Tesi sul tema "A-540"
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Haugsten, Hansen Thomas. "Offshore Wind Farm Layouts : Performance Comparison for a 540 MW Offshore Wind Farm". Thesis, Norwegian University of Science and Technology, Department of Electrical Power Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9990.
Testo completoThis master thesis has been written at the Department of Electric Power Engineering at the Norwegian University of Science and Technology. The work has been carried out at the Royal Institute of Technology in Stockholm, where the author spent the last year of his studies as an exchange student. In the thesis, six different designs of the electrical grid of a 540 MW offshore wind farm, placed 100km off the Norwegian coast, have been studied and compared. At this distance, AC cable transmission might be difficult because of the reactive power production in the cables. Taking this into consideration, two options for the transmission system to shore have been studied. In addition to the AC cable transmission, voltage source converter based HVDC transmission, in the form of HVDC Light, has been studied, giving a total of 12 models. The main scope of the thesis was to study the load flow situation and power system performance of the different offshore wind farm layouts. Two load flow cases were run for each model; the first studying the model when the active power transmission to shore was maximized, the second studying the model under a contingency situation. The reliability of the six designs was compared by calculating the expected number of cable failures during the life time of the wind farm for each design, and what consequence the disconnection of any cable would have on the power losses. In order to study the effect of the offshore grid design and transmission system design on the offshore power system stability, dynamic simulations have also been executed, and the voltage response and rotor speed response following a fault have been studied. All simulations have been executed in version 31 of the program PSS/E. The wind farm was modeled full scale, consisting of 108 wind turbines rated at 5MW. The wind turbines were modeled as doubly fed induction generators, using the generic wind model that comes with the program. The load flow simulations showed that an AC cable connection to shore gave lower total system losses than a DC connection for all designs. The lowest losses were found at the n-sided ring design in the AC/AC system, and the highest losses were found for the star design in the AC/DC system. These losses were 2.33% and 8.19% of the total installed capacity, respectively. In the dynamic simulations, a three phase short circuit fault, lasting 150ms, was applied at three different places in the system. The simulations showed that except from at the wind turbines that were islanded as a result of a fault, all dynamic responses were stable. The HVDC Light transmission to shore gave the highest voltage drops and the lowest voltage peaks offshore. Also, the maximum speed deviation was found to be larger when using HVDC Light transmission compared to using AC cables, with two exceptions; the radial and star designs when a fault was applied to the transmission system. A comparison of the six different grid designs showed that the results were varying. Based on the results in this thesis it has not been concluded that one of the offshore designs have better dynamic qualities than the other. The simulation results indicated that this is case specific, and more dependent on where in the offshore grid the fault occurs rather than the design of the offshore grid.
Siebert, Torsten Uwe. "Four-wave mixing techniques applied to the investigation of non-adiabatic dynamics in polyatomic molecules". Doctoral thesis, [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=966017331.
Testo completoCanadell, Ayats Judit. "Synthesis of polymers with combined flame retardance and low shrinkage properties". Doctoral thesis, Universitat Rovira i Virgili, 2007. http://hdl.handle.net/10803/9016.
Testo completoEn aquests darrers anys s'han desenvolupat diferents estratègies per minimitzar la inflamabilitat dels materials polimèrics, com són la incorporació d'additius o la modificació de l'estructura química dels polímers comercials i la síntesis de polímers específics. La primera opció, àmpliament utilitzada en la indústria per raons econòmiques, presenta alguns inconvenients, ja que els additius es poden extreure amb aigua o dissolvents, poden migrar i poden disminuir les propietats físiques i químiques del material. La incorporació de l'element químic responsable de la resistència al foc, de forma que estigui químicament enllaçat al polímer, permet solucionar part dels problemes abans mencionats per als additius.
Tot i que en aquests últims anys hi ha hagut un increment en el nombre d'heteroelements utilitzats com a retardants a la flama, el mercat està encara dominat per compostos halogenats. Aquests compostos que són altament efectius, interferint amb les reaccions responsables de la propagació de la flama, presenten com a greu inconvenient que durant la seva combustió es desprenen gasos molt tòxics i corrosius. Per aquest motiu, s'estan fent molts esforços en el camp de la investigació en la cerca de nous retardants a la flama lliures d'halògens, que siguin més respectuosos amb el medi ambient i menys agressius en cas d'un incendi. Els compostos fosforats i sililats han demostrat ser efectius retardants a la flama més respectuosos ambientalment.
Un altre problema dels materials polimèrics és l'encongiment que pateixen durant la polimerització i el curat, que té conseqüències negatives en el producte final. Per exemple, en polímers que s'utilitzen com adhesius, es poden trobar zones amb menor capacitat d'adhesió al substrat. Quan s'utilitzen com a recubriments es poden produir tensions internes que poden generar esquerdes i cavitats en el material, reduint la seva durabilitat. En l'actualitat, aquesta problemàtica s'està minimitzant incorporant càrregues, però aquesta metòdica presenta alguns inconvenients ja que augmenta la viscositat del sistema, dificultant el processat i condueix a materials més rígids i fràgils. Una alternativa és utilitzar el que es coneix com a "monòmers expandibles", és a dir, aquells que durant el procés de curat no sofreixen contracció o que fins i tot s'expandeixen lleugerament. Entre els monòmers expandibles més utilitzats es troben els espiroortoesters.
Amb aquests antecedents, el que es va proposar en aquest treball és l'obtenció de nous materials ignifugants, lliures d'halògens, que presentin un baix encongiment durant la polimerització i el curat. Per assolir aquest objectiu, s'han desenvolupat diferents estratègies que a continuació s'exposen breument:
1. Síntesi de nous monòmers basats en espiroortoesters que continguin fòsfor o silici en la seva estructura. En concret, s'han sintetitzat dos espiroortoesters fosforats, el propanoat de (1,4,6-trioxaespiro [4.4] nonà-2-il)-metil-3-[10-(9,10-dihidro-9-oxa-9-fosfafenantrè-10-òxid-10-il)] i el maleat de bis[(1,4,6-trioxaespiro [4.4] nonà-2-il)-metil 2-[10-(9,10-dihidro-9-oxa-9-fosfafenantrè-10-òxid)] i un de sililat, el propanoat de 1,4,6-trioxaespiro [4.4]-2-nonilmetil 3-trimetil silil. Aquests nous monòmers s'han obtingut amb bons rendiments mitjançant la modificació d'espiroortoesters prèviament sintetitzats en el laboratori a partir d'una reacció d'esterificació o una addició de Michael. Els espiroortoesters precursors s'han obtingut per al mètode tradicional, a partir de la reacció de la -butirolactona i un epòxid.
S'ha estudiat la polimerització i copolimerització d'aquests espiroortoesters amb reïnes epoxi comercials amb triflat d'iterbi com a iniciador.
A més, també s'ha estudiat l'efecte de combinar fòsfor i silici en el mateix material, amb l'objectiu d'investigar un possible sinergisme entre els dos elements.
2. Síntesi de nous polímers linials que continguin fósfor i grups espiroortoester en la cadena lateral, a través de copolimeritzacions radicalàries entre un espiroortoester que conté un grup acrilat en la seva estructura i diferents monòmers fosforats. Aquests nous polímers s'han entrecreuat posteriorment amb triflat d'iterbi com a iniciador catiònic, a través de la doble obertura de l'espiroortoester.
També, s'ha investigat la copolimerització catiònica entre el polímer lineal que conté un espiroortoester en la cadena lateral i diferents mescles de reïnes epoxi. Mitjançant l'ús de reïnes epoxi fosforades, prèviament sintetitzades al laboratori, s'ha introduït fòsfor en el material final, aconseguint així millorar les propietats de retardància a la flama.
3. Finalment, s'ha estudiat un nou mètode de copolimerització d'espiroortoesters amb reïnes epoxi utilitzant radiacions de microones, per tal de reduir el temps de curat, i s'han comparat els resultats amb el mètode d'escalfament convencional.
Over the last few decades, the polymeric materials has been replaced the conventional materials due to the versatility, low density, and their interesting properties. However, they present as an important limitation, their high flammability and in presence of heat and oxygen, they burn easily and rapidly. The problem is not only the destruction of the material but the smoke and toxic gases which are the main causes of hazards in a fire.
In the last years different strategies have been developed to minimize the flammability of polymeric materials, such as the use of additives, the modification of commercial polymers or through the synthesis of specific polymers. The first strategy is the most widely use in the industry because is the most economic way to achieve flame retardancy. Nevertheless, this method has several disadvantages, because the additives have to be used in relatively high concentrations and this may affect the physical and mechanical properties of the material. Also, additives may be leached, or may volatilize from the polymer during service. The alternative strategy is to use reactive flame retardants, where the flame retardant is covalently bonded to the polymer chains.
Although in the last few years there has been an increase of heteroelements used as flame retardants, the commercial market is still dominated by compounds based on halogens. These compounds present exceptional efficiency, interfering with the reactions responsible of flame propagation. However, during the combustion they release toxic and corrosive gases. Because of that, in the last few years has increased the interest in the research of halogen-free based flame retardants, such as phosphorus or silicon based flame retardants, which are more environmentally friendly and less aggressive in a fire.
Another problem of polymeric materials is the shrinkage during polymerization and polymer curing, and the consequences can be presented in many different forms. For example, in polymeric coatings poor adhesion of the substrate can be observed. In cast electrical insulators, polymerization shrinkage can produce internal stress in the polymer, which can reduce the durability of the material as a consequence of the appearance of microvoids and microcracks. The most common way to solve this problem is through the use of fillers, however this method present several problems, such as an increase of the viscosity which make difficult to fill molds. Another more advisable strategy is through the use of "expanding monomers", thus means, that during the polymerization and curing they don't shrink or even can produce some expansion. The spiroorthoesters are one kind of expanding monomers.
The main purpose of this thesis is the obtention of new environmentally flame retardant materials that present low shrinkage during polymerization and polymer curing. Several approaches have been developed to achieve these desired properties:
1. Synthesis of new monomers based on spiroorthoesters that contains phosphorus or silicon in their structure. It has been synthesized two spiroorthoesters with phosphorus, (1,4,6-trioxaspiro-[4.4] nonan-2-yl)-methyl 3-[10-(9,10-dihydro-9-oxa-9-phosphaphenanthrene-10-oxide-10-yl)] propanoate and bis[(1,4,6-trioxaspiro-[4.4] nonan-2-yl)-methyl 2-[10-(9,10-dihydro-9-oxa-9-phosphaphenanthrene-10-oxide-10-yl)] maleate and one with silicon in its structure, the 1,4,6-trioxaspiro [4.4]-2-nonylmethyl 3-trimethylsilyl propanoate. These new spiroorthoesters were synthesized with good yields through the modification of previously synthesized spiroorthoesters by a Michael addition or esterification reaction. The spiroorthoester moiety was obtained from -butirolactone and an epoxide.
These spiroorthoesters were polymerized and copolymerized with epoxy resins with ytterbium triflate as a cationic initiator.
Also, with the aim to investigate the possible synergistic effect between phosphorus and silicon were both combined into the same material.
2. Synthesis of linear polymers which contains phosphorus and spiroorthoester moieties in the side chain. They were obtained by radical polymerization from an acrylate-containing spiroorthoesters and different radically polymerizable phosphorus-containing comonomers. The polymers were crosslinked by a cationic double ring-opening of the spiroorthoester moieties with ytterbium triflate as an initiator.
Also, it was studied the cationic copolymerization of a linear polymer which contains a spiroorthoester moiety in the side chain with different epoxy resins. Through the use of phosphorus-containing glycidyl derivatives it was introduced phosphorus into the material.
3. It was studied a new method of copolymerization of spiroorthoesters with epoxy resins using microwave irradiation with the purpose to minimize the curing time. The results were compared with conventional heating conditions.
Reinsch, Martin. "Entwicklung von Analyseverfahren zur Bestimmung von Ochratoxin A in Lebensmitteln". Doctoral thesis, [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980847982.
Testo completoBurýšek, Jan. "Navrhněte řešení spalování s vysokou účinností a nízkou emisí NOx pro granulační parní kotel,130 t/h,s parametry páry 13,6 MPa,540°C". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231269.
Testo completoFache, Maxence. "Fonctionnalisation et polymérisation de dérivés phénoliques naturels : Vers des matériaux aromatiques biosourcés Vanillin, a key-intermediate of biobased polymers Vanillin, a promising biobased building-block for monomer synthesis Biobased epoxy thermosets from vanillin-derived oligomers Amine hardeners and epoxy cross-linker from aromatic renewable resources Epoxy thermosets from model mixtures of the lignin-tovanillin process". Thesis, Montpellier, Ecole nationale supérieure de chimie, 2015. http://www.theses.fr/2015ENCM0014.
Testo completoThe background of this work is the synthesis of bio-based polymers, a very active area of research. Epoxy thermosets were chosen as target because of the double problematic of bisphenol A substitution and of renewable resources use. Thus, the aim of this work is to prepare bio-based epoxy thermosets and to evaluate their potential as substitutes of current formulations. In order to display good thermo-mechanical properties, these polymers have to be prepared from renewable aromatics. Indeed, aromatic cycles bring rigidity and thermal stability to the network. Vanillin is one of the only aromatic molecules available from biomass at an industrial scale. It is obtained from the alkaline oxidative depolymerization of lignin. Recently, the preparation of renewable polymers from vanillin has been intensively explored; a review on this subject was compiled. Vanillin served as a building-block to prepare a platform of derivatives bearing various functions. Di-amine, di-epoxy, or di-(cyclic carbonate) monomers – among others – were synthesized. The di-epoxy monomers prepared were cross-linked with a common amine hardener and the polymers obtained were characterized. Their thermo-mechanical properties were linked to the monomers structure. These potentially bio-based epoxy thermosets have properties comparable to the bisphenol A-based reference. In order to tune these properties, vanillin-based epoxy oligomers were synthesized by the same method as the one used industrially. The properties of these oligomers and of the thermosets prepared from them could indeed be modulated. Other means of controlling the properties were tested, like the preparation and polymerization of new bio-based amine hardeners, or of a vanillin-based, tri-functional epoxy monomer. The thermoset prepared from this last compound displayed better properties than the bisphenol A-based reference. Finally, a work more centered on the resource was performed. Mixtures of phenolic compounds modelling the products of the lignin-to-vanillin process were prepared. The use of such mixtures instead of pure vanillin could be advantageous both from an economic and an ecologic point of view. These mixtures were glycidylated, polymerized, and the materials obtained were characterized. The excellent properties displayed by these materials allow a potential integration of this strategy in a bio-refinery
Tasso, Mariana Patricia. "Bioactive coatings to control marine biofouling". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-25187.
Testo completoRulliere, Pauline. "Vers la synthèse totale de la (-)-salinosporamide A et de la (+)-lactacystine par cycloaddition [2+2] asymétrique". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENV023/document.
Testo completoThis thesis work focuses on the [2+2] asymmetric cycloaddition of ketenes and its application in total synthesis. The best reactivity of Z olefins compared to E olefins, one of the features of the [2+2] cycloaddition, is studied both from a synthetic and theoretically point of view, via DFT calculations. A methodology of [2+2] asymmetric cycloaddition between chiral enol ethers and various in situ generated ketenes was then developed. Cycloadditions limited to the use of dichloroketene hitherto was extended to a wide range of ketenes, leading to various highly functionalized cyclobutanones. Those chiral cyclobutanones were engaged in the total synthesis of natural products: lactacystin and salinosporamide A, proteasome inhibitors and potent anticancer agent. These syntheses have three common key steps : a [2+2] asymmetric cycloaddition, a Beckmann type ring expansion and a side chains functionalization. The formal synthesis of lactacystin is presented in this manuscript, as well as the work in progress towards the synthesis of salinosporamide A
Mercado, Roca Luis Adolfo. "Resinas epoxi sililadas retardantes a la llama. Síntesis, caracterización y propiedades". Doctoral thesis, Universitat Rovira i Virgili, 2005. http://hdl.handle.net/10803/9002.
Testo completoEn los últimos años se han descrito algunas aproximaciones sobre resinas epoxi con silicio unido covalentemente a la matriz polimérica. Así, han sido descritas modificaciones sobre resinas epoxi comerciales y copolimerizaciones de monómeros glicidílicos que contienen silicio con resinas epoxi comerciales, consiguiéndose una mejora de las propiedades retardantes a la llama sin sacrificar las propiedades mecánicas de la resina curada.
En este trabajo se ha planteado como objetivo general el desarrollo de resinas epoxi basadas en silicio con propiedades retardantes a la llama. Así, se ha llevado a cabo la síntesis de monómeros glicidílicos que contienen silicio en su estructura. Para establecer una relación entre la presencia y proporción del silicio y las propiedades físicas de los materiales resultantes, se han preparado polímeros termoestables a partir de mezclas de un glicidilo comercial con los monómeros que contienen silicio así como prepolímeros obtenidos a través de reacciones de crecimiento de cadena entre el DGEBA y un silanodiol. También se han sintetizado monómeros y agentes de curado que contienen fósforo en su estructura y se han preparado polímeros termoestables que contengan ambos heteroátomos. Con objeto de estudiar el mecanismo de reacción de monómeros que contienen silicio con aminas primarias, se ha sintetizado un monómero sililado monofuncional, fenilglicidiloxidimetilsilano (GDMPS), y se ha comparado su reactividad frente a una amina primaria, anilina, con la de un glicidilo comercial, fenilglicidiléter (PGE). El estudio cinético fue llevado a cabo mediante NIR y aplicando a los datos espectrales obtenidos métodos de análisis multivariante de resolución de curvas (MCR-ALS). Se ha llevado a cabo el estudio cinético del curado de un diglicidilo que contiene silicio, fenildiglicidiloximetilsilano (DGPMS), y de las mezclas de éste con DGEBA con una diamina primaria, DDM, mediante DSC isotérmico y dinámico. Además, se han estudiado los fenómenos de gelificacion y vitrificación de estos sistemas mediante DMTA en modo cizalla y TMDSC. Se han preparado polímeros termoestables y se han evaluado sus propiedades termodinamomecánicas, térmicas y de retardancia a la llama. Las propiedades termodinamomecánicas han sido estudiadas mediante DMTA en modo de flexión. La estabilidad térmica de estos compuestos se ha estudiado mediante análisis termogravimétrico en atmósfera de nitrógeno y de aire. Las propiedades de retardancia a la llama fueron evaluadas mediante el test ASTM-D-2683 del índice de oxígeno limitante (LOI). Finalmente, se ha estudiado la degradación térmica de los polímeros obtenidos para establecer el modo de actuación del silicio durante la degradación. Para ello, se ha realizado el estudio cinético de la degradación a partir datos obtenidos por TGA, estudios de las etapas iniciales de la degradación mediante quimioluminiscencia (QL) y la caracterización de los productos formados por TGA-MS, GC-MS, ATR-FTIR y DRX.
De los resultados obtenidos se han podido establecer las siguientes conclusiones: (1) Se ha determinado que la presencia del silicio produce un aumento en la reactividad del epóxido probablemente debido a efectos electrónicos. Esta mayor reactividad además reduce la importancia del camino autocatalítico en el curado con aminas primarias. (2) Las resinas epoxi sililadas termoestables muestran una disminución de la Tg y de la densidad de entrecruzamiento con el incremento del porcentaje de silicio.
Esta disminución está relacionada con un aumento del volumen libre debido a la mayor longitud de los enlaces Si-O. (3) Los polímeros termoestables que contienen silicio muestran un incremento del LOI a partir de un contenido de silicio del 3%. En los polímeros que contienen silicio y fósforo, se encontraron evidencias de la existencia de sinergia entre los dos heteroátomos. (4) La degradación de los polímeros que contienen silicio, tanto en atmósfera inerte como oxidante, conlleva la formación de oligómeros cíclicos de fenilmetilsiloxano, lo que implica que parte del silicio abandona la fase condensada. El residuo contiene silicio como SiO2, formando probablemente una capa aislante que actúa como barrera térmica y de transferencia de masa disminuyendo de esta manera la producción de volátiles.
The epoxy resins are widely used in coatings, adhesives, composites, etc. In some applications of epoxy resins special and versatile features are required, such as high adhesion to the substrates, low shrinkage, low thermal stress after curing, toughness, chemical resistance and low flammability. The flammability of epoxy resins is the main drawback in their application. Some flame retardants compounds, such as brominebased compounds, antimony oxides, phosphorous-halogen compounds etc. are incorporated in the epoxy resins to reduce their flammability. These compounds are exceptionally efficient but they have the inconvenience that they increase the smoke and toxic and corrosive gas evolution during the combustion of the polymer. For these drawbacks in the last years it has been increased the investigation of other heteroatoms like flame retardants to replace the halogens.
Some approaches about epoxy resins with silicon covalently bonded to the polymeric matrix have been reported. In this way, modifications of commercial epoxy resins and copolymerizations of silicon-based monomers with commercial epoxy resins giving to good flame retardancy, thermal and mechanical properties have been reported.
The aim of this thesis is the development of novel fire retardant silicon-based epoxy resins. Glycidyl monomers with silicon in their structure, prepolymers obtained by mean of growth of chain reactions between diphenyl silanediol and diglycidylether of bisphenol A (DGEBA) and a phosphorous-containing glycidyl monomer and two phosphorilated diamines were synthesized. Thermoset polymers were obtained from curing reactions of the compounds synthesized. To study the reaction kinetics of silicon-containing epoxy monomer with primary amines, a monofunctional silicon-containing epoxy monomer has been sinthesized, glycidyloxydimethylphenyl silane (GDMPS), and its reactivity with a primary amine, aniline, has been compared with that of a commercial epoxy monomer, phenylglycidylether (PGE). Kinetics studies were carried out by Near Infrared Spectroscopy (NIR) and applying to the spectral data obtained the multivariate resolution of curves methods. Likewise, the kinetic and curing behaviour studies for the difunctional silicon-containing epoxy monomer, diglycidyloxyphenylmethyl silane (DGPMS), and the mixtures of this monomer with DGEBA with a primary diamine, 4,4'- diaminediphenylmethane (DDM), have been carried out by means of isothermal and dynamic DSC. The gelation and vitrification for these systems have been studied by thermodinamechanical analysis (DMTA) with a shear sandwich clamp and modulated temperature differential scanning calorimetry (TMDSC).
The relationship between the amount of silicon and the thermodinamomechanical, thermal and flame retardancy properties of the thermoset materials obtained have been established. Thermoset materials were obtained from mixtures of commercial glycidyl monomer, DGEBA, with a silicon-containing glycidyl monomer, diglycidyloxyphenylmethyl silane (DGPMS), and their properties have been evaluated.
Thermodinamomechanical properties have been evaluated by DMTA using a 3-point bending clamp. The thermal stability have been analyzed by thermogravimetric analysis (TGA) in nitrogen and air atmospheres. The flame retardant properties have been evaluated by means of ASTM-D-2683, the limiting oxygen index test (LOI).
Finally, the thermal degradation of the silicon-containing polymers has been investigated by means of chemiluminiscence (CL), TGA-MS, GC-MS, ATR-FTIR and
DRX.
From the results obtained the following conclusions can be infered: (1) The silicon occurrence increases the reactivity of the epoxide due to electronic effects. This higher reactivity also reduces the importance of the autocatalytic path in the curing reactions with primary amines. (2) The thermoset epoxy resins showed a decrease in the Tg and the crosslinking density when the amount of silicon increases. This decrease is related with an increase of the free volume due to the Si-O and Si-C bonds. (3) The siliconcontaining thermosets show an increment of the LOI for silicon contents higher than 3%. In the polymers that contain silicon and phosphorous, there are evidences of the synergyc effect. (4) During the degradation of the silicon-containing materials in both, nitrogen and air atmospheres, cyclic siloxane oligomers were released. A silicon oxide rich char is formed, probably forming an insulating layer.
Agarwal, Sameer. "Transition Metal-Mediated Syntheses of Yohimbane and Indolizidine Alkaloids". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1119360417222-39155.
Testo completoBürgel, Christian. "Functionality of noble-metal clusters". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/15887.
Testo completoIn this thesis, the unique novel properties of noble metal clusters which arise in the sub-nanometer size regime due to quantum confinement have been theoretically explored. It has been demonstrated that by adding or removing a single atom the chemical and physical properties and functionality of noble-metal clusters can strongly change. The theoretical results have been derived in close cooperation with experimental findings of partner groups demonstrating that by joint theoretical and experimental efforts thorough understanding of fundamental processes and underlying mechanisms can be achieved. This thesis addresses the reactivity of charged gas-phase gold-oxide clusters in the context of the heterogeneous gold nano-catalysis, the ultrafast dynamical properties of noble-metal clusters and their complexes, and the optical properties of silver clusters at surfaces.
Vu, Duc Nam. "Catalytic cleavage of vegetable oil derivatives to aldehydes and other bio-based building blocks". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1259.
Testo completoAldehydes are important chemicals in organic synthesis, due to their vast applications in cosmetics, pharmaceuticals and herbicides. Moreover, they can be converted to value-added compounds such as surfactants, polymers, etc. Conventionally, aldehydes are produced through hydroformylation or reductive ozonolysis of alkenes. However, both methods suffer from the use of expensive catalyst and sophisticated ligands (hydroformylation) or the requirement of high energy intensive process (ozonolysis). As a result, the development of more sustainable approaches for the production of aldehydes is highly desirable.In this context, we have developed two methods to produce aldehydes from unsaturated fatty acid derivatives. The first route involves the preparation of fatty a-hydroxyketones from 1,2-diols and their cleavage to give aldehydes with good yields. In this route, two catalytic systems (metal-based homogeneous and heterogeneous) have been developed to oxidize vicinal diols to corresponding a-hydroxyketones. The cleavage of these species has been carried out through a retro-benzoin process using thermally stable thiazolium salts and the aldehydes were recovered by reactive distillation. The second route relies on the decomposition of fatty ß-hydroxy hydroperoxides that are easily prepared from epoxidized methyl oleate. Moreover, the decomposition of the peroxide species was studied under thermal conditions to give aldehydes. Finally, the cleavage of fatty 1,2-diketones and the valorization of aldehydes were also studied to give the corresponding esters that could be used as monomers
Martín, Moreno Cristina. "Síntesis de polímeros organoborados retardantes a la llama". Doctoral thesis, Universitat Rovira i Virgili, 2005. http://hdl.handle.net/10803/9001.
Testo completosintéticos ha aumentado de forma importante debido a la multitud de aplicaciones, pero la
mayoría de ellos son extremadamente inflamables y en presencia de una fuente de calor y de xígeno se queman fácil y rápidamente.
La estrategia comúnmente más utilizada para minimizar la inflamabilidad de un
material, es la incorporación de sustancias retardamtes a la llama. Aunque en los últimos años ha habido un incremento en el número de heteroelementos utilizados en compuestos
retardantes a la llama, el mercado está todavía dominado por compuestos que contienen
halógenos, especialmente cloro y bromo. Estos compuestos, son muy efectivos ya sea como
aditivos o como reactivos pero presentan un inconveniente importante: incrementan las
cantidades de humos y productos de descomposición tóxicos que se desprenden durante la
combustión del polímero. Es por ello, que cada vez más se están dedicando grandes esfuerzos en investigación a la búsqueda de nuevos retardantes a la llama libres de halógenos, que
respeten el medio ambiente y no resulten agresivos.
El ácido bórico y sus sales han sido empleados como aditivos retardantes a la llama
desde 1800. La mayoría de retardantes a la llama que contienen boro se descomponen
térmicamente generando ácido bórico liberando agua en una reacción endotérmica, por tanto, pueden actuar como retardantes físicos al absorber calor en el proceso de descomposición,
diluir los volátiles en la fase gaseosa o formar una capa de vapor de agua sobre la fase sólida.
Además, el ácido bórico puede actuar formando un recubrimiento intumescente que
incrementa la efectividad de la capa protectora. Estos compuestos de boro son los más
utilizados, ya que resultan baratos y de amplia aplicación, pero presentan, al igual que todos
los aditivos, multiples desventajas frente a los reactivos retardantes a la llama. Los
compuestos organoborados que actúan como reactivos retardantes a la llama, no han sido
estudiados hasta, relativamente, hace poco tiempo, sin embargo, los resultados obtenidos
sobre la retardancia a la llama, en los diferentes polímeros modificados químicamente con
compuestos de boro, han sido satisfactorios.
Como objetivo general de este trabajo, se planteó la obtención de nuevos sistemas
poliméricos termoestables resistentes al fuego, libres de halógenos, sin detrimento de las
propiedades del material y que respeten el medio ambiente. Para ello se sintetizaron y
caracterizaron tres nuevos tipos de sistemas poliméricos basados en:
- Resinas novolaca con boro, obtenidas por modificación química de una resina
novolaca comercial con dos compuestos organoborados: bis(benzo-1,3,2-
dioxaborolanilo) y óxido de bis(4,4,5,5-tetrametil-1,3,2-dioxaborolanilo).
Posteriormente, con la finalidad de mejorar sus propiedades mecánicas, estas resinas
se entrecruzaron con hexametilentetraamina (HMTA) y diglicidil éter de bisfenol A
(DGEBA).
- Resinas epoxi-novolaca modificadas con compuestos organoborados y
posteriormente entrecruzadas térmicamente con catalizador.
- Polímeros estirénicos preparados a partir de monómeros que contienen boro.
Finalmente, se evaluaron las propiedades térmicas, termodinamomecánicas y de
retardancia a la llama de los sistemas anteriormente comentados. Pudiéndose concluir que el entrecruzamiento de las resinas novolaca con HMTA o DGEBA y de las epoxi-novolaca en presencia de un catalizador, permite obtener materiales con una buena integridad mecánica, permitiendo así establecer relaciones cualitativas de niveles de entrecruzamiento. La degradación térmica de las resinas modificadas con boro: resinas novolaca y resinas epoxinovolaca, y de los polímeros estirénicos borados, genera ácido bórico a elevadas temperaturas formando un residuo intumescente que retarda el proceso de degradación y evita que ésta sea total. Las resinas novolaca organoboradas, con contenidos de boro entre 2 y 4%, presentan excelentes propiedades de retardancia a la llama. En cambio, los polímeros estirénicos borados necesitan contenidos de al menos el 3% para manifestar buenas propiedades retardantes a la llama.
Although in the last decade there has been an increase in the number of heteroelements
used in flame retardants, the commercial market is still dominated by compounds containing halogens, notably chlorine and bromine. They are exceptionally efficient and may be incorporated as either additives or as reactives, but they do have such clear disadvantages as the generation of toxic and corrosive gases during thermal degradation. Recent developments in the chemistry of halogen-free flame retardant polymers involve polymers or reactive monomers that are inherently flame retarding such as those containing P, Si, B, N and other miscellaneous elements.
Boric acid and borate salts have been used as flame retardant additives since the early
1800s. Borates are effective flame retardants because impenetrable glass coatings form when they thermally degrade. The glass coatings form on the surface, and can contribute to the intumescent effect, because they exclude oxygen and prevent further propagation of
combustion. The water of hydration is lost by endothermic decomposition and therefore both dilutes and cools, by absorbing the thermal energy from the flame. However, additives have the disadvantage that they have to be used in relatively high concentrations (typically 30% by weight, or more) and this may affect the physical and mechanical properties of the polymers.
Also, additives may be leached, or may volatilise from the polymer during service. The
alternative strategy is to use reactive flame retardants, via copolymerization or some other
type of chemical modification (i.e. flame retardant groups that are inherently part of the
polymer backbone or that are covalently attached as side groups to the polymer).
The main aim of the present thesis is to develop new environment friendly flame
retardant thermosets, which are halogen free and have the good thermal and mechanical
properties of some standard materials. Synthetic approaches introduce boron into the
backbone of various polymers, so this main aim can be divided into four subsidiary aims:
− To synthesize and characterize boron-containing novolac resins obtained by
modifying novolac with organoboron compounds. These polymers were further
crosslinked with HMTA and DGEBA
− To synthesize and characterize epoxy-novolac resins, which are then further modified
with boron
− To synthesize and characterize boron-containing styrene monomers, which are then
further polymerized and copolymerized with styrene
− To evaluate the thermal, mechanical and flame retardancy properties of all the
polymeric systems synthesized
The conclusions drawn from the various studies of the present thesis can be summarized
as follows:
− The modification of the commercial novolac resin with organoboron compound
reaches a plateau at a modification degree of 65%
− The crosslinking of boron-modified novolac resin with HMTA is slower and less
extensive than that of commercial novolac resin because of the nitrogen coordination
from intermediate species with boron
− The crosslinking of commercial novolac resins with DGEBA needs a catalyst to be
added while the crosslinking of boron-containing novolac resins does not because the
boron itself acts as a catalyst
− The epoxy-novolac resins react with boron compounds mainly through the hydroxylic groups from halohydrin and opened glycidylic groups
− The thermal degradation of boron-containing novolac resins, boron-containing epoxynovolac resins and boron-containing styrenic polymers generates boric acid at high
temperatures to give an intumescent char that slows down the degradation and
prevents it from being total
− Novolac resins modified with boron content between 2 and 4%, show high LOI values
(above 38%)
− Boron-containing styrenic polymers show LOI values that increase with boron content
but boron contents need to be above 3% to achieve good flame retardant properties.
Kahle, Ingolf. "Wirt-Gast-Systeme - optische Eigenschaften von Farbstoffen und Metall-Nanopartikel in mikro- und mesoporösen Alumosilikaten". Doctoral thesis, Universitätsbibliothek Chemnitz, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-149319.
Testo completoChrouda, Amani. "Élaboration de nouveaux matériaux d’électrodes modifiées pour application biocapteurs". Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10074.
Testo completoThe objective of the research work was to the development of modified electrode materials for biosensor application. The work was devided into three parts: electrografting of diazonium salt for immunosensor application, electroadressing of antibodies and electrodeposition of PEG spacer for aptasensor application. In the first part of this work, the modification of gold surfaces with nitrobenzene diazonium cation was investigated in order to develop an immunosensors for the detection of Staphylococcus aureus. A detection limit of 10 CFU/mL has been obtained. The second part was focused on the electrically addressable deposition of diazonium functionalized antibodies on boron-doped diamond (BDD) microcells for the detection of OTA. A detection limit of 0.007ng/mL has been obtained and the immunosensor was tested on real samples. Finally, we developed an amperometric aptasensor based on electrochemical grafting of a PEG-COOH spacer on a BDD microcell for the detection of OTA biotoxin. A detection limit of 0.01 ng/L has been obtained and application to a real sample (rice) has been demonstrated. The amperometric and impedimetric techniques used in this work lead to promising results in terms of sensitivity, specificity and reproductibility
Kajahn, Inga. "Kopplungsmethoden in der Naturstoffanalytik : Untersuchungen an Arabidopsis thaliana und an Ancistrocladus-Pflanzen". Doctoral thesis, kostenfrei, 2008. http://www.opus-bayern.de/uni-wuerzburg/volltexte/2008/2728/.
Testo completoPetrelli, Antoine. "Synthèse par chimie click non métallo-catalysée de glycoconjugués macromoléculaires d'interêt médical". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAV043/document.
Testo completoThe aim of the project is to develop new anomeric modification of oligosaccharides for the synthesis of glycoconjugates by metal-free click chemistry. Synthetic glycans have shown a great potential in medical and nanotechnology related fields. The current use of metallic catalyst during synthesis and the risk of contamination of the final product represent a drawback which could restrain their applications. Therefore an efficient metal free synthesis of glycoconjugates could be of great interest to circumvent this obstacle.Two distinct synthetic strategies have been explored for the metal free coupling of complex oligosaccharides on polymers to yield block-copolymers and glycoadsorbants. The glycopolymers were synthetized by a Michael addition between a thiol functionalized oligosaccharide and a maleimide or bromo-maleimide functionalized polymer. The nanoparticles obtained from the self-assembly of theses amphiphilic copolymers in water were characterized. The polycaprolactone-b-xylooligosaccharides copolymers presenting a reducible linkage were self-assembled into nanoparticles and assessed as model for the delivery of hydrophobic drugs. This system showed a selective release of the entrapped molecules in reducing environment making it an interesting system for the intra-tumoral delivery of anti-cancer drugs. Glycoadsorbents were prepared by a Diels Alder reaction between a solid matrix displaying a maleimide moiety and furyl functionalized oligosaccharides. The affinity matrixes obtained allowed the selective purification of lectins. The blood group antigen (A;B) grafted matrixes displayed good properties for the trapping of corresponding anti-A or anti-B antibodies. These types of immunoadsorbants have great potential for the treatment of immune diseases like the Guillain-Barré syndrome.To conclude, two efficient anomeric modification and coupling strategies of oligosaccharides have been developed, opening the way to the metal free synthesis of various glycoconjugates
Jose, Davis. "Dynamics of the B-A transition of DNA double helices". Doctoral thesis, [S.l.] : [s.n.], 2005. http://webdoc.sub.gwdg.de/diss/2005/jose/jose.pdf.
Testo completoGreiner, Rinaldo, Merle Allerdissen, Andreas Voigt e Andreas Richter. "Fluidic microchemomechanical integrated circuits processing chemical information". Royal Society of Chemistry, 2012. https://tud.qucosa.de/id/qucosa%3A27798.
Testo completoDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
Leung, Sik-keung, e 梁錫強. "A study of Liang Wu-di, 464-549". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1989. http://hub.hku.hk/bib/B31949514.
Testo completoDas, Sanjit. "Methodological development in peptide chemistry for synthesis of antimicrobial and antifungal derivatives of marine natural peptides". Thesis, Perpignan, 2018. http://www.theses.fr/2018PERP0054.
Testo completoThe click chemistry has become indispensible in the many areas of chemistry associated with drug design. In this context, as we know the study concerning the impact of triazole insertion on the conformation of peptaibol is limited, we have conducted the study to investigate the impact and adaptability of the 1, 4-disubstituted 1, 2, 3-triazole insertion into different peptaibols. Depending on the outcome of this experiment relating to reduced activity and perturbed conformation of the peptaibol analogue, the dipeptide surrogate decorated with the triazole moiety bearing various hydrophobic substituents was inserted at the very N-ter part of the peptaibol. The improvement of the bioactivity and restoration of the conformation for the peptaibol analogues was observed and the fact was also supported by the results obtained from the biophysical study of the selected analogues of ALM F50/5. We have further extended our study to employ our strategy to be applied on the therapeutic P42 peptide which suffers from the limitation of lack of permeability and stability. P42 peptide is involved in the pathophysiology of neurodegenerative Huntington’s disease. A total of 12 analogues of P42-TAT peptide were synthesized through SPPS by our optimized protocol. In the second part, we have developed a strategy for synthesizing the cyclic lipopeptide originated from marine cynaobacterial species. Our main objective was to synthesize Hormothamnin A, a cyclic undecapeptide consisting of several unnatural amino acids including dehydroamino acid (Dhaa) which makes the synthesis of this peptide complicated. Due to this reason, firstly, we have chosen to apply our strategy to synthesize Trichormamide A, a relatively simpler kind of cylic lipopeptide. After accomplishing this task, a first attempt was made to synthesize Hormothamnin A. The preliminary result of this is presented in this section. At last, we have tried to develop a robust methodology to synthesize Fmoc-Dhaa in solution phase and its insertion into the peptaibol sequence through a standard SPPS protocol. The preliminary results we have got concerning the Dhaa synthesis and its insertion into peptaibol are also discussed here in addition with the solid phase synthesis of natural Bergofungin D
Cuadrench, Tripiana Anna. "Anàlisi i avaluació de l'exposició a les aflatoxines i a l'ocratoxina A, a partir de compost". Doctoral thesis, Universitat Ramon Llull, 2014. http://hdl.handle.net/10803/247964.
Testo completoEn la presente Tesis doctoral se ha valorado el contenido fúngico de un total de 18 muestras de compost: 7 procedentes de la planta de compostaje de Manresa, 6 de la de Blanes, dos procedentes de residuo sólido urbano procesado en la planta de CESPA, Can Barba (Barcelona), dos de compost casero de Pineda de Mar y, finalmente, una procedente de heces de caballo obtenida en un comercio especializado en productos de jardinería. Para cada una de las muestras se ha realizado el cálculo de las unidades formadoras de colonia de hongo, ufc / g; se han identificado los hongos de cada una de las muestras a nivel de género y se han seleccionado los Aspergillus y Penicillium, que se han incubado siguiendo el método de la FDA, para comprobar si pueden producir las aflatoxinas G2, G1, B2, B1 y la OTA. Ninguno de los hongos potencialmente micotoxigénicos aislados ha dado positivo en la producción de las toxinas estudiadas por encima del límite de detección, cuando se han aplicado los métodos cromatográficos descritos en este trabajo. Por este motivo, se estudia si el compost es un sustrato adecuado para la producción de aflatoxinas incubando la cepa de control Aspergillus parasiticus CECT 2681, descrita como productora de aflatoxinas, sobre diferentes proporciones de mezclas de arroz - compost. Tras comprobar que la cepa control no puede producir las toxinas cuando el hongo se desarrolla sobre un 100% de compost, se comprueba si puede seguir haciéndolo sobre arroz. También se comprueba si la cepa control pierde su capacidad micotoxigénica al ser incubada sobre compost y luego sobre arroz. Para realizar este análisis se utiliza un método desarrollado en la sección de UHPLC-UV. Las diferentes pruebas realizadas con la cepa de control Aspergillus parasiticus CECT 2681, concluyen que la cepa control no pierde su capacidad micotoxigénica al ser incubada primero sobre compost y luego sobre arroz. También se puede concluir que el compost no es un buen sustrato para la producción de aflatoxinas ya que la producción de estas disminuye al aumentar la proporción de compost en el sustrato de crecimiento del hongo.
In this doctoral thesis we evaluated the fungal content of a total of 18 compost samples: 7 from the composting plant from Manresa, 6 from Blanes, 2 from urban solid waste from the processing plant CESPA, Can Barba (Vallès Occidental), two from homemade compost from Pineda de Mar and finally, one sample of fecal horse obtained in a trade specialized in gardening products. For each one of the samples the calculation of the fungus colony forming units, cfu / g, has been carried out; fungi have been identified for each of the samples at the level of genera. Aspergillus and Penicillium have been selected and have been incubated following the FDA method to verify if they can produce aflatoxins G2, G1, B2, B1 and OTA. Any of the isolated micotoxigenics fungi has positive production of the studied toxins over the detection limit when we have applied the chromatographic methods described in this work. For this reason, we study if compost is an appropriate substrate to produce aflatoxins by incubating control strain Aspergillus parasiticus CECT 2681, described as a producer of aflatoxins, in different proportions of rice-compost mixtures. After verifying that the control strain cannot produce toxins when the fungus grows on a 100% of compost, we verify if it can continue to produce toxins over the rice. It also verifies if the control strain loses its micotoxigenical capacity when it was incubated over compost and then over rice. To do this analysis we use a UHPLC-UV method developed in our section. To the different analyses realized with control strain Aspergillus parasiticus CECT 2681, we conclude that the strain does not lose its micotoxigenical capacity when being made on first and then incubated over rice. It can also be concluded that the compost is not a good substrate for aflatoxins production because the aflatoxins production decreases when the proportion of compost increases in the growth fungal substrate.
Boyce, Richard J. "Synthetic studies with naturally occurring methylthiazolines and polyene macrolides". Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307842.
Testo completoNewton, Sean. "Spirodienal A and spirangien A : a flow-assisted approach to complex natural product synthesis". Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648096.
Testo completoEl, Fallah Rawa. "Étude des interactions du Benzo(a)pyrène avec les trois fractions physiques de la matière organique du sol par matrices d'excitation et d'émission de fluorescence couplées à PARAFAC". Thesis, Perpignan, 2017. http://www.theses.fr/2017PERP0034/document.
Testo completoThe spectral properties of the fluorescent components of the organic matter of a natural soil were studied in the three physical fractions; humic substances, fulvic acid and humic acid, by the method of the excitation and fluorescence emission matrices coupled to the Parallel Factor Analysis (PARAFAC) algorithm. The spectral modifications of these components were studied (form and pseudo-concentrations) in the presence of a polycyclic aromatic hydrocarbon contaminant (benzo (a) pyrene (BaP), toxic and carcinogenic): (1) by varying the volumes of a pure solution of BaP in each fraction having the same concentration of organic matter, (2) by varying the concentrations of organic matter for fixed concentrations of BaP, which were followed over time. The results showed that the BaP influences the fluorophores present in the three fractions in a different way and clarified the type of interactions with one fraction or the other. On the other hand, a discussion was held on parameters for validating the number of components for the selection of PARAFAC models
Wendling, Gilles. "Lipoprotéine a : étude rétrospective à propos de 543 observations". Bordeaux 2, 1995. http://www.theses.fr/1995BOR2M122.
Testo completoMeneghello, Marta. "A modular approach for a controlled immobilization of enzymes". Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/422233/.
Testo completoTudhope, Stephen Richard. "A rational approach to the design of a leukotriene antagonist". Thesis, University of Surrey, 1987. http://epubs.surrey.ac.uk/848139/.
Testo completoHazelwood, Andrew James. "A new approach of the AB spiroketal of altohyrtin A". Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620304.
Testo completoGallardo, Gonzalez Juan. "Développement d'un laboratoire sur puce pour la détection des amphétamines dans les égouts". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1191/document.
Testo completoThe work in this thesis is devoted to the development of an autarkic device for real-time monitoring of amphetamines in sewage. It has been developed within the EU project Micromole to help Law Enforcement Agents (LEA) to solve forensic scenarios related to the production of amphetamines and amphetamine-type stimulants (ATS). It is composed of three main sections. The first section is devoted to the development of two generation of potentiometric sensors for the detection of amphetamines using first, the commercial ionophore dibenzo-18-crown-6 ether, then the synthesized ion-pair complex [amphetamine-H]+[3,3’-Co(1,2-C2B9H11)2]- as active sites for amphetamine recognition. The second section is dedicated to the fabrication of a passive microfluidic system integrated into a Lab-on-a-Chip to protect the sensor from the harsh environment through the control of the sample amount reaching the sensor. For this purpose, the microfluidic system formed a combination of passive micromixers, microfilters and microchannels. The final section was devoted to the development of an autarkic sample storage unit to help LEA to store spontaneous samples during forensic investigations related to the clandestine production of amphetamines in illegal laboratories
Di, Francesco Maria Emilia. "Total synthesis of a fully protected Seco-acid of peloruside A". Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616231.
Testo completoDogan, Fatma. "Development of a nanopore-based biosensor embedded into a microfluidic channel". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/30709.
Testo completoGauntlett, Carolyn. "Cascade strategies for chemical synthesis : towards a total synthesis of nakadomarin A". Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612075.
Testo completoBriant, Rémi. "Développement de nouvelles séries d’inhibiteurs hétérocycliques des protéines kinases : synthèse, relations structure-activité et optimisation de leur sélectivité au sein du groupe CMGC". Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10256.
Testo completoSince the approval of imatinib (or Gleevec®), protein kinases have become major targets for the treatment of several pathologies (cancer, neurodegenerative diseases,…). Among the eight existing groups of protein kinases, the CMGC group consists of 61 serine-threonine kinases classified as CDKs (cyclin-dependent kinases), GSK3 (glycogen synthase kinases), CLKs (Cdc2-like kinases), DYRKs (dual specificity, tyrosine phosphorylationregulated kinases) or other sub-families. Nevertheless a major challenge remains concerning the development of kinase-modulating small molecules: the selectivity of these new inhibitors, which generally bind in the ATPbinding pocket, a common site for all protein kinases. Our team aims at synthesizing original and selective inhibitors of CMGC kinases. In this presentation, we are introducing the synthesis, the evaluation of the structure-activity relationships and the optimization of the selectivity of three series of heterocyclic inhibitors, targeting CMGC protein kinases. Based on N-&-N1 (GP0210), an inhibitor developed in the laboratory and currently in preclinical trials, the synthesis and the biological evaluation of a library of pyrazolo[1,5-a]triazines led to the identification of two series of compounds which inhibit CDK on the one hand and GSK3 on the other hand. From AT7519, a CDK and GSK3 inhibitor currently in phase II clinical trials in oncology, we synthesized new pyrazole-3-carboxamides, which are selective GSK3 inhibitors and may have different therapeutical applications. Finally we prepared derivatives of meriolines, CDK inhibitors that have been previously developed in our laboratory. These new compounds inhibit CLKs on the nanomolar scale and are selective against other CMGC kinases, especially against DYRKs. This last result has never been obtained so far
Webb, Damien. "Lyngbouilloside : a synthetic study". Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611572.
Testo completoLi, M. S. F. "Investigating the effects of applying a high voltage DC electric field in a flame using a point to plane electrode arrangement". Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1433168/.
Testo completoNattrass, Gillian Lorraine. "A new route to the Annonaceous acetogenins : a total synthesis of 10-hydroxyasimicin". Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616253.
Testo completoCoggins, Adam J. "Studies toward a prebiotic protometabolism". Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/10038454/.
Testo completoBroughton, Howard Barff. "A total synthesis of showdomycin". Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37646.
Testo completoButtler, Thomas. "A total synthesis of (+/-)-sparteine". Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616083.
Testo completoFouche, Marianne. "Total synthesis of cruentaren A". Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/14610.
Testo completoBlack, Gregory Philip. "Synthetic studies towards guanidine alkaloids". Thesis, Bangor University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263304.
Testo completoTakle, A. K. "The synthesis of lacrimin A". Thesis, University of Southampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234027.
Testo completoPayne, Lloyd James. "Synthetic studies towards selected natural products". Thesis, University of Sussex, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388677.
Testo completoHuby, Nicholas John Silvester. "Synthetic studies of (±)-anatoxin-a related to its use in affinity chromatography". Thesis, University of Bath, 1989. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329541.
Testo completoBerthuel, Marie. "Microstructuration de surface et protection par encapsulation : applications aux biocapteurs". Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALV002.
Testo completoThis thesis explores two ways to enhance the performance of an electrochemical affinity biosensor for the detection of dengue anti-NS1 antibodies.The first goal was to improve the limit of detection and sensitivity of biosensors using microstructuration of the transducer. Based on finite element modelling, an optimal range of the microcone geometric parameters was defined. After construction, the microcone-covered electrodes were characterised using cyclic voltammetry and scanning electron microscopy. At the end of the optimisation process, glucose biosensors were fabricated to demonstrate the increased performance gains of an amperometric biosensing platform. Finally, in order to validate the interest of the microcones for an affinity biosensor, a label-free impedimetric immunosensor allowing the quantification of the cholera toxin B-subunit was studied as a model before performing an immunosensor of interest for dengue antibodies. The immunosensors were made on two types of electrodes: microcone-coated electrodes and interdigitated electrodes.A second goal was to improve the shelf-life of lateral-flow biosensors by microencapsulating labelled biomolecules, mandatory for competitive detection. For this purpose, low-cost polymer microcapsules have been developed. Methylene blue and an enzyme, glucose oxidase, were encapsulated in a dry state. Their release was followed by UV-visible spectroscopy and/or electrochemistry after breaking the microcapsules by mechanical action and/or with ultrasonic agitation
O'Hara, Fionn. "Sequential metal-catalyzed C-H bond functionalization as a strategy for natural product synthesis : development of a route to a fully functionalized dictyodendrin core". Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610162.
Testo completoMoreno, Guerra Adrian. "Cu(0) wire-mediated SET-LRP in biphasic systems and development of stimuli cleavable polymers". Doctoral thesis, Universitat Rovira i Virgili, 2019. http://hdl.handle.net/10803/670490.
Testo completoLa polimerización radicalaria catalizada por Cu(0) es una de las principales metodologías en el campo de las polimerizaciones radicalarias debido a su alto grado de simplicidad i la posibilidad de sintetizar polímeros con estructuras perfectamente definidas. En esta misma línea el desarrollo de sistemas poliméricos capaces de encapsular fármacos es una línea de investigación en constante desarrollo y de gran interés ya que la necesidad de mejorar la solubilidad de fármacos hidrofóbicos y liberarlos bajo la presencia de determinados estímulos de biológica relevancia sigue siendo una tarea complicada. El objetivo principal de esta tesis es investigar la polimerización radicalaria catalizada por Cu(0) en sistemas bifásicos con el objetivo de obtener polímeros con un alto grado de estructura definida. En última instancia la aplicación de este tipo de polimerización radicalaria junto con otros métodos de polimerización será empleado para el desarrollo de polímeros sensibles a ciertos estímulos de biológica relevancia con la finalidad encapsular fármacos y liberarlos de manera controlada.
Cu(0)wire-catalyzed SET-LRP has been postulated as one of the most versatile LRP techniques due to its operational simplicity which enables the construction of well-defined polymers and more complex architectures. In particular, the development of polymeric materials with suitable applications for medicine (e.g. polymeric nanoparticles able to encapsulate and release drugs) is a field of growing interest since they improve the poor solubility of hydrophobic drugs in aqueous media. However, their selective delivery under the application of different biological relevant stimuli still remains challenging. The main objective of this thesis is to investigate the Cu(0)wire-catalyzed SET-LRP in “programmed” biphasic systems and to explore the potential and limitations of this methodology with the ultimate goal of obtaining well-defined polymers with complex architectures and maximum end-group fidelity. Eventually, the application of biphasic SET-LRP and other polymerization techniques has been used for the synthesis of stimuli cleavage polymers and their potential application as drug delivery systems has been studied.
Kattirtzi, John Andrew. "A density functional theory study on a manganese dioxide-water interface : acidity constants and redox potentials". Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648581.
Testo completoHorsley, Helen Tracey. "A tandem route to histrionicotoxin 285A". Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614812.
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