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SYNERGISTIC EFFECT OF FATTY ACIDS AND NISIN IN INHIBITING PERSISTER AND BIOFILM OF LISTERIA MONOCYTOGENES
Title
SYNERGISTIC EFFECT OF FATTY ACIDS AND NISIN IN INHIBITING PERSISTER AND BIOFILM OF LISTERIA MONOCYTOGENES
Creator
Zhou, Jiacheng
Date
2019
Description
A foodborne pathogen Listeria monocytogenes causes a life-threatening listeriosis in humans after eating contaminated food. The FDA-approved...
Show moreA foodborne pathogen Listeria monocytogenes causes a life-threatening listeriosis in humans after eating contaminated food. The FDA-approved antimicrobial peptide nisin has been used to prevent contamination of food product from Gram-positive pathogens including L. monocytogenes. However, the formation of biofilms and persisters (i.e., metabolically dormant bacterial population) has resulted in the failure of nisin treatment. Fatty acids, which have been known to exhibit antimicrobial activities, are widely used for therapeutics, food preservation, and agriculture. Previously, we found that two fatty acid compounds lauric acids and N-tridecanoic acids are effective in inhibiting biofilms and persister formation of Gram-negative pathogens. In this study, we investigate whether the fatty acid treatment in combination with nisin promotes inactivation of L. monocytogenes, especially biofilms and persisters. The fatty acid-only treatment reduced the level of biofilms and persisters, while nisin-only treatment resulted in the development of resistant population of L. monocytogenes ATCC19115 strain. However, the co-treatment of the fatty acid and nisin synergistically enhanced the killing of L. monocytogenes by significantly decreasing the number of survived cells and inhibiting biofilms. These results are particularly important in improving food safety in that the food-grade fatty acids can be applied to repress the occurrence of resistant mechanisms of foodborne pathogens by inhibiting biofilm and persister cell formation.
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PROCESS DESIGN FOR SMART GRID COORDINATED IGCC POWER PLANT
Title
PROCESS DESIGN FOR SMART GRID COORDINATED IGCC POWER PLANT
Creator
Garcia Fracaro, Sofia Belen
Date
2019
Description
The current scientific consensus is that changes in greenhouse gas emissions will have wide-ranging effects on the natural environment as well...
Show moreThe current scientific consensus is that changes in greenhouse gas emissions will have wide-ranging effects on the natural environment as well as on human society and world economies. Cutting green house gas emissions could be achieved by switching the majority of power production to renewable sources, like wind and solar. However, the intermittent nature of renewable sources will require special attention when integrating into the electric power system. The notion of a smart grid is to introduce new dispatch capable sources as well as provide mechanisms for consumers to be responsive to power availability. One way a smart grid communicates its objectives is through the price of electricity. Economic Model Predictive Control (EMPC) can utilize forecasts of electricity prices to determine operating policies for dispatch capable generators and flexible consumers. While EMPC in the context of variable electricity prices can reduce costs (or increase the revenue), operational flexibility will usually require equipment upgrade, and add to the capital cost of the system. In this thesis an Integrated Gasification Combined Cycle (IGCC) will be used to illustrate potential dispatch capabilities, the benefits of EMPC based operation, and the challenges associated with process design in the context of smart grid coordinated operation. First it is assumed that dispatch enabling equipment is available. While EMPC can provide an increase in the revenue during plant operation, it is not amenable to the equipment design problem. While the method of ELOC can be used for integrated process design and control, we must first show that ELOC performs similar to EMPC and that it can serve as a surrogate. Finally, the ELOC based equipment design problem is formulated, which optimizes with respect to operating as well as capital costs.
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MODELING OF MAMMALIAN CELL CULTURE
Title
MODELING OF MAMMALIAN CELL CULTURE
Creator
Jackson, Robert David
Date
2019
Description
This work uses two different techniques for modeling mammalian cell culture: Differential Equation (DE) based Modeling and Agent-Based...
Show moreThis work uses two different techniques for modeling mammalian cell culture: Differential Equation (DE) based Modeling and Agent-Based Modeling (ABM). The development of both models was done in free open-source software instead of the traditional software that requires the purchase of licenses. The DE model was developed in Python and can predict total, viable, and dead cell densities, glucose, lactate, glutamine, ammonia, and product titer. To expand on the detail level capabilities of previous DE models it has added temperature, pH, and dissolved oxygen dependence. The ABM can predict viable cell density, glucose, lactate, and the distribution of the three experimentally detectable cell cycle phases G1G0, S, and G2M. The ABM was developed for high-performance computing to improve on a previous ABM and allow for running at a hundred-fold smaller run-time with a much higher capacity for the amount of agents that can be simulated.
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SEPARATING NOBLE GASES SUCH AS KRYPTON AND XENON FROM NUCLEAR POWER PLANTS OFF-GAS USING DD3R ZEOLITIC MEMBRANES: A COMPUTATIONAL MOLECULAR DYNAMICS STUDY
Title
SEPARATING NOBLE GASES SUCH AS KRYPTON AND XENON FROM NUCLEAR POWER PLANTS OFF-GAS USING DD3R ZEOLITIC MEMBRANES: A COMPUTATIONAL MOLECULAR DYNAMICS STUDY
Creator
BASHMMAKH, BANDAR JAMAL S.
Date
2021
Description
Noble gas fission products generated within nuclear power reactors, such as Kr and Xe, are currently discharged into the atmosphere. This...
Show moreNoble gas fission products generated within nuclear power reactors, such as Kr and Xe, are currently discharged into the atmosphere. This practice has a major economic drawback because of the high value associated with some of these gases. Zeolites, nanoporous materials suitable for gas separation processes, have become of major interest due to the potentially high selectivity for such separations. We have used nonequilibrium molecular dynamics to investigate the separation performance of DD3R framework zeolitic membranes (using LAMMPS software package) for such separations. Our studies have shown that the DD3R membrane shows promise for high selectivity ratios of Kr over Xe. The effects of pressure, temperature and pure vs. mixture gas feed conditions are studied in this work to understand at the molecular level the mechanisms of these (Kr/Xe) separations. MD runs show an agreement with most experimental trends in the permeation of Kr/Xe pure and mixed gases using DD3R zeolite with high separation factor, despite the absence of Xe complete permeation through the membrane because of MD timescale limitation, signaling much slower diffusion in comparison to Kr which is a desired trend in looking for high separation factors.
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High Energy High Power Primary Lithium Batteries with Graphite Fluoride and Functionalized Boron Nitride Cathodes
Title
High Energy High Power Primary Lithium Batteries with Graphite Fluoride and Functionalized Boron Nitride Cathodes
Creator
Huo, Haobin
Date
2022
Description
The present Thesis concerns with the creation of high energy and high power batteries through the utilization of functionalized 2D materials...
Show moreThe present Thesis concerns with the creation of high energy and high power batteries through the utilization of functionalized 2D materials such as graphite fluoride (CFx) and functionalized boron nitride (FBN). The recent literature of Li-CFx batteries brings forward several methods to fabricate high energy and high power batteries. These methods include nano-architecture and porosity design, boron doping, electrolyte additives etc. The resulting batteries are capable to achieve 800-1000 Wh/kg energy density at a power density of 60-70 kW/kg. Our method is capable to achieve the same performance in a much simpler way by the application of a binder that also functions as an effective inhibitor of the growth of LiF crystals. Since LiF is the discharge product of Li-CFx batteries, it typically clogs the pores of the cathode and avoids fast discharge. Methods that increase the power density of Li-CFx batteries typically focus on the amorphization/dissolution of LiF to allow for a fast Li ion diffusion. Our solution using the effective binder appears to be well suited for a scalable production of high energy and high power Li-CFx batteries through a very small modification of existing production lines. Such high energy and high power batteries are needed for the electrification of aircraft such as unmanned aerial vehicles (UAVs), vertical take-off and landing planes (VTOLs), passenger airplanes and pulsed power sources. While Li-CFx batteries are not rechargeable this is not a problem for the above mentioned applications as current rechargeable batteries cannot provide the required energy and power densities.Li-FBN batteries may provide a rechargeable alternative to Li-CFx when fully developed. In the present thesis, we have demonstrated Li-FBN batteries with similar discharge plateaus and approximately half the capacity of Li-CFx batteries. Our Li-FBN batteries are also rechargeable to a much greater extent than Li-CFx.
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