Probing gigahertz coherent acoustic phonons in TiO2 mesoporous thin films.

Ultrahigh-frequency acoustic-phonon resonators usually require atomically flat interfaces to avoid phonon scattering and dephasing, leading to expensive fabrication processes, such as molecular beam epitaxy. Mesoporous thin films are based on inexpensive wet chemical fabrication techniques that lead to relatively flat interfaces regardless the presence of nanopores. Here, we report mesoporous titanium dioxide-based acoustic resonators with resonances up to 90 GHz, and quality factors from 3 to 7. Numerical simulations show a good agreement with the picosecond ultrasonics experiments. We also numerically study the effect of changes in the speed of sound on the performance of the resonator. This change could be induced by liquid infiltration into the mesopores. Our findings constitute the first step towards the engineering of building blocks based on mesoporous thin films for reconfigurable optoacoustic sensors.

[Long-term effects of a mindfulness and self-compassion program with Primary Healthcare professionals]. / Persistencia a largo plazo de los efectos de un programa de mindfulness y autocompasión en profesionales sanitarios de Atención Primaria.

BACKGROUND: The effectiveness of mindfulness and self-compassion-based interventions (MSCI) on emotional fatigue and stress in Primary Healthcare (PHC) professionals has been demonstrated in the short term. The aims of this work were to assess whether these effects persist after two years, and if the observed results differ between those who practiced mindfulness regularly during the follow-up (meditators) and those who did not. METHODS: Prospective study - pre-post and two years after performing an MSCI that was offered to all PHC professionals in Navarra, with group sessions of 2.5 hours / week for 8 weeks. Attending at least 75% of the sessions and practicing at home for 45 minutes a day were mandatory. At the three moments of the study, questionnaires were distributed to measure levels of mindfulness (FFMQ), self-compassion (SCS), perceived stress (PSQ) and burnout (MBI). At the end of the follow-up period, participants were asked if they were meditators and the time they dedicated to this weekly. RESULTS: Forty-eight professionals were enrolled and 41 (83% women) met the inclusion criteria, without loss to follow-up. Mean scores in mindfulness, self-compassion and perceived stress significantly improved after the intervention and in the long term (p <0.001), without observing differences in the level of burnout. The group of meditators achieved a greater long-term improvement in self-compassion (3.6 points vs. 1.6). CONCLUSIONS: The effectiveness of an MSCI persists two years later regardless of meditator status, although there is a significant improvement in self-compassion in the meditators.

Exploring physical and chemical properties in new multifunctional indium-, bismuth-, and zinc-based 1D and 2D coordination polymers.

Main group element coordination polymers (MGE-CPs) are important compounds for the development of multifunctional materials. However, there has been a shortage of studies regarding their structural, optical, catalytic, mechanical, and antibacterial properties. This work presents an exhaustive study of a set of crystalline MGE-CPs obtained from bismuth and indium metals and iminodiacetate, 1,2,4,5-benzenetetracarboxylate, and 2,2'-bipyridine as building blocks. An in-depth topological analysis of the networks was carried out. Additionally, nanoindentation studies were performed on two representative low-dimensional compounds in order to find the relationships between their structural features and their intrinsic mechanical properties (hardness and elasticity). The solid-state photoluminescence (SSPL) properties were also studied in terms of excitation, emission, lifetimes values, and CIE chromaticites. Moreover, the heterogeneous catalytic activities of the compounds were evaluated with the cyanosilylation reaction using a set of carbonylic substrates under solvent-free conditions. Finally, the inhibitory effect of the Bi-CPs on the growth of microorganisms such as Escherichia coli, Salmonella enterica serovar Typhimurium, and Pseudomonas aeruginosa, which are associated with relevant infectious diseases, is reported.

Controlled deposition of silver nanoparticles in mesoporous single- or multilayer thin films: from tuned pore filling to selective spatial location of nanometric objects.

Silver nanoparticle assemblies are embedded within mesoporous oxide thin films by an in situ mild reduction leading to nanoparticle-mesoporous oxide thin-film composites (NP@MOTF). A quantitative method based on X-ray reflectivity is developed and validated with energy dispersive spectroscopy in order to assess pore filling. The use of dilute formaldehyde solutions leads to control over the formation of silver nanoparticles within mesoporous titania films. Inclusion of silver nanoparticles in mesoporous silica requires more drastic conditions. This difference in reactivity can be exploited to selectively synthesize nanoparticles in a predetermined layer of a multilayered mesoporous stack leading to complex 1D-ordered multilayers with precise spatial location of nanometric objects. The metal oxide nanocomposites synthesized have potential applications in catalysis, optical devices, surface-enhanced Raman scattering, and metal enhancement fluorescence.