Browsing by Issue Date, starting with "2015-05"
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- Cation transporters/channels in plants: Tools for nutrient biofortificationPublication . Pinto, Edgar; Ferreira, Isabel M.P.L.V.O.Cation transporters/channels are key players in a wide range of physiological functions in plants, including cell signaling, osmoregulation, plant nutrition and metal tolerance. The recent identification of genes encoding some of these transport systems has allowed new studies toward further understanding of their integrated roles in plant. This review summarizes recent discoveries regarding the function and regulation of the multiple systems involved in cation transport in plant cells. The role of membrane transport in the uptake, distribution and accumulation of cations in plant tissues, cell types and subcellular compartments is described. We also discuss how the knowledge of inter- and intra-species variation in cation uptake, transport and accumulation as well as the molecular mechanisms responsible for these processes can be used to increase nutrient phytoavailability and nutrients accumulation in the edible tissues of plants. The main trends for future research in the field of biofortification are proposed.
- Da Luz à Imagiologia MédicaPublication . Costa, PedroÂmbito: Palestra a convite do Departamento de Física da Universidade de Trás-os-Montes e Alto Douro (ECT - UTAD) Contexto: VII Fórum Física e Sociedade
- “Green Electrodes” Modified with Au Nanoparticles Synthesized in Glycerol, as Electrochemical Nitrite SensorPublication . Gobelli, Dino; Correa, N. Mariano; Barroso, M. Fátima; Moyano, Fernando; Molina, Patricia G.A new environmentally friendly Au nanoparticles (Au NPs) synthesis in glycerol by using ultraviolet irradiation and without extra-added stabilizers is described. The synthesis proposed in this work may impact on the non-polluting production of noble nanoparticles with simple chemicals normally found in standard laboratories. These Au NPs were used to modify a carbon paste electrode (CPE) without having to separate them from the reaction medium. This green electrode was used as an electrochemical sensor for the nitrite detection in water. At the optimum conditions the green sensor presented a linear response in the 2.0×10−7–1.5×10−5 M concentration range, a good detection sensitivity (0.268 A L mol−1), and a low detection limit of 2.0×10−7 M of nitrite. The proposed modified green CPE was used to determine nitrite in tap water samples.
- Exposure to polycyclic aromatic hydrocarbons and assessment of potential risks in preschool childrenPublication . Oliveira, Marta; Slezakova, Klara; Delerue-Matos, Cristina; Pereira, Maria do Carmo; Morais, SimoneAs children represent one of the most vulnerable groups in society, more information concerning their exposure to health hazardous air pollutants in school environments is necessary. Polycyclic aromatic hydrocarbons (PAHs) have been identified as priority air pollutants due to their mutagenic and carcinogenic properties that strongly affect human health. Thus, this work aims to characterize levels of 18 selected PAHs in preschool environment, and to estimate exposure and assess the respective risks for 3–5-year-old children (in comparison with adults). Gaseous PAHs (mean of 44.5 ± 12.3 ng m−3) accounted for 87 % of the total concentration (ΣPAHs) with 3–ringed compounds being the most abundant (66 % of gaseous ΣPAHs). PAHs with 5 rings were the most abundant ones in the particulate phase (PM; mean of 6.89 ± 2.85 ng m−3) being predominantly found in PM1 (78 % particulate ΣPAHs). Overall child exposures to PAHs were not significantly different between older children (4–5 years old) and younger ones (3 years old). Total carcinogenic risks due to particulate-bound PAHs indoors were higher than outdoor ones. The estimated cancer risks of both preschool children and the staff were lower than the United States Environmental Protection Agency (USEPA) threshold of 10−6 but slightly higher than WHO-based guideline.
- Monomeric and oligomeric flavan-3-ols and antioxidant activity of leaves from different Laurus sp.Publication . Vinha, Ana F.; Guido, Luís F.; Costa, Anabela S. G.; Alves, Rita C.; Oliveira, M. Beatriz P. P.The phenolic profile and antioxidant activity of three endemic Laurus sp. from Portugal were analysed. Dried leaves of L. nobilis L., L. azorica (Seub.) Franco, and L. novocanariensis Rivas Mart., Lousã, Fern. Prieto, E. Días, J. C. Costa & C. Aguiar, collected in the mainland and in the Azores and Madeira archipelagos, respectively, were used to prepare different extracts (aqueous, ethanolic and hydroalcoholic). They were studied regarding their DPPH˙ scavenging activity, total phenolic and flavonoid contents, and the main phenolic compounds were identified by HPLC-DAD-ESI-MS/MS. Total flavonoid contents were 30.1, 46.3, and 36.7 mg of epicatechin equivalents per g of sample (dry weight) for L. nobilis, L. azorica and L. novocanariensis, respectively. Epicatechin was the major compound, representing ∼12.1% of total flavan-3-ols in L. nobilis, ∼25.6% in L. azorica, and ∼19.9% in L. novocanariensis. Although all samples presented a similar phenolic profile, significant differences were observed in their total contents and antioxidant activity.
- O meu guia para a habitaçãoPublication . Castro, Abigail; Campos, Filipa; Marques, António da Silva; Queirós, C. L.Este manual destina-se a indivíduos com problemas de Saúde Mental, tendo como objetivo promover o desenvolvimento de competências necessárias à aquisição e manutenção de uma habitação, no sentido de favorecer a inclusão dos mesmos na comunidade.
- E-assessment in mathematics courses with multiple-choice questions testsPublication . Azevedo, Jose ManuelWith the implementation of the Bologna Process several challenges have been posed to higher education institution, particularly in Portugal. One of the main implications is related to the change of the paradigm of a teacher centered education, to a paradigm that is student centered. This change implies the change of the way to assess courses in higher education institutions. Continuous and formative assessments emerged as the focus, catalyzed by electronic assessment, or e-assessment. This paper presents a case of the implementation of an e-assessment strategy, implemented in order to allow continuous, formative assessment in numerous mathematics classes using multiple-choice questions tests implement in Moodle open-source learning management system. The implementation can be considered a success.
- Cyclotron produced 45Ti-Titanium: why & how… so WHY NOT?Publication . Costa, Pedro; Metello, Luís F.; Cunha, Lídia; Johnson, Richard R.; Mattei, Lidia; Gelbart, W.; Obermair, J.; Dietl, B.; Nauschnig, R.; Artner, Christoph; Lass, Piotr; Currie, Geoff; Carmo, Sérgio; Alves, Francisco; Naia, M. DuarteThere are many different radioisotopes well known and characterized for medical use, with almost all of them able to be artificially produced. Nevertheless, routine clinical applications of PET imaging are still based on 18F, in excess of 97% of the cases, with 11C, 13N and 68Ga sharing the few remaining situations. This trend could change in the – hopingly near – future, since several groups worldwide are busy developing very promising new processes using less conventional radionuclides, aiming to contribute for spreading the use and efficacy of clinical diagnostic using Nuclear Medicine imaging techniques, evolving more and more in the direction of personalized medicine, an worldwide growing societal request. Our group is busy studying 45Ti, interested by its many interesting properties and assuming it as a high-potential candidate: in fact 45Ti presents a physical half-life of 3.09h (50% higher than 18F) together with relevant chemical properties, that enable radiolabelling with bifunctional chelates, ligands or even to radiolabel titanium (di)oxide nanoparticles. Considering that data characterizing excitation functions are mandatory for radionuclide optimal production, the present work refers to our results regarding the 45Sc(p,n)45Ti nuclear reaction, being studied as a potential route to efficiently produce 45Ti in low energy cyclotrons.
- Global and Partitioned Multiprocessor Fixed Priority Scheduling with Deferred Pre-emptionPublication . Davis, Robert I.; Burns, Alan; Marinho, José; Nelis, Vincent; Petters, Stefan M.; Bertogna, MarkoThis article introduces schedulability analysis for global fixed priority scheduling with deferred preemption (gFPDS) for homogeneous multiprocessor systems. gFPDS is a superset of global fixed priority pre-emptive scheduling (gFPPS) and global fixed priority non-pre-emptive scheduling (gFPNS). We show how schedulability can be improved using gFPDS via appropriate choice of priority assignment and final non-pre-emptive region lengths, and provide algorithms which optimize schedulability in this way. Via an experimental evaluation we compare the performance of multiprocessor scheduling using global approaches: gFPDS, gFPPS, and gFPNS, and also partitioned approaches employing FPDS, FPPS, and FPNS on each processor.
- CANDi: context-aware node discovery for short-range cooperationPublication . Alam, Muhammad; Albano, Michele; Radwan, Ayman; Rodriguez, JonathanMulti-standard mobile devices are allowing users to enjoy higher data rates with ubiquitous connectivity. However, the benefits gained from multiple interfaces come at an expense—that being higher energy consumption in an era where mobile devices need to be energy compliant. One promising solution is the usage of short-range cooperative communication as an overlay for infrastructure-based networks taking advantage of its context information. However, the node discovery mechanism, which is pivotal to the bearer establishment process, still represents a major burden in terms of the total energy budget. In this paper, we propose a technology agnostic approach towards enhancing the MAC energy ratings by presenting a context-aware node discovery (CANDi) algorithm, which provides a priori knowledge towards the node discovery mechanism by allowing it to search nodes in the near vicinity at the ‘right time and at the right place’. We describe the different beacons required for establishing the cooperation, as well as the context information required, including battery level, modes, location and so on. CANDi uses the long-range network (WiMAX and WiFi) to distribute the context information about cooperative clusters (Ultra-wideband-based) in the vicinity. The searching nodes can use this context in locating the cooperative clusters/nodes, which facilitates the establishing of short-range connections. Analytical and simulation results are obtained, and the energy saving gains are further demonstrated in the laboratory using a customised testbed. CANDi saves up to 50% energy during the node discovery process, while the demonstrative testbed shows up to 75% savings in the total energy budget, thus validating the algorithm, as well as providing viable evidence to support the usage of short-range cooperative communications for energy savings.
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