The published benefits of polymeric nanoparticles as a system for antioxidant delivery have encompassed topics of improved oral delivery, bioavailability, and modified release to name a few. Generally accepted as safe polymers Poly(lactic-coglycolic acid) and the mucoadhesive chitosan were selected to entrap alpha-tocopherol and lutein. This study proposed to assess the physical stability of PLGA and Chi/PLGA nanoparticles with entrapped bioactives in varying biological suspension medias ( water, pbs, hbss and cell media). Also, to assess the chemical stability of the entrapped antioxidants lutein and alpha-tocopherol within the same media as deemed relevant for in-vitro and and in-vivo studies. Of the tested media, physical stability was not media dependent for the PLGA(AO) or PLGA/Chi (AO) particles. Neither the size nor the PDI appeared significantly affected by the media it was re-suspended. Entrapped alphatocopherol remained chemically stable throughout the time suspended in the various biological mediums. While the lutein emulsion stability decreased over time, the NP(L)demonstrated improved stability. Also, the entrapped lutein stability was not dependent on the selected medium. Identifying any potential effects of suspension media on polymeric nanoparticles and the entrapped bioactive affords the opportunity to improve analysis of more robust or complex nanoparticle studies. Also, presented are considerations that should be taken prior to design of an experiment.

Nanotechnology has become integrated in commercial, industrial and medical products, and its use has grown exponentially in the past several years. Although potential applications of nanoparticles (NPs) are numerous, concerns about their water quality, environmental, and human health impacts remain unclear. Crayfish are ubiquitous to streams and wetland habitats, are used as a food source, and inhabit areas that could be impacted by water quality issues. Numerous studies have been conducted on the toxicity of various classes of agricultural pesticides and oils to crayfish (Procambarus clarkii) as a non-target organism. However, there is little evidence published on chronic toxicity of NP to crayfish. The first objective of this study was to estimate the 28 day toxicity and bioaccumulation of the three most produced nanoparticles, Ag, ZnO, and TiO2, in a laboratory adult crayfish model. The organisms were exposed to different Ag, ZnO, and TiO2 nanoparticle solutions at concentrations of 0, 100, 500, and 1000 𝜇g/mL. AgNO3 and KNO3, and Zn(NO3)26H2O and KNO3 were used as bulk controls for Ag and ZnO treatments, respectively. Dead crayfish were removed and preserved then examined for metal accumulation and pathological changes in behavior. Metal accumulation in major organs was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Results indicate that as the concentration of NP increases the uptake of metal in tissue also increases. In this case, the chemical rankings of toxicity are as follows: AgNO₃ > Zn(NO₃)₂ > AgNP > ZnO > KNO₃ > TiO₂. Silver accumulated in gill tissue 3 times more in AgNO3 treatments than in AgNP treatments. In abdominal tissue, silver accumulated 4 times more in AgNO3 treatments than in AgNP treatments. Zinc accumulated in gill tissue 2 times more in Zn(NO₃)₂ treatments than in ZnO treatments. The second objective was to estimate the bioaccumulation of the nanoparticles: Ag, ZnO, and TiO2 in a mesocosm adult crayfish model. From previous experiments, we determined the following concentrations for each tank: AgNPs 20 mg/L, ZnO 50 mg/L, and TiO2 100 mg/L. A 0 mg/L control tank was also used. Three crayfish were removed from each tank and preserved for analysis weekly. Soil samples were taken bi-weekly. ICP-OES was used to look at the accumulation of the metals in the gill and abdominal tissues as well as the soil samples. Results indicate that bioaccumulation occurs in tissues in fluctuating trend rather than an increasing trend.

Developing materials that are environmentally friendly and capable of high performance is important to maximize the efficiency and success of coastal restoration projects. Louisiana is losing large amounts of coastal land each year, while suffering 90% of the United States coastal wetland loss. Some areas have begun to implement physical structures to dissipate wave energy and accrete sediment. Recent technological advances have allowed the transformation of these structures into engineered ecosystems, with a focus on oyster accumulation. These ecosystems support the growth of oysters, Crassostrea virginica, which serve to improve water quality and protect shorelines through filtration and wave energy attenuation. An evaluation of scale-model reefs showed bioaccumulation on various cement mixtures, as well as the customization available with the implementation of artificial reefs. This customization also allows the use of bioengineered oyster reefs in the creation of more sustainable coastal homes, with the combination of various architectural techniques, as structural and ecological members. Artificial reefs can be used for protection of the homes and shorelines, while also serving as a valuable food source, not only through oyster growth, but through the attraction of a large number of crab, shrimp and fish, as well. Alternative methods of oyster harvest are also explored in this study. An artificial cultch material showed insignificant differences (p=0.0726) in oyster growth when compared to oyster shell, the typical substrate used in oyster production. The artificial cultch could be used as a viable substitute, in areas where oyster shell is either limited or expensive. This body of work shows the potential for the use of sustainable and ecologically valuable artificial materials in coastal and oyster reef restoration.

High demand for energy and increasingly expensive petroleum prices led to development of new alternative fuels for transportation, such as bio-ethanol and bio-diesel. Even though a cost reduction in the production of cellulolytic enzymes is occurring, the conversion of plant cellulose into sugars still remains an expensive and slow process. Pretreatment of lignocellulose materials to remove lignin and alter physical/chemical structures significantly improves hydrolysis of cellulose to give high yield of sugars. In this study, ultrasonic pretreatment of energy cane bagasse was used in the presence of ammonia (NH4OH) to enhance the saccharification process by separating lignin, cellulose and hemicellulose from each other in biomass. The process performance was investigated as a function of low ultrasonic frequency (20, 20.5, 21 kHz) at a power level of 100 W for the reaction time of 30 min at 80 to 90°C reaction temperature. The pretreatment was performed for four different combination mixtures:(1) energy cane bagasse with 28% NH4OH and water at a ratio of 1:0.5:8 (w:w:w) and processed immediately, (2) energy cane with water at a ratio of 1:8.5 (no ammonia) and processed immediately, (3) energy cane soaked with 28% NH4OH and water with the same ratio for 3 hours, then drained and pretreated ultrasonically and (4) energy cane soaked with water with the same ratio for 3 hours (no ammonia), then drained and pretreated ultrasonically. Composition analyses were performed after pretreatment to quantify glucose yield and lignin removal rates. Enzymatic hydrolysis tests were also performed to quantify the sugar yield. Results for composition analysis for different pretreatment combinations were obtained against the control. The objective was to find the best frequency for which high glucan % and cellulose digestibility % for degrading them to simple sugars were obtained. The pretreatment process was performed again for all the four combination mixtures mentioned as a function of pretreatment reaction time (30, 45, 60 min) with constant frequency at 20 kHz, power level of 200 W and increase in reaction temperature of above 120 ° C. All the energy cane combination mixtures were pretreated along with their respective controls (without ultrasonic frequency). The cellulose digestibilities among various combination mixture samples based on a particular frequency were not statistically significant but varied significantly compared to the untreated energy cane bagasse. The energy cane bagasse with 28% NH4OH and water for 60 min reaction time obtained the highest cellulose digestibility of almost 44% for both non-soaked and soaked samples compared to 20.44% for the untreated energy cane bagasse (control). Energy cane bagasse with water for 60 min reaction time obtained cellulose digestibility of 34.14%, whereas the water soaked and drained sample for 60 min reaction time obtained cellulose digestibility of 38.12%. The maximum theoretical glucose yield was 24.29 g / 100 g of dry biomass for the combination mixture of energy cane bagasse with 28% NH4OH and water for 60 min reaction time. Theoretical glucose yield for energy cane bagasse with 28% NH4OH and water soaked and drained sample for 60 min reaction time was 23.99 g / 100 g of dry biomass, whereas the theoretical glucose yield for water (no ammonia) for 60 min reaction time was 10.07 g / 100 g of dry biomass. Theoretical glucose yield for water soaked and drained sample for 60 min reaction time was 10.91 g / 100 g of dry biomass. The results also indicated that pretreatment time and various combination mixtures were statistically significant at the 95% confidence interval for % glucose yield of pretreated energy cane bagasse. The pretreatment efficiency was also observed via increased porosity and fiber swelling of the treated energy cane fibers through Scanning Electron Microscopy (SEM). These results demonstrated that ultrasonic pretreatment along with NH4OH can be used as a potential pretreatment method for lignocellulosic biomass to produce biofuels.

Thesis (M. S.)--Texas A&M University, 2008. / "Major Subject: Biological and Agricultural Engineering" Title from author supplied metadata (automated record created on Oct. 13, 2008.) Vita. Abstract. Includes bibliographical references.

Thesis (M. S.)--Texas A&M University, 2008. / "Major Subject: Biological and Agricultural Engineering" Title from author supplied metadata (automated record created on Oct. 13, 2008.) Vita. Abstract. Includes bibliographical references.

Thesis (Ph. D.)--Texas A&M University, 2003. / "Major Subject: Biological and Agricultural Engineering" Title from author supplied metadata (automated record created on Feb. 17, 2005.) Vita. Abstract. Includes bibliographical references.

Thesis (Ph. D.)--Texas A & M University, 2004. / "Major Subject: Biological and Agricultural Engineering." Title from author supplied metadata (automated record created on Feb. 17, 2005.). Vita. Abstract. Includes bibliographical references.

Thesis (M. S.)--Texas A&M University, 2004 / "Major Subject: Biological and Agricultural Engineering" Title from author supplied metadata (automated record created on Feb. 17, 2005.) Vita. Abstract. Includes bibliographical references.

Thesis (M.S.)--Texas A & M University, 2004. / "Major Subject: Biological and Agricultural Engineering." Title from author supplied metadata (automated record created on Oct. 15, 2004.). Vita. Abstract. Includes bibliographical references.