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Charge-Modulated Dynamics and Stimulus Response in Polyelectrolyte Solutions and Brushes
No full textPolyelectrolytes offer enhanced properties compared to their neutral counterparts due to intra- and interchain interactions between charged monomers. These interactions can be tuned through the charged monomer fraction and by modulating environmental conditions such as solution pH and ionic strength. However, how these factors influence the dynamics of polyelectrolyte solutions and brushes remains incompletely understood. In solutions, microrheology has become an indispensable tool for measuring macromolecular dynamics, yet its ability to characterize polymer behavior across spatiotemporal scales, varying among polymers and concentration regimes, is limited by the selection of probe morphologies and sizes. Here, we introduce semiflexible M13 phage as a powerful microrheological probe able to circumvent these constraints and robustly capture the dynamics of polymeric solutions across decades of concentrations, sizes, and ionic conditions. We show that phage mobility is directly coupled to the relaxation dynamics of polystyrene sulfonate, DNA, and their composites, spanning semidilute to entangled regimes and covering four orders of magnitude in ionic strength. Using this approach, we reveal key differences in the dynamics of synthetic and natural polyelectrolytes and demonstrate the potential of phage probes to elucidate complex relaxation processes. Extending our focus to weakly charged polyelectrolyte brushes, we systematically varied the fraction of ionizable monomers and studied their swelling behavior in response to changes in pH and ionic strength. Using in situ ellipsometry, streaming zeta potential, and atomic force microscopy, we reveal a strong correlation between the fraction of ionizable monomers and the pH-responsive swelling of the brushes, with significant hysteresis observed during pH cycling in the intermediate pH range, which we attribute to a hydrophobic periphery mechanism. We also uncover a salt-dependent extent of hysteresis, highlighting the interplay between electrostatic interactions and ionic screening in determining brush conformation. Together, these studies provide new insight into charge-dependent dynamics and stimulus-responsive behavior in polyelectrolyte systems
Modifications Based on Cognitive Interviews to the Spanish-Language Food Security Survey Module (S-FSSM)
No full textBackground: High rates of food insecurity are observed among Hispanic immigrant parents, with 63% having low English proficiency. Traditionally, Spanish-speaking immigrant parents have been excluded from food insecurity survey development. Sampling on Spanish-speaking immigrant parents, we conducted two rounds of cognitive interviews (CI) to gain perspective on how they conceptualized food insecurity experiences using the 18-item Food Security Survey Module (S-FSSM). Aims: To describe participants' insights on the relevancy and interpretation of the S-FSSM and how this information led researchers to revise the instrument. Methods: Data collection occurred at a community center. The interviewer read each S-FSSM item aloud and asked the participant to respond to several cognitive probes. Using conventional content analysis, two junior-level researchers independently reviewed interview transcripts, and then developed a consensus statement regarding changes needed. They, along with two senior-level researchers, reviewed the data and revised the survey based on participants' feedback. Results: 19 CI interviews were conducted (1st round, n=9; 2nd round, n=10), with mothers (average age 35). Primarily having less than a high school education (53% and unemployed (84%). In the 1st round of CI, participants felt several items were redundant; researchers made revisions that included deleting 3 items and combining items to reduce redundancy. Only 2 items from the original S-FSSM were included in the revised 16-item scale. In the 2nd round of CI, less revisions occurred including wording modifications and the addition of an item, resulting in 17-items. Conclusions: Revisions to the existing S-FSSM were needed to enhance relevancy for Spanish-speaking immigrant parents. [This project was completed with contributions from Anairany Zapata from Cizik School of Nursing at UTHealth Houston, and Rickelle Richards from Brigham Young University.]Health and Human Performance, Department ofHonors Colleg
Sustainable Self-Compacting Concrete with Recycled Aggregates, Ground Granulated Blast Slag, and Limestone Filler: A Technical and Environmental Assessment
No full textThis study investigates the use of demolition waste as recycled coarse aggregates (RCAs) to replace natural coarse aggregates (NCAs), and the use of ground granulated blast slag (GGBS) and limestone filler (LF) as a supplementary cementitious material, in self-compacting concrete (SCC), with proportions of 150 kg/m<sup>3</sup> for GGBS and 180 kg/m<sup>3</sup> for LF. Various SCC mixtures were prepared with RCA proportions of 0, 25, 50, 75, and 100%, while maintaining fixed dosages of LF and GGBS. Initially, RCA was incorporated in a dry state, followed by a water dosage adjustment for mixtures containing 100% RCA, equivalent to 20 min of RCA absorption. The experimental investigation evaluated the evolution of flow properties through tests such as slump flow, flow time (T500), L-box, sieve stability, fresh density, and air content. The static yield stress and plastic viscosity were also calculated using mathematical models. Additionally, hardened properties, including short-term and long-term compressive strength and capillary water absorption, were assessed. An environmental impact analysis of using demolition waste was conducted, revealing that a total NCA replacement with RCA is viable for both fresh and hardened states, provided that the RCA water absorption is managed and a reactive mineral additive is incorporated. For a 50% replacement of natural aggregates with recycled aggregates, this approach significantly reduces environmental impacts, lowering fossil fuel consumption by up to 35% and greenhouse gas emissions by up to 32%
The Role of Momentary Experiential Avoidance in the Relation Between Daily Ethnic Discrimination Experiences and Hazardous Drinking Outcomes Among Clinically Anxious Latinx Adults
No full textLatinx persons experience disparities as it relates to alcohol use and clinical anxiety. Although ethnic/racial (hereafter ethnic) discrimination has often been linked to poor behavioral health among Latinx persons and other groups, little work has explored mediational processes linking this social determinant construct and alcohol motivation and drinking behavior among Latinx adults who are hazardous drinkers with clinical anxiety. The current study utilized ecological momentary assessment (EMA) to characterize, in real time, the influence of momentary experiential avoidance (EA) in the relationship between ethnic discrimination and alcohol use motivation (craving, intention to drink, and coping motives) as well as alcohol use behavior (frequency of consumption and negative consequences). The sample consisted of 122 (56.6% female; Mage = 33.80 years, SD = 7.45 years) Latinx adults who met criteria for clinical anxiety and hazardous drinking. Participants completed a baseline survey followed by EMA across a 14-day period. The mediational role of momentary EA was first examined within the relationship of baseline reports of ethnic discrimination history, and the alcohol criterion variables. In contrast to expectation, these results did not emerge as statistically significant. Exploratory models were then conducted aimed at evaluating the mediational role of daily ethnic discrimination and EA for the alcohol motivation and use variables. Results indicated that momentary EA plays a mediational role between daily ethnic discrimination and alcohol use outcomes, most notably at the within-person level (alcohol motivation: B = 0.041, SE = 0.15, p = 0.006; hazardous drinking: B = 0.038, SE = 0.018, p = 0.031). At the between-person level, EA mediated the relationship between daily ethnic discrimination and alcohol motivation (B = 0.205, SE = 0.064, p = 0.001) and hazardous drinking (B = 0.196, SE = 0.093, p = 0.034). Given that EA is readily targeted in psychological treatments for anxiety and alcohol misuse, the results from the current work provide initial empirical evidence to assess and target momentary EA in the context of (daily) ethnic discrimination in the service of reducing alcohol use disparities among Latinx persons who are hazardous drinkers with comorbid clinical anxiety
Longitudinal High-Resolution Imaging of Retinal Sequelae of a Choroidal Nevus
No full text<b>Background</b>: Choroidal nevi are common, benign tumors. These tumors rarely cause adverse retinal sequalae, but when they do, they can lead to disruption of the outer retina and vision loss. In this paper, we used high-resolution retinal imaging modalities, optical coherence tomography (OCT) and adaptive optics scanning laser ophthalmoscopy (AOSLO), to longitudinally monitor retinal sequelae of a submacular choroidal nevus. <b>Methods</b>: A 31-year-old female with a high-risk choroidal nevus resulting in subretinal fluid (SRF) and a 30-year-old control subject were longitudinally imaged with AOSLO and OCT in this study over 18 and 22 months. Regions of interest (ROI) including the macular region (where SRF was present) and the site of laser photocoagulation were imaged repeatedly over time. The depth of SRF in a discrete ROI was quantified with OCT and AOSLO images were assessed for visualization of photoreceptors and retinal pigmented epithelium (RPE). Cell-like structures that infiltrated the site of laser photocoagulation were measured and their count was assessed over time. In the control subject, images were assessed for RPE visualization and the presence and stability of cell-like structures. <b>Results</b>: We demonstrate that AOSLO can be used to assess cellular-level changes at small ROIs in the retina over time. We show the response of the retina to SRF and laser photocoagulation. We demonstrate that the RPE can be visualized when SRF is present, which does not appear to depend on the height of retinal elevation. We also demonstrate that cell-like structures, presumably immune cells, are present within and adjacent to areas of SRF on both OCT and AOSLO, and that similar cell-like structures infiltrate areas of retinal laser photocoagulation. <b>Conclusions</b>: Our study demonstrates that dynamic, cellular-level retinal responses to SRF and laser photocoagulation can be monitored over time with AOSLO in living humans. Many retinal conditions exhibit similar retinal findings and laser photocoagulation is also indicated in numerous retinal conditions. AOSLO imaging may provide future opportunities to better understand the clinical implications of such responses in vivo
The Great Indian Divide of 1947: Told by Two Generations
No full textMy work as a Senior Honors Thesis student and FrameWorks fellow focuses on partition literature that emphasizes themes of displacement, loss, and trauma that originated from the 1947 Partition of British India into India and (East and West) Pakistan. I analyze the works of first-generation authors (partition survivors who wrote literature based on their first-hand experiences) and second-generation authors (individuals who wrote partition literature from historical context and inherited memories). I noticed the resurgence of partition literature for adolescents, thus leading me to my research question: To what extent do second-generation partition narratives from authors who inherited memories of first-generation writers preserve themes of identity from the great partition of 1947 in ways South Asian communities of today can understand? I looked at previous scholarships, compared first and second-gen literature, and investigated the healing period of the partition to help close the gap in my research question. Additionally, I discovered methods of second-gen authors and how they use their works to invoke critical thinking in modern South Asian communities about the complexities of partition.English, Department ofHonors Colleg
Health Harming Legal Needs and Their Relationship with Mentally Unhealthy Days in Participants Screened for a Medical Legal Partnership
No full textThere is a growing awareness of how legal concerns regarding financial instability, legal and civil matters, and/or basic necessities can negatively affect the physical and mental health quality of an individual, also known as health-harming legal needs (HHLNs). Medical Legal Partnerships (MLPs), a collaboration between healthcare providers and legal aid organizations, aim to meet these legal needs by incorporating referrals to legal services for those who need it into primary care clinics. While research exploring the adverse health outcomes of HHLNs expands, there is still a gap in how HHLNs addressed by MLPs affect mental health quality specifically. A cross-sectional study was carried out to address the complex relationship between legal needs and recent mental health quality among clinic patients screened for participation in an MLP program. Data was collected through voluntary patient participation in completing a MLP screening form distributed by the UH Family Care Center clinic, which assessed 16 different HHLNs. To assess mental health quality, the measure of Mentally Unhealthy Days, MUDs, from the Health-Related Quality of Life survey was used. A multivariate ZINB regression model was used to identify independent predictors of mental health quality. Both reporting at least one HHLN and each additional HHLN was associated with a lower likelihood of zero MUDs in unadjusted models. Worry about housing loss was the only HHLN associated with an increase in the number of MUDs, with or without adjusting for demographics and other HHLNs.Medicine, Tilman J. Fertitta Family College ofHonors Colleg
Machine Learning Applications in Gray, Blue, and Green Hydrogen Production: A Comprehensive Review
No full textHydrogen is increasingly recognized as a key contributor to a low-carbon energy future, and machine learning (ML) is emerging as a valuable tool to optimize hydrogen production processes. This review presents a comprehensive analysis of ML applications across various hydrogen production pathways, including gray, blue, and green hydrogen, with additional insights into pink, turquoise, white, and black/brown hydrogen. A total of 51 peer-reviewed studies published between 2012 and 2025 were systematically reviewed. Among these, green hydrogen&mdash;particularly via water electrolysis and biomass gasification&mdash;received the most attention, reflecting its central role in decarbonization strategies. ML algorithms such as artificial neural networks (ANNs), random forest (RF), and gradient boosting regression (GBR) have been widely applied to predict hydrogen yield, optimize operational conditions, reduce emissions, and improve process efficiency. Despite promising results, real-world deployment remains limited due to data sparsity, model integration challenges, and economic barriers. Nonetheless, this review identifies significant opportunities for ML to accelerate innovation across the hydrogen value chain. By highlighting trends, key methodologies, and current gaps, this study offers strategic guidance for future research and development in intelligent hydrogen systems aimed at achieving sustainable and cost-effective energy solutions
Exploring the Temporal Links Between Minority Stress, Allostatic Load, and Substance Use: A Systematic Review of the Literature
No full textThis systematic literature review examined the temporal link between chronic stress associated with marginalized identities (LGBTQ+ individuals) and its impact on physiological changes and substance use. As defined in Meyer 2003, Minority Stress Theory provides the framework for understanding how distal stressors (e.g., discrimination, institutional barriers) and proximal stressors (e.g., internalized stigma, fear of rejection) contribute to chronic stress and physiological dysregulation. Allostatic load is described as the cumulative physiological toll of extended periods of stress, which leads to increase in hormone dysregulation and risk of chronic disease. This review discusses the connection between minority stress and substance use as a coping mechanism, and its impacts on psychopathology. A systematic search following PRISMA guidelines was conducted using the University of Houston Libraries database, identifying 33 relevant studies, with five meeting the full inclusion criteria. Findings showed an association between minority stress, allostatic load, and substance use. However, gaps were found in regards to their temporal relationship. Challenges included limited longitudinal studies and inconsistency among mental health measures in assessing allostatic load and in methodology. Future research should explore targeted interventions to reduce physiological dysregulation and substance use disorders among LGBTQ+ individuals.Psychological, Health, and Learning Sciences, Department ofHonors Colleg
The Role of Culture as a Social Determinant of Healthcare Experiences of Arab Americans
No full textAcculturation is the process through which cultures come into prolonged contact with an ethnically distinct dominant culture, while individuals attempt to maintain a coherent sense of self. Arab American immigrants face distinct experiences in the United States that affect their cultural identities and integration into U.S. society. The current study explores culture as a social determinant of health awareness, and healthcare access and quality among Arab Americans in the U.S. A mixed-methods approach was conducted with 20 Arab American participants using in-depth structured interviews with the development of a culture-centered, health-related interview. Participants demonstrated their apprehension of health as a holistic concept, and perceptions of their exposure to healthcare services, including the factors that encouraged or restrained them from accessing these services. Additionally, the Middle East North Africa Identity Measure was used to survey participant ethnic identity and cultural affiliation. Thematic analysis revealed the complex ways in which culture, religion, and family influence Arab Americans as limiters and promotors to healthcare experiences. While cultural norms may encourage self-care and healthy lifestyles, they may also discourage seeking medical treatment, especially for mental health issues. Religion was found to be a flexible, rather than limiting factor in healthcare experiences. Furthermore, participants conveyed a preference for healthcare providers of a similar ethnic background due to perceived cultural understanding and comfort. These insights highlight the need for enhancing providers' cultural competency through the development of cultural-sensitivity education programs and cross-cultural training.Psychological, Health, and Learning Sciences, Department ofHonors CollegeBiology and Biochemistry, Department o