2,650 research outputs found

    Microarchitectural changes during development of the cerebellar cortex

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    The cerebellum is a highly conserved structure in the Central Nervous System (CNS) of vertebrates, and is involved in the coordination of voluntary motor behaviour. Supporting this function, the cerebellar cortex presents a layered structure which requires a precise spatial and temporal coordination of proliferation, migration and differentiation events. One of the characteristics of the developing cortex is the formation of the external granule cell layer (EGL) in the outermost part. The EGL is a highly proliferative transient layer which disappears when cells migrate inwards to form the inner granule cell layer. The balance between proliferation and migration leads to changes in EGL thickness, and might be related to >indentations> observed in the surface of the developing chick cerebellum. We have extended the observation of this feature to quail and mouse, supporting the idea that this phenomenon forms part of the mechanisms of cerebellar morphogenesis. Different factors involved in both mitotic activity and migration were analyzed in this study. Our results indicate that proliferation, more than formation of raphes for cell migration, is involved in the formation of indentations in the EGL. In addition, we show that vessels penetrating from the pial surface divide the EGL into regular regions at the time of the appearance of bulges and furrows. We conclude that indentations are the result of a coincidence in time of both the increase in thickness of the EGL and the establishment of the embryonic vascular pattern, which confers a characteristic transitory morphology to the surface of folia. © 2009.Peer Reviewe

    Photosynthetic biogas upgrading to bio-methane: Boosting nutrient recovery via biomass productivity control

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    Producción CientíficaA pilot high rate algal pond (HRAP) interconnected to an external CO2–H2S absorption column via settled broth recirculation was used to simultaneously treat a synthetic digestate and to upgrade biogas to a bio-methane with sufficient quality to be injected into natural gas grids. An innovative HRAP operational strategy with biomass recirculation based on the control of algal-bacterial biomass productivity (2.2, 4.4 and 7.5 g m− 2 d− 1) via settled biomass wastage was evaluated in order to enhance nutrient recovery from digestate at a constant hydraulic retention time. The influence of the recycling liquid to biogas (L/G) ratio on the quality of the upgraded biogas was assessed. The bio-methane composition under a L/G ratio of 1 (0.4 ± 0.1% CO2, 0.03 ± 0.04% O2, 2.4 ± 0.2% N2 and 97.2 ± 0.2% CH4) complied with the technical specifications of most European bio-methane legislations regardless of the biomass productivity established. The HRAP operational strategy applied allowed increasing the N and P recovery from 19 and 22% to 83 and 100%, respectively, when the biomass productivity was increased from 2.2 to 7.5 g m− 2 d− 1. Finally, the dynamics of microalgae and bacteria population structure were characterized by morphological identification and Denaturing Gradient Gel Electrophoresis analysis.Ministerio de Economía, Industria y Competitividad (Proyect CTM2015-70442-R

    Effects of an integrated harvest system on the quality of olive fruit for small producers

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    Small producers confront specific challenges when they opt to produce high-quality olive fruit. Limited resources for investing in harvest machinery and manpower are the main reasons for continuing a traditional harvest method that puts the final product and its economic value at risk. This paper discusses the efficiency of an integrated harvest system as a possible solution to these specific challenges. The system is formed by a newly designed manual harvesting device and the use of a cooling room near the olive grove. Both systems were evaluated to assess their feasibility for optimum conditions before processing. The combined effect of the harvesting method and cold storage on the fruit characteristics (incidence of decay, skin color, weight loss, firmness, respiration, and ethylene production) was evaluated on three different varieties (‘Arbequina’, ‘Picual’ and ‘Verdial’) and four different storage times (0, 4, 8, and 14 days). The results indicate that the proposed harvesting method in combination with an appropriate cooling system offers an affordable alternative for obtaining fruit with the best physiological characteristics.Efectos de un sistema integrado de recolección para pequeños productores en la calidad de la aceituna recogida. Los pequeños productores se enfrentan a retos específicos, cuando optan por producir aceitunas de alta calidad. La imposibilidad económica de invertir, tanto en maquinaria de cosecha, como en mano de obra es la razón principal que obliga a continuar una recolección tradicio-nal que pone en riesgo el producto final y su valor económico. Este estudio analiza la eficiencia de un sistema de recolección integrado como una posible solución a estos desafíos específicos. El sistema está formado por un dispositivo de recogida manual de nuevo diseño y el uso de una cámara de frío en la finca. El efecto combinado del método de recolección presentado y el almacenamiento en frío sobre las características de la fruta (incidencia de podredumbre, color de piel, pérdida de peso, firmeza, respiración y producción de etileno) se evaluó en tres variedades diferentes (‘Arbequina’, ‘Picual’ y ‘ Verdial’) y diferentes tiempos de almacenamiento (0, 4, 8, 14 días). Los re-sultados indican que la combinación de un método de recolección mecánica y un sistema de enfriamiento adecuado ofrece una alternativa económicamente asequible para obtener frutos con las mejores características fisiológicas.Spanish Ministry of Science and Innovation AGL2015-71585-

    Size-induced superantiferromagnetism with reentrant spin-glass behavior in metallic nanoparticles of TbCu2

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    An unusual 4f -superantiferromagnetic state characterized by simultaneous antiferromagnetic and spin-glass behaviors induced by particle-size reduction is revealed in metallic nanoparticles (≈ 9 nm) of TbCu 2 . The Néel temperature is 46 K and the glassy freezing is below ≈ 9 K and governed by a critical slowing down process. Neutron diffraction at 1.8 K establishes the superantiferromagnetism. The latter is settled by the nanoparticle moments and the freezing mechanism is provided by the surface spins

    Reaction pathways and textural aspects of the replacement of anhydrite by calcite at 25 °C

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    The replacement of sulfate minerals by calcium carbonate polymorphs (carbonation) has important implications in various geological processes occurring in Earth surface environments. In this paper we report the results of an experimental study of the interaction between anhydrite (100), (010), and (001) surfaces and Na₂CO₃ aqueous solutions under ambient conditions. Carbonation progress was monitored by glancing incidence X-ray diffraction (GIXRD) and scanning electron microscopy (SEM). We show that the reaction progresses through the dissolution of anhydrite and the simultaneous growth of calcite. The growth of calcite occurs oriented on the three anhydrite cleavage surfaces and its formation is accompanied by minor vaterite. The progress of the carbonation always occurs from the outer-ward to the inner-ward surfaces and its rate depends on the anhydrite surface considered, with the (001) surface being much more reactive than the (010) and (100) surfaces. The thickness of the formed carbonate layer grows linearly with time. The original external shape of the anhydrite crystals and their surface details (e.g., cleavage steps) are preserved during the carbonation reaction. Textural characteristics of the transformed regions, such as the gradation in the size of calcite crystals, from ~2 μm in the outer region to ~17 μm at the calcite-anhydrite interface, the local preservation of calcite crystalographic orientation with respect to anhydrite and the distribution of the microporosity mainly within the carbonate layer without development of any significant gap at the calcite-anhydrite interface. Finally, we compare these results on anhydrite carbonation with those on gypsum carbonation and can explain the differences on the basis of four parameters: (1) the molar volume change involved in the replacement process in each case, (2) the lack/existence of epitactic growth between parent and product phases, (3) the kinetics of dissolution of the different surfaces, and (4) the chemical composition (amount of structural water) of the parent phases

    Prediction of adverse neonatal outcome at admission for early-onset preeclampsia with severe features

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    Preeclampsia remains the leading cause of maternal morbidity and mortality. Consequently, research has focused on validating tools to predict maternal outcomes regarding clinical and biochemical features from the maternal compartment. However, preeclampsia also leads to neonatal complications due to placental insufficiency and prematurity, being the early-onset type associated with the poorest outcome. Hence, it is imperative to study whether these existing tools can predict adverse neonatal outcome.To assess the predictive value for adverse neonatal outcome of Doppler ultrasound, angiogenic factors and multi-parametric risk-score models in women with early-onset severe preeclampsia.This is a prospective cohort study of consecutive singleton pregnancies complicated by early-onset (developed before 34 week's gestation) severe preeclampsia.63 women with early-onset severe preeclampsia, 18 (28.6%) presented an adverse neonatal outcome. Placental growth factor (PlGF) showed the best discrimination between neonatal outcomes among angiogenic factors. PREP-L score is a multi-parametric risk-score for the prediction of complications in early-onset preeclampsia which includes maternal characteristics and clinical and analytical data obtained at admission. Good predictive values for the prediction of neonatal complications were found with the combination of PREP-L score with advanced Doppler (AUC ROC 0.9 95% CI 0.82-0.98]) and with PlGF levels (AUC ROC 0.91 [95% CI 0.84-0.98]).The combination of maternal risk scoring (PREP-L score) with angiogenic factors or fetal Doppler ultrasound at the time of diagnosis of early-onset preeclampsia with severe features performs well in predicting adverse neonatal outcome.Copyright © 2023 International Society for the Study of Hypertension in Pregnancy. Published by Elsevier B.V. All rights reserved

    Proteomic profiling reveals mitochondrial dysfunction in the cerebellum of transgenic mice overexpressing DYRK1A, a Down syndrome candidate gene

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    DYRK1A is a dual-specificity kinase that is overexpressed in Down syndrome (DS) and plays a key role in neurogenesis, neuronal differentiation and function, cognitive phenotypes, and aging. Dyrk1A has also been implicated in cerebellar abnormalities observed in association with DS, and normalization of Dyrk1A dosage rescues granular and Purkinje cell densities in a trisomic DS mouse model. However, the underlying molecular mechanisms governing these processes are unknown.To shed light on the effects of Dyrk1A overexpression in the cerebellum, here we investigated the cerebellar proteome in transgenic Dyrk1A overexpressing mice in basal conditions and after treatment with green tea extract containing epigallocatechin-3-gallate (EGCG), a DYRK1A inhibitor.Our results showed that Dyrk1A overexpression alters oxidative phosphorylation and mitochondrial function in the cerebellum of transgenic mice. These alterations are significantly rescued upon EGCG-containing green tea extract treatment, suggesting that its effects in DS could depend in part on targeting mitochondria, as shown by the partially restoration by the treatment of the increased mtDNA copy number in TG non-treated mice.Copyright © 2022 De Toma, Ortega, Fernández-Blanco, Calderón, Barahona, Trullàs, Sabidó and Dierssen
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