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Full-Text Articles in Life Sciences

Contrastive Learning For Unsupervised Auditory Texture Models, Christina Trexler Dec 2021

Contrastive Learning For Unsupervised Auditory Texture Models, Christina Trexler

Computer Science and Computer Engineering Undergraduate Honors Theses

Sounds with a high level of stationarity, also known as sound textures, have perceptually relevant features which can be captured by stimulus-computable models. This makes texture-like sounds, such as those made by rain, wind, and fire, an appealing test case for understanding the underlying mechanisms of auditory recognition. Previous auditory texture models typically measured statistics from auditory filter bank representations, and the statistics they used were somewhat ad-hoc, hand-engineered through a process of trial and error. Here, we investigate whether a better auditory texture representation can be obtained via contrastive learning, taking advantage of the stationarity of auditory textures to …


Longitudinal Monitoring Of Tumor Response To Immune Checkpoint Inhibitors Using Diffuse Optical Spectroscopy, Joel Isaac Rodriguez Troncoso Dec 2021

Longitudinal Monitoring Of Tumor Response To Immune Checkpoint Inhibitors Using Diffuse Optical Spectroscopy, Joel Isaac Rodriguez Troncoso

Graduate Theses and Dissertations

Immune checkpoint drugs have completely changed the way people treat metastatic melanoma and non-small-cell lung cancer. While the impacts of these immunological checkpoints and their suppression on T cell function are well characterized, their consequences on the tumor microenvironment are not. In a CT26 mouse colorectal cancer model, we employed diffuse reflectance spectroscopy to track in vivo tumor microenvironmental alterations in response to immune checkpoint inhibitors. On three separate days, animals bearing CT26 tumor xenografts were given anti-PD-L1, anti-CTLA-4, a combination of both inhibitors, and isotype control. Within the first 6 days, monotherapy with either anti-PD-L1 or anti-CTLA-4 resulted in …


Investigating Effects Of Microenvironmental Stress On Cell Metabolism Using Multiphoton Imaging, Lisa Rebello Dec 2021

Investigating Effects Of Microenvironmental Stress On Cell Metabolism Using Multiphoton Imaging, Lisa Rebello

Graduate Theses and Dissertations

Resistance to therapy in cancer is a major cause of poor prognosis in patients. Tumor hypoxia plays an active role in mediating treatment resistance and has been linked to metastases and metastatic potential in cancer. Our research focused on three objectives: i) To understand metabolic effects of chronic and intermittent hypoxia in murine breast cancer cells and its affiliation with metastatic potential ii) To identify the metabolic changes associated with radiation therapy in a panel of radiosensitive and radioresistant human head and neck cancer cells and iii) to monitor the changes in cell metabolism associated with gain of treatment resistance. …


Effect Of Hydrogen Peroxide On Algae And Microcystin In Control And Lake Waters, Tatiana Castillo Hernandez Dec 2021

Effect Of Hydrogen Peroxide On Algae And Microcystin In Control And Lake Waters, Tatiana Castillo Hernandez

Biological and Agricultural Engineering Undergraduate Honors Theses

Cyanobacteria are photo-autotrophic organisms with a worldwide distribution, which can result in Harmful Algal Blooms (HABs) producing toxins. One of the most common strains of cyanobacteria is Microcystis, which produces the most abundant cyanotoxin, microcystin. In this study, we analyzed the effect of H2O2 on algae and microcystin using both lake and reagent grade water. The first objective was to determine the effect of H2O2 on algae and cyanobacteria in lake water that was nutrient enriched. The second objective was to detect the effect of H2O2 at oxidizing microcystin in …


Nanomaterial-Based Biosensors For Detection Of Salmonella Typhimurium And Avian Influenza Virus H5n1 In Poultry, Xinge Xi Jul 2021

Nanomaterial-Based Biosensors For Detection Of Salmonella Typhimurium And Avian Influenza Virus H5n1 In Poultry, Xinge Xi

Graduate Theses and Dissertations

This research focused on developing biosensing method and biosensing device for rapid detection of pathogens in poultry: Salmonella Typhimurium and avian influenza virus H5N1. The first part of the dissertation reports an original research on the development of a portable biosensing device for Salmonella detection. The device was designed and constructed based on a previously developed optical biosensing method, using immuno-magnetic nanoparticles to specifically capture target bacteria, and immuno-quantum dot beads to label the target bacteria for fluorescence detection. All the actions of sample mixing, magnetic separation, and fluorescence detection were controlled automatically in a disposable microfluidic chip in the …


Experimental And Analysis Of Electromagnetic Characterization Of Biological And Non-Biological Materials In Microwave, Millimeter-Wave, And Terahertz Frequency Bands, Nagma Vohra Jul 2021

Experimental And Analysis Of Electromagnetic Characterization Of Biological And Non-Biological Materials In Microwave, Millimeter-Wave, And Terahertz Frequency Bands, Nagma Vohra

Graduate Theses and Dissertations

The goal of this research is to characterize the electromagnetic properties of biological and non-biological materials at terahertz (THz), millimeter-wave, and microwave frequency bands. The biological specimens are measured using the THz imaging and spectroscopy system, whereas the non-biological materials are measured using the microwave and millimeter-wave free-space system. These facilities are located in the Engineering Research Center at the University of Arkansas. The THz imaging system (TPS 3000) uses a Ti-Sapphire laser directed on the photoconductive antennas to generate a THz time domain pulse. Upon using the Fourier Transform, the spectrum of the pulsed THz signal includes frequencies from …


Developing A Lab-Scale Fluidized Bed Dryer System To Enhance Rough Rice Drying Process, Kaushik Luthra Jul 2021

Developing A Lab-Scale Fluidized Bed Dryer System To Enhance Rough Rice Drying Process, Kaushik Luthra

Graduate Theses and Dissertations

For more than half of the world's population, rice (Oryza sativa L.) is a staple meal. However, rice growers encounter difficulties supplying this demand, particularly in developing nations, where rice is susceptible to spoilage if the moisture content is not lowered to a safe level soon after harvest. As a result, traditional drying methods, such as sun drying and natural air drying, are commonly used by rice growers, particularly in underdeveloped nations. However, these procedures are time-consuming and can lead to rice spoilage. On the other hand, fluidized bed drying is a well-established technology that might give rice growers a …


Economic And Ecosystem Impacts Of Gm Maize In South Africa, Kristiina Ala-Kokko May 2021

Economic And Ecosystem Impacts Of Gm Maize In South Africa, Kristiina Ala-Kokko

Graduate Theses and Dissertations

White maize in South Africa is the only staple crop produced on a widespread commercial basis for direct human consumption using genetically modified (GM) cultivars. Using a combined economic and environmental approach, we estimate the total welfare benefits attributable to GM white maize in South Africa for 2001-2018 are $694.7 million. Food security benefits attributable to GM white maize in South Africa also manifest through an average of 4.6 million additional white maize rations annually. To achieve these additional annual rations using conventional hybrid maize, the additional land required would range from 1,088 hectares in 2001 to 217,788 hectares in …


Mapping The Domain Of Rna Helicase Ddx1 That Interacts With The Ns1 Of Influenza A Viruses, Elise Wyatt May 2021

Mapping The Domain Of Rna Helicase Ddx1 That Interacts With The Ns1 Of Influenza A Viruses, Elise Wyatt

Biomedical Engineering Undergraduate Honors Theses

Of the known influenza virus strains, influenza A viruses (IAVs) are the most catastrophic due to their highly contagious nature and possibly life-threatening symptoms. IAVs invade a host cell and enter the nucleus where they use the cell’s nuclear machinery for replication of their viral RNA genome which is then exported to neighboring cells to establish a productive infection. Host pathogen recognition receptors (PRRs) respond to viral infection by signaling the cell to produce type I interferons (IFNs) to fight the foreign invader. Non-structural protein 1 (NS1) of IAVs, a major component in the regulation of viral replication, opposes host …


Light Intensity Control For Plc-Based Hydroponic Demonstration System, Christian Hitt May 2021

Light Intensity Control For Plc-Based Hydroponic Demonstration System, Christian Hitt

Biological and Agricultural Engineering Undergraduate Honors Theses

In order to demonstrate a skill set obtained through the University of Arkansas Biological Engineering, a group of students and I developed a hydroponic system where plants could be grown in a chamber. System parameters such as air quality, irrigation, and lighting were controlled by a Programmable Logic Computer (PLC) and an array of sensors and actuators. Each student focused on a certain aspect of this system, mine being the lighting. Developing this system involved researching the relationship between light intensity and plant growth, designing a system to suspend the lights above the growth chamber, and develop a system to …


Estimating Irrigation In Rice Fields With A Water Balance Approach, Kristen Trinh May 2021

Estimating Irrigation In Rice Fields With A Water Balance Approach, Kristen Trinh

Biological and Agricultural Engineering Undergraduate Honors Theses

Global food production must increase to meet the demand associated with increased population growth, so irrigation water use will continue to rise. Therefore, it is important to monitor water usage particularly when an irrigation flowmeter is unavailable. A field water balance was created for a selection of rice fields in East-central Arkansas under observation in 2018 and 2019. From those, irrigation inputs are deduced from the water balance alone. First, each field had sensors that collected water table level (WTL) data. Next, other water inputs and outputs such as precipitation and evapotranspiration (ET) were collected from two modeled sources. The …


Regression Analysis Of Pacing When Running A Marathon, Hawkin Starke May 2021

Regression Analysis Of Pacing When Running A Marathon, Hawkin Starke

Industrial Engineering Undergraduate Honors Theses

Regression analysis can be an effective way of examining performance in the marathon event. By splitting up the race into segments or in runner terminology “splits” the significance of each segment as it relates to the total finish time can be explored. Because the idea of splits is already ingrained into the minds of runners, it makes intuitive sense to use these as the metrics to define a race. Additionally, marathons generally make participant age and gender date publicly available which can then be used to find trends within specific demographics. This tailors trends to smaller groups of people, making …


Characterization Of Protein Aggregation Using A Solid-State Nanopore Device, Mitu Chandra Acharjee May 2021

Characterization Of Protein Aggregation Using A Solid-State Nanopore Device, Mitu Chandra Acharjee

Graduate Theses and Dissertations

Protein aggregation has been linked to many chronic and devastating neurodegenerative human diseases and is also strongly associated with aging. In the case of neurodegenerative diseases, α, β tubulins and tau proteins dissociate in a neuron cell and aggregate both intra and extra-cellularly. Tau and tubulin aggregations were found as one of the major causes of many neurodegenerative diseases, such as Parkinson’s, Picks, Alzheimer’s, Huntington, and Prion. Finding the state and mechanism of protein aggregation is significant. In this work, tau and tubulin aggregations were detected in ionic solutions using the solid-state nanopore technique. Besides tau and tubulin, aggregations of …


Involvement Of The Ino80 Chromatin Remodeling Complex In Cell Division And Genomic Stability, Ethan Chen May 2021

Involvement Of The Ino80 Chromatin Remodeling Complex In Cell Division And Genomic Stability, Ethan Chen

Biomedical Engineering Undergraduate Honors Theses

Cell division is a vital biological process for growth and development in both single and multi-cellular organisms—whereby the cell must duplicate its organelles and genome in entirety and appropriately distribute the copied contents to the daughter cells. Cells undergo a cycle of two distinct phases: interphase and mitosis. During interphase, the cell replicates its genomic DNA (in the form of chromosomes) located within the nucleus. DNA replication is carried out in a euchromatin state, where the chromosome structure is loose and easily accessible by DNA polymerase and other replication enzymes. Upon the completion of replication, chromatin is condensed into highly …


Journal Of The Arkansas Academy Of Science - Volume 75, 2021, Academy Editors Jan 2021

Journal Of The Arkansas Academy Of Science - Volume 75, 2021, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.


Business Meeting Report (Secretary's And Treasurer's Report), Academy Editors Jan 2021

Business Meeting Report (Secretary's And Treasurer's Report), Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.