2,368 research outputs found

    Synthesis and characterization of silver vanadates thin films for photocatalytic applications

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    Silver vanadates thin films were deposited by a hybrid deposition system combining laser ablation and thermal evaporation. A high purity vanadium target was ablated using the third harmonic of a Nd:YAG laser whereas high purity silver pellets were evaporated. The as-deposited thin films were subjected to thermal treatments at 400 °C to obtain crystalline films. For films without Ag amorphous V2O5 thin films were deposited and as the Ag is incorporated in the material different silver vanadates were obtained. The effect of the silver load on the composition, structure, optical properties, surface morphology and photocatalytic response of the deposited films was studied. The film composition, determined by X-ray photoelectron spectroscopy, reveals Ag contents from 5.5 to 18.9 at.%. The crystalline phases formed were identified by micro-Raman Spectroscopy; the results indicate the formation of three silver vanadates depending on the silver content. The morphology was observed using scanning electron microscopy, the filmś surface changes from a smooth surface to belts covering the surface and finally Ag nanoparticles are observed at the higher Ag contens. Optical properties determined from UV–vis reveal the presence of the surface plasmon signal in films containing silver. The films were tested in the photocatalytic degradation of Malachite Green dye reaching maximum degradations degrees close to 53% under solar irradiation. Reactive species trapping experiments suggest that O2 − produced by the O2 reduction via the photogenerated electrons drives the photodegradation mechanismCB-168827 CB-240998 F. Gonzalez-Zavala thanks to CONACyT for the PhD and Beca Mixta grants, and also to the SIEA-UAEM for the beca movilidad para estudios avanzados 2016. E. Rodríguez-Castellón thanks to project CTQ2015-68951-C3-3-R of Ministerio de Economía y Competitividad (Spain) and FEDER funds

    High sporulation and overexpression of virulence factors in biofilms and reduced susceptibility to vancomycin and linezolid in recurrent Clostridium [Clostridioides] difficile infection isolates

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    Clostridium [Clostridioides] difficile infection (CDI) is one of the leading causes of diarrhea associated with medical care worldwide, and up to 60% of patients with CDI can develop a recurrent infection (R-CDI). A multi-species microbiota biofilm model of C. difficile was designed to evaluate the differences in the production of biofilms, sporulation, susceptibility to drugs, expression of sporulating (sigH, spo0A), quorum sensing (agrD1, and luxS), and adhesion-associated (slpA and cwp84) pathway genes between selected C. difficile isolates from R-CDI and non-recurrent patients (NR-CDI). We obtained 102 C. difficile isolates from 254 patients with confirmed CDI (66 from NR-CDI and 36 from R-CDI). Most of the isolates were biofilm producers, and most of the strains were ribotype 027 (81.374%, 83/102). Most C. difficile isolates were producers of biofilm (100/102), and most were strongly adherent. Sporulation was higher in the R-CDI than in the NR-CDI isolates (p = 0.015). The isolates from R-CDI patients more frequently demonstrated reduced susceptibility to vancomycin than isolates of NR-CDI patients (27.78% [10/36] and 9.09% [6/66], respectively, p = 0.013). The minimum inhibitory concentrations for vancomycin and linezolid against biofilms (BMIC) were up to 100 times and 20 times higher, respectively, than the corresponding planktonic MICs. Expression of sigH, spo0A, cwp84, and agrD1 was higher in R-CDI than in NR-CDI isolates. Most of the C. difficile isolates were producers of biofilms with no correlation with the ribotype. Sporulation was greater in R-CDI than in NR-CDI isolates in the biofilm model of C. difficile. The R-CDI isolates more frequently demonstrated reduced susceptibility to vancomycin and linezolid than the NR-CDI isolates in both planktonic cells and biofilm isolates. A higher expression of sporulating pathway (sigH, spo0A), quorum sensing (agrD1), and adhesion-associated (cwp84) genes was found in R-CDI than in NR-CDI isolates. All of these factors can have effect on the recurrence of the infection.Peer reviewe

    Proyecto de orientación y mentorización al alumnado de nuevo ingreso en una escuela de ingeniería

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    En este trabajo se presenta un plan de orientación a alumnos noveles en la ETSI de Telecomunicación de la Universidad de Málaga. El programa, que ha pasado por diversas fases en tres años, utiliza la mentoría de alumnos ve-teranos. Pese a la reducida participación, ha posibilitado el desarrollo de diversas actividades formativas y socializantes (para mentores y mentoriza-dos), así como un mejor conocimiento de los problemas que afectan a los alumnos noveles.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Actividad extracurricular en el ámbito de la Ingeniería para la competencia genérica de comunicación escrita

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    El objetivo de este trabajo es describir una actividad formativa extracurricular para la competencia de comunicación escrita, que puede ser fácilmente reproducida en otros centros y universidades. Para ello, en este trabajo se indica el marco en el que se pueden desarrollar las competencias genéricas y se analiza brevemente la actividad propuesta a través de sus resultados de aprendizaje, y cómo estos favorecen e influyen en otras competencias genéricas como la capacidad creativa y el aprendizaje para toda la vida.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Cooperative learning in a Engineering Teaching Framework: an introductory experience to Teamworking

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    Proyecto de Innovación Educativa PIE13-021: Aprendizaje Cooperativo/Colaborativo en el ámbito de la Ingeniería (ACAI)La enseñanza universitaria en el ámbito de la Ingeniería ha estado tradicionalmente orientada al trabajo individual del alumno, lo cual dificulta la adquisición de una de las aptitudes más valoradas en el mercado laboral, como es la competencia de trabajo en grupo. Este trabajo tiene como objetivo fomentar una componente de esta competencia, como es la interacción entre los estudiantes. Para ello se han diseñado y puesto en práctica una serie de actividades docentes en la asignatura “Microcontroladores“, asignatura de 2º curso común a los estudios de Grado en Ingeniería de Sistemas Electrónicos, Sistemas de Telecomunicación, Telemática, Tecnologías de Telecomunicación, y Sonido e Imagen, en la Universidad de Málaga. Asimismo, se ha establecido un conjunto de indicadores que permiten evaluar el grado de consecución de la meta planteada. Los resultados han puesto de manifiesto que la interacción entre los estudiantes se puede fomentar mediante el conjunto de acciones planificadas, aunque las mismas requieren un esfuerzo adicional por parte del profesorado. Finalmente, se han propuesto algunas mejoras en el diseño del procedimiento, para mejorar su eficacia. Este trabajo se enmarca en el proyecto ACAI, cuyo objetivo es implementar un diseño curricular para el desarrollo de la competencia de Trabajo en Grupo. Así, se propone continuar la experiencia aquí presentada fomentando, para los mismos estudiantes, otras componentes de la competencia en asignaturas de 3º y 4º de los grados mencionados.Proyecto de Innovación Educativa PIE13-021, concedido por el Vicerrectorado de Profesorado, Formación, y Coordinación de la Universidad de Málaga

    Phenology and aerial biomass production of the Pithecellobium dulce in a tropical thorny mount area

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    The cover, morphology and aerial production of dry matter (DM) of the specie Pithececellebium dulce (Roxb.) Benth. was evaluated in a xerophyte area. The population density per hectare of trees higher and smaller than 1.5 m was 264 and 1935, equivalent to 22.6 and 2.1% of total botanical community, respectively. Ten adult trees higher than 1.5 m with similar dimension, morphology, vigor and representative of the studied area were selected by systematic sampling and evaluated by destructive and non destructive methods. The averaged architecture for the specie was 4.8, 10.1 cm, 7.3 m’s, 6, and 1463 for number of tree trunks, diameters of tree trunks and crown, branch order, and number of productive branches respectively. The destructive sampling was done monthly during a year. The regression of DM on the number of leaves on productive branches was explained by a cubic function, and that of DM on stem length for a logarithmic one. The estimate of DM by tree was 32.7 ± 0.59 and 21.0 ± 0.59 for the dry and semi dry seasons, respectively, for a total of 14203 ± 312 kg of DM/ha per year. The average of fruits per trees was of 239 « 38. The results show the importance of this species as fodder resource for goat under range systems

    First characterization of toxic alkaloids and volatile organic compounds (VOCs) in the cryptic dendrobatid Silverstoneia punctiventris

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    Background: Poison frogs are known for the outstanding diversity of alkaloid-based chemical defences with promising therapeutic applications. However, current knowledge about chemical defences in Dendrobatoidea superfamily has two sources of bias. First, cryptic, brown-colored species have been neglected in comparison to those conspicuously colored, and second, there has been little interest in characterizing metabolites other than alkaloids mediating defensive functions. In an effort to contribute to fill the gap of knowledge about cryptic species and broadening the spectrum of compounds analyzed we have applied head-space solid phase microextraction coupled to gas chromatography and mass spectrometry (HS-SPME/GC-MS) for extracting amphibian alkaloids and volatile organic compounds (VOCs) from Silverstoneia punctiventris. Results: Using the skin from 8 specimens in 4 biological replicates we have found 33 different compounds. Twenty of them were classified as VOCs into 15 chemical classes including alkanes, alcohols, carbonyl compounds, methylpyridines, benzothiazoles, N-alkylpyrrolidines, pyrazines, and sesquiterpenoids, some of which were previously reported as repellents, defence compounds or defence pheromones in other organisms, and as sex pheromones in a treefrog. Interestingly, six of the remaining compounds were identified as alkaloids previously reported in other toxic/unpalatable dendrobatid frogs. Conclusions: This is the first report of alkaloids and VOCs found in the Silverstoneia genus, which has been assumed for decades as non-chemically defended. This study establishes HS-SPME/GC-MS as a new application for a simultaneous approach to amphibian alkaloids and VOCs in poison frogs while opens up new research questions to assess the co-occurrence of both type of compounds and to investigate the evolutionary significance of a defence gradient that includes olfactory avoidance, unpalatability, and toxicity in dendrobatids. In addition, our results show that amphibian alkaloids could have a dual function (olfactory at distance, taste by contact) never explored before neither in Silverstonaeia nor in any other dendrobatid species.Fil: Gonzalez, Mabel. Universidad de los Andes; ColombiaFil: Palacios Rodriguez, Pablo. Universidad de los Andes; ColombiaFil: Hernandez Restrepo, Jack. Universidad de los Andes; ColombiaFil: González Santoro, Marco. Universidad de los Andes; ColombiaFil: Amézquita, Adolfo. Universidad de los Andes; ColombiaFil: Brunetti, Andrés Eduardo. Universidade de Sao Paulo; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Carazzone, Chiara. Universidad de los Andes; Colombi

    EGF-Coupled Gold Nanoparticles Increase the Expression of CNPase and the Myelin-Associated Proteins MAG, MOG, and MBP in the Septal Nucleus Demyelinated by Cuprizone

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    ARTICULO DE ACCESO ABIERTOCurrent pharmacological therapies against demyelinating diseases are not quite satisfactory to promote remyelination. Epidermal growth factor (EGF) can expand the population of oligodendrocyte precursor cells (OPCs) that may help with the remyelination process, but its delivery into the injured tissue is still a biomedical challenge. Gold nanoparticles (GNPs) may be a useful tool for drug delivery into the brain. To evaluate remyelination in the septal nucleus, we administered intracerebral GNPs coupled with EGF (EGF–GNPs). C57BL6/J mice were demyelinated with 0.4% cuprizone (CPZ) and divided into several groups: Sham, Ctrl, GNPs, EGF, and EGF–GNPs. We evaluated the remyelination process at two time-points: 2 weeks and 3 weeks post-injection (WPI) of each treatment. We used the rotarod for evaluating motor coordination. Then, we did a Western blot analysis myelin-associated proteins: CNPase, MAG, MOG, and MBP. EGF–GNPs increase the expression of CNPase, MAG, and MOG at 2 WPI. At 3 WPI, we found that the EGF–GNPs treatment improves motor coordination and increases MAG, MOG, and MBP. EGF–GNPs enhance the expression of myelin-associated proteins and improve the motor coordination in mice. Thus, EGF-associated GNPs may be a promising pharmacological vehicle for delivering long-lasting drugs into the brain.S/

    Living Situation and Physical Activity in the COVID-19 Pandemic Among Private University Students

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    Physical activity levels among college students in private institutions were significantly altered by the COVID-19 pandemic. With COVID-19’s impact on universities, many students experienced transition, including a change in living situation. Behaviors in college help establish life-long habits that can determine health outcomes, so it’s important to investigate any declines in physical activity observed during the pandemic. PURPOSE: The purpose of this study was to assess differences in physical activity based on living situation among 18- to 25-year-old private university students during the COVID-19 pandemic. METHODS: Adults (n=109) between 18- and 25-years-old in the greater Houston area completed an online survey, which included the International Physical Activity Questionnaire – Short Form. Independent samples T-tests examined MET-minute differences based on living situation. RESULTS: Students living with versus without a parent/guardian attained similar activity levels (t(107) = -.114, p = .910) before the pandemic, but students living with a parent/guardian engaged in significantly less activity (t(107) = 2.04, p = .044) during the pandemic. CONCLUSION: The pandemic presented a strong obstacle to physical activity participation among private university students. Students living with a parent/guardian during this time saw an even more significant decrease in physical activity. Based on these findings, targeted interventions should be made to increase the physical activity of college students during COVID-19, especially for those living at home with a parent or guardian
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