3,926 research outputs found

    Effect of maturity and harvest season on antioxidant activity, phenolic compounds and ascorbic acid of Morinda citrifolia L. (noni) grown in Mexico (with track change)

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    Antioxidant activity diphenylpicrylhydrazyl (DPPH), the ferric-reducing antioxidant power assay (FRAP), nitric oxide (NO)], total polyphenols, phenolic compounds and ascorbic acid of Morinda citrifolia L. fruits were investigated as a function of maturity and three seasons patterns in Mexico. Maturity was evaluated in early, middle, sub-mature and mature stages (1 to 4) according to color and firmness. Significant differences were observed in the antioxidant activities and chemical composition of the fruits at different maturity and seasons. During February-March and May- June, fruits from middle and mature stages exhibited the highest antioxidant activities and total polyphenol content compared to other stages, while in November, ripe fruits reached the greatest antioxidant efficacy, total phenolic and ascorbic acid contents. Total polyphenols and ascorbic acid reached the highest amounts during May-June, although antioxidant activities were moderate compared to greater values in February-March or November depending upon maturity. The ability of M. citrifolia fruits to inhibit NO production by LPSactivated RAW 264.7 cells was quite comparable to or higher than N-nitro-L-arginine methyl ester (LNAME). This work shows that season and maturity stages have a profound effect on the antioxidant capacity, phenols and ascorbic acid of M. Citrifolia fruits.Keywords: Morinda citrifolia, diphenylpicrylhydrazyl (DPPH) radical scavenging, maturity, seasons, total polyphenol and phenolics compounds, reducing power, ascorbic acid, scavenging nitric oxide.African Journal of Biotechnology Vol. 12(29), pp. 4630-463

    Computational methodology to determine fluid related parameters on non regular three-dimensional scaffolds

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    The application of three-dimensional (3D) biomaterials to facilitate the adhesion, proliferation, and differentiation of cells has been widely studied for tissue engineering purposes. The fabrication methods used to improve the mechanical response of the scaffold produce complex and non regular structures. Apart from the mechanical aspect, the fluid behavior in the inner part of the scaffold should also be considered. Parameters such as permeability (k) or wall shear stress (WSS) are important aspects in the provision of nutrients, the removal of metabolic waste products or the mechanically-induced differentiation of cells attached in the trabecular network of the scaffolds. Experimental measurements of these parameters are not available in all labs. However, fluid parameters should be known prior to other types of experiments. The present work compares an experimental study with a computational fluid dynamics (CFD) methodology to determine the related fluid parameters (k and WSS) of complex non regular poly(L-lactic acid) scaffolds based only on the treatment of microphotographic images obtained with a microCT (lCT). The CFD analysis shows similar tendencies and results with low relative difference compared to those of the experimental study, for high flow rates. For low flow rates the accuracy of this prediction reduces. The correlation between the computational and experimental results validates the robustness of the proposed methodology.The authors gratefully acknowledge research support from the Spanish Ministry of Science and Innovation through research project DPI2010-20399-C04-01. The Instituto de Salud Carlos III (ISCIII) through the CIBER initiative and the Platform for Biological Tissue Characterization of the Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN) are also gratefully acknowledged.Acosta Santamaría, VA.; Malvé, M.; Duizabo, A.; Mena Tobar, A.; Gallego Ferrer, G.; García Aznar, J.; Doblare Castellano, M.... (2013). Computational methodology to determine fluid related parameters on non regular three-dimensional scaffolds. Annals of Biomedical Engineering. 41(11):2367-2380. https://doi.org/10.1007/s10439-013-0849-8S236723804111Acosta Santamaría, V., H. Deplaine, D. Mariggió, A. R. Villanueva-Molines, J. M. García-Aznar, J. L. Gómez Ribelles, M. Doblaré, G. Gallego Ferrer, and I. Ochoa. Influence of the macro and micro-porous structure on the mechanical behavior of poly(l-lactic acid) scaffolds. J. Non-Cryst. Solids 358(23):3141–3149, 2012.Adachi, T., Y. Osako, M. Tanaka, M. Hojo, and S. J. Hollister. Framework for optimal design of porous scaffold microstructure by computational simulation of bone regeneration. Biomaterials 27(21):3964–3972, 2006.Adamczyk, Z., and T. G. M. Vandeven. Deposition of particles under external forces in laminar-flow through parallel-plate and cylindrical channels. J. Colloid Interface Sci. 80(2):340–356, 1981.Alberich, B. A., D. Moratal, J. L. Escobar, J. C. Rodríguez, A. Vallés-Lluch, L. Martí-Bonmatí, et al. Microcomputed tomography and microfinite element modeling for evaluating polymer scaffolds architecture and their mechanical properties. J. Biomed. Mater. Res. B Appl. Biomater. 91B(1):191–202, 2009.Al-Munajjed, A., M. Hien, R. Kujat, J. P. Gleeson, and J. Hammer. Influence of pore size on tensile strength, permeability and porosity of hyaluronan-collagen scaffolds. J. Mater. Sci. Mater. Med. 19(8):2859–2864, 2008.Alves da Silva, M. L., A. Martins, A. R. Costa-Pinto, V. M. Correlo, P. Sol, M. Bhattacharya, S. Faria, R. L. Reis, and N. M. Neves. Chondrogenic differentiation of human bone marrow mesenchymal stem cells in chitosan-based scaffolds using a flow-perfusion bioreactor. J. Tissue Eng. Regen. Med. 5(9):722–732, 2011.Ansys (2010) CFX Theory User Manual. Canonsburg, PA: Ansys Software.Brígido, R. D., J. M. Estellés, J. A. Sanz, J. M. García-Aznar, and M. S. Sánchez. Polymer scaffolds with interconnected spherical pores and controlled architecture for tissue engineering: fabrication, mechanical properties, and finite element modeling. J. Biomed. Mater. Res. B Appl. Biomater. 81B(2):448–455, 2007.Byrne, P. D., D. Lacroix, J. A. Planell, D. J. Kelly, and P. J. Prendergast. Simulation of tissue differentiation in a scaffold as a function of porosity, Young’s modulus and dissolution rate: application of mechanobiological models in tissue engineering. Biomaterials 28:5544–5554, 2007.Chor, M. V., and W. Li. A permeability measurement system for tissue engineering scaffolds. Meas. Sci. Technol. 18(1):208–216, 2007.Cozensroberts, C., J. A. Quinn, and D. A. Lauffenburger. Receptor-mediated adhesion phenomena—model studies with the radial-flow detachment assay. Biophys. J. 58(1):107–125, 1990.Davisson, T., R. L. Sah, and A. Ratcliffe. Perfusion increases cell content and matrix synthesis in chondrocyte three-dimensional cultures. Tissue Eng. 8(5):807–816, 2002.Deplaine, H., M. Lebourg, P. Ripalda, A. Vidaurre, P. Sanz-Ramos, G. Mora, F. Prósper, I. Ochoa, M. Doblaré, J. L. Gómez Ribelles, I. Izal-Azcárate, and G. Gallego Ferrer. Biomimetic hydroxyapatite coating on pore walls improves osteointegration of poly(l-lactic acid) scaffolds. J. Biomed. Mater. Res. B Appl. Biomater. 101(1):173–186, 2013.Dias, M. R., P. R. Fernandes, J. M. Guedes, and S. J. Hollister. Permeability analysis of scaffolds for bone tissue engineering. J. Biomech. 45(6):938–944, 2012.Freyman, T. M., I. V. Yannas, and L. J. Gibson. Cellular materials as porous scaffolds for tissue engineering. Prog. Mater Sci. 46:273–282, 2001.Gong, S., H. Wang, Q. Sun, S. T. Xue, and J. Wang. Mechanical properties and in vitro biocompatibility of porous zein scaffolds. Biomaterials 27(20):3793–3799, 2006.Gutierrez, R. A., and E. T. Crumpler. Potential effect of geometry on wall shear stress distribution across scaffold surfaces. Ann. Biomed. Eng. 36(1):77–85, 2008.Hammer, D. A., and D. Lauffenburger. A dynamic-model for receptor-mediated cell adhesion to surfaces. Biophys. J. 52(3):475–487, 1987.Ho, S. T., and D. W. Hutmacher. A comparison of micro CT with other techniques used in the characterization of scaffolds. Biomaterials 27(8):1362–1376, 2006.Ho, M. H., P. Y. Kuo, H. J. Hsieh, T. Y. Hsien, L. T. Hou, J. Y. Lai, and D. M. Wang. Preparation of porous scaffolds by using freeze-extraction and freeze-gelation methods. Biomaterials 25(1):129–138, 2004.Hutmacher, D. W., J. T. Schantz, C. X. Lam, K. C. Tan, and T. C. Lim. State of the art and future directions of scaffold-based bone engineering from a biomaterials perspective. J. Tissue Eng. Regen. Med. 1(4):245–260, 2007.Izal, I., P. Aranda, P. Sanz-Ramos, P. Ripalda, G. Mora, F. Granero-Moltó, H. Deplaine, J. L. Gómez-Ribelles, G. G. Ferrer, V. Acosta, I. Ochoa, J. M. García-Aznar, E. J. Andreu, M. Monleón-Pradas, M. Doblaré, and F. Prósper. Culture of human bone marrow-derived mesenchymal stem cells on of poly(l-lactic acid) scaffolds: potential application for the tissue engineering of cartilage. Knee Surg. Sports Traumatol. Arthrosc., 2012.Kapur, S., D. J. Baylink, and K. H. Lau. Fluid flow shear stress stimulates human osteoblast proliferation and differentiation through multiple interacting and competing signal transduction pathways. Bone 32(3):241–251, 2003.Karande, T. S., J. L. Ong, and C. M. Agrawal. Diffusion in musculoskeletal tissue engineering scaffolds: design issues related to porosity, permeability, architecture, and nutrient mixing. Ann. Biomed. Eng. 32(12):1728–1743, 2004.Kelly, D. J., and P. J. Prendergast. Mechano-regulation of stem cell differentiation and tissue regeneration in osteochondral defects. J. Biomech. 38(7):1413–1422, 2005.Kreke, M. R., L. A. Sharp, Y. W. Lee, and A. S. Goldstein. Effect of intermittent shear stress on mechanotransductive signaling and osteoblastic differentiation of bone marrow stromal cells. Tissue Eng. Part A 14(4):529–537, 2008.Lacroix, D., A. Chateau, M. P. Ginebra, and J. A. Planell. Micro-finite element models of bone tissue-engineering scaffolds. Biomaterials 27(30):5326–5334, 2006.Lacroix, D., and P. J. Prendergast. A mechano-regulation model for tissue differentiation during fracture healing: analysis of gap size and loading. J. Biomech. 35(9):1163–1171, 2002.Li, S., J. R. De Wijn, J. Li, P. Layrolle, and K. De Groot. Macroporous biphasic calcium phosphate scaffold with high permeability/porosity ratio. Tissue Eng. 9:535–548, 2003.Melchels, F. P. W., B. Tonnarelli, A. L. Olivares, I. Martin, D. Lacroix, J. Feijen, et al. The influence of the scaffold design on the distribution of adhering cells after perfusion cell seeding. Biomaterials 32(11):2878–2884, 2011.O’Brien, F. J., B. A. Harley, M. A. Waller, I. Yannas, L. J. Gibson, and P. Prendergast. The effect of pore size on permeability and cell attachment in collagen scaffolds for tissue engineering. Technol. Health Care 15(1):3–17, 2007.Ochoa, I., J. A. Sanz, J. M. Garcia-Aznar, M. Doblare, D. M. Yunos, and A. R. Boccaccini. Permeability evaluation of 45S5 bioglass-based scaffolds for bone tissue engineering. J. Biomech. 42:257–260, 2009.Porter, B., R. Zauel, H. Stockman, R. Guldberg, and D. Fyhrie. 3-D computational modeling of media flow through scaffolds in a perfusion bioreactor. Mater. Res. 38:543–549, 2005.Sandino, C., S. Checa, P. J. Prendergast, and D. Lacroix. Simulation of angiogenesis and cell differentiation in a CaP scaffold subjected to compressive strains using a lattice modeling approach. Biomaterials 31(8):2446–2452, 2010.Sanz, J. A., J. M. García-Aznar, and M. Doblaré. On scaffold designing for bone regeneration: a computational multiscale approach. Acta Biomater. 5(1):219–229, 2009.Sanz, J. A., C. Kasper, M. van Griensven, J. M. Garcia-Aznar, I. Ochoa, and M. Doblare. Mechanical and flow characterization of Sponceram® carriers: evaluation by homogenization theory and experimental validation. J. Biomed. Mater. Res. B Appl. Biomater. 87B(1):42–48, 2008.Singh, H., S. H. Teoh, H. T. Low, and D. W. Hutmacher. Flow modelling within a scaffold under the influence of uni-axial and bi-axial bioreactor rotation. J. Biotechnol. 119:181–196, 2005.Sjollema, J., and H. J. Busscher. Deposition of polystyrene latex-particles toward polymethylmethacrylate in a parallel plate flow cell. J. Colloid Interface Sci. 132(2):382–394, 1989.Truscello, S., G. Kerckhofs, S. Van Bael, G. Pyka, J. Schrooten, and H. Van Oosterwyck. Prediction of permeability of regular scaffolds for skeletal tissue engineering: a combined computational and experimental study. Acta Biomater. 8(4):1648–1658, 2012.Woodfield, T. B., J. Malda, J. Wijn, F. Péters, J. Riesle, and C. A. van Blitterswijk. Design of porous scaffolds for cartilage tissue engineering using a three-dimensional fiber-deposition technique. Biomaterials 25(18):4149–4161, 2004

    TRY plant trait database - enhanced coverage and open access

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    Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

    Dilepton mass spectra in p+p collisions at sqrt(s)= 200 GeV and the contribution from open charm

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    The PHENIX experiement has measured the electron-positron pair mass spectrum from 0 to 8 GeV/c^2 in p+p collisions at sqrt(s)=200 GeV. The contributions from light meson decays to e^+e^- pairs have been determined based on measurements of hadron production cross sections by PHENIX. They account for nearly all e^+e^- pairs in the mass region below 1 GeV/c^2. The e^+e^- pair yield remaining after subtracting these contributions is dominated by semileptonic decays of charmed hadrons correlated through flavor conservation. Using the spectral shape predicted by PYTHIA, we estimate the charm production cross section to be 544 +/- 39(stat) +/- 142(syst) +/- 200(model) \mu b, which is consistent with QCD calculations and measurements of single leptons by PHENIX.Comment: 375 authors from 57 institutions, 18 pages, 4 figures, 2 tables. Submitted to Physics Letters B. v2 fixes technical errors in matching authors to institutions. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    Search for new physics with same-sign isolated dilepton events with jets and missing transverse energy

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    A search for new physics is performed in events with two same-sign isolated leptons, hadronic jets, and missing transverse energy in the final state. The analysis is based on a data sample corresponding to an integrated luminosity of 4.98 inverse femtobarns produced in pp collisions at a center-of-mass energy of 7 TeV collected by the CMS experiment at the LHC. This constitutes a factor of 140 increase in integrated luminosity over previously published results. The observed yields agree with the standard model predictions and thus no evidence for new physics is found. The observations are used to set upper limits on possible new physics contributions and to constrain supersymmetric models. To facilitate the interpretation of the data in a broader range of new physics scenarios, information on the event selection, detector response, and efficiencies is provided.Comment: Published in Physical Review Letter

    Search for anomalous t t-bar production in the highly-boosted all-hadronic final state

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    A search is presented for a massive particle, generically referred to as a Z', decaying into a t t-bar pair. The search focuses on Z' resonances that are sufficiently massive to produce highly Lorentz-boosted top quarks, which yield collimated decay products that are partially or fully merged into single jets. The analysis uses new methods to analyze jet substructure, providing suppression of the non-top multijet backgrounds. The analysis is based on a data sample of proton-proton collisions at a center-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 5 inverse femtobarns. Upper limits in the range of 1 pb are set on the product of the production cross section and branching fraction for a topcolor Z' modeled for several widths, as well as for a Randall--Sundrum Kaluza--Klein gluon. In addition, the results constrain any enhancement in t t-bar production beyond expectations of the standard model for t t-bar invariant masses larger than 1 TeV.Comment: Submitted to the Journal of High Energy Physics; this version includes a minor typo correction that will be submitted as an erratu

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

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    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Study of J/ψ azimuthal anisotropy at forward rapidity in Pb-Pb collisions at √sNN=5.02 TeV

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    The second (v2) and third (v3) flow harmonic coefficients of J/ψ mesons are measured at forward rapidity (2.5 < y < 4.0) in Pb-Pb collisions at √ sNN = 5.02 TeV with the ALICE detector at the LHC. Results are obtained with the scalar product method and reported as a function of transverse momentum, pT, for various collision centralities. A positive value of J/ψ v3 is observed with 3.7σ significance. The measurements, compared to those of prompt D0 mesons and charged particles at mid-rapidity, indicate an ordering with vn(J/ψ) < vn(D0 ) < vn(h±) (n = 2, 3) at low and intermediate pT up to 6 GeV/c and a convergence with v2(J/ψ) ≈ v2(D0 ) ≈ v2(h±) at high pT above 6–8 GeV/c. In semicentral collisions (5–40% and 10–50% centrality intervals) at intermediate pT between 2 and 6 GeV/c, the ratio v3/v2 of J/ψ mesons is found to be significantly lower (4.6σ) with respect to that of charged particles. In addition, the comparison to the prompt D0 -meson ratio in the same pT interval suggests an ordering similar to that of the v2 and v3 coefficients. The J/ψ v2 coefficient is further studied using the Event Shape Engineering technique. The obtained results are found to be compatible with the expected variations of the eccentricity of the initial-state geometry.publishedVersio
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