Publications

Abstract <jats:p>The standard molar enthalpies of formation in the liquid phase for ethyl (E)-cinnamate and ethyl hydrocinnamate, two cinnamate derivatives with notable flavor and fragrance characteristics, were determined experimentally using combustion calorimetry in an oxygen atmosphere. To derive the gas-phase enthalpies of formation for these derivatives, their enthalpies of vaporization were measured using a high-temperature Calvet microcalorimeter and the vacuum drop microcalorimetric technique. Additionally, a computational analysis employing the G3(MP2)//B3LYP composite method was conducted to calculate the gas-phase standard enthalpies of formation at T = 298.15 K for both compounds. These findings enabled a detailed assessment and analysis of the structural and energetic effects of the vinyl and ethane moieties between the phenyl and carboxylic groups in the studied compounds. Considering the structural features of ethyl (E)-cinnamate and ethyl hydrocinnamate, a gas-phase enthalpy of hydrogenation analysis was conducted to explore their energetic profiles more thoroughly.</jats:p>

Abstract Integrating experimental activities with technological advancements and investigative pedagogies holds promise for fostering multifaceted development of chemical knowledge acquisition and innovative pedagogical methodologies for preservice teachers. This research evaluates how a laboratory activity on electrochemical concentration cells incorporating the Arduino system and implementing a Prediction-Observation-Explanation strategy improves chemical knowledge among preservice teachers. The study used a pretest assessing knowledge of galvanic cells, followed by evaluative questions during a course for preservice chemistry teachers. Preservice teachers had the opportunity to reflect on the module by commenting on issues related to implementing the activity and integrating the Arduino system. Difficulties are associated with understanding electrochemical cells and implementing the POE pedagogy. The study's results provide a basis for comments on the activity's adaptability and efficacy in the classroom and incorporation into a preservice teacher education curriculum.

Abstract A thermochemical study of 2-amino-1,3,4-thiadiazole, 2-amino-5-methyl-1,3,4-thiadiazole and 2-amino-5-ethyl-1,3,4-thiadiazole has been performed, aiming to establish possible correlations between energetic properties and structural characteristics of these compounds, as well as to assess to their thermodynamic stability. Calorimetric techniques (rotating bomb combustion calorimetry and Calvet microcalorimetry) complemented with a mass loss effusion method and computational calculations were used to determine the standard molar enthalpies of formation, in the gaseous phase, at T = 298.15 K, of the three thiadiazole derivatives. Theoretical calculations at the G3(MP2)//B3LYP level of theory were also performed to obtain the enthalpies of hypothetical reactions in the gaseous phase, as well as to calculate the gas-phase enthalpy of formation for the three thiadiazoles. From the two sets of results, it is possible to make a comparison between the experimental and computational values of the gas-phase enthalpy of formation. The standard Gibbs energies of formation in the crystalline and gaseous phases were also calculated, in order to evaluate the relative thermodynamic stability of the compounds. Additionally, a tautomeric analysis of the structure of each compound was performed, resulting in the establishment of a relationship between energy versus structure of the respective tautomeric forms.

Abstract A new library of non-nitrocatechol compounds (HetCAMs) was developed and their efficacy was compared to tolcapone, a standard COMT inhibitor for PD. Compound 9 emerged as the most potent inhibitor, showing selective inhibition of brain (IC50 = 24 nM) and liver (IC50 = 81 nM) MB-COMT over liver S-COMT (IC50 = 620 nM) isoforms. Although compound 9 presented higher IC50 values than tolcapone, it was more selective for brain MB-COMT than liver S-COMT. Unlike tolcapone, compound 9 is not a tight-binding inhibitor and is less cytotoxic to HepG2 and SK-N-SH cells. Additionally, compound 9 is predicted to cross the blood-brain barrier (BBB) by passive diffusion and chelate divalent metals like Fe(II) and Cu(II). The results demonstrate the potential of this rational drug design strategy for developing new CNS-active drug candidates, offering symptom relief via COMT inhibition that can provide a long-term, disease-modifying outcome (chelation of divalent metals) in PD.

Abstract New systems with innovative design to perform measurements combining electrochemistry and surface plasmon resonance (ESPR) are currently a need to overcome the limitations of existent market solutions and expand the research possibilities of this technology. The main goal of this work was to develop a new cell to increase ESPR practical applications in several fields. To do so, a homemade SPR cell, fabricated by 3D-printing technology, was adapted for this purpose by incorporating the conventional 3-electrodes to perform the electrochemical experiments. The developed cell was fully compatible with commercial SPR substrates. After optimization of the homemade ESPR setup to perform the combined electrochemical and SPR measurements, two main applications were explored in this work. The first was the use of ESPR technology as straightforward tool to simultaneously investigate the electrical and optical properties of conducing/non-conducting polymers electrosynthetized on the SPR platforms. The conducting polymer poly(thionine) was used in this work for proof-of-concept. The second application envisaged the use of ESPR approach for simple electrodeposition ofmaterials with enhanced plasmonic properties for sensitivity enhancement of SPR biosensors. For validation of the concept, graphene oxide (GO) was electrochemically reduced on gold substrates aiming to evaluate the plasmonic properties of graphene-modified sensing surfaces. © 2024 IEEE.

Abstract Aims Drug repurposing is an attractive strategy to control biofilm-related infectious diseases. In this study, two drugs (montelukast and cefoperazone) with well-established therapeutic applications were tested on Pseudomonas aeruginosa quorum sensing (QS) inhibition and biofilm control.Methods and results The activity of montelukast and cefoperazone was evaluated for Pqs signal inhibition, pyocyanin synthesis, and prevention and eradication of Ps. aeruginosa biofilms. Cefoperazone inhibited the Pqs system by hindering the production of the autoinducer molecules 2-heptyl-4-hydroxyquinoline (HHQ) and 2-heptyl-3-hydroxy-4(1H)-quinolone (the Pseudomonas quinolone signal or PQS), corroborating in silico results. Pseudomonas aeruginosa pyocyanin production was reduced by 50%. The combination of the antibiotics cefoperazone and ciprofloxacin was synergistic for Ps. aeruginosa biofilm control. On the other hand, montelukast had no relevant effects on the inhibition of the Pqs system and against Ps. aeruginosa biofilm.Conclusion This study provides for the first time strong evidence that cefoperazone interacts with the Pqs system, hindering the formation of the autoinducer molecules HHQ and PQS, reducing Ps. aeruginosa pathogenicity and virulence. Cefoperazone demonstrated a potential to be used in combination with less effective antibiotics (e.g. ciprofloxacin) to potentiate the biofilm control action.

Abstract Chronic wounds incidence is increasing and affects millions of people around the world, causing great psychological and socio-economic impacts. However, treatments that can effectively promote wound healing are still lacking. In this study, grape pomace (GP), the main residue from winemaking production was explored as a source of high added-value raw material directed for the topical treatment of Staphylococcus aureus chronic wound infections. Crude GP extracts (composed of stalks or a skin and seeds mixture–from red and white grape varieties) obtained using a modified solid-liquid extraction (water, ethanol, and acetone solvents) were evaluated for their antioxidant capacity (ABTS and DPPH assays), as well as the richness of phenolic compounds (total phenolic content-TPC, total flavonoid content-TFC, and HPLC-DAD assays). The GP extracts with the most favorable results were incorporated in a chitosan-alginate hydrogel (cross-linked with glutaraldehyde and calcium chloride), characterized (swelling, degradation, and release properties), and tested for its bioactivity (antioxidant and antimicrobial potential). TPC and TFC were higher in red GP extracts, as confirmed by the HPLC analysis, indicating a greater diversity of compounds in these extracts. Ethanolic white GP extracts (from skin-seeds mixture) showed the highest extraction yield and antioxidant activity. Their incorporation into the chitosan-alginate hydrogel improved its swelling and antimicrobial properties (total cytoplasmic membranes disruption and culturability reduction). A biomaterial with high swelling capacity and antibacterial activity against S. aureus was obtained, which can potentially promote wound healing by exudate absorption and infection clearance while promoting valorization of by-products and stimulating a circular economy. © 2024 The Authors

Abstract <jats:p>Manuel Simões was included as a corresponding author in the original publication [...]</jats:p>

Abstract The field of electrochemistry at the interface between two immiscible electrolyte solutions (ITIES) has been continuously expanding over the years due to their vast number of applications, including to investigate the partitioning of ionizable drugs at liquid-liquid systems. The aim of this Review is to highlight the great potential of ITIES as simple model of biological membranes to gather information on drug partition, lipophilicity, and pharmacokinetics that can be very useful for researchers in the field of drug discovery for development of new drugs with enhanced permeability. Relevant contributions and perspectives to improve the applicability of ITIES in partition studies were highlighted and discussed. The second part of this Review pretends to highlight the application of electrochemistry at the ITIES as experimental technique to investigate interactions between small ligands, including drugs, and DNA, a topic of high research interest in pharmaceutical and biological sciences, which remains with lots of opportunities to explore. Voltammetry at Liquid-Liquid Interfaces can be a versatile tool in the field of Drug Discovery as simple model for mimicking drug permeation through biological membranes helping to understand the partition of ionizable drugs between the aqueous and organic phases while providing fundamental information on its lipophilicity that can contribute to the design of new drugs with improved biological activity. image