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Synthesis and Structural Characterization of Monocrystalline α-v₂O₅ nanowires

Materials Sciences and Applications 2016年第9期7卷 484-495页

作者： María luisa Tafoya Ronquillo Patricia Santiago Jacinto Pilar Ovalle luis rendón vázquez Elizabeth Chavira Martínez Ernesto Marinero vicente Garibay Instituto de Física UNAM Circuito de la Investigación s/n Ciudad Universitaria México D.F. México Instituto de Investigaciones en Materiales UNAM Circuito de la Investigación s/n Ciudad Universitaria México D.F. México Purdue University Purdue Mall West Lafayette IN USA Instituto Mexicano del Petróleo IMP México D.F. México

A stable one-dimensional system in an orthorhombic α-v2O5 nanowires monocrystalline structure was obtained by a solvothermal method from a polymorphic v2O5 structure. The starting material was firstly submitted to acid hydrolysis in H2O2 followed by a solvothermal treatment. The outcome of this procedure, a metastable phase of the one-dimensional system v10O24·12H2O/v3O7·H2O, was subsequently reoxidized by controlled heating in an open air system. The final product was an orange crystalline solid mainly formed by monocrystalline nanowires of α-v2O5 having lengths of tens of micrometers and widths of about 75 nm with a preferential [200] growth direction. It was found that the pH value of the initial solution plays an important role in the formation of the crystalline phase in the final products. Characterization was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). This study offers an alternate route for the synthesis of vanadium oxides and related compounds.

关键词： nanostructures Oxides Crystal Growth X-Ray Diffraction Crystal Structure

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Microstructural Characterization of Large Area C<sub>60</sub>Films Obtained by Conventional Microwave Oven Irradiation

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World Journal of nano Science and Engineering 2012年第4期2卷 213-218页

作者： Jacobo Martínez-Reyes Lucia Graciela Díaz Barriga-Arceo luis rendón-vazquez Reynaldo Martínez-Guerrero néstor Romero-Partida Eduardo Palacios-González vicente Garibay-Febles Jaime Ortiz-López IMP-Molecular Engineering Program México City México national Polytechnic Institute (IPn) ESFM UPALM México City México national Polytechnic Institute (IPn) ESIQIE UPALM México City México ROMFER S.A. de C.v. México City México UnAM-FCiencias México City México

In the present work the synthesis of C60 produced in a conventional microwave oven from the decomposition of camphor resin is reported. The polycrystalline structure of the sample was determined by X-Ray Diffraction (XRD), the sample showed several phases, the main phase corresponds to fullerene C60 ordered in a Face-Centered Cubic structure (FCC), with two more structures: one orthorhombic system and the other the monoclinic system coexisting also with graphite 2H phase. It was observed in a Scanning Electron Microscopy (SEM), that the sample formed thin films of stacked carbon. Whereas in a High Resolution Transmission Electron Microscopy (HRTEM), measurements in Bright Field mode revealed that the main phase of the material is C60 ordered in FCC structure and the elemental composition and atomic bonding state can be determined by analyzing the energy with the electron microscope by Elesctron Energy- Loss Spectroscopy (EELS), technique allowed confirm all the phase C60 established with XRD observations.

关键词： Microwave-Assisted Synthesis Carbon Film Fullerene

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Motor-Cognitive Intervention in Mexican Older Adults

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Health 2016年第13期8卷 1368-1380页

作者： luis rendón-Torres Bertha Cecilia Salazar-González Esther Gallegos-Cabriales Perla Lizeth Hernández-Cortés Ernesto O. López-Ramirez Marco vinicio Gómez-Meza Facultad de Enfermería Universidad Autónoma de Tamaulipas Laredo Mexico Facultad de Enfermería Universidad Autónoma de Nuevo León Nuevo León Mexico Facultad de Psicología Universidad Autónoma de Nuevo León Nuevo León Mexico Facultad de Economía Universidad Autónoma de Nuevo León Nuevo León Mexico

Two motor-cognitive interventions were implemented to evaluate their efficacy in cognitive improvement in Mexican older adults 65 years and more. The intervention group received a dance video games plus a cognitive task (dual-task);the comparison group received only the dance video game, in sessions of 45 minutes, 3 times a week, for 12 weeks. The Barthel Index and Lawton and Brody Index, the Center for Epidemiologic Studies Depression Scale-Revised were applied the Digit Span Test, the Stroop Test, and Color Trail Making. Gait parameters were assessed by GAITRite? electronic walkway (CIR Systems). The design was quasi-experimental. Sites were randomly assigned to intervention groups. The intervention group started with 32 participants and finished with 15;the comparison group started with 20 participants and finished with 18. Participants in the intervention group had to mimic the dance movement of a video game and, after the second week to name progressively three objects without stopping dancing. A multivariate repeated measures model (MAnO-vA) was fit with four variables. A time-by-group interaction was observed in the Stroop test, and Digits Span Backwards was in favor of the dual task group. The Stroop test, Digit Span Backwards, gait speed, and step length showed effect time. Both groups improved in gait speed and step length by the end of the intervention. Results show it is feasible for Mexican older adults with little schooling to perform dual tasks and improve cognitive tasks and gait speed. Limitations were high attrition due to unforeseen situations and small sample size.

关键词： Dual Task Elderly Cognition Intervention Study

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