Polarization-Induced Hysteresis in CuCo-Doped Rare Earth Vanadates SOFC Anodes

The physical and electrochemical properties of strontium substituted cerium vandates in which a portion of the cerium cations have been substituted with transition metals (Ce0.8Sr0.1Cu0.05TM0.05VO4−0.5x, TM = Ni or Co) were investigated and their suitability for use in solid oxide fuel cell (SOFC) anodes was assessed. Upon reduction at elevated temperature, Cu and Co or Cu and Ni were exsolved from the electronically conductive Ce1−xSrxVO4 lattice to produce Cu-Ni and Cu-Co catalytic nanoparticles. The Ce0.8Sr0.1Cu0.05Co0.05VO3 appears to have high activity and relatively high hydrocarbon tolerance, suggesting that intimate contact between the exsolved Cu and Co and that the majority of the Co nanoparticles must be at least partially coated with the Cu. The electrochemical performance when used in anodes operating on hydrogen has been characterized, and the results demonstrate the exsolution of both metals from the host lattice; but observed dynamic changes in the structure of the resulting metal nanoparticles as a function of SOFC operating conditions complicate their use in SOFC anodes

MICU1 Controls Both the Threshold and Cooperative Activation of the Mitochondrial Ca(2+) Uniporter.

Mitochondrial Ca(2+) uptake via the uniporter is central to cell metabolism, signaling, and survival. Recent studies identified MCU as the uniporter\u27s likely pore and MICU1, an EF-hand protein, as its critical regulator. How this complex decodes dynamic cytoplasmic [Ca(2+)] ([Ca(2+)]c) signals, to tune out small [Ca(2+)]c increases yet permit pulse transmission, remains unknown. We report that loss of MICU1 in mouse liver and cultured cells causes mitochondrial Ca(2+) accumulation during small [Ca(2+)]c elevations but an attenuated response to agonist-induced [Ca(2+)]c pulses. The latter reflects loss of positive cooperativity, likely via the EF-hands. MICU1 faces the intermembrane space and responds to [Ca(2+)]c changes. Prolonged MICU1 loss leads to an adaptive increase in matrix Ca(2+) binding, yet cells show impaired oxidative metabolism and sensitization to Ca(2+) overload. Collectively, the data indicate that MICU1 senses the [Ca(2+)]c to establish the uniporter\u27s threshold and gain, thereby allowing mitochondria to properly decode different inputs

Phosphorus poisoning during wet oxidation of methane over Pd@CeO2/graphite model catalysts

10siThe influence of phosphorus and water on methane catalytic combustion was studied over Pd@CeO2 model catalysts supported on graphite, designed to be suitable for X-ray Photoelectron Spectroscopy/Synchrotron Radiation Photoelectron Spectroscopy (XPS/SRPES) analysis. In the absence of P, the catalyst was active for the methane oxidation reaction, although introduction of 15% H2O to the reaction mixture did cause reversible deactivation. In the presence of P, both thermal and chemical aging treatments resulted in partial loss of activity due to morphological transformation of the catalyst, as revealed by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) analysis. At 600 °C the combined presence of PO43− and water vapor caused a rapid, irreversible deactivation of the catalyst. XPS/SRPES analysis, combined with operando X-ray Absorption Near Edge Structure (XANES) and AFM measurements, indicated that water induces severe aggregation of CeO2 nanoparticles, exposure of CePO4 on the outer layer of the aggregates and incorporation of the catalytic-active Pd nanoparticles into the bulk. This demonstrates a temperature-activated process for P-poisoning of oxidation catalysts in which water vapor plays a crucial role.partially_openembargoed_20171009Monai, Matteo; Montini, Tiziano; Melchionna, Michele; Duchoň, Tomáš; Kúš, Peter; Tsud, Nataliya; Prince, Kevin C.; Matolin, Vladimir; Gorte, Raymond J.; Fornasiero, PaoloMonai, Matteo; Montini, Tiziano; Melchionna, Michele; Duchoň, Tomáš; Kúš, Peter; Tsud, Nataliya; Prince, Kevin C.; Matolin, Vladimir; Gorte, Raymond J.; Fornasiero, Paol

CNTF Mediates Neurotrophic Factor Secretion and Fluid Absorption in Human Retinal Pigment Epithelium

Ciliary neurotrophic factor (CNTF) protects photoreceptors and regulates their phototransduction machinery, but little is known about CNTF's effects on retinal pigment epithelial (RPE) physiology. Therefore, we determined the expression and localization of CNTF receptors and the physiological consequence of their activation in primary cultures of human fetal RPE (hfRPE). Cultured hfRPE express CNTF, CT1, and OsM and their receptors, including CNTFRα, LIFRβ, gp130, and OsMRβ, all localized mainly at the apical membrane. Exogenous CNTF, CT1, or OsM induces STAT3 phosphorylation, and OsM also induces the phosphorylation of ERK1/2 (p44/42 MAP kinase). CNTF increases RPE survivability, but not rates of phagocytosis. CNTF increases secretion of NT3 to the apical bath and decreases that of VEGF, IL8, and TGFβ2. It also significantly increases fluid absorption (JV) across intact monolayers of hfRPE by activating CFTR chloride channels at the basolateral membrane. CNTF induces profound changes in RPE cell biology, biochemistry, and physiology, including the increase in cell survival, polarized secretion of cytokines/neurotrophic factors, and the increase in steady-state fluid absorption mediated by JAK/STAT3 signaling. In vivo, these changes, taken together, could serve to regulate the microenvironment around the distal retinal/RPE/Bruch's membrane complex and provide protection against neurodegenerative disease

Synthesis and Stability of Pd@CeO2Core\u2013Shell Catalyst Films in Solid Oxide Fuel Cell Anodes

Submonolayer films of highly catalytically active Pd@CeO2 nanocomposites, consisting of a Pd nanoparticle core coated with a porous CeO2 shell, were deposited onto porous solid oxide fuel cell (SOFC) anodes that were functionalized with triethoxy(octyl)silane (TEOOS). SEM results show that in contrast to bare Pd particles, Pd@CeO2 particles grafted onto the surface of the ceramic anode remained highly dispersed, even after calcination in air at 1373 K. SOFC with anodes that were modified with very low loadings (0.01 wt %) of the Pd@CeO2 nanocomposites were shown to exhibit good electrochemical performance when operating with either H2 or CH4 fuels at 973 K. This performance was also maintained after annealing the anode in air at 1173 K. These results demonstrate a strategy for using very low loadings of highly active metal catalysts to enhance the activity of ceramic anodes while maintaining long-term stability

Exceptional Thermal Stability of Pd@CeO2Core\u2013Shell Catalyst Nanostructures Grafted onto an Oxide Surface

Monolayer films of highly catalytically active Pd@CeO2 core\u2013shell nanocomposites were grafted onto a planar YSZ(100) (yttria-stabilized zirconia, YSZ) single crystal support that was functionalized with a CVD-deposited layer of triethoxy(octyl)silane (TEOOS). The resulting monolayer films were found to exhibit exceptionally high thermal stability compared to bare Pd nanoparticles with the Pd@CeO2 nanostructures remaining intact and highly dispersed upon calcining in air at temperatures in excess of 1000 K. The CeO2 shells were also shown to be more easily reduced than bulk CeO2, which may partially explain their unique activity as oxidation catalysts. The use of both TEOOS and tetradecylphosphonic acid (TDPA) as coupling agents for dispersing Pd@CeO2 core\u2013shell nanocomposites onto a high surface area \u3b3-Al2O3 support is also demonstrated

Tuning the dirac point in CVD-grown graphene through solution processed n-type doping with 2-(2-methoxyphenyl)-1,3-dimethyl-2,3-dihydro-1 H-benzoimidazole

10.1021/nl303410gNano Letters1351890-1897NALE