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- Foodborne pathogen (2)
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Articles 1 - 8 of 8
Full-Text Articles in Physical Sciences and Mathematics
An Agent-Based Simulator For The Gastrointestinal Pathway Of Listeria Monocytogenes, Ashrafur Rahman, Ali Asgary, Daniel Munther, Aamir Fazil, Ben A. Smith, Jianhong Wu
An Agent-Based Simulator For The Gastrointestinal Pathway Of Listeria Monocytogenes, Ashrafur Rahman, Ali Asgary, Daniel Munther, Aamir Fazil, Ben A. Smith, Jianhong Wu
Mathematics and Statistics Faculty Publications
We developed an agent-based gastric simulator for a human host to illustrate the within host survival mechanisms of Listeria monocytogenes. The simulator incorporates the gastric physiology and digestion processes that are critical for pathogen survival in the stomach. Mathematical formulations for the pH dynamics, stomach emptying time, and survival probability in the presence of gastric acid are integrated in the simulator to evaluate the portion of ingested bacteria that survives in the stomach and reaches the small intestine. The parameters are estimated using in vitro data relevant to the human stomach and L. monocytogenes. The simulator predicts that 5%–29% of …
Classification Of Triples Of Lattice Polytopes With A Given Mixed Volume, Gennadiy Averkov, Christopher Borger, Ivan Soprunov
Classification Of Triples Of Lattice Polytopes With A Given Mixed Volume, Gennadiy Averkov, Christopher Borger, Ivan Soprunov
Mathematics and Statistics Faculty Publications
We present an algorithm for the classification of triples of lattice polytopes with a given mixed volumemin dimension 3. It is known that the classification can be reduced to the enumeration of so-called irreducible triples, the number of which is finite for fixed m. Following this algorithm, we enumerate all irreducible triples of normalized mixed volume up to 4 that are inclusion-maximal. This produces a classification of generic trivariate sparse polynomial systems with up to 4 solutions in the complex torus, up to monomial changes of variables. By a recent result of Esterov, this leads to a description of all …
Inequalities Between Mixed Volumes Of Convex Bodies: Volume Bounds For The Minkowski Sum, Gennadiy Averkov, Christopher Borger, Ivan Soprunov
Inequalities Between Mixed Volumes Of Convex Bodies: Volume Bounds For The Minkowski Sum, Gennadiy Averkov, Christopher Borger, Ivan Soprunov
Mathematics and Statistics Faculty Publications
n the course of classifying generic sparse polynomial systems which are solvable in radicals, Esterov recently showed that the volume of the Minkowski sum P1++Pd of d-dimensional lattice polytopes is bounded from above by a function of order O(m2d), where m is the mixed volume of the tuple (P1,,Pd). This is a consequence of the well-known Aleksandrov-Fenchel inequality. Esterov also posed the problem of determining a sharper bound. We show how additional relations between mixed volumes can be employed to improve the bound to O(md), which is asymptotically sharp. We furthermore prove a sharp exact upper bound in dimensions 2 …
Active Disturbance Rejection Control Of Torsional Plant With Unknown Frequency Harmonic Disturbance, Rafal Madonski, Momir Stanković, Sally Shao, Zhiqiang Gao, Jun Yang, Shihua Li
Active Disturbance Rejection Control Of Torsional Plant With Unknown Frequency Harmonic Disturbance, Rafal Madonski, Momir Stanković, Sally Shao, Zhiqiang Gao, Jun Yang, Shihua Li
Mathematics and Statistics Faculty Publications
In this work, a new robust control algorithm is introduced for uncertain systems with harmonic disturbances of unknown frequencies. The proposed solution works under the active disturbance rejection control (ADRC) framework and utilizes a specialized observer for sinusoidal uncertainties, aided with an on-line harmonic disturbance frequency estimator. The entire governing structure is derived in a convenient error-based domain, easily deployable in various industrial control software. The idea behind the introduced approach is general, but is conveyed here using solely a three degrees-of-freedom torsional system, which is considered a benchmark for vibration phenomenon in many mechanical systems. The efficacy of the …
Towards Enhanced Chlorine Control: Mathematical Modeling For Free Chlorine Kinetics During Fresh-Cut Carrot, Cabbage And Lettuce Washing, Parthasarathy Srinivasan, Mohammadreza Dehghan Abnavi, Anthony Sulak, Chandrasekhar R. Kothapalli, Daniel Munther
Towards Enhanced Chlorine Control: Mathematical Modeling For Free Chlorine Kinetics During Fresh-Cut Carrot, Cabbage And Lettuce Washing, Parthasarathy Srinivasan, Mohammadreza Dehghan Abnavi, Anthony Sulak, Chandrasekhar R. Kothapalli, Daniel Munther
Mathematics and Statistics Faculty Publications
In this study, we developed a novel produce-specific mechanistic model to predict free chlorine (FC) dynamics during washing of disk-cut carrots, cut cabbage, and cut iceberg lettuce, in 3 L and 50–100 L tanks, and of shredded iceberg lettuce in 3200 L pilot-plant trials. Ranges for two key parameters: β (L mg−1 min−1) the apparent reaction rate constant of FC with produce constituents, and γ, the fraction of the increase of chemical oxygen demand (COD) contributing to the reaction, were determined at the 3 L scale. For disk carrots β∈[0.05,0.09] and γ∈[0.054,0.078], for cut cabbage β∈[0.05,0.10] and γ∈[0.09,0.12], and for …
Enhancing Produce Safety: State Estimation-Based Robust Adaptive Control Of A Produce Wash System, Vahid Azimi, Daniel Munther, Mojtaba Sharifi, Patricio A. Vela
Enhancing Produce Safety: State Estimation-Based Robust Adaptive Control Of A Produce Wash System, Vahid Azimi, Daniel Munther, Mojtaba Sharifi, Patricio A. Vela
Mathematics and Statistics Faculty Publications
The rapid introduction of fresh-cut produce into a produce wash system can dramatically decrease the free chlorine (FC) concentration level in the wash water, resulting in potential widespread cross-contamination throughout the entire wash system. To minimize such contamination, a sufficient level of FC must be maintained in the wash water. This paper presents a state estimation-based robust adaptive sliding mode (RASM) control strategy for the wash system to stabilize the FC concentration level during fresh-cut iceberg lettuce washing. This feedback control law for FC dosing is suggested to provide a sufficient FC injection rate (FCIR) to the wash system in …
Formation Of Escherichia Coli O157: H7 Persister Cells In The Lettuce Phyllosphere And Application Of Differential Equation Models To Predict Their Prevalence On Lettuce Plants In The Field, Daniel S. Munther, Michelle Q. Carter, Claude V. Aldric, Renata Ivanek, Maria T. Brandl
Formation Of Escherichia Coli O157: H7 Persister Cells In The Lettuce Phyllosphere And Application Of Differential Equation Models To Predict Their Prevalence On Lettuce Plants In The Field, Daniel S. Munther, Michelle Q. Carter, Claude V. Aldric, Renata Ivanek, Maria T. Brandl
Mathematics and Statistics Faculty Publications
American Society for Microbiology. Escherichia coli O157:H7 (EcO157) infections have been recurrently associated with produce. The physiological state of EcO157 cells surviving the many stresses encountered on plants is poorly understood. EcO157 populations on plants in the field generally follow a biphasic decay in which small subpopulations survive over longer periods of time. We hypothesized that these subpopulations include persister cells, known as cells in a transient dormant state that arise through phenotypic variation in a clonal population. Using three experimental regimes (with growing, stationary at carrying capacity, and decaying populations), we measured the persister cell fractions in culturable EcO157 …
Role Of Hydrodynamic Interactions In Chemotaxis Of Bacterial Populations, Shawn D. Ryan
Role Of Hydrodynamic Interactions In Chemotaxis Of Bacterial Populations, Shawn D. Ryan
Mathematics and Statistics Faculty Publications
How bacteria sense local chemical gradients and decide to move has been a fascinating area of recent study. Chemotaxis of bacterial populations has been traditionally modeled using either individual-based models describing the motion of a single bacterium as a velocity jump process, or macroscopic PDE models that describe the evolution of the bacterial density. In these models, the hydrodynamic interaction between the bacteria is usually ignored. However, hydrodynamic interaction has been shown to induce collective bacterial motion and self-organization resulting in larger mesoscale structures. In this paper, the role of hydrodynamic interactions in bacterial chemotaxis is investigated by extending a …