Search

Visible-light photoactive (Na0.5Bi0.5)TiO3 (NBT)-based heterojunctions have demonstrated their applicability in environmental remediation. The photocatalytic properties of NBT-based coatings are here reported. NBT-based materials were deposited by oxyacetylene flame spray (FS). The physicochemical properties were analyzed as a function of the spraying parameters: fuel/oxygen ratio (F/O), stand-off distance (SOD), and total gas flow (TF). A flame with reducing characteristics promotes the formation of TiO2 (anatase and rutile) and Bi4Ti3O12, while an oxidizing flame results in coatings rich in NBT and Bi4Ti3O12. The SOD mainly influences the degree of crystallinity, which is higher at shorter distances. Optical properties estimated by UV–VIS diffuse reflectance confirmed an increase in light absorption after the FS process, with an Eg red shift from 3.32 eV of the NBT powder to 2.63-2.96 eV of the coatings. These values are dependent on the F/O, with a significant Eg narrowing under reducing conditions. Photoelectrochemical measurements revealed that faster electron collection is obtained due to the transformations occurring throughout the FS process while still retaining nearly 70 and 88% of the photocurrent density (jph) at UV and visible light, respectively. These results suggest the great potential of the FS methodology to produce multiphase photocatalytic coatings by tuning the processing parameters. [ABSTRACT FROM AUTHOR]

Clinical reasoning as cognitive process regulator of medical diagnosis has experienced considerable changes through the history. This work is intended to carried out a historical description of clinical reasoning, to contribute in the reinforcement of its relevance as rational component of the clinical method, responsible to a great extent, of the medical diagnosis efficiency. The study covered the transformations of the clinical reasoning from the Ancient times to the Contemporary Age, taking into account the main effective philosophical tendencies existing in each period. It was concluded that the description of the stream of consciousness related to the reasoning through the historical and philosophical development of humanity favors to keep the postulates of the clinical reasoning in line with the medical practice and the teaching-learning process of the clinical subjects in the contemporary conceptions. [ABSTRACT FROM AUTHOR]

The development of skills related to clinical problems occupies a central site in the teaching-learning process of medical education, due to its special meaning in the general doctor professional performance. Due to the absence of this skill in the curriculum of the medicine career, this reflection study was carried out with the objective of supporting its incorporation to the skills system of the clinical method in the Cuban medical education. On the other hand, the skill in question was defined and its functional invariants were determined; that when being part of a methodological procedure, facilitate their integration to the system of teaching-learning methods to be used in the different forms of organization of the subjects that integrate the main discipline of the study plan D. [ABSTRACT FROM AUTHOR]

Compressive strength, micro-hardness indentation, friction, and wear tests of the poly(methyl methacrylate)/hydroxyapatite nanocomposite have been performed and evaluated in order to study the potential application of this nanocomposite in the field of bone tissue regeneration. PMMA/HA nanocomposite in the form of bulk has been successfully prepared by a simple mixture between PMMA and HA nanoparticles. The compressive strength value of PMMA/HA nanocomposite was found to be ∼90 MPa; whereas the compressive Young’s modulus was 840 MPa, and the micro-hardness obtained was 55 MPa. According to the results, PMMA/HA nanocomposite exhibit an acceptable elastic modulus for its possible consideration in the tissue engineering. The wear rate value of the nanocomposite PMMA/HA was found to be at the same magnitude for its similar applied as coating reported previously, while friction coefficients showed higher values. [ABSTRACT FROM AUTHOR]

Currently, the large volumes of Sargassum biomass (Sgs) arriving on Caribbean coasts are a problem that must be solved quickly. One alternative is to obtain value-added products from Sgs. In this work, Sgs is demonstrated to be a high-performance Ca - bioadsorbent for phosphate removal by a heat pretreatment at 800 °C that produces biochar. According to XRD analysis, calcined Sgs (CSgs) have a composition of 43.68%, 40.51%, and 8.69% of Ca(OH) 2 , CaCO 3 , and CaO, making CSgs a promising material for phosphate removal and recovery. Results demonstrated that CSgs have a high capacity to adsorb P over a wide range of concentrations (25-1000 mg P/L). After P removal, at low P concentration, the adsorbent material is rich in apatite (Ca 5 (PO 4 ) 3 OH), and at high P concentration, brushite (CaHPO 4 •2H 2 O) was the main P compound. The CSg reached a Q max of 224.58 mg P/g, which is higher than other high-performance adsorbents reported in the literature. The phosphate adsorption mechanism was dominated by chemisorption, followed by precipitation according to the pseudo-second-order kinetic model. The solubility of P (74.5 wt%) in formic acid solution and the water-soluble P (24.8 wt%) for CSgs after P adsorption indicated that the final product presents the potential to be used as fertilizer for acid soils. This biomass's processability and high phosphate adsorption performance for P removal make CSgs a potential material for wastewater treatment, and subsequent use of these residues as fertilizer offers a circular economy solution to this problem., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)