Digital Commons Network^™

Sexual Dimorphism In A Mouse Model Of Dry Eye Disease, Neal Mecum

Electronic Theses and Dissertations

Dry eye can result from multiple causes, including a reduction in the quantity or altered composition of tears. The lacrimal gland is the major supplier of the aqueous tear components, including water, electrolytes, and proteins. Reduced output from the lacrimal glands results in aqueous tear deficiency, a specific subclass of dry eye disease (DED) marked by inadequate tear volume. The prevalence of DED is 1.5-2 times greater in women than men, yet a comprehensive comparison of dry eye symptoms in male and female animals in an animal model of DED has not been performed. We excised the lacrimal gland to …

Modeling, Simulation, And Validation Of Process-Structure-Property Relationships In Fused Filament Fabrication, Aaron Grant

Electronic Theses and Dissertations

As additive manufacturing (AM) grows in popularity, the need for better simulation tools to predict the process-structure-property relationships of AM parts becomes ever more necessary to employ the technology in design of functional parts with varying degrees of complexity and performance requirements. Many simulation tools and techniques have been developed that aim to achieve this goal, and the main purpose of this research is to explore how well different simulation tools and modeling approaches can capture various AM-specific features such as inter-raster and end-of raster voids, and residual stresses induced by dissimilar rates of thermal expansion. Process simulation of fused …

Spruce Budworm Defoliation Dynamics And Its Influence On The Acadian Forest, Cen Chen

Electronic Theses and Dissertations

Spruce budworm (SBW; Choristoneura fumiferana (Clem.)) is the primary forest defoliator in North America. SBW defoliation has affected tens of millions ha of forests during its periodic outbreaks and caused severe growth reduction and mortality of spruce-fir (Picea-Abies) species. Evaluating these damaging effects of SBW defoliation requires understandings of the variation and dynamics of defoliation, as well as trees' variable responses to defoliation in consideration of various tree- stand-, and site-level factors. In this dissertation, we developed statistical models to 1) evaluate influences of SBW defoliation on spruce-fir stand dynamics of annual volume net growth, mortality, …

Utilization Of Low-Lime Calcium Silicate In Hydrated And Carbonated Cementitious Materials, Mohammad Rakibul Islam Khan

Electronic Theses and Dissertations

This study investigated the potential application of wollastonite as a cementitious material in both hydrated and carbonated binder systems. Wollastonite is naturally occurring low-lime calcium silicate (CaO.SiO₂) mineral with a substantially lower carbon footprint compared to the ordinary Portland cement (OPC). The first part of this work presented the application of wollastonite as partial replacement of OPC in traditional hydrated cement-concrete system. Second part of this work evaluated the properties of carbonation activated binder produced using wollastonite as the primary ingredient.

For the first part of the thesis, ground wollastonite with 3.5 µm and 9 µm mean particle …

Towards A Unified Disease Mechanism For Trna Synthetase-Mediated Peripheral Neuropathy, Emily L. Spaulding

Electronic Theses and Dissertations

Charcot-Marie-Tooth disease (CMT) is a debilitating inherited peripheral neuropathy resulting in progressive distal muscle atrophy and loss of sensation. CMT is genetically heterogeneous, with mutations in over 80 different genes leading to demyelinating or axonal forms. There are genetically similar subgroups, including the largest protein family implicated in the disease, the tRNA synthetases (ARSs). ARSs are responsible for aminoacylation of tRNAs during translation and are therefore ubiquitously expressed and essential proteins. Dominant mutations in at least five ARSs cause axonal forms of CMT. How mutations in ARSs cause CMT is unclear, however, the similar clinical presentation of patients suggests shared …

Validation Of A Fluorescence-Based Bacteria Enumeration And Viability Determination Method Using Image Cytometry, Matthew R. Hodgkin

Electronic Theses and Dissertations

Craft beer production in the United States has been increasing significantly in recent years. As production and participation in the industry increases, so have consumer demands for more beer options. Breweries have met this call with experimentation of ingredients in their beer and also the styles they brew. One such beer, the sour beer, is an example of this experimentation and new product development. Sour beers are a style that differ from most other beers by how they are manufactured. Instead of being fermented with only yeast, both a lactic acid-producing bacteria and yeast are used. With increased competition amongst …

An Investigation On The Effects Of Cellulose Nanofibrils On The Performance Of Cement Based Composites, Hosain Haddad Kolour

Electronic Theses and Dissertations

Cellulose nanofibrils (CNFs) are hydrophilic biodegradable nanoparticles (typically, less than 0.2 mm in length and 20-50 nm in width) that can be extracted from various plants, trees, and recycled paper stock. Their low density, low toxicity, relatively low cost, high aspect ratio, and high specific surface enable functionalization. In this work, the effects of CNFs on selected properties of cement paste, mortar, and concrete were investigated. For the cement pastes, rheology tests using a simple rheometer showed a reduction in workability as CNF dosage increased. Free shrinkage tests showed an increase in shrinkage at high w/c ratios but a decrease …

A Laboratory Investigation Of Cement Based Materials With Cellulose Nanofibers, Parivash Takasi

Electronic Theses and Dissertations

Cellulose Nanofibers (CNFs) are used as additives in cement-based products to modify their properties. Recent studies about the effects of CNFs on cement paste showed inconsistent results for several different important properties, including compressive strength and free shrinkage. There is reason to believe that the unsystematic results of the compressive strengths were affected by the lack of uniform dispersion of CNFs. As a potential remedy, two different mixing methods were applied. The first method used a basic mixer, but aggregates were added to the cement paste mixture to improve the blending process. The second method utilized a high-speed shear mixer …

The Potential For Dickeya Dianthicola To Be Vectored By Two Common Insect Pests Of Potatoes, Jonas K. Insinga

Electronic Theses and Dissertations

Dickeya dianthicola (Samson) causing blackleg and soft rot was first detected in potatoes grown in Maine in 2014. Previous work has suggested that insects, particularly aphids, may be able to vector bacteria in this genus between plants, but no conclusive work has been done to confirm this theory. In order to determine whether insect-mediated transmission is likely to occur in potato fields, two model potato pests common in Maine were used: the Colorado potato beetle (Leptinotarsa decimlineata Say) and the green peach aphids (Myzus persicae Sulzer). Olfactometry and recruitment experiments evaluated if either insect discriminates between infected and …

A Qualitative Representation Of Spatial Scenes In R2 With Regions And Lines, Joshua Lewis

Electronic Theses and Dissertations

Regions and lines are common geographic abstractions for geographic objects. Collections of regions, lines, and other representations of spatial objects form a spatial scene, along with their relations. For instance, the states of Maine and New Hampshire can be represented by a pair of regions and related based on their topological properties. These two states are adjacent (i.e., they meet along their shared boundary), whereas Maine and Florida are not adjacent (i.e., they are disjoint).

A detailed model for qualitatively describing spatial scenes should capture the essential properties of a configuration such that a description of the represented objects …

Evaluating The Occurrence Of Age-Related Peripheral Neuropathy In Het3 Mice And Development Of A Whole Tissue Imaging Technique For Analyzing Total Innervation In The Subcutaneous Adipose Depot, Jake Willows

Electronic Theses and Dissertations

Adipose tissue can be characterized as either being a white (energy storing) depot or a brown (energy expending) depot and both have been found to contain dense networks of neural innervation. This adipose nerve supply regulates numerous metabolic functions and likely plays an important role in the function of adipose blood vessels. Recently our lab has shown in the C57BL/6 mouse model that peripheral neuropathy, or the dying back and dysfunction of the nerves in the superficial tissues such as the skin, can extend into the subcutaneous adipose tissue in conditions commonly associated with the neuropathic phenotype (i.e. diabetes, obesity, …

Student Retention, Coping, And Communication: A Study Of Student Responses To A Common Read At A Small Liberal Arts College, Debbie Cunningham

Electronic Theses and Dissertations

College student retention has been researched for over half a century. Much of the research about student retention has examined easily quantifiable factors, such as demographic variables, or presumably objective measures of student readiness, such as SAT scores. The results of these types of studies demonstrate the complexities of retention and attrition and underscore the importance of examining retention within the local contexts of institutions.

This study adopts a communication perspective to examine the intersection of three critical constructs: student retention, student writing, and identity. By observing the ways in which students constitute their identities in essays submitted as part …

The Effects Of Sediment Acidification And Temperature On The Immune Capacity Of The Atlantic Jackknife (Razor) Clam (Ensis Leei M. Huber, 2015), Brian Preziosi

Electronic Theses and Dissertations

Sediment acidification has been shown to negatively impact clams of economic importance such as the soft-shell clam, Mya arenaria Linnaeus, 1758, and hard clam, Mercenaria mercenaria (Linnaeus, 1758). Effects of sediment acidification on razor clams, including the Atlantic jackknife clam Ensis leei M. Huber, 2015, are unknown. E. leei has been identified as a species with potential for aquaculture operations on the New England coast. E. leei may be resilient to acidification and thus persist in acidified sediments where other clams cannot. To this end, the impact of acidified surface sediment on the internal immune capacity of adult (mean shell …

Rapid Prototyping To Roll-To-Roll Manufacturing Of Microfluidic Devices, Amber Lee Boutiette

Electronic Theses and Dissertations

Microfluidics constitutes a widely applicable field of enabling technologies with great potential to revolutionize healthcare and biotechnology. The ability to miniaturize and parallelize processes with microfluidics is seen as a solution for many problems with diagnostics technologies and accessibility. Unfortunately, fabricating microfluidics often require extremely expensive, time consuming, and specialized high-precision methods, making both prototyping and commercial-scale mass manufacturing difficult to accomplish. In this work, we evaluate the feasibility of using a unique roll-to-roll (R2R) micropatterning manufacturing process coupled with Additive Manufacturing (3D printing) to rapidly prototype and produce microfluidic devices at high-volume on film or paper backings for applications …

The Effects Of Timber Harvesting On Blacklegged Tick (Ixodes Scapularis) Abundance And Infection Prevalence, Christine Conte

Electronic Theses and Dissertations

The northern range of the blacklegged tick (Ixodes scapularis) is expanding, and with it, the pathogens it vectors, including Borrelia burgdorferi, Anaplasma phagocytophilum, and Babesia microti. As the range of I. scapularis expands, understanding the impacts of land management practices on tick habitat and the wildlife communities that impact pathogen transmission may lead to vector-borne disease management. To determine the effects of timber harvesting on tick abundance and pathogen prevalence, for two consecutive years, we conducted an observational field study at five study sites in Hancock County, Maine, a hotspot of Lyme disease incidence in humans. Each study site consisted …

Bridging The Gap: Including Cultural Science In Post-Secondary Education To Enhance Learning Within Sciences For Native And Non-Native Students, Tish Carr

Electronic Theses and Dissertations

Until seven years ago, there were few mechanisms in place within theWabanaki communities to keep Native students connected from middle school through college if an interest was sparked in the science, technology, engineering and math (STEM) fields. On average, less than 50 percent of Native Students graduate from high school. The past six years, the Wabanaki Youth in Science program (WaYS) has become a "bridge" for students to learn more at the secondary level about STEM fields. The next phase in the academic journey to aid student learning is to develop a model educational program that will increase Native youth …

Cellulose Nano-Composites For Performance Enhancement Of Portland Cement-Based Materials, Kavya Shirisha Kamasamudram

Electronic Theses and Dissertations

Cellulose Nano Fibrils (CNF) having a high aspect ratio, elastic modulus, tensile strength and reactive surface area for functionalization was considered as a promising nanomaterial for improving chemo-mechanical properties of the cementitious matrixes. CNFs are typically less than 0.2 mm in length and 50nm in width that can be extracted from plants and trees. Overall, in this thesis the study is broadly divided in to three stages: (i) In the first stage, a hybrid silica coated CNF (Si-CNF) was developed and investigated for its effects on cement based systems in addition to Pure CNF (PCNF). (ii) In the second stage, …

Teacher Professional Development Using Iterative Inquiry-Based Chemistry Workshop, Clint Eaton

Electronic Theses and Dissertations

The National Science Teachers Association recommends that all science teachers use instructional practices that support scientific inquiry, in alignment with Next Generation Science Standards that integrate content with inquiry practices. However, research has shown that many science teachers do not have robust understandings and experiences of scientific inquiry or may not manifest it successfully in their classroom practices. This study investigates teachers’ learning of inquiry elements including scientific communication skills and evidence and reasoning to support claims, through the use of iterative inquiry-based chemistry activities. The study was conducted during Professional Development (PD) in the context of a rural Mathematics …

Mercury Concentrations In Aquatic Insects Of Two Maine Coastal Streams: Temporal Patterns Of Mercury In Aquatic Insect Biosentinels And Implications For Methylmercury Flux, Megan C. Hess

Electronic Theses and Dissertations

Mercury (Hg) is a widespread water quality concern because it is a potent neurotoxin that biomagnifies through food webs, posing risk to biota higher in the food chain. Aquatic insects are effective for characterizing relative Hg risk in freshwater food webs because they live and forage in aquatic habitats where Hg is present and converted to its more toxic bioavailable form, methylmercury (MeHg). Specifically, dragonfly nymphs (Odonata) are increasingly being used as a Hg bioindicator. Therefore, I (Chapter 1) conducted a systematic review of the literature to evaluate the utility of dragonflies as biosentinels for Hg. Dragonfly nymphs have been …

Nonverbal Communication And Its Role In Building Rapport: A Mixed Methods Study Of K-12 Teachers, Barbara M. Moody

Electronic Theses and Dissertations

This study set out to measure the impact of nonverbal communication (NVC) teacher behaviors on student perceptions of rapport and to determine which of these behaviors were conscious. Six teachers at three grade levels were participants in the study. The NV behaviors of teachers were quantified and their effect on student perceptions of rapport was measured by student surveys. Teachers’ awareness of their NVC skills was established thorugh an analysis of interviews. The mixed-methods convergent parallel methodology contributed to a rich collection of data that was analyzed using multiple strategies. The literature provides extensive evidence that NVC behaviors contribute to …

Effects Of High Pressure And Sous-Vide Processing On Quality Of Atlantic Sea Scallops (Placopecten Magellanicus), Dhriti Nayyar

Electronic Theses and Dissertations

Sous-vide is the cooking of vacuum-sealed foods at precise temperatures in a water bath. Vacuum packaging and cooking at lower temperatures offer multiple benefits to maintain the nutritive and sensory value of foods in comparison to traditional cooking methods. Sea scallops are high-value products that have a very short refrigerated shelf-life (<7 >days). High pressure processing (HPP) may facilitate the development of convenient-to-use, high quality, refrigerated scallop products for sous-vide applications to be sold in retail and foodservice facilities. The objectives of this research were to evaluate the effects of HPP and subsequent sous-vide cooking on the 1) physicochemical and …

Stress Tolerance Of An Invasive Alga, Grateloupia Turuturu, And Studies Of Bacterial Communities Of Fucus Spp. Along An Intertidal Stress Gradient, Kyle Arin Capistrant-Fossa

Electronic Theses and Dissertations

Maine’s intertidal zones are ecologically and economically important habitats that face new anthropogenic perturbations (e.g., invasive species introductions, commercial activities, climate change). For example, I discovered the invasive red alga Grateloupia turuturu for the first time in Maine (Damariscotta Estuary) in 2017, over 200 km north of its last known location. Coastal facilities often employ biosecurity protocols in an attempt to limit the spread of such invasive species, but their effectiveness against G. turuturu was unknown. This study examined susceptibility of G. turuturu and some native macroalgae (e.g., Mastocarpus stellatus, Palmaria palmata) to a common bleach-based biosecurity protocol (50 ppm …

Hydro-Climatic Dynamics Of Lake Watershed Systems In A Changing Climate, Mussie Tekie Beyene

Electronic Theses and Dissertations

In the northern hemisphere, winter climate conditions are showing dramatic year-to-year swings. To date, implications of a changing winter climate pattern on individual or regional lakes are poorly understood, particularly in cold regions where seasonal ice appears on lake surfaces. This dissertation investigates the significance of yearly winter climate condition on the health and function of freezing lakes by modeling and characterizing the response of lake ice phenology (and related socio-ecological systems) to winter weather-climate variability. In Chapter 2, several case studies on winter limnology are reviewed to develop a tentative socio-ecological framework that demonstrates the local and regional implications …

Theory Of Lexicographic Differentiation In The Banach Space Setting, Jaeho Choi

Electronic Theses and Dissertations

Derivative information is useful for many problems found in science and engineering that require equation solving or optimization. Driven by its utility and mathematical curiosity, researchers over the years have developed a variety of generalized derivatives. In this thesis, we will first take a look at Clarke’s generalized derivative for locally Lipschitz continuous functions between Euclidean spaces, which roughly is the smallest convex set containing all nearby derivatives of a domain point of interest. Clarke’s generalized derivative in this setting possesses a strong theoretical and numerical toolkit, which is analogous to that of the classical derivative. It includes nonsmooth versions …

The Rise And Decline Of The Cooperative Commonwealth Federation In Ontario And Quebec During World War Ii, 1939 - 1945, Charles A. Deshaies

Electronic Theses and Dissertations

The Cooperative Commonwealth Federation (CCF) was one of the most influential political parties in Canadian History. Without doubt, from a social welfare perspective, the CCF helped Canada build and develop an extensive social welfare system across Canada. The CCF’s major contributions to Canadian social welfare policy during the critical years following the Great Depression has been justly credited to the party. This was especially true during the Second World War when the federal Liberal government of Mackenzie King adroitly borrowed CCF policy planks to remove the harsh edges of capitalism and put Canada on the path to a modern welfare …

Northern Conifer Forest Management: Silvicultural, Economic, And Ecological Outcomes From 65 Years Of Study, Maren Granstrom

Electronic Theses and Dissertations

While forest managers once sought primarily to produce sustainable revenue from harvests, there is now growing value placed on non-timber outcomes like wildlife habitat, climate adaptability, and carbon storage. When deciding how to manage land for the future, foresters and landowners must assess the many outcomes of forestry activities and be aware of the tradeoffs inherent to achieving different goals. Given the slow growth of trees relative to other commercial crops, it is rare to have the continuity of land ownership, researchers, and funding needed to follow a stand for a full rotation or to observe a tree from recruitment …

Fish Passage And Hydropower: Investigating Resource Agency Decision-Making During The Ferc Hydropower Relicensing Process, Sarah Vogel

Electronic Theses and Dissertations

Hydropower dams represent a significant challenge for the successful migration of sea-run fish, many species of which are in decline. Most hydropower dams in the United States are regulated by the Federal Energy Regulatory Commission (FERC), an independent federal agency responsible for granting 30 to 50-year licenses to projects for their continued operation. Licenses typically include conditions for the conservation of sea-run fish such as fish passage construction, operational changes, monitoring of effectiveness, and other mitigative conditions. While FERC remains the primary authority in licensing, the current regulatory framework stipulates input from other federal and state resource and regulatory agencies, …

Elucidation Of The Factors Affecting The Production And Properties Of Novel Wood Composites Made Using Renewable Nanomaterials As A Binder, Ezatollah Amini

Electronic Theses and Dissertations

A novel application of cellulose nanofibrils (CNF) as a binding agent is proposed. In this work the utilization of CNF as a complete replacement for the conventional resin-adhesives in the formulation of particleboard (PB) was evaluated. PB panels with varying CNF contents and target densities were produced using a two-step (i.e. cold and hot) pressing process. For initial evaluation, the mechanical and physical properties of the manufactured panels were determined. The need to remove a considerable amount of water from the wood particle (WP)-CNF mixture during cold pressing, motivated the study of the furnish dewatering behavior. Dewatering was assessed through …

A Longitudinal Study Of Mammograms Utilizing The Automated Wavelet Transform Modulus Maxima Method, Brian C. Toner

Electronic Theses and Dissertations

Breast cancer is a disease which predominatly affects women. About 1 in 8 women are diagnosed with breast cancer during their lifetime. Early detection is key to increasing the survival rate of breast cancer patients since the longer the tumor goes undetected, the more deadly it can become. The modern approach for diagnosing breast cancer relies on a combination of self-breast exams and mammography to detect the formation of tumors. However, this approach only accounts for tumors which are either detectable by touch or are large enough to be observed during a screening mammogram. For some individuals, by the time …

Identification Of Chromatin Regulators Perturbed In Hematopoietic Stem And Progenitor Cell Aging, Eraj S. Khokhar

Electronic Theses and Dissertations

As lifespan is increasing globally, there is a critical need to identify strategies to extend healthspan and prevent chronic diseases into older age. The long-term goal of my research is to identify novel strategies to ameliorate aging-induced decline in hematopoietic stem cell (HSC) function. HSCs give rise to all mature blood and immune cells. With age, HSCs undergo defects in their differentiation ability which correlates with a decline in immune function. Comprehensive knowledge of gene regulatory and epigenetic mechanisms underlying this defect is a barrier to developing therapies to ameliorate aging-associated decline in HSC function. Therefore, my project focuses on …