Repositorio Nacional

Metabolic syndrome (MS) has been associated with testicular damage. Nonalcoholic fatty liver disease (NAFLD) is a multisystemic disease that affects different organs, but its effect on the testes is unknown. A study analyzing germ cell involvement on BALB/c mice was carried out. A parallel comparative study was conducted that investigated alterations in the germinal epithelium of male humans that died from an unrelated acute event. The complete medical histories and histologic samples of the thoracic aorta, liver tissue, and testicular tissue from the deceased subjects were collected. The degree of germinal epithelial loss (DGEL) was evaluated and the clinical and histologic data were compared between individuals with and without NAFLD. The only metabolic or morphologic variable that caused a significant difference in the DGEL, in both the animal model and humans, was the presence of liver steatosis. The percentage of steatosis was also correlated with the percentage of the DGEL. In humans, steatosis (greater than 20%) increased the risk 12-fold for presenting with a severe DGEL (OR: 12.5; 95% CI [1.2, 128.9]; p = .03). There was no association with age above 50 years or MS components. Steatosis grade was also correlated with atherosclerosis grade. NAFLD was a strongly associated factor implicated in severe DGEL, as well as the testis was identified as a probable target organ for damage caused by the disease. his finding could result in the search for new approach strategies in the management of men with fertility problems. Further studies are required to confirm these results.

MEDICINA Y CIENCIAS DE LA SALUD Germ cells Atherosclerosis Testis Metabolic syndrome

Product development for Eastern Africa: EA-PP1

EA-PP2

Berhanu Tadesse Ertiro Aparna Das Yoseph Beyene Dan Makumbi Manje Gowda Suresh L.M. Anani Bruce Walter Chivasa Vijay Chaikam Juan Burgueño Prasanna Boddupalli (2023, [Objeto de congreso])

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA PRODUCT DEVELOPMENT TESTING DATA MAIZE

GENERATION OF LG VECTOR MODES WITH ULTRAHIGH STABILITY BASED ON COMPLEX AMPLITUDE MODULATION IN AN ON-AXIS CONFIGURATION

Gloria Elizabth Rodríguez García (2023, [Tesis de maestría])

"This thesis presents a novel technique for generating vector beams using complex amplitude modulation (CAM) in an on-axis configuration. The holograms used to generate the beams were created using the Mathlab software and displayed on a reflective spatial light modulator (SLM). The main goal of this research was to address both the purity and stability of the beams during generation and propagation, introducing a quantitative approach to assess their stability. As a proof-of-concept, Laguerre-Gaussian vector beams have been generated and characterized using Stokes polarimetry with the proposed experimental set up."

Structured light Laguerre-Gauss vector beams Stokes polarimetry Beam generation Spatial light modulators CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ÓPTICA OPTICA FÍSICA OPTICA FÍSICA

Metodología predictiva para el análisis de asiento trasero en pruebas de anclaje de cinturón de seguridad

Predictive methodology for rear seat analysis in seat belt anchorage testings

José Guadalupe Velasco Ortega GIOVANNI VIDAL FLORES (2023, [Artículo])

Se presenta una metodología a seguir para el análisis de un asiento trasero durante la prueba de anclaje del cinturón de seguridad, establecida en la norma FMVSS 210 por sus siglas en ingles Federal Motor Vehicle Safety Standards. Es importante destacar que el cinturón de seguridad reduce el riesgo de lesiones, y en caso de colisión, el cinturón ayuda a distribuir la fuerza del impacto en una superficie más grande es decir la estructura metálica del asiento, lo que se busca es minimizar el riesgo de lesiones graves. La metodología propuesta tiene el fin de predecir el desempeño como función del desplazamiento de la estructura metálica mediante el uso del elemento finito (FEM). En esta metodología, se analiza la menor cantidad de elementos que compone la estructura del asiento con el propósito de reducir el tiempo del análisis, considerando solo los elementos y componentes que tienen mayor efecto con el desempeño del cinturón de seguridad, generando el análisis más rápido y eficiente. Al contrastar los resultados obtenidos a través del análisis mediante elemento finito con las pruebas reales se determinó que el método FEM es eficaz para predecir los puntos débiles de la estructura metálica que influyen en el desplazamiento y/o deformación del asiento durante la prueba.

A methodology is presented for analysis of a rear seat during the Safety Belt Anchorage test established in FMVSS 210 [1], which stands for Federal Motor Vehicle Safety Standards. It is important to note that the safety belt reduces the risk of injury, and in the event of a collision, the belt helps distribute the force of the impact over a larger surface area, namely the metal structure of the seat. The goal is to minimize the risk of serious injuries. The goal of proposed methodology is to predict the performance as a function of displacement of the metal structure by using Finite Element Method (FEM). In this methodology, the minimum number of elements that make up the seat structure is analyzed in order to reduce analysis time, considering only the elements that play and have effect on the performance of the safety belt, thus generating a faster and more efficient analysis. By comparing the results obtained through Finite Element Method with the actual test, it was determined that the FEM method is effective in predicting the weak points of the metal structure that influence the displacement and/or deformation of the seat during the test.

FVMSS 210 Método de elemento finito Asiento trasero Prueba de anclaje Cinturón de seguridad Finite element method Rear seat Anchorage test Seat belt INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS OTRAS ESPECIALIDADES TECNOLÓGICAS OTRAS OTRAS

REMATTOOL-R: a smart tool for identifying superior maize genotypes from multi-environment yield trials

Lewis Machida Dan Makumbi (2023, [Artículo])

Maize Variety Testing Multienvironment Trial Analysis Relative Maturity REMATTOOL-R Superior Varieties Identification CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA MAIZE VARIETIES MATURITY IDENTIFICATION YIELDS

Fabrication of PVDF/PMMA Polymer for Sustainable Energy Harvesting .

JOSE RAYMUNDO LEPPE NEREY FERNANDO ZENAIDO SIERRA ESPINOSA MIGUEL ANGEL BASURTO PENSADO JOSE ALFREDO RODRIGUEZ RAMIREZ (2023, [Artículo])

The synthesis of blends that combine properties of two or more polymeric materials is increasingly investigated due to the versatility of the synthesis and its growing potential for many applications, including sustainability. Their characteristics are defined mainly by the synthesis conditions. Therefore, this paper details the synthesis process of easy-to-handle films using mixing method. The procedures and drawbacks found during the preparation of composite films are described. Polymeric compounds formed by the mixture of polyvinylidene fluoride (PVDF) and polymethyl methacrylate (PMMA) are addressed, varying the concentration, and evaluating their impact on the piezoelectric capacity. Films were formed through the spin-coating technique and characterized by optical and holographic microscopes. The results showed that composites with a concentration of 50 wt.% or larger of PVDF in the blend acquire a morphology with a granular appearance, however at lower concentrations they present a homogeneous morphology similar to that of PMMA. A homogeneous distribution of PVDF in the PMMA stands out. However, excessive contents of PMMA are associated to peaks and non-uniformities detected like multicolored regions by digital holography. Controlled strength-strain laboratory tests allowed to evaluate the film blends performance. The results indicate noticeable improvements in voltage output for a composition 70wt% PVDF and 30 wt% PMMA.

INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS Polymer blends, Power generation, Energy harvesting, Piezoelectricity,

Diseño de arreglos de antenas para entornos de 5G utilizando técnicas de simplificación en la red de alimentación

Design of antenna arrays for 5G environments using simplification techniques in the feeding network

ELIZVAN JUAREZ PACHECO (2023, [Tesis de doctorado])

En los últimos años, las redes de comunicaciones inalámbricas de quinta generación (5G) han tomado gran relevancia debido al crecimiento del número de usuarios móviles que se conectan a estas redes inalámbricas. Estas redes utilizan arreglos de antenas para generar haces de radiación directivos que pueden escanearse en una o múltiples direcciones en el espacio mediante el control de una red de alimentación. En una red de alimentación convencional cada elemento de antena se alimenta con un dispositivo amplificador y desfasador, lo que resulta en sistemas costosos y complejos de implementar. Por lo tanto, esta tesis de investigación propone nuevas técnicas de diseño que simplifican la red de alimentación al reducir el número de puertos de entrada y dispositivos desfasadores necesarios en el sistema de antenas. Las configuraciones propuestas consideran como requisitos de diseño el nivel de lóbulo lateral (SLL por sus siglas en inglés), rango de escaneo del haz principal y ancho de banda de operación adecuados para sistemas de 5G. Así, se introduce la técnica de bloques CORPS (Estructuras Periódicas de Radiación Coherente, en inglés) como una solución para simplificar la red de alimentación en arreglos lineales y planares. Esta técnica aprovecha la propiedad de interpolación de fase de las redes CORPS de una capa para generar los valores cofasales ideales necesarios para escanear el haz principal. Además, la aplicación de una excitación de amplitud de coseno alzado genera un haz de radiación con bajo SLL. Adicionalmente, se aplica la técnica de bloques CORPS en configuraciones con subarreglos para mejorar la reducción de desfasadores en comparación con la implementación individual de cada tecnología. Los resultados obtenidos mediante simulación electromagnética y mediciones experimentales validan los diferentes diseños propuestos. Todo esto contribuye al estado del arte al presentar diferentes diseños de arreglos de antenas que simplifican la red de alimentación manteniendo buenas características en el patrón de radiación en comparación con diseños tradicionales.

In recent years, fifth-generation wireless networks (5G) have become very relevant due to the exponential growth in the number of mobile users connecting to wireless networks. These networks employ antenna arrays to generate directional radiation beams that can be scanned in one or multiple directions in space by controlling a feeding network. In a conventional feeding network, each antenna element is fed with an amplifier and phase shifter device, which results in expensive and complex systems to implement. Therefore, this thesis proposes novel design techniques that simplify the feeding network by reducing the number of input ports and phase shifter devices required in the antenna system. The proposed configurations take into account requirements such as side lobe level (SLL), scanning range, and bandwidth appropriate for 5G systems. Thus, the CORPS (Coherent Radiation Periodic Structures) blocks technique is introduced as a solution to simplify the feeding network in linear and planar phased arrays. This technique takes advantage of the phase interpolation property of single-layer CORPS to generate the ideal cophasal values necessary for the main beam scanning. Furthermore, the application of a raised-cosine amplitude distribution generates a radiation beam with low SLL. Additionally, the CORPS blocks technique is applied in subarrays configurations to improve the phase shifters reduction compared to the individual implementation of each technology. The results obtained by electromagnetic simulation and experimental measurements validate the different proposed designs. This contributes to the state of the art by different designs of antenna arrays that simplify the feeding network while maintaining good radiation pattern characteristics when compared to traditional designs.

Arreglo de antenas, Red de alimentación, Quinta generación, Arreglo lineal, Arreglo planar Antenna array, Feeding network, Fifth Generation, Linear array, Planar array INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE LAS TELECOMUNICACIONES ANTENAS ANTENAS