Effect of the O2 dissociation degree on the rate of anodic evaporation of Al in a low-pressure arc

The results of probe diagnostics and optical emission spectroscopy of Ar-O2 plasma of a low-pressure arc generated under anodic evaporation of Al and an increased (0.32 – 0.48) degree of O2 dissociation are presented. It is shown that an increase in the degree of O2 dissociation at a constant gas flow into the discharge gap leads to a significant (more than 1.5 times) decrease in the density of the evaporated atoms flux and a corresponding decrease in the coating deposition rate. The observed effect is due to the accelerated growth of the oxide film on the melt surface, which leads to the limitation of the flow of evaporated Al atoms by the rate of diffusion through the alumina.

Reconstruction and catalytic activity of hybrid Pd(100)/(111) monolayer over γ-Al2O3(100) in CH4, H2O, and O2 dissociation

The importance for catalysis of the “heterogeneity” of a Pd monolayer induced by interaction with a semi-ionic support was evaluated. The geometry of Pd monolayer was optimized over the (100)...

Plasmonic O2 Dissociation and Spillover Expedite Selective Oxidation of Primary C–H Bonds

Manipulating O2 activation via nanosynthetic chemistry is critical in many oxidation reactions central to environmental remediation and chemical synthesis. Based on a carefully-designed plasmonic Ru/TiO2–x catalyst, we first report a...

4072 Optimizing ex-vivo perfusion in Vascularized Composite Allotransplantation using Hyperosmolar solution and Electric Stimulation: Preliminary Results

OBJECTIVES/GOALS: Vascularized composite allotransplantation (VCA) restores devastating soft tissue injuries. However, graft viability may be compromised during ischemia time, thus preservation techniques continue to evolve. Here we summarize our preliminary findings from preservation techniques utilizing hyperosmolar extracellular solution (HES) and electric stimulation in a 6 hour ex-vivo perfusion model. METHODS/STUDY POPULATION: A published, MGH rodent hindlimb ex-vivo perfusion model was utilized for this project. Three baseline control elements were taken to compare our results including: a baseline muscle biopsy, harvested hindlimb preserved on ice(4°C) in static cold storage (SCS), and 6 hour perfusion (SNMP) were used to compare results of our four aims. The four aims are shown in Table 1. HES was composed of muscle media and the addition of mannitol until 3 concentrations were made: 300, 500, and 800 mOsm concentrations. In aim 4, the perfusate composition was changed to test a hyper-oncotic purfusate. After 6 hours a muscle biopsy was taken to analyze energy cofactors via liquid chromatography-mass spectrometry, referred to as energy charge. Weight gain (edema), lactate levels, oxygen consumption and energy charge (EC) were used as markers for muscle tissue viability. RESULTS/ANTICIPATED RESULTS: In Aim 1, the higher osmolarity of HES indirectly reduced weight gain but consequentially reduced the EC below 5% when compared to SCS control group. We next incorporate HES into the perfusion model, Aim 2, and noticed a diminution in weight gain. The 500 mOsm group had substantial improvement in EC, lactate production and improved oxygen exchange when compared to a controls: fresh muscle biopsy and SNMP. In Aim 3, after a 6 hour perfusion with the addition of electric stimulation, graft edema improved by 10%, EC improved by 23% and O2 dissociation was highest of all 4 aims. Consequentially, due to muscular contraction the lactate levels were highest. In Aim 4, using a hyper-oncotic perfusate, edema reduced the most during the 6 hour perfusion but revealed lower EC and similar lactate/O2 results. However when left on for 24 hours, edema was significantly higher with lactate build up, EC improved with time as well as O2 dissociation. DISCUSSION/SIGNIFICANCE OF IMPACT: Here we have shown our preliminary results comparing our known ex-vivo perfusion model to multiple hypothesis to improve VCA graft viability. These preservation techniques demonstrate promising results but further studies are ongoing to confirm this encouraging outcome.