This paper reports on the preparation of novel sol-gel erbium-doped SiO2-based nanocomposites embedded with Nb2O5 nanocrystals fabricated using a bottom-up method and describes their structural, ...morphological, and luminescence characterization. To prepare the glass ceramics, we synthesized xerogels containing Si/Nb molar ratios of 90:10 up to 50:50 at room temperature, followed by annealing at 900, 1000, or 1100 °C for 10 h. We identified crystallization accompanying host densification in all the nanocomposites with orthorhombic (T-phase) or monoclinic (M-phase) Nb2O5 nanocrystals dispersed in the amorphous SiO2 phase, depending on the niobium content and annealing temperature. A high-intensity broadband emission in the near-infrared region assigned to the 4I13/2 → 4I15/2 transition of the Er3+ ions was registered for all the nanocomposites. The shape and the bandwidth changed with the Nb2O5 crystalline phase, with values achieving up to 81 nm. Er3+ ions were located mainly in Nb2O5-rich regions, and the complex structure of the different Nb2O5 polymorphs accounted for the broadening in the emission spectra. The materials containing the T-phase, displayed higher luminescence intensity, longer 4I13/2 lifetime and broader bandwidth. In conclusion, these nanostructured materials are potential candidates for photonic applications like optical amplifiers and WDM devices operating in the S, C, and L telecommunication bands.
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•Rare earth doped Nb2O5 nanocrystals prepared from a bottom-up approach.•Unusual broadband NIR emission in glass ceramic system.•Structural features tuning the luminescence properties.•Potential as optical amplifiers and WDM devices.•Photonic devices operating in the S, C, and L telecommunication.
The rising demand for more efficient telecommunication networks that can carry larger data volume is currently one of the most pressing technological challenges. In this sense, developing new ...materials to obtain NIR broadband emission is an urgent matter. We have successfully prepared Tm3+/Yb3+ co-doped 70SiO2-30Nb2O5 and 70SiO2–30Ta2O5 (mol%) nanocomposites by the sol–gel method. The Tm3+/Yb3+ co-doped 70SiO2-30Nb2O5 and 70SiO2-30Ta2O5 nanocomposites displayed intense broad emission that extends from 1.6 to 2.1 µm, with maximum at 1.8 µm. The bandwidth values lied around 230 or 260 nm depending on the crystalline phase. Increasing rare earth content elicited discrete quenching, which attests to good rare earth solubility and distribution within the hosts. The luminescence results are outstanding in terms of silicate hosts and point to the potential application of these materials in optical amplifiers, remote sensing, and LIDAR systems.
Introduction: Food and nutrition are fundamental in maintaining the general and oral health of populations. Health status can be affected by nutrient deficiency and vice versa. Dietary guidelines ...were developed to provide evidence-based food and beverage recommendations to populations to promote a diet that meets nutritional needs and prevents diet-related illness. Objective: Aimed to carry out a concise systematic review to elucidate through clinical studies the real relationship between nutrition and oral health. Methods: The rules of the Systematic Review-PRISMA Platform. The research was carried out from August to October 2022 and developed based on Scopus, PubMed, Science Direct, Scielo, and Google Scholar, using scientific articles from 2005 to 2022. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: A total of 125 articles were found. In total, 75 articles were fully evaluated and 35 were included and evaluated in this systematic review. It was concluded that food and nutrition are fundamental in maintaining the general and oral health of populations. Health status can be affected by nutrient deficiency and vice versa. Nutrology can promote a diet that meets nutritional needs and prevent diet-related diseases such as tooth decay. It was evidenced that malnutrition can significantly affect oral health and vice versa. A diet lacking in nutrients can lead to the progression of oral cavity disease by altering tissue homeostasis, reducing resistance to microbial biofilm, and decreasing tissue healing. It can also affect the development of the oral cavity.
A new sol–gel route was used for obtaining Er3+/Yb3+ co-doped Nb2O5 nanoparticles distributed in a SiO2 based host. Phase separation and crystallization process were investigated for Er3+/Yb3+ ...co-doped nanocomposites at 70Si:30Nb molar ratio. X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier transform infrared (FTIR), Raman, and Photoluminescence (PL) spectroscopy were used to assess the structural properties and their influence on luminescence. Amorphous Nb2O5 was identified after nanocomposite annealing at 700°C, whereas at 900°C and 1100°C were identified both the orthorhombic and monoclinic phases. The average crystallite sizes were 6.6nm at 900°C and 16.4nm at 1100°C. Intense and broad NIR emission was observed for the nanocomposites annealed at 700 and 900°C due to an efficient energy transfer from Yb3+ to Er3+ ions. Intense emissions at 980nm and 1550nm were also observed due to energy transfer from the host to Yb3+ and Er3+ ions, respectively. Additionally, a less efficient back energy transfer from Er3+ to Yb3+ ions was observed. The emission intensity and bandwidth were dependent on the nature of Nb2O5 crystalline phase, indicating that rare-earth (RE) ions are mostly distributed into Nb2O5 nanoparticles. The 4I13/2 and 2F5/2 excited state lifetimes were also dependent on Nb2O5 crystalline phase with shorter values for monoclinic Nb2O5. The featured luminescent properties exhibited by the rare earth-doped Nb2O5 make the nanocomposite materials potential candidates in many photonic applications.
A utilização da mecanização agrícola tornou mais eficiente as práticas agrícolas, destacando-se o trator que permitiu a realização de práticas de cultivo mais eficientes. Portanto, objetivou-se ...determinar o comprimento de talhão que obtenha eficiência de campo de 90% na operação de preparo do solo com grade média em função da velocidade de deslocamento e do comprimento do talhão. O experimento foi realizado em delineamento inteiramente casualizado, em esquema fatorial 8x3, com seis repetições, totalizando 96 observações. O primeiro fator foram oito comprimentos de talhões (30, 60, 90, 120, 150, 180, 210 e 240 m). O segundo foram três velocidades de deslocamento (3,0; 4,1 e 4,7 km h-1). Com os dados de rendimento de campo efetivo foi gerado uma curva de resposta para seleção do comprimento de talhão que proporcione rendimento de campo efetivo de 90%. No fator velocidade de deslocamento a maior capacidade de campo operacional ocorreu com 4,7 km h-1. Para o fator comprimento do talhão a maior capacidade de campo operacional e rendimento de campo efetivo foi observada com 240 m. O rendimento de campo efetivo de 90% é alcançado com comprimento de talhão de 120 metros. A capacidade de campo máxima ocorreu com a velocidade de 4,7 km h-1 (0, 93 ha h-1) com o comprimento de talhão de 214 m.
The use of agricultural mechanization has become more efficient in several agricultural practices, highlighting the tractor as the main machine used in carrying out these activities, thus allowing ...more efficient cultivation practices. The objective was to determine the field length that obtains field efficiency of 90% in the soil tillage operation with a medium harrow depending on the displacement speed and the length of the field. The experiment was carried out in a completely randomized design, in an 8x3 factorial scheme, with six replications, totaling 96 observations. The first factor was eight field lengths (30, 60, 90, 120, 150, 180, 210 and 240 m). The second was three travel speeds (3.0; 4.1 and 4.7 km h-1). With the effective field yield data, a response curve was generated to select the field length that provides an effective field yield of 90%. In the displacement speed factor, the greatest operational field capacity occurred with 4.7 km h-1. For the field length factor, the greatest operational field capacity and field yield effective was observed with 240 m. The effective field yield of 90% is achieved with a field length of 120 meters. Maximum field capacity occurred at a speed of 4.7 km h-1 (0.93 ha h-1) with a field length of 214 m.
We have investigated how the Nb content influences the structural and luminescence properties of Er3+/Yb3+ co-doped SiO2–Nb2O5 nanocomposites prepared by an alternative sol-gel process at different ...Si/Nb molar ratios of 90:10 up to 20:80. X-ray diffraction (XRD), Transmission electron microscopy (TEM), Diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), and Photoluminescence spectroscopy (PL) provided a detailed structural and spectroscopic analysis of the composites. Formation of the Nb2O5 crystalline phases depended on the Si/Nb ratio. Nanocomposites with 20 up to 40 and 80mol% of Nb contained the T crystalline phase, whereas nanocomposites with 50mol% of Nb presented both the T and M crystalline phases. The average crystallite size increased from 5.9nm to 33.8nm as the niobium content, as revealed by XRD. The λcutoff increased with the Nb content, and the band gap energy ranged from 4.27eV to 3.54eV. Full elimination of OH groups was suitable for the highest Nb concentrations, which influenced the luminescence properties. Efficient Yb3+ → Er3+ energy transfer occurred under 977-nm excitation, leading to broad and intense 1.5-µm emission for Nb30 and Nb40, with FWHM of 67nm and 69nm, respectively. Under 520-nm and host excitations, Er3+ and Yb3+ emissions at 1.0µm took place. The different Nb2O5 crystalline phases influenced the energy transfer processes between Er3+ and Yb3+ ions, which affected the relative intensity of the 1.0/1.5-μm emissions. Tuning of this relative intensity is possible depending on the Nb content, which paves the way for the application of these nanocomposites as optical amplifiers at 1.5μm, solid-state lasers and energy converters. The Er3+/Yb3+ co-doped nanocomposites with 30 and 40mol% of Nb amount displayed the most promising luminescence properties for photonic applications.
According to the World Health Organization (WHO), latent tuberculosis occurs through latent infection by Mycobacterium tuberculosis without evidence of active tuberculosis (TB) symptoms. As patients ...don’t develop the same symptoms as active TB, the treatment is abandoned before the end, as it lasts about six months. This leads to significant treatment avoidance, requiring new forms of adherence to latent TB treatment. One of the strategies to help to latent TB treatment is the possibility of using applications for mobile devices, once the use of ICTs to aid in the treatment of LTBI can increase the rate of treatment adherence. Thus, this work aimed to study the creation of a technology that helps the adherence of these patients, being made available an application that is easy to use, intuitive, free and developed in a language for Android phones, which accompany the patient throughout the treatment.
This work reports on the Yb3+ ion addition effect on the near infrared emission and infrared-to-visible up conversion from planar waveguides based on Er3+–Yb3+ co-doped Nb2O5 nanocrystals embedded in ...SiO2-based nanocomposite prepared by a sol–gel process with controlled crystallization in situ. Planar waveguides and xerogels containing Si/Nb molar ratio of 90:10 up to 50:50 were prepared. Spherical-like orthorhombic or monoclinic Nb2O5 nanocrystals were grown in the amorphous SiO2-based host depending on the niobium content and annealing temperature, resulting in transparent glass ceramics. Crystallization process was intensely affected by rare earth content increase. Enhancement and broadening of the NIR emission has been achieved depending on the rare earth content, niobium content and annealing temperature. Effective Yb3+→Er3+ energy transfer and a high-intensity broad band emission in the near infrared region assigned to the Er3+ ions 4I13/2→4I15/2 transition, and longer 4I13/2 lifetimes were observed for samples containing orthorhombic Nb2O5 nanocrystals. Intense green and red emissions were registered for all Er3+–Yb3+ co-doped waveguides under 980nm excitation, assigned to 2H11/2→4I15/2 (525nm),4S3/2→4I15/2 (545nm) and 4F9/2→4I15/2 (670nm) transitions, respectively. Different relative green and red intensities emissions were observed, depending upon niobium oxide content and the laser power. Upconversion dynamics were determined by the photons number, evidencing that ESA or ETU mechanisms are probably occurring. The 1931 CIE chromaticity diagrams indicated interesting color tunability based on the waveguides composition and pump power. The nanocomposite waveguides are promising materials for photonic applications as optical amplifiers and WDM devices operating in the S, C, and L telecommunication bands; and as upconverter materials for visible upconversion lasers, biomedical applications, energy conversion for solar cells and others.
•Unusual broadband NIR emission in nanocomposites and planar waveguides.•Strong effect of Yb 3+ on enhancement and broadening of NIR emission.•Multicolor tunability of intense upconversion emission from planar waveguides.
Non-compliance with latent tuberculosis infection (LTBI) treatment is a reality. The objective of this study was to develop and validate an mobile device application for monitoring the treatment of ...LTBI.
We defined the requirements, elaborated on the application's conceptual map, generated implementation and prototyping alternatives, and validated content.
Feedback on the validity of content were: "usefulness, consistency, clarity, objectivity, vocabulary, and precision" from professionals, and "clarity" from patients.
The application proved to be easy to understand, according to the assessment of both professionals and people undergoing treatment for LTBI.
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