idUS. Depósito de Investigación Universidad de Sevilla
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In vitro evaluation of the toxicity mechanisms of two functionalized reduced graphene oxide derivatives
No full textDodecyl amine functionalized reduced graphene oxide (DA-rGO) and [2-(methacryloyloxy) ethyl] trimethylammonium chloride functionalized rGO (MTAC-rGO) have been developed and characterised for their further use in the food packaging industry as food contact materials. But before their application, an authorization procedure is required in which their safety plays a key role. Therefore, the aim of this work was to evaluate their toxicity with focus on two different toxicity mechanisms: genotoxicity and immunotoxicity. Following the recommendations of the European Food Safety Authority, the mutagenicity and genotoxicity were evaluated by the mouse lymphoma assay and the micronucleus assay, respectively, in L5178Y TK cells. Both assays did not show any effect at the tested concentrations (up to 200 μg/mL). The potential immunotoxicity was evaluated on two human cell lines: THP-1 (monocytes) and Jurkat (lymphocytes). The results showed that the highest cytotoxicity was induced by MTAC-rGO in Jurkat cells. The two functionalized rGO compounds did not significantly affect the differentiation process of monocytes into macrophages. In general, both compounds altered the expression of different cytokines, with the most prominent changes observed with MTAC-rGO in THP-1 cells. Moreover, MTAC-rGO induced the most evident differences in markers of cell death mechanisms. Also, for this graphene derivative, increased levels of IL-1β and TNF-α in THP-1 cell supernatants were observed by ELISA. In conclusion, a case-by-case evaluation is necessary as both functionalized rGO compounds exhibit distinct toxicity profiles that warrant further investigation before their application in the food industry
Product innovation, new product commercialisation and competitive advantage: the role of process innovation
No full textTechnological innovation is essential for achieving sustainable competitiveness and superior growth, particularly in today’s turbulent business environment. However, it remains unclear how the interconnected impacts of technological innovation efforts contribute to a firm’s higher economic performance compared to its industry counterparts. This paper fills this research gap. We use the System Generalised Method of Moments technique to analyse a sample of 1780 Spanish manufacturing firms. The findings indicate that merely introducing product innovations does not necessarily lead to competitive advantage; instead, it is a firm’s ability to successfully commercialise its new product offerings. Additionally, the analysis reveals the importance of process innovation in enhancing the commercialisation efforts of firms to achieve superior performance. Moreover, the findings of this study have practical implications, especially for managers and practitioners who are pursuing growth strategies through investments in technological innovations
La evolución de un motivo en la lírica andalusí: el caballo árabe
No full textEn este artículo analizamos el motivo lírico del caballo en la poesía andalusí, uno de los más prolíficos de esta civilización. Desde la tradición preislámica hasta el apogeo de la cultura arábigo-islámica en Oriente, permanece en al-Andalus este motivo, aunque adaptado al entorno específico de la península Ibérica
Exploring Vein Biometrics on Ordinary Smartphones Using CNNs and Transfer Learning with Open and Closed Sets
No full textThis paper explores the feasibility of using vein recognition for biometric authentication on ordinary smartphones. A new dataset, USE-V2, consisting of 6600 vein images from dorsal hands and wrists, was collected under three different ambient conditions. Instead of designing a Convolutional Neural Network (CNN) from scratch, we used transfer learning with a pre-trained FaceNet model for extracting vein features and evaluated its performance in both open-set and closed-set scenarios with USE-V2 dataset. The recognition performance is acceptable when an open-set scenario with selection of ambient condition is considered (average EER of 5.18% for dorsal hands and 5.88% for wrists), and quite competitive for a closed-set scenario (average EER of 0.6% for dorsal hands and 0.75% for wrists). This approach paves the way for an efficient multimodal system integrating facial and vein recognition on smartphones, sharing most of the CNN layers.Ministerio de Ciencia, Innovación y Universidades CPP2022-009796, PDC2023-145873-I00, PID2020- 119397RB-I0
Numerical and experimental analysis of ultra-thin plies in carbon/epoxy cross-ply laminates subjected to bending after tensile cyclic loading
No full textAs a result of a fatigue testing campaign in cross-ply laminates with different thicknesses in the 90° ply block (conventional and ultra-thin), different cracking patterns were observed. While laminates with conventional 90° ply thickness show a damage pattern with transverse cracks in the 90° ply block and delaminations along the 0°/90° interface, laminates with ultra-thin plies show paths of debonds inside the ultra-thin 90° ply block both transverse and longitudinal to the loading direction. In order to see the influence that these different fatigue damage patterns could have on the mechanical behaviour of the laminates, static bending tests have been carried out after cyclic loading, and apparent flexural stiffness loss (concerning the pristine state) was measured. Numerical simulations of the bending test, including the cyclic damage pattern (and detailed non-linear frictionless contact conditions) were also carried out for a deeper understanding of the experimental evidence. Although the morphology of the fatigue damages encountered is different for the two studied 90° ply block thicknesses, their flexural behaviours are quite similar, in terms of apparent flexural stiffness loss, for both cross-ply laminates, independently of its 90° ply block thickness.Universidad de Sevilla VIPPIT-2018-II.2Consejería de Economía y Conocimiento, Junta de Andalucía P18-FR-3360Ministerio de Ciencia, Innovación y Universidades PID2021-126279OB-I0
Averaging material tensors of any rank in textured polycrystalline materials: Extending the scope beyond crystallographic proper point groups
No full textIn many modern micromechanical applications, there is usually a need to perform the orientational averaging of certain material tensors weighted by an orientation distribution function (ODF). The computation of these averages is seen to be very simplified by means of the so-called generalized spherical harmonic method (GSHM), which is based on the classical assumption that the ODFs are defined in the rotation group
. A priori, this makes the averaging strictly applicable only to polycrystals with crystallite symmetry defined by one of the 11 proper point groups. Despite the interest in the study of materials belonging to any of the other 21 point groups, few studies have properly considered such cases. This is crucial for physical properties represented by odd-order tensors such as the third-order linear piezoelectric tensor. The goal of this work is to extend the applicability of the GSHM to crystallites with symmetry that belongs to the orthogonal group
. Thus, a simple formula is provided for the averaging of material tensors of any rank in textured polycrystals containing crystallites with symmetry defined by any of the 32 crystallographic point groups. Our work presents a simple yet rigorous method for indirect averaging on the orthogonal group, using averaging on
. We demonstrate the full equivalence between our proposed method and averaging properly on
through a detailed proof provided in this paper. This proof represents a significant contribution to the field, providing a practical and reliable approach for researchers working with crystalline materials. The results reported here confirm the validity of closed-form expressions previously derived by the authors for piezoelectric materials.Consejería de Economía, Conocimiento, Empresas y Universidad, Junta de Andalucía P18-RT-312
Conectando la academia y la industria: OPTOEL 2023
No full textEste volumen compila el conjunto de actividades llevadas a cabo durante la celebración de la XIII Reunión del Comité de Optoelectrónica, perteneciente a la Sociedad Española de Óptica SEDOPTICA y celebrada en la Escuela Técnica Superior de Ingeniería de la Universidad de Sevilla los días 14, 15 y 16 de junio de 2023. Bajo el lema "Conectando la academia y la industria" se exploraron durante esta cita los últimos avances en el campo de la fotónica y la optoelectrónica realizados en España y se intercambiaron ideas en torno a las novedades surgidas en este ámbito de investigación. El libro contiene el programa completo de la reunión, en el que se describen las actividades llevadas a cabo, la relación de empresas participantes con sus espacios de exposición y charlas técnicas, las actividades del Foro de Innovación y Foro de Empleo, las comunicaciones científico-técnicas presentadas por los asistentes, así como el fallo de los premios a estudiantes en sus diversas categorías
El "nocturno" en la poesía mexicana moderna
No full textEl propósito de esta investigación es examinar el surgimiento y la evolución en México del subgénero poético moderno conocido como “nocturno”. Este estudio, que se extiende desde el porfiriato hasta finales del siglo XX, se inicia con la exploración de las manifestaciones culturales y artísticas que hacen referencia a la noche, rastreando sus raíces simbólicas desde las primeras escrituras que han configurado las bases de la literatura occidental hasta Sor Juana Inés de la Cruz. A lo largo de los siglos, la noche se ha configurado como tiempo mítico que alberga tanto connotaciones positivas como negativas, un fenómeno ampliamente representado a partir de variados motivos o tópicos como lo sublime, lo prohibido o lo marginal. Desde el Romanticismo, atravesado por la secularización moderna, el sujeto poético se ha refugiado en la nocturnidad para buscar su salvación en un espacio que paradójicamente también remite al horror, expresando sus afectados pesares con una acentuada subjetividad. Los románticos mexicanos, marcados por la Independencia, reflejaron estas circunstancias en la naturaleza que les rodeaba y hasta en el propio proceso creador de la poesía, principalmente entre los integrantes de la Academia de Letrán. Un segundo romanticismo atenuó las formas hiperbólicas anteriores y asentó un lenguaje más cotidiano como se puede apreciar en Manuel M. Flores, aunque todavía continuaran motivos como el suicidio en “Nocturno a Rosario” de Manuel Acuña. Los siguientes esfuerzos del simbolismo finisecular, que prefiguraron una poesía autónoma basada en la relación con otras artes y las propias conexiones internas del texto, condujeron a consolidar el subgénero del nocturno en la literatura en español. En el período modernista se ha destacado la contribución nocturna de José Juan Tablada, primero con una vertiente decadente y transgresora y luego con formas japonistas y simultaneístas que marcan la transición hacia la vanguardia. Esta continuó la exploración de la nocturnidad al celebrar el progreso y adoptar una actitud revolucionaria a través del estridentismo. Una actitud contraria tomó el grupo Contemporáneos en el escenario del debate sobre lo nacional, cuyas obras de los años treinta comenzaron a reflejar un descontento mediante incertidumbres o imágenes oníricas. En este contexto Xavier Villaurrutia se convirtió en un profundo cultivador del nocturno, así como un explorador de los secretos de la muerte hasta la liberación de sus represiones a través de su faceta homoerótica. Otros poetas de la época como Elías Nandino enriquecieron esta tradición de la noche, pero será Octavio Paz quien la amplía y la conecta con el surrealismo, sondeando lo invisible y misterioso. La obra del Nobel resulta en una suerte de culminación que dialoga con las raíces históricas y culturales, así como con las de la propia poesía. En resumen, esta investigación traza un viaje a lo largo de la poesía mexicana a través del nocturno, un subgénero que contiene aquellos valores opuestos o complementarios a los asociados desde tiempos remotos al día. Como consecuencia, este estudio histórico-crítico intenta revisar esta tradición desde una nueva perspectiva y se focaliza en el papel fundamental que ha tenido la nocturnidad para la conformación de los textos en las diferentes evoluciones de la modernidad.The purpose of this research is to examine the emergence and evolution of the modern poetic subgenre known as the “nocturne” in Mexico. This study, spanning from the Porfiriato era to the end of the twentieth century, opens with an exploration of cultural and artistic expressions referencing the night. It traces its symbolic origins from the earliest literary works that have laid the groundwork for Western literature, including those of Sor Juana Inés de la Cruz. Over the centuries, night has been conceived as a mythical time that encompasses both positive and negative connotations: a phenomenon frequently depicted through various motifs such as the sublime, the forbidden, or the marginal. Since the Romantic era, marked by modern secularization, poets have sought refuge in the night to seek solace in a space paradoxically associated with horror. They express their deep sorrows with heightened subjectivity. The Mexican Romantics, deeply influenced by the Independence movement, mirrored these circumstances in the surrounding natural world and even within the creative process of poetry, particularly among members of the Academy of Letran. A subsequent wave of Romanticism toned down the previous hyperbolic forms, adopting a more everyday language, exemplified by Manuel M. Flores, although themes like suicide persisted in Manuel Acuña's “Nocturno a Rosario”. The subsequent endeavors of fin-de-siècle symbolism, which foreshadowed an autonomous poetry characterized by its interaction with other art forms and internal textual connections, solidified the nocturne subgenre within Spanish-language literature. During the modernismo, José Juan Tablada’s contributions to the nocturne genre were noteworthy. Initially, Tablada embraced a decadent and transgressive aspect, later transitioning to Japanese and simultaneist forms that marked the shift towards the avant-garde. The latter continued to explore nocturnality, celebrating progress and adopting a revolutionary stance through Stridentism. In contrast, the Contemporáneos group, amidst the national debate of the 1930s, expressed discontent through uncertainties and dreamlike imagery in their works. In this context, Xavier Villaurrutia emerged as a prolific cultivator of the nocturne, delving into the secrets of death, and ultimately liberating his repressed homoerotic facet. Poets like Elías Nandino enriched this tradition of nocturnes, but it was Octavio Paz who expanded and connected it with surrealism, delving into the invisible and the mysterious. Paz's work can be seen as a culmination that engages with historical, cultural, and poetic roots.
In summary, this research traverses Mexican poetry through the lens of the nocturne, a subgenre that focuses on values contrasting or complementing those traditionally associated with daylight. As a consequence, this historical-critical study attempts to review this tradition from a new perspective and focuses on the fundamental role that nocturnality has played in the shaping of texts in the different evolutions of modernity
Vibration based single-objective finite element model updating using cooperative game theory approach
No full textThis paper introduces a novel approach that focuses on application of cooperative game theory model for automated finite element model updating. The approach involves transforming the conventional single-objective optimization finite element model updating problem into a game theory problem. Among the different alternatives, a cooperative game model is considered to solve the transformed updating problem. This new approach overcomes the limitations of the conventional single-objective optimization formulation, which include challenges related to selecting appropriate weighting factor of residuals and analysing their influence on optimization results. To demonstrate the effectiveness of the proposed approach, an ultralight fibre reinforced polymer footbridge is considered. The numerical model of the footbridge is updated using the experimentally determined inherent properties (natural frequencies and mode shapes) using the proposed approach. A comparison with the conventional sensitivity-based weighted single objective method reveals that the inclusion of the weighting factor in the optimization process under the cooperative game model method allows for more efficient solution of the single-objective updating optimization problem, while maintaining accuracy and quality in the updated model