259 research outputs found

    The histone deacetylase inhibitor valproic acid attenuates phospholipase Cγ2 and IgE-mediated mast cell activation.

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    Mast cell activation through the high-affinity IgE receptor (FcεRI) plays a central role in allergic reactions. FcεRI-mediated activation triggers multiple signaling pathways leading to degranulation and synthesis of different inflammatory mediators. IgE-mediated mast cell activation can be modulated by different molecules, including several drugs. Herein, we investigated the immunomodulatory activity of the histone deacetylase inhibitor valproic acid (VPA) on IgE-mediated mast cell activation. To this end, bone marrow-derived mast cells (BMMC) were sensitized with IgE and treated with VPA followed by FcεRI cross-linking. The results indicated that VPA reduced mast cell IgE-dependent degranulation and cytokine release. VPA also induced a significant reduction in the cell surface expression of FcεRI and CD117, but not other mast cell surface molecules. Interestingly, VPA treatment inhibited the phosphorylation of PLCγ2, a key signaling molecule involved in IgE-mediated degranulation and cytokine secretion. However, VPA did not affect the phosphorylation of other key components of the FcεRI signaling pathway, such as Syk, Akt, ERK1/2, or p38. Altogether, our data demonstrate that VPA affects PLCγ2 phosphorylation, which in turn decreases IgE-mediated mast cell activation. These results suggest that VPA might be a key modulator of allergic reactions and might be a promising therapeutic candidate

    Using the second-order information for reconfigurability analysis and design in the fault tolerant framework

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    The control reconfigurability measure defines the capability of a control system to allow recovery of performance when faults occur; therefore, it has been intended to be a tool for designing and synthesizing approaches in the fault tolerant control context. Reconfigurability depends on the controllability gramian, also known as the second-order information (SOI) in a broad sense. This paper proposes the assignation, by feedback, of the deterministic SOI in order to set the control reconfigurability of a given linear system. The theory concerned with this assignation is reviewed, then constructive theorems are given for finding constant feedback gains that approximate a required control reconfigurability for ease implementation. Also an unification of the reconfigurability measures proposed in the fault tolerance literature is given. Once the SOI is assigned by feedback, it can be computed online by using an identification method, which uses process input/output data. Results from simulation of the three tanks hydraulic benchmark, show that this approach can provide information about the system performance for fault tolerant purposes, thus online control reconfigurability computation and fault accommodation are considered. The approach presented in the paper gives an alternative for supervision taking into account the reconfigurability assigned by design

    Fault detection in unmanned aerial vehicles via orientation signals and machine learning

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    [EN] This work proposes an actuator fault detection and isolation scheme for a quadrotor unmanned aerial vehicle (UAV) under a data-driven approach using machine learning techniques. In this approach, an implicit model of the system is built through the information provided by the onboard sensors of the UAV. First, using a tailored flying platform, vibrations corresponding to the orientation, angular position and linear acceleration were captured with the UAV flying in hover mode under nominal conditions. This data is processed by Principal Component Analysis (PCA) for feature extraction. Subsequently, faults in the actuators are induced through a cut in each of the UAV propellers which generate a reduction in the thrust of the rotors. These data are also projected into the PCA subspace and compared to the nominal data. Hotelling’s T 2 statistic is used to discern between nominal data and data when the vehicle exhibits an actuator fault. Finally, the developed algorithms were complemented with k-nearest neighbors (k-NN) and support vector machine (SVM) classification algorithms. The results show a correct classification rate of 89.6 % (k-NN) and 92.4 % (SVM) respectively for 423 validation datasets.[ES] Este trabajo propone un esquema de detección y localización de fallas en los actuadores de un vehículo aéreo no tripulado (VANT) del tipo cuadrirrotor. Para ello, se considera un enfoque basado en datos haciendo uso de técnicas de aprendizaje de máquina. En este enfoque se construye un modelo implícito del sistema a través de la información proporcionada por los sensores del VANT. Primero, a través de un plataforma de vuelo de tipo giroscópica, se captan las vibraciones correspondientes a la orientación, posición angular y aceleración lineal cuando el vehículo se encuentra en vuelo estacionario en condiciones nominales. Estos datos se procesan mediante Análisis en Componentes Principales (PCA) para la extracción de características. Posteriormente, se induce una falla a los actuadores a través de un recorte en cada una de las hélices del VANT que ocasionan una reducción del empuje generado por los rotores. Estos datos se proyectan también al subespacio de componentes principales y se comparan con los datos nominales. Para discernir entre los datos nominales y los datos cuando el vehículo presenta falla, se emplea el estadístico T2 de Hotelling. Finalmente, el desarrollo se complementa con los algoritmos de clasificación de k-vecinos más cercanos (k-NN) y de máquina de vectores de soporte (SVM). Los resultados muestran una tasa de clasificación correcta del 89.6 % (k-NN) y 92.4 %(SVM) respectivamente para 423 conjuntos de datos de validación.López-Estrada, FR.; Méndez-López, A.; Santos-Ruiz, I.; Valencia-Palomo, G.; Escobar-Gómez, E. (2021). Detección de fallas en vehículos aéreos no tripulados mediante señales de orientación y técnicas de aprendizaje de máquina. Revista Iberoamericana de Automática e Informática industrial. 18(3):254-264. https://doi.org/10.4995/riai.2020.14031OJS254264183Alos, A., Dahrouj, Z., 2020. Detecting contextual faults in unmanned aerial vehicles using dynamic linear regression and k-nearest neighbour classifier. Gyroscopy and Navigation 11, 94-104. https://doi.org/10.1134/S2075108720010046Baskaya, E., Bronz, M., Delahaye, D., 2017. Fault detection & diagnosis for small uavs via machine learning, in: Digital Avionics Systems Conference (DASC), 2017 IEEE/AIAA 36th, IEEE. pp. 1-6. https://doi.org/10.1109/DASC.2017.8102037Benini, A., Ferracuti, F., Monteriu, A., Radensleben, S., 2019. Fault detection of a VTOL UAV using acceleration measurements, in: 2019 18th European Control Conference (ECC), IEEE. pp. 3990-3995. https://doi.org/10.23919/ECC.2019.8796198Freeman, P., Pandita, R., Srivastava, N., Balas, G.J., 2013. Model-based and data-driven fault detection performance for a small UAV. IEEE/ASME Transactions on Mechatronics 18, 1300-1309. https://doi.org/10.1109/TMECH.2013.2258678Gertler, J., 2015. Fault detection and diagnosis. Encyclopedia of Systems and Control, 417-422. https://doi.org/10.1007/978-1-4471-5058-9_223Ghalamchi, B., Mueller, M., 2018. Vibration-based propeller fault diagnosis for multicopters, in: 2018 International Conference on Unmanned Aircraft Systems (ICUAS), IEEE. pp. 1041-1047. https://doi.org/10.1109/ICUAS.2018.8453400Guo, K., Liu, L., Shi, S., Liu, D., Peng, X., 2019. UAV sensor fault detection using a classifier without negative samples: A local density regulated optimization algorithm. Sensors 19, 771. https://doi.org/10.3390/s19040771Guzmán-Rabasa, J.A., López-Estrada, F.R., González-Contreras, B.M., Valencia-Palomo, G., Chadli, M., Pérez-Patricio, M., 2019. Actuator fault detection and isolation on a quadrotor unmanned aerial vehicle modeled as a linear parameter-varying system. Measurement and Control 52, 1228-1239. https://doi.org/10.1177/0020294018824764Iannace, G., Ciaburro, G., Trematerra, A., 2019. Fault diagnosis for UAV blades using artificial neural network. Robotics 8, 59. https://doi.org/10.3390/robotics8030059Jiang, Y., Zhiyao, Z., Haoxiang, L., Quan, Q., 2015. Fault detection and identification for quadrotor based on airframe vibration signals: a data-driven method, in: 2015 34th Chinese Control Conference (CCC), IEEE. pp. 6356- 6361. https://doi.org/10.1109/ChiCC.2015.7260639Jolliffe, I., 2011. Principal component analysis. Springer. https://doi.org/10.1007/978-3-642-04898-2_455Keipour, A., Mousaei, M., Scherer, S., 2019. 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Fault tolerant control of a quadrotor uav using sliding mode control, in: 2010 Conference on Control and Fault-Tolerant Systems (SysTol), IEEE. pp. 239-244. https://doi.org/10.1109/SYSTOL.2010.5675979Strang, G., Strang, G., Strang, G., Strang, G., 2016. Introduction to linear algebra. volume 3. Wellesley-Cambridge Press Wellesley, MA.Sun, R., Cheng, Q., Wang, G., Ochieng, W., 2017. A novel online data-driven algorithm for detecting UAV navigation sensor faults. Sensors 17, 2243. https://doi.org/10.3390/s17102243Tamura, M., Tsujita, S., 2007. A study on the number of principal components and sensitivity of fault detection using PCA. Computers & Chemical Engineering 31, 1035-1046. https://doi.org/10.1016/j.compchemeng.2006.09.004Valencia-Palomo, G., Villanueva-Grijalba, O., Robles-Ríos, R., 2018. Device for the pose measurement and test of control algoritms for unmanned aerial vehicles. Mexican Patent MX/a/2017/005377.Vapnik, V., 2013. The nature of statistical learning theory. 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    AGRONOMIC EVALUATION AND CHEMICAL COMPOSITION OF AFRICAN STAR GRASS (Cynodon plectostachyus) IN THE SOUTHERN REGION OF THE STATE OF MEXICO

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    African Star Grass is one of the forage resources most commonly used by farmers in regions with warm-humid climates. This study was carried out to determine the nutritional and agronomic characteristics of African Star Grass (Cynodon plectostachyus) through the following variables: crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), organic matter digestibility (OMD), net forage accumulation (NFA), stem:leaf ratio, and live:dead matter ratio in the three pastures evaluated. The work took place from April 2007 to March 2008, with evaluations carried out on a monthly basis. The data were analyzed in a randomized block design in which the blocks were the pastures, and the treatments were the months of evaluation. There were no differences between the pastures evaluated for the NDF, ADF or OMD (P>0.05). Differences were found, however, in CP, while in the monthly evaluation, differences were found between the periods evaluated (P<0.05) for these variables. Differences were also found in the agronomic evaluation of pastures (P<0.05) among height of pasture, net forage accumulation (NFA), live matter, dead matter, leaf and stem, both among pastures and in the monthly evaluations. African Star Grass can therefore be considered a good choice for milk production systems in the southern region of the state of Mexico, due to its nutritional and agronomic characteristics

    Statistically derived contributions of diverse human influences to twentieth-century temperature changes

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    The warming of the climate system is unequivocal as evidenced by an increase in global temperatures by 0.8 °C over the past century. However, the attribution of the observed warming to human activities remains less clear, particularly because of the apparent slow-down in warming since the late 1990s. Here we analyse radiative forcing and temperature time series with state-of-the-art statistical methods to address this question without climate model simulations. We show that long-term trends in total radiative forcing and temperatures have largely been determined by atmospheric greenhouse gas concentrations, and modulated by other radiative factors. We identify a pronounced increase in the growth rates of both temperatures and radiative forcing around 1960, which marks the onset of sustained global warming. Our analyses also reveal a contribution of human interventions to two periods when global warming slowed down. Our statistical analysis suggests that the reduction in the emissions of ozone-depleting substances under the Montreal Protocol, as well as a reduction in methane emissions, contributed to the lower rate of warming since the 1990s. Furthermore, we identify a contribution from the two world wars and the Great Depression to the documented cooling in the mid-twentieth century, through lower carbon dioxide emissions. We conclude that reductions in greenhouse gas emissions are effective in slowing the rate of warming in the short term.F.E. acknowledges financial support from the Consejo Nacional de Ciencia y Tecnologia (http://www.conacyt.gob.mx) under grant CONACYT-310026, as well as from PASPA DGAPA of the Universidad Nacional Autonoma de Mexico. (CONACYT-310026 - Consejo Nacional de Ciencia y Tecnologia; PASPA DGAPA of the Universidad Nacional Autonoma de Mexico

    Valproic acid restricts mast cell activation by Listeria monocytogenes.

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    Mast cells (MC) play a central role in the early containment of bacterial infections, such as that caused by Listeria monocytogenes (L.m). The mechanisms of MC activation induced by L.m infection are well known, so it is possible to evaluate whether they are susceptible to targeting and modulation by different drugs. Recent evidence indicates that valproic acid (VPA) inhibits the immune response which favors L.m pathogenesis in vivo. Herein, we examined the immunomodulatory effect of VPA on L.m-mediated MC activation. To this end, bone marrow-derived mast cells (BMMC) were pre-incubated with VPA and then stimulated with L.m. We found that VPA reduced MC degranulation and cytokine release induced by L.m. MC activation during L.m infection relies on Toll-Like Receptor 2 (TLR2) engagement, however VPA treatment did not affect MC TLR2 cell surface expression. Moreover, VPA was able to decrease MC activation by the classic TLR2 ligands, peptidoglycan and lipopeptide Pam3CSK4. VPA also reduced cytokine production in response to Listeriolysin O (LLO), which activates MC by a TLR2-independent mechanism. In addition, VPA decreased the activation of critical events on MC signaling cascades, such as the increase on intracellular Ca2+ and phosphorylation of p38, ERK1/2 and -p65 subunit of NF-κB. Altogether, our data demonstrate that VPA affects key cell signaling events that regulate MC activation following L.m infection. These results indicate that VPA can modulate the functional activity of different immune cells that participate in the control of L.m infection

    Estimación dinámica de parámetros para un modelo ecológico del Embalse Los Molinos

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    Fil: Rodriguez Reartes, S. B. Universidad Nacional del Sur. Consejo Nacional de Investigaciones Científicas y Técnicas. Planta Piloto de Ingeniería Química; Argentina.Fil: Estrada, V. Universidad Nacional del Sur. Consejo Nacional de Investigaciones Científicas y Técnicas. Planta Piloto de Ingeniería Química; Argentina.Fil: Bazán, R. Instituto Sup de Estudios Ambientales; Argentina.Fil: Bazán, R. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de química Industrial y Aplicada; Argentina.Fil: Larrosa, N. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de química Industrial y Aplicada; Argentina.Fil: Cossavella, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de química Industrial y Aplicada; Argentina.Fil: Cossavella, A. Instituto de Ciencia y Tecnología de Alimentos; Argentina.Fil: López, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de química Industrial y Aplicada; Argentina.Fil: López, A. Instituto de Ciencia y Tecnología de Alimentos; Argentina.Fil: Busso, F. Aguas Cordobesas S.A.; Argentina.Fil: Díaz, M. S. Universidad Nacional del Sur. Consejo Nacional de Investigaciones Científicas y Técnicas. Planta Piloto de Ingeniería Química; Argentina.En este trabajo, presentamos y calibramos un modelo de calidad de agua basado en primeros principios, el cual representa los procesos ecológicos a través de un complejo set de ecuaciones algebraicodiferenciales. El modelo requiere la estimación de numerosos parámetros para ajustar a las condiciones ambientales específicas del sitio en estudio. Se consideran los gradientes de las variables de estado a lo largo de la columna de agua, resultando en un sistema de ecuaciones algebraicas y diferenciales a derivadas parciales. Luego, el sistema es transformado a un sistema ordinario diferencial-algebraico (EDA) por discretización espacial del cuerpo de agua en capas horizontales. Los principales parámetros biogeoquímicos del modelo son obtenidos por resolución de un problema de estimación dinámica de parámetros, sujeto al EDA formulado. Los parámetros calculados permiten una representación apropiada de la dinámica del cuerpo de agua, como se muestra en los resultados numéricos.Fil: Rodriguez Reartes, S. B. Universidad Nacional del Sur. Consejo Nacional de Investigaciones Científicas y Técnicas. Planta Piloto de Ingeniería Química; Argentina.Fil: Estrada, V. Universidad Nacional del Sur. Consejo Nacional de Investigaciones Científicas y Técnicas. Planta Piloto de Ingeniería Química; Argentina.Fil: Bazán, R. Instituto Sup de Estudios Ambientales; Argentina.Fil: Bazán, R. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de química Industrial y Aplicada; Argentina.Fil: Larrosa, N. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de química Industrial y Aplicada; Argentina.Fil: Cossavella, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de química Industrial y Aplicada; Argentina.Fil: Cossavella, A. Instituto de Ciencia y Tecnología de Alimentos; Argentina.Fil: López, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de química Industrial y Aplicada; Argentina.Fil: López, A. Instituto de Ciencia y Tecnología de Alimentos; Argentina.Fil: Busso, F. Aguas Cordobesas S.A.; Argentina.Fil: Díaz, M. S. Universidad Nacional del Sur. Consejo Nacional de Investigaciones Científicas y Técnicas. Planta Piloto de Ingeniería Química; Argentina.Otras Ingeniería Químic
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