Hood College Department of Chemistry and Physics
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Item Thiophene Hydrodesulfurization on High-Capacity Mesoporous Perovskite Oxide Catalysts(2025-04-23) Núñez, Melissa; Ashish Chakradhar; Hood College Department of Chemistry and Physics; Hood College Departmental HonorsHydrodesulfurization (HDS) is an essential industrial process used to remove sulfur from hydrocarbons, such as crude oil, to mitigate the harmful environmental and health effects associated with sulfur emissions. The presence of sulfur compounds, particularly in transportation fuels, can poison catalysts used in refining processes and contribute to the formation of sulfur dioxide, a greenhouse gas. As stricter environmental regulations on sulfur content in fuels emerge, the need for efficient, cost-effective, and sustainable catalysts for HDS has become increasingly critical. Thiophene, a sulfur-containing compound found in petroleum, is often used as a model molecule to study HDS reactions. This study focuses on comparing the performance of perovskite oxide catalysts like LaCoO3, LaNiO3, and LaFeO3 with the widely used CoMo catalyst. The research explores the role of metal composition, catalyst structure, and reaction mechanisms in influencing the efficiency of sulfur removal. By evaluating these materials, this study aims to identify potential alternative or supplementary catalysts for HDS that can improve sulfur conversion rates, enhance catalyst stability, and meet environmental goals. The findings contribute to advancing HDS technology, with a focus on optimizing catalyst design for future applications in cleaner fuel production.Item Gait Analysis of Healthy Subjects in Real-world Environments through Video Input(2023-04-28) Attota, Evangeline; Kambic, Robert; Lawrence, Dana; Krishnaswamy, Jennifer; Hood College Chemistry and Physics; Hood College Departmental HonorsGait, a person’s way of walking, can be negatively affected by neurological diseases such as Parkinson’s. When attempting to correct defects, it is useful for clinicians to create goals based on normal gait. However, data from the lab compared to data taken outside is hypothesized to create unrealistic targets due to the controlled nature of the lab. Most gait measurements are collected inside the lab because current methods of measuring gait are not convenient outside the lab. This research develops a versatile method of analyzing gait based on deep learning algorithms that require only video input. Using this method, the gait asymmetry in average populations both inside and outside the lab can be measured and compared, with the aim of establishing more relevant clinical goals. We found that in step length and stride time asymmetry, there was higher variance outside the lab compared to inside the lab. Stride time asymmetry also showed a higher average asymmetry outside the lab, though we did not see this in step length asymmetry. Finally, subjects tended to take larger steps inside the lab compared to outside.Item Thiophene Hydrodesulfurization Catalysis over Transition Metals Supported on Mesoporous MaterialsWilson, Lindsay; Chakradhar, Ashish; Department of Chemistry and Physics; Hood College Departmental HonorsHydrodesulfurization (HDS) is a commonly used industrial process for removing sulfur from fuel. Fuels containing sulfur are treated with hydrogen gas in the presence of a catalyst, producing sulfur-free hydrocarbons for cleaner fuel. In this study, the reactivity of several potential catalysts containing transition metals on mesoporous supports, such as 1% Zn and 10% Zn on SiO_(2 ), 0.5% Ni on SrTiO_(2 ), and 5% Co on CeO_(2 ), toward the hydrodesulfurization of thiophene were studied using a gas-chromatograph based mini flow reactor. Thiophene is used as the probe molecule because it is found in natural petroleum and is simple enough probe molecule to obtain mechanistic molecular-level information. The reactivity of thiophene on commercially available silica supported CoMo catalyst was studied and compared with the results of the catalysts of interest. Two main goals of this study were to identify a catalyst that could produce sulfur free hydrocarbons as or more efficiently than the commercial catalyst. Unfortunately, CoMo had the highest conversion rate with 35%; however, 5% Co on CeO_(2 )was not far behind at 22.3%. The 0.5% Ni on SrTiO_(2 )catalyst had a much lower conversion rate of 6.9%, and neither Zn on SiO_(2 )catalysts were successful in the hydrodesulfurization of thiophene. This research project on hydrodesulfurization will help in the current need for cleaner fuels with a new generation of catalysts with higher reactivity.Item Investigation of the Structure and Function of P-Rex2: Implications for a Molecular Mechanism of PTEN Inhibition(2017) Diethrich, Timothy; Ensel, Susan; Hood College Chemistry and Physics; Hood College Departmental HonorsItem Ultrafast Laser Spectroscopy to Study Photodynamics of Asymmetric HydrogenasesMeyers, Amber; Stromberg, Christopher; Heilweil, Edwin; Hood College Department of Chemistry and Physics; Hood College Chemistry ProgramItem Development of an Assay for Antimicrobial Susceptibility Testing of Coxiella burnetii(2019-04-29) Khan, Maisha; Hale, Martha; Department of Chemistry and Physics; BiochemistryCoxiella burnetii, a small Gram-negative bacterium, is the causative agent of Q fever, a zoonotic disease with initial flu-like symptoms that lead to both acute and chronic stages of infection. As with many obligate intracellular parasites, C. burnetii has been difficult to culture and therefore has been difficult to establish assays that examine a compound’s direct effect upon the bacterium. The development of an axenic medium for C. burnetii provided a method with which to culture the bacterium in liquid medium and thereby permitted our development of an assay for examining C. burnetii sensitivity to various anti-bacterial compounds. In order to establish the assay, the nonpathogenic C. burnetii Nine Mile Phase II Clone 4 (CBNMIIC4) strain was cultured (37°C) in acidified citrate cysteine medium (ACCM2) under hypoxic conditions. After 4 days in culture, the OD600 of the culture was adjusted to 0.10 (corresponding to approximately 6.8 x 108 bacteria per mL) and then added to wells in a 96-well plate containing dilutions of various anti-bacterial compounds. The plates were incubated (37°C) under hypobaric conditions for 5 days after which the OD600 was measured to determine whether the compounds affected CBMNIIC4 growth. Characterization of CBNMIIC4 growth was verified by measuring CBNMIIC4 genomic DNA and colony forming units in treatment cultures compared to the controls. The results of these studies provide a much-needed assay to assess the effects of anti-bacterial compounds upon C. burnetii growth.Item Targeted Mutagenesis of Human BRCA2 via Recombineering for Functional Evaluation of Unclassified Variants(2019-04-29) Riedel-Topper, Maximilian; Lawrence, Dana; Chemistry and Physics; Departmental HonorsBreast cancer is a significant area of research, as it is the most common type of cancer to affect women. BRCA2 is a cancer susceptibility gene that, when carrying a mutation, has a high chance of causing hereditary breast cancer, which affects entire families. Mutations to this gene can lead to the loss of its important DNA-repairing function, which leads to cancer susceptibility. Genetic testing is be a powerful tool in finding these mutations and can lead to counseling for affected families. However, there are many mutations with clinical impacts that are still unknown. Functional assays are used to determine the effect that mutations will have. In the work described in this paper, a library of BRCA2 variants was made for testing in a mouse embryonic stem cell-based functional assay. The mutations were created in bacterial artificial chromosomes containing the human BRCA2 gene via recombination-based genetic engineering inside Escherichia coli. In total, cell lines containing 31 variants of uncertain significance were successfully generated, and the mutant BRCA2 is ready for isolation and functional analysis via the mouse embryonic stem cell assay.