Postdoctoral Profiles

Jason R. Pirone, Ph.D.

Biomathematics and Toxicology (co-Ph.D.), North Carolina State University

The ability to explore complex biological problems and to simultaneously assess how your research fits within the larger context of risk assessment is a unique aspect of working at the NCCT. I enjoy working in a truly interdisciplinary environment where modelers and experimentalists work collaboratively on problems of immediate relevance to human and ecological health.

Virtual Liver Project
The goal of the Virtual Liver Project is the development of a mathematical model capable of describing the biochemical and structural alterations in the liver as a result of chronic exposure to environmental chemicals. There are three levels of biological detail at which simulations will be conducted: (i) the dynamics of perturbed molecular pathways, (ii) their linkage with adaptive or adverse processes leading to alterations of cell state, and (iii) the integration of the molecular and cellular responses into a physiological tissue model. My effort will focus on modeling the molecular perturbations in biochemical and genetic networks important in the responses of the liver to xenobiotics. Specifically, I will focus on a subset of nuclear receptor (NR) signaling and genetic regulatory pathways involved in xenobiotic metabolism and other cellular processes. Techniques used will include stochastic and deterministic methods for simulating dynamic systems, as well as more empirical methods for analyzing high-dimensional data sets.

David Reif, Ph.D.

Human Genetics, Vanderbilt University
Postdoctoral Fellow, EPA's National Center for Computational Toxicology

The sense of shared mission is what I enjoy most about my work at NCCT. I find motivation in working with people who are looking toward common goals.

Evaluating Complex Relationships Between Environmental Factors and Human Health
The human body and its interaction with the environment comprise an extremely complicated system. To understand how environmental disease develops, we need to be able to consider a wide range of information on both external environmental factors (e.g., ambient air quality, chemical exposure) and internal biological factors (e.g., genetic variation, protein expression). We are developing novel analysis approaches to characterize the interactions among these many environmental and biological factors, with the goal of painting a more comprehensive picture of the role that our environment plays in development of diseases such as asthma, diabetes, and autism.

Chester Rodriguez, Ph.D.

Pharmacology, University of California, Los Angeles
Postdoctoral Fellow, EPA's National Center for Computational Toxicology

NCCT offers excellent training for postdoctoral fellows for utilizing the latest computational technologies for environmental-protection-driven research. I particularly enjoy using sophisticated computer simulation programs to better understand pharmacokinetics. I also value the excellent mentorship by established leaders in the field.

Changes in Rat Pharmacokinetics with Age
In this project, we are developing mathematical models to describe how the body handles chemicals, and how this ability is affected by age. The body can be very efficient in eliminating some chemicals, while it can retain others for a long time or even transform them into more toxic forms. The goal is to use mathematical models to better understand the effects of age on the body's ability to handle chemicals and, thus, better assess potential risks to human health.

John Wambaugh, Ph.D.

Physics, Duke University
Postdoctoral Fellow, EPA's National Center for Computational Toxicology

I enjoy interacting with the diverse group of people who make up NCCT they are from a wide range of backgrounds academically and personally, and I learn a great deal from every interaction. In my research, I have enjoyed finding new ways to apply techniques I have learned in the past to new, sometimes very different problems, while also learning new scientific approaches.

Statistical Analyses of Pharmacokinetic Modeling
Everyone's body is different. Chemicals behave differently in different people. Pharmacokinetics tries to determine what your body does to a chemical where it goes while it's there, how long it stays, and what eventually happens to it. These properties can be measured for individuals in an experiment, and, from that, we infer how that chemical would behave in the population as a whole. But what if the individuals in the experiment were somehow unusual? In this project, we use computers to examine millions of possible populations from which the subjects of an experiment might have come, so that we can find a range of likely populations. This tells us exactly how certain we are about the chemical's behavior in the population as a whole.

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