Any periodic signal can be decomposed into a sum of oscillating functions. Traditionally, cosine and sine segments have been used to represent a single period of the periodic signal (Fourier Series). In more general cases, each of these functions can be represented by a set of spectral parameters such as its amplitude, frequency, phase, and the variability of its instantaneous spectral components. The accuracy of these parameters depends on several processing variables such as resolution, noise level, and bias of the algorithm used. This thesis presents some background of existing frequency estimation techniques and proposes a new technique for estimating the instantaneous frequency of signals using short sinusoid-like basis functions. Furthermore, it also shows that the proposed algorithm can be implemented in a popular embedded DSPmicroprocessor for practical use. This algorithm can also be implemented using more complex features on more resourceful processing processors in order to improve estimation accuracy

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2014-11-06T12:42:14Z No. of bitstreams: 2 Tese - Heverton Silva de Camargos - 2013.pdf: 10380072 bytes, checksum: 25d8d3683466bf8825ea9bb7bff97588 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2014-11-06T14:34:39Z (GMT) No. of bitstreams: 2 Tese - Heverton Silva de Camargos - 2013.pdf: 10380072 bytes, checksum: 25d8d3683466bf8825ea9bb7bff97588 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-11-06T14:34:39Z (GMT). No. of bitstreams: 2 Tese - Heverton Silva de Camargos - 2013.pdf: 10380072 bytes, checksum: 25d8d3683466bf8825ea9bb7bff97588 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-11-16 / Outras / Electron paramagnetic resonance (EPR) spectroscopy of spin labels was used to study the main structural accommodations of environment-sensitive probes in the bilayers of saturated phosphatidylcholines with acyl chains lengths ranging from 16 to 22 carbon atoms. The more detailed analysis were made on the spin probe 5-doxyl methyl stearate (5-DMS) whose EPR spectra allowed to identify two distinct spectral components in thermodynamic equilibrium at temperatures below and above the main phase transition. The EPR spectroscopy distinguishes two components associating lower motion with higher polarity (denoted component 1) and higher motion with lower polarity (component 2), which may be assigned to one shallow (more rigid structure) and one deep population of spin probe, respectively. At temperatures until 22◦C only one spectral component can be noted in the spectra whereas at 30◦C the component 1 coexists with an appreciable fraction of component 2. In the liquid-crystalline phase the 5-MSL showed two spectral components for all studied lipids in the entire range of measured temperatures. An accurate analysis of EPR spectra, performed using two fitting programs (NLLS and EPRSIM), allowed us to obtain the thermodynamic profile to these major probe accommodations. Focusing the analysis on two-component EPR spectra, it was studied the influences of cholesterol and a membrane permeation enhancer on the mobility and distribution of spin label on these two main bilayer environments. Parte II Cutaneous leishmaniasis is a neglected tropical disease that infects millions of people worldwide, representing a serious public health problem. The current treatment is based on chemotherapy, using pentavalent antimonials compounds, which cause serious side effects. Electron paramagnetic resonance (EPR) spectroscopy of the spin-label analog of stearic acid (5-DSA ) was used to monitor the effect of the terpenes α-terpineol, 1,8-cineole, III (+)-limonene and nerolidol on the plasma membrane fluidity of Leishmania amazonensis promastigotes. Cytotoxic effects on the parasite were also measured to investigate the relationship between the cytotoxic potential of terpenes and their ability to alter membrane fluidity. All terpenes increased the fluidity of the cellular membrane, without significant differences at higher concentrations. However, the minimum concentration required to cause a change in the membrane was very different between the terpenes and similar to that caused 50% growth inhibition (IC50) showing a correlation between membrane alterations and cytotoxicity. The IC50 values of terpenes analyzed showed the following relationship: nerolidol < (+)-limonene < α-terpineol < 1,8-cineole, with an IC50 of 8 μM for nerolidol and 4700 μM to 1,8- cineole. The EPR spectra of the maleimide derivative spin label (6-MSL) covalently attached to the Leishmania membrane proteins indicated that the terpenes essentially do not alter the dynamics of protein backbone and only increase the mobility of the nitroxide side chain. Cell lysis was not detected at cytotoxic concentrations, as measured by the presence of spin-labeled membrane fragments. Since the terpenes are considered potent skin permeation enhancers with low irritation potential, this work suggests checking the possibility of terpenes applications in the treatment of tegumentary leishmaniasis, where terpenes could perhaps perform a dual action of be an active principle and at the same time facilitate the penetration of other molecules with antileishmanial activity. / Parte I A espectroscopia de Ressonˆancia Paramagn´etica Eletrˆonica (RPE) de marcadores de spin foi usada para estudar as principais acomoda¸c˜oes estruturais de sondas sens´ıveis ao ambiente nas bicamadas de fosfatidilcolinas com cadeias acilas saturadas e de comprimentos variando de 16 a 22 ´atomos de carbono. A an´alise mais detalhada foi feita sobre o marcador de spin 5-metil doxil estearato (5-DMS), cujos espectros de RPE permitiram identificar dois tipos distintos de componentes espectrais em equil´ıbrio termodinˆamico para temperaturas abaixo e acima da principal transi¸c˜ao de fase. A espectroscopia de RPE distingue duas componentes associando menor movimento com maior polaridade (denotado como componente 1) e maior movimento, com menor polaridade (componente 2), as quais podem ser atribu´ıdas a duas popula¸c˜oes de marcadores, sendo uma pr´oxima (estrutura mais r´ıgida) e outra longe da regi˜ao polar da membrana, respectivamente. Em temperaturas de at´e 22◦C apenas uma componente pode ser observada nos espectros enquanto que a 30◦C a componente 1 coexiste com uma fra¸c˜ao significativa da componente 2. Na fase l´ıquido-cristalina o 5-DMS mostrou duas componentes espectrais para todos os lip´ıdios estudados e em todo o intervalo de temperatura medido. Uma an´alise acurada dos espectros de RPE, realizadas utilizando dois programas de ajuste (NLLS e EPRSIM), permitiu-nos obter o perfil termodinˆamico para estas principais acomoda¸c˜oes do marcador. Focalizando nossa an´alise sobre espectros de RPE de duas componentes e usando o mesmo modelo de simula¸c˜ao dos espectros, foi estudada a influˆencia do colesterol e um modificador de permea¸c˜ao de mol´eculas atrav´es da pele, examinando principalmente a mobilidade e a distribui¸c˜ao do marcador de spin nesses dois principais ambientes da bicamada. Parte II A leishmaniose cutˆanea ´e uma doen¸ca tropical negligenciada que infecta milh˜oes de pessoas em todo mundo, representando um grave problema de sa´ude p´ublica. O tra- I tamento atual, baseado em quimioterapia, utiliza compostos pentavalentes antimoniais que causam s´erios efeitos colaterais. A espectroscopia de Ressonˆancia Paramagn´etica Eletrˆonica (RPE) do marcador de spin an´alogo do ´acido este´arico (5-DSA) foi utilizada para monitorar o efeito dos terpenos α-terpineol, 1,8-cineol, (+)-limoneno e nerolidol sobre a fluidez da membrana plasm´atica de promastigotas de Leishmania amazonensis. Os efeitos citot´oxicos sobre os parasitas tamb´em foram medidos para investigar as rela¸c˜oes entre os potenciais citot ´oxicos dos terpenos e suas capacidades de alterar a fluidez da membrana. Todos os terpenos aumentaram a fluidez da membrana celular, sem diferen¸cas significativas para concentra¸c˜oes mais elevadas. Entretanto, a concentra¸c˜ao m´ınima necess´aria para causar a altera¸c˜ao na membrana foi muito diferente entre os terpenos e semelhante daquela que causou 50% de inibi¸c˜ao do crescimento (IC50), denotando uma correla¸c˜ao entre altera¸c˜oes na membrana e citotoxicidade. Os valores de IC50 dos terpenos analisados seguiram a rela¸c˜ao nerolidol < (+)-limoneno < α-terpineol < 1,8-cineol, com um IC50 de 8 μM para o nerolidol e 4700 μM para o 1,8-cineol. Os espectros de RPE do marcador de spin derivado do maleimido (6-MSL) covalentemente ligado `as prote´ınas de membrana da Leishmania indicaram que os terpenos essencialmente n˜ao alteram a dinˆamica do esqueleto prot´eico e apenas aumentam a mobilidade da cadeia lateral do nitr´oxido. A lise celular n˜ao foi detectada nas concentra¸c˜oes de citotoxicidade, quando medida pela presen¸ca de fragmentos de membranas marcadas. Como os terpenos s˜ao considerados potentes facilitadores da permea¸c˜ao atrav´es da pele com baixo potencial de irrita¸c˜ao, este trabalho sugere a realiza¸c˜ao de testes para verificar a possibilidade de aplica¸c˜oes no tratamento da Leishmaniose tegumentar, onde os terpenos talvez pudessem desempenhar uma a¸c˜ao dupla, de ser um principio ativo e ao mesmo tempo facilitar a penetra¸c˜ao de outras mol´eculas com atividade leishmanicida.