Gas-expanded liquids (GXLs) are a unique class of tunable solvents with unlimited potential. A wide range of solvent properties and solvent interactions and complexes are possible by adjusting the amount of the gas component (in situ) or changing the organic liquid. Aside from solvent tunability, there are environmental and processing benefits to using GXLs. Organic solvent use is decreased, the gas component can be vented off facile separations, and the gas can act as an antisolvent for selective solute precipitation. As a result there are numerous reaction and extraction schemes and materials processing applications that could benefit from GXL use. Unfortunately, important molecular-level details that can drive a chemical process are largely unknown and limit GXL use in industrial and specialty applications. The work presented in this uses a synergistic study of experiments and computer simulations to explore solvation processes and molecular interactions in GXLs and the effects on macroscopic observables like spectroscopy, transport, and reactions. Steady-state solvation of a laser dye is studied with spectroscopy (UV/vis and fluorescence) and molecular dynamics simulations (MD). Both experiment and theory show that organic enrichment occurs in the vicinity of the solute called the cybotactic region. Subsequently, the solvent dynamics arising by electronically perturbing the solute are studied with MD simulation. Unexpected dynamics are observed and are dependent on the organic component and gas composition. The diffusion of heterocyclic compounds is studied with MD simulations and compared to the Taylor-Aris diffusion study of former group members. The experiments and simulations do not agree, but solvent structures obtained by simulation are shown to provide valuable insight into solvent-dependent absorption spectroscopy, or solvatochromism. Finally, dissociation constants of alkylcarbonic acids that form in situ in CO2/alcohol mixtures are presented from spectroscopic measurements. Spectroscopic techniques to measure dissociation constants are well known; however, the high-pressure and multiple equilibria associated with alkylcarbonic acids hinder straight-forward measurement and analysis.

The purpose of this prospective, randomized, controlled clinical investigation is to evaluate the performance of the Motorized Ridge Expanders (MRE), and to compare its results with the ones achieved utilizing lateral ridge augmentation (LRA). Eight subjects with bilateral ridge deformities were selected. One technique was used on the right site and the other on the left site. Implants were placed six months after the bone augmentation procedures. All the measurements were recorded at 2 and 5 mm from the most coronal part of the crest. The augmentation achieved with both techniques was statistically significant, 1.2 mm in the LRA, 1.5 mm in MRE at 2 mm from the crest; 1.5 mm and 1.6 mm respectively at 5mm from the crest. The differences between the two techniques were statistically insignificant. The amount of expansion achieved in the MRE site appears to be negatively correlated (P-Value <0.05) with the thickness of the cancellous bone, and it is not affected by the thickness of the cortical plate. The MRE technique appears to be as effective as the LRA technique in augmenting the thickness of atrophic ridges. The defect treated with the MRE showed less bone width contraction during the first 6 months of healing. Histologically, the regenerated bone was vital, trabecular in nature and in direct contact with bone graft particles. / El propósito de esta investigación clínica prospectiva y aleatoria es comparar el aumento horizontal de la cresta alveolar obtenido con el uso de los expansores motorizados de cresta (EMC) y con regeneración ósea guiada (ROG). Fueron selecccionados ocho pacientes con deformidades horizontales del reborde alveolar bilaterales que iban a recibir implantes dentales. Una técnica de regeneración se utilizó en el lado derecho y la otra en el lado izquierdo, para un total de 23 muestras, 13 en el lado experimental (EMC) y 10 en el lado control (ROG). Los implantes fueron colocados seis meses después de los procedimientos de aumento óseo, y se obtuvo una muestra de hueso para estudio histológico. Todas las mediciones clínicas se registraron a los 2 y 5 mm de la parte más coronal de la cresta. El aumento logrado con ambas técnicas fue estadísticamente significativo, de 1,2 mm en la ROG y 1,5 mm con los EMC a 2 mm de la cresta; y 1,5 mm y 1,6 mm, respectivamente, a 5mm de la cresta. Las diferencias entre las dos técnicas no fueron estadísticamente significativas. La cantidad de expansión lograda en el sitio de los EMC parece tener una correlación negativa (p <0,05) con el grosor del hueso esponjoso, y no se ve afectada por el grosor de la cortical. Histológicamente se observó osteoconductividad del injerto óseo y más partículas residuales del mismo en el lado experimental. La técnica de los EMC parece ser tan eficaz como la técnica de ROG en el aumento de la anchura de las crestas atróficas. Los defectos tratados con los EMC mostraron una menor contracción del injerto óseo durante los 6 meses de cicatrización. / El propòsit d'aquesta recerca clínica prospectiva i aleatòria és comparar l'augment horitzontal de la cresta alveolar obtingut amb l'ús dels expansors motoritzats de cresta (EMC) i amb regeneració òssiaguiada (ROG). Es van selecccionar vuit pacients amb deformitats horitzontals bilaterals de la cresta alveolar on es col.locaren implants dentals. Una tècnica de regeneració es va emprar en el costat dret i l'altra a la banda esquerra, per a un total de 23 mostres, 13 al costat experimental (EMC) i 10 en el costat control (ROG). Els implants van ser col.locats sis mesos després dels procediments d'augment ossi, i es va obtenir una mostra d'os per estudi histològic.Totes les mesures clíniques es van registrar als 2 i 5 mm de la part més coronal de la cresta. L'augment aconseguit amb ambdues tècniques va ser estadísticament significatiu, de 1,2 mm a la ROG i 1,5 mm amb els EMC a 2 mm de la carena, i 1,5 mm i 1,6 mm, respectivament, a 5mm de la cresta. Les diferències entre les duestècniques no van ser estadísticament significatives. La quantitat d'expansió aconseguida en el lloc dels EMC sembla tenir una correlació negativa (p<0,05) amb el gruix de l'os esponjós, i no es veu afectada per el gruix de la cortical. Histològicament es observar osteoconductividad l'empelt ossi i més partícules residuals d'aquest en el costat experimental. La tècnica dels EMC sembla ser tan eficaç com la tècnica de ROG en l'augment de l'amplada de les crestes atròfiques. Els defectes tractats amb els EMC mostrar una menor contracció de l'empelt ossi durant els 6 mesos de cicatrització.

This qualitative study examines an asynchronous online course from a private university utilizing a template model for all online courses to provide students with consistent navigation and course structure throughout their degree program. The asynchronous online courses are purposely created using three criteria of quality course design: navigation is intuitive, information is chunked, and instructions are written clearly. A two-part usability test was conducted with three internal and three external participants. The two-part usability test focused on course navigation and examined the signaling, segmenting, and coherence principles applied to course content page layouts. Transcripts from the usability tests and observational field notes were coded through an iterative process in Nvivo. Through emic and etic coding, seven main categories were identified: user experience, cognitive load, multimedia learning principles, page design and layout attributes, course navigational attributes, course attributes and information, and participant navigational behavior. The findings for first-day navigation, general navigational behaviors, and perceptions of design elements used to implement the signaling, segmenting, and coherence principle are discussed. Course design recommendations for creating a positive usability experience and suggestions for future research are provided.

Ma thèse se situe à l'intersection de \textit {la théorie des groupes géométrique} et \textit{la théorie des groupes mesurée}. Une question majeure dans la théorie des groupes géométrique est d'étudier la classe de quasi-isométrie (QI) et la classe d'équivalence mesurée (ME) d'un groupe, respectivement. $L^p$-équivalence mesurée est une relation d'équivalence qui est définie en ajoutant des contraintes géométriques avec d'équivalence mesurée. En plus, QI est une condition géométrique. Il est une question naturelle, si deux groupes sont QI et ME, si elles sont $L^p$-ME pour certains $p>0$. Dans mon premier article, en collaboration avec R. Tessera, nous répondons négativement à cette question pour $p\geq 1$, montrant que l'extension centrale canonique d'un groupe surface de genre plus élevé ne sont pas $L^1$-ME pour le produit direct de ce groupe de surface avec $\mathbb{Z}$ (alors qu'ils sont à la fois quasi-isométrique et équivalente mesurée).Dans mon deuxième papier, j'ai observé un lien général entre la géométrie des expandeurs, defini comme une séquence des quotients finis ( l'espace de boîte) d'un groupe finiment engendré, et les propriétés mesurée theorique du groupe. Plus précisément, je l'ai prouvé que si deux <<espaces de boîte>> sont quasi-isométrique, les groupes correspondants doivent être <<mesurée équivalente uniformément >>, une notion qui combine à la fois QI et ME. Je prouve aussi une version de ce résultat pour le plongement grossière, ce qui permet de distinguer plusieurs classe des expandeurs. Par exemple, je montre que les expandeurs associé à $SL(m, \mathbb{Z})$ ne grossièrement plongent à les expandeurs associés à $SL_n(\mathbb{Z})$ si $m>n$. / My thesis lies at the intersection of \textit{geometric group theory} and \textit{measured group theory}. A major question in geometric group theory is to study the quasi-isometry (QI) class and the measure equivalence (ME) class of a group, respectively. $L^p$-measure equivalence is an equivalence relation which is defined by adding some geometric constraints with measure equivalence. Besides, quasi-isometry is a geometric condition. It is a natural question if two groups are QI and ME, whether they are $L^p$-ME for some $p>0$. In my first paper, together with R. Tessera, we answer this question negatively for $p\geq 1$, showing that the canonical central extension of a surface group of higher genus is not $L^1$-ME to the direct product of this surface group with $\mathbb{Z}$ (while they are both quasi-isometric and measure equivalent). In my second paper, I observed a general link between the geometry of expanders arising as a sequence of finite quotients (box space) of a finitely generated group, and the measured theoretic properties of the group. More precisely, I proved that if two box spaces' are quasi-isometric, then the corresponding groups must be `uniformly measure equivalent', a notion that combines both quasi-isometry and measure equivalence. I also prove a version of this result for coarse embedding, allowing to distinguish many classes of expanders. For instance, I show that the expanders associated to $SL(m,\mathbb{Z})$ do not coarsely embed inside the expanders associated to $SL_n(\mathbb{Z}$ if $m>n$.