349 research outputs found

    Synthesis and Characterization of Reduced Graphene Oxide/ Polyaniline/Au Nanoparticles Hybrid Material for Energy Applications

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    In this work, synthesis and characterization of reduced graphene oxide/polyaniline/Au nanoparticles (GO/PANI/NpAu) as a hybrid capacitor are presented. Graphite oxide (GO) was synthesized by a modified Hummer’s method. Polyaniline was synthesized by chemical polymerization, and Au nanoparticles (NpAu) were added afterward. Fabrication of the electrodes consisted on the hybrid materials being deposited on carbon cloth electrodes. The chemical and structural properties of the electrode were characterized by high-resolution scanning electron microscopy (HRSEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (X-R), and Raman spectroscopy; the results confirm the graphene reduction, the covalent functionalization, and formation of nanocomposites and also show the polyaniline grafted graphene. The performance and evaluation of the electrodes based on grapheme oxide (GO), polyaniline (PANI), GO-PANI, and GO/PANI/NpAu nanocomposites over carbon cloth, stainless steel, and copper have been obtained in 1 M H2SO4 solution, using electrochemical techniques namely: cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). They showed that GO/PANI/NpAu gave higher specific capacitance (SC) and energy values than PANI, and GO/PANI, in the order of 160 F/g. The present study introduces new hybrid material for energy applications, from the evaluation of their electrical contributions

    Pretratamiento con hialuronidasa mejora la tinción de colágeno en notocorda de esturión

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    Objective: The current study aimed to design a histological method to determine the presence and organization of the collagen network in sturgeon notochord. Methods: Serial sections of sturgeon notochord (Acipenser naccarii) were used and assigned to two different experimental groups: Hyaluronidase pre-treatment (HP) in an alcohol acid solution (1% HCl in 70% alcohol solution) for 15 min and hyaluronidase solution in a 2 µg/ ml concentration (pre-heated at 37º C), and control (CTR) group, without pre-treatment. Then, the ECM was assessed by two histochemical methods: Picrosirius Red (PR) staining for 30 min with Sirius red (0.1% of Sirius red in saturated aqueous picric acid), for collagen bundle staining, and Alcian Blue (AB) staining for glycosaminoglycans detection. Results: Samples analyzed in this study showed positive histochemical reaction for collagen fibers in both experimental groups. Referring to PR staining, the CTR group presented a larger and homogeneous reaction was observed in the entire samples, whereas HP group presented a more definite and intense pattern of collagen network. Also, this more intense signal in HP group matched with an increase of birefringence in polarized microscopy images of PR. However, HP group showed a lower intense and more heterogeneous signal when was compared with CTR group in AB staining. Conclusion: Using a simple histological example, our study illustrates the capability of a hyaluronidase pre-treatment to enhance picrosirius red staining in sturgeon notochord trough light and polarized microscopy.Objetivo: El presente estudio tiene por objetivo diseñar un método histológico para determinar la presencia y organización de la red de colágeno en la notocorda del esturión. Métodos: Secciones seriada de la notocorda de esturión (Acipenser naccarii) fueron utilizadas y se asignaron a dos grupos experimentales diferentes: pretratamiento de hialuronidasa (HP) en una solución de alcohol ácido (HCl al 1% en solución de alcohol al 70%) durante 15 minutos y posteriormente a una solución de hialuronidasa en una concentración de 2 μg / ml (precalentada a 37º C) y grupo de control (CTR), sin tratamiento previo. Luego, la ECM se evaluó mediante dos métodos histoquímicos: tinción Picrosirius Red (PR) durante 30 minutos con rojo Sirio (0,1% de rojo Sirio en una solución saturada de ácido pícrico), para la tinción de colágeno; y tinción con Alcian Blue (AB) para detección de glicosaminoglicanos. Resultados: Las muestras analizadas en este estudio mostraron una reacción histoquímica positiva para las fibras de colágeno en ambos grupos experimentales. Con respecto a la tinción PR, el grupo CTR presentó una reacción mayor y más homogénea en toda la superficie de las muestras, mientras que el grupo HP presentó un patrón red de colágeno más definido e intenso. Además, esta señal más intensa en el grupo HP coincidió con un aumento de la birrefringencia en las imágenes de microscopía polarizada de PR. Sin embargo, el grupo HP mostró una señal menos intensa y más heterogénea cuando se comparó con el grupo CTR en la tinción AB. Conclusión: Utilizando un ejemplo histológico simple, nuestro estudio ilustra la capacidad de un pretratamiento de hialuronidasa para mejorar la tinción de picrosirius en la notocorda del esturión a través de la luz y la microscopía polarizada

    Effects of the Addition of Ortho

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    The synthetic tetrapyrrole macrocycles, such as porphyrins (H2P) and phthalocyanines (H2Pc), exhibit interesting physicochemical properties suitable to be used in modern technology. For many applications, those species should be trapped or fixed inside graphite, hydrotalcites, silica, TiO2, or polymers. Methodologies for the optimization of the properties of porphyrins, trapped or fixed inside polymers, have been barely developed. Our research works in the development of methodologies for the optimization of incorporation and display of properties of tetrapyrrole macrocycles inside inorganic, polymeric, or hybrid networks. This paper shows some results about the effect of the spatial disposition of the amine (–NH2) groups attached on the periphery of substituted tetraphenylporphyrins, on the Nylon 66 structure and on the display of the physicochemical properties of the trapped macrocycles. Nylon 66 was synthesized from adipoyl chloride and hexamethylenediamine in presence of tetraphenylporphyrins substituted with –NH2 groups localized at the ortho- or para-positions of the phenyls. Cobalt complexes formation was used to quantify the amount of porphyrins in the polymer fibers. Characterization results show that the spatial position of amine groups of the porphyrins has important structural and textural effect on the Nylon 66 fibers and on the fluorescence of the porphyrins integrated into the fibers

    Potential Impacts in the Gilthead Seabream Larviculture by Nodavirus

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    The nervous necrosis virus (NNV) leads to viral encephalopathy and retinopathy (VER) disease in more than 170 fish species, mainly from marine habitats. It replicates in the central nervous tissues, reaching up to 100% mortalities after a few days of infection, mainly in the larvae and juvenile stages. This is continuously spreading and affecting more species, both wild and cultured, posing a risk to the development of the aquaculture industry. In the Mediterranean Sea, it mainly affects European sea bass (Dicentrarchus labrax) and some grouper species (Epinephelus spp.). Interestingly, in the gilthead seabream (Sparus aurata), typically resistant to common NNV strains, great mortalities in hatcheries associated with typical clinical signs of VER have been confirmed to be caused by RGNNV/SJNNV reassortants. Thus, we have evaluated the susceptibility of seabream larvae to either RGNNV/SJNNV or SJNNV/RGNNV reassortants, as well as the larval immunity. Based on our results we can conclude that: (i) gilthead seabream larvae are susceptible to infection with both NNV reassortant genotypes, but mainly to RGNNV/SJNNV; (ii) virus replicated and infective particles were isolated; (iii) larval immunity was correlated with larval survival; and (iv) larval resistance and immunity were correlated with age of the larvae. Further investigations should be carried out to ascertain the risks of these new pathogens to Mediterranean larviculture

    Heterogeneity of Melanoma Cell Responses to Sleep Apnea-Derived Plasma Exosomes and to Intermittent Hypoxia

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    Obstructive sleep apnea (OSA) is associated with increased cutaneous melanoma incidence and adverse outcomes. Exosomes are secreted by most cells, and play a role in OSA-associated tumor progression and metastasis. We aimed to study the effects of plasma exosomes from OSA patients before and after adherent treatment with continuous positive airway pressure (CPAP) on melanoma cells lines, and also to identify exosomal miRNAs from melanoma cells exposed to intermittent hypoxia (IH) or normoxia. Plasma-derived exosomes were isolated from moderate-tosevere OSA patients before (V1) and after (V2) adherent CPAP treatment for one year. Exosomes were co-incubated with three3 different melanoma cell lines (CRL 1424; CRL 1619; CRL 1675) that are characterized by genotypes involving different mutations in BRAF, STK11, CDKN2A, and PTEN genes to assess the effect of exosomes on cell proliferation and migration, as well as on pAMK activity in the presence or absence of a chemical activator. Subsequently, CRL-1424 and CRL-1675 cells were exposed to intermittent hypoxia (IH) and normoxia, and exosomal miRNAs were identified followed by GO and KEG pathways and gene networks. The exosomes from these IH-exposed melanoma cells were also administered to THP1 macrophages to examine changes in M1 and M2 polarity markers. Plasma exosomes from V1 increased CRL-1424 melanoma cell proliferation and migration compared to V2, but not the other two cell lines. Exposure to CRL-1424 exosomes reduced pAMPK/tAMPK in V1 compared to V2, and treatment with AMPK activator reversed the effects. Unique exosomal miRNAs profiles were identified for CRL-1424 and CRL-1675 in IH compared to normoxia, with six miRNAs being regulated and several KEGG pathways were identified. Two M1 markers (CXCL10 and IL6) were significantly increased in monocytes when treated with exosomes from IH-exposed CRL-1424 and CRL-1625 cells. Our findings suggest that exosomes from untreated OSA patients increase CRL-1424 melanoma malignant properties, an effect that is not observed in two other melanoma cell lines. Exosomal cargo from CRL-1424 cells showed a unique miRNA signature compared to CRL-1675 cells after IH exposures, suggesting that melanoma cells are differentially susceptible to IH, even if they retain similar effects on immune cell polarity. It is postulated that mutations in STK-11 gene encoding for the serine/threonine kinase family that acts as a tumor suppressor may underlie susceptibility to IH-induced metabolic dysfunction, as illustrated by CRL1424 cells

    Producción científica Iberoamericana sobre TIC en el contexto educativo

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    ICT in the educational context can be seen as information transmitting resources that link the teacher and the student in the improvement of teaching-learning adapted to the needs and characteristics of each subject. From this perspective, we seek to describe the state of Iberoamerican scientific production on the inclusion of ICT in the educational discipline in the period 2010 to 2020, based on a retrospective descriptive analysis of publications collected in journals indexed in Scopus. A total of n=1976 contributions were collected. It was found that production increased by 8.51%. Spain is the Iberoamerican country that contributes with the highest scientific production, authors with Iberoamerican affiliation usually publish through conference articles, highlighting ACM International Conference Proceeding Series. In front of an analysis of maturity of knowledge we are facing a development of scientific production in process of growth.Las TIC en el contexto educativo pueden verse conocidos como recursos transmisores de información que vincula al docente y al estudiante en la mejora de la enseñanza - aprendizaje adaptado a las necesidades y características de cada sujeto. Desde esta perspectiva se busca describir el estado de la producción científica Iberoamericana sobre la inclusión de las TIC en la disciplina educativa en el periodo 2010 al 2020. El estudio se basa en el análisis descriptivo retrospectivo de publicaciones recopiladas en revistas indizadas en Scopus. Se recolectó un total de n=1976 contribuciones. Se encontró que la producción aumentó en un 8,51%. España es el país Iberoamericano que contribuye con mayor producción científica, los autores con afiliación Iberoamericana suelen publicar a través de Artículos de conferencia, destacando ACM International Conference Proceeding Series. Frente a un análisis de madurez de conocimiento estamos ante un desarrollo de producción científica en proceso de crecimiento

    Producción científica Iberoamericana sobre TIC en el contexto educativo

    Get PDF
    ICT in the educational context can be seen as information transmitting resources that link the teacher and the student in the improvement of teaching-learning adapted to the needs and characteristics of each subject. From this perspective, we seek to describe the state of Iberoamerican scientific production on the inclusion of ICT in the educational discipline in the period 2010 to 2020, based on a retrospective descriptive analysis of publications collected in journals indexed in Scopus. A total of n=1976 contributions were collected. It was found that production increased by 8.51%. Spain is the Iberoamerican country that contributes with the highest scientific production, authors with Iberoamerican affiliation usually publish through conference articles, highlighting ACM International Conference Proceeding Series. In front of an analysis of maturity of knowledge we are facing a development of scientific production in process of growth.Las TIC en el contexto educativo pueden verse conocidos como recursos transmisores de información que vincula al docente y al estudiante en la mejora de la enseñanza - aprendizaje adaptado a las necesidades y características de cada sujeto. Desde esta perspectiva se busca describir el estado de la producción científica Iberoamericana sobre la inclusión de las TIC en la disciplina educativa en el periodo 2010 al 2020. El estudio se basa en el análisis descriptivo retrospectivo de publicaciones recopiladas en revistas indizadas en Scopus. Se recolectó un total de n=1976 contribuciones. Se encontró que la producción aumentó en un 8,51%. España es el país Iberoamericano que contribuye con mayor producción científica, los autores con afiliación Iberoamericana suelen publicar a través de Artículos de conferencia, destacando ACM International Conference Proceeding Series. Frente a un análisis de madurez de conocimiento estamos ante un desarrollo de producción científica en proceso de crecimiento

    Producción científica Iberoamericana sobre TIC en el contexto educativo

    Get PDF
    ICT in the educational context can be seen as information transmitting resources that link the teacher and the student in the improvement of teaching-learning adapted to the needs and characteristics of each subject. From this perspective, we seek to describe the state of Iberoamerican scientific production on the inclusion of ICT in the educational discipline in the period 2010 to 2020, based on a retrospective descriptive analysis of publications collected in journals indexed in Scopus. A total of n=1976 contributions were collected. It was found that production increased by 8.51%. Spain is the Iberoamerican country that contributes with the highest scientific production, authors with Iberoamerican affiliation usually publish through conference articles, highlighting ACM International Conference Proceeding Series. In front of an analysis of maturity of knowledge we are facing a development of scientific production in process of growth.Las TIC en el contexto educativo pueden verse conocidos como recursos transmisores de información que vincula al docente y al estudiante en la mejora de la enseñanza - aprendizaje adaptado a las necesidades y características de cada sujeto. Desde esta perspectiva se busca describir el estado de la producción científica Iberoamericana sobre la inclusión de las TIC en la disciplina educativa en el periodo 2010 al 2020. El estudio se basa en el análisis descriptivo retrospectivo de publicaciones recopiladas en revistas indizadas en Scopus. Se recolectó un total de n=1976 contribuciones. Se encontró que la producción aumentó en un 8,51%. España es el país Iberoamericano que contribuye con mayor producción científica, los autores con afiliación Iberoamericana suelen publicar a través de Artículos de conferencia, destacando ACM International Conference Proceeding Series. Frente a un análisis de madurez de conocimiento estamos ante un desarrollo de producción científica en proceso de crecimiento

    A unified vegetation index for quantifying the terrestrial biosphere

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    [EN] Empirical vegetation indices derived from spectral reflectance data are widely used in remote sensing of the biosphere, as they represent robust proxies for canopy structure, leaf pigment content, and, subsequently, plant photosynthetic potential. Here, we generalize the broad family of commonly used vegetation indices by exploiting all higher-order relations between the spectral channels involved. This results in a higher sensitivity to vegetation biophysical and physiological parameters. The presented nonlinear generalization of the celebrated normalized difference vegetation index (NDVI) consistently improves accuracy in monitoring key parameters, such as leaf area index, gross primary productivity, and sun-induced chlorophyll fluorescence. Results suggest that the statistical approach maximally exploits the spectral information and addresses long-standing problems in satellite Earth Observation of the terrestrial biosphere. The nonlinear NDVI will allow more accurate measures of terrestrial carbon source/sink dynamics and potentials for stabilizing atmospheric CO2 and mitigating global climate change.G.C.-V. was supported by the European Research Council (ERC) under the ERC Consolidator Grant 2014 project SEDAL (647423). M.C.-T. and F.J.G.-H. were supported by the EUMETSAT Satellite Application Facility on Land Surface Analysis (LSA-SAF). SR research was financially supported by the NASA Earth Observing System MODIS project (grant NNX08AG87A). J.A.G. acknowledges the support of NASA ABoVE award number NNX15AT78A. S.W. acknowledges funding from the Emmy Noether Programme (GlobFluo project) of the German Research Foundation (GU 1276/1-1) as well as funding from the European Union's Horizon 2020 research and innovation program under grant agreement 776186 (CHE project) and agreement 776810 (VERIFY project).Camps-Valls, G.; Campos-Taberner, M.; Moreno-Martínez, Á.; Walther, S.; Duveiller, G.; Cescatti, A.; Mahecha, MD.... (2021). A unified vegetation index for quantifying the terrestrial biosphere. Science Advances. 7(9):1-11. https://doi.org/10.1126/sciadv.abc74471117
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