2,640 research outputs found

    Foxj1a is expressed in ependymal precursors, controls central canal position and is activated in new ependymal cells during regeneration in zebrafish

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    © 2017 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are creditedZebrafish are able to regenerate the spinal cord and recover motor and sensory functions upon severe injury, through the activation of cells located at the ependymal canal. Here, we show that cells surrounding the ependymal canal in the adult zebrafish spinal cord express Foxj1a. We demonstrate that ependymal cells express Foxj1a from their birth in the embryonic neural tube and that Foxj1a activity is required for the final positioning of the ependymal canal. We also show that in response to spinal cord injury, Foxj1a ependymal cells actively proliferate and contribute to the restoration of the spinal cord structure. Finally, this study reveals that Foxj1a expression in the injured spinal cord is regulated by regulatory elements activated during regeneration. These data establish Foxj1a as a pan-ependymal marker in development, homeostasis and regeneration and may help identify the signals that enable this progenitor population to replace lost cells after spinal cord injury.This research was supported by FCT (Portugal) grants (PTDC/BIM-MED/1375/2012 and PTDC/BIM-MED/3295/2014) given to L.S. L.S. was supported by an IF contract from FCT (Portugal). A.R. was supported by a postdoctoral fellowship of the FCT (Portugal) (SFRH/BPD/100162/2014) and EMBO (605-2012)info:eu-repo/semantics/publishedVersio

    Co-gasification of glycerol/fat mixtures in a downflow fixed bed reactor: Preliminary results

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    The aim of this work was to assess the technical viability of glycerol/fat co-gasification. The gasification performance was studied in a downflow fixed bed reactor using steam as oxidizing agent. Tests were performed with a mixture of 10% of fat and 52% of water, and the effect of temperature was evaluated in the 800 oC to 950 oC range. Samples of dry gas from the gasifier were collected and analysed by gas chromatography in order to determine the CO, CO2, CH4 and H2 content. The results revealed that the co-gasification of glycerol/fat mixtures seems to be a feasible technical option. Best results of the gasification parameters were obtained at the highest tested temperature, 950 ◦C.This work was supported by Portugal 2020 [POCI-01-0145-FEDER-024067] and Fundação para a Ciência e Tecnologia [SFRH/BD/137913/2018].info:eu-repo/semantics/publishedVersio

    Comparative study about heating systems for pultrusion process

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    Different heating systems have been used in pultrusion, where the most widely used heaters are planar resistances. The primary objective of this study was to develop an improved heating system and compare its performance with that of a system with planar resistances. In this study, thermography was used to better understand the temperature profile along the die. Finite element analysis was performed to determine the amount of energy consumed by the heating systems. Improvements were made to the die to test the new heating system, and it was found that the new system reduced the setup time and energy consumption by approximately 57%

    Ultrasonication of insulin-loaded microgel particles produced by internal gelation: impact on particle's size and insulin bioactivity

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    Alginate-dextran sulfate (ADS) microgel has been used to protect insulin from gastrointestinal attack and as a carrier to promote insulin permeation through intestinal epithelium. The throughput of ADS submicron particles generation by emulsification/internal gelation is limited by its wide size distribution. The aim of this work was to study the recovery protocol influence on ADS particles through the determination of its impact on particles’ size distribution and bioactivity. ADS particles showed a wide and multimodal distribution, characterized by a high aggregation phenomenon. In an attempt to reverse particles’ tendency to aggregate and to homogenize particle size ADS populations were submitted to ultrasonication, while particle size distribution, physical and chemical stability, and the bioactivity of entrapped insulin were investigated. After ultrasonication a narrower particle population shifted to the nanoscale, with higher physical stability and significant insulin bioactivity was obtained. Emulsification internal/gelation followed by ultrasonication constituted a valid strategy to obtain ADS particles at the submicron range, with high stability and without significantly compromising insulin bioactivity, so offering promises, under previously well established conditions, to evaluate impact of ADS particle's size on biopharmaceutical and pharmacokinetics phases

    Optimization process of polyester polymer mortars modified with recycled GFRP waste aggregates – application of factorial experiment design-

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    Glass fibre-reinforced plastics (GFRP), nowadays commonly used in the construction, transportation and automobile sectors, have been considered inherently difficult to recycle due to both: cross-linked nature of thermoset resins, which cannot be remolded, and complex composition of the composite itself, which includes glass fibres, matrix and different types of inorganic fillers. Presently, most of the GFRP waste is landfilled leading to negative environmental impacts and supplementary added costs. With an increasing awareness of environmental matters and the subsequent desire to save resources, recycling would convert an expensive waste disposal into a profitable reusable material. There are several methods to recycle GFR thermostable materials: (a) incineration, with partial energy recovery due to the heat generated during organic part combustion; (b) thermal and/or chemical recycling, such as solvolysis, pyrolisis and similar thermal decomposition processes, with glass fibre recovering; and (c) mechanical recycling or size reduction, in which the material is subjected to a milling process in order to obtain a specific grain size that makes the material suitable as reinforcement in new formulations. This last method has important advantages over the previous ones: there is no atmospheric pollution by gas emission, a much simpler equipment is required as compared with ovens necessary for thermal recycling processes, and does not require the use of chemical solvents with subsequent environmental impacts. In this study the effect of incorporation of recycled GFRP waste materials, obtained by means of milling processes, on mechanical behavior of polyester polymer mortars was assessed. For this purpose, different contents of recycled GFRP waste materials, with distinct size gradings, were incorporated into polyester polymer mortars as sand aggregates and filler replacements. The effect of GFRP waste treatment with silane coupling agent was also assessed. Design of experiments and data treatment were accomplish by means of factorial design and analysis of variance ANOVA. The use of factorial experiment design, instead of the one factor at-a-time method is efficient at allowing the evaluation of the effects and possible interactions of the different material factors involved. Experimental results were promising toward the recyclability of GFRP waste materials as polymer mortar aggregates, without significant loss of mechanical properties with regard to non-modified polymer mortars

    Carbon nanotubes based multi-directional strain sensor

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    In this work a new carbon nanotubes (CNT) based multi-directional strain sensor capable of quantifying and indicate strain direction is foreseen. This work investigates the electromechanical behavior of an aligned CNT sensing patch strained at 45◦ in order to validate its multi-directional sensing capability. Vertically aligned CNT forests are produced by chemical vapor deposition (CVD) and then mechanically knocked down onto polyimide (PI) films. Two configurations, diamond (D sample) and square (Sq sample), are considered. The relative electrical resistance (ΔR/R0) and the electrical anisotropy (RB/RA) upon strain increments are analyzed and compared to previous work results (0◦ and 90◦ strain direction). Both 45◦ samples, D and Sq, are sensitive to strain. A correlation between electrical anisotropy behavior and strain direction (0◦, 45◦ and 90◦) is established. The results show that with only an aligned CNT small patch it is possible to quantify and indicate strain in three directions.This work was partially funded under the project “IAMAT – Introduction of advanced materials technologies into new product development for the mobility industries”, with reference MITP-TB/PFM/0005/2013, under the MIT-Portugal program exclusively financed by FCT – Fundação para a Ciência e Tecnologia. This work was also co-financed by national funds through FCT – Fundação para a Ciência e Tecnologia, with the scope of projects with references UIDB/05256/2020 and UIDP/05256/2020”

    Binary Mutual Diffusion Coefficients of Isoniazid Aqueous Solutions at (298.15 and 310.15) K

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    Binary mutual diffusion coefficients measured by the Taylor dispersion method in two different laboratories (University of Naples, Federico II, Italy, and University of Coimbra, Portugal) are reported for aqueous solutions of isoniazid at concentrations from (0.000 to 0.100) mol·dm−3 and at two temperatures (298.15 and 310.15) K. The hydrodynamic radii for the isoniazid in aqueous solution are calculated from the experimental results. In addition, the Hartley equation and the experimental diffusion coefficients are used to estimate activity coefficients for aqueous isoniazid at both temperature

    Interaction between lactose and cadmium chloride in aqueous solutions as seen by diffusion coefficients measurements

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    Diffusion coefficients of an aqueous system containing cadmium chloride 0.100 mol · dm−3 and lactose at different concentrations at 25 °C have been measured, using a conductimetric cell and an automatic apparatus to follow diffusion. The cell relies on an open-ended capillary method and a conductimetric technique is used to follow the diffusion process by measuring the resistance of a solution inside the capillaries, at recorded times. From these results and by ab initio calculations, it was possible to obtain a better understanding of the effect of lactose on transport of cadmium chloride in aqueous solutions

    Transmisión Intergeneracional de Violencia : Una muestra portuguesa de padres e hijos

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    XI Congreso (Inter)Nacional de Psicología Jurídica y Forense, 1-3 Novembro 2018, Granada, EspanhaN/
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