Biomedical Engineering and Bioengineering Commons^™

Electrophysiologic Studies Of Hypothalamic Adenosine-5'-Triphosphate-Sensitive Potassium Channels, Dinora Hernandez

Theses

Of particular interest in this study were the electrical phenomena involving currents from the ATP sensitive K channel in isolated hypothalamic ventromedial nucleus (VMN) neurons. These neurons may play an important role in the glucose-sensing system of the body. Rat VMN neurons were isolated. For neuronal isolation, the proteolytic enzyme pronase was used. However, pronase was too harsh. The use of papain, another proteolytic enzyme, led to better neuronal morphology. The perforated patch clamp technique was used to gain access to the cell's interior. For membrane pore formation, nystatin was used; but seal formation was difficult. Amphotericin was used instead, …

Determination Of Effects Of Stress On Polymeric Ankle-Foot Due To Weight Change: Experimental Stress Analysis, Lin Yu Wang

Theses

Ankle-Foot Orthoses (AFOs) are devices that assist patients who sustained an abnormal motion at the ankle joint of the foot due to traumatic injury and stroke, etc. The objective of this project is to determine the stress patterns in AFOs under different loading conditions such as weights and genders. Thus, the location of failure can be predicted, and a redesign process can be developed. Furthermore, those experimental results will be used to verify the results obtained from the previous Finite Element Analysis (FEA) ^[11,10]. Results from the experiment showed a significant stress change due to load change. This stress …

Using Heart Variability To Measure The Effects Of Manual Medicine On Autonomic Activity, Michael Zullow

Theses

A pilot study was performed to test the theory that manual medicine techniques known as the CV4 (compression of fourth cerebral ventricle) maneuver and a sacral hold/iliac bridge hold combination increase parasympathetic activity. Manual medicine techniques are widely practiced by Doctors of Osteopathy and Chiropractors to treat physical and mental health problems. Those who have received manual therapy have reported to experience less pain, better mobility, and a greater feeling of relaxation. To help us learn about the effects of manual therapy, autonomic activity was measured scientifically rather than subjectively in this study by monitoring respiration rate and heart rate, …

Determination And Studying Of Stress Distribution In Various Ankle-Foot Orthoses : Experimental Stress Analysis, Rong Feng

Theses

Ankle-Foot Orthosis (AFO) is prescribed to constrain and inhibit abnormal motion such as "drop foot" due to stroke. Most orthoses were hand-made by orthotists according to their own experience. However, some types of AFO were easy to fatigue (out of their functional capabilities) than others due to regular usage. In order to improve the design and usage, quantitative stress analysis of different types of orthoses is needed. The objective of this project is to obtain experimental data which will confirm the results obtained from previous Finite Element Analysis (FEA)^[1]. In addition, the experimental analysis is extended to obtain …

The Relationship Between Thermoregulatory And Haemodynamic Responses Of The Skin To Relaxation And Stress, Paul O. Nketia

Theses

The present study investigated the effects of stress and relaxation on (1) EEG coherence and (2) peripheral blood flow.

EEG coherence of two meditators in two different but adjacent rooms was measured during eyes opened, eyes closed, single meditation and group meditation. The skin temperatures of the subjects together with their room temperatures were also recorded. EEG coherence plots (Cospar) showed a spread out of the alpha band to the beta, theta and occasionally to the delta wave bands during group meditation. The area above the 0.98 coherence threshold in the alpha band was greater during group meditation than during …

Renin-Angiotensin System And Its Relationship To Arterial Pressure Regulation, Sami D. Saume

Theses

The renal system is known to participate in the natural regulation of blood pressure. A renal system model that simulates interaction responses of renal output to arterial blood pressure was developed. The major components of this model are glomerular filtration rate, tubular sodium reabsorption, the renin-angiotensin system, Aldosterone secretion, and antidiuretic hormone secretion. The model's differential equations were coded using Vissim 1.2 student version. It was found that, the renal output increased as glomerular filtration rate, Aldosterone concentration, and blood pressure increased. Conversely, increasing antidiuretic hormone concentration lead to decreased renal output.

Additionally, Angiotensin II and Aldosterone concentrations increased as …

Mechanical Evaluation Of Pedicle Screw Fixation Of The Lumbar Spine, Ding Lu

Theses

Pedicle screw fixation of the lumbar spine has been reported to increase fusion rates A biomechanical evaluation of four different pedicle screw implant systems, (AO. Rogozinski, TSRH and Wiltse). was performed to compare intrinsic device stiffness under conditions of flexion-compression and forty-five degree off-axis flexion-compression The effect on stiffness of the loosening of device members was also studied. Testing was done in load control using an electrohvdrualic testing machine. UHMWPe blocks are used to simulate the vertebra.

Assuming that stiffness is directly proportional to the probability of obtaining fusion. this study allows the ranking of the systems tested in their …

Relative Dentifrice Abrasivity On Dentin And Enamel, Laura Marchetti

Theses

The abrasive characteristics of six (6) brands of toothpastes on Enamel and Dentin material were assessed. Human teeth were sliced to expose the dentin surface and then polished using 3 μm and 0.25 μm diamond paste. The outside surface of the tooth (after slicing) was used "as is" for the enamel surface testing. The surface smoothness was evaluated prior to testing using a surface profiler and averaging four (4) to five (5) readings across the surface for each sample.

The tooth slices were then embedded into the acrylic plate surface by routing out an area with a dental drill and …

Computer Simulation Of Cerebrovascular Circulation : Assessment Of Intracranial Hemodynamics During Induction Of Anesthesia, Steven D. Wolk

Theses

The purpose of this project was to develop a computer model of cerebrovascular hemodynamics interacting with a pharmacokinetic drug model to examine the effects of various stimuli during anesthesia on cerebral blood flow and intracranial pressure.

The mathematical model of intracranial hemodynamics is a seven compartment constant volume system. A series of resistances relate blood and cerebrospinal fluid fluxes to pressure gradients between compartments. Arterial, venous, and tissue compliance are also included. Autoregulation is modeled by transmural pressure dependent arterial-arteriolar resistance. The effect of a drug (thiopental) on cerebrovascular circulation was simulated by a variable arteriolar-capillary resistance. Thiopental concentration, in …

Design Of A Mode Of Delivery For Macrobead Transplantation, Jagdip Desai

Theses

The macrobead is a form of a biohybrid artificial pancreas (BAP), which is being developed to treat type 1 diabetes. A hypothetical human transplant would require 125 rat equivalent macrobeads. For intraperitoneal transplantation a mode of delivery that allows the placement of several hundred macrobeads into a basket or pouch type device is required.

In this study, four commercially available materials were studied as possible candidates for creating a pouch. These materials are polyvinyl chloride acrylic copolymer (PVC), polyethersulfone (PES), polyvinylidenedifluoride (PVDF), and polytetrafluorethylene (PTFE). Tubular pouches of each material were designed. They then underwent in vivo biocompatibility and in-vitro …

Three-Dimensional Stress Analysis Of The Femur With Prosthetic Hip Stem Utilizing Computed Tomography Scans Of The Femur For Geometry And Material Properties, Thomas J. Lavin

Theses

Three-dimensional finite element stress analyses of the femur with prosthesis hip stem were performed for two cases, one male and one female, using ideally bonded cemented titanium prostheses. Computed tomography data files were used to derive the three-dimensional femur geometry and material properties for each cortical bone element. The maximum shear stress (4.7 MPa) in the cement was greater then the maximum tensile stress and occurred at the cement-bone interface. The tensile stresses in the cement were less then the fatigue strength of the cement. The stress patterns were quite similar for the two cases.

A data analysis program was …