A Multivariate Study for Determining the Relationship Between Physical Activity, Physical Fitness, and Academic Performance / Estudio multivariado para determinar la relación entre actividad física, condición física y rendimiento académico

The relationship between physical activity, physical fitness, and academic performance has been widely studied internationally. However, reports of this relationship are contradictory, and its impact is still a matter of controversy. For that reason, the current research determined the correlation between these three variables in a group of 56 female and 48 male Colombian students with an average age of 14.08 ± 0.89 years. A quantitative, correlational, and cross-sectional study was carried out. The physical activity was evaluated using PAQ-A questionnaire. For physical fitness, six tests from the Euro fitness battery were used. The academic performance in Spanish, Math, Natural, and Social Sciences were obtained from the grades for the participants at the end of the academic year. Correlations were determined by multivariate multiple linear regression. The obtained results suggest that aerobic endurance test had effect in the studied variables, whereas the correlation of the other tested predictors did not show any meaningful statistical result. In fact, academic performance is not affected by the physical fitness of the students at the time course grades were measured. (AU)

La relación entre la actividad física, la condición física y el rendimiento académico ha sido ampliamente estudiada a nivel internacional. Sin embargo, los reportes de esta relación son contradictorios y su impacto aún es motivo de controversia. Por ello, la presente investigación determinó la correlación entre estas tres variables en un grupo de estudiantes colombianos de los cuales 56 eran de género femenino y 48 masculino, con edad promedio de 14,08 ± 0,89 años. Se realizó un estudio cuantitativo, correlacional y transversal. La actividad física se evaluó mediante el cuestionario PAQ-A. Para la aptitud física, se utilizaron seis pruebas de la batería de test Eurofit. El rendimiento académico en Español, Matemáticas, Ciencias Naturales y Sociales se obtuvo a partir de las notas de los participantes al final del curso académico. Las correlaciones se determinaron mediante una regresión lineal múltiple multivariante. Los resultados obtenidos sugieren que la prueba de resistencia aeróbica tuvo efecto en las variables estudiadas, mientras que la correlación de los otros predictores probados no mostró ningún resultado estadístico significativo. De hecho, el rendimiento académico no es afectado por la condición física de los estudiantes durante el tiempo en el que fueron evaluados. (AU)

Bovine Decellularized Amniotic Membrane: Extracellular Matrix as Scaffold for Mammalian Skin.

Decellularized membranes (DM) were obtained from bovine amniotic membranes (BAM) using four different decellularization protocols, based on physical, chemical, and mechanical treatment. The new material was used as a biological scaffold for in vitro skin cell culture. The DM were characterized using hematoxylin-eosin assay, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR-ATR), and differential scanning calorimetry (DSC). The in vitro cytotoxicity of DM was evaluated using MTT. The efficacy of decellularization process was assessed through DNA quantification and electrophoresis. All the used protocols showed a high effectiveness in terms of elimination of native cells, confirmed by DNA extraction and quantification, electrophoresis, and SEM, although protocol IV removes the cellular contents and preserve the native extracellular matrix (ECM) architecture which it can be considered as the most effective in terms of decellularization. FTIR-ATR and DSC on the other hand, revealed the effects of decellularization on the biochemical composition of the matrices. There was no cytotoxicity and the biological matrices obtained were a source of collagen for recellularization. The matrices of protocols I, II, and III were degraded at day 21 of cell culture, forming a gel. The biocompatibility in vitro was demonstrated; hence these matrices may be deemed as potential scaffold for epithelial tissue regeneration.

(PVA/Chitosan/Fucoidan)-Ampicillin: A Bioartificial Polymeric Material with Combined Properties in Cell Regeneration and Potential Antibacterial Features.

Chitosan, fucoidan, and polyvinyl alcohol are categorized as polymers with biomedical applications. Ampicillin, on the other hand, is considered as an important antibiotic that has shown effectivity in both gram-positive and gram-negative micro-organisms. The aforementioned polymers possess unique properties that are considered desirable for cell regeneration although they exhibit drawbacks that can affect their final application. Therefore, films of these biomaterials were prepared and they were characterized using FTIR, SEM, XRD, degree of swelling and solubility, and MTT assay. The statistical significance of the experiments was determined using a two-way analysis of variance (ANOVA) with p < 0.05. The characterization techniques demonstrated that the obtained material exhibits properties suitable for cell regeneration, and that a higher concentration of natural polymers promotes cells proliferation to a greater extent. The presence of PVA, on the other hand, is responsible for matrix stability and dictates the degree of swelling and solubility. The SEM images demonstrated that neither aggregations nor clusters were formed, which is favorable for the biological properties without detrimental to the morphological and physical features. Cell viability was comparatively similar in samples with and without antibiotic, and the physical and biological properties were not negatively affected. Indeed, the inherent bactericidal effect of chitosan was reinforced by the presence of ampicillin. The new material is an outstanding candidate for cell regeneration as a consequence of the synergic effect that each component provides to the blend.

Synthesis and Characterization of a Bioartificial Polymeric System with Potential Antibacterial Activity: Chitosan-Polyvinyl Alcohol-Ampicillin.

Bio-artificial polymeric systems are a new class of polymeric constituents based on blends of synthetic and natural polymers, designed with the purpose of producing new materials that exhibit enhanced properties with respect to the individual components. In this frame, a combination of polyvinyl alcohol (PVA) and chitosan, blended with a widely used antibiotic, sodium ampicillin, has been developed showing a moderate behavior in terms of antibacterial properties. Thus, aqueous solutions of PVA at 1 wt.% were mixed with acid solutions of chitosan at 1 wt.%, followed by adding ampicillin ranging from 0.3 to 1.0 wt.% related to the total amount of the polymers. The prepared bio-artificial polymeric system was characterized by FTIR, SEM, DSC, contact angle measurements, antibacterial activity against Staphylococcus aureus and Escherichia coli and antibiotic release studies. The statistical significance of the antibacterial activity was determined using a multifactorial analysis of variance with ρ < 0.05 (ANOVA). The characterization techniques did not show alterations in the ampicillin structure and the interactions with polymers were limited to intermolecular forces. Therefore, the antibiotic was efficiently released from the matrix and its antibacterial activity was preserved. The system disclosed moderate antibacterial activity against bacterial strains without adding a high antibiotic concentration. The findings of this study suggest that the system may be effective against healthcare-associated infections, a promising view in the design of novel antimicrobial biomaterials potentially suitable for tissue engineering applications.

Synthesis and Characterization of Poly(Vinyl Alcohol)-Chitosan-Hydroxyapatite Scaffolds: A Promising Alternative for Bone Tissue Regeneration.

Scaffolds can be considered as one of the most promising treatments for bone tissue regeneration. Herein, blends of chitosan, poly(vinyl alcohol), and hydroxyapatite in different ratios were used to synthesize scaffolds via freeze-drying. Mechanical tests, FTIR, swelling and solubility degree, DSC, morphology, and cell viability were used as characterization techniques. Statistical significance of the experiments was determined using a two-way analysis of variance (ANOVA) with p < 0.05. Crosslinked and plasticized scaffolds absorbed five times more water than non-crosslinked and plasticized ones, which is an indicator of better hydrophilic features, as well as adequate resistance to water without detriment of the swelling potential. Indeed, the tested mechanical properties were notably higher for samples which were undergone to crosslinking and plasticized process. The presence of chitosan is determinant in pore formation and distribution which is an imperative for cell communication. Uniform pore size with diameters ranging from 142 to 519 µm were obtained, a range that has been described as optimal for bone tissue regeneration. Moreover, cytotoxicity was considered as negligible in the tested conditions, and viability indicates that the material might have potential as a bone regeneration system.