Engineering Commons^™

Pulmonary Arterial Morphometry From Microfocal X-Ray Computed Tomography, Kelly L. Karau, Robert C. Molthen, Anita H. Dhyani, Steven Thomas Haworth, Christopher C. Hanger, David L. Roerig, Roger H. Johnson, Christopher A. Dawson

Biomedical Engineering Faculty Research and Publications

The objective of this study was to develop an X-ray computed tomographic method for pulmonary arterial morphometry. The lungs were removed from a rat, and the pulmonary arterial tree was filled with perfluorooctyl bromide to enhance X-ray absorbance. At each of four pulmonary arterial pressures (30, 21, 12, and 5.4 mmHg), the lungs were rotated within the cone of the X-ray beam that was projected from a microfocal X-ray source onto an image intensifier, and 360 images were obtained at 1° increments. The three-dimensional image volumes were reconstructed with isotropic resolution with the use of a cone beam reconstruction algorithm. …

Will Voluntary And Educational Programs Meet Environmental Objectives? Evidence From A Survey Of New York Dairy Farms, Gregory L. Poe, Nelson L. Bills, B. C. Bellows, Patricia Crosscombe, Richard K. Koelsch, Michael J. Kreher, Peter Wright

Biological Systems Engineering: Papers and Publications

This paper presents the results from a survey of New York dairy farms that links manure management practices and farmer willingness to participate in voluntary environmental programs, focusing on those operations that are not automatically designated as Concentrated Animal Feeding Operations. A wide divergence is found between actual and recommended manure management practices on individual dairy farms (high), the apparent ability of farms to divert financial resources to environmental practices (mixed), and the willingness to participate in voluntary programs at various annual costs per cow (low). These findings have policy implications for the USDA/USEPA National Strategy for Animal Feeding Operations.

Computed Tomography To Assess Pulmonary Injury Associated With Concurrent Chemo-Radiotherapy For Inoperable Non-Small Cell Lung Cancer, Galit Aviram, Edward Yu, Patricia Tai, Michael Lefcoe

Edward Yu

OBJECTIVE: To characterize serial computed tomography (CT) findings of pulmonary injury after a uniform regimen of concurrent chemo-radiotherapy in inoperable non-small cell lung cancer, and to compare the radiation-induced lung toxicity with other concurrent chemo-radiation regimens. METHODS: Twenty-four patients with advanced non-small cell lung cancer received 2 induction cycles of cisplatin and vinblastine, followed by 2 further cycles of cisplatin and vinblastine, concurrent with 60 Gy radiation at 2 Gy per fraction. Radiation-induced lung injury in the acute and chronic phases was assessed by serial CT scans and compared with preradiation baseline scans. Acute radiation pneumonitis was evaluated using the …

Bme Stats Fall 2001, Department Of Biomedical Engineering, Florida International University

STATS

No abstract provided.

Automated Myocardial Infarction Diagnosis From Ecg, Chen Zhou

Doctoral Dissertations

In the present dissertation, an automated neural network-based ECG diagnosing system was designed to detect the presence of myocardial infarction based on the hypothesis that an artificial neural network-based ECG interpretation system may improve the clinical myocardial infarction. 137 patients were included. Among them 122 had myocardial infarction, but the remaining 15 were normal. The sensitivity and the specificity of present system were 92.2% and 50.7% respectively. The sensitivity was consistent with relevant research. The relatively low specificity results from the rippling of the low pass filtering. We can conclude that neural network-based system is a promising aid for the …

High Temperature Fatigue Crack Growth Behavior Of Ti-6al-4v, N. K. Arakere, Tarun Goswami, J. Krohn, N. Ramachandran

Biomedical, Industrial & Human Factors Engineering Faculty Publications

Experimental evaluation of high temperature, Fatigue Crack Growth Rate (FCGR) data for Ti-6A1-4V, a titanium alloy, is presented. The FCGR data were measured at room temperature, 175, 230, 290 and 345°C using the Direct Current Potential Difference (DCPD) technique. Compact Tension (CT) specimens were used in the program and crack growth rates (da/dN) vs. Mode I stress intensity factor ranges (ΔΚ) were plotted as a function of temperature. A temperature rise from 175 to 345°C did not cause a substantial increase in crack growth rates within the Stage II region where a linear relationship describes the behavior. Fonnation of secondary …

The Effect Of Low Levels Of Zirconia Addition On The Mechanical Properties Of Hydroxyapatite, Mark R. Towler, I. R. Gibson

Chemical and Biochemical Engineering Faculty Research & Creative Works

The effect of low levels of zirconia addition on the mechanical properties of hydroxyapatite was analyzed. Optimum amount of zirconia required to prevent decomposition of hydroxyapatite during sintering was determined. The particle size, morphology and surface area were measured and calcium to phosphorus ratio and trace element impurity content were determined by x-ray fluorescence. Low level addition of zirconia resulted in composites with better mechanical properties and minimum levels of decomposition.

Nutrients In Runoff Following The Application Of Swine Manure To Interrill Areas, John E. Gilley, Bahman Eghball, B. J. Weinhold, Phillip S. Miller

Biological Systems Engineering: Papers and Publications

The P content of swine manure can be reduced through the addition of feed supplements or the use of selected corn hybrids. This study was conducted to compare interrill runoff losses of P and N from three soils following the application of swine manure obtained from selected diets. The soils used in this investigation included a Hersh sandy loam, Pierre silty clay, and Sharpsburg silt loam. Simulated rainfall was applied during both initial and wet runs to a soil pan on which swine manure produced from low phytate corn (LPC), phytase added to the diet (PHY), or a traditional corn …

Initial Hertzian Characteristics Of The Human Tooth As A Damage Tolerant Bio-Ceramic/Bio-Composite Bi-Layer, Ivory Camille Kilpatrick

Theses

The objective of this thesis was to investigate the Hertzian Contact response of human teeth and how the response behavior is related to that of model ceramic bi-layers (high modulus brittle ceramics on compliant substrates). Hertzian Contact is a blunt indentation method, which uses a hard spherical indenter to apply a normal compressive load. Clinical variables of masticatory (occlusal) force and cuspal curvature identify closely with the independent Hertzian variables of contact load and sphere radius [1]. This method offers insight into the role of microstructure and microstructure- sensitive mechanical properties. It was hypothesized that tooth damage modes and patterns …

Encoding And Storage Components Of Verbal Working Memory As Revealed By A Factorial Design, An Fmri Study, Jason Steffener

Theses

In this fMRI study, the contributions of frontal and posterior brain regions to verbal working memory were investigated. A two-factor design with low and high memory load (2 and 5 letters) and short and long delay (4 and 12 secs.) as factors were used. Based on reports in the literature, we expect activity in the following frontal and parietal brain regions of interest (ROIs): Brodmann areas (BA) 6, 9, 46, 44, 45, 7 and 40. The analysis of collected flvM data involved image processing and statistical analysis methods including realignment, spatial normalization, spatial smoothing, temporal filtering, intensity normalization, statistical tests, …

The Crystallisation Of Glasses From The Ternary Caf2-Caal2si2o8-P2 O5 System, A. Clifford, R. G. Hill, Mark R. Towler, D. J. Wood

Chemical and Biochemical Engineering Faculty Research & Creative Works

A study of glasses from the ternary system CaF₂-CaAl₂Si₂O₈-P₂O₅ has been carried out. It has been shown that glasses with low phosphorus contents and high fluorite contents crystallise to fluorite. Fluorine reduces the glass transition temperature and is also required for the formation of fluorapatite (FAP). In the absence of fluorine in the glass no apatite phase is formed. Bulk nucleation of FAP is favoured for glasses with Ca:P ratios close to the apatite stoichiometry of 1.67 and with low crosslink densities. Thermal gravimetric analysis showed significant weight losses …

Learning To Move Amid Uncertainty, Robert A. Scheidt, Jonathan B. Dingwell, Ferdinando A. Mussa-Ivaldi

Biomedical Engineering Faculty Research and Publications

We studied how subjects learned to make movements against unpredictable perturbations. Twelve healthy human subjects made goal-directed reaching movements in the horizontal plane while holding the handle of a two-joint robotic manipulator. The robot generated viscous force fields that perturbed the limb perpendicular to the desired direction of movement. The amplitude (but not the direction) of the viscous field varied randomly from trial to trial. Systems identification techniques were employed to characterize how subjects adapted to these random perturbations. Subject performance was quantified primarily using the peak deviation from a straight-line hand path. Subjects adapted their arm movements to the …

Role Of Nitric Oxide As A Modulator Of Platelet Dense Granule Release, Clifton Ford Frilot Ii

Doctoral Dissertations

Nitric oxide (NO) has been shown to suppress platelet activation, induce vasodilation, inhibit smooth muscle cell proliferation, and act against infection. Activated platelets generally have opposite effects from these. They secrete platelet-derived growth factor (PDGF), which stimulates smooth muscle growth, serotonin, which is a platelet agonist, and a number of agents that promote further platelet aggregation. However, activated platelets also produce NO through the enzymatic functions of the constitutive form of nitric oxide synthase (NOS). The primary functions of this capability are not yet completely understood. Due to its low molecular weight and high diffusivity, NO is quickly transported from …

Use Of Short-Pulse Laser For Optical Tomography Of Tissues, Kunal Mitra, Tuan Vo-Dinh

Biomedical Engineering and Sciences Faculty Publications

This paper analyzes the short pulse laser propagation through tissues for development of a time-resolved optical tomography system for detection of tumors and inhomogeneities in tissues. Traditional method for analyzing optical transport in tissues is the parabolic or diffusion approximation in which the energy flux is assumed proportional to the fluence (intensity averaged over all solid angles) gradients. The inherent drawback in this model is that it predicts infinite speed of propagation of the optical signal. In this paper accurate hyperbolic or wave nature of transient radiative transfer formulation is used to overcome such drawbacks. The transmitted and reflected intensity …

A Preliminary Comparison Of The Mechanical Properties Of Chemically Cured And Ultrasonically Cured Glass Ionomer Cements, Using Nano-Indentation Techniques, Mark R. Towler, A. J. Bushby, R. W. Billington, R. G. Hill

Chemical and Biochemical Engineering Faculty Research & Creative Works

There is a requirement for a dental cement with properties comparable or superior to conventional glass ionomer cements (GICs) but with the command set properties of the resin modified GICs. The objective of this work was to show that the application of ultrasound to conventional Fuji IX commercial glass ionomer cement imparts a command set, whilst improving the short-term surface mechanical properties. Nano-indentation techniques were employed to highlight the improvements in hardness and creep resistance imparted to the cement through the application of ultrasound. The instant set imparted by the application of ultrasound provides improved surface hardness and creep, particularly …

Partial Characterization Of Extruded Collagen Tubes With Varied Material Deposition And Orientation Based On Rotation Rate And Linear Draw Speed, Richard Peter Hoppe

Theses

This study established protocols for extrusion of collagen tubes from an extruder made by the ZOKO Corporation of Czechoslovakia. Using a viscous collagen base material, collagen tubes can be formed with changes in rotation rates from 0 rpm to 260 rpm and linear draw speeds from 383 mm/min to 1270 mm/min with a constant extrusion rate of 50 cm²/min. These tubes, with further research and treatment, can be used for various medical applications including vascular implants and nerve conduits.

Post-extrusion, chemical crosslinking of the collagen increased the cohesiveness and mechanical integrity of the tubes. Microscopic photographs confirmed higher …

Waveguide Delivery Of X Rays For Minimally Invasive Tumor Therapy, Ronald W. Waynant, Ilko K. Ilev, Kunal Mitra

Biomedical Engineering and Sciences Faculty Publications

We are studying the potential use of x-rays, which are collected by non-imaging optics and delivered through stereotactically guided needles by hollow waveguides, for irradiation of tumors. X-rays have greater transparency in tissue than most longer optical wavelengths and may provide a more uniform dose to a tumor without harming normal tissue. Dosimetry is the key to minimal damage. We are investigating the use of fiber optics, tipped with calibrated scintillators and strategically located near the tumor, to measure the delivered dose. We are testing this procedure by using a 3 ns, variable accelerator voltage Fexitron 706 to produce approximately …

Studies On The Formation Of Dna-Cationic Lipid Composite Films And Dna Hybridization In The Composites, Murali Sastry, Vidya Ramakrishnan, Mrunalini Pattarkine, Krishna N. Ganesh

Faculty Works

The formation of composite films of double-stranded DNA and cationic lipid molecules (octadecylamine, ODA) and the hybridization of complementary single-stranded DNA molecules in such composite films are demonstrated. The immobilization of DNA is accomplished by simple immersion of a thermally evaporated ODA film in the DNA solution at close to physiological pH. The entrapment of the DNA molecules in the cationic lipid film is dominated by attractive electrostatic interaction between the negatively charged phosphate backbone of the DNA molecules and the protonated amine molecules in the thermally evaporated film and has been quantified using quartz crystal microgravimetry (QCM). Fluorescence studies …

Alterations In P53 And E2f-1 Function Common To Immortalized Chicken Embryo Fibroblasts, Sakthikumar Ambady, Hyunggee Kim, Seungkwon You, In-Jeong Kim, Linda Foster, James Farris, F Able Ponce Leon, Douglas Foster

Sakthikumar Ambady

A number of non-virally and non-chemically immortalized chicken embryo fibroblast (CEF) cells have been established recently in continuous cell culture. All immortal CEF cells tested showed common genetic alterations in the expression patterns of p53 and E2F-1 mRNA and protein which were down- and up-regulated, respectively. The biological effects of differentially regulated p53 and E2F-1 were determined by reporter gene transcriptional activity assays, DNA binding assays, and Northern blot analysis of the expression patterns of down-stream genes. In addition, expression of most of the cyclin genes was up-regulated in immortal CEF cells, which may be associated with the rapid cell …

Generation Of Oxygen Microbubbles In A Microchannel With Crosscurrent Liquid Flow, Sung Sam Kim

Doctoral Dissertations

An alternative way of blood oxygenation is proposed by introducing small bubbles directly into the blood stream. To be used for blood oxygenation, the bubble should be small enough to pass through the capillary beds. To explore the feasibility of producing small bubbles, bubble formation phenomena in a crosscurrent liquid flow in a silicon microchannel were studied. Small orifices with 4 μm, 4.2 μm, and 6.6 μm hydraulic diameter were machined in a direction perpendicular to a trapezoidal channel that has a hydraulic diameter of 42 micrometers. These orifices were connected to three different chambers of 2.5 × 10−7 cm3, …

Evaluation Of 135- And 150-Degree Sliding Hip Screws, Kelly Blayne Crittenden

Doctoral Dissertations

Sliding hip screws are routinely used to repair Garden III femoral neck factures. This research seeks to better understand the influence of the hip screw angle on the performance of the fixation. The mechanics of fractured femurs repaired with 135- and 150-degree sliding fixation devices are explored using experimental, finite element, and analytical modeling. The experimental study involves testing of both intact and fixated femurs; the finite element work centers on two-dimensional models of intact and fixated femurs; and the analytical modeling explores the forces, moments and stresses in the fixation. The analytical model predicts that the screw will serve …

A Mechanistic Model For Internal Bone Remodeling Exhibits Different Dynamic Responses In Disuse And Overload, Scott J. Hazelwood, R. Bruce Martin, Mark M. Rashid, Juan J. Rodrigo

Biomedical Engineering

Bone is a dynamic tissue which, through the process of bone remodeling in the mature skeleton, renews itself during normal function and adapts to mechanical loads. It is, therefore, important to understand the effect of remodeling on the mechanical function of bone, as well as the effect of the inherent time lag in the remodeling process. In this study, we develop a constitutive model for bone remodeling which includes a number of relevant mechanical and biological processes and use this model to address differences in the remodeling behavior as a volume element of bone is placed in disuse or overload. …

In Vivo Flow Dynamics Of The Total Cavopulmonary Connection From Three-Dimensional Multislice Magnetic Resonance Imaging, Shiva Sharma, Ann E. Ensley, Katherine Hopkins, George P. Chatzimavroudis, Timothy M. Healy, Vincent K.H. Tam, Kirk R. Kanter, Ajit P. Yoganathan

Chemical & Biomedical Engineering Faculty Publications

Background. The total cavopulmonary connection (TCPC) design continues to be refined on the basis of flow analysis at the connection site. These refinements are of importance for myocardial energy conservation in the univentricular supported circulation. In vivo magnetic resonance phase contrast imaging provides semiquantitative flow visualization information. The purpose of this study was to understand the in vivo TCPC flow characteristics obtained by magnetic resonance phase contrast imaging and compare the results with our previous in vitro TCPC flow experiments in an effort to further refine TCPC surgical design.

Methods. Twelve patients with TCPC underwent sedated three-dimensional, multislice …

Circumferential Creep Of Human Cortical Bone Suggests Threshold For Press - Fit Stems, C. U. Brown, V. L. Kish, Timothy L. Norman, T. A. Gruen, J. D. Blaha

Engineering and Computer Science Faculty Presentations

No abstract provided.

Damage Evolution And Fracture Behavior Of Human Compact Bone Specimens In 3 - Point Bending, G. P. Parsamian, V. L. Kish, Timothy L. Norman

Engineering and Computer Science Faculty Presentations

No abstract provided.

In - Vivo Diffuse Damage In Human Cortical Bone Does Not Compromise Bone Toughness, Timothy L. Norman, G. P. Parsamian, C. Coleman

Engineering and Computer Science Faculty Presentations

No abstract provided.

Michaelis–Menten Kinetics For Enzymatic Depolymerization Of A Linear Polyester Synthesized From Z-Protected Glutamic Acid, R M. Tadros, Hossein Noureddini, Delmar C. Timm

Papers in Biomaterials

A biodegradable polyester resin was polymerized from N-benzyloxycarbonyl- L -glutamic acid and ethylene glycol. Rhizopus delemar lipase was used as a biocatalyst for the rupture of ester bonds during the hydrolysis studies. Depoly-merization was observed to followa Michaelis–Menten mechanism, with the maximumrate of monomer formation dP/dtmax = 1.12 x 10-8 mol/s and the rate constant Km x 2.03 x 10-4 mol. Subject to initial conditions described by the most probable distribution and Michaelis–Menten–type depolymerization rate expressions, population density distribu-tion dynamics of the polymeric molecules that formed the resin were explicitly described using a deterministic ap-proach.

Pulmonary Arterial Remodeling Revealed By Microfocal X-Ray Tomography, Kelly L. Karau, Robert C. Molthen, Anita H. Dhyani, Steven Thomas Haworth, Christopher A. Dawson

Biomedical Engineering Faculty Research and Publications

Animal models and micro-CT imaging are useful for understanding the functional consequences of, and identifying the genes involved in, the remodeling of vascular structures that accompanies pulmonary vascular disease. Using a micro-CT scanner to image contrast-enhanced arteries in excised lungs from fawn hooded rats (a strain genetically susceptible to hypoxia induced pulmonary hypertension), we found that portions of the pulmonary arterial tree downstream from a given diameter were morphometrically indistinguishable. This 'self-consistency' property provided a means for summarizing the pulmonary arterial tree architecture and mechanical properties using a parameter vector obtained from measurements of the contiguous set of vessel segments …

Semiautomated Skeletonization Of The Pulmonary Arterial Tree In Micro-Ct Images, Christopher C. Hanger, Steven Thomas Haworth, Robert C. Molthen, Christopher A. Dawson

Biomedical Engineering Faculty Research and Publications

We present a simple and robust approach that utilizes planar images at different angular rotations combined with unfiltered back-projection to locate the central axes of the pulmonary arterial tree. Three-dimensional points are selected interactively by the user. The computer calculates a sub- volume unfiltered back-projection orthogonal to the vector connecting the two points and centered on the first point. Because more x-rays are absorbed at the thickest portion of the vessel, in the unfiltered back-projection, the darkest pixel is assumed to be the center of the vessel. The computer replaces this point with the newly computer-calculated point. A second back-projection …

An Automated Approach For Comparative Analysis Of Interval And Heart Rate Variability, Taral Oza

Theses

Cardiovascular disease is the primary cause of death in the adult population. Half of these cardiac deaths occur as sudden death. Some of the parameters from the surface ECG recording (a noninvasive technique) carry important information and have special significance in research, as they are good indicators of diseases leading to heart attacks, sudden cardiac death and other similar cardiac problems. Measurement of QT interval variability and heart rate variability are two such parameters, which has received much attention of researchers.

An algorithm has been developed to measure and compare the two significant parameters, the QT interval variability and the …