MARKET STRUCTURE AND MORTGAGE PRICING: THE ROLE OF INFORMATION IN FIRM AND CONSUMER BEHAVIOR

This dissertation analyzes information, market structure, and firm pricing strate-gies. I begin the dissertation with an analysis of the market structure of the mortgage in-dustry. I find that the configuration of the mortgage market at its present state is vastly different than its historical structure. The reduction in the cost of transmitting informa-tion has increased the collaborative environment and facilitated the dis-integration of the supply chain. Generally, the mortgage industry has been successful at reducing principal-agent problems and minimizing asymmetric information concerns that arise in segmented markets. In the first essay I provide a theoretical explanation of the effect of the internet on market outcomes. Search models assume that the reduction in search frictions would lead to competitive markets. However, I argue that gatekeepers operating in online markets may create an anticompetitive effect, in addition to reducing the consumers’ search cost. Therefore, the conduct of the gatekeeper can cause prices in online markets to be higher than in retail markets and provide online firms with larger profits. In the second essay “I empirically examine the role of the internet and Internet Comparison Search sites in reducing consumer search costs and their effects on the prices consumers pay for mortgages. Additionally, I expand the study to test for the effects of the internet on firm profits. Using a unique data set, I examine a mortgage firm’s pricing strategies and profits in online and retail markets, and find evidence of market power in online markets that do not exist in retail markets. The presumed benefits to the consumer from the reduction of search cost are offset by the anticompetitive environment in online markets. In the final essay, I examine a mortgage firm’s portfolio choice. I investigate the loan characteristics that affect the firm’s decision to retain mortgages as part of its own portfolio. I find that the decision to retain loans as a lender is driven by unobservable qualities. The firm does sort loans by quality, but it also prices non-brokered loans lower based on unobservable qualities. The sorting behavior suggests that asymmetric information exists between the lender and the secondary market

Investigation of the constancy of the MWCNTs on the fibres surface for manufactured self-sensing composites

This the author accepted manuscript. The fial version is available from Elsevier via the DOI in this recordDifferent methods have been used to deposit the multi-walled carbon nanotubes (MWCNTs) onto the fibre surface to fabricate self-sensing composites. However, the constancy of the MWCNTs onto the fibre surfaces during infusion processing still unclear. In this study, we have deposited MWCNTs onto the glass fibre surface by two methods to investigate the state of MWCNTs during and after epoxy infusion processing. In the first method, the glass fibres were directly coated with the MWCNTs and in the second method, an adhesive was applied to coat the glass fibre surface before depositing the MWCNTs over it. Rectangular specimens for both types of self-sensing composites were cut from different specified zones and then tested. The results showed that the self-sensing composites with adhesively bonded MWCNTs exhibited more consistent in their properties than the composites where no adhesive was used. In addition, the electrical resistance of both types of self-sensing composites was monitored during the epoxy infusion process. The results showed that the electrical resistance was not obviously affected for composite with non-adhesive bonded MWCNTs and was high for the specimens where the MWCNTs were not adhesively bonded. Moreover, the numerical study was also conducted and the results indicated that the relationship between the volume fraction of the MWCNTs and their tunnelling distance was an inverse. The current study proves evidence that the properties of the self-sensing composites are strongly dependent on the method that used to deposit the MWCNTs on the surface of glass fibres layers.Iraqi Ministry of Oi

A novel simultaneous quantification method for fat-soluble vitamins using liquid chromatography-tandem mass spectrometry for clinical applications

The accurate and precise quantification of fat-soluble vitamins (FSVs), specifically vitamins A, D and E, has proved to be a challenge for clinical laboratories. This challenge is partially the result of the nature of FSV molecules and the limitations in techniques commonly used in their analysis. Consequently, there is a variation in the results obtained through different techniques or by different clinical laboratories. As a result, it has been difficult to reach agreement on the recommended levels or reference intervals of these vitamins. The current project encompassed the development of a state-of-the-art analytical method for the analysis of vitamins A (retinol), D (25-hydroxyvitamin D [25-OHD]) and E (α-tocopherol) in blood using liquid chromatography-tandem mass spectrometry (LC-MS/MS), which is a highly sensitive and specific quantification technique. Four studies were then performed to explore several scientific knowledge gaps related to vitamin measurement using the developed FSV quantification methods. The Current translational clinical research introduced novel and precise simultaneous measurement methods for blood FSV analytes, which were applicability to clinical sampling trials. This thesis also provides the first study exploring the stability FSVs simultaneously in routine sample spectrum utilising a precise LC-MS/MS method. In addition, stability of each analytes is justified based on calculation of the acceptable clinical limits, which reflect biological variation as well as method imprecision. This project also highlighted problematic issue related to trueness and reliable traceability of commercial calibrators to high order references and that interrupts effort of method harmonisation and patient result comparability. Furthermore, the current thesis provides with first study validated the measurement of 25-OHD3 and retinol in UCB diluted plasma. Lastly, this thesis reports the first study exploring status of five FSV analytes in two Australian populations at different latitudes using simultaneous measurement LC-MS/MS method. Furthermore, this is the first work examined the correlation between the blood FSV levels in two Australian populations

The fabrication and testing of a self-sensing MWCNT nanocomposite sensor for oil leak detection

Abstract Oil spillage, due to either direct or indirect accidents, can cause major environmental and economic issues if not detected and remedied immediately. In this study, the unique properties of carbon nanotubes have shown a substantial sensing capability for such a purpose when incorporated into a nanostructured composite material. A high-efficiency self-sensing nanocomposite sensor was fabricated by inserting highly conductive multi-walled carbon nanotubes (MWCNTs) into an elastomeric polymer substrate. The microstructure of the nanocomposite sensor was studied using scanning electronic microscopy and Raman spectroscopy. The response rate of the sensor was evaluated against different MWCNT concentrations, geometrical thickness and applied strains (causing by stretching). The results indicated that the response rate of the sensor (β) decreased with increasing MWCNT concentration and showed the strongest response when the sensor contained a 1.0 wt % concentration of MWCNTs. Additionally, it was found that the response time of the self-sensing nanocomposite sensors decreased in keeping with decreases in the sensor thickness. Moreover, when the sensor was subjected to strain, while immersed in an oil bath, it was found that the response rate (β) of the unstretched self-sensing nanocomposite sensor was significantly lower than that of the stretched one. The sensors given a 3% applied strain presented a response rate (β) ≈ 7.91 times higher than of the unstretched one. The self-sensing nanocomposite sensor described here shows good potential to be employed for oil leakage detection purposes due to its effective self-damage sensing capability and high sensing efficiency and low power consumption.</jats:p

Transmorphic phage-guided systemic delivery of TNFα gene for the treatment of human pediatric medulloblastoma

Medulloblastoma is the most common childhood brain tumor with an unfavorable prognosis and limited options of harmful treatments that are associated with devastating long-term side effects. Therefore, the development of safe, noninvasive, and effective therapeutic approaches is required to save the quality of life of young medulloblastoma survivors. We postulated that therapeutic targeting is a solution. Thus, we used a recently designed tumor-targeted bacteriophage (phage)-derived particle, named transmorphic phage/AAV, TPA, to deliver a transgene expressing the tumor necrosis factor-alpha (TNFα) for targeted systemic therapy of medulloblastoma. This vector was engineered to display the double-cyclic RGD4C ligand to selectively target tumors after intravenous administration. Furthermore, the lack of native phage tropism in mammalian cells warrants safe and selective systemic delivery to the tumor microenvironment. In vitro RGD4C.TPA.TNFα treatment of human medulloblastoma cells generated efficient and selective TNFα expression, subsequently triggering cell death. Combination with the chemotherapeutic drug cisplatin used clinically against medulloblastoma resulted in augmented effect through the enhancement of TNFα gene expression. Systemic administration of RGD4C.TPA.TNFα to mice-bearing subcutaneous medulloblastoma xenografts resulted in selective tumor homing of these particles and consequently, targeted tumor expression of TNFα, apoptosis, and destruction of the tumor vasculature. Thus, our RGD4C.TPA.TNFα particle provides selective and efficient systemic delivery of TNFα to medulloblastoma, yielding a potential TNFα anti-medulloblastoma therapy while sparing healthy tissues from the systemic toxicity of this cytokine

Damage sensing and mechanical properties of a laminate composite material containing MWCNTs during low-velocity impact

In this work, we present a new criterion, unlike other attempts, to evaluate and quantify the degree of damage of composite material when it subjected to a sudden impact load. Our criterion exploits the high intrinsic electrical conductivity property of the Multi-walled carbon nanotubes (MWCNTs) after dispersing different concentrations of them (0, 0.5, 1.0, 1.5 and 2.0 %) in the epoxy matrix of a glass fibre composite. Following this goal, the low-velocity impact and flexural after impact (FAI) tests on the MWCNTs-glass epoxy (i.e. MWCNTs-GF) nanocomposite were evaluated. At the same time, the changes in its electrical resistance were measured. The results showed that the properties of the self-sensing composites were significantly affected by impact energy. The damage after impact causes an increase in the electrical resistance of the MWCNTs-GF nanocomposite and increases with increased impact energy. In addition, the samples containing a high concentration of MWCNTs showed lower damage sensitivity under all impact energies levels as compared with the samples contain a lower MWCNTs concentration. Therefore, the results presented in this work have shown that it is possible to associate the change in electrical resistance of the MWCNTs-GF nanocomposite with the degree of damages caused by impact load.</jats:p

White Matter Hyperintensity Regression: Comparison of Brain Atrophy and Cognitive Profiles with Progression and Stable Groups

Subcortical white matter hyperintensities (WMHs) in the aging population frequently represent vascular injury that may lead to cognitive impairment. WMH progression is well described, but the factors underlying WMH regression remain poorly understood. A sample of 351 participants from the Alzheimer’s Disease Neuroimaging Initiative 2 (ADNI2) was explored who had WMH volumetric quantification, structural brain measures, and cognitive measures (memory and executive function) at baseline and after approximately 2 years. Selected participants were categorized into three groups based on WMH change over time, including those that demonstrated regression (n = 96; 25.5%), stability (n = 72; 19.1%), and progression (n = 209; 55.4%). There were no significant differences in age, education, sex, or cognitive status between groups. Analysis of variance demonstrated significant differences in atrophy between the progression and both regression (p = 0.004) and stable groups (p = 0.012). Memory assessments improved over time in the regression and stable groups but declined in the progression group (p = 0.003; p = 0.018). WMH regression is associated with decreased brain atrophy and improvement in memory performance over two years compared to those with WMH progression, in whom memory and brain atrophy worsened. These data suggest that WMHs are dynamic and associated with changes in atrophy and cognition