UTSA Student Works
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Browsing UTSA Student Works by Department "Chemistry"
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Item An Enhanced Avermectin Extraction Method for Characterization of Bovine Pharmacokinetics Utilizing Tandem Mass Spectrometry(UTSA Graduate School, 2024-04-02) Jellick, Greg; Lohmeyer, Kimberly; Ellis, Dee; Bach, StephanBabesia bigemina and B. bovis are protozoans spread amongst livestock by certain species of ticks, known collectively as cattle fever ticks (CFTs), and cause the chronic disease bovine babesiosis. Although eradicated from the US in 1940s, CFT and Babesia are endemic to Mexico, Central and South America. CFT continue to infiltrate the US by crossing the border on wildlife or stray livestock and infest cattle herds. Avermectins are a class of anti-tick drugs administered to cattle to prevent and control tick infestation. Texas A&M University in collaboration with the US Department of Agriculture (USDA) conducted a doramectin (DOR) dosing study to evaluate how a double dose of DOR might extend the window of protection versus a single dose. We developed and validated a sensitive liquid chromatography/ tandem mass spectrometry (LC-MS/MS) method for analysis of the study’s samples. Presented here are an enhanced analytical method for this lipophilic class of drugs, the DOR plasma concentrations from the study, and the relevant pharmacokinetic parameters.Item An STM Study of Nickel Carbide and Copper Carbide Surfaces(UTSA Graduate School, 2024-04-02) Sutherland, Kevin; Sanchez, Jennifer; Xu, FangTransition metal carbides and nitrides (TMCs and TMNs) have shown unique properties for strongly binding reaction intermediates and d-block transition metals and have been used as heterogeneous catalysts. Due to the predicted strong binding with metals, TMCs and TMNs are also very promising support for single atom catalysts (SACs), which possess high atomic efficiency and high catalytic performance compared to traditional catalysts yet face a common challenge of thermal instability. Elucidating the structures of TMCs and TMNs at an atomic level and the interactions between the surface and adsorbate is a crucial fundamental question to address. Herein, well-defined transition metal carbide and nitride films are prepared on Cu(111) and Ni(111) surfaces as model catalyst supports for SACs (Figure 2). The insights gained from the model catalyst surfaces will be used to promote the development of catalytic reactions, such as aqueous phase methanol reforming (APRM).Item Correlated Oxidative Stress and Mitochondrial Abnormalities in Aging are Discontinuous with Alzheimer’s Disease(Office of the Vice President for Research, 2018) Nguyen, Richard Q.; Bach, Stephan H.; Phelix, Clyde F.; Perry, GeorgeOxidative stress and mitochondrial damage precede Alzheimer’s disease (AD) hallmark pathologies, neurofibrillarytangles (NFT), and senile plaques.Mitochondria’s exact role in oxidation of pyruvate and NADH play a critical role in oxidative damage. We conducted this study to identify the relationship of oxidized RNA, 8--OHG biomarker, and mtDNA accumulation in AD and aging individuals. Abnormalities were examined by using densitometry of hippocampal pyramidal neurons: mtDNA accumulation as a marker of mitophagy and oxidative damage by 8-OHG. Among aging individuals, 8-OHG and mtDNA accumulation were highly correlated (R2=0.87,p=0.0007). While both 8-OHG and mtDNA were at higher levels in AD individuals, they were uncorrelated (R2=0.4418,p=0.07).In AD individuals, 8-OHG was inversely correlated with amyloid-β, while in aging, there was no significant correlation. These results suggest the discontinuity of similarities between aging and AD. These findings also indicate that the onset of AD is marked by a pleotrophic change in oxidative stress, one characterized by a change from mitochondria degeneration to amyloid-β independency.Item Explore the interaction of heterocyclic compounds against the SARS-CoV-2(2021-04-08) Dang, HangItem Imaging MS with MS(2021-04-08) Berlin, KristaItem Stem Cells used for Tissue Engineering of Articular Cartilage: Literature Review(UTSA Office of Undergraduate Research, 2022-12) Advano, Dhillon R.; Abu-Lail, Nehal I.Adult articular cartilage (AC) has a limited self-healing capacity. Cartilage defects lead to osteoarthritis (OA) characterized by severe pain and impaired mobility. Currently, there are no approved treatments for OA that successfully reverse or heal structural defects permanently. Although techniques such as microfracture, arthroplasty and subchondral drilling have been effective at treating small to intermediate sized AC defects over the short term, a long-term solution for OA is still necessary. In recent years, research has focused on tissue engineering of articular cartilage (TEAC) as a potential treatment option for OA. TEAC therapies utilizing chondrocytes such as autologous chondrocyte implantation (ACI) are promising but are limited by their complexity, high cost and inability to promote the formation of healthy hyaline AC. Due to the limitations of ACI, stem cells have been investigated as an alternative cell source for TEAC. To engineer AC, stem cells are allowed to differentiate on/in a scaffold in a bioreactor that controls chemical, physical and biological cues to support the chondrogenic potential of the stem cells. The use of stem cells provides numerous advantages as treatment costs can be lowered, the number of required surgeries can be reduced and high-quality AC can be formed. Mesenchymal stem cells (MSC) in particular are advantageous in that they are easily available and can be extracted from a diverse range of tissues including, bone marrow, adipose, and synovium. Each type of MSC have their own advantages and disadvantages but generally each of them possess high chondrogenic potential and immunosuppressive capacities. Induced pluripotent stem cells (iPSC) have also been recognized as a promising cell type for TEAC due to their unlimited proliferation and self-renewal capacities. Ultimately, each cell source has potential for use in TEAC therapies but further studies comparing cell sources are required before a gold standard can be determined. This review summarizes the pros and cons for potential use of each stem cell source in TEAC. The review is not meant to be comprehensive of the current literature.