1,533 research outputs found

    IgE-mediated histamine release from nasal mucosa is inhibited by SLPI (secretory leukocyte protease inhibitor) to the level of spontaneous release.

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    The secretory leukocyte protease inhibitor (SLPI) is a low-molecular-weight inhibitor of proteases, such as elastase and cathepsin G which are released from leukocytes during phagocytosis. The purpose of this study was to determine whether or not SLPI is able to inhibit IgE-mediated histamine release. Nasal mucosa from 11 test subjects without atopic disposition was used for this in vitro study. We found that SLPI inhibited histamine release in a dose-dependent way but was without influence on the spontaneous release

    Estimation and Application of 2-D Scattering Matrices for Sparse Array Imaging of Impact Damage in Composite Panels

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    Reliable detection of hidden damage in composites is important for failure prevention in the aerospace industry since these materials are being more frequently used in high stress applications. Structural health monitoring (SHM) via guided wave sensors mounted on or embedded within a composite structure can help detect and localize damage in real-time while also reducing overall maintenance costs. One approach to guided wave SHM is sparse array imaging via the minimum variance algorithm, and it has been shown in prior work that incorporating estimated scattering from expected defects can improve the quality of damage localization and characterization [1]. For this study, impacts were applied to induce delaminations within a composite panel. Wavefield data were recorded on a circle centered at the damage location from multiple incident directions before and after the impacts. Baseline subtraction [2] is used to estimate scattering patterns for each incident direction, and these patterns are combined and interpolated to form a full 2-D scattering matrix. This matrix is then incorporated into the minimum variance imaging algorithm, and imaging efficacy is evaluated for both these impacts and impact damage in other similar composite plates. Results are compared to images generated using simpler scattering assumptions

    Coulomb interaction effects on nonlinear optical response in C60, C70, and higher fullerenes

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    Nonlinear optical properties in the fullerene C60_{60} and the extracted higher fullerenes -- C70_{70}, C76_{76}, C78_{78}, and C84_{84} -- are theoretically investigated by using the exciton formalism and the sum-over-states method. We find that off-resonant third order susceptibilities of higher fullerenes are a few times larger than those of C60_{60}. The magnitude of nonlinearity increases as the optical gap decreases in higher fullerenes. The nonlinearity is nearly proportional to the fourth power of the carbon number when the onsite Coulomb repulsion is 2t2t or 4t4t, tt being the nearest neighbor hopping integral. This result, indicating important roles of Coulomb interactions, agrees with quantum chemical calculations of higher fullerenes.Comment: 8 pages; 3 figures; Figures should be requested to the author (E-mail: [email protected]

    Time course of striatal DeltaFosB-like immunoreactivity and prodynorphin mRNA levels after discontinuation of chronic dopaminomimetic treatment.

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    DFosB-like proteins are particularly stable transcription factors that accumulate in the brain in response to chronic perturbations. In this study we have compared the time-course of striatal FosB/DFosB-like immunoreactivity and prodynorphin mRNA expression after discontinuation of chronic cocaine treatment to intact rats and chronic L-DOPA treatment to unilaterally 6-hydroxydopamine (6-OHDA) lesioned rats. The animals were killed between 3 h and 16 days after the last drug injection. In both treatment paradigms, the druginduced FosB/DFosB immunoreactivity remained significantly elevated in the caudate putamen even at the longest withdrawal period examined. The concomitant upregulation of prodynorphin mRNA, a target of DFosB, paralleled the time-course of DFosB-like immunoreactivity in the 6-OHDA-lesion/L-DOPA model, but was more transient in animals treated with cocaine. These results suggest that DFosB-like proteins have exceptional in vivo stability. In the dopamine-denervated striatum, these proteins may exert sustained effects on the expression of their target genes long after discontinuation of L-DOPA pharmacotherapy

    Effect of nitrogen in backing gas on duplex root weld properties of heavy-walled pipe

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    Duplex stainless steels are increasingly used for offshore subsea components as the technology allows for deeper recovery of oil and gas reserves. Alloy UNS S31803 (EN 1.4462/UNS S32205) combines high strength with good resistance to pitting and crevice corrosion. This grade is alloyed with nitrogen and has good weldability. For heavy-walled process piping intended for subsea sour service, the properties of the root pass are of high importance. For this reason, the effect of using nitrogen in the backing gas was investigated. Test pieces were manually welded with the gas tungsten arc welding (GTAW) process using an ER2209 filler wire. Tensile, bending and hardness testing was carried out and showed acceptable results across all specimens. Higher contents of nitrogen in the backing gas showed more austenite formation and a significant increase in pitting corrosion resistance when compared with pure argon. With Ar + 2 % N2, there was no pitting, but a small weight loss of 1.7 g/m2 was measured. 10 % N2 was required to pass both the corrosion tests ASTM G48 Method A (4 g/m2) and ASTM A923 (1 g/m2). The highest average impact toughness was achieved with pure nitrogen as the backing gas

    Use of remote sensing techniques for inventorying and planning utilization of land resources in South Dakota

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    The basic procedures for interpreting remote sensing imagery to rapidly develop general soils and land use inventories were developed and utilized in Pennington County, South Dakota. These procedures and remote sensing data products were illustrated and explained to many user groups, some of whom are interested in obtaining similar data. The general soils data were integrated with land soils data supplied by the county director of equalization to prepare a land value map. A computer print-out of this map indicating a land value for each quarter section is being used in tax reappraisal of Pennington County. The land use data provided the land use planners with the present use of land in Pennington County. Additional uses of remote sensing applications are also discussed including tornado damage assessment, hail damage evaluation, and presentation of soil and land value information on base maps assembled from ERTS-1 imagery

    Automated three-axis gonioreflectometer for computer graphics applications

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    We describe an automated three-axis BRDF measurement instrument that can help increase the physical realism of computer graphics images by providing light scattering data for the surfaces within a synthetic scene that is to be rendered. To our knowledge, the instrument is unique in combining wide angular coverage (beyond 85 ° from the surface normal), dense sampling of the visible wavelength spectrum (1024 samples), and rapid operation (less than ten hours for complete measurement of an isotropic sample). The gonioreflectometer employs a broadband light source and a detector with a diffraction grating and linear diode array. Validation was achieved by comparisons against reference surfaces and other instruments. The accuracy and spectral and angular ranges of the BRDFs are appropriate for computer graphics imagery, while reciprocity and energy conservation are preserved. Measured BRDFs on rough aluminum, metallic silver automotive paint, and a glossy yellow paint are reported, and an example rendered automotive image is included
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