Biliary reconstructive techniques and associated anatomic variants in adult living donor liver transplantations: The adult‐to‐adult living donor liver transplantation cohort study experience

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140020/1/lt24872.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/140020/2/lt24872_am.pd

Methanol and Ethanol Fuels in Solid Oxide Fuel Cells: A Thermal Imaging Study of Carbon Deposition

Near-infrared (NIR) thermal imaging is used to study anodes of anode-supported solid oxide fuel cells (SOFCs) when operating with alcohol fuels. Relative propensities for carbon formation can be determined from surface cooling under fuel flows and subsequent heating under oxidizing conditions at temperatures between 700 and 800 °C. Ethanol forms considerable amounts of carbon at all temperatures and voltages studied as evidenced by substantial cooling related to carbon reactions and heating under oxidizing conditions. Methanol operation depends greatly on cell temperature and voltage. At 700 °C, temperature changes resemble those with ethanol, suggesting carbon deposition is occurring. At 800 °C, there is less cooling, which indicates that the oxide flux at higher polarizations mitigates the effects of endothermic carbon reactions. Under oxidizing conditions after fuel exposure, the small observed temperature increase demonstrates that little carbon is formed. At 750 °C the cooling depends on voltage, revealing a set of conditions where cooling from endothermic reactions and heating from exothermic reactions are balanced. The results show that while dry ethanol is not a clean fuel under any of our conditions, methanol can be at higher temperatures. NIR thermal imaging proves a valuable stand-off technique for identifying cell deterioration in situ, with potential for process monitoring in operating SOFCs

Identification of a Methane Oxidation Intermediate on Solid Oxide Fuel Cell Anode Surfaces with Fourier Transform Infrared Emission

Fuel interactions on solid oxide fuel cell (SOFC) anodes are studied with in situ Fourier transform infrared emission spectroscopy (FTIRES). SOFCs are operated at 800 °C with CH₄ as a representative hydrocarbon fuel. IR signatures of gas-phase oxidation products, CO_2(g) and CO_(g), are observed while cells are under load. A broad feature at 2295 cm^–1 is assigned to CO₂ adsorbed on Ni as a CH₄ oxidation intermediate during cell operation and while carbon deposits are electrochemically oxidized after CH₄ operation. Electrochemical control provides confirmation of the assignment of adsorbed CO₂. FTIRES has been demonstrated as a viable technique for the identification of fuel oxidation intermediates and products in working SOFCs, allowing for the elucidation of the mechanisms of fuel chemistry

ULTRAFAST SPECTROSCOPY OF TRANSITION METAL NANORODS

Author Institution: Chemistry Division, Naval Research Laboratory, Washington, DC 20375; Chemistry Department, United States Naval Academy, Annapolis, MD 21402Nanorods composed of transition metals were fabricated and studied by ultrafast transient absorption and static UV vis-NIR spectroscopy. Platinum, iron, cobalt, silver and rhodium high-aspect ratio nanorods were made by electrodeposition in 6 $\mu$m thick, polycarbonate templates. The nanorods were produced with aqueous plating solutions in templates with nominal pore sizes of 10 and 30 nm, resulting in rods with ~40 and ~60 nm diameters as indicated by SEM measurements. Aluminum nanorods, which cannot be electrodeposited using aqueous solutions, were fabricated in an ionic liquid-based Al plating solution. Transmission spectra show that the nanorods of each metal have a transverse surface plasmon resonance band in the 400-600 nm range and a longitudinal band in the mid-infrared. Ultrafast transient absorption measurement with 400 nm pump and 800 nm probe are used to characterize electron-phonon coupling times and coherent acoustic breathing mode oscillations. The oscillations occur on a 10-40 ps timescale and are consistent with classical expectations for acoustic breathing mode periods based on the nanorod diameters and the bulk longitudinal speed of sound for each metal. Results are consistent with those previously reported for other metals (gold, nickel, and palladium).(1) Furthermore, the dynamics for these metals are similar to those observed for smaller nanoparticles and nanorods. (1) G.M. Sando, A.D. Berry, and J.C. Owrutsky J. Chem. Phys. 127(7), 074705 August 200

Toward a Working Mechanism of Fuel Oxidation in SOFCs: In Situ Optical Studies of Simulated Biogas and Methane

Solid-oxide fuel cells (SOFCs) have potential as highly efficient, clean, and sustainable electricity sources. However, the current, limited state of understanding of the complex electrochemical processes that occur at the anode in these systems, particularly those that lead to anode carbon formation and degradation, are roadblocks to effective cell design and operation. A suite of noninvasive, in situ optical techniques has been developed to help identify these processes. Vibrational Raman spectroscopy, Fourier-transform infrared emission spectroscopy (FTIRES), and near-infrared thermal (NIR) imaging, along with electrochemical measurements, provide surface and gas-phase molecular-specific diagnostics with the requisite temporal, spatial, and thermal resolution to correlate in operando observations with model chemical mechanisms associated with oxidation and carbon formation on Ni-based, anode-supported cells. This present work expands upon earlier in operando studies to fully assess the performance of commercially available Ni-YSZ anode SOFCs from 700 to 800 °C and to provide a more comprehensive description of the anode chemistry involved. Methane and simulated biogas (BG) are used as fuel. Raman measurements show that carbon grows minimally only at the lower operational temperatures for BG; however under methane, carbon formation occurs at all temperatures. Subsequent electrochemical oxidation of deposited carbon revealed that carbon formation under both fuels varies differently as a function of temperature. FTIRES measurements show that CO_<i>x</i> constituents increase with cell polarization only under methane fuel; this effect changes with temperature. NIR imaging indicates that the Ni anode surface cools significantly when cells are operated at 800 °C relative to 700 °C under BG, and only minimal cooling is observed when operating with methane

The use of thromboelastography to assess post-operative changes in coagulation and predict graft function in renal transplantation.

BackgroundEnd stage renal disease (ESRD) is associated with elevated fibrinogen levels and fibrinolysis inhibition. However, there is a paucity of data on how renal transplantation impacts coagulation. we hypothesize that renal transplantation recipients with good functioning grafts will have improved fibrinolytic activity following surgery.MethodsKidney recipients were analyzed pre-operatively and on post-operative day 1(POD1) using three different TEG assays with and without two concentration of tissue-plasminogen activator (t-PA). TEG indices and percent reduction in creatinine from pre-op to POD1 were measured, with &gt;50% defining "good" graft function. Follow up was done at 6, 12, and 24 months.ResultsPercent lysis(LY30) on POD1 the t-PA TEG was significantly correlated to change creatinine from pre-op to POD-1(p&nbsp;=&nbsp;0.006). A LY30&nbsp;≥&nbsp;23% was associated with good early graft function, and lower creatinine at 24-months(p&nbsp;=&nbsp;0.028) compared to recipients with low POD1 LY30.ConclusionsPost-operative tPA-TEG LY30 is associated with favorable early and late outcomes in kidney transplant