Browsing by Author "Amorim, Ana"
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- Analysis of integrated calcium looping alternatives in a cement plantPublication . Amorim, Ana; Filipe, Rui; Matos, Henrique A.Calcium looping is a promising post-combustion CO2 capturing technology, highly compatible with the cement industry, one of the major industrial sources of CO2 emissions. Limestone, a raw material for clinker, forms lime, a calcium looping adsorbent. Thus, it is possible to maximize the synergies between a cement plant and a calcium looping unit by establishing an integrated configuration. Nevertheless, the integration of calcium looping in cement plants has not yet been thoroughly studied. This study examines different integration alternatives, developing models for the preheater and calciner using Aspen Plus, validated with operational data, alongside an entrained-flow carbonator model considering adsorbent deactivation. By combining these models, six integrated configurations are proposed and compared with the tail-end calcium looping configuration. The integrated configurations show a reduction in fuel consumption and net energy consumption for the same CO2 avoided emissions. The most promising configuration was identified and a comparative techno-economic analysis was conducted.
- Determination of cell abundances and paralytic shellfish toxins in cultures of the dinoflagellate gymnodinium catenatum by fourier transform near infrared spectroscopyPublication . B. Lopes, Marta; Amorim, Ana; Calado, Cecília; Reis Costa, PedroHarmful algal blooms are responsible worldwide for the contamination of fishery resources, with potential impacts on seafood safety and public health. Most coastal countries rely on an intense monitoring program for the surveillance of toxic algae occurrence and shellfish contamination. The present study investigates the use of near infrared (NIR) spectroscopy for the rapid in situ determination of cell concentrations of toxic algae in seawater. The paralytic shellfish poisoning (PSP) toxin-producing dinoflagellate Gymnodinium catenatum was selected for this study. The spectral modeling by partial least squares (PLS) regression based on the recorded NIR spectra enabled the building of highly accurate (R2 = 0.92) models for cell abundance. The models also provided a good correlation between toxins measured by the conventional methods (high-performance liquid chromatography with fluorescence detection (HPLC-FLD)) and the levels predicted by the PLS/NIR models. This study represents the first necessary step in investigating the potential of application of NIR spectroscopy for algae bloom detection and alerting.
- microRNA 181a regulates IFN-γ expression in effector CD8+T cell differentiationPublication . Amado, Tiago; Amorim, Ana; Enguita, Francisco J.; Romero, Paula V.; Inácio, Daniel; Miranda, Marta P.; Winter, Samntha J.; Simas, Pedro J.; Krueger, Andreas; Schmolka, Nina; Silva-Santos, Bruno; Gomes, Anita Q.In the past years, the importance of microRNAs in the development and maintenance of cell identity and on the regulation of cytokine expression within cells of the immune system has gained increasing strength. CD8+ T cells are key players in immunity against intracellular infections, namely viral infections, and tumors. The main cytokine associated with these protective responses is interferon-IFN-γ, whose production is known to be regulated at the transcriptional level during CD8+ T cell differentiation. In this study, we show that microRNAs constitute a post-transcriptional brake to IFN-γ expression by CD8+ T cells as the genetic interference with the Dicer processing machinery resulted in the increased production of IFNγ by both thymic and peripheral CD8+ T cells. Using a YFP reporter mouse for IFN-γ locus activity we compared the microRNA repertoires associated with the presence or absence of IFN-γ expression. This allowed us to identify a set of candidates, including miR-181a and miR-451, which were functionally tested in overexpression experiments using synthetic mimics in peripheral CD8+ T cell cultures. We found that miR-181a limits IFN-γ production by suppressing the expression of the transcription factor Id2, which in turn promotes the Ifng expression program. Importantly, upon MuHV-4 challenge, miR-181a-deficient mice showed a more vigorous IFNγ+ CD8+ T cell response, and were able to control murid gammaherpesvirus-4 virus infection significantly more efficiently than control mice. Collectively, these data establish a novel role for miR-181a in regulating IFN-γ–mediated effector CD8+ T cell responses in vitro and in vivo.
- MicroRNA-146a controls functional plasticity in γδ T cells by targeting NOD1Publication . Schmolka, Nina; Papotto, Pedro H.; Romero, Paula Vargas; Amado, Tiago; Enguita, Francisco J.; Amorim, Ana; Rodrigues, Ana F.; Gordon, Katrina E.; Coroadinha, Ana S.; Boldin, Mark; Serre, Karine; Buck, Amy H.; Gomes, Anita Quintal; Silva-Santos, Brunoγδ T cells are major providers of proinflammatory cytokines. They are preprogrammed in the mouse thymus into distinct subsets producing either interleukin-17 (IL-17) or interferon-γ (IFN-γ), which segregate with CD27 expression. In the periphery, CD27- γδ (γδ27-) T cells can be induced under inflammatory conditions to coexpress IL-17 and IFN-γ; the molecular basis of this functional plasticity remains to be determined. On the basis of differential microRNA (miRNA) expression analysis and modulation in γδ T cell subsets, we identified miR-146a as a thymically imprinted post-transcriptional brake to limit IFN-γ expression in γδ27- T cells in vitro and in vivo. On the basis of biochemical purification of Argonaute 2-bound miR-146a targets, we identified Nod1 to be a relevant mRNA target that regulates γδ T cell plasticity. In line with this, Nod1-deficient mice lacked multifunctional IL-17+ IFN-γ+ γδ27- cells and were more susceptible to Listeria monocytogenes infection. Our studies establish the miR-146a/NOD1 axis as a key determinant of γδ T cell effector functions and plasticity.
- MicroRNA-146a controls IFN-g production and functional plasticity of murine gd T cells by targeting Nod1Publication . Schmolka, Nina; Papotto, Pedro H.; Romero, Paula Vargas; Amado, Tiago; Enguita, Francisco J.; Amorim, Ana; Gordon, Katrina E.; Boldin, Mark; Serre, Karine; Buck, Amy H.; Gomes, Anita Quintal; Silva-Santos, Brunoγδ T cells have emerged as key providers of the proinflammatory cytokines interleukin 17 (IL-17) and interferon-γ (IFN-γ) in various models of infection, inflammation, and autoimmunity. Our previous epigenetic and transcriptional analyses have shown that whereas CD27+ γδ T cells are committed to IFN-γ expression, the IL-17 producing CD27- subset has limited plasticity to co-express both cytokines under inflammatory conditions (Schmolka et al. Nat Immunol 2013). To further understand the molecular control of this plasticity we now investigated the potential role of microRNA (miRNA)-mediated post-transcriptional regulation.
- MicroRNA-181a regulates IFN-γ expression in effector CD8+ T cell differentiationPublication . Amado, Tiago; Amorim, Ana; Enguita, Francisco J.; Romero, Paula V.; Inácio, Daniel; Miranda, Marta Pires; Winter, Samantha J.; Simas, J. Pedro; Krueger, Andreas; Schmolka, Nina; Silva-Santos, Bruno; Gomes, Anita Q.CD8+ T cells are key players in immunity against intracellular infections and tumors. The main cytokine associated with these protective responses is interferon-γ (IFN-γ), whose production is known to be regulated at the transcriptional level during CD8+ T cell differentiation. Here we found that microRNAs constitute a posttranscriptional brake to IFN-γ expression by CD8+ T cells since the genetic interference with the Dicer processing machinery resulted in the overproduction of IFN-γ by both thymic and peripheral CD8+ T cells. Using a gene reporter mouse for IFN-γ locus activity, we compared the microRNA repertoires associated with the presence or absence of IFN-γ expression. This allowed us to identify a set of candidates, including miR-181a and miR-451, which were functionally tested in overexpression experiments using synthetic mimics in peripheral CD8+ T cell cultures. We found that miR-181a limits IFN-γ production by suppressing the expression of the transcription factor Id2, which in turn promotes the Ifng expression program. Importantly, upon the MuHV-4 challenge, miR-181a-deficient mice showed a more vigorous IFN-γ+ CD8+ T cell response and were able to control viral infection significantly more efficiently than control mice. These data collectively establish a novel role for miR-181a in regulating IFN-γ-mediated effector CD8+ T cell responses in vitro and in vivo.