2,030 research outputs found

    Concept mapping as a tool to break disciplinary boundaries: isomerism in biological systems

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    O mapeamento conceitual foi utilizado como uma ferramenta para verificar as mudanças conceituais de estudantes de Ensino Médio após a realização de atividades didáticas desenvolvidas durante as aulas de Química. O objetivo pedagógico a ser atingido foi romper as fronteiras que segregam o conhecimento científico em disciplinas isoladas. Os estudantes foram intencionalmente provocados a relacionar conceitos de Química e de Biologia, a fim de compreender melhor e explicar as conseqüências biológicas da isomeria. Os mapas conceituais elaborados pelos estudantes, antes e após as atividades propostas, evidenciaram o aparecimento de relações entre conceitos químicos e biológicos, que foram avaliadas qualitativamente. Este trabalho mostra que os mapas conceituais podem ser utilizados como ferramentas para auxiliar o professor na realização de práticas didáticas interdisciplinares na escola, bem como para acompanhar o progresso dos estudantes em direção à interdisciplinaridade.Concept mapping was used as a tool for checking the conceptual changes caused by didactic activities implemented during chemistry classes in high school. Its pedagogical aim was to break down the boundaries, which segregate scientific knowledge into isolated disciplines. The students were intentionally provoked to merge concepts from chemistry and biology, in order to better understand and explain the biological consequences of isomerism. The concept maps produced by the students before and after the activities confirmed the appearance of relationships among chemical and biological concepts, which were qualitatively evaluated. This work shows that concept maps can be used to follow the students' progress towards interdisciplinarity, and to help the teacher to devise future classroom activities to reinforce and to expand interdisciplinary relationships.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) - PIBI

    Erratum to "A watershed model of individual differences in fluid intelligence" [Neuropsychologia 91 (2016) 186-198].

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    The publisher regrets that due to an error the full text of Appendix A was missing in the original publication. The missing text is included below. The publisher would like to apologise for any inconvenience caused

    Single-cell multi-omics analysis reveals IFN-driven alterations in T lymphocytes and natural killer cells in systemic lupus erythematosus

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    Background: The characterisation of the peripheral immune system in the autoimmune disease systemic lupus erythematosus (SLE) at the single-cell level has been limited by the reduced sensitivity of current whole-transcriptomic technologies. Here we employ a targeted single-cell multi-omics approach, combining protein and mRNA quantification, to generate a high-resolution map of the T lymphocyte and natural killer (NK) cell populations in blood from SLE patients. Methods: We designed a custom panel to quantify the transcription of 534 genes in parallel with the expression of 51 surface protein targets using the BD Rhapsody AbSeq single-cell system. We applied this technology to profile 20,656 T and NK cells isolated from peripheral blood from an SLE patient with a type I interferon (IFN)-induced gene expression signature (IFNhi), and an age- and sex- matched IFNlow SLE patient and healthy donor. Results: We confirmed the presence of a rare cytotoxic CD4+ T cell (CTL) subset, which was exclusively present in the IFNhi patient. Furthermore, we identified additional alterations consistent with increased immune activation in this patient, most notably a shift towards terminally differentiated CD57+ CD8+ T cell and CD16+ NKdim phenotypes, and the presence of a subset of recently-activated naïve CD4+ T cells. Conclusions: Our results identify IFN-driven changes in the composition and phenotype of T and NK cells that are consistent with a systemic immune activation within the IFNhi patient, and underscore the added resolving power of this multi-omics approach to identify rare immune subsets. Consequently, we were able to find evidence for novel cellular peripheral biomarkers of SLE disease activity, including a subpopulation of CD57+ CD4+ CTLs

    Fisetin derivatives exhibit enhanced anti-inflammatory activity and modulation of endoplasmic reticulum stress

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    Fisetin (FST) is a dietary flavonol that is known to possess multiple relevant bioactivities, raising the question of its potential health benefits and even its use in novel pharmacological approaches. To attain this prospect, some limitations to this molecule, namely its poor bioavailability and solubility, must be addressed. Inflammation and endoplasmic reticulum (ER) stress are often hand in hand in the context of chronic disease. Both are activated upon perceived disturbances in homeostasis but can be deleterious when intensely or chronically activated. We have synthesized a set of FST derivatives trying to improve the biological properties of the parent molecule. These new molecules were tested along with the original compound for their ability to mitigate the activation of these signaling pathways. FST has proven to be effective against the onset of inflammation, reducing NF-κB activation, cytokine release, inflammasome activation and ROS generation, as well as decreasing the activation of the unfolded protein response (UPR). Some of the tested derivatives are also described as new caspase-1 inhibitors, being also capable of reducing pro-inflammatory cytokines and ER stress markers.(undefined

    Short chain U(600) di-urea cross-linked poly(oxyethylene)/siloxane ormolytes doped with lanthanum triflate salt

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    Promising La3+-doped electrolytes based on a hybrid poly(oxyethylene)/siliceous host matrix, U(600), have been produced. The organic and inorganic components of the hybrid structure are covalently bonded through urea linkages. The low molecular weight of the polyether segments of U(600) is thought to be responsible for the total amorphous character and high conductivity at room temperature (1.1×10−4 S cm−1) of these ormolytes.Fundação para a Ciência e a Tecnologia (FCT

    Morphological and conductivity studies of di-ureasil xerogels containing lithium triflate

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    Sol–gel derived poly(oxyethylene)/siloxane hybrids doped with lithium triflate, LiCF3SO3, have been investigated. The host hybrid matrix of these materials, named di-ureasil and represented by U(600), is composed by a siliceous framework to which polyether chains containing 8.5 oxyethylene repeat units are covalently bonded through urea linkages. Xerogel samples U(600)nLiCF3SO3 with n (where n is the molar ratio of oxyethylene moieties per Li+ ion) between ∞ and 0.1 have been examined. X-ray diffraction and differential scanning calorimetry have provided conclusive evidence that the xerogels analyzed are entirely amorphous. The salt-rich material with n=1 exhibits the highest conductivity over the whole range of temperature analyzed (e.g. 4.3×10−6 and 2.0×10−4 Ω−1 cm−1, respectively, at 25 and 94 °C).Fundação para a Ciência e a Tecnologia (FCT

    CD56bright natural killer cells preferentially kill proliferating CD4+ T cells

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    Human CD56br natural killer (NK) cells represent a small subset of CD56+ NK cells in circulation and are largely tissue-resident. The frequency and number of CD56br NK cells in blood has been shown to increase following administration of low-dose IL-2 (LD-IL2), a therapy aimed to specifically expand CD4+ regulatory T cells (Tregs). Given the potential clinical application of LD-IL-2 immunotherapy across several immune diseases, including the autoimmune disease type 1 diabetes, a better understanding of the functional consequences of this expansion is urgently needed. In this study, we developed an in vitro co-culture assay with activated CD4+ T cells to measure NK cell killing efficiency. We show that CD56br and CD56dim NK cells show similar efficiency at killing activated CD4+ conventional T (Tconv) and Treg cell subsets. However, in contrast to CD56dim cells, CD56br NK cells preferentially target highly proliferative cells. We hypothesize that CD56br NK cells have an immunoregulatory role through the elimination of proliferating autoreactive CD4+ Tconv cells that have escaped Treg suppression. These results have implications for the interpretation of current and future trials of LD-IL-2 by providing evidence for a new, possibly beneficial immunomodulatory mechanism of LD-IL-2-expanded CD56br NK cells

    Short-chain di-ureasil ormolytes doped with potassium triflate: Phase diagram and conductivity behavior

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    Di-urea cross-linked poly(oxyethylene)/siloxane hybrids, synthesized by the sol-gel process and containing a wide concentration range of potassium triflate, KCF3SO3, have been analyzed by x-ray diffraction and differential scanning calorimetry. The pseudo-phase diagram proposed has been taken into account in the interpretation of the complex impedance measurements. The xerogels prepared are obtained as transparent, thin monoliths . At room temperature the highest conductivity found was 2 x 10-6Scm-1.Fundação para a Ciência e a Tecnologia (FCT

    Evaluation of a field-deployable Nafion (TM)-based air-drying system for collecting whole air samples and its application to stable isotope measurements of CO2

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    Atmospheric flask samples are either collected at atmospheric pressure by opening a valve of a pre-evacuated flask or pressurized with the help of a pump to a few bar above ambient pressure. Under humid conditions, there is a risk that water vapor in the sample leads to condensation on the walls of the flask, notably at higher than ambient sampling pressures. Liquid water in sample flasks is known to affect the CO2 mixing ratios and also alters the isotopic composition of oxygen (17O and 18O) in CO2 via isotopic equilibration. Hence, for accurate determination of CO2 mole fractions and its stable isotopic composition, it is vital to dry the air samples to a sufficiently low dew point before they are pressurized in flasks to avoid condensation. Moreover, the drying system itself should not influence the mixing ratio and the isotopic composition of CO2 or that of the other constituents under study. For the Airborne Stable Isotopes of Carbon from the Amazon (ASICA) project focusing on accurate measurements of CO2 and its singly substituted stable isotopologues over the Amazon, an air-drying system capable of removing water vapor from air sampled at a dew point lower than -2 °C, flow rates up to 12 L min-1 and without the need for electrical power was needed. Since to date no commercial air-drying device that meets these requirements has been available, we designed and built our own consumable-free, power-free and portable drying system based on multitube Nafion™ gas sample driers (Perma Pure, Lakewood, USA). The required dry purge air is provided by feeding the exhaust flow of the flask sampling system through a dry molecular sieve (type 3A) cartridge. In this study we describe the systematic evaluation of our Nafion™-based air sample dryer with emphasis on its performance concerning the measurements of atmospheric CO2 mole fractions and the three singly substituted isotopologues of CO2 (16O13C16O, 16O12C17O and 16O12C18O), as well as the trace gas species CH4, CO, N2O and SF6. Experimental results simulating extreme tropical conditions (saturated air at 33 °C) indicated that the response of the air dryer is almost instantaneous and that approximately 85 L of air, containing up to 4 % water vapor, can be processed staying below a -2 °C dew point temperature (at 275 kPa). We estimated that at least eight flasks can be sampled (at an overpressure of 275 kPa) with a water vapor content below -2 °C dew point temperature during a typical flight sampling up to 5 km altitude over the Amazon, whereas the remaining samples would stay well below 5 °C dew point temperature (at 275 kPa). The performance of the air dryer on measurements of CO2, CH4, CO, N2O, and SF6 and the CO2 isotopologues 16O13C16O and 16O12C18O was tested in the laboratory simulating real sampling conditions by compressing humidified air from a calibrated cylinder, after being dried by the air dryer, into sample flasks. We found that the mole fraction and the isotopic composition difference between the different test conditions (including the dryer) and the base condition (dry air, without dryer) remained well within or very close to, in the case of N2O, the World Meteorological Organization recommended compatibility goals for independent measurement programs, proving that the test condition induced no significant bias on the sample measurements
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