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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: An Alternative Approach for the Jefferson Lab Electron-Ion Collider Ion Accelerator Complex
Creator: Martinez Marin, Jose Luis
Date: 2020
Description: An assessment by the National Academy of Sciences (NAS) of the scientific merit for a future Electron Ion Collider (EIC) in the US concluded...
Show moreAn assessment by the National Academy of Sciences (NAS) of the scientific merit for a future Electron Ion Collider (EIC) in the US concluded that such a facility would be unique in the world and enable indispensable research on current and compelling scientific questions. This assessment confirmed the recommendations of the 2015 Nuclear Science Advisory Committee (NSAC) for an EIC with highly polarized beams of electrons and ions, sufficient luminosity and sufficient, variable center-of-mass energy. Proposals were requested for a cost-effective design that uses existing accelerator infrastructure to reduce the risk; one of two major proposals submitted for consideration originated from the Thomas Jefferson National Accelerator Facility (JLab). The Jefferson Laboratory Electron-Ion Collider (JLEIC) would use the Continuous Electron Beam Accelerator Facility (CEBAF) at JLab as a full-energy electron injector. The primary accelerator challenges are twofold: producing and maintaining a high degree of polarization for both beams, and achieving high luminosity. This thesis project was part of an effort to produce an alternative, low-risk and cost- effective design for the JLEIC ion complex. The primary goal was not to find a replacement for the JLEIC ion complex design, but rather to investigate alternative options for the different components of the ion complex that could lower the overall cost, reduce its footprint, mitigate risk, and identify possible staging or future upgrades of the project. The platform for this thesis was the alternative design for the JLEIC ion complex that included (1) a more compact ion linac, (2) two staged ion boosters instead of one before injection to the collider ring, with a more compact and lower energy Pre-Booster ring as the first stage, and (3) the dual use of the electron storage ring (e-ring) as a second stage ion Large Booster.The alternative design was first investigated for medium energy (65-GeV center-of-mass), and was then upgraded following the National Academy of Sciences (NAS) review to higher energy (100-GeV center-of-mass). Developing a more cost-effective design and meeting all the requirements is challenging due to several constraints imposed on the alternative approach -- for example, the use of only room-temperature magnets for both ion boosters. There are also space limitations, the need to keep the shape and crossing angle of the ion Large Booster the same as the collider ring, ensuring reasonable length and aperture requirements for the magnets, and avoiding transition crossing for all the rings, which can cause beam dilution and instabilities.Development of both the Medium-Energy and the High-Energy options is presented. The Medium-Energy option consists of a 135 MeV injector linac, a 3 GeV octagonally-shaped Pre-Booster ring and a 11 GeV Large Booster. The High-Energy option consists of a 150 MeV (~ 40 MeV/u for Pb) injector linac, a 8 GeV (~ 2.04 GeV/u for Pb) non figure-8 Pre-Booster ring and a 40 GeV proton (~ 16 GeV/u for Pb) Large Booster, which would also serve as the electron storage ring (e-ring). The figure-8 shape of the Large Booster helps to maintain high polarization. High luminosity is achieved following a strategy to have a high bunch repetition rate of the colliding beams, very short bunch lengths, and small transverse emittances; the main concern here is to provide a lattice that is consistent with these requirements. The main results reported are the lattice design optimization and consolidation, benchmarking of the beam optics with different codes such as ELEGANT, COSY-Infinity, MAD-X, TRACE-3D, and Zgoubi, and spin resonance simulation results. Spin dynamics studies were performed for the linac and the Pre-Booster, and mechanisms to preserve the polarization are proposed. Beam formation and non-linear effects such as chromaticity, space charge, and intra-beam scattering were also studied to gain understanding of how the alternative approach could affect the baseline beam formation scheme and to ensure that the beam requirements are met through the injector chain with this alternative approach. It was shown that the polarization can be preserved through the alternative ion complex even with the more compact linac and a Pre-Booster that does not have a figure-8 shape by using a sufficiently long spin correction solenoid in the linac and a partial Siberian snake in the Pre-Booster. The baseline beam formation scheme could still be used to reach the required beam characteristics for collider injection. Cooling is not needed in the more compact Pre-Booster, and the large, higher energy booster helps to avoid space charge effects at extraction. This study has confirmed the effectiveness of the alternative approach as concerns the optics, acceleration, polarization, and beam formation. The ion injectors are sufficiently compact, and the ion Large Booster size and shape are consistent with the e-ring requirements, enabling the desired dual functionality of that machine. This work created a basis for design discussions during the JLEIC design process. The final High-Energy design for the JLEIC ion complex adopted design features that came from the alternative design studies, which were derived in part from this work—in particular, the shorter, lower-energy linac, the use of two boosters in the injection chain before the collider ring, and the ability to have only room-temperature magnets in the boosters, with superconducting magnets used only in for the collider ring.
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Title: FEARING FORGETTING? DEVELOPMENT OF A SCALE TO ASSESS ATTITUDES ABOUT DEMENTIA IN THE LAY POPULATION
Creator: Ogu, Precious N
Date: 2020
Description: Individuals with dementia show a progressive decline in cognitive functioning which results in an inability to complete activities of daily...
Show moreIndividuals with dementia show a progressive decline in cognitive functioning which results in an inability to complete activities of daily living (American Psychiatric Association, 2013). Early diagnosis of dementia is a positive prognostic indicator (World Alzheimer Report, 2011) and is widely regarded as an important pre-condition for improving dementia care (Kim et al., 2015; Vernooij-Dassen et al., 2005). However, negative attitudes and stigma towards dementia could possibly interfere with an individual’s willingness to recognize or accept the idea of themselves having the disease through label avoidance. The goal of the present study was to contribute to understanding the perception of dementia by developing a quantitatively derived and psychometrically validated measure that encompasses the positive and negative attitudes towards dementia held by people without dementia. This study also explored the potential association between negative attitudes about dementia and lack of familiarity with dementia as familiarity with individuals with mental illness is related to stigmatizing attitudes towards mental illness. These goals were achieved by a principal components analysis (PCA) of 56 modified items from extant and well-validated mental illness attitude scales (Community Attitudes to Mental Illness, CAMI, Taylor & Dear, 1981; Social Distance Scale, SDS, Link, 1986; Depression Stigma Scale, DSS, Griffiths et al., 2004). Convergent validity was assessed by examining the relationship between the final derived measure and a construct associated with negative attitudes about mental illness (Mental Retardation Attitude Inventory-Revised, MRAI-R). Discriminant validity was assessed by examining the relationship between the final measure and a construct that should be unrelated to negative attitudes about mental illness (Belief in a Just World Scale, BJW). Finally, exploratory analyses were conducted to assess if attitudes measured by the newly created scale are related to participants’ familiarity with dementia (Level of Familiarity Scale, LoFS, Corrigan et al., 2001). 400 adults with no history of dementia were recruited through Amazon’s MTurk. Participants were compensated by a credit to their Amazon account upon completion of the survey. The PCA supported 2 conceptually different (not method variance) latent components titled Negative Attitudes and Positive Attitudes. These 2 components comprise the Attitudes to Dementia Inventory (ADI). Construct validity was partially supported for each component of the ADI. Degree of familiarity with dementia was not associated with negative or positive attitudes about dementia. Overall, this study is an important contribution to dementia attitudes research. Given the identification of Negative Attitudes and Positive Attitudes have been identified as distinct dimensions of dementia attitudes, the ADI can be used to further investigate how negative reactions towards dementia might cause delays in initiating medical intervention and treatment, and also to examine whether positive attitudes provide any protections against the probable effects of negative attitudes on stigma and help-seeking behaviors. Since the early recognition and diagnosis of dementia is widely regarded as an important condition for improving dementia care (Kim et al., 2015; Vernooij-Dassen, et al., 2005), the ADI can be used to inform stigma-prevention, which hopefully translates into improved help-seeking behaviors.
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Title: GROWTH KINETICS OF SALMONELLA ENTERICA DURING REHYDRATION OF DEHYDRATED PLANT FOODS AND SUBSEQUENT STORAGE
Creator: Ren, Yuying
Date: 2020
Description: Dehydrated plant foods have low water activities and do not support the growth of pathogenic bacteria like Salmonella enterica. Once...
Show moreDehydrated plant foods have low water activities and do not support the growth of pathogenic bacteria like Salmonella enterica. Once rehydration, the water activities will increase to > 0.92, and along with their neutral pHs, plant foods may be able to support the growth of S. enterica. Therefore, product assessments are required to determine the extent to which these products support growth of S. enterica. The purpose of this study was to determine the growth kinetics of S. enterica during rehydration with 5 or 25 °C water, and subsequent storage of dehydrated potatoes, carrots, and onions at 5, 10, and 25 °C. Fresh plant foods were dehydrated at 60°C (140°F) for 24 h. Dehydrated plant foods were inoculated with 4 log CFU/g of a 4-strain cocktail of S. enterica and dried for 24 h. Samples were rehydrated using 4-volumes of 5 or 25 °C water for 24 h. During rehydration, 30 g of sample was removed and drained for 10 min. Ninety mL of BPB was added to triplicate 10-g samples. Serial dilutions of the homogenate were plated onto TSA overlaid with XLD agar for enumeration of S. enterica. After 24 h rehydration, the remaining samples were drained and stored in containers at 5, 10, and 25°C for 7 d. S. enterica was enumerated at 1, 3, 5, and 7 d. Three independent trials were conducted. Growth kinetics were determined using DMFit and data were statistically analyzed using Student’s t-test (α=0.05). Overall, the growth rates of S. enterica when 5 °C water was used for rehydration were higher than when 25 °C water was used for potatoes and carrots. The highest growth rate of S. enterica was 3.74 log CFU/g per d on potatoes, leading to a 1 log CFU/g increase in S. enterica after only 0.27 d (16 h) which occurred during storage at 25 ℃ after 5℃ water rehydration. The highest growth rate on carrots was 1.98 log CFU/g per d (requiring only 0.51 d to increase 1 log CFU/g) when rehydrated with 5℃ water and stored at 25 ℃. The growth rates were the lowest during the storage of rehydrated onions. S. enterica required 12.5 d to increase 1 log CFU/g (the growth rate was 0.61 log CFU/g per d) when the onions were rehydrated with 25 ℃ water and stored at 25 ℃. The results of this study determined that S. enterica could survive and grow in dehydrated plant foods during rehydration and storage, highlighting the need for product assessments for these types of foods.
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Title: Targeting Respiratory Pathways to Combat Persistence: Investigating the Role of Respiratory Complexes in Klebsiella Aerogenes Persister Cell Formation
Creator: Barnes, Alyssa Britney
Date: 2024
Description: Klebsiella aerogenes is a multidrug-resistant nosocomial pathogen that poses significant challenges due to its ability to form persister cells...
Show moreKlebsiella aerogenes is a multidrug-resistant nosocomial pathogen that poses significant challenges due to its ability to form persister cells that evade antibiotic treatment and contribute to chronic infections. This study explored the relationship between respiratory complexes and persister cell formation, focusing on NDH-2, NQR, and cytochrome oxidases. The research used a combination of wild-type and mutant strains, along with respiratory inhibitors and antibiotics, to identify key metabolic pathways influencing persister survival.The results revealed that NDH-2 plays a pivotal role in persister cell formation, with NDH-2 mutants demonstrating a significant reduction in persister populations over time. Comparative analysis of respiratory mutants highlighted differential reliance on oxidative phosphorylation, with NDH-2 being essential for maintaining energy metabolism during stress. In contrast, mutants lacking NQR or nuo complexes exhibited slower colony count declines, suggesting a shift to low-energy states that mimic persister characteristics. These findings emphasize the critical role of the respiratory chain, particularly NDH-2, in bacterial persistence and highlight its potential as a therapeutic target. By disrupting energy metabolism, it may be possible to eradicate persister cells and reduce the recurrence of infections caused by K. aerogenes, providing a promising avenue for combating multidrug-resistant pathogens.
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Title: Optimal Power Allocation Over Gaussian Broadcast Channels
Creator: Chen, Pengpeng
Date: 2024
Description: For Gaussian broadcast channel, the maximal capacity region can be achieved. A power assignment over Gaussian broadcast channels splits the...
Show moreFor Gaussian broadcast channel, the maximal capacity region can be achieved. A power assignment over Gaussian broadcast channels splits the power budget at the access point among all user channel pairs subject to per-channel upper bounds on the sum power, and is optimal if it maximizes the weighted sum-rate (WSR). The capacity region reaches its maximum when the weighted sum rate over Gaussian broadcast channels is maximum, making this a classic and significant problem within the wireless communication community.This thesis begins by addressing the problem of maximizing the WSR. In the single Gaussian broadcast channel, the traditional methods for computing optimal power assignment have utilized Lagrange multipliers for convex optimizations, with computational complexities ranging from $O(|U|^3)$ to $O(|U|^2 \log(|U|))$. A more recent approach has reduced this to $O(|U|^2)$. We propose a new geometric algorithm for optimal power assignment over a single Gaussian broadcast channel. This algorithm operates with linear complexity, provided all users are pre-sorted by weight or noise. Our method offers an intuitive water-filling interpretation, which subsequently allows us to develop a water-filling algorithm for optimal power assignment over parallel Gaussian broadcast channels. The complexity of this algorithm remains linear in terms of the number of user-channel pairs, assuming pre-sorted users by weight. For computing an optimal power assignment over parallel Gaussian broadcast channels, no explicit time complexity is known in the literature. Due to power constraints imposed by the base station, energy efficiency is an essential metric to evaluate the performance of these transmissions. Following the WSR optimization, we then tackle the problem of maximizing the weighted energy efficiency (WEE). In this context, a power assignment over parallel Gaussian broadcast channels involves splitting a power budget at the access point among all channel-user pairs, subject to per-channel upper bounds on the sum power. This allocation yields specific rate allocations to each channel-user pair. The WEE is defined as the ratio of the weighted sum rate to the sum-power plus a fixed positive overhead. The Max-WEE problem seeks a power assignment that maximizes the WEE. Although special variants of Max-WEE, such as those with unit weights or two users per channel, have been extensively studied, existing algorithms for these variants lack known bounds on running time. This is primarily because they rely on general-purpose methods for fractional programming.In this thesis, we derive fundamental properties and closed-form expressions for the maximum WEE. Building on these theoretical foundations, we devise a simple yet effective water-filling algorithm for solving the Max-WEE problem. Our algorithm, under the assumption that all users are pre-sorted by weight, has the linear complexity in terms of the number of channel-user pairs. Furthermore, under a mild pre-sorting condition, we develop an additional linear-complexity algorithm for the Max-WEE problem, subject to rate demand constraints.Overall, our research presents novel and efficient algorithms for power assignment over Gaussian broadcast channels, including the algorithms for maximizing the WSR, and the algorithms for maximizing the WEE. These algorithms demonstrates significant potential for practical applications in wireless communication systems. Our work offers a comprehensive solution to fundamental problems in the field and paves the way for further advancements in wireless communications.
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Title: Effect of Stress Triaxiality and Lode Angle on Ductile Fracture
Creator: Nia, Mahan
Date: 2023
Description: Although many ductile damage accumulation studies have been done in recent years, there is still insufficient research towards the development...
Show moreAlthough many ductile damage accumulation studies have been done in recent years, there is still insufficient research towards the development of ductile fracture models, mainly due to the difficulty of performing experiments under different states of multiaxial stress. The goals of this Ph.D. research are to (i) produce much-needed experimental data, (ii) investigate the performance of existing models against these data, and (iii) develop a new predictive ductile fracture model validated by experiments. The new model seeks to predict the fracture strain as a function of the stress triaxiality and normalized Lode angle. One of the prominent works in this area was done by Bai and Wierzbicki in 2008 by testing 2024-T351 aluminum alloy. They proposed an asymmetric 3D empirical fracture model with six model parameters. Thus, the Bai method was investigated alongside a new model for predicting ductile fracture. For that purpose, 2139-T8 aluminum alloy was chosen for our experimental program to evaluate these models better, and the data extracted from Bai's work was also used as an additional data set. An extensive experimental program was considered to create different stress states in the material, including tensile tests (with round smooth and four round notched and plate specimens), torsion, compression (with four smooth and two notched specimens), and shear-compression experiments (two different sizes). The specimens were longitudinally machined from a block of 2139-T8 aluminum alloy. The combined effects of two variables, stress triaxiality and normalized Lode angle, define a 3D fracture envelope for fracture strain. A parallel FE simulation (fine-tuned by the experimental results) has been performed for each experiment to evaluate the evolution of stress triaxiality and Lode angle in the gauge section of the specimens with complicated geometries. Finally, these results were used in developing two predictive fracture models. The first model is based on the Bai-Wierzbicki form of fracture. The second one is a new model that has been presented in this research. This new model is a modification of the Johnson-Cook fracture model and considers the simultaneous effects of Lode angle and stress triaxiality in fracture. The original Johnson-Cook fracture model (1984) does not consider the Lode angle effect. In the end, errors in the proposed approach to modeling ductile fracture have been compared to errors from Bai's work, resulting in the conclusions and recommendations for future studies.
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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: Utilizing Image Processing in Evaluation of Fibroblast Stimulation for Collagen Remodeling
Creator: Yoon, Shin Hae
Date: 2023
Description: This research delves into the realm of image processing as a pivotal component in the evaluation of fibroblast stimulation for collagen...
Show moreThis research delves into the realm of image processing as a pivotal component in the evaluation of fibroblast stimulation for collagen remodeling. The study focuses on unraveling the intricate synergy between electrospun silk fibroin-carbon nanotube (SF-CNT) fibers and electrical stimulation, working in harmony to enhance tissue regeneration. Building upon our previous work, we successfully engineered SF-CNT fibers through the electrospinning process, yielding highly aligned structures reminiscent of natural extracellular matrix proteins. These fibers were fortified with water stability through post-treatment with ethanol vapor, while subtle additions of carbon nanotubes (CNTs) significantly improved fiber alignment, strength, and conductivity without compromising biocompatibility. This innovative platform served as a cell culture matrix for fibroblasts harvested from pelvic organ prolapse (POP) patients, facilitating electrical stimulation that triggered a substantial increase in collagen production. In this study, we harnessed the power of various image-processing software tools, including ImageJ and Python, to analyze immunostained images of fibroblasts obtained from POP patients. Under carefully tailored electrical stimulation conditions, the stimulated cells exhibited an astonishing up to 11.97-fold increase in alpha-smooth muscle actin (α-SMA) expression, unequivocally signifying the successful activation of myofibroblasts. Additionally, in an animal model employing LOX-knockout mice to mimic collagen disorders associated with POP, the application of optimized electrical stimulation conditions for patient 003 led to a remarkable surge in collagen production and structural enhancement, underlining the potential of electrical stimulation in expediting tissue remodeling. Intriguingly, fibroblasts from patient 005 and patient 006 exhibited a distinct response, shedding light on the influence of POP severity on cellular behavior. This study firmly reinforces the imperative of personalized therapeutic approaches, emphasizing the need to customize treatment strategies to align with individual patient characteristics through innovative biological image analysis techniques.
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Title: Empowering Visually Impaired Individuals With Holistic Assistance Using Real-Time Spatial Awareness System
Creator: Yu, Xinrui
Date: 2024
Description: The integration of artificial intelligence (AI) into daily life opens unprecedented avenues for enhancing the experiences of visually impaired...
Show moreThe integration of artificial intelligence (AI) into daily life opens unprecedented avenues for enhancing the experiences of visually impaired individuals, offering them greater autonomy and quality of life. This thesis introduces a Visually Impaired Spatial Awareness (VISA) system designed to assist visually impaired individuals holistically through a structured approach. At the foundational level, the VISA system incorporates several key technologies to interpret the surroundings and assist in basic navigation tasks. It utilizes Augmented Reality (AR) markers to facilitate recognition of places and aid in navigation, employs neural network models for advanced object detection and tracking, and leverages depth information for accurate object localization. Progressing to the intermediate level, the VISA system integrates the data obtained from object detection and depth sensing to assist in more complex navigational tasks such as obstacle avoidance and pathfinding toward a desired destination. At the advanced level, the VISA system synthesizes the capabilities developed at the foundational and intermediate levels to enhance the spatial awareness of visually impaired users, allowing them to undertake complex tasks, such as navigating complex environments and locating specific items. The VISA system also emphasizes efficient human-machine interaction, incorporating text-to-speech and speech-to-text technologies to facilitate natural and intuitive communication between the user and the system. The VISA system's performance was evaluated in different environments simulating real-world scenarios. The experimental results show that the user can interact with our system intuitively with minimal effort, and affirm that the VISA system can effectively assist the visually impaired user in locating and reaching for objects, navigating indoors, identifying merchandise, and recognizing both handwritten and printed texts.
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Title: Two Essays on Mergers and Acquisitions
Creator: Xu, Yang
Date: 2024
Description: This dissertation is composed of two self-contained chapters that both relate to mergers and acquisitions (M&A). In the first essay, we...
Show moreThis dissertation is composed of two self-contained chapters that both relate to mergers and acquisitions (M&A). In the first essay, we examine the Delaware (DE) reincorporation effect on firms’ post-IPO behaviors on mergers and acquisitions. We find that firms’ DE reincorporation decisions enhance the likelihood of engaging in M&A as targets. However, as a tradeoff, DE reincorporated firms get lower takeover valuations compared to stay-at-home-state firms, and the acquisition of reincorporated firms is less likely to be successful. Our second essay aims to explore the role of the options market in price discovery for M&A. We find that the predictive power of the changes in implied volatility of the target firm stock for the takeover outcome is statistically and economically significant. The risk arbitrage portfolios incorporating filters derived from the options on stocks of the target firms generate annualized risk-adjusted abnormal returns between 2.6% and 5%, depending on the portfolio weighting method, the threshold of filters for the implied volatility change, and the asset pricing models applied for abnormal returns. The results are robust to different empirical setups and are not explained by traditional factors.
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Title: Effect of organic acid treatment in reducing Salmonella on six types of sprout seeds
Creator: Yang, Dachuan
Date: 2023
Description: Fresh sprouts present a special food safety concern as their growing conditions also favor the growth of pathogens such as Salmonella....
Show moreFresh sprouts present a special food safety concern as their growing conditions also favor the growth of pathogens such as Salmonella. Contamination in sprouts often originates from the seeds used for sprouting. The Produce Safety Rule requires that seeds used to grow sprouts be treated to reduce pathogens. The treatments may be applied by sprout growers or by seed suppliers. Although 20,000 ppm calcium hypochlorite is the most used seed treatment method, the high chlorine level can be hazardous to workers and the environment. Alternative seed treatment methods that are safe and environmentally friendly are needed. In addition, a post-treatment drying step is needed when seed suppliers are using chemical seed treatment methods. This study evaluated the efficacy of an organic acid solution for reducing Salmonella on six types of seeds (alfalfa, clover, radish, mung bean, onion, and broccoli). The impact of treatment on seed germination and sprout yield was also examined. Ten grams of seeds inoculated with a five-serotype cocktail of Salmonella were pre-rinsed with 40 ml of water twice and treated with 75.7 ml of the organic acid solution for 1 hour. The treated seeds were either not rinsed or rinsed with 40 ml of water twice before being dried in the biological safety cabinet for 24 hours. The Salmonella level, germination percentage, and sprout yield of seeds treated with water, seeds treated with the organic acid solution, seeds treated with organic acid, dried, and rinsed, and seeds treated with organic acids, dried, and not rinsed were compared. Salmonella reductions that could be achieved with this organic acid solution treatment were less than 0.5 log CFU/g without drying, 0.6-2.0 log CFU/g with drying and rinse, or 1.6-2.9 log CFU/g with drying and no rinse. Drying significantly enhanced the treatment efficacy (p < 0.05 ) on alfalfa, radish, mung bean, and onion seeds. If seeds were not rinsed after treatment, the log reductions achieved on mung bean and onion seeds were significantly higher (p < 0.05). If seeds were treated and rinsed, the germination rates of six types of seeds were not affected (p > 0.05) regardless of whether the seeds were dried or not. All treatments significantly decreased the sprout yield of clover seeds by 13% (p < 0.05 ). If seeds were not rinsed after treatment, the germination rates of clover and broccoli seeds were reduced by 7 and 9%, respectively, and the sprout yield of alfalfa seeds was reduced by 35%. Overall, the organic acid solution was ineffective when compared with 20,000 ppm calcium hypochlorite in reducing Salmonella on sprout seeds, although the drying step after treatment could improve the treatment efficacy.
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Title: Translational Research to Advance Remediation and Label-Free Detection
Creator: Rathnayake, Rathnayake A. Chathurika
Date: 2024
Description: Translational research acts as a vital link between fundamental scientific discoveries and their real-world applications, especially within...
Show moreTranslational research acts as a vital link between fundamental scientific discoveries and their real-world applications, especially within biotechnology and medical diagnostics. This interdisciplinary approach integrates knowledge from biology, chemistry, engineering, and medicine to create inventive solutions for urgent health challenges. Tissue remediation, essential in modern healthcare, seeks to restore the function and vitality of damaged tissues by imitating natural regenerative processes and employing biomaterials and scaffolds. Effective collaboration among academia, industry, and healthcare providers is essential for translating tissue remediation strategies into patient care, offering hope to those with injuries and chronic diseases.One project focuses on crafting biocompatible scaffolds resembling the body's extracellular matrix to facilitate tissue regeneration. This study focuses on enhancing collagen production, particularly for patients with pelvic organ prolapse (POP), using a combination of silk fibers functionalized with carbon nanotubes (SF-CNT) and electrical stimulation (ES). Key findings include superior alignment of SF-CNT fibers compared to pure silk fibers, with SF-CNT 0.1% showing optimal alignment. Higher CNT concentrations led to distorted fibers. SF-CNT 0.1% fibers displayed improved properties and minimal cytotoxicity, while ES increased collagen production, especially with SF-CNT 0.1% fibers. Customized ES conditions based on patient characteristics and tissue locations were crucial for optimal collagen enhancement. In vivo studies showed increased collagen content and improved fiber alignment with ES-treated fibroblast cells. Personalized ES conditions are essential for optimizing collagen enhancement, considering individual patient attributes and tissue-specific factors. The combination of SF-CNT fibers and ES offers promise for improving collagen production, particularly for POP patients. The study highlights the importance of personalized treatment strategies and tissue-specific considerations to maximize the effectiveness of electrical stimulation for collagen enhancement. Another promising avenue is the shift toward label-free detection methods in medical diagnostics, particularly for conditions like periodontitis. This project introduces an innovative method for rapid, label-free detection of bacterial species linked to periodontitis using Surface-Enhanced Raman Spectroscopy (SERS) combined with machine learning. Key advancements include optimizing saliva processing techniques, and establishing a reliable RT-qPCR method. SERS is utilized for bacterial detection with high accuracy, enhanced by incorporating a cell-free saliva matrix. These methods enable non-invasive, real-time characterization of biomolecular interactions and disease biomarkers, streamlining diagnostic processes and improving accessibility by eliminating the need for labeling agents. In the pursuit of translational research, collaboration and innovation are paramount. By translating scientific insights into practical solutions, researchers endeavor to advance tissue remediation and label-free detection, thereby contributing to a more sustainable, healthier, and safer future for all.
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Title: Monitoring Safety of Railway Tank Cars (Fall 1999) IPRO 013
Creator: Gupta, Kapil, Zukauskas, Elena, Patel, Jayesh, Lin, Shan
Date: 1999, 1999-12
Description: Railroad tank cars are efficient vehicles for the transport of large quantities of liquid commodities in North America. These commodities...
Show moreRailroad tank cars are efficient vehicles for the transport of large quantities of liquid commodities in North America. These commodities include foodstuffs as well as a wide range of chemicals use in the process industries. Transport Canada and the U.S. Department of Transportation collaborate in the formulation of rules and regulations for the transportation of hazardous commodities. While the incidence of non-accident release (NARs) is very small there is nevertheless a further collaborative effort by shippers and car owners alike to reduce the incidence of NARs to zero. One approach in reducing NARs is to develop a means to identify small leaks immediately, while the vehicle is in transit. The IPRO team will identify and evaluate methods for detecting small leaks using car mounted sensors and alerting the shipper of the leak automatically form remote locations. This includes consideration of how to mount sensors and telemetry devices, log data, predict unacceptable trends and incidents, and report them in a timely, reliable and cost-effective fashion. The technologies involved in the development of such a system would include characterization of target chemicals, sensors and date transmission, mounting to the tank car, evaluation of the econ0omic viability of the concepts, and identification of potential legal implications.
Sponsorship: Union Tank Car Company
Project Plan for IPRO 013: Monitoring Safety of Railway Tank Cars for the Fall 1999 semester
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Title: Web Portal that Creates about Engineering Careers for High School Students, Teachers and Counselors (Spring 2002) IPRO 309: Web_Portal_that_Creates_Awareness_about_Engineering_Careers_for_High_School_Students, Teachers_and_Counselors_IPRO309_Spring2002_Final_Presentation
Creator: Ilagan, Ryan, Lomeli, Victor, Oey, Mulyadi, Mardia, Aditya, Howard, Allan, Raic, Gordan, Sawhney, Vaibhav, Fan, Ping, Ostapczuk, Alex
Date: 2002, 2002-05
Description: There is a continuing need to provide information and motivational materials to high school students to interest them in engineering. These...
Show moreThere is a continuing need to provide information and motivational materials to high school students to interest them in engineering. These students would also benefit by learning about the various educational programs offered to help them meet their goals. Finally, information on the application process, especially the varying student aid packages from universities, government and industry would benefit high school students. There may be other services that would interest and benefit high school students that this project team could identify. There is also a wide variety of information already available to high school students and guidance counselors from individual universities as well as commercial and government organizations, associations and various publications that rank institutions. The sheer number of sources and volume of information about colleges and careers can be quite daunting to navigate. Everyone who has been through this process knows how frustrating and stressful it can be for students, parents and counselors in not having confidence that the best information was identified in a timely way to consider alternatives and make intelligent decisions. It is envisioned that this project would seek information from IIT engineering freshmen as well as high school students and counselors about current practices and trends in how the web and other resources are used in this process. Based on survey data, the project team will develop a web site or portal that can organize and provide information and services regarded as most valuable to high school students and counselors in their decision making process -- and do so in an integrated way, with appropriate planning and selection tools to support the process. It is envisioned that this could ultimately become part of a seamless service from the earliest consideration of career direction and college selection by high school students, through to specific career and employer selection by college students, and finally extending to support for alumni as they maintain their competitive edge in their professional practice. This project is a continuation of the Fall IPRO project. The team will continue to work closely with the admissions office to learn about university practices at IIT and elsewhere that relate to this web-based services concept
Project Plan for IPRO 309: Web Portal that Creates about Engineering Careers for High School Students, Teachers and Counselors for the Spring 2002 semester
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Title: Monitoring Safety of Railway Tank Cars (Fall 1999) IPRO 013: Monitoring Safety of Railway Tank Cars IPRO013 Fall1999 Final Presentation
Creator: Gupta, Kapil, Zukauskas, Elena, Patel, Jayesh, Lin, Shan
Date: 1999, 1999-12
Description: Railroad tank cars are efficient vehicles for the transport of large quantities of liquid commodities in North America. These commodities...
Show moreRailroad tank cars are efficient vehicles for the transport of large quantities of liquid commodities in North America. These commodities include foodstuffs as well as a wide range of chemicals use in the process industries. Transport Canada and the U.S. Department of Transportation collaborate in the formulation of rules and regulations for the transportation of hazardous commodities. While the incidence of non-accident release (NARs) is very small there is nevertheless a further collaborative effort by shippers and car owners alike to reduce the incidence of NARs to zero. One approach in reducing NARs is to develop a means to identify small leaks immediately, while the vehicle is in transit. The IPRO team will identify and evaluate methods for detecting small leaks using car mounted sensors and alerting the shipper of the leak automatically form remote locations. This includes consideration of how to mount sensors and telemetry devices, log data, predict unacceptable trends and incidents, and report them in a timely, reliable and cost-effective fashion. The technologies involved in the development of such a system would include characterization of target chemicals, sensors and date transmission, mounting to the tank car, evaluation of the econ0omic viability of the concepts, and identification of potential legal implications.
Sponsorship: Union Tank Car Company
Project Plan for IPRO 013: Monitoring Safety of Railway Tank Cars for the Fall 1999 semester
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Title: Monitoring Safety of Railway Tank Cars (Fall 1999) IPRO 013: Monitoring Safety of Railway Tank Cars IPRO013 Fall1999 Final Report
Creator: Gupta, Kapil, Zukauskas, Elena, Patel, Jayesh, Lin, Shan
Date: 1999, 1999-12
Description: Railroad tank cars are efficient vehicles for the transport of large quantities of liquid commodities in North America. These commodities...
Show moreRailroad tank cars are efficient vehicles for the transport of large quantities of liquid commodities in North America. These commodities include foodstuffs as well as a wide range of chemicals use in the process industries. Transport Canada and the U.S. Department of Transportation collaborate in the formulation of rules and regulations for the transportation of hazardous commodities. While the incidence of non-accident release (NARs) is very small there is nevertheless a further collaborative effort by shippers and car owners alike to reduce the incidence of NARs to zero. One approach in reducing NARs is to develop a means to identify small leaks immediately, while the vehicle is in transit. The IPRO team will identify and evaluate methods for detecting small leaks using car mounted sensors and alerting the shipper of the leak automatically form remote locations. This includes consideration of how to mount sensors and telemetry devices, log data, predict unacceptable trends and incidents, and report them in a timely, reliable and cost-effective fashion. The technologies involved in the development of such a system would include characterization of target chemicals, sensors and date transmission, mounting to the tank car, evaluation of the econ0omic viability of the concepts, and identification of potential legal implications.
Sponsorship: Union Tank Car Company
Project Plan for IPRO 013: Monitoring Safety of Railway Tank Cars for the Fall 1999 semester
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Title: re|build
Creator: Clithero, Katherine
Date: 2012-05-02, 2012-05
Description: On May 22, 2011, Joplin, Missouri was struck by a powerful EF-5 tornado. The nearly one-mile wide tornado cut a path almost 22 miles in length...
Show moreOn May 22, 2011, Joplin, Missouri was struck by a powerful EF-5 tornado. The nearly one-mile wide tornado cut a path almost 22 miles in length, destroying over 7,000 homes and about 2,000 other structures. Among the buildings completely destroyed during the storm was Joplin High School. The rebuilding of the school is an important step for the community to heal and grow from the devastation. The intent of the design is to improve the quality of education by incorporating collaborative learning spaces, integrating technology and promoting environmental responsibility.
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Title: Monitoring Safety of Railway Tank Cars (Fall 1999) IPRO 013
Creator: Gupta, Kapil, Zukauskas, Elena, Patel, Jayesh, Lin, Shan
Date: 1999, 1999-12
Description: Railroad tank cars are efficient vehicles for the transport of large quantities of liquid commodities in North America. These commodities...
Show moreRailroad tank cars are efficient vehicles for the transport of large quantities of liquid commodities in North America. These commodities include foodstuffs as well as a wide range of chemicals use in the process industries. Transport Canada and the U.S. Department of Transportation collaborate in the formulation of rules and regulations for the transportation of hazardous commodities. While the incidence of non-accident release (NARs) is very small there is nevertheless a further collaborative effort by shippers and car owners alike to reduce the incidence of NARs to zero. One approach in reducing NARs is to develop a means to identify small leaks immediately, while the vehicle is in transit. The IPRO team will identify and evaluate methods for detecting small leaks using car mounted sensors and alerting the shipper of the leak automatically form remote locations. This includes consideration of how to mount sensors and telemetry devices, log data, predict unacceptable trends and incidents, and report them in a timely, reliable and cost-effective fashion. The technologies involved in the development of such a system would include characterization of target chemicals, sensors and date transmission, mounting to the tank car, evaluation of the econ0omic viability of the concepts, and identification of potential legal implications.
Sponsorship: Union Tank Car Company
Project Plan for IPRO 013: Monitoring Safety of Railway Tank Cars for the Fall 1999 semester
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