Made available in DSpace on 2015-04-14T13:58:45Z (GMT). No. of bitstreams: 1 436435.pdf: 2585417 bytes, checksum: b29fdea176ca870153d00a4ebc8a0345 (MD5) Previous issue date: 2012-01-26 / One area of nanotechnology of great interest is the formation of nanoparticles (nanospheres and nanocapsules) because it allows the development of controlled release formulations, in other words, those with the ability to properly release the actives agents. In such products, the active ingredient protected is gradually released through appropriate stimulus. There is a special interest in the preparation of nanoparticles of biodegradable polymers, for example, polyesters such as poly-lactic acid and glycolic and its copolymers, such as acid poly(lactic-co-glycolic) (PLGA), considering its biocompatibility and biodegradation. In this context, this study has as objective to produce nanospheres from the PLGA biodegradable polymer containing menthol through the technique of multiple emulsion/solvent evaporation. The prepared PLGA / menthol micro and nanospheres, presented mostly average diameters between 217 and 13,103 nm, Tg 41 ?C and thermal stability up to 260 ?C. The presence of menthol in the micro and nanospheres was demonstrated by the characterization techniques used, as well as the physical presence of menthol aroma perceptiple to the smell. At last, was made a preliminary valuation of the efficiency of incorporation of aroma, showing to be effective, since the micro and nanospheres with a higher concentration of menthol in its formulation demonstrated from the techniques used (relation between the heights of the bands of menthol and PLGA in IR and through the higher mass loss relative to the menthol in the TGA), present approximately 60% more menthol incorporated into the polymer matrix of these micro and nanoparticles in relation to others / Uma das ?reas da nanotecnologia de grande interesse ? a da forma??o de nanopart?culas (nanoesferas e nanoc?psulas), pois permite o desenvolvimento de f?rmulas de libera??o controlada, ou seja, aquelas com a capacidade de liberar os agentes ativos adequadamente. Em tais produtos, o princ?pio ativo protegido ? liberado gradativamente por meio de est?mulos adequados. Existe um interesse especial na prepara??o de nanopart?culas de pol?meros biodegrad?veis, como por exemplo, os poli?steres como ?cido poli-l?ctico e o glic?lico, e seus copol?meros, como o ?cido poli(l?ctico-co-glic?lico) (PLGA), considerando sua biocompatibilidade e biodegrada??o. Neste contexto, o presente trabalho teve como objetivo produzir nanoesferas a partir do pol?mero biodegrad?vel PLGA contendo mentol atrav?s da t?cnica de emuls?o m?ltipla/evapora??o do solvente. As micro e nanoesferas de PLGA/mentol preparadas apresentaram, na sua maioria, di?metros m?dios entre 217 e 13.103 nm, Tg 41 ?C e estabilidade t?rmica at? 260 ?C. A presen?a de mentol nas micro e nanoesferas foi evidenciada atrav?s das t?cnicas de caracteriza??o utilizadas, bem como, pela presen?a f?sica de aroma caracter?stico de mentol percept?vel ao olfato. Por ?ltimo, foi feita uma avalia??o preliminar da efici?ncia de incorpora??o do aroma, mostrando-se eficaz, uma vez que, as micro e nanoesferas com maior concentra??o de mentol em sua formula??o demonstraram a partir das t?cnicas utilizadas (rela??o entre as alturas das bandas do mentol e de PLGA no IV e atrav?s da maior perda de massa relativa ao mentol no TGA), apresentarem aproximadamente 60% mais mentol incorporado a matriz polim?rica destas micro e nanopart?culas em rela??o ?s demais.

Made available in DSpace on 2015-04-14T13:59:04Z (GMT). No. of bitstreams: 1 454476.pdf: 17188672 bytes, checksum: b9bae5126e1fa699d075b37bc4ae70fa (MD5) Previous issue date: 2014-03-06 / Searches in nanotechnology allied to studies of biopolymers advances for application in the medical / pharmaceutical field. Micro / nanoparticles (NP) with biodegradable polymer systems are promising for the controlled release of drugs in the form of nanocapsules (NC) or nanospheres (NS), able to protect / release the substance gradually. This work aims to prepare NP polyurethane (Mw = 224,973 g/ mol and Mn = 134 670 g / mol) for the encapsulation by multiple emulsion of the pharmaco α-tocopherol (α-TOC) with and without a?ai oil and different stirring techniques (ultra-turrax (TR) and ultrasound (SM)), as well as the study of controlled release in physiological medium. The average sizes of the obtained NP were between 600 nm and 10 μm using the SM and between 2-15 μm using the TR and all presented spherical morphology and variables distributions depending on the presence or absence of a?ai oil. It was also possible to detect the presence of α-TOC and a?ai oil (when present) in all NP's, as well as the degradation of PU and release of α-TOC through the techniques of UV-Vis, IR and TGA. The encapsulation efficiency of α-TOC was moderate, ranging between 15-34% for NPs obtained by TR and between 18-44% for NPs obtained by SM, due to the affinity of the hydrophobic compound with the PU. The amount of α-TOC initially added in the formulations obtained high rates of recovery ranging from 93-96%. The NPs showed a mass loss of less than 4% when exposed to hydrolytic degradation up to 30 days. The ultraturrax samples without a?ai oil and ultrasound with a?ai oil showed increased release of α-TOC from the 12th day, whereas NP's ultra-turrax with a?ai oil and ultrasound without acai oil showed constant release up to day 30. The results indicate that the presence of oil using the MS showed more efficiency in the formation of NPs / Pesquisas em nanotecnologia aliada aos estudos dos biopol?meros possibilitaram avan?os para aplica??o na ?rea m?dica/farmac?utica. Sistemas de micro/nanopart?culas (NP) com pol?meros biodegrad?veis s?o promissores na libera??o controlada de f?rmacos na forma de nanoc?psulas (NC) ou de nanoesferas (NE), capaz de proteger/liberar a subst?ncia gradativamente. Este trabalho tem como objetivo preparar NP de poliuretano (PU- Mw= 224.973 g/mol e Mn=134.670 g/mol) para o encapsulamento por emuls?o m?ltipla do f?rmaco α-tocoferol (α-TOC) com e sem ?leo de a?a? e com diferentes t?cnicas de agita??o (ultra-turrax (TR) e ultrassom (SM) ), bem como, o estudo de libera??o controlada em meio fisiol?gico. Os tamanhos m?dios das NP obtidas foram entre 600nm e 10 μm utilizando o SM e entre 2-15 μm utilizando o TR e apresentaram morfologia esf?rica e distribui??es vari?veis em fun??o da presen?a ou n?o de ?leo de a?a?. Tamb?m foi poss?vel detectar a presen?a de α-TOC e ?leo de a?a? (quando presente) em todas as NP s, assim como a degrada??o do PU e libera??o do α-TOC atrav?s das t?cnicas de UVVis, TGA e IV. A efici?ncia de encapsulamento do α-TOC foi moderada, variando entre 15 a 34% para as NP s obtidas por TR e entre 18 a 44% para as NP s obtidas por SM, devido ? afinidade deste composto hidrof?bico pelo PU. A quantidade de α- TOC inicialmente adicionada nas formula??es obteve tamb?m elevadas taxas de recupera??o, variando entre 93-96%. As NP s apresentaram uma perda de massa abaixo de 4% quando expostos a degrada??o hidrol?tica at? 30 dias. As amostras TR S/?LEO e SM C/?LEO apresentaram libera??o crescente de α-TOC a partir do 12? dia, enquanto que as NP s TR C/?LEO e SM S/?LEO apresentaram libera??o constante ate 30? dia. Os resultados indicam que a presen?a de ?leo e utiliza??o de SM mostraram-se mais eficiente na forma??o das NP s.

Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-06-19T17:29:23Z No. of bitstreams: 1 TES_RAFAEL_COLOMBO_ABRUZZI_COMPLETO.pdf: 7264626 bytes, checksum: d911197d999f72ea82202fcb05b37bf4 (MD5) / Made available in DSpace on 2017-06-19T17:29:23Z (GMT). No. of bitstreams: 1 TES_RAFAEL_COLOMBO_ABRUZZI_COMPLETO.pdf: 7264626 bytes, checksum: d911197d999f72ea82202fcb05b37bf4 (MD5) Previous issue date: 2017-03-24 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Funda??o de Amparo ? Pesquisa do Estado do Rio Grande do Sul (FAPERGS) / Given that emissions control has become increasingly more rigorous, monitoring processes that require more precise and diversified information with regard to air pollution and toxic agents is inevitable. In the workplace, there is an increasing need for gas sensors with superior performance. Solid state sensors for gases are based on the fundamental principle that some metal oxide semiconductors such as SnO2 are very reactive on the surface where the analyte is adsorbed, changing the electric resistance of the oxide, which is in and of itself a reversible process, thus enabling the detection of gaseous species. This study presents test results obtained from the synthesis of nanostructured tin oxide by different methods until the production of the solid state sensor to monitor methane gas from coal mines. Zeolites were used to improve the selectivity of the sensor, as well as the validation of alternative flasks to collect gas samples. Regarding the characterization of SnO2, the analysis results of FESEM, TEM and XRD indicated nanometric structures. The gas adsorption tests on zeolite pellets showed that the zeolite 13X has a higher efficiency in adsorption of CO2 compared with other adsorbents, enabling its application as a filter for improving the selectivity of the sensor system. The AV_BR flasks were efficient when compared to commercial flasks for the collection and storage of CO, CO2 and CH4. The sensor was sensitive for CH4 at different concentrations and temperatures evaluated, mainly when doped with Pd (ER3B1 and ER3B2) and with smaller particle sizes (ER1A), as well as 13X pellets zeolite was efficient to make the sensor more selective to CH4 in the presence of CO2. / O controle de emiss?es de gases se torna cada vez mais rigoroso, ent?o um monitoramento de processos e informa??es mais precisas e diversificadas s?o exigidos no que se refere a polui??o do ar e agentes t?xicos. Em ambientes de trabalho, h? a necessidade cada vez maior de sensores de gases com desempenho superior. Os sensores de estado s?lido para gases se baseiam no princ?pio fundamental de que alguns ?xidos met?licos semicondutores, como o SnO2, s?o muito reativos na superf?cie, onde o analito adsorve, mudando a resist?ncia el?trica do ?xido, sendo este um processo revers?vel, possibilitando assim a detec??o de esp?cies gasosas. O presente trabalho apresenta resultados de testes realizados desde a s?ntese do ?xido de estanho nanoestruturado por diferentes m?todos at? a confec??o do sensor de estado s?lido para monitorar g?s metano oriundo de minas de carv?o f?ssil. Ze?litas foram utilizadas para melhorar a seletividade do sensor, assim como a valida??o de frascos alternativos para coleta de amostras de g?s. Quanto a caracteriza??o do SnO2, os resultados das an?lises de MEV-FEG, MET e DRX indicaram estruturas nanom?tricas. Os ensaios de adsor??o de g?s em pellets de ze?litas apontaram que a ze?lita 13X apresenta uma maior efici?ncia na adsor??o de CO2 quando comparada com outros adsorventes, o que possibilita sua aplica??o como filtro para melhorar a seletividade do sistema sensor. Os frascos FA_BR se mostraram eficientes quando comparados com frascos coletores comerciais, para coleta e estocagem de CO, CO2 e CH4. O sensor se mostrou sens?vel para CH4 nas diferentes concentra??es e temperaturas avaliadas principalmente quando dopado com Pd (ER3B1 e ER3B2) e com menores tamanhos de part?culas (ER1A), assim como a ze?lita 13X em pellets se mostrou eficiente para tornar o sensor mais seletivo ao CH4 na presen?a de CO2.

Submitted by PPG Medicina e Ci?ncias da Sa?de (medicina-pg@pucrs.br) on 2017-12-26T13:35:05Z No. of bitstreams: 1 GIOVANNA_MEDEIROS_TAVARES_DE_OLIVEIRA_TES.pdf: 3690052 bytes, checksum: e6e9b4fea2305637782a214e8f45af2d (MD5) / Approved for entry into archive by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-12-29T10:45:02Z (GMT) No. of bitstreams: 1 GIOVANNA_MEDEIROS_TAVARES_DE_OLIVEIRA_TES.pdf: 3690052 bytes, checksum: e6e9b4fea2305637782a214e8f45af2d (MD5) / Made available in DSpace on 2017-12-29T10:47:48Z (GMT). No. of bitstreams: 1 GIOVANNA_MEDEIROS_TAVARES_DE_OLIVEIRA_TES.pdf: 3690052 bytes, checksum: e6e9b4fea2305637782a214e8f45af2d (MD5) Previous issue date: 2017-08-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Initially used in magnetic resonance imaging in the late 1970s, iron oxide nanoparticles (IONPs) have wide application in the medical field today, in diagnostics, drug delivery, cellular therapies and theragnostic. The high biocompatibility, small size, functionalization and ability to respond to an applied magnetic field gives this nanoparticle great advantage over other nanomaterials. Studies have demonstrated the low toxicity and high applicability of this nanomaterial in the clinic, however some questions remain unanswered. When in contact with the in vivo metabolism, nanomaterials can behave in a way to degrade their coating and release the ions contained in their nucleus. In fact, side effects related to exposure to IONPs are mainly related to the release of its elemental nucleus; which, when endocyted, can be degraded inside the lysosomes and release [Fe] ions. Changes in iron homeostasis can be very damaging to the cell, causing inflammation, lipid peroxidation, and oxidative stress. Organs more sensitive to iron accumulation, such as the heart, may demonstrate apoptosis and tissue degeneration. Such toxic effects are easily detected in studies using zebrafish as an animal model. Protocols with zebrafish embryos for toxicological analysis have the advantage of allowing large-scale screening on development, survival, behavior, gene expression and cardiotoxicity. Under this scenario, this thesis aims to evaluate the toxicity of commertial and "in house" synthesis of Iron Oxide Nanoparticles in zebrafish. Behavioral analysis of locomotion and gene expression of zebrafish larvae exposed to uncoated and dextran-coated iron oxide nanoparticles indicated a toxicity at low concentrations of nanoparticle exposure, contrary to what is reported in the literature. In addition, changes in the apoptotic pathway suggest that this route is closely linked to the behavioral effects found. Subsequent analyzes, targeting cardiotoxicity, suggested that concentrations above 100 ?g/ml are damaging for the heart. Molecular analyzes in the groups exposed to the iron oxide nanoparticle and to iron solution helped to establish a parallel between the toxicity of these nanoparticles and the pathways of iron metabolism. / Inicialmente utilizadas em exames de resson?ncia magn?tica no final dos anos 1970 as nanopart?culas de ?xido de ferro (IONPs) possuem hoje vasta aplica??o na ?rea m?dica, em exames de diagn?stico, sistema de envio de drogas, terapias celulares e como agente teragn?stico. Sua alta biocompatibilidade, pequeno tamanho, facilidade de manipula??o e capacidade de responder a aplica??o externa de campo magn?tico lhe oferece grande vantagem sobre outros nanomaterias. Estudos vem demostrando a baixa toxicidade e alta aplicabilidade deste nanomaterial na cl?nica, entretanto algumas quest?es ainda se encontram sem resposta. Quando em contato com o metabolismo in vivo, nanomateriais podem se comportar de forma a degradar sua estrtutura externa e liberar os ?oins contidos no seu n?cleo. De fato, efeitos adversos relacionado a exposi??o a IONPs est?o majoritariamente relacionadas a libera??o do seu n?cleo elementar; que, quando endocitado, pode ser degradado nos lisossomos e liberar ?ons [Fe]. Altera??es na homeostase de ferro podem ser muito prejudiciais ? c?lula, causando inflama??o, peroxida??o lip?dica e estresse oxidativo. ?rg?os mais sens?veis ao ac?mulo do ferro, como o cora??o, podem apresentar apoptose e degenera??o tecidual. Tais efeitos t?xicos s?o facilmente detectados em estudos utilizando zebrafish como animal modelo. Protocolos com embri?es de zebrafish para an?lise toxicol?gica possuem a vantagem de permitir estudos em grande escala de efeitos no desenvolvimento, sobreviv?ncia, comportamento, express?o g?nica e cardiotoxicidade. Sob esse cen?rio, esta tese tem como objetivo avaliar a toxicidade de Nanopart?culas de Oxido de Ferro (IONPs) de s?ntese pr?pria e comerciais no modelo experimental zebrafish. An?lise comportamental de locomo??o e express?o g?nica de larvas de zebrafish expostas a Nanopart?culas de ?xido de Ferro puras (sem envolt?rio) e revestidas com dextran indicou uma toxicidade em baixas concentra??es de exposi??o ? nanopart?culas, contrario ao que ? relatado na literatura. Al?m disso, altera??es na via apopt?tica sugere que esta rota esteja intimamente ligada aos efeitos comportamentais encontrados. An?lises posteriores, direcionadas ? cardiotoxicidade sugerem efeitos t?xicos acima de 100 ?g/mL. An?lises gen?mica de express?o nos grupos expostos ? nanopart?cula de ?xido de ferro e ? solu??o de ferro met?lico (usado como controle de positivo de excesso de ferro) permitiram a identifica??o de um paralelo entre toxicidade destas nanopart?culas e as vias de metaboliza??o do ferro.

Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2016-12-06T16:25:03Z No. of bitstreams: 1 TES_MARTIMIANO_KRUSCIEL_DE_MORAES_COMPLETO.pdf: 7476914 bytes, checksum: 8586f15be948bcd9e54e218b50a389ef (MD5) / Made available in DSpace on 2016-12-06T16:25:03Z (GMT). No. of bitstreams: 1 TES_MARTIMIANO_KRUSCIEL_DE_MORAES_COMPLETO.pdf: 7476914 bytes, checksum: 8586f15be948bcd9e54e218b50a389ef (MD5) Previous issue date: 2016-08-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Funda??o de Amparo ? Pesquisa do Estado do Rio Grande do Sul (FAPERGS) / Carbon capture and storage in geological formations is a promising technology to mitigate emissions of the main greenhouse gas, CO2. However, its application involves maintaining the integrity of the materials used in the injection wells to prevent leakage of CO2. On the other hand, advances in nanotechnology research have contributed to improve the performance of cementitious materials. In this context, this work investigate the influence of the incorporation of clay (organomodified montmorillonite- OMMT) and silica nanoparticles in the class G cement paste used in the completion and abandonment of oil wells in two reaction media, wet supercritical CO2 and water saturated with CO2, at high pressure (15 MPa) and high temperature (90 ?C) for 7, 21 and 56 days. The techniques of field emission gun scanning electron microscopy (FEG/SEM), X ray diffraction (XRD), Vickers hardness and compressive strength were used to evaluate the effect of degradation on the structure and mechanical properties of the cement paste. In general, the inclusion of nanoparticles promoted an increase in chemically altered layer, with the exception of adding 0.5% OMMT, which can be an indication that there is an adequate amount of nanoparticles that can produce an increasing on the resistance to chemical degradation in the presence of CO2. However, in general, the results indicate an improvement on mechanical properties with the addition of nanoparticles, compared with the cement paste without addiction of nanoparticles. Among all types and concentrations of nanoparticles studied, the best results in terms of density and resistance to degradation by CO2 was obtained for the content of 0.5% OMMT. / A captura e armazenamento de carbono em forma??es geol?gicas ? uma tecnologia promissora para mitiga??o das emiss?es do principal g?s de efeito estufa, o CO2. Entretanto, sua aplica??o envolve manter a integridade por longos per?odos de tempo dos materiais empregados nos po?os de inje??o para evitar vazamento de CO2. Por outro lado, o avan?o nas pesquisas em nanotecnologia tem contribu?do para a melhoria do desempenho de materiais ciment?cios. Neste contexto, este trabalho investiga a influ?ncia da incorpora??o de nanopart?culas de argila (montmorilonita organof?lica- OMMT) e s?lica nas propriedades da pasta de cimento classe G empregada na completa??o e abandono de po?os de petr?leo, em dois meios reacionais, CO2 supercr?tico ?mido e ?gua saturada com CO2, a alta press?o (15 MPa) e temperatura (90 ?C), durante 7, 21 e 56 dias. As t?cnicas de microscopia eletr?nica de varredura por emiss?o de campo (FEG/MEV), difra??o de raios X (DRX), microdureza Vickers e resist?ncia ? compress?o foram utilizadas para avaliar o efeito da degrada??o na estrutura e propriedades mec?nicas da pasta de cimento. De modo geral, a inclus?o de nanopart?culas promoveu um aumento da camada alterada quimicamente, com exce??o da adi??o de 0,5% de OMMT, o que ? um indicativo de que h? um teor adequado de nanopart?culas que pode aumentar a resist?ncia ? degrada??o qu?mica em presen?a de CO2. Contudo, de um modo geral, observou-se uma melhora nas propriedades mec?nicas com a adi??o de nanopart?culas, se comparado com a pasta de cimento padr?o. Dentre os tipos e teores de nanopart?culas testados, os melhores resultados em termos de densidade da pasta endurecida e resist?ncia ? degrada??o por CO2 foram obtidos para o teor de 0,5% de OMMT.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-20T21:12:47Z No. of bitstreams: 1 MonicaDeOliveiraRochaAmorim_DISSERT.pdf: 1554706 bytes, checksum: 76ac024cb167786309761c3cbfd2fe87 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-02-22T23:59:38Z (GMT) No. of bitstreams: 1 MonicaDeOliveiraRochaAmorim_DISSERT.pdf: 1554706 bytes, checksum: 76ac024cb167786309761c3cbfd2fe87 (MD5) / Made available in DSpace on 2017-02-22T23:59:38Z (GMT). No. of bitstreams: 1 MonicaDeOliveiraRochaAmorim_DISSERT.pdf: 1554706 bytes, checksum: 76ac024cb167786309761c3cbfd2fe87 (MD5) Previous issue date: 2016-09-30 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O estado do Rio Grande do Norte possui uma grande diversidade de esp?cies de macroalgas marinhas fornecedores de compostos com grande potencial farmacol?gico e biotecnol?gico. Dentre eles destacam-se os polissacar?deos sulfatados. Polissacar?deos que cont?mL-fucose sulfatada s?o muitas vezes denominados de fucanas. A alga marrom Spatoglossumschr?ederi sintetiza tr?s fucanas e aquela que ? obtida em maior quantidadefoi denominada de fucana A. A produ??o de nanopart?culas de prata contendo biopol?meros naturais tem sido apontada como uma excelente alternativa para potencializar ou fornecer novas aplicabilidades aos mesmos, pois estes apresentam propriedades farmacol?gicas que podem ser potencializadas se aliadas ? nanotecnologia. A fucana A n?o se mostroucitot?xica para diferentes linhagens de c?lulas normais, nem tampouco ? t?xico para ratos quando administrado em altas doses. Ademais, apresentou baixa toxicidade para c?lulas tumorais. Com intuito de potencializar a toxicidade da fucana Afrente ?s linhagens tumorais, nanopart?culas de prata contendo este polissacar?deo foram sintetizadas por um m?todo verde (pouco agressivo ao meio ambiente). Estas nanopart?culas apresentaram um tamanho m?dio de 210 nm e formato arredondado, bem como,uma carga superficial negativa e foram est?veis por quatorze meses. Quando incubadas com c?lulas, estas nanopart?culas n?o apresentaram citotoxicidade para diferentes linhagens de c?lulas normais, mas diminu?ram a viabilidade de v?rias linhagens de c?lulas tumorais (786-0, HepG2, Siha), principalmente c?lulas de adenocarcinoma de renal 786-0. An?lises por fluoresc?ncia e de citometria de fluxo sugerem que as nanopart?culas induzem necrose nas c?lulas 786-0. Por outro lado, as nanoparticulas n?o foram toxicas para c?lulas renais normais (HEK, VERO, MDCK). Os dados aqui mostrados levam a conclus?o de que as nanopart?culas com fucana A s?o promissores agentes para combate de adenocarcinoma renal.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-01-24T12:09:54Z No. of bitstreams: 1 SilasSarmentoPedrosa_TESE.pdf: 13307553 bytes, checksum: 616db20e12e34747afe3ca24c303b31a (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-01-26T12:09:55Z (GMT) No. of bitstreams: 1 SilasSarmentoPedrosa_TESE.pdf: 13307553 bytes, checksum: 616db20e12e34747afe3ca24c303b31a (MD5) / Made available in DSpace on 2018-01-26T12:09:55Z (GMT). No. of bitstreams: 1 SilasSarmentoPedrosa_TESE.pdf: 13307553 bytes, checksum: 616db20e12e34747afe3ca24c303b31a (MD5) Previous issue date: 2017-09-15 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / H? presentemente grande interesse de pesquisa em aglomerados de nanopart?culas superparamagn?ticas, devido em parte ? alta demanda para aplica??es biom?dicas, e ao mesmo tempo ao grande interesse, do ponto de vista fundamental, em novas fases magn?ticas. A suscetibilidade magn?tica inicial e o campo de fuga, s?o fatores essenciais para otimiza??o de sistemas para aplica??es biom?dicas. H?, ao mesmo tempo, grande interesse em confirmar a exist?ncia de ferromagnetismo dipolar, em sistemas onde a energia de troca n?o ? fator dominante. Desenvolvemos um estudo te?rico do impacto da intera??o dipolar sobre as fases magn?ticas de nanopart?culas superparamagn?ticas, confinadas em aglomerados esf?ricos e elipsoidais. Consideramos nanopart?culas de Fe3O4 com tamanhos no intervalo de 9 nm a 12 nm, arranjadas com densidade uniforme em aglomerados de tamanho da ordem de centenas de nan?metros. Mostramos que as fases magn?ticas, e a suscetibilidade inicial, s?o controladas pela intera??o dipolar, e que a topologia do arranjo de nanopart?culas, o tamanho das nanopart?culas e a densidade de empacotamento s?o fatores que controlam as propriedades magn?ticas. Mostramos que a intera??o dipolar pode estabilizar fases magn?ticas cl?ssicas, conhecidas apenas para sistemas com alto conte?do de energia de troca e de anisotropia. Al?m disso, as fases magn?ticas em reman?ncia t?m uma caracter?stica peculiar: a m?dia t?rmica do momento de cada nanopart?cula pode se aproximar do valor de satura??o, mantendo o aglomerado superparamagn?tico. Aglomerados elipsoidais de alta excentricidade s?o os sistemas de escolha para aplica??es biom?dicas porque podem exibir expressivo aumento de suscetibilidade magn?tica, mantendo um campo de fuga de baixa intensidade em reman?ncia. O modelo te?rico reproduz satisfatoriamente resultados experimentais de aglomerados esf?ricos de Fe3O4, e de sistemas de part?culas de Fe e Co de baixa dimensionalidade. / Superparamagnetic nanoparticles clusters are currently driving considerable research attention. The interest stems from chances of designing systems with promising potential for technological applications, and from the fundamental viewpoint, tailoring new magnetic phases. The initial magnetic susceptibility and the stray field, at remanence, are key features for the optimization of magnetic systems for biomedical applications. Also, the existence of dipolar ferromagnetism, in the absence of exchange energy, has been one of the focus of magnetism for decades. We report a theoretical discussion of the impact of the dipolar interactions on the magnetic phases of superparamagnetic nanoparticles confined in spherical and ellipsoidal clusters. We consider Fe3O4 nanoparticles, with size ranging from 9 nm to 12 nm, arranged with uniform density in hundreds nanometer size volumes. We show that the magnetic phases, and the initial susceptibility, are controlled by the dipolar interaction. Also, the topological nanoparticle arrangement, the nanoparticle size, and the packing density, are key features. We show that the dipolar interaction alone may stabilize classical magnetic phases, well known for systems with large content of exchange and anisotropy energies. In addition, we have found that at remanence the nanoparticles clusters magnetic phase have a unique property. The dipolar energy leads to thermal stabilization of the individual nanoparticles moments. Large nanoparticles densities may allow nearly full thermal value of the nanoparticles magnetic moments. Despite this, the nanoparticles cluster is superparamagnetic, with a rather small stray field at remanence, as required for biomedical safety. Nanoparticle clustering in large eccentricity ellipsoidal volumes are promising systems for both low field and large field biomedical applications. For low field applications, there is a large increase in the initial susceptibility, with enhancement in the efficacy of vector targeting and also for hyperthermia absorption rate. For high field applications, the enhancement of the stray is much stronger than that for spherical clusters. Our theoretical model reproduces typical properties of Fe3O4 nanoparticles spherical clusters, as well as intriguing results for Fe and Co quasi-one-dimensional systems.

Made available in DSpace on 2015-04-14T13:58:54Z (GMT). No. of bitstreams: 1 442327.pdf: 1822421 bytes, checksum: 8245c1989efe77ad16c8f717de01179d (MD5) Previous issue date: 2012-08-24 / In this study we investigated the synthesis and characterization (morphological structural and magnetic) of iron oxide nanoparticles coated with dextran and functionalized with amino groups, which are useful as contrast agents for magnetic resonance imaging. For the synthesis we used the method of co-precipitation of Fe (III) and Fe (II) with ammonium hydroxide. Three batches of samples were synthesized under identical conditions. The analysis of samples from each batch revealed some differences in the stability against agglomeration and iron concentrations (ranging from 10 to 8 mg / mL). A narrow size distribution of the nanoparticles was observed by DLS (Dynamic Light Scattering) in all cases with a mean hydrodynamic diameter of about 10 nm. The mean particle size was confirmed by TEM (Transmission Electron Microscopy), images. Elemental analysis by Rutherford Backscattering Spectrometry (RBS) and Energy Dispersive Spectroscopy (EDS) revealed a structure compatible with iron oxide, and a thermal decomposition pattern dominated by the polymer coating of the particles. The magnetic properties of the particles were confirmed by Alternating Gradient Force Magnetometer (AGFM) whit reveals a vanishing hysteresis loop. Measurements of the magnetic nuclear relaxivity were performed directly in a magnetic resonance imaging (MRI) equipment Whit an MRI phantom containing samples with different concentrations of the FeNP. The study of magnetic relaxation with test objects indicated a clear effect of the FeNP or the MRI signal through the decreases and T1 and T2 in aqueous solutions. Measured relaxivities obtaining from the curves of the relaxation rate versus FeNP concentration were between 41 and 24 mM-1s-1 for r2 and 2,0 to 1,7 mM-1s-1 for r1. We conclude that the method applied in the synthesis of the FeNP was be very efficient in producing NPs with suitable properties for use as a contrast agent in MRI images / Nesse trabalho investigou-se a s?ntese e caracteriza??o morfol?gica, estrutural e magn?tica de nanopart?culas de ?xido de ferro, recobertas com dextran e funcionalizadas com grupos amina, ?teis como uma plataforma de agentes de contraste para imageamento por resson?ncia magn?tica. Para a s?ntese, foi usado o m?todo de coprecipitac?o do Fe (III) e Fe (II) com hidr?xido de am?nio. Foram sintetizados tr?s lotes de amostras. A an?lise de amostras de cada um dos lotes revelou algumas diferen?as quanto ? estabilidade frente a aglomera??o e a concentra??o de ferro (variando de 8 -10 mg/mL). Foi observado por Espalhamento de Luz Din?mico uma distribui??o estreita de tamanho das nanopart?culas em todos os casos, com um di?metro hidrodin?mico m?dio em torno de 5-8 nm, confirmados pelas imagens de TEM (Microscopia Eletr?nica de Transmiss?o). Atrav?s de an?lise de Espectroscopia de Energia Dispersiva (EDS) e Retroespalhamento Rutherford (RBS) obtivemos uma distribui??o elementar compat?vel com a do ?xido de ferro, e padr?o de decomposi??o t?rmico dominado pelo recobrimento polim?rico demonstrado nas curvas do an?lise termogravim?trica (TGA). Curvas de magnetiza??o obtidas por um Magnet?metro de Gradiente de for?a Alternada (AGFM) confirmaram a caracter?stica magn?tica das part?culas e aus?ncia de histerese. Medidas de relaxividade magn?tica nuclear foram feitas diretamente num equipamento de imagens por resson?ncia magn?tica (MRI) atrav?s de um phantom contendo amostras com diferentes concentra??es das nanopart?culas de ?xido de ferro (FeNP). O estudo da relaxa??o magn?tica em objetos teste indicou um efeito claro de perturba??o do sinal pelas part?culas, com diminui??es do tempo de relaxa??o longitudinal (T1) e do tempo de relaxa??o transversal (T2) em solu??es aquosas, confirmando a obten??o do efeito de contraste desejado, com relaxividades que variaram entre 41 e 24 mM-1s-1 para relaxividade (r2) e 2,0 a 1,7 mM-1s-1 para a relaxividade (r1). Conclu?mos que, o m?todo qu?mico por coprecipita??o de Fe(II) e Fe(III) utilizado na s?ntese de nanopart?culas magn?ticas mostrou-se apropriado para produzir nanopart?culas (NPs) com propriedades adequadas para uso como agente de contraste em imagens por MRI

Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-09-22T17:48:51Z No. of bitstreams: 1 TES_RODRIGO_SCOPEL_COMPLETO.pdf: 15566888 bytes, checksum: 14d33da014482ed0a63266b36e2baee6 (MD5) / Approved for entry into archive by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-09-22T17:49:44Z (GMT) No. of bitstreams: 1 TES_RODRIGO_SCOPEL_COMPLETO.pdf: 15566888 bytes, checksum: 14d33da014482ed0a63266b36e2baee6 (MD5) / Made available in DSpace on 2017-09-22T17:49:54Z (GMT). No. of bitstreams: 1 TES_RODRIGO_SCOPEL_COMPLETO.pdf: 15566888 bytes, checksum: 14d33da014482ed0a63266b36e2baee6 (MD5) Previous issue date: 2017-03-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Human skin is an attractive option for applying active compounds that minimize adverse effects due to low systemic exposure when compared with other routes of administration. These compounds can permeate the skin layer by the intercellular, intracellular and follicular routes resulting in a topical and/or transdermal delivery. The delivery of active compounds via nanotechnology-based systems may revolutionize the treatment of several disorders including the ones related with the skin. Among these systems, liposomes, and biocompatible and bioabsorbable polymeric nanoparticles, are the technologies with the greatest growth in the field. Therefore, it is ideal to look for mechanisms that couple the mechanical advantages of polymeric nanoparticles with the biomimetic characteristics of liposomes. The aim of this work is to study the synthesis and behavior of hybrid nanoparticles comprising a polymeric core (PLGA) coated by a mixture of lipids (HSPC:CHOL:DSPE-PEG) functionalized to ligand molecules. Initially, it is proposed the conjugation of vitamin D on the surface of the hybrid nanoparticles to target them for specific receptors (VDR) present on melanocytes and melanoma cells. Subsequently, the synthesis of a RGD peptide is carried out aiming to verify the possibility of applying the same methodology for targeting more specific receptors of these cells. Seeking a greater understanding about how the drug is released from these nanoparticles, in vitro experiments of drug release are conducted. In addition, an explicit analytical solution of the mathematical model proposed by Baker-Lonsdale is proposed in order to obtain information regarding the transport phenomena that controls the drug release. Finally, it is proposed a skin permeation mathematical model with boundary conditions adapted for the target nanoparticles. / A pele ? uma rota de entrega atrativa para a aplica??o de f?rmacos que minimiza efeitos adversos devido ? baixa exposi??o sist?mica quando comparada a outras vias de aplica??o. Estes compostos podem permear a camada pelas rotas intercelular, intracelular e transap?ndice resultando em uma entrega t?pica e/ou transd?rmica. A entrega de compostos atrav?s de sistemas baseados na nanotecnologia pode revolucionar o tratamento de diversas doen?as e disfun??es onde, entre estes sistemas de libera??o, lipossomas e nanopart?culas polim?ricas biocompat?veis, s?o as tecnologias que apresentam maior crescimento. A partir disso, torna-se ideal a pesquisa de mecanismos que contemplem as vantagens mec?nicas das nanopart?culas polim?ricas com as caracter?sticas biomim?ticas dos lipossomas. O objetivo deste trabalho ? estudar a s?ntese e comportamento frente ? aplica??o t?pica de nanopart?culas h?bridas compostas por um n?cleo de PLGA e revestidas com uma mistura de fosfolip?dios (HSPC:COL:DSPE-PEG) funcionalizada com mol?culas ligantes. Inicialmente, prop?e-se a conjuga??o de vitamina D na superf?cie das nanopart?culas h?bridas com o objetivo de direcionar as mesmas para receptores espec?ficos de vitamina D (VDR) presentes em melan?citos e c?lulas de melanoma. Em sequ?ncia, a s?ntese do pept?deo RGD ? realizada verificando a aplicabilidade da metodologia para um futuro direcionamento a receptores mais espec?ficos presentes nestas c?lulas. Visando um maior entendimento sobre o comportamento de libera??o de f?rmacos a partir destas nanopart?culas, testes in vitro de libera??o s?o conduzidos. Al?m disso, ? sugerida uma solu??o anal?tica expl?cita do modelo matem?tico de libera??o proposto por Baker-Lonsdale com o objetivo de obter informa??es referentes ao fen?meno de transporte controlador do processo de libera??o de f?rmacos. Por fim, prop?e-se um modelo matem?tico de permea??o cut?nea com condi??es de contorno adequadas para estes nanocarreadores.

Submitted by PPG Odontologia (odontologia-pg@pucrs.br) on 2018-03-15T18:05:08Z No. of bitstreams: 1 LEONARDO_DE_CESERO_TES.pdf: 930355 bytes, checksum: 2c97f9568abe8fdc237aa889661c8a3c (MD5) / Approved for entry into archive by Tatiana Lopes (tatiana.lopes@pucrs.br) on 2018-03-27T12:23:49Z (GMT) No. of bitstreams: 1 LEONARDO_DE_CESERO_TES.pdf: 930355 bytes, checksum: 2c97f9568abe8fdc237aa889661c8a3c (MD5) / Made available in DSpace on 2018-03-27T12:27:51Z (GMT). No. of bitstreams: 1 LEONARDO_DE_CESERO_TES.pdf: 930355 bytes, checksum: 2c97f9568abe8fdc237aa889661c8a3c (MD5) Previous issue date: 2017-11-24 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq / The current applications of nanotechnology in dentistry include adhesive systems and composite resins, but they are still quite limited in dental materials. Dental stone is a widely used material, and the incorporation of silica nanoparticles is still unexplored. The purpose of this study is to evaluate the behavior of the mechanical properties of dental stones with the addition of silica nanoparticles at different concentrations. A total of 180 samples were prepared, 90 for each dental stone (Durone and Fuji Rock). For the control group (CG), no silica particles were added, while test group 1 (TG1) had silica nanoparticles added to 1% by weight, and test group 2 (TG2) had silica nanoparticles added to 5% by weight. The roughness, diametral tensile strength (DTS) and compressive strength were measured 24 hours after the start of spatulation. The mean roughness values for Durone were CG= 0,55, TG1= 0,36 and TG2= 0,28 ?m and for Fuji Rock were CG= 0,47, TG1= 0,31 and TG2= 0,35 ?m. The mean DTS values for Durone were CG= 6,03, TG1= 5,17 and TG2= 5,02 MPa and for Fuji Rock were CG= 6,41, TG1= 5,23 and TG2= 4,56 MPa. The mean compressive strength values for Durone were CG= 35,44, TG1= 32,70 and TG2= 32,44 MPa and for Fuji Rock were CG= 42,97, TG1= 31,22 and TG2= 29,86 MPa. Surface roughness was statistically lower for the Durone and Fuji Rock stones (p< 0,001) when silica nanoparticles were added. For DTS and compressive strength, the addition of silica nanoparticles did not lead to statistically better results when compared to the control groups (p> 0,05). / A nanotecnologia na Odontologia est? presente nos sistemas adesivos e nas resinas compostas, sendo sua aplica??o ainda bastante limitada nos materiais dent?rios. O gesso odontol?gico ? um material amplamente utilizado e a incorpora??o de nanopart?culas de s?lica ? desconhecida. O objetivo do estudo ? avaliar o comportamento das propriedades mec?nicas dos gessos odontol?gicos a partir da adi??o de nanopart?culas de s?lica em diferentes concentra??es. Foram confeccionadas 180 amostras, sendo 90 para cada gesso (Durone e Fuji Rock). No grupo controle (GC) n?o foram adicionadas part?culas, no grupo teste 1 (GT1) foram adicionadas 1% em peso e o grupo teste 2 (GT2) recebeu 5% em peso de nanopart?culas de s?lica. Os testes de rugosidade, tra??o diametral (DTS) e compress?o foram realizados ap?s 24 horas do in?cio da espatula??o. Os valores m?dios de rugosidade para o Durone foram de GC= 0,55, GT1= 0,36 e GT2= 0,28 ?m e para o Fuji Rock foram de GC= 0,47, GT1= 0,31 e GT2= 0,35 ?m. Para DTS foram de GC= 6,03, GT1= 5,17 e GT2= 5,02 MPa para o Durone e para o Fuji Rock foram de GC= 6,41, GT1= 5,23 e GT2= 4,56 MPa. Para compress?o foram de GC= 35,44, GT1= 32,70 e GT2= 32,44 MPa para o Durone e para o Fuji Rock foram de GC= 42,97, GT1= 31,22 e GT2= 29,86 MPa. Houve uma menor rugosidade superficial estatisticamente para os gessos Durone e Fuji Rock (p< 0,001) quando adicionadas nanopart?culas de s?lica. Para a DTS e compress?o n?o houve estatisticamente resultados melhores quando adicionadas nanopart?culas de s?lica em compara??o aos grupos controles (p> 0,05).