LOUIS University of Alabama in Huntsville
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Testing structural model of TraT virulence factor encoded in antibiotic-resistance plasmids of uropathogens
No full textTraT is a multifunctional protein encoded by F-like plasmids that serves as a virulence factor in enteric bacteria. TraT protein confers benefits onto its cell, such as serum and macrophage resistance, resistance to bacteriophages, and the transfer of redundant plasmids through conjugation. Despite many roles and appearances in up to 80% of clinical antibiotic-resistant isolates of Escherichia coli, prior research has established little about TraT structure and how it relates to the protein’s many functions. This study aims to investigate the role of TraT in serum resistance by knocking out the traT gene via applying the CRISPR-Cas9 gene editing system. The study also aims to identify the possible involvement of amino acid residues of TraT that appear at the subunit interfaces in a structural model of this protein oligomer. This will be done by introducing mutations in these residues in the construct expressing recombinant TraT protein for in vitro analyses. The serum-killing assay demonstrated that TraT might not solely confer resistance to the serum complement, suggesting there might be other serum-resistance factors that work independently of TraT presence. Future work involves the structure analysis of altered TraT protein through X-ray crystallography, cryo-EM or size exclusion chromatography to analyze the oligomeric state of obtained in this thesis TraT variants
Nuclear fission rovers for Martian exploration
Get PDFA comprehensive analysis was performed on the impact of embedding a Kilopower-style fission reactor into a pressurized rover on architectural performance for a sample lunar, Mars opposition, and Mars conjunction mission. The high gamma ray flux necessitated the addition of substantial shielding for the crew. A single material shielding analysis using the Taylor formulation revealed that varying the distance between the crew and the reactor core from 3 m to 6 m reduced the required shielding thickness by 7%. Increasing the power output of the reactor from 3.4 kWe (comparable to radioisotope power capability) up to 10 kWe (Kilopower design limit) resulted in a 6% increase in shielding thickness. Implementing directional shielding principles based on crew position relative to the core reduced shielding mass by 19% and shutting the reactor down before exiting the pressurized rover allowed for an additional 65% shielding mass reduction. Reducing the size of the reactor core required a correspondingly larger battery, where a comparison between a 6.5 kWe reactor and a 10 kWe reactor resulted in a total mass difference of less than 2 kg despite a larger radiator that was required for the 10 kWe case. A literature review was conducted to study all adjacent systems to the fission rover concept and were found to be lacking in one or more areas addressed by the fission rover architecture. Key Performance Parameters were calculated and used to trade the fission rover architecture with NASA’s baseline architecture derived from the best available literature. The fission rover architecture outperformed the lunar and opposition Mars missions in three of the five parameters, while matching the performance of NASA’s baseline in the other two. For conjunction Mars mission, the fission rover architecture was found to outperform NASA’s baseline in three of the five parameters, matching NASA’s baseline for one parameter, but with a cost increase of about 15%
Growing Awareness About Environmental Conservation in the Huntsville Botanical Gardens
Get PDFhttps://louis.uah.edu/research-horizons/1356/thumbnail.jp
Special Effects via Volume Ray Casting CPU vs. GPU Performance
Get PDFhttps://louis.uah.edu/research-horizons/1359/thumbnail.jp
Gender Perceptions of Humanoid Robotics in a High-Stress Enviroment
Get PDFhttps://louis.uah.edu/research-horizons/1362/thumbnail.jp
Interactions of caffeine with anticancer drugs studied by nuclear magnetic resonance
Get PDFCaffeine can form stacking through pi-pi interactions with aromatic anticancer drugs. While caffeine can reduce the toxicity of the anticancer drugs, caffeine can also reduce the efficacy of the anticancer drugs. Aromatic anticancer drugs, such as daunorubicin and irinotecan, work by intercalating into DNA. When caffeine binds to an anticancer drug, the new complex formed cannot easily intercalate into DNA strands. Through Nuclear Magnetic Resonance (NMR) spectroscopy, chemical shift values for pure caffeine, daunorubicin, and irinotecan, as well as, caffeine mixed with daunorubicin and irinotecan were analyzed. Different concentrations for the pure compounds and the mixtures were analyzed by NMR. The diffusion coefficients for daunorubicin, irinotecan, caffeine, and the mixtures were determined using Diffusion Ordered Spectroscopy (DOSY). This study found caffeine caused changes in chemical shift and diffusion coefficients of daunorubicin and irinotecan when mixed with caffeine due to the binding of caffeine with the anticancer drug
Curation and analysis of AI ready environmental justice datasets : a proof-of-concept study
Get PDFEquity and Environmental Justice (EEJ) advocates for unbiased distribution of environmental impacts across communities, regardless of social and economic characteristics. After extreme events like natural disasters, EEJ gains importance due to evident disparities in impact among communities. Addressing these injustices requires comprehensive datasets and analytical methods for quantification and resolution. While AI and advanced data analysis offer promising solutions, creating AI-ready EEJ datasets is challenging due to heterogeneity in the data surrounding EEJ. In this work, we focus on curating novel datasets for EEJ targeting a few recent extreme events - Maui Wildfire, Hurricane Harvey, and Hurricane Ida. We demonstrate the utility of the datasets using preliminary analysis with machine learning and AI enabled methods. Succinctly, we created masks to identify EEJ issues and generated nuanced insights employing machine learning, image processing and statistical methods. This study has the potential to empower authorities in data-driven policy-making, disaster management, and resource allocation, addressing the actual needs of affected communities
Improvements of Radial Stretch Tester for Mechanical Characterization of Flexible Electronics
Get PDFUnsteady flow characteristics of a normal shock wave and associated lambda foot
Get PDFShock wave interactions are important in a variety of engineering applications, ranging from gas turbines to rocket nozzles. There is much discussion regarding the sources of unsteadiness related to unsteady shock wave structure. This thesis investigates related interactions through spectral analysis of shock wave tracked positions, and instantaneous surface static pressure, temperature, and heat flux. A shadowgraph system for implementing shock wave tracking analysis is employed within a supersonic test section with an inlet freestream Mach number of 1.54. Unsteady surface static pressure and temperature variations are measured at streamwise locations along the bottom wall. Unsteady temperature data are used to determine surface heat flux variations. Pressure, temperature, and heat flux variations are correlated to the position of the normal shock wave through magnitude squared coherence and time lag. Data show complex physical variations that change as frequency, inlet turbulence intensity, and location relative to the shock wave are altered