283 research outputs found

    Conformational and thermal characterization of left ventricle remodeling post-myocardial infarction

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    Adverse cardiac remodeling after myocardial infarction (MI) causes impaired ventricular function and heart failure. Histopathological characterization is commonly used to detect the location, size and shape of MI sites. However, the information about chemical composition, physical structure and molecular mobility of peri- and infarct zones post-MI is rather limited. The main objective of this work was to explore the spatiotemporal biochemical and biophysical alterations of key cardiac components post-MI. The FTIR spectra of healthy and remote myocardial tissue shows amides A, I, II and III associated with proteins in freeze-died tissue as major absorptions bands. In infarcted myocardium, the spectrum of these main absorptions was deeply altered. FITR evidenced an increase of the amide A band and the distinct feature of the collagen specific absorption band at 1338cm-1 in the infarct area at 21days post-MI. At 21days post-MI, it also appears an important shift of amide I from 1646cm-1 to 1637cm-1 that suggests the predominance of the triple helical conformation in the proteins. The new spectra bands also indicate an increase in proteoglycans, residues of carbohydrates in proteins and polysaccharides in ischemic areas. Thermal analysis indicates a deep increase of unfreezable water/freezable water in peri- and infarcted tissues. In infarcted tissue is evidenced the impairment of myofibrillar proteins thermal profile and the emergence of a new structure. In conclusion, our results indicate a profound evolution of protein secondary structures in association with collagen deposition and reorganization of water involved in the scar maturation of peri- and infarct zones post-MI

    The RSPH4A Gene in Primary Ciliary Dyskinesia

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    The radial spoke head protein 4 homolog A (RSPH4A) gene is one of more than 50 genes that cause Primary ciliary dyskinesia (PCD), a rare genetic ciliopathy. Genetic mutations in the RSPH4A gene alter an important protein structure involved in ciliary pathogenesis. Radial spoke proteins, such as RSPH4A, have been conserved across multiple species. In humans, ciliary function deficiency caused by RSPH4A pathogenic variants results in a clinical phenotype characterized by recurrent oto-sino-pulmonary infections. More than 30 pathogenic RSPH4A genetic variants have been associated with PCD. In Puerto Rican Hispanics, a founder mutation (RSPH4A (c.921+3_921+6delAAGT (intronic)) has been described. The spectrum of the RSPH4A PCD phenotype does not include laterality defects, which results in a challenging diagnosis. PCD diagnostic tools can combine transmission electron microscopy (TEM), nasal nitric oxide (nNO), High-Speed Video microscopy Analysis (HSVA), and immunofluorescence. The purpose of this review article is to provide a comprehensive overview of current knowledge about the RSPH4A gene in PCD, ranging from basic science to human clinical phenotype

    ‘‘Naked’’ gold nanoparticles supported on HOPG: melanin functionalization and catalytic activity

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    Reductive electrodesorption has been used to produce ‘‘naked’’ gold nanoparticles (AuNPs) 3 nm in size on HOPG from different thiolate-capped AuNPs. The clean AuNPs transform the electrocatalytic inert HOPG into an active surface for hydrogen peroxide electroreduction, causing a lowering of the cathodic overpotential of 0.25 V with respect to the Au(111) surface. Compared to the plain gold substrates, the nanostructures promote only a slight increase in the hydrogen evolution reaction. In a second modification step a 1 nm thick melanin–iron coating is electrochemically formed around the AuNPs. This ultrathin melanin–iron coating largely improves the catalytic activity of the bare AuNPs for both hydrogen peroxide electroreduction and hydrogen evolution reaction. This strategy, which integrates electrochemistry and nanotechnology, can be applied to the preparation of efficient ‘‘naked’’ AuNPs and organic-iron capped AuNPs catalysts.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

    ‘‘Naked’’ gold nanoparticles supported on HOPG: melanin functionalization and catalytic activity

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    Reductive electrodesorption has been used to produce ‘‘naked’’ gold nanoparticles (AuNPs) 3 nm in size on HOPG from different thiolate-capped AuNPs. The clean AuNPs transform the electrocatalytic inert HOPG into an active surface for hydrogen peroxide electroreduction, causing a lowering of the cathodic overpotential of 0.25 V with respect to the Au(111) surface. Compared to the plain gold substrates, the nanostructures promote only a slight increase in the hydrogen evolution reaction. In a second modification step a 1 nm thick melanin–iron coating is electrochemically formed around the AuNPs. This ultrathin melanin–iron coating largely improves the catalytic activity of the bare AuNPs for both hydrogen peroxide electroreduction and hydrogen evolution reaction. This strategy, which integrates electrochemistry and nanotechnology, can be applied to the preparation of efficient ‘‘naked’’ AuNPs and organic-iron capped AuNPs catalysts.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

    MODELO DE ATENCIÓN DEL CÁNCER EN LA INFANCIA Y ADOLESCENCIA

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    La atenciĂłn integral de niños y adolescentes con cĂĄncer es uno de los grandes desafĂ­os para el sistema de salud pĂșblica de nuestros paĂ­ses donde el cĂĄncer infantil representa un problema de salud pĂșblica y un problema social. El cĂĄncer pediĂĄtrico en Paraguay, un paĂ­s de escasos recursos, es un problema social y de salud pĂșblica por las consecuencias que se infringen a los pacientes, sus familias, las comunidades y los sistemas de salud. Un modelo descentralizado con clĂ­nicas mĂĄs cercanas y dedicadas a cuidados primarios y referencias de niños con diagnĂłstico potencial de cĂĄncer mejoraron el acceso a cuidados especializados y seguimiento del cĂĄncer. Estas clĂ­nicas, implementadas dentro de los hospitales regionales de los sistemas nacionales de salud, ofrecen soluciones sostenibles y efectivas para un mejor acceso y seguimiento del cuidado de los niños con cĂĄncer. El anĂĄlisis de los desafĂ­os, el Ă©xito y la rentabilidad de estas clĂ­nicas regionales de cĂĄncer pediĂĄtrico para referencias y seguimiento, permite sugerir un modelo Ăłptimo para tales clĂ­nicas en entornos de bajos ingresos. Este modelo podrĂ­a ser replicado para el cuidado de otras enfermedades y en otros grupos de edad. Presentamos aquĂ­ el resultado de la evaluaciĂłn de los resultados de los pacientes de las cuatro clĂ­nicas regionales desde su implementaciĂłn inicial

    The miniJPAS survey: Optical detection of galaxy clusters with PZWav

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    Galaxy clusters are an essential tool to understand and constrain the cosmological parameters of our Universe. Thanks to its multi-band design, J-PAS offers a unique group and cluster detection window using precise photometric redshifts and sufficient depths. We produce galaxy cluster catalogues from the miniJPAS, which is a pathfinder survey for the wider J-PAS survey, using the PZWav algorithm. Relying only on photometric information, we provide optical mass tracers for the identified clusters, including richness, optical luminosity, and stellar mass. By reanalysing the Chandra mosaic of the AEGIS field, alongside the overlapping XMM-Newton observations, we produce an X-ray catalogue. The analysis reveals the possible presence of structures with masses of 4×1013\times 10^{13} M⊙_\odot at redshift 0.75, highlighting the depth of the survey. Comparing results with those from two other cluster catalogues, provided by AMICO and VT, we find 4343 common clusters with cluster centre offsets of 100±\pm60 kpc and redshift differences below 0.001. We provide a comparison of the cluster catalogues with a catalogue of massive galaxies and report on the significance of cluster selection. In general, we are able to recover approximately 75%\% of the galaxies with M⋆>M^{\star} >2×1011\times 10^{11} M⊙_\odot. This study emphasises the potential of the J-PAS survey and the employed techniques down to the group scales.Comment: 15 pages, 11 figures, 5 tables. Submitted to A&A in December 19, 202

    Enantiopure 4‐oxazolin‐2‐ones and 4‐methylene‐2‐oxazolidinones as chiral building blocks in a divergent asymmetric synthesis of heterocycles

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    En este trabajo se describe la reactividad de las oxazolidin-2-onas en un ambiente quiral obteniĂ©ndose resultados novedosos, los cuales se describen extensamente.Enantiopure 3‐((R)‐ and 3‐((S)‐1‐phenylethyl)‐4‐oxazoline‐2‐ones were evaluated as chiral building blocks for the divergent construction of heterocycles with stereogenic quaternary centers. The N‐(R)‐ or N‐(S)‐1‐phenylethyl group of these compounds proved to be an efficient chiral auxiliary for the asymmetric induction of the 4‐ and 5‐positions of the 4‐oxazolin‐2‐one ring through thermal and MW‐promoted nucleophilic conjugated addition to Michael acceptors and alkyl halides. The resulting adducts were transformed via a cascade process into fused six‐membered carbo‐ and heterocycles. The structure of the reaction products depended on the electrophiles and reaction conditions used. Alternative isomeric 4‐methylene‐2‐oxazolidinones served as chiral precursors for a versatile and divergent approach to highly substituted cyclic carbamates. DFT quantum calculations showed that the formation of bicyclic pyranyl compounds was generated by a diastereoselective concerted hetero‐Diels‐Alder cycloaddition.Instituto PolitĂ©cnico Nacional, Secretaria de InvestigaciĂłn y Estudios Avanzados de la Universidad AutĂłnoma del Estado de MĂ©xico, Universidad de Guanajuato y CONACYT
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