While β-Ga_2O_3 is considered a promising wide bandgap semiconductor, the impact of ion-induced defect formation and anisotropic elasticity remains poorly understood. Here, we combine a simulation and experiment X-ray diffraction (XRD) study of the strain-stress dynamics induced by ion implantation into β-Ga_2O_3 single-crystals with different surface orientations. The strain accumulation in the out-of-plane direction is observed by XRD to occur in an anisotropic manner, with compressive strain along the [010] direction and tensile strain along the directions perpendicular to (100) and (001). An anisotropic stress/strain accumulation model is proposed and probed via Molecular Dynamics (MD), showing an excellent agreement with the experiments. For higher damage levels, pole figures obtained both experimentally and by MD via a novel reciprocal-space projection method reveal an orientation-independent β-to-γ phase transition, with a fixed crystallographic relationship between the polymorphs. By exploring the strain-stress dynamics in anisotropic systems, this work establishes a method to directly compare macroscale diffraction experiments and atomistic simulations and opens a new path to engineer the properties of such systems utilizing their anisotropic response to ion implantation/irradiation.

A defect engineering strategy is employed to produce defective calcium-doped TiO2 nanomaterials (Ca:TiO2), which are subsequently incorporated into cellulose-based membranes. Structural defects, including vacancies, stacking faults, grain boundaries and voids emerged from the interplay between calcium doping and microwave irradiation. The 10 mol.% Ca:TiO2 membrane achieves an 81% degradation rate and an adsorption capacity of approximate to 25.8 mg g-1, showcasing excellent photocatalytic and adsorption performance. The enhanced performance is attributed to the high surface area of Ca:TiO2 agglomerates, the presence of oxygen vacancies, structural defects and the abundance of surface hydroxyl groups. X-ray Photoelectron Spectroscopy (XPS) revealed that the Fermi level of the 10 mol.% Ca:TiO2 nanomaterial is positioned near the conduction band edge, indicating a significant modification of its electronic properties, with high electrical conductivity at room temperature (RT). Density Functional Theory (DFT) calculations provided a deeper insight into the impact of calcium doping, revealing that calcium (Ca) incorporation promotes the formation of oxygen vacancies, introducing additional electronic states near the bottom of the conduction band, thereby enhancing the material's electrical conductivity. By integrating eco-friendly materials and defect-engineered nanomaterials doped with earth-abundant elements, this work aligns with sustainability principles, fostering the development of next-generation adsorptive and photocatalytic membranes.

Pharmaceutical substances are found in soils and water supplies and pose a significant risk to the ecosystem. Solar light-driven photocatalysis with titanium dioxide (TiO2) nanophotocatalysts is widely explored for degrading...

Counterfeiting is a global issue with severe economic, security, and health impacts, requiring advanced anti‐counterfeiting solutions. Luminescent materials offer unique, hard‐to‐replicate identification features. To this purpose, Y 2 GeO 5 and LiYGeO 4 samples doped with 0.5 mol% of bismuth (Bi) are synthesized by a solid‐state reaction. X‐ray diffraction and Raman spectroscopy revealed their polyphasic nature, with the samples mainly consisting of the desired crystalline phases. Photoluminescence measurements indicated that all samples exhibit a strong emission band in the ultraviolet A spectral region (355–365 nm), attributed to Bi 3+ intraionic transitions. Despite their similarities, lifetime measurements under 300 nm excitation revealed that the LiYGeO 4 sample had a lifetime nearly 100 times longer than the Y 2 GeO 5 sample. Furthermore, afterglow decay profiles demonstrated that persistent luminescence (PersL) is only observed in the LiYGeO 4 sample, detectable for over 7 h after 10 min of stimulation with 250 nm light. Longer wavelengths failed to induce PersL. This finding highlights the importance of the host material and its associated defects as trap centres that contribute to PersL. By combining these materials, multi‐level anti‐counterfeiting codes can be designed based on the differences in lifetime, PersL, and excitation energy, making them extremely difficult to replicate without specific knowledge of the materials involved.

The study on Bi-doped LiYGeO 4 PersL reveals a ∼6.05 eV direct bandgap, supported by hybrid DFT calculations. Li loss during synthesis was confirmed by elemental analysis. Excitation to the MMCT enables UV PersL (peaked @ 358 nm) for up to 7 hours.

Recently, zinc germanate (Zn2GeO4, ZGO) has emerged as a material with significant potential for various applications due to its unique optical properties. Undoped, manganese (Mn) and and chromium (Cr)-doped ZGO were synthesized through microwave-assisted hydrothermal methods. The as-synthesized and thermal annealed materials were morphological and structurally characterized, and the optical properties of these willemite prismatic nanorods were thoroughly investigated. A room temperature (RT) bandgap energy close to 236 nm (similar to 5.25 eV) was obtained, which is slightly higher than the values reported so far in the literature. Furthermore, optically active absorption and luminescence bands from the ultraviolet to near-infrared were identified. All samples present intrinsic defect absorption with a maximum at 271 nm (similar to 4.58 eV) and a charge transfer Mn2+O2- absorption band at 315 nm (similar to 3.94 eV). In addition, the so-called bluish-white structureless broad emission band is observed at RT at ca. 480 nm (similar to 2.58 eV) for all the analyzed samples. Our investigation indicates that this band is due to the overlap of two emitting centers: an intrinsic defect originating a blue luminescence (BL) and the T-4(1)->(6)A(1) intraionic transition of Mn2+ leading to a green luminescence (GL), confirming Mn as a common contaminant in this matrix. For the Cr-doped samples, the thermal annealing treatment was seen to promote changes in the visible and near infrared (NIR) intraionic absorption bands. This enabled the identification of the presence of trivalent and tetravalent Cr ion charge states. Additionally, temperature-dependent photoluminescence measurements were carried out in the case of the as-synthesized ZGO:Mn, which is the sample with the highest GL intensity. It was found that the intensity of GL decreases with temperature (from 18 K to RT), with a thermal activation energy of 18 +/- 2 meV for the nonradiative processes that compete with the observed luminescence. Moreover, persistent emission from the Mn2+ GL was recorded for at least 5 s and was attributed to multi-trapping/de-trapping processes occurring at different trap depths, which are responsible for the distinct decays observed.

The present study focuses on the sustainable synthesis of zirconium dioxide (zirconia, ZrO2) nanopowders using calcium (Ca) as a stabilizing element and microwave irradiation, eliminating the need for any post-synthesis treatment. The addition of different amounts of calcium (3, 7, and 10 mol%) influenced the ZrO2 phase transformation and further stabilization of cubic ZrO2. The synthesized nanopowders have been analyzed by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and scanning transmission electron microscopy (STEM), as well as by ultraviolet-visible (UV-VIS) and photoluminescence (PL) spectroscopies. Defective cubic ZrO2 nanocrystals (similar to 6 nm) were observed (10 mol% of Ca), featuring atomic lattice distortions and surface step defects. The higher amount of Ca also revealed an additional yellow luminescence band on PL, which can be related to intrinsic defects or impurities. The defective ZrO2 nanopowder exhibited an enhanced specific surface area of 151.62 m(2)/g, which was attributed to the presence of smaller nanocrystals associated with structural defects. As a proof of concept, the nanopowder with 10 mol% Ca was impregnated into commercial water filters to be evaluated as sustainable and cost-effective photocatalysts for the removal of tetracycline from water under solar radiation.

Zn2GeO4 (ZGeO) phosphor exhibits a wide bandgap energy, making it highly suitable for luminescence-based applications spanning the entire electromagnetic spectrum, from ultraviolet (UV) to near-infrared (NIR) wavelengths. In this work, nominally undoped and Cr-doped ZGeO (ZGeO:Cr) were prepared by solid-state reaction. X-ray diffraction and Raman spectroscopy confirmed the monophasic willemite crystalline structure of the ZGeO and ZGeO:Cr samples, and X-ray photoelectron spectroscopy corroborated the identification of Zn, Ge, O, and Cr elements. X-ray photoemission indicates an insulator character for ZGeO and ZGeO:Cr. The oxide host revealed a direct bandgap energy of 4.77 eV, assessed by room temperature absorption, in line with the density functional theory (DFT) calculations that predicted 4.8 eV at the Gamma point of the first Brillouin zone. Cr4+ was found to occupy distorted tetracoordinated Ge4+ sites with C1 symmetry, in agreement with the measured unfolded 3A2 -> 3T1, 3T2 intraionic absorption. Er3+ and Mn2+ trace impurities occupy distorted Zn2+ sites, also with C1 symmetry. A Mn2+-O2- charge transfer state, placed 0.8 eV below the conduction band minimum, was identified by absorption measurements. In addition, as calculated by DFT, Cr3+ impurities exhibit lower energy formation when placed in distorted interstitial octahedral Zn-Ge and Zn-Zn rings with C3 and S6 symmetry, respectively. The identified site locations were found to be compatible with the measured unfolded 4A2 -> 4T2, 4T1 intraionic absorption, with the ions subject to intermediate/low crystalline field strengths. The emission of the samples is dominated by structureless broad bands spanning from the visible to mid-infrared. A broad bluish-white emission results from an overlap of emitting centers related to both intrinsic defects (generating a blue emission) and trace impurities of Mn2+ (generating a green emission). Besides, Cr3+ and Cr4+ were found to coexist in the oxide host, and their multiple-site occupation is responsible for the observed broad emission bands in the NIR-I (700-950 nm) and NIR-II (1000-1700 nm) spectral regions, opening the way to the exploitation of the NIR luminescence for light-based devices.

Cr-doped Al2O3 spheres with strong red emission were produced using a simple laser processing approach with a 50 W continuous CO2 laser. Structural characterization revealed that the produced spheres were monophasic, comprising the α-Al2O3 phase. Photoluminescence (PL) studies indicated that the observed red emission originates from multiple Cr3+ optical centers being dominated by the 2E → 4A2 transition (R-lines), with a further contribution from the parity and spin forbidden 2T1 → 4A2 transition (R′-lines). The identification of additional radiative recombination from chromium ion pairs (N-lines) evidences that the produced samples are heavily doped. As such, energy transfer processes between the different chromium optical centers are seen to take place, as suggested by the lifetime decay analysis. PL excitation revealed that the room temperature luminescence is preferentially populated via the spin-allowed 4A2 → 4T2,4T1 transitions and by the parity and spin-forbidden 4A2 → 2T2 (B-lines), 2T1 (R′-lines), 2E (R-lines). Such results demonstrate that the present synthesis method is able to deliver high-optical-quality Al2O3:Cr crystals in a fast and simple way, with potential interest for optical, sensing, or lasing applications.

Counterfeit products and data vulnerability present significant challenges in contemporary society. Hence, various methods and technologies are explored for anticounterfeiting encoding, with luminescent tracers, particularly luminescent carbon dots (CDs), emerging as a notable solution. CDs offer promising contributions to product security, environmental sustainability, and the circular economy. This critical review aims to highlight the luminescence responsiveness of CDs to physical and chemical stimuli, achieved through nanoengineering their chemical structure. The discussion will delve into the various tunable luminescence mechanisms and decay times of CDs, investigating preferential excitations such as up-conversion, delayed fluorescence, fluorescence, room temperature phosphorescence, persistent luminescence, energy and charge transfer, as well as photo-chemical interactions. These insights are crucial for advancing anticounterfeiting solutions. Following this exploration, a systematic review will focus on the research of luminescent CDs' smart encoding applications, encompassing anticounterfeiting, product tracing, quality certification, and information encryption. Finally, the review will address key challenges in implementing CDs-based technology, providing specific insights into strategies aimed at maximizing their stability and efficacy in anticounterfeiting encoding applications. Several methods are proposed to combat the ever-growing issue of counterfeit products in today's market. Carbon dots (CDs) are an attractive solution, as an environment-friendly answer, and also contribute to the circular economy. This review aims to highlight CDs' luminescence tunability and their photo-chemical and photophysical responsive properties to make them relevant for anticounterfeiting and information encryption applications. image

This paper reports a comprehensive study of single-phase polycrystalline chromium-doped zinc gallogermanate (ZGGO:Cr) synthesised by a high-temperature solid-state reaction, employing photoluminescence (PL), persistent luminescence (PersL) and thermoluminescence (TL) measurements. A bandgap energy of similar to 4.77 eV (260 nm) was estimated by optical reflectance. The ZGGO:Cr luminescence was dominated by a red/near-infrared emission due to Cr3+ optical centres, which displayed well-resolved R1, R2, N1 and N2 lines, and a broad vibronic progression. PL excitation (PLE) data revealed that those centres were preferentially populated via intraionic absorption, being also excited via band-to-band absorption and by a defect excitation band at similar to 0.9 eV below the conduction band, whose origin remains unknown. PersL of more than 10 h was identified and attributed to the N2 Cr3+-related defect. The TL results suggest a continuous distribution of electronic states with activation energies ranging from about 0.7 eV to 1.2 eV. An effective density of states was obtained for different delay times between irradiation and heating, revealing a rapid depopulation for activation energies below similar to 1 eV. In short, this research contributes to a better understanding of traps in ZGGO:Cr and highlights the potential of the Cr3+-related emission in this material for dosimetric purposes, paving the way for developing novel ZGGO:Cr-based devices.

Nas últimas décadas, o Brasil experimentou uma significativa transformação nos hábitos alimentares da sociedade, acarretando impactos substanciais no estado nutricional. Este fenômeno corresponde à transição do perfil predominante, caracterizado por desnutrição e carências nutricionais, para um cenário marcado por uma considerável prevalência de obesidade e condições associadas. O objetivo deste estudo é avaliar o estado nutricional das crianças menores de 5 anos residentes da região nordeste do Brasil no ano de 2022. Trata-se de um estudo ecológico, de natureza transversal e descritiva, que fez uso de informações secundárias obtidas por meio do SISVAN-Web. Os relatórios foram gerados agrupando os estados da região Nordeste, considerando as variáveis: fase da vida “criança”, de ambos os sexos; idade “0 a < 5 anos”. Os dados foram analisados utilizando os seguintes índices nutricionais: a) peso-para-altura; b) peso-para-idade; c) idade-para-altura; e d) IMC-para-idade. Verificou-se que o Ceará possui o maior número de crianças com peso elevado para idade (n=11,47%), seguido do Rio Grande do Norte (n=10,07%) e Pernambuco (n=9,93%). O Maranhão é o estado que possui a maior prevalência de casos de altura muito baixa e altura baixa, com 8,16 e 9,08%, respectivamente. As crianças com peso adequado para idade representaram 58% da amostra, enquanto que o excesso de peso neste público perfaz o total de 34% e as que apresentaram magreza o total de 7%. Déficits nutricionais se mantêm presentes na região nordeste e ainda se comportam como problema de grande relevância em saúde pública. No entanto, dentre os agravos nutricionais, o sobrepeso e a obesidade são predominantes entre as crianças menores de cinco anos de idade. Dessa forma, faz-se necessário investir em estudos e ações que visem reduzir e combater as carências nutricionais, principalmente no âmbito da atenção primária.

Luminescent lanthanide metal-organic frameworks (LnMOF) are gathering much interest in the scientific community due to their exceptional optical properties, which have the potential to revolutionize several application fields, including anti-counterfeiting. The traceability of the original products is an ever-growing demand for producers and end-users to verify the authenticity of produced goods. Following this newfound need, we propose an anti-counterfeiting method based on a quick-response (QR) code, with a very specific verification procedure, using a luminescent LnMOF-based composite. The embedded code will only react to certain stimulation, hence it can only be unlocked using the sequence that is programmed to respond to. For that purpose, we explored the incorporation of fresh LnMOFs, with europium (EuMOF) and terbium (TbMOF), on a biodegradable polymer matrix of polylactic acid (PLA). A homogeneous mixture of PLA/LnMOF was produced via a two-step process including solvent casting followed by thermal mixing, after achieving the optimized concentration for each filler. The optical characterization of the fresh composites showed an excellent response to selective excitation, with well-defined intraionic lines for TbMOF @ 542 nm (5D4->7F5) and for EuMOF @ 615 nm (5D0->7F2). PLA/Eu, TbMOF composites were also explored to create an additional level of encryption by tuning the emitted color with the appropriate excitation stimuli. Hence, these new luminescent composite materials can be used as traceable optical tags for a wide variety of polymeric products, capable to respond to a very specific excitation wavelength and act as a level three luminescent security marker, whose decoding demands the assessment of more than one factor, with near-impossible replication. Additionally, this technology has a high potential for scalability since the applied processing techniques used for the production of the optically active QR code are commonly employed in the polymer industry. Never-theless, the analysis of the aged effects clearly indicates the need for a definition of new strategies to enhance the efficiency of the sensitization process of the Ln3+ intraionic emission. (c) 2023 Elsevier Ltd. All rights reserved.

Zinc oxide (ZnO) is a wide bandgap semiconductor material that has been widely explored for countless applications, including in biosensing. Among its interesting properties, its remarkable photoluminescence (PL), which typically exhibits an intense signal at room temperature (RT), arises as an extremely appealing alternative transduction approach due to the high sensitivity of its surface properties, providing high sensitivity and selectivity to the sensors relying on luminescence output. Therefore, even though not widely explored, in recent years some studies have been devoted to the use of the PL features of ZnO as an optical transducer for detection and quantification of specific analytes. Hence, in the present paper, we revised the works that have been published in the last few years concerning the use of ZnO nanostructures as the transducer element in different types of PL-based biosensors, namely enzymatic and immunosensors, towards the detection of analytes relevant for health and environment, like antibiotics, glucose, bacteria, virus or even tumor biomarkers. A comprehensive discussion on the possible physical mechanisms that rule the optical sensing response is also provided, as well as a warning regarding the effect that the buffer solution may play on the sensing experiments, as it was seen that the use of phosphate-containing solutions significantly affects the stability of the ZnO nanostructures, which may conduct to misleading interpretations of the sensing results and unreliable conclusions.

Europium (Eu)-implanted AlN nanowire (NW) pn junctions, subjected to rapid thermal annealing at 1000 degrees C, were investigated in view of application as red light-emitting diodes (LEDs). In a first step, the structural and optical properties of NWs implanted with two different fluences (1 x 10(14) cm(-2) and 5 x 10(14) cm(-2)) were studied. The luminescence of the trivalent Eu ions (Eu3+) was achieved for both samples using below and above AlN bandgap energy excitation. The excitation below the AlN bandgap occurs through two broad bands, A1 (peaked at similar to 270 nm) and A2 (peaked at similar to 367 nm), associated with lattice defects. In addition to Eu3+ luminescence, other radiative channels linked to deep-level defects were identified in photoluminescence (PL). The cathodoluminescence (CL) relative intensity ratio between intraionic and defect-related emissions increases compared to that of PL. In both PL and CL, the Eu3+ luminescence intensity increases about three times for the highest fluence, while the contribution from radiative recombination at defects decreases. This study also allowed to map an in-depth profile of the optically active Eu3+, revealing that it extends deeper than the range predicted by Monte Carlo simulations. Based on these findings, a proof-of-concept red LED is shown using the NWs implanted with the highest fluence. The devices exhibited the typical rectifying behavior of a p-n junction and an electroluminescence signal dominated by the D-5(0) -> F-7(2) transition (similar to 624 nm) starting at a threshold voltage of 12 V. The demonstration of red LEDs based on Eu-implanted AlN NWs highlights the potential of such an approach for developing multi-color nano-emitters.

Zinc oxide (ZnO) nanostructures have been widely used in biosensor applications. However, little attention has been given to the interaction of ZnO structures with physiological buffer solutions. In the present work, it is shown that the use of buffers containing phosphate ions leads to the modification of the ZnO tetrapodal micro/nanostructures when immersed in such solutions for several hours, even at the physiological pH (7.4). ZnO samples designed to be used as transducers in biosensors were immersed in phosphate buffers for several durations at pH = 5.8 and pH = 7.4. Their detailed morphological, structural and optical characterization was carried out to demonstrate the effect of the ZnO interaction with the phosphate ions. The pH had an important role in the ZnO conversion into zinc phosphate, with lower pH promoting a more pronounced effect. After 72 h and at pH = 5.8, a significant amount of the ZnO structures were converted into crystalline zinc phosphate, while immersion during the same time at pH = 7.4 resulted predominantly in amorphous zinc phosphate particles mixed with the original ZnO tetrapods. Photoluminescence spectra show remarkable changes with prolonged immersion times, particularly when the luminescence of the sample was investigated at 14 K. These findings highlight the importance of a careful analysis of the sensing results when phosphate-based buffer solutions are in contact with the ZnO transducers, as the changes observed on the transduction signal during sensing experiments may also comprise a non-negligible contribution from a phosphate-induced transformation of ZnO, which can hamper an accurate assessment of the sensing behavior. (c) 2021 Elsevier Ltd. All rights reserved.

Antibiotic pollution of freshwaters and even food products has become an important concern worldwide. Hence, it is of utmost importance to develop cost-effective and reliable devices that can provide information on the presence of such contaminants to the general population. In the present work, zinc oxide (ZnO) nanotetrapods (NTP) produced via a high yield laser processing approach were used as transducers in a luminescent-based immunosensor to detect tetracycline (TC). These tetrapodal structures present needle-shaped branches with a high aspect ratio, exhibiting lengths from hundreds of nanometers to a few micrometers and an average thickness of tens of nanometers, providing a high surface area for bioreceptor immobilization and analyte reaction, which is quite desirable in a transducer material. Besides, these ZnO NTP display intense photoluminescence (PL) at room temperature, making such a signal rather promising for transduction. Indeed, the intensity of the ZnO PL signal was seen to correlate with the TC concentration. The PL quenching with increasing analyte concentration is explained considering the rise in the bending of the electronic bands of the semiconductor near its surface due to increased charge density at this region, induced by the interaction between the bioreceptor (anti-TC antibodies) and the TC molecules. As a larger depletion width (and potential barrier) is promoted near the surface, the excitonic recombination probability is reduced and, consequently, the PL intensity in the ultraviolet spectral region, allowing us to use this relationship as a sensing mechanism. This information enabled us to define a calibration curve for TC quantification in the 0.001 to 1 mu g L-1 range, which is the range of interest of this antibiotic in freshwaters. A limit of detection (LOD) of similar to 1.2 ng L-1 is reported, corresponding to one of the lowest LOD found in the literature for this antibiotic, indicating that the present ZnO NTP-based biosensors rival the current state-of-the-art ones.

In situ ion-beam-induced luminescence measurements reveal a strong enhancement of the Cr3+ emission yield in electrically conductive chromium doped β-Ga2O3 single crystals upon proton irradiation. The observed effect can be explained based on the Fermi-level pinning caused by radiation defects. This pinning of the Fermi level activates deep carrier traps that can act as sensitizers of the Cr3+ emission. In agreement with this model, in semi-insulating samples, where the Fermi level lies deep in the bandgap, the Cr3+ emission is present already in as-grown samples, and no enhancement of its intensity is observed upon proton irradiation. The boost of the Cr3+ emission yield by irradiation, observed in conductive samples, is reversed by thermal annealing in argon at temperatures above 550 °C for 30 s. The results reveal a high potential of Cr-doped β-Ga2O3 for in situ and ex situ optical radiation detection and dosimetry.

The present study is focused on the synthesis of zirconium dioxide (ZrO2) nanomaterials using the hydrothermal method assisted by microwave irradiation and solution combustion synthesis. Both synthesis techniques resulted in ZrO2 powders with a mixture of tetragonal and monoclinic phases. For microwave synthesis, a further calcination treatment at 800 °C for 15 min was carried out to produce nanopowders with a dominant monoclinic ZrO2 phase, as attested by X-ray diffraction (XRD) and Raman spectroscopy. The thermal behavior of the ZrO2 nanopowder was investigated by in situ XRD measurements. From the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images, the presence of near spherical nanoparticles was clear, and TEM confirmed the ZrO2 phases that comprised the calcinated nanopowders, which include a residual tetragonal phase. The optical properties of these ZrO2 nanopowders were assessed through photoluminescence (PL) and PL excitation (PLE) at room temperature (RT), revealing the presence of a broad emission band peaked in the visible spectral region, which suffers a redshift in its peak position, as well as intensity enhancement, after the calcination treatment. The powder resultant from the solution combustion synthesis was composed of plate-like structures with a micrometer size; however, ZrO2 nanoparticles with different shapes were also observed. Thin films were also produced by solution combustion synthesis and deposited on silicon substrates to produce energy storage devices, i.e., ZrO2 capacitors. The capacitors that were prepared from a 0.2 M zirconium nitrate-based precursor solution in 2-methoxyethanol and annealed at 350 °C exhibited an average dielectric constant (κ) of 11 ± 0.5 and low leakage current density of 3.9 ± 1.1 × 10−7 A/cm2 at 1 MV/cm. This study demonstrates the simple and cost-effective aspects of both synthesis routes to produce ZrO2 nanomaterials that can be applied to energy storage devices, such as capacitors.

Acute ischemic stroke is rare in children and is associated with heart, hematologic, and vascular conditions. A high index of suspicion is required for proper diagnosis and intervention. We report a case of an acute ischemic stroke in a 13-year-old girl with a past medical history of left subscapular arteriovenous malformation. She started complaining of fever and nasal obstruction four days before admission, followed by a brief episode of blurred vision and vomiting two days later, as well as a headache on the day of admission. Facial asymmetry and slowed speech started at admission, and examination revealed right hemiparesis with homolateral facial involvement and ataxia. Magnetic resonance imaging confirmed a left pons ischemic lesion, and we started anticoagulation / anti-aggregation treatment. Angio-magnetic resonance revealed occlusion of the basilar artery and narrowing of the right vertebral artery. A complete resolution of basilar artery occlusion was noted after 40 days, while narrowing of the vertebral artery persisted. We discuss factors contributing to acute ischemic stroke and strategies to prevent future events.