Platinum-promoted Ga/Al2O3 as highly active, selective, and stable catalyst for the dehydrogenation of Propane

A novel catalyst material for the selective dehydrogenation of propane is presented. The catalyst consists of 1000 ppm Pt, 3 wt¿% Ga, and 0.25 wt¿% K supported on alumina. We observed a synergy between Ga and Pt, resulting in a highly active and stable catalyst. Additionally, we propose a bifunctional active phase, in which coordinately unsaturated Ga3+ species are the active species and where Pt functions as a promoter

Search for Electronic Recoil Event Rate Modulation with 4 Years of XENON100 Data

We report on a search for electronic recoil event rate modulation signatures in the XENON100 data accumulated over a period of 4 yr, from January 2010 to January 2014. A profile likelihood method, which incorporates the stability of the XENON100 detector and the known electronic recoil background model, is used to quantify the significance of periodicity in the time distribution of events. There is a weak modulation signature at a period of 431-14+16 day in the low energy region of (2.0-5.8) keV in the single scatter event sample, with a global significance of 1.9σ; however, no other more significant modulation is observed. The significance of an annual modulation signature drops from 2.8σ, from a previous analysis of a subset of this data, to 1.8σ with all data combined. Single scatter events in the low energy region are thus used to exclude the DAMA/LIBRA annual modulation as being due to dark matter electron interactions via axial vector coupling at 5.7σ

Intrinsic backgrounds from Rn and Kr in the XENON100 experiment

In this paper, we describe the XENON100 data analyses used to assess the target-intrinsic background sources radon (222Rn), thoron (220Rn) and krypton (85Kr). We detail the event selections of high-energy alpha particles and decay-specific delayed coincidences. We derive distributions of the individual radionuclides inside the detector and quantify their abundances during the main three science runs of the experiment over a period of ∼4 years, from January 2010 to January 2014. We compare our results to external measurements of radon emanation and krypton concentrations where we find good agreement. We report an observed reduction in concentrations of radon daughters that we attribute to the plating-out of charged ions on the negatively biased cathode

Adsorption and co-adsorption of CH 3 and H on flat and defective nickel (111) surfaces

We use a periodic density functional theory (DFT) code to study the adsorption of CH3 and H, as well as their co-adsorption on a Ni(111) surface with and without Ni ad-atom, at a surface coverage of 0.25 monolayer (ML). We systematically investigate the site preference for CH3 and H. Then we combine CH3 and H in many co-adsorbed configurations on both surfaces. Methyl and hydrogen adsorption on a flat Ni(111) surface favours the hollow site over the top site. The presence of a Ni ad-atom stabilizes the adsorption of CH3 better than a flat surface, while hydrogen is more stable on a flat Ni(111) surface. When H and CH3 are co-adsorbed at nearest Ni neighbours on the (111) surface, their interaction is always repulsive. However, the dissociative adsorption of CH4 is stabilised when the fragments are infinitely separated. For the co-adsorbed fragments CH3 and H, in the presence of an ad-atom, the repulsive interaction is lowered, so that the dissociative form of CH4 is locally stable

Calcium and vitamin D metabolism in granulomatous diseases.

Overproduction of the active metabolite of vitamin D 1,25-dihydroxyvitamin D (1,25(OH)2D) has been described in sarcoidosis and other granulomatous diseases. High circulating concentrations of 1,25(OH)2D lead to increased intestinal absorption of calcium, possibly to enhanced bone resorption, and may result in hypercalcaemia and/or hypercalciuria. Data obtained in vivo and in vitro demonstrated that the unregulated production of 1,25(OH)2D lies within the granulomatous tissue and is controlled by glucocorticoids. This abnormal production of 1,25(OH)2D seems to be a general phenomenon of granulomatous processes, which is not exceptional in sarcoidosis, but appears seldom in tuberculosis. These abnormalities, however, are not pathognomonic of granulomatous processes, since they have been described in other diseases such as lymphomas.Journal ArticleResearch Support, Non-U.S. Gov'tReviewSCOPUS: re.jinfo:eu-repo/semantics/publishe