Time filter

Source Type

Santiago de Queretaro, Mexico

Arora P.K.,Chandigarh Institute of Microbial Technology | Arora P.K.,Central University of Costa Rica | Sharma A.,Queretaro Institute of Technology | Mehta R.,Autonomous University of the State of Morelos | And 3 more authors.
Microbial Cell Factories | Year: 2012

Background: Chloronitrophenols (CNPs) are widely used in the synthesis of dyes, drugs and pesticides, and constitute a major group of environmental pollutants. 4-Chloro-2-nitrophenol (4C2NP) is an isomer of CNPs that has been detected in various industrial effluents. A number of physicochemical methods have been used for treatment of wastewater containing 4C2NP. These methods are not as effective as microbial degradation, however.Results: A 4C2NP-degrading bacterium, Exiguobacterium sp. PMA, which uses 4C2NP as the sole carbon and energy source was isolated from a chemically-contaminated site in India. Exiguobacterium sp. PMA degraded 4C2NP with the release of stoichiometeric amounts of chloride and ammonium ions. The effects of different substrate concentrations and various inoculum sizes on degradation of 4C2NP were investigated. Exiguobacterium sp. PMA degraded 4C2NP up to a concentration of 0.6 mM. High performance liquid chromatography and gas chromatography-mass spectrometry identified 4-chloro-2-aminophenol (4C2AP) and 2-aminophenol (2AP) as possible metabolites of the 4C2NP degradation pathway. The crude extract of 4C2NP-induced PMA cells contained enzymatic activity for 4C2NP reductase and 4C2AP dehalogenase, suggesting the involvement of these enzymes in the degradation of 4C2NP. Microcosm studies using sterile and non-sterile soils spiked with 4C2NP were carried out to monitor the bioremediation potential of Exiguobacterium sp. PMA. The bioremediation of 4C2NP by Exiguobacterium sp. PMA was faster in non-sterilized soil than sterilized soil.Conclusions: Our studies indicate that Exiguobacterium sp. PMA may be useful for the bioremediation of 4C2NP-contaminated sites. This is the first report of (i) the formation of 2AP in the 4C2NP degradation pathway by any bacterium and (iii) the bioremediation of 4C2NP by any bacterium. © 2012 Arora et al.; licensee BioMed Central Ltd.

Montes L.G.A.,National Autonomous University of Mexico | Ricardo-Garcell J.,National Autonomous University of Mexico | de la Torre L.B.,Queretaro Institute of Technology | Fernandez-Bouzas A.,National Autonomous University of Mexico | Acosta D.A.,National Autonomous University of Mexico
Journal of Psychiatry and Neuroscience | Year: 2010

Background: Magnetic resonance imaging (MRI) studies have shown decreased caudate volumes in individuals with attention deficit hyperactivity disorder (ADHD). However, most of these studies have been carried out in male children. Very little research has been done in adults, and the results obtained in children are difficult to extrapolate to adults. We sought to compare the volume of the caudate of adults with ADHD with that of healthy controls; we also compared these volumes between men and women. Methods: We performed an MRI scan on 20 adults with ADHD (10 men and 10 women) aged 25-35 years and 20 healthy controls matched by age and sex. We used voxel-based morphometry with the DARTEL algorithm for image analyses. We used the specifically designed Friederichsen, Almeida, Serrano, Cortes Test (FASCT) to measure the severity of ADHD; both the self-reported (FASCT-SR) and the observer (FASCT-O) versions were used. Results: The statistical parametric map showed a smaller region with low grey matter volume and a smaller concentration of grey matter in this region of the right caudate in ADHD patients than in health controls, both in the entire sample and within each sex. There was a significant correlation between the volume of this region of the caudate with the number of DSM IV-TR criteria, as well as with the total scores and most of the factors of the FASCT-SR and FASCT-O scales. A separate correlation analysis by sex gave similar results. Limitations: The study design was cross-sectional. Conclusion: The region of the right caudate with low grey matter volume was smaller in adults with ADHD in both sexes and was correlated with ADHD severity. © 2010 Canadian Medical Association.

Sandoval-Castro X.Y.,Research Center en Ciencia Aplicada y Tecnologia Avanzada | Garcia-Murillo M.,Research Center en Ciencia Aplicada y Tecnologia Avanzada | Perez-Resendiz L.A.,Queretaro Institute of Technology | Castillo-Castaneda E.,Research Center en Ciencia Aplicada y Tecnologia Avanzada
International Journal of Advanced Robotic Systems | Year: 2013

In this paper the kinematic analysis of a six-legged robot, hereafter named Hex-piderix, is carried out. A three revolute (3R) chain has been chosen for each limb in order to mimic the leg structure of an insect. The rotation matrix, with unitary vectors, and the Denavit-Hartenberg (D-H) conventions are used to find the pose of the thorax. The problem of inverse position is solved by geometrical analysis. The direct and inverse infinitesimal kinematics are obtained by the reciprocal screw theory, considering a suction cup attached to each leg and modelling it as a UP linkage. A numerical example of the thorax pose was made by solving the equations obtained from the direct position analysis. The equations of the inverse position analysis were solved to obtain the angles of the joints. Finally, the velocity values of the thorax obtained from the infinitesimal kinematics were validated by simulating the movements of Hex-piderix using specialized software. © 2013 Sandoval-Castro et al.; licensee InTech.

Cardador-Martinez A.,Research Center Asistencia Tecnologia Diseno del Estado Jalisco | Cardador-Martinez A.,Queretaro Institute of Technology | Jimenez-Martinez C.,Escuela Nacional de Ciencias Biologicas IPN | Sandoval G.,Research Center Asistencia Tecnologia Diseno del Estado Jalisco
Ciencia e Tecnologia de Alimentos | Year: 2011

Recently, an increased interest in antioxidant activity and health-improving capacity of cactus pear has been registered. The antioxidant capacity of the pulp of cactus-pear fruits has been previously assessed. In this work, total phenolics, flavonoids and tannins of peel and seeds of four cactus pear cultivars were examined as well as their antioxidant capacity. Tannins were the major phenolics in cactus pear seeds accounting for almost fifty percent for all cultivars. Analysis of variance revealed that ripeness, cultivar, and its interaction had highly significant effect on the total phenolics, tannin, and flavonoid contents of cactus pear peel. With regard to the seeds, only the stage of ripeness and interaction (ripeness stage × cultivar) were significant on total phenolics and tannins contents. The flavonoid content in seeds was not affected by any of the factors or their interactions. The antioxidant capacity was higher in the peel than in the seeds. Generally, fruits with light-green or yellow-brown peel have higher antiradical activity and Trolox equivalent antioxidant capacity (TEAC) values compared with those with red-purple peel. Cactus pear by-products can indeed be exploited as a good and cheap source of natural antioxidants.

Dodero J.M.,University of Cadiz | del Val A.M.,University of Cadiz | Torres J.,Queretaro Institute of Technology
Journal of Visual Languages and Computing | Year: 2010

Learning management systems (LMS) provide an operational environment in which an online course can be created and later executed. Inter-operation between creators and their authoring facilities, and the LMS execution engine are based on defining standards and specifications, such as the IMS Learning Design (LD). Because an LMS better serves as a course player than as a course creator, a large number of approaches and environments for standards-compliant course authoring have been developed. These approaches and environments propose a number of issues that deal with how adaptations are edited and how to define the connection of learning activities with external learning applications and services. These questions have raised concern, mostly because of the excessive commitment of the creators' methods and tools used with an educational modeling language, as well as the isolation of the language used to describe the course from the host LMS. This work describes an abstract, extendible language used to specify the learning design of a course, which can be transformed into any LD language as required by the execution environment. The language is used from a generative authoring environment that offers the possibility of editing web services as an additional resource to assess learning activities. © 2010 Elsevier Ltd.

Discover hidden collaborations