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Mécanisme de prise et rhéologie de liants géopolymères modèles / Setting mechanism and rheology of model geopolymer bindersFavier, Aurélie 30 September 2013 (has links)
Il est communément admis que les géopolymères sont des solutions potentielles comme alternative aux liants hydrauliques classiques. Les géopolymères sont produits à partir de réactifs non carbonés contrairement au ciment portland et nécessitent relativement peu d'énergie pour être élaborés. Ce sont des liants inorganiques issus de l'activation alcaline d'aluminosilicates. Afin de faire des géopolymères une alternative viable et industriellement intéressante, plusieurs verrous technologiques doivent être levés en particulier sur leur mise en œuvre et les mécanismes chimiques impliqués au très jeune âge. Les études précédentes sur les mécanismes de cette réaction de géopolymérisation montrent l'existence d'un mécanisme en trois phases (dissolution – réorganisation – polymérisation). Notre étude s'est portée sur les mécanismes impliqués dans le comportement à l'état frais et en prise de géopolymère modèle à base de métakaolin. Pour cela, nous avons développé une approche combinée entre les mesures rhéologiques et chimiques (RMN liquide) afin de répondre à la complexité de l'hétérogénéité chimique locale pendant la géopolymérisation. Dans les deux premières parties de la thèse, nous nous sommes intéressés à comprendre le développement des propriétés mécaniques du gâchage à la prise du géopolymère. Lors de mesures de suivi de module élastique au cours du temps, nous observons également trois phases, une première augmentation de module dès les premières centaines de secondes, un plateau caractéristique d'une période de latence puis une seconde augmentation de module après plusieurs heures. Dans un premier temps, nous sommes intéressés à la première augmentation de module. Il a été établi que l'origine de ce module était la formation d'un premier gel de rapport Si/Al < à 4.5 localisé au niveau des joints de grains de métakaolin. Dans un second temps, nous sommes focalisé sur la dernière augmentation de module dont l'origine est la formation d'un second gel dont la composition chimique est celle du produit final c'est-à-dire le géopolymère de rapport Si/Al ~2.Finalement, dans une troisième partie, nous avons mis évidence les principales différences qui existent entre les géopolymères et de ciment Portland d'un point de vue rhéologique. Ces matériaux se comportent comme des fluides newtoniens. Les interactions entre les particules sont dominées par les effets hydrodynamiques, qui sont principalement contrôlés par la viscosité élevée de la solution alcaline de silicate et non par la contribution des contacts directs entre les grains de métakaolin / It is commonly accepted that the geopolymers are potential solutions as an alternative to conventional hydraulic binders. Geopolymers are produced from no-carbon reactants unlike Portland cement and require relatively little energy to be developed. These are inorganic binders from the alkali activation of aluminosilicates. To make a geopolymer as viable alternative and industrially interesting, several technological hurdles must be overcome in particular, their casting and the chemical mechanisms involved at very early age. Previous studies on the mechanisms of this reaction of geopolymerisation show the existence of a three phase's mechanism (dissolution - reorganization - polymerization). Our study focused on the mechanisms involved in fresh behavior and during setting of model metakaolin based geopolymers. For this, we have developed a combined approach between the rheological measurements and chemical measurements (liquid NMR) to respond to the complexity of the local chemical heterogeneity during geopolymerisation. In the first two parts of the thesis, we are interested in understanding the development of mechanical properties from mixing to setting of geopolymers. During the measurement of the elastic modulus' evolution, we also observe three phases, the first increase of elastic modulus during the first few hundred seconds, a plateau characteristic of a latency period followed by a second increase of elastic modulus after several hours. As a first step, we are interested in the first increase of modulus. It was established that the origin of this modulus was the formation of a first gel with a Si / Al ratio <4.5 localized at the grain boundaries of metakaolin. In a second step, we focused on the last increase of the elastic modulus. The origin is the formation of a second gel; the chemical composition is that of the final product that is to say the geopolymer with a Si / Al ratio ~ 2.Finally, in the third part, we have identified the major differences between geopolymer and Portland cement from a rheological point of view. These materials behave as Newtonian fluids. The interactions between the particles are dominated by hydrodynamic effects, which are mainly controlled by the high viscosity of the alkaline silicate solution and not the contribution of direct contacts between the grains of metakaolin
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Identificação de adesinas bacterianas por phage display. / Identification of bacterial adhesins through phage display.Ana Tung Ching Ching 03 December 2012 (has links)
A leptospirose é uma zoonose de importância mundial causada por bactérias do gênero Leptospira. No Brasil, a maioria dos casos é causada por L. interrogans sorovar Copenhageni. O objetivo destre trabalho foi identificar adesinas de leptospira pela técnica de Phage display. Bibliotecas com fragmentos genômicos resultaram na idendificação de ligantes de leptospira com afinidade por tecidos de hamster. Uma varredura dessas bibliotecas contra heparan sulfato proteoglicano (HSPG) identificou como ligantes as proteínas LigA e LigB. Proteínas recombinantes foram produzidas e submetidas à ligação às células de mamíferos e aos componentes de matriz extracelular. LigB recombinante foi capaz de se ligar ao HSPG, à heparina e às células de mamíferos. HSPG e heparina foram capazes de reduzir significativamente a interação dessa proteína com as células. Estes resultados evidenciam o papel de proteínas da leptospira na sua interação com o hospedeiro e ilustram a possibilidade do uso da técnica de phage display para identificar possíveis adesinas. / Leptospirosis is a worldwide important zoonosis caused by bacteria of the genus Leptospira. In Brazil, most cases is caused by L. interrogans serovar Copenhageni. Our goal was to identify leptospiras adhesins by phage display technique. Libraries of genomic fragments resulted in the identification of ligands with affinity for leptospiras hamster tissues. Screening these libraries against heparan sulfate proteoglycan (HSPG) identified the proteins LigA and LigB. Recombinant proteins were produced and subjected to binding to mammalian cells and extracellular matrix components. LigB recombinant was able to bind to HSPG, heparin and mammalian cells. HSPG and heparin were able to significantly reduce the interaction of this protein with cells. These results highlight the role of leptospiras proteins in its interaction with the host and illustrate the possibility of the use of phage display technique to identify potential adhesins.
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Pojivové systémy na bázi aluminasilikátů / Binder systems on the base aluminasilicateTůmová, Veronika January 2008 (has links)
This thesis describes influence of plasticizers and setting accelerators in binder system based aluminasilikates. Following survey includes changes of characteristics of aluminate cements in combination with various setting accelerators. Practical testing and measuring summarizes and compares interdependence of structure, compressive strength, permeability and abrasion resistance. As a final part of thesis individual mixes are analysed economically and are accompanied by suggestions for future use and use in working experience.
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Traitement et valorisation de sédiments de dragage phosphatés en technique routière / Treatment and valorization of treated dredged sediments in civil engineeringDia, Moussa 28 May 2013 (has links)
Le dragage des sédiments est nécessaire afin de maintenir le transport et les activités maritimes mais les sédiments extraits sont souvent pollués en métaux lourds et en composés organiques. Face à la nécessité du dragage et à la pollution, la société Solvay a mis au point un procédé permettant de traiter les sédiments dragués pour envisager une valorisation : le procédé Novosol®. Ce procédé a pour but de stabiliser les métaux présents dans les sédiments par phosphatation (ajout d’acide phosphorique H3PO4) et de dégrader la matière organique par calcination à 650°C. Un acide phosphorique pur est habituellement utilisé pour l’étape de phosphatation. Cependant, dans la présente étude plusieurs acides phosphoriques de nature et de sources différentes fournis par la société PRAYON ont été utilisés. Les principales caractéristiques de deux sédiments traités avec plusieurs types d’acides phosphoriques sont présentées dans cette thèse. D’un point de vu mécanique les formulations effectuées avec les sédiments traités sont conformes aux normes routières. L’étude environnementale a montré que les quantités de métaux lourds relarguées par les matériaux formulés à partir des sédiments traités sont inférieures aux seuils fixés par la législation en vigueur. Les résultats obtenus avec les différents types d’acides sont similaires. Cela permet d’envisager l’utilisation des sédiments de dragage traité Novosol® en technique routière. / Dredging of sediments is necessary in order to maintain maritime activities and for flood prevention. However increased industrial activities are causing accumulation of pollutants in the sediments. The main contaminants are heavy metals and organic compounds. Because of the cost of storage, treatment and valorization can be economically sound. This study focuses on the technology to treat heavy metals from dredged sediments using phosphoric acid (H3PO4) (the Novosol®process developed by Solvay company) with a goal to stabilize heavy metals by capturing them in a calcium phosphate matrix and to destroy organic matter by calcination at 650°C. Several studies have been conducted in this field. The stabilized materials obtained have been used in civil engineering. However these studies have never assessed the effect of the composition of the phosphoric acid on the treatment. In this thesis dissertations the effect of two types of phosphoric acids with various purities and origins provide by PRAYON company were compared. The investigation focuses on the effect of the phosphoric acids on the environmental behavior of metals and on the geotechnical properties of the dredged sediment. The environmental study has shown that the concentration of heavy metals released by materials made from treated sediments are below the regulation limits . The results obtained with the different types of acids are comparable. This allows to consider the use of treated dredged sediment by process Novosol® as road materials.
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Selection of affibody and domain antibody binders to the Binding Region (BR) domain of theadhesion protein PsrP of Streptococcus pneumoniae / Selektion av affibodies och domän-antikroppar mot Binding Region (BR)-domänen avadhesionsproteinet PsrP hos Streptococcus pneumoniaeHjelm, Linnea January 2017 (has links)
No description available.
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Dispersed bio-based binders as drop-in solution for non-woven industry / Biobaserade dispersersionsbindemedel som alternativ till nonwovenindustrinIngo, Emma January 2021 (has links)
Sammanfattning på svenska: Målet med projektet var att utveckla ett system av disperserade bindemedel för non-wovenindustrin som inte förutsätter omfattande förändringar i befintliga processer. Bindemedlet ska vara biobaserat, bionedbrytbart och endast bestå av byggstenar som är matkontaktsgodkända av FDA och BFR. Ett disperserat system möjliggör en hög torrhalt tillsammans med en låg viskositet som i kombination med stor anpassningsbarhet kan konkurrera med fossila bindemedel på marknaden. Denna studie behandlar användande och modifiering av vattenlösliga biopolymerer för utveckling av ett disperserat system med förmågan att binda samman fibrer i ett non-wovenmaterial. Flertal analytiska metoder och observationer används, som Fourier transform infraröd spektroskopi (FTIR), laddningsdensitet, viskositet och optisk mikroskopi, för att mäta framgången av konceptet. Olika modifieringar och ympningsstrategier användes under projektet och deras inverkan på biopolymerer diskuteras. / The aim of the project was to develop a dispersed binder as a drop-in solution for non-woven industry. The binder should be bio-based, biodegradable and consist only of FDA and BFR food contact approved components. A dispersed system enables the binder to have a high solid content while having a low viscosity. This feature, in combination with a binder with tunable properties, can be a competitive alternative for the fossil-based binders in the market. This study focuses on the use and modification of biopolymers with binding capacity to form a dispersed system from water-soluble biopolymers. The success of the reaction was evaluated by using a multitude of analytical methods and observation, such as Fourier transform infrared spectroscopy (FTIR), charge distribution and viscosity measurements. Several modification strategies and grafting agents were used and their impact on the biopolymer is discussed.
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Development of a standard test method for determining the Bitumen bond strength of emulsions : a South African perspectiveGreyling, Andries Hendrik 12 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Chip and spray surfacing seals has been widely used in South Africa as the preferred surface treatment for rural roads. The design of these seals has also experienced renewed interest and continuous development in several other countries over the past two decades. In South Africa seals are continually used as increasing attention is given to the periodic maintenance of existing surfaced roads. There is also a significant increase in the use of surfacing seals in North America as the need to develop more energy and resource efficient surfacing options becomes a priority.
Despite this growing use of surface seals, the seal design and especially the selection of binder type and grade does not always follow scientific processes. Seals are often designed based on client preference, previous experience, material availability and industry trends. With an ageing road network and limited funding to ensure timeous maintenance, the focus in South Africa is moving towards more stringent and scientific design processes.
The USA and Europe, forced by increasing traffic volumes and heightened performance demands, are moving towards performance- based specification to account for deficiencies in their current surface seal design methods. One of the major failure mechanisms of surface seals is ravelling which takes place when the binder and the aggregate bond becomes weak and are broken by the forces generated by traffic. This leads to loose aggregate on the road which in turns leads to bare surface patches and broken windscreens. To prevent and address this as part of the development of performance-based specifications, the need for a simple and inexpensive technique for evaluating bitumen and bitumen emulsion bond strength development over time, as well as binder-aggregate compatibility, was identified.
Although various tests exist for investigating adhesion between bituminous emulsions and aggregate chips most of the tests does not deliver the level of information required by the performance-based specifications. The Bitumen Bond Strength (BBS) test method was therefore developed with the aim to address some of the limitations encountered in evaluating bond strength between binders and aggregates.
The BBS test (AASHTO TP-91, 2011) was developed by the University of Wisconsin – Madison (UWM) in partnership with the University of Ancona – Italy (UAI) and the University of Stellenbosch – South Africa (US) specifically for evaluating bond strength between aggregates and hot applied binders and emulsions, respectively.
US became involved in BBS test efforts in 2008 to assist in the development and practical evaluation of the BBS test method. UAI contributed significantly to the development of the test apparatus through their work in conjunction with UWM. Due to time and resources available, the involvement of the US was limited to various discussion sessions, a study tour, the evaluation of the BBS test, and conducting a series of control tests.
By using the Bitumen Bond Strength test it was possible to evaluate the practicality and repeatability of the developed procedure and the results measured was successfully used to evaluate the bond strength development of modified and unmodified bitumen emulsions on tillite and granite aggregates. It was also possible to correlate the results achieved at the University of Stellenbosch with results from the University of Wisconsin-Madison due to the fact that testing took place at both institutions.
The development of the test and the inter-laboratory test results in essence reinforced the hypothesis that the BBS test protocol can be used to effectively evaluate bond strength of different emulsion types and aggregate types. Except for the loading rate which is a known critical influence, the emulsion type and curing intervals are both identified as the most significant other factors contributing to bond strength development.
Aggregate type is also identified as a significant factor that will influence the bond strength development. Interactions between emulsion type and curing interval are identified as the most significant interaction. A lot of further validation test on the BBS test method is still required for the test to be integrated into a performance-based specification system for surface seals. / AFRIKAANSE OPSOMMING: “Chip and Spray” oppervlak seëls is die verkose seël tipe vir gebruik op Suid Afrikaanse plattelandse paaie. Die ontwerp van hierdie tipe seëls is ook tans besig om hernude aandag te trek in heelwat lande. In Suid Afrika word die tipe seël al meer gebruik soos die behoefte na herseël projeke op die verouderde pad netwerk groei . Daar is ook heelwat groei in die gebruik van “Chip en Spray” seëls in Noord Amerika aangesien daar n behoefte is om n meer energie en materiaal effektiewe seëls te gebruik.
Ten spyte van die groeiende gebruik van hierdie seëls het daar min wetenskaplike ontwikkeling plaasgevind in the ontwerp daarvan. Seëls word meestal ontwerp gebaseer op klient voorkeur , ondervinding, materiaal beskikbaarheid en ook industrie norms. ‘n Verouderde pad netwerk dwing die Suid Afrikaanse industrie om meer deeglike en wetenskaplike ontwerp prosedures te volg.
Die VSA en Europa word deur vinnig groeiende verkeersvolumes en verhoogte kwaliteits behoeftes gedwing om prestasie gebaseerde spesifikasies te ontwikkel. Een van die hoof defekte op seëls is klipverlies wat plaasvind as die verbinding tussen die bitumen en aggregaat verswak en gebreek word deur die kragte wat deur verkeer oorgedra word. Dit lei tot los klip op die pad wat weer tot skade aan voertuie lei. Om dit te voorkom en aan te spreek het die behoefte laat ontwikkel vir n maklike en goedkoop tegniek om te meet hoe sterk die verbinding is wat ontwikkel tussen verskillende bitumen, bitumen emulsies en aggregaat monsters.
Alhoewel daar alreeds toetse bestaan wat kan toets hoe sterk die verbinding is , gee die meeste van die toetse nie die informasie wat benodig word deur die voorgestelde prestasie gedrewe spesfikasies nie. Die “Bitumen Bond Strength” (BBS) toets metode is daarom ontwikkel om die tekortkoming in die toets van die bitumen en aggregaat verdindinge aan te spreek.
Die BBS toets (AASHTO TP-91, 2011) is ontwikkel by die Universiteit van Wisconsin – Madison (UWM) in vennootskap met die Universiteit van Ancona – Italy (UAI) en die Universiteit van Stellenbosch (US) , spesifiek om die die sterkte van die verbinding wat vorm tussen aggregaat en bitumen te meet.
Die US het in 2008 betrokke geraak by die BBS toets studie om hulp te verleen met die ontwikkeling en praktiese evalueering van die BBS toets metode. As gevolg van tyd en personeel tekorte is die betrokkendheid by die US beperk tot verskeie besprekings sessies, n studie toer, die evalueering van die BBS toets sowel as die voltooing van n uitgebreide stel toetse.
Deur die voltooing van eksperimente met die BBS toets was dit moontlik om die uitvoerbaarheid en herhaalbaarheid van die ontwikkelde prosedure te toets. Die resultate van die toetse is suksesvol gebruik om die ontwikkeling van die verbinding sterkte tussen gemodifiseerde en ongemodifiseerde bitumen emulsies en tilliet en graniet te definïeer en te evalueer. Dit was ook moontlik om die resultate van die Universiteit Stellenbosch en die Universiteit of Wisconsin-Madison suksesvol met mekaar te vergelyk aangesien toetse by beide die instansies voltooi is.
Die ontwikkeling van die toets en die inter laboratorium toets resultate het dit moontlik gemaak om die hipotese te bevestig dat die BBS toets prosedure effektief gebruik kan word om die bitumen en aggregaat verdindinge te toets en te evalueer. Behalwe vir die tempo van die lading waarteen die aftrek sterkte getoets word , is die emulsie tipe en die nabehandeling tydperk beide geidentifiseer as die mees beduidende invloede wat bydrae tot die ontwikkeling van die verbinding sterkte.
Die aggregaat tipe is ook geidentifiseer as n belangrike faktor wat die verbinding sterkte ontwikkeling sal beïnvloed. Die interaksie tussen die emulsie tipe en nabehandeling tydperk was geïdentifiseer as die mees beduidende interaksie. Daar sal wel nog heelwat eksperimente voltooi moet word met die BBS toets prosedure voordat dit volkome geïntegreer kan word as deel van n prestasie gebaseerde spesifikasie stelsel vir die ontwerp van seëls.
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Une nouvelle stratégie de traitement de la maladie cœliaque basée sur les polymères séquestrantsPinier, Maud 11 1900 (has links)
La maladie cœliaque ou sprue cœliaque est une intolérance au gluten. Il s’agit d’une maladie inflammatoire de l’intestin liée à l’ingestion de gluten chez des personnes génétiquement susceptibles. Ce désordre présente une forte prévalence puisqu’il touche 1 % de la population mondiale. En l’état actuel des choses, il n’existe aucun outil pharmacologique pour traiter ou pallier à cette maladie. Cependant, grâce aux avancées dans la compréhension de sa pathogenèse, de nouvelles cibles thérapeutiques ont été identifiées. À l’heure actuelle, le seul traitement efficace consiste à suspendre la consommation de l’agent pathogène, à savoir le gluten. Le gluten est un ensemble de protéines de stockage des céréales contenu dans le blé, l’orge et le seigle. Le gluten du blé se subdivise en gluténines et gliadines. Ce sont ces dernières qui semblent les plus impliquées dans la maladie cœliaque. Les gliadines et ses protéines apparentées (i.e. sécalines et hordéines, respectivement dans le seigle et l’orge) sont riches en prolines et en glutamines, les rendant résistantes à la dégradation par les enzymes digestives et celles de la bordure en brosse. Les peptides résultant de cette digestion incomplète peuvent induire des réponses immunitaires acquises et innées.
L’objectif principal de cette thèse était de tester un nouveau traitement d’appoint de la maladie cœliaque utile lors de voyages ou d’évènements ponctuels. Dans les années 80, une observation italienne montra l’inhibition de certains effets induits par des gliadines digérées sur des cultures cellulaires grâce à la co-incubation en présence de mannane: un polyoside naturel composé de mannoses. Malheureusement, ce traitement n’était pas applicable in vivo à cause de la dégradation par les enzymes du tractus gastro-intestinales du polymère, de par sa nature osidique. Les polymères de synthèse, grâce à la diversité et au contrôle de leurs propriétés physico-chimiques, se révèlent être une alternative attrayante à ce polymère naturel. L’objectif de cette recherche était d’obtenir un polymère liant la gliadine, capable d’interférer dans la genèse de la maladie au niveau du tube digestif, afin d’abolir les effets délétères induits par la protéine.
Tout d’abord, des copolymères de type poly (hydroxyéthylméthacrylate)-co-(styrène sulfonate) (P(HEMA-co-SS)) ont été synthétisés par polymérisation radicalaire contrôlée par transfert d’atome (ATRP). Une petite bibliothèque de polymères a été préparée en faisant varier la masse molaire, ainsi que les proportions de chacun des monomères. Ces polymères ont ensuite été testés quant à leur capacité de complexer la gliadine aux pH stomacal et intestinal et les meilleurs candidats ont été retenus pour des essais cellulaires. Les travaux ont permis de montrer que le copolymère P(HEMA-co-SS) (45:55 mol%, 40 kDa) permettait une séquestration sélective de la gliadine et qu’il abolissait les effets induits par la gliadine sur différents types cellulaires. De plus, ce composé interférait avec la digestion de la gliadine, suggérant une diminution de peptides immunogènes impliqués dans la maladie. Ce candidat a été testé in vivo, sur un modèle murin sensible au gluten, quant à son efficacité vis-à-vis de la gliadine pure et d’un mélange contenant du gluten avec d’autres composants alimentaires. Le P(HEMA-co-SS) a permis de diminuer les effets sur les paramètres de perméabilité et d’inflammation, ainsi que de moduler la réponse immunitaire engendrée par l’administration de gliadine et celle du gluten. Des études de toxicité et de biodistribution en administration aigüe et chronique ont été réalisées afin de démontrer que ce dernier était bien toléré et peu absorbé suite à son administration par la voie orale. Enfin des études sur des échantillons de tissus de patients souffrants de maladie cœliaque ont montré un bénéfice therapeutique du polymère.
L’ensemble des travaux présentés dans cette thèse a permis de mettre en évidence le potentiel thérapeutique du P(HEMA-co-SS) pour prévenir les désordres reliés à l’ingestion de gluten, indiquant que ce type de polymère pourrait être exploité dans un avenir proche. / Celiac Disease or celiac sprue is identified as a gluten intolerance. It is an inflammatory disorder of the intestine triggered by the ingestion of gluten in genetically susceptible individuals. This condition is highly prevalent because it affects up to 1% of the worldwide population. Nowadays, there is no pharmacological treatment available to treat or off set to the disease. Due to the huge progress in the understanding of the pathogenesis, new therapeutic targets have been discovered. At the present time, the only effective treatment remains the strict lifelong abandonment of the pathogen agent, gluten. Gluten encompasses the storage proteins in wheat, rye and barley. The wheat gluten is divided into glutenins and gliadins. The latter seem to be the most important trigger in the celiac disease. Gliadins and the related proteins (i.e. secalins and hordeins, respectively in rye and barley) are rich in prolin and glutamin residues, conferring them to be resistant by enzymatic digestion. The resulting peptides of the incomplete process may set off the inflammatory reaction.
The main objective of this thesis was to test a new supportive therapy in treating celiac disease, useful in punctual occasion (i.e. during travel or social event when the gluten-free property cannot be ascertained).
In the 1980’s, inhibition of some gliadin-induced effects on cell cultures were observed owing to mannan co-incubation. However, this compound, due to his osidic nature, may be cleaved by digestive enzymes in vivo. Synthetic polymers prove to be an attracting alternative owing to the tunability of their physical and chemical properties. The goal of this study was to obtain a polymeric gliadin-binder, interferring with the pathogenesis of the celiac disease in the gastro-intestinal tract, to abrogate the gliadin induced effects.
Atom transfer radical polymerization was used to synthesize copolymers of the type poly (hydroxyethylméthacrylate)-co-(styren sulfonate) (P(HEMA-co-SS)). A small library of polymers varying in their molecular weight and in their constituting monomers ratio was prepared. The ability of these polymers to sequester gliadin was assessed at stomacal and intestinal pH. The best candidates were further evaluated in cell cultures. Our results revealed that a selective binding was obtained with the P(HEMA-co-SS) (45:55 mol%, 40 kDa). This compound abolished gliadin-induced effects on various cell lines. In addition, gliadin digestion was hindered, suggesting a decrease in the formation of immunogenic peptides known to trigger the diseases. In vivo experiments were additionally carried out on a murine model of gluten-sensitivity with this polymeric candidate. Its efficacy towards pure gliadin and gluten containing food was tested. P(HEMA-co-SS decreased gliadin–induced effect on permeability and inflammatory parameters and modulated the immune response due to gliadin/gluten gavage. Toxicity and biodistribution studies following acute and chronic administration were performed on murine to demonstrate that the polymer was well tolerated and not absorbed after oral administration. Finally, biopsies of patients suffering from CD disease exhibited therapeutic benefit of the polymer.
Altogether, the results presented in this thesis evidenced the potential of P(HEMA-co-SS) to prevent the gluten-induced disorder, indicating that this type of polymer may be useful in a near future.
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A Compiler for the dependently typed language BelugaFerreira Ruiz, Francisco 05 1900 (has links)
Les structures avec des lieurs sont très communes en informatique. Les langages de programmation et les systèmes logiques sont des exemples de structures avec des lieurs. La manipulation de lieurs est délicate, de sorte que l’écriture de programmes qui ma- nipulent ces structures tirerait profit d’un soutien spécifique pour les lieurs. L’environ- nement de programmation Beluga est un exemple d’un tel système. Nous développons et présentons ici un compilateur pour ce système. Parmi les programmes pour lesquels Beluga est spécialement bien adapté, plusieurs peuvent bénéficier d’un compilateur. Par exemple, les programmes pour valider les types (les "type-checkers"), les compilateurs et les interpréteurs tirent profit du soutien spécifique des lieurs et des types dépendants présents dans le langage. Ils nécessitent tous également une exécution efficace, que l’on propose d’obtenir par le biais d’un compilateur. Le but de ce travail est de présenter un nouveau compilateur pour Beluga, qui emploie une représentation interne polyvalente et permet de partager du code entre plusieurs back-ends. Une contribution notable est la compilation du filtrage de Beluga, qui est particulièrement puissante dans ce langage. / In computer science, structures with variable binders are very common. Program- ming languages and logical frameworks are examples of structures with binders. Thus writing programs that deal with these kinds of data benefits with explicit support for data binding. The Beluga programming environment is an example of such a system.
In this work we develop and present a compiler for the system. Many of the programs that Beluga is specially well suited for writing can benefit from a compiler. For example, some of the kinds programs that would benefit more are type-checkers, compilers and interpreters that take advantage of the binder support and dependent types present in the language, and also require a reasonably fast run-time.
Our goal in this work, is to present a compiler for the Beluga system, that uses a very versatile internal representation that helps with the development of the system, and allows a sharing of code between several back-ends. Furthermore, we present a way of compiling the uniquely powerful pattern language supported by Beluga.
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Efeito da adição de ácidos fosfóricos no comportamento reológico de ligantes asfálticos puros e modificados com copolímero SBS / Effect of phosphoric acid in the rheological behavior of pure and modified asphalt binders with SBS copolymerSobreiro, Fernanda Pilati 27 March 2014 (has links)
A adição de modificadores no ligante asfáltico visando melhorar o seu comportamento é uma prática comum atualmente. Existem vários tipos de modificadores, entre eles o mais utilizado nas rodovias federais brasileiras é o copolímero SBS. Além dos polímeros, o ácido polifosfórico (PPA) é outro tipo de modificador que produz boas características quando adicionado ao ligante asfáltico. Apesar do efeito positivo, sabe-se que este material é importado, o que dificulta sua aquisição e pode tornar o produto final muito caro. Tendo em vista a possibilidade de se trabalhar com um produto de mesma base, mas de origem nacional, o que o tornaria o modificador mais acessível, optou-se por verificar o comportamento da adição de ácido fosfórico (PA85) ao ligante asfáltico. Sendo assim, o propósito desta tese é analisar o efeito da adição de ácidos fosfóricos no comportamento reológico de ligantes asfálticos puros e modificados com o copolímero SBS. Para tanto, realizou-se ensaios empíricos e reológicos com o intuito de verificar o comportamento destes materiais. Na primeira parte da pesquisa, dois ligantes asfálticos de base, CAP50/70 de classificação PG64-XX, (Replan e Lubnor), foram modificados somente com a adição dos dois ácidos (PPA e PA85), enquanto na segunda parte esses ligantes asfálticos de base foram modificados com o copolímero SBS com ou sem a presença dos ácidos. Os ensaios avaliados foram penetração, ponto de amolecimento, viscosidade rotacional, ensaio de fluência e recuperação sob tensão múltipla (MSCR), LAS modificado, e estabilidade à estocagem. De maneira geral, a adição dos modificadores melhora o comportamento dos ligantes asfálticos, tendo em vista que melhoram a recuperação, ficam menos sensíveis à deformação permanente e são mais tolerantes à fadiga. Pode-se constatar que o tipo de ligante asfáltico de base influencia diretamente o comportamento dos materiais, independente dos modificadores adicionados. A adição dos modificadores foi mais expressiva no ligante asfáltico proveniente da Replan. Em relação aos ácidos, conclui-se que a adição do PA85 foi satisfatória, uma vez que apresentou comportamento semelhante ao do ácido PPA, porém com efeito um pouco menos expressivo. A adição dos ácidos melhorou a estabilidade à es tocagem dos ligantes asfálticos modificados, e pode-se constatar que a adição de um destes modificadores permite a redução do teor do copolímero SBS. Quanto à capacidade de suporte de tráfego, a adição de altos teores desses modificadores não é viável, devido ao fato de apresentarem suporte similar a ligantes asfálticos modificados com teores baixos e intermediários. / The addition of modifiers in asphalt binder to improve its behavior is a common practice nowadays. There are many types of modifiers, among them the most used in the Brazilian federal highways is the SBS copolymer. In addition to polymers, polyphosphoric acid (PPA) is another type of modifier that produces good characteristics when added to asphalt binder. Despite the positive effects, it is known that this material is imported, which makes its purchase as well as the final product very expensive. Considering the opportunity to work with a product with the same basic component, but of national origin, which would make it the most affordable modifier, the present study decided to verify the behavior of the addition of phosphoric acid (PA85) to the asphalt binder. Therefore, the purpose of this thesis is to analyze the effect of the addition of phosphoric acid to the rheological behavior of pure and modified asphalt binders with the SBS copolymer. For both, empirical and rheological tests were conducted in order to verify the behavior of these materials/substances. In the first part of the research, two asphalt binders base CAP50/70 asphalt binder graded PG64-XX (Replan and Lubnor) were modified only with the addition of the two acids (PPA and PA85), while in the second part of these asphalt binders base were modified with SBS copolymer with or without the presence of acids. The tests evaluated penetration, softening point, rotational viscosity, multiple stress creep and recovery (MSCR), LAS modified, and storage stability. In general, the addition of the modifiers enhances the behavior of the asphalt binders, for they improve recovery, are less susceptible to rutting and are more resistant to fatigue. It was found that the type of asphalt binder base directly influences the behavior of materials, regardless of added modifiers. The addition of modifiers was greater in the asphalt binder from the Replan. Compared to acids, it is concluded that the addition of PA85 was satisfactory, since the performance was similar to the PPA acid behavior, but with slightly less significant effect. The addition of acid improved the storage stability of the modified asphalt binders, and it was found that the addition of such modifiers allows reducing the content of the SBS copolymer. Regarding the ability to support traffic, the addition of high levels of these modifiers is not feasible because they show similar support for modified asphalt binders with low and intermediate levels.
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