2,201 research outputs found

    CO-PrOx over nano-Au/TiO2: Monolithic catalyst performance and empirical kinetic model fitting

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    In this work, the performance of ceramic monoliths washcoated with Au/TiO2 is studied on CO preferential oxidation (CO-PrOx) reaction in H2-rich environments under a wide range of operating conditions of practical interest. The parameter estimation of a nonlinear kinetic empirical model representing this system is made via genetic algorithms by fitting the model predictions against our laboratory observations. Parameter uncertainty leading to inaccurate predictions is often present when kinetic models with nonlinear rate equations are considered. Here, after the fitting was concluded, a statistical study was conducted to determine the accuracy of the parameter estimation. Activation energies of ca. 30 kJ/mol and 55 kJ/mol were adjusted for CO and H2 oxidations, respectively. The catalyst showed appropriate activity and selectivity values on the CO oxidation on a H2-rich environment. After ca. 45 h on stream the catalyst showed no deactivation. Results show that the model is suitable for reproducing the behavior of the CO-PrOx reactions and it can be used in the design of reactors for hydrogen purification.Peer ReviewedPostprint (author's final draft

    Inundaciones y cambio climático

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    Las inundaciones de los ríos han sucedido de forma tradicional en numerosos ríos de la Península Ibérica, aportando grandes beneficios en la agricultura y en la disponibilidad de recursos hídricos, pero en la historia más reciente han originado graves daños en personas y bienes haciendo que hoy día predomine una percepción de las inundaciones como “catástrofes”. En el origen del incremento de la frecuencia de las inundaciones hay que mencionar la intensificación del uso del territorio, sellando y compactando los suelos haciendo que aumenten las escorrentías rápidas, y la alteración hidromorfológica de los ríos, concentrando las aguas y favoreciendo la ocurrencia de avenidas y desbordamientos. En el incremento exponencial de las pérdidas que las inundaciones han originado en los últimos años hay que referirse a la intensa ocupación de las riberas de los ríos y sus llanuras de inundación por personas y actividades económicas, con un desarrollo en dichas zonas no compatible con la dinámica fluvial. El cambio climático es considerado un factor de riesgo adicional muy variable según las regiones, y la estimación de sus efectos sobre las inundaciones presenta todavía numerosas incertidumbres. Atendiendo a ello se revisan algunos estudios e informes relacionados con el fenómeno de las inundaciones y su posible relación con el cambio climático, y se propone la restauración de los sistemas fluviales y la restricción de usos en las zonas inundables como estrategias más acertadas para hacer frente a la mencionada problemática de las inundaciones y a la incertidumbre creada con el cambio climático. El análisis de los sucesivos paradigmas históricos planteados por el hombre frente a las inundaciones de los ríos pone en evidencia el interés de cambiar unas estrategias de “defensa” en contra de ellas, tratando de evitar que ocurran, por otras de “convivencia” con las mismas gestionando de la forma más apropiada el riesgo de los daños que pueden generar, atendiendo al espíritu de las Directivas europeas Marco del Agua y de evaluación y gestión del riesgo de la inundación

    Infection of laboratory-colonized Anopheles darlingi mosquitoes by Plasmodium vivax.

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    Anopheles darlingi Root is the most important malaria vector in the Amazonia region of South America. However, continuous propagation of An. darlingi in the laboratory has been elusive, limiting entomological, genetic/genomic, and vector-pathogen interaction studies of this mosquito species. Here, we report the establishment of an An. darlingi colony derived from wild-caught mosquitoes obtained in the northeastern Peruvian Amazon region of Iquitos in the Loreto Department. We show that the numbers of eggs, larvae, pupae, and adults continue to rise at least to the F6 generation. Comparison of feeding Plasmodium vivax ex vivo of F4 and F5 to F1 generation mosquitoes showed the comparable presence of oocysts and sporozoites, with numbers that corresponded to blood-stage asexual parasitemia and gametocytemia, confirming P. vivax vectorial capacity in the colonized mosquitoes. These results provide new avenues for research on An. darlingi biology and study of An. darlingi-Plasmodium interactions

    A Network Analysis of the Five Facets Mindfulness Questionnaire (FFMQ)

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    Objectives: The Five Facet Mindfulness Questionnaire (FFMQ) is a popular self-report instrument for mindfulness assessment. However, several studies report mixed evidence regarding its reliability and validity. While recent replication studies have shown several issues regarding its latent structure, first-order facets seemed to replicate successfully. This study proposes an exploratory approach to these facets on an item level in one sample, with cross-validation in another sample. Methods: Using a snowball sampling, 1008 participants were recruited in the first sample. Psychometric networks were applied to explore relations between items and item clusters. We compared these exploratory latent variable proposals with previous literature. A second sample of 1210 participants was collected from an FFMQ validation study, and confirmatory factor analyses were applied to cross-validate findings on the first sample. Results: The FFMQ showed a positively correlated network. Exploratory analyses suggested the 5-facet structure as stable with alternatives of 4-facet (merging Observe and Non-Judging) and 6-facet (splitting Acting with Awareness in two) solutions. However, the CFAs in the second sample did not provide clear support to any solution. Conclusions: The FFMQ showed unclear evidence on its latent structure. We propose researchers and users of the FFMQ to use the most fitting solution between the 5 and 6-facet solutions in their data, since the 4-facet solution is difficult to interpret. We also propose cautionary notes and guidelines for researchers and applied users of the FFMQ and regarding this instrument. We conclude that more research is needed in mindfulness assessment to provide robust measurement

    Demographic history and population structure of Anopheles pseudopunctipennis in Argentina based on the mitochondrial COI gene

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    Background: Anopheles pseudopunctipennis is an important malaria vector in the Neotropical region and the only species involved in Plasmodium transmission in the Andean foothills. Its wide geographical distribution in America, high preference for biting humans and capacity to rest inside dwellings after feeding, are attributes contributing to its vector status. Previous reports have tried to elucidate its taxonomic status, distinguishing populations from North, Central and South America. In the present study we used a mitochondrial marker to examine the demographic history of An. pseudopunctipennis in northwestern Argentina. Methods: Twelve localities were selected across 550 km of the distribution of this species in Argentina, including two near the Bolivian border and several in South Tucumán, for sampling. A fragment of the cytochrome oxidase I (COI) gene was sequenced and haplotype relationships were analyzed by a statistical parsimony network and a Neighbor-Joining (NJ) tree. Genetic differentiation was estimated with FS T. Historical demographic processes were evaluated using diversity measures, neutrality tests and mismatch distribution. Results: Forty-one haplotypes were identified, of which haplotype A was the most common and widely distributed. Neither the network nor the NJ tree showed any geographic differentiation between northern and southern populations. Haplotype diversities, Tajima’s D T and Fu & Li’s F and D neutrality tests and mismatch distribution supported a scenario of Holocene demographic expansion. Conclusion: The demographic pattern suggests that An. pseudopunctipennis has undergone a single colonization process, and the ancestral haplotype is shared by specimens from all localities, indicating mitochondrial gene flow. Genetic differentiation was minimal, observed only between one northern and one southern locality. The estimated time of the population expansion of this species was during the Holocene. These data suggest that regional vector control measures would be equally effective in both northern and southern localities sampled, but also that insecticide resistant genes may spread rapidly within this region.Fil: Dantur Juri, Maria Julia. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Superior de Entomología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Moreno, Marta. New York State Department of Health; Estados Unidos. State University Of New York; Estados Unidos. University Of California At San Diego; Estados UnidosFil: Prado Izaguirre, Mónica J.. Universidad Central de Venezuela; VenezuelaFil: Navarro, Juan C.. Universidad Central de Venezuela; VenezuelaFil: Zaidenberg, Mario O.. Ministerio de Salud de la Nación. Coordinación Nacional de Control de Vectores; ArgentinaFil: Almiron, Walter Ricardo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Claps, Guillermo Luis. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Superior de Entomología; ArgentinaFil: Conn, Jan E.. New York State Department of Health; Estados Unidos. State University Of New York; Estados Unido

    Imaging in Suspected Renal Colic: Systematic Review of the Literature and Multispecialty Consensus

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    Background Renal colic is common, and CT is frequently utilized when the diagnosis of kidney stones is suspected. CT is accurate but exposes patients to ionizing radiation and has not been shown to alter either interventional approaches or hospital admission rates. This multi-organizational transdisciplinary collaboration sought evidence-based, multispecialty consensus on optimal imaging across different clinical scenarios in patients with suspected renal colic in the acute setting. Methods In conjunction with the American College of Emergency Physicians (ACEP) eQual network, we formed a nine-member panel with three physician representatives each from ACEP, the ACR, and the American Urology Association. A systematic literature review was used as the basis for a three-step modified Delphi process to seek consensus on optimal imaging in 29 specific clinical scenarios. Results From an initial search yielding 6,337 records, there were 232 relevant articles of acceptable evidence quality to guide the literature summary. At the completion of the Delphi process consensus, agreement was rated as perfect in 15 (52%), excellent in 8 (28%), good in 3 (10%), and moderate in 3 (10%) of the 29 scenarios. There were no scenarios where at least moderate consensus was not reached. CT was recommended in 7 scenarios (24%), with ultrasound in 9 (31%) and no further imaging needed in 12 (45%). Summary Evidence and multispecialty consensus support ultrasound or no further imaging in specific clinical scenarios, with reduced-radiation dose CT to be employed when CT is needed in patients with suspected renal colic

    Detección y seguimiento de objetos en vídeos de actividades de vida diaria para rehabilitación de pacientes con daño cerebral adquirido

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    Las técnicas de rehabilitación permiten la recuperación y mejora de las funciones dañadas o deterioradas y ayuda al paciente con DCA a adaptarse a su nueva situación. El avance tecnológico que se ha producido en las últimas décadas, ha impulsado la investigación en el diseño y desarrollo de nuevos modelos de rehabilitación. La tecnología de vídeo interactivo se convierte en un elemento de apoyo en estos nuevos modelos rehabilitadores. Se hace necesario desarrollar nuevos algoritmos de segmentación y seguimiento que permitan dotar de información adicional a los vídeos. En este trabajo se han implementado y evaluado dos métodos que permiten realizar la detección y el seguimiento de objetos de interés

    Library of Seleno-Compounds as Novel Agents against Leishmania Species

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    The in vitro leishmanicidal activities of a series of 48 recently synthesized selenium derivatives against Leishmania infantum and Leishmania braziliensis parasites were tested using promastigotes and intracellular amastigote forms. The cytotoxicity of the tested compounds for J774.2 macrophage cells was also measured in order to establish their selectivity. Six of the tested compounds (compounds 8, 10, 11, 15, 45, and 48) showed selectivity indexes higher than those of the reference drug, meglumine antimonate (Glucantime), for both Leishmania species; in the case of L. braziliensis, compound 20 was also remarkably selective. Moreover, data on infection rates and amastigote numbers per macrophage showed that compounds 8, 10, 11, 15, 45, and 48 were the most active against both Leishmania species studied. The observed changes in the excretion product profile of parasites treated with these six compounds were also consistent with substantial cytoplasmic alterations. On the other hand, the most active compounds were potent inhibitors of Fe superoxide dismutase (Fe-SOD) in the two parasite species considered, whereas their impact on human CuZn-SOD was low. The high activity, low toxicity, stability, low cost of the starting materials, and straightforward synthesis make these compounds appropriate molecules for the development of affordable antileishmanicidal agents

    Changes in brown adipose tissue lipid mediator signatures with aging, obesity, and DHA supplementation in female mice

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    Brown adipose tissue (BAT) dysfunction in aging and obesity has been related to chronic unresolved inflammation, which could be mediated by an impaired production of specialized proresolving lipid mediators (SPMs), such as Lipoxins-LXs, Resolvins-Rvs, Protectins-PDs, and Maresins-MaRs. Our aim was to characterize the changes in BAT SPMs signatures and their association with BAT dysfunction during aging, especially under obesogenic conditions, and their modulation by a docosahexaenoic acid (DHA)-rich diet. Lipidomic, functional, and molecular studies were performed in BAT of 2-and 18-month- old lean (CT) female mice and in 18-month- old diet-induced obese (DIO) mice fed with a high-fat diet (HFD), or a DHA-enriched HFD. Aging downregulated Prdm16 and UCP1 levels, especially in DIO mice, while DHA partially restored them. Arachidonic acid (AA)-derived LXs and DHA-derived MaRs and PDs were the most abundant SPMs in BAT of young CT mice.Interestingly, the sum of LXs and of PDs were significantly lower in aged DIO mice compared to young CT mice. Some of the SPMs most significantly reduced in obese-aged mice included LXB4, MaR2, 4S,14S-diHDHA, 10S,17S-diHDHA (a.k.a. PDX), and RvD6. In contrast, DHA increased DHA-derived SPMs, without modifying LXs. However, MicroPET studies showed that DHA was not able to counteract the impaired cold exposure response in BAT of obese-aged mice. Our data suggest that a defective SPMs production could underlie the decrease of BAT activity observed in obese-aged mice, and highlight the relevance to further characterize the physiological role and therapeutic potential of specific SPMs on BAT development and function

    EXPLORING THE IMPACT OF APOE POLYMORPHISM ON THE MOLECULAR, MORPHOLOGICAL AND FUNCTIONAL PROFILE OF iPSC-DERIVED ASTROCYTES FROM ALZHEIMER'S PATIENTS

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    Comunicación presentada a FENS Forum 2022Alzheimer¿s disease (AD) is pathologically characterised by the presence of amyloid-beta plaques, neurofibrillary tangles containing hyperphosphorylated Tau protein, neuroinflammation and neuronal death leading to progressive cognitive impairment. The ¿4 allele of the gene encoding apolipoprotein E (APOE), which is mainly expressed in glial cells, is the strongest genetic risk factor for sporadic AD. Increasing evidence has shown that APOE4 may disrupt normal astrocyte activity, potentially contributing to AD pathology, but the impact of different APOE alleles on astrocyte differentiation, maturation and function is not yet fully understood. To go in depth on these questions, we obtained induced pluripotent stem cells (iPSCs) from fibroblasts of AD patients carrying ¿3 and ¿4 alleles (in homozygosis) and from healthy patients. We also used gene-edited iPSC lines homozygous for the main APOE variants and an APOE knock-out line. iPSC-derived human astrocytes were generated by establishing a differentiation protocol through the consecutive addition of small molecules and growth factors, and the expression of typical markers (GFAP, GLT1, AQP4 and S100beta) and APOE was analysed. In addition, astrocytes exhibited functional features like glutamate uptake capacity and calcium waves production. They also responded to an inflammatory stimulus (IL-1beta and TNF-alpha) or to the presence of amyloid-beta 1-42 peptide by changing their morphology and increasing the expression levels of pro-inflammatory factors and cytokines. Our results shed light on the potential dual role of APOE polymorphism and the individual¿s genetic background in favouring or perhaps preventing AD pathology
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