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is is a study of the relationship between structure, mechanical properties and relaxing behavior of the polypropylene. The structure was evaluated by the quantity the solid phase content (SPC). This was defined as mathematical result of free induction decay (FID) signal from pulsed 1H-NMR. The solid phase content is a quite new structural parameter representing the quantity for description of semi-crystalline polymers. Whereas pulsed 1H-NMR is non-destructive, accurate and repeatable, it becomes a unique tool for a description of mechanical, structural, physical-mechanical changes of polypropylene within the time and temperature. Particularly, this method registers the small changes in the time-dependant shipments during secondary crystallization with small structure changes.

Parmi les nombreux pathogènes fongiques susceptibles d’infecter les épis de maïs, les espèces appartenant au genre Fusarium sont particulièrement préoccupantes pour la filière maïsicole. La fusariose est susceptible d’induire des pertes de rendement considérables et est fréquemment associée à une contamination des épis par des mycotoxines. Un des leviers prometteur repose sur la sélection génétique de plantes résistantes à Fusarium et à l’accumulation de mycotoxines. Plusieurs Quantitative Trait Loci (QTL) ont été identifiés d’après la caractérisation moléculaire de la résistance à la fusariose chez le maïs. Cependant malgré les progrès des approches génétiques, les mécanismes moléculaires impliqués restent en grande partie inconnus. L’identification de métabolites majeurs associés à la résistance reste donc indispensable pour la création d’un outil d’aide à la sélection variétale. Une approche métabolomique combinant de la spectrométrie de masse et de la 1H-RMN a été mise au point pour identifier un ensemble de métabolites de défense, constitutifs ou induits par l’infection, susceptibles d’intervenir dans la résistance à Fusarium. Cette approche a été appliquée aux grains à deux stades de développement sur 20 variétés présentant des degrés de résistance contrastés inoculés ou non avec une souche de Fusarium graminearum toxinogène par le canal des soies. Les résultats obtenus mettent en évidence un panel de métabolites liés à la résistance ou la sensibilité des variétés de maïs. / Fusarium graminearum is the main causal agent of maize ear rot or Gibberella ear rot (GER), an important fungal disease affecting maize. GER leads to significant economic loss and serious health issues due to the ability of F. graminearum to produce mycotoxins such as type B trichothecenes. One promising approach to control Giberella Ear Rot and reduce mycotoxins contamination is to promote host-genetic resistance. Several Quantitative Trait Loci (QTLs) have been identified in maize. However molecular basis to resistance to Fusarium infection remains largely unknown and the success of selection for GER resistance is still challenging. Biochemical approaches can provide valuable insights in the mechanisms crops employ against F. graminearum and its production of mycotoxins. A biochemical profiling could actually be an efficient way to decipher plant-pathogen interactions and progress in screening resistant maize lines. This study aims to elucidate the metabolic profiling of F. graminearum resistance and toxin accumulation in kernels toward the combination of high resolution mass spectrometry and 1H NMR to identify a large set of metabolites, preformed, constitutive as well as inducible defense metabolites that could play a key role in GER resistance. This approach was applied to kernels harvested at two developmental stages. Twenty genotypes with contrasting levels of resistance were inoculated, or not, with a toxigenic Fusarium graminearum strain through the silk channel. The obtained data allowed highlighting a set of biochemical compounds linked to the resistance or susceptibility of maize genotypes

Master of Science / Department of Grain Science and Industry / Yong Cheng Shi / Waxy wheat starch (WWS) containing little or no amylose has unique properties for food and industrial uses. Hydroxypropylation, a widely used means for modifying starches, could enhance functionalities of starch by substituting hydroxyl groups in starch. There are limited numbers of literatures regarding hydroxypropylation of WWS. WWS hydroxypropylated with 3.0-9.0% propylene oxide (PO) were prepared and compared to hydroxypropylated normal wheat starch (NWS) and hydroxypropylated waxy maize starch (WMS). The molar substitution (MS) of the resulting hydroxypropylated NWS, WWS and WMS was 0.055-0.151, 0.048-0.133, and 0.049-0.139, respectively. Gelatinization temperatures and enthalpy of hydroxypropylated starches were significantly lower than those of their unmodified counterparts and the extent of decrease was positively correlated to the MS. Differential scanning colorimetry (DSC) results showed that hydroxypropylation reduced the retrogradation of the starches during the storage after gelatinization but there were differences between the starches. For the same level of PO reaction (3 and 5% PO), hydroxypropylated WWS retrogradated less than hydroxypropylated WMS, suggesting that for the same level of cold storage stability, less PO is needed for WWS. After reacted with 6% PO, MS was 0.092 and 0.094, respectively, for WWS and WMS, and no retrogradation was observed for those hydroxypropylated starches, indicating that at MS ~0.094, hydroxypropyl groups prevents amylopectin chains from re-associating and forming crystalline structures. In contrast, a higher level of PO (9%) was needed to react with NWS to achieve the hydroxypropylated starch with an MS of 0.151 that gave no retrogradation. Consistent with microscopic observation results, Micro-Visco-Amylograph (MVA) analysis showed hydroxypropylated starches developed viscosity at lower temperatures and had improved hot and cold viscosities. The specific characteristics of hydroxypropylated starches are related to the degree of hydroxypropylation. Therefore, it is critical to determine the level of hydroxypropylation in modified starches. 1H NMR is a simple and rapid means of determining hydroxypropyl (HP) group in modified starches. In this study, a method to prepare a HP starch for NMR analysis was improved. The optimum parameters proposed to hydrolyze HP starches were 10% starch solid content, 3.5% (wt.%) DCl in D2O as the solvent, sodium acetate as an internal standard, heating at 90oC for 1 h. Optionally, 6% (v/v) trifluoroacetic acid-d as the water-peak shifting reagent. Six hydroxypropylated starch samples and two commercial cross-linked and hydroxypropylated starch samples were hydrolyzed with this modified method before 1H NMR analysis, and the results of HP group content in the samples were in agreement with the results from an enzyme-catalyzed method, which indicate that the improved acid hydrolysis method is applicable for both hydroxypropylated starch and cross-linked and hydroxypropylated starch.

Orientador: Anita Jocelyne Marsaioli / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-25T07:45:46Z (GMT). No. of bitstreams: 1 Martins_LucasGelain_D.pdf: 5948717 bytes, checksum: d64f37183bfefec1cedc88b263d32340 (MD5) Previous issue date: 2014 / Resumo: Nesta tese consiste no estudo de interações supramoleculares utilizando diferentes metodologias de Ressonância Magnética Nuclear de hidrogênio (RMN de 1H), tais como ROESY 1D, RMN-DOSY e RMN-STD. Os sistemas supramoleculares foram abordados em dois casos de estudo diferentes. O Capítulo I tem como objeto de estudo interações do fármaco Dapsona com diferentes carreadores de fármacos (ß-CD, SBE-ß-CD e lipossoma de EPC), com a finalidade de encontrar formulações nas quais a Dapsona seja mais solúvel. Os complexos binários e ternário formados foram determinadas por medidas de difusão molecular. Foram observadas as formações dos complexos Dap/ß-CD, Da-/SBE-ß-CD, Dap/EPC e o ternário Dap/ß-CD/EPC, os quais contribuem para o aumento de solubilidade do fármaco. O objeto de estudo apresentado no Capítulo II é a inibição da enzima acetilcolinesterase por dois alcaloides, a Fisostigmina e a Crinina. Para determinação das constantes de dissociação aparentes foram utilizados os crescimentos iniciais das curvas de saturação obtids por RMN-STD para construção das Isotermas de Langmuir. De acordo com os valores de constantes obtidos foi possível concluir que a AchE tem mais afinidade com a Fisostigmina do que com a Crinina / Abstract: This thesis consists of the supramolecular interactions study applying different Nuclear Magnetic Resonance methodologies (1H NMR) such as 1D ROESY, DOSY-NMR and STD-NMR. The supramolecular systems were addressed in two different case studies. In chapter I Dapsone solubility was the case study. To solve the solubility problem the interactions between Dapsone and various drug carriers (ß-CD , SBE-ß-CD and EPC liposome) were characterized in terms of the binary and ternary complexes structure using NMR method, such as 1D ROESY and STD-NMR and apparent association constants were determined by measuring molecular diffusion using DOSY-NMR. Dap/ß-CD, Dap/SBE-ß-CD, Dap/EPC and Dap/ß-CD/EPC complexes were observed and Dapsone water solubility was increased. The case study in Chapter II is the inhibition of acetylcholinesterase by two alkaloids, Physostigmine and Crinina. The apparent dissociation constants were determined using the initial growth saturation curves obtained by STD-NMRto construct the Langmuir isotherms. The constants showed that the AChE has more affinity for the Physostigmine than Crinine / Doutorado / Quimica Organica / Doutor em Quimica

Orientador: Jarbas José Rodrigues Rohwedder / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-22T12:58:01Z (GMT). No. of bitstreams: 1 Killner_MarioHenriqueMontazzolli_D.pdf: 3491134 bytes, checksum: 684c66e65646bff8d702f6275096bfa6 (MD5) Previous issue date: 2013 / Resumo: No presente trabalho foram desenvolvidos novos métodos analíticos empregando espectroscopia NIR e de RMN H, visando o monitoramento on-line da reação de transesterificação de óleos vegetais para a produção de biodiesel e determinação de parâmetros de qualidade de diesel combustível através da espectroscopia de RMN H. Empregando a espectroscopia NIR foi utilizada pela primeira vez a região espectral compreendida entre 5928 e 5959 cm para a determinação on-line, por meio de um modelo de regressão multivariada, das taxas de conversão dos triglicerídeos provenientes de óleo de soja em ésteres de ácidos graxos (biodiesel). O modelo desenvolvido foi avaliado no monitoramento de duas reações de transesterificação conduzidas a 20 ± 0,2 °C e 55 ± 0,2 °C que apresentaram erros médios de previsão para um conjunto de validação de 0,6 e 1,0% de conversão, respectivamente. De maneira similar foram desenvolvidos outros 3 métodos analíticos empregando um espectrômetro de RMN H de bancada de baixo campo para a determinação das taxas de conversão dos triglicerídeos provenientes do óleo de semente colza em ésteres metílicos de ácidos graxos. O primeiro método utiliza as áreas dos picos dos prótons metoxílicos dos ésteres de ácidos graxos e dos prótons etilênicos da cadeia de ácidos graxos para a determinação direta das taxas de conversão dos triglicerídeos. Um segundo método utiliza um modelo de regressão PLS para a determinação das taxas de conversão. Finalmente, o terceiro método emprega os desvios químicos dos prótons hidroxílicos do metanol e glicerol presentes na fase oleica para determinar as taxas de conversão dos triglicerídeos em ésteres. Outro importante resultado alcançado durante o desenvolvimento do trabalho foi o entendimento da partição das moléculas dos alcoóis (metanol e glicerol) entre as duas fases que constituem o meio reacional durante o processo de transesterificação. Este fato é importante para compreender melhor o mecanismo de reação de produção de biodiesel, uma vez que a taxa de reação depende da quantidade de metanol e catalisador dissolvidos inicialmente na fase oleica. A possibilidade de identificar os valores da partição dos alcoóis ao final da reação possibilita também o desenvolvimento de técnicas de separação que permitam otimizar a recuperação de biodiesel e metanol em uma planta de produção de biodiesel, refletindo diretamente na redução dos custos. Modelos de calibração PLS empregando espectros de RNM H de baixo campo também foram desenvolvidos para a determinação de diversos parâmetros de qualidade de diesel combustível B5, como: Massa Específica, Curva de Destilação para 10%, 50%, 85% e 90% de recuperação, Número de Cetano e Ponto de Fulgor. Os espectros foram adquiridos sem qualquer tipo de preparo de amostra ou utilização de padrão interno. Todos os modelos desenvolvidos apresentaram valores de RMSEP inferiores às reprodutibilidades das técnicas analíticas empregadas atualmente como referência pelas normas ASTM e ABNT NBR. A técnica de RMN H de baixo campo foi empregada também para a determinação do Teor de Biodiesel nas amostras de diesel combustível, apresentando um erro relativo médio de 2,5% em relação a técnica analítica de referência / Abstract: The present work reports on the development of new analytical methods, based on NIR and H NMR spectroscopy, aiming at on-line monitoring of the transesterification reaction of vegetable oils to produce biodiesel, and the determination of quality parameters of diesel fuel applying H NMR spectroscopy. The NIR spectral region between 5928 and 5959 cm-1 was used for the first time for on-line determination, employing a multivariate model, of the conversion ratio of triglycerides from the soybean oil into fatty acid methyl esters (biodiesel). The developed model was evaluated on the transesterification reaction monitoring of two new reactions carried out at 20 ± 0.2 °C and 55 ± 0.2 °C which showed RMSEP of 0.6 and 1.0 %, respectively. In a similar way 3 analytical methods were developed using a bench-size low-field NMR H spectrometer to determine the triglycerides (rapeseed oil) conversion ratios into fatty acid methyl esters. The first method applies the area of the methoxylic protons peak of fatty acid methyl esters and the ethylenic protons peak of fatty acid chain for direct determination of the triglycerides conversion ratios. A second method applies a PLS regression model to determine the conversion ratio. finally, a third method applies the hydroxylic protons chemical shift of methanol and glycerol present in the oleic phase to correlate the conversion ratio of triglycerides into esters. Another important result obtained during the development of this work was the comprehension of partitioning of alcohol molecules (methanol and glycerol) between the two phases that constitute the reactional medium during biodiesel production process. This fact is relevant to understand the reaction mechanism of the biodiesel production, because the reaction rate strongly depends on the methanol and catalyst amount initially dissolved in the oleic phase. Also, the possibility of identification of the alcohols partitioning values at the end of the reaction process helps in the development of new separation techniques to optimize the biodiesel and methanol recovering in a biodiesel producing plant, directly influencing the process costs. PLS regression models applying the low-field H NMR spectra were also developed for the determination of different quality parameters of diesel fuel (B5), such as: Specific Gravity, Distillation Curve (10%, 50%, 85% e 90% of recovering), Cetane Number and Flash Point. The spectra were acquired without adding any reference compound or sample pre-treatment. All regression models developed showed RMSEP values lower than the reproducibility of the analytical techniques used as reference by ASTM and ABNT NBR. The low-field H NMR technique were also used to determine the biodiesel content in diesel fuel samples, showing a mean relative error of 2.5% in comparison to the standard analytical technique / Doutorado / Quimica Analitica / Doutor em Quimica

The expected outcome of this project is to develop a general strategy to functionalize dispersions, by noncovalent adsorption of HMW surfactants, ultimately for applications such as hydrophobic coatings with high hiding power and hardness, improved mechanical properties via pigment-latex interactions, improved substrate adhesion or improved freeze-thaw stability. So far, we have produced poly (methyl methacrylate-co-butyl acrylate) latexes in the presence of HMW surfactants via emulsion polymerization and demonstrated stronger adsorption of HMW surfactants on particle surface than sodium dodecyl sulfate (SDS). In addition, we have developed surfactant-free latexes, poly (methyl methacrylate-co-butyl acrylate-co-methacrylic acid), as models for post functionalization with high molecular weight surfactants. The successful transfer of surfactants onto particle surface from liquid crystals was indicated by the increase in zeta potential and confirmed via chemical shifts variation in 1H NMR spectra. Additionally, the HMW surfactants were used for dispersing hydrophobic inorganic particles, such as hydrophobic carbon black, in aqueous phase, providing an indication of the general applicability and versatility of our approach.

Dans un marché globalisé où 40% du vin consommé est importé, le contrôle de la traçabilité est un enjeu majeur de la filière viti-vinicole. L'authentification du vin est le processus pouvant faire appel à différentes méthodes analytiques devant pouvoir contrôler trois paramètres fondamentaux : l’origine géographique, le cépage et le millésime. La spectroscopie RMN 1H quantitative (RMNq) est aujourd'hui considérée comme un outil très prometteur pour l'étude de l'authenticité des vins. Lors de cette thèse, une technique de dosage de 40 composés majoritaires des vins par RMN 1H a été développée. Elle permet l’acquisition d’une information riche et complexe en une seule analyse non-spécifique. La capacité de cette technique à authentifier un vin a été démontrée suite à une collaboration avec le Château Mouton-Rothschild, par comparaisons avec des analyses officielles réalisées par la DGDDI et DGCCRF de Pessac (SCL). La détermination d’un seuil de conformité a été établie en prenant en compte l’évolution naturelle des vins en bouteille. Une étude de caractérisation des vins rouges de Bordeaux a été menée. La singularité de ces vins a été observée par comparaison avec d’autres vins français, mettant en évidence des métabolites caractéristiques des vins de Bordeaux. Les résultats fournissent une description globale du potentiel de la RMN 1H pour l’authentification des vins. / In a globalized market where 40% of the wine consumed is imported, traceability control is a major challenge for the wine industry. Wine authentication is the process that can use different analytical methods able to control three fundamental parameters: geographical origin, grape variety and vintage. Quantitative 1H NMR spectroscopy (qNMR) is now considered as a very promising tool for studying wine authenticity. During this thesis, a technique was developed for the determination of 40 major wine compounds by 1H NMR. It allows the acquisition of rich and complex information in a single non-specific analysis. The ability of this technique to authenticate a wine has been demonstrated following a collaboration with Château Mouton-Rothschild, by comparison with official analyses carried out by the DGDDI and DGCCRF of Pessac (SCL).The determination of a compliance threshold has been established by taking into account the natural evolution of bottled wines. A characterization study of Bordeaux red wines was carried out. The singularity of these wines was observed in comparison with other French wines, highlighting the characteristic metabolites of Bordeaux wines. The results provide a global description of the potential of 1H NMR for wine authentication.

Yes / Diffusion ordered 1H-NMR spectroscopy (DOSY) is a useful, non-destructive technique for analysing polymer hydrodynamic size and intrinsic/solution viscosity. However, to date there has been no investigation of DOSY under variable temperature conditions that allow trends in polymer conformation to be determined. Poly(2-ethyl-2-oxazoline) (P(EtOx)) is a hydrophilic polymer that has the potential to replace poly(ethylene glycol) (PEG) in biomedical applications. Applying DOSY to a series of narrow-distribution P(EtOx) revealed that the apparent hydrodynamic radii scaled with molecular weight as expected. By altering the temperature of the solution the trends in Flory-type exponents were determined, enabling the determination of the power laws related to the coil-globule conformation of linear polymers directly from NMR data. These measurements were complicated by the onset of convection currents at higher temperatures, which impose a limit to the effective measurement range of ca. 10–35 °C. It was revealed that P(EtOx) had a more expanded random coil conformation than PEG, and it trended towards θ conditions at the lower critical solution temperature. In comparison, PEG was approximately in θ-conditions at room-temperature. This shows the use, and limitations of DOSY in polymer conformation analysis, and applies it to P(EtOx), a polymer which has not been analysed in this manner before. / University of Ghent (Grant Number: RM1602-1695)

A series of Fe2+ spin crossover (SCO) complexes [Fe(5/6)]2+ employing hexadentate ligands (5/6) with cis/trans-1,2-diamino cyclohexanes (4) as central building blocks were synthesised. The ligands were obtained by reductive amination of 4 with 2,2′-bipyridyl-6-carbaldehyde or 1,10-phenanthroline-2-carbaldehyde 3. The chelating effect and the rigid structure of the ligands 5/6 lead to exceptionally robust Fe2+ and Zn2+ complexes conserving their structure even in coordinating solvents like dmso at high temperatures. Their solution behavior was investigated using variable temperature (VT) 1H NMR spectroscopy and VT Vis spectroscopy. SCO behavior was found for all Fe2+ complexes in this series centred around and far above room temperature. For the first time we have demonstrated that the thermodynamics as well as kinetics for SCO can be deduced by using VT 1H NMR spectroscopy. An alternative scheme using a linear correction term C1 to model chemical shifts for Fe2+ SCO complexes is presented. The rate constant for the SCO of [Fe(rac-trans-5)]2+ obtained by VT 1H NMR was validated by Laser Flash Photolysis (LFP), with excellent agreement (1/(kHL + kLH) = 33.7/35.8 ns for NMR/LFP). The solvent dependence of the transition temperature T1/2 and the solvatochromism of complex [Fe(rac-trans-5)]2+ were ascribed to hydrogen bond formation of the secondary amine to the solvent. Enantiomerically pure complexes can be prepared starting with R,R- or S,S-1,2-diaminocyclohexane (R,R-trans-4 or S,S-trans-4). The high robustness of the complexes reduces a possible ligand scrambling and allows preparation of quasiracemic crystals of [Zn(R,R-5)][Fe(S,S-5)](ClO4)4·(CH3CN) composed of a 1 : 1 mixture of the Zn and Fe complexes with inverse chirality. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.