289 research outputs found
Essential oils of two portuguese endemic species of lavandula as a source of antifungal and antibacterial agents
Chemical investigations of L. stoechas subsp. luisieri and L. pedunculata essential oils were
analyzed by GC-MS, and the antimicrobial activity was performed against bacteria and fungi isolated
from food sources. The cytotoxicity of the essential oil was performed in NHDF cells using the
MTT method. According to the results, the main compounds of L. stoechas subsp. luisieri essential
oil were trans-α-necrodyl acetate (40.2%), lavandulyl acetate (11%), and trans-α-necrodol (10.4%),
while fenchone (50.5%) and camphor (30.0%) in L. pedunculata essential oil. The antifungal activity
of essential oils was confirmed with MIC values ranging from 1.2 to 18.7 µL/mL; for bacteria, it
ranged from 4.7 to 149.3 µL/mL. Both the Lavandula species tested showed low or equal MIC and
MBC/MFC values for L. stoechas subsp. luisieri essential oil, revealing greater efficacy in antimicrobial
activity. The L. stoechas subsp. luisieri essential oil revealed cytotoxic effects (30 ± 2% of cell viability)
in NHDF cells at all concentrations tested.info:eu-repo/semantics/publishedVersio
Adsorption of fluorobenzene onto granular activated carbon: Isotherm and bioavailability studies
The adsorption of a recalcitran fluoroaromatic compound, fluorobenzene (FB), onto granular activated carbon (GAC) was evaluated. The respective isotherm was obtained and the Langmuir, Freundlich and Redlich–Peterson models were fitted to the experimental data, with the Redlich–Peterson model giving the best fitting. Freundlich model also provided a good fit but the Langmuir model could not adequately fit the experimental data, especially at high FB concentrations. Maximal adsorption capacity of FB onto GAC was foundto be 388 mg of FB per gram of GAC. The reversibility of the adsorption of FB onto GAC was investigated, both in the absence and presence of microorganisms. Abiotic desorption of FB occurred to a small extent (between 3% and 22%, for amounts of FB initially adsorbed to the GAC between 37 and 388 mg g 1), and bioregeneration of GAC was shown to occur when the matrix was exposed to a FB degrading culture, with 58–80% of the adsorbed FB being biodegraded. A residual amount of FB showed not to be bioavailable,
suggesting that part of the adsorbed FB may be irreversibly bound. The fraction of the non-bioavailable FB increased at higher amounts of adsorbed FB, from 19% to 33%. The results indicate that the GAC employed in this study has a good capacity to adsorb FB and that bioregeneration of this matrix is a feasible process
Application of GIS in potential beekeeping assessment: Case study of Montesinho Natural Park (Portugal)
Planners require solutions that address routine work needs and seems essential to improving efficiency and
productivity. There are a great number of different factors related to beekeeper activity as well the quality and
productivity of different bee products. The spatial analysis is a powerful tool for overlap and relates various levels
of information on a map, and consequently a very useful for beekeeping activity planning. This work proposes
and applies a methodology to potential beekeeping assessment in Montesinho Natural Park, a region in the
northwest of Portugal. The beekeeping potential maps were developed with the following data sources: legal
standards, vegetation, land use, topography, water resources, roads, electromagnetic fields, and some honey
physico-chemical analysis. The design and implementation of spatial analysis model based on Geographic
Information System (GIS) to beekeeping planning activities has already been described by Anjos et al (2014).
Spatial analysis techniques allows to define the potential beekeeper map supporting the beekeeper management
in this region. Anjos O, Silva G, Roque N, Fernandez P, 2014. GIS based analysis to support the beekeeping
planning. Book of abstracts of the International Symposium on Bee Products 3rd edition – Annual meeting of the
International Honey Commission (IHC), Faculty of medicine, University of Rijeka, p:6
Why, when, and how fast innovations are adopted
When the full stock of a new product is quickly sold in a few days or weeks,
one has the impression that new technologies develop and conquer the market in
a very easy way. This may be true for some new technologies, for example the
cell phone, but not for others, like the blue-ray. Novelty, usefulness,
advertising, price, and fashion are the driving forces behind the adoption of a
new product. But, what are the key factors that lead to adopt a new technology?
In this paper we propose and investigate a simple model for the adoption of an
innovation which depends mainly on three elements: the appeal of the novelty,
the inertia or resistance to adopt it, and the interaction with other agents.
Social interactions are taken into account in two ways: by imitation and by
differentiation, i.e., some agents will be inclined to adopt an innovation if
many people do the same, but other will act in the opposite direction, trying
to differentiate from the "herd". We determine the conditions for a successful
implantation of the new technology, by considering the strength of advertising
and the effect of social interactions. We find a balance between the
advertising and the number of anti-herding agents that may block the adoption
of a new product. We also compare the effect of social interactions, when
agents take into account the behavior of the whole society or just a part of
it. In a nutshell, the present model reproduces qualitatively the available
data on adoption of innovation.Comment: 11 pages, 13 figures (with subfigures), full paper (EPJB 2012) on
innovation adoption mode
The dynamics of opinion in hierarchical organizations
We study the mutual influence of authority and persuasion in the flow of
opinion. Many social organizations are characterized by a hierarchical
structure where the propagation of opinion is asymmetric. In the normal flow of
opinion formation a high-rank agent uses its authority (or its persuasion when
necessary) to impose its opinion on others. However, agents with no authority
may only use the force of its persuasion to propagate their opinions. In this
contribution we describe a simple model with no social mobility, where each
agent belongs to a class in the hierarchy and has also a persuasion capability.
The model is studied numerically for a three levels case, and analytically
within a mean field approximation, with a very good agreement between the two
approaches. The stratum where the dominant opinion arises from is strongly
dependent on the percentage of agents in each hierarchy level, and we obtain a
phase diagram identifying the relative frequency of prevailing opinions. We
also find that the time evolution of the conflicting opinions polarizes after a
short transient.Comment: 6 pages, 5 figures, submitted to Phys. Rev.
Valor nutricional e sensorial de um pão à base de farinha de batata-doce
O pão é um alimento que está presente na dieta da população portuguesa visto ser
um bem acessÃvel, quer em termos de preço quer de disponibilidade no mercado.
No entanto, a sua composição nutricional caracteriza-se por elevados valores de
hidratos de carbono e deficiências em proteÃna e minerais. A grande oferta de
produtos alimentares hipercalóricos associada a uma vida sedentária da população
conduziu à obesidade verificada na população em geral, de que Portugal não é
exceção, que está associada a complicações metabólicas nomeadamente a diabetes.
Uma das estratégias de combate a esta epidemia passa pela redução da
disponibilidade destes alimentos e promoção de escolha de alimentos mais
saudáveis. Atendendo à necessidade de inverter esta tendência, neste projeto foram
desenvolvidas várias formulações com um ingrediente pouco comum na
panificação nacional: a batata doce. Escolheu-se este ingrediente por ser fonte de
fibra e de hidratos de carbono complexos que prolongam a saciedade, regulam a
gordura em circulação, normalizam os picos de glicemia e é considerado uma boa
fonte de minerais. Em termos organoléticos pode também adicionar um sabor doce
natural, cor e aroma ao pão.
No total de 9 formulações produzidas foram selecionados os pães com um maior
nÃvel de aceitação e com uma composição nutricional mais apelativa comparando
com a formulação controlo produzida apenas com farinha de trigo. Destas,
destacaram-se o pão com farinha de batata-doce tradicional, o pão com farinha de
batata doce com farelo de aveia, o pão com farinha de batata-doce da variedade
laranja com farelo de aveia e, por último, o pão com batata-doce tradicional cozida.
Outros ingredientes utilizados nestas formulações que contribuÃram para o seu
valor nutricional, foram as sementes de girassol e de sésamo. Estas formulações
apresentam quantidades de energia, hidratos de carbono e de sal mais reduzidas e
também quantidades de fibra comparativamente superiores ao controlo.
Relativamente aos minerais, possuem quantidades significativas de cálcio, potássio
e fósforo, destacando a formulação de batata doce com farelo de aveia que
apresenta valores de aproximadamente o dobro das quantidades presentes no pão
controlo, o que revela ser uma boa fonte alimentar destes minerais. Com estas
caraterÃsticas, estes pães enriquecidos com batata-doce podem ser um potencial de
utilização em indivÃduos obesos e/ou diabéticos em alternativa ao pão branco
tradicional.info:eu-repo/semantics/publishedVersio
Biodegradation of water emerging pharmaceutical contaminants by two microbial consortia from different origins
Development of dairy beverages functionalized with pure ergosterol and mycosterol extracts: an alternative to phytosterol-based beverages
In the present work, Agaricus bisporus extracts obtained by ultrasound-assisted extraction (UAE), and ergosterol, were incorporated into dairy beverages at concentrations mimicking commercial phytosterol-added yogurts, to work as alternatives. The samples were analysed for nutritional and bioactive properties, and compared with controls (yogurts with no additives or phytosterols), at two storage times (right after incorporation (ST = 0) and after seven days at 4 °C (ST = 7)). The ones incorporated with the extract (YAb) and with ergosterol at the same concentration as in the extract (YPEAb) showed similar antioxidant properties as the ones with phytosterols (YPhy), but a higher cytotoxicity against tumor cells. YPEPhy, the sample with ergosterol at the same amount as phytosterols in YPhy, was the strongest in both bioactivities. For YAb, YPEAb and YPEPhy the antioxidant capacity increased from ST = 0 to ST = 7, meaning that the extract and ergosterol protected the yogurt from oxidation, improving the shelf life. Nutritional parameters were identical for all samples.The authors acknowledge FCT (Portugal) for financial support to (UID/AGR/00690/2013), Sandrina A. Heleno (SFRH/BPD/101413/2014), L. Barros (SFRH/BPD/107855/2015) and R.C. Calhelha (SFRH/BPD/BPD/68344/2010); POCI-01-0145-FEDER-006984 (LA LSRE-LCM), funded by FEDER, through POCI-COMPETE2020 and FCT; Project NORTE-01-0145-FEDER-000006.info:eu-repo/semantics/publishedVersio
Development of innovative hybrid sandwich panel slabs: Experimental results
The authors appreciate the collaboration of the following labs: Civitest for developing DHCC materials, PIEP for conducting VARTM process (Eng. Luis Oliveira) and Department of Civil Engineering of Minho University to perform the tests (Mr. Antonio Matos and Eng. Marco Jorge).In this paper, a new generation of composite sandwich slab is proposed as a solution for the rehabilitation
of slabs in old masonry buildings. An innovative solution was developed during this research formed by
four components: a Deflection Hardening Cement Composite (DHCC) layer on the top compression skin, a
glass fiber reinforced polymer (GFRP) skin at the bottom tension surface, GFRP ribs to transfer shear from
top to bottom layers, and foam core for thermal-insolation purposes. The DHCC layer contributes significantly
for the load carrying and deflection capacity due to its stiffness, compressive strength and toughness,
offers resistance to the occurrence of buckling phenomena in the GFRP ribs, improves the
performance of this structural concept against impact and fire, and constitutes an excellent medium
for the application of finishing materials, like ceramics or timber. Two different hybrid composite slabs
were developed and tested, and their behavior was assessed under flexural loading. The results showed
that the developed hybrid sandwich slabs accomplish all design requisites for serviceability and ultimate
limit states, and assure a stiffness/dead-weight and load-capacity/dead-weight ratios much higher than
conventional structural slab systems.FCT - Fundação para a Ciência e Tecnologi
Heat and pH stable curcumin-based hydrophylic colorants obtained by the solid dispersion technology assisted by spray-drying
Natural food colorants are on demand due to food safety concerns related with some synthetic counterparts.
Health-friendly alternatives can be available from plant sources, which include curcumin extracted
from Curcuma longa L. However, its industrial use is difficult to achieve due to the low water affinity, pH
and thermal instability, which is particularly challenging, e.g. for baked foods. In this work, the solid dispersion
technique followed by spray-drying, an emergent approach in the context of colorants, was
applied to curcumin using k-carrageenan, poly(vinyl alcohol) and polyvinylpyrrolidone, as the encapsulant
materials. An orthogonal central composite design with dummy-variables was applied, and principal
component analysis (PCA) and hierarchical cluster analysis (HCA) carried out to identify the experimental
conditions leading to the most effective formulations. In general, particles with a wide range of pH and
heat stability have been produced depending on the chosen encapsulant material, used formulation (curcumin,
surfactant and polymer contents), and synthesis conditions (pH). Moreover, the used mathematical
approach showed to be a valuable tool to support the development of tailor-made formulations
directed to specific applications where pH and temperature are relevant processing parameters.This work was financially supported by Associate Laboratory
LSRE-LCM (UID/EQU/50020/2019) funded by national funds
through FCT/MCTES (PIDDAC), and Foundation for Science and
Technology (FCT, Portugal). CIMO (UID/AGR/00690/2019) through
FEDER under Program PT2020. Authors thank CAPES (Brazil), CNPq
(Brazil) and Fundação Araucária (Brazil) for the support.info:eu-repo/semantics/publishedVersio
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