Artigos em revistas internacionais_ESAS
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- Active center determination of ethylene polymerisation catalysts using a quenching method with tritiated methanolPublication . Justino, Jorge; Dias, A.R.; Tait, J.P.The subject of this work is ethylene polymerisation using Kaminsky type catalysts: Cp2MR2=methylaluminoxane [M=Zr,W,Nb; R=Cl,CH3]. Active center determination and kinetic studies of the (Cp2WCl2 + methylaluminoxane) and Cp2ZrCl2 + methylaluminoxane) systems are described, using a quenching method with tritiated methanol. The activity of the polymer was determined by liquid scintillation counting. We have found 0.5% and 87% of active centers, respectively for W and Zr system. The catalytic activity of complexes Cp2WCl2 and Cp2NbCl2 was compared with that of Cp2ZrCl2. The W and Nb complexes are found to be less active than the Zr complex.
- Alicyclobacillus acidoterrestris spores in fruit products and design of pasteurization processesPublication . Silva, Filipa V.M.; Gibbs, P.Alicyclobacillus acidoterrestris is a thermoacidophilic, nonpathogenic and sporeforming bacterium which has been found in commercial pasteurized fruit juices in the past. Only few and recent studies were available in the literature, since only in 1984 Cerny et al. [Cerny, G., Hennlich, W., & Poralla, K. (1984). Fruchtsaftverderb durch bacillen: isolierung und charakterisierung des verderbserregers. Z. Lebensmitt. Unters. Forsch. 179, 224-227] reported a spoiled aseptically packaged apple juice with A. acidoterrestris and in 1987 Deinhard et al. [Deinhard, G., Blanz, P., Poralla, K., & Altan, E. (1987). Bacillus acidoterrestris sp. nov., a new thermotolerant acidophile isolated from different soils. Systematic and Applied Microbiology, 10, 47-53] named first this species. Detection and identification methods for A. acidoterrestris were reviewed and data regarding heat resistance of spores and growth in fruits were collected. Finally, a new methodology to design pasteurization processes for high acidic fruit products is presented.
- Alkyl deoxy-arabino-hexopyranosides: synthesis, surface properties, and biological activitiesPublication . Silva, Filipa; Goulart, Margarida; Justino, Jorge; Neves, Ana; Santos, F.; Caio, J.; Lucas, S.; Newton, A.; Sacoto, D.; Barbosa, E.; Santos, M. S.; Rauter, A. P.Octyl and dodecyl glycosides possessing 2-deoxy-arabino-hexopyranoside moieties belonging to the D-and L-series in their alpha- and beta-forms were synthesized by reaction of an acetyl protected glycal with octanol or dodecanol, catalyzed by triphenylphosphine hydrobromide, followed by deprotection. Their surface properties were studied and discussed in terms of the adsorption and aggregation parameters, pC(20), CMC, and gamma(CMC). The antimicrobial activities were assessed using the paper disk diffusion and broth dilution methods. Both the octyl and dodecyl 2-deoxy beta-D-glycosides inhibited significantly Enterococcus faecalis, a microbe also highly susceptible to dodecyl 2,6-dideoxy-alpha-L-arabino-hexopyranoside. This compound was particularly active against Bacillus cereus and Bacillus subtilis, presenting for both Bacillus species a minimal inhibitory concentration of the same order of magnitude and a minimal lethal concentration even smaller than that obtained for chloramphenicol, a bioactivity which remained unaltered after 1 year solution storage at 4 degrees C. In addition, activity over Listeria monocytogenes was also observed. Direct cytotoxicity and genotoxicity of the glycosides were determined by proliferative index (mitotic index) evaluation in peripheral human lymphocytes of healthy donors. All compounds induced acute toxicity effects, and the response was dose dependent for the alpha-anomer of both the alkyl 2-deoxy-arabino-hexopyranosides and for the corresponding dodecyl beta-anomer, what suggests that non-toxic but still bioactive concentrations may be found for these compounds
- Análise da estrutura genética de populações ovinas churras portuguesasPublication . Santos-Silva, F.; Ivo, R.; Sousa, M. C.; Vicente, António; Carolino, M. I.; Carolino, Nuno; Gama, LuisA diversidade e estrutura genética foram estudadas em seis raças portuguesas do grupo Churro (Badana, Galega Bragançana, Galega Mirandesa, Mondegueira, Churra da Terra Quente e Algarvia), e na raça exótica Assaf, com um conjunto de 20 microssatélites. Os dados foram analisados com a metodologia bayesiana implementada pelo software STRUCTURE. A variabilidade genética observada sugere a existência de quatro populações ancestrais na sua origem. As raças Assaf e Algarvia estão bem identificadas com populações ancestrais distintas, o que resultará do seu distanciamento geográfico relativamente às restantes raças. As outras raças Churras, cuja área de exploração é o Norte de Portugal, mostram um grau de diferenciação reduzido, e resultam de duas populações ancestrais que contribuem em maior ou menor proporção para cada raça, o que indica que provavelmente terá existido fluxo de genes entre estas raças.
- Angler’s preferences, perceptions and practices regarding non-native freshwater fishPublication . Banha, F.; Gago, João; Margalejo, D.; Feijão, J.; Casals, F.; Anastácio, P.M.; Ribeiro, F.It is globally recognized that freshwater anglers can have a decisive role in promoting fish introductions. The aim of this study was to analyze fresh water anglers’ actions and perceptions regarding fish introductions, comparing two distinct situations, one with recently arrived non-natives fishes and another with older fish introductions, using the Iberian Peninsula as a case study. To achieve this goal, a bilingual survey was implemented on-line in Portugal and Spain and in person (direct inquiries) in two Iberian regions: Lower Ebro (older fsh introductions) in Spain; and Lower Tagus (recent fish introductions) in Portugal. Results showed spatial diferences in perceptions and actions, namely about the target species, awareness of the impact of non-native fishes, fish introductions reported and proportion of anglers that wanted new fish species. In the Ebro river there is a high percentage of foreign anglers, higher awareness of fish introduction impact and lower introduction rates reported than in the Tagus river. However, popularity of non-native species like European catfish, was higher in the Ebro. In general, although risk behaviors such as use of fish as life bait was of low prevalence for both countries (approx. 5%), it corresponds to large numbers of fish being introduced. Our conservative estimates revealed 273,600 events of bait discharge per year. Regarding the intentional introductions, we estimated a total of 140,000 intentional introduction (illegal) events per year. These findings may help to improve monitoring, awareness and fisheries management programs led by governmental agencies.
- Antihyperglycaemic and protective effects of flavonoids on streptozotocin-induced diabetic ratsPublication . Rauter, A. P.; Martins, A.; Borges, C.; Mota-Filipe, H.; Pinto, R.; Justino, JorgeThe antihyperglycaemic effect of eight standard flavonoids, previously identified in the ethanol extract of the claimed antidiabetic plant Genista tenera, was evaluated on streptozotocin (STZ)-induced diabetic Wistar rats. The aglycones apigenin, chrysoeriol and genistein, the monoglucosides apigenin 7-O-glucoside, luteolin 7-O-glucoside and genistein 7-O-glucoside and the diglycosides rutin and luteolin 7,3′-di-O-glucoside were administered i.p. for 7 days (4 mg/kg b.w./day). The protective effect of these compounds over liver and kidneys of STZ–diabetic models was also evaluated by the determination of seric AST, ALT and urea levels. After 7 days of treatment, apigenin, chrysoeriol and genistein significantly lowered the blood glucose levels of diabetic animals; this effect was more pronounced (P < 0.01) in the oral glucose tolerance test. Glucose tolerance was also significantly improved in the rutin (P < 0.01) and in the genistein 7–O–glucoside (P < 0.05) treated groups. In addition, almost all the tested compounds effectively protected the liver and kidneys against STZ-induced damage in rats
- Aquatic plants in the rice fields of the Tagus Valley, PortugalPublication . Vasconcelos, T.; Tavares, M.; Gaspar, NatáliaIn 1997, in 50 surveys of irrigated rice fields (Oryza sativa L.), 47 species of vascular plants were recorded in 19 families. Most of the species belonged to the Gramineae and Cyperaceae families. Seven species of algae were found, mostly Hydrodictyon reticulatum (42%) and Chara vulgaris (38%). Echinochloa crus-galli and Paspalum paspalodes showed a relative frequency of 98% and 82%, respectively. An interpretation of the major factors is presented influencing weed distribution. Amongst the weeds recorded, 13 were alien species. For these alien species the probable date of introduction into Portugal and into rice fields was determined. The recently introduced neophytes Heteranthera limosa and Heteranthera reniformis and the increasing presence of red rice (Oryza sativa), represent a potential danger to rice culture.
- Assessment of Subjective Well-Being in a Cohort of University Students and Staff Members: Association with Physical Activity and Outdoor Leisure Time during the COVID-19 PandemicPublication . Quarta, Stefano; Levante, Annalisa; García-Conesa, María-Teresa; Lecciso, Flavia; Scoditti, Egeria; Carluccio, Maria Annunziata; Calabriso, Nadia; Damiano, Fabrizio; Santarpino, Giuseppe; Verri, Tiziano; Pinto, Paula; Siculella, Luisa; Massaro, MarikaTime spent outdoors and physical activity (PA) promote mental health. To confirm this relationship in the aftermath of COVID-19 lockdowns, we explored individual levels of anxiety, depression, stress and subjective well-being (SWB) in a cohort of academic students and staff members and tested their association with sport practice, PA at leisure time and time spent outdoors. Our cross-sectional study collected data during the COVID-19 outbreak (April–May 2021) on 939 students and on 238 employees, who completed an online survey on sociodemographic and lifestyle features, depression, anxiety, stress, and SWB. Results showed that the students exhibited higher levels of anxiety, depression, and stress, and lower levels of SWB (p< 0.001 for all domains) compared to the staff members. Correlation analysis confirmed that PA and time spent in nature were associated to high mental health scores among staff and, more consistently, among students. Finally, mediation analyses indicated that the time spent in nature, social relationships, and levels of energy play a mediator role in the relationship between sport practice and SWB. Our evidence reinforces the protective role of time spent in nature in improving mental health, and providessupport for policymakers to make appropriate choices for a better management of COVID-19 pandemic consequences.
- Association between Mediterranean lifestyle and perception of well-being and distress in a sample population of university Italian studentsPublication . Quarta, S.; Siculella, L.; Levante, A.; Carluccio, M.A.; Calabriso, N.; Scoditti, E.; Damiano, F.; Lecciso, F.; Pinto, Paula; García-Conesa, M.T.; Pollice, F.; Massaro, M.We investigated the extent to which adherence to the Mediterranean diet (MD) in combination with Mediterranean lifestyle factors influenced students’ perceptions of subjective well-being (SWB) and distress. 939 undergraduates completed a survey to assess sociodemographic and lifestyle characteristics, including adherence to the MD, depression, anxiety, stress, and SWB. Data were analysed with correlation, logistic, and multiple linear regression models. Higher adherence to MD correlated with better SWB. Fruit, red meat, sweet and caffeinated beverages contributed significantly. However, it was the combination of adherence to MD with other factors, including quality of social relationships, income, smoking, sleep, and physical activity that better predicted SWB. Our results confirm the positive influence of MD on SWB. However, they also suggest the need to consider perceptions of well-being by a more holistic approach that considers physical and social factors simultaneously to improve the development of more effective educational and motivational programmes.
- Autochthonous Starter Cultures Are Able to Reduce Biogenic Amines in a Traditional Portuguese Smoked Fermented SausagePublication . Dias, Igor; Laranjo, Marta; Potes, Maria Eduarda; Agulheiro-Santos, Ana Cristina; Ricardo-Rodrigues, Sara; Fialho, Ana Rita; Véstia, Joana; Fraqueza, Maria João; Oliveira, Margarida; Elias, MiguelTraditional smoked fermented sausages are highly appreciated in Portugal and are mostly manufactured according to traditional procedures. The aim of the present work was to evaluate the effect of autochthonous starter cultures on the safety and quality of a smoked fermented sausage, Painho da Beira Baixa (PBB), preserving its sensory quality. Physicochemical parameters, namely pH and water activity (aW), microbiological parameters, biogenic amines, colour, texture profile and sensory attributes were assessed. Different starters were selected based on our previous work. Staphylococcus equorum S2M7, Staphylococcus xylosus CECT7057, Lactobacillus sakei CV3C2, Lactobacillus sakei CECT7056 and a yeast strain (2RB4) were co-inoculated in meat batters at defined concentrations. Starters had a significant effect on the reduction of pH. Enterobacteria and Listeria monocytogenes were not detected in inoculated end-product sausages. Moreover, sausages inoculated with S. equorum S2M7/L. sakei CV3C2/yeast 2RB4 showed a significant reduction in the total content of biogenic amines. No significant differences between treatments were observed for colour and texture parameters, except for adhesiveness. The studied starters did not compromise the sensory characteristics of PBB. To our knowledge, this is the first comprehensive study on the quality and safety of this type of smoked fermented sausage from the central region of Portugal.