An extant model was evaluated to assess its adequacy for nutrient management planning for swine operations in Manitoba with regards to phosphorus (P) and nitrogen (N) excretion and the land base for the optimum spreading of manure based on P requirement of crops. Two dietary treatments were used, control diet formulated to meet the requirement of pigs for nutrients as per the recommendations of NRC (No-phytase) and a diet formulated with P level in the No-phytase diet reduced by an average of 0.1 percentage units and amended with microbial phytase at 500 FTU/kg (Phytase). Data was generated from starter to finisher pigs (10 per dietary treatment) and sows (9 per dietary treatment) to evaluate the model. The model was found to be adequate for the prediction of P outputs from starter to finisher but not sows. Model was found to be inadequate for prediction of N output.

The mucosal antibody repertoire of the cervical mucosa in commercial sex workers from Nairobi, Kenya, who are highly sexually exposed to human immune deficiency virus type-1 (HIV-1) but remain persistently IgG seronegative (HEPS), may represent a novel source of broadly neutralizing monoclonal antibodies (mAbs) against HIV-1. Mucosal IgA specific for HIV-1 envelope (Env) subunit gp41 has been suggested as a correlate of protection in HEPS individuals. The in depth studies at both the gene and function level required to confirm their role in HIV-1 resistance are possible only using recombinant monoclonal IgAs. Human mAbs have traditionally been selected from libraries displayed on the surface of microorganisms (phage, yeast). However, due to inherent limitations, such techniques may not be optimal for isolating such rare mAbs from a pool of cervical B cells. We have developed an antibody selection system based on surface display on mammalian cells and used this technology to isolate four novel monoclonal antibodies, against linear epitopes on gp41, from the IgA repertoire of the cervical mucosa in Kenyan HEPS. Furthermore, three of the four mAbs were shown to bind with surface expressed consensus clade B and clade C Env on mammalian cells. Characterization of the variable region cDNA of the two strongest binding mAbs reveals extensive somatic mutations with a bias of replacement mutations clustering in the complementary determining regions (CDR) indicating antigen-driven affinity maturation had occurred. Affinity matured monoclonal IgAs, such as these, may play a role in the identification of new, vulnerable epitopes on HIV-1, or act as a component in a topical microbicide.

The present dissertation reports the findings of a study of cracking behavior of a newly developed superalloy, Allvac 718Plus during high power beam welding and post-weld heat treatment. Microstructures of the base alloy, heat affected zone (HAZ) and fusion zone (FZ) of welded and post-weld heat treated (PWHT) coupons were examined by the use of standard metallographic techniques involving optical microscopy, analytical scanning electron microscopy (SEM) and analytical transmission electron microscopy. Moreover, grain boundary segregation behavior of boron atoms during pre-weld heat treatments was evaluated using secondary ion mass spectroscopic system. In the first phase of the research, 718Plus was welded using a low and high heat input CO2 laser to assess its weld cracking response. Detailed examination of the welds by analytical electron microscopic technique revealed the occurrence of cracking in the HAZ of low heat input welds, while their FZ was crack free. However, both the FZ and HAZ of high heat input welds were crack-free. Resolidified constituents were observed along the cracked grain boundaries of the lower heat input welds, which indicated that HAZ cracking in this newly developed superalloy was associated with grain boundary liquation. However, despite a more extensive liquation of grain boundaries and grain interior in the HAZ of high heat input welds, no cracking occurred. This was attributed to the combination of lower welding stresses generated during cooling, and relaxation of these stresses by thick intergranular liquid. Although HAZ cracking was prevented by welding with a high heat input laser, it resulted in a significant damage to the parent microstructure through its extensive liquation. Thus, the use of low heat input welding is desirable. However, this resulted in HAZ cracking which needs to be minimized or eliminated. Therefore, during the second phase of this research, the effects of pre-weld thermal processing on the cracking response of 718Plus were investigated. Results from the quantification of the cracking of the alloy showed that HAZ cracking may be significantly reduced or eliminated through an adequate selection of pre-weld thermal cycle. In the third stage of this research, crack-free welds of 718Plus were post-weld heat treated using standard thermal schedules. A significant solid state cracking of the alloy occurred during the PWHT. The cracking was attributed to the presence of embrittling phases on HAZ grain boundaries, coupled with aging contraction stresses that are generated by a considerable precipitation of gamma prime phase during aging.

Contaminated environmental surfaces can be a means of transmission of Clostridium difficile spores in health-care facilities. The study objectives are to assess the value of the UV marker as an audit tool for improving housekeeping compliance and to compare microfiber and cotton cloths for removal of Clostridium difficile spores from surfaces. A lotion visible only under short-wave UV light (UV Marker) was applied to different surfaces within the patient’s washrooms on consecutive week days, over a twenty-four week period. The Study included three Arms: Arm one received feedback for 24 weeks , Arm two received feedback for the first 12 weeks and Arm three was given feedback for the last 12 weeks based on UV Marker results. The visual audit resulted in a cleaning compliance of 55%; whereas, feedback with the UV Marker led to a housekeeping compliance of 90%. The UV marker is a better audit tool than visual inspection for improving cleaning compliance of housekeeping staff. The use of microfiber cloths may enhance efficiency of microbial removal during surface cleaning.

The lymphatic vasculature is a network of unidirectional capillaries and ducts, which serve to return extracellular fluid and macromolecules to the systemic blood circulation. In addition, the lymphatic vessels have important roles in immune surveillance and fat absorption. Dysfunction of lymphatic vessels has profound physiological consequences. Insufficient lymph uptake results in lymphedema, a chronic disabling condition that currently has no cure. Lymphedemcanoccureither due to developmental defects (primary lymphedema) or due to injuries of existing lymphatic vessels (secondary lymphedema). The significance of lymphangiogenesis in tumour metastasis is demonstrated by the finding that increased lymphangiogenesis is associated with a higher rate of metastasis and poorer prognosis in cancer patients. Prox1, a homeoboxgene, regulates the development of the lymphatic vasculature by upregulating the expression of lymphatic endothelial markers and simultaneously repressing the expression of blood endothelial markers. To explore the mechanisms by which Prox1 establishes lymphatic cell fate, we compared Prox1 mediated activation oftwo key lymphatic cell surface receptors: theVascular Endothelial Growth Factor Receptor-3 (VEGFR-3) and theFibroblast Growth Factor Receptor-3 (FGFR-3) genes. Using a combination of luciferase gene reporter assays and immunoblotting, we compared the ability of different Prox1 constructs to activate either VEGFR-3 or FGFR-3 at both the mRNA and protein levels, respectively. Furthermore, we tested whether recombinant PROX1 protein was able to bind to the proximal promoter regions of VEGFR-3 and FGFR-3usingelectrophoretic mobility shift assays (EMSA). DNA binding deficient Prox1 versions did not activate the FGFR-3 promoter. In contrast, these versions of Prox1still efficiently activated transcription of the VEGFR-3 promoter. In agreement with our luciferase reporter gene assays, immunoblotting of HUVECs demonstrated that only infection with wt Prox1adenovirus increased expression of the FGFR-3 protein. Infection of HUVECs with adenoviral vectors encoding eitherwt Prox1orHDPD∆ Prox1was sufficient to induce a significant increase in VEGFR-3 protein levels. Surprisingly, our EMSA results with recombinant PROX1 demonstrated that PROX1 can bind to the promoter region of both VEGFR-3 and FGFR-3 genes via its DNA binding domain. We showed that PROX1 potentially binds to the promoter region of the VEGFR-3 gene via a consensus Prospero binding site (CGCCTCGGC). Our data demonstrates that, in endothelial cells, PROX1 utilizes distinct mechanisms to activate these two key endothelial growth factor receptors.

This thesis focuses on the high strain rate behavior of Maraging steel 300, High Hardness Armor (HHA) and Aluminum 5083 – H131 Alloy. These materials are used by the Department of National Defense (DND) of Canada as armor plate materials in military applications. The aim of the research is to investigate the dynamic shear-strain response of these armor materials at high strain rate loading to study the occurrence of Adiabatic Shear Bands and the subsequent failure. The effects of impact momentum and strain rates on the dynamic stress-strain curve and on the adiabatic shear failure of these armor materials under impact and torsion loading need to be investigated to evaluate their capability to withstand military conditions.

Catalase-peroxidases (KatGs), responsible for the activation of the anti-tubercular prodrug isoniazid (INH), are unusual members of the class I plant peroxidase family that possess strong catalase activity as well as peroxidase activity. Due to their strong catalase activity and their ability to activate INH, KatGs have been the subject of intense study for many years, and thus the goal of this work is to further characterize this enzyme in the hope of gaining a better understanding into these unusual reactions. Recent successful crystallization of a few representative KatGs revealed a unique covalent Met-Tyr-Trp cross-link joined to the conserved tryptophan in the heme active site, along with a nearby arginine that is in ionic association with the cross-linked tyrosine. Using the KatG from Burkholderia pseudomallei (BpKatG) as a model, site-directed mutagenesis to these residues revealed that they were essential for catalase, but not peroxidase activity. Structural and kinetic analysis revealed that Arg426 acts as a molecular switch, moving between 2 conformations, favoring heme oxidation when not in association with Tyr238 and favoring heme reduction when in association with Tyr238 by imparting its influence on the heme through the cross-link. Analysis of the reaction with peroxyacetic acid using stopped-flow spectrophotometry revealed an initial, rapidly formed enzyme-substrate complex before the formation of the oxoferryl compound I. Kinetic characterization revealed that formation of both the enzyme-substrate complex and the oxoferryl species were dependent on peroxyacetic acid concentration implying that 2 molecules of peroxyacetic acid are required to form the oxoferryl compound I intermediate. Successful co-crystallization with INH and its co-substrate, NAD+ has revealed their binding sites for the first time in a KatG. The NAD+ binding site is 20 Å from the entrance to the heme cavity, involving interactions primarily with the ADP portion of the molecule. The best defined INH binding site is located in a funnel shaped channel on the opposite side of the protein from the entrance channel that requires the movement of a glutamate residue for binding. The structures suggest that once INH is cleaved to the isonicotinoyl radical it diffuses to the NAD+ binding site to form the final active antimicrobial compound, IN-NAD, in a non-enzymatic reaction enhanced by the enzyme’s ability to bind NAD+.

Basically, my dissertation focuses on License Auctions. Four chapters of my dissertation are theoretical analysis of license auctions. Broadly speaking, I analyze the effects of different auction rules on revenue, efficiency and social welfare. The first chapter studies the flaw in the design of the 2000 Turkish GSM auction. In this auction, the Turkish government wants to raise as much revenue as possible and to increase competition in the cell-phone market by selling two licenses to new firms via a sequential auction, but it ends up with only one license sold. I identify this auction design failure. And I also show that if the auction were designed as a “simultaneous auction”, the government would sell two licenses and receive more revenue. In the second chapter, I show that if the cost asymmetry between the bidding firms is large enough, then having fewer firms in the market will surprisingly result in higher social welfare. This result is contrast to the common or general case in which “social welfare” will be higher if there are more firms competing in the market. In the third chapter, I characterize the optimal bidding strategies of local and global bidders for two heterogeneous licenses in a multi-unit simultaneous ascending auction with synergies. I determine the optimal bidding strategies in the presence of an exposure problem and show that global bidders may accept a loss even when they win all licenses and moreover, if a “bid-withdrawal” rule is introduced to the auction, the exposure problem disappears, and the simulation results show that revenue will be higher. In the last chapter, I study the Canadian AWS auction in which 40 percent spectrum are set aside for new firms. I characterize the effect of spectrum set-aside auctions on seller's revenue, consumer surplus and social welfare. I show that a spectrum set aside may not only encourage new entry and increase competition in the downstream market, but also under some circumstance, decreases the seller's revenue and consumer surplus. But a spectrum set aside results in inefficient allocation, and this inefficient entry further reduces social welfare.

Hyaluronan (HA) is a glycosaminoglycan that is abundant in the extracellular matrix of vertebrate cells. Under physiological conditions HA exists in a high-molecular-weight form, whereas HA fragments accumulate at sites of tissue injury and inflammation. Hyaluronidases are a group of enzymes that initiate the breakdown of HA. In humans, six hyaluronidase-like sequences have been identified in two locations, 3p21.3 (HYAL1, HYAL2 and HYAL3) and 7q31.3 (HYAL4, SPAM1 and HYALP1). Deficiency of one of these enzymes, HYAL1, was identified in a patient with Mucopolysaccharidosis IX, a disorder characterized by peri-articular soft masses containing HA-filled lysosomes. Given the broad distribution of HA and the mild phenotype of the patient, it is likely that other hyaluronidases or possibly the exoglycosidases, β-hexosaminidase and β-glucuronidase, are playing a major role in HA degradation. To address the potential role of HYAL3 in HA degradation in health and disease, a Hyal3-deficient mouse model was generated. Hyal3-deficient mice were viable, fertile and appeared to have no gross phenotype. The only difference observed was a subtle change in the cellularity and tissue structure of lungs from aged Hyal3-deficient mice. Further studies focused on analysis of HA homeostasis revealed a significant increase in HA in the airways of Hyal3-deficient lungs. Altered HA homeostasis is observed in rodent models of several lung conditions. In order to further study the role of Hyal3 in lungs, an ovalbumin-challenged inflammation model was generated in Hyal3-deficient mice. A significant increase in lung HA levels and altered distribution of HA in the airways of lungs was detected in ovalbumin-challenged Hyal3-deficient mice. Moreover, lung inflammation and airway resistance were increased in Hyal3-deficient mice after ovalbumin-challenge compared to similarly treated Hyal3-control mice. This suggests HA homeostasis that is altered during Hyal3-deficiency might be directly or indirectly promoting inflammation and airway resistance. Because the reported level of HA accumulation was very low in Hyal1-deficient and Hyal2-deficient mice, and in our studies of Hyal3-deficient mice, we performed preliminary studies to assess a role for an exoglycosidase, β-hexosaminidase, in HA turnover. Our preliminary studies indicate there is no or little HA accumulation in β-hexosaminidase-deficient mouse tissues. To conclude, our study of Hyal3- and β-hexosaminidase-deficient mice suggests that these are not the major enzymes involved in HA degradation

Using Northern Ireland this study seeks to establish what conditions on the ground must be cultivated in order for this ripe moment to come to pass. This thesis argued that five conditions in particular were necessary, though not necessarily sufficient, for the success of the Belfast Agreement. These five conditions (1) the inclusivity of the negotiation process, (2) efforts to foster positive cross community contact, (3) the positive involvement of external ethno-guarantors(EEGs), (4) the involvement of formal international primary mediators, and (5) the use of targeted economic aid. What emerged was that when taken together, these conditions created the pillars upon which a more stable agreement was reached. What is also important is that none of these conditions are short term investments; they all involved a long term commitment to peacebuilding that began long before the official negotiations of the BA.