Stormwater runoff can be a great concern in the State of Florida due to the impact the quality of the runoff water can have on the natural water bodies. Stormwater runoff can carry pollutants and sediments which can cause both physical and biological risks in an aquatic ecosystem such as a lake, river, or pond. Polymers, namely the chitosan-based dual polymer system, can be used remove the sediment from this runoff to ensure the safety of the state’s water bodies. Three soils are used in this testing: AASTO soil classifications A-3(sandy soil) and A-2- 4 (silty-sand), and a soil with a fine-grained limerock component. An optimum dose of the chitosan-based dual polymer system is first determined using jar testing. The optimum dose is the dose that reduces the final turbidity to 29 NTUS or below and creates significant flocs. The under dose and over dose are calculated based on the optimum dose. Using these dosages, field scale tests are conducted using two different treatment methods: a semi-passive treatment method and a passive treatment method. Whole effluent toxicity and residual chitosan tests are then conducted on the effluent from the field scale treatment methods. The passive treatment method is the best field scale treatment method when using the silty-sand and the soil with a fine-grained limerock component. The semi-passive treatment method is the best field scale treatment method when using the sandy soil. The passive treatment method with the silty-sand achieves a final turbidity of 123.9 NTUS (88.45% removal). The passive treatment method with the soil with a fine-grained limerock component achieves a final turbidity of 132 NTUS (83.86% removal). The semi-passive treatment method with the sandy soil achieves a final turbidity of 31.43 NTUS (82.04% removal). There is only significant toxicity associated with the tests using iv the effluent from the passive treatment method with the soil with a fine-grained limerock component which only uses the cationic polymer

No description available.

No description available.

No description available.

No description available.

No description available.

Electrospun nanofibers have been used for many applications, but a reliance on organic solvents limits their use in biomedical fields. In this study, we successfully electrospun nanofibers from aqueous chitosan-hyaluronic acid complex coacervates. We studied how solvent’ properties affected the average nanofiber diameter by using pure water as a solvent versus ethanol-water solutions. Experimentally, we investigated the effect of electrospinning apparatus parameters, such as how the applied voltage affected fiber formation and morphology. The smallest average nanofiber diameter was determined to be around 115 ± 30 nm when 3 wt% ethanol coacervate samples were electrospun using the applied voltage of 24 kV. Linear viscoelastic measurements were used to study the rheological characterization of complex coacervate with different salt concentrations and cosolvents (e.g., ethanol weight percent). Chitosan-hyaluronic acid nanofibers hold potential in biomedical applications such as wound dressing, tissue engineering, would healing scaffolds.

Polyelectrolyte complexes (PECs) between chitosan, a mucoadhesive, intestinal mucosal permeability-enhancing polysaccharide, and cellulose nanocrystals, rod-like cellulose nanoparticles with sulfate groups on their surface, have potential applications in oral drug delivery. The purpose of this research was to develop an understanding of the formation and properties of chitosan–cellulose nanocrystal PECs and determine their in vitro drug release properties, using caffeine and ibuprofen as model drugs. Cellulose nanocrystals were prepared by sulfuric acid hydrolysis of bleached wood pulp. Chitosans with three different molecular weights (81, 3·103, 6·103 kDa) and four different degrees of deacetylation (77, 80, 85, 89%) were used. PEC formation was studied by turbidimetric titration. PEC particles were characterized by FT-IR spectroscopy, scanning electron microscopy, dynamic light scattering, and laser Doppler electrophoresis. The formation and properties of chitosan–cellulose nanocrystal PEC particles were governed by the strong mismatch in the densities of the ionizable groups. The particles were composed primarily of cellulose nanocrystals. Particle shape and size strongly depended on the mixing ratio and pH of the surrounding medium. The ionic strength of the surrounding medium, and the molecular weight and degree of deacetylation of chitosan had a minor effect. Release of caffeine from the chitosan–cellulose nanocrystal PEC particles was rapid and uncontrolled. Ibuprofen-loaded PEC particles showed no release in simulated gastric fluid and rapid release in simulated intestinal fluid. Further evaluation studies should focus on the expected mucoadhesive and permeability-enhancing properties of chitosan–cellulose nanocrystal PEC particles. / Ph. D.

Consumer interest in supplementation with healthy omega-3 fatty acids (Ï 3 FA) has led to increased research in fortification of popular foods with these healthy fats. Yogurt, which is already popular, offers a functional food matrix to fortify with Ï 3 FA. Fish oil, a major source of two important long chain Ï 3 FA eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is an excellent source of Ï 3 FA enrichment into foods but brings problems of oxidation and off-flavors or odors when added to foods. Encapsulation, deodorized fish oil, and flavoring have been investigated to reduce these off-flavors and odors in food products while producing a fish oil-fortified yogurt. Discrimination of butter, fish or oxidized fish oil at 0.5% (wt/wt) levels was investigated in unflavored low-fat (1%) yogurt using untrained panelists (n=31) and sensory triangle tests. Five sensory attributes (lime, sweet, heat, acid, oxidized) were analyzed by experienced sensory panelists (n=12) in chile-lime flavored yogurts with butter, fish or oxidized fish oils added at low (0.43%) and high (1% wt/wt) levels. Analytical analysis for composition, fatty acid profile, and volatile chemistry of the yogurts was conducted. Consumer acceptance of a low-fat (1.5%) chile-lime flavored yogurt enriched with fish oil was investigated using a 9-point hedonic scale (1="dislike extremely", 9="like extremely"). Untrained panelists (n=31) were unable to differentiate 0.5% (wt/wt) levels of fish and butter oils in unflavored yogurts but were able to detect oxidized fish oil compared to butter or fish oil under in the same conditions. Experienced panelists (n=12) found significant differences (p<0.05) in lime and acid attributes in chile-lime flavored yogurts containing 1% (wt/wt) oxidized fish oil compared with 0.43 and 1% (wt/wt) butter and fish oil yogurts and 0.43% (wt/wt) oxidized fish oil yogurts. Oxidized attributes were determined as significantly different (p<0.05) by experienced panelists in chile-lime yogurts with 1% (wt/wt) fish oil, 0.43 and 1% (wt/wt) oxidized fish oil added. The acceptance of a fish oil-enriched chile-lime flavored yogurt was neutral ("neither liked nor disliked") by consumers (n=100) but 44% rated the product "like slightly" (6 of 9) or greater. A successful chile-lime flavored yogurt offering a novel savory flavor was formulated from pre-pasteurization addition of fish oil to deliver more than 145 mg DHA+EPA/170 g serving of yogurt. / Master of Science

A major challenge in hepatic tissue engineering is that liver cells rapidly lose their phenotype in in vitro cell culture systems. For this reason, it is necessary to design biomaterials that can support and enhance hepatic functions. Hepatocytes have a surface protein, called the asialoglycoprotein receptor (ASGP-R), which interacts with galactose via a specific receptor-ligand interaction. Polyelectrolyte multilayers (PEMs) were prepared by the layer by layer method, which is based on electrostatic attractions between oppositely charged polyelectrolytes (PEs). Anionic (hyaluronic acid) and cationic (chitosan and galactosylated chitosan) PEs were used in the fabrication of detachable, free-standing PEMs. The main focus of this study is the design of PEMs comprised of 50 bilayers of PEs. PEMs that contained galactose functional groups were assembled with either 5 or 10 bilayers of galactosylated chitosan (5 - 10 % of galactosylation). Optical properties, solvent stability and surface topography of the PEMs were measured. / Master of Science