Engineering Commons^™

Quantitative Regional Associations Between Remodeling, Modeling, And Osteocyte Apoptosis And Density In Rabbit Tibial Midshafts, Nicole L. Hedgecock, Tamer Hadi, Andrew A. Chen, Shane B. Curtiss, R. Bruce Martin, Scott J. Hazelwood

Biomedical Engineering

Evidence suggests that osteocyte apoptosis is involved in the adaptive response of bone, although the specific role of osteocytes in the signaling mechanism is unknown. Here, we examined and correlated regional variability in indices of remodeling, modeling, osteocyte apoptosis, and osteocyte density in rabbit tibia midshafts. Histomorphometric analysis indicated that remodeling parameters (BMU activation frequency, osteon density, forming osteon density, and resorption cavity density) were lower in the cranial region compared to other quadrants. In addition, pericortical subregions displayed less remodeling relative to intracortical and endocortical ones. Modeling indices also demonstrated regional variability in that periosteal surfaces exhibited a greater …

Crop Residue Effects On Runoff Nutrient Concentrations Following Manure Application, Jeffrey E. Nicolaisen, John E. Gilley, Bahman Eghball, David B. Marx

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Manure is applied to cropland areas managed under diverse conditions, resulting in varying amounts of residue cover. The objective of this study was to measure the effects of crop residue on nutrient concentrations in runoff from areas where beef cattle or swine manure were recently applied but not incorporated. Plots 0.75 m wide by 2 m long were established at the study site. Existing residue materials were removed, and corn, soybean, or winter wheat residue was added at rates of 2, 4, or 8 Mg ha⁻¹. Manure was then applied at rates required to meet estimated annual nitrogen …

Selective Assembly Of Nanoparticles On Block Copolymer By Surface Modification, Sanjun Niu, Ravi F. Saraf

Ravi Saraf Publications

We have developed a method to selectively deposit nanoparticles on the ordered nanoscale elements of PS–PI–PS (polystyrene– polyisoprene–polystyrene) block copolymer film. The process utilizes reactive ion plasma to selectively modify the PS surface with amine groups to electrostatically attract negatively charged Au nanoparticles. In spite of the strong interparticle Coulombic repulsion, the deposition on PS domains is significantly high. It is observed that the deposition at the edges of the domain is particularly high, forming a percolating nanoparticle necklace. The latter may lead to interesting avenues to fabricate electronic devices.

Hyperthermic Effects Of Gold Nanorods On Tumor Cells, Terry B. Huff, Ling Tong, Matthew N. Hansen, Ji-Xin Cheng, Alexander Wei

Other Nanotechnology Publications

Plasmon-resonant gold nanorods, which have large absorption cross sections at near-infrared frequencies, are excellent candidates as multifunctional agents for image-guided therapies based on localized hyperthermia. The controlled modification of the surface chemistry of the nanorods is of critical importance, as issues of cell-specific targeting and nonspecific uptake must be addressed prior to clinical evaluation. Nanorods coated with cetyltrimethylammonium bromide (a cationic surfactant used in nanorod synthesis) are internalized within hours into KB cells by a nonspecific uptake pathway, whereas the careful removal of cetyltrimethylammonium bromide from nanorods functionalized with folate results in their accumulation on the cell surface over the …

Application Of Advanced Computational Modelling In The Comparison Of Stent Induced Coronary Flow Disturbances, Jonathan Murphy, Fergal Boyle

Conference Papers

Coronary stent implantation can improve blood flow in an artery narrowed by the build up of arterial plaque. However, the haemodynamic effect of stent placement is unclear and may influence arterial restenosis (re-blockage). In this investigation computational fluid dynamics (CFD) was used to predict the non-Newtonian three-dimensional flow field in a coronary artery following implantation of two different stents. A graphical illustration of the stented areas affected to various degrees of wall shear stress (WSS) is presented for both the Palmaz-Schatz (PS) and the Gianturco-Roubin-II (GR-II) coronary stents. The axial WSS and wall shear stress gradient (WSSG) is also presented …

Neural And Electromyographic Correlates Of Wrist Posture Control, Aaron J. Suminski, Stephen M. Rao, Kristine M. Mosier, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

In identical experiments in and out of a MR scanner, we recorded functional magnetic resonance imaging and electromyographic correlates of wrist stabilization against constant and time-varying mechanical perturbations. Positioning errors were greatest while stabilizing random torques. Wrist muscle activity lagged changes in joint angular velocity at latencies suggesting trans-cortical reflex action. Drift in stabilized hand positions gave rise to frequent, accurately directed, corrective movements, suggesting that the brain maintains separate representations of desired wrist angle for feedback control of posture and the generation of discrete corrections. Two patterns of neural activity were evident in the blood-oxygenation-level-dependent (BOLD) time series …

Multi-Degree Of Freedom Telemanipulation In An Unstructured Environment, Diego Ramirez

Theses

Two approaches to 6-degrees-of-freedom telemanipulation that will accommodate different needs and skills of potential users with congenital amputation, arthrogryposis, muscular dystrophy and cerebral palsy were developed. One method uses scalable movements (i.e. position and orientation), and the second employs isometric forces and torques without movement. The scalable position approach employs a 6-degress-of-freedom electromechanical stylus whose joint orientations are used by the controlling computer to determine the position and orientation of the robot's end effector via inverse kinematics or by one-to-one matching of the stylus joint angles with those of the manipulator. The isometric method uses the measured forces and torques …

A Dynamic Supine Stander For Subjects With Disabilities Leading To Prolonged Immobility, Luis Alberto Espina

Theses

Bone tissue needs to be exposed to loading in order to stimulate the osteogenic response of the body. Disabilities that lead to prolonged immobility will result in a decrease of the osteogenic processes and an increase in resorption of bone by osteoclast cells. This disuse modeling can lead to osteopenia, osteoporosis, and subsequent non-traumatic fractures. These disabilities are varied in nature and duration, and can include load bearing bone fracture, excessive obesity, spinal cord injury, and cerebral palsy.

The following describes the concept and design of a novel dynamic supine stander that will provide loads simulating ambulation to the lower …

A Kinematic Analysis Of Sign Language, Chemuttaai C. Koech

Theses

Signed languages develop among deaf populations and employ manual communication instead of voiced communication. Stokoe attributes classify individual signs in American Sign Language (ASL) and include handshape, hand location, movement, orientation, and facial expression. Signed and oral languages are not mutually understood, and many deaf individuals live in linguistic isolation. This research addresses computer translation between signing and speech, investigating sign duration in sentence context versus in isolation and identifying kinematic sign markers. To date, there has been little study of continuous signing kinematics; it was previously unknown if kinematic markers existed.

Kinematic data were collected from a proficient signer …

Implementation Of Stereo Correspondence Algorithms For Multi-Baseline Vision System, Navaneetha Shivram

Theses

The purpose of this study is to determine the impact of varying camera baselines on correspondence and depth estimation. As the baseline increases the resolution of depth increases but finding correspondences is very tedious. On the other hand when cameras are placed close to each other and thereby reducing the baseline distance points in the images are easily matched however depth resolution deteriorates. This problem is solved by using a multi-camera system is used in which the cameras are spaced close to each other along a straight line. Calculating the correspondence along successive camera pairs is relatively easy. These respondences …

Inverse Dynamic Modeling For Characterization Of Spasticity, Katharine Markel Swift

Theses

Spasticity affects subjects with cerebral palsy, stroke, multiple sclerosis, and traumatic brain injury. The need to develop a deeper understanding of spasticity is driven by the existing limited understanding and the lack of satisfactory interventions for this disabling phenomenon.

An inverse model is implemented to describe the motion in the pendulum knee drop test. Inverse kinematic modeling is implemented to investigate the pathophysiology of spasticity.

Using the equilibrium point hypothesis as a conceptual framework to explain disabled and non-disabled neuromuscular control, it has been demonstrated that the equilibrium point of the passive knee is dynamic and exhibits a pseudo-exponential trajectory …

Evaluation Of Stent Design Based On The Haemodynamic Effect Of Coronary Stenting, Jonathan Murphy, Fergal Boyle

Conference Papers

No abstract provided.

Positive Model Temperature And Its Effect On Stiffness And Percent Crystallinity Of Polypropylene, Mark Geil

Faculty Articles

No abstract provided.

Biomechanics Of The Rabbit Knee And Ankle: Muscle, Ligament, And Joint Contact Force Predictions, Dustin M. Grover, Andrew A. Chen, Scott J. Hazelwood

Biomedical Engineering

Mathematical models of small animals that predict in vivo forces acting on the lower extremities are critical for studies of musculoskeletal biomechanics and diseases. Rabbits are advantageous in this regard because they remodel their cortical bone similar to humans. Here, we enhance a recent mathematical model of the rabbit knee joint to include the loading behavior of individual muscles, ligaments, and joint contact at the knee and ankle during the stance phase of hopping. Geometric data from the hindlimbs of three adult New Zealand white rabbits, combined with previously reported intersegmental forces and moments, were used as inputs to the …

Volume Effects On Fatigue Life Of Equine Cortical Bone, R. F. Bigley, J. C. Gibeling, S. M. Stover, S. J. Hazelwood, D. P. Fyhrie, R. B. Martin

Biomedical Engineering

Materials, including bone, often fail due to loading in the presence of critical flaws. The relative amount, location, and interaction of these flaws within a stressed volume of material play a role in determining the failure properties of the structure. As materials are generally imperfect, larger volumes of material have higher probabilities of containing a flaw of critical size than do smaller volumes. Thus, larger volumes tend to fail at fewer cycles compared with smaller volumes when fatigue loaded to similar stress levels. A material is said to exhibit a volume effect if its failure properties are dependent on the …

Medical Rehabilitation Robotics, David Kennedy, Philip Deering, James Conlon

Conference Papers

Robotic Rehabilitation is a novel field of bio engineering combining precise mechanical design with control technology through the interaction of Medical and Engineering professionals to produce a new tool in medical rehabilitation. Paralysis is one of the common symptoms of a stroke sufferer; a medical condition causing weakness in one side of the body. It is treatable with a course of physiotherapy and Interactive Robotics can greatly accelerate this recovery. Although Robotic Rehabilitation is a relatively new technology its benefits are well recognized. The objective of this research work was to develop an interactive robot for the medical rehabilitation of …

An Investigation Of The Relationship Between Dermal Stresses And Foot Ground Stresses In Diabetic Patients, Zaid M. Hasasneh

ETD Archive

The number of people diagnosed with diabetes in the U.S. has been showing a large increase. It has more than doubled during the period of 1980 to 2002. Approximately 18 million Americans have diabetes today with more than 5.2 million undiagnosed cases. While diabetes is categorized as an endocrine system disorder, some of its known complications are associated to the science of biomechanics. Foot ulcers are caused by vascular deterioration due to diabetes, but also directly related to the natural mechanical forces and loads applied to the feet. Therefore, studying these forces, their locations, distribution and their stresses may be …

Mathematical Model Of Ethanol Metabolism In Liver, Parag Pande

ETD Archive

A lumped mathematical model of liver metabolism is presented to analyze the effect of ethanol on metabolic processes of 24 hr fasted rats. The model is developed in two parts. In the first part individual kinetic models for important regulatory steps in the liver metabolic pathways are developed and in second part transport and mass balance equations in the two well mixed domains: tissue and blood, are developed to calculate intermediate metabolite concentrations and fluxes in response to the changes in ethanol and lactate concentrations in the perfusion medium. Part of the model without ethanol metabolism has been validated and …

Studying The Interaction Of Antifreeze Proteins (Type I And Type Iii) With The Phospholipid Monolayers At Air/Water Interface, Suresh Essampally

ETD Archive

Heart transplantation is a successful therapeutic procedure for the patients with end stage heart disease. Various preservative techniques have been developed to increase the shelf life of organs, but still there can be tissue damage during cold storage. One mechanism leading to damage is disruption of cell plasma membranes as they pass through temperature induced phase transitions. The addition of antifreeze protein (AFP) or glycoprotein (AFGP) to storage solutions has been hypothesized to reduce the leakiness of lipid membranes. From studies using liposomes it has been shown that AFPs can prevent leakage through lipid membranes, although the mechanism of interaction …

Development And Modeling Of High Temperature Polymeric Heater, Maziyar Bolourchi

ETD Archive

Polymers are generally known for their excellent insulative properties. The addition of carbonaceous fillers such as carbon black and graphite within a polymer matrix can impart electrical and thermal properties making them good conductors. The resulting composites can be used in applications requiring and/or ranging from electromagnetic and radio frequency interference (EMI/RFI) shielding, electrostatic discharge (ESD) and heaters/heating elements to which metals have been the materials of choice. The advantages of using such composites include cost reduction, part consolidation, chemical resistance, lighter weight, and ability to easily design into complex three dimensional shapes via injection molding. For this work, various …

Chitosan Paste From Crawfish Shells As A Synthetic Bone Graft Material: Preparation, Characterization And Animal Study, Jerome G. Saltarrelli Jr.

Doctoral Dissertations

Bone loss associated with musculoskeletal trauma or metabolic diseases often requires bone grafts. Autograft or allograft bones are limited in supply. Therefore, development of synthetic bone graft materials is an active area of research. For several years the biomaterials group at LSUHSC-Shreveport has been investigating the use of chitosan purified from crawfish shells using a process patented by my research advisor, Dr. Debi Mukherjee.

Chitin is a polysaccharide that exists in fungi, exoskeleton of insects and outer shell of crustaceans. It is biocompatible, osteoconductive, antimicrobial, biodegradable, non-toxic, haemostatic, fungicidal, and the second most abundant natural polysaccharide on earth. Removal of …

Drug Loading And Release From Polypeptide Multilayer Nanofilms, Yang Zhong

Doctoral Dissertations

Polypeptides, linear macromolecules, are formed from amino acid residues by linkage of peptide bonds. Proteins are polypeptides too, with more complex conformations contributing to specific functionalities. Disulfide bonds are very important to maintain the structure and functions of proteins, which will form between two cysteine (Cys) residues under oxidizing circumstance.

Cys containing polypeptides are designed and synthesized by F-moc (9-Fluorenylmethyloxycarbonyl) chemistry. The number and position of Cys residues can be controlled by amino acid sequences design and following peptide synthesis, which is important to gain insights on the nature of polyelectrolyte multilayer film assembly and stability.

Both commercial and designed …

Resistance Of The Target Islet Tissue To Autoimmune Destruction Contributes To Genetic Susceptibility In Type 1 Diabetes., Natasha J. Hill, Aleksandr Stotland, Michelle Solomon, Patrick Secrest, Elizabeth Getzoff, Nora Sarvetnick

Journal Articles: Regenerative Medicine

Type 1 diabetes occurs when self-reactive T lymphocytes destroy the insulin-producing islet beta cells of the pancreas. The defects causing this disease have often been assumed to occur exclusively in the immune system. We present evidence that genetic variation at the Idd9 diabetes susceptibility locus determines the resilience of the targets of autoimmunity, the islets, to destruction. Susceptible islets exhibit hyper-responsiveness to inflammatory cytokines resulting in enhanced cell death and increased expression of the death receptor Fas. Fas upregulation in beta cells is mediated by TNFR2, and colocalization of TNFR2 with the adaptor TRAF2 in NOD beta cells is altered. …

Understanding Standing, Christopher Storey

Doctoral Dissertations

Research objectives. Psychophysical acceleration threshold is a tool for detecting deficits in dynamic postural control. Our lab has shown differences in the acceleration threshold among young adults, elderly adults, and elderly adults with diabetes. Electromyography, Semmes-Weinstein monofilaments, and hearing tests investigate the underlying physiological mechanisms for the detriments in postural control. Due to peri-sway perturbations, the motion of a person's sway affects the signal to noise ratio for perturbed stance. Since increases in sway range accompany postural instabilities, sway entrainment will allow us to investigate changes in acceleration threshold at different points in sway. The center of pressure, observed …

Noninvasive Quantification Of Fluid Mechanical Energy Losses In The Total Cavopulmonary Connection With Magnetic Resonance Phase Velocity Mapping, Anand K. Venkatachari, Sandra S. Halliburton, Randolph M. Setser, Richard D. White, George P. Chatzimavroudis

Chemical & Biomedical Engineering Faculty Publications

A major determinant of the success of surgical vascular modifications, such as the total cavopulmonary connection (TCPC), is the energetic efficiency that is assessed by calculating the mechanical energy loss of blood flow through the new connection. Currently, however, to determine the energy loss, invasive pressure measurements are necessary. Therefore, this study evaluated the feasibility of the viscous dissipation (VD) method, which has the potential to provide the energy loss without the need for invasive pressure measurements. Two experimental phantoms, a U-shaped tube and a glass TCPC, were scanned in a magnetic resonance (MR) imaging scanner and the images were …

Orthogonal Linear Regression In Roentgen Stereophotogrammetry, Patrick Atkinson, Jesse V. Benny, Brian J. Mccartin

Mechanical Engineering Publications

Rooted in aerial reconnaissance, mathematical photogrammetry has evolved into a mainstay of biomedical image processing. The present paper develops an algorithm for Roentgen stereophotogrammetry, a method of imaging musculoskeletal systems both static and dynamic, which incorporates a number of novel features employing techniques from projective geometry, orthogonal regression and least squares approximation. Theoretical and numerical evidence is presented of the efficacy of the proposed procedure.

Influence Of Van Der Waals Forces On Increasing The Strength And Toughness In Dynamic Fracture Of Nanofibre Networks: A Peridynamic Approach, Florin Bobaru Ph.D.

Department of Engineering Mechanics: Faculty Publications

The peridynamic method is used here to analyse the effect of van der Waals forces on the mechanical behaviour and strength and toughness properties of three-dimensional nanofibre networks under imposed stretch deformation. The peridynamic formulation allows for a natural inclusion of long-range forces (such as van der Waals forces) by considering all interactions as ‘long-range’. We use van der Waals interactions only between different fibres and do not need to model individual atoms. Fracture is introduced at the microstructural (peridynamic bond) level for the microelastic type bonds, while van der Waals bonds can reform at any time. We conduct statistical …

The Lynks Reader, Anne Marie Reamey

Theses and Dissertations

Many adults and children have problems reading and comprehending books, signs, written directions, etc. These same individuals have difficulty processing written materials as a result of right hemisphere interference. The Lynks Reader (DLR Co., Richmond, VA) is a commercially developed device which has been used to help individuals move from their right to their left hemisphere and to increase reading fluency and comprehension. The objective of this project was to evaluate the best way to use the various forms of the Lynks Reader. Using the device demonstrated an increase in reading fluency and comprehension by increasing the left hemisphere dominance. …

Bioelectric Effects Of Intense Nanosecond Pulses, Karl H. Schoenbach, Barbara Y. Hargrave, Ravindra P. Joshi, Juergen F. Kolb, Richard Nuccitelli, Christopher J. Osgood, Andrei G. Pakhomov, Michael W. Stacey, James R. Swanson, Jody A. White, Shu Xiao, Jue Zhang, Stephen J. Beebe, Peter F. Blackmore, E. Stephen Buescher

Bioelectrics Publications

Electrical models for biological cells predict that reducing the duration of applied electrical pulses to values below the charging time of the outer cell membrane (which is on the order of 100 ns for mammalian cells) causes a strong increase in the probability of electric field interactions with intracellular structures due to displacement currents. For electric field amplitudes exceeding MV/m, such pulses are also expected to allow access to the cell interior through conduction currents flowing through the permeabilized plasma membrane. In both cases, limiting the duration of the electrical pulses to nanoseconds ensures only nonthermal interactions of the electric …

Transfer Function Modelling: A Student-Centred Learning Approach, Aidan O'Dwyer

Conference papers

Traditionally, the modelling of real systems in engineering, using transfer functions, has been done in a mathematically intense manner. However, non-traditional learners such as mature students, part-time students and students without a conventional second-level educational background may not have strong mathematical foundations; in addition, all students increasingly expect technical work which is practical and which motivates independent learning. This paper reports on, reflects on and evaluates an innovative experiment developed by the author to estimate a transfer function model of a person’s eye-brain-hand motor response. In the experiment, carried out using a PC with data acquisition capability, the person is …