Gil, B. (Beatriz)
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- Hepatic and extrahepatic HCV RNA strands in chronic hepatitis C: different patterns of response to interferon treatment(Wiley-Blackwell, 1993) Civeira, M.P. (María Pilar); Riezu-Boj, J.I. (José Ignacio); Qian, C. (Cheng); Gil, B. (Beatriz); Prieto, J. (Jesús)We investigated the presence of positive (genomic) and negative (replicative intermediate) hepatitis C virus RNA strands in liver, peripheral mononuclear cells and serum from patients with chronic hepatitis C using a selective and semiquantitative polymerase chain reaction procedure. Negative and positive hepatitis C virus RNA strands were present in liver, serum and lymphoid cells in all untreated patients and in all those who did not respond to interferon therapy. In the latter group of patients, the titers of RNA strands in the liver and peripheral mononuclear cells at the end of the treatment were similar to those encountered in untreated patients, but the serum titers were about 100 times lower than pretreatment values. In patients who responded to interferon with normalization of serum aminotransferase levels (n = 10), the rate of detection and the titer of the two viral strands in liver, serum and mononuclear cells were markedly decreased at the end of the therapy. In the six responders who did not relapse after interferon withdrawal, both hepatitis C virus RNA strands were absent from the liver, serum and lymphoid cells. By contrast, the positive RNA strand was present in liver cells, mononuclear cells or both at the end of therapy in all patients who experienced posttherapy relapse. In conclusion, our results indicate that interferon can clear hepatitis C virus from hepatic and extrahepatic sites only in responder patients. Disappearance of genomic hepatitis C virus RNA from the liver and from mononuclear cells may predict complete response without posttherapy relapse.
- Design and testing of steel additive-manufactured moment-resistant beam-to-column connection(Elsevier, 2024) Gil, B. (Beatriz); Fábregas, M. (María); Bayo, E. (Eduardo); Goñi, R. (Rufino)The objective of this research is to study an alternative to conventional moment-resisting beam-to-column steel joints through the design of optimised connections made by additive manufacturing using steel. The proposed design is intended to fulfil design criteria such as the following: the connection has to be moment-resistant, and the different structural elements should join as easily as possible, enabling them to be attached and detached and consequently allowing the reuse of steel. The design is achieved by the application of Structural Topological Optimisation tools from the software TOSCA, and it is verified by finite element analysis using ABAQUS. The proposed design reshapes the material and leads to a uniform and optimised distribution of stresses. Blind bolts are no longer necessary and a significant weight reduction is achieved. The final design was printed with S316 stainless steel using the Selective Laser Melting technique, and it was tested under proportional loads until failure. The finite element models were validated with the experimental results. Then, the behaviour of the proposed connection under proportional and non-proportional loads is compared with that of a connection executed by traditional means (welded and bolted plates), as well as a conventional fully welded connection. The proposed connection exhibits a better behaviour than the other connections in terms of stiffness and resistance. In fact, when compared with the conventional welded connection, the values of the stiffness and strength of the optimised design are much higher. In addition, the significantly larger values of the stiffness/weight and strength/weight ratios highlight the efficiency of the proposed design.
- Dimensionado de las escaleras protegidas en caso de incendio: un reto para los métodos prescriptivos (El modelo del CTE)(2018) Gil, B. (Beatriz); Fernández-Vigil, M. (María); Echeverría, J.B. (J. B.)El dimensionado de las escaleras en caso de incendio se encuentra entre las características más importantes del diseño arquitectónico actual. La mayor complejidad de los edificios (usos mixtos, espacios con alta ocupación, personas con discapacidad, edificios en altura, etc.) se suma a nuevos hábitos sociales, y las actividades que se desarrollaban tradicionalmente en las partes bajas de los edificios, tienden a ocupar los pisos más altos. Este artículo muestra que los cálculos prescriptivos para el dimensionado de las escaleras protegidas son incapaces de enfrentarse a este reto por estar basados en modelos simplificados, solamente válidos para edificios y distribuciones convencionales. Analiza el caso del Código Técnico de la Edificación español, mostrando su debilidad, e introduce los conceptos de diseño prestacional necesarios para entender el problema. Concluye que cualquier diseño complejo debe abordarse estudiando el movimiento real de los ocupantes, que puede ser modelizado con la ayuda de herramientas computacionales.
- Major axis steel joint under torsion Stiffness and strength characterization(Elsevier BV, 2019) Bijlaard, F. (Frans); Gil, B. (Beatriz); Bayo, E. (Eduardo); Goñi, R. (Rufino)Torsional effects in joints need to be investigated in order to get a complete model of the joint and also to assess the real boundary conditions for the lateral torsional effects in the beams of structural frames. Phenomena such as: torsion, warping, lateral buckling, etc. are usually analysed assuming simplified boundary conditions, namely pinned or rigid, in frame analysis which can lead to erroneous and non-conservative results. With the aim of knowing the correct boundary conditions and real behaviour of the joints under torsion, an experimental program is carried out consisting of two tests of mayor axis doubled extended bolted end plate joints subjected to torsion about the axis along the length of the beam. These experimental results have allowed the validation of the finite element models carried out using the program Abaqus. Once the models are validated models, a parametric study is performed to assess the stiffness and resistance. This study also verifies that these joints behave in a semi-rigid way when compared with the torsional characteristics of the attached beam. Besides, the beam fails prior to the connection in most cases, and therefore, the joints can be assumed to behave as full-strength. Analytical expressions are proposed and checked with the FEM results proving that the proposed analytical formulae and the proposed mechanical model can predict the stiffness quite accurately, with an average error of 8.5%. Despite these joints can be classified as full-strength under torsion, an assessment of their resistance is done as well.
- Proposal and experimental verification of additive manufactured beam-column connection designed by topological optimization(Wiley, 2023) Gil, B. (Beatriz); Bayo, E. (Eduardo); Goñi, R. (Rufino)The aim of this research is to provide an alternative for the conventional design of beam-to-column connections in building structures. The new design is performed by means of Structural Topological Optimization and executed by means of additive manufacturing with steel. Regarding the methodology, the joint that would be manufactured by conventional methods (i.e. welded and bolted plates) is modelled by means of finite elements in the first place. Its behavior is obtained, as well as the boundary conditions and the loads to be applied to the part that is going to be optimized. Subsequently, a solid part is defined and optimized by means of the optimization module TOSCA. Then, the complete joint is simulated with the optimized connection, and the behavior and the weight of the material used are compared with those of the conventional joint.Some modifications are made to improve some aspects of the design. Afterwards, the optimized joint is printed with steel S316L, the connection is as-sembled with the columns and beams, and it is tested. The experimental results are analyzed to be able to make the necessary adjustments both in the connection and in the design methodology.