Digital Commons Network^™

Strategies To Improve The Performance Of Antioxidants In Oil-In-Water Emulsions, Atikorn Panya

Open Access Dissertations

Due to the limited number of approved antioxidants for food applications, several alternative strategies to improve antioxidant performance have been developed by focusing on synergistic antioxidant interactions. Susceptibility to lipid oxidation in food systems is the result of the summation of antioxidative and prooxidative mechanisms. Understanding the sometimes paradoxical behavior of antioxidants and prooxidants is a vital key to design synergistic antioxidant systems suitable for particular foods. This research focused on 3 main strategies to improve the performance of antioxidant activity in oil-in-water emulsions.

The first part of this research has been focused on inhibition of lipid oxidation by a …

Fabrication, Characterization And Utilization Of Filled Hydrogel Particles As Food Grade Delivery Systems, Alison M. Matalanis

Open Access Dissertations

Filled hydrogel particles consisting of emulsified oil droplets encapsulated within a hydrogel matrix were fabricated based on the phase separation of proteins and polysaccharides through aggregative and segregative mechanisms. A 3% (wt/wt) pectin and 3% (wt/wt) caseinate mixture at pH 7 separated into an upper pectin-rich phase and a lower casein-rich phase. Casein-coated lipid droplets added to this mixture partitioned into the lower casein-rich phase. When shear was applied, an oil-in-water-in-water (O/W1/W2) emulsion consisting of oil droplets (O) contained within a casein-rich dispersed phase (W1) suspended in a pectin-rich continuous phase (W2) was formed. Acidification from pH 7 to 5 …

Biological Control Of The Ambermarked Birch Leafminer (Profenusa Thomsoni) In Alaska, Anna L. Soper

Open Access Dissertations

The ambermarked birch leafminer (AMBLM) (Profenusa thomsoni) is an invasive leafminer native to the Palearctic from the United Kingdom to Turkey to Japan. It was introduced to the eastern United States in 1921 and has since spread to the mid-western U.S. states and Canadian provinces. This leafminer was introduced to Alaska in 1996, where it has since spread over 140,000 acres, from Haines to Fairbanks. The most severe damage is found throughout the Anchorage bowl, which extends south to Girdwood and North to Wasilla. The damage caused by P. thomsoni can be severe, defoliating entire trees. In 2006, it was …

Adsorption Column Studies To Predict The Flow Of Nutrients Through Heterogenous Porous Media Under Equilibrium And Isothermal Conditions, Vijai B. Pandey

Open Access Dissertations

Because of the endangerment of life of the human beings due to the environmental pollution, a serious study of the pollution of the environment is most vital. Because of increasing surface water pollution there is great hazard of ground water pollution. About half the United States of America derives drinking water from aquifers and much of the projected demand is expected to be met from subsurface sources. Therefore, a study was needed to determine the process of ground water contamination due to nutrients, especially Nitrogen, its degree and Length and Time of Travel and factors inhibiting its flow through soil. …

Minor Components And Their Roles On Lipid Oxidation In Bulk Oil That Contains Association Colloids, Bingcan Chen

Open Access Dissertations

The combination of water and surface active compounds found naturally in commercially refined vegetable oils have been postulated to form physical structures known as association colloids. This research studied the ability of 1,2-dioleoyl-sn-glycerol-3-phosphocholine (DOPC) and water to form physical structures in stripped soybean oil. Interfacial tension and fluorescence spectrometry results showed the critical micelle concentration (CMC) of DOPC in stripped soybean oil was 650 and 950 microM, respectively. Light scattering attenuation results indicated that the structure formed by DOPC was reverse micelles. The physical properties of DOPC reverse micelles were determined using small-angle X-ray scattering (SAXS) and fluorescence probes. These …

Management Of Switchgrass For The Production Of Biofuel, Leryn Elise Gorlitsky

Open Access Dissertations

Switchgrass (Panicum virgatum L.) is a warm-season perennial being considered as a biofuel to meet energy challenges. In Massachusetts, a small state where the price of land is expensive, farmers want to determine if switchgrass can produce sufficient yields for consecutive years to warrant its production. The objective of this study was to determine what harvest management practices affect the vigor and health of switchgrass and which varieties produce the best yields for biofuel production.

Four experiments were conducted from 2009-2012. Twelve varieties were tested to determine their viability in the Massachusetts climate. Five were chosen for further chemical analysis. …

Target Recognition And Competitive Synaptogenesis In The Drosophila Giant Fiber System, Jason Joseph Hill

Open Access Dissertations

The development of complex neural networks relies on a careful balance of environmental cues to guide and shape both ends of the eventual connection. However, the correct wiring of circuits whose components share molecular profiles depends on a more elaborate phenomenon, competition. Despite being highly studied, there is still a lack of understanding as to the mechanism that allows molecularly identical cells to form exclusive connections with their targets. To address this complex question, we turned to a simple circuit within the genetically tractable fly. Responsible for the escape reflex, the Giant Fiber System is comprised of bilaterally symmetrical axons …

The Influence Of Free-Living Activity And Inactivity On Health Outcomes And Responsiveness To Exercise Training, Sarah Kozey Keadle

Open Access Dissertations

On average, starting an exercise training program decreases one’s risk for chronic disease. However, there is remarkable individual variability in physiologic responses to exercise training. The activity and inactivity during the remaining 95% of the day (when the individual is not training) is rarely considered. The overall objective of this dissertation was to apply validated sedentary behavior (SB) and physical activity (PA) measurement techniques during an exercise training study to determine if time spent in SB and PA outside of training influences the physiological response to training. Twenty subjects participated in a pilot study to determine the feasibility of reducing …

Influence Of Phosphate On The Adsorption/Desorption Of Bovine Serum Albumin On Nano And Bulk Oxide Particles, Lei Song

Open Access Dissertations

This work consists of four sections: 1) the adsorption behavior of bovine serum albumin (BSA) by three types of oxide nanoparticles (NPs), TiO2 (50 ± 5 nm), SiO2 (30 ± 5nm), and Al2O3 (150 ± 5 nm for α type and 60 ± 5 nm for γ type) in deionized water; 2) phosphate adsorption on these oxide NPs and bulkparticles (BPs); 3) influence of phosphate ions on BSA adsorption; and 4) BSA desorption from oxide NPs in phosphate solution. BPs were also used for comparison with NPs. For BSA adsorption in deionized water, the adsorption maxima on oxide particles are …

Distributions Of Large Mammal Assemblages In Thailand With A Focus On Dhole (Cuon Alpinus) Conservation, Kate Elizabeth Jenks

Open Access Dissertations

Biodiversity monitoring and predictions of species occurrence are essential to develop outcome-oriented conservation management plans for endangered species and assess their success over time. To assess distribution and patterns of habitat use of large mammal assemblages in Thailand, with a focus on the endangered dhole (Cuon alpinus), I first implemented a long-term camera-trapping project carried out with park rangers from October 2003 through October 2007 in Khao Yai National Park. This project was extremely successful and may serve as a regional model for wildlife conservation. I found significantly lower relative abundance indices for carnivore species, and collectively for all mammals …

A Comprehensive Model Of Human Neuromuscular Function During Repeated Isometric Contractions: Predicting The Effect Of Age On Fatigue, Damien Mark Callahan

Open Access Dissertations

Repeated or prolonged activation of skeletal muscle results in an acute decline in the muscle's ability to produce force, which is typically referred to as fatigue. Muscle fatigue is likely related to the by-products of cellular metabolism, alterations in neural activation and diminished membrane excitability that have been shown to accompany repeated contractions. However, the complicated etiology of the fatigue process makes it difficult to understand the relative influence of these physiological responses. Computational modeling of the skeletal muscle response to repeated activation is an appealing means of gaining insight into the mechanisms of muscle fatigue. A reasonably comprehensive model …

Adaptations To Stride Patterns And Head Movements During Walking In Persons With And Without Multiple Sclerosis, Jebb Grigory Remelius

Open Access Dissertations

Many people with multiple sclerosis (MS) have difficulty with walking, which can decrease their sense of mobility. Gait stability was investigated by studying stride parameters and head movements at preferred and fixed speeds in those with MS. First, walking gait data were recorded at preferred and fixed walking speeds from 19 individuals with MS and 19 controls. Traditional gait parameters were compared, as was swing foot to center of mass (CoM) timing at mid-swing. Second, walking gait data in healthy young adults (n=20) were recorded at preferred speed and while stepping over an obstacle. Study 2 developed novel swing definitions, …

Cellular And Molecular Changes Following Skeletal Muscle Damage: A Role For Nf-Kb And Muscle Resident Pericytes, Robert H. Hyldahl

Open Access Dissertations

Skeletal muscle is dynamic and actively regenerates following damage or altered functional demand. Regeneration is essential for the maintenance of muscle mass and, when dysregulated as a result of disease or aging, can lead to losses in functional capacity and increased mortality. Limited data exist on the molecular mechanisms that govern skeletal muscle regeneration in humans. Therefore, the overall objective of this dissertation was to characterize early molecular alterations in human skeletal muscle to strenuous exercise known to induce a muscle regenerative response. Thirty-five subjects completed 100 eccentric (muscle lengthening) contractions (EC) of the knee extensors with one leg and …

Components Of A Protein Machine: Allosteric Domain Assembly And A Disordered C-Terminus Enable The Chaperone Functions Of Hsp70, Robert G. Smock

Open Access Dissertations

Hsp70 molecular chaperones protect proteins from aggregation, assist in their native structure formation, and regulate stress responses in the cell. A mechanistic understanding of Hsp70 function will be necessary to explain its physiological roles and guide the therapeutic modulation of various disease states. To this end, several fundamental features of the Hsp70 structure-function relationship are investigated. The central component of Hsp70 chaperone function is its capacity for allosteric signaling between structural domains and tunable binding of misfolded protein substrates. In order to identify a cooperative network of sites that mediates interdomain allostery within Hsp70, a mutational correlation analysis is performed …

Phylogenics And Patterns Of Molecular Evolution In Amoebozoa, Daniel J.G. Lahr

Open Access Dissertations

My dissertation explores several aspects of the relationship between morphological and molecular evolution in amoeboid lineages:

Chapter 1 - General Introduction: This chapter provides an overview of the most pressing issues in Amoebozoa phylogeny that are dealt with in the remainder of the thesis

Chapter 2 - Reducing the impact of PCR-mediated recombination in molecular evolution and environmental studies using a new generation high fidelity DNA polymerase: This chapter addresses the methodological difficulty in the study of large gene families, the generation of artifactual sequences by recombination during PCR.

Chapter 3 - Evolution of the actin gene family in testate …

The Conservation Value Of Residential Landscapes For Native Bird Communities: Patterns, Processes, And Management Implications, Susannah Beth Lerman

Open Access Dissertations

Urbanization, as it transforms natural biotic systems into human-dominated landscapes, is recognized as one of the greatest threats to biodiversity throughout the world. Furthermore, urban dwellers are becoming increasingly disconnected with the natural world. Here I investigate whether residential landscape designs that mimic the natural environment can provide habitat for native birds. First I uncover some of the patterns of bird distribution in residential yards by incorporating habitat features, urbanization measurements and socioeconomic factors with bird monitoring data into a multivariate analysis. The results indicate that native birds associate with neighborhoods with native plants and shrubs, neighborhoods closer to desert …

Investigation Of A Sulfur-Utilizing Perchlorate-Reducing Bacterial Consortium, Teresa Anne Conneely

Open Access Dissertations

We present research investigating how, with in depth knowledge of the community, microbial communities may be harnessed for bioremediation of hazardous water contaminants. We focused on the bacterial reduction of perchlorate, a common water contaminant. For this we studied the structure and capabilities of a novel sulfur-utilizing, perchlorate-reducing bacterial (SUPeRB) consortium. Initially, we characterized the minimal consortium that retained functional capabilities, using 16S rRNA and functional gene analysis. A diverse functional consortium dominated by Beta-Proteobacteria of the family Rhodocyclaceae and sulfur-oxidizing Epsilon-Proteobacteria was found. We also examined the optimal growth conditions under which perchlorate degradation occurred and uncovered the upper …

Effects Of Free Fatty Acids, Mono- And Diacylglycerols On Oxidative Stability Of Soybean Oil-In-Water Emulsions, Thaddao Waraho

Open Access Dissertations

Even though edible oils undergo refining processes to remove undesirable components, commercial oils still contain small amounts of minor components that can contribute to either prooxidant and antioxidant pathways which ultimately affect the quality of the oils. The objective of this research was to determine the role of free fatty acids and mono- and diacylglycerols on the oxidative stability of oil-in-water emulsions.

Free fatty acids acted as a strong prooxidants in stripped soybean oil-in-water emulsions. Concentrations as low as 0.1% of the lipid accelerated lipid oxidation rate by both shortening the lag phase of lipid hydroperoxide and hexanal formation. The …

Armillaria In Massachusetts Forests: Ecology, Species Distribution, And Population Structure, With An Emphasis On Mixed Oak Forests, Nicholas Justin Brazee

Open Access Dissertations

The ecology, species distribution, and population structure of Armillaria was investigated in the forests of Massachusetts. From 64 plots at 16 sites, 640 isolates of Armillaria were collected from six forest types (northern hardwoods, mixed oak, pitch pine, white pine, white pine/mixed oak, and eastern hemlock). Armillaria gallica proved to be the most abundant species, making up 316/640 (52%) of all isolations. This was followed by A. solidipes (219/640; 34%), A. mellea (46/640; 7%), A. calvescens (36/640; 6%), A. gemina (16/640; 3%), and A. sinapina (7/640; 1%). Armillaria gallica was routinely encountered causing significant decay of the lower bole on …

Metformin And/Or Exercise Training Affect Metabolic Health In Men And Women With Prediabetes, Steven K. Malin

Open Access Dissertations

Prediabetes is defined by elevated blood glucose concentrations not high enough to meet criteria for type 2 diabetes. Exercise or metformin, a common “anti-diabetes” medication, may attenuate the progression from prediabetes to type 2 diabetes by improving insulin sensitivity and cardio-metabolic health. Because each treatment has its primary action in different tissues, combining exercise (muscle) with metformin (liver) may further enhance insulin sensitivity and cardio-metabolic health. Purpose: To determine the efficacy of combining exercise training with metformin on insulin sensitivity and cardio-metabolic health in men and women with prediabetes. We hypothesized that the combined treatment would improve insulin sensitivity and …

Mitochondrial Dna Polymerase Ib: Functional Characterization Of A Putative Drug Target For African Sleeping Sickness, David F. Bruhn

Open Access Dissertations

Trypanosoma brucei and related parasites are causative agents of severe diseases that affect global health and economy. T. brucei is responsible for sleeping sickness in humans (African trypanosomiasis) and a wasting disease in livestock. More than 100 years after T. brucei was identified as the etiological agent for sleeping sickness, available treatments remain inadequate, complicated by toxicity, lengthy and expensive administration regiments, and drug-resistance. There is clear need for the development of a new antitrypanosomal drugs. Due to the unique evolutionary position of these early diverging eukaryotes, trypanosomes posses a number of biological properties unparalleled in other organisms, including humans, …

The Role Of The Suprmam1 Locus In Responses To Ionizing Radiation And Susceptibility To Mammary Tumors, Nicholas B. Griner

Open Access Dissertations

Loss of p53 function can lead to a variety of cancers, including breast cancer. Mice heterozygous for the p53 gene (designated Trp53+/-) develop spontaneous mammary tumors, but this depends on the strain background and has been linked to a locus on chromosome 7 (designated SuprMam1). Mammary tumors are common in BALB/c-Trp53+/-females, but are rare in C57BL/6-Trp53+/- mice. Prevalence of genomic instability appears to contribute to the phenotype as loss of heterozygosity (LOH) is significantly more common among tumors arising in BALB/c-Trp53+/- mice compared to C57BL/6J-Trp53+/- mice. This increased LOH in BALB/c-Trp53+/- tumors was shown to be due to recombination events. …

Developing An Efficient Cover Cropping System For Maximum Nitrogen Recovery In Massachusetts, Ali Farsad

Open Access Dissertations

Time of planting plays a critical role in nitrogen (N) uptake by rye cover crop (CC). Even a few days of delay in planting can severely decrease CC performance. Evaluating the amount of N accumulation related to time of planting is critical to the farmer who has to optimize the winter rye planting date based on completion of corn harvest, suitable weather conditions and time availability for fall manure application. Winter rye cover crop was planted at 6 planting dates in fall from mid August to early October at weekly intervals from 2004 to 2009.

The results suggest that delay …

Bacterial Toxicity Of Oxide Nanoparticles And Their Effects On Bacterial Surface Biomolecules, Wei Jiang

Open Access Dissertations

Toxicity of nano-scaled Al2O3, SiO2, TiO2 and ZnO to bacteria (Bacillus subtilis, Escherichia coli and Pseudomonas fluorescens) was examined and compared to that of their respective bulk (micro-scaled) counterparts. All nanoparticles (NPs) but TiO2 showed higher toxicity than their bulk counterparts. Toxicity of released metal ions was differentiated from that of the oxide particles. ZnO was the most toxic among the three NPs, causing 100% mortality to the three tested bacteria. TEM images showed attachment of NPs to the bacteria, suggesting that the toxicity was affected by bacterial attachment.

The effects of oxide NPs on bacteria cells and bacterial surface …

Movin' & Groovin' Salamanders: Conservation Implications Of Large Scales And Quirky Sex, Noah D. Charney

Open Access Dissertations

Mole salamanders (Ambystoma) and woodfrogs (Lithobates sylvaticus) are abundant in New England and depend on ephemeral wetlands for breeding. Their aquatic habitats have been well studied and are protected by several local and regional regulations. State endangered species laws also protect mabled salamanders (A. opacum), Jefferson salamanders (A. jeffersonianum), and blue-spotted salamanders (A. laterale). However, these amphbibians spend most of their adult lives in terrestrial habitats that remain poorly protected and elusive to researchers.

In chapter 1, I developed a novel technique using passive integrated transponders for tracking small animals. I used this technique to track marbled salamanders walking up …

The Roles Of Notch1 And Pkc-Θ In Immune Mediated Bone Marrow Failure, Justine E. Roderick

Open Access Dissertations

We sought to evaluate the individual contributions of Notch1 and PKC-ζ to disease progression in a mouse model of immune-mediated bone marrow failure and to define a mechanism for their potential cellular cooperation. We transferred parental bulk splenocytes into F1-hybrid recipients to induce a robust immune-mediated bone marrow failure (BMF) that we could partially rescue by administering a pharmacological inhibitor of Notch activation. Transferring splenocytes from PKC--ζ-/- animals did not induce disease, and treating animals with a pharmacological inhibitor of PKC-ζ also provided full protection from disease. We found that inhibiting Notch1 resulted in PKC-ζ down-regulation, and blocking PKC-ζ reduced …

Consequence Of Functioning At The End Range Of Joint Motion: Implications On Anterior Knee Pain, Pedro A. Rodrigues

Open Access Dissertations

“Excessive” and/or “delayed” subtalar joint (STJ) pronation has been linked to overuse injuries because of its influence on tibial internal rotation (TIR). The transfer of STJ pronation to TIR occurs via the talocrual joint, believed to have limited transverse plane motion. However, studies have shown the talocrural joint to have more transverse plane motion than once believed, therefore it is feasible that the STJ will only influence the motion of the tibia once this motion has been exhausted.

Currently, studies evaluating this relationship have focused on peak joint angles and excursion without reference to the amount of motion available at …

Novel Systems For The Functional Characterization Of Genes Related To Paclitaxel Metabolism In Taxus Cell Cultures, Khamkeo Vongpaseuth

Open Access Dissertations

Human society has benefited greatly from plant secondary metabolites, often utilizing a variety of compounds as dyes, food additives, and drugs. In particular, pharmaceutical development has benefited greatly from plant secondary metabolites. One example of this utility is paclitaxel, a highly substituted diterpene approved in the treatment of breast cancer, ovarian cancer, non-small cell lung cancer, and the AIDSrelated Kaposi’s sarcoma. Demand of paclitaxel is likely to increase, due to the current examination of paclitaxel in numerous clinical trials against a variety of other cancers.

Taxus cell culture represents a production source of paclitaxel to meet future demand. However, paclitaxel …

Optimal Control Of Human Running, Ross Herbert Miller

Open Access Dissertations

Humans generally use two modes of locomotion as adults. At slow speeds we walk, and at fast speeds we run. To perform either gait, we use our muscles. The central questions in this dissertation were: (1) Why do humans run the way they do, and (2) How do the mechanical properties of muscle influence running performance? Optimal control simulations of running were generated using a bipedal forward dynamics model of the human musculoskeletal system. Simulations of running and sprinting were posed as two-point boundary value problems where the muscle excitation signals were optimized to maximize an optimality criterion. In the …

Adaptations To Running While Footwear Cushioning And Surface Are Manipulated, Trampas M. Tenbroek

Open Access Dissertations

Minimal footwear sales have encountered rapid growth over the last several years. Minimal footwear are often constructed with thin basic uppers and thin, flexible midsoles. It is likely that running in minimal footwear will require adaptation and adjustments as the amount of cushioning and the geometry of the foot/ground interface will be substantially different than what many are accustomed to. This research investigated the effect footwear cushioning amount and the running surface had on running patterns. Study 1 (Chapter IV) utilized two different running footwear conditions and two different cushioned treadmill conditions, as well as a barefoot condition, to investigate …