Digital Commons Network^™

Mechanical Behavior And Length Adaptation Of Rabbit Bladder Smooth Muscle, Atheer Almasri

Theses and Dissertations

Overactive bladder (OAB), involuntary contractions during bladder filling, is a common condition affecting 17% of the adult population worldwide, and in the U.S. ranks ahead of diabetes in a list of the 10 most common chronic disorders (Mullins 2009). Mechanical mechanisms contributing to OAB are not completely understood and because of the unique function and broad volume range of the bladder, there may be mechanical characteristics that distinguish detrusor smooth muscle (DSM) in bladder from other smooth muscles. Recent studies have shown that the length-passive tension curve in DSM exhibits adjustable passive stiffness (APS) characterized by a passive curve that …

Differential Eeg, Sheng Feng Yen, Daniel Schoonover, Justin C. Sanchez, Jose C. Principe, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

We propose to improve the spatial resolution of electroencephalography (EEG) using a differential recording methodology. Conventional EEG (CEEG) systems independently amplify and digitize the signal from each electrode. The Differential EEG (DEEG) approach amplifies the minute difference signal between neighboring electrodes which greatly eases the burden on the subsequent amplification and data conversion stages. A custom DEEG system was designed and fabricated in a 0.6 um CMOS process. The fabricated chip was built into a small prototype DEEG recording system used to measure alpha waves from the occipital lobe of a human subject. We show that the differential approach suffers …

An Integrated Recording System Using An Asynchronous Pulse Representation, Sheng Feng Yen, Jie Xu, Manu Rastogi, John G. Harris, Jose C. Principe, Justin C. Sanchez

Electrical and Computer Engineering Faculty Research & Creative Works

A neuronal recording system for brain-machine interfaces (BMI) based on asynchronous biphasic pulse coding is described. It demonstrates the first step in the development of a complete implanted wireless solution with fully integrated circuit architecture. A recording experiment comparing in parallel a commercial recording system (Tucker-Davis Technology (TDT)) and the UF's custom solution (FWIRE) is set up to compare performance. The novel aspect of the UF system is that the analog signal is represented by an asynchronous pulse train, which provides a low-power, low-bandwidth, noise-resistant means for coding and transmission. Taking advantage of neural firing features, the pulse-based approach uses …

Periodicity Detection And Localization Using Spike Timing From The Aer Ear, Theodore Yu, Andrew Schwartz, John Harris, Malcolm Slaney, Shih Chii Liu

Electrical and Computer Engineering Faculty Research & Creative Works

We present a system consisting of a spiking cochlea chip and real-time event-based processing software that is able to discriminate between two sets of sounds based on their periodicity content. The periodicity measurements are computed from the spike timing information of asynchronous output spikes from the binaural spiking-cochlea chip. The chip consists of a matched pair of silicon cochlea with an address event interface for the output. Each section of the cochlea is modeled by a second-order low-pass filter followed by a simplified Inner Hair Cell circuit and a Spiking Neuron circuit. We show discrimination results using the periodicity measure …

Biologically Plausible Speech Recognition Using Spike-Based Phase Locking Cues, Ismail Uysal, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

A biologically plausible algorithm is proposed for phoneme recognition that makes use of spikes for computation. The prototype system is demonstrated on voiced phonemes and shows competitive performance with state-of-the-art systems on a vowel dataset in the presence of noise. Using novel phase locking cues, the algorithm performs surprisingly well down to SNR values as low as 5dB, where the performance of the baseline algorithm used for comparison drops considerably. These results suggest, not only a possible explanation for the extreme noise robustness of human recognition, but also a novel technique for information processing for speech signals with computers. ©2009 …

A Biphasic Integrate-And-Fire System, Sheng Feng Yen, Jie Xu, Manu Rastogi, John G. Harris, Jose C. Principe, Justin C. Sanchez

Electrical and Computer Engineering Faculty Research & Creative Works

A neuronal recording system for brain-machine interfaces (BMI) based on asynchronous biphasic pulse coding is described. It demonstrates the first step in the development of a completely implanted wireless solution with a fully integrated circuit architecture. A recording experiment comparing, in parallel, a commercial recording system (Tucker-Davis Technology (TDT)) and the UF's custom solution (FWIRE) is set up to compare performance. The novel aspect of the UF system is that the analog signal is represented by an asynchronous pulse train, which provides a low-power, low-bandwidth, noise resistant means for coding and transmission. Taking advantage of neural firing features, the pulse-based …

In-Plane All-Photonic Transduction With Differential Splitter Using Double-Step Rib Waveguide For Photonic Microcantilever Arrays, Ryan Anderson, Seunghyun Kim, Gregory P. Nordin, Jong Wook Noh, Weisheng Hu

Faculty Publications

We report a differential splitter consisting of an asymmetric double-step multimode rib waveguide and a Y-branch splitter for in-plane photonic transduction of photonic microcantilever deflection. Arrays of photonic microcantilevers are integrated with differential splitters and an optical waveguide network to demonstrate uniformity and sensitivity of transduction. Measurement results from multiple arrays indicate a sensitivity of 0.32 x 10-3 nm-1 and minimum detectable deflection of 141 pm for a 3.5 Hz measurement bandwidth.

Methods And Devices For Cryopreservation Of Biological Cells And Tissues, Dayong Gao, Gary Van Zant, Xiangdong Cui

Mechanical Engineering Faculty Patents

Novel methods, compositions, and devices for achieving optimal cooling of living cells during cryopreservation are disclosed. In one aspect, the method comprises gradually cooling the cell to a first predetermined temperature, followed by rapidly cooling the cell to a second predetermined temperature. In another aspect, a device is described for achieving a desired cooling rate for a cell, comprising a first container for holding a cell, a second container for holding the first container, and optionally a frame for holding the first container in a spaced apart relationship with the second container. The method of the invention comprises placing cells …

Fabrication Of High-Capacity Biomolecular Carriers From Dispersible Single-Walled Carbon Nanotube-Polymer Composites, Pu Zhang, David B. Henthorn

Chemical and Biochemical Engineering Faculty Research & Creative Works

One of the most interesting applications for carbon nanotubes is as a support material for bioanalytical devices. in this work, we successfully used an ultraviolet light initiated "graft from" polymerization method to fabricate polymer functionalized carbon nanotubes (PFCNTs) with pendant chains of various functionalities, including poly (ethylene glycol) chains to boost dispersibility and pendant epoxy groups for protein conjugate sites. a model enzyme, alkaline phosphatase, was used to study biomolecule loading efficiency as well as the retention of enzyme activity. Samples with various ratios of the two monomers were fabricated to optimize their use in aqueous environments, and an optimal …

Nutrient Removal & Greenhouse Gas Abatement With Co2 Supplemented Algal High Rate Ponds, Ian Woertz, Laura Fulton, Tryg Lundquist

Civil and Environmental Engineering

High rate algae ponds fed clarified domestic wastewater and CO₂-rich flue gas are expected to remove nutrients to concentrations similar to those achieved in mechanical treatment technologies, such as activated sludge. However, the energy intensity of wastewater treatment with CO₂-supplemented high rate ponds (HRPs) would be less than that of mechanical treatments. In conjunction with anaerobic digestion of algal biomass and co-substrates, the algae-based system would produce a substantial excess of electricity. Greenhouse gas abatement from such CO₂-HRP/digestion systems would stem mainly from energy conservation and the offset of fossil fuel electricity with biogas-derived …

Biogas Production From Algae Biomass Harvested At Wastewater Treatment Ponds, Michael Salerno, Yakup Nurdogan, Tryg J. Lundquist

Civil and Environmental Engineering

Waste-grown microalgae are a potentially important biomass for biofuel production. However, most of the 7,000 wastewater treatment ponds systems in the US do not use algae harvesting. Those that do, typically return the biomass to the ponds, where it decomposes on the pond floor, releasing methane to the atmosphere and degrading water quality. Instead, the algae biomass could be processed in anaerobic digesters. Algae typically yield less methane than wastewater sludge (~0.3 vs. 0.40 L CH4/g volatile solids introduced). Ammonia toxicity and recalcitrant cell walls are commonly cited causes of the lower yields. Ammonia toxicity might be counteracted by co-digesting …

Beyond Biobricks: Synthesizing Synergistic Biochemical Systems From The Bottom-Up, Mark A. Bedau

Systems Science Friday Noon Seminar Series

Engineers who attempt to discover and optimize the behavior of complex biochemical systems face a dauntingly difficult task. This is especially true if the systems are governed by multiple qualitative and quantitative variables that have non-linear response functions and that interact synergistically. The synthetic biology community has responded to this difficulty by promoting the use of "standard biological parts" called "BioBricks", which are supposed to make biology into traditional engineering and enable engineers to "program living organisms in the same way a computer scientists can program a computer". But the BioBricks research program faces daunting hurdles, because the nonlinearity and …

Sharing Landmark Information Using Mixture Of Gaussian Terrain Spatiograms, Damian M. Lyons

Faculty Publications

In this paper we evaluate the use of a novel spatial histogram called the terrain spatiogram as a common representation for exchanging landmark information between robots working as a team to map an area. Individual robots use range sensors to provide the spatial dimension of the spatiogram and video for the image dimension. We have previously shown that terrain spatiograms can be shared between robots in a heterogeneous team to recognize landmarks and to fuse observations from multiple sensors or multiple platforms. A terrain spatiogram using a mixture of Gaussians (MOG) model is introduced and a corresponding normalized spatiogram similarity …

Material Properties Are Related To Stress Fracture Callus And Porosity Of Cortical Bone Tissue At Affected And Unaffected Sites, Rachel C. Entwistle,, Sara C. Sammons, Robert F. Bigley, Scott J. Hazelwood, David P. Fyhrie, Jeffery C. Gibeling, Susan M. Stover

Biomedical Engineering

Stress fractures are overuse injuries of bone that affect elite athletes and military recruits. One response of cortical bone to stress fracture is to lay down periosteal callus. The objectives of this study were to determine if material properties are different among bones with different stages of stress fracture callus, at both a callus site and at a distal site. Cortical specimens were mechanically tested to determine their stress–strain response. Material property differences were examined using nonparametric and regression analyses. At the callus site, material properties were low during the earliest stages of callus, higher with increasing callus maturity, but …

P300-Based Speller Brain-Computer Interface, Reza Fazel-Rezai

Electrical Engineering Faculty Publications

No abstract provided.

Improvement Of Eeg Based Brain Computer Interface By Application Of Tripolar Electrodes And Independent Component Analysis, Hongbao Cao

Doctoral Dissertations

For persons with severe disabilities, a brain computer interface (BCI) may be a viable means of communication, with scalp-recorded electroencephalogram (EEG) being the most common signal employed in the operation of a BCI. Various electrode configurations can be used for EEG recording, one of which was a set of concentric rings that was referred to as a Laplacian electrode. It has been shown that Lapalacian EEG could improve classification in EEG recognition, but the complete advantages of this configuration have not been established.

This project included two parts. First, a modeling study was performed using Independent Component Analysis (ICA) to …

Radiation Detectors And Sources Enhanced With Micro/Nanotechnology, Chad Michael Whitney

Doctoral Dissertations

The ongoing threat of nuclear terrorism presents major challenges to maintaining national security. Currently, only a small percentage of the cargo containers that enter America are searched for fissionable bomb making materials. This work reports on a multi-channel radiation detection platform enabled with nanoparticles that is capable of detecting and discriminating all types of radiation emitted from fissionable bomb making materials. Typical Geiger counters are limited to detecting only beta and gamma radiation. The micro-Geiger counter reported here detects all species of radiation including beta particles, gamma/X-rays, alpha particles, and neutrons. The multi-species detecting micro-Geiger counter contains a hermetically sealed …

Numerical Simulation Of Gas-Phonon Coupling In Thermal Transpiration Flows, Xiaohui Guo, Dhruv Singh, Jayathi Murthy, Alina A. Alexeenko

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

Thermal transpiration is a rarefied gas flow driven by a wall temperature gradient and is a promising mechanism for gas pumping without moving parts, known as the Knudsen pump. Obtaining temperature measurements along capillary walls in a Knudsen pump is difficult due to extremely small length scales. Meanwhile, simplified analytical models are not applicable under the practical operating conditions of a thermal transpiration device, where the gas flow is in the transitional rarefied regime. Here, we present a coupled gas-phonon heat transfer and flow model to study a closed thermal transpiration system. Discretized Boltzmann equations are solved for molecular transport …

Sers In Salt Wells, G. V. Pavan Kumar, Joseph Irudayaraj

Birck and NCN Publications

We report herein a simple, inexpensive fabrication methodology of salt microwells, and define the utility of the latter as nanoparticle containers for highly sensitive surface-enhanced Raman scattering (SERS) studies. AFM characterization of Ag and Au loaded salt microwells reveal the ability to contain favorable nanostructures such as nanoparticle dimers, which can significantly enhance the Raman intensity of molecules. By performing diffraction-limited confocal Raman microscopy on salt microwells, we show high sensitivity and fidelity in the detection of dyes, peptides, and proteins, as a proof of our concept. The SERS limit of detection (accumulation time of 1 s) for rhodamine B …

Compression After Impact Load Prediction In Graphite/Epoxy Laminates Using Acoustic Emission And Artificial Neural Networks, Anthony Michael Gunasekera

Master's Theses - Daytona Beach

The purpose of this research was to investigate the effectiveness of artificial neural networks (ANNs) in predicting the compression after impact (CAI) load of graphite/epoxy laminates from acoustic emission (AE) nondestructive testing (NDT) data. Thirty-four 24-ply bidirectional woven cloth laminate coupons were constructed and impacted at various energy levels ranging from 8 to 20 Joules, generating barely visible impact damage (BVID). Acoustic emission data were acquired as the coupons were compressed to failure. Not having been analyzed by previous experimenters, several noise tests were also performed to determine the impact of external noise on acoustic emission data during testing. Once …

Nebraska Blueprint- Fall 2009

Nebraska Blueprint (Student Publication)

Table of Contents:

From the Editor

Then and Now

Engineering Block: A History of Home

College of Engineering Timeline

Longtime Professors Leave Lasting Impact

IEEE 125th Anniversary Celebration

Nonlinearity In Large Amplitude Oscillatory Shear (Laos) Of Different Viscoelastic Materials, Xin Li, Shi-Qing Wang, Xiaorong Wang

College of Polymer Science and Polymer Engineering

The present work investigates nonlinear behavior in large amplitude oscillatory shear (LAOS) of four different polymeric materials using simultaneous conventional rheometric measurements and particle-tracking velocimetric observations. In contrast to most studies in the literature that treat nonlinearity in LAOS in steady state, we emphasize by the present four examples that nonlinearity in LAOS often arise in complex fluids due to time-dependent rearrangement of their microstructures in response to LAOS. Consequently, no correlation is obvious between strain dependence of the steady-state stress response and the time-dependent characteristics of the steady-state response. For instance, a highly viscoelastic material made of nano-sized polybutadiene …

Compliance Calibration For Fracture Testing Of Anisotropic Biological Materials, J. A. Creel, S. M. Stover, R. B. Martin, D. P. Fyhrie, S. J. Hazelwood, J. C. Gibeling

Biomedical Engineering

The compliance technique has been used to monitor crack length during fracture and fatigue testing of materials. Difficulties arise when this technique is applied to anisotropic biological materials such as bone. In this tutorial, two different methods of analyzing compliance calibration data are described: the standard ASTM method and a new approach developed by the authors specifically for anisotropic materials. An example is given showing how data from equine cortical bone can be analyzed. In this example, calibration tests were conducted on thirty-six three point bend specimens machined from the middiaphysis of six pairs of equine third metacarpal bones. Cracks …

Cs/Bio 471/671: Algorithms For Bioinformatics, Michael L. Raymer

Computer Science & Engineering Syllabi

Theory-oriented approach to the application of contemporary algorithms to bioinformatics. Graph theory, complexity theory, dynamic programming and optimization techniques are introduced in the context of application toward solving specific computational problems in molecular genetics. 4 credit hours.

A Nonlinear Constituent Based Viscoelastic Model For Articular Cartilage And Analysis Of Tissue Remodeling Due To Altered Glycosaminoglycan-Collagen Interactions, Gregory C. Thomas, Anna Asanbaeva, Pasquale Vena, Robert L. Sah, Stephen M. Klisch

Mechanical Engineering

A constituent based nonlinear viscoelastic (VE) model was modified from a previous study (Vena, et al., 2006, “A Constituent-Based Model for the Nonlinear Viscoelastic Behavior of Ligaments,” J. Biomech. Eng., 128, pp. 449–457) to incorporate a glycosaminoglycan (GAG)-collagen (COL) stress balance using compressible elastic stress constitutive equations specific to articular cartilage (AC). For uniaxial loading of a mixture of quasilinear VE constituents, time constant and relaxation ratio equations are derived to highlight how a mixture of constituents with distinct quasilinear VE properties is one mechanism that produces a nonlinear VE tissue. Uniaxial tension experiments were performed with newborn bovine AC …

A Biomechanical Comparison Of Locked Plate Fixation With Percutaneous Insertion Capability Versus The Angled Blade Plate In A Subtrochanteric Fracture Gap Model, Brett D. Crist, Afshin Khalafi, Scott J. Hazelwood, Mark A. Lee

Biomedical Engineering

Objectives: The angled blade plate has been the historical standard in fixed-angle extramedullary subtrochanteric femur fracture fixation, but it requires an extensile lateral approach to the femur. Little formal evaluation exists for specifically designed percutaneous extramedullary implants. The purpose of this study was to compare 3 locked plating constructs, all with percutaneous insertion capability, with the standard 95-degree angled blade plate to determine whether specifically designed fixed-angle extramedullary implants for subtrochanteric femur fractures were biomechanically comparable to the angled blade plate.

Methods: Forty composite adult femurs were divided into 4 equal groups. The constructs evaluated included a 95-degree angled blade …

Identification Of The [Fefe]-Hydrogenase Responsible For Hydrogen Generation In Thermoanaerobacterium Saccharolyticum And Demonstration Of Increased Ethanol Yield Via Hydrogenase Knockout, A. Joe Shaw, David A. Hogsett, Lee R. Lynd

Dartmouth Scholarship

Three putative hydrogenase enzyme systems in Thermoanaerobacterium saccharolyticum were investigated at the genetic, mRNA, enzymatic, and phenotypic levels. A four-gene operon containing two [FeFe]-hydrogenase genes, provisionally termed hfs (hydrogenase-Fe-S), was found to be the main enzymatic catalyst of hydrogen production. hfsB, perhaps the most interesting gene of the operon, contains an [FeFe]-hydrogenase and a PAS sensory domain and has several conserved homologues among clostridial saccharolytic, cellulolytic, and pathogenic bacteria. A second hydrogenase gene cluster, hyd, exhibited methyl viologen-linked hydrogenase enzymatic activity, but hyd gene knockouts did not influence the hydrogen yield of …

Regression Analysis Of Fracture Toughness For Secondary Osteons Located In Human Cortical Bone, Chase A. Fetzer

Master's Theses

An experiment was carried out in order to locate and quantify osteon types within a sample of cortical bone taken from a human tibia. This was done using a microscope-camera assembly and the BioQuant computer software. The results of this were correlated with a previous experiment’s results on fracture toughness so that an analysis could be run on the data in order to determine the factors that most affect the value of fracture toughness of this cortical bone. Results were examined closely and the analysis repeated until the author was satisfied that the best possible model for fracture toughness had …

Sharing Mobile Multimedia Annotations To Support Inquiry-Based Learning Using Mobitop, Khasfariyati Razikin, Dion Hoe-Lian Goh, Yin-Leng Theng, Quang Minh Nguyen, Thi Nhu Quynh Kim, Ee Peng Lim, Chew-Hung Chang, Kalyani Chatterjea, Aixin Sun

Research Collection School Of Computing and Information Systems

Mobile devices used in educational settings are usually employed within a collaborative learning activity in which learning takes place in the form of social interactions between team members while performing a shared task. We introduce MobiTOP (Mobile Tagging of Objects and People), a geospatial digital library system which allows users to contribute and share multimedia annotations via mobile devices. A key feature of MobiTOP that is well suited for collaborative learning is that annotations are hierarchical, allowing annotations to be annotated by other users to an arbitrary depth. A group of student-teachers involved in an inquiry-based learning activity in geography …

Splenic Trauma As An Adverse Effect Of Torso-Protecting Side Airbags: Biomechanical And Case Evidence, Jason John Hallman, Karen J. Brasel, Narayan Yoganandan, Frank A. Pintar

Biomedical Engineering Faculty Research and Publications

Injury mechanisms from frontal airbags, first identified in anecdotal reports, are now well documented for pediatric, small female, and out-of-position occupants. In contrast, torso side airbags have not yet been consistently associated with specific injury risks in field assessments. To determine possible torso side airbag-related injuries, the present study identified crashes involving side airbags from reports within the CIREN, NASS, and SCI databases. Injury patterns were compared to patterns from lateral crashes in absence of side airbag. Splenic trauma (AIS 3+) was found present in five cases of torso side airbag deployment at lower impact severity (as measured by velocity …