1,143 research outputs found
Study of vortex valve for medium temperature solid propellants
Fluid state vortex valve secondary injection control system shows considerable promise for future application to solid propellant rocket engine thrust vector control. The single axis injection system tested would be capable of providing secondary injection thrust vector control using 2000 deg F gas
Research study of the vortex valve for medium-temperature solid propellants
Fluid state control system with vortex valves for solid propellant gas generator flow throttlin
Pluies et paramĂštres de conception pour le contrĂŽle qualitatif du ruissellement urbain
Colloque avec actes et comité de lecture. Internationale.International audienc
Stimulation of tPA-dependent provisional extracellular fibrin matrix degradation by human recombinant soluble melanotransferrin
AbstractTissue-type plasminogen activator (tPA) and its substrate plasminogen (Plg) are key components in the fibrinolytic system. We have recently demonstrated, that truncated human recombinant soluble melanotransferrin (sMTf) could stimulate the activation of Plg by urokinase plasminogen activator and inhibit angiogenesis. Since various angiogenesis inhibitors were shown to stimulate tPA-mediated plasminogen activation, we examined the effects of sMTf on tPA-dependent fibrinolysis. This study demonstrated that sMTf enhanced tPA-activation of Plg by 6-fold. sMTf also increased the release of [125I]-fibrin fragments by tPA-activated plasmin. Moreover, we observed that the interaction of sMTf with Plg provoked a change in the fibrin clot structure by cleaving the fibrin α and ÎČ chains. Overall, the present study shows that sMTf modulates tPA-dependent fibrinolysis by modifying the clot structure. These results also suggest that sMTf properties could involve enhanced dissolution of the provisional extracellular fibrin matrix
Solidification mechanisms of chitosanâglycerol phosphate/blood implant for articular cartilage repair
SummaryObjectiveChitosanâglycerol phosphate (chitosan-GP) is a unique polymer solution that is mixed with whole blood and solidified over microfractured or drilled articular cartilage defects in order to elicit a more hyaline repair cartilage. For clinical ease-of-use, a faster in situ solidification is preferred. Therefore, we investigated the mechanisms underlying chitosanâGP/blood implant solidification.MethodsIn vitro solidification of chitosanâGP/blood mixtures, with or without added clotting factors, was evaluated by thromboelastography. Serum was analyzed for the onset of thrombin, platelet, and FXIII activation. In vivo solidification of chitosanâGP/blood mixtures, with and without clotting factors, was evaluated in microdrilled cartilage defects of adult rabbits (N=41 defects).ResultsChitosanâGP/blood clots solidified in an atypical biphasic manner, with higher initial viscosity and minor platelet activation followed by the development of clot tensile strength concomitant with thrombin generation, burst platelet and FXIII activation. Whole blood and chitosanâGP/blood clots developed a similar final clot tensile strength, while polymerâblood clots showed a unique, sustained platelet factor release and greater resistance to lysis by tissue plasminogen activator. Thrombin, tissue factor (TF), and recombinant human activated factor VII (rhFVIIa) accelerated chitosanâGP/blood solidification in vitro (P<0.05). Pre-application of thrombin or rhFVIIa+TF to the surface of drilled cartilage defects accelerated implant solidification in vivo (P<0.05).ConclusionsChitosanâGP/blood implants solidify through coagulation mechanisms involving thrombin generation, platelet activation and fibrin polymerization, leading to a dual fibrinâpolysaccharide clot scaffold that resists lysis and is physically more stable than normal blood clots. Clotting factors have the potential to enhance the practical use, the residency, and therapeutic activity of polymerâblood implants
Radiographic characterization and energy spectrum of the IoGold 125I source Model 3631âA
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135057/1/mp8543.pd
International workshop on immune tolerance induction: consensus recommendations 1
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73382/1/j.1365-2516.2007.01497.x.pd
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