Luis Javier Cruz

Silk textile production generates considerable amounts of waste, increasing environmental impact. However, this waste holds significant potential as a sustainable source of regenerated silk fibroin (SF) for biomedical applications. This study investigated the physicochemical properties and cellular compatibility of SF extracted from silk cocoons (SFC) and silk waste (SFW). Both materials demonstrated comparable morphology, thermal stability, and wettability. Structural analysis and amino acid composition revealed that while SFC presented a higher molecular weight, lower polydispersity, and a greater presence of charged amino acid residues (Asp, Arg, Lys, and His), the regeneration process effectively compensates for these variations. Specifically, the transition from random coil to β-sheet during film casting homogenizes the matrix, ensuring that the final biological properties remain comparable. Quantitative metabolic assays confirmed that both SFC and SFW maintain cell viability above 70%, meeting ISO 10993-5 standards for non-cytotoxicity. Furthermore, qualitative cell adhesion studies demonstrated effective fibroblast spreading and attachment to both film surfaces, indicating that the initial molecular variations in the waste source do not compromise the resulting matrix's biological performance. These findings highlight that SFW is a functionally equivalent and sustainable alternative to SFC, suitable for the development of advanced biomaterials.

Sonodynamic therapy (SDT) is an emerging modality for the treatment of malignant tumors that combine low-intensity ultrasound (US) with sonosensitizing agents capable of generating cytotoxic reactive oxygen species (ROS) upon activation. Unlike photodynamic therapy, SDT benefits from the deep tissue penetration of ultrasound, enabling noninvasive treatment of deeply embedded tumors with high spatial precision and minimal systemic toxicity. Despite these advantages, the clinical translation of SDT remains limited due to its low therapeutic efficiency and an incomplete understanding of its underlying mechanisms. This review provides a comprehensive overview of current research trends based on a Scopus literature survey, focusing on the integration of nanotechnology to enhance SDT efficacy. Key mechanisms, therapeutic benefits, limitations, and future challenges are discussed, with an emphasis on the role of nanomaterials in overcoming existing barriers to clinical implementation.

Activated graphene oxide seems to be a promising electrode material for electrochemical double-layer capacitors, also known as supercapacitors or ultracapacitors, and other energy storage purposes. This article summarizes the results of our research about the effect of graphene oxide KOH-catalyzed activation on their specific surface area (SSA) and their capacitance, both strongly related to their electrochemical performance. KOH-catalyzed activation increased the SSA values of the reduced graphene oxide (rGO) from ∼783 m² g⁻¹ to ∼2144 m² g⁻¹; it is important to note that the SSA and oxygen-containing groups are two important factors determining electrochemical performance. Moreover, the highest capacitance value was 50.08 F g⁻¹, using 1.0 M H₂SO₄ as an aqueous electrolyte. Activated graphene-based materials with high SSA support conductive networks decorated with oxygen groups synergistically improve charge storage capability in EDLCs.

Uno de los grandes problemas que se vienen presentando en el mundo, especialmente Colombia, es debido a un acelerado crecimiento poblacional generado por el aumento desbordado de la circulación migrante o movilidad de personas por otras causas o situaciones eventuales de la naturaleza. Estas situaciones sociales vienen afectando sensiblemente el orden urbanístico de las ciudades, particularmente por el confinamiento de la población y el aumento de la contaminación ambiental que aporta este incremento, además de la insalubridad, pobreza, entre otros factores. Para estudiar el crecimiento poblacional en función de variables demográficas y factores ambientales, se construyó una Red Neuronal Artificial para llevar a cabo un análisis de datos que incorporó variables relacionadas tales como CO₂ y otros agentes contaminantes. El propósito fue identificar la influencia de estos agentes tóxicos con el crecimiento de una población. Una vez verificada predicción dinámica mediante la red neuronal, se construyó un modelo matemático para estudiar un caso específico del comportamiento demográfico para una región colombiana por medio de un Diagrama de Forrester bajo condiciones migratorias, natalidad, morbilidad, mortalidad, flujo migratorio (o movilidad de personas debido a otros eventos de la naturaleza) y agentes contaminantes que afectan la salud humana principalmente en enfermedades respiratorias. Los resultados entregaron predicciones y del Diagrama de Forrester constatando relación entre los agentes tóxicos y en los aspectos demográficos.

In the present investigation, the effects of fiber content (20, 30 and 40 wt%) and annealing heat treatment on the thermal properties of the biocomposite material formed by an isotactic polypropylene polymeric matrix (iPP) reinforced with short bamboo fibers (PP/BF) were studied. The coupling agent was iPP with grafting of maleic anhydride molecules (MAPP). The Differential Scanning Calorimetry (DSC) technique was used to determine the melting temperature (Tm), crystallization temperature (Tc), and degree of crystallinity (Xc) of the biocomposites. The melting temperature of pure PP was not significantly affected by the presence of bamboo fibers. However, the degree of crystallinity of PP increased with fiber content. The annealing heat treatment caused an increase in the Tm of pure PP and PP/BF. The composite with 20 wt% fiber content (PP/20F) annealed achieved the highest Xc (37,47 %). The Tc of polypropylene increased with the presence of fibers, and the PP/20F composite reached the highest value (115 degrees C). Also, the study of the Tm of the biocomposites in amorphous state was carried out, and it was observed that the sample with a fiber content of 30 wt% presented an endothermic peak at a temperature of approximately 168 degrees C.

A numerical fragmentation model is proposed to predict the mechanical response of intermingled, unidirectional hybrid composites under tensile loads. The model is based on a previously developed for unidirectional composites considering the critical number of fiber breaks and the correction of the fiber-matrix interfacial strength. Hybrids comprising two reinforcements are considered, and the energetic contribution of reinforcements is evaluated during the damage process. Additionally, the pseudo-ductile strain, yield strength, and the level of degradation of each reinforcement are estimated. The present model is compared with a progressive failure model and micromechanical finite element simulations, obtaining some similarities in the stress-strain behavior. Results show that both low elongation and high elongation fiber sub-composite experience a linear tensile response where fibers remain intact (IF), and fragmentation (FM) where breaking appears. The sliding/separation phenomenon (SS) occurs in one of the sub-composites when crack saturation is obtained, and failure occurs when the other one undergoes the crack saturation. Results also show that the IF, FM, and SS phenomena are conditioned by the fiber mixing ratio, α. The model allows estimating the optimal value of α for which the highest pseudo-ductile strain and hybrid effect are reached.

In this study, short bamboo fibers were obtained using diverse extraction methods. Results obtained by the preliminary fiber traction tests reveal that the fibers obtained using steam explosion equipment possess better mechanical properties than those obtained using other methods. These fibers were used to reinforce a polymeric composite material manufactured using hot compression technique. For this purpose, a 3^k factorial experiment design was applied using fiber and coupling agent concentrations as controllable factor and elasticity modulus as response variable to determine their most appropriate level for developing the best natural composite. From this viewpoint, it was found that the best composite material was obtained by combining 50% w/w fiber and 4% w/w coupling agent, as per the corresponding statistical analysis of variance (ANOVA). For the response variable, the elasticity modulus of the compound increased by 322% (2.91 GPa) in comparison with that of the polymer matrix (0.69 GPa).

In this article, bamboo fibre bundles of "Guadua Angustifolia Kunth" specie were isolated from different locations of the basa zone: upper, middle and lower, through mechanical extraction method. The elastic modulus and the tensile strength were obtained with preliminary tensile tests. Applying the statistical analysis known as ANOVA, it was determined that the mechanical properties are similar in all the extension of the basa zone. From there, fibre bundles were extracted randomly, and a part of the fibre bundles was treated with NaOH (mercerization). Later, tensile tests with different calibration lengths were made for calculate the elastic modulus and the tensile strength of the treated and untreated fibre bundles. Best results belonged to the treated fibre bundles. A good correspondence between the results obtained in this work and the results reported in the literature was concluded.