7 resultados para SFS 6000

em Universidade Federal do Rio Grande do Norte(UFRN)


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This thesis aimed to assess the increase in solubility of simvastatin (SINV) with solid dispersions using techniques such as kneading (MA), co-solvent evaporation (ES), melting carrier (FC) and spray dryer (SD). Soluplus (SOL), PEG 6000 (PEG), PVP K-30 (PVP) e sodium lauryl sulphate (LSS) were used as carriers. The solid dispersions containing PEG [PEG-2(SD)], Soluplus [SOL-2(MA)] and sodium lauryl sulphate [LSS-2(ES)] were presented with a greater increase in solubility (5.02, 5.60 and 5.43 times respectively); analyses by ANOVA between the three groups did not present significant difference (p<0.05). In the phase solubility study, the calculation of the Gibbs free energy (ΔG) revealed that the spontaneity of solubilisation of SINV occurred in the order SOL>PEG >PVP 75%>LSS, always 80%. The phase diagrams of PEG and LSS presented solubilization stoichiometry of type 1:1 (type AL). The diagrams with PVP and SOL tend to 1:2 stoichiometry (type AL + AP). The stability coefficients (Ks) of the phase diagrams revealed that the most stable reactions occurred with LSS and PVP. The solid dispersions were characterized by Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), particle size distribution (PSD), near-infrared spectroscopy imaging (NIR-CI) and X-ray diffraction of the powder using the Topas software (PDRX-TOPAS). The solid dispersion PEG-2(SD) presented the greatest homogeneity and the lowest degree of crystallinity (18.2%). The accelerated stability study revealed that the solid dispersions are less stable than SINV, with PEG-2(SD) being the least stable, confirmed by FTIR and DSC. The analyses by PDRX-TOPAS revealed the amorphous character of the dispersions and the mechanism of increasing solubility

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The need for new sources of energy and the concern about the environment have pushed the search for renewable energy sources such as ethanol. The use of lignocellulosic biomass as substrate appears as an important alternative because of the abundance of this raw material and for it does not compete with food production. However, the process still meets difficulties of implementation, including the cost for production of enzymes that degrade cellulose to fermentable sugars. The aim of this study was to evaluate the behavior of the species of cactus pear Opuntia ficus indica and Nopalea cochenillifera, commonly found in northeastern Brazil, as raw materials for the production of: 1) cellulosic ethanol by simultaneous saccharification and fermentation (SSF) process, using two different strains of Saccharomyces cerevisiae (PE-2 and LNF CA-11), and 2) cellulolytic enzymes by semi-solid state fermentation (SSSF) using the filamentous fungus Penicillium chrysogenum. Before alcoholic fermentation process, the material was conditioned and pretreated by three different strategies: alkaline hydrogen peroxide, alkaline using NaOH and acid using H2SO4 followed by alkaline delignification with NaOH. Analysis of composition, crystallinity and enzymatic digestibility were carried out with the material before and after pretreatment. In addition, scanning electron microscopy images were used to compare qualitatively the material and observe the effects of pretreatments. An experimental design 2² with triplicate at the central point was used to evaluate the influence of temperature (30, 40 and 45 °C) and the initial charge of substrate (3, 4 and 5% cellulose) in the SSF process using the material obtained through the best condition and testing both strains of S. cerevisiae, one of them flocculent (LNF CA-11). For cellulase production, the filamentous fungus P. chrysogenum was tested with N. cochenillifera in the raw condition (without pretreatment) and pretrated hydrothermically, varying the pH of the fermentative medium (3, 5 and 7). The characterization of cactus pear resulted in 31.55% cellulose, 17.12% hemicellulose and 10.25% lignin for N. cochenillifera and 34.86% cellulose, 19.97% hemicellulose and 15.72% lignin for O. ficus indica. It has also been determined, to N. cochenillifera and O. ficus indica, the content of pectin (5.44% and 5.55% of calcium pectate, respectively), extractives (26.90% and 9.69%, respectively) and ashes (5.40% and 5.95%). Pretreatment using alkaline hydrogen peroxide resulted in the best cellulose recovery results (86.16% for N. cochenillifera and 93.59% for O. ficus indica) and delignification (48.79% and 23.84% for N. cochenillifera and O. ficus indica, respectively). This pretreatment was also the only one which did not increase the crystallinity index of the samples, in the case of O. ficus indica. However, when analyzing the enzymatic digestibility of cellulose, alkali pretreatment was the one which showed the best yields and therefore it was chosen for the tests in SSF. The experiments showed higher yield of conversion of cellulose to ethanol by PE-2 strain using the pretreated N. cochenillifera (93.81%) at 40 °C using 4% initial charge of cellulose. N. cochenillifera gave better yields than O. ficus indica and PE-2 strain showed better performance than CA-11. N. cochenillifera proved to be a substrate that can be used in the SSSF for enzymes production, reaching values of 1.00 U/g of CMCase and 0.85 FPU/g. The pretreatment was not effective to increase the enzymatic activity values

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ROTATION is one the most important aspects to be observed in stellar astrophysics. Here we investigate that particularly in stars with planets. This physical parameter supplies information about the distribution of angular momentum in the planetary system, as well as its role on the control of dierent phenomena, including coronal and cromospherical emission and on the ones due of tidal effects. In spite of the continuous solid advances made on the study of the characteristics and properties of planet host stars, the main features of their rotational behavior is are not well established yet. In this context, the present work brings an unprecedented study about the rotation and angular momentum of planet-harbouring stars, as well as the correlation between rotation and stellar and planetary physical properties. Our analysis is based on a sample of 232 extrasolar planets, orbiting 196 stars of dierent luminosity classes and spectral types. In addition to the study of their rotational behavior, the behavior of the physical properties of stars and their orbiting planets was also analyzed, including stellar mass and metallicity, as well as the planetary orbital parameters. As main results we can underline that the rotation of stars with planets present two clear features: stars with Tef lower than about 6000 K have slower rotations, while among stars with Tef > 6000 K we and moderate and fast rotations, though there are a few exceptions. We also show that stars with planets follow mostly the Krafts law, namely < J > / v rot. In this same idea we show that the rotation versus age relation of stars with planets follows, at least qualitatively, the Skumanich and Pace & Pasquini laws. The relation rotation versus orbital period also points for a very interesting result, with planet-harbouring stars with shorter orbital periods present rather enhanced rotation

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Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq

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The pioneering work proposed by Skumanich (1972) has shown that the projected mean rotational velocity < v sini > for solar type stars follows a rotation law decreases with the time given by t −1/2 , where t is the stellar age. This relationship is consistent with the theories of the angular momentum loss through the ionized stellar wind, which in turn is coupled to the star through its magnetic field. Several authors (e.g.: Silva et al. 2013 and de Freitas et al. 2014) have analyzed the possible matches between the rotational decay and the profile of the velocity distribution. These authors came to a simple heuristic relationship, but did not build a direct path between the exponent of the rotational decay (j) and the exponent of the distribution of the rotational velocity (q). The whole theoretical scenario has been proposed using an efficient and strong statistical mechanics well known as non-extensive statistical mechanics. The present dissertation proposes effectively to close this issue by elaborating a theoretical way to modify the q-Maxwellians’ distributions into q-Maxwellians with physics links extracted from the theory of magnetic braking. In order to test our distributions we have used the GenevaCapenhagen Survey data with approximately 6000 F and G field stars limited by age. As a result, we obtained that the exponents of the decay law and distribution follow a similar relationship to that proposed by Silva et al. (2013).

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This study was conducted in the adjacent Brazilian equatorial inner shelf to Rio Grande do Norte, between the region of Porto do Mangue and Galinhos. The main objective is the characterization of biogenic sediments, especially foraminifera and ostracod collected on the surface of the seafloor. The methodology involved standard procedures including literature, surveys, processing of samples in the laboratory and identification of foraminifera and ostracods by genera or species under stereo microscopy and scanning electron microscopy (SEM). Multivariate statistical analyzes and study of ecological indexes were also applied to the study of foraminifera. Three transects, from inner shelf to slope were sampled: profile 01 (east, near Galos), profile 02 (center, near the city of Macau) and profile 03 (west, near Ponta do Mel). Results indicated the predominance of benthic foraminifera and little plankton occurrence. Benthic foraminifera genera observed in abundance were Quinqueloculina, Textularia, Globigerina and Pyrgo, Quinqueloculina, Textularia, Pyrgo, Ammonia, Elphidium, Pseudononion, Peneroplis, Bolivina and Poroeponides, occurred more frequently. Less frequently been described Amphistegina, Archaias, Bigenerina, Cibicides, Cassidulina, Amphicorina, Cornuspira, Paterina, Hopkunsina, Oolina, Uvigerina, Fusenkoina, Nonionella, Amphisorus, Wiesrella, Reussella, Reophax, Nodosaria, Marginulina and Cyclogyra. Six genera of ostracods were also identified: Puriana variabilis / P. convoluted?, Loxoconcha sp, Bairdiidae, Xestoleberis sp, Hemicytheridae and Ruggiericythere sp. Groups of organisms found in the studied shelf presented chemical composition of Ca, C, O, Na, Cl, Al, Mg, and Si. The proportions of chemical elements may vary according to the type of biogenic sediment, with the highest values identified as Ca, C, Cl, Na and O. The absolute dating by carbon 14 method indicated sediments of different colors (light and dark), correspond to a single age from 3000 to 6000 years BP, related to the Quaternary. These data intend to complement information about biogenic sediments in the Brazilian continental shelf, especially in the Northeast, where there is a lack of such studies.

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This study was conducted in the adjacent Brazilian equatorial inner shelf to Rio Grande do Norte, between the region of Porto do Mangue and Galinhos. The main objective is the characterization of biogenic sediments, especially foraminifera and ostracod collected on the surface of the seafloor. The methodology involved standard procedures including literature, surveys, processing of samples in the laboratory and identification of foraminifera and ostracods by genera or species under stereo microscopy and scanning electron microscopy (SEM). Multivariate statistical analyzes and study of ecological indexes were also applied to the study of foraminifera. Three transects, from inner shelf to slope were sampled: profile 01 (east, near Galos), profile 02 (center, near the city of Macau) and profile 03 (west, near Ponta do Mel). Results indicated the predominance of benthic foraminifera and little plankton occurrence. Benthic foraminifera genera observed in abundance were Quinqueloculina, Textularia, Globigerina and Pyrgo, Quinqueloculina, Textularia, Pyrgo, Ammonia, Elphidium, Pseudononion, Peneroplis, Bolivina and Poroeponides, occurred more frequently. Less frequently been described Amphistegina, Archaias, Bigenerina, Cibicides, Cassidulina, Amphicorina, Cornuspira, Paterina, Hopkunsina, Oolina, Uvigerina, Fusenkoina, Nonionella, Amphisorus, Wiesrella, Reussella, Reophax, Nodosaria, Marginulina and Cyclogyra. Six genera of ostracods were also identified: Puriana variabilis / P. convoluted?, Loxoconcha sp, Bairdiidae, Xestoleberis sp, Hemicytheridae and Ruggiericythere sp. Groups of organisms found in the studied shelf presented chemical composition of Ca, C, O, Na, Cl, Al, Mg, and Si. The proportions of chemical elements may vary according to the type of biogenic sediment, with the highest values identified as Ca, C, Cl, Na and O. The absolute dating by carbon 14 method indicated sediments of different colors (light and dark), correspond to a single age from 3000 to 6000 years BP, related to the Quaternary. These data intend to complement information about biogenic sediments in the Brazilian continental shelf, especially in the Northeast, where there is a lack of such studies.