Digital Commons Network^™

Two-Component Hydrogel As Biomimetic Vitreous Substitutes, Sruthi Santhanam

McKelvey School of Engineering Graduate Student Theses & Dissertations

The vitreous humor of the eye is a biological hydrogel principally composed of fibrillary collagen interspersed with semi-flexible polyelectrolyte, hyaluronic acid (HA). Certain pathological conditions necessitate its removal and replacement. Current vitreous substitutes, such as silicone oils and perfluorocarbons, are hydrophobic, do not resemble the properties of the vitreous, and have known complications. An ideal vitreous substitute should have properties of the natural vitreous, perform its functions, and be biocompatible in the eye. Inspired by the structure and composition of the natural vitreous, we used bio-mimicry to develop an injectable two-component hydrogel. The hydrogel is composed of a fibrillary gellan, …

Mechanics Of The Developing Brain: From Smooth-Walled Tube To The Folded Cortex, Kara Ellspermann Garcia

McKelvey School of Engineering Graduate Student Theses & Dissertations

Over the course of human development, the brain undergoes dramatic physical changes to achieve its final, convoluted shape. However, the forces underlying every cinch, bulge, and fold remain poorly understood. This doctoral research focuses on the mechanical processes responsible for early (embryonic) and late (preterm) brain development.

First, we examine early brain development in the chicken embryo, which is similar to human at these stages. Research has primarily focused on molecular signals to describe morphogenesis, but mechanical analysis can also provide important insights. Using a combination of experiments and finite element modeling, we find that actomyosin contraction is responsible for …

Regulation Of Gene Expression By Rna Binding Proteins And Micrornas, Kyle Cottrell

Arts & Sciences Graduate Student Theses and Dissertations

Regulation of gene expression is essential to life. Post-transcriptional regulation of gene expression is a complex process with many inputs that lead to changes in localization, translation and stability of mRNAs. The translation and stability of many mRNAs is regulated by cis-elements, such as mRNA-structure or codon optimality; and by trans-acting factors such as RBPs and miRNAs. Here I report on the complex interactions between RBPs, miRNAs and characteristics of their target mRNAs in respect to effects on translation and RNA stability.Using a reporter based approach we studied modulation of microRNA-mediated repression by various mRNA characteristics. We observed the influence …

Fast Monte Carlo Simulations For Quality Assurance In Radiation Therapy, Yuhe Wang

Arts & Sciences Graduate Student Theses and Dissertations

Monte Carlo (MC) simulation is generally considered to be the most accurate method for dose calculation in radiation therapy. However, it suffers from the low simulation efficiency (hours to days) and complex configuration, which impede its applications in clinical studies. The recent rise of MRI-guided radiation platform (e.g. ViewRay’s MRIdian system) brings urgent need of fast MC algorithms because the introduced strong magnetic field may cause big errors to other algorithms. My dissertation focuses on resolving the conflict between accuracy and efficiency of MC simulations through 4 different approaches: (1) GPU parallel computation, (2) Transport mechanism simplification, (3) Variance reduction, …

The Chemistry And Biology Of Iron-Scavenging Natural Products From Pathogenic Acinetobacter Baumannii, Justin Shapiro

Arts & Sciences Graduate Student Theses and Dissertations

Multidrug resistant (MDR) Gram-negative bacteria represent a global health crisis. Traditional antibiotics create selective pressure and breed resistance, making our current drugs less and less effective. Targeting of bacterial virulence factors has gained interest as an alternative strategy to potentially circumvent this problem. Virulent Acinetobacter baumannii synthesize and secrete pre-acinetobactin, a small molecule metal chelator that scavenges life-sustaining iron and is critical for establishing infection. The work described herein sheds light on the unusual properties of a non-enzymatic isomerization from pre-acinetobactin to acinetobactin and proposes a siderophore-swapping mechanism by which A. baumannii expands its pH window for virulence. Knowledge from …

Roles Of Peroxisomes And Peroxisome-Derived Products In Controlling Plant Growth And Stress Responses, Elizabeth May Frick

Arts & Sciences Graduate Student Theses and Dissertations

The peroxisome is a vital organelle conserved through the entire eukaryotic lineage. In all examined species, peroxisomes are responsible for such essential processes as fatty acid beta-oxidation and metabolism of reactive oxygen species (ROS). In plants, peroxisomes have taken on additional specialized roles, such as production of some plant hormones and vitamins. In this work, I have uncovered novel factors regulating peroxisome number in model species Arabidopsis thaliana, and novel mechanisms governing how peroxisomes respond to salt stress. I discovered a role for Arabidopsis MAP KINASE17 (MPK17) as a negative regulator of peroxisome division that acts in the salt-stress response …

Understanding The Paradox Of Genetic Diversity In Uropathogenic E. Coli: The Uncommon Evolution Of A Common Pathogen, Henry Louis Schreiber

Arts & Sciences Graduate Student Theses and Dissertations

Urinary tract infections (UTIs) are the second most common bacterial infection of people in the U.S.A and are frequently recurrent, as an initial UTI is quickly followed by a second episode in 30-35% of cases despite appropriate antibiotic treatment and clearance of the bacteria from the urine. The vast majority, >80%, of UTIs are caused by uropathogenic Escherichia coli (UPEC). UPEC that colonize the bladder are thought to originate in the gut, where they live as commensal organisms. UPEC can be shed in feces to colonize the vagina and/or periurethral area, and then can ascend into the bladder to start …

Functional Bio-Nano Hybrids Through A Precise Control Of Interfacial Interactions At The Nanoscale, Sirimuvva Tadepalli

McKelvey School of Engineering Graduate Student Theses & Dissertations

During the course of evolution, proteins have evolved to perform exquisite functions including structural support, signal transduction, actuation, sensing, catalysis, trafficking, gating, light-harvesting, charge transfer, molecular recognition, self-assembly, self-organization, or combinations of two or more of these functions. A precise control and manipulation of the structure and function of proteins is conceivable with the advent of nanotechnology, which has facilitated the integration of nanomaterials with functional biomolecules to realize bio-nano hybrids with synergistically enhanced functionalities.

At the genesis of bionanotechnology, a paucity in the fundamental understanding of the bio-nano interfaces is a grave impediment to the progress of the field. …

Bio-Inspired Multi-Spectral And Polarization Imaging Sensors For Image-Guided Surgery, Nimrod Missael Garcia

McKelvey School of Engineering Graduate Student Theses & Dissertations

Image-guided surgery (IGS) can enhance cancer treatment by decreasing, and ideally eliminating, positive tumor margins and iatrogenic damage to healthy tissue. Current state-of-the-art near-infrared fluorescence imaging systems are bulky, costly, lack sensitivity under surgical illumination, and lack co-registration accuracy between multimodal images. As a result, an overwhelming majority of physicians still rely on their unaided eyes and palpation as the primary sensing modalities to distinguish cancerous from healthy tissue. In my thesis, I have addressed these challenges in IGC by mimicking the visual systems of several animals to construct low power, compact and highly sensitive multi-spectral and color-polarization sensors. I …

Image Reconstruction Of The Speed Of Sound And Initial Pressure Distributions In Ultrasound Computed Tomography And Photoacoustic Computed Tomography, Thomas Paul Matthews

McKelvey School of Engineering Graduate Student Theses & Dissertations

Ultrasound computed tomography (USCT) and photoacoustic computed tomography (PACT) are two emerging imaging modalities that have a wide range of potential applications from pre-clinical small animal imaging to cancer screening in human subjects. USCT is typically employed to measure acoustic contrasts, including the speed of sound (SOS) distribution, while PACT typically measures optical contrasts or some related quantity such as the initial pressure distribution. Their complementary contrasts and similar implementations make USCT and PACT a natural fit for a hybrid imaging system. Still, much work remains to realize this promise. First, USCT image reconstruction methods based on the acoustic wave …

Development Of In Vitro Drug Screening Platforms Using Human Induced Pluripotent Stem Cell-Derived Cardiovascular Cells, Yosuke Kurokawa

McKelvey School of Engineering Graduate Student Theses & Dissertations

Drug-induced cardiotoxicity is a critical challenge in the development of new drugs. Since the advent of human pluripotent stem cell-derived cardiomyocytes (CMs), researchers have explored ways to utilize these cells for in vitro preclinical drug screening applications. One area of interest is microphysiological systems (i.e. organ-on-a-chip), which aims to create more complex in vitro models of human organ systems, thus improving drug response predictions. In this dissertation, we investigated novel analysis methods and model platforms for detecting drug-induced cardiotoxicity using human induced pluripotent stem cell (iPSC)-derived cardiovascular cells.

First, we utilized human iPSC-derived CMs (iPS-CMs) to establish optical methods of …

Moodboard: A Digital Solution For The Work-Life Balance In An Advertising Agency, Shalaka Shantaram Haldankar

Theses

The long working hours prevalent in the advertising industry is a well-known fact. It has become a common practice in agencies for quite a while now, leading to work-life imbalance for employees. The advertising agencies follow this practice, not because of its effectiveness, but because that’s what everyone else does. They completely ignore the fact that short breaks from work can increase productivity. A common belief of the industry is that the more nights/weekends you spend at work, the more productive you are. Research proves such work stress affects your personal life and health.

The goal of this thesis is …

Soundboard Scholar No. 3: Editor's Letter, Thomas Heck

Soundboard Scholar

An introduction to the contents of this issue.

The Way We Were: A Review Of Early Efforts To Find Classical Guitar Music In Collections, Ellwood Colahan

Soundboard Scholar

This article was originally copublished online with the author's article, "Guitar Music in Collections: A New Web-Based Index Is Launched," Soundboard Scholar, no. 3 (2017), https://digitalcommons.du.edu/sbs/vol3/iss1/6.

Life Being An International Student In The United States: Acculturation, Culture Shock, And Identity Transformation, Lai Yan Vivyan Lam

Master's Theses

The population of international students at community colleges in the United States has increased significantly over the past decade. International students play a big role in building the cultural diversity on campus by bringing over different cultures and sharing their global perspective to the local community. However, they often face challenges adapting into American culture due to cultural differences in education system, language, lifestyle, etc. By looking into the acculturation process of international students to analyze the culture shock and cultural identity changes they experienced, this paper intends to seek ways to help this group of students to ease their …

Afro-Latinx Transnational Identities: Adults In The San Francisco Bay And Los Angeles Area, Koby Heramil

Master's Theses

This paper examines the identity construction of Afro-Latinas/os/x in the San Francisco Bay and Los Angeles Area. Marginalized communities predominately Black and Latina/ o/x concentrated are at the epicenter of disenfranchisement caused by the globalization of neoliberalism. Neoliberal reforms to education restrain the various nuances of pluralistic teaching, focusing only on the performance of standardized tests thus pressuring schools to center their interest in securing funding. This has greater implications for low-income communities of color where multicultural pedagogy is limited. More importantly, this association of neoliberalism reforms to education affects Afro-Latinx individuals, because they are maligned in the conversation about …

The Resisters: Contemporary Ethiopia Through A Feminist Lens, Eldana Mathias Temesgen

Master's Theses

Based on the recent mass protests in Ethiopia, there is a strong indication that the Oromo people of Ethiopia, who are at the forefront of these protests, have been placed in a position of marginal importance, influence and power in their society. Due to the power and agency wielded by the government, some ethnic groups in Ethiopia, including the Oromo ethnic group, claim to be underrepresented on a political, economic, and social scale, which has led to conflict.

The nuances of ethnic based conflict, such as the situation in Ethiopia, have been tackled through several disciplines and examined through different …

Development Of Design Equations For Drilled Shafts In Granular Dense Soils Using Dem Simulations, Sadia Faiza

Civil Engineering ETDs

Drilled shafts have proven to be cost-effective, excellent performing, deep foundation systems where large loads and lateral resistance are major factors. The available design methods that are recommended by FHWA (2010) for drilled shafts are mostly empirical and are developed based on generalized data which sometimes can be conservative for a particular soil. The main objective of this study is to develop a design methodology for estimating the side resistance of an axially loaded drilled shaft based on the current and the unique properties of the soil. The objective was met through using the discrete element method (DEM) to investigate …

Title Ix In The Technological Age-Challenging Rape Culture And Myths Through Fairer Use Of Electronic Communications, Drew Simshaw

Tennessee Journal of Race, Gender, & Social Justice

No abstract provided.

Transgender Bathroom Rights In The Time Of Trump, Catherine Jean Archibald

Tennessee Journal of Race, Gender, & Social Justice

On May 13, 2016, the Obama Administration issued a guidance document entitled “Dear Colleague Letter on Transgender Students,” which interpreted federal law as requiring that transgender students be permitted to use bathrooms that correspond with their gender identity in schools receiving federal funding. Considerable litigation ensued. Less than a year later, on February 22, 2017, the Trump Administration rescinded this guidance document. The Trump Administration asserts that it should be up to individual states to decide what bathrooms transgender children may use in schools.

This article addresses where transgender bathroom rights stand now that Obama’s Dear Colleague Letter has been …

On The Same Team: Locker Room Talk, Student Athletes, And A Call For A Restorative Justice Approach To Sexual Assault Education, Brian A. Pappas

Tennessee Journal of Race, Gender, & Social Justice

No abstract provided.

Title Ix's Field Of Unrealistic Dreams: If You Build It, Will They Come?, Becky L. Jacobs

Tennessee Journal of Race, Gender, & Social Justice

No abstract provided.

Edward A. Ross: Social Development And Social Control, Ernest M. Oleksy

The Downtown Review: An Interdisciplinary Journal Written and Peer-Reviewed by Mandel Honors College Students at Cleveland State University

With a foundation in philosophy and history, core concepts of sociology and criminology that were initially posited over a century ago are still useful in understanding the workings of today's society. The contributions of Edward A. Ross have helped latter day researchers centralize their studies of polycentric topics by using social control as an omnipresent social fact. By comparing Ross's descriptions of 19th century society and the researcher's descriptions of 21^st century society, a continuous understanding of a heavily pluralistic discipline comes to life.

Standing And The Ninth Floor Again: The Military Hospital By Sghaier Ouled Ahmed, Hager Ben Driss

Transference

Translated from Arabic by Hager Ben Driss

Excerpts From The Clutter Of Words By Suzanne Alaywan, Nina Youkhanna

Transference

Translated from Arabic by Nina Youkhanna

Transference Vol. 5, Fall 2017

Transference

No abstract provided.

Contributor's Notes

Fishladder: A Student Journal of Art and Writing

No abstract provided.

Disguise, Stephanie Mabie

Fishladder: A Student Journal of Art and Writing

No abstract provided.

Contributors, Antipodes Editors

Antipodes

No abstract provided.

Recommending Items For Deletion Based On Item Quality And Usage, N/A

Defensive Publications Series

Generally, the present disclosure is directed to recommending items stored in a data storage system for deletion. In particular, in some implementations, the systems and methods of the present disclosure can include or otherwise leverage one or more machine-learned models to predict a likelihood of deletion for an item based on item data and user interaction data for one or more items.