Mostrando recursos 1 - 20 de 1.933

  1. Alguns aspetos da floração e vingamento do abacateiro

    Duarte, Amílcar; Lopes, Rosário; Furtado, José; Duarte, João
    Artigo de divulgação científica

  2. Methanol extracts from Cystoseira tamariscifolia and Cystoseira nodicaulis are able to inhibit cholinesterases and protect a human dopaminergic cell line from hydrogen peroxide-induced cytotoxicity

    Custódio, Luísa; Silvestre, Laura; Rocha, Maria Isabel; Rodrigues, Maria João; Vizetto-Duarte, Catarina; Pereira, Hugo; Barreira, Luisa; Varela, J.
    Context Marine macroalgae contain several bioactive molecules that may be developed as functional foods, but information about their neuroprotective potential is scarce.Objective The objective of this study is to determine the in vitro antioxidant and neuroprotective features of marine algae from the southern coast of Portugal and to assess the total content of different types of bioactives.Materials and methods Methanol extracts from 21 macroalgal species from the southern Portugal were evaluated for in vitro antioxidant and acetylcholinesterase (AChE) inhibition. Active extracts were further evaluated for inhibitory activity against butyrylcholinesterase (BuChE) and tyrosinase (TYRO), and for their ability to attenuate hydrogen...

  3. Profiling of antioxidant potential and phytoconstituents of Plantago coronopus

    Pereira, C. G.; Custódio, L.; Rodrigues, M. J.; Neng, N. R.; Nogueira, J. M. F.; Carlier, J.; Costa, Maria Clara; Varela, J.; Barreira, Luísa
    The halophyte species Plantago coronopus has several described ethnomedicinal uses, but few reported biological activities. This work carried out for the first time a comparative analysis of P. coronopus organs in terms of phenolic composition and antioxidant activity of organic and water extracts from roots, leaves and flowers. The leaves contents in selected nutrients, namely amino acids and minerals, are also described. Roots (ethyl acetate and methanol extracts) had the highest radical scavenging activity (RSA) towards 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, while leaves (hexane extract) had higher RSA on nitric oxide radical and iron chelating ability. High performance...

  4. Characterization and refinement of growth related quantitative trait loci in European sea bass (Dicentrarchus labrax) using a comparative approach

    Louro, Bruno; Kuhl, Heiner; Tine, Mbaye; de Koning, Dirk-Jan; Batargias, Costas; Volckaert, Filip A. M.; Reinhardt, Richard; Canário, Adelino V. M.; Power, Deborah
    The identification of genetic markers for traits of interest for aquaculture, such as growth, is an important step for the establishment of breeding programmes. As more genomic information becomes available the possibility of applying comparative genomics to identify and refine quantitative trait locus (QTLs) and potentially identify candidate genes responsible for the QTL effect may accelerate genetic improvement in established and new aquaculture species. Here we report such an approach on growth related traits in the European sea bass (Dicentrarchus labrax), an important species for European aquaculture. A genetic map was generated with markers targeted to previously identified QTL for...

  5. Practice of martial arts and bone mineral density in adolescents of both sexes

    Ito, Igor Hideki; Mantovani, Alessandra Madia; Agostinete, Ricardo Ribeiro; Costa Junior, Paulo; Zanuto, Edner Fernando; Christofaro, Diego Giulliano Destro; Ribeiro, Luís; Fernandes, Rômulo Araújo
    The purpose of this study was to analyze the relationship between martial arts practice (judo, karate and kung-fu) and bone mineral density in adolescents.METHODS: The study was composed of 138 (48 martial arts practitioners and 90 non-practitioners) adolescents of both sexes, with an average age of 12.6 years. Bone mineral density was measured using Dual-Energy X-ray Absorptiometry in arms, legs, spine, trunk, pelvis and total. Weekly training load and previous time of engagement in the sport modality were reported by the coach. Partial correlation tested the association between weekly training load and bone mineral density, controlled by sex, chronological age,...

  6. Numerical simulation of the application of solar radiant systems, internal airflow and occupants' presence in the improvement of comfort in winter conditions

    Conceição, E. Z. E.; Lúcio, M. Manuela J. R.
    In this work, the use of numerical simulation in the application of solar radiant systems, internal airflow and occupants' presence in the improvement of comfort in winter conditions is made. The thermal comfort, the local thermal discomfort and the air quality in an occupied chamber space are evaluated. In the experimental measurements, a wood chamber, a desk, two seats, two seated hygro-thermal manikins, a warm radiant floor, a solar radiation simulator and a water solar collector are used. The air velocity and the air temperature fluctuation are experimentally evaluated around 15 human body sections. The chamber surface temperature is experimentally...

  7. The status of Ischnura senegalensis (Odonata: Coenagrionidae) in Cape Verde

    Loureiro, Nuno de Santos; Martins, S.
    The first record of a zygopteran breeding population in the Cape Verde archipelago is presented. A small population of Ischnura senegalensis (Rambur, 1842) was found living in the lagoon 'Lagoinha', Santiago island, where the species was observed in all seven surveys conducted between May 2014 and June 2015. Reproductive behaviour was repeatedly observed and exuviae were found and collected.

  8. Can macroalgae provide promising anti-tumoral compounds? A closer look at Cystoseira tamariscifolia as a source for antioxidant and anti-hepatocarcinoma compounds

    Vizetto-Duarte, Catarina; Custódio, Luísa; Acosta, Gerardo; Lago, João H. G.; Morais, Thiago R.; de Sousa, Carolina Bruno; Gangadhar, Katkam N.; Rodrigues, Maria João; Pereira, Hugo; Lima, Raquel T.; Helena Vasconcelos, M.; Barreiro, Luísa; Rauter, Amélia P.; Albericioi, Fernando; Varela, J.
    Marine organisms are a prolific source of drug leads in a variety of therapeutic areas. In the last few years, biomedical, pharmaceutical and nutraceutical industries have shown growing interest in novel compounds from marine organisms, including macroalgae. Cystoseira is a genus of Phaeophyceae (Fucales) macroalgae known to contain bioactive compounds. Organic extracts (hexane, diethyl ether, ethyl acetate and methanol extracts) from three Cystoseira species (C. humilis, C. tamariscifolia and C. usneoides) were evaluated for their total phenolic content, radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'- azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals, and antiproliferative activity against a human hepatocarcinoma cell line...

  9. Estimation of gillnet and hook selectivity for Carangoides fulvoguttatus (Forsskal, 1775) captured off Kanyakumari coast of India

    Balasubramanian, A.; Meenakumari, B.; Pravin, P.; Dhanapal, K.; Boopendranath, M. R.; Erzini, Karim
    Selectivity and fishing powers of multi-mesh gillnets with mesh sizes of 13.5, 14, 14.5 and 15 cm and hooks No. 5, 6, 7 and 8 were studied using the experimental catch data of the carangid Carangoides fulvoguttatus (Forsskal, 1775). The selectivity curves, parameters and residual plots for different models viz., normal scale, normal location, log-normal, gamma and bi-normal models were produced applying the SELECT (Share Each Length Class Total) methodology which has been incorporated in the software GILLNET (Generalised Including Log-Linear N Estimation Technique). The models were evaluated using the statistical tools viz., model deviance, dispersion parameter and residual plots...

  10. Determination of temperature effecton the measurements of pKa of some weak acids and weak bases using capillary zone electrophoresis

    Gravador, Rufielyn Sungcaya
    This study was done to determine the pKa values of a number of weak acidic and basic compounds at different temperatures and to be able to identify the effects of temperature variations in the measured pKa using capillary zone electrophoresis. The method employed was adopted from Fuguet et al [12] in which internal standard is used. Running buffers of different pH were prepared. The maximum voltage was chosen based from Ohm’s law to reduce the Joule heating effects. Considering the linearity in the relationship between voltage and current to be with an r2≥0.999, the maximum voltage was found to be...

  11. Speciation of chromium in Algeciras bay

    Assefa, Anteneh Taye
    Algeciras Bay is exposed to contamination from chromium because of the industrial activities carring out around the water, i.e Steel Industry and two Petrol Refineries can be mentioned. More over there are several activities which are being carried out including big ports, fishing and recreational activities. Most of the other trace metals in the water have been studied. Considering the environmental and health effects of this metal, study of its level and speciacion in the bay is necessary for wellbeing of all which are directly or indirectly dependent on this water. Unfiltered samples were used for total chromium determination and filtered samples were used for the other...

  12. Decavanadate Toxicology and Pharmacological Activities: V-10 or V-1, Both or None?

    Aureliano, M.
    This review covers recent advances in the understanding of decavanadate toxicology and pharmacological applications. Toxicological in vivo studies point out that V-10 induces several changes in several oxidative stress parameters, different from the ones observed for vanadate (V-1). In in vitro studies with mitochondria, a particularly potent V-10 effect, in comparison with V-1, was observed in the mitochondrial depolarization (IC50 = 40 nM) and oxygen consumption (99 nM). It is suggested that mitochondrial membrane depolarization is a key event in decavanadate induction of necrotic cardiomyocytes death. Furthermore, only decavanadate species and not V-1 potently inhibited myosin ATPase activity stimulated by...

  13. On a one-equation turbulent model with feedbacks

    de Oliveira, H. B.; Paiva, A.
    A one-equation turbulent model is derived in this work on the basis of the approach used for the k-epsilon model. The novelty of the model consists in the consideration of a general feedback forces field in the momentum equation and a rather general turbulent dissipation function in the equation for the turbulent kinetic energy. For the steady-state associated boundary value problem, we prove the uniqueness of weak solutions under monotonous conditions on the feedbacks and smallness conditions on the solutions to the problem. We also discuss the existence of weak solutions and issues related with the higher integrability of the...

  14. Multi-class, multi residue method for determination of penicillins, cephalosporins and quinolones in cow milk and validation in accordance with Commission Decision 2002/657/E C

    Amatya, Rameshwari
    The method was developed to determine simultaneously 19 drugs of three classes (seven Penicillins and Cephalosporins, and five Quinolones) regulated by European legislation 2377/90/EC in cow milk using LC-MS/MS. To make the sample preparation as simple as possible deproteinization step using organic solvent was eliminated. SPE clean up and concentration was done using OASIS HLB cartridge. The separation of 19 antibiotics was achieved in 11 minutes using C8 column with gradient elution. MS data was acquired on MRM mode with two transitions for each compound. Validation procedure was conducted based on European directive 2002/657/EC. 89% of drugs presented recoveries higher than 65 % with exception of AMOX (57%) and...

  15. Determination of cyclophosphamide in human urine by HPLC coupled to tandem mass spectrometry

    Marahatta, Anu
    Biological samples urine are much more complex due to presence of proteins, salts, acids, bases and various organic compounds with similar chemistry to analytes of interest. As a result, the extraction methods for biological samples have been difficult. The main task was to remove maximum interfering substance from urine matrix and conversion of analytes into a more suitable form for injection. Therefore, optimization of SPE method was done by changing different parameter such as different type and amount of sorbent, composition and volume of elution, washing solvent. The use of 24 well SPE plate for matrix purification significantly allows the use of small urine and solvent volumes,...

  16. Evolution problems of Navier-Stokes type with anisotropic diffusion

    Antontsev, S. N.; de Oliveira, H. B.
    In this work, we consider the evolutive problem for the incompressible Navier-Stokes equations with a general diffusion which can be fully anisotropic. The existence of weak solutions is proved for the associated initial problem supplemented with no-slip boundary conditions. We prove also the properties of extinction in a finite time, exponential time decay and power time decay. With this respect, we consider the important case of a forces fields with possible different behavior in distinct directions. Perturbations of the asymptotically stable equilibrium are established as well.

  17. Simple and effective chitosan based films for the removal of Hg from waters: Equilibrium, kinetic and ionic competition

    Rocha, Luciana S.; Almeida, Ângela; Nunes, Cláudia; Henriques, Bruno; Coimbra, Manuel A.; Lopes, Cláudia B.; Silva, Carlos M.; Duarte, Armando C.; Pereira, Eduarda
    The efficiency of chitosan cross-linked with genipin (Chg) and cross-linked with genipin and grafted with caffeic acid (Ch(g+car)) to remove Hg(II) from waters was investigated. An optimal dose of 50 mg L-1 for both chitosan films was selected based on the equilibrium removal percentage and on the contact time required to attain the equilibrium. The sorption extent was dependent on the initial Hg(II) concentration (C-Hg,C-0), with removal efficiencies varying between 79% and 82% for C-Hg,C-0 = 0.05 mg L-1 and between 89% and 94% for C-Hg,C-0 = 0.50 mg L-1. Under ion competition, the Ch(g) and Ch(g+caf) films showed to...

  18. Process monitoring of continuous flow organic syntheses by means of inline fiber optical Raman spectroscopy

    Rehman, Muhammad Saif Ur
    The objective of the current study was to investigate the feasibility of the inline optical fiber Raman spectroscopy as a tool for the process monitoring of the continuous flow organic syntheses. The synthesis of 2-bromo-3,4,5-trimethoxytoluene (product) was studied as a model reaction under a set of different conditions. The reaction was carried out under the batch as well as in the multi jet oscillating disc (MJOD) milli reactor. The reaction was varied by doubling the concentration of the substrate; 3,4,5-trimethoxytoluene (0.15M, 0.3M and 0.6M) whereas the concentration of the solvent (acetic anhydride) was kept constant. The Raman instrument was adjusted to record five spectra per minute. The...

  19. Quality system design and implementation in proficiency test provider laboratory based in an international norm

    Pereira, Glauce Guimarães
    Proficiency testing is defined as the use of interlaboratory comparisons to determine the performance of individual laboratories for specific tests or measurements and to monitor laboratories‘ continuing performance. The number of PTs is increasing in the last years because the result of this exercise is useful not just for costumers, but also for other interested parties, such as regulators, laboratory accreditation bodies and other organizations who specify requirements for laboratories. Hence, it is very important to organize PT with criteria, focus and quality. The objective of this work was design of a quality system in Mat Control Laboratory of the University of...

  20. Speciation of mercury in environmental samples

    Ruiz , Wilder Leonardo Gamboa
    Mercury is one of the most toxic elements impacting on human and ecosystem health and therefore is one of the most studied environmental pollutants. All mercury species are toxic, with organic mercury compounds generally being more toxic than inorganic species. For this reason, the assessment of mercury distribution in environmental samples is a key task in analytical chemistry. Reverse phase chromatography (RPC) coupled to a UV post-column oxidation system and vapor generation atomic fluorescence spectrometry was optimised for the speciation and determination of inorganic and organic mercury (methylmercury and ethylmercury) in the form of APDC complexes. The mercury-APDC complexes were separated on a reverse phase column and oxidized on-line...

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