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2014

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Genetic And Biochemical Characterization Of The Roles Of Two Putative Purine Transporters In The Infectious Cycle Of Borrelia Burgdorferi, Sunny Jain Jan 2014

Genetic And Biochemical Characterization Of The Roles Of Two Putative Purine Transporters In The Infectious Cycle Of Borrelia Burgdorferi, Sunny Jain

Electronic Theses and Dissertations

Lyme disease, the most common tick borne disease in United States, is caused by the bacterial pathogen Borrelia burgdorferi. In nature, B. burgdorferi exists in an enzootic infectious cycle between an arthropod vector and mammalian hosts. Identification and characterization of the genes essential for B. burgdorferi survival throughout its infectious cycle is an important step toward understanding the molecular mechanisms involved in B. burgdorferi pathogenesis. B. burgdorferi contains a small genome, which lacks the genes encoding for the enzymes required for de novo synthesis of amino acids, fatty acids and nucleic acid precursors. Therefore, the spirochete is dependent upon the …


Unintended Outcomes Of Farmers' Adaptation To Climate Variability: Deforestation And Conservation In Calakmul And Maya Biosphere Reserves, Claudia Rodriguez-Solorzano Jan 2014

Unintended Outcomes Of Farmers' Adaptation To Climate Variability: Deforestation And Conservation In Calakmul And Maya Biosphere Reserves, Claudia Rodriguez-Solorzano

Dartmouth Scholarship

Minimizing the impact of climate change on farmer livelihoods is crucial, but adaptation efforts may have unintended consequences for ecosystems, with potential impacts on farmers’ welfare. Unintended outcomes of climate adaptation strategies have been widely discussed, however, empirical exploration has been neglected. Grounded in scholarship on climate adaptation, environmental governance, social–ecological systems, and land-use change, this paper studies whether farmers’ climate adaptation contributes to deforestation or forest conservation. The paper draws on interviews with 353 farmers from 46 communities in Calakmul Biosphere Reserve in Mexico and Maya Biosphere Reserve in Guatemala. Farmers in the area of study have implemented adaptation …


Serum C-X-C Motif Chemokine 13 Is Elevated In Early And Established Rheumatoid Arthritis And Correlates With Rheumatoid Factor Levels, Jonathan D. Jones, B. Jonell Hamilton, Gregory J. Challener, Artur J. De Brum-Fernandes Jan 2014

Serum C-X-C Motif Chemokine 13 Is Elevated In Early And Established Rheumatoid Arthritis And Correlates With Rheumatoid Factor Levels, Jonathan D. Jones, B. Jonell Hamilton, Gregory J. Challener, Artur J. De Brum-Fernandes

Dartmouth Scholarship

We hypothesized that serum levels of C-X-C motif chemokine 13 (CXCL13), a B-cell chemokine, would delineate a subset of rheumatoid arthritis (RA) patients characterized by increased humoral immunity.


Howard Elman's Farewell, Ernest Hebert Jan 2014

Howard Elman's Farewell, Ernest Hebert

Dartmouth Scholarship

Part Falstaff, part King Lear, but all American, Howard Elman was a fifty-something workingman when he burst onto the literary scene in The Dogs of March, the first novel of the Darby Chronicles. Now in this, its seventh installment, the Darby constable is an eighty-something widower who wants to do "a great thing" before he motors off into the sunset.

Maybe Howard achieves this goal, but he manages it in strange, wonderful, and dangerous ways. On his quest he's aided, abetted, hindered, and befuddled by his middle-aged children, his hundred-year-old hermit friend Cooty Patterson, a voice in his head, and …


Let-7 Microrna-Binding-Site Polymorphism In The 3′Utr Of Kras And Colorectal Cancer Outcome: A Systematic Review And Meta-Analysis, Scott M. Langevin, Brock C. Christensen Jan 2014

Let-7 Microrna-Binding-Site Polymorphism In The 3′Utr Of Kras And Colorectal Cancer Outcome: A Systematic Review And Meta-Analysis, Scott M. Langevin, Brock C. Christensen

Dartmouth Scholarship

There is a small but growing body of literature regarding the predictive utility of a Let-7 microRNA-binding-site polymorphism in the 30 -untranslated region (UTR) of KRAS (KRAS-LCS6) for colorectal cancer outcome, although the results are conflicting. We performed a review and meta-analysis in an attempt to better clarify this relationship. A PubMed search was conducted to identify all studies reporting on KRAS let-7 microRNA-binding site polymorphism (LCS6; rs61764370) and colorectal cancer outcome. Hazard ratios (HR) and corresponding 95% confidence intervals (CI) were extracted or estimated from each manuscript. Log HRs and log CIs were combined across studies using the inverse-variance …


For The Birds: Wind Energy, Dead Eagles, And Unwelcome Surprises, Sam Panarella Jan 2014

For The Birds: Wind Energy, Dead Eagles, And Unwelcome Surprises, Sam Panarella

Faculty Law Review Articles

Wind turbines kill birds. A lot of birds. You would be hard pressed to find someone who is happy with that fact, including anyone in the wind energy development community. But until and unless there are technological advances in wind turbine design that eliminate their deadly impact on birds, it is something we must accept. Of course, acceptance does not and should not mean issuing a blank check to wind energy developers to wantonly injure birds. To do so would violate both the spirit and letter of a host of environmental laws that have at their core a stubborn insistence …


Bipolar Nanosecond Electric Pulses Are Less Efficient At Electropermeabilization And Killing Cells Than Monopolar Pulses, Bennett L. Ibey, Olga N. Pakhomova, Caleb C. Roth, Shu Xiao, Karl Schoenbach, Andrei G. Pakhomov Jan 2014

Bipolar Nanosecond Electric Pulses Are Less Efficient At Electropermeabilization And Killing Cells Than Monopolar Pulses, Bennett L. Ibey, Olga N. Pakhomova, Caleb C. Roth, Shu Xiao, Karl Schoenbach, Andrei G. Pakhomov

Bioelectrics Publications

Multiple studies have shown that bipolar (BP) electric pulses in the microsecond range are more effective at permeabilizing cells while maintaining similar cell survival rates as compared to monopolar (MP) pulse equivalents. In this paper, we investigated whether the same advantage existed for BP nanosecond-pulsed electric fields (nsPEF) as compared to MP nsPEF. To study permeabilization effectiveness, MP or BP pulses were delivered to single Chinese hamster ovary (CHO) cells and the response of three dyes, Calcium Green-1, propidium iodide (PI), and FM1-43, was measured by confocal microscopy. Results show that BP pulses were less effective at increasing intracellular calcium …


Old Earth Theology: A Factor That Explains Inconsistent Belief Of Inerrancy Among Florida Southern Baptists, David A. Mcgee Jan 2014

Old Earth Theology: A Factor That Explains Inconsistent Belief Of Inerrancy Among Florida Southern Baptists, David A. Mcgee

Faculty Publications and Presentations

A major shift in thinking seems to be occurring in contemporary evangelical thinking. Southern Baptists overwhelmingly rejected the views of twentienth-century liberal Southern Baptist professors in favor of a literal translation of Genesis. Now, however, this debate may not be so one-sided among Southern Baptists. Within the current evangelical community there is a belief that the age of the earth has no bearing upon the doctrine of inerrancy. A study was conducted in 2013 that reveals belief in the age of the earth is one factor that contributes to the degree to which the doctrine of inerrancy is affirmed. The …


Novice Science Teachers' Thinking About The Purpose Of Teachers' Questions, Gwyndolyn Crittenden Jan 2014

Novice Science Teachers' Thinking About The Purpose Of Teachers' Questions, Gwyndolyn Crittenden

Electronic Theses and Dissertations

Effective teacher questioning during whole group instruction remains an important pedagogy in science education, especially the importance of helping novice teachers to guide student thinking using effective questions. This study examined how novice secondary science teachers’ understand the relationship between student thinking and teacher questioning. The sample was seven novice secondary science teachers’ enrolled in the University of Central Florida’s job embedded Resident Teacher Professional Preparation Program (RTP3 ). All participants received instruction and guided practice with the use of questions to elicit, probe, and challenge student ideas in the secondary science pedagogy class. Participants completed a questionnaire describing their …


The Influence Of A Career Planning Stem Explorations Course On Vocational Maturity, Career Decidedness And Career Thoughts For Undergraduate Students, Diandra Prescod Jan 2014

The Influence Of A Career Planning Stem Explorations Course On Vocational Maturity, Career Decidedness And Career Thoughts For Undergraduate Students, Diandra Prescod

Electronic Theses and Dissertations

According to the National Academy of Sciences (NAS), innovation that accompanies careers in science, technology engineering, and math (STEM) create a driving force in the economy and the creation of jobs, yet many positions remain open due to the lack of qualified individuals to fill them (NAS, 2011). Continuing research and innovation proves to be important, yet not enough students graduate with STEM degrees and enter into STEM careers. Career planning courses for undergraduate students increase student confidence about their abilities to make career decisions (Grier-Reed & Skaar, 2010: Scott & Ciani 2008). Vocational maturity and career decision making skills …


Validation Of A Novel Hypothesis Of Generating Foam Cells By Its Use To Study Reverse Cholesterol Transport, Bhaswati Sengupta Jan 2014

Validation Of A Novel Hypothesis Of Generating Foam Cells By Its Use To Study Reverse Cholesterol Transport, Bhaswati Sengupta

Electronic Theses and Dissertations

Generation of foam cells, an essential step for reverse cholesterol transport (RCT) studies, uses the technique of receptor dependent macrophage loading with radiolabeled acetylated Low Density Lipoprotein (Ac-LDL). In this study, we used the ability of a biologically relevant detergent molecule, Lysophosphatidylcholine (Lyso PtdCho), to form mixed micelles with cholesterol or cholesteryl ester (CE) to generate macrophage foam cells. Fluorescent or radiolabelled cholesterol / Lyso PtdCho mixed micelles were prepared and incubated with RAW 264.7 or mouse peritoneal macrophages. Results showed that such micelles were quite stable at 4°C and retained the solubilized cholesterol during one month storage. Macrophages incubated …


A Time-Course Analysis Of Behavioral Plasticity And Differential Gene Expression Patterns In Response To Density In Schistocerca Americana (Orthoptera: Acrididae), Steven Gotham Jan 2014

A Time-Course Analysis Of Behavioral Plasticity And Differential Gene Expression Patterns In Response To Density In Schistocerca Americana (Orthoptera: Acrididae), Steven Gotham

Electronic Theses and Dissertations

Phenotypic plasticity is the ability of the genotype to express alternative phenotypes in response to different environmental conditions and this is considered to be an adaptation in which a species can survive and persist in a rapidly changing environment. Some grasshoppers and locusts are capable of expressing an extreme form of density-dependent phenotypic plasticity, known as locust phase polyphenism. At low population density, the individuals typically have a cryptic coloration as nymphs, are less active, and only seek out conspecifics for reproductive purposes. At high density, however, they develop a drastically different phenotype in which they have a conspicuous coloration, …


Action Potentials As Indicators Of Metabolic Perturbations For Temporal Proteomic Analysis, Aditya Reddy Kolli Jan 2014

Action Potentials As Indicators Of Metabolic Perturbations For Temporal Proteomic Analysis, Aditya Reddy Kolli

Electronic Theses and Dissertations

The single largest cause of compound attrition during drug development is due to inadequate tools capable of predicting and identifying protein interactions. Several tools have been developed to explore how a compound interferes with specific pathways. However, these tools lack the potential to chronically monitor the time dependent temporal changes in complex biochemical networks, thus limiting our ability to identify possible secondary signaling pathways that could lead to potential toxicity. To overcome this, we have developed an in silico neuronal-metabolic model by coupling the membrane electrical activity to intracellular biochemical pathways that would enable us to perform non-invasive temporal proteomics. …


Multifunctional And Responsive Polyelectrolyte Nanostructures, Astha Malhotra Jan 2014

Multifunctional And Responsive Polyelectrolyte Nanostructures, Astha Malhotra

Electronic Theses and Dissertations

A polyelectrolyte complex is formed by mixing two oppositely charged polyelectrolytes in a solution. The electrostatic interactions between partially charged polymeric chains lead to the formation of a stable complex while avoiding the use of covalent cross linkers. Since complex formation can improve the stability of polyelectrolyte and metal ions in polyelectrolyte can provide various functionalities, PECs incorporated with metal ions are promising candidates for manufacturing stable and multifunctional structures. While the coordination of metal ions and polyelectrolytes has been extensively investigated in solutions and multilayer films, to our knowledge, no research has been performed to study the effect of …


Chemical Differentiation Of Human Osseous, Non-Human Osseous, And Non-Osseous Materials Using Scanning Electron Microscopy - Energy Dispersive X-Ray Spectrometry (Sem/Edx) And Multivariate Statistical Analysis, Cayli Meizel-Lambert Jan 2014

Chemical Differentiation Of Human Osseous, Non-Human Osseous, And Non-Osseous Materials Using Scanning Electron Microscopy - Energy Dispersive X-Ray Spectrometry (Sem/Edx) And Multivariate Statistical Analysis, Cayli Meizel-Lambert

Electronic Theses and Dissertations

Identification of osseous materials is generally established on gross anatomical factors; however, highly fragmented or taphonomically altered materials are often problematic and alternative methods, such as biological, histological, or chemical analysis, must be utilized. Recently, chemical methods have been proposed to sort unknown materials according to their Ca/P ratios. Ubelaker and colleagues (2002) proposed using SEM/EDX to achieve this distinction and Christensen and colleagues (2012) have validated X-ray Fluorescence Spectrometry (XRF) for this application. An alternative method of analysis involves performing principal component analysis (PCA) on element spectra to classify unknown materials based on their trace element composition. Zimmerman (2013) …


Diet At Medieval Alytus, Lithuania: Stable Carbon And Nitrogen Isotope Analysis Of Bone And Dentin Collagen, Katie Whitmore Jan 2014

Diet At Medieval Alytus, Lithuania: Stable Carbon And Nitrogen Isotope Analysis Of Bone And Dentin Collagen, Katie Whitmore

Electronic Theses and Dissertations

The Baltic region was a vibrant center of power and economic prosperity in medieval Europe; Lithuania in particular. Until now, little stable isotopic analysis has been utilized to assess diet in this region during this time period. The aim of this study was to undertake a preliminary assessment of the composition of diet at late medieval Alytus (late 14th to early 18th centuries) from bone (N=35) and dentin (N=38) collagen samples. The stable carbon isotopic data suggest a diet primarily comprised of C3 plants such as barley, rye, wheat, and flax, and animals consuming C3 plants. The stable nitrogen isotopic …


Cerium Oxide Nanoparticles: Their Phosphatase Activity And Its Control, Atul Dhall Jan 2014

Cerium Oxide Nanoparticles: Their Phosphatase Activity And Its Control, Atul Dhall

Electronic Theses and Dissertations

Cerium oxide nanoparticles are established scavengers of reactive oxygen and nitrogen species. They have many potential biomedical applications that depend on their physicochemical properties and mode of preparation. Recent studies have found these nanoparticles possess phosphatase mimetic activity. Studying such catalytic activities will qualify their biomedical applications and render information on their bioavailability and potential toxicity. Two oxidation states of cerium exist in these nanoparticles (3+ or 4+). It is hypothesized that the oxidation state of cerium in the nanoparticles determines the amount of adsorbed water on the crystal lattices. This in turn governs their activity as phosphatases. Nanoparticles with …


The Influence Of Mesa Activities On Underrepresented Students Nsf Dr K-12 Proposal 1020019, C. Hailey, Chandra Austin Stallworth, Cameron Denson, Daniel L. Householder Jan 2014

The Influence Of Mesa Activities On Underrepresented Students Nsf Dr K-12 Proposal 1020019, C. Hailey, Chandra Austin Stallworth, Cameron Denson, Daniel L. Householder

Mechanical and Aerospace Engineering Faculty Publications

Mathematics, Engineering, Science Achievement (MESA) outreach programs are partnerships between K-12 schools and higher education in nine states. MESA efforts introduce integrated experiences in science, mathematics and engineering to K-12 students from groups that are traditionally underrepresented in the STEM disciplines. This exploratory study examined the influence of selected MESA activities on students' self-efficacy, their perceptions of engineering, and their interest in engineering and other STEM fields. Field trips, guest lecturers, design competitions, hands-on activities and student career and academic advisement were of specific interest in this survey. The project also investigated the relationship between student engagement in MESA and …


Design And Implementation Of Home Use Portable Smart Electronics, Liqiang Du Jan 2014

Design And Implementation Of Home Use Portable Smart Electronics, Liqiang Du

Dissertations, Master's Theses and Master's Reports - Open

The widespread of low cost embedded electronics makes it easier to implement the smart devices that can understand either the environment or the user behaviors. The main object of this project is to design and implement home use portable smart electronics, including the portable monitoring device for home and office security and the portable 3D mouse for convenient use. Both devices in this project use the MPU6050 which contains a 3 axis accelerometer and a 3 axis gyroscope to sense the inertial motion of the door or the human hands movement.

For the portable monitoring device for home and office …


Investigation Of Strategies To Promote Effective Teacher Professional Development Experiences In Earth Science, Carol A. Engelmann Jan 2014

Investigation Of Strategies To Promote Effective Teacher Professional Development Experiences In Earth Science, Carol A. Engelmann

Dissertations, Master's Theses and Master's Reports - Open

This dissertation serves as a call to geoscientists to share responsibility with K-12 educators for increasing Earth science literacy. When partnerships are created among K-12 educators and geoscientists, the synergy created can promote Earth science literacy in students, teachers, and the broader community. The research described here resulted in development of tools that can support effective professional development for teachers. One tool is used during the planning stages to structure a professional development program, another set of tools supports measurement of the effectiveness of a development program, and the third tool supports sustainability of professional development programs. The Michigan Teacher …


Integration Of Instrumentation And Processing Software Of A Laser Speckle Contrast Imaging System, Jacob James Carrick Jan 2014

Integration Of Instrumentation And Processing Software Of A Laser Speckle Contrast Imaging System, Jacob James Carrick

Dissertations, Master's Theses and Master's Reports - Open

Laser speckle contrast imaging (LSCI) has the potential to be a powerful tool in medicine, but more research in the field is required so it can be used properly. To help in the progression of Michigan Tech's research in the field, a graphical user interface (GUI) was designed in Matlab to control the instrumentation of the experiments as well as process the raw speckle images into contrast images while they are being acquired. The design of the system was successful and is currently being used by Michigan Tech's Biomedical Engineering department. This thesis describes the development of the LSCI GUI …


Remediation Of Tetracycline From Water Sources Using Vetiver Grass (Chrysopogon Zizanioides L. Nash) And Tetracycline-Tolerant Root-Associated Bacteria, Aparupa Sengupta Jan 2014

Remediation Of Tetracycline From Water Sources Using Vetiver Grass (Chrysopogon Zizanioides L. Nash) And Tetracycline-Tolerant Root-Associated Bacteria, Aparupa Sengupta

Dissertations, Master's Theses and Master's Reports - Open

Antibiotics are emerging contaminants worldwide. Due to insufficient policy regulations, public awareness, and the constant exposure of the environment to antibiotic sources has created a major environmental concern. Wastewater treatment plants (WWTP) are not equipped to filter-out these compounds before the discharge of the disinfected effluent into water sources (e.g., lakes and streams) and current available technologies are not equipped to remediate these compounds from environmental sources. Hence, the challenge remains to establish a biological system to remove these antibiotics from wastewater. An invitro hydroponic remediation system was developed using vetiver grass (Chrysopogon zizanioides L. Nash) to remediate tetracycline …


Mining And Verification Of Temporal Events With Applications In Computer Micro-Architecture Research, Hui Meen Nyew Jan 2014

Mining And Verification Of Temporal Events With Applications In Computer Micro-Architecture Research, Hui Meen Nyew

Dissertations, Master's Theses and Master's Reports - Open

Computer simulation programs are essential tools for scientists and engineers to understand a particular system of interest. As expected, the complexity of the software increases with the depth of the model used. In addition to the exigent demands of software engineering, verification of simulation programs is especially challenging because the models represented are complex and ridden with unknowns that will be discovered by developers in an iterative process. To manage such complexity, advanced verification techniques for continually matching the intended model to the implemented model are necessary. Therefore, the main goal of this research work is to design a useful …


A Theoretical Study Of Interaction Of Nanoparticles With Biomolecule, Chunhui Liu Jan 2014

A Theoretical Study Of Interaction Of Nanoparticles With Biomolecule, Chunhui Liu

Dissertations, Master's Theses and Master's Reports - Open

Many types of materials at nanoscale are currently being used in everyday life. The production and use of such products based on engineered nanomaterials have raised concerns of the possible risks and hazards associated with these nanomaterials. In order to evaluate and gain a better understanding of their effects on living organisms, we have performed first-principles quantum mechanical calculations and molecular dynamics simulations. Specifically, we will investigate the interaction of nanomaterials including semiconducting quantum dots and metallic nanoparticles with various biological molecules, such as dopamine, DNA nucleobases and lipid membranes.

Firstly, interactions of semiconducting CdSe/CdS quantum dots (QDs) with the …


Purification And Effectiveness Of Vaccines And Antiviral Compounds, Maria F. Gencoglu Jan 2014

Purification And Effectiveness Of Vaccines And Antiviral Compounds, Maria F. Gencoglu

Dissertations, Master's Theses and Master's Reports - Open

Viral infections account for over 13 million deaths per year. Antiviral drugs and vaccines are the most effective method to treat viral diseases. Antiviral compounds have revolutionized the treatment of AIDS, and reduced the mortality rate. However, this disease still causes a large number of deaths in developing countries that lack these types of drugs. Vaccination is the most effective method to treat viral disease; vaccines prevent around 2.5 million deaths per year. Vaccines are not able to offer full coverage due to high operational costs in the manufacturing processes. Although vaccines have saved millions of lives, conventional vaccines often …


Enzyme Optimization For Lignocellulose Hydrolysis Using Mechanistic Modeling, Adam S. Marlowe Jan 2014

Enzyme Optimization For Lignocellulose Hydrolysis Using Mechanistic Modeling, Adam S. Marlowe

Dissertations, Master's Theses and Master's Reports - Open

A novel mechanistic model for the saccharification of cellulose and hemicellulose is utilized to predict the products of hydrolysis over a range of enzyme loadings and times. The mechanistic model considers the morphology of the substrate and the kinetics of enzymes to optimize enzyme concentrations for the enzymatic hydrolysis of cellulose and hemicellulose simultaneously. Substrates are modeled based on their fraction of accessible sites, glucan content, xylan content, and degree of polymerizations. This enzyme optimization model takes into account the kinetics of six core enzymes for lignocellulose hydrolysis: endoglucanase I (EG1), cellobiohydrolase I (CBH1), cellobiohydrolase II (CBH2), and endo-xylanase (EX) …


Characterizing And Improving Production Of Fermentable Sugars And Co-Products From A Forest Product Industry Wastewater Stream, Jifei Liu Jan 2014

Characterizing And Improving Production Of Fermentable Sugars And Co-Products From A Forest Product Industry Wastewater Stream, Jifei Liu

Dissertations, Master's Theses and Master's Reports - Open

Hardboard processing wastewater was evaluated as a feedstock in a bio refinery co-located with the hardboard facility for the production of fuel grade ethanol. A thorough characterization was conducted on the wastewater and the composition changes of which during the process in the bio refinery were tracked. It was determined that the wastewater had a low solid content (1.4%), and hemicellulose was the main component in the solid, accounting for up to 70%. Acid pretreatment alone can hydrolyze the majority of the hemicellulose as well as oligomers, and over 50% of the monomer sugars generated were xylose. The percentage of …


New Microfluidic System To Increase Robustness Of Electrode Performance And Develop Point-Of-Care Hematocrit Device, Hwi Yong Lee Jan 2014

New Microfluidic System To Increase Robustness Of Electrode Performance And Develop Point-Of-Care Hematocrit Device, Hwi Yong Lee

Dissertations, Master's Theses and Master's Reports - Open

The present dissertation aimed to develop a new microfluidic system for a point-of-care hematocrit device. Stabilization of microfluidic systems via surfactant additives and integration of semipermeable SnakeSkin® membranes was investigated. Both methods stabilized the microfluidic systems by controlling electrolysis bubbles. Surfactant additives, Triton X-100 and SDS stabilized promoted faster bubble detachment at electrode surfaces by lowering surface tension and decreased gas bubble formation by increasing gas solubility. The SnakeSkin® membranes blocked bubbles from entering the microchannel and thus less disturbance to the electric field by bubbles occurred in the microchannel. Platinum electrode performance was improved by carbonizing electrode surface using …


Molecular Characterization Of Atmospheric Organic Matter In Biogenic Secondary Organic Aerosol, Ambient Aerosol And Clouds, Yunzhu Zhao Jan 2014

Molecular Characterization Of Atmospheric Organic Matter In Biogenic Secondary Organic Aerosol, Ambient Aerosol And Clouds, Yunzhu Zhao

Dissertations, Master's Theses and Master's Reports - Open

Atmospheric aerosol affects the Earth’s energy budget, reduces visibility and influences human health. The organic composition of aerosol is quite complex and continuously evolves through various atmospheric processes. To gain a deeper understanding of the molecular composition of atmospheric organic matter (AOM), chamber-generated biogenic secondary organic aerosol (SOA), ambient aerosol and cloud water samples were studied. Ultrahigh resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry was used to provide detailed molecular characterization of the atmospheric samples. Due to the extremely high mass resolution and mass accuracy, thousands of individual molecular formulas were identified in all of the samples studied. Multivariate …


Ionic Liquid Extraction Unveils Previously Occluded Humicbound Iron In Peat Porewater, Timothy J. Veverica Jan 2014

Ionic Liquid Extraction Unveils Previously Occluded Humicbound Iron In Peat Porewater, Timothy J. Veverica

Dissertations, Master's Theses and Master's Reports - Open

Extracellular iron reduction has been suggested as a candidate metabolic pathway that may explain a large proportion of carbon respiration in temperate peatlands. However, the o-phenanthroline colorimetric method commonly employed to quantitate iron and partition between redox species is known to be unreliable in the presence of humic and fulvic acids, both of which represent a considerable proportion of peatland dissolved organic matter. We propose ionic liquid extraction as a more accurate iron quantitation and redox speciation method in humic-rich peat porewater. We evaluated both o-phenanthroline and ionic liquid extraction in four distinct peatland systems spanning a gradient of physico-chemical …