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- Sequential injection system for the spectrophotometric determination of ammonium in Portuguese estuarine watersPublication . Segundo, Ricardo L. A.; Mesquita, Raquel B. R.; Ferreira, M. Teresa S. O. B.; Teixeira, Catarina F. C. P.; Bordalo, Adriano A.; Rangel, António O. S. S.
- Development of a sequential injection gas diffusion system for the determination of ammonium in transitional and coastal watersPublication . Segundo, Ricardo Alves; Mesquita, Raquel B. R.; Ferreira, Maria Teresa Soares Oliveira Barbosa; Teixeira, Catarina Fernanda Carvalho Pinheiro; Bordalo, Adriano Agostinho; Rangel, António O. S. S.This work describes the development of a sequential injection system for the ammonium determination in transitional and coastal waters with a wide salinity range. Estuarine waters are rather complex matrices as their characteristics change considerably along the salinity gradient, as well as the ammonium levels. The developed system effectively solves these issues by converting ammonium into ammonia and using a gas diffusion unit (GDU) for matrix removal. The ammonium determination in a wide quantification range (0.1–5.0 mg L−1) was obtained with small changes in the protocol sequence and was applied, not only to estuarine samples, but also well water samples (low salinity) and coastal waters (higher salinity). Spectrophotometry was the chosen detection system to measure the absorbance change in the bromothymol blue acid base indicator caused by the diffusion of ammonia through the GDU. Additionally, the developed system used a green chemistry approach, as there was no indicator reagent consumption per determination, still maintaining a good precision (relative standard deviation lower than 2%) and a low detection limit, 27 μg L−1 (1.5 μM).
- Development of a flow method for the determination of phosphate in estuarine and freshwaters - Comparison of flow cells in spectrophotometric sequential injection analysisPublication . Mesquita, Raquel B. R.; Ferreira, M. Teresa S. O. B.; Tóth, Ildikó V.; Bordalo, Adriano A.; McKelvied, Ian D.; Rangel, António O. S. S.A sequential injection system with dual analytical line was developed and applied in the comparison of two different detection systems viz; a conventional spectrophotometer with a commercial flow cell, and a multi-reflective flow cell coupled with a photometric detector under the same experimental conditions. The study was based on the spectrophotometric determination of phosphate using the molybdenum-blue chemistry. The two alternative flow cells were compared in terms of their response to variation of sample salinity, susceptibility to interferences and to refractive index changes. The developed method was applied to the determination of phosphate in natural waters (estuarine, river, well and ground waters). The achieved detection limit (0.007 mu M PO43-) is consistent with the requirement of the target water samples, and a wide quantification range (0.024-9.5 mu M) was achieved using both detection systems.
- A calorimetric study of egg white proteinsPublication . Ferreira, M.; Hofer, C.; Raemy, A.Egg white is of great interest for many culinary and industrial applications. Egg white is used for coating, gluing, thickening and so on in pasta, desserts, etc. There is thus a great interest from the industrial point of view to better know this raw material, used in very large amounts in the dessert production for example, and to obtain egg white fractions with different functional properties. Various egg white fractions prepared by selected procedures were analyzed by differential scanning calorimetry (DSC). The products resulting from a given fractionation procedure can thus be described by the thermal denaturation parameters (temperatures and enthalpies) of the egg white proteins. This work demonstrates the interest of the DSC technique and proves that the fractionation procedures selected here give the expected protein fractions.
- The importance of the 1st CEB teacher training to know the determinants of academic performance of students with ADHDPublication . Campos, S.; Soares, L.; Ferreira, M.; Chaves, C.; Alves, C.; Martins, C.Introduction: Attention deficit-hyperactivity disorder (ADHD) is an issue that affects a high percentage of school-age population. Thus, working directly with hyperactive students has become an inevitable task in our lives, as educational professionals. Thus, it has become essential to ascertain new and effective teaching practices because understanding a teacher’s role as a facilitating agent in the teaching-learning process is to understand that that role requires specialised preparation. It is in this context that our paper is based. Objective: The aim of this study is to learn whether the continuing training of teachers helps them to acquire better knowledge about ADHD children, improving their perceptions and attitudes. Methodology: from this point of view, the procedure adopted was the descriptive plan by survey. Data were collected using a questionnaire, considered the most appropriated procedure for descriptive studies. This study involved 117 primary teachers from a variety of schools. Most of them only have intial training (the number of teachers with some kind of specialisation in this area is very low). Results: After analysing the survey data, a connection between the results and teacher’s academic qualifications was made and the conclusion drawn is that the quality of the teacher’s practices goes up with the teacher training on this issue. However, initial teacher training may or may not have been developed in the area of hyperactivity. For this reason, some teachers may not be sure of their answers (particularly regarding information pertaining to the main problems related to this issue). Conclusions: The results of the study lead us to conclude that it is extremely important to get appropriate training throughout the professional career. This training can be related directly to this area or to other areas that are directly or indirectly connected to our work with the main aim of improving our intervention in school and to help the children with this pathology.
- A hydroxyapatite–Fe2O3 based material of natural origin as an active sunscreen filterPublication . Piccirillo, C.; Rocha, C.; Tobaldi, D. M.; Pullar, R. C.; Labrincha, J. A.; Ferreira, M. O.; Castro, Paula M. L.; Pintado, M. E.The use of sunscreens as protective barriers against skin damage and cancer, by absorbing harmful UVA and UVB rays, is becoming an increasingly important issue. Such products are usually based on TiO2 or ZnO, although both Fe2O3 and hydroxyapatite (Ca10(PO4)6(OH)2, HAp) doped with metal ions have been reported as being ultraviolet (UV) absorbing materials. HAp is the main component of bone; it is, therefore, highly biocompatible. In the present work, an iron-doped HAp-based material, containing both Fe ions substituted into the HAp structure and iron oxide in hematite (a-Fe2O3) form, was successfully developed from waste cod fish bones. This was achieved through a simple process of treating the bones in a Fe(II) containing solution, followed by heating at 700 C. The material showed good absorption in the whole UV range and did not form radicals when irradiated. The sunscreen cream formulated with this material could be used as a broad sunscreen protector (lcrit > 370 nm), showing high absorption both in the UVA and UVB ranges. Because of its absorption properties it would be classified as 5 star protection according to the Boots UVA star rating system. The cream is also photostable, and does not cause irritation or erythema formation when in contact with the human skin. These results show that a food by-product such as fish bones could be converted into a valuable product, with potential applications in health care and cosmetics. This is the first time a HAp-based sunscreen cream has been developed and validated as a proof of concept.
- Development of a sequential injection system for the determination of nitrite and nitrate in estuarine watersPublication . Mesquita, Raquel B. R.; Ferreira, M. Teresa S. O. B.; Rangel, António O. S. S.
- Chitosan in oral health: a proof of conceptPublication . Costa, E. M.; Silva, Sara; Cardelle-Cobas, A.; Madureira, A. R.; Ferreira, M. O.; Tavaria, Freni K.; Pintado, M. M.Nowadays chitosan has established itself as a high sought material due to its biocompatibility, reduced toxicity and highpercentage of amino groups that confer it specific functionalities, including antimicrobial activity and acceleration of woundhealing, and studies into chitosan’s applicability have shown chitosan’s potential and feasibility. One of the possible fieldsof application for chitosan based products is the oral cavity, since several of the existing oral health products possesssecondary effects. The aim of this work was to prove that chitosan is a feasible component for oral health productsbiofabrication. As such a chitosan based mouthwash was developed and validated through assessment ofin vitroandin vivoantimicrobial activity, antibiofilm activity and sensory properties. The results obtained showed that it was possible tosuccessfully incorporate chitosan in an oral care product while retaining a considerable antimicrobial activity.In vitrotestingdemonstrated that the chitosan mouthwash possessed a wide range of antimicrobial activity against oral pathogens andwas capable of inhibiting microbial adherence and biofilm formation. Direct comparison with two commercial mouthwashesshowed that the chitosan mouthwash possessed stronger activity than both reference samples.In vivotesting showedthat the chitosan mouthwash was very effective in reducing enterococci and streptococci bacterial counts up to 30 min.after rinsing. Overall, the present shows a successful development of a chitosan-based product and is a tangible proof ofconcept for future utilization of chitosan in oral health.
- Monitorização de efluxo de potássio e fosfato de células bacterianas (Listeria Innocua)Publication . Ferreira, M. Teresa S. O. B.; Teixeira, Helena I. S.; Tóth, Ildikó V.; Campos, Francisco M.; Couto, José A.; Hogg, Tim; Rangel, António O. S. S.
- Development of a sequential injection system for the determination of nitrite and nitrate in estuarine watersPublication . Mesquita, Raquel B. R.; Ferreira, M. Teresa S. O. B.; Rangel, António O. S. S.