Graduation date: 1995

This thesis is focused on the heparan sulphate (HS) structure from blind mole rat liver. HS is a glycosaminoglycan that is produced as a proteoglycan, in which linear polysaccharide chains are attached covalently to a protein core. Proteoglycans are widespread molecules in the body and have many important physiological functions. HS is synthesized as a polymer of alternating glucuronic acid and N-acetylglucosamine units. Parts of the polymer are subsequently modified by N-deacetylation /N-sulphation of the glucosamine units, C-5 epimerization of glucuronic acid to iduronic acid and O-sulphation at various positions. The mole rats are from Israel and are of the Spalax ehrenbergi superspecies. Spalax Judaei (S60) has 60 chromosomes and Spalax Galili (S52) has 52 chromosomes. They are both completely blind and spend their entire life underground in hypoxic conditions. Spalax Galili (S52) inhabits the cool-humid Upper Galilee Mountains and Spalax Judaei (S60) inhabits the warm-dry southern regions. There is no current information about the heparan sulphate structure of these animals. The two blind mole rats (S52 and S60) were metabolically labelled with [3H] Glucosamine. The animals were sacrificed and the organs were taken and frozen. The liver was chosen for the purpose of my project. The HS structure was studied using various chromatographic methods such as ion-exchange and gel filtration. Structural analysis of HS indicated that the size of HS from the liver was the same in both species. However, the domain structure differed between the two animals, particularly with regard to sample S52(1) which had obvious differences. This leads to the study of the heparanase cleavage sites. Disaccharide composition analysis identified varying proportions of disaccharide species in S52 and also the possibility of an unknown disaccharide species.

Surface mining of oil sands in northern Alberta requires stripping of saline-sodic shale overburden, which is typically placed in large upland overburden dumps. Due to the chemical nature of this shale, engineered soil covers must be constructed over the shale to support the growth of forest vegetation. A research site on South Bison Hill (SBH), a shale overburden dump at the Syncrude Canada Ltd. Mildred Lake Mine, has been used by researchers over the past decade to study the performance of a reclamation cover. This study was undertaken to improve the understanding of salt and moisture dynamics in the cover-shale system. In particular, the objective of this study was to develop an estimate of the net percolation rate through the cover soil and into the shale overburden. Stable isotope (ä2H and ä18O) measurements obtained from the pore water of soil samples were used to develop stable isotope profiles at various sampling locations along the slope and plateau of the SBH. Simulated profiles were then generated using 2D, finite element numerical modelling software and compared to the measured profiles. Model parameters were obtained from testing and the work of previous researchers. The model results revealed that the net percolation is greatest (32-50 mm/yr) for the plateau and mid-slope bench sample locations. Net percolation rates for sample locations on the slope were lower at 0-12 mm/yr. The results from the stable isotope modelling were utilized in a SO42- transport model to ascertain if calculated net percolation rates could explain measured salinity profiles. This modelling exercise revealed that calculated SO42- profiles are highly dependent on the assumed SO42- production rates in the shale, which is primarily attributed to pyrite oxidation. The model results showed the isotope-based net percolation rates could explain the measured SO42-profiles for a reasonable range SO42- production rates. The SO42- production rates calculated in the model were greatest for the plateau and mid-slope bench locations and lesser for the sloped locations. The model also showed that the mass of SO42- removed by interflow was minimal compared to the mass generated by pyrite oxidation and that net percolation is the dominant flushing mechanism at net percolation rates of 8 mm/yr or more.

Surface mining of oil sands in northern Alberta requires stripping of saline-sodic shale overburden, which is typically placed in large upland overburden dumps. Due to the chemical nature of this shale, engineered soil covers must be constructed over the shale to support the growth of forest vegetation. A research site on South Bison Hill (SBH), a shale overburden dump at the Syncrude Canada Ltd. Mildred Lake Mine, has been used by researchers over the past decade to study the performance of a reclamation cover. This study was undertaken to improve the understanding of salt and moisture dynamics in the cover-shale system. In particular, the objective of this study was to develop an estimate of the net percolation rate through the cover soil and into the shale overburden. Stable isotope (ä2H and ä18O) measurements obtained from the pore water of soil samples were used to develop stable isotope profiles at various sampling locations along the slope and plateau of the SBH. Simulated profiles were then generated using 2D, finite element numerical modelling software and compared to the measured profiles. Model parameters were obtained from testing and the work of previous researchers. The model results revealed that the net percolation is greatest (32-50 mm/yr) for the plateau and mid-slope bench sample locations. Net percolation rates for sample locations on the slope were lower at 0-12 mm/yr. The results from the stable isotope modelling were utilized in a SO42- transport model to ascertain if calculated net percolation rates could explain measured salinity profiles. This modelling exercise revealed that calculated SO42- profiles are highly dependent on the assumed SO42- production rates in the shale, which is primarily attributed to pyrite oxidation. The model results showed the isotope-based net percolation rates could explain the measured SO42-profiles for a reasonable range SO42- production rates. The SO42- production rates calculated in the model were greatest for the plateau and mid-slope bench locations and lesser for the sloped locations. The model also showed that the mass of SO42- removed by interflow was minimal compared to the mass generated by pyrite oxidation and that net percolation is the dominant flushing mechanism at net percolation rates of 8 mm/yr or more.

No description available.

No description available.

Thesis (Ph. D.)--University of Michigan, 1928.

No description available.

Partial replacement of cement by metakaolin is known to improve concrete durability, by refining the pore structure to improve fluid transport properties and by reducing the alkalinity of the pore solution to make ASR less problematic. A gap exists in the literature as to the salt scaling performance and magnesium sulphate performance of metakaolin concrete. 10 concrete mixes were cast at w/cm ratios of 0.4 and 0.5. In addition to metakaolin, grade 80 slag was used as well as CSA GU cement. All replacement levels were tested for setting properties, compressive strength, drying shrinkage, sulphate resistance, salt scaling, ASR mitigation and chloride diffusion characteristics according to the appropriate CSA and ASTM standards. It was found that metakaolin showed better performance in magnesium sulphate solutions than slag and that metakaolin concretes attained strength and other durability properties much faster than mixes without it. Keywords: metakaolin, ASR, sulphate, magnesium, scaling, setting, diffusion

Partial replacement of cement by metakaolin is known to improve concrete durability, by refining the pore structure to improve fluid transport properties and by reducing the alkalinity of the pore solution to make ASR less problematic. A gap exists in the literature as to the salt scaling performance and magnesium sulphate performance of metakaolin concrete. 10 concrete mixes were cast at w/cm ratios of 0.4 and 0.5. In addition to metakaolin, grade 80 slag was used as well as CSA GU cement. All replacement levels were tested for setting properties, compressive strength, drying shrinkage, sulphate resistance, salt scaling, ASR mitigation and chloride diffusion characteristics according to the appropriate CSA and ASTM standards. It was found that metakaolin showed better performance in magnesium sulphate solutions than slag and that metakaolin concretes attained strength and other durability properties much faster than mixes without it. Keywords: metakaolin, ASR, sulphate, magnesium, scaling, setting, diffusion