I Exposure Assessment Charles Gerba - UA Chris Choi UA Mark Nicas UCB Paul Kiem NAU Syed Hashsham - MSU Group 1: Exposure Development of decay constants Surrogate development and assessment U of A NAU MSU U of A NAU QMRA
Detection methodology development (for surrogates and assessment) Development of Exposure Models U of A U of C Drexel MSU MSU Transport and Fate Studies Aerosols U of C U of A NAU Water
Fomites U of A MSU Soil NAU U of A NAU NAU MSU Overall Objectives Development of new BAC surrogates for application in methods assessment and transport and fate modeling efforts. Validation of detection methods for microbial risk
assessment. Development of fate and transport models for BAC on fomites. Development of fate and transport models for BAC in water systems. Development and validation of a discrete-time Markov chain model for airborne BAC within a room. Measure the re-suspension of particle-associated BAC in a test room or chamber Determine the particle size distribution of respiratory aerosol Year 1
Assessment of coliphage surrogates Characterization of PRD1/MS-2 as surrogates Assessment of fomite sampling protocols Development of k values (decay rates) Anthrax detection methods sensitivity Identification of anthrax surrogates Improvement to distribution system transport model Improvement to Markov Chain model Assessment of Phage Surrogates PRD-1 and MS-2 being assessed (most extensively used phage models) PRD-1, which has been extensively used
previously as a model appears to actually be P22 Primers developed and assess for PRD-1 application Sampling methods and survival on various fomites assessed Variability and Associated Recovery Methods from Fomites 1.2 PRD-1 - Three Methods 1 Cotton Sw ab Electrostatic Wiping Rinsing w / Squeegee logct / logc0 0.8 0.6
Fellowes 4.4 8.9 Decay Rate on Fomites (K) To be useful in model predictive models on the fate of agents of concern information on their decay on fomites needs to be normalized from various studies published in the literature. The existing literature was reviewed and data on agent decay was normalized against environmental conditions This data can now be used in models to predict survival of these agents on fomites. It was found
that enteric viruses survive for days to months on surfaces compared to hours to days for respiratory viruses. es pi ra to ry lu en za ** vi ru s vi ru
s2 14 43 0.5 sy nc yt ia l ai nf ru s -O C
0.3 R Pa r hi no vi av iru s --2 29 E 0.167
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A 0.1 In fl u en za In fl u en za Log10 reduction per hour Respiratory virus inactivation rates (K) 0.7 0.625
0.6 0.5 0.4 0.25 0.2 0.0417 0 Limit of Detection Methods for Anthrax in Water Real time polymerase chain reaction (PCR), conventional PCR, and selected antibody based and chemiluminiscence assays are among the most sensitive
detection methods is one of the main accomplishments this year. A similar analysis for air and soil is also complete with similar conclusions. Distribution of detection limit: various methods available to detect Anthrax in water Quantum dots as surrogates* of bacterial pathogens (*Only selected characteristics) EviDot:CdSe/ZnS Core-shell Approx diameter 2-5 nm Non bio-available EviTag: Quantum dots with PEG lipid surface coating coupled to amine terminal groups Approx. hydrodynamic diameter
25nm Bio-available DNA strands can be attached EviFluor: antibodies or protein conjugated EviTag Approx. hydrodynamic diameter 25nm Bio-available DNA strands can be attached Fluorescence varies with size of QD (2nm-5nm) EviTag with green fluorescence (diameter ~25nm emission 520nm) was used Comet Assay DNA Break is taken as an indication of genotoxicity
ALKALINE ELECTROPHORESIS Normal Human Lymphocytes STAINING (EtBr) Lymphocyte Showing DNA Damage Effect of quantum dots on human lymphocytes: DNA damage by Comet assay 250 *** Tail moment (Arbitrary units) 200 *** *p<0.05,**p<0.01, ***p<0.001 150
400nM QD Concentrations Values mean+ SD; Cell viability in all the treatment concentrations >90%; Positive control (EMS 2mM)- Tail moment >350 Distribution System Fate and Transport Modeling Fate & Transport in Water System Investing water quality models at intersections of pressurized pipe systems Experimental verifications have been carried out at the Water Village. Creating several scenarios in order to generate training and testing data required for a backpropagation Artificial Neural Network (ANN)
with six input (water demands) and six output (average concentration) units. Distribution System Modeling EPANET-based Simulation RISK ASSESSMENT -HD Model - WQ Model ANN-based Prediction Models Indicator Microorganisms Experimental Validation using Water-Distribution Networks at the Water Village
Key Components of a Typical Drinking Water System & Their Vulnerabilities Water Systems & Microbiology Laboratory Water Distribution Systems Laboratory Mixing patterns along the interface Corresponding Risk Microbial Risk Assessment & Consequences Distribution System Fate and Transport Modeling - Contributions Corrections in EPANET model and further calibration Construction of distribution system network and initial model testing Modeling Airborne Fate and Transport of Agents of Concern
Refinement of a simple Markov Chain Model Development method for incorporating information on air velocity and turbulent intensity values Validate Markov chain particle model via published data Construct test chamber Year-1 Publications Boone, S. A. and C. P. Gerba 2006. The significance of fomites in the spread of respiratory and gastrointestinal disease. Applied and Environmental Microbiology, In Press. Romero-Gomez, P., C. Y. Choi, B. van Bloemen Waanders, and S. McKenna, Transport Phenomena at Intersections of Pressurized Pipe Systems, 2006, 8th Annual Water Distribution Systems Analysis Symposium, Cincinnati, OH.
Alok K. Pandey, Amanda B. Herzog, Joan B. Rose, Syed A. Hashsham. Potential of Quantum Dots as Surrogates for Microbial Pathogens and Evaluation of Their Genotoxicity. 107th General Meeting of the American Society for Microbiology, Toronto, Canada, May 21-25, 2007. Amanda B. Herzog, Alok Pandey, Tomoyuki Shibata, Joan B. Rose, and Syed A. Hashsham. Implications of Detection Limit of Various Methods of Bacillus anthracis in Computing Risk to Human Health. 107th General Meeting of the American Society for Microbiology, Toronto, Canada, May 21-25, 2007. Year 2 Determine attenuation rates of various Bacillus species under natural conditions. B. anthracis, B. thuringiensis, B. globigii compare qPCR and Cultivation for DL for P22 from fomites, from air and from water. Conduct aerosol release experiments to
assess Markov chain particle model Year 2 Criteria for Surrogates document Decay constants (K values) for BAC in water, fomites, aerosols Selection and assessment of a surrogate for B. anthracis Development of an algorithm for detection limit and risk Assessment of quantum dots as a surrogate
Year 2 Conduct dispersion studies of MS-2/PRD1 surrogates in water distribution system at the Water Village to aid model development Establish prediction models using artificial neural networks based on experimental data and EPAnet Anticipated Products Improved standard operating procedure for sampling Set of methods criteria and algorithms for addressing the interpretation of a negative Models for air/surface/hand risks Models for microbial transport in water distribution systems
This research was supported by funding from the Office of Research and Sponsored Programs at the University of Wisconsin-Eau Claire. Figure 1: Young adults' and middle-aged adults' reasons for maintaining their opposite-sex friendship.
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