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Santa Rosa Jauregui, Mexico

Martinez-Castillo M.,National Polytechnic Institute of Mexico | Ramirez-Rico G.,Mexican Center for Research and Advanced Studies | Ramirez-Rico G.,University of Cuautitlan Izcalli | Serrano-Luna J.,Mexican Center for Research and Advanced Studies | Shibayama M.,National Polytechnic Institute of Mexico
BioMed Research International | Year: 2015

Naegleria fowleri causes acute and fulminant primary amoebic meningoencephalitis. This microorganism invades its host by penetrating the olfactory mucosa and then traveling up the mesaxonal spaces and crossing the cribriform plate; finally, the trophozoites invade the olfactory bulbs. During its invasion, the protozoan obtains nutrients such as proteins, lipids, carbohydrates, and cationic ions (e.g., iron, calcium, and sodium) from the host. However, the mechanism by which these ions are obtained, particularly iron, is poorly understood. In the present study, we evaluated the ability of N. fowleri to degrade iron-binding proteins, including hololactoferrin, transferrin, ferritin, and hemoglobin. Zymography assays were performed for each substrate under physiological conditions (pH 7 at 37°C) employing conditioned medium (CM) and total crude extracts (TCEs) of N. fowleri. Different degradation patterns with CM were observed for hololactoferrin, transferrin, and hemoglobin; however, CM did not cause ferritin degradation. In contrast, the TCEs degraded only hololactoferrin and transferrin. Inhibition assays revealed that cysteine proteases were involved in this process. Based on these results, we suggest that CM and TCEs of N. fowleri degrade iron-binding proteins by employing cysteine proteases, which enables the parasite to obtain iron to survive while invading the central nervous system. © 2015 Moisés Martínez-Castillo et al. Source

Rivera-Torres S.,Metropolitan Autonomous University | Del Rio F.,Metropolitan Autonomous University | Espindola-Heredia R.,Metropolitan Autonomous University | Espindola-Heredia R.,University of Cuautitlan Izcalli | And 2 more authors.
Journal of Molecular Liquids | Year: 2013

The high-temperature expansion of the free energy of a fluid of square wells, SW, is considered. The first four terms in this expansion are calculated for SW systems of variable range λσ, where σ is the diameter of the spherical hard-core. The properties were calculated via molecular dynamics, MD, for ranges 1 ≤ λ ≤ 2.5 with special emphasis on the region of shorter ranges: λ = 1.025, 1.050, 1.075, 1.100, 1.125 and 1.150. The principal aims are to compare these results with the previous ones obtained using the Monte Carlo, MC, method (Espíndola-Heredia et al. J. Chem. Phys. 130, 024509 (2009)) that showed large statistical noise in the higher-order terms at high densities, and to provide a benchmark to check the theoretical Short-Range Expansion of the free energy of these systems. The results have been corrected to obtain the thermodynamic limit via a change of ensemble algorithm and by simulating systems with 125, 200, 500 and 1000 particles. The MD results are much smoother that the corresponding MC data and their precision allow to determine the behavior of the series for high densities. The simulation results are used to test a theory built to write the free energy for short ranges. The position of the critical point is calculated with this theory for very short ranges. © 2012 Elsevier B.V. Source

Bologna-Molina R.,University of Guadalajara | Gonzalez-Gonzalez R.,University of Cuautitlan Izcalli | Mosqueda-Taylor A.,Metropolitan Autonomous University | Molina-Frechero N.,Metropolitan Autonomous University | And 2 more authors.
Archives of Medical Research | Year: 2010

Background and Aims: Syndecan-1 (SDC-1) is a member of the family of transmembrane heparan sulfate proteoglycans, which are involved in cell-cell adhesion and the interaction of cells with the extracellular matrix. Evidence suggests that loss of SDC-1 expression in several benign and malignant epithelial neoplasms is an unfavorable prognostic indicator, but its expression profile in thyroid gland neoplasms remains to be elucidated. The aim of this study was to evaluate SDC-1 expression in papillary carcinomas of the thyroid (PCT) that were both larger and smaller (papillary microcarcinoma) than 10. mm, with or without extracapsular extension (PCT-E and PCT-NE). Methods: The expression of SDC-1 was studied in 62 cases of PCT-E and PCT-NE using a tissue microarrays technique (TMA). SDC-1 positivity was predominantly observed in the cytoplasm of neoplastic epithelial cells and in the stroma of PCT. Results: SDC-1 is expressed in both neoplastic epithelial cells and the stroma. It is more frequently expressed in PCT-E than PCT-NE (p=0.002) and the stromal expression of SDC-1 is more intense in PCT-E that are >10 mm (p=0.026). Conclusions: The epithelial and stromal expression of SDC-1 observed in this series of PCT suggests that the expression of this protein may be related to extracapsular invasion. © 2010 IMSS. Source

Martinez-Fonseca N.,Av. Acueducto S N Col. | Castaneda L.A.,National Polytechnic Institute of Mexico | Uranga A.,University of Cuautitlan Izcalli | Luviano-Juarez A.,National Polytechnic Institute of Mexico | Chairez I.,Av. Acueducto S N Col.
ISA Transactions | Year: 2016

This study addressed the problem of robust control of a biped robot based on disturbance estimation. Active disturbance rejection control was the paradigm used for controlling the biped robot by direct active estimation. A robust controller was developed to implement disturbance cancelation based on a linear extended state observer of high gain class. A robust high-gain scheme was proposed for developing a state estimator of the biped robot despite poor knowledge of the plant and the presence of uncertainties. The estimated states provided by the state estimator were used to implement a feedback controller that was effective in actively rejecting the perturbations as well as forcing the trajectory tracking error to within a small vicinity of the origin. The theoretical convergence of the tracking error was proven using the Lyapunov theory. The controller was implemented by numerical simulations that showed the convergence of the tracking error. A comparison with a high-order sliding-mode-observer-based controller confirmed the superior performance of the controller using the robust observer introduced in this study. Finally, the proposed controller was implemented on an actual biped robot using an embedded hardware-in-the-loop strategy. © 2016 ISA. Source

Flores-Conde M.I.,Polytechnic School of Algiers | Reyes L.,Polytechnic School of Algiers | Herrera R.,Universidad Michoacana de San Nicolas de Hidalgo | Rios H.,University of Cuautitlan Izcalli | And 4 more authors.
International Journal of Molecular Sciences | Year: 2012

Infrared irradiation promoted the Diels-Alder cycloadditions of exo-2-oxazolidinone dienes 1-3 with the Knoevenagel adducts 4-6, as dienophiles, leading to the synthesis of new 3,5-diphenyltetrahydrobenzo[d]oxazol-2-one derivatives (7, 9, 11 and 13-17), under solvent-free conditions. These cycloadditions were performed with good regio- and stereoselectivity, favoring the para-endo cycloadducts. We also evaluated the one-pot three-component reaction of active methylene compounds 20, benzaldehydes 21 and exo-2-oxazolidinone diene 2 under the same reaction conditions. A cascade Knoevenagel condensation/Diels-Alder cycloaddition reaction was observed, resulting in the final adducts 13-16 in similar yields. These procedures are environmentally benign, because no solvent and no catalyst were employed in these processes. The regioselectivity of these reactions was rationalized by Frontier Molecular Orbital (FMO) calculations. © 2012 by the authors; licensee MDPI, Basel, Switzerland. Source

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