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Search Results: 1 - 10 of 204730 matches for " Marcina P.;Azevedo "
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Planktic Cyanobacteria from upper Tietê basin reservoirs, SP, Brazil
Sant'Anna, Célia L.;Melcher, Silvia S.;Carvalho, Maria do Carmo;Gelmego, Marcina P.;Azevedo, Maria Teresa de P.;
Brazilian Journal of Botany , 2007, DOI: 10.1590/S0100-84042007000100002
Abstract: considering the great ecological and sanitary importance of the cyanobacteria and the need of detailed information about these organisms in brazilian water bodies, the present study aims at contributing towards the knowledge of the cyanobacterial flora of five reservoirs belonging to the upper tietê basin, s?o paulo: billings, guarapiranga, jundiaí, pirapora, ponte nova and taia?upeba. in the past several years, these reservoirs have been submitted to severe environmental deterioration and have repeatedly presented cyanobacterial blooms, including those of toxic species. the samples were collected between 1997 and 2003 either with plankton net (20 μm mesh) or van dorn's bottle, and preserved with lugol solution or formaldehyde. some species were isolated and maintained in culture. forty-eight species of cyanobacteria were identified, with predominance of the order chroococcales (58%), followed by the orders oscillatoriales (21%) and nostocales (21%). among the 48 studied species, 17 (35%) were considered potentially toxic. the occurrence and biodiversity of the cyanobacteria in each reservoir depend on the environmental conditions. among the five water bodies, billings reservoir presented the most adequate situation for the development of a greater number of species (34), probably due to its high ph values (around 8). pirapora reservoir on the other hand, with highest conductivity (445.0 μs cm-1) and lowest secchi depth values (0.2 m), presented the lowest cyanobacterial biodiversity (14 species).
Cyanobacterial occurrence and detection of microcystin by planar chromatography in surface water of Billings and Guarapiranga Reservoirs, SP, Brazil
Carvalho, Luciana R. de;Sant'Anna, Célia L.;Gemelgo, Marcina C.P.;Azevedo, Maria Teresa de P.;
Brazilian Journal of Botany , 2007, DOI: 10.1590/S0100-84042007000100014
Abstract: billings and guarapiranga reservoirs were deeply affected by environmental disturbances, which more evident consequence are the cyanobacterial blooms. microcystins are the most common cyanotoxin in freshwaters and more than 70 types are known. different methods for microcystins analysis in water can be used, among which elisa and hplc are the most frequently employed. however, less sophisticated and more economic methods can also be used. this is the case of planar chromatography (thin-layer chromatography) method previously used in cyanotoxins purification but gradually replaced by others. posterior optimization of the microcystin chromatography conditions and because of its simplicity, rapidity, efficiency and low cost, this method is again considered an option for the analysis of microcystins and nodularins. considering the importance of billings and guarapiranga reservoirs for drinking water supplies and the few scientific data about cyanobacteria and cyanotoxins in these water bodies, the aims of this work are to analyze the biodiversity of cyanobacteria in the billings and guarapiranga reservoirs and the detection of dissolved microcystins in the water. it was possible to identify 17 species of cyanobacteria, 9 of them being potentially toxic. in billings reservoir microcystis aeruginosa (kützing) kützing and cylindrospermopsis raciborskii (woloszynska) seenayya & subba raju are the most common species, while in guarapiranga reservoir only m. aeruginosa was considered as a common species. microcystins were detected in all billings reservoir samples and in only one sample from guarapiranga reservoir.
Continuous Symmetric Perturbations of Planar Power Law Forces
C. Azevedo,P. Ontaneda
Mathematics , 2003,
Abstract: We show the existence of periodic solutions for continuous symmetric perturbations of certain planar power law problems.
On the Existence of Periodic Orbits for the Fixed Homogeneous Circle Problem
C. Azevedo,P. Ontaneda
Mathematics , 2005,
Abstract: We prove the existence of some types of periodic orbits for a particle moving in Euclidean three-space under the influence of the gravitational force induced by a fixed homogeneous circle. These types include periodic orbits very far and very near the homogeneous circle, as well as eight and spiral periodic orbits.
Revista de análisis económico , 2010, DOI: 10.4067/S0718-88702010000200002
Abstract: this article reviews evidence on intergenerational social mobility in latin america. results indicate that mobility is low in the region, even when compared with the united states and united kingdom, which rank low on social mobility. the evidence also suggests high levels of immobility at the income distribution's lower and upper tails. while intergenerational education mobility have improved in recent decades, which may increase income mobility for younger cohorts, overall the region still presents lower intergenerational social mobility. previous studies suggest that these results might be associated to social exclusion, low access to higher education, and labor market discrimination.
Traqueostomia percutanea no doente crítico: a experiência de uma unidade de terapia intensiva clínica
Marcelo Park,Luciano C. P. Azevedo
Jornal Brasileiro de Pneumologia , 2004, DOI: 10.1590/s1806-37132004000600021
Araneae, Dipluridae, Trechona venosa Latreille, 1832: First record for the state of Minas Gerais, Brazil, and distribution map.
Azevedo, L. P.,Pedroso, D. R.
Check List , 2010,
Abstract: Herein is reported the first record of Trechona venosa (Araneae, Dipluridae) for the state of Minas Gerais. Theprevious records are restricted to a maximum range of about 50 km from the Atlantic Ocean coast, in the states of Rio deJaneiro and Espírito Santo. The new record extends the species distribution to 200 km far from coast.
On the fixed homogeneous circle problem
C. Azevedo,H. Cabral,P. Ontaneda
Mathematics , 2003,
Abstract: We give some results about the dynamics of a particle moving in Euclidean three-space under the influence of the gravitational force induced by a fixed homogeneous circle. Our main results concern (1) singularities and (2) the dynamics in the plane that contains the circle. The study presented here is purely analytic.
Evapotranspiration and water-use efficiency of irrigated colored cotton cultivar in semiarid regions  [PDF]
Pedro V. de Azevedo, José R. C. Bezerra, Vicente de P. R. da Silva
Agricultural Sciences (AS) , 2012, DOI: 10.4236/as.2012.35086
Abstract: Irrigation studies provide a framework for evaluating agricultural production and the water resource management in locations where water is scarce. Field experiments were conducted at Barbalha- CE (northwestern Brazil) during 2004 and 2005 cropping seasons to investigate the effects of different irrigation water depths on the water-use efficiency and yield of the BRS 200-brown cotton cultivar (Gossypium hirsutum L.). Three irrigation treatments were applied: T1 = 80%; T2 = 100% and T3 = 120% of the potential evapotranspiration (ETp). The Bowen ratio-energy balance was used to obtain crop evapotrnaspiration (ETc) while daily reference evapo-transpiration (ETo) was obtained by the Penman-Monteith approach. Irrigation water was applied by a sprinkler system during both cropping seasons. The daily evapotranspiration ranged from 2.59 mm·day-1 at the emergence to 5.89 mm·day-1 at first square growth stage with an accumulated value of 528.7 mm as a mean of the two cropping seasons. The average crop coefficient across both years (2004-2005) was 0.90, with minimum and maximum values of 0.46 and 1.17 at emergency and first flower growth stages, respectively. The results also showed that the increase in irrigation from 80% to 120% of ETp resulted in a significant increase in the seed-cotton yield (from 2476.0 to 3289.5 kg·ha-1), while lint percentage and water-use efficiency (WUE) were slightly reduced from 35.7% to 35.6% and from 0.60 to 0.53 kg·m-3, respectively. These results suggests that the cotton crop (cultivar BRS-200 brown) reaches higher water-use efficiency when irrigated with 80% of the crop evapotrnaspiration obtained as a function of the reference evapotranspiration and the crop coefficient proposed by FAO. However, the maximum seed-cotton yield is obtained when irrigated with 120% of that crop evapotranspiration.
Chlorambucil Encapsulation into PLGA Nanoparticles and Cytotoxic Effects in Breast Cancer Cell  [PDF]
Diego J. S. Dias, Graziella A. Joanitti, Ricardo B. Azevedo, Luciano P. Silva, Claure N. Lunardi, Anderson J. Gomes
Journal of Biophysical Chemistry (JBPC) , 2015, DOI: 10.4236/jbpc.2015.61001
Abstract: The present work aimed to develop and evaluate a colloidal system composed of poly (DL-lactide-co-glycolide) (PLGA) nanoparticles (NPs) associated with chlorambucil (CHB) and its effects on cancer cells. The nanoparticles showed %EE (>92%), a mean particle size in the range of 240 to 334 nm and zeta potential of -16.7 to -26.0 mV. In vitro release profile showed a biphasic pattern, with an initial burst for all formulations. The scanning electron microscopy of CHB-nanoparticles showed regular spherical shapes, smooth surface without aggregations. Differential scanning calorimetry thermograms, UV-vis absorption, fluorescence emission and Fourier transform infrared spectroscopy were performed showing the entrapment of the antitumoral in drug delivery system. CHB encapsulated in PLGA nanoparticles decrease the survival rates of the breast cancer cells: 68.9% reduction of cell viability on MCF-7 cell line and 59.7% on NIH3T3. Our results indicated that polymeric nanoparticles produced by classical methods are efficient drug delivery systems for CHB.
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