Export 720 results:
Sort by: Author Title Type [ Year  (Desc)]
2017
Gomes da Silva, M, Pereira MMA, Franco R, Dionisio M, Ferreira LM, Branco P, Costa C, Lourenco A, Pereira AS, Mata P, Sotomayor J, Lima C, Vilarigues M, Parola AJ, Laia CAT, Coutinho IB, Branco L, Pereira C, Moro A, Gago S, Basilio N, Marques MM.  2017.  CHEMISTRY - AN EXPERIMENTAL SCIENCE. 9TH INTERNATIONAL CONFERENCE ON EDUCATION AND NEW LEARNING TECHNOLOGIES (EDULEARN17). (Chova, LG, Martinez, AL, Torres, IC, Eds.).:2548-2556. Abstract

In the last two decades, it has been observed an increasing low enrolment of students in chemistry teaching courses in secondary schools. On the one hand, because of the negative connotation of chemistry, associated with the potentially toxic and pollutant chemical industry, and on the other hand, that the teaching of this subject is exclusively carried out only in a theoretical classroom environment with almost non-existent practical/experimental component, despite chemistry is an experimental science in its essence. This state of affairs has been reflected in chemistry degrees offered by Portuguese universities throughout the country, which in the application process for each academic year, ended up by never completely fulfilling the number of offered nunerus clausus. Considering that the pedagogical mission of the Faculty of Science and Technology of Universidade NOVA de Lisboa (FCT-NOVA), in particular its Department of Chemistry (DQ), aims to contribute to the human, scientific and technical development of students, a project has been settled in the last nine years in order to offer to high school students a unique opportunity to arouse in them the interest in Science in general and Chemistry in particular, to stimulate impart on them the joy of curiosity, while at the same time conferring the necessary skills for their future activity as students of higher education or in the labour market. It is also through the close contact with students that method, discipline, and intellectual honesty are transmitted and cultivated. The aim of this Project was thus to promote the study and taste interest for Chemistry, through experimental activities, fitting the Portuguese High School Education curricula, offered to students enrolled in Chemistry subjects attending the 10th, 11th and 12th grades (the latter, compulsory high school degree to apply to University Throughout 2016/17 academic year, DQ-FCT-NOVA will receive, from October to May, 1888 students visits from eleven High Schools distributed among Physical Chemistry for 10th/11th grade and of the 12th grade attending the Chemistry subject. The former are offer one single laboratory activity while the latter participate up to 10 different experimental activities. During 70 practical sessions of 2.5 hours each, with an average attendance of 27 students, the number of higher education school staff involved are 22. Each high school class is accompanied by 1 teacher, who's also proactively contributing to the design of the practical session. The session is carried out in groups of 2/3 students, and the laboratories have a capacity of 24/48 according onto classes sizes. A quality questionnaire is filled by the students in order to monitor the action. In 2015/16, 63 % of the students answered the questionnaire in which more than 90% students were very satisfied with the action. This project has already been implemented for 9 years reflecting a growing collaboration between FCT-NOVA and in High Schools in the vicinity (Setubal District). Above all, this Project allowed most of these schools to continue to motivate students to enrol in 12th grade Chemistry subject. Actually, in the first year of the initiative, many of these schools did not have enough students to open chemistry classes for the 12th grade. After the first initiative, almost all high schools have been able to maintain open 12th grade chemistry classes. On the other hand, FCT-NOVA, namely, the Applied Chemistry course, has been able to fill 100% of the numerus clausus available in the first phase of the application period, which is not the case for other higher education schools courses in Portugal for the same domain - Chemistry.

Viveiros, R, Dias FM, Maia LB, Heggie W, Casimiro T.  2017.  Green strategy to produce large core–shell affinity beads for gravity-driven API purification processes. Journal of Industrial and Engineering Chemistry. 54:341-349. AbstractWebsite
n/a
Ferreira, MR, Dantas JM, Salgueiro CA.  2017.  Molecular interactions between Geobacter sulfurreducens triheme cytochromes and the electron acceptor Fe(iii) citrate studied by NMR. Dalton Trans.. 46:2350-2359.: The Royal Society of Chemistry AbstractWebsite

Proteomic and genetic studies have identified a family of five triheme cytochromes (PpcA-E) that are essential in the iron respiratory pathways of Geobacter sulfurreducens. These include the reduction of Fe(iii) soluble chelated forms or Fe(iii) oxides{,} which can be used as terminal acceptors by G. sulfurreducens. The relevance of these cytochromes in the respiratory pathways of soluble or insoluble forms of iron is quite distinct. In fact{,} while PpcD had a higher abundance in the Fe(iii) oxides supplanted G. sulfurreducens cultures{,} PpcA{,} PpcB and PpcE were important in Fe(iii) citrate supplanted cultures. Based on these observations we probed the molecular interactions between these cytochromes and Fe(iii) citrate by NMR spectroscopy. NMR spectra were recorded for natural abundance and 15N-enriched PpcA{,} PpcB or PpcE samples at increasing amounts of Fe(iii) citrate. The addition of this molecule caused pronounced perturbations on the line width of the protein{'}s NMR signals{,} which were used to map the interaction region between each cytochrome and the Fe(iii) citrate molecule. The perturbations on the NMR signals corresponding to the backbone NH and heme methyl substituents showed that complex interfaces consist of a well-defined patch{,} which surrounds the more solvent-exposed heme IV methyl groups in each cytochrome. Overall{,} this study provides for the first time a clear illustration of the formation of an electron transfer complex between Fe(iii) citrate and G. sulfurreducens triheme cytochromes{,} shown to be crucial in this respiratory pathway.

Faria, P, Duarte P, Barbosa D, Ferreira I.  2017.  New composite of natural hydraulic lime mortar with graphene oxide. Construction and Building Materials. 156:1150-1157. AbstractWebsite

Recent studies show the incorporation of graphene oxide (GO) in cement composites. But these composites are frequently incompatible with original materials for building rehabilitation. To overcome this limitation, natural hydraulic lime mortars were used as matrix, and the influence of GO percentage and type of mixing was investigated. The influence on the microstructure, mechanical and physical properties was assessed. The best results were obtained with dispersed GO at concentrations of 0.05% and 0.1%. A slight improvement of mechanical and physical characteristics was achieved. This could lead to new mortars with improved properties that can be used for building rehabilitation.

Figueira, J, Loureiro J, Marques J, Bianchi C, Duarte P, Ruoho M, Tittonen I, Ferreira I.  2017.  Optimization of Cuprous Oxides Thin Films to be used as Thermoelectric Touch Detectors. ACS Applied Materials & Interfaces. 9:6520-6529., Number 7 AbstractWebsite

The electronic and optical properties of p-type copper oxides (CO) strongly depend on the production technique as it influences the obtained phases: cuprous oxide (Cu2O) or cupric oxide (CuO), the most common ones. Cu films deposited by thermal evaporation have been annealed in air atmosphere, with temperature between 225 and 375 °C and time between 1 and 4 h. The resultant CO films have been studied to understand the influence of processing parameters in the thermoelectric, electrical, optical, morphological, and structural properties. Films with a Cu2O single phase are formed when annealing at 225 °C, while CuO single phase films can be obtained at 375 °C. In between, both phases are obtained in proportions that depend on the film thickness and annealing time. The positive sign of the Seebeck coefficient (S), measured at room temperature (RT), confirms the p-type behavior of both oxides, showing values up to 1.2 mV·°C–1 and conductivity up to 2.9 (Ω·m)−1. A simple detector using Cu2O have been fabricated and tested with fast finger touch events.

Dias, D, Lapa N, Bernardo M, Godinho D, Fonseca I, Miranda M, Pinto F, Lemos F.  2017.  Properties of chars from the gasification and pyrolysis of rice waste streams towards their valorisation as adsorbent materials. Waste Management. 65:186-194. AbstractWebsite

Rice straw (RS), rice husk (RH) and polyethylene (PE) were blended and submitted to gasification and pyrolysis processes. The chars obtained were submitted to textural, chemical, and ecotoxic characterisations, towards their possible valorisation. Gasification chars were mainly composed of ashes (73.4–89.8wt%), while pyrolysis chars were mainly composed of carbon (53.0–57.6wt%). Silicon (Si) was the major mineral element in all chars followed by alkaline and alkaline-earth metal species (AAEMs). In the pyrolysis chars, titanium (Ti) was also a major element, as the feedstock blends contained high fractions of PE which was the main source of Ti. Gasification chars showed higher surface areas (26.9–62.9m2g−1) and some microporosity, attributed to porous silica. On the contrary, pyrolysis chars did not present a porous matrix, mainly due to their high volatile matter content. The gasification bed char produced with 100% RH, at 850°C, with O2 as gasification agent, was selected for further characterization. This char presented the higher potential to be valorised as adsorbent material (higher surface area, higher content of metal cations with exchangeable capacity, and lowest concentrations of toxic heavy metals). The char was submitted to an aqueous leaching test to assess the mobility of chemical species and the ecotoxic level for V. fischeri. It was observed that metallic elements were significantly retained in the char, which was attributed mainly to its alkaline character. This alkaline condition promoted some ecotoxicity level on the char eluate that was eliminated after the pH correction.

Cordeiro, T, Castiñeira C, Mendes D, Florence Danède, Sotomayor J, Fonseca IM, Gomes da Silva M, Paiva A, Barreiros S, Cardoso MM, Viciosa MT, Correia NT, Dionisio M.  2017.  Stabilizing Unstable Amorphous Menthol through Inclusion in Mesoporous Silica Hosts. Molecular Pharmaceutics. 14:3164-3177., Number 9 AbstractWebsite
n/a
Hussain, A, Semeano ATS, Palma SICJ, Pina AS, Almeida J, Medrado BF, Pádua ACCS, Carvalho AL, Dionísio M, Li RWC, Gamboa H, Ulijn RV, Gruber J, Roque ACA.  2017.  Tunable Gas Sensing Gels by Cooperative Assembly. Advanced Functional Materials. 27:1700803–n/a., Number 27 AbstractWebsite

The cooperative assembly of biopolymers and small molecules can yield functional materials with precisely tunable properties. Here, the fabrication, characterization, and use of multicomponent hybrid gels as selective gas sensors are reported. The gels are composed of liquid crystal droplets self-assembled in the presence of ionic liquids, which further coassemble with biopolymers to form stable matrices. Each individual component can be varied and acts cooperatively to tune gels' structure and function. The unique molecular environment in hybrid gels is explored for supramolecular recognition of volatile compounds. Gels with distinct compositions are used as optical and electrical gas sensors, yielding a combinatorial response conceptually mimicking olfactory biological systems, and tested to distinguish volatile organic compounds and to quantify ethanol in automotive fuel. The gel response is rapid, reversible, and reproducible. These robust, versatile, modular, pliant electro-optical soft materials possess new possibilities in sensing triggered by chemical and physical stimuli.

Lourenço, SC, Torres CAV, Nunes D, Duarte P, Freitas F, Reis MAM, Fortunato E, Moldão-Martins M, da Costa LB, Alves VD.  2017.  Using a bacterial fucose-rich polysaccharide as encapsulation material of bioactive compounds. International Journal of Biological Macromolecules. 104:1099-1106. AbstractWebsite

The potential of a bacterial exopolysaccharide named FucoPol, produced by the bacterium Enterobacter A47, as encapsulation matrix was explored. Spherical capsules with a smooth surface were produced by spray drying. The obtained microcapsules had average diameters ranging from 0.5 to 26.7μm and presented thin walls (thickness from 222 to 1094nm). The capsules were loaded with two bioactive compounds: gallic acid (GA) and oregano essential oil (OEO). Both bioactive materials were encapsulated in FucoPol particles, retaining their antioxidant activity after the drying process. Release studies showed that GA release in simulated gastric and intestinal fluids was faster than that of OEO, envisaging that the latter had established stronger interactions with the polymer matrix. These results suggest that FucoPol has a good potential for use as encapsulating material of bioactive compounds for application in several areas, including food, cosmetic or pharmaceutical products.

2016
Bianchi, C, Ferreira LM, Loureiro J, Rodrigues A, Duarte P, Baptista AC, Ferreira IM.  2016.  Vanadium Pentoxide Alloyed with Graphite for Thin-Film Thermal Sensors, Mar. Journal of Electronic Materials. 45:1987–1991., Number 3 AbstractWebsite

The thermoelectric (TE) properties of vanadium pentoxide (V2O5) alloyed with graphite (G) were studied as a function of its incorporation percentage. Variable weight percentages of graphite powder (0–50{%}) were added to V2O5 powder and their mixtures were evaporated by a thermal evaporation technique to form thin films with a thickness in the range of 30–80 nm. In the infrared wavelength region, the transmittance of the obtained films increased as the G percentage was increased, while in the visible range, it decreased with G up to 10{%}. The TE properties were improved when G was in the range of 10–30{%}, while it decreased for the other percentages: Seebeck coefficient (S) changed from 0.6 mV/K to 0.9 mV/K and was zero with a G of 50{%}; the electrical conductivity varied slightly from 5 ($Ømega$m)−1 to 0.7 ($Ømega$m)−1 while the mobility improved from 0.07 cm2/V s to 1.5 cm2/V s and the respective carrier concentration was reduced, from 1 × 1018 cm−3 to 4 × 1016 cm−3. These films were applied as temperature sensors evaluating the thermovoltage as a function of thermal gradient between two electrodes, in which one was maintained at room temperature.

Deuermeier, J, Wardenga HF, Morasch J, Siol S, Nandy S, Calmeiro T, Martins R, Klein A, Fortunato E.  2016.  {Highly conductive grain boundaries in copper oxide thin films}, jun. JOURNAL OF APPLIED PHYSICS. 119, Number 23 Abstract
n/a
Dias, L, Simões S.  2016.  ) Integrative Smart City Planning – Energy system modelling for the city of Évora, 30-31 May . ETSAP Workshop . , Cork, Ireland
Gouveia, JP, Simões S, Dias L, Seixas J.  2016.  The InSmart integrated approach towards modelling smart low carbon cities, 25 November . EERA Conference 2016. , UK: University of Birmingham
Basilio, N, Garnier T, Avo J, Danel M, Chassaing S, Pina F.  2016.  Synthesis and multistate characterization of bis-flavylium dications - symmetric resorcinol- and phloroglucinol-type derivatives as stochastic systems, 2016. Rsc Advances. 6(74):69698-69707. AbstractWebsite
n/a
Simões, S, Dias L, Seixas J, Gouveia JP.  2016.  INSMART, 15 November . UERA Workshop on “Sustainable Smart Cities”. , Barcelona, Spain: Smart City Expo
Dias, L, Seixas J, Gouveia JP, Simões S.  2016.  Integrative Smart City Planning – Energy system modelling at city scale, 13-15 July . 22nd Annual International Sustainable Development Research Society Conference . , Lisbon, Portugal
Fortes, P, Dias L, Seixas J.  2016.  The sustainability of future scenarios of the Portuguese power system, 13-15 July . 22nd Annual International Sustainable Development Research Society Conference . , Lisbon, Portugal
Barbosa, JP, Dias L.  2016.  Solar Power Deployment In Brazil – Testing Electric Vehicles As The Wheel To Promote Solar Power, 11-14 October . 11th ISES EuroSun Conference . , Palma Mallorca, Spain
Chávez-Rodríguez, M, Dias L, Simoes S, Seixas J, Szklo A, Lucena FPA, Hawkes A.  2016.  Natural Gas Outlook for the Southern Cone: outcomes from an hourly basis TIMES natural gas & power model, 1-3 June. 35th International Energy Workshop. , Cork, Ireland
De Miglio, R, Chiodi A, Simoes S, Long G, Pollard M, Gouveia JP, Gargiulo M, Giannakidis G.  2016.  New methodological approach for planning cities sustainable and resilient energy futures – the case of the InSMART project, 1-3 June. International Energy Workshop. , Ireland: University College Cork
Martins, M, Baptista PV, Mendo AS, Correia C, Videira P, Rodrigues AS, Muthukumaran J, Santos-Silva T, Silva A, da Silva FGMC, Gigante J, Duarte A, Pombeiro AJL, Fernandes AR.  2016.   In vitro and in vivo biological characterization of the anti-proliferative potential of a cyclic trinuclear organotin(IV) complex. Molecular BioSystems. (12) AbstractWebsite

Identification of novel molecules that can selectively inhibit the growth of tumor cells, avoid causing side effects to patients and/or intrinsic or acquired resistance, usually associated with common chemotherapeutic agents, is of utmost importance. Organometallic compounds have gained importance in oncologic chemotherapy, such as organotin(IV) complexes. In this study, we assessed the anti-tumor activity of the cyclic trinuclear organotin(IV) complex with an aromatic oximehydroxamic acid group [nBu2Sn(L)]3(H2L = N,2-dihydroxy-5-[N-hydroxyethanimidoyl]benzamide) – MG85 – and provided further characterization of its biological targets. We have previously shown the high anti-proliferative activity of this complex against human colorectal and hepatocellular carcinoma cell lines and lower cytotoxicity in neonatal non-tumor fibroblasts. MG85 induces tumor cell apoptosis and down-regulation of proteins related to tubulin dynamics (TCTP and COF1). Further characterization included the: (i) evaluation of interference in the cell cycle progression, including the expression of critical genes; (ii) affinity to DNA and the corresponding mode of binding; (iii) genotoxic potential in cells with deficient DNA repair pathways; and (iv) in vivo tumor reduction efficiency using mouse colorectal carcinoma xenografts.

Cordeiro, T, Santos AFM, Nunes G, Cunha G, Sotomayor JC, Fonseca IM, F. Danède, Dias CJ, Cardoso MM, N. T. Correia, Viciosa MT, Dionísio M.  2016.  Accessing the Physical State and Molecular Mobility of Naproxen Confined to Nanoporous Silica Matrixes. The Journal of Physical Chemistry C . 120(26):14390–14401.Website
Fortunato, Gaspar, Diana, Duarte, Candido, Pereira, Águas, Hugo, Vicente, António, Dourado, Fernando, Gama, F. M., Martins R.  2016.  Chapter 11 - Optoelectronic Devices from Bacterial NanoCellulose. Bacterial Nanocellulose. :19pp..: Elsevier Inc.
Dionísio, M, Braz L, Corvo M, Lourenço JP, Grenha A, da Costa AMR.  2016.  Charged pullulan derivatives for the development of nanocarriers by polyelectrolyte complexation. International journal of biological macromolecules. 86:129-138.: Elsevier AbstractWebsite

Pullulan, a neutral polysaccharide, was chemically modified in order to obtain two charged derivatives: reaction with SO3.DMF complex afforded a sulfate derivative (SP), while reaction with glycidyltrimethylammonium chloride gave a quaternary ammonium salt (AP). The presence of the charged groups was confirmed by FTIR. Assessment of the positions where the reaction took place was based on 1H- and 13C NMR (COSY, HSQC-TOCSY, HSQC-DEPT, and HMBC) experiments. Estimation of the degree of substitution (DS) was made from elemental analysis data, and further confirmed by NMR peak areas in the case of AP. These new derivatives showed the capability to condense with each other, forming nanoparticles with the ability to associate a model protein (BSA) and displaying adequate size for drug delivery applications, therefore making them good candidates for the production of pullulan-based nanocarriers by polyelectrolyte complexation.

Aroso, IM, Silva JC, Mano F, Ferreira ASD, Dionísio M, Sá-Nogueira I, Barreiros S, Reis RL, Paiva A, Duarte ARC.  2016.  Dissolution enhancement of active pharmaceutical ingredients by therapeutic deep eutectic systems. European Journal of Pharmaceutics and Biopharmaceutics. 98:57-66.Website