Instituto Tecnológico Metropolitano

Dual-fuel combustion is often proposed for diesel engines as a means to partially replace conventional diesel with cleaner and/or more sustainable alternatives, such as those derived from green hydrogen. However, the low reactivity of these fuels (i.e., methane, hydrogen, and ammonia) often leads to prolonged ignition delay (ID) and combustion instability. This challenge could potentially be overcome using nanomaterials, which are additives that could improve reactivity and compensate for autoignition deficiencies. Thus, this study evaluates the effect of carbon nanotubes (CNTs) dispersed in diesel fuel on the autoignition process under dual-fuel operation. CNTs were dispersed at a concentration of 100 mg/L and stabilized with surfactant sodium dodecylbenzene sulfonate (SDBS). The resulting nanofuels were then tested in a constant volume combustion chamber (CVCC) using methane, hydrogen, and ammonia as secondary fuels across various energy substitution ratios and temperatures (535 °C, 590 °C and 650 °C). The results show that the impact of CNTs on ID is negligible, especially at high temperatures. At the lowest tested temperature (535 °C) and 40% methane substitution ratio, only slight reductions in ID were obtained. Nevertheless, this effect is less significant at higher temperatures (590 °C and 650 °C). Regarding pressure gradient, the addition of CNTs and SDBS generally induced a decrease in pressure-peak of up to 15%. This trend is attributed to the trapping of fuel droplets within the CNT structures, which creates a physical barrier that delays vaporization. Results confirm that autoignition, which is expected to be the main phenomenon influenced by CNT addition, is not enhanced.

Skin cancer represents a major public health concern due to high global incidence and mortality rates. Oxidative stress induced by ultraviolet radiation plays a central role in skin carcinogenesis. Natural compounds with chemopreventive properties, such as those derived from Vaccinium meridionale Swartz, have attracted attention for their antioxidant potential. Consequently, this study evaluated the protective effect of V. meridionale against Reactive Oxygen Species (ROS)-induced skin damage in HaCaT keratinocytes. To this end, cells were treated with a water–ethanol extract (0.25–10.0 mg/mL) for 24 h, followed by hydrogen peroxide exposure. Assays assessing cell viability, ROS levels, DNA damage, and cell cycle progression were performed. Additionally, in silico analyses examined interactions between phenolic compounds and proteins involved in oxidative stress regulation, including antioxidant and pro-oxidant targets. Results showed that the extract reduced both ROS accumulation and DNA damage and that cyanidin-3-glucoside may inhibit the pro-oxidant enzyme nitric oxide synthase-2 (NOS2). These findings demonstrate the antioxidant and genoprotective activity of V. meridionale , supporting its potential role in skin cancer prevention.

Triple-negative breast cancer is the subtype with the worst prognosis and has limited treatment options. Bioactive peptides are a promising alternative, having demonstrated antitumor properties with a mechanism of action involving the cell membrane. In this study, we evaluated the Ctn-2 peptide, a fragment of crotalicidin (Ctn), which has shown antitumor activity with highly lytic characteristics but is not selective in non-tumor cells. We evaluated the antitumor activity of the peptide Ctn-2 in triple-negative breast cancer cells and its selectivity over non-tumoral cells. Comparative analyses with LTX-315 and biophysical studies on model membranes indicate that Ctn-2 preferentially interacts with cancer-associated lipids. Functional assays further show that its action involves controlled membrane disruption and associated cellular responses. We also examined the combined effect of Ctn-2 and doxorubicin, finding that Ctn-2 selectively enhanced cytotoxicity in tumor cells and potentiated the activity of conventional chemotherapy. Overall, the results indicate that Ctn-2 is a membrane-active peptide with selective antitumor potential and the ability to improve chemotherapeutic efficacy.

Alopoglossus grandisquamatus is a species only known from its male holotype, collected almost 40 years ago. We report the rediscovery of the Largescale Lizard A. grandisquamatus based on two female individuals from two new localities, extending its known distribution 19 km eastwards and 100 km southwards. Conservation status of Endangered is proposed for A. grandisquamatus. Novel morphological variation is described, including sexual dimorphism in femoral pores. Synonymy of A. grandisquamatus with Alopoglossus eurylepis is discussed, with the dismissal of non-useful diagnostic characters. New characters such as number of femoral pores in males, gular scales arrangement and the number of transversal rows of ventral scales are proposed to diagnose A. grandisquamatus from A. eurylepis. Other characters used by previous authors to differentiate both species are also validated.

La investigación tuvo como propósito evaluar la incidencia de la cultura tributaria en el cumplimiento de las obligaciones fiscales de las pequeñas y medianas empresas del sector de la construcción en la ciudad de Portoviejo. El estudio utilizó un enfoque cuantitativo mediante una investigación exploratoria y descriptiva, aplicando encuestas a una muestra de treinta empresas registradas en el catastro del organismo tributario nacional. Los datos obtenidos evidenciaron un limitado nivel de conocimiento sobre normativas fiscales, mecanismos tributarios y obligaciones formales, así como percepciones negativas respecto al uso y destino de los recursos recaudados. Se identificó que la evasión se relacionó principalmente con la falta de capacitación, la desactualización normativa y la desconfianza hacia la administración pública. Los resultados demostraron que la cultura tributaria de los microempresarios se fundamentó más en el temor a sanciones que en una conciencia fiscal responsable, lo que afecta la sostenibilidad de las empresas y del sistema tributario. Se concluye que el fortalecimiento de la cultura tributaria constituye un eje imprescindible para mejorar el cumplimiento y promover una gestión más eficiente y transparente de los tributos por parte de los contribuyentes.

The development of autonomous and unmanned vessels has become a central focus of maritime research and innovation. The literature includes various studies related to the subsystems and algorithms for the autonomous operation of vessels. However, discussions surrounding the regulatory and normative framework appear to lag behind technological progress. Despite this, the debate cannot be considered null. Some authors have analyzed the operation of autonomous surface vessels (ASVs) and unmanned surface vehicles (USVs) considering the current regulatory framework. There are also reflections on the role of the human component and on the interaction with conventional vessels. On the other hand, the International Maritime Organization (IMO) and different entities have included the topic on their agendas, for which they have activated different mechanisms and scenarios for the development of the debate. Against this backdrop, this paper examines the regulatory and normative framework of the operation of autonomous vessels, trying to identify some of the facets that make up the current debate. The entry into operation of vessels in real-world contexts will be a reality soon and points of convergence between the technological aspect and the social component must emerge. Considering the potential impacts and advantages of integrating new technologies with conventional ones, it is expected that the social debate will develop in such a way that the regulations are timely and appropriate.

Este trabajo presenta el desarrollo de un sistema de adquisición estéreo de bajo costo para la captura tridimensional de plantas de maíz. El sistema está compuesto por una cámara estéreo con sensores IMX219-83 y una Jetson Nano como unidad de procesamiento. Se llevó a cabo un proceso de calibración geométrica mediante un patrón de tablero de ajedrez, con el fin de obtener los parámetros necesarios para la rectificación de las imágenes. A partir de los pares de imágenes rectificadas, se generaron mapas de disparidad que permitieron reconstruir nubes de puntos en 3D. Posteriormente, se aplicó un proceso de segmentación basado en filtrado por color en el espacio HSV y restricción por profundidad, con el objetivo de aislar la región correspondiente a la planta. La herramienta desarrollada permite visualizar, procesar y analizar la estructura espacial de las plantas, contribuyendo a aplicaciones en agricultura de precisión.

The Vehicle Routing Problem (VRP) is a cornerstone of operations research with broad real-world relevance. As variants increase in complexity, researchers increasingly adopt metaheuristics and matheuristics to find high-quality solutions. We focus on set partitioning (SP) and set covering (SC) formulations as enhancement mechanisms in matheuristics for VRPs. These methods exploit previously generated routes by decomposing and recombining solutions, either as a post-optimization step or iteratively. We conducted a meta-analysis of 30 implementations, selected from 54 eligible studies identified via systematic review of Web of Science and Scopus, complemented by backward snowballing. Using a random-effects model, we quantified the effect of SP/SC enhancements on solution quality. On average, SP/SC improved solutions by 0.51% (95% CI: 0.41%–0.61%). Although the numerical gains are modest, they are consistent and significant, highlighting the practical value of these classical formulations in hybrid heuristic frameworks. • Set Partitioning/Set covering enhances Vehicle Routing Problems heuristics. • Meta-analysis of 30 implementations quantifies impact on solutions. • Methods effective across diverse Vehicle Routing Problems variants. • Improves solutions by average 0.51% (95% interval: 0.41%–0.61%).