Publications

Abstract This work investigates the Portuguese scientific production published in journals indexed in SCOPUS and Web of Science under the topic of Information and Communication Technologies (ICT) in the field of education. The main objective is to characterize the methodological approaches with special emphasis given to qualitative research. The articles have been categorized according to their methodological approaches (i.e., theoretical or empirical studies, including documental and non-documental - experimental, quasi-experimental and non-experimental). The abstracts have also been coded according to their main themes and operative verbs. After collecting all the available information, a database was created in a spreadsheet. One researcher read all the abstracts and decided whether the work was to be included or not in the corpus of analysis. After this, a second researcher reviewed the selection. Whenever an abstract did not present all the required information, the researchers tried to find the complete paper. If they failed to find it the record should be kept nonetheless. After the first researcher coded all the items, the second researcher reviewed the coding. When they disagreed, they discussed carefully the pros and cons and then adopted a solution; if the disagreement persisted they were expected to present their arguments to the senior researcher, who would decide the matter, but it has not been necessary to use this solution. Preliminary results reveal that methods are not always accurately described and that most works consist of non-experimental designs. Thus, more coherent and precise description of methods, especially when using qualitative analysis, is required. Given the perceived predominance of non-experimental approaches when studying ICT in the field of education, further studies must offer a comparative analysis of the results obtained with foreign production. Simultaneously, research must address the relationship between qualitative methods and sociological factors such as authors' sex, institutional affiliation and cooperation, and publishing impact factor. The results will hopefully bring relevant insights to the Portuguese scientific community interested in studying Information and Communication Technologies in the field of education.

Abstract Disinfection of swimming pool water is essential to inactivate pathogenic microorganisms. However chlorine based disinfectants, the most commonly used, are known to lead to the formation of disinfection by-products (DBPs), some of which have been associated with adverse health effects. Precursors of DBPs include the organic matter present in the water used to fill the swimming pool, human body fluids and personal care products (PCPs) used by swimmers and bathers. The increased use, in the last years, of PCPs lead to an increased concern about the fate of PCPs in swimming pool waters and potential health risks of formed DBPs. In this study, the chemical transformations of two salicylates, benzyl salicylate (BzS) and phenyl salicylate (PS), incorporated in several PCPs, in chlorinated water were investigated. High-performance liquid chromatography (HPLC) with UV-diode-array detection (HPLC-UV-DAD) was used to follow the reaction kinetics and HPLC with mass spectrometry (HPLC-MS) was used to tentatively identify the major transformation by-products. Under the experimental conditions used in this work both salicylates reacted with chlorine following pseudo-first order kinetics: rate constant k = (0.0038 +/- 0.0002) min(-1) and half-life t(1/2) = (182 +/- 10) min for BzS and rate constant k = (0.0088 +/- 0.0005) min(-1) and half-life t(1/2) = (79 +/- 4) min for PS (mean +/- standard deviation). The reactions of the two salicylates in chlorinated water led to the formation of DBPs that were tentatively identified as mono- and dichloro- substituted compounds. Most probably they result from an electrophilic substitution of one or two hydrogen atoms in the phenolic ring of both salicylates by one or two chlorine atoms.

Abstract The present study seeks to become a positive contribution to the research and development of e-learning systems by conducting an exploratory evaluation of the opinions of the academic community of the University of Porto about various technical and social dimensions present in the conception and deployment of learning management systems, both in the context of supporting face-to-face education and as technical infrastructure to blended and distance learning programmes. A survey by questionnaire was applied to 504 members of the academic community at the university, and it was found that among the participants there is still great scepticism towards e-learning and technologically mediated education, especially among younger students. Participants also considered that learning management systems presenting a plethora of features are not as desirable as systems focused on providing a pleasant and consistent user experience.

Abstract Educational institutions are not being effective, because they do not give individuals what they need to integrate into postmodern society, nor produce citizens that postmodern society needs. Shortcomings include the scientific literacy and cognitive domain levels attained, with an aggravating waning interest in science among pre-university students. We present an inquiry module, an inquiry dynamic, as an education resource for the study of perturbations of a chemical equilibrium state by pre-university or university students of basic chemistry, to contribute to the relevance and popularity of science, potentiation of science literacy and development of cognition. Here we describe an investigation with pre-university students.

Abstract Technology is getting closer to the classroom. Laptops, tablets, smartphones and mobile phones are devices that go hand in hand with the student's books and exercise books. The ereaders, which are gradually entering the Portuguese market, have some characteristics that may make them a useful tool for teachers and students. In some countries, the digitization of educational material is a reality. This idea reinforce the need of exploitation these technologies among Portuguese students. The purpose of this study was to determine what impact has the use of ereaders and ebooks on learning, more specifically in the interpretation of texts, vocabulary, pronunciation and the reading speed of 23 students in the advanced levels of Cambridge Advance Certificate (CAE) and Cambridge Proficiency Exam (CPE) at International House of Coimbra. To this end, a plan was drafted with four sessions, one for each of the four weeks of the intervention. A survey was also carried out, we observed the sessions and at the end of the intervention, interviews were conducted with six students and the teacher. Was concluded that - at the light of the theoretical framework in which this experiment was based - ereaders and ebooks can be an important factor in motivating students to read and a useful tool for the classroom, due to the similarity with the traditional book, the portability and the large capacity file storage, enabling the effortless transport of several books, dictionaries and other documents. Regarding the technology and according to the testimony of students and teacher, the ereaders still need many improvements, there being some scepticism when compared to tablets with multimedia capabilities for audio, video and web browsing similar to the computers. Paper is still the format that offers greatest comfort to students, especially when it comes to underlining and note-taking. However, in general, they all feel that the ebooks and digital format will eventually play a key role in schools.

Abstract Tryptophan doped carbon dots (Trp-CD) were microwave synthesized. The optimum conditions of synthesizing of the Trp-CD were established by response surface multivariate optimization methodologies and were the following: 2.5 g of glucose and 300 mg of tryptophan diluted in 15 mL of water exposed for 5 min to a microwave radiation of 700 W. Trp-CD have an average size of 20 nm, were fluorescent with a quantum yield of 12.4% and the presence of peroxynitrite anion (ONOO ) provokes quenching of the fluorescence. The evaluated analytical methodology for ONOO detection shows a linear response range from 5 to 25 mu M with a limit of detection of 1.5 mu M and quantification of 4.9 mu M. The capability of the ONOO quantification was evaluated in standard solutions and in fortified serum samples.

Abstract A systematic molecular dynamics study using large simulation boxes has been performed in order to extend the analysis of the mesoscopic segregation behavior observed in ionic liquids of the 1,3-dialkyl-imidazolium bis(trifluoromethylsulfonyl)imide homologous series, [C(n)C(m)im][Ntf(2)] (2 <= n <= 10, 2 <= m <= n). The analyses include the discussion of the structure factors, S(q), in the low-q range (1.6 <= q/nm(-1) <= 20); the confirmation of the periodicity of the polar network of the ionic liquid and its relation to the so-called intermediate peaks; and the characterization of the polar network and the nonpolar regions that are formed along the series using aggregate analyses by means of five different statistical tools. The analyses confirmed that the percolation of the nonpolar regions into a continuous domain occurs when the total number of carbon atoms in the alkyl chains exceeds six but that this is not a sufficient condition for the emergence of a distinct and intense prepeak. The existence of such a peak also requires that the longer alkyl chain contains more than a critical alkyl length (CAL) of five carbon atoms.

Abstract The industrial application of ionic liquids (ILs) requires the knowledge of their physical properties and phase behavior. This work addresses the experimental determination of the vapor-liquid equilibria (VLE) of binary systems composed of water + imidazolium-based ILs. The ILs under consideration are 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium thiocyanate, 1-butyl-3-methylimidazolium tosylate, 1-butyl-3-methylimidazolium trifluoroacetate, 1-butyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium methanesulfonate, and 1-butyl-3-methylimidazolium acetate, which allows the evaluation of the influence of the IL anion through the phase behavior. Isobaric VLE data were measured at 0.05, 0.07, and 0.1 MPa for IL mole fractions ranging between 0 and 0.7. The observed increase in the boiling temperatures of the mixtures is related with the strength of the interaction between the IL anion and water. The Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) was further used to describe the obtained experimental data. The ILs were treated as molecular associating species with two association sites per IL. The model parameters for the pure fluids and the binary interaction parameter k(ij) between water and ILs were determined by a simultaneous fitting to pure-IL densities, water activity coefficients at 298.15 K and VLE data at 0.1 MPa. Pure-IL densities, water activity coefficients, and VLE data were well described by PC-SAFT in broad temperature, pressure, and composition ranges. The PC-SAFT parameters were applied to predict the water activity coefficients at infinite dilution in ILs, and a satisfactory prediction of experimental data was observed.

Abstract So far, no connection between coffee consumption and breast cancer development has been confirmed, although a positive association has been described for specific individuals. The general rule is that coffee consumption has no effect or actually decreases the incidence of breast cancer. Several coffee constituents such as caffeine, lignans, flavonoids, and hydroxycinnamic acids have been investigated in the context of breast cancer. Hydroxycinnamic acids, especially caffeic and ferulic acids, display a potent antioxidant and anti-radical activity in models of breast cancer, acting through different mechanisms. Although caffeic and ferulic acid have well-established properties, some derivatives of both molecules, possessing slight modifications in their structure, have improved chemotherapeutic activity toward breast cancer cells. Therefore, natural phytochemical molecules such as those present in coffee are a promising and pragmatic clinical approach, by presenting low toxicity to normal cells and high activity toward their malignant counterparts.

Abstract Gemini surfactants have been successfully used as components of gene delivery systems. In the present work, a family of gemini surfactants, represented by the general structure [CmH2m+1(CH3)(2)N+(CH2)(s)N (+)(CH3)(2)CmH2m+1]2Br , or simply m-s-m, was used to prepare cationic gene carriers, aiming at their application in transfection studies. An extensive characterization of the gemini surfactant-based complexes, produced with and without the helper lipids cholesterol and DOPE, was carried out in order to correlate their physico-chemical properties with transfection efficiency. The most efficient complexes were those containing helper lipids, which, combining amphiphiles with propensity to form structures with different intrinsic curvatures, displayed a morphologically labile architecture, putatively implicated in the efficient DNA release upon complex interaction with membranes. While complexes lacking helper lipids were translocated directly across the lipid bilayer, complexes containing helper lipids were taken up by cells also by macropinocytosis. This study contributes to shed light on the relationship between important physico-chemical properties of surfactant-based DNA vectors and their efficiency to promote gene transfer, which may represent a step forward to the rational design of gene delivery systems.