Inkjet printing of functional materials for optical and photonic applications

Inkjet printing, traditionally used in graphics, has been widely investigated as a valuable tool in the preparation of functional surfaces and devices. This review focuses on the use of inkjet printing technology for the manufacturing of different optical elements and photonic devices. The presented overview mainly surveys work done in the fabrication of micro-optical components such as microlenses, waveguides and integrated lasers; the manufacturing of large area light emitting diodes displays, liquid crystal displays and solar cells; as well as the preparation of liquid crystal and colloidal crystal based photonic devices working as lasers or optical sensors. Special emphasis is placed on reviewing the materials employed as well as in the relevance of inkjet in the manufacturing of the different devices showing in each of the revised technologies, main achievements, applications and challenges

Anisotropic light emissions in luminescent solar concentrators-isotropic systems

In this paper we develop a model to describe the emission profile from randomly oriented dichroic dye molecules in a luminescent solar concentrator (LSC) waveguide as a function of incoming light direction. The resulting emission is non-isotropic, in contradiction to what is used in almost all previous simulations on the performance of LSCs, and helps explain the large surface losses measured in these devices. To achieve more precise LSC performance simulations we suggest that the dichroic nature of the dyes must be included in the future modeling efforts

Nano-second laser interference photoembossed microstructures for enhanced cell alignment

Photoembossing is a powerful photolithographic technique to prepare surface relief structures relying on polymerization-induced diffusion in a solventless development step. Conveniently, surface patterns are formed by two or more interfering laser beams without the need for a lithographic mask. The use of nanosecond pulsed light-based interference lithography strengthens the pattern resolution through the absence of vibrational line pattern distortions. Typically, a conventional photoembossing protocol consists of an exposure step at room temperature that is followed by a thermal development step at high temperature. In this work, we explore the possibility to perform the pulsed holographic exposure directly at the development temperature. The surface relief structures generated using this modified photoembossing protocol are compared with those generated using the conventional one. Importantly, the enhancement of surface relief height has been observed by exposing the samples directly at the development temperature, reaching approximately double relief heights when compared to samples obtained using the conventional protocol. Advantageously, the light dose needed to reach the optimum height and the amount of photoinitiator can be substantially reduced in this modified protocol, demonstrating it to be a more efficient process for surface relief generation in photopolymers. Kidney epithelial cell alignment studies on substrates with relief-height optimized structures generated using the two described protocols demonstrate improved cell alignment in samples generated with exposure directly at the development temperature, highlighting the relevance of the height enhancement reached by this method. Although cell alignment is well-known to be enhanced by increasing the relief height of the polymeric grating, our work demonstrates nano-second laser interference photoembossing as a powerful tool to easily prepare polymeric gratings with tunable topography in the range of interest for fundamental cell alignment studies

Gram-negative prosthetic joint infection: outcome of a debridement, antibiotics and implant retention approach. A large multicentre study

AbstractWe aim to evaluate the epidemiology and outcome of gram-negative prosthetic joint infection (GN-PJI) treated with debridement, antibiotics and implant retention (DAIR), identify factors predictive of failure, and determine the impact of ciprofloxacin use on prognosis. We performed a retrospective, multicentre, observational study of GN-PJI diagnosed from 2003 through to 2010 in 16 Spanish hospitals. We define failure as persistence or reappearance of the inflammatory joint signs during follow-up, leading to unplanned surgery or repeat debridement >30 days from the index surgery related death, or suppressive antimicrobial therapy. Parameters predicting failure were analysed with a Cox regression model. A total of 242 patients (33% men; median age 76 years, interquartile range (IQR) 68–81) with 242 episodes of GN-PJI were studied. The implants included 150 (62%) hip, 85 (35%) knee, five (2%) shoulder and two (1%) elbow prostheses. There were 189 (78%) acute infections. Causative microorganisms were Enterobacteriaceae in 78%, Pseudomonas spp. in 20%, and other gram-negative bacilli in 2%. Overall, 19% of isolates were ciprofloxacin resistant. DAIR was used in 174 (72%) cases, with an overall success rate of 68%, which increased to 79% after a median of 25 months' follow-up in ciprofloxacin-susceptible GN-PJIs treated with ciprofloxacin. Ciprofloxacin treatment exhibited an independent protective effect (adjusted hazard ratio (aHR) 0.23; 95% CI, 0.13–0.40; p <0.001), whereas chronic renal impairment predicted failure (aHR, 2.56; 95% CI, 1.14–5.77; p 0.0232). Our results confirm a 79% success rate in ciprofloxacin-susceptible GN-PJI treated with debridement, ciprofloxacin and implant retention. New therapeutic strategies are needed for ciprofloxacin-resistant PJI

Mechanical frustration and spontaneous polygonal folding in active nematic sheets

et al.We analyze the bending response to light or heat of a solid nematic disk with a director twisted from being radial on the upper surface to be azimuthal on the lower. We find a number of curl lobes determined purely by the geometry of the mechanical frustration that arises during the response. © 2012 American Physical Society.M.W. thanks the EPSRC for funding (Grant No. EP/E051251/1), and C.S.S. thanks the Spanish MINECO project MAT2011-27978-C02-02, CSIC project i-LINK0394, Gobierno de Aragón, and FEDER (EU).Peer Reviewe

Influence of blue and red light illumination on the holographic storage in an azopolyester–PMMA blend

Volume holographic polarization gratings have been stored in thick films of blends of a side-chain azobenzene polyester and a poly(methyl methacrylate) (PMMA) homopolymers. The azobenzene content in the blend is 0.2 wt%, and the holograms are recorded by using 2 ms 4 mJ/cm2 488 nm light pulses. The dependence of holographic storage on the recording condition has been studied. No stable gratings can be recorded in thermally quenched films. The presence of cis isomers that can be induced by blue light irradiation seems to be necessary to store stable gratings. The cis isomer content and consequently the grating efficiency can be changed by blue and red light irradiation. By choosing appropriate conditions stable and rewritable polarization gratings have been recorded. Up to 20 gratings with diffraction efficiency values higher than 5 × 10-5 have been multiplexed. © 2013 Elsevier B.V. All rights reserved.This work was supported by the Spanish MINECO Project MAT2011-27978-C02-02, Gobierno de Aragón and FEDER funding (EU). I.D. acknowledges funding from CSIC and from Fondo Social Europeo (FSE) through a JAE-Doc Grant.Peer Reviewe

Anisotropic light emissions in luminescent solar concentrators-isotropic systems

In this paper we develop a model to describe the emission profile from randomly oriented dichroic dye molecules in a luminescent solar concentrator (LSC) waveguide as a function of incoming light direction. The resulting emission is non-isotropic, in contradiction to what is used in almost all previous simulations on the performance of LSCs, and helps explain the large surface losses measured in these devices. To achieve more precise LSC performance simulations we suggest that the dichroic nature of the dyes must be included in the future modeling efforts. © 2013 Optical Society of America.M.D. would like to acknowledge the support of STW Vidi grant 7940 and C.S.S. thanks the Spanish MINECO project MAT2011-27978-C02-02, CSIC project i-LINK0394, Gobierno de Aragón, and FEDER (EU).Peer Reviewe

Angular deficits in flat space: Remotely controllable apertures in nematic solid sheets

Recent attention has been given to the realization of angular deficits and surpluses in the local ground-state geometry of thin sheets of nematic solids as out-of-plane deformations. Such systems exhibit conical or anti-conical curvature sites, or possibly arrays of such polyhedral corners, in order to satisfy the material's spontaneous strain-generated metric requirements. Here, we turn the angular deficit requirement on its head, and show theoretically and experimentally that by appropriately altering the topology of the initially flat sheet-for example, by cutting it in carefully chosen regions-the same angular deficits and surpluses may manifest simply in-plane by changing the geometry of the cut region. Such amechanism offers a route to apertures or arrays of apertures that may be reversibly opened and closed by applying spontaneous strain with heat, light or chemical potential. Copyright © The Royal Society 2013.M.W. thanks the EPSRC for funding under grant no. EP/E051251/1, and C.S.S. thanks the Spanish MINECO project MAT2011-27978-C02-02, CSIC project i-LINK0394, Gobierno de Aragón, and FEDER funding (EU) for their financial support.Peer Reviewe

Bases para el control de la salmonelosis en las explotaciones porcinas

PublishedPublicación especial de la Información Técnica nº 231 del Departamento de Agricultura, Ganadería y Medio Ambiente del Gobierno de Aragón (2011) como homenaje a Cristóbal Montañé