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Title: Intraoperative blood glucose management : a quality improvement project
Creator: Baker, Jake (Nurse)
Date: 2022
Collection: Doctor of Nursing Practice Projects
Description: Perioperative hyperglycemia is associated with a myriad of post-surgical complications including an increased incidence of surgical site infections and prolonged hospital stays. The use of an evidence-based perioperative blood glucose management protocol reduces morbidity and mortality in adult patients undergoing surgical procedures. The project team describes a cost-effective quality improvement initiative aimed at improving protocol adherence by integrating an easy-to-use protocol...
Show morePerioperative hyperglycemia is associated with a myriad of post-surgical complications including an increased incidence of surgical site infections and prolonged hospital stays. The use of an evidence-based perioperative blood glucose management protocol reduces morbidity and mortality in adult patients undergoing surgical procedures. The project team describes a cost-effective quality improvement initiative aimed at improving protocol adherence by integrating an easy-to-use protocol algorithm, order sets, and practice reminders into an existing electronic health record system.
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Title: Improving perioperative nausea and vomiting prophylaxis protocol compliance
Creator: Franz, Allison
Date: 2022
Collection: Doctor of Nursing Practice Projects
Description: Postoperative nausea and vomiting (PONV) is a significant concern in anesthesia practice. Evidence-based guidelines have sought to provide recommendations on identifying patients at risk for PONV and mitigating its effect with multimodal antiemetic strategies. An anesthesia department within a large teaching hospital uses the Anesthesiology Performance Improvement and Report Exchange guidelines to identify and manage patients at risk for PONV. These guidelines are intended to integrate best...
Show morePostoperative nausea and vomiting (PONV) is a significant concern in anesthesia practice. Evidence-based guidelines have sought to provide recommendations on identifying patients at risk for PONV and mitigating its effect with multimodal antiemetic strategies. An anesthesia department within a large teaching hospital uses the Anesthesiology Performance Improvement and Report Exchange guidelines to identify and manage patients at risk for PONV. These guidelines are intended to integrate best practices into anesthetic care and improve overall surgical outcomes. The anesthesia department currently has a PONV protocol in place that aligns with the guidelines but has not achieved their compliance benchmark. This evidence-based quality improvement project describes interventions proposed to increase compliance with the PONV protocol. To address poor PONV compliance, an anonymous survey was developed to assess anesthesia provider's current familiarity with the new PONV guidelines and identify misconceptions. A visual feedback system was implemented using a preliminary confidential list that anonymizes staff. This allowed individual providers to identify their own performance in relation to their peers in a non-punitive way. The results of this quality improvement project demonstrate that the proposed interventions increased departmental compliance.
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Title: Development and implementation of an enhanced recovery after surgery protocol for women undergoing a mastectomy
Creator: Braun, Michael
Date: 2022
Collection: Doctor of Nursing Practice Projects
Description: This evidenced-based practice initiative includes the development and implementation of an evidence-based enhanced recovery after surgery (ERAS) guideline with a specific focus on the incidence of postoperative nausea and vomiting (PONV) and opioid administration in the postoperative setting. The clinical question was in adult women, age 18 years or greater, undergoing a mastectomy procedure, does the implementation of an ERAS guideline lower the incidence of PONV and reduce morphine...
Show moreThis evidenced-based practice initiative includes the development and implementation of an evidence-based enhanced recovery after surgery (ERAS) guideline with a specific focus on the incidence of postoperative nausea and vomiting (PONV) and opioid administration in the postoperative setting. The clinical question was in adult women, age 18 years or greater, undergoing a mastectomy procedure, does the implementation of an ERAS guideline lower the incidence of PONV and reduce morphine milligram equivalent (MME) requirements in a post-anesthesia care unit (PACU)? Patients undergoing breast cancer surgery have multiple risk factors and the reported incidence of PONV reaches up to 80%. Over half of post-surgical breast cancer patients develop neuropathic pain syndromes. A mastectomy ERAS guideline was developed then applied to the perioperative course of 22 patients. It was found that following an ERAS guideline reduced the incidence of PONV by 17% and reduced the average MME by 13.5 equivalents. Project implications include potential cost savings, reduced PACU length of stay, and improved patient outcomes.
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Title: Michigan potato research report. Vol. 53 (2021)
Date: 2022
Collection: Michigan Potato Research Reports

Title: I. Determination of Absolute Configuration of Chiral 1,2-Diols. II. Progress Towards the Total Synthesis of Napyradiomycin A1.
Creator: Torabi Kohlbouni, Saeedeh
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This dissertation focuses on two parts. The first part introduces an operationally simple and microscale method for the absolute stereochemical determination of 1,2-diols. In situ derivatization of 1,2-diols with dinaphthyl borinic acid generates the induced helicity of the two naphthyl groups, which leads to an observable ECCD spectrum. The observed P or M helicity follows a predictable trend for S and R chiral 1,2-diols, respectively.The Second chapter is the progress towards the asymmetric...
Show moreThis dissertation focuses on two parts. The first part introduces an operationally simple and microscale method for the absolute stereochemical determination of 1,2-diols. In situ derivatization of 1,2-diols with dinaphthyl borinic acid generates the induced helicity of the two naphthyl groups, which leads to an observable ECCD spectrum. The observed P or M helicity follows a predictable trend for S and R chiral 1,2-diols, respectively.The Second chapter is the progress towards the asymmetric catalytic synthesis of napyardiomycin A1. The chapter is divided to three sections. The first section is installation of chlorine chiral center at C3. This goal is achieved using cinchona chiral catalyst, and DCDMH as chloronium source. The second section is the synthesis of the -lapachone core of napyradiomycin A1, was accomplished using Diels-Alder/aromatization cascade reaction. The last section shows our effort toward the attachment of geranyl side chain.
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Title: DEVELOPING LIGNIN-BASED EPOXY AND POLYURETHANE RESINS
Creator: Nikafshar, Saeid
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Lignin, the most abundant natural aromatic polymer, is currently produced as by-product during biorefinery and chemical pulping processes. Lignin is rich in hydroxyl functional groups (both phenolic and aliphatic OH), making it an excellent raw material for synthesizing epoxy and polyurethane resins. However, there are several challenges in utilizing unmodified lignins as feedstock for product development, including high polydispersity/heterogeneity, low reactivity, poor accessibility of...
Show moreLignin, the most abundant natural aromatic polymer, is currently produced as by-product during biorefinery and chemical pulping processes. Lignin is rich in hydroxyl functional groups (both phenolic and aliphatic OH), making it an excellent raw material for synthesizing epoxy and polyurethane resins. However, there are several challenges in utilizing unmodified lignins as feedstock for product development, including high polydispersity/heterogeneity, low reactivity, poor accessibility of hydroxyl groups for reaction with co-monomers low solubility in common organic solvents, and dark color. There are significant variations in lignin characteristics, depending on the source of biomass and isolation methods. Therefore, in-depth lignin characterization is needed to provide the basic knowledge of the structural, chemical, and thermal properties to facilitate lignin valorization.This study was focused on lignin characterization and development of lignin-based epoxy and polyurethane resins. First, a wide range of lignin samples was fully characterized by measuring their ash contents, elemental analyses, hydroxyl contents, chemical structures, molar mass distributions, and thermal properties. Next, a novel method was developed to measure the reactivity of thirteen different unmodified lignins toward biobased epichlorohydrin (ECH). A partial least square regression (PLS-R) model (with 92 % fitting accuracy and 90 % prediction ability) was created to study the correlation between lignin properties and epoxy content. The results showed that lignins with higher phenolic hydroxyl contents and lower molecular weights were more suitable for replacing 100 % of toxic bisphenol A (BPA) in the formulation of resin precursors. Additionally, two epoxidized lignin samples (with the highest epoxy contents) were cured using a biobased hardener (Cardolite from cashew nutshell), showed comparable thermomechanical performances and thermal stabilities to a petroleum-based epoxy system. Biobased waterborne polyurethane resins (PUDs) were also developed by entirely replacing the petroleum-based polyol and the internal emulsifier with either alkaline pre-extraction lignins or enzymatic hydrolysis lignins as well as tartaric acid (a biobased diacid). The formulated resins had zero VOC (volatile organic compound), which was achieved by replacing toxic n-methyl-2-pyrrolidone (NMP) with cyrene (a biobased solvent). To further improve the mechanical properties of our biobased PUD resins, 20 wt.% of lignin was substituted with low hydroxyl value soy-polyol, which increased their tensile strength and elongation at break to 87% and 68% of a commercial PUD resin. The results of this study demonstrated that it is imperative to fully characterize lignin and choose the right lignin for each specific application. This approach enabled us to entirely replace petroleum-based raw materials (BPA and polyol) with lignin and formulate biobased epoxy and polyurethane resins.
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Title: Development and application of hierarchical models for monitoring avian soundscapes, populations, and communities
Creator: Doser, Jeffrey W.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Climate change, land use change, and other anthropogenic pressures are increasing species extinctions, phenology shifts, and drastic population declines. Avian populations and communities are particularly vulnerable to global change given their mobile and migratory life history strategies. Avian abundance has drastically declined throughout North America over several decades, which is compounded by phenological shifts in breeding periods and migratory patterns. Informed management and...
Show moreClimate change, land use change, and other anthropogenic pressures are increasing species extinctions, phenology shifts, and drastic population declines. Avian populations and communities are particularly vulnerable to global change given their mobile and migratory life history strategies. Avian abundance has drastically declined throughout North America over several decades, which is compounded by phenological shifts in breeding periods and migratory patterns. Informed management and conservation of avian populations and communities requires large-scale monitoring programs, as well as associated inferential tools to provide statistically robust inference using multiple data sources. In this dissertation, I develop a suite of hierarchical modeling approaches to understand avian soundscapes, populations, and communities. I leverage a hierarchical Bayesian modeling framework, which is ideally suited for complex wildlife data with numerous types of observation error and dependencies among data points. In Chapter 1, I provide a brief overview of avian monitoring approaches and their associated statistical analysis frameworks. In Chapters 2 and 3, I develop hierarchical models for the analysis of complex avian soundscape data, and apply these approaches to two case studies. In Chapter 2, I apply a two-stage hierarchical beta regression model to quantify the relationship between anthropogenic and biological sounds in avian soundscapes in western New York. In Chapter 3, I use a multivariate linear mixed model to assess disturbance impacts of a shelterwood logging on avian soundscapes in northern Michigan. In Chapter 4, I develop a multi-region, multi-species abundance model to quantify trends of avian species and communities using point count data across a network of National Parks in the northeastern US. In Chapters 5 and 6, I use a model-based data integration approach to yield improved inference on avian population and communities. In Chapter 5, I integrate automated acoustic recording data with point count data to estimate avian abundance, which I apply to a case study on the Eastern Wood Pewee (Contopus virens) in a National Historical Park in Vermont. In Chapter 6, I develop an integrated community occupancy model that combines multiple types of detection-nondetection data for inference on species-specific and community level occurrence dynamics, which I use to assess occurrence dynamics of a foliage-gleaning bird community in New Hampshire. These results exhibit the value of hierarchical models to partition ecological data into distinct observation and ecological components for improved inference on avian population and community dynamics. Future work should continue to leverage complex data sources within hierarchical modeling frameworks to address pressing conservation and management questions on avian populations, communities, and the ecosystem services they provide.
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Title: Molecular epidemiology, pangenomic diversity, and comparative genomics of Campylobacter jejuni
Creator: Rodrigues, Jose Alexandre
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Campylobacter jejuni, the leading cause of bacterial gastroenteritis in the United States, is often resistant to commonly used antibiotics and has been classified as a serious threat to public health. Through this work, we sought to evaluate infection trends, quantify resistance frequencies, identify epidemiological factors associated with infection, and use whole-genome sequencing (WGS) as well as comparative phylogenomic and pangenomic approaches to understand circulating C. jejuni...
Show moreCampylobacter jejuni, the leading cause of bacterial gastroenteritis in the United States, is often resistant to commonly used antibiotics and has been classified as a serious threat to public health. Through this work, we sought to evaluate infection trends, quantify resistance frequencies, identify epidemiological factors associated with infection, and use whole-genome sequencing (WGS) as well as comparative phylogenomic and pangenomic approaches to understand circulating C. jejuni populations in Michigan. C. jejuni isolates (n=214) were collected from patients via an active surveillance system at four metropolitan hospitals in Michigan between 2011 and 2014. Among the 214 C. jejuni isolates, 135 (63.1%) were resistant to at least one antibiotic. Resistance was observed for all nine antibiotics tested yielding 11 distinct resistance phenotypes. Tetracycline resistance predominated (n=120; 56.1%) followed by resistance to ciprofloxacin (n= 49; 22.9%), which increased from 15.6% in 2011 to 25.0% in 2014. Notably, patients with ciprofloxacin resistant infections were more likely to report traveling in the past month (Odds Ratio (OR): 3.0; 95% confidence interval (CI): 1.37, 6.68) and international travel (OR: 9.8; 95% CI: 3.69, 26.09). To further characterize these strains, we used WGS to examine the pangenome and investigate the genomic epidemiology of this set of C. jejuni strains recovered from Michigan patients. Among the 214 strains evaluated, 83 unique multilocus sequence types (STs) were identified that were classified as belonging to 19 previously defined clonal complexes (CCs). Core-gene phylogenetic reconstruction based on 615 genes identified three clades, with Clade I comprising six subclades (IA-IF) and predominating (83.2%) among the strains. Because specific cattle-associated STs, such as ST-982, predominated among strains from Michigan patients, we also examined a collection of 72 C. jejuni strains from cattle recovered during an overlapping time period by WGS. Several phylogenetic analyses demonstrated that most cattle strains clustered separately within the phylogeny, but a subset clustered together with human strains. Hence, we used high quality single nucleotide polymorphism (hqSNP) profiling to more comprehensively examine those cattle and human strains that clustered together to evaluate the likelihood of interspecies transmission. Notably, this method distinguished highly related strains and identified clusters comprising strains from both humans and cattle. For instance, 88 SNPs separated a cattle and human strain that were previously classified as ST-8, while the human and cattle derived ST-982 strains differed by >200 SNP differences. These findings demonstrate that highly similar strains were circulating among Michigan patients and cattle during the same time period and highlight the potential for interspecies transmission and diversification within each host. In all, the data presented illustrate that WGS and pangenomic analyses are important tools for enhancing our understanding of the distribution, dissemination, and evolution of specific pathogen populations. Combined with more traditional phenotypic and genotypic approaches, these tools can guide the development of public health prevention and mitigation strategies for C. jejuni and other foodborne pathogens.
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Title: STUDENTS’ TOOL USAGE, JUSTIFICATIONS, AND REPORTED CONFIDENCE WHEN USING DYNAMIC GEOMETRY ENVIRONMENTS
Creator: Wegner, Timothy Scott
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Dynamic Geometry Environments (DGEs) are popular tools in the exploration of geometry. This research is designed to explore the confidence of undergraduate mathematics students as they make mathematical statements when completing geometric tasks using DGEs. Students completed two series of tasks in both Euclidean and hyperbolic geometry. The first series of tasks asked students about properties of parallel transports and the second series of tasks asked students about the existence of regular...
Show moreDynamic Geometry Environments (DGEs) are popular tools in the exploration of geometry. This research is designed to explore the confidence of undergraduate mathematics students as they make mathematical statements when completing geometric tasks using DGEs. Students completed two series of tasks in both Euclidean and hyperbolic geometry. The first series of tasks asked students about properties of parallel transports and the second series of tasks asked students about the existence of regular polygons. The ten students in this research used Geometry Explorer, a DGE which they had previous experience using in Euclidean geometry, but minimal experience using in hyperbolic geometry. Hyperbolic geometry tasks were included in this study because features of that geometry (e.g. curved lines and unexpected length measure) were expected to pose challenges for students’ intuitive expectations. Because of this lack of intuition, students may use the features of DGEs (e.g. dragging and measurement) to make various justifications (e.g. authoritative, inductive, and deductive) of the mathematical claims they are making. Both the features of the DGE and students’ justifications affect their confidence in the claims they make. This research explored the interaction between these three factors. Analysis of the data showed that these two series of tasks elicited both dragging and measurement tool usage. During the parallel transport tasks, students used these tools in both in an exploratory mode looking for relationships and a validation mode confirming previous conjectures. During the regular polygon construction tasks, students mainly used the tools in a validation mode. Additionally, many students waited until the hyperbolic portion of the tasks to begin using these tools. The tasks elicited a range of justifications, though students generally used inductive arguments. Deductive justifications, when used, were mainly for familiar tasks that took place within Euclidean geometry. Reported confidence was high across both series of tasks as well as across both Euclidean and hyperbolic geometry when working with the DGE. Reported confidence dropped when working on conjecturing or proof validation prompts that did not use the DGE.This research suggests there is still much work to be done investigating how students use tools, make justifications, and report confidence when using DGEs in both Euclidean and non-Euclidean geometries. The researcher recommends further study including the exploration of additional tools within DGEs, the dynamics of working in partners within DGEs, and how students’ expectations of justification affect their responses.
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Title: DEVELOPMENT OF 3D BIOACTIVE AND ANTIBACTERIAL SILICATE-BASED SCAFFOLDS FOR BONE TISSUE REGENERATION IN LOAD-BEARING APPLICATIONS
Creator: Marsh, Adam Christoph
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Current gold-standard approaches to addressing the needs of bone defects in load-bearing applications entail the use of either autographs or allographs. Both solutions, however, are imperfect as both autographs and allographs carry the risk of additional trauma, threat of disease transmission, and potential donor rejection respectively. Porous 3D scaffolds are attractive alternatives, illuminating a potential path towards achieving the ideal scaffold for targeting bone tissue regeneration in...
Show moreCurrent gold-standard approaches to addressing the needs of bone defects in load-bearing applications entail the use of either autographs or allographs. Both solutions, however, are imperfect as both autographs and allographs carry the risk of additional trauma, threat of disease transmission, and potential donor rejection respectively. Porous 3D scaffolds are attractive alternatives, illuminating a potential path towards achieving the ideal scaffold for targeting bone tissue regeneration in load-bearing applications, usurping autographs to become the new gold-standard. To unlock the full healing potential of 3D scaffolds, such scaffolds must be multifunctional such that (1) their mechanical performance meets the requisite requirements as dictated by the mechanical performance characteristics of interest for native bone tissue, (2) they stimulate the necessary biological responses for bone tissue regeneration, and (3) they exhibit antibacterial characteristics to combat the threat of infection. To date, no reports document 3D scaffolds exhibiting all three performance characteristics. The aim of this dissertation, therefore, is to deliver 3D scaffolds that are mechanically competent, possess and exhibit inherent and advanced antibacterial characteristics, and are successful at providing the needed biological characteristics for bone tissue regeneration. To achieve this, this dissertation implements a multidisciplinary approach, utilizing comprehensive structural characterization across a wide range of scales to elucidate process – performance relationships to execute scientifically driven modifications to engineer and deliver a 3D scaffold to successfully target bone tissue regeneration in load-bearing applications. A silver-doped bioactive glass-ceramic (Ag-BG) composition was selected as the material for scaffold synthesis due to its inherent and attractive antibacterial and biological performance characteristics. Two fundamentally different processing approaches were utilized for synthesizing Ag-BG scaffolds: the polymer foam replication technique and fused filament fabrication (FFF). The Ag-BG scaffolds studied herein were found to exhibit advanced antibacterial performance characteristics against methicillin-resistant Staphylococcus aureus (MRSA), a common pathogen implicated in osteomyelitis development, able to combat MRSA both in planktonic and biofilm forms. Ag-BG scaffolds demonstrated the ability to form an apatite-like layer when immersed in simulated body fluid (SBF), an indicator that Ag-BG scaffolds will induce the necessary mineralization for bone tissue regeneration, in addition to exhibiting attractive cell viability, proliferation, and differentiation characteristics when studied in vitro. The mechanical performance of Ag-BG scaffolds reported herein saw progressive improvements in each iteration of Ag-BG scaffold synthesis, achieving desirable mechanical competency and reliability as a result of the multidisciplinary approach formulated. In addition to the exploration of developing 3D antibacterial and biological silicate-based scaffolds capable of targeting bone tissue regeneration in load-bearing applications, foundational work towards the development of class II hybrid scaffolds comprised of gelatin methacryloyl (GelMA) and Ag-BG for targeting softer tissue regeneration. The novel syntheses applied to the successful molecular coupling of GelMA and Ag-BG presents an attractive class II hydrogel showing great promise as a compatible ink for 3D bioprinting cell-laden scaffolds capable of targeting tissue regeneration of more sophisticated systems.
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Title: IMPROVING YIELD AND QUALITY OF LEAFY GREENS GROWN INDOORS WITH PRECISE RADIATION, TEMPERATURE, AND CARBON DIOXIDE MANAGEMENT
Creator: Tarr, Sean T.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Indoor agriculture systems can allow for precise manipulation of the mean daily temperature (MDT), carbon dioxide (CO2) concentration, and photosynthetic photon flux densities (PPFD). Identifying how these environmental parameters interact to influence crop growth, development, yield, and color can assist growers with selecting their desired growing environment. Therefore, the objectives of Expt. 1 and 2 were to quantify and model how PPFD and CO2 concentrations interact with MDT to influence...
Show moreIndoor agriculture systems can allow for precise manipulation of the mean daily temperature (MDT), carbon dioxide (CO2) concentration, and photosynthetic photon flux densities (PPFD). Identifying how these environmental parameters interact to influence crop growth, development, yield, and color can assist growers with selecting their desired growing environment. Therefore, the objectives of Expt. 1 and 2 were to quantify and model how PPFD and CO2 concentrations interact with MDT to influence the growth, yield, and quality of hydroponically grown green butterhead ‘Rex’ and red oakleaf lettuce ‘Rouxaï RZ’. In Expt. 3 we developed models to predict growth parameters and cardinal temperatures of lettuce, arugula, and kale from 8 to 33 °C. In Expt. 1, lettuce ‘Rex’ and ‘Rouxaï RZ’ were grown in deep-flow hydroponic tanks under a PPFD of 150 or 300 μmol·m‒2·s‒1 for 17 h·d–1 at MDTs of 20, 23, or 26 °C. PPFD and MDT interacted to influence biomass accumulation of both cultivars. In Expt. 2, lettuce ‘Rex’ and ‘Rouxaï RZ’ were grown under a PPFD of 300 μmol·m‒2·s‒1 and at the same MDTs as Expt. 1, but with CO2 concentrations of 500, 800, or 1200 μmol·mol–1. Dry mass of both cultivars was influenced by the interaction of CO2 and MDT; biomass accumulation was greatest at 800 μmol·mol–1 CO2 at MDTs of 23 and 26 °C. In Expt. 3, ‘Rex’ and ‘Rouxaï RZ’, kale ‘Red Russian’, and arugula ‘Astro’ were grown at MDTs of 8, 13, 18, 23, 28, or 33 °C. ‘Rex’ and ‘Rouxaï RZ’ had similar base and optimal temperature estimates of 8 °C and 26 °C, while arugula and kale were lower at 6 °C and 23 °C.
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Title: TECHNOLOGICAL INNOVATION’S IMPACT ON AUDIT QUALITY AND AUDIT FEES : EVIDENCE FROM DISTANT AUDITS
Creator: Fritz, Aaron
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This paper examines the impact of advances in communication technology on audit quality and audit fees over the first two decades of the twenty-first century. Using theories on virtual teams from the management literature and distant audits as a setting where auditors and clients are most reliant on communication technology, I hypothesize that advances in communication technology improve audit quality over time for distant audits, specifically, and when compared to local audits. With two...
Show moreThis paper examines the impact of advances in communication technology on audit quality and audit fees over the first two decades of the twenty-first century. Using theories on virtual teams from the management literature and distant audits as a setting where auditors and clients are most reliant on communication technology, I hypothesize that advances in communication technology improve audit quality over time for distant audits, specifically, and when compared to local audits. With two measures of audit quality (discretionary accruals and misstatements) and an analysis that identifies three “eras” of communication technology in the 2000s, I find evidence that audit quality has seen statistically significant improvement over time with advances in communication technology for distant audits and that this improvement is statistically significant when compared to local audits as a control group. In an additional test, I find evidence that advances in communication technology also impact audit fees. Specifically, audit fees of distant audits increase over time at a lower rate than local audits suggesting that distant audits benefit more from advances in communication technology. These results are important because they provide evidence that communication technology has benefited audits by increasing quality and reducing fees, particularly for distant audit clients. This is relevant to the current audit environment where firms are considering long-term remote working strategies that will be heavily reliant on these technologies.
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Title: ADVANCING BLUEBERRY POSTHARVEST BIOLOGY : THE EFFECT OF SULFUR DIOXIDE FUMIGATION ON BLUEBERRY PHYSIOLOGY AND RNA-SEQ OF THE BLUEBERRY-COLLETOTRICHUM FIORINIAE PATHOSYSTEM IN ‘ELLIOTT’ FRUIT
Creator: Abeli, Patrick
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The physiology and biology of blueberry fruit is the most important consideration for understanding postharvest storage. Fruit physiology is responsive to many stimuli including biotic, genetic, and environmental inputs. The extent to which a blueberry fruit are affected by these factors is largely cultivar dependent. The following studies address two aspects of blueberry fruit postharvest biology as it relates to pest control: In Chapter 2, we explore the effect of SO2 fumigation on five...
Show moreThe physiology and biology of blueberry fruit is the most important consideration for understanding postharvest storage. Fruit physiology is responsive to many stimuli including biotic, genetic, and environmental inputs. The extent to which a blueberry fruit are affected by these factors is largely cultivar dependent. The following studies address two aspects of blueberry fruit postharvest biology as it relates to pest control: In Chapter 2, we explore the effect of SO2 fumigation on five blueberry cultivars: ‘Bluecrop’, ‘Draper’, ‘Elliott’, ‘Jersey’, and ‘Liberty’ and the extent to which SO2 fumigation can be used to disinfest blueberry fruit of blueberry maggot (BBM) Rhagoletis mendax Curran. In Chapter 3, we use RNA sequencing (RNA-seq) to reveal genes differentially expressed (DE) in ‘Elliott’ fruit in response to infection by Colletotrichum fioriniae compared to mock- (water-) inoculated fruit. By filtering out DE genes in mock-inoculated fruit postharvest, as well as DE genes in infected ‘Jersey’ and ‘Draper’ fruit, we discovered 113 genes unique to ‘Elliott’ fruit that are inoculation-responsive. This set of genes include canonical plant resistance genes as well as genes associated with secondary metabolite biosynthesis, cell wall metabolism, reactive oxygen species production and scavenging, and the hypersensitive response. These studies provide important groundwork for future blueberry breeding by identifying cultivars with genetics and physiology amenable to different interventions for reducing postharvest fruit losses.
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Title: Regulation of Chlamydomonas reinhardtii cell cycle during synchronous growth
Creator: Lin, Yang-Tsung
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The regulation of the cell cycle in microalgae has long been a central topic in third-generation biofuel studies, as it relates to biomass accumulation and lipid production, the two determining factors of economically feasible biofuel production. The discovery of Compromised Hydrolysis of TAG 7 (CHT7) in the green alga Chlamydomonas reinhardtii has provided valuable insights into the metabolic status-dependent regulation of the cell cycle. CHT7 belongs to the CHC protein family, members of...
Show moreThe regulation of the cell cycle in microalgae has long been a central topic in third-generation biofuel studies, as it relates to biomass accumulation and lipid production, the two determining factors of economically feasible biofuel production. The discovery of Compromised Hydrolysis of TAG 7 (CHT7) in the green alga Chlamydomonas reinhardtii has provided valuable insights into the metabolic status-dependent regulation of the cell cycle. CHT7 belongs to the CHC protein family, members of which include transcriptional regulators programming the initiation of cell division. A similar role of CHT7 in mediating cell cycle progression has been suggested. However, the regulatory mechanism and specific processes regulated by CHT7 have yet to be determined. In this dissertation, I applied bioinformatics approaches to comprehensively study CHT7-mediated gene regulation during the cell cycle using cell cultures synchronously grown in bioreactors. I found that specific pathways such as DNA replication, chromosome condensation, and spindle assembly are affected by the absence of CHT7. Other affected pathways include cell-wall remodeling and previously uncharacterized putative kinase cascades. In addition, I discovered the presence of two potential cis-regulatory elements near the transcription start site of misregulated genes in cht7, which are potentially linked to homeodomain transcription factors. Moreover, I explored the potential relationship between the CHT7-mediated pathway and the gene network governed by the retinoblastoma protein complex. Lastly, I characterized the function of a novel CHC protein in cell cycle progression and compared it with the role of CHT7. Together, these studies facilitate a better understanding of the cell cycle regulation in microalgae.
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Title: BLENDING OF POLY(LACTIC ACID) AND POLY(3-HYDROXYBUTYRATE-CO-3-HYDROXYVALERATE) – THE EFFECT OF MALEATED PLA AS A REACTIVE COMPATIBILIZER AND BIODEGRADATION STUDY
Creator: Muangmala, Woranit
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Poly(lactic acid), PLA was blended with poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV, based on a crossed mixture-factorial experimental design with three levels of factorial variable of the type of pre-produced maleated PLA, PLAgMA-type, used as the blend compatibilizer, and three components mixture variable which were the contents of PLA, PHBV, and PLAgMA, included in the polymer blends. The mixture model was based on the constrained level of the weight fraction of each mixture...
Show morePoly(lactic acid), PLA was blended with poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV, based on a crossed mixture-factorial experimental design with three levels of factorial variable of the type of pre-produced maleated PLA, PLAgMA-type, used as the blend compatibilizer, and three components mixture variable which were the contents of PLA, PHBV, and PLAgMA, included in the polymer blends. The mixture model was based on the constrained level of the weight fraction of each mixture component as follows: 0.2 ≤ PHBV ≤ 0.7, 0.2 ≤ PLA ≤ 0.7, and 0.05 ≤ PLAgMA ≤ 0.15. The design of experiment yielded 16 runs of compatibilized blends, with 2 runs of non-compatibilized blend and 2 runs of neat polymers, PLA and PHBV, for comparison. The model of relationship between variables was derived based on the multiplication of a linear relationship of one factorial variable with a quadratic Scheffe model of the mixture ingredients. Multiple formulas of the blend compatibilizer, maleated PLA (PLA-g-MA), were pre-produced by a reactive melt blending method to functionalize maleic anhydride, MA, on the PLA backbone in a twin-screw co-rotating extruder. Dicumyl peroxide, DCP, was used as a free radical initiator in the reactive blending. The formulas were designed using response surface experimental design to determine the effect of the contents of MA and DCP on the amount of grafted MA, MA-grafting yield, and the molecular weight properties, Mn, Mw, IV, and dispersity of PLA-g-MA. The model regression indicated a significant effect of DCP with increasing DCP tending to reduce the MA-grafting yield, Mn, Mw, and IV, and increase the dispersity. The optimum point that maximized the desirability of these responses simultaneously was with the content of DCP = 0.1 wt. % and MA = 3.94 wt. % (PLA basis). Blending of PLA and PHBV clearly increased the crystalline fraction of the blends compared to neat PLA, which affects the barrier properties of the materials. Inclusion of PHBV at 25 wt. % in the non-compatiblilized blend and at 45 – 60 wt. % in compatibilized blends resulted in more than 60% reduction of water and O2 permeability compared to PLA. The compatibilized PLA/PHBV blend with PLA weight fraction of 0.45 achieved 300% increase in the tensile strength compared to the neat PHBV; this level of improvement was equivalent to the non-compatibilized blend containing PLA 75 wt. %. This was attributed to enhanced interfacial adhesion that was evidently supported by increased miscibility between the blend components in compatibilized blends which was exhibited through the shifting of Tg of PLA and the decrease of k constants based on the Gordon-Taylor equation of the compatibilized blends. The factorial-mixture model regression suggested the validity of the mixture variable of PLA, and PHBV in both tensile and barrier properties; the PLAgMA had a significant effect only on the tensile performance of the polymer blends. The overlapped contour plots as well as the desirability functions could be used to optimize the mixture of the PLA/PHBV blend components that provide desirable tensile and barrier properties. A biodegradation study was conducted on neat PLA, PHBV, non-compatibilized blend of 75:25 PLA/PHBV, and compatibilized blend of 65:15:20 PLA/PLA-g-MA/PHBV. PLA/PLA-g-MA/PHBV was the fastest to reach 100% mineralization, followed by PLA and PLA/PHBV samples, according to the CO2 evolution and % mineralization, whereas PHBV reached only 81% mineralization at the end of the test of 180 days. The facilitation of anhydride present in PLA-g-MA on the hydrolysis of PLA was a major cause of the fast biodegradation of PLA/PLA-g-MA/PHBV. A sharp increase in enthalpy of fusion, ΔHf, as well as a rapid reduction of the molecular weight of PLA/PLA-g-MA/PHBV compared to PLA and PLA/PHBV support the occurrence of an elevated rate of hydrolysis. The PHBV sample showed the biodegradation was barely affected by abiotic hydrolytic degradation as the thermal properties did not show any shifting of the melting transition and the ΔHf remained stable until 30 days of the test; the main mechanism was the enzymatic microbial degradation causing an erosion at the surface rather than affecting the bulk properties such as the molecular weight. The scanning electron micrographs also revealed the biodegradation of PHBV that initially occurred was from the surface and later showed the degradation of the crystalline structure. The PLA crystals formed during the biodegradation of PLA/PHBV and PLA/PLA-g-MA/PHBV samples could be seen from SEM photos.
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Title: DESIGNING OUR FREEDOM : A NARRATIVE INQUIRY AND VISUAL RHETORICAL ANALYSIS OF BLACK WOMEN ENTREPRENEURS DIGITAL CONTENT STRATEGY ON SOCIAL NETWORKING SITES
Creator: Wourman, Ja'La Janice
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This study explores the role of race and identity in Black women entrepreneurship and how each of these play a part when developing content for online audiences. The purpose of this study was to better understand how our intersecting identities are important to draw upon or consider, when conducting research in work-place studies or entrepreneurship for technical and professional communication scholars. And with the rise of digital platforms, I wanted to better understand if the...
Show moreThis study explores the role of race and identity in Black women entrepreneurship and how each of these play a part when developing content for online audiences. The purpose of this study was to better understand how our intersecting identities are important to draw upon or consider, when conducting research in work-place studies or entrepreneurship for technical and professional communication scholars. And with the rise of digital platforms, I wanted to better understand if the entrepreneurial journey factors into the design process of developing content for online audiences. To answer these questions, I used a narrative inquiry approach to conduct 5 separate interviews for each of my participants. The purpose of the interviews was to amplify the voices of each of my participants drawing from Patricia Hill Collins and the Combahee River Collective’s Black feminist theory. I then conducted a content analysis of 3 images from each of my participants business Instagram profiles, to demonstrate how design and cultural background can play a role in developing content. The results from this study revealed 3 major outcomes from each of the interviews and 4 emerging themes in the images used for all 5 participants content analysis of Instagram. Together, the themes and outcomes show a direct correction of race, culture, and design in content strategy. Using this data, I was able to develop tenets to help scholars and practitioners imagine a culturally centered design framework for developing content for diverse audiences and situations.
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Title: Robust Maxwell Solvers for Large Scale Particle-in-Cell Simulations
Creator: Crawford, Zane Daniel
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The design of modern devices is impacted heavily by the use and availability of robust, accurate, and efficient computational tools. This includes modeling devices that exploit plasma physics like particle accelerators, klystrons, ion thrusters, and micro-plasma generators among many other applications. While there are a number of current and emerging applications, the common thread between all is the need to accurately and efficiently capture all the relevant physics in geometrically...
Show moreThe design of modern devices is impacted heavily by the use and availability of robust, accurate, and efficient computational tools. This includes modeling devices that exploit plasma physics like particle accelerators, klystrons, ion thrusters, and micro-plasma generators among many other applications. While there are a number of current and emerging applications, the common thread between all is the need to accurately and efficiently capture all the relevant physics in geometrically intricate structures. The holy grail is to enable topology optimization to explore the design space. But all this requires rigorous translation from the continuous to the discrete world, while capturing all the underlying physics and not adding spurious artifacts due to discretization.A common computational model to perform this analysis is the particle-in-cell (PIC) method. It provides a straightforward paradigm to self-consistently solve for the distribution of the plasma as a collection of particles. The prevailing approach to solve for the fields in PIC is the finite difference time domain method (FDTD), or EM-FDTDPIC. But this effort leaves much to be desired, given the leaps that have been made in the finite element method; indeed, the latter is the method of choice for most commercial tools that that have become the de-facto workhorse in RF design industry. As a result, in the past decade, considerable effort has been expended in developing finite element (FEM) based PIC schemes, EM-FEMPIC. But we are still not there. One major concern of utilizing EM-FEMPIC over EM-FDTDPIC is the computational cost of FEM, which is greater than FDTD, despite the advantages of field and geometry accuracy FEM affords.This dissertation seeks to develop (i) a theoretically rigorous means to translate from the continuous to the discrete world while ensuring that there are no spurious artifacts, (ii) develops a higher order accurate method in both space and time, and (iii) overcomes cost complexity by introducing a linear scaling domain decomposition scheme. In all of these, the methods developed ensure that the necessary conservation properties are satisfied to machine precision. Numerous examples developed demonstrate these claims.
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Title: TRANSPARENT, BIAXIALLY ORIENTED BARRIER FILMS FROM POLYPROPYLENE-CLAY NANOCOMPOSITES
Creator: Lu, Xing
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The research work is divided into three sections – (i) transparent barrier films, (ii) high expansion foams and (iii) transparent molded panels, all from polypropylene clay nanocomposites. Biaxially oriented polypropylene (BOPP) is used for transparent, flexible high-barrier packaging film. The biaxial orientation process improves the barrier to gases and the mechanical properties by rearrangement of the crystal structure. Polymer nanocomposites incorporating layered nanofiller have the...
Show moreThe research work is divided into three sections – (i) transparent barrier films, (ii) high expansion foams and (iii) transparent molded panels, all from polypropylene clay nanocomposites. Biaxially oriented polypropylene (BOPP) is used for transparent, flexible high-barrier packaging film. The biaxial orientation process improves the barrier to gases and the mechanical properties by rearrangement of the crystal structure. Polymer nanocomposites incorporating layered nanofiller have the potential to provide striking enhancements in barrier to water vapor and oxygen. However, there is a conflict between addition of nanoclay and stretchability in the BOPP process where rapid deformation and high stress are experienced. In this work, we demonstrated successful achievement of both stretchability and property improvements after incorporating an innovative masterbatch additive based on nanoclay into polypropylene. The maximum area stretch ratio of 7 × 7 achieved without film breakage during biaxial stretching of nanocomposite was as high as that obtained with the unfilled or neat polypropylene. Transmission electron micrographs and dynamic shear rheology revealed that the extent of dispersion of nanoclay in polypropylene was improved after the biaxial stretching. Small angle X-Ray scattering revealed that the crystalline lamellar thickness in the BOPP-NC was larger than in BOPP. Furthermore, the crystalline orientation was more evenly distributed in the plane of the BOPP-NC film as seen from 2D-SAXS images while the degree of crystallinity was seen to be very similar in BOPP and BOPP-NC from wide angle X-Ray diffraction (WAXD). As a result, BOPP nanocomposite film with significantly enhanced stiffness and barrier to both water vapor and oxygen was achieved without sacrificing transparency. In addition, the simultaneous and sequential biaxial stretching behavior of these nanocomposite under processing conditions relevant to industry practice were compared. It was found the characteristic deformation behavior differs significantly between two stretching modes. 2D SAXS revealed the morphology difference in terms of lamellar orientation where a more isotropic in-plane orientation was found in simultaneously stretched films and a preferential alignment along the two stretching directions especially TD was found in sequentially stretched films.In the second section, polypropylene nanocomposites were evaluated with batch foaming using supercritical CO2 in a pressure vessel. An ultra-high expansion ratio of 35.8 was achieved which can be ascribed to two factors: 1) The high melt strength and strain hardening behavior by addition of nanoclay helps the nanocomposite foam cell withstand the high expansion force allowing for a relatively larger cell size capability. 2) The nanoclay also increased the cell density significantly. It is found that biaxial expansion induced orientation and improved delamination of nanoclay. Consequently, the nanocomposite foam exhibited a well-defined cell structure compared to foamed PP. Finally, incorporation of the same nanolayers with selected proportions of compatibilizer in thermoplastic olefin blends or blends of polypropylene homopolymer with toughening copolymers of ethylene and propylene yielded significant improvements in the transmission of light and reduction of haze through molded panels of the multiphase composite compared to molded panels from the unfilled blends.
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Title: Towards Accurate Ranging and Versatile Authentication for Smart Mobile Devices
Creator: Li, Lingkun
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Internet of Things (IoTs) was rapidly developed during past years. Smart devices, such as smartphones, smartwatches, and smart assistants, which are equipped with smart chips as well as sensors, provide users with many easy used functions and lead them to a more convenient life. In this dissertation, we carefully studied the birefringence of the transparent tape, the nonlinear effects of the microphone, and the phase characteristic of the reflected ultrasound, and make use of such effects to...
Show moreInternet of Things (IoTs) was rapidly developed during past years. Smart devices, such as smartphones, smartwatches, and smart assistants, which are equipped with smart chips as well as sensors, provide users with many easy used functions and lead them to a more convenient life. In this dissertation, we carefully studied the birefringence of the transparent tape, the nonlinear effects of the microphone, and the phase characteristic of the reflected ultrasound, and make use of such effects to design three systems, RainbowLight, Patronus, and BreathPass, to provide users with accurate localization, privacy protection, and authentication, respectively.RainbowLight leverages observation direction-varied spectrum generated by a polarized light passing through a birefringence material, i.e., transparent tape, to provide localization service. We characterize the relationship between observe direction, light interference and the special spectrum, and using it to calculate the direction to a chip after taking a photo containing the chip. With multiple chips, RainbowLight designs a direction intersection based method to derive the location. In this dissertation, we build the theoretical basis of using polarized light and birefringence phenomenon to perform localization. Based on the theoretical model, we design and implement the RainbowLight on the mobile device, and evaluate the performance of the system. The evaluation results show that RainbowLight achieves 1.68 cm of the median error in the X-axis, 2 cm of the median error in the Y-axis, 5.74 cm of the median error in Z-axis, and 7.04 cm of the median error with the whole dimension.It is the first system that could only use the reflected lights in the space to perform visible light positioning. Patronus prevents unauthorized speech recording by leveraging the nonlinear effects of commercial off-the-shelf microphones. The inaudible ultrasound scramble interferes recording of unauthorized devices and can be canceled on authorized devices through an adaptive filter. In this dissertation, we carefully studied the nonlinear effects of ultrasound on commercial microphones. Based on the study, we proposed an optimized configuration to generate the scramble. It would provide privacy protection againist unauthorized recordings that does not disturb normal conversations. We designed, implemented a system including hardware and software components. Experiments results show that only 19.7% of words protected by Patronus' scramble can be recognized by unauthorized devices. Furthermore, authorized recordings have 1.6x higher perceptual evaluation of speech quality (PESQ) score and, on average, 50% lower speech recognition error rates than unauthorized recordings. BreathPass uses speakers to emit ultrasound signals. The signals are reflected off the chest wall and abdomen and then back to the microphone, which records the reflected signals. The system then extracts the fingerprints from the breathing pattern, and use these fingerprints to perform authentication. In this dissertation, we characterized the challenge of conducting authentication with the breathing pattern. After addressing these challenges, we designed such a system and implemented a proof-of-concept application on Android platform.We also conducted comprehensive experiments to evaluate the performance under different scenarios. BreathPass achieves an overall accuracy of 83%, a true positive rate of 73%, and a false positive rate of 5%, according to performance evaluation results. In general, this dissertation provides an enhanced ranging and versatile authentication systems of Internet of Things.
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Title: THE EPIGENETIC MECHANISMS OF POLYCOMB AND TRITHORAX PROTEINS IN STEM CELL MAINTENANCE AND LEUKEMOGENESIS
Creator: Aljazi, Mohammad
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Functionally, Polycomb repressive complex 2 (PRC2) mediates transcriptional repression of differentiation genes critical for mouse embryonic stem cell (mESC) maintenance. Culturing mESCs in 2i serum-free medium inhibits FGF/ERK signaling and activates the Wnt/β-catenin pathway, which induces a naive cell state characterized by a reduced expression of lineage-specific genes. Interestingly, in naive mESCs, both PRC2 chromatin occupancy and the repressive histone3 lysine 27 trimethylation ...
Show moreFunctionally, Polycomb repressive complex 2 (PRC2) mediates transcriptional repression of differentiation genes critical for mouse embryonic stem cell (mESC) maintenance. Culturing mESCs in 2i serum-free medium inhibits FGF/ERK signaling and activates the Wnt/β-catenin pathway, which induces a naive cell state characterized by a reduced expression of lineage-specific genes. Interestingly, in naive mESCs, both PRC2 chromatin occupancy and the repressive histone3 lysine 27 trimethylation (H3K27me3) modification they mediate are largely depleted. To explore the molecular mechanism attributing to the transcriptional changes in naive cells, we performed RNA-sequencing for mESCs cultured in serum versus 2i medium. Gene expression analysis revealed reduced Jarid2 levels in naive mESCs. Reactivation of FGF/ERK signaling caused elevated Jarid2 expression, whereas ERK1/2 deletion decreased its expression levels. Ectopic expression of ERK depleted cells restored Jarid2 expression, showing that Jarid2 expression dependent on ERK signaling. Using ChIP-seq analysis, we observed reduced occupancy for Jarid2 and PRC2 and decreased H3K27me3 levels in both naive and Erk1/2 depleted mESCs. Expression of Jarid2 in Erk1/2 depleted cells reestablished PRC2 occupancy and H3K27me3 modifications. Taken together, these results reveal the molecular mechanism associated with FGF/ERK signaling and PRC2 recruitment in mESCs.The TrxG (Trithorax) group member ASH1L serves as a regulator of cell development. However, its functional role in MLL-rearranged leukemia initiation and maintenance is not well understood. Using an Ash1L conditional knockout mouse model, we demonstrated that ASH1L in hematopoietic progenitor cells (HPCs) impaired initiation of MLL-AF9-induced leukemic transformation in vitro. Ablation of ASH1L in the MLL-AF9-transformed leukemia cells impeded maintenance in vitro and leukemia progression in vivo. Furthermore, Ash1L depleted cells expressing wild-type ASH1L rescued MLL-AF9-induced leukemia transformation, while the transformation of cells expressing enzymatically inactive ASH1L inhibited their maintenance. Implementation of RNA-sequencing analysis revealed that ASH1L controls the expression of MLL-AF9 target genes by occupying their promoters and depositing H3K36me2 marks at these sites. Altogether, these results demonstrate that the enzymatic activity of ASH1L is crucial for MLL-AF9-induced leukemic transformation and maintenance. In addition, our study identifies a potential therapeutic target in MLL-AF9-induced leukemias. Histone post-translational modifications are vital for epigenetic mediated gene regulation. While past studies have characterized the functional role of many histone H3 lysine residues modifications, the post-translational modification of histone H3 lysine 37 and the factors contributing to these modifications remain undefined in mammals. Using in vitro methyltransferase assays, we found that SMYD family member 5 (SMYD5) catalyzes mono-methylation of H3 lysine 36 and 37 (H3K36/K37me1). Mutation of the conserved histidine within the catalytic SET domain abolished SMYD5 methyltransferase activity in vitro. Additionally, loss of Smyd5 in mESCs reduces the global histone H3K37me1 level in cells. Thus, our data functionally identifies SMYD5 as an H3 specific methyltransferase that mediates H3K36me/H3K37me1 in vitro. It also reveals that SMYD5 serves as one of the histone methyltransferases catalyzing histone H3K37me1 in vivo.
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