Digital Commons Network^™

Multi-Scale Modeling Of High-Shear Granulation, Daniel A. Pohlman

Open Access Dissertations

High shear wet granulation is a particle design process used to increase the size of a primary powder material through the addition of liquid binder. This thesis focuses on the multi-scale nature of high-shear granulation in order to understand behavior changes due to coupled consolidation and coalescence as well as operational changes that occur during the scale up of horizontal ploughshare mixer granulators. The methodology relied on a micro-scale model for coalescence, a meso-scale model to describe flow within the granulator and a macro-scale population balance to describe the whole system.

The Experience Of Men After Miscarriage, Stephanie Dianne Rose

Open Access Dissertations

Miscarriage is a relatively common event that occurs in approximately 15 to 20 percent of identified pregnancies (Maker & Ogden, 2003). Men and women often view miscarriage as a real and meaningful loss (Johnson & Puddifoot, 1996; McCreight, 2004). The vast majority of research focused on the experience of miscarriage has emphasized the feelings, thoughts, and behaviors of women (Conway & Russell, 2000; McCreight, 2004). However, minimal research exists focused on men’s experience after miscarriage (Rinehart & Kiselica, 2010). The present phenomenological study examined the experience of men after miscarriage including aspects such as responses (e.g., emotions and behaviors), coping, …

Dietary And Exercise Effects On Neural Responses To Visual Food Stimuli In Overweight And Obese Adults, Richard Sayer

Open Access Dissertations

Results from human neuroimaging studies consistently demonstrate that obesity is associated with altered neural reward processing of food-relevant cues. These observations have caused some investigators to question whether behavioral interventions such as dietary manipulations or physical activity might modulate processing of food cues in reward-related brain regions. The use of functional magnetic resonance imaging (fMRI) to measure neural responses to visual food stimuli is a commonly utilized paradigm for assessing neural reward responses relating to ingestive behavior of foods in humans. Using this study design, limited evidence suggests that increases in dietary protein and participation in acute and chronic aerobic …

Scaffolding Early Engineers' Design Learning With A Videogame: Investigating The Influence Of Minecraft As A Platform For Design Ideation, Corey Schimpf

Open Access Dissertations

In this manuscript a modified commercial game, Minecraft, was used to assist early engineering students' learning the design process. More specifically, a designed-based research approach was employed utilizing a concurrent mixed methods to investigate the use of Minecraft for learning about the concept generation stage of design. Survey instruments measuring understanding of the design process, in-depth interviews on students’ interactions with the platform and iterations of students’ virtual artifacts were captured for analysis. Although no learning gains were detected from pre to post instrument, several analytical methods including visual content analysis of students’ artifacts, discourse analysis of students’ framing of …

Scaling Up Network Analysis And Mining: Statistical Sampling, Estimation, And Pattern Discovery, Nesreen Kamel Ahmed

Open Access Dissertations

Network analysis and graph mining play a prominent role in providing insights and studying phenomena across various domains, including social, behavioral, biological, transportation, communication, and financial domains. Across all these domains, networks arise as a natural and rich representation for data. Studying these real-world networks is crucial for solving numerous problems that lead to high-impact applications. For example, identifying the behavior and interests of users in online social networks (e.g., viral marketing), monitoring and detecting virus outbreaks in human contact networks, predicting protein functions in biological networks, and detecting anomalous behavior in computer networks. A key characteristic of these networks …

A Comparison Of First-Semester Organic Chemistry Students’ Experiences And Mastery Of Curved-Arrow Formalism In Face-To-Face And Cyber Peer-Led Team Learning, Sarah Beth Wilson

Open Access Dissertations

The cyber Peer-Led Team Learning (cPLTL) workshops are a synchronous online adaptation of the educational intervention PLTL, in which students, under the guidance of undergraduate peer facilitators, collaboratively solve problems in small groups. The purpose of this parallel convergent mixed methods study was to assess the impact of implementing cPLTL in an organic chemistry course on students’ workshop experiences, performance, and development of curved arrow formalism skills. Statistical analyses revealed comparable attendance rates, distribution of course grades, and achievement on American Chemical Society First-semester Organic Chemistry Exams. However, plotting workshop grades by AB, C, and DFW grade groupings revealed that …

Probing Cellular Mechano-Sensitivity Using Biomembrane-Mimicking Cell Substrates Of Adjustable Stiffness, Yu-Hung Lin

Open Access Dissertations

It is increasingly recognized that mechanical properties of substrates play a pivotal role in the regulation of cellular fate and function. However, the underlying mechanisms of cellular mechanosensing still remain a topic of open debate. Traditionally, advancements in this field have been made using polymeric substrates of adjustable stiffness with immobilized linkers. While such substrates are well suited to examine cell adhesion and migration in an extracellular matrix environment, they are limited in their ability to replicate the rich dynamics found at cell-cell interfaces. To address this challenge, we recently introduced a linker-functionalized polymer-tethered multi-bilayer stack, in which substrate stiffness …

Probing The Mechanism Of Oxalate Decarboxylase, Wen Zhu

Open Access Dissertations

Oxalate decarboxylase (EC 4. 1. 1. 2 OxDC) from Bacillus subtilis is a manganese-dependent enzyme that catalyzes the cleavage of the chemically inactive C-C bond in oxalate to yield formate and carbon dioxide. A mechanism involving Mn(III) has been proposed for OxDC, however no clear spectroscopic evidence to support this mechanism has yet been obtained. In addition, a recent study has shown that N-terminal metal binding site loop variants of OxDC were able to catalyze the oxidation of oxalate to yield hydrogen peroxide and carbon dioxide, which makes OxDc function as another oxalate degradation protein in the cupin superfamily, oxalate …

Thiol-Disulfide Exchange In Human Growth Hormone, Saradha Chandrasekhar

Open Access Dissertations

The biopharmaceutical industry has been growing at a tremendous rate, with sales of $63.6 billion 2012 in the US [1]. Nevertheless, the successful development of many protein drugs has been impeded by physical and chemical instabilities arising from their inherent chemical complexity and often leading to protein aggregation. The formation of non-native disulfide bonds is a common route to covalent aggregation of therapeutic proteins and other biologics [2, 3]. Disulfide bonds participate in hydrolytic and oxidative degradation reactions that form non-native disulfide bonds and other reactive species. The mechanisms responsible for protein aggregation are poorly understood and formulations are currently …

Race. Nation. Zombie: Imperial Masculinities Gazing At The Undead, Adryan Glasgow

Open Access Dissertations

This dissertation argues that zombie narratives have always been about white masculinity and that colonialism is the true living dead monster. The zombie is not the load-bearing signifier in these stories. It is the white men who act as representatives of empire that embody tropes and evolve. This dissertation examines the survivor masculinity in zombie films over time to see how hegemonic masculinity has adapted to a range of national crises. I argue that the failure of white masculinities in these films and novel is rooted in the limited ways of knowing inherent in the Imperial Gaze. Starting in the …

Climate Change Impacts On The Soil Erosion And Nutrient Losses In The Great Lakes Region, Wang Lili

Open Access Dissertations

Pollutants from non-point sources (NPS) have become the primary reason for water quality degradation in the Great Lakes region after great progress has been made in reducing point source pollution through the enforcement of total maximum daily loads (TMDL). Climate change may impact NPS pollutant transportation processes through influencing runoff

Tick-Flavivirus Interactions: Discovery Of Host Proteins That Are Affected In Virus Infection, Jeffrey Michael Grabowski

Open Access Dissertations

Grabowski, Jeffrey M. Ph.D., Purdue University, August 2015. Tick-Flavivirus Interactions: Discovery of Host Proteins That Are Affected in Virus Infection. Major Professors: Catherine A. Hill and Richard J. Kuhn.

Synthesis, Characterization, In Vitro Evalution, And Preclinical Profiling Of Β-Cyclodextrin Polyrotaxane Families For Use As Potential Niemann-Pick Type C Therapeutics, Christopher James Collins

Open Access Dissertations

Niemann-Pick Disease Type C (NPC) is a rare, autosomal recessive genetic disorder featuring a loss of proteins responsible for unesterified cholesterol (UC) trafficking through the late endosomes/lysosomes (LE/LY) of every cell of the body. Disruption of this pathway leads to abnormal accumulation and storage of UC and other lipids. A broad range of visceral and neurological symptoms result from this accumulation exhibiting a variable age of onset and a disease progression that is ultimately fatal. The disease has an incidence of approximately 1 in 120,000 live births and has no known effective treatment.

Habit Formation In A Rodent Model Of Alcoholism: Genetic Susceptibility, Alcohol-Specific Effects, And Pharmacological Manipulation, David Scott O'Tousa

Open Access Dissertations

Habit formation is a well-characterized process involving a shift from response-outcome as the leading driving force underlying action to a stimulus-response mechanistic process. It is hypothesized that a transition from goal-directed behavior to habitual behavior is driven by a transition of the bulk of cognitive load from neocortical toward lower neurological mechanisms. While many neurotransmitter systems have a demonstrated involvement in this process, the dopamine system is particularly implicated. Habit formation is assessed through the maintenance of extinction responding for an undesired, or devalued, outcome.

Microbial Controls On The Environmental Fate Of Carbon Nanomaterials, Timothy Dale Berry

Open Access Dissertations

Since the synthesis of the first carbon nanomaterials (CNM) 30 years ago, researchers and manufacturers have recognized the potential of these materials to transform the world. The unique physical properties and incredible resilience of these materials gives them countless applications and has led to significant increases in their production over the last decade. However, despite their growing prevalence, the properties and processes controlling the degradation of CNM in the environment remain poorly understood. The primary purpose of this dissertation is to examine the role of environmental microorganisms in degrading CNM and to elucidate which CNM properties and environmental processes represent …

Impacts Of Land-Atmosphere Interactions On Regional Convection And Rainfall, Yue Zheng

Open Access Dissertations

High resolution (1-10 km) numerical weather prediction (NWP) models face major challenges trying to improve representation of moist processes. In particular, simulating the interaction between the land surface and regional convection and rainfall is a source of uncertainties and presents three main barriers: (i) NWP models generally have simple land surface schemes, (ii) land-atmosphere coupling is not properly represented in models, and (iii) many assumptions made in deriving the theory of convective parameterizations are no longer valid at “gray scales” (e.g., 1-10 km). In this dissertation, interactions between land-surface heterogeneities, land-atmosphere coupling, and moist convection and related mesoscale circulations were …

First Graders As Sensitive Social Partners And Skilled Readers, Zaira R. Arvelo Alicea

Open Access Dissertations

This mixed methods dissertation is guided by a sociocultural framework and a pragmatist stance to contribute to early literacy scholarship about minority children. In particular, I explore the relationship between low socioeconomic status Puerto Rican children’s reading experience and their social cognition by: (1) assessing them through quantitative and qualitative measures that reveal their capacities in these areas at the end of their first grade year, and (2) documenting their reading experiences at home and at school through ethnographic qualitative methods. The analyses revealed significant positive correlations between the tests of reading and social understanding, a scarcity of conventional reading …

Creation And Validation Of The Critical Thinking About Sustainability Scale, Vivian Gregory Alexander

Open Access Dissertations

Alexander, Vivian G. Ph.D., Purdue University, December 2015. Creation and Validation of the Critical Thinking about Sustainability Scale. Major Professor: Yukiko Maeda.

Drug Delivery To Solid Tumors Via Polymeric Nanoparticles, Sara Ahmed

Open Access Dissertations

A main challenge in chemotherapy is to deliver an anti-cancer drug selectively to tumor and avoid off-target exposure to other body tissues and organs. Nanoparticles (NPs) have been considered a promising approach for tumor drug delivery, with popularity attributable to the famous “Enhanced Permeability and Retention effect”, where small particles enter tumor tissues through leaky vasculature and be retained there. Currently, the phagocytic clearance of NPs is avoided by coating NP surface with Polyethylene glycol (PEG). Although successful in prolonging NPs circulation, PEG prevents proper interaction of NPs with the target cells, known as “PEG dilemma”. Low molecular weight chitosan …

Tracking Plant Virus Infections Through Multiple Dimensions: A Search For Sources Of Nonpersistent Virus Vectors And Reservoirs At Local And Regional Scales, Gina Marie Angelella

Open Access Dissertations

My dissertation explores the ecology of aphid-vectored viruses in Midwestern cucurbits; in particular, it focuses on identifying source populations of vectors and virus reservoirs within fields and interactions of vector aphids with land cover surrounding and within fields. Initially, I identified the most commonly occurring viruses and aphid species associated with virus infections in pumpkin fields located across Indiana. This was done by assaying cucurbit leaf tissue with multiplex-rt-PCR targeting all four aphid-vectored, nonpersistent viruses found in cucurbits (papaya ringspot virus type-W, watermelon mosaic virus type-2, zucchini yellow mosaic virus, cucumber mosaic virus) and concurrently monitoring aphid species alightment in …

At Home In The Diaspora: Domesticity And Nationalism In Postwar And Contemporary Caribbean-British Fiction, Kim Caroline Evelyn

Open Access Dissertations

This project investigates the ways in which home is conceptualized and represented in sixty years of the literature of the Caribbean diaspora in Britain by balancing texts from the post-World War II period with contemporary texts and considering how the diaspora has been imagined and reimagined. Making a home of a diaspora—typically considered as a collection of scattered and ostracized migrants— requires a conceptual leap, act of agency, and, sometimes, a flight of imagination. Through the imagery of domesticity and the rhetoric of nationalism, literary analyses of representations of diaspora allow us to explore the imagined constructs of diasporic homes. …

A Meta-Analysis Of Prescription Stimulant Efficacy: Are Stimulants Neurocognitive Enhancers?, Marisa E. Marraccini

Open Access Dissertations

Prescription stimulant use for neurocognitive enhancement is a significant problem among college students with and without ADHD. The primary reason students report misusing stimulant medication is to enhance academic functioning. Given that increasing numbers of students are misusing prescription stimulants, it is critical to explore whether empirical findings support neurocognitive benefits of prescription stimulants. Hence, the primary purpose of this meta-analytic study was to examine the potential effects of prescription stimulants on cognitive functioning of adults with and without ADHD. A systematic search and retrieval process resulted in the calculation of effect sizes from 91 studies. Fourteen meta-analyses were conducted …

Distributions And Interactions In Three Groups Of Polar Marine Plankton, Alison Clare Cleary

Open Access Dissertations

Polar marine ecosystems are highly productive, with strong seasonal phytoplankton blooms, and high abundances of vertebrate predators. A key link between these phytoplankton and megafauna are the zooplankton, which package and transform phytoplankton biomass, making it available to the fish, mammals, seabirds, and other predators in the ecosystem. I investigated three groups of these important small eukaryotes. In the Bering Sea I analyzed the diet of three morphologically very similar congeners of Pseudocalanus copepods. The two copepod species with largely overlapping geographic ranges were found to have different diets, suggesting feeding differences may serve as a mechanism of niche partitioning …

Toward A Psychosocial Understanding Of Suicide In American Literature And Culture Of The 1990’S, Sara E. Murphy

Open Access Dissertations

As a means of rectifying the problematic absence of multidisciplinary scholarly work on suicide, this dissertation project interrogates suicide in American literature and culture of the 1990’s across disciplines within the humanities, medicine, and the social sciences. Utilizing a psychosocial approach to the study of suicide – that is, an understanding of suicide as produced both by one’s psychological development within and by one’s social relationship to his or her environment – I address what I have identified as a unique trifurcated suicide response that arose in American culture in the 1990’s as it emerged through major societal and legal …

Iron-Catalyzed Arylation Of Heterocycles And Transition-Metal Free C-N Bond Formation, John Joseph Sirois

Open Access Dissertations

The formation of carbon-carbon (C-C) and carbon-nitrogen (C-N) bonds is discussed and efforts towards expanding the known reactions of this type are the primary focus of this work. The iron-catalyzed arylation of aromatic heterocycles, such as pyridines, thiophenes and furans has been achieved. The use of an imine directing group allowed for the ortho-functionalization of these heterocycles with complete conversation in 15 minutes at °C. Yields up to 88% were observed in the synthesis of 15 heterocyclic biaryls. C-N bond formation is achieved using aryl Grignard reagents and N-chloroamines at -78 °C.

Life Vs. Unlife: Interspecies Solidarity And Companionism In Contemporary American Literature, Barnaby Mclaughlin

Open Access Dissertations

This dissertation explores the representations of interspecies relationships in contemporary American literature. In recent years, interdisciplinary attention, variously referred to under the umbrella categories of Posthumanism," "Human-Animal Studies," "Animality Studies," and "Critical Animal Studies," have called into question the anthropocentric traditions across multiple disciplines. However, much of this recent attention still focuses on animals in the abstract, which is to say that they rarely concern themselves with actual animals or our relationships to them. Even when a real animal manages to penetrate a text, such as Jacques Derrida's cat in the opening pages of The Animal That Therefore I Am …

Mensurative And Manipulative Experiments Test Effects Of Global Change Drivers On Greenhouse Gas Fluxes In Coastal Marshes, Rose Marie Martin

Open Access Dissertations

For centuries, coastal marshes have been subjected to anthropogenic stressors. Great expanses of coastal marshes were drained and filled to make way for development, and those that remained were diked and ditched, encroached upon by upland development, and used for agricultural purposes such as livestock grazing. Today, as the values and services coastal marshes provide to human society are understood, marshes are protected from direct degradation. However, especially in developed and densely populated estuaries such as Narragansett Bay, coastal marshes are subject to impacts including nutrient pollution and introduction of invasive species. Global climate change and associated sea level rise …

Design And Development Of Ph-Sensitive Peptides For Cancer Diagnostics, Ramona Cosmina Adochite

Open Access Dissertations

The design and development of pH-sensitive peptides for cancer diagnostics provides an opportunity to study and address fundamental questions of in vivo bio-distribution of pH-sensitive peptides, as well as developing new targeting imaging and therapeutic agents for acidic diseased tissue such as cancer, infections, ischemia, stroke and others.

The main goal of the work presented here is to investigate the following problems:

- Targeting of highly metastatic mammary tumors and spontaneous breast tumors in transgenic mice with fluorescently labeled pHLIPs® (pH (Low) Insertion Peptides) pHLIP variants;

- Direct imaging of pHLIP insertion and cargo translocation in vivo;

- Targeting …

The Application Of The Self Organizing Map To The Vehicle Routing Problem, Meghan Steinhaus

Open Access Dissertations

The Vehicle Routing Problem (VRP) is an �P-hard, combinatorial optimization problem. For �P-hard problems, there is no known polynomial time algorithm to solve these problems. Therefore, for many moderately sized problems, these problems cannot be reliably solved to optimality. This is the case with the VRP, where problem instances with over 100 cities are not easily solved using exact methods. Therefore, the majority of VRP research focuses on heuristics.

Artificial Neural Networks (ANNs) are inspired by the functions in the human brain. Researchers have applied ANNs across a wide range of problems with great success. Since solving the VRP relies …

Tracking Control For Non-Minimum Phase System And Brain Computer Interface, Yacine Boudria

Open Access Dissertations

For generations, humans dreamed about the ability to communicate and interact with machines through thought alone or to create devices that can peer into a person’s mind and thoughts. Researchers have developed new technologies to create brain computer interfaces (BCIs), communication systems that do not depend on the brain’s normal output pathways of peripheral nerves and muscles. The objective of the first part of this thesis is to develop a new BCI based on electroencephalography (EEG) to move a computer cursor over a short training period in real time. The work motivations of this part are to increase: speed and …