297 research outputs found
Modulation of tomato pericarp firmness through pH and calcium: Implications for the texture of fresh-cut fruit
The effect of pH and calcium on pericarp firmness and pectin solubility was investigated in tomato fruit (Lycopersicon esculentum Mill. ‘Tavira’). Pericarp disks were vacuum-infiltrated with 50mM CaCI₂ or with distilled water and incubated for 4 h in buffer solutions at pH 4.5 and 7.0, and
subsequently stored at 2 ◦C for 5 days. CaCl2 treatment had a significant effect on firmness retention in disks from turning and ripe fruit. Pericarp disks from mature-green fruit infiltrated with CaCl2 were firmer than untreated tissue after a 4 h incubation period, but the effect of calcium did
not persist during storage at 2 ◦C. pH had a significant effect on the firmness of pericarp disks excised from turning and ripe fruit, but not on mature-green tissue. Treatments at pH 7.0 caused a reduction of the softening rate in disks from turning and ripe fruit, but had no significant effect
at the mature-green stage. Water-soluble pectins decreased significantly in mature-green and ripe pericarp tissue following treatment with CaCl2 at pH 7.0, suggesting that pH affects pectin dissolution. Firmness changes induced by pH and calcium after a 4 h incubation treatment were highly correlated with pectin dissolution. The results indicate that, besides calcium, pH contributes to textural changes in tomato fruit pericarp. Since
wounding inflicted during processing and acidic solutions used to prevent enzymic browning and microbial growth are likely to acidify the apoplast of fresh-cut fruit, the ability to maintain an apoplastic pH near 7.0 can significantly contribute to enhanced firmness of fresh-cut fruit
Combination of vitamin D and dipeptidyl peptidase-4 inhibitors (VIDPP-4i) as an immunomodulation therapy for autoimmune diabetes
Type 1 diabetes (T1D) and latent autoimmune diabetes in adults (LADA) represent the most common types of autoimmune diabetes and are characterized by different age of onset, degrees of immune-mediated destruction of pancreatic beta cells and rates of disease progression towards insulin dependence. Several immunotherapies aimed to counteract autoimmune responses against beta cells and preserve beta-cell function are currently being investigated, particularly in T1D. Preliminary findings suggest a potential role of combination therapy with vitamin D and dipeptidyl peptidase-4 (DPP-4) inhibitors (VIDPP-4i) in preserving beta-cell function in autoimmune diabetes. This manuscript aims to provide a comprehensive overview of the immunomodulatory properties of vitamin D and DPP-4 inhibitors, as well as the rationale for investigation of their combined use as an immunomodulation therapy for autoimmune diabetes
In-between identities and hope in the future: experiences and trajectories of cigano secondary students (SI)
Increasing numbers of Cigano people in Portuguese schools show that this is the most educated generation to date. However, according to recent data only 2.6% are enrolled in secondary education. Using an intersectional approach examining gender, ethnicity, and family socioeconomic status to explore the youngsters’ academic trajectories, and focusing on tensions of the interplay between structural constraints and individual agency, enables us to explore identity reconfiguration processes (‘in- between’). The data, based on 32 semi-structured interviews, point to three main dimensions regarding the youngsters’ aspirations for social mobility: the school relevance to achieve jobs differing from traditional activities; school perceived as a means to develop important transversal skills, useful in broader citizenship contexts; school as a privileged space for inter-ethnic socialisation, with impact on the youngsters’ school and professional future. Participant heterogeneity explains variations in their aspirations for upward mobility, as well as differentiations in the construction processes of in-between identities.This project is funded by the Foundation for Science and Technology, [PTDC/CED-EDG/30175/
2017].info:eu-repo/semantics/publishedVersio
Long-term predation pressure exerted by juvenile flatfish on macrobenthic communities in an estuarine area
Dissertação de mestrado em Ecologia, apresentada ao Departamento de Ciências da Vida da Faculdade de Ciências e Tecnologia da Universidade de CoimbraA pressão de predação exercida por dois abundantes pleuronectiformes, o
linguado (Solea solea) e a solha (Platichthys flesus), foi analisada no estuário do
Mondego, Portugal, durante 10 anos (2003-2013). A amostragem foi realizada com
colheitas mensais e bimensais, usando arrastos de vara em 5 estações. A pressão
de predação anual em comunidades macrobênticas, foi estimada para os três
grupos de idade grupo 0, I e II de cada espécie, determinando os Requisitos para
Manutenção Diária (DMR) e os Requisitos para Crescimento Diário (DGR), que
somados consistem no Consumo Diário de Alimento (DFI). As abundancias
revelaram uma elevada variabilidade interanual na solha, e em menor escala no
linguado, que tem vindo a aumentar desde 2004. No geral, o linguado mostrou uma
maior abundancia e pressão de predação anual, principalmente nos grupos 0 e I,
enquanto que a solha não mostrou nenhum padrão particular. Esta variabilidade
pode estar relacionado com fatores específicos intrínsecos e tolerâncias a factores
ambientais, que são conhecidos por regular a variabilidade de recrutamento. A
pressão de predação anual exercida por ambas as espécies aumentaram de 0.175 g
AFDM m-2 (2004) para o valor máximo de 0.654 g AFDM m-2 (2009), diminuindo
depois para to 0.174 g AFDM m-2 em 2011 e depois aumentando no ano seguinte
para 0.254 g AFDM m-2, mantendo-se estável até 2013. Baseado em análises da
dieta, anfípodes, poliquetas, decápodes e crustáceos foram as presas mais
consumidas, refletindo a variabilidade na pressão de predação da solha e linguado.
Considerando a baixa ordem de magnitude de presas consumidas, o controlo “top
down” dos pleuronetiformes no macrobentos parece não ser relevante,
particularmente quando comparado com outras áreas de viveiro destas espécies.The predation pressure exerted by two abundant flatfishes, sole (Solea
solea) and flounder (Platichthys flesus), was evaluated in the Mondego estuary,
Portugal, over a period of 10 years (2003-2013). Sampling was performed with
monthly and bimonthly surveys using beam trawls, in five selected stations.
Annual predation pressure on macrobenthic communities by each species was
estimated for three age classes: 0, I and II-group, by determining the Daily
Maintenance Requirements (DMR) and the Daily Growth Requirements (DGR),
which added consist of the Daily Food Intake (DFI). Abundances showed a high
inter-annual variability in flounder, and to a lesser extent in sole, which has been
increasing in numbers since 2004. Overall, sole showed a higher abundance and
annual pressure, mainly in 0 and I-group, while flounder did not show any
particular pattern. Such variability may be related with species-specific intrinsic
factors and tolerance to environmental factors, which are known to regulate
recruitment variability. The total annual predation pressure carried out by both
species increased from 0.175 g AFDM m-2 (2004), to a maximum value of 0.654 g
AFDM m-2 (2009), decreasing afterwards to 0.174 g AFDM m-2 in 2011 and then
increase in the next year to 0.254 g AFDM m-2, maintaining stable until 2013. Based
on diet analysis, amphipods, polychaetes, decapods and crustaceans were the most
consumed preys, reflecting the variability in predation pressure by flounder and
sole. Considering the low order of magnitude of consumed prey, top-down control
of flatfish on macrobenthos seemed to be negligible, particularly when compared
to other nursery areas for these species
Edifícios sustentáveis em construção metálica
Dissertação de mestrado integrado em Engenharia CivilA indústria da construção tem um impacte indiscutível na sociedade e no meio ambiente. Para
além de desempenhar funções de proteção e abrigo, promove conforto e bem-estar e, ao mesmo
tempo, contribui ativamente para a economia mundial, sendo ainda responsável por grande parte
dos impactes sobre o meio ambiente. Desta forma, é essencial integrar o conceito e requisitos do
desenvolvimento sustentável neste sector. A forma mais efetiva de o fazer é aplica-lo desde as
fases iniciais de projeto, seja para um novo edifício, seja para a reabilitação de um edifício antigo.
As diversas vantagens de uma construção metálica, como, por exemplo, reciclabilidade, segurança
e produção off-site, proporcionam que este tipo de construção se insira num futuro de “construção
verde”, ou seja, que contribua para a sustentabilidade na construção. Assim, a presente dissertação
tem como objetivo fundamental a identificação de quais os requisitos necessários para garantir a
sustentabilidade ao longo do ciclo de vida de um edifício em estrutura metálica, nas fases de
concepção e pré-projeto. Neste sentido, foi elaborado e distribuído um inquérito com o intuito de
analisar a consideração dos requisitos de sustentabilidade, através de indicadores chave
(indicadores económicos, sociais e ambientais) para projetistas. A metodologia seguida para o
desenvolvimento e aplicação dos inquéritos foi semelhante à apresentada por Ugwu et al (2007) e
Alwear e Clements-Croome (2010). Através da análise das respostas obtidas, verificou-se
unanimidade no que diz respeito à necessidade de incluir, nas fases iniciais de projeto, as
seguintes categorias de indicadores: “conforto térmico”, “fontes renováveis”, “acessibilidade” e
“reutilização/reciclagem”. A combinação de todos os indicadores de sustentabilidade proporciona
o conforto necessário de um determinado edifício para os respetivos habitantes. Os indicadores
analisados devem ser alvo de inserção na fase de projeto para que, deste modo, seja possível
determinar exaustivamente as condições de utilização da moradia, edifício ou loteamento. Ao
abordar todos estes temas na execução do projeto, poder-se-á contribuir para uma construção
económica, usando materiais reciclados e energias renováveis, por exemplo, preparando assim a
habitação para o futuro e, acima de tudo, assegurando o seu conforto.Construction and real estate industries have an undeniable impact on society and the
environment. Apart from projection and shelter functions, buildings promote comfort and
well-being, while actively contributing to the global economy and being responsible for a
great share of the environmental impacts. Thus, it is essential to integrate the concept and
requirements of sustainable development in these sectors. The most effective way to do this is
to apply it right from the early design stages, both for new buildings and rehabilitation.
However, none of them is sufficiently effective in supporting the improvement of buildings’
life cycle sustainability, during early design phases. The various advantages of steel
construction, such as recyclability, safety and off-site production, promote its great role in
fostering sustainable built environment. Thus, this dissertation aims to identify which
fundamental requirements to guarantee sustainability throughout the life cycle of a steel
building structure are, at early design phases. In this sense, an enquire was developed and
distributed to analyse how sustainability requirements are dealt with during design phases,
through key indicators (economic indicators, social and environmental) for designers. The
methodology used for this survey was similar to the one presented by Ugwu et al (2007) and
Clements-Croome and Alwear (2010). Through the analysis of the answers provided, there
was unanimity regarding the need to include in the initial phases of a project, the following
categories of indicators: "thermal comfort", "renewable sources", "accessibility" and
"reuse/recycling”. The combination of all sustainability indicators provides the comfort
needed for a given building. The addressed indicators should be included in the design phase,
in order to be possible to exhaustively determine the use conditions of a building. Addressing
all these issues in early design will contribute to an economic construction, by, for instance,
using recycled materials and renewable energy. In this way, buildings will be prepared for the
future and, above all will be comfortable and healthy places to be in
Impact of aqueous extract of arbutus unedo fruits on limpets (Patella spp.) pâté during storage: proximate composition, physicochemical quality, oxidative stability, and microbial development
Limpets are molluscs widely used in food diet and much appreciated in many regions. The consumption of fishery products rich in polyunsaturated fatty acids has been increasing through filleted products and restructured products. Since food oxidation is the major cause of nutritional quality deterioration in fish products, the interest in the replacement of synthetic antioxidants with natural sources, namely in the preparation of restructured animal products such as burgers, sausages and pâtés, has been increasing. Phenolic compounds from fruits and vegetables have recognised antioxidant properties and are therefore currently considered as good alternatives to synthetic
antioxidants in the food industry. In this study, the effects of the extracts of Arbutus unedo fruits, at two concentration levels (3% and 6%), on proximate composition, hysicochemical properties, oxidative stability and safety of limpets pâté, during 90 days at refrigerated storage, were investigated. After processing, the addition of 3% and 6% of A. unedo extracts into limpets pâté contributed to an increase of 18% and 36% in the total phenolic content and 5% and 36% in the antioxidant capacity, respectively. During storage, the enriched limpets pâté with A. unedo fruit extracts at 6% was more
efficient as an enhancer of oxidative stability, with 34% inhibition of lipid oxidation, highlighting the potential use of A. unedo fruits as a functional ingredient in the fish industry. Overall, the limpets pâté with 6% of A. unedo fruit extracts proved to be more efficient regarding microbial control, and had the lowest changes in the quality parameters such as in colour, texture and pH during 90 days at refrigerated storage.info:eu-repo/semantics/publishedVersio
The interactive effects of microcystin-LR and cylindrospermopsin on the growth rate of the freshwater algae Chlorella vulgaris
Microcystin-LR (MC-LR) and cylindrospermopsin (CYN) are the most representative cyanobacterial cyanotoxins. They have been simultaneously detected in aquatic systems, but their combined ecotoxicological effects to aquatic organisms, especially microalgae, is unknown. In this study, we examined the effects of these cyanotoxins individually and as a binary mixture on the growth rate of the freshwater algae Chlorella vulgaris. Using the MIXTOX tool, the reference model concentration addition (CA) was selected to evaluate the combined effects of MC-LR and CYN on the growth of the freshwater green algae due to its conservative prediction of mixture effect for putative similar or dissimilar acting chemicals. Deviations from the CA model such as synergism/antagonism, dose-ratio and dose-level dependency were also assessed. In single exposures, our results demonstrated that MC-LR and CYN had different impacts on the growth rates of C. vulgaris at the highest tested concentrations, being CYN the most toxic. In the mixture exposure trial, MC-LR and CYN showed a synergistic deviation from the conceptual model CA as the best descriptive model. MC-LR individually was not toxic even at high concentrations (37 mg L(-1)); however, the presence of MC-LR at much lower concentrations (0.4-16.7 mg L(-1)) increased the CYN toxicity. From these results, the combined exposure of MC-LR and CYN should be considered for risk assessment of mixtures as the toxicity may be underestimated when looking only at the single cyanotoxins and not their combination. This study also represents an important step to understand the interactions among MC-LR and CYN detected previously in aquatic systems.info:eu-repo/semantics/publishedVersio
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