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Humanization of yeast for functional expression and screening of G protein-coupled receptors
Get PDFThe yeast Saccharomyces cerevisiae is a well-characterized and genetically tractable eukaryote. While humans and yeast shared their last common ancestor over 1 billion years ago, the species have several thousand genes in common. Yeast provides a powerful platform to study human proteins and systems, including the pharmacologically important cell surface G protein-coupled receptors (GPCRs). In this dissertation I first present a review of GPCR and signal transduction engineering strategies, and then outline membrane engineering work to improve the function of human GPCRs in yeast. I follow with a description of cannabinoid receptor expression and compound screening, and close with the development and utilization of a platform to screen peptide libraries against opioid receptors for agonist identification.Microbiolog
Improving flood and pollution management under uncertainty through real-time data assimilation and model predictive control of stormwater basins
Get PDFSmart stormwater systems equipped with real-time controls are transforming urban drainage management by enhancing the flood control and water treatment potential of previously static infrastructure. Real-time control of detention basins, for instance, has been shown to improve contaminant removal by increasing hydraulic retention times while also reducing downstream flood risk. However, to date, few studies have explored optimal real-time control strategies for achieving both water quality and flood control targets. This study advances a new model predictive control (MPC) algorithm for stormwater detention ponds that determines the outlet valve control schedule needed to maximize pollutant removal and minimize flooding using forecasts of the incoming pollutograph and hydrograph. We illustrate that, compared to rule-based controls, MPC more effectively prevents overflows, reduces peak discharges, improves water quality, and adapts to changing hydrologic inputs. Moreover, when paired with an online data assimilation scheme based on Extended Kalman Filtering (EKF), we find that MPC is robust to uncertainty in both pollutograph forecasts and water quality measurements. By providing an integrated control strategy that optimizes both water quality and quantity goals while remaining robust to uncertainty in hydrologic and pollutant dynamics, our study paves the way for real-world smart stormwater systems that will achieve improved flood and nonpoint source pollution management.Civil, Architectural, and Environmental Engineerin
Processing and design of additively manufactured carbon fiber thermoplastic composites
No full textThermoplastic composites (TPCs) exhibit exceptional thermo-mechanical properties and are compatible with several additive manufacturing (AM) technologies. These attributes pave the way for new opportunities in creating lightweight, high-performance composite structures across various industries. In particular, carbon fiber reinforced TPCs based on semi-crystalline polyaryletherketone (PAEK) matrices are gaining popularity in the aerospace, marine, renewable energy, and medical industries. This dissertation investigates the processing and design of these AM composites. Three different AM processes are studied here, namely fused filament fabrication (FFF), selective laser sintering (SLS), and laser-assisted automated fiber placement (AFP). The proposed research covers three major areas related to AM of carbon fiber reinforced PAEKs. First, it investigates the influence of processing and FFF or SLS methods on the structure, morphology, and properties of the resulting coupons from a materials science perspective. Second, it explores the manufacturability and validation of topology and fiber path optimized TPC structures from a design standpoint. Third, the research delves into the processing and failure mechanics of in-situ consolidated AFP TPC (ICAT) parts. With these insights into materials science, manufacturing, and design, this dissertation will improve our understanding of the mechanical performance of AM TPCs.Mechanical Engineerin
Nonproliferation detection technology graduate course framework utilizing nontraditional learning
Get PDFThis dissertation presents the development and implementation of a nontraditional learning (NTL) approach for a course on nonproliferation detection technology. The motivation behind this work is to innovate technical education methods and prepare students for multidisciplinary challenges in the Nuclear Security Enterprise (NSE). The primary objective was to create a course framework that emphasizes methods that aid in the development of critical thinking, communication, and collaboration skills which are essential for success in nuclear security careers. This framework is comprised of three categories of NTL methods: pre-recorded lectures, just-in-time learning, and discussions on scholarly work. Seven PowerPoint presentations were developed, comprised of 267 slides that could be used for pre-recorded or in person classes. Two just-in-time simulations, with sixty-three pages of background, resources, simulation directions, and grading criteria were created. Resources for scholarly works as well as suggestions for assignments, student projects, and exams were provided. In addition to a NTL flexible course framework, a three course pilot was performed. Student feedback from a voluntary online survey and phone interview at the end of the semester provided insights into the effectiveness and suitability of NTL approaches. The survey and phone interview results highlight the perceived benefits and disadvantages of NTL methods. The students were asked to indicate which type of learning better achieved various learning objectives and were nearly split between NTL, 39% of responses, and traditional learning, 42% of responses. No preference represented 19% of responses. Phone interviews reaffirmed the conclusion that students would prefer a ~50% split between traditional and NTL methods. The majority of students stated that collaboration with their peers is important to their learning process and they are more likely to retain information through hands on-experiences or equally from hands-on experiences or theoretical concepts and lectures. Two students stated that exposure to NTL influenced their interest in pursuing a profession or additional courses in nuclear security. This dissertation contributes to the ongoing discourse on innovative pedagogical practices in technical education and underscores the importance of preparing students for the complexities of nuclear security challenges. Future work includes refining the course framework based on student feedback, exploring innovative assessment methods, and investigating the long-term impact of NTL approaches on student performance and career readiness in the NSE.Mechanical Engineerin
A New School Discipline Fulcrum: Identifying and Rectifying
Get PDFSchool officials continue to utilize punishment despite the conflict between these means and established best practice for children and youth (APA, 2008). Nearly 50 years of research echoes what many impacted already know: the way K-12 education “does discipline” is ineffective and counterproductive succeeding only in pushing out students of color and students experiencing poverty (Edelman et al., 1974, 1975; Leung-Gagné et al, 2022; Williams, 2024). And, no matter how you cut it, exclusionary discipline in its many forms continues to disproportionately impact the lives of Black children, adolescents, and family members who bear myriad associated costs (Bell, 2021; Darling-Hammond & Ho, 2024). These ongoing patterns are alarming, as countless studies have concluded that exclusionary discipline (i.e., suspensions, corporal punishment, and expulsions), do not promote pro-social behavior and adversely impact youth outcomes (Welsh & Little, 2018). The premise that exclusionary school discipline has rested upon – that imposing penalty or sanction in some way benefits students or schools – has long been faulty. It is time to put this outdated way of thinking to rest. Schools are in need of a paradigm for “doing discipline,” essentially what is needed is a new school discipline fulcrum, one resting upon different assumptions, namely: (1) continued efforts to identify patterns (and in an era where race-consciousness is increasingly under legal and political suppression the need for continued, explicit, identification of race and gender patterns) and (2) the importance of rectifying, or making right identified forms of harms, disparities, and the dispossession of generational inequalities stemming from unequal discipline (Conwell, 2016). The authors featured in this special issue offer insights on both fronts, identifying school discipline concerns in new areas and offering promising frameworks for rectifying the current pushout fulcrum, including addressing the anti-Black roots underlying much of schooling.Educatio
Design and optimization of magnetic components for high-frequency power electronics
No full textMagnetic components - inductors and transformers - are utilized in virtually every power converter for their energy storage and galvanic isolation capabilities. Despite their wide adoption and usefulness, these components are difficult and unintuitive to design, especially for operation at high frequencies. As it becomes more common for power converters to operate in the MHz regime, motivated by the ability to miniaturize components and the availability of high performance, wide bandgap power semiconductors, it is important to address the potential bottleneck posed by lossy high-frequency magnetic components. This work directly deals with the design, characterization, and optimization of such components. It also includes the design of a differential power processing system enabled by a HF planar transformer.Electrical and Computer Engineerin
Service integration planning assessment for Capital Metropolitan Transportation Authority and Project Connect in Austin, TX
Get PDFDuring the summer of 2023, I had the unique opportunity work as a service integration planning intern with the Capital Metropolitan Transportation Authority (CapMetro), the city of Austin’s transportation agency, where I investigated and analyzed the different obstacles the agency faces in successfully integrating its existing bus network with the future light rail transit (LRT) line that is scheduled to be built as part of Project Connect. As the LRT portion of Project Connect begins to take shape, it is imperative that that Austin’s existing bus network is adequately integrated with the light rail service in order to ensure that existing and potentially
new public transit users are enticed to using the new system, and that those who use intend to use both methods of transport will be able to make a smooth transition between the bus and light rail and vice versa. This process of service integration entails a variety of both qualitative and quantitative changes that primarily deal with user experience of public transportation, including the quality of the ride on the bus, how long the trip will take, and the physical transition from one mode of transportation to another. The research methodology in this report – a two-step process consisting of a desktop-based assessment of various ridership and service quality statistics and an in-person survey of station areas to analyze various design elements and amenities – is an analysis framework of my creation. My findings reveal that CapMetro will have an easier time integrating both modes of transit along station areas that are more densely populated and economically developed. For integration to be successful across the system, CapMetro should make necessary improvements to its bus stops and service, and work with the City of Austin to upgrade nearby sidewalks and roads. The report I prepared for CapMetro last summer and the additional research I have completed for this report will hopefully provide valuable insight to the agency as it progresses with Project Connect. Likewise, I hope this report could serve as a model for transportation agencies in other cities embarking on similar projects and exploring how they can better integrate multiple modes of transportation.Community and Regional Plannin
Functional organic materials for directed self-assembly of silicon-containing block copolymers
Get PDFThe invention of the integrated circuit started a race to shrink the size of transistors and other electronic components that has lasted for decades and produced ever more efficient and cheaper electronic devices. This competition became the basis of the famous Moore’s law. One of the most important technologies that enables the realization of the Moore’s law is photolithography. This is the process that controls the dimensions of electronic components of a device. As optical lithographic techniques improved, the number of transistors in a single computer chip increased exponentially over time. The development of new photolithography techniques using shorter wavelength light, bigger lenses, better resists, etc. enabled this remarkable evolution. However, the state-of-the-art in photolithography, extreme ultraviolet (EUV) lithography using 13.5 nm light faces many challenges and is being continuously but very slowly developed. Alternative pathways to smaller features have been investigated that can achieve resolution beyond that of a conventional photolithography. Among these techniques, directed self-assembly (DSA) is one of the most promising nanofabrication strategies. In DSA, BCP thin films are self-assembled into ordered microdomains to produce the nanoscale patterns required to manufacture microelectronics. Silicon-containing BCPs with high interaction parameters (χ) enable patterning of lines-and-spaces with critical dimensions as small as 5 nm and such patterns have been successfully transferred into a substrate. DSA divides the pitch of an underlying prepattern, which reduces the resolution requirement of the lithography steps required to create high-resolution patterns. However, there are still ongoing challenges that must be met for DSA. These include BCP synthesis, interfacial engineering, defect annihilation, etc.
The work reported in this dissertation was focused on functional organic materials that enable DSA of silicon-containing BCPs. Chapter 1 provides an overview of lithography for the generation of microelectronic devices. Chapter 2 describes work on silicon-containing BCPs for lithography and the challenges related to orienting and aligning these materials. Chapter 3 describes the characterization and control of high-χ BCPs with remarkably high Tg. Chapter 4 describes efforts directed toward defect annihilation in DSA. Finally, Chapter 5 reports a new alignment strategy for high-χ BCPs based on the conventional photolithography, that enables more than ten-fold multiplication of guideline pitch.Chemical Engineerin
Texas Metropolitan Blueprint: A Five-Year Policy Agenda for Action
Get PDFAn actionable five-year plan to ensure the continuing prosperity and growth of Texas’s communities, the Texas Metropolitan Blueprint utilizes a comprehensive, cross-sector approach to align policy and action at both state and local levels.
Developed via a collaboration among the LBJ School of Public Affairs Urban Lab at The University of Texas at Austin, the George W. Bush Institute-SMU Economic Growth Initiative, and the Hobby School of Public Affairs at the University of Houston, the Blueprint draws on the insights of more than 175 business, government, and nonprofit leaders, representing Democratic, Republican, and nonpartisan perspectives.Texas’s 26 metropolitan areas, home to 90% of its population, are the engines of its economic growth. The Texas Metropolitan Blueprint outlines an actionable five-year plan to ensure their long-term prosperity and competitiveness.LBJ School of Public Affairs Urban Lab at The University of Texas at Austin, the George W. Bush Institute-SMU Economic Growth Initiative, and the Hobby School of Public Affairs at the University of HoustonLBJ School of Public Affair
Environmental sensing and response of conserved RNA-processing machines to specific external chemical cues
Get PDFMolecular mechanisms involved in sensing and responding to changes in environmental conditions are of high interest in the field of molecular biology and biochemistry because of the immediate cascade of events and macromolecular interactions that occur in a relatively short time frame to provoke a physiological response. RNA-processing molecular machines are important players in the physiological response to environmental stress; however, relatively little is known about the specificity of their RNA substrate recognition and/or the ability for other chemical substrates to influence their activity. The research presented herein describes features of two highly relevant models to investigate substrate specificity and/or interactions with regulatory molecules: polynucleotide phosphorylase and the ribosome. Both of these machines are multi-subunit and homologs retain similar functions in all three domains of life. The ribosome is the translational machinery of the cell, whose primary function is to translate the genetic code from mRNA to protein; however, it also maintains the capacity to respond to small molecule inducers and regulatory elements to influence expression of nearby genes. Polynucleotide phosphorylase (PNPase) is a homotrimeric protein whose primary function is to degrade and recycle mRNA; yet it also plays an important role in RNA quality control by sequestering oxidatively damaged RNAs. While much is known about the primary functions of these molecular machines, the bases for their selectivity and recognition of environmental cues that induce these alternative functions have been less explored. In Chapter 1, I describe my work to elucidate the influence of cellular factors and metabolites on a coupled transcription-translation system, the tna operon. The operon is a well-characterized negative feedback loop regulating tryptophan breakdown in the presence of excess nutrients in the environment. While much effort has been made to characterize the system’s response to tryptophan, a systematic characterization of operon induction by the full panel of naturally-occurring amino acids has yet to be performed. Based on this approach, I discovered that L-cysteine can also induce the tna operon along with a suite of other amino acids that are influenced by factors involved in coupled transcription-translation. This work provides novel insight on bacterial gene regulation dynamics and provides a strategy to reduce cross-talk in engineered systems that utilize the tna operon. In Chapter 2, I explore how PNPase differentially detects and degrades modified RNA bases harbored on RNA oligonucleotides. Curiously, the chemical modifications influence the fate of RNA processing by this enzyme. I show that the enzyme demonstrates sequence specificity and that, while one RNA modification of guanine (8-oxoguanine) disables degradation, processing of another modification (1-methylguanine) enhances degradation relative to its unmodified counterpart. The biological implications of selective degradation by this enzyme raises new questions about its role in transcriptome maintenance and its influence on cellular metabolism. A more complete understanding of the full breadth of these multifunctional complexes may allow control of traditionally intractable systems or provide new targets for drug design and development by novel mechanisms.Biochemistr