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The inverted classroom is a methodology that allows learning drivers to adapt efficiently, and in a multidisciplinary way, to the contents of the area we practice, to the objectives and to the abilities of the student, generating commitments from both the teacher and the student for their professional success. For the research, a quasiexperimental methodology was used with a student population of fifty young people of both sexes, with a control and experimental group, for whose execution four didactic procedures were carried out with their respective input-output evaluations. The analysis of variance (ANOVA) showed the permanent improvement in the learning of natural sciences with increasing trends (means) and decreasing trends (standard deviation); that is, better learning and the homogenization of the group. Studies on the subject have shown its effectiveness in learning processes and where positive reactions as well as reorientation of students are evident.

Oxyfluorotellurite glasses in the form of 60TeO2–(15–x)Li2O–25ZnO–xLiF, 65TeO2–(15–x)Li2O–20ZnO–xLiF (with x = 0, 5, 10, and 15 in mol %), and 65TeO2(20–x)Li2O–15ZnO–xLiF (x = 0, 5, 10, 15, and 20 in mol %) have been synthesized. The amorphous state of the samples was assessed using X-ray diffraction (XRD). Density, molar volume, and oxygen packing density (OPD) were measured. The thermal properties were analyzed from room temperature to 873 K using a differential scanning calorimeter (DSC). The structural and optical properties were investigated using Fourier-transform infrared (FTIR), Raman, and ultraviolet–visible (UV–Vis) spectroscopies. The results demonstrated that the OPD values decreased with increasing LiF content, and this decrease can be attributed to a decrease in the total oxygen number. The structural characterization revealed that the addition of LiF reinforces the vitreous network causing the formation of F–Te–O bonds within a more connected network. In addition, increasing the LiF content improved the glass’s thermal properties, with a decrease in the glass transition temperature and an increase in thermal stability, which facilitates the glass manufacturing process. However, this feature is dependent on ZnO concentration.

The subject of Phonology has always presented a complex learning curve. Most teachers consider it very difficult to teach the production of sounds, as well as their description to discriminate them. This, which is essential for the learning of phonology, does not receive the importance due to the cloister when this course is taught. The purpose of this research has been to demonstrate how the use of ICT positively influences the learning of phonology. The observed reality was interpreted from the positivist paradigm, using the hypothetical deductive method, with a quantitative approach, of an applied type, with an experimental design. Four treatments were applied which were evaluated with each pretest and posttest to 20 student-collaborators. These instruments were validated by seven experts. The normality test has been processed with Shapiro-Wilk (0.011). Intentional non-probabilistic sampling was used; Non-parametric statistics were used with the Wilcoxon signed rank tests, the Kruskal-Wallis test and the Bonferroni post hoc comparison tests with SPSS 26. It was shown that there are significant differences in the results of each treatment in terms of regarding the use of ICT in the learning of Phonology. The score obtained in treatment 4 was significantly better than treatment 1. Finally, there was a significant improvement between the pretest of treatment 1 (8.35) and the posttest of treatment 4 (18.40) with respect to the outstanding achievement level. on a vigesimal basis. Non-parametric statistics were used with the Wilcoxon signed rank tests, the Kruskal-Wallis test and the Bonferroni post hoc comparison tests with SPSS 26. It was shown that there are significant differences in the results of each treatment in terms of regarding the use of ICT in the learning of Phonology. The score obtained in treatment 4 was significantly better than treatment 1. Finally, there was a significant improvement between the pretest of treatment 1 (8.35) and the posttest of treatment 4 (18.40) with respect to the outstanding achievement level. on a vigesimal basis. Non-parametric statistics were used with the Wilcoxon signed rank tests, the Kruskal-Wallis test and the Bonferroni post hoc comparison tests with SPSS 26. It was shown that there are significant differences in the results of each treatment in terms of regarding the use of ICT in the learning of Phonology. The score obtained in treatment 4 was significantly better than treatment 1. Finally, there was a significant improvement between the pretest of treatment 1 (8.35) and the posttest of treatment 4 (18.40) with respect to the outstanding achievement level. on a vigesimal basis. It was shown that there are significant differences in the results of each treatment regarding the use of ICT in the learning of Phonology. The score obtained in treatment 4 was significantly better than treatment 1. Finally, there was a significant improvement between the pretest of treatment 1 (8.35) and the posttest of treatment 4 (18.40) with respect to the outstanding achievement level. on a vigesimal basis. It was shown that there are significant differences in the results of each treatment regarding the use of ICT in the learning of Phonology. The score obtained in treatment 4 was significantly better than treatment 1. Finally, there was a significant improvement between the pretest of treatment 1 (8.35) and the posttest of treatment 4 (18.40) with respect to the outstanding achievement level. on a vigesimal basis.

In recent years, infrared emitting luminescence nanothermometers have attracted significant attention because their potential for the development of new diagnosis and therapy procedures. Despite their promising applications, concerns have been...

Un método de adsorción utilizando la resina Dowex™Marathon™ WBA ha sido desarrollado con el fin de evaluar larecuperación de ácido cítrico producido por fermentación sumergida. Para determinar la viabilidad de este método de separación, la resina fue evaluada a diferentes condiciones de temperatura (30 – 70 °C) y pH (1.5 – 6.5). Los resultadosmostraron que a pH bajo, se mejora la adsorción de ácido cítrico, a través de la cual, se recupera el 85% del ácido y se obtiene una pureza del 92%. Esto representa una capacidad máxima de adsorción de 0.46 g de ácido cítrico por gramo de resina empleada.

This study aimed to evaluate the physical–chemical properties (particle size, zeta potential, encapsulation, and thermal stability), antioxidant properties, antibacterial properties and casein-flavonoid interaction studies of soluble complexes, called caseinates of red propolis. The caseinates of red propolis were successfully prepared using the spray-dryer technique, which presented two populations of nanometre and micrometre particles, and were able to encapsulate flavonoids and isoflavonoids from the red propolis extract as a soluble complex. SEM analysis demonstrated casein nanoparticles and fat globules combined with lipophilic compounds (terpenes) from red propolis extract. FTIR analysis proved the encapsulation of flavonoids into caseinates. The thermogravimetric assays demonstrated thermal stability of red propolis caseinates and DTA analysis observed the denaturation during the coagulation temperature. The fluorescence, antioxidant, Folin–Ciocalteu method and chromatographic assays have shown that flavonoids bind to the amino acid residues present in the casein protein matrix, demonstrating a reversible interaction between flavonoids and casein amino acids. Dissolution studies prove the formation of a casein-flavonoids soluble complex and can bring benefits and increase the process of absorption of flavonoids by biological membranes. Despite the interaction of flavonoids with casein amino acids, caseinates of red propolis demonstrated antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. The caseinates of red propolis can be easily incorporated in foods such as cakes, pies, dairy and cocoa such as foods bio-preservatives. The caseinates of red propolis can be manufactured by the pharmaceutical and nutraceuticals industries as intermediary bioproduct in the powder form for supplements, capsules and oral emulsion systems for beverages as yogurts.

Este artigo investiga o processo de preservação arquitetônica a partir da aplicação de técnicas fotogramétricas para a documentação digital. Adotou-se, como objeto empírico, a Igreja Nossa Senhora Mãe dos Homens, localizada em Coqueiro Seco, no estado de Alagoas, Brasil. Datada de 1790, consiste em um dos exemplares da arquitetura religiosa mais antigo do estado, protegida pela União por meio do tombamento desde 2011 e com previsão de uma obra de restauro em suas estruturas. O objetivo deste artigo é documentar o estado anterior à intervenção na igreja, descrevendo o processo de documentação patrimonial e utilizando como recurso técnicas fotogramétricas mistas. Metodologicamente, foram realizadas pesquisas bibliográficas e documentais; levantamentos fotográficos da Igreja, seguindo os princípios da restituição fotogramétrica interativa e do Dense Stereo Matching (DSM); construção de modelos geométricos por meio do software PhotoModeler Scanner e vetorização das fachadas utilizando-se uma ferramenta CAD. Como resultados, registraram-se as fachadas principais do bem com a fotogrametria e disponibilizou-se a documentação produzida. Além disso, o artigo traz uma reflexão acerca das limitações das técnicas utilizadas, enfatizando a relevância do uso híbrido das tecnologias disponíveis para o registro e democratização do acesso à documentação da arquitetura de interesse cultural.

We report the microwave-assisted synthesis of binary doped optical-magnetic up/downconverting NaGdF4:RE and iron oxide/SiO2/NaGdF4:RE nanoparticles. The morphological characteristics were finely tuned from elongated rod-shaped to ovoidal nanoparticles. The (Yb, and Er) activated particles provided an excellent up/down conversion luminescence emission in the green and mid-infrared region under excitation of 980 nm, whereas the (Ce, and Eu) activated systems exhibited a strong red emission via the Gd3+ sublattice upon excitation in the UV region. The magnetic hysteresis at 300 K for β-NaGdF4:RE showed typical signatures of a paramagnetic system, whereas iron oxide/SiO2/β-NaGdF4:RE exhibited superparamagnetic behavior along with a Curie-like component. The luminescence quenching effects induced by the presence of iron oxide phase have been validated through comparing the emission/lifetime decay curves. In addition to the excellent optical and magnetic properties, these materials show remarkably high longitudal and transverse relaxivity values (for Fe and Gd) and thus are potential candidates for T1 and T2-weighted bioimaging.

Hexagonal LaF3:Yb3+/Ln3+ and tetragonal LaOF:Yb3+/Ln3+ (Ln = Ho, Tm, Er) have been successfully prepared via a two-step reaction, which includes a facile aqueous ligand free solution method and the following heat treatment of the as-prepared LaF3 precursor. The phase formation evolution from LaF3 to LaOF with different phase structures was characterized by X-ray diffraction (XRD), scanning electron microscopy, Fourier transform infrared, and Raman spectroscopy. At an annealing temperature of 500 °C pure hexagonal LaF3:Yb3+/Ln3+ (Ln = Ho, Tm, Er) nanoparticles with an average size of 32 nm were obtained and they showed a strong visible upconversion and a modest infrared emission upon 976 nm laser excitation. Further, using an annealing temperature of 900 °C, tetragonal LaOF:Yb3+/Ln3+ (Ln = Ho, Tm, Er) nanoparticles with a size of around 44 nm were obtained (obtained from XRD) and an expressive enhancement in the emission of the VIS and near-infrared regions was observed. These results envision applications that require efficient emissions such as fluorescent and thermal images, and LaF3 nanocrystals have recently been widely explored for applications in biological systems.

We demonstrate the feasibility of an unconventional excitation of Nd3+ at 1064 nm by a photon-avalanche-like mechanism, which involves an energy looping due to energy transfer among excited Nd3+ followed by resonant excited-state absorption.

Freeze- and spray-dried inclusion complexes (ICs) of chlorhexidine (CHX) in β-cyclodextrin were characterized by Fourier transform (FT)-Raman, 1H nuclear magnetic resonance (NMR), and photoacoustic spectroscopy. The active Raman modes of CHX were simulated using the density functional theory. By considering semiempirical calculations, it was observed that the guest penetrates on the wider rim of the host in a proportion of 1:2. We observe from the FT-Raman analysis that the drying method influences the CHX:β-cyclodextrin conformational adjustment by the rearrangement of hydrophilic biguanides of the guest. The photoacoustic spectroscopy results inferred that the freeze-drying method provided a better inclusion due to a lower interaction between phenyl groups and hexamethylene of CHX. The freeze-dried IC achieved a faster dissolution pattern. These ICs provided immediate drug dissolution profiles in an aqueous medium better than a pure drug. The release profiles of freeze- and spray-dried ICs were explained by Fickian diffusion. These data support further planning and development projects of novel immediate release systems based on CHX.

In recent years, an unconventional excitation of trivalent neodymium ions ( N d 3 + ) at 1064 nm, not resonant with ground-state transitions, has been investigated with the unprecedented demonstration of a photon-avalanche-like (PA-like) mechanism, in which the temperature increase plays a fundamental role. As a proof-of-concept, N d A l 3 ( B O 3 ) 4 particles were used. A consequence of the PA-like mechanism is the absorption enhancement of excitation photons providing light emission at a broad range covering the visible and near-infrared spectra. In the first study, the temperature increase was due to intrinsic nonradiative relaxations from the N d 3 + and the PA-like mechanism ensued at a given excitation power threshold ( P t h ). Subsequently, an external heating source was used to trigger the PA-like mechanism while keeping the excitation power below P t h at room temperature. Here, we demonstrate the switching on of the PA-like mechanism by an auxiliary beam at 808 nm, which is in resonance with the N d 3 + ground-state transition 4 I 9 / 2 → { 4 F 5 / 2 , 2 H 9 / 2 } . It comprises the first, to the best of our knowledge, demonstration of an optical switched PA, and the underlying physical mechanism is the additional heating of the particles due to the phonon emissions from the N d 3 + relaxation pathways when exciting at 808 nm. The present results have potential applications in controlled heating and remote temperature sensing.

In this work, we report a potential nanothermometer with high thermal sensitivity based on sodium niobate (NaNbO3) nanocrystals doped and co-doped with Tm3+ and Tm3+/Yb3+, respectively, synthesized by the Pechini (sol–gel) method. Under anti-Stokes excitation (1064 nm) it was investigated the fluorescence intensity ratio ( F I R = I 700 n m / I 660 n m ) of the 700 nm (3F2,3 → 3H6) and 660 nm (1G4 → 3F4) emissions, which are within the first biological window, as a function of temperature in the 300–493 K range. Relative thermal sensitivities constant with the temperature were obtained, with values of 1.60% K−1 and 1.86% K−1 for NaNbO3:1%Tm3+ and NaNbO3:1%Tm3+/1%Yb3+ samples, respectively, which is the highest value in the literature for Tm3+/Yb3+ co-doped system under 1064 nm excitation. The importance of the anti-Stokes excitation relies on the fact that emissions (up and downconversion) in general increase with the temperature, making possible obtaining fluorescence and thermal images with better resolutions. Additionally, as both excitation and emission are within the biological windows, these nanoparticles might be useful for biological applications.

Orthorhombic sodium niobate (NaNbO3) nanocrystals, transparent in the visible and near-infrared, were synthesized by using the Pechini's sol-gel method. Experiments were performed to measure the first hyperpolarizability of the nanoparticles by using a pulsed laser operating at 1064 nm. The hyper-Rayleigh scattering technique was used to analyze the second harmonic scattered light generated by the nanocrystals. By using the external reference method, with para-nitroaniline as the standard reference, we determined the NaNbO3 hyperpolarizability per nanoparticle volume (0.93 × 10−29 esu/nm3) for the first time, and show that the effective second-order susceptibility has the same order-of-magnitude as LiNbO3 and KNbO3 nanocrystals.

An extension of Drude–Lorentz model based on the fractional approach was used to investigate quantitative measurement of refractive index as a function of wavelength of Tellurite glasses. Tellurite glass samples were synthesized by conventional melt-quenching method with the composition of 65TeO2–15Li2O–20ZnO undoped and doped with different concentrations of Er2O3. Refractive index measurements were performed using the Brewster angle technique with polarized lasers at 442, 532, 594 and 633 nm as light source. From the Sellmeier’s coefficient it was possible to obtain the behavior of refractive index from 0.35 to 1.8 μm. The analytical solution obtained from the generalized Drude–Lorentz model was used to investigate the experimental data of refractive index behavior obtained by the two-pole Sellmeier’s equation showing that the mean polarizability increases with Er2O3 concentration and this behavior can be related to a collective fractal character of the material.

Er3+ ions doped oxyhalide barium borate glasses were prepared by means of conventional melt quenching technique. In the studied glass system, besides the Er3+ doping, barium oxide was partially replaced by BaF2 and/or BaCl2. The amorphous nature of as-prepared glasses was confirmed by X-ray diffraction patterns. The effects of the compositional changes were investigated through spectroscopic techniques such as optical absorption, emission and decay lifetime. It was found that the luminescence and decay lifetime of Er3+: 4I13/2 → 4I15/2 transition are affected by both Er3+ doping and halide insertions. By applying the Judd-Ofelt (JO) theory, the JO intensity parameters (Ωt, t = 2, 4, and 6) were calculated, and the trend Ω2 > Ω4 > Ω6 was found, which is in accordance with previous studies. Optical properties such as electric and magnetic dipole transition probabilities, fluorescence branching ratios, integrated emission cross sections and radiative lifetimes were also obtained and discussed for many excited states of Er3+ ions. The lifetime of the 4I13/2 excited level was measured and compared with the calculated one.

Recently, mixed-former glasses have attracted a large attention due to the appropriate combinations of the chemical, physical and optical properties of each glass former. In this scenario, the optical properties of fluoroborate glasses doped with rare earth ions is of importance due to their good transparency window from ultra-violet to near-infrared region, good rare-earth solubility, long excited state lifetime of such ions, and high mechanical strength. In this work, we had studied the optical properties of the Tb3+ doped fluoroborate glasses, focusing on the concentration dependent behavior of luminescence dynamics of 5D3 and 5D4 exited states of this ion. The blue-to-green intensity ratio, lifetime of the emitting levels under various excitation wavelengths, cross-relaxation rate, ion-ion critical distance and emission gain bandwidth are calculated.

The use and applications of infrared emitting rare-earth luminescent nanoparticles as nanothermometers have attracted a great deal of attention during the last few years. Researchers have regarded rare-earth doped luminescent nanoparticles as appealing systems due to their reliability, sensitivity and versatility for minimally invasive thermal sensing in nanomedicine. The challenge of developing nanothermometers operating over 1000 nm with outstanding brightness and enhanced sensitivity is being constantly addressed. In this sense, this work explores the potential of Tm3+ emissions at around 1.23 and 1.47 μm, under excitation at 690 nm, for ratiometric thermometry in Tm3+ doped LaF3 nanoparticles. The temperature dependence of the 1.23 μm emission band, which cannot be observed in systems such as NaNbO3:Tm, was demonstrated to be very effective and presented a relative thermal sensitivity as high as 1.9% °C−1. The physical mechanisms behind the strong thermal dependences were explained in terms of multiphonon decays and cross-relaxations. As a proof of concept, the nanothermometers presented were capable of accessing the basic properties of tissues in an ex vivo experiment using thermal relaxation dynamics.

T m 3 + / H o 3 + -codoped low silica calcium aluminosilicate (LSCAS) glasses were prepared and characterized using optical absorption, luminescence decay, and thermal lens techniques. The emission band at 2.0 µm exhibited an enhancement when the Ho concentration was increased. The luminescence quantum efficiency values were determined for both 3 F 4 and 5 I 7 levels of T m 3 + and H o 3 + ions, respectively. The high decrease of the quantum efficiency of the 3 F 4 ( T m 3 + ) level for high H o 3 + concentration evidenced efficient energy transfer processes from T m 3 + to H o 3 + . The heat generated in the energy transfer processes were estimated via a thermal lens experiment, and a rate equation model was proposed to explain the obtained result. The experimental and estimated parameters with the proposed theoretical model are in good agreement. Finally, the results of this work suggest the T m 3 + / H o 3 + -codoped LSCAS is a promising material for applications using the emission around 2.0 µm that is of great interest for biomedical applications.

Supporting Information

Photon avalanche (PA) is a fascinating mechanism for exciting trivalent rare-earth ions (REI3+). It occurs when cross-relaxation mechanisms provide a non-zero population at a lower excited state. Then, photons that are nonresonant with ground-state transitions can be increasingly absorbed from this level. PA has been demonstrated with some REI3+-doped materials under specific excitation wavelengths and temperature regimes. Here the PA-like was observed on NdAl3(BO3)4 particles at some fixed temperature values (within 23 °C ≤ T ≤ 215 °C), while the excitation power was increased. In this study, the PA-like is associated to a cross-relaxation mechanism [4F3/2, 4I9/2] → [4I15/2, 4I15/2]. After multiphonon emissions, the population of Nd3+ ions at the 4I11/2 state doubles at every iteration, a process followed by a resonant excited-state absorption (4I11/2 → 4F3/2). In this case, the excitation power threshold decreased threefold. In a second round of experiments, we demonstrate for the first time the triggering the PA-like mechanism by increasing the temperature (27 °C ≤ T

Hexagonal LaF

12 p.-5 fig., Optical probes operating in the second near-infrared window (NIR-II, 1,000-1,700 nm), where tissues are highly transparent, have expanded the applicability of fluorescence in the biomedical field. NIR-II fluorescence enables deep-tissue imaging with micrometric resolution in animal models, but is limited by the low brightness of NIR-II probes, which prevents imaging at low excitation intensities and fluorophore concentrations. Here, we present a new generation of probes (Ag2S superdots) derived from chemically synthesized Ag2S dots, on which a protective shell is grown by femtosecond laser irradiation. This shell reduces the structural defects, causing an 80-fold enhancement of the quantum yield. PEGylated Ag2S superdots enable deep-tissue in vivo imaging at low excitation intensities (, Authors thank Dr A. Benayas (CICECO, U. Aveiro, Portugal), Prof G. Lifante and Prof J. García Sole (UAM) for helpful discussions. This work has been founded by Ministerio de Economı́a y Competitividad-MINECO (MAT2017-83111R and MAT2016-75362-C3-1-R) and the Comunidad de Madrid (B2017/BMD-3867 RENIM-CM) co-financed by European Structural and Investment Fund. D.M.-G. thanks UCM-Santander for a predoctoral contract (CT17/17-CT18/17). We thank the staff at the ICTS-National Centre for Electron Microscopy at the UCM for the help in the electron microscopy studies and C.M. at the beamline BL22-CLAESS of the Spanish synchrotron ALBA for his help in the XANES experiments. We also thank J.G.I at the Ultrafast Laser Laboratory at UCM for his help and fruitful discussion. Y.S. acknowledges the support from the China Scholarship Council (CSC File No. 201806870023). Additional funding was provided by the European Commission Horizon 2020 project NanoTBTech, the Fundación para la Investigación Biomédica del Hospital Universitario Ramón y Cajal project IMP18_38 (2018/0265). Ajoy K. Kar and Mark D. Mackenzie acknowledge support from the UK Engineering and Physical Sciences Research Council (Project CHAMP, EP/M015130/1). C. Jacinto thanks the financial support of the Brazilian agencies: CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) through the grants: Projeto Universal Nr. 431736/2018-9 and Scholarship in Research Productivity 1C under the Nr. 304967/20181; FINEP (Financiadora de Estudos e Projetos) through the grants INFRAPESQ-11 and INFRAPESQ-12; FAPEAL (Fundação de Amparo à Pesquisa do Estado de Alagoas) grant Nr. 1209/2016. H. D. A. Santos was supported by a graduate studentship from CNPq and by a sandwich doctoral program (PDSE-CAPES) developed at Universidad Autonoma de Madrid, Spain, Project Nr. 88881/2016-01.