Pertussis toxin-dependent and -independent hormonal effects on cultured renal epithelioid cells

AbstractThe present study has been performed to test for the involvement of pertussis toxin-sensitive GTP-binding proteins (G-proteins) in the cellular transduction of hormone-induced activation of potassium channels. In Madin Darby canine kidney (MDCK) cells, a permanent cell line from dog kidney, epinephrine, acetylcholine, bradykinin, serotonin and ATP hyperpolarize the cell membrane by activation of potassium channels. In cells pretreated with pertussis toxin the hyperpolarizations elicited by either acetylcholine or serotonin are completely abolished; that following epinephrine is blunted and only transient. The hyperpolarizing effects of ATP or bradykinin are not affected by pertussis toxin. Thus, in MDCK cells both pertussis toxin-dependent and -independent mechanisms operate in parallel to enhance the potassium conductance of the cell membrane

Liquid-Phase Quasi-Epitaxial Growth of Highly Stable, Monolithic UiO-66-NH₂ MOF thin Films on Solid Substrates

High quality, monolithic UiO‐66‐NH2 thin films on diverse solid substrates have been prepared via a low temperature liquid phase epitaxy method. The achievement of continuous films with low defect densities and great stability against high temperatures and hot water is proven, clearly outperforming other reported types of MOF thin films

Anomalous Surface Compositions of Stoichiometric Mixed Oxide Compounds

The surface compositions of bulk mixed metal oxides stoichiometric vanadate and molybdate compounds have been systematically examined, for the first time, by combined synchroton-based depth-resolved XPS profile analysis, conventional XPS and LEIS spectroscopy. The outer surfaces of many, but not all, of the bulk mixed vanadates and molybdates tend to be enriched with surface VOx and MoOx species approaching monolayer coverage. Furthermore, this surface enrichment phenomenon can be dramatically enhanced in the presence of minor amount of alkali impurities. These new findings have significant implications for the fundamental understanding of how bulk mixed oxide materials function in numerous technical applications.Fil: Merzlikin, Sergiy V. . Ruhr-Universitt Bochum, Lehrstuhl fr Technische Chemie; AlemaniaFil: Tolkachev, Nikolay N. . Russian Academy of Sciences, N. D. Zelinsky Institute of Organic Chemistry; RusiaFil: Briand, Laura Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Strunskus,Thomas . Ruhr-Universitt Bochum, Lehrstuhl Physikalische Chemie; AlemaniaFil: Wöll, Christof. Ruhr-Universitt Bochum, Lehrstuhl Physikalische Chemie; AlemaniaFil: Wachs, Israel E.. Lehigh University Bethlehem, Department of Chemical Engineering, Operando Molecular Spectroscopy and Catalysis Laboratory; Estados UnidosFil: Grüenert, Wolfgang . Ruhr-Universitt Bochum, Lehrstuhl fr Technische Chemie; Alemani

Anomalous Surface Compositions of Stoichiometric Mixed Oxide Compounds

The surface compositions of bulk mixed metal oxides stoichiometric vanadate and molybdate compounds have been systematically examined, for the first time, by combined synchroton-based depth-resolved XPS profile analysis, conventional XPS and LEIS spectroscopy. The outer surfaces of many, but not all, of the bulk mixed vanadates and molybdates tend to be enriched with surface VOx and MoOx species approaching monolayer coverage. Furthermore, this surface enrichment phenomenon can be dramatically enhanced in the presence of minor amount of alkali impurities. These new findings have significant implications for the fundamental understanding of how bulk mixed oxide materials function in numerous technical applications.Fil: Merzlikin, Sergiy V. . Ruhr-Universitt Bochum, Lehrstuhl fr Technische Chemie; AlemaniaFil: Tolkachev, Nikolay N. . Russian Academy of Sciences, N. D. Zelinsky Institute of Organic Chemistry; RusiaFil: Briand, Laura Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Strunskus,Thomas . Ruhr-Universitt Bochum, Lehrstuhl Physikalische Chemie; AlemaniaFil: Wöll, Christof. Ruhr-Universitt Bochum, Lehrstuhl Physikalische Chemie; AlemaniaFil: Wachs, Israel E.. Lehigh University Bethlehem, Department of Chemical Engineering, Operando Molecular Spectroscopy and Catalysis Laboratory; Estados UnidosFil: Grüenert, Wolfgang . Ruhr-Universitt Bochum, Lehrstuhl fr Technische Chemie; Alemani

Anomalous Surface Compositions of Stoichiometric Mixed Oxide Compounds

The surface compositions of bulk mixed metal oxides stoichiometric vanadate and molybdate compounds have been systematically examined, for the first time, by combined synchroton-based depth-resolved XPS profile analysis, conventional XPS and LEIS spectroscopy. The outer surfaces of many, but not all, of the bulk mixed vanadates and molybdates tend to be enriched with surface VOx and MoOx species approaching monolayer coverage. Furthermore, this surface enrichment phenomenon can be dramatically enhanced in the presence of minor amount of alkali impurities. These new findings have significant implications for the fundamental understanding of how bulk mixed oxide materials function in numerous technical applications.Fil: Merzlikin, Sergiy V. . Ruhr-Universitt Bochum, Lehrstuhl fr Technische Chemie; AlemaniaFil: Tolkachev, Nikolay N. . Russian Academy of Sciences, N. D. Zelinsky Institute of Organic Chemistry; RusiaFil: Briand, Laura Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Strunskus,Thomas . Ruhr-Universitt Bochum, Lehrstuhl Physikalische Chemie; AlemaniaFil: Wöll, Christof. Ruhr-Universitt Bochum, Lehrstuhl Physikalische Chemie; AlemaniaFil: Wachs, Israel E.. Lehigh University Bethlehem, Department of Chemical Engineering, Operando Molecular Spectroscopy and Catalysis Laboratory; Estados UnidosFil: Grüenert, Wolfgang . Ruhr-Universitt Bochum, Lehrstuhl fr Technische Chemie; Alemani

Probing the Water Stability Limits and Degradation Pathways of Metal-Organic Frameworks (MOFs)

A comprehensive model to describe the water stability of prototypical metal–organic frameworks (MOFs) is derived by combining different types of theoretical and experimental approaches. The results provide an insight into the early stages of water-triggered destabilization of MOFs and allow detailed pathways to be proposed for the degradation of different MOFs under aqueous conditions. The essential elements of the approach are computing the pKa values of coordinated water molecules and geometry relaxations. Variable-temperature and pH infrared spectroscopy techniques are used to corroborate the main findings. The model developed herein helps to explain stability limits observed for several prototypical MOFs, including MOF-5, HKUST-1, UiO-66, and MIL-101-Cr, in aqueous solutions, and thus, provides an insight into the possible degradation pathways in acidic and basic environments. The formation of a metal hydroxide through the autoprotolysis of metal-coordinated water molecules and the strength of carboxylate–metal interactions are suggested to be two key players that govern stability in basic and acidic media, respectively. The methodology presented herein can effectively guide future efforts, which are especially significant for in silico screening, for developing novel MOFs with enhanced aqueous stability