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CEPCEB Members
I received my Ph.D. in Environmental Engineering, from the Department of Chemical Engineering at Yale University in 2004. I also earned my M.S. in Chemical and Environmental Engineering from Yale in 2000 and two Bachelor of Science degrees from the University of Southern California in Environmental Engineering and Environmental Studies in 1998. I am an active member of the American Chemical Society (ACS) and American Institute of Chemical Engineers (AIChE). I am also a member of the American Society of Microbiology (ASM), Association for Environmental Engineering and Science Professors (AEESP), Association of Women in Science (AWIS), and Society of Women Engineers (SWE). I am currently a faculty advisor to the UC Riverside Alpha Beta chapter of Tau Beta Pi and campus chapter of SWE. Research Interests My expertise lies at the intersection of physical, chemical, and biological processes in natural and engineered aquatic systems. In particular, my work has focused on understanding the factors controlling bacterial adhesion and transport in subsurface environments. My research group focuses on the nature of bacterial cell surface polymers – lipopolysaccharides (LPS) and extracellular polymeric substances (EPS) – and their role in adhesion. The relative influence of bacterial surface polymers on cell adhesion and transport in aquatic systems is examined using natural isolates, wild type, and mutants of Escherichia coli, Salmonella spp., and Burkholderia cepacia. This is assessed through the utilization of cell characterization techniques in combination with deposition studies in packed bed column, a radial stagnation point flow (RSPF), and parallel plate chamber systems under well-controlled solution and collector surface chemistries. My overall research goal is to establish the mechanisms contributing to pathogen interactions with surfaces. Ultimately these mechanisms will influence the fate and transport of these pathogens in aquatic environments. Particular emphasis is placed on groundwater systems; however, vadose zone and surface water systems are also studied. This work is imperative for properly assessing the environmental impact of groundwater contamination from sources including urban runoff, septic tank/leach field systems, and animal manure from agricultural operations. The information is also vital for effective design of water quality technologies including riverbank filtration, wastewater reclamation, and recharge into aquifers. Additionally, with this crucial knowledge, design of surface coatings and processing can be optimized for minimal biofouling in marine environments. The specific areas of research currently being conducted are as follows:
Area 1. Role of Chemical and Physical Heterogeneity on Bacterial Cell Adhesion Thisresearch effort focuses on the interactions occurring between a model particle (bacterium as well as a polystyrene colloid) and collector surfaces in simulated seawater or groundwater environments. Both the physical and chemical heterogeneous nature of the particle and collector surfaces is systematically modified and the extent to which altering this influences adhesion is quantified within a packed-bed column, a parallel plate (PP) flow cell, and the radial stagnation point flow (RSPF) system. Collector surface modification is done utilizing a sintering technique or by zeolite coating, which allows for nanometer scale control of both chemical and physical surface features. The intent of this work is to establish the role of heterogeneity on the adhesion of bacteria which lead to biofilm development. (Collaborators: Prof. Yushan Yan, Chemical and Environmental Engineering Dept., UCR; Assistant Prof. Javier Garay, Mechanical Engineering Dept., UCR)
Area 2. Influence of Extracellular Polymeric Substances (EPS) on Cell Adhesion and Transport. This project is examining the extent to which transport of pathogens in porous media is controlled via cell surface polymers. Specifically, the impact of bacterial metabolic and environmental conditions on EPS production and composition (relative amounts of protein, polysaccharide, and nucleic acid content) and subsequent influence on adhesion is being assessed using packed bed column experiments. Parameters such as pore water content, temperature, solution chemistry, and bacterial cell condition are systematically varied to simulate subsurface conditions. Additionally, the influence of these parameters on the genotype of the cell is being investigated, and ultimately the effect on pathogen virulence can be assessed. (Collaborator: Professor Heather Smith, Riverside Community College; Funding: National Water Research Institute, UC Center for Water Resources, USDA CSREES HSI)
Area 3. Coupled Role of Physical and Chemical Interactions in Pathogen Transport in Porous Media This research effort combines experimental and theoretical methodologies at several spatial scales. Extended DLVO theory calculations and direct measurement of pathogen-pathogen interaction forces using atomic force microscopy (AFM) are being utilized to determine colloid-colloid and colloid-collector grain interaction energies. Packed bed column experiments and real time direct observation of pore-scale deposition processes using the RSPF are being conducted to determine the dominant deposition mechanisms. In addition to current colloid studies, a model E. coli and Cryptosporidium will be utilized in the future. (Collaborators: Prof. Bill Johnson at the University of Utah and Dr. Scott Bradford at the USDA-ARS Salinity Laboratory; Funding: USDA CSREES NRI)
Graduate advisor (Ph.D.):
Post-doctoral advisor:
Visiting graduate students:
Undergraduate researchers:
Riverside Community College students: (as part of the USDA Bridges Across Riverside through Water Quality Research Program)
Selected Publications (Bibliography page)
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