L’architecture des biomatériaux de comblement osseux à un réel impact sur l’activité cellulaire, la vascularisation et la diffusion de facteurs de croissance. Dans un premier temps, différentes membranes de polystyrène (PS) composées de fibres alignées ou aléatoires ont été étudiées. Elles sont non biodégradables et pourraient servir de supports pour la régénération de larges défauts osseux. Nous avons montré la cytocompatibilité in vitro des membranes en analysant l’adhésion, la prolifération et la différenciation cellulaire. Ensuite, des membranes de PS ont été enrichies de grains de β-TCP ou de nanoparticules d’or. Nous les avons implantées dans un modèle de défaut crânien de taille critique chez la souris. L’addition de β-TCP a stimulé la repousse osseuse grâce à la grande bioactivité des céramiques. Les membranes ont été biotolérées, les fibres ont été encapsulées dans l’os néoformé mais également dans un tissu conjonctif dense. Les nanoparticules d’or immobilisées sur des fibres ont migré dans l’os ou ont été phagocytées. Dans un second temps, différentes formulations de granules poreux de β-TCP ont été analysées par nanotomographie aux rayons X. L’architecture macroporeuse des granules varie inversement avec la concentration en β-TCP. Les faces internes montrent une grande hétérogénéité de minéralisation. Pour mimer les conditions d’utilisation en chirurgie maxillo-faciale, les granules ont été empilés dans des tubes. Nous avons montré que l’architecture des empilements de granules dépendait de leur forme. L’empilement de granules commerciaux (contenant12,5g de β-TCP) mime l’architecture naturelle et les propriétés physiques de l’os. / The architecture of bone filling biomaterials has a real impact on cellular activity, vascularization and diffusion of growth factors. As a first step, different polystyrene (PS) scaffolds composed of aligned or random fibers were studied. They were non-biodegradable and could be used as supports for regeneration of large bone defects. We showed the in vitro cytocompatibility of the scaffolds by analyzing cell adhesion, proliferation and differentiation. Then, polystyrene scaffolds were enriched with β-TCP grains or gold nanoparticles. We implanted them in a model of critical size defect in mouse calvaria. Addition of β-TCP stimulated bone regrowth due to the high bioactivity of the ceramics. Scaffolds were biotolerated, fibers were encapsulated in the newly formed bone and also in a dense connective tissue. The gold nanoparticles immobilized on fibers migrated into the bone or were phagocytized. As a second step, different formulations of porous granules of β-TCP were analyzed by X-ray nanotomography. The macroporous architecture of granules varies inversely with the concentration of β-TCP. The internal faces howed a great heterogeneity of mineralization. Tomimic the conditions in maxillofacial surgery, granules were stacked in tubes. We have shown that the architecture of the granules depends on their shape.The stacks of commercial granules (containing 12.5 g ofβ-TCP) mimicked the natural architecture and physical properties of bone.

Dan Beaty (1937-2002) was a prolific composer, pianist, researcher, educator, and writer. His large compositional output included chamber works, choral works, songs, orchestral pieces, electronic music, and keyboard works. Beaty was well versed in traditional Western music as well as the more avant-garde and perplexing idioms of the twentieth century. Beaty's compositions reflect the many fascinating, if not always popular, musical trends of his time. His music encompasses styles from serial to jazz, shows compositional influences from Arnold Schoenberg to Indonesian music, and demonstrates thought-provoking and highly intellectual craftsmanship. This document explores several of Beaty's songs through a discussion of the composer's life and compositional process. Songs included in this document are Three Weeks Songs, October, November, A Sappho Lyric, Love Song, That Night When Joy Began, and War Lyrics. This document was written to accompany the author's DMA Lecture-Recital at the University of North Texas. Unfortunately, Beaty's vocal music was never published and is mostly unknown. One goal of the project was to initiate interest in Beaty's songs. Through this document, Lecture-Recital, and additional performances, considerable strides have been made to bring Beaty's songs to new audiences throughout the United States. In addition, the author has received permission from the Beaty family to publish Dan Beaty's songs.

El problema más frecuente en los muros de albañilería se presenta en su deterioro debido a la exposición prolongada a la humedad que se manifiesta mediante daños drásticos en las unidades de albañilería sin recubrimiento, los cuales pueden ser pulverización, descamación y agrietamiento. En la actualidad, en la ciudad de Cusco, el sistema estructural de albañilería es el más empleado con un 96.67% de edificaciones usándolo. Estos se exponen a la humedad cuando la temperatura fluctúa entre congelamiento y descongelamiento, generado durante la temporada de lluvias y heladas manifestadas en la ciudad. Esta investigación se realizó mediante un proceso de cuatro fases. Primero, se realizaron los diseños de las mezclas de mortero de junta y revestimiento con proporciones de 5%, 7%, 10% y 30%, 40% y 50% de sustitución de agregado fino por perlas de poliestireno expandido, respectivamente. Segundo, se determinó la durabilidad de los morteros por medio de la resistencia a compresión de las muestras sometidas a heladicidad. En la tercera fase, luego de determinar los morteros con porcentajes adecuados, con la finalidad de validar las características de la propuesta, se elaboraron pilas de ladrillos para someterlos a ensayos de heladicidad y analizar el comportamiento en conjunto de los elementos de un muro de albañilería. Por último, se propuso un proceso constructivo para lograr rendimientos similares a los ya existentes en obra y se realizó un análisis de costo – beneficio, el cual compara la aplicación del mortero modificado y convencional en un muro de albañilería. Los resultados indican una disminución en la resistencia a compresión de 14.76 kg/cm2 en los prismas convencionales y un aumento de 1.88 kg/cm2 en prismas con mortero modificado. Lo cual indica que los prismas modificados, en ladrillo y mortero, incrementan su resistencia en un 4%. / The most frequent problem in masonry walls is in their deterioration, due to the prolonged exposure to moisture, that is manifested by drastic damage in the uncoated masonry units, which can be pulverized, flaking and cracking. Currently, in the city of Cusco, masonry constructions represent 96.67% of the total of constructions, and the presence of moisture in the walls occurs when there is variation of temperatures between the freezing and thawing cycles, generated by the rainy and freezing season that manifests in the city. This research was conducted through a four-step process. First, we made the designs of the joint and coating mortar mixtures with ratios of 5%, 7%, 10% and 30%, 40% and 50% substitution of fine aggregate with expanded polystyrene beads, respectively. Second, the durability of the mortars was determined by the compressive strength of the samples subjected to frost. In the third stage, after determining the mortars with appropriate percentages, to validate the characteristics of the proposal, Bricks piles were developed for ice-freezing testing and for analyzing the behavior of the elements of a masonry wall. Finally, a constructive process was proposed to achieve yields like those already existing on site and a cost - benefit analysis was carried out, which compares the application of modified and conventional mortar on a masonry wall. The results indicate a decrease in compressive strength of 14.76 kg/cm2 in conventional prisms and an increase of 1.88 kg/cm2 in prisms with modified mortar. This indicates that the modified prisms, in brick and mortar, increase their resistance by 4%. / Tesis

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<p> The effect of capillary dimensions on the die swell of molten polymers is investigated. Low and high density polyethylene, polypropylene, polystyrene are used to make investigation It is found the die swell decreases vii th L/D. The plot of die swell index (d/D) vs. L/D has the shape of anexponential decay curve. </p> <p> Bagley's decaying equation is used to fit the data. The effect of Deborah number on die swell phenomenon is also studied. 'I'he relationship between the recoverable shear strains of infinitely long capillary and the one with dimensions ratio L/D is obtained. This relationship could be used to estima te the die swell of short capillary from its value at equilibrium and polymer characteristics. </p> / Thesis / Master of Engineering (MEngr)

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No / Microcarrier cell culture systems provide an attractive alternative to the conventional monolayer cell culture for cell amplification, due to their high surface area-to-volume ratio. Unlike enzymatic methods for removing cells from microcarriers after cell culture, which can lead to irreversible damage of the cells, microcarriers which release cells by temperature adjustment have been developed. This was achieved by grafting a temperature-responsive polymer, poly(N-isopropylacrylamide) (PNIPAAm), on the microcarrier surface. This review comprehensively presents various methods to prepare such thermo-responsive microcarriers based on PNIPAAm. These methods include the grafting-to technique, grafting-from technique, grafting-through technique, along with methods leading to PNIPAAm hydrogel beads, seeded polymerization, and non-covalent adsorption. The methods for controlling PNIPAAm grafting density, molecular weight and molecular architecture are also outlined. Further, the efficiency of cell attachment, proliferation and thermally-induced detachment of such thermo-responsive microcarriers is introduced and compared. (C) 2015 Elsevier Ltd. All rights reserved.

Carbon-based materials are poised to be an important class of 21st century materials, for bio-medical, bio-electronic, and bio-sensing applications. Diamond and polymers are two examples of carbon-based materials of high interest to the bio-materials community. Diamond, in its conductive form, can be used as an electrochemical bio-sensor, whilst its nanoparticle form is considered a non-inflammatory platform to deliver drugs or to grow neuronal cells. Polymers, especially when chemically modified, have been used extensively in biological environments, from anti-microbial use to drug delivery. The large-scale use of either material for biological use is limited by two factors: ease of chemical modification and the paucity of knowledge of their surface chemistry in aqueous media. This thesis addresses aspects of both these issues. The first study reported is an in situ study of the adsorption dynamics of an exemplar globular protein (bovine serum albumin, BSA) on nanodiamond using the relatively novel quartz crystal microbalance with dissipation (QCM-D) technique. For the first time, QCM-D enabled the detailed study of protein dynamics (i.e. kinetics, viscoelastic properties, overlayer structure, etc.) onto nanodiamond thin films having various surface chemistry and roughness. The dynamics of protein adsorption is found to be sensitive to surface chemistry at all stages of adsorption, but it is only sensitive to surface roughness during initial adsorption phases. Our understanding of the nanodiamond-biology interface is enhanced by this study, and it suggests that QCM-D is useful for the study of the surface chemistry of nanoparticle forms of inorganic materials. A second study concerns a novel surface functionalization scheme, based on carbene and azo-coupling chemistry, which has been recently introduced as a practical, facile method for modifying the surfaces of polymers. Using modern surface characterization techniques, it is demonstrated that a chemical linker can be attached to polystyrene surfaces using carbene-based chemistry, and that further chemical functionality can be added to this chemical linker via an azo-coupling reaction. In situ studies of protein dynamics at these interfaces were conducted using QCM-D, thus enabling a link between specific protein behaviour and the polymer surface chemical termination chemistry to be made. A third area of study of investigates the use of diamond electrodes as a bio-sensor for dopamine under physiological conditions. For these conditions, ascorbic acid interferes with the dopamine oxidation signal, in ways that render the two signals irresolvable. Various modifications are used in attempts to reduce this interference, including: small and large cathodic treatments, grafting of electro-active polymers, addition of carbon nanotubes, and hydrogen plasma treatment. Those modifications leading to the hydrogen-termination of diamond are shown to work the best. Notably, hydrogen plasma treatment effects the complete electrochemical separation of dopamine and ascorbic acid at a diamond electrode. This is the first time this has been accomplished without adding non-diamond materials to the diamond electrode surface.

Une compréhension approfondie et un meilleur contrôle de l'auto-assemblage des copolymères diblocs (séquencés) et de leurs complexes à l'interface air/eau permettent la formation contrôlée de nanostructures dont les propriétés sont connues comme alternative à la nanolithographie. Dans cette thèse, des monocouches obtenues par les techniques de Langmuir et de Langmuir-Blodgett (LB) avec le copolymère dibloc polystyrène-poly(4-vinyl pyridine) (PS-PVP), seul ou complexé avec de petites molécules par liaison hydrogène [en particulier, le 3-n-pentadécylphénol (PDP)], ont été étudiées. Une partie importante de notre recherche a été consacrée à l'étude d'une monocouche assemblée atypique baptisée réseau de nanostries. Des monocouches LB composées de nanostries ont déjà été rapportées dans la littérature mais elles coexistent souvent avec d'autres morphologies, ce qui les rend inutilisables pour des applications potentielles. Nous avons déterminé les paramètres moléculaires et les conditions expérimentales qui contrôlent cette morphologie, la rendant très reproductible. Nous avons aussi proposé un mécanisme original pour la formation de cette morphologie. De plus, nous avons montré que l'utilisation de solvants à haut point d’ébullition, non couramment utilisés pour la préparation des films Langmuir, peut améliorer l'ordre des nanostries. En étudiant une large gamme de PS-PVP avec des rapports PS/PVP et des masses molaires différents, avec ou sans la présence de PDP, nous avons établi la dépendance des types principaux de morphologie (planaire, stries, nodules) en fonction de la composition et de la concentration des solutions. Ces observations ont mené à une discussion sur les mécanismes de formation des morphologies, incluant la cinétique, l’assemblage moléculaire et l’effet du démouillage. Nous avons aussi démontré pour la première fois que le plateau dans l'isotherme des PS-PVP/PDP avec morphologie de type nodules est relié à une transition ordre-ordre des nodules (héxagonal-tétragonal) qui se produit simultanément avec la réorientation du PDP, les deux aspects étant clairement observés par AFM. Ces études ouvrent aussi la voie à l'utilisation de films PS-PVP/PDP ultraminces comme masque. La capacité de produire des films nanostructurés bien contrôlés sur différents substrats a été démontrée et la stabilité des films a été vérifiée. Le retrait de la petite molécule des nanostructures a fait apparaître une structure interne à explorer lors d’études futures. / Deeper understanding and control of the self-assembly of diblock copolymers and their complexes at the air/water interface allow the formation of nanopatterns with known properties to provide a competitive substitute to nanolithography. In this dissertation, Langmuir and Langmuir-Blodgett (LB) monolayers obtained from polystyrene-poly(4-vinyl pyridine) diblock copolymers (PS-PVP), alone and hydrogen-bonded by various small molecules [particularly, 3-n-pentadecylphenol (PDP)], have been extensively investigated. A major part of the research was devoted to the study of an uncommon monolayer pattern that we term the nanostrand network. LB monolayers consisting of nanostrands have sometimes been reported in the literature, but are often coexistent with other morphologies, which is not useful for potential applications. We have determined the molecular parameters and experimental conditions that control this morphology, making it highly reproducible, and have proposed a novel mechanism for the formation of this morphology. In addition, we have shown that the use of high-boiling spreading solvents, not usually used for Langmuir film preparation, can improve the nanostrand order. By investigation of a wide range of PS-PVP’s with various block ratios and molecular weights, with and without PDP present, we have established the composition dependence of the main LB morphology types (planar, nanostrand, nanodot) and the influence of each type on spreading solution concentration. This led to an extensive discussion concerning the mechanisms of morphology formation, including kinetic, molecular association, and dewetting contributions. We have also shown that the isotherm plateau transition for nanodot-forming PS-PVP/PDP is related to an order–order transition that occurs simultaneously with PDP reorientation, both aspects being clearly observed by AFM. These studies also form the basis for the use of ultrathin PS-PVP/PDP films as templates. The ability to produce well-controlled nanopatterned films on various substrates has been demonstrated, and film stability has been verified. Removal of small molecules from the nanostructures has revealed the appearance of new substructure of interest for further study.