Digital Commons Network^™

Experimental Testing And Finite-Element Modeling To Evaluate The Effects Of Aggregate Angularity On Bituminous Mixture Performance, Leonardo T. Souza, Yong-Rak Kim, Flavio V. Souza, Leandro S. Castro

Department of Engineering Mechanics: Faculty Publications

This study evaluates the effects of aggregate angularity in bituminous mixtures. Previous studies have predominantly focused on the effects of aggregate angularity on the resistance to permanent deformation, while little work has investigated the role of aggregate angularity related to mixture volumetrics and fatigue fracture performance. To investigate the effect of aggregate angularity on mixture performance and characteristics, five mixes with different combinations of coarse and fine aggregate angularity are evaluated by performing the uniaxial static creep test and the indirect tensile fracture energy test. The asphalt pavement analyzer test is also performed with five-year field project mixtures. Fracture energy …

A Low-Cost, Reliable, High-Throughput System For Rodent Behavioral Phenotyping In A Home Cage Environment, Steven A. Parkison, Jay D. Carlson, Tammy R. Chaudoin, Traci A. Hoke, A. Katrin Schenk, Evan H. Goulding, Lance C. Pérez, Stephen J. Bonasera

Department of Electrical and Computer Engineering: Faculty Publications

Inexpensive, high-throughput, low maintenance systems for precise temporal and spatial measurement of mouse home cage behavior (including movement, feeding, and drinking) are required to evaluate products from large scale pharmaceutical design and genetic lesion programs. These measurements are also required to interpret results from more focused behavioral assays. We describe the design and validation of a highly-scalable, reliable mouse home cage behavioral monitoring system modeled on a previously described, one-ofa- kind system [1]. Mouse position was determined by solving static equilibrium equations describing the force and torques acting on the system strain gauges; feeding events were detected by a photobeam …

Nonlinear Plasmonic Cloaks To Realize Giant All-Optical Scattering Switching, Christos Argyropoulos, Pai-Yen Chen, Francesco Monticone, Giuseppe D'Aguanno, Andrea Alu

Department of Electrical and Computer Engineering: Faculty Publications

Here we extend the reach of Fano resonant coupling by combining this concept with cloaking and plasmonic resonances in a single nonlinear nanoparticle, in order to realize giant all-optical scattering nanoswitches controlled by moderate pumping intensities. We show that a core-shell nonlinear plasmonic particle may be designed to abruptly switch from being completely cloaked to being strongly resonant, with up to a 40 dB cross-sectional difference. Self-tunable optical cloaks and resonant scatterers are envisioned for use as efficient all-optical switches and nanomemories.

Boosting Optical Nonlinearities In E-Near-Zero Plasmonic Channels, Christos Argyropoulos, Pai-Yen Chen, Giuseppe D'Aguanno, Nadar Engheta, Andrea Alu

Department of Electrical and Computer Engineering: Faculty Publications

The anomalous transmission properties of zero-permittivity ultranarrow channels are used to boost Kerr nonlinearities and achieve switching and bistable response for moderate optical intensities. Strong field enhancement, uniform all along the channel, is a typical feature of ε-near-zero supercoupling and is shown to be particularly suited to enhance nonlinear effects. This is obtained by designing narrow apertures at cutoff in a plasmonic screen. We show that this nonlinear mechanism can significantly outperform nonlinearities in traditional Fabry-P´erot resonant gratings.

Laser Induced Breakdown Spectroscopy Having Enhanced Signal-To-Noise Ratio, Dennis R. Alexander, Troy Anderson, John C. Bruce Iii

Department of Electrical and Computer Engineering: Faculty Publications

A material can be analyzed using short pulses by applying a first pulse and a second pulse to the material in which the second pulse is delayed relative to the first pulse. The first and second pulses are directed toward a material along collinear paths, and the material is ablated using the first pulse to cause particles to be emitted from the surface of the material. The emitted particles are atomized and/or ionized using the second pulse, and the radiation from the atomized and/or ionized particles is analyzed.

The Gentle Art Of Mentoring In Higher Education, Nancy H. Barry

To Improve the Academy: A Journal of Educational Development

No abstract provided.

Time To Raise Questions About Student Ratings, Linda B. Nilson

To Improve the Academy: A Journal of Educational Development

No abstract provided.

Understanding Intersecting Processes, Kristen A. Renn

To Improve the Academy: A Journal of Educational Development

No abstract provided.

Empirical Correction For Spectroscopic Ellipsometric Measurements Of Rough Or Textured Surfaces, Craig M. Herzinger, Blaine D. Johs, Mathias M. Schubert, Tino Hofmann

Department of Electrical and Computer Engineering: Faculty Publications

A method of applying spectroscopic ellipsometry to arrive at accurate values of optical and physical properties for thin films on samples having rough or textured surfaces.

Modeling Broad-Scale Patterns Of Avian Species Richness Across The Midwestern United States With Measures Of Satellite Image Texture, Patrick D. Culbert, Volker C. Radeloff, Véronique St-Louis, Curtis H. Flather, Chadwick D. Rittenhouse, Thomas P. Albright, Anna M. Pidgeon

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Avian biodiversity is threatened, and in order to prioritize limited conservation resources and conduct effective conservation planning a better understanding of avian species richness patterns is needed. The use of image texture measures, as a proxy for the spatial structure of land cover and vegetation, has proven useful in explaining patterns of avian abundance and species richness. However, prior studies that modeled habitat with texture measures were conducted over small geographical extents and typically focused on a single habitat type. Our goal was to evaluate the performance of texture measures over broad spatial extents and across multiple habitat types with …

Investigating The Influence Of Lidar Ground Surface Errors On The Utility Of Derived Forest Inventories, Wade T. Tinkham, Alistair M.S. Smith, Chad Hoffman, Andrew T. Hudak, Michael J. Falkowski, Mark E. Swanson, Paul E. Gessler

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Light detection and ranging, or LiDAR, effectively produces products spatially characterizing both terrain and vegetation structure; however, development and use of those products has outpaced our understanding of the errors within them. LiDAR’s ability to capture three-dimensional structure has led to interest in conducting or augmenting forest inventories with LiDAR data. Prior to applying LiDAR in operational management, it is necessary to understand the errors in Li- DAR-derived estimates of forest inventory metrics (i.e., tree height). Most LiDAR-based forest inventory metrics require creation of digital elevation models (DEM), and because metrics are calculated relative to the DEM surface, errors within …

Identifying U.S. First Ladies Involved With Child And Youth Serving Organizations, Greta A. Johnson

Graduate Research Papers

The purpose of this study is to identify how U.S. First Ladies have significantly impacted child or youth programs and causes. This will cover six First Ladies from the 1900's to the present which include: 1) Lou Hoover; 2) Lady Bird Johnson; 4) Nancy Reagan; 3) Barbara Bush; 5) Laura Bush; and 6) Michelle Obama.

Back Pain And Injury Prevalence And Prevention Strategies In The Workplace, Erin Randi Nielsen

Graduate Research Papers

The purpose of this study is to examine the factors and common prevention techniques associated with back pain and injury and provide suggestions for prevention, particularly in the workplace setting.

Forced Wave Motion With Internal And Boundary Damping, Tobias Louw, Scott Whitney, Anu Subramanian, Hendrik J. Viljoen

Papers in Biomolecular Engineering

A d’Alembert-based solution of forced wave motion with internal and boundary damping is presented with the specific intention of investigating the transient response. The dynamic boundary condition is a convenient method to model the absorption and reflection effects of an interface without considering coupled PDE’s. Problems with boundary condition of the form dw/dz+αdw/dt= 0 are not self-adjoint which greatly complicates solution by spectral analysis. However, exact solutions are found with d’Alembert’s method. Solutions are also derived for a time-harmonically forced problem with internal damping and are used to investigate the effect of ultrasound …

Remodeling Of Chromatin Under Low Intensity Diffuse Ultrasound, Sandra Noriega, Gaurav Budhiraja, Anuradha Subramanian

Department of Chemical and Biomolecular Engineering: Faculty Publications

A variety of mechanotransduction pathways mediate the response of fibroblasts or chondrocytes to ultrasound stimulation. In addition, regulatory pathways that co-ordinate stimulus-specific cellular responses are likely to exist. In this study, analysis was confined to the hypothesis that ultrasound stimulation (US) influences the chromatin structure, and that these changes may reflect a regulatory pathway that connects nuclear architecture, chromatin structure and gene expression. Murine fibroblasts seeded on tissue culture plates were stimulated with US (5.0 MHz (14 kPa), 51- s per application) and the thermal denaturation profiles of nuclei isolated from fibroblasts were assessed by dynamic scanning calorimetry (DSC). When …

Integrin-Mediated Mechanotransduction Pathway Of Low-Intensity Continuous Ultrasound In Human Chondrocytes, Nicholas P. Whitney, Allyson C. Lamb, Tobias M. Louw, Anuradha Subramanian

Department of Chemical and Biomolecular Engineering: Faculty Publications

Chondrocytes are mechanosensitive cells that require mechanical stimulation for proper growth and function in in vitro culture systems. Ultrasound (US) has emerged as a technique to deliver mechanical stress; however, the intracellular signaling components of the mechanotransduction pathways that transmit the extracellular mechanical stimulus to gene regulatory mechanisms are not fully defined. We evaluated a possible integrin/mitogen-activated protein kinase (MAPK) mechanotransduction pathway using Western blotting with antibodies targeting specific phosphorylation sites on intracellular signaling proteins. US stimulation of chondrocytes induced phosphorylation of focal adhesion kinase (FAK), Src, p130 Crk-associated substrate (p130Cas), CrkII, and extracellular-regulated kinase (Erk). Furthermore, pre-incubation with inhibitors …

Reconstruction And Comparison Of The Metabolic Potential Of Cyanobacteria Cyanothece Sp. Atcc 51142 And Synechocystis Sp. Pcc 6803, Rajib Saha, Alex T. Verseput, Bertram M. Berla, Thomas J. Mueller, Himadri B. Pakrasi, Costas D. Maranas

Department of Chemical and Biomolecular Engineering: Faculty Publications

Cyanobacteria are an important group of photoautotrophic organisms that can synthesize valuable bio-products by harnessing solar energy. They are endowed with high photosynthetic efficiencies and diverse metabolic capabilities that confer the ability to convert solar energy into a variety of biofuels and their precursors. However, less well studied are the similarities and differences in metabolism of different species of cyanobacteria as they pertain to their suitability as microbial production chassis. Here we assemble, update and compare genome-scale models (iCyt773 and iSyn731) for two phylogenetically related cyanobacterial species, namely Cyanothece sp. ATCC 51142 and Synechocystis sp. PCC 6803. …

Explicit Finite Element Modeling Of The Human Lumbar Spine, Milind Rao

Electronic Theses and Dissertations

Validated finite element (FE) models of the functional spinal unit (FSU) and lumbar spine are essential in design-phase device development and in assessing the mechanics associated with normal spine function and degenerative disc disease (DDD), as well as the impact of fusion and total disc replacement (TDR). Although experimental data from fully intact specimens can be used for model calibration and validation, the contributions from the individual structures (disc, facets, and ligaments) may be inappropriately distributed. Hence, creation of decompression conditions or device implantations that require structure removal may not have the proper resulting mechanics. An explicit FE formulation may …

Overview Of The 2010 Carbonaceous Aerosols And Radiative Effects Study (Cares), Rahul A. Zaveri, William J. Shaw, Daniel J. Cziczo, Beat Schmid, Richard Ferrare, M. Lizabeth Alexander, Raul Alvarez, W. Patrick Arnott, Dean B. Atkinson, Sunil Baidar, Robert M. Banta, James Barnard, Josef Beranek, Larry K. Berg, Fred Brechtel, W. Alan Brewer, John F. Cahill, Brian Cairns, Christopher D. Cappa, D. Chand, S. China, Jennifer M. Comstock, Manvendra K. Dubey, Robert C. Easter, M. H. Erickson, Jerome Fast, Cody Floerchinger, B. Flowers, Edward C. Fortner, Jeffrey S. Gaffney, Mary K. Gilles, Kyle Gorkowski, William Gustafson, Madhu Gyawali, J. Hair, R. M. Hardesty, Joseph Harworth, Scott C. Herndon, Naruki Hiranuma, Chris Hostetler, John M. Hubbe, John T. Jayne, H. Jeong, B. Tom Jobson, Evgueni Kassianov, Lawrence I. Kleinman, C. Kluzek, W. Berk Knighton, Katheryn R. Kolesar, Chongai Kuang, Alena Kubátová, Andrew O. Langford, Alexander Laskin, N. Laulainen, Richard D. Marchbanks, Claudio Mazzoleni, Fan Mei, Ryan C. Moffet, Dan Nelson, Michael Obland, Hilke Oetjen, Timothy B. Onasch, I. Ortega, Matteo Ottaviani, Mikhail Pekour, Kimberly A. Prather, James Gregory Radney, Raymond R. Rogers, Scott P. Sandberg, Arthur J. Sedlacek, Christoph J. Senff, Gunnar I. Senum, Ari Setyan, John E. Shilling, Manishkumar Shrivastava, C. Song, Stephen R. Springston, R. Subramanian, Kaitlyn Suski, Jason Tomlinson, Rainer M. Volkamer, H. W. Wallace, Jian Wang, A. M. Weickmann, Douglas R. Worsnop, Xiao-Ying Yu, Alla Zelenyuk, Qi Zhang

Chemistry Faculty Publications and Presentations

Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic) emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program’s Carbonaceous Aerosol and Radiative Effects Study (CARES) carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was …

Advanced Nanohybrid Materials: Surface Modification And Applications, Li-Hung Liu, Rémi Métivier, Shanfeng Wang, Hui Wang

Chemistry Faculty Publications and Presentations

The field of functional nanoscale hybrid materials is one of the most promising and rapidly emerging research areas in materials chemistry. Nanoscale hybrid materials can be broadly defined as synthetic materials with organic and inorganic components that are linked together by noncovalent bonds (Class I, linked by hydrogen bond, electrostatic force, or van der Waals force) or covalent bonds (Class II) at nanometer scale. The unlimited possible combinations of the distinct properties of inorganic, organic, or even bioactive components in a single material, either in molecular or nanoscale dimensions, have attracted considerable attention. This approach provides an opportunity to create …

Subunit Organization Of The Membrane-Bound Hiv-1 Envelope Glycoprotein Trimer, Youdong Mao, Liping Wang, Christopher Gu, Alon Herschhorn, Shi-Hua Xiang, Hillel Haim, Xinzhen Yang, Joseph Sodroski

Nebraska Center for Virology: Faculty Publications

The trimeric human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) spike is a molecular machine that mediates virus entry into host cells and is the sole target for virus-neutralizing antibodies. The mature Env spike results from cleavage of a trimeric gp160 precursor into three gp120 and three gp41 subunits. Here we describe an ~11-Å cryo-EM structure of the trimeric HIV-1 Env precursor in its unliganded state. The three gp120 and three gp41 subunits form a cage-like structure with an interior void surrounding the trimer axis. Interprotomer contacts are limited to the gp41 transmembrane region, the torus-like gp41 ectodomain, and …

Tennessee Archivist 35, No. 1, Society Of Tennessee Archivists

Tennessee Archivist newsletters

Winter 2012 issue of the Tennessee Archivist, a newsletter produced by the Society of Tennessee Archivists.

Identifying Potential Areas For Biofuel Production And Evaluating The Environmental Effects: A Case Study Of The James River Basin In The Midwestern United States, Yiping Wu, Shuguang Liu, Zhengpeng Li

United States Geological Survey: Staff Publications

Biofuels are now an important resource in the United States because of the Energy Independence and Security Act of 2007. Both increased corn growth for ethanol production and perennial dedicated energy crop growth for cellulosic feedstocks are potential sources to meet the rising demand for biofuels. However, these measures may cause adverse environmental consequences that are not yet fully understood. This study 1) evaluates the long-term impacts of increased frequency of corn in the crop rotation system on water quantity and quality as well as soil fertility in the James River Basin and 2) identifies potential grasslands for cultivating bioenergy …

Insights From A Synthesis Of Old And New Climate-Proxy Data From The Pyramid And Winnemucca Lake Basins For The Period 48 To 11.5 Cal Ka, Larry Benson, J.P. Smoot, S.P. Lund, S.A. Mensing, F.F. Foit Jr., R.O. Rye

United States Geological Survey: Staff Publications

A synthesis of old and new paleoclimatic data from the Pyramid and Winnemucca lake basins indicates that, between 48.0 and 11.5∙10³ calibrated years BP (hereafter ka), the climate of the western Great Basin was, to a degree, linked with the climate of the North Atlantic. Paleomagnetic secular variation (PSV) records from Pyramid Lake core PLC08-1 were tied to the GISP2 ice-core record via PSV matches to North Atlantic sediment cores whose isotopic and(or) carbonate records could be linked to the GISP2δ¹⁸O record. Relatively dry intervals in the western Great Basin were associated with cold Heinrich events and …

Improved Mapping Of National Atmospheric Deposition Program Wet-Deposition In Complex Terrain Using Prism-Gridded Data Sets, Natalie E. Latysh, Gregory Alan Wetherbee

United States Geological Survey: Staff Publications

High-elevation regions in the United States lack detailed atmospheric wet-deposition data. The National Atmospheric Deposition Program/ National Trends Network (NADP/NTN) measures and reports precipitation amounts and chemical constituent concentration and deposition data for the United States on annual isopleth maps using inverse distance weighted (IDW) interpolation methods. This interpolation for unsampled areas does not account for topographic influences. Therefore, NADP/NTN isopleth maps lack detail and potentially underestimate wet deposition in high-elevation regions. The NADP/NTN wet-deposition maps may be improved using precipitation grids generated by other networks. The Parameter-elevation Regressions on Independent Slopes Model (PRISM) produces digital grids of precipitation estimates …

Wildlife Toxicology: Environmental Contaminants And Their National And International Regulation, K. Christiana Grim, Anne Fairbrother, Barnett A. Rattner

United States Geological Survey: Staff Publications

Wildlife toxicology is the study of potentially harmful effects of toxic agents in wild animals, focusing on amphibians, reptiles, birds, and mammals. Fish and aquatic invertebrates are not usually included as part of wildlife toxicology since they fall within the field of aquatic toxicology, but collectively both disciplines often provide inSight into one another and both are integral parts of ecotoxicology (Hoffman et al. 2003). It entails monitoring, hypothesis testing, forensics, and risk assessment; encompasses molecular through ecosystem responses and various research venues (laboratory, mesocosm, field); and has been shaped by chemical use and misuse, ecological mishaps, and biomedical research. …

Development And Application Of Methods Used To Source Prehistoric Southwestern Maize: A Review, Larry Benson

United States Geological Survey: Staff Publications

Archaeological cobs free of mineral contaminants should be used to source the soils in which they were grown. Mineral contaminants often contain much higher concentrations of metals than vegetal materials and can alter a cob’s apparent metal and heavy-isotope content. Cleaning a cob via immersion in an acid solution for more than a few minutes will result in the incongruent and sometimes complete leaching of metals, including strontium (Sr), from the cob. When using ⁸⁷Sr/⁸⁶Sr to determine the location of potential agriculture fields, it is best to either integrate several depth-integrated soil samples or to integrate several …

Metabolic Engineering Of Novel Lignin In Biomass Crops, Ruben Vanholme, Kris Morreel, Chiarina Darrah, Paula Oyarce, John H. Grabber, John Ralph, Wout Boerjan

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Lignin, a phenolic polymer in the secondary wall, is the major cause of lignocellulosic biomass recalcitrance to efficient industrial processing. From an applications perspective, it is desirable that second-generation bioenergy crops have lignin that is readily degraded by chemical pretreatments but still fulfill its biological role in plants. Because plants can tolerate large variations in lignin composition, often without apparent adverse effects, substitution of some fraction of the traditional monolignols by alternative monomers through genetic engineering is a promising strategy to tailor lignin in bioenergy crops. However, successful engineering of lignin incorporating alternative monomers requires knowledge about phenolic metabolism in …

Heme Oxygenase-1 Regulates The Immune Response To Influenza Virus Infection And Vaccination In Aged Mice, Nathan W. Cummins, Eric A. Weaver, Shannon M. May, Anthony J. Croatt, Oded Foreman, Richard B. Kennedy, Gregory A. Polan, Michael A. Barry, Karl A. Nath, Andrew D. Badley

Nebraska Center for Virology: Faculty Publications

Underlying mechanisms of individual variation in severity of influenza infection and response to vaccination are poorly understood. We investigated the effect of reduced heme oxygenase-1 (HO-1) expression on vaccine response and outcome of influenza infection. HO-1-deficient and wild-type (WT) mice (kingdom, Animalia; phylum, Chordata; genus/species, Mus musculus) were infected with influenza virus A/PR/8/34 with or without prior vaccination with an adenoviral-based influenza vaccine. A genome-wide association study evaluated the expression of single-nucleotide polymorphisms (SNPs) in the HO-1 gene and the response to influenza vaccination in healthy humans. HO-1-deficient mice had decreased survival after influenza infection compared to WT mice (median …

Long-Term Impacts Of Invasive Species On A Native Top Predator In A Large Lake System, Scott A. Rush, Gordon Paterson, Tim B. Johnson, Ken G. Drouillard, Gordon D. Haffner, Craig E. Hebert, Michael T. Arts, Daryl J. Mcgoldric, Sean M. Backus, Brian F. Lantry, Jana R. Lantry, Ted Schaner, Aaron T. Fisk

United States Geological Survey: Staff Publications

1. Declining abundances of forage fish and the introduction and establishment of non-indigenous species have the potential to substantially alter resource and habitat exploitation by top predators in large lakes.

2. We measured stable isotopes of carbon (δ¹³C) and nitrogen (δ¹⁵N) in field-collected and archived samples of Lake Ontario lake trout (Salvelinus namaycush) and five species of prey fish and compared current trophic relationships of this top predator with historical samples.

3. Relationships between δ¹⁵N and lake trout age were temporally consistent throughout Lake Ontario and confirmed the role of lake trout …