Life Sciences Commons^™

Musculoskeletal Modeling Analysis Of Knee Joint Loading During Uphill And Downhill Waling In Patients With Total Knee Replacement, Tanner A. Thorsen

Doctoral Dissertations

The purposes of these studies were to determine differences in total (TCF), medial (MCF) and lateral (LCF) tibiofemoral compartment compressive forces and related muscle forces between limbs (replaced, non-replaced, and control), and different slopes during uphill [0° (level), 5°, 10°], and downhill [0° (level), 5° 10°] using statistical parametric mapping (SPM). Static optimization was used to determine muscle and compressive forces for 9 patients with total knee arthroplasty (TKA) and 9 control participants during walking trials. Total , loading-response, and push-off TCF impulse were calculated. A 3×3 [Limb (replaced, non-replaced, control] × Slope (0°, 10°, 15°)] SPM[F] repeated measures ANOVA …

Epigenetic Mechanisms Governing Plant Growth, Development, And Responses To Nematode Parasitism, Meredith M. Bennett

Doctoral Dissertations

Epigenetic mechanisms, including histone and DNA methylation and microRNAs, play key roles in mediating transcriptional changes during plant development and stress responses. However, how these interconnected epigenetic components regulate gene expression in a spatiotemporal fashion remains partially known. Here, I generated 15 transgenic Arabidopsis GUS reporter lines for genes involved in DNA methylation and demethylation pathways. The spatiotemporal expression patterns of these genes were profiled in various plant organs during development, exogenous phytohormone response, and plant-parasitic nematode pathogenesis. The analyses revealed unique and overlapping expression patterns in roots, shoots, and reproductive organs, emphasizing the importance of a DNA methylation—demethylation equilibrium. …

Social Context Influences On Behavior Of Carolina Chickadees, Brittany A. Coppinger

Doctoral Dissertations

This dissertation assesses fundamental social factors that drive variation in calling and other behaviors of experimental flocks of Carolina chickadees. Specifically, I tested how group member familiarity and group composition affected individual behavior. In addition, I performed a direct experimental test of the Social Complexity Hypothesis for Communicative Complexity, which states that groups that are more socially complex will communicate with greater signal complexity than groups that are less social complex. I consider complexity to be a combination of three factors: the number of parts in a system, the variation among the parts, and the variation in the way those …

Investigation Of Interactions Between 1,3 Dialkyl Imidazolium Ionic Liquids And Lignocellulosic Polymers, Aparna Annamraju

Doctoral Dissertations

Lignocellulosic biomass is a potential energy source for fuels, chemicals and materials production in a sustainable manner. A network of covalent and non-covalent bonds between the three main polymers of biomass, i.e., cellulose, hemicellulose and lignin, results in a compact structure that is resistant to chemical and biological attacks and therefore challenging for the efficient utilization of lignocellulosic biomass. Ionic liquids (ILs) have been reported to disrupt the bonds between these polymers and dissolve biomass at temperatures below 100 ˚C. Research through the years has shown that biomass pretreatment with IL brings out the selective dissolution of biomass polymers and …

Using A Cognitive Behavioral Approach In Individual Counseling With Patients Undergoing Bariatric Surgery, Nina Marie Ditommaso

Doctoral Dissertations

Morbid obesity is linked to physical and psychological well-being. Bariatric surgery has shown tremendous success with rapid weight loss in the patient population with morbid obesity. These patients experience issues with weight regain post-surgery, which can be linked to psychological and social factors. Despite this, mental health counseling is rarely offered in bariatric surgery programs. The primary investigator used a six-session Cognitive Behavioral Therapy (CBT) approach in individual counseling with patients following bariatric surgery. The primary investigator used a single case research design to treat four participants. The primary investigator measured the effectiveness of a six-session CBT treatment, assessing for …

Novel Insights Into The Role Of Pyruvate Kinase M2 In Podocyte Homeostasis And Function, Mohammed Alquraishi

Doctoral Dissertations

Background: Renal diseases are major health concerns and among the top ten leading causes of death in the US. A large number of these diseases are characterized by deterioration in glomerular structure and function, leading to reduced filtration capacity and proteinuria. Glomerulus podocytes are epithelial cells that maintain glomerular integrity and act as a defense mechanism against proteinuria. Recent advances in renal research suggested a novel role of glycolysis and its related enzymes, pyruvate kinase M2 (PKM2) in particular, in the progression of renal diseases. However, the precise role of PKM2 in podocyte homeostasis and its contribution to glomerular function …

Synthetic Heterosynaptic Plasticity Enhances The Versatility Of Memristive Systems Emulating Bio-Synapse Structure And Function, William T. Mcclintic

Doctoral Dissertations

Memristive systems occur in nature and are hallmarked via pinched hysteresis, the difference in the forward and reverse pathways for a given phenomenon. For example, neurons of the human brain are composed of synapses which apply the properties of memristance for neuronal communication, learning, and memory consolidation. Modern technology has much to gain from the characteristics of memristive systems, including lower power operation, on-chip memory, and bio-inspired computing. What is more, a relationship between memristive systems and synaptic plasticity exists and can be investigated focusing on homosynaptic and heterosynaptic plasticity. Where homosynaptic plasticity applies to interactions between neurons at a …

Evolution And Resurrection Ecology Of A Foundational Coastal Marsh Plant, Jennifer L. Summers

Doctoral Dissertations

Stratified storage of dormant seeds in soil can result in natural archives useful for studying evolutionary responses to environmental change. However, few studies leverage soil-stored seed banks as natural archives, in part because of concerns over attrition, bias, and sediment mixing. Here, I examine the persistent seed bank of Schoenoplectus americanus, a foundational brackish marsh sedge, to a) determine whether it can serve as a resource for reconstructing demographic and population genetic/genomic variation, b) whether and how evolution may be occurring across a century. After extracting seeds from radionuclide-dated soil cores taken across the Chesapeake Bay, I “resurrected” age …

The Role Of Med31 And Med12 In Directing Adipogenesis Of Human Adult-Derived Mesenchymal Stem Cells, Joseph Straub

Doctoral Dissertations

Selective gene expression is crucial in maintaining the self-renewing and multipotent properties of stem cells. Mediator is a large, evolutionarily conserved, multisubunit protein complex that modulates gene expression by relaying signals from cell type-specific transcription factors to RNA polymerase II. In humans, this complex consists of 30 subunits arranged in four modules: head, middle, tail, and kinase. In our introduction, we show the state of the field of Mediator study with a focus on the critical kinase module. In the following chapters, we used siRNA knockdowns to investigate the roles of the highly-conserved core subunit MED31 and the kinase module …

Glial Endothelial Brain Cell Co-Cultures For Testing Signaling Response And Delivery Of Novel Materials Across Blood Brain Barrier, Neela Prajapati

Doctoral Dissertations

The brain accounts for 20% of overall energy metabolism in the body though it just comprises 2% of the total body mass but has a limited capacity of storing energy unlike other critical organs in the body such as the heart and liver. This energy along with oxygen and nutrients is supplied by cerebral blood flow (CBF), any interruption of which can cease the brain function within seconds with a potential irreversible neuronal injury, within minutes. Vascular cells along with astrocytes and neurons are a part of a recently developed concept known as the Neurovascular Unit responsible for Neurovascular coupling …

Ecogeographical And Micromorphological Differentiation Between Selfing And Outcrossing Sister Species, Alannie-Grace Grant

Doctoral Dissertations

Since their emergence during the Cretaceous period, Angiosperms, or flowering plants, have achieved incredible success on land, colonizing an extensive range of environmental conditions and creating the structure of the Earth’s ecosystems. As they have adapted to these conditions, Angiosperms diverged in their niche breadth, morphological, physiological, biochemical, and phenological traits and evolved into the plant species known today. Some of the diversification within Angiosperm species is attributed to the adaptive evolution of floral traits that facilitate cross-fertilization by attracting and rewarding animal pollinators who transport their pollen or reductions in these traits to maximize self-fertilization.

In this dissertation, I …

Preserving The Native Environment Of Photosystem I Within Styrene Maleic Acid Lipid Particles (Smalps) For Applications In Biohybrid Solar Devices., Nathan G. Brady

Doctoral Dissertations

In order to meet the growing demand for energy in our society and the environmental need to reduce carbon dioxide pollution in our atmosphere, it is imperative that we devise a scalable strategy to convert sunlight to electricity without the use of Earth-limited resources and rare elements. Biohybrid solar devices (BHSDs), described here, which incorporate photosynthetic proteins onto electrode surfaces to facilitate the capture and conversion of sunlight to electricity offer such a strategy, though the efficiencies of these devices remain very low at present. This work is focused on the innovation of retaining the native environment of photosystem I …

Regulation Of Plasmodesmata By Specialized Metabolites Glucosinolates In Arabidopsis Thaliana, Jessica C. Fernandez

Doctoral Dissertations

Communication is an essential component to all living organisms. In

plants, the additional cell wall surrounding each cell adds a layer of complexity

not observed in animals. To overcome the literal wall separating cells, plants

have evolved specialized pores to connect adjacent cells. Plasmodesmata (PD)

allow plants to have a continuous cytoplasm between cells. Although

plasmodesmata may appear simple and lack regulation, their structural

components and their regulatory machinery is complex and not well understood.

Organelle-to-nucleus-to-plasmodesmata signaling (ONPS) have been worked as

a leading model for a possible regulatory mechanism. Many of the details of

organelle-to-nucleus retrograde signaling pathways have …

Using Multi-Omics Approaches To Study Flowering Time And Fruit Development In Perennial Fruit Species, Jiali Yu

Doctoral Dissertations

Perennial fruiting plants coordinate their reproductive activities with seasonal changes in the temperate climates, with a pattern of bud set, dormancy establishment, fulfillment of chilling, flowering, fruit set, and fruit ripening. These processes have been optimized for the production of orchard plants that reliably produce quality fruit for human consumption. The understanding of molecular controls of dormancy in fruit trees has grown rapidly in the past decade, however, the complex mechanisms remain largely unknown. This dissertation presents my findings on genetic and epigenetic changes in Prunus species from dormancy to flowering using transcriptomics and epigenomics approaches. First, I compared the …

Bone Morphogenetic Proteins Modulate Mast Cell Responses During Inflammation, Jane S. Woodrow

Doctoral Dissertations

Chronic inflammatory conditions can lead to detrimental health conditions that become difficult to manage and treat. Ultimately treatment requires modulation of the critical cell types involved in pathology in order to achieve homeostasis. Mast cells, a type of innate immune cell located at areas of high antigen load, are commonly thought of as primarily pro-inflammatory, but are becoming increasingly recognized in other roles, such as wound healing, anti-inflammatory actions, and homeostatic functions. In this study we investigate the role of mast cell subtypes and inflammatory mechanisms via in vitro assays using mouse and human mast cells, as well as relate …

Data Driven Models Of Hemlock Woolly Adelgid Impacts And Biological Control, Hannah M. Thompson

Doctoral Dissertations

We present two models of the Adelges tsugae, the hemlock woolly adelgid, an invasive insect pest of Tsuga canadensis, eastern hemlock, in the eastern United States. An A. tsugae infestation often results in the death of T. canadensis within years, and has caused significant changes to hemlock forests. We construct two models composed of systems of ordinary differential equations with time dependent parameters to represent seasonality. The first model captures the coupled cycles in T. canadensis health and A. tsugae density. We use field data from Virginia to develop the model and to perform parameter estimation. The mechanisms …

Fungicide Sensitivity Screening Of Corynespora Cassiicola In Us Soybean And Cotton, Tyler Miles Smith

Doctoral Dissertations

Target spot, caused by the fungus Corynespora cassiicola, is a foliar disease of cotton and soybean. Target spot has become a disease of concern in soybean and cotton production systems. Data for fungicide sensitivity and understanding potential impact on yield is lacking for C. cassiicola. Fungicide resistance is also a concern in C. cassiicola with the increase in resistant pathogens in soybean. With the lack of knowledge about baseline fungicide sensitivity and the concern of fungicide resistance the objectives of this study were: (i) to evaluate fungicide products and mixes in small plot soybean and cotton trials, (ii) …

Caprine Γδ T Cell Biology, Alehegne W. Yirsaw

Doctoral Dissertations

CAPRINE gd T CELL BIOLOGY AUGUST 2020 ALEHEGNE W YIRSAW, DVM, ADDIS ABABA UNIVERSITY, ETHIOPIA MSC., ADDIS ABABA UNIVERSITY, ETHIOPIA PHD., UNIVERSITY OF MASSACHUSETTS AMHERST DIRECTED BY: PROFESSOR CYNTHIA L BALDWIN Goats are important food animals and are disseminated globally. Their productivity is impacted by infectious diseases thus impacting the livestock owners and the community. γδ T lymphocytes or T cells have vital roles in immune responses in mammals and thus we identified information gaps regarding these cells in goats. We used genome annotation, PCR amplification of genomic DNA and cDNA, and Sanger and PacBio sequencing for this research to …

Dynamic Evolution In The Leucine-Rich Repeat Receptor-Like Kinase (Lrr-Rlk) Family Of Receptors, Jarrett Man

Doctoral Dissertations

Cells in multicellular organisms must gauge their environmental conditions, including neighboring cells, during development. In plants, the Leucine-Rich Repeat Receptor-like Kinases (LRR-RLKs) encode a family of membrane-bound receptors that transduce such cell-to-cell signals and are required for many aspects of plant development. Very little is known about the function of most of these genes, and the evolutionary history of the family is difficult to infer because of its size and complexity. Several factors contribute to this difficulty, including genetic redundancy, challenging bioinformatic detection, exceptionally large family size, and high copy number variation among species. In this dissertation, I characterize some …

Physiological Constraints, Mechanisms, And Mineral Transformations Of Iron Reduction In Hyperthermophilic Crenarchaea, Srishti Kashyap

Doctoral Dissertations

Dissimilatory iron reduction by hyperthermophilic archaea occurs in many geothermal environments and typically relies on microbe-mineral interactions that transform various iron oxide minerals. However, the kinds of iron oxides that can be used, growth rates, extent of iron reduction, and the mineral transformations that occur due to this metabolism are poorly understood. This dissertation improves our fundamental understanding of the physiological mechanisms and mineral transformations of hyperthermophilic iron reduction using two model crenarchaea, Pyrodictium delaneyi and Pyrobaculum islandicum. Using growth yields and metabolite production rates, we demonstrated that a broad range of Fe(III) (oxyhydr)oxides of variable thermodynamic stability was …

Mental Fatigue: Examining Cognitive Performance And Driving Behavior In Young Adults, Abigail F. Helm

Doctoral Dissertations

Mental fatigue causes an increase in task-based EEG theta and alpha power and a decrease in performance (for a review, see Tran et al., 2020). However, little is known about the emergence of mental fatigue in resting state EEG recordings and whether the progression of mental fatigue over time is influenced by individual differences. The current dissertation examined the utility of resting state EEG as a measure of mental fatigue by testing whether EEG power changed in young adults over the course of a cognitively demanding battery of tasks. The current dissertation also tested how this measure of mental fatigue …

Interactions Between Titanium Dioxide Nanoparticles (Nps) And Mucin, . Boimin

Doctoral Dissertations

Titanium dioxide nanoparticles (TiO₂ NPs) are widely used in many food, consumer, and industrial products. However, little is known about the overall effects of TiO₂ NPs on the environment or human health. In order to elucidate the fate, transformation, transport, and toxicological impact of TiO₂ NPs, a better understanding is needed of how the physicochemical properties of TiO₂ NPs (e.g. size, charge, curvature, hydrophobicity, and surface functionality) interact with their microenvironments (e.g. pH, temperature, bile acids, microbiome, enzymes, surface-active components, and biopolymers). Living organisms including humans have a natural mechanism to protect themselves from physical, biological, …

An Emg Optimization Model Of The Kinetic Demands On The Lower Back During Asymmetrical Gait And Load Carriage, Jacob J. Banks

Doctoral Dissertations

Gait asymmetries are associated with a high incidence of lower back pain (LBP). Although there are several causes of gait asymmetry (i.e. amputation, injury, or deformities), lower back kinetic demands have not been quantified and suitably compared due to experimental limitations in these clinical populations. Further, the impact of gait asymmetry on lower back demands during carrying tasks has not been established. This dissertation addressed these issues by artificially and safely inducing gait asymmetry in healthy able-bodied participants during walking and carrying tasks. LBP risk was assessed by L5/S1 vertebral joint force levels estimated with an OpenSim musculoskeletal model of …

Substrate Selection In Endoplasmic Reticulum Protein Quality Control, Ben Adams

Doctoral Dissertations

Protein folding and maturation is a complex and error-prone process. Errors in this process may lead to deleterious effects ranging from non-functional single proteins to large-scale protein aggregation leading to cell death. It is essential for cellular function that protein misfolding does not occur unchecked, and therefore numerous chaperone systems exist within the cell. For the thousands of proteins which traffic through the secretory pathway, the primary site of folding and maturation is the endoplasmic reticulum (ER). Multiple chaperone pathways within the ER, generally termed ER protein quality control, must support the proper maturation process of these thousands of substrates. …

Design And Biomechanical Evaluation Of A Clutch-Based Energy Storage And Release Assistive Knee Brace, Ericber Jimenez Francisco

Doctoral Dissertations

Knee osteoarthritis (OA) is a serious degenerative disease affecting over 240 million people around the world. The most disabling symptoms are joint pain, joint stiffness, and reduction in joint functionality. Medial compartment knee OA is the most common case of unicompartmental knee OA, and pain and progression have been associated with tibiofemoral alignment in early to moderate knee OA patients, mainly due to its association with knee loading as measured by knee adduction moment (KAM) and tibiofemoral contact forces (KCF). Valgization knee braces have been developed to correct the malalignment at the tibiofemoral joint, but they have no direct effect …

An Investigation On The Regulation Of The Tweak–Fn14–Nf-Kb Pathway, Jawahar Khetan

Doctoral Dissertations

“Dysregulation of inflammatory pathways is strongly implicated in cancers and autoimmune diseases. The most consequential of these pathways involves the nuclear translocation of NF-kB, a transcription factor that induces the transcription of multiple proteins associated with cell survival, inflammation, proliferation and death. It is activated when the fibroblast growth factor-inducible 14 kDa protein (Fn14), a trimeric receptor recruits its ligand, TWEAK. Studies have shown that Fn14 is over-expressed in many tumors, the aggressiveness of which is often correlated with the degree of upregulation. Furthermore, TWEAK-Fn14 activation has been shown to result in persistent NF-kB activation. Using a mechanistic model of …

Critical Behavior In Evolutionary And Population Dynamics, Stephen Walter Ordway

Doctoral Dissertations

“This study is an exploration of phase transition behavior in evolutionary and population dynamics, and techniques for predicting population changes, across the disciplines of physics, biology, and computer science. Under the looming threat of climate change, it is imperative to understand the dynamics of populations under environmental stress and to identify early warning signals of population decline. These issues are explored here in (1) a computational model of evolutionary dynamics, (2) an experimental system of decaying populations under environmental stress, and (3) a machine learning approach to predict population changes based on environmental factors. Through the lens of critical phase …

Exposure Assessment Of Emerging Contaminants: Rapid Screening And Modeling Of Plant Uptake, Majid Bagheri

Doctoral Dissertations

"With the advent of new chemicals and their increasing uses in every aspect of our life, considerable number of emerging contaminants are introduced to environment yearly. Emerging contaminants in forms of pharmaceuticals, detergents, biosolids, and reclaimed wastewater can cross plant roots and translocate to various parts of the plants. Long-term human exposure to emerging contaminants through food consumption is assumed to be a pathway of interest. Thus, uptake and translocation of emerging contaminants in plants are important for the assessment of health risks associated with human exposure to emerging contaminants. To have a better understanding over fate of emerging contaminants …

Multimodal Neuroscience Data Modeling And Inference, Sima Azizi

Doctoral Dissertations

“Mathematical models can be combined with deep learning and machine learning methods to provide new insights in neuroscience. The field of neuroscience is characterized by rich datasets that include fluid biomarkers, EEG signals, and advanced neuroimages. Recent advances in natural language processing have led to the opportunity to gain additional insights from rapidly growing text databases as well as electronic health records. In this research, we focus on applying computational intelligence methods to the analysis of three different complex data sources: blood levels of disease biomarkers, EEG signals from schizophrenic patients, and disease phenotypes encoded in electronic health records. First, …

High Throughput Analysis To Study Emerging Pollutants And Nanoparticle Fate In Biological Systems, Xiaolong He

Doctoral Dissertations

”The increasing applications of emerging and fugitive contaminants (EFCs) and engineered nanoparticles (ENPs) attract significant research interest for their potential risks to human health and the environment. In order to assess the health risks of these emerging contaminants, rapid and reliable analytical methods to measure the concentrations and fates of these contaminants are imperative. This dissertation focuses on the developments of advanced analytical methods and their applications to study those emerging contaminants in crop plant and simulated gastric fluid (SGF). Three types of mass spectrometry based methodologies have been developed, one is freeze-thaw/centrifugation extraction followed by high performance liquid chromatography …