Les Bétons de Poudre Réactive (BPR) sont connus pour leur résistance très élevée et leur bonne durabilité, mais aussi pour leur prix élevé. L’objectif de cette étude concerne la mise au point d’une formulation de BPR extrudable (BPR). Des essais préliminaires d’écoulement au mini cône d’Abrams ont été réalisés avec des teneurs variées en superplastifiant et en substituant partiellement la fumée de silice par du quartz broyé. Cinq mélanges ont été retenus et caractérisés de façon systématique au microscope électronique à balayage et en diffraction des Rayons X. Une étude complète de retrait au jeune âge, de résistance mécanique et de durabilité face à l’azote et aux ions chlorure a été menée. Un montage expérimental d’extrusion a été mis au point. Un mélange incorporant du quartz broyé en remplacement d’une fraction de la fumée de silice et une composition optimisée en superplastifiant montre des propriétés intéressantes : extrudabilité, très bonne durabilité, performances mécaniques améliorées et retrait diminué. Sur cette composition, l’étude microstructurale met en évidence le rôle que joue le superplastifiant sur la chimie d’hydratation avec une forte consommation en bélite. Ce mélange permet ainsi de diminuer le coût de fabrication pour un BPR en permettant d’économiser la fumée de silice coûteuse et en ne nécessitant aucun traitement thermique. / Reactive Powder Concrete (RPC) is well known for ultra-high mechanical performances and very good durability as well as for a high cost. The aim of this study is to find an extrudable RPC. Abrams cone preliminary tests were made with various contents of superplasticizer and a partial substitution of silica fume by crushed quartz. Then, fives concrete samples were chosen and systematically characterized by scanning electron microscopy and X-ray diffraction. Then, a complete study was made including early-age shrinkage, mechanical strength, gas permeability and chloride diffusion measurements. An experimental extruder was build. Among the five compositions, one of them, where crushed quartz replaces a part of silica fume, exhibits very good properties: good extrudability, very good durability, and better mechanical strength with an improvement of shrinkage. The microstructural study of this composition highlights the effect of the superplasticizer on hydration, with high belite consumption. This composition allows a lower cost of RPC with a decreasing of silica fume content, without thermal treatment.

Orientador: Priscylla Tatiana Chalfun Guimarães Okamoto / Resumo: A doença renal crônica (DRC) é uma enfermidade comum em cães idosos. No insucesso do tratamento clínico tem-se a opção das terapias de substituição renal, onde se destaca a hemodiálise intermitente (HDI). Tanto a técnica de HDI como o estado clínico dos cães com DRC podem desencadear uma reação inflamatória. A proteína C reativa (CRP) é uma proteína de fase aguda que pode ser utilizada como marcador da resposta inflamatória em cães. O objetivo deste estudo foi de avaliar o uso da proteína C reativa como um biomarcador de lesão inflamatória na monitoração da resposta inflamatória de cães com DRC no estádio IV submetidos a hemodiálise intermitente e comparar dois métodos de dosagem da proteína C reativa em cães com doença renal crônica IV. Foram selecionados 16 cães com doença renal crônica IV, divididos em dois grupos: 8 animais no grupo tratamento clínico, 8 animais no grupo hemodiálise intermitente e 7 animais sadios no grupo controle. Foram coletadas amostras de sangue antes da primeira e da última sessão de tratamento de ambos os grupos, para avaliação de hemograma, bioquímica sérica (ureia, creatinina, albumina, potássio, fósforo). Para determinação das concentrações da proteína C reativa foi utilizado o método de ELISA (Dog CRP ELISA (CRP-4), Life Diagnostics Inc.) método de ELISA sanduíche (Kit CATALYST CRP TEST , IDEXX Catalyst®), ambos conforme as recomendações do fabricante. Foi observado elevada concentração de proteína C reativa no GHDI quando comparado com GC (p= ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Chronic Kidney Disease (CKD) is a common disease in older dogs. When the clinical treatment is unsuccessful, kidney replacement therapies become an option, the most prevalent of which is Intermittent Hemodialysis (IHD). Both the IDH technique and the clinical condition of the CKD patients may trigger an inflammatory reaction. C-reactive protein (CRP) is an acute phase protein that may be used as a marker for inflammatory response in dogs. This study aims at evaluating the use of C-Reactive Protein as a biomarker for inflammatory injuries in the monitoring process of the inflammatory response in dogs affected by Stage IV Chronic Kidney Disease undergoing intermittent hemodialysis, in addition to comparing the two different tests to measure CRP in these patients. Sixteen dogs with Stage IV chronic kidney disease were selected for the study and divided into two groups: 8 animals in the clinical treatment group; and 8 animals in the intermittent hemodialysis group. In addition, seven healthy animals were included in a third group as a control. Blood samples were collected before the first and the last treatment session for both groups for a full blood count and serum biochemistry assay (urea, creatinine, albumin, potassium and phosphorus). A canine CRP ELISA Kit (Dog CRP ELISA (CRP-4), Life Diagnostics Inc.) and the CATALYST CRP TEST device (IDEXX Catalyst®) were used to determine the concentration of C-Reactive protein according to the manufacturer’s instructions. We observed an... (Complete abstract click electronic access below) / Mestre

Astrocytes display a complex, stellate morphology in the brain, commensurate with their role in regulating nearly every functional aspect of the central nervous system. Innate activation of astrocytes is a classic hallmark of neurologic injury and disorder, characterized by proliferation, process hypertrophy, and transition toward polygonal morphology. However, the extent and consistency of these morphological changes, especially in the context of distinct pathologies, remain largely unknown. Here, changes in the fine neuroanatomy of astrocytes in rhesus macaque monkeys were characterized under a variety of conditions with relevance to translational research, including autistic-like behavior, bacterial and viral infections. Brain slices from paraffin embedded tissue archives were stained for glial fibrillary acidic protein, a reactive astrocyte marker, and imaged for both grey and white matter astrocytes. These cells were 3D-reconstructed in Neurolucida software and morphometric data including soma size, process length, volume and branching were analyzed and aggregated by animal and condition. It was found that process complexity in white matter astrocytes atrophied during lentiviral infection and depressive behavior, with decreased arbor length and tip quantity observed in SIV-infected and self-injuring animals. However, the opposite was seen during a bacterial infection, with increased arbor complexity and process length seen in Brucella-infected animals. Additionally, astrocytes from animals receiving oral naltrexone treatment for self-injurious behavior displayed a reversion from atrophied cell phenotypes back to original, control morphology. Thus, astrocyte activation and subsequent remodeling is not consistent, but rather context-dependent on the specific pathology and cellular subtype, and may be a driving factor in neurocognitive disorder. / acase@tulane.edu

Vaskuläre Komplikationen wie Atherosklerose sind bei Diabetikern weit verbreitet. Eine erhöhte Produktion reaktiver Sauerstoffspezies trägt zu einer Dysfunktion des Endothels bei Diabetes und hohen Glukosespiegeln bei. Glutathion (GSH) ist das häufigste zelluläre Thiol und stellt ein bedeutendens Antioxidans des menschlichen Organismus dar. Das Multidrug Resistance Protein 1 (MRP 1) ist im Endothel der Haupttransporter von oxidiertem GSH. Blockiert man MRP 1, so wird unter oxidativem Stress der intrazelluläre GSH-Spiegel erhalten. In dieser Arbeit wird der Einfluss von MRP 1 auf die endotheliale Funktion und Produktion reaktiver Sauerstoffspezies bei Diabetes und erhöhten Glukosespiegeln anhand von MRP 1-/- -Mäusen und Wildtyp-FVB-Tieren untersucht. Acht Wochen nach Injektion von STZ wurde die endothelabhängige Vasorelaxation an den isolierten thorakalen Aorten bestimmt. Diabetische Wildtyp-Tiere wiesen eine signifikant verminderte endothelabhängige Vasorelaxation auf. In MRP 1-/- -Tieren hingegen kam es zu keiner Beeinträchtigung der Endothelfunktion. Die endothelunabhängige Vasorelaxation war nicht signifikant unterschiedlich. STZ-induzierter Diabetes führte zu einer signifikant erhöhten Produktion von Superoxidanionen sowie Wasserstoffperoxid in Wildtyp-Tieren. Diabetische MRP 1-/- -Mäuse hingegen zeigten keinen Anstieg der Produktion reaktiver Sauerstoffspezies. Erhöhte Glukosekonzentrationen führten in vitro in humanen aortalen Endothelzellen ebenso zur erhöhten Superoxidanion-Produktion. In Zellen, in denen MRP 1 mittels siRNA herunterreguliert war, zeigte sich keine Erhöhung von Superoxidanionen. In Wildtyp-Mäusen führte Diabetes zu einer Verminderung des vaskulären GSH-Spiegels, wohingegen bei MRP 1-/- -Tieren keine Veränderung auftrat. Diese Daten weisen auf die wichtige Rolle von MRP 1 bei der unter hohen Glukosekonzentrationen auftretenden endothelialen Dysfunktion hin. MRP 1 stellt somit einen neuen Ansatzpunkt in der Behandlung der durch Diabetes ausgelösten vaskulären Dysfunktion dar. / Vascular complications and atherosclerosis are common in patients with diabetes. An increased production of reactive oxygen species contributes to endothelial dysfunction in diabetes. A major cellular defense against reactive oxygen species is Glutathione. The multidrug resistance associated protein 1 is the main transporter of oxidized glutathione in endothelial cells. Blockade of MRP 1 prevents endothelial cell dysfunction induced by reactive oxygen species. Diabetes was induced in 12 week old male MRP 1-/- mice or corresponding FVB background wildtype mice by injection of streptozotocin. Eight weeks thereafter endothelium-dependent vasorelaxation was blunted in isolated thoracic aortae. In aortae from diabetic mice lacking MRP 1, endothelium-dependent vasorelaxation was only mildly impaired. STZ induced diabetes increased aortic superoxide and hydrogen peroxide production in wildtype animals, while in aortae from MRP 1-/- mice the reactive oxygen species production was nearly unchanged by diabetic conditions. Aortic levels of reduced glutathione were diminished in diabetic FVB. Glutathione levels did not change in diabetic MRP 1-/- mice. These data indicate that MRP 1 plays an important role for endothelial dysfunction and reactive oxygen species production in diabetes and under conditions of high glucose. MRP 1 therefore may represent a therapeutic target in treatment of diabetes induced vascular dysfunction.

Une présence en excès d'espèces réactives oxygénées induit un déséquilibre redox cellulaire pouvant conduire à des pathologies liées au stress oxydatif, notamment les pathologies cardiovasculaires. Connue et étudiée pour ses propriétés antioxydantes, l’astaxanthine, molécule de la famille des caroténoïdes, présente un intérêt thérapeutique potentiel. Cependant, sa structure chimique lui confère un caractère hydrophobe ainsi qu’une sensibilité à l’air, à la lumière et à la chaleur. Dans cette thèse, tout d’abord, un système de complexation de l’astaxanthine avec l’hydroxypropyl-b-cyclodextrine a été élaboré (CD-A). Nous démontrons que cette complexation améliore la stabilité de l’astaxanthine en solution aqueuse tout en préservant ses activités antioxydantes, mesurées par des méthodes chimiques et biologiques. L’action du CD-A semble être médiée par les voies de signalisation PTEN/AKT, Nrf2/OH1/NQO1 dans des cellules endothéliales soumises au stress oxydatif. Puis, afin de libérer l’astaxanthine in situ sur le site du stress, nous avons élaboré deux systèmes de type matriciel en PVA/dextrane ou en pullulane/dextrane chargés en CD-A. Nous avons évalué, comme preuve de concept, la faisabilité de ces dispositifs pour le traitement local de la pathologie d’ischémie/reperfusion. Les patchs de PVA/dextrane/CD-A ont montré une bonne compatibilité in vitro, ainsi qu’une grande stabilité et tenue mécanique sans modification des propriétés antioxydantes. Leur biocompatibilité in vivo et suturabilité au muscle cardiaque ont aussi été étudiées. Le deuxième système à base de pullulane/dextrane/CD-A a été évalué in vitro et in vivo dans un modèle d’ischémie/reperfusion du membre inférieur à différentes périodes d'implantation. Les résultats ont montré l’activation d’un mécanisme de défense normal lié à la présence d’un matériel étranger et une diminution de la translocation du Nrf2 pouvant indiquer un effet protecteur dans les tissus traités par le CD-A. Ce manuscrit présente des arguments en faveur du potentiel thérapeutique de systèmes de libération d’astaxanthine agissant au niveau du stress oxydatif lié aux pathologies cardiovasculaires. / An over concentration of reactive oxygen species induces a redox imbalance within the cell inducing oxidative tissue damage and leading to oxidative stress related diseases, particularly cardiovascular pathologies. Astaxanthin, a well-known and studied antioxidant molecule, member of the xanthophyll carotenoid family, presents an important therapeutic potential. However, the chemical structure confers to astaxanthin a hydrophobic character and renders it susceptible to air, light and temperate degradation. During this thesis, a carrier system based on astaxanthin inclusion within hydroxypropyl-β-cyclodextrin(CD-A) was developed. We demonstrate that after astaxanthin inclusion, not only its stability was enhanced by also the antioxidant scavenging capabilities were preserved, confirmed by chemical and biological tests. The action of CD-A seems to be mediated by PTEN/AKT, Nrf2/OH1/NQO1 signaling pathways of endothelial cells submitted to oxidative stress. Then, two systems based on PVA/dextran and Pullulan/Dextran loaded within CD-A were evaluated for astaxanthin in situ delivery in the stressed environment. The feasibility of using these systems in the local treatment of ischemia/reperfusion injury was evaluated as a proof of concept. PVA/Dextran patches showed good in vitro compatibility, high mechanical and stability properties, while preserving CD-A antioxidant capabilities, also the path suturability to the cardiac muscle and the in vivo biocompatibility were studied. The second system based on pullulan/dextran scaffolds were evaluated in vitro and in vivo in an ischemic/reperfusion model at different implantation periods. Results showed an inner body defense mechanism to foreign materials. Additionally, the Nrf2 translocation could indicate a protective effect of CD-A in treated tissues. This manuscript provides a support evidence of the therapeutic potential of CD astaxanthin delivery system, to act against oxidative stress linked to cardiovascular conditions.

This thesis presents an experimental and theoretical study of the material and structural behaviour of a Steel-Fibre reinforced Reactive Powder Concrete (SF-RPC). The experimental program consisted of three phases. Phase 1 involved the development of a design mix for use throughout the remainder of the study. Phase 2 consisted of an in-depth investigation into the material properties of the mix. The final phase of the experimental component was the testing of 16 plain and prestressed SF-RPC beams. Twelve beams were tested under short-term loading to determine their cracking and ultimate moment capacity. The remaining 4 beams were used to investigate the time-dependent flexural behaviour of prestressed SF-RPC slabs. The material properties were measured using a range of short-term tests and included the compressive and flexural behaviour, static chord modulus of elasticity and crack mouth opening. In addition to the short-term tests, investigation into the time-dependent material behaviour was undertaken and included the creep and shrinkage characteristics of the material. The response of the material to various curing conditions was also investigated. The structural behaviour investigated included the short-term flexural moment-curvature response and load-deflection behaviour of beams and slabs along with the crack patterns of both plain and prestressed SF-RPC members. In addition to the investigations into the short-term flexural behaviour, a study into the time-dependent flexural behaviour was also undertaken. There are currently 2 available models for predicting the flexural response of plain and prestressed RPC cross-sections. The analytical phase of this investigation involved an evaluation of these models. Based on the experimental findings and analysis, a modified model was proposed for calculating the short-term flexural behaviour of plain and prestressed SF-RPC beams. The applicability of an age-adjusted effective modulus method for calculating the time-dependent deformations of prestressed SF-RPC slabs under various levels of sustained loads was also evaluated and found to be adequate with minor refinements.

This study examined the concept of using a reactive blending process to develop new polymeric additive systems. The objective was to investigate the potential of using a reactive processing technique as a means to bond additives to functional polymers, to create “in situ” bonds between functional groups present on the polymers and those present on the additives. The work is reported in two parts; the first part studied the bonding of colorants to functional polyolefins and the second part investigated the bonding of UV stabilisers to functional polyolefins. The research was completed with the long term objective that the approach should offer alternative additives to conventional non-bonded systems for use in polypropylene. An ethylene ionomer was utilised for the bonding of dyes, this was chosen for its optical clarity and chemical functionality. Polyethylene methacrylic acid (EMAA) ionomers and methine dyes were blended in the melt phase using an internal mixer to produce bright intrinsically colored polymers. Fourier transform infrared spectroscopy (FTIR) in transmission mode was used to assess the bonding of the dye to the ionomer. Bonding resulted through electrostatic interactions between carboxylate groups on the ionomer and cations on the dye molecules. The reactive blending process also resulted in a change in the chromophoric structure of the dye. The bonded system was compared to a system whereby no bonding between the methine dye and polymer was expected. In the later system the methine dye was blended with polyethylene using an internal mixer. From FTIR results no interaction was observed between the dye and polyethylene in this system. This was supported by microscopic analysis that showed that the dye was present in the polyethylene as a dispersion. The second stage of research focussed on the UV stabilisation of polyolefins. A melt reaction was explored between polypropylene functionalised with maleic anhydride (PP-g-MA) and an alkoxyamine hindered amine light stabiliser (NOR-HALS) with hydroxyl functionality. The technology proposed is based upon the reaction between the carboxylic acid groups of maleated polypropylene and hydroxyl groups of a specific NOR-HALS (Tinuvin 152). The efficiency of the modification was assessed using FTIR to verify the esterification reaction between the NOR-HALS and the maleated polypropylene. This reaction resulted in the grafting of a pendant UV stabiliser to the polypropylene through an ester linkage. A twin-screw extruder (TSE) was used to complete this study. A larger quantity of material could be produced using a TSE compared to the colorant system where an internal mixer was used. Samples of the reactively blended materials were exposed to UV radiation for a maximum time period of three hundred hours to assess the resulting stability of the materials. Diffuse reflectance FTIR (DRIFT) spectroscopy and X-ray photoelectron spectroscopy (XPS) provided an effective means to study oxidative degradation. IR spectroscopic measurements were used to determine the effectiveness of HALS in inhibiting the photo-oxidation of maleic anhydride grafted polypropylene. The inhibition was quantified by measuring the formation of carbonyl groups, with and without HALS bonded to the polymer, at fixed exposure times of UV radiation. DRIFT and XPS analysis confirmed that stabilised samples oxidised less, as indicated by the lower carbonyl index values and O1s / C1s ratios. These findings were complemented by results from Charpy impact tests. The mechanical property results indicated that the longevity of the materials with UV stabilisers grafted to them exceeded the PPg- MA system where there was no stabiliser present. Visible spectrophotometry was used to assess the colour of the polymeric samples and change in colour following exposure to UV radiation. Samples with bonded HALS demonstrated greater colour stability than control samples. The microstructure of the polymer surfaces was viewed using scanning electron microscopy (SEM). The polymeric samples demonstrated resistance to crazing when the NOR-HALS were bonded to the polymer. For both the colorant and UV stabiliser areas of research, thermal properties of the materials were assessed using differential scanning calorimetry (DSC). It was found that increasing the additive concentration in the polymer resulted in an increase in the temperature of crystallisation (Tc). Melt flow index can indicate if any change in molar mass had occurred during processing. An increase in melt flow index values (MFI) was observed when additive loading increased which suggested that degradation of the polymer had occurred during processing. In summary, reactive processing showed considerable promise as a means to bond additives to a functional polypropylene.

<p>We are working on the development and design of an approach to agents that can reason, react to the environment and are able to update their own knowledge as a result of new incoming information. In the resulting framework, rational, reactive agents can dynamically change their own knowledge bases as well as their own goals. An agent can make observations, learn new facts and new rules from the environment, and then update its knowledge accordingly. The knowledge base of an agent and its updating mechanism has been implemented in Logic Programming. The agent’s framework is implemented in Java. </p><p>This aim of this thesis is to design and implement an architecture of a reactive, rational agent in both Java and Prolog and to test the interaction between the rational part and the reactive part of the agent. The agent architecture is called RR-agent and consists of six more or less components, four implemented in Java and the other two are implemented in XSB Prolog. </p><p>The result of this thesis is the ground for the paper “An architecture of a rational, reactive agent” by P. DellAcqua, M. Engberg, L.M. Pereira that has been submitted.</p>

<p><p><p>This study aimed to identify some of the strategies students used when pronouncing unfamiliar words. Questionnaires were handed out to 94 students in the 9th grade in a medium-sized Swedish town. In addition, two teachers and 13 students were interviewed. The results indicate that the students had acquired some basic knowledge about the English sound system from phonetic training in their past education. However, there seemed to be a tendency among the students to use the trial-and-error strategy to a larger extent than using tools such as phonetic transcription in order to figure out the pronunciation of a word. The results also show that the teachers did not teach planned lessons on pronunciation, but instead it was more common that they responded to errors made by students. In conclusion, the results show that the students' knowledge in pronunciation in general was limited. In addition, there seemed to be a connection between the way the students and the teachers approached pronunciation and the student's ability to solve pronunciation issues.</p><p> </p><p> </p><p> </p></p></p>

This study investigated the relations between teacher-rated reactive and proactive aggression and self-ratings of peer intimacy, peer group integration, inhibition of anger and coping with anger in children in grade 4 to grade 6 (n = 519). Grade and gender differences in the study variables were also examined. Although not significant, as predicted, there was a trend towards significance where proactive aggression increased by grade; however, contrary to predictions, the occurrence of reactive aggression did not decrease by grade. The two functions of aggression were strongly correlated with one another. Males were reported more aggressive than females and self-reported lower anger management and less peer group intimacy than females. Further, females who were rated as more reactively aggressive reported less peer group integration and peer intimacy. Males who were reported as reactively aggressive also reported less peer group integration. Reactive and proactive aggression in males was related to coping with anger.