bluuebunny/crossref_metadata_2025 huggingface dataset:
Leadership in School District Consolidation and the Impact on Student Outcomes
Authors:   , Balcom Janet Jones , Bureau W. Edward
Published: July 2021

In November 2007, area voters approved the consolidating of four districts into the Twin Rivers Unified School District (TRUSD) intending to create an articulated pre-K-adult urban district of 27,000 students. Since the creation of TRUSD no studies have been conducted to measure the impact of the consolidation on student achievement and related student outcomes. The important and compelling question regarding the consolidation is: Did the students of the newly formed Twin Rivers Unified School District (TRUSD) benefit from the consolidation? This research explored key areas of student outcomes and compared the available achievement, discipline, and truancy data before and after the consolidation. Student outcome data before the consolidation indicated some significant concerns, particularly in achievement. This mixed-method case study examined the impact of school district consolidation on student achievement and related student outcomes since the formation of the TRUSD. The study provided the opportunity for triangulation of multiple data sources and evidence sources, as it utilized staff interviews to drive the direction of study as well as solutions to the problem. Additionally, the research reviewed district pre and post consolidation data in the areas of student outcomes including achievement, truancy, and discipline.
A leaky waveguide all-optical analog-to-digital converter
Authors:   , Hou Xiaobo , Rosen Warren A. , Daryoush Afshin S.
Published: July 2021

In this thesis we describe a novel all-optical analog-to-digital converter (AOADC) based on a leaky waveguide deflector. The principle of the spatial sampling AOADC is to convert an electrical signal to its corresponding optical deflection angle and then sample and quantize this angle in the spatial domain, instead of the amplitude domain. This AOADC is designed for broadband digital receivers working at frequencies above 20 GHz (a minimum 40 GS/s sampling rate) and provides a resolution higher than 6 bits. An original design based on GRISM (Grating and pRISM) is investigated for a high-resolution ADC implementation; and its challenges have been identified. The investigation provides a general model of spatial sampling AOADCs and highlights their advantages of immunity to optical intensity fluctuation. Later we proposed an AOADC that employs a leaky waveguide structure that is different from any other optical ADC. The AOADC consists of a sampler based on a mode-locked laser and a leaky waveguide deflector driven by traveling wave electrodes, a quantizer based on an integrated optical collector array and broadband photodetectors. These components provide the AOADC with a higher deflection angle and angular resolution resulting in high bit resolution without consuming significant power. The quantization of the deflection angle is done by a simple spatial quantizer that digitizes as well as encodes the signal simultaneously. A detailed design of the E-O deflector and the spatial quantizer has been analyzed and simulated; and some preliminary tests have been conducted. This thesis summarizes our contributions in designing and modeling this novel spatial sampling AOADC.
Biomedical Information Extraction
Authors:   , Huang Zhong , Hu Xiaohua
Published: July 2021

Disease associated gene discovery is a critical step to realize the future of personalized medicine. However empirical and clinical validation of disease associated genes are time consuming and expensive. In silico discovery of disease associated genes from literature is therefore becoming the first essential step for biomarker discovery to support hypothesis formulation and decision making. Completion of human genome project and advent of high-throughput technology have produced tremendous amount of data, which results in exponential growing of biomedical knowledge deposited in literature database. The sheer quantity of unexplored information causes information overflow for biomedical researchers, and poses big challenge for informatics researchers to address user's information extraction needs. This thesis focused on mining disease associated genes from PubMed literature database using machine learning and graph theory based information extraction (IE) methods. Mining disease associated genes is not trivial and requires pipelines of information extraction steps and methods. Beginning from named entity recognition (NER), the author introduced semantic concept type into feature space for conditional random fields machine learning and demonstrated the effectiveness of the concept feature for disease NER. The effects of domain specific POS tagging, domain specific dictionaries, and named entity encoding scheme on NER performance were also explored. Experimental results show that by combining knowledge base with concept feature space, it can significantly improve the overall disease NER performance. It has also shown that shallow linguistic features of global and local word sequence context can be used with string kernel based supporting vector machine (SVM) for efficient disease-gene relation extraction. Lastly, the disease-associated gene network was constructed by utilizing concept co-occurrence matrix computed from disease focused document collection, and subjected to systematic topology analysis. The gene network was then merged with a seed-gene expanded network to form heterogeneous disease-gene network. The author identified and prioritized disease-associated genes by graph centrality measurements. This novel approach provides a new mean for disease associated gene extraction from large corpora.
Evolution of Star Clusters in Time-Variable Tidal Fields
Authors:   , Mamikonyan Ernest N. , McMillan Stephen L. W.
Published: July 2021

Strong tidal forces can dominate star cluster evolution in merging galaxies, determining their mass loss rates and lifetimes. In order to model this evolution, we have developed a second-order accurate numerical method for integrating a star cluster in an arbitrary, time-variable tidal field. We obtain realistic tidal histories from a galaxy merger simulation including sink particles, which we interpret as young star clusters. Coupling those tidal accelerations to N-body models of isolated clusters, we perform detailed dynamical studies. We extend the Kira N-body integrator to handle these external fields. This generalizes the formalism previously used to explore the dynamical effects of the galactic tidal field on clusters in circular orbits. Furthermore, we develop an effective semi-analytic model that can be used for fast estimation of cluster mass loss in a galactic tidal field. We use this model to study the evolution of globular cluster mass function in isolated and merging galaxies.
Movements, Behaviors and Threats to Loggerhead Turtles (Caretta caretta) in the Mediterranean Sea
Authors:   , Patel Samir Harshad , Spotila James Robert , Morreale Stephen J.
Published: July 2021

The purpose of this study was to determine the at-sea behavior of loggerhead turtles (Caretta caretta) in the Mediterranean Sea in order to gain a better understanding of the various environmental factors that play a role in their survival. By determining the environmental conditions that have a controlling force over foraging and nesting success, more accurate projections can be made on the future of this declining subpopulation of loggerheads. I deployed 20 satellite transmitters on postnesting adult loggerhead turtles from Rethymno, Crete, Greece, with 19 functioning through migration. Using a changepoint analysis model, I determined that loggerheads in the Mediterranean exhibited 5 behavior modes. Within these modes were migration, foraging and overwintering, along with newly discovered transition modes between each established sea turtle behavior. Overall, the turtles exhibited 3 unique postnesting strategies, 9 migrated to the North African coast, 6 migrated into the Aegean Sea and 4 remained within the waters of Crete. These three strategies corresponded to fitness differences between the turtles. The northern turtles were larger and had larger clutch sizes than those foraging near Crete and Africa. This corresponded to the abundance of prey from each region. The benthic environment of the Aegean had the largest prey abundance compared to the other sites. Around Crete there is very limited benthic environment to support loggerhead foraging, and in the Gulf of Gabes the prey abundances are reduced due to a high influx of industrial runoff. The Gulf of Gabes is home to ~40% of loggerheads nesting in Greece, and as global warming continues, the rising temperature is expected to exacerbate the deterioration of the benthic environment. Furthermore, there is already a strong female bias in sex ratio for Mediterranean loggerheads, which is expected to continue to get stronger as beach temperatures rise and precipitation declines. Loggerheads may be able to compensate for these changes, and I found that their nesting phenology is expected to shift earlier by as much as 52 - 74 days by 2100; however the factors threatening the survival of this species may be too strong to overcome.
Model of water evaporation stage during drying of latex coatings
Authors:   , Gundabala Venkata Ramana , Cairncross Richard Allan
Published: July 2021

AbstractModel of Water Evaporation Stage during Drying of Latex CoatingsVenkata Ramana GundabalaRichard Allan Cairncross, Ph. DTraditional solvent-based coatings pose several environmental concerns due to high volatility and polluting effects of the solvents. Water-based latex coatings have been identified as a worthy alternative because of the ease of application; however the properties of latex coatings are often inferior to solvent-based coatings due to incomplete film formation. To achieve suitable film properties for most applications, it is necessary for latex particles to aggregate and coalescence into a continuous film during drying. Film formation during drying of latex coatings is occurs in three stages. This thesis presents a particle dynamics model that predicts evolution of particle layers and packing structure during the first stage of drying of latex coatings, which is period of constant evaporation rate. In this model the inertia of particles is negligible and the velocity and trajectory of each particle is determined by balancing the drag force on the particle with interparticle repulsion, surface tension and Brownian forces. DLVO theory was used to predict the screened electrostatic interactions between particles. The Brownian force has random magnitude and direction to simulate random particle motions observed in colloidal systems. Areal density profiles and 3D plots are used to make base case and parametric analysis on evolution of particle layers and packing structure. The parameters used for investigation include electrolyte concentration, drying rate, particle size, magnitude of random force variance, initial volume fraction, and initial particle distribution. FCC and HCP are the most commonly observed packing structures. The results show that use of smaller particle sizes, lower electrolyte concentrations, and slower drying rates produce more highly ordered packing structure.
Technical and Vocational Education and Training (TVET)
Authors:   , Dike Victor Ebipuruonwu , Bureau W. Edward
Published: July 2021

The descriptive mixed-methods study explores and describes the challenges and prospects of the growth and development of technical and vocational education and training (TVET) schools and science-based technology education in Nigeria. It is not understood how Nigerians in the United States perceive the impacts of governmental policies on education and the eventual contribution of graduates of TVET schools in Nigeria to the country's economic growth and development. The purpose of this descriptive mixed-methods study was to discover the opinions and perceptions of Nigerians in the United States regarding the consequences stemming from the Nigerian government's limited level of support for technical and vocational education and training (TVET) schools and programs. The questions for the descriptive mixed-methods study enable us to understand how the Nigerian government's limited level of support for TVET relate to the shortage of highly skilled manpower and technological capabilities and the policy interventions that will improve the situation and enhance national development. To provide a practical solution to the problem, my stances and conceptual framework hinged on human-capital development, leadership and governance, and technological capabilities. A triangulation of both quantitative and qualitative methods was utilized for data collection. To collect primary quantitative data for the study, 100 questionnaires were distributed; eight semi-structured interviews and focus-group sessions of six individuals were utilized to capture qualitative data. Quantitative data were scored on a 5-point Likert-type scale and qualitative data from the semi-structured questions were systematically examined, analyzed, coded, and integrated into the main data. Simple descriptive statistics of frequency counts and percentages were employed to analyze and describe the data. The results were expected to enable the researcher to better understand the topic, reach a valid conclusion, and recommend possible practical solutions to the problem.
Atomic ordering effects on (LaCrO₃)_n/(LaFeO₃)_n perovskite superlattices for solar absorption
Authors:   , Cordi Adam M. , Rondinelli James M.
Published: July 2021

Due to the ever-increasing energy demand and heavy dependence on non-renewable resources, the search for an economically competitive renewable energy resource is at an all-time high. Among the identified renewable energy resources, sunlight is the most available, however, the conversion to electricity is largely determined by the absorbent layer of a solar cell, often reaching only ~15% efficiency in commercial applications. Consequently, it is necessary to develop novel materials to enhance said absorbing layer. Oxide heterostructures present themselves as an alternative as they allow for chemical doping, which can lead to higher efficiency due to optical band gaps in the optimally efficient range, band-gap graded materials, and an internal potential gradient for charge carrier separation. Perovskite oxide superlattices of LaCrO₃ and LaFeO₃ have shown varying magnetic, electronic, and optical properties through atomic ordering. This presents the interesting possibility to tune properties based purely on the local chemical environment. Recently, a (LaCrO₃)₁/(LaFeO₃)₁ rock-salt ordered superlattice has shown an anomalous optical band gap of 1.6 eV, ~1 eV below that of either parent compound, making it suitable for solar applications. Density functional theory is used to investigate the effect of artificial atomic ordering and superlattice periodicity in layered and rock-salt configurations on the optical band gap. Two conclusions are drawn from this study. First, rock-salt ordering is predicted to reduce the optical band gap following Hunds rules and the Goodenough Kanamori rules for superexchange interactions with a ferrimagnetic spin ordering, resulting in a net magnetization of ~2 [mu]_[beta], which is not observed in either bulk compound. Second, the variation in superlattice periodicity, specifically a (LaCrO₃)₂/(LaFeO₃)₂ structure, lifts inversion symmetry and leads to a spontaneous electric polarization of 0.0280 [mu]C/cm², possibly increasing optical absorption efficiency through increased charge carrier separation.
Synthesis and Characterization of Ti₃SiC₂/Mg and Cr₂AlC/Mg Composites
Authors:   , Nelson Matthew Jared , Barsoum Michel W.
Published: July 2021

High strength, light-weight materials are in high demand in many applications; especially aerospace and the military. The focus of this work is to report on the fabrication and characterization of Ti₃SiC₂ and Cr₂AlC MAX phase reinforced Mg and Mg-alloy metal matrix composites synthesized by pressureless melt infiltration. Pure Mg and Al-containing Mg-alloys (AZ31, AZ61 & AZ91) with varying Al content were matrices with loadings of ~ 45 1 vol. %. The resulting microstructures and mechanical properties were characterized by X-ray diffraction, scanning electron microscopy (SEM), and compressive stress testing. SEM revealed kinked, delaminated, and elongated Ti₃SiC₂ grain, and non-deformed, rounded Cr₂AlC grain morphologies. Like in the Ti₂AlC/Mg composite system, increasing the Al wt. % content in the matrix enhanced the mechanical properties of the Ti₃SiC₂ composite system, but had a deleterious effect on the properties of the Cr₂AlC composite system. At 1.9 0.1 GPa, 346 4 MPa and 617 10 MPa, the Vickers hardness, yield strength and ultimate compressive strength, respectively, of the Ti₃SiC₂/AZ91 composite were the highest in this study. All composites fabricated in this work exhibited fully and spontaneously reversible hysteresis loops due to the back and forth motion of dislocations. A small change in reinforcement volume fraction was found to affect the measured mechanical properties.
Formation of Thin Films from MXene Flakes
Authors:   , Steinberg Jacob A. , Gogotsi Yury
Published: July 2021

MXenes, a family of two-dimensional ceramic materials comprised of an early transition metal and carbon or nitrogen, have only been successfully synthesized since 2011. Relatively little experimental work on MXenes exists, but the study of MXenes so far has offered strong indications that their unique combination of behaviors common to both metals and ceramics makes MXenes well suited for several applications. In particular, MXenes' ability to conduct heat and electricity very well while being thin enough to be transparent to visible light makes them a particularly promising material for conductive coatings in a variety of products. This work focuses on pursuit of a variety of methods for successfully depositing thin films of the MXene Ti₃C₂ and demonstrates the use of self-assembled monolayers of both an aminosilane and poly-l-lysine to deposit thin films of MXene on glass and silicon substrates. The existence of films was confirmed using scanning electron microscopy, and the ultraviolet-visible absorption of light by the films was characterized using ultraviolet-visible spectrophotometry. The work herein facilitates the further deposition of thin films of MXene and the optimization of their properties.
Organic and Organic-Inorganic Hybrids for Optoelectronic, Photovoltaic, and Carbon Sequestration Applications
Authors:   , Swearer Dayne Francis , Ji Haifeng
Published: July 2021

The sum of this thesis focuses on the development of organic and organicinorganic hybrid systems for optoelectronic, photovoltaic, and carbon sequestration applications. Within, two compounds have been successfully synthesized as potential precursors to highly conjugated N-heterocyclic aromatic ligands for transition metal based photosensitizers in dye-sensitized solar cells. The synthetic procedures and potential for future investigation are discussed. Similarly, the self-assembly of both organic and metal-organic supramolecular assemblies were investigated with a focus on using aromatic diimides for this purpose. 1,4,5,8-naphthalenediimde was found to undergo self-assembly into long, single crystal wires with solution phase processing in DMSO. These wires were characterized for composition and optical properties and integrated into a working device for sensing light sources. Likewise, perylene-3,4,9,10- tetracarboxylic acid was isolated using a variety of metals in the (II) and (III) oxidation states. These materials were crystals as films on a gold surface and investigated as potential materials for carbon dioxide sequestration and photocatalytic reduction of carbon dioxide.
Developing digital Chinese water-ink animation Renaissance of Chinese Water-ink Animation
Authors:   , Zhou Yue , Wagner Michael G.
Published: July 2021

In this paper we present an introduction to Chinese water-ink animations and an exploration of the style and technique that defines an animation as Chinese water-ink. Building upon these traditional techniques we introduce new digital styles to reconstruct important elements of water-ink animation within a virtual environment. Specifically we explore the addition of rice paper as an element within the digital and suggest new ways in which digital Chinese water-ink animation might grow in the future.
Gambia Radio and Television Services
Authors:   , Dibba Amie Lamin , Salas Philip W. , Tedesco Albert S.
Published: July 2021

The Gambia, West Africa has only one operational television station. The Gambia Radio and Television Services (GRTS) serves as the sole television station in the country and is government owned. Although GRTS is a public government owned station, it does sell airtime for commercial use. The purpose of this thesis is to analyze the television program selection and scheduling strategies at GRTS in comparison to the needs of its viewing audience and potential advertisers. The goal of this research is not only to provide a current analysis of the programming department of GRTS in terms of scheduling and strategies, it is also to highlight the effects of those decisions on the audience as well as the current and potential advertisers utilizing the platform. To give a broader understanding of the inner workings of GRTS, a more in depth analysis will be utilized regarding other relevant departments within the institution. For this study, the methodologies used were interviews, surveys and field observations.
The New Newsroom
Authors:   , Hanley Kelsey M. , Tedesco Albert S.
Published: July 2021

This thesis addresses the integration and impact of digital and social media into local television news stations across the country through 2013. Digital and social media have allowed local television stations to stay engaged with their viewers on a 24/7 basis, by promoting constant conversation. Studies note that social media is on a continuous spiral of growth through which viewers have the opportunity to contribute to the news gathering process, and in turn it allows newscasters to continue an ongoing conversation with their viewers in real time. By looking into all aspects of local television newsrooms, this thesis investigates how digital and social media are changing the journalistic landscape. From the newsgathering and news dissemination process, to staffing and revenue streams, digital and social media affect every department in a local television news station. Special attention is given to the three-screen approach and mobile technology, as well as the social platforms themselves, to determine how local television stations have used these particular technologies in their everyday business practice. This thesis also includes a ten question, open ended survey of the Philadelphia Designated Market Area (DMA) to determine how digital and social media have affected the four major commercial television stations in the area (ABC, CBS, Fox, and NBC). The survey was distributed to television managers, creative service teams, web teams, and the on-air talent with twelve survey's being returned from at least one representative per station. After analyzing information from the literature and survey data, a conclusive hypothesis was formulated about the future of digital and social media use at local television news stations in the coming years.
The Effect of Mobile Devices and Computers on Syndicated Television Content
Authors:   , Scully Daniel Patrick , Tedesco Albert S.
Published: July 2021

From the 1950's to the 21st century, television viewing has continued to evolve, utilizing the technology available. The 21st century saw an increase in the flexibility of where and how viewers could watch programming. This was due to the availability of programs on computers and mobile devices (collectively, alternate devices). An analysis of the current parameters of popular programing and an examination of how viewers' tastes differ between these two viewing methods will enable production companies to have the information they need to aid in their production decisions. In order to accomplish this goal, this thesis employed two methods. First, this thesis analyzed the most popular television shows on traditional television and alternative devices by genre. Secondly, a Qualtrics survey was conducted which asked detailed questions about the respondents' viewing habits on traditional television, computers and on mobile devices. The survey delved into the reasons behind the respondents' choices and which elements were most important to them. Overall, the resulting data pointed to a diversification in the type of programming people will watch on alternate devices versus the programming the same customers would watch on traditional television. In terms of how much each specific element of a program affects viewers' decisions to watch, the quality of the program's writing was found to be the most important factor, across all viewing platforms. Therefore, the two main recommendations would be: first, production companies should work to fill the genre niches that were found to be popular online but are currently being underserved; second, production companies should focus on the quality of the writing of their programming, regardless of the genre.
The evolution of MTV
Authors:   , Zhao Minting , Tedesco Albert S.
Published: July 2021

MTV revolutionized the world of music and television in the 80s and 90s, but the network had to shift its focus to reality programming in order to thrive in a highly competitive business. MTV successfully rebranded itself and gained ground among younger demographics with a variety of reality programs. The competition from both broadcast and cable channels has become heightened and 2013 was an extremely challenging year for MTV. The network had to conclude its most-watched series ever, Jersey Shore, after the show's fourth and fifth seasons started showing signs of fatigue. The purpose of the thesis is to provide a brief discussion of the cable TV industry's current competitive landscape, a thorough analysis of MTV's current programming strategy, and recommendations for the network's programming strategy going forward. In order to gain the in-depth knowledge required for the thesis, a qualitative research methodology was utilized with comparisons of MTV and several other competitors' schedules and ratings, and a thorough analysis of MTV's current programming strategy. Although MTV has not launched enough hits after the conclusion of Jersey Shore, 2013 Nielsen ratings reports indicate that MTV is still one of the dominating cable networks among younger demographics, especially within the female 15-24 group. In order to offset the loss of Jersey Shore and continue to dominate the millennial generation, the network needs to not only strengthen its primetime programming but also increase primetime hours, which will help improve ratings across the schedule. MTV also needs to invest more in movie acquisitions, which will help bolster ratings for its weekend and holiday schedules.
MXenes
Authors:   , Abdelmalak Michael Naguib , Gogotsi Yury
Published: July 2021

Two-dimensional, 2D, materials, such as graphene, possess a unique morphology compared to their 3D counterparts, from which interesting and novel properties arise. Currently, the number of non-oxide materials that have been exfoliated is limited to two fairly small groups, viz. hexagonal, van der Waals bonded structures (e.g. graphene and BN) and layered transition metal chalcogenides. The MAX phases are a well established family of layered ternary transition metal carbides and/or nitrides, with a composition of M_[n+1]AX_n, where M is an early transition metal, A is one of A group elements, X is C and/or N; with n = 1, 2, or 3. The aim of this work is to exfoliate the MAX phases and produce 2D layers of transition metals carbides and/or nitrides by the selective etching of the A layers from the MAX phases. We labeled the resulting 2D Mn+1Xn layers "MXenes" to emphasize the loss of the A group element from the MAX phases and the suffix "ene" to emphasize their 2D nature and their similarity to graphene. The etching process was carried out using aqueous hydrofluoric acid at room temperature. Thirteen different MXenes were produced as a result of this work, viz., Ti2C, Nb2C, V2C, Mo2C, (Ti0.5,Nb0.5)2C, (Ti0.5,V0.5)2C, Ti₃C₂, (Ti0.5,V0.5)3C2, (V0.5,Cr0.5)3C2, Ti3CN, Ta4C3, Nb4C3 and (Nb0.5,V0.5)4C3. The as-synthesized MXenes were terminated with a mixture of OH, O, and/or F groups. Sonicating MXenes resulted in separating the stacked layers to a small extent. When Ti₃C₂ was intercalated with dimethylsulfoxide, however, followed by sonication in water, large-scale delamination occurred, which resulted in aqueous colloidal solutions that could in turn be fabricated into MXene "paper". MXenes were found to be electrically conductive, hydrophilic and stable in aqueous environments, a rare combination indeed, with huge potential in many applications, from energy storage, to sensors to catalysts. This work focused on the use of MXenes as electrode materials in Li-ion batteries. They exhibited excellent capability to handle high cycling rates with good gravimetric capacities. The lithiation and delithiation were found to be due to redox intercalation/deintercalation reactions.
Essays on Complementary Products and Strategies
Authors:   , Baburaj Yamuna , Narayanan Vadake K.
Published: July 2021

Complementary products contribute significantly to the growth and sustenance of primary products and platforms in many high technology product markets. Although different literatures have investigated issues related to complementary products, our understanding on this topic is limited. This dissertation aims to address some of the questions in the growing literature on complementary products. Following the literature review, the third chapter develops the conceptual underpinnings of product complementarity and examines commonly specified definitions to clarify the dimensions of product complementarity. The fourth chapter addresses the boundary question from the perspective of a primary product firm. The theoretical model identifies the antecedents of the internalization decision emphasizing the influence of type of product complementarity and key environmental contingences, viz., technological and market demand uncertainty. The fourth and fifth chapters of the thesis examine the role of type of complementarity in predicting the governance choices of 31 public businesses over a time frame of 26 years in the PC industry, a setting where complementary products have significantly influenced the competitive and technological landscape. The study findings reveal that type of complementarity along with environmental contingences influence a firm's choice of internalization, alliances or complementor make. Market demand uncertainty influences the choice of strategy towards complementary product for moderately increasing levels of uncertainty while technological uncertainty predicts the governance choices for both low and moderately increasing levels of uncertainty. In addition, in accordance with emerging literature in the Transaction Cost Economics logic (Leiblein & Miller, 2002; Jacobides, 2005) the findings highlight the role of firm capabilities. The dissertation attempts to contribute to the strategy literature by explicating the importance of nature of complementary products, so far not addressed in traditional TCE work.
Chromatographic Analysis and Separation of Short RNA Oligonucleotides with Novel Liquid Chromatography Methods
Authors:   , Biba Mirlinda , Foley Joe Preston , Welch Christopher J.
Published: July 2021

Synthetic oligonucleotides have become increasingly important as part of new developments in the use of antisense and small interfering ribonucleic acid (siRNA) as potential therapies for the treatment of various different diseases. The development of analytical methods for the sensitive and quantitative analysis and separation of oligonucleotides is an essential part for the advancement of this research area. A typical oligonucleotide therapeutic sample is a short RNA-based oligonucleotide with about 21-mer length (~7-8 kDa), and with possible chemical modifications prepared by chemical synthesis using an automated synthesizer. Due to their relatively large sizes compared to typical small-molecule compounds, oligonucleotides can be difficult to analyze with traditional analytical methods. There are many different analytical techniques reported for the analysis and separation of oligonucleotides, including capillary gel electrophoresis (CGE), anion-exchange high performance liquid chromatography (AEX-HPLC), and ion-pair reversed-phase liquid chromatography (IP-RPLC). In these research studies, existing liquid chromatography methods for the separation of oligonucleotides were evaluated for improved separations. New and novel approaches were also explored for more efficient analysis and separation of oligonucleotides.
Combining fabrication and surface modification techniques to develop cell-laden microfluidic devices
Authors:   , Hamid Qudus , Sun Wei
Published: July 2021

Micro-Electro-Mechanical Systems (MEMS) technologies illustrate the potential for many applications in the field of tissue engineering, regenerative medicine, and life sciences. The fabrication of tissue models integrates the multidisciplinary field of life sciences and engineering. Presently, monolayer cell cultures are frequently used to investigate potential anti-cancer agents. These monolayer cultures give limited feedback on the effects of the micro-environment. A micro-environment, which mimics that of the target tissue, will eliminate the limitations of the traditional mainstays of tissue research. The fabrication of such micro-environment requires a thorough investigation of the actual target organ and/or tissue. Microfabrication techniques are utilized to develop microfluidic channels for continuous nutrition supply to cells inside a micro-environment. The ability of cells to build tissues and maintain tissue-specific functions depends on the interaction between cells and the extracellular matrix (ECM). Three-dimensional tissue platforms are rapidly becoming the method of choice for quantification of the heterogeneity of cell populations for many diagnostic and drug therapy applications. Microfluidic sensors and the integration of sensors with microfluidic systems are often described as miniature versions of their macro-scale counterparts. This technology presents unique advantages for handling costly and difficult-to-obtain samples and reagents as a typical system requires between 100 nL to 10[mu]L of working fluid. The fabrication of a fully functional cell-based biosensor utilizes both biological patterning and microfabrication techniques. SU-8 is a popular photosensitive epoxy-based polymer in MEMS. The patterning of bare SU-8 alone does not provide the appropriate ECM necessary to develop microsystems for biological applications. Manipulating the chemical composition of SU-8 will enhance the biological compatibility, giving the fabricated constructs the appropriate ECM needed to promote a functional tissue array. The objective of this research is to investigate the integration of maskless fabrication, direct cell deposition, and surface modification techniques to engineer cell-laden microfluidics. This thesis presents advances in additive manufacturing techniques, the utilization of plasma chemistry to enhance surface functionalization, and manipulation of photo-polymerization to investigate new approaches to assemble cell-laden microfluidics.
Recommendation with contextual information
Authors:   , Huang Jia , Hu Xiaohua
Published: July 2021

Information retrieval (IR) systems have tremendously broaden users' access to information. However, users need to select their needs from trillions of information indexed daily. Due to the "semantic gap" between queries and indexed terms in IR system, whether users can satisfy their needs depends on whether they use the correct terms as queries. Recommender systems, have become a counterpart of information retrieval systems such as Google. They do not require users to specify their information needs in advance. They model users' preferences based on their history data, and automatically recommend items which satisfy their needs. In this way, both semantic gap and information overload can be alleviated. Collaborative filtering is the most popular recommendation algorithm used in academia and industry. However, it suffers from the cold start problem, where it cannot recommend new items to users or give recommendation to new users. Its recommendations also bias towards popular items. The goal of this thesis is to develop recommendation algorithms which can solve the item-side and user-side cold-start problems. We incorporate item content to solve the item-side cold start problem, and incorporate user similarity networks or social networks to solve the user-side cold-start problem. Our contributions are listed as follows. First, we develop a content-based movie recommendation algorithm which incorporates user, actor, and movie into the same model. Second, we develop a content-based music recommendation algorithm. The core component is a hierarchical dynamic programming algorithm to compute music similarities. The resulting music similarity matrix is then employed to make recommendations. Third, we apply social recommendation algorithms on Douban dataset. We look into a "Twitter-like" user-follower social network to see if it can improve recommendation performance. Finally, we validate the existence of social influence. We also analyze the social influence by investigating the correlation between one's influence and centrality, and by investigating how recommendation effectiveness changes with the number of recommendations.
The Effects of the Timing of Post-Purchase Price Reductions and Brand Strength on Consumers' Price Unfairness Perceptions
Authors:   , Koc Umit , Suri Rajneesh
Published: July 2021

Pricing literature examined the impact of price increases or decreases on price unfairness perceptions in pre-purchase contexts but post-purchase price reduction context received limited attention. Moreover, the impact of brand strength on perceptions of price unfairness in a post-purchase price reduction context has received little attention despite evidence that shows that brand names impact consumers' internal reference price and quality perceptions. Hence, this dissertation aims to close this gap by inquiring about the impact of brand strength and depth of post-purchase price reductions on price unfairness perceptions over time by relying on construal level theory and acquisition-transaction value model. In two experiments, four new scales that are suitable for post-purchase price reduction context were developed and refined: Perceived price unfairness, perceived negative transaction value, perceived loss in acquisition value, and internal reference price. The model was tested with a structural equations model. In experiment one, when the temporal distance was proximal, advertised selling price, which is a low level construal, was more influential on perceived loss in acquisition value. On the other hand, when the temporal distance was far, perceived quality, which is a high level construal, was more influential on perceived loss in acquisition value in line with predictions of construal level theory that assert high level construals are more influential at far but low level construals are more impactful at proximal temporal distance. Consumers perceived more price unfairness and negative transaction value when the post-purchase price reduction was proximal to their purchase than when it was far. In the high price reduction condition, consumers perceived higher perceived negative transaction value and higher perceived price unfairness than in the low price reduction condition. In experiment two, temporal distance moderated the relationship from advertised selling price to perceived negative transaction value such that advertised selling price was influential on perceived negative transaction value at proximal temporal distance but not at far temporal distance as expected by construal level theory.
Efficient Control Signaling for Resource Allocation in OFDMA Networks
Authors:   , Ku Gwanmo , Walsh John MacLaren
Published: July 2021

This thesis designs efficient control signaling for resource allocation in OFDMA networks, with special attention given to improving the resource controller in the LTE standard. We are interested in two aspects of resource controller design, the amount of control information a resource controller utilizes, and the performance, for instance the data spectral efficiency, it attains. Our overall aim is to understand the fundamental tradeoff between these two quantities, and to learn how to design resource controllers that approach this tradeoff. To get a sense of the state of the art in resource controller design, we first investigate the resource controller in the LTE standard, evaluating the amount of control information it requires. We thoroughly catalog the physical layer signals related to resource allocation and link adaptation with a focus on the location and formatting of the pertinent reference and control signals, as well as the decisions they enable. This enables us to determine the fraction of the time frequency resource grid spent on control information. This control signaling overhead in LTE occupies a large percentage of the time-frequency footprint of wireless network traffic and is not efficiently encoded. After this, we set about determining the fundamental tradeoff between the amount of control information and the spectral efficiency by modeling the problem using information theory. In order to design more efficient control signaling schemes, we will model the control signals as messages in a distributed lossy source code, for which the rate distortion function describes an optimum tradeoff between a rate, reflecting the overhead, and a distortion, reflecting the performance. Although there is no closed form expression for the rate region, we derive a novel adaptation of the Blahut-Arimoto algorithm to the CEO model with independent sources, and use it to numerically calculate the rate distortion function. The developed algorithm is then utilized to calculate the rate distortion function for a series of simple resource allocation models. Finally, for these physical layer resource allocation models, we design practical distributed quantizers that yield control signaling encodings for a resource controller that approaches the fundamental overhead performance tradeoff limit calculated.
Prospective Memory Acquisition in Multiple Sclerosis
Authors:   , McKeever Joshua D. , Schultheis Maria T.
Published: July 2021

Objective: Multiple sclerosis (MS) is associated with the presence of cognitive deficits. Prospective memory (PM), or "remembering to remember," has significant functional relevance to the MS population. Individuals with MS show mild-to-moderate deficits in PM, which have been associated with increased risk of dangers such as medication nonadherence. Research has yet to determine which aspects of PM are particularly problematic for individuals with MS, and whether impairments in cognitive constructs underlying PM may contribute to overall PM errors. Selective reminding, a novel methodology within PM research, was used to delineate the contributions of each stage within the process of PM to overall PM ability. Participants: Groups consisted of two samples of individuals with MS (2 conditions: SR, n=11 and 1T, n=10) and two samples of healthy controls (SR, n=13 and 1T, n=9). Groups were matched on distributions of demographic variables, and MS groups were matched on disease-related variables. Methods: Participants underwent a two-hour battery of testing. The main measure of interest was a novel measure of PM, the Selective Reminding PM (SRPM) task. Both diagnostic groups (MS and HC) were randomly assigned to two conditions: MS-SR (full SRPM task) and MS-1T (only one encoding trial provided). Additional variables collected included performance in several neuropsychological domains as well as demographic, psychosocial, and MS disease-related factors. Results: Data indicated that the participants in the SR conditions (vs. 1T conditions)demonstrated stronger PM performance in both MS and HC groups. Individuals with MS were impaired relative to HCs in the 1T condition, but performance was statistically equivalent between diagnostic groups in the SR condition. Conclusions: Overall, the current theoretically-driven examination of PM encoding in MS (as compared to healthy adults) provided intriguing and useful information about the process of PM in MS and the importance of the Intention Formation stage of processing. This project replicated previous findings (acquisition deficits) for PM in MS that have been well-established for retrospective memory in this group. These findings have significant implications for the cognitive psychology of PM and may also help provide guidelines for assessment and remediation of PM difficulties in MS and other populations.
Numerical simulation of chlorine disinfection processes in non-ideal reactors
Authors:   , Greene Dennis Joseph , Haas Charles N. , Farouk Bakhtier
Published: July 2021

The efficacy of disinfection processes in water purification systems is governed by several key factors including reactor hydraulics, disinfectant chemistry and microbial inactivation kinetics. The objective of this work was to develop a computational fluid dynamics (CFD) model to predict flow structure, mass transport, chlorine decay and microbial inactivation in a continuous flow reactor. The significance of this dissertation is that comprehensive 3D numerical model was developed to address all major components of the chlorine disinfection process in continuous flow systems (flow structure, mass transport, chlorine decay, microbial inactivation). Prior models have only predicted chlorine contactor flow structure and residence time distribution (Stambolieva et al., 1993; Hannoun and Boulos, 1997; Crozes et al., 1997; Wang and Falconer, 1998). Furthermore, the present model incorporates experimentally measured chlorine decay and non-linear microbial inactivation kinetics. The 3D, Eulerian-Eulerian model was implemented with a general-purpose commercial code (CFX4, AEA Technology) and executed on a personal computer (Windows® NT platform). Numerical predictions for tracer transport, chlorine decay and microbial inactivation correlated well with experimental measurements of Haas et al. (1995). The experimental program of Haas et al. investigated the kinetics of the chlorine disinfection process in a continuous flow pilot reactor for varying source waters, chlorine doses (free and combined) and microorganisms (E. coli, MS2 bacteriophage and Giardia muris. The CFD model yielded more accurate predictions of inactivation efficacy than the Integrated Disinfection Design Framework (IDDF) protocol (Bellamy et al., 1998) for the experimental data set. The numerical model demonstrates that inlet configurations can significantly affect reactor hydrodynamics, and that both mixing and kinetics affect disinfection efficiency. As such, both factors should be considered in reactor design for disinfection processes. The IDDF protocol relies on the assumption of complete segregation in real reactors and thus does not consider mixing effects. This assumption may lead to over- or under-estimation of disinfection efficiencies. The Eulerian-Eulerian model of this study does not rely on an assumption of mixing state and thus yields a better prediction of microbial inactivation.