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A Comparative analysis of a three-phase DAB and an improved LLC bidirectional DC/DC converter for wide input and output voltage range applications
(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-11-04) Escobar Pescina, Luis Arturo; Escobar Valderrama, Gerardo; mtyahinojosa, emipsanchez; Galluzzi Aguilera, Renato; Pool Mazun, Erick I.; Aqui Tapia, Juan; Escuela de Ingeniería y Ciencias; Campus Monterrey; Valdez Reséndiz, Jesús Elias
Bidirectional DC/DC power conversion is a key element in vehicle electrification to provide auxiliary power, typically for battery charging and discharging. There are currently various challenges in single stage isolated bidirectional DC/DC conversion that limit efficiency, especially for wide input and output voltage range conditions.
The Dual Active Bridge (DAB) is a popular topology for this purpose; however, it presents a hard-switched operation under wide voltage and partial load conditions, due to its limited soft-switching region using typical Single-Phase Shift (SPS) modulation.
Resonant converters, on the other hand, possess attractive features such as wide ZVS region, high frequency operation with low switching power losses, high efficiency at a wide voltage range and high power density that can potentially solve the current limitations. The LLC resonant tank is one of the most commonly used configurations, even though it does not have a symmetric voltage gain curve in forward and backward energy flow modes, it can reduce the component count and increase power density compared to a more complex tank network such as the CLLC. However, the conventional LLC topology has limited backward voltage gain that leads to a condition referred to in this thesis as the inequality problem, and for wide input voltage range it is necessary to add a mechanism that is capable of dynamically changing the converter gain to further step up the input voltage and meet the system requirements.
Hence, this thesis presents the following:
1. An improved LLC resonant converter with a center-tapped transformer that can dynamically change the transformer turns-ratio in a tap-changer fashion and considerably increase the input and output voltage range.
2. A comparative analysis between the popular Three-Phase DAB converter and the proposed Center-Tapped LLC (CT-LLC) for a 15-kW application through their simulation models in OrCAD using non-ideal PSpice components.
3. Relevant conclusions derived from the comparative study that highlight the benefits and drawbacks of each topology according to efficiency, performance, reliability, and cost metrics.
Evaluación de la actividad del uniportador de calcio mitocondrial y el manejo del calcio mitocondrial en la función de la célula beta pancreática en un modelo in vitro de lipotoxicidad
(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-11-11) Zamora Benavides, Nora Greys; Alves Figueiredo, Hugo Jorge; emimmayorquin, emipsanchez; Crispín Acuña, José Carlos; García Rovés González, Pablo M.; Vázquez Garza, Eduardo; Escuela de Medicina y Ciencias de la Salud; Campus Monterrey; García Rivas, Gerardo de Jesús
Introducción: El manejo del calcio mitocondrial regulado por el Uniportador de calcio mitocondrial (MCU) ha demostrado desempeñar un rol importante en el proceso de secreción de insulina por la célula β pancreática. Este estudio investiga como en un ambiente pro-diabetogenico inducido por lipotoxicidad la desregulación del manejo de calcio mitocondrial conduce a la perdida de función y muerte de la célula β.
Metodología: Para establecer un modelo in vitro de lipotoxicidad, células RIN5F (línea celular de células β pancreáticas de rata fueron expuestas a diferentes concentraciones de palmitato. La vitalidad y viabilidad fueron analizadas mediante Azul de Alamar y exclusión por azul de tripano, respectivamente. La actividad del MCU y las dinámicas del calcio mitocondrial fueron evaluadas por fluorometría, mientras que las especies reactivas de oxígeno (ERO) fueron medidas usando citometría de flujo. Para analizar la expresión proteica se realizó western blot, y la secreción de insulina mediante ELISA.
Resultados: Después de 24 horas de exposición a 700 µM de palmitato, la viabilidad de las células β disminuyó en un 9%, mientras que la actividad metabólica cambió un 47%. La dinámica del calcio mitocondrial ([Ca²⁺]m) mostró alteraciones, al ser retenido menos del 41% y presentar una velocidad de captación 37% más lenta. Cambio que fue adjudicado a la pérdida de funcionalidad del MCU, debido a la ausencia de diferencias en el nivel de proteína expresada. Además, se documentó un aumento de 1.5 veces de EROs mitocondriales, destacando la ausencia de cambio en el ERO citosólico. Estas modificaciones mitocondriales se acompañaron de un marcado deterioro funcional en las células β, evidenciado por una reducción de 15 veces el contenido total de insulina, aunque la secreción de insulina estimulada por la glucosa no se vio afectada.
Conclusión: Se demostró que la disfunción en el manejo del [Ca²⁺]m, más que cambios en los niveles del MCU, contribuye al deterioro funcional de la célula β pancreática. Estos hallazgos destacan la importancia del MCU como eje regulador de la homeostasis y sugiriéndolo como potencial blanco terapéutico para prolongar la función de la célula β en personas con obesidad.
Engineered mesoporous silica nanoparticles for the co-delivery of quercetin and resveratrol: structural characterization and assessment of antioxidant and anti-inflammatory potential
(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-12-02) Torres Copado, Andrea; Paul, Sujay; mtyahinojosa, emipsanchez; Arvizu Espinosa, María Goretti; Sahare, Padmavati; School of Engineering and Sciences; Campus Monterrey; Estévez González, Miriam Rocío
The global burden of noncommunicable diseases (NCDs) is closely associated with persistent oxidative stress and chronic inflammation. Natural polyphenols such as quercetin and resveratrol possess potent antioxidant and anti-inflammatory activities; however, their therapeutic potential is severely hindered by low aqueous solubility, poor chemical stability, and rapid metabolic degradation. Nanotechnology-based delivery systems offer a promising approach to enhance the bioavailability and functional performance of these bioactive compounds.
Accordingly, this work aimed to co-encapsulate quercetin and resveratrol into mesoporous silica nanoparticles (MSNs), thoroughly characterize the resulting nanocarrier system, and assess its biological properties in vitro. MSNs were synthesized through a modified Stöber method, yielding uniform, spherical, amorphous nanoparticles with an average hydrodynamic diameter of ~126 nm, a high specific surface area (200.3 m²/g), a pore volume of 0.445 cm³/g, and a mean pore diameter of 5.4 nm. Co-loading was achieved using a solvent evaporation method, resulting in high encapsulation efficiencies (79.9% for quercetin and 71.4% for resveratrol). Physicochemical characterization (FTIR, XRD, TGA, DLS, Zeta Potential) confirmed successful drug incorporation, partial amorphization of the polyphenols, enhanced thermal stability, and a sustained release profile extending to 75 hours. The QUE-RES-SiO₂ formulation demonstrated significantly enhanced antioxidant capacity in DPPH, CUPRAC, and ABTS assays, surpassing free resveratrol. Strong anti-inflammatory capacity was also observed in a heat-induced protein denaturation model, with up to 75% inhibition, comparable to free quercetin and the reference drug diclofenac.
In ovarian adenocarcinoma SKOV-3 cells, the formulation exhibited efficient nanoparticle uptake; however, it did not induce cytotoxicity or reactive oxygen species (ROS) production within 24 hours, likely due to slow-release kinetics, intrinsic chemoresistance of the cell line, and low concentrations tested over a limited time. Overall, these results demonstrate that MSNs constitute an effective platform for the co-delivery of quercetin and resveratrol, enhancing their stability and antioxidant and anti-inflammatory potential while overcoming key physicochemical limitations. Although anticancer effects were not observed under the tested conditions, this study establishes a robust foundation for future optimization of release kinetics, dosing strategies, and targeting mechanisms to exploit the therapeutic potential of polyphenols in oxidative stress- and inflammation-driven chronic diseases.