40 research outputs found

    Novel Engineered Nanostructured Complex Oxide for High Temperature Thermoelectric Power Generation

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    Thermoelectric power generators are a promising technology that can produce electrical power directly from waste heat emitted in energy production and consumption systems. The essential component of thermoelectric generators is the thermoelectric material which performs the energy conversion process. In order to make thermoelectric devices to be considered a significant contributor to US energy infrastructure, it is essential first to foster improvements in high performance thermoelectric materials. They must possess not only a high conversion efficiency, but also need be composed of nontoxic and abundantly available elemental materials having high chemical stability in air up to 800-1000 K. In comparison with the conventional thermoelectric materials (intermetallic compounds); the layered oxide materials, such as the newly developed nontoxic p-type Ca3Co4O9, are particularly promising for thermoelectric applications because of their high stability at high temperatures in air.;In recent years, the layered cobalt oxide Ca3Co4O 9 system has gained great attention due to its outstanding thermoelectric performance (ZT=0.83 at 973 K) for the single crystal. Single crystals, however, are too small and expensive for practical applications. The current challenge for developing oxide thermoelectric materials is to improve the conversion efficiency of the polycrystalline Ca3Co 4O9 ceramic, which is currently lower than that of the conventional thermoelectric materials. The distinctive objective in this research is to optimize the energy inter-conversion properties of p-type Ca3Co 4O9 ceramic, through nano-structure engineering approaches. Novel methods of introducing the appropriate dopants and other nano-structures into the oxide were investigated, and the effect of dopants and nano-structure engineering on the thermoelectric performance of the Ca3Co 4O9 system was evaluated. The above study will be instrumental for fabricating polycrystalline Ca3Co4O9 with optimized microstructure and enhanced thermoelectric properties

    The high-energy emission from HD 93129A near periastron

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    We conducted an observational campaign towards one of the most massive and luminous colliding wind binaries in the Galaxy, HD~93129A, close to its periastron passage in 2018. During this time the source was predicted to be in its maximum of high-energy emission. Here we present our data analysis from the X-ray satellites \textit{Chandra} and \textit{NuSTAR} and the γ-ray satellite \textit{AGILE}. High-energy emission coincident with HD~93129A was detected in the X-ray band up to ∼18~keV, whereas in the γ-ray band only upper limits were obtained. We interpret the derived fluxes using a non-thermal radiative model for the wind-collision region. We establish a conservative upper limit for the fraction of the wind kinetic power that is converted into relativistic electron acceleration, fNT,e0.3~G. We also argue a putative interpretation of the emission from which we estimate fNT,e≈0.006 and BWCR≈0.5~G. We conclude that multi-wavelength, dedicated observing campaigns during carefully selected epochs are a powerful tool for characterising the relativistic particle content and magnetic field intensity in colliding wind binaries

    New insights into the genetic etiology of Alzheimer's disease and related dementias

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    Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

    Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

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    Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

    Multiancestry analysis of the HLA locus in Alzheimer’s and Parkinson’s diseases uncovers a shared adaptive immune response mediated by HLA-DRB1*04 subtypes

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    Across multiancestry groups, we analyzed Human Leukocyte Antigen (HLA) associations in over 176,000 individuals with Parkinson’s disease (PD) and Alzheimer’s disease (AD) versus controls. We demonstrate that the two diseases share the same protective association at the HLA locus. HLA-specific fine-mapping showed that hierarchical protective effects of HLA-DRB1*04 subtypes best accounted for the association, strongest with HLA-DRB1*04:04 and HLA-DRB1*04:07, and intermediary with HLA-DRB1*04:01 and HLA-DRB1*04:03. The same signal was associated with decreased neurofibrillary tangles in postmortem brains and was associated with reduced tau levels in cerebrospinal fluid and to a lower extent with increased Aβ42. Protective HLA-DRB1*04 subtypes strongly bound the aggregation-prone tau PHF6 sequence, however only when acetylated at a lysine (K311), a common posttranslational modification central to tau aggregation. An HLA-DRB1*04-mediated adaptive immune response decreases PD and AD risks, potentially by acting against tau, offering the possibility of therapeutic avenues

    Physicochemical parameters and sensory properties of honeys from Buenos Aires region

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    The physicochemical parameters (moisture, hydroxymethyl furfural, colour, electrical conductivity, free acidity, glucose, fructose and sucrose) and the sensory properties(aroma, taste, appeareance, texture) were determined in honeys from apiaries of the agricultural, hills and meadow zones of the south east region of Buenos Aires province (Argentina). The analysis of variance showed significant differences among zones in the mean value of hydroximethyl furfural, colour, electrical conductivity and sucrose content. The principal component analysis explained the 70% of the variance among samples with the first two principal components in both cases. The cluster analysis and linear discriminant analysis showed that samples were grouped in relation to the sampling region coinciding with the results of the principal component analysis. Results suggest that could be possible to classify honeys according to the geographic origin based on the physicochemical parameters; however, the sensory properties were not good predictors.Fil: Silvano, Maria F.. Instituto Nacional de Tecnología Agropecuaria; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Varela, Maria S.. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Palacio, Maria Alejandra. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Ruffinengo, Sergio Roberto. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Yamul, Diego Karim. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentin

    Asociación de parásitos intestinales con síndrome anémico en niños escolares: Una revisión sistemática de la literatura

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    Introducción: Las parasitosis intestinales y la anemia son un problema de salud pública mundial. Estos parásitos tienen tropismo hacia el intestino delgado, afectan la absorción de micronutrientes durante la eritropoyesis, produciendo la aparición de un síndrome anémico por un recuento bajo de glóbulos rojos y déficit de hemoglobina. Objetivo: Establecer la asociación de la infección por parásitos intestinales y síndrome anémico en niños en edad escolar. Materiales y métodos: Búsqueda sistemática de literatura publicada entre 2010-2021 sobre asociación entre infección por parásitos intestinales y síndrome anémico en escolares. Resultados: Se identificó 1151 publicaciones, al aplicar los criterios de inclusión y exclusión, se redujeron a 33, encontrándose 9 agentes asociados a anemia, siendo A. lumbricoides (27,27%), A. duodenalis y T. trichiura los helmintos más prevalentes, y G. duodenalis (6,06%) el protozoario más común. El 39,39% de los estudios incluyó ambos agentes. África (21), Asia (6), Sudamérica (5) y Centroamérica (1) tienen la mayoría de publicaciones. Se observa asociación significativa entre infección parasitaria y la anemia IC=95%. Conclusión: La evidencia demuestra alta prevalencia de anemias carenciales de tipo ferropénica y megaloblástica, con asociación significativa entre un mayor porcentaje de infecciones por helmintos y síndrome anémico, en comparación con infecciones por protozoos
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