The aim of this thesis is to contribute to the understanding of iron metabolism, as a factor associated with cardiometabolic risk, by undertaking secondary data analyses. The objectives were to identify gaps in existing knowledge in terms of populations studied and alternative iron markers, and to attempt to fill the gaps with additional analyses and interpretation. Serum ferritin was the most widely available measure of iron status but the role of serum transferrin and soluble transferrin receptor (sTfR) levels was considered where available. I have taken a life-course approach with analyses in childhood and adulthood, and have included both intermediate factors such as the metabolic syndrome (MetS), and disease diagnoses of diabetes and cardiovascular disease as outcomes. Chapter one presents a review of empirical research literature on the relationship between iron metabolism and cardiometabolic risk, concepts surrounding iron markers and the study outcomes. This chapter also describes the gaps in understanding the iron-cardiometabolic risk relationship, which are subsequently explored in chapters two to six. Chapter two explores the link between serum ferritin and transferrin and MetS in cross-sectional and prospective studies of 725 Spanish children and 567 Chilean adolescents. I found associations between both ends of the ferritin distribution and MetS or glucose metabolism markers in different paediatric populations. For instance, whereas in the Spanish children there was a decrease of 0.02 SD units in the change of MetS score over time for every SD unit increase in ferritin, in the Chilean male adolescents being in the highest tertile of ferritin (v. the lowest) was associated with an increase of 0.25 SD units of MetS score. Furthermore, sustained high ferritin levels at various time points and gradual increase of ferritin during childhood were associated with higher MetS score in adolescence. The third chapter describes the association between serum ferritin status and MetS in adults in two cross-sectional studies of Scottish populations (2,047 individuals from Shetland Islands and 8,563 subjects from the Scottish Health Surveys (SHeS) 1995- 1998). I also examined the overall association between ferritin, MetS and each MetS component in adults, by conducting a meta-analysis and investigating potential relevant sources of heterogeneity for the association. Interestingly, ferritin levels were positively associated with MetS in the Scottish populations, but the association was not independent of the effect of covariates, mainly body mass index (BMI) and transaminase levels [Men Odds ratio (OR) 95% confidence interval (CI) 1.43(0.83- 2.46); Postmenopausal women OR (95%CI) 1.09(0.62-1.90); Premenopausal women OR (95%CI) 1.02(0.42-2.46), P > 0.05]. The meta-analysis supported this finding by describing hepatic injury markers and BMI as the major attenuating factors of the ferritin-MetS association. Chapter four investigates the association between sTfR or ferritin, and MetS in 725 Croatian adults in a cross-sectional study. There was no evidence of an association between sTfR and MetS [Men OR (95%CI) 1.35(0.90-2.02); Postmenopausal women OR (95%CI) 0.73(0.47-1.15); Premenopausal women OR (95%CI) 0.87(0.66-1.17), P > 0.05]. In contrast serum ferritin, was positively and independently associated with MetS in men and postmenopausal women (P < 0.05) [Men OR (95%CI) 1.78(1.31- 2.42); Postmenopausal women OR (95%CI) 1.71(1.12-2.62); Premenopausal women OR (95%CI) 1.24(0.85-1.80)]. These contrasting results suggest that different iron markers reflect different physiological processes other than iron metabolism. Chapter five evaluates the longitudinal association between serum ferritin and several cardiometabolic disease outcomes (CMDs) in the nationally representative SHeS 1995 and 1998 (n = 6,497). I found an independent positive longitudinal association between ferritin and cerebrovascular disease (CEVD), which was strengthened by using higher cut-points for increased ferritin [higher v. lowest sextile fully adjusted Hazard ratio(HR) 95%CI 2.08 (1.09-3.94), P=0.024], and a not significant association with coronary heart disease (CHD) after adjustment for covariates. My analyses confirmed the widely established association with type 2 diabetes (T2D) [whole sample fully adjusted HR 95% CI 1.59(1.10-2.34), P=0.006], even with serum ferritin within the normal range. The above set of observations confirm ferritin as biomarker mainly related to the development of T2D and identifies the need to investigate the association between ferritin and CEVD in other populations. Chapter six investigates whether ferritin is associated with risk for cardiovascular complications among people with T2D using cross-sectional study designs in two populations with differing baseline cardiovascular risk (Spanish study SIDIAP n=38,617) and (Edinburgh Type 2 Diabetes Study (ET2DS) n= 821) with additional analysis of follow-up data for ET2DS. Interestingly, ferritin levels were negatively associated with prevalence of cardiovascular disease, mainly CHD, in people with T2D in both studies [ET2DS OR (95%CI): 0.80(0.67-0.96), P=0.020; SIDIAP study: 0.85(0.83-0.88), P < 0.001). Ferritin was also negatively associated with incident cardiovascular disease in ET2DS: HR 95% CI: 0.39(0.16-0.93), P=0.035. Therefore, the association between iron status and CMD risk in people with T2D appears to differ from that in general populations in which a positive association has been more commonly described. In conclusion, serum ferritin is associated with cardiometabolic risk in different ways in a variety of populations. Inconsistent associations for other iron markers suggest that iron biomarkers reflect factors other than iron homeostasis that influence cardiometabolic risk. The association between iron markers and MetS appears to differ between populations. This thesis illustrates the complex relationship between iron metabolism markers, MetS and CMD, and identifies the need for further research on the topic in order to extend knowledge about pathophysiology and the potential for measures of iron status as biomarkers for CMD.

Thesis (Ph.D.)--McMaster University, 2004. / Supervisor: Harald D. H. Stöver.

No description available.

No description available.

Development of opto-electronic polymers has been focused on conjugated rigid-rod polymers which assume a para-catenated backbone yielding a rod-like configuration. As a consequence of their rigidity, the rod-like molecules display superior mechanical properties, thermo-oxidative stability and solvent resistance. The later two characters cause difficulties in processing these high-performance rigid-rod polymers. This in terms limits their applications in critical technologies, such as conducting polymers, nonlinear optics, and solid polyelectrolytes. In this study, chemical derivatives of the rigid-rod polymers were synthesized using pendants of propane-sulfonated ionomers to (1) enhance the solubility of the rigid-rod polymers, and (2) generate a solid polyelectrolyte suitable for energy storage. Extensive synthesis efforts were focused on generating monomers and polymers of propane-sulfonated poly(p-phenylene-benzobisimidazole), PBI, making it a water soluble electrolyte. Various analysis techniques were applied to ascertain the chemical structure and the purity of the monomers and of the polymers. The polymer molecular weight was also determined using viscometry. An intrinsic viscosity of 4.9 dL/g was achieved for the 2-sulfo-PBI and of 0.58 dL/g for the propane-sulfonated PBI with Na+ ionomer pendants

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 286-299). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 150-159). Also available on the Internet.

Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Deng,Yulin; Committee Member: Hsieh, Jeffery S.; Committee Member: Nair, Sankar; Committee Member: Singh, Preet; Committee Member: Yao, Donggang. Part of the SMARTech Electronic Thesis and Dissertation Collection.

No description available.

Bacterial membranes are dynamic structures, and contain lipid components that are individually simple, but complex as a whole system. The presence of charged functional groups makes them capable of interaction with ubiquitous environmental metals. Physiological responses of bacteria to metals, in preservation of membrane functions and integrity, are unclear. In this study, membrane lipid profiles were characterized for Shewanella putrefaciens CN32. Both fatty acid chemistry and hydrophilic headgroup chemistry were assayed, after growing the cells in a chemically defined medium spiked with Mn, V, or U. Cultures were grown in both aerobic and anaerobic conditions, to examine the effects of O2 and CO2 gases, as well as the combined effects of these gases with metals. The results were compared to scanning transmission X-ray microscopy (STXM) elemental maps and near-edge X-ray absorption fine structure (NEXAFS) spectra of isolated and purified S. putrefaciens CN32 envelopes at V, Mn, Ca, C, N, and O edges. It was found that there were strong correlations between membrane fluidity and fatty acid composition of strain CN32 membranes. The acyl chain chemistry was minimally affected by metal presence in the growth medium, however these subtle changes correlated with significant alterations in the fluid states of the membranes. Uranium seemed to fall outside this relationship, strongly stabilizing cell membranes. Metals in all treatments adsorbed to cell membranes, determined using either NEXAFS or electron microscopy, with the exception of V in aerobic conditions. Permeability effects of metal exposure to Ca(II), Cu(II), Mn(II), U(VI), V(IV), and Zn(II) were also assessed. Bacterial strains for these studies included S. putrefaciens CN32, Escherichia coli AB264 (wildtype K-12), Pseudomonas aeruginosa PAO1 wildtype, and Bacillus subtilis 168, in order to compare published data from the membrane chemistry of those organisms to S. putrefaciens CN32 membranes. Each metal had the same overall impact on each bacterial strain, regardless of variations in cell membrane and surface sugar chemistry, however the strengths of these effects were different for each organism. All metals with the exception of U permeabilized cell walls, while U rendered the membrane much less permeable. These impacts on permeability were concentration dependent from 0.001 mM to 1 mM concentrations. The research demonstrated that growth environment has a significant impact on the physicochemical state of bacterial membranes. Metals in those environments have varying complexation chemistry according to pH and redox conditions, and impact membrane attributes and dynamics depending on cell wall chemical composition. / This research was funded by the National Science and Engineering Research Council of Canada, as well as the Advanced Food and Materials Network.