19304 research outputs found
Sort by
Controlled Incremental Filtration for Size-Based Cell Separation: Applications in Volume Reduction, Leukoreduction, and Large/Small Platelet Studies
No full textPlatelet transfusion is a critical therapy for patients at risk of bleeding, but conventional platelet products often present challenges due to large volumes and residual leukocytes, leading to adverse reactions and alloimmunization. This dissertation explores innovative microfluidic technologies for improving platelet transfusion safety and efficacy through volume reduction and leukoreduction. The research begins with a comprehensive review of emerging microfluidic passive separation techniques for enriching platelets and depleting leukocytes. It outlines performance requirements, standard metrics, and challenges that must be addressed for these technologies to enable low-risk, high-quality platelet transfusions. The review highlights the potential of microfluidic devices to overcome limitations of traditional centrifugation and filtration methods, which are costly, complex, and can degrade platelet quality. Building on this foundation, the dissertation presents the development and validation of a novel microfluidic device based on controlled incremental filtration (CIF) for separating platelets by size without the cell damage associated with centrifugation. This device addresses the challenge of investigating the relationship between platelet size and function, which has significant implications for transfusion medicine. The CIF device's performance was evaluated using platelet samples derived from whole blood and compared with traditional centrifugation methods. Results demonstrate that the CIF device produces 'large platelet' fractions equivalent to those from centrifugation, while generating superior 'small platelet' fractions with less contamination from large platelets. Importantly, the CIF device offers continuous, flow-through, single-step processing without causing platelet aggregation or requiring additional anticoagulants. This research contributes to the advancement of platelet separation techniques, potentially accelerating studies on the relationship between platelet size and function. Moreover, it paves the way for improved transfusion practices, particularly in pediatric settings where low-volume, high-quality platelet transfusions are crucial. The findings of this dissertation have significant implications for enhancing the safety, efficacy, and accessibility of platelet transfusions across various clinical scenarios
Minimal Colloidal Model Nucleates and Crystallizes from Dilute Solution Obeying Classical Theory
No full textA fundamental assumption of the classical theories of crystal nucleation is that the individual molecules from a supersaturated medium associate to an emerging nucleus individually and sequentially. Numerous recent studies of crystal nucleation in solution have revealed nonclassical pathways, whereby crystal nuclei are hosted and fed by amorphous clusters pre-formed in the solution. A sizable knowledge gap has persisted, however, in the definition of the molecular-level parameters that direct the nucleation pathways. The relevance of classical theory as a quantitative predictor of nucleation behavior—and not just a general guide—has been questioned. Here we construct a suspension of colloid particles and monitor their individual motions towards a quasi-two-dimensional crystal by scanning confocal microscopy. We combine electrostatic repulsion and polymer-induced attraction to obtain a simple isotropic pair interaction potential with a single attractive minimum of tunable depth. We show that even the smallest aggregates that form in this system structure as hexagonal two-dimensional crystals and grow and mature by the association and ex- change of single particles from the solution, signature behaviors during classical nucleation. Empowered by the particle large size and slow diffusion, we directly observe the particle-crystal dynamics during nucleation. We show that the equilibrium behaviors of crystals, the Gibbs barrier to nucleate new crystals, and the nucleation rate comply, uniquely, with the predictions of thermodynamic and kinetic parts of classical nucleation theory (CNT). The particles in the suspension equilibrate with those in the clusters and the volume fractions of suspensions at equilibrium, the particle solubility, correspond to straightforward thermodynamic predictions based on depth of the interparticle attraction. Direct observations of the evolutions of small crystals reveal the size of the critical nucleus, about three parti- cles. This measurement complies remarkably well with a straightforward evaluation based on classical theory and the depth of the pair potential between two particles. The rate of nucleation of hexagonal crystals increases quasi-exponentially with supersaturation at low and moderate supersaturations. This correlation supports a determination of the Gibbs free energy barrier for nucleation, which is similar to a value computed based on the nucleus size. We measure the frequency of attachment of particles to large crystals and use it as input to reproduce the pre-exponential factor in the rate expression of CNT. At elevated supersaturations, the nucleation rate decouples from supersaturation. The nucleation theorem attributes this singularity to transition to nuclei consisting of one molecule and nucleation confronted by a negligible barrier. This shift to a spinodal-like regime presents the only deviation from CNT predictions. Direct monitoring of crystal nucleation by a non-invasive technique demonstrates nearly-strict adherence to CNT, whereby the particle interaction potential fully predicts the during crystal nucleation. Particle interaction plays a crucial role in colloidal phase behavior. By alternating the potential well depth, we demonstrated the possible changes in cluster growth mechanism and structures
Antibody-Conjugated Gold Nanorods As Photoacoustic Imaging Contrast Agents to Target the Heart
No full textCurrent imaging modalities (such as MRI, CT, and fluoroscopy) used by clinicians to visualize the myocardium do not highlight specific regions, like the cardiac conduction system (CCS). Photoacoustic imaging (PAI) offers a diagnostic platform that uses light energy to induce thermoelastic expansion of tissues whereby the resulting ultrasonic transmissions are detected. We hypothesize that nanoengineered gold can serve as a strong PAI contrast agent that can be modified to target CCS cells. Here, we show that gold-nanorods absorb light in the near-infrared, provide high PAI signal, and permit antibody conjugation for cellular targeting. Gold-nanorods (15 x 55 nm in size), analyzed using UV-Visible spectroscopy, dynamic light scattering, and zeta potential, absorbed light at ~800 nm and remained stable in solution with a surface charge around -20 to -30 mV. Phantom models using 3D printed silicon molds containing gold-nanorod gelatin mixtures permitted PAI visualization. The molds hold a gelatin base and 1% milk backfill to mimic tissue scattering effects. The strong PAI signal observed in this phantom as the gold-nanorod concentration increased was linear at laser excitation wavelengths of 780 and 800 nm, R2 = 0.986 and 0.989, respectively. Preliminary studies suggest antibody-conjugated gold-nanorods are a promising agent for targeted PAI. The results of this study have significant clinical implications for advancing cardiac imaging and would be 'game changing' to aid clinicians in identifying the specialized network of cells known as the cardiac conduction system for intraoperative lead placement. [This project was completed with the contributions from Blake C. Fallon, Antonio Martino, and Carly S. Filgueira from the Houston Methodist Research Institute, Samuel John and Richard R. Bouchard from UT MD Anderson Cancer Center, and Nilesh Mathuria from the Houston Methodist Hospital.]Chemical and Biomolecular Engineering, William A. Brookshire Department ofHonors Colleg
Synthetic Microbial Communities for Plant Stress Tolerance
No full textClimate change-induced environmental pressures exacerbate abiotic stress in crops, reducing yield and threatening global food security. This study explores the potential of Synthetic Microbial Communities (SynComs) to enhance soybean resilience under salinity stress. Soybean plants were inoculated with Bacillus consortia comprising of 5, 10, and 20 strains before exposure to NaCl stress at the V2 growth stage. Post-harvest analyses included biomass measurements, enzyme activity assays, gene expression profiling, root colonization assessment, and metabolite profiling. Results indicated that saline stress alone promoted root elongation, while saline-treated plants with consortia exhibited reduced biomass, suggesting a trade-off between growth and defense under microbial-assisted stress tolerance. Metabolite analysis revealed that oxalic and succinic acids increased under salinity, quinic acid was suppressed, and citric acid, which peaked in non-saline conditions, declined with salt stress. These shifts highlight key metabolic responses to salinity. While microbial consortia influence plant adaptation to salinity, their variable effects on growth and metabolism emphasize the need for optimizing SynCom interactions to enhance stress resilience in crops.Engineering Technology, Department ofHonors Colleg
Interstate Water Compacts: Gauging Effectiveness and Adaptability to Climate Change
No full textInterstate water compacts (IWCs) are agreements between multiple states that must be approved by Congress. They are created to manage and allocate shared water resources. A key problem, however, is that water resources are susceptible to ever-increasing impacts from climate change. If IWCs do not have an effective governance mechanism nor adequate measures for monitoring water resources, then IWCs are insufficient and inefficient, and therefore vulnerable to climate change. This research analyzes 25 IWCs to identify how they vary among eight factors that are common to each IWC. The result of an extensive analysis of the eight factors for each of the IWCs was a model IWC that prescribes the ideal extent to which it must prepare for climate change. This research found issues within each IWC. While many IWCs carry a great concern for water apportionment between states, this is often done with little regard for long term impacts. The research also found very little concern for water conservation and ecosystem protection in compacts signed prior to 1965, all of which are still active.Honors CollegePolitical Science, Department o
Long-Term Subsidence Assessment by LiCSBAS and Emerging Hot Spot Analysis in Kathmandu Valley
No full textRapid urbanization in Kathmandu Valley has strained its aquifer system, causing significant land subsidence. This study employs LiCSBAS for InSAR processing of Sentinel-1 data (2017–2024) to map subsidence-prone areas. The significant subsidence was found in northwest (Baluwatar, Samakhusi, and Manmaiju), southern (Gwarko, Patan, and Koteshwor), and northeast (Madhapur Thimi and Gathhaghar) regions with a maximum subsidence rate ~21 cm/yr. Subsidence has also expanded towards the outskirts and open areas in the eastern and southern parts of Lalitpur and Bhaktapur districts. Emerging hot spot analysis reveals a slowing subsidence trend in high-risk zones, possibly linked to the MWSP project reducing groundwater extraction from 58 MLD (2021) to 26 MLD (2024). Many subsidence-affected areas are located over the Kalimati and Gokarna Formations in highly urbanized areas. The key contributing factors to subsidence are soil compaction, excessive groundwater use, and urban sprawl encroaching open areas and recharge zones. These findings underscore the urgent need for sustainable groundwater management and land-use planning to promote urban resilience
Spatial Super-Resolved Fluorescence Lifetime Imaging Microscopy (FLIM) Using a Compress Sensing Strategy
No full textOur goal is to enhance Fluorescence Lifetime Imaging Microscopy (FLIM) by integrating super-resolution techniques (PALM) and compressed sensing strategies into a unified imaging system. This approach will allow for faster imaging speeds compared to traditional scanning methods, along with high spatial and temporal resolution for each image. This approach reduces photobleaching and phototoxicity while achieving faster imaging speeds without sacrificing spatial or temporal resolution. By enabling efficient imaging of complex cellular dynamics, compressed sensing FLIM using PMTs could enhance our understanding of biological processes and improve disease diagnosis. Diseases, especially cancers, neurodegenerative conditions, and infectious diseases, often manifest first as abnormalities within cells or even within subcellular structures. Detecting these early molecular changes with high-resolution imaging is crucial for understanding disease progression and developing targeted treatmentsChemistry, Department ofHonors CollegeBiology and Biochemistry, Department o
Arab Migration in Gulf Coast Foodways
No full textThis project looks at how Arab migration to southeast Texas helped shape regional food-ways. This is part of a larger project by Dr. Todd Romero that looks at the impact violence, migration, and colonialism have shaped foodways in South Louisiana and Southeast Texas.History, Department ofHonors CollegeMarketing and Entrepreneurship, Department o
Caregiving with Gratitude: Gendered Roles and Experiences of Latina Caregivers Providing Familial and Hospice Care in Texas
No full textLatino culture emphasizes family values such as respect and care for their elders. Traditionally, Latinas are obligated to fulfill these duties/expectations which require them to prioritize family. Many first-born or oldest Latinas are sometimes expected to take on the role of caregiver with younger siblings and/or aging parents (Longoria et al 2020). This is due to external factors such as culture, gender dynamics or the lack of a parent figure. This study focuses on sixteen Latina caregivers in Texas where the second highest Latino population resides, according to the U.S. Bureau of the Census 2021 (Moslimani and Bustamante 2023). Based on socio cultural values found in this community, Latina caregivers may experience long-term health issues physically, psychological, and emotional outcomes of caring and may neglect their own health due to their high cultural commitment to caregiving. I use a qualitative approach to examine the role, challenges and experiences Latinas faced while providing care. I also examined their coping mechanisms and if acculturation is present in the ways they provide care services. The participants in the study showed how Latino culture is deeply rooted which is not necessarily a negative thing. Many Latina caregivers showed positive feelings and gratitude for being able to provide care for family/patients and are not worried of long-term effects they may suffer in the future. While participants reflect the findings of unmarried or childless Latinas as the primary caretakers, the most significant findings in this study are the way Latinas cope and how spirituality aids them overcome the bad days of caregiving
AMYLIN: A Potential Contributor of Amyloid Beta Aggregation
No full textAmyloid beta and amylin are two proteins that have gained a lot of attention in recent years because of their potential involvement in the development of Alzheimer's disease and Type II diabetes, respectively. The proteins are noted to have several similarities including their size, since amyloid beta is approximately 40 amino acids long and amylin is known to be 37 amino acids long, and their ability to oligomerize. In fact, it is their ability to form oligomers that has been indicated as why they are able to contribute to the development of Alzheimer's disease and Type II diabetes. However, there is newer evidence coming out in support of amylin as a contributor to the development of Alzheimer's disease. The mechanism of action that results in amylin having a role in the development of Alzheimer's disease is unclear. Our work centers around understanding how amylin may be a contributor to the development of Alzheimer's disease because of its oligomerization properties. In this study, we analyzed the impact of amylin on the ability of amyloid beta to aggregate. Immunological techniques were used in order to investigate the relationship between the two proteins. For recognition and binding of an antigen to antibody, the Dot Blot assay was used. Both amyloid beta and amyloid beta plus amylin were simultaneously made through serial dilutions to see a trend in oligomerization. Our work illustrates novel results because we see that in the presence of amylin there is an increase in oligomerization of amyloid beta. This information is significant because oligomerization of amyloid beta has been shown to be linked to amyloid beta plaque formation in the brain and the possible development of Alzheimer's disease. The ability of amylin to cause both pancreatic beta cell dysfunction and amyloid beta plaque formation through oligomerization is novel and may lead to a deeper understanding of how oligomerization starts and stops. This new information could lead to the development of novel therapeutics in the fight against Alzheimer's disease and potentially Type II diabetes.Honors CollegeMedicine, Tilman J. Fertitta Family College o