Digital Commons Network^™

Identification Of Synthetic Chemical Compound Inhibitors Of Pseudomonas Aeruginosa Protein Synthesis And The Development Of Lead Series, Stephanie O. Palmer

Theses and Dissertations

Pseudomonas aeruginosa is a ubiquitous Gram-negative bacteria and a primary cause of nosocomial infections. An aminoacylation/translation (A/T) assay was developed using P. aeruginosa components to perform poly(U) mRNA directed protein synthesis. Using scintillation proximity assay (SPA) technology a high-throughput screening (HTS) platform was developed. A synthetic chemical compound library (>900) was screened, 36 hit compounds were identified and molecular targets were determined. Compounds were analyzed for enzymatic inhibition (IC50) and inhibition of bacterial cultures (MIC). Time-kill studies determined bacterial growth to be bacteriostatic or bactericidal in the presence of inhibitor. Mechanism of action, effects on eukaryotic cytosolic and mitochondrial …

Molecular Dynamic Simulation Studies Of The Androgen Receptor Complexed With 5Α-Dihydrotestosterone And An Allosteric Ligand, Everardo Villarreal Ii

Theses and Dissertations

Receptors are important drug targets for the pharmaceutical industry, since they are involved in many illnesses. Nuclear receptors are a subset of receptors that control a variety of physiological events, by expression of genes from DNA. One of the nuclear receptors, the androgen receptor, is a steroid binding receptor that controls a variety of regulatory and development functions in the body. It is also the cause of some types of cancer, so the inhibition of this receptor is crucial. One of the processes studied to inhibit the function of the receptor is to see if an allosteric ligand, TRIAC, can …

Analysis And Simulation Of A Social Network, Twitter: A Case Study, Jonatan Reyes

Theses and Dissertations

The use of online social networks empowers its users to efficiently disseminate information across traditional social networks. Typically, the weight and value of messages are relative to its readers’ culture and interests. Nevertheless, in some instances, messages take the form of viral phenomenon, which circulates around the world in very short periods of time. Therefore, despite the actual content of the message spread over the network, the determination of the effectiveness of message dissemination across the social network becomes an attractive opportunity for scientific study. Since a meticulous analysis of a complete online social network would require the acquisition of …

Hydrodesulfurization Of Dibenzothiophene Using Comos2, Jacob S. Sollner

Theses and Dissertations

The hydrodesulphurization (HDS) of crude oils is an important industrial process to remove sulfur from fuels. In this study, DBT was used as a model compound to study the removal of sulfur from a decahydronaphthalene solution. The catalyst was synthesized through low pressure pathways in the absence of H2S. All the synthesized catalyst were investigated using a combination of SEM, RAMAN spectroscopy, and XRD. The materials were studied for their ability to remove DBT from solution and the reaction products were analyzed. It was observed that the major reaction pathway was the direct desulphurization pathway and zero order reaction kinetics …

Potential And Timescales For Oxygen Depletion In Coastal Upwelling Systems: A Box-Model Analysis, Cheryl S. Harrison, B. Hales, S. Siedlecki, R. M. Samelson

School of Earth, Environmental, & Marine Sciences Faculty Publications

A simple box model is used to examine oxygen depletion in an idealized ocean-margin upwelling system. Near-bottom oxygen depletion is controlled by a competition between flushing with oxygenated offshore source waters and respiration of particulate organic matter produced near the surface and retained near the bottom. Upwelling-supplied nutrients are consumed in the surface box, and some surface particles sink to the bottom where they respire, consuming oxygen. Steady states characterize the potential for hypoxic near-bottom oxygen depletion; this potential is greatest for faster sinking rates, and largely independent of production timescales except in that faster production allows faster sinking. Timescales …

Adult Hispanic Students' Attitudes Toward Writing In English In A U.S. Bilingual Community, Analynn Bustamante

Theses and Dissertations

Attitude is widely regarded as a key component for writing achievement. This study explores the relationship between students’ language dominance and their attitudes toward writing in English. Seventy-seven Hispanic adult students were recruited to participate in a survey. Four writing domains were tested: writing in general, writing in STEM courses, writing in humanities courses and writing in electronic communication. Participants’ attitudes toward four different writing domains were compared. Significant difference was found between attitudes toward general writing attitudes and attitudes toward writing STEM courses, as well as between general writing and writing in humanities courses. Additionally, participants were divided by …

Comunicando Emociones: Language Preferences For Hispanics In The Rio Grande Valley, Elim Hernandez

Theses and Dissertations

According to the U.S Census Bureau, more than one million Hispanic or Latino individuals live in the southernmost area of Texas called The Rio Grande Valley (RGV). However, being Hispanic in the RGV does not mean you speak Spanish. In fact, most of the population speaks English and/or Spanish or “Spanglish” (Tex-Mex). As a result, individuals face code-switching (switching back and forth in two languages) when they communicate with one another. Which language do they prefer to express their emotions in? The study posed a research question along this line. Nine college students who met the research criteria were interviewed …

The Rider (2016-04-25), Jesus Sanchez

The Rider Archives

Vol.1 No.27

The Rider (2016-04-18), Jesus Sanchez

The Rider Archives

Vol.1 No.26

Removal Of Arsenic From Water Using Synthetic Fe7s8 Nanoparticles, Jesus Cantu, Louis E. Gonzalez, Jacqueline Goodship, Monica Contreras, Meera Joseph, Cameron Garza, Thomas Eubanks, Jason Parsons

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

In the present study, pyrrhotite was used to remove arsenite and arsenate from aqueous solutions. The Fe7S8 was synthesized using a solvothermal synthetic method and it was characterized using XRD and SEM micrographs. Furthermore, the particle size for the nanomaterial Fe7S8 was determined to be 29.86 ± 0.87 nm using Scherer’s equation. During the pH profile studies, the optimum pH for the binding of As (III) and As (V) was determined to be pH 4. Batch isotherm studies were performed to determine the binding capacity of As(III) and As(V), which was determined to be 14.3 mg/g and 31.3 mg/g respectively …

Harmonic Maps Surfaces And Relativistic Strings, Paul Bracken

School of Mathematical & Statistical Sciences Faculty Publications

The harmonic map is introduced and several physical applications are presented. The classical nonlinear σ model can be looked at as the embedding of a two-dimensional surface in a threedimensional sphere, which is itself embedded in a four-dimensional space. A system of nonlinear evolution equations are obtained by working out the zero curvature condition for the Gauss equations relevant to this geometric formulation.

New Discoveries From The Arecibo 327 Mhz Drift Pulsar Survey Radio Transient Search, J. S. Deneva, Kevin Stovall, M. A. Mclaughlin, M. Bagchi, S. D. Bates, P. C.C. Freire, Jose Guadalupe Martinez, Fredrick Jenet

Physics & Astronomy Faculty Publications

We present Clusterrank, a new algorithm for identifying dispersed astrophysical pulses. Such pulses are commonly detected from Galactic pulsars and rotating radio transients (RRATs), which are neutron stars with sporadic radio emission. More recently, isolated, highly dispersed pulses dubbed fast radio bursts (FRBs) have been identified as the potential signature of an extragalactic cataclysmic radio source distinct from pulsars and RRATs. Clusterrank helped us discover 14 pulsars and 8 RRATs in data from the Arecibo 327 MHz Drift Pulsar Survey (AO327). The new RRATs have DMs in the range 23.5-86.6 pc cm-3 and periods in the range 0.172-3.901 s. The …

The Nanograv Nine-Year Data Set: Limits On The Isotropic Stochastic Gravitational Wave Background, Z. Arzoumanian, A. Brazier, S. Burke-Spolaor, S. J. Chamberlin, S. Chatterjee, B. Christy, J. M. Cordes, N. J. Cornish, Fredrick A. Jenet, Jing Luo

Physics & Astronomy Faculty Publications

We compute upper limits on the nanohertz-frequency isotropic stochastic gravitational wave background (GWB) using the 9 year data set from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration. Well-tested Bayesian techniques are used to set upper limits on the dimensionless strain amplitude (at a frequency of 1 yr-1) for a GWB from supermassive black hole binaries of Agw < 1.5 × 10-15. We also parameterize the GWB spectrum with a broken power-law model by placing priors on the strain amplitude derived from simulations of Sesana and McWilliams et al. Using Bayesian model selection we find that the data favor a broken power law to a pure power law with odds ratios of 2.2 and 22 to one for the Sesana and McWilliams prior models, respectively. Using the broken power-law analysis we construct posterior distributions on environmental factors that drive the binary to the GW-driven regime including the stellar mass density for stellar-scattering, mass accretion rate for circumbinary disk interaction, and orbital eccentricity for eccentric binaries, marking the first time that the shape of the GWB spectrum has been used to make astrophysical inferences. Returning to a power-law model, we place stringent limits on the energy density of relic GWs, Ωgw(f)h2 < 4.2 × 10-10. Our limit on the cosmic string GWB, Ωgw(f)h2 < 2.2 × 10-10, translates to a conservative limit on the cosmic string tension with Gμ < 3.3 × 10-8, a factor of four better than the joint Planck and high-l cosmic microwave background data from other experiments.

Parametric Analysis Of A Solid Oxide Fuel Cell Auxiliary Power Unit Operating On Syngas Produced By Autothermal Reforming Of Hydrocarbon Fuels, Jun Dong, Xinhai Xu, Ben Xu, Shuyang Zhang

Mechanical Engineering Faculty Publications

A 1 kWe integrated auxiliary power unit (APU) system consisting of an autothermal reformer and a solid oxide fuel cell (SOFC) unit, as well as balance-of-plant components, was designed and analyzed. A relatively easy-to-approach SOFC model was developed in order to conveniently calculate V-I and P-I curves and the system's net efficiency at different operating conditions. The effects of steam to carbon and oxygen to carbon ratios in the reactants, channel dimensions of the SOFC unit, and hydrocarbon fuel types on the integrated APU system's performance were discussed. Five hydrocarbon fuels including diesel, Jet-A, gasoline, ethanol, and methanol were studied …

Utrgv Commencement – Spring 2016, The University Of Texas Rio Grande Valley

UTRGV Commencement Programs

No abstract provided.

Multicollinearity In Regression Analyses Conducted In Epidemiologic Studies, Kristina Vatcheva, Minjae Lee, Joseph B. Mccormick, Mohammad H. Rahbar

School of Mathematical & Statistical Sciences Faculty Publications

The adverse impact of ignoring multicollinearity on findings and data interpretation in regression analysis is very well documented in the statistical literature. The failure to identify and report multicollinearity could result in misleading interpretations of the results. A review of epidemiological literature in PubMed from January 2004 to December 2013, illustrated the need for a greater attention to identifying and minimizing the effect of multicollinearity in analysis of data from epidemiologic studies. We used simulated datasets and real life data from the Cameron County Hispanic Cohort to demonstrate the adverse effects of multicollinearity in the regression analysis and encourage researchers …

Ultraviolet Radiation-Induced Tumor Necrosis Factor Alpha, Which Is Linked To The Development Of Cutaneous Scc, Modulates Differential Epidermal Micrornas Expression, Ashok Singh, Estelle Willems, Anupama Singh, Bilal B. Hafeez, Irene M. Ong, Suresh L. Mehta, Ajit K. Verma

School of Medicine Publications

Chronic exposure to ultraviolet radiation (UVR) is linked to the development of cutaneous squamous cell carcinoma (SCC), a non-melanoma form of skin cancer that can metastasize. Tumor necrosis factor-alpha (TNFα), a pro-inflammatory cytokine, is linked to UVR-induced development of SCC. To find clues about the mechanisms by which TNFα may promote UVR-induced development of SCC, we investigated changes in the expression profiling of microRNAs (miRNA), a novel class of short noncoding RNAs, which affects translation and stability of mRNAs. In this experiment, TNFα knockout (TNFα KO) mice and their wild type (WT) littermates were exposed to acute UVR (2.0 kJ/m2) …

Gw150914: Implications For The Stochastic Gravitational-Wave Background From Binary Black Holes, B. P. Abbott, R. Abbott, Hernan P. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, Marc E. Normandin, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano

Physics & Astronomy Faculty Publications

The LIGO detection of the gravitational wave transient GW150914, from the inspiral and merger of two black holes with masses 30M, suggests a population of binary black holes with relatively high mass. This observation implies that the stochastic gravitational-wave background from binary black holes, created from the incoherent superposition of all the merging binaries in the Universe, could be higher than previously expected. Using the properties of GW150914, we estimate the energy density of such a background from binary black holes. In the most sensitive part of the Advanced LIGO and Advanced Virgo band for stochastic backgrounds (near 25 Hz), …

Gw150914: The Advanced Ligo Detectors In The Era Of First Discoveries, B. P. Abbott, R. Abbott, T. D. Abbott, M. R. Abernathy, F. Acernese, Hernan P. Daveloza, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov

Physics & Astronomy Faculty Publications

Following a major upgrade, the two advanced detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) held their first observation run between September 2015 and January 2016. With a strain sensitivity of 10-23/Hz at 100 Hz, the product of observable volume and measurement time exceeded that of all previous runs within the first 16 days of coincident observation. On September 14, 2015, the Advanced LIGO detectors observed a transient gravitational-wave signal determined to be the coalescence of two black holes [B. P. Abbott et al., Phys. Rev. Lett. 116, 061102 (2016)], launching the era of gravitational-wave astronomy. The event, GW150914, was …

Exploring Parent-Teacher Partnerships As Border Pedagogy: Supporting Emergent Bilingual Student Learning, Sandra Mercuri

Bilingual and Literacy Studies Faculty Publications

Developed by a bilingual teacher educator in the U.S. working with in-service teachers serving predominantly bilingual students from U.S. and Mexico, this study is uniquely positioned to use innovative research in bilingual teacher education for empowering teachers to develop culturally and linguistically responsive border pedagogies. Specifically, this study explores parent-teacher partnerships as border pedagogy that supports emergent bilingual student teaching and learning. Aimed at disrupting traditional modes of research and practice grounded in monolingualism, this qualitative critical study uses the concept of border pedagogy as a theoretical framework to explore how 16 bilingual in-service teachers enrolled in a master’s program …

Accessing The Exceptional Points Of Parity-Time Symmetric Acoustics, Chengzhi Shi, Marc Dubois, Yun Chen, Lei Cheng, Hamidreza Ramezani, Yuan Wang, Xiang Zhang

Physics & Astronomy Faculty Publications

Parity-time (PT) symmetric systems experience phase transition between PT exact and broken phases at exceptional point. These PT phase transitions contribute significantly to the design of single mode lasers, coherent perfect absorbers, isolators, and diodes. However, such exceptional points are extremely difficult to access in practice because of the dispersive behaviour of most loss and gain materials required in PT symmetric systems. Here we introduce a method to systematically tame these exceptional points and control PT phases. Our experimental demonstration hinges on an active acoustic element that realizes a complex-valued potential and simultaneously controls the multiple interference in the structure. …

The Rider (2016-03-28), Jesus Sanchez

The Rider Archives

Vol.1 No.24

Is Bad Stronger Than Good? The Impact Of Police-Citizen Encounters On Public Satisfaction With The Police, Yudu Li, Ling Ren, Fei Luo

Criminal Justice Faculty Publications

Purpose

Drawing upon the negativity bias theory, the purpose of this paper is to examine the effects of positive and negative perceptions of police-initiated or citizen-initiated contacts on three distinctive dimensions of public satisfaction with police (PSWP).

Design/methodology/approach

The data were obtained from a random-sample telephone survey of 1,143 residents in Houston in 2012. The OLS regressions were conducted with variables derived from the contact model and neighborhood context model that were often employed in the PSWP research. Particularly, five dichotomous variables were created to tap into the nature and quality of the police-citizen encounters.

Findings

The results confirm the …

A Six-Stage Framework For Evolutionary Is Research Using Path Models: Conceptual Development And A Social Networking Illustration, Ned Kock, Murad Moqbel

Information Systems Faculty Publications

Purpose

The purpose of this study is to fill a gap in evolutionary theorizing in the field of information systems. Evolutionary theorizing has recently been added as a useful tool to the research repertoire of information systems investigators. However, the literature on evolutionary theorizing and related empirical research lacks a clear framework that explicitly shows how information systems researchers can go, step-by-step, from a generic model of the evolution of traits in our ancestral past to a more specific model depicting the effects of technology facilitation of those traits among modern humans. The purpose of this study is to fill …

Pre- And In-Service Teachers’ Perceptions Of Learning Through Research Workshops In A Hispanic-Serving Institution In Usa: A Review Of Two Years’ Accumulative Data, Ming-Tsan P. Lu, Yousun Shin, Terry Overton

Teaching and Learning Faculty Publications

The purpose of the study was to report the analysis results of two-year accumulative data from Research Academy workshops held for pre-service and in-service teachers in a southern state Hispanic-Serving Institution. Graduate students’ perceptions of learning through these professional development workshops were reported. Statistical analyses were performed. The study found consistent and significant gains of participants’ confidence in educational research skills and knowledge. Future directions, limitations, and implications were discussed.

Carbon Abatement And Emissions Associated With The Gasification Of Walnut Shells For Bioenergy And Biochar Production, Engil Isadora Pujol Pereira, Emma C. Suddick, Johan Six

School of Earth, Environmental, & Marine Sciences Faculty Publications

By converting biomass residue to biochar, we could generate power cleanly and sequester carbon resulting in overall greenhouse gas emissions (GHG) savings when compared to typical fossil fuel usage and waste disposal. We estimated the carbon dioxide (CO2) abatements and emissions associated to the concurrent production of bioenergy and biochar through biomass gasification in an organic walnut farm and processing facility in California, USA. We accounted for (i) avoided-CO2 emissions from displaced grid electricity by bioenergy; (ii) CO2 emissions from farm machinery used for soil amendment of biochar; (iii) CO2 sequestered in the soil through stable biochar-C; and (iv) direct …

Cirrhosis And Advanced Fibrosis In Hispanics In Texas: The Dominant Contribution Of Central Obesity, Jingjing Jiao, Gordon P. Watt, Minjae Lee, Mohammad H. Rahbar, Kristina Vatcheva, Jen-Jung Pan, Joseph B. Mccormick, Susan P. Fisher-Hoch, Michael Fallon, Laura Beretta

School of Mathematical & Statistical Sciences Faculty Publications

Liver cirrhosis is a leading cause of death in Hispanics and Hispanics who live in South Texas have the highest incidence of liver cancer in the United States. We aimed at determining the prevalence and associated risk factors of cirrhosis in this population. Clinical and demographic variables were extracted for 2466 participants in the community-based Cameron County Hispanic Cohort in South Texas. Aspartate transaminase to Platelet Ratio Index (APRI) was used to predict cirrhosis in Cameron County Hispanic Cohort. The prevalence of cirrhosis using APRI≥2 was 0.94%, which is nearly 4-fold higher than the national prevalence. Using APRI≥1, the overall …

Forcespinning: A New Method For The Mass Production Of Sn/C Composite Nanofiber Anodes For Lithium Ion Batteries, Victor Agubra, Luis Zuniga, David De La Garza, Luis Gallegos, Madhab Pokhrel, Mataz Alcoutlabi

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

The development of nanostructured anode materials for rechargeable Lithium-ion Batteries has seen a growing interest. We herein report the use of a new scalable technique, Forcespinning (FS) to produce binder-free porous Sn/C composite nanofibers with different Sn particle size loading. The preparation process involves the FS of Sn/PAN precursor nanofibers and subsequently stabilizing in air at 280 °C followed by carbonization at 800 °C under an inert atmosphere. The Sn/C composite nanofibers are highly flexible and were directly used as binder-free anodes for lithium-ion batteries. The produced Sn/C composite nanofibers showed an improved discharge capacity of about 724 mA …

Liver And Other Gastrointestinal Cancers Are Frequent In Mexican Americans, Ariana L. Garza, Kristina Vatcheva, Jen-Jung Pan, Mohammad H. Rahbar, Michael Fallon, Joseph B. Mccormick, Susan P. Fisher-Hoch

School of Mathematical & Statistical Sciences Faculty Publications

Background

Disease patterns in Mexican-American health-disparity populations differ from larger United States populations.

Aims

Determine frequency of gastrointestinal cancers in Mexican Americans.

Methods

We analyzed self-reported data from the Cameron County Hispanic Cohort where we find high rates of risk factors for cancer: obesity (48.5%), diabetes (30.7%). Participants provided cancer histories about themselves and first and second degree relatives. Logistic regression models assessed risk factors. Frequencies of cancer sites were ranked and validated using concurrent age local cancer registry data.

Results

Among 9,249 individuals (participants and their relatives) there were 1,184 individuals with reports of cancer. Among cohort participants under …

1h, 13c And 15n Resonance Assignments And Secondary Structure Analysis Of Translation Initiation Factor 1 From Pseudomonas Aeruginosa, Alejandra Bernal, Yanmei Hu, Stephanie O. Palmer, Aaron Silva, James M. Bullard, Yonghong Zhang

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen and a primary cause of infection in humans. P. aeruginosa can acquire resistance against multiple groups of antimicrobial agents, including β-lactams, aminoglycosides and fluoroquinolones, and multidrug resistance is increasing in this organism which makes treatment of the infections difficult and expensive. This has led to the unmet need for discovery of new compounds distinctly different from present antimicrobials. Protein synthesis is an essential metabolic process and a validated target for the development of new antibiotics. Translation initiation factor 1 from P. aeruginosa (Pa-IF1) is the smallest of the three initiation factors that acts …