On the consistent solution of the gap--equation for spontaneously broken λΦ4\lambda \Phi^4-theory

We present a self--consistent solution of the finite temperature gap--equation for $\lambda \Phi^4$ theory beyond the Hartree-Fock approximation using a composite operator effective action. We find that in a spontaneously broken theory not only the so--called daisy and superdaisy graphs contribute to the resummed mass, but also resummed non--local diagrams are of the same order, thus altering the effective mass for small values of the latter.Comment: 15 pages of revtex + 3 uuencoded postscript figures, ENSLAPP A-488/9

Semiclassical thermodynamics of scalar fields

We present a systematic semiclassical procedure to compute the partition function for scalar field theories at finite temperature. The central objects in our scheme are the solutions of the classical equations of motion in imaginary time, with spatially independent boundary conditions. Field fluctuations -- both field deviations around these classical solutions, and fluctuations of the boundary value of the fields -- are resummed in a Gaussian approximation. In our final expression for the partition function, this resummation is reduced to solving certain ordinary differential equations. Moreover, we show that it is renormalizable with the usual 1-loop counterterms.Comment: 24 pages, 5 postscript figure

Flores e frutos imaturos de Crataegus monogyna revelam elevado potencial antioxidante.

A espécie Crataegus monogyna, conhecida vulgarmente como espinheiro, escaramunheiro ou pilriteiro, está entre as plantas do Nordeste de Portugal mais recomendadas pela medicina tradicional. As suas bagas são comumente consumidas por serem consideradas nutritivas e saudáveis, podendo também ser utilizadas como suplemento alimentar, sobretudo para crianças, devido ao seu elevado conteúdo vitamínico [1]. O espinheiro é reconhecido como tendo propriedades bioativas de interesse elevado, em particular na prevenção de doenças cardiovasculares e gastrointestinais. De forma a compreender melhor o potencial terapêutico do espinheiro, a atividade antioxidante de diferentes partes da planta (botões e brácteas florais, flores e frutos) foi avaliada através de diferentes métodos químicos e bioquímicos. Os extratos etanólicos demonstraram maior potencial antioxidante que os extratos aquosos, mas os resultados foram muito satisfatórios em ambos os casos, revelando o potencial do espinheiro para ser incluído em formulações terapêuticas ou produtos dietéticos de referência

Qualidade nutricional de agrião armazenado em atmosferas modificadas enriquecidas em gás inerte

O agrião (Nasturtium offidnale R. Br. ) é uma planta de crescimento rápido da família Brassicaceae consumida em sopas e saladas. Contudo, tal como a maioria dos vegetais, é altamente perecível. A utilização de embalagens com atmosfera modificada ou protetora tem aumentado nos últimos anos dado o seu potencial para prolongar a vida útil de vegetais minimamente processados. Esta técnica consiste em alterar a atmosfera dentro da embalagem, com o objetivo de abrandar o metabolismo e de prevenir reações de oxidação, evitando assim alterações de qualidade associadas a processos de maturação e senescência. A utilização de gases inertes tem sido testada, mas os estudos são ainda muito limitados. Neste sentido, este trabalho teve como objetivo avaliar os efeitos induzidos por diferentes atmosferas na qualidade nutricional de agrião minimamente processado durante o armazenamento refrigerado e selecionar o tratamento mais eficaz na extensão da vida útil. Amostras silvestres de agrião, recolhidas na região de Bragança, foram lavadas em água corrente e uma porção imediatamente analisada (controlo não armazenado). O restante material fresco foi embalado em atmosferas enriquecidas em azoto, árgon e ar (atmosfera controlo passiva), armazenado a 4°C durante 7 dias e posteriormente analisado. Determinou-se o teor em água, proteínas, lípides, glúcidos e cinzas e o valor energético seguindo métodos oficiais de análise; os perfis em açúcares, ácidos orgânicos, tocoferóis e ácidos gordos foram analisados por técnicas cromatográficas; e as propriedades antioxidantes avaliadas por ensaios químicos e bioquímicos. Tendo em conta a contribuição de todos os parâmetros de qualidade avaliados, foi possível concluir que o embatamento passivo foi o menos eficiente em preservar os atributos de qualidade característicos das amostras controlo não armazenadas. Por outro lado, o embalamento em atmosfera enriquecida em árgon foi a escolha mais acertada para preservar a qualidade global das amostras. Adicionalmente, este estudo destacou as propriedades nutricionais e antioxidantes do agrião, realçando assim o interesse da sua reinclusão nas dietas atuais

Targeting excessive free radicals with peels and juices of citrus fruits: grapefruit, lemon, lime and orange

A comparative study between the antioxidant properties of peel (flavedo and albedo) and juice of some commercially grown citrus fruit (Rutaceae), grapefruit (Citrus paradisi), lemon (Citrus limon), lime (Citrus aurantiifolia) and sweet orange (Citrus sinensis) was performed. Different in vitro assays were applied to the volatile and polar fractions of peels and to crude and polar fraction of juices: 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, reducing power and inhibition of lipid peroxidation using b-carotene–linoleate model system in liposomes and thiobarbituric acid reactive substances (TBARS) assay in brain homogenates. Reducing sugars and phenolics were the main antioxidant compounds found in all the extracts. Peels polar fractions revealed the highest contents in phenolics, flavonoids, ascorbic acid, carotenoids and reducing sugars, which certainly contribute to the highest antioxidant potential found in these fractions. Peels volatile fractions were clearly separated using discriminant analysis, which is in agreement with their lowest antioxidant potential

Electron beam and gamma irradiation as feasible conservation technologies for wild Arenaria montana L.: effects on chemical and antioxidant parameters

Wild plants are widely recognized as high-potential sources of several bioactive compounds. Nevertheless, these natural matrices require effective decontamination steps before they might be considered for different industrial purposes. Irradiation techniques are being progressively acknowledged as feasible conservation methodologies, either for their high decontamination effectiveness, as well as for their innocuousness on most chemical and bioactive parameters of the material to be treated. Arenaria montana L. (Caryophyllaceae) is recognized for its phytochemical richness, having a relevant geographical distribution in the Southern Europe. Herein the effects of irradiation (gamma and electron beam up to 10 kGy) were evaluated by comparing the nutritional, chemical and antioxidant profiles in A. montana extracts. In general, the assayed parameters showed statistically significant variations in response to irradiation treatment. Furthermore, the performed LDA allowed identifying the antioxidant indicators as the most affected parameters in irradiated samples, especially when using the 10 kGy dose and e-beam irradiation.Ministry of Agriculture, Portugal (Project PRODER/FEADER/EU no. 53514), for financial support of the work and E. Pereira grant; Foundation for Science and Technology (FCT, Portugal) for financial support to CIMO (PEst-OE/AGR/UI0690/2014), CTN (RECI/AAG-TEC/0400/2012), L. Barros (BPD/107855/2015) and J.C.M. Barreira (BPD/72802/2010). And to Prof A. Chmielewski, Director of INCT, and Dr A. Rafalski, for e-beam irradiations

Propensity for biofilm formation by clinical isolates from urinary tract infections: developing a multifactorial predictive model to improve the antibiotherapy

A group of biofilm-producing bacteria isolated from patients with urinary tract infections was evaluated, identifying the main factors contributing to biofilm formation. Among the 156 isolates, 58 (37.2%) were biofilm producers. The bacterial species (P<0.001), together with patient's gender (P = 0.022), were the factors with the highest influence for biofilm production. There was also a strong correlation of catheterization with biofilm formation, despite being less significant (P = 0.070) than species or gender. In fact, some of the bacteria isolated were biofilm producers in all cases. With regard to resistance profile among bacterial isolates, β-lactam antibiotics presented the highest number of cases/percentages--ampicillin (32/55.2%), cephalothin (30/51.7%), amoxicillin/clavulanic acid (22/37.9%)--although the carbapenem group still represented a good therapeutic option (2/3.4%). Quinolones (nucleic acid synthesis inhibitors) also showed high resistance percentages. Furthermore, biofilm production clearly increases bacterial resistance. Almost half of the biofilm-producing bacteria showed resistance against at least three different groups of antibiotics. Bacterial resistance is often associated with catheterization. Accordingly, intrinsic (age and gender) and extrinsic (hospital unit, bacterial isolate and catheterization) factors were used to build a predictive model, by evaluating the contribution of each factor to biofilm production. In this way, it is possible to anticipate biofilm occurrence immediately after bacterial identification, allowing selection of a more effective antibiotic (among the susceptibility options suggested by the antibiogram) against biofilm-producing bacteria. This approach reduces the putative bacterial resistance during treatment, and the consequent need to adjust antibiotherapy.Fundação para a Ciência e a Tecnologia (FCT, Portugal) and COMPETE/QREN/EU for financial support to this work (strategic projects PEst-OE/AGR/UI0690/2011 and PEst-OE/EQB/LA0016/2011). They also thank to CHTMAD – Hospital Center of Trás-os-Montes e Alto Douro and Siemens for all the support. J.C.M. Barreira also thanks to FCT, POPH-QREN and FSE for his grant (SFRH/BPD/72802/2010

Perennial spotted rockrose as a source of Ellagitannins with therapeutic interest: influence of drying and extraction conditions

The ellagitannins are a diverse class of hydrolysable tannins, a type of polyphenols present in some fruits, medicinal plants, nuts and seeds. They are complex derivatives of ellagic acid characterized by one or more hexahydroxydiphenoyl moieties esterified to a sugar, usually glucose [1]. These compounds play an important role in human nutrition and are endowed with numerous biological properties, including antioxidant, anti-inflammatory, anticancer, antiatherosclerotic, antihepatotoxic, antibacterial and anti-HIV replication activities [1-3], being therefore interesting molecules for medicinal and therapeutic applications. A previous work of our research team highlighted the perennial spotted rockrose (Tuberaria lignosa (Sweet) Samp.) as a rich source of ellagitannins, namely punicalagin [2]. In this study, the influence of drying and extraction conditions on the ellagitannins content from perennial spotted rockrose flowering aerial parts was evaluated. Wild specimens were gathered in the Northeast region of Portugal and then freeze-dried immediately after gathering or shade-dried in a dark and dry place at room temperature for 30 days. Subsequently, dried samples were extracted adding them to boiling water and left to stand at room temperature for 5 min, or boiling them for 5 min plus 5 min at room temperature. The ellagitannins analysis was performed by HPLC-DAD-ESI/MS. The effects of drying and extraction conditions were evaluated by analysis of variance (ANOVA) using the General Linear Model procedure. The most abundant ellagitannins were punicalagin isomers and punicalagin gallate isomers, being the highest levels detected in freeze-dried samples. Additionally, higher amounts of these compounds were achieved with longer extraction time (5 min + 5 min), in both shade- and freeze-dried samples. Thus, from the obtained results, it might be concluded that freeze-drying and longer extraction time are the preferable conditions to obtain high levels of ellagitannins with therapeutic interest from perennial spotted rockrose samples

Evaluation of growth inhibitory activity of Crataegus monogyna Jacq. flower bud extracts against human tumor cell lines

The vast structural diversity of natural compounds found in plants provides unique opportunities for discovering new drugs with possible beneficial effects on human health, including regulation of proliferation and cell death pathways leading to cancer [1]. Crataegus monogyna Jacq. has been studied by our research group to confirm its different alleged health benefits [2-4]. Herein, the antiproliferative activity of phenolic extracts from C. monogyna flower buds was evaluated on four different human tumor cell lines: HeLa, cervical carcinoma; HepG2, hepatocellular carcinoma; MCF-7, breast adenocarcinoma; NCI-H460, non-small cell lung cancer. The antiproliferative activity was measured by calculating Gl50 values (50% of cell growth inhibition) for each cell line, according to the procedure adopted by the National Cancer Institute for in vitro anticancer drug screening, which uses sulforhodamine B assay to assess cell groW1h inhibition [5]. The obtained antiproliferative activity was very similar among the assayed cell lines: HeLa, Gl50 = 63.55±3.56 μg/ml; HepG2, Gl50 = 88.45±8.11 μg/ml; MCF7, Gl50 = 66.96±0.01 μg/ml ; NCI -H460, Gl50 = 67.61±4.29 μg/ml. The lower activity against HepG2 cells might be related with the type of proliferation of this cell line, the only one with a monolayer growth type among the assayed lines . The activity demonstrated by the phenolic extract of C. monogyna might be explained by their high amounts in flavonoids, which are known for modulating a variety of biological events associated with cancer progression and development, such as cell proliferation, apoptosis, cell differentiation and neovascularization [3]. Accordingly, C. monogyna may be considered as a source of important phytochemicals with bioactive properties to be explored for pharmaceutical applications