Life Sciences Commons^™

The Development Of A Traumatic Brain Injury Bioreactor, Zachery Heller

Graduate Theses and Dissertations

Approximately 1.7 million Americans experience a traumatic brain injury (TBI) each year. Concussive injuries are a subset of TBI in which blows to the head cause the brain to collide against the interior of the skull. Damage to the neurons, supporting cells, and surrounding extra cellular matrix resulting from these collisions can lead to permanent physical, cognitive, and psychological impairment. We believe the prevalence and clinical significance of concussive injures warrants research investment. To study brain injury following TBI, in vivo models have been the gold standard for TBI experiments. Although a valuable research alternative, animals are expensive, raise ethical …

Monodentate, Bidentate And Photocrosslinkable Thiol Ligands For Improving Aqueous Biocompatible Quantum Dots, Hiroko Takeuchi

Graduate Theses and Dissertations

Water-soluble Quantum Dots (QDs) are highly sensitive fluorescent probes that are often used to study biological species. One of the most common ways to render QDs water-soluble for such applications is to apply hydrophilic thiolated ligands to the QD surface. However, these ligands are labile and can be easily exchanged on the QD surface, which can severely limit their application. As one way to overcome this limitation while maintaining a small colloidal size of QDs, we developed a method to stabilize hydrophilic thiolated ligands on the surface of QDs through the formation of a crosslinked shell using a photocrosslinking approach. …

Environmental Tradeoffs In Bioenergy Production And Agricultural Practices, Alicia Lynn English

Open Access Dissertations

The focus of this dissertation is the environmental tradeoffs of stover removal within the Corn Belt. The environmental tradeoffs considered are mainly concerned with managing soil erosion and soil quality. The analysis layers soil characteristics, management strategies and per acre costs using an integrated RUSLE2/WEPS model and an economic optimization model to illuminate a lower bound supply response. Different assumptions were tested in regards to sustainability, prices, and market integration for five states and 18,760 soil types throughout the Corn Belt. Sustainability was defined to limit soil erosion from wind and water to 5 tons/acre/year and the soil organic matter …

Effects Of Hearing Aid Amplification On Robust Neural Coding Of Speech, Jonathan Daniel Boley

Open Access Dissertations

Hearing aids are able to restore some hearing abilities for people with auditory impairments, but background noise remains a significant problem. Unfortunately, we know very little about how speech is encoded in the auditory system, particularly in impaired systems with prosthetic amplifiers. There is growing evidence that relative timing in the neural signals (known as spatiotemporal coding) is important for speech perception, but there is little research that relates spatiotemporal coding and hearing aid amplification.

This research uses a combination of computational modeling and physiological experiments to characterize how hearing aids affect vowel coding in noise at the level of …

Effects Of Dip-Coated Films On The Properties Of Implantable Intracortical Microelectrodes, Salah Sommakia

Open Access Dissertations

The successful clinical use of implantable intracortical microelectrodes (ICMs) to treat certain types of deafness, blindness, and paralysis is limited by a reactive tissue response (RTR) of the brain. This RTR culminates in the formation of a tight glial scar and a loss of neuronal density around implanted ICMs, and is accompanied by a decrease in signal to noise ratio and an increase in impedance. While no comprehensive mechanistic understanding of the underlying biology is currently agreed upon in the field, a general consensus exists around a highly volatile acute RTR phase. During this acute phase, the electrical properties of …

Ozonation Systems As A Non-Chemical Alternative For Stored Grain Protection, Carlos A. Campabadal

Open Access Dissertations

The use of ozone as a non-chemical alternative in stored grain protection was studied by conducting scale-up demonstrations using a fixed bed ozonation system and developing a semi-continuous counterflow and a continuous flow ozonation treatment system. The objectives of this research were to determine the efficacy of ozonation to control insect pests without affecting end-use quality; to prove the concept of the semi-continuous counterflow ozonation system to ozonate grain at a faster rate and quantify its effect on mold growth reduction; to evaluate the efficacy of a modified screw conveyor for pest control by treating grain in a continuous-flow ozonation …

Algae To Propellants: Biosynthesis Of 1,2-Propanediol From Algal Derived Sugars, Lauren Rachelle Merriman

Graduate Theses and Dissertations

Propylene glycol dinitrate (PGDN) is an important component used in the formulation of energetic materials. A renewable, environmentally-friendly and effective production technique for the production of 1,2-propanediol, an important precursor to PGDN, is desired. While fermentation of 1,2-propanediol has been achieved, it suffers from major limitations such as expensive feed sugars and relatively low yields. It is hypothesized that algae sugars could serve as a feedstock for the microbial synthesis of 1,2-propanediol, thereby reducing production costs and enhancing sustainability.

Algal biomass produced from an Algal Turf Scrubber® has proven to have significant potential as a source of fermentable materials. However, …

A Mathematical Model And Numerical Method For Thermoelectric Dna Sequencing, Liwei Shi

Doctoral Dissertations

DNA sequencing is the process of determining the precise order of nucleotide bases, adenine, guanine, cytosine, and thymine within a DNA molecule. It includes any method or technology that is used to determine the order of the four bases in a strand of DNA. The advent of rapid DNA sequencing methods has greatly accelerated biological and medical research and discovery. Thermoelectric DNA sequencing is a novel method to sequence DNA by measuring the heat that is released when DNA polymerase inserts a deoxyribonucleoside triphosphate into a growing DNA strand. The thermoelectric device for this project is composed of four parts: …

Biodiesel Transesterification Byproducts As Soil Amendments, Solomon Parker

Graduate Theses and Dissertations

For every ten kilograms of biodiesel that is produced from the transesterification of vegetable oil, approximately 1 kg of glycerol is produced as a byproduct. Also known as glycerin, it is a chemical used in many products including cosmetics, foods, and desiccants. However, the crude glycerol created during biodiesel production is tainted with potassium hydroxide and methanol making it unsuitable for commercial use without costly refinement. With increase in production of biodiesel driven by rising fuel prices, the market has become glutted with glycerol and it is on the threshold of becoming a waste product. Common methods for disposing glycerol …

Using The Ceres-Maize Model To Create A Geographically Explicit Grid Based Estimate Of Corn Yield Under Climate Change Scenarios, Ryan Zachary Johnston

Graduate Theses and Dissertations

The CERES-Maize model was evaluated in its capacity to predict both regional maize yield and water use within the United States Department of Agriculture (USDA) Economic Research Service (ERS) Region 1 between the years 1997-2007. A grid based, geospatially explicit method was developed to express the various rainfed and irrigated maize cultivars grown across the region. Overall, the calibrated model compared well for both physiological and yield parameters, producing significant linear relationships (p

The calibrated and validated CERES-Maize model was used to predict potential evapotranspiration and yield under three IPCC weather scenarios for the year 2050 to evaluate crop production …

Investigations Toward Tunability Of Mechanical, Thermal, And Impact Properties Of Thiol-Ene Networks For Novel High Energy Absorbing Materials, Olivia Devon Mcnair

Dissertations

The UV polymerization of thiols with electron rich alkenes is a highly resourceful reaction that has been utilized by scientists within various disciplines to produce an even more versatile display of applications. This dissertation focuses on a newer application, thiol-ene network (TEN) materials for energy absorption devices. TEN networks display a host of positive polymer properties such as low stress, high optical clarity and uniformity, but they also suffer from unfavorable mechanical properties such as low toughness and elongation at break. The poor mechanical properties demonstrated by TENs prohibit them as choice materials for applications requiring thicker material forms, including …

Expression, Production, And Purification Of Novel Therapeutic Proteins, Mckinzie Shea Fruchtl

Graduate Theses and Dissertations

Interest in the production of recombinant proteins consisting of collagen binding domain (CBD) fused to a bioactive material has increased due to the targeting/attachment capabilities of CBD. For example, CBD fusions can be applied to the reversing of bone density loss and the repair of the eardrum, specifically, by choosing an appropriate fusion partner (parathyroid hormone or epidermal growth factor). The production of CBD fusions was examined using batch and fed-batch culturing of Escherichia coli to express the fusion proteins, and affinity chromatography to isolate the final product.

Different medium formulations, feeding strategies, and induction methods were tested in order …

Measuring The Energy Required To Dry Rice In Commercial Rice Dryers, Maria Alejandra Billiris

Graduate Theses and Dissertations

The objective of this research was to quantify and assess the energy use and efficiency of commercial cross-flow dryers when drying rice using a range of drying and ambient conditions. First, equations that predict the theoretical energy required to dry rice from any given initial moisture content to a desired final moisture content were developed for several rice cultivars using a semi-theoretical approach to obtain a basis for comparison to calculate energy efficiency. Theoretical energy requirements, expressed as the energy required per unit mass of water removed, increased exponentially as initial moisture content decreased. Additionally, medium-grains required more energy to …

The Geometry And Sensitivity Of Ion-Beam Sculpted Nanopores For Single Molecule Dna Analysis, Ryan Connor Rollings

Graduate Theses and Dissertations

In this dissertation, the relationship between the geometry of ion-beam sculpted solid-state nanopores and their ability to analyze single DNA molecules using resistive pulse sensing is investigated. To accomplish this, the three dimensional shape of the nanopore is determined using energy filtered and tomographic transmission electron microscopy. It is shown that this information enables the prediction of the ionic current passing through a voltage biased nanopore and improves the prediction of the magnitude of current drop signals when the nanopore interacts with single DNA molecules. The dimensional stability of nanopores in solution is monitored using this information and is improved …

Qcm Aptasensor For Rapid And Specific Detection Of Avian Influenza Virus, Luke Brockman

Graduate Theses and Dissertations

There has been a need for rapid detection of avian influenza virus (AIV) H5N1 due to it being a potential pandemic threat. Most of the current methods, including culture isolation and PCR, are very sensitive and specific but require specialized laboratories and trained personnel in order to complete the tests and are time-consuming. The goal of this study was to design a biosensor that would be able to rapidly detect AIV H5N1 using aptamers as biosensing material and a quartz crystal microbalance (QCM) for transducing method. Specific DNA aptamers against AIV H5N1 were immobilized, through biotin and streptavidin conjugation, onto …

Modulation Of Cell-Matrix Interaction For Cryopreservation Of Engineered Tissue, Angela Christine Seawright

Open Access Theses

Long term preservation of functional engineered tissues can significantly advance tissue engineering industry and regenerative medicine. Several preservation techniques have been proposed and investigated for this purpose, and cryopreservation is a leading candidate. While tissues are cryopreserved, ice forms in both the extracellular and intracellular spaces and causes freezing-induced spatiotemporal deformation of the tissue. During this process the cells undergo dehydration by the freezing-induced osmotic pressure difference and mechanical deformation, transmitted through cell-extracellular matrix adhesions. However, the significance and interaction of these cellular level transport and mechanics processes are not well understood. Therefore, this study aims to establish mechanistic understanding …

Modeling Tools For Conformal Orthotic Devices, Steven David Riddle

Open Access Theses

The purpose of this thesis is to advance the design of conformal orthotic devices through the development of two modeling tools to address knowledge gaps in the field.

The field of human orthotics has been continually troubled by identifying successful methods of harnessing devices to the body. Past orthotics have utilized a rigid framework with minimal degrees of freedom (DOFs) driven by hard actuators attached to the body at select anchor points. Many devices design the structure and anchor points such that they reduce the degrees of freedom of a targeted joint, limiting the user's mobility and often causing the …