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Title: TRANSFER MECHANISM AND TRANSCRIPTOMIC PROFILING OF SALMONELLA IN FRESH-CUT FRUITS
Creator: Chen, Ruixi
Date: 2018, 2018-05
Description: Salmonella has been recognized as an increasing concern for food safety of fresh fruits because of their constant involvement in associated...
Show moreSalmonella has been recognized as an increasing concern for food safety of fresh fruits because of their constant involvement in associated foodborne outbreaks. However, knowledge is relatively limited about the transfer pattern of this particular pathogen from contaminated to uncontaminated fruits, nor do we know about the molecular mechanisms incorporated by it to address the environment of fresh fruits. In this study, we investigated the transfer mechanism of Salmonella enterica serovars Newport and Typhimurium between fresh gala apples and cantaloupes, respectively, via consecutive fresh cuttings and the subsequent survival of the strains in juice and cube fruit products under 4oC for up to 7 days. We also used RNA-seq and bioinformatics approaches to explore the transcriptome of Salmonella Newport in cantaloupe in comparison with 0.1% BPW (control group). Our results demonstrated fresh cutting as a practical way for bacterial transfer from contaminated to up to 4 uncontaminated fruits, and the transfer rate decreased drastically as the number of fresh cuts increased. The relative distribution of Salmonella cells in the 1st un-inoculated cantaloupe sample was significantly higher than the corresponding gala apple sample (p ≤0.05), while the transfer rate to the following un-inoculated samples in the cantaloupe group was visibly lower than the gala apple group. In general, cantaloupe, rather than gala apple, was capable to at least maintain a constant level of bacterial population during the 7 days storage at 4oC, with juice sample being even more supportive than cube sample (p ≤0.05). Moreover, Salmonella Typhimurium had a better adaptation in cantaloupe environment than Salmonella Newport. According to the results of transcriptome analysis, metabolism activities were promoted for essential nutrient requirements including carbon, energy, nitrogen, phosphorus, iron and zinc comparing to the control group, while suppressed for others such as lipid and fatty acids (FDR ≤0.05, |log2 FoldChange| ≥1). The differential regulation of the corresponding genes of the biological processes was possibly achieved in a time much less than 1 hour.
M.S. in Food Safety and Technology, May 2018
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Title: COMPUTATIONAL STUDIES OF HEAT TRANSFER IN TURBULENT WAVY CHANNEL FLOWS
Creator: Dzubur, Amar
Date: 2018, 2018-05
Description: Heat transfer is studied in fully-developed turbulent flows through channels with various geometries using Direct Numerical Simulations (DNS)....
Show moreHeat transfer is studied in fully-developed turbulent flows through channels with various geometries using Direct Numerical Simulations (DNS). Channels where a sinusoidal wave is mapped along the wall in either the streamwise direction or spanwise direction are studied, and comparisons to a simple channel with flat walls (rectangular channel) are provided. The fluid flow velocities fi elds, and pressure fi elds are analyzed along with the vorticity generated in the flow, and are utilized in tandem with the Nusselt number calculated along the heat transfer boundaries, to derive a clearer description of the heat transfer performance of the various geometries. The geometries that have a sinusoidal wave mapped along the spanwise direction and not along the streamwise direction showed the poorest heat transfer performance, as exhibited by the lowest average Nusselt number. The performance of two channels, with an in-phase and out of phase sinusoidal wave mapped along the streamwise direction exhibited heat transfer performance signifi cantly higher than that shown by the rectangular channel, which served as baseline. The heat transfer differences can be largely attributed to the vorticity generation and superior fluid mixing that is generated by the periodic streamwise mapped sinusoid. Streamwise sinusoidal channels exhibit Nusselt numbers that are more than three times greater than the spanwise mapped sinusoid, and almost three times greater than that of the rectangular channel. It is shown that the difference among an in-phase and out of phase wave mapping exists, but is found to be minimal. Further exploration regarding potential geometries with various phase shifts, non-rounded corners, and longer simulation times would be beneficial.
M.S. in Mechanical and Aerospace Engineering, May 2018
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Title: IDENTIFICATION OF SURROGATE MICROORGANISMS AND USE OF PERACETIC ACID IN EXTENDED SHELF LIFE REFRIGERATED HIGH-ACID JUICE AND BEVERAGE PROCESSING
Creator: Stachler, Donna
Date: 2018, 2018-05
Description: The present study aim is to identify a surrogate microorganism that could be used in validation studies for Extended Shelf Life (ESL) chilled...
Show moreThe present study aim is to identify a surrogate microorganism that could be used in validation studies for Extended Shelf Life (ESL) chilled juice beverages with Peracetic Acid (PAA) in the processing system. Historically, Bacillus atrophaeus has been the primary surrogate, especially for aseptic systems with PAA; nevertheless this organism may be overly conservative for ESL processing that doesn’t have as high thermal temperature or PAA concentration. A baseline study was conducted to determine PAA resistance for B. atrophaeus spores. After being heat shocked at 82°C (179.6°F) for 13 minutes, 106 colony forming units per milliliters (CFU/mL) spores were spot inoculated and dried on stainless steel coupons. Then submerged in 200 ppm and 500 ppm VigorOx LS-15® PAA concentration, in two minute increments up to ten minute exposure time, at 50°C (122°F). The PAA reaction was halted and remaining spores were plated on Dextrose Tryptone Agar supplemented with yeast extract (DTA+ye), then incubated at 30°C (86°F) for 24 h. B. atrophaeus is PAA resistant and at least three log CFU/mL reduction was achieved for both concentrations at ten min exposure time. The next phase of the study was the selection of 15 different Bacillus species to conduct similar PAA resistance testing (with exposure time reduced to two and four minutes and additional 100 ppm of PAA) in an effort to evaluate which had the largest potential to be studied further. The three selected were B. pumilus, B. licheniformis (A) and B. licheniformis (B), due to high PAA resistance and similarity to B. atrophaeus inactivation. The three microorganisms were then studied against spoilage microorganisms (Aspergillus niger and Saccharomyces cerevisiae) and pathogenic microorganisms (Listeria monocytogenes, Salmonella species, and Escherichia coli O157:H7) at 200 ppm and 500 ppm PAA concentration. It was concluded that B. licheniformis (B) was the best overall surrogate with half log CFU/mL reduction at one minute and 200 ppm, as it was more resistant to PAA than A. niger and Salmonella. At 500 ppm PAA concentration B. atrophaeus continues to be best surrogate. Further studies, including testing to verify the behavior of B. licheniformis, as a surrogate, are recommended.
M.S. in Food Processing Engineering, May 2018
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Title: IDENTIFYING E AND F LAYER IONOSPHERIC IRREGULARITIES WITH A SCINTILLATION AURORAL GPS ARRAY
Creator: Sreenivash, Vaishnavi
Date: 2018, 2018-05
Description: The Scintillation Auroral GPS Array (SAGA), comprising six kilometer-spaced receivers located in Poker Flat, Alaska, has been deployed for...
Show moreThe Scintillation Auroral GPS Array (SAGA), comprising six kilometer-spaced receivers located in Poker Flat, Alaska, has been deployed for four years to study high latitude scintillation effects on L1 and L2C frequency Global Positioning System (GPS) signals. These scintillations disrupt the GPS signals received on the earth, affecting navigation services. Scintillation is associated with the variations in plasma densities known as irregularities, present in the ionosphere. Research on scintillation has been done from the past using different instruments and techniques, and for multiple purposes. One important prior effort is automated detection of the scintillation of L1 frequency GPS signals. Other successful research includes estimating the drift velocity of irregularities, anisotropy, height and thickness of the scattering layer. It is important to check before studying the properties of irregularities whether the sensors can detect the scintillations happening in the E or F region. In other words, it is essential to check that the sensors are sensitive not only to F region scintillations but also to the E region scintillations. The purpose of this work is to identify the ionospheric region, E or F, which is responsible for the scintillation on the L1 and L2C GPS signals. The scintillations of these GPS signals are further classified based on the type of scintillation i.e., phase scintillation and amplitude scintillation. The scintillation events are categorized as amplitude, phase, or both on L1 or L2C frequency occurring in the E or F region. Using the automated scintillation detection routine, a complete list of phase and amplitude scintillations on all days for both the frequencies L1/L2C in the years 2014 and 2015 is created. The highly scintillating days for 2014 and 2015 are sorted and the irregularities layer associated with these scintillation events are identified. The Poker Flat Incoherent Scatter Radar (PFISR) and All Sky Camera images are used to develop the process of identifying the ionospheric region. The electron density from PFISR is assumed to be an essential parameter to determine the E/F layer irregularities. The All Sky Camera provides the red auroral brightness and the green auroral brightness, where red aurora implies F region and the green aurora implies E region. A summary of a subset of the scintillation events occurring on the highly scintillating days in 2014 and 2015 is provided through this work. It is found that phase scintillation is occurring more predominantly in the high latitudes than the amplitude scintillation. A number of these are attributed to E and F region irregularities. In future, the scintillation events obtained from this work will be used to study the E and F layers irregularities and properties in detail.
M.S. in Mechanical and Aerospace Engineering, May 2018
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Title: DESIGN FLOW OF ADVANCED ENCRYPTION STANDARD HARDWARE ACCELERATION USING ZYNQ SYSTEM-aN-CHIP
Creator: Rarick, Samuel
Date: 2018, 2018-05
Description: The Advanced Encryption Standard (AES) is a symmetric encryption algorithm used by the United States government to protect sensitive...
Show moreThe Advanced Encryption Standard (AES) is a symmetric encryption algorithm used by the United States government to protect sensitive information. In this study, three implementations of a 256-bit AES algorithm are presented to accelerate the computational elements of the algorithm: a low-area, high-performance, and hybrid implementation. The three implementations were developed for the ZedBoard development board which contains a Zynq-7000 SoC. The Zynq-7000 SoC contains both a processing system (dual-core ARM processor) and programmable logic (Xilinx-7 FPGA). This relation between hardware and software of the Zynq-7000 SoC was exploited by implementing the key schedule algorithm of AES on the dual-core ARM processor, while implementing the AES encryption core on the Xilinx-7 FPGA. A high-level synthesis design flow was followed for its flexibility and reduction of development time. The result for latency is about a 2.5 times acceleration for the low-area implementation, a 12 times acceleration for the hybrid implementation, and a 44 times acceleration for the high-performance implementation. For the area results, the high-performance implementation can theoretically fit 13 encryption cores on the ZedBoard, while both the low-area and hybrid implementations can theoretically fit 35 encryption cores on the ZedBoard.
M.S. in Computer Engineering, May 2018
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Title: A MICROSCOPICALLY INTACT GASTROINTESTINAL ANASTOMOSIS: METHODS OF CONSTRUCTION AND MEANS OF ASSESSMENT
Creator: Hedberg, H. Mason
Date: 2018, 2018-05
Description: Recent research reveals that healing of anastamotic wounds can be impaired by the adherence of gut bacteria to exposed collagen. Sutures and...
Show moreRecent research reveals that healing of anastamotic wounds can be impaired by the adherence of gut bacteria to exposed collagen. Sutures and staples create a network of microscopic channels along the inverted cut bowel edge which may promote bacteria-mediated anastomotic breakdown. Techniques that preserve microscopic tissue integrity may be key to preventing clinical anastomotic leaks. Our objective was to develop a sensitive assay to determine anastomotic integrity across various techniques including single-layer hand-sewn, stapled, adhesive and bipolar. All anastomoses were performed in an end-to- end fashion between segments of porcine small intestine; intact bowel served as a control. Prototypes were designed to facilitate technically consistent bipolar and adhesive anastomoses between everted bowel ends. The anastomotic lumen was placed in series with a low-flow, low-pressure circuit of concentrated fluorescein solution. Normal saline filled a chamber surrounding the anastomosis; extraluminal solution was periodically sampled for analysis. Fluorescein concentration was quantified with spectrophotometry. Intact controls and adhesive anastomoses showed minimal increase in fluorescein concentration. Over fifteen minutes the adhesive anastomoses leaked less than bipolar (p=0.05), stapled (p<0.01), and hand-sewn (p=0.12) anastamoses. Sewn anastomoses had the highest leak variance, accounting for the lack of significance. Adhesive anastomoses improved microscopic integrity to fluorescein compared to all other techniques. The immediate next phase will include revising bipolar and adhesive prototypes, improving statistical power, and using a bacterial culture in lieu of fluorescein. Focusing on techniques that produce the most biologically intact anastomoses has the potential to prevent clinical anastomotic leaks.
M.S. in Biomedical Engineering, May 2018
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Title: CAREGIVERS OF TRANSITION-AGE YOUTH WITH INTELLECTUAL AND DEVELOPMENTAL DISABILITIES: THE ROLE OF SELF-COMPASSION BETWEEN STIGMA AND PSYCHOLOGICAL ADJUSTMENT
Creator: Ivins-lukse, Melissa Nicole
Date: 2018, 2018-05
Description: Family caregivers of youth with intellectual and developmental disabilities (IDDs) often serve as life long caregivers for their family...
Show moreFamily caregivers of youth with intellectual and developmental disabilities (IDDs) often serve as life long caregivers for their family members. Little is known about the experiences of these caregivers during their youths’ transitional phase between adolescence and adulthood, particularly with regard to their experiences of selfcompassion, courtesy stigma, and wellbeing. As courtesy stigma (stigma experienced as a result of a person’s connection to a stigmatized individual) is associated with a variety of negative outcomes for caregivers, it is essential to identify protective factors to buffer caregivers from these effects. The present study surveyed 130 family caregivers of transition age youth with IDDs and tested positive aspects (“self-kindness”) and negative aspects (“self-coldness”) of self-compassion as potential mediators between courtesy stigma and caregiver psychosocial outcomes. Self-coldness partially mediated the relationship between courtesy stigma and caregiver life satisfaction (effect = -.13, CI = -.28 to -.03), while self-kindness did not. Both self-kindness (effect = .10, CI = .02 to .21) and self-coldness (effect = .17, CI = .07 to .30) partially mediated the relationship between courtesy stigma and caregiver depressive symptoms. Overall self-compassion (positive and negative aspects combined) was tested as a moderator of the relationships between courtesy stigma and caregiver psychosocial outcomes; no significant interactions were observed. Findings suggest self-compassion offers some protective effects from courtesy stigma for caregivers. Future research should seek to explore potential differences in these relationships according to caregiver gender or care recipient diagnostic group.
M.S. in Psychology, May 2018
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Title: FACTOR STRUCTURE OF THE EMPOWERMENT SCALE IN MILITARY FAMILIES
Creator: Kereszturi, Katherine
Date: 2018, 2018-05
Description: Military families are vulnerable to many difficulties, including not just physical and mental health issues, but also financial, social, and...
Show moreMilitary families are vulnerable to many difficulties, including not just physical and mental health issues, but also financial, social, and occupational hardships. As such, they may experience disempowerment, or feelings of inadequacy to handle the myriad problems which they must confront. To create greater access to resources and provide necessary supports for this population, it is important that they feel empowered to advocate on their own behalves. Increased empowerment may also help military families to benefit more from programs and services already in place. Additionally, research indicates that empowerment is its own reward; those who feel empowered tend to have better mental and physical health outcomes and are more capable of solving their own problems (as opposed to relying on helping professionals). While empowerment has been studied in the rehabilitation psychology literature in other populations, it has yet to be studied in military families. The current study is an analysis of the factor structure of the Empowerment Scale in a sample of veterans and their family members participating in a peer-to-peer guided services program. Identifying the factor structure of the Empowerment Scale in this sample will aid future researchers in using the scale to study empowerment as both a process and an outcome in psychological studies looking at military families. Though previous studies have established a five factor model of empowerment, the current study suggests a four factor model with the following four factors identified: 1) self-esteem and self-efficacy, 2) autonomy, 3) community activism, and 4) anger and authority. Implications of the four factor model in the understanding of empowerment among military families are explored.
M.S. in Psychology, May 2018
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Title: SYNTHESIS OF NEW CATHODE AND ANODE STRUCTURES FOR LITHIUM-SULFUR BATTERIES
Creator: Lin, Yiwei
Date: 2018, 2018-05
Description: One of the greatest technological success stories in recent years has been that of the development and commercialization of the Li-ion battery...
Show moreOne of the greatest technological success stories in recent years has been that of the development and commercialization of the Li-ion battery (LIB) technology. It has been predicted that the silicon anode technology will be the next evolution in LIBs, due to its potential to enable cheaper, higher capacity batteries. To attain its immense storage capacity, the silicon particles in the anode must expand to accommodate the lithium ions. In this expansion lies the technological challenge facing further development of silicon anode technology. The consequences of the expansion can be simplified into the following issues: swelling and rupture, loss of mechanical stability due to pulverization of the electrode, and cell drying. In this thesis work, we have designed a novel nanostructured anode material that will address some of the key issues preventing commercial applicability of silicon anode. We have also designed a novel nanostructured cathode material that will store high percentage of sulfur and exhibit high capacity retention. While the synthesis of these novel nanostructured materials was the primary objective, some preliminary electrochemical data have also been presented in the thesis. These two materials (lithiated silicon as the anode and sulfur as the cathode) can be combined to construct lithium-sulfur batteries (LSBs), which have potential to provide 3-5 times more energy than that of current LIBs at lower cost. Moreover, sulfur is environmentally benign and one of the most abundant elements on earth. More importantly, its low operating voltage of 2.1 V could offer safety advantages over high-voltage intercalation cathodes (>4 V) used in LIBs. Thus, realization of a practical Li-S technology can move the U.S. rapidly toward a more sustainable transportation future.
M.S. in Chemistry, May 2018
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Title: THE CHOLESTEROL LOWERING EFFECTS OF STRAWBERRY: A RANDOMIZED CONTROLLED TRIAL ESTABLISHING STRAWBERRYS' ROLE IN CARDIOVASCULAR HEALTH
Creator: Huang, Leailin
Date: 2018, 2018-05
Description: Cardiovascular diseases (CVD) represent the principal cause of morbidity and mortality worldwide. Recent studies suggest fruit and vegetable...
Show moreCardiovascular diseases (CVD) represent the principal cause of morbidity and mortality worldwide. Recent studies suggest fruit and vegetable consumption, especially berries, such as strawberry, is associated with lower risk of developing CVD. However, clinical trials demonstrating the specific risk factors affected by strawberry intake are not conclusive at present. Therefore, the objectives of this study were to assess strawberry intake on lipid and lipoprotein profile, endothelial function and blood pressure in individuals with moderate hypercholesterolemia. Thirty-four subjects (n=34) contributed to this analysis. This study was a randomized, double-blinded, placebo-controlled, cross-over, 12 week intervention design. Subjects were randomized to 1 of 2 study sequences in a 1:1 ratio. Sequence 1 was strawberry beverage, followed by 4 week wash out and crossover to placebo beverage. Sequence 2 was placebo beverage, followed by 4 week wash out and crossover to strawberry beverage. Subjects incorporated the strawberry or placebo beverage into their diet regularly (twice per day). Beverages were made from freeze-dried strawberries or a sensory and energy matched placebo powder. Strawberry containing beverages contained the equivalent of ~1.75 servings of fresh strawberries/beverage. Blood collection, anthropometrics, blood pressure and flow-mediated vasodilation (FMD) of the brachial artery were measured at baseline (week 0) and week 4, week 8 and week 12. Study findings showed that strawberry supplementation had overall treatment effects on increasing %FMD and decreasing systolic blood pressure compared to placebo (p=0.0096 and p=0.048, respectively). The 4 weeks strawberry supplementation did not significantly change anthropometric measures, lipid profile, glucose, insulin, and hs-CRP compared to placebo (p>0.05, all). Thus, strawberries may improve endothelial function and blood pressure, independent of other metabolic alterations, and may be considered an important fruit to include in a heart healthy diet in overweight or obese subjects with moderate hypercholesterolemia.
M.S. in Food Safety and Technology, May 2018
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Title: INITIAL VALIDATION OF AN OBSERVATIONAL MEASURE OF TEMPERAMENT IN PRESCHOOL-AGED CHILDREN
Creator: Plumb, Nora
Date: 2018, 2018-05
Description: Literature has shown that temperament predicts a range of childhood outcomes, including social competence, academic performance, and empathic...
Show moreLiterature has shown that temperament predicts a range of childhood outcomes, including social competence, academic performance, and empathic responsiveness. Temperament also has been consistently shown to be a risk factor for psychopathology (e.g., externalizing disorders, conduct problems, anxiety, and depression). Although there is general agreement on the definition of temperament, there are still aspects of this construct that are disputed (e.g., the specific traits involved and the degree to which they are stable across development). Moreover, researchers also have developed different strategies to assess this construct, specifically parent-report and direct observation, both of which have their limitations. Despite these limitations, very few measures temperament measures utilize ecologically valid observations in naturalistic settings. The purpose of this study was threefold. The first aim was to examine the construct validity of a newly-developed behavioral observation measure of temperament through confirmatory factor analysis (CFA). The second aim was to determine if the measure was invariant across age and gender. Finally, the third aim was to assess the measures’ convergent and predictive validity. This measure was administered to 796 children across three ages (i.e.,ages 4, 5, and 6). Results from the CFAs revealed that a four-factor structure was the best fit to the data at age 4, therefore supporting configural invariance across gender for that age group. Invariance testing also showed that the measure demonstrated metric, but not scalar, invariance across gender at age 4. Finally, this study found evidence for both convergent and predictive validity for this measure. Directions for future research are also discussed.
M.S. in Psychology, May 2018
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Title: SURVIVAL OF LISTERIA MONOCYTOGENES AND ESCHERICHIA COLI O157:H7 DURING AGING OF GOUDA CHEESE MADE USING UNPASTEURIZED MILK
Creator: Natarajan, Vidya
Date: 2018, 2018-05
Description: The FDA code of federal regulations states that cheeses made using unpasteurized milk must be aged for a period of at least 60 days to...
Show moreThe FDA code of federal regulations states that cheeses made using unpasteurized milk must be aged for a period of at least 60 days to minimize the inherent risks associated with unpasteurized milk. However, there have been several foodborne outbreaks associated with 60-day aged semi-soft cheeses made using unpasteurized milk, specifically Gouda cheese. In this study, Gouda cheese was manufactured using unpasteurized milk artificially-inoculated with Listeria monocytogenes (1 or 3 log CFU/mL) and Escherichia coli O157:H7 (1 log CFU/mL). The Gouda cheese was pressed, brined, waxed, and aged at 10°C for 90 (for the 1 log CFU/mL) or 150 (for the 3 log CFU/mL) days. Samples were assessed during cheese manufacture and aging for survival of the pathogen as well as for the population dynamics of the native microflora including Enterobacteriaceae, yeast and mold, lactic acid bacteria, and mesophilic bacteria. In addition, cheese samples during aging were also analyzed for property characteristics including salt and moisture content, fat in solid content, pH, and water activity. Results determined that the population levels of both pathogens significantly increased during manufacture. During aging of the Gouda cheese, E. coli O157:H7 was capable of survival only until 49 days and was henceforth not detected via enrichment. For L. monocytogenes, pathogen populations were 2.07±0.12 log and 1.26±0.00 log CFU/g at 60 and 90 days of aging, respectively, for the 1 log CFU/mL initial inoculation level. Compared to day 60 (2.31±0.92 log CFU/g) of aging, the population of L. monocytogenes for the Gouda cheese made with the 3 log CFU/mL initial inoculation level was significantly higher (p<0.05) on both 90 and 150 d of aging (4.62±0.25 and 6.00±0.72 log CFU/g, respectively). During aging, the populations of lactic acid and mesophilic bacterial were significantly higher than other microflora categories. The population of yeast and mold displayed an increasing trend in population, whereas Enterobacteriaceae populations were highly unsteady. Increases in lactic acid bacterial populations were accompanied by decreases in pH and pathogen populations. These results indicate that the characteristics of Gouda cheese and the native microflora population may play a pivotal role in survival and growth of pathogens. Overall, this study suggests that the current 60-day aging regulation, while sufficient to control E. coli O157:H7, may not be suitable to control the risk of L. monocytogenes in Gouda cheese.The population of yeast and mold displayed an increasing trend in population, whereas Enterobacteriaceae populations were highly unsteady. Increases in lactic acid bacterial populations were accompanied by decreases in pH and pathogen populations. These results indicate that the characteristics of Gouda cheese and the native microflora population may play a pivotal role in survival and growth of pathogens. Overall, this study suggests that the current 60-day aging regulation, while sufficient to control E. coli O157:H7, may not be suitable to control the risk of L. monocytogenes in Gouda cheese.
M.S.in Food Safety and Technology, May 2018
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Title: MACHINE LEARNING METHODS FOR PREDICTING GLOBAL AND LOCAL CRIME IN AN URBAN AREA
Creator: Navarro Comes, Eric
Date: 2018, 2018-05
Description: In recent years there has been growing interest in development of computer methods that can model and predict crime events for crime...
Show moreIn recent years there has been growing interest in development of computer methods that can model and predict crime events for crime prevention in law enforcement agencies. A popular example is the creation of crime density maps which are used to provide early-warning information about potential hotspots of crime in an urban area. One important aspect of predictive policing is to identify the time and place of likely crime occurrence so as to prevent future crime events. The ability to make accurate, timely predictions can be particularly important for optimizing police resource allocation in an urban area. This thesis focuses on developing machine learning techniques in crime analysis and prevention for predicting the overall crime trend in an urban area, as well as the likelihood of crime occurrence in a given local area during a time period. By using crime data extracted from the Citizen and Law Enforcement Analysis and Reporting (CLEAR) system in the city of Chicago, we demonstrate that state-of-the-art learning algorithms can achieve improved prediction accuracy over traditional methods based on time series models. We then study prediction techniques for determining the likelihood of crime occurrence at a specific local area during a given time window. We demonstrate these techniques in the operational framework of the Strategic Decision Support Centers (SDSCs) in the Chicago Police Department, where only a small number (up to six) surveillance cameras can be monitored simultaneously at any given time in a single district. We apply prediction techniques to select those cameras that most likely have crime events happening within their viewsheds during a determined time window, thereby maximizing the crime monitoring efficiency. Using these models, we can achieve higher accuracy than the methods based on local crime density alone.
M.S. in Electrical Engineering, May 2018
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Title: THE ASSOCIATION BETWEEN DEPRESSIVE SYMPTOM FACTORS AND CANNABIS USE
Creator: Miner, Jacob L.
Date: 2018, 2018-05
Description: Substance use and mood disorders are the most common co-occurring psychiatric disorders, with cannabis use and depression being the most...
Show moreSubstance use and mood disorders are the most common co-occurring psychiatric disorders, with cannabis use and depression being the most prevalent. Despite the growing body of evidence examining the relationship between depression and cannabis use, the association is still not well understood. The purpose of the present study was to determine if depressive symptom type (i.e., somatic vs. cognitive) was differentially associated with severity of past month cannabis use. Due to inconsistencies in the literature, no a priori hypothesis was made. Data for this study were obtained from the 2015 national survey sample sponsored by the Substance Abuse and Mental Health Services Administration (SAMHSA). Depression variables used for the analysis consisted of the 9 symptoms related to a diagnosis of Major Depressive in the DSM-IV. Confirmatory Factor Analyses indicated that the best fitting measurement models was a two-factor model of depression, with a 4-symptom somatic factor and a 5-symptom cognitive factor. Results of the full structural equation model indicated that neither somatic nor cognitive symptom factors significantly predicted past month cannabis use. There is a need for a better understanding of the way depressive symptoms are associated with cannabis use.
M.S. in Psychology, May 2018
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Title: TARGETED AND SUSTAINED DELIVERY OF POLYPHOSPHATE FOR SUPPRESSION OF BACTERIAL COLLAGENASE AND POST-SURGICAL INTESTINAL HEALING
Creator: Nichols, Dylan
Date: 2018, 2018-05
Description: Nanoparticle drug delivery holds great promise in the field of nanomedicine. Nanoparticles, containing encapsulated drugs, provide a variety...
Show moreNanoparticle drug delivery holds great promise in the field of nanomedicine. Nanoparticles, containing encapsulated drugs, provide a variety of advantages for administration of therapeutic factors including controlled and sustained drug release and site-specific targeting thereby improving therapeutic efficacy. At the forefront of modern medicine is the onset of understanding how an individual’s microbiome may impact their health and how to avoid upsetting this sometimes delicate but often essential ecosystem. The human gastrointestinal tract is subject to a variety of physiological perturbations as a result of disease or surgical interventions that lead to major disturbances in gut microbial ecology. Furthermore, administration of antibiotics to address these issues have been shown to exacerbate the intestinal dysbiosis and create local cues that shift the composition and function of the normal microbiota to a state in which certain strains become dominant and pathogenic. Furthermore, antibiotic administration to treat intestinal infections during surgery or disease invariably kill off the normal flora and contribute to the proliferation and antibiotic resistance of virulent pathogenic strains. Thus, approaches focused on targeted delivery of therapeutic compounds to the intestinal epithelium that suppress pathogenic expression (i.e. virulence and tissue degrading activity) while allowing commensal bacteria to proliferate normally would be highly advantageous. Previous studies in the Alverdy laboratory at the University of Chicago have demonstrated that phosphate becomes depleted in the intestinal tract following surgical injury and is a major “cue” that triggers bacterial virulence. Furthermore, phosphate or polyphosphate supplementation has been shown to prevent in vitro bacterial transition to virulence and to prevent impaired intestinal healing (anastomotic leak) with oral polyphosphate administration in mouse models of surgical anastomosis with intestinal inoculation. In this thesis we propose the use of polyphosphate loaded nanoparticles (NP-PPi) as a drug delivery approach to attenuate the expression of pathogens identified to produce elevated levels of the tissue destroying enzyme collagenase, resulting in intestinal healing impairment. A previously developed inverse miniemulsion polymerization process used for the creation of phosphate loaded poly(ethylene) glycol nanoparticles is adapted for post-loading of polyphosphate into the particles. This results in the formation of polyphosphate loaded nanoparticles (NP-PPi) with high polyphosphate concentration and in its sustained release. In vitro studies demonstrated that NP-PPi were effective at attenuating collagenase production and biofilm formation, two key markers of bacterial virulence, for clinically relevant gram-negative pathogens. Ex vivo and in vivo studies demonstrate that NP-PPi remain mucoadhesive onto intestinal explants and to the intestinal epithelium when delivered in combination with an adhesive polyethylene glycol block copolymer, PEG 15-20. Furthermore, ex vivo studies indicate that NP-PPi are effective at suppressing bacteria colonization, suggesting their potential for attenuating tissue invasion of host pathogens in vivo.
M.S. in Biomedical Engineering, May 2018
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Title: THE ROLE OF THE BAXΔ2 C-TERMINAL STRUCTURE IN CASPASE-8- MEDIATED CELL DEATH OF HUMAN COLORECTAL CARCINOMA CELLS
Creator: Nelson, Adam
Date: 2018, 2018-05
Description: BaxΔ2 is an isoform of the proapoptotic Bcl-2 family member Bax that promotes cell death via caspase-8 activation. The C-terminus of BaxΔ2 has...
Show moreBaxΔ2 is an isoform of the proapoptotic Bcl-2 family member Bax that promotes cell death via caspase-8 activation. The C-terminus of BaxΔ2 has been shown to be crucial for caspase-8 dependent cell death in colon cancer cells. However, it is unknown whether the C-terminal primary sequence or secondary structure is necessary for interaction with caspase-8. In this project, several BaxΔ2 C-terminal mutants were generated based on secondary structure predictions. Models showed that mutating Leu164 and Thr165 to Ala (LT-AA) would increase the probability of alpha helix formation, while mutating Leu164 to Pro (L-P) would decrease the probability of alpha helix formation. Expression of these mutant proteins in colon cancer HCT116 cells, showed that L164P, and not L164A/T165A, significantly impaired BaxΔ2 function. The mutant L164P proteins formed atypical aggregates, and their ability to induce cell death was also significantly decreased when compared to the wild type. These results indicate that the BaxΔ2 C-terminal tridimensional structure, and not the specific primary sequence, is critical for triggering aggregation-mediated cell death.
M.S. in Biology, May 2018
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Title: GROWTH, SURVIVAL, AND INACTIVATION OF LISTERIA MONOCYTOGENES IN HUMMUS
Creator: Mhetras, Tanvi
Date: 2018, 2018-05
Description: Listeria monocytogenes is widely spread in the environment and is the causative agent of listeriosis. L. monocytogenes can contaminate ready...
Show moreListeria monocytogenes is widely spread in the environment and is the causative agent of listeriosis. L. monocytogenes can contaminate ready-to-eat (RTE) foods such as dairy products, salad dips, sandwiches, and seafood. In recent years, various recalls of hummus products have been reported to be associated with L. monocytogenes. This study aimed to 1) assess survival of L. monocytogenes on individual dry ingredients (chickpeas and sesame seeds), 2) examine survival of the pathogen in individual wet ingredients (mashed chickpeas and tahini) of hummus; 3) to evaluate L. monocytogenes survival in complete hummus dips; and 4) to determine L. monocytogenes inactivation in hummus dip using high pressure processing (HPP). Dry hummus ingredients (chickpeas and sesame seeds) were inoculated with a cocktail of four L. monocytogenes strains and stored at relative humidity (RH) levels of 25, 45, and 75% RH at 25 C for 28 d. When inoculated at 10 log CFU/g, L. monocytogenes populations decreased significantly (P<0.05) on sesame seeds and chickpeas in the first 24 h. The pathogen was more resistant to survival on sesame seeds at each of the RH levels than on chickpeas. The lowest D-value observed for L. monocytogenes was 9.90 d on chickpeas at 45% RH, while the highest value was 35.87 d on sesame seeds at 75% RH. When inoculated onto wet ingredients of hummus (mashed chickpeas and tahini), hummus dip, and hummus made using contaminated tahini or mashed chickpeas at 2 log CFU/g, L. monocytogenes was capable of survival in tahini during 28 d storage at 10 C. In mashed chickpeas, however, the pathogen increased significantly by approximately 4 log CFU/g after 7 d and had a growth rate of 2.21±1.34 log CFU/g/d. In hummus dip, L. monocytogenes had a significantly lower growth rate (0.11±0.01 log CFU/g/d) than in the mashed chickpeas. In hummus made using contaminated mashed chickpeas, the L. monocytogenes population significantly increased by 1.16 log CFU/g after 14 d. In hummus made using contaminated tahini, L. monocytogenes was capable of surviving, but did not grow. Hummus dip was treated with HPP at 350 MPa with holding times of 60,120,180 and 240 s. The D-value for L. monocytogenes was determined to be 98.2 seconds. The results from this study will aid in determining how L. monocytogenes survives in Refrigerated RTE hummus and its individual dry and wet ingredients. The study will also help in assessing the use of HPP for inactivation of L. monocytogenes in contaminated hummus.
M.S. in Food Safety and Technology, May 2018
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Title: VERIFYING FIBERS MEET REGULATORY DEFINITIONS FOR NUTRITION FACTS LABELING: A RANDOMIZED, CONTROLLED TRIAL EVALUATING POLYDEXTROSE IN DRY FORM
Creator: Zhao, Anqi
Date: 2018, 2018-05
Description: National concern over low fiber intake in America has prompted the food industry to supplement processed foods with added fibers. The U.S....
Show moreNational concern over low fiber intake in America has prompted the food industry to supplement processed foods with added fibers. The U.S. Food and Drug Administration (FDA) proposed a new rule for Nutrition Facts labeling requiring added/functional fibers to demonstrate a physiological health benefit to be considered as dietary fiber on the Nutrition Facts label. Physiological benefits, however, can be affected by the fiber’s physiochemical properties and environment (i.e. food matrix). Polydextrose (PDX) is a synthetic polymer of glucose resistant to digestion with mixed reports regarding its contribution to producing physiological effects based on “acceptable” fiber benefits: glucose control, cholesterol lowering and laxation effect. Previously we showed that PDX does not lower postprandial glucose when added to a sugar drink (wet matrix). In the present study, we tested PDX in a dry cereal bar to determine if the dry matrix would reveal differential effects of PDX on postprandial glycemia. In a randomized, 3 h postprandial, crossover clinical trial, nineteen participants (10 male, 9 female) with a mean (± SD) age of 35.1 ± 8.5 y and BMI 25.0 ± 3.6 kg/m2 consumed a cereal bar with either 0 g or 12 g of PDX as a light breakfast on two separate occasions. Consumption of the cereal bar with 12 g of PDX significantly increased the postprandial glucose and insulin responses compared to 0 g control (p=0.02 and p=0.01, respectively). Total area under the curve (AUC) values for glucose over 3 hours was not significantly higher than control (p=0.16), but total AUC for insulin was significantly higher (p=0.03). Gastrointestinal (GI) tolerability was evaluated using scores ranked according to usual feelings of GI sensitivity. Overall, no significant changes or differences between treatments in GI tolerability were observed (p>0.05). Based on the endpoint of glycemia and the proposed FDA rule for fiber labeling, PDX would not qualify as a dietary fiber on the Nutrition Facts label.
M.S. in Food Safety and Technology, May 2018
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Title: CHARACTERIZATION OF GATE-ALL-AROUND FIELD EFFECT TRANSISTORS BASED ON BSIM-CMG MODEL
Creator: Yang, Muyu
Date: 2018, 2018-05
Description: The objective of this thesis is to analyze the characteristics of gate-all-around (GAA) field-effect-transistors (FETs) based on BSIM-CMG ...
Show moreThe objective of this thesis is to analyze the characteristics of gate-all-around (GAA) field-effect-transistors (FETs) based on BSIM-CMG (Berkeley Short-channel IGFET Model Common Multi-Gate) compact model. As devices continue scaling according to Moore’s Law, traditional planar multi-gated MOSFET cannot suppress the short-channel effects (SCE). The GAA FETs structure is a good candidate for sub-7nm technology nodes because of its’ electrostatic gate control and the ability to suppress the SCE. In this thesis, two different kinds of GAA FETs, Lateral GAA FETs (LGAA FETs) and Vertical GAA FETs (VGAA FETs), are characterized and compared with multi-gate FinFETs. The devices implemented in this thesis are all based on BSIM-CMG compact models from Berkeley BSIM Group and PTM-MG compact models from Nanoscale Integration and Modeling (NIMO) Group. In this dissertation, LGAA FETs and VGAA FETs are compared with double-gate FinFETs, triple-gate FinFETs and quadruple-gate FinFETs. Firstly, both N-type and P-type of devices are characterized for a variety of parameters to investigate their properties. Then basic logic gates, i.e. Inverter, NOR and NAND, are created based on GAA FETs and multi-gate FinFETs, and simulated for comparison. Finally, an extended datapath study was done by implementing several full adder designs, including the traditional 28T mirror adder, the 9A adder, the 13A adder, the SERF adder, the CLRCL adder, the HULPFA adder, and the ULPFA adder. Simulation results confirm that LGAA FETs and VGAA FETs have substantially smaller leakage current and dynamic power consumption but slightly increased delay when compared with traditional planar multi-gate FinFETs.comparison. Finally, an extended datapath study was done by implementing several full adder designs, including the traditional 28T mirror adder, the 9A adder, the 13A adder, the SERF adder, the CLRCL adder, the HULPFA adder, and the ULPFA adder. Simulation results confirm that LGAA FETs and VGAA FETs have substantially smaller leakage current and dynamic power consumption but slightly increased delay when compared with traditional planar multi-gate FinFETs.
M.S. in Electrical Engineering, May 2018
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Title: VARIOUS ATTACHMENT AND RECOVERY OF MS2 FROM THE CONTACT SURFACES OF GLASS AND POLYMERS
Creator: Yan, Runan
Date: 2018, 2018-05
Description: Human enteric viruses are recognized as a primary etiology for foodborne diseases in the United States. Enteric viruses are highly contagious...
Show moreHuman enteric viruses are recognized as a primary etiology for foodborne diseases in the United States. Enteric viruses are highly contagious and easily transmitted via the interaction (attachment or adhesion) with biotic or abiotic surfaces followed by extended survival and then transferred to food during food preparation. Containers and tools for handling foods are commonly manufactured of polymers. These abiotic surfaces could serve as vehicles for potential viral transmission to foods. The research objective is to evaluate factors that potentially affect virus adhesion to substrate surfaces thus altering viral disease transmission, including (i) variables of the food-contact materials (e.g., polymers and glass), and (ii) finish of food-contact surfaces (e.g., smooth or rough). The virus recovery comparison by infectivity, and the surface topography by atomic force microscopy (AFM) and profiler were employed in this study. The food-contact materials used in this study include lab-made high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), and commercial polyvinyl chloride (PVC) and two types of glass. Smooth polymer sheets were made by injection molding; and some were abraded with sand paper to produce rough surfaces. Coliphage MS2 suspension, as the inoculum, was completely air-dried first on substrate surfaces, and then cold-stored for 24 hrs at 4 °C to allow sufficient contact time between viruses and surface before the viruses were eluted and recovered. Two elution protocols were developed to accommodate different sizes of the substrates, with similar virus elution efficiency confirmed. Viruses in eluates were quantified by double agar layer plaque assay. Potential alterations in virus recovery from a substrate after surfactant sodium dodecyl sulfate (SDS) pre-treatment were also tested. Via AFM measurement, smooth substrate surfaces exhibited overall uniform nanoscale profiles, with average RMS approximately ranging from 0.4 to 4.4 nm. Rough surfaces were characterized by a profiler due to greater roughness than the upper measurement limitation of AFM (2 μm). Pinholes with an approximate average 21 nm in diameter were found in cover glass, which probably contributed to significantly lower virus recoveries (32 ± 6%, averaged from 5 trials, n = 18) than that from bottom glass (48 ± 9%, averaged from 9 trials, n = 26) where no holes were observed. For smooth polymer surfaces, the greatest virus recovery was from PP with an average of 76 ± 12% (n = 14), followed by HDPE (54 ± 6%, n = 20) and LDPE (53 ± 6%, n = 7). Interestingly, virus recoveries were always significantly lower from the corresponding rough surfaces (p < 0.001), indicating rough substrate topography could potentially serve as reservoirs for viruses. By pre-treating a thin layer of SDS at various concentrations to mask the substrate surface hydrophobicity, the virus recovery from PVC surface increased by up to 21%. These data potentially assist in selecting appropriate food-contact materials and how to construct the contact surfaces in order to eliminate similar size-foodborne viruses being trapped or retained on food-contact surfaces during cleaning or intentional removal, and thus prevent foodborne viral disease transmission.
M.S. in Food Safety and Technology, May 2018
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