2,066 research outputs found

    The volatile composition of Portuguese propolis towards its origin discrimination

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    The volatiles from thirty six propolis samples collected from six different geographical locations in Portugal (mainland, Azores archipelago and Madeira Island) were evaluated. Populus x canadensis Moenchen leaf-buds and Cistus ladanifer L. branches essential oils were comparatively analysed. The essential oils were isolated by hydrodistillation and analysed by Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS). Cluster analysis based on propolis samples volatiles chemical composition defined three main clusters, not related to sample site collection. Cluster I grouped 28 samples with high relative amounts of oxygen-containing sesquiterpenes (20-77%), while cluster II grouped 7 samples rich in oxygen-containing monoterpenes (9-65%) and the only sample from cluster III was monoterpene hydrocarbons rich (26%). Although Populus x canadensis and Cistus ladanifer were associated as resin sources of Portuguese propolis, other Populus species as well as plants like Juniperus genus may contribute to the resin in specific geographical locations.Soraia I. Falcão thanks Fundação para a Ciência e a Tecnologia (FCT) for the PhD grant SFRH/BD/44855/2008, financially supported by POPH-QREN and FSE. This study was partially funded by FCT, under Pest-OE/EQB/LA0023/2011 and PTDC/CVT-EPI/2473/2012. Thanks to National Federation of Portuguese Beekeepers for propolis samples.info:eu-repo/semantics/publishedVersio

    Foeniculum vulgare Essential Oils: Chemical Composition, Antioxidant and Antimicrobial Activities

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    The essential oils from Foeniculum vulgare commercial aerial parts and fruits were isolated by hydrodistillation, with different distillation times (30 min, I h, 2 h and 3 h), and analyzed by GC and GC-MS. The antioxidant ability was estimated using four distinct methods. Antibacterial activity was determined by the agar diffusion method. Remarkable differences, and worrying from the quality and safety point of view, were detected in the essential oils. trans-Anethole (31-36%), alpha-pinene (14-20%) and limonene (11-13%) were the main components of the essentials oil isolated from F. vulgare dried aerial parts, whereas methyl chavicol (= estragole) (79-88%) was dominant in the fruit oils. With the DPPH method the plant oils showed better antioxidant activity than the fruits oils. With the TBARS method and at higher concentrations, fennel essential oils showed a pro-oxidant activity. None of the oils showed a hydroxyl radical scavenging capacity >50%, but they showed an ability to inhibit 5-lipoxygenase. The essential oils showed a very low antimicrobial activity. In general, the essential oils isolated during 2 h were as effective, from the biological activity point of view, as those isolated during 3 h.info:eu-repo/semantics/publishedVersio

    Replacing coal-fired power plants by photovoltaics in the Portuguese electricity system

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    The decarbonization of the Portuguese electricity system, currently around 50% renewable-based, is undergoing with the commitment to reach 60% of renewable electricity share by 2020. Because of this, the phase-out of the two remaining coal-fired power plants has been receiving close attention, as they currently contribute to about one-fifth of the total electricity generation and two-thirds of the CO2 emissions in the power sector. This work assesses the impact of eliminating coal-fired generation from the Portuguese electricity system without replacing it, and explores a cleaner supply alternative achievable before 2025. Coal phase-out without substitution results in slightly increased CO2 emissions for the atmosphere if one assumes that the required additional imports are of carbon-intensive electricity, leading to the need of adding clean power capacity to the system. It is shown that coal plants could be replaced by about 8 GW of photovoltaics if accompanied by a modest increase in the already existing hydro pump capacity. In this case, the renewable electricity share increases to 77%, and carbon footprint decreases by 56%publishe

    Optimization of Photovoltaic Self-consumption using Domestic Hot Water Systems

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    Electrified domestic hot water systems, being deferrable loads, are an important demand side management tool and thus have the potential to enhance photovoltaic self-consumption. This study addresses the energy and economic performance of photovoltaic self-consumption by using a typical Portuguese dwelling. Five system configurations were simulated: a gas boiler (with/without battery) and an electric boiler (without demand management and with genetic and heuristic optimization). A sensitivity analysis on photovoltaic capacity shows the optimum photovoltaic sizing to be in the range 1.0 to 2.5 kWp. The gas boiler scenario and the heuristic scenario present the best levelized cost of energy, respectively, for the lower and higher photovoltaic capacities. The use of a battery shows the highest levelized cost of energy and the heuristic scenario shows the highest solar fraction (56.9%). Results also highlight the great potential on increasing photovoltaic size when coupled with electrified domestic hot water systems, to accommodate higher solar fractions and achieve lower costs, through energy management

    Antioxidant, Anti-5-lipoxygenase and Antiacetylcholinesterase Activities of Essential Oils and Decoction Waters of Some Aromatic Plants

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    The scavenging of free radicals and superoxide anion, the inhibition of 5-lipoxygenase and the antiacetylcholinesterase activities of essential oils and decoction waters of eight aromatic plants (Dittrichia viscosa, Foeniculum vulgare, Origanum vulgare, Salvia officinalis, Thymbra capitata, Thymus camphoratus, Thymus carnosus and Thymus mastichina) were studied. The essential oils were dominated by 1,8-cineole in S. officinalis (59%), T. mastichina (49%) and T. camphoratus (21%); borneol (20%) in T. carnosus; carvacrol in Thymbra capitata (68%); gamma-terpinene (49%) in O. vulgare; alpha-pinene (26%) in F. vulgare; and trans-nerolidol (8%) + beta-oplopenone (7%) in D. viscosa. O. vulgare decoction waters had the highest amount of phenols (45 +/- 3mg GAE/mL) while F. vulgare only had 5 +/- 0mg GAE/mL. The decoction waters showed higher radical scavenging activity than the essential oils. O. vulgare decoction water showed the best antioxidant activity (IC(50) = 3 +/- 0 mu g/mL), while the most effective essential oils were those of Thymbra capitata (IC(50) = 61 +/- 2 mu g/mL) and O. vulgare (IC(50) = 156 +/- 5 mu g/mL). Thymbra capitata (IC(50) = 6 +/- 0 mu g/mL) decoction water showed the best superoxide anion scavenging activity. F. vulgare decoction water and essential oil revealed the best 5-lipoxygenase inhibition capacity (IC(50) = 27 +/- 1 mu g/mL and IC(50) = 68 +/- 2 mu/mL, respectively). T. mastichina (IC(50) = 46 +/- 4 mu g/mL), S. officinalis (IC(50) = 51 +/- 4 mu g/mL), Thymbra capitata (IC(50) = 52 +/- 1 mu g/mL) and T. camphoratus (IC(50) = 137 +/- 2 mu g/mL) essential oils showed the best antiacetylcholinesterase activity

    Stability of Fried Olive and Sunflower Oils Enriched with Thymbra capitata Essential Oil

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    The stability of olive and sunflower oils for domestic uses after frying cow steak or only heating were evaluated in the presence or absence of the carvacrol-rich essential oil of Thymbra capitata. The treatments consisted of sunflower and olive oils either enriched with 200 mg/l of T. capitata oil or without it, heating at 180°C for 20 min, or frying 100 g cow steak at the same temperature and for the same period of time. In all assays, acid, peroxide, and p-anisidine values were followed over time. The fatty acid profile was estimated before heating or frying as well as at the end of the experiment. The results showed that the type of fat as well as the type of treatment (frying or heating) was determinant for the acid, peroxide, and p-anisidine values found. The presence of the essential oil also demonstrated to affect those values depending on the type of the oil as well as on the type of the treatment (frying or heating). In contrast, the fatty acid profile did not change greatly

    Antioxidant activity of thymbra capitata essential oil in meat-treated oil

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    Several synthetic antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and tertiary butyl hydroquinone (TBHQ), have been used to preserve meat. Nevertheless they are considered toxic and to have carcinogenic effects. Natural products, such as those present in essential oils, have been the target of studies as alternative antioxidants, showing promising results. In addition, these natural compounds have the advantage of having consumer's acceptance. Thymbra capitata is a perennial, herbaceous shrub commonly used as a spicy herb. The essential oils isolated from this plant showed antimicrobial and antioxidant activities. The main goal of the present work was to evaluate the capacity of T. capitata oil to prevent lipid oxidation in bovine meat. Different concentrations of essential oil (0, 50, 75 and 100 mg/5 g of meat) were used in two types of bovine meat samples purchased in the local market. The protein content of both types of meat samples was 21%, and lipid content ranged from 9% to 15%. After covering with the oil, the two types of meat samples were stored at -17 degrees C, for one month. After 1 day, 15 days and 30 days, meat samples were taken and cooked at 85 degrees C for 90 min. The samples were then submitted to the TBARS modified method, for antioxidant activity evaluation. The essential oil was able to prevent meat oxidation even after one month of storage and showed a dose-dependent activity

    Paternal Adjustment and Paternal Attitudes Questionnaire: Antenatal and postnatal portuguese versions

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    The Paternal Adjustment and Paternal Attitudes Questionnaire (PAPA) was designed to assess paternal adjustment and paternal attitudes during the transition to parenthood. This study aimed to examine the psychometric characteristics of the Portuguese versions of the PAPA-Antenatal (PAPA-AN) and -Postnatal (PAPA-PN) versions. A nonclinical sample of 128 fathers was recruited in the obstetrics outpatient unit, and they completed both versions of the PAPA and selfreport measures of depressive and anxiety symptoms during pregnancy and the postpartum period, respectively. Good internal consistency for both PAPA-AN and PAPA-PN was found. A three-factor model was found for both versions of the instrument. Longitudinal confirmatory factor analysis revealed a good model fit. The PAPA-AN and PAPA-PN subscales revealed good internal consistency. Significant associations were found between PAPA (PAPA-AN and PAPA-PN) and depressive and anxiety symptoms, suggesting good criterion validity. Both versions also showed good clinical validity, with optimal cutoffs found. The present study suggested that the Portuguese versions of the PAPA are reliable multidimensional self-report measures of paternal adjustment and paternal attitudes that could be used to identify fathers with adjustment problems and negative attitudes during the transition to parenthood.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research was supported by FEDER Funds through the Programa Operacional Factores de Competitividade–COMPETE and by National Funds through FCT–Fundação para a Ciência e a Tecnologia under the project PTDC/SAU/SAP/116738/2010. This research was also supported by FEDER funding from the Operational Programme Factors of Competitiveness–COMPETE and by national funding from the FCT–Foundation for Science and Technology (Portuguese Ministry of Education and Science) within the project “Health, Governance and Accountability in Embryo Research: Couples’ Decisions About the Fates of Embryos” (FCOMP-01-0124-FEDER-014453), and a PhD grant (SFRH/BD/75807/2011), cofunded by the POPH (Programa Operacional de Potencial Humano) Programme

    Rab27a targeting to melanosomes requires nucleotide exchange but not effector binding

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    Rab GTPases are important determinants of organelle identity and regulators of vesicular transport pathways. Consequently, each Rab occupies a highly specific subcellular localization. However, the precise mechanisms governing Rab targeting remain unclear. Guanine nucleotide exchange factors (GEFs), putative membrane-resident targeting factors and effector binding have all been implicated as critical regulators of Rab targeting. Here, we address these issues using Rab27a targeting to melanosomes as a model system. Rab27a regulates motility of lysosome-related organelles and secretory granules. Its effectors have been characterized extensively, and we have identified Rab3GEP as the non-redundant Rab27a GEF in melanocytes (Figueiredo AC et al. Rab3GEP is the non-redundant guanine nucleotide exchange factor for Rab27a in melanocytes. J Biol Chem 2008;283:23209-23216). Using Rab27a mutants that show impaired binding to representatives of all four Rab27a effector subgroups, we present evidence that effector binding is not essential for targeting of Rab27a to melanosomes. In contrast, we observed that knockdown of Rab3GEP resulted in mis-targeting of Rab27a, suggesting that Rab3GEP activity is required for correct targeting of Rab27a. However, the identification of Rab27a mutants that undergo efficient GDP/GTP exchange in the presence of Rab3GEP in vitro but are mis-targeted in a cellular context indicates that nucleotide loading is not the sole determinant of subcellular targeting of Rab27a. Our data support a model in which exchange activity, but not effector binding, represents one essential factor that contributes to membrane targeting of Rab proteins.publishersversionpublishe

    Phenols, essential oils and carotenoids of Rosa canina from Tunisia and their antioxidant activities

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    The antioxidant activity of leaf extracts of Rosa canina from diverse localities of Tunisia were evaluated by ABTS and DPPH methods, whereas in those of essential oils and carotenoids extracts such activity was determined only by the ABTS method. Total phenols determined by the Folin method revealed that at Aindraham, samples showed a great variability of phenol content in contrast to those from Feija. After chemical analysis of the essential oils by gas chromatography (GC) and gas chromatography coupled to mass spectra (GC-MS), revealed that the oils of Feija were predominantly composed of palmitic acid, vitispirane, linoleic acid, lauric acid, myristic acid and phytol acetate, while in those samples from Aindraham predominated vitispirane, palmitic acid, linoleic acid and phytol acetate. Higher concentrations of beta-carotene and lycopene were found in the samples from Aindraham after determination by high performance liquid chromatography (HPLC). All samples possess antioxidant activity, nevertheless much more significant in phenol extracts in contrast to the carotenoid extracts, which possess the lowest activity
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