Prediction of Degraded Infrastructure Conditions for Railway Operation.

In the railway sector, rolling stock and infrastructure must be maintained in perfect condition to ensure reliable and safe operation for passengers. Climate change is affecting the urban and regional infrastructure through sea level rise, water accumulations, river flooding, and other increased-frequency extreme natural situations (heavy rains or snows) which pose a challenge to maintenance. In this paper, the use of artificial intelligence based on predictive maintenance implementation is proposed for the early detection of degraded conditions of a bridge due to extreme climatic conditions. For this prediction, continuous monitoring is proposed, with the aim of establishing alarm thresholds to detect dangerous situations, so restrictions could be determined to mitigate the risk. However, one of the main challenges for railway infrastructure managers nowadays is the high cost of monitoring large infrastructures. In this work, a methodology for monitoring railway infrastructures to define the optimal number of transductors that are economically viable and the thresholds according to which infrastructure managers can make decisions concerning traffic safety is proposed. The methodology consists of three phases that use the application of machine learning (Random Forest) and artificial cognitive systems (LSTM recurrent neural networks).

Cost-effective screen printing approach for Ce/Nd-doped ZnAl2O4 films: tuning crystallinity induced by the substrate.

Near-infrared (NIR) emitting phosphors are currently receiving considerable attention owing to their high demand in various applications, such as light detection and ranging (LiDAR), short-range communications, security, biosensing and night vision lighting applications. The miniaturization of photonic components demands the integration of thin films into exploitable devices. In this context, NIR emitting ZnAl2O4:Ce/Nd films of hundreds of nanometer thickness are synthesized using a scalable and cost-efficient approach to screen printing. Cerium co-doping is responsible for the Nd emission in the NIR through energy transfer by exciting the films under UV excitation at around 360 nm. Through the proper design of ink, dense Nd/Ce doped ZnAl2O4 ceramic films were produced using polycrystalline alumina. The use of polycrystalline alumina substrates opens up new opportunities because this ceramic is a cheap and well-known substrate for optoelectronic packaging. During manufacturing, as a direct effect of predominant crystal growth over the polycrystalline alumina substrate, an increase in emission intensity is achieved. The results obtained by X-ray photoelectron (XPS) and X-ray absorption near edge spectroscopy (XANES) serve to determine the oxidation state of Ce. The findings of this study indicate that a higher concentration of Ce4+ promotes NIR emission. This study may contribute to a better understanding of film production processes of films based on the ZnAl2O4 matrix and guide future studies on films for NIR emitters.

CNTs/Fe-BTC Composite Materials for the CO2-Photocatalytic Reduction to Clean Fuels: Batch and Continuous System.

CNTs/Fe-BTC composite materials were synthesized with the one-step solvothermal method. MWCNTs and SWCNTs were incorporated in situ during synthesis. The composite materials were characterized by different analytical techniques and used in the CO2-photocatalytic reduction to value-added products and clean fuels. In the incorporation of CNTs into Fe-BTC, better physical-chemical and optical properties were observed compared to Fe-BTC pristine. SEM images showed that CNTs were incorporated into the porous structure of Fe-BTC, indicating the synergy between them. Fe-BTC pristine showed to be selective to ethanol and methanol; although, it was more selective to ethanol. However, the incorporation of small amounts of CNTs into Fe-BTC not only showed higher production rates but changes in the selectivity compared with the Fe-BTC pristine were also observed. It is important to mention that the incorporation of CNTs into MOF Fe-BTC allowed for increasing the mobility of electrons, decreasing the recombination of charge carriers (electron/hole), and increasing the photocatalytic activity. In both reaction systems (batch and continuous), composite materials showed to be selective towards methanol and ethanol; however, in the continuous system, lower production rates were observed due to the decrease in the residence time compared to the batch system. Therefore, these composite materials are very promising systems to convert CO2 to clean fuels that could replace fossil fuels soon.

Deep-Ultraviolet Emitter: Rare-Earth-Free ZnAl2O4 Nanofibers via a Simple Wet Chemical Route.

Deep-UV (180-280 nm) phosphors have attracted tremendous interest in tri-band-based white light-emitting diode (LED) technology, bio- and photochemistry, as well as various medical fields. However, the application of many UV-emitting materials has been hindered due to their poor thermal or chemical stability, complex synthesis, and environmental harmfulness. A particular concern is posed by the utilization of rare earths affected by rising price and depletion of natural resources. As a consequence, the development of phosphors without rare-earth elements represents an important challenge. In this work, as a potential UV-C phosphor, undoped ZnAl2O4 fibers have been synthesized by a cost-efficient wet chemical route. The rare-earth-free ZnAl2O4 nanofibers exhibit a strong UV emission with two bands peaking at 5.4 eV (230 nm) and 4.75 eV (261 nm). The emission intensity can be controlled by tuning the Zn/Al ratio. A structure-property relationship has been thoroughly studied to understand the origin of the UV emission. For this reason, ZnAl2O4 nanofibers have been analyzed by X-ray absorption near-edge structure (XANES), extended X-ray absorption fine structure (EXAFS), X-ray diffraction (XRD), and Raman spectroscopy techniques showing that a normal spinel structure of the synthesized material is preserved within a wide range of Zn/Al ratios. The experimental evidence of a strong and narrow band at 7.04 eV in the excitation spectrum of the 5.4 eV emission suggests its excitonic nature. Moreover, the 4.75 eV emission is shown to be related to excitons perturbed by lattice defects, presumably oxygen or cation vacancies. These findings shed light on the design of UV-C emission devices for sterilization based on a rare-earth-free phosphor, providing a feasible alternative to the conventional phosphors doped with rare-earth elements.

Photocatalytic Degradation of Dyes Using Titania Nanoparticles Supported in Metal-Organic Materials Based on Iron.

Composite materials based on titania nanoparticles (TiO2 NPs) and three metal-organic frameworks (MOFs) called MIL-53 (Fe) ((Fe (III) (OH) (1,4-BDC)), MILs (Materials Institute Lavoisier)), MIL-100 (Fe) (Fe3O(H2O)2OH(BTC)2), and Fe-BTC (iron-benzenetricarboxylate) with different percentages of TiO2 NPs (0.5, 1, and 2.5% wt.) were synthesized using the solvothermal method and used as photocatalytic materials in the degradation of two dyes (Orange II and Reactive Black 5 (RB5)). The pristine and composite materials were characterized with X-ray diffraction, Raman, UV-Vis and Fourier transform infrared spectroscopy and scanning electron microscopy techniques. The 2.5TiO2/MIL-100 composite material showed the best results for the degradation of both dyes (Reactive Black 5 and Orange II dye, 99% and 99.5% degradation in 105 and 150 min, respectively). The incorporation of TiO2 NPs into MOFs can decrease the recombination of the change carrier in the MOF, increasing the photocatalytic activity of a pristine MOF. Results therefore indicated that the synthesized MOF nanocomposites have good potential for wastewater treatment.

Validation of an Affordable Handheld Wavefront Autorefractor.

SIGNIFICANCE: There is a critical need for tools that increase the accessibility of eye care to address the most common cause of vision impairment: uncorrected refractive errors. This work assesses the performance of an affordable autorefractor, which could help reduce the burden of this health care problem in low-resource communities. PURPOSE: The purpose of this study was to validate the commercial version of a portable wavefront autorefractor for measuring refractive errors. METHODS: Refraction was performed without cycloplegia using (1) a standard clinical procedure consisting of an objective measurement with a desktop autorefractor followed by subjective refraction (SR) and (2) with the handheld autorefractor. Agreement between both methods was evaluated using Bland-Altman analysis and by comparing the visual acuity (VA) with trial frames set to the resulting measurements. RESULTS: The study was conducted on 54 patients (33.9 ± 14.1 years of age) with a spherical equivalent (M) refraction determined by SR ranging from -7.25 to 4.25 D (mean ± SD, -0.93 ± 1.95 D). Mean differences between the portable autorefractor and SR were 0.09 ± 0.39, -0.06 ± 0.13, and 0.02 ± 0.12 D for M, J0, and J45, respectively. The device agreed within 0.5 D of SR in 87% of the eyes for spherical equivalent power. The average VAs achieved from trial lenses set to the wavefront autorefractor and SR results were 0.02 ± 0.015 and 0.015 ± 0.042 logMAR units, respectively. Visual acuity resulting from correction based on the device was the same as or better than that achieved by SR in 87% of the eyes. CONCLUSIONS: This study found excellent agreement between the measurements obtained with the portable autorefractor and the prescriptions based on SR and only small differences between the VA achieved by either method.

DOME-SHAPED MACULA IN MYOPIC EYES: Twelve-Month Follow-up.

PURPOSE: To study the long-term clinical course of dome-shaped macula in myopic eyes and to evaluate treatment efficacy for subretinal fluid (SRF) as a related complication. METHODS: A retrospective, single-center consecutive case series study was conducted. The authors analyzed myopic eyes with dome-shaped macula in patients who presented for evaluation of decreased vision. Dome-shaped macula was defined as a convexity of the retina-choroidal macular complex seen on spectral domain optical coherence tomography images. All patients were followed for at least 12 months (mean, 25 months). Fluorescein angiography and/or indocyanine green angiography were performed in cases with SRF to rule out choroidal neovascularization. RESULTS: A total of 56 dome-shaped macula eyes from 36 patients were included in the study (bilateral in 55% of patients). Mean patient age was 56.9 ± 13.1 years. The mean spherical equivalent was -9.1 ± 6.0 diopters; 53% of eyes were considered highly myopic (>-6 diopters) and 47% of eyes were mildly myopic. In most cases (37 eyes; 66.1%), the dome-shaped macula was detected on vertical spectral domain optical coherence tomography scan patterns. No significant changes (P ≥ 0.1) were observed in mean best-corrected visual acuity or mean central foveal thickness from baseline to final follow-up. Subretinal fluid was present in 29 eyes (51.8%) at baseline, with no differences in best-corrected visual acuity in eyes with and without SRF (P ≥ 0.05). Nineteen of the 29 SRF eyes were treated: 8 underwent low-fluence photodynamic therapy, whereas 7 received bevacizumab, and 4 ranibizumab. No significant differences were found between treated and untreated SRF eyes in best-corrected visual acuity improvement (P ≥ 0.1), or complete resolution of SRF (P ≥ 0.1). Likewise, photodynamic therapy did not yield any significant benefit versus untreated eyes in best-corrected visual acuity or improvement of SRF. CONCLUSION: Dome-shaped macula is a condition associated with myopic eyes that seems to remain stable over time in terms of vision and macular profiles. It is often associated with chronic SRF, for which no effective treatment is current available. However, SRF does not seem to be a significant cause of visual impairment.

INCIDENCE AND RELATION WITH ANATOMICAL AND FUNCTIONAL VARIABLES OF POSTOPERATIVE MACULAR DISPLACEMENT IN RHEGMATOGENOUS RETINAL DETACHMENT.

PURPOSE: To investigate the incidence of postsurgical retinal displacement in patients treated with pars plana vitrectomy for rhegmatogenous retinal detachment and to assess the influence of displacement on macular function. METHODS: Observational prospective study of 20 consecutive cases of rhegmatogenous retinal detachment who underwent 23-G pars plana vitrectomy with gas (C3F8 or SF6) tamponade, and prone resting. Three months after surgery, retinal displacement was evaluated by fundus autofluorescence. Macular function was evaluated with optical coherence tomography, multifocal electroretinogram, best-corrected visual acuity, and stereopsis. RESULTS: Postoperative retinal displacement was observed in 60% of cases. No correlation between the type of tamponade used and retinal displacement was observed. Similarly, no association between retinal displacement and postoperative stereopsis or visual acuity was found. A lower amplitude in P1 wave on the multifocal electroretinogram was observed in eyes with rhegmatogenous retinal detachment compared with the contralateral eye. However, no statistically significant differences between groups with or without retinal displacement were found. CONCLUSION: Retinal displacement in patients who undergo pars plana vitrectomy to treat rhegmatogenous retinal detachment is common. However, this displacement does not seem to affect macular function.

Original Synthetic Route To Obtain a SrAl2O4 Phosphor by the Molten Salt Method: Insights into the Reaction Mechanism and Enhancement of the Persistent Luminescence.

SrAl2O4:Eu(2+), Dy(3+) has been extensively studied for industrial applications in the luminescent materials field, because of its excellent persistent luminescence properties and chemical stability. Traditionally, this strontium aluminate material is synthesized in bulk form and/or fine powder by the classic solid-state method. Here, we report an original synthetic route, a molten salt assisted process, to obtain highly crystalline SrAl2O4 powder with nanometer-scale crystals. The main advantages of salt addition are the increase of the reaction rate and the significant reduction of the synthesis temperature because of much higher mobility of reactants in the liquid medium than in the solid-state method. In particular, the formation mechanism of SrAl2O4, the role of the salt, and the phase's evolution have been explored as a function of temperature and time. Phosphorescent powders based on SrAl2O4:Eu(2+), Dy(3+) with high crystallinity are obtained after 1 h treatment at 900 °C. This work could promote further interest in adopting the molten salt strategy to process high-crystallinity materials with enhanced luminescence to design technologically relevant phosphors.

Autofluorescence and axial length as prognostic factors for outcomes of macular hole retinal detachment surgery in high myopia.

PURPOSE: To evaluate the results of fundus autofluorescence and axial length as prognostic factors for surgical outcome of macular hole retinal detachment in high myopic patients. METHODS: This is a retrospective, interventional, nonrandomized study. Patients were treated with posterior vitrectomy, internal limiting membrane peeling, and silicone oil tamponade. Best-corrected visual acuity, axial length, fundus autofluorescence, and spectral domain optical coherence tomography images were obtained. RESULTS: Fifteen eyes from 15 patients (mean age, 69.4 years) were evaluated. The mean refractive error was -19 diopters, and the mean axial length was 29.9 mm. The mean best-corrected visual acuity (logMAR) improved from 2.17 to 1.42 (P = 0.02) after a mean follow-up of 19.3 months. Spectral domain optical coherence tomography scans showed retinal detachment resolution in 13 eyes (86.6%) and macular hole closure in 9 eyes (60%). Fundus autofluorescence showed macular hypoautofluorescence with foveal involvement (mean area of 9.7 mm2) in 10 eyes (66.6%). Postoperative best-corrected visual acuity was significantly worse in these eyes (P = 0.009). Axial length >30 mm was found in the 2 cases with recurrent retinal detachment and in 4 of the 6 cases without macular hole closure (66.6%). CONCLUSION: Macular hole retinal detachment in high myopic patients can be successfully treated with vitrectomy, internal limiting membrane peeling, and silicone oil. Axial length >30 mm and macular hypoautofluorescence with foveal involvement seem to be prognostic factors for a worse anatomical and visual outcome.

INTRAVITREAL DEXAMETHASONE IMPLANT FOR RADIATION MACULOPATHY SECONDARY TO PLAQUE BRACHYTHERAPY IN CHOROIDAL MELANOMA.

PURPOSE: To evaluate the efficacy of intravitreal dexamethasone implant 0.7 mg (Ozurdex) in radiation maculopathy secondary to plaque brachytherapy in choroidal melanoma. METHODS: Twelve eyes diagnosed of radiation maculopathy secondary to plaque brachytherapy and treated with intravitreal dexamethasone implant were included. Visual acuity, foveal thickness using spectral domain optical coherence tomography, and grade of macular edema, using Horgan classification, were evaluated. RESULTS: Mean age was 65.5 ± 28 years (range, 40-82 years). Mean follow-up was 8.2 ± 7.8 months (range, 2-28 months). Mean visual acuity before treatment was, in logarithm of the minimum angle of resolution scale, 1 ± 0.58 (range, 0.4-2) and mean final visual acuity 0.8 ± 0.58 (range, 0.2-2), showing a nonsignificant trend to improvement (P = 0.091; Wilcoxon's test). Foveal thickness before treatment was 416 ± 263 µm (range, 222-725 µm) and final foveal thickness 254 ± 170 µm (range, 145-750), showing a significant decrease (P = 0.016; Wilcoxon's test). Referring to Horgan classification, a significant reduction in grades before and after treatment was demonstrated (P = 0.007; Wilcoxon's test). CONCLUSION: Ozurdex is a useful treatment for radiation maculopathy associated to plaque brachytherapy for uveal melanoma, with a significant decrease in foveal thickness and a significant improvement in Horgan classification. This anatomical improvement was correlated with a moderate improvement in visual acuity.

Uncommon Complication Post-deep Sclerectomy: Giant Retinal Tear.

Glaucoma is a prevalent neurodegenerative disease. It causes progressive visual loss and is one of the most common causes of blindness worldwide. It can be categorized into open-angle or closed-angle glaucoma. Primary congenital glaucoma (PCG) is a subdivision of open-angle glaucoma. Non-penetrating deep sclerectomy (NPDS) is a surgical method for managing open-angle and primary congenital glaucoma, which was first introduced in 1990. During NPDS, a sclera flap is raised but not completely removed, and the outer part of Schlemm's canal and trabecular meshwork, along with the juxtacanalicular tissue, are excised without completely penetrating the eye. Therefore, it is considered a safe and efficient option for controlling intraocular pressure. This report shows a unique case of uncommon complication post-deep sclerectomy, a giant retinal tear, after undergoing non-penetrating deep sclerectomy for primary congenital glaucoma.

Reversible optical control of magnetism in engineered artificial multiferroics.

Optical means instead of electric fields may offer a new pathway for low-power and wireless control of magnetism, holding great potential to design next-generation memory and spintronic devices. Artificial multiferroic materials have shown remarkable suitability as platforms towards the optical control of magnetic properties. However, the practical use of magnetic modulation should be both stable and reversible and, particularly, it should occur at room temperature. Here we show an unprecedented reversible modulation of magnetism using low-intensity visible-light in Fe75Al25/BaTiO3 heterostructures, at room temperature. This is enabled by the existence of highly oriented charged domain walls arranged in arrays of alternating in-plane and out-of-plane ferroelectric domains with stripe morphology. Light actuation yields a net anisotropic stress caused by ferroelectric domain switching, which leads to a 90-degree reorientation of the magnetic easy axis. Significant changes in the coercivity and squareness ratio of the hysteresis loops can be light-modulated, encouraging the development of novel low energy-consumption wireless magneto-optical devices.

Concomitant Light-Reversible Magnetic Response in Multiferroic Oxide Heterostructures for Multiphysics Applications.

The concept of multiphysics, where materials respond to diverse external stimuli, such as magnetic fields, electric fields, light irradiation, stress, heat, and chemical reactions, plays a fundamental role in the development of innovative devices. Nanomanufacturing, especially in low-dimensional systems, enhances the synergistic interactions taking place on the nanoscale. Light-matter interaction, rather than electric fields, holds great promise for achieving low-power, wireless control over magnetism, solving two major technological problems: the feasibility of electrical contacts at smaller scales and the undesired heating of the devices. Here, we shed light on the remarkable reversible modulation of magnetism using visible light in epitaxial Fe3O4/BaTiO3 heterostructure. This achievement is underpinned by the convergence of two distinct mechanisms. First, the magnetoelastic effect, triggered by ferroelectric domain switching, induces a proportional change in coercivity and remanence upon laser illumination. Second, light-matter interaction induces charged ferroelectric domain walls' electrostatic decompensations, acting intimately on the magnetization of the epitaxial Fe3O4 film by magnetoelectric coupling. Crucially, our experimental results vividly illustrate the capability to manipulate magnetic properties using visible light. This concomitant mechanism provides a promising avenue for low-intensity visible-light manipulation of magnetism, offering potential applications in multiferroic devices.

Correction: Assesment of the QuickSee wavefront autorefractor for characterizing refractive errors in school-age children.

[This corrects the article DOI: 10.1371/journal.pone.0240933.].

One-year results of a flexible regimen with ranibizumab therapy in macular degeneration: relationship with the number of injections.

PURPOSE: To evaluate the efficacy and safety of a flexible regimen with intravitreal injections of ranibizumab in patients with naive choroidal neovascularization secondary to age-related macular degeneration and to determine whether the final outcome is related to the number of injections. METHODS: Prospective, noncomparative, consecutive case series study. We included 90 eyes of 88 patients that were initially treated with 3 consecutive monthly intravitreal injections of ranibizumab, and thereafter, follow-up visits were progressively spread out to a maximum of 8 weeks apart in the absence of visual acuity loss and signs of lesion activity. The primary end points were changes in visual acuity (Early Treatment Diabetic Retinopathy Study letters), foveal thickness measured by spectral-domain optical coherence tomography, and lesion size (LS) measured by fluorescein angiography. RESULTS: The median visual acuity improved from 53 letters at baseline to 60 letters at Month 1 (P < 0.0001), 63 letters at Month 3 (P < 0.0001), and 60 letters at Month 12 (P < 0.0001). A significant reduction was also observed in foveal thickness and LS (P < 0.0001). The mean number of injections was 4.4, and the mean number of visits was 8.0. Treatment consisted of 3 injections for 40% of patients, and 60% of patients received more than 3 injections. No significant association was observed between the visual acuity improvement and the number of injections. No relevant side effects were observed. CONCLUSION: A flexible regimen with ranibizumab therapy is efficacious and safe in patients with neovascular age-related macular degeneration, reducing both the burden of injections and follow-up visits. The visual acuity improvement was independent of the number of injections.

Intravitreal ranibizumab for choroidal neovascularization secondary to pathological myopia: 12-month follow-up.

PURPOSE: To evaluate the efficacy and safety of intravitreal ranibizumab in the treatment of choroidal neovascularization (CNV) due to pathological myopia (PM). METHODS: This retrospective case series studied outcomes in patients with CNV secondary to PM who were treated with intravitreal ranibizumab. Patients underwent complete ophthalmic evaluation, which included best-corrected visual acuity testing measured with Early Treatment Diabetic Retinopathy Study charts, optical coherence tomography (OCT) and baseline fluorescein angiography (FA). Indications for retreatment included the persistence of subretinal fluid on OCT as well as hemorrhages and new CNV on FA. Patients were followed for a minimum of 12 months. RESULTS: We treated 29 eyes in 29 patients; the mean age was 56.8 years. Thirteen eyes were naïve, while 16 had been previously treated with photodynamic therapy or intravitreal bevacizumab. The mean initial visual acuity was 44.8 letters; at the 12-month follow-up, it was 53.7 letters. The mean OCT foveal thickness decreased by 35.3 µm. Patients received an average of 1.38 injections. Statistically significant differences were observed both in visual acuity and in central foveal thickness. All subgroups had favorable outcomes. None of the patients developed injection-induced complications or drug-related side effects. CONCLUSION: Intravitreal injection of ranibizumab appears to be safe and efficacious in patients with CNV secondary to PM followed over a 12-month period.

Effect of the Na2O-Nb2O5-P2O5 glass additive on the structure, dielectric and energy storage performances of sodium niobate ceramics.

A phosphate glass Na2O-Nb2O5-P2O5 (NPP) is incorporated into NaNbO3 (NN) ceramics to examine its impact on the density, rearrangement of structural units, dielectric and energy storage features of the elaborated composites. The sodium niobate ceramic (NN) is prepared using the solid state process, whereas, the Na2O-Nb2O5-P2O5 (NPP) glasses are produced using the method of conventional melt quenching. The glass (NPP) is added to the ceramic (NN) according to the composition (100-x) NN-xNNP; (x = 0, 2.5, 5, and 7.5 %wt). The developed composites are denoted as NN-Gx where x represents the content of glass in %wt. The appropriate sintering temperature for the glass-ceramic composites was measured based on the density measurements. It was found that with the addition of glass, their density was decreased and their fritting at lower temperatures was enhanced. The obtained SST for all composites is about 900 °C. After the densification stage, Raman spectroscopy, X-ray Diffraction, Granulo-laser analysis, and scanning electron microscopy are examined to study the structural approach and the morphology of sintered NN-Gx composites. The NN-G5 composite was found to have a fine grain microstructure that was uniform. The dielectric features of the composite revealed that at ambient temperature the NN-G5 had the greatest dielectric constant. The energy storage performance of the composite was investigated from the P-E plots and the parameters of energy storage. Based on the obtained results, it was concluded that incorporating up to 5% wt. of NNP glass in sodium niobate ceramics positively affects their dielectric and energy storage performances.

Aluminate-Based Nanostructured Luminescent Materials: Design of Processing and Functional Properties.

Interest in luminescent materials has been continuously growing for several decades, looking for the development of new systems with optimized optical properties. Nowadays, research has been focused on the development of materials that satisfy specific market requirements in optoelectronics, radioelectronics, aerospace, bio-sensing, pigment applications, etc. Despite the fact that several efforts have made in the synthesis of organic luminescent materials, their poor stability under light exposure limits their use. Hence, luminescent materials based on inorganic phosphors are considered a mature topic. Within this subject, glass, glass-ceramics and ceramics have had great technological relevance, depending on the final applications. Supposing that luminescent materials are able to withstand high temperatures, have a high strength and, simultaneously, possess high stability, ceramics may be considered promising candidates to demonstrate required performance. In an ongoing effort to find a suitable synthesis method for their processing, some routes to develop nanostructured luminescent materials are addressed in this review paper. Several ceramic families that show luminescence have been intensively studied in the last few decades. Here, we demonstrate the synthesis of particles based on aluminate using the methods of sol-gel or molten salts and the production of thin films using screen printing assisted by a molten salt flux. The goal of this review is to identify potential methods to tailor the micro-nanostructure and to tune both the emission and excitation properties, focusing on emerging strategies that can be easily transferred to an industrial scale. Major challenges, opportunities, and directions of future research are specified.

Photocontrolled Strain in Polycrystalline Ferroelectrics via Domain Engineering Strategy.

The use of photonic concepts to achieve nanoactuation based on light triggering requires complex architectures to obtain the desired effect. In this context, the recent discovery of reversible optical control of the domain configuration in ferroelectrics offers a light-ferroic interplay that can be easily controlled. To date, however, the optical control of ferroelectric domains has been explored in single crystals, although polycrystals are technologically more desirable because they can be manufactured in a scalable and reproducible fashion. Here we report experimental evidence for a large photostrain response in polycrystalline BaTiO3 that is comparable to their electrostrain values. Domains engineering is performed through grain size control, thereby evidencing that charged domain walls appear to be the functional interfaces for the light-driven domain switching. The findings shed light on the design of high-performance photoactuators based on ferroelectric ceramics, providing a feasible alternative to conventional voltage-driven nanoactuators.