作者: Escobar-García, Diana María ; Pozos-Guillén, Amaury ; Palestino-Escobedo, Alma Gabriela ; Flores, Héctor ; Flores-Rocha, Sofía ; Escobar-Barrios, Vladimir ; Gutiérrez-Sánchez, Mariana

Chitosan-based sponges, incorporating tricalcium phosphate and hydroxyapatite, are extracellular components that represent a novel and impactful advancement in bone regeneration. Their bioactive composition, porous structure, and controlled release capacity are designed to stimulate osteogenesis effectively and could enhance the interrelations of cells in tissues and organs. The objective is to manufacture and characterize chitosan (CHT)-based sponges with different concentrations of nano-hydroxyapatite (nHAP) and tricalcium phosphate (TCP), as well as evaluate their biocompatibility. Composite sponges were manufactured in different concentrations: CHT (S1), 50:30:20 (S2), 60:20:20 (S3), and 70:20:10 (S4) and characterized by FTIR-ATR, TGA, and swelling. For biocompatibility, a cell proliferation assay, hemocompatibility, alizarin red, and its bactericidal effect were performed. Main groups of CHT are detected, and the presence of phosphate groups characteristic of TCP and nHAP was confirmed by FTIR. The nHAP/TCP content was validated using the Thermo Gravimetric Analysis (TGA), and the swelling tests were carried out with simulated body fluid (SBF), which proved stable for S2 and S3. About the biocompatibility tests of the cell proliferation assay, The TCP and nHAP present in the sponges caused a significant increase in cell proliferation (up 50-80 %). In contrast, in the control sample (S1), cell proliferation decreased without becoming cytotoxic (down 25 %). The hemolysis degree was less than 2 % at the times evaluated. Using alizarin red (ARS), it was shown that the different sponges were able to increase calcium deposits by approximately 10-45 % Through the antibiogram, it is assumed that the zone of inhibition occurs about the amount of CHT present in each sponge. Incorporating nHAP/TCP into CHT sponges favors the physical and thermal stability of the material. The sponges were demonstrated to have biocompatible and osteoinductive properties.

2025-04-15·Langmuir

Study of Caesalpinia spinosa Extracts As Green Corrosion Inhibitor for Mild Steel

Article

作者: Vilasó-Cadre, Javier Ernesto ; Reyes-Domínguez, Ivan Alejandro ; Ignat, Nicoleta ; Serrano Aguiar, Carlos Diego ; García Madroñero, Daniela Belén ; Galambos, Ildiko ; Hidalgo, Luis ; Hidalgo, Juan ; Turdean, Graziella Liana ; Brânzanic, Adrian M. V.

The Caesalpinia spinosa plant, known as Tara, was used to prepare a green corrosion inhibitor solution using hot solid-liquid (Soxhlet extraction, Tara-SE) and cold solid-liquid extraction (maceration, Tara-ME) techniques. Their anticorrosive protection ability was tested on mild steel in a 0.1 M HNO₃ solution. The chemical content of the extracts was examined by FTIR and Vis spectrophotometry, and the surface morphology of the mild steel was studied by SEM. The effect of different concentrations of the green inhibitors on the mild steel in acidic solutions was determined by weight loss (WL), potentiodynamic polarization (PP), and electrochemical impedance spectroscopy (EIS) measurements, allowing the estimation of the inhibitor efficiency (IE%). Values of IE ranging from 90.73 to 97.38% for Tara-1000-SE and from 85.3 to 96.05% for Tara-1000-ME were obtained by WL, PP, and EIS experiments. The thermodynamic assessments at different temperatures and concentrations were studied using different adsorption isotherm models (i.e., Langmuir, Freundlich, Temkin, Flory-Huggins, and El-Awady). The best results were confirmed by the best values of the simultaneous R and reduced-Chi-squared statistical parameters. The Gibbs free energy of adsorption (ΔG_ads) value suggests that the inhibitor is physically absorbed on the metal surface. The adsorption mechanism, studied by classical and computational quantum mechanical modeling methods, evidenced strongly developed interactions between gallic acid adsorbate (i.e., the principal component of the Tara extract) and differently cleaved Fe surfaces. Moreover, density functional theory (DFT) based electron localization function (ELF) analysis assessed the nature of these interactions as being characteristic of physisorption processes. The results showed superior inhibition performance of the hot solid-liquid extraction (Soxhlet extract, SE) compared to the cold solid-liquid extraction techniques (maceration, ME), although, according to all research techniques, both extracts demonstrated a satisfactory level of anticorrosive protection for the mild steel exposed to acid conditions.

2025-03-15·Teaching and Learning in Medicine

Bridging Validity Frameworks in Assessment: Beyond Traditional Approaches in Health Professions Education

Review

作者: Leenen, Iwin ; Carrillo-Avalos, Blanca Ariadna ; Sánchez-Mendiola, Melchor ; Trejo-Mejía, Juan Andrés

Construct: High-stakes assessments measure several constructs, such as knowledge, competencies, and skills. In this case, validity evidence for test scores' uses and interpretations is of utmost importance, because of the consequences for everyone involved in their development and implementation. Background: Educational assessment requires an appropriate understanding and use of validity frameworks; however, health professions educators still struggle with the conceptual challenges of validity, and frequently validity analyses have a narrow focus. Important obstacles are the plurality of validity frameworks and the difficulty of grounding these abstract concepts in practice. Approach: We reviewed the validity frameworks literature to identify the main elements of frequently used models (Messick and Kane's) and proposed linking frameworks including Russell's recent overarching proposal. Examples are provided with commonly used assessment instruments in health professions education. Findings: Several elements in these frameworks can be integrated into a common approach, matching and aligning Messick's sources of validity with Kane's four inference types. Conclusions: This proposal to contribute evidence for assessment inferences may provide guidance to understanding the use of validity evidence in applied settings. The evolving field of validity research provides opportunities for its integration and practical use in health professions education.

100 项与 The Autonomous University of San Luis Potosi 相关的药物交易

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100 项与 The Autonomous University of San Luis Potosi 相关的转化医学

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