Electronic Theses and Dissertations

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About: Electronic theses and dissertations (ETDs) are the graduate research outputs of Texas Tech University. They represent years of work from our Master's and Doctoral graduates. If you find the ThinkTech digital repository useful, please tell us! Share how open access to scholarship benefits you. Your story matters to us.

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1,25-dihydroxyvitamin Db3s gut receptor kinetics in Japanese quail and vitamin D metabolism in calcium-depleted rats
(Texas Tech University, 1981-08) Abel de la Cruz, Luis Andres
Not available
1-D Fourier Ptychographic Microscopy
(2017-05) Alotaibi, Mohammed; Grave de Peralta, Luis; Bernussi, Ayrton
Fourier Ptychographic Microscopy (FPM) is a novel and promising phase-recovery imaging technique that can surpass Rayleigh resolution limit when imaging non-periodic samples. However, we show that in photonic crystal imaging applications the resolution limit of the FPM technique cannot surpass Rayleigh resolution limit. We present a comprehensive discussion of this loophole in the FPM technique and we discuss how this limitation can be overcome
10-K Speed: Is focus on the financial reporting function associated with better accounting information?
(2023-08) Ryan, David; Oler, Derek; Haislip, Jacob; Myers, Brett
This paper examines the association between focus on the financial reporting process as indicated by 10-K filing speed and the quality of accounting information as assessed by the accuracy of initial, annual earnings per share forecasts. I find a significant, inverse relationship between the speed of the 10-K filing and management forecast error. Firms that accelerate filing over time demonstrate an improvement in the accuracy of their earnings forecasts relative to firms that do not. Analyst forecasts are significantly influenced by management forecasts, but results do not suggest a significant, direct relationship. These findings contribute to the financial reporting, management forecast error, and management accounting literature by identifying a link between the external and internal information systems and the associated internal information environment.
12 Preludes by Edward R. Nelson: Compositional and Interpretative Analysis
(2023-12) Guelfand, Jonathan B.; Sukhina, Nataliya; Martens, Peter A.; Fischer, Peter
This document is a musical analysis of 12 Piano Preludes by Edward Robert Nelson, a contemporary American living composer. The scope of this analysis includes compositional devices of the piece (such as harmony, counterpoint devices, thematic treatment and formal considerations) as well as an interpretative guide for the pianist. I will link the latter to the former since, in addition to possessing an individual artistic vision of a piece, the performer should succeed in showing the different musical aspects inherent to it. In relation to the analysis, I will provide an interview with Dr. Alex Bui, a pianist who has performed Nelson’s music and is currently studying the 12 Preludes. I have established a relation between the chosen pieces and romantic pianism; therefore the document includes a brief chapter studying the romantic piano prelude as a genre. I will also include a biography of Mr. Nelson, together with the history behind the composition of these preludes. As far as the analysis concerns, I will show aspects pertinent to the preludes both individually and as a set, including a study of the inter-relation between the first and the last piece, an intentional device by the composer.
1967: The year that created ‘68 media perspectives and student outcries
(2011-05) Strong, Ryan R.; Wong, Aliza S.; D'Amico, Stefano; Fallwell, Lynne A.
In 1967, Italian students developed the principles and practices that led to the monumental events of '68. Students occupied faculty buildings and demonstrated in the streets of major Italian cities. Following every events local, national and political newspapers reported to their readers a very well thought out perspective. The perspective given to the reader was the major way many Italians learned of the Italian student movement. Therefore, newspapers played a major role in the perceived memory of sessantotto in the minds of Italians.
1:1 technology initiative: A case study to determine the barriers of implementation in a rural school setting
(2012-12) Barnett, Shaun; Klinker, JoAnn F.; Duemer, Lee S.; Brown, Wendell J.
The purpose of this qualitative study is to explore the decisions necessary for superintendents of small rural schools who desire to implement a 1:1 technology initiative. Superintendents have an ethical obligation to their staff, their students, and to all stakeholders of the district, to use their resources wisely, to think outside of the box, and to create an environment that allows for the integration of technology into the curriculum. When implementing a 1:1 technology initiative, many barriers present themselves that must be considered when determining the path toward a 1:1 initiative. This study will center on the characteristics of transformational leadership that are exhibited by the superintendents being studied and the ethical decisions that are necessary when undertaking such an initiative. A superintendent, using transformational leadership with an ethical focus, must work to overcome the barriers associated with implementing a technology initiative. They must be leaders with a truly visionary approach to the future successes of their students and their schools. The literature reviewed for this study showed a consistent purpose for administrators to develop procedures for the implementation of technology into the school setting. The integration of technology into the school setting helps transform schools into an environment of learning by doing instead of a system of merely absorbing knowledge (Collins & Halverson, 2009). Further research is needed in the areas of financial considerations, appropriate professional development, and the impact a 1:1 initiative will have on high-stakes testing accountability.
[2+2] Cycloaddition Reactions of Bestmann’s Ylide with Imines
(2023-08) Katakam, Nanda Kumar
Organophosphorus compounds are useful reagents in synthetic chemistry and biochemistry with applications ranging from small molecule synthesis to polymers and pharmaceutical intermediates. A notable example of such organophosphorus reagents is Bestmann’s ylide, (Ph3P=C=C=O), a phosphonium ylide with cumulated double bonds. In addition to be utilized as a linchpin reagent in the synthesis of various natural products, it is capable of undergoing various [2+2], [2+3] and [2+4] cycloaddition reactions. Herein, we report new cycloaddition reactions of Bestmann’s ylide with a wide range of imines to give new β-lactams and acrylamides. Bestmann’s ylide reacts with various N-Cbz/N-Boc imines to selectively form β-lactams with exocyclic phosphonium ylide functionalities, which can react with various aldehydes to undergo Wittig reactions to give β-lactams with exocyclic double bonds under mild reaction conditions. On the other hand, Bestmann’s ylide can also undergo [2+2] cycloaddition with the N-tosyl imines to undergo a formal [2+2] cycloaddition, followed by a new ring-opening reaction to produce isolable triphenylphosphonium zwitterions. These zwitterionic species can be subjected to Michael addition at the β-carbon to selectively form amides with reactive α-phosphonium ylide moieties, which upon addition of selected aldehydes undergo Wittig reactions to give α-substituted acrylamides in good to excellent yields.
2-Methoxyestradiol, a novel pharmacological inhibitor for Angiotensin Type I Receptor
(2012-05) Koganti, Sivaramakrishna; Thekkumkara, Thomas; Abbruscato, Thomas J.; Karamyan, Vardan; Liu, Xinli
Delayed onset of cardiovascular(CVD) disease among females is not well understood, but could be in part due to the protective effect of estrogen before menopause. Experimental studies have identified the angiotensin type I receptor (AT1R) as a key factor in the progression of CVD.In this study, we have examined the effects and mechanism of the estrogen metabolite, 2-Methoxyestradiol (2ME2), on AT1R expression.The study used rat liver epithelial cells as the primary cell model to determine the 2ME2 induced cellular signaling, the overall concept was further confirmed in rat aortic smooth muscle cells and further validated in vivo in an animal model of hypertension. When rat liver epithelial cells were exposed to 2ME2 for 24 hours, cells exhibited significant down-regulation of AngII binding and AT1R mRNA, independent of estrogen receptors (ERα/ERβ) with no change in receptor affnity.Significant inhibition of AngII mediated increase in intracellular Ca+2 and increased phopsphorylation of ERK1/2 were also observed.Similar analyses in stably transfected CHO cell lines with a constitutively active cytomegalovirus (CMV) promoter showed no change in AT1R expression suggesting the transcriptional regulation.2ME2 has been shown to bind specifically to endoplasmic reticulum bound G-protein coupled receptor 30(GPR30), activating matrix metalloprpteinases (MMPs) to induce epidermal growth factor receptor (EGFR) activation ultimately leading to AT1R down-regulation.2ME2 treatment showed significant down-regulation of systolic, diastolic and mean arterial blood pressure, as well as a decrease in body weight in spontaneously hypertensive rats (SHR).Consistent with the reduction in blood pressure, we observed AT1R protein and mRNA expression down-regulation in the renal cortical tissue. In summary, as AT1R plays a critical role in the control of cardiovascular diseases, 2ME2 induced changes in receptor expression may provide beneficial effects to the cardiovascular, as well as other systems.
2015 and 2018 National Meat Case Studies: Packaging type, marketing claims, and allocation in the self-service meat case
(2021-08) Mills, Benjamin Isaac; Miller, Markus F.; Woerner, Dale R.; Legako, Jerrad F.
Stores from across the United States were audited to determine the frequency of common packaging types, tray types, tray colors, marketing, and allocation of space of meat and non-meat items in the meat case. 108 stores in 25 states were visited and surveyed in 2015 whereas in 2018 150 stores were audited in 31 states. Auditors were trained by Cryovac Inc. employees at the Gordon W. Davis meat science laboratory before auditing. States were subdivided into 5 regions based on geographical area: West Coast, Mountain/ Southwest, Midwest, Southeast, and Northeast. Store were audited based on stock keeping units (SKUs) as each SKU represents a unique item in the meat case. Data were analyzed by comparing across species of beef, ground beef, pork, turkey, chicken, veal, lamb, and in 2018, seafood. Additionally, case length was recorded to determine allocation of the retail space to various species groups. In addition, the species groups above, non-meat items, value added products, sausage, processed meat, and miscellaneous were categorized and compared for the percentage allocation of the retail case. Poly-vinyl chloride packaging was the most popular in 2015 and 2018 making up 43.4% and 42.8% of the meat case, respectively. Laminate packaging was the second most popular packaging type at 16.9% and 17% in 2015 and 2018, much more than in previous studies. Tray-less packaging has increased significantly over the years reaching 29.5% of all packaging. White trays are found in the highest percentage of the meat residing around 32% of all packaging types. Black colored trays have decreased in frequency from 2007 to present making up only 19% of the meat case. Yellow tray packaging, however, is the popular tray color for chicken at 37.2%. Chicken was the only species group found in all stores in both 2015 and 2018 while beef decreased its presence in the meat case from 100% to 98% from 2015 to 2018. Space allocated to beef shrunk by an average of 1 meter per store between 2015 and 2018. In both years, chicken was allotted the greatest amount of space in the retail case at 16 meters per store. Beef controls the majority of SKUs offered in the meat case at approximately 30% of all SKUs in 2018. The space provided to each SKU in the meat case shrunk between 2015 and 2018 to only 0.39 meters per SKU average.
26,27-Dehydrolanosterol and Cholesta-5,7,22,24-tetraenol are suicide substrates of sterol methyl Transferase in Acanthamoeba castellanii
(2017-05) Kidane, Medhanie E.; Nes, William David; Shaw, Robert W.; Zhou, Wenxu
Acanthamoeba castellanii (AC) is a pathogenic protozoan that causes blinding keratitis in humans. AC synthesizes C28 ergosterol while humans synthesize C27 cholesterol. The one carbon difference at C24 in the sterol structures of parasite and host is generated by sterol methyl transferase (SMT). In an effort to understand the mechanism of action of suicide inhibitors designed to inhibit sterol methylation that thereby prevents ergosterol biosynthesis and growth, 26,27-dehydrolanosterol (DHL) and cholesta-5,7,22,24-tetraenol (T4) were evaluated against cloned AcSMTs. During the course of the investigation, two AcSMTs were identified through bioinformatic and chemical analyses of the ergosterol biosynthetic pathway, one of them (24AcSMT) was shown to covert cycloartenol to 24(28)-methylenecycloartanol while the other one (28AcSMT) was shown to convert 24(28)-methylenelophenol to 4α-methyl 24β-ethylstigmasta-7,25(27)-dienol and other minor products. To determine the specificity of DHL and T4 as suicide inhibitors of 24AcSMT or 28AcSMT, a series of kinetic and chemical experiments were carried out against the cloned enzymes. Based on GC-MS analysis of enzyme generated methyl sterol diol formation, DHL inactivated 24AcSMT while T4 inactivated 28AcSMT. Based on steady-state kinetic analysis, DHL generated Ki values of 16µM against 24AcSMT and 40µM against 28AcSMT, while T4 generated Ki values of 18µM and 8µM respectively. Consistent with suicide behavior, DHL showed time-dependent inactivation properties against 24SMT exhibiting kinact of 0.04min-1 and the 3H-DHL intermediate-24SMT complex co-migrated with wild type Ac-24SMT on SDS-PAGE gel. The results show that DHL and T4 are potential therapeutic leads in the design of next generation drugs to treat amoeba infections.
3-D modelling and classification in automated target recognition
(Texas Tech University, 1990-08) Nutter, Brian
Automated target recognition (ATR) using a computer vision system is a problem of extremely high complexity. A 3-D object recognition scheme involves many image analysis and enhancement techniques, including image processing, image segmentation, image registration, and object modeling and projection. This dissertation addresses the problem of 3-D object recognition using five distinct methods of matching image data with model projection-derived data. In analyzing each digitized video image, a variety of techniques, including an optimal gray level map for correlating binary line drawings with gradient images, were used to enhance the visibility of particular features and to increase signal to noise ratios in images. The shapes extracted from these enhanced images were then analyzed in a number of fashions, including the statistical descriptors of Karhunen-Loeve transformation. The first of the five object identification methods which were tested compared descriptors of the object to be analyzed with those of model projections meeting certain criteria. The second compared the object descriptors to those of a precalculated series of model projections. The third method used the descriptions of the second method as a starting point for a neural network, and then proceeded to learn the differences between these model projections and actual data. The neural net as realized demonstrated a great reduction in training time over conventional implementations. Calibration difficulties of other methods were greatly reduced by the learning capability of the neural net. The fourth method cross-correlated the optimally mapped gradient of the object image with a series of model projections. Finally, ways of combining these methods to utilize the strengths of each were investigated. Superior accuracy was obtained for cross-correlation. Optimal techniques which significantly reduced the number of required correlations and hence the computational load were also found to give very accurate results.
3D augmented reality for medical application
(2016-05) Dang, Duc Tran Minh; Nutter, Brian; Mitra, Sunanda
Augmented Reality (AR) is a technology that augments user reality with computer-generated data such as GPS, audio, video or 3D objects. In comparison with virtual reality (VR), where the user’s view is totally replaced with a computer-generated environment, Augmented Reality focus on enhancing user’s reality experience with superimposed information. The application of Augmented Reality not only focuses on military and advertisement applications but also on education and medicine. This thesis focuses on development of an Augmented Reality application on the Android platform to view computerized axial tomography (CAT) scan images and 3D atlas models superimposed over the physical world, displayed on the device screen in real time. The developed application is based on AndAR framework, a Java API that provides a foundation to develop Augmented Reality projects on the Android platform.
3D Food Printing for Personalization: Design Space for Printability, Food Mechanics, and Consumer Ratings
(2023-05) Chirico Scheele, Stefania; Egan, Paul; Binks, Martin; Christopher, Gordon; Ertas, Atila
Additive manufacturing enables the production of complex structures with emerging approaches showing great promise in the food industry for design customization and personalized nutrition. 3D food printing uses soft ingredients that are automatically deposited using a layer-by-layer build process to form pre-specified edible shapes. Research in three-dimensional (3D) food printing has grown exponentially in recent years, however, producing and designing extrudable food materials that enable customized shape fabrication and retention remains challenging due to the complexity of food matrices and the need to satisfy consumer expectations for nutrition, texture, and taste. Previous studies have analyzed the rheological and textural properties of non-printable materials when using additives such as starches and gums to improve printability by improving the food mechanics. However, few studies have investigated the use of other types of additives that not only improve printability but also consumer ratings and nutritional profile. Past studies have demonstrated positive consumer perceptions of 3D food printing, but there is still a need for consumer validation of the technology through consumption and rating of fabricated 3D printed samples. Therefore, a design space between materials, food mechanics, and consumers' acceptance are presented in this dissertation. The studies aim to explore the 3D food printability of various design features and assess how well they print through quantitative and qualitative measurements; measure consumer response to design complexity, taste, and print fidelity; and investigate the effect of various additives on the printability, food mechanics, and consumer ratings when using various food base materials. This research leads to new contributions primarily across mechanical engineering and manufacturing, while also having implications for consumer studies. New findings would drive human-centered design research forward, particularly by including the consumer as an active participant rather than a passive selector of designed products. Continued industry adoption of design for 3D printing has the potential to promote the creation of customizable foods that bypass the one-size-fits-all approach of bulk manufacturing, while delivering healthier and more desirable foods for consumers.
3D Printed Microfluidics for Cancer Cell Isolation and Sepsis Detection
(2023-05) Yang, Yijia; Pappas, Dimitri; Gamez, Gerardo; Korzeniewski, Carol
Microfluidic cell separation techniques have gained significant attention in the field of clinical analysis due to their ability to perform high-throughput separations on small sample sizes. The use of microfluidic separation in clinical analysis offers several advantages, including the ability to perform high-throughput separations with small sample sizes, high sensitivity and specificity, and low cost. These benefits make microfluidic separation a promising tool for the advancement of clinical analysis and disease diagnosis. In this dissertation, Chapter I discusses the detailed fundamentals introduction of microfluidics. Chapter II and Chapter III present the studies of biomarkers used for cancer cells isolation and the application combined with affinity 3D printed microfluidic devices. Chapter IV discusses the study of biomarkers used in the early detection of sepsis and the application combined with 3D printed multi-zone microfluidic device in a clinical study. In Chapter V, the conclusion and prospects for the future are discussed. Cancer is a group of diseases characterized by the uncontrolled growth and spread of abnormal cells. Cancer cells typically grow quickly, are immature, and are unable to carry out the duties of healthy cells. The mortality of cancer patients will decrease if the cancer prognosis can be identified early (before a disease starts to metastasis). The selection of a biomarker for early cancer detection is crucial. In Chapter II and Chapter III, CD71 and EpCAM are used as cancer biomarkers with our 3D printed microfluidic device to isolate cancer cells. Capture purity and enrichment factor are being studied, in Chapter II, clinical cancer cells were spiked into blood and isolated with breast cancer samples having a purity of 93 ± 6% to 94 ± 10% and an enrichment factor of 1860 ± 120 to 1890 ± 190 and acute lymphoblastic leukemia samples having a purity of 90 ± 10% to 96 ± 7% with an enrichment factor of 1793 ± 200 to 1920 ± 140. The severe and sometimes fatal condition known as sepsis is brought on by an unchecked immunological reaction to infection. Sepsis must be identified and treated as soon as possible to lower the risk of serious consequences and enhance patient outcomes. In Chapter IV, we present a 3D multi-zone microfluidic device provided high sepsis capture purity and high enrichment factor. Anti-CD25, anti-CD64, and anti-CD69 were used as affinity cell capture biomarkers. The performance of our 3D printed multi-zone microfluidic device was assessed in this study, which included 35 septic patients and 10 healthy volunteers. With an AUC of 0.992, we discovered that our combination of anti-CD25, anti-CD64, and anti-CD69 antibodies worked well together to detect sepsis. According to the clinical validation, our multi-parameter microchip provides a potent sepsis assay for clinical point-of-care (POC) applications.
3D printing of double-network hydrogels
(2015-05) Zhang, Yajie; Qiu, Jingjing; Cho, Hanna; Lillian, Todd
In the project, we modified our 3D printer for printing hydrogel. The crosslinking of AAm and MBAA is soft and ductile which is suitable for artificial cartilage. Computer-aided design software was applied to geometry modeling. Compared to traditional sol-gel closed molding method, 3D printing is speedy, controllable and economical. 3D printing is more efficient in sol-gel phase transition. Tensile strength results shows that the samples manufactured by closed molding method and 3D printing method are satisfied. In order to improve the precision, sodium alginate was added to tune its rheological properties. Further more, the existence of alginate increases the strength and toughness but decrease the swelling rate, for the long chain polymer alginate tightens the structure. When treated with CaCl2, the ionic crosslingking further enhance the strength and toughness due to the increasing of crosslinking density. In general, 3D printing hydrogel is successful and this new method can be developed to tissue engineering.
3D simulation of manual material handling tasks based on nonlinear optimization method
(Texas Tech University, 2005-08) Zhang, Yanxin; Hsiang, Simon M.; Smith, James L.; Ayoub, Mohamed M.; Ekwaro-Osire, Stephen; Dayawansa, Wijesuriya P.
Two biomechanical approaches were launched in this study to simulate and investigate the manual material handling (MMH) activities. The first is a biomechanical simulation approach. In this approach, an inverse kinematics computation with nonlinear optimization method was applied to simulate MMH. Mathematically, the approach was expressed as a system of nonlinear equations with an objective function and a set of constraints, which was solved using an iterative numerical algorithm. The second is a dynamic & control approach. In this approach, the human body was viewed as a two-link rigid body (upper body and lower body) control system, which can control the muscles to generate different joint torques (ankle torque and hip torque) to compensate the external load moment which was be considered as a perturbation at different phase and posture during lifting. The body postural responses to a wide range of perturbations were simulated. To test and validate these two modeling approaches, a factorial experiment was conducted to obtain the kinematics data for different task conditions. A set of kinematics (angular displacement and angular velocity) and kinetic parameters (joint torque and compressive forces) was analyzed. The experiment results showed that the simulated data fit well with the experiment data and further insights of the human control strategy of MMH were gained by statistical analysis.
40 developmental assets: A comparison of retrospective reports between sexual minority and majority adults
(2014-05) Heath, Cody; Ivey, David; Smith, Douglas; Prouty, Anne; O'Boyle, Michael
There is currently a dearth in the research examining resiliency among self-identified Gay, Lesbian, Bisexual, and questioning youth. Demonstration of risk behaviors, mental illness, and negative peer interactions among sexual minority youth is highlighted in the current literature. These inherent risks in behavior, social interactions, and mental health are suggested to be much more pronounced in the GLB population when compared to the Straight or sexual majority population. This study examines the comparative resiliency attributes among the sexual majority and minority groups. By examining resiliency, risk is highlighted. Data from 111 sexual majority participants and 42 sexual minority participants were collected via an online survey. The results indicated no significant differences on internal or external measures of resiliency between the sexual majority and minority groups. Limitations and conclusions are discussed.
41BX274: Data Collection of Remote Sensing Anomalies and the Jacal Structure at the Perez Ranch in Bexar County, TX
(2017-05) Walter, Tamra; Jordan, MIchael
Data collection was carried out at the Perez Ranch Site (41BX274), which is located on the Medina River in the southwestern portion of Bexar County, Texas. Initially, the land was owned by the Mission San Jose y San Miguel de Aguayo. However, due to secularization of the church and ranching operations in the late 18th Century, this land was sold to Juan Ygnacio Perez. Perez was a direct descendant of Spanish settlers, and was married to the granddaughter of Andres Hernandez, the first private rancher in Texas. Perez was well known for supporting the Spanish crown and for his role in the Battle of Medina. Although the property was officially granted to Perez by Colonel Antonio Cordero in 1808, Perez had been occupying the land since 1793. Previous archaeological investigations, conducted by the Center for Archaeological Research, uncovered the stone foundation of the Perez family house, while archival records indicated that the ranch had 5 jacals and several corrals during its occupation by the Perez family. The current project was conducted from March 14th to March 22nd, 2015, and was headed by Jonathan Welch, a master’s student in the Anthropology department at Texas Tech University, and excavated by volunteering students from the Texas Tech Anthropology Department. The project will be divided into two areas in order to assess different questions about the site. Area A will be located approximately 8m east of the previously excavated stone house foundation. The purpose of Area A is to determine the cause of the anomaly that was found in both the GPR and Magnetometer Surveys conducted by the THC during the previous excavations. In order to assess this anomaly, a 2m by 2m unit will be placed where the anomaly is the most intensely observed. Area B will be located to the 25-30m southwest of the stone house and consists of one of the five jacal structures discovered by previous investigations. The purpose of the excavations in Area B will be to determine the construction methods and age of the jacal as well as determine the occupational sequence of the jacal, by placing units inside the jacal, as well as one on the eastern side of the jacal.
500 Throckmorton: A critically regional response to high-rise design
(2003-05) Peters, Michael G.; Haq, Saif; Benefiel, Aaron
The creation of an amalgam that would represent the design principles of both regionally sensitive and modernist architecture within the context of a downtown area can be accomplished using Critical Regionalism.
806HUB: An experiment in suburbia
(2006-12) Wahlberg, Jeremy Christopher; Robertson, Stanley Andrew; Buelinckx, Hendrika
Not Available

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