Digital Commons Network^™

Effects Of Developmental Exposures Of Two Emerging Environmental Toxicants On Estrogen-Sensitive Endpoints, Corinne E. Hill

Masters Theses

Thousands of synthetic chemicals have been released into the environment, causing widespread exposures of wildlife and humans alike. Some of these chemicals are known to disrupt aspects of hormone action thus inducing abnormalities in endocrine tissues and organs. Bisphenol S (BPS) and tetrabromobisphenol A (TBBPA), two largely unstudied chemicals commonly used in consumer products, are suspected to have endocrine disrupting properties based on their similar chemical structures to known endocrine disrupting chemicals (EDCs). To determine whether developmental exposure to BPS or TBBPA induced abnormalities in the ovary, mice were administered oil, BPS or TBBPA during pregnancy and lactation. The ovaries …

Associations Between Anxiety And Attention In Laboratory-Housed Rhesus Macaques (Macaca Mulatta), Lauren E. Hobbs

Masters Theses

Previous studies completed with humans have revealed insight into the effects of anxiety on attention tasks such the dot-probe task, but there is little information about such effects on non-human primates. This study aimed to assess whether anxiety or anxious behaviors would impact rhesus macaque performance on a three stimuli paradigm similar to the dot-probe task. Utilizing images of conspecifics (strong threat, mild threat, and neutral), eight monkeys were video recorded completing a task that required them to slide two doors, which held these images, to the side to obtain a treat. We hypothesized that behavioral phenotype (high or low …

Spray Fabrication Of Layer-By-Layer Antimicrobial N-Halamine Coatings, Anna Denis-Rohr

Masters Theses

Antimicrobial coatings in which the active agent (e.g. N-halamine) can regenerate activity represent a promising way to prevent microbial cross-contamination. A reported method for applying coatings containing antimicrobial N-halamines is layer-by-layer (LbL) application of polyelectrolytes, which form N-halamines upon cross-linking. Prior reports on dip layer-by-layer (LbL) fabrication have demonstrated the potential of this coating technology; however, spray LbL fabrication would enable more rapid coating and represents a more commercially translatable application technique. In this work, dip and spray LbL methods were used to coat polypropylene (PP) with N-halamine containing bilayers consisting of cross-linked polyethylenimine (PEI) and poly(acrylic acid) (PAA). Further …

Dissolution, Ocean Acidification And Biotic Extinctions Prior To The Cretaceous/Paleogene (K/Pg) Boundary In The Tropical Pacific, Serena Dameron

Masters Theses

The several million years preceding the Cretaceous/Paleogene (K/Pg) boundary has been the focus of many studies. Changes in ocean circulation and sea level, extinctions, and major volcanic events have all been documented for this interval. Important research questions these changes raise include the climate dynamics during the warm, but not hot, time after the decay of the Late Cretaceous greenhouse interval and the stability of ecosystems prior to the mass extinctions at the end-Cretaceous.

I document several biotic perturbations as well as changes in ocean circulation during the Maastrichtian stage of the latest Cretaceous that question whether the biosphere was …

Experimental Tests Of Road Passage Systems For Reducing Road Mortalities Of Freshwater Turtles, Derek T. Yorks

Masters Theses

Roadways are a pervasive feature of northeastern landscapes and can be a significant source of mortality for turtles. Until recently, little has been known about the design requirements for successful under-road passages for turtles and other wildlife to move safely between bisected habitat patches. At outdoor laboratories, using a factorial experimental design, we examined movements in response to varying light levels, and barrier opacity for painted turtles (Chrysemys picta, n=833), Blanding’s turtles (Emydoidea blandingii, n=49), and spotted turtles (Clemmys guttata, n=49). Additionally, we examined tunnel size, tunnel entrance design, and artificial lighting for painted …

Thermocycle-Regulated Wall Regulator Interacting Bhlh Encodes A Protein That Interacts With Secondary-Cell-Wall-Associated Transcription Factors, Ian P. Whitney

Masters Theses

Lignocellulosic biomass is one of the most abundant raw materials on earth that can be utilized to created carbon-neutral biofuels as a replacement for conventional fossil fuels. In order to create ideal energy crops, the regulation and deposition of cell wall polysaccharides must first be fully understood. Improved understanding of cell wall regulation will enable selection of traits that can optimize biofuel feedstocks. Herein, I utilize the grass model system Brachypodium distachyon in order to understand the transcriptional regulation of secondary cell wall deposition. Gene expression profiling was used to elucidate transcription factors that regulate secondary cell wall biosynthesis. Through …

Effects Of Early Spring And Preventative Snow Mold Fungicide Applications On Dmi Sensitive And Insensitive Populations Of Sclerotinia Homoeocarpa, Marvin D. Seaman

Masters Theses

Dollar spot, caused by the pathogen S. homoeocarpa (F.T. Bennett), is a common disease that infects a wide variety of turfgrasses all over the world. Yet it is significant problem on golf course putting greens and fairways consisting of creeping bentgrass (Agrostis stolonifera L.) and annual bluegrass (Poa annua L.). It is active in a wide variety of environmental conditions ranging from 16-30˚C but favors warm, humid days, followed by cool nights. Sclerotinia homoeocarpa overwinters as dormant mycelium in dead plant tissue. In the spring, germinating mycelia begin to infect leaf blades causing foliar lesions, which then spread …

Efficient Irrigation For Recreational Turfgrass In New England: Evapotranspiration And Crop Coefficients, James W. Poro

Masters Theses

As water demand increases it will become more imperative for golf course superintendents, landscape managers, and other industry professionals to improve water use efficiency in the management of recreational turfgrass. Scheduling irrigation according to actual turfgrass evapotranspiration rates (ET_T) is an integral component of efficient irrigation practices. Impracticality of field derived ET_T for industry use, however, directs the need of weather station derived reference (predicted) evapotranspiration (ET₀). To accurately predict (estimate) ET_T of turf and other crops, scientifically derived landscape (crop) coefficients (K_c values) are used in conjunction with mathematical models that incorporate …

Thermo-Responsive Poly(N-Isopropylacrylamide) And Its Critical Solution Temperature Type Behavior In Presence Of Hydrophilic Ionic Liquids, Purnendu K. Nayak

Masters Theses

Thermo-responsive homopolymer poly(N-isopropylacrylamide), is a widely studied and used polymer. Our recent observations on thermal behavior of aqueous solutions of this polymer requires a short overview of existing results in order to understand the formation of different phases, both stable and unstable with the addition of hydrophilic Ionic liquids (ILs) 1-Butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF₄]), 1-Butyl-3-methylimidazolium acetate ([BMIM][OAc]) and 1-Butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) to the system. PNIPAM is soluble in cold water due to its inter- and intramolecular hydrogen bonding but phase separates upon heating at T > 32 , which is its lower critical solution temperature (LCST). PNIPAM exists in an …

Live Well Springfield – A Community Transformation Movement: Evaluation Of The Live Well Springfield Website, Jesse A. Mushenko

Masters Theses

The Live Well Springfield (LWS) movement is a collaborative effort of partner organizations in Springfield, Massachusetts. The project promotes healthy living by increasing knowledge and awareness of food and physical activity. A key LWS strategy was the creation of a website to function as an information hub. In addition to local event and health information, the website features 16 narratives depicting residents practicing healthy lifestyle choices, designed to encourage community engagement. To date, there has been no evaluation of the website’s reach and effect.

A mixed methods approach, surveys and focus group discussions, was designed to collect data from people …

Trends In Human-Wildlife Interactions As Related To Land Use And Human Density In Massachusetts, Michael A. Huguenin Jr

Masters Theses

We conducted a study of human-wildlife interactions in Massachusetts, USA between April 2010 and May 2012. Our objectives were to (1) compile and summarize public-generated reports on human-wildlife interactions across Massachusetts; (2) evaluate reports based on species, public concerns, and seasonal distribution; and (3) evaluate public perceptions of human-wildlife interactions. We collected unsolicited reports of human-wildlife interaction submitted to the Massachusetts Division of Fisheries and Wildlife (MDFW) through phone calls, emails, and face-to-face communications from the public. We received 2,730 reports from 332 of 351 towns in Massachusetts regarding 76 different wildlife species ranging from moose (Alces alces) …

Eneterotoxigenic Bacillus Cereus And Bacillus Thuringiensis Spores In U.S. Retail Spices, Upasana Hariram

Masters Theses

Bacillus cereus is a ubiquitous organism and a potential foodborne pathogen that can cause two types of gastrointestinal diseases: emesis and diarrhea. The emetic syndrome is caused by a heat and acid stable peptide toxin that is pre-formed in food, while the diarrheal syndrome is associated to two 3-protein, heat labile enterotoxin complexes that are formed in the intestine after ingestion of the organism. There are many reports on the isolation and characterization of Bacillus cereus from various foods, however there are no studies on the levels, toxigenicity and physical characteristics of B. cereus isolated from U.S. retail spices. …

Two Regulatory Aspects Of Ino1 Transcription In Yeast, Tschen-Wei Chang

Masters Theses

This study focuses on understanding the mechanisms of expression control of a phospholipid biosynthetic gene, INO1. This study also includes investigation into transcriptional regulation of SNA3, a gene in tandem upstream of INO1.

INO1 expression is a prevailing model for transcription studies. INO1 is repressed under growth conditions with inositol and derepressed by two transcription activators, Ino2 and Ino4, when inositol is absent. Coordination of the centromeric binding factor, Cbf1, with Ino2 and Ino4 is required for efficient derepression of INO1. Transcription of the INO1 adjacent SNA3 gene is also influenced by inositol. INO1 and SNA3 are …

Ant (Hymenoptera: Formicidae) Assemblages In Three New York Pine Barrens And The Impacts Of Hiking Trails, Grace W. Barber

Masters Theses

Ants are ecologically important, environmentally sensitive, widespread, and abundant, yet ant assemblages of many habitats remain poorly understood. Ants in inland barrens of New York State (NY) barely have been studied, but the limited data suggest such habitats are likely to support uncommon ant species and high species density for the region. To increase knowledge of these assemblages, I systematically collected ants from three inland barrens systems in NY, to create species lists and measure species density. I also investigated how hiking trails — a common man-made disturbance — may be impacting ant assemblages in these early-successional, disturbance-dependent ecosystems. My …

Rationalizing Nanoemulsion Formation For Encapsulation, Protection And Delivery Of Bioactive Food Components, Ying Yang

Doctoral Dissertations

The objective of this thesis was to design and develop novel food-grade nanoemulsion-based delivery systems for the encapsulation, protection and delivery of lipophilic bioactive food components. These delivery systems could be widely applied in aqueous-based fortified food products, such as beverages, salad dressing and yogurt etc. Both the low- and high-energy methods could be used for fabricating nanoemulsions (r < 100 nm). The microfluidization method could form nanoemulsions at low surfactant-to-oil ratios (SOR < 0.1), but it required the use of high-energy inputs and expensive equipment. On the other hand, the spontaneous emulsification method could also form ultrafine emulsions and moreover it was simple and inexpensive, but it required much higher surfactant-to-oil ratios (SOR > 0.5) for forming nanoemulsions. Q-Naturale^® is a natural food-grade surfactant, which is got from the bark of the Quillaja saponaria Molina tree. By using high pressure homogenization (microfluidization), Q-Naturale^® could form relatively small droplets (d < 200 nm) at low surfactant-to-oil ratios (SOR < 0.1), but the droplets were not as small as those produced using Tween 80 under similar conditions (d < 150 nm). The emulsions formed by using Q-Naturale^{® …}

Experimental And Modeling Studies On The Formulation Of Stable Lipid Nanoparticle Dispersions, Yihui Yang

Doctoral Dissertations

This thesis presents both experimental and modeling studies on the formulation of stable lipid nanoparticle dispersions. A population balance equation (PBE) model was developed for prediction of the average polymorph content and aggregate size distribution to better understand the undesirable SLN aggregation behavior. Experimental and modeling studies showed that the polymorphic transformation was the rate determining step for my system, SLNs with smaller initial size distributions aggregated more rapidly, and aggregates contained particles with both alpha and beta crystals. Next the effect of different liquid carrier oils on the crystallization and aggregation behavior of tristearin NLC dispersions was investigated. I …

The Effect Of Thermoregulation And Roads On The Movements And Habitat Selection Of Moose In Massachusetts, David W. Wattles

Doctoral Dissertations

Massachusetts, U.S.A. is located along the southern boundary of the geographic range of moose (Alces alces) in North America. This is an atypical environment for moose, because of its extremely high levels of human development and high year-round temperatures, which are possibly at the limits of moose physiological tolerances. I investigated the role of these two factors on moose movements and habitat selection to determine how human development of the landscape and temperature influence moose occupation of this extreme environment. In addition, the response of moose to these factors provides insights into the influence of development and temperature …

Mechanisms For Extracellular Electron Exchange By Geobacter Species, Jessica A. Smith

Doctoral Dissertations

Understanding the mechanisms for microbial extracellular electron exchange are of interest because these processes play an important role in the biogeochemical cycles of both modern and ancient environments, development of bioenergy strategies, as well as for bioremediation applications. Only a handful of microorganisms are capable of extracellular electron exchange, one of the most thoroughly studied being the Geobacter species. Geobacter species are often the predominant Fe(III) reducing microorganisms in many soils and sediments, can exchange electrons directly via interspecies electron transfer, and can both donate or accept electrons with a wide variety of extracellular substrates including the electrode of a …

The Role Of The Extracellular Matrix In Mediating Muscle Soreness, Karen L. Riska

Doctoral Dissertations

The goal of this dissertation was to examine the role of the extracellular matrix (ECM) in muscle soreness. Study 1 examined how the disruption of the ECM from a minor surgery (e.g. muscle biopsy) affected muscle soreness. Study 1 showed that soreness levels increased at 24 h post-biopsy compared to baseline and resolved within 96 h. However, the level of muscle soreness at 24 h post-biopsy (20 mm) was lower than that reported for performing a strenuous and naïve exercise (40–80 mm). These results will help review boards at institutions where muscle biopsies are performed understand how a muscle biopsy …

Prediction Of Emulsion Drop Size Distributions With Population Balance Equation Models To Enable Emulsified Product Design, Shashank Maindarkar

Doctoral Dissertations

Oil-in-water emulsions are ubiquitous dispersed phase systems with diverse applications in consumer products, processed foods, and the pharmaceutical industry. Emulsion formulation variables and process operating conditions both impact the drop size distribution, a key property that influences emulsion rheology, stability, texture, and appearance. A typical emulsified product requires the drop size distribution to be maintained within acceptable limits. Due to a lack of quantitative understanding, emulsified products are currently manufactured by combining a broad knowledge of previous product formulations with empirical scientific experimentation. An alternative to trial-and-error experimentation is to utilize a suitable mathematical model to predict the drop size …

Cell Adhesion Biophysics On Dynamic Polymer Constructs, Andreas Kourouklis

Doctoral Dissertations

The biophysical characteristics of cell adhesion from single protein to cell length scales have primarily been studied using purely elastic substrates. However, natural extracellular matrix (ECM) is viscoelastic and contains mobile components. In this work, we combined chemistry and cell biology tools to design and characterize laterally mobile viscoelastic polymer films that promote receptor-specific cell adhesion. Moreover, we used amphiphilic block copolymers that are end-labeled with RGD peptide ligands to allow for integrin-mediated cell adhesion. The addition of a trace hydrophobic homopolymer in the supported bilayer block-copolymer films is used to tune the lateral mobility of the films. NIH 3T3 …

Agricultural Waste Remediation And H2 Production By Hyperthermophilic Heterotrophs: Bioinformatics, Taxonomy, And Physiology, Sarah A. Hensley

Doctoral Dissertations

In the United States, nearly 35 million tons of food waste are delivered to landfills and wastewater treatment plants for disposal each year. This places a burden on landfills and the environment through the introduction of foreign chemicals. Utilizing hyperthermophilic heterotrophs for waste treatment in a consolidated bioprocess could potentially remediate these organics, increase reaction rates, kill pathogens, produce a bioenergy product (H₂), and lower costs relative to mesophilic waste treatment options. However, it is unknown how various agricultural waste streams will affect hyperthermophilic growth and metabolite production. We investigated Thermococcales species for this purpose. Specifically, we chose …

A Novel Population Of Natural Killer Cells Plays A Critical Role In The Depletion Of Splenic B2 B Cells During Experimental African Trypanosomiasis, Deborah Frenkel

Doctoral Dissertations

Loss of humoral immune competence in T. brucei-infected mice is associated with the apoptotic depletion of splenic transitional, marginal zone and follicular B cells as well as a depletion of CD8⁺ T cells. This occurs rapidly after infection and impairs responses to vaccine antigens in addition to responses to newly arising VSG antigenic variants, leading to uncontrolled parasite growth and death of the infected mice. Infection-induced B2 B cell and CD8⁺ T cell loss requires the presence of a novel population of natural killer (NK) cells and is mediated by a perforin-dependent process consistent with perforin- and …

Plantar Pressure, Cutaneous Sensation And Stochastic Resonance: An Examination Of Factors Influencing The Control And Perception Of Posture, Michael A. Busa

Doctoral Dissertations

The goal of this dissertation was to understand how people control posture in the context of sensory loss. To do so we explored three potential influences on the detection of external information and how they relate to the control of posture and perception of body orientation: 1) does changing posture alter the forces under the foot, and do these changes impact the ability to detect external vibrations? 2) Does decreasing the temperature of the foot influence the ability to detect external vibrations, the perception of body orientation, and the control of posture? And 3) does stochastic resonance (SR) improve the …

Layer-By-Layer Antimicrobial N-Halamine Polymer Coatings For Food Contact Materials, Luis J. Bastarrachea Gutierrez

Doctoral Dissertations

Cross contamination during food processing represents a risk for public health and financial burden. Surface modification of food contact materials to render them antimicrobial can be effective against such risk. The objective of the present work was to develop antimicrobial coatings with the potential to be applied in a variety of food contact materials. The polymer coatings developed became antimicrobial by incorporation of a type of chlorinated compounds called N-halamines, capable of regenerating their antimicrobial activity. Two layer-by-layer (LbL) assembly surface modification procedures were followed. In the first procedure, bilayers of branched polyethyleneimine (PEI) and poly(acrylic acid) (PAA) were applied …