Digital Commons Network^™

Automated Fluid Handling And Leveling System For Multiple Material Stereolithography, Yinko I. Grajeda

Open Access Theses & Dissertations

This work addresses the development of an automated multiple material fluid handling and leveling system for its implementation into a Multiple-Material Stereolithography (MMSL) apparatus. A patent filed by Wicker et al. (US Patent 7,556,490) disclosing a MMSL apparatus served as the basis for the development of this work. The system is designed to operate in a variety of MMSL apparatus configurations. Fluid vats are designed to meet the enclosure constraints, facilitate the interface to the pump and sensor, and support the handling of the fluids. Due to its fluid isolation and bi-directional flow capabilities, a digital drive peristaltic pump is …

Ecology And Genetics Of Philodina Megalotrocha (Rotifera, Bdelloidea) From Chihuahuan Desert Populations, Lina Kamel Hamdan

Open Access Theses & Dissertations

The Chihuahuan Desert is a unique region with high biodiversity. There is a high degree endemism of freshwater biota, but relatively few studies have been focused on zooplankton. Bdelloid rotifers are one component of these ecosystems and often dominate very temporary habitats. Bdelloids are usually assumed to be cosmopolitan species due to their potentially high dispersal rates. Distribution records of the bdelloid P. megalotrocha extend from North America to New Zealand. However, little is known about its ecology or genetics. The aims of this study are to: 1) determine whether the distribution of P. megalotrocha in the Chihuahuan Desert is …

The Relationship Between Soft Body Composition And Bone Mineral Density In Premenopausal Hispanic And Caucasian Women, Clarelouise Anita Highfield

Open Access Theses & Dissertations

Investigating the relationship between soft body composition and bone mineral density of premenopausal Hispanic and Caucasian women may help in determining strategies to lower the risk of osteoporosis in postmenopausal women. PURPOSE: To investigate the relationship between BMD and soft tissue body composition, including lean mass and fat mass, of premenopausal Caucasian and Hispanic women. METHODS: Participants were 76 Hispanic [mean ± SD age: 42.7 ± 4.6 y; ht: 161.3 ± 5.66 cm; body mass: 70.14 ± 15.09 kg; BMI: 26.92 ± 15.09 kg/m2] and 46 White [age: 43.8 ± 4.3 y; ht: 165.5 ± 6.16 cm; body mass: 66.37 …

A New Photochemical Method For The Preparation Of Amino Acid-α-Phenylthioesters And Peptide-α-Phenylthioesters, Tyrone Hogenauer

Open Access Theses & Dissertations

We describe the development of a novel resin with a photoreactive N-acylnitroindoline linker that allows for the synthesis of amino acid- (in solution) or peptide-α-thioesters using standard Fmoc/t-Bu standard solid phase peptide synthesis (SPPS). Recent advances have shown that the yields of this thioesterification reaction have dramatically increased due to a simple change in the order of addition of reagents. Upon illumination with UV-light, in the presence of N-hydroxybenzotriazole (HOBt), the amino acid- or peptide-α-OBt ester is generated by direct photo-release from the nitroindoline linker with minimal epimerization, followed by reaction with thiophenol in the dark to produce amino acid-α-phenylthioesters …

Developmental Variation In Children's Acquisition Of Metrical Structure: How Early Treatment Of Stressless Syllables Can Inform Phonological Theory, Clifford S. Jones

Open Access Theses & Dissertations

The present study uses 26 color photos to elicit a total of 14 words conforming to a very specific pattern: a stressless syllable word-initially, followed by a stressed syllable, and at most one more stressless syllable. This was found to be a particularly difficult metrical structure for the two- and three-year old participants to produce in an adult-like manner. Based on the findings that a fairly reliable (if language-particular) order of acquisition is observable for contrasts of both place and manner of articulation, the case is made for a system of six emergent features, which may be characterized as combinable …

Awareness And Knowledge Of Hiv/Aids Among Female Indian University Students In South India And As Immigrants In The U.S.-Mexico Border Region, Thenral D. Mangadu

Open Access Theses & Dissertations

ABSTRACT

The prevention of HIV/AIDS is a major global public health goal. The Joint United Nations Programme on HIV and AIDS (UNAIDS) estimates that 33 million individuals are infected with HIV worldwide and over two million of these cases are from India. The main mode of transmission of HIV in India is heterosexual contact.

In the past decades there has been a steady increase in immigration rates from India to the U.S. Education and marriage are the main reasons for immigration from India to the U.S. In general, the frequently risky sexual and substance use behaviors of college students in …

The Literary Fictioning Of John Gregory Bourke's Imperial Nostalgia, Toni K. Mcnair

Open Access Theses & Dissertations

Nineteenth-century Army Captain and American ethnographer John Gregory Bourke (b. 1846 - d. 1896) meticulously described and documented a vast amount of information on military life, geography, ecology, and people on both sides of the Mexican-American border, offering observations and opinions of American, Mexican, Mexican-American, Apache, Pueblo, Zuni and Plains Indian cultures. Because of his ethnographic studies of Mexican-Americans along the Rio Grande, cultural studies scholars, José E. Limón and José David Saldí­var have identified John Gregory Bourke as complicit in the U.S. government's imperialist project. Referring to Renato Rosaldo's anthropological theory of imperialist nostalgia, These authors declare Bourke's work …

Ecological Study Of Oxygen Consumption In Three Species Of Rattlesnake, Crotalus Atrox, C.Lepidus And C. Molossus (Viperidae) From The Northern Chihuahuan Desert, Luis Miranda

Open Access Theses & Dissertations

The purpose of this study was to compare oxygen consumption of three species of rattlesnakes, Crotalus atrox, C. lepidus and C. molossus, that inhabit the Chihuahuan Desert within the Indio Mountain Research Station (IMRS), Hudspeth County, Texas. The resting metabolic rates (RMR) of 39 rattlesnakes (C. atrox, N = 17; C. lepidus, N = 8; and C. molossus, N = 14) were determined at four experimental temperatures (20°, 25°, 30°, and 35°C). The body masses ranged from 47 to 660 g for all three rattlesnake species.

The temperature coefficient of metabolism (Q10) averaged 2.8 between temperatures of 20°-30°C and 2.15 …

Embodied Cognition As Refutation To Langer's "Illusory Powers": "I Move, Therefore, I Know", Ruby Amanda Montana

Open Access Theses & Dissertations

Thesis Objective: To refute Susanne Langer's notion within her philosophy of dance which holds that emotional forces in dance are solely "virtual" and thus illusory. I plan to do so by means of the growing research in the branch of cognitive science known as Embodied Cognition.

In Brief: Susanne Langer, one of the most prominent philosophers of Aesthetics, contends that dance is able to express emotions as an external force, while creating what she calls a "primary illusion". Langer attributes gesture as the basic abstraction whereby the dance illusion is made and organized. Furthermore, she contends that dance is not …

A New Green Chemistry Method Based On Plant Extracts To Synthesize Gold Nanoparticles, Milka Odemariz Montes Castillo

Open Access Theses & Dissertations

Extraordinary chemical and physical properties exhibited by nanomaterials, as compared to their bulk counterparts, have made the area of nanotechnology a growing realm in the past three decades. It is the nanoscale size (from 1 to 100 nm) and the morphologies of nanomaterials that provide several properties and applications not possible for the same material in the bulk. Magnetic and optical properties, as well as surface reactivity are highly dependent on the size and morphology of the nanomaterial. Diverse nanomaterials are being widely used in molecular diagnostics as well as in medicine, electronic and optical devices. Among the most studied …

What Motivates Young Latina Females Along The U.S. Mexico Border Region To Participate In Team Sports?, Dora A. Pichardo

Open Access Theses & Dissertations

Physical activity gives women and girls an overall better quantity of life and positive health benefits. Statistics indicate lack of participation in physical activity and exercise by the U.S. general population and among the Latino population in particular. The primary purpose of this study is to explore the variables that motivate young Latinas to play and eventually continue to stay involved in team sports. This is a survey correlational study including young Latina females a U.S.-Mexico border community. Statistical analysis included frequencies, means, and Pearson Product Momentum Correlations. Sixty-nine participants (12 to 15 years old) completed the survey. The response …

Theoretical Exploratory Investigation On Reliability Of Advanced Ceramics By Discrete Element Simulation, Ana Laura Quezada Lara

Open Access Theses & Dissertations

The increasing application of silicon nitride in biomedical and other engineering fields has elevated the necessity to understand its reliability. Due to the complexity of producing pure material researchers have been analyzing the behavior of the material with flaws. In this thesis several scenarios are simulated with the support of PFC2D to analyze microcrack propagation depending on the position, quantity and size of the voids to understand the effect each of the cases have on the material. A four point bending test was applied to each case twice recording the loading force. Having two runs allows doing a statistical analysis …

Understanding The Promotion Effect: A Density Functional Theory Study Based On High Resolution Transmission Electron Microscopy Images For Mos2-Cobalt Promoted Interfaces, Manuel A. Ramos

Open Access Theses & Dissertations

Many studies had been done in order to understand promotion effect and structure/function in unsupported catalyst. Results indicated that d-electrons play an important role promoting catalytical active sites at the edges of MoS2 catalytically structures. Sulfur removal from crude oil, occurs on the edge of molybdenum di-sulfide (MoS2) nano structures, due to promotion of MoS2 nano structures with nickel or cobalt in sulfur-terminated or molybdenum-terminated edge planes. The promotion leads to formation of so-called CoMoS phase (MoS2/Co9S8) first discovered by meaning of Mössbauer spectroscopy, much more CoMoS phase usually called unsupported catalytical particles, have been topic of great interest in …

Fabrication Of Miniature Drug Screening Platform Using Low Cost Bioprinting Technology, Jorge Ivan Rodriguez

Open Access Theses & Dissertations

In the pharmaceutical industry, new chemicals and substances are being tested to find appropriate compounds or mix for treating a specific disease. The demand for screening large compound collections against and increasing number of therapeutic targets has stimulated technology development in the areas of assay automation and miniaturization. Current methods for evaluating the reactions of cells use a volume in the range of microliters. We have developed a new and low-cost deposition method to fabricate miniature drug screening platform that can realistically and inexpensively evaluate biochemical reactions up to 4 substances per trial in a picoliter-scale volume. This paper describes …

Computer Aided Drug Design Methods & Quantitative Structure-Activity/Property Relationships, Suman Sirimulla

Open Access Theses & Dissertations

The first part of dissertation consists of development of a QSAR model for 229 mutagenic aromatic amines and a QSPR model of partial molar volumes of amino acids. A common procedure for QSAR analysis consist of data selection (generally sets of homologous series of compounds and their corresponding biological activities), tabulation of trial physicochemical or molecular structural descriptors, followed by a multilinear statistical analysis to derive a statistically valid QSAR correlation of the activity data making use of a subset of the trial descriptors. A final important step is cross-validation to assess the putative predictive (rather than just correlative) capabilities …

Effects Of The Loss Of Multidrug Resistance Associated Protein 1 On Steroid Homeostasis, Dendritic Cell Function And Compensatory Mechanisms, Jeffrey Charles Sivils

Open Access Theses & Dissertations

The ATP-binding cassette (ABC) superfamily of membrane transporters use energy derived from ATP to eliminate a variety of exogenous and endogenous compounds from cells including anti cancer and anti viral drugs, metals steroids, bilirubin, cAMP, cGMP, leukotrienes , prostaglandins. The multi drug resistance associated protein family (MRP/ABBC) has been acknowledged as a major player involved in multi drug resistance (MDR), in which cancers stop responding a wide array of structurally and functionally unrelated chemotherapy drugs. Cancer is the second leading cause of death in adults in the United States. Although there have been great strides made the treatment of cancers …

Rare's Implementation Strategies Of Environmental Conservation In Indonesia, Alvaro Arvizo

Open Access Theses & Dissertations

Like most developing nations, Indonesia is at a crucial stage in its modern political and economic history. Opposing forces are constantly at work, a government struggling to make Indonesia a modern nation and the economic demands of a growing population. This presents the country with a multitude of problems. One of several is that nature's resources are exploited for personal economic gain with no regard for the long-term effects. This is a major concern for environmental conservation and non-profit government organizations (NGOs) worldwide. The American NGO Rare is at the forefront of this issue. Its aim is to meet community …

Mestizaje: Piro Indian And Spanish Vecino In Socorro, Texas From 1744 To 1813, David Camarena

Open Access Theses & Dissertations

This research examined culture on what is now the U.S./Mexico border, among Piro Indians and Spanish citizens (vecinos) in the community of Socorro, Texas between 1744 and 1813. The purpose was to better understand the process of mestizaje as experienced by Piro Indians as they participate in larger hegemonic Spanish civil and ecclesiastical institutions. Using archival materials along with secondary sources, this thesis reconstructs the antecedents that ultimately led the primary Indian community to transform into a Hispano settlement along the banks of the Río Grande. Pressured by vecino encroachment, participation in the Spanish wage-labor system, several environmental catastrophes in …

The Composition Of Precipitation In El Paso, Texas, Sonny P. Emmert

Open Access Theses & Dissertations

The composition of precipitation reflects the transport of particles from varying air mass source regions as well as input from local environmental and anthropogenic activities. Air research in El Paso, TX, U.S.A/Ciudad Juarez, Chihuahua, Mexico has been traditionally limited to studies of local inputs of air pollution; no transition has been made to studying the scavenging, washout, and transport of pollutants by precipitation. The goal of this research project was to identify transported pollutants in precipitation, and determine if there were any health and ecological implications. The research investigated biological, chemical, and geological constituents in precipitation samples collected between September …

Quality Assesment In Bone Scaffolds Through Internet Based Robotic Using Intelligent Data Mining, Aditya Chilukuri

Open Access Theses & Dissertations

Optimization of design in fabricating scaffolds in an important step in obtaining tissue engineering scaffolds with appropriate shape and inner microstructure. Different shapes & sizes of scaffolds are modeled using UGS NX 6.0 modeling software with variable pore sizes. The quality issue we are concerned is about scaffold porosity, because of fabrication errors the porosity is not be very high for few models. There is lot of research ongoing for characterization using scanning electron microscope, but this study will introduce a new technique to characterize the scaffolds using network based robots, machine vision system and conveyor facility using which the …

Pwisegen: A Genetic Algorithms-Based Framework For Pairwise Test Set Generation, Pedro Flores

Open Access Theses & Dissertations

Pairwise testing is a combinatorial testing approach that can be used to reduce the number of test cases dramatically for a software system. It specializes in the type of testing where the outcome of a system depends on the combination of several input parameters. This technique is widely used when there is not enough time to try out all possible combinations of the input parameters involved, because that would be very time consuming. The purpose of pairwise testing technique is to avoid testing all possible value combinations that a system can receive, and to preferably take a representative sample of …

Border Physician: The Life Of Lawrence A. Nixon, 1883-1966, Will Guzmán

Open Access Theses & Dissertations

This dissertation centers on the life of Dr. Lawrence Aaron Nixon, an African American physician and civil rights activist who lived in El Paso, Texas from 1910 until his death in 1966. Born in Marshall, Texas in 1883, Lawrence Nixon graduated from Wiley College in 1902 and Meharry Medical College in 1906. He then established a medical office in Cameron, Texas in 1907, but due to the racial climate and violence of central Texas he moved west to El Paso in hopes of a better life.

Although several historians have mentioned Dr. Nixon in their works, they have tended to …

Protean Storytellers: Journalists' Identities In An Uncertain Future, Lourdes Miriam Cueva Chacón

Open Access Theses & Dissertations

Journalism is undergoing a crisis period and, even though publishers, journalists and scholars do not agree about the future of news media industries, certainly they agree that what was once the dominant model of journalism is now changing drastically. Journalists are facing dynamic and changing environments that demand from them to develop new skills and to perform new roles. This is the environment where the new generation of journalists is forming, forcing them to rethink their future careers. For this research students' narratives where collected to determine the rhetorical ways in which students articulate their identity as journalists, what were …

Hydrological Characteristics Of A Large-Scale Flooding And Draining Experiment, Barrow, Alaska, Edith Jaurrieta De Velasco

Open Access Theses & Dissertations

The Arctic appears to be affected by climate change more so than any other region on Earth. Some of the most significant climate change impacts reported for the Arctic are associated with dramatic shifts in the hydrologic regime of terrestrial ecosystems. Understanding the hydrologic processes that are associated with different components of arctic terrestrial ecosystems is important because water in the form of snow or rain influences a range of properties and processes such as land-atmosphere energy and trace gas fluxes, nutrient cycling, ecosystem dynamics, biodiversity, periglacial processes and surface albedo. Furthermore, plants, animals, and native people of the Arctic …

Development Of A Micro-Catbed For Miniature Thrusters, Chance Paul Garcia

Open Access Theses & Dissertations

The goal of this work is to develop a micro catalytic bed for miniature thrusters. A test bed was constructed for experimental testing to characterize several parts of the micro catalytic bed. The reactant fluid studied is 90% Hydrogen Peroxide (H2O2) by weight. Three different cross sectional area designs were tested to determine decomposition efficiency, temperature reaction propensity, optimum flow rate, and temperature distribution across each bed. The products of decomposition were condensed to measure the oxygen released from decomposition. The results will be used to develop the basis for a micro catalytic bed design to implement into future miniature …

Computer-Aided Detection Of Sleep Apnea And Sleep Stage Classification Using Hrv And Eeg Signals, Edson F. Estrada

Open Access Theses & Dissertations

Sleep is a circadian rhythm essential for human life. Many events occur in the body during this state. In the past, significant efforts have been made to provide clinicians with reliable and less intrusive tools to automatically classify the sleep stages and detect apnea events. A few systems are available in the market to accomplish this task. However, sleep specialists may not have full confidence and trust in such systems due to issues related to their accuracy, sensitivity and specificity. The main objective of this work is to explore possible relationships among sleep stages and apneic events and improve on …

Cracked Spaces And Body Acts, Maria Miranda Maloney

Open Access Theses & Dissertations

Poetry of resistance, political, dealing with topics of identity, geography, forms and language.

Copper Isotope Fractionation During Surface Adsorption And Intracellular Incorporation By Bacteria, Jesica Urbina Navarrete

Open Access Theses & Dissertations

Copper isotopes may prove to be a useful tool for investigating bacteria-metal interactions recorded in natural waters, soils, and rocks. However, experimental data that constrain Cu isotope fractionation in biologic systems are limited and unclear. In this study we utilized Cu isotopes (65Cu) as a tool to investigate Cu-bacteria interactions, including surface adsorption and intracellular incorporation. Experiments were conducted with individual Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacterial species as well as with bacterial consortia from several natural environments. Adsorption experiments were conducted with live or dead cells over the pH range 2.5 to 6. Surface adsorption of Cu …

Making Africans And Indians: Colonialism, Identity, Racialization, And The Rise Of The Nation-State In The Florida Borderlands, 1765-1837, John Paul A. Nuño

Open Access Theses & Dissertations

The Florida Borderlands from 1765 to 1837 was a fluid space in which established colonial and Indigenous social, political, and economic systems were in dialogue with emerging discourses associated with the market economy, nationalism, and race. Utilizing British, Spanish, and United States government documents, diplomatic correspondence, and slave claims, this work traces the racialization of diverse Indigenous and African populations. Older colonial powers and nascent nation states sought to create political and social space between individuals within these categories in an effort to better control their labor, movement, and economic status. Consequently, Seminoles and Africans resisted and adapted, depending on …

Study Of Pbdes In Wastewater, Water And Sludge Of El Paso Del Norte Border Region Using Sbse Td/Gc-Ms, Beatriz Adriana Rocha-Gutierrez

Open Access Theses & Dissertations

Polybrominated diphenyl ethers (PBDEs) are a group of brominated compounds widely used as flame retardants. PBDEs are structurally similar to polychlorinated biphenyls (PCBs), and appear to act similarly in the environment. Due to their persistence and lipophilicity, PBDEs are found to be bioaccumulated and biomagnified in the food chain. Current research in PBDEs is focused on their occurrences, concentration, fate and transport in the environment, and the impact in the ecosystem and human health. Since PBDEs are not regulated in the USA, large amounts of these harmful chemicals are being dumped indiscriminately into the drainage system. As a result, these …