DyMnO3: Synthesis, Characterization and Evaluation of Its Photocatalytic Activity in the Visible Spectrum.

DyMnO3 is a p-type semiconductor oxide with two crystal systems, orthorhombic and hexagonal. This material highlights its ferroelectric and ferromagnetic properties, which have been the subject of numerous studies. Nevertheless, its photocatalytic activity has been less explored. In this work, the photocatalytic activity of DyMnO3 is evaluated through the photodegradation of MG dye. For the synthesis of this oxide, a novel and effective method was used: polymer-decomposition. The synthesized powders contain an orthorhombic phase, with a range of absorbances from 300 to 500 nm and a band gap energy of 2.4 eV. It is also highlighted that, when using this synthesis method, some of the main diffraction lines related to the orthorhombic phase appear at 100 °C. Regarding its photocatalytic activity, it was evaluated under visible light (λ = 405 nm), reaching a photodegradation of approximately 88% in a period of 30 min. Photocurrent tests reveal a charge carrier separation (e-,h+) at a 405 nm wavelength. The main reactive oxygen species (ROS) involved in the photodegradation process were radicals, OH•, and photo-holes (h+). These results stand out because it is the first time that the photodegradation capability of this oxide in the visible spectrum has been evaluated.

Effect of Ionic Liquids in the Elaboration of Nanofibers of Cellulose Bagasse from Agave tequilana Weber var. azul by Electrospinning Technique.

The objective of this paper was to report the effect of ionic liquids (ILs) in the elaboration of nanofibers of cellulose bagasse from Agave tequilana Weber var. azul by the electrospinning method. The ILs used were 1-butyl-3-methylimidazolium chloride (BMIMCl), and DMSO was added as co-solvent. To observe the effect of ILs, this solvent was compared with the organic solvent TriFluorAcetic acid (TFA). The nanofibers were characterized by transmission electron microscopy (TEM), X-ray, Fourier transform-infrared using attenuated total reflection (FTIR-ATR) spectroscopy, and thermogravimetric analysis (TGA). TEM showed different diameters (ranging from 35 to 76 nm) of cellulose nanofibers with ILs (CN ILs). According to X-ray diffraction, a notable decrease of the crystalline structure of cellulose treated with ILs was observed, while FTIR-ATR showed two bands that exhibit the physical interaction between cellulose nanofibers and ILs. TGA revealed that CN ILs exhibit enhanced thermal properties due to low or null cellulose crystallinity. CN ILs showed better characteristics in all analyses than nanofibers elaborated with TFA organic solvent. Therefore, CN ILs provide new alternatives for cellulose bagasse. Due to their small particle size, CN ILs could have several applications, including in food, pharmaceutical, textile, and material areas, among others.

Morfología de la punta del bisel de agujas dentales post-utilización en la técnica de bloqueo del nervio alveolar inferior / Morphology of bevel's tip of dental needle post-utilization in inferior alveolar nerve block technique

Objetivo: El propósito del estudio fue evaluar la punta del bisel de 100 agujas dentales, calibre 30 corta, utilizadas en la técnica de anestesia mandibular después de 1, 2 y 3 inserciones, y de una inserción única en la que hubo contacto con hueso. Material y métodos: Se emplearon 25 agujas de cada una de las marcas: Septodont, Monoject, Hypo y Terumo, que fueron observadas al MEB, en vista de frente al bisel y de perfil, y analizadas las características de la punta. Los rasgos morfológicos registrados incluyeron punta intacta, despuntada, punta con doblez hacia el bisel y doblez hacia fuera del bisel. Los resultados se sometieron a la prueba de chi cuadrado. Resultados: Se realizaron comparaciones intra e inter-grupos, no encontrándose diferencias estadísticas significativas de acuerdo al número de inserciones y a la marca. El 15% de las agujas que no fueron insertadas presentaron alteraciones de fábrica como: porosidades del bisel, bordes aserrados y rebordes. Todas las puntas que contactaron con hueso sufrieron modificaciones. Conclusiones: Se sugiere la preferencia por las técnicas anestésicas sin contacto óseo y la consideración de que las agujas nuevas pueden presentar alteraciones

Objective: The aim of this study was to evaluate the tip of the bevel of 100 dental needles 30G short, unused, used in inferior alveolar nerve block, after 1, 2 and 3 insertions, and after a single injection with bone contact. Material and methods: Four different trademarks were evaluated (25 Septodont, 25 Monoject, 25 Hypo and 25 Terumo dental needles) and was observed in SEM, in lateral and frontal views, in order to evaluate the changes of the bevel’s tip. The morphological changes register were: intact, blunt, hooked towards bevel and hooked away bevel. Chi square test was used to compare data. Results: The groups were compared, and there were not found statistical differences between number of insertions and needle tip nor damage related to trademark. All the needles with bone contact were deformed. Results showed 15% of the unused needles had alterations. There were found manufacturing fault, in dental needles of the same lot, such as: porous bevel, blanges and serrated edges. Conclusions: Preference for non-bone contact anesthesia techniques is suggested, and consider that brand new needles may be altered