686 research outputs found

    Multi-objective genetic algorithm applied to spectroscopic ellipsometry of organic-inorganic hybrid planar waveguides

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    The applicably of multi-objective optimization to ellipsometric data analysis is presented and a method to handle complex ellipsometric problems such as multi sample or multi angle analysis using multi-objective optimization is described. The performance of a multi-objective genetic algorithm (MOGA) is tested against a single objective common genetic algorithm (CGA). The procedure is applied to the characterization (refractive index and thickness) of planar waveguides intended for the production of optical components prepared sol-gel derived organic-inorganic hybrids, so-called di-ureasils, modified with zirconium tetrapropoxide, Zr(OPr(n))(4) deposited on silica on silicon substrates. The results show that for the same initial conditions, MOGA performs better than the CGA, showing a higher success rate in the task of finding the best final solution. (C) 2010 Optical Society of AmericaFCTFEDERPTDC/CTM/72093/2006SFRH/BD/41943/2007MP070

    Humic-like substances from urban waste as auxiliaries for photo-Fenton treatment: a fluorescence EEM-PARAFAC study

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    In this work, analysis of excitation-emission-matrices (EEM) has been employed to gain further insight into the characterization of humic like substances (HLS) obtained from urban wastes (soluble bio-organic substances, SBOs). In particular, complexation of these substances with iron and changes along a photo-Fenton process have been studied. Recorded EEMs were decomposed by using parallel factor analysis (PARAFAC). Three fluorescent components were identified by PARAFAC modeling of the entire set of SBO solutions studied. The EEM peak locations (λex/λem) of these components were 310?330 nm/400?420 nm (C1), 340?360 nm/450?500 nm (C2), and 285 nm/335?380 nm (C3). Slight variations of the maximum position of each component with the solution pH were observed. The interaction of SBO with Fe(III) was characterized by determining the stability constants of the components with Fe(III) at different pH values, which were in the order of magnitude of the ones reported for humic substances and reached their highest values at pH = 5. Photochemical experiments employing SBO and Fe(III), with and without H2O2, showed pH-dependent trends for the evolution of the modeled components, which exhibited a strong correlation with the efficiency reported for the photo-Fenton processes in the presence of SBO at different pH values.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

    Bio-based substances from urban waste as auxiliaries for solar photo-Fenton treatment under mild conditions: optimization of operational variables

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    The use of soluble bio-based organic substances (SBO) obtained from urban wastes to expand the pH region where the photo-Fenton process can be applied has been investigated in this study. For this purpose, a mixture of six pollutants, namely acetaminophen, carbamazepine, amoxicillin, acetamiprid, clofibric acid and caffeine, at an initial concentration of 5 mg L−1 each, has been employed. Surface response methodology, based on the Doehlert matrix, has shown to be a useful tool to determine the effect of pH (in the range 3–7), concentration of SBO (15–25 mg L−1) and iron (2–6 mg L−1) on the performance of the photodegradation of the studied pollutants, measured by their half-life. Results indicate that, at high SBO concentration, the optimum pH shifts in most cases to a higher value (between 3 and 4) and that a significant loss of efficiency of the process was only observed at pH values above 5. An iron concentration of 4–5 mg L−1 and an amount of SBO of 19–22 mg L−1 have been determined to be the optimal conditions for the degradation of most of the studied pollutants at pH = 5.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

    New edible coatings composed of galactomannans and collagen blends to improve the postharvest quality of fruits: influence on fruits gas transfer rate

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    The objective of this work was to produce new edible coatings, based on a mixture of galactomannans from novel sources (seeds of Adenanthera pavonina and Caesalpinia pulcherrima), collagen and glycerol, and to determine their influence in gas transfer rates when they are applied on mangoes and apples. The first part of the work consisted in obtaining coating solutions with the convenient values of wettability for each fruit; such coating solutions were then characterized in terms of their permeability (to CO2, O2 and water vapour), mechanical properties, colour and opacity. Gas transfer rates from mangoes coated with a solution of A. pavonina galactomannan (0.5%), collagen (1.5%) and glycerol (1.5%) were compared with those of mangoes without coating: 28% less O2 consumption and 11% less CO2 production were observed in coated mangoes. The same procedure was performed in apples (in this case using C. pulcherrima galactomannan (0.5%), collagen (1.5%) and no glycerol); the CO2 production and the O2 consumption was approximately 50% lower in apples with coating than in apples without coating. The results suggest that these coatings can reduce gas transfer rates in these fruits, and can be therefore important tools to extend their shelf life.The author A.M. Lima was the recipient of fellowship from ALFA VALNATURA Project of the Europe Aid Cooperation Office, M.A.Cerqueira is recipient of a fellowship from Fundação para a Ciência e Tecnologia (FCT, SFRH/BD/23897/2005) and B.W.S. Souza is a recipient of a fellowship from the Coordenação Aperfeiçoamento dePessoal de Nível Superior, Brazil (Capes, Brazil)

    Metodologia de avaliação da vulnerabilidade sísmica: calibração e validação macrossísmica

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    As metodologias disponíveis para estudar a vulnerabilidade sísmica do edificado tradicional de alvenaria em centros urbanos antigos, atendendo à escala e ao número de edifícios a avaliar, diferenciam-se marcadamente pelo volume de trabalho associado ao levantamento de informação, e seu tratamento, decorrente do processo de inspeção e do nível de detalhe associado. A metodologia aqui apresentada para a avaliação da vulnerabilidade sísmica de edifícios em alvenaria é baseada em estudos e levantamentos de danos pós-sismo, que evidenciam algumas das características que governam o comportamento das estruturas de alvenaria de edifícios antigos quando sujeitos à ação sísmica. Estas características são posteriormente tratadas como parâmetros a analisar na definição e construção de um índice de vulnerabilidade. Assim, neste artigo, a metodologia original apresentada é calibrada com base na informação recolhida após o sismo dos Açores de 1998, que infligiu graves danos em grande parte do edificado da Ilha do Faial. Esta calibração permitiu redefinir os pesos dos parâmetros e reclassificar as classes de vulnerabilidade de alguns dos parâmetros da metodologia de avaliação da vulnerabilidade sísmica.info:eu-repo/semantics/publishedVersio

    Proteínas morfogenéticas óseas (BMPs): Efecto de la proteína osteogénica-1 (OP-l/BMP-7) en la condrogénesis y osteogenesis

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    En la actualidad, los estudios sobre biología molecular han facilitado el análisis de ciertos factores de transformación del crecimiento tipo ß(TGF-ß)I, entre los que destaca una familia de proteínas morfogenéticas óseas (BMPs). Las técnicas de ingeniería genética han permitido replicar alguno de estos factores y localizar los genes que codifican dichas proteínas. La proteína osteogenics-1 (OP-1) ha sido caracterizada y sintetizada in vitro y muestra un elevado potencial osteogénico y condrogénico tanto in vivo como in vitro. Se presenta una revisión de los últimos avances en la aplicación experimental de las BMPs, y especialmente de la OP-1, en el área de la Cirugía Ortopédica y la TraumatologíaNowadays, molecular biology studies have promoted the bone morphogenetic proteins (BMPs) analysis. These multifunctional proteins are structurally related to transforming growth factor-6 (TGF-6). Genetic engineering techniques have allowed to sequence some of these BMPs. It has been characterized the expression and processing of osteogenic protein-1 (OP-1), a bone morphogenetic protein of the TGF-6 family. The OP-1 shows a high osteogenic and chondrogenic potential. The aim of this paper is to review some updated advances of the BMPs experimental applications, particularly OP-1, in relation to Orthopaedic Surgery and Traumatolog

    Biologically-active compounds from Brazilian lichens and their affinity with ether

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    It can be obtained from lichens biologically-active extracts and pure substances, many of them of phenolic nature. They are usually obtained by using organic solvents, such as diethyl ether. In this paper the usefulness of ether for the obtainment of crude extracts and the subsequent purification of pure substances from Brazilian lichen is reviewed, as well as alternatives to their production through cells or thallus immobilization in bioreactors and their entrapment in inert matrix

    Effect of protective coatings on the water absorption and mechanical properties of 3D printed PLA

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    This work aims to study the influence of protective coatings on the water absorption and mechanical properties of 3D printed polyꖖlactic acid (PLA) parts. The PLA parts were fabricated with different levels of the 3D printing process parameters, aiming to define samples with distinct strength and ductility/toughness characteristics. Water absorption tests following the standard ASTM D570�98 were performed on uncoated and coated PLA specimens. The effectiveness of two protective coatings based on acrylic and polyurethane varnish on reducing water absorption was evaluated. Both protective coatings have shown being effective on preventing water absorption by the PLA, with polyurethane presenting the best performance reducing water absorption by 38%. Tensile tests were carried out to determine the ultimate tensile strength, elastic modulus, yield tensile strength, fracture strain and toughness of specimens, before and after the application of protective coatings. The polyurethane protective coating also benefits the tensile properties of PLA parts, increasing the strength and ductility/toughness characteristics of specimens up to 24%

    Somatostatin subtype-2 receptor-targeted metal-based anticancer complexes

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    Conjugates of a dicarba analogue of octreotide, a potent somatostatin agonist whose receptors are overexpressed on tumor cells, with [PtCl 2(dap)] (dap = 1-(carboxylic acid)-1,2-diaminoethane) (3), [(η 6-bip)Os(4-CO 2-pico)Cl] (bip = biphenyl, pico = picolinate) (4), [(η 6-p-cym)RuCl(dap)] + (p-cym = p-cymene) (5), and [(η 6-p-cym)RuCl(imidazole-CO 2H)(PPh 3)] + (6), were synthesized by using a solid-phase approach. Conjugates 3-5 readily underwent hydrolysis and DNA binding, whereas conjugate 6 was inert to ligand substitution. NMR spectroscopy and molecular dynamics calculations showed that conjugate formation does not perturb the overall peptide structure. Only 6 exhibited antiproliferative activity in human tumor cells (IC 50 = 63 ± 2 μ in MCF-7 cells and IC 50 = 26 ± 3 μ in DU-145 cells) with active participation of somatostatin receptors in cellular uptake. Similar cytotoxic activity was found in a normal cell line (IC 50 = 45 ± 2.6 μ in CHO cells), which can be attributed to a similar level of expression of somatostatin subtype-2 receptor. These studies provide new insights into the effect of receptor-binding peptide conjugation on the activity of metal-based anticancer drugs, and demonstrate the potential of such hybrid compounds to target tumor cells specifically. © 2012 American Chemical Society

    Holistic assessment of the microbiome dynamics in the substrates used for commercial champignon (Agaricus bisporus) cultivation

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    Microorganisms strongly influence and are required to generate the selective substrate that provides nutrients and support for fungal growth, and ultimately to induce mushroom fructification under controlled environmental conditions. In this work, the fungal and bacterial microbiota living in the different substrates employed in a commercial crop (compost phase I, II and III, flush 1 and 2, and casing material on day 1, 6 and 8 after compost casing and during flush 1 and 2) have been characterized along the different stages of cultivation by metataxonomic analysis (16S rRNA and ITS2), analysis of phospholipid fatty acid content (PLFAs) and RT-qPCR. Additionally, laccase activity and the content of lignin and complex carbohydrates in compost and casing have been quantified. The bacterial diversity in compost and casing increased throughout the crop cycle boosted by the connection of both substrates. As reflected by the PLFAs, the total living bacterial biomass appears to be negatively correlated with the mycelium of the crop. Agaricus bisporus was the dominant fungal species in colonized substrates, displacing the pre-eminent Ascomycota, accompanied by a sustained increase in laccase activity, which is considered to be a major product of protein synthesis during the mycelial growth of champignon. From phase II onwards, the metabolic machinery of the fungal crop degrades lignin and carbohydrates in compost, while these components are hardly degraded in casing, which reflects the minor role of the casing for nourishing the crop. The techniques employed in this study provide a holistic and detailed characterization of the changing microbial composition in commercial champignon substrates. The knowledge generated will contribute to improve compost formulations (selection of base materials) and accelerate compost production, for instance, through biotechnological interventions in the form of tailored biostimulants and to design environmentally sustainable bio-based casing materialsThe project was funded by the H2020 programme under the Marie Sklodowska-Curie grant agreement no. 742966 and also funded by the ADER project grant no. 2016-IDD-00013. [Correction added on 07 August 2020 after first online publication: Figures 3 and 5 have been corrected in this version
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