2,906 research outputs found
The force method to calculate stress intensity factors for arbitrary meshes
The force method is a simple and accurate technique to obtain the stress intensity
factors (SIF) for both modes I, II and also mixed I+II modes of fracture. The method uses the summation of internal nodal forces in the vicinity of the crack tip to compute SIFs. Recently, de Morais1 showed that the force method is able to yield accurate SIF values from FE models constructed with regular meshes of linear elements. In this paper, the force method is applied
successfully to general finite element meshes, in such a way that it can be used on crack propagation algorithms with arbitrary crack paths
Heuristic-based fireïŹy algorithm for bound constrained nonlinear binary optimization
FireïŹy algorithm (FA) is a metaheuristic for global optimization. In this paper,we address the practical testing of aheuristic-based FA (HBFA) for computing optimaof discrete nonlinear optimization problems,where the discrete variables are of binary type. An important issue in FA is the formulation of attractiveness of each ïŹreïŹy which in turn affects its movement in the search space. Dynamic updating schemes are proposed for two parameters, one from the attractiveness term and the other from the randomization term. Three simple heuristics capable of transforming real continuous variables into binary ones are analyzed. A new sigmoid âerfâ function is proposed. In the context of FA, three different implementations to incorporate the heuristics for binary variables into the algorithm are proposed. Based on a set of benchmark problems, a comparison is carried out with other binary dealing metaheuristics. The results demonstrate that the proposed HBFA is efïŹcient and outperforms binary versions of differential evolution (DE) and particle swarm optimization (PSO). The HBFA also compares very favorably with angle modulated version of DE and PSO. It is shown that the variant of HBFA based on the sigmoid âerfâ function with âmovements in continuous spaceâ is the best, both in terms of computational requirements and accuracy.Fundação para a CiĂȘncia e a Tecnologia (FCT
Toxicological Study Employing Repeated Doses of Garcinielliptone FC, a Polyisoprenylated-Benzophenone Isolated from Seed of Platonia Insignis Mart
The major constituent from the hexane extract of the seeds of P. insignis is GFC (garcinielliptone FC). Doses of 25, 50and 75 mg/kg of GFC were aseptically suspended in 0.05% Tween 80 dissolved in 0.9% saline (vehicle) and orally administered for30, 90 and 120 consecutive days to adult Swiss mice. In this work, the repeated oral administration, in animals of both sexes,demonstrates that this compound is not able to induce mortality and/or behavioral changes in adult mice. In addition, body weightgain, feed intake and disposal of excreta were not altered by the administration of this compound with repeated doses. Furthermore,no differences in weight and macroscopic structure of the brain, liver, kidney, lung, heart and spleen between groups of male andfemale adult mice were observed after treatment. During the periods of treatment, GFC produced no significant changes onhaematological and biochemical parameters in male and female mice treated with all doses used. The aim of this study was toinvestigate the toxicological potential of GFC through behavioral, hematological, biochemical and morphological parameters inanimals in order to ensure the safe use of Platonia insignis in folk medicine.Fil: Silva, Ana P.. Federal University of PiauĂ; BrasilFil: Filho, JosĂ© Carlos C. L. S.. North Union of Parana; BrasilFil: da Costa JĂșnior, Joaquim S.. Federal Institute of PiauĂ; BrasilFil: PelĂĄez, Walter JosĂ©. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de Investigaciones en FĂsico-quĂmica de CĂłrdoba. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Instituto de Investigaciones en FĂsico-quĂmica de CĂłrdoba; ArgentinaFil: Faillace, MartĂn SebastiĂĄn. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de Investigaciones en FĂsico-quĂmica de CĂłrdoba. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂmicas. Instituto de Investigaciones en FĂsico-quĂmica de CĂłrdoba; ArgentinaFil: FalcĂŁo Ferraz, Alexandre de B.. Lutheran University of Brazil; BrasilFil: David, Jorge M.. Institute Of Chemistry, Federal University Of Bahia; Brasil. Universidade Federal da Bahia; BrasilFil: Freitas, Rivelilson M.. Federal University of Bahia; Brasi
ERP correlates of error processing during performance on the HalsteadCategory Test
The Halstead Category Test (HCT) is a neuropsychological test that measures a person's ability to formulate and
apply abstract principles. Performance must be adjusted based on feedback after each trial and errors are
common until the underlying rules are discovered. Event-related potential (ERP) studies associated with the HCT
are lacking. This paper demonstrates the use of amethodology inspired on Singular SpectrumAnalysis (SSA) applied
to EEG signals, to remove high amplitude ocular andmovement artifacts during performance on the test. This filtering
technique introduces no phase or latency distortions, with minimum loss of relevant EEG information. Importantly,
the test was applied in its original clinical format, without introducing adaptations to ERP recordings. After
signal treatment, the feedback-related negativity (FRN) wave, which is related to error-processing, was identified.
This component peaked around 250ms, after feedback, in fronto-central electrodes. As expected, errors elicited
more negative amplitudes than correct responses. Results are discussed in terms of the increased clinical potential
that coupling ERP informationwith behavioral performance data can bring to the specificity of theHCT in diagnosing
different types of impairment in frontal brain function.info:eu-repo/semantics/publishedVersio
Relation between TNF-alpha and exercise induced bronchoconstriction
Introduction: Exercise-induced bronchoconstriction (EIB) describes an acute airway narrowing that occurs as a result of exercise. EIB is associated with a hyperosmolar environment that lead to airway smooth muscle contraction. The proinïŹammatory cytokine, TNF-alpha, has a prominent role in the development of airway hiperresponsiveness (AHR). A single bout of heavy exercise can trigger EIB. The aim of this research was to compare the response of TNF-alpha over time with the presence or absence of EIB in marathon runners. Methods: Thirty-eight male runners, who did not have any chronic or acute airway disease, performed maximal cardiopulmonary exercise testing on a treadmill coupled to the gas analyzer (FitMate âą, Cosmed, Italy). Was used a ramp protocol with fixed slope of 1% and an increase of load (1km/h) every minute. Spirometry was performed before (pre), immediately after, five, ten, fifteen and twenty minutes after exercise stress testing. Were considered positive for BIE those athletes that presented a decrease in expiratory volume in one second greater than 10% in any of the spirometric tests. Blood samples were obtained the day before the marathon, immediately and after 72 hours after the race. Cytokines were determined in serum by ELISA. Was used analysis of variance (ANOVA) with two factors, group and time of blood collection, considering repeated measures on the time factor. In the case of statistical significance for interaction group and blood was concluded that the behavior over time was significantly different between EIB negative (-) and EIB positive (+), in this case applied the method of Tukey\u27s multiple comparisons to determine the moment that occurred these differences (p\u3c0.05). Results: We observed a statistically significant difference (p=0.048) in the behavior of the concentration of TNF-alpha between groups EIB- and EIB+. The measure pre of the EIB+ have an higher concentration of TNF-alpha compared to those obtained immediately after the marathon for EIB+ and the results obtained at the three moments for EIB-. (Figure 1). Conclusion: Our results suggests that an inflammatory status in serum of the marathon runners presenting BIE, before the race may be associated with bronchoconstriction triggering
Functional analyses of <i>Agaricus bisporus </i>Serine Proteinase 1 (SPR1) reveals a role in utilisation of humic rich substrates and adaptation to the leaf-litter ecological niche
Agaricus bisporus is a secondary decomposer fungus and an excellent model for the adaptation, persistence and growth of fungi in humicârich environments such as soils of temperate woodland and pastures. The A. bisporus serine proteinase SPR1 is induced by humic acids and is highly expressed during growth on compost. Three Spr1 gene silencing cassettes were constructed around sense, antisense and nonâtranslatableâstop strategies (pGRsensehph, pGRantihph and pGRstophph). Transformation of A. bisporus with these cassettes generated cultures showing a reduction in extracellular proteinase activity as demonstrated by the reduction, or abolition, of a clearing zone on plateâbased bioassays. These lines were then assessed by detailed enzyme assay, RTâqPCR and fruiting. Serine proteinase activity in liquid cultures was reduced in 83% of transformants. RTâqPCR showed reduced Spr1 mRNA levels in all transformants analysed, and these correlated with reduced enzyme activity. When fruiting was induced, highlyâsilenced transformant AS5 failed to colonize the compost, whilst for those that did colonize the compost, 60% gave a reduction in mushroom yield. Transcriptional, biochemical and developmental observations, demonstrate that SPR1 has an important role in nutrient acquisition in compost and that SPR1 is a key enzyme in the adaptation of Agaricus to the humicârich ecological niche formed during biomass degradation
Study Bioprospecting of Medicinal Plant Extracts of the Semiarid Northeast: Contribution to the Control of Oral Microorganisms
Dental pathologies can be caused by plaque-forming bacteria and yeast, which reside in the oral cavity. The bacteria growing in dental plaque, a naturally occurring biofilm, display increased resistance to antimicrobial agents. The objective was the evaluation of a preclinical assay of medicinal plants of the semiarid region from the northeast against oral pathogenic microorganism, aiming at bioprospecting a new product. The selection of plant material for this study was based on the ethnobotanical data on the traditional use of plants from the semiarid region. The thirty extracts were subjected to the determination of antibiofilm activity against gram-positive, gram-negative bacteria and yeast. The hydroalcoholic extract which showed positive antibiofilm activity against most of the microorganisms tested in agar diffusion assay was further tested for the determination of minimum inhibitory concentration (MIC) and Bioassay with Artemia salina. Plant samples tested in this study exhibited good antibiofilm activity for the treatment of oral problems. The Schinopsis brasiliensis showed greater activity for Pseudomonas aeruginosa and Staphylococcus aureus, but toxicity against Artemia salina
Effects of Resistance Exercise on Endothelial Progenitor Cell Mobilization in Women
This study aimed to determine the effect of a single bout of resistance exercise at different intensities on the mobilization of circulating EPCs over 24âhours in women. In addition, the angiogenic factors stromal cell-derived factor 1 (SDF-1α), vascular endothelial growth factor (VEGF), hypoxia-inducible factor 1-alpha (HIF-1α) and erythropoietin (EPO) were measured as potential mechanisms for exercise-induced EPCs mobilization. Thirty-eight women performed a resistance exercise session at an intensity of 60% (nâ=â13), 70% (nâ=â12) or 80% (nâ=â13) of one repetition maximum. Each session was comprised of three sets of 12 repetitions of four exercises: bench press, dumbbell curl, dumbbell squat, and standing dumbbell upright row. Blood was sampled at baseline and immediately, 6âhours, and 24âhours post-exercise. Circulating EPC and levels of VEGF, HIF-1α and EPO were significantly higher after exercise (Pâ\u3câ0.05). The change in EPCs from baseline was greatest in the 80% group (Pâ\u3câ0.05), reaching the highest at 6âhours post-exercise. The change in EPCs from baseline to 6âhours post-exercise was correlated with the change in VEGF (râ=â0.492, Pâ=â0.002) and HIF-1α (râ=â0.388, Pâ=â0.016). In general, a dose-response relationship was observed, with the highest exercise intensities promoting the highest increases in EPCs and angiogenic factors
Toxicity effects of ethanol extract of Simarouba versicolor on reproductive parameters in female Wistar rats
Simarouba versicolor is popularly known as pau-paraiba. It belongs to the Simaroubaceae family and is found in the Northeast of São Paulo and in some parts of the states of Parå and Mato Grosso do Sul. It is known that this and other species from this genus have several activities: insecticides, antiinflammatory, antitumor, anthelmintic, among others. The effects of ethanolic extract of the bark of S. versicolor (Sv-EtOH) on the reproductive system of rats were investigated; also the influence of estrogenic and/or antiestrogenic activity, estrous cycle, pregnancy, lactation and offspring development was observed. In the experimental protocols with ethanolic extract of S. versicolor, the doses were 10, 20 and 40 mg/kg. To evaluate estrogenic and anti-estrogenic activity, uterotrophic assay and histopathology of the uterus were performed. In the estrous cycle tests, animals were treated daily, for 30 days, to count number of cycles and record the biochemical profile. During pre-implantation and post-implantation, the effect of the extract on pregnancy, lactation and development of the progeny was observed. Uterotrophic assay exhibited anti-estrogenic activity at extract doses of 10, 20 and 40 mg/kg. The animals exposed to all doses had no changes in their estrous cycle, pregnancy, lactation and biochemical profile. All results were within normal range; however, creatinine concentration increased significantly at all doses as compared to the control. The ethanol extract of S. versicolor presented antiestrogen activity, low systemic toxicity and had no reproductive toxicity at investigated doses.Key words: Simarouba versicolor, reproduction, rats
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