Reactivity ratios for the homogeneous free radical initiated copolymerization of acrylonitrile and methyl acrylate were measured by NMR on isolated, low conversion copolymers and by real time in situ FTIR. The system utilized azobisisobutyronitrile (AIBN) initiator in dimethyl formamide (DMF) at 62°. The FTIR technique allowed rapid generation of extensive copolymer compositions, which permitted application of nonlinear least squares methodology for the first time to this copolymer system. Thus, reactivity ratios at the 95% confidence level were determined to be 1.29 ± 0.2 and 0.96 ± 0.2 for acrylonitrile and methyl acrylate, respectively. The results are useful for the development of acrylonitrile (<90%) melt processable copolymer fibers and films, which could include precursors for carbon fibers. / Master of Science

Gold gains many useful properties when it is formed into a nanoporous structure, but it also becomes macroscopically brittle due to flow localization and may therefore be unreliable for many applications. The goal of this work was to establish processing/structure/property relationships of nanoporous gold, discover controllable structure features, and understand the role of structure on flow localization. The nanoporous gold structure, consisting of a 3D network of nanoscale gold ligaments, was quantified with an automatic software developed for this work called AQUAMI, which uses computer vision techniques to make statistically reliable numbers of repeatable and unbiased measurements per image. AQUAMI increased the efficiency and accuracy of characterization in this work, allowed for the conduction of more experiments, and provided better confidence in morphology and size distribution of the complex NPG microstructural features. Nanoporous gold was synthesized while varying numerous processing factors such as dealloying time, annealing time, and mechanical agitation. Through the expanded scope of synthesis experiments and detailed analysis, it was discovered that the curvature of the ligaments and the distribution width of ligament diameters could be controlled through processing. In situ tensile experiments in SEM and TEM revealed that large ligaments arrested crack propagation while curved ligaments increase ductility by straightening in the tensile direction and forming geometrically required defects, which inhibit dislocation activity. Through synthesis and microstructure characterization, two new controllable structure features were discovered experimentally. In situ mechanical testing revealed the role these structures play on the deformation behavior and flow localization of nanoporous gold. / Doctor of Philosophy / Nanoporous gold contains a network of connected pores running through and between at network of solid gold ligaments or struts. It somewhat resembles the structure of coral. The nanoscale pores and ligaments give the material many useful properties. However, this structure also makes the material very fragile and unreliable in many potential application environments. The goal of this research is to investigate how the structure makes the material so fragile and look for ways the material might be made less fragile while still preserving its useful properties. The material properties are controlled through the material’s structure, which in turn is controlled by processing. To control the structure of nanoporous gold, the structure first had to be characterized. A software called AQUAMI was developed, which uses computer vision, to automatically calculate many features of the structure by looking at an image of it. This software was much faster and more accurate than making hundreds of hand measurements on each image. To find new ways to control the structure through processing, nanoporous gold was synthesized in many different conditions and then the structure was analyzed to determine the effect of each synthesis condition. It was discovered that a single specimen could be given a larger variety of ligament thicknesses by making it with a weaker acid or a smaller variety by heating the structure after forming it. Stirring during synthesis resulted in a structure with curvier ligaments. Mechanical tests were performed in electron microscopes to see how these features affected deformation. Large ligaments slowed crack propagation suggesting that a larger variety of ligament diameters could increase strength by having more large ligaments. Curved ligaments deformed more without breaking by straightening during deformation. Through this work, new ways of controlling the nanoporous gold structure were found and mechanical tests suggest that controlling these features may increase the material’s strength making it reliable in more environments

A detailed study was made in this doctoral thesis on the development and differentiation of the vertebrate pituitary gland, with the aim to establish a fate map in Rathke's pouch of the origin of different hormone producing cells present in the adult pituitary gland, that explain if the differences observed in the distribution pattern of different hormone producing cells in the adult is the consecuence of differences in their development. For this reason, the study was made in two vertebrate groups, Mammals and Avian, that present notable differences in their hormone producing cell distribution patterns. The results allowed us to conclude that the origin of different hormone producing cells in Rathke’s pouch determine their definitive distribution in the adult gland. At the same time, the relationship between proliferation and differentiation was studied, showing us that after differentiation, hormone producing cells continue proliferating with a low rate, contributing to the establishment of differentiated populations. Using immunochemicals and in situ hidridization techniques, the expression of different molecules such as hypothalamic releasing factors; different peptides, whose role as modulators in different pituitary axis have been proposed in the adult animal; different calcium binding proteins and transcription factors in relation to the differentiation of different hormone producing cells, was also studied in this work, allowing us to establish different relationships between some of these factors and specific aspects of the development and differentiatin of the pituitary gland.

En la presente tesis doctoral se ha estudiado el mecanismo de la reacción de acilación de sustratos aromáticos utilizando como catalizadores zeolitas con diferente topología. La combinación de la RMN de sólidos in situ con cálculos teóricos ha permitido identificar posibles intermedios formados por reacción de los agentes acilantes (cloruro de acetilo, ácido acético y anhídrido acético) con los centros ácidos Brønsted de la zeolita. Los resultados obtenidos muestran que las zeolitas de poro pequeño son menos activas en la reacción de acilación de anisol, probablemente debido a restricciones en la difusión de los reactivos. Se ha observado además que el producto de reacción, p-metoxiacetofenona, permanece fuertemente adsorbido en los centros Brønsted, lo que podría originar la desactivación del catalizador. Esta misma metodología se ha aplicado para el estudio de la reacción de transposición de Beckmann en zeolitas y materiales mesoporosos con centros activos de distinta naturaleza, centros ácidos Brønsted con diferente fortaleza ácida, y grupos silanoles. El uso de dos oximas de diferente tamaño molecular (ciclohexanona y ciclododecanona oximas) ha permitido establecer que la reacción de transposición de ciclohexanona oxima en -caprolactama tiene lugar en el interior de los poros de las zeolitas del tipo MFI, y no en la superficie externa del cristal. Del mismo modo, se ha determinado la actividad catalítica y selectividad hacia la lactama de los diferentes tipos de centros estudiados. Por otra parte, en esta tesis se ha investigado la reacción de transposición de Beckmann en líquidos iónicos (LIs): 1-butil-3-metilimidazolio hexafluorofosfato, 1-Butil-3-metilimidazolio tetrafluoroborato, 1-Butil-2,3-dimetilimidazolio hexafluorofosfato, bromuro de 1-butil-3-metilimidazolio tetrafluoroborato y 4-metil-1-butilpiridinio hexafluorofosfato. El estudio se ha abordado utilizado diferentes técnicas analíticas y espectroscópicas, incluyendo la / Lezcano González, I. (2011). Aplicación de la resonancia magnética nuclear (RMN) al estudio de procesos catalíticos sostenibles: transposición de Beckmann y acilación de sustratos aromáticos [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/18258

The effects of lithology, fracturing, and gouge zone mineralization on the geophysical properties of fault zones are not very well understood. In situ seismic data collected over the exhumed San Gregorio Fault at Moss Beach, CA were used to relate in situ compressional wave velocity to internal fault zone properties. This active strike-slip fault is exposed in cross section on an uplifting and actively eroding wave-cut platform. It cuts shallow marine sediments that have been buried to depths of a few kilometers. The unweathered exposure containing seawater makes it a unique analog of subsurface faults. Previous structural analysis over this exposure observed damage caused by faulting over a ~100 m wide zone in cross-section. The fault zone is centered at a 10-17 m wide clay-rich fault core flanked by a ~30 m wide brecciated gouge zone. These gouge zones are bordered on either side by 30-40 m wide fractured zones. Resolving to a scale of a few meters, the seismic survey produced a continuous P-wave velocity profile analogous to a horizontal well log across the fault. Lateral variations in the velocity profile correlate exactly to previously mapped fault zone structure. The clay core and adjacent brecciated gouge create a ~50 m wide very low velocity zone, 25-50% slower than the surrounding host rock. Fractured bedrock on either side of the core causes a wider zone of 5-10% slow velocity, for a total fault signature ~100 m wide. Fault parallel fracture anisotropy was observed in the fractured zones, but surprizingly anisotropy was not observed in the strongly foliated gouge zones. The field measurements differ significantly from laboratory measurements at zero pressure and in some cases from expected values for saturated rock of this porosity, perhaps due to biased rock sampling, the long wavelength effects of macrofractures, frequency dispersion, and partial saturation. The velocity profile is similar in width and consistent in velocity contrast to low S-wave velocity zones derived from fault zone guided waves in other strike-slip faults. The traveltime delay across the fault zone is not large enough to cause the 2-3 km wide crustal low velocity zones modeled by refraction studies. Synthetic reflection seismograms in the typical frequency range show that the fault zone acts as a thick bed or as a constructively interfering thin bed. The models suggest that very large reflection coefficients observed across accretionary prism faults can be explained by fracturing, brecciation and clay content without elevated pore pressures. Comparison with a refraction study across the Punchbowl Fault shows a similar structural zonation of these two well-studied examples of brittle fault zones. This suggests that high-resolution seismic velocity models can be used to directly interpret internal deformation structure of brittle faults. / Master of Science

Reaction synthesis is a processing technique where the thermal activation energy needed to form a compound is provided by the exothermic heat of formation of the thermodynamically stable product. This type of synthesis has been used to form a variety of ceramics, intermetallics, and in-situ composites. In this work, the effects of changing the stoichiometry of the titanium aluminide matrix, and the effects of extrinsic reaction variables on the behavior of the reaction were studied and compared to theoretical predictions. It was shown that changing the stoichiometry of the titanium aluminide did have an effect on the measured heat of reaction; however this did not match the prediction. Changing the extrinsic variables of titanium and aluminum particle sizes also showed a significant effect on the behavior of the reaction. / Master of Science

Yes / Liquid crystal is a new emerging biomaterial. The physical property of liquid crystal plays a role in supporting the adhesion of cells. Nano and microball indentation techniques were applied to determine the elastic modulus or viscoelasticity of the cholesteryl ester liquid crystals in the culture media. Nano-indentation results (108 ± 19.78 kPa, N = 20) agreed well with the microball indentation (110 ± 19.95 kPa, N = 60) for the liquid crystal samples incubated for 24 hours at 37o C, respectively. However, nanoindentation could not measure the modulus of the liquid crystal (LC) incubated more than 24 hours. This is due to the decreased viscosity of the liquid crystal after immersion in the cell culture media for more than 24 hours. Alternatively, microball indentation was used and the elastic modulus of the LC immersed for 48 hours was found to decrease to 55 ± 9.99 kPa (N = 60). The microball indentation indicated that the LC did not creep after 40 seconds of indentation. However, the elastic modulus of the LC was no longer measurable after 72 hours of incubation due to the lost of elasticity. Microball indentation seemed to be a reliable technique in determining the elastic moduli of the cholesteryl ester liquid crystals. / Science Fund Vot. No. S024 or Project No. 02- 01-13-SF0104 and FRGS Vot. No. 1482 awarded by Malaysia Ministry of Education

No / Spatial genome organization in the cell nucleus plays a crucial role in the control of genome functions. Our knowledge about spatial genome organization is relying on the advances in gene imaging technologies and the biochemical approaches based on the spatial dependent ligation of the genomic regions. Fluorescent in situ hybridization using specific fluorescent DNA and RNA probes in cells and tissues with the spatially preserved nuclear and genome architecture (3D-FISH) provides a powerful tool for the further advancement of our knowledge about genome structure and functions. Here we describe the 3D-FISH protocols allowing for such an analysis in mammalian tissue in situ including in the skin. These protocols include DNA probe amplification and labeling; tissue fixation; preservation and preparation for hybridization; hybridization of the DNA probes with genomic DNA in the tissue; and post-hybridization tissue sample processing.

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No description available.