INETI - Artigos em revistas internacionais
Permanent URI for this collection
Browse
Recent Submissions
- Does a shell matter for defence? Chemical deterrence in two cephalaspidean gastropodes with calcified shellsPublication . Neves, R.; Gaspar, Helena; Calado, GonçaloOpisthobranch molluscs show an evolutionary trend to reduce, internalize and lose the shell. Many of them base their defensive strategies on natural deterrent products and current evolutionary theory suggests that the acquisition of chemical defences preceded shell reduction and loss, which has characterized the evolution of this group. Here we show that basal, shelled opisthobranch molluscs are defended against sympatric predators even if their protective shell is removed. The cephalaspideans Bulla striata and Haminoea orbignyana, both with distinct shell calcification, significantly deterred feeding by sympatric crab and fish predators, both in laboratory and field assays. However, our results argue against a progressive increment of chemical defences associated with shell reduction, because the cephalaspidean with the more fully calcified shell, Bulla striata, was also the more deterrent. These findings suggest that effective chemical defences might have evolved independently from shell loss, at least in basal opisthobranchs such as cephalaspideans.
- Synthesis, spectroscopy, photophysics and thermal behaviour of stilbene-based triarylamines with dehydroabietic acid methyl ester moietiesPublication . Gigante, Bárbara; Esteves, M. Alexandra; Pires, N.; Davies, Matthew L.; Douglas, Peter; Fonseca, Sofia M.; Burrows, Hugh D.; Pina, João; Melo, João Seixas deNovel stilbene-based triarylamines with dehydroabietic acid methyl ester moieties have been synthesised by palladium catalysed C–N coupling reactions. The presence of the bulky dehydroabietic acid group increases solubility, hinders crystallisation and permits their sublimation while preserving their electronic and optical characteristics. This makes them good candidates for various molecular electronic applications. We report a detailed characterisation of their electrochemical, spectroscopic and photophysical properties. In addition, the thermal stability and behaviour is discussed with reference to the potential for preparation of stable thin films.
- Detection of bovine Babesiosis in Mozambique by a novel seminested hot-start PCR method.Publication . Martins, Tiago M.; Pedro, Olívia C.; Rubina, Caldeira; Rosário, Virgílio do; Neves, L.; Domingos, AnaBabesiosis is a tick borne disease (TBD) caused by parasites of the genus Babesia, with considerable worldwide economic, medical, and veterinary impact. Bovine babesiosis and other TBDs were considered responsible for 50% of the deaths of cattle that occurred in Mozambique in the first year after importation from neighbouring countries. Here, we present the detection of Babesia bigemina and Babesia bovis in cattle from Mozambique using two distinct PCR methods. For this study, blood samples were collected in one farm located near Maputo city. The DNA samples were analyzed using a previously described nested PCR and a novel hot-start PCR method. Primers were selected for the hot-start PCR based on the putative gene of an undescribed aspartic protease named babesipsin, present in both B. bovis and B. bigemina. The combination of hot-start polymerase and long primers (29–31 bp) were in this study determinant for the successful amplification and detection in only one PCR. With a seminested approach the sensitivity was further increased. The babesipsin seminested hot-start PCR was in this study more sensitive than the nested PCR. A total of 117 field samples were tested by seminested hot-start PCR, and 104 were positive for B. bigemina (90%), 97 were positive for B. bovis (82%), 86 were mixed infections (52%) and only 2 were negative for both Babesia species (1.7%). The results confirm that this area of Mozambique is endemic for babesiosis, and that this TBD should be regarded as a threat for imported cattle.
- Building a collaboratory in an engineering R&D organizationPublication . Correia, Zita; Egreja, Catarina; Barrulas, Maria Joaquina; Gil, Rui; Ferreira, Diogo R.This paper presents the results achieved throughout the process of preparing the ground to develop a collaboratory in an Engineering R&D organization. This case study is part of a broader research project engaged in building a collaboratory in order to share knowledge and resources among the Portuguese State laboratories. In the process of preparing the ground to develop the collaboratory in the first of the laboratories studied, an information audit was conducted and an online survey was launched. The survey targeted 241 people, including mainly professional researchers, but also research trainees and some technical staff integrating the research teams. The questionnaire was designed so as to collect data on the organization’s information management and information culture, and on the information flows taking place, and their relationship with the objectives of the organization. The questionnaire comprised two distinct and independent parts. The first (on the organization’s information culture and information management) obtained seventy nine responses, while the second (information flows) achieved ninety two, corresponding to 32,8% and 38,2% of the total population, respectively. The work carried out provided the basic requirements for the task of developing a software infrastructure to support the collaboratory, addressing the various aspects of collaborative tools, information archiving, hierarchical tag classification, search, transparent integration of the user local environment with the platform and remote control of scientific instruments.
- Cork agglomerates as an ideal core material in lightweight structuresPublication . Castro, Osvaldo; Silva, José M.; Devezas, Tessaleno; Silva, Arlindo; Gil, LuísThe experiments carried out in this investigation were oriented in order to optimize the properties of cork-based agglomerates as an ideal core material for sandwich components of lightweight structures, such as those used in aerospace applications. Static bending tests were performed in order to characterize the mechanical strength of different types of cork agglomerates which were obtained considering distinct production variables. The ability to withstand dynamic loads was also evaluated from a set of impact tests using carbon-cork sandwich specimens. The results got from experimental tests revealed that cork agglomerates performance essentially depends on the cork granule size, its density and the bonding procedure used for the cohesion of granulates, and these parameters can be adjusted in function of the final application intended for the sandwich component. These results also allow inferring that optimized cork agglomerates have some specific properties that confirm their superior ability as a core material of sandwich components when compared with other conventional materials.
- Validation and quality assurance applied to goat milk chemical composition: minerals and trace elements measurementsPublication . Trancoso, Inês; Roseiro, Luisa B.; Martins, António P. L.; Trancoso, Maria AscensãoIn the present study, quality assurance programmes were implemented to validate and control the analytical methodologies used for the characterization of minerals and trace elements in goat milk from Portuguese breeds. With the exception of chloride that was determined by potentiometric titration, all the other elements were determined by spectroscopic techniques after different sample decomposition: P was measured by ultraviolet-visible molecular absorption spectrometry, Ca, Fe, K, Mg, Mn, Na and Zn by flame atomic absorption spectrometry and Cd, Co, Cr, Cu, Mo, Ni and Pb by electrothermal atomic absorption spectrometry. The methods performance characteristics, namely specificity, limit of detection, limit of quantification, working range, precision and trueness were evaluated. Measurement uncertainty was expressed in terms of precision and trueness. Precision under intralaboratory reproducibility conditions was estimated from triplicate analysis, and the trueness component was estimated in terms of overall recovery using either skim milk powder certified reference materials or spiked samples. The results obtained are discussed on the basis of the performance criteria required by EC regulations to verify when a method is suitable for food control. The methods used for the characterization of minerals and trace elements in goat milk complied with EC requirements since there was no matrix influence, the Horrat values were < 2.0, recoveries were within the interval 1.00 ± 0.10 for minerals and 1.00 ± 0.20 for trace elements and the combined uncertainty of the results were lower than the maximum standard uncertainty calculated using the uncertainty function approach. In relation to the limits of detection and quantification, the limits obtained for Pb were lower than those specified by EC regulation.
- Mass spectrometric analysis of epimeric 3α/3β functionalized steroids.Publication . Ramos, Susana Sofia; Ramalho, Luís; Costa, Mafalda; Teixeira, Adriano; Almeida, Paulo; Costa, Maria do CéuTandem mass spectrometry (MS/MS) using an atmospheric pressure chemical ionization (APCI) source in positive mode (+) reveals different intensity ratios of two fragment peaks of the epimeric cholestane derivatives synthesized from 3{460}- or 3β-cholestanol. The investigation of the fragmentation pattern obtained from their full scan and/or collision induced dissociation (CID) spectra in the case of the cholestane skeleton together with the respective electronic ionization (EI) spectra supports a distinction of the epimers.