Increased efficiency in the second-hand tire trade provides opportunity for dengue control

Dengue fever is increasing in geographical range, spread by invasion of its vector mosquitoes. The trade in second-hand tires has been implicated as a factor in this process because they act as mobile reservoirs of mosquito eggs and larvae. Regional transportation of tires can create linkages between rural areas with dengue and disease-free urban areas, potentially giving rise to outbreaks even in areas with strong local control measures. In this work we sought to model the dynamics of mosquito transportation via the tire trade, in particular to predict its role in causing unexpected dengue outbreaks through vertical transmission of the virus across generations of mosquitoes. We also aimed to identify strategies for regulating the trade in second-hand tires, improving disease control. We created a mathematical model which captures the dynamics of dengue between rural and urban areas, taking into account the movement and storage time of tires, and mosquito diapause. We simulate a series of scenarios in which a mosquito population is introduced to a dengue-free area via movement of tires, either as single or multiple events, increasing the likelihood of a dengue outbreak. A persistent disease state can be induced regardless of whether urban conditions for an outbreak are met, and an existing endemic state can be enhanced by vector input. Finally we assess the potential for regulation of tire processing as a means of reducing the transmission of dengue fever using a specific case study from Puerto Rico. Our work demonstrates the importance of the second-hand tire trade in modulating the spread of dengue fever across regions, in particular its role in introducing dengue to disease-free areas. We propose that reduction of tire storage time and control of their movement can play a crucial role in containing dengue outbreaks

Exploring the Use of Fruit Callus Culture as a Model System to Study Color Development and Cell Wall Remodeling during Strawberry Fruit Ripening

Cell cultures derived from strawberry fruit at different developmental stages have been obtained to evaluate their potential use to study different aspects of strawberry ripening. Callus from leaf and cortical tissue of unripe-green, white, and mature-red strawberry fruits were induced in a medium supplemented with 11.3 µM 2,4-dichlorophenoxyacetic acid (2,4-D) under darkness. The transfer of the established callus from darkness to light induced the production of anthocyanin. The replacement of 2,4-D by abscisic acid (ABA) noticeably increased anthocyanin accumulation in green-fruit callus. Cell walls were isolated from the different fruit cell lines and from fruit receptacles at equivalent developmental stages and sequentially fractionated to obtain fractions enriched in soluble pectins, ester bound pectins, xyloglucans (XG), and matrix glycans tightly associated with cellulose microfibrils. These fractions were analyzed by cell wall carbohydrate microarrays. In fruit receptacle samples, pectins were abundant in all fractions, including those enriched in matrix glycans. The amount of pectin increased from green to white stage, and later these carbohydrates were solubilized in red fruit. Apparently, XG content was similar in white and red fruit, but the proportion of galactosylated XG increased in red fruit. Cell wall fractions from callus cultures were enriched in extensin and displayed a minor amount of pectins. Stronger signals of extensin Abs were detected in sodium carbonate fraction, suggesting that these proteins could be linked to pectins. Overall, the results obtained suggest that fruit cell lines could be used to analyze hormonal regulation of color development in strawberry but that the cell wall remodeling process associated with fruit softening might be masked by the high presence of extensin in callus cultures

Track trajectories with model uncertainty using a robust differentiator

[EN] In this article, we present the Levant’s Robust Differentiator applied to robot manipulators whose objective is to follow a desired trajectory. The robots’ dynamic model is unknown. The velocity obtained using the Robust Differentiator is applied in the control structure in order to fulfill the tracking task. A comparative study is made between the Levant’s Robust Differentiator and the most-used techniques to calculate the velocity. Experimental results are presented.[ES] En este artículo se presenta el uso de un diferenciador robusto de Levant aplicado a robots manipuladores cuyo objetivo es realizar el seguimiento de una trayectoria deseada. El modelo dinámico de los robots es desconocido. La velocidad obtenida empleando el diferenciador robusto se aplica en la estructura de control con la finalidad de cumplir con la tarea de seguimiento. Se realiza un estudio comparativo entre el diferenciador robusto de Levant y las técnicas más usadas para calcular la velocidad. Son presentados resultados experimentales.Los autores agradecen a PRODEP (PROMEP) con el número de Folio BUAP–811 y los proyectos PAPIIT 116314 y 114617 por el apoyo recibido, a CONACYT por la Cátedra CONACYT–CICESE 2017 y al Laboratorio de Robótica de la Facultad de Ciencias de la Electrónica de la Benemérita Universidad Autónoma de Puebla.Sánchez-Sánchez, P.; Gutiérrez–giles, A.; Pliego–jiménez, J.; Arteaga–pérez, M. (2019). Seguimiento de trayectorias con incertidumbre del modelo usando un diferenciador robusto. Revista Iberoamericana de Automática e Informática. 16(4):423-434. https://doi.org/10.4995/riai.2019.10265SWORD423434164Alcocer, A. and Robertsson, A. and Valera, A. and Johansson, R., 2003. Force Estimation and Control in Robot Manipulators. Proceedings of 7th Symposium on Robot Control (SYROCO'03) 55-60. Wroclaw, Poland https://doi.org/10.1016/S1474-6670(17)33369-4Atassi, A. N. and Khalil, H. K., 2000. Separation results for the stabilization of nonlinear systems using di_erent high-gain observer designs. Systems and Control Letters, 39(15), 183-191. https://doi.org/10.1016/S0167-6911(99)00085-7Berghuis, H. and Nijmeijer, H., 1994. Robust control of robots via linear estimated state feedback. IEEE Transactions on Automatic Control, 39(10), 2159-2162.https://doi.org/10.1109/9.328807Calafiore, G. and Indri, M. and Bona, B., 1997. Robot dynamic calibration: Optimal excitation trajectories and experimental parameter estimation. Journal of Robotic Systems 18(2), 55-68. https://doi.org/10.1002/1097-4563(200102)18:23.3.CO;2-FCruz-Zavala, E. and Moreno, J. A. and Fridman, L. M., 2010. Diferenciador Robusto Exacto y Uniforme. Proceedings of AMCA 2010, 1-6.Dabroom, A. M. and Khalil, H. K., 1994. Numerical differentiation using high gain observers. Proceedings of of the IEEE Conference on Decision and Control, 4790-4795. https://doi.org/10.1109/CDC.1997.649776Diop, S. and Grizzle, J. and Moraal, P. and Stefanopoulou, A., 1994. Interpolation and numerical differentiation for observer design. Proceedings of the American Control Conference, 1329-1333. https://doi.org/10.1109/ACC.1994.752275Hacksel, P. J. and Salcudean, S. E., 1994. Estimation of Environment Forces and Rigid-Body Velocities using Observers. Proc. IEEE International Conference on Robotics and Automation, 931-936. San Diego, CA, USA https://doi.org/10.1109/ROBOT.1994.351233Kelly, R. and Ortega, R. and Ailon, A. and Loria, A., 1994. Global regulation of flexible joint robots using approximate differentiation. IEEE Transactions on Automatic Control 39(6), 1222-1224. https://doi.org/10.1109/9.293181Kelly, R. and Santibáñez, V., 2003. Control de Movimiento de Robots Manipuladores. Prentice-HallKhalil, H. K., 1996. Nonlinear Systems. Prentice-HallKhatib, O., 1987. A Unified Approach for Motion and Force Control of Robot Manipulators: The Operational Space Formulation. IEEE Journal of Robotics and Automation 3(1), 43-53. https://doi.org/10.1109/JRA.1987.1087068Kumar, B. and Dutta-Roy, S. C., 1988. Design of digital differentiators for low frequencies. Proceedings of the IEEE, 76(3), 287-289. https://doi.org/10.1109/5.4408Levant, A., 1998. Sliding order and sliding accuracy in sliding mode control. International Journal of Control, 58(6), 1247-1263. https://doi.org/10.1080/00207179308923053Levant, A., 1998. Robust exact diferentiation via sliding mode technique. Automatica, 34(3), 379-384. https://doi.org/10.1016/S0005-1098(97)00209-4Levant, A., 2003. Higher-order sliding modes, diferentiation and output-feedback control. International Journal of Control, 76(9), 924-941. https://doi.org/10.1080/0020717031000099029Loria, A., 2016. Observers are Unnecessary for Output-Feedback Control of Lagrangian Systems. IEEE Transactions on Automatic Control, 61(4), 905- 920. https://doi.org/10.1109/TAC.2015.2446831Martínez-Rosas, J. C. and Arteaga-Pérez, M. A. and Castillo-Sánchez, A., 2006. Decentralized Control of Cooperative Robots without Velocity-Force Measurements. Automatica 42, 329-336. https://doi.org/10.1016/j.automatica.2005.10.007Martínez-Rosas, J. C. and Arteaga-Pérez, M. A., 2008. Force and Velocity Observers for the Control of Cooperative Robots. Robotica 26, 85-92. https://doi.org/10.1017/S026357470700361XMoreno, J. and Kelly, R., 2002. On motor velocity control by using only position measurements: two case studies. International Journal of Electrical Engineering Education 39(2), 118-127. https://doi.org/10.7227/IJEEE.39.2.4Nicosia, S. and Tornambe, A. and Valigi, P., 1990. Experimental results in state estimation of industrial robots. Proceedings of 29th IEEE Conference on Decision and Control, 360-365. https://doi.org/10.1109/CDC.1990.203613Parsa, K. and Aghili, F., 2006. Adaptive Observer for the Calibration of the Force-Moment Sensor of a Space Robot. Proceedings of the 2006 IEEE International Conference on Robotics and Automation, 1667-1673. Orlando, Florida. https://doi.org/10.1109/ROBOT.2006.1641946Rabiner, L. R. and Steiglitz, K., 1970. The design of wide-band recursive and nonrecursive digital differentiators. IEEE Transactions on Audio and Electroacoustics, 18(2), 204-209. https://doi.org/10.1109/TAU.1970.1162090Radkhah, K. and Kulic, D. and Croft, E., 2007. Dynamic parameter identification for the CRS A460 robot. Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems, 1-6. San Diego, CA, USA. https://doi.org/10.1109/IROS.2007.4399314Sira-Ramírez, H., 2005. Control de sistemas no lineales linealización aproximada, extendida, exacta. Pearson Prentice-HallStotsky, A. and Hedrick, J. K. and Yip, P. P., 1994. The use of sliding modes to simplify the backstepping control method. 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The nutraceutical antihypertensive action of C-phycocyanin in chronic kidney disease is related to the prevention of endothelial dysfunction

C-phycocyanin (CPC) is an antihypertensive that is not still wholly pharmacologically described. The aim of this study was to evaluate whether CPC counteracts endothelial dysfunction as an antihypertensive mechanism in rats with 5/6 nephrectomy (NFx) as a chronic kidney disease (CKD) model. Twenty-four male Wistar rats were divided into four groups: sham control, sham-treated with CPC (100 mg/Kg/d), NFx, and NFx treated with CPC. Blood pressure was measured each week, and renal function evaluated at the end of the treatment. Afterward, animals were euthanized, and their thoracic aortas were analyzed for endothelium functional test, oxidative stress, and NO production. 5/6 Nephrectomy caused hypertension increasing lipid peroxidation and ROS production, overexpression of inducible nitric oxide synthase (iNOS), reduction in the first-line antioxidant enzymes activities, and reduced-glutathione (GSH) with a down-expression of eNOS. The vasomotor response reduced endothelium-dependent vasodilation in aorta segments exposed to acetylcholine and sodium nitroprusside. However, the treatment with CPC prevented hypertension by reducing oxidative stress, NO system disturbance, and endothelial dysfunction. The CPC treatment did not prevent CKD-caused disturbance in the antioxidant enzymes activities. Therefore, CPC exhibited an antihypertensive activity while avoiding endothelial dysfunction

Synthesis of Nylon 6/Modified Carbon Black Nanocomposites for Application in Uric Acid Adsorption

High uric acid levels cause different clinic conditions. One of them is hyperuricemia, which leads to kidney damage. A solution for eliminating uric acid in the blood is by hemodialysis, which is performed using nanocomposite membranes. In this work, Nylon 6 nanocomposites were synthesized with modified carbon black (MCB), which were considered candidate materials for hemodialysis membranes. The modification of carbon black was made with citric acid using the variable-frequency ultrasound method. The new MCB was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), and dispersion tests. Nylon 6/MCB nanocomposites were processed using the ultrasound-assisted melt-extrusion method to improve the dispersion procedure of the nanoparticles. The Nylon 6/MCB nanocomposites were characterized by FTIR, TGA, and differential scanning calorimetry (DSC). These were assessed for the absorption of toxins and hemocompatibility. MBC and nanocomposites showed excellent uric acid removal (78–82%) and hemocompatibility (1.6–1.8%). These results suggest that Nylon 6/MCB nanocomposites with low loading percentages can be used on a large scale without compatibility problems with blood

Alteraciones en el sentido del olfato y del gusto en pacientes con enfermedad renal crónica, trasplante y diálisis y su asociación con el estado nutricional

Introducción: La insuficiencia renal crónica tiene alteraciones como lo son la anosmia y la disgeusia, estas ocasionadas por el incremento de toxinas urémicas, que se acompaña de un aumento del catabolismo, lo que incrementa la morbimortalidad. Estos pueden influir en la alimentación del paciente y por tanto en su estado nutricio. Objetivo: Analizar las evidencias encontradas en la literatura sobre la prevalencia, fisiopatología y tratamiento de la pérdida de gusto y olfato en pacientes con ERC, en HD, en DP y trasplantados renales y su asociación con el estado nutricional, para ello se inició una búsqueda en Pubmed, Scielo, Google académico, Published, Kydney Pediatric, Elsevier, Nutrición Hospitalaria, Society Kidney, Renut, American Society of Nephrology, Kidney Internationality con las siguientes palabras clave: Loss of kidney smell, Sense of taste, CDK, Kidney lost taste, sense of smell, nutritional status (para el idioma inglés), insuficiencia renal, pérdida del gusto, pérdida de sentidos, pérdida de olfato, estado de nutrición (para el idioma español). Resultados: Se muestra la relación existente de la pérdida del olfato con el grado de insuficiencia renal y el grado de acumulación de toxinas urémicas. Respecto al gusto, se ha descrito disminución por déficit de zinc y eliminación de urea por medio de la saliva, por la percepción alterada en estos pacientes de hemodiálisis prevalentemente asociada de forma independiente con índices en déficits por el estado nutricional y teniendo una mayor mortalidad. Conclusiones: La pérdida del olfato, del gusto o ambas es una condición frecuente en los pacientes con insuficiencia renal crónica y contribuye al riesgo nutricional de estos pacientes. Key words: Renal, sentido del olfato, diálisis, sentido del gusto, estado nutrici

Phylogeny and morphology determine vulnerability to global warming in Pristimantis frogs

Global warming is a great threat to biodiversity with negative impacts spanning the entire biological hierarchy. One of the main species’ traits determining survival at higher temperature is the thermal point at which an animal loses its ability to escape from deadly conditions (critical thermal maximum—CTmax). Variation in CTmax across species is the outcome of environmental and evolutionary factors, but studies do not typically measure the degree to which environment or phylogeny influences the variation in trait values. Here, we aim to elucidate whether local environmental variables or phylogeny influence CTmax in highly climate change-threatened amphibians in the Tropical Andes. We measured CTmax from 204 individuals belonging to seven Pristimantis frog species encountered in primary and secondary forests, and cattle pastures. We recorded their habitat, elevation, and the range of environmental temperatures they experienced over one year. Using phylogenetic analyses, we demonstrate that physiological thermal tolerance is related to phylogeny, positively related to body length, but not affected by environmental factors. We suggest that both phylogeny and morphology determine vulnerability to global warming

Effect of Microwave Radiation on the Synthesis of Poly(3-hexylthiophene) and the Subsequent Photovoltaic Performance of CdS/P3HT Solar Cells

Poly(3-hexylthiophene) (P3HT) is a semiconductor polymer that has been proved to be a good electron donor in organic or hybrid solar cells. In this work, a detailed study of P3HT synthesis in CH2Cl2 solvent by oxidative method with and without MW assistance has been conducted. Effects of synthesis process parameters on the physical properties of P3HT products and their application in hybrid CdS/P3HT photovoltaic devices were studied. It is observed that the use of MW as well as the reaction time affected the reaction yield and properties of the polymer products. It was found that, by the traditional method (without MW), the maximum yield and the properties of the polymer products were similar after 2 h or 24 h of synthesis. The optimal reaction time with MW for P3HT polymerization in CH2Cl2 solvent was 1 h, and the obtained P3HT product showed similar or better properties than those P3HT polymers synthesized by the traditional method in the same solvent. The effect of using MW during the synthesis was to increase yield and crystal size of P3HT. Larger energy conversion efficiency of ITO/CdS/P3HT/CP-Au devices was obtained when the P3HT product had higher molecular weight and head/tail-head/tail (HT-HT) triad contents