970 resultados para Ag additions
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A review of Pharmacotheraphy of obesity
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*Partially supported by NATO.
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We have previously described ProxiMAX, a technology that enables the fabrication of precise, combinatorial gene libraries via codon-by-codon saturation mutagenesis. ProxiMAX was originally performed using manual, enzymatic transfer of codons via blunt-end ligation. Here we present Colibra™: an automated, proprietary version of ProxiMAX used specifically for antibody library generation, in which double-codon hexamers are transferred during the saturation cycling process. The reduction in process complexity, resulting library quality and an unprecedented saturation of up to 24 contiguous codons are described. Utility of the method is demonstrated via fabrication of complementarity determining regions (CDR) in antibody fragment libraries and next generation sequencing (NGS) analysis of their quality and diversity.
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Semihydrogenation of acetylene in an ethylene-rich stream is an industrially important process. Conventional supported monometallic Pd catalysts offer high acetylene conversion, but they suffer from very low selectivity to ethylene due to overhydrogenation and the formation of carbonaceous deposits. Herein, a series of Ag alloyed Pd single-atom catalysts, possessing only ppm levels of Pd, supported on silica gel were prepared by a simple incipient wetness coimpregnation method and applied to the selective hydrogenation of acetylene in an ethylene-rich stream under conditions close to the front-end employed by industry. High acetylene conversion and simultaneous selectivity to ethylene was attained over a wide temperature window, surpassing an analogous Au alloyed Pd single-atom system we previously reported. Restructuring of AgPd nanoparticles and electron transfer from Ag to Pd were evidenced by in situ FTIR and in situ XPS as a function of increasing reduction temperature. Microcalorimetry and XANES measurements support both geometric and electronic synergetic effects between the alloyed Pd and Ag. Kinetic studies provide valuable insight into the nature of the active sites within these AgPd/SiO2 catalysts, and hence, they provide evidence for the key factors underpinning the excellent performance of these bimetallic catalysts toward the selective hydrogenation of acetylene under ethylene-rich conditions while minimizing precious metal usage.
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Scanning tunneling microscopy, temperature-programmed reaction, near-edge X-ray absorption fine structure spectroscopy, and density functional theory calculations were used to study the adsorption and reactions of phenylacetylene and chlorobenzene on Ag(100). In the absence of solvent molecules and additives, these molecules underwent homocoupling and Sonogashira cross-coupling in an unambiguously heterogeneous mode. Of particular interest is the use of silver, previously unexplored, and chlorobenzene—normally regarded as relatively inert in such reactions. Both molecules adopt an essentially flat-lying conformation for which the observed and calculated adsorption energies are in reasonable agreement. Their magnitudes indicate that in both cases adsorption is predominantly due to dispersion forces for which interaction nevertheless leads to chemical activation and reaction. Both adsorbates exhibited pronounced island formation, thought to limit chemical activity under the conditions used and posited to occur at island boundaries, as was indeed observed in the case of phenylacetylene. The implications of these findings for the development of practical catalytic systems are considered.
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We conducted a low-level phosphorus (P) enrichment study in two oligotrophic freshwater wetland communities (wet prairies [WP] and sawgrass marsh [SAW]) of the neotropical Florida Everglades. The experiment included three P addition levels (0, 3.33, and 33.3 mg P m−2 month−1), added over 2 years, and used in situ mesocosms located in northeastern Everglades National Park, Fla., USA. The calcareous periphyton mat in both communities degraded quickly and was replaced by green algae. In the WP community, we observed significant increases in net aboveground primary production (NAPP) and belowground biomass. Aboveground live standing crop (ALSC) did not show a treatment effect, though, because stem turnover rates of Eleocharis spp., the dominant emergent macrophyte in this community, increased significantly. Eleocharis spp. leaf tissue P content decreased with P additions, causing higher C:P and N:P ratios in enriched versus unenriched plots. In the SAW community, NAPP, ALSC, and belowground biomass all increased significantly in response to P additions. Cladium jamaicense leaf turnover rates and tissue nutrient content did not show treatment effects. The two oligotrophic communities responded differentially to P enrichment. Periphyton which was more abundant in the WP community, appeared to act as a P buffer that delayed the response of other ecosystem components until after the periphyton mat had disappeared. Periphyton played a smaller role in controlling ecosystem dynamics and community structure in the SAW community. Our data suggested a reduced reliance on internal stores of P by emergent macrophytes in the WP that were exposed to P enrichment. Eleocharis spp. rapidly recycled P through more rapid aboveground turnover. In contrast, C. jamaicense stored added P by initially investing in belowground biomass, then shifting growth allocation to aboveground tissue without increasing leaf turnover rates. Our results suggest that calcareous wetland systems throughout the Caribbean, and oligotrophic ecosystems in general, respond rapidly to low-level additions of their limiting nutrient.
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Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.
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Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.
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A paradigma kifejezést Thomas Kuhn honosította meg a tudományfilozófiában: így nevezte el azt a sajátos szemléletmódot, ahogyan egy kutatási irányzat rátekint vizsgálata tárgyára. Azonos paradigmát használó kutatók hasonló kérdésekre keresik a választ, hasonló módszereket és fogalmakat alkalmaznak. A szerző 1999-ben publikált cikkében vezette be a "rendszerparadigma" kifejezést, amely a társadalomban működő rendszereket helyezi a vizsgálat középpontjába. A tanulmány a posztszocialista átalakulás során szerzett tapasztalatok alapján fejleszti tovább a korábbi cikkben kifejtett elméleti gondolatokat. Az első rész a szocialista és a kapitalista rendszert hasonlítja össze; leírja fő jellemzőiket, majd megállapítja, hogy Észak-Korea és Kuba kivételével az egykori szocialista országokban meghonosodott a kapitalista rendszer. A második rész a politikai-kormányzati formák szerint tipologizálja a kapitalizmus változatait. Három markáns típust különböztet meg: a demokráciát, az autokráciát és a diktatúrát. Huntington a demokratizálás harmadik hullámáról írt. A tanulmány arra a következtetésre jut, hogy ez a hullám elapadt, a 47 posztszocialista ország lakosságának mindössze egytizede él demokráciában, a többiben autokrácia vagy diktatúra uralkodik. A harmadik rész Magyarországra alkalmazza a kialakított fogalmi és elemzési apparátust: itt kapitalizmus van, a politikai-kormányzati forma autokrácia - lényeges közös jellemzők mutathatók ki más kapitalista országokkal, illetve más autokráciákkal. Ez összefér azzal a felismeréssel, hogy egyes - nem alapvető jelentőségű - vonások egyediek, "hungarikumok", különböznek minden más ország tulajdonságaitól. _____ The expression paradigm, introduced into the philosophy of science by Thomas Kuhn for the way a research trend views the subject examined, denotes a case where researchers pursue similar questions by similar methods with similar concepts. The author introduced the expression system paradigm" in a 1999 article centred on the systems operating in society. This paper takes those theoretical ideas further, based on experience in the post-socialist transformation. The first part compares the socialist and capitalist systems and their main features, establishing that all former socialist countries but North Korea and Cuba have embraced the capitalist system. The second adds a typology of the varieties of capitalism by politico-governmental form, marking three types: democracy, autocracy and dictatorship. Huntington writes of a third wave of democratization, which this study concludes has ceased. Democracy reigns in only 10 per cent of the 47 post-socialist countries, autocracy or dictatorship in the others. The third part applies this conceptual and analytical framework to Hungary, where capitalism prevails, with autocracy as its politico-governmental form. It shows strongly similar features to other capitalist countries and other autocracies. This is compatible with recognizing that some features of less than fundamental importance are specific to Hungary and differ from those elsewhere.
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This document focuses the projects developed during two independent internships, which were carried out at Inficon AG and PT Inovação & Sistemas. Since the research areas of both internships are unrelated, individual abstracts are presented.
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The majority of electrode materials in batteries and related electrochemical energy storage devices are fashioned into slurries via the addition of a conductive additive and a binder. However, aggregation of smaller diameter nanoparticles in current generation electrode compositions can result in non-homogeneous active materials. Inconsistent slurry formulation may lead to inconsistent electrical conductivity throughout the material, local variations in electrochemical response, and the overall cell performance. Here we demonstrate the hydrothermal preparation of Ag nanoparticle (NP) decorated α-AgVO3 nanowires (NWs) and their conversion to tunnel structured β-AgVO3 NWs by annealing to form a uniform blend of intercalation materials that are well connected electrically. The synthesis of nanostructures with chemically bound conductive nanoparticles is an elegant means to overcome the intrinsic issues associated with electrode slurry production, as wire-to-wire conductive pathways are formed within the overall electrode active mass of NWs. The conversion from α-AgVO3 to β-AgVO3 is explained in detail through a comprehensive structural characterization. Meticulous EELS analysis of β-AgVO3 NWs offers insight into the true β-AgVO3 structure and how the annealing process facilitates a higher surface coverage of Ag NPs directly from ionic Ag content within the α-AgVO3 NWs. Variations in vanadium oxidation state across the surface of the nanowires indicate that the β-AgVO3 NWs have a core–shell oxidation state structure, and that the vanadium oxidation state under the Ag NP confirms a chemically bound NP from reduction of diffused ionic silver from the α-AgVO3 NWs core material. Electrochemical comparison of α-AgVO3 and β-AgVO3 NWs confirms that β-AgVO3 offers improved electrochemical performance. An ex situ structural characterization of β-AgVO3 NWs after the first galvanostatic discharge and charge offers new insight into the Li+ reaction mechanism for β-AgVO3. Ag+ between the van der Waals layers of the vanadium oxide is reduced during discharge and deposited as metallic Ag, the vacant sites are then occupied by Li+.