283 research outputs found
Conformational and thermal characterization of left ventricle remodeling post-myocardial infarction
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
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
ââNakedââ gold nanoparticles supported on HOPG: melanin functionalization and catalytic activity
Reductive electrodesorption has been used to produce âânakedââ 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 melaninâiron coating is electrochemically formed around the AuNPs. This ultrathin melaninâiron 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 âânakedââ AuNPs and organic-iron capped AuNPs catalysts.Instituto de Investigaciones FisicoquĂmicas TeĂłricas y Aplicada
ââNakedââ gold nanoparticles supported on HOPG: melanin functionalization and catalytic activity
Reductive electrodesorption has been used to produce âânakedââ 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 melaninâiron coating is electrochemically formed around the AuNPs. This ultrathin melaninâiron 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 âânakedââ AuNPs and organic-iron capped AuNPs catalysts.Instituto de Investigaciones FisicoquĂmicas TeĂłricas y Aplicada
MODELO DE ATENCIĂN DEL CĂNCER EN LA INFANCIA Y ADOLESCENCIA
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
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 M 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 common clusters with cluster centre
offsets of 10060 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 2 M. 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
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Projected sensitivity of the LUX-ZEPLIN experiment to the 0ÎœÎČÎČ decay of Xe 136
The LUX-ZEPLIN (LZ) experiment will enable a neutrinoless double ÎČ decay search in parallel to the main science goal of discovering dark matter particle interactions. We report the expected LZ sensitivity to Xe136 neutrinoless double ÎČ decay, taking advantage of the significant (>600 kg) Xe136 mass contained within the active volume of LZ without isotopic enrichment. After 1000 live-days, the median exclusion sensitivity to the half-life of Xe136 is projected to be 1.06Ă1026 years (90% confidence level), similar to existing constraints. We also report the expected sensitivity of a possible subsequent dedicated exposure using 90% enrichment with Xe136 at 1.06Ă1027 years
Enantiopure 4âoxazolinâ2âones and 4âmethyleneâ2âoxazolidinones as chiral building blocks in a divergent asymmetric synthesis of heterocycles
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 3â((R)â and 3â((S)â1âphenylethyl)â4âoxazolineâ2âones were evaluated as chiral building blocks for the divergent construction of heterocycles with stereogenic quaternary centers. The Nâ(R)â or Nâ(S)â1âphenylethyl group of these compounds proved to be an efficient chiral auxiliary for the asymmetric induction of the 4â and 5âpositions of the 4âoxazolinâ2âone ring through thermal and MWâpromoted nucleophilic conjugated addition to Michael acceptors and alkyl halides. The resulting adducts were transformed via a cascade
process into fused sixâmembered carboâ and heterocycles. The structure of the reaction products depended on the electrophiles and reaction conditions used. Alternative isomeric 4âmethyleneâ2âoxazolidinones 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 heteroâDielsâAlder 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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Projected WIMP sensitivity of the LUX-ZEPLIN dark matter experiment
LUX-ZEPLIN (LZ) is a next-generation dark matter direct detection experiment that will operate 4850 feet underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. Using a two-phase xenon detector with an active mass of 7 tonnes, LZ will search primarily for low-energy interactions with weakly interacting massive particles (WIMPs), which are hypothesized to make up the dark matter in our galactic halo. In this paper, the projected WIMP sensitivity of LZ is presented based on the latest background estimates and simulations of the detector. For a 1000 live day run using a 5.6-tonne fiducial mass, LZ is projected to exclude at 90% confidence level spin-independent WIMP-nucleon cross sections above 1.4Ă10-48 cm2 for a 40 GeV/c2 mass WIMP. Additionally, a 5Ï discovery potential is projected, reaching cross sections below the exclusion limits of recent experiments. For spin-dependent WIMP-neutron(-proton) scattering, a sensitivity of 2.3Ă10-43 cm2 (7.1Ă10-42 cm2) for a 40 GeV/c2 mass WIMP is expected. With underground installation well underway, LZ is on track for commissioning at SURF in 2020
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