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2016
Aroso, Ivo M., João C. Silva, Francisca Mano, Ana S. D. Ferreira, Madalena Dionísio, Isabel Sá-Nogueira, Susana Barreiros, Rui L. Reis, Alexandre Paiva, and Ana Rita C. Duarte. "{Dissolution enhancement of active pharmaceutical ingredients by therapeutic deep eutectic systems}." European Journal of Pharmaceutics and Biopharmaceutics. 98 (2016): 57-66. AbstractWebsite

A therapeutic deep eutectic system (THEDES) is here defined as a deep eutectic solvent (DES) having an active pharmaceutical ingredient (API) as one of the components. In this work, THEDESs are proposed as enhanced transporters and delivery vehicles for bioactive molecules. THEDESs based on choline chloride (ChCl) or menthol conjugated with three different APIs, namely acetylsalicylic acid (AA), benzoic acid (BA) and phenylacetic acid (PA), were synthesized and characterized for thermal behaviour, structural features, dissolution rate and antibacterial activity. Differential scanning calorimetry and polarized optical microscopy showed that ChCl:PA (1:1), ChCl:AA (1:1), menthol:AA (3:1), menthol:BA (3:1), menthol:PA (2:1) and menthol:PA (3:1) were liquid at room temperature. Dissolution studies in PBS led to increased dissolution rates for the APIs when in the form of THEDES, compared to the API alone. The increase in dissolution rate was particularly noticeable for menthol-based THEDES. Antibacterial activity was assessed using both Gram-positive and Gram-negative model organisms. The results show that all the THEDESs retain the antibacterial activity of the API. Overall, our results highlight the great potential of THEDES as dissolution enhancers in the development of novel and more effective drug delivery systems.

Morawiec, S., J. Holovský, MJ Mendes, M. Müller, K. Ganzerová, A. Vetushka, M. Ledinský, F. Priolo, A. Fejfar, and I. Crupi. "{Experimental quantification of useful and parasitic absorption of light in plasmon-enhanced thin silicon films for solar cells application}." Scientific Reports (2016). AbstractWebsite
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Antognini, A., K. Schuhmann, F. D. Amaro, P. Amaro, M. Abdou-Ahmed, F. Biraben, T. L. Chen, D. S. Covita, A. J. Dax, M. Diepold, L. M. P. Fernandes, B. Franke, S. Galtier, A. L. Gouvea, J. Götzfried, T. Graf, T. W. Hänsch, M. Hildebrandt, P. Indelicato, L. Julien, K. Kirch, A. Knecht, F. Kottmann, J. J. Krauth, Y. W. Liu, J. Machado, C. M. B. Monteiro, F. Mulhauser, F. Nez, J. P. Santos, J. M. F. dos Santos, C. I. Szabo, D. Taqqu, J. F. C. A. Veloso, A. Voss, B. Weichelt, and R. Pohl. "{Experiments towards resolving the proton charge radius puzzle}." Vol. 113. EPJ Web of Conferences, 2016. 01006. Abstract
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Silva, João C., Alexandre A. Barros, Ivo M. Aroso, Dario Fassini, Tiago H. Silva, Rui L. Reis, and Ana Rita C. Duarte. "{Extraction of Collagen/Gelatin from the Marine Demosponge Chondrosia reniformis (Nardo, 1847) Using Water Acidified with Carbon Dioxide - Process Optimization}." Industrial and Engineering Chemistry Research. 55 (2016): 6922-6930. Abstract

Marine sponges are a rich source of natural bioactive compounds. One of the most abundant valuable products is collagen/gelatin, which presents an interesting alternative source for pharmaceutical and biomedical applications. We have previously proposed an innovative green technology for the extraction of collagen/gelatin from marine sponges based in water acidified with carbon dioxide. In this work, we have optimized the process operating conditions toward high yields and collagen quality as well as to reduce extraction procedure duration and energy consumption. The process extraction efficiency is higher than 50{%}, corresponding to a yield of approximately 10{%} of the sponge dry mass, obtained for mild operating conditions of 10 bar and 3 h. The extracted material was characterized by scanning electron microscopy (SEM), rheology, Fourier transformed infrared spectroscopy (FTIR), circular dichroism (CD), amino acid analysis, and SDS-PAGE. The extracts were found to be composed of highly pure mixtures of co...

Lyubchyk, A., A. Vicente, P. U. Alves, B. Catela, B. Soule, T. Mateus, MJ Mendes, H. Águas, E. Fortunato, and R. Martins. "{Influence of post-deposition annealing on electrical and optical properties of ZnO-based TCOs deposited at room temperature}." Physica Status Solidi (A) Applications and Materials Science. 213 (2016). Abstract

© 2016 WILEY-VCH Verlag GmbH {&} Co. KGaA, Weinheim The post-deposition modification of ZnO-based transparent conductive oxides (TCOs) can be the key to produce thin films with optoelectronic properties similar to indium tin oxide (ITO), but at a much lower cost. Here, we present electro-optical results achieved for post-deposition annealing of Al–Zn–O (AZO), AZO:H, Ga–Zn–O:H (GZO:H), and Zn–O:H (ZNO:H) thin films deposited by RF sputtering at room temperature. These studies comprise results of thermal annealing at atmospheric pressure, vacuum, forming gas, H2and Ar atmospheres, and H2and Ar plasmas, which lead to significant enhancement of their electro-optical properties, which are correlated to morphological and structural improvements. The post-deposition annealing leads to an enhancement in resistivity above 40{%} for AZO, AZO:H, and GZO:H, reaching $\rho$ ≈ 2.6–3.5 × 10−4$Ømega$cm, while ZnO:H showed a lower improvement of 13{%}. The averaged optical transmittance in the visible region is about 89{%} for the investigated TCOs. Such results match the properties of state-of-art ITO ($\rho$ ≈ 10−4$Ømega$cm and transmittance in VIS range of 90{%}) employing much more earth-abundant materials.

Araujo, Andreia, Manuel J. Mendes, Tiago Mateus, Antonio Vicente, Daniela Nunes, Tomas Calmeiro, Elvira Fortunato, Hugo Aguas, and Rodrigo Martins. "{Influence of the Substrate on the Morphology of Self-Assembled Silver Nanoparticles by Rapid Thermal Annealing}." Journal of Physical Chemistry C (2016). AbstractWebsite
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Lyubchyk, Andriy, António Vicente, Bertrand Soule, Pedro Urbano Alves, Tiago Mateus, Manuel J. Mendes, Hugo Águas, Elvira Fortunato, and Rodrigo Martins. "{Mapping the Electrical Properties of ZnO-Based Transparent Conductive Oxides Grown at Room Temperature and Improved by Controlled Postdeposition Annealing}." Advanced Electronic Materials. 2 (2016): 1500287. AbstractWebsite

Indium tin oxide (ITO) is the current standard state-of-the-art transparent conductive oxide (TCO), given its remarkable optical and electrical properties. However, the scarcity of indium carries an important drawback for the long-term application due to its intensive use in many optoelectronic devices such as displays, solar cells, and interactive systems. Zinc oxide-based TCOs can be a cost-effective and viable alternative, but the limitations imposed by their transmittance versus resistivity tradeoff still keep them behind ITO. In this work, an in-depth study of the structural and compositional material changes induced by specific postannealing treatments is presented, based on aluminum zinc oxide (AZO) and hydrogenated AZO (AZO:H) thin films grown by rf-magnetron sputtering at room temperature that allows an extensive understanding of the films' electrical/structural changes and the ability to tune their physical parameters to yield increasingly better performances, which put them in line with the best ITO quality standards. The present investigation comprises results of thermal annealing at atmospheric pressure, vacuum, forming gas, H2 and Ar atmospheres and plasmas. Overall the study being performed leads to a decrease in resistivity above 40{%}, reaching $\rho$ ≈ 3 × 10−4 $Ømega$ cm, with an average optical transmittance in the visible region around 88{%}. Such results are equivalent to the properties of state-of-the-art ITO.

Reifarth, R., et al. "{Nuclear astrophysics with radioactive ions at FAIR}." Vol. 665. Journal of Physics: Conference Series, 2016. 012044. Abstract
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Nunes, D., A. Pimentel, JV Pinto, T. R. Calmeiro, S. Nandy, P. Barquinha, L. Pereira, P. A. Carvalho, E. Fortunato, and R. Martins. "{Photocatalytic behavior of TiO2 films synthesized by microwave irradiation}." Catalysis Today. 278 (2016). Abstract

© 2015 Elsevier B.V. Titanium dioxide was synthesized on glass substrates from titanium (IV)isopropoxide and hydrochloride acid aqueous solutions through microwave irradiation using as seed layer either fluorine-doped crystalline tin oxide (SnO2:F) or amorphous tin oxide (a-SnOx). Three routes have been followed with distinct outcome: (i) equimolar hydrochloride acid/water proportions (1HCl:1water) resulted in nanorod arrays for both seed layers; (ii) higher water proportion (1HCl:3water) originated denser films with growth yield dependent on the seed layer employed; while (iii) higher acid proportion (3HCl:1water) hindered the formation of TiO2. X-ray diffraction (XRD) showed that the materials crystallized with the rutile structure, possibly with minute fractions of brookite and/or anatase. XRD peak inversions observed for the materials synthesized on crystalline seeds pointed to preferred crystallographic orientation. Electron diffraction showed that the especially strong XRD peak inversions observed for TiO2 grown from the 1HCl:3water solution on SnO2:F originated from a [001] fiber texture. Transmittance spectrophotometry showed that the materials with finer structure exhibited significantly higher optical band gaps. Photocatalytic activity was assessed from methylene blue degradation, with the 1HCl:3water SnO2:F material showing remarkable degradability performance, attributed to a higher exposure of (001) facets, together with stability and reusability.

2015
Kchaou, Omaya Bellaaj, Amin Sallem, Pedro Pereira, Mourad Fakhfakh, and Maria Helena Fino. "Multi-objective sensitivity-based optimization of analog circuits exploiting NSGA-II front ranking." Synthesis, Modeling, Analysis and Simulation Methods and Applications to Circuit Design (SMACD), 2015 International Conference on. Istanbul, Turkey 2015. 1-4. Abstract

This work deals with the multi-objective optimization of analog circuits by generating the Pareto front where elements are low sensitive to parameters' variations. NSGA-II is used for obtaining the non-dominated solutions. Richardson extrapolation technique is used for the in-loop optimization approach for computing partial derivatives and, thus, the solutions' sensitivity. NSGA-II Pareto fronts' intrinsic ranking is exploited for the generation of the new ‘low-sensitive’ Pareto front. The case of the optimal sizing of a CMOS voltage follower is considered to exemplify the proposed approach.

Picado, Ana, Susana M. Paixao, Liliana Moita, Luis Silva, Mario S. Diniz, Joana Lourenco, Isabel Peres, Luisa Castro, Jose Brito Correia, Joana Pereira, Isabel Ferreira, Antnio Pedro Alves Matos, Pedro Barquinha, and Elsa Mendonca. "A multi-integrated approach on toxicity effects of engineered TiO2 nanoparticles." Frontiers of Environmental Science & Engineering. 9 (2015): 793-803. AbstractWebsite
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Inácio, Micael M. G., André F. O. Almeida, Duarte M. V. Faria, Válter J. G. Lúcio, and António Pinho Ramos. "Punching of high strength concrete flat slabs without shear reinforcement." Engineering Structures. 103 (2015): 275-284. AbstractWebsite

The experimental research carried out to study the punching behavior of high strength concrete (HSC) flat slabs is reported in the present work. Three flat slab specimens were cast using HSC and another one with normal strength concrete (NSC), to be used as a reference slab. The HSC mix presented a compressive strength of about 130MPa, with a basalt coarse aggregate. The tested specimens were square with 1650mm side and 125mm thickness. The longitudinal reinforcement ratio varied between 0.94{%} and 1.48{%}. The experimental results show that the use of HSC led to a significant load capacity increase when compared with the reference model made with NSC. Furthermore, the experimental results also indicated that as the longitudinal reinforcement ratio increased, the punching capacity also increased. The results obtained in this set of experimental tests and others collected from the literature were compared with the code provisions by EC2, MC2010 and ACI 318-11.

Safari, L., J. P. Santos, P. Amaro, K. Jankala, and F. Fratini. "Analytical evaluation of atomic form factors: Application to Rayleigh scattering." Journal of Mathematical Physics. 56 (2015): 052105-9. AbstractWebsite
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Cardoso, T., P. Pereira, V. Fernaao Pires, and J. F. Martins. "Android-based m-learning remote system for mobile power quality assessment in large buildings with renewable energies." Power Engineering, Energy and Electrical Drives (POWERENG), 2015 IEEE 5th International Conference on. Riga, Latvia 2015. 431-434. Abstract

Power Quality is a generic term focusing on several issues, going from reliability to the quality of service provided by the energy supplier. It addresses limiting aspects such as harmonic distortion, flicker, sags, swells and transients... It is important for the students to understand the differences between the large amounts of events that fit into poor power quality category. Moreover it is important for them to analyze real time non-laboratory events. To provide this experience to the students this paper presents a remote m-learning experimental system where several types of poor power quality events can be tested. The developed system is based on a power quality analysis distributed network and can be remotely accessed from a remote computer or smart phones.

Barquinha, Pedro, Sonia Pereira, Luis Pereira, Pawel Wojcik, Paul Grey, Rodrigo Martins, and Elvira Fortunato. "Flexible and Transparent WO3 Transistor with Electrical and Optical Modulation." Advanced Electronic Materials. 1 (2015). AbstractWebsite
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Diepold, Marc, Luis M. P. Fernandes, Jorge Machado, Pedro Amaro, Marwan Abdou-Ahmed, Fernando D. Amaro, Aldo Antognini, François Biraben, Tzu-Ling Chen, Daniel S. Covita, Andreas J. Dax, Beatrice Franke, Sandrine Galtier, Andrea L. Gouvea, Johannes Götzfried, Thomas Graf, Theodor W. Hänsch, Malte Hildebrandt, Paul Indelicato, Lucile Julien, Klaus Kirch, Andreas Knecht, Franz Kottmann, Julian J. Krauth, Yi-Wei Liu, Cristina M. B. Monteiro, Françoise Mulhauser, Boris Naar, Tobias Nebel, François Nez, Jose Paulo Santos, Joaquim M. F. dos Santos, Karsten Schuhmann, Csilla I. Szabo, David Taqqu, João F. C. A. Veloso, Andreas Voss, Birgit Weichelt, and Randolf Pohl. "Improved x-ray detection and particle identification with avalanche photodiodes." Review of Scientific Instruments. 86 (2015): 053102-7. AbstractWebsite
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Farchi, Eitan, Robert M. Hierons, and João M. Lourenço. "Special issue on Testing, Analysis and Debugging of Concurrent Programs." Software Testing, Verification and Reliability. 25 (2015): 165-166. AbstractWebsite

This special issue concerns a range of issues related to the development of concurrent programs. This is an important topic, because many systems are now either multi-threaded or distributed, and it is well known that concurrency makes testing, analysis and debugging significantly more complicated. Essentially, the alternative interleavings of events can lead to different behaviours, and so any analysis, debugging or testing technique must consider these interleavings. The interest in this topic is reflected in the larger than normal issue, which contains five papers. The papers fall into three groups: we start with a paper on debugging, then have two on static analysis techniques and finally have two on testing. All papers were reviewed in the normal way.

Barquinha, Pedro, Sónia Pereira, LuÍs Pereira, Pawel Wojcik, Paul Grey, Rodrigo Martins, and Elvira Fortunato. "{Flexible and Transparent WO 3 Transistor with Electrical and Optical Modulation}." Advanced Electronic Materials. 1 (2015): n/a–n/a. AbstractWebsite
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Diepold, Marc, Luis M. P. Fernandes, Jorge Machado, Pedro Amaro, Marwan Abdou-Ahmed, Fernando D. Amaro, Aldo Antognini, Fran{\c c}ois Biraben, Tzu-Ling Chen, Daniel S. Covita, Andreas J. Dax, Beatrice Franke, Sandrine Galtier, Andrea L. Gouvea, Johannes Götzfried, Thomas Graf, Theodor W. Hänsch, Malte Hildebrandt, Paul Indelicato, Lucile Julien, Klaus Kirch, Andreas Knecht, Franz Kottmann, Julian J. Krauth, Yi-Wei Liu, Cristina M. B. Monteiro, Fran{\c c}oise Mulhauser, Boris Naar, Tobias Nebel, Fran{\c c}ois Nez, José Paulo Santos, Joaquim M. F. dos Santos, Karsten Schuhmann, Csilla I. Szabo, David Taqqu, João F. C. A. Veloso, Andreas Voss, Birgit Weichelt, and Randolf Pohl. "{Improved x-ray detection and particle identification with avalanche photodiodes}." Review of Scientific Instruments. 86 (2015): 053102. AbstractWebsite
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Bahubalindruni, Pydi Ganga, Vitor Grade Tavares, Pedro Barquinha, Candido Duarte, Nuno Cardoso, Pedro Guedes de Oliveira, Rodrigo Martins, and Elvira Fortunato. "a-GIZO TFT neural modeling, circuit simulation and validation." Solid-State Electronics. 105 (2015): 30-36. AbstractWebsite
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Faustino, Pedro, and Carlos Chastre. "Analysis of load–strain models for RC square columns confined with CFRP." Composites Part B: Engineering. 74 (2015): 23-41. AbstractWebsite

This article presents the comparison between 6 theoretical models of axially confined concrete columns with the experimental results of 7 tested columns of different authors. This study analysed the accuracy of 6 different confinement models for square columns taking into account the results of experimental tests on 7 RC columns confined with CFRP sheets with different dimensions and carried out by different authors. The profile of curves, the peak/failure values, the stress–strain and axial–to–lateral relations were studied to conclude which models show the best correlation with the experimental test results. Quantification of this deviation was carried out for key parameters. Some models predicted peak values with reasonable accuracy – Manfredi & Realfonzo, Campione & Miraglia, Lam & Teng, Pellegrino & Modena – although for the whole load–strain behaviour only the model of Faustino, Chastre & Paula seemed to be reasonably accurate in most cases.

Kiazadeh, Asal, Daniela Salgueiro, Rita Branquinho, Joana Pinto, Henrique L. Gomes, Pedro Barquinha, Rodrigo Martins, and Elvira Fortunato. "Operational stability of solution based zinc tin oxide/SiO2 thin film transistors under gate bias stress." Apl Materials. 3 (2015). AbstractWebsite
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Kiazadeh, Asal, Daniela Salgueiro, Rita Branquinho, Joana Pinto, Henrique L. Gomes, Pedro Barquinha, Rodrigo Martins, and Elvira Fortunato. "{Operational stability of solution based zinc tin oxide/SiO2 thin film transistors under gate bias stress}." APL Materials. 3 (2015): 062804. AbstractWebsite

In this study, we report solution-processed amorphous zinc tin oxide transistors exhibiting high operational stability under positive gate bias stress, translated by a recoverable threshold voltage shift of about 20{%} of total applied stress voltage. Under vacuum condition, the threshold voltage shift saturates showing that the gate-bias stress is limited by trap exhaustion or balance between trap filling and emptying mechanism. In ambient atmosphere, the threshold voltage shift no longer saturates, stability is degraded and the recovering process is impeded. We suggest that the trapping time during the stress and detrapping time in recovering are affected by oxygen adsorption/desorption processes. The time constants extracted from stretched exponential fitting curves are ≈106 s and 105 s in vacuum and air, respectively.

Ullaha, Sana, Fabio {De Matteis}, Rita Branquinho, Elvira Fortunato, Rodrigo Martins, and Ivan Davoli. "{A combination of solution synthesis {&} solution combustion synthesis for highly conducting and transparent Aluminum Zinc Oxide thin films}." 2015 IEEE 15th International Conference on Nanotechnology (IEEE-NANO). IEEE, 2015. 144-147. Abstract

Aluminum Zinc Oxide has been extensively investigated as a cheap alternative to transparent conducting tin oxide films for electronic and optoelectronic applications. Thin films of Aluminum Zinc Oxide have been developed successfully through a combination of solution combustion synthesis and solution synthesis. Zn(NO3)3·6H2O as metal source was dissolved in 2-methoxyethanol as solvent through combustion synthesis with Urea as fuel while dopant source of AlCl3·6H2O was mixed separately in solvent to avoid aluminum oxide formation in the films. Precursor solutions were obtained mixing Zn {&} Al separate solutions in 9:1, 8:2, and 7:3 ratios respectively with oxide, fuel and dopant concentrations of 0.5, 0.25, 0.1, and 0.05 M. The film stacks have been prepared through spin-coating with heating at 400°C for 10 minutes after each deposition to remove residuals and evaporate solvents. Thermal annealing in oven at 600°C for 1 hour followed by rapid thermal annealing at 500°C {&} 600°C first in vacuum and then in N2-5{%}H2 environment respectively for 10 minutes each reduced the resistivity of film stacks. Film stack with 10 layers for an average thickness of 0.5$μ$m gave the best Hall Effect resistivity of 3.2 × 10-2 $Ømega$-cm in the case of 0.5M solution with Zn:Al mixing ratio of 9:1 for RTA annealings at 600°C with an average total transparency of 80 {%} in the wavelength range of 400-1200 nm. The results show a clear trend that increasing the amount of ingredients resistivity could further be decreased.

Santos, Lidia, Daniela Nunes, Tomas Calmeiro, Rita Branquinho, Daniela Salgueiro, Pedro Barquinha, Luis Pereira, Rodrigo Martins, and Elvira Fortunato. "Solvothermal Synthesis of Gallium-Indium-Zinc-Oxide Nanoparticles for Electrolyte-Gated Transistors." Acs Applied Materials & Interfaces. 7 (2015): 638-646. AbstractWebsite
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