Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Biomedical Engineering and Bioengineering

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 9781 - 9810 of 11446

Full-Text Articles in Engineering

The Effect Of Water Extracted Silibinin On Reactive Oxygen Species (Ros) Production Of Macrophages, Julie Abbott, Sunny Wallace, Ed Clausen, Danielle Carrier May 2008

The Effect Of Water Extracted Silibinin On Reactive Oxygen Species (Ros) Production Of Macrophages, Julie Abbott, Sunny Wallace, Ed Clausen, Danielle Carrier

Biological and Agricultural Engineering Undergraduate Honors Theses

The world is actively looking for technology to produce sustainable liquid fuels to replace our reliance on petroleum-based fuels. Biomass can be converted either through the thermochemical or saccharification platforms into fuels such as ethanol or butanol. In addition to converting the biomass into liquid fuels, valuable phytochemicals can be extracted prior, during, or after the conversion. Extracting useful phytochemicals, as a part of the overall conversion of biomass to fuels, is included in the concept of the biobased biorefinery. However, the key to effectively and economically extract phytochemicals from biomass is the ability to couple the extraction to the …


Determining The Flow Characteristics Of A Perfusion Device For Donor Heart Transport, Michael Louis Cobert May 2008

Determining The Flow Characteristics Of A Perfusion Device For Donor Heart Transport, Michael Louis Cobert

Bioengineering Theses - Archive

Current technology has limits organ transport for transplantation to static storage, thereby reducing the reasonable distance of travel. Continuous machine perfusion has been proposed as a viable alternative to improving function and outcome. A series of studies with such a device have been developed to elucidate the method by which optimal results can be achieved. Adult mongrel dog hearts were established in a device that provided continuous perfusion of oxygenated fluid and enabled precise control of flow rate, oxygenation, and fluid temperature. The first series of experiments sought to determine an optimal flow rate for tissue perfusion at one of …


Contributions Of Online Visual Feedback To The Learning And Generalization Of Novel Finger Coordination Patterns, Xiaolin Liu, Robert A. Scheidt May 2008

Contributions Of Online Visual Feedback To The Learning And Generalization Of Novel Finger Coordination Patterns, Xiaolin Liu, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

We explored how people learn new ways to move objects through space using neuromuscular control signals having more degrees of freedom than needed to unambiguously specify object location. Subjects wore an instrumented glove that recorded finger motions. A linear transformation matrix projected joint angle signals (a high-dimensional control vector) onto a two-dimensional cursor position on a video monitor. We assessed how visual information influences learning and generalization of novel finger coordination patterns as subjects practiced using hand gestures to manipulate cursor location. Three groups of test subjects practiced moving a visible cursor between different sets of screen targets. The hand-to-screen …


Artificial Neural Network Estimation Of Soil Erosion And Nutrient Concentrations In Runoff From Land Application Areas, Minyoung Kim, John E. Gilley May 2008

Artificial Neural Network Estimation Of Soil Erosion And Nutrient Concentrations In Runoff From Land Application Areas, Minyoung Kim, John E. Gilley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The transport of sediment and nutrients from land application areas is an environmental concern. New methods are needed for estimating soil and nutrient concentrations of runoff from cropland areas on which manure is applied. Artificial Neural Networks (ANNs) trained with a backpropagation (BP) algorithm were used to estimate soil erosion, dissolved P (DP) and NH4–N concentrations of runoff from a land application site near Lincoln, Nebraska, USA. Simulation results from ANN-derived models showed that the amount of soil eroded is positively correlated with rainfall and runoff. In addition, concentrations of DP and NH4–N in overland flow …


Cellular Arrays (Us Patent Application), Angela K. Pannier, Eric A. Ariazi, V. Craig Jordan, Lonnie D. Shea May 2008

Cellular Arrays (Us Patent Application), Angela K. Pannier, Eric A. Ariazi, V. Craig Jordan, Lonnie D. Shea

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The present invention relates to characterizing transcription within cells. In particular, the present invention provides transfected cell arrays (e.g., two-dimensional and/or three-dimensional arrays) and systems, kits and methods utilizing the same (e.g., for transcriptional activity characterization). Compositions and methods of the present invention find use in, among other things, research, drug discovery and clinical (e.g., diagnostic, preventative and therapeutic) applications.


Narrow Grass Hedge Effects On Nutrient Transport Following Compost Application, John E. Gilley, Bahman Eghball, David B. Marx May 2008

Narrow Grass Hedge Effects On Nutrient Transport Following Compost Application, John E. Gilley, Bahman Eghball, David B. Marx

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The placement of stiff‐stemmed grass hedges on the contour along a hillslope has been shown to decrease nutrient transport in runoff. This study was conducted to measure the effectiveness of a narrow grass hedge in reducing runoff nutrient transport from plots with a range of soil nutrient values. Composted beef cattle manure was applied at dry weights of 0, 68, 105, 142, and 178 Mg ha-1 to a silty clay loam soil and then incorporated by disking. Soil samples were collected 243 days later for analysis of water‐soluble phosphorus (WSP), Bray and Kurtz No. 1 phosphorus (Bray‐1 P), NO …


Study Of Electrospinning Of Property-Modulated Biomedical Microfibers, Scott Taylor May 2008

Study Of Electrospinning Of Property-Modulated Biomedical Microfibers, Scott Taylor

All Dissertations

Electrospinning technologies have been of great interest in recent years, due in large part to developments in the field of Bioengineering, including the preparation of novel polymers and advances in tissue engineering, specifically for therapeutic applications. The electrospinning process is, in general, a very benign process that allows the preparation, under mild conditions, of micro- and nano-scale fibers from fiberforming materials, as well as traditionally non-fiber forming materials. This process is of specific interest to the biomedical community because it affords an opportunity to create highly-tailored novel constructs with a multitude of possible uses. Some proposed uses for these materials …


Katp Channel Openers Have Opposite Effects On Mitochondrial Respiration Under Different Energetic Conditions, Matthias L. Riess, Amadou K.S. Camara, André Heinen, Janis T. Eells, Michele M. Henry, David F. Stowe May 2008

Katp Channel Openers Have Opposite Effects On Mitochondrial Respiration Under Different Energetic Conditions, Matthias L. Riess, Amadou K.S. Camara, André Heinen, Janis T. Eells, Michele M. Henry, David F. Stowe

Biomedical Engineering Faculty Research and Publications

Mitochondrial (m) KATP channel opening has been implicated in triggering cardiac preconditioning. Its consequence on mitochondrial respiration, however, remains unclear. We investigated the effects of two different KATP channel openers and antagonists on mitochondrial respiration under two different energetic conditions. Oxygen consumption was measured for complex I (pyruvate/malate) or complex II (succinate with rotenone) substrates in mitochondria from fresh guinea pig hearts. One of two mKATP channel openers, pinacidil or diazoxide, was given before adenosine diphosphate in the absence or presence of an mKATP channel antagonist, glibenclamide or 5-hydroxydecanoate. Without ATP synthase inhibition, both mKATP …


Aquatic Bacteria Removal Using Carbon Nanotubes, Suvish Melanta May 2008

Aquatic Bacteria Removal Using Carbon Nanotubes, Suvish Melanta

Biological and Agricultural Engineering Undergraduate Honors Theses

The purpose of this project is to explore the functionality of carbon nanotubes as a bacterial removal method, specifically towards water-borne bacterial pathogens in wastewater by utilizing its unique magnetic and bacteria-binding properties. The general protocol set for this research follows five steps: 1) Preparation of wastewater media, 2) preparation of CNT culture, 3) preparation of reaction mixture with CNTs for bacterial binding, 4) magnetic separation of bacteria-bound-CNT clusters and, 5) assessment of supernatant. The CNTs effectively removed bacterial contaminants in the wastewater (10%, v/v) after the sand filtration process from the Paul R. Noland Wastewater Facility at Fayetteville, Arkansas. …


Computational Modeling Of Oxidative Stress: An Analysis Of Nad (P)H Effects On Nitric Oxide And Superoxide During Hypertension, Aaron Strobel May 2008

Computational Modeling Of Oxidative Stress: An Analysis Of Nad (P)H Effects On Nitric Oxide And Superoxide During Hypertension, Aaron Strobel

Biological and Agricultural Engineering Undergraduate Honors Theses

Nitric oxide (NO) is inactivated in the human body when exposed to superoxide (O2 -). This reaction forms peroxynitrite (ONOO-). Superoxide is produced in the cardiac system by several different ways, including NAD(P)H oxidase. Superoxide dismutase (SOD) breaks down superoxide into oxygen and hydrogen peroxide. This prevents superoxide from reacting with nitric oxide and allows normal function to take place. Superoxide and peroxynitrite are main contributors to vascular disease in the human body, in particular hypertension. Experiments have shown that there was an increase of superoxide production in spontaneously hypertensive rats (SHR) vs. age-matched Wistar Kyoto rats (WKY) that were …


Developing Lcfs For Biofuels: Getting It Right For Corn Ethanol, Kenneth Cassman, Adam Liska Apr 2008

Developing Lcfs For Biofuels: Getting It Right For Corn Ethanol, Kenneth Cassman, Adam Liska

Adam Liska Papers

• Corn ethanol will be first to test the newly developed LCFS assessment methods; substantial amounts of other biofuels will come several years later

• Accurate valuation of direct-effect GHG emissions from corn ethanol is the foundation of the LCFS process; these affects vary with ethanol biorefinery type and corn feedstock supply

• Different reference GHG emissions values are needed for each major class of ethanol plants

• The BESS model provides the most up-to-date, scientifically sound estimate of corn-ethanol GHG emissions; can BESS and GREET reach agreement?

• Certification and compliance tools are also needed


Fabrication Of Bioactive Osteogenic Controlled-Release Systems, Cellular Platforms, And Cellular Capsules Using Layer -By -Layer Nanoassembly, Skylar Stewart-Clark Apr 2008

Fabrication Of Bioactive Osteogenic Controlled-Release Systems, Cellular Platforms, And Cellular Capsules Using Layer -By -Layer Nanoassembly, Skylar Stewart-Clark

Doctoral Dissertations

There is an ever-increasing awareness that the field of tissue engineering offers many potential solutions to clinical problems. While advances along these lines have been made, the design and implementation of an "off the shelf" tissue is yet to be realized. Thus, the objectives of this work were largely aimed at the design and fabrication of biocompatible, bioactive structures which could be integrated into existing biomaterial products.

The electrostatic layer-by-layer (LbL) self-assembly technique was used to incorporate biologically relevant molecules within controlled release systems, cell culture platforms, and 3-D cellular capsules. Two delivery systems were investigated to determine the release …


Acquisition Of Cardiac Control Parameters From Whole Vagus Nerve Recordings, Marcia A. Pool Apr 2008

Acquisition Of Cardiac Control Parameters From Whole Vagus Nerve Recordings, Marcia A. Pool

Doctoral Dissertations

Heart rate varies continuously depending on the amount of activity being performed or the emotional state of an individual. Both branches of the autonomic nervous system work to alter heart rate depending on the needs of the body. While healthy individuals are capable of altering their heart rate, individuals with certain types of heart disease do not have this ability. For these individuals, cardiac pacemakers are used to alter heart rate. Cardiac pacemakers use sensors to determine the pacing frequency for the heart; however, there is no current optimum sensor. In order to discover a better sensor, this study investigated …


The Processing, Mechanical Properties And Bioactivity Of Strontium Based Glass Polyalkenoate Cements, Anthony Wren, Daniel Boyd, Mark R. Towler Apr 2008

The Processing, Mechanical Properties And Bioactivity Of Strontium Based Glass Polyalkenoate Cements, Anthony Wren, Daniel Boyd, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

The suitability of zinc-based glass polyalkenoate cements (GPCs) for use in orthopaedics can be improved by the substitution of strontium into the glass phase which should impart improved radiopacity and bone forming properties to the cements without retarding strength. The purpose of this research was to produce novel GPCs based on calcium-strontium-zinc-silicate glasses and to evaluate their mechanical properties and biocompatibility with the ultimate objective of developing a new range of cements for skeletal applications. Three glass compositions, based on incremental substitutions of strontium for calcium, were synthesized; BT100 (0.16CaO, 0.36ZnO, 0.48SiO2), BT101 (0.04SrO, 0.12CaO, 0.36ZnO, 0.48SiO2 …


Stochastic Calculations For Computation Of Radiation Effects And Cell Survivability Under Voltage Pulsing, Madhuri Ganapathiraju Apr 2008

Stochastic Calculations For Computation Of Radiation Effects And Cell Survivability Under Voltage Pulsing, Madhuri Ganapathiraju

Electrical & Computer Engineering Theses & Dissertations

Statistical computations are an important tool for the analysis of stochastic phenomena and processes that are characterized by variability. Biological systems (e.g., cells, tissues etc.) are perfect examples wherein response to a given external stimulus can be varied and needs to be adequately considered. The Monte Carlo method of analysis has now been recognized as the most effective way of treating stochastic variability.

This thesis uses Monte Carlo based simulations to probe two problems that require the quantification and modeling of effects caused by energy deposition onto biological matter from external sources. One problem involves the probabilistic study of the …


An Approach To Identifying The Biomechanical Differences Between Intercostal Cartilage In Subjects With Pectus Excavatum And Normals In Vivo: Reconstruction And Ct Registration, Zhenzhen Yan Apr 2008

An Approach To Identifying The Biomechanical Differences Between Intercostal Cartilage In Subjects With Pectus Excavatum And Normals In Vivo: Reconstruction And Ct Registration, Zhenzhen Yan

Electrical & Computer Engineering Theses & Dissertations

Pectus excavatum (PE) is a congenital chest wall deformity affecting the ribs and sternum and exhibiting a concave appearance in the anterior chest wall. In this thesis, we describe a study to investigate in vivo differences in the pectus excavatum rib cage and outline steps using normals and pectus patients data in developing models and methods to be used in carrying out the study. We propose methods to develop reconstructed models in order to enable proper registration between data collection points (DCPs) on the 3D CT rib cage model and CT skin surface model and registration between CT surrogate models …


The Application Of Innovative High-Throughput Techniques To Serum Biomarker Discovery, Izabela Debkiewicz Karbassi Apr 2008

The Application Of Innovative High-Throughput Techniques To Serum Biomarker Discovery, Izabela Debkiewicz Karbassi

Theses and Dissertations in Biomedical Sciences

Time-of-flight mass spectrometry continues to evolve as a promising technique for serum protein expression profiling and biomarker discovery. As seen in our initial SELDI-TOF MS and MALDI-TOF MS profiling study of serum for the assessment of breast cancer risk, many profiling strategies typically employ single chemical affinity beads or surfaces to decrease sample complexity of dynamic fluids like serum. However, most proteins, captured on a particular surface or bead, are not resolved in the lower mass range where mass spectrometers are most effective. To this end we have designed an expression profiling workflow that utilizes immobilized trypsin paramagnetic beads in …


Oxygen Diffusion Through Natural Extracellular Matrices: Implications For Estimating "Critical Thickness" Values In Tendon Tissue Engineering, Caroline Androjna, Jorge E. Gatica, Joanne M. Belovich, Kathleen A. Derwin Apr 2008

Oxygen Diffusion Through Natural Extracellular Matrices: Implications For Estimating "Critical Thickness" Values In Tendon Tissue Engineering, Caroline Androjna, Jorge E. Gatica, Joanne M. Belovich, Kathleen A. Derwin

Chemical & Biomedical Engineering Faculty Publications

Oxygen is necessary for maintaining cell proliferation and viability and extracellular matrix (ECM) production in 3-dimensional tissue engineering. Typically, diffusion is the primary mode for oxygen transport in vitro; thus, ensuring an adequate oxygen supply is essential. In this study, we determined the oxygen diffusion coefficients of 3 natural ECMs that are being investigated as construct scaffolds for tendon tissue engineering: small-intestine submucosa (SIS), human dermis (Alloderm (R)), and canine fascia lata. Diffusion coefficients were determined using a standard diffusion cell system. The ranges for each matrix type were: SIS: 7 x 10(-6) - 2 x 10(-5) cm(2)/s, Alloderm (R): …


Comparison Of An Experimental Bone Cement With Surgical Simplex® P, Spineplex® And Cortoss®, D. Boyd, Mark R. Towler, A. Wren, O. M. Clarkin Apr 2008

Comparison Of An Experimental Bone Cement With Surgical Simplex® P, Spineplex® And Cortoss®, D. Boyd, Mark R. Towler, A. Wren, O. M. Clarkin

Chemical and Biochemical Engineering Faculty Research & Creative Works

Conventional polymethylmethacrylate (PMMA) cements and more recently Bisphenol-a-glycidyl dimethacrylate (BIS-GMA) composite cements are employed in procedures such as vertebroplasty. Unfortunately, such materials have inherent drawbacks including, a high curing exotherm, the incorporation of toxic components in their formulations, and critically, exhibit a modulus mismatch between cement and bone. The literature suggests that aluminum free, zinc-based glass polyalkenoate cements (Zn-GPC) may be suitable alternative materials for consideration in such applications as vertebroplasty. This paper examines one formulation of Zn-GPC and compares its strengths, modulus, and biocompatibility with three commercially available bone cements, Spineplex®, Simplex® P and Cortoss®. The setting times indicate …


Bioresorbable Polylactide Interbody Implants In An Ovine Anterior Cervical Discectomy And Fusion Model: Three-Year Results, Kevin A. Thomas, Jeffrey M. Toth, Neil R. Crawford, Howard Seim, Lewis L. Shi, Mitchel B. Harris, Anthony S. Turner Apr 2008

Bioresorbable Polylactide Interbody Implants In An Ovine Anterior Cervical Discectomy And Fusion Model: Three-Year Results, Kevin A. Thomas, Jeffrey M. Toth, Neil R. Crawford, Howard Seim, Lewis L. Shi, Mitchel B. Harris, Anthony S. Turner

Biomedical Engineering Faculty Research and Publications

Study Design.

In vivo study of anterior discectomy and fusion using a bioresorbable 70:30 poly(l-lactide-co-d,l-lactide) interbody implant in an ovine model.

Objective.

To evaluate the efficacy of the polylactide implant to function as an interbody fusion device, and to assess the tissue reaction to the material during the resorption process.

Summary of Background Data.

The use of polylactide as a cervical interbody implant has several potential advantages when compared with traditional materials. Having an elastic modulus very similar to bone minimizes the potential for stress shielding, and as the material resorbs additional loading is transferred to the developing fusion mass. …


Modeling Electric Fields In Microfluidic Devices, Micah Fincher Apr 2008

Modeling Electric Fields In Microfluidic Devices, Micah Fincher

Honors Capstones

No abstract provided.


Real-Time Ultrasound Simulation For Medical Training And Standardized Patient Assessment, Bo Sun Apr 2008

Real-Time Ultrasound Simulation For Medical Training And Standardized Patient Assessment, Bo Sun

Computational Modeling & Simulation Engineering Theses & Dissertations

With the increasing role played by ultrasound in clinical diagnostics, ultrasound training in medical education has become more and more important. The clinical routine for ultrasound training is on real patients; therefore monitored and guided examinations involving medical students are quite time-constrained. Furthermore, standardized patients (SPs), who are increasingly used in medical school for teaching and assessing medical students, need to be augmented. These SPs are typically healthy individuals who can not accurately portray the variety of abnormalities that are needed for training especially when medical examinations involve instrument interactions. To augment SPs in a realistically effective way and also …


Caffeine Model Identification For Vigilance Performance Prediction, Chun-Hui Huang Apr 2008

Caffeine Model Identification For Vigilance Performance Prediction, Chun-Hui Huang

Mechanical & Aerospace Engineering Theses & Dissertations

The pharmacodynamics and pharmacokinetics of caffeine have been well characterized. In this study, a caffeine dynamic model is developed to describe its pharmacodynamic effects on vigilance performance. Validated biomathematical models developed to address both individual and group fatigue and alertness in a non-laboratory setting represent a tremendous commercial opportunity. First, a test data set with caffeine effects isolated from circadian and homeostatic effects is created. Then a modeling approach for input and output effects is developed and different model structures for the caffeine effects are considered. Observer/Kalman filter Identification (OKID) algorithm is proposed and developed to identify the caffeine model …


An Adaptive Neuro-Fuzzy Inference System For Modeling Mechanical Properties Of Tapioca Starch-Poly(Lactic Acid) Nanocomposite Foams, Siew-Yoong Lee, Milford Hanna, David D. Jones Mar 2008

An Adaptive Neuro-Fuzzy Inference System For Modeling Mechanical Properties Of Tapioca Starch-Poly(Lactic Acid) Nanocomposite Foams, Siew-Yoong Lee, Milford Hanna, David D. Jones

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Tapioca starch, poly(lactic acid) and Cloisite 30B nanocomposites foams, with clay contents of 1, 3, 5 and 7% (w/w), were prepared by a meltintercalation method. Multiple inputs single output models were developed to predict radial expansion ratio, unit density, bulk compressibility and spring index of the nanocomposite foams. An individual ANFIS model was developed for each mechanical property using clay content, temperature, pressure and torque as input parameters. All models preformed well with R2 values > 0.71. All models had very low root mean squared error values.


Force Measurement And Evaluation For Surgical Cutting Applications: Development Of An Effective Characterisation Testbed, Dean Callaghan Mar 2008

Force Measurement And Evaluation For Surgical Cutting Applications: Development Of An Effective Characterisation Testbed, Dean Callaghan

Conference Papers

Sensorized instruments that cater for accurate measurement of the interaction forces (between biological tissue and instrument end-effector) during surgical procedures offer surgeons a greater sense of immersion during minimally invasive robotic surgery (MIRS). There is much ongoing research into force measurement/evaluation involving surgical graspers. However, comparatively little corresponding effort has been expended in the measurement and subsequent evaluation of forces between scissor blades and tissue. This paper presents the design and development of a force/strain measurement test apparatus, which will ultimately serve as an effective sensor characterisation and evaluation platform. Data acquired from the testing platform can be used to …


Spatial Variations In Nutrient And Microbial Transport From Feedlot Surfaces, John E. Gilley, Elaine D. Berry, Roger A. Eigenberg, David B. Marx, Bryan L. Woodbury Mar 2008

Spatial Variations In Nutrient And Microbial Transport From Feedlot Surfaces, John E. Gilley, Elaine D. Berry, Roger A. Eigenberg, David B. Marx, Bryan L. Woodbury

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Nutrient and microbial transport by runoff may vary at different locations within a beef cattle feedlot. If the areas making the largest contributions to nutrient and microbial transport can be identified, it may be possible to institute site‐specific management practices to reduce runoff nutrient and microbial transport. The objectives of this study were to: (1) measure selected feedlot soil properties and nutrient and microbial transport in runoff from various feedlot locations, (2) compare the effects of unconsolidated surface materials (USM) (loose manure pack) and consolidated subsurface materials (CSM) (compacted manure and underlying layers) on nutrient and microbial transport, and (3) …


An Effect Of Relative Motion On Trajectory Discrimination, Scott A. Beardsley, Lucia M. Vaina Mar 2008

An Effect Of Relative Motion On Trajectory Discrimination, Scott A. Beardsley, Lucia M. Vaina

Biomedical Engineering Faculty Research and Publications

Psychophysical studies point to the existence of specialized mechanisms sensitive to the relative motion between an object and its background. Such mechanisms would seem ideal for the motion-based segmentation of objects; however, their properties and role in processing the visual scene remain unclear. Here we examine the contribution of relative motion mechanisms to the processing of object trajectory. In a series of four psychophysical experiments we examine systematically the effects of relative direction and speed differences on the perceived trajectory of an object against a moving background. We show that background motion systematically influences the discrimination of object direction. …


The Role Of Sr²⁺ On The Structure And Reactivity Of Sro-Cao-Zno-Sio2 Ionomer Glasses, Daniel Boyd, Mark R. Towler, Sally Watts, Robert G. Hill, Anthony W. Wren, Owen M. Clarkin Feb 2008

The Role Of Sr²⁺ On The Structure And Reactivity Of Sro-Cao-Zno-Sio2 Ionomer Glasses, Daniel Boyd, Mark R. Towler, Sally Watts, Robert G. Hill, Anthony W. Wren, Owen M. Clarkin

Chemical and Biochemical Engineering Faculty Research & Creative Works

The suitability of Glass Polyalkenoate Cements (GPCs) for use in orthopaedics is retarded by the presence in the glass phase of aluminum, a neurotoxin. Unfortunately, the aluminum ion plays an integral role in the setting process of GPCs and its absence is likely to hinder cement formation. However, the authors have previously shown that aluminum free GPCs may be formulated based on calcium zinc silicate glasses and these novel materials exhibit significant potential as hard tissue biomaterials. To further improve their potential and given that Strontium (Sr) based drugs have had success in the treatment of osteoporosis, the authors have …


Tem Analysis Of Apatite Surface Layers Observed On Zinc Based Glass Polyalkenoate Cements, D. Boyd, Mark R. Towler, A. W. Wren, O. M. Clarkin, D. A. Tanner Feb 2008

Tem Analysis Of Apatite Surface Layers Observed On Zinc Based Glass Polyalkenoate Cements, D. Boyd, Mark R. Towler, A. W. Wren, O. M. Clarkin, D. A. Tanner

Chemical and Biochemical Engineering Faculty Research & Creative Works

The amorphous nature and composition of the surface apatite layers observed on glass polyalkenoate cements based on zinc silicate glasses (Zn-GPCs) after immersion in simulated body fluid (SBF) have been analyzed by the transmission electron microscopy (TEM). TEM was conducted using a JEOL JEM-2011 electron microscope operated at an accelerating voltage of 200 kV. The composition elements of the surface layer indicated the presence of calcium, phosphorous, zinc, and strontium within the amorphous structure. This composition, in particular the inclusion of Zn in the structure, indicates the lack of crystallinity associated with the formation of the apatite layers observed on …


Leg Sympathetic Response To Noxious Skin Stimuli Is Similar In High And Low Level Human Spinal Cord Injury, M. Kevin Garrison, Alexander V. Ng, Brian D. Schmit Feb 2008

Leg Sympathetic Response To Noxious Skin Stimuli Is Similar In High And Low Level Human Spinal Cord Injury, M. Kevin Garrison, Alexander V. Ng, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

Objective

To determine if sympathetically mediated vasoconstriction in the lower extremities is injury level dependent. Although sympathetic responses have been measured in the limbs of people with high and low level SCI using blood flow measurements, including Doppler ultrasound and venous plethysmography, a direct comparison between injury levels has not been made.

Methods

Volunteers with chronic SCI were grouped according to injury level. Above T6: high level (HL, n = 7), and T6 and below: low level (LL, n = 6). All subjects had complete motor and sensory loss. Leg arterial flows were recorded by venous occlusion plethysmography, and continuous …