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Search Results: 1 - 10 of 408433 matches for " PEREIRA R. C "
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Alterations in growth and branching of Neurospora crassa caused by sub-inhibitory concentrations of antifungal agents
Pereira,R. C.; Said,S.;
Revista argentina de microbiolog?-a , 2009,
Abstract: six antifungal agents at subinhibitory concentrations were used for investigating their ability to affect the growth and branching in neurospora crassa. among the antifungals herein used, the azole agent ketoconazole at 0.5 μg/ml inhibited radial growth more than fluconazole at 5.0 μg/ml while amphotericin b at 0.05 μg/ml was more effective than nystatin at 0.05 μg/ml. morphological alterations in hyphae were observed in the presence of griseofulvin, ketoconazole and terbinafine at the established concentrations. the antifungal agents were more effective on vegetative growth than on conidial germination. terbinafine markedly reduced growth unit length (gu) by 54.89%, and caused mycelia to become hyperbranched. in all cases, there was a high correlation between hyphal length and number of tips (r > 0.9). all our results showed highly significant differences by anova, (p < 0.001, α = 0.05). considering that the hyphal tip is the main interface between the fungus and its environment /through which enzymes and toxins are secreted and nutrients absorbed, it would not be desirable to obtain a hyperbranched mycelia with inefficient doses of antifungal drugs.
Alterations in growth and branching of Neurospora crassa caused by sub-inhibitory concentrations of antifungal agents Alteraciones de crecimiento y ramificación en Neurospora crassa provocadas por concentraciones subinhibitorias de agentes antimicóticos
R. C. Pereira,S. Said
Revista argentina de microbiolog?-a , 2009,
Abstract: Six antifungal agents at subinhibitory concentrations were used for investigating their ability to affect the growth and branching in Neurospora crassa. Among the antifungals herein used, the azole agent ketoconazole at 0.5 μg/ml inhibited radial growth more than fluconazole at 5.0 μg/ml while amphotericin B at 0.05 μg/ml was more effective than nystatin at 0.05 μg/ml. Morphological alterations in hyphae were observed in the presence of griseofulvin, ketoconazole and terbinafine at the established concentrations. The antifungal agents were more effective on vegetative growth than on conidial germination. Terbinafine markedly reduced growth unit length (GU) by 54.89%, and caused mycelia to become hyperbranched. In all cases, there was a high correlation between hyphal length and number of tips (r > 0.9). All our results showed highly significant differences by ANOVA, (p < 0.001, α = 0.05). Considering that the hyphal tip is the main interface between the fungus and its environment /through which enzymes and toxins are secreted and nutrients absorbed, it would not be desirable to obtain a hyperbranched mycelia with inefficient doses of antifungal drugs. Se investigó el efecto de seis agentes antimicóticos en concentraciones subinhibitorias sobre el crecimiento y la ramificación en Neurospora crassa. El agente azólico ketoconazol a la concentración de 0,5 μg/ml inhibió el crecimiento radial más que el fluconazol a 5,0 μg/ml, y la anfotericina B a 0,05 μg/ ml fue más eficiente que 0,05 μg/ml de nistatina, entre los agentes poliénicos usados. En presencia de griseofulvina, ketoconazol y terbinafina a las concentraciones establecidas se observaron alteraciones morfológicas en las hifas. Los agentes antimicóticos fueron más eficientes sobre el crecimiento vegetativo que sobre la germinación conidial. La terbinafina redujo marcadamente (54,89%) la longitud de la unidad de crecimiento y provocó la hiperramificación del micelio. En todos los casos, existió gran correlación entre la longitud y el número de ápices de las hifas (r > 0,9). Todos los resultados mostraron diferencias altamente significativas de acuerdo con ANOVA (p < 0,001, α = 0,05). Considerando que el ápice de la hifa es la principal interfase entre el hongo y su ambiente, a través de la cual las enzimas y las toxinas son secretadas y los nutrientes son absorbidos, un micelio hiperramificado resultante de dosis ineficientes de agentes antimicóticos sería perjudicial.
PET Oligomer Waste to Modify CAP Characteristics  [PDF]
L. C. Mendes, M. L. Dias, P. S. C. Pereira, L. M. R. Albuquerque
Materials Sciences and Applications (MSA) , 2012, DOI: 10.4236/msa.2012.38082
Abstract: To develop an improved method of reusing poly(ethylene terephthalate) (PET) waste in the production chain, it was chemically modified with pentaerythritol (PENTE), resulting in PET/PENTE (60/40) oligomer. This was added to petroleum asphalt cement (CAP) in different proportions—5, 10 and 20 wt%—as a modifier of bitumen characteristics. The mixture was evaluated by thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), optical microscopy (OM) and the adhesion-peel test. The oligomer enhanced substantially the asphalt thermal stability-Tonset. OM images showed strong compatibility between components and PET’s amorphization. PET oligomer increased CAP’s wettability and the mixture presented cohesive fracture through the peel test. The mixture has excellent potential as paving material.
Resveratrol Reverses the Impaired Vasodilation Observed in 2K-1C Hypertension through Endothelial Function Improvement  [PDF]
B. F. M. Pereira, A. C. Scalabrini, T. S. Marinho, C. R. K. Antonietto, C. B. A. Restini
Open Journal of Medicinal Chemistry (OJMC) , 2014, DOI: 10.4236/ojmc.2014.42004
Abstract:
Background: The production of endothelial-derived factors induces either vasoconstriction or vasodilation; nitric oxide (NO) is the most distinguished relaxing factor. Endothelial dysfunction is associated with hypertension. The partial loss in the NO-promoted vasodilation is due to its decreased bioavailability and/or to an activity reduction of endothelium NO synthase (eNOS). Reactive oxygen species (ROS), present in oxidative stress, seize NO and diminish its bioavailability. Transresveratrol (RESV) has been proved to increase NO and eNOS levels. Thus, RESV could be capable of improving NO dependent vascular relaxation on aortic rings isolated from treated 2K-1C animals through ROS damage reduction. Aim: Evaluate the effects of RESV treatment on the relaxation of aortic rings isolated from treated 2K-1C rats while focusing on the effects of the treatment on systolic blood pressure. Methods: Male Wistar rats (180 g) were grouped: two 2K-1C and two Sham groups, one of each was treated with RESV (20 mg/kg, gavage) dissolved in Tween 80 and one of each was treated with water plus Tween 80 (control) for six weeks. The rats had their systolic blood pressure (SBP) measured before and after the treatments. Vascular reactivity studies were conducted in order to observe and compare acetylcholine (ACh)-induced relaxations in the presence and absence of the NOS inhibitor L-NAME (10-4 mol/L). Results: SBP for 2K-1C was significantly reduced in the treated group (179.13 ± 4.90 mmHg, n = 23) when compared to the untreated group (196.66 ± 6.06 mmHg, n = 15, p < 0.01). The maximum relaxation of aortic rings isolated from the 2K-1C treated group showed a higher efficacy (116.63% ± 1.72%, n = 12) than that from the untreated group (85.97% ± 0.69%, n = 6, p < 0.001); L-NAME exposure was responsible for a significant decrease in each group’s maximum relaxation efficacy. Conclusions: SBP reduction observed after RESV treatment in rat renal hypertension could be due to the reestablishment of vascular relaxation depend of NO.
Low temperature dynamics of nonlinear Luttinger liquids
C. Karrasch,R. G. Pereira,J. Sirker
Physics , 2014, DOI: 10.1088/1367-2630/17/10/103003
Abstract: We generalize nonlinear Luttinger liquid theory to describe the dynamics of one-dimensional quantum critical systems at low temperatures. Analyzing density-matrix renormalization group results for the spin autocorrelation function in the XXZ chain we provide, in particular, direct evidence for spin diffusion in sharp contrast to the exponential decay in time predicted by conventional Luttinger liquid theory. Furthermore, we discuss how the frequencies and exponents of the oscillatory contributions from the band edges are renormalized by irrelevant interactions and obtain excellent agreement between our finite temperature nonlinear Luttinger liquid theory and the numerical data.
Gravitational Collapse of Cylindrical Shells Made of Counter-Rotating Dust Particles
P. R. C. T. Pereira,Anzhong Wang
Physics , 2000, DOI: 10.1103/PhysRevD.67.129902
Abstract: The general formulas of a non-rotating dynamic thin shell that connects two arbitrary cylindrical regions are given using Israel's method. As an application of them, the dynamics of a thin shell made of counter-rotating dust particles, which emits both gravitational waves and massless particles when it is expanding or collapsing, is studied. It is found that when the models represent a collapsing shell, in some cases the angular momentum of the dust particles is strong enough to halt the collapse, so that a spacetime singularity is prevented from forming, while in other cases it is not, and a line-like spacetime singularity is finally formed on the symmetry axis.
Dynamics of Rotating Cylindrical Shells in General Relativity
P. R. C. T. Pereira,Anzhong Wang
Physics , 2000, DOI: 10.1023/A:1001954604324
Abstract: Cylindrical spacetimes with rotation are studied using the Newmann-Penrose formulas. By studying null geodesic deviations the physical meaning of each component of the Riemann tensor is given. These spacetimes are further extended to include rotating dynamic shells, and the general expression of the surface energy-momentum tensor of the shells is given in terms of the discontinuation of the first derivatives of the metric coefficients. As an application of the developed formulas, a stationary shell that generates the Lewis solutions, which represent the most general vacuum cylindrical solutions of the Einstein field equations with rotation, is studied by assuming that the spacetime inside the shell is flat. It is shown that the shell can satisfy all the energy conditions by properly choosing the parameters appearing in the model, provided that $ 0 \le \sigma \le 1$, where $\sigma$ is related to the mass per unit length of the shell.
Does Pro12Ala Polymorphism Enhance the Physiological Role of PPAR 2?
A. C. Pereira,R. Oliveira,A. C. Castro,R. Fernandes
PPAR Research , 2013, DOI: 10.1155/2013/401274
Abstract: Obesity and type 2 diabetes mellitus (T2D) are two major public health problems that have motivated the scientific community to investigate the high contribution of genetic factors to these disorders. The peroxisome proliferator activated by gamma 2 (PPAR 2) plays an important role in the lipid metabolism. Since PPAR 2 is expressed mainly in adipose tissue, a moderate reduction of its activity influences the sensitivity to insulin, diabetes, and other metabolic parameters. The present study aims to contribute to the elucidation of the impact of the Pro12Ala polymorphism associated with T2D and obesity through a meta-analysis study of the literature that included approximately 11500 individuals, from which 3870 were obese and 7625 were diabetic. Statistical evidence supports protective effect in T2D of polymorphism Pro12Ala of PPAR 2 (OR?=?0.702 with 95% CI: 0.622; 0.791, ). Conversely the same polymorphism Pro12Ala of PPAR 2 seems to favor obesity since 1.196 more chance than nonobese was found (OR?=?1.196 with 95% CI: 1.009; 1.417, ). Our results suggest that Pro12Ala polymorphism enhances both adipogenic and antidiabetogenic physiological role of PPAR . Does Pro12Ala polymorphism represent an evolutionary step towards the stabilization of the molecular function of PPAR transcription factor signaling pathway? 1. Introduction Peroxisome proliferator-activated receptors (PPARs) are transcription factors from nuclear receptor’s protein family that regulate target genes’ expression by connecting to response elements of peroxisomes proliferators (PPERs) in regulating sites of each gene. The signal transduction mechanism of these receptors involves retinol X receptor (RXR) and PPARs form heterodimers that regulate the transcription of several genes (Figure 1) [1–3]. Figure 1: PPAR transduction pathway. PPAR has several extracellular and intracellular ligands that include dietary and bioactive lipids. Given its antidiabetogenic role, some PPAR ligands include antidiabetic drugs such as thiazolidinediones. PPAR is also modulated by several growth factor transduction pathways such as Jnk/Erk/MKP. It is also known that cyclin-dependent kinase 5 (Cdk5) bond to p25 (a product of the cleavage of p35 in obesity environment) inhibits PPAR pathway by its phosphorylation. As a transcriptional factor, PPAR binds to RXR (retinol X receptor) in order to transcribe several genes related to adipocyte differentiation and lipid storage in adipose tissue and increase insulin sensitivity in peripheral tissues by indirect increase of AMP kinase activity as well as several other
Spinning process variables and polymer solution effects in the die-swell phenomenon during hollow fiber membranes formation
Pereira, C.C.;Nobrega, R.;Borges, C.P.;
Brazilian Journal of Chemical Engineering , 2000, DOI: 10.1590/S0104-66322000000400024
Abstract: during hollow fiber spinning many variables are involved whose effects are still not completely clear. however, its understanding is of great interest because the control of these variables may originate membranes with the desired morphologies and physical properties. in this work, the phase inversion process induced by the immersion precipitation technique was applied to prepare hollow fibers membranes. it was verified that some of the variables involved, can promote a visco-elastic polymer solution expansion, called die-swell phenomenon, which is undesired since it may lead to low reproducibility of the permeation properties. the effects of the distance between spinneret and precipitation bath, the bore liquid composition, and the polymer solution composition were analyzed and discussed in order to avoid this phenomenon. according to the results, it was verified that the parameters investigated might promote a delay precipitation, which restrained the visco-elastic expansion.
Concentra § μes de sel anio na dieta e nas unhas de pr -escolares de um centro de educa § £o infantil de S £o Paulo-SP
Selenium in diet and nails of preschool from the nursery in S £o Paulo, Brazil

C. R. SILVA,A. C. PEREIRA,C. K. MIYASAKA
Alimentos e Nutri??o , 2011,
Abstract: O estudo objetivou determinar a concentra § £o de sel anio nas unhas e na dieta consumida por 66 pr -escolares matriculados em um Centro de Educa § £o Infantil do Munic -pio de S £o Paulo. Para a obten § £o do consumo alimentar foi utilizado o m todo de registro alimentar, com a aplica § £o da pesagem direta dos alimentos. Os teores de sel anio na dieta e nas unhas foram determinados por espectrometria de absor § £o at ′mica em forno de gra te. A ingest £o m dia de sel anio das crian §as de 2 a 3 anos foi de 18,7 g/dia e das de 4 a 6 anos de 29,5 g/dia. Os teores de sel anio nas unhas das crian §as de 2 a 3 anos foi 0,50 g/g e nas de 4 a 6 anos 0,48 g/g. Os resultados sugerem que os pr -escolares recebem na institui § £o uma alimenta § £o adequada com rela § £o ao sel anio.
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