Quantifying the Hydrological Setting of Upper Flow Regime Channels of the Triassic Dockum Group of West Texas

Type: Graduate
Author(s): Samuel Walker Geological Sciences John Holbrook Geological Sciences
Advisor(s): John Holbrook Geological Sciences

The Triassic Dockum Group of the western Texas High Plains is studied in depth paleontologically, but until recently lacked a detailed sedimentological evaluation. Recent research of the Dockum Group in Palo Duro Canyon, Texas, provides new interpretations of the complex fluvial lacustrine strata of the comprising formations based on analysis of individual lithofacies. Identified within the lithofacies assemblages are numerous channel belts composed of upper flow regime bedforms. Observed upper flow regime bedforms in outcrop range from upper plane bed, antidunes, breaking antidunes, chutes and pools, and cyclic steps with increasing flow velocity respectively. These channel belts record extreme flow events from repeating massive storms that perpetuated throughout the Texas region of Triassic Pangea. These unique reservoir-quality channels are interpreted to be resultant of a megamonsoonal climate producing massive pulses of rapid flow allowing for the preservation of upper flow regime bedforms. While these channels are identified in outcrop they have not been quantified in distribution, variability in fill, connectivity and formative discharge.
This study aims to test the megamonsoonal hypothesis by quantifying the discharge of these channels and testing if the distribution density and paleodischarge of these channels is consistent with local dominance of megamonsoonal conditions. Upper flow regime structures are rarely preserved in the rock record and extremely difficult to observe directly during natural formation in modern rivers. Most of the equations used to quantify flow conditions for these structures are derived from flume tank experiments. These are applied to the upper flow regime bedforms found in outcrops of the Dockum Group to reconstruct paleohydrology. Current flume tank research reinforces Kennedy’s equations defining relationships between the wavelengths of stable antidune apexes (λ), mean flow depth (hm) and mean flow velocity (U). These equations are modified to account for different upper flow regime structures formed under increasing velocity and discharge identified in outcrop. Bedform distribution, size, and type are variables determined from outcrop measurement. Paleoflow velocities, Froude numbers and relative water depths are determined with an observed margin of error. Scaling relationships and field measurements provide constraints on channel cross sectional area and channel-belt density. This data along with grain size distribution provides tangible numbers for calculating formative discharge. Preliminary results align with data from flume tank experiments and are consistent with major floods produced by substantial storm events verifying the megamonsoonal hypothesis.

Campanian-Maastrichtian Ankylosaurs of West Texas

Type: Graduate
Author(s): Bryanna West Geological Sciences
Advisor(s): Arthur Busbey Geological Sciences

Deeper Exploration of the C*-Algebras Arising from Uniformly Recurrent Subgroups and their Relationship with Crossed Products

Type: Graduate
Author(s): Douglas Wagner Mathematics
Advisor(s): José Carrión Mathematics

A group is a mathematical construct that represents the symmetries of an object. These symmetries transform the object through what is called a group action. Graphs—Cayley graphs, in particular—provide a rich source of symmetries for forming groups. A graph and its group action can be modeled by a collection of infinite matrices known as a C*-algebra. In a paper in the Journal of Functional Analysis, Gábor Elek used dynamical systems called Uniformly Recurrent Subgroups (URS) to construct a new type of C*-algebra. We further develop understanding of these C*-algebras using tools from other areas of operator theory. In particular, comparisons with the well-known crossed-product construction have proven useful.

Graphene Quantum Dot Formulation for Cancer Imaging and Redox-Based Drug Delivery

Type: Graduate
Author(s): ELIZABETH CAMPBELL Physics & Astronomy Giridhar Akkaraju Biology Roberto Gonzalez-Rodriguez Chemistry & Biochemistry Kayla Green Chemistry & Biochemistry Tanvir Hasan Physics & Astronomy Bong Lee Physics & Astronomy Anton Naumov Physics & Astronomy Tate Truly Biology
Advisor(s): Anton Naumov Physics & Astronomy

Treatment of complex conditions, such as cancer, has been substantially advanced by a field of molecular therapeutics. However, many of these therapies are limited by the dose toxicity and lack the predictive power of tomography-guided approaches. Nanomaterial platforms can address these drawbacks, safely delivering therapeutics, concomitantly imaging their delivery pathways, and presenting sites for targeting agent attachment. Graphene quantum dots (GQDs) possess physical properties that are critical for biomedical applications, including small size (3-5 nm), high quantum yield, low cytotoxicity, and pH-dependent fluorescence emission. Nitrogen doped graphene quantum dots (N-GQDs) are now utilized as a platform for a targeted treatment formulation geared toward cancer therapeutic. Our work utilizes nitrogen-doped GQDs as an emissive platform for covalent attachment of a targeting agent (hyaluronic acid (HA) targeted to the CD44 receptors on several cancer cell types) and oxidative stress-based cancer therapeutic (ferrocene (Fc)). The synthesized multifunctional formulation is characterized and its efficacy evaluated in vitro. Elemental mapping indicates that the purified from reactants synthetic product has an average iron content of 0.64 atomic percent, suggesting the successful attachment of the therapeutic, while FFT analysis of TEM images confirms the crystalline structure of the GQDs. Although GQDs alone yield no cytotoxicity as quantified via the MTT assay up to the maximum imaging concentrations of 1 mg/mL, the Fc-HA-GQD formulation exhibits a higher cytotoxic response in the cancer cells (HeLa) targeted by the HA as opposed to healthy ones (HEK-293) that do not overexpress CD44, suggesting cancer-selective targeted efficacy. As Fc induces oxidative stress that is less mitigated in cancer cells, we expect it to also contribute to the observed cancer-selective treatment response. As a result, we propose Fc-HA-GQD formulation as a multifunctional targeted delivery, imaging, and cancer-specific treatment agent further to be studied in vivo.

Surface Plasmon Coupled Emission: a new super sensitive technique

Type: Graduate
Author(s): Luca Ceresa Physics & Astronomy
Advisor(s): Zygmunt Gryczynski Physics & Astronomy

Fluorescence has proved itself to be a useful tool in a wide variety of fields, ranging from environmental sensing to biomedical diagnostics. In this study, we propose to utilize a novel fluorescence-based technique called Surface Plasmon Coupled Emission (SPCE) to monitor molecular binding and to detect low concentrations of physiological markers (e.g. biomarkers present in the human body as a result of a disease). SPCE is characterized by directional emission that allows for a superior sensitivity and selectivity for detection. The development of an SPCE-based detection platform will allow for simple, fast and sensitive detection in a compact configuration that can be relatively easily implemented in the field or in primary care offices. Surface plasmon induced fluorescence at the interface of a thin metal layer (e.g. 50 nm of silver or gold) and a dielectric (e.g. glass) allows for highly enhanced excitation of fluorophores deposited on top of the metal film and very efficient detection due to the directional nature of this emission. As a result, we expect highly improved detection sensitivity compared to other fluorescence detection methods or other surface detection methods such as surface plasmon attenuated reflection (SPR).