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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Application of Xanthates to the Synthesis of Azaindanes and to the C-H Functionalization of Heteroaromatics / Application des Xanthates à la Synthèse des Azaindanes et à la Fonctionnalisation C-H des Hétéroaromatiques

Huang, Qi 19 December 2017 (has links)
Dans cette thèse, nous avons entrepris une aventure pour découvrir une application plus large de la chimie du xanthate dans la construction de cycles fusionnés et l'alkylation directe des hétéroarènes. Au chapitre II, nous avons abordé le problème de la préparation de l'azaindane en tirant parti de la capacité des xanthates à agir à la fois sur l'addition intermoléculaire et la cyclisation intramoléculaire. Au chapitre III, une étude sans précédent sur la fonctionnalisation directe des pyrazines a été décrite, conduisant à des pyrazines hautement fonctionnalisées avec de bons rendements et une bonne régiosélectivité. Enfin, au chapitre IV, nous avons développé une méthode de méthylation et de fluorométhylation des hétéroarènes. / In this thesis, we have undertaken an adventure to discover wider application of xanthate chemistry in the construction of fused cycles and direct alkylation of heteroarenes. In Chapter II, we have tackled the problem of preparation of azaindane by taking advantage of the ability of xanthates to mediate both intermolecular addition and intramolecular cyclisation. In Chapter III, an unprecedented investigation into the direct functionalization of pyrazines was described, leading to highly functionalized pyrazines in good yields and good regioselectivity. Finally, in Chapter IV, we have developed a method for the methylation and fluoromethylation of heteroarenes.
22

Supercritical carbon dioxide as a green media for simultaneous dyeing and functionalisation : A study on disperse dyeing and silicone functionalisation for water repellency of polyester fabric

Schulz, Anika January 2019 (has links)
Textile processing methods such as conventional exhaustion dyeing, pre-treatments and printing consume high amounts of water and use partly toxic and hazardous chemicals which are non-degradable. These chemicals (e.g. excess amount of dye, additives and catalysts) remain partially in the waste-water which is drained out and ends up polluting the environment. The supercritical carbon dioxide dyeing technology presents an eco-friendly and water-free method with reduced use of chemicals and energy. The benefits of such technology are currently not overcoming the relative high investment costs which impede its full implementation into the textile industry. This study presents an approach to extent the application of the eco-friendly supercritical carbon dioxide technology. It combines the well-studied supercritical carbon dioxide dyeing process for polyester with the functionalisation process to obtain water repellent surface properties. As water repellent (substance) environmentally benign silicones are used. Results showed that the simultaneous dyeing and functionalisation process was feasible assessed by the compatibility of the dye and silicone in the system. Silicone and dye did not interfere in each other’s functionality (colour strength and water contact angle). Further the process temperature and silicone molecular weight showed no influence on the colour strength of the fabric whereas the water contact angle (water repellence) increased with increasing temperature. The resulting polyester fabric showed acceptable colour strength yet did not obtain sufficient water repellent properties despite the increase in water contact angle of the treated samples to the untreated reference sample. The poor water repellence is suggested to be caused by the hydrophobic functional groups of the silicones oriented towards each other rather than toward the outer fabric surface. Overall the thesis is promoting research which combines eco-friendly technologies including environmental benign chemicals for the textile industry. Silicones are widely used in textile processing not only as water repellents, but also as anti-foaming agents, lubricants and softeners. Therefore a water-free and eco-friendly application method can benefit a wide range of finishing processes.
23

Designing functional magnetic nanoparticles with flame spray pyrolysis for bio-applications

Li, Dan, Chemical Sciences & Engineering, Faculty of Engineering, UNSW January 2009 (has links)
Magnetic nanoparticles (MNPs) hold great promise in the fields of biology and medicine. The synthesis of functional MNPs with precisely controlled crystallographic, physicochemical, and magnetic properties on a large scale still remains the challenge today. This thesis reports the exploration of liquid-fed flame spray pyrolysis (FSP) in the synthesis of functional MNPs, their surface modifications, and potential bio-applications. Superparamagnetic and ferromagnetic maghemite (γ-Fe2O3) nanoparticles, and silica-coated maghemite (SiO2/γ-Fe2O3) nanocomposites were synthesised using FSP. The size of γ-Fe2O3 was controllable from 6 to 53 nm, with morphology evolving from a disordered near-spherical shape to fully ordered 2-D hexagonal/octagonal platelet. The saturation magnetisation (Ms) increased from 21 to 74 emu/g with increasing particle size, up to 13 nm when Ms approached the bulk γ-Fe2O3 characteristics. In the case of SiO2/γ-Fe2O3, three distinct morphologies, namely the single segregated γ-Fe2O3 core- SiO2 shell, transitional mixed morphologies, and multi γ-Fe2O3 cores embedded in submicron SiO2 shell, were obtained. The core size, composite size, and morphology of γ- Fe2O3 were tunable by varying %SiO2 loading and the use of a quartz tube enclosure during flame synthesis. The magnetic behaviour correlated well with the crystal microstructure. Following the core particle design, protein adsorption-desorption behaviour on FSP-madeMNPs was studied. Bovine serum albumin (BSA) adsorption was found to follow the Langmuir isotherm, with high binding capacities (150−348 mg BSA/g particle) and fast association constants. Electrostatically governed BSA orientations were proposed for different particle-buffer systems. The adsorbed BSA was effectively recovered by pH-shift using K2HPO4. Subsequently, terminal amine, aldehyde, carboxylic, epoxy, mercapto and maleimide functionality were anchored onto the FSP-made γ-Fe2O3 particles. These versatile functional groups led to conjugation of active trypsin. The immobilised trypsin exhibited superior durability with >60% residual activity after one week, and excellent reusability for >5 cycles. The trypsin-conjugated MNPs are promising carriers in proteomics, demonstrating good substrate specificity with equivalent or better sequence coverage compared to free trypsin in insulin and BSA digestion. In another application, a refined silanisation procedure simultaneously reduced γ-Fe2O3 to Fe3O4, and generated thiol enriched surface for matrix metalloproteinase-2 (MMP-2) conjugation. The highly active MMP-2-conjugated MNPs could potentially enhance the interstitial transport of macromolecule/nanoparticles in drug delivery.
24

Designing functional magnetic nanoparticles with flame spray pyrolysis for bio-applications

Li, Dan, Chemical Sciences & Engineering, Faculty of Engineering, UNSW January 2009 (has links)
Magnetic nanoparticles (MNPs) hold great promise in the fields of biology and medicine. The synthesis of functional MNPs with precisely controlled crystallographic, physicochemical, and magnetic properties on a large scale still remains the challenge today. This thesis reports the exploration of liquid-fed flame spray pyrolysis (FSP) in the synthesis of functional MNPs, their surface modifications, and potential bio-applications. Superparamagnetic and ferromagnetic maghemite (γ-Fe2O3) nanoparticles, and silica-coated maghemite (SiO2/γ-Fe2O3) nanocomposites were synthesised using FSP. The size of γ-Fe2O3 was controllable from 6 to 53 nm, with morphology evolving from a disordered near-spherical shape to fully ordered 2-D hexagonal/octagonal platelet. The saturation magnetisation (Ms) increased from 21 to 74 emu/g with increasing particle size, up to 13 nm when Ms approached the bulk γ-Fe2O3 characteristics. In the case of SiO2/γ-Fe2O3, three distinct morphologies, namely the single segregated γ-Fe2O3 core- SiO2 shell, transitional mixed morphologies, and multi γ-Fe2O3 cores embedded in submicron SiO2 shell, were obtained. The core size, composite size, and morphology of γ- Fe2O3 were tunable by varying %SiO2 loading and the use of a quartz tube enclosure during flame synthesis. The magnetic behaviour correlated well with the crystal microstructure. Following the core particle design, protein adsorption-desorption behaviour on FSP-madeMNPs was studied. Bovine serum albumin (BSA) adsorption was found to follow the Langmuir isotherm, with high binding capacities (150−348 mg BSA/g particle) and fast association constants. Electrostatically governed BSA orientations were proposed for different particle-buffer systems. The adsorbed BSA was effectively recovered by pH-shift using K2HPO4. Subsequently, terminal amine, aldehyde, carboxylic, epoxy, mercapto and maleimide functionality were anchored onto the FSP-made γ-Fe2O3 particles. These versatile functional groups led to conjugation of active trypsin. The immobilised trypsin exhibited superior durability with >60% residual activity after one week, and excellent reusability for >5 cycles. The trypsin-conjugated MNPs are promising carriers in proteomics, demonstrating good substrate specificity with equivalent or better sequence coverage compared to free trypsin in insulin and BSA digestion. In another application, a refined silanisation procedure simultaneously reduced γ-Fe2O3 to Fe3O4, and generated thiol enriched surface for matrix metalloproteinase-2 (MMP-2) conjugation. The highly active MMP-2-conjugated MNPs could potentially enhance the interstitial transport of macromolecule/nanoparticles in drug delivery.
25

Graphène synthétisé par dépôt chimique en phase vapeur : du contrôle et de la compréhension des défauts à l'échelle atomique jusqu'à la production de dispositifs fonctionnels macroscopiques / Graphene produced by chemical vapor deposition : from control and understanding of atomic scale defects to production of macroscale functional devices

Kalita, Dipankar 25 June 2015 (has links)
Si le graphène est un candidat prometteur pour de nombreuses applications, il reste des questions fondamentales à résoudre. Les objectifs de cette thèse visent à obtenir une crois- sance de graphène de haute qualité, à développer de nouveaux concepts de transfert pour réaliser de nouveaux dispositifs tout en contrôlant la formation de défauts dans sa struc- ture. Nous avons été en mesure d'augmenter la surface d'une monocouche polycristalline de graphène d'une échelle de quelques centimètres à celle d'une plaquette de silicium sans changer de chambre CVD. D'autre part, nous avons démontré une méthode permettant de diminuer la densité de nucléation et ainsi d'obtenir du graphène monocristallin de quelques centaines de microns. Concernant la réalisation de nouveaux dispositifs, nous avons obtenu des circuits à base de graphène polycristallin empilés par transferts successifs où la région de bicouche artificielle se comporte comme un bicouche intrinsèque. Nous avons également développé une nouvelle méthode pour suspendre le graphène à l'échelle macroscopique sur des supports en piliers. Dans un tel système, les contraintes dans le graphène restent in- férieures à 0,2%. Par la suite une méthode de dépôt d'électrodes par voie sèche a été développée pour éviter toute dégradation du graphène. Ce processus de transfert a été amélioré pour atteindre des tailles de substrats allant jusqu'à 4 pouces pour le silicium et le saphir. Il a été enfin utilisé comme électrode transparente d'une LED à puits quantiques pour remplacer des électrodes Ni / Au . Nous avons mis au point des procédés de création sélective de défauts sur le graphène. Tout d'abord des défauts ont été induits chimiquement de façon contrôlable et ont été analysés par spectroscopie Raman et microscopie électronique en transmission qui ont révélé un mécanisme en deux étapes de formation de défauts dans la structure de graphène. Nous avons également étudié l'effet des défauts chargés adsorbés sur la surface du graphène sans former de liaisons avec lui. Contrairement à la littérature où les particules chargées sont déposées a posteriori, les nanoparticules chargées étaient présentes pendant la croissance sur cuivre. Nous interprétons l'existence d'une bande de phonons D' très intense devant celle de la D, et encore jamais signalée avec la présence de ces nanoparticules / Though graphene is strong candidate to make various applications, still there are issues that need to be resolved. The purpose of this thesis is to grow high quality graphene and transfer it to make new graphene based devices and to engineer defects into graphene structure. We have been able to increase the growth polycrystalline monolayer graphene from few centimeter scale to wafer scale without changing the CVD chamber. At the same time, we have demonstrated a method to decrease the nucleation density which allows us to grow large single crystal graphene from few to hundreds of micrometer. Concerning new design of graphene based devices, the polycrystalline graphene was trans- ferred to create artificial bilayer crossbars where the bilayer region behaved like naturally grown bilayer graphene. We have also developed a novel method of suspending graphene in macroscopic scale in pillared surface. In such a system, the strain in graphene is found to be less than 0.2%. Thereafter a completely dry method of depositing electrodes was developed which prevents damaging of graphene. The scale and process of transferring graphene was improved to different substrates such as 4 inch Si and sapphire substrates. It was used as transparent electrode to in a quantum well LED to replace the Ni/Au electrodes. We have been able to engineer defects into graphene. Firstly defects were induced in a controllable way using chemical method and were analyzed using Raman spectroscopy and Transmission Electron Microscopy which revealed a two step mechanism of defect formation in the graphene structure. We have also studied the effect of charged defects which adsorb onto the graphene surface without forming bonds with it. Unlike in literature where charged particles were deposited onto graphene, here the charged nano particles were present dur- ing the growth process in the copper foil. We believe that due to these nano particles, the intensity of D' phonon is greatly enhanced. Such anomalously higher intensity of D' band compared to D band has not been reported before
26

Streamlined synthesis of taxol analogues

Rodriguez, Patricia Fernandez January 2017 (has links)
This thesis centres on the synthesis of taxol analogues via late-stage hydroxylation with P450 enzymes. To accomplish this, the taxane core, specifically taxa-4(5),11(12)-dien-2-one, was synthesised by classical synthetic methods, and subsequently oxidised using P450<sub>BM3</sub> mutants. Chapter 1 introduces enzymatic catalysis, and the advantages and disadvantages of its application to organic synthesis. Additionally, an overview of taxol, including its discovery, mode of action, biosynthesis and large-scale production, and a summary of the previously reported approaches to the taxane core are described. Chapter 2 details the problems encountered and solutions implemented when reproducing Baran's route to taxa-4(5),11(12)-dien-2-one. Furthermore, approaches to some of its intermediates and an alternative route to taxa-4(5),11(12)-dien-2-one, which is based on Baran's, are discussed. Chapter 3 describes the development of a new, practical and short synthetic route to taxa-4(5),11(12)-dien-2-one which, ultimately, led to 1,3-di-epi-taxa-4(5),11(12)-dien-2-one. Additionally, the application of this route to the synthesis of a model compound and attempts to convert this racemic synthesis into an enantioselective route are reported. Finally, the enzymatic oxidation of taxa-4(5),11(12)-dien-2-one and related molecules using P450<sub>BM3</sub> mutants is explored in Chapter 4. A preliminary study to determine the substrate enantioselectivity of the mutants is also described, along with the biological assays of the oxidised compounds produced during the study.
27

Functionalisation of electrospun nanofibre for lanthanide ion adsorption from aqueous solution

Pereao, Omoniyi Kolawole January 2018 (has links)
Philosophiae Doctor - PhD (Chemistry) / Rare earth elements (REEs) have widespread use and importance for industrial applications due to their metallurgical, optical and electronic properties. Several typical hydrometallurgical techniques such as adsorption, chemical precipitation, filtration, ion exchange and solvent extraction techniques have been used for separation and recovery of the rare earth metals from aqueous solutions. Adsorption was recognised as one of the most promising methods due to its simplicity, high efficiency and availability. Many adsorbents are being investigated but there are few adsorbents containing specific functional groups in practical use for REEs recovery. This aim of this study was to develop a nanofibre based adsorbent containing glycolic acid functional groups for the recovery of rare earth metals. Polystyrene (PS) and polyethylene terephthalate (PET) nanofibres were prepared by the electrospinning technique, glycolic acid functional groups were grafted onto the PS or PET nanofibres and the potential of the two modified nanofibre adsorbents for adsorption of Ce3+ or Nd3+ from aqueous solution were investigated and compared. The adsorption experiments were carried out to investigate the effect of different adsorption parameters such as pH, contact time and initial concentration in a batch system in order to achieve the objectives of this research.
28

Antibody conjugates : integrated approach towards selective, stable and controllable bioconjugation / Conjugués d'anticorps : approche intégrative pour une bioconjugaison plus sélective, stable et contrôlable

Dovgan, Igor 21 September 2017 (has links)
Au cours de la dernière décennie, les anticorps conjugués à des médicaments cytotoxiques ou des oligonucléotides ont acquis une grande attention dans la communauté scientifique en raison des propriétés uniques des anticorps, tels que leur long temps de circulation dans le sérum et leur sélectivité élevée par rapport à leur cible. Par exemple, les conjugués d'anticorps (ACs) sont de plus en plus appliqués en thérapie ciblée contre le cancer ou en bioimagerie. Par conséquent, le développement de méthodologies fiables pour la préparation des AC est actuellement en pleine expansion. Cependant, la conjugaison et la préparation contrôlables des ACs avec une structure définie rencontrent encore de nombreux obstacles en raison de l'excès élevé et de la variété des groupes réactifs dans la structure des anticorps, qui sont accessibles pour la conjugaison. En outre, les technologies de liaison actuelles sont basées sur la réaction de maléimide-thiol, produisant des adduits, qui sont instables dans le sang. Ce travail se concentre sur les approches chimiques pour la fonctionnalisation fiable des anticorps, qui permettent la préparation d'ACs stables présentant un ratio anticorps/principe actif bien défini. La première partie est consacrée à la conception et au développement du réactif maléimide-dioxane, solution auto-hydrolysable et stable dans le sérum, comme alternative à la chimie classique du maléimide. La deuxième partie est consacrée à l'évaluation de la réactivité sélective des différents acides aminés portés par les anticorps par spectrométrie de masse native à haute résolution. Finalement, une nouvelle technologie permettant d’obtenir des ACs stables avec un ratio anticorps/principe actif contrôlé est présentée au lecteur dans une 3ème partie. / Within the last decade, antibodies conjugated to cytotoxic drugs or oligonucleotides have gained a great attention in scientific community owing to the unique properties of the antibodies, such as their long circulation time in serum and high selectivity against their target. For instance, antibody conjugates (ACs) are increasingly applied for targeted cancer therapy or bioimaging. Consequently, the development of reliable methodologies for ACs preparation is currently of high demand. However, the controllable conjugation and preparation of ACs with defined structure are still challenging due to high excess and variety of reactive groups in antibody structure, which are accessible for conjugation. Moreover, current linker technologies are based on the maleimide-thiol reaction, yielding adducts, which are unstable during circulation in blood.This work is focused on chemical approaches for the reliable antibody functionalisation, which enable the preparation of stable ACs with well-defined payload to antibody ratios. The first part is devoted to design and development of maleimide-dioxane reagents as self-hydrolysable and serum-stable alternative to classical maleimide chemistry. The second part is dedicated to a screening approach for evaluation of residue-selective functionalities in reactions with an antibody using high resolution native mass spectrometry. Finally, in the third part the reader is introduced with a novel technology, which enables efficient preparation of stable ACs with a defined degree of conjugation and particularly mono-functionalisation of antibodies.
29

Essential oil components encapsulated in mesoporous silica supports: a bioactive properties evaluation and toxicological approach

Acosta Romero, Carolina 29 March 2018 (has links)
The present PhD thesis, entitled: "Essential oil components encapsulated in mesoporous silica supports: a bioactive properties evaluation and a toxicological approach" focuses on the study of protection and controlled release of natural bioactive agents, derived from essential oil components (EOCs), encapsulated in mesoporous silica particles (MSPs). In addition, this thesis evaluatesthe silica-based supports to reduceundesirable sensorial propertiesandfor ensuring a low-health risk. The first section of the thesis shows the effect of encapsulation of EOCs in mesoporous silica supports. This study evaluates the efficiency of free and encapsulated EOCs to reduce the viability of cancer colon cell lines. This sectionalso shows the selectivity of encapsulated EOCs against cancer linesandtheir effect onnormal (non-cancer) colon cells. Results indicate that EOCs effect can be enhanced and sustained in time when EOCs are encapsulated. Moreover, EOCs' encapsulation shows promising specificity indices, reaching to double effect on colon cancer cells above normal cells. On the other hand,the encapsulation supports and their surface functionalization allows the odour masking of high volatility EOCs. Therefore, the delivery system based on MSPs represents an excellent alternative to promote controlled EOCs release, taking advance of their bioactive properties and solving the technical disadvantages related to volatility and unpleasant odours. Finally, samples used for garlic components encapsulation were immobilised in nanofibers to provide homogeneous and easy-to-handle hybrid system for controlling delivery.The developed 'composite' has potential applications on food, pharmacology, medical or engineering fields. The second sectionof the thesis evaluates the toxicity of the mesoporous silica supports through in vitro and in vivo assessments. Cell viability allows to identify the cytotoxic impact based on the kind of silica-based support, and their features (doses range, size and surface structure changes). Furthermore, the use of Caednorhabditis elegansmodel,shows the in vivo effects afterMSPs ingestion. The toxicological study confirms that size and surface structure, are decisiveMSPs' featuresfor reducing the toxicity risks for health. In summary, the present thesis evaluates the mesoporous silica-based particles as supports for EOCs encapsulation and identifies the main MSPs' features forreducingthe health-toxicity impact. Results of this thesis show that MSPs improve the EOCs activity and help to solve technical problemsof EOCs' volatility.Moreover, these results open up a suitable and safety option for oral delivery devices. / La presente tesis titulada: "Componentes de aceites esenciales encapsulados en soportes mesoporosos de sílice: una evaluación de sus propiedades bioactivas y un enfoque toxicológico" se centra enla evaluación de las propiedades funcionales y organolépticas de agentes naturales bioactivos, derivados de componentes de aceites esenciales, encapsulados en materiales mesoporosos de sílice; a la vez que evalua la toxicidad de los soportes utilizados,con el fin de proponer nuevos sistemas de liberación controlada por vía oral. La primera sección de esta tesis muestra el efecto de la encapsulación de los compuestos de aceites esenciales (EOCs, por sus siglas en inglés) en soportes mesoporosos de sílice. Por un lado, seevalúa la eficiencia de los EOCs libres y encapsulados para reducir la viabilidad en líneas celulares de cáncer de colon. Además, se evalúa la selectividad de los EOCs frente a células de colon normales (líneas no tumorales). Por otro lado, seestudia la capacidad de enmascaramiento de olor de los soportes. Los resultados obtenidos, evidencian en primer lugar, que los EOCs encapsulados mejoran su actividad frente a células de cáncer,en comparacióncon la respuesta de los compuestos sin encapsular. La encapsulación hace que el efecto de los EOCs sea sostenido en el tiempo, y muestra índices de especificidad prometedores, cuandose evalua el efecto toxico de los EOCsfrente a células de cáncer de colon y células normales. Los resultados de esta primera sección, indican que los soportes basados en partículas de sílice mesoporosa (MSPs, por sus siglas en inglés) protegen y liberan eficientemente los compuestos, sino que, a la vez que la funcionalización de la superficie de las MSPs permite enmascarar el olor de los compuestos de mayor volatilidad, y con mayores inconvenientes a nivel sensorial (p.e. compuestos derivados del ajo). Por lo tanto, el sistema de encapsulación se plantea como una excelente alternativa para (i) promover la liberación controlada de EOCs, (ii) aprovechar y mejorar el efecto de sus propiedades bioactivas en células de cáncer de colón y (iii) controlar las desventajas técnicas relacionadas con la volatilidad y limitaciones organolepticas. Por último, se ha comprobado que los soportes empleados en la encapsulación de los compuestos derivados de ajo, mantienen su funcionalidad luego der ser inmovilizados en nanofribras de nylon.Con esto, se busca desarrollar un nuevo sistema de 'composite';un material híbrido y homogéneo, fácil de manejar, que libera controladamente los compuestos encapsulados desde soportes tipo fibras (composites).Estoexpande el abanico de aplicaciones de los EOCs en laindustria alimentaria y farmacológica. La segunda sección de esta tesis, evalúa la toxicidad de los soportes de sílice mesoporosa (MSPs) mediante ensayos in vitro e in vivo. En primer lugar, la viabilidad celular permite identificar el impacto citotóxico de los MSPs sobre líneas celulares de colón. En particular, se evalúa los soportes mesoporosos de sílice, tipo MCM41, en función de (i) las dosis empleadas, (ii) la diferencia de tamaño (micro y nanopartículas) y (iii) el efecto que la funcionalización de la superficie genera en la viabilidad celular. Por otro lado, empleando el modelo Caednorhabditis elegans, yadministrando por vía oral las MSPs,se evalua la influencia de las características de laspartículas (MSPs) en función de la esperanza de vida (lifespan) y la calidad con la que viven y envejecen (healthspan) los nematodos. Los resultados de este estudio,muestran que el tamaño y la estructura de la superficie de las partículas, son parámetros determinantesal momento de diseñar soportes de bajoriesgo toxicológico. En resumen, la presente tesis ha evaluado las características de la sílice mesoporosa, micro y nanoparticulada, como soporte de encapsulación para mejorar la actividad y las aplicaciones de los compuestos de aceites esenciales, al mismo tiempo / La present tesi titulada: "Components d'olis essencials encapsulats en suports mesoporosos de sílica: una avaluació de les seves propietats bioactives i un enfocament toxicològic" se centra en estudis de protecció i alliberament controlat d'agents naturals bioactius, derivats de components d'olis essencials, encapsulats en materials mesoporosos de sílica. Els components d'olis essencials encapsulats milloren les seves propietats funcionals i redueixen els problemes sensorials per aplicacions futures, garantint, al mateix temps, la baixa toxicitat dels suports desenvolupats. La primera secció de la tesi mostra l'efecte d'encapsulació dels components d'olis essencials (EOCs, per les seves sigles en anglès) en suports mesoporosos de sílica sobre la millora de les seues propietats bioactives i el camuflament de problemes sensorials. Este estudi avalua l'eficiència dels EOCs lliures i encapsulats per a reduir la viabilitat en línies cel¿lulars de càncer còlon. A més, la selectivitat dels EOCs es va provar enfront de cèl¿lules de còlon normals (no canceroses). Els resultats han demostrat que l'efecte dels EOCs pot ser millorat i sostingut en el temps quan els EOCs estan encapsulats. Encara més, l'encapsulació dels EOCs mostra índexs d'especificitat prometedors, arribant a duplicar la toxicitat en l'efecte en les cèl¿lules de càncer de còlon amb comparacio en les cèl¿lules normals. Els resultats també mostren que els suports basats en partícules de sílice mesoporoses (MSPs, per les seves sigles en anglès) no sols protegixen i alliberen EOCs eficientment, sinó que, a més, la funcionlització en superfície de les MSPs permet emmascarar l'olor dels EOCs d'alta volatilitat, que té una aplicació limitada a causa dels seus problemes sensorials(p.e. compostos derivats de l'all). Per tant, el sistema de subministrament proposat resulta una excel¿lent alternativa per a (i) promoure l'alliberament controlat de EOCs, (ii) avançant en les seues propietats bioactives en cel¿lulas de càncer còlon i (iii) controlant els desavantatges tècnics relacionats amb la volatilitat i la disseminació desagradable de les olors. Finalmet, les mostres utilitzades per encapsulació de compostos d'all es van immobilitzar en nanofibres per a proporcionar un sistema híbrid homogeni i fàcil de manejar amb administració controlada i característiques bioactives, per aplicacions potencials en l'àrea d'alimentació, farmacologia, medicina o enginyeria. La segona secció avalua la toxicitat del suports de sílice mesoporosa per mitjà d'avaluacions in vitro e in vivo. La viabilitat cel¿lular permet identificar l'impacte citotòxic basat en el tipus de suport base de sílice i les seues característiques (rang de dosi, grandària i canvis en l'estructura superficial).A més, utilitzant el model in vivo Caednorhabditis elegants, s'ha estudiat la influència de les característiques de la sílice mesoporosa, administrant micro i nanopartícules de base sílice, no sols en l'esperança de vida, sinó també en el comportament dels nematodes durant el seu envelliment. Aquest estudi ha demostrat que la grandària i l'estructura superficial, són decisius per a reduir el risc de toxicitat dels suports de sílice mesoporosa i obrir la possibilitat d'utilitzar estos materials en aplicacions d'ingesta oral. En resum, la present tesi ha avaluat les característiques de les partícules de sílice mesoporosa, com a suports d'encapsulació per a millorar l'activitat i les aplicacions dels EOCs, alhora que es va avaluar el seu principal risc tòxicologic. En conseqüència, els resultats obrin una opció adequada i de seguretat per als dispositius d'administració oral. / Acosta Romero, C. (2017). Essential oil components encapsulated in mesoporous silica supports: a bioactive properties evaluation and toxicological approach [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90653 / TESIS
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Transition metal catalysed C-C bond formation via C-H functionalisation

Truscott, Fiona Rosemary January 2012 (has links)
The functionalisation of C-H bonds has been widely studied in organic synthesis. This work presents the results of investigation into two areas of current research, copper-catalysed aromatic C-H functionalisation and rhodium-catalysed hydroacylation. Chapter 1 presents the development of palladium- and copper-catalysed aromatic C-H functionalisation with particular attention paid to regiocontrol. Chapter 2 describes the development of copper-catalysed cross-coupling of perfluorinated arenes and alkenyl halides along with efforts to expand this methodology to a more general reaction. In Chapter 3 the development of chelation-controlled rhodium-catalysed hydroacylation is discussed. Chapter 4 outlines the utilisation of amino acid derived N-methylthiomethyl aldehydes in rhodium-catalysed hydroacylation methodology.

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