Publications

Abstract Carbon dots (CDs) are fluorescent carbon-based nanomaterials with remarkable properties, making them more attractive than traditional fluorophores. Consequently, researchers focused on their development and application in fields such as sensing and bioimaging. One potential advantage of employing CDs is using organic waste as carbon precursors in their synthesis, providing a pathway for waste upcycling for a circular economy. However, waste-based CDs often have low fluorescence quantum yields (QY(FL)), limiting their practical applications. So, there is a need for a well-defined strategy to consistently produce waste-based CDs with appreciable QY(FL), irrespective of the starting waste material. Herein, we developed a fabrication strategy based on the hydrothermal treatment of waste materials, using citric acid as a co-carbon precursor and ethylenediamine as N-dopant. This strategy was tested with various materials, including corn stover, spent coffee grounds, cork powder, and sawdust. The results showed consistently appreciable QY(FL), reaching up to similar to 40 %. A Life Cycle Assessment (LCA) study demonstrated that producing these waste-based CDs has lower environmental impacts compared to CDs made solely from commercial reagents. Thus, we have established a framework for the environmentally friendly production of CDs by upcycling different waste materials without significant sacrifices in performance (QY(FL)).

Abstract The pharmacological interest in mitochondria is very relevant since these crucial organelles are involved in the pathogenesis of multiple diseases, such as cancer. In order to modulate cellular redox/oxidative balance and enhance mitochondrial function, numerous polyphenolic derivatives targeting mitochondria have been developed. Still, due to the drug resistance emergence in several cancer therapies, significant efforts are being made to develop drugs that combine the induction of mitochondrial metabolic reprogramming with the ability to generate reactive oxygen species, taking into consideration the varying metabolic profiles of different cell types. We previously developed a mitochondria-targeted antioxidant (AntiOxCIN6) by linking caffeic acid to lipophilic triphenylphosphonium cation through a 10-carbon aliphatic chain. The antioxidant activity of AntiOxCIN6 has been documented but how the mitochondriotropic compound impact energy metabolism of both normal and cancer cells remains unknown. We demonstrated that AntiOxCIN6 increased antioxidant defense system in HepG2 cells, although ROS clearance was ineffective. Consequently, AntiOxCIN6 significantly decreased mitochondrial function and morphology, culminating in a decreased capacity in complex I-driven ATP production without affecting cell viability. These alterations were accompanied by an increase in glycolytic fluxes. Additionally, we demonstrate that AntiOxCIN6 sensitized A549 adenocarcinoma cells for CIS-induced apoptotic cell death, while AntiOxCIN6 appears to cause metabolic changes or a redox pre-conditioning on lung MRC-5 fibroblasts, conferring protection against cisplatin. We propose that length and hydrophobicity of the C10-TPP+ alkyl linker play a significant role in inducing mitochondrial and cellular toxicity, while the presence of the antioxidant caffeic acid appears to be responsible for activating cytoprotective pathways.

Abstract Travel writing reflects placed subjective human experience and participates in the collective processes of assembling stable, consensual, or polemical geographical entities and identities. In this chapter, we reflect on the contributions of Critical Digital Humanities to the communication of travel writing studies. Using R language, we are exploring the Anglophone Travelers in Portugal databases—which provide annotated information on almost 200 foreigner travel accounts in English published since the eighteenth century—to visualize geographical entities, analyze topics, and design visualization tools for non-expert audiences. In the process, four contributions of Critical Digital Humanities became evident. First, toponymical and semantic sources of ambiguity require us to develop a strong understanding of data as an artifact or capta (Drucker, Digital Humanities Quarterly, vol. 5, no. 1, pp. 1–21, 2011) construed in the annotating process that may affect the accuracy of automatic geocoding and processing based on named entity recognition. Critical digital humanist scholars, even if aware of such issues, lack creative solutions to express ambiguity as informative per se of the liquid nature of social labeling. Second, digital humanities open doors to enhanced interactivity (for instance, web applications) but require thoughtful, parsimonious solutions to express complexity which raises issues related to minimal computing (Risam and Gil, Digital Humanities Quarterly, vol. 16, no. 2, 2022). Third, Critical Digital Humanities helped to understand that communicating foreign perspectives may impact the audiences’ understanding of the traveled territory, but also of the travelers as an exogroup, a social category built on stereotyped views. Fourth, Critical Digital Humanities allowed us to better communicate the entangled nature of traveling and socio-historical circumstances. The challenge is to use such information to promote meaningful, centrifugal travel experiences rather than centripetal, massive travel itineraries. In the future, the project aims to grow via participatory citizen science (crowdsourcing) and to extend its scope to online digital sources related to travel (for instance, blogs). These new steps will foster the need to examine web scraping and text cleaning techniques and develop suitable storytelling approaches to engage people and create narratives that reflect their inputs in a critical way. © The Editor(s) (if applicable) and The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.

Abstract The thermodynamic properties of ionic liquids (ILs) bearing alkylsilane and alkylsiloxane chains, as well as their carbon-based analogs, were investigated. Effects such as the replacement of carbon atoms by silicon atoms, the introduction of a siloxane linkage, and the length of the alkylsilane chain were explored. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to study the thermal and phase behavior (glass transition temperature, melting point, enthalpy and entropy of fusion, and thermal stability). Heat capacity was obtained by high-precision drop calorimetry and differential scanning microcalorimetry. The volatility and cohesive energy of these ILs were investigated via the Knudsen effusion method coupled with a quartz crystal microbalance (KEQCM). Gas phase energetics and structure were also studied to obtain the gas phase heat capacity as well as the energy profile associated with the rotation of the IL side chain. The computational study suggested the existence of an intramolecular interaction in the alkylsiloxane-based IL. The obtained glass transition temperatures seem to follow the trend of chain flexibility. An increase of the alkylsilane chain leads to a seemingly linear increase in molar heat capacity. A regular increment of 30 JK-1mol(-1) in the molar heat capacity was found for the replacement of carbon by silicon in the IL alkyl chain. The alkylsilane series was revealed to be slightly more volatile than its carbon-based analogs. A further increase in volatility was found for the alkylsiloxane-based IL, which is likely related to the decrease of the cohesive energy due to the existence of an intramolecular interaction between the siloxane linkage and the imidazolium headgroup. The use of Si in the IL structure is a suitable way to significantly reduce the IL's viscosity while preserving its large liquid range (low melting point and high thermal stability) and low volatilities.

Abstract The Periodic Table of the Elements of Green and Sustainable Chemistry (PT-GSC) represents a potentially meaningful tool for teaching and learning Green Chemistry. However, there is a lack of studies exploring the application of the PT-GSC in educational contexts. To contribute to filling this gap, a qualitative and participant approach was developed to examine the effects of using the PT-GSC in a high school setting, with a focus on analyzing the associated challenges and opportunities. Over a five-week period, 23 high school students enrolled in a chemistry course at a public school in Brazil worked in small groups to develop solutions for a case study addressing socio-scientific issues related to water scarcity in the local region using elements from the PT-GSC. Results from both the pre- and post-questionnaires, along with the written case study resolutions, provide evidence of the students' knowledge gains, particularly in critical scientific literacy for Green and Sustainable Chemistry Education. The findings showed that the PT-GSC is an interdisciplinary tool for introducing students to Green Chemistry concepts within the broader societal and scientific ecosystem. The implementation of novel case studies incorporating elements from the PT-GSC is a way to support our ongoing work with students and the public, contributing to a sustainable future.

Abstract The Beer-Lambert law is a fundamental relationship in chemistry that helps connect macroscopic experimental observations (i.e., the amount of light exiting a solution sample) to a symbolic model composed of system-level parameters (e.g., concentration values). Despite the wide use of the Beer-Lambert law in the undergraduate chemistry curriculum and its applicability to analytical techniques, students' use of the model is not commonly investigated. Specifically, no previous work has explored how students connect the Beer-Lambert law to absorption phenomena using submicroscopic-level reasoning, which is important for understanding light absorption at the particle level. The incorporation of visual-conceptual tools (such as animations and simulations) into instruction has been shown to be effective in conveying key points about particle-level reasoning and facilitating connections among the macroscopic, submicroscopic, and symbolic domains. This study evaluates the extent to which a previously reported simulation-based virtual laboratory activity (BLSim) is associated with students' use of particle-level models when explaining absorption phenomena. Two groups of analytical chemistry students completed a series of tasks that prompted them to construct explanations of absorption phenomena, with one group having completed the simulation-based activity prior to the assessment tasks. Student responses were coded using Johnstone's triad. When comparing work from the two student groups, chi-square tests revealed statistically significant associations (with approximately medium to large effect sizes) between students using the simulation and employing particle-level reasoning. That said, submicroscopic-level reasoning did not always provide more explanatory power to students' answers. Additionally, we observed the productive use of a variety of submicroscopic light-matter interaction models. We conjecture that engaging with BLSim provided new submicroscopic-level resources for students to leverage in explanations and predictions of absorption phenomena.

Abstract Undergraduate arts and design programs have been incorporating computing education into their curricula. Through a documentation analysis of the first cycle (i.e., bachelor’s) curricula of fered by the Portuguese public education subsystem in the 2018-19 academic year, we identified 40 programs from diverse artistic and design areas, attended by around 5,600 students, which contained at least one course covering computer programming. In a subsequent qualitative analysis of the syllabi of those 128 courses we had identified as relevant, we characterized the objectives, the contents, and the teaching and assessment methods for computing in higher arts education. In the face of the skepticism the literature expresses regarding the validity and robustness of brief approaches to computing, we found most undergraduate programs dedicate few courses or credits (i.e., ECTS) to the topic. We also found programs that introduce the topic late in the curriculum, at a stage when it is likely to meet less dedication from the students. At course level, we note the prevalence of the objective of granting autonomous learning skills to students, which often translates into contents too broad to approach in a non-superficial way. Moreover, we alert to the use of project-based assessment methods in ways that do not assure learning of the contents. With this article we hope to provide an overview of the current situation and contribute to a reflection and a debate about the relevance and the way computing is covered within arts and design education. © (2024), (Emerson de Pietri). All Rights Reserved.

Abstract Activities with Parents on the Computer are pedagogical tasks based on socially relevant disciplinary content with the aim of establishing the school-home connection and collaboration between parents and students, to promote digital literacy and literacy in a specific domain. This article addresses a study that aimed to investigate the contribution of the Activity with Parents on the Computer "NanoAPC", both for the development of knowledge of 8th grade students about the area of nanotechnology, and to raise awareness among parents/guardians for the said area. The activities were proposed in a formal learning environment, the school, but were carried out at home by the student and one of the parents or guardian. NanoAPC intended to help students to learn Chemistry contents contextualized with the advances and applications of nanotechnology in society, from a socio-scientific perspective. A quasi-experimental research plan was implemented, with 58 students and 58 parents/guardians participating. Students were divided into two experimental conditions that were tested: groups 1 and 2, subject to NanoAPC, but with a different initial intervention, and group 3, subject to an activity sheet. All groups were subjected to a questionnaire as a pre-test and post-test, respectively before and after the intervention. The results, resulting from the analysis of the pre-test and post-test and the answers given in the respective activity sheets, show that the students in groups 1 and 2 showed a significant improvement in their knowledge of nanotechnology compared to those in group 3. We conclude that the NanoAPC digital resource is useful for teachers who show an interest in addressing nanotechnology but who have time constraints due to curriculum management. In addition, it promotes the parent-student-computer triangulation and, consequently, raises parents' awareness of this area. © 2024 Universidade Federal do Rio Grande do Sul, Instituto de Fisica. All rights reserved.

Abstract Nanocomposites have garnered attention for their potential as catalysts in electrochemical reactions vital for technologies like fuel cells, water splitting, and metal-air batteries. This work focuses on developing threedimensional (3D) nanocomposites through aqueous phase exfoliation, non-covalent functionalization of building blocks with surfactants and polymers, and electrostatic interactions in solution leading to the nanocomposites assembly and organization. By combining molybdenum disulfide (MoS2) layers with graphene nanoplatelets (GnPs) to form a binary 2D composite (MoS2/GnP), and subsequently incorporating multiwalled carbon nanotubes (MWNTs) to create ternary 3D composites, we explore their potential as catalysts for the oxygen reduction reaction (ORR) critical in fuel cells. Characterization techniques such as X-ray photoelectron spectroscopy, scanning electron microscopy, and X-ray diffraction elucidate material composition and structure. Our electrochemical studies reveal insights into the kinetics of the reactions and structure-activity relationships. Both the (MoS2/GnP)-to-MWNT mass ratio and nitrogen-doping of GnPs (N-GnPs) play a key role on the electrocatalytic ORR performance. Notably, the (MoS2/N-GnP)/MWNT material, with a 3:1 mass ratio, exhibits the most effective ORR activity. All catalysts demonstrate good long-term stability and methanol crossover tolerance. This facile fabrication method and observed trends offer avenues for optimizing composite electrocatalysts further.

Abstract Malaria is one of the big three global infectious diseases, having caused above two hundred million cases and over half a million deaths in 2020. The continuous demand for new treatment options prioritizes the cost-effective development of new chemical entities with multi-stage antiplasmodial activity, for higher efficacy and lower propensity to elicit drug-resistant parasite strains. Following up on our long-term research towards the rescue of classical antimalarial aminoquinolines like chloroquine and primaquine, we have developed new organic salts by acid-base pairing of those drugs with natural bile acids. These antimalarial drug-derived bile salts were screened in vitro against the hepatic, blood and gametocyte stages of Plasmodium parasites, unveiling chloroquine bile salts as unprecedented triple-stage antiplasmodial hits. These findings pave a new pathway for drug rescuing, even beyond anti-malarial and other anti-infective drugs. Malaria is one of the big three global infectious diseases, with the heaviest toll on human lives in low-to-middle income countries. Cost-effective antimalarial drugs with multi-stage action remain an unmet and urgent need in global healthcare.