Digital Commons Network^™

Unraveling The Mechanism Of Selective Ion Transport In Hydrophobic Subnanometer Channels, Hui Li, Joseph S. Francisco, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Recently reported synthetic organic nanopore (SONP) can mimic a key feature of natural ion channels, i.e., selective ion transport. However, the physical mechanism underlying the K⁺/Na⁺ selectivity for the SONPs is dramatically different from that of natural ion channels. To achieve a better understanding of the selective ion transport in hydrophobic subnanometer channels in general and SONPs in particular, we perform a series of ab initio molecular dynamics simulations to investigate the diffusivity of aqua Na⁺ and K⁺ ions in two prototype hydrophobic nanochannels: (i) an SONP with radius of 3.2 Å, and (ii) single-walled …

Trans-Amazon Drilling Project (Tadp): Origins And Evolution Of The Forests, Climate, And Hydrology Of The South American Tropics, P. A. Baker, S. C. Fritz, C. G. Silva, C. A. Rigsby, M. L. Absy, R. P. Almeida, M. Caputo, C. M. Chiessi, F. W. Cruz, C. W. Dick, S. J. Feakins, J. Figueiredo, K. H. Freeman, C. Hoorn, C. Jaramillo, A. K. Kern, E. M. Latrubesse, M. P. Ledru, A. Marzoli, A. Myrbo, A. Noren, W. E. Piller, M. I. F. Ramos, C. C. Ribas, R. Trnadade, A. J. West, I. Wahnfried, D. A. Willard

Department of Earth and Atmospheric Sciences: Faculty Publications

This article presents the scientific rationale for an ambitious ICDP drilling project to continuously sample Late Cretaceous to modern sediment in four different sedimentary basins that transect the equatorial Amazon of Brazil, from the Andean foreland to the Atlantic Ocean. The goals of this project are to document the evolution of plant biodiversity in the Amazon forests and to relate biotic diversification to changes in the physical environment, including climate, tectonism, and the surface landscape. These goals require long sedimentary records from each of the major sedimentary basins across the heart of the Brazilian Amazon, which can only be obtained …

Nutrition-Related Policy And Environmental Strategies To Prevent Obesity In Rural Communities: A Systematic Review Of The Literature, 2002–2013, Larissa Calancie, Jennifer Leeman, Stephanie B. Jilcott Pitts, Laura Kettel Khan, Kelly R. Evenson, Michelle Schreiner, Carmen Byker, Clint Owens, Jared Mcguirt, Ellen Barnidge, Wesley Dean, Donna Johnson, Jane Kolodinsky, Emily Piltch, Courtney Pinard, Emilee Quinn, Lauren Whetstone, Alice Ammerman, Sheila Fleischhacker

Department of Nutrition and Health Sciences: Faculty Publications

Residents of rural communities in the United States are at higher risk for obesity than their urban and suburban counterparts. Policy and environmental-change strategies supporting healthier dietary intake can prevent obesity and promote health equity. Evidence in support of these strategies is based largely on urban and suburban studies; little is known about use of these strategies in rural communities. The purpose of this review was to synthesize available evidence on the adaptation, implementation, and effectiveness of policy and environmental obesity-prevention strategies in rural settings.

Reductions In Urinary Collection Frequency For Assessment Of Reproductive Hormones Provide Physiologically Representative Exposure And Mean Concentrations When Compared With Daily Collection, Heather C.M. Allaway, Nancy J. Williams, Rebecca J. Mallinson, Karsten Koehler, Mary Jane De Souza

Department of Nutrition and Health Sciences: Faculty Publications

Objective — To determine if reducing the frequency of urinary sample collection from daily to 5, 3, or 2 days per week during a menstrual cycle or 28-day amenorrheic monitoring period provide accurate representations of the reproductive hormone metabolites estrone- 1-glucuronide (E1G) and pregnanediol glucuronide (PdG) exposure and mean concentrations.

Methods — Exercising women presenting with eumenorrhea or exercise-associated menstrual disturbances collected daily urine samples for the assessment of E1G and PdG concentrations. After enzyme immunoassay analysis of the daily samples, E1G and PdG data were systematically removed from each menstrual cycle or amenorrheic monitoring period to mimic three reduced …

Cloning And Expression Of Ebi3 And P28 Subunits Of Human Interleukin 27 In E. Coli, Ameneh Koochaki, Mojgan Bandehpour, Sam Massahi, Mahrou Sadri, Bahram Kazemi

Department of Nutrition and Health Sciences: Faculty Publications

Background: Interleukin (IL)-27 is a heterodimeric cytokine belonging to IL-12 and IL-23 families, secreted by antigen presenting cells(APCs). The IL-27 is composed of 2 subunits: Epstein-Barr virus induced gene 3 (EBI3) and p28. IL-27 is an anti-inflammatory cytokine which has an inhibitory effect on Th17 population and suppress the IL-17 expression. It is suggested that IL-27 could be a potent drug candidate for treating auto immune diseases.

Materials and Methods: The EBI3 and p28 subunits of human interleukin 27 were constructed into plasmid vectors; they sub-cloned into pETDuet-1 expression vector in restriction sites of BamHI, SacI and NotI. Subsequently the …

Perceived Differences In Knowledge About Interactive Technology Between Young Adults And Their Parents, J. Mitchell Vaterlaus, Randall M. Jones, Sarah Tulane

Human Development and Family Studies Faculty Publications

This study was designed to investigate generational differences in knowledge about interactive technology (i.e., cell phones, social networking, email, video chat) between parents and their young adult children. Parents (n = 555) and young adults (n = 604) residing in the United States provided information about their knowledge in the use of interactive technology. Young adult children also reported their perceptions of their parents’ technological knowledge for the various technologies. Comparisons of young adult self-reported technological knowledge and their parents’ own reports of technological knowledge revealed that young adults were perceived to be much more knowledgeable than their parents (by …

Staphylococcus Aureus Metabolic Adaptations During The Transition From A Daptomycin Susceptibility Phenotype To A Daptomycin Nonsusceptibility Phenotype, Rosmarie Gaupp, Shulei Lei, Joseph M. Reed, Henrik Peisker, Susan Boyle- Vavra, Arnold S. Bayer, Markus Bischoff, Mathias Herrmann, Robert S. Daum, R. D. Powell, Greg A. Somerville

Robert Powers Publications

Staphylococcus aureus is a major cause of nosocomial and community-acquired infections. The success of S. aureus as a pathogen is due in part to its many virulence determinants and resistance to antimicrobials. In particular, methicillin-resistant S. aureus has emerged as a major cause of infections and led to increased use of the antibiotics vancomycin and daptomycin, which has increased the isolation of vancomycin-intermediate S. aureus and daptomycin-nonsusceptible S. aureus strains. The most common mechanism by which S. aureus acquires intermediate resistance to antibiotics is by adapting its physiology and metabolism to permit growth in the presence of these antibiotics, a …

Combining Di-Esi–Ms And Nmr Datasets For Metabolic Profiling, Darrell D. Marshall, Shulei Lei, Bradley Worley, Yuting Huang, Aracely Garcia- Garcia, Rodrigo Franco, Eric D. Dodds, Robert Powers

Robert Powers Publications

Metabolomics datasets are commonly acquired by either mass spectrometry (MS) or nuclear magnetic resonance spectroscopy (NMR), despite their fundamental complementarity. In fact, combining MS and NMR datasets greatly improves the coverage of the metabolome and enhances the accuracy of metabolite identification, providing a detailed and high-throughput analysis of metabolic changes due to disease, drug treatment, or a variety of other environmental stimuli. Ideally, a single metabolomics sample would be simultaneously used for both MS and NMR analyses, minimizing the potential for variability between the two datasets. This necessitates the optimization of sample preparation, data collection and data handling protocols to …

Deterministic Multidimensional Nonuniform Gap Sampling, Bradley Worley, Robert Powers

Robert Powers Publications

Born from empirical observations in nonuniformly sampled multidimensional NMR data relating to gaps between sampled points, the Poisson-gap sampling method has enjoyed widespread use in biomolecular NMR. While the majority of nonuniform sampling schemes are fully randomly drawn from probability densities that vary over a Nyquist grid, the Poisson-gap scheme employs constrained random deviates to minimize the gaps between sampled grid points. We describe a deterministic gap sampling method, based on the average behavior of Poisson-gap sampling, which performs comparably to its random counterpart with the additional benefit of completely deterministic behavior. We also introduce a general algorithm for multidimensional …

Volume 33 - Full Volume, Nfa Journal

National Forensic Journal

No abstract provided.

A Little Help From My Friends: A Relational Health Communication Competence Approach To Social Support For Forensic Educators, Heather J. Carmack, Todd T. Holm

National Forensic Journal

The purpose of this study was to examine factors that impact forensic educators’ perceived social support, including communication competence, job stress, and job burnout. Communicatively competent educators reported higher levels of administrative and family support than forensic educators who did not report high levels of communication competence. Educators who reported high levels of stress and burnout report lower levels of support from supervisors, coworkers, and family compared to educators who reported low levels of stress and burnout. Female coaches reported lower levels of support from supervisors, coworkers, and families, compared to male coaches. Educators with a large coaching staff reported …

Neural Circuit Dependence Of Acute And Subacute Nociception In C. Elegans, Yifan Xu

Student Theses and Dissertations

Nociception, the detection and avoidance of harmful cues, is a crucial system in all organisms. Animals use nociceptive systems to escape from substances that decrease survival, and can also modulate the threshold for avoidance behaviors to weigh the attractive features of an environment against its harmful features. To allow regulation, the nociception system of mammals incorporates multiple feedback and feedforward loops in its central and peripheral pathways. The nociception system of the roundworm Caenorhabditis elegans shares many features of the mammalian circuit. Both neural circuits feature a direct path from sensory neurons to motor neurons that is connected by a …

Development Of Novel Chemical Biology Tools For Probing Structure-Function Relationships In G Protein-Coupled Receptors, Tian He

Student Theses and Dissertations

G protein-coupled receptors (GPCRs) constitute a large family of transmembrane receptors that transduce extracellular signals into intracellular biochemical responses. Understanding with chemical precision how GPCRs function in cellular membranes is an active area of biological research, but despite recent reports of X-ray crystal structures of several GPCRs, some important questions remain unresolved. For example, the kinetics and thermodynamics of ligand-receptor interactions that lead to receptor activation and how allosteric modulators affect receptor signaling need to be addressed. In addition to basic understanding of transmembrane signaling, studies of GPCRs can provide insights that might advance drug discovery since a large proportion …

A Reductionist Approach To Modeling Human Corticogenesis, Mohammad Zeeshan Ozair

Student Theses and Dissertations

The formation of the mammalian cerebral cortex is a complex multi‐tiered process that involves three major milestones: 1) neural induction and folding of the neuroepithelium, 2) areal patterning and generation of various progenitor types, and 3) corticogenesis. Our current understanding of the molecular and cellular basis of cortical development comes largely from mouse studies due to the genetic tractability of this model system. However, as primate studies have shown, the primate brain is unique in terms of its progenitor and neuronal composition, cortical areas, scale, and gene expression. Limitations in the availability of non‐human primate and human fetal material, the …

Metagenomics-Based Tryptophan Dimer Natural Product Discovery And Development Pipeline, Fang-Yuan Chang

Student Theses and Dissertations

Most microbial natural product discovery programs rely on the growth of bacteria in the laboratory, yet it is now well established that the vast majority of bacteria in the environment have not been cultured, particularly from the diverse soil microbiota. By extracting DNA directly from soil samples to construct large archived environmental DNA (eDNA) libraries, thousands of genomes from both cultured and as yet uncultured bacteria can be simultaneously screened for gene clusters encoding natural products of interest. Several natural products with pharmaceutically relevant biological activity arise from the dimerization of tryptophans, such as staurosporine, rebeccamycin, and violacein. To discover …

Effects Of Temporal And Spatial Context Within The Macaque Face-Processing System, Clark Andrew Fisher

Student Theses and Dissertations

Temporal and spatial context play a key role in vision as a whole, and in face perception specifically. However, little is known about the neurophysiological mechanisms by which contextual cues exert their effects. Anatomically distinct face patches in the macaque brain analyze facial form, and studies of the activity within these patches have begun to clarify the neural machinery that underlies facial perception. This system provides a uniquely valuable opportunity to study how context affects the perception of form. We used functional magnetic resonance imaging (fMRI) to investigate the brain activity of macaque monkeys while they viewed faces placed in …

Hair Bundles Of A Jawless Vertebrate Employ Tetrapod-Like Tuned Mechanical Amplification, Katherine J. Leitch

Student Theses and Dissertations

In the hearing and balance organs of tetrapod vertebrates, mechanical signals are transduced by an elegant organelle called the hair bundle. Deflections of this structure apply forces to mechanically gated ion channels. Hair bundles are not passive receivers of stimuli, but are instead active participants in the process of sensory transduction. They expend chemical energy to exert mechanical work, and can harness this active process to amplify their mechanical response to stimuli. Furthermore, the active process is tuned, allowing a given hair bundle to preferentially amplify a particular frequency; this feature is valuable in the analysis of complex sounds. Hair …

A Mechanism For Spatial Orientation Based On Sensory Adaptation In Caenorhabditis Elegans, Johannes Larsch

Student Theses and Dissertations

During chemotaxis, animals compute spatial information about odor gradients to make navigational choices for finding or avoiding an odor source. The challenge to the neural circuitry is to interpret and respond to odor concentrations that change over time as animals traverse a gradient. In this thesis, I ask how a nervous system regulates spatial navigation by studying the chemotaxis response of Caenorhabditis elegans to diacetyl. A behavioral analysis demonstrated that AWA sensory neurons drive chemotaxis over several orders of magnitude in odor concentration, providing an entry point for dissecting the mechanistic basis of chemotaxis at the level of neural activity. …

Studies On The Maturation Of Secreted Quorum Sensing Peptides That Regulates S. Aureus Virulence, Jeffrey Grant Johnson

Student Theses and Dissertations

The accessory gene regulator (agr) locus in the commensal human pathogen, Staphylococcus aureus, is a two-promoter operon with allelic variability that encodes a quorum sensing circuit involved in regulating virulence in the bacterium. Secretion of unique autoinducing peptides (AIPs) and detection of their concentration via AgrC, a transmembrane receptor histidine kinase, coordinates local bacterial population density with global changes in gene expression. In order for S. aureus to produce AIP, three proteolytic transformations involving the proteins AgrB and SpsB are required. However, despite our current understanding of AIP peptide processing, the actual manner in which the AIP crosses the cellular …

Why Mosquitoes Bite Some People More Than Others: Metabolic Correlates Of Human Attraction In Aedes Aegypti, Lindsay Lee Bellani

Student Theses and Dissertations

Aedes aegypti mosquitoes are the principal vectors of two major infectious diseases that plague the developing world today: dengue fever and chikungunya, with dengue fever alone resulting in ~400 million total yearly infections, and ~24,000 deaths (Bhatt et al., 2013). Understanding the biology behind Ae. aegypti attraction to humans is critical for developing novel strategies to combat these diseases. Yet, even the basic act of how mosquitoes choose one human host over another is poorly understood. Many previous studies on differential attraction have focused on small, homogenous subject populations and addressed a single hypothesis. We took the opposite strategy and …

Molecular Determinants Of Tumor Re-Initiation In Breast Cancer, Jason Barzel Ross

Student Theses and Dissertations

Cancer progression is characterized by the formation of tumors in primary organs and the subsequent re-formation of tumors in distant metastatic sites. The tumorigenic, or tumor-forming, capacity of cancer cells drives cancer along a continuum that includes primary tumor formation, metastatic re-initiation, and macroscopic relapse. As such, a greater understanding of the biological features and molecular determinants that govern tumor-forming capacity in the primary and metastatic site is of great importance to the scientific and biomedical communities. This thesis presents an unbiased approach to systematically select and characterize breast cancer cells with enhanced tumorigenic capacity in order to elucidate genes …

Identification Of Tmem2 As A Sox4 Transcriptional Target Involved In Breast Cancer Metastasis, Hyeseung Lee

Student Theses and Dissertations

The transcription factor SRY (sex determining region Y)-box 4 (SOX4) regulates embryonic development and has been shown to drive the progression and metastasis of multiple solid cancer types. A common transcriptional target of SOX4 that mediates its effects in multiple cancer types has yet to be identified. Through a systematic molecular and genomic approach, we identify the transmembrane protein 2 (TMEM2) gene as a direct transcriptional target of SOX4. TMEM2 is transcriptionally activated by SOX4 in both breast cancer and lung adenocarcinoma cells and mediates pro-invasive and pro-migratory effects of SOX4. TMEM2, like SOX4, is sufficient to promote breast cancer …

Components Of The Ubiquitin Proteasome System Are Required For The Nonapoptotic Death Of The C. Elegans Linker Cell, Jennifer Zuckerman Malin

Student Theses and Dissertations

Cell death is a major cell fate that promotes tissue sculpting and morphogenesis during animal development. Many developmental cell-culling events cannot be accounted for solely by caspase-dependent apoptosis, yet, alternate pathways are poorly understood. Direct evidence that caspase-independent non-apoptotic cell death pathways operate during animal development is provided by studies of the C. elegans linker cell. Genetic studies of linker cell death have led to the identification of genes that promote this process, including pqn-41, which encodes a glutamine-rich protein, as well as tir-1/TIRdomain and sek-1/MAPKK, which may function in the same pathway as pqn-41. The let- 7 microRNA and …

Activity Based Profiling: New Insights Into Metabolic Homeostasis, Keith Tan

Student Theses and Dissertations

There is mounting evidence that demonstrates that body weight and energy homeostasis is tightly regulated by a physiological system. This system consists of sensing and effector components that primarily reside in the central nervous system and disruption to these components can lead to obesity and metabolic disorders. Although many neural substrates have been identified in the past decades, there is reason to believe that there are numerous unidentified neural populations that play a role in energy balance. Besides regulating caloric consumption and energy expenditure, neural components that control energy homeostasis are also tightly intertwined with circadian rhythmicity but this aspect …

The Effect Of Chronic Hypertension On Neuropathology In The Tgswdi Mouse Model Of Alzheimer's Disease, Anna Kruyer

Student Theses and Dissertations

Numerous epidemiological studies link vascular disorders, such as hypertension, diabetes and stroke, with Alzheimer's disease. Hypertension, specifically, is an important modifiable risk factor for late onset Alzheimer's disease. Despite the abundance of clinical data connecting these conditions, animal studies investigating the connection between the two are lacking. To examine the link between midlife hypertension and the onset of Alzheimer's disease later in life, chronic hypertension was induced in the TgSwDI mouse model of Alzheimer's disease in early adulthood using long-term administration of the eNOS inhibitor, Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME). L-NAME treatment accelerated cognitive deficits, microvascular deposition of the amyloidbeta …

A New Role For Beta-Amyloid In Alzheimer's Disease: Initiation Of Thrombotic And Inflammatory Processes Via Coagulation Factor Xii And Fibrinogen, Daria Zamolodchikov

Student Theses and Dissertations

Alzheimer's disease (AD) is a progressive neurodegenerative disorder with no effective therapies. While abundant genetic, histological, and experimental evidence links the beta-amyloid (Aβ) peptide to disease onset and progression, the mechanisms behind neuronal dysfunction in AD are not completely understood. It is now clear that AD is a complex, multifactorial disease characterized by vascular dysfunction, prothrombotic state, and inflammation, but whether these conditions are a cause or consequence of disease is debated. Prothrombotic and inflammatory states can contribute to alterations in cerebral blood flow resulting in hypoperfusion. Since neuronal function is dependent on an uninterrupted blood supply sustained by a …

A Genomic Portrait Of Hepatitis C Virus And Microrna-122, Joseph M. Luna

Student Theses and Dissertations

Hepatitis C virus (HCV) uniquely requires the liver specific microRNA-122 (miR-122) for replication, yet global effects on endogenous microRNA (miRNA) targets during infection are unexplored. In this body of work, we employed highthroughput sequencing and crosslinking immunoprecipitation (HITS-CLIP) experiments of human Argonaute (AGO) during HCV infection. We demonstrate robust AGO binding on the 5' untranslated region of HCV RNA at known and predicted miR-122 sites, thereby establishing conclusive biochemical evidence of endogenous miR-122 action on HCV RNA that firmly agrees with previous genetic evidence. We further characterize novel AGO binding on HCV RNA to determine its dependence on miR-122, miRNAs …

Mechanical Control Of Sensory Hair-Bundle Function, Joshua D. Salvi

Student Theses and Dissertations

Hair bundles detect sound in the auditory system, head position and rotation in the vestibular system, and fluid flow in the lateral-line system. To do so, bundles respond to periodic, static, and hydrodynamic forces contingent upon the receptor organs in which they are situated. As the mechanosensory function of a hair bundle varies, so too do the mechanical properties of the bundle and its microenvironment. Hair bundles range in height from 1 μm to 100 μm and in stiffness from 100 μN/m to 10,000 μN/m. They are composed of actin-filled, hypertrophic microvilli—stereocilia—that number from fewer than 20 through more than …

Functional Dissection Of Brainstem Circuitry, Alexander Ryan Nectow

Student Theses and Dissertations

Eat. Sleep. Breathe. Move. These functions, critical to an individual's survival, are controlled by highly conserved neurotransmitter and neuromodulatory systems, which are principally located in the brainstem. These different brainstem neural populations, while performing apparently simple life sustaining functions, are remarkably complex. For proper function, survival circuits need to receive information from brain regions responsible for sensing survival needs, and rapidly exert broad control over the brain to generate adaptive behavior like foraging during energy deficit and escape from predation. How can survival circuits generate such autocratic control? Survival circuits principally affect global brain function in two ways: diffuse projection …

Proud To Be Autistic: Metaphorical Construction And Salience Of Cultural And Personal Identity In #Stopcombatingme, Jessica Benham

All Graduate Theses, Dissertations, and Other Capstone Projects

Like many other autistic individuals, I struggle to find language to appropriately describe my experiences. Furthermore, within the Autistic community, debates over appropriate language use are frequent, including discussions on person-first language versus identity-first language, functioning language, and medical terminology. Through this research, I examine how rhetorical constructions of Autism gain power, focused on the role of language choice with regard to personal identity and self-advocacy and conduct a discourse analysis of the #StopCombatingMe movement on Twitter. Spearheaded by ASAN, a grassroots organization which seeks to challenge public dialogue on Autism, #StopCombatingMe sought to argue against the reauthorization of the …