Probing Oxide Reduction and Phase Transformations at the Au-TiO2 Interface by Vibrational Spectroscopy

By a combination of FT-NIR Raman spectroscopy, infrared spectroscopy of CO adsorption under ultrahigh vacuum conditions (UHV-IR) and Raman spectroscopy in the line scanning mode the formation of a reduced titania phase in a commercial Au/TiO2 catalyst and in freshly prepared Au/anatase catalysts was detected. The reduced phase, formed at the Au-TiO2 interface, can serve as nucleation point for the formation of stoichiometric rutile. TinO2n−1 Magnéli phases, structurally resembling the rutile phase, might be involved in this process. The formation of the reduced phase and the rutilization process is clearly linked to the presence of gold nanoparticles and it does not proceed under similar conditions with the pure titania sample. Phase transformations might be both thermally or light induced, however, the colloidal deposition synthesis of the Au/TiO2 catalysts is clearly ruled out as cause for the formation of the reduced phase

Simulation of SVPWM Based Multivariable Control Method for a DFIG Wind Energy System

This paper deals with a variable speed device toproduce electrical energy on a power network based on adoubly-fed induction machine used in generating mode(DFIG) in wind energy system by using SVPWM powertransfer matrix. This paper presents a modeling and controlapproach which uses instantaneous real and reactive powerinstead of dq components of currents in a vector controlscheme. The main features of the proposed model comparedto conventional models in the dq frame of reference arerobustness and simplicity of realization. The sequential loopclosing technique is adopted to design a multivariable controlsystem including six compensators for a DFIG wind energysystem to capture the maximum wind power and to inject therequired reactive power to the generator. In this paperSVPWM method is used for better controlling of converters.It also provides fault ride through method to protect theconverter during a fault. The time-domain simulation of thestudy system is presented by using MATLAB Simulink to testthe system robustness, to validate the proposed model and toshow the enhanced tracking capability

UHV-FTIRS and HR-XPS studies on defect-engineered metal-organic frameworks

Metall-organische Gerüstverbindungen (engl.: metal-organic frameworks, MOFs) sind poröse Materialien, bestehend aus anorganischen Metallzentren und organischen Verbindungsmolekülen. In dieser Arbeit präsentiere ich detaillierte Untersuchungen von intrinsischen Defekten in kupfer- und rutheniumbasierenden MOFs, bekannt als HKUST-1, sowie von beabsichtigt erzeugten Defekten in verschiedenen, defektmanipulierten Derivaten. Die Ultrahochvakuums-Infrarotspektroskopie und hochauflösende Röntgenphotoelektronenspektroskopie liefern detaillierte Informationen über die strukturellen und elektronischen Eigenschaften der koordinativ ungesättigten Metallzentren (engl.: coordinatively unsaturated sites, CUS) in den ursprünglichen HKUST-1-Strukturen sowie der modifizierten CUS in den defektmanipulierten MOFs. Des Weiteren stelle ich Untersuchungen in Bezug auf die reaktiven Eigenschaften mehrerer MOFs vor und diskutiere die Gründe für deren katalytische Aktivität sowie mögliche Reaktionsmechanismen

An integrated genomics approach unravels a role for micro-RNAs in EWS-FLI1 driven Ewings sarcoma pathogenesis

C

Multifunktionale, Defekt-manipulierte Metall-organische Gerüste mit Rutheniumzentren: Sorption und katalytische Eigenschaften

[DE] Das Konzept der “festen Lösungen mit gemischten Linkern” (mixed-linker solid solution concept) ist angewendet worden, um die Metallzentren des gemischtvalenten RuII/III-Analogons der bekannten Familie der [M3II,II(btc)2]-MOFs (M=Cu, Mo, Cr, Ni oder Zn; btc=Benzol-1,3,5-tricarboxylat) zu modellieren und strukturelle Defekte in das Gerüst mit teilweise fehlenden Carboxylatliganden an den Ru2-“Schaufelradeinheiten” einzubringen. Pyridin-3,5-dicarboxylat (pydc) als zweiter, Defekt-bildender Linker von ähnlicher Größe wie btc, aber geringerer Ladung führt zu einem porösen Derivat von Ru-MOF mit Eigenschaften, die sich von denen des Defekt-freien MOF unterscheiden. So bewirkt das Einbringen von pydc außer der Bildung von zusätzlichen koordinativ ungesättigten Metallzentren auch eine partielle Reduktion des Rutheniums. Die modifizierten Ru-Zentren sind für die Aktivität der “defekten” Varianten hinsichtlich dissoziativer Chemisorption von CO2, erhöhter CO-Sorption, Bildung von Ru-H-Spezies und katalytischer Hydrierung von Olefinen verantwortlich.Kozachuk, O.; Luz Minguez, I.; Llabrés I Xamena, FX.; Noei, H.; Kauer, M.; Bauke Albada, H.; Bloch, ED.... (2014). Multifunktionale, Defekt-manipulierte Metall-organische Gerüste mit Rutheniumzentren: Sorption und katalytische Eigenschaften. Angewandte Chemie. 126(27):7178-7182. doi:10.1002/ange.2013111287178718212627Furukawa, H., Cordova, K. E., O’Keeffe, M., & Yaghi, O. M. (2013). The Chemistry and Applications of Metal-Organic Frameworks. Science, 341(6149), 1230444-1230444. doi:10.1126/science.1230444Chem. Soc. Rev. 2009 38Chem. Soc. Rev. 2011 40Chem. Rev. 2012 112Corma, A., García, H., & Llabrés i Xamena, F. X. (2010). Engineering Metal Organic Frameworks for Heterogeneous Catalysis. 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Journal of the American Chemical Society, 135(31), 11465-11468. doi:10.1021/ja405078uKozachuk, O., Yusenko, K., Noei, H., Wang, Y., Walleck, S., Glaser, T., & Fischer, R. A. (2011). Solvothermal growth of a ruthenium metal–organic framework featuring HKUST-1 structure type as thin films on oxide surfaces. Chemical Communications, 47(30), 8509. doi:10.1039/c1cc11107hNoei, H., Kozachuk, O., Amirjalayer, S., Bureekaew, S., Kauer, M., Schmid, R., … Wang, Y. (2013). CO Adsorption on a Mixed-Valence Ruthenium Metal–Organic Framework Studied by UHV-FTIR Spectroscopy and DFT Calculations. The Journal of Physical Chemistry C, 117(11), 5658-5666. doi:10.1021/jp3056366Burrows, A. D. (2011). Mixed-component metal–organic frameworks (MC-MOFs): enhancing functionality through solid solution formation and surface modifications. CrystEngComm, 13(11), 3623. doi:10.1039/c0ce00568aWang, Y., Glenz, A., Muhler, M., & Wöll, C. (2009). 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Notch is active in Langerhans Cell Histiocytosis and confers pathognomonic features on dendritic cells

Langerhans cell histiocytosis (LCH) is an enigmatic disease defined by the accumulation of Langerhans-cell-like dendritic cells (DC). Here we demonstrate that LCH cells exhibit a unique transcription profile that separates them not only from plasmacytoid and myeloid DC but also from epidermal Langerhans cells, indicating a distinct DC entity. Molecular analysis revealed that isolated as well as tissue bound LCH-cells selectively express Notch ligand Jagged 2 (JAG2) and are the only DC that express both Notch ligand and its receptor. We further show that JAG2 signaling induces key LCH-cell markers in monocyte-derived DC, suggesting a functional role of Notch signaling in LCH ontogenesis. Notably, JAG2 also induced matrix-metalloproteinases 1 and 12, which are highly expressed in LCH and may account for tissue destruction in LCH lesions. This induction was selective for DC and not recapitulated in monocytes. Together these findings suggest that JAG2 mediated Notch activation confers phenotypic and functional aspects of LCH to DC. Thus, interference with Notch signaling may prove an attractive strategy to combat this disease