Showing: 10 from total: 2424 publications
1. Exploiting the potential of rivastigmine-melatonin derivatives as multitarget metal-modulating drugs for neurodegenerative diseases
Dias, I ; Bon, L ; Banas, A ; Chavarria, D ; Borges, F ; Guerreiro-Oliveira, C ; Cardoso, SM ; Sanna, D ; Garribba, E ; Chaves, S ; Santos, MA
in JOURNAL OF INORGANIC BIOCHEMISTRY, 2025, ISSN: 0162-0134,  Volume: 262, 
Article,  Indexed in: crossref, scopus, unpaywall, wos 
Abstract The multifaceted nature of the neurodegenerative diseases, as Alzheimer's disease (AD) and Parkinson's disease (PD) with several interconnected etiologies, and the absence of effective drugs, led herein to the development and study of a series of multi-target directed ligands (MTDLs). The developed RIV-IND hybrids, derived from the conjugation of an approved anti-AD drug, rivastigmine (RIV), with melatonin analogues, namely indole (IND) derivatives, revealed multifunctional properties, by associating the cholinesterase inhibition of the RIV drug with antioxidant activity, biometal (Cu(II), Zn(II), Fe(III)) chelation properties, inhibition of amyloid-/3 (A/3) aggregation (self- and Cu-induced) and of monoamine oxidases (MAOs), as well as neuroprotection capacity in cell models of AD and PD. In particular, two hybrids with hydroxyl-substituted indoles ( 5a2 and 5a3) ) could be promising multifunctional compounds that inspire further development of novel anti-neurodegenerative drugs.

2. LABORATORY ELECTROCHEMISTRY “MYSTERY BOX”: FROM PRE-SERVICE TEACHERS’ OBSERVATIONS TO INFERENCES THROUGH PREDICT-OBSERVE-EXPLAIN STRATEGY
Morais, C ; André, C ; Alves, J ; Girotto Jr., G
in Química Nova, 2025, ISSN: 0100-4042, 
Article,  Indexed in: crossref 
Abstract <jats:p>Given the challenges associated with understanding electrochemistry content by engaging in prediction, observation, and explanation, laboratory activities can foster active participation and critical thinking, enabling individuals to proactively confront and revise their understanding. Since pre-service teachers should gain firsthand experience with predict-observe-based on a predict-observe-explain strategy, we propose a laboratory activity presented as a “mystery box” related to concentration cells coupled with an Arduino-based electronic data measurement system to identify how pre-service chemistry teachers move from observations to inferences in a qualitative research. Data was collected by written records and oral explanations during the practical interactions. Results suggest that the proposed laboratory activity allows pre-service chemistry teachers to access data and correct inferences related to electrochemistry content, promoting critical thinking. Data also showed a connection between the macroscopic and symbolic domains, and pre-service teachers recognized concepts associated with the activity, such as solution conductivity and the potential difference in chemical reactions, interpreting the system with prior knowledge, like electron flow direction and concentration cell components. However, additional strategies are needed for detailed and consistent observation and inference recording, enhancing the potential of such activities in favoring electrochemistry education in high schools.</jats:p>

3. Investigation of the Chemiluminescent Reaction of a Fluorinated Analog of Marine Coelenterazine
Magalhaes, CM ; da Silva, JCGE ; da Silva, LP
in MATERIALS, 2024, ISSN: 1996-1944,  Volume: 17, 
Article,  Indexed in: crossref, scopus, wos 
Abstract Bioluminescence (BL) and chemiluminescence (CL) are remarkable processes in which light is emitted due to (bio)chemical reactions. These reactions have attracted significant attention for various applications, such as biosensing, bioimaging, and biomedicine. Some of the most relevant and well-studied BL/CL systems are that of marine imidazopyrazine-based compounds, among which Coelenterazine is a prime example. Understanding the mechanisms behind efficient chemiexcitation is essential for the optimization and development of practical applications for these systems. Here, the CL of a fluorinated Coelenterazine analog was studied using experimental and theoretical approaches to obtain insight into these processes. Experimental analysis revealed that CL is more efficient under basic conditions than under acidic ones, which could be attributed to the higher relative chemiexcitation efficiency of an anionic dioxetanone intermediate over a corresponding neutral species. However, theoretical calculations indicated that the reactions of both species are similarly associated with both electron and charge transfer processes, which are typically used to explain efficiency chemiexcitation. So, neither process appears to be able to explain the relative chemiexcitation efficiencies observed. In conclusion, this study provides further insight into the mechanisms behind the chemiexcitation of imidazopyrazinone-based systems.

4. Micro- and Nanoplastics in the Atmosphere: Methodology for Microplastics Size-Fractionation Sampling
Logvina, Y ; Matas, IM ; Ribeiro, H ; da Silva, LP ; Rodrigues, P ; Leitao, J ; da Silva, JE
in MICROPLASTICS, 2024, Volume: 3, 
Review,  Indexed in: crossref, wos 
Abstract Micro- and nanoplastics (MNPs) are an important atmospheric aerosol constituent. However, there still needs to be a standard procedure for their sampling and size fractionation, which is an obstacle to the aggregation and critical analysis of results obtained by different research groups. This review focuses on the sampling and fractionation methodologies used for MNPs. Moreover, a streamlined, simplified methodology for sampling and fractionation is proposed.

5. Sustainable Technological Applications of Green Carbon Materials
Freitas, M ; Pinto da Silva, L ; Rodrigues, P ; Silva, JEd
2024,
Unpublished,  Indexed in: crossref 
Abstract <jats:p>Green carbon-based materials (GCM), i.e. carbon materials produced using renewable biomass or recycled wastes, ought to be used in order to processes become sustainable and carbon neutral. Carbon nanomaterials, like for example carbon dots and nanobichar families, and carbon materials, like for example activated carbon and biochar substances, are sustainable materials with great potential to be used in different technology applications. In this review, the following four applications were selected, and the works published in the last two years (since 2022) critically reviewed: agriculture; water treatment; energy management; and, carbon dioxide reduction and sequestration. GCM improved the performance of the technological applications under revision and play an important role in the sustainability of the processes, contributing to the mitigation of the climate change, namely by reducing emission and increase sequestration of CO2eq..</jats:p>

6. Sustainable Technological Applications of Green Carbon Materials
Freitas, M ; da Silva, LP ; Rodrigues, PMSM ; da Silva, JE
in SUSTAINABLE CHEMISTRY, 2024, Volume: 5, 
Review,  Indexed in: authenticus, crossref, wos 
P-010-A4T
Abstract Green carbon-based materials (GCM), i.e., carbon materials produced using renewable biomass or recycled waste, ought to be used to make processes sustainable and carbon-neutral. Carbon nanomaterials, like carbon dots and the nanobichar families, and carbon materials, like activated carbon and biochar substances, are sustainable materials with great potential to be used in different technological applications. In this review, the following four applications were selected, and the works published in the last two years (since 2022) were critically reviewed: agriculture, water treatment, energy management, and carbon dioxide reduction and sequestration. GCM improved the performance of the technological applications under revision and played an important role in the sustainability of the processes, contributing to the mitigation of climate change, by reducing emissions and increasing the sequestration of CO2eq.

7. Mitochondria dysfunction induced by decyl-TPP mitochondriotropic antioxidant based on caffeic acid AntiOxCIN6 sensitizes cisplatin lung anticancer therapy due to a remodeling of energy metabolism
Amorim, R ; Magalhaes, CC ; Benfeito, S ; Cagide, F ; Tavares, LC ; Santos, K ; Sardao, VA ; Datta, S ; Cortopassi, GA ; Baldeiras, I ; Jones, JG ; Borges, F ; Oliveira, PJ ; Teixeira, J
in BIOCHEMICAL PHARMACOLOGY, 2024, ISSN: 0006-2952,  Volume: 219, 
Article,  Indexed in: crossref, scopus, wos 
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.

8. Mapping Travel Writing: A Critical Digital Humanities Perspective
Moreira, L ; Castanheira, MZ
in Digital Humanities Looking at the World: Exploring Innovative Approaches and Contributions to Society, 2024,
Book Chapter,  Indexed in: crossref, scopus, unpaywall 
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.

9. Thermodynamic Study of Alkylsilane and Alkylsiloxane-Based Ionic Liquids
Silva, RMA ; Montes-Campos, H ; Ferreira, AIMCL ; Bakis, E ; Santos, LMNBF
in JOURNAL OF PHYSICAL CHEMISTRY B, 2024, ISSN: 1520-6106,  Volume: 128, 
Article in Press,  Indexed in: crossref, scopus, unpaywall, wos 
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.

10. The Role of the Periodic Table of the Elements of Green and Sustainable Chemistry in a High School Educational Context
da Silva, CA Jr ; Morais, C ; de Jesus, DP ; Girotto, G Jr
in SUSTAINABILITY, 2024, ISSN: 2071-1050,  Volume: 16, 
Article,  Indexed in: crossref, scopus, unpaywall, wos 
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.