Browsing by Author "Munoz, L."

Now showing 1 - 6 of 6
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    Automated testing of aluminum castings using classifier fusion strategies
    (AMER SOC NONDESTRUCTIVE TEST, 2005) Mery, D.; Chacon, M.; Gonzalez, L.; Munoz, L.
    Generally, discontinuity detection in automated visual testing consists of two steps: identification of potential discontinuities using image processing techniques and classification of potential discontinuities into discontinuities and regular structures (false alarms) using a pattern recognition methodology. In the second step, since several features cyan be extracted from the potential discontinuities, a feature selection must be performed. In this paper, several known classifiers are studied in automated visual testing: threshold, euclidean, mahalanobis, polynomial, support vector machine and neural network classifiers. First, the performance of the classifiers is assessed individually. Second, the classifiers are combined in order to improve their performance. Seven fusion strategies in the combination were tested: and, or, majority vote, product, sum, maximum and median. The proposed methodology was tested on real data acquired from 50 noisy radiographic images of aluminum wheels, where 23 000 potential discontinuities (with only 60 real discontinuities) were segmented and 405 features were extracted for each potential discontinuity. Using fusion of classifiers, a very good performance was achieved, yielding a sensitivity of 100% and specificity of 99.97%.
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    Effect of a bacterial consortium on passivation property of 2024 aluminum alloy
    (2019) Ortega Ulloa, Daniela Elena; Alvarado, C.; Munoz, L.; Kohler, H.; Pineda Parra, Fabiola Makarena; Paez, M.; Sancy, Mamié; Vejar, N.D.; Blamey, J.M.
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    Improving mechanical properties and antibacterial response of a/b ternary Ti-Ta alloy foams for biomedical uses
    (2023) Aguilar, C.; Martin, F. San; Martinez, C.; Camara, B.; Claverias, F.; Undabarrena, A.; Sancy, M.; Salinas, V.; Munoz, L.
    This study investigates the potential of Ti-Ta-Sn alloys for biomedical applications due to their excellent mechanical properties and biocompatibility, with a particular focus on their use in trabecular bone replacement. This work aims to analyze the influence that of Sn has on the mechanical properties and antibacterial response of a -b ternary Ti-13Ta-xSn (x:3, 6, 9, and 12 at.%) alloy foams. The Ti-based alloys were designed considering three aspects; (i) final microstructure, (ii) alloying element types, and (iii) thermodynamics while using MAAT and ThermoCalc software. The alloys were obtained by mechanical alloying, with used milling times being 30 h for Ti-13Ta-3Sn, 10 h for Ti-13Ta-6Sn, 10 h for Ti-13Ta-9Sn, and 15 h for Ti-13Ta-12Sn. The foams were obtained using NaCl as the space holder (50 v/v% porosity) and consolidated by a hot pressing method at 780 & DEG;C for 30 min, applying a load of 40 MPa. Both the Staphylococcus aureus ATCC 6538 strain and Escherichia coli ATCC 8739 strain were used to evaluate the antibacterial responses of Ti-based alloy foams. The Ti-based alloy foams were composed mostly by a mix of a and b-phases. The metallic foams exhibited relative homogeneous pore distribution with a size between 100 and 450 mm and having an average porosity slightly higher than 50%. The samples showed elastic modulus values be-tween 1 and 2 GPa, compressive yield strengths over 150 MPa, and microhardness over 450 HV. All Ti-based alloy foams showed no antibacterial activity nor bacterial adhesion, indicating that there is bacterial adhesion inhibition.& COPY; 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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    Liver transplantation for hepatocellular carcinoma: evaluation of the alpha-fetoprotein model in a multicenter cohort from Latin America
    (2016) Pinero, F.; Tisi Bana, M.; De Ataide, EC.; Hoyos Duque, S.; Marciano, S.; Varón, A.; Anders, M.; Zerega, A.; Menendez, J.; Soza, Alejandro; Zapata, R.; Munoz, L.; Padilla Machaca, M.; Mccormack, L.; Poniachik, J.; Podesta, LG.; Gadano, A.; Boin, IS.; Duvoux, C.; Silva, M.
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    Mechanobiology of Autophagy: The Unexplored Side of Cancer
    (Frontiers Media S.A., 2021) Hernández-Cáceres, M.P.; Lagos, P.; Morselli, E.; Munoz, L.; Pena, F.; Aceiton, P.; Ravasio, A.; Bertocchi, Cristina; Pradenas, J.M.; Owen, G.I.; Criollo, A.
    Proper execution of cellular function, maintenance of cellular homeostasis and cell survival depend on functional integration of cellular processes and correct orchestration of cellular responses to stresses. Cancer transformation is a common negative consequence of mismanagement of coordinated response by the cell. In this scenario, by maintaining the balance among synthesis, degradation, and recycling of cytosolic components including proteins, lipids, and organelles the process of autophagy plays a central role. Several environmental stresses activate autophagy, among those hypoxia, DNA damage, inflammation, and metabolic challenges such as starvation. In addition to these chemical challenges, there is a requirement for cells to cope with mechanical stresses stemming from their microenvironment. Cells accomplish this task by activating an intrinsic mechanical response mediated by cytoskeleton active processes and through mechanosensitive protein complexes which interface the cells with their mechano-environment. Despite autophagy and cell mechanics being known to play crucial transforming roles during oncogenesis and malignant progression their interplay is largely overlooked. In this review, we highlight the role of physical forces in autophagy regulation and their potential implications in both physiological as well as pathological conditions. By taking a mechanical perspective, we wish to stimulate novel questions to further the investigation of the mechanical requirements of autophagy and appreciate the extent to which mechanical signals affect this process.
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    The effect of Staphylococcus aureus on the electrochemical behavior of porous Ti-6Al-4V alloy
    (2020) Silva Barbieri, Daniela Carolina; Guerra Figueroa, Carolina Andrea; Munoz, H.; Aguilar, C.; Walter, M.; Azocar, M.; Munoz, L.; Gurbuz, E.; Ringuede, A.; Sancy, Mamié; Cassir, M.