Physical Sciences and Mathematics Commons^™

Utilizing Consumer Health Posts For Pharmacovigilance: Identifying Underlying Factors Associated With Patients’ Attitudes Towards Antidepressants, Maryam Zolnoori

Theses and Dissertations

Non-adherence to antidepressants is a major obstacle to antidepressants therapeutic benefits, resulting in increased risk of relapse, emergency visits, and significant burden on individuals and the healthcare system. Several studies showed that non-adherence is weakly associated with personal and clinical variables, but strongly associated with patients’ beliefs and attitudes towards medications. The traditional methods for identifying the key dimensions of patients’ attitudes towards antidepressants are associated with some methodological limitations, such as concern about confidentiality of personal information. In this study, attempts have been made to address the limitations by utilizing patients’ self report experiences in online healthcare forums to …

Modeling Of Anticancer Drug Delivery By Temperature-Sensitive Liposomes, Vera Franziska Loeser

Theses and Dissertations

Cytotoxic anticancer drugs are used to treat cancer, particularly tumors. These drugs themselves do not distinguish between healthy and tumor cells and attack all of them. Consequently physicians and chemists investigate safer ways of delivery that minimize damage to healthy cells. One of these ways are liposomal formulations of the anticancer drugs. Liposomes are vesicles that encapsulate the drug to shield the healthy parts of the body from the toxicity of the drugs. Due to the abnormal structure of tumors, especially their leaky vasculature, these macromolecules are able to diffuse into the tumor tissue whereas the normal vasculature prevents them …

Computational Fluid Dynamics In A Terminal Alveolated Bronchiole Duct With Expanding Walls: Proof-Of-Concept In Openfoam, Jeremy Myers

Theses and Dissertations

Mathematical Biology has found recent success applying Computational Fluid Dynamics (CFD) to model airflow in the human lung. Detailed modeling of flow patterns in the alveoli, where the oxygen-carbon dioxide gas exchange occurs, has provided data that is useful in treating illnesses and designing drug-delivery systems. Unfortunately, many CFD software packages have high licensing fees that are out of reach for independent researchers. This thesis uses three open-source software packages, Gmsh, OpenFOAM, and ParaView, to design a mesh, create a simulation, and visualize the results of an idealized terminal alveolar sac model. This model successfully demonstrates that OpenFOAM can be …

Mathematical Models Of The Inflammatory Response In The Lungs, Sarah B. Minucci

Theses and Dissertations

Inflammation in the lungs can occur for many reasons, from bacterial infections to stretch by mechanical ventilation. In this work we compare and contrast various mathematical models for lung injuries in the categories of acute infection, latent versus active infection, and particulate inhalation. We focus on systems of ordinary differential equations (ODEs), agent-based models (ABMs), and Boolean networks. Each type of model provides different insight into the immune response to damage in the lungs. This knowledge includes a better understanding of the complex dynamics of immune cells, proteins, and cytokines, recommendations for treatment with antibiotics, and a foundation for more …

Marginal Structural Cox Model For Survival Data With Treatment-Confounder Feedback, Yanan Zhang

Theses and Dissertations

In an observational longitudinal study, there can be time-varying exposure/treatment and time-varying confounders. When the confounders affect the exposure and prior exposure also has an impact on levels of confounders, there is treatment confounder feedback. To admit estimation of unbiased causal effects, these conditions need to be hold, exchangeability, positivity, consistency. The traditional method of conditioning on potential confounders does not meet these 3 conditions. Therefore, parameter estimates from traditional Cox model are biased casual effect estimates when the treatment confounder feedback exists. The marginal structural Cox model can be used to address this issue. By calculating and including inverse …

Weighted Quantile Sum Regression For Analyzing Correlated Predictors Acting Through A Mediation Pathway On A Biological Outcome, Bhanu M. Evani

Theses and Dissertations

Abstract

Weighted Quantile Sum Regression for Analyzing Correlated Predictors Acting Through a Mediation Pathway on a Biological Outcome

By

Bhanu M. Evani, Ph.D.

A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University.

Virginia Commonwealth University, 2017.

Major Director: Robert A. Perera, Asst. Professor, Department of Biostatistics

This work examines mediated effects of a set of correlated predictors using the recently developed Weighted Quantile Sum (WQS) regression method. Traditionally, mediation analysis has been conducted using the multiple regression method, first proposed by Baron and Kenny (1986), which has since …

Comparison Of Atypical Bacteriophages That Infect Caulobacter Crescentus, Doreen Nguyen

Theses and Dissertations

Several Caulobacter bacterial genomes have been recently sequenced, and all of the genomes contained one or more clusters of genes with phage origins. This observation indicates that bacteriophages contribute to the Caulobacter gene pool, so in order to understand bacteria genomes we will need to understand phage genomes as well. As part of understanding the phage genomes, we want to isolate novel bacteriophages and study their genomics. This study resulted in the isolation of 12 new phages, including four that differ from the well-studied CbKlike phages. Two of these novel phages are Podoviruses with icosahedral heads and small tails, and …