Publications

Abstract <jats:p>A história da ciência é referida por diversos autores como fundamental para o entendimento da forma como a ciência se desenvolve útil nos processos de aprendizagem e muito relevante para a promoção da humanização da ciência através das biografias. Partindo destas premissas, temas como biografias de cientistas, objectos históricos, espólios de museus, obras e teorias históricas, programas escolares e de divulgação, dialogam, nesta obra, com o ensino formal e informal, assim como o ensino não formal, através de objectos históricos, espólios de museus, obras históricas e novas abordagens educacionais.</jats:p>

Abstract The incorporation of carbon-based nanomaterials into biopolymer matrix, to provide mechanical reinforcement and to obtain electrically conductive bionanocomposites, requires the homogeneous dispersion of the fillers. Herein, it is investigated the influence of surfactant structures on the dispersibility of multiwalled carbon nanotubes (MWNT) within starch matrix. Three different ionic surfactants, sodium dodecyl sulphate (SDS), cetyltrimethylammonium bromide (CTAB) and sodium cholate (SC), are employed to disperse the MWNT. Films with MWNT-SC show better dispersibility and an increase of about 75% of tensile strength and 60% of Young's modulus compared with films using MWNT-SDS and MWNT-CTAB. Nevertheless, MWNT functionalized with CTAB impart the highest values of antioxidant activity (scavenging activity around 30% in 1.5 h) and electrical conductivity (sigma =14.75 S/m) to starch matrix. The properties of starch-based films can be tailored according to the physical adsorption of each surfactant on MWNT surface and/or the interfacial interaction of the surfactant with starch chains.

Abstract Cationic polymer-DNA complexes, or polyplexes, have been subject to intensive investigation as potentially efficient non-viral systems for gene therapy. Yet the effects of ionic strength, a physiologically relevant parameter, on the formation, physicochemical properties (e.g. size and colloidal stability) and transfection efficiency of polyplexes are still poorly investigated and understood. In this work, we analyze the effect of ionic strength on the formation and transfection efficiency of poly-L-lysine (PLL), branched polyethylenimine (PEI) and bioreducible poly-L-Lysine (bPLL) polycations complexed with plasmid DNA, using different preparation paths. In path I, the polycation and DNA are mixed in water and transferred to saline media afterwards. In path II, the polycation and DNA are mixed already in the presence of salt. Despite that the final compositions are identical, for monovalent salt (NaCI) concentrations >= 70 mM, the two pathways give rise to polyplexes with different sizes and stability. Path I polyplexes are smaller and colloidally more stable than their path II analogues, irrespective of polycation. Regarding the different polycations used, PLL-DNA polyplexes are smaller and more stable than PEI-polyplexes, regardless of path, while bPLL-DNA particles aggregate very easily in saline media. Conversely, when applied to 2D A549 cell cultures, the two assembly pathways do not show significant differences in transfection efficiency, but regarding cellular-uptake, PEI and path I offer better results. Overall, we show that slight differences in ionic strength at the time of polyplex formation strongly influence the size and stability of polycation-DNA complexes, but they do not translate into significant differences in the transfection of 2D in vitro A549 cell-cultures. Notwithstanding, caution should be exercised as the size differences observed could impact transfection in more complex in vivo models.

Abstract In this paper, we draw upon the empirical research about the social representations of the Internet in order to propose a theoretically-driven agenda. A systematic review of empirical, peer-reviewed literature was conducted. The corpus of analysis consisted of 12 papers which fell into five themes: (i) the Internet and quality of life; (ii) the Internet as a moving representation; (iii) the Internet and ageing; (iv) the Internet and mobile culture; and (v) the Internet and education. The research about the social representations of the Internet is still limited in number, depth and breadth. Notwithstanding, it conveys important insights about the evolving, symbolically-loaded meanings of the Internet as a prosthesis of knowledge and as a means of communication, with consequences for identity and intergroup relations, contributing to expand the theoretical and empirical debates on the field of digital media. The research agenda for studying the Internet from a social representations’ perspective includes three major theoretical foci: social cognition; social identity and intergroup relations; and social thinking in times of big data. Social representations can provide the field with powerful conceptual tools to learn how people deal with novelty and to navigate through huge quantity of data generated online. In change, digital media can contribute to further social representations theory developments. To learn how communication flows on the Internet and how people make sense of the Internet and Internet-related phenomena (including automatically generated contents, mass and social media accounts) equals to set the clock for the present time schedule. © 2021. Moreira, Luciano, Paiva, João C. and Morais, Carla.

Abstract The COVID-19 pandemic situation has pushed many higher education institutions into a fast-paced, and mostly unstructured, emergency remote education process. In such an unprecedented context, it is important to understand how technology is mediating the educational process and how teachers and students are experiencing the change brought by the pandemic. This research aims to understand how the learning was mediated by technology during the early stages of the pandemic and how students and teachers experienced this sudden change. Data were collected following a qualitative research design. Thirty in-depth and semi-structured interviews (20 students and 10 teachers) were obtained and analysed following a thematic analysis approach. Results provide evidence on the adoption of remote education technologies due to the pandemic with impacts on the education process, ICT platforms usage and personal adaptation. The emergency remote education context led to mixed outcomes regarding the education process. Simultaneously, ICT platforms usage was mostly a positive experience and personal adaptation was mostly a negative experience. These results bring new insights for higher education organizations on actions they could take, such as curating the learning experience with standard, institutional-wide platforms, appropriate training for students and teachers, and suitable remote evaluation practices.

Abstract Non-viral gene therapy based on gene silencing with small interfering RNA (siRNA) has attracted great interest over recent years. Among various types of cationic complexation agents, amino acid-based surfactants have been recently explored for nucleic acid delivery due to their low toxicity and high biocompatibility. Monoolein (MO), in turn, has been used as helper lipid in liposomal systems due to its ability to form inverted nonbilayer structures that enhance fusogenicity, thus contributing to higher transfection efficiency. In this work, we focused on the development of nanovectors for siRNA delivery based on three gemini amino acid-based surfactants derived from serine - (12Ser)(2)N12, amine derivative; (12Ser)(2)COO12, ester derivative; and (12Ser)(2)CON12, amide derivative - individually combined with MO as helper lipid. The inclusion of MO in the cationic surfactant system influences the morphology and size of the mixed aggregates. Furthermore, the gemini surfactant:MO systems showed the ability to efficiently complex siRNA, forming stable lipoplexes, in some cases clearly depending on the MO content, without inducing significant levels of cytotoxicity. High levels of gene silencing were achieved in comparison with a commercially available standard indicating that these gemini:MO systems are promising candidates as lipofection vectors for RNA interference (RNAi)-based therapies.

Abstract <jats:p>An attitude is seen as a hypothetical construct related to a tendency expressed by evaluating a particular entity with some degree of favour or disfavour. In the case of attitudes toward science, these cannot be isolated from understanding science’s processes: the path to produce, refute, and change knowledge. Thus, it is critical to promote public engagement with science-astronomy and technology with the goal of understanding content, but also of understanding what science is and how it is built. In this context, CoAstro: @n Astronomy Condo emerged –a citizen science project starts with the engagement of primaryschool teachers with the Research Group on the “Origin and Evolution of Stars and Planets”at the Instituto de Astrofísica e Ciências do Espaço (IA). A semi-structured interview was conducted to study teachers' attitudes and epistemological beliefs towards science and the changes promoted by CoAstro. The interview was performed before and after the development of the CoAstro. It involved nine primary school teachers with no degree in science and who volunteered to participate in CoAstro. The results show that there has been an increase of interest in astronomy and the reinforcement of epistemological beliefs.</jats:p>

Abstract The promotion of positive attitudes towards science is an important goal of science education. This research aimed to identify students' attitudes towards science and whether their participation within a citizen science project has contributed to positive attitudinal changes. So, an attitudinal scale was developed, validated, and applied (as a pre and post-test) to 574 students aged between 12 and 14 years old. Positive attitudes towards science were recorded from the outset among children of both groups. Students' participation within the experimental group enhanced relevant positive attitudinal changes at the level of the critical analysis dimension, related to the perception of skills development such as questioning or critical thinking. Furthermore, positive attitudinal changes were achieved within the affinity dimension, related to perceived self-efficacy and appreciation of science and science classes. Positive attitudinal changes towards science among students indicate that citizen science contributes to enhance affective and attitudinal domains of their scientific literacy.

Abstract The development of composites from 1D and 2D nanocarbon building blocks, namely carbon nanotubes and graphene layers, with enhanced properties or novel functionalities is an emerging challenge in material science. Herein, we developed a colloid-based approach using surfactants and polymers to non-covalently functionalize multiwalled carbon nanotubes (MWNTs) and graphene nanoplatelets (GnPs), and to fabricate GnP@MWNT nanocomposites via an electrostatic-driven assembly process in aqueous solution. In the assembly process, two building methods were used and compared (bulk mixing and adapted layer-by-layer assembly), using surfactant and polymer/surfactant combinations as the dispersants for the initial nanomaterials. After their characterization by scanning electron microscopy, Raman spectroscopy and BET analysis, the nanocomposites were evaluated as electrocatalysts for the oxygen reduction reaction (ORR). Results show that the type of the dispersant (namely the presence of polymer) plays a more relevant role than the specific building method in almost all the ORR parameters. Further, the nanocomposites show selectivity toward the 2-electron pathway oxygen reduction for the electrochemical production of hydrogen peroxide. The development and optimization of further nanocomposite electrocatalysts can be pursued using this type of versatile and robust assembly method.

Abstract In this work, we explore the ability of newly synthesized threonine-derived surfactants to form robust, versatile and cytocompatible catanionic vesicles when mixed with gemini surfactants, as potential effective nanocarriers for biomolecules. The threonine surfactants consist of single-tailed amphiphiles with carboxylate headgroups and varying alkyl tail length, CnThr, where n is the (even) number of tail C atoms, varying from 8 to 16. After an initial characterization of the micellization behavior of the neat CnThr surfactants (at pH = 7 and 12), the dodecyl derivative, C12Thr, was selected as the optimal surfactant to investigate regions of formation of spontaneous catanionic vesicles. Phase behavior studies and microstructural characterization of mixtures involving both conventional bis-quat n-s-n gemini (where n and s are the tail and spacer number of C atoms) and biocompatible serine-derived gemini surfactants were carried out. Light and electron microscopy, dynamic light scattering and zeta potential measurements show spontaneous vesicles indeed form and exhibit versatile features in terms of average size, morphology, polydispersity, surface charge and pH. The toxicological profile of the neat surfactants and C12Thr/gemini vesicles based on MTT assays with a L929 cell line was also evaluated, showing good levels of in vitro cytocompatibility. Overall, the assortment of developed catanionic vesicles offers very attractive physicochemical and biological features to be explored for delivery purposes.