Thesis (M.S.)--University of Texas. / Vita. Includes bibliography.

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1911. / Discrepancy in page numbering - there is no page 5. The entire thesis text is included in file. Typescript. Illustrated by authors. Title from title screen of thesis/dissertation PDF file (viewed February 26, 2009) Includes bibliographical references (p. [ii]).

Graduate

The study focuses on the effects of heat stress on <i>Serpula lacrymans</i> and <i>S. himantioides</i> (which have been previously shown to be relatively thermosensitive and thermotolerant respectively) in relation to the heat shock response. A part of this response is the production of heat-shock proteins (hsps). Comparative studies of chick embryo fibroblasts and <i>Saccharomyces cerevisiae</i> (wine strain, L-2226) were used to demonstrate possible differences between these three very distinct eukaryotic systems. The aims of the project were to determine whether <i>S. lacrymans</i> and <i>S. himantioides</i> undergo the heatshock response with respect primarily to induced thermotolerance and the production of hsps. The approach taken to establish the above was by systematic analysis of the different pathways involved in this response. Firstly, overall heat induced changes in protein and mRNA synthesis were analysed, in conjunction with the identification of specific proteins related to the heat-shock response, namely hsp60, hsp70 which have been shown in other eukaryotic systems to play key roles in this response. Secondly, immunological studies were also used to detect changes in the pattern of protein ubiquitination, which resulted from heat stress. Thirdly, changes in hsp70 mRNA were monitored by RT-PCR. The cDNA and genomic amplimer products generated by RT-PCR and PCR respectively were cloned and sequenced to identify a putative of hsp70 gene sequence. Fourthly, the AMP-activated protein kinase (AMPK) cascade has been demonstrated to be activated in response to stress and steps were made to detect and identify AMPK activity in cellular extracts of both <i>Serpula </i>species. Finally, the effect of heat upon trehalose accumulation and mobilisation during the heat-shock response was studied as there is growing evidence to link increased thermotolerance to transient increase in trehalose levels, which is now considered to be a stress metabolite.

Este trabajo busca identificar las posibles perturbaciones (shocks) que afectarían la cuenta corriente de la Argentina. A tal efecto, se analiza la transmisión de shocks y se explora su impacto sobre la inversión doméstica y la cuenta corriente, empleando para ello estimaciones econométricas y la técnica de los Vectores Autorregresivos (VAR). El análisis cubre el período 1977/97 (posterior a la Reforma Financiera). Se analizan dos tipos de shocks. Por un lado, los shocks de oferta, tal como los que surgen por cambios en la productividad total de los factores. Estos shocks pueden ser idiosincráticos o específicos del país, si se originaran domésticamente, o globales, si tuvieran su origen en las economías más desarrolladas y se transmitieran al resto de las economías del mundo o si afectaran a la mayoría de los países por igual. En este sentido, el trabajo trata de examinar empíricamente las predicciones de los modelos intertemporales de ciclos económicos, así como tas conclusiones de Glick y Rogoff (1995), Obstfeld y Rogoff (1996) y Elliot y Fatás (1996), respecto de los efectos de los shocks de productividad. Por otra parte, se investiga la importancia de algunos shocks de demanda, como los que se generan por variaciones en los gastos reales del gobierno, tanto a nivel nacional (idiosincráticos), como internacional (globales). También se evalúa el efecto de los cambios en los términos de intercambio externos. Por último, el trabajo analiza la influencia de los cambios en las tasas de interés internacionales y trata de evaluar el rol de los cambios en los salarios respecto de los precios de los bienes de capital; y el efecto de los precios de los bienes no transables en relación con los transables (en el proceso de inversión y en el resultado de la cuenta corriente). Estos dos últimos impulsos tratan de enfocar los factores, del lado de la producción de la economía, que podrían afectar a las tasas de ahorro nacional y de inversión doméstica.

No description available.

Doctor en Ciencias Farmacéuticas / Los pacientes críticos tienen serios cambios farmacocinéticos debido a situaciones fisiopatológicas relacionadas con su condición y por intervenciones para controlar el daño inicial. La filtración de grandes volúmenes de sangre a gran velocidad (Hemofiltración de Alto Volumen, HFAV), ha mostrado beneficios hemodinámicos en los pacientes severamente enfermos. Sin embargo, aún es incierta la dosificación de antimicrobianos durante su empleo, en especial para vancomicina, glicopéptido ampliamente utilizado en las Unidades de Cuidados Intensivos (UCI). El objetivo de este estudio fue describir la farmacocinética individual y poblacional de vancomicina en pacientes críticamente enfermos con shock séptico refractario recibiendo HFAV y definir una dosificación apropiada para estos pacientes según diferentes simulaciones de dosis. Método: Estudio farmacocinético prospectivo en la UCI del Hospital Clínico de la Universidad Católica, durante julio de 2011 a julio de 2012. Se extrajeron muestras de sangre y de líquido ultrafiltrado durante 12 horas de HFAV. Las muestras fueron analizadas por una metodología especialmente desarrollada en cromatografía líquida acoplada a espectrometría de masas. Se realizó un análisis de modelado no lineal de efectos mixtos para describir la farmacocinética poblacional. Finalmente, se realizó una simulación de dosis para vancomicina en diferentes condiciones de HFAV. Resultados: Se reclutaron 9 pacientes, de los cuales 5 eran hombres. El promedio de peso e índice SOFA fue 70±18 Kg y 11,3±3,9, respectivamente. Los valores promedio de la HFAV fueron un Qb cercano a 240 mL/min y una velocidad de ultrafiltración cercana a los 100 mL/Kg/h. El análisis farmacocinético poblacional indicó que vancomicina se ajusta a un modelo de dos compartimentos, con velocidad de administración de orden cero. Los parámetros farmacocinéticos estimados fueron clearance (CL) de 2,9 L/h, volumen de distribución del compartimento central (V1) de 11,8L, volumen de distribución del compartimento periférico (V2)de 18,0L y clearance intercompartimental (Q) de 9,3 L/h, muy similares a los parámetros descritos para pacientes sin deterioro de la función renal. La velocidad de HFAV resultó estar fuertemente asociada con el CL de vancomicina (p<0,05) y fue definido como la única covariable del modelo farmacocinético. Las simulaciones de dosis indicaron que luego de la administración de una dosis de carga, las dosis de mantención según las velocidad de HFAV deberían ser 750 mg cada 12 horas para HFAV= 69 mL/kg/h, 1000mg cada 12 horas para HFAV=100 mL/kg/h y 1500mg cada 12 horas para HFAV=123 mL/kg/h. La infusión continua también podría ser una estrategia válida de administración. En conclusión, se requieren dosis de vancomicina variables y mayores a las estándares para alcanzar concentraciones terapéuticas en pacientes durante HFAV / Critically ill patients have serious pharmacokinetic changes due to pathophysiological situations related to their condition and by interventions to control the initial injury. The filtration of large volumes of blood at high speed (High Volume Hemofiltration, HVHF) has shown benefits in severely ill patients. However, it is still uncertain dosing of antimicrobials during the procedure, especially for vancomycin, glycopeptide widely used in intensive care units (ICU). This study aimed to describe the individual and population pharmacokinetics of vancomycin in critically ill patients with refractory septic shock undergoing continuous venovenous HVHF and to define appropriate dosing for these patients according to several dose simulations. Method: This was a prospective pharmacokinetic study in theICU of the Universidad Católica Clinical hospital during July 2011 to July 2012. Blood and ultrafiltrate samples were taken over one vancomycin dosing interval during 12 hours of HVHF. Samples were analysed by a developed and validated liquid chromatography–tandem mass spectrometry assay. Non-linear mixed-effects modelling was used to describe the population pharmacokinetics. Dosing simulations were used to define therapeutic vancomycin doses for different HVHF settings. Results: Nine patients were included (five male). The mean weight and SOFA score was 70 kg and 11, respectively. Mean HVHF settings were: blood flow rate, 240 mL/min; and haemofiltration exchange rate, 100 mL/kg/h. A linear two-compartment model with zero-order input adequately described the data. Mean parameter estimates were: clearance (CL),2.9 L/h; volume of distribution of central compartment (V1), 11.8 L; volume of distribution of peripheral compartment (V2), 18.0 L; and intercompartmental clearance (Q), 9.3 L/h, all of them very similar to patients with normal renal function. HVHF intensity was strongly associated with vancomycin clearance (p<0.05) and was the covariate in the final pharmacokinetic model. Simulations indicate that after a loading dose, vancomycin doses required for different HVHF intensities would be 750mgevery12 h (q12 h) for 69 mL/kg/h, 1000mg q12 h for 100 mL/kg/h and 1500mg q12 h for 123 mL/kg/h. Continuous infusion would also be a valuable administration strategy. In conclusion, variable and much higher than standard vancomycin doses are required to achieve therapeutic concentrations during different HVHF settings / Conicyt

No description available.

The attenuation mechanism of shock waves of arbitrary strength propagating in air has been reasonably well understood. On the other hand, very little is known about the precise mechanism of shock wave attenuation and energy dissipation in liquids. The equation of state for shock propagation in water is empirical in nature and considerable differences exist with reference to the exact value of various constants even in the cast of Tait’ s equation of state, which is popularly used by researchers to describe the shock wave propagating through water. In recent times, considerable attention is being focused by researchers on shock wave attenuation and associated features in liquid medium mainly in the backdrop of development of many innovative industrial applications of shock waves. The present study focuses on generating reliable experimental data on shock wave attenuation in liquids of different viscosity. Experiments have been performed in a conventional vertical shock tube and a modified diaphragmless shock tube to understand how shock wave of requisite strength attenuates in liquids. A new vertical shock tube was designed, fabricated and successfully tested in the laboratory as a part of this study. In this new facility shock loading experiments with liquids or any complex fluid medium can be carried out. In the present study five liquids (Water, Castor Oil, Sodium Chloride (10%NaCl aqueous solution), Kerosene and Glycerin) have been subjected to shock wave loading. Exhaustive static pressure measurements in the liquid medium have been carried out to understand the attenuation characteristics of shock waves. The validity of Taits equation state has been experimentally verified for water. Based on the experimental results modified Taits equation of state has been obtained for castor oil, sodium chloride, kerosene and glycerin. Illustrative theoretical study is also carried out to complement the experiments.

The preionization of a shock tube's gas before the shock passes through it is called the precursor effect. An experimental and theoretical study has been carried out on precursor ionization in an electromagnetic shock tube. The precursor ionization was detected with different types of electric probes and also with photoraaltipliers. Extensive experiments indicated that the ionization was not due to diffusion of particles from the discharge in the shock tube driver. The ionization is primarily caused by radiation from the discharge of wavelengths less than 2000 Å. Radiation from the shock front makes a negligible contribution to the ionization. Langmuir double probe measurements indicated that the gas was about 0.1% ionized and that the electrons in the precursor were not in thermal equilibrium with the gas atoms and ions. The time interval between detection of ionization at two stations was independent of the shock tube gas (air, argon, helium), and corresponded to a propagation speed greater than 1/20 the speed of light. The precursor had a main component lasting about 50 microseconds with ionization proportional to the square of the discharge current. There was also a weaker component which lasted for about 500 microseconds. The experimental results can be understood in terms of a theoretical model based on black body radiation. Considering the driver to act as an infinite slab radiator, whose temperature is a function of the discharge parameters, an expression is derived for the number of photons emitted in some frequency interval. Assuming the electron density to be proportional to radiation absorption from such a radiator, the electron density variation with distance from the driver can be adequately understood. When the shock tube is considered to behave as a transmission line, whose resistance per unit length is proportional to the electron density, one can explain the variation of the shock tube's gas potential both with distance from the driver and with time. / Science, Faculty of / Physics and Astronomy, Department of / Graduate