Agar extraction from integrated multitrophic aquacultured Gracilaria vermiculophylla: Evaluation of a microwave-assisted process using response surface methodology

Microwave-assisted extraction (MAE) of agar from Gracilaria vermiculophylla, produced in an integrated multitrophic aquaculture (IMTA) system, from Ria de Aveiro (northwestern Portugal), was tested and optimized using response surface methodology. The influence of the MAE operational parameters (extraction time, temperature, solvent volume and stirring speed) on the physical and chemical properties of agar (yield, gel strength, gelling and melting temperatures, as well as, sulphate and 3,6-anhydro-Lgalactose contents) was evaluated in a 2^4 orthogonal composite design. The quality of the extracted agar compared favorably with the attained using traditional extraction (2 h at 85ºC) while reducing drastically extraction time, solvent consumption and waste disposal requirements. Agar MAE optimum results were: an yield of 14.4 ± 0.4%, a gel strength of 1331 ± 51 g/cm2, 40.7 ± 0.2 _C gelling temperature, 93.1 ± 0.5ºC melting temperature, 1.73 ± 0.13% sulfate content and 39.4 ± 0.3% 3,6-anhydro-L-galactose content. Furthermore, this study suggests the feasibility of the exploitation of G. vermiculophylla grew in IMTA systems for agar production

Rheological characterization of gels from whey protein hydrolysates

The gelling ability of whey proteins can be changed by limited hydrolysis, and depending on the environmental conditions it can either be improved or impaired. Rheological studies are useful to evaluate the gelling ability of biological macromolecules; in particular, they allow accessing the structure of the gel, evaluating its texture, controlling the gelling behaviour or complementing the information provided by sensory methods. The heat-induced gelling properties of whey protein concentrate (WPC) and whey protein hydrolysates (WPH) from trypsin and pepsin with different degrees of hydrolysis - 1.0 (T1.0) and 3.5 % (T3.5) for tryptic hydrolysates and 1.5 (P1.5), 2.5 (P2.5) and 4.9 % (P4.9) for peptic hydrolysates - at different concentrations were studied at pH 7.0 by small deformation rheology. At WPC concentrations close to the gelling point, stronger gels with lower gelation temperatures were achieved with limited hydrolysis of whey proteins. G was higher for P1.5 (138 Pa) followed by P2.5 (58 Pa) and T1 (17 Pa), for hydrolysates concentration of 7.5 % w/w. All three were stronger than WPC at this concentration (G=5.7 Pa). They were also more elastic as the loss angle was smaller. However, at higher protein concentrations this effect was impaired. The expected increase in gel strength was smaller for the hydrolysates than for the intact proteins. A similar increase in protein concentration corresponds to a lower increase of the amount of protein with effective gelation ability in the case of the hydrolysates. Gels from hydrolysates ruptured at lower strains than gels from WPC (i.e. more particulate gels with a coarser network structure). The results show that protein systems with many different textures can be tailored by manipulating the hydrolysis conditions and the type of the enzyme used to produce protein hydrolysates.info:eu-repo/semantics/publishedVersio

Analysis of polycyclic aromatic hydrocarbons in fish: optimisation and validation of microwave-assisted extraction

An accurate and sensitive method for determination of 18 polycyclic aromatic hydrocarbons (PAHs) (16 PAHs considered by USEPA as priority pollutants, dibenzo[a,l]pyrene and benzo[j]fluoranthene) in fish samples was validated. Analysis was performed by microwave-assisted extraction and liquid chromatography with photodiode array and fluorescence detection. Response surface methodology was used to find the optimal extraction parameters. Validation of the overall methodology was performed by spiking assays at four levels and using SRM 2977. Quantification limits ranging from 0.15–27.16 ng/g wet weight were obtained. The established method was applied in edible tissues of three commonly consumed and commercially valuable fish species (sardine, chub mackerel and horse mackerel) originated from Atlantic Ocean. Variable levels of naphthalene (1.03–2.95 ng/g wet weight), fluorene (0.34–1.09 ng/g wet weight) and phenanthrene (0.34–3.54 ng/g wet weight) were detected in the analysed samples. None of the samples contained detectable amounts of benzo[a]pyrene, the marker used for evaluating the occurrence and carcinogenic effects of PAHs in food

Determination of ochratoxin A in bread: evaluation of microwave-assisted extraction using an orthogonal composite design coupled with response surface methodology

An analytical method using microwave-assisted extraction (MAE) and liquid chromatography (LC) with fluorescence detection (FD) for the determination of ochratoxin A (OTA) in bread samples is described. A 24 orthogonal composite design coupled with response surface methodology was used to study the influence of MAE parameters (extraction time, temperature, solvent volume, and stirring speed) in order to maximize OTA recovery. The optimized MAE conditions were the following: 25 mL of acetonitrile, 10 min of extraction, at 80 °C, and maximum stirring speed. Validation of the overall methodology was performed by spiking assays at five levels (0.1–3.00 ng/g). The quantification limit was 0.005 ng/g. The established method was then applied to 64 bread samples (wheat, maize, and wheat/maize bread) collected in Oporto region (Northern Portugal). OTAwas detected in 84 % of the samples with a maximum value of 2.87 ng/g below the European maximum limit established for OTA in cereal products of 3 ng/g

Gold nanoparticles functionalised with fast water exchanging Gd3+ chelates: linker effects on the relaxivity.

This is the accepted manuscript. The final version is available at http://dx.doi.org/10.1039/C4DT03210AThe relaxivity displayed by Gd(3+) chelates immobilized onto gold nanoparticles is the result of the complex interplay between the nanoparticle size, the water exchange rate and the chelate structure. In this work we study the effect of the length of ω-thioalkyl linkers, anchoring fast water exchanging Gd(3+) chelates onto gold nanoparticles, on the relaxivity of the immobilized chelates. Gold nanoparticles functionalized with Gd(3+) chelates of mercaptoundecanoyl and lipoyl amide conjugates of the DO3A-N-(α-amino)propionate chelator were prepared and studied as potential CA for MRI. High relaxivities per chelate, of the order of magnitude 28-38 mM(-1) s(-1) (30 MHz, 25 °C), were attained thanks to simultaneous optimization of the rotational correlation time and of the water exchange rate. Fast local rotational motions of the immobilized chelates around connecting linkers (internal flexibility) still limit the attainable relaxivity. The degree of internal flexibility of the immobilized chelates seems not to be correlated with the length of the connecting linkers. Biodistribution and MRI studies in mice suggest that the in vivo behavior of the gold nanoparticles was determined mainly by size. Small nanoparticles (HD = 3.9 nm) undergo fast renal clearance and avoidance of the RES organs while larger nanoparticles (HD = 4.8 nm) undergo predominantly hepatobiliary excretion. High relaxivities, allied to chelate and nanoparticle stability and fast renal clearance in vivo suggest that functionalized gold nanoparticles hold great potential for further investigation as MRI contrast agents. This study contributes to a better understanding of the effect of linker length on the relaxivity of gold nanoparticles functionalized with Gd(3+) complexes. It is a relevant contribution towards "design rules" for nanostructures functionalized with Gd(3+) chelates as Contrast Agents for MRI and multimodal imaging.This work was financially supported by Fundação para a Ciência e a Tecnologia, Portugal: PhD grant SFRH/BD/63994/2009 to Miguel Ferreira and Sabbatical Grant SFRH/BSAB/1328/2013 to José Martins at Bath University, UK; and Rede Nacional de NMR (REDE/1517/RMN/2005) for the acquisition of the Varian VNMRS 600 NMR spectrometer in Coimbra. T.B.R. was supported by a Marie Curie Fellowship (FP/- PEOPLE-2009-IEF 254380) and an EMBO Fellowship (ALTF 1145-2009). Financial support from Ministerio de Ciencia e Innovación, Spain, projects SAF2011-23622 (S.C.) and CTQ2010-20960-C02-02 (P.L.-L.), and Comunidad de Madrid, Spain, project S2010/BMD-2349 (S.C. and P.L.-L), is also acknowledged. B. Mousavi and L. Helm acknowledge financial support by the Swiss National Science Foundation. This work was carried out in the frame of the COST D38 Action “Metal Based Systems for Molecular Imaging” and COST TD1004 Action “Theranostics Imaging and Therapy”

Characterization of agar from Gracilaria tikvahiae cultivated for nutrient bioextraction in open water farms

Gracilaria tikvahiae, an endemic western North Atlantic red alga, was cultivated for nutrient bioextraction in urbanized estuarine waters in Long Island Sound and the Bronx River Estuary, USA. This study assesses the feasibility of an integrated approach of using G. tikvahiae produced in this bioextraction system as sustainable biomass source for agar production. Agars were extracted after alkaline pre-treatment and characterized in terms of gelling strength, chemical composition, chemical structure and gel structure. Results indicated that this seaweed performed similar to other cultivated Gracilaria in terms of extraction yield and gelling strength of the agar. Differences between sites were not significant in terms of agar gel strength, though yield was higher at Long Island Sound. The extracted agars were sulfated, methylated and with no detectable pyruvate substituents. It is possible to use an integrated strategy of nutrient bioextraction in urbanized estuarine waters and agar exploitation with G. tikvahiae.NFWF -Ministry of Education(8012.08.030370)info:eu-repo/semantics/publishedVersio

Rheological characterization of xanthan/galactomannans and kappa-carrageenan/galactomannans interactions: Comparison of galactomannans from nontraditional sources with conventional galactomannans

Led by consumers demands, food industry shows a growing interest in the formulation of mixed polysaccharide systems, leading to final products having specific properties and possibly cost advantages. In many systems, the combination of two polysaccharides gives rise to strong synergistic effects. Gels formed by galactomannans (mainly guar gum (GG) and locust bean gum (LBG)) and xanthan or kappa-carrageenan already find extensive applications. In the present work the synergistic interactions of two non-conventional galactomannans (extracted from Gleditsia triacanthos and Sophora japonica seeds) with xanthan and kappa-carrageenan were studied and compared with those obtained with traditional galactomannans (GG and LBG), in order to investigate their ability to provide novel properties to food products and to evaluate their effectiveness as alternative galactomannan sources. This was done by determining the rheological behavior (through dynamic oscillatory measurements) of xanthan/galactomannans and kappa-carrageenan/galactomannans mixtures and evaluating the effects of polymers concentration and temperature in the interaction strength, measured in terms of elastic module. For xanthan/galactomannans systems the maximum synergies were obtained for ratios of 20/80 xanthan/Gleditsia triacanthos galactomannan, 20/80 xanthan/Sophora japonica galactomannan, 40/60 xanthan/GG and 50/50 xanthan/LBG. For kappa-carrageenan/galactomannans mixtures the maximum synergies were obtained for 60/40 kappa-carrageenan/Gleditsia triacanthos galactomannan, 40/60 kappa-carrageenan/Sophora japonica galactomannan, 80/20 kappa-carrageenan/GG and 60/40 kappa-carrageenan/LBG. The higher degrees of synergism were obtained for Sophora japonica galactomannan and LBG followed by Gleditsia triacanthos galactomannan and GG (mannose/galactose ratios of 5/1, 4/1, 3/1 and 2/1, respectively). The differences observed in the gels rheological behavior suggest a dependence upon the fine structure of the galactomannan chain. A decrease of gelling and fusion temperatures was observed for increasing galactomannans concentrations and for decreasing galactomannans mannose/galactose ratio. The results point at a very interesting synergies between the non-conventional galactomannans and xanthan or kappa-carrageenan which can presumably be used in the development of food products with novel properties.info:eu-repo/semantics/publishedVersio

How much syntax is there in Metalinguistic Negation?

This paper explores the syntax of unambiguous metalinguistic negation (MN) markers in European Portuguese (EP) with the main goal of demonstrating the syntactic import of MN. Taking the EP facts as a means to gain insight into the grammatical encoding of MN in natural language, the paper shows that unambiguous MN markers split into two types: peripheral and internal. This split is confirmed by their contrasting behavior with respect to different syntactic tests, e.g.: availability in isolation and nominal fragments; ability to take scope over negation and emphatic/contrastive high constituents; compatibility with VP Ellipsis. Peripheral MN markers respond positively to all the tests, whereas internal ones respond negatively. These facts are derived from a syntactic analysis where CP plays a central and unifying role. It is proposed that while the cross-linguistically pervasive peripheral MN markers directly merge into Spec,CP, the more unusual sentence-internal MN markers are rooted in the TP domain and reach Spec,CP by movement. The centrality of the CP field is motivated by elaborating on Farkas and Bruce’s (2010) model of polarity features. Under the hypothesis that besides the relative polarity features [same] and [reverse], there is a feature [objection] that singles out MN declaratives among responding assertions, this is taken to be the edge feature that drives unambiguous MN markers into the CP space.info:eu-repo/semantics/publishedVersio

Efeitos do exercício resistido - er sobre a força e o estado saúde em individuos com paraplegia: uma revisão integrativa: Effects of resistance exercise - er on strength and health status in individuals with paraplegia: an integrative review

O Exercício Resistido (ER) promove benefícios efetivos para os praticantes com paraplegia no que se refere ao aspecto funcional, fisiológico e psicológico. Os Indivíduos com paraplegia na sua maioria são sedentários por conta de suas limitações físicas e consequentemente desenvolvem alterações metabólicas e hormonais, diminuindo consideravelmente sua Qualidade de Vida (QV). O objetivo da presente revisão foi descrever os efeitos benéficos do ER nas variáveis de condicionamento físico, força muscular e saúde dos indivíduos com paraplegia. Foram utilizadas as bases de dados Biblioteca virtual de saúde, PEDRO e PUBMED como local de busca da documentação bibliográfica publicada entre os anos de 2012 a 2022 utilizando os seguintes descritores Exercício físico, treinamento de força, exercício de reabilitação e Paraplegia. Os resultados demonstraram que um programa de treinamento físico de força promove efeitos benéficos em indivíduos com paraplegia, aumento de força, diminuição na dor de ombros, melhora na independência funcional, aumento de massa muscular, diminuição de gordura corporal e parâmetros bioquímicos e melhora na QV

Estudos Artísticos

Arte: ativar o humano. Dentro do desafio do “Congresso CSO, Criadores Sobre outras Obras,”– em que artistas são chamados a escrever sobre a obra de outros artistas, no âmbito dos países de língua portuguesa ou espanhola, – a Revista Croma interessa-se pelas instâncias de intervenção, implicação, aproximação junto das comunidades, de excluídos, de comunidades menos diferenciadas. Há um vasto campo de ação onde têm surgido movimentos para novas relações, conhecimentos, atitudes e práticas. Se a dimensão relacional tem vindo a ser problematizada com maior insistência no contexto da crítica contemporânea, especialmente na vertente que se debruça sobre o efeito ideológico do orientalismo e da realidade pós-colonial, então os 16 artigos que se alinham nesta edição fornecem leituras alternativas sobre as dinâmicas da arte contemporânea. Sobre as relações sociais tecem-se ligações intermediadoras. Os seus resultados habitam as cidades, geram novas formas de pensar, renovam discursos, promovem identidade. Trata-se de habitar de novo os espaços vazios, de ativar o humano, que é também onde se podem encontrar as novas formulações artísticas.info:eu-repo/semantics/publishedVersio