1,069 research outputs found

    Antioxidant properties, total phenols and pollen analysis of propolis samples from Portugal

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    Pollen analysis, total phenols content and antioxidant activity were studied for the first time in Portuguese propolis samples from Bornes and Fundão regions. Total phenols content was determined by colorimetric assay and their amount was of 329 mg/g of GAE in Bornes sample and 151 mg/g of GAE in Fundão propolis. The antioxidant capacity of propolis extracts was assessed through the scavenging effects on DPPH (2,2- diphenyl-1-picrylhydrazyl) and reducing power of iron (III)/ ferricyanide complex assays. A concentration- dependent antioxidative capacity was verified in DPPH and reducing power assays. Low values of EC50 on DPPH scavenging assay were obtained for Bornes and Fundão propolis (of 6.22 lg/mL and 52.00 lg/mL, respectively). For reducing power the values were 9.00 lg/mL, for Bornes propolis, and 55.00 lg/mL, for Fundão propolis. The high activity of propolis from Bornes could be related with their different pollen composition. The results obtained indicate that Portuguese propolis is an important source of total phenols showing antioxidant properties that could be beneficial for human health

    Aplicação De Gesso E Vinhaça: Atributos Químicos Do Solo, Produtividade E Estado Nutricional Da Alfafa

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    The objective of this work was to evaluate the effects of the application of phosphogypsum and vinasse on soil chemical properties and productivity and nutritional characteristics of alfalfa (Medicago sativa). The experiment was conducted in a randomized block design, using a 3×5 factorial arrangement, with three vinasse rates (0, 150 and 300 m3 ha-1) and five phosphogypsum rates (0, 3, 6, 9 and 12 Mg ha-1). The alfalfa chemical composition and shoot dry matter (SDW) and soil chemical properties (in the layers 0.0-0.2 and 0.21-0.4 m) were evaluated. The vinasse rates increased the soil potassium contents, while the phosphogypsum rates promoted linear increases in soil calcium and sulfur contents. The base saturation was increased and the magnesium content showed a quadratic response on the layer 0.21-0.4 m with the increase in phosphogypsum rates. The calcium, magnesium and phosphorus contents in the alfalfa leaves were lower with vinasse application. The phosphogypsum rates promoted linear increases in alfalfa SDW. Vinasse rated 150 m3 ha-1 was been enough to SDW increase. Calcium and magnesium contents in the leaves fitted a quadratic model, with maximum calcium content in the phosphogypsum rate of 9.5 Mg ha-1 and the minimum magnesium content in the phosphogypsum rate of 8.7 Mg ha-1. The leaf sulfur contents in all vinasse rates and leaf potassium contents in the highest vinasse rate showed maximum accumulation at near 9 Mg ha-1 of phosphogypsum. © 2017, Universidade Federal Rural do Semi-Arid. All Rights Reserved.30121321

    Mathematical models to study the biological phosphorus flow in sheep fed increasing levels of mineral

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    Dois modelos compartimentais foram aplicados e comparados para avaliar o fluxo biológico de fósforo em ovinos que receberam dietas com níveis crescentes do mineral - 0, 2, 4 e 6g por dia. Foram utilizados 24 machos, da raça Santa Inês, com média de peso de 33,6kg. Foi utilizado fosfato bicálcico como fonte de fósforo e 32P como traçador. Avaliou-se o fluxo de fósforo entre os compartimentos: trato gastrintestinal, sangue, ossos e tecidos moles, além da ingestão, excreção e balanço do mineral. O incremento na ingestão de P aumentou a perda fecal do mineral. O fluxo de fósforo entre o trato gastrintestinal e o sangue e o fluxo contrário foram influenciados de forma quadrática pelo incremento na ingestão, diminuindo após a ingestão de 5,5g/dia, sem diferença entre os modelos avaliados. Os modelos estudados mostraram diferenças em relação ao fluxo entre sangue, ossos e tecidos moles, sem efeito dos tratamentos sobre o balanço geral do mineral, porém os níveis de ingestão praticados interferiram no fluxo biológico do fósforo. A disponibilidade biológica do fósforo ingerido diminuiu quando a ingestão superou a necessidade do animal, o que aumentou as excreções no ambiente. A quantificação do fluxo biológico de fósforo diferiu quando aplicados os modelos estudados em decorrência da sua estrutura.Two compartimental models were applied and compared to evaluate the biological flow of P in lambs fed diets containing increasing levels of P (0, 2, 4 and 6g per day). Twenty four Santa Inês lambs with liveweight of 33.6kg were used. Dicalcium phosphate was used as P source and 32P as a tracer. P flow between compartments (gastrointestinal tract, blood, bones and soft tissues), ingestion, excretion and the mineral balance were evaluated. The increase in P intake increased fecal P loss. P flow from gastrointestinal tract to blood stream and opposite flow were affected quadratically by increased P intake, decreasing after the ingestion of 5.5g/day, without a difference among models. The models studied showed differences regarding the P flow between blood, bone and soft tissues, however, the P balance was not affected by the treatments. The increased P levels interfered with the biological P flow in sheep. The bioavailability of P diet decreases when intake exceeds the animal requirement, increasing losses to the environment. The quantification of biological P flow was different between models due to the structure of each one.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)CNPqFAPEMI

    Volatile compounds contribution of Hanseniaspora guilliermondii and Hanseniaspora uvarum during red wine vinifications

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    This work aims to investigate the contribution of a selected non-Saccharomyces yeast species, Hanseniaspora guilliermondii, to higher alcohols, esters, fatty acids and heavy sulphur compounds composition of red wine. Red grape must vinifications of 100 l were performed and an inoculated fermentation with H. guilliermondii was compared to a spontaneous fermentation. The presence of apiculate yeasts was observed in both fermentations; however, Hanseniaspora uvarum was the only apiculate yeast isolated from the spontaneous fermentation. Apiculate yeasts dominated the fermentation until an ethanol concentration of 6% (v/v) was attained and remained in considerable high levels for an ethanol concentration of 12.5% (v/v). The grape must inoculated with H. guilliermondii led to the production of wine with higher concentrations of 1-propanol, 2-phenylethyl acetate and 3-(methylthio)propionic acid, and lower amounts of ethyl hexanoate, pentanoic acid, free fatty acids, 2-methyltetrahydrothiophen-3- one and acetic acid-3-(methylthio)propyl ester, than wine resulting from the spontaneous fermentation. The present study shows that the use of specific apiculate yeasts in grape must fermentations may lead to the production of wines with different chemical profiles, emphasising the importance of Hanseniaspora yeasts as mixed starter cultures with Saccharomyces cerevisiae, in winemaking.info:eu-repo/semantics/acceptedVersio

    Shelf-life extension of watermelon juice preserved by hyperbaric storage at room temperature compared to refrigeration

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    This work reports Hyperbaric Storage (HS) preservation of raw watermelon juice at variable/uncontrolled room temperature (RT,z21 C) for 7 days at 100 MPa and compared it with refrigeration (RF). At the end of storage, there was an increase in microbial counts (total aerobic mesophiles, psychrophiles, and yeasts and moulds) to above 6 log10 CFU/mL for samples stored at atmospheric pressure (RF and RT), while juice stored under HS/RT showed maximum values of about 2 log10 CFU/mL for total aerobic mesophiles/ psychrophiles and below the detection limit for yeasts and moulds. HS/RT juice showed also physicochemical parameters at levels similar to the initial juice. Thus, HS/RT can not only be used to preserve foods with no refrigeration energetic costs (since it does not require temperature control), but additionally, has also a great potential to extend the shelf-life of food products, compared to RF. This is the first case in the literature showing this additional potential/advantage of HS/RT

    Effect of the particle size range of construction and demolition waste on the fresh and hardened-state properties of fly ash-based geopolymer mortars with total replacement of sand

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    This study seeks the valorization of industrial residues (fly ash and construction and demolition waste (CDW)) through the production of geopolymer mortars. The effect of the sand substitution by CDW and the influence of the particle size range of CDW fine aggregates on the fresh and hardened properties of the mortars were evaluated. Geopolymer mortars were produced using biomass fly ash waste and metakaolin as a binder, CDW as fine aggregates, and an alkali solution of sodium silicate and sodium hydroxide as activator. The geopolymer mortars were characterized in fresh state by the flow table test and in the hardened state through chemical, physical/microstructural analyzes. The mortars produced with CDW showed lower flowability when compared to the ones prepared with sand. The compressive and flexural strength of hardened mortars, respectively, obtained with residues were higher when compared to sand: 40 MPa and 8.5 MPa with CDW, against 23 MPa and 3.1 MPa for sand-based samples. It was observed that mortars developed with recycled aggregate and natural aggregate present similar chemical and mineralogical compositions. The superior results obtained in the mechanical properties of mortars produced with CDW are related to the recycled aggregate-geopolymer paste interface.publishe

    Is true friendship possible on Facebook? A study from the psychological perspective of Laín Entralgo

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    The present work aims to analyse the meaning of the concept of friendship through the study of the work of the doctor and philosopher Pedro Laín Entralgo. The initial hypothesis of the study is that the concept of friendship has been used instrumentally by social media networks, and that these do not offer the conditions necessary to fully experience true friendship. To verify this, we focused on the study of the psychological dimensions of friendship proposed by the author, identifying a series of variables and conducting an analysis by means of a survey of university students who are active users of the platform. With these results the descriptive statistics were extracted and a nonparametric analysis was performed of the variables to determine if Facebook does in fact offer the conditions necessary for to experience true friendship in its psychological dimensions. As the results show, to experience true friendship on social networks is difficult, given that the nature of the interactions between users of the platform are not appropriate for this experience. In calling this different type of relationship friendship Facebook benefits from an attractive hook which leads users to generate contacts as a form of currency which benefits the business model of the social media platform. The concept of true friendship is altered, deformed and displaced in favour of other types of relationships.El presente trabajo tiene como objetivo analizar el significado del concepto de amistad a través del estudio de la obra del médico y filósofo Pedro Laín Entralgo. La hipótesis inicial del estudio es que el concepto de amistad ha sido utilizado instrumentalmente por las redes sociales, y que estas no ofrecen las condiciones necesarias para la vivencia plena de la verdadera amistad. Para comprobarlo, nos centramos en el estudio de las dimensiones psicológicas de la amistad que propone el autor, identificando una serie de variables y realizando un análisis mediante una encuesta a estudiantes universitarios que son usuarios activos de la plataforma. Con estos resultados se extrajo la estadística descriptiva y se realizó un análisis no paramétrico de las variables para determinar si Facebook efectivamente ofrece las condiciones necesarias para la vivencia de la verdadera amistad en sus dimensiones psicológicas. Como muestran los resultados, la experiencia de la verdadera amistad en las redes sociales es difícil, dado que la naturaleza de las interacciones entre los usuarios de la plataforma no son las adecuadas para esta experiencia. Al llamar amistad a este tipo diferente de relación, Facebook se beneficia de un atractivo gancho que lleva a los usuarios a generar contactos como moneda de cambio que favorece el modelo de negocio de la plataforma de redes sociales. El concepto de verdadera amistad se altera, deforma y desplaza a favor de otro tipo de relaciones

    Failure regime in (1+1) dimensions in fibrous materials

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    In this paper, we introduce a model for fracture in fibrous materials that takes into account the rupture height of the fibers, in contrast with previous models. Thus, we obtain the profile of the fracture and calculate its roughness, defined as the variance around the mean height. We investigate the relationship between the fracture roughness and the fracture toughness.Comment: 4 pages, 4 figures.eps, Revte

    Food preservation under pressure (hyperbaric storage) as a possible improvement/alternative to refrigeration

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    Food preservation is highly dependent on refrigeration, which is limited by its high energy costs. Among alternatives being developed, this review focused on hyperbaric storage (food preservation under pressure). This new preservation methodology has as main objective microbial growth inhibition similarly to freezing and refrigeration, showing a great potential to lower energy costs since refrigerated/room temperatures (RT) can be used. This, even at variable (uncontrolled) RT (up to 37 C), has been shown to preserve foods and thus achieving significant energy savings. Covering the earliest up to the more recent studies, this review aimed to gather information about the state of art of hyperbaric storage at refrigerated and RTs, with the primary objective of showing it potential and possible future applications of this new preservation method based on microbial growth inhibition under pressure, using pressure as the main variable to slow down microbial growth
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