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Herrera-Valencia E.E.,National Autonomous University of Mexico | Calderas F.,CIATEC | Medina-Torres L.,National Autonomous University of Mexico | Perez-Camacho M.,National Autonomous University of Mexico | And 2 more authors.
Rheologica Acta | Year: 2017

In this work, the rectilinear flow of a complex fluid (human blood) under a pulsating time-dependent pressure gradient is analyzed. A first approximation of the real case of blood flowing in a vein is described. The normalized pressure gradient simulates the pumping work of the heart while the flow geometry (circular tube) is assumed rigid, smooth, and cylindrical. The rheological behavior of blood with different cholesterol levels is modeled using the Bautista–Manero–Puig (BMP) constitutive equation. According to the analytical solution, a flow enhancement is predicted to first order which represents the optimum pumping work of the heart which governs the flow of blood in the entire body. This work is a contribution to the understanding of the complex rheology involved in the discontinuous pressure-driven flow of blood in the human body. © 2017, Springer-Verlag Berlin Heidelberg.

Aguilar-Dorado I.-C.,Research Center y Estudios Avanzados | Hernandez G.,Research Center y Estudios Avanzados | Quintanar-Escorza M.-A.,University of Sfax | Maldonado-Vega M.,CIATEC | And 2 more authors.
Toxicology and Applied Pharmacology | Year: 2014

Eryptosis is a physiological phenomenon in which old and damaged erythrocytes are removed from circulation. Erythrocytes incubated with lead have exhibited major eryptosis. In the present work we found evidence of high levels of eryptosis in lead exposed workers possibly via oxidation. Blood samples were taken from 40 male workers exposed to lead (mean blood lead concentration 64.8μg/dl) and non-exposed workers (4.2μg/dl). The exposure to lead produced an intoxication characterized by 88.3% less δ-aminolevulinic acid dehydratase (δALAD) activity in lead exposed workers with respect to non-lead exposed workers. An increment of oxidation in lead exposed workers was characterized by 2.4 times higher thiobarbituric acid-reactive substance (TBARS) concentration and 32.8% lower reduced/oxidized glutathione (GSH/GSSG) ratio. Oxidative stress in erythrocytes of lead exposed workers is expressed in 192% higher free calcium concentration [Ca2+]i and 1.6 times higher μ-calpain activity with respect to non-lead exposed workers. The adenosine triphosphate (ATP) concentration was not significantly different between the two worker groups. No externalization of phosphatidylserine (PS) was found in non-lead exposed workers (<0.1%), but lead exposed workers showed 2.82% externalization. Lead intoxication induces eryptosis possibly through a molecular pathway that includes oxidation, depletion of reduced glutathione (GSH), increment of [Ca2+], μ-calpain activation and externalization of PS in erythrocytes. Identifying molecular signals that induce eryptosis in lead intoxication is necessary to understand its physiopathology and chronic complications. © 2014 Elsevier Inc.

Rendon-Ramirez A.-L.,Research Center y Estudios Avanzados | Maldonado-Vega M.,CIATEC | Quintanar-Escorza M.-A.,University of Sfax | Hernandez G.,Research Center y Estudios Avanzados | And 3 more authors.
Environmental Toxicology and Pharmacology | Year: 2014

The molecular response of the antioxidant system and the effects of antioxidant supplementation against oxidative insult in lead-exposed workers has not been sufficiently studied. In this work, antioxidants (vitamin E 400. IU. +. vitamin. C 1. g/daily) were supplemented for one year to 15 workers exposed to lead (73. μg of lead/dl of blood) and the results were compared with those on 19 non-lead exposed workers (6.7. μg of lead/dl). Lead intoxication was accompanied by a high oxidative damage and an increment in the erythrocyte antioxidant response due to increased activity of catalase and superoxide dismutase. Antioxidant supplementations decreased significantly the oxidative damage as well as the total antioxidant capacity induced by lead intoxication with reduction of the antioxidant enzyme activities. We conclude that antioxidant supplementation is effective in reducing oxidative damage and induces modifications in the physiopathological status of the antioxidant response in lead-exposed workers. © 2013 Elsevier B.V.

Medina-Torres L.,National Autonomous University of Mexico | GarcIa-Cruz E.E.,National Polytechnic Institute of Mexico | Calderas F.,National Autonomous University of Mexico | Gonzalez Laredo R.F.,Durango Institute of Technology | And 4 more authors.
LWT - Food Science and Technology | Year: 2013

The spray-drying process has been previously used to encapsulate food ingredients such as antioxidants. Thus the objective of this work was to produce microcapsules of gallic acid, a phenolic compound that acts as antioxidant, by spray drying with an aqueous extract of nopal mucilage (Ofi), which acted as an encapsulating agent. The rheological response and the particle size distribution of the final solutions containing gallic acid at concentrations of 6 g/100 mL were characterized along with the control sample, no gallic acid added, to elucidate the degree of encapsulation. The drying parameters to prepare the microcapsules with extract of nopal mucilage were: inlet air temperature (130 and 170 °C) and speed atomization (14,000 and 20,000 rpm). The rehydrated biopolymer showed a non-Newtonian pseudoplastic behavior. The Cross Model was used to model the rheological data. Values for ". m" varied between 0.55 and 0.85, and for " time characteristic,. λ", the range was between 0.0071 and 0.021 s. The mechanical spectra showed that the sample with gallic acid was stable long term (>2 days) and presented a bimodal particle size distribution. This study demonstrated the effectiveness of nopal mucilage when utilized as wall biomaterial in microencapsulation of gallic acid by the spray-drying process. © 2012 Elsevier Ltd.

Perez-Rodriguez R.,CIATEC | Jons S.,University of Guanajuato | Hernandez-Aguirre A.,CIMAT | Alberto-Ochoa C.,UACJ
International Journal of Advanced Manufacturing Technology | Year: 2014

The flexible jobshop scheduling problem permits the operation of each job to be processed by more than one machine. The idea is to assign the processing sequence of operations on the machines and the assignment of operations on machines such that the systemobjectives can be optimized. The assignment mentioned is a difficult task to implement on real manufacturing environments because there are many assumptions to satisfy, especially when the amount of work is not constant or sufficient to keep the manufacturing process busy for a long time, causing intermittent idle times. An estimation of distribution algorithm-based approach coupled with a simulationmodel is developed to solve the problemand implement the solution. Using the proposed approach, the shop performance can be noticeably improved when different machines are assigned to different schedules. © Springer-Verlag London 2014.

The proposed work describes the construction of a compact dehydrated hybrid system with solar energy application using cylindrical-parabolic collectors (CPC), whose reflective material is stainless steel. This material is vital to the system due to the steel plates' high durability and hardness above 190 vickers, and their easy acquisition. Using a standard polishing process the maximum height of the roughness, among other parameters was reduced considerably. The maximum average efficiency reflective was 0.70. With this a PTC is herein presented able to achieve sufficient thermal efficiency capable of covering the energy demand of processes such as is the case with the chili-pepper dehydration. Its efficiency is validated by the comparison with other CPCs commercially available, with similar characteristics.The proposed CPC system has a brick tunnel coated internally with cement. Its dimensions are 1.8 m x 2.3 m x 21 m and a conventional energy support module. The product is placed on racks inside the tunnel, through which hot air flows injected by means of a fan. The required temperature ranges from 70 to 90 °C, depending on the type of product. The drying time is about 36 hours. Its main advantages over other dehydrating thermal systems using fossil fuels are that it has a cost reduction of approximately 40% with a similar reduced greenhouse gas emission, while also being able to dehydrate large quantities of product.

Moreno A.A.S.,CIATEC | Gutierrez F.C.,Technical University del Bicentenario
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

Nowadays the measurement of the contact area of the foot has become an objective way of classifying feet and to describe the form of the longitudinal arch of the foot. In this work, the implementation of a digital podoscope that enables remote sensing for evaluation of the foot is described. The podogram includes an outline of the plantar pressure, and the contour of the arch. This method of evaluation is relatively simple and inexpensive while maintaining precision. The recognition system compares the image of the actual foot with that of a reference image. Information from the comparison can be sent by internet to obtain a remote diagnosis from an expert. © 2011 SPIE.

Purata O.J.,University of Guanajuato | De La O. J.,CIATEC | Funes E.,CIATEC
XXI IMEKO World Congress "Measurement in Research and Industry" | Year: 2015

A noncontact test method for the volume determination of weights from (1 to 1 000) g is described. The method uses an optical comparator to size cylindrical weights, and allows to compute the volume of the weight according to OIML R 111-1 Method E. The volume values obtained for the weights were compared against hydrostatic weighing volume results for reference. The volume relative uncertainty levels reached with the optical comparator are small enough for calibration operations of even OIML Class E2 weights.

Cruz O.,CIATEC | Santos R.,Technical University Zacatecas
IIE Annual Conference and Expo 2013 | Year: 2013

This article presents a choice to improve the process of assigning storage allocations in a warehouse. The main inconvenient frequently in these situations are, that existing techniques like model assignment or plant layout representations require the compliance of some assumptions that commonly do not appear in reality. Sometimes it is necessary to deal with complex and diverse variables that make the use of traditional tools difficult. Therefore, considering the complexity of the problem, this document is presented as an alternative to improve the mentioned process. The document is based on simulation using FLEXSIM® and artificial neural networks, considering the problem linearly separable.

Monje A.E.,CIATEC | Resendiz J.R.H.,A. P Resinas
Materials Research Society Symposium Proceedings | Year: 2013

The antimicrobial properties of polymer materials are used in a verity of applications. Silver nanoparticles are commonly applied to polyurethane foams to obtain antifungal properties. For this study a series of nanocomposites (PU-Ag) from a urethane-type polymer (PU) were reinforced with various amounts of silver nanoparticles having an average size of 20 nm. The surface morphology and antifungal capacity of the nanocomposites were evaluated. As a result, a different surface morphology from PU was found in PU-Ag nanocomposites. The latter nanocomposite showed enhanced thermal and mechanical properties, when compared with the PU without silver nanoaprticles. The nanocomposite also exhibited good antifungal properties that can be used in a variety of applications. © 2013 Materials Research Society.

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