936 research outputs found

    European lampreys: new insights on postglacial colonization, gene flow and speciation.

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    Ice ages are known to be the most dominant palaeoclimatic feature occurring on Earth, producing severe climatic oscillations and consequently shaping the distribution and the population structure of several species. Lampreys constitute excellent models to study the colonization of freshwater systems, as they commonly appear in pairs of closely related species of anadromous versus freshwater resident adults, thus having the ability to colonize new habitats, through the anadromous species, and establish freshwater resident derivates. We used 10 microsatellite loci to investigate the spatial structure, patterns of gene flow and migration routes of Lampetra populations in Europe. We sampled 11 populations including the migratory L. fluviatilis and four resident species, L. planeri, L. alavariensis, L. auremensis and L. lusitanica, the last three endemic to the Iberian Peninsula. In this southern glacial refugium almost all sampled populations represent a distinct genetic cluster, showing high levels of allopatric differentiation, reflecting long periods of isolation. As result of their more recent common ancestor, populations from northern Europe are less divergent among them, they are represented by fewer genetic clusters, and there is evidence of strong recent gene flow among populations. These previously glaciated areas from northern Europe may have been colonized from lampreys expanding out of the Iberian refugia. The pair L. fluviatilis/L. planeri is apparently at different stages of speciation in different locations, showing evidences of high reproductive isolation in the southern refugium, and low differentiation in the north

    Isothermal Variation Of The Entropy (Δ St) For The Compound Gd5 Ge4 Under Hydrostatic Pressure

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    In the present work, the isothermal variation of the entropy (Δ ST) for the compound Gd5 Ge4 was studied at different applied hydrostatic pressures (from 0 up to 0.58 GPa). In all pressure ranges, we observe the giant magnetocaloric effect. The Δ ST data for the compound Gd5 Ge4 at zero applied pressure present two peaks: the lowest temperature peak is due to irreversible processes and the highest temperature peak is due to magnetostructural transitions. Increasing the pressure, the lowest temperature peak displaces to lower temperatures and disappears. The magnitude of the other peak has a nonlinear behavior with pressure. Different protocols were used to obtain Δ ST at zero applied pressure and the results indicate that Δ ST strongly depends on the initial and final states of Gd5 Ge4 compound. We also present a T-P magnetic phase diagram built from the available magnetic data. © 2008 American Institute of Physics.1046Pecharsky, V.K., Gschneidner Jr., K.A., (1999) J. Magn. Magn. Mater., 200, p. 44. , 0304-8853 10.1016/S0304-8853(99)00397-2Tishin, A.M., Spichkin, Y.I., (2003) The Magnetocaloric Effect and Its Applications, , (IOP, Bristol)Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494. , 0031-9007 10.1103/PhysRevLett.78.4494Magen, C., Arnold, Z., Morellon, L., Skorokhod, Y., Algarabel, P.A., Ibarra, M.R., Kamarad, J., (2003) Phys. Rev. Lett., 91, p. 207202. , 0031-9007 10.1103/PhysRevLett.91.207202Levin, E.M., Gschneidner Jr., K.A., Pecharsky, V.K., (2002) Phys. Rev. B, 65, p. 214427. , 0163-1829 10.1103/PhysRevB.65.214427Levin, E.M., Pecharsky, V.K., Gschneidner Jr., K.A., Miller, G.J., (2001) Phys. Rev. B, 64, p. 235103. , 0163-1829 10.1103/PhysRevB.64.235103Tang, H., Pecharsky, V.K., Gschneidner Jr., K.A., (2004) Phys. Rev. B, 69, p. 064410. , 0163-1829 10.1103/PhysRevB.69.064410Chattopadhyay, M.K., Manekar, M.A., Pecharsky, A.O., Pecharsky, V.K., Gschneidner Jr., K.A., Moore, J., Perkins, G.K., Cohen, L.F., (2004) Phys. Rev. B, 70, p. 214421. , 0163-1829 10.1103/PhysRevB.70.214421Mudryk, Ya., Holm, A.P., Gschneidner Jr., K.A., Pecharsky, V.K., (2005) Phys. Rev. B, 72, p. 064442. , 0163-1829 10.1103/PhysRevB.72.064442Levin, E.M., Gschneidner Jr., K.A., Lograsso, T.A., Schlagel, D.L., Pecharsky, V.K., (2004) Phys. Rev. B, 69, p. 144428. , 0163-1829 10.1103/PhysRevB.69.144428Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Appl. Phys. Lett., 70, p. 3299. , 0003-6951 10.1063/1.119206Nikitin, S.A., Myalikgulyev, G., Tishin, A.M., Annaorazov, M.P., Asatryan, K.A., Tyurin, A.L., (1990) Phys. Lett. A, 148, p. 363. , 0375-9601 10.1016/0375-9601(90)90819-APecharsky, V.K., Gschneidner Jr., K.A., (1999) J. Appl. Phys., 86, p. 565. , 0021-8979 10.1063/1.370767Carvalho, A.M.G., (2006), Ph.D. thesis, UNICAMPCarvalho, A.M.G., Alves, C.S., De Campos, A., Coelho, A.A., Gama, S., Gandra, F.C.G., Von Ranke, P.J., De Oliveira, N.A., (2005) J. Appl. Phys., 97, pp. 10M320. , 0021-8979 10.1063/1.1860932Gschneidner Jr., K.A., Pecharsky, V.K., (2000) Annu. Rev. Mater. Sci., 30, p. 387. , 0084-6600 10.1146/annurev.matsci.30.1.387Carvalho, A.M.G., Alves, C.S., Colucci, C.C., Bolanho, M.A., Coelho, A.A., Gama, S., Nascimento, F.C., Cardoso, L.P., (2007) J. Alloys Compd., 432, p. 11. , 0925-8388 10.1016/j.jallcom.2006.05.121Wood, M.E., Potter, W.H., (1985) Cryogenics, 25, p. 667. , 0011-2275 10.1016/0011-2275(85)90187-0Magnus, A., Carvalho, G., Coelho, A.A., Gama, S., Von Ranke, P.J., De Oliveira, N.A., Da Silva, L.M., Gandra, F.C.G., (submitted

    Ti6Al4V-PEEK multi-material structures – design, fabrication and tribological characterization focused on orthopedic implants

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    Acknowledgements: This work was supported by FCT through the grants SFRH/BD/128657/2017 and SFRH/BPD/112111/2015, the project PTDC/EMSTEC/5422/2014 and also by project NORTE 01-0145_FEDER-000018. Additionally, this work was supported by FCT with the reference project UID/EEA/04436/2013, by FEDER funds through the COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI) with the reference project POCI-01-0145-FEDER-006941.A multi-material concept that gathers Ti6Al4V and PEEK properties in a cellular structured component was designed, fabricated and investigated targeting hip implants. SLM and pressure assisted injection techniques were used to obtain Ti6Al4V-PEEK multi-material structures. Aiming to reproduce to some extension the tribological phenomena occurring during and after hip implant insertion, five tribological tests were outlined and performed. The obtained results showed that the presence of PEEK on the Ti6Al4V-PEEK cellular structures led to a substantial improvement on the wear resistance (62% reduction in the mass loss) when compared to the material currently available on market for hip implants. The multi-material solution here investigated shows a good compromise between the primary stability after implant insertion and the wear performance.info:eu-repo/semantics/publishedVersio

    CHO genome mining for synthetic promoter design

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    Synthetic promoters are an attractive alternative for use in mammalian hosts such as CHO cells as they can be designed de novo with user-defined functionalities. In this study, we describe and validate a method for bioprocess-directed design of synthetic promoters utilizing CHO genomic sequence information. We designed promoters with two objective features, (i) constitutive high-level recombinant gene transcription, and (ii) upregulated transcription under mild hypothermia or late-stage culture. CHO genes varying in transcriptional activity were selected based on a comparative analysis of RNA-Seq transcript levels in normal and biphasic cultures in combination with estimates of mRNA half-life from published genome scale datasets. Discrete transcription factor regulatory elements (TFREs) upstream of these genes were informatically identified and functionally screened in vitro to identify a subset of TFREs with the potential to support high activity recombinant gene transcription during biphasic cell culture processes. Two libraries of heterotypic synthetic promoters with varying TFRE combinations were then designed in silico that exhibited a maximal 2.5-fold increase in transcriptional strength over the CMV-IE promoter after transient transfection into host CHO-K1 cells. A subset of synthetic promoters was then used to create stable transfectant pools using CHO-K1 cells under glutamine synthetase selection. Whilst not achieving the maximal 2.5-fold increase in productivity over stable pools harboring the CMV promoter, all stably transfected cells utilizing synthetic promoters exhibited increased reporter production - up to 1.6-fold that of cells employing CMV, both in the presence or absence of intron A immediately downstream of the promoter. The increased productivity of stably transfected cells harboring synthetic promoters was maintained during fed-batch culture, with or without a transition to mild hypothermia at the onset of stationary phase. Our data exemplify that it is important to consider both host cell and intended bioprocess contexts as design criteria in the de novo construction of synthetic genetic parts for mammalian cell engineering

    Phenolic compounds profile, nutritional compounds and bioactive properties of Lycium barbarum L.: A comparative study with stems and fruits

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    The increasing awareness of the possible health benefits of berry fruits (Lycium barbarum L.) has led to a higher consumption of this type of food products. One of the many examples are the fruits from Lycium genus, traditionally used due to their beneficial properties and health benefits associated with liver, kidney, eyesight, immune system, circulation and longevity disorders. In the present study fruits and stems of Lycium barbarum L. (goji) were characterized in terms of nutritional profile, sugars, organic acids, fatty acids and tocopherols. Furthermore, a phenolic characterization of their hydromethanolic extracts was performed and correlated with bioactive properties such as antioxidant, hepatotoxic and antibacterial activities. Stems presented higher values of energy, MUFA (monounsaturated fatty acids), tocopherols and flavonols. Stems also showed greater antioxidant and antibacterial (against Gram-negative bacteria) activities. Otherwise, fruits revealed higher contents of sugars, PUFA (polyunsaturated fatty acids) and hydroxycinnamic acid derivatives, and greater activity against Gram-positive bacteria. This is an innovative study that shows the high potential of goji stems and fruits as sources of bioactive compounds, which could be used in nutraceutical formulations, or incorporated into food products with functional properties. Furthermore, the use of stems could bring industrial sustainability as a valuable by-product, which has been scarcely reported.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013), T.C.S.P. Pires (SFRH/BD/129551/2017) grant and L. Barros contract. The GIP-USAL is financially supported by the Spanish Government through the project AGL2015-64522-C2-2-R. The authors are grateful to FEDER-Interreg España-Portugal programme for financial support through the project 0377_Iberphenol_6_E.info:eu-repo/semantics/publishedVersio

    Development of new bilberry (Vaccinium myrtillus L.) based snacks: Nutritional, chemical and bioactive features

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    The sustainable exploitation of fruit and cereal processing is being conducted to produce novel food products with promising nutritional properties and high content in added value compounds. Herein, three bilberry fruit-based snacks supplemented with edible petals and fruits were characterized for their nutritional properties and chemical composition. The phenolic profile, antioxidant, antibacterial and hepatotoxic properties were analyzed. Protein (3–4 g/100 g dw) and carbohydrates (94.3–94.8 g/100 g dw) represented the major macronutrients. The combination of bilberry fruits with edible petals, calendula and rose, improved the nutritional and phytochemical input in organic acids and tocopherols content, respectively. Also, the supplementation with apple and goji fruits provided higher content in phenolic acids and anthocyanins (up to a 9-fold higher concentration, 199.7 µg/g of extract), also resulting in a higher antioxidant and antibacterial activities. The results obtained can contribute for the development of novel sustainable and healthier snacks for the food industry.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES to CIMO (UIDB/00690/2020); national funding by FCT, P.I., through the institutional scientific employment programcontract for M.I. Dias, R.C. Calhelha and L. Barros contracts; individual PhD fellowship for Tânia Pires (SFRH/BD/129551/2017); to the European Structural and Investment Funds (FEEI) through the Regional Operational Program North 2020, within the scope of project Mobilizador ValorNatural®; and to FEDER-Interreg España-Portugal programme for financial support through the project 0377_Iberphenol_6_E and TRANSCoLAB 0612_TRANS_CO_LAB_2_P. The GIP-USAL is financially supported by the Spanish Government through the project AGL2015-64522-C2-2-R.info:eu-repo/semantics/publishedVersio

    Influence of compacting pressure on the magnetic and structural properties in Gd5Ge2.15Si1.85 alloy obtained by powder metallurgy

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    The magnetocaloric effect (MCE) has been studied seeking their application in cooling systems near room temperature (domestic employ). The magnetic refrigerators work with nontoxic solids that substitute the refrigerant gases used in hermetic compressors, without relying on ozone-depleting coolants. Some alloys of Gd5(Ge xSi4-x) present the giant magnetocaloric effect (GMCE), and the Gd5Ge2Si2 alloy, announced in 1997 by Pecharsky e Gschneidner, have a first-order magneto-structural transition at the Curie Temperature (Tc = 273 K) and MCE around 30 J.(kg.K)-1, being probable their use in those cooling systems. However, when that material is sintered, it loses its initial characteristics during the powder metallurgy process. Therefore, this study will treat of the compacting pressure interferences on the structural and magnetic properties of the Gd5Ge2.15Si1.85 alloy.O denominado efeito magnetocalórico (EMC) vem sendo estudado visando sua aplicação em sistemas de refrigeração próximas à temperatura ambiente (uso doméstico). Os refrigeradores magnéticos operam com base em sólidos atóxicos que substituem os gases refrigerantes usados em compressores herméticos, como os CFC?s e HCFC?s, altamente poluentes. Algumas ligas da família Gd5(Ge xSi4-x) apresentam o efeito magnetocalórico gigante (EMCG), sendo que a liga Gd5Ge2Si2, apresentada em 1997 por Pecharsky e Gschneidner, possui transição magneto-estrutural de primeira ordem na temperatura de Curie (Tc = 273 K) e EMC por volta de 30 J.(kg.K)-1, sendo provável o seu uso nesses sistemas de refrigeração. Entretanto, quando submetida a uma pressão de compactação e posterior sinterização, o material perde suas características iniciais. Assim sendo, este estudo tratará da influência da pressão de compactação sobre as propriedades estruturais e magnéticas na liga de Gd5Ge2,15Si1,85.12512

    Edible flowers as sources of phenolic compounds with bioactive potential

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    The edible flowers are widely used, but there is still a lot to be done in relation to its bioactive potential and its correlation with the presence of phenolic compounds. The aim of this study was determined the individual phenolic profile in the hydromethanolic extracts and infusion preparations of four different flower samples (Dahlia mignon, Rosa damascena ‘Alexandria’ and R. gallica ‘Francesa’ draft in R. canina, Calendula officinalis L., and Centaurea cyanus L.) and their bioactive potential (antioxidant, antiproliferative, and antibacterial capacity). All the studied flowers presented different profiles regarding their phenolic composition and revealed biological potential. The bioactive potential of the studied flowers was moderate, the hydromethanolic extracts of rose petals showed the best results for antioxidant and antibacterial assays, while the antiproliferative properties were only present in some of the tested cell lines, for the hydromethanolic extracts, in which dahlia and rose showed the best results. These results demonstrate that edible flowers can be used as a source of phenolic compounds with bioactive potential, which can be applied in the food sector, as foods and as sources natural ingredients.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013), T.C.S.P. Pires (SFRH/BD/129551/2017) grant, L. Barros contract and to the Interreg España-Portugal for financial support through the project 0377_Iberphenol_6_E. The authors are also grateful to Prof. Carlos Aguiar (CIMO) for systematic identification of the studied species.info:eu-repo/semantics/publishedVersio
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