9,861 research outputs found
Ring counter circuit switches multiphase motor direction of rotation
Solid state three-phase counter circuit reverses the direction of rotation of a multiphase motor without changing the phase wiring of the supply current source
Production of Dispersion Alloys with the Aid of Ultrasonics Final Report
Dispersion of inerts in molten matrix by ultrasonic energy, and ultrasonic treatment of alloys to produce dispersion strengthenin
Materials for advanced turbine engines. Volume 1: Advanced blade tip seal system
Project 3, the subject of this technical report, was structured toward the successful engine demonstration of an improved-efficiency, long-life, tip-seal system for turbine blades. The advanced tip-seal system was designed to maintain close operating clearances between turbine blade tips and turbine shrouds and, at the same time, be resistant to environmental effects including high-temperature oxidation, hot corrosion, and thermal cycling. The turbine blade tip comprised an environmentally resistant, activated-diffussion-bonded, monocrystal superalloy combined with a thin layer of aluminium oxide abrasive particles entrapped in an electroplated NiCr matrix. The project established the tip design and joint location, characterized the single-crystal tip alloy and abrasive tip treatment, and established the manufacturing and quality-control plans required to fully process the blades. A total of 171 blades were fully manufactured, and 100 were endurance and performance engine-tested
Institute of Northern Engineering 2006 Annual Report
MESSAGE FROM THE DIRECTOR -- OVERVIEW AND MISSION -- CENTER PROFILES -- ORGANIZATION & CENTER LEADERS -- ARCTIC ENERGY TECHNOLOGY DEVELOPMENT LABORATORY -- ALASKA UNIVERSITY TRANSPORTATION CENTER -- MINERAL INDUSTRY RESEARCH LABORATORY -- PETROLEUM DEVELOPMENT LABORATORY -- WATER & ENVIRONMENTAL RESEARCH CENTER -- INE GENERAL RESEARCH -- ACCOMPLISHMENTS 2006 -- GOALS 2007 -- RESOURCES, FUNDING, AND EXPENDITURE
IL-12 and IL-4 activate a CD39-dependent intrinsic peripheral tolerance mechanism in CD8+ T cells
Immune responses to protein antigens involve CD4+ and CD8+ T cells, which follow distinct programs of differentiation. Naïve CD8 T cells rapidly develop cytotoxic T-cell (CTL) activity after T-cell receptor stimulation, and we have previously shown that this is accompanied by suppressive activity in the presence of specific cytokines, i.e. IL-12 and IL-4. Cytokine-induced CD8+ regulatory T (Treg) cells are one of several Treg-cell phenotypes and are Foxp3− IL-10+ with contact-dependent suppressive capacity. Here, we show they also express high level CD39, an ecto-nucleotidase that degrades extracellular ATP, and this contributes to their suppressive activity. CD39 expression was found to be upregulated on CD8+ T cells during peripheral tolerance induction in vivo, accompanied by release of IL-12 and IL-10. CD39 was also upregulated during respiratory tolerance induction to inhaled allergen and on tumor-infiltrating CD8+ T cells. Production of IL-10 and expression of CD39 by CD8+ T cells was independently regulated, being respectively blocked by extracellular ATP and enhanced by an A2A adenosine receptor agonist. Our results suggest that any CTL can develop suppressive activity when exposed to specific cytokines in the absence of alarmins. Thus negative feedback controls CTL expansion under regulation from both nucleotide and cytokine environment within tissues
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