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2023
Silva, Ana B. P., Ana R. Jesus, Daniela A. S. Agostinho, José M. S. S. Esperança, Alexandre Paiva, Ana R. C. Duarte, and Patrícia M. Reis. "Using dicationic ionic liquids to upgrade the cytotoxicity and solubility of poorly water-soluble drugs." 3.1 (2023): 100052. AbstractWebsite

New dicationic ionic liquids (DcILs) based on carboxylic acid-derived, N-acetyl amino acid-derived or bromide anions, and ammonium cations were synthesized and characterized. DcILs were employed as co-solvents to improve the solubility of ibuprofen and ketoprofen belonging to BCS class II. These DcILs demonstrated to be less cytotoxic towards fibroblasts L929 cells and contributed to an augment in the solubility of both drugs when compared with monocationic ionic liquids (McILs). The cytotoxic profile of some of these ILs was established, and when the linker between two ammonium cations was an ether group or a short alkyl chain an IC50 higher than 200 mM for fibroblasts L929 cells was achieved. The anion structure showed to be a key factor in the solubility of both drugs, being the family of carboxylic acid-derived, the one that presented the most significant effect, followed by N-acetyl amino acid-derived and finally bromide. The two dimensional 1H1H– NOESY NMR spectra showed the interaction between the IL and the two oral drugs, responsible for the improvement of their solubility. The lipophilicity (logP) of ibuprofen and ketoprofen reduced in the presence of these new DcILs.

Pinheiro, Daniel, Pedro Amaro, Jorge Machado, Mauro Guerra, and José Paulo Santos. "Angular distribution of characteristic X-rays following electron impact ionization." Radiation Physics and Chemistry. 203 (2023). Abstract

In this paper, we present a theoretical study of the X-ray fluorescence emission after vacancy of K-shell due to electron impact ionization. In particular, we focus on the angular distributions of the characteristic Kα emission lines following this process. Rh was chosen for the analysis since it is a common element in X-ray tube anodes. In this analysis we also considered some elements along the period-4, i.e., Ni, Cu and Co as case-studies. In doing so, we studied the magnetic sub-level population of the ionized states, which is directly related to the angular distribution of the emission. A relative low angular distribution for the Kα emission of Rh of 0.5% was observed, which makes the assumption of isotropic emission correct for most studies. Moreover, a comparison with the respective angular emission for adjacent elements in the fourth period of the periodic table shows that this isotropy is attributed to a small total angular momentum of the resulting configurations after ionization, as well as to opposite angular distributions of the various transitions, which average to a maximum of 0.7% angular asymmetry in Ni.

Pinheiro, Daniel, André Fernandes, César Godinho, Jorge Machado, Gonçalo Baptista, Filipe Grilo, Luís Sustelo, Jorge M. Sampaio, Pedro Amaro, Roberta G. Leitão, José P. Marques, Fernando Parente, Paul Indelicato, Miguel de Avillez, José Paulo Santos, and Mauro Guerra. "K- and L-shell theoretical fluorescence yields for the Fe isonuclear sequence." Radiation Physics and Chemistry. 203 (2023): 110594. Abstract

In this work, we present K- and L- shell fluorescence yield values of the full isonuclear sequence of Fe ions, using a state-of-the-art multiconfiguration Dirac–Fock approach. These results may be of importance for spectral fitting and plasma modeling, both in laboratory and astrophysical studies, where Fe is an important benchmark element. The K-shell fluorescence yields were found to be very similar up to the removal of 14 electrons.

Moniz, António B., Marta Candeias, and Nuno Boavida. "Artificial Generative Intelligence and Work – Portugal." Generative Artificial Intelligence – Opportunities, Risks, and Policy Challenges. Eds. Bjørn Bedsted, Nicklas Bang Bådum, Reinhard Grünwald, Steffen Albrecht, Tore Tennøe, Ferran Domínguez, and Clara Marsan. Barcelona: EPTA, 2023. 70-77.report_en_2.pdf
Moniz, António B., Nuno Boavida, Csaba Makó, Bettina-Johanna Krings, and Pablo Sanz de Miguel. "Conclusion: Where is worker representation going? Diverse pathways for platform workers' collective strategies." Digital labour platforms: Representing workers in Europe . Eds. A. B. Moniz, and et al. Famalicão: Humus/CICS.NOVA, 2023. 231-244.
Moniz, António B., and Nuno Boavida. "Contextualising digital platform work in Portugal." Digital labours platforms: Representing workers in Europe. Eds. A. B. Moniz, and et al. Famalicão: Humus/CICS.NOVA, 2023. 29-34.
Moniz, António B., Nuno Boavida, Csaba Makó, Bettina Krings, and Pablo Sanz de Miguel. "Introduction." Digital labours platforms: Representing workers in Europe. Eds. A. B. Moniz, and et al. Famalicão: Humus/CICS.NOVA, 2023. 1-6.
de Miguel, Pablo Sanz, Juan Arasanz, António B. Moniz, and Nuno Boavida. "Revitalización sindical y nuevo sindicalismo en el capitalismo de plataformas: una comparación de los casos de España y Portugal en el sector del reparto digital." Empiria. Revista de metodología de ciencias sociales.59 (2023): 53-79. AbstractWebsite

The emergence of the platform economy is the most recent model of outsourcing practices and the flexibilization of the organisation of production supported by the development of information and communication technologies. The spread of this business model has led to the expansion of different precarious forms of employment, the most common being the bogus self-employed. The business model based on digital platforms also has the effect of limiting the capacity of trade unions to represent and defend workers, preventing or limiting, for example, resource to collective bargaining. This article compares the trade union revitalisation strategies deployed in Spain and Portugal in the rider sector by traditional trade unions and associations of delivery workers and precarious workers. The article shows how, in both countries, unions have combined organising and mobilisation strategies with actions aimed at influencing political and regulatory expectations. However, there is evidence of a greater experimentation of practices in the Spanish case, as well as a greater impact and influence of their strategies in political terms. The article also reveals important differences between the two countries regarding the relationship between traditional trade unions and delivery workers' associations.

Carvalho, Fernanda, Maria Margarida R. .A. . Lima, Elissavet Kavoulaki, Nuno Leal, Joaquim Simão, CARLOS GALHANO, Hugo Águas, Giuseppina Padeletti, and João Pedro Veiga. "Decay products of historical cements from the Palace of Knossos, Crete, Greece." Journal of Cultural Heritage. 64 (2023): 113-119. AbstractWebsite

The Palace of Knossos, located on the island of Crete, Greece, is one of Europe's most important archaeological sites, serving as a testament to the Minoan civilization. Situated near the Mediterranean Sea, it is in close proximity to the seaport, airport, and industrial areas. Decay products commonly found in historical monuments within or near urban areas, such as black crusts and salt efflorescence, are also prevalent at the Palace of Knossos. To better understand the characteristics of the type of deterioration compounds found on cement in historical reconstruction zones, as well as their possible relationship with factors influencing the deterioration process, a multi-analytical approach was designed for the study of these materials. The results indicate that the black crusts primarily consist of gypsum and carbonaceous matter. However, the efflorescence salts are predominantly composed of thenardite instead of halite, despite the palace's proximity to the coastal area. These results may contribute to ongoing and future maintenance and preservation efforts for the monument.

Bento Rebelo, H., B. Assunção, C. Bedon, and F. Amarante dos Santos. "Exploratory study on the use of bi-stable supports for the impact protection of point-fixed glazing systems." International Journal of Protective Structures (2023). AbstractWebsite
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Vicente da Silva, M., and A. N. Antão. "A new Hoek-Brown-Matsuoka-Nakai failure criterion for rocks." International Journal of Rock Mechanics and Mining Sciences. 172 (2023): 105602. AbstractWebsite

In the current paper, we propose a new three-dimensional strength criterion for rocks expressed in terms of the first principal stress invariant, I1, and the second and third invariants of the deviatoric stress tensor, J2 and J3. The design of this constitutive model conjugates the characteristics of two of the most well-known and widely used criteria in geotechnical engineering: Hoek-Brown and Matsuoka-Nakai. Its material parameters can be calibrated based on conventional axisymmetric compression and extension tests. Experimental polyaxial test data from a dozen different rock types were used to validate the current criterion.

Gonçalves, Rodrigo, David Henriques, Armando Antão, and Manuel Ritto-Corrêa. "On non-uniform plastic torsion of steel I-section cantilevers." Thin-Walled Structures. 187 (2023): 110731. AbstractWebsite

This paper aims at contributing towards a better understanding of the non-uniform elastoplastic torsion mechanism of I-section beams. The particular case of cantilevers subjected to an end torque is analysed, which constitutes a simple yet interesting problem, since the maximum torque is very close to the so-called Merchant upper bound (MUB), with added independent maximum bishear and Saint-Venant torques. Consequently, it turns out that the maximum torque can be significantly higher than that for uniform plastic torsion. Besides the MUB, several solutions are presented and compared, namely (i) a stress resultant-based solution stemming from the warping beam theory differential equilibrium equation and (ii) solutions obtained with several beam finite elements that allow for a coarse/refined description of warping. It is found that all models are in very close agreement in terms of maximum torque (including the MUB) and stress resultants. However, the beam finite elements that allow for bishear, even with a simplified warping function, are further capable of reproducing quite accurately the stress field, as a comparison with a 3D solid finite element solution shows. Although the paper is primarily concerned with the small displacement case, the influence of considering finite rotations is also addressed.

Santos, I. M., M. Alexandre, V. D. Mihailetchi, J. A. Silva, T. Mateus, A. Mouquinho, J. Boane, A. T. Vicente, D. Nunes, U. D. Menda, H. Águas, E. Fortunato, R. Martins, and MJ Mendes. "Optically-Boosted Planar IBC Solar Cells with Electrically-Harmless Photonic Nanocoatings." Advanced Optical Materials. 11 (2023). AbstractWebsite
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Pinheiro, A., A. Ruivo, J. Rocha, M. Ferro, JV Pinto, J. Deuermeier, T. Mateus, A. Santa, MJ Mendes, R. Martins, S. Gago, C. A. T. Laia, and H. Águas. "Parylene-Sealed Perovskite Nanocrystals Down-Shifting Layer for Luminescent Spectral Matching in Thin Film Photovoltaics." Nanomaterials. 13 (2023). AbstractWebsite
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Duarte, Marlene, Victor D. Alves, Márcia Correia, Catarina Caseiro, Luís M. A. Ferreira, Maria João Romão, Ana Luísa Carvalho, Shabir Najmudin, Edward A. Bayer, Carlos M. G. A. Fontes, and Pedro Bule. "Structure-function studies can improve binding affinity of cohesin-dockerin interactions for multi-protein assemblies." International Journal of Biological Macromolecules. 224 (2023): 55-67. AbstractWebsite

The cellulosome is an elaborate multi-enzyme structure secreted by many anaerobic microorganisms for the efficient degradation of lignocellulosic substrates. It is composed of multiple catalytic and non-catalytic components that are assembled through high-affinity protein-protein interactions between the enzyme-borne dockerin (Doc) modules and the repeated cohesin (Coh) modules present in primary scaffoldins. In some cellulosomes, primary scaffoldins can interact with adaptor and cell-anchoring scaffoldins to create structures of increasing complexity. The cellulosomal system of the ruminal bacterium, Ruminococcus flavefaciens, is one of the most intricate described to date. An unprecedent number of different Doc specificities results in an elaborate architecture, assembled exclusively through single-binding-mode type-III Coh-Doc interactions. However, a set of type-III Docs exhibits certain features associated with the classic dual-binding mode Coh-Doc interaction. Here, the structure of the adaptor scaffoldin-borne ScaH Doc in complex with the Coh from anchoring scaffoldin ScaE is described. This complex, unlike previously described type-III interactions in R. flavefaciens, was found to interact in a dual-binding mode. The key residues determining Coh recognition were also identified. This information was used to perform structure-informed protein engineering to change the electrostatic profile of the binding surface and to improve the affinity between the two modules. The results show that the nature of the residues in the ligand-binding surface plays a major role in Coh recognition and that Coh-Doc affinity can be manipulated through rational design, a key feature for the creation of designer cellulosomes or other affinity-based technologies using tailored Coh-Doc interactions.

Ribeiro, G., G. Ferreira, U. D. Menda, M. Alexandre, M. J. Brites, M. A. Barreiros, S. Jana, H. Águas, R. Martins, P. A. Fernandes, P. Salomé, and MJ Mendes. "Sub-Bandgap Sensitization of Perovskite Semiconductors via Colloidal Quantum Dots Incorporation." Nanomaterials. 13 (2023). AbstractWebsite
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Menda, U. D., G. Ribeiro, J. Deuermeier, E. López, D. Nunes, S. Jana, I. Artacho, R. Martins, I. Mora-Seró, MJ Mendes, and I. Ramiro. "Thermal-Carrier-Escape Mitigation in a Quantum-Dot-In-Perovskite Intermediate Band Solar Cell via Bandgap Engineering." ACS Photonics. 10 (2023): 3647-3655. AbstractWebsite
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Vicente da Silva, M., and A. N. Antão. "Three-dimensional Limit Analysis using the Extended-Matsuoka–Nakai yield criterion." Computers and Geotechnics. 161 (2023): 105526. AbstractWebsite

This paper investigates the implementation of the Extended-Matsuoka–Nakai yield criterion on a strict Limit Analysis finite element formulation. The current approach is based on a three-field mixed finite element model and the Alternating Direction Method of Multipliers optimization algorithm. With the support of duality principles two variants are derived, the lower bound and the upper bound element. The main novelty of this work is the development of an efficient iterative predictor–corrector scheme, customized for the Extended-Matsuoka–Nakai. This scheme is an indispensable requirement for this formulation. To conclude four numerical examples are presented to assess the effectiveness and efficiency of the numerical tool.

Santana, T., A. Antão, N. Guerra, and M. Vicente da Silva. "Upper bounds for the three-dimensional seismic active earth pressure coefficients." Géotechnique Letters. 13 (2023): 65-74. AbstractWebsite

A numerical implementation of the upper-bound theorem of limit analysis is applied to determine two-dimensional (2D) and three-dimensional (3D) active horizontal earth pressure coefficients considering seismic actions through a horizontal seismic coefficient. Results are obtained for vertical wall, horizontal soil, different friction angles of the soil, soil-to-wall friction ratios, horizontal seismic coefficients and wall width-to-height ratios. The few cases for which 3D active earth pressure coefficients are available in the literature using upper-bound methods were used for comparison with the corresponding earth pressure coefficients obtained in this study. This showed a general improvement of these results, which allows expecting a good accuracy for the set of cases studied. The ratios between the 3D and 2D horizontal active earth pressure coefficients are found to be practically independent of the soil-to-wall friction ratio. An equation is proposed for calculating these ratios. This equation can be easily used in the design of geotechnical structures requiring the determination of 3D active earth pressure coefficients.

2022
Amaro, P., A. Adamczak, Abdou M. Ahmed, L. Affolter, F. D. Amaro, P. Carvalho, T. L. Chen, L. M. P. Fernandes, M. Ferro, D. Goeldi, T. Graf, M. Guerra, T. W. Hänsch, C. A. O. Henriques, Y. C. Huang, P. Indelicato, O. Kara, K. Kirch, A. Knecht, F. Kottmann, Y. W. Liu, J. Machado, M. Marszalek, R. D. P. Mano, C. M. B. Monteiro, F. Nez, J. Nuber, A. Ouf, N. Paul, R. Pohl, E. Rapisarda, J. M. F. dos Santos, J. P. Santos, P. A. O. C. Silva, L. Sinkunaite, J. T. Shy, K. Schuhmann, S. Rajamohanan, A. Soter, L. Sustelo, D. Taqqu, L. B. Wang, F. Wauters, P. Yzombard, M. Zeyen, and A. Antognini. "Laser excitation of the 1s-hyperfine transition in muonic hydrogen." SciPost Physics. 13 (2022). Abstract

The CREMA collaboration is pursuing a measurement of the ground-state hyperfine splitting (HFS) in muonic hydrogen (μp) with 1 ppm accuracy by means of pulsed laser spectroscopy to determine the two-photon-exchange contribution with 2×10-4 relative accuracy. In the proposed experiment, the μp atom undergoes a laser excitation from the singlet hyperfine state to the triplet hyperfine state, then is quenched back to the singlet state by an inelastic collision with a H2 molecule. The resulting increase of kinetic energy after the collisional deexcitation is used as a signature of a successful laser transition between hyperfine states. In this paper, we calculate the combined probability that a μp atom initially in the singlet hyperfine state undergoes a laser excitation to the triplet state followed by a collisional-induced deexcitation back to the singlet state. This combined probability has been computed using the optical Bloch equations including the inelastic and elastic collisions. Omitting the decoherence effects caused by the laser bandwidth and collisions would overestimate the transition probability by more than a factor of two in the experimental conditions. Moreover, we also account for Doppler effects and provide the matrix element, the saturation fluence, the elastic and inelastic collision rates for the singlet and triplet states, and the resonance linewidth. This calculation thus quantifies one of the key unknowns of the HFS experiment, leading to a precise definition of the requirements for the laser system and to an optimization of the hydrogen gas target where μp is formed and the laser spectroscopy will occur.

Cardoso, João, Patrícia Almeida, Gonçalo Catatão, Guilherme Cândida, Frederico Páscoa, Daniela Silva, Carla Machado, João P. Borges, and Alexandre Velhinho. "Designing Structural Metamaterials." 8.1 (2022): 55. Abstract
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Simões, Beatriz T., Filipe V. Almeida, João Paulo Borges, and Paula I. P. Soares. "Extracellular Hyperthermia for the Treatment of Advanced Cutaneous Melanoma." 8.1 (2022): 56. Abstract
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Almeida, Martim, Helena Mouriño, Arnaldo Batista, Sara Russo, Filipa Esgalhado, Catarina Palma R. dos Reis, Fátima Serrano, and Manuel Ortigueira. "Electrohysterography extracted features dependency on anthropometric and pregnancy factors." Biomedical Signal Processing and Control. 75 (2022).