Microstructural and in vitro characterisation of 45S5 bioactive glass coatings deposited by Solution Precursor Plasma Spraying (SPPS)

The present work focused on the development of bioactive glass coatings employing Solution Precursor Plasma Spraying. Precursors of SiO2, CaO, Na2O and P2O5 were mixed in distilled water to prepare concentrated solutions with a composition close to the 45S5 bioactive glass. Solutions were rheologically characterised to assess their stability with time and deposited onto AISI type 304 stainless steel to develop coatings under different parameters related to the thermal spraying technique. The effect of these parameters on coatings microstructure was studied by scanning electron microscopy. Coatings were also analysed by X–ray diffraction and scratch test to complete the microstructural characterization. Moreover, coatings bioactivity was evaluated by immersing them in Simulated Body Fluid. The study showed that using short spraying distances and low argon flow rates, gave rise to the typical microstructure derived from liquid feedstocks whereas some crystallization associated to the long spray distance used occurred. Scratch test revealed that the resulting coating possessed good mechanical properties when compared with similar coatings obtained by other plasma spraying techniques. Moreover, the obtained coating could develop an hydroxycarbonate apatite layer when in contact with Simulated Body Fluid as demonstrated by scanning electron microscopy, X–ray diffraction and Fourier transform infrared spectroscopy

Solution precursor plasma spraying (SPPS): a novel and simple process to obtain bioactive glass coatings

This research addresses the use of an emerging plasma spray technique known as SPPS (Solution Precursor Plasma Spraying) to obtain bioactive glass coatings. In SPPS, the feedstock is a sol precursor of the bioactive glass instead of glass particles. Precursor feedstock composition (presence or not of acid catalyst), plasma torch enthalpy and stand-off distance of the spraying process have been varied to produce bioactive glass coatings of nominally 45S5 composition. A good quality coating was obtained when catalyst (0.2 M acid nitric) was used in the precursor and the plasma spraying took place with shorter stand-off distance and higher plasma enthalpy. Bioactivity in Simulated Body Fluid test was confirmed and an effect of the coating interconnected porosity to enhance bioactivity was observed

La neurofilmologie. Une théorie pragmatique de l’audiovisuel en dialogue avec les sciences neurocognitives

The paper introduces the neurofilmological approach to moving images specifying its epistemological and methodological base

Estudio in vitro de recubrimientos de vidrio bioactivo depositados mediante proyección térmica por plasma atmosférico

This research has addressed a complete study of the bioactivity of bioactive glass coatings obtained by atmospheric plasma spraying. The coatings have been characterized in terms of microstructure, adhesion, crystalline phases and bioactivity. Hydroxycarbonate apatite formation was also monitored following a standard protocol and the in vitro cell response was evaluated by human osteoblast-like cells (MG-63 cells) incubation. The obtained coatings shown a microstructure typical of glass coatings. A simulated body fluid test proved that coatings are capable of developing a surface layer of hydroxycarbonate apatite whereas the appearance of this phase takes place at a longer time than that observed for the powder feedstock. Cell-culture test showed multidirectional growth of MG-63 cells which promoted good contact between cells and the surface of the coating. This study has confirmed a positive effect of the coatings in terms of surface bioactivity and, more interestingly, it has proven an adequate cell-material interaction on the coating surface.Este trabajo ha abordado un estudio completo de la bioactividad de recubrimientos de vidrio bioactivo depositados mediante proyección térmica por plasma atmosférico. Se han caracterizado la microestructura, la adherencia, las fases cristalinas y la bioactividad de los recubrimientos obtenidos. También se ha estudiado la formación de hidroxiapatita carbonatada siguiendo un protocolo estándar y se ha evaluado la respuesta in vitro de los recubrimientos mediante su incubación con osteoblastos humanos (células MG-63). Los recubrimientos obtenidos han mostrado una microestructura típica de recubrimientos de vidrio. Tras la inmersión en fluido biológico simulado, se ha comprobado que el recubrimiento es capaz de desarrollar una capa superficial de hidroxiapatita carbonatada, aunque la velocidad de aparición de esta capa es menor que la observada para el polvo de vidrio de partida. El ensayo de cultivo celular ha mostrado un crecimiento multidireccional de las células MG-63, dando lugar a un buen contacto entre las células y la superficie del recubrimiento. Este estudio ha confirmado un efecto positivo de los recubrimientos en términos de bioactividad de la superficie y, lo que es más interesante, ha demostrado una adecuada interacción célula-material sobre la superficie del recubrimiento

Debt in the 1990s

Debt

Planck-Scale Physics and Neutrino Masses

We discuss gravitationally induced masses and mass splittings of Majorana, Zeldovich-Konopinski-Mahmoud and Dirac neutrinos. Among other implications, these effects can provide a solution of the solar neutrino puzzle. In particular, we show how this may work in the 17 keV neutrino picture.Comment: 10 pages, IC/92/79, SISSA-83/92/EP, LMU-04/92 (the preprint number has been corrected; no other changes

Comparison of in vitro and in situ plankton production determinations

Plankton production was measured using 8 techniques at 4 stations in the Celtic Sea, North Atlantic Ocean, in April 2002. Primary production (PP) was derived from 14C incorporation into particulate carbon after 24 h simulated in situ, PP(14CSIS), and 2 h photosynthesis-irradiance incubations, PP(14CPUR), and from 2 published satellite algorithms, PP(VGPM) and PP (M91). Gross production (GP) was calculated from O2 evolution, GP(O2), and 18O enrichment of dissolved O 2, GP(18O), after 24 h simulated in situ incubations, and from in situ active fluorescence measured by fast repetition rate fluorometry (FRRF). Net community production (NCP) was determined from changes in in situ dissolved oxygen, NCP(?O2), and from changes in oxygen during 24 h simulated in situ incubations, NCP(O2). Dark community respiration (DCR) was derived from changes in oxygen during a 24 h dark incubation, DCR(O2), and daily oxygen uptake, DOU(18O, O2), was calculated from the difference between GP(18O) and NCP(O2). Three stations were dominated by picoautotrophs and the fourth station was dominated by diatoms. While most of the comparisons between techniques fell within previously published ranges, 2 anomalies occurred only at the diatom-dominated station. Rates of PP(14CPUR) were oxygen uptake in the dark. The low rates of PP( 14CPUR) in relation to PP(14CSIS) may have resulted from the heterogeneous nature of the bloom and differences in sampling time. However, it is also possible that dissolved organic material (DOM) released by the stressed diatom population restricted the diffusion of 14C into the cells, thereby causing a greater underestimate of PP by techniques using short incubations. The significantly higher rates of oxygen uptake in the light are difficult to reconcile, and we do not know whether the light enhanced oxygen uptake was directly linked to carbon fixation. However, the release of DOM may also have provided substrate for enhanced respiration in the light. These anomalies were only revealed through the concurrent measurement of plankton production by this wide range of techniques. Further investigation of DOM excretion and light-enhanced respiration during diatom blooms is warranted

Observation of the B0 →ρ0ρ0 decay from an amplitude analysis of B0 → (π+π-) (π+π-) decays

Proton-proton collision data recorded in 2011 and 2012 by the LHCb experiment, corresponding to an integrated luminosity of 3.0 fb−1 , are analysed to search for the charmless B0 → ρ 0ρ 0 decay. More than 600 B0 → (π +π −)(π +π −) signal decays are selected and used to perform an amplitude analysis, under the assumption of no CP violation in the decay, from which the B0 → ρ 0ρ 0 decay is observed for the first time with 7.1 standard deviations significance. The fraction of B0 → ρ 0ρ 0 decays yielding a longitudinally polarised final state is measured to be fL = 0.745+0.048 −0.058(stat) ± 0.034(syst). The B0 → ρ 0ρ 0 branching fraction, using the B0 → φK∗ (892)0 decay as reference, is also reported as B(B0 → ρ 0ρ 0 ) = (0.94 ± 0.17(stat) ± 0.09(syst) ± 0.06(BF)) × 10−6

A measurement of the CP asymmetry difference between Λc + → pK − K + and pπ−π+ decays

The difference between the CP asymmetries in the decays Λ + c → pK−K+ and Λ + c → pπ−π + is presented. Proton-proton collision data taken at centre-of-mass energies of 7 and 8 TeV collected by the LHCb detector in 2011 and 2012 are used, corresponding to an integrated luminosity of 3 fb−1 . The Λ + c candidates are reconstructed as part of the Λ 0 b → Λ + c µ −X decay chain. In order to maximize the cancellation of production and detection asymmetries in the difference, the final-state kinematic distributions of the two samples are aligned by applying phase-space-dependent weights to the Λ + c → pπ−π + sample. This alters the definition of the integrated CP asymmetry to A wgt CP (pπ−π +). Both samples are corrected for reconstruction and selection efficiencies across the five-dimensional Λ + c decay phase space. The difference in CP asymmetries is found to be ∆A wgt CP = ACP (pK−K+) − A wgt CP (pπ−π +) = (0.30 ± 0.91 ± 0.61) %, where the first uncertainty is statistical and the second is systemati

Observation of a New Excited Ds+ Meson in B0 →d-D+K+π-Decays

Using pp collision data corresponding to an integrated luminosity of 5.4 fb−1 collected with the LHCb detector at a center-of-mass energy of 13 TeV, the B0 → D−DþKþπ− decay is studied. A new excited Dþ s meson is observed decaying into the DþKþπ− final state with large statistical significance. The pole mass and width, and the spin parity of the new state are measured with an amplitude analysis to be mR ¼ 2591 6 7 MeV, ΓR ¼ 89 16 12 MeV, and JP ¼ 0−, where the first uncertainty is statistical and the second systematic. Fit fractions for all components in the amplitude analysis are also reported. The new resonance, denoted as Ds0ð2590Þþ, is a strong candidate to be the Dsð21 S0Þþ state, the radial excitation of the pseudoscalar ground-state Dþ s meson