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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

The Effects of Cyp2e1 on Hepatic Gene Expression in 129/Sv-Cyp2e1^tm1Gonz/J and 129S1/SvImJ Mice Exposed to Hydrazine

Lindgren, Kristjon, Seng, Dana January 2007 (has links)
Class of 2007 Abstract / Objectives: To characterize the difference in hepatic gene expression between Cyp2e1 +/+ and Cyp2e1 -/- mice after exposure to hydrazine in order to elucidate the functional pathway(s) for hydrazine-induced steatosis. Methods: The project was designed by Dr. Charlene McQueen and consisted of the following aims: (1) to characterize the hepatic pathology induced by hydrazine in CYP2E1 +/+ and -/- mice, (2) to evaluate hepatic gene expression profiles following exposure to hydrazine, and (3) to determine the expression of CYP2E1 and CYP4A14. The animal exposure and data collection have been completed and aim #2 is awaiting data analysis. Aim #2 consisted of treating CYP2E1 +/+ and CYP2E1 -/- mice to saline and hydrazine at doses of 100 mg/kg. Livers were collected at six and 24 hours and the mRNA was isolated with an Absolutely RNA RT-PCR Miniprep Kit. The transcriptome was determined using the Affymetrix GeneChip Expression Analysis System using total mouse genome GeneChips. The GeneChips were scanned using an Agilent GeneArray Scanner and the image was quantitated and archived awaiting data analysis. The data was collected by the SWEHSC Microarray Facility on June 20, 2005 was analyzed. The data analysis was completed by both Kristjon Lindgren and Dana Seng with the help and training from Dr. George Watts. The six sets of data from aim #2 was analyzed using Agilent's GeneSpring 7.3.1 software to characterize the two-fold differences in mice (n = 2 per group) hepatic gene expression. Genes of interest were identified as containing the keywords cyp, fatty, glutathione, hepat, lipid, liver, oxid, perox, steroid, and phosphatidylinositol in the Gene Ontology Biological Process, Cellular Component, or Molecular Function descriptions. Lastly, pathway mining of/for genes of interest was performed using Bioresource for array of genes (BioRag) available at www.biorag.org and maintained by the AzCC/SWEHSC Bioinformatics Facility. Results: The amount of information extracted from this research project is too immense to be described or summarized on this form. For more information, please obtain a copy of this research project from the University of Arizona College of Pharmacy or from the project co-authors Kristjon Lindgren (kristjon.lindgren@gmail.com) or Dana Seng (dana.seng@gmail.com). Conclusions: The effects of Cyp2e1 on hepatic gene expression in 129/Sv-Cyp2e1tm1Gonz/J and 129S1/SvImJ mice exposed to hydrazine was analyzed. Data showing that Cyp2e1 was protective against HD-induced hepatotoxicity was consistent with the proposed hypothesis. Hepatic gene expression results show that Cyp2e1 -/- mice have decreased expression of microsomal ω-oxidation genes (Cyp4a10 and Cyp4a14) compared to Cyp2e1 +/+ at 6h (both increased at 24h) and peroxisomal β–oxidation genes (Ehhadh) at 6h like Cyp2e1 +/+ (but increased at 24h only in Cyp2e1 -/-). Conversely, an increased expression of mitochondrial β-oxidation genes (Cpt1a) in both genotypes at 6 and 24h and cholesterol synthesis genes (Fdft1, Hmgcr, Hmgcs1, Idi, Lss, Mvk, Nsdhl, Sc4mol, and Sqle) in Cyp2e1 -/- at 24h was observed. These results support mechanisms by which ω-oxidation or PPARγ is protective or peroxisomal β- oxidation is damaging. Additional studies are needed to further eludidate the mechanisms of HD-induced steatosis.
142

Emergence of magnetic order in the Rare Earth Intermetallic PrPtAl

Abdul-Jabbar, Gino Jamal January 2014 (has links)
Magnetism of the rare earth intermetallics present some of the most important challenges for understanding correlated electron systems . In this thesis I distil this immense challenge, to understanding the unusual magnetic properties of the rare earth intermetallic PrPtAl. At first glance, PrPtAl appears to be a typical local f moment system, where the electronic states of Pr3+ are composed of nine singlet states, split by the crystal electric field for the J = 4 spin-orbit state in low crystal symmetry (orthorhombic, Pnma). The absence of a magnetic ground state would naively lead us to expect PrPtAl to be a simple paramagnet, but the results from this thesis show that the material is more complex, ordering magnetically at 5.7 K in spite of its singlet ground state. This thesis investigates the emergence of magnetic order in PrPtAl. For this purpose, the properties of PrPtAl were measured using high quality single crystals grown using the Czochralski technique. These crystals were used to measure: bulk properties at the Centre for Science at Extreme Conditions (CSEC, University of Edinburgh) and to perform neutron and x-ray magnetic scattering experiments at central facilities within Europe (ISIS, ESRF) and North America (NCNR). The results of this thesis conclusively show that PrPtAl does not directly realise ferromagnetism, but initially orders into two modulated magnetic states between 5.7-5.2 K and 5.2-4.7 K. These states cannot be explained using a simple local moment picture, but appear to be driven by a complex interaction between local moments and conduction electrons, in a possible quantum order-by-disorder type mechanism.
143

Novel cell surface markers identify routes to iPS cells

O'Malley, James January 2014 (has links)
The generation of induced pluripotent stem cells (iPSCs) presents a challenge to normal developmental processes. The low efficiency and heterogeneity of most methods have hindered understanding of the precise molecular mechanisms promoting, and roadblocks preventing, efficient reprogramming. While several intermediate populations have been described, it has proved difficult to characterize the rare, asynchronous transition from these intermediate stages to iPSCs. The rapid expansion of a minor population of reprogrammed cells can also obscure investigation of relevant processes. Understanding of the biological mechanisms essential for successful iPSC generation requires both accurate capture of cells undergoing the reprogramming process and identification of the associated global gene expression changes. Here we demonstrate that reprogramming follows an orderly sequence of stage transitions marked by changes in cell surface markers CD44 and ICAM1, and a Nanog-GFP reporter. RNA-sequencing (RNA-seq) analysis of these populations demonstrates two waves of pluripotency gene up-regulation, and unexpectedly, transient up-regulation of multiple epidermis-related genes, demonstrating that reprogramming is not simply the reversal of normal developmental processes. This novel high-resolution analysis enables the construction of a detailed reprogramming route map, and this improved understanding of the reprogramming process will lead to novel reprogramming strategies.
144

Micro- to Macro-Scale Structural and Lithological Architecture of Basal Nonconformities: Implications for Fluid Flow and Injection Induced Seismicity

Hesseltine, Garth 01 May 2019 (has links)
Rising incidents of earthquakes caused by human activity in the United States, known as induced earthquakes, is a growing concern. Induced earthquakes may occur when fluid and/or wastewater is injected several kilometers beneath the Earth’s surface into sedimentary rocks. Fluids and pressures can migrate from the sedimentary rocks, which are typically friendlier to fluid flow, into underlying less friendlier crystalline rocks along fluid pathways weakening and possibly reactivating preexisting faults. Understanding potential fluid pathways and/or barriers from the sedimentary rocks to crystalline rocks is crucial. I investigate the structure, composition, and heterogeneity of rocks near the contact between the sedimentary and crystalline rocks, known as nonconformities, and highlight their possible role in the transmission of fluids and porefluid pressures into the crystalline basement. To characterize nonconformities, we examined outcrop analogs and drillcore of nonconformities in New Mexico, Colorado, and Michigan. Geochemical, structural, and hydrological techniques were used to analyze the nonconformities at microscopic to megascopic scales. The nonconformities observed in this study consist of variably deformed, weathered, and altered igneous and metamorphic crystalline basement overlain by sedimentary rocks cut by outcrop- and map-scale faults. The nonconformity at the New Mexico sites includes a clay-rich weathered horizon atop deformed and jointed crystalline basement. Heterogeneity observed in the fracture and joint networks within the crystalline basement contributes to permeability heterogeneity and anisotropy. The crystalline basement adjacent to the nonconformity at the Colorado site is relatively fresh and unweathered and overlain by low permeability sandstones. The nonconformity and underlying slates in the Michigan drillcore are overprinted by hydrothermal alteration and carbonate mineralization, which provides evidence of hydrological communication between sedimentary and crystalline rocks. The nonconformities display a range of structural, hydrological, and geochemical styles and characteristics which vary over relatively small spatial extents. The geological and hydrogeological histories and complexities of nonconformity analogs provide valuable information to understand how fluids, past, and present, interact with the contact. This study introduces some of the factors that may control fluid flow adjacent to nonconformities and their possible significance to the interplay of deformation, fluid flow, and induced seismicity.
145

Misoprostol for the induction of labour at term.

Dodd, Jodie Michele January 2005 (has links)
Background: The aims of this randomised, double blind, placebo controlled trial were to compare vaginal PGE2 gel with oral misoprostol in the induction of labour at term. Methods: Women randomised to the oral misoprostol group received 20mcg oral misoprostol solution at two hourly intervals and placebo vaginal gel, and those in the vaginal prostaglandin group received vaginal PGE2 gel at six hourly intervals and oral placebo solution. The primary outcome measures were vaginal birth not achieved in 24 hours, uterine hyperstimulation with associated fetal heart rate changes, and caesarean section. Women were asked about their preferences for care, and a cost comparison was performed for the two methods of induction of labour. A nested randomised trial compared health outcomes for the woman and her infant related to morning or evening admission for commencing induction of labour. Results: A total of 741 women were randomised, 365 to the misoprostol group and 376 to the vaginal PGE2 group. There were no differences between women in the oral misoprostol group and women in the vaginal PGE2 group, for the outcomes vaginal birth not achieved in 24 hours (Misoprostol 168/365 (46.0%) versus PGE2 155/376 (41.2%); RR 1.12 95% CI 0.95-1.32; p=0.134), caesarean section (Misoprostol 83/365 (22.7%) versus PGE2 100/376 (26.6%); RR 0.82 95% CI 0.64- 1.06; p=0.127), or uterine hyperstimulation with fetal heart rate changes (Misoprostol 3/365 (0.8%) versus PGE2 6/376 1.6%); RR 0.55 95% CI 0.14-2.21; p=0.401). Women in the misoprostol group were more likely to indicate that they 'liked everything' associated with their labour and birth experience compared with women in the vaginal PGE2 group (Misoprostol 126/362 (34.8%) versus PGE2 103/373 (27.6%); RR 1.26; 95% CI 1.02-1.57; p=0.036). There were no differences in the primary outcomes when considering morning or evening admission to commence induction. The use of misoprostol was associated with a saving of $110.83 per woman induced. Conclusions: The use of oral misoprostol in induction of labour does not lead to poorer health outcomes for women or their infants, women express greater satisfaction with their labour and birth experience, and with misoprostol induction there is a cost saving to the institution. / Thesis (Ph.D.)--Department of Obstetrics and Gynaecology, 2005.
146

Kvinnors upplevelser i samband med abort

Bäcklund, Anna, Nilsson, Linda January 2007 (has links)
<p>The treatment that women get from health care staff can influence the experience of the abortion and how women manage to coping the experience emotionally. The aim of this study was to illuminate women’s experiences in connection with an abortion. The findings show that the women’s social situation led them to the decision of abortion. When the women had the pregnancy confirmed many felt unreality. Several women experienced the situation as a crisis. After the abortion most of the women experienced relief, but also guilt towards the abortion. Some knew that they had made the right decision, while others felt regret. Most of the women experienced that the nursing staff treated them well, but some women experienced that the staff was negative, insensitive and ignoring. Most of the women was satisfied with the total support from significant others. To make a satisfying nursing care possible for each woman who seeks abortion, more research is needed about women’s experiences of nursing staff’s treatment.</p>
147

Qualitative Depth and Shape from Stereo, in Agreement with Psychophysical Evidendence

Weinshall, Daphna 01 December 1987 (has links)
Obtaining exact depth from binocular disparities is hard if camera calibration is needed. We will show that qualitative depth information can be obtained from stereo disparities with almost no computations and with no prior knowledge (or computation) of camera parameters. We derive two expressions that order all matched points in the images in two distinct depth-consistent ways from image coordinates only. One is a tilt-related order $\\lambda$, the other is a depth-related order $\\chi$. Using $\\lambda$ demonstrates some anomalies and unusual characteristics that have been observed in psychophysical experiments. The same approach is applied to qualitatively estimate changes in the curvature of a contour on the surface of an object, with either $x$- or $y$-coordinate fixed.
148

Effect of ausforming via severe plastic deformation on shape memory behavior of NiTi

Kulkarni, Ajay V. 12 April 2006 (has links)
In this study, Thermomechanical properties of Ti-50.8 and 50.7 at% Ni alloy severely deformed using Equal Channel Angular Extrusion (ECAE) are investigated. The aim of this study is to reveal the effects of severe plastic deformation on shape memory, pseudelasticity, interplay between plastic deformation via dislocation slip and twinning, and forward and reverse martensitic transformation. The samples are processed at room temperature, i.e. slightly above the austenite finish temperature, and at 450 °C, i.e. well-above the austenite finish temperature. Transformation temperatures, microstructural evolution, and thermomechanical properties of ECAE processed samples are studied before and after low temperature annealing heat treatment and compared with conventional cold drawn and precipitation hardened material. The unique findings are: 1) the observation of a mixture of heavily deformed B2 (austenite) and B19’ (martensite) phases in the samples processed at room temperature although martensite stabilization was expected, 2) the observation of highly organized, twin-related nanograins in B2 phase of the samples deformed at room temperature which was attributed to B2 to B19' via SIM, and B19' to B2 via SPD (SIM: Stress Induced Martensitic transformation, SPD: Severe Plastic Deformation) transformation sequence, 3) simultaneous observation of B2 austenite and strain induced B19’ martensite in the samples deformed at 450 °C, and 4) perfect pseudoelasticity, small pseudoelastic stress hysteresis and excellent cyclic response with no irrecoverable strain up to 1000 cycles for ECAE at 450 °C processed sample. Strain induced martensite in NiTi alloys was reported for the first time. The formation of well-organized twin-related nanograins via severe plastic deformation opens a new opportunity for twinning induced grain boundary engineering in NiTi alloys which significantly improves the matrix strength and the cyclic response against degradation of shape memory and pseudoelasticity.
149

Strain gradient based analysis of transformation induced plasticity in multiphase steels

Mazzoni, Louise 26 February 2010 (has links)
<p align='justify'>This thesis is devoted to the micromechanical study of the size-dependent strengthening in Transformation Induced Plasticity (TRIP) steels. Such grades of advanced high-strength steels are compelling for the automotive industry, due to their improved mechanical properties. Among others, they combine a good strength versus ductility balance. In this context, many research works have been carried out to study these grades of steels. In particular, from a numerical point of view, earlier studies within the framework of classical plasticity do not properly reproduce the strengthening levels characterizing TRIP steels and obtained experimentally.</p> <p align='justify'>In this study, the strain gradient plasticity theory presented by Fleck and Hutchinson (2001) is chosen to account for the strengthening effect resulting from the phase transformation. A two-dimensional embedded cell model of a simplified microstructure composed of small cylindrical metastable austenitic inclusions, partially undergoing the phase transformation, within a ferritic matrix is used.</p> <p align='justify'>First, the single-parameter version of the strain gradient plasticity theory under small strain assumption is used for the simulations. The impact of the higher order boundary conditions is assessed. It is shown that, when the plastic flow is unconstrained at the elasto-plastic boundaries, the transformation strain has no significant impact on the overall strengthening. The strengthening is essentially coming from the composite effect with a marked inclusion size effect resulting from the appearance during deformation of new boundaries (at the interface between parent and product phases) constraining the plastic flow.</p> <p align='justify'>Second, the multi-parameter version of the strain gradient plasticity theory, incorporating separately the rotational and extensional gradients in the formulation, is employed under small strain assumption. The effect of the plastic strain gradients resulting from the transformation strain is better captured. In particular, the results show a significant influence of the shear component of the transformation strain. An implicit confinement effect is revealed at the elasto-plastic boundaries which is partly responsible for the transformation strain effect. Size effects on the overall strengthening are also revealed, due to a combined size dependent effect of the transformation strain and of the evolving composite structure.</p><p align='justify'>Third, the extension of the strain gradient plasticity theory to a finite strain description is applied. A significant effect of the transformation strain is obtained with the multi-parameter version of the theory as well as an optimal austenite grain size improving the damage resistance of the martensite, in agreement with the typical grain size of the current TRIP-assisted steels (Jacques et al., 2007).</p>
150

Kvinnors upplevelser i samband med abort

Bäcklund, Anna, Nilsson, Linda January 2007 (has links)
The treatment that women get from health care staff can influence the experience of the abortion and how women manage to coping the experience emotionally. The aim of this study was to illuminate women’s experiences in connection with an abortion. The findings show that the women’s social situation led them to the decision of abortion. When the women had the pregnancy confirmed many felt unreality. Several women experienced the situation as a crisis. After the abortion most of the women experienced relief, but also guilt towards the abortion. Some knew that they had made the right decision, while others felt regret. Most of the women experienced that the nursing staff treated them well, but some women experienced that the staff was negative, insensitive and ignoring. Most of the women was satisfied with the total support from significant others. To make a satisfying nursing care possible for each woman who seeks abortion, more research is needed about women’s experiences of nursing staff’s treatment.

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