BPA. These findings indicated that the use of 10B-compound, especially BPA, in thermal neutron irradiation causes the recruitment from the Q to P population.

NASA/ORNL/AFRL Project Work on EBM LSHR: Additive Manufacturing of High-Temperature Gamma-Prime Strengthened Ni-Based Superalloys

NASA Technical Reports Server (NTRS)

Sudbrack, Chantal K.; Kirka, Michael M.; Dehoff, Ryan R.; Carter, Robert W.; Semiatin, Sheldon L.; Gabb, Timothy P.

2016-01-01

Powder-bed fabrication of aerospace alloys may revolutionize production by eliminating the need for extensive machining and expensive tooling. Heated-bed electron-beam melting (EBM) offers advantages over non-heated laser additive manufacturing (AM) methods, including lower residual stress, reduced risk of contamination, slower cooling rates, and faster build times. NASA Glenn Research Center has joint project work with Oak Ridge National Lab and the Air Force Research Laboratory to explore the feasibility of fabricating advanced Ni-based gamma-prime superalloys with EBM AM.

Multi-Wavelength Observations of the Soft Gamma Repeater SGR 1900+14 During its April 2001 Activation

NASA Technical Reports Server (NTRS)

Kouveliotou, C.; Tennant, A. F.; Woods, P.; Hurley, K.; Fender, R. P.; Garrington, S. T.; Patel, S. K.; Gogus, E.; Whitaker, Ann F. (Technical Monitor)

2001-01-01

The soft-gamma repeater SGR became active on 18 April 2001 after about a year of quiescence; it had remained at a very low state of activity since the fall of 1998, when it exhibited extraordinary flaring. We have observed the source in the gamma and X-rays with \\ulysses and \\chandra, and in the radio with MERLIN. We report here the confirmation of a two component X-ray spectrum (power law $+$ blackbody), indicating emission from the neutron star surface. We have determined that there is a dust halo surrounding the source that extends up to $\\gtrsim100^{\\prime\\prime}$ from the SGR center, which is due to the scattering in the Interstellar Medium.

Effect of priming/booster immunisation protocols on immune response to canine parvovirus peptide induced by vaccination with a chimaeric plant virus construct.

PubMed

Nicholas, B L; Brennan, F R; Hamilton, W D O; Wakelin, D

2003-06-02

Expression of a 17-mer peptide sequence from canine parvovirus expressed on cowpea mosaic virus (CPMV) to form chimaeric virus particles (CVPs) creates vaccine antigens that elicit strong anti-peptide immune responses in mice. Systemic (subcutaneous, s.c.) immunisation and boosting with such CVP constructs produces IgG(2a) serum antibody responses, while mucosal (intranasal, i.n.) immunisation and boosting elicits intestinal IgA responses. Combinations of systemic and mucosal routes for priming and boosting immunisations were used to examine their influence on the level, type and location of immune response generated to one of these constructs (CVP-1). In all cases, s.c. administration, whether for immunisation or boosting, generated a Th1-biased response, reflected in a predominantly IgG(2a) serum antibody isotype and secretion of IFN-gamma from in vitro-stimulated lymphocytes. Serum antibody responses were greatest in animals primed and boosted subcutaneously, and least in mucosally vaccinated mice. The i.n. exposure also led to IFN-gamma release from in vitro-stimulated cells, but serum IgG(2a) was significantly elevated only in mice primed intranasally and boosted subcutaneously. Peptide- and wild-type CPMV-specific IgA responses in gut lavage fluid were greatest in animals exposed mucosally and least in those primed and boosted subcutaneously or primed subcutaneously and boosted orally. Lymphocytes from immunised mice proliferated in response to in vitro stimulation with CPMV but not with peptide. The predominant secretion of IFN-gamma from all immunising/boosting combinations indicates that the route of vaccination and challenge does not alter the Th1 bias of the response to CVP constructs. However, optimal serum and intestinal antibody responses were achieved by combining s.c. and i.n. administration.

Commensal oral bacteria antigens prime human dendritic cells to induce Th1, Th2 or Treg differentiation.

PubMed

Kopitar, A N; Ihan Hren, N; Ihan, A

2006-02-01

In various immunopathologic conditions, bacterial flora induce an immune response which results in inflammatory manifestations, e.g. periapical granuloma. Dendritic cells provide the main orchestration of specific immune responses. The aim of our study was to test the capacity of distinct oral bacterial antigens (prepared from Streptococcus mitis, Propionibacterium acnes, and Bacteroides spp.) to prime human dendritic cells for stimulation of the T-lymphocyte response. To assess the T-lymphocyte response, the expression of CD25, CD69, intracellular interferon gamma (cIFN-gamma), and intracellular interleukin 4 (cIL-4) was determined. Dendritic cells were prepared from leukocyte buffy coat from healthy blood donors. Monocytes were stimulated with IL-4 and GM-CSF and dendritic cells activated with bacterial lysates. Cell suspensions contained up to 90% dendritic cells, which represented 2-12% of the initial number of mononuclear cells. Lymphocyte subsets that developed in lymphocyte cultures after 1 week of stimulation were analyzed by flow cytometry. Dendritic cells, primed with antigens of Bacteroides fragilis have shown significantly higher activation and expression of intercellular IFN-gamma by T lymphocytes compared to negative controls. The dendritic cells primed with antigens of P. acnes had no effect on T-lymphocyte activation or cytokine production; instead they induced differentiation of T lymphocytes into CD25bright cells (regulatory T cells) with a potentially inhibitory effect on immune response. Dendritic cells primed with antigens of S. mitis induced increased expression of cIL-4. We conclude that commensal oral bacteria antigens prepared from B. fragilis, S. mitis, and P. acnes prime human dendritic cells to induce Th1, Th2, and T(reg) differentiation, respectively. This may advance our understanding of immunopathologic manifestations in the oral cavity and offer new possibilities for redirecting immune responses in mucosal vaccination.

Plastic Flow and Microstructure Evolution during Thermomechanical Processing of a PM Nickel-Base Superalloy

NASA Astrophysics Data System (ADS)

Semiatin, S. L.; McClary, K. E.; Rollett, A. D.; Roberts, C. G.; Payton, E. J.; Zhang, F.; Gabb, T. P.

2013-06-01

Plastic flow and microstructure evolution during sub- and supersolvus forging and subsequent supersolvus heat treatment of the powder-metallurgy superalloy LSHR (low-solvus, high-refractory) were investigated to develop an understanding of methods that can be used to obtain a moderately coarse gamma grain size under well-controlled conditions. To this end, isothermal, hot compression tests were conducted over broad ranges of temperature [(1144 K to 1450 K) 871 °C to 1177 °C] and constant true strain rate (0.0005 to 10 s-1). At low temperatures, deformation was generally characterized by flow softening and dynamic recrystallization that led to a decrease in grain size. At high subsolvus temperatures and low strain rates, steady-state flow or flow hardening was observed. These latter behaviors were ascribed to superplastic deformation and microstructure evolution characterized by a constant grain size or concomitant dynamic grain growth, respectively. During supersolvus heat treatment following subsolvus deformation, increases in grain size whose magnitude was a function of the prior deformation conditions were noted. A transition in flow behavior from superplastic to nonsuperplastic and the development during forging at a high subsolvus temperature of a wide (possibly bi- or multimodal) gamma-grain-size distribution having some large grains led to a substantially coarser grain size during supersolvus annealing in comparison to that produced under all other forging conditions.

Influence of molybdenum on the creep properties of nickel-base superalloy single crystals

NASA Technical Reports Server (NTRS)

Mackay, R. A.; Nathal, M. V.; Pearson, D. D.

1990-01-01

The Mo content of an alloy series based on Ni-6 wt pct Al-6 wt pct Ta was systematically varied from 9.8 to 14.6 wt pct, in order to ascertain the influence of Mo on the creep properties of single crystals. The optimum initial gamma-gamma prime microstructure for raft development and creep strength was established in each alloy before testing. It was found that, as the Mo content increased from 9.8 to 14.0 percent, the magnitude of the lattice mismatch increased; upon reaching 14.6 percent, a degradation of mechanical properties occurred due to the precipitation of a third phase. These results suggest that small refractory metal content and initial gamma-prime variations can profoundly affect mechanical properties.

Gamma prime hardened nickel-iron based superalloy

DOEpatents

Korenko, Michael K.

1978-01-01

A low swelling, gamma prime hardened nickel-iron base superalloy useful for fast reactor duct and cladding applications is described having from about 7.0 to about 10.5 weight percent (wt%) chromium, from about 24 to about 35 wt% nickel, from about 1.7 to about 2.5 wt% titanium, from about 0.3 to about 1.0 wt% aluminum, from about 2.0 to about 3.3 wt% molybdenum, from about 0.05 to about 1.0 wt% silicon, from about 0.03 to about 0.06 wt% carbon, a maximum of about 2 wt% manganese, and the balance iron.

Heat treatment study 2

NASA Technical Reports Server (NTRS)

Workman, Gary L.

1990-01-01

The microstructural variations in nickel based superalloys that result from modifications in processing were examined. These superalloys include MAR-M246(HF) and PWA1480. Alternate heat treatments for equiaxed as-cast specimens were studied and a sample matrix of 42 variations in the heat treatments were processed, as well as different directional solidification parameters. Variation in temperature and times for both solution and aging were performed. Photomicrographs were made of the microstructure and volume fraction analysis of primary gamma-prime and aged gamma-prime precipitates were performed. The results of the heat treatment, cooling rate, and directional solidification experiments are discussed.

The oscillatory entrainment of virtual pitch perception

PubMed Central

Aksentijevic, Aleksandar; Northeast, Anthony; Canty, Daniel; Elliott, Mark A.

2013-01-01

Evidence suggests that synchronized brain oscillations in the low gamma range (around 33 Hz) are involved in the perceptual integration of harmonic complex tones. This process involves the binding of harmonic components into “harmonic templates” – neural structures responsible for pitch coding in the brain. We investigated the hypothesis that oscillatory harmonic binding promotes a change in pitch perception style from spectral (frequency) to virtual (relational). Using oscillatory priming we asked 24 participants to judge as rapidly as possible, the direction of an ambiguous target with ascending spectral and descending virtual contour. They made significantly more virtual responses when primed at 29, 31, and 33 Hz and when the first target tone was harmonically related to the prime, suggesting that neural synchronization in the low gamma range could facilitate a shift toward virtual pitch processing. PMID:23630515

Role of Gamma-Band Synchronization in Priming of Form Discrimination for Multiobject Displays

ERIC Educational Resources Information Center

Lu, Hongjing; Morrison, Robert G.; Hummel, John E.; Holyoak, Keith J.

2006-01-01

Previous research has shown that synchronized flicker can facilitate detection of a single Kanizsa square. The present study investigated the role of temporally structured priming in discrimination tasks involving perceptual relations between multiple Kanizsa-type figures. Results indicate that visual information presented as temporally structured…

Eutectic superalloys strengthened by sigma, Ni3CB lamellae and gamma prime, Ni3Al precipitates

NASA Technical Reports Server (NTRS)

Lemkey, F. D.

1973-01-01

By means of a screening and solidification optimization study of certain alloys located on the gamma-sigma liquidus surface within the Ni-Cb-Cr-Al system, alloys with high temperature properties superior to those of all known superalloys were defined. One alloy, Ni - 19.7w/o Cb - 6.0w/o Cr - 2.5w/o Al, directionally solidified at 3 cm/hr met or exceeded each program goal. A second alloy, Ni-21.75 w/o Cb-2.55 w/o Al, although deficient in its inherent oxidation resistance, met the other program goals and combined a remarkable insensitivity of composite microstructure to solidification parameters with excellent low temperature toughness. This investigation demonstrated that useful properties for gas turbine airfoil application have been achieved by reinforcing a strong and tough gamma solid solution matrix containing precipitated gamma prime by a lamellar intermetallic compound Ni3 Cb having greater strength at elevated temperature.

Feasibility study of tungsten as a diffusion barrier between nickel-chromium-aluminum and Gamma/Gamma prime - Delta eutectic alloys

NASA Technical Reports Server (NTRS)

Young, S. G.; Zellars, G. R.

1978-01-01

Coating systems proposed for potential use on eutectic alloy components in high-temperature gas turbine engines were studied with emphasis on deterioration of such systems by diffusion. A 1-mil thick W sheet was placed between eutectic alloys and a NiCrAl layer. Layered test specimens were aged at 1100 C for as long as long as 500 hours. Without the W barrier, the delta phase of the eutectic deteriorated by diffusion of Nb into the NiCrAl. Insertion of the W barrier stopped the diffusion of Nb from delta. Chromium diffusion from the NiCrAl into the gamma/gamma prime phase of the eutectic was greatly reduced by the barrier. However, the barrier thickness decreased with time; and W diffused into both the NiCrAl and the eutectic. When the delta platelets were alined parallel to the NiCrAl layer, rather than perpendicular, diffusion into the eutectic was reduced.

Atom Probe Tomography Analysis of the Distribution of Rhenium in Nickel Alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mottura, A.; Warnken, N; Miller, Michael K

2010-01-01

Atom probe tomography (APT) is used to characterise the distributions of rhenium in a binary Ni-Re alloy and the nickel-based single-crystal CMSX-4 superalloy. A purpose-built algorithm is developed to quantify the size distribution of solute clusters, and applied to the APT datasets to critique the hypothesis that rhenium is prone to the formation of clusters in these systems. No evidence is found to indicate that rhenium forms solute clusters above the level expected from random fluctuations. In CMSX-4, enrichment of Re is detected in the matrix phase close to the matrix/precipitate ({gamma}/{gamma}{prime}) phase boundaries. Phase field modelling indicates that thismore » is due to the migration of the {gamma}/{gamma}{prime} interface during cooling from the temperature of operation. Thus, neither clustering of rhenium nor interface enrichments can be the cause of the enhancement in high temperature mechanical properties conferred by rhenium alloying.« less

Photon beam asymmetry Σ for η and η' photoproduction from the proton

DOE PAGES

Collins, P.; Ritchie, B. G.; Dugger, M.; ...

2017-05-18

Measurements of the linearly-polarized photon beam asymmetrymore » $$\\Sigma$$ for photoproduction from the proton of $$\\eta$$ and $$\\eta^\\prime$$ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the $$\\gamma p \\to \\eta p$$ reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the $$\\gamma p \\to \\eta^\\prime p$$ reaction. For $$\\gamma p \\to \\eta p$$, the data reported here considerably extend the range of measurements to higher energies, and are consistent with the few previously published measurements for this observable near threshold. For $$\\gamma p \\to \\eta^\\prime p$$, the results obtained are consistent with the few previously published measurements for this observable near threshold, but also greatly expand the incident photon energy coverage for that reaction. In conclusion, initial analysis of the data reported here with the Bonn-Gatchina model strengthens the evidence for four nucleon resonances -- the $N(1895)1/2^-$, $N(1900)3/2^+$, $N(2100)1/2^+$ and $N(2120)3/2^-$ resonances -- which presently lack the "four-star" status in the current Particle Data Group compilation, providing examples of how these new measurements help refine models of the photoproduction process.« less

Photon beam asymmetry Σ for η and η' photoproduction from the proton

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins, P.; Ritchie, B. G.; Dugger, M.

Measurements of the linearly-polarized photon beam asymmetrymore » $$\\Sigma$$ for photoproduction from the proton of $$\\eta$$ and $$\\eta^\\prime$$ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the $$\\gamma p \\to \\eta p$$ reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the $$\\gamma p \\to \\eta^\\prime p$$ reaction. For $$\\gamma p \\to \\eta p$$, the data reported here considerably extend the range of measurements to higher energies, and are consistent with the few previously published measurements for this observable near threshold. For $$\\gamma p \\to \\eta^\\prime p$$, the results obtained are consistent with the few previously published measurements for this observable near threshold, but also greatly expand the incident photon energy coverage for that reaction. In conclusion, initial analysis of the data reported here with the Bonn-Gatchina model strengthens the evidence for four nucleon resonances -- the $N(1895)1/2^-$, $N(1900)3/2^+$, $N(2100)1/2^+$ and $N(2120)3/2^-$ resonances -- which presently lack the "four-star" status in the current Particle Data Group compilation, providing examples of how these new measurements help refine models of the photoproduction process.« less

N * → Nη ' decays from photoproduction of η ' -mesons off protons

DOE PAGES

Anisovich, A. V.; Burkert, V.; Collins, P. M.; ...

2017-06-27

We presented a study of the partial-wave content of themore » $$\\gamma p\\to \\eta^\\prime p$$ reaction in the fourth resonance region, which has been prompted by new measurements of polarization observables for that process. Using the Bonn-Gatchina partial-wave formalism, the incorporation of new data indicates that the $N(1895)1/2^-$, $N(1900)3/2^+$, $N(2100)1/2^+$, and $N(2120)3/2^-$ are the most significant contributors to the photoproduction process. Some new results for the branching ratios of the decays of these more prominent resonances to $$N\\eta^\\prime$$ final states are provided; such branches have not been indicated in the most recent edition of the Review of Particle Properties. Based on the analysis performed here, predictions for the helicity asymmetry $E$ for the $$\\gamma p\\to \\eta^\\prime p$$ reaction are presented.« less

Process of welding gamma prime-strengthened nickel-base superalloys

DOEpatents

Speigel, Lyle B.; White, Raymond Alan; Murphy, John Thomas; Nowak, Daniel Anthony

2003-11-25

A process for welding superalloys, and particularly articles formed of gamma prime-strengthened nickel-base superalloys whose chemistries and/or microstructures differ. The process entails forming the faying surface of at least one of the articles to have a cladding layer of a filler material. The filler material may have a composition that is different from both of the articles, or the same as one of the articles. The cladding layer is machined to promote mating of the faying surfaces, after which the faying surfaces are mated and the articles welded together. After cooling, the welded assembly is free of thermally-induced cracks.

Heat Treatment Devices and Method of Operation Thereof to Produce Dual Microstructure Superalloys Disks

NASA Technical Reports Server (NTRS)

Gayda, John (Inventor); Gabb, Timothy P. (Inventor); Kantzos, Peter T. (Inventor)

2003-01-01

A heat treatment assembly and heat treatment methods are disclosed for producing different microstructures in the bore and rim portions of nickel-based superalloy disks, particu- larly suited for gas turbine applications. The heat treatment assembly is capable of being removed from the furnace and disassembled to allow rapid fan or oil quenching of the disk. For solutioning heat treatments of the disk, temperatures higher than that of this solvus temperature of the disk are used to produce coarse grains in the rim of each disk so as to give maximum creep and dwell crack resistance at the rim service temperature. At the same time, solution temperature lower than the solvus temperature of the disk are provided to produce fine grain in the bore of the disk so as to give maximum strength and low cycle fatigue resistance.

High temperature cyclic oxidation data. Part 1: Turbine alloys

NASA Technical Reports Server (NTRS)

Barrett, Charles A.; Garlick, Ralph G.; Lowell, Carl E.

1989-01-01

Specific-weight-change-versus-time data and x ray diffraction results are presented derived from high temperature cyclic tests on high temperature, high strength nickel-base gamma/gamma prime and cobalt-base turbine alloys. Each page of data summarizes a complete test on a given alloy sample.

Priming-boosting vaccination with recombinant Mycobacterium bovis bacillus Calmette-Guérin and a nonreplicating vaccinia virus recombinant leads to long-lasting and effective immunity.

PubMed

Ami, Yasushi; Izumi, Yasuyuki; Matsuo, Kazuhiro; Someya, Kenji; Kanekiyo, Masaru; Horibata, Shigeo; Yoshino, Naoto; Sakai, Koji; Shinohara, Katsuaki; Matsumoto, Sohkichi; Yamada, Takeshi; Yamazaki, Shudo; Yamamoto, Naoki; Honda, Mitsuo

2005-10-01

Virus-specific T-cell responses can limit immunodeficiency virus type 1 (HIV-1) transmission and prevent disease progression and so could serve as the basis for an affordable, safe, and effective vaccine in humans. To assess their potential for a vaccine, we used Mycobacterium bovis bacillus Calmette-Guérin (BCG)-Tokyo and a replication-deficient vaccinia virus strain (DIs) as vectors to express full-length gag from simian immunodeficiency viruses (SIVs) (rBCG-SIVgag and rDIsSIVgag). Cynomolgus macaques were vaccinated with either rBCG-SIVgag dermally as a single modality or in combination with rDIsSIVgag intravenously. When cynomologus macaques were primed with rBCG-SIVgag and then boosted with rDIsSIVgag, high levels of gamma interferon (IFN-gamma) spot-forming cells specific for SIV Gag were induced. This combination regimen elicited effective protective immunity against mucosal challenge with pathogenic simian-human immunodeficiency virus for the 1 year the macaques were under observation. Antigen-specific intracellular IFN-gamma activity was similarly induced in each of the macaques with the priming-boosting regimen. Other groups receiving the opposite combination or the single-modality vaccines were not effectively protected. These results suggest that a recombinant M. bovis BCG-based vector may have potential as an HIV/AIDS vaccine when administered in combination with a replication-deficient vaccinia virus DIs vector in a priming-boosting strategy.

Microstructural changes caused by thermal treatment and their effects on mechanical properties of a gamma/gamma prime - delta eutectic alloy

NASA Technical Reports Server (NTRS)

Tewari, S. N.; Dreshfield, R. L.

1976-01-01

Microstructural changes due to thermal treatments of a directionally solidified gamma/gamma'-delta eutectic alloy were investigated. Aging treatments of 8 to 48 hours and ranging from 750 to 1120 C were given to the alloy in both its as directionally solidified condition and after gamma' solutioning. Aging resulted in gamma' coarsening gamma precipitates in delta, and delta and gamma'' precipitates in delta. The tensile strength was increased about 12 percent at temperatures up to 900 C by a heat treatment. Times to rupture were essentially the same or greater than for as directionally solidified material. Tensile and rupture ductility in the growth direction of the alloy were reduced by the heat treatment.

Observations of directional gamma prime coarsening during engine operation

NASA Technical Reports Server (NTRS)

Draper, Susan L.; Hull, David R.; Dreshfield, Robert L.

1987-01-01

Two alloys with negative mismatch parameters, NASAIR 100 and a modified NASAIR 100 called Alloy 3 were run as turbine blades in an experimental ground based Garret TFE731 engine for up to 200 hr. The directional coarsening of gamma prime (rafting) that developed during engine testing was analyzed and compared to previous research from laboratory tests. The blades were found to be rafted normal to the centrifugal stress axis over much of the span, but near the surfaces, the blades were found to be rafted parallel to the centrifugal stress axis for certain cycles. Representative photomicrographs of the blades and the effects of stress and temperature on raft formation are shown.

Observations of directional gamma prime coarsening during engine operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Draper, S.L.; Hull, D.R.; Dreshfield, R.L.

1987-02-01

Two alloys with negative mismatch parameters, NASAIR 100 and a modified NASAIR 100 called Alloy 3 were run as turbine blades in an experimental ground based Garret TFE731 engine for up to 200 hr. The directional coarsening of gamma prime (rafting) that developed during engine testing was analyzed and compared to previous research from laboratory tests. The blades were found to be rafted normal to the centrifugal stress axis over much of the span, but near the surfaces, the blades were found to be rafted parallel to the centrifugal stress axis for certain cycles. Representative photomicrographs of the blades andmore » the effects of stress and temperature on raft formation are shown.« less

Observations of directional gamma prime coarsening during engine operation

NASA Technical Reports Server (NTRS)

Draper, S.; Hull, D.; Dreshfield, R.

1989-01-01

Two alloys, NASAIR 100 and a modified NASAIR 100 called Alloy 3, were run as turbine blades in an experimental ground-based Garrett TFE731 engine for up to 200 hours. The stress induced directional coarsening of gamma-prime (rafting) that developed during engine testing was analyzed and compared to previous research from laboratory tests. The blades were found to have formed a lamellar structure, the lamellae being normal to the centrifugal stress axis over much of the span. However, near the surfaces, the blades were found to have formed lamellae parallel to the centrifugal stress axis for certain cycles. Representative photomicrographs of the blades and the effects of stress and temperature on lamellae formation are shown.

Experimental reinfection of BALB/c mice with different recombinant type I/III strains of Toxoplasma gondii: involvement of IFN-gamma and IL-10.

PubMed

Brandão, Geane Peroni; Melo, Maria Norma; Gazzinelli, Ricardo Tostes; Caetano, Braulia Costa; Ferreira, Adriana Melo; Silva, Letícia Azevedo; Vitor, Ricardo Wagner Almeida

2009-03-01

To assess reinfection of BALB/c mice with different Toxoplasma gondii strains, the animals were prime infected with the non-virulent D8 strain and challenged with virulent recombinant strains. Thirty days after challenge, brain cysts were obtained from surviving BALB/c mice and inoculated in Swiss mice to obtain tachyzoites for DNA extraction and PCR-RFLP analysis to distinguish the different T. gondii strains present in possible co-infections. Anti-Toxoplasma immune responses were evaluated in D8-primed BALB/c mice by detecting IFN-gamma and IL-10 produced by T cells and measuring immunoglobulin levels in serum samples. PCR-RFLP demonstrated that BALB/c mice were reinfected with the EGS strain at 45 days post prime infection (dpi) and with the EGS and CH3 strains at 180 dpi. High levels of IFN-gamma were detected after D8 infection, with no significant difference between 45 and 180-day intervals. However, higher IL-10 levels and higher plasmatic IgG1 and IgA were detected from samples obtained 180 days after infection. BALB/c mice were susceptible to reinfection with different recombinant T. gondii strains and this susceptibility correlated with enhancement of IL-10 production.

High temperature deformation mechanisms of L12-containing Co-based superalloys

NASA Astrophysics Data System (ADS)

Titus, Michael Shaw

Ni-based superalloys have been used as the structural material of choice for high temperature applications in gas turbine engines since the 1940s, but their operating temperature is becoming limited by their melting temperature (Tm =1300degrees C). Despite decades of research, no viable alternatives to Ni-based superalloys have been discovered and developed. However, in 2006, a ternary gamma' phase was discovered in the Co-Al-W system that enabled a new class of Co-based superalloys to be developed. These new Co-based superalloys possess a gamma-gamma' microstructure that is nearly identical to Ni-based superalloys, which enables these superalloys to achieve extraordinary high temperature mechanical properties. Furthermore, Co-based alloys possess the added benefit of exhibiting a melting temperature of at least 100degrees C higher than commercial Ni-based superalloys. Superalloys used as the structural materials in high pressure turbine blades must withstand large thermomechanical stresses imparted from the rotating disk and hot, corrosive gases present. These stresses induce time-dependent plastic deformation, which is commonly known as creep, and new superalloys must possess adequate creep resistance over a broad range of temperature in order to be used as the structural materials for high pressure turbine blades. For these reasons, this research focuses on quantifying high temperature creep properties of new gamma'-containing Co-based superalloys and identifying the high temperature creep deformation mechanisms. The high temperature creep properties of new Co- and CoNi-based alloys were found to be comparable to Ni-based superalloys with respect to minimum creep rates and creep-rupture lives at 900degrees C up to the solvus temperature of the gamma' phase. Co-based alloys exhibited a propensity for extended superlattice stacking fault formation in the gamma' precipitates resulting from dislocation shearing events. When Ni was added to the Co-based compositions, this mode of shearing altered such that extended antiphase boundaries formed in the gamma' precipitates. These high temperature shearing mechanisms differ from Ni-based superalloys, where shearing occurs via APB-coupled dislocations. High resolution electron microscopy studies revealed chemical fluctuations of solute near stacking faults and antiphase boundaries in the gamma' phases. These chemical fluctuations were found to significantly reduce the stacking fault energy, which was calculated via first-principles. The implications for these chemical fluctuations on creep strength were determined, and new models for precipitate shearing will be presented. Furthermore, the implications for the design of new Co- and CoNi-based compositions will be discussed.

Age-related T cell responses to allergens in childhood.

PubMed

Smart, J M; Suphioglu, C; Kemp, A S

2003-03-01

T cell priming, as determined by allergen-induced proliferative responses, is believed to occur principally in early childhood in both atopic and non-atopic infants under the influence of multiple factors including environmental allergen exposure. It is considered that T cell priming with expansion of Th2 cells is a crucial factor in the development of atopic disease. To examine T cell priming to commonly encountered allergens in childhood in relation to age. In a cross-sectional study T cell proliferation in relation to age was examined for three common allergens, ovalbumin (OVA), house dust mite (HDM) and rye grass pollen (RYE), in atopic and non-atopic children. The effect of age on Th1 (IFN-gamma) and Th2 (IL-5 and IL-13) cytokine production in response to these allergens was investigated to examine the possibility of immune deviation with time. A significant increase in T cell proliferation with age was observed with RYE among atopic children only. However, the same was not observed with the two other allergens studied (i.e. OVA and HDM). In addition, RYE-induced (but not HDM or OVA) cytokine production showed an increased Th2 deviation with age as reflected in the increasing IL-5/IFN-gamma and IL-13/IFN-gamma ratios only among the atopic subjects with rye grass pollen sensitivity. These findings suggest that grass pollen sensitivity in childhood is accompanied by a progressive accumulation of allergen-primed T cells and progressive deviation of the allergen-induced cytokine response towards a Th2 response in atopic subjects throughout childhood.

Ir gene controlled carrier effects in the induction and elicitation of hapten-specific delayed-type hypersensitivity responses.

PubMed

Weinberger, J Z; Benacerraf, B; Dorf, M E

1979-11-01

The genetic requirements of carrier recognition were examined in the priming and elicitation of hapten specific, T-cell mediated, delayed-type hypersensitivity (DTH) responses. It was shown that nitrophenyl acetyl-poly-(L-glu56-L-lys35-L-phe9) (NP-GLO) could prime for NP responses only in strains of mice which are Ir gene responders to GLO. In contrast to this requirement, NO-GLO could elicit an NP-specific response in NP-bovine gamma globulin primed mice, even in GLO nonresponder strains. Furthermore, the nonimmunogenic molecule, NP-GL, could elicit an NP-specific DTH response in animals primed with NP on an immunogenic carrier.

Effect of temperature, microstructure, and stress state on the low cycle fatigue behavior of Waspaloy

NASA Technical Reports Server (NTRS)

Stahl, D. R.; Antolovich, S. D.; Mirdamadi, M.; Zamrik, S. Y.

1988-01-01

Specimens of Waspaloy of two different microstructures were tested in uniaxial and torsional low-cycle fatigue at 24 and 649 C. For all specimens, deformation and failure mechanisms are found to be independent of stress state at 24 C; in both microstructures, failure is associated with the formation of shear cracks. At 649 C, deformation and failure mechanisms for the fine-grain large gamma-prime specimens are independent of stress state, and the mechanisms are similar to those observed at 24 C. For the coarse-grain small gamma-prime specimens, however, failure occurs on principal planes in torsion and on shear plane in uniaxial tension. The results are interpreted in terms of deformation mode and microstructural instability.

Characterization of Plastic Flow Pertinent to the Evolution of Bulk Residual Stress in Powder-Metallurgy, Nickel-Base Superalloys

NASA Astrophysics Data System (ADS)

Semiatin, S. L.; Fagin, P. N.; Goetz, R. L.; Furrer, D. U.; Dutton, R. E.

2015-09-01

The plastic-flow behavior which controls the formation of bulk residual stresses during final heat treatment of powder-metallurgy (PM), nickel-base superalloys was quantified using conventional (isothermal) stress-relaxation (SR) tests and a novel approach which simulates concurrent temperature and strain transients during cooling following solution treatment. The concurrent cooling/straining test involves characterization of the thermal compliance of the test sample. In turn, this information is used to program the ram-displacement- vs-time profile to impose a constant plastic strain rate during cooling. To demonstrate the efficacy of the new approach, SR tests (in both tension and compression) and concurrent cooling/tension-straining experiments were performed on two PM superalloys, LSHR and IN-100. The isothermal SR experiments were conducted at a series of temperatures between 1144 K and 1436 K (871 °C and 1163 °C) on samples that had been supersolvus solution treated and cooled slowly or rapidly to produce starting microstructures comprising coarse gamma grains and coarse or fine secondary gamma-prime precipitates, respectively. The concurrent cooling/straining tests comprised supersolvus solution treatment and various combinations of subsequent cooling rate and plastic strain rate. Comparison of flow-stress data from the SR and concurrent cooling/straining tests showed some similarities and some differences which were explained in the context of the size of the gamma-prime precipitates and the evolution of dislocation substructure. The magnitude of the effect of concurrent deformation during cooling on gamma-prime precipitation was also quantified experimentally and theoretically.

Nickel Base Superalloy Turbine Disk

NASA Technical Reports Server (NTRS)

Gabb, Timothy P. (Inventor); Gauda, John (Inventor); Telesman, Ignacy (Inventor); Kantzos, Pete T. (Inventor)

2005-01-01

A low solvus, high refractory alloy having unusually versatile processing mechanical property capabilities for advanced disks and rotors in gas turbine engines. The nickel base superalloy has a composition consisting essentially of, in weight percent, 3.0-4.0 N, 0.02-0.04 B, 0.02-0.05 C, 12.0-14.0 Cr, 19.0-22.0 Co, 2.0-3.5 Mo, greater than 1.0 to 2.1 Nb, 1.3 to 2.1 Ta,3.04.OTi,4.1 to 5.0 W, 0.03-0.06 Zr, and balance essentially Ni and incidental impurities. The superalloy combines ease of processing with high temperature capabilities to be suitable for use in various turbine engine disk, impeller, and shaft applications. The Co and Cr levels of the superalloy can provide low solvus temperature for high processing versatility. The W, Mo, Ta, and Nb refractory element levels of the superalloy can provide sustained strength, creep, and dwell crack growth resistance at high temperatures.

Chemiluminescence of nitric oxide

NASA Technical Reports Server (NTRS)

Sharp, W. E.; Rusch, D. W.

1981-01-01

Measurements of the intensities of the delta and gamma bands of nitric oxide in the nighttime terrestrial thermosphere are presented and used to infer the rate coefficient for the transition from the C 2 Pi to the A 2 Sigma + states. The nightglow spectrum was observed between 1900 and 2300 A at a resolution of 15 A by a rocket-borne scanning 1/4-m spectrometer pointing north at an apogee of 150 km. Progressions of the delta, gamma and epsilon bands are identified on the spectra by the construction of synthetic spectra, and the contributions of resonance fluorescence to the total band intensities are calculated. Finally, the ratio of the sum of the gamma bands for v-prime = 0 to the sum of the delta bands for v-prime = 0 is used to derive a branching ratio of 0.21 + or - 0.04 to the A 2 Sigma + state, which yields a probability for the C-A transition of 5.6 + or - 1.5 x to the 6th/sec.

Numerical results on the transcendence of constants involving pi, e, and Euler's constant

NASA Technical Reports Server (NTRS)

Bailey, David H.

1988-01-01

The existence of simple polynomial equations (integer relations) for the constants e/pi, e + pi, log pi, gamma (Euler's constant), e exp gamma, gamma/e, gamma/pi, and log gamma is investigated by means of numerical computations. The recursive form of the Ferguson-Fourcade algorithm (Ferguson and Fourcade, 1979; Ferguson, 1986 and 1987) is implemented on the Cray-2 supercomputer at NASA Ames, applying multiprecision techniques similar to those described by Bailey (1988) except that FFTs are used instead of dual-prime-modulus transforms for multiplication. It is shown that none of the constants has an integer relation of degree eight or less with coefficients of Euclidean norm 10 to the 9th or less.

HIV-1 Gag p17 presented as virus-like particles on the E2 scaffold from Geobacillus stearothermophilus induces sustained humoral and cellular immune responses in the absence of IFN{gamma} production by CD4+ T cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caivano, Antonella; Doria-Rose, Nicole A.; Dept. of Molecular and Cell Biology, University of Washington, Seattle, WA 98124-6108

2010-11-25

We have constructed stable virus-like particles displaying the HIV-1 Gag(p17) protein as an N-terminal fusion with an engineered protein domain from the Geobacillus stearothermophilus pyruvate dehydrogenase subunit E2. Mice immunized with the Gag(p17)-E2 60-mer scaffold particles mounted a strong and sustained antibody response. Antibodies directed to Gag(p17) were boosted significantly with additional immunizations, while anti-E2 responses reached a plateau. The isotype of the induced antibodies was biased towards IgG1, and the E2-primed CD4+ T cells did not secrete IFN{gamma}. Using transgenic mouse model systems, we demonstrated that CD8+ T cells primed with E2 particles were able to exert lytic activitymore » and produce IFN{gamma}. These results show that the E2 scaffold represents a powerful vaccine delivery system for whole antigenic proteins or polyepitope engineered proteins, evoking antibody production and antigen specific CTL activity even in the absence of IFN{gamma}-producing CD4+ T cells.« less

Ursolic acid isolated from Uncaria rhynchophylla activates human dendritic cells via TLR2 and/or TLR4 and induces the production of IFN-gamma by CD4+ naïve T cells.

PubMed

Jung, Tae-Young; Pham, Thanh Nhan Nguyen; Umeyama, Akemi; Shoji, Noboru; Hashimoto, Toshihiro; Lee, Je-Jung; Takei, Masao

2010-09-25

Ursolic acid is triterpene isolated from Uncaria rhynchophylla and is a pharmacologically active substance. The induction of dendritic cell maturation is critical for the induction of Ag-specific T-lymphocyte response and may be essential for the development of human vaccine relying on T cell immunity. In this study, we investigated that the effect of Ursolic acid on the phenotypic and functional maturation of human monocyte-derived dendritic cells in vitro. Dendritic cells harvested on day 8 were examined using functional assay. The expression levels of CD1a, CD80, CD83, CD86, HLA-DR and CCR7 on Ursolic acid-primed dendritic cells was slightly enhanced. Ursolic acid dose-dependently enhanced the T cell stimulatory capacity in an allogeneic mixed lymphocyte reaction, as measured by T cell proliferation. The production of IL-12p70 induced by Ursolic acid-primed dendritic cells was inhibited by the anti-Toll-like receptor-2 (TLR2) mAb and anti-TLR4 mAb. Moreover, Ursolic acid-primed dendritic cells expressed levels of mRNA coding for both TLR2 and TLR4. The majority of cells produced considerable interferon-gamma (IFN-gamma), but also small amounts of interleukin (IL-4)-4. Ursolic acid-primed dendritic cells have an intermediate migratory capacity towards CCL19 and CCL21. These results suggest that Ursolic acid modulates human dendritic cells function in a fashion that favors Th1 polarization via the activation of IL-12p70 dependent on TLR2 and/or TLR4, and may be used on dendritic cells-based vaccines for cancer immunotherapy. 2010 Elsevier B.V. All rights reserved.

Creep Deformation of Allvac 718Plus

DOE PAGES

Hayes, Robert W.; Unocic, Raymond R.; Nasrollahzadeh, Maryam

2014-11-11

The creep deformation behavior of Allvac 718Plus was studied over the temperature range 650° to 732°C at initial applied stress levels ranging from 517 to 655 MPa. Over the entire experimental temperature stress regime this alloy exhibits Class M type creep behavior with all creep curves exhibiting a decelerating strain rate with strain or time throughout primary creep. However, unlike pure metals or simple solid solution alloys this gamma prime strengthened superalloy does not exhibit steady state creep. Rather, primary creep is instantly followed by a long duration of accelerating strain rate with strain or time. These creep characteristics aremore » common amongst the gamma prime strengthened superalloys. Allvac 718Plus also exhibits a very high temperature dependence of creep rate. Detailed TEM examination of the deformation structures of selected creep samples reveals dislocation mechanisms similar to those found in high volume fraction gamma prime strengthened superalloys. Strong evidence of microtwinning is found in several of the deformation structures. The presence of microtwinning may account for the strong temperature dependence of creep rate observed in this alloy. In addition, due to the presence of Nb and thus, grain boundary delta phase, matrix dislocation activity which is not present in non Nb bearing superalloys occurs in this alloy. The creep characteristics and dislocation mechanisms are presented and discussed in detail.« less

The effect of microstructure on 650 C fatigue crack growth in P/M Astroloy

NASA Technical Reports Server (NTRS)

Gayda, J.; Miner, R. V.

1983-01-01

The effect of microstructure on fatigue crack propagation at 650 C has been studied in a P/M nickel-base superalloy, Astroloy. Crack propagation data were obtained in air and vacuum at 20 cpm with a modified compact tension specimen. The rate of crack growth, da/dn, was correlated with the stress intensity range. Key microstructural variables examined were grain size and the distribution and size of the strengthening gamma prime phase. A fine grain size less than 20 microns always promoted rapid, intergranular failure, while a large grain size promoted slower, transgranular failure which decreased as the size and volume fraction of aging gamma prime was manipulated so as to increase alloy strength. The rapid, intergranular mode of failure of the fine grain microstructures was suppressed in vacuum.

Fundamental Investigation of the Microstructural Parameters to Improve Dynamic Response in Al-Cu Model System

DTIC Science & Technology

2014-05-01

grain size. Recrystallization was then induced via annealing just above the solvus temperature. After quenching , the bars were immediately placed into...that the values were statistically significant. Precipitate sizes ranged from approximately 100 nanometers in diameter up to 2-5 microns in diameter

Neutrophil hyper-responsiveness in periodontitis.

PubMed

Matthews, J B; Wright, H J; Roberts, A; Ling-Mountford, N; Cooper, P R; Chapple, I L C

2007-08-01

Peripheral neutrophil hyper-responsiveness in chronic periodontitis leads to excessive reactive oxygen species (ROS) production. We aimed to determine whether neutrophil hyper-responsiveness was constitutive or reactive, and to discover the effect of non-surgical therapy. Peripheral blood neutrophils from patients (n = 19), before and 3 months after therapy, and matched control individuals were Fc gamma-receptor-stimulated with/without priming with P. gingivalis and F. nucleatum. Total and extracellular ROS were determined by luminol/isoluminol chemiluminescence. The high total ROS generation of patients' neutrophils compared with that of control individuals (P = 0.016) continued at a reduced level post-therapy (P = 0.059). Reduced activity post-therapy was also seen with priming. Unstimulated total ROS levels did not differ between patients and control individuals before or after therapy. However, the high unstimulated, extracellular ROS production by patients' neutrophils compared with control individuals (P < 0.05) continued post-therapy and was unaffected by priming. Therapy reduced Fc gamma-receptor-stimulated total ROS production, but not unstimulated extracellular radical release, suggesting that constitutive and reactive mechanisms underlie neutrophil hyper-responsiveness.

Comparison of human and rhesus macaque T-cell responses elicited by boosting with NYVAC encoding human immunodeficiency virus type 1 clade C immunogens.

PubMed

Mooij, Petra; Balla-Jhagjhoorsingh, Sunita S; Beenhakker, Niels; van Haaften, Patricia; Baak, Ilona; Nieuwenhuis, Ivonne G; Heidari, Shirin; Wolf, Hans; Frachette, Marie-Joelle; Bieler, Kurt; Sheppard, Neil; Harari, Alexandre; Bart, Pierre-Alexandre; Liljeström, Peter; Wagner, Ralf; Pantaleo, Giuseppe; Heeney, Jonathan L

2009-06-01

Rhesus macaques (Macaca mulatta) have played a valuable role in the development of human immunodeficiency virus (HIV) vaccine candidates prior to human clinical trials. However, changes and/or improvements in immunogen quality in the good manufacturing practice (GMP) process or changes in adjuvants, schedule, route, dose, or readouts have compromised the direct comparison of T-cell responses between species. Here we report a comparative study in which T-cell responses from humans and macaques to HIV type 1 antigens (Gag, Pol, Nef, and Env) were induced by the same vaccine batches prepared under GMP and administered according to the same schedules in the absence and presence of priming. Priming with DNA (humans and macaques) or alphavirus (macaques) and boosting with NYVAC induced robust and broad antigen-specific responses, with highly similar Env-specific gamma interferon (IFN-gamma) enzyme-linked immunospot assay responses in rhesus monkeys and human volunteers. Persistent cytokine responses of antigen-specific CD4(+) and CD8(+) T cells of the central memory as well as the effector memory phenotype, capable of simultaneously eliciting multiple cytokines (IFN-gamma, interleukin 2, and tumor necrosis factor alpha), were induced. Responses were highly similar in humans and primates, confirming earlier data indicating that priming is essential for inducing robust NYVAC-boosted IFN-gamma T-cell responses. While significant similarities were observed in Env-specific responses in both species, differences were also observed with respect to responses to other HIV antigens. Future studies with other vaccines using identical lots, immunization schedules, and readouts will establish a broader data set of species similarities and differences with which increased confidence in predicting human responses may be achieved.

Evaluation of an advanced directionally solidified gamma/gamma'-alpha Mo eutectic alloy

NASA Technical Reports Server (NTRS)

Henry, M. F.; Jackson, M. R.; Gigliotti, M. F. X.; Nelson, P. B.

1979-01-01

An attempt was made to improve on the properties of the candidate jet engine turbine blade material AG-60, a gamma/gamma prime-alpha Mo eutectic composite. Alloy 38 (AG-170) was evaluated in the greatest detail. This alloy, Ni-5.88 A1-29.74 Mo-1.65 V-1.2C Re (weight percent), represents an improvement beyond AG-60, based on mechanical testing of the transverse and/or longitudinal orientations over a range of temperatures in tension, shear, rupture, and rupture after thermal exposure. It is likely that other alloys in the study represent a similar improvement.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lillo, Thomas Martin

During the first quarter of FY17, research has focused on: 1. Generation of synthetic microstructures of welds 2. Aging of gamma prime 3. Short term creep tests 4. Preparation for stress drop tests to determine the threshold stress.

Method for heat treating iron-nickel-chromium alloy

DOEpatents

Not Available

1980-04-03

A method is described for heat treating an age-hardenable iron-nickel-chromium alloy to obtain a morphology of the gamma-double prime phase enveloping the gamma-prime, the alloy consisting essentially of about 25 to 45% nickel, 10 to 16% chromium, 1.5 to 3% of an element selected from the group consisting of molybdenum and niobium, about 2% titanium, about 3% aluminum, and the remainder substantially all iron. To obtain optimum results, the alloy is heated to a temperature of 1025 to 1075/sup 0/C for 2 to 5 minutes, cold-worked about 20 to 60%, aged at a temperature of about 775/sup 0/C for 8 hours followed by an air-cool, and then heated to a temperature in the range of 650 to 700/sup 0/C for 2 hours followed by an air-cool.

Method for heat treating iron-nickel-chromium alloy

DOEpatents

Korenko, Michael K.

1980-01-01

A method for heat treating an age-hardenable iron-nickel-chromium alloy to obtain a morphology of the gamma-double prime phase enveloping the gamma-prime phase, the alloy consisting essentially of about 40 to 50% nickel, 7.5 to 14% chromium, 1.5 to 4% niobium, 0.3 to 0.75% silicon, 1 to 3% titanium, 0.1 to 0.5% aluminum, 0.02 to 1% carbon, 0.002 to 0.0015% boron and the remain substantially all iron. To obtain optimal results, the alloy is cold-worked 20 to 60% followed by heating at 1050.degree. C. for 1/2 hour with an air-cool plus heating at 800.degree. C. for 2 hours with a furnace cool to 625.degree. C. The alloy is then held at 625.degree. C. for 12 hours, followed by an air-cool.

The Microstructure and Gamma Prime Distributions in Inertia Friction Welded Joint of P/M Superalloy FGH96

NASA Astrophysics Data System (ADS)

Zhang, Chi; Shen, Wenfei; Zhang, Liwen; Xia, Yingnan; Li, Ruiqin

2017-04-01

A gamma prime ( γ') precipitation ( 35% in volume)-hardened powder metallurgy (P/M) superalloy FGH96 was welded using inertia friction welding (IFW). The microstructure and γ' distributions in the joints in two conditions, hot isostatic pressed state and solution-treated and aged state, were characterized. The recrystallization of grains, the dissolution and re-precipitation of γ' in the joints were discussed in terms of the temperature evolutions which were calculated by finite element model analysis. Regardless of the initial states, fully recrystallized fine grain structure formed at welded zone. Meanwhile, very fine γ' precipitations were re-precipitated at the welded zone. These recrystallized grain structure and fine re-precipitated γ' resulted in increasing hardness of IFW joint while making the hardness dependent on the microstructure and γ' precipitation.

Microstructure Modeling of Third Generation Disk Alloys

NASA Technical Reports Server (NTRS)

Jou, Herng-Jeng

2010-01-01

The objective of this program was to model, validate, and predict the precipitation microstructure evolution, using PrecipiCalc (QuesTek Innovations LLC) software, for 3rd generation Ni-based gas turbine disc superalloys during processing and service, with a set of logical and consistent experiments and characterizations. Furthermore, within this program, the originally research-oriented microstructure simulation tool was to be further improved and implemented to be a useful and user-friendly engineering tool. In this report, the key accomplishments achieved during the third year (2009) of the program are summarized. The activities of this year included: Further development of multistep precipitation simulation framework for gamma prime microstructure evolution during heat treatment; Calibration and validation of gamma prime microstructure modeling with supersolvus heat treated LSHR; Modeling of the microstructure evolution of the minor phases, particularly carbides, during isothermal aging, representing the long term microstructure stability during thermal exposure; and the implementation of software tools. During the research and development efforts to extend the precipitation microstructure modeling and prediction capability in this 3-year program, we identified a hurdle, related to slow gamma prime coarsening rate, with no satisfactory scientific explanation currently available. It is desirable to raise this issue to the Ni-based superalloys research community, with hope that in future there will be a mechanistic understanding and physics-based treatment to overcome the hurdle. In the mean time, an empirical correction factor was developed in this modeling effort to capture the experimental observations.

Borrelia-primed and -infected mice deficient of interleukin-17 develop arthritis after neutralization of gamma-interferon.

PubMed

Kuo, Joseph; Warner, Thomas F; Schell, Ronald F

2017-03-01

The immune mechanisms responsible for development of Lyme arthritis are partially understood with interleukin-17 (IL-17) and gamma-interferon (IFN-γ) playing a generally accepted role. Elevated levels of IL-17 and/or IFN-γ have been reported in samples from human Lyme arthritis patients and experimental mice. In addition, IL-17 and IFN-γ have been implicated in the onset of arthritis in Borrelia-primed and -infected C57BL/6 mice. Recently, we showed that IL-17-deficient mice developed swelling and histopathological changes consistent with arthritis in the presence of high levels of IFN-γ. We hypothesized that neutralization of IFN-γ in IL-17-deficient mice would inhibit Borrelia-induced arthritis. Our results, however, showed that swelling of the hind paws and histopathological changes of arthritis did not differ between Borrelia-primed and -infected IL-17-deficient and wild-type mice with or without neutralization of IFN-γ. We also found higher levels of tumor necrosis factor alpha (TNF-α) and IL-6 in the popliteal lymph node cells of Borrelia-primed and -infected IL-17-deficient mice after neutralization of IFN-γ. These results suggest that multiple cytokines interact in the development of Borrelia-induced arthritis. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Chromium and Tantalum Site Substitution Patterns in Ni3Al (L1(sub 2))gamma(prime)- Precipitates

NASA Technical Reports Server (NTRS)

Booth-Morrison, Christopher; Mao, Zugang; Seidman, David N.; Noebe, Ronald D.

2008-01-01

The site substitution behavior of Cr and Ta in the Ni3Al (Ll2)-type gamma'-precipitates of a Ni-Al-Cr-Ta alloy is investigated by atom-probe tomography (APT) and first-principles calculations. Measurements of the gamma'-phase composition by APT suggest that Al, Cr, and Ta share the Al sublattice sites of the gamma'-precipitates. The calculated substitutional energies of the solute atoms at the Ni and Al sublattice sites indicate that Ta has a strong preference for the Al sites, while Cr has a weak Al site preference. Furthermore, Ta is shown to replace Cr at the Al sublattice sites of the gamma'-precipitates, altering the elemental phase partitioning behavior of the Ni-Al-Cr-Ta alloy.

Optimizing the Hot-Corrosion Resistance-of-Novel gamma-Ni+gamma-prime-Ni3A1-Based Alloys and Coatings

DTIC Science & Technology

2006-07-01

TBC benefit Substrale limit 1 1 0 0 ---------- .- -.. . . . . . . --- I single crystal S1000 conventlonally cest allos . .- alloy. E directionally...usually heat treated or processed) forms. Developments in casting technologies made it possible to produce directionally-solidified and single - crystal ...advanced single - crystal superalloys with improved strength meant reductions in chromium and silicon contents. The scale growth and spallation rates can be

Microstructural Characterization and Modeling of SLM Superalloy 718

NASA Technical Reports Server (NTRS)

Smith, Tim M.; Sudbrack, Chantal K.; Bonacuse, Pete; Rogers, Richard

2017-01-01

Superalloy 718 is an excellent candidate for selective laser melting (SLM) fabrication due to a combination of excellent mechanical properties and workability. Predicting and validating the microstructure of SLM-fabricated Superalloy 718 after potential post heat-treatment paths is an important step towards producing components comparable to those made using conventional methods. At present, obtaining accurate volume fraction and size measurements of gamma-double-prime, gamma-prime and delta precipitates has been challenging due to their size, low volume fractions, and similar chemistries. A technique combining high resolution distortion corrected SEM imaging and with x-ray energy dispersive spectroscopy has been developed to accurately and independently measure the size and volume fractions of the three precipitates. These results were further validated using x-ray diffraction and phase extraction methods and compared to the precipitation kinetics predicted by PANDAT and JMatPro. Discrepancies are discussed in context of materials properties, model assumptions, sampling, and experimental errors.

Effects of chromium and aluminum on mechanical and oxidation properties of iron-nickel-base superalloys based on CG-27

NASA Technical Reports Server (NTRS)

Schuon, S. R.

1985-01-01

The effects of chromium and aluminum on the mechanical and oxidation properties of a series of gamma-prime-strengthened alloys based on CG-27 were studied. Gamma-prime dispersion and solid-solution strengthening were the principal modes of alloy strengthening. The oxidation attack parameter K sub a decreased with increasing Cr and Al contents for each alloy group based on Al content. As a group, alloys with 3 wt % Al had the lowest attack parameters. Therefore, 3 wt % is the optimum level of Al for parabolic oxidation behavior. Spalling, due to diffusion-induced grain growth, was controlled by the overall Cr and Al levels. The alloy with 4 wt % Cr and 3 wt % Al had stress-rupture properties superior to those of the base alloy, CG-27, and maintained parabolic oxidation behavior while the Cr content was reduced by two-thirds of its value in cast CG-27.

The influence of gamma prime on the recrystallization of an oxide dispersion strengthened superalloy - MA 6000E

NASA Technical Reports Server (NTRS)

Hotzler, R. K.; Glasgow, T. K.

1982-01-01

The requirement of large, recrystallized, highly elongated grains is of primary importance to the development of suitable high temperature properties in oxide dispersion strengthened-superalloys. In the present study the recrystallization behavior of MA 6000E, a recently developed Y2O3 strengthened superalloy produced by mechanical alloying, was examined using transmission and replication microscopy. Gradient and isothermal annealing treatments were applied to extruded and hot rolled products. It was found that conversion from a very fine (0.2 micron) grain structure to a coarse (approximately 10 mm) grain structure is controlled by the dissolution of the gamma prime phase, while grain shape was controlled primarily by the thermal gradient. The fine uniform oxide dispersion appeared to have only a secondary influence in determining the grain shape as columnar grains could be grown transverse to the working direction by appropriate application of the thermal gradient.

Eutectic superalloys by edge-defined, film-fed growth

NASA Technical Reports Server (NTRS)

Hurley, G. F.

1975-01-01

The feasibility of producing directionally solidified eutectic alloy composites by edge-defined, film-fed growth (EFG) was carried out. The three eutectic alloys which were investigated were gamma + delta, gamma/gamma prime + delta, and a Co-base TaC alloy containing Cr and Ni. Investigations into the compatibility and wettability of these metals with various carbides, borides, nitrides, and oxides disclosed that compounds with the largest (negative) heats of formation were most stable but poorest wetting. Nitrides and carbides had suitable stability and low contact angles but capillary rise was observed only with carbides. Oxides would not give capillary rise but would probably fulfill the other wetting requirements of EFG. Tantalum carbide was selected for most of the experimental portion of the program based on its exhibiting spontaneous capillary rise and satisfactory slow rate of degradation in the liquid metals. Samples of all three alloys were grown by EFG with the major experimental effort restricted to gamma + delta and gamma/gamma prime + delta alloys. In the standard, uncooled EFG apparatus, the thermal gradient was inferred from the growth speed and was 150 to 200 C/cm. This value may be compared to typical gradients of less than 100 C/cm normally achieved in a standard Bridgman-type apparatus. When a stream of helium was directed against the side of the bar during growth, the gradient was found to improve to about 250 C/cm. In comparison, a theoretical gradient of 700 C/cm should be possible under ideal conditions, without the use of chills. Methods for optimizing the gradient in EFG are discussed, and should allow attainment of close to the theoretical for a particular configuration.

Microstructure of selective laser melted CM247LC nickel-based superalloy and its evolution through heat treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Divya, V.D., E-mail: dv272@cam.ac.uk; Muñoz-Moreno, R.; Messé, O.M.D.M.

2016-04-15

The selective laser melting of high temperature alloys is of great interest to the aerospace industry as it offers the prospect of producing more complex geometries than can be achieved with other manufacturing methods. In this study, the microstructure of the nickel-based superalloy, CM247LC, has been characterised following selective laser melting and after a post deposition heat treatment below the γ′ solvus temperature. In the as-deposited state, scanning electron microscopy with electron backscatter diffraction revealed a fine, cellular microstructure with preferential alignment of 〈001〉 along the build direction. A high dislocation density was seen at the periphery of the cells,more » indicating substantial localised deformation of the material. Fine primary MC carbides were also observed in the inter-cellular regions. High-resolution transmission electron microscopy identified the occurrence of very fine γ′ precipitates, approximately 5 nm in diameter, dispersed within the gamma phase. After heat treatment, the elongated cell colonies were observed to partially coalesce, accompanied by a decrease in dislocation density, producing columnar grains along the build direction. Cuboidal γ′ precipitates approximately 500 nm in diameter were observed to form in the recrystallised grains, accompanied by larger γ′ precipitates on the grain boundaries.« less

Method of fission heat flux determination from experimental data

DOEpatents

Paxton, Frank A.

1999-01-01

A method is provided for determining the fission heat flux of a prime specimen inserted into a specimen of a test reactor. A pair of thermocouple test specimens are positioned at the same level in the holder and a determination is made of various experimental data including the temperature of the thermocouple test specimens, the temperature of bulk water channels located in the test holder, the gamma scan count ratios for the thermocouple test specimens and the prime specimen, and the thicknesses of the outer clads, the fuel fillers, and the backclad of the thermocouple test specimen. Using this experimental data, the absolute value of the fission heat flux for the thermocouple test specimens and prime specimen can be calculated.

Subliminal semantic priming changes the dynamic causal influence between the left frontal and temporal cortex.

PubMed

Matsumoto, Atsushi; Kakigi, Ryusuke

2014-01-01

Recent neuroimaging experiments have revealed that subliminal priming of a target stimulus leads to the reduction of neural activity in specific regions concerned with processing the target. Such findings lead to questions about the degree to which the subliminal priming effect is based only on decreased activity in specific local brain regions, as opposed to the influence of neural mechanisms that regulate communication between brain regions. To address this question, this study recorded EEG during performance of a subliminal semantic priming task. We adopted an information-based approach that used independent component analysis and multivariate autoregressive modeling. Results indicated that subliminal semantic priming caused significant modulation of alpha band activity in the left inferior frontal cortex and modulation of gamma band activity in the left inferior temporal regions. The multivariate autoregressive approach confirmed significant increases in information flow from the inferior frontal cortex to inferior temporal regions in the early time window that was induced by subliminal priming. In the later time window, significant enhancement of bidirectional causal flow between these two regions underlying subliminal priming was observed. Results suggest that unconscious processing of words influences not only local activity of individual brain regions but also the dynamics of neural communication between those regions.

Heme oxygenase-1 protects INF-gamma primed endothelial cells from Jurkat T-cell adhesion.

PubMed

Du, D; Chang, S; Chen, B; Zhou, H; Chen, Z K

2007-12-01

The heme oxygenase-1 (HO-1) system is associated with the rate-limiting step of conversion of heme, one of the most critical roles in cytoprotective mechanisms. Our study investigated its potential role in protection of endothelial cells from T cells. The recombinant plasmid pcDNA3-HO-1 was transfected into endothelial cells. Indirect fluorescent staining was used to examine the expression of HO-1 protein. Then endothelial cells primed by INF-gamma were mixed in culture with Jurkat T cells labeled with carboxyfluorescein diacetate succinimidyl ester (CFSE). The number of adhesive Jurkat T cells was determined using FACS to evaluate the adhesion effect. After being cultured with endothelial cells, the cell cycle of Jurkat T cells was detected using FACS. Expression of HO-1 on endothelial cells conferred significant protection against Jurkat T-cell-mediated adhesion. The rate of Jurkat T-cell adhesions was reduced to 19.06%, in contrast with 31.42% in the control group (P<.05). After using ZnPP, an inhibitor of HO-1, the rate of Jurkat T-cell adhesion recovered to 29.08%. The binding activities between endothelial cells and Jurkat T cells was blocked by HO-1 expression. The proliferation of Jurkat T cells was inhibited after culture with endothelial cells, which had been transfected with HO-1, which blocked cell cycle entry of T cells. More than 60% of Jurkat T cells remained in G0/G1 compared with 40% among the control group. HO-1 directly protected endothelial cells primed by INF-gamma from Jurkat T cells and down-regulated the expression of HLA-DR on the surface of endothelial cells. These results indicated that transgenic expression of HO-1 may be useful to prevent lymphocytes from responding to endothelial cells.

Poly-N-Acetylglucosamine Production by Staphylococcus epidermidis Cells Increases Their In Vivo Proinflammatory Effect

PubMed Central

Ferreirinha, Pedro; Pérez-Cabezas, Begoña; Correia, Alexandra; Miyazawa, Bruna; França, Angela; Carvalhais, Virgínia; Faustino, Augusto; Cordeiro-da-Silva, Anabela; Teixeira, Luzia; Pier, Gerald B.

2016-01-01

Poly-N-acetylglucosamine (PNAG) is a major component of the Staphylococcus epidermidis biofilm extracellular matrix. However, it is not yet clear how this polysaccharide impacts the host immune response and infection-associated pathology. Faster neutrophil recruitment and bacterial clearance were observed in mice challenged intraperitoneally with S. epidermidis biofilm cells of the PNAG-producing 9142 strain than in mice similarly challenged with the isogenic PNAG-defective M10 mutant. Moreover, intraperitoneal priming with 9142 cells exacerbated liver inflammatory pathology induced by a subsequent intravenous S. epidermidis challenge, compared to priming with M10 cells. The 9142-primed mice had elevated splenic CD4+ T cells producing gamma interferon and interleukin-17A, indicating that PNAG promoted cell-mediated immunity. Curiously, despite having more marked liver tissue pathology, 9142-primed mice also had splenic T regulatory cells with greater suppressive activity than those of their M10-primed counterparts. By showing that PNAG production by S. epidermidis biofilm cells exacerbates host inflammatory pathology, these results together suggest that this polysaccharide contributes to the clinical features associated with biofilm-derived infections. PMID:27481237

Fracture Kinetics of Hydrogen Embrittled Niobium.

DTIC Science & Technology

1981-03-01

Effects on Hydride Solvus 4...........4 2.3 Subcritical Crack Growth Behavior and Mechanism . . 6 2.4 Crack Propagation Measurements and Techniques... maraging steels in gaseous hydrogen, Hudak and Wei (18) ei has suggested that the KI independence of Stage II velocities is due to a rate limited...lattice decohesion model for hydrogen assisted cracking in steels . The occurrence of three stage behavior in hydrogen embrittled refractory alloys has

A Method for Locating a High-energy Dissipation Region in a Blazar

NASA Astrophysics Data System (ADS)

Yan, Dahai; Wu, Qingwen; Fan, Xuliang; Wang, Jiancheng; Zhang, Li

2018-06-01

The production site of gamma-rays in a blazar jet is an unresolved problem. We present a method to locate a gamma-ray emission region in the framework of a one-zone emission model. From measurements of the core-shift effect, the relation between the magnetic field strengths (B‧) in the radio cores of the jet and the distances (R) of these radio cores from the central supermassive black hole (SMBH) can be inferred. Therefore, once the magnetic field strength in the gamma-ray emission region ({B}diss}{\\prime }) is obtained, one can use the relation of B‧–R to derive the distance (R diss) of the gamma-ray emission region from the SMBH. Here, we evaluate the lower limit of {B}diss}{\\prime } by using the criteria that the optical variability timescale t var should be longer than or equal to the synchrotron radiation cooling timescale of the electrons that emit optical photons. We test the method with the observations of PSK 1510-089 and BL Lacertae, and derive {R}diss}< 0.15{δ }{{D}}1/3{(1+A)}2/3 pc for PSK 1510-089 with t var ∼ a few hours and {R}diss}< 0.003{δ }{{D}}1/3{(1+A)}2/3 pc for BL Lacertae with t var ∼ a few minutes. Here, δ D is the Doppler factor and A is the Compton dominance (i.e., the ratio of the Compton to the synchrotron peak luminosities).

Activation of mouse liver natural killer cells and NK1.1(+) T cells by bacterial superantigen-primed Kupffer cells.

PubMed

Dobashi, H; Seki, S; Habu, Y; Ohkawa, T; Takeshita, S; Hiraide, H; Sekine, I

1999-08-01

Although bacterial superantigens have been well characterized as potent stimulators of T cells, their role in natural killer (NK)-type cells remains largely unknown. In the present study, we examined the effect of bacterial superantigens on mouse liver NK cells and NK1.1 Ag(+) (NK1(+)) T cells. C57BL/6 mice were intravenously injected with staphylococcal enterotoxin B (SEB) or streptococcal pyrogenic exotoxin A (SPE-A), and mononuclear cells (MNC) of various organs were obtained from mice 4 hours after being injected with superantigen. MNC were cultured for 48 hours, and interferon gamma (IFN-gamma) levels of supernatants were measured. The antitumor cytotoxicities of the liver and spleen MNC were also evaluated 24 hours after the mice were injected with superantigen. Liver MNC produced more IFN-gamma than did splenocytes, and peripheral blood and lung MNC did not produce any detectable IFN-gamma. In addition, liver MNC acquired a potent antitumor cytotoxicity by the SEB injection, and both NK cells and NK1(+)T cells but not cluster of differentiation (CD)8(+) T cells were responsible for the cytotoxicity as demonstrated by either in vivo or in vitro cell depletion experiments, and the NK-type cells were partly responsible for the increased serum IFN-gamma. Activation of liver NK-type cells was also supported by the fact that liver NK cells proportionally increased and NK1(+) T cells augmented their CD11a expressions after SEB injection. The pretreatment of mice with anti-IFN-gamma Ab and/or with anti-interleukin-12 (IL-12) Ab diminished the SEB-induced cytotoxicity of liver MNC. Furthermore, the in vivo depletion of Kupffer cells decreased the SEB-induced cytotoxicity of liver MNC. Consistent with these results, liver MNC stimulated with superantigens in the presence of Kupffer cells in vitro produced a greater amount of IFN-gamma than did the liver MNC without Kupffer cells or splenocytes. Our results suggest that bacterial superantigen-primed Kupffer cells produce IL-12 and other monokines, while also nonspecifically activating both NK cells and NK1(+) T cells to produce IFN-gamma.

Time-dependent edge-notch sensitivity of oxide and gamma prime dispersion strengthened sheet materials at 1000 to 1800 F (538 - 982 C)

NASA Technical Reports Server (NTRS)

Wilson, D. J.

1972-01-01

Research was carried out to determine whether an oxide dispersion hardened alloy, TD-Ni, Cr, and low volume fraction gamma prime strengthened nickel-base alloy, Modified Waspaloy, were susceptible to time-dependent edge-notch sensitivity. The results were evaluated in terms of the mechanical characteristics of the alloys and the dislocation motion mechanisms operative. As far as could be determined, the results of the investigation were consistent with the following important concepts developed for Waspaloy and Inconel 718: (1) Time-dependent edge-notch sensitivity occurs when notched specimens are loaded below the approximate 0.2 percent smooth specimen offset yield strength and when data from smooth specimens indicate that small amounts of creep consume large rupture life fractions. (2) When precipitate particles are sheared by dislocations, the deformation is localized and time-dependent notch sensitivity occurs. When dislocations by-pass precipitate particles the deformation is homogeneous. Under these conditions, no time-dependent notch sensitivity has been observed.

Immunogenicity and protective efficacy of a recombinant yellow fever vaccine against the murine malarial parasite Plasmodium yoelii.

PubMed

Stoyanov, Cristina T; Boscardin, Silvia B; Deroubaix, Stephanie; Barba-Spaeth, Giovanna; Franco, David; Nussenzweig, Ruth S; Nussenzweig, Michel; Rice, Charles M

2010-06-23

The live-attenuated yellow fever vaccine (YF17D) is one of the safest and most effective vaccines available today. Here, YF17D was genetically altered to express the circumsporozoite protein (CSP) from the murine malarial parasite Plasmodium yoelii. Reconstituted recombinant virus was viable and exhibited robust CSP expression. Immunization of naïve mice resulted in extensive proliferation of adoptively transferred CSP-specific transgenic CD8(+) T-cells. A single immunization of naïve mice with recombinant YF17D resulted in robust production of IFN-gamma by CD8(+) T-cells and IFN-gamma and IL-2 by CD4(+) T-cells. A prime-boost regimen consisting of recombinant virus followed by a low-dose of irradiated sporozoites conferred protection against challenge with P. yoelii. Taken together, these results show that recombinant YF17D can efficiently express CSP in culture, and prime a protective immune response in vivo. (c) 2010 Elsevier Ltd. All rights reserved.

Transverse and longitudinal tensile properties at 760 C of several oxide dispersion strengthened nickel-base alloys

NASA Technical Reports Server (NTRS)

Anglin, A. E., Jr.

1979-01-01

The transverse and longitudinal tensile properties of the oxide dispersion strengthened nickel-base alloys were determined at 760 C. The alloys with small amounts of gamma prime have strength levels suitable for turbine vane applications, while other highly alloyed, gamma prime strengthened superalloys have strengths typical of turbine blade materials. These alloys were produced by mechanical alloying and extrusion and the turbine blade alloys were also directionally recrystallized. Resultant grain aspect ratios varied from 1:1 to over 20:1. Longitudinal tensile strengths ranged from 285 to 1175 MPa, while longitudinal elongations were in excess of 4 percent for all alloys. Transverse tensile strengths were comparable to longitudinal strengths, but transverse ductility levels were generally less than 2 percent elongation. Tensile and yield strengths increased with increasing strain rate over the range 0.001 to 0.05 per second. Ductility in both orientations was not strain rate sensitive but could be related to grain size and grain aspect ratio.

Human Asymptomatic Epitope Peptide/CXCL10-Based Prime/Pull Vaccine Induces Herpes Simplex Virus-Specific Gamma Interferon-Positive CD107+ CD8+ T Cells That Infiltrate the Cornea and Trigeminal Ganglia of Humanized HLA Transgenic Rabbits and Protect against Ocular Herpes Challenge.

PubMed

Khan, Arif A; Srivastava, Ruchi; Vahed, Hawa; Roy, Soumyabrata; Walia, Sager S; Kim, Grace J; Fouladi, Mona A; Yamada, Taikun; Ly, Vincent T; Lam, Cynthia; Lou, Anthony; Nguyen, Vivianna; Boldbaatar, Undariya; Geertsema, Roger; Fraser, Nigel W; BenMohamed, Lbachir

2018-06-13

Herpes simplex virus 1 (HSV-1) is a prevalent human pathogen that infects the cornea causing potentially blinding herpetic disease. A clinical herpes vaccine is still lacking. In the present study, a novel prime/pull vaccine was tested in Human Leukocyte Antigen- (HLA-) transgenic rabbit model of ocular herpes (HLA Tg rabbit). Three asymptomatic (ASYMP) peptide epitopes were selected from the HSV-1 membrane glycoprotein C (UL44 400-408 ), the DNA replication binding helicase (UL9 196-204 ), and the tegument protein (UL25 572-580 ), all preferentially recognized by CD8 + T cells from "naturally protected" HSV-1-seropositive healthy ASYMP individuals (who never had recurrent corneal herpetic disease). HLA Tg rabbits were immunized with a mixture of these three ASYMP CD8 + T cell peptide epitopes (UL44 400-408 , UL9 196-204 and UL25 572-580 ), delivered subcutaneously with CpG 2007 adjuvant (prime). Fifteen days later, half of the rabbits received a topical ocular treatment with a recombinant neurotropic AAV8 vector, expressing the T cell-attracting CXCL10 chemokine (pull). The frequency, function of HSV-specific CD8 + T cells induced by the prime/pull vaccine were assessed in peripheral blood, cornea, and trigeminal ganglia (TG). Compared to peptides alone, the peptides/CXCL10 prime/pull vaccine generated frequent polyfunctional gamma interferon-positive (IFN-γ + ) CD107 + CD8 + T cells that infiltrated both the cornea and TG. CD8 + T cells mobilization into cornea and TG of prime/pull- vaccinated rabbits was associated with a significant reduction in corneal herpes infection and disease following an ocular HSV-1 challenge (McKrae). These findings draw attention to the novel prime/pull vaccine strategy to mobilize anti-viral CD8 + T cells into tissues protecting them against herpes infection and disease. IMPORTANCE There is an urgent need for a vaccine against widespread herpes simplex virus infections. The present study demonstrates that immunization of HLA transgenic rabbits with a peptide/CXCL10 prime/pull vaccine triggered mobilization of HSV-specific CD8 + T cells locally in the cornea and TG, the sites of acute and latent herpes infections. Mobilization of antiviral CD8 + T cells into cornea and TG of rabbits that received the prime/pull vaccine was associated with protection against ocular herpes infection and disease following an ocular HSV-1 challenge. These results highlight the importance of the prime/pull vaccine strategy to bolster the number and function of protective CD8 + T cells within infected tissues. Copyright © 2018 American Society for Microbiology.

Isothermal and cyclic oxidation at 1000 and 1100 deg C of four nickel-base alloys: NASA-TRW VIA, B-1900, 713C, and 738X

NASA Technical Reports Server (NTRS)

Barrett, C. A.; Santoro, G. J.; Lowell, C. E.

1973-01-01

The isothermal and cyclic oxidation resistance of four cast Ni-base gamma + gamma prime alloys, NASA-TRW Via, B-1900, 713C, and 738X, was determined in still air at 1000 and 1100 C. The oxidation process was evaluated by specific sample weight change with time, sample thickness change, X-ray diffraction of the scales, and sample metallography. The behavior is discussed in terms of the Cr, Al, and refractory metal contents of the alloys.

Perforin and Gamma Interferon Expression Are Required for CD4+ and CD8+ T-Cell-Dependent Protective Immunity against a Human Parasite, Trypanosoma cruzi, Elicited by Heterologous Plasmid DNA Prime-Recombinant Adenovirus 5 Boost Vaccination▿

PubMed Central

de Alencar, Bruna C. G.; Persechini, Pedro M.; Haolla, Filipe A.; de Oliveira, Gabriel; Silverio, Jaline C.; Lannes-Vieira, Joseli; Machado, Alexandre V.; Gazzinelli, Ricardo T.; Bruna-Romero, Oscar; Rodrigues, Mauricio M.

2009-01-01

A heterologous prime-boost strategy using plasmid DNA, followed by replication-defective recombinant adenovirus 5, is being proposed as a powerful way to elicit CD4+ and CD8+ T-cell-mediated protective immunity against intracellular pathogens. We confirmed this concept and furthered existing research by providing evidence that the heterologous prime-boost regimen using the gene encoding amastigote surface protein 2 elicited CD4+ and CD8+ T-cell-mediated protective immunity (reduction of acute parasitemia and prolonged survival) against experimental infection with Trypanosoma cruzi. Protective immunity correlated with the presence of in vivo antigen-specific cytotoxic activity prior to challenge. Based on this, our second goal was to determine the outcome of infection after heterologous prime-boost immunization of perforin-deficient mice. These mice were highly susceptible to infection. A detailed analysis of the cell-mediated immune responses in immunized perforin-deficient mice showed an impaired gamma interferon (IFN-γ) secretion by immune spleen cells upon restimulation in vitro with soluble recombinant antigen. In spite of a normal numeric expansion, specific CD8+ T cells presented several functional defects detected in vivo (cytotoxicity) and in vitro (simultaneous expression of CD107a/IFN-γ or IFN-γ/tumor necrosis factor alpha) paralleled by a decreased expression of CD44 and KLRG-1. Our final goal was to determine the importance of IFN-γ in the presence of highly cytotoxic T cells. Vaccinated IFN-γ-deficient mice developed highly cytotoxic cells but failed to develop any protective immunity. Our study thus demonstrated a role for perforin and IFN-γ in a number of T-cell-mediated effector functions and in the antiparasitic immunity generated by a heterologous plasmid DNA prime-adenovirus boost vaccination strategy. PMID:19651871

Cyclopentadienylniobium and -molybdenum phosphorodithioate complexes. X-ray crystal structures of CpNbCl sub 3 (S sub 2 P(OPr sup i ) sub 2 ), CpNbCl(. mu. -Cl) sub 2 Nb(S sub 2 P(OPr sup i ) sub 2 )Cp, and cis-Cp prime Mo(CO) sub 2 (S sub 2 P(OPr sup i ) sub 2 )

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woodward, S.; Riaz, U.; Curtis, M.D.

1990-10-01

Reaction of CpNbCl{sub 4} (Cp = {eta}-C{sub 5}H{sub 5}) with (Pr{sup i}O){sub 2}P(S)(SH) in the presence of NEt{sub 3} yields CpNbCl{sub 3}(S{sub 2}P(S{sub 2}Pr{sup i}){sub 2}) (1). Reduction of 1 with Na/Hg affords the Nb-Nb-bonded complex CpNbCl({mu}-Cl){sub 2}Nb(S{sub 2}P(OR){sub 2})Cp (2). In refluxing toluene, (Pr{sup i}O){sub 2}P(S)(SH) with (Cp{prime}Mo(CO){sub 3}){sub 2} (Cp{prime} = {eta}-C{sub 5}H{sub 4}Me) gives cis-Cp{prime}Mo(CO){sub 2}(S{sub 2}P(OPr{sup i}){sub 2}) (3). Oxidation of 3 with I{sub 2} affords Cp{prime}MoI{sub 2}(CO)(S{sub 2}P(OPr{sup i}){sub 2}) (4). The crystal structures of 1-3 are compared. For 1, triclinic, P{bar 1}, a = 7.122 (3) {angstrom}, b = 11.365 (4) {angstrom}, c =more » 12.532 (4) {angstrom}, {alpha} = 77.38 (3){degree}, {beta} = 89.08 (3){degree}, {gamma} = 72.87 (3){degree}, V = 944.5 (8) {angstrom}{sup 3}. For 2, triclinic, P{bar 1}, a = 7.251 (3) {angstrom}, b = 12.386 (5) {angstrom}, c = 13.988 (5) {angstrom}, {alpha} = 102.66 (3){degree}, {beta} = 103.56 (3){degree}, {gamma} = 94.66 (3){degree}, V = 1180.0 (8) {angstrom}{sup 3}, Z = 2. For 3, orthorhombic, Pbca, a = 12.703 (3) {angstrom}, b = 16.707 (4) {angstrom}, c = 18.398 (4) {angstrom}, V = 3904.4 (17) {angstrom}{sup 3}, Z = 8.« less

Arthritis is developed in Borrelia-primed and -infected mice deficient of interleukin-17.

PubMed

Kuo, Joseph; Warner, Thomas F; Munson, Erik L; Nardelli, Dean T; Schell, Ronald F

2016-10-01

Interleukin-17 (IL-17) has been shown to participate in the development of Lyme arthritis in experimental mice. For example, neutralization of IL-17 with antibodies inhibits induction of arthritis in Borrelia-primed and -infected C57BL/6 wild-type mice. We hypothesized that mice lacking IL-17 would fail to develop Borrelia-induced arthritis. IL-17-deficient and wild-type C57BL/6 mice were primed with heat-inactivated Borrelia and then infected with viable spirochetes 3 weeks later. No swelling or major histopathological changes of the hind paws were detected in IL-17-deficient or wild-type mice that were primed with Borrelia or infected with viable spirochetes. By contrast, IL-17-deficient and wild-type mice that were primed and subsequently infected with heterologous Borrelia developed severe swelling and histopathological changes of the hind paws. In addition, Borrelia-primed and -infected IL-17-deficient mice exhibited elevated gamma-interferon (IFN-γ) levels in sera and increased frequencies of IFN-γ-expressing lymphocytes in popliteal lymph nodes compared to Borrelia-primed and -infected wild-type mice. These results demonstrate that IL-17 is not required for development of severe pathology in response to infection with Borrelia burgdorferi, but may contribute to disease through an interaction with IFN-γ. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The immunoglobulin class of anti-hapten antibody secreted during secondary responses in vitro and in vivo.

PubMed Central

North, J R; Dresser, D W

1977-01-01

A comparison has been made of the in vitro and in vivo response of primed mouse spleen cells to the hapten DNP. The responses were analysed in terms of six classes (sub-classes) of humoral antibody directed against the cross-reacting hapten TNP. By comparison with the response in intact mice the adoptive secondary response is delayed by 3 days in addition to being somewhat lesser in magnitude. The timing of the response in vitro is similar to that observed in intact mice. The preponderant class in all three responses was gammaG1 with gammaA and gammaG3 secreting cells consistently comprising the smallest proportion of the total of antibody-secreting cells. PMID:863475

The immunoglobulin class of anti-hapten antibody secreted during secondary responses in vitro and in vivo.

PubMed

North, J R; Dresser, D W

1977-05-01

A comparison has been made of the in vitro and in vivo response of primed mouse spleen cells to the hapten DNP. The responses were analysed in terms of six classes (sub-classes) of humoral antibody directed against the cross-reacting hapten TNP. By comparison with the response in intact mice the adoptive secondary response is delayed by 3 days in addition to being somewhat lesser in magnitude. The timing of the response in vitro is similar to that observed in intact mice. The preponderant class in all three responses was gammaG1 with gammaA and gammaG3 secreting cells consistently comprising the smallest proportion of the total of antibody-secreting cells.

SOME DUALITY THEOREMS FOR CYCLOTOMIC \\Gamma-EXTENSIONS OF ALGEBRAIC NUMBER FIELDS OF CM TYPE

NASA Astrophysics Data System (ADS)

Kuz'min, L. V.

1980-06-01

For an odd prime l and a cyclotomic \\Gamma{-}l-extension k_\\infty/k of a field k of CM type, a compact periodic \\Gamma-module A_l(k), analogous to the Tate module of a function field, is defined. The analog of the Weil scalar product is constructed on the module A_l(k). The properties of this scalar product are examined, and certain other duality relations are determined on A_l(k). It is proved that, in a finite l-extension k'/k of CM type, the \\mathbf{Z}_l-ranks of A_l(k) and A_l(k') are connected by a relation similar to the Hurwitz formula for the genus of a curve.Bibliography: 7 titles.

Intranasal boosting with an adenovirus-vectored vaccine markedly enhances protection by parenteral Mycobacterium bovis BCG immunization against pulmonary tuberculosis.

PubMed

Santosuosso, Michael; McCormick, Sarah; Zhang, Xizhong; Zganiacz, Anna; Xing, Zhou

2006-08-01

Parenterally administered Mycobacterium bovis BCG vaccine confers only limited immune protection from pulmonary tuberculosis in humans. There is a need for developing effective boosting vaccination strategies. We examined a heterologous prime-boost regimen utilizing BCG as a prime vaccine and our recently described adenoviral vector expressing Ag85A (AdAg85A) as a boost vaccine. Since we recently demonstrated that a single intranasal but not intramuscular immunization with AdAg85A was able to induce potent protection from pulmonary Mycobacterium tuberculosis challenge in a mouse model, we compared the protective effects of parenteral and mucosal booster immunizations following subcutaneous BCG priming. Protection by BCG prime immunization was not effectively boosted by subcutaneous BCG or intramuscular AdAg85A. In contrast, protection by BCG priming was remarkably boosted by intranasal AdAg85A. Such enhanced protection by intranasal AdAg85A was correlated to the numbers of gamma interferon-positive CD4 and CD8 T cells residing in the airway lumen of the lung. Our study demonstrates that intranasal administration of AdAg85A represents an effective way to boost immune protection by parenteral BCG vaccination.

Superalloy for high-temperature hydrogen environmental applications

NASA Technical Reports Server (NTRS)

McKannan, Eugene C. (Inventor); McPherson, William B. (Inventor); Ahmed, Shaffiq (Inventor); Chandler, Shirley S. (Inventor)

1991-01-01

A nickel-based superalloy is provided which is resistant to deterioration in hydrogen at high operating temperatures and pressures, and which thus can be used in hydrogen-fueled spacecraft such as the Space Shuttle. The superalloy is characterized by a two-phase microstructure and consists of a gamma-prime precipitated phase in a gamma matrix. The gamma matrix phase is a primary solid solution and the gamma precipitated phase will be an intermetallic compound of the type A.sub.3 B, such as nickel aluminide or titanide. Both phases are coherent, ordered, and compatible, and thus will retain most of their strength at elevated temperatures. The alloy consists essentially of (by weight): Ni 50-60%, Cr 10-20%, Al 2-6%, Co 2-5%, Ti 3-8%, W 5-12%, Mo 5-10%, Nb 1-3%, wherein the ratio W/MO is approximately equal to 1, and Ti/Al ranges from about 1 to about 2.

LPS induces direct death of IFN-gamma primed murine embryonic hepatocyte, BNL CL2 cells in a TNF-alpha independent manner.

PubMed

So, H S; Jung, B H; Yeum, S S; Park, J S; Kim, M S; Lee, J H; Chung, S Y; Choi, S; Chae, H J; Kim, H R; Ko, C B; Chung, H T; Park, R

2000-11-01

Although it has been well known that the role of LPS on liver damage is mediated through TNF-alpha, the mechanism by which LPS modulates the cytotoxicity of IFN-gamma on hepatocytes has not yet been clearly demonstrated. Here, we demonstrate that IFN-gamma mediated apoptosis in murine embryonic hepatocyte BNL CL2 cells is potentiated by the addition of LPS (0.5 microg/ml). Consistently, LPS markedly increases the catalytic activity of caspase 3-like protease but not caspase 1-like protease in IFN-gamma treated cells. In addition, TNF-alpha alone does not affect cell viability but rather it potentiates the cytotoxic effect of IFN-gamma on BNL CL2 cells. However, the cell viability of IFN-gamma/LPS treated cells is affected by the addition of polymyxin B but not by TNF binding protein I (TNF-BPI). These data suggest that the lipid moiety of LPS may mediate direct cytotoxicity of BNL CL2 cells in a TNF-alpha independent manner.

Rhodiola sachalinesis induces the expression of inducible nitric oxide synthase gene by murine fetal hepatocytes (BNL CL.2).

PubMed

Pae, H O; Seo, W G; Oh, G S; Kim, N Y; Kim, Y M; Kwon, T O; Shin, M K; Chai, K Y; Chung, H T

2001-02-01

We have examined the effect of the aqueous extract of Rhodiola sachalinensis root (RSE), a traditional herbal medicine, on nitric oxide (NO) synthesis in murine fetal hepatocytes (BNL CL.2) by measuring the stable end-product nitrite and the mRNA of inducible NO synthase (iNOS). Interferon-gamma (IFN-gamma) by itself failed to induce NO synthesis in BNL CL.2 cells. RSE also did not elicit NO synthesis at concentrations up to 1,000 microg/ml, but dose- and time-dependently induced NO synthesis in the presence of IFN-gamma in BNL CL.2 cells. Whereas RSE or IFN-gamma failed to induce detectable levels of iNOS mRNA, a combination of RSE and IFN-gamma markedly induced iNOS mRNA in BNL CL.2 cells. Thus, we found that RSE triggered IFN-gamma-primed BNL CL.2 cells to synthesize NO by inducing iNOS gene expression. The capability of RSE to induce NO synthesis might be related to the therapeutic efficacy of RSE on the liver diseases.

Nanoscale Characterization of Elemental Partitioning Between Gamma and Gamma Prime Phases in Rene 88DT Nickel Base Superalloy (Preprint)

DTIC Science & Technology

2008-02-01

penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN...analysis "as condu,ted on a FEI Tecnai F20 field emission gun transmission electron microscope operaling at 200 KV. Imagcs were obtained using lhe Cr M...line marked AI3 in (a). The neck region exhibil’ an inlensity lying in t>etween lhal of lhe yand y’phases. (c) Inlensily prot1le aemS > lhe line CD in (a

Joining precipitation-hardened nickel-base alloys by friction welding

NASA Technical Reports Server (NTRS)

Moore, T. J.

1972-01-01

Solid state deformation welding process, friction welding, has been developed for joining precipitation hardened nickel-base alloys and other gamma prime-strengthened materials which heretofore have been virtually unweldable. Method requires rotation of one of the parts to be welded, but where applicable, it is an ideal process for high volume production jobs.

Ionizing radiation potentiates the induction of nitric oxide synthase by interferon-gamma (Ifn-gamma) or Ifn-gamma and lipopolysaccharide in bnl cl.2 murine embryonic liver cells: role of hydrogen peroxide.

PubMed

Yoo, J C; Pae, H O; Choi, B M; Kim, W I; Kim, J D; Kim, Y M; Chung, H T

2000-02-01

The effects of ionizing irradiation on the nitric oxide (NO) production in murine embryonic liver cell line, BNL CL.2 cells, were investigated. Various doses (5-40 Gy) of radiation made BNL CL.2 cells responsive to interferon-gamma alone for the production of NO in a dose-dependent manner. Small amounts of lipopolysaccharide (LPS) or tumor necrosis factor-alpha (TNF-alpha) synergized with IFN-gamma in the production of NO from irradiated BNL CL.2 cells, even though LPS or TNF-alpha alone did not induce NO production from the same cells. Immunoblots showed parallel induction of inducible nitric oxide synthase (iNOS). NO production in irradiated BNL CL.2 cells by IFN-gamma or IFN-gamma plus LPS was decreased by the addition of catalase, suggesting that H(2)O(2) produced by ionizing irradiation primed the cells to trigger NO production in response to IFN-gamma or IFN-gamma plus LPS. Furthermore, the treatment of nongamma-irradiated BNL CL.2 cells with H(2)O(2) made the cells responsive to IFN-gamma or IFN-gamma plus LPS for the production of NO. This study shows that ionizing irradiation has the ability to induce iNOS gene expression in responsive to IFN-gamma via the formation of H(2)O(2) in BNL CL.2 murine embryonic liver cells.

Computational Thermodynamic Study to Predict Complex Phase Equilibria in the Nickel-Base Superalloy Rene N6

NASA Technical Reports Server (NTRS)

Copland, Evan H.; Jacobson, Nathan S.; Ritzert, Frank J.

2001-01-01

A previous study by Ritzert et al. on the formation and prediction of topologically closed packed (TCP) phases in the nickel-base superalloy Rene' N6 is re-examined with computational thermodynamics. The experimental data on phase distribution in forty-four alloys with a composition within the patent limits of the nickel-base superalloy Rene' N6 provide a good basis for comparison to and validation of a commercial nickel superalloy database used with ThermoCalc. Volume fraction of the phases and partitioning of the elements are determined for the forty-four alloys in this dataset. The baseline heat treatment of 400 h at 1366 K was used. This composition set is particularly interesting since small composition differences lead to dramatic changes in phase composition. In general the calculated values follow the experimental trends. However, the calculations indicated no TCP phase formation when the experimental measurements gave a volume percent of TCP phase less than 2 percent. When TCP phases were predicted, the calculations under-predict the volume percent of TCP phases by a factor of 2 to 8. The calculated compositions of the gamma and gamma' phases show fair agreement with the measurements. However, the calculated compositions of the P Phase do not agree with those measured. This may be due to inaccuracies in the model parameters for P phase and/or issues with the microprobe analyses of these phases. In addition, phase fraction diagrams and sigma and P phase solvus temperatures are calculated for each of the alloys. These calculations indicate that P phase is the primary TCP phase formed for the alloys considered here at 1366 K. Finally, a series of isopleths are calculated for each of the seven alloying elements. These show the effect of each alloying element on creating TCP phases.

Beneficial or Deleterious Effects of a Preexisting Hypersensitivity to Bacterial Components on the Course and Outcome of Infection

PubMed Central

Gumenscheimer, Marina; Mitov, Ivan; Galanos, Chris; Freudenberg, Marina A.

2002-01-01

Priming with heat-killed Propionibacterium acnes enhances the sensitivity of mice to lipopolysaccharide (LPS) and other biologically active bacterial components. We show that P. acnes priming has protective and deleterious effects on a subsequent serovar Typhimurium infection. It may result in a complete protection or prolonged survival, or it may accelerate mortality of the infected mice, depending on the number of serovar Typhimurium bacteria administered and on the degree of LPS hypersensitivity at the time of infection. Both effects of P. acnes-induced hypersensitivity are mediated by gamma interferon (IFN-γ) and are based on a differential activation of the innate immune mechanisms which recognize and react against the LPS present in infecting bacteria. In P. acnes-primed mice null for LPS-binding protein (LBP−/− mice), the impaired LPS recognition, due to the absence of LBP, resulted in a higher resistance to serovar Typhimurium infection. A similar P. acnes priming of mice had a protective, but no deleterious effect on a subsequent L. monocytogenes infection. This effect was IFN-γ dependent but independent of LBP. PMID:12228287

Oral immunization of mice with gamma-irradiated Brucella neotomae induces protection against intraperitoneal and intranasal challenge with virulent B. abortus 2308.

PubMed

Dabral, Neha; Martha-Moreno-Lafont; Sriranganathan, Nammalwar; Vemulapalli, Ramesh

2014-01-01

Brucella spp. are Gram-negative, facultative intracellular coccobacilli that cause one of the most frequently encountered zoonosis worldwide. Humans naturally acquire infection through consumption of contaminated dairy and meat products and through direct exposure to aborted animal tissues and fluids. No vaccine against brucellosis is available for use in humans. In this study, we tested the ability of orally inoculated gamma-irradiated B. neotomae and B. abortus RB51 in a prime-boost immunization approach to induce antigen-specific humoral and cell mediated immunity and protection against challenge with virulent B. abortus 2308. Heterologous prime-boost vaccination with B. abortus RB51 and B. neotomae and homologous prime-boost vaccination of mice with B. neotomae led to the production of serum and mucosal antibodies specific to the smooth LPS. The elicited serum antibodies included the isotypes of IgM, IgG1, IgG2a, IgG2b and IgG3. All oral vaccination regimens induced antigen-specific CD4(+) and CD8(+) T cells capable of secreting IFN-γ and TNF-α. Upon intra-peritoneal challenge, mice vaccinated with B. neotomae showed the highest level of resistance against virulent B. abortus 2308 colonization in spleen and liver. Experiments with different doses of B. neotomae showed that all tested doses of 10(9), 10(10) and 10(11) CFU-equivalent conferred significant protection against the intra-peritoneal challenge. However, a dose of 10(11) CFU-equivalent of B. neotomae was required for affording protection against intranasal challenge as shown by the reduced bacterial colonization in spleens and lungs. Taken together, these results demonstrate the feasibility of using gamma-irradiated B. neotomae as an effective and safe oral vaccine to induce protection against respiratory and systemic infections with virulent Brucella.

Selective Growth of Low Stored Energy Grains During δ Sub-solvus Annealing in the Inconel 718 Nickel-Based Superalloy

NASA Astrophysics Data System (ADS)

Agnoli, Andrea; Bernacki, Marc; Logé, Roland; Franchet, Jean-Michel; Laigo, Johanne; Bozzolo, Nathalie

2015-09-01

The microstructure stability during δ sub-solvus annealing in Inconel 718 was investigated, focusing on the conditions that may lead to the development of very large grains (about 100 μm) in a recrystallized fine grained matrix (4 to 5 μm) despite the presence of second-phase particles. Microstructure evolution was analyzed by EBSD (grain size, intragranular misorientation) and SEM ( δ phase particles). Results confirm that, in the absence of stored energy, the grain structure is controlled by the δ phase particles, as predicted by the Smith-Zener equation. If the initial microstructure is strained ( ɛ < 0.1) before annealing, then low stored energy grains grow to a large extent, despite the Zener pinning forces exerted by the second-phase particles on the grain boundaries. Those selectively growing grains could be those of the initial microstructure that were the least deformed, or they could result from a nucleation process. The balance of three forces acting on boundary migration controls the growth process: if the sum of capillarity and stored energy driving forces exceeds the Zener pinning force, then selective grain growth occurs. Such phenomenon could be simulated, using a level set approach in a finite element context, by taking into account the three forces acting on boundary migration and by considering a realistic strain energy distribution (estimated from EBSD measurements).

Recalibration of the sphalerite cosmobarometer: Experimental and theoretical treatment

NASA Astrophysics Data System (ADS)

Balabin, Alexey I.; Urusov, Vadim S.

1995-04-01

Temperature dependence of the composition of sphalerite in equilibrium with troilite + metallic iron has been determined experimentally from 400 to 840°C at 1 bar. The high-temperature runs (660-840°C) were conducted in evacuated silica tubes; a new version of the recrystallization in anhydrous halide flux technique was used for attaining equilibrium at 600-400°C. The zero-pressure solvus of sphalerite proved to be at higher FeS contents than was located by Barton and Toulmin (1966). Detailed calculations, based on updated thermochemical appraisal of the sphalerite (Zn,Fe)S solution, have shown the new solvus to be in apparent consistency with the high-pressure experimental data of Hutchison and Scott (1983 ). An improved calibration of the cosmobarometer is presented, based on our experimental results and those of Hutchison and Scott (1983) ; the calibration takes into account some inferences regarding thermodynamic properties of sphalerite solution and low-temperature polymorphism in FeS. Recently published metallographic cooling rates of iron meteorites (Saikumar and Goldstein, 1988) provide estimates of blocking temperatures for Fe diffusion in sphalerite, which fall in the range 205-217°C. Pressures of formation of these meteorites calculated from available sphalerite compositions range from 0 for Landes to 1.8 kbar for Toluca. The most reliable of the pressure estimates exhibit a linear relationship with wt% Ni of the meteorite.

The Potential Link Between High Angle Grain Boundary Morphology and Grain Boundary Deformation in a Nickel-Based Superalloy (Postprint)

DTIC Science & Technology

2015-06-01

Ghosh, M.K. Samal , Multiscale Crystal Plasticity Modeling of Microtwinning Induced Deformation in Gamma–Gamma Prime Nickel Based Superalloys, Shanghai...University, Shanghai, Peoples Republic of China, 2011, pp. 487–488. [3] H. Deuchman, P.J. Phillips, N. Zhou, M. Samal , S. Ghosh, Y. Wang, M.J. Mills

B cells are not essential for Lactobacillus-mediated protection against lethal pneumovirus infection*

PubMed Central

Percopo, Caroline M.; Dyer, Kimberly D.; Garcia-Crespo, Katia E.; Gabryszewski, Stanislaw J.; Shaffer, Arthur L.; Domachowske, Joseph B.; Rosenberg, Helene F.

2014-01-01

We have shown previously that priming of respiratory mucosa with live Lactobacillus species promotes robust and prolonged survival from an otherwise lethal infection with pneumonia virus of mice (PVM), a property known as heterologous immunity. Lactobacillus-priming results in a moderate reduction in virus recovery and a dramatic reduction in virus-induced proinflammatory cytokine production; the precise mechanisms underlying these findings remain to be elucidated. As B cells have been shown to promote heterologous immunity against respiratory virus pathogens under similar conditions, here we explore the role of B cells in Lactobacillus-mediated protection against acute pneumovirus infection. We found that Lactobacillus-primed mice feature elevated levels of airway immunoglobulins IgG, IgA and IgM and lung tissues with dense, B cell (B220+) enriched peribronchial and perivascular infiltrates with germinal centers consistent with descriptions of bronchus-associated lymphoid tissue. No B cells were detected in lung tissue of Lactobacillus-primed B-cell deficient μMT mice or Jh mice, and Lactobacillus-primed μMT mice had no characteristic infiltrates or airway immunoglobulins. Nonetheless, we observed diminished virus recovery and profound suppression of virus-induced proinflammatory cytokines CCL2, IFN-gamma, and CXCL10 in both wild-type and Lactobacillus-primed μMT mice. Furthermore, L. plantarum-primed, B-cell deficient μMT and Jh mice were fully protected from an otherwise lethal PVM infection, as were their respective wild-types. We conclude that B cells are dispensable for Lactobacillus-mediated heterologous immunity and were not crucial for promoting survival in response to an otherwise lethal pneumovirus infection. PMID:24748495

Radiation lesion to liver DNA of rats exposed to radiation during flight aboard the Kosmos-690 biosatellite. [Effect of weightlessness on. gamma. -radioinduced DNA strand breaks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komolova, G.S.; Makeeva, V.F.; Egorov, I.A.

1978-10-26

A prime role is attributed to disturbances in DNA structure of nuclear chromatin as the mechanisms of radiation lesions in living cells. For this reason, it may be assumed that a change in the biological effectiveness of radiation delivered to animals under conditions that are extreme for vital functions, including space flight, may occur via modification of radiolesions in chromatin DNA. For this reason, the DNA of rats exposed to radiation from an onboard gamma source in the course of an actual space flight in the Kosmos-690 biosatellite was examined.

Temporal Evolution of the Nanostructure and Phase Compositions in a Model Ni-Al-Cr Alloy

NASA Technical Reports Server (NTRS)

Sudbrack, Chantal K.; Yoon, Kevin E.; Seidman, David N.; Seidman, David N.

2006-01-01

In a Ni-5.2 Al-14.2 Cr at.% alloy with moderate solute supersaturations and a very small gamma/gamma prime lattice parameter misfit, the nanostructural and compositional pathways during gamma prime(L12) precipitation at 873 K are investigated using atom-probe tomography, conventional transmission electron microscopy, and hardness measurements. Nucleation of high number densities (N(sub v) greater than 10(sup 23) per cubic meters) of solute-rich precipitates (mean radius = [R] = 0.75 nm), with a critical nucleus composition of Ni-18.3 plus or minus 0.9 Al-9.3 plus or minus 0.7 Cr at.%, initiates between 0.0833 and 0.167 h. With increasing aging time (a) the solute concentrations decay in spheroidal precipitates ([R] less than 10 nm); (b) the observed early-stage coalescence peaks at maximum N(sub v) in coincidence with the smallest interprecipitate spacing; and (c) the reaction enters a quasi-stationary regime where growth and coarsening operate concomitantly. During this quasi-stationary regime, the c (face-centered cubic)-matrix solute supersaturations decay with a power-law dependence of about -1/3, while the dependencies of [R] and N(sub v) are 0.29 plus or minus 0.05 and -0.64 plus or minus 0.06 at a coarsening rate slower than model predications. Coarsening models allow both equilibrium phase compositions to be determined from the compositional measurements. The observed early-stage coalescence is discussed in further detail.

A Comparison of the Plastic Flow Response of a Powder Metallurgy Nickel Base Superalloy (Postprint)

DTIC Science & Technology

2017-04-01

average diameter of 315 nm. The c¢-solvus tempera- ture, Tc0 , was 1430 K (1157 C). As determined by a series of long- time heat treatments followed...obtained in a mode of simple shear via the torsion of tubular samples. Similar in design to that employed by various researchers in the 1980s,[28,29] the...INTL (STINFO COPY) AIR FORCE RESEARCH LABORATORY MATERIALS AND MANUFACTURING DIRECTORATE WRIGHT-PATTERSON AIR FORCE BASE, OH 45433-7750 AIR

A tuberculosis vaccine based on phosphoantigens and fusion proteins induces distinct gammadelta and alphabeta T cell responses in primates.

PubMed

Cendron, Delphine; Ingoure, Sophie; Martino, Angelo; Casetti, Rita; Horand, Françoise; Romagné, François; Sicard, Hélène; Fournié, Jean-Jacques; Poccia, Fabrizio

2007-02-01

Phosphoantigens are mycobacterial non-peptide antigens that might enhance the immunogenicity of current subunit candidate vaccines for tuberculosis. However, their testing requires monkeys, the only animal models suitable for gammadelta T cell responses to mycobacteria. Thus here, the immunogenicity of 6-kDa early secretory antigenic target-mycolyl transferase complex antigen 85B (ESAT-6-Ag85B) (H-1 hybrid) fusion protein associated or not to a synthetic phosphoantigen was compared by a prime-boost regimen of two groups of eight cynomolgus. Although phosphoantigen activated immediately a strong release of systemic Th1 cytokines (IL-2, IL-6, IFN-gamma, TNF-alpha), it further anergized blood gammadelta T lymphocytes selectively. By contrast, the hybrid H-1 induced only memory alphabeta T cell responses, regardless of phosphoantigen. These latter essentially comprised cytotoxic T lymphocytes specific for Ag85B (on average + 430 cells/million PBMC) and few IFN-gamma-secreting cells (+ 40 cells/million PBMC, equally specific for ESAT-6 and for Ag85B). Hence, in macaques, a prime-boost with the H-1/phosphoantigen subunit combination induces two waves of immune responses, successively by gammadelta T and alphabeta T lymphocytes.

IL-15 induces antigen-independent expansion and differentiation of human naive CD8+ T cells in vitro.

PubMed

Alves, Nuno L; Hooibrink, Berend; Arosa, Fernando A; van Lier, René A W

2003-10-01

Recent studies in mice have shown that although interleukin 15 (IL-15) plays an important role in regulating homeostasis of memory CD8+ T cells, it has no apparent function in controlling homeostatic proliferation of naive T cells. We here assessed the influence of IL-15 on antigen-independent expansion and differentiation of human CD8+ T cells. Both naive and primed human T cells divided in response to IL-15. In this process, naive CD8+ T cells successively down-regulated CD45RA and CD28 but maintained CD27 expression. Concomitant with these phenotypic changes, naive cells acquired the ability to produce interferon gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha), expressed perforin and granzyme B, and acquired cytotoxic properties. Primed CD8+ T cells, from both noncytotoxic (CD45RA-CD27+) and cytotoxic (CD45RA+CD27-) subsets, responded to IL-15 and yielded ample numbers of cytokine-secreting and cytotoxic effector cells. In summary, all human CD8+ T-cell subsets had the ability to respond to IL-15, which suggests a generic influence of this cytokine on CD8+ T-cell homeostasis in man.

Creep and rupture of an ODS alloy with high stress rupture ductility. [Oxide Dispersion Strengthened

NASA Technical Reports Server (NTRS)

Mcalarney, M. E.; Arsons, R. M.; Howson, T. E.; Tien, J. K.; Baranow, S.

1982-01-01

The creep and stress rupture properties of an oxide (Y2O3) dispersion strengthened nickel-base alloy, which also is strengthened by gamma-prime precipitates, was studied at 760 and 1093 C. At both temperatures, the alloy YDNiCrAl exhibits unusually high stress rupture ductility as measured by both elongation and reduction in area. Failure was transgranular, and different modes of failure were observed including crystallographic fracture at intermediate temperatures and tearing or necking almost to a chisel point at higher temperatures. While the rupture ductility was high, the creep strength of the alloy was low relative to conventional gamma prime strengthened superalloys in the intermediate temperature range and to ODS alloys in the higher temperature range. These findings are discussed with respect to the alloy composition; the strengthening oxide phases, which are inhomogeneously dispersed; the grain morphology, which is coarse and elongated and exhibits many included grains; and the second phase inclusion particles occurring at grain boundaries and in the matrix. The creep properties, in particular the high stress dependencies and high creep activation energies measured, are discussed with respect to the resisting stress model of creep in particle strengthened alloys.

Mycobacterium leprae-Infected Macrophages Preferentially Primed Regulatory T Cell Responses and Was Associated with Lepromatous Leprosy.

PubMed

Yang, Degang; Shui, Tiejun; Miranda, Jake W; Gilson, Danny J; Song, Zhengyu; Chen, Jia; Shi, Chao; Zhu, Jianyu; Yang, Jun; Jing, Zhichun

2016-01-01

The persistence of Mycobacterium leprae (M. leprae) infection is largely dependent on the types of host immune responses being induced. Macrophage, a crucial modulator of innate and adaptive immune responses, could be directly infected by M. leprae. We therefore postulated that M. leprae-infected macrophages might have altered immune functions. Here, we treated monocyte-derived macrophages with live or killed M. leprae, and examined their activation status and antigen presentation. We found that macrophages treated with live M. leprae showed committed M2-like function, with decreased interleukin 1 beta (IL-1beta), IL-6, tumor necrosis factor alpha (TNF-alpha) and MHC class II molecule expression and elevated IL-10 and CD163 expression. When incubating with naive T cells, macrophages treated with live M. leprae preferentially primed regulatory T (Treg) cell responses with elevated FoxP3 and IL-10 expression, while interferon gamma (IFN-gamma) expression and CD8+ T cell cytotoxicity were reduced. Chromium release assay also found that live M. leprae-treated macrophages were more resistant to CD8+ T cell-mediated cytotoxicity than sonicated M. leprae-treated monocytes. Ex vivo studies showed that the phenotype and function of monocytes and macrophages had clear differences between L-lep and T-lep patients, consistent with the in vitro findings. Together, our data demonstrate that M. leprae could utilize infected macrophages by two mechanisms: firstly, M. leprae-infected macrophages preferentially primed Treg but not Th1 or cytotoxic T cell responses; secondly, M. leprae-infected macrophages were more effective at evading CD8+ T cell-mediated cytotoxicity.

Identification of Pertussis-Specific Effector Memory T Cells in Preschool Children

PubMed Central

Schure, Rose-Minke; Öztürk, Kemal; Berbers, Guy; Sanders, Elisabeth; van Twillert, Inonge; Carollo, Maria; Mascart, Françoise; Ausiello, Clara M.; van Els, Cecile A. C. M.; Smits, Kaat; Buisman, Anne-Marie

2015-01-01

Whooping cough remains a problem despite vaccination, and worldwide resurgence of pertussis is evident. Since cellular immunity plays a role in long-term protection against pertussis, we studied pertussis-specific T-cell responses. Around the time of the preschool acellular pertussis (aP) booster dose at 4 years of age, T-cell memory responses were compared in children who were primed during infancy with either a whole-cell pertussis (wP) or an aP vaccine. Peripheral blood mononuclear cells (PBMCs) were isolated and stimulated with pertussis vaccine antigens for 5 days. T cells were characterized by flow-based analysis of carboxyfluorescein succinimidyl ester (CFSE) dilution and CD4, CD3, CD45RA, CCR7, gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α) expression. Before the aP preschool booster vaccination, both the proliferated pertussis toxin (PT)-specific CD4+ and CD8+ T-cell fractions (CFSEdim) were higher in aP- than in wP-primed children. Post-booster vaccination, more pertussis-specific CD4+ effector memory cells (CD45RA− CCR7−) were induced in aP-primed children than in those primed with wP. The booster vaccination did not appear to significantly affect the T-cell memory subsets and functionality in aP-primed or wP-primed children. Although the percentages of Th1 cytokine-producing cells were alike in aP- and wP-primed children pre-booster vaccination, aP-primed children produced more Th1 cytokines due to higher numbers of proliferated pertussis-specific effector memory cells. At present, infant vaccinations with four aP vaccines in the first year of life result in pertussis-specific CD4+ and CD8+ effector memory T-cell responses that persist in children until 4 years of age and are higher than those in wP-primed children. The booster at 4 years of age is therefore questionable; this may be postponed to 6 years of age. PMID:25787136

Single-Cell Transcriptomics Reveals a Population of Dormant Neural Stem Cells that Become Activated upon Brain Injury.

PubMed

Llorens-Bobadilla, Enric; Zhao, Sheng; Baser, Avni; Saiz-Castro, Gonzalo; Zwadlo, Klara; Martin-Villalba, Ana

2015-09-03

Heterogeneous pools of adult neural stem cells (NSCs) contribute to brain maintenance and regeneration after injury. The balance of NSC activation and quiescence, as well as the induction of lineage-specific transcription factors, may contribute to diversity of neuronal and glial fates. To identify molecular hallmarks governing these characteristics, we performed single-cell sequencing of an unbiased pool of adult subventricular zone NSCs. This analysis identified a discrete, dormant NSC subpopulation that already expresses distinct combinations of lineage-specific transcription factors during homeostasis. Dormant NSCs enter a primed-quiescent state before activation, which is accompanied by downregulation of glycolytic metabolism, Notch, and BMP signaling and a concomitant upregulation of lineage-specific transcription factors and protein synthesis. In response to brain ischemia, interferon gamma signaling induces dormant NSC subpopulations to enter the primed-quiescent state. This study unveils general principles underlying NSC activation and lineage priming and opens potential avenues for regenerative medicine in the brain. Copyright © 2015 Elsevier Inc. All rights reserved.

Helminth antigens selectively differentiate unsensitized CD45RA+ CD4+ human T cells in vitro.

PubMed

Steel, C; Nutman, T B

1998-01-01

Human filarial helminth infections are characterized by type 2 immune responses to parasite Ag that can persist for the life of the individual; one possible cause for this may be prenatal exposure to the blood-borne microfilarial (Mf) stage of the parasite. To examine the relationship between early exposure to filarial Ag and subsequent immune responsiveness, CD45RA+ CD4+ cells frp, normal unsensitized donors were stimulated in vitro with soluble microfilarial Ag (MfAg) from the filarial parasite Brugia malayi in the presence of APCs. MfAg alone induced proliferation and IFN-gamma and IL-5 production in unsensitized CD45RA+ CD4+ cells, demonstrating the ability of filarial Ags to prime naive T cells in the absence of exogenous cytokines and dendritic cells. Adding exogenous cytokine(s) (particularly IL-12 and IL-4) during priming was able to alter the MfAg-specific responses of CD45RA+ CD4+ cells as well as subsequent responses to Ag. Interestingly, priming solely with MfAg led to enhanced IL-5 production following Ag restimulation, suggesting that MfAg preferentially primes for type 2 responses. These data demonstrate that filarial Ags by themselves can specifically prime CD45RA+ CD4+ cells in vitro and do so in such a way as to deviate the immune response.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samskog, P.; Kispert, L.D.; Lund, A.

Four different alkoxy radicals were identified by ESR studies in x-ray irradiated single crystals of trehalose. The radical sites are O/sup prime//sub 2/(I), O/sub 2/(II), O/sup prime//sub 3/(III), and the probable ring oxygen O/sub 5/(IV). All alkoxy radicals exhibit one or two ..beta..-proton couplings. An additional coupling to a ..gamma.. proton for radical II is observed. The difference in the g/sub max/ value for the alkoxy radicals is discussed in terms of the type of hydrogen bonding involved. Two hydroxyalkyl radicals VI and VII were also produced at 77 K. Storage of crystals for one week results in decay ofmore » radicals I and II. Alkoxy radical II transform into a C/sub 6/-centered hydroxyalkyl radical V.« less

T cell cytokine polarity as a determinant of immunoglobulin A (IgA) glycosylation and the severity of experimental IgA nephropathy.

PubMed

Chintalacharuvu, S R; Yamashita, M; Bagheri, N; Blanchard, T G; Nedrud, J G; Lamm, M E; Tomino, Y; Emancipator, S N

2008-09-01

Immunoglobulin A (IgA) glycosylation, recognized as an important pathogenic factor in IgA nephropathy (IgAN), is apparently controlled by the polarity of T helper (Th) cytokine responses. To examine the role of cytokine polarity in IgAN, inbred mice were immunized by intraperitoneal priming with inactivated Sendai virus (SeV) emulsified in either complete Freund's adjuvant (CFA) or incomplete Freund's adjuvant (IFA), which promote Th1- or Th2-immune response, respectively, and then boosted identically twice orally with aqueous suspensions of inactivated virus. Next, some mice were challenged intranasally with infectious SeV. Mice primed with CFA or IFA had equal reductions in nasal viral titre relative to non-immune controls, and equally increased serum levels of SeV-specific IgA antibody. Mice primed with CFA showed higher SeV-specific IgG than those with IFA. Splenocytes from mice primed with IFA produced copious amounts of interleukin (IL)-4 and IL-5, but little interferon-gamma and IL-2; those primed with CFA had reciprocal cytokine recall responses. Total serum IgA and especially SeV-specific IgA from mice primed with IFA showed a selective defect in sialylation and galactosylation. Although the frequency and intensity of glomerular deposits and haematuria did not differ, glomerulonephritis in mice primed with IFA and challenged with infectious virus was more severe than in those given CFA, as judged by serum creatinine level. We conclude that the polarity of T cell cytokines controls the pattern of IgA glycosylation and exerts direct or indirect effects on functional glomerular responses to immune complex deposition.

The Advanced Gamma-ray Imaging System (AGIS): Telescope Optical System Designs

NASA Astrophysics Data System (ADS)

Vassiliev, Vladimir; Buckley, Jim; Falcone, Abe; Fegan, Steven; Finley, John; Gaurino, Victor; Hanna, David; Kaaret, Philip; Konopelko, Alex; Krawczynski, Henric; Romani, Roger; Weekes, Trevor

2008-04-01

AGIS is a conceptual design for a future ground-based gamma-ray observatory based on an array of ˜100 imaging atmospheric Cherenkov telescopes (IACTs) with a sensitivity to gamma-rays in the energy range 40 GeV-100 TeV. The anticipated improvement of AGIS sensitivity, angular resolution, and reliability of operation imposes demanding technological and cost requirements on the design of the IACTs. In this submission we focus on the optical system (OS) of the AGIS telescopes and consider options which include traditional Davies-Cotton and the other prime- focus telescope designs, as well as a novel two-mirror aplanatic OS originally proposed by Schwarzschild. Emerging new mirror production technologies based on replication processes such as cold and hot glass slumping, cured CFRP, and electroforming provide new opportunities for cost effective solutions for the design of the OS. We evaluate the capabilities of these mirror fabrication methods for the AGIS project.

Low-dose radiation modifies skin response to acute gamma-rays and protons.

PubMed

Mao, Xiao Wen; Pecaut, Michael J; Cao, Jeffrey D; Moldovan, Maria; Gridley, Daila S

2013-01-01

The goal of the present study was to obtain pilot data on the effects of protracted low-dose/low-dose-rate (LDR) γ-rays on the skin, both with and without acute gamma or proton irradiation (IR). Six groups of C57BL/6 mice were examined: a) 0 Gy control, b) LDR, c) Gamma, d) LDR+Gamma, e) Proton, and f) LDR+Proton. LDR radiation was delivered to a total dose of 0.01 Gy (0.03 cGy/h), whereas the Gamma and Proton groups received 2 Gy (0.9 Gy/min and 1.0 Gy/min, respectively). Assays were performed 56 days after exposure. Skin samples from all irradiated groups had activated caspase-3, indicative of apoptosis. The significant (p<0.05) increases in immunoreactivity in the Gamma and Proton groups were not present when LDR pre-exposure was included. However, the terminal deoxynucleotidyl transferase dUTP nick-end labeling assay for DNA fragmentation and histological examination of hematoxylin and eosin-stained sections revealed no significant differences among groups, regardless of radiation regimen. The data demonstrate that caspase-3 activation initially triggered by both forms of acute radiation was greatly elevated in the skin nearly two months after whole-body exposure. In addition, LDR γ-ray priming ameliorated this response.

The effects of temperature gradient and growth rate on the morphology and fatigue properties of MAR-M246(Hf)

NASA Technical Reports Server (NTRS)

Schmidt, D. D.; Alter, W. S.; Hamilton, W. D.; Parr, R. A.

1989-01-01

MAR-M246(Hf) is a nickel based superalloy used in the turbopump blades of the Space Shuttle main engines. The effects are considered of temperature gradient (G) and growth rate (R) on the microstructure and fatigue properties of this superalloy. The primary dendrite arm spacings were found to be inversely proportional to both temperature gradient and growth rate. Carbide and gamma - gamma prime morphology trends were related to G/R ratios. Weibull analysis of fatigue results shows the characteristic life to be larger by a factor of 10 for the low gradient/fast rate pairing of G and R, while the reliability (beta) was lower.

Crystallization and characterization of Y2O3-SiO2 glasses

NASA Technical Reports Server (NTRS)

Drummond, C. H., III; Lee, W. E.; Sanders, W. A.; Kiser, J. D.

1988-01-01

Glasses in the yttria-silica system with 20-40 mol pct Y2O3 have been subjected to recrystallization studies after melting at 1900-2100 C in W crucibles in 1 and 50 atm N2. The TEM and XRD results obtained indicate the presence of the delta, gamma, gamma-prime, and beta-Y2Si2O7 crystalline phases, depending on melting and quenching conditions. Heat-treatment in air at 1100-1600 C increased the amount of crystallization, and led to the formation of Y2SiO5, cristobalite, and polymorphs of Y2Si2O7. Also investigated were the effects of 5 and 10 wt pct zirconia additions.

Mechanical properties of modified low cobalt powder metallurgy Udimet 700 type alloys

NASA Technical Reports Server (NTRS)

Harf, Fredric H.

1989-01-01

Eight superalloys derived from Udimet 700 were prepared by powder metallurgy, hot isostatically pressed, heat treated and their tensile and creep rupture properties determined. Several of these alloys displayed properties superior to those of Udimet 700 similarly prepared, in one case exceeding the creep rupture life tenfold. Filter clogging by extracted gamma prime, its measurement and significance are discussed in an appendix.

Hematopoietic stem cell loss and hematopoietic failure in severe aplastic anemia is driven by macrophages and aberrant podoplanin expression.

PubMed

McCabe, Amanda; Smith, Julianne N P; Costello, Angelica; Maloney, Jackson; Katikaneni, Divya; MacNamara, Katherine C

2018-05-17

Severe aplastic anemia results from profound hematopoietic stem cell loss. T cells and interferon gamma have long been associated with severe aplastic anemia, yet the underlying mechanisms driving hematopoietic stem cell loss remain unknown. Using a mouse model of severe aplastic anemia, we demonstrate that interferon gamma-dependent hematopoietic stem cell loss required macrophages. Interferon gamma was necessary for bone marrow macrophage persistence, despite loss of other myeloid cells and hematopoietic stem cells. Depleting macrophages or abrogating interferon gamma signaling specifically in macrophages did not impair T cell activation or interferon gamma production in the bone marrow but rescued hematopoietic stem cells and reduced mortality. Thus, macrophages are not required for induction of interferon gamma in severe aplastic anemia and rather act as sensors of interferon gamma. Macrophage depletion rescued thrombocytopenia, increased bone marrow megakaryocytes, preserved platelet-primed stem cells, and increased the platelet-repopulating capacity of transplanted hematopoietic stem cells. In addition to the hematopoietic effects, severe aplastic anemia induced loss of non-hematopoietic stromal populations, including podoplanin-positive stromal cells. However, a subset of podoplanin-positive macrophages was increased during disease, and blockade of podoplanin in mice was sufficient to rescue disease. Our data further our understanding of disease pathogenesis demonstrating a novel role for macrophages as sensors of interferon gamma, thus illustrating an important role for the microenvironment in pathogenesis of severe aplastic anemia. Copyright © 2018, Ferrata Storti Foundation.

The cAMP signaling system inhibits the repair of {gamma}-ray-induced DNA damage by promoting Epac1-mediated proteasomal degradation of XRCC1 protein in human lung cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cho, Eun-Ah; Juhnn, Yong-Sung, E-mail: juhnn@snu.ac.kr

2012-06-01

Highlights: Black-Right-Pointing-Pointer cAMP signaling system inhibits repair of {gamma}-ray-induced DNA damage. Black-Right-Pointing-Pointer cAMP signaling system inhibits DNA damage repair by decreasing XRCC1 expression. Black-Right-Pointing-Pointer cAMP signaling system decreases XRCC1 expression by promoting its proteasomal degradation. Black-Right-Pointing-Pointer The promotion of XRCC1 degradation by cAMP signaling system is mediated by Epac1. -- Abstract: Cyclic AMP is involved in the regulation of metabolism, gene expression, cellular growth and proliferation. Recently, the cAMP signaling system was found to modulate DNA-damaging agent-induced apoptosis by regulating the expression of Bcl-2 family proteins and inhibitors of apoptosis. Thus, we hypothesized that the cAMP signaling may modulate DNAmore » repair activity, and we investigated the effects of the cAMP signaling system on {gamma}-ray-induced DNA damage repair in lung cancer cells. Transient expression of a constitutively active mutant of stimulatory G protein (G{alpha}sQL) or treatment with forskolin, an adenylyl cyclase activator, augmented radiation-induced DNA damage and inhibited repair of the damage in H1299 lung cancer cells. Expression of G{alpha}sQL or treatment with forskolin or isoproterenol inhibited the radiation-induced expression of the XRCC1 protein, and exogenous expression of XRCC1 abolished the DNA repair-inhibiting effect of forskolin. Forskolin treatment promoted the ubiquitin and proteasome-dependent degradation of the XRCC1 protein, resulting in a significant decrease in the half-life of the protein after {gamma}-ray irradiation. The effect of forskolin on XRCC1 expression was not inhibited by PKA inhibitor, but 8-pCPT-2 Prime -O-Me-cAMP, an Epac-selective cAMP analog, increased ubiquitination of XRCC1 protein and decreased XRCC1 expression. Knockdown of Epac1 abolished the effect of 8-pCPT-2 Prime -O-Me-cAMP and restored XRCC1 protein level following {gamma}-ray irradiation. From these results, we conclude that the cAMP signaling system inhibits the repair of {gamma}-ray-induced DNA damage by promoting the ubiquitin-proteasome dependent degradation of XRCC1 in an Epac-dependent pathway in lung cancer cells.« less

Microstructure and Texture Evolution During Hot Pack Rolling of Nickel-Base Superalloys to Thin Sheet and Foil (Preprint)

DTIC Science & Technology

2011-03-01

quenching . The y’ solvus temperature (Ty’) was found to be -1150°C for alloy 5A and -1220°C for alloy 5C based on isothermal heat treatments performed in...an inert argon atmosphere followed by water quenching . Similar to conventional practices for superalloys, supersolvus hot working (at 1225°C) was...approximately five times larger than that shown in Figure 8 to provide a statistically relevant estimate, only 35 pet. of the grains in this sample were within

Robust immunity to an auxotrophic Mycobacterium bovis BCG-VLP prime-boost HIV vaccine candidate in a nonhuman primate model.

PubMed

Chege, Gerald K; Burgers, Wendy A; Stutz, Helen; Meyers, Ann E; Chapman, Rosamund; Kiravu, Agano; Bunjun, Rubina; Shephard, Enid G; Jacobs, William R; Rybicki, Edward P; Williamson, Anna-Lise

2013-05-01

We previously reported that a recombinant pantothenate auxotroph of Mycobacterium bovis BCG expressing human immunodeficiency virus type 1 (HIV-1) subtype C Gag (rBCGpan-Gag) efficiently primes the mouse immune system for a boost with a recombinant modified vaccinia virus Ankara (rMVA) vaccine. In this study, we further evaluated the immunogenicity of rBCGpan-Gag in a nonhuman primate model. Two groups of chacma baboons were primed or mock primed twice with either rBCGpan-Gag or a control BCG. Both groups were boosted with HIV-1 Pr55(gag) virus-like particles (Gag VLPs). The magnitude and breadth of HIV-specific cellular responses were measured using a gamma interferon (IFN-γ) enzyme-linked immunosorbent spot (ELISPOT) assay, and the cytokine profiles and memory phenotypes of T cells were evaluated by polychromatic flow cytometry. Gag-specific responses were detected in all animals after the second inoculation with rBCGpan-Gag. Boosting with Gag VLPs significantly increased the magnitude and breadth of the responses in the baboons that were primed with rBCGpan-Gag. These responses targeted an average of 12 Gag peptides per animal, compared to an average of 3 peptides per animal for the mock-primed controls. Robust responses of Gag-specific polyfunctional T cells capable of simultaneously producing IFN-γ, tumor necrosis alpha (TNF-α), and interleukin-2 (IL-2) were detected in the rBCGpan-Gag-primed animals. Gag-specific memory T cells were skewed toward a central memory phenotype in both CD4(+) and CD8(+) T cell populations. These data show that the rBCGpan-Gag prime and Gag VLP boost vaccine regimen is highly immunogenic, inducing a broad and polyfunctional central memory T cell response. This report further indicates the feasibility of developing a BCG-based HIV vaccine that is safe for childhood HIV immunization.

Pulsar simulations for the Fermi Large Area Telescope

DOE PAGES

Razzano, M.; Harding, Alice K.; Baldini, L.; ...

2009-05-21

Pulsars are among the prime targets for the Large Area Telescope (LAT) aboard the recently launched Fermi observatory. The LAT will study the gamma-ray Universe between 20 MeV and 300 GeV with unprecedented detail. Increasing numbers of gamma-ray pulsars are being firmly identified, yet their emission mechanisms are far from being understood. To better investigate and exploit the LAT capabilities for pulsar science, a set of new detailed pulsar simulation tools have been developed within the LAT collaboration. The structure of the pulsar simulator package ( PulsarSpectrum) is presented here. Starting from photon distributions in energy and phase obtained frommore » theoretical calculations or phenomenological considerations, gamma-rays are generated and their arrival times at the spacecraft are determined by taking into account effects such as barycentric effects and timing noise. Pulsars in binary systems also can be simulated given orbital parameters. As a result, we present how simulations can be used for generating a realistic set of gamma-rays as observed by the LAT, focusing on some case studies that show the performance of the LAT for pulsar observations.« less

Interaction with extracellular matrix proteins influences Lsh/Ity/Bcg (candidate Nramp) gene regulation of macrophage priming/activation for tumour necrosis factor-alpha and nitrite release.

PubMed

Formica, S; Roach, T I; Blackwell, J M

1994-05-01

The murine resistance gene Lsh/Ity/Bcg regulates activation of macrophages for tumour necrosis factor-alpha (TNF-alpha)-dependent production of nitric oxide mediating antimicrobial activity against Leishmania, Salmonella and Mycobacterium. As Lsh is differentially expressed in macrophages from different tissue sites, experiments were performed to determine whether interaction with extracellular matrix (ECM) proteins would influence the macrophage TNF-alpha response. Plating of bone marrow-derived macrophages onto purified fibrinogen or fibronectin-rich L929 cell-derived matrices, but not onto mannan, was itself sufficient to stimulate TNF-alpha release, with significantly higher levels released from congenic B10.L-Lshr compared to C57BL/10ScSn (Lshs) macrophages. Only macrophages plated onto fibrinogen also released measurable levels of nitrites, again higher in Lshr compared to Lshs macrophages. Addition of interferon-gamma (IFN-gamma), but not bacterial lipopolysaccharide or mycobacterial lipoarabinomannan, as a second signal enhanced the TNF-alpha and nitrite responses of macrophages plated onto fibrinogen, particularly in the Lshr macrophages. Interaction with fibrinogen and fibronectin also primed macrophages for an enhanced TNF-alpha response to leishmanial parasites, but this was only translated into enhanced nitrite responses in the presence of IFN-gamma. In these experiments, Lshr macrophages remained superior in their TNF-alpha responses throughout, but to a degree which reflected the magnitude of the difference observed on ECM alone. Hence, the specificity for the enhanced TNF-alpha responses of Lshr macrophages lay in their interaction with fibrinogen and fibronectin ECM, while a differential nitrite response was only observed with fibrinogen and/or IFN-gamma. The results are discussed in relation to the possible function of the recently cloned candidate gene Nramp, which has structural identity to eukaryote transporters and an N-terminal cytoplasmic proline/serine-rich putative SH3 binding domain.

Interferon-gamma alone triggers the production of nitric oxide from serum-starved BNL CL.2, murine embryonic liver cells.

PubMed

Pae, H O; Yoo, J C; Choi, B M; Paik, S G; Kim, Y H; Jin, H S; Chung, H T

1999-01-01

A previous study has demonstrated that both interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS) were needed to induce the production of nitric oxide (NO) in BNL CL.2 cells, murine embryonic liver cells. We here demonstrate that when BNL CL.2 cells were cultured with serum-free medium, they were induced to produce NO by the stimulation of IFN-gamma alone. BNL CL.2 cells were cultured with serum-free or serum-containing medium for 1-3 days and then stimulated to synthesize NO by IFN-gamma. Surprisingly, only serum-starved cells showed significant amount of nitrite accumulation and iNOS protein expression in response to IFN-gamma in dose- and time-dependent manners, but serum-supplied cells did not. When the cells were stimulated with IFN-gamma, tumor necrosis factor-alpha (TNF-alpha), or LPS in combinations, only the combination of IFN-gamma and LPS produced more NO than that produced by IFN-gamma alone. The production of NO by the cells stimulated with IFN-gamma or IFN-gamma plus LPS was blocked by the addition of N(G)-monomethyl-L-arginine (N(G)MMA), a NO synthesis inhibitor. To address the intracellular signal pathway responsible for the production of NO by the cells stimulated with IFN-gamma aloneor IFN-gamma plus LPS, we examined the effects of several protein kinase inhibitors on the production of NO from the cells. The production of NO was significantly inhibited by protein tyrosine kinase (PTK) inhibitors, genistein and herbimycin A, but not by protein kinase A or C inhibitors. These results suggest that the deprivation of serum from BNL CL.2 cell culture medium might prime the cells to induce NO synthesis when the cells are triggered by IFN-gamma and the involvement of PTK signal transduction pathway in the expression of inducible NO synthase gene in murine hepatoma cells.

Multimodal imaging of repetition priming: Using fMRI, MEG, and intracranial EEG to reveal spatiotemporal profiles of word processing.

PubMed

McDonald, Carrie R; Thesen, Thomas; Carlson, Chad; Blumberg, Mark; Girard, Holly M; Trongnetrpunya, Amy; Sherfey, Jason S; Devinsky, Orrin; Kuzniecky, Rubin; Dolye, Werner K; Cash, Sydney S; Leonard, Matthew K; Hagler, Donald J; Dale, Anders M; Halgren, Eric

2010-11-01

Repetition priming is a core feature of memory processing whose anatomical correlates remain poorly understood. In this study, we use advanced multimodal imaging (functional magnetic resonance imaging (fMRI) and magnetoencephalography; MEG) to investigate the spatiotemporal profile of repetition priming. We use intracranial electroencephalography (iEEG) to validate our fMRI/MEG measurements. Twelve controls completed a semantic judgment task with fMRI and MEG that included words presented once (new, 'N') and words that repeated (old, 'O'). Six patients with epilepsy completed the same task during iEEG recordings. Blood-oxygen level dependent (BOLD) responses for N vs. O words were examined across the cortical surface and within regions of interest. MEG waveforms for N vs. O words were estimated using a noise-normalized minimum norm solution, and used to interpret the timecourse of fMRI. Spatial concordance was observed between fMRI and MEG repetition effects from 350 to 450 ms within bilateral occipitotemporal and medial temporal, left prefrontal, and left posterior temporal cortex. Additionally, MEG revealed widespread sources within left temporoparietal regions, whereas fMRI revealed bilateral reductions in occipitotemporal and left superior frontal, and increases in inferior parietal, precuneus, and dorsolateral prefrontal activity. BOLD suppression in left posterior temporal, left inferior prefrontal, and right occipitotemporal cortex correlated with MEG repetition-related reductions. IEEG responses from all three regions supported the timecourse of MEG and localization of fMRI. Furthermore, iEEG decreases to repeated words were associated with decreased gamma power in several regions, providing evidence that gamma oscillations are tightly coupled to cognitive phenomena and reflect regional activations seen in the BOLD signal. Copyright 2010 Elsevier Inc. All rights reserved.

Multimodal imaging of repetition priming: Using fMRI, MEG, and intracranial EEG to reveal spatiotemporal profiles of word processing

PubMed Central

McDonald, Carrie R.; Thesen, Thomas; Carlson, Chad; Blumberg, Mark; Girard, Holly M.; Trongnetrpunya, Amy; Sherfey, Jason S.; Devinsky, Orrin; Kuzniecky, Rubin; Dolye, Werner K.; Cash, Sydney S.; Leonard, Matt K.; Hagler, Donald J.; Dale, Anders M.; Halgren, Eric

2010-01-01

Repetition priming is a core feature of memory processing whose anatomical correlates remain poorly understood. In this study, we use advanced multimodal imaging (functional magnetic resonance imaging (fMRI) and magnetoencephalography; MEG) to investigate the spatiotemporal profile of repetition priming. We use intracranial electroencephalography (iEEG) to validate our fMRI/MEG measurements. Twelve controls completed a semantic judgment task with fMRI and MEG that included words presented once (new, ‘N’) and words that repeated (old, ‘O’). Six patients with epilepsy completed the same task during iEEG recordings. Blood-oxygen level dependent (BOLD) responses for N vs O words were examined across the cortical surface and within regions of interest. MEG waveforms for N vs O words were estimated using a noise-normalized minimum norm solution, and used to interpret the timecourse of fMRI. Spatial concordance was observed between fMRI and MEG repetition effects from 350–450ms within bilateral occipitotemporal and medial temporal, left prefrontal, and left posterior temporal cortex. Additionally, MEG revealed widespread sources within left temporoparietal regions, whereas fMRI revealed bilateral reductions in occipitotemporal and left superior frontal, and increases in inferior parietal, precuneus, and dorsolateral prefrontal activity. BOLD suppression in left posterior temporal, left inferior prefrontal, and right occipitotemporal cortex correlated with MEG repetition-related reductions. IEEG responses from all three regions supported the timecourse of MEG and localization of fMRI. Furthermore, iEEG decreases to repeated words were associated with decreased gamma power in several regions, providing evidence that gamma oscillations are tightly coupled to cognitive phenomena and reflect regional activations seen in the BOLD signal. PMID:20620212

Mycobacterium leprae-Infected Macrophages Preferentially Primed Regulatory T Cell Responses and Was Associated with Lepromatous Leprosy

PubMed Central

Miranda, Jake W.; Gilson, Danny J.; Song, Zhengyu; Chen, Jia; Shi, Chao; Zhu, Jianyu; Yang, Jun; Jing, Zhichun

2016-01-01

Background The persistence of Mycobacterium leprae (M. leprae) infection is largely dependent on the types of host immune responses being induced. Macrophage, a crucial modulator of innate and adaptive immune responses, could be directly infected by M. leprae. We therefore postulated that M. leprae-infected macrophages might have altered immune functions. Methodology/Principal Findings Here, we treated monocyte-derived macrophages with live or killed M. leprae, and examined their activation status and antigen presentation. We found that macrophages treated with live M. leprae showed committed M2-like function, with decreased interleukin 1 beta (IL-1beta), IL-6, tumor necrosis factor alpha (TNF-alpha) and MHC class II molecule expression and elevated IL-10 and CD163 expression. When incubating with naive T cells, macrophages treated with live M. leprae preferentially primed regulatory T (Treg) cell responses with elevated FoxP3 and IL-10 expression, while interferon gamma (IFN-gamma) expression and CD8+ T cell cytotoxicity were reduced. Chromium release assay also found that live M. leprae-treated macrophages were more resistant to CD8+ T cell-mediated cytotoxicity than sonicated M. leprae-treated monocytes. Ex vivo studies showed that the phenotype and function of monocytes and macrophages had clear differences between L-lep and T-lep patients, consistent with the in vitro findings. Conclusions/Significance Together, our data demonstrate that M. leprae could utilize infected macrophages by two mechanisms: firstly, M. leprae-infected macrophages preferentially primed Treg but not Th1 or cytotoxic T cell responses; secondly, M. leprae-infected macrophages were more effective at evading CD8+ T cell-mediated cytotoxicity. PMID:26751388

Cross sections for the exclusive photon electroproduction on the proton and Generalized Parton Distributions

DOE PAGES

Jo, Hyon -Suk

2015-11-17

Unpolarized and beam-polarized four-fold cross sectionsmore » $$\\frac{d^4 \\sigma}{dQ^2 dx_B dt d\\phi}$$ for the $$ep\\to e^\\prime p^\\prime \\gamma$$ reaction were measured using the CLAS detector and the 5.75-GeV polarized electron beam of the Jefferson Lab accelerator, for 110 ($$Q^2,x_B,t$$) bins over the widest phase space ever explored in the valence-quark region. Several models of Generalized Parton Distributions (GPDs) describe the data well at most of our kinematics. This increases our confidence that we understand the GPD $H$, expected to be the dominant contributor to these observables. Thus, through a leading-twist extraction of Compton Form Factors, these results reveal a tomographic image of the nucleon.« less

Human Monocytes in the Presence of Interferons Alpha2a and Gamma Are Potent Killers of Serous Ovarian Cancer Cell Lines in Combination with Paclitaxel and Carboplatin

PubMed Central

Johnson, Chase L.; Zoon, Kathryn C.

2015-01-01

Interferons (IFNs) play an important role in immune surveillance of tumors; however, their efficacy in the treatment of malignancies has been limited. Monocytes are mononuclear phagocytes that are critical to the generation of an innate immune response to tumors. The authors and others have shown that treatment of tumor cell lines in vitro and in vivo with human monocytes primed with type I and type II IFNs results in killing. We now expand on this work, in an extended panel of ovarian cancer cell lines. In this study, we hypothesized that there would be variable sensitivity amongst cell lines to the killing properties of monocytes and IFNs. To this end, we explored the interactions of IFN primed monocytes in conjunction with the standard of therapy for ovarian cancer, taxane, and platinum-based chemotherapeutics. Using 6 ovarian cancer cell lines, we demonstrated that there is variation from cell line to cell line in the ability of IFN-α2a and IFN-γ primed monocytes to synergistically kill target tumor cells, and further, there is an additive killing effect when target cells are treated with both IFN primed monocytes and chemotherapy. PMID:25068849

Microstructure Evolution and Composition Control during the Processing of Thin-gage Metallic Foil (Preprint)

DTIC Science & Technology

2012-02-01

the presence of somewhat randomly-distributed carbides and borides (white particles in BSE images), this grain size was comparable to that observed...pinned by carbide/ boride particles (imaging white in Figure 8c). The very fine gamma-prime precipitates likely produced during magnetron sputtering...sputtered material. First, the carbide/ boride particles were nucleated and hence located preferentially at the grain boundaries in the sputtered

P. aeruginosa PilT Structures with and without Nucleotide Reveal a Dynamic Type IV Pilus Retraction Motor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Misic, Ana M.; Satyshur, Kenneth A.; Forest, Katrina T.

Type IV pili are bacterial extracellular filaments that can be retracted to create force and motility. Retraction is accomplished by the motor protein PilT. Crystal structures of Pseudomonas aeruginosa PilT with and without bound {beta},{gamma}-methyleneadenosine-5{prime}-triphosphate have been solved at 2.6 {angstrom} and 3.1 {angstrom} resolution, respectively, revealing an interlocking hexamer formed by the action of a crystallographic 2-fold symmetry operator on three subunits in the asymmetric unit and held together by extensive ionic interactions. The roles of two invariant carboxylates, Asp Box motif Glu163 and Walker B motif Glu204, have been assigned to Mg{sup 2+} binding and catalysis, respectively. Themore » nucleotide ligands in each of the subunits in the asymmetric unit of the {beta},{gamma}-methyleneadenosine-5{prime}-triphosphate-bound PilT are not equally well ordered. Similarly, the three subunits in the asymmetric unit of both structures exhibit differing relative conformations of the two domains. The 12{sup o} and 20{sup o} domain rotations indicate motions that occur during the ATP-coupled mechanism of the disassembly of pili into membrane-localized pilin monomers. Integrating these observations, we propose a three-state 'Ready, Active, Release' model for the action of PilT.« less

Crystallization and characterization of Y2O3-SiO2 glasses

NASA Technical Reports Server (NTRS)

Drummond, Charles H., III; Lee, William E.; Sanders, W. A.; Kiser, J. D.

1991-01-01

Glasses in the yttria-silica system with 20 to 40 mol pct Y2O3 were subjected to recrystallization studies after melting at 1900 to 2100 C in W crucibles in 1 and 50 atm N2. The TEM and XRD results obtained indicate the presence of the delta, gamma, gamma prime, and beta-Y2Si2O7 crystalline phases, depending on melting and quenching conditions. Heat treatment in air at 1100 to 1600 C increased the amount of crystallization, and led to the formation of Y2SiO5, cristabalite, and polymorphs of Y2Si2O7. Also investigated were the effects of 5 and 10 wt pct zirconia additions.

Vaccination of calves using the BRSV nucleocapsid protein in a DNA prime-protein boost strategy stimulates cell-mediated immunity and protects the lungs against BRSV replication and pathology.

PubMed

Letellier, Carine; Boxus, Mathieu; Rosar, Laurent; Toussaint, Jean-François; Walravens, Karl; Roels, Stefan; Meyer, Gilles; Letesson, Jean-Jacques; Kerkhofs, Pierre

2008-09-02

Respiratory syncytial virus (RSV) is a major cause of respiratory disease in both cattle and young children. Despite the development of vaccines against bovine (B)RSV, incomplete protection and exacerbation of subsequent RSV disease have occurred. In order to circumvent these problems, calves were vaccinated with the nucleocapsid protein, known to be a major target of CD8(+) T cells in cattle. This was performed according to a DNA prime-protein boost strategy. The results showed that DNA vaccination primed a specific T-cell-mediated response, as indicated by both a lymphoproliferative response and IFN-gamma production. These responses were enhanced after protein boost. After challenge, mock-vaccinated calves displayed gross pneumonic lesions and viral replication in the lungs. In contrast, calves vaccinated by successive administrations of plasmid DNA and protein exhibited protection against the development of pneumonic lesions and the viral replication in the BAL fluids and the lungs. The protection correlated to the cell-mediated immunity and not to the antibody response.

Observations of the Crab Nebula at energies 4.10(11)

NASA Technical Reports Server (NTRS)

Cawley, M. F.; Regan, D. J.; Gibbs, K.; Gorham, P. W.; Lamb, R. C.; Liebing, D. F.; Mackeown, P. K.; Porter, N. A.; Stenger, V. J.; Weekes, T. C.

1985-01-01

Since the development of gamma-ray astronomical telescopes, the Crab Nebula has been a prime target for observations. From 100 to 1000 MeV, the pulsar PSR0531 is the dominant source with a light-curve similar to that seen at lower energies; there is also some evidence for longterm amplitude variations but none for emission from the Nebula itself. In the very high energy gamma-ray region there have been reported detections of pulsed emission with longterm time variations from minutes to months. Recently a pulsed flux has been reported that resisted over a long time interval. The detection of a flux from the Nebula at the 3 sigma level at energies of 3x1011eV was reported; there was no evidence of periodic emissions on any time scale during the three years of observations. A new measurement of very high energy gamma rays from the Crab Nebula is reported using the imaging system on the Whipple Observatory 10m reflector.

Development and Evaluation of Wide Clearance Braze Joints in Gamma Prime Alloys.

DTIC Science & Technology

1982-03-01

from nickel base superalloys which contain significant amounts of aluminum and/or titanium . * These latter two elements, while imparting good hiqh...thermally induced tensile stress fatigue, their surfaces become covered with oxides (and sulfides) of the aluminum and titanium used to strengthen the alloys...process, it also cleans crack surfaces, and this opens a way to repair the very costly parts. Since the alloys contain aluminum and titanium , post- weld

Persistence of Protective Immunity to Malaria Induced by DNA Priming and Poxvirus Boosting: Characterization of Effector and Memory CD8+-T-Cell Populations

PubMed Central

Sedegah, Martha; Brice, Gary T.; Rogers, William O.; Doolan, Denise L.; Charoenvit, Yupin; Jones, Trevor R.; Majam, Victoria F.; Belmonte, Arnel; Lu, Minh; Belmonte, Maria; Carucci, Daniel J.; Hoffman, Stephen L.

2002-01-01

The persistence of immunity to malaria induced in mice by a heterologous DNA priming and poxvirus boosting regimen was characterized. Mice were immunized by priming with DNA vaccine plasmids encoding the Plasmodium yoelii circumsporozoite protein (PyCSP) and murine granulocyte-macrophage colony-stimulating factor and boosting with recombinant vaccinia encoding PyCSP. BALB/c mice immunized with either high-dose (100 μg of p PyCSP plus 30 μg of pGM-CSF) or low-dose (1 μg of p PyCSP plus 1 μg of pGM-CSF DNA) priming were protected against challenge with 50 P. yoelii sporozoites. Protection 2 weeks after immunization was 70 to 100%, persisted at this level for at least 20 weeks, and declined to 30 to 40% by 28 weeks. Eight of eight mice protected at 20 weeks were still protected when rechallenged at 40 weeks. The antigen (Ag)-specific effector CD8+-T-cell population present 2 weeks after boosting had ex vivo Ag-specific cytolytic activity, expressed both gamma interferon (IFN-γ) and tumor necrosis factor alpha, and constituted 12 to 20% of splenic CD8+ T cells. In contrast, the memory CD8+-Ag-specific-cell population at 28 weeks lacked cytolytic activity and constituted only 6% of splenic CD8+ T cells, but at the single-cell level it produced significantly higher levels of IFN-γ than the effectors. High levels of Ag- or parasite-specific antibodies present 2 weeks after boosting had declined three- to sevenfold by 28 weeks. Low-dose priming was similarly immunogenic and as protective as high-dose priming against a 50-, but not a 250-, sporozoite challenge. These results demonstrate that a heterologous priming and boosting vaccination can provide lasting protection against malaria in this model system. PMID:12065488

Deep H.E.S.S. observations of the supernova remnant RX J0852.0-4622

NASA Astrophysics Data System (ADS)

Sushch, Iurii; Paz Arribas, Manuel; Komin, Nukri; Schwanke, Ullrich

2016-06-01

The largest TeV source, RX J0852.0-4622 (Vela Jr.), is one of the few supernova remnants (SNRs) with well resolved shell-like morphology at very-high-energy (VHE; E>100 GeV) gamma-rays. Strong non-thermal emission across the electromagnetic spectrum from radio to VHE gamma-rays, young age and proximity of the remnant makes it one of the prime objects for the study of particle acceleration aiming to test the paradigm of SNRs being sources of Galactic cosmic rays. Here we present deep H.E.S.S. observations of RX J0852.0-4622 with roughly doubled exposure comparing to previously published results. Improved statistics together with new analysis techniques result in a firm determination of the cut-off in the gamma-ray spectrum and allow the spatially resolved spectroscopy studies. A smooth connection of the H.E.S.S. spectrum to the spectrum at GeV energies as reported by Fermi/LAT provides an exciting opportunity to recover the present-time parent particle population in both leptonic and hadronic scenarios directly from the gamma-ray data alone. These new observations provide us a deeper insight and better understanding of the physical processes in SNRs.

{ital W}-pair production in the process {ital e}{sup +}{ital e}{sup {minus}}{r_arrow}{ital l}{nu}{ital q{bar q}}{prime} and measurement of the {ital WW}{gamma} and {ital WWZ} couplings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gintner, M.; Godfrey, S.; Couture, G.

1995-12-01

We perform a detailed analysis of the process {ital e}{sup +}{ital e}{sup {minus}}{r_arrow}{ital l}{nu}{ital q{bar q}}{prime} where we include all tree level Feynman diagrams that contribute to this final state. We study the sensitivity of this process to anomalous trilinear gauge boson couplings of the {ital WW}{gamma} and {ital WWZ} vertices using two popular parametrizations. We use a maximum likelihood analysis of a five-dimensional differential cross section based on the {ital W} and {ital W} decay product angular distributions. We concentrate on CERN LEP 200 energies, taking {radical}{ital s} =175 GeV, and energies appropriate to the proposed Next Linear Collider,more » a high energy {ital e}{sup +}{ital e}{sup {minus}} collider with center-of-mass energies {radical}{ital s} =500 and 1 TeV. At 175 GeV, {ital g}{sub 1}{sup {ital Z}} can be measured to about {plus_minus}0.2, {kappa}{sub {ital Z}} to {plus_minus}0.2, and {kappa}{sub {gamma}} to {plus_minus}0.3 {lambda}{sub {ital Z}} to {plus_minus}0.2 and {lambda}{sub {gamma}} to {plus_minus}0.3 at 95% C.L. assuming 500 pb{sup {minus}1} integrated luminosity. Although these will be improvements of existing measurements they are not sufficiently precise to test the standard model at the loop level and are unlikely to see deviations from SM expectations. At 500 GeV with 50 fb{sup {minus}1} integrated luminosity, {ital g}{sub 1}{sup {ital Z}} can be measured to about {plus_minus}0.01, {kappa}{sub {ital Z}} and {kappa}{sub {gamma}} to {plus_minus}0.005 and {lambda}{sub {ital Z}} and {lambda}{sub {gamma}} to {plus_minus}0.003 at 95% C.L. while at 1 TeV with 200 fb{sup {minus}1} integrated luminosity, {kappa}{sub {ital V}} and {lambda}{sub {ital V}} can be measured to about {plus_minus}0.005 and {plus_minus}10{sup {minus}3}, respectively. The 500 GeV measurements will be at the level of loop contributions to the couplings and may show hints of new physics while the 1 TeV should be sensitive to new physics at the loop level.« less

Protracted low-dose radiation priming and response of liver to acute gamma and proton radiation.

PubMed

Gridley, D S; Mao, X W; Cao, J D; Bayeta, E J M; Pecaut, M J

2013-10-01

This study evaluated liver from C57BL/6 mice irradiated with low-dose/low-dose-rate (LDR) γ-rays (0.01 Gy, 0.03 cGy/h), with and without subsequent exposure to acute 2 Gy gamma or proton radiation. Analyses were performed on day 56 post-exposure. Expression patterns of apoptosis-related genes were strikingly different among irradiated groups compared with 0 Gy (p < 0.05). Two genes were affected in the Gamma group, whereas 10 were modified in the LDR + Gamma group. In Proton and LDR + Proton groups, there were six and 12 affected genes, respectively. Expression of genes in the Gamma (Traf3) and Proton (Bak1, Birc2, Birc3, Mcl1) groups was no longer different from 0 Gy control group when mice were pre-exposed to LDR γ-rays. When each combined regimen was compared with the corresponding group that received acute radiation alone, two genes in the LDR + Gamma group and 17 genes in the LDR + Proton group were modified; greatest effect was on Birc2 and Nol3 (> 5-fold up-regulated by LDR + Protons). Oxygen radical production in livers from the LDR + Proton group was higher in LDR, Gamma, and LDR + Gamma groups (p < 0.05 vs. 0 Gy), but there were no differences in phagocytosis of E. coli. Sections stained with hematoxylin and eosin (H&E) suggested more inflammation, with and without necrosis, in some irradiated groups. The data demonstrate that response to acute radiation is dependent on radiation quality and regimen and that some LDR γ-ray-induced modifications in liver response were still evident nearly 2 months after exposure.

Interferon-alpha and interferon-gamma sensitize human tenon fibroblasts to mitomycin-C.

PubMed

Wang, Xiao Yang; Crowston, Jonathan G; Zoellner, Hans; Healey, Paul R

2007-08-01

To investigate the effect of interferon (IFN)-alpha and IFN-gamma pretreatment on mitomycin C (MMC)-induced cell death in human Tenon fibroblasts (HTFs) and the mechanisms by which IFN-alpha and IFN-gamma modulate the susceptibility of HTFs to MMC. HTFs were pretreated with IFN-alpha and IFN-gamma for 48 hours before 5-minute application of 0.4 mg/mL MMC. Cell death after 48 hours was determined by Annexin V/propidium iodide (PI) staining and lactate dehydrogenase (LDH) release assay. Fas, Fas-ligand, and Bcl-2 expression were determined by flow cytometry. Fas associated death domain (FADD), Bax, cytochrome c, and caspase expression were determined by Western blot analysis and immunofluorescence staining. MMC treatment increased cell death and upregulated Fas and FADD expression, but had no effect on Fas-Ligand, Bax, Bcl-2, or cytochrome c. Neither IFN-alpha nor IFN-gamma alone induced HTF death, but each increased cell death 2 days after MMC treatment in a dose-dependent fashion. Combination IFN-alpha and IFN-gamma had a synergistic effect. IFN-alpha and IFN-gamma pretreatment increased Fas expression. Fas upregulation was associated with increased sensitivity to MMC. IFN pretreatment increased procaspase-8, procaspase-9, and procaspase-3 expression, and caspase-3 activation. Caspase-8, caspase-3, and broad caspase inhibitors, but not caspase-9 inhibitor, inhibited MMC-induced cell death in nonpretreated and IFN-pretreated cells. IFN-alpha and IFN-gamma enhance the susceptibility of HTFs to MMC-induced cell death through a Fas-mediated and a caspase-3-dependent pathway. Pretreatment with IFN primed HTFs to MMC, providing a potential means for initially slowing the healing response with IFN and subsequently terminating fibroblast activity through MMC-induced cell death.

Defense Small Business Innovation Research Program (SBIR). Volume 3. Air Force Abstracts of Phase 1 Awards 1987.

DTIC Science & Technology

1988-04-01

RESISTANCE, AS WELL AS GUIDELINES FROM APPROPRIATE AEROSPACE SPECIFICATIONS; MATERIALS WILL INCLUDE ALUMINUM AND TITANIUM ALLOYS, PLUS A FEW STEELS...VAPOR SYNTHESIS OF NIOBIUM ALUMINIDES TOPIC# 105 OFFICE: AFWAL/ML DIRECT SYNTHESIS OF NbA1 ALLOY FOILS BY CHEMICAL VAPOR DEPOSITION ONTO INERT SUBSTRATES...GROWT OF GAMMA PRIME NICKEL ALUMINIDE (Ni3AI) %% TOPICt 104 OFFICE: AFWAL/ML . SMALL BUSINESS INNOVATION RESEARCH (SBIR) PROGRAM - PHASE 1 PAGE 555

Mechanisms of Precipitation of Different Generations of Gamma-Prime Precipitates During Continuous Cooling of a Nickel Base Superalloy (PREPRINT)

DTIC Science & Technology

2012-08-01

processed through the powder metallurgy route and develops a polycrystalline microstructure consisting of γ grains with nanoscale γ’ precipitates...on the cooling rate employed. Faster cooling rates, such as those encountered during water quenching the alloy from the high temperature single γ...and the first generation γ’ precipitates. Subsequently on quenching to a lower temperature a second generation of γ’ precipitates are formed that are

Fundamental Studies of Strengthening Mechanisms in Metals Using Dislocation Dynamics

DTIC Science & Technology

2006-03-26

to quantify the elastic fields of inclusion eigenstrain problems in 2D and 3D (Lerma et al. 2003). The inclusions can be of any shape or size and the... eigenstrains can be arbitrarily assigned, i.e. constant or non-constant within the inclusion. The method works well for material or field points...geometry and misfits. Recently, we have developed a new distributed-dislocation method for modeling eigenstrain problems such as gamma prime inclusions

Compton Gamma Ray Observatory: Lessons Learned in Propulsion

NASA Technical Reports Server (NTRS)

Dressler, G. A.; Joseph, G. W.; Behrens, H. W.; Asato, D. I.; Carlson, R. A.; Bauer, Frank H. (Technical Monitor)

2001-01-01

The Compton Gamma Ray Observatory was the second of NASA's Great Observatories. At 17 1/2 tons. it was the heaviest astrophysical payload ever flown at the time of its launch on April 5, 1991 aboard the Space Shuttle. During initial, on-orbit priming of the spacecraft's monopropellant hydrazine propulsion system, a severe waterhammer transient was experienced. At that time, anomalous telemetry readings were received from on-board propulsion system instrumentation. This led to ground analyses and laboratory investigations as to the root cause of the waterhammer, potential damage to system integrity and functionality, and risks for switching from the primary (A-side) propulsion system to the redundant (B-side) system. The switchover to B-side was ultimately performed successfully and the spacecraft completed its basic and extended missions in this configuration. Nine years later, following a critical control gyroscope failure, Compton was safely deorbited and re-entered the Earth's atmosphere on June 4, 2000. Additional risk assessments concerning viability of A- and B-sides were necessary to provide confidence in attitude and delta-V authority and reliability to manage the precisely controlled reentry. This paper summarizes the design and operation of the propulsion system used on the spacecraft and provides "lessons learned" from the system engineering investigations into the propellant loading procedures, the initial priming anomaly, mission operations, and the commanded re-entry following the gyro failure.

Average structure and M2 site configurations in C2/c clinopyroxenes along the Di-En join

NASA Astrophysics Data System (ADS)

Tribaudino, M.; Benna, P.; Bruno, E.

1989-12-01

In order to clarify the structural configurations observed in Diss in the Ca-rich region of the Di-En join (in which TEM observations show neither exsolution microstructures nor evidence of spinodal decomposition) single crystals large enough for X-ray diffraction analyses, with composition (Ca0.66Mg0.34)MgSi2O6, have been equilibrated close to the solvus at T=1350° C for 317 h, and quenched at room temperature. The refinement in C2/c space group shows that in the M2 site Ca and Mg are fully ‘ordered’ in two split positions (M2occ: 0.66 Ca; M2'occ: 0.34 Mg). Since the average structure shows a relevant elongation of anisotropic thermal ellipsoids of the O2 and O3 oxygen atoms, the refinement has been carried out according to a split model for O2 and O3 atoms: Ca appears 8-coordinated (as in diopside) and Mg shows a sixfold coordination similar to that of high-pigeonite. This coordination for Mg is significantly different from the fourfold coordination (Zn-like in Zn-cpx) proposed previously and it is a more probable coordination for Mg from a crystalchemical point of view. The same results were obtained refining a Di80En20 cpx, equilibrated at T=1230° C, according to the same O-split model. The data support the coexistence of a Di-like configuration for Ca and of a highPig-like configuration for Mg away from the solvus also. At T very near to T solidus the different configurations, observed at room temperature in the quenched samples, should converge and Ca and Mg should retain a single disordered configuration in the M2 site.

Neural correlates of cross-modal affective priming by music in Williams syndrome.

PubMed

Lense, Miriam D; Gordon, Reyna L; Key, Alexandra P F; Dykens, Elisabeth M

2014-04-01

Emotional connection is the main reason people engage with music, and the emotional features of music can influence processing in other domains. Williams syndrome (WS) is a neurodevelopmental genetic disorder where musicality and sociability are prominent aspects of the phenotype. This study examined oscillatory brain activity during a musical affective priming paradigm. Participants with WS and age-matched typically developing controls heard brief emotional musical excerpts or emotionally neutral sounds and then reported the emotional valence (happy/sad) of subsequently presented faces. Participants with WS demonstrated greater evoked fronto-central alpha activity to the happy vs sad musical excerpts. The size of these alpha effects correlated with parent-reported emotional reactivity to music. Although participant groups did not differ in accuracy of identifying facial emotions, reaction time data revealed a music priming effect only in persons with WS, who responded faster when the face matched the emotional valence of the preceding musical excerpt vs when the valence differed. Matching emotional valence was also associated with greater evoked gamma activity thought to reflect cross-modal integration. This effect was not present in controls. The results suggest a specific connection between music and socioemotional processing and have implications for clinical and educational approaches for WS.

EV02: a Phase I trial to compare the safety and immunogenicity of HIV DNA-C prime-NYVAC-C boost to NYVAC-C alone.

PubMed

McCormack, Sheena; Stöhr, Wolfgang; Barber, Tristan; Bart, Pierre-Alexandre; Harari, Alexandre; Moog, Christiane; Ciuffreda, Donatella; Cellerai, Cristina; Cowen, Miranda; Gamboni, Romilda; Burnet, Séverine; Legg, Ken; Brodnicki, Elizabeth; Wolf, Hans; Wagner, Ralf; Heeney, Jonathan; Frachette, Marie-Joëlle; Tartaglia, Jim; Babiker, Abdel; Pantaleo, Giuseppe; Weber, Jonathan

2008-06-13

The aim of this randomised controlled trial was to see if the addition of 4 mg/ml DNA-C priming given by the intramuscular route at weeks 0 and 4 to NYVAC-C at weeks 20 and 24, safely increased the proportion of participants with HIV-specific T-cell responses measured by the interferon (IFN)-gamma ELISpot assay at weeks 26 and/or 28 compared to NYVAC-C alone. Although 2 individuals discontinued after the first DNA-C due to adverse events (1 vaso-vagal; 1 transient, asymptomatic elevation in alanine transaminase), the vaccines were well tolerated. Three others failed to complete the regimen (1 changed her mind; 2 lost to follow-up). Of the 35 that completed the regimen 90% (18/20) in the DNA-C group had ELISpot responses compared to 33% (5/15) that received NYVAC-C alone (p=0.001). Responses were to envelope in the majority (21/23). Of the 9 individuals with responses to envelope and other peptides, 8 were in the DNA-C group. These promising results suggest that DNA-C was an effective priming agent, that merits further investigation.

Recombinant low-seroprevalent adenoviral vectors Ad26 and Ad35 expressing the respiratory syncytial virus (RSV) fusion protein induce protective immunity against RSV infection in cotton rats.

PubMed

Widjojoatmodjo, Myra N; Bogaert, Lies; Meek, Bob; Zahn, Roland; Vellinga, Jort; Custers, Jerome; Serroyen, Jan; Radošević, Katarina; Schuitemaker, Hanneke

2015-10-05

RSV is an important cause of lower respiratory tract infections in children, the elderly and in those with underlying medical conditions. Although the high disease burden indicates an urgent need for a vaccine against RSV, no licensed RSV vaccine is currently available. We developed an RSV vaccine candidate based on the low-seroprevalent human adenovirus serotypes 26 and 35 (Ad26 and Ad35) encoding the RSV fusion (F) gene. Single immunization of mice with either one of these vectors induced high titers of RSV neutralizing antibodies and high levels of F specific interferon-gamma-producing T cells. A Th1-type immune response was indicated by a high IgG2a/IgG1 ratio of RSV-specific antibodies, strong induction of RSV-specific interferon-gamma and tumor necrosis factor-alpha cytokine producing CD8 Tcells, and low RSV-specific CD4 T-cell induction. Both humoral and cellular responses were increased upon a boost with RSV-F expressing heterologous adenovirus vector (Ad35 boost after Ad26 prime or vice versa). Both single immunization and prime-boost immunization of cotton rats induced high and long-lasting RSV neutralizing antibody titers and protective immunity against lung and nasal RSV A2 virus load up to at least 30 weeks after immunization. Cotton rats were also completely protected against challenge with a RSV B strain (B15/97) after heterologous prime-boost immunization. Lungs from vaccinated animals showed minimal damage or inflammatory infiltrates post-challenge, in contrast to animals vaccinated with formalin-inactivated virus. Our results suggest that recombinant human adenoviral Ad26 and Ad35 vectors encoding the RSV F gene have the potential to provide broad and durable protection against RSV in humans, and appear safe to be investigated in infants. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Mechanical, Corrosion, and Fatigue Properties of 15-5 PH, Inconel 718, and Rene 41 Weldments

DTIC Science & Technology

1975-05-01

TUCUMvARI (PGH 2) It was originally developed for high - temperature use by Armco Steel Corporation. 2 High strength is obtained by the precipitation...Rene 41 was developed by General Electric Company as a high - temperature turbine alloy. It is a nickel-base alloy, high in chromium, cobalt, and... molybdenum . Its high strength comes from the precipitation of a gamma-prime phase consisting of Ni3AI and Ni5Ti, and from the solid solution effects of

Immunogenicity and protective efficacy of heterologous prime-boost regimens with mycobacterial vaccines and recombinant adenovirus- and poxvirus-vectored vaccines against murine tuberculosis.

PubMed

You, Qingrui; Wu, Yongge; Wu, Yang; Wei, Wei; Wang, Changyong; Jiang, Dehua; Yu, Xianghui; Zhang, Xizhen; Wang, Yong; Tang, Zhijiao; Jiang, Chunlai; Kong, Wei

2012-11-01

To evaluate regimens using bacillus Calmette-Guérin (BCG) or recombinant BCG (rBCG) overexpressing Ag85B for priming, followed by boosting with a modified vaccinia virus Ankara strain (MVA) and/or adenovirus vector (AD) expressing an Ag85B-ESAT6 fusion protein. Cellular and humoral immune responses were determined after subcutaneous vaccination, which was employed to trigger systemic immunity against intravenous infection in a mouse model of tuberculosis (TB). Bacterial loads and lung histology were evaluated. The relative IgG2a and IgG1 antibody levels indicated that the viral-vectored vaccines generated a T-helper type 1 (Th1)-biased response after two doses of viral boost vaccinations. Boosting BCG-primed mice with viral vaccines induced a Th1 immune response that included both CD4 and CD8 T-cells generating antigen-specific interferon-gamma (IFN-γ) and CD8 T cytotoxic activity. Only mice vaccinated with two different viral boosters after BCG priming exhibited a significant reduction in bacterial burden in the lung after challenge. Histology examinations confirmed the attenuation of lung damage and more compact granulomas. After mycobacteria priming, boosting with AD85B-E6 followed by MVA85B-E6 afforded better protection than the reverse order of administration of the viral vectors. This study demonstrates the potential of multiple heterologous viral booster vaccines, although the exact correlates of protection and optimal regimens should be further investigated for the rational design of future vaccine strategies. Copyright © 2012 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Mesenchymal Stromal Cells Prevent Allostimulation In Vivo and Control Checkpoints of Th1 Priming: Migration of Human DC to Lymph Nodes and NK Cell Activation.

PubMed

Consentius, C; Akyüz, L; Schmidt-Lucke, J A; Tschöpe, C; Pinzur, L; Ofir, R; Reinke, P; Volk, H-D; Juelke, K

2015-10-01

Although the immunomodulatory potency of mesenchymal stromal cells (MSC) is well established, the mechanisms behind are still not clear. The crosstalk between myeloid dendritic cells (mDC) and natural killer (NK) cells and especially NK cell-derived interferon-gamma (IFN-γ) play a pivotal role in the development of type 1 helper (Th1) cell immune responses. While many studies explored the isolated impact of MSC on either in vitro generated DC, NK, or T cells, there are only few data available on the complex interplay between these cells. Here, we investigated the impact of MSC on the functionality of human mDC and the consequences for NK cell and Th1 priming in vitro and in vivo. In critical limb ischemia patients, who have been treated with allogeneic placenta-derived mesenchymal-like stromal cells (PLX-PAD), no in vivo priming of Th1 responses toward the major histocompatibility complex (MHC) mismatches could be detected. Further in vitro studies revealed that mDC reprogramming could play a central role for these effects. Following crosstalk with MSC, activated mDC acquired a tolerogenic phenotype characterized by reduced migration toward CCR7 ligand and impaired ability to stimulate NK cell-derived IFN-γ production. These effects, which were strongly related to an altered interleukin (IL)-12/IL-10 production by mDC, were accompanied by an effective prevention of Th1 priming in vivo. Our findings provide novel evidence for the regulation of Th1 priming by MSC via modulation of mDC and NK cell crosstalk and show that off-the-shelf produced MHC-mismatched PLX-PAD can be used in patients without any sign of immunogenicity. © 2015 AlphaMed Press.

Epstein-Barr virus-transformed B-cells as efficient antigen presenting cells to propagate Aspergillus-specific cytotoxic T-lymphocytes.

PubMed

Ramadan, Gamal

2008-01-01

To overcome the cytotoxic T-lymphocytes (CTL) expansion limitations imposed by the lack of sufficient dendritic cells (DC) alternative sources of autologous antigen presenting cells (APC) such as Epstein-Barr virus (EBV)-transformed B-lymphoblastoid cell lines (BLCL), which are easy to establish in vitro, have been considered and studied in the present work. Non-adherent peripheral blood mononuclear cells of three healthy donors were repeatedly primed with autologous Aspergillus fumigatus commercial culture-filtrate antigen-pulsed fast monocyte-derived DC (Aspf-CFA-DC) alone, Aspf-CFA-pulsed BLCL (Aspf-CFA-BLCL) alone or Aspf-CFA-BLCL after one, two, or three primings with Aspf-CFA-DC (1DC/BLCL, 2DC/BLCL or 3DCIBLCL; respectively). After 5th priming, lines generated by Aspf-CFA-BLCL only showed strong/weak lytic activity for EBV/Aspf; respectively. Aspf-specific lytic activity in all donors was increased by increasing the number of primings with Aspf-CFA-DC before switching to Aspf-CFA-BLCL (18.20 +/- 1.65% versus 35.67 +/- 1.02% and 40.03 +/- 1.41% in bulk cultures generated by 1DC/BLCL versus 2DC/BLCL and 3DC/BLCL, respectively). Bulk cultures generated by Aspf-CFA-BLCL after at least two primings with Aspf-CFA-DC showed approximately the same Aspf-specific lytic activity, effector cell phenotype, expansion level and percentage expression of IFN-gamma, CD69 and CD107a without any significant differences (p > 0.05) as standard bulk cultures generated by only Aspf-CFA-DC. Thus, this study explored the use of a combined DC/BLCL protocol to establish/propagate Aspf-specific CTL for adoptive immunotherapy to prevent or treat invasive pulmonary aspergillosis.

Functional heterogeneity of memory B lymphocytes: in vivo analysis of TD-primed B cells responsive to secondary stimulation with TD and TI antigens.

PubMed

Rennick, D M; Morrow, P R; Benjamini, E

1983-08-01

The functional heterogeneity of memory B cells induced by a single determinant, consisting of a decapeptide representing amino acid residues 103-112 of tobacco mosaic virus protein (TMVP), was analyzed. Decapeptide specific antibodies were elicited in mice adoptively transferred with TMVP-immune spleen cells when challenged with TMVP, decapeptide conjugated to succinylated human gamma-globulin (SHGG), or decapeptide conjugated to Brucella abortus (BA). Whereas secondary stimulation by either TMVP or decapeptide-SHGG was dependent on appropriately primed T cells, stimulation by decapeptide-BA was independent of conventional T cell help. Furthermore, memory B cells responsive to TMVP (TD), decapeptide-SHGG (TD), or decapeptide-BA (TI. 1 prototype) were shown to consist of overlapping populations because adoptive recipients of TMVP-primed cells challenged simultaneously with TD and TI decapeptide antigens did not result in a higher antibody response than that elicited by one of the TD antigens injected alone. However, decapeptide-BA consistently induced a smaller antidecapeptide response than either TMVP or decapeptide-SHGG. This suggested that only a fraction of the memory B cell population which was activated by the original priming antigen (thymus-dependent) was also responsive to secondary in vivo stimulation by the priming hapten conjugated to Brucella abortus. Detailed analyses of the antibodies induced in the recipients of TMVP-immune spleen cells after secondary challenge with either TMVP, decapeptide-SHGG, or decapeptide-BA failed to distinguish between the responsive memory B cells; the antidecapeptide antibodies induced by all three immunogens shared the same fine specificities and immunoglobulin isotype composition. These data are viewed as further evidence that subsets of TD-primed B cells, which may display differential sensitivity to cross-stimulation with TD and TI forms of the antigen, represent distinct stages of memory B cell maturation within a common B cell lineage. In support of this conclusion, we establish a developmental relationship between TI and/or TD responsive decapeptide memory B cell in the following communication.

Long term monitoring of Gamma-Ray emission from the BL Lacertae object (1ES 2200+420)

NASA Astrophysics Data System (ADS)

Gunawardhana, Isuru; VERITAS Collaboration

2016-03-01

Blazars are a class of Active Galactic Nuclei (AGN) that have relativistic jets pointing along the observer line of sight. Blazars exhibit variable emission extending from radio to TeV energies. The variability timescale of the TeV flux is a key component of understanding the location of the very high energy emission zones. Deep observations of the quiescent state measurements are also required to disentangle the flaring state emission from quiescent state emission, a prerequisite for understanding the origin of blazar spectral variability. BL Lacertae (also known as 1ES 2200+420), as the namesake for all BL Lac objects, is a prime example of one such blazar. The VERITAS Observatory, an Imaging Atmospheric Cherenkov Telescope (IACT) array sensitive to gamma rays in the range from 85 GeV to 30 TeV, dedicates approximately 110 hours per year on deep observations of known gamma-ray blazars. In this talk, I will describe the TeV photon flux variability of BL Lacertae measured by VERITAS from 2013 to 2015.

Physical Metallurgy of Rene 65, a Next-Generation Cast and Wrought Nickel Superalloy for use in Aero Engine Components

NASA Astrophysics Data System (ADS)

Wessman, Andrew Ezekiel

Advancements in the design of turbine engines are in large part made possible by advancements in the capability of nickel based superalloys. Greater temperature and stress capabilities in these materials allow for increased operating temperatures and speeds in the engines, which lead to increased fuel efficiency. Early jet engines were built using austenitic stainless steels, and moved to cast and wrought nickel alloys as higher temperatures were required. By the 1970s, the state of the art nickel superalloy was Inconel 718, which is strengthened by the Ni3Nb phase known as gamma double prime. This alloy performs well and is still in heavy use in turbine engines at temperatures up to approximately 650°C (1200°F), but at higher temperatures the main strengthening precipitate phase, gamma', is thermodynamically unstable, resulting in a loss of strength following exposure to high temperature. Further advancements in nickel superalloys generally involved alloys strengthened by the Ni3Al phase known as gamma'. This precipitate is stable at much higher temperatures, but due to compositional segregation in cast and wrought processing, these alloys were processed using powder metallurgy methods, at considerable economic cost. This study will examine the microstructure of a next generation cast and wrought nickel superalloy that can provide increased temperature capability relative to Inconel 718, at lower cost than powder metallurgy superalloys. The alloy chemistry is similar to that of the powder metallurgy superalloy Rene 88DT, with changes to make it better suited for cast and wrought processing and with a different processing route from billet processing through to final part heat treatment. It is a gamma prime strengthened superalloy. The alloy has been recently introduced into service in turbine engines by GE Aviation as the alloy Rene 65, the composition of which is shown below. In this work, the following has been shown: • Rene 65 gamma' precipitate structure is related to thermal history of the material, and the particle size distribution can be predicted using established models for precipitation in superalloys. • Rene 65 shows a predictable microstructural response to high temperature exposure, with gamma' coarsening that is predictable using the Lifshitz-Slyozov-Wagner theory. • Rene 65 tensile and creep capability are determined by the gamma' distribution, and the yield strength of the alloy can be predicted using a critical resolved shear stress approach. • This work has also provided a comprehensive overview of the structure of Rene 65 during various processing stages and following thermal exposures expected during use of the alloy in turbine engines. The processing-structure-property relationships for this advanced cast and wrought nickel based superalloy developed for use in turbine engine applications are described in detail, which will serve as a useful guide in the manufacture and use of components made from the alloy, and contribute to the overall body of knowledge in the field of metallurgy of nickel based superalloys.

The immunomodulatory function of equine MSCs is enhanced by priming through an inflammatory microenvironment or TLR3 ligand.

PubMed

Cassano, Jennifer M; Schnabel, Lauren V; Goodale, Margaret B; Fortier, Lisa A

2018-01-01

Mesenchymal stem cells (MSCs) have the therapeutic potential to treat a variety of inflammatory and degenerative disease processes, however the effects of the tissue environment on MSCs have been overlooked. Our hypothesis was that the immunomodulatory function of MSCs would be impaired by TLR4 stimulation or exposure to inflammatory macrophages, whereas their immunosuppressive properties would be enhanced by TLR3 stimulation. MSCs were exposed to polyinosinic:polycytidylic acid (poly I:C) to stimulate TLR3 receptors or lipopolysaccharide (LPS) to stimulate TLR4 receptors. MSC1 proinflammatory phenotype in human MSCs was associated with increased IL-6 and IL-8 and MSC2 regenerative phenotype was associated with increased CCL2 and CXCL10. MSC immunomodulatory function was assessed by measuring the ability of primed MSCs to suppress mitogen-stimulated T cell proliferation. Peripheral blood monocytes were isolated using CD14 MACs positive selection, differentiated into macrophages, and polarized using interferon-gamma (IFN-γ). Polarization was confirmed by increased gene expression of TNFα, CCL2, and CXCL10. Inflammatory macrophages were co-cultured with MSCs for 6h, and the resultant MSC phenotype was analyzed as described above. Both TLR3 and TLR4 priming and co-culture of MSCs with inflammatory macrophages resulted in increased expression of IL-6, CCL2, and CXCL10 in MSCs. Both TLR3 and TLR4 priming or exposure of MSCs to inflammatory macrophages significantly (p<0.05) enhanced their immunomodulatory function, demonstrated by a decrease in T cell proliferation in the presence of poly I:C primed MSCs (11%), LPS primed MSCs (7%), or MSCs exposed to inflammatory macrophages (12%), compared to unstimulated MSCs. Additionally, MHC class II positive MSCs tended to have a greater magnitude of response to priming compared to MHC class II negative MSCs. These results suggest that MSCs can be activated by a variety of inflammatory stimuli, but the recipient injured tissue bed in chronic injuries may not contain sufficient inflammatory signals to activate MSC immunomodulatory function. Enhancement of MSCs immunomodulatory function through inflammatory priming prior to clinical application might improve the therapeutic effect of MSC treatments. Copyright © 2017 Elsevier B.V. All rights reserved.

Organochlorine pesticides and PCBs in human adipose tissues in Poland

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ludwicki, J.K.; Goralczyk, K.

1994-03-01

Most of the persistent organochlorine (OC) pesticides, excluding lindane, were banned in Poland in 1975/76. The first restrictions concerning the use and marketing of lindane (gamma-HCH) became effective in 1980 and were gradually extended until it's agricultural use was ultimately banned in 1989. Unfortunately, there are no detailed data on the use and release of PCBs to the environment in Poland. The former studies showed that in the late seventies the concentrations of OC pesticides and their metabolites in men reached considerable high levels. Despite of the restrictions or bans of these pesticides in most of the countries of themore » temperate climate, they still circulate in various food chains and eventually concentrate in man. Many authors claim an uneven distribution of the OC compounds in the population and report different levels in men and women and also some relations between OC compounds levels in fat tissues and age. Environmental contamination also plays an important role in the magnitude of OC compounds levels in man. The aim of this paper is to present the actual concentrations of HCB, p,p[prime]-DDT, p,p[prime]-DDE, isomers of HCH (alpha, beta, gamma), and PCBs in human adipose tissues particularly regarding age and sex as possible factors influencing the levels of these compounds and to contribute to the general discussion on the distribution patterns of the organochlorine compounds in the population. 12 refs., 3 tabs.« less

Effect of boron and carbon addition on microstructure and mechanical properties of the aged gamma-prime strengthened alumina-forming austenitic alloys [Effect of boron and carbon addition on microstructure and mechanical properties of the aged gamma-prime alumina-forming austenitic alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Bin; Trotter, Geneva; Wang, Zhangwei

Here, the goal of this work was to understand the effects of aging at 800 °C on the microstructures and mechanical properties of two recently-developed AFA stainless steels based on Fe-14Cr-32Ni-3Nb-3Al-2Ti (wt.%), one of which contained small additions of boron and carbon. To that end both the size distributions and growth kinetics of the B2, Laves phase, L1 2 precipitates present were quantified. While the lattice parameter, morphology, size and coarsening behavior of the L1 2 precipitates was the same in both AFA alloys, the B and C enhanced the grain boundary coverage by both Laves phase and B2-NiAl precipitates,more » but suppressed their coarsening. These interstitial additions also suppressed the formation of twins and discontinuous precipitation, which were observed in the B and C-free material. It is shown that the yield strength at 700 °C is largely controlled by the size of the L1 2 precipitates, with the largest strengthening effect obtained after aging for 2.4 h for both AFA alloys. Longer aging time led to a loss of strength mainly due to the coarsening of the L1 2 precipitates.« less

Additive Manufacturing of IN100 Superalloy Through Scanning Laser Epitaxy for Turbine Engine Hot-Section Component Repair: Process Development, Modeling, Microstructural Characterization, and Process Control

NASA Astrophysics Data System (ADS)

Acharya, Ranadip; Das, Suman

2015-09-01

This article describes additive manufacturing (AM) of IN100, a high gamma-prime nickel-based superalloy, through scanning laser epitaxy (SLE), aimed at the creation of thick deposits onto like-chemistry substrates for enabling repair of turbine engine hot-section components. SLE is a metal powder bed-based laser AM technology developed for nickel-base superalloys with equiaxed, directionally solidified, and single-crystal microstructural morphologies. Here, we combine process modeling, statistical design-of-experiments (DoE), and microstructural characterization to demonstrate fully metallurgically bonded, crack-free and dense deposits exceeding 1000 μm of SLE-processed IN100 powder onto IN100 cast substrates produced in a single pass. A combined thermal-fluid flow-solidification model of the SLE process compliments DoE-based process development. A customized quantitative metallography technique analyzes digital cross-sectional micrographs and extracts various microstructural parameters, enabling process model validation and process parameter optimization. Microindentation measurements show an increase in the hardness by 10 pct in the deposit region compared to the cast substrate due to microstructural refinement. The results illustrate one of the very few successes reported for the crack-free deposition of IN100, a notoriously "non-weldable" hot-section alloy, thus establishing the potential of SLE as an AM method suitable for hot-section component repair and for future new-make components in high gamma-prime containing crack-prone nickel-based superalloys.

Effect of boron and carbon addition on microstructure and mechanical properties of the aged gamma-prime strengthened alumina-forming austenitic alloys [Effect of boron and carbon addition on microstructure and mechanical properties of the aged gamma-prime alumina-forming austenitic alloys

DOE PAGES

Hu, Bin; Trotter, Geneva; Wang, Zhangwei; ...

2017-07-03

Here, the goal of this work was to understand the effects of aging at 800 °C on the microstructures and mechanical properties of two recently-developed AFA stainless steels based on Fe-14Cr-32Ni-3Nb-3Al-2Ti (wt.%), one of which contained small additions of boron and carbon. To that end both the size distributions and growth kinetics of the B2, Laves phase, L1 2 precipitates present were quantified. While the lattice parameter, morphology, size and coarsening behavior of the L1 2 precipitates was the same in both AFA alloys, the B and C enhanced the grain boundary coverage by both Laves phase and B2-NiAl precipitates,more » but suppressed their coarsening. These interstitial additions also suppressed the formation of twins and discontinuous precipitation, which were observed in the B and C-free material. It is shown that the yield strength at 700 °C is largely controlled by the size of the L1 2 precipitates, with the largest strengthening effect obtained after aging for 2.4 h for both AFA alloys. Longer aging time led to a loss of strength mainly due to the coarsening of the L1 2 precipitates.« less

Stress analysis, thermomechanical fatique evaluation, and root subcomponent testing of gamma/gamma prime-delta eutectic alloy

NASA Technical Reports Server (NTRS)

Sheffler, K. D.; Jackson, J. J.

1976-01-01

Thermomechanical fatigue (TMF) and root subcomponent tensile, creep, and low cycle fatigue (LCF) tests were conducted to determine the capability of a fully lamellar directionally solidified eutectic alloy to sustain the airfoil thermal fatigue and root attachment loads anticipated in advanced, hollow, high work turbine blades. A three dimensional finite element elastic stress analysis was performed on typical advanced hollow eutectic airfoil and root-platform designs to determine appropriate conditions for these tests. Results of TMF tests conducted on longitudinal specimens (stress axis parallel to the solidification direction) containing a simulated leading edge cooling hole pattern indicated the longitudinal TMF properties to be more than adequate for the particular advanced hollow blade analyzed, with the strain range for a 10,000 cycle life being more than 50% above the maximum strain range calculated for the advanced hollow blade.

The Advanced Gamma-ray Imaging System (AGIS): Telescope Optical System Designs

NASA Astrophysics Data System (ADS)

Hanna, David S.; Buckley, J. H.; Falcone, A.; Fegan, S.; Finley, J.; Guarino, V.; Kaaret, P.; Krawczynski, H.; Krennrich, F.; Konopelko, A.; Romani, R.; Vassilliev, V.; Optical System Working Group; AGIS Collaboration

2008-03-01

The concept of a future ground-based gamma-ray observatory, AGIS, in the energy range 20 GeV-200 TeV is based on an array of 50-200 imaging atmospheric Cherenkov telescopes (IACTs). The anticipated improvement of AGIS sensitivity, angular resolution, and reliability of operation imposes demanding technological and cost requirements on the design of IACTs. In this submission we will focus on the optical system (OS) of AGIS telescopes and consider options which include traditional Davies-Cotton and the other prime-focus telescope designs, as well as the novel two-mirror aplanatic OS originally proposed by Schwarzschild. The emerging new mirror production technologies based on replication processes, such as cold and hot glass slumping, cured CFRP, and electroforming, provide new opportunities for cost effective solutions for the design of the OS. We initially evaluate capabilities of these mirror fabrication methods for the AGIS project.

The improvement of cryogenic mechanical properties of Fe-12 Mn and Fe-8 Mn alloy steels through thermal/mechanical treatments

NASA Technical Reports Server (NTRS)

Hwang, S. K.; Morris, J. W., Jr.

1979-01-01

An investigation has been made to improve the low temperature mechanical properties of Fe-8Mn and Fe-12Mn-0.2 Ti alloy steels. A reversion annealing heat treatment in the two-phase (alpha + gamma) region following cold working has been identified as an effective treatment. In an Fe-12Mn-0.2Ti alloy a promising combination of low temperature (-196 C) fracture toughness and yield strength was obtained by this method. The improvement of properties was attributed to the refinement of grain size and to the introduction of a uniform distribution of retained austenite (gamma). It was also shown that an Fe-8Mn steel could be grain-refined by a purely thermal treatment because of its dislocated alpha-prime martensitic structure and absence of epsilon martensite. As a result, a significant reduction of ductile to brittle transition temperature was obtained.

Longitudinal shear behavior of several oxide dispersion strengthened alloys

NASA Technical Reports Server (NTRS)

Glasgow, T. K.

1978-01-01

Two commercial oxide dispersion strengthened (ODS) alloys, MA-753 and MA-754, and three experimental ODS alloys, MA-757E, MA-755E, and MA-6000E, were tested in shear at 760 C. Comparisons were made with other turbine blade and vane alloys. All of the ODS alloys exhibited less shear strength than directionally solidified Mar-M 200 = Hf or then conventionally cast B-1900. The strongest ODS alloy tested, MA-755E, was comparable in both shear and tensile strength to the lamellar directionally solidified eutectic alloy gamma/gamma prime - delta. Substantial improvements in shear resistance were found for all alloys tested when the geometry of the specimen was changed from one generating a transverse tensile stress in the shear area to one generating a transverse compressive stress. Finally, 760 C shear strength as a fraction of tensile strength was found to increase linearly with the log of the transverse tensile ductility.

Identification and characterization of Kaposi's sarcoma-associated herpesvirus open reading frame 11 promotor activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Lei

2008-01-01

Open reading frame 11 (ORF11) of Kaposi's sarcoma-associated herpesvirus belongs to a herpesviral homologous protein family shared by some members of the gamma- herpesvirus subfamily. Little is known about this ORF11 homologous protein family. We have characterized an unknown open reading frame, ORF11, located adjacent and in the opposite orientation to a well-characterized viral IL-6 gene. Northern blot analysis reveals that ORF11 is expressed during the KSHV lytic cycle with delayed-early transcription kinetics. We have determined the 5{prime} and 3{prime} untranslated region of the unspliced ORF11 transcript and identified both the transcription start site and the transcription termination site. Coremore » promoter region, representing ORF11 promoter activity, was mapped to a 159nt fragment 5{prime} most proximal to the transcription start site. A functional TATA box was identified in the core promoter region. Interestingly, we found that ORF11 transcriptional activation is not responsive to Rta, the KSHV lytic switch protein. We also discovered that part of the ORF11 promoter region, the 209nt fragment upstream of the transcription start site, was repressed by phorbol esters. Our data help to understand transcription regulation of ORF11 and to elucidate roles of ORF11 in KSHV pathogenesis and life cycle.« less

Intramuscular Priming and Intranasal Boosting Induce Strong Genital Immunity Through Secretory IgA in Minipigs Infected with Chlamydia trachomatis

PubMed Central

Lorenzen, Emma; Follmann, Frank; Bøje, Sarah; Erneholm, Karin; Olsen, Anja Weinreich; Agerholm, Jørgen Steen; Jungersen, Gregers; Andersen, Peter

2015-01-01

International efforts in developing a vaccine against Chlamydia trachomatis have highlighted the need for novel immunization strategies for the induction of genital immunity. In this study, we evaluated an intramuscular (IM) prime/intranasal boost vaccination strategy in a Göttingen Minipig model with a reproductive system very similar to humans. The vaccine was composed of C. trachomatis subunit antigens formulated in the Th1/Th17 promoting CAF01 adjuvant. IM priming immunizations with CAF01 induced a significant cell-mediated interferon gamma and interleukin 17A response and a significant systemic high-titered neutralizing IgG response. Following genital challenge, intranasally boosted groups mounted an accelerated, highly significant genital IgA response that correlated with enhanced bacterial clearance on day 3 post infection. By detecting antigen-specific secretory component (SC), we showed that the genital IgA was locally produced in the genital mucosa. The highly significant inverse correlation between the vaginal IgA SC response and the chlamydial load suggests that IgA in the minipig model is involved in protection against C. trachomatis. This is important both for our understanding of protective immunity and future vaccination strategies against C. trachomatis and genital pathogens in general. PMID:26734002

Neural correlates of cross-modal affective priming by music in Williams syndrome

PubMed Central

Lense, Miriam D.; Gordon, Reyna L.; Key, Alexandra P. F.; Dykens, Elisabeth M.

2014-01-01

Emotional connection is the main reason people engage with music, and the emotional features of music can influence processing in other domains. Williams syndrome (WS) is a neurodevelopmental genetic disorder where musicality and sociability are prominent aspects of the phenotype. This study examined oscillatory brain activity during a musical affective priming paradigm. Participants with WS and age-matched typically developing controls heard brief emotional musical excerpts or emotionally neutral sounds and then reported the emotional valence (happy/sad) of subsequently presented faces. Participants with WS demonstrated greater evoked fronto-central alpha activity to the happy vs sad musical excerpts. The size of these alpha effects correlated with parent-reported emotional reactivity to music. Although participant groups did not differ in accuracy of identifying facial emotions, reaction time data revealed a music priming effect only in persons with WS, who responded faster when the face matched the emotional valence of the preceding musical excerpt vs when the valence differed. Matching emotional valence was also associated with greater evoked gamma activity thought to reflect cross-modal integration. This effect was not present in controls. The results suggest a specific connection between music and socioemotional processing and have implications for clinical and educational approaches for WS. PMID:23386738

Precision cast vs. wrought superalloys

NASA Technical Reports Server (NTRS)

Tien, J. K.; Borofka, J. C.; Casey, M. E.

1986-01-01

While cast polycrystalline superalloys recommend themselves in virtue of better 'buy-to-fly' ratios and higher strengthening gamma-prime volume fractions than those of wrought superalloys, the expansion of their use into such critical superalloy applications as gas turbine hot section components has been slowed by insufficient casting process opportunities for microstructural control. Attention is presently drawn, however, to casting process developments facilitating the production of defect-tolerant superalloy castings having improved fracture reliability. Integrally bladed turbine wheel and thin-walled turbine exhaust case near-net-shape castings have been produced by these means.

Effects of Cobalt Concentration on the Relative Resistance to Octahedral and Cube Slip in Nickel-Base Superalloys

NASA Technical Reports Server (NTRS)

Bobeck, Gene E.; Miner, R. V.

1988-01-01

Compression yielding tests were performed at 760 C on crystals of the Ni base superalloys Rene 150 and a modified MAR-M247, both having two different Co concentrations. For both alloy bases, increasing Co concentration was shown to decrease the critical resolved shear stress for octahedral slip, but to have little effect on that for cube slip. The results suggest that decreasing complex stacking fault energy in the gamma-prime with increasing Co could account for the observed effects.

Determination of Gamma-Prime Site Occupancies in Nickel Superalloys Using Atom Probe Tomography and X-Ray Diffraction (Preprint)

DTIC Science & Technology

2012-08-01

unlimited that Ni and Al occupy different sites of the γ’ lattice and also in agreement with Equations ( 4 ) - ( 6 ). At E1 = 5989 eV, the structure factor...3. DATES COVERED (From - To) August 2012 Technical Paper 1 July 2012 – 1 August 2012 4 . TITLE AND SUBTITLE DETERMINATION OF γ’SITE OCCUPANCIES...PROGRAM ELEMENT NUMBER 62102F 6 . AUTHOR(S) J. Tiley, O. Senkov, and G. Viswanathan (AFRL/RXCM) S. Nag and R. Banerjee (University of North Texas

Analysis and Elimination of High Temperature Notch Induced Microcrack Initiation in Inconel 718 Nickel-Based Alloy

DTIC Science & Technology

1989-01-01

Compressor Rear Frame (ClF) which exhibits extensive cract:ing of the forward flange. ThL 1988 Actuarial Function data shows CRF crackiing As the number 2...Creep-Rupture properties of Waspaloy sheet to Sharp-Edged Notches in the Temperature Range of 1O000F-14O0OF. Journal of Basle Engineering, Trans ASME ...Dependence of the Notch Sensitivity of Waspaloy at 10000F-1400F on the Gamma Prime Phase, Journal of Basic Engineering, Trans ASME (in print at time of

Deformation characteristics and time-dependent notch sensitivity of Udimet 700 at intermediate temperatures

NASA Technical Reports Server (NTRS)

Wilson, D. J.

1975-01-01

Time-dependent notch sensitivity of Udimet 700 sheet, bar, and investment castings was observed between 1000 and 1400 F (538-760 C) but not at 1600 F (871 C). As was the case for Modified Waspaloy, Waspaloy, Rene 41, Inconel 718, and TD-NiCr, it occurred when notched specimens were loaded below the yield strength and when creep deformation was localized. For each gamma-prime strengthened alloy and notched specimen geometry, a stress-average particle size zone can be defined to characterize the notch-sensitive behavior.

Cost benefit study of advanced materials technology for aircraft turbine engines

NASA Technical Reports Server (NTRS)

Hillery, R. V.; Johnston, R. P.

1977-01-01

The cost/benefits of eight advanced materials technologies were evaluated for two aircraft missions. The overall study was based on a time frame of commercial engine use of the advanced material technologies by 1985. The material technologies evaluated were eutectic turbine blades, titanium aluminide components, ceramic vanes, shrouds and combustor liners, tungsten composite FeCrAly blades, gamma prime oxide dispersion strengthened (ODS) alloy blades, and no coat ODS alloy combustor liners. They were evaluated in two conventional takeoff and landing missions, one transcontinental and one intercontinental.

Partitioning of Nb, Mo, Ba, Ce, Pb, Th and U between immiscible carbonate and silicate liquids: Evaluating the effects of P2O5,F, and carbonate composition

NASA Technical Reports Server (NTRS)

Jones, J. H.; Walker, D.

1993-01-01

Previously we have reported carbonate liq./silicate liq. partition coefficients (D) for a standard suite of trace elements (Nb, Mo, Ba, Ce, Pb, Th, and U) and Ra and Pa as well. In brief, we have found that immiscible liquid partitioning is a strong function of temperature. As the critical temperature of the carbonate-silicate solvus is approached, all partition coefficients approach unity. Additionally, for the overwhelming majority of the partitioning elements, InD is a linear function of 'ionic field strength,' z/r, where z is the charge of the partitioned cation and r is its ionic radius.

Thermal and Mechanical Property Characterization of the Advanced Disk Alloy LSHR

NASA Technical Reports Server (NTRS)

Gabb, Timothy P.; Gayda, John; Telesman, Jack; Kantzos, Peter T.

2005-01-01

A low solvus, high refractory (LSHR) powder metallurgy disk alloy was recently designed using experimental screening and statistical modeling of composition and processing variables on sub-scale disks to have versatile processing-property capabilities for advanced disk applications. The objective of the present study was to produce a scaled-up disk and apply varied heat treat processes to enable full-scale demonstration of LSHR properties. Scaled-up disks were produced, heat treated, sectioned, and then machined into specimens for mechanical testing. Results indicate the LSHR alloy can be processed to produce fine and coarse grain microstructures with differing combinations of strength and time-dependent mechanical properties, for application at temperatures exceeding 1300 F.

Genomic organization, complete sequence, and chromosomal location of the gene for human eotaxin (SCYA11), an eosinophil-specific CC chemokine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcia-Zepeda, E.A.; Sarafi, M.N.; Luster, A.D.

1997-05-01

Eotaxin is a CC chemokine that is a specific chemoattractant for eosinophils and is implicated in the pathogenesis of eosinophilic inflammatory diseases, such as asthma. We describe the genomic organization, complete sequence, including 1354 bp 5{prime} of the RNA initiation site, and chromosomal localization of the human eotaxin gene. Fluorescence in situ hybridization analysis localized eotaxin to human chromosome 17, in the region q21.1-q21.2, and the human gene name SCYA11 was assigned. We also present the 5{prime} flanking sequence of the mouse eotaxin gene and have identified several regulatory elements that are conserved between the murine and the human promoters.more » In particular, the presence of elements such as NF-{Kappa}B, interferon-{gamma} response element, and glucocorticoid response element may explain the observed regulation of the eotaxin gene by cytokines and glucocorticoids. 17 refs., 4 figs., 1 tab.« less

Host cell reactivation of gamma-irradiated adenovirus 5 in human cell lines of varying radiosensitivity.

PubMed Central

Eady, J. J.; Peacock, J. H.; McMillan, T. J.

1992-01-01

DNA repair processes play an important role in the determination of radiation response in both normal and tumour cells. We have investigated one aspect of DNA repair in a number of human cell lines of varying radiosensitivity using the adenovirus 5 host cell reactivation assay (HCR). In this technique, gamma-irradiated virions are used to infect cells and the ability of the cellular repair systems to process this damage is assayed by a convenient immunoperoxidase method recognising viral structural antigen expression on the cell membrane 48 h after infection. Reduced HCR was exhibited by radioresistant HeLa cells and by a radiosensitive neuroblastoma cell line, HX142. In contrast, an ataxia telangiectasia cell line, AT5 BIVA, did not show reduced HCR. On the basis of these results we can make no general conclusions about the relevance of HCR to cellular radiosensitivity. We have extended these studies to determine whether our cell lines exhibited enhanced viral reactivation (ER) following a small priming dose of gamma-radiation given to the cells before viral infection. No evidence for this phenomenon was found either in normal or tumour cell lines. PMID:1637659

Measurements of Amplified Magnetic Field and Cosmic-Ray Content in Supernova Remnants

NASA Astrophysics Data System (ADS)

Uchiyama, Yasunobu

Supernova explosions drive collisionless shocks in the interstellar (or circumstellar) medium. Such shocks are mediated by plasma waves, resulting in the shock transition on a scale much smaller than the collisional mean free path. Galactic cosmic rays are widely considered to be accelerated at collisionless shocks in supernova remnants via diffusive shock acceleration. New high-energy data coming from the X-ray and gamma-ray satellites and from imaging air Cerenkov telescopes are making possible to study physics of particle acceleration at supernova shocks, such as magnetic field amplification which is considered to be realized as part of shock acceleration process and the energy content of cosmic-ray particles in the supernova shell. In particular, GeV observations with the Fermi Gamma-ray Space Telescope offer the prime means to establish the origin of the gamma-rays, and to measure the cosmic-ray content. Moreover they provide a new opportunity to learn about how particle acceleration responds to environ-mental effects. I will present recent observational results from the Chandra and Suzaku X-ray satellites and new results from the LAT onboard Fermi, and discuss their implications to the origin of galactic cosmic rays.

Durability Assessment of TiAl Alloys

NASA Technical Reports Server (NTRS)

Draper, Susan L.; Lerch, Bradley A.

2008-01-01

The durability of TiAl is a prime concern for the implementation of TiAl into aerospace engines. Two durability issues, the effect of high temperature exposure on mechanical properties and impact resistance, have been investigated and the results are summarized in this paper. Exposure to elevated temperatures has been shown to be detrimental to the room temperature ductility of gamma alloys with the most likely mechanisms being the ingress of interstitials from the surface. Fluorine ion implantation has been shown to improve the oxidation resistance of gamma alloys, and ideally it could also improve the environmental embrittlement of high Nb content TiAl alloys. The effect of F ion implantation on the surface oxidation and embrittlement of a third generation, high Nb content TiAl alloy (Ti-45Al-5Nb-B-C) were investigated. Additionally, the ballistic impact resistance of a variety of gamma alloys, including Ti-48Al-2Cr- 2Nb, Ti-47Al-2Cr-2Nb, ABB-2, ABB-23, NCG359E, 95A and Ti-45Al-5Nb-B-C was accessed. Differences in the ballistic impact properties of the various alloys will be discussed, particularly with respect to their manufacturing process, microstructure, and tensile properties.

Gamma prime precipitation modeling and strength responses in powder metallurgy superalloys

NASA Astrophysics Data System (ADS)

Mao, Jian

Precipitation-hardened nickel-based superalloys have been widely used as high temperature structural materials in gas turbine engine applications for more than 50 years. Powder metallurgy (P/M) technology was introduced as an innovative manufacturing process to overcome severe segregation and poor workability of alloys with high alloying contents. The excellent mechanical properties of P/M superalloys also depend upon the characteristic microstructures, including grain size and size distribution of gamma' precipitates. Heat treatment is the most critical processing step that has ultimate influences on the microstructure, and hence, on the mechanical properties of the materials. The main objective of this research was to study the gamma ' precipitation kinetics in various cooling circumstances and also study the strength response to the cooling history in two model alloys, Rne88DT and U720LI. The research is summarized below: (1) An experimental method was developed to allow accurate simulation and control of any desired cooling profile. Two novel cooling methods were introduced: continuous cooling and interrupt cooling. Isothermal aging was also carried out. (2) The growth and coarsening kinetics of the cooling gamma' precipitates were experimentally studied under different cooling and aging conditions, and the empirical equations were established. It was found that the cooling gamma' precipitate versus the cooling rate follows a power law. The gamma' precipitate size versus aging time obeys the LSW cube law for coarsening. (3) The strengthening of the material responses to the cooling rate and the decreasing temperature during cooling was investigated in both alloys. The tensile strength increases with the cooling rate. In addition, the non-monotonic response of strength versus interrupt temperature is of great interest. (4) An energy-driven model integrated with the classic growth and coarsen theories was successfully embedded in a computer program developed to simulate the cooling gamma ' precipitation based on the first principle of thermodynamics. The combination of the thermodynamic and the kinetic approaches provided a more practical method to determine the critical nucleation energy. (5) The simulation results proved the gamma' burst theory and the existence of the multi-stage burst of gamma' precipitates, which shows good agreement with the experimental data in a variety of aspects.

Precipitation of aluminum nitride in a high strength maraging steel with low nitrogen content

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeanmaire, G., E-mail: guillaume.jeanmaire@univ-lorraine.fr; Aubert and Duval, BP1, 63770 Les Ancizes; Dehmas, M.

2014-12-15

In the present work, aluminum nitride (AlN) precipitation was investigated in a X23NiCoCrMoAl13-6-3 maraging steel with low nitrogen content (wt.% N = 5.5 ppm). A reliable and robust automatic method by scanning electron microscopy observations coupled with energy dispersive X-ray spectroscopy was developed for the quantification of AlN precipitates. The first stage was to identify the solvus temperature and to develop a heat treatment able to dissolve the AlN precipitates. The experimental determination of equilibrium conditions and solvus temperature show good agreement with ThermoCalc® simulation. Then, from this AlN-free state, the cooling rate, isothermal holding time and temperature were themore » subject of an intensive investigation in the austenite region of this maraging steel. In spite of the high temperatures used during heat treatments, the growth kinetic of the largest AlN precipitates (> 1 μm) is slow. The cooling rate has a major effect on the size and the number density of AlN due to a higher driving force for nucleation at low temperatures. At last, quenching prior to isothermal annealing at high temperatures leads to fine and dense AlN precipitation, resulting from the martensite to austenite transformation. Experimental results will be discussed and compared with kinetic data obtained with the mobility database MobFe2 implemented in Dictra® software. - Highlights: • Slow dissolution kinetic of AlN precipitates due to both their large size and small chemical driving force • Significant effects of cooling rate prior isothermal heat treatment, holding time and temperature on AlN precipitation • Size of AlN precipitates can be reduced by quenching prior isothermal holding. • Fine precipitation of AlN related to the α → γ transformation.« less

History Dependence of the Microstructure on Time-Dependent Deformation During In-Situ Cooling of a Nickel-Based Single-Crystal Superalloy

NASA Astrophysics Data System (ADS)

Panwisawas, Chinnapat; D'Souza, Neil; Collins, David M.; Bhowmik, Ayan; Roebuck, Bryan

2018-05-01

Time-dependent plastic deformation through stress relaxation and creep deformation during in-situ cooling of the as-cast single-crystal superalloy CMSX-4® has been studied via neutron diffraction, transmission electron microscopy, electro-thermal miniature testing, and analytical modeling across two temperature regimes. Between 1000 °C and 900 °C, stress relaxation prevails and gives rise to softening as evidenced by a decreased dislocation density and the presence of long segment stacking faults in γ phase. Lattice strains decrease in both the γ matrix and γ' precipitate phases. A constitutive viscoplastic law derived from in-situ isothermal relaxation test under-estimates the equivalent plastic strain in the prediction of the stress and strain evolution during cooling in this case. It is thereby shown that the history dependence of the microstructure needs to be taken into account while deriving a constitutive law and which becomes even more relevant at high temperatures approaching the solvus. Higher temperature cooling experiments have also been carried out between 1300 °C and 1150 °C to measure the evolution of stress and plastic strain close to the γ' solvus temperature. In-situ cooling of samples using ETMT shows that creep dominates during high-temperature deformation between 1300 °C and 1220 °C, but below a threshold temperature, typically 1220 °C work hardening begins to prevail from increasing γ' fraction and resulting in a rapid increase in stress. The history dependence of prior accumulated deformation is also confirmed in the flow stress measurements using a single sample while cooling. The saturation stresses in the flow stress experiments show very good agreement with the stresses measured in the cooling experiments when viscoplastic deformation is dominant. This study demonstrates that experimentation during high-temperature deformation as well as the history dependence of the microstructure during cooling plays a key role in deriving an accurate viscoplastic constitutive law for the thermo-mechanical process during cooling from solidification.

Humoral and Cell-Mediated Immune Responses to Alternate Booster Schedules of Anthrax Vaccine Adsorbed in Humans

PubMed Central

Sabourin, Carol L.; Schiffer, Jarad M.; Niemuth, Nancy A.; Semenova, Vera A.; Li, Han; Rudge, Thomas L.; Brys, April M.; Mittler, Robert S.; Ibegbu, Chris C.; Wrammert, Jens; Ahmed, Rafi; Parker, Scott D.; Babcock, Janiine; Keitel, Wendy; Poland, Gregory A.; Keyserling, Harry L.; El Sahly, Hana; Jacobson, Robert M.; Marano, Nina; Plikaytis, Brian D.; Wright, Jennifer G.

2016-01-01

Protective antigen (PA)-specific antibody and cell-mediated immune (CMI) responses to annual and alternate booster schedules of anthrax vaccine adsorbed (AVA; BioThrax) were characterized in humans over 43 months. Study participants received 1 of 6 vaccination schedules: a 3-dose intramuscular (IM) priming series (0, 1, and 6 months) with a single booster at 42 months (4-IM); 3-dose IM priming with boosters at 18 and 42 months (5-IM); 3-dose IM priming with boosters at 12, 18, 30, and 42 months (7-IM); the 1970 licensed priming series of 6 doses (0, 0.5, 1, 6, 12, and 18 months) and two annual boosters (30 and 42 months) administered either subcutaneously (SQ) (8-SQ) or IM (8-IM); or saline placebo control at all eight time points. Antibody response profiles included serum anti-PA IgG levels, subclass distributions, avidity, and lethal toxin neutralization activity (TNA). CMI profiles included frequencies of gamma interferon (IFN-γ)- and interleukin 4 (IL-4)-secreting cells and memory B cells (MBCs), lymphocyte stimulation indices (SI), and induction of IFN-γ, IL-2, IL-4, IL-6, IL-1β, and tumor necrosis factor alpha (TNF-α) mRNA. All active schedules elicited high-avidity PA-specific IgG, TNA, MBCs, and T cell responses with a mixed Th1-Th2 profile and Th2 dominance. Anti-PA IgG and TNA were highly correlated (e.g., month 7, r2 = 0.86, P < 0.0001, log10 transformed) and declined in the absence of boosters. Boosters administered IM generated the highest antibody responses. Increasing time intervals between boosters generated antibody responses that were faster than and superior to those obtained with the final month 42 vaccination. CMI responses to the 3-dose IM priming remained elevated up to 43 months. (This study has been registered at ClinicalTrials.gov under registration no. NCT00119067.) PMID:26865594

The behaviour of boron in a peraluminous granite-pegmatite system and associated hydrothermal solutions: a melt and fluid-inclusion study

NASA Astrophysics Data System (ADS)

Thomas, Rainer; Förster, Hans-Jürgen; Heinrich, Wilhelm

2002-09-01

Detailed analyses of melt and fluid inclusions combined with an electron-microprobe survey of boron-bearing minerals reveal the evolution of boron in a highly evolved peraluminous granite-pegmatite complex and the associated high- and medium-temperature ore-forming hydrothermal fluids (Ehrenfriedersdorf, Erzgebirge, Germany). Melt inclusions in granite represent embryonic pegmatite-forming melts containing about 10 wt% H2O and 1.8 wt% B2O3. These melts are also enriched in F, P, and other incompatible elements such as Be, Sn, Rb, and Cs. Ongoing differentiation and volatile enrichment drove the system into a solvus, where two pegmatite-forming melts coexisted. The critical point is at about 712 °C, 100 MPa, 20 wt% H2O and 4.1 wt% B2O3. Cooling and concomitant fractional crystallisation from 700 to 500 °C induced development of two conjugate melts, an H2O-poor (A-melt) and an H2O-rich melt (B-melt) along the opening solvus. Boron is a major element in both melts and is preferentially partitioned into the H2O-rich melt. Temperature-dependent distribution coefficients $ D{boron}{{B - melt/A - melt}} $ are 1.3 at 650 °C, 1.5 at 600 °C, and 1.8 at 500 °C. In both melts, boron concentrations decreased during cooling because of exsolution of a boron-rich hypersaline brine throughout the pegmatitic stage. Boromuscovite containing up to 8.5 wt% was another sink for boron at this stage. The end of the melt-dominated pegmatitic stage was attained at a solidus temperature of around 490 °C. Fluid inclusions of the hydrothermal stage reveal trapping temperatures of 480 to 370 °C, along with varying densities and highly variable B2O3 contents ranging from 0.20 to 2.94 wt%. A boiling system evolved, indicating a complex interplay between closed- and open-system behaviour. Pressure switched from lithostatic to hydrostatic and back, generating hydrothermal convection cells where meteoric waters were introduced and mixed with magmatic fluids. Boron-rich solutions originated from magmatic fluids, whereas boron-depleted fluids were mainly of meteoric origin. This highlights the potential of boron for discriminating fluids of different origin. Tin is continuously enriched during the evolution because tin and boron are cross-linked by formation of boron-, fluorine- and tin-fluorine-bearing complexes and is finally deposited within quartz-cassiterite veins during the transition from closed- to open-system behaviour. Boron does not only trace the complex evolution of the Ehrenfriedersdorf complex but exerts, together with H2O, F and P, an important control on the physical and chemical properties of pegmatite-forming melts, and particularly on the formation of a two-melt solvus at low pressure. We discuss this with respect to experimental results on H2O solubility and the critical behaviour of the haplogranite-water system which contained variable concentrations of volatiles.

The behaviour of boron in a peraluminous granite-pegmatite system and associated hydrothermal solutions: a melt and fluid-inclusion study

NASA Astrophysics Data System (ADS)

Thomas, Rainer; Förster, Hans-Jürgen; Heinrich, Wilhelm

Detailed analyses of melt and fluid inclusions combined with an electron-microprobe survey of boron-bearing minerals reveal the evolution of boron in a highly evolved peraluminous granite-pegmatite complex and the associated high- and medium-temperature ore-forming hydrothermal fluids (Ehrenfriedersdorf, Erzgebirge, Germany). Melt inclusions in granite represent embryonic pegmatite-forming melts containing about 10 wt% H2O and 1.8 wt% B2O3. These melts are also enriched in F, P, and other incompatible elements such as Be, Sn, Rb, and Cs. Ongoing differentiation and volatile enrichment drove the system into a solvus, where two pegmatite-forming melts coexisted. The critical point is at about 712 °C, 100 MPa, 20 wt% H2O and 4.1 wt% B2O3. Cooling and concomitant fractional crystallisation from 700 to 500 °C induced development of two conjugate melts, an H2O-poor (A-melt) and an H2O-rich melt (B-melt) along the opening solvus. Boron is a major element in both melts and is preferentially partitioned into the H2O-rich melt. Temperature-dependent distribution coefficients $ D{boron}{{B - melt/A - melt}} $ are 1.3 at 650 °C, 1.5 at 600 °C, and 1.8 at 500 °C. In both melts, boron concentrations decreased during cooling because of exsolution of a boron-rich hypersaline brine throughout the pegmatitic stage. Boromuscovite containing up to 8.5 wt% was another sink for boron at this stage. The end of the melt-dominated pegmatitic stage was attained at a solidus temperature of around 490 °C. Fluid inclusions of the hydrothermal stage reveal trapping temperatures of 480 to 370 °C, along with varying densities and highly variable B2O3 contents ranging from 0.20 to 2.94 wt%. A boiling system evolved, indicating a complex interplay between closed- and open-system behaviour. Pressure switched from lithostatic to hydrostatic and back, generating hydrothermal convection cells where meteoric waters were introduced and mixed with magmatic fluids. Boron-rich solutions originated from magmatic fluids, whereas boron-depleted fluids were mainly of meteoric origin. This highlights the potential of boron for discriminating fluids of different origin. Tin is continuously enriched during the evolution because tin and boron are cross-linked by formation of boron-, fluorine- and tin-fluorine-bearing complexes and is finally deposited within quartz-cassiterite veins during the transition from closed- to open-system behaviour. Boron does not only trace the complex evolution of the Ehrenfriedersdorf complex but exerts, together with H2O, F and P, an important control on the physical and chemical properties of pegmatite-forming melts, and particularly on the formation of a two-melt solvus at low pressure. We discuss this with respect to experimental results on H2O solubility and the critical behaviour of the haplogranite-water system which contained variable concentrations of volatiles.

Recombinant bovine S100A8 and A9 enhance IL-1β secretion of interferon-gamma primed monocytes.

PubMed

Koy, Mirja; Hambruch, Nina; Hussen, Jamal; Pfarrer, Christiane; Seyfert, Hans-Martin; Schuberth, Hans-Joachim

2013-09-15

Calgranulin A (S100A8) and B (S100A9) are found at high levels in inflamed tissue and have been associated with acute and chronic inflammatory disorders. Calgranulins are discussed as damage-associated molecular patterns (DAMPs). To analyze the role of calgranulins for inflammatory responses, bovine S100A8 and S100A9 were cloned, successfully expressed and FPLC-purified. Both molecules did not induce NF-κB activation in boTLR4-transfected HEK293 cells and stimulation of bovine monocytes with both proteins did not result in interleukin 1β (IL-1β) secretion or an upregulated mRNA expression of selected genes (IL1B, TNF, CXCL8, IL10, IL12). However, Interferon γ (IFN-γ) primed bovine monocytes released significantly higher amounts of IL-1β after stimulation with S100A8, S100A9, and co-stimulation with adenosine triphosphate (ATP). In IL-4/IL-13-primed monocytes, the IL-1β release was completely abrogated. The results imply that TLR4/MyD88/NF-κB-independent S100A8/A9-mediated activation of the inflammasome in cattle is favored in a Th1 environment and that S100A8 and S100A9 act as a DAMP in cattle. Copyright © 2013 Elsevier B.V. All rights reserved.

Plasmacytoid dendritic cells induce NK cell-dependent, tumor antigen-specific T cell cross-priming and tumor regression in mice.

PubMed

Liu, Chengwen; Lou, Yanyan; Lizée, Gregory; Qin, Hong; Liu, Shujuan; Rabinovich, Brian; Kim, Grace J; Wang, Yi-Hong; Ye, Yang; Sikora, Andrew G; Overwijk, Willem W; Liu, Yong-Jun; Wang, Gang; Hwu, Patrick

2008-03-01

A prerequisite for strong adaptive antiviral immunity is the robust initial activation of the innate immune system, which is frequently mediated by TLR-activated plasmacytoid DCs (pDCs). Natural antitumor immunity is often comparatively weak, potentially due to the lack of TLR-mediated activation signals within the tumor microenvironment. To assess whether pDCs are capable of directly facilitating effective antitumor immune responses, mice bearing established subcutaneous B16 melanoma tumors were administered TLR9-activated pDCs directly into the tumor. We found that TLR9-activated pDCs induced robust, spontaneous CTL cross-priming against multiple B16 tumor antigens, leading to the regression of both treated tumors and untreated tumors at distant contralateral sites. This T cell cross-priming was mediated by conventional DCs (cDCs) and was completely dependent upon the early recruitment and activation of NK cells at the tumor site. NK cell recruitment was mediated by CCR5 via chemokines secreted by pDCs, and optimal IFN-gamma production by NK cells was mediated by OX40L expressed by pDCs. Our data thus demonstrated that activated pDCs are capable of initiating effective and systemic antitumor immunity through the orchestration of an immune cascade involving the sequential activation of NK cells, cDCs, and CD8(+) T cells.

Prime-boost BCG vaccination with DNA vaccines based in β-defensin-2 and mycobacterial antigens ESAT6 or Ag85B improve protection in a tuberculosis experimental model

PubMed Central

Cervantes-Villagrana, Alberto R.; Hernández-Pando, Rogelio; Biragyn, Arya; Castañeda-Delgado, Julio; Bodogai, Monica; Martínez-Fierro, Margarita; Sada, Eduardo; Trujillo, Valentin; Enciso-Moreno, Antonio; Rivas-Santiago, Bruno

2018-01-01

The World Health Organization (WHO) has estimated that there are about 8 million new cases annually of active Tuberculosis (TB). Despite its irregular effectiveness (0–89%), the Bacillus Calmette-Guérin) BCG is the only vaccine available worldwide for prevention of TB; thus, the design is important of novel and more efficient vaccination strategies. Considering that β-defensin-2 is an antimicrobial peptide that induces dendritic cell maturation through the TLR-4 receptor and that both ESAT-6 and Ag85B are immunodominant mycobacterial antigens and efficient activators of the protective immune response, we constructed two DNA vaccines by the fusion of the gene encoding β-defensin-2 and antigens ESAT6 (pDE) and 85B (pDA). After confirming efficient local antigen expression that induced high and stable Interferon gamma (IFN-γ) production in intramuscular (i.m.) vaccinated Balb/c mice, groups of mice were vaccinated with DNA vaccines in a prime-boost regimen with BCG and with BCG alone, and 2 months later were challenged with the mild virulence reference strain H37Rv and the highly virulent clinical isolate LAM 5186. The level of protection was evaluated by survival, lung bacilli burdens, and extension of tissue damage (pneumonia). Vaccination with both DNA vaccines showed similar protection to that of BCG. After the challenge with the highly virulent Mycobacterium tuberculosis strain, animals that were prime-boosted with BCG and then boosted with both DNA vaccines showed significant higher survival and less tissue damage than mice vaccinated only with BCG. These results suggest that improvement of BCG vaccination, such as the prime-boost DNA vaccine, represents a more efficient vaccination scheme against TB. PMID:23196205

Safety and immunogenicity of mammalian cell derived and Modified Vaccinia Ankara vectored African swine fever subunit antigens in swine.

PubMed

Lopera-Madrid, Jaime; Osorio, Jorge E; He, Yongqun; Xiang, Zuoshuang; Adams, L Garry; Laughlin, Richard C; Mwangi, Waithaka; Subramanya, Sandesh; Neilan, John; Brake, David; Burrage, Thomas G; Brown, William Clay; Clavijo, Alfonso; Bounpheng, Mangkey A

2017-03-01

A reverse vaccinology system, Vaxign, was used to identify and select a subset of five African Swine Fever (ASF) antigens that were successfully purified from human embryonic kidney 293 (HEK) cells and produced in Modified vaccinia virus Ankara (MVA) viral vectors. Three HEK-purified antigens [B646L (p72), E183L (p54), and O61R (p12)], and three MVA-vectored antigens [B646L, EP153R, and EP402R (CD2v)] were evaluated using a prime-boost immunization regimen swine safety and immunogenicity study. Antibody responses were detected in pigs following prime-boost immunization four weeks apart with the HEK-293-purified p72, p54, and p12 antigens. Notably, sera from the vaccinees were positive by immunofluorescence on ASFV (Georgia 2007/1)-infected primary macrophages. Although MVA-vectored p72, CD2v, and EP153R failed to induce antibody responses, interferon-gamma (IFN-γ + ) spot forming cell responses against all three antigens were detected one week post-boost. The highest IFN-γ + spot forming cell responses were detected against p72 in pigs primed with MVA-p72 and boosted with the recombinant p72. Antigen-specific (p12, p72, CD2v, and EP153R) T-cell proliferative responses were also detected post-boost. Collectively, these results are the first demonstration that ASFV subunit antigens purified from mammalian cells or expressed in MVA vectors are safe and can induce ASFV-specific antibody and T-cell responses following a prime-boost immunization regimen in swine. Copyright © 2017 Elsevier B.V. All rights reserved.

CCL3 Enhances Antitumor Immune Priming in the Lymph Node via IFNγ with Dependency on Natural Killer Cells

PubMed Central

Allen, Frederick; Rauhe, Peter; Askew, David; Tong, Alexander A.; Nthale, Joseph; Eid, Saada; Myers, Jay T.; Tong, Caryn; Huang, Alex Y.

2017-01-01

Lymph node (LN) plays a critical role in tumor cell survival outside of the primary tumor sites and dictates overall clinical response in many tumor types (1, 2). Previously, we and others have demonstrated that CCL3 plays an essential role in orchestrating T cell—antigen-presenting cell (APC) encounters in the draining LN following vaccination, and such interactions enhance the magnitude of the memory T cell pool (3–5). In the current study, we investigate the cellular responses in the tumor-draining lymph nodes (TDLNs) of a CCL3-secreting CT26 colon tumor (L3TU) as compared to wild-type tumor (WTTU) during the priming phase of an antitumor response (≤10 days). In comparison to WTTU, inoculation of L3TU resulted in suppressed tumor growth, a phenomenon that is accompanied by altered in vivo inflammatory responses on several fronts. Autologous tumor-derived CCL3 (aCCL3) secretion by L3TU bolstered the recruitment of T- and B-lymphocytes, tissue-migratory CD103+ dendritic cells (DCs), and CD49b+ natural killer (NK) cells, resulting in significant increases in the differentiation and activation of multiple Interferon-gamma (IFNγ)-producing leukocytes in the TDLN. During this early phase of immune priming, NK cells constitute the major producers of IFNγ in the TDLN. CCL3 also enhances CD8+ T cell proliferation and differentiation by augmenting DC capacity to drive T cell activation in the TDLN. Our results revealed that CCL3-dependent IFNγ production and CCL3-induced DC maturation drive the priming of effective antitumor immunity in the TDLN. PMID:29109732

Development of a High Temperature Sensor Based on Transformation-Induced Resistivity

DTIC Science & Technology

2010-02-01

qu ilib riu m T , C Ni-15.75Al Figure 2. Kinetics of γ´ Precipitation During Continuous Cooling of Ni-Al Alloys as a Function of Cooling Rate [7...2.5 at.%) γ’ solvus, T °C HT1 Time @ 1220°C HT2 Time @ 1220°C wt.% at.% wt.% at.% wt.% wt.% Hrs Hrs A1 89.58 83.5 5.67 11.5 4.75...mm] 9.69 9.58 9.49 9.75 9.49 10.30 10.39 10.56 Thickness, t [mm] 2.53 2.55 2.63 2.57 2.34 3.18 3.05 2.38 Aspect ratio, c 1.04 1.03 1.16 1.03 1.04

Gamma Prime Morphology and Creep Properties of Nickel Based Superalloys With Platinum Group Metal Additions (Preprint)

DTIC Science & Technology

2008-04-01

scann bakelite, and s opolish. Samp (C2H4O2), 33% hydrofluoric a o analyze micr onditions. Al age of 20 kV. PGM alloys. and post-creep n the two...spacing Table 1 alloys i only Ir temper amount Alloys from 1 wt%, th window solidus elemen the fig experim arrows indicate from al decreas compos...decreas the poin [2 [1 [3 D1 Figure I alloy wt%) compo the gra oils were prepa to the applie ss using grit olishing at a t used for al ), 10

Plasma membrane associated phospholipase C from human platelets: Synergistic stimulation of phosphatidylinositol 4,5-bisphosphate hydrolysis by thrombin and guanosine 5 prime -O-(3-thiotriphosphate)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baldassare, J.J.; Henderson, P.A.; Fisher, G.J.

1989-01-10

The effects of thrombin and GTP{gamma}S on the hydrolysis of phosphoinositides by membrane-associated phospholipase C (PLC) from human platelets were examined with endogenous ({sup 3}H)inositol-labeled membranes or with lipid vesicles containing either ({sup 3}H)phosphatidylinositol or ({sup 3}H)phosphatidylinositol 4,5-bisphosphate. GTP{gamma}S (1 {mu}M) or thrombin (1 unit/mL) did not stimulate release of inositol trisphosphate (IP{sub 3}), inositol bisphosphate (IP{sub 2}), or inositol phosphate (IP) from ({sup 3}H)inositol-labeled membranes. IP{sub 2} and IP{sub 3}, but not IP, from ({sup 3}H)inositol-labeled membranes were, however, stimulated 3-fold by GTP{gamma}S (1 {mu}M) plus thrombin (1 unit/mL). A higher concentration of GTP{gamma}S (100 {mu}M) alone also stimulatedmore » IP{sub 2} and IP{sub 3}, but not IP, release. In the presence of 1 mM calcium, release of IP{sub 2} and IP{sub 3} was increased 6-fold over basal levels; however, formation of IP was not observed. At submicromolar calcium concentration, hydrolysis of exogenous phosphatidylinositol 4,5-bisphosphate (PIP{sub 2}) by platelet membrane associated PLC was also markedly enhanced by GTP{gamma}S (100 {mu}M) or GTP{gamma}S (1 {mu}M) plus thrombin (1 unit/mL). Under identical conditions, exogenous phosphatidylinositol (PI) was not hydrolyzed. The same substrate specificity was observed when the membrane-associated PLC was activated with 1 mM calcium. Thrombin-induced hydrolysis of PIP{sub 2} was inhibited by treatment of the membranes with pertussis toxin or pretreatment of intact platelets with 12-O-tetradecanoyl-13-acetate (TPA) prior to preparation of membranes. Pertussis toxin did not inhibit GTP{gamma}S (100 {mu}M) or calcium (1 mM) dependent PIP{sub 2} breakdown, while TPA inhibited GTP{gamma}S-dependent but not calcium-dependent phospholipase C activity.« less

TERMINATION OF TOLERANCE TO HUMAN GAMMA GLOBULIN IN MICE BY ANTIGEN AND BACTERIAL LIPOPOLYSACCHARIDE (ENDOTOXIN)

PubMed Central

Chiller, Jacques M.; Weigle, William O.

1973-01-01

Bacterial lipopolysaccharides (endotoxin) allowed the circumvention of the thymus-derived (T) cell helper function otherwise required for the antibody response in mice to human gamma globulin (HGG). In an analogous fashion, the state of tolerance to HGG, existing at a time when bone marrow-derived (B) cells had lost their unresponsiveness, could be terminated by the injection of both immunogenic HGG and endotoxin, but by neither given alone. However, no effect on tolerance to HGG could be observed when this regimen was followed at a time when B cells were tolerant. After the spontaneous recovery from tolerance in B cells, it seemed that specific priming was occurring in that population. This phenomenon was observed either by the injection of endotoxin and HGG or by the adoptive transfer of cells into irradiated hosts. These data have been discussed in the light of potential autoimmune manifestations that could theoretically follow a simultaneous gram-negative bacterial infection along with a release of self-antigen. PMID:4120288

Guanine nucleotide-binding protein regulation of melatonin receptors in lizard brain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rivkees, S.A.; Carlson, L.L.; Reppert, S.M.

Melatonin receptors were identified and characterized in crude membrane preparations from lizard brain by using {sup 125}I-labeled melatonin ({sup 125}I-Mel), a potent melatonin agonist. {sup 125}I-Mel binding sites were saturable; Scatchard analysis revealed high-affinity and lower affinity binding sites, with apparent K{sub d} of 2.3 {plus minus} 1.0 {times} 10{sup {minus}11} M and 2.06 {plus minus} 0.43 {times} 10{sup {minus}10} M, respectively. Binding was reversible and inhibited by melatonin and closely related analogs but not by serotonin or norepinephrine. Treatment of crude membranes with the nonhydrolyzable GTP analog guanosine 5{prime}-({gamma}-thio)triphosphate (GTP({gamma}S)), significantly reduced the number of high-affinity receptors and increasedmore » the dissociation rate of {sup 125}I-Mel from its receptor. Furthermore, GTP({gamma}S) treatment of ligand-receptor complexes solubilized by Triton X-100 also led to a rapid dissociation of {sup 125}I-Mel from solubilized ligand-receptor complexes. Gel filtration chromatography of solubilized ligand-receptor complexes revealed two major peaks of radioactivity corresponding to M{sub r} > 400,000 and M{sub r} ca. 110,000. This elution profile was markedly altered by pretreatment with GTP({gamma}S) before solubilization; only the M{sub r} 110,000 peak was present in GTP({gamma}S)-pretreated membranes. The results strongly suggest that {sup 125}I-mel binding sites in lizard brain are melatonin receptors, with agonist-promoted guanine nucleotide-binding protein (G protein) coupling and that the apparent molecular size of receptors uncoupled from G proteins is about 110,000.« less

Oxidative Stress and Skeletal Health with Low-Dose, Low-LET (Linear Energy Transfer) Ionizing Radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Globus, Ruth K.

We performed in vivo and in vitro experiments to accomplish the following specific aims of this project: 1) determine if low dose, low LET radiation affects skeletal remodeling at structural, cellular and molecular levels and 2) determine if low dose, low LET radiation modulates skeletal health during aging via oxidative mechanisms. A third aim is supported by NASA supplement to this DOE grant focusing on the influence of high LET radiation on bone. A series of experiments were conducted at the NASA Space Radiation Laboratory at Brookhaven, NSRL-BNL, using iron (56Fe) or a sequential exposure to protons / iron /more » protons, and separate experiments at NASA Ames Research Center (ARC) using 137Cs. The following provides a summary of key findings. (1) Exposure of nine-week old female mice to priming doses of gamma radiation (10cGy x 5) did not significantly affect bone volume/total volume (BV/TV) or microarchitecture as analyzed by 3D microcomputed tomography. As expected, exposure to the challenge dose of 2 Gy gamma irradiation resulted in significant decreases in BV/TV. The priming dose combined with the 2Gy challenge dose had no further effect on BV/TV compared to challenge dose alone, with the sole exception of the Structural Model Index (SMI). SMI reflects the ratio of rods-to-plates in cancellous bone tissue, such that higher SMI values indicate a tendency toward a weaker structure compared to lower SMI values. Mice treated with both priming and challenge dose had 25% higher SMI values compared to sham-irradiated controls and 7% higher values compared to mice treated with the challenge dose alone. Thus, although this priming regimen had relatively modest effects on cancellous tissue, the difference in SMI suggests this fractionated priming doses have adverse, rather than beneficial, effects on bone structure. (2) In 10-week old male mice, a single exposure to 100cGy of 137Cs reduces trabecular bone number and connectivity density by 20% and 36% respectively one month after irradiation (IR). At four months post-IR, these animals were comparable to sham-treated controls with regards to the abovementioned structural parameters. Irradation at 1 or 10 cGy did not result in any significant changes in bone structural parameters. (3) Irradiation of 16-wk old male mice with high doses of 56Fe or proton (50 or 200cGy), but not at low doses (5 or 10cGy), showed a similar loss of cancellous BV/TV and trabecular number at five weeks post-IR. (4) Age-related bone loss overtook acute radiation-induced decrements in bone structure within four months post-IR with 100 cGy gamma and 12 months post-IR with 200 cGy iron. Transgenic mice globally overexpressing human catalase gene in mitochondria did not exhibit cancellous bone loss as assessed at four month post-IR with 10 cGy proton, 50 cGy iron, or in combination. (5) The cellular and molecular mechanisms responsible for loss of bone with radiation are mediated primarily through increased osteoclastogenesis. Our data provide evidence that there are increases in gene expression of TNF alpha and MCP1 in the bone marrow cells 24 hours post-IR and of osteoclastogenic differentiation factor RANKL by day 3. These cytokines in the marrow may stimulate mature osteoclasts or drive osteoclastogenesis from precursors. (6) Osteoblastogenesis from marrow progenitors evaluated ex vivo decreased following whole body 56Fe irradiation at a dose threshold between 20 and 50 cGy whereas osteoclastogenesis ex vivo increased with doses as low as 10cGy two days post-IR of mice. However, the latter finding was not observed in more than a single experiment. (7) Gamma irradiation of cells in vitro requires relatively high doses (200cGy) to disturb normal osteoblastogenesis and osteoclastogenesis as evidenced by decrements in mineralized nodule formation, osteoclast counts, and expression of osteoblast related genes such as runx2, col1a1. (8) We also investigated the effect of antioxidants on osteoblastogenesis following low dose in vitro gamma irradiation (15cGy) on day four bone marrow stromal cell cultures. Superoxide dismutase (SOD) was added to the cell culture medium for 2 or 3 days post-irradiation and cell colonies were counted on days 7 and 10. SOD treatment increased cell growth as measured by DNA content and colony forming units (CFU) in both irradiated cells and 0 cGy control groups. However, low dose radiation of 15cGy abolished SOD stimulatory effects on cell growth and CFU number. These results suggest that exogenous SOD increases osteoblast cell growth and colony formation and that low-dose radiation (15cGy) can interfere with the antioxidant effects. In summary, our findings indicate that acute, whole body irradiation at high doses (50-200 cGy) results in prompt tissue degradation and bone loss. Lower doses (<50 cGy) do not cause bone structural deterioration but may deplete stem/progenitor cell pools in the bone marrow.« less

Selective Enhancement of Systemic Th1 Immunity in Immunologically Immature Rats with an Orally Administered Bacterial Extract

PubMed Central

Bowman, L. M.; Holt, P. G.

2001-01-01

Infant rats primed during the first week of life with soluble antigen displayed adult-equivalent levels of T-helper 2 (Th2)-dependent immunological memory development as revealed by production of secondary immunoglobulin G1 (IgG1) antibody responses to subsequent challenge, but in contrast to adults failed to prime for Th1-dependent IgG2b responses. We demonstrate that this Th2 bias in immune function can be redressed by oral administration to neonates of a bacterial extract (Broncho-Vaxom OM-85) comprising lyophilized fractions of several common respiratory tract bacterial pathogens. Animals given OM-85 displayed a selective upregulation in primary and secondary IgG2b responses, accompanied by increased gamma interferon and decreased interleukin-4 production (both antigen specific and polyclonal), and increased capacity for development of Th1-dependent delayed hypersensitivity to the challenge antigen. We hypothesize that the bacterial extract functions via enhancement of the process of postnatal maturation of Th1 function, which is normally driven by stimuli from the gastrointestinal commensal microflora. PMID:11349036

Determining the Lorentz Factor and Viewing Angle of GRB 170817A

NASA Astrophysics Data System (ADS)

Zou, Yuan-Chuan; Wang, Fei-Fei; Moharana, Reetanjali; Liao, Bin; Chen, Wei; Wu, Qingwen; Lei, Wei-Hua; Wang, Fa-Yin

2018-01-01

The weak short gamma-ray burst (GRB) 170817A was accompanied by the GW170817 gravitational-wave event and is believed to have been produced by an off-beam relativistic jet. Here, we use the {E}{{p},{{i}}}{--}{E}{iso} and {{Γ }}{--}{E}{iso} relations to determine its Lorentz factor Γ and the viewing angle from the edge of the jet {θ }{obs}{\\prime } of GRB 170817A. Our results indicate that {{Γ }}={13.4}-5.5+9.8 and {θ }{obs}{\\prime }=4\\buildrel{\\circ}\\over{.} {3}-1.5+1.8, corresponding to an on-axis {E}{{p},{{i}}}={415}-167+361 {keV} and {E}{iso}=({2.4}-1.9+1.6)× {10}47 erg. Therefore, the GRB was an intrinsically weak short GRB. We also find that the afterglow emission was in good agreement with the follow-up multiband observations and that the radio emissions at around 20 days may have come from the off-axis jet. Interestingly, the Doppler factor and luminosity follow a universal relation for GRBs and blazars, thus suggesting that they may share a similar radiation mechanism.

Electroexcitation of the P33(1232), P11(1440), D13(1520), S11(1535) at Q{sup 2} = 0.4 and 0.65(GeV/c){sup 2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inna Aznauryan; Volker Burkert; Hovanes Egiyan

2004-07-01

Using two approaches: dispersion relations and isobar model, we have analyzed recent high precision CLAS data on cross sections of {pi}{sup 0}, {pi}{sup +}, and {eta} electroproduction on protons, and the longitudinally polarized electron beam asymmetry for p({rvec e},e{prime}p){pi}{sup 0} and p({rvec e},e{prime}p){pi}{sup +}. The contributions of the resonances P{sub 33}(1232), P{sub 11}(1440), D{sub 13}(1520), S{sub 11}(1535) to {pi} electroproduction and S{sub 11}(1535) to {eta} electroproduction are found. The results obtained in the two approaches are in good agreement with each other. There is also good agreement between amplitudes of the {gamma}* N {yields} S{sub 11}(1535) transition found in {pi}more » and {eta} electroproduction. For the first time accurate results are obtained for the longitudinal amplitudes of the P{sub 11}(1440), D{sub 13}(1520) and S{sub 11}(1535) electroexcitation on protons.« less

Preferential Targeting of Conserved Gag Regions after Vaccination with a Heterologous DNA Prime-Modified Vaccinia Virus Ankara Boost HIV-1 Vaccine Regimen.

PubMed

Bauer, Asli; Podola, Lilli; Mann, Philipp; Missanga, Marco; Haule, Antelmo; Sudi, Lwitiho; Nilsson, Charlotta; Kaluwa, Bahati; Lueer, Cornelia; Mwakatima, Maria; Munseri, Patricia J; Maboko, Leonard; Robb, Merlin L; Tovanabutra, Sodsai; Kijak, Gustavo; Marovich, Mary; McCormack, Sheena; Joseph, Sarah; Lyamuya, Eligius; Wahren, Britta; Sandström, Eric; Biberfeld, Gunnel; Hoelscher, Michael; Bakari, Muhammad; Kroidl, Arne; Geldmacher, Christof

2017-09-15

Prime-boost vaccination strategies against HIV-1 often include multiple variants for a given immunogen for better coverage of the extensive viral diversity. To study the immunologic effects of this approach, we characterized breadth, phenotype, function, and specificity of Gag-specific T cells induced by a DNA-prime modified vaccinia virus Ankara (MVA)-boost vaccination strategy, which uses mismatched Gag immunogens in the TamoVac 01 phase IIa trial. Healthy Tanzanian volunteers received three injections of the DNA-SMI vaccine encoding a subtype B and AB-recombinant Gag p37 and two vaccinations with MVA-CMDR encoding subtype A Gag p55 Gag-specific T-cell responses were studied in 42 vaccinees using fresh peripheral blood mononuclear cells. After the first MVA-CMDR boost, vaccine-induced gamma interferon-positive (IFN-γ + ) Gag-specific T-cell responses were dominated by CD4 + T cells ( P < 0.001 compared to CD8 + T cells) that coexpressed interleukin-2 (IL-2) (66.4%) and/or tumor necrosis factor alpha (TNF-α) (63.7%). A median of 3 antigenic regions were targeted with a higher-magnitude median response to Gag p24 regions, more conserved between prime and boost, compared to those of regions within Gag p15 (not primed) and Gag p17 (less conserved; P < 0.0001 for both). Four regions within Gag p24 each were targeted by 45% to 74% of vaccinees upon restimulation with DNA-SMI-Gag matched peptides. The response rate to individual antigenic regions correlated with the sequence homology between the MVA- and DNA Gag-encoded immunogens ( P = 0.04, r 2 = 0.47). In summary, after the first MVA-CMDR boost, the sequence-mismatched DNA-prime MVA-boost vaccine strategy induced a Gag-specific T-cell response that was dominated by polyfunctional CD4 + T cells and that targeted multiple antigenic regions within the conserved Gag p24 protein. IMPORTANCE Genetic diversity is a major challenge for the design of vaccines against variable viruses. While including multiple variants for a given immunogen in prime-boost vaccination strategies is one approach that aims to improve coverage for global virus variants, the immunologic consequences of this strategy have been poorly defined so far. It is unclear whether inclusion of multiple variants in prime-boost vaccination strategies improves recognition of variant viruses by T cells and by which mechanisms this would be achieved, either by improved cross-recognition of multiple variants for a given antigenic region or through preferential targeting of antigenic regions more conserved between prime and boost. Engineering vaccines to induce adaptive immune responses that preferentially target conserved antigenic regions of viral vulnerability might facilitate better immune control after preventive and therapeutic vaccination for HIV and for other variable viruses. Copyright © 2017 American Society for Microbiology.

Isatis tinctoria L. combined with co-stimulatory molecules blockade prolongs survival of cardiac allografts in alloantigen-primed mice.

PubMed

Kang, Xiangpeng; Chen, Jibing; Qin, Qing; Wang, Feng; Wang, Yongzhi; Lan, Tianshu; Xu, Shuo; Wang, Feiyu; Xia, Junjie; Ekberg, Henrik; Qi, Zhongquan; Liu, Zhongchen

2010-05-01

Memory T cells present a unique challenge in transplantation. Although memory T cells express robust immune responses to invading pathogens, they may be resistant to the effects of immunosuppressive therapies used to prolong graft survival. In previous studies, we found that compound K, the synthesized analogue of highly unsaturated fatty acids from Isatis tinctoria L., reduced acute cardiac allograft rejection in mice (Wang et al., 2009 [1]). Here, we further investigated the effect of compound K on cardiac allograft rejection in alloantigen-primed mice. We found that compound K significantly inhibited CD4(+) and CD8(+) memory T cells proliferation in a mixed lymphocyte reaction (MLR). In vivo, compound K combined with anti-CD154 and anti-LFA-1 monoclonal antibodies (mAbs) significantly extended the survival time of heart grafts in alloantigen-primed mice with no obvious toxic side effects. Furthermore, our data suggests that compound K works by reducing the expression of both IL-2 and IFN-gamma within the graft rather than enhancing expression of regulatory T cells (Tregs). Compound K can also inhibit the alloresponses of memory T cells, while increasing the proportion of CD4(+) memory T cells in the spleen of the recipients and significantly reducing the level of alloantibodies in the serum. Our study highlights the unique immune effects of compound K that may be further explored for clinical use in extending the survival of transplant grafts. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Late effects of radiation on the lumbar spinal cord of guinea pigs: Re-treatment tolerance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mason, K.A.; Withers, H.R.; Chiang, Chi-Shiun

Using a guinea pig model of lumbar myelopathy, various factors affecting the tolerance of spinal cord to irradiation were assessed: (a) extent of initial injury; (b) time interval between priming and test doses; and (c) animal age at the time of initial radiation treatment. A 3 cm section of lumbar spinal cord of guinea pigs was irradiated with fractionated doses of 4.5 Gy gamma rays given as 9 fractions per week. Guinea pigs were primed with 9 x 4.5 Gy in 7 days which is 60% of the ED[sub 50] for a continuous course of treatment. After 28 or 40more » weeks, animal were retreated with 6-14 fractions of 4.5 Gy. Animals were observed for 2 years following the priming dose and both the incidence and latency of myelopathy recorded. Young adult guinea pigs (8 wk old) showed both a decreased radiation tolerance and latency compared to old individuals (40 wk old). At 28 or 40 wk after 9 x 4.5 Gy, only about 8% of the initial injury was remembered in young adult guinea pigs. The amount of residual injury was dependent on the initial damage as a proportion of the tolerance dose. The spinal cord shows a greater capacity for long-term recovery than generally appreciated and re-treatment doses clinically prescribed may be lower than necessary. 8 refs., 3 figs., 2 tabs.« less

Different levels of immunogenicity of two strains of Fowlpox virus as recombinant vaccine vectors eliciting T-cell responses in heterologous prime-boost vaccination strategies.

PubMed

Cottingham, Matthew G; van Maurik, Andre; Zago, Manola; Newton, Angela T; Anderson, Richard J; Howard, M Keith; Schneider, Jörg; Skinner, Michael A

2006-07-01

The FP9 strain of F has been described as a more immunogenic recombinant vaccine vector than the Webster FPV-M (FPW) strain (R. J. Anderson et al., J. Immunol. 172:3094-3100, 2004). This study expands the comparison to include two separate recombinant antigens and multiple, rather than single, independent viral clones derived from the two strains. Dual-poxvirus heterologous prime-boost vaccination regimens using individual clones of recombinant FP9 or FPW in combination with recombinant modified V Ankara expressing the same antigen were evaluated for their ability to elicit T-cell responses against recombinant antigens from Plasmodium berghei (circumsporozoite protein) or human immunodeficiency virus type 1 (a Gag-Pol-Nef fusion protein). Gamma interferon enzyme-linked immunospot assay and fluorescence-activated cell sorting assays of the responses to specific epitopes confirmed the approximately twofold-greater cellular immunogenicity of FP9 compared to FPW, when given as the priming or boosting immunization. Equality of transgene expression in mouse cells infected with the two strains in vitro was verified by Western blotting. Directed partial sequence analysis and PCR analysis of FPW and comparison to available whole-genome sequences revealed that many loci that are mutated in the highly attenuated and culture-adapted FP9 strain are wild type in FPW, including the seven multikilobase deletions. These "passage-specific" alterations are hypothesized to be involved in determining the immunogenicity of fowlpox virus as a recombinant vaccine vector.

Iron-nickel-chromium alloy having improved swelling resistance and low neutron absorbence

DOEpatents

Korenko, Michael K.

1986-01-01

An iron-nickel-chromium age-hardenable alloy suitable for use in fast breeder reactor ducts and cladding which utilizes the gamma-double prime strengthening phase and characterized in having a delta or eta phase distributed at or near grain boundaries. The alloy consists essentially of about 33-39.5% nickel, 7.5-16% chromium, 1.5-4% niobium, 0.1-0.7% silicon, 0.01-0.2% zirconium, 1-3% titanium, 0.2-0.6% aluminum, and the remainder essentially all iron. Up to 0.4% manganese and up to 0.010% magnesium can be added to inhibit trace element effects.

Chlamydia trachomatis Is Resistant to Inclusion Ubiquitination and Associated Host Defense in Gamma Interferon-Primed Human Epithelial Cells.

PubMed

Haldar, Arun K; Piro, Anthony S; Finethy, Ryan; Espenschied, Scott T; Brown, Hannah E; Giebel, Amanda M; Frickel, Eva-Maria; Nelson, David E; Coers, Jörn

2016-12-13

The cytokine gamma interferon (IFN-γ) induces cell-autonomous immunity to combat infections with intracellular pathogens, such as the bacterium Chlamydia trachomatis The present study demonstrates that IFN-γ-primed human cells ubiquitinate and eliminate intracellular Chlamydia-containing vacuoles, so-called inclusions. We previously described how IFN-γ-inducible immunity-related GTPases (IRGs) employ ubiquitin systems to mark inclusions for destruction in mouse cells and, furthermore, showed that the rodent pathogen Chlamydia muridarum blocks ubiquitination of its inclusions by interfering with mouse IRG function. Here, we report that ubiquitination of inclusions in human cells is independent of IRG and thus distinct from the murine pathway. We show that C. muridarum is susceptible to inclusion ubiquitination in human cells, while the closely related human pathogen C. trachomatis is resistant. C. muridarum, but not C. trachomatis, inclusions attract several markers of cell-autonomous immunity, including the ubiquitin-binding protein p62, the ubiquitin-like protein LC3, and guanylate-binding protein 1. Consequently, we find that IFN-γ priming of human epithelial cells triggers the elimination of C. muridarum, but not C. trachomatis, inclusions. This newly described defense pathway is independent of indole-2,3-dioxygenase, a known IFN-γ-inducible anti-Chlamydia resistance factor. Collectively, our observations indicate that C. trachomatis evolved mechanisms to avoid a human-specific, ubiquitin-mediated response as part of its unique adaptation to its human host. Chlamydia trachomatis is the leading cause of sexually transmitted bacterial infections and responsible for significant morbidity, including pelvic inflammatory disease, infertility, and ectopic pregnancies in women. As an obligate intracellular pathogen, C. trachomatis is in perpetual conflict with cell-intrinsic defense programs executed by its human host. Our study defines a novel anti-Chlamydia host resistance pathway active in human epithelial cells. This defense program promotes the deposition of the small antimicrobial protein ubiquitin on vacuoles containing Chlamydia We show that this ubiquitin-based resistance pathway of human cells is highly effective against a Chlamydia species adapted to rodents but ineffective against human-adapted C. trachomatis This observation indicates that C. trachomatis evolved strategies to avoid entrapment within ubiquitin-labeled vacuoles as part of its adaptation to the human innate immune system. Copyright © 2016 Haldar et al.

Kiglapait Feldspar States 5 to <2 Kbar, 1250 to 240 Degrees C in 20 Ma: Liquidus, Solidus, Solvi, and Subsolidus with Sr Isotope Partitioning: a Review

NASA Astrophysics Data System (ADS)

Morse, S. A.

2017-12-01

The 1305 Ga Kiglapait Intrusion of coastal Labrador records the crystallization of troctolite through olivine gabbro to magnetite- and apatite-bearing rocks to monoclinic sanidine- mesoperthite-ferrosyenite below an inverted stratigraphy of a thin Upper Border Zone. The crystallization history was about 1 Ma. ¶The evolutionary history of Kiglapait feldspars in an 8.4 km thick magma chamber runs from plagioclase An70 at 5 kbar and 1250°C, cooling through to ferrosyenite with mesoperthite and two feldspars at 3 kbar and 1,000°C. The residual magma encountered the binodal solvus and finished crystallizing as an azeotrope with plagioclase (Or 21, An 15) and sanidine (Or 52, An 8) in liquid (Xor = 1/3; An 11). Cooling in the subsolidus brought the feldspars to compositions An15-Or 3, An0-Or 80-85 at 800-730°C. Metastable mesoperthite on the coherent solvus in various stages of late equilibration persists in the local assemblages. Arrested to complete feldspar symplectites suggest the local presence of a vapor phase. ¶Splits of the final Or-rich feldspar were found by mass spectrometry to have a dominant quantity of Rb and 87Sr/86Sr along with % amounts of Ba; in contrast, the plag fraction has very low Rb and 87Sr/86Sr. The estimated timing of the isotopic segregation was plausibly continuous with major-element fractionation or perhaps at the moment(s) of exsolution. ¶The cooling record of the solidified intrusion at 3 kbar is shown by 40Ar/39Ar data to have been rapid, reaching an ambient temperature near 240°C within the first 20 Ma, compared to the ambient country-rock temperature before intrusion of 350°C. The difference suggests a late uplift of the region after the Kiglapait magmatism. ¶Contributions from Y. Yu, T. Krogh, M. Hamilton, D. Lindsley, D. DePaolo, M. Jercinovic and S.R. Hart are especially acknowledged.

A study of Laser Shock Peening on Fatigue behavior of IN718Plus Superalloy: Simulations and Experiments

NASA Astrophysics Data System (ADS)

Chaswal, Vibhor

Laser shock peening (LSP) for improving fatigue life of IN718Plus superalloy is investigated. Fatigue geometry and LSP parameters were optimized using finite element method (FEM). Residual stress distributions estimated by FEM were validated using Synchrotron XRD and line focus lab XRD, and correlated with microhardness. An eigenstrain analysis of LSP induced edge deflections (measured with optical interferometry) was also conducted. Transmission electron microscopy (TEM) of single-spot LSP coupons shows sudden increase in dislocation density under LSP treated region. Total life fatigue was conducted at R=0.1 at 298K and 923K, with and without LSP. S-N curve endurance limit increases at both temperatures with FEM optimized LSP samples. Based on TEM of fatigue microstructure and LSP coupons, a mechanistic description of observed fatigue improvement is attempted. Often need arises to weld components, and weld heat-affected-zone reaches near-solvus temperatures. To simulate this treatment, sub-solvus hot-rolled IN718Plus is aged at 923K. We observe precipitation of thin eta-Ni3(Al, Ti) plates after 1000 hours, making the material susceptible to cracks, and lowering fatigue life. Effect of LSP on fatigue crack growth (FCG) is studied following ASTM guidelines on M(T) geometry at R=0.1. Acceleration in FCG rate with LSP is observed for this geometry and LSP condition. Prior FEM optimization was not conducted for FCG tests, and may account for lower FCG resistance after LSP. FCG results were corroborated with COD compliance based analysis. Crack measurements were done using potential drop method, and crack closure was analyzed. Effect of LSP on overload FCG was investigated by single-cycle 100% overload followed by single-spot LSP on the crack-tip plastic zone. Crack retardation occurs after application of overload+LSP. Effective contribution of overload+LSP to crack retardation is estimated. Fractographic analysis of LSP treated fatigue samples suggests sub-surface crack nucleation, and is analyzed based on stress concentration behavior of small cracks.

North Polar Water Ice by Weight

NASA Technical Reports Server (NTRS)

2003-01-01

December 8, 2003

This map shows the percent of water by weight in near-surface materials of Mars' north polar region. It is derived from the gamma ray spectrometer component of the gamma ray spectrometer suite of instruments on NASA's Mars Odyssey spacecraft.

Significant concentrations of water (greater than 20 percent) are poleward of 55 degrees north latitude. The highest concentration, greater than 50 percent, is between 75 degrees north and the pole. Another area with a high concentration of water by weight is in the north polar plains between longitudes minus 105 degrees and minus 140 degrees, and between latitudes 60 degrees and 75 degrees.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the 2001 Mars Odyssey mission for the NASA Office of Space Science in Washington. Investigators at Arizona State University in Tempe, the University of Arizona in Tucson and NASA's Johnson Space Center, Houston, operate the science instruments. The gamma-ray spectrometer was provided by the University of Arizona in collaboration with the Russian Aviation and Space Agency, which provided the high-energy neutron detector, and the Los Alamos National Laboratories, New Mexico, which provided the neutron spectrometer. Lockheed Martin Space Systems, Denver, is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL.

Map of Martian Thorium at Mid-Latitudes

NASA Technical Reports Server (NTRS)

2003-01-01

This gamma ray spectrometer map of the mid-latitude region of Mars is based on gamma-rays from the element thorium. Thorium is a naturally radioactive element that exists in rocks and soils in extremely small amounts. The region of highest thorium content, shown in red, is found in the northern part of Acidalia Planitia (50 degrees latitude, -30 degrees longitude). Areas of low thorium content, shown in blue, are spread widely across the planet with significant low abundances located to the north of Olympus Mons (near 55 degrees latitude, -155 degrees longitude), to the east of the Tharsis volcanoes (-10 degrees latitude, -80 degrees longitude) and to the south and east of Elysium Mons (20 degrees latitude, 160 degrees longitude). Contours of constant surface elevation are also shown. The long continuous contour line running from east to west marks the approximate separation of the younger lowlands in the north from the older highlands in the south.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The gamma ray spectrometer was provided by the University of Arizona, Tucson. Lockheed Martin Astronautics, Denver, Colo., is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Pathway for biodegradation of p-nitrophenol in a Moraxella sp

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spain, J.C.; Gibson, D.T.

1991-03-01

A Moraxella strain grew on p-nitrophenol with stoichiometric release of nitrite. During induction of the enzymes for growth on p-nitrophenol, traces of hydroquinone accumulated in the medium. In the presence of 2,2{prime}-dipyidyl, p-nitrophenol, was converted stoichiometrically to hydroquinone. Particulate enzymes catalyzed the conversion of p-nitrophenol to hydroquinone in the presence of NADPH and oxygen. Soluble enzymes catalyzed the conversion of hydroquinone to {gamma}-hydroxymuconic semialdehyde, which was identified by high-performance liquid chromatography (HPLC)-mass spectroscopy. Upon addition of catalytic amounts of NAD{sup +}, {gamma}-hydroxymuconic semialdehyde was converted to {beta}-ketoadipic acid. In the presence of pyruvate and lactic dehydrogenase, substrate amounts of NADmore » were required and {gamma}-hydroxymuconic semialdehyde was converted to maleylacetic acid, which was identified by HPLC-mass spectroscopy. Similar results were obtained when the reaction was carried out in the presence of potassium ferricyanide. Extracts prepared from p-nitrophenol-grown cells also contained an enzyme that catalyzed the oxidation of 1,2,4-benzenetriol to maleylacetic acid. The enzyme responsible for the oxidation of 1,2,4-benzenetriol was separated from the enzyme responsible for hydroquinone oxidation by DEAE-cellulose chromatography. The results indicate that the pathway for biodegradation of p-nitrophenol involves the initial removal of the nitro group as nitrite and formation of hydroquinone.« less

Map of Martian Potassium at Mid-Latitudes

NASA Technical Reports Server (NTRS)

2003-01-01

This gamma ray spectrometer map of the mid-latitude region of Mars is based on gamma-rays from the element potassium. Potassium, having the chemical symbol K, is a naturally radioactive element and is a minor constituent of rocks on the surface of both Mars and Earth. The region of highest potassium content, shown in red, is concentrated in the northern part of Acidalia Planitia (centered near 55 degrees N, -30 degrees). Several areas of low potassium content, shown in blue, are distributed across the mid-latitudes, with two significant low concentrations, one associated with the Hellas Basin (centered near 35 degrees S, 70 degrees) and the other lying southeast of Elysium Mons (centered near 10 degrees N, 160 degrees). Contours of constant surface elevation are also shown. The long continuous line running from east to west marks the approximate separation of the younger lowlands in the north from the older highlands in the south.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The gamma ray spectrometer was provided by the University of Arizona, Tucson. Lockheed Martin Astronautics, Denver, is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Effect of reduction of strategic Columbium addition in 718 Alloy on the structure and properties

NASA Technical Reports Server (NTRS)

Ziegler, K. R.; Wallace, J. F.

1985-01-01

A series of alloys was developed having a base composition similar to Inconel 718, with reduced Cb levels of 3.00 and 1.10 wt% Cb. Substitutions of 3.0% W, 3.0W + 0.9V or Mo increased from 3.0% to 5.8% were made for the Cb in these alloys. Two additional alloys, one containing 3.49% Cb and 1.10% Ti and another containing 3.89% Cb and 1.29% Ti were also studied. Tensile properties at rooom and elevated temperatures, stress-rupture tests, and an analysis of extracted phases were carried out for each of the alloys. Additions of solid solution elements to a reduced Cb alloy had no significant effect on the properties of the alloys under either process condition. The solution and age alloys with substitutions of 1.27% i at 3.89% Cb had tensile properties similar top hose of the original alloy and stress-rupture properties superior to the original alloy. The improved stress-rupture properties were the result of significant precipitation of Ni3Ti-gamma prime in the alloy, which is more stable than gamma' at the elevated temperatures. At lower temperatures, the new alloy benefits from gamma' strengthening. With more precise control and proper processing, the reduced Cb direct-age alloy could substitute for Alloy 718 in high strength applications.

Nuclear Structure of the Closed Subshell Nucleus 90Zr Studied with the (n,n'(gamma)) Reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garrett, P E; Younes, Y; Becker, J A

States in {sup 90}Zr have been observed with the (n,n{prime}{gamma}) reaction using both spallation and monoenergetic accelerator-produced neutrons. A scheme comprised of 81 levels and 157 transitions was constructed concentrating on levels below 5.6 MeV in excitation energy. Spins have been determined by considering data from all experimental studies performed for {sup 90}Zr. Lifetimes have been deduced using the Doppler-shift attenuation method for many of the states and transition rates have been obtained. A spherical shell-model interpretation in terms of particle-hole excitations assuming a {sup 88}Sr closed core is given. In some cases, enhancements in B(M1) and B(E2) values aremore » observed that cannot be explained by assuming simple particle-hole excitations. Shell-model calculations using an extended f pg-shell model space reproduce the spectrum of excited states very well, and the gross features of the B(M1) and B(E2) transition rates. Transition rates for individual levels show discrepancies between calculations and experimental values.« less

Prime-boost BCG vaccination with DNA vaccines based in β-defensin-2 and mycobacterial antigens ESAT6 or Ag85B improve protection in a tuberculosis experimental model.

PubMed

Cervantes-Villagrana, Alberto R; Hernández-Pando, Rogelio; Biragyn, Arya; Castañeda-Delgado, Julio; Bodogai, Monica; Martínez-Fierro, Margarita; Sada, Eduardo; Trujillo, Valentin; Enciso-Moreno, Antonio; Rivas-Santiago, Bruno

2013-01-11

The World Health Organization (WHO) has estimated that there are about 8 million new cases annually of active Tuberculosis (TB). Despite its irregular effectiveness (0-89%), the Bacillus Calmette-Guérin) BCG is the only vaccine available worldwide for prevention of TB; thus, the design is important of novel and more efficient vaccination strategies. Considering that β-defensin-2 is an antimicrobial peptide that induces dendritic cell maturation through the TLR-4 receptor and that both ESAT-6 and Ag85B are immunodominant mycobacterial antigens and efficient activators of the protective immune response, we constructed two DNA vaccines by the fusion of the gene encoding β-defensin-2 and antigens ESAT6 (pDE) and 85B (pDA). After confirming efficient local antigen expression that induced high and stable Interferon gamma (IFN-γ) production in intramuscular (i.m.) vaccinated Balb/c mice, groups of mice were vaccinated with DNA vaccines in a prime-boost regimen with BCG and with BCG alone, and 2 months later were challenged with the mild virulence reference strain H37Rv and the highly virulent clinical isolate LAM 5186. The level of protection was evaluated by survival, lung bacilli burdens, and extension of tissue damage (pneumonia). Vaccination with both DNA vaccines showed similar protection to that of BCG. After the challenge with the highly virulent Mycobacterium tuberculosis strain, animals that were prime-boosted with BCG and then boosted with both DNA vaccines showed significant higher survival and less tissue damage than mice vaccinated only with BCG. These results suggest that improvement of BCG vaccination, such as the prime-boost DNA vaccine, represents a more efficient vaccination scheme against TB. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mucosal prior to systemic application of recombinant adenovirus boosting is more immunogenic than systemic application twice but confers similar protection against SIV-challenge in DNA vaccine-primed macaques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schulte, Reiner; Suh, You-Suk; Sauermann, Ulrike

2009-01-20

We investigated the immunogenicity and efficacy of a bimodal prime/boost vaccine regimen given by various routes in the Simian immunodeficiency virus (SIV) rhesus monkey model for AIDS. Twelve animals were immunized with SIV DNA-vectors followed by the application of a recombinant adenovirus (rAd5) expressing the same genes either intramuscularly (i.m.) or by oropharyngeal spray. The second rAd5-application was given i.m. All vaccinees plus six controls were challenged orally with SIVmac239 12 weeks post-final immunization. Both immunization strategies induced strong SIV Gag-specific IFN-{gamma} and T-cell proliferation responses and mediated a conservation of CD4{sup +} memory T-cells and a reduction of viralmore » load during peak viremia following infection. Interestingly, the mucosal group was superior to the systemic group regarding breadth and strength of SIV-specific T-cell responses and exhibited lower vector specific immune responses. Therefore, our data warrant the inclusion of mucosal vector application in a vaccination regimen which makes it less invasive and easier to apply.« less

Flexible mini gamma camera reconstructions of extended sources using step and shoot and list mode.

PubMed

Gardiazabal, José; Matthies, Philipp; Vogel, Jakob; Frisch, Benjamin; Navab, Nassir; Ziegler, Sibylle; Lasser, Tobias

2016-12-01

Hand- and robot-guided mini gamma cameras have been introduced for the acquisition of single-photon emission computed tomography (SPECT) images. Less cumbersome than whole-body scanners, they allow for a fast acquisition of the radioactivity distribution, for example, to differentiate cancerous from hormonally hyperactive lesions inside the thyroid. This work compares acquisition protocols and reconstruction algorithms in an attempt to identify the most suitable approach for fast acquisition and efficient image reconstruction, suitable for localization of extended sources, such as lesions inside the thyroid. Our setup consists of a mini gamma camera with precise tracking information provided by a robotic arm, which also provides reproducible positioning for our experiments. Based on a realistic phantom of the thyroid including hot and cold nodules as well as background radioactivity, the authors compare "step and shoot" (SAS) and continuous data (CD) acquisition protocols in combination with two different statistical reconstruction methods: maximum-likelihood expectation-maximization (ML-EM) for time-integrated count values and list-mode expectation-maximization (LM-EM) for individually detected gamma rays. In addition, the authors simulate lower uptake values by statistically subsampling the experimental data in order to study the behavior of their approach without changing other aspects of the acquired data. All compared methods yield suitable results, resolving the hot nodules and the cold nodule from the background. However, the CD acquisition is twice as fast as the SAS acquisition, while yielding better coverage of the thyroid phantom, resulting in qualitatively more accurate reconstructions of the isthmus between the lobes. For CD acquisitions, the LM-EM reconstruction method is preferable, as it yields comparable image quality to ML-EM at significantly higher speeds, on average by an order of magnitude. This work identifies CD acquisition protocols combined with LM-EM reconstruction as a prime candidate for the wider introduction of SPECT imaging with flexible mini gamma cameras in the clinical practice.

Geochemistry at 4 Vesta: Observations Using Fast Neutrons

NASA Technical Reports Server (NTRS)

Lawrence, David J.; Prettyman, Thomas H.; Feldman, William C.; Bazell, David; Mittlefehldt, David W.; Peplowski, Patrick N.; Reedy, Robert C.

2012-01-01

Dawn is currently in orbit around the asteroid 4 Vesta, and one of the major objectives of the mission is to probe the relationship of Vesta to the Howardite, Eucrite, and Diogenite (HED) meteorites. As Vesta is an example of a differentiated planetary embryo, Dawn will also provide fundamental information about planetary evolution in the early solar system [1]. To help accomplish this overall goal, the Dawn spacecraft carries the Gamma-Ray and Neutron Detector (GRaND). GRaND uses planetary gamma-ray and neutron spectroscopy to measure the surface elemental composition of Vesta and will provide information that is unique and complementary to that provided by the other Dawn instruments and investigations. Gamma-ray and neutron spectroscopy is a standard technique for measuring planetary compositions [2], having successfully made measurements at near-Earth asteroids, the Moon, Mars, Mercury and now Vesta. GRaND has made the first measurements of the neutron spectrum from any asteroid (previous asteroid measurements were only made with gamma-rays). Dawn has been collecting data at Vesta since July 2011. The prime data collection period for GRaND is the Low-Altitude Mapping Orbit (LAMO), which started on 12 December 2011 and will last through spring 2012. During LAMO, the Dawn spacecraft orbits at an average altitude of 210 km above the surface of Vesta, which allows good neutron and gamma-ray signals to be detected from Vesta. A description of the overall goals of GRaND and a summary of the initial findings are given elsewhere [3,4]. The subject of this study is to present the information that will be returned from GRaND using fast neutron measurements. Here, we discuss what fast neutrons can reveal about Vesta s surface composition, how such data can address Dawn science goals, and describe fast neutron measurements made in the early portion of the Vesta LAMO phase.

Snapshots of the maltose transporter during ATP hydrolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oldham, Michael L.; Chen, Jue

2011-12-05

ATP-binding cassette transporters are powered by ATP, but the mechanism by which these transporters hydrolyze ATP is unclear. In this study, four crystal structures of the full-length wild-type maltose transporter, stabilized by adenosine 5{prime}-({beta},{gamma}-imido)triphosphate or ADP in conjunction with phosphate analogs BeF{sub 3}{sup -}, VO{sub 4}{sup 3-}, or AlF{sub 4}{sup -}, were determined to 2.2- to 2.4-{angstrom} resolution. These structures led to the assignment of two enzymatic states during ATP hydrolysis and demonstrate specific functional roles of highly conserved residues in the nucleotide-binding domain, suggesting that ATP-binding cassette transporters catalyze ATP hydrolysis via a general base mechanism.

Observations of directional gamma prime coarsening during engine operation

NASA Astrophysics Data System (ADS)

Draper, S.; Hull, D.; Dreshfield, R.

1989-04-01

Two alloys, NASAIR 100 and a modified NASAIR 100 called Alloy 3, were run as turbine blades in an experimental ground-based Garrett TFE731 engine for up to 200 hours. The stress induced directional coarsening of γ' (rafting) that developed during engine testing was analyzed and compared to previous research from laboratory tests. The blades were found to have formed a lamellar structure, the lamellae being normal to the centrifugal stress axis over much of the span. However, near the surfaces, the blades were found to have formed lamellae parallel to the centrifugal stress axis for certain cycles. Representative photomicrographs of the blades and the effects of stress and temperature on lamellae formation are shown.

Characterization of CD4 and CD8 T Cell Responses in MuSK Myasthenia Gravis

PubMed Central

Yi, JS; Guidon, A; Sparks, S; Osborne, R; Juel, VC; Massey, JM; Sanders, DB; Weinhold, KJ; Guptill, JT

2014-01-01

Muscle specific tyrosine kinase myasthenia gravis (MuSK MG) is a form of autoimmune MG that predominantly affects women and has unique clinical features, including prominent bulbar weakness, muscle atrophy, and excellent response to therapeutic plasma exchange. Patients with MuSK MG have predominantly IgG4 autoantibodies directed against MuSK on the postsynaptic muscle membrane. Lymphocyte functionality has not been reported in this condition. The goal of this study was to characterize T-cell responses in patients with MuSK MG. Intracellular production of IFN-gamma, TNF-alpha, IL-2, IL-17, and IL-21 by CD4+ and CD8+ T-cells was measured by polychromatic flow cytometry in peripheral blood samples from 11 Musk MG patients and 10 healthy controls. Only one MuSK MG patient was not receiving immunosuppressive therapy. Regulatory T-cells (Treg) were also included in our analysis to determine if changes in T cell function were due to altered Treg frequencies. CD8+ T-cells from MuSK MG patients had higher frequencies of polyfunctional responses than controls, and CD4+ T-cells had higher IL-2, TNF-alpha, and IL-17. MuSK MG patients had a higher percentage of CD4+ T-cells producing combinations of IFN-gamma/IL-2/TNF-gamma, TNF-alpha/IL-2, and IFN-gamma/TNF-alpha. Interestingly, Treg numbers and CD39 expression were not different from control values. MuSK MG patients had increased frequencies of Th1 and Th17 cytokines and were primed for polyfunctional proinflammatory responses that cannot be explained by a defect in Treg function or number. PMID:24378287

A missing population of short duration gamma-ray bursts

NASA Astrophysics Data System (ADS)

Troja, Eleonora

Short duration gamma-ray bursts (GRBs) are brief and intense flashes of gamma-ray radiation located at cosmological distances. NASA s Swift mission provided the first breakthrough observations connecting these high-energy transients to the coalescence of two compact objects, either two neutron stars (NSs) or a NS and a black hole (BH). Short GRBs are therefore prime candidate electromagnetic counterparts of gravitational wave sources detectable by advanced LIGO. Unfortunately, only a fraction of short GRBs visible by Swift is promptly identified by the on-board trigger system. A larger number of events fails to pass the on-board trigger selection and goes unnoticed. Luckily, this subset of events is not lost. It is instead downlinked through a low-priority channel and then archived. The goal of this ADAP proposal is to harvest this rich population of gamma-ray transients buried in the data archive. We propose to 1) systematically mine this untapped resource of the Swift archive in order to discover new short GRBs; 2) correlate the Swift untriggered dataset with signals detected by other facilities (e.g Fermi, INTEGRAL), at other wavelengths (e.g. fast radio bursts) or with other messengers (e.g. gravitational waves); 3) develop and release the relevant tools and documentation to the community in order to facilitate the exploitation of this valuable dataset in future years. The proposed research will significantly expand the current database of short GRBs, and aid multimessenger searches of transient phenomena. By studying the behavior of matter in extreme physical conditions, the formation of new black holes, and gravity, this project directly addresses NASA Strategic Objective 1.6, a key science goal in the area of Cosmic Origins.

Vaccination of metastatic colorectal cancer patients with matured dendritic cells loaded with multiple major histocompatibility complex class I peptides.

PubMed

Kavanagh, Brian; Ko, Andrew; Venook, Alan; Margolin, Kim; Zeh, Herbert; Lotze, Michael; Schillinger, Brian; Liu, Weihong; Lu, Ying; Mitsky, Peggie; Schilling, Marta; Bercovici, Nadege; Loudovaris, Maureen; Guillermo, Roy; Lee, Sun Min; Bender, James; Mills, Bonnie; Fong, Lawrence

2007-10-01

Developing a process to generate dendritic cells (DCs) applicable for multicenter trials would facilitate cancer vaccine development. Moreover, targeting multiple antigens with such a vaccine strategy could enhance the efficacy of such a treatment approach. We performed a phase 1/2 clinical trial administering a DC-based vaccine targeting multiple tumor-associated antigens to patients with advanced colorectal cancer (CRC). A qualified manufacturing process was used to generate DC from blood monocytes using granulocyte macrophage colony-stimulating factor and IL-13, and matured for 6 hours with Klebsiella-derived cell wall fraction and interferon-gamma (IFN-gamma). DCs were also loaded with 6 HLA-A*0201 binding peptides derived from carcinoembryonic antigen (CEA), MAGE, and HER2/neu, as well as keyhole limpet hemocyanin protein and pan-DR epitope peptide. Four planned doses of 35x10(6) cells were administered intradermally every 3 weeks. Immune response was assessed by IFN-gamma enzyme-linked immunosorbent spot (ELISPOT). Matured DC possessed an activated phenotype and could prime T cells in vitro. In the trial, 21 HLA-A2+ patients were apheresed, 13 were treated with the vaccine, and 11 patients were evaluable. No significant treatment-related toxicity was reported. T-cell responses to a CEA-derived peptide were detected by ELISPOT in 3 patients. T cells induced to CEA possessed high avidity T-cell receptors. ELISPOT after in vitro restimulation detected responses to multiple peptides in 2 patients. All patients showed progressive disease. This pilot study in advanced CRC patients demonstrates DC-generated granulocyte macrophage colony-stimulating factor and IL-13 matured with Klebsiella-derived cell wall fraction and IFN-gamma can induce immune responses to multiple tumor-associated antigens in patients with advanced CRC.

Microstructure, Lattice Misfit, and High-Temperature Strength of γ'-Strengthened Co-Al-W-Ge Model Superalloys

NASA Astrophysics Data System (ADS)

Zenk, Christopher H.; Bauer, Alexander; Goik, Philip; Neumeier, Steffen; Stone, Howard J.; Göken, Mathias

2016-05-01

The quaternary alloy system Co-Al-W-Ge was investigated and it was found that a continuous γ /γ ^' two-phase field extends between the systems Co-Al-W and Co-Ge-W. All alloys examined comprised cuboidal L1_2 precipitates coherently embedded in an A1 matrix. Differential scanning calorimetry measurements revealed that the liquidus, solidus, and γ ^' -solvus temperatures decrease when the Ge content is increased. The lower liquidus temperature and the capability of γ ^' -strengthening in the Ge-rich alloys make them interesting as potential candidates for brazing applications of Co-base superalloys. The γ /γ ^' lattice misfit was determined by high-resolution X-ray diffraction and found to be positive for all alloys investigated, decreasing with increasing Ge content. The mechanical properties of the Al-rich alloys surpass those rich in Ge.

Molybdenum-titanium phase diagram evaluated from ab initio calculations

NASA Astrophysics Data System (ADS)

Barzilai, Shmuel; Toher, Cormac; Curtarolo, Stefano; Levy, Ohad

2017-07-01

The design of next generation β -type titanium implants requires detailed knowledge of the relevant stable and metastable phases at temperatures where metallurgical heat treatments can be performed. Recently, a standard specification for surgical implant applications was established for Mo-Ti alloys. However, the thermodynamic properties of this binary system are not well known and two conflicting descriptions of the β -phase stability have been presented in the literature. In this study, we use ab initio calculations to investigate the Mo-Ti phase diagram. These calculations predict that the β phase is stable over a wide concentration range, in qualitative agreement with one of the reported phase diagrams. In addition, they predict stoichiometric compounds, stable at temperatures below 300 ∘C , which have not yet been detected by experiments. The resulting solvus, which defines the transition to the β -phase solid solution, therefore occurs at lower temperatures and is more complex than previously anticipated.

Gamma Prime Precipitate Evolution During Aging of a Model Nickel-Based Superalloy

NASA Astrophysics Data System (ADS)

Goodfellow, A. J.; Galindo-Nava, E. I.; Christofidou, K. A.; Jones, N. G.; Martin, T.; Bagot, P. A. J.; Boyer, C. D.; Hardy, M. C.; Stone, H. J.

2018-03-01

The microstructural stability of nickel-based superalloys is critical for maintaining alloy performance during service in gas turbine engines. In this study, the precipitate evolution in a model polycrystalline Ni-based superalloy during aging to 1000 hours has been studied via transmission electron microscopy, atom probe tomography, and neutron diffraction. Variations in phase composition and precipitate morphology, size, and volume fraction were observed during aging, while the constrained lattice misfit remained constant at approximately zero. The experimental composition of the γ matrix phase was consistent with thermodynamic equilibrium predictions, while significant differences were identified between the experimental and predicted results from the γ' phase. These results have implications for the evolution of mechanical properties in service and their prediction using modeling methods.

Effects of baclofen and raclopride on reinstatement of cocaine self-administration in the rat.

PubMed

Froger-Colléaux, Christelle; Castagné, Vincent

2016-04-15

At present there is no satisfactory treatment against relapse of drug-seeking behavior. Relapse can be modeled in laboratory animals using reinstatement procedures, whereby previously extinguished self-administration for a drug is reinstated by different factors, such as exposure to cues or drug priming. It is thought that activation of gamma-aminobutyric acid (GABA) B receptor complexes could represent a promising approach to pharmacotherapy for diminishing relapse potential with drugs possessing reinforcing properties. The effects of baclofen (a prototypic GABAB receptor agonist) on cue-induced cocaine reinstatement were evaluated in the rat with or without a priming injection of cocaine. The effects of raclopride (an antagonist of dopamine D2 receptors) were also evaluated. Cue-induced reinstatement under vehicle resulted in a significant increase in the number of presses on the active lever, as compared with extinction lever responding. This effect was accentuated in rats receiving a priming injection of cocaine (cocaine-plus-cue-induced reinstatement). Baclofen, at doses without effects on food-motivated operant behavior (2.5 and 5mg/kg i.p.), dose-dependently decreased the number of active lever presses during cue-induced reinstatement. Baclofen had slightly weaker effects on cocaine-plus-cue-induced reinstatement. Raclopride (0.08 and 0.15 mg/kg s.c.) had similar effects against cue-induced reinstatement although it failed to inhibit cocaine-plus-cue-induced reinstatement at the lower dose. Baclofen dose-dependently and selectively decreased reinstatement of cocaine self-administration. The data obtained provide support for the potential anti-craving efficacy of baclofen in the treatment of cocaine drug-seeking. Copyright © 2016 Elsevier B.V. All rights reserved.

Investigating the Role of TNF-α and IFN-γ Activation on the Dynamics of iNOS Gene Expression in LPS Stimulated Macrophages.

PubMed

Salim, Taha; Sershen, Cheryl L; May, Elebeoba E

2016-01-01

Macrophage produced inducible nitric oxide synthase (iNOS) is known to play a critical role in the proinflammatory response against intracellular pathogens by promoting the generation of bactericidal reactive nitrogen species. Robust and timely production of nitric oxide (NO) by iNOS and analogous production of reactive oxygen species are critical components of an effective immune response. In addition to pathogen associated lipopolysaccharides (LPS), iNOS gene expression is dependent on numerous proinflammatory cytokines in the cellular microenvironment of the macrophage, two of which include interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α). To understand the synergistic effect of IFN-γ and TNF-α activation, and LPS stimulation on iNOS expression dynamics and NO production, we developed a systems biology based mathematical model. Using our model, we investigated the impact of pre-infection cytokine exposure, or priming, on the system. We explored the essentiality of IFN-γ priming to the robustness of initial proinflammatory response with respect to the ability of macrophages to produce reactive species needed for pathogen clearance. Results from our theoretical studies indicated that IFN-γ and subsequent activation of IRF1 are essential in consequential production of iNOS upon LPS stimulation. We showed that IFN-γ priming at low concentrations greatly increases the effector response of macrophages against intracellular pathogens. Ultimately the model demonstrated that although TNF-α contributed towards a more rapid response time, measured as time to reach maximum iNOS production, IFN-γ stimulation was significantly more significant in terms of the maximum expression of iNOS and the concentration of NO produced.

Comparison of Human and Rhesus Macaque T-Cell Responses Elicited by Boosting with NYVAC Encoding Human Immunodeficiency Virus Type 1 Clade C Immunogens▿

PubMed Central

Mooij, Petra; Balla-Jhagjhoorsingh, Sunita S.; Beenhakker, Niels; van Haaften, Patricia; Baak, Ilona; Nieuwenhuis, Ivonne G.; Heidari, Shirin; Wolf, Hans; Frachette, Marie-Joelle; Bieler, Kurt; Sheppard, Neil; Harari, Alexandre; Bart, Pierre-Alexandre; Liljeström, Peter; Wagner, Ralf; Pantaleo, Giuseppe; Heeney, Jonathan L.

2009-01-01

Rhesus macaques (Macaca mulatta) have played a valuable role in the development of human immunodeficiency virus (HIV) vaccine candidates prior to human clinical trials. However, changes and/or improvements in immunogen quality in the good manufacturing practice (GMP) process or changes in adjuvants, schedule, route, dose, or readouts have compromised the direct comparison of T-cell responses between species. Here we report a comparative study in which T-cell responses from humans and macaques to HIV type 1 antigens (Gag, Pol, Nef, and Env) were induced by the same vaccine batches prepared under GMP and administered according to the same schedules in the absence and presence of priming. Priming with DNA (humans and macaques) or alphavirus (macaques) and boosting with NYVAC induced robust and broad antigen-specific responses, with highly similar Env-specific gamma interferon (IFN-γ) enzyme-linked immunospot assay responses in rhesus monkeys and human volunteers. Persistent cytokine responses of antigen-specific CD4+ and CD8+ T cells of the central memory as well as the effector memory phenotype, capable of simultaneously eliciting multiple cytokines (IFN-γ, interleukin 2, and tumor necrosis factor alpha), were induced. Responses were highly similar in humans and primates, confirming earlier data indicating that priming is essential for inducing robust NYVAC-boosted IFN-γ T-cell responses. While significant similarities were observed in Env-specific responses in both species, differences were also observed with respect to responses to other HIV antigens. Future studies with other vaccines using identical lots, immunization schedules, and readouts will establish a broader data set of species similarities and differences with which increased confidence in predicting human responses may be achieved. PMID:19321612

Arthritis is inhibited in Borrelia-primed and infected interleukin-17A-deficient mice after administration of anti-gamma-interferon, anti-tumor necrosis factor alpha and anti-interleukin-6 antibodies.

PubMed

Kuo, Joseph; Warner, Thomas F; Schell, Ronald F

2017-08-31

The role that cytokines play in the induction of Lyme arthritis is gradually being delineated. We showed previously that severe arthritis developed in a T-cell-driven murine model, even in mice lacking interleukin-17A (IL-17A) and administered anti-gamma-interferon (IFN-γ) antibody. Increased levels of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), two pro-inflammatory cytokines, were detected in cultures of popliteal lymph node cells obtained from these mice. We hypothesized that concomitantly administered anti-IL-6, anti-TNF-α and anti-IFN-γ antibodies would inhibit the development of arthritis in IL-17A-deficient mice. Our results showed that swelling of the hind paws and histopathological changes consistent with arthritis were significantly reduced in IL-17A-deficient mice that administered the three anti-cytokine antibodies. These results suggest that treatment with multiple anti-cytokine antibodies can abrogate the induction of Lyme arthritis in mice. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Studying radiolytic ageing of nuclear power plant electric cables with FTIR spectroscopy.

PubMed

Levet, A; Colombani, J; Duponchel, L

2017-09-01

Due to the willingness to extend the nuclear power plants length of life, it is of prime importance to understand long term ageing effect on all constitutive materials. For this purpose gamma-irradiation effects on insulation of instrumentation and control cables are studied. Mid-infrared spectroscopy and principal components analysis (PCA) were used to highlight molecular modifications induced by gamma-irradiation under oxidizing conditions. In order to be closer to real world conditions, a low dose rate of 11Gyh -1 was used to irradiate insulations in full cable or alone with a dose up to 58 kGy. Spectral differences according to irradiation dose were extracted using PCA. It was then possible to observe different behaviors of the insulation constitutive compounds i.e. ethylene vinyl acetate (EVA), ethylene propylene diene monomer (EPDM) and aluminium trihydrate (ATH). Irradiation of insulations led to the oxidation of their constitutive polymers and a modification of filler-polymer ratio. Moreover all these modifications were observed for insulations alone or in full cable indicating that oxygen easily diffuses into the material. Spectral contributions were discussed considering different degradation mechanisms. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of a CD44/CD122int memory CD8 T cell subset generated under sterile inflammatory conditions.

PubMed

Mbitikon-Kobo, Florentin-Martial; Vocanson, Marc; Michallet, Marie-Cécile; Tomkowiak, Martine; Cottalorda, Anne; Angelov, Georgi S; Coupet, Charles-Antoine; Djebali, Sophia; Marçais, Antoine; Dubois, Bertrand; Bonnefoy-Bérard, Nathalie; Nicolas, Jean-François; Arpin, Christophe; Marvel, Jacqueline

2009-03-15

Most memory CD8 T cell subsets that have been hitherto defined are generated in response to infectious pathogens. In this study, we have characterized the CD8 T cells that survive priming conditions, devoid of pathogen-derived danger signals. In both a TCR-transgenic model and a model of contact hypersensitivity, we show that the priming of naive CD8 T cells under sterile inflammatory conditions generates memory. The corresponding memory CD8 T cells can be identified by their intermediate expression levels of CD44 and CD122. We also show that CD44/122(int) memory CD8 T cells spontaneously develop in wild type mice and that they display intermediate levels of several other memory traits including functional (IFN-gamma secretion capacity, CCL5 messenger stores), phenotypic, and molecular (T-bet and eomesodermin expression levels) features. We finally show that they correspond to an early differentiation stage and can further differentiate in CD44/122(high) memory T cells. Altogether, our results identify a new memory CD8 T cell subset that is generated under sterile inflammatory conditions and involved in the recall contact hypersensitivity reactions that are responsible for allergic contact dermatitis.

Transfer of in vitro expanded T lymphocytes after activation with dendritomas prolonged survival of mice challenged with EL4 tumor cells.

PubMed

Li, Jinhua; Theofanous, Leigh; Stickel, Sara; Bouton-Verville, Hilary; Burgin, Kelly E; Jakubchak, Susan; Wagner, Thomas E; Wei, Yanzhang

2007-07-01

Adoptive T cell transfer after in vitro expansion represents an attractive cancer immunotherapy. The majority of studies so far have been focusing on the expansion of tumor infiltrated lymphocytes (TIL) and some have shown very encouraging results. Recently, we have developed a unique tumor immune response activator, dendritomas, by fusion of dendritic cells and tumor cells. Animal studies and early clinical trials have shown that dendritomas are able to activate tumor specific immune responses. In this study, we hypothesized that naïve T cells can be primed with dendritomas and expanded in vitro to develop an adoptive transfer therapy for patients who do not have solid tumors, such as leukemia. T cells were isolated and purified from lymph nodes of mice. The cells were then incubated with dendritomas made from syngeneic DCs and tumor cells and expanded in vitro using Dynabeads mouse CD3/CD28 T cell expander for approximately three weeks. The in vitro primed and expanded T cells showed tumor cell specific CTL activity and increased secretion of IFN-gamma. Tumor bearing mice receiving the in vitro expanded T cells survived significantly longer than control mice. Furthermore, the depletion of regulator T cells enhanced the survival of the mice that received the adoptive transfer therapy.

Interleukin-12 (IL-12)-driven alloimmune responses in vitro and in vivo: requirement for beta1 subunit of the IL-12 receptor.

PubMed

Piccotti, J R; Li, K; Chan, S Y; Eichwald, E J; Bishop, D K

1999-06-15

Interleukin-12 (IL-12) mediates its biologic activities via binding high-affinity receptors on T and natural killer cells. Although emphasis has been placed on the requirement for IL-12Rbeta2 in IL-12 bioactivity, the role of IL-12Rbeta1 is less well defined. The current study evaluated the effects of exogenous IL-12 on alloantigen-specific immune responses and determined the requirement for IL-12Rbeta1 in IL-12-mediated alloimmunity. The mouse heterotopic cardiac transplant model was employed to evaluate the effects of IL-12 on alloantigen-specific immune responses in vivo. In addition, IFN-gamma production in mixed lymphocyte cultures (MLC) supplemented with IL-12 was measured to assess the effects of IL-12 on Th1 function in vitro. Mice deficient in IL-12Rbeta1 (IL-12Rbeta1-/-) were used to determine the requirement for this receptor component in IL-12-driven alloimmune responses. Addition of IL-12 to MLC consisting of wild-type splenocytes enhanced alloantigen-specific proliferative responses and Th1 development. In contrast, IL-12 did not alter these in vitro immune parameters in IL-12Rbeta1-/- MLC. Treatment of wild-type cardiac allograft recipients with IL-12 resulted in high concentrations of serum interferon-gamma (IFN-gamma) and a 10-fold increase in IFN-gamma production by recipient splenocytes after restimulation in vitro. However, this fulminate Th1 response did not accelerate allograft rejection. Importantly, IL-12 had no effect on serum IFN-gamma or in vivo priming of Thl in IL-12Rbeta1-/- recipients. Finally, administration of IL-12 to WT allograft recipients resulted in a bimodal alloantibody response: antibody production was suppressed at high doses of IL-12, and enhanced at lower doses. IL-12 markedly enhances alloantigen-specific immune function; however, these exaggerated Th1-driven responses do not culminate in accelerated allograft rejection. Further, these data indicate that IL-12Rbeta1 is essential for the enhancement of both in vitro and in vivo alloimmune responses by exogenous IL-12.

Smoking Gun Found for Gamma-Ray Burst in Milky Way

NASA Astrophysics Data System (ADS)

2004-06-01

Combined data from NASA's Chandra X-ray Observatory and infrared observations with the Palomar 200-inch telescope have uncovered evidence that a gamma-ray burst, one of nature's most catastrophic explosions, occurred in our Galaxy a few thousand years ago. The supernova remnant, W49B, may also be the first remnant of a gamma-ray burst discovered in the Milky Way. W49B is a barrel-shaped nebula located about 35,000 light years from Earth. The new data reveal bright infrared rings, like hoops around a barrel, and intense X-radiation from iron and nickel along the axis of the barrel. "These results provide intriguing evidence that an extremely massive star exploded in two powerful, oppositely directed jets that were rich in iron," said Jonathan Keohane of NASA's Jet Propulsion Laboratory at a press conference at the American Astronomical Society meeting in Denver. "This makes W49B a prime candidate for being the remnant of a gamma ray burst involving a black hole collapsar." "The nearest known gamma-ray burst to Earth is several million light years away - most are billions of light years distant - so the detection of the remnant of one in our galaxy would be a major breakthrough," said William Reach, one of Keohane's collaborators from the California Institute of Technology. According to the collapsar theory, gamma-ray bursts are produced when a massive star runs out of nuclear fuel and the star's core collapses to form a black hole surrounded by a disk of extremely hot, rapidly rotating, magnetized gas. Much of this gas is pulled into the black hole, but some is flung away in oppositely directed jets of gas traveling at near the speed of light. An observer aligned with one these jets would see a gamma-ray burst, a blinding flash in which the concentrated power equals that of ten quadrillion Suns for a minute or so. The view perpendicular to the jets is a less astonishing, although nonetheless spectacular supernova explosion. For W49B, the jet is tilted out of the plane of the sky by about 20 degrees. W49B Chandra Fe K-line Image of W49B Four rings about 25 light years in diameter can be identified in the infrared image. These rings, which are due to warm gas, were presumably flung out by the rapid rotation of the massive star a few hundred thousand years before the star exploded. The rings were pushed outward by a hot wind from the star a few thousand years before it exploded. Chandra's image and spectral data show that the jets of multimillion-degree-Celsius gas extending along the axis of the barrel are rich in iron and nickel ions, consistent with their being ejected from the center of the star. This distinguishes the explosion from a conventional type II supernova in which most of the Fe and Ni goes into making the neutron star, and the outer part of the star is what is flung out. In contrast, in the collapsar model of gamma ray bursts iron and nickel from the center is ejected along the jet. At the ends of the barrel, the X-ray emission flares out to make a hot cap. The X-ray cap is surrounded by a flattened cloud of hydrogen molecules detected in the infrared. These features indicate that the shock wave produced by the explosion has encountered a large, dense cloud of gas and dust. The scenario that emerges is one in which a massive star formed from a dense cloud of dust, shone brightly for a few million years while spinning off rings of gas and pushing them away, forming a nearly empty cavity around the star. The star then underwent a collapsar-type supernova explosion that resulted in a gamma-ray burst. The observations of W49B may help to resolve a problem that has bedeviled the collapsar model for gamma-ray bursts. On the one hand, the model is based on the collapse of a massive star, which is normally formed from a dense cloud. On the other hand, observations of the afterglow of many gamma-ray bursts indicate that the explosion occurred in a low-density gas. Based on the W49B data, the resolution proposed by Keohane and colleagues is that the star had carved out an extensive low-density cavity in which the explosion subsequently occurred. "This star appears to have exploded inside a bubble it had created," said Keohane. "In a sense, it dug its own grave." NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the Office of Space Science, NASA Headquarters, Washington. Northrop Grumman of Redondo Beach, Calif., formerly TRW, Inc., was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. The image and additional information are available at: http://chandra.harvard.edu and http://chandra.nasa.gov

Map of Martian Polar Hydrogen

NASA Technical Reports Server (NTRS)

2003-01-01

This gamma ray spectrometer map centered on the north pole of Mars is based on gamma-rays from the element hydrogen. In this region, hydrogen is mainly in the form of water ice. Regions of high ice content are shown in red and those low in ice content are shown in blue. The very ice-rich region at the north pole is due to a permanent polar cap of water ice on the surface. Elsewhere in this region, the ice is buried under several to a few tens of centimeters of dry soil. The sub-surface ice is not uniformly distributed in the north, but varies with both latitude and longitude. In the north, the soil is well over 50 percent ice, which is more than can be accommodated by just filling the pore space in pre-existing soil. This high ice content implies that the ice may have been slowly co-deposited with dust in the past when conditions were wetter. Deposition of ice by this process means it is more likely that the ice deposits are very thick and may even be deep enough to have liquid water at their base.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The gamma ray spectrometer was provided by the University of Arizona, Tucson. Lockheed Martin Astronautics, Denver, Colo., is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Distinct CD4+-T-cell responses to live and heat-inactivated Aspergillus fumigatus conidia.

PubMed

Rivera, Amariliz; Van Epps, Heather L; Hohl, Tobias M; Rizzuto, Gabrielle; Pamer, Eric G

2005-11-01

Aspergillus fumigatus is an important fungal pathogen that causes invasive pulmonary disease in immunocompromised hosts. Respiratory exposure to A. fumigatus spores also causes allergic bronchopulmonary aspergillosis, a Th2 CD4+-T-cell-mediated disease that accompanies asthma. The microbial factors that influence the differentiation of A. fumigatus-specific CD4+ T lymphocytes into Th1 versus Th2 cells remain incompletely defined. We therefore examined CD4+-T-cell responses of immunologically intact mice to intratracheal challenge with live or heat-inactivated A. fumigatus spores. Live but not heat-inactivated fungal spores resulted in recruitment of gamma interferon (IFN-gamma)-producing, fungus-specific CD4+ T cells to lung airways, achieving A. fumigatus-specific frequencies exceeding 5% of total CD4+ T cells. While heat-inactivated spores did not induce detectable levels of IFN-gamma-producing, A. fumigatus-specific CD4+ T cells in the airways, they did prime CD4+ T-cell responses in draining lymph nodes that produced greater amounts of interleukin 4 (IL-4) and IL-13 than T cells responding to live conidia. While immunization with live fungal spores induced antibody responses, we found a marked decrease in isotype-switched, A. fumigatus-specific antibodies in sera of mice following immunization with heat-inactivated spores. Our studies demonstrate that robust Th1 T-cell and humoral responses are restricted to challenge with fungal spores that have the potential to germinate and cause invasive infection. How the adaptive immune system distinguishes between metabolically active and inactive fungal spores remains an important question.

Effect of diffusional creep on particle morphology of polycrystalline alloys strengthened by second phase particles

NASA Technical Reports Server (NTRS)

Wittenberger, J. D.; Behrendt, D. R.

1973-01-01

Diffusional creep in a polycrystalline alloy containing second-phase particles can disrupt the particle morphology. For alloys which depend on the particle distribution for strength, changes in the particle morphology can affect the mechanical properties. Recent observations of diffusional creep in alloys containing soluble particles (gamma-prime strengthened Ni base alloys) and inert particles have been reexamined in light of the basic mechanisms of diffusional creep, and a generalized model of this effect is proposed. The model indicates that diffusional creep will generally result in particle-free regions in the vicinity of grain boundaries serving as net vacancy sources. The factors which control the changes in second-phase morphology have been identified, and methods of reducing the effects of diffusional creep are suggested.

Pilot Study: Unique Response of Bone Tissue During an Investigation of Radio-Adaptive Effects in Mice

NASA Technical Reports Server (NTRS)

Sibonga, J. D.; Iwaniec, U.; Wu, H.

2011-01-01

PURPOSE: We obtained bone tissue to evaluate the collateral effects of experiments designed to investigate molecular mechanisms of radio-adaptation in a mouse model. Radio-adaptation describes a process by which the prior exposure to low dose radiation can protect against the toxic effect of a subsequent high dose exposure. In the radio-adaptation experiments, C57Bl/6 mice were exposed to either a Sham or a priming Low Dose (5 cGy) of Cs-137 gamma rays before being exposed to either a Sham or High Dose (6 Gy) 24 hours later. ANALYSIS: Bone tissue were obtained from two experiments where mice were sacrificed at 3 days (n=3/group, 12 total) and at 14 days (n=6/group, 24 total) following high dose exposure. Tissues were analyzed to 1) evaluate a radio-adaptive response in bone tissue and 2) describe cellular and microstructural effects for two skeletal sites with different rates of bone turnover. One tibia and one lumbar vertebrae (LV2), collected at the 3-day time-point, were analyzed by bone histomorphometry and micro-CT to evaluate the cellular response and any evidence of microarchitectural impact. Likewise, tibia and LV2, collected at the 14-day time-point, were analyzed by micro-CT alone to evaluate resulting changes to bone structure and microarchitecture. The data were analyzed by 2-way ANOVA to evaluate the effects of the priming low dose radiation, of the high dose radiation, and of any interaction between the priming low and high doses of radiation. Bone histomorphometry was performed in the cancellous bone (aka trabecular bone) compartments of the proximal tibial metaphysis and of LV2. RESULTS: Cellular Response @ 3 Days The priming Low Dose radiation decreased osteoblast-covered bone perimeter in the proximal tibia and the total cell density in the bone marrow in the LV2. High Dose radiation, regardless of prior exposure to priming dose, dramatically reduced total cell density in bone marrow of both the long bone and vertebra. However, in the proximal tibia, High Dose radiation increased the osteoclast-covered bone perimeters, the density of adipocytes in bone marrow, and the area of bone marrow occupied by fat cells -- while in the LV2, adipocytes were rare and not stimulated by High Dose radiation. In an unexpected response, High Dose radiation dramatically increased (10-fold) osteoblast-covered bone perimeter in the LV2.

The Alveolar Microenvironment of Patients Infected with Human Immunodeficiency Virus Does Not Modify Alveolar Macrophage Interactions with Streptococcus pneumoniae

PubMed Central

Jagoe, R. Thomas; Jarman, Elizabeth R.; North, James C.; Pridmore, Alison; Musaya, Janelisa; French, Neil; Zijlstra, Eduard E.; Molyneux, Malcolm E.; Read, Robert C.

2013-01-01

We tested the hypothesis that HIV infection results in activation of alveolar macrophages and that this might be associated with impaired defense against pneumococcus. We compared alveolar macrophages and lymphocytes in 131 bronchoalveolar lavage samples from HIV-infected and healthy controls using inflammatory gene microarrays, flow cytometry, real-time PCR, and enzyme-linked immunosorbent assay (ELISA) to determine the pattern of macrophage activation associated with HIV infection and the effect of this activation on defense against pneumococcus. We used gamma interferon (IFN-γ) priming to mimic the cellular milieu in HIV-infected lungs. InnateDB and BioLayout 3D were used to analyze the interactions of the upregulated genes. Alveolar macrophages from HIV-infected adults showed increased gene expression and cytokine production in a classical pattern. Bronchoalveolar lavage from HIV-infected subjects showed excess CD8+ lymphocytes with activated phenotype. Toll-like receptor 4 (TLR4) expression was increased in macrophages from HIV-infected subjects, but function was similar between the groups; lung lavage fluid did not inhibit TLR function in transfected HeLa cells. Alveolar macrophages from HIV-infected subjects showed normal binding and internalization of opsonized pneumococci, with or without IFN-γ priming. Alveolar macrophages from HIV-infected subjects showed classical activation compared to that of healthy controls, but this does not alter macrophage interactions with pneumococci. PMID:23576675

Synthesis of the new compound CaFe(CO 3) 2 and experimental constraints on the (Ca,Fe)CO 3 join

NASA Astrophysics Data System (ADS)

Davidson, Paula M.; Symmes, Gregory H.; Cohen, Barbara A.; Reeder, Richard J.; Lindsley, Donald H.

1993-12-01

Synthesis of the new (disordered) compound CaFe(CO 3) 2 has been achieved with the use of Fe-substituted CaCO 3(Cc ss) + Ca-substituted FeCO 3(Sid ss) as starting materials, and high CO 2 pressures. High pressure (20-30 kbar) is needed to stabilize FeCO 3 to sufficiently high temperatures for disordered CaFe(CO 3) 2 to form. Experiments provide reversed compositions of coexisting disordered phases in the CaFe join and locate the solvus temperature for CaFe(C) 3) 2 between 815 and 845°C at 30 kbars. Calculated phase relations predict that the stability of ordered CaFe(CO 3) 2 is limited to T < ˜450°C by the breakdown to Cc ss + Sid ss. A comparison of the unit-cell volume measured for disordered CaFe(CO 3) 2 vs. that estimated for ordered CaFe(CO 3) 2 suggests that increasing pressure stabilizes the disordered phase.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kejun, Z.; Zhanpeng, J.

There are three intermetallic compounds in the Ni{sub 3}Nb, Ni{sub 6}Nb{sub 7}, and Ni{sub 8}Nb. Several attempts have been made to describe the Ni-Nb phase diagram by means of a thermodynamic approach. Kaufman and Nesor modeled the intermetallic compounds as line compounds. The compound Ni{sub 6}Nb{sub 7} was predicted to melt congruently, contrary to experimental data. In the work of Chevalier the homogeneity ranges of the compound phases were not considered, and the calculated (Ni) solvus overestimated the solubility of Nb. Although Ni{sub 6}Nb{sub 7} phase was described with a sublattice model, its nonzero width has not been predicted. Thismore » paper reports that a stoichiometric phase can usually be regarded as composed of two or more sublattices, the sites of each one being occupied by a certain element. If the phase has a small range of homogeneity, different species, which are sufficiently similar in size, shape, electronegativity, etc., may form mixtures on several of the sublattices.« less

Experimentally determined compositions of diopside-jadeite pyroxene in equilibrium with albite and quartz at 1200-1350°C and 15-34 kbar

NASA Astrophysics Data System (ADS)

Gasparik, Tibor

1985-03-01

Equilibrium compositions of diopside-jadeite pyroxene coexisting with albite and quartz were experimentally determined at 25 different P-T conditions, using an electron microprobe for analysis. The new data and the 600°C data of HOLLAND (1983) provided the following mixing properties of the diopside (Di)-jadeite (Jd) solid solution (J, K): Gxs = XJdXDi[12600 - 9.45 T + (12600 - 7.6 T)( XJd - XDi) - (21400 - 16.2 T)( XJd - XDi) 2]. The Di-Jd solution is close to ideal above 1000°C but immiscible below 565°C. The Di-Jd solvus is slightly asymmetric with the crest at composition Di 42.4Jd 57.6. Excess enthalpy is positive but smaller than indicated by the enthalpy of solution measurements of WOODet al. (1980). Disorder in the Di-Jd solution is significantly smaller than complete disorder implied by the ionic two-site model.

Inactivation of the ribonucleoside triphosphate reductase from Lactobacillus leichmannii by 2 prime -chloro-2 prime -deoxyuridine 5 prime -triphosphate: A 3 prime -2 prime hydrogen transfer during the formation of 3 prime -keto-2 prime -deoxyuridine 5 prime -triphosphate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ashley, G.W.; Harris, G.; Stubbe, J.

1988-10-04

The ribonucleoside triphosphate reductase of Lactobacillus leichmannii converts the substrate analogue 2{prime}-chloro-2{prime}-deoxyuridine 5{prime}-triphosphate (C1UTP) into a mixture of 2{prime}-deoxyuridine triphosphate (dUTP) and the unstable product 3{prime}-keto-2{prime}-deoxyuridine triphosphate (3{prime}-keto-dUTP). This ketone can be trapped by reduction with NaBH{sub 4}, producing a 4:1 mixture of xylo-dUTP and dUTP. When (3{prime}-{sup 3}H)C1UTP is treated with enzyme in the presence of NaBH{sub 4}, the isomeric deoxyuridines isolated after alkaline phosphatase treatment retained 15% of the {sup 3}H in C1UTP. Degradation of these isomeric nucleosides has established the location of the {sup 3}H in 3{prime}-keto-dUTP as predominantly 2{prime}(S). The xylo-dU had 98.6% of its labelmore » at the 2{prime}(S) position and 1.5% at 2{prime}(R). The isolated dU had 89.6% of its label at 2{prime}(S) and 1.4% at 2{prime}(R), with the remaining 9% label inferred to be at the 3{prime}-carbon, this resulting from the direct enzymic production of dUTP. These results are consistent with enzymic production of a 1:1,000 mixture of dUTP and 3{prime}-keto-dUTP, where the 3{prime}-hydrogen of C1UTP is retained at 3{prime} during production of dUTP and is transferred to 2{prime}(S) during production of 3{prime}-keto-dUTP. The implications of these results and the unique role of the cofactor adenosylcobalamin are discussed in terms of reductase being a model for the B{sub 12}-dependent rearrangement reactions.« less

Associative and repetition priming with the repeated masked prime technique: no priming found.

PubMed

Avons, S E; Russo, Riccardo; Cinel, Caterina; Verolini, Veronica; Glynn, Kevin; McDonald, Rebecca; Cameron, Marie

2009-01-01

Wentura and Frings (2005) reported evidence of subliminal categorical priming on a lexical decision task, using a new method of visual masking in which the prime string consisted of the prime word flanked by random consonants and random letter masks alternated with the prime string on successive refresh cycles. We investigated associative and repetition priming on lexical decision, using the same method of visual masking. Three experiments failed to show any evidence of associative priming, (1) when the prime string was fixed at 10 characters (three to six flanking letters) and (2) when the number of flanking letters were reduced or absent. In all cases, prime detection was at chance level. Strong associative priming was observed with visible unmasked primes, but the addition of flanking letters restricted priming even though prime detection was still high. With repetition priming, no priming effects were found with the repeated masked technique, and prime detection was poor but just above chance levels. We conclude that with repeated masked primes, there is effective visual masking but that associative priming and repetition priming do not occur with experiment-unique prime-target pairs. Explanations for this apparent discrepancy across priming paradigms are discussed. The priming stimuli and prime-target pairs used in this study may be downloaded as supplemental materials from mc.psychonomic-journals.org/content/supplemental.

Cognate status and cross-script translation priming.

PubMed

Voga, Madeleine; Grainger, Jonathan

2007-07-01

Greek-French bilinguals were tested in three masked priming experiments with Greek primes and French targets. Related primes were the translation equivalents of target words, morphologically related to targets, or phonologically related to targets. In Experiment 1, cognate translation equivalents (phonologically similar translations) showed facilitatory priming, relative to matched phonologically related primes, in conditions in which morphologically related primes showed no effect (50-msec prime exposure). Cross-language morphological priming emerged at longer prime exposure durations (66 msec), but cognate primes continued to generate more priming than did those in the morphological condition. In Experiments 2 and 3, the level of phonological overlap across translation equivalents was varied, and priming effects were measured against those for matched phonologically related primes and those in an unrelated prime condition. When measured against the unrelated baseline, cognate primes showed the typical advantage over noncognate primes. However, this cognate advantage disappeared when priming was measured against the phonologically related prime condition. The results are discussed in terms of how translation equivalents are represented in bilingual memory.

Selective induction of cell-mediated immunity and protection of rhesus macaques from chronic SHIV{sub KU2} infection by prophylactic vaccination with a conserved HIV-1 envelope peptide-cocktail

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nehete, Pramod N.; Nehete, Bharti P.; Hill, Lori

2008-01-05

Infection of Indian-origin rhesus macaques by the simian human immunodeficiency virus (SHIV) is considered to be a suitable preclinical model for directly testing efficacy of vaccine candidates based on the HIV-1 envelope. We used this model for prophylactic vaccination with a peptide-cocktail comprised of highly conserved HIV-1 envelope sequences immunogenic/antigenic in macaques and humans. Separate groups of macaques were immunized with the peptide-cocktail by intravenous and subcutaneous routes using autologous dendritic cells (DC) and Freund's adjuvant, respectively. The vaccine elicited antigen specific IFN-{gamma}-producing cells and T-cell proliferation, but not HIV-neutralizing antibodies. The vaccinated animals also exhibited efficient cross-clade cytolytic activitymore » against target cells expressing envelope proteins corresponding to HIV-1 strains representative of multiple clades that increased after intravenous challenge with pathogenic SHIV{sub KU2}. Virus-neutralizing antibodies were either undetectable or present only transiently at low levels in the control as well as vaccinated monkeys after infection. Significant control of plasma viremia leading to undetectable levels was achieved in majority of vaccinated monkeys compared to mock-vaccinated controls. Monkeys vaccinated with the peptide-cocktail using autologous DC, compared to Freund's adjuvant, and the mock-vaccinated animals, showed significantly higher IFN-{gamma} production, higher levels of vaccine-specific IFN-{gamma} producing CD4{sup +} cells and significant control of plasma viremia. These results support DC-based vaccine delivery and the utility of the conserved HIV-1 envelope peptide-cocktail, capable of priming strong cell-mediated immunity, for potential inclusion in HIV vaccination strategies.« less

Technology of High-speed Direct Laser Deposition from Ni-based Superalloys

NASA Astrophysics Data System (ADS)

Klimova-Korsmik, Olga; Turichin, Gleb; Zemlyakov, Evgeniy; Babkin, Konstantin; Petrovsky, Pavel; Travyanov, Andrey

Recently, additive manufacturing is the one of most perspective technologies; it can replace conventional methods of casting and subsequent time-consuming machining. One of the most interesting additive technologies - high-speed direct laser deposition (HSDLD) allows realizing heterophase process during the manufacturing, which there is process takes place with a partial melting of powder. This is particularly important for materials, which are sensitive to strong fluctuations of temperature treatment regimes, like nickel base alloys with high content of gamma prime phase. This alloys are interested for many industrial areas, mostly there are used in engine systems, aircraft and shipbuilding, aeronautics. Heating and cooling rates during the producing process determine structure and affect on its properties. Using HSDLD process it possible to make a products from Ni superalloys with ultrafine microstructure and satisfactory mechanical characteristics without special subsequent heatreatment.

Anisotropy of high temperature strength in precipitation-hardened nickel-base superalloy single crystals

NASA Technical Reports Server (NTRS)

Nakagawa, Y. G.; Terashima, H.; Yoshizawa, H.; Ohta, Y.; Murakami, K.

1986-01-01

The anisotropy of high temperature strength of nickel-base superalloy, Alloy 454, in service for advanced jet engine turbine blades and vanes, was investigated. Crystallographic orientation dependence of tensile yield strength, creep and creep rupture strength was found to be marked at about 760C. In comparison with other single crystal data, a larger allowance in high strength off-axial orientation from the 001 axis, and relatively poor strength at near the -111 axis were noted. From transmission electron microscopy the anisotropic characteristics of this alloy were explained in terms of available slip systems and stacking geometries of gamma-prime precipitate cuboids which are well hardened by a large tantalum content. 100 cube slip was considered to be primarily responsible for the poor strength of the -111 axis orientation replacing the conventional 111 plane slip systems.

Method for heat treating iron-nickel-chromium alloy

DOEpatents

Merrick, Howard F.; Korenko, Michael K.

1982-01-01

A method for heat treating an age-hardenable iron-nickel-chromium alloy to obtain a bimodal distribution of gamma prime phase within a network of dislocations, the alloy consisting essentially of about 25% to 45% nickel, 10% to 16% chromium, 1.5% to 3% of an element selected from the group consisting of molybdenum and niobium, about 2% titanium, about 3% aluminum, and the remainder substantially all iron. To obtain optimum results, the alloy is heated to a temperature of 1025.degree. C. to 1075.degree. C. for 2-5 minutes, cold-worked about 20% to 60%, aged at a temperature of about 775.degree. C. for 8 hours followed by an air-cool, and then heated to a temperature in the range of 650.degree. C. to 700.degree. C. for 2 hours followed by an air-cool.

Recrystallization characteristics of oxide dispersion strengthened nickel-base alloys

NASA Technical Reports Server (NTRS)

Hotzler, R. K.; Glasgow, T. K.

1980-01-01

Electron microscopy was employed to study the process of recrystallization in two oxide dispersion strengthened (ODS) mechanically alloyed nickel-base alloys, MA 754 and MA 6000E. MA 754 contained both fine, uniformly dispersed particles and coarser oxides aligned along the working direction. Hot rolled MA 754 had a grain size of 0.5 microns and high dislocation densities. After partial primary recrystallization, the fine grains transformed to large elongated grains via secondary (or abnormal) grain growth. Extruded and rolled MA 6000E contained equiaxed grains of 0.2 micron diameter. Primary recrystallization occurring during working eliminated virtually all dislocations. Conversion from fine to coarse grains was triggered by gamma prime dissolution; this was also a process of secondary or abnormal grain growth. Comparisons were made to conventional and oxide dispersion strengthened nickel-base alloys.

Radioadaptive Cytoprotective Pathways in the Mouse Retina

NASA Technical Reports Server (NTRS)

Zanello, Susana B.; Wotring, V.; Theriot, C.; Ploutz-Snyder, R.; Zhang, Y.; Wu, H.

2010-01-01

Exposure to cosmic radiation implies a risk of tissue degeneration. Radiation retinopathy is a complication of radiotherapy and exhibits common features with other retinopathies and neuropathies. Exposure to a low radiation dose elicits protective cellular events (radioadaptive response), reducing the stress of a subsequent higher dose. To assess the risk of radiation-induced retinal changes and the extent to which a small priming dose reduces this risk, we used a mouse model exposed to a source of Cs-137-gamma radiation. Gene expression profiling of retinas from non-irradiated control C57BL/6J mice (C) were compared to retinas from mice treated with a low 50 mGy dose (LD), a high 6 Gy dose (HD), and a combined treatment of 50 mGy (priming) and 6 Gy (challenge) doses (LHD). Whole retina RNA was isolated and expression analysis for selected genes performed by RTqPCR. Relevant target genes associated with cell death/survival, oxidative stress, cellular stress response and inflammation pathways, were analyzed. Cellular stress response genes were upregulated at 4 hr after the challenge dose in LHD retinas (Sirt1: 1.5 fold, Hsf1: 1.7 fold, Hspa1a: 2.5 fold; Hif1a: 1.8 fold, Bag1: 1.7). A similar trend was observed in LD animals. Most antioxidant enzymes (Hmox1, Sod2, Prdx1, Cygb, Cat1) and inflammatory mediators (NF B, Ptgs2 and Tgfb1) were upregulated in LHD and LD retinas. Expression of the pro-survival gene Bcl2 was upregulated in LD (6-fold) and LHD (4-fold) retinas. In conclusion, cytoprotective gene networks activation in the retina suggests a radioadaptive response to a priming irradiation dose, with mitigation of the deleterious effects of a subsequent high dose exposure. The enhancement of these cytoprotective mechanisms has potential value as a countermeasure to ocular alterations caused by radiation alone or in combination with other factors in spaceflight environments.

A novel multi-antigen virally vectored vaccine against Mycobacterium avium subspecies paratuberculosis.

PubMed

Bull, Tim J; Gilbert, Sarah C; Sridhar, Saranya; Linedale, Richard; Dierkes, Nicola; Sidi-Boumedine, Karim; Hermon-Taylor, John

2007-11-28

Mycobacterium avium subspecies paratuberculosis causes systemic infection and chronic intestinal inflammation in many species including primates. Humans are exposed through milk and from sources of environmental contamination. Hitherto, the only vaccines available against Mycobacterium avium subspecies paratuberculosis have been limited to veterinary use and comprised attenuated or killed organisms. We developed a vaccine comprising a fusion construct designated HAV, containing components of two secreted and two cell surface Mycobacterium avium subspecies paratuberculosis proteins. HAV was transformed into DNA, human Adenovirus 5 (Ad5) and Modified Vaccinia Ankara (MVA) delivery vectors. Full length expression of the predicted 95 kDa fusion protein was confirmed. Vaccination of naïve and Mycobacterium avium subspecies paratuberculosis infected C57BL/6 mice using DNA-prime/MVA-boost or Ad5-prime/MVA-boost protocols was highly immunogenic resulting in significant IFN-gamma ELISPOT responses by splenocytes against recombinant vaccine antigens and a range of HAV specific peptides. This included strong recognition of a T-cell epitope GFAEINPIA located near the C-terminus of the fusion protein. Antibody responses to recombinant vaccine antigens and HAV specific peptides but not GFAEINPIA, also occurred. No immune recognition of vaccine antigens occurred in any sham vaccinated Mycobacterium avium subspecies paratuberculosis infected mice. Vaccination using either protocol significantly attenuated pre-existing Mycobacterium avium subspecies paratuberculosis infection measured by qPCR in spleen and liver and the Ad5-prime/MVA-boost protocol also conferred some protection against subsequent challenge. No adverse effects of vaccination occurred in any of the mice. A range of modern veterinary and clinical vaccines for the treatment and prevention of disease caused by Mycobacterium avium subspecies paratuberculosis are needed. The present vaccine proved to be highly immunogenic without adverse effect in mice and both attenuated pre-existing Mycobacterium avium subspecies paratuberculosis infection and conferred protection against subsequent challenge. Further studies of the present vaccine in naturally infected animals and humans are indicated.

Immunization of Pigs by DNA Prime and Recombinant Vaccinia Virus Boost To Identify and Rank African Swine Fever Virus Immunogenic and Protective Proteins

PubMed Central

2018-01-01

ABSTRACT African swine fever virus (ASFV) causes an acute hemorrhagic fever in domestic pigs, with high socioeconomic impact. No vaccine is available, limiting options for control. Although live attenuated ASFV can induce up to 100% protection against lethal challenge, little is known of the antigens which induce this protective response. To identify additional ASFV immunogenic and potentially protective antigens, we cloned 47 viral genes in individual plasmids for gene vaccination and in recombinant vaccinia viruses. These antigens were selected to include proteins with different functions and timing of expression. Pools of up to 22 antigens were delivered by DNA prime and recombinant vaccinia virus boost to groups of pigs. Responses of immune lymphocytes from pigs to individual recombinant proteins and to ASFV were measured by interferon gamma enzyme-linked immunosorbent spot (ELISpot) assays to identify a subset of the antigens that consistently induced the highest responses. All 47 antigens were then delivered to pigs by DNA prime and recombinant vaccinia virus boost, and pigs were challenged with a lethal dose of ASFV isolate Georgia 2007/1. Although pigs developed clinical and pathological signs consistent with acute ASFV, viral genome levels were significantly reduced in blood and several lymph tissues in those pigs immunized with vectors expressing ASFV antigens compared with the levels in control pigs. IMPORTANCE The lack of a vaccine limits the options to control African swine fever. Advances have been made in the development of genetically modified live attenuated ASFV that can induce protection against challenge. However, there may be safety issues relating to the use of these in the field. There is little information about ASFV antigens that can induce a protective immune response against challenge. We carried out a large screen of 30% of ASFV antigens by delivering individual genes in different pools to pigs by DNA immunization prime and recombinant vaccinia virus boost. The responses in immunized pigs to these individual antigens were compared to identify the most immunogenic. Lethal challenge of pigs immunized with a pool of antigens resulted in reduced levels of virus in blood and lymph tissues compared to those in pigs immunized with control vectors. Novel immunogenic ASFV proteins have been identified for further testing as vaccine candidates. PMID:29386289

Immunization of Pigs by DNA Prime and Recombinant Vaccinia Virus Boost To Identify and Rank African Swine Fever Virus Immunogenic and Protective Proteins.

PubMed

Jancovich, James K; Chapman, Dave; Hansen, Debra T; Robida, Mark D; Loskutov, Andrey; Craciunescu, Felicia; Borovkov, Alex; Kibler, Karen; Goatley, Lynnette; King, Katherine; Netherton, Christopher L; Taylor, Geraldine; Jacobs, Bertram; Sykes, Kathryn; Dixon, Linda K

2018-04-15

African swine fever virus (ASFV) causes an acute hemorrhagic fever in domestic pigs, with high socioeconomic impact. No vaccine is available, limiting options for control. Although live attenuated ASFV can induce up to 100% protection against lethal challenge, little is known of the antigens which induce this protective response. To identify additional ASFV immunogenic and potentially protective antigens, we cloned 47 viral genes in individual plasmids for gene vaccination and in recombinant vaccinia viruses. These antigens were selected to include proteins with different functions and timing of expression. Pools of up to 22 antigens were delivered by DNA prime and recombinant vaccinia virus boost to groups of pigs. Responses of immune lymphocytes from pigs to individual recombinant proteins and to ASFV were measured by interferon gamma enzyme-linked immunosorbent spot (ELISpot) assays to identify a subset of the antigens that consistently induced the highest responses. All 47 antigens were then delivered to pigs by DNA prime and recombinant vaccinia virus boost, and pigs were challenged with a lethal dose of ASFV isolate Georgia 2007/1. Although pigs developed clinical and pathological signs consistent with acute ASFV, viral genome levels were significantly reduced in blood and several lymph tissues in those pigs immunized with vectors expressing ASFV antigens compared with the levels in control pigs. IMPORTANCE The lack of a vaccine limits the options to control African swine fever. Advances have been made in the development of genetically modified live attenuated ASFV that can induce protection against challenge. However, there may be safety issues relating to the use of these in the field. There is little information about ASFV antigens that can induce a protective immune response against challenge. We carried out a large screen of 30% of ASFV antigens by delivering individual genes in different pools to pigs by DNA immunization prime and recombinant vaccinia virus boost. The responses in immunized pigs to these individual antigens were compared to identify the most immunogenic. Lethal challenge of pigs immunized with a pool of antigens resulted in reduced levels of virus in blood and lymph tissues compared to those in pigs immunized with control vectors. Novel immunogenic ASFV proteins have been identified for further testing as vaccine candidates. Copyright © 2018 Jancovich et al.

Inverse target- and cue-priming effects of masked stimuli.

PubMed

Mattler, Uwe

2007-02-01

The processing of a visual target that follows a briefly presented prime stimulus can be facilitated if prime and target stimuli are similar. In contrast to these positive priming effects, inverse priming effects (or negative compatibility effects) have been found when a mask follows prime stimuli before the target stimulus is presented: Responses are facilitated after dissimilar primes. Previous studies on inverse priming effects examined target-priming effects, which arise when the prime and the target stimuli share features that are critical for the response decision. In contrast, 3 experiments of the present study demonstrate inverse priming effects in a nonmotor cue-priming paradigm. Inverse cue-priming effects exhibited time courses comparable to inverse target-priming effects. Results suggest that inverse priming effects do not arise from specific processes of the response system but follow from operations that are more general.

Oligomerizations of deoxyadenosine bis-phosphates and of their 3-prime-5-prime, 3-prime-3-prime, and 5-prime-5-prime dimers - Effects of a pyrophosphate-linked, poly(T) analog

NASA Technical Reports Server (NTRS)

Visscher, J.; Bakker, C. G.; Schwartz, Alan W.

1990-01-01

The effect of a 3-prime-5-prime pyrophosphate-linked oligomer of pTp on oligomerizations of pdAp and of its 3-prime-5-prime, 3-prime-3-prime, and 5-prime-5-prime dimers was investigated, using HPLC to separate the reaction mixtures; peak detection was by absorbance monitoring at 254 nm. It was expected that the dimers would form stable complexes with the template, with the degree of stability depending upon the internal linkage of each dimer. It was found that, although the isomers differ substantially in their oligomerization behavior in the absence of template, the analog-template catalyzes the oligomerization to about the same extent in all three cases.

A task-difficulty artifact in subliminal priming.

PubMed

Pratte, Michael S; Rouder, Jeffrey N

2009-08-01

Subliminal priming is said to occur when a subliminal prime influences the classification of a subsequent target. Most subliminal-priming claims are based on separate target- and prime-classification tasks. Because primes are intended to be subliminal, the prime-classification task is difficult, and the target-classification task is easy. To assess whether this task-difficulty difference accounts for previous claims of subliminal priming, we manipulated the ease of the prime-classification task by intermixing long-duration (visible) primes with short-duration (near liminal) ones. In Experiment 1, this strategy of intermixing long-duration primes raised classification of the short-duration ones. In Experiments 2 and 3, prime duration was lowered in such a way that prime classification was at chance in intermixed presentations. Under these conditions, we failed to observe any priming effects; hence, previous demonstrations of subliminal priming may simply have reflected a task-difficulty artifact.

Masked priming effect reflects evidence accumulated by the prime.

PubMed

Kinoshita, Sachiko; Norris, Dennis

2010-01-01

In the same-different match task, masked priming is observed with the same responses but not different responses. Norris and Kinoshita's (2008) Bayesian reader account of masked priming explains this pattern based on the same principle as that explaining the absence of priming for nonwords in the lexical decision task. The pattern of priming follows from the way the model makes optimal decisions in the two tasks; priming does not depend on first activating the prime and then the target. An alternative explanation is in terms of a bias towards responding "same" that exactly counters the facilitatory effect of lexical access. The present study tested these two views by varying both the degree to which the prime predicts the response and the visibility of the prime. Unmasked primes produced effects expected from the view that priming is influenced by the degree to which the prime predicts the response. In contrast, with masked primes, the size of priming for the same response was completely unaffected by predictability. These results rule out response bias as an explanation of the absence of masked priming for different responses and, in turn, indicate that masked priming is not a consequence of automatic lexical access of the prime.

Repetition priming effects from attended vs. ignored single words in a semantic categorization task.

PubMed

Ortells, Juan J; Fox, Elaine; Noguera, Carmen; Abad, María J F

2003-10-01

The present research examines priming effects from a centrally presented single-prime word to which participants were instructed to either attend or ignore. The prime word was followed by a single central target word to which participants made a semantic categorization (animate vs. inanimate) task. The main variables manipulated across experiments were attentional instructions (attend vs. ignore the prime word), presentation duration of the prime word (20, 50, 80 or 100 ms), prime-target stimulus onset asynchrony (SOA; 300 vs. 800 ms), and temporal presentation of instructions (before vs. after the prime word). The results showed (a) a consistent interaction between attentional instructions and repetition priming and (b) a qualitatively different ignored priming pattern as a function of prime duration: reduced positive priming (relative to the attend instruction) for prime exposures of 80 and 100 ms, and reliable negative priming for the shorter prime exposures of 20 and 50 ms. In addition (c), the differential priming pattern for attend and ignore trials was observed at a prime-target SOA of 800 ms (but not at a shorter 300-ms SOA) and only when instructions were presented before the prime word. Methodological and theoretical implications of the present findings for the extant negative priming literature are discussed.

Early dynamics of the semantic priming shift

PubMed Central

Lavigne, Frédéric; Chanquoy, Lucile; Dumercy, Laurent; Vitu, Françoise

2013-01-01

Semantic processing of sequences of words requires the cognitive system to keep several word meanings simultaneously activated in working memory with limited capacity. The real- time updating of the sequence of word meanings relies on dynamic changes in the associates to the words that are activated. Protocols involving two sequential primes report a semantic priming shift from larger priming of associates to the first prime to larger priming of associates to the second prime, in a range of long SOAs (stimulus-onset asynchronies) between the second prime and the target. However, the possibility for an early semantic priming shift is still to be tested, and its dynamics as a function of association strength remain unknown. Three multiple priming experiments are proposed that cross-manipulate association strength between each of two successive primes and a target, for different values of short SOAs and prime durations. Results show an early priming shift ranging from priming of associates to the first prime only to priming of strong associates to the first prime and all of the associates to the second prime. We investigated the neural basis of the early priming shift by using a network model of spike frequency adaptive cortical neurons (e.g., Deco & Rolls, 2005), able to code different association strengths between the primes and the target. The cortical network model provides a description of the early dynamics of the priming shift in terms of pro-active and retro-active interferences within populations of excitatory neurons regulated by fast and unselective inhibitory feedback. PMID:23717346

Priming mortality salience: supraliminal, subliminal and "double-death" priming techniques.

PubMed

Mahoney, Melissa B; Saunders, Benjamin A; Cain, Nicole M

2014-01-01

The study examined whether successively presented subliminal and supraliminal morality salience primes ("double death" prime) would have a stronger influence on death thought accessibility than subliminal or supraliminal primes alone. A between-subjects 2 (subliminal prime/control) × 2 (supraliminal prime/control) design was used. The supraliminal prime prompted participants to answer questions about death. For the subliminal prime, the word death was presented outside of awareness. Both priming techniques differed significantly from a control in ability to elicit mortality salience. There was an interactive influence of both primes. Implications for unconscious neutral networks relating to death are discussed.

Subliminal priming with nearly perfect performance in the prime-classification task.

PubMed

Finkbeiner, Matthew

2011-05-01

The subliminal priming paradigm is widely used by cognitive scientists, and claims of subliminal perception are common nowadays. Nevertheless, there are still those who remain skeptical. In a recent critique of subliminal priming, Pratte and Rouder (Attention, Perception, & Psychophysics, 71, 1276-1283, 2009) suggested that previous claims of subliminal priming may have been due to a failure to control the task difficulty between the experiment proper and the prime-classification task. Essentially, because the prime-classification task is more difficult than the experiment proper, the prime-classification task results may underrepresent the subjects' true ability to perceive the prime stimuli. To address this possibility, prime words were here presented in color. In the experiment proper, priming was observed. In the prime-classification task, subjects reported the color of the primes very accurately, indicating almost perfect control of task difficulty, but they could not identify the primes. Thus, I conclude that controlling for task difficulty does not eliminate subliminal priming.

Leading, but not trailing, primes influence temporal order perception: further evidence for an attentional account of perceptual latency priming.

PubMed

Scharlau, Ingrid

2002-11-01

Presenting a masked prime leading a target influences the perceived onset of the masking target (perceptual latency priming; Scharlau & Neumann, in press). This priming effect is explained by the asynchronous updating model (Neumann, 1982; Scharlau & Neumann, in press): The prime initiates attentional allocation toward its location, which renders a trailing target at the same place consciously available earlier. In three experiments, this perceptual latency priming by leading primes was examined jointly with the effects of trailing primes in order to compare the explanation of the asynchronous updating model with the onset-averaging and the P-center hypotheses. Experiment 1 showed that an attended, as well as an unattended, prime leads to perceptual latency priming. In addition, a large effect of trailing primes on the onset of a target was found. As Experiment 2 demonstrated, this effect is quite robust, although smaller than that of a leading prime. In Experiment 3, masked primes were used. Under these conditions, no influence of trailing primes could be found, whereas perceptual latency priming persisted. Thus, a nonattentional explanation for the effect of trailing primes seems likely.

Phonological and Orthographic Overlap Effects in Fast and Masked Priming

PubMed Central

Frisson, Steven; Bélanger, Nathalie N.; Rayner, Keith

2014-01-01

We investigated how orthographic and phonological information is activated during reading, using a fast priming task, and during single word recognition, using masked priming. Specifically, different types of overlap between prime and target were contrasted: high orthographic and high phonological overlap (track-crack), high orthographic and low phonological overlap (bear-gear), or low orthographic and high phonological overlap (fruit-chute). In addition, we examined whether (orthographic) beginning overlap (swoop-swoon) yielded the same priming pattern as end (rhyme) overlap (track-crack). Prime durations were 32 and 50ms in the fast priming version, and 50ms in the masked priming version, and mode of presentation (prime and target in lower case) was identical. The fast priming experiment showed facilitatory priming effects when both orthography and phonology overlapped, with no apparent differences between beginning and end overlap pairs. Facilitation was also found when prime and target only overlapped orthographically. In contrast, the masked priming experiment showed inhibition for both types of end overlap pairs (with and without phonological overlap), and no difference for begin overlap items. When prime and target only shared principally phonological information, facilitation was only found with a long prime duration in the fast priming experiment, while no differences were found in the masked priming version. These contrasting results suggest that fast priming and masked priming do not necessarily tap into the same type of processing. PMID:24365065

DDOTI: the Deca-Degree Optical Transient Imager

NASA Technical Reports Server (NTRS)

Watson, Alan M.; Lee, William H.; Troja, Eleonora; Roman-Zuniga, Carlos G.; Butler, Nathaniel R.; Kutyrev, Alexander S.; Gehrels, Neil A.; Angeles, Fernando; Basa, Stephane; Blanc, Pierre-Eric;

Treatment with bindarit, an inhibitor of MCP-1 synthesis, protects mice against trinitrobenzene sulfonic acid-induced colitis.

PubMed

Bhatia, M; Landolfi, C; Basta, F; Bovi, G; Ramnath, R Devi; de Joannon, A Capezzone; Guglielmotti, A

2008-10-01

Chemokines play a fundamental role in trafficking and activation of leukocytes in colonic inflammation. We investigated the ability of bindarit, an inhibitor of monocyte chemoattractant protein-1 (MCP-1/CCL2) synthesis, to inhibit chemokine production by human intestinal epithelial cells (HT-29) and its effect in trinitro-benzene sulfonic acid (TNBS)-induced colitis in mice. HT-29 cells were incubated with bindarit in the presence of TNF-alpha/IFN-gamma and 24 h later supernatants were collected for MCP-1, IL-8 and RANTES measurement. A 1 mg enema of TNBS was given to BALB/c mice, and bindarit (100 mg/kg) was orally administered twice daily starting from two days before colitis induction. Weight loss, histology, and MCP-1 level and myeloperoxidase (MPO) activity in colon extracts were assessed. In HT-29 cells, bindarit concentration-dependently and selectively inhibited MCP-1 secretion (as well as mRNA expression) primed by TNF-alpha/IFN-gamma. Moreover treatment with bindarit reduced clinical and histopathological severity of TNBS-induced colitis. These effects were associated with significant inhibition of MCP-1 and MPO in colon extracts. Bindarit exhibits a potent bioactivity in reducing leukocyte infiltration, down-regulating MCP-1 synthesis, and preventing the development of severe colitis in a mice model of TNBS-induced colitis. These observations suggest a potential use of MCP-1 synthesis blockers in intestinal inflammation in humans.

Modeling the convective transport of pollutants from eastern Colorado, USA into Rocky Mountain National Park

NASA Astrophysics Data System (ADS)

Pina, A.; Schumacher, R. S.; Denning, S.

2015-12-01

Rocky Mountain National Park (RMNP) is a Class I Airshed designated under the Clean Air Act. Atmospheric nitrogen (N) deposition in the Park has been a known problem since weekly measurements of wet deposition of inorganic N began in the 1980s by the National Atmospheric Deposition Program (NADP). The addition of N from urban and agriculture emissions along the Colorado Front Range to montane ecosystems degrades air quality/visibility, water quality, and soil pH levels. Based on NADP data during summers 1994-2014, wet N deposition at Beaver Meadows in RMNP exhibited a bimodal gamma distribution. In this study, we identified meteorological transport mechanisms for 3 high wet-N deposition events (all events were within the secondary peak of the gamma distribution) using the North American Regional Reanalysis (NARR) and the Weather Research and Forecasting (WRF) model. The NARR was used to identify synoptic-scale influences on the transport; the WRF model was used to analyze the convective transport of pollutants from a concentrated animal feeding operation near Greeley, Colorado, USA. The WRF simulation included a passive tracer from the feeding operation and a convection-permitting horizontal spacing of 4/3 km. The three cases suggest (a) synoptic-scale moisture and flow patterns are important for priming summer transport events and (b) convection plays a vital role in the transport of Front Range pollutants into RMNP.

Coordinate regulation of the mother centriole component nlp by nek2 and plk1 protein kinases.

PubMed

Rapley, Joseph; Baxter, Joanne E; Blot, Joelle; Wattam, Samantha L; Casenghi, Martina; Meraldi, Patrick; Nigg, Erich A; Fry, Andrew M

2005-02-01

Mitotic entry requires a major reorganization of the microtubule cytoskeleton. Nlp, a centrosomal protein that binds gamma-tubulin, is a G(2)/M target of the Plk1 protein kinase. Here, we show that human Nlp and its Xenopus homologue, X-Nlp, are also phosphorylated by the cell cycle-regulated Nek2 kinase. X-Nlp is a 213-kDa mother centriole-specific protein, implicating it in microtubule anchoring. Although constant in abundance throughout the cell cycle, it is displaced from centrosomes upon mitotic entry. Overexpression of active Nek2 or Plk1 causes premature displacement of Nlp from interphase centrosomes. Active Nek2 is also capable of phosphorylating and displacing a mutant form of Nlp that lacks Plk1 phosphorylation sites. Importantly, kinase-inactive Nek2 interferes with Plk1-induced displacement of Nlp from interphase centrosomes and displacement of endogenous Nlp from mitotic spindle poles, while active Nek2 stimulates Plk1 phosphorylation of Nlp in vitro. Unlike Plk1, Nek2 does not prevent association of Nlp with gamma-tubulin. Together, these results provide the first example of a protein involved in microtubule organization that is coordinately regulated at the G(2)/M transition by two centrosomal kinases. We also propose that phosphorylation by Nek2 may prime Nlp for phosphorylation by Plk1.

Pb(B{sup {prime}}{sub 1/2}B{sup {prime}{prime}}{sub 1/2})O{sub 3}-type perovskites: Part II. Short-range order parameter as a criterion of the distinction between relaxor and normal ferroelectrics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, S.; Jang, H.M.

1997-08-01

A classification scheme of Pb(B{sup {prime}}{sub 1/2}B{sup {prime}{prime}}{sub 1/2})O{sub 3}-type perovskites with respect to the B-site order parameters was proposed based on the theoretical calculation of the short-range order parameter ({sigma}) using the pair-correlation model. The calculated order parameters predict that a Pb(B{sup {prime}}{sub 1/2}B{sup {prime}{prime}}{sub 1/2})O{sub 3}-type perovskite without any charge difference between B{sup {prime}} and B{sup {prime}{prime}} cations [e.g., Pb(Zr{sub 1/2}Ti{sub 1/2})O{sub 3} (PZT)] is represented by a completely disordered state with the absence of a finite coherence length. On the other hand, a Pb(B{sup {prime}}{sub 1/2}B{sup {prime}{prime}}{sub 1/2})O{sub 3} type perovskite system having different ionic charges ismore » characterized either by the short-range ordering with a nanoscale coherence length or by the macroscopic long-range ordering, depending on the magnitude of ionic charge difference between B{sup {prime}} and B{sup {prime}{prime}} ions. The normal ferroelectricity in Pb(B{sup {prime}}{sub 1/2}B{sup {prime}{prime}}{sub 1/2})O{sub 3}-type complex perovskites was then correlated either with a completely disordered state ({sigma}=0) or with a perfectly ordered state ({sigma}=1), whereas the relaxor behavior was attributed to the nanoscale short-range ordering (0{lt}{sigma}{lt}1) in the configuration of the B-site cations. {copyright} {ital 1997 Materials Research Society.}« less

Understanding the Role of the ‘Self’ in the Social Priming of Mimicry

PubMed Central

Wang, Yin; Hamilton, Antonia F de C

2013-01-01

People have a tendency to unconsciously mimic other's actions. This mimicry has been regarded as a prosocial response which increases social affiliation. Previous research on social priming of mimicry demonstrated an assimilative relationship between mimicry and prosociality of the primed construct: prosocial primes elicit stronger mimicry whereas antisocial primes decrease mimicry. The present research extends these findings by showing that assimilative and contrasting prime-to-behavior effect can both happen on mimicry. Specifically, experiment 1 showed a robust contrast priming effect where priming antisocial behaviors induces stronger mimicry than priming prosocial behaviors. In experiment 2, we manipulated the self-relatedness of the pro/antisocial primes and further revealed that prosocial primes increase mimicry only when the social primes are self-related whereas antisocial primes increase mimicry only when the social primes are self-unrelated. In experiment 3, we used a novel cartoon movie paradigm to prime pro/antisocial behaviors and manipulated the perspective-taking when participants were watching these movies. Again, we found that prosocial primes increase mimicry only when participants took a first-person point of view whereas antisocial primes increase mimicry only when participants took a third-person point of view, which replicated the findings in experiment 2. We suggest that these three studies can be best explained by the active-self theory, which claims that the direction of prime-to-behavior effects depends on how primes are processed in relation to the ‘self’. PMID:23565208

Benefits of rice seed priming are offset permanently by prolonged storage and the storage conditions

PubMed Central

Hussain, Saddam; Zheng, Manman; Khan, Fahad; Khaliq, Abdul; Fahad, Shah; Peng, Shaobing; Huang, Jianliang; Cui, Kehui; Nie, Lixiao

2015-01-01

Seed priming is a commercially successful practice, but reduced longevity of primed seeds during storage may limit its application. We established a series of experiments on rice to test: (1) whether prolonged storage of primed and non-primed rice seeds for 210 days at 25°C or −4°C would alter their viability, (2) how long primed rice seed would potentially remain viable at 25°C storage, and (3) whether or not post-storage treatments (re-priming or heating) would reinstate the viability of stored primed seeds. Two different rice cultivars and three priming agents were used in all experiments. Prolonged storage of primed seeds at 25°C significantly reduced the germination (>90%) and growth attributes (>80%) of rice compared with un-stored primed seeds. However, such negative effects were not observed in primed seeds stored at −4°C. Beneficial effects of seed priming were maintained only for 15 days of storage at 25°C, beyond which the performance of primed seeds was worse even than non-primed seeds. The deteriorative effects of 25°C storage were related with hampered starch metabolism in primed rice seeds. None of the post-storage treatments could reinstate the lost viability of primed seeds suggesting that seeds become unviable by prolonged post-priming storage at 25°C. PMID:25631923

Presentation of human T cell leukemia virus type 1 (HTLV-1) Tax protein by dendritic cells: the underlying mechanism of HTLV-1-associated neuroinflammatory disease.

PubMed

Manuel, Sharrón L; Schell, Todd D; Acheampong, Edward; Rahman, Saifur; Khan, Zafar K; Jain, Pooja

2009-11-01

HTLV-1 is the etiologic agent of a debilitating neurologic disorder, HAM/TSP. This disease features a robust immune response including the oligoclonal expansion of CD8+ CTLs specific for the viral oncoprotein Tax. The key pathogenic process resulting in the proliferation of CTLs and the presentation of Tax peptide remains uncharacterized. We have investigated the role of APCs, particularly DCs, in priming of the anti-Tax CTL response under in vitro and in vivo conditions. We investigated two routes (direct vs. indirect) of Tax presentation using live virus, infected primary CD4+/CD25+ T cells, and the CD4+ T cell line (C8166, a HTLV-1-mutated line that only expresses Tax). Our results indicated that DCs are capable of priming a pronounced Tax-specific CTL response in cell cultures consisting of naïve PBLs as well as in HLA-A*0201 transgenic mice (line HHD II). DCs were able to direct the presentation of Tax successfully through infected T cells, live virus, and cell-free Tax. These observations were comparable with those made with a known stimulant of DC maturation, a combination of CD40L and IFN-gamma. Our studies clearly establish a role for this important immune cell component in HTLV-1 immuno/neuropathogenesis and suggest that modulation of DC functions could be an important tool for therapeutic interventions.

In situ phosphorylation of proteins in MCTs microdissected from rat kidney: Effect of AVP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Homma, S.; Gapstur, S.M.; Yusufi, N.K.

1988-04-01

Adenosine 3{prime},5{prime}-cyclic monophosphate (cAMP)-dependent protein phosphorylation is considered a key step in the cellular action of vasopressin (AVP) to regulate water permeability in collecting tubules. However, the proteins serving as a substrate(s) for phosphorylation in undisrupted cells have not yet been identified. In the present study, the authors developed a method for investigation of in situ phosphorylation of microdissected segments of medullary collecting tubules (MCT) from rat kidney. Incubation of microdissected MCT segments with low concentrations of saponin, semipermeabilization, increased permeability of the membrane for ATP but did not allow leakage of macromolecules such as lactate dehydrogenase. This treatment alsomore » did not cause major disruption of cell structure, or impairment of AVP-sensitive adenylate cyclase. Incubation of semipermeabilized MCT with {gamma}-({sup 32}P)ATP resulted in corporation of {sup 32}P{sub i} into two major protein bands detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis and subsequent autoradiography. Similar incubation of tubules disrupted by hyposmotic solutions and a stronger detergent Triton X-100 resulted in {sup 32}P{sub i} incorporation into multiple protein bands. These findings demonstrate a novel method for identification of endogenous protein substrate(s) for cAMP-dependent protein kinase and other protein kinases and phosphatases that are probably involved in post-cAMP steps in the cellular action of AVP in the intact cells of collecting tubules.« less

Langerhans cells beta 2-adrenoceptors: role in migration, cytokine production, Th priming and contact hypersensitivity.

PubMed

Maestroni, Georges J M; Mazzola, Paola

2003-11-01

We showed that norepinephrine (NE) hampers IL-12 and stimulates IL-10 production via adrenoceptors (ARs) in bone marrow-derived dendritic cells (BMDC) influencing their Th priming ability. Others have shown that Langerhans cells (LC) express mRNA for beta1-, beta2- and alpha1(A)-(ARs) and that catecholamines may inhibit the antigen-presenting capability via beta2-ARs. Here, we show that also BMDC express mRNA for beta1-, beta2-, alpha2(A)- and alpha2(C)-ARs. Inhibition of IL-12 is mediated by both beta2- and alpha2(A)-ARs, while stimulation of IL-10 by beta2-ARs only. In addition, LC migration, the contact hypersensitivity response (CHS) and production of IFN-gamma and IL-2 in draining lymph node cells is increased in mice treated topically with the beta2-AR antagonist ICI 118,551 during FITC sensitization. Activation of beta2-ARs in BMDC before adoptive transfer could reduce both migration and CHS response to FITC. Finally, preincubation of BMDC with LPS in presence of the specific beta2-AR agonist salbutamol impaired their chemotactic response to CCL19 and CCL21 and this effect was neutralized by anti-IL-10 mAb. We suggest that the physiological activation of beta2-ARs in DC (LC) results in stimulation of IL-10 which in turn restrains DC (LC) migration influencing antigen presentation and the consequent CHS response.

The priming function of in-car audio instruction.

PubMed

Keyes, Helen; Whitmore, Antony; Naneva, Stanislava; McDermott, Daragh

2018-05-01

Studies to date have focused on the priming power of visual road signs, but not the priming potential of audio road scene instruction. Here, the relative priming power of visual, audio, and multisensory road scene instructions was assessed. In a lab-based study, participants responded to target road scene turns following visual, audio, or multisensory road turn primes which were congruent or incongruent to the primes in direction, or control primes. All types of instruction (visual, audio, and multisensory) were successful in priming responses to a road scene. Responses to multisensory-primed targets (both audio and visual) were faster than responses to either audio or visual primes alone. Incongruent audio primes did not affect performance negatively in the manner of incongruent visual or multisensory primes. Results suggest that audio instructions have the potential to prime drivers to respond quickly and safely to their road environment. Peak performance will be observed if audio and visual road instruction primes can be timed to co-occur.

The "electrophysiological sandwich": a method for amplifying ERP priming effects.

PubMed

Ktori, Maria; Grainger, Jonathan; Dufau, Stéphane; Holcomb, Phillip J

2012-08-01

We describe the results of a study that combines ERP recordings and sandwich priming, a variant of masked priming that provides a brief preview of the target prior to prime presentation (S. J. Lupker & C. J. Davis, 2009). This has been shown to increase the size of masked priming effects seen in behavioral responses. We found the same increase in sensitivity to ERP priming effects in an orthographic priming experiment manipulating the position of overlap of letters shared by primes and targets. Targets were 6-letter words and primes were formed of the 1st, 3rd, 4th, and 6th letters of targets in the related condition. Primes could be concatenated or hyphenated and could be centered on fixation or displaced by two letter spaces to the left or right. Priming effects with concatenated and/or displaced primes only started to emerge at 250 ms post-target onset, whereas priming effects from centrally located hyphenated primes emerged about 100 ms earlier. Copyright © 2012 Society for Psychophysiological Research.

The “Electrophysiological Sandwich”: A Method for Amplifying ERP Priming Effects

PubMed Central

Ktori, Maria; Grainger, Jonathan; Dufau, Stéphane; Holcomb, Phillip J.

2012-01-01

We describe the results of a study that combines ERP recordings and sandwich priming, a variant of masked priming that provides a brief preview of the target prior to prime presentation (Lupker & Davis, 2009). This has been shown to increase the size of masked priming effects seen in behavioral responses. We found the same increase in sensitivity to ERP priming effects in an orthographic priming experiment manipulating the position of overlap of letters shared by primes and targets. Targets were 6-letter words and primes were formed of the 1st, 3rd, 4th, and 6th letters of targets in the related condition. Primes could be concatenated or hyphenated and could be centered on fixation or displaced by two letter spaces to the left or right. Priming effects with concatenated and/or displaced primes only started to emerge at 250ms post-target onset, whereas priming effects from centrally located hyphenated primes emerged about 100ms earlier. PMID:22681238

Co-occurrence frequency evaluated with large language corpora boosts semantic priming effects.

PubMed

Brunellière, Angèle; Perre, Laetitia; Tran, ThiMai; Bonnotte, Isabelle

2017-09-01

In recent decades, many computational techniques have been developed to analyse the contextual usage of words in large language corpora. The present study examined whether the co-occurrence frequency obtained from large language corpora might boost purely semantic priming effects. Two experiments were conducted: one with conscious semantic priming, the other with subliminal semantic priming. Both experiments contrasted three semantic priming contexts: an unrelated priming context and two related priming contexts with word pairs that are semantically related and that co-occur either frequently or infrequently. In the conscious priming presentation (166-ms stimulus-onset asynchrony, SOA), a semantic priming effect was recorded in both related priming contexts, which was greater with higher co-occurrence frequency. In the subliminal priming presentation (66-ms SOA), no significant priming effect was shown, regardless of the related priming context. These results show that co-occurrence frequency boosts pure semantic priming effects and are discussed with reference to models of semantic network.

Ultrasonic mixing of epoxy curing agents

NASA Technical Reports Server (NTRS)

Hodges, W. T.; St.clair, T. L.

1983-01-01

A new technique for mixing solid curing agents into liquid epoxy resins using ultrasonic energy was developed. This procedure allows standard curing agents such as 4,4 prime-diaminodiphenyl sulfone (4,4 prime-DDS) and its 3,3 prime-isomer, (3,3 prime-DDS) to be mixed without prior melting of the curing agent. It also allows curing agents such as 4,4 prime-diaminodiphenyl sulfone (4,4 prime-DDS) and its 3,3 prime-isomer, (3,3 prime-DDS) to be mixed without prior melting of the curing agent. It also allows curing agents with very high melt temperatures such as 4,4 prime-diaminobenzophenone (4,4 prime-DABP) (242 C) to be mixed without premature curing. Four aromatic diamines were ultrasonically blended into MY-720 epoxy resin. These were 4,4 prime-DDS; 3,3 prime-DDA; 4,4 prime-DABP and 3,3 prime-DABP. Unfilled moldings were cast and cured for each system and their physical and mechanical properties compared.

Oligomerization of deoxynucleoside-biphosphate dimers - Template and linkage specificity

NASA Technical Reports Server (NTRS)

Visscher, J.; Van Der Woerd, R.; Bakker, C. G.; Schwartz, Alan W.

1989-01-01

The oligomerization of the activated 3-prime-5-prime pyrophosphate-linked dimer, pdAppdAp, is presently noted to be selectively favored by a poly(U) template over the 3-prime-3-prime and 5-prime-5-prime linked dimers. Both overall yields and the production of the longest oligomers were markedly stimulated by poly(U)'s presence; in its absence, the 5-prime-5-prime linked dimer became the most reactive, yielding chains of the order of 60 monomer-unit lengths. Remarkable self-organization properties are noted for the 5-prime-5-prime dimer of pdAp.

Treatment of adjuvant arthritis with granulocyte-colony stimulating factor and peptide derived from heat shock protein 65.

PubMed

Brendolan, Andrea; Higuchi, Masanori; Sibley, Richard; Strober, Samuel

2003-01-01

Adjuvant arthritis in Lewis rats is induced by the subcutaneous injection of Mycobacterium tuberculosis in mineral oil, and the predominant T cell immune reactivity is against the heat shock protein 65 derived peptide 176-190. We treated Lewis rats with human recombinant G-CSF followed by (i.v) administration of peptide 176-190 after induction of adjuvant arthritis (AA), and observed decreased disease severity, joint destruction, new bone formation and joint ankylosis. Treatment with G-CSF alone was also effective, but to a lesser extent. In addition, we found that splenocytes from rats treated with G-CSF had reduced antigen presenting capacity compared with splenocytes from vehicle treated rats. Primed lymph node cells from G-CSF plus peptide treated rats showed a marked reduction in proliferation and secretion of IFN-gamma after stimulation with the heat shock protein peptide in vitro as compared to controls.

Effects of recombinant granulocyte-colony stimulating factor administration during Mycobacterium avium infection in mice

PubMed Central

Gonçalves, A S; Appelberg, R

2001-01-01

Granulocyte colony-stimulating factor (G-CSF) administration in vivo has been shown to improve the defence mechanisms against infection by different microbes. Here we evaluated a possible protective role of this molecule in a mouse model of mycobacterial infection. The administration of recombinant G-CSF promoted an extensive blood neutrophilia but failed to improve the course of Mycobacterium avium infection in C57Bl/6 or beige mice. G-CSF administration also failed to improve the efficacy of a triple chemotherapeutic regimen (clarithromycin + ethambutol + rifabutin). G-CSF treatment did not protect interleukin-10 gene disrupted mice infected with M. avium. Spleen cells from infected mice treated with G-CSF had a decreased priming for antigen-specific production of interferon gamma compared to control infected mice. Our data do not substantiate previous reports on the protective activity of G-CSF in antimycobacterial immunity using mouse models. PMID:11422200

An oxide dispersion strengthened Ni-W-Al alloy with superior high temperature strength

NASA Technical Reports Server (NTRS)

Glasgow, T. K.

1976-01-01

An experimental oxide dispersion strengthened (ODS) alloy, WAZ-D, derived from the WAZ-20 composition was produced by the mechanical alloying process. Cast WAZ-20 is strengthened by both a high refractory metal content, and 70 volume percent of gamma prime. The ODS alloy WAZ-D was responsive to variables of alloy content, of attritor processing, of consolidation by extrusion, and of heat treatment. The best material produced had large highly elongated grains. It exhibited tensile strengths generally superior to a comparable cast alloy. The ODS alloy exhibited high temperature stress rupture life considerably superior to any known cast superalloy. Tensile and rupture ductility were low, as was intermediate temperature rupture life. Very low creep rates were noted and some specimens failed with essentially no third stage creep. Also the benefit derived from the oxide dispersion, far out-weighed that from the elongated microstructure alone.

The Effects of Priming on Children's Attitudes toward Older Individuals

ERIC Educational Resources Information Center

Hoe, Sony; Davidson, Denise

2002-01-01

The purpose of the present research was to examine younger (7-years-old) and older (10-years-old) children's attitudes toward older individuals following one type of five primes: positive prime, negative prime, elderly prime, grandparent prime, or neutral prime. Overall, children's attitudes on three tests--Apperception, Semantic Differential, and…

A diffusion model account of masked vs. unmasked priming: Are they qualitatively different?

PubMed Central

Gomez, Pablo; Perea, Manuel; Ratcliff, Roger

2017-01-01

In the past decades, hundreds of articles have explored the mechanisms underlying priming. Most researchers assume that masked and unmasked priming are qualitatively different. For masked priming, the effects are often assumed to reflect savings in the encoding of the target stimulus, whereas for unmasked priming, it has been suggested that the effects reflect the familiarity of the prime-target compound cue. In contrast, other researchers have claimed that masked and unmasked priming reflect essentially the same core processes. In this article, we use the diffusion model (Ratcliff, 1978) to account for the effects of masked and unmasked priming for identity and associatively related primes. The fits of the model lead us to the following conclusion: masked related primes give a head start to the processing of the target compared to unrelated primes, while unmasked priming affects primarily the quality of the lexical information. PMID:23647337

Associative priming effects with visible, transposed-letter nonwords: JUGDE facilitates COURT.

PubMed

Perea, Manuel; Palti, Dafna; Gomez, Pablo

2012-04-01

Associative priming effects can be obtained with masked nonword primes or with masked pseudohomophone primes (e.g., judpe-COURT, tode-FROG), but not with visible primes. The usual explanation is that when the prime is visible, these stimuli no longer activate the semantic representations of their base words. Given the important role of transposed-letter stimuli (e.g., jugde) in visual word recognition, here we examined whether or not an associative priming effect could be obtained with visible transposed-letter nonword primes (e.g., jugde-COURT) in a series of lexical decision experiments. Results showed a sizable associative priming effect with visible transposed-letter nonword primes (i.e., jugde-COURT faster than neevr-COURT) in Experiments 1-3 that was close to that with word primes. In contrast, we failed to find a parallel effect with replacement-letter nonword primes (Experiment 2). These findings pose some constraints to models of visual word recognition.

Prime Diagnosticity in Short-Term Repetition Priming: Is Primed Evidence Discounted, Even when It Reliably Indicates the Correct Answer?

ERIC Educational Resources Information Center

Weidemann, Christoph T.; Huber, David E.; Shiffrin, Richard M.

2008-01-01

The authors conducted 4 repetition priming experiments that manipulated prime duration and prime diagnosticity in a visual forced-choice perceptual identification task. The strength and direction of prime diagnosticity produced marked effects on identification accuracy, but those effects were resistant to subsequent changes of diagnosticity.…

Imide modified epoxy matrix resins

NASA Technical Reports Server (NTRS)

Scola, D. A.

1982-01-01

Results of a program designed to develop tough imide modified epoxy (IME) resins cured by bisimide amine (BIA) hardeners are presented. State of the art epoxy resin, MY720, was used. Three aromatic bisimide amines and one aromatic aliphatic BIA were evaluated. BIA's derived from 6F anhydride (3,3 prime 4,4 prime-(hexafluoro isopropyl idene) bis (phthalic anhydride) and diamines, 3,3 prime-diam nodiphenyl sulfone (3,3 prime-DDS), 4,4 prime-diamino diphenyl sulfone (4,4 prime-DDS), 1.12-dodecane diamine (1,12-DDA) were used. BIA's were abbreviated 6F-3,3 prime-DDS, 6F-4,4 prime-DDS, 6F-3,3 prime-DDS-4,4 prime DDS, and 6F-3,3 prime-DDS-1,12-DDA corresponding to 6F anhydride and diamines mentioned. Epoxy resin and BIA's (MY720/6F-3,3 prime-DDS, MY720/6F-3,3 prime-DDS-4,4 prime-DDS, MY720/6F-3,3 prime-DDS-1,12-DDA and a 50:50 mixture of a BIA and parent diamine, MY720/6F-3,3 prime-DDS/3,3 prime-DDS, MY720/6F-3,3 prime-DDS-4,4 prime-DDS/3,3 prime-DDS, MY720/6F-3,3 prime-DDS-1,12-DDA/3,3 prime-DDS were studied to determine effect of structure and composition. Effect of the addition of two commercial epoxies, glyamine 200 and glyamine 100 on the properties of several formulations was evaluated. Bisimide amine cured epoxies were designated IME's (imide modified epoxy). Physical, thermal and mechanical properties of these resins were determined. Moisture absorption in boiling water exhibited by several of the IME's was considerably lower than the state of the art epoxies (from 3.2% for the control and state of the art to 2.0 wt% moisture absorption). Char yields are increased from 20% for control and state of the art epoxies to 40% for IME resins. Relative toughness characteristics of IME resins were measured by 10 deg off axis tensile tests of Celion 6000/IME composites. Results show that IME's containing 6F-3,3 prime-DDS or 6F-3,3 prime-DDS-1,12-DDA improved the "toughness" characteristics of composites by about 35% (tensile strength), about 35% (intralaminar shear strength), and about 78% (shear strain to failure) relative to the control composite.

The more you ignore me the closer I get: An ERP study of evaluative priming.

PubMed

Gibbons, Henning; Bachmann, Olga; Stahl, Jutta

2014-12-01

We used event-related brain potentials (ERPs) to investigate the various mental processes contributing to evaluative priming-that is, more positive judgments for targets preceded by affectively positive, as opposed to negative, prime stimuli. To ensure ecological validity, we employed a priori meaningful landscape pictures as targets and emotional adjectives as visual primes and presented both primes and targets for relatively long durations (>1 s). Prime-related lateralized readiness potentials (LRPs) revealed response priming as one source of the significant evaluative priming effect. On the other hand, greater right-frontal positive slow wave in the ERP for pictures following negative, as compared with positive, primes indicated altered impression formation, thus supporting automatic spreading activation and/or affect misattribution accounts. Moreover, target LRPs suggested conscious counter-control to reduce the evaluative priming net effect. Finally, when comparing prime ERPs for two groups of participants showing strong versus weak evaluative priming, we found strong evidence for the role of depth of prime processing: In the weak-effect group, prime words evoked an increased visual P1/N1 complex, a larger posterior P2 component, and a greater left-parietal processing negativity presumably reflecting semantic processing. By contrast, a larger medial-frontal P2/N2 complex in the strong-effect group suggested top-down inhibition of the prime's emotional content. Thus, trying to ignore the primes can actually increase, rather than decrease, the evaluative priming effect.

Unconscious response priming during continuous flash suppression

PubMed Central

Grassini, Simone

2018-01-01

Continuous flash suppression (CFS) has become a popular tool for studying unconscious processing, but the level at which unconscious processing of visual stimuli occurs under CFS is not clear. Response priming is a robust and well-understood phenomenon, in which the prime stimulus facilitates overt responses to targets if the prime and target are associated with the same response. We used CFS to study unconscious response priming of shape: arrows with left or right orientation served as primes and targets. The prime was presented near the limen of consciousness and each trial was followed by subjective rating of visibility and a forced-choice response concerning the orientation of the prime in counterbalanced order. In trials without any reported awareness of the presence of the prime, discrimination of the prime’s orientation was at chance level. However, priming was elicited in such unconscious trials. Unconscious priming was not influenced by the prime-target onset-asynchrony (SOA)/prime duration, whereas conscious processing, as indicated by the enhanced discriminability of the prime’s orientation and conscious priming, increased at the longest SOAs/prime durations. These results show that conscious and unconscious processes can be dissociated with CFS and that CFS-masking does not completely suppress unconscious visual processing of shape. PMID:29401503

Collider Signals of a Composite Higgs in the Standard Model with Four Generations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soni, A.; Bar-Shalom, S.; Eilam, G.

2010-03-20

Recent fits of electroweak precision data to the StandardModel (SM) with a 4th sequential family (SM4) point to a possible 'three-prong composite solution': (1) the Higgs mass is at the TeV-scale, (2) the masses of the 4th family quarks t{prime}, b{prime} are of {Omicron}(500) GeV and (3) the mixing angle between the 4th and 3rd generation quarks is of the order of the Cabibbo angle, {theta}{sub 34} {approx} {Omicron}(0.1). Such a manifestation of the SM4 is of particular interest as it may suggest that the Higgs is a composite state, predominantly of the 4th generation heavy quarks. Motivated by themore » above, we show that the three-prong composite solution to the SM4 can have interesting new implications for Higgs phenomenology. For example, the Higgs can decay to a single heavy 4th generation quark via the 3-body decays (through an off-shell t{prime} or b{prime}) H {yields} {bar t}{prime}t{prime}* {yields} {bar t}{prime}bW{sup +} and H {yields} {bar b}{prime}b{prime}* {yields} {bar b}{prime}tW{sup -}. These flavor diagonal decays can be dramatically enhanced at the LHC (by several orders of magnitudes) due to the large width effects of the resonating heavy Higgs in the processes gg {yields} H {yields} {bar t}{prime}t{prime}* {yields} {bar t}{prime}bW{sup +} and gg {yields} H {yields} {bar b}{prime}b{prime}* {yields} {bar b}{prime}tW{sup -}, thus yielding a viable signal above the corresponding continuum QCD production rates. In addition, the Higgs can decay to a single t{prime} and b{prime} in the loop-generated flavor changing (FC) channels H {yields} b{prime}{bar b}, t{prime}{bar t}. These FC decays are essentially 'GIM-free' and can, therefore, have branching ratios as large as 10{sup -4} - 10{sup -3}.« less

Reversed Priming Effects May Be Driven by Misperception Rather than Subliminal Processing.

PubMed

Sand, Anders

2016-01-01

A new paradigm for investigating whether a cognitive process is independent of perception was recently suggested. In the paradigm, primes are shown at an intermediate signal strength that leads to trial-to-trial and inter-individual variability in prime perception. Here, I used this paradigm and an objective measure of perception to assess the influence of prime identification responses on Stroop priming. I found that sensory states producing correct and incorrect prime identification responses were also associated with qualitatively different priming effects. Incorrect prime identification responses were associated with reversed priming effects but in contrast to previous studies, I interpret this to result from the (mis-)perception of primes rather than from a subliminal process. Furthermore, the intermediate signal strength also produced inter-individual variability in prime perception that strongly influenced priming effects: only participants who on average perceived the primes were Stroop primed. I discuss how this new paradigm, with a wide range of d' values, is more appropriate when regression analysis on inter-individual identification performance is used to investigate perception-dependent processing. The results of this study, in line with previous results, suggest that drawing conclusions about subliminal processes based on data averaged over individuals may be unwarranted.

Reversed Priming Effects May Be Driven by Misperception Rather than Subliminal Processing

PubMed Central

Sand, Anders

2016-01-01

A new paradigm for investigating whether a cognitive process is independent of perception was recently suggested. In the paradigm, primes are shown at an intermediate signal strength that leads to trial-to-trial and inter-individual variability in prime perception. Here, I used this paradigm and an objective measure of perception to assess the influence of prime identification responses on Stroop priming. I found that sensory states producing correct and incorrect prime identification responses were also associated with qualitatively different priming effects. Incorrect prime identification responses were associated with reversed priming effects but in contrast to previous studies, I interpret this to result from the (mis-)perception of primes rather than from a subliminal process. Furthermore, the intermediate signal strength also produced inter-individual variability in prime perception that strongly influenced priming effects: only participants who on average perceived the primes were Stroop primed. I discuss how this new paradigm, with a wide range of d′ values, is more appropriate when regression analysis on inter-individual identification performance is used to investigate perception-dependent processing. The results of this study, in line with previous results, suggest that drawing conclusions about subliminal processes based on data averaged over individuals may be unwarranted. PMID:26925016

Motor Priming in Neurorehabilitation

PubMed Central

Stoykov, Mary Ellen; Madhavan, Sangeetha

2014-01-01

Priming is a type of implicit learning wherein a stimulus prompts a change in behavior. Priming has been long studied in the field of psychology. More recently, rehabilitation researchers have studied motor priming as a possible way to facilitate motor learning. For example, priming of the motor cortex is associated with changes in neuroplasticity that are associated with improvements in motor performance. Of the numerous motor priming paradigms under investigation, only a few are practical for the current clinical environment, and the optimal priming modalities for specific clinical presentations are not known. Accordingly, developing an understanding of the various types of motor priming paradigms and their underlying neural mechanisms is an important step for therapists in neurorehabilitation. Most importantly, an understanding of the methods and their underlying mechanisms is essential for optimizing rehabilitation outcomes. The future of neurorehabilitation is likely to include these priming methods, which are delivered prior to or in conjunction with primary neurorehabilitation therapies. In this Special Interest article we discuss those priming paradigms that are supported by the greatest amount of evidence including: (i) stimulation-based priming, (ii) motor imagery and action observation, (iii) sensory priming, (iv) movement-based priming, and (v) pharmacological priming. PMID:25415551

Effects of Religious Priming Concepts on Prosocial Behavior Towards Ingroup and Outgroup.

PubMed

Batara, Jame Bryan L; Franco, Pamela S; Quiachon, Mequia Angelo M; Sembrero, Dianelle Rose M

2016-11-01

Several studies show that there is a connection between religion and prosociality (e.g., Saroglou, 2013). To investigate whether there is a causal relationship between these two variables, a growing number of scholars employed priming religious concepts and measure its influence on prosocial behavior (e.g., Pichon, Boccato, & Saroglou, 2007). In the recent development of religious priming, Ritter and Preston (2013) argued that different primes (agent prime, spiritual/abstract prime, and institutional prime) may also have varying influence on prosocial behavior specifically helping an ingroup or an outgroup target. With this in mind, a 2 (social categorization of the target of help) by 3 (agent prime, institutional prime, spiritual prime) experiment was conducted to directly investigate this hypothesis. Results suggest that priming religious concepts especially the spiritual prime can increase prosocial behaviors. However, no significant effect was found on the social categorization which implies that Filipino participants elicit prosocial behavior regardless of the social categorization (be it ingroup or outgroup) of the target of help. The present study's findings contribute to further the literature on religious priming and its influence on prosocial behavior.

Semantic priming effects from single words in a lexical decision task.

PubMed

Noguera, Carmen; Ortells, Juan J; Abad, María J F; Carmona, Encarnación; Daza, M Teresa

2007-06-01

The present research examines the semantic priming effects of a centrally presented single prime word to which participants were instructed to either "attend and remember" or "ignore". The prime word was followed by a central probe target on which the participants made a lexical decision task. The main variables manipulated across experiments were prime duration (50 or 100 ms), the presence or absence of a mask following the prime, and the presence (or absence) and type of distractor stimulus (random set of consonants or pseudowords) on the probe display. There was a consistent interaction between the instructions and the semantic priming effects. Relative to the "attend and remember" instruction, an "ignore" instruction produced reduced positive priming from single primes presented for 100 ms, irrespective of the presence or absence of a prime mask, and regardless of whether the probe target was presented with or without distractors. Additionally, reliable negative priming was found from ignored primes presented for briefer durations (50 ms) and immediately followed by a mask. Methodological and theoretical implications of the present findings for the extant negative priming literature are discussed.

Interaction of prime and target in the subliminal affective priming effect.

PubMed

Haneda, Kaoruko; Nomura, Michio; Iidaka, Tetsuya; Ohira, Hideki

2003-04-01

It has been found that an emotional stimulus such as a facial expression presented subliminally can affect subsequent information processing and behavior, usually by shifting evaluation of a subsequent stimulus to a valence congruent with the previous stimulus. This phenomenon is called subliminal affective priming. The present study was conducted to replicate and expand previous findings by investigating interaction of primes and targets in the affective priming effect. Two conditions were used. Prime (subliminal presentation 35 msec.) of an angry face of a woman and a No Prime control condition. Just after presentation of the prime, an ambiguous angry face or an emotionally neutral face was presented above the threshold of awareness (500 msec.). 12 female undergraduate women judged categories of facial expressions (Anger, Neutral, or Happiness) for the target faces. Analysis indicated that the Anger primes significantly facilitated judgment of anger for the ambiguous angry faces; however, the priming effect of the Anger primes was not observed for neutral faces. Consequently, the present finding suggested that a subliminal affective priming effect should be more prominent when affective valence of primes and targets is congruent.

Centre-surround inhibition is a general aspect of famous-person recognition: evidence from negative semantic priming from clearly visible primes.

PubMed

Stone, Anna

2012-05-01

A centre-surround attentional mechanism was proposed by Carr and Dagenbach (Journal of Experimental Psychology: Learning, Memory, and Cognition 16: 341-350, 1990) to account for their observations of negative semantic priming from hard-to-perceive primes. Their mechanism cannot account for the observation of negative semantic priming when primes are clearly visible. Three experiments (Ns = 30, 46, and 30) used a familiarity decision with names of famous people, preceded by a prime name with the same occupation as the target or with a different occupation. Negative semantic priming was observed at a 150- or 200-ms SOA, with positive priming at shorter (50-ms) and longer (1,000-ms) SOAs. In Experiment 3, we verified that the primes were easily recognisable in the priming task at an SOA that yielded negative semantic priming, which cannot be predicted by the original centre-surround mechanism. A modified version is proposed that explains transiently negative semantic priming by proposing that centre-surround inhibition is a normal, automatically invoked aspect of the semantic processing of visually presented famous names.

Mechanistic studies of ribonucleoside triphosphate reductase from Lactobacillus leichmannii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, G.M.

1984-01-01

The mechanism of action of the adenosylcobalamin (AdoCbl)-dependent ribonucleoside triphosphate reductase (RTPR) was investigated using isotope effect and substrate specificity studies. These experiments were conducted on RTPR purified by a new method from Lactobacillus leichmannii. Isotope effect studies using (3{prime}-{sup 3}H)UTP and (3{prime}-{sup 3}H)ATP demonstrated that the 3{prime} C-H bond of the nucleotide is cleaved in order to cleave the 2{prime} C-OH bond. AdoCbl does not act as a direct H abstractor from the 3{prime} position of the substrate, but instead is thought to act as a radical chain initiator to generate an amino acid radical on the enzyme. Furthermore » support for this enzyme mediated cleavage of the 3{prime} C-H bond of the nucleotide and the novel role of AdoCbl came from studies using (3{prime}{sup 3}H)2{prime}-chloro-2{prime}-deoxyuridine 5{prime}-triphosphate ((3{prime}-{sup 3}H)CIUTP). Evidence is presented that during the course of this reaction, the {sup 3}H abstracted from the 3{prime} position of (3{prime}-{sup 3}H)CIUTP was either exchanged with the solvent or returned to the {beta} face of the 2{prime} position to produce (2{prime}{sup 3}H)-2{prime}-deoxy-3{prime}-ketoUTP. This result demonstrates that RTPR is capable of catalyzing a rearrangement reaction. The significance of the RTPR-catalyzed rearrangement with respect to the AdoCbl-dependent enzymes which catalyze rearrangements is discussed.« less

Automatic response activation in sequential affective priming: an ERP study

PubMed Central

Leuthold, Hartmut; Rothermund, Klaus; Schweinberger, Stefan R.

2012-01-01

Affective priming effects denote faster responses when two successively presented affective stimuli match in valence than when they mismatch. Two mechanisms have been proposed for their explanation: (i) Priming of affective information within a semantic network or distributed memory system (semantic priming). (ii) Automatic activation of the evaluative response through the affective prime (response priming). In this experiment, we sought more direct evidence for prime-induced response activations with measurement of the lateralized readiness potential (LRP). Onset of the stimulus-locked LRP was earlier in affectively congruent trials than in incongruent trials. In addition, priming modulated the LRP-amplitude of slow responses, indicating greater activation of the incorrect response hand in affectively incongruent trials. Onset of the response-locked LRP and peak latency of the P300 component were not modulated by priming but the amplitude of the N400 component was. In combination, these results suggest that both, semantic priming and response priming constitute affective priming effects in the evaluative categorization task. PMID:21642351

The (un)reliability of item-level semantic priming effects.

PubMed

Heyman, Tom; Bruninx, Anke; Hutchison, Keith A; Storms, Gert

2018-04-05

Many researchers have tried to predict semantic priming effects using a myriad of variables (e.g., prime-target associative strength or co-occurrence frequency). The idea is that relatedness varies across prime-target pairs, which should be reflected in the size of the priming effect (e.g., cat should prime dog more than animal does). However, it is only insightful to predict item-level priming effects if they can be measured reliably. Thus, in the present study we examined the split-half and test-retest reliabilities of item-level priming effects under conditions that should discourage the use of strategies. The resulting priming effects proved extremely unreliable, and reanalyses of three published priming datasets revealed similar cases of low reliability. These results imply that previous attempts to predict semantic priming were unlikely to be successful. However, one study with an unusually large sample size yielded more favorable reliability estimates, suggesting that big data, in terms of items and participants, should be the future for semantic priming research.

Rapid response learning of brand logo priming: Evidence that brand priming is not dominated by rapid response learning.

PubMed

Boehm, Stephan G; Smith, Ciaran; Muench, Niklas; Noble, Kirsty; Atherton, Catherine

2017-08-31

Repetition priming increases the accuracy and speed of responses to repeatedly processed stimuli. Repetition priming can result from two complementary sources: rapid response learning and facilitation within perceptual and conceptual networks. In conceptual classification tasks, rapid response learning dominates priming of object recognition, but it does not dominate priming of person recognition. This suggests that the relative engagement of network facilitation and rapid response learning depends on the stimulus domain. Here, we addressed the importance of the stimulus domain for rapid response learning by investigating priming in another domain, brands. In three experiments, participants performed conceptual decisions for brand logos. Strong priming was present, but it was not dominated by rapid response learning. These findings add further support to the importance of the stimulus domain for the relative importance of network facilitation and rapid response learning, and they indicate that brand priming is more similar to person recognition priming than object recognition priming, perhaps because priming of both brands and persons requires individuation.

A Comparison of Molecular and Histopathological Changes in Mouse Intestinal Tissue Following Whole-Body Proton- or Gamma-Irradiation

NASA Technical Reports Server (NTRS)

Purgason, Ashley; Mangala, Lingegowda; Zhang, Ye; Hamilton, Stanley; Wu, Honglu

2010-01-01

There are many consequences following exposure to the space radiation environment which can adversely affect the health of a crew member. Acute radiation syndrome (ARS) involving nausea and vomiting, damage to radio-sensitive tissue such as the blood forming organs and gastrointestinal tract, and cancer are some of these negative effects. The space radiation environment is ample with protons and contains gamma rays as well. Little knowledge exists to this point, however, regarding the effects of protons on mammalian systems; conversely several studies have been performed observing the effects of gamma rays on different animal models. For the research presented here, we wish to compare our previous work looking at whole-body exposure to protons using a mouse model to our studies of mice experiencing whole-body exposure to gamma rays as part of the radio-adaptive response. Radio-adaptation is a well-documented phenomenon in which cells exposed to a priming low dose of radiation prior to a higher dose display a reduction in endpoints like chromosomal aberrations, cell death, micronucleus formation, and more when compared to their counterparts receiving high dose-irradiation only. Our group has recently completed a radio-adaptive experiment with C57BL/6 mice. For both this study and the preceding proton research, the gastrointestinal tract of each animal was dissected four hours post-irradiation and the isolated small intestinal tissue was fixed in formalin for histopathological examination or snap-frozen in liquid nitrogen for RNA isolation. Histopathologic observation of the tissue using standard H&E staining methods to screen for morphologic changes showed an increase in apoptotic lesions for even the lowest doses of 0.1 Gy of protons and 0.05 Gy of gamma rays, and the percentage of apoptotic cells increased with increasing dose. A smaller percentage of crypts showed 3 or more apoptotic lesions in animals that received 6 Gy of gamma-irradiation compared to mice receiving only 2 Gy of protons. Tissue of the gastrointestinal tract was also homogenized and RNA was isolated for cDNA synthesis and real-time PCR analysis. Inspecting apoptotic lesions of the duodenum of the small intestine as an endpoint of damage did not reveal a radio-adaptive response in C57BL/6 mice at the four hour time point. Results of gene expression changes showed consistent up or down regulation of a number of genes for all of the exposure doses that may play a role in proton-induced apoptosis. Preliminary results of gene expression alterations as a result of gamma-irradiation revealed a wealth of genes involved in oxidative stress and antioxidant defense processes being up- or down-regulated only at the highest exposure dose of 6 Gy and the combined dose of 5 cGy with 6 Gy. Those animals undergoing only 5 cGy of gamma-irradiation showed very little modification of gene expression. Taken together these results lead us to conclude that protons cause more severe morphologic damage to the duodenum of the small intestine at a dose of 2 Gy than a higher dose of 6 Gy of gamma rays to the same organ. Both protons and gamma rays lead to significant variation in gene expression at high doses in the small intestine and these changes may provide insight into the mechanism of injury seen in the gastrointestinal tract following radiation exposure. Astronauts experiencing prolonged exposure to protons in the low Earth orbit and in deep space, and experiencing acute exposure to protons from solar particle events, may face biological consequences that will impact a mission s success. We will continue this work by studying, quantifying, and comparing damage due to protons and gamma rays in the small intestine as well as other organs in a time-dependent manner.

Semantic Priming from Letter-Searched Primes Occurs for Low- but Not High-Frequency Targets: Automatic Semantic Access May Not Be a Myth

ERIC Educational Resources Information Center

Tse, Chi-Shing; Neely, James H.

2007-01-01

Letter-search (LS) within a prime often eliminates semantic priming. In 2 lexical decision experiments, the authors found that priming from LS primes occurred for low-frequency (LF) but not high-frequency (HF) targets whether the target's word frequency was manipulated between or within participants and whether the prime-target pairs were…

Discontinuous precipitation in a Cd-6 at.% Ag alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manna, I.; Bala, P.K.; Pabi, S.K.

1996-11-01

Discontinuous precipitation (DP) in a Cd-6 at.% Ag alloy has been investigated for the first time. The precipitate phase maintains a lamellar morphology and statistically constant interlamellar spacing under a given isothermal condition in the temperature range studied (333--523 K). The interlamellar spacing increases with an increase in isothermal temperature. The reaction front velocity registers a typical C-curve variation with the inverse of temperature. The reaction rate is maximum at 470 K. The predicted upper limit of DP occurrence in this alloy is 23 K lower than the concerned equilibrium solvus temperature. Continuous precipitation accompanies DP at all temperatures, especiallymore » beyond a certain time, and adversely affects the growth kinetics of DP colonies by reducing the local chemical driving force and/or posing physical hindrance to the reaction front migration. An extensive kinetic analysis of DP using the models by Turnbull, Aaronson and Liu, and Petermann and Hornbogen has yielded the grain boundary chemical diffusivity data in Cd-6 At.% Ag for the first time, the activation energy of which lies in the range 55--77 kJ/mol.« less

Effect of Cooling Rates on the Transformation Behavior and Mechanical Properties of a Ni-Rich NiTi Alloy

NASA Astrophysics Data System (ADS)

Coan, Stephen; Shamimi, Ali; Duerig, T. W.

2017-12-01

Slightly nickel-rich Ni-Ti alloys (typically 50.5-51% atomic percent nickel) are commonly used to produce devices that are superelastic at body temperature. This excess nickel can be tolerated in the NiTi matrix when its temperature is above the solvus of about 600 °C, but will precipitate out during lower temperatures. Recent work has been done on exploring the effect lower temperatures have on the material properties of NiTi. Findings showed that properties begin to change at temperatures as low as 100 °C. It is because of these results that it was deemed important to better understand what may be happening during the quenching process itself. Through running a combination of DSC and tensile tests on samples cooled at varying rates, it was found that the cooling rate has an effect on properties when heat treated above a specific temperature. Understanding how quickly the alloy must be cooled to fully retain the supersaturated NiTi matrix is important to optimizing processes and anticipating material properties after a heat treatment.

Laser-induced reversion of δ' precipitates in an Al-Li alloy: Study on temperature rise in pulsed laser atom probe.

PubMed

Khushaim, Muna; Gemma, Ryota; Al-Kassab, Talaat

2016-08-01

The influence of tuning the laser pulse energy during the analyses on the resulting microstructure in a specimen utilizing an ultra-fast laser assisted atom probe was demonstrated by a case study of a binary Al-Li alloy. The decomposition parameters, such as the size, number density, volume fraction, and composition of δ' precipitates, were carefully monitored after each analysis. A simple model was employed to estimate the corresponding specimen temperature for each value of the laser energy. The results indicated that the corresponding temperatures for the laser pulse energy in the range of 10 to 80 pJ are located inside the miscibility gap of the binary Al-Li phase diagram and fall into the metastable equilibrium field. In addition, the corresponding temperature for a laser pulse energy of 100 pJ was in fairly good agreement with reported range of  δ' solvus temperature, suggesting a result of reversion upon heating due to laser pulsing. Microsc. Res. Tech. 79:727-737, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

An experimental system for high temperature X-ray diffraction studies with in situ mechanical loading

PubMed Central

Oswald, Benjamin B.; Schuren, Jay C.; Pagan, Darren C.; Miller, Matthew P.

2013-01-01

An experimental system with in situ thermomechanical loading has been developed to enable high energy synchrotron x-ray diffraction studies of crystalline materials. The system applies and maintains loads of up to 2250 N in uniaxial tension or compression at a frequency of up to 100 Hz. The furnace heats the specimen uniformly up to a maximum temperature of 1200 °C in a variety of atmospheres (oxidizing, inert, reducing) that, combined with in situ mechanical loading, can be used to mimic processing and operating conditions of engineering components. The loaded specimen is reoriented with respect to the incident beam of x-rays using two rotational axes to increase the number of crystal orientations interrogated. The system was used at the Cornell High Energy Synchrotron Source to conduct experiments on single crystal silicon and polycrystalline Low Solvus High Refractory nickel-based superalloy. The data from these experiments provide new insights into how stresses evolve at the crystal scale during thermomechanical loading and complement the development of high-fidelity material models. PMID:23556825

The Role of Representation Strength of the Prime in Subliminal Visuomotor Priming.

PubMed

Wang, Yongchun; Wang, Yonghui; Liu, Peng; Di, Meilin; Gong, Yanyan; Tan, Mengge

2017-11-01

This study investigated the role of representation strength of the prime in subliminal visuomotor priming in two experiments. Prime/target compatibility (compatible and incompatible) and preposed object type (jumbled lines, strong masking; and rectangular outlines, weak masking) were manipulated in Experiment 1. A significant negative compatibility effect (NCE) was observed in the rectangle condition, whereas no compatibility effect was found in the line condition. However, when a new variable, prime duration, was introduced in Experiment 2, the NCE was reversed with an increase in the prime duration in the rectangle condition, whereas the NCE was maintained in the line condition. This result is consistent with the claim that increasing the prime duration causes the prime representation to be too strong for inhibition in the rectangle condition but strong enough to reliably trigger inhibition in the line condition. The findings demonstrated that prime representation has a causal role in subliminal visuomotor priming.

The effects of priming on children's attitudes toward older individuals.

PubMed

Hoe, Sony; Davidson, Denise

2002-01-01

The purpose of the present research was to examine younger (7-years-old) and older (10-years-old) children's attitudes toward older individuals following one type of five primes: positive prime, negative prime, elderly prime, grandparent prime, or neutral prime. Overall, children's attitudes on three tests--Apperception, Semantic Differential, and Attribute Salience--were affected by the type of prime children were given, with positive and grandparent primes resulting in more positive views toward older individuals than negative, elderly, or neutral (control group) primes. The present research provides evidence that priming the most accessible cognitions about an individual can affect even young children's perception of the individual. These results are discussed in terms of category-based and data-driven processing and may explain the disparate findings obtained in previous studies that have shown the children's attitudes toward older individuals are sometimes negative, whereas other studies have shown that children's attitudes are more positive or neutral.

Sequential Stereotype Priming: A Meta-Analysis.

PubMed

Kidder, Ciara K; White, Katherine R; Hinojos, Michelle R; Sandoval, Mayra; Crites, Stephen L

2017-08-01

Psychological interest in stereotype measurement has spanned nearly a century, with researchers adopting implicit measures in the 1980s to complement explicit measures. One of the most frequently used implicit measures of stereotypes is the sequential priming paradigm. The current meta-analysis examines stereotype priming, focusing specifically on this paradigm. To contribute to ongoing discussions regarding methodological rigor in social psychology, one primary goal was to identify methodological moderators of the stereotype priming effect-whether priming is due to a relation between the prime and target stimuli, the prime and target response, participant task, stereotype dimension, stimulus onset asynchrony (SOA), and stimuli type. Data from 39 studies yielded 87 individual effect sizes from 5,497 participants. Analyses revealed that stereotype priming is significantly moderated by the presence of prime-response relations, participant task, stereotype dimension, target stimulus type, SOA, and prime repetition. These results carry both practical and theoretical implications for future research on stereotype priming.

A backwards glance at words: Using reversed-interior masked primes to test models of visual word identification

PubMed Central

Lupker, Stephen J.

2017-01-01

The experiments reported here used “Reversed-Interior” (RI) primes (e.g., cetupmor-COMPUTER) in three different masked priming paradigms in order to test between different models of orthographic coding/visual word recognition. The results of Experiment 1, using a standard masked priming methodology, showed no evidence of priming from RI primes, in contrast to the predictions of the Bayesian Reader and LTRS models. By contrast, Experiment 2, using a sandwich priming methodology, showed significant priming from RI primes, in contrast to the predictions of open bigram models, which predict that there should be no orthographic similarity between these primes and their targets. Similar results were obtained in Experiment 3, using a masked prime same-different task. The results of all three experiments are most consistent with the predictions derived from simulations of the Spatial-coding model. PMID:29244824

Schoolbook Texts: Behavioral Achievement Priming in Math and Language.

PubMed

Engeser, Stefan; Baumann, Nicola; Baum, Ingrid

2016-01-01

Prior research found reliable and considerably strong effects of semantic achievement primes on subsequent performance. In order to simulate a more natural priming condition to better understand the practical relevance of semantic achievement priming effects, running texts of schoolbook excerpts with and without achievement primes were used as priming stimuli. Additionally, we manipulated the achievement context; some subjects received no feedback about their achievement and others received feedback according to a social or individual reference norm. As expected, we found a reliable (albeit small) positive behavioral priming effect of semantic achievement primes on achievement in math (Experiment 1) and language tasks (Experiment 2). Feedback moderated the behavioral priming effect less consistently than we expected. The implication that achievement primes in schoolbooks can foster performance is discussed along with general theoretical implications.

Schoolbook Texts: Behavioral Achievement Priming in Math and Language

PubMed Central

Engeser, Stefan; Baumann, Nicola; Baum, Ingrid

2016-01-01

Prior research found reliable and considerably strong effects of semantic achievement primes on subsequent performance. In order to simulate a more natural priming condition to better understand the practical relevance of semantic achievement priming effects, running texts of schoolbook excerpts with and without achievement primes were used as priming stimuli. Additionally, we manipulated the achievement context; some subjects received no feedback about their achievement and others received feedback according to a social or individual reference norm. As expected, we found a reliable (albeit small) positive behavioral priming effect of semantic achievement primes on achievement in math (Experiment 1) and language tasks (Experiment 2). Feedback moderated the behavioral priming effect less consistently than we expected. The implication that achievement primes in schoolbooks can foster performance is discussed along with general theoretical implications. PMID:26938446

Being forward not backward: lexical limits to masked priming.

PubMed

Davis, Chris; Kim, Jeesun; Forster, Kenneth I

2008-05-01

This study investigated whether masked priming is mediated by existing memory representations by determining whether nonwords targets would show repetition priming. To avoid the potential confound that nonword repetition priming would be obscured by a familiarity response bias, the standard lexical decision and naming tasks were modified to make targets unfamiliar. Participants were required to read a target string from right to left (i.e., "ECAF" should be read as "FACE") and then make a response. To examine if priming was based on lexical representations, repetition primes consisted of words when read forwards or backwards (e.g., "face", "ecaf") and nonwords (e.g., "pame", "emap"). Forward and backward primes were used to test if task instruction affected prime encoding. The lexical decision and naming tasks showed the same pattern of results: priming only occurred for forward primes with word targets (e.g., "face-ECAF"). Additional experiments to test if response priming affected the LDT indicated that the lexical status of the prime per se did not affect target responses. These results showed that the encoding of masked primes was unaffected by the novel task instruction and support the view that masked priming is due to the automatic triggering of pre-established computational processes based on stored information.

Perceptual latency priming by masked and unmasked stimuli: evidence for an attentional interpretation.

PubMed

Scharlau, Ingrid; Neumann, Odmar

2003-08-01

Four experiments investigated the influence of a metacontrast-masked prime on temporal order judgments. The main results were (1) that a masked prime reduced the latency of the mask's conscious perception (perceptual latency priming), (2) that this effect was independent of whether the prime suffered strong or weak masking, (3) that it was unaffected by the degree of visual similarity between the prime and the mask, and that (4) there was no difference between congruent and incongruent primes. Finding (1) suggests that location cueing affects not only response times but also the latency of conscious perception. (2) The finding that priming was unaffected by the prime's detectability argues against a response bias interpretation of this effect. (3) Since visual similarity had no effect on the prime's efficiency, it is unlikely that sensory priming was involved. (4) The lack of a divergence between the effects of congruent and incongruent primes implies a functional difference between the judgments in the temporal order judgment task and speeded responses that have demonstrated differential effects of congruent and incongruent primes (e.g., Klotz & Neumann, 1999). These results can best be interpreted by assuming that the prime affects perceptual latency by initiating a shift of attention, as suggested by the Asynchronous Updating Model (AUM; Neumann 1978, 1982).

Oligomerization reactions of deoxyribonucleotides on montmorillonite clay - The effect of mononucleotide structure, phosphate activation and montmorillonite composition on phosphodiester bond formation

NASA Technical Reports Server (NTRS)

Ferris, James P.; KAMALUDDIN; Ertem, Gozen

1990-01-01

The 2(prime)-d-5(prime)-GMP and 2(prime)-d-5(prime)-AMP bind 2 times more strongly to montmorillonite 22A than do 2(prime)-d-5(prime)-CMP and 5(prime)-TMP. The dinucleotide d(pG)2 forms in 9.2 percent yield and the cyclic dinucleotide c(dpG)2 in 5.4 percent yield in the reaction of 2(prime)-d-5(prime)-GMP with EDAC in the presence of montmorillonite 22A. The yield of dimers which contain the phosphodiester bond decreases as the reaction medium is changed from 0.2 M NaCl to a mixture of 0.2 M NaCl and 0.075 M MgCl2. A low yield of d(pA)2 was observed in the condensation reaction of 5(prime)-ImdpA on montmorillonite 22A. The yield of d(pA)2 obtained when EDAC is used as the condensing agent increases with increasing iron content of the Na(+)-montmorillonite used as catalyst. Evidence is presented which shows that the acidity of the Na(+)-montmorillonite is a necessary but not sufficient factor for the montmorillonite catalysis of phosphodiester bond formation.

Separability of Abstract-Category and Specific-Exemplar Visual Object Subsystems: Evidence from fMRI Pattern Analysis

PubMed Central

McMenamin, Brenton W.; Deason, Rebecca G.; Steele, Vaughn R.; Koutstaal, Wilma; Marsolek, Chad J.

2014-01-01

Previous research indicates that dissociable neural subsystems underlie abstract-category (AC) recognition and priming of objects (e.g., cat, piano) and specific-exemplar (SE) recognition and priming of objects (e.g., a calico cat, a different calico cat, a grand piano, etc.). However, the degree of separability between these subsystems is not known, despite the importance of this issue for assessing relevant theories. Visual object representations are widely distributed in visual cortex, thus a multivariate pattern analysis (MVPA) approach to analyzing functional magnetic resonance imaging (fMRI) data may be critical for assessing the separability of different kinds of visual object processing. Here we examined the neural representations of visual object categories and visual object exemplars using multi-voxel pattern analyses of brain activity elicited in visual object processing areas during a repetition-priming task. In the encoding phase, participants viewed visual objects and the printed names of other objects. In the subsequent test phase, participants identified objects that were either same-exemplar primed, different-exemplar primed, word-primed, or unprimed. In visual object processing areas, classifiers were trained to distinguish same-exemplar primed objects from word-primed objects. Then, the abilities of these classifiers to discriminate different-exemplar primed objects and word-primed objects (reflecting AC priming) and to discriminate same-exemplar primed objects and different-exemplar primed objects (reflecting SE priming) was assessed. Results indicated that (a) repetition priming in occipital-temporal regions is organized asymmetrically, such that AC priming is more prevalent in the left hemisphere and SE priming is more prevalent in the right hemisphere, and (b) AC and SE subsystems are weakly modular, not strongly modular or unified. PMID:25528436

Separability of abstract-category and specific-exemplar visual object subsystems: evidence from fMRI pattern analysis.

PubMed

McMenamin, Brenton W; Deason, Rebecca G; Steele, Vaughn R; Koutstaal, Wilma; Marsolek, Chad J

2015-02-01

Previous research indicates that dissociable neural subsystems underlie abstract-category (AC) recognition and priming of objects (e.g., cat, piano) and specific-exemplar (SE) recognition and priming of objects (e.g., a calico cat, a different calico cat, a grand piano, etc.). However, the degree of separability between these subsystems is not known, despite the importance of this issue for assessing relevant theories. Visual object representations are widely distributed in visual cortex, thus a multivariate pattern analysis (MVPA) approach to analyzing functional magnetic resonance imaging (fMRI) data may be critical for assessing the separability of different kinds of visual object processing. Here we examined the neural representations of visual object categories and visual object exemplars using multi-voxel pattern analyses of brain activity elicited in visual object processing areas during a repetition-priming task. In the encoding phase, participants viewed visual objects and the printed names of other objects. In the subsequent test phase, participants identified objects that were either same-exemplar primed, different-exemplar primed, word-primed, or unprimed. In visual object processing areas, classifiers were trained to distinguish same-exemplar primed objects from word-primed objects. Then, the abilities of these classifiers to discriminate different-exemplar primed objects and word-primed objects (reflecting AC priming) and to discriminate same-exemplar primed objects and different-exemplar primed objects (reflecting SE priming) was assessed. Results indicated that (a) repetition priming in occipital-temporal regions is organized asymmetrically, such that AC priming is more prevalent in the left hemisphere and SE priming is more prevalent in the right hemisphere, and (b) AC and SE subsystems are weakly modular, not strongly modular or unified. Copyright © 2014 Elsevier Inc. All rights reserved.

Space-valence priming with subliminal and supraliminal words.

PubMed

Ansorge, Ulrich; Khalid, Shah; König, Peter

2013-01-01

To date it is unclear whether (1) awareness-independent non-evaluative semantic processes influence affective semantics and whether (2) awareness-independent affective semantics influence non-evaluative semantic processing. In the current study, we investigated these questions with the help of subliminal (masked) primes and visible targets in a space-valence across-category congruence effect. In line with (1), we found that subliminal space prime words influenced valence classification of supraliminal target words (Experiment 1): classifications were faster with a congruent prime (e.g., the prime "up" before the target "happy") than with an incongruent prime (e.g., the prime "up" before the target "sad"). In contrast to (2), no influence of subliminal valence primes on the classification of supraliminal space targets into up- and down-words was found (Experiment 2). Control conditions showed that standard masked response priming effects were found with both subliminal prime types, and that an across-category congruence effect was also found with supraliminal valence primes and spatial target words. The final Experiment 3 confirmed that the across-category congruence effect indeed reflected priming of target categorization of a relevant meaning category. Together, the data jointly confirmed prediction (1) that awareness-independent non-evaluative semantic priming influences valence judgments.

The energy structure and decay channels of the 4p6-shell excited states in Sr

NASA Astrophysics Data System (ADS)

Kupliauskienė, A.; Kerevičius, G.; Borovik, V.; Shafranyosh, I.; Borovik, A.

2017-11-01

The ejected-electron spectra arising from the decay of the 4p{}5{{nln}}{\\prime }{l}{\\prime }{n}{\\prime\\prime }{l}{\\prime\\prime } autoionizing states in Sr atoms have been studied precisely at the incident-electron energies close to excitation and ionization thresholds of the 4{{{p}}}6 subshell. The excitation behaviors for 58 lines observed between 12 and 21 eV ejected-electron kinetic energy have been investigated. Also, the ab initio calculations of excitation energies, autoionization probabilities and electron-impact excitation cross sections of the states 4p{}5{{nln}}{\\prime }{l}{\\prime }{n}{\\prime\\prime }{l}{\\prime\\prime } (nl = 4d, 5s, 5p; {n}{\\prime }{l}{\\prime } = 4d, 5s, 5p; {n}{\\prime\\prime }{l}{\\prime\\prime } = 5s, 6s, 7s, 8s, 9s, 5p, 6p, 5d, 6d, 7d, 8d, 4f, 5g) have been performed by employing the large-scale configuration-interaction method in the basis of the solutions of Dirac-Fock-Slater equations. The obtained experimental and theoretical data have been used for the accurate identification of the 60 lines in ejected-electron spectra and the 68 lines observed earlier in photoabsorption spectra. The excitation and decay processes for 105 classified states in the 4p55s{}2{nl}, 4p54d{}2{nl} and 4p55s{{nln}}{\\prime }{l}{\\prime } configurations have been considered in detail. In particular, most of the states lying below the ionization threshold of the 4p6 subshell at 26.92 eV possess up to four decay channels with formation of Sr+ in 5s{}1/2, 4d{}3/{2,5/2} and 5p{}1/{2,3/2} states. Two-step autoionization and two-electron Auger transitions with formation of Sr2+ in the 4p6 {}1{{{S}}}0 ground state are the main decay paths for high-lying autoionizing states. The excitation threshold of the 4{{{p}}}6 subshell in Sr has been established at 20.98 ± 0.05 eV.

Inverse Target- and Cue-Priming Effects of Masked Stimuli

ERIC Educational Resources Information Center

Mattler, Uwe

2007-01-01

The processing of a visual target that follows a briefly presented prime stimulus can be facilitated if prime and target stimuli are similar. In contrast to these positive priming effects, inverse priming effects (or negative compatibility effects) have been found when a mask follows prime stimuli before the target stimulus is presented: Responses…

Associative priming in a masked perceptual identification task: evidence for automatic processes.

PubMed

Pecher, Diane; Zeelenberg, René; Raaijmakers, Jeroen G W

2002-10-01

Two experiments investigated the influence of automatic and strategic processes on associative priming effects in a perceptual identification task in which prime-target pairs are briefly presented and masked. In this paradigm, priming is defined as a higher percentage of correctly identified targets for related pairs than for unrelated pairs. In Experiment 1, priming was obtained for mediated word pairs. This mediated priming effect was affected neither by the presence of direct associations nor by the presentation time of the primes, indicating that automatic priming effects play a role in perceptual identification. Experiment 2 showed that the priming effect was not affected by the proportion (.90 vs. .10) of related pairs if primes were presented briefly to prevent their identification. However, a large proportion effect was found when primes were presented for 1000 ms so that they were clearly visible. These results indicate that priming in a masked perceptual identification task is the result of automatic processes and is not affected by strategies. The present paradigm provides a valuable alternative to more commonly used tasks such as lexical decision.

Semantic priming in the lexical decision task: roles of prospective prime-generated expectancies and retrospective semantic matching.

PubMed

Neely, J H; Keefe, D E; Ross, K L

1989-11-01

In semantic priming paradigms for lexical decisions, the probability that a word target is semantically related to its prime (the relatedness proportion) has been confounded with the probability that a target is a nonword, given that it is unrelated to its prime (the nonword ratio). This study unconfounded these two probabilities in a lexical decision task with category names as primes and with high- and low-dominance exemplars as targets. Semantic priming for high-dominance exemplars was modulated by the relatedness proportion and, to a lesser degree, by the nonword ratio. However, the nonword ratio exerted a stronger influence than did the relatedness proportion on semantic priming for low-dominance exemplars and on the nonword facilitation effect (i.e., the superiority in performance for nonword targets that follow a category name rather than a neutral XXX prime). These results suggest that semantic priming for lexical decisions is affected by both a prospective prime-generated expectancy, modulated by the relatedness proportion, and a retrospective target/prime semantic matching process, modulated by the nonword ratio.

An investigation of time course of category and semantic priming.

PubMed

Ray, Suchismita

2008-04-01

Low semantically similar exemplars in a category demonstrate the category-priming effect through priming of the category (i.e., exemplar-category-exemplar), whereas high semantically similar exemplars in the same category demonstrate the semantic-priming effect (i.e., direct activation of one high semantically similar exemplar by another). The author asked whether the category- and semantic-priming effects are based on a common memory process. She examined this question by testing the time courses of category- and semantic-priming effects. She tested participants on either category- or semantic-priming paradigm at 2 different time intervals (6 min and 42 min) by using a lexical decision task using exemplars from categories. Results showed that the time course of category priming was different from that of semantic priming. The author concludes that these 2 priming effects are based on 2 separate memory processes.

PCB and DDE methyl sulfones in mammals from Canada and Sweden

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bergman, A.; Kuroki, Hiroaki; Norstrom, R.J.

1994-01-01

Levels of PCB methyl sulfones (MeSO[sub 2]-CBs) and DDE methyl sulfones (MeSO[sub 2]-DDEs) have been determined in tissues from polar bear (Ursus martimus), beluga whale (Delphinapterus leucas), and false killer whale (Pseudorca crassidens) from the Canadian environment, and grey seal (Halichoerus grypus), otter (Lutra lutra), and wild mink (Mustela vison) from the Swedish environment. Up to 30 MeSO[sub 2]-CB congeners and three MeSO[sub 2]-DdE isomers were shown to be present in the analyzed tissues. The concentration of total MeSO[sub 2]-CBs ranged from 0.1 to 21 [mu]g/g extracted lipids. 3-MeSO[sub 2]-2,5,2[prime],4[prime],5[prime]-penta-CB is the dominating MeSO[sub 2]-CB congener in all the analyzedmore » samples, but the corresponding 4-MeSO[sub 2]-CB also is present in high concentrations. A smaller number of MeSO[sub 2]-CBs, always dominated by the meta-substituted MeSO[sub 2]-CBs, were present in livers of grey seal, otter, and mink than in adipose tissue or muscle. In all studied mammals the concentration of MeSO[sub 2]-CBs were higher in liver than in blubber or muscle. Seven PCB congeners were identified as precursors of the PCB methyl sulfones: 2,4,2[prime],5[prime]-tetra-CB (CB-49),2,5,3[prime],4[prime]-tetra-CB (CB-70), 2,4,5,2[prime],5[prime]-penta-CB (CB-101),2,3,4,5,2[prime],5[prime]-penta-CB (CB-87),2,3,6,2[prime],4[prime],5[prime]-hexa-CB (CB-149),2,3,4,2[prime],3[prime],6[prime]-hexa-CB (CB-132), and 2,3,4,2[prime],5[prime]-hexa-CB (CB-141). All species except beluga whale contained 3-MeSO[sub 2]-4,4[prime]-DDE, but at a much lower concentration in mink and otter than in the other mammals. Polar bear and grey seal liver also contained 2-MeSO[sub 2]-4,4[prime]-DDE. The concentration of 2- and 3-MeSo[sub 2]-DDE ranged from 0.01 to 1.3 [mu]g/g extracted lipids.« less

Spatial frequency filtered images reveal differences between masked and unmasked processing of emotional information.

PubMed

Rohr, Michaela; Wentura, Dirk

2014-10-01

High and low spatial frequency information has been shown to contribute differently to the processing of emotional information. In three priming studies using spatial frequency filtered emotional face primes, emotional face targets, and an emotion categorization task, we investigated this issue further. Differences in the pattern of results between short and masked, and short and long unmasked presentation conditions emerged. Given long and unmasked prime presentation, high and low frequency primes triggered emotion-specific priming effects. Given brief and masked prime presentation in Experiment 2, we found a dissociation: High frequency primes caused a valence priming effect, whereas low frequency primes yielded a differentiation between low and high arousing information within the negative domain. Brief and unmasked prime presentation in Experiment 3 revealed that subliminal processing of primes was responsible for the pattern observed in Experiment 2. The implications of these findings for theories of early emotional information processing are discussed. Copyright © 2014 Elsevier Inc. All rights reserved.

Relational integrativity of prime-target pairs moderates congruity effects in evaluative priming.

PubMed

Ihmels, Max; Freytag, Peter; Fiedler, Klaus; Alexopoulos, Theodore

2016-05-01

In evaluative priming, positive or negative primes facilitate reactions to targets that share the same valence. While this effect is commonly explained as reflecting invariant structures in semantic long-term memory or in the sensorimotor system, the present research highlights the role of integrativity in evaluative priming. Integrativity refers to the ease of integrating two concepts into a new meaningful compound representation. In extended material tests using paired comparisons from two pools of positive and negative words, we show that evaluative congruity is highly correlated with integrativity. Therefore, in most priming studies, congruity and integrativity are strongly confounded. When both aspects are disentangled by manipulating congruity and integrativity orthogonally, three priming experiments show that evaluative-priming effects were confined to integrative prime-target pairs. No facilitation of prime-congruent targets was obtained for non-integrative stimuli. These findings are discussed from a broader perspective on priming conceived as flexible, context-dependent, and serving a generative adaptation function.

On the effect of subliminal priming on subjective perception of images: a machine learning approach.

PubMed

Kumar, Parmod; Mahmood, Faisal; Mohan, Dhanya Menoth; Wong, Ken; Agrawal, Abhishek; Elgendi, Mohamed; Shukla, Rohit; Dauwels, Justin; Chan, Alice H D

2014-01-01

The research presented in this article investigates the influence of subliminal prime words on peoples' judgment about images, through electroencephalograms (EEGs). In this cross domain priming paradigm, the participants are asked to rate how much they like the stimulus images, on a 7-point Likert scale, after being subliminally exposed to masked lexical prime words, with EEG recorded simultaneously. Statistical analysis tools are used to analyze the effect of priming on behavior, and machine learning techniques to infer the primes from EEGs. The experiment reveals strong effects of subliminal priming on the participants' explicit rating of images. The subjective judgment affected by the priming makes visible change in event-related potentials (ERPs); results show larger ERP amplitude for the negative primes compared with positive and neutral primes. In addition, Support Vector Machine (SVM) based classifiers are proposed to infer the prime types from the average ERPs, which yields a classification rate of 70%.

Selective impairment of masked priming in dual-task performance.

PubMed

Fischer, Rico; Kiesel, Andrea; Kunde, Wilfried; Schubert, Torsten

2011-03-01

This study investigated the impact of divided attention on masked priming. In a dual-task setting, two tasks had to be carried out in close temporal succession: a tone discrimination task and a masked priming task. The order of the tasks was varied between experiments, and attention was always allocated to the first task-that is, the first task was prioritized. The priming task was the second (nonprioritized) task in Experiment 1 and the first (prioritized) task in Experiment 2. In both experiments, "novel" prime stimuli associated with semantic processing were essentially ineffective. However, there was intact priming by another type of prime stimuli associated with response priming. Experiment 3 showed that all these prime stimuli can reveal significant priming effects during a task-switching paradigm in which both tasks were performed consecutively. We conclude that dual-task specific interference processes (e.g., the simultaneous coordination of multiple stimulus-response rules) selectively impair priming that is assumed to rely on semantic processing.

Boundary conditions for the influence of unfamiliar non-target primes in unconscious evaluative priming: The moderating role of attentional task sets.

PubMed

Kiefer, Markus; Sim, Eun-Jim; Wentura, Dirk

2015-09-01

Evaluative priming by masked emotional stimuli that are not consciously perceived has been taken as evidence that affective stimulus evaluation can also occur unconsciously. However, as masked priming effects were small and frequently observed only for familiar primes that there also presented as visible targets in an evaluative decision task, priming was thought to reflect primarily response activation based on acquired S-R associations and not evaluative semantic stimulus analysis. The present study therefore assessed across three experiments boundary conditions for the emergence of masked evaluative priming effects with unfamiliar primes in an evaluative decision task and investigated the role of the frequency of target repetition on priming with pictorial and verbal stimuli. While familiar primes elicited robust priming effects in all conditions, priming effects by unfamiliar primes were reliably obtained for low repetition (pictures) or unrepeated targets (words), but not for targets repeated at a high frequency. This suggests that unfamiliar masked stimuli only elicit evaluative priming effects when the task set associated with the visible target involves evaluative semantic analysis and is not based on S-R triggered responding as for high repetition targets. The present results therefore converge with the growing body of evidence demonstrating attentional control influences on unconscious processing. Copyright © 2015 Elsevier Inc. All rights reserved.

Separate Brain Circuits Support Integrative and Semantic Priming in the Human Language System.

PubMed

Feng, Gangyi; Chen, Qi; Zhu, Zude; Wang, Suiping

2016-07-01

Semantic priming is a crucial phenomenon to study the organization of semantic memory. A novel type of priming effect, integrative priming, has been identified behaviorally, whereby a prime word facilitates recognition of a target word when the 2 concepts can be combined to form a unitary representation. We used both functional and anatomical imaging approaches to investigate the neural substrates supporting such integrative priming, and compare them with those in semantic priming. Similar behavioral priming effects for both semantic (Bread-Cake) and integrative conditions (Cherry-Cake) were observed when compared with an unrelated condition. However, a clearly dissociated brain response was observed between these 2 types of priming. The semantic-priming effect was localized to the posterior superior temporal and middle temporal gyrus. In contrast, the integrative-priming effect localized to the left anterior inferior frontal gyrus and left anterior temporal cortices. Furthermore, fiber tractography showed that the integrative-priming regions were connected via uncinate fasciculus fiber bundle forming an integrative circuit, whereas the semantic-priming regions connected to the posterior frontal cortex via separated pathways. The results point to dissociable neural pathways underlying the 2 distinct types of priming, illuminating the neural circuitry organization of semantic representation and integration. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Confusion and Compensation in Visual Perception: Effects of Spatiotemporal Proximity and Selective Attention

ERIC Educational Resources Information Center

Weidemann, Christoph T.; Huber, David E.; Shiffrin, Richard M.

2005-01-01

The authors investigated spatial, temporal, and attentional manipulations in a short-term repetition priming paradigm. Brief primes produced a strong preference to choose the primed alternative, whereas long primes had the opposite effect. However, a 2nd brief presentation of a long prime produced a preference for the primed word despite the long…

SOA Does Not Reveal the Absolute Time Course of Cognitive Processing in Fast Priming Experiments

ERIC Educational Resources Information Center

Tzur, Boaz; Frost, Ram

2007-01-01

Applying Bloch's law to visual word recognition research, both exposure duration of the prime and its luminance determine the prime's overall energy, and consequently determine the size of the priming effect. Nevertheless, experimenters using fast-priming paradigms traditionally focus only on the SOA between prime and target to reflect the…

Influence of prime-target relationship on semantic priming effects from words in a lexical-decision task.

PubMed

Abad, María J F; Noguera, Carmen; Ortells, Juan J

2003-07-01

The present research examines the influence of prime-target relationship (associative and categorical versus categorical only) on priming effects from attended and ignored parafoveal words. Participants performed a lexical-decision task on a single central target, which was preceded by two parafoveal prime words, one of which (the attended prime) was spatially precued. The results showed reliable positive and negative priming effects from attended and ignored words, respectively. However, this priming pattern was observed only for the "associative and categorical", but not for the "categorical only" relationship condition. These results suggest that the lack of semantic priming effects from words in some prior studies may be attributed to the kind of material used (i.e. weakly-associated word pairs).

Visual priming within and across symbolic format using a tachistoscopic picture identification task: a PET study.

PubMed

Lebreton, K; Desgranges, B; Landeau, B; Baron, J C; Eustache, F

2001-07-01

The present work was aimed at characterizing picture priming effects from two complementary behavioral and functional neuroimaging (positron emission tomography, PET) studies. In two experiments, we used the same line drawings of common living/nonliving objects in a tachistoscopic identification task to contrast two forms of priming. In the within-format priming condition (picture-picture), subjects were instructed to perform a perceptual encoding task in the study phase, whereas in the cross-format priming condition (word-picture), they were instructed to perform a semantic encoding task. In Experiment 1, we showed significant priming effects in both priming conditions. However, the magnitude of priming effects in the same-format/perceptual encoding condition was higher than that in the different-format/semantic encoding condition, while the recognition performance did not differ between the two conditions. This finding supports the existence of two forms of priming that may be subserved by different systems. Consistent with these behavioral findings, the PET data for Experiment 2 revealed distinct priming-related patterns of regional cerebral blood flow (rCBF) decreases for the two priming conditions when primed items were compared to unprimed items. The same-format priming condition involved reductions in cerebral activity particularly in the right extrastriate cortex and left cerebellum, while the different-format priming condition was associated with rCBF decreases in the left inferior temporo-occipital cortex, left frontal regions, and the right cerebellum. These results suggest that the extrastriate cortex may subserve general aspects of perceptual priming, independent of the kind of stimuli, and that the right part of this cortex could underlie the same-format-specific system for pictures. These data also support the idea that the cross-format/semantic encoding priming for pictures represents a form of lexico-semantic priming subserved by a semantic neural network extending from left temporo-occipital cortex to left frontal regions. These results reinforce the distinction between perceptual and conceptual priming for pictures, indicating that different cerebral processes and systems are implicated in these two forms of picture priming.

Mechanisms of masked evaluative priming: task sets modulate behavioral and electrophysiological priming for picture and words differentially

PubMed Central

Liegel, Nathalie; Zovko, Monika; Wentura, Dirk

2017-01-01

Abstract Research with the evaluative priming paradigm has shown that affective evaluation processes reliably influence cognition and behavior, even when triggered outside awareness. However, the precise mechanisms underlying such subliminal evaluative priming effects, response activation vs semantic processing, are matter of a debate. In this study, we determined the relative contribution of semantic processing and response activation to masked evaluative priming with pictures and words. To this end, we investigated the modulation of masked pictorial vs verbal priming by previously activated perceptual vs semantic task sets and assessed the electrophysiological correlates of priming using event-related potential (ERP) recordings. Behavioral and electrophysiological effects showed a differential modulation of pictorial and verbal subliminal priming by previously activated task sets: Pictorial priming was only observed during the perceptual but not during the semantic task set. Verbal priming, in contrast, was found when either task set was activated. Furthermore, only verbal priming was associated with a modulation of the N400 ERP component, an index of semantic processing, whereas a priming-related modulation of earlier ERPs, indexing visuo-motor S-R activation, was found for both picture and words. The results thus demonstrate that different neuro-cognitive processes contribute to unconscious evaluative priming depending on the stimulus format. PMID:27998994

Space-Valence Priming with Subliminal and Supraliminal Words

PubMed Central

Ansorge, Ulrich; Khalid, Shah; König, Peter

2013-01-01

To date it is unclear whether (1) awareness-independent non-evaluative semantic processes influence affective semantics and whether (2) awareness-independent affective semantics influence non-evaluative semantic processing. In the current study, we investigated these questions with the help of subliminal (masked) primes and visible targets in a space-valence across-category congruence effect. In line with (1), we found that subliminal space prime words influenced valence classification of supraliminal target words (Experiment 1): classifications were faster with a congruent prime (e.g., the prime “up” before the target “happy”) than with an incongruent prime (e.g., the prime “up” before the target “sad”). In contrast to (2), no influence of subliminal valence primes on the classification of supraliminal space targets into up- and down-words was found (Experiment 2). Control conditions showed that standard masked response priming effects were found with both subliminal prime types, and that an across-category congruence effect was also found with supraliminal valence primes and spatial target words. The final Experiment 3 confirmed that the across-category congruence effect indeed reflected priming of target categorization of a relevant meaning category. Together, the data jointly confirmed prediction (1) that awareness-independent non-evaluative semantic priming influences valence judgments. PMID:23439863

Contextual influences on implicit evaluation: a test of additive versus contrastive effects of evaluative context stimuli in affective priming.

PubMed

Gawronski, Bertram; Deutsch, Roland; Seidel, Oliver

2005-09-01

Drawing on two alternative accounts of the affective priming effect (spreading activation vs. response interference), the present research investigated the underlying processes of how evaluative context stimuli influence implicit evaluations in the affective priming task. Employing two sequentially presented prime stimuli (rather than a single prime), two experiments showed that affective priming effects elicited by a given prime stimulus were more pronounced when this stimulus was preceded by a context prime of the opposite valence than when it was preceded by a context prime of the same valence. This effect consistently emerged for pictures (Experiment 1) and words (Experiment 2) as prime stimuli. These results suggest that the impact of evaluative context stimuli on implicit evaluations is mediated by contrast effects in the attention to evaluative information rather than by additive effects in the activation of evaluative information in associative memory.

Test-retest reliability of subliminal facial affective priming.

PubMed

Dannlowski, Udo; Suslow, Thomas

2006-02-01

Since the seminal 1993 demonstrations o f Murphy an d Zajonc, researchers have replicated and extended findings concerning subliminal affective priming. So far, however, no data on test-retest reliability of affective priming effects are available. A subliminal facial affective priming task was administered to 22 healthy individuals (15 women and 7 men) twice about 7 wk. apart. Happy and sad facial expressions were used as affective primes and neutral Chinese ideographs served as target masks, which had to be evaluated. Neutral facial primes and a no-face condition served as baselines. All participants reported not having seen any of the prime faces at either testing session. Priming scores for affective faces compared to the baselines were computed. Acceptable test-retest correlations (rs) of up to .74 were found for the affective priming scores. Although measured almost 2 mo. apart, subliminal affective priming seems to be a temporally stable effect.

From primed construct to motivated behavior: validation processes in goal pursuit.

PubMed

Demarree, Kenneth G; Loersch, Chris; Briñol, Pablo; Petty, Richard E; Payne, B Keith; Rucker, Derek D

2012-12-01

Past research has found that primes can automatically initiate unconscious goal striving. Recent models of priming have suggested that this effect can be moderated by validation processes. According to a goal-validation perspective, primes should cause changes in one's motivational state to the extent people have confidence in the prime-related mental content. Across three experiments, we provided the first direct empirical evidence for this goal-validation account. Using a variety of goal priming manipulations (cooperation vs. competition, achievement, and self-improvement vs. saving money) and validity inductions (power, ease, and writing about confidence), we demonstrated that the impact of goal primes on behavior occurs to a greater extent when conditions foster confidence (vs. doubt) in mental contents. Indeed, when conditions foster doubt, goal priming effects are eliminated or counter to the implications of the prime. The implications of these findings for research on goal priming and validation processes are discussed.

Perceiving age and gender in unfamiliar faces: brain potential evidence for implicit and explicit person categorization.

PubMed

Wiese, Holger; Schweinberger, Stefan R; Neumann, Markus F

2008-11-01

We used repetition priming to investigate implicit and explicit processes of unfamiliar face categorization. During prime and test phases, participants categorized unfamiliar faces according to either age or gender. Faces presented at test were either new or primed in a task-congruent (same task during priming and test) or incongruent (different tasks) condition. During age categorization, reaction times revealed significant priming for both priming conditions, and event-related potentials yielded an increased N170 over the left hemisphere as a result of priming. During gender categorization, congruent faces elicited priming and a latency decrease in the right N170. Accordingly, information about age is extracted irrespective of processing demands, and priming facilitates the extraction of feature information reflected in the left N170 effect. By contrast, priming of gender categorization may depend on whether the task at initial presentation requires configural processing.

The affective regulation of cognitive priming.

PubMed

Storbeck, Justin; Clore, Gerald L

2008-04-01

Semantic and affective priming are classic effects observed in cognitive and social psychology, respectively. The authors discovered that affect regulates such priming effects. In Experiment 1, positive and negative moods were induced before one of three priming tasks; evaluation, categorization, or lexical decision. As predicted, positive affect led to both affective priming (evaluation task) and semantic priming (category and lexical decision tasks). However, negative affect inhibited such effects. In Experiment 2, participants in their natural affective state completed the same priming tasks as in Experiment 1. As expected, affective priming (evaluation task) and category priming (categorization and lexical decision tasks) were observed in such resting affective states. Hence, the authors conclude that negative affect inhibits semantic and affective priming. These results support recent theoretical models, which suggest that positive affect promotes associations among strong and weak concepts, and that negative affect impairs such associations (Clore & Storbeck, 2006; Kuhl, 2000). (Copyright) 2008 APA.

Attachment Security Balances Perspectives: Effects of Security Priming on Highly Optimistic and Pessimistic Explanatory Styles.

PubMed

Deng, Yanhe; Yan, Mengge; Chen, Henry; Sun, Xin; Zhang, Peng; Zeng, Xianglong; Liu, Xiangping; Lye, Yue

2016-01-01

Highly optimistic explanatory style (HOES) and highly pessimistic explanatory style (HPES) are two maladaptive ways to explain the world and may have roots in attachment insecurity. The current study aims to explore the effects of security priming - activating supportive representations of attachment security - on ameliorating these maladaptive explanatory styles. 57 participants with HOES and 57 participants with HPES were randomized into security priming and control conditions. Their scores of overall optimistic attribution were measured before and after priming. Security priming had a moderating effect: the security primed HOES group exhibited lower optimistic attribution, while the security primed HPES group evinced higher scores of optimistic attribution. Furthermore, the security primed HOES group attributed positive outcomes more externally, while the security primed HPES group attributed successful results more internally. The results support the application of security priming interventions on maladaptive explanatory styles. Its potential mechanism and directions for future study are also discussed.

Affective priming using facial expressions modulates liking for abstract art.

PubMed

Flexas, Albert; Rosselló, Jaume; Christensen, Julia F; Nadal, Marcos; Olivera La Rosa, Antonio; Munar, Enric

2013-01-01

We examined the influence of affective priming on the appreciation of abstract artworks using an evaluative priming task. Facial primes (showing happiness, disgust or no emotion) were presented under brief (Stimulus Onset Asynchrony, SOA = 20 ms) and extended (SOA = 300 ms) conditions. Differences in aesthetic liking for abstract paintings depending on the emotion expressed in the preceding primes provided a measure of the priming effect. The results showed that, for the extended SOA, artworks were liked more when preceded by happiness primes and less when preceded by disgust primes. Facial expressions of happiness, though not of disgust, exerted similar effects in the brief SOA condition. Subjective measures and a forced-choice task revealed no evidence of prime awareness in the suboptimal condition. Our results are congruent with findings showing that the affective transfer elicited by priming biases evaluative judgments, extending previous research to the domain of aesthetic appreciation.

Affective Priming Using Facial Expressions Modulates Liking for Abstract Art

PubMed Central

Flexas, Albert; Rosselló, Jaume; Christensen, Julia F.; Nadal, Marcos; Olivera La Rosa, Antonio; Munar, Enric

2013-01-01

We examined the influence of affective priming on the appreciation of abstract artworks using an evaluative priming task. Facial primes (showing happiness, disgust or no emotion) were presented under brief (Stimulus Onset Asynchrony, SOA = 20ms) and extended (SOA = 300ms) conditions. Differences in aesthetic liking for abstract paintings depending on the emotion expressed in the preceding primes provided a measure of the priming effect. The results showed that, for the extended SOA, artworks were liked more when preceded by happiness primes and less when preceded by disgust primes. Facial expressions of happiness, though not of disgust, exerted similar effects in the brief SOA condition. Subjective measures and a forced-choice task revealed no evidence of prime awareness in the suboptimal condition. Our results are congruent with findings showing that the affective transfer elicited by priming biases evaluative judgments, extending previous research to the domain of aesthetic appreciation. PMID:24260350

Need for cognition can magnify or attenuate priming effects in social judgment.

PubMed

Petty, Richard E; DeMarree, Kenneth G; Briñol, Pablo; Horcajo, Javier; Strathman, Alan J

2008-07-01

This article hypothesizes that the individual-difference variable, need for cognition (NFC), can have opposite implications for priming effects, depending on prime blatancy. Subtle primes are argued to be more effective for high- versus low-NFC individuals. This is because for high-NFC individuals, (a) constructs are generally easier to activate, (b) their higher amount of thought offers more opportunity for an activated construct to bias judgment, and (c) their thoughtfully formed judgments are more likely to affect behavior. However, because high-NFC individuals are adept at identifying and correcting for bias, with blatant primes the activated construct should be less likely to exert its default influence. Furthermore, with blatant primes, low-NFC individuals may achieve sufficient activation for primes to affect judgment. Across three studies, it is shown that as NFC increases, the magnitude of priming effects increases with a subtle prime but decreases with a blatant prime.

The temporal dynamics of masked repetition picture priming effects: manipulations of stimulus-onset asynchrony (SOA) and prime duration

PubMed Central

Eddy, Marianna D.; Holcomb, Phillip J.

2010-01-01

The current study used event-related potentials (ERPs) and masked repetition priming to examine the time-course of picture processing. We manipulated the stimulus-onset asynchrony (110 ms, 230 ms, 350 ms, 470 ms) between repeated and unrepeated prime-target pairs while holding the prime duration constant (50 ms) (Experiment 1) as well as the prime duration (30 ms, 50 ms, 70 ms, 90 ms) (Experiment 2) with a constant SOA of 110 ms in a masked repetition priming paradigm with pictures. The aim of this study was to further elucidate the mechanisms underlying previously observed ERP components in masked priming with pictures. We found both the N/P190 and N400 are modulated by changes in prime duration and SOA, however, it appears that longer prime exposure rather than a longer SOA leads to more in-depth processing as indexed by larger N400 effects. PMID:20403342

Does retained-seed priming drive the evolution of serotiny in drylands? An assessment using the cactus Mammillaria hernandezii.

PubMed

Santini, Bianca A; Martorell, Carlos

2013-02-01

Serotinous plants retain their seeds for a long time. In deserts, retained seeds undergo hydration-dehydration cycles and thus may become primed. Priming enhances germination and seedling vigor. We test the hypothesis that serotiny evolves because it provides a site protected from predators in which seeds can become primed. Rainfall-cued dispersal of primed seeds may enhance this effect. We tested this hypothesis with Mammillaria hernandezii through protein-content analyses; field and laboratory germination experiments with primed, unprimed, and retained seeds; and fitness estimations from demographic models. Hydration-dehydration cycles induced priming, enhancing germination. Artificial priming and retention in the parent plant for 1 yr induced similar changes in seed protein patterns, suggesting that priming occurs naturally while seeds are retained. Under field conditions, germination of seeds retained for 1 yr more than doubled that of seeds of the same cohort that were not primed or that remained buried for 1 yr. The first seeds to germinate died rapidly. Serotinous plants whose seeds underwent priming had higher fitness than those whose seeds were in the soil seed bank or that did not experience priming. Priming in soil seed banks may be costly because of high predation, so seed protection during priming is sufficient to promote the evolution of serotiny. Bet hedging contributes to this process. Rapid germination of primed seeds that respond to brief rainfall events is disadvantageous because such rainfall is insufficient for seedling survival. Serotinous species counteract this cost by cueing dispersal with heavy precipitation.

Macrocyclic polyaminocarboxylates for stable radiometal antibody conjugates for therapy, SPECT and PET imaging

DOEpatents

Mease, R.C.; Mausner, L.F.; Srivastava, S.C.

1997-06-17

A simple method for the synthesis of 1,4,7, 10-tetraazacyclododecane N,N{prime}N{double_prime},N{prime}{double_prime}-tetraacetic acid and 1,4,8,11-tetraazacyclotetradecane N,N{prime},N{double_prime},N{prime}{double_prime}-tetraacetic acid involves cyanomethylating 1,4,7,10-tetraazacyclododecane or 1,4,8,11-tetraazacyclotetradecane to form a tetranitrile and hydrolyzing the tetranitrile. These macrocyclic compounds are functionalized through one of the carboxylates and then conjugated to various biological molecules including monoclonal antibodies. The resulting conjugated molecules are labeled with radiometals for SPECT and PET imaging and for radiotherapy. 4 figs.

False memories and lexical decision: even twelve primes do not cause long-term semantic priming.

PubMed

Zeelenberg, René; Pecher, Diane

2002-03-01

Semantic priming effects are usually obtained only if the prime is presented shortly before the target stimulus. Recent evidence obtained with the so-called false memory paradigm suggests, however, that in both explicit and implicit memory tasks semantic relations between words can result in long-lasting effects when multiple 'primes' are presented. The aim of the present study was to investigate whether these effects would generalize to lexical decision. In four experiments we showed that even as many as 12 primes do not cause long-term semantic priming. In all experiments, however, a repetition priming effect was obtained. The present results are consistent with a number of other results showing that semantic information plays a minimal role in long-term priming in visual word recognition.

Priming of disability and elderly stereotype in motor performance: similar or specific effects?

PubMed

Ginsberg, Frederik; Rohmer, Odile; Louvet, Eva

2012-04-01

In three experimental studies, the effects of priming participants with the disability stereotype were investigated with respect to their subsequent motor performance. Also explored were effects of activating two similar stereotypes, persons with a disability and elderly people. In Study 1, participants were primed with the disability stereotype versus with a neutral prime, and then asked to perform on a motor coordination task. In Studies 2 and 3, a third condition was introduced: priming participants with the elderly stereotype. Results indicated that priming participants with the disability stereotype altered their motor performance: they showed decreased manual dexterity and performed slower than the non-primed participants. Priming with the elderly stereotype decreased only performance speed. These findings underline that prime-to-behavior effects may depend on activation of specific stereotype content.

Ablation of SLP-76 signaling after T cell priming generates memory CD4 T cells impaired in steady-state and cytokine-driven homeostasis.

PubMed

Bushar, Nicholas D; Corbo, Evann; Schmidt, Michelle; Maltzman, Jonathan S; Farber, Donna L

2010-01-12

The intracellular signaling mechanisms regulating the generation and long-term persistence of memory T cells in vivo remain unclear. In this study, we used mouse models with conditional deletion of the key T cell receptor (TCR)-coupled adaptor molecule SH2-domain-containing phosphoprotein of 76 kDa (SLP-76), to analyze signaling mechanisms for memory CD4 T cell generation, maintenance, and homeostasis. We found that ablation of SLP-76 expression after T cell priming did not inhibit generation of phenotypic effector or memory CD4 T cells; however, the resultant SLP-76-deficient memory CD4 T cells could not produce recall cytokines in response to TCR-mediated stimulation and showed decreased persistence in vivo. In addition, SLP-76-deficient memory CD4 T cells exhibited reduced steady-state homeostasis and were impaired in their ability to homeostatically expand in vivo in response to the gamma(c) cytokine IL-7, despite intact proximal signaling through the IL-7R-coupled JAK3/STAT5 pathway. Direct in vivo deletion of SLP-76 in polyclonal memory CD4 T cells likewise led to impaired steady-state homeostasis as well as impaired homeostatic responses to IL-7. Our findings demonstrate a dominant role for SLP-76-dependent TCR signals in regulating turnover and perpetuation of memory CD4 T cells and their responses to homeostatic cytokines, with implications for the selective survival of memory CD4 T cells following pathogen exposure, vaccination, and aging.

Monocyte-derived dendritic cells induce a house dust mite-specific Th2 allergic inflammation in the lung of humanized SCID mice: involvement of CCR7.

PubMed

Hammad, Hamida; Lambrecht, Bart N; Pochard, Pierre; Gosset, Philippe; Marquillies, Philippe; Tonnel, André-Bernard; Pestel, Joël

2002-08-01

In rodents, airway dendritic cells (DCs) capture inhaled Ag, undergo maturation, and migrate to the draining mediastinal lymph nodes (MLN) to initiate the Ag-specific T cell response. However, the role of human DCs in the pathogenesis of the Th2 cell-mediated disease asthma remains to be clarified. Here, by using SCID mice engrafted with T cells from either house dust mite (HDM)-allergic patients or healthy donors, we show that DCs pulsed with Der p 1, one of the major allergens of HDM, and injected intratracheally into naive animals migrated into the MLN. In the MLN, Der p 1-pulsed DCs from allergic patients induced the proliferation of IL-4-producing CD4(+) T cells, whereas those from healthy donors induced IFN-gamma-secreting cells. In reconstituted human PBMC-reconstituted SCID mice primed with pulsed DCs from allergic patients, repeated exposure to aerosols of HDM induced 1) a strong pulmonary inflammatory reaction rich in T cells and eosinophils, 2) an increase in IL-4 and IL-5 production in the lung lavage fluid, and 3) increased IgE production compared with that in mice primed with unpulsed DCs. All these effects were reduced following in vivo neutralization of the CCR7 ligand secondary lymphoid tissue chemokine. These data in human PBMC-reconstituted SCID mice show that monocyte-derived DCs might play a key role in the pathogenesis of the pulmonary allergic response by inducing Th2 effector function following migration to the MLN.

A SUITABLE TRITIUM CARRIER FOR GAS DISCHARGE TUBES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reifenschweiler, O.

1959-10-31

The application, especially in manufacturing processes, of radium and similar radioactive materials as priming agents in gas discharge tubes is very undesirable owing to the danger to health which they involve. To avoid this danger or to diminish it as much as possible, various attempts were made to employ tritium as a priming agent. This radioactive gas is especially suitable for this purpose because of its extremely soft beta radiation, the absence of hard gamma radiation, its high specific activity at a relatively low price, and above all its extremely high maximum permissible concentration in comparison with radium. To avoidmore » the handling of gaseous tritium, which is undesirable in manufacturing processes, the tritium is applied in a suspension of a tritiated titunium powder. On account of the small energy of the beta particles the grains of this titunium powder have to be extremely small. A powder prepared by careful milling and elutriation with grains of about 1 mu proved to be much too coarse. Only a few percent of the beta particles of the tritium then leave the titunium grains. However, by evaporation of titanium in an atmosphere of rare gases, a powder with a grain diameter of about 300 A is obtained. After absorption of the tritium by this titanium powder a suspension in an organic fluid is prepared by ultrasonic treatment. The electron-emitter surface is then very conveniently obtained by painting this suspension at the desired bremsstrahlung by means of a Geiger counter. The loss of electrons by absorption in the titanium is then only about 10%. (auth)« less

Immune Regulatory Properties of CD117pos Amniotic Fluid Stem Cells Vary According to Gestational Age

PubMed Central

Di Trapani, Mariano; Bassi, Giulio; Fontana, Emanuela; Giacomello, Luca; Pozzobon, Michela; Guillot, Pascale V.; De Coppi, Paolo

2015-01-01

Amniotic Fluid Stem (AFS) cells are broadly multipotent fetal stem cells derived from the positive selection and ex vivo expansion of amniotic fluid CD117/c-kitpos cells. Considering the differentiation potential in vitro toward cell lineages belonging to the three germ layers, AFS cells have raised great interest as a new therapeutic tool, but their immune properties still need to be assessed. We analyzed the in vitro immunological properties of AFS cells from different gestational age in coculture with T, B, and natural killer (NK) cells. Nonactivated (resting) first trimester-AFS cells showed lower expression of HLA class-I molecules and NK-activating ligands than second and third trimester-AFS cells, whose features were associated with lower sensitivity to NK cell-mediated lysis. Nevertheless, inflammatory priming with interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) enhanced resistance of all AFS cell types to NK cytotoxicity. AFS cells modulated lymphocyte proliferation in a different manner according to gestational age: first trimester-AFS cells significantly inhibited T and NK cell proliferation, while second and third trimester-AFS cells were less efficient. In addition, only inflammatory-primed second trimester-AFS cells could suppress B cell proliferation, which was not affected by the first and third trimester-AFS cells. Indolamine 2,3 dioxygenase pathway was significantly involved only in T cell suppression mediated by second and third trimester-AFS cells. Overall, this study shows a number of significant quantitative differences among AFS cells of different gestational age that have to be considered in view of their clinical application. PMID:25072397

Non-induction of radioadaptive response in zebrafish embryos by neutrons

PubMed Central

Ng, Candy Y.P.; Kong, Eva Y.; Kobayashi, Alisa; Suya, Noriyoshi; Uchihori, Yukio; Cheng, Shuk Han; Konishi, Teruaki; Yu, Kwan Ngok

2016-01-01

In vivo neutron-induced radioadaptive response (RAR) was studied using zebrafish (Danio rerio) embryos. The Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility at the National Institute of Radiological Sciences (NIRS), Japan, was employed to provide 2-MeV neutrons. Neutron doses of 0.6, 1, 25, 50 and 100 mGy were chosen as priming doses. An X-ray dose of 2 Gy was chosen as the challenging dose. Zebrafish embryos were dechorionated at 4 h post fertilization (hpf), irradiated with a chosen neutron dose at 5 hpf and the X-ray dose at 10 hpf. The responses of embryos were assessed at 25 hpf through the number of apoptotic signals. None of the neutron doses studied could induce RAR. Non-induction of RAR in embryos having received 0.6- and 1-mGy neutron doses was attributed to neutron-induced hormesis, which maintained the number of damaged cells at below the threshold for RAR induction. On the other hand, non-induction of RAR in embryos having received 25-, 50- and 100-mGy neutron doses was explained by gamma-ray hormesis, which mitigated neutron-induced damages through triggering high-fidelity DNA repair and removal of aberrant cells through apoptosis. Separate experimental results were obtained to verify that high-energy photons could disable RAR. Specifically, 5- or 10-mGy X-rays disabled the RAR induced by a priming dose of 0.88 mGy of alpha particles delivered to 5-hpf zebrafish embryos against a challenging dose of 2 Gy of X-rays delivered to the embryos at 10 hpf. PMID:26850927

CD4 T cell-mediated protection from lethal influenza: perforin and antibody-mediated mechanisms give a one-two punch.

PubMed

Brown, Deborah M; Dilzer, Allison M; Meents, Dana L; Swain, Susan L

2006-09-01

The mechanisms whereby CD4 T cells contribute to the protective response against lethal influenza infection remain poorly characterized. To define the role of CD4 cells in protection against a highly pathogenic strain of influenza, virus-specific TCR transgenic CD4 effectors were generated in vitro and transferred into mice given lethal influenza infection. Primed CD4 effectors conferred protection against lethal infection over a broad range of viral dose. The protection mediated by CD4 effectors did not require IFN-gamma or host T cells, but did result in increased anti-influenza Ab titers compared with untreated controls. Further studies indicated that CD4-mediated protection at high doses of influenza required B cells, and that passive transfer of anti-influenza immune serum was therapeutic in B cell-deficient mice, but only when CD4 effectors were present. Primed CD4 cells also acquired perforin (Pfn)-mediated cytolytic activity during effector generation, suggesting a second mechanism used by CD4 cells to confer protection. Pfn-deficient CD4 effectors were less able to promote survival in intact BALB/c mice and were unable to provide protection in B cell-deficient mice, indicating that Ab-independent protection by CD4 effectors requires Pfn. Therefore, CD4 effectors mediate protection to lethal influenza through at least two mechanisms: Pfn-mediated cytotoxicity early in the response promoted survival independently of Ab production, whereas CD4-driven B cell responses resulted in high titer Abs that neutralized remaining virus.

How Orthography Modulates Morphological Priming: Subliminal Kanji Activation in Japanese.

PubMed

Nakano, Yoko; Ikemoto, Yu; Jacob, Gunnar; Clahsen, Harald

2016-01-01

The current study investigates to what extent masked morphological priming is modulated by language-particular properties, specifically by its writing system. We present results from two masked priming experiments investigating the processing of complex Japanese words written in less common (moraic) scripts. In Experiment 1, participants performed lexical decisions on target verbs; these were preceded by primes which were either (i) a past-tense form of the same verb, (ii) a stem-related form with the epenthetic vowel -i, (iii) a semantically-related form, and (iv) a phonologically-related form. Significant priming effects were obtained for prime types (i), (ii), and (iii), but not for (iv). This pattern of results differs from previous findings on languages with alphabetic scripts, which found reliable masked priming effects for morphologically related prime/target pairs of type (i), but not for non-affixal and semantically-related primes of types (ii), and (iii). In Experiment 2, we measured priming effects for prime/target pairs which are neither morphologically, semantically, phonologically nor - as presented in their moraic scripts-orthographically related, but which-in their commonly written form-share the same kanji, which are logograms adopted from Chinese. The results showed a significant priming effect, with faster lexical-decision times for kanji-related prime/target pairs relative to unrelated ones. We conclude that affix-stripping is insufficient to account for masked morphological priming effects across languages, but that language-particular properties (in the case of Japanese, the writing system) affect the processing of (morphologically) complex words.

Goal-directed visual attention drives health goal priming: An eye-tracking experiment.

PubMed

van der Laan, Laura N; Papies, Esther K; Hooge, Ignace T C; Smeets, Paul A M

2017-01-01

Several lab and field experiments have shown that goal priming interventions can be highly effective in promoting healthy food choices. Less is known, however, about the mechanisms by which goal priming affects food choice. This experiment tested the hypothesis that goal priming affects food choices through changes in visual attention. Specifically, it was hypothesized that priming with the dieting goal steers attention toward goal-relevant, low energy food products, which, in turn, increases the likelihood of choosing these products. In this eye-tracking experiment, 125 participants chose between high and low energy food products in a realistic online supermarket task while their eye movements were recorded with an eye-tracker. One group was primed with a health and dieting goal, a second group was exposed to a control prime, and a third group was exposed to no prime at all. The health goal prime increased low energy food choices and decreased high energy food choices. Furthermore, the health goal prime resulted in proportionally longer total dwell times on low energy food products, and this effect mediated the goal priming effect on choices. The findings suggest that the effect of priming on consumer choice may originate from an increase in attention for prime-congruent items. This study supports the effectiveness of health goal priming interventions in promoting healthy eating and opens up directions for research on other behavioral interventions that steer attention toward healthy foods. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

How Orthography Modulates Morphological Priming: Subliminal Kanji Activation in Japanese

PubMed Central

Nakano, Yoko; Ikemoto, Yu; Jacob, Gunnar; Clahsen, Harald

2016-01-01

The current study investigates to what extent masked morphological priming is modulated by language-particular properties, specifically by its writing system. We present results from two masked priming experiments investigating the processing of complex Japanese words written in less common (moraic) scripts. In Experiment 1, participants performed lexical decisions on target verbs; these were preceded by primes which were either (i) a past-tense form of the same verb, (ii) a stem-related form with the epenthetic vowel -i, (iii) a semantically-related form, and (iv) a phonologically-related form. Significant priming effects were obtained for prime types (i), (ii), and (iii), but not for (iv). This pattern of results differs from previous findings on languages with alphabetic scripts, which found reliable masked priming effects for morphologically related prime/target pairs of type (i), but not for non-affixal and semantically-related primes of types (ii), and (iii). In Experiment 2, we measured priming effects for prime/target pairs which are neither morphologically, semantically, phonologically nor - as presented in their moraic scripts—orthographically related, but which—in their commonly written form—share the same kanji, which are logograms adopted from Chinese. The results showed a significant priming effect, with faster lexical-decision times for kanji-related prime/target pairs relative to unrelated ones. We conclude that affix-stripping is insufficient to account for masked morphological priming effects across languages, but that language-particular properties (in the case of Japanese, the writing system) affect the processing of (morphologically) complex words. PMID:27065895

HEND Maps of Epithermal Neutrons

NASA Technical Reports Server (NTRS)

2002-01-01

Observations by NASA's 2001 Mars Odyssey spacecraft show a global view of Mars in intermediate-energy, or epithermal, neutrons. These maps are based on data acquired by the high-energy neutron detector, one of the instruments in the gamma ray spectrometer suite. Soil enriched by hydrogen is indicated by the purple and deep blue colors on the maps, which show a low intensity of epithermal neutrons. Progressively smaller amounts of hydrogen are shown in the colors light blue, green, yellow and red. Hydrogen in the far north is hidden at this time beneath a layer of carbon dioxide frost (dry ice). These observations were acquired during the first two months of mapping operations. Contours of topography are superimposed on these maps for geographic reference.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. Investigators at Arizona State University in Tempe, the University of Arizona in Tucson, and NASA's Johnson Space Center, Houston, operate the science instruments. The gamma-ray spectrometer was provided by the University of Arizona in collaboration with the Russian Aviation and Space Agency, which provided the high-energy neutron detector, and the Los Alamos National Laboratories, New Mexico, which provided the neutron spectrometer. Lockheed Martin Astronautics, Denver, is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Water Mass Map from Neutron Spectrometer

NASA Technical Reports Server (NTRS)

2003-01-01

December 8, 2003

This map shows the estimated lower limit of the water content of the upper meter of Martian soil. The estimates are derived from the hydrogen abundance measured by the neutron spectrometer component of the gamma ray spectrometer suite on NASA's Mars Odyssey spacecraft.

The highest water-mass fractions, exceeding 30 percent to well over 60 percent, are in the polar regions, beyond about 60 degrees latitude north or south. Farther from the poles, significant concentrations are in the area bound in longitude by minus 10 degrees to 50 degrees and in latitude by 30 degrees south to 40 degrees north, and in an area to the south and west of Olympus Mons (30 degrees to 0 degrees south latitude and minus 135 degrees to 110 degrees longitude).

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the 2001 Mars Odyssey mission for the NASA Office of Space Science in Washington. Investigators at Arizona State University in Tempe, the University of Arizona in Tucson and NASA's Johnson Space Center, Houston, operate the science instruments. The gamma-ray spectrometer was provided by the University of Arizona in collaboration with the Russian Aviation and Space Agency, which provided the high-energy neutron detector, and the Los Alamos National Laboratories, New Mexico, which provided the neutron spectrometer. Lockheed Martin Space Systems, Denver, is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL.

The GW170817/GRB 170817A/AT 2017gfo Association: Some Implications for Physics and Astrophysics

NASA Astrophysics Data System (ADS)

Wang, Hao; Zhang, Fu-Wen; Wang, Yuan-Zhu; Shen, Zhao-Qiang; Liang, Yun-Feng; Li, Xiang; Liao, Neng-Hui; Jin, Zhi-Ping; Yuan, Qiang; Zou, Yuan-Chuan; Fan, Yi-Zhong; Wei, Da-Ming

2017-12-01

On 2017 August 17, a gravitational-wave event (GW170817) and an associated short gamma-ray burst (GRB 170817A) from a binary neutron star merger had been detected. The follow-up optical/infrared observations also identified the macronova/kilonova emission (AT 2017gfo). In this work, we discuss some implications of the remarkable GW170817/GRB 170817A/AT 2017gfo association. We show that the ∼1.7 s time delay between the gravitational-wave (GW) and GRB signals imposes very tight constraints on the superluminal movement of gravitational waves (i.e., the relative departure of GW velocity from the speed of light is ≤slant 4.3× {10}-16) or the possible violation of the weak equivalence principle (i.e., the difference of the gamma-ray and GW trajectories in the gravitational field of the galaxy and the local universe should be within a factor of ∼ 3.4× {10}-9). The so-called Dark Matter Emulators and a class of contender models for cosmic acceleration (“Covariant Galileon”) are ruled out as well. The successful identification of lanthanide elements in the macronova/kilonova spectrum also excludes the possibility that the progenitors of GRB 170817A are a binary strange star system. The high neutron star merger rate (inferred from both the local sGRB data and the gravitational-wave data) together with the significant ejected mass strongly suggest that such mergers are the prime sites of heavy r-process nucleosynthesis.

Part I: RNA hydrolysis catalyzed by imidazole compounds. Part II. Hydrophobic acceleration of reactions and mimics of thiamin-dependent enzymes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kool, E.T.

1988-01-01

Catalysts modeled after the active site groups of the enzyme Ribonuclease A were synthesized and tested for catalysis of the hydrolysis of poly(rU), using a quantitative assay. The most effective of all the catalysts is N,N{prime}-bis-imidazolylmethane, which gave a four-fold rate enhancement as compared to N-methyl-imidazole. The structure/activity relationships are discussed in light of the ribonuclease mechanism. Also examined were reactions catalyzed by the coenzyme thiamine. In an investigation of the effects of restricting conformational freedom, a thiazolium salt was attached in two positions to {beta}-cyclodextrin. Since the catalyst gave about the same rate for tritium exchange from benzaldehyde asmore » singly-attached catalysts, we surmise that any rate enhancement due to the restriction of bond rotations has been lost by forcing the structure into less productive conformations. The benzoin condensation catalyzed by cyanide was also investigated. The reaction was shown to be faster in water than in most organic solvents. Kinetic salt effects and the effects of added {beta}- and {gamma}-cyclodextrin were measured in water; salting-out ions and {gamma}-cyclodextrin increase the rate, while salting-in ions and {beta}-cyclodextrin decrease it. Negative salt effects were observed in formamide, ethylene glycol, and DMSO. All these media effects are discussed in relation to the compact, hydrophobic transition state for the reaction.« less

When Less is More: Feedback, Priming, and the Pseudoword Superiority Effect

PubMed Central

Massol, Stéphanie; Midgley, Katherine J.; Holcomb, Phillip J.; Grainger, Jonathan

2011-01-01

The present study combined masked priming with electrophysiological recordings to investigate orthographic priming effects with nonword targets. Targets were pronounceable nonwords (e.g., STRENG) or consonant strings (e.g., STRBNG), that both differed from a real word by a single letter substitution (STRONG). Targets were preceded by related primes that could be the same as the target (e.g., streng – STRENG, strbng-STRBNG) or the real word neighbor of the target (e.g., strong – STRENG, strong-STRBNG). Independently of priming, pronounceable nonwords were associated with larger negativities than consonant strings, starting at 290 ms post-target onset. Overall, priming effects were stronger and more long-lasting with pronounceable nonwords than consonant strings. However, consonant string targets showed an early effect of word neighbor priming in the absence of an effect of repetition priming, whereas pronounceable nonwords showed both repetition and word neighbor priming effects in the same time window. This pattern of priming effects is taken as evidence for feedback from whole-word orthographic representations activated by the prime stimulus that influences bottom-up processing of prelexical representations during target processing. PMID:21354110

Transposed-letter priming of prelexical orthographic representations.

PubMed

Kinoshita, Sachiko; Norris, Dennis

2009-01-01

A prime generated by transposing two internal letters (e.g., jugde) produces strong priming of the original word (judge). In lexical decision, this transposed-letter (TL) priming effect is generally weak or absent for nonword targets; thus, it is unclear whether the origin of this effect is lexical or prelexical. The authors describe the Bayesian Reader theory of masked priming (D. Norris & S. Kinoshita, 2008), which explains why nonwords do not show priming in lexical decision but why they do in the cross-case same-different task. This analysis is followed by 3 experiments that show that priming in this task is not based on low-level perceptual similarity between the prime and target, or on phonology, to make the case that priming is based on prelexical orthographic representation. The authors then use this task to demonstrate equivalent TL priming effects for nonwords and words. The results are interpreted as the first reliable evidence based on the masked priming procedure that letter position is not coded absolutely within the prelexical, orthographic representation. The implications of the results for current letter position coding schemes are discussed.

Mechanisms of masked evaluative priming: task sets modulate behavioral and electrophysiological priming for picture and words differentially.

PubMed

Kiefer, Markus; Liegel, Nathalie; Zovko, Monika; Wentura, Dirk

2017-04-01

Research with the evaluative priming paradigm has shown that affective evaluation processes reliably influence cognition and behavior, even when triggered outside awareness. However, the precise mechanisms underlying such subliminal evaluative priming effects, response activation vs semantic processing, are matter of a debate. In this study, we determined the relative contribution of semantic processing and response activation to masked evaluative priming with pictures and words. To this end, we investigated the modulation of masked pictorial vs verbal priming by previously activated perceptual vs semantic task sets and assessed the electrophysiological correlates of priming using event-related potential (ERP) recordings. Behavioral and electrophysiological effects showed a differential modulation of pictorial and verbal subliminal priming by previously activated task sets: Pictorial priming was only observed during the perceptual but not during the semantic task set. Verbal priming, in contrast, was found when either task set was activated. Furthermore, only verbal priming was associated with a modulation of the N400 ERP component, an index of semantic processing, whereas a priming-related modulation of earlier ERPs, indexing visuo-motor S-R activation, was found for both picture and words. The results thus demonstrate that different neuro-cognitive processes contribute to unconscious evaluative priming depending on the stimulus format. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Structural Priming and Frequency Effects Interact in Chinese Sentence Comprehension

PubMed Central

Wei, Hang; Dong, Yanping; Boland, Julie E.; Yuan, Fang

2016-01-01

Previous research in several European languages has shown that the language processing system is sensitive to both structural frequency and structural priming effects. However, it is currently not clear whether these two types of effects interact during online sentence comprehension, especially for languages that do not have morphological markings. To explore this issue, the present study investigated the possible interplay between structural priming and frequency effects for sentences containing the Chinese ambiguous construction V NP1 de NP2 in a self-paced reading experiment. The sentences were disambiguated to either the more frequent/preferred NP structure or the less frequent VP structure. Each target sentence was preceded by a prime sentence of three possible types: NP primes, VP primes, and neutral primes. When the ambiguous construction V NP1 de NP2 was disambiguated to the dispreferred VP structure, participants experienced more processing difficulty following an NP prime relative to following a VP prime or a neutral baseline. When the ambiguity was resolved to the preferred NP structure, prime type had no effect. These results suggest that structural priming in comprehension is modulated by the baseline frequency of alternative structures, with the less frequent structure being more subject to structural priming effects. These results are discussed in the context of the error-based, implicit learning account of structural priming. PMID:26869954

Study of in-medium {\\eta }^{\\prime} properties in the (γ, \\eta ^{\\prime} p) reaction on nuclei

NASA Astrophysics Data System (ADS)

Paryev, E. Ya

2016-01-01

We study the near-threshold photoproduction of {η }\\prime mesons from nuclei in coincidence with forward going protons in the kinematical conditions of the Crystal Barrel/TAPS experiment, recently performed at ELSA. The calculations have been performed within a collision model based on the nuclear spectral function. The model accounts for both the primary γ p\\to η \\prime p process and the two-step intermediate nucleon rescattering processes as well as the effect of the nuclear η \\prime mean-field potential. We calculate the exclusive η \\prime kinetic energy distributions for the 12C(γ, η \\prime p) reaction for different scenarios of η \\prime in-medium modification. We find that the considered two-step rescattering mechanism plays an insignificant role in η \\prime p photoproduction off the carbon target. We also demonstrate that the calculated η \\prime kinetic energy distributions in primary photon-proton η \\prime p production reveal strong sensitivity to the depth of the real η \\prime potential at normal nuclear matter density (or to the η \\prime in-medium mass shift) in the studied incident photon energy regime. Therefore, such observables may be useful to help determine the above η \\prime in-medium renormalization from the comparison of the results of our calculations with the data from the CBELSA/TAPS experiment. In addition, we show that these distributions are also strongly influenced by the momentum-dependent optical potential, which the outgoing participant proton feels inside the carbon nucleus. This potential should be taken into account in the analysis of these data with the aim to obtain information on the η \\prime modification in cold nuclear matter.

Comparing different kinds of words and word-word relations to test an habituation model of priming.

PubMed

Rieth, Cory A; Huber, David E

2017-06-01

Huber and O'Reilly (2003) proposed that neural habituation exists to solve a temporal parsing problem, minimizing blending between one word and the next when words are visually presented in rapid succession. They developed a neural dynamics habituation model, explaining the finding that short duration primes produce positive priming whereas long duration primes produce negative repetition priming. The model contains three layers of processing, including a visual input layer, an orthographic layer, and a lexical-semantic layer. The predicted effect of prime duration depends both on this assumed representational hierarchy and the assumption that synaptic depression underlies habituation. The current study tested these assumptions by comparing different kinds of words (e.g., words versus non-words) and different kinds of word-word relations (e.g., associative versus repetition). For each experiment, the predictions of the original model were compared to an alternative model with different representational assumptions. Experiment 1 confirmed the prediction that non-words and inverted words require longer prime durations to eliminate positive repetition priming (i.e., a slower transition from positive to negative priming). Experiment 2 confirmed the prediction that associative priming increases and then decreases with increasing prime duration, but remains positive even with long duration primes. Experiment 3 replicated the effects of repetition and associative priming using a within-subjects design and combined these effects by examining target words that were expected to repeat (e.g., viewing the target word 'BACK' after the prime phrase 'back to'). These results support the originally assumed representational hierarchy and more generally the role of habituation in temporal parsing and priming. Copyright © 2017 Elsevier Inc. All rights reserved.

Improved tolerance to post-anthesis drought stress by pre-drought priming at vegetative stages in drought-tolerant and -sensitive wheat cultivars.

PubMed

Abid, Muhammad; Tian, Zhongwei; Ata-Ul-Karim, Syed Tahir; Liu, Yang; Cui, Yakun; Zahoor, Rizwan; Jiang, Dong; Dai, Tingbo

2016-09-01

Wheat crop endures a considerable penalty of yield reduction to escape the drought events during post-anthesis period. Drought priming under a pre-drought stress can enhance the crop potential to tolerate the subsequent drought stress by triggering a faster and stronger defense mechanism. Towards these understandings, a set of controlled moderate drought stress at 55-60% field capacity (FC) was developed to prime the plants of two wheat cultivars namely Luhan-7 (drought tolerant) and Yangmai-16 (drought sensitive) during tillering (Feekes 2 stage) and jointing (Feekes 6 stage), respectively. The comparative response of primed and non-primed plants, cultivars and priming stages was evaluated by applying a subsequent severe drought stress at 7 days after anthesis. The results showed that primed plants of both cultivars showed higher potential to tolerate the post-anthesis drought stress through improved leaf water potential, more chlorophyll, and ribulose-1, 5-bisphosphate carboxylase/oxygenase contents, enhanced photosynthesis, better photoprotection and efficient enzymatic antioxidant system leading to less yield reductions. The primed plants of Luhan-7 showed higher capability to adapt the drought stress events than Yangmai-16. The positive effects of drought priming to sustain higher grain yield were pronounced in plants primed at tillering than those primed at jointing. In consequence, upregulated functioning of photosynthetic apparatus and efficient enzymatic antioxidant activities in primed plants indicated their superior potential to alleviate a subsequently occurring drought stress, which contributed to lower yield reductions than non-primed plants. However, genotypic and priming stages differences in response to drought stress also contributed to affect the capability of primed plants to tolerate the post-anthesis drought stress conditions in wheat. Copyright © 2016. Published by Elsevier Masson SAS.

Subliminal semantic priming in speech.

PubMed

Daltrozzo, Jérôme; Signoret, Carine; Tillmann, Barbara; Perrin, Fabien

2011-01-01

Numerous studies have reported subliminal repetition and semantic priming in the visual modality. We transferred this paradigm to the auditory modality. Prime awareness was manipulated by a reduction of sound intensity level. Uncategorized prime words (according to a post-test) were followed by semantically related, unrelated, or repeated target words (presented without intensity reduction) and participants performed a lexical decision task (LDT). Participants with slower reaction times in the LDT showed semantic priming (faster reaction times for semantically related compared to unrelated targets) and negative repetition priming (slower reaction times for repeated compared to semantically related targets). This is the first report of semantic priming in the auditory modality without conscious categorization of the prime.

Subliminal Semantic Priming in Speech

PubMed Central

Tillmann, Barbara; Perrin, Fabien

2011-01-01

Numerous studies have reported subliminal repetition and semantic priming in the visual modality. We transferred this paradigm to the auditory modality. Prime awareness was manipulated by a reduction of sound intensity level. Uncategorized prime words (according to a post-test) were followed by semantically related, unrelated, or repeated target words (presented without intensity reduction) and participants performed a lexical decision task (LDT). Participants with slower reaction times in the LDT showed semantic priming (faster reaction times for semantically related compared to unrelated targets) and negative repetition priming (slower reaction times for repeated compared to semantically related targets). This is the first report of semantic priming in the auditory modality without conscious categorization of the prime. PMID:21655277

Synthesis of macrocyclic polyaminocarboxylates and their use for preparing stable radiometal antibody immunoconjugates for therapy, SPECT and PET imaging

DOEpatents

Mease, R.C.; Mausner, L.F.; Srivastava, S.C.

1995-06-27

A simple method for the synthesis of 1,4,7,10-tetraazacyclododecane N,N{prime}N{double_prime},N{prime}{double_prime}-tetraacetic acid and 1,4,8,11-tetraazacyclotetradecane N,N{prime},N{double_prime},N{prime}{double_prime}-tetraacetic acid involves cyanomethylating 1,4,7,10-tetraazacyclododecane or 1,4,8,11-tetraazacyclotetradecane to form a tetranitrile and hydrolyzing the tetranitrile. These macrocyclic compounds are functionalized through one of the carboxylates and then conjugated to various biological molecules including monoclonal antibodies. The resulting conjugated molecules are labeled with radiometals for SPECT and PET imaging and for radiotherapy. 4 figs.

Reading a standing wave: figure-ground-alternation masking of primes in evaluative priming.

PubMed

Bermeitinger, Christina; Kuhlmann, Michael; Wentura, Dirk

2012-09-01

We propose a new masking technique for masking word stimuli. Drawing on the phenomena of metacontrast and paracontrast, we alternately presented two prime displays of the same word with the background color in one display matching the font color in the other display and vice versa. The sequence of twenty alterations (spanning approx. 267 ms) was sandwich-masked by structure masks. Using this masking technique, we conducted evaluative priming experiments with positive and negative target and prime words. Significant priming effects were found - for primes and targets drawn from the same as well as from different word sets. Priming effects were independent of prime discrimination performance in direct tests and they were still significant after the sample was restricted to those participants who showed random responding in the direct test. Copyright © 2012 Elsevier Inc. All rights reserved.

An Electrophysiological Investigation of Early Effects of Masked Morphological Priming

ERIC Educational Resources Information Center

Morris, Joanna; Grainger, Jonathan; Holcomb, Phillip J.

2008-01-01

This experiment examined event-related responses to targets preceded by semantically transparent morphologically related primes (e.g., farmer-farm), semantically opaque primes with an apparent morphological relation (corner-corn), and orthographically, but not morphologically, related primes (scandal-scan) using the masked priming technique…

Complex architecture of primes and natural numbers.

PubMed

García-Pérez, Guillermo; Serrano, M Ángeles; Boguñá, Marián

2014-08-01

Natural numbers can be divided in two nonoverlapping infinite sets, primes and composites, with composites factorizing into primes. Despite their apparent simplicity, the elucidation of the architecture of natural numbers with primes as building blocks remains elusive. Here, we propose a new approach to decoding the architecture of natural numbers based on complex networks and stochastic processes theory. We introduce a parameter-free non-Markovian dynamical model that naturally generates random primes and their relation with composite numbers with remarkable accuracy. Our model satisfies the prime number theorem as an emerging property and a refined version of Cramér's conjecture about the statistics of gaps between consecutive primes that seems closer to reality than the original Cramér's version. Regarding composites, the model helps us to derive the prime factors counting function, giving the probability of distinct prime factors for any integer. Probabilistic models like ours can help to get deeper insights about primes and the complex architecture of natural numbers.

Subliminal or not? Comparing null-hypothesis and Bayesian methods for testing subliminal priming.

PubMed

Sand, Anders; Nilsson, Mats E

2016-08-01

A difficulty for reports of subliminal priming is demonstrating that participants who actually perceived the prime are not driving the priming effects. There are two conventional methods for testing this. One is to test whether a direct measure of stimulus perception is not significantly above chance on a group level. The other is to use regression to test if an indirect measure of stimulus processing is significantly above zero when the direct measure is at chance. Here we simulated samples in which we assumed that only participants who perceived the primes were primed by it. Conventional analyses applied to these samples had a very large error rate of falsely supporting subliminal priming. Calculating a Bayes factor for the samples very seldom falsely supported subliminal priming. We conclude that conventional tests are not reliable diagnostics of subliminal priming. Instead, we recommend that experimenters calculate a Bayes factor when investigating subliminal priming. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Cathode Priming vs. RF Priming for Relativistic Magnetrons

NASA Astrophysics Data System (ADS)

White, W. M.; Spencer, T. A.; Price, D.

2005-10-01

Magnetron start-oscillation time, pulsewidth and pi-mode locking are experimentally compared for RF priming versus cathode priming on the Michigan-Titan relativistic magnetron (-300 kV, 2-10 kA, 300-500 ns). Cathode priming [1, 2] is an innovative technique first demonstrated experimentally at UM. In this technique, the cathode is fabricated with N/2 emitting strips or N/2-separate cathodes (for an N-cavity magnetron), which generate the desired number of spokes for pi-mode. Cathode priming yields 13% faster startup with more reproducible pi-mode oscillation. Radio Frequency (RF) priming is investigated as the baseline priming technique for magnetrons. The external priming source is a 100kW, 3μs pulsewidth magnetron on loan from AFRL. RF priming reduced startup delay by 15% and increased pulsewidth by 9%. [1] M.C. Jones, V.B. Neculaes, R.M. Gilgenbach, W.M. White, M.R. Lopez, Y.Y. Lau, T.A. Spencer, and D. Price, Rev. Sci. Inst., 75, 2976 (2004) [2] M.C. Jones, Doctoral Dissertation, University of Michigan, 2005

Mechanisms of masked priming: a meta-analysis.

PubMed

Van den Bussche, Eva; Van den Noortgate, Wim; Reynvoet, Bert

2009-05-01

The extent to which unconscious information can influence behavior has been a topic of considerable debate throughout the history of psychology. A frequently used method for studying subliminal processing is the masked priming paradigm. The authors focused on studies in which this paradigm was used. Their aim was twofold: first, to assess the magnitude of subliminal priming across the literature and to determine whether subliminal primes are processed semantically, and second, to examine potential moderators of priming effects. The authors found significant priming in their analyses, indicating that unconsciously presented information can influence behavior. Furthermore, priming was observed under circumstances in which a nonsemantic interpretation could not fully explain the effects, suggesting that subliminally presented information can be processed semantically. Nonetheless, the nonsemantic processing of primes is enhanced and priming effects are boosted when the experimental context allows the formation of automatic stimulus-response mappings. This quantitative review also revealed several moderators that influence the strength of priming. (PsycINFO Database Record (c) 2009 APA, all rights reserved).

Activating situation schemas: the effects of multiple thematic roles on related verbs in a continuous priming paradigm.

PubMed

Herlofsky, Stacey M; Edmonds, Lisa A

2013-02-01

Extensive evidence has shown that presentation of a word (target) following a related word (prime) results in faster reaction times compared to unrelated words. Two primes preceding a target have been used to examine the effects of multiple influences on a target. Several studies have observed greater, or additive, priming effects of multiple related primes compared to single related primes. The present study aims to eliminate attentional factors that may have contributed to findings in previous studies that used explicitly presented primes and targets. Thus, a continuous priming paradigm where targets are unknown to participants is used with noun-noun-verb triads filling agent, patient, and action roles in situation schemas (tourist, car, rent). Results replicate priming of single nouns preceding related verbs but do not suggest an additive effect for two nouns versus one. The absence of additive priming suggests that attentional processes may have been a factor in previous research.

Is semantic priming (ir)rational? Insights from the speeded word fragment completion task.

PubMed

Heyman, Tom; Hutchison, Keith A; Storms, Gert

2016-10-01

Semantic priming, the phenomenon that a target is recognized faster if it is preceded by a semantically related prime, is a well-established effect. However, the mechanisms producing semantic priming are subject of debate. Several theories assume that the underlying processes are controllable and tuned to prime utility. In contrast, purely automatic processes, like automatic spreading activation, should be independent of the prime's usefulness. The present study sought to disentangle both accounts by creating a situation where prime processing is actually detrimental. Specifically, participants were asked to quickly complete word fragments with either the letter a or e (e.g., sh_ve to be completed as shave). Critical fragments were preceded by a prime that was either related (e.g., push) or unrelated (write) to a prohibited completion of the target (e.g., shove). In 2 experiments, we found a significant inhibitory priming effect, which is inconsistent with purely "rational" explanations of semantic priming. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Does achievement motivation mediate the semantic achievement priming effect?

PubMed

Engeser, Stefan; Baumann, Nicola

2014-10-01

The aim of our research was to understand the processes of the prime-to-behavior effects with semantic achievement primes. We extended existing models with a perspective from achievement motivation theory and additionally used achievement primes embedded in the running text of excerpts of school textbooks to simulate a more natural priming condition. Specifically, we proposed that achievement primes affect implicit achievement motivation and conducted pilot experiments and 3 main experiments to explore this proposition. We found no reliable positive effect of achievement primes on implicit achievement motivation. In light of these findings, we tested whether explicit (instead of implicit) achievement motivation is affected by achievement primes and found this to be the case. In the final experiment, we found support for the assumption that higher explicit achievement motivation implies that achievement priming affects the outcome expectations. The implications of the results are discussed, and we conclude that primes affect achievement behavior by heightening explicit achievement motivation and outcome expectancies.

The temporal dynamics of masked repetition picture priming effects: manipulations of stimulus-onset asynchrony (SOA) and prime duration.

PubMed

Eddy, Marianna D; Holcomb, Phillip J

2010-06-22

The current study used event-related potentials (ERPs) and masked repetition priming to examine the time-course of picture processing. We manipulated the stimulus-onset asynchrony (110 ms, 230 ms, 350 ms, and 470 ms) between repeated and unrepeated prime-target pairs while holding the prime duration constant (50 ms) (Experiment 1) as well as the prime durations (30 ms, 50 ms, 70 ms, and 90 ms) (Experiment 2) with a constant SOA of 110 ms in a masked repetition priming paradigm with pictures. The aim of this study was to further elucidate the mechanisms underlying previously observed ERP components in masked priming with pictures. We found that both the N/P190 and N400 are modulated by changes in prime duration and SOA, however, it appears that longer prime exposure rather than a longer SOA leads to more in-depth processing as indexed by larger N400 effects. (c) 2010 Elsevier B.V. All rights reserved.

Lexical precision in skilled readers: Individual differences in masked neighbor priming.

PubMed

Andrews, Sally; Hersch, Jolyn

2010-05-01

Two experiments investigated the relationship between masked form priming and individual differences in reading and spelling proficiency among university students. Experiment 1 assessed neighbor priming for 4-letter word targets from high- and low-density neighborhoods in 97 university students. The overall results replicated previous evidence of facilitatory neighborhood priming only for low-neighborhood words. However, analyses including measures of reading and spelling proficiency as covariates revealed that better spellers showed inhibitory priming for high-neighborhood words, while poorer spellers showed facilitatory priming. Experiment 2, with 123 participants, replicated the finding of stronger inhibitory neighbor priming in better spellers using 5-letter words and distinguished facilitatory and inhibitory components of priming by comparing neighbor primes with ambiguous and unambiguous partial-word primes (e.g., crow#, cr#wd, crown CROWD). The results indicate that spelling ability is selectively associated with inhibitory effects of lexical competition. The implications for theories of visual word recognition and the lexical quality hypothesis of reading skill are discussed.

Event Structure Influences Language Production: Evidence from Structural Priming in Motion Event Description

PubMed Central

Bunger, Ann; Papafragou, Anna; Trueswell, John C.

2013-01-01

This priming study investigates the role of conceptual structure during language production, probing whether English speakers are sensitive to the structure of the event encoded by a prime sentence. In two experiments, participants read prime sentences aloud before describing motion events. Primes differed in 1) syntactic frame, 2) degree of lexical and conceptual overlap with target events, and 3) distribution of event components within frames. Results demonstrate that conceptual overlap between primes and targets led to priming of (a) the information that speakers chose to include in their descriptions of target events, (b) the way that information was mapped to linguistic elements, and (c) the syntactic structures that were built to communicate that information. When there was no conceptual overlap between primes and targets, priming was not successful. We conclude that conceptual structure is a level of representation activated during priming, and that it has implications for both Message Planning and Linguistic Formulation. PMID:24072953

Is masked priming modulated by memory load? A test of the automaticity of masked identity priming in lexical decision.

PubMed

Perea, Manuel; Marcet, Ana; Lozano, Mario; Gomez, Pablo

2018-05-29

One of the key assumptions of the masked priming lexical decision task (LDT) is that primes are processed without requiring attentional resources. Here, we tested this assumption by presenting a dual-task manipulation to increase memory load and measure the change in masked identity priming on the targets in the LDT. If masked priming does not require attentional resources, increased memory load should have no influence on the magnitude of the observed identity priming effects. We conducted two LDT experiments, using a within-subjects design, to investigate the effect of memory load (via a concurrent matching task Experiment 1 and a concurrent search task in Experiment 2) on masked identity priming. Results showed that the magnitude of masked identity priming on word targets was remarkably similar under high and low memory load. Thus, these experiments provide empirical evidence for the automaticity assumption of masked identity priming in the LDT.

The effect of unimodal affective priming on dichotic emotion recognition.

PubMed

Voyer, Daniel; Myles, Daniel

2017-11-15

The present report concerns two experiments extending to unimodal priming the cross-modal priming effects observed with auditory emotions by Harding and Voyer [(2016). Laterality effects in cross-modal affective priming. Laterality: Asymmetries of Body, Brain and Cognition, 21, 585-605]. Experiment 1 used binaural targets to establish the presence of the priming effect and Experiment 2 used dichotically presented targets to examine auditory asymmetries. In Experiment 1, 82 university students completed a task in which binaural targets consisting of one of 4 English words inflected in one of 4 emotional tones were preceded by binaural primes consisting of one of 4 Mandarin words pronounced in the same (congruent) or different (incongruent) emotional tones. Trials where the prime emotion was congruent with the target emotion showed faster responses and higher accuracy in identifying the target emotion. In Experiment 2, 60 undergraduate students participated and the target was presented dichotically instead of binaurally. Primes congruent with the left ear produced a large left ear advantage, whereas right congruent primes produced a right ear advantage. These results indicate that unimodal priming produces stronger effects than those observed under cross-modal priming. The findings suggest that priming should likely be considered a strong top-down influence on laterality effects.

Replicable effects of primes on human behavior.

PubMed

Payne, B Keith; Brown-Iannuzzi, Jazmin L; Loersch, Chris

2016-10-01

[Correction Notice: An Erratum for this article was reported online in Journal of Experimental Psychology: General on Oct 31 2016 (see record 2016-52334-001). ] The effect of primes (i.e., incidental cues) on human behavior has become controversial. Early studies reported counterintuitive findings, suggesting that primes can shape a wide range of human behaviors. Recently, several studies failed to replicate some earlier priming results, raising doubts about the reliability of those effects. We present a within-subjects procedure for priming behavior, in which participants decide whether to bet or pass on each trial of a gambling game. We report 6 replications (N = 988) showing that primes consistently affected gambling decisions when the decision was uncertain. Decisions were influenced by primes presented visibly, with a warning to ignore the primes (Experiments 1 through 3) and with subliminally presented masked primes (Experiment 4). Using a process dissociation procedure, we found evidence that primes influenced responses through both automatic and controlled processes (Experiments 5 and 6). Results provide evidence that primes can reliably affect behavior, under at least some conditions, without intention. The findings suggest that the psychological question of whether behavior priming effects are real should be separated from methodological issues affecting how easily particular experimental designs will replicate. PsycINFO Database Record (c) 2016 APA, all rights reserved

Gamma-ray Bursts May Originate in Star-Forming Regions

NASA Astrophysics Data System (ADS)

2001-04-01

New findings from two X-ray satellites suggest that gamma-ray bursts, some of the most intense blasts in the universe, may be created in the same area where stars are born. Dr. Luigi Piro of the Consiglio Nazionale delle Ricerche (CNR) in Rome, Italy, presented data from NASA's Chandra X-ray Observatory and the Italian-Dutch ASI BeppoSAX observatory today at the Gamma Ray 2001 conference in Baltimore, MD. "We know that when a gamma-ray burst explodes, it produces a blast of material called a fireball, which expands at relativistic speeds like a rapidly inflating bubble," said Piro, who works within CNR's Istituto di Astrofisica Spaziale. "Our team found evidence that the blast wave caused by the fireball brakes against a wall of very dense gas, which we believe is the crowded region where stars form." Several theories exist about what causes gamma-ray bursts. Among more popular theories are that gamma-ray bursts come from various combinations of merging neutron stars and black holes, or, from the explosion of massive stars, called hypernovae. "Because gamma-ray bursts are going off in extremely distant galaxies, it is difficult to 'see' the regions that harbor them," said Piro. "We can only gather circumstantial evidence as to where and how they form." Piro's observations support the hypernova model. Scientists believe that within dense star-forming regions, the massive star required for a hypernova explosion evolves extremely rapidly. On astronomical time scales, the supermassive star would evolve over the course of only about one million years. Thus, the hypernova explosion may occur in the same stellar environment that originally produced the massive star itself, and perhaps may trigger even more star formation. The hint that gamma-ray bursts can occur in dense media came during a Chandra observation of an afterglow that occurred on September 26, 2000. Prof. Gordon Garmire of Pennsylvania State University, University Park, PA, found X-ray emission to be greater than that expected by the standard scenario of a fireball in a low-density medium - an important clue that the explosion occurred in a dense region. Next, on February 22, 2001, Piro said that Chandra observations of the burst's afterglow, one of the brightest bursts ever observed by BeppoSAX, provided evidence of a fireball expanding in a very dense gas. These recent results supported data from four other gamma-ray bursts observed by BeppoSAX and Chandra (GRB970508, GRB990705, GRB991216, and GRB000214). In these bursts, Piro and his team found evidence indicating that the burst had encountered an extremely dense gas. The properties of this gas suggest that it originated from a very massive progenitor before it exploded as a gamma-ray burst. A key element in the success of these observations has been the perfect timing and liaison between the two satellites, Chandra and BeppoSAX, according to Piro. Piro is the Mission Scientist for BeppoSAX, the instrument that first detected X-ray afterglows from gamma-ray bursts. Currently, astronomers are not usually notified about gamma-ray bursts until an hour or so after they occur. These bursts last only for a few milliseconds to about a minute, although their afterglow can linger in X-ray and optical light for days or weeks. The HETE-2 satellite, launched in October 2000, and Swift, scheduled for a 2003 launch, will provide nearly instant notification of bursts in action, providing satellites such as Chandra a better opportunity to study the afterglow phenomenon in depth. The ACIS X-ray camera was developed for NASA by Penn State and the Massachusetts Institute of Technology. The High Energy Transmission Grating Spectrometer was built by MIT. NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program. TRW, Inc., Redondo Beach, California, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA. Images associated with this release are available on the World Wide Web at: http://chandra.harvard.edu AND http://chandra.nasa.gov

ESA presents INTEGRAL, its space observatory for Gamma-ray astronomy

NASA Astrophysics Data System (ADS)

1998-09-01

A unique opportunity for journalists and cameramen to view INTEGRAL will be provided at ESA/ESTEC, Noordwijk, the Netherlands on Tuesday 22 September. On show will be the full-size structural thermal model which is now beeing examined in ESA's test centre. Following introductions to the project, the INTEGRAL spacecraft can be seen, filmed and photographed in its special clean room environment.. Media representatives wishing to participate in the visit to ESA's test centre and the presentation of INTEGRAL are kindly requested to return by fax the attached registration form to ESA Public relations, Tel. +33 (0) 1.53.69.71.55 - Fax. +33 (0) 1.53.69.76.90. For details please see the attached programme Gamma-ray astronomy - why ? Gamma-rays cannot be detected from the ground since the earth's atmosphere shields us from high energetic radiation. Only space technology has made gamma-astronomy possible. To avoid background radiation effects INTEGRAL will spend most of its time in the orbit outside earth's radiation belts above an altitude of 40'000 km. Gamma-rays are the highest energy form of electromagnetic radiation. Therefore gamma-ray astronomy explores the most energetic phenomena occurring in nature and addresses some of the most fundamental problems in physics. We know for instance that most of the chemical elements in our bodies come from long-dead stars. But how were these elements formed? INTEGRAL will register gamma-ray evidence of element-making. Gamma-rays also appear when matter squirms in the intense gravity of collapsed stars or black holes. One of the most important scientific objectives of INTEGRAL is to study such compact objects as neutron stars or black holes. Besides stellar black holes there may exist much bigger specimens of these extremely dense objects. Most astronomers believe that in the heart of our Milky Way as in the centre of other galaxies there may lurk giant black holes. INTEGRAL will have to find evidence of these exotic objects. Even more strange than the energetic radiation coming from the centre of distant galaxies are flashes of extremely powerful radiation that suddenly appear somewhere on the gamma-sky and disappear again after a short time. These gamma-bursts seem to be the biggest observed explosions in the Universe. But nobody knows their source. Integral will help to solve this long-standing mystery. ESA, the pioneer in gamma-ray astronomy The satellite as it can now be seen at ESA's test centre is five meters high and weighs more than four tonnes. Two main instruments observe the gamma-rays. An imager will give the sharpest gamma-ray images. It is provided by a consortium led by an Italian scientist. Gamma-rays ignore lenses and mirror, so INTEGRAL makes its images with so-called coded-masks. A coded-mask telescope is basically a pinhole camera, but with a larger aperture, i.e. many pinholes. A spectrometer will gauge gamma-ray energies extremely precisely. It is developed by a team of scientists under joint French-German leadership and will be a 100 times more sensitive than the previous high spectral resolution space instrument. It is made of a high-purity Germanium detector that has to be cooled down to minus 188 degree Celsius. These two gamma-ray-instruments are supported by two monitor instruments that play a crucial role in the detection and identification of the gamma-ray sources. An X-ray monitor developed in Denmark will observe X-rays, still powerful but less energetic than gamma-rays. An optical telescope provided by Spain will observe the visible light emitted by the energetic objects. Switzerland will host the Integral Science Data Centre which will preprocess and distribute the scientific data. The mission is conceived as an observatory led by ESA with Russia contributing the launcher and NASA providing tracking support with its Deep Space Network. Alenia Aerospazio in Turin, Italy is ESA's prime contractor for building INTEGRAL. Launch by a Russian Proton rocket from Baikonur is actually scheduled for 2001. ESA pioneered gamma-ray astronomy in space with its COS-B satellite (1975). Russia's Granat (1989) and NASA's Compton GRO (1991) followed. But INTEGRAL will be better still. With this mission ESA will further strengthen its lead in gamma-astronomy. Principal Investigators : Imager : Pietro Ubertini (IAS, Frascati, Italy) Spectrometer : Gilbert Vedrenne (CESR, Toulouse/France) Volker Schoenfelder (MPE, Garching/.Germany) X-Ray monitor : Niels Lund (DSRI, Copenhagen/Denmark) Optical Monitoring Camera : Alvaro Gimenez (INTA, Madrid/Spain) Integral Science Data Center : Thierry Courvoisier (Genova Observatory, Switzerland) For further information, please contact : ESA Public Relations Division Tel: +33(0)1.53.69.71.55 Fax: +33(0)1.53.69.76.90 INTEGRAL MEDIA DAY Tuesday 22 September 1998 Newton Conference Centre ESTEC, Noordwijk, Keplerlaan 1 (The Netherlands) Programme 10:30 . Arrival and Registration in the Newton Conference Centre 10:45. Welcome and introduction by David Dale, Director of ESTEC 10:50 The Scientific Challenge : the mission of INTEGRAL, by Chistoph Winkler, INTEGRAL Project Scientist 11:10 The Technical Challenge : the INTEGRAL spacecraft, by Kai Clausen, INTEGRAL Project Manager 11:30 The Industrial Challenge by A. Simeone, Programme Director at Aleniaspazio 11:45 Question/Answer session 12:00 Visit to INTEGRAL spacecraft ; photo and film opportunities, incl. Interview opportunities with speakers 13:00 Informal buffet lunch in Foyer of Conference Centre Newton 14:30 End of event

Semantic Priming for Coordinate Distant Concepts in Alzheimer's Disease Patients

ERIC Educational Resources Information Center

Perri, R.; Zannino, G. D.; Caltagirone, C.; Carlesimo, G. A.

2011-01-01

Semantic priming paradigms have been used to investigate semantic knowledge in patients with Alzheimer's disease (AD). While priming effects produced by prime-target pairs with associative relatedness reflect processes at both lexical and semantic levels, priming effects produced by words that are semantically related but not associated should…

Masked Inhibitory Priming in English: Evidence for Lexical Inhibition

ERIC Educational Resources Information Center

Davis, Colin J.; Lupker, Stephen J.

2006-01-01

Predictions derived from the interactive activation (IA) model were tested in 3 experiments using the masked priming technique in the lexical decision task. Experiment 1 showed a strong effect of prime lexicality: Classifications of target words were facilitated by orthographically related nonword primes (relative to unrelated nonword primes) but…

Test Sequence Priming in Recognition Memory

ERIC Educational Resources Information Center

Johns, Elizabeth E.; Mewhort, D. J. K.

2009-01-01

The authors examined priming within the test sequence in 3 recognition memory experiments. A probe primed its successor whenever both probes shared a feature with the same studied item ("interjacent priming"), indicating that the study item like the probe is central to the decision. Interjacent priming occurred even when the 2 probes did…

Is Word-Order Similarity Necessary for Cross-Linguistic Structural Priming?

ERIC Educational Resources Information Center

Chen, Baoguo; Jia, Yuefang; Wang, Zhu; Dunlap, Susan; Shin, Jeong-Ah

2013-01-01

This article presents two experiments employing two structural priming paradigms that investigated whether cross-linguistic syntactic priming occurred in Chinese and English passive sentences that differ in word order (production-to-production priming in Experiment 1 and comprehension-to-production priming in Experiment 2). Results revealed that…

Can Achievement Goals be Primed in Competitive Tasks?

PubMed Central

Greenlees, Iain; Figgins, Sean; Kearney, Philip

2014-01-01

This study examined whether achievement goal priming effects would be observed within an overtly competitive setting. Male soccer players (N = 66) volunteered to participate in a soccer penalty-kick taking competition during which they took 20 penalty-kicks on 2 occasions. Following a pretest, participants were allocated to 1 of 5 priming conditions. Immediately prior to the posttest, participants in the priming conditions were asked to complete what was presented as an ostensibly unrelated task that took the form of either a computer task (subliminal priming) or wordsearch task (supraliminal priming). Results revealed that priming had no significant influence on performance. PMID:25031692

The pros and cons of masked priming.

PubMed

Forster, K I

1998-03-01

Masked priming paradigms offer the promise of tapping automatic, strategy-free lexical processing, as evidenced by the lack of expectancy disconfirmation effects, and proportionality effects in semantic priming experiments. But several recent findings suggest the effects may be prelexical. These findings concern nonword priming effects in lexical decision and naming, the effects of mixed-case presentation on nonword priming, and the dependence of priming on the nature of the distractors in lexical decision, suggesting possible strategy effects. The theory underlying each of these effects is discussed, and alternative explanations are developed that do not preclude a lexical basis for masked priming effects.

Evaluative Priming in the Pronunciation Task.

PubMed

Klauer, Karl Christoph; Becker, Manuel; Spruyt, Adriaan

2016-01-01

We replicated and extended a study by Spruyt and Hermans (2008) in which picture primes engendered an evaluative-priming effect on the pronunciation of target words. As preliminary steps, we assessed data reproducibility of the original study, conducted Pilot Study I to identify highly semantically related prime-target pairs, reanalyzed the original data excluding such pairs, conducted Pilot Study II to demonstrate that we can replicate traditional associative priming effects in the pronunciation task, and conducted Pilot Study III to generate relatively unrelated sets of prime pictures and target words. The main study comprised three between-participants conditions: (1) a close replication of the original study, (2) the same condition excluding highly related prime-target pairs, and (3) a condition based on the relatively unrelated sets of prime pictures and target words developed in Pilot Study III. There was little evidence for an evaluative priming effect independent of semantic relatedness.

Long-lasting effect of subliminal processes on cardiovascular responses and performance.

PubMed

Capa, Rémi L; Cleeremans, Axel; Bustin, Gaëlle M; Hansenne, Michel

2011-07-01

Students were exposed to a priming task in which subliminal representations of the goal of studying were directly paired (priming-positive group) or not (priming group) to positive words. A control group without subliminal prime of the goal was added. Just after the priming task, students performed an easy or a difficult learning task based on their coursework. Participants in the priming-positive group performed better and had a stronger decrease of pulse transit time and pulse wave amplitude reactivity than participants of the two other groups, but only during the difficult condition. Results suggested that subliminal priming induces effortful behavior extending over twenty five minutes but only when the primes had been associated with visible positive words acting as a reward. These findings provide evidence that subliminal priming can have long-lasting effects on behaviors typical of daily life. Copyright © 2011 Elsevier B.V. All rights reserved.

Conceptual and non-conceptual repetition priming in category exemplar generation: Evidence from bilinguals.

PubMed

Francis, Wendy S; Fernandez, Norma P; Bjork, Robert A

2010-10-01

One measure of conceptual implicit memory is repetition priming in the generation of exemplars from a semantic category, but does such priming transfer across languages? That is, do the overlapping conceptual representations for translation equivalents provide a sufficient basis for such priming? In Experiment 1 (N=96) participants carried out a deep encoding task, and priming between languages was statistically reliable, but attenuated, relative to within-language priming. Experiment 2 (N=96) replicated the findings of Experiment 1 and assessed the contributions of conceptual and non-conceptual processes using a levels-of-processing manipulation. Words that underwent shallow encoding exhibited within-language, but not between-language, priming. Priming in shallow conditions cannot therefore be explained by incidental activation of the concept. Instead, part of the within-language priming effect, even under deep-encoding conditions, is due to increased availability of language-specific lemmas or phonological word forms.

Conceptual and Non-conceptual Repetition Priming in Category Exemplar Generation: Evidence from Bilinguals

PubMed Central

Francis, Wendy S.; Fernandez, Norma P.; Bjork, Robert A.

2010-01-01

One measure of conceptual implicit memory is repetition priming in the generation of exemplars from a semantic category, but does such priming transfer across languages? That is, do the overlapping conceptual representations for translation equivalents provide a sufficient basis for such priming? In Experiment 1 (N = 96), participants carried out a deep encoding task, and priming between languages was statistically reliable, but attenuated, relative to within-language priming. Experiment 2 (N = 96) replicated the findings of Experiment 1 and assessed the contributions of conceptual and non-conceptual processes using a levels-of-processing manipulation. Words that underwent shallow encoding exhibited within-language, but not between-language, priming. Priming in shallow conditions cannot, therefore, be explained by incidental activation of the concept. Instead, part of the within-language priming effect, even under deep-encoding conditions, is due to increased availability of language-specific lemmas or phonological word forms. PMID:20924951

Masked priming by misspellings: Word frequency moderates the effects of SOA and prime-target similarity.

PubMed

Burt, Jennifer S

2016-02-01

University students made lexical decisions to eight- or nine-letter words preceded by masked primes that were the target, an unrelated word, or a typical misspelling of the target. At a stimulus onset asynchrony (SOA) of 47 ms, primes that were misspellings of the target produced a priming benefit for low-, medium-, and high-frequency words, even when the misspelled primes were changed to differ phonologically from their targets. At a longer SOA of 80 ms, misspelled primes facilitated lexical decisions only to medium- and low-frequency targets, and a phonological change attenuated the benefit for medium-frequency targets. The results indicate that orthographic similarity can be preserved over changes in letter position and word length, and that the priming effect of misspelled words at the shorter SOA is orthographically based. Orthographic-priming effects depend on the quality of the orthographic learning of the target word.

The precedence of topological change over top-down attention in masked priming.

PubMed

Huang, Yan; Zhou, Tiangang; Chen, Lin

2011-10-14

Recent data indicate that unconscious masked priming can be mediated by top-down attentional set, so that priming effects of congruence between a masked prime and a subsequent probe vanish when the congruence ceases to be task relevant. Here, we show that, while the attentional set determines masked priming for color and orientation features, it does not fully determine priming based on the topological properties of stimuli. Specifically, across a series of different choice-RT tasks, we find that topological congruence between prime and probe stimuli affects RTs for the probes even when other stimulus information (e.g., color or orientation) is required for the response, whereas congruence priming effects of color or orientation occur only when these features are response relevant. Our results suggest that changes in topological properties take precedence over task-directed top-down attentional modulation in masked priming.

The Interdependence of Long- and Short-Term Components in Unmasked Repetition Priming: An Indication of Shared Resources.

PubMed

Merema, Matt R; Speelman, Craig P

2015-01-01

It has been suggested that unmasked repetition priming is composed of distinct long-and short-term priming components. The current study sought to clarify the relationship between these components by examining the relationship between them. A total of 60 people (45 females, 15 males) participated in a computer-based lexical decision task designed to measure levels of short-term priming across different levels of long-term priming. The results revealed an interdependent relationship between the two components, whereby an increase in long-term priming prompted a decrease in short-term priming. Both long-term and short-term priming were accurately captured by a single power function over seven minutes post repetition, suggesting the two components may draw on the same resources. This interdependence between long- and short-term priming may serve to improve fluency in reading.

Investigating a memory-based account of negative priming: support for selection-feature mismatch.

PubMed

MacDonald, P A; Joordens, S

2000-08-01

Using typical and modified negative priming tasks, the selection-feature mismatch account of negative priming was tested. In the modified task, participants performed selections on the basis of a semantic feature (e.g., referent size). This procedure has been shown to enhance negative priming (P. A. MacDonald, S. Joordens, & K. N. Seergobin, 1999). Across 3 experiments, negative priming occurred only when the repeated item mismatched in terms of the feature used as the basis for selections. When the repeated item was congruent on the selection feature across the prime and probe displays, positive priming arose. This pattern of results appeared in both the ignored- and the attended-repetition conditions. Negative priming does not result from previously ignoring an item. These findings strongly support the selection-feature mismatch account of negative priming and refute both the distractor inhibition and the episodic-retrieval explanations.

SOA does not Reveal the Absolute Time Course of Cognitive Processing in Fast Priming Experiments

PubMed Central

Tzur, Boaz; Frost, Ram

2007-01-01

Applying Bloch's law to visual word recognition research, both exposure duration of the prime and its luminance determine the prime's overall energy, and consequently determine the size of the priming effect. Nevertheless, experimenters using fast-priming paradigms traditionally focus only on the SOA between prime and target to reflect the absolute speed of cognitive processes under investigation. Some of the discrepancies in results regarding the time course of orthographic and phonological activation in word recognition research may be due to this factor. This hypothesis was examined by manipulating parametrically the luminance of the prime and its exposure duration, measuring their joint impact on masked repetition priming. The results show that small and non-significant priming effects can be more than tripled as a result of simply increasing luminance, when SOA is kept constant. Moreover, increased luminance may compensate for briefer exposure duration and vice versa. PMID:18379635

Non-cognate translation priming in masked priming lexical decision experiments: A meta-analysis.

PubMed

Wen, Yun; van Heuven, Walter J B

2017-06-01

The masked translation priming paradigm has been widely used in the last 25 years to investigate word processing in bilinguals. Motivated by studies reporting mixed findings, in particular for second language (L2) to first language (L1) translation priming, we conducted, for the first time in the literature, a meta-analysis of 64 masked priming lexical decision experiments across 24 studies to assess the effect sizes of L1-L2 and L2-L1 non-cognate translation priming effects in bilinguals. Our meta-analysis also investigated the influence of potential moderators of translation priming effects. The results provided clear evidence of significant translation priming effects for both directions, with L1-L2 translation priming significantly larger than L2-L1 translation priming (i.e., effect size of 0.86 vs. 0.31). The analyses also revealed that L1-L2 translation effect sizes were moderated by the interval between prime and target (ISI), whereas L2-L1 translation effect sizes were modulated by the number of items per cell. Theoretical and methodological implications of this meta-analysis are discussed and recommendations for future studies are provided.

Priming of familiar and unfamiliar visual objects over delays in young and older adults.

PubMed

Soldan, Anja; Hilton, H John; Cooper, Lynn A; Stern, Yaakov

2009-03-01

Although priming of familiar stimuli is usually age invariant, little is known about how aging affects priming of preexperimentally unfamiliar stimuli. Therefore, this study investigated the effects of aging and encoding-to-test delays (0 min, 20 min, 90 min, and 1 week) on priming of unfamiliar objects in block-based priming paradigms. During the encoding phase, participants viewed pictures of novel objects (Experiments 1 and 2) or novel and familiar objects (Experiment 3) and judged their left-right orientation. In the test block, priming was measured using the possible-impossible object-decision test (Experiment 1), symmetric-asymmetric object-decision test (Experiment 2), and real-nonreal object-decision test (Experiment 3). In Experiments 1 and 2, young adults showed priming for unfamiliar objects at all delays, whereas older adults whose baseline task performance was similar to that of young adults did not show any priming. Experiment 3 found no effects of age or delay on priming of familiar objects; however, priming of unfamiliar objects was only observed in the young participants. This suggests that when older adults cannot rely on preexisting memory representations, age-related deficits in priming can emerge.

Does conal prime CANAL more than cinal? Masked phonological priming effects in Spanish with the lexical decision task.

PubMed

Pollatsek, Alexander; Perea, Manuel; Carreiras, Manuel

2005-04-01

Evidence for an early involvement of phonology in word identification usually relies on the comparison between a target word preceded by a homophonic prime and an orthographic control (rait-RATE vs. raut-RATE). This comparison rests on the assumption that the two control primes are equally orthographically similar to the target. Here, we tested for phonological effects with a masked priming paradigm in which orthographic similarity between priming conditions was perfectly controlled at the letter level and in which identification of the prime was virtually at chance for both stimulus onset asynchronies (SOAs) (66 and 50 msec). In the key prime-target pairs, each prime differed from the target by one vowel letter, but one changed the sound of the initial c, and the other did not (cinal-CANAL vs. conal-CANAL). In the control prime-target pairs, the primes had the identical vowel manipulation, but neither changed the initial consonant sound (pinel-PANEL vs. ponel-PANEL). For both high- and low-frequency words, lexical decision responses to the target were slower when the prime changed the sound of the c than when it did not, whereas there was no difference for the controls at both SOAs. However, this phonological effect was small and was not significant when the SOA was 50 msec. The pattern of data is consistent with an early phonological coding of primes that occurs just a little later than orthographic coding.

Does Research Training During Residency Promote Scholarship and Influence Career Choice? A Cross-Sectional Analysis of a 10-Year Cohort of the UCSF-PRIME Internal Medicine Residency Program.

PubMed

Kohlwes, Jeffrey; O'Brien, Bridget; Stanley, Marion; Grant, Ross; Shunk, Rebecca; Connor, Denise; Cornett, Patricia; Hollander, Harry

2016-01-01

The Association of Program Directors in Internal Medicine, the Accreditation Council for Graduate Medical Education, the Alliance for Academic Internal Medicine, and the Carnegie Foundation report on medical education recommend creating individualized learning pathways during medical training so that learners can experience broader professional roles beyond patient care. Little data exist to support the success of these specialized pathways in graduate medical education. We present the 10-year experience of the Primary Care Medicine Education (PRIME) track, a clinical-outcomes research pathway for internal medicine residents at the University of California San Francisco (UCSF). We hypothesized that participation in an individualized learning track, PRIME, would lead to a greater likelihood of publishing research from residency and accessing adequate career mentorship and would be influential on subsequent alumni careers. We performed a cross-sectional survey of internal medicine residency alumni from UCSF who graduated in 2001 through 2010. We compared responses of PRIME and non-PRIME categorical alumni. We used Pearson's chi-square and Student's t test to compare PRIME and non-PRIME alumni on categorical and continuous variables. Sixty-six percent (211/319) of alumni responded to the survey. A higher percentage of PRIME alumni published residency research projects compared to non-PRIME alumni (64% vs. 40%; p = .002). The number of PRIME alumni identifying research as their primary career role was not significantly different from non-PRIME internal medicine residency graduates (35% of PRIME vs. 29% non-PRIME). Process measures that could explain these findings include adequate access to mentors (M 4.4 for PRIME vs. 3.6 for non-PRIME alumni, p < .001, on a 5-point Likert scale) and agreeing that mentoring relationships affected career choice (M 4.2 for PRIME vs. 3.7 for categorical alumni, p = .001). Finally, 63% of PRIME alumni agreed that their research experience during residency influenced their subsequent career choice versus 46% of non-PRIME alumni (p = .023). Our results support the concept that providing residents with an individualized learning pathway focusing on clinical outcomes research during residency enables them to successfully publish manuscripts and access mentorship, and may influence subsequent career choice. Implementation of individualized residency program tracks that nurture academic interests along with clinical skills can support career development within medicine residency programs.

"Replicable effects of primes on human behavior": Correction to Payne et al. (2016).

PubMed

2016-12-01

Reports an error in "Replicable effects of primes on human behavior" by B. Keith Payne, Jazmin L. Brown-Iannuzzi and Chris Loersch ( Journal of Experimental Psychology: General , 2016[Oct], Vol 145[10], 1269-1279). In the article, the graph in Figure 5 did not contain the asterisk mentioned in the figure caption, which was intended to indicate a statistically significant difference between bet and pass prime. The online version of this article has been corrected. (The following abstract of the original article appeared in record 2016-46925-002.) The effect of primes (i.e., incidental cues) on human behavior has become controversial. Early studies reported counterintuitive findings, suggesting that primes can shape a wide range of human behaviors. Recently, several studies failed to replicate some earlier priming results, raising doubts about the reliability of those effects. We present a within-subjects procedure for priming behavior, in which participants decide whether to bet or pass on each trial of a gambling game. We report 6 replications (N = 988) showing that primes consistently affected gambling decisions when the decision was uncertain. Decisions were influenced by primes presented visibly, with a warning to ignore the primes (Experiments 1 through 3) and with subliminally presented masked primes (Experiment 4). Using a process dissociation procedure, we found evidence that primes influenced responses through both automatic and controlled processes (Experiments 5 and 6). Results provide evidence that primes can reliably affect behavior, under at least some conditions, without intention. The findings suggest that the psychological question of whether behavior priming effects are real should be separated from methodological issues affecting how easily particular experimental designs will replicate. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Functional dissociations in top-down control dependent neural repetition priming.

PubMed

Klaver, Peter; Schnaidt, Malte; Fell, Jürgen; Ruhlmann, Jürgen; Elger, Christian E; Fernández, Guillén

2007-02-15

Little is known about the neural mechanisms underlying top-down control of repetition priming. Here, we use functional brain imaging to investigate these mechanisms. Study and repetition tasks used a natural/man-made forced choice task. In the study phase subjects were required to respond to either pictures or words that were presented superimposed on each other. In the repetition phase only words were presented that were new, previously attended or ignored, or picture names that were derived from previously attended or ignored pictures. Relative to new words we found repetition priming for previously attended words. Previously ignored words showed a reduced priming effect, and there was no significant priming for pictures repeated as picture names. Brain imaging data showed that neural priming of words in the left prefrontal cortex (LIPFC) and left fusiform gyrus (LOTC) was affected by attention, semantic compatibility of superimposed stimuli during study and cross-modal priming. Neural priming reduced for words in the LIPFC and for words and pictures in the LOTC if stimuli were previously ignored. Previously ignored words that were semantically incompatible with a superimposed picture during study induce increased neural priming compared to semantically compatible ignored words (LIPFC) and decreased neural priming of previously attended pictures (LOTC). In summary, top-down control induces dissociable effects on neural priming by attention, cross-modal priming and semantic compatibility in a way that was not evident from behavioral results.

Electrophysiology reveals semantic priming at a short SOA irrespective of depth of prime processing.

PubMed

Küper, Kristina; Heil, Martin

2009-04-03

The otherwise robust behavioral semantic priming effect is reduced to the point of being absent when a letter search has to be performed on the prime word. As a result the automaticity of semantic activation has been called into question. It is unclear, however, in how far automatic processes are even measurable in the letter search priming paradigm as the prime task necessitates a long prime-probe stimulus-onset asynchrony (SOA). In a modified procedure, a short SOA can be realized by delaying the prime task response until after participants have made a lexical decision on the probe. While the absence of lexical decision priming has already been demonstrated in this design it seems premature to draw any definite conclusions from this purely behavioral result since event related potential (ERP) measures have been shown to be a more sensitive index of semantic activation. Using the modified paradigm we thus recorded ERP in addition to lexical decision times. Stimuli were presented at two different SOAs (240 ms vs. 840 ms) and participants performed either a grammatical discrimination (Experiment 1) or a letter search (Experiment 2) on the prime. Irrespective of prime task, the modulation of the N400, the ERP correlate of semantic activation, provided clear-cut evidence of semantic processing at the short SOA. Implications for theories of semantic activation as well as the constraints of the delayed prime task procedure are discussed.

The semantic origin of unconscious priming: Behavioral and event-related potential evidence during category congruency priming from strongly and weakly related masked words.

PubMed

Ortells, Juan J; Kiefer, Markus; Castillo, Alejandro; Megías, Montserrat; Morillas, Alejandro

2016-01-01

The mechanisms underlying masked congruency priming, semantic mechanisms such as semantic activation or non-semantic mechanisms, for example response activation, remain a matter of debate. In order to decide between these alternatives, reaction times (RTs) and event-related potentials (ERPs) were recorded in the present study, while participants performed a semantic categorization task on visible word targets that were preceded either 167 ms (Experiment 1) or 34 ms before (Experiment 2) by briefly presented (33 ms) novel (unpracticed) masked prime words. The primes and targets belonged to different categories (unrelated), or they were either strongly or weakly semantically related category co-exemplars. Behavioral (RT) and electrophysiological masked congruency priming effects were significantly greater for strongly related pairs than for weakly related pairs, indicating a semantic origin of effects. Priming in the latter condition was not statistically reliable. Furthermore, priming effects modulated the N400 event-related potential (ERP) component, an electrophysiological index of semantic processing, but not ERPs in the time range of the N200 component, associated with response conflict and visuo-motor response priming. The present results demonstrate that masked congruency priming from novel prime words also depends on semantic processing of the primes and is not exclusively driven by non-semantic mechanisms such as response activation. Copyright © 2015 Elsevier B.V. All rights reserved.

Priming Ability-Relevant Social Categories Improves Intellectual Test Performance

ERIC Educational Resources Information Center

Lin, Phoebe S.; Kennette, Lynne N.; Van Havermaet, Lisa R.; Frank, Nichole M.; McIntyre, Rusty B.

2012-01-01

Research shows that priming affects behavioral tasks; fewer studies, however, have been conducted on how social category primes affect cognitive tasks. The present study aimed to examine the effects of social category primes on math performance and word recall. It was hypothesized that Asian prime words would improve math performance and word…

Problems with Primes

ERIC Educational Resources Information Center

Melrose, Tim; Scott, Paul

2005-01-01

This article discusses prime numbers, defined as integers greater than 1 that are divisible only by only themselves and the number 1. A positive integer greater than 1 that is not a prime is called composite. The number 1 itself is considered neither prime nor composite. As the name suggests, prime numbers are one of the most basic but important…

Prime Retrieval of Motor Responses in Negative Priming

ERIC Educational Resources Information Center

Mayr, Susanne; Buchner, Axel; Dentale, Sandra

2009-01-01

Three auditory identification experiments were designed to specify the prime-response retrieval model of negative priming (S. Mayr & A. Buchner, 2006), which assumes that the prime response is retrieved in ignored repetition trials and interferes with probe responding. In Experiment 1, shortly before (in Experiment 1A) or after (in Experiment 1B)…

Pure Mediated Priming: A Retrospective Semantic Matching Model

ERIC Educational Resources Information Center

Jones, Lara L.

2010-01-01

Mediated priming refers to the activation of a target (e.g., "stripes") by a prime (e.g., "lion") that is related indirectly via a connecting mediator (e.g., tiger). In previous mediated priming studies (e.g., McNamara & Altarriba, 1988), the mediator was associatively related to the prime. In contrast, pure mediated…

The negative priming effect in cognitive conflict processing.

PubMed

Pan, Fada; Shi, Liang; Lu, Qingyun; Wu, Xiaogang; Xue, Song; Li, Qiwei

2016-08-15

The present study used event-related potentials (ERPs) to investigate the specific physiological mechanisms underlying the negative nature of cognitive conflict and its influence on affective word evaluations. The present study used an affective priming paradigm where Stroop stimuli were presented for 200ms after which affective target words had to be evaluated as being positive or negative. Behavioral results showed that reaction times (RTs) were shorter for positive targets following congruent primes relative to incongruent primes, and for negative targets following incongruent primes relative to congruent primes. The ERP results showed that the N2 amplitude (200-300ms) for incongruent stimuli was significantly larger than for congruent stimuli in the Stroop task, which indicated a significant conflict effect. Moreover, the N400 amplitude (300-500ms) was smaller for negative words following incongruent primes relative to congruent primes, and for positive words following congruent primes relative to incongruent primes. The results demonstrated that cognitive conflict modulated both behavioral and electrophysiological correlates of subsequent emotional processing, consistent with its hypothesized registration as an aversive signal. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Wrath of God: religious primes and punishment

PubMed Central

McKay, Ryan; Efferson, Charles; Whitehouse, Harvey; Fehr, Ernst

2011-01-01

Recent evidence indicates that priming participants with religious concepts promotes prosocial sharing behaviour. In the present study, we investigated whether religious priming also promotes the costly punishment of unfair behaviour. A total of 304 participants played a punishment game. Before the punishment stage began, participants were subliminally primed with religion primes, secular punishment primes or control primes. We found that religious primes strongly increased the costly punishment of unfair behaviours for a subset of our participants—those who had previously donated to a religious organization. We discuss two proximate mechanisms potentially underpinning this effect. The first is a ‘supernatural watcher’ mechanism, whereby religious participants punish unfair behaviours when primed because they sense that not doing so will enrage or disappoint an observing supernatural agent. The second is a ‘behavioural priming’ mechanism, whereby religious primes activate cultural norms pertaining to fairness and its enforcement and occasion behaviour consistent with those norms. We conclude that our results are consistent with dual inheritance proposals about religion and cooperation, whereby religions harness the byproducts of genetically inherited cognitive mechanisms in ways that enhance the survival prospects of their adherents. PMID:21106588

Face (and Nose) Priming for Book: The Malleability of Semantic Memory

PubMed Central

Coane, Jennifer H.; Balota, David A.

2010-01-01

There are two general classes of models of semantic structure that support semantic priming effects. Feature-overlap models of semantic priming assume that shared features between primes and targets are critical (e.g., cat-DOG). Associative accounts assume that contextual co-occurrence is critical and that the system is organized along associations independent of featural overlap (e.g., leash-DOG). If unrelated concepts can become related as a result of contextual co-occurrence, this would be more supportive of associative accounts and provide insight into the nature of the network underlying “semantic” priming effects. Naturally co-occurring recent associations (e.g., face-BOOK) were tested under conditions that minimize strategic influences (i.e., short stimulus onset asynchrony, low relatedness proportion) in a semantic priming paradigm. Priming for new associations did not differ from the priming found for pre-existing relations (e.g., library-BOOK). Mediated priming (e.g., nose-BOOK) was also found. These results suggest that contextual associations can result in the reorganization of the network that subserves “semantic” priming effects. PMID:20494866

Inhibitory phonetic priming: Where does the effect come from?

PubMed

Dufour, Sophie; Frauenfelder, Ulrich Hans

2016-01-01

Both phonological and phonetic priming studies reveal inhibitory effects that have been interpreted as resulting from lexical competition between the prime and the target. We present a series of phonetic priming experiments that contrasted this lexical locus explanation with that of a prelexical locus by manipulating the lexical status of the prime and the target and the task used. In the related condition of all experiments, spoken targets were preceded by spoken primes that were phonetically similar but shared no phonemes with the target (/bak/-/dεt/). In Experiments 1 and 2, word and nonword primes produced an inhibitory effect of equal size in shadowing and same-different tasks respectively. Experiments 3 and 4 showed robust inhibitory phonetic priming on both word and nonword targets in the shadowing task, but no effect at all in a lexical decision task. Together, these findings show that the inhibitory phonetic priming effect occurs independently of the lexical status of both the prime and the target, and only in tasks that do not necessarily require the activation of lexical representations. Our study thus argues in favour of a prelexical locus for this effect.

Phasic affective modulation of semantic priming.

PubMed

Topolinski, Sascha; Deutsch, Roland

2013-03-01

The present research demonstrates that very brief variations in affect, being around 1 s in length and changing from trial to trial independently from semantic relatedness of primes and targets, modulate the amount of semantic priming. Implementing consonant and dissonant chords (Experiments 1 and 5), naturalistic sounds (Experiment 2), and visual facial primes (Experiment 3) in an (in)direct semantic priming paradigm, as well as brief facial feedback in a summative priming paradigm (Experiment 4), yielded increased priming effects under brief positive compared to negative affect. Furthermore, this modulation took place on the level of semantic spreading rather than on strategic mechanisms (Experiment 5). Alternative explanations such as distraction, motivation, arousal, and cognitive tuning could be ruled out. This phasic affective modulation constitutes a mechanism overlooked thus far that may contaminate priming effects in all priming paradigms that involve affective stimuli. Furthermore, this mechanism provides a novel explanation for the observation that priming effects are usually larger for positive than for negative stimuli. Finally, it has important implications for linguistic research, by suggesting that association norms may be biased for affective words. (c) 2013 APA, all rights reserved.

Exploring the additive effects of stimulus quality and word frequency: the influence of local and list-wide prime relatedness.

PubMed

Scaltritti, Michele; Balota, David A; Peressotti, Francesca

2013-01-01

Stimulus quality and word frequency produce additive effects in lexical decision performance, whereas the semantic priming effect interacts with both stimulus quality and word frequency effects. This pattern places important constraints on models of visual word recognition. In Experiment 1, all three variables were investigated within a single speeded pronunciation study. The results indicated that the joint effects of stimulus quality and word frequency were dependent upon prime relatedness. In particular, an additive effect of stimulus quality and word frequency was found after related primes, and an interactive effect was found after unrelated primes. It was hypothesized that this pattern reflects an adaptive reliance on related prime information within the experimental context. In Experiment 2, related primes were eliminated from the list, and the interactive effects of stimulus quality and word frequency found following unrelated primes in Experiment 1 reverted to additive effects for the same unrelated prime conditions. The results are supportive of a flexible lexical processor that adapts to both local prime information and global list-wide context.

Priming effects on labile and stable soil organic carbon decomposition: Pulse dynamics over two years

PubMed Central

Han, Xiaozeng; Yu, Wantai; Wang, Peng; Cheng, Weixin

2017-01-01

Soil organic carbon (SOC) is a major component in the global carbon cycle. Yet how input of plant litter may influence the loss of SOC through a phenomenon called priming effect remains highly uncertain. Most published results about the priming effect came from short-term investigations for a few weeks or at the most for a few months in duration. The priming effect has not been studied at the annual time scale. In this study for 815 days, we investigated the priming effect of added maize leaves on SOC decomposition of two soil types and two treatments (bare fallow for 23 years, and adjacent old-field, represent stable and relatively labile SOC, respectively) of SOC stabilities within each soil type, using a natural 13C-isotope method. Results showed that the variation of the priming effect through time had three distinctive phases for all soils: (1) a strong negative priming phase during the first period (≈0–90 days); (2) a pulse of positive priming phase in the middle (≈70–160 and 140–350 days for soils from Hailun and Shenyang stations, respectively); and (3) a relatively stabilized phase of priming during the last stage of the incubation (>160 days and >350 days for soils from Hailun and Shenyang stations, respectively). Because of major differences in soil properties, the two soil types produced different cumulative priming effects at the end of the experiment, a positive priming effect of 3–7% for the Mollisol and a negative priming effect of 4–8% for the Alfisol. Although soil types and measurement times modulated most of the variability of the priming effect, relative SOC stabilities also influenced the priming effect for a particular soil type and at a particular dynamic phase. The stable SOC from the bare fallow treatment tended to produce a narrower variability during the first phase of negative priming and also during the second phase of positive priming. Averaged over the entire experiment, the stable SOC (i.e., the bare fallow) was at least as responsive to priming as the relatively labile SOC (i.e., the old-field) if not more responsive. The annual time scale of our experiment allowed us to demonstrate the three distinctive phases of the priming effect. Our results highlight the importance of studying the priming effect by investigating the temporal dynamics over longer time scales. PMID:28934287

Subliminal semantic priming in near absence of attention: A cursor motion study.

PubMed

Xiao, Kunchen; Yamauchi, Takashi

2015-12-15

The role of attention in subliminal semantic priming remains controversial: some researchers argue that attention is necessary for subliminal semantic priming, while others suggest that subliminal semantic processing is free from the influence of attention. The present study employs a cursor motion method to measure priming and evaluate the influence of attention. Specifically, by employing a semantic priming task developed by Naccache, Blandin, and Dehaene (2002), we investigate the extent to which top-down attention influences semantic priming. Results indicate that, consistent with the Naccache et al. (2002) results, attention facilitates priming. However, inconsistent with their theory, significant priming is still observed even in near absence of attention. We suggest that top-down attention helps but is not necessary for subliminal semantic processing. Copyright © 2015 Elsevier Inc. All rights reserved.

The 'prime-ome': towards a holistic approach to priming.

PubMed

Balmer, Andrea; Pastor, Victoria; Gamir, Jordi; Flors, Victor; Mauch-Mani, Brigitte

2015-07-01

Plants can be primed to respond faster and more strongly to stress and multiple pathways, specific for the encountered challenge, are involved in priming. This adaptability of priming makes it difficult to pinpoint an exact mechanism: the same phenotypic observation might be the consequence of unrelated underlying events. Recently, details of the molecular aspects of establishing a primed state and its transfer to offspring have come to light. Advances in techniques for detection and quantification of elements spanning the fields of transcriptomics, proteomics, and metabolomics, together with adequate bioinformatics tools, will soon allow us to take a holistic approach to plant defence. This review highlights the state of the art of new strategies to study defence priming in plants and provides perspectives towards 'prime-omics'. Copyright © 2015 Elsevier Ltd. All rights reserved.

Crystal structure and magnetic properties of '{alpha} Prime Prime -Fe{sub 16}N{sub 2}' containing residual {alpha}-Fe prepared by low-temperature ammonia nitridation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamashita, S.; Masubuchi, Y.; Nakazawa, Y.

2012-10-15

Slight enhancement of saturation magnetization to 219 A m{sup 2} kg{sup -1} was observed from 199 A m{sup 2} kg{sup -1} for the original {alpha}-Fe on the intermediate nitrided mixture of '{alpha} Prime Prime -Fe{sub 16}N{sub 2}' with residual {alpha}-Fe among the low temperature ammonia nitridation products under 5 T magnetic field at room temperature. The value changed not linearly against the yield as had been expected. Crystal structure refinement indicated that the phase similar to {alpha} Prime Prime -Fe{sub 16}N{sub 2} had deviations on its lattice constants and positional parameters, compared to previously reported values for {alpha} Prime Primemore » -Fe{sub 16}N{sub 2}. Spin-polarized total energy calculations were performed using the projector-augmented wave method as implemented in the Vienna ab-initio simulation package (VASP) to calculate magnetic moment on the refined crystal structure of the intermediate '{alpha} Prime Prime -Fe{sub 16}N{sub 2}'. The calculations supported the observed magnetization enhancement in the intermediate nitridation product. - Graphical abstract: Crystal structural parameters slightly change in the intermediate nitrided '{alpha} Prime Prime -Fe{sub 16}N{sub 2}' from those in {alpha} Prime Prime -Fe{sub 16}N{sub 2} to show the magnetization maxima in the mixture of '{alpha} Prime Prime -Fe{sub 16}N{sub 2}' and the residual {alpha}-F. Highlights: Black-Right-Pointing-Pointer Larger magnetization was observed than the value of Fe{sub 16}N{sub 2} on its intermediate nitrided mixture with residual {alpha}-Fe. Black-Right-Pointing-Pointer The enhancement was related to the crystal structural deviation from Fe{sub 16}N{sub 2} on the intermediate nitride. Black-Right-Pointing-Pointer It was supported by spin-polarized total energy calculation using the deviated structure.« less

The Effect of Storage Condition and Duration on the Deterioration of Primed Rice Seeds

PubMed Central

Wang, Weiqin; He, Aibin; Peng, Shaobing; Huang, Jianliang; Cui, Kehui; Nie, Lixiao

2018-01-01

Seed priming is a successful practice to improve crop establishment under adverse environment. However, reduced longevity of primed rice (Oryza sativa L.) seeds during storage limited the adoption of this technique. Present study investigated the effect of temperature, relative air humidity (RH) and oxygen on the longevity of primed rice seeds in a range of 60 days storage. In addition, the biochemical and morphological mechanisms associated with deterioration of primed seeds during storage were explored. Three types of priming treated rice seeds and one non-primed control were stored under (1) low temperature-vacuum (LT-V), (2) room temperature-vacuum (RT-V), (3) room temperature-aerobic-low RH (RT-A-LH) and (4) room temperature-aerobic- high RH (RT-A-HH) for 0, 15, 30, 45, and 60 days. The results showed that storage of seeds under different conditions for 15–60 days did not influence the longevity of non-primed rice seeds. Meanwhile, the viability of primed rice seeds did not reduce when stored under LT-V, RT-V, and RT-A-LH, but was significantly reduced under RT-A-HH. Under vacuum condition, the increases of storage temperature (30°C) did not reduce the longevity of primed seeds. Likewise, the oxygen did not influence the longevity of primed rice seeds stored under low RH. Nevertheless, increase of RH significantly reduced the viability of primed seeds stored for 15–60 days. Reduced starch metabolism, the consumption of starch reserves in rice endosperms, the accumulation of malondialdehyde and the decreases of antioxidant enzyme activities might be associated with the deterioration of primed rice seeds during storage. In conclusion, storage of primed seeds under high RH condition beyond 15 days is deteriorative for germination and growth of rice. The primed rice seeds are recommended to store at vacuum or low RH or low temperature condition to ensure good crop establishment. PMID:29487612

The Effect of Storage Condition and Duration on the Deterioration of Primed Rice Seeds.

PubMed

Wang, Weiqin; He, Aibin; Peng, Shaobing; Huang, Jianliang; Cui, Kehui; Nie, Lixiao

2018-01-01

Seed priming is a successful practice to improve crop establishment under adverse environment. However, reduced longevity of primed rice ( Oryza sativa L.) seeds during storage limited the adoption of this technique. Present study investigated the effect of temperature, relative air humidity (RH) and oxygen on the longevity of primed rice seeds in a range of 60 days storage. In addition, the biochemical and morphological mechanisms associated with deterioration of primed seeds during storage were explored. Three types of priming treated rice seeds and one non-primed control were stored under (1) low temperature-vacuum (LT-V), (2) room temperature-vacuum (RT-V), (3) room temperature-aerobic-low RH (RT-A-LH) and (4) room temperature-aerobic- high RH (RT-A-HH) for 0, 15, 30, 45, and 60 days. The results showed that storage of seeds under different conditions for 15-60 days did not influence the longevity of non-primed rice seeds. Meanwhile, the viability of primed rice seeds did not reduce when stored under LT-V, RT-V, and RT-A-LH, but was significantly reduced under RT-A-HH. Under vacuum condition, the increases of storage temperature (30°C) did not reduce the longevity of primed seeds. Likewise, the oxygen did not influence the longevity of primed rice seeds stored under low RH. Nevertheless, increase of RH significantly reduced the viability of primed seeds stored for 15-60 days. Reduced starch metabolism, the consumption of starch reserves in rice endosperms, the accumulation of malondialdehyde and the decreases of antioxidant enzyme activities might be associated with the deterioration of primed rice seeds during storage. In conclusion, storage of primed seeds under high RH condition beyond 15 days is deteriorative for germination and growth of rice. The primed rice seeds are recommended to store at vacuum or low RH or low temperature condition to ensure good crop establishment.

Transition probabilities in OH A 2 sigma + - X 2 pi i: Bands with v prime = 0 and 1, v double prime = 0 to 4

NASA Technical Reports Server (NTRS)

Copeland, Richard A.; Jeffries, Jay B.; Crosley, David R.

1986-01-01

Experimental results for relative vibrational band transition probabilities for v prime = 0 and 1, and v double prime = 0 to 4 in the A-X electronic system of OH are presented. The measurements, part of a larger set involving v prime = 0 to 4 and v double prime = 0 to 6, were made using spectrally dispersed laser-induced fluorescence (LIF) in the burnt gases of a flame. These Einstein coefficients will be useful in dynamics experiments for quantitative LIF determinations of OH radical concentrations in high v double prime.

Allograph priming is based on abstract letter identities: Evidence from Japanese kana.

PubMed

Kinoshita, Sachiko; Schubert, Teresa; Verdonschot, Rinus G

2018-04-23

It is well-established that allographs like the uppercase and lowercase forms of the Roman alphabet (e.g., a and A) map onto the same "abstract letter identity," orthographic representations that are independent of the visual form. Consistent with this, in the allograph match task ("Are 'a' and 'A' the same letter?"), priming by a masked letter prime is equally robust for visually dissimilar prime-target pairs (e.g., d and D) and similar pairs (e.g., c and C). However, in principle this pattern of priming is also consistent with the possibility that allograph priming is purely phonological, based on the letter name. Because different allographic forms of the same letter, by definition, share a letter name, it is impossible to rule out this possibility a priori. In the present study, we investigated the influence of shared letter names by taking advantage of the fact that Japanese is written in two distinct writing systems, syllabic kana-that has two parallel forms, hiragana and katakana-and logographic kanji. Using the allograph match task, we tested whether a kanji prime with the same pronunciation as the target kana (e.g., - い, both pronounced /i/) produces the same amount of priming as a kana prime in the opposite kana form (e.g., イ- い). We found that the kana primes produced substantially greater priming than the phonologically identical kanji prime, which we take as evidence that allograph priming is based on abstract kana identity, not purely phonology. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

5[prime] to 3[prime] nucleic acid synthesis using 3[prime]-photoremovable protecting group

DOEpatents

Pirrung, M.C.; Shuey, S.W.; Bradley, J.C.

1999-06-01

The present invention relates, in general, to a method of synthesizing a nucleic acid, and, in particular, to a method of effecting 5[prime] to 3[prime] nucleic acid synthesis. The method can be used to prepare arrays of oligomers bound to a support via their 5[prime] end. The invention also relates to a method of effecting mutation analysis using such arrays. The invention further relates to compounds and compositions suitable for use in such methods.

The structure of semantic person memory: evidence from semantic priming in person recognition.

PubMed

Wiese, Holger

2011-11-01

This paper reviews research on the structure of semantic person memory as examined with semantic priming. In this experimental paradigm, a familiarity decision on a target face or written name is usually faster when it is preceded by a related as compared to an unrelated prime. This effect has been shown to be relatively short lived and susceptible to interfering items. Moreover, semantic priming can cross stimulus domains, such that a written name can prime a target face and vice versa. However, it remains controversial whether representations of people are stored in associative networks based on co-occurrence, or in more abstract semantic categories. In line with prominent cognitive models of face recognition, which explain semantic priming by shared semantic information between prime and target, recent research demonstrated that priming could be obtained from purely categorically related, non-associated prime/target pairs. Although strategic processes, such as expectancy and retrospective matching likely contribute, there is also evidence for a non-strategic contribution to priming, presumably related to spreading activation. Finally, a semantic priming effect has been demonstrated in the N400 event-related potential (ERP) component, which may reflect facilitated access to semantic information. It is concluded that categorical relatedness is one organizing principle of semantic person memory. ©2011 The British Psychological Society.

Iconic gestures prime words: comparison of priming effects when gestures are presented alone and when they are accompanying speech

PubMed Central

So, Wing-Chee; Yi-Feng, Alvan Low; Yap, De-Fu; Kheng, Eugene; Yap, Ju-Min Melvin

2013-01-01

Previous studies have shown that iconic gestures presented in an isolated manner prime visually presented semantically related words. Since gestures and speech are almost always produced together, this study examined whether iconic gestures accompanying speech would prime words and compared the priming effect of iconic gestures with speech to that of iconic gestures presented alone. Adult participants (N = 180) were randomly assigned to one of three conditions in a lexical decision task: Gestures-Only (the primes were iconic gestures presented alone); Speech-Only (the primes were auditory tokens conveying the same meaning as the iconic gestures); Gestures-Accompanying-Speech (the primes were the simultaneous coupling of iconic gestures and their corresponding auditory tokens). Our findings revealed significant priming effects in all three conditions. However, the priming effect in the Gestures-Accompanying-Speech condition was comparable to that in the Speech-Only condition and was significantly weaker than that in the Gestures-Only condition, suggesting that the facilitatory effect of iconic gestures accompanying speech may be constrained by the level of language processing required in the lexical decision task where linguistic processing of words forms is more dominant than semantic processing. Hence, the priming effect afforded by the co-speech iconic gestures was weakened. PMID:24155738

The Situated Inference Model: An Integrative Account of the Effects of Primes on Perception, Behavior, and Motivation.

PubMed

Loersch, Chris; Payne, B Keith

2011-05-01

The downstream consequences of a priming induction range from changes in the perception of objects in the environment to the initiation of prime-related behavior and goal striving. Although each of these outcomes has been accounted for by separate mechanisms, we argue that a single process could produce all three priming effects. In this article, we introduce the situated inference model of priming, discuss its potential to account for these divergent outcomes with one mechanism, and demonstrate its ability to organize the priming literatures surrounding these effects. According to the model, primes often do not cause direct effects, instead altering only the accessibility of prime-related mental content. This information produces downstream effects on judgment, behavior, or motivation when it is mistakenly viewed as originating from one's own internal thought processes. When this misattribution occurs, the prime-related mental content becomes a possible source of information for solving whatever problems are afforded by the current situation. Because different situations afford very different questions and concerns, the inferred meaning of this prime-related content can vary greatly. The use of this information to answer qualitatively different questions can lead a single prime to produce varied effects on judgment, behavior, and motivation. © The Author(s) 2011.

Incidental Learning of S-R Contingencies in the Masked Prime Task

ERIC Educational Resources Information Center

Schlaghecken, Friederike; Blagrove, Elisabeth; Maylor, Elizabeth A.

2007-01-01

Subliminal motor priming effects in the masked prime paradigm can only be obtained when primes are part of the task set. In 2 experiments, the authors investigated whether the relevant task set feature needs to be explicitly instructed or could be extracted automatically in an incidental learning paradigm. Primes and targets were symmetrical…

The Relative Position Priming Effect Depends on Whether Letters Are Vowels or Consonants

ERIC Educational Resources Information Center

Dunabeitia, Jon Andoni; Carreiras, Manuel

2011-01-01

The relative position priming effect is a type of subset priming in which target word recognition is facilitated as a consequence of priming the word with some of its letters, maintaining their relative position (e.g., "csn" as a prime for "casino"). Five experiments were conducted to test whether vowel-only and consonant-only…