248 research outputs found

    Intermolecular interactions in N-(ferrocenylmethyl)anthracene-9-carboxamide

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    The title compound, [Fe(C₅H₅)(C₂₁H₁₆NO)], was synthesized from the coupling reaction of anthracene-9-carboxylic acid and ferrocenylmethylamine. The ferrocenyl (Fc) group and the anthracene ring system both lie approximately orthogonal to the amide moiety. An amide-amide interaction (along the a axis) is the principal interaction [N...O = 2.910 (2) Å]. A C-H...π(arene) interaction [C...centroid = 3.573 (2) Å] and a C-H...O interaction [C...O = 3.275 (3) Å] complete the hydrogen bonding; two short (Fc)C...C(anthracene) contacts are also present

    Preparation of biodegradable functionalized polyesters aimed to be used as surgical adhesives

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    The study and development of new biocompatible materials to be applied as UV-curable adhesives is extremely important to grant the preparation of matrices with suitable mechanical, biological and thermal properties with a fast curing rate. Herein, photocrosslinkable biodegradable copolymers composed of unsaturated polyesters (UP) and lactic acid oligomers functionalized with 2-isocyanatoethyl methacrylate (IEMA) were produced. Henceforth, three different stoichiometric proportions were tested, which, after the addition of a biocompatible photoinitiator (IrgacureÂź 2959), resulted in flexible, resistant and uniform matrices after 2 minutes and 30 seconds of crosslinking. The synthesized materials were then further characterized in terms of chemical composition and thermal/mechanical behaviour. The gel content, dynamic contact angles, water sorption capacity and hydrolytic degradation were also assessed. The biocompatibility and antibacterial activity of the produced materials was also evaluated. Taking into account all the data obtained, it may be concluded that the new synthesized biodegradable bioadhesives present promising properties to be used as surgical adhesives.info:eu-repo/semantics/acceptedVersio

    Effect of the Interfacial Water Structure on the Hydrogen Evolution Reaction on Pt(111) Modified with Different Nickel Hydroxide Coverages in Alkaline Media

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    The hydrogen evolution reaction (HER) constitutes one of the most important reactions in electrochemistry because of the value of hydrogen as a vector for energy storage and transport. Therefore, understanding the mechanism of this reaction in relation to its pH dependence is of crucial importance. While the HER on Pt(111) works efficiently in acid media, in alkaline media, the reaction is impeded and considerably larger applied overpotentials are necessary. The presence of Ni(OH)2 adsorbed on Pt(111) has been demonstrated to highly improve the rate of hydrogen evolution, decreasing the overpotential of this reaction in comparison to acid media. The way low coverages of Ni(OH)2 on the Pt surface improve HER is still under discussion. In this work, we have prepared different Ni(OH)2 coverages on Pt(111) to check how Ni(OH)2 deposited on Pt(111) influences the HER rate. To this end, the Ni(OH)2–Pt(111)|0.1 M NaOH interface was characterized with cyclic voltammetry, CO displacement technique, and Fourier transform infrared-reflection absorption spectroscopy. On the basis of the proposal made by Ledezma-Yanez et al. [Nature Energy 2017, 2, 17031] to explain the HER in alkaline media, we also studied the effect of the different Ni(OH)2 coverages on the electric field using the laser-induced temperature jump technique. This technique revealed that introduction of nickel adlayers on the surface decreases the ordering of the water network at the interphase, a fact that has relevant implications for the HER mechanism.The authors thankfully acknowledge financial support from the MICINN (Spain) through project CTQ2016-76221-P. P. Sebastian acknowledges to MECD the award of a FPU grant. F.J.S. acknowledges to Ministerio de Economia, Industria y Competitividad (PEJ-2014-A-57942/PEJ-2014-P-00295)

    Spectra, signless Laplacian and Laplacian spectra of complementary prisms of graphs

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    The complementary prism GG‟ of a graph G is obtained from the disjoint union of G and its complement G‟ by adding an edge for each pair of vertices (v,vâ€Č), where v is in G and its copy vâ€Č is in G‟. The Petersen graph C5C5‟ and, for n≄2, the corona product of Kn and K1 which is KnKn‟ are examples of complementary prisms. This paper is devoted to the computation of eigenpairs of the adjacency, signless Laplacian and Laplacian matrices of a complementary prism GG‟ in terms of the eigenpairs of the corresponding matrices of G. Particular attention is given to the complementary prisms of regular graphs. Furthermore, Petersen graph is shown to be the unique complementary prism which is a strongly regular graph

    Interfacial water reorganization as a pH-dependent descriptor of the hydrogen evolution rate on platinum electrodes

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    Hydrogen evolution on platinum is a key reaction for electrocatalysis and sustainable energy storage, yet its pH-dependent kinetics are not fully understood. Here we present a detailed kinetic study of hydrogen adsorption and evolution on Pt(111) in a wide pH range. Electrochemical measurements show that hydrogen adsorption and hydrogen evolution are both slow in alkaline media, consistent with the observation of a shift in the rate-determining step for hydrogen evolution. Adding nickel to the Pt(111) surface lowers the barrier for hydrogen adsorption in alkaline solutions and thereby enhances the hydrogen evolution rate. We explain these observations with a model that highlights the role of the reorganization of interfacial water to accommodate charge transfer through the electric double layer, the energetics of which are controlled by how strongly water interacts with the interfacial field. The model is supported by laser-induced temperature-jump measurements. Our model sheds light on the origin of the slow kinetics for the hydrogen evolution reaction in alkaline media.This work was supported by a TOP grant from the Netherlands Organization for Scientific Research (NWO). Support from MINECO (Spain) through project CTQ2013-44083-P is acknowledged

    Access to infertility consultations: what women tell us about it?

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    The main objective of the present paper is to evaluate the perception of women concerning the barriers and access to infertility consultations. Socio cultural and economic access to infertility consultations is detached and three municipalities of the northwest of Portugal were chosen as an example of a peripheral country. A quantitative/qualitative study was done with 60 women. Three dimensions were evaluated: geographic and structural and functional access; economic access; and sociocultural access. The main barriers were mainly identified in the last two dimensions. The economic access was the less well evaluated by women being the cost of treatment (medication, and concentration of costs in a short period) difficult to bear. This can justify a greater involvement of the Portuguese Government, by developing policies for the reimbursement of part of the costs. Also, some changes in structural and functional access must be done with special regard to the separation of the infertility consultations from the reproductive medicine section. The setting of the teams, with a follow-up by the same team of health professionals is also needed

    Measurement of the Bs0→J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction

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    The Bs0→J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction is measured in a data sample corresponding to 0.41fb−1fb^{-1} of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the sin2ÎČ\beta measurement from B0→J/ψKS0B^0\to J/\psi K_S^0 The time-integrated branching fraction is measured to be BF(Bs0→J/ψKS0)=(1.83±0.28)×10−5BF(B_s^0\to J/\psi K_S^0)=(1.83\pm0.28)\times10^{-5}. This is the most precise measurement to date

    Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays

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    Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201

    Model-independent search for CP violation in D0→K−K+π−π+ and D0→π−π+π+π− decays

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    A search for CP violation in the phase-space structures of D0 and View the MathML source decays to the final states K−K+π−π+ and π−π+π+π− is presented. The search is carried out with a data set corresponding to an integrated luminosity of 1.0 fb−1 collected in 2011 by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. For the K−K+π−π+ final state, the four-body phase space is divided into 32 bins, each bin with approximately 1800 decays. The p-value under the hypothesis of no CP violation is 9.1%, and in no bin is a CP asymmetry greater than 6.5% observed. The phase space of the π−π+π+π− final state is partitioned into 128 bins, each bin with approximately 2500 decays. The p-value under the hypothesis of no CP violation is 41%, and in no bin is a CP asymmetry greater than 5.5% observed. All results are consistent with the hypothesis of no CP violation at the current sensitivity
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