Postdoctoral Appreciation Week Poster Presentations 2023

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    UTSA Postdoc Appreciation Week Research Symposium Booklet
    (UTSA Office of Postdoctoral Affairs, 2023-09-22) UTSA Office of Postdoctoral Affairs
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    Design Requirements for Mechanically Spliced High-Strength Reinforcing Bars in Hinge Regions
    (2023-09-22) Abdullah, Wyra; Ghannoum, Wassim
    The application of mechanically spliced HSRBs is restricted in the hinge region of the concrete shear walls due to the absence of experimental validation. For this reason, this paper comprises testing of four full-scale shear walls. The control wall features HSRBs exclusively at the hinge region, while the remaining walls incorporate couplers of varying lengths, ranging from 3 inches to 14 inches, at their respective hinge regions. The walls will be tested under cyclic loading tests to assess the structural response, deformability, energy dissipation capacity, and failure modes. The walls are 16 feet high, 7 feet long, and 16 inches thick. The walls have a foundation to support and a top beam as a point of the application of loads. The walls will be tested under cyclic load using two 220 kip actuator on a reaction wall. The results of the experimental programm will be used to establish a guideline that covers aspects such as coupler type, concrete cover requirements, detailing at spliced regions, and anchorage lengths to ensure robust performance and compatibility with existing design codes and standards.
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    Comparative genomics reveals pathogen-and symbiont specific genes in Francisella and Coxiella
    (2023-09-22) Kolo, Agatha; Raghavan, Rahul
    Ticks are vectors of human and animal pathogens. Additionally, ticks harbor endosymbionts and other commensal bacteria. Coxiella and Francisella endosymbionts are tick-associated bacteria closely related to human pathogens Coxiella burnetii, the agent of Q fever, and Francisella tularensis, which causes tularemia. Prior studies showed genomes of endosymbionts encode genes for the synthesis of B vitamins and cofactors but have lost virulence-related genes. The aim of this study was to compare the genes present in pathogens and endosymbionts to identify metabolic pathways that have been differentially retained between the two lineages. The genome portal BioCyc was used to analyze the genomes of Francisella endosymbionts in Ornithodoros moubata and Argas arbereus ticks, pathogens F. tularensis subsp. tularensis and F. tularensis subsp. novicida, Coxiella endosymbiont in Rhipicephalus microplus, human pathogen C. burnetii RSA 493 Nine Mile phase I and laboratory strain C. burnetii RSA 439 Nine Mile Phase II. Analysis showed that endosymbionts possess pathways for the biosynthesis of amino acids, transporters of inorganic ions, LoIA-lipoprotein complex and Lipopolysaccharide (LPS). Some genes for the transport of LPS a major structural unit of gram-negative bacteria were notably absent in the genomes of pathogens. Metabolic processes absent from tick symbionts but present in pathogens include pathways for the metabolism of 2"-deoxycytidine, thymidine, inorganic nutrients, pyruvate and glucose oxidation. Additionally, virulence genes for outer membrane and periplasmic proteins were absent in symbiont genomes. This knowledge from the biochemical processes in endosymbionts could be useful in designing new approaches towards the control of ticks and tick-borne diseases.
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    Quantifying the Effects of Seismic Loading History on the Collapse Behavior of Concrete Columns
    (2023-09-22) Khedmatgozar Dolati, Seyed Sasan; Matamoros, Adolfo; Ghannoum, Wassim
    The current assessment methods to retrofit vulnerable concrete buildings in the US [ASCE 41-17, ACI 369.1-19] produce relatively conservative deformation capacities at the loss of lateral and axial strengths. Such conservatism hinders region-wide efforts to retrofit deficient buildings due to high costs. To improve the accuracy and reliability of structural assessment, continuum finite element models were calibrated to experimental tests for over twenty columns. Calibrated column models were then subjected to a series of loading protocols, including monotonic pushover and non-symmetric ratcheting protocols. The effects of the lateral loading protocols on damage progression, strength, and deformation capacities are discussed in these columns.