Contribution of resonance energy transfer to the luminescence quenching of upconversion nanoparticles with graphene oxide.

Upconversion nanoparticles (UCNP) are increasingly used due to their advantages over conventional fluorophores, and their use as resonance energy transfer (RET) donors has permitted their application as biosensors when they are combined with appropriate RET acceptors such as graphene oxide (GO). However, there is a lack of knowledge about the design and influence that GO composition produces over the quenching of these nanoparticles that in turn will define their performance as sensors. In this work, we have analysed the total quenching efficiency, as well as the actual values corresponding to the RET process between UCNPs and GO sheets with three different chemical compositions. Our findings indicate that excitation and emission absorption by GO sheets are the major contributor to the observed luminescence quenching in these systems. This challenges the general assumption that UCNPs luminescence deactivation by GO is caused by RET. Furthermore, RET efficiency has been theoretically calculated by means of a semiclassical model considering the different nonradiative energy transfer rates from each Er3+ ion to the GO thin film. These theoretical results highlight the relevance of the relative positions of the Er3+ ions inside the UCNP with respect to the GO sheet in order to explain the RET-induced efficiency measurements.

Femtosecond laser reshaping yields gold nanorods with ultranarrow surface plasmon resonances.

The irradiation of gold nanorod colloids with a femtosecond laser can be tuned to induce controlled nanorod reshaping, yielding colloids with exceptionally narrow localized surface plasmon resonance bands. The process relies on a regime characterized by a gentle multishot reduction of the aspect ratio, whereas the rod shape and volume are barely affected. Successful reshaping can only occur within a narrow window of the heat dissipation rate: Low cooling rates lead to drastic morphological changes, and fast cooling has nearly no effect. Hence, a delicate balance must be achieved between irradiation fluence and surface density of the surfactant on the nanorods. This perfection process is appealing because it provides a simple, fast, reproducible, and scalable route toward gold nanorods with an optical response of exceptional quality, near the theoretical limit.

Femtosecond Laser-Controlled Tip-to-Tip Assembly and Welding of Gold Nanorods.

Directed assembly of gold nanorods through the use of dithiolated molecular linkers is one of the most efficient methodologies for the morphologically controlled tip-to-tip assembly of this type of anisotropic nanocrystals. However, in a direct analogy to molecular polymerization synthesis, this process is characterized by difficulties in chain-growth control over nanoparticle oligomers. In particular, it is nearly impossible to favor the formation of one type of oligomer, making the methodology hard to use for actual applications in nanoplasmonics. We propose here a light-controlled synthetic procedure that allows obtaining selected plasmonic oligomers in high yield and with reaction times in the scale of minutes by irradiation with low fluence near-infrared (NIR) femtosecond laser pulses. Selective inhibition of the formation of gold nanorod n-mers (trimers) with a longitudinal localized surface plasmon in resonance with a 800 nm Ti:sapphire laser, allowed efficient trapping of the (n - 1)-mers (dimers) by hot spot mediated photothermal decomposition of the interparticle molecular linkers. Laser irradiation at higher energies produced near-field enhancement at the interparticle gaps, which is large enough to melt gold nanorod tips, offering a new pathway toward tip-to-tip welding of gold nanorod oligomers with a plasmonic response at the NIR. Thorough optical and electron microscopy characterization indicates that plasmonic oligomers can be selectively trapped and welded, which has been analyzed in terms of a model that predicts with reasonable accuracy the relative concentrations of the main plasmonic species.

Coordinación y enfoque multidisciplinar de un caso complejo / Coordination and multidisciplinary approach to a complex case

Este artículo clínico describe el proceso de resolución exitosa de un problema estético y funcional por ausencia y malposición de dientes y pérdida de soporte periodontal de una paciente de 41 años, discutiendo algunos objetivos o decisiones claves del proceso. Se analizan paso a paso las cuatro fases del tratamiento multidisciplinar hasta conseguir los objetivos clínicos propuestos: 1) mantener la estabilidad de los tejidos periodontales y periimplantarios; 2) recuperar la arquitectura periodontal; 3) recuperar la función masticatoria; 4) obtener un resultado estético aceptable; 5) conseguir la satisfacción estética y funcional de la paciente. El artículo postula que la visión integrada de la ciencia y práctica odontológica y una adecuada coordinación de los profesionales es lo que permitió llevar a cabo con éxito un trabajo complejo de más de dos años de duración sin solapamienos, interferencias o lagunas (AU)

This clinical article describes the successful treatment of an aesthetic and functional problem caused by the bad positioning and/or absence of teeth plus the loss of dental support in a 41 year old female patient. The article includes the discussion of various objectives and important decisions taken during the process. The four phases of multidisciplinary treatment are analysed step by step (periodontics, orthodontics, prosthodontics), until the following clinical objectives are achieved: 1) conservation of the stability of the periodontal and implant tissues; 2) restoration of the periodontal architecture; 3) restoration of the masticatory function; 4) achievement of a satisfactory aesthetic result; 5) the patient's satisfaction both in the aesthetic and functional aspect. This article claims that the integral scientific vision combined with practical dentistry and adequate professional coordination resulted in the successful completion of a complicated project that lasted over two years and was carried out with no overlaps, interferences or delays (AU)

Tratamientos pluridisciplinarios, filosofía de trabajo, comunicación, reciprocidad ética / Multidisciplinary treatments, working philosophy, communication, ethical commitment

El presente trabajo tiene como objetivo mostrar la resolución de un problema osteoparticular, debido a la falta de remodelación condilar, asociado a enfermedad periodontal. Tras las exploraciones dental, periodontal, radiológica y articular se propuso a la paciente un plan de tratamiento para estabilizar la destrucción periodontal y la posición condilar. La buena comunicación con la paciente, antes y durante el tratamiento, permitió llevar a cabo satisfactoriamente todas. Las fases, incluida la de mantenimiento consiguiendo remisión de la sintomatología y estabilidad tanto condilar y oclusal como periodontal (AU)