11 resultados para STRUCTURE-BASED DRUG DESIGN

em Universidade Federal do Rio Grande do Norte(UFRN)


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Helicobacter pylori is the main cause of gastritis, gastroduodenal ulcer disease and gastric cancer. The most recommended treatment for eradication of this bacteria often leads to side effects and patient poor compliance, which induce treatment failure. Magnetic drug targeting is a very efficient method that overcomes these drawbacks through association of the drug with a magnetic compound. Such approach may allow such systems to be placed slowed down to a specific target area by an external magnetic field. This work reports a study of the synthesis and characterization of polymeric magnetic particles loaded with the currently used antimicrobial agents for the treatment of Helicobacter pylori infections, aiming the production of magnetic drug delivery system by oral route. Optical microscopy, scanning electron microscopy, transmission electron microscopy, x-ray powder diffraction, nitrogen adsorption/desorption isotherms and vibrating sample magnetometry revealed that the magnetite particles, produced by the co-precipitation method, consisted of a large number of aggregated nanometer-size crystallites (about 6 nm), creating superparamagnetic micrometer with high magnetic susceptibility particles with an average diameter of 6.8 ± 0.2 μm. Also, the polymeric magnetic particles produced by spray drying had a core-shell structure based on magnetite microparticles, amoxicillin and clarithromycin and coated with Eudragit® S100. The system presented an average diameter of 14.2 ± 0.2 μm. The amount of magnetite present in the system may be tailored by suitably controlling the suspension used to feed the spray dryer. In the present work it was 2.9% (w/w). The magnetic system produced may prove to be very promising for eradication of Helicobacter pylori infections

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COSTA, Umberto Souza; MOREIRA, Anamaria Martins; MUSICANTE, Matin A.; SOUZA NETO, Plácido A. JCML: A specification language for the runtime verification of Java Card programs. Science of Computer Programming. [S.l]: [s.n], 2010.

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COSTA, Umberto Souza da; MOREIRA, Anamaria Martins; MUSICANTE, Martin A. Specification and Runtime Verification of Java Card Programs. Electronic Notes in Theoretical Computer Science. [S.l:s.n], 2009.

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One of the objectives of this work is the ana1ysis of planar structures using the PBG (photonic Bandgap), a new method of controlling propagation of electromagnetic waves in devices with dielectrics. Here the basic theory of these structures will be presented, as well as applications and determination of certain parameters. In this work the analysis will be performed concerning PBG structures, including the basic theory and applications in planar structures. Considerations are made related to the implementation of devices. Here the TTL (Transverse Transmission Line) method is employed, characterized by the simplicity in the treatment of the equations that govern the propagation of electromagnetic waves in the structure. In this method, the fields in x and z are expressed in function of the fields in the traverse direction y in FTD (Fourier Transform Domain). This method is useful in the determination of the complex propagation constant with application in high frequency and photonics. In this work structures will be approached in micrometric scale operating in frequencies in the range of T erahertz, a first step for operation in the visible spectra. The mathematical basis are approached for the determination of the electromagnetic fields in the structure, based on the method L TT taking into account the dimensions approached in this work. Calculations for the determination of the constant of complex propagation are also carried out. The computational implementation is presented for high frequencies. at the first time the analysis is done with base in open microstrip lines with semiconductor substrate. Finally, considerations are made regarding applications ofthese devices in the area of telecommunications, and suggestions for future

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Among the new drugs launched into the market since 1980, up to 30% of them belong to the class of natural products or they have semisynthetic origin. Between 40-70% of the new chemical entities (or lead compounds) possess poor water solubility, which may impair their commercial use. An alternative for administration of poorly water-soluble drugs is their vehiculation into drug delivery systems like micelles, microemulsions, nanoparticles, liposomes, and cyclodextrin systems. In this work, microemulsion-based drug delivery systems were obtained using pharmaceutically acceptable components: a mixture Tween 80 and Span 20 in ratio 3:1 as surfactant, isopropyl mirystate or oleic acid as oil, bidistilled water, and ethanol, in some formulations, as cosurfactants. Self-Microemulsifying Drug Delivery Systems (SMEDDS) were also obtained using propylene glycol or sorbitol as cosurfactant. All formulations were characterized for rheological behavior, droplet size and electrical conductivity. The bioactive natural product trans-dehydrocrotonin, as well some extracts and fractions from Croton cajucara Benth (Euphorbiaceae), Anacardium occidentale L. (Anacardiaceae) e Phyllanthus amarus Schum. & Thonn. (Euphorbiaceae) specimens, were satisfactorily solubilized into microemulsions formulations. Meanwhile, two other natural products from Croton cajucara, trans-crotonin and acetyl aleuritolic acid, showed poor solubility in these formulations. The evaluation of the antioxidant capacity, by DPPH method, of plant extracts loaded into microemulsions evidenced the antioxidant activity of Phyllanthus amarus and Anacardium occidentale extracts. For Phyllanthus amarus extract, the use of microemulsions duplicated its antioxidant efficiency. A hydroalcoholic extract from Croton cajucara incorporated into a SMEDDS formulation showed bacteriostatic activity against colonies of Bacillus cereus and Escherichia coli bacteria. Additionally, Molecular Dynamics simulations were performed using micellar systems, for drug delivery systems, containing sugar-based surfactants, N-dodecylamino-1-deoxylactitol and N-dodecyl-D-lactosylamine. The computational simulations indicated that micellization process for N-dodecylamino-1- deoxylactitol is more favorable than N-dodecyl-D-lactosylamine system.

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This study aimed to explore the process of reproduction of space from the small family farm production in the municipality of Canguaretama, specifically focused on foodstuffs of plant origin, seeking to understand the changes in agrarian space canguaretamense and its impact on small family farms the last 35 years. Since colonization, during the seventeenth century, the production of space agrarian Canguaretama was founded under a structure based on large ownership and cultivation of cane sugar. Secondly, it was being built a small space reserved for food production to meet both the consumption of property, but also for local marketing. In the centuries following the changes in the capitalist system imposed a new dynamic for small food production, mostly in the early twentieth century, with processing plants and mills in the area extending toward the cultivation of sugarcane. In the second half of that century, mainly in the 1980s, the cultivation of cane sugar was encouraged to produce alcohol, which led to a further expansion of sugar cane toward the areas targeted for the production of foodstuffs. Currently, the framework of small food production differs little from the period of colonization in relation to the difficulties faced by this segment of agriculture. Thus, we have a reality based on socio-spatial inequality, and the near absence of the Government, which requires urgent implementation of public policies for the production and organization of small producers into associations or cooperatives to improve the productivity and hence in their standards of living and their families

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Reverberation is caused by the reflection of the sound in adjacent surfaces close to the sound source during its propagation to the listener. The impulsive response of an environment represents its reverberation characteristics. Being dependent on the environment, reverberation takes to the listener characteristics of the space where the sound is originated and its absence does not commonly sounds like “natural”. When recording sounds, it is not always possible to have the desirable characteristics of reverberation of an environment, therefore methods for artificial reverberation have been developed, always seeking a more efficient implementations and more faithful to the real environments. This work presents an implementation in FPGAs (Field Programmable Gate Arrays ) of a classic digital reverberation audio structure, based on a proposal of Manfred Schroeder, using sets of all-pass and comb filters. The developed system exploits the use of reconfigurable hardware as a platform development and implementation of digital audio effects, focusing on the modularity and reuse characteristics

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Frequency Selective surfaces are increasingly common structures in telecommunication systems due to their geometric and electromagnetic advantages. As a matter of fact, the frequency selective surfaces with fractal geometry type would allow an even bigger reduction of the electrical length which provided greater flexibility in the design of these structures. In this work, we investigated the use of multifractal geometry in frequency selective surfaces. Three structures with different multifractal geometries have been proposed and analyzed. The first structure allowed the design of multiband structures with greater flexibility in controlling the resonant frequencies and bandwidth. The second structure provided a bandwidth increase even with the rising of the fractal level. The third structure showed response with angle stability, dual polarization and provided room for a bandwidth increase with the rising of the structural multifractality. Furthermore, the proposed structures increased the degree of freedom in the multiband designs because they have multiple resonant frequencies ratios between adjacent bands and are easy to deploy. The validation of the proposed structures was initially verified through simulations in Ansoft Designer software and then the structures were constructed and the experimental results obtained

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The Amazon savannas occur as isolated patches throughout extensive areas of forest in the states of Amapá, Amazonas, Pará, and Roraima. There is a considerable variation in the composition of anuran assemblages in the localities and phytophysiognomies of Amazon savannas and given the absence of studies on reproductive behavior, a systematic and geographically wide sampling has been carried out in the Amapá savanna, located in the Eastern Amazon. The study was conducted in a savanna area in the state of Amapá to examine the composition, ecology, and reproductive behavior of anuran amphibians. We carried out 24 field trips in each phytophysiognomy (gramineous-woody savana, gramineous-herbaceous-woody savana, park savana, and arboreal savanna); for analysis of reproductive behavior observations were made during the period January to December 2013, lasting four consecutive days. Samples were collected by active and acoustic search along 20 plots of 100x50 meters. Twenty-one anuran species were recorded, of which four are new records for the state of Amapá: Dendropsophus walfordi, Scinax fuscomarginatus, Pseudopaludicola boliviana e Elachistocleis helianneae. The KruskalWallis ANOVA revealed significant differences between richness and species diversity in the phytophysiognomies (p < 0.05). The Bray-Curtis similarity coefficient divided the phytophysiognomies into three groups: arboreal savana, gramineous-woody savanna and gramineous-herbaceous-woody savanna, and park savanna. According to the non-metric multidimensional scaling, the structure of the anuran community resulted in a separation into three phytophysiognomies, with significant differences in the structure of communities (ANOSIM, R = 0.823; p < 0.001). In the study of community ecology, the results obtained for spatial, temporal, and trophic niche breadth suggest that the assemblage of anurans of the Amapá savanna is not composed of predominantly generalist species. Also, the presence of other specialist anurans may explain the processes of speciation associated with the isolation of habitats, resulting in heterogeneity and spatial discontinuity in the phytophysiognomies with open formations. The null model analysis revealed that the community is structured based on temporal and trophic niche, indicating a significant influence of contemporary ecological factors on the assemblage. The absence of structure based on spatial niche might be explained by the spatial segregation in the distribution and occupation of anurans in the different phytophysiognomies of the Amapá savanna. Regarding the reproductive behavior of anurans, 11 species were classified as having a long breeding season, intrinsically associated with the rainy season and the reproductive mode of most species that lay egg clutches in lentic water bodies. Six reproductive modes were recorded and parental care was observed in Leptodactylus macrosternum and L. podicipinus, whose reproductive mode is characterized by foam nests. Regarding behavioral reproductive strategies, calling males were observed in all species of anurans, satellite males were recorded only for D. walfordi, Hypsiboas multifasciatus, S. nebulosus and S. fuscomarginatus; active search for females was observed for Phyllomedusa hypochondrialis and L. fuscus, and male displacement was recorded only for Rhinella major and R. margaritifera. Of the reproductive behaviors observed, throat and vocal sac display is associated with courtship and territorial behavior exhibited by males. In addition to courtship behavior, visual signals associated with courtship strategies were recorded for the anurans of the Amapá savanna.

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COSTA, Umberto Souza; MOREIRA, Anamaria Martins; MUSICANTE, Matin A.; SOUZA NETO, Plácido A. JCML: A specification language for the runtime verification of Java Card programs. Science of Computer Programming. [S.l]: [s.n], 2010.

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COSTA, Umberto Souza da; MOREIRA, Anamaria Martins; MUSICANTE, Martin A. Specification and Runtime Verification of Java Card Programs. Electronic Notes in Theoretical Computer Science. [S.l:s.n], 2009.