Institutional Repository

The University of Houston Institutional Repository (UHIR) collects, preserves and distributes scholarly output and creative works produced by the University of Houston community. UHIR provides free and open online access to the university’s research and scholarship, including electronic theses and dissertations.


Recent Submissions

Using evolution and development of Antarctic fishes to understand adaptation to climate changes past and present
(2024-02-28) Daane, Jaccob
Climate change is expected to disrupt weather patterns and alter habitat boundaries, exerting pressure on species to either migrate or adapt to their changing environments. Over the past 30 million years, Antarctic notothenioid fishes have diversified from a common ancestor into numerous descendant species following prolonged global cooling. This diversification offers an opportunity to retrospectively analyze their adaptive responses to past climate change events. Moreover, these fish, known for their adaptation to frigid and thermally stable waters, are highly susceptible to ocean warming, making them valuable sentinel species in the present era. Here, I will discuss comparative genomic approaches to reconstruct patterns of trait evolution in relation to historical climate change events. Additionally, I will discuss initial efforts to model the impact of climate change on embryonic development, a vulnerable stage in fish thermal adaptation. These findings establish a foundation for predicting species adaptability in the modern era.
Enhanced Volts-per-Hertz Sensorless Starting of Permanent Magnet Motor with Heavy Loads in Long-Cable Subsea Applications
(2024-02-19) Singh, Virendra; Selvaraj, Goutham; Rajashekara, Kaushik
Permanent magnet (PM) motors are gaining prominence in subsea applications such as drilling, pumping, and boosting for oil and natural gas extraction. These motors are gradually replacing traditional induction motors. However, starting and operating PM motors at low speeds under heavy loads poses significant challenges. This is because of unknown initial rotor positions and resistive voltage drops due to the presence of a sinewave filter, transformer, and long cable. An unknown rotor position may result in temporary reverse speed, which may cause a loss of synchronism; therefore, initial rotor position estimation is preferable. Additionally, addressing the voltage drop issue requires careful voltage compensation to avoid transformer core saturation. In this paper, an enhanced V/Hz starting of a PM motor is proposed with initial position detection (IPD) and voltage compensation to start the motor reliably with a heavy load. The proposed control method is verified with controller hardware in the loop (C-HIL) real-time simulation using a Typhoon HIL-604 emulator and a Texas Instruments TMS320F28335 digital signal processor (DSP) control card.
Attachment-Based Mentalization Profiles of Iranian Children: A Mixed-Method Approach
(2024-02-17) Zandpour, Masoumeh; Lind, Majse; Sharp, Carla; Hasani, Jafar; Bagheri Sheykhangafshe, Farzin; Borelli, Jessica L.
Mentalization, operationalized as reflective functioning (RF), is the ability to understand one’s own and another’s mental world implicitly or explicitly. RF is a newly discovered research field in Iran and is largely under-studied in Eastern cultures in general, underscoring the high need for cross-cultural studies in this field of research. A qualitative method was used to examine the ability to understand, process, and respond to high-arousal attachment situations in typical and clinical populations of Iranian children recruited from a Tehran primary school. A well-known semi-structured interview commonly used to assess RF in children was used to collect data. Required information on internalizing and externalizing symptoms, demographic information, and all formal diagnoses of children were collected by parents. The results indicated the identification of four different profiles of RF in children, one of which was adaptive, while the other three were maladaptive. Also, the results showed that typically developing children and those having a high social and economic status (SES) were characterized as having a more adaptive profile of RF, while children from the clinical population and those with a low SES reported a more maladaptive profile (passive mentalizing, helpless mentalizing, narcissistic mentalizing) of RF. The present study is an important step in increasing our understanding of the development of mentalization in children and has significant educational and clinical implications.
The Interplay between Neurotransmitters and Calcium Dynamics in Retinal Synapses during Development, Health, and Disease
(2024-02-13) Boff, Johane M.; Shrestha, Abhishek P.; Madireddy, Saivikram; Viswaprakash, Nilmini; Della Santina, Luca; Vaithianathan, Thirumalini
The intricate functionality of the vertebrate retina relies on the interplay between neurotransmitter activity and calcium (Ca2+) dynamics, offering important insights into developmental processes, physiological functioning, and disease progression. Neurotransmitters orchestrate cellular processes to shape the behavior of the retina under diverse circumstances. Despite research to elucidate the roles of individual neurotransmitters in the visual system, there remains a gap in our understanding of the holistic integration of their interplay with Ca2+ dynamics in the broader context of neuronal development, health, and disease. To address this gap, the present review explores the mechanisms used by the neurotransmitters glutamate, gamma-aminobutyric acid (GABA), glycine, dopamine, and acetylcholine (ACh) and their interplay with Ca2+ dynamics. This conceptual outline is intended to inform and guide future research, underpinning novel therapeutic avenues for retinal-associated disorders.
Duplex Vertical-Flow Rapid Tests for Point-of-Care Detection of Anti-dsDNA and Anti-Nuclear Autoantibodies
(2024-02-12) Lei, Rongwei; Arain, Hufsa; Wang, David; Arunachalam, Janani; Saxena, Ramesh; Mohan, Chandra
The goal of this study is to develop a rapid diagnostic test for rheumatic disease and systemic lupus erythematosus (SLE) screening. A novel rapid vertical flow assay (VFA) was engineered and used to assay anti-nuclear (ANA) and anti-dsDNA (αDNA) autoantibodies from systemic lupus erythematosus (SLE) patients and healthy controls (HCs). Observer scores and absolute signal intensities from the VFA were validated via ELISA. The rapid point-of-care VFA test that was engineered demonstrated a limit of detection of 0.5 IU/mL for ANA and αDNA autoantibodies in human plasma with an inter-operator CV of 19% for ANA and 12% for αDNA. Storage stability was verified over a three-month period. When testing anti-dsDNA and ANA levels in SLE and HC serum samples, the duplex VFA revealed 95% sensitivity, 72% specificity and an 84% ROC AUC value in discriminating disease groups, comparable to the gold standard, ELISA. The rapid αDNA/ANA duplex VFA can potentially be used in primary care clinics for evaluating patients or at-risk subjects for rheumatic diseases and for planning follow-up testing. Given its low cost, ease, and rapid turnaround, it can also be used to assess SLE prevalence estimates.