57 resultados para Reprodução - Aspectos farmacológicos - Estudos experimentais


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Nowadays, the use of chemicals that satisfactorily meet the needs of different sectors of the chemical industry is linked to the consumption of biodegradable materials. In this context, this work contemplated biotechnological aspects with the objective of developing a more environmentally-friendly corrosion inhibitor. In order to achieve this goal, nanoemulsion-type systems (NE) were obtained by varying the amount of Tween 80 (9 to 85 ppm) a sortitan surfactant named polyoxyethylene (20) monooleate. This NE-system was analyzed using phase diagrams in which the percentage of the oil phase (commercial soybean oil, codenamed as OS) was kept constant. By changing the amount of Tween 80, several polar NE-OS derived systems (O/W-type nanoemulsion) were obtained and characterized through light scattering, conductivity and pH, and further subjected to electrochemical studies. The interfacial behavior of these NE-OS derived systems (codenamed NE-OS1, S2, S3, S4 and S5) as corrosion inhibitors on carbon steel AISI 1020 in saline media (NaCl 3.5%) were evaluated by measurement of Open Circuit Potential (OCP), Polarization Curves (Tafel extrapolation method) and Electrochemical Impedance Spectroscopy (EIS). The analyzed NE-OS1 and NE-OS2 systems were found to be mixed inhibitors with quantitative efficacy (98.6% - 99.7%) for concentrations of Tween 80 ranging between 9 and 85 ppm. According to the EIS technique, maximum corrosion efficiency was observed for some tested NE-OS samples. Additionaly to the electrochemical studies, Analysis of Variance (ANOVA) and Principal Component Analysis (PCA) were used, characterization of the nanoemulsion tested systems and adsorption studies, respectively, which confirmed the results observed in the experimental analyses using diluted NE-OS samples in lower concentrations of Tween 80 (0.5 1.75 ppm)

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Due to its physico-chemical and biological properties, related to the abundance and low cost of raw material, chitosan has been recognized as a material of wide application in various fields, such as in drug delivery systems. Many of these properties are associated with the presence of amino groups in its polymer chain. A proper determination of these amino groups is very important, in order to properly specify if a given chitosan sample can be used in a particular application. Thus, in this work, initially, a comparison between the determination of the deacetylation degree by conductometry and elemental analysis was carried out using a detailed analysis of error propagation. It was shown that the conductometric analysis resulted in a simple and safe method for the determining the degree of deacetylation of chitosan. Subsequently, experiments were performed to monitor and characterize the adsorption of tetracycline on chitosan particles through kinetic and equilibrium studies. The main models of kinetics and adsorption isotherms, widely used to describe the adsorption on wastewater treatment systems and the drug loading, were used to treat the experimental data. Firstly, it was shown that an apparent linear t/q(t) × t relationship did not imply in a pseudo-second-order adsorption kinetics, differently of what has been repeatedly reported in the literature. It was found that this misinterpretation can be avoided by using non-linear regression. Finally, the adsorption of tetracycline on chitosan particles was analyzed using insights obtained from theoretical analysis, and the parameters generated were used to analyze the kinetics of adsorption, the isotherm of adsorption and to ropose a mechanism of adsorption

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In today`s society the use of so-called information technology and communication (ICT), is promoting a revolution in the forms of teaching and learning through the methods of distance learning courses, especially in higher education. Studies show that students in this way have great difficulties in the learning process, especially when dealing with experimental subjects that require high power of abstraction as chemistry. The goal of this work is to promote improvement in the teaching and learning in the discipline Chemistry of Life offered for the Bachelor`s Degree in Chemistry in distance UFRN. For this we analyzed evidence of the semester 2011.2, in order to identify what are the main difficulties of the students on the assessments. That`s why video lessons related to matters that create the majority of difficulties for students were developed, the final product this work. Being obtained the improvements by video classes in the learning process of the students, from a questionnaire answered by the students in the virtual learning environment, and from their success rate at the end of the course

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Textile activity results in effluents with a variety of dyes. Among the several processes for dye-uptaking from these wastewaters, sorption is one of the most effective methods, chitosan being a very promising alternative for this end. The sorption of Methyl Orange by chitosan crosslinked particles was approached using equilibrium and kinetic analyses at different pH s. Besides the standard pseudo-order analysis normally effectuated (i.e. pseudo-first-order and pseudo-second-order), a novel approach involving a pseudo-nth-order kinetics was used, nbeing determined via non-linear regression, using the Levenberg-Marquardt method. Zeta potential measurements indicated that electrostatic interactions were important for the sorption process. Regarding equilibrium experiments, data were well fitted to a hybrid Langmuir-Freundlich isotherm, and estimated Gibbs free energy of adsorption as a function of mass of dye per area of chitosan showed that the process of adsorption becomes more homogeneous as the pH of the continuous phase decreased. Considering the kinetics of sorption, although a pseudo-nth-order description yielded good fits, a kinetic equation involving diffusion adsorption phenomena was found to be more consistent in terms of a physicochemical description of the sorption process

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The development of products whose purpose is to promote blockages in high permeability zones as well as to control the hydrate or scale formation also needs some tests in porous media before using the product in the field, where attempts and unavoidable operational errors costs would able to derail any projects. The aim of this study was to analyze and compare the Botucatu and Berea sandstones properties, involving problems related to loss permeability. It was observed that even cores of Berea, without expansible clays in their composition had their permeability reduced, as soon as the salinity of brine reached a lower limit. As expected, the same happened with the Botucatu sandstone samples, however, in this case, the sensitivity to low salinity was more pronounced. In a second phase, the research was focused on the Botucatu Sandstone behavior front of dilute polymer solutions injection, checking the main relationships between the Rock / Fluid interactions, considering the Mobility Reduction, Resistance and Residual Resistance Factors, as well as adsorption/desorption processes of these polymers, and the polymer molecules average size and porous sandstone average size ratio. The results for both phases showed a real feasibility of using the Botucatu sandstone in laboratory tests whose objective is the displacement of fluids through porous media

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Aspect Oriented approaches associated to different activities of the software development process are, in general, independent and their models and artifacts are not aligned and inserted in a coherent process. In the model driven development, the various models and the correspondence between them are rigorously specified. With the integration of aspect oriented software development (DSOA) and model driven development (MDD) it is possible to automatically propagate models from one activity to another, avoiding the loss of information and important decisions established in each activity. This work presents MARISA-MDD, a strategy based on models that integrate aspect-oriented requirements, architecture and detailed design, using the languages AOV-graph, AspectualACME and aSideML, respectively. MARISA-MDD defines, for each activity, representative models (and corresponding metamodels) and a number of transformations between the models of each language. These transformations have been specified and implemented in ATL (Atlas Definition Language), in the Eclipse environment. MARISA-MDD allows the automatic propagation between AOV-graph, AspectualACME, and aSideML models. To validate the proposed approach two case studies, the Health Watcher and the Mobile Media have been used in the MARISA-MDD environment for the automatic generation of AspectualACME and aSideML models, from the AOV-graph model

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In February 2011, the National Agency of Petroleum, Natural Gas and Biofuels (ANP) has published a new Technical Rules for Handling Land Pipeline Petroleum and Natural Gas Derivatives (RTDT). Among other things, the RTDT made compulsory the use of monitoring systems and leak detection in all onshore pipelines in the country. This document provides a study on the method for detection of transient pressure. The study was conducted on a industrial duct 16" diameter and 9.8 km long. The pipeline is fully pressurized and carries a multiphase mixture of crude oil, water and natural gas. For the study, was built an infrastructure for data acquisition and validation of detection algorithms. The system was designed with SCADA architecture. Piezoresistive sensors were installed at the ends of the duct and Digital Signal Processors (DSPs) were used for sampling, storage and processing of data. The study was based on simulations of leaks through valves and search for patterns that characterize the occurrence of such phenomena

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Decapod crustaceans are one of the most important portions of megafaunal of coastal waters, playing a role as modifier of the environment and controlling populations of other organisms. Among the Decapoda, crab (brachyuran) constitutes the dominant macrofauna of mangroves. Among brachyuran is the mangrove crab (Ucides cordatus, Linnaeus, 1763), which represents the main component of the macrofauna of mangroves, particularly in Northern and Northeastern Brazil. In Brazil, its distribution is known from the state of Amapá to the north of Santa Catarina. This species is distinguished by its economic importance, being one of the main fishing resources in Brazil, generating a significant impact on their natural populations. This reduction would result in loss of value to the product, preventing its commercialization. Although it´s great ecological and economic importance, there are few articles about the biological aspects of U. cordatus, mainly in the state of Rio Grande do Norte. This work aimed to study the population dynamics of the mangrove crab, Ucides cordatus (Linnaeus, 1763), in Conchas estuary, Porto do Mangue, northern coast of Rio Grande do Norte. During the period November 2009 to October 2010 the crabs were collected monthly, obeying predetermined lunar periods (new moon or full moon) in a mangrove area in Porto do Mangue - RN. With the aid of a steel caliper (0.01 mm) and a precision balance (0.01 g) were measured biometric variables related to the animal's carapace, major propodus chela, width of abdomen (female), length of gonopodium ( males) and total weight. In addition, it was recorded, the gonads and molt stages, for males and females. In total, 476 crabs were collected, with 338 males and 138 females. Males were larger, heavier and in greater proportion than females. The reproductive period for the species in this location was limited during the months November to May, suggesting a change in current environmental legislation for the closure period. Synchrony was observed between the morphological and physiological maturity with females maturing earlier, possibly, a reproductive strategy adopted, compared to the low fishing pressure in the area. The molting period occurred in the dry season peaking in October. The analysis of growth, based on the parameters of von Bertalanffy was calculated using the nonlinear fit using modes (AJMOD). High growth rates for both males (L = 7.54 cm, k = 0.95, t0 =- 00:08; tmax = 4.84) and females (L = 6.50, k = 1 , 2, t0 =- 0008; tmax = 3.28) were found, contrasting with data from the literature, using other techniques. Males had higher asymptotic width size and longevity, but a lower growth constant when compared with females. The estimated age, for males and females, reaching the minimum capture size was 1.82 years and 1.63 years respectively. The size of physiological maturity, when individuals are able to reproduce, was estimated at 1.4 years and 1.05 years, for males and females, respectively. The recruitment period for this species is seasonal, with two peaks of occurrence, one in the rainy season and one in the dry season. This work represented the first effort on understanding the ecology of the mangrove crab, to the northern coast of Rio Grande do Norte. However, further studies on its biology should be undertaken, especially those related to growth, and recruitment, where observed that literature is more scarce

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This dissertation presents the results of research developed in the Nísia Floresta-Papeba-Guaraíras Lagoon Complex, located on the south coast of the Rio Grande do Norte State. The main objectives of this dissertation were the stratrigraphic characterization, in detail scale, of the and the coastal dynamics study of the lagoonal deposits sedimentation, as well as the morpho-dynamic analysis of the area. Therefore, an interdisciplinary methodology was adopted, in which all sedimentological, morpho-tectonic and geomorphological data were integrated. Vibracore up to 4m in length were carried out in the lagoons. The referred lagoon complex made of a system of three lagoons that interact through two artificial channels, named Boqueirão and Surubajá. The Guaraíras lagoon, the largest one in the system, corresponds to the estuary zone of the Trairi and Jacu rivers. The sedimentary load brought by these rivers is strongly reworked by tide currents, forming an important net-work of channels and sandy bars inside this lagoon and close to its channel connection with the sea. The stratigraphic units of the area are Cenozoic in age, and are represented by sedimentary rocks of the Barreiras Formation (sandstones, mudstones and conglomerates) and by rocks beach, as well as by siliciclastics sediments related with the fluvial dynamics of tide plain (clay and sandy bars), and coast (sand dunes and beaches). Among the recognized geomorphologic aspects, there are the elements associated with continental enviroments (drainage basins of the Trairi, Baldum and Jacu rivers, coastal tableland supported by the Barreiras Formation), and transitional environments (lagoon complex, dune fields, cliffs, tidal channels and beach rocks lines). The morphotectonic analysis indicates that fauts affect Barreiras Formation sedimentary rocks, with two sets of main lineaments: SW-NE and SE-NW. The anomalies in the drainage net are directly associated with these fault/fracture system, which control and subdivede the low courses of the Trairi and Jacu rivers, at least a tail of their flowing principal courses. The Nísia Floresta, Papeba and Guaraíras lagoons present strong morphological control according to the lineament directions. Taking into account the lagoonal deposits, the sedimentological analyses reflect a sediment distribution related to the interaction of the fluvial and sea processes that act in the study area. The correlated deposits show textural mainly microclastic characteristics of shallow waters, and of currents of low to moderate energy.In general, the Nísia Floresta-Papeba-Guaraíras lagoon Complex, constitutes a very intrinsec group, that undewent important changes in historical times that are reflected in the currents clays. Inaddition to the natural processes that act in this system, we should take into account the antrohopic intervention, which have increased in the past years

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A morpho-structural analysis was performed in the uplifted siliciclastic deposits of the Serra do Martins Formation along the Portalegre, Martins and Santana plateaux, in the southeastern and central regions of Rio Grande do Norte State. Due to the lack of biostratigraphic records, this formation has a disputable age.The adopted approach was based on the analysis of the drainage patterns and in the recognition of topographic surfaces and regional structures, subjected to neotectonic deformation and rejuvenation the present stress field. These events are recorded in the lineament arrays and as anomalous features of the landscape, such as the uplifted plateaux.The morpho-sculptural evolution of the studied blocks is expressed as erosive and accumulative processes. The former ones include erosional scarpments, cuestas and amphitheaters as the most characteristic features, while debris slopes represent acumulative examples. Such elements attest to the recent disequilibrium of the plateaux, and the absence of well developed alluvium terraces suggest an accelerated uplift process. The directions of the linear features observed in remote sensing products evidence the control of the basement structural trends, inherited from the pre-Cenozoic evolution. The NNE-SSW direction controls the main erosional features of the plateaux, while the N-S direction is a major drainage control, being also recognized in the Potiguar Basin. An E-W trend occurs as a less developed direction, reflecting either a system of mesozoic basic dykes or precambrian brittle structures. As regards to the drainage arrays, an arborescent, varying to a roughly N-S rectangular pattern, was identified in the Portalegre-Martins block. The Santana plateau displays rectilinear (northern border) and dendritic arborescent (southern border) patterns. In the sedimentary cover, the drainage pattern varies from rectangular to angular, reflecting inheritance from the crystaline basement. The most significative directions, N, NE and NW, mark the erosional fronts of the plateaux. Drainage anomalies, characterized by elbows or paralell confluencies, reinforce the arguments mentioned above. The data sets evidence the relationships between endogenous (lithology, structures) and exogenous features as the main controls of terrain dissecation, associated to vertical (epirogenesis) movements and horizontal tectonics. A final discussion addresses the relationships of the Serra do Martins Formation with the sedimentary record of Potiguar Basin, trying to establish chronostratigraphic links with the main evolutionary steps of this part of the Borborema Province, and possible mechanisms involved in the uplift of the plateaux and other stratigraphic units in the region

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This dissertation deals with sedimentological and structural framework of the siliciclastic rock of the Serra do Martins Formation (FSM) in the Portalegre, Martins and Santana plateau, located to the south of Potiguar Basin, in the southwest and central Rio Grande do Norte state. This formation, regarded as of Oligo-Miocene age based on intrusive relations of the Miocene Macau volcanics, has a still disputable age due to the lack of appropriate bio and/or chronostratigraphic markers. The FSSM deposits crop out along 650 to 750 m high plateau, as a remanescent sedimentary cover directly overlying topographically uplifted pre-cambrian crystalline rocks. During the last decades, these deposits were interpreted according to a Tertiary paleoclimatic evolutionary model, associated to pedogenetic processes. The sedimentological characterization of the FSM was done through a detailed study of its facies, petrography and diagenetic features. The facies study was based on description of field relations, textures and structures, the piling up of the strata and their lateral variations. The FSM was deposited by an anastomosing to coarse-meandering fluvial system, including deposits of lag, cannel-fill, ouver-bank and flood plain. The petrographic composition of the sediments, coupled to their facies and paleocurrent directions, suggest a rather distal sourcearea, to the south of the present plateau. The diagenetic study identified an incipient grain mechanical compaction, pronounced dissolution of the framework, matrix and/or cement components, intense precipitation of kaolinite, silic and, eventually, iron oxides, besides mechanical infiltration of the clays. Most of these events, regarded in the literature as associated to near-surface conditions (eo or telodiagenesis), indicate the FSM sediments were never deeply buried. Topographic relations along longitudinal and transversal sections reaching the Potiguar Basin to the north identified regional dips that allow to discuss stratigraphic correlations between the FSM and the basin formations. The sedimentological features of the different units and the intrusive relations of the Macau volcanics were also considered in these correlations,which support the Oligo-Miocene age previously accepted for the FSM. Concerning the tectonic framework of the FSM, this work investigated the pre-cambrian to cretaceous heritage and the cenozoic deformation, allowing the recognition of pre-, sin and post-FSM structures. The crystalline basement, belonging to the Seridó Belt, displays NE and WNW foliation trends related to the Brasiliano-age ductile shear zones. In this terrain, brittle-ductile and brittle NE- and NW-trending structures, associated with extensional joints filled with pegmatites and quartz veins, are related to an E-W compression by the end of Brasiliano Cycle. The E-W joints and NE-trending fractures were reactivated by N-S to N-S to NW extension during late Jurassic to Cretaceous times, controlling the emplacement of the Rio Ceará-Mirim basic dyke swarm and the opening of the Potiguar rift basin