Numerical analysis of gas-solidsflow hydrodynamics and heat transfer in two outlet configurationindustrial riser using mesoscale theory to predict the interfacialdrag

Se analizan numéricamente dos configuraciones de un riser del proceso FCC variando la disposición de la salida superior, usando un modelo CFD en 2 D que incluye el Modelo de los Dos Fluidos (TMF), la Teoría Cinética del Flujo Granular (KTGF) y como modelo de arrastre el modelo de la Minimización de la Energía Multi-Escala (EMMS). El modelo se resuelve a través del programa ANSYS Fluent® 14.5 solucionando las ecuaciones de balance de masa, momentum y energía; y ecuaciones constitutivas para calcular la interacción entre las fases, la fase sólida con las paredes, y las propiedades de la fase granular. El modelo propuesto en este trabajo predice adecuadamente el comportamiento del flujo gas-sólido, prediciendo diferentes patrones de flujo en las coordenadas axial y radial del riser; así como zonas concentradas y diluidas de sólidos en la parte baja y alta del riser, respectivamente. Las fluctuaciones en la concentración y las velocidades de los sólidos tanto radial como axialmente que se observan son producto del alto grado de mezclado radial que se acentúa cerca de las paredes del riser debido al arrastre considerado por el modelo utilizado. Por otro lado se observa una rápida estabilización térmica radial y axial alcanzando en poco tiempo el estado estacionario. Los perfiles obtenidos en las dos configuraciones analizadas son muy similares, lo que motiva a que en trabajos futuros se analicen otras configuraciones de salida del riser que permitan mejorar los patrones de concentración y velocidades de los sólidos.In the FCC process two configurations riser are numerically analyzed varying the upper outlet orientation using a 2 D CFD model which includes the Two Fluid Model (TFM), Kinetic Theory of Granular Flow (KTGF), and Energy Minimization Multi-Scale (EMMS) theory as drag model. This model is solved using the ANSYS Fluent® 14.5 software, solving the governing equations of mass, momentum, and energy balance; and the constitutive equations to calculate interfacial interaction, wall-solid phase interaction, and granular phase properties. The model proposed in this work properly predicts the gas-solid flow behavior, predicting different solid flow patterns in radial and axial riser directions, as well as concentrated and diluted zones at riser's top and bottom respectively. The radial and axial solids concentration and velocities profiles fluctuations observed are produced by the high radial solid mix which is higher near the riser walls due to drag force considered by the model used. On the other hand, a rapid radial and axial thermal stabilization is observed reaching the steady state rapidly. The profiles obtained from riser configurations analyzed are very similar, so in future works other riser outlets configurations will be analyzed to try to improve the solid concentration and velocity profiles.Peer Reviewe

Immunity and vaccine development efforts against Trypanosoma cruzi

Artículo de revisión especializadoTrypanosoma cruzi (T. cruzi) is the causative agent for Chagas disease (CD). There is a critical lack of methods for prevention of infection or treatment of acute infection and chronic disease. Studies in experimental models have suggested that the protective immunity against T. cruzi infection requires the elicitation of Th1 cytokines, lytic antibodies and the concerted activities of macrophages, T helper cells, and cytotoxic T lymphocytes (CTLs). In this review, we summarize the research efforts in vaccine development to date and the challenges faced in achieving an efficient prophylactic or therapeutic vaccine against human CD.UTM

Fatty Acid Composition of Developing Sea Buckthorn (Hippophae rhamnoides L.) Berry and the Transcriptome of the Mature Seed

Background: Sea buckthorn (Hippophae rhamnoides L.) is a hardy, fruit-producing plant known historically for its medicinal and nutraceutical properties. The most recognized product of sea buckthorn is its fruit oil, composed of seed oil that is rich in essential fatty acids, linoleic (18:2\u3c9-6) and \u3b1-linolenic (18:3\u3c9-3) acids, and pulp oil that contains high levels of monounsaturated palmitoleic acid (16:1\u3c9-7). Sea buckthorn is fast gaining popularity as a source of functional food and nutraceuticals, but currently has few genomic resources; therefore, we explored the fatty acid composition of Canadian-grown cultivars (ssp. mongolica) and the sea buckthorn seed transcriptome using the 454 GS FLX sequencing technology. Results: GC-MS profiling of fatty acids in seeds and pulp of berries indicated that the seed oil contained linoleic and \u3b1-linolenic acids at 33-36% and 30-36%, respectively, while the pulp oil contained palmitoleic acid at 32-42%. 454 sequencing of sea buckthorn cDNA collections from mature seeds yielded 500,392 sequence reads, which identified 89,141 putative unigenes represented by 37,482 contigs and 51,659 singletons. Functional annotation by Gene Ontology and computational prediction of metabolic pathways indicated that primary metabolism (protein>nucleic acid>carbohydrate>lipid) and fatty acid and lipid biosynthesis pathways were highly represented categories. Sea buckthorn sequences related to fatty acid biosynthesis genes in Arabidopsis were identified, and a subset of these was examined for transcript expression at four developing stages of the berry. Conclusion: This study provides the first comprehensive genomic resources represented by expressed sequences for sea buckthorn, and demonstrates that the seed oil of Canadian-grown sea buckthorn cultivars contains high levels of linoleic acid and \u3b1-linolenic acid in a close to 1:1 ratio, which is beneficial for human health. These data provide the foundation for further studies on sea buckthorn oil, the enzymes involved in its biosynthesis, and the genes involved in the general hardiness of sea buckthorn against environmental conditions.Peer reviewed: YesNRC publication: Ye

Simulating rewetting events in intermittent rivers and ephemeral streams: A global analysis of leached nutrients and organic matter

Climate change and human pressures are changing the global distribution and the ex‐ tent of intermittent rivers and ephemeral streams (IRES), which comprise half of the global river network area. IRES are characterized by periods of flow cessation, during which channel substrates accumulate and undergo physico‐chemical changes (precon‐ ditioning), and periods of flow resumption, when these substrates are rewetted and release pulses of dissolved nutrients and organic matter (OM). However, there are no estimates of the amounts and quality of leached substances, nor is there information on the underlying environmental constraints operating at the global scale. We experi‐ mentally simulated, under standard laboratory conditions, rewetting of leaves, river‐ bed sediments, and epilithic biofilms collected during the dry phase across 205 IRES from five major climate zones. We determined the amounts and qualitative character‐ istics of the leached nutrients and OM, and estimated their areal fluxes from riverbeds. In addition, we evaluated the variance in leachate characteristics in relation to selected environmental variables and substrate characteristics. We found that sediments, due to their large quantities within riverbeds, contribute most to the overall flux of dis‐ solved substances during rewetting events (56%–98%), and that flux rates distinctly differ among climate zones. Dissolved organic carbon, phenolics, and nitrate contrib‐ uted most to the areal fluxes. The largest amounts of leached substances were found in the continental climate zone, coinciding with the lowest potential bioavailability of the leached OM. The opposite pattern was found in the arid zone. Environmental vari‐ ables expected to be modified under climate change (i.e. potential evapotranspiration, aridity, dry period duration, land use) were correlated with the amount of leached sub‐ stances, with the strongest relationship found for sediments. These results show that the role of IRES should be accounted for in global biogeochemical cycles, especially because prevalence of IRES will increase due to increasing severity of drying event

Volviéndonos mejores: necesidad de acción inmediata ante el reto de la obesidad. Una postura de profesionales de la salud.

La creciente epidemia de obesidad ha sido uno de los retos más importantes de salud pública en México durante los últimos años. Con apoyo de la Federación Mundial de Obesidad, en 2021 formamos un grupo de profesionales para identificar y resumir las acciones prioritarias en las que puede enfocarse nuestro país para hacer frente a esta epidemia. Al proceso de desarrollo y discusión de este grupo se sumaron más de 1 000 profesionales de la salud para retomar recomendaciones de documentos y guías de alto nivel previamente publicados. En conmemoración del Día Mundial de la Obesidad, en este 2022 se presenta esta postura como insumo para el desarrollo de acciones en el ámbito profesional y de los diferentes sectores, en la que se incluyen 10 recomendaciones de acción, desde la perspectiva poblacional hasta la atención individualizada, y se enfatiza en la importancia de la participación social, de las intervenciones integrales con visión centrada en la persona y de la sostenibilidad planetaria, además de mejorar la educación y las campañas de difusión, propiciar un ambiente promotor de entornos activos y blindar de conflictos de interés los esfuerzos de prevención y control. La postura hace un llamado para abordar la obesidad de manera seria, con base en la evidencia científica, oportuna e integral, con enfoque de curso de vida, de forma ética y sensible, y sin perpetuar las barreras del estigma de peso en la sociedad

Las redes como dispositivos para la gestión educativa en Iberoamérica

La presente aportación se focaliza en cómo el trabajo en red puede ayudar a mejorar la organización y gestión de los centros educativos. Presenta referentes normativos pero también identifica redes centradas en la gestión y pone ejemplos de alguna de ellas. Recoge las aportaciones de 36 especialistas, que han elaborado los informes de 11 países iberoamericanos