Screening for angiotensin I-converting enzyme (ACE) inhibitory activity of enzymatic hydrolysates obtained from Azorean macroalgae

As part of ongoing studies into the isolation of antihypertensive peptides, 12 common macroalgae species from Azores were investigated for their potential angiotensinconverting enzyme (ACE) inhibitory properties. After optimization of enzymatic hydrolysis conditions, the anti-ACE activity was determined by high performance liquid chromatography (HPLC). The species under study include four Rhodophyta (Gelidium microdon, Osmundea pinnatifida, Porphyra sp. and Pterocladiella capillacea), four Chlorophyta (Chaetomorpha linum, Codium adhaerens, Ulva compressa and Ulva rigida) and four Heterokontophyta (Cystoseira humilis, Fucus spiralis, Padina pavonica and Sargassum cymosum). The bromelain hydrolysates derived from P. capillacea, Porphyra sp., F. spiralis, U. compressa, O. pinnatifida and U. rigida were the most active presenting an ACE inhibitory activity of 48.73 ± 1.58%, 50.96 ± 1.82%, 56.77 ± 1.80%, 59.80 ± 0.95%, 62.59 ± 1.60% and 65.68 ± 0.72%, respectively. These results suggest that some macroalgae from the littoral Azorean sea are potential sources of powerful ACE inhibitor peptides, with potential impact on public health, particularly on the hypertensive patients. These features make these algae valuable to the regional economy and may also provide an incentive for marine biodiversity conservation and valuation of marine algal resources

Potencial impacto do chá da Camellia sinensis na atenuação dos efeitos negativos do covid-19

A secção UAciência é coordenada pelo Professor Universitário Armindo Rodrigues.Um número crescente de publicações científicas sugere que os polifenóis, caracterizados por possuírem um ou mais núcleos aromáticos contendo substituintes hidroxilados, são os compostos mais abundantes nas folhas da Camellia sinensis, representando cerca de 30-36% do seu peso seco. Estes metabolitos (flavonóides e particularmente flavonóis, flavanóis e metilxantinas) são alguns dos ingredientes naturais capazes de “travar” a ação dos radicais livres e, consequentemente de retardar o progresso das doenças mais preocupantes da nossa sociedade. Desde a última década tem havido um grande interesse, potenciado por estudos epidemiológicos, em estudar os efeitos fisiológicos dos polifenóis do chá, […].info:eu-repo/semantics/publishedVersio

Autoeficacia y utilidad percibida como condiciones necesarias para un aprendizaje académico autorregulado

En el marco de la teoría social cognitiva, en este trabajo se in-vestiga en qué medida el rendimiento escolar (Lengua y Matemáticas) puede ser explicado por el uso de estrategias de aprendizaje autorregulado y cómo este tipo de comportamiento deseable puede estar condicionado por la utilidad percibida de su uso y por la competencia percibida para su ejecución. Para completar el modelo de ecuaciones estructurales, se plan-tea que los niveles de estas variables hipotéticamente centrales en el aprendizaje están significativamente influenciados por el tiempo de estu-dio, el curso actual y el grado de fracaso escolar (número de cursos repeti-dos). El ajuste del modelo se ha llevado a cabo en base a una muestra de 750 estudiantes de enseñanza básica (entre 12 y 15 años) seleccionados aleatoriamente por grupo de un total de diez colegios. Los resultados ob-tenidos muestran, en la dirección de lo hipotetizado, que a mayor uso de estrategias de autorregulación del proceso de aprendizaje mayor es el ren-dimiento, y viceversa, y que el uso de dichas estrategias depende fuerte-mente de la utilidad percibida de tal comportamiento y de la auto-eficacia para su uso efectivo. Estos datos sugieren la importancia de que los profe-sores utilicen estrategias de autorregulación en las tareas previstas en el currículo, aplicándolas a situaciones concretas de aprendizaje y entrenando su transferencia para otros contextos y tareas escolares, ya que esto hará más visible su utilidad y la práctica generará competencia percibida en los alumnos.Grounded on the social cognitive perspective, the current in-vestigation aims at evaluating, through a structural equation model, the extent to which school achievement (Portuguese and Math) can be ex-plained by using self-regulated learning strategies and how those self-regulated behaviors can be affected by perceived instrumentality as well as by students’ perceived competence to manage learning strategies ade-quately. In order to develop the structural equation model the hypothe-sized learning variables previously referred are supposed to be significant-ly affected by students’ study time, grade level and school underachieve-ment (number of years failed at school). The EQS model has been devel-oped with a sample of 750 Portuguese students attending compulsory education (12 to 15 years old) randomly selected among a larger group of students from ten different schools. Data confirm the importance of teachers’ using embedded self-regulated strategies in the academic tasks assigned to their students, promoting their transference to other contexts and different academic activities, once this teaching practice will be a pri-vileged way to make learning strategies’ usefulness clear and to ensure the promotion of students’ perceived competence. Key words: self-regulated learning; compulsory education; school suc-cess; self-efficacy; perceived instrumentality; structural equation modeling

Antioxidant activity of macroalgae from the Azores

Free radical scavenging activity (FRSA) was studied to determine the antioxidant activity of 8 common macroalgae species found in the Azores. Species under study were Porphyra sp., Osmundea pinnatifida, Pterocladiella capillacea, Sphaerococcus coronopifolius and Gelidium microdon, from Rhodophyta; Ulva compressa and Chaetomorpha pachynema, from Chlorophyta and Fucus spiralis from Phaeophyta.The antioxidant activity was evaluated in methanolic extract by a decolourisation solution test of 2,2-diphenyl-1-picrylhydrazyl (DPPH), used as a stable radical. The methanolic extracts were obtained from dried biomass by sequential extractions, attaining a final concentration of 2 mg.mL-1. The FRSA values ranged from 19.54% for S. coronopifolius to 60.05% for F. spiralis with standard deviation (SD) varying between 1.41% and 6.80%. Results indicated that the studied seaweeds are a very promising source of biological active compounds with antioxidante properties. The seaweeds were collected in the Azorean islands where seawater pollution levels are low. Consequently, these seaweeds represent a valuable and good source of antioxidante material with superior beneficial effects on human health

Biotechnological applications of selected macroalgae

IBBA Strategic Planning - Workshop III, Plant Biotechnology Ponta Delgada, 25 Janeiro, 2011

Nutritional value of selected macroalgae

Copyright © Springer Science+Business Media B.V. 2011.Macroalgae are traditionally used in human and animal nutrition. Their protein and fiber content have been widely studied and differ according to the species, their geographic origin and their seasonal conditions. In addition to their value for human nutrition, seaweeds have multiple therapeutically applications (e.g., weight control, hypocholesterolemic, antioxidant and antitumor activities, others) and, in general, contribute and promote human health. In the archipelago of the Azores, the consumption of seaweeds is widespread and accepted as a common practice in some islands. This work is aimed at providing information on the protein and fiber content of the locally consumed species, to promote this regional food product that can be potentially profitable from the biotechnology and commercial perspective, and also benefit public health, particularly, taking into account the low level of marine pollution in the Azores archipelago. Protein and fiber content of eight seaweeds (Porphyra sp., Osmundea pinnatifida, Pterocladiella capillacea, Sphaerococcus coronopifolius, and Gelidium microdon, Rhodophyta; Cystoseira abies-marina and Fucus spiralis, Phaeophyta; Ulva compressa, Chlorophyta) were determined using the Kjeldahl method and the Weende method, respectively. The protein content ranged from 6.81 to 26.62 of dry weight for C. abies-marina and U. compressa, respectively. Fiber content was generally higher as compared with that in seaweeds from other origins and ranged from 33.82 to 63.88 for O. pinnatifida and F. spiralis, respectively

Avaliação de dimensões psicológicas nos comportamentos de exercício e actividade física em estudantes universitários : características psicométricas de medidas de atitudes e estados de humor associados à prática desportiva

Apesar dos benefícios da evidência para os benefícios do exercício e da actividade física, nomeadamente nos estados de humor e afectivos, a investigação actual evidencia que o número de indivíduos envolvidos na sua prática, de uma forma regular e sistemática, é ainda insuficiente, encontrando-se ainda longe dos valores recomendados e/ou desejáveis. Entre outras dimensões psicológicas, as atitudes face ao exercício parecem constituir um factor central e determinante em tal envolvimento e prática. No âmbito de um projecto de investigação longitudinal mais vasto, em curso na Universidade do Minho, apresentam-se dados preliminares da avaliação das atitudes face ao exercício e dos estados de humor associados à prática de exercício físico, junto de uma amostra inicial de mais de 1.800 jovens estudantes universitários (1º ano), de todos os cursos da Universidade do Minho. Os participantes no estudo constituem assim uma amostra significativa de jovens estudantes em plena transição académica e no início do seu novo ciclo de estudos (ensino superior). Esta apresentação tem como objectivo central a análise de resultados preliminares relativos às propriedades psicométricas (e.g., estrutura factorial, consistência interna e validade), de dois instrumentos de avaliação psicológica que integram a “Escala de Comportamentos e Atitudes Face ao Exercício Físico” utilizada neste projecto de investigação (Cruz & Gomes, 2006): a “Escala de Atitudes Face ao Exercício” (EAFE) e uma versão portuguesa do “Profile of Mood States – POMS” (McNair, Lorr, & Droppleman, 1981; Cruz & Mota, 1997). Tais resultados parecem evidenciar as boas características psicométricas de ambos os instrumentos, fornecendo apoio adicional para a utilidade e validade do seu uso no domínio da Psicologia do Desporto, do Exercício e da Saúde, em geral. Adicionalmente, enfatizam-se e discutem-se, entre outras, as diferenças observadas entre praticantes e não praticantes de exercício regular, bem como as vantagens e benefícios da implementação de programas de promoção do exercício e actividade física junto da população universitária

G_2 cosmological models separable in non-comoving coordinates

We study new separable orthogonally transitive abelian G_2 on S_2 models with two mutually orthogonal integrable Killing vector fields. For this purpose we consider separability of the metric functions in a coordinate system in which the velocity vector field of the perfect fluid does not take its canonical form, providing thereby solutions which are non-separable in comoving coordinates in general. Some interesting general features concerning this class of solutions are given. We provide a full classification for these models and present several families of explicit solutions with their properties.Comment: latex, 26 pages, accepted for publication in Class. Quantum Gra

Influence of micro-textures on cutting insert heat dissipation

Metal machining is one of the most important manufacturing processes in today’s production sector. The tools used in machining have been developed over the years to improve their performance, by reducing the cutting forces, the friction coefficient, and the heat generated during the cutting process. Several cooling systems have emerged as an effective way to remove the excessive heat generated from the chip-tool contact region. In recent years, the introduction of nano and micro-textures on the surface of tools has allowed to further improve their overall performance. However, there is not sufficient scientific data to clearly show how surface texturing can contribute to the reduction of tool temperature and identify its mechanisms. Therefore, this work proposes an experimental setup to study the tool surface characteristics’ impact on the heat transfer rate from the tools’ surface to the cooling fluid. Firstly, a numerical model is developed to mimic the heat energy flow from the tool. Next, the design variables were adjusted to get a linear system response and to achieve a fast steady-state thermal condition. Finally, the experimental device was implemented based on the optimized numerical model. A good agreement was obtained between the experimental tests and numerical simulations, validating the concept and the implementation of the experimental setup. A square grid pattern of 100 μm × 100 μm with grooves depths of 50, 100, and 150 μm was introduced on cutting insert surfaces by laser ablation. The experimental results show that there is a linear increase in heat transfer rate with the depth of the grooves relatively to a standard surface, with an increase of 3.77% for the depth of 150 μm. This is associated with the increase of the contact area with the coolant, the generation of greater fluid turbulence near the surface, and the enhancement of the surface wettability.This work was supported by FCT (Fundação para a Ciência e a Tecnologia) through the grant 2020.07155.BD and by the project POCI-01-0145-FEDER-030353 (SMARTCUT). Additionally, this work was supported by FCT national funds, under the national support to R&D units grant, through the reference projects UIDB/04436/2020 and UIDP/04436/2020

Potencial nutricional de macroalgas marinhas dos Açores. Determinação do teor de proteína.

IV Congresso da Ordem dos Biólogos e II Congresso dos Biólogos dos Açores (Painel Biologia Marinha e Oceanografia). Ponta Delgada, Açores, 13-15 de Outubro de 2011