Three-dimensional (3D) tissue models have significantly improved our understanding of structure/function relationships and promise to lead to new advances in regenerative medicine. However, despite the expanding diversity of 3D tissue fabrication methods, in vitro approaches for functional assessments have been relatively limited. Herein, we describe the guidance of primary endothelial cells (ECs) in an agarose hydrogel scaffold that is chemically patterned with an immobilized concentration gradient of vascular endothelial growth factor 165 (VEGF165) using multiphoton laser patterning of VEGF165. This is the first demonstration of this patterning technology to immobilize proteins; and the first demonstration of immobilized VEGF165 to guide endothelial cell growth and differentiation in 3D environments. It is particularly compelling that this 3D hydrogels provide an excellent biomimetic environment for stem cell niche, thereby offering a new approach to study stem cell biology. In this thesis, we focused on the retinal stem cell niche, investigating cellular interactions between retinal stem and progenitor cells (RSPCs) and endothelial cells (ECs). By using this 3D in vitro model, we demonstrated the synergistic interactions between RSPCs and ECs wherein RSPCs migrated into 3D gels only in the presence of ECs and RSPCs stabilized EC tubular-like formations. Moreover, we characterized the contact-mediated effects of ECs on RSPC fate in terms of proliferation and differentiation.

Anaerobic digestion of excess biological wastewater treatment sludge (WAS) from pulp mills has the potential to reduce disposal costs and to generate energy through biogas production. The organic matter in WAS is highly structured, which normally hinders biogas production. This study investigated three methods of pretreating WAS from two different pulp mills before anaerobic digestion to improve biogas yield and production rate. The three pretreatment methods tested were: i) thermal pretreatment at 170oC, ii) caustic pretreatment at 140oC and pH 12, and iii) sonication at 20 kHz and 1 W/mL. Thermal pretreatment proved to be the most effective, increasing biogas yield by 280% and 50% and increasing production rates 300-fold and 10-fold for the two samples, respectively. Caustic pretreatment showed similar results, but resulted in the formation of soluble non-biodegradable compounds. Sonication was the least effective pretreatment and did not substantially increase biogas yield, but increased biogas production rate.

The objective of this thesis is to better understand the impact of paper and printer types on xerographic print quality. To achieve this objective, commercially printed samples comprising of ten different paper substrates printed using three different xerographic printers were examined. The print quality of these samples was assessed in terms of print microgloss and its nonuniformity, print density, print and gloss mottle, print roughness, and visual ranking. This study showed that print mottle conducted by Fast Fourier Transform produced the best correlation with visual ranking at the size range of 0.1 - 1mm, while print gloss mottle was found to affect print quality regardless of the mottle size. Brightness, opacity, basis weight, gloss 75, and roughness of these paper substrates were found to have the most significant effect on print quality. All of the optical properties of paper included in this analysis showed a strong correlation to print quality.

In this work the methodology is developed to study spreading and penetration of a custom ink-jet ink formulation, containing hydrophobic cationic crystal violet dye, ethoxylated surfactant, and ink solvent marked by lithium salt. With a new technique utilizing Time-of-Flight Secondary Ion Mass Spectrometry imaging, the ink component distribution and its effect on print quality of uncoated and coated papers are evaluated. High spatially resolved images obtained by ToF-SIMS illustrate differentiation of individual ink components, with ink solvent spreading more than the dye in all paper samples. Uncoated papers show greater and more irregular spreading leading to poor edge definition and poor print quality. Large separation of the dye from the solvent in the vertical direction of multipurpose and photo glossy ink-jet paper suggests a step-wise progression of ink penetration: ink flows through a more porous structure in the x-direction before advancing to the next sublayer in the z-direction of paper.

The pulp and paper industry has been struggling to meet the new and stringent TRS (Total Reduced Sulphur) emission compliance standards established in recent years. However, a new approach by some regulatory bodies gives intricate operational parameters a new and important role in achieving environmental compliance. TRS compounds that cause the distinctive pulp mill odour, originate from sodium sulphide in white liquor used in the kraft pulping process. Up to 20% of TRS emissions could originate from the lime kiln and lime mud solids content is one of the operational parameters that could help reduce the TRS emissions from the lime kiln. Residual sodium sulphide in the lime mud that results in TRS gases, is dissolved in the moisture content of the mud. Although efficient lime mud washing can remove most of the residual sodium sulphide, the remaining moisture content of the mud still contains some sodium sulphide. Therefore, improved lime mud dewatering can be effective in reducing the TRS emissions from the lime kiln. Data presented in this study confirms that as the lime mud solids content increases, TRS emissions from the lime kiln decrease. Data analysis demonstrates a negative linear correlation at 5% significance level between TRS emissions and lime mud solids.

The overall objective of this research is to identify and optimize enzymatic applications that have the potential to degrade middle lamella lignin, so as to decrease economic and environmental costs associated with the production of mechanical pulp. Non-productive binding of enzyme to lignin in lignocellulosic biomass reduces enzyme availability and efficiency. The elucidation of non-productive binding behavior between hydrolytic enzymes and lignocellulosic substrates could significantly improve the efficiency of corresponding industrial bioprocesses. The first part of this report presents a study that characterizes non-catalytic interactions between enzymes and fibre. The second part of this report presents the biochemical and mutational studies of a novel, small laccase SCO6712 from Streptomyces coelicolor. The findings from this research support the design, control, and optimization of enzymatic treatments of lignocellulosic fibres in the pulp and biofuel industries.

A hygroexpansimeter, cockling tester and a novel x-ray microtomography technique were employed to characterize hygroexpansivity as well as macro- and micro-scale cockling of wood-free paper sheets containing varying amounts of aspen high yield pulp (HYP) in order to validate its potential applicability in inkjet printing. Results from the hygroexpansimeter confirm previous findings that substitution levels of 30% and above lead to a slight deterioration of hygroexpansivity; however, contrary to the expected outcome, aspen HYP did not necessarily result in a higher tendency to form cockles. In fact, a comparison of the cockling behaviour between various paper samples and commercial paper substantiates that up to 40% of aspen HYP can replace hardwood bleached Kraft pulp. The preservation of out-of-plane dimensional stability in non-coated samples is most likely due to the increase in bending stiffness of the paper as it became bulkier with more aspen HYP.

This Masters thesis investigates the ligand–particle binding interactions in the thiol–capped CdTe nanoparticles and dye adsorbed gold nanoparticles. In the CdTe nanoparticles, Raman modes corresponding to the CdTe core, thiol ligand and their interfacial layers were observed and correlated to the different nanoparticle properties. To the best of our knowledge, this is the first time that such strong Raman modes of the thiol-capped nanoparticles in aqueous solution have been reported. In the gold nanoparticle systems, gold–citrate binding interactions were observed as well as adsorption of the Raman dyes and binding with the polyethyleneglycol polymer coating and phospholipid coating. These observations coincided with findings from conventional optical techniques. In addition, gold nanoparticles were found to carbonize at high pump power and prolonged exposure time. In summary, the two nanoparticle characterizations demonstrated the high sensitivity and nondestructive nature of the photonic crystal fiber for Raman spectroscopy.

Microemulsions have gained interest from the pharmaceutical industry due to their ability to co-solubilize hydrophilic and lipophilic drugs, and to provide enhanced drug penetration. In this work, thermosensitive gelatin- and poloxamer 407-stabilized microemulsion-based gels (MBGs) were formulated using alcohol-free, low toxicity and low viscosity lecithin-based linker microemulsions. The addition of gelatin to water-rich bicontinuous microemulsions induced the formation of clear viscoelastic gels containing an oil-rich microemulsion as the gelatin seemed to dehydrate the original microemulsion. The addition of poloxamer 407 to water-continuous microemulsions produced MBGs with different gelation temperatures. High concentrations of lipophilic components in the microemulsion, particularly the oil, reduced sol-gel transition temperature, while hydrophilic components increased sol-gel transition temperature. Gelatin and poloxamer MBGs provided desirable viscoelastic properties for ophthalmic and transdermal applications with minimal impact on the transport properties of the original microemulsions.

To improve biogas production from lignocellulosics, methanogenic microbial enrichments were prepared from moose rumen fluid, beaver droppings, and internal circulation (IC) reactor granules amended with cellulose, pine needles, lignosulphonate, tannic acid, and poplar hydrolysate. Tannic acid delayed methanogenesis compared to cellulose only enrichments, both by reducing initial rates (up to 50% in beaver dropping cultures) and increasing lag times (up to 50 days in moose rumen cultures). Biogas yields from poplar hydrolysate were 56 % by beaver droppings, 51% % by IC granules, and 31 % by moose rumen enrichments. Bacterial community profiles, determined via denaturing gradient gel electrophoresis (DGGE) showed divergent populations between enrichments. Enrichment on pine needles or poplar hydrolysate promoted bioconversion of post extraction wash (PEW), and beaver dropping enrichments fed pine needles equaled the yield (about 23%) from IC granules. Together, the DGGE and PEW results provide evidence of acclimatization to previously recalcitrant feeds.