Made available in DSpace on 2018-08-01T21:58:49Z (GMT). No. of bitstreams: 1 tese_11824_Natã Carlos Lira Madeira.pdf: 3934576 bytes, checksum: 3446460b8bf031109c1ca2a28cc2e544 (MD5) Previous issue date: 2018-02-19 / Um dos maiores problemas encontrados durante o processamento e extração de petróleo é a deposição de asfaltenos, fenômeno que causa diversos prejuízos como o entupimento de poços e formação de danos na rocha reservatório. A literatura encontra-se dividida sobre a afirmação de que as resinas são capazes de diminuir a formação de agregados, devido a sua similaridade na estrutura química com os asfaltenos. Contudo, existem estudos que afirmam que as resinas não são capazes de atuarem como surfactantes e o fator que limita o tamanho do agregado seriam as interações de repulsão existentes entre os próprios asfaltenos. Em virtude dessa problemática, esse trabalho foi realizado para verificar a influência das resinas no tamanho dos agregados asfaltênicos formados. Para esse estudo, foram utilizadas 3 amostras de petróleo de diferentes origens e ºAPI, obtidas em território nacional e realizada a extração dos asfaltenos a partir da norma ASTM D6560-00. A extração de resinas ocorreu por cromatografia a partir da adaptação da norma ASTM D2549. Em seguida, foi realizado a caracterização das amostras por RMN de ¹H e ¹³C, ao qual permitiu verificar a arquitetura dos asfaltenos em questão e o teor de carbonos aromáticos, resultado que deduz a quantidade de anéis fundidos na amostra que é um fator relacionado com a estabilidade dos asfaltenos, devido a possibilidade de interações do tipo π-π stacking. Também, peor RMN de ¹H e ¹³C foi possível ter uma ideia da estrutura dos óleos e resinas. A verificação da influência das resinas no tamanho dos agregados ocorreu por meio da técnica DOSY, com experimentos realizados em tolueno deuterado em uma concentração de 5 % (m/m) de asfaltenos, adicionando 5 mg de resinas por três vezes, obtendo as massas de 5, 10 e 15 mg de resinas na solução contendo asfaltenos. Com os valores de difusão relativa medidos no experimento foi possível verificar que a amostra de menor ºAPI possuia um maior caráter aromático nos asfaltenos, mostrando agregados de maior tamanho e mais estáveis, tendo pouquíssima influência das resinas no tamanho dos agregados.Contudo as amostras de maior ºAPI apresentaram uma influência significativa no tamanho dos agregados a partir da adição de 10 mg de resinas, indicando a existência dessa influência no tamanho dos agregados, mas observando que para ocorrer tal influência, são necessárias as condições estruturais necessárias e compatíveis das resinas com seus respectivos asfaltenos.

Yes / The plasma protein binding (PPB) of a drug plays a key role in both its pharmacokinetic and pharmacodynamic properties. During lead optimisation, medium and high throughput methods for the early determination of PPB can provide important information about potential PKPD profile within a chemotype or between different chemotype series. Diffusion ordered spectroscopy (DOSY) is an NMR spectroscopic technique that measures the diffusion of a molecule via applying varying magnetic field gradients, where the diffusion is primarily affected by its molecular size/weight and solution viscosity. Here, we describe the use of DOSY for a rapid and straight forward method to evaluate the PPB of drug molecules, using their binding to bovine serum albumin (BSA) as a model. / The full-text of this article will be released for public view at the end of the publisher embargo on 11 Jun 2025.

This thesis concentrates on diffusion-ordered spectroscopy (DOSY): a technique in liquid state nuclear magnetic resonance (NMR) spectroscopy that is able to distinguish different chemical species by their size in solution, and measure species’ diffusion coefficients. DOSY is an invaluable tool to analyse and resolve the signals of mixtures of chemicals in solution. DOSY measures an ensemble of nuclei in a mixture, using pulsed field gradients (PFGs) to encode, and later decode, the positions of spins. This provides information on the root mean square distance that spins diffuse during a delay between a pair of PFGs, which allows the determination of diffusion coefficients. However, DOSY is susceptible to a number of complications. Where a sample convects, the distance molecules move during the delay is greater than for simple diffusion, and the estimate of the diffusion coefficient becomes greater than the true value. Rayleigh-Bénard convection has been known in NMR for a long time, and is known to result from heating the base of an NMR sample, giving rise to negative vertical temperature gradients. Here, cooling the base (and inadvertently the sides) of the sample is also shown to cause convection from transverse temperature gradients, known as Hadley convection and commonly observed in atmospheric circulation. The theory for convection from transverse temperature gradients is given and recommendations to reduce convection in NMR are made. DOSY analysis can also be challenging where signals from different species overlap. In such instances, it can help to reduce the overlap, which can be achieved by collapsing multiplets into singlet signals: pure shift NMR is a technique that uses band-selection in order to refocus scalar coupling during the free induction decay, leaving pure chemical shift information. However, PFGs can vary in strength across the sample, which can have an effect on band selective experiments, such as Zangger-Sterk pure shift experiments, in the measured peak amplitudes, and where DOSY is combined with the Zangger-Sterk pure shift sequence, the apparent diffusion coefficients are also altered, seemingly as a function of chemical shift. A correction for this is given, simply using a DOSY and a DOSY pure shift experiment, as an alternative to the current literature method (gradient mapping).An investigation into an emulsion, agrochemically important for the delivery of active ingredients (fertiliser,pesticides, etc.) to plants, was then undertaken, in the hopes of finding restricted diffusion, but instead discovering substantial chemical exchange on the diffusional timescale. Finally a program was written for the automated acquisition of DOSY data, without the need for a human controller to calibrate DOSY parameters for the optimum acquisition.

CEZAR, Henrique Machado. Estudo fitoquímico dos talos de Croton velutinus baill e análise dos componentes do óleo essencial de Ocimum basilicum var. purpurascens BENTH e de seus derivados por espectroscopia ordenada por difusão (DOSY). 2016. 160 f. Dissertação (Mestrado em Química)-Universidade Federal do Ceará, Fortaleza, 2016. / Submitted by Aline Mendes (alinemendes.ufc@gmail.com) on 2017-01-20T20:53:42Z No. of bitstreams: 1 2016_dis_hmcezar.pdf: 13002046 bytes, checksum: e5aaa91c1849e9c1fdc95a126cb6a497 (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2017-01-23T20:29:39Z (GMT) No. of bitstreams: 1 2016_dis_hmcezar.pdf: 13002046 bytes, checksum: e5aaa91c1849e9c1fdc95a126cb6a497 (MD5) / Made available in DSpace on 2017-01-23T20:29:39Z (GMT). No. of bitstreams: 1 2016_dis_hmcezar.pdf: 13002046 bytes, checksum: e5aaa91c1849e9c1fdc95a126cb6a497 (MD5) Previous issue date: 2016 / Croton velutinus Baill is a plant belonging to the family Euphorbiaceae found in the “cadeia do espinhaço”, that comprises the States of Minas Gerais and Bahia, occurring in rocky fields and sandy soils. Several species of Croton have been studied due to different therapeutics applications. There is no report about the phytochemical study of C. velutinus found in the literature. The hexane and ethanolic extracts of stalks of C. velutinus were subjected to chromatographic procedures, resulting in isolation of two flavonoids, Casticin and 5-hydroxi-3,6,7,4’-tetrametoxyflavone, two sesquiterpenes (6S,7S) 7,11-dihydroxi-bisabol-2-en-4-one and Delobanone and a inedited diterpene clerodane, velutinoic acid. The extracts of Croton velutinus were subjected to assays of larvicidal, antioxidant activities, acetylcholinesterase enzyme inhibition and angiotensin I converting enzyme inhibitors. The second part of this work, consisted in essential oil analysis of Ocimum basilicum var. purpurascens BENTH, plant known like alfavaca roxa by GC-MS and DOSY. The major components in the essential oil were identified as eugenol (65,2%) and β-caryophyllene (23,4%). The resolution of eugenol and β-caryophyllene was performed by Matriz-assisted DOSY (MAD) using the non-ionic surfactant Brij 78 as matrix. Were prepared eugenol derivatives: eugenyl acetate, cis and trans-isoeugenol, for to be analyzed by MAD in binary and ternary mixtures containing vanillin like one of components. The diffusion coeficients of eugenol and β-caryophyllene in the essential oil vary considerably with the change of solvent of CDCl3 to the mixture DMSO-d6:D2O (1:1) with ∆EC 7,27% to ∆EC 89,12% separation, respectively, whereas the binary mixture of this compounds vary of ∆EC 9,39% to 98,33%. The eugenol and vanillin 10 mM mixture showed the variation of ∆EC 35,5% in presence of Brij 78. The larvicidal activity of essential oil, eugenol and their derivatives were obtained from 3rd stage larvae of mosquito Aedes aegypti, and the essential oil showed the most efficient. The structural characterization of the isolated compounds was achieved by spectroscopy methods (MS, IR and NMR 1H e 13C, including one and two dimensional techniques) and by comparison with literature dates. / Croton velutinus Baill é uma planta pertencente à família Euphorbiaceae encontrada na cadeia do espinhaço, região que compreende os estados de Minas Gerais e Bahia, ocorrendo em campos rupestres e solo arenoso. Várias espécies de Croton têm sido estudadas devido às suas diferentes aplicações terapêuticas. A espécie C. velutinus ainda não apresenta estudos fitoquímicos descritos na literatura, o que motivou a investigação química e farmacológica desta planta. Os extratos hexânico e etanólico dos talos de C. velutinus foram submetidos a procedimentos cromatográficos resultando no isolamento de dois flavonoides Casticina e 5-hidroxi-3,6,7,4’-tetrametoxiflavona, dois sesquiterpenos, (6S,7S) 7,11-diidroxi-bisabol-2-en-4-ona e delobanona, e um diterpeno clerodano inédito na literatura, o ácido velutinóico. Os extratos de Croton velutinus foram submetidos a ensaios de atividades larvicida, antioxidante, inibição da enzima acetilcolinesterase e da enzima conversora da angiotensina I. A segunda parte deste trabalho consistiu na análise do óleo essencial de Ocimum basilicum var. purpurascens BENTH, planta conhecida como alfavaca roxa, por CG-EM e DOSY. Os componentes majoritários identificados no óleo essencial foram eugenol (65,2%) e β-cariofileno (23,4%), os quais foram isolados e analisados por DOSY assistida por matriz (MAD) utilizando o surfactante não iônico Brij 78 como matriz. Foram preparados os derivados do eugenol: acetato de eugenila, cis e trans-isoeugenol, para serem analisados por MAD em misturas binárias e ternárias contendo vanilina como um dos componentes. Os coeficientes de difusão do eugenol e β-cariofileno no óleo essencial variaram consideravelmente com a mudança do solvente de CDCl3 para a mistura DMSO-d6:D2O (1:1) com separação de ∆EC de 7,27% para ∆EC 89,12%, respectivamente, enquanto a mistura binária destes compostos variou de ∆EC 9,39% para 98,33%. A mistura de eugenol e vanilina a 10 mM mostrou separação de ∆EC de 35,5% na presença de 40 mM de Brij 78. As atividades larvicidas do óleo essencial, eugenol e dos derivados foram obtidas frente às larvas no 3º estágio do mosquito Aedes aegypti, sendo o óleo essencial o mais eficiente. As substâncias químicas isoladas tiveram suas estruturas elucidadas por métodos espectroscópicos (EM, IV e RMN 1H e 13C, incluindo técnicas uni e bidimensionais) além de comparação com dados da literatura.

No description available.

Treatment of vision impairing diseases involves drug transport through the vitreous humor. Diffusion cells were used to measure macro-scale (mutual) diffusivity (Dm) to understand how solute size affects diffusion through the vitreous humor of rabbit and porcine eyes. Solutes examined included timolol maleate, dexamethasone sodium phosphate (DMSP), sodium fluorescein, and FITC-dextrans (4, 40, and 150kDa). Diffusivity was inversely dependent on solute size. The Dm's of small solutes in the vitreous were 30 – 65% of that in PBS, while the Dm's of large solutes were 40 – 60% of that in PBS. Extrapolations to the human eye produced similar results using diffusivities based on either species. We used Diffusion Ordered NMR Spectroscopy to measure micro-scale (self) diffusivity (Ds) of DMSP through vitreous humor. The Ds and Dm were significantly different in PBS, but similar in vitreous. A method for obtaining in vivo imagery and data of vitreous fluorophore distribution is also presented.

Treatment of vision impairing diseases involves drug transport through the vitreous humor. Diffusion cells were used to measure macro-scale (mutual) diffusivity (Dm) to understand how solute size affects diffusion through the vitreous humor of rabbit and porcine eyes. Solutes examined included timolol maleate, dexamethasone sodium phosphate (DMSP), sodium fluorescein, and FITC-dextrans (4, 40, and 150kDa). Diffusivity was inversely dependent on solute size. The Dm's of small solutes in the vitreous were 30 – 65% of that in PBS, while the Dm's of large solutes were 40 – 60% of that in PBS. Extrapolations to the human eye produced similar results using diffusivities based on either species. We used Diffusion Ordered NMR Spectroscopy to measure micro-scale (self) diffusivity (Ds) of DMSP through vitreous humor. The Ds and Dm were significantly different in PBS, but similar in vitreous. A method for obtaining in vivo imagery and data of vitreous fluorophore distribution is also presented.

Made available in DSpace on 2016-12-23T14:41:50Z (GMT). No. of bitstreams: 1 Emanuele Catarina da Silva Oliveira.pdf: 3488830 bytes, checksum: fc0d45235f94ffa597f9bb41f45af330 (MD5) Previous issue date: 2013-03-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Heavy crude oils have attracted a growing interest from oil industries around the world. In this scenario, asphaltenes, which are molecules known for their low reactivity and high molecular weight, have received special attention in recent decades, due to the problems they cause during oil processing. In an effort to minimize these problems, researchers have increasingly looked for a better understanding of aspects such as molecular structure, stability and physicochemical properties of asphaltenes, as well as for the development of methods to prevent their unwanted precipitation. In recent decades, nuclear magnetic resonance (NMR) has been widely used as a tool for the study of petroleum and its derivatives. The analysis of 1H and 13C NMR spectra allows the direct determination of a series of structural parameters such as the fractions of aromatic carbons and of carbon atoms in alkyl chains. Diffusion-ordered NMR spectroscopy (DOSY), which is based on the results of pulsed-field gradient (PFG) experiments, is a new developed NMR technique highly useful for the elucidation of complex mixtures. This work sought to identify the differences in average molecular parameters of asphaltenes from national crudes and to correlate them with the physicochemical properties of the asphaltene and of the original crude. The aim was also to investigate and to compare the asphaltenes among themselves, using data such as diffusion coefficient, concentration of these compounds in the oil and state of aggregation. Extraction and quantification of the amount of asphaltenes were performed using ASTM D6560-00 standard and the characterization of the asphaltenes was performed using the following analytical techniques: elemental analysis, atomic absorption spectrometry, mass spectrometry, high-resolution 1H and 13C NMR and DOSY. Significant changes were observed in almost all studied parameters. To study the asphaltene aggregation behavior using DOSY, the asphaltenes were diluted in various concentrations of deuterated toluene and the DOSY spectra were correlated with their respective states of aggregation. The diffusion properties were highly dependent on the concentration and type of oil from which the asphaltene was extracted / Os petróleos pesados são de grande interesse das indústrias petroleiras ao redor do mundo. Com isso, os asfaltenos, moléculas conhecidas por sua baixa reatividade e alto peso molecular, têm recebido uma atenção especial nas ultimas décadas, devido aos problemas que causam durante o processamento do óleo. Buscando minimizar estes problemas, pesquisadores têm investido cada vez mais no conhecimento da estrutura molecular e estabilidade dos asfaltenos, no entendimento de suas propriedades físico-químicas e no desenvolvimento de metodologias que impeçam sua precipitação indesejada. Nas últimas décadas, a ressonância magnética nuclear (RMN) tem sido amplamente utilizada como ferramenta no estudo de petróleos e seus derivados. A obtenção de espectros de RMN de 1H e 13C permite a determinação direta de uma série de parâmetros estruturais, tais como a fração de carbonos aromáticos e de carbonos ligados em uma cadeia alquílica. O desenvolvimento de novas técnicas de RMN, como a espectroscopia de RMN ordenada pela difusão (DOSY), baseada na sequência de gradiente de campo pulsado (PFG), têm se mostrado excelentes ferramentas na elucidação de misturas complexas. Neste trabalho, procurou-se identificar as diferenças observadas nos parâmetros moleculares médios dos asfaltenos provenientes de petróleos nacionais, bem como correlacioná-las com as propriedades físico-químicas do próprio asfalteno e do óleo de origem. Pretende-se, ainda, investigar e comparar os asfaltenos, a partir de dados de coeficiente de difusão, concentração desses compostos no óleo e forma de agregação. A extração e quantificação do teor de asfaltenos foram realizadas utilizando-se a norma ASTM D6560-00 e a caracterização dos asfaltenos foi realizada através das técnicas analíticas de: análise elementar, espectrometria de absorção atômica, espectrometria de massas de alta resolução, RMN de 1H e 13C e, RMN DOSY. Foram observadas modificações significativas em praticamente todos os parâmetros estudados. No estudo do comportamento de agregação com a técnica RMN DOSY os asfaltenos foram diluídos em concentrações diferentes de tolueno deuterado e os espectros correlacionados com os seus respectivos estados de agregação. As propriedades de difusão se mostraram altamente dependentes da concentração e do tipo de óleo utilizado para a obtenção dos asfaltenos

La RMN est un outil analytique extrêmement puissant pour l’analyse quantitative et structurale, et est très utilisée en biologie structurale. C’est dans ce contexte que nous avons choisi d’étudier les interactions par RMN. Le premier système choisi est un système de polymères, les PEO. Ils sont caractérisés par plusieurs grandeurs physiques dont l’indice de polydispersité. Cet indice représente la distribution de taille d’une population de polymères. Nous avons développé une nouvelle méthode de diffusion par RMN, la DOSY afin d’accéder à cet indice : J. Viéville et al. / Journal of Magnetic Resonance 212 (2011)169–173 Le deuxième système complexe étudié est un type de molécules chimiques mimétiques de l’ADN, les PNA, acides nucléiques peptidiques. Les PNA possèdent des bases nucléiques leur permettant de former des liaisons avec l’ADN ou l’ARN. Nous avons montré par des analyses de RMN que les PNA en solution peuvent former des complexes très stables avec des températures de fusion élevées. Ces analyses RMN sont complétées par des analyses de dichroïsme circulaire.Afin de compléter notre panel d’études sur les interactions moléculaires par RMN, nous avons étudié les interactions protéine-ligand avec greffage de la protéine sur phase solide : J.M.P. Viéville et al. / Journal of Pharmaceutical and Biomedical Analysis 89 (2014) 18–23 / NMR is a powerfull technique we decided to extend to follow interactions in complex mixtures. First part is about polydispersity index of polymer which is an important physical parameter when working with polymers. We developed here a new method, based on PEO analysis, using diffusion experiments (DOSY) by NMR to assess the polydispersity index: J. Viéville et al. / Journal of Magnetic Resonance 212 (2011) 169–173. In a second time, we worked on peptidic nucleic acids, PNA. These chemicals molecules are designed to bind DNA or RNA for clinical studies. We studied PNA in solution, by NMR to showwhich kind of interactions they form on themselves. We found very stable complexes with high fusion temperatures. Circular dichroism measurements were helpful for fusion temperature determination and structural studies. To complete this panel, we were interested in the study of protein-ligand interaction. We developed a new way to follow them, using a grafted protein on a solid phase based on HR-MAS NMR technology: J.M.P. Viéville et al. / Journal of Pharmaceutical and Biomedical Analysis 89 (2014) 18–23

La première partie de ce mémoire concerne l’étude en solution de systèmes à base de POMset de cations organiques de polarité/taille variables. Ainsi, l’étude des interactions entre unanion Keplerate noté {Mo132} et une large série de cations organiques (composée d’ions alkylammonium AA) a nécessité la mise en place d’une méthodologie spécifique utilisant la RMNDOSY de 1H. La méthode s’est révélée particulièrement efficace et a permis non seulement demettre clairement en évidence l’existence d’interactions anion-cation fortes mais aussil’extraction des constantes d’association à partir d’un traitement quantitatif des données. Cetteétude révèle que le facteur qui domine le processus d’association anion-cation résulte d’un« effet hydrophobe » directement lié au caractère apolaire du cation organique et polaire dusolvant. Les constantes de stabilité sont en accord avec des interactions plutôt fortes. ParParailleurs, une expérience spécifique a permis de titrer les 20 pores présents à la surface de l’ionKeplérate, montrant ainsi la spécificité du processus d’association.La seconde partie de ce mémoire concerne la conception de matériaux à base de Képlerate enjouant sur la nature des cations imidazolium qui lui sont associés. Les phases solides ont étécaractérisées par spectrométrie infrarouge, analyse élémentaire, EDX et analysethermogravimétrique. Ces études montrent que dans certaines conditions, ces systèmes seaffichent un comportement type cristal liquide.La troisième partie s’intéresse spécifiquement aux interactions ionique et/ou van der Waals àl’origine de phénomènes de structuration. L’anion cyclique[Na2K2{Mo4O4S4(H2O)3(OH)2}2(P8W48O184)]32- ( noted 1) a été isolé à l’état solide sous laforme de sels de DODA (dioctadécyl-diméthyl-ammonium) ou d’imidazolium. L’analysestructurale de ces phases par RMN MAS de 1H, 13C et 31P montre sans ambigüitél’organisation des chaines alkyles. Ces résultats croisés avec la microscopie optique polarisée,l’analyse thermique différentielle et la diffraction des rayons X aux petits angles montrentclairement la formation de phases mésomorphes lamellaires dont l’espacement estdirectement lié à la longueur des chaines alkyles. / Herein, we report the use of 1H DOSY NMR methodology to track the interaction between aninorganic multireceptor capsule, referring to the well-defined spherical Keplerate-type{Mo132} ion and a series of organic cation (including tetraalklylammonium). The obtainedresults reveal a strong dependence of the self-diffusion coefficient of the cationic guestsbalancing from the solvated to the plugging situations. Quantitative analysis of the data basedon two-site exchange regime, involving the 20 independent {Mo9O9} receptors of the capsule,allowed determining the stability constants associated to the plugging process of the pores.Surprisingly, the affinity of the capsule for a series of cationic guests increases continuouslywith its apolar character. Such observations evidence that the major factor dictating selectivityin the trapping process is mainly the so-called “hydrophobic effect”.Further investigation focused on the design of Keplerate-based materials where theammonium cations was replaced by imidazolium cations. The obtained materials werecharacterized in the solid state by FT-IR, TGA and elemental analysis. These materials exhibitliquid crystalline phase as evidenced by polarized optical microscopy and DSC, however,folding of the alkyl chain prohibit the formation of well organized mesophase. Finally, thisstrategy was extended to cyclic [Na2K2{Mo4O4S4(H2O)3(OH)2}2(P8W48O184)]32- which wasisolated as DODA or imidazolium salt. Solid state NMR evidence the well organization of thesolid. The obtained materials exhibit smectic A liquid crystalline phase and packed ashexagonal lamellar arrangement in the solid state.