?rea de concentra??o: Odontopediatria. / Submitted by Nivaldo Melo (nivaldo.melo@ufvjm.edu.br) on 2015-11-16T16:57:42Z No. of bitstreams: 2 ana_clara_sa_pinto.pdf: 998607 bytes, checksum: b17518e3d148cf4bd704371c7260c785 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-11-16T17:02:03Z (GMT) No. of bitstreams: 2 ana_clara_sa_pinto.pdf: 998607 bytes, checksum: b17518e3d148cf4bd704371c7260c785 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Made available in DSpace on 2015-11-16T17:02:03Z (GMT). No. of bitstreams: 2 ana_clara_sa_pinto.pdf: 998607 bytes, checksum: b17518e3d148cf4bd704371c7260c785 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Previous issue date: 2015 / Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O Tratamento Restaurador Atraum?tico (ART) ? uma t?cnica minimamente invasiva na qual remove-se somente o tecido cariado necrosado, utilizando-se instrumentos manuais. O Cimento de Ion?mero de Vidro (CIV) ? o material eleito para selar as cavidades na t?cnica do ART devido ?s suas propriedades f?sicas, qu?micas e biol?gicas favor?veis. O objetivo do presente estudo foi comparar a performance cl?nica do Cimento de Ion?mero de Vidro (CIV) de alta viscosidade (Ketac Molar Easymix?3M? ESPE, Seefeld, Germany) com um CIV convencional de baixa viscosidade (Vidrion R?SS White, Rio de Janeiro, RJ, Brasil) acrescido de nanocristais de celulose (NC)- (CIVNC) em cavidades classe I de molares dec?duos usando a t?cnica do Tratamento Restaurador Atraum?tico (ART). Sessenta crian?as de 4 a 7 anos de idade, residentes na cidade de Diamantina- Minas Gerais, que apresentaram no m?nimo dois molares dec?duos com les?es de c?rie classe I em dentina foram inclu?das. Um ensaio cl?nico randomizado duplo cego foi realizado no qual os dois materiais (Ketac Molar e CIVNC) foram aleatoriamente inseridos nas cavidades, ap?s sorteios do dente a ser restaurado e do material a ser utilizado. A performance cl?nica das restaura??es foi avaliada ap?s 3 meses usando o crit?rio de Frencken. Considerou-se insucesso de uma restaura??o quando a mesma apresentava defeito marginal ?0,5 mm, desgaste gradual >0,5 mm, quando a restaura??o foi perdida ou substitu?da por outra e a extra??o do dente. A an?lise de sobrevida das restaura??es foi feita usando o teste Qui-quadrado com tend?ncia linear. Adotou-se o valor de p<0,05 como significativamente estat?stico. A taxa de sobrevida das restaura??es para o Ketac Molar foi de 96,7% e para o CIVNC 94,7%. Uma diferen?a estatisticamente significativa (p=0,034) foi observada entre os dois cimentos em rela??o ? presen?a de defeitos marginais menores que 0,5 mm encontrados em 18,3% dos dentes tratados com CIVNC e em 6,5% das restaura??es realizadas com Ketac Molar. A performance cl?nica de ambos os cimentos de ion?mero de vidro foi satisfat?ria ap?s tr?s meses. A maior diferen?a entre os dois materiais foi observada em defeitos marginais menores que 0,5 mm. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Odontologia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2015. / ABSTRACT Atraumatic Restorative Treatment (ART) is a minimally invasive technique that involves only the removal of necrotic dentin, using manual instruments. The glass ionomer cement (GIC) is the material chosen to seal the cavities at the ART approach due to their physical, chemical and biological favorable properties. The aim of this study was to compare the clinical performance of a high viscosity glass ionomer cement (GIC) (Ketac Molar Easymix/3M? ESPE, Seefeld, Germany) with a conventional low viscosity GIC (Vidrion R?SS White River de Janeiro, RJ, Brazil) added cellulose nanocrystals (NC)- (GICCN) in class I cavities of primary molars using the Atraumatic Restorative Treatment (ART) technique. Sixty children aged 4-7 years, residents in the city of Diamantina-Minas Gerais, who had at least two primary molars with carious lesions class I in dentin were included. A randomized double-blind clinical trial was conducted and the two materials (Ketac Molar and GICCN) were randomly inserted into the cavities, after raffles of the tooth to be restored and the material to be used. The clinical performance of the restorations was evaluated after 3 months using the criteria of Frencken. It was considered failure of a restoration when it presented a marginal defect ?0.5 mm, gradual wear >0.5 mm, when the restoration was lost or replaced by another treatment and the tooth extraction. Restorations survival analysis were made using the Chi-square test with linear trend. The value of p<0.05 was adopted as statistically significant. The survival rate of restorations for Ketac Molar was 96.7% and 94.7% for the GICCN. A statistically significant difference (p=0.034) was observed between the two cements in relation to the presence of marginal defects lower than 0.5 mm found in 18.3% of the treated teeth with the modified cement (GICCN) and in 6.5% of the restorations with Ketac Molar. The clinical performance of both glass ionomer cements was satisfactory after three months. Increased difference between the two materials was observed on marginal defects lower than 0.5 mm.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-11-18T12:11:41Z No. of bitstreams: 1 WellingtonCantanhedeDosSantos_DISSERT.pdf: 28481348 bytes, checksum: 2d5163f73607a4e015bf9536232e933b (MD5) / Approved for entry into archive by Elisangela Moura (lilaalves@gmail.com) on 2015-11-18T15:01:11Z (GMT) No. of bitstreams: 1 WellingtonCantanhedeDosSantos_DISSERT.pdf: 28481348 bytes, checksum: 2d5163f73607a4e015bf9536232e933b (MD5) / Made available in DSpace on 2015-11-18T15:01:11Z (GMT). No. of bitstreams: 1 WellingtonCantanhedeDosSantos_DISSERT.pdf: 28481348 bytes, checksum: 2d5163f73607a4e015bf9536232e933b (MD5) Previous issue date: 2014-03-14 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / No presente trabalho foram sintetizados comp?sitos, a partir da moagem de altaenergia dos precursores hidroxiapatita - HAp (Ca10(PO4)6(OH)2) e ferro met?lico (?-Fe),com o intuito de serem utilizados em hipertermia magn?tica no tratamento do c?ncer. Osprodutos da moagem foram caracterizados por difratometria de raios X (DRX),microscopia eletr?nica de varredura (MEV), espectroscopia de energia dispersiva (EDS),medidas de magnetiza??o em fun??o do campo aplicado e medidas de temperatura emfun??o do campo alternado. Os DRX das amostras batidas de HAp/Fe revelaram somente apresen?a dos precursores. O MEV mostrou aglomerados com formatos irregulares. Ascurvas de magnetiza??o obtidas apresentam casos t?picos de comportamentoferromagn?tico fraco. Para as amostras batidas e submetidas a tratamento t?rmico asseguintes fases foram identificadas: HAp (Ca10(PO4)6(OH)2) , hematita (Fe2O3) e ferrofosfato tric?lcio, FeTCP, Ca19Fe2 (PO4)14. Analisando os resultados de M x H, verificou-seuma redu??o na magnetiza??o de satura??o, tendo em vista que o Fe foi incorporado ?HAp. As curvas de histerese, obtidas a 300 K, s?o caracter?sticas de amostras que possuemmais de uma fase. Em 77 K, o comportamento da curva de histerese ? influenciado pelapresen?a da hematita que ? antiferromagn?tica. J? em T = 4,2K, ? observado umcomportamento ferromagn?tico fraco. Al?m disso, verifica-se o efeito de ?exchange bias?.Os resultados obtidos das medidas de temperatura em fun??o do campo alternado s?opromissores para aplica??es em hipertermia magn?tica e outras aplica??es biom?dicas. / In this work, composites were prepared using high energy mechanical milling from the precursors hydroxyapatite - HAp (Ca10(PO4)6(OH)2) and metallic iron ( -Fe ). The main goal here is to study composites in order to employ them in magnetic hyperthermia for cancer therapy. The produced samples were characterized by X-ray di raction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), magnetization curves as a function of applied eld (MxH), and nally measurements of magnetic hyperthermia. The XRD patterns of the milled samples HAp/Fe revealed only the presence of precursor materials. The SEM showed clusters with irregular shapes. The magnetization curves indicated typical cases of weak ferromagnetic behavior. For samples submitted to grinding and annealing, the identi ed phases were: HAp (Ca10(PO4)6(OH)2), hematite (Fe2O3) and Calcium Iron Phosphate (Ca9Fe(PO4)7). Analyzing the results of MxH, there was a reduction of the saturation magnetization, given that the Fe was incorporated into HAp. Hysteresis curves obtained at 300 K are characteristics of samples possessing over a phase. At 77 K, the behavior of the hysteresis curve is in uenced by the presence of hematite, which is antiferromagnetic. Already at T = 4.2 K, it is observed a weak ferromagnetic behavior. Furthermore, there is the e ect of exchange bias. Regarding the magnetic hyperthermia, the results of temperature measurements as a function of the alternating eld are promising for applications in magnetic hyperthermia and other biomedical applications.

Made available in DSpace on 2014-12-17T14:58:23Z (GMT). No. of bitstreams: 1 MarinalvaFT_DISSERT.pdf: 2645446 bytes, checksum: d4a95fdf4bdc8c40f2876e653a2bb39f (MD5) Previous issue date: 2013-08-02 / Currently, vegetable oils have been studied for bio-lubricants base that fits the new environmental standards. Since, in a world full of finite natural resources, mineral oils bring consequences to the environment due to its low biodegradability and toxicity, also it is important to consider that synthetic oils have a high cost The aim of this work is to obtain a biolubricant additived with oxide nanoparticles (ZnO and CuO) for better resistance to friction and wear, which is not toxic to the environment and have better adherence under boundary lubrication. The methodology consisted in the synthesis of bio-lubricants (soybean and sunflower base) by epoxidation reaction. Then, some physical-chemical analysis in bio-lubricants are made to characterize theses lubricants, such as, density, acidity, iodine value, viscosity, viscosity index. Later, the lubricants were additive with nanoparticles. The tribological performance was evaluated by the equipment HFRR (High Frequency Reciprocating Rig) consisting of a wear test ball-plan type. The characterization of wear analysis was performed by SEM / EDS. The results show that bio-lubricants may be synthesized by reaction of epoxidation with good conversion. Tribological point of view, the epoxidized oils are more effective than lubricant additived with the oxide nanoparticles, they had lower coefficients of friction and better rate of film formation in the study. However, because they are environmentally friendly, bio-lubricants gain the relevant importance in tribological field / Atualmente, os ?leos vegetais tem sido base de estudo para biolubrificantes que se adequem ?s novas normas ambientais. Em um mundo cheio de recursos naturais finitos, os ?leos minerais, provenientes do petr?leo, trazem consequ?ncias ao meio ambiente devido sua baixa biodegradabilidade e toxicidade. Tamb?m deve-se considerar, os ?leos sint?ticos possuem um alto custo. O objetivo deste trabalho ? obter um biolubrificante aditivado com nanopart?culas de ?xido (ZnO e CuO) para uma melhor resist?ncia ao atrito e desgaste, que seja n?o t?xico ao meio ambiente e possua melhor ader?ncia em regime de lubrifica??o limite. Efetuou-se a s?ntese de biolubrificantes (soja e girassol) por rea??o de epoxida??o. Em seguida fizeram-se an?lises f?sico-qu?micas no biolubrificante para caracterizar os ?leos sintetizados, tais como; densidade, acidez, ?ndice de iodo, viscosidade, ?ndice de viscosidade. Posteriormente os mesmos foram aditivados com nanopart?culas. O desempenho tribol?gico foi avaliado pelo equipamento HFRR (High Frequency Reciprocating Rig), que consiste num ensaio de desgaste do tipo esfera-plano. A caracteriza??o do desgaste foi realizada atrav?s de an?lises de MEV/EDS. Os resultados demostraram que os biolubrificantes podem ser sintetizados por rea??o de epoxida??o, com boa convers?o. Do ponto de vista tribol?gico, os ?leos epoxidados puros s?o mais eficazes que os aditivados com nanopart?culas de ?xido, apresentaram menores coeficientes de atritos e melhor percentual de forma??o de filme neste estudo. Por?m, por serem ambientalmente corretos, os biolubrificantes ganham import?ncia relevante no meio tribol?gico

Made available in DSpace on 2014-12-17T15:14:43Z (GMT). No. of bitstreams: 1 AndreSWTS_capa_ate_secao2.pdf: 3305591 bytes, checksum: 5f27842b5915ba4ade82c5d3c89c759b (MD5) Previous issue date: 2007-12-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The e?ect of ?nite size on the magnetic properties of ferromagnetic particles systems is a recurrent subject. One of the aspects wide investigated is the superparamagnetic limit where the temperature destroys the magnetic order of ferromagnetic small particles. Above the block temperature the thermal value of the magnetic moment of the particle vanishes, due to thermal ?uctuations. The value of the blocking temperature diminishes when the size of the particle is reduced, re?ecting the reduction of the anisotropy energy barrier between the uniform states along the uniaxial axis. The increasing demand for high density magnetic media has recently attracted great research interest in periodic arrangements of nanometric ferromagnetics particles, approach in the superparamagnetic limit. An interesting conjecture is the possibility of stabilization of the magnetic order of small ferromagnetic particles (F) by interface coupling with antiferromagnetic (AF) substrate. These F/AF systems may also help to elucidate some details of the e?ect of exchange bias, because the e?ect of interface roughness and the paper of domain walls, either in the substrate or the particle, are signi?cantly reduced. We investigate the magnetic phases of small ferromagnetic particles on a antiferromagnetic substrate. We use a self-consistent local ?eld method, incorporating the interface ?eld and the dipole interaction between the spins of the ferromagnetic particle. Our results indicate that increasing the area of the interface favors the formation of the uniform state. Howere above a critical height value appears a state non-uniform is formed where the spins of in the particle s free surface are rotated with respect to the interface spins direction. We discuss the impact of the competition between the dipolar and interface ?eld on the magnetic charge, that controls the ?eld of ?ux leakage of the particle, and on the format of the hysteresis curves. Our results indicate that the liquid magnetic charge is not a monotonically increasing function of the height of the particle. The exchange bias may display anomalous features, induced for the dipolar ?eld of the spins near the F/AF interface / O efeito de tamanho ?nito nas propriedades magn?ticas de sistemas de part?culas ferromagn?ticos ? um tema recorrente. Um dos aspectos largamente investigados ? o limite superparamagn?tico em que a temperatura desestabiliza a ordem magn?tica de part?culas ferromagn?ticas pequenas. Acima da temperatura de bloqueio o valor m?dio t?rmico do momento magn?tico da part?cula se torna nulo, devido a ?utua??es t?rmicas. A temperatura de bloqueio diminui quando o tamanho da part?cula ? reduzido, re?etindo a queda na barreira de energia de anisotropia entre os estados de magnetiza??o uniforme ao longo do eixo uniaxial. A demanda crescente por meios de grava??o magn?tica de alta densidade tem atualmente despertado grande interesse de pesquisa em arranjos peri?dicos de part?culas ferromagn?ticas de dimens?es nanom?tricas, beirando o limite superparamagn?tico. Uma conjectura interessante, levantada experimentalmente, se refere ? possibilidade de estabiliza??o da ordem magn?tica de part?culas ferromagn?ticos (F) via o acoplamento de interface com substratos antiferromagn?ticos (AF) com temperatura de N?el acima da temperatura ambiente. Esses sistemas se prestam igualmente para elucidar alguns detalhes do efeito de Exchange bias , dado que, o efeito de rugosidade de interface e o papel de paredes de dom?nio, seja no substrato ou na part?cula, s?o reduzidos. Investigamos as fases magn?ticas de uma pequena part?cula ferromagn?tica, com diversas geometrias e disposi??es de deposi??o sobre um substrato antiferromagn?tico. Usamos um m?todo de campo local auto-consistente, incorporando o campo de interface e a intera??o dipolar entre os spins da part?cula ferromagn?tica. Nossos resultados indicam que aumentando a ?rea da interface favorece a forma??o do estado uniforme. Por?m se a altura da part?cula ? superior a um valor cr?tico surge um estado n?o-uniforme em que os spins se orientam de modo a minimizar a carga magn?tica super?cial. Discutimos o impacto que a competi??o entre esses efeitos tem na carga magn?tica l?quida, que controla o campo de fuga da part?cula e no formato das curvas de histerese. Nossos resultados indicam que a carga l?quida n?o ? uma fun??o monot?nicamente crescente da altura da part?cula e que o deslocamento da histerese pode sofrer altera??es relevantes, induzidas pelo campo dipolar, fugindo do padr?o esperado normalmente em sistemas F/AF extensos

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-03-20T17:21:12Z No. of bitstreams: 1 MarinalvaFerreiraTrajano_TESE.pdf: 6319363 bytes, checksum: 1a264d4d3fb0025a7862072124e8405a (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-03-22T12:58:55Z (GMT) No. of bitstreams: 1 MarinalvaFerreiraTrajano_TESE.pdf: 6319363 bytes, checksum: 1a264d4d3fb0025a7862072124e8405a (MD5) / Made available in DSpace on 2018-03-22T12:58:55Z (GMT). No. of bitstreams: 1 MarinalvaFerreiraTrajano_TESE.pdf: 6319363 bytes, checksum: 1a264d4d3fb0025a7862072124e8405a (MD5) Previous issue date: 2017-09-29 / O Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Engrenagens e outros conjuntos mec?nicos s?o muito importantes para a convers?o da energia e?lica em energia el?trica em turbinas e?licas, mas a sua durabilidade e efici?ncia s?o severamente prejudicadas por algumas quest?es tribol?gicas como corros?o, desgaste, deforma??o e fragmenta??o. Os lubrificantes utilizados para reduzir esse desgaste e deforma??o s?o de fontes n?o renov?veis podendo n?o ser vi?veis ambientalmente. Assim, surgem novas tecnologias que visam o desenvolvimento de produtos de fontes renov?veis substituindo o ?leo mineral e aditivo de extrema press?o. A este respeito, ?leos vegetais e novos aditivos inorg?nicos est?o sendo pesquisados como uma alternativa adequada para substituir os lubrificantes utilizados atualmente em engrenagens de turbinas e?licas. O objetivo desse trabalho foi sintetizar nanopart?culas est?veis inorg?nicas em ?leos vegetais por sputtering, desenvolvendo lubrificantes mais adaptados ao meio ambiente com aditivos mais eficientes. A metodologia aplicada est? divida em 5 etapas: 1- prepara??o do biolubrificante (?leo de girassol epoxidado); 2- caracteriza??o f?sico-quimica dos lubrificantes; 3- deposi??o das nanopart?culas por sputtering; 4- caracteriza??o da dispers?o e 5 avalia??o tribol?gica. Nas deposi??es foram utilizados tr?s n?veis de corrente de descarga e taxa de deposi??o (30 mA- 0,8 ?/s, 40 mA- 1,3 ?/s e 50 mA- 1,51 ?/s), tr?s diferentes concentra??es, em peso, de nanopart?culas (0,05%, 0,1% e 0,3%) e com alvo Cu para se obter nanopart?culas de cobre. As nanopart?culas formadas foram caracterizadas em fun??o do tamanho de part?cula pela t?cnica de SAXS e por MEV. A dispers?o das nanopart?culas foi analisada por Uv-Vis?vel, Polidispersividade, Potencial Zeta e SAXS. Para avaliar o desempenho tribol?gico foi utilizado o trib?metro HFRR. Os resultados mostraram que os biolubrificantes com melhoram o desempenho tribol?gico melhorando o desgaste e reduzindo atrito em superf?cies met?licas. Al?m disso, este m?todo de preparo do nanobiolubrificante eliminou o problema de dispers?o verificado por outras t?cnicas de dispers?o. / Gears and other mechanical assemblies are very important for the conversion of wind energy into electrical energy in wind turbines, but their durability and efficiency are severely hampered by some tribological issues such as corrosion, wear, deformation and fragmentation. The lubricants used to reduce this wear and deformation is from non-renewable sources and may not be environmentally viable. Thus, new technologies appear that aim at the development of renewable products replacing mineral oil and extreme pressure additive. In this regard, vegetable oils and new inorganic additives are being researched as a suitable alternative to replace the lubricants currently used in wind turbine gears. The objective of this work is to synthesize inorganic nanoparticles in vegetable oils by sputtering to obtain stable colloidal nanoparticles (NPs), developing lubricants more adapted to the environment with more efficient additives, with a better level of tribological performance. The applied methodology is divided in 5 steps: 1- preparation of the biolubrificante (epoxidized sunflower oil); 2- physico-chemical characterization of the lubricants; 3- deposition of the nanoparticles by sputtering; 4 - characterization of the dispersion and 5 tribological evaluations. In the depositions three discharge current levels (30 mA- 0.8 ? / s, 40 mA- 1.3 ? / s and 50 mA- 1.51 ? / s) and three deposition rates were used to obtain three different concentrations by weight of nanoparticles (0,05%, 0,1 % and 0,3%) and with Cu target to obtain copper nanoparticles. The nanoparticle formed was characterized as a function of the particle size by the SAXS technique and a sample by SEM. The dispersion of the nanoparticles was analyzed by Uv-Visible, Polydispersivity, Zeta Potential and SAXS. To evaluate the tribological performance was used the HFRR trbometer. The results showed that the biolubrificants with additives had good performace, improved wear and reduced friction on metal surfaces. In addition, this method of preparing the nanobiolubrifier eliminated the dispersion problem ascertained by other dispersion techniques.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-03-20T19:31:22Z No. of bitstreams: 1 JanineDeAraujoSilva_DISSERT.pdf: 3090092 bytes, checksum: b11ae8004e5eb556878f21976b10b352 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-21T22:51:22Z (GMT) No. of bitstreams: 1 JanineDeAraujoSilva_DISSERT.pdf: 3090092 bytes, checksum: b11ae8004e5eb556878f21976b10b352 (MD5) / Made available in DSpace on 2017-03-21T22:51:22Z (GMT). No. of bitstreams: 1 JanineDeAraujoSilva_DISSERT.pdf: 3090092 bytes, checksum: b11ae8004e5eb556878f21976b10b352 (MD5) Previous issue date: 2016-10-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O estudo para a obten??o de nanopart?culas de ouro (AuNPs) funcionalizadas por mol?culas bioativas tem se mostrado relevante no desenvolvimento de novas alternativas para tratamento do c?ncer. O presente trabalho descreve a s?ntese de AuNPs estabilizadas por dois derivados quinoxal?nicos, 2,3-dietanolaminaquinoxalina (DEQX) e 2-(2,3-di-idro-[1,4]oxazino[2,3-b]quinoxalin-4-il)etanol (OAQX), sintetizados por nosso grupo de pesquisa, verificados por possu?rem atividade antic?ncer em estudos envolvendo c?lulas. Para obten??o das AuNPs funcionalizadas com DEQX e OAQX, o glicerol foi utilizado como principal agente redutor. As AuNPs foram caracterizadas por espectroscopia ultravioleta-vis?vel (UV-Vis), infravermelho (FTIR-ATR) e microscopia eletr?nica de transmiss?o (TEM). Os resultados de UV-Vis indicaram que a melhor condi??o de s?ntese das AuNPs foi quando as propor??es de Au3+ em rela??o aos ligantes org?nicos foi de 1:0,2 e 1:1 para DEQX e OAQX, respectivamente. Nestas condi??es, foram obtidas AuNPs esf?ricas e monodispersas, com dimens?es m?dias de 9,7 e 11,5 nm quando nas estabiliza??es por DEQX e OAQX, respectivamente. O mecanismo de forma??o das part?culas foi proposto com base nos resultados experimentais, e parece envolver uma complexa??o entre Au3+ e os ligantes previamente ? forma??o das AuNPs. O fato das bandas em torno de 525 nm do espectro de UV-Vis, caracter?sticas das AuNPs, tornarem-se mais intensas e com melhor defini??o com o passar do tempo corroboram para essa hip?tese. Foi realizado um estudo relacionado ? estabilidade das AuNPs em fun??o do pH, onde foi verificado que as mesmas se mostraram relativamente est?veis em pH pr?ximo a 7,4. O ligante DEQX foi mais eficiente na estabiliza??o das AuNPs quando comparado ao OAQX. Os resultados obtidos no presente trabalho indicaram que foram obtidas AuNPs esf?ricas monodispersas funcionalizadas com duas esp?cies org?nicas bioativas, abrindo a possibilidade de explora??o destes sistemas para fins medicinais, em especial para o tratamento do c?ncer. / The study on obtainment of gold nanoparticles (AuNPs) functionalized with bioactive molecules have been shown to be relevant in the development of new alternatives for cancer treatment. This study describes the synthesis of AuNPs stabilized by two quinoxaline derivatives, 2,3- diethanolaminequinoxaline (DEQX) and 2-(2,3-di-hydro-[1,4]oxazine[2,3-b]quinoxaline-4-yl) ethanol (OAQX), synthetized by our research group, verified as possessing anticancer activity in studies involving cells. For the obtainment of AuNPs functionalized with DEQX and OAQX, glycerol was used as main reducing agent. The AuNPs were characterized by ultraviolet-visible spectroscopy (UV-Vis), by infrared (FTIR-ATR), and by transmission electronic microscopy (TEM). The results from the UV-Vis showed that the best synthesis condition of AuNPs happened when the proportions of Au3+ in relation to organic ligands were 1:0,2 and 1:1 for DEQX and OAQX, respectively. In those given conditions, monodispersed spherical AuNPs were obtained, with average size of 9.7 and 11.5 nm when stabilized by DEQX and OAQX, respectively. The particles formation mechanism proposed was based on the experimental results, and it appears to involve a complexation between Au3+ and the referred ligands previously to the formation of the AuNPs. The fact that the bands at around 525 nm from the UV-Vis spectrum - characteristics of AuNPs - have become more intense and with better definition over time corroborate to this assumption. A study related to the stability of AuNPs according to the pH was carried out, being thus possible to verify that they showed to be relatively stable at pH near 7,4. The DEQX ligand was more efficient on the stabilization of AuNPs when compared to the OAQX ligand. The results obtained in this work indicated the formation of spherical monodisperse AuNPs functionalized with two bioactive organic species. This leads to the possibility of exploitation of these systems for medical purposes, especially for cancer treatment.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-11-01T22:37:28Z No. of bitstreams: 1 RaimundoNazarenoDaSilvaConceicaoFilho_DISSERT.pdf: 12242083 bytes, checksum: 01e4da6c38f0cf877f871a80f9e59811 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-11-14T00:09:04Z (GMT) No. of bitstreams: 1 RaimundoNazarenoDaSilvaConceicaoFilho_DISSERT.pdf: 12242083 bytes, checksum: 01e4da6c38f0cf877f871a80f9e59811 (MD5) / Made available in DSpace on 2017-11-14T00:09:04Z (GMT). No. of bitstreams: 1 RaimundoNazarenoDaSilvaConceicaoFilho_DISSERT.pdf: 12242083 bytes, checksum: 01e4da6c38f0cf877f871a80f9e59811 (MD5) Previous issue date: 2017-09-01 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Neste trabalho utilizamos o m?todo qu?mico poliol para a prepara??o de nanopart?culas de Sm-Co. As amostras sintetizadas foram nomeadas das seguintes formas: ARS-0%; ARS-5%;ARS-7% e ARS-9%, sendo as porcentagens referente a varia??o do ?cido Ac?tico utilizado na s?ntese. A caracteriza??o estrutural foi realizada via difra??o de raio-X e microscopia eletr?nica de transmiss?o (MET). Os par?metros estruturais foram determinados pelo m?todo de Rietvelt utilizando o software Maud. As seguintes fases foram identificadas: Sm2Co7; Sm2Co17 e Sm5Co19. Para o estudo das propriedades magn?ticas, medidas com o magnet?metro de amostra vibrante foram utilizadas para obten??o de curvas de magnetiza??es em fun??o do campo magn?tico aplicado ? temperatura ambiente. O PPMS foi utilizado para medir curvas de magnetiza??o em fun??o da temperatura. As temperaturas de Curie obtidas est?o de acordo com as fases obtidas pelos m?todos de caracteriza??o estrutural. Foram obtidas imagens das amostras atrav?s do MEV e MET para estudo morfol?gico e determina??o do tamanho das nanopart?culas das amostras. Nossos resultados mostram a viabilidade do m?todo poliol para obten??o de nanopart?culas de Sm-Co e a influencia do ?cido Ac?tico no processo de s?ntese. / In this work we used the chemical polyol method for the preparation of Sm-Co nanoparticles. The synthesized samples were named in the following forms: ARS-0%; ARS-5%, ARS-7% and ARS-9%, being the percentages referring to the variation of Acetic Acid used in the synthesis. The structural characterization was performed by X-ray diffraction and transmission electron microscopy (TEM). The structural parameters were determined by the Rietvelt method using the Maud software. The following phases were identified: Sm2CO7; Sm2Co17 and Sm5Co19. For the study of magnetic properties, measurements with the vibrating sample magnetometer were used to obtain magnetization curves as a function of the magnetic field applied at room temperature. The PPMS was used to measure magnetization curves as a function of temperature. The Curie temperatures obtained are in accordance with the phases obtained by the structural characterization methods. Images of the samples were obtained through the SEM and MET for morphological study and determination of the size of the nanoparticles of the samples. Our results show the feasibility of the polyol method to obtain Sm-Co nanoparticles and the influence of Acetic Acid in the synthesis process.

Made available in DSpace on 2015-04-14T13:59:06Z (GMT). No. of bitstreams: 1 457483.pdf: 5023547 bytes, checksum: e9f63d304ec1410bd1e9d8f328ceaa18 (MD5) Previous issue date: 2014-02-28 / In this work we investigated the synthesis, characterization and contrast properties of core-shell nanoparticles of iron oxide coated with dextran and functionalized with amine groups. Fluorophores groups were incorporated on the nanoparticles surface, allowing their use as contrast agents for magnetic resonance imaging and optical microscopy. The nanoparticles synthesis was performed by the coprecipitation method of iron salts in basic medium, along with the polymer coating. The synthesis parameters were modified to investigate their influence on the size distribution of nanoparticles. Transmission electron microscopy observations and dynamic light scattering showed a magnetic iron oxide core with an average diameter around 10-15 nm and the total average hydrodynamic diameters between 16-50 nm, depending on the synthesis conditions. The FTIR spectra showed characteristics absorption bands pure dextran in the synthesized core-shell nanoparticles. The zeta potential analysis showed positive values close to zero and stability at neutral pH. The magnetization curves of the nanoparticles revealed superparamagnetic behavior, with the characteristic absence of hysteresis and no magnetization at zero field. The UV-vis and flow cytometry analysis revealed the presence of fluorescent groups in the nanoparticles and the feasibility of their use in optical imaging. Studies of relaxation times of the nuclear magnetization have shown the decrease of the magnetic resonance signal with increasing nanoparticles concentration, reducing the relaxation times T1 and T2 in the nanoparticle aqueous solutions. The relaxivities ratios (r2/r1) ranged between 5.06 and 51.0 and were within the value of iron oxide contrast agents commercially available. / Neste trabalho, pesquisou-se a s?ntese, a caracteriza??o e as propriedades de contraste por imagem de nanopart?culas core-shell de ?xido de ferro, revestidas com dextran e funcionalizadas com grupos amina. Grupos fluor?foros foram incorporados na superf?cie das nanopart?culas, possibilitando seu uso como agente de contraste para imageamento por resson?ncia magn?tica e por microscopia ?ptica. As s?nteses das nanopart?culas foram realizadas pelo m?todo de coprecipita??o de sais de ferro, com o pol?mero de revestimento. Par?metros da s?ntese foram modificados para averiguar sua influ?ncia na distribui??o de tamanho das nanopart?culas. Os resultados da morfologia e da distribui??o de tamanhos por TEM e DLS mostraram um n?cleo com di?metros m?dios entre 10-15 nm e di?metros hidrodin?micos m?dios entre 16-50 nm, dependendo do procedimento de s?ntese. Os espectros de FTIR apresentaram bandas de absor??o caracter?sticas das liga??es presentes no dextran puro e nas nanopart?culas sintetizadas. A an?lise do potencial zeta revelou valores positivos pr?ximos de zero e estabilidade em pH neutro As medidas de magnetiza??o revelaram comportamento superparamagn?tico pela aus?ncia de histerese na curva de magnetiza??o. As an?lises por UV-vis e por citometria de fluxo revelaram a presen?a dos grupos fluorescentes nas nanopart?culas e a viabilidade de seu uso em imagens ?pticas. Os estudos nos tempos de relaxa??o magn?tica nuclear mostraram efeitos de contraste, perturbando a intensidade de sinal com o aumento da concentra??o, diminuindo os tempos de relaxa??o T1 e T2 das solu??es aquosas de nanopart?culas. A rela??o entre as relaxividades (r2/r1) foi entre 5.06 e 51.0, dentro dos valores dos agentes de contrastes de ?xido de ferro comercialmente dispon?veis.

Made available in DSpace on 2014-12-17T15:41:47Z (GMT). No. of bitstreams: 1 WashingtonCMGpdf.pdf: 1072479 bytes, checksum: d37434aed1d2ae898ee7a9fd3701e0d7 (MD5) Previous issue date: 2009-04-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This work deals with the application of X-Ray Absorption Spectroscopy on the study of the behavior of Cu2+ ions in inverse micelles. The formation of copper nanoparticles in water-in-oil microemulsions in pseudo-ternary systems of cetyl trimethylammonium Bromide (CTAB) surfactant, butanol co-surfactant, heptane as oil phase and aqueous solutions of CuSO4.5H2O, and NaBH4. The microemulsions were prepared with a fixed percentage (60 %) of oil phase and a variable water to tensoative proportion. It was observed an increase on Cu2+ reduction by the sodium borohydride in microemulsions with 13 % of aqueous phase, independent of the reaction time. For the microemulsions in which the aqueous phase is composed only by the CuSO4 solution, it was observed that the color of the solution depends on the water to surfactant ratio. These changes in color were attributed to a competition for the hidratation water between the polar head of the tensoative and Cu2+ ions with the eventual substitution of oxygen by bromine atoms in the first coordination shell of Cu2+ ions / Neste trabalho estudou-se aplica??o da espectroscopia de absor??o de raios x no estudo do comportamento dos ?ons Cu2+ em micelas inversas. Estudou-se a forma??o de nanopart?culas de cobre em microemuls?es ?gua-em-?leo de sistemas pseudo-tern?rios tensoativo (brometo de hexadeciltrimetilam?nio, CTAB)-cotensoativo (butanol) / fase oleosa (heptano) / fase aquosa (solu??es de CuSO4.5H2O, e NaBH4). As microemuls?es foram preparadas fixando em 60% a fase ?leo (Heptano) e variando 40% de fase aquosa com tensoativo/cotensoativo na mesma propor??o, sendo que a fase aquosa do agente redutor NaBH4 foi usada em excesso de 0,4 mol.L-1 e 0,8 mol.L-1 em rela??o 0,2 mol.L-1 de fase aquosa de CuSO4.5H2O. Observou-se uma maior redu??o dos ?ons Cu2+ pelo boridreto de s?dio em microemuls?es com 13% de ?gua, independente do tempo de rea??o. Para as microemuls?es em que a fase aquosa corresponde a solu??o de CuSO4, observou-se uma depend?ncia na colora??o em fun??o da rela??o entre as concentra??es de ?gua/tensoativo. Essa mudan?a de colora??o foi atribu?da a uma competi??o pelas mol?culas de ?guas entre a cabe?a polar do tensoativo e os ?ons Cu2+ com uma eventual substitui??o do oxig?nio da primeira esfera de coordena??o por bromo

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-12-12T18:21:03Z No. of bitstreams: 1 RubensCapistranoDeAraujo_TESE.pdf: 5113380 bytes, checksum: 6c5c79e9dca9bf8ff407a71a0e02013e (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-12-13T19:53:41Z (GMT) No. of bitstreams: 1 RubensCapistranoDeAraujo_TESE.pdf: 5113380 bytes, checksum: 6c5c79e9dca9bf8ff407a71a0e02013e (MD5) / Made available in DSpace on 2017-12-13T19:53:41Z (GMT). No. of bitstreams: 1 RubensCapistranoDeAraujo_TESE.pdf: 5113380 bytes, checksum: 6c5c79e9dca9bf8ff407a71a0e02013e (MD5) Previous issue date: 2017-08-21 / Superf?cies superhidrof?bicas t?m sido objeto de muitos estudos devido ao grande interesse cient?fico e tecnol?gico para aplica??es como autolimpeza, anticorros?o, separa??o ?gua/?leo, microflu?dica, dentre outras. A superhidrofobicidade depende das caracter?sticas qu?micas e topologia das superf?cies. Neste trabalho, foi desenvolvido um novo m?todo de produ??o de revestimento superhidrof?bico nanoestruturado em materiais fibrosos, utilizando o processo de deposi??o de espuma. Com base no m?todo desenvolvido, revestimentos nanocomp?sitos de politetrafluoretileno e nanopart?culas de ?xido de c?lcio foram depositados sobre fibras de Poli?cido l?ctico para avalia??o de superhidrofobicidade. A influ?ncia de par?metros de processo como, concentra??o de nanopart?culas de ?xido de c?lcio, concentra??o de politetrafluoretileno, temperatura de polimeriza??o e tempo de polimeriza??o, foi avaliada. O revestimento foi caracterizado por ?ngulo de contato, difra??o de raios-x, espectroscopia no infravermelho com transformada de Fourier e reflect?ncia total atenuada, microscopia eletr?nica de varredura, microscopia de for?a at?mica, microscopia eletr?nica de transmiss?o e espectroscopia de raios-x de dispers?o de el?trons, espectroscopia fotoeletr?nica por raios-x, ensaio de repel?ncia a l?quidos com v?rios valores de tens?o superficial, ensaio de verifica??o da autolimpeza e ensaio de resist?ncia a lavagem e abras?o. Os resultados de difra??o de raios-x e espectroscopia no infravermelho com transformada de Fourier indicaram a presen?a de politetrafluoretileno e nanopart?culas de ?xido de c?lcio sobre a superf?cie das fibras de Poli?cido l?ctico, confirmando a deposi??o do revestimento pelo processo desenvolvido. Dentre os par?metros de processo estudados, a condi??o de 0,6% sobre o peso do material (spm) de nanopart?culas de ?xido de c?lcio, 80 g/l de politetrafluoretileno, 140?C e 90 segundos de polimeriza??o resultou no maior valor de ?ngulo de contato para o revestimento de politetrafluoretileno/nanopart?culas de ?xido de c?lcio (159,67? ? 1,05?). As imagens de microscopia eletr?nica de varrimento, microscopia eletr?nica de transmiss?o e espectroscopia de raios-x de dispers?o de el?trons e microscopia de for?a at?mica mostraram nanopart?culas de ?xido de c?lcio com formas esf?rica e retangular e altera??es morfol?gicas e topogr?ficas na superf?cie das fibras de Poli?cido l?ctico com a deposi??o do recobrimento. A espectroscopia fotoeletr?nica por raios-x confirmou a exist?ncia da presen?a de elemento qu?mico fl?or na superf?cie do revestimento. Os resultados dos testes de repel?ncia aquosa realizados utilizando uma s?rie de solu??es de ?gua/?lcool isoprop?lico com diferentes tens?es superficiais indicaram repel?ncia da superf?cie revestida a todas as solu??es testadas. As fibras com o revestimento de politetrafluoretileno/ nanopart?culas de ?xido de c?lcio tamb?m apresentaram propriedade de autolimpeza fazendo com que uma gota de ?gua removesse a sujeira da superf?cie. O revestimento manteve a superhidrofobicidade mesmo ap?s 25 ciclos de lavagem e 100 ciclos de abras?o. Em resumo, o processo de fabrica??o apresentado nesta pesquisa utilizando a deposi??o de espuma mostrou-se simples e pr?tico para deposi??o de revestimentos superhidrof?bicos em fibras e tecidos. O revestimento de politetrafluoretileno/nanopart?culas de ?xido de c?lcio depositado em fibras de Poli?cido l?ctico via deposi??o de espuma apresentou propriedades superhidrof?bicas. / Superhydrophobic surfaces are of great scientific and technological interest for applications such as self-cleaning, anticorrosion, oil/water separation, microfluidics, among others. The superhydrophobicity depends on surface chemistry and topology. In this work, a new method for producing nanostructured superhydrophobic coatings on fibrous materials using foam deposition was developed. Based on the developed method, polytetrafluoroethylene/calcium oxide nanocomposite coating was deposited on polylactic acid fibers and the superhyphobicity was evaluated. The influence of processing parameters such as nanoparticle concentration, polytetrafluoroethylene concentration, polymerization temperature and polymerization time was evaluated. The nanocoating was analyzed by contact angle, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, transmission electron microscopy and electron-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, liquid repellency test with various surface tension values, self-cleaning check test and wash and abrasion resistance test. The results of X-ray diffraction and Fourier transform infrared spectroscopy indicated a presence of polytetrafluoroethylene and calcium oxide nanoparticles on the surface of the polylactic acid fibers, confirming the deposition of the coating by the process developed. Among the processing parameters studied, the condition of 0.6 wt.% of calcium oxide nanoparticles, 80 g/l polytetrafluoroethylene, 140 ?C and 90 seconds of polymerization resulted in the highest contact angle value for the nanocomposite coatings (159.67? ? 1.05?). Scanning electron microscopy images, transmission electron microscopy and electron-dispersive X-ray spectroscopy and atomic force microscopy showed calcium oxide nanoparticles with spherical and rectangular shapes and morphological and topographic changes on the surface of polylactic acid fibers with the deposition of the coating. X-ray photoelectron spectroscopy confirmed the presence of the chemical element fluorine on the surface of the coating. The results of the aqueous liquid repellency tests performed on the coated surface using a series of isopropyl alcohol/water solutions of different surface tensions indicated repellency to all tested solutions. The self-cleaning properties of the coated fibers were determined by the removal of dirt by water droplet flow. The nanocomposite coating maintained the superhydrophobicity even after 25 wash cycles and 100 abrasion cycles. In summary, the manufacturing process presented in this research using foam deposition, proved to be simple and practical for the deposition of superhydrophobic coatings in fibers and fabrics. The polytetrafluoroethylene/calcium oxide coating deposited on polylactic acid fibers by foam deposition showed superhydrophobic properties.