Theses and Dissertations
This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students.
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- All Subjects: Fuel production
- All Subjects: Infant
The incidence of childhood obesity has become increasingly prevalent in the United States in recent years. The development of obesity at any age, but especially in adolescence, can have lasting negative effects in the form of cardiometabolic disease, increased incurred healthcare costs, and potential negative effects on quality of life. In recent years, a rising trend of obesity, in both adults and adolescents, has been observed in lower income and ethnic groups. Increased adiposity can be influenced by modifiable factors -(physical activity, caloric intake, or sleep) or by non-modifiable factors (ethnicity, genetic predispositions, and socioeconomic status). The influence of these factors can be observed in individuals of all ages, including infants. A common indicator of the development of childhood obesity is rapid weight gain (RWG) within an infant’s first year of life. The composition of the gut microbiome can act as a predictor for RWG and the development of childhood obesity. Infants are exposed to an immense microbial load when they are born and their gut microbiome is continually diversified through their method of feeding and the subsequent introduction to solid foods. While currently understudied, it is understood that cultural and socioeconomic factors influence the development of the gut microbiome, which is further explored in this analysis. The DNA from 51 fecal samples from infants ranging from 3 weeks to 12 months in age was extracted and sequenced using next-generation sequencing, and the resulting sequences were analyzed using QIIME 2. Results from alpha-diversity and beta-diversity metrics showed significant differences in the gut microbiome of infants when comparing groups based on baby race/ethnicity, household income, and mom’s education. These findings suggest the importance of sociodemographic characteristics in shaping the gut microbiome and suggest the importance of future studies including diverse populations in gut microbiome work.
sustainable, carbon neutral energy source to curb the reliance on fossil fuel combustion as the primary source of energy. To overcome this challenge, research efforts have turned to biology for inspiration, as nature is adept at inter-converting low molecular weight precursors into complex molecules. A number of inorganic catalysts have been reported that mimic the active sites of energy-relevant enzymes such as hydrogenases and carbon monoxide dehydrogenase. However, these inorganic models fail to achieve the high activity of the enzymes, which function in aqueous systems, as they lack the critical secondary-shell interactions that enable the active site of enzymes to outperform their organometallic counterparts.
To address these challenges, my work utilizes bio-hybrid systems in which artificial proteins are used to modulate the properties of organometallic catalysts. This approach couples the diversity of organometallic function with the robust nature of protein biochemistry, aiming to utilize the protein scaffold to not only enhance rates of reaction, but also to control catalytic cycles and reaction outcomes. To this end, I have used chemical biology techniques to modify natural protein structures and augment the H2 producing ability of a cobalt-catalyst by a factor of five through simple mutagenesis. Concurrently I have designed and characterized a de novo peptide that incorporates various iron sulfur clusters at discrete distances from one another, facilitating electron transfer between the two. Finally, using computational methodologies I have engineered proteins to alter the specificity of a CO2 reduction reaction. The proteins systems developed herein allow for study of protein secondary-shell interactions during catalysis, and enable structure-function relationships to be built. The complete system will be interfaced with a solar fuel cell, accepting electrons from a photosensitized dye and storing energy in chemical bonds, such as H2 or methanol.