162 research outputs found

    Immobilization of Pyrene-Tagged Palladium and Ruthenium Complexes onto Reduced Graphene Oxide: An Efficient and Highly Recyclable Catalyst for Hydrodefluorinatio

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    The co-immobilization of palladium and ruthenium complexes with pyrene-tagged Nheterocyclic carbene ligands onto reduced grahene oxide allows the formation of a highly efficient catalyst for the hydrodefluorination of a series of fluoroarenes. This procedure constitutes an easy one-pot preparation of materials with homogeneously distributed polymetallic catalysts. The catalytic system can be recycled for up to twelve times without measurable loss of activity. The activity of the catalyst is attributed to the synergistic action of the two metals.Ministerio de Ciencia e Innovación of Spain (CTQ2011- 24055/BQU)

    Enhancement of gold catalytic activity and stability by immobilization on the surface of graphene

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    The catalytic performance of gold complexes is evaluated at the molecular level and when supported onto reduced graphene oxide (rGO). Gold complexes of general formula [(NHC)AuX] catalyse the synthesis of indoles via intramolecular hydroamination reaction of alkynes. The catalytic properties of the molecular gold complexes are highly improved when supported onto graphene. Faster reaction rates and higher catalyst stability are observed for the immobilized gold complexes. The use of graphene as support of molecular complexes has a positive benefit in the catalytic gold properties in terms of activity and stabilityThe authors thank the financial support from MINECO (CTQ2015-69153-C2-2-R), Generalitat Valenciana (AICO/2015/039) and Universitat Jaume I (P1.1B2015-09). D. V-E thanks MINECO for a FPU grant (FPU15/03011

    Catalytic applications of magnetic nanoparticles functionalized using iridium N-heterocyclic carbene complexes

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    synthetic modular methodology allows the preparation of catalytic materials based on magnetic nanoparticles with iridium N-heterocyclic carbene (NHC) complexes. Imidazolium salts containing a ketone/aldehyde as a pendant functional group are the key species prepared. The condensation reaction of the Cp*IrNHC–CHO compound with magnetic nanoparticles containing amine groups on the surface yields the covalent anchoring of the iridium complex to the surface of the magnetite. The catalytic properties have been evaluated in transfer hydrogenation. The iridium complexes and the material are active in the reduction of ketones using isopropanol as the solvent and hydrogen donor. The catalytic results reveal that the catalytic activity of the material and the molecular complex are equivalent. We have not observed any change in activity due to the support. The recyclability properties of the magnetic material have been evaluated. The results show that the catalyst activity is maintained for two runs. This work describes a simple methodology for anchoring molecular complexes on the surface of magnetic nanoparticles.We thank the financial support from the Ministerio de Cienciave Innovación of Spain (CTQ2011-24055/BQU). We thank the ‘Generalitat Valenciana’ for a fellowship (S. Sabater). The authors are grateful to the ‘Serveis Centrals d’Instrumentació Científica (SCIC)’ of the Universitat Jaume I

    Poly-l/dl-lactic acid films functionalized with collagen IV as carrier substrata for corneal epithelial stem cells

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    Limbal epithelial stem cells (LESCs) are responsible for the renewal of corneal epithelium. Cultivated limbal epithelial transplantation is the current treatment of choice for restoring the loss or dysfunction of LESCs. To perform this procedure, a substratum is necessary for in vitro culturing of limbal epithelial cells and their subsequent transplantation onto the ocular surface. In this work, we evaluated poly-L/DL-lactic acid 70:30 (PLA) films functionalized with type IV collagen (col IV) as potential in vitro carrier substrata for LESCs. We first demonstrated that PLA-col IV films were biocompatible and suitable for the proliferation of human corneal epithelial cells. Subsequently, limbal epithelial cell suspensions, isolated from human limbal rings, were cultivated using culture medium that did not contain animal components. The cells adhered significantly faster to PLA-col IV films than to tissue culture plastic (TCP). The mRNA expression levels for the LESC specific markers, K15, P63α and ABCG2 were similar or greater (significantly in the case of K15) in limbal epithelial cells cultured on PLA-col IV films than limbal epithelial cells cultured on TCP. The percentage of cells expressing the corneal (K3, K12) and the LESC (P63α, ABCG2) specific markers was similar for both substrata. These results suggest that the PLA-col IV films promoted LESC attachment and helped to maintain their undifferentiated stem cell phenotype. Consequently, these substrata offer an alternative for the transplantation of limbal cells onto the ocular surface.This work was supported by the Carlos III National Institute of Health, Spain (CIBER-BBN and Spanish Network on Cell Therapy, (TerCel RD12/0019/0036), MINECO/FEDER, EU), and the Castilla y León Regional Government, Spain (Regional Center for Regenerative Medicine and Cell Therapy, SAN673/VA/28/08 and SAN126/VA11/09)

    Genomic analyses of microdissected Hodgkin and Reed-Sternberg cells: mutations in epigenetic regulators and p53 are frequent in refractory classic Hodgkin lymphoma

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    This work was supported by grants from the Plan Nacional de I + D + I cofinanced by the ISCIII-Subdirección General de Evaluación and the Fondo Europeo de Desarrollo Regional (FEDER), PI12/1832, the Spanish Association for Cancer Research (AECC), and Programas para Grupos de Investigación de la Comunidad Autónoma de Madrid (Biomedicina 2017)

    In situ decoration of graphene sheets with gold nanoparticles synthetized by pulsed laser ablation in liquids

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    The demand for nanocomposites of graphene and carbonaceous materials decorated with metallic nanoparticles is increasing on account of their applications in science and technology. Traditionally, the production of graphene-metal assemblies is achieved by the non-environmentally friendly reduction of metallic salts in carbonaceous suspensions. However, precursor residues during nanoparticle growth may reduce their surface activity and promote cross-chemical undesired effects. In this work we present a laser-based alternative to synthesize ligand-free gold nanoparticles that are anchored onto the graphene surface in a single reaction step. Laser radiation is used to generate highly pure nanoparticles from a gold disk surrounded by a graphene oxide suspension. The produced gold nanoparticles are directly immobilized onto the graphene surface. Moreover, the presence of graphene oxide influences the size of the nanoparticles and its interaction with the laser, causes only a slight reduction of the material. This work constitutes a green alternative synthesis of graphene-metal assemblies and a practical methodology that may inspire future developments.The authors thank the financial support from Generalitat Valenciana through the programs PROMETEO-2012-021, AICO/2016/036 and AICO/2015/039, a fellowship (S. Sabater) and a research contract (D. Ventura-Espinosa), the University Jaume I through the projects P1·1B2013-53 and P1.1B2015-09, and the Ministerio de Economía y Competitividad (MINECO) through the projects FIS2013-40666-P and CTQ2015-69153-C2-2-R. The authors are also very grateful to the ‘Serveis Centrals d’Instrumentació Científica (SCIC)’ of the University Jaume I for the use of the femtosecond laser and microscopy facilities. We thank S. Solans for his help with XPS analysis and interpretation. R. Torres-Mendieta gratefully acknowledges the Generalitat Valenciana support for a Santiago Grisolia scholarship GRISOLIA/2013/015

    Consenso sobre la detección y el manejo de la prediabetes. Grupo de trabajo de consensos y guías clínicas de la Sociedad Española de Diabetes

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    En España, según datos del estudio [email protected], un 13,8% de la población adulta padece diabetes y un 14,8% algún tipo de prediabetes (intolerancia a la glucosa, glucemia basal alterada o ambas). Puesto que la detección precoz de la prediabetes puede facilitar la puesta en marcha de medidas terapéuticas que eviten su progresión a diabetes, consideramos que las estrategias de prevención en las consultas de atención primaria y especializada deberían consensuarse. La detección de diabetes y prediabetes mediante un cuestionario específico (test de FINDRISC) y/o la determinación de la glucemia basal en pacientes de riesgo permiten detectar los pacientes con riesgo de desarrollar la enfermedad y es necesario considerar cómo debe ser su manejo clínico. La intervención sobre los estilos de vida puede reducir la progresión a diabetes o hacer retroceder un estado prediabético a la normalidad y es una intervención coste-efectiva. Algunos fármacos, como la metformina, también se han mostrado eficaces en reducir la progresión a diabetes aunque no son superiores a las in tervenciones no farmacológicas. Finalmente, aunque no hay pruebas sólidas que apoyen la eficacia del cribado en términos de morbimortalidad, sí que ha observado una mejora de los factores de riesgo cardiovascular.El Grupo de Trabajo de Consensos y Guías Clínicas de la Sociedad Española de Diabetes (SED) ha elaborado unas recomendaciones que han sido consensuadas con la Sociedad Española de Endocrinología y Nutrición (SEEN), la Sociedad Española de Endocrinología Pediátrica (SEEP), la Sociedad Española de Farmacia Familiar y Comunitaria (SEFAC), la Sociedad Española de Medicina Familiar y Comunitaria (SEMFYC), la Sociedad Española de Médicos Generales (SEMG), la Sociedad Española de Médicos de Atención Primaria (SEMERGEN), la Sociedad Española de Medicina Interna (SEMI), la Asociación de Enfermería Comunitaria (AEC) y la Red de Grupos de Estudio de la Diabetes en Atención Primaria (RedGDPS)

    Urban forest invertebrates : how they shape and respond to the urban environment

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    Invertebrates comprise the most diversified animal group on Earth. Due to their long evolutionary history and small size, invertebrates occupy a remarkable range of ecological niches, and play an important role as "ecosystem engineers" by structuring networks of mutualistic and antagonistic ecological interactions in almost all terrestrial ecosystems. Urban forests provide critical ecosystem services to humans, and, as in other systems, invertebrates are central to structuring and maintaining the functioning of urban forests. Identifying the role of invertebrates in urban forests can help elucidate their importance to practitioners and the public, not only to preserve biodiversity in urban environments, but also to make the public aware of their functional importance in maintaining healthy greenspaces. In this review, we examine the multiple functional roles that invertebrates play in urban forests that contribute to ecosystem service provisioning, including pollination, predation, herbivory, seed and microorganism dispersal and organic matter decomposition, but also those that lead to disservices, primarily from a public health perspective, e.g., transmission of invertebrate-borne diseases. We then identify a number of ecological filters that structure urban forest invertebrate communities, such as changes in habitat structure, increased landscape imperviousness, microclimatic changes and pollution. We also discuss the complexity of ways that forest invertebrates respond to urbanisation, including acclimation, local extinction and evolution. Finally, we present management recommendations to support and conserve viable and diverse urban forest invertebrate populations into the future.Peer reviewe

    16α‐Bromoepiandrosterone as a new candidate for experimental diabetes‐tuberculosis comorbidity treatment

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    Tuberculosis (TB) is the leading cause of death from a single bacterial infectious agent and is one of the most relevant issues of public health. Another pandemic disease is type II diabetes mellitus (T2D) that is estimated to affect half a billion people in the world. T2D is directly associated with obesity and a sedentary lifestyle and is frequently associated with immunosuppression. Immune dysfunction induced by hyperglycemia increases infection frequency and severity. Thus, in developing countries the T2D/TB co-morbidity is frequent and represents one of the most significant challenges for the health-care systems. Several immunoendocrine abnormalities are occurring during the chronic phase of both diseases, such as high extra-adrenal production of active glucocorticoids (GCs) by the activity of 11-β-hydroxysteroid dehydrogenase type 1 (11-βHSD1). 11-βHSD1 catalyzes the conversion of inactive cortisone to active cortisol or corticosterone in lungs and liver, while 11-β-hydroxysteroid dehydrogenase type 2 (11-βHSD2) has the opposite effect. Active GCs have been related to insulin resistance and suppression of Th1 responses, which are deleterious factors in both T2D and TB. The anabolic adrenal hormone dehydroepiandrosterone (DHEA) exerts antagonistic effects on GC signaling in immune cells and metabolic tissues; however, its anabolic effects prohibit its use to treat immunoendocrine diseases. 16α-bromoepiandrosterone (BEA) is a water miscible synthetic sterol related to DHEA that lacks an anabolic effect while amplifying the immune and metabolic properties with important potential therapeutic uses. In this work, we compared the expression of 11-βHSD1 and the therapeutic efficacy of BEA in diabetic mice infected with tuberculosis (TB) (T2D/TB) with respect to non-diabetic TB-infected mice (TB). T2D was induced by feeding mice with a high-fat diet and administering a single low-dose of streptozotocin. After 4 weeks of T2D establishment, mice were infected intratracheally with a high-dose of Mycobacterium tuberculosis strain H37Rv. Then, mice were treated with BEA three times a week by subcutaneous and intratracheal routes. Infection with TB increased the expression of 11-βHSD1 and corticosterone in the lungs and liver of both T2D/TB and TB mice; however, T2D/TB mice developed a more severe lung disease than TB mice. In comparison with untreated animals, BEA decreased GC and 11-βHSD1 expression while increasing 11-βHSD2 expression. These molecular effects of BEA were associated with a reduction in hyperglycemia and liver steatosis, lower lung bacillary loads and pneumonia. These results uphold BEA as a promising effective therapy for the T2D/TB co-morbidity.Fil: López Torres, Manuel Othoniel. Instituto Nacional de la Nutrición Salvador Zubiran; MéxicoFil: Marquina Castillo, Brenda. Instittuto de Ciencias Médicas y Nutrición; MéxicoFil: Ramos Espinosa, Octavio. Instittuto de Ciencias Médicas y Nutrición; MéxicoFil: Mata Espinosa, Dulce. Instittuto de Ciencias Médicas y Nutrición; MéxicoFil: Barrios Payan, Jorge A.. Instittuto de Ciencias Médicas y Nutrición; MéxicoFil: Baay Guzman, Guillermina. Instittuto de Ciencias Médicas y Nutrición; MéxicoFil: Huerta Yepez, Sara. Instittuto de Ciencias Médicas y Nutrición; MéxicoFil: Bini, Estela Isabel. Instittuto de Ciencias Médicas y Nutrición; MéxicoFil: Torre Villalvazo, Ivan. Instittuto de Ciencias Médicas y Nutrición; MéxicoFil: Torres, Nimbe. Instittuto de Ciencias Médicas y Nutrición; MéxicoFil: Tovar, Armando. Instittuto de Ciencias Médicas y Nutrición; MéxicoFil: Chamberlin, William. No especifíca;Fil: Ge, Yu. No especifíca;Fil: Carranza, Maria Andrea. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto Alberto C. Taquini de Investigaciones En Medicina Traslacional. - Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Cardiologicas "prof. Dr. Alberto C. Taquini". Instituto Alberto C. Taquini de Investigaciones En Medicina Traslacional.; ArgentinaFil: Hernández Pando, Rogelio. Instituto Nacional de Ciencias Medicas y Nutricion; Méxic

    Passivation layers for nanostructured photoanodes : Ultra-thin oxides on InGaN nanowires

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    An experimental strategy for systematically assessing the influence of surface passivation layers on the photocatalytic properties of nanowire photoanodes by combining photocurrent analysis, photoluminescence spectroscopy and high resolution transmission electron microscopy with a systematic variation of sample structure and the surrounding electrolyte is demonstrated. Following this approach we can separate the impact on recombination and transport processes of photogenerated carriers. We apply this strategy to analyze the influence of ultra-thin TiO, CeO and AlO coatings deposited by atomic layer deposition on the photoelectrochemical performance of InGaN/GaN nanowire (NW) photoelectrodes. The passivation of surface states results in an increase of the anodic photocurrent (PC) by a factor of 2.5 for the deposition of 5 nm TiO. In contrast, the PC is reduced for CeO- and AlO-coated NWs due to enhanced defect recombination in the passivation layer or increased band discontinuities. Furthermore, photoelectrochemical oxidation of the InGaN/GaN NW photoelectrode is attenuated by the TiO layer and completely suppressed for a layer thickness of 7 nm or more. Due to efficient charge transfer from the InGaN NW core a stable TiO-covered photoanode with visible light excitation is realized
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