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Title: INVESTIGATION OF POSSIBLE DYNAMIC INTERACTION OF DFIGS OF DIFFERENT CAPACITY EXISTING IN THE SAME WIND FARM
Creator: He, Fan
Date: 2011-12, 2011-12
Description: This paper explores the possibility of dynamic interaction between DFIGs of different capacity in a grid connected and islanding mode wind...
Show moreThis paper explores the possibility of dynamic interaction between DFIGs of different capacity in a grid connected and islanding mode wind farm. The modeling of DFIG is presented in the paper. The case of adding 5 MW DFIGs to a wind farm with existing 1.5 MW DFIGs is considered. Grid-connected scenario is considered regarding the connection of the units. Moreover, step-up wind speed, noisy wind speed and fault at infinite bus will be introduced as disturbances to examine the possible dynamic interaction. Simulation using MATLAB and Simulink has been used to investigate all cases. To further justify the simulation results, a series of modal small perturbation analysis is also conducted.
M.S. in Electrical Engineering, December 2011
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Title: VITREOSCILLA HEMOGLOBIN AS A STRATEGY TO ENHANCE BIODESULFURIZATION IN RHODOCOCCUS IGTS8
Creator: Bai, Nan
Date: 2014, 2014-05
Description: The bacterium Rhodococcus sp. IGTS8 contains the dsz operon encoding enzymes for the 4S pathway, which enables it to use dibenzothiophene (DBT...
Show moreThe bacterium Rhodococcus sp. IGTS8 contains the dsz operon encoding enzymes for the 4S pathway, which enables it to use dibenzothiophene (DBT), an organic sulfur containing molecule found in petroleum, as the sole source of sulfur for its metabolism. The gene vgb from Vitreoscilla encoding hemoglobin (VHb) has been widely studied and is used for improving the usefulness of a large number of heterologous hosts, like prokaryotes, lower eukaryotes and even higher plants. We produced the engineered strain IGTS8[pRESX-vgb] in which vgb was introduced into Rhodococcus sp. IGTS8. We measured the growth and the ability of desulfurization of DBT for this transformed strain (compared to the untransformed host) under both high and low aeration conditions. From CO-difference spectra, we found that VHb was successfully expressed in this transformant and the expression level was similar to that in certain other heterologous hosts. The transformant had much greater growth than untransformed IGTS8, cultured under both high and low aeration in CDM with DBT as the only sulfur source (the transformed strain outgrew the untransformed strain by about 380 % under high aeration and 68 % under low aeration). Unfortunately, we found that the color of the product from reaction of the Gibbs reagent with the final metabolite of DBT produced by the transformant was not blue. This did not allow us to directly compare the desulfurization abilities of the transformant and the untransformed strain. We did another experiment to prove that IGTS8[pRESX-vgb] still used DBT as its sole source of sulfur by culturing this transformant in CDM without DBT. IGTS8[pRESX-vgb] cannot grow in CDM without DBT. One possible explanation for this result is that the final product of the 4S pathway in the transformant may be converted to a form other ix than 2-HBP. In any case, the much better growth of the transformant compared to that of the untransformed strain provides indirect evidence that VHb does enhance biodesulfurization.
M.S. in Biology, May 2014
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Title: SURVIVAL AND SANITIZER RESISTANCE OF SALMONELLA ENTERICA ENTERITIDIS ON SHELL EGGS
Creator: Vogan, Jill Ann
Date: 2011-05-01, 2011-05
Description: The Gram negative bacterium Salmonella sp. is the most common cause of gastroenteritis in the United States and abroad. Its life cycle...
Show moreThe Gram negative bacterium Salmonella sp. is the most common cause of gastroenteritis in the United States and abroad. Its life cycle persists when the bacteria is picked up from the environment and ingested by a host animal. The bacteria adhere to the host’s small intestine and penetrate into the sub-epithelial tissue where it causes diarrhea and vomiting. The bacteria redeposit into the environment via the aforementioned route; thus, repeating the cycle. Salmonella can infect a variety of hosts and different serotypes vary in severity. In addition to the disease causing infections of some host animals such as birds and reptiles provide a reservoir for Salmonella. Reservoir hosts can carry and transmit the bacterium without showing any signs or symptoms of infection. The avian host can pick up the bacteria, by ingestion of contaminated food and water, and deposit it onto the surface or inside the egg. Salmonellosis is then transmitted to human by consumption of contaminated eggs. Salmonella enterica serotype Enteritidis is the most common serotype associated with contaminated chicken eggs. Salmonella Enteritidis inoculated onto the surface of whole chicken eggs was able to survive for at least two hours post inoculation. The rate of cell death on the shell surface increased steadily for the first 40 minutes of drying and tapered through the two hour end point. The death rate increase may have correlated with drying time on the shell surface. Further, the bacteria were able to attach to the shell within 10 minutes of incubation. Morphological examination of cells surviving on egg shells showed collapsing of the surface when dried for 30 minutes. When allowed to dry on the egg shell surface for two hours, Salmonella was able to survive sanitization with either 200 ppm hypochlorite or quaternary ammonium based sanitizer. Interestingly, a more vigorous recovery method was required to remove bacterial cells surviving on the shell surface post sanitization indicating that the sanitizers caused increased attachment.
M.S. in Biology, May 2011
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Title: Capital Design: The Role of Design in Institutional Capital Allocation
Creator: Ostapchuk, Jordan
Date: 2024
Description: There is a paradox within the $100 trillion institutional investment industry: the more choices an institutional investor has, the more...
Show moreThere is a paradox within the $100 trillion institutional investment industry: the more choices an institutional investor has, the more challenging it becomes to make investment decisions. This paradox is significant because capital is one of the most transformational elements of the 21st century, driven by financialization, universal ownership, and increasing systemic risks. The direction of capital flows significantly influences the approach to addressing climate change, aging populations, and the transition to sustainable energy, in addition to supporting the essential physical and social infrastructure supported by institutional capital. This research proposes and substantiates a novel hypothesis: design can significantly influence capital allocation in institutional investment contexts. Through an institutional case study, expert interviews, workshops with master’s level design students, and systems-informed reflective practice, this research identifies asset classes as an important and changeable lens through which institutions engage with the future. It explores how these asset classes shape choices in the capital allocation process and identifies eight design capabilities particularly suited for institutional investment contexts. In doing so, it introduces a framework termed Capital Design. This framework illustrates how design can influence institutional capital allocation by integrating these design capabilities with investment tools through informational lenses within a choice/knowledge map. As a result, Capital Design offers an innovative approach for investors and investees to reorient toward emergent asset categories that directly meet the most urgent societal needs.
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Title: Evaluation of the Native Microbiota and Comparative Analysis of a Known Cronobacter Sakazakii and a Newly Isolated Bacillus Cereus Strain in Powdered Infant Formula
Creator: Patil, Sonali Prashant
Date: 2024
Description: There have been numerous reports of Powdered Infant Formula (PIF) recalls and outbreaks due to the absence of a kill step in the post...
Show moreThere have been numerous reports of Powdered Infant Formula (PIF) recalls and outbreaks due to the absence of a kill step in the post-pasteurization processing, improper handling pre and post processing and/or reconstitution, and lack of effective sanitization and cleaning of the food contact surfaces in the manufacturing facilities. The objectives of this present study were to 1) survey and identify background microflora in commercial PIF products through microbiological analysis, 16S rRNA, and whole genome sequencing (WGS); 2) compare the survival rate of a known Cronobacter sakazakii and a newly isolated Bacillus cereus DFPST-SP1 in PIF under a humidity level of 33 ± 3% over a period of 28 d; 3) examine the relative resistance of these two strains to thermal treatments at temperatures 40, 70, and 100 °C followed by storage at room temperature (RT) for 30 min; and 4) evaluate the bactericidal effect of 70% ethanol on the two artificially deposited bacterial strains on stainless steel (SS) and plastic coupons. Three biological trials were conducted for each study. To determine whether the increase, decrease, or difference in the bacterial populations and other parameters like water activity (aw) was statistically significant, a T-test was performed (p ≤ 0.05 was considered significant). Results of 16S rRNA sequencing revealed the presence of certain bacterial species in PIF, such as Lactococcus lactis, B. cereus, Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica, etc. distributed across a relative abundance of >25%, <25%, and ≤3%. After the enrichment and isolation as per Bacteriological Analytical Manual (BAM), C. sakazakii or S. enterica were not detected, while colonies exhibiting a blue-green appearance resembling Listeria spp. and certain Bacillus spp. were subjected to WGS for species-level identification. The assembly_1 from formulation 1 was confirmed as B. cereus sequence type 2255 and was renamed as B. cereus DFPST-SP1 in the contribution of this thesis work. The storage study conducted on PIF inoculated with C. sakazakii and B. cereus DFPST-SP1 at 33% RH showed that there was 0.25-0.27 log CFU/g reduction towards the end of 28 d, but no significant difference was observed between the two strains. The thermal challenge study revealed that the newly isolated B. cereus strain and C. sakazakii used in this study were highly thermotolerant. Based on the sanitizer challenge study, 70% ethanol was significantly more effective in reducing populations of C. sakazakii as compared to B. cereus. Moreover, higher log reductions of C. sakazakii 587 populations on stainless steel coupons compared to plastic coupons were observed, indicating that bacteria adhere more tightly to plastic surfaces than stainless steel (SS). Overall, the findings of this study shed new light on bolstering the safety standards of PIF and highlight the need for improved cleaning and sanitization procedures within manufacturing facilities in order to ensure the safety of reconstituted PIF, thereby enhancing public health, particularly infants and neonates.
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Title: Three Essays on the Internet Economy
Creator: Sun, Yidan
Date: 2024
Description: In an era of digital platforms, the integrity and visibility of consumer reviews, the dynamics of digital advertising markets, and the role of...
Show moreIn an era of digital platforms, the integrity and visibility of consumer reviews, the dynamics of digital advertising markets, and the role of software development kits (SDKs) emerge as pivotal elements shaping user experiences and platform economics. My research spans three distinct but interconnected domains: the impact of safety reviews on Airbnb, the effects of privacy protections on digital advertising markets, and the significance of SDK releases in the evolution of Apple's iOS app market. We find that critical reviews concerning the safety of an Airbnb listing's vicinity influence guest bookings negatively and, therefore, could boost platform revenues if such reviews were obscured, highlighting a misalignment between consumer interests and platform revenue objectives. This effect is more pronounced in low-income and minority neighborhoods, suggesting a nuanced impact on different community segments. In the digital advertising sector, we identify that data frictions disproportionately harm small publishers, especially when associated with smaller ad intermediaries, underscoring the vulnerability of niche players to market and regulatory changes. Lastly, our analysis of the iOS app market reveals the instrumental role of SDK releases in fostering the app ecosystem's growth, independent of the expanding iPhone user base. Together, these findings underscore the complex interplay between consumer feedback, technological advancements, and market dynamics in digital environments, urging a balanced approach that safeguards consumer interests while fostering innovation and equitable market practices.
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Title: HIGH PRESSURE GAS FILLED RF CAVITY BEAM TEST AT THE FERMILAB MUCOOL TEST AREA
Creator: Freemire, Ben
Date: 2013, 2013-05
Description: The high energy physics community is continually looking to push the limits with respect to the energy and luminosity of particle accelerators...
Show moreThe high energy physics community is continually looking to push the limits with respect to the energy and luminosity of particle accelerators. In the realm of leptons, only electron colliders have been built to date. Compared to hadrons, electrons lose a large amount of energy when accelerated in a ring through synchrotron radiation. A solution to this problem is to build long, straight accelerators for electrons, which has been done with great success. With a new generation of lepton colliders being conceived, building longer, more powerful accelerators is not the most enticing option. Muons have been proposed as an alternative particle to electrons. Muons lose less energy to synchrotron radiation and a Muon Collider can provide luminosity within a much smaller energy range than a comparable electron collider. This allows a circular collider to be built with higher attainable energy than any present electron collider. As part of the accelerator, but separate from the collider, it would also be possible to allow the muons to decay to study neutrinos. The possibility of a high energy, high luminosity muon collider and an abundant, precise source of neutrinos is an attractive one. The technological challenges of building a muon accelerator are many and diverse. Because the muon is an unstable particle, a muon beam must be cooled and accelerated to the desired energy within a short amount of time. This requirement places strict requisites on the type of acceleration and focusing that can be used. Muons are generated as tertiary beams with a huge phase space, so strong magnetic fields are required to capture and focus them. Radio frequency (RF) cavities are needed to capture, bunch and accelerate the muons. Unfortunately, traditional vacuum RF cavities have been shown to break down in the magnetic fields necessary for capture and focusing. To successfully operate RF cavities in strong magnetic fields, the idea of filling xv them with a high pressure gas in order to mitigate breakdown was proposed. The gas has the added benefit of providing cooling for the beam. Experiments were successfully performed using different gas species in a test cell cavity placed in a multi-Tesla magnetic field. These encouraging results lead to the necessity of a test closer to actual accelerator conditions, namely sending a beam of particles through the cavity. The electron-ion plasma created in the cavity by the beam absorbs energy and can degrade the accelerating electric field of the cavity. Electrons can recombine with hydrogen ions, however this process is slow compared to the bunch length and spacing. As electrons account for the majority of the energy loss in the cavity, their removal in a short time is highly desirable. The addition of an electronegative dopant gas can greatly decrease the lifetime of an electron in the cavity. The results of two beam tests will be presented. The experimental variables cover a wide range of gas pressure, beam intensity, and cavity electric field. Measurements in pure hydrogen of the power consumption of electrons in the cavity indicate a range of energy loss between 10−18 and 10−16 joules per RF cycle per electron. When hydrogen doped with dry air is used, measurements of the power consumption indicate an energy loss range of 10−20 to 10−18 joules per RF cycle per ion, two orders of magnitude improvement over non-doped measurements. The rate at which electrons recombine with positively charged hydrogen ions ranges from 10−7 to 10−5 cm3 s . The lifetime of electrons in a mixture of hydrogen gas and dry air has been measured from <1 ns, up to 200 ns. Finally, the ion-ion recombination rate falls between 10−8 and 10−7 cm3 s . The results extrapolated to the parameters of a Neutrino Factory and Muon Collider indicate that a high pressure gas filled RF cavity will work in a coolingchannel for either machine. A demonstration experiment is warranted to prove this technology’s validity.
PH.D in Physics, May 2013
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Title: AN ITERATIVE APPROACH TO COMBINED IMAGE REGISTRATION AND SEGMENTATION WITH APPLICATIONS TO PROSTATE CANCER IMAGING
Creator: Bukowy, John
Date: 2012-04-19, 2012-05
Description: Machine learning techniques have shown to be a viable means of analyzing medical images for tumor segmentation. Implementation of classi ers...
Show moreMachine learning techniques have shown to be a viable means of analyzing medical images for tumor segmentation. Implementation of classi ers used for tu- mor segmentation requires training data constructed from known data sets. In most applications, obtaining the training dataset requires image registration. This thesis proposes a new combined image registration-segmentation framework to be applied to prostate tumor segmentation in MR images in the future. In order to construct training sets, known pathology from histological slides must be transferred to the MR images. Both manual and automated registration techniques have been previ- ously developed to accomplish this information transfer. Automated methods provide a reproducible, measurable result; however there is still room for improvement. The focus of this thesis is on improvement of the accuracy of the training data set through an iterative approach combining automated registration and segmenta- tion. The performance of the automated method of registration improves with an increase in the number of landmarks for matching. These extra landmarks used for registration are obtained from tumor segmentation; hence the name iterative segmentation-registration. This improvement leads to more accurate data transfer between histology and MR images and hence more accurate training data. Through numerical simulations, we show that by increasing the number of landmarks, using not only anatomical features but obtained segmentation results, the quality of the train- ing data can be improved. The proposed method results in a measurable increase in registration performance which leads to improved training data and consequently improved tumor segmentation performance.
M.S. in Electrical Engineering, May 2012
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Title: SEISMIC COLLAPSE EVALUATION OF NON-DUCTILE CONCENTRICALLY BRACED FRAMES
Creator: Wen, Rou
Date: 2012-11-21, 2012-12
Description: More attentions have been paid on the Non-Ductile Concentrically Braced Frames (ND-CBFs) in low and moderate seismicity regions recently due...
Show moreMore attentions have been paid on the Non-Ductile Concentrically Braced Frames (ND-CBFs) in low and moderate seismicity regions recently due to their low ductility detailing requirements for design and construction. In this work, seismic collapse performances of two ND-CBFs are studied. One 3-story and one 9-story ND-CBF using small response modification coefficients (R=3) are designed firstly. Nonlinear finite element technologies are used to study the behaviors of local components. Practical analytical models for brace/gusset-plate assemblies and steel gravity frames are developed based on finite element simulations and engineering judgment. Three 2D structural models having increased local modeling complexity are developed for each braced frame. Nonlinear static pushover analyses on 3-story frames are conducted to get basic understandings of the damage evolution patterns and the interactions between main brittle braced frames and the steel gravity frames. Nonlinear dynamic analyses references the concepts of Incremental Dynamic Analysis are followed to investigate the seismic collapse responses of studied frames. The seismic assessments referenced the evaluation methods in FEMA P695 for ductile seismic load resisting frames through incremental dynamic analysis are carried out. Studied results show that Non-Ductile Concentrically Braced Frames would have little chance to prevent building collapse under severe ground motions. However, it seems that such buildings at least with low-to-moderate heights would have high probability of collapse prevention for up to moderate ground motions with conventional gravity framing systems used in modern steel buildings.
PH.D in Civil Engineering, December 2012
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Title: CHILD AND PARENT PSYCHOPATHOLOGY: COMBINATIONS RELATED TO THERAPY ATTENDANCE AND PROGRESS
Creator: Giannone, Carolyn D.
Date: 2012-04-30, 2012-05
Description: Disruptive behavior disorders (DBDs) are among the most common and challenging diagnoses in children. It is well documented that family...
Show moreDisruptive behavior disorders (DBDs) are among the most common and challenging diagnoses in children. It is well documented that family therapy services can provide effective treatment for DBDs, but therapy dropout rates are high. This leaves many children untreated, particularly in urban settings. Literature supports relationships between several variables and premature termination of therapy services, including child gender, child psychopathology, parent psychopathology, and perceived barriers to treatment participation. The current study aimed explore if combinations of parent and child psychopathology and their relationship related to therapy completion. Multiple imputation was utilized due to the presence of several missing data points. Results indicated that combinations did not significantly predict therapy completion. Implications of the research, limitations, and suggestions for future research are discussed.
Ph.D. in Clinical Psychology, May 2012
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Title: ASSESSMENT OF STRUCTURAL MATERIALS BY HIGH TEMPERATURE INSTRUMENTED INDENTATION
Creator: Gan, Bin
Date: 2012-12-03, 2012-12
Description: This is an ideal place for me to express my gratefulness to my Ph.D. advisor, Prof. Sammy Tin, who has offered me the financial support and...
Show moreThis is an ideal place for me to express my gratefulness to my Ph.D. advisor, Prof. Sammy Tin, who has offered me the financial support and tremendous freedom in doing research. From working with me through publications and thesis, mentoring me what constitutes a professional and high quality work, nurturing my patience, to giving me advice on how to deliver an insightful presentation, Prof. Tin puts his effort in helping me on every small step that I need to make, as I gradually become more experienced in research and start to make a few achievement along the way. I am deeply indebted to Prof. Tin’s vision, guidance and sustained support. I would like to thank Prof. Philip Nash, Prof. Sheldon Mostovoy and Prof. Sudhakar Nair for being the committee member of my thesis defense, and offering me so many invaluable suggestions. The indispensable help from Russ Janota, the faculty and staff in the MMAE department is acknowledged. The enjoyable interaction with Mengtao, Qizheng, Matt, and other TPTC friends helps me in various aspects. I would like to thank Dr. Hideyuki Murakami and Dr. Takahito Ohmura for hosting me in NIMS. The experience had broadened my horizon and tremendously enhanced my capabilities to conduct independent research. In addition, the research collaboration with Prof. Julia R. Greer and Dr. Robert Maass on freestanding Ni3Al nanoparticles is also fully acknowledged. Furthermore, I am grateful to Prof. Qiang Feng and Prof. Roman Nowak. Their constant support, encouragement, mentoring and nurturing have a profound influence on me. This thesis is dedicated to my beloved parents, Jinlong Gan and Yuxiang Lai, who have built the fortitude into my mind. I also thank my sisters, Liping Gan and Lihong Gan, for their sustained support. Their love and understanding enable me to have a peaceful mind that makes this study possible. I also feel grateful to the deep love and endless patience from Xiaomo Li and the support from her parents.
PH.D in Materials Science and Engineering, December 2012
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Title: BLOCK COPOLYMER BASED MICELLE FOR EFFICIENT IMMUNOSENSING
Creator: Li, Ying
Date: 2012-11-26, 2012-12
Description: This thesis demonstrates the formation of micelles from a block copolymer and the application in establishing the micelle based immunosensing...
Show moreThis thesis demonstrates the formation of micelles from a block copolymer and the application in establishing the micelle based immunosensing system. The utilization of polymeric micelle as probe container and antibody carrier increases the probe to antibody ratio, which is expected to leads to better detection efficiency. The substrate used in the immunosensing is a porous 0.45 μm PVDF membrane which allows the stable immobilization of proteins. Tetraphenylporphyrin, a hydrophobic fluorescent dye, was chosen as the probe encapsulated in micelles. The block copolymer is a self synthesized α-carboxyl-ω-hydroxyl terminated Poly(ethylene oxide)-Polycaprolactone with carboxyl group on the hydrophilic end, permitting the conjugation of antibody to the micelle surface. We choose mouse IgG and its antibody anti-IgG as the pair of protein conjugates to demonstrate the immunoassay. So far, the detection limit of mouse IgG is 1.5 μg/ml (10-8 M) in this immunosensing system, which is expected to improve by modifying the system.
M.S. in Chemistry, December 2012
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Title: TOWARDS THE OPTIMAL CONFIGURATION OF USING SSDS UNDER HYBRID PARALLEL I/O AND STORAGE SYSTEMS
Creator: Feng, Bo
Date: 2014, 2014-05
Description: The performance gap between computing devices and storage devices is con- tinuously getting larger during the past a few decades. This issue...
Show moreThe performance gap between computing devices and storage devices is con- tinuously getting larger during the past a few decades. This issue incurs many I/O problems even in the eld of supercomputing. On one hand, the computing facilities grow very fast as well as the supercomputers are getting more powerful. In addition, the traditional storage devices, such as hard disk drives (HDD) fail to catch up the paces of this growth. On the other hand, applications, from both industries and sciences, are becoming data-intensive, meaning that I/O is highly demanded. Newly emerging non-volatile memory (NVM), such as ash-based solid state drives (SSD), becomes popular in both consuming and enterprise markets. Datacen- ters and supercomputing centers already glimpse this transition and are getting to deploy SSDs in their I/O systems but SSDs still have monetary problems compared to HDDs. Substantial work has been done using SSDs to accelerate I/O and storage systems. However, to the best of our knowledge, there remain some fundamental questions to be addressed, such as what type of storage con guration is suitable to HDD-SSD heterogeneity. Therefore, in this study, we built a high performance hybrid parallel I/O and storage simulator to simulate these con gurations. We also imple- mented an algorithm to approach an optimal con guration using SSDs under parallel I/O and storage systems. This methodology consists of tracing users' applications, analyzing users' requirements including hardware properties, and generating the con- guration suggestions. The experiments show its delity with the minimal error rate is 2% and practical scalability up to 256 processes. The result of this study can help system designers to either optimize current system or predict larger scale design of parallel systems in the future.
M.S. in Computer Science, May 2014
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Title: DYSFUNCTION OF BONE-MARROW-DERIVED MACROPHAGES IN GDX KNOCKOUT MICE
Creator: Bonomo, Raiza Rafael
Date: 2016, 2016-05
Description: Macrophages are cells of the immune system responsible for clearing up the organism, removing damaged and dead cells, pathogens and other...
Show moreMacrophages are cells of the immune system responsible for clearing up the organism, removing damaged and dead cells, pathogens and other foreign substances. They remove and destroy these compounds by a process called phagocytosis, in which the macrophages recognize what is to be destroyed, engulf it and digest it in the lysosome. The phagocytosis mechanism requires special cytoskeleton configurations formed by actin branches that allow the engulfment of substances into the cells. The cytoskeleton structures formed by actin branching are also known to be necessary during the macrophage migration towards its target. Our group has shown that the small cytosolic GdX protein has an important role in the actin filament branching. Therefore, the aim of this study is to analyze the migration ability and the phagocytosis potential of wild-type (WT) and GdX knockout macrophages (KO). Bone marrow cells from mice were isolated and cultured in presence of Macrophage Colony-Stimulating Factor (MCSF) to induce cell differentiation into macrophages. The bone marrow derived macrophages were then subjected to phagocytosis and migration assays. The results from the phagocytosis assay indicated no significant difference in the percentage of cells capable of internalizing the beads or in the amount of engulfed beads between WT and KO macrophages. However, the results from the migration assay suggested a decrease in the migration ability in GdX KO cells when compared to WT macrophages. Therefore,our results imply that the lack of GdX may cause macrophage dysfunction.
M.S. in Cellular and Molecular Biology, May 2016
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Title: RECONFIGURABLE ULTRASONIC SIGNAL PROCESSING SYSTEM SOLUTION BASED ON ZYNQ PLATFORM
Creator: Wang, Boyang
Date: 2015, 2015-05
Description: Ultrasonic systems are widely used in industrial and medical diagnostics ap- plications. However, an ultrasonic system has very strict...
Show moreUltrasonic systems are widely used in industrial and medical diagnostics ap- plications. However, an ultrasonic system has very strict requirements on signal capturing and processing speed because of the high frequency of the target signal. The objective of this thesis was to design an ultrasonic system including signal capturing and processing on Zynq System-On-Chip (SoC). Zynq SoC is a new technology from Xilinx which integrates both dual core ARM processors and FPGA on the same chip. This not only allows for hardware and software co-design, but also enables the I/O extensions on Zynq from FPGA. An Analog Front End (AFE) is used to gener- ate, transmit, receive, and amplify the ultrasonic signal. The AFE is controlled by a Zynq processor via Serial Peripheral Interface (SPI) and several separate control lines from General Purpose I/O(GPIO). A high speed Analog to Digital Converter (ADC) is used in the system to capture the high speed ultrasonic echo received by AFE. The ADC which is controlled through SPI, communicates with the Zynq processor by Direct Memory Access (DMA). Besides hardware platform con guration, Discrete Wavelet Transform (DWT) based compression algorithm was implemented and optimized using different methods in order to find out the best solution for realizing on the Zynq SoC. Initially, MATLAB was used to explore and verify the algorithm. Then the algorithm was implemented in hardware using VHDL language, and in soft-ware using C++. Furthermore, the compression algorithm was implemented in Open Computer Language (OpenCL) using hardware and software co-design method.
M.S. in Electrical Engineering, May 2015
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Title: CHEMICAL INACTIVATION OF RICIN ON FOOD CONTACT SURFACES
Creator: Aluri, Bharat
Date: 2011-08, 2011-07
Description: Ricin is a glycoprotein which can be easily extracted from the seeds of the castor bean plant. Ricin has potential for being used as a...
Show moreRicin is a glycoprotein which can be easily extracted from the seeds of the castor bean plant. Ricin has potential for being used as a biological weapon since it is highly toxic, relatively easy to isolate and purify and can be disseminated as a food contaminant. Thus in the case deliberate contamination event with ricin in a food processing facility, remediation of the food-contact surfaces must be done safely and effectively. The objectives of this project were to 1) identify cleaning/sanitizing treatments that result in inactivation of ricin on food contact surfaces in the absence and presence of different classes of food matrices (high fat and high starch), and 2) evaluate glucose oxidase as a surrogate for ricin in chemical inactivation studies. Ricin dissolved in PBS or mixed with a slurry of peanut butter or pancake mix was treated with different classes of detergents (phosphoric acid-based, chlorinated alkaline-based) and a sanitizer (peroxy acid-based) used to clean and sanitize food-contact surfaces. A commercially available ELISA kit was used to detect ricin after chemical treatments. Of the cleaning solutions evaluated, the phosphoric acid-based detergent was the least effective at reducing ricin detection after exposure to the cleaning chemical. In contrast, chlorinated alkaline detergent was the most effective cleaning solution for chemically inactivating ricin. The half-lives for inactivation of ricin on coupons (without food matrices) exposed to 0.5, 2 and 5% chlorinated alkaline detergent were 2.38 ± 0.25, 0.48 ± 0.05 and <0.1 min, respectively, and half-live values for inactivation of ricin in solution were 3.05 ± 0.33, 0.36 ± 0.04 and <0.1 min, respectively. The half-lives for inactivation of ricin on coupons (without food matrices) treated with 0.1, 0.5 and 1% peroxyacid-based sanitizer were 4.28 ± 0.44, 0.45 ix ± 0.05 and 0.13 ± 0.01 min, respectively, and half-live values for inactivation of ricin in solution were 6.09 ± 0.70, 0.34 ± 0.03 and 0.12 ± 0.01 min, respectively. Although no significant difference was found for ricin stability in solution vs. on coupons, in the presence of food matrices, ricin on coupons was significantly more stable than ricin in the absence of food residue. Overall, the results from this study indicated that significantly (p<0.05) higher cleaning solution concentrations were needed to inactivate the toxin in the presence of food matrices. Initial studies aimed at the evaluation of glucose oxidase as a surrogate for ricin in chemical inactivation studies indicated that the enzyme demonstrates similar susceptibility to inactivation in the presence of chemical sanitizers (sodium hypochlorite, peroxy acetic acid) as ricin. More work is needed to validate the results found in this lab-scale study with experiments conducted in a pilot-scale operation and to determine if loss of ricin activity after chemical inactivation studies also corresponds to loss in biological activity of toxin.
M.S. in Food Safety and Technology, July 2011
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Title: CHANGES OF ZEBRAFISH BEHAVIORAL RESPONSES TO ODORANTS BY OLFACTORY IMPRINTING AND LEARNING
Creator: Deng, Xin
Date: 2014, 2014-12
Description: This study reports the improved behavioral responses to odorants due to olfactory imprinting and learning. Learning is a process thereby an...
Show moreThis study reports the improved behavioral responses to odorants due to olfactory imprinting and learning. Learning is a process thereby an individual obtains the information from the environment and the retained information facilitates the subsequent reactions to the same or related information. Olfactory imprinting is a special form of learning in that it occurs in a specific stage of life such as development, and the learned information has a life long influence on animal behavior or physiology when animals encounter the same stimuli later in their life. Olfactory imprinting is an important physical process for many species. Studies in our laboratory have shown that zebrafish can be imprinted by amino acids and bile acids. Here, I studied the influence of olfactory imprinting and learning on olfactory detection sensitivity of zebrafish using behavioral tests. The experimental zebrafish included the following groups: the BA group, imprinted by two bile acids, deoxycholic acid and taurocholic acid (TCA); the AA group, imprinted by two amino acids, L-arginine and L-cysteine, and the control group without odorant stimuli. Odorant exposure for imprinting was completed on 40 days post-fertilization and behavioral tests were conducted in adult fish of one year old. TCA and lithocholic acid (LCA) were used in the adult fish behavioral tests. My results showed that zebrafish from the BA group had significant lower detection thresholds to both TCA and LCA compared with the corresponding detection thresholds in the control group of zebrafish. In contrast, the AA group of fish did not show lower detection threshold to TCA compared with the control fish. The results indicated that imprinting can increase the sensitivity of BA fish to bile acids, while imprinting of amino acids did not improve the sensitivity of the AA fish to bile acids. Learning tests were conducted in my study because the data indicated that learning might also be responsible for the lowered detection thresholds in the BA and control groups due to repeated exposure to TCA in behavioral tests. Age matched naive zebrafish were used in behavioral tests from low concentration to high concentration of TCA. Then the behavioral tests were conducted in the opposite direction, from high to low concentrations.The detection threshold obtained in the former experiments was one log unit higher than that from the later experiments. Thus, it appears that learning can also increase the sensitivity of zebrafish to bile acids. Taken together, my data indicate that the improved sensitivity to TCA in the BA group might result from a combination of both olfactory imprinting and learning.
M.S. in Biology, December 2014
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Title: Efforts to Obtain Desulfurization Competent Cultures from Environmental Samples with Increased Desulfurization Activity
Creator: Davaadelger, Batzaya
Date: 2011-04-18, 2011-05
Description: In this study, environmental samples were collected from different places to obtain various desulfurization competent cultures with increased...
Show moreIn this study, environmental samples were collected from different places to obtain various desulfurization competent cultures with increased desulfurization activity. In order to obtain the cultures the soil samples were inoculated in enriched medium and minimal medium containing DBT as the sole source of sulfur. The cultures grown in minimal medium with DBT were transferred multiple times with increasing temperatures, where as the cultures grown in enriched media were grown only one cycle at 37 degrees. After a certain growth period the cells were isolated and DNA was extracted. Efforts to amplify dsz genes from the obtained cultures with universal dszABC primers were mostly unsuccessful. DNA from bacterial strains isolated from the environmental samples were amplified with universal primers and amplicons were cloned. Samples #2, #6, #17, #21, #32 were amplified successfully but sequencing analyses showed little homology with dszABC genes. DNA from samples #32*, 32*Y and 32*W was isolated with Power Soil kit and PCR analysis showed a 3 kb amplicon. Sequencing analyses, however, showed less homology with dszABC and revealed homology instead with proteins such as those involved in Fe/S biogenesis and thiol:disulphide interchange. In addition, alternate universal primers were designed and PCR analyses were made with R .erythropolis IGTS8 and sample #32*. Alternate primer combination #3 (A1 and C1) and combination #8 (B1 and C2) amplified expected bands with IGTS8 DNA. Combination #8 amplified a 1 kb band from sample #32* DNA. Cultures #32*, #32*Y and #32*W were selected due to their ability to grow in minimal medium with DBT as high as 55 ˚C for multiple transfers. These isolated cultures from a soil sample from the Chicago area are able to catabolize dibenzothiophene (DBT) to 2-hydroxybiphenyl (2-HBP), which was detected by the Gibbs assay.
M.S. in Biology, May 2011
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Title: THE TRANSCRIPTIONAL RESPONSE OF ARTIFICIALLY-INOCULATED LISTERIA MONOCYTOGENES DURING THE MANUFACTURE OF UNPASTEURIZED GOUDA CHEESE
Creator: Carstens, Christina K.
Date: 2017, 2017-05
Description: Listeriosis outbreaks indicate that L. monocytogenes contamination is an issue for various food types, such as unpasteurized (raw) cheese....
Show moreListeriosis outbreaks indicate that L. monocytogenes contamination is an issue for various food types, such as unpasteurized (raw) cheese. Current regulation prevents the interstate sale and distribution of raw cheese and mandates a ≥60 day aging period at ≥2˚C to ensure product safety; yet studies demonstrate that pathogens can persist during aging. Environmental stress can alter the transcriptomic profiles of pathogens; however, these surveys are rarely conducted in food matrices. This study aimed to assess the transcriptomic profiles of L. monocytogenes strain F2365 during environmental stressors inherent throughout cheesemaking. First, quantitative polymerase chain reaction (qPCR) was used to monitor transcription levels of nine L. monocytogenes genes involved in virulence, stress response, energy transport, and metabolism during osmotic stress (11% NaCl) and varying temperature/time (5˚C 24 h, 25˚C 24 h, 38˚C 30 min) conditions in Brain Heart Infusion (BHI) broth, raw milk, and pasteurized milk. Generally, the genes prfA, lmo1381, lmo0963, and lmo1875 were down-regulated, whereas the genes lmo1864, lmo0914, lmo0348, lmo1428, and lmo1264 were up-regulated. Virulence gene, prfA, was most down-regulated when L. monocytogenes was grown in raw milk with salt at 25˚C (4774.72±838.14 fold; relative to 24 h growth at 37˚C). The stress response gene lmo0914, encoding σB, was most up-regulated when L. monocytogenes was grown in BHI at 25˚C with salt (14.61±7.72 fold). Additionally, transcription levels of the nine genes were assessed at points during the laboratory-scale manufacture of Gouda cheese made with raw milk artificially-inoculated with L. monocytogenes via qPCR. Similar differential regulation for both prfA and lmo0914 in L. monocytogenes was observed during cheesemaking. The gene lmo1864, encoding a putative pore-forming hemolysin, was up-regulated throughout the cheesemaking process, but was most up-regulated after stirring the curd (449.81±432.53 fold). Ultimately, these results indicate that the lmo1864 gene may play a role in L. monocytogenes survival during cheesemaking. Methods developed in this study can be used to assess the risk of L. monocytogenes, not only during cheesemaking, but during the ≥60-day aging process. Overall, these results contribute to the understanding of L. monocytogenes survival mechanisms during the cheesemaking process.
M.S. in Food Safety and Technology, May 2017
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Title: LISTERIA MONOCYTOGENES SURVIVAL AND GROWTH IN FLAVORED MILKSHAKES MADE FROM NATURALLY-AND ARTIFICIALLY-CONTAMINATED ICE CREAM
Creator: Bathija, Vriddi Mahesh
Date: 2016, 2016-12
Description: Listeria monocytogenes is the causative agent of the disease listeriosis and was implicated in a multistate foodborne outbreak associated with...
Show moreListeria monocytogenes is the causative agent of the disease listeriosis and was implicated in a multistate foodborne outbreak associated with ice cream spread over four years from 2010 to 2014 in Kansas, Oklahoma, Texas and Arizona. Ten illnesses were reported during the course of this outbreak, resulting in 100% hospitalization and a mortality rate of 33%; the individuals who died in the outbreak had consumed milkshakes made with the contaminated ice cream. The ice cream was found to be contaminated uniformly at 10 MPN/g. This study assessed the growth kinetics of L. monocytogenes in milkshakes made with naturally- and artificially-contaminated ice cream, and with or without flavoring agents. Artificial-contamination of ice cream samples included inoculation with a cocktail of rifampicin-resistant L. monocytogenes into the middle of the product using a wide-orifice pipet tip. Milkshake were prepared with or without strawberry, chocolate, or mint flavoring, using the recipe associated with the healthcare facility where the illnesses occurred. Milkshakes were stored in sterile plastic cups at 10ºC and an asymmetric (3 tubes of 100ml, 5 tubes of 10 ml, 8 tubes of 1ml and 8 tubes of 0.1ml sampling scheme) most probable number (MPN) enumeration was conducted after 0, 12, 24, 48, 72, 96 and 144 h. The Baranyi model was used to model L. monocytogenes growth rates, maximum populations, and lag phases. Compared to milkshakes made with no flavoring agents, the milkshakes with flavoring resulted in decreased growth rates for L. monocytogenes for both contamination states; the lowest growth rate of the pathogen was observed in strawberry flavored milkshakes made from artificially-contaminated ice cream (0.029 log CFU/ml per hour). Chocolate and mint flavorings resulted in significantly (P < 0.05) longer lag phases for both natural (68.2 and 83.0 h) and artificial-contamination (47.7 and 54.2 h, respectively). The highest maximum population (5.79 log CFU/ml) was achieved by L. monocytogenes in naturallycontaminated milkshakes without any flavoring agent. Since challenge studies often depend on the artificial contamination of a food product, this study evaluated the differences between artificial and natural contamination of L. monocytogenes in milkshakes. The data obtained can be used for risk assessment purposes.
M.S. in Food Safety and Technology, December 2016
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