Digital Commons Network^™

Selective Hydrolysis Of Heterooligosaccharides By Poly(Acrylate) Gel Catalysts, Susanna Striegler

Chemistry & Biochemistry Faculty Publications and Presentations

Natural glycoside hydrolases are distinguished by their ability to hydrolyze glycosidic bonds with high efficiency and selectivity. This feature is achieved through specific interactions in the active site during catalytic turnover and is not just facilitated by two catalytically active amino acids. Intrigued by these features, a biomimetic α-galactosidase mimic was developed using an empirical catalyst design. Starting with a library of 704 gels of which 250 have a unique composition synthesized from TEGDMA cross-linker and 7 selected monomers, 238 monomodal gels are evaluated for their ability to hydrolyze the 1→6 α-glycosidic bond in the disaccharide melibiose. Among those, 13 …

Predicting Spatiotemporal Patterns Of Productivity And Grazing From Multispectral Data Using Neural Network Analysis Based On System Complexity, Amanda J. Ashworth, A. Avila, H. Smith, T. E. Winzeler, P. Owens, C. Flynn, P. O'Brien, D. Philipp, J. Su

Environmental Dynamics Faculty Publications and Presentations

Remote sensing tools, along with Global Navigation Satellite System cattle collars and digital soil maps, may help elucidate spatiotemporal relationships among soils, terrain, forages, and animals. However, standard computational procedures preclude systems-level evaluations across this continuum due to data inoperability and processing limitations. Deep learning, a subset of neural network, may elucidate efficiency of livestock production and linkages within the livestock-grazing environment. Consequently, we applied deep learning to environmental remote sensing data to (1) develop predictive models for yield and forage nutrition based on vegetation indices and (2) at a pixel-level (per 55 m²), identify how grazing is …

Estimating Prevented Planting Coverage Factor Variation, Christopher N. Boyer, Eunchun Park, Chad Hellwinckel, S. Aaron Smith, William Maples, Gabriela Perez-Quesada

Agricultural Economics and Agribusiness Faculty Publications and Presentations

Prevented planting payments reimburse crop producers for losses from not being able to plant. These payments provide critical protection to producers; however, these payments, which are determined using a nationwide, crop-specific coverage factor, have been questioned to induce moral hazard. Depending on the region and crop insurance coverage, payments from this provision exceed producers’ losses. This paper estimates the prevented planting coverage factor by coverage level and region that would equitably reimburse corn and soybean producers for their losses. We find the prevented planting coverage factor has significant variation across coverage levels and location within our study region. The prevented …

Vegetation Masking Of Remote Sensing Data Aids Machine Learning For Soil Fertility Prediction, Hans Edwin Winzeler, Marcelo Mancini, Joshua Michael Blackstock, Zamir Libohova, Phillip R. Owens, Amanda J. Ashworth, David Miller, Sergio Silva

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Soil nutrient content varies spatially across agricultural fields in hard-to-predict ways, particularly in floodplains with complex fluvial depositional history. Satellite reflectance data from the Sentinel-2 (S2) mission provides spatially continuous land reflectance data that can aid model development when used with point observations of nutrients. Reflectance from vegetation is assumed to obstruct land reflectance of bare soil, such that researchers have masked vegetation in models. We developed a routine for masking vegetation within Google Earth Engine (GEE) using Random Forest classification for iterative application to libraries of S2-images. Using gradient boosting, we then developed soil nutrient models for surface soils …

Laser Doppler Velocimetry And Particle Image Velocimetry Measurements In A Wind Tunnel Model Of The Jack Rabbit Ii Special Sonic Anemometer Study, Paulo V.D.F. Lopes, Thomas Spicer, Chad T. Smith

Chemical Engineering Faculty Publications and Presentations

A 1:50 scale model of the Jack Rabbit II (JR-II) Mock Urban Environment (MUE) was constructed in the wind tunnel of the University of Arkansas. Laser Doppler Velocimetry (LDV) measurements show agreement between the approach wind characteristics in the tunnel model and field test. LDV velocity measurements within the MUE wind tunnel model also agree with the anemometry results obtained in JRII Special Sonic Anemometer Study (JRII-S) conducted in 2016.

After demonstrating that the wind tunnel models the JRII-S field test with LDV measurements, Particle Image Velocimetry (PIV) experiments were conducted to provide velocity measurements that could not be obtained …

Self-Replication Via Tile Self-Assembly, Andrew Alseth, Daniel Hader, Matthew J. Patitz

Computer Science and Computer Engineering Faculty Publications and Presentations

In this paper we present a model containing modifications to the Signal-passing Tile Assembly Model (STAM), a tile-based self-assembly model whose tiles are capable of activating and deactivating glues based on the binding of other glues. These modifications consist of an extension to 3D, the ability of tiles to form “flexible” bonds that allow bound tiles to rotate relative to each other, and allowing tiles of multiple shapes within the same system. We call this new model the STAM*, and we present a series of constructions within it that are capable of self-replicating behavior. Namely, the input seed assemblies to …

Early Season Wheat Response To Electrochemically Precipitated Struvite In Various Soils In The Greenhouse, Tatum Simms, Kristofor R. Brye, Trenton L. Roberts, Lauren F. Greenlee

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Fertilizer-phosphorus (P) materials can be recovered from wastewater and used to supplement mined phosphate rock, where one such material is struvite [MgNH4PO4·6(H2O)]. This study aimed to compare electrochemically precipitated struvite (ECST) reclaimed from synthetic wastewater to other commercial fertilizer-P sources in cultivated soils from Arkansas [silty clay loam (AR-SiCL) and silt loam (AR-SiL)], Missouri [(silt loam; MO-SiL 1 and 2)], and Nebraska [silt loam (NE-SiL) and sandy loam (NE-SL)]. A greenhouse pot study was conducted for 60 days with unvernalized wheat (Triticum aestivum) using five fertilizer-P sources [ECST, chemically precipitated struvite (CPST), monoammonium phosphate (MAP), triple superphosphate (TSP), …

Reactive Dye Wash-Off Processing Of Cotton Fabrics Using Polymer Dye Transfer Inhibitors For Sustainable Dyeing, Muhammad Nazrul Islam, Tuba Toprak-Cavdur, Safiqul Islam, Fatema Tarannum, Keisha Walters

Chemical Engineering Faculty Publications and Presentations

Cotton fiber consumption is higher than any other natural fiber due to its superior mechanical and physical properties. In the conventional reactive dyeing process, the dye undergoes hydrolysis due to hydrogen bonding and weak Van der Waals forces, yielding poor washing color fastness. Additionally, the post-dyeing wash-off process consumes significant amounts of water, energy, and time in order to remove the unreacted and hydrolyzed dye. Therefore, reactive dyes are predominantly utilized to color cotton fabrics as the covalent bond formed between dye and fiber results in excellent washing fastness for a wide range of colors, and improved ease of use. …

Noise Leads To The Perceived Increase In Evolutionary Rates Over Short Time Scales, Brian C. O'Meara, Jeremy M. Beaulieu

Biological Sciences Faculty Publications and Presentations

Across a variety of biological datasets, from genomes to conservation to the fossil record, evolutionary rates appear to increase toward the present or over short time scales. This has long been seen as an indication of processes operating differently at different time scales, even potentially as an indicator of a need for new theory connecting macroevolution and microevolution. Here we introduce a set of models that assess the relationship between rate and time and demonstrate that these patterns are statistical artifacts of time-independent errors present across ecological and evolutionary datasets, which produce hyperbolic patterns of rates through time. We show …

The Long Arm Of School Punishment: The Role Of School Suspension On Self-Rated Health From Adolescence To Midlife, Michael Niño, Alexa Angton, Kathryn Norton-Smith, Kayla Allison

Sociology and Criminology Faculty Publications and Presentations

School suspension has been linked to numerous adverse social outcomes in adolescence and adulthood. While research continues to highlight the deleterious consequences tied to suspension, less is known about how exposure to suspension influences health over the life course. Drawing from panel data, we address this gap by investigating whether school suspension is associated with self-rated health from adolescence to midlife. Compared to youth with no history of suspension, suspended youth were more likely to report poorer health in adolescence. Findings also demonstrate that school suspension plays a significant role in self-rated health patterns over time. Specifically, we find suspended …

Two-Dimensional Quantum Material Identification Via Self-Attention And Soft-Labeling In Deep Learning, Xuan Bac Nguyen, Apoorva Bisht, Benjamin Thompson, Hugh O.H. Churchill, Khoa Luu, Samee U. Khan

Electrical Engineering and Computer Science Faculty Publications and Presentations

Detecting two-dimensional (2D) materials in silicon chips presents a significant challenge in the field of quantum machines due to the difficulty of data collection. Specifically, among thousands of flakes, not all flakes are useful or well-annotated, resulting in noisy and hard samples within the dataset, which challenges the deep neural network (DNN) to learn. To address this problem, we propose a novel method for identifying quantum 2D flakes even when there is a high rate of missing annotations in the input images. In particular, we first propose a new mechanism for automatically detecting false negative flakes that are missing annotations. …

Glass Ceilings, Step Stools, And Sticky Floors: The Racialized Gendered Promotion Process, Christianne Corbett, Katherine E. Wullert, Shannon K. Gilmartin, Caroline Simard

Sociology and Criminology Faculty Publications and Presentations

Organizations play a central role in replicating societal inequalities. Despite theories of gendered and racialized organizations, evidence of unequal outcomes, and research on proposed mechanisms, we have few intersectional analyses demonstrating how the promotion process varies by race and gender across job levels in actual organizations. In this first-ever analysis of advancement in a U.S. firm by gender, race, and job, we run random effects logistic regression models on five years of novel longitudinal data from the software engineering workforce of a U.S.-based technology company. Results show intersectional performance-reward bias in patterns that help maintain the racialized gendered hierarchy so …

Tulane Virus Persistence And Microbial Stability In 3d Food Ink Under Various Storage Conditions: A Pre- And Post-Printing Analysis, Allyson N. Hamilton, Kristen E. Gibson

Food Science Faculty Publications and Presentations

3D food printers facilitate novel customization of the physicochemical properties of food. This study aimed to investigate the impact of storage conditions on the inactivation of the human norovirus surrogate, Tulane virus (TuV), within 3D printed foods. TuV-inoculated protein cookie food ink (∽ 4 log PFU/g) was distributed into 18 3D food printer capsules (50 g each); half immediately underwent extrusion. Storage of the capsules and printed food products at 20 °C (0, 6, 12, and 24 h), 4 °C (0, 1, 3, and 5d), and − 18 °C (0, 1, 3, and 5d) was completed before analysis for TuV …

Michael Mcgraw: Profile Of The Newest Chbc Faculty Member, Danna Jaimes-Fajardo, Jeremy J. Smith, Lutishoor Salisbury

University Libraries Faculty Publications and Presentations

Presents the research profile of Michael McGraw, Assistant Professor, Chemistry and Biochemistry department. It highlights his research interests, education, and impact of his research.

Deciphering The Interdomain Coupling In A Gram-Negative Bacterial Membrane Insertase, Adithya Polasa, Shadi A. Badiee, Mahmoud Moradi

Chemistry & Biochemistry Faculty Publications and Presentations

YidC is a membrane protein that plays an important role in inserting newly generated proteins into lipid membranes. The Sec-dependent complex is responsible for inserting proteins into the lipid bilayer in bacteria. YidC facilitates the insertion and folding of membrane proteins, both in conjunction with the Sec complex and independently. Additionally, YidC acts as a chaperone during the folding of proteins. Multiple investigations have conclusively shown that Gram-positive bacterial YidC has Sec-independent insertion mechanisms. Through the use of microsecond-level all-atom molecular dynamics (MD) simulations, we have carried out an in-depth investigation of the YidC protein originating from Gram-negative bacteria. This …

Synthesis Of Amorphous And Various Phase-Pure Nanoparticles Of Nickel Phosphide With Uniform Sizes Via A Trioctylphosphine-Mediated Pathway, David Thompson, Adam S. Hoffman, Zachary R. Mansley, Sarah York, Feng Wang, Yimei Zhu, Simon R. Bare, Jingyi Chen

Chemistry & Biochemistry Faculty Publications and Presentations

Nickel phosphides are of particular interest because they are highly active and stable catalysts for petroleum/biorefinery and hydrogen production. Despite their significant catalytic potential, synthesizing various phase-pure nickel phosphide nanoparticles of uniform size remains a challenge. In this work, we develop a robust trioctylphosphine (TOP)-mediated route to make highly uniform phase-pure Ni₁₂P₅, Ni₂P, and Ni₅P₄ nanoparticles. The synthetic route forms amorphous Ni₇₀P₃₀ nanoparticle intermediates. The reactions can be stopped at the amorphous stage when amorphous particles are desired. The amount of P incorporation can be controlled by varying …

Drying Techniques For Precooked Hybrid Rice To Ensure Quality Of Instantized Rice, Anne Adhiambo Okeyo, Kaushik Luthra, Justin Siebenmorgen, Alan R. Vazquez, Griffiths Atungulu

Food Science Faculty Publications and Presentations

Background and Objectives

Due to the emergence of new hybrid rice cultivars, rice processors must refine their processing protocols to maintain the production of high-quality products. This is crucial for the instant rice processing industry. Therefore, this study aims to refine current convective heated air-drying processing methods to suit the new hybrid rice cultivars intended for instant rice production. New strategies to dry cooked rice were investigated. These included drying in a stepwise manner with high (230–200°C) and medium (190–160°C) air temperatures and drying at constant high (200°C) and medium (160°C) air temperatures. Changes in quality attributes of two new …

Cyclic And Acyclic Acetals As Safe, Nonaqueous Formaldehyde Equivalents For The Synthesis Of Pillararenes, Babitha Machireddy, Maggie He

Chemistry & Biochemistry Faculty Publications and Presentations

Pillar[5]arene was synthesized using acyclic acetals diethoxymethane and dimethoxymethane, and cyclic acetals 1,3-dioxolane and 1,3,5-trioxane as an alternative to paraformaldehyde. Both Lewis and Brønsted acids were effective in catalyzing the hydrolysis of acetal and initiating the Friedel–Crafts reaction in pillararene synthesis.

Student Outcomes In Arkansas’S Open Enrollment Charter Schools: 2021 To 2023, Sarah Mckenzie

Arkansas Education Reports

This study examines student outcomes of value-added growth and weighted achievement of Arkansas’s open-enrollment public charter schools and traditional public schools. Using publicly available school-level data, we use weighted averages to account for variations in school size in analyzing student performance in English Language Arts (ELA) and mathematics from the 2020-21 school year to the 2023-23 school year. To aid interpretation of the results, we translate the scores of the open-enrollment charter group and the traditional public school group into statewide percentile ranks within year and outcome.

The results reveal that statewide, students attending open-enrollment charter schools are consistently demonstrating …

Alternate Conformational Trajectories In Ribosome Translocation, Jose L. Alejo, Dylan Girodat, Michael J. Hammerling, Jessica A. Willi, Michael C. Jewett, Aaron E. Engelhardt, Katarzyna P. Adamala

Chemistry & Biochemistry Faculty Publications and Presentations

Abstract

Translocation in protein synthesis entails the efficient and accurate movement of the mRNA-[tRNA]₂ substrate through the ribosome after peptide bond formation. An essential conformational change during this process is the swiveling of the small subunit head domain about two rRNA ‘hinge’ elements. Using iterative selection and molecular dynamics simulations, we derive alternate hinge elements capable of translocation in vitro and in vivo and describe their effects on the conformational trajectory of the EF-G-bound, translocating ribosome. In these alternate conformational pathways, we observe a diversity of swivel kinetics, hinge motions, three-dimensional head domain trajectories and tRNA dynamics. By finding …

The Effects Of Online Chemistry-Themed Design-Based Stem Education On Preservice Science Teachers’ Stem Awareness, Emine Sahin Topalcengiz, Burcin Acar-Sesen

Curriculum and Instruction Faculty Publications and Presentations

The study investigated the impact of Chemistry-Focused Online Science, Technology, Engineering, and Mathematics (STEM) teacher education on the awareness of STEM among preservice science teachers. A one-group pretest–posttest quasi-experimental weak design was used to determine changes in preservice teachers’ STEM awareness. During the study, a 14-week Chemistry-Focused Online STEM course was provided to preservice science teachers. As part of this course, the theoretical knowledge about STEM was explained to students, and afterward, they completed two modules. Furthermore, preservice teachers also developed their chemistry-themed STEM lesson plans at the beginning of the course, after explaining theoretical knowledge about STEM at the …

Identifying Student Profiles In A Digital Mental Rotation Task: Insights From The 2017 Naep Math Assessment, Xin Wei, Susu Zhang, Jihong Zhang

Counseling, Leadership, and Research Methods Faculty Publications and Presentations

Mental rotation (MR), a key aspect of spatial reasoning, is highly predictive of success in STEM fields. This study analyzed strategies employed by 27,600 eighth-grade students during a digital MR task from the 2017 National Assessment of Educational Progress (NAEP) in mathematics. Utilizing K-means cluster analysis to categorize behavioral and performance patterns, we identified four distinct profiles: Cognitive Offloaders (15% of the sample), Internal Visualizers (55%), External Visualizers (5%), and Non-Triers (25%). Cognitive Offloaders, skilled at minimizing cognitive load by eliminating incorrect options, demonstrated the highest MR accuracy rates at 45%. Internal Visualizers, relying less on digital tools and more …

Location Optimization Strategies For Corn Production And Distribution Towards Sustainable Green Supply Chain, Labiba N. Asha, Lucy G. Aragon, Arup Dey, Nita Yodo

Industrial Engineering Faculty Publications and Presentations

Background: The corn supply chain is vital for food security and economic stability regionally and globally. This study integrates sustainable supply chain management with location optimization to address trade-offs from climate change, economic viability, and environmental impact while assuming the constant social obligation inherent in the supply chain structure. Methods: This study employs a mixed-integer programming (MIP) framework to optimize facility locations in North Dakota, including corn production zones as suppliers and ethanol plants as consumers. Primary objectives include cost minimization and greenhouse gas reduction, enabling the prioritization of economic or environmental goals as per organizational strategies and regulations. This …

Peri-Gondwanan Sediment In The Arkoma Basin Derived From The North: The Detrital Zircon Record Of A Uniquely Concentrated Non-Laurentian Source Signal In The Late Paleozoic, Tyson M. Smith, Marieke Deshesne, Jaime A.M. Hirtz, Glenn R. Sharman, Mark R. Hudson, Brandon M. Lutz, Neil Griffis

Geosciences Faculty Publications and Presentations

During the assembly of Pangea, peri-Gondwanan terranes collided with the eastern and southern margins of Laurentia and brought with them unique detrital zircon U-Pb signatures. Discriminating between individual peri-Gondwanan terranes in the detrital record is difficult due to their similar geologic histories. However, characterization of this provenance is critical for understanding late Paleozoic sediment routing during development of Pangea. Along southeastern Laurentia, in the Arkoma Basin (present-day Arkansas and eastern Oklahoma, southeastern United States), we identified Middle Pennsylvanian (Desmoinesian) strata that exhibit a concentrated peri-Gondwanan detrital zircon signature (e.g., ca. 800–550 Ma). Although several southern peri-Gondwanan terranes (e.g., Maya, Suwannee) …

Aerialformer: Multi-Resolution Transformer For Aerial Image Segmentation, Taisei Hanyu, Kashu Yamazaki, Minh Tran, Roy A. Mccann, Haitao Liao, Chase Rainwater, Meredith Adkins, Jackson Cothren, Hoang Le

Industrial Engineering Faculty Publications and Presentations

When performing remote sensing image segmentation, practitioners often encounter various challenges, such as a strong imbalance in the foreground–background, the presence of tiny objects, high object density, intra-class heterogeneity, and inter-class homogeneity. To overcome these challenges, this paper introduces AerialFormer, a hybrid model that strategically combines the strengths of Transformers and Convolutional Neural Networks (CNNs). AerialFormer features a CNN Stem module integrated to preserve low-level and high-resolution features, enhancing the model’s capability to process details of aerial imagery. The proposed AerialFormer is designed with a hierarchical structure, in which a Transformer encoder generates multi-scale features and a multi-dilated CNN (MDC) …

Hardy Spaces And Canonical Kernels On Quadric Cr Manifolds, Albert Boggess, Jennifer Brooks, Andrew Raich

Mathematical Sciences Faculty Publications and Presentations

R functions on an embedded quadric M always extend holomorphically to M + iΓ_M where Γ_M is the closure of the convex hull of the image of the Levi form. When Γ_M is a closed polygonal cone, we show that the Bergman kernel on the interior of M + iΓ_M is a derivative of the Szegö kernel. Moreover, we develop the L^p Hardy space theory which turns out to be particularly robust. We provide examples that show that it is unclear how to formulate a corresponding relationship between the Bergman and Szegö kernels …

Maximal Estimates For The ∂-Neumann Problem On Non-Pseudoconvex Domains, Phillip S. Harrington, Andrew Raich

Mathematical Sciences Faculty Publications and Presentations

It is well known that elliptic estimates fail for the ∂-Neumann problem. Instead, the best that one can hope for is that derivatives in every direction but one can be estimated by the associated Dirichlet form, and when this happens, we say that the ∂-Neumann problem satisfies maximal estimates. In the pseudoconvex case, a necessary and sufficient geometric condition for maximal estimates has been derived by Derridj (for (0, 1)-forms) and Ben Moussa (for (0, q)-forms when q ≥ 1). In this paper, we explore necessary conditions and sufficient conditions for maximal estimates in the non-pseudoconvex case. We also …

Stimuli-Responsive Phosphate Hydrogel: A Study On Swelling Behavior, Mechanical Properties, And Application In Expansion Microscopy, Yokly Leng, Collin N. Britten, Fatema Tarannum, Kayla Foley, Christopher Billings, Yingtao Liu, Keisha B. Walters

Chemical Engineering Faculty Publications and Presentations

Phosphorus-based stimuli-responsive hydrogels have potential in a wide range of applications due to their ionizable phosphorus groups, biocompatibility, and tunable swelling capacity utilizing hydrogel design parameters and external stimuli. In this study, poly(2-methacryloyloxyethyl phosphate) (PMOEP) hydrogels were synthesized via aqueous activators regenerated by electron transfer atomic transfer radical polymerization using ascorbic acid as the reducing agent. Swelling and deswelling behaviors of PMOEP hydrogels were examined in different salt solutions, pH conditions, and temperatures. The degree of swelling in salt solutions followed CaCl₂ < MgCl₂ < KCl < NaCl with a decrease in swelling rate at higher concentrations until reaching a saturation point. In water, the degree of swelling increased significantly around neutral pH and remained constant at basic pH values. The effects of polymerization conditions, including pH, temperature (30, 40, 50 °C), and MOEP concentration (40, 50, 60% v/v MOEP/H₂O), on the hydrogel swelling behavior in various salt solutions were also investigated. PMOEP hydrogels …

On Weak Solutions And The Navier-Stokes Equations, Aryan Prabhudesai

Mathematical Sciences Undergraduate Honors Theses

In this paper, I will discuss a partial differential equation that has solutions that are discontinuous. This example motivates the need for distribution theory, which will provide an interpretation of what it means for a discontinuous function to be a “solution” to a PDE. Then I will give a detailed foundation of distributions, including the definition of the derivative of a distribution. Then I will introduce and give background on the Navier-Stokes equations. Following that, I will explain the Millennium Problem concerning global regularity for the Navier-Stokes equations and share mathematical results regarding weak solutions. Finally, I will go over …

An Investigation Of The Effect Of Performance Engineered Mixture (Pem) Design On Durability And Air Void Matrix Of Concrete Pavements, Jacob Ortlieb

Graduate Theses and Dissertations

Performance Engineered Mixture (PEM) design is a novel method of creating concrete pavement that is economical achieving desirable performance properties such as durability, strength, and workability. Performance-based design is critical for concrete pavements, so the fresh concrete can be placed without issue and the hardened concrete can withstand deterioration and environmental damage such as freezing and thawing. To achieve economical concrete, PEM utilizes tools such as the tarantula curve for aggregate grading, and the Super Air Meter (SAM) test, providing information regarding the air void matrix while the concrete is fresh. To achieve these properties with less cement will lead …