Digital Commons Network^™

Rickettsia Felis In Ctenocephalides Felis From Guatemala And Costa Rica, Adriana Troyo, Danilo Alvarez, Lizeth Taylor, Gabriela Abdalla, Olger Calderon-Arguedas, Maria L. Zambrano, Gregory A. Dasch, Kim A. Lindblade, Laya Hun, Marina Eremeeva, Alejandra Estevez

Environmental Health Sciences: Faculty Publications

Rickettsia felis is an emerging human pathogen associated primarily with the cat flea Ctenocephalides felis. In this study, we investigated the presence of Rickettsia felis in C. felis from Guatemala and Costa Rica. Ctenocephalides felis were collected directly from dogs and cats, and analyzed by polymerase chain reaction for Rickettsia-specific fragments of 17-kDa protein, OmpA, and citrate synthase genes. Rickettsia DNA was detected in 64% (55 of 86) and 58% (47 of 81) of flea pools in Guatemala and Costa Rica, respectively. Sequencing of gltA fragments identified R. felis genotype URRWXCal2 in samples from both countries, and genotype Rf2125 in …

Modeling Diffusion In Social Networks Using Network Properties, Duc Minh Luu, Ee Peng Lim, Tuan Anh Hoang, Chong Tat Freddy Chua

Research Collection School Of Computing and Information Systems

"Diffusion of items occurs in social networks due to spreading of items through word of mouth and exogenous factors. These items may be news, products, videos, advertisements or contagious viruses. When a user purchases or consumes one of such items, we say that she adopts the item and she becomes an item adopter. Previous research has studied diffusion process at both the macro and micro levels. The former models the number of item adopters in the diffusion process while the latter determines which individuals adopt item. Both macro and micro level models have their merits and limitations. In this paper, …

Virality And Susceptibility In Information Diffusions, Tuan-Anh Hoang, Ee Peng Lim

Research Collection School Of Computing and Information Systems

Viral diffusion allows a piece of information to widely and quickly spread within the network of users through word-ofmouth. In this paper, we study the problem of modeling both item and user factors that contribute to viral diffusion in Twitter network. We identify three behaviorial factors, namely user virality, user susceptibility and item virality, that contribute to viral diffusion. Instead of modeling these factors independently as done in previous research, we propose a model that measures all the factors simultaneously considering their mutual dependencies. The model has been evaluated on both synthetic and real datasets. The experiments show that our …

Coherent Pattern Prediction In Swarms Of Delay-Coupled Agents, Luis Mier-Y-Teran-Romero, Eric Forgoston, Ira B. Schwartz

Department of Applied Mathematics and Statistics Faculty Scholarship and Creative Works

We consider a general swarm model of self-propelling agents interacting through a pairwise potential in the presence of noise and communication time delay. Previous work has shown that a communication time delay in the swarm induces a pattern bifurcation that depends on the size of the coupling amplitude. We extend these results by completely unfolding the bifurcation structure of the mean field approximation. Our analysis reveals a direct correspondence between the different dynamical behaviors found in different regions of the coupling-time delay plane with the different classes of simulated coherent swarm patterns. We derive the spatiotemporal scales of the swarm …

Simplified Models Of Vector Control Impact Upon Malaria Transmission By Zoophagic Mosquitoes, Samson S. Kiware, Nakul Chitnis, Sarah J. Moore, Gregor J. Devine, Silas Majambere, Stephen Merrill, Gerry F. Killeen

Mathematics, Statistics and Computer Science Faculty Research and Publications

Background

High coverage of personal protection measures that kill mosquitoes dramatically reduce malaria transmission where vector populations depend upon human blood. However, most primary malaria vectors outside of sub-Saharan Africa can be classified as “very zoophagic,” meaning they feed occasionally (

Methods and Findings

We extended a published malaria transmission model to examine the relationship between transmission, control, and the baseline proportion of bloodmeals obtained from humans (human blood index). The lower limit of the human blood index enables derivation of simplified models for zoophagic vectors that (1) Rely on only three field-measurable parameters. (2) Predict immediate and delayed (with …

An Agent Based Model Of Tumor Growth And Response To Radiotherapy, Nicole O'Neil

Theses and Dissertations

An agent based model was developed to examine the growth of a tumor in a healthy cell population. Response to radiation and impact of mutation and bystander effects were studied. In the growth model, the cancer cells proliferated outward becoming invasive. The mass of cancer cells developed a necrotic core. Various treatment protocols of radiation were compared. Timing of treatments was critical to the success of therapy. The event of mutation was rare. When mutation occurred, either unsuccessful treatment or re-growth could result. Multiple rounds of radiation potentially led to increased mutation. Low levels of the bystander effect had little …

Synthesis Of S-Ribosyl-L-Homocysteine And Analogs Modified At The Homocysteine-C3 Position, Ruoyi Liu

Master's Theses

Quorum sensing (QS) is a process of bacterial cell-to-cell communication that conveys population density information in order to coordinate gene expression to produce synchronized behaviors. QS regulates the expression of virulence genes in many species of bacteria; hence, the manipulation of QS pathways may lead to treatment options against many bacterial diseases. The LuxS enzyme converts S-ribosyl-L-homocysteine (SRH) into homocysteine (HCys) and 4(S),5-dihydroxypentane-2,3-dione (DPD), which is the precursor of autoinducer-2 (AI-2). Thus, inhibitors of LuxS could prevent QS by halting the conversion of SRH to AI-2 rendering the cell “uncommunicative”. This work shows the successful chemical synthesis …

Population Based Model Of Gonorrhea And Interventions Against Increased Antibiotic Resistance, Courtney Henry

Theses and Dissertations

Gonnorrhea is an infectious sexually transmitted disease (STD) caused by the bacterium Neisseria gonorrhoeae that commonly reproduces in the reproductive tract.The Centers of Disease Control and Prevention (CDC) estimate that more than 700,000 individuals in the U.S. contract new gonorrheal infections per year. During recent years, there has been a progressive global increase of drug-resistant strains of gonorrhea. Therefore, there exists the necessity for health organizations to encourage the monitoring, research and development of innovative treatment regimens. We have developed multiple mathematical models to explore the gonorrheal disease state. The first objective of model formulation was to fit the model …

The Analysis Of Protein-Bound Thiocyanate In Plasma Of Smokers And Non-Smokers As A Marker Of Cyanide Exposure, Stephanie L. Youso, Gary A. Rockwood, Brian A. Logue

Chemistry and Biochemistry Faculty Publications

When cyanide is introduced into the body, it quickly transforms through a variety of chemical reactions, normally involving sulfur donors, to form more stable chemical species. Depending on the nature of the sulfur donor, cyanide may be transformed into free thiocyanate, the major metabolite of cyanide transformation, 2-amino-2-thiazoline-4-carboxylic acid or protein-bound thiocyanate (PB-SCN) adducts. Because protein adducts are generally stable in biological systems, it has been suggested that PB-SCN may have distinct advantages as a marker of cyanide exposure. In this study, plasma was analyzed from 25 smokers (chronic low-level cyanide exposure group) and 25 non-smokers for PB-SCN. The amount …

A Mathematical Model For Dengue Fever In A Virgin Environment, Jason K. Bowman

Senior Honors Projects

Dengue is a mosquito-borne viral infection found in tropical and subtropical regions around the world. The disease was named in 1779 and the first recorded epidemic of it occurred simultaneously on three continents within the following decade. Dengue is characterized by flu-like symptoms and, while its symptoms are generally reported as quite unpleasant, is rarely fatal. However, in some cases patients can contract a more serious form of the disease, known as Dengue Hemorrhagic Fever, which is far more dangerous. The World Health Organization estimates that today over 2.5 billion people are at risk for Dengue (over 40% of the …

The Length-Biased Lognormal Distribution And Its Application In The Analysis Of Data From Oil Field Exploration Studies, Makarand V. Ratnaparkhi, Uttara V. Naik-Nimbalkar

Journal of Modern Applied Statistical Methods

The length-biased version of the lognormal distribution and related estimation problems are considered and sized-biased data arising in the exploration of oil fields is analyzed. The properties of the estimators are studied using simulations and the use of sample mode as an estimate of the lognormal parameter is discussed.

The Persistence Of Infectious Diseases In Metapopulations, Jonathan Calvin Hayes

Theses, Dissertations and Culminating Projects

Mathematical models provide a great deal of information about the dynamics of disease spread. In this paper, we use stochastic simulation to investigate spontaneous disease extinction and réintroduction in a SIR model. We begin by investigating path to extinction and time to extinction in single population models, and then expand to a multipopulation model linked with linear migration. We have found that in a single population model, it is more effective to use random pulse vaccinations less per year at a higher removal rate. We have expanded this result by developing a vaccination strategy giving one large, well timed pulse …

A Leishmania Mitogen Activated Protein Kinase As A Potential Anti-Parasitic Drug Target : Purification, Characterization And Inhibitor Interactions, Aysenur Sayakci

Theses, Dissertations and Culminating Projects

The disease, Leishmaniasis, is caused by the protozoal parasite Leishmania, which is transmitted by the bite of an infected Phlebotomine female sandfly. It is a significant health problem in tropical regions of the world and new therapeutic approaches for treating this disease are urgently needed.

Protozoal MAPKs (Mitogen Activated Protein Kinases) play important roles in parasite viability and infectivity and as such, represent viable drug targets. It has been demonstrated that LmxMPKl is an essential MAPK required for the parasite to establish infection and for proliferation of the amastigote stage (the mammalian stage of the parasite) of the parasite. In …

Genomic Analysis Of Immune Response Against Vibrio Cholerae Hemolysin In Caenorhabditis Elegans, Surasri N. Sahu, Jada Lewis, Isha Patel, Serdar Bozdag, Jeong H. Lee, Joseph E. Leclerc, Hediye Nese Cinar

Mathematics, Statistics and Computer Science Faculty Research and Publications

Vibrio cholerae cytolysin (VCC) is among the accessory V. cholerae virulence factors that may contribute to disease pathogenesis in humans. VCC, encoded by hlyA gene, belongs to the most common class of bacterial toxins, known as poreforming toxins (PFTs). V. cholerae infects and kills Caenorhabditis elegans via cholerae toxin independent manner. VCC is required for the lethality, growth retardation and intestinal cell vacuolation during the infection. However, little is known about the host gene expression responses against VCC. To address this question we performed a microarray study in C. elegans exposed to V. cholerae strains with intact and deleted hlyA …

Robust Computational Tools For Multiple Testing With Genetic Association Studies, William L. Welbourn Jr.

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The mapping of the human genome and the completion of the Human HapMap project over the past decade have significantly altered how research is conducted with respect to the genetic epidemiology of human disease. Study designs and analytic approaches have evolved rapidly from investigations involving relatively few targeted candidate genes to hypothesis-free genome-wide association studies, where thousands – and now even millions – of single molecular mutations are simultaneously analyzed to identify regions of the genome that may influence disease. As laboratory techniques continue to improve and costs decrease, the volume of genetic data will inexorably rise, and robust tools …

Demographics And Survival Of Aids Cases With Cancer, Washington, Dc, 1996-2006, Heather A. Young, Eric Engels, Anne-Marie Sufian-Kargbo, Alicia Vargas, Kathleen Rogers, Tiffany West, Amanda D. Castel

Epidemiology Faculty Publications

Background

Washington, DC (DC) has one of the highest HIV/AIDS rates in the U.S and cancer is the second leading cause of death among DC residents. This study sought to examine the demographic characteristics and survival of persons with AIDS defining cancers (ADCs) compared to those with non-AIDS defining cancers (NADCs) between the early HAART era (1996-2001) and the late HAART era (2002-2006) in DC.

Methods

Cases reported from 1996-2006 to the DC Cancer Registry and the AIDS Surveillance Registry were linked using a probabilistic matching algorithm. Cases were included if the cancer occurred from 4 months to 60 months …

Clean Water In Haiti, Hannah Mchugh

2012 Awards for Excellence in Student Research & Creative Activity - Documents

In the past few years, Haiti has been a topic that has been in the news here in the United States for many reasons. These reports typically show the faces of hundreds of starving and injured Haitians who live in turmoil and they discuss the disasters that have befallen the country. While these reports do not usually show the more pleasant aspects, they are relatively accurate in showing the state of the majority of the country. A major impact on a country that is in such a dire state is the presence and availability of clean water. But to understand …

Evaluation And Verification Of Washing Practices On Pathogen Recovery And Survival On Produce, Wilbert Long Iii

Student Theses and Dissertations

Food sanitation is a very important issue that affects the global market. Proper sanitation can help reduce microbial pathogens which influence public health by causing illnesses and death and financial resources (e.g. time lost at work, loss of produce due to spoilage, and recalls). In a number of incidences, foods may be reported as extremely susceptible to pathogens and are denoted as potentially hazardous by health organizations such as the Food and Drug Administration (FDA) and state institutions. Pathogenic contamination of foods may be caused by factors that include growing environment, handling, processing, produce structure, water activity (the amount of …

How Does Climate Change Affect Agricultural Stability In Southeast Unguja? An Assessment Of The Threats To Agriculture And Food Security From Rising Temperature And Changes In Predictability And Intensity Of Rainy Seasons., Eloise Reid

Independent Study Project (ISP) Collection

The relationship between climate change, agriculture, and food security on the island of Unguja was studied. Informal interviews were carried out in the south-eastern coastal communities of Bwejuu, Paje, and Jambiani in order to gain perspective and awareness of local knowledge concerning changes in climate and it's affects on crop production. Formal interviews were conducted in Stone Town with the Ministry of Agriculture, the Department of Environment, the Sustainable Management of Land and the Environment office, private climate change experts and environmental consultants, and local NGO's to gain insight on what aspects of climate change are most detrimental in the …

A Conceptual Model To Facilitate Amphibian Conservation In The Northern Great Plains, David M. Mushet, Ned H. Euliss Jr., Craig A. Stockwell

Great Plains Research: A Journal of Natural and Social Sciences (through 2013)

As pressures on agricultural landscapes to meet worldwide resource needs increase, amphibian populations face numerous threats including habitat destruction, chemical contaminants, disease outbreaks, wetland sedimentation, and synergistic effects of these perturbations. To facilitate conservation planning, we developed a conceptual model depicting elements critical for amphibian conservation in the northern Great Plains. First, we linked upland, wetland, and landscape features to specific ecological attributes. Ecological attributes included adult survival; reproduction and survival to metamorphosis; and successful dispersal and recolonization. Second, we linked ecosystem drivers, ecosystem stressors, and ecological effects of the region to each ecological attribute. Lastly, we summarized information on …

Modeling The Dispersion Of Eastern Oyster Larvae (Crassostrea Virginica) And Its Effects On The Movement Of Disease Resistant Genes In The Delaware Bay Estuary, Diego A. Narvaez

OES Theses and Dissertations

This study combines several models to address two primary research questions. How does the interaction of larval biology and environmental variability determine the spatial distribution of oyster larvae in Delaware Bay? What is the role of larval dispersion in the transference of disease-resistant genes? The particle-tracking module in the Regional Ocean Modeling System (ROMS) was converted into an Individual-Based model representing Eastern oyster larvae that has growth and vertical migration. Exchange of larvae between natural oyster reefs was estimated and used in an Individual-Based genetic model that simulates the genetic structure of eastern oysters. Particles were released from a number …

Investigation And Synthesis Of Novel Graphene-Based Nanocomposites For Hydrogen Storage, Anthony Joseph D'Angelo

USF Tampa Graduate Theses and Dissertations

It is of great interest to develop and utilize a high surface area material with optimized hydrogen sorption properties. The need for a renewable energy source to replace automobile gasoline has become more critical in the past decade. Hydrogen is a viable fuel source for automobile usage; however, the question of how hydrogen will be safely and efficiently stored still remains. Critical factors for optimum hydrogen storage include ambient conditions and low activation temperature for adsorption and desorption phenomena. In order for optimum hydrogen adsorption to be achieved, the properties of (1) high surface area, (2) optimum hydrogen adsorption energy, …

Race And Hepatitis C Management Within The Veterans Administration, Joahd Toure, Joshua Metlay, Sandford Schwartz, Knashawn Morales, David Kaplan, Peter Groeneveld

Journal of Health Disparities Research and Practice

Objective: To examine black-white differences in hepatitis C treatment within the Veterans Administration (VA) and determine whether racial variation in specialty consultation explains differences in hepatitis C treatment between blacks and whites.

Methods: We performed a retrospective cohort study of 1040 veterans meeting VA eligibility criteria for hepatitis C treatment. We used multiple imputation to handle missing race data. Specialty consultation was determined from the VA outpatient medical dataset and hepatitis C treatment was determined from the VA decision support system. Conditional logistic regression was used to examine the association between race and hepatitis C treatment as well as race …

Probe Functionalization With A Rhop-3 Antibody: Toward A Rhop-3 Antigen Immunosensor For Detection Of Malaria, Salaam Saleh, Susan Moreno Molek, Perera N. Indika, Alan Riga, Tobili Sam Yellowe, Mekki Bayachou

Chemistry Faculty Publications

The antibody specific for the malaria protein, Rhop-3, and FL-Rhop-3, were immobilized on the surface of a gold electrode modified with cysteamine. Colloidal gold was used to enhance the detection signal for Rhop-3 antigens. The Rhop-3 antibody was also immobilized on gold electrodes preactivated with dithiobis(succinimidyl proprionate) (DSP). Immobilization was performed at room temperature and at 37 °C. Cyclic voltammetry (CV) was used to monitor the interaction between the immobilized antibody and its cognate antigen in solution, using ferricyanide, K3Fe(CN)6, as reporting electroactive probe. Tests indicate recognition of Rhop-3 protein by the immobilized antibody. Antigen recognition was enhanced by incubation …

Reversed Chloroquine Molecules As A Strategy To Overcome Resistance In Malaria, David H. Peyton

Chemistry Faculty Publications and Presentations

This short review tells the story of how Reversed Chloroquine drugs (RCQs) were developed. These are hybrid molecules, made by combining the quinoline nucleus from chloroquine (CQ) with moieties which are designed to inhibit efflux via known transporters in the membrane of the digestive vacuole of the malaria parasite. The resulting RCQ drugs can have potencies exceeding that of CQ, while at the same time having physical chemical characteristics that may make them favorable as partner drugs in combination therapies. The need for such novel antimalarial drugs will continue for the foreseeable future.

Incorporating Quantitative Reasoning In Common Core Courses: Mathematics For The Ghost Map, John R. Jungck

Numeracy

How can mathematics be integrated into multi-section interdisciplinary courses to enhance thematic understandings and shared common readings? As an example, four forms of quantitative reasoning are used to understand and critique one such common reading: Steven Berlin Johnson’s "The Ghost Map: The Story of London's Most Terrifying Epidemic - and How it Changed Science, Cities and the Modern World" (Riverhead Books, 2006). Geometry, statistics, modeling, and networks are featured in this essay as the means of depicting, understanding, elaborating, and critiquing the public health issues raised in Johnson’s book. Specific pedagogical examples and resources are included to illustrate applications and …

Stable Coexpression Of Vitamin C Enhancing Genes For Improved Production Of A Recombinant Therapeutic Protein, Hil-12, In Arabidopsis Thaliana, Jessica Patricia Yactayo-Chang

Student Theses and Dissertations

Human interleukin-12 (hIL-12) has been studied as a potential therapeutic factor in the immune response against viral disease and cancer. Plants are a promising platform for the production of complex mammalian proteins, as they can produce large amounts of functional polypeptides free of animal pathogens, and protein production can be increased to agricultural scale in a relatively short period of time. The presence of vitamin C (ascorbic acid, AsA) has been reported to have a positive effect on recombinant protein recovery. In a previous study we have demonstrated the favorable impact of the exogenous addition of AsA on the accumulation …

The Equation, Winter 2012, College Of Science And Mathematics, Wright State University

College of Science and Mathematics Newsletters

This 39 page newsletter discusses various happenings within the College of Science and Mathematics. It begins with a letter from the dean, and continues on with news, events, alumni news, and other community news.

Internship Report Unep: The Effects Of Climate Change In Arctic Zones, Diana Cartaya-Acosta

Student Theses 2001-2013

Climate change or the significant alteration of major weather pattern distributions around the planet over long time periods, is one of the most significant phenomena currently affecting our planet.Arctic as one of the most sensitive zones in terms of damaged it is by climate change effects.The consequences of the many representations of climate change are distributed in a geographically unequal manner, therefore it is a global major concern to target and mitigate related issues that are already directly affecting several populations.

Even tough geographically distinct and distant populations are likely to face climate change related catastrophes at different rates, many …

Utility Of Improvised Video-Camera Collars For Collecting Contact Data From White-Tailed Deer: Possibilities In Disease Transmission Studies, Michael J. Lavelle, Scott E. Hygnstrom, Aaron M. Hildreth, Tyler A. Campbell, David B. Long, David G. Hewitt, Jeff Beringer, K. C. Vercauteren

School of Natural Resources: Faculty Publications

Rapidly evolving electronic technology enables wildlife researchers to collect previously unobtainable data. To explore possibilities of using deer-borne cameras (DBCs) to collect behavioral data from an animal’s point of view, we constructed DBCs and deployed them on 26 adult male whitetailed deer (Odocoileus virginianus) within a closed population (405-ha fenced area) in southern Texas just prior to the breeding season during autumn 2010. Our DBCs consisted of global positioning system collars with attached motion-activated trail cameras. We obtained 21,474 video clips from 17 functional DBCs over a period of 14 days. Individual-based data are invaluable in disease and …