Mercury-selenium (Hg-Se) interaction is perhaps the most documented bioantagonism. Since its discovery in the 1960s, extensive studies have been carried out on the wide occurrence, chemical mechanisms, and toxicological significance of this bioantagonism. However, major knowledge gaps exist in the underlying mechanism at the molecular level which is the objective of this present research. To study molecular level mechanism of this bioantagonism, four new MeHg-selenoamino acid namely, methylmercury-D,L-selenopenicillaminate, methylmercury-L-selenoglutathionate, and two methylmercury-L-selenomethioninate complexes (one via a Hg-Se bonding and the other via Hg-N bonding) were synthesized and characterized by NMR, FT-IR and mass spectrometry. Their structural and electronic properties were studied by X-ray crystallography and quantum mechanical calculations. These studies reveal that all four complexes chemically and structurally resemble their sulfur analogues. This suggests that mimicry could play a role in the MeHg-Se antagonism. Chemical coupling values from NMR suggest that MeHg+ has stronger affinity for Se than for S. It has long been proposed and analytically proven that mercury selenide, HgSe(s), is the end product of the Hg-Se bioantagonism. However, the pathway of its formation in biological systems was poorly understood. Experiments carried out in this study suggested that HgSe(s) could be formed from both inorganic Hg and MeHg in the presence of Se. In the case of MeHg, we found that its binding with selenoamino acids could result in the demethylation of MeHg and formation of HgSe nanoparticles. NMR and gas chromatography – mass spectrometry (GC-MS) studies confirmed the presence of bis(methylmercury) selenide (BMSe) and dimethylmercury as reaction intermediates based on which a demethylation pathway was proposed. Inorganic Hg interacts with selenite in presence of glutathione (GSH) and form HgSe1-xSx (0 < x < 1) nanoparticles via a black solution or precipitate. The dissolution/precipitation is reversible upon adjustment of pH. UV-visible spectra, TEM and XPS analyses revealed that the black solution is HgSe1-xSx nanoparticles with diameter < 5 nm which at high pH and upon separation becomes sparingly soluble. This study provides a new plausible explanation of tissue distribution patterns of HgSexS1-x in biological systems.

Agriculture contributes significantly to national and global greenhouse gas (GHG) inventories but there is considerable control over management decisions and changes in production methods could lead to a significant reduction and possible mitigation of emissions from the sector. For example, conservation tillage practices have been suggested as a method of sequestering atmospheric carbon dioxide (CO2), however, many questions remain unanswered regarding the short-term efficacy of the production method and knowledge gaps exist regarding possible interactions with essential nutrient cycles, and the production of non-CO2 GHGs, such as nitrous oxide (N2O). Between autumn 2005 and 2009, a micrometeorological flux system was used to determine net CO2 and N2O exchange from an annual cropping system situated on clay soil in the Red River Valley of southern Manitoba. Four plots (4-ha each) were independently evaluated and planted to corn in 2006 and faba bean in 2007; in 2008, two spring wheat plots were monitored. As well, during the non-growing season in 2006-2007 following corn harvest, a second micrometeorological flux system capable of simultaneously measuring stable C isotopologue (12CO2 and 13CO2) fluxes was operated at the site. Tillage intensity and crop management practices were examined for their influence on GHG emissions. Significant inter-annual variability in CO2 and N2O fluxes as a function of crop and related management activities was observed. Tillage intensity did not affect GHG emissions from the site. After accounting for harvest removals, the net ecosystem C budgets were 510 (source), 3140 (source) and -480 (sink) kg C/ha/year for the three respective crop years, summing to a three-year loss of 3170 kg C/ha. Stable C isotope flux measurements during the non-growing season following corn harvest indicated that approximately 70 % and 20 – 30 % of the total respiration flux originated from crop residue C during the fall of 2006 and spring of 2007, respectively. The N2O emissions at the site further exacerbated the net global warming potential of this annual agroecosystem.

An area scan colour camera was used to acquire images of single kernels of Canada Western Red Spring (CWRS) wheat from different growing locations (nine locations in the year 2007, eight locations in the years 2008 and 2009) in Western Canada. Two sample presentation methods were used. In the first method, fifteen kernels from a single location were imaged in a single image and in the second method one kernel from each location were imaged in the same image. Images of individual kernels of barley and rye were also acquired for a classification study. Bulk images of heaped and flat CWRS samples, heaped and flat barley samples, and images of CWRS wheat mixed with different proportion of foreign materials (0%, 2%, 5%, 10%, 20% barley) were acquired. Morphological, colour, and textural features from single kernel images and colour and textural features from bulk grain images were extracted by a program developed by researchers at the Canadian Wheat Board Centre for Grain Storage Research. The top 30 features from the single kernel images of CWRS wheat samples from different growing locations and also different crop years were compared by Scheffe's test. Image features from two types of presentation methods were also compared. Representative of a composite sample which was generated by randomly selecting kernels from each location was compared with individual locations. Three-way classification of CWRS wheat, barley, and rye was done using the top 30 features. For bulk grain image analysis, features from flat bulk grain samples and heaped bulk grain samples were extracted and compared. Image features of CWRS wheat mixed with different percentages of barley were examined, and a cross-validation discriminant classifier was developed to classify CWRS wheat mixed with different percentages of barley. Classifications were also conducted using flat grain as training, flat and heaped grain in testing. Results from this study indicated that most image features from different growing locations and also different crop year samples had significant differences. However, these differences did not influence three-way classification of CWRS wheat, barley, and rye. Features from the composite sample were compared with those from each location. Composite sample features were different from each location. Hence composite samples may not be representative for all locations. However three-way classification using composite sample features gave similar results as in the case of using each location samples. Canada Western Red Spring wheat and barley samples were used in comparing the image features of flat grain and heaped grain. Results indicated that image features from flat grain were different from heaped grain samples. However a two-way classification applied to heaped and flat CWRS wheat, and also heaped and flat barley, gave perfect classification accuracies. Classification models trained using flat grain also gave perfect classification accuracies when tested using flat and heaped grain. A comparison of the top 30 features extracted from images of CWRS wheat mixed with different proportion of barley revealed that grain image features changed after mixing barley. In classification of CWRS wheat mixed with 0, 2, 5, 10, and 20% barley, classification accuracies of 100, 99, 96, 95, and 98% were obtained, respectively.

The Himalayan region of India has a surprisingly fragile ecosystem due in part to its geomorphic characteristics. In recent years the Himalayan ecosystem has been disturbed in various ways by both human and natural processes. Large developments threaten ecosystems in the area modifying local land use and subsistence patterns. This has important implications for the sustainable livelihoods of the local communities. People in these areas are very concerned about the lack of inclusion in development decision-making processes and the negative effects of development on their livelihood. Protest actions are spreading throughout Himachal Pradesh, not only to stop developments but also to re-shape how developments are taking place. The village of Jagatsukh was selected for in-depth study. That is where people started to organize around the Allain Duhangan Hydro Project and also where the protest actions in relation to the Hydro Project actually started. The overall purpose of this research was to understand the role of protests as a vehicle for public participation in relation to decisions about resources and the environment and to consider whether such movements are learning platforms for action on sustainability.

The continuous advancement in wireless communications technology demands new approaches to improving the capacity of existing radio links. The high data throughput required can be achieved by the complete utilization of space, time and polarization diversities inherent in any propagation environment. Among the different propagation scenarios, the indoor channels represent a particularly challenging problem given the number and complexity of interactions between the transmitted signal and the environment. This dissertation explores the interrelation between propagation physics and space-time-polarization diversity based on a novel high resolution channel sounding and reconstruction technique. First, a method to reconstruct the indoor complex channel response based on a limited set of samples and the elimination of the interference using deconvolution techniques is presented. Then, the results for the joint angle-of-arrival, delay characterization and depolarization of electromagnetic waves are presented. Finally, a novel approach to using depolarized multipath signals to boost the receiver signal-to-noise performance is presented. The current study shows that full utilization of the diversities of channel novel wireless systems can be proposed with significant improvement in capacity.

Food protein-derived peptides have increasingly become important sources of ingredients for the formulation of therapeutic products. The main aim of this work was to study the in vitro and in vivo bioactive properties of structurally diverse group of peptides produced through enzymatic hydrolysis of flaxseed proteins (FP). Hydrolysis of FP with seven proteases followed by fractionation into low-molecular-weight (LMW) cationic fractions yielded multifunctional peptides that inhibited angiotensin converting enzyme (ACE) and renin activities, which are molecular targets for antihypertensive agents. The LMW peptides also exhibited antioxidant properties by scavenging free radicals and inhibiting amine oxidase activity. The peptide fractions showed inhibition of calmodulin-dependent phosphodiesterase, an enzyme that has been implicated in the pathogenesis of several chronic diseases. Moreover, FP hydrolysis with thermolysin and pronase followed by mixing with activated carbon yielded branched-chain amino acids (BCAA)-enriched multifunctional peptide mixture (Fischer ratio of 23.65) with antioxidant properties and in vitro ACE inhibition; Fischer ratio of 20.0 is considered minimum for therapeutic purposes. The BCAA-enriched peptide product can be used in clinical nutrition to treat muscle wasting symptoms associated with hepatic diseases. Furthermore, an arginine-rich peptide mixture (31% arginine versus 11% in the original flaxseed protein) was produced by hydrolysis of FP with trypsin and pronase followed by separation using electrodialysis-ultrafiltration. Arginine plays important physiological roles especially as precursor to vasodilator, nitric oxide. The arginine-rich peptide mixture exhibited in vitro ACE and renin inhibition and led to decreased systolic blood pressure (–17.9 and –11.7 mmHg, respectively at 2 and 4 h) after oral administration to spontaneously hypertensive rats. For the first time in the literature, we showed that arginine peptides have superior physiological effects when compared to the amino acid form of arginine. Lastly, quantitative structure-activity relationship studies using partial least squares (PLS) regression yielded two predictive models for renin-inhibiting dipeptides with z-scales amino acid descriptors. The PLS models indicated that hydrophobic and bulky side chain-containing amino acids contribute to renin inhibition if present at the amino- and carboxyl-terminal of dipeptides, respectively. Based on this study, Ile-Trp was discovered as potent renin-inhibiting dipeptide, and may serve as a useful template for the development of potent antihypertensive peptidomimetics.

E. coli O157:H7 has been found to survive in dry sausages and cause disease. Isothiocyanates have been studied for their capacity to eliminate pathogens from foods and are attractive from the consumer perspective because of their natural origin. There is a need to better understand how isothiocyanates kill microorganisms and their behaviour in food matrices. It was found that glutathione and cysteine naturally present in meat can react with AIT, forming a conjugate with no or low bactericidal activity against an E. coli O157:H7. In addition, AIT presented higher anti-E. coli activity at lower pH values; therefore, it should be more efficient in acid foods. AIT was also found to inhibit the activity of thioredoxin reductase and acetate kinase; hence, enzymatic inhibition may represent a way in which AIT kills E. coli O157:H7. Mustard powder is used as a spice (active myrosinase) and/or binder (inactive myrosinase) in meat products. Both of these powders killed E. coli O157:H7 in dry fermented sausage. This was not expected since the powder lacking myrosinase is not able to produce isothiocyanates. Starter cultures and E. coli were found to consume significant amounts of glucosinolates. Pediococcus pentosaceus UM 121P and Staphylococcus carnosus UM 123M (higher myrosinase-like activity) were compared against P. pentosaceus UM 116P + S. carnosus UM 109M for their ability in reducing E. coli viability in dry sausage. Sausage batches containing powders of hot mustard, cold mustard, autoclaved mustard and no powder were prepared. Both pairs of starters yielded similar results. Reduction >5 log CFU/g of E. coli O157:H7 occurred after 31 d for hot powder and 38 d for cold powder; there was no reduction in the control. E. coli O157:H7 itself has greater effect on glucosinolate degradation than either pair of starters, which may be more important in determining its survival. Autoclaved powder caused >5 log CFU/g reduction after 18 d. This may be the result of synergistic/additive interaction among E. coli O157:H7 myrosinase-like activity, the presence of newly formed/released antimicrobials in the autoclaved powder and the multiple hurdles present in the dry sausage. Autoclaved mustard powder has potential as a novel food ingredient for the meat industry.

This research focuses on studying the microstructure of alloy 909, its susceptibility to oxidation at elevated temperatures (~700°C) and substrate coatings compatibility with high velocity oxy fuel (HVOF) sprayed oxidation resistance coatings. The characterization work involved in studying the microstructure of Incoloy 909 at three heat treated conditions namely solution treated condition (ST), commercially recommended solution heat treated and aged condition (STA), and solution treated and over aged condition (STOA) using optical microscopy, analytical scanning electron microscopy, and analytical transmission electron microscopy. The oxidation susceptibility were investigated at elevated temperatures of bare and coated alloy 909 substrates by subjecting test materials to isothermal and thermal cycle testing. The microstructure of alloy 909 in the ST condition showed only the presence of blocky Laves phase. The Laves phase in this alloy is a well known for its grain pinning effect that prevents excessive grain growth. In the STA condition, the microstructure revealed the presence of fine gamma prime, intergranular and intragranular Laves phase and occasionally gamma prime precipitates orienting in a platelet form ready to transition into the epsilon phase. In the STOA condition, the microstructure consisted of Laves phase in inter and intragranular locations, and a copious amount of Widmanstatten type epsilon phase. Incoloy 909 was observed to form oxide scales in both isothermal and cyclic thermal exposures, the oxide scale consisted of distinct outer and inner scales in the micrographs. The comparison base alloy (alloyl 718) used in this study surprisingly did not show any visible presence of oxide scale after 1000 hour exposure at ~700°C. Three coatings (CoNiCrAlY, 718 , and NiAl) were sprayed on alloy 909 and alloy 718 test coupons using the HVOF process to investigate the compatibility of the coatings with the substrate. The test results points out that all the coatings were compatible with 718 substrate and only one coating (NiAl) was found compatible with the Alloy 909 substrate, indicating that the coatings that are compatible with one substrate may not be compatible with another alloy within the same family of alloys.

Whereas the literature on English as a Second Language (ESL) instruction has flourished over the last thirty years, very little in the literature addresses issues concerning research with participants who are non-native speakers of English (NNSE). For this qualitative study, six researchers affiliated with a western prairie university were interviewed and asked to reflect on what ethics means to them, which ethical issues are of greatest importance to them when working with NNSE participants, and the role of research ethics boards (REBs). Issues of language, culture and power were found to be key themes as was a deep respect on the part of the researchers towards their participants. In addition, REBs were found to be lacking and in need of reconsideration. These findings suggest that there exists a distinction between institutional ethics (ethics as it pertains to REBs) and individual ethics (ethics as envisioned by researchers).

The central nervous system (CNS) melanocortin signaling pathway plays a critical role in the regulation of metabolism. However, the regulatory effects of CNS melanocortin signaling on hepatic lipid metabolism and fatty liver disease have not been well established. Although the activity of the CNS melanocortin system is regulated by metabolic signals, the mechanism for this regulation is not fully understood. Variants of the FTO (fat mass and obesity-associated) gene are associated with obesity and FTO is expressed in the hypothalamic neurons including proopiomelanocortin (POMC) neurons. Therefore, it is hypothesized that hypothalamic FTO plays a role in the regulation of metabolism by mediating the effect of metabolic signals on hypothalamic melanocortinergic neurons, and that impairments in this regulation may cause metabolic impairments including obesity and fatty liver disease. Intracerebroventricular (i.c.v.) treatment with SHU9119, a melanocortin antagonist, increased hepatic lipid accumulation and the expression of genes encoding lipogenic enzymes in lean mice. Conversely, i.c.v. treatment with MTII, a melanocortin agonist, reduced the expression of hepatic lipogenic genes in association with reduction in body weight in ob/ob mice, a mouse model of fatty liver disease. Immunohistochemical analysis demonstrated that Fto is co-expressed in both POMC and agouti-related protein (AgRP) neurons in the mouse hypothalamus. Fto mRNA and protein expression was reduced by fasting and increased by glucose treatment in nutritionally important hypothalamic nuclei. Fasting-induced reduction in hypothalamic Fto expression was observed in both lean wild-type and obese ob/ob mice, while the stimulatory effect of glucose on hypothalamic Fto expression was absent in ob/ob mice. These findings support the hypothesis that central melanocortin signaling regulates hepatic lipid metabolism in part by regulating de novo lipogenesis. Impairments in the central melanocortin signaling lead to the development of hepatic steatosis, while enhanced melanocortin signaling may be beneficial in reversing abnormal hepatic lipid metabolism in fatty liver disease (Poritsanos et al., 2008). These findings also support the hypothesis that Fto is expressed in the hypothalamic melanocortinergic neurons and is regulated by metabolic signals involving changes in CNS glucose availability and/or glucose action. Impairments in this regulation may cause metabolic impairments including obesity and fatty liver disease.