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2003

Biomedical Engineering and Bioengineering

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Articles 1 - 30 of 85

Full-Text Articles in Engineering

An Analysis Of Liquid Aluminum Sulfate (Alum) Use In Broiler Production Houses To Control In-House Ammonia (Nh3) Concentrations And Naturally-Occurring Salmonella And Campylobacter; The Development Of An Nh3 Emission Factor For A Typical Tennessee Broiler House., Kenneth A. Armstrong Dec 2003

An Analysis Of Liquid Aluminum Sulfate (Alum) Use In Broiler Production Houses To Control In-House Ammonia (Nh3) Concentrations And Naturally-Occurring Salmonella And Campylobacter; The Development Of An Nh3 Emission Factor For A Typical Tennessee Broiler House., Kenneth A. Armstrong

Masters Theses

No abstract provided.


Instrumented Self-Propelled Sprayer To Determine Dynamic Boom Effects On Droplet Application Uniformity, Hong Young Jeon Dec 2003

Instrumented Self-Propelled Sprayer To Determine Dynamic Boom Effects On Droplet Application Uniformity, Hong Young Jeon

Masters Theses

A self-propelled sprayer with a 27-m boom was instrumented to measure inadvertent boom movement and acceleration during field operation to quantity application uniformity. The instrumentation system was developed to monitor boom end heights, accelerations, and sprayer longitudinal position along a track. Acceleration measures included longitudinal (x), vertical (y), and transverse (z) components at the sprayer vehicle rear, boom center, and at each boom end. A PC-based data acquisition system polled sensors at 2.5 kHz. Software-implemented, 2nd-order Butterworth band pass (0.1 to 15 Hz) filtering of raw data reduced signal noise. Y-accelerations at the boom center ranged from 1.5 …


Influence Of Isoflurane On Left Atrial Function In Dogs With Pacing-Induced Cardiomyopathy: Evaluation With Pressure-Volume Relationships, Franz Kehl, John F. Ladisa, Douglas Anthony Hettrick, Judy R. Kersten, David C. Warltier, Paul S. Pagel Dec 2003

Influence Of Isoflurane On Left Atrial Function In Dogs With Pacing-Induced Cardiomyopathy: Evaluation With Pressure-Volume Relationships, Franz Kehl, John F. Ladisa, Douglas Anthony Hettrick, Judy R. Kersten, David C. Warltier, Paul S. Pagel

Biomedical Engineering Faculty Research and Publications

Objective

The actions of volatile anesthetics on left ventricular (LV) function in normal and failing hearts have been previously evaluated, but the effects of these agents on left atrial (LA) function in the presence of LV dysfunction are unknown. The hypothesis was tested that isoflurane alters LA mechanics evaluated with pressure-volume relations.

Design

Prospective.

Setting

Laboratory.

Participants

Barbiturate-anesthetized dogs (n = 8) were instrumented for measurement of aortic, LA, and LV pressures (micromanometers), and LA volume (epicardial orthogonal sonomicrometers) after 3 weeks of rapid ventricular pacing (220 beats/min).

Interventions

LA myocardial contractility (Ees) was assessed with end-systolic pressure-volume …


The Stromal Cell-Derived Factor-1alpha/Cxcr4 Ligand-Receptor Axis Is Critical For Progenitor Survival And Migration In The Pancreas., Ayse G. Kayali, Kurt Van Gunst, Iain L. Campbell, Aleksandr Stotland, Marcie Kritzik, Guoxun Liu, Malin Flodström-Tullberg, You-Qing Zhang, Nora Sarvetnick Nov 2003

The Stromal Cell-Derived Factor-1alpha/Cxcr4 Ligand-Receptor Axis Is Critical For Progenitor Survival And Migration In The Pancreas., Ayse G. Kayali, Kurt Van Gunst, Iain L. Campbell, Aleksandr Stotland, Marcie Kritzik, Guoxun Liu, Malin Flodström-Tullberg, You-Qing Zhang, Nora Sarvetnick

Journal Articles: Regenerative Medicine

The SDF-1alpha/CXCR4 ligand/chemokine receptor pair is required for appropriate patterning during ontogeny and stimulates the growth and differentiation of critical cell types. Here, we demonstrate SDF-1alpha and CXCR4 expression in fetal pancreas. We have found that SDF-1alpha and its receptor CXCR4 are expressed in islets, also CXCR4 is expressed in and around the proliferating duct epithelium of the regenerating pancreas of the interferon (IFN) gamma-nonobese diabetic mouse. We show that SDF-1alpha stimulates the phosphorylation of Akt, mitogen-activated protein kinase, and Src in pancreatic duct cells. Furthermore, migration assays indicate a stimulatory effect of SDF-1alpha on ductal cell migration. Importantly, blocking …


Tongue Movements In Feeding And Speech, Karen M. Hiiemae, Jeffrey B. Palmer Nov 2003

Tongue Movements In Feeding And Speech, Karen M. Hiiemae, Jeffrey B. Palmer

Biomedical and Chemical Engineering - All Scholarship

The position of the tongue relative to the upper and lower jaws is regulated in part by the position of the hyoid bone, which, with the anterior and posterior suprahyoid muscles, controls the angulation and length of the floor of the mouth on which the tongue body 'rides'. The instantaneous shape of the tongue is controlled by the 'extrinsic muscles ' acting in concert with the 'intrinsic ' muscles. Recent anatomical research in non-human mammals has shown that the intrinsic muscles can best be regarded as a 'laminated segmental system ' with tightly packed layers of the 'transverse', 'longitudinal', and …


Preliminary Work On The Antibacterial Effect Of Strontium In Glass Ionomer Cements, A. Guida, Mark R. Towler, J. G. Wall, R. G. Hill, S. Eramo Oct 2003

Preliminary Work On The Antibacterial Effect Of Strontium In Glass Ionomer Cements, A. Guida, Mark R. Towler, J. G. Wall, R. G. Hill, S. Eramo

Chemical and Biochemical Engineering Faculty Research & Creative Works

The antibacterial effect of strontium in glass ionomer cements (GIC) was discussed. The glass transition temperatures were found to decrease with the increasing fluorine content consistent with the fluorine replacing bridging oxygens. However no significant correlation was found between the fluoride release and the antibacterial activity.


Interpreting Hemoglobin And Water Concentration, Oxygen Saturation, And Scattering Measured In Vivo By Near-Infrared Breast Tomography, Subhadra Srinivasan, Brian W. Pogue, Shudong Jiang, Hamid Dehghani, Christine Kogel, Sandra Soho, Jennifer J. Gibson, Tor D. Tosteson, Steven P. Poplack, Keith D. Paulsen Oct 2003

Interpreting Hemoglobin And Water Concentration, Oxygen Saturation, And Scattering Measured In Vivo By Near-Infrared Breast Tomography, Subhadra Srinivasan, Brian W. Pogue, Shudong Jiang, Hamid Dehghani, Christine Kogel, Sandra Soho, Jennifer J. Gibson, Tor D. Tosteson, Steven P. Poplack, Keith D. Paulsen

Dartmouth Scholarship

Near-infrared spectroscopic tomography was used to measure the properties of 24 mammographically normal breasts to quantify whole-breast absorption and scattering spectra and to evaluate which tissue composition characteristics can be determined from these spectra. The absorption spectrum of breast tissue allows quantification of (i) total hemoglobin concentration, (ii) hemoglobin oxygen saturation, and (iii) water concentration, whereas the scattering spectrum provides information about the size and number density of cellular components and structural matrix elements. These property data were tested for correlation to demographic information, including subject age, body mass index, breast size, and radiographic …


Development Of Standard Methods To Estimate Manure Production And Nutrient Characteristics From Dairy Cattle, T. Nennich, J. H. Harrison, D. Meyer, W. P. Weiss, A. J. Heinrichs, R. L. Kincaid, W. J. Powers, Richard K. Koelsch, P. E. Wright Oct 2003

Development Of Standard Methods To Estimate Manure Production And Nutrient Characteristics From Dairy Cattle, T. Nennich, J. H. Harrison, D. Meyer, W. P. Weiss, A. J. Heinrichs, R. L. Kincaid, W. J. Powers, Richard K. Koelsch, P. E. Wright

Department of Biological Systems Engineering: Conference Presentations and White Papers

Total collection data from many universities were pooled for statistical analyses to evaluate existing data from dairy animals and determine if one or more modifications were needed for Standard Table D384.1. Many of these studies were carried out to evaluate nutritional characteristics associated with different diets. The data collected were sufficient to evaluate total manure, total and volatile solids, and N excretion values. Some experiments had sufficient number of samples analyzed to evaluate P, K, Ca, Mg, Na, Cl, S, and micro-elements. Statistical analyses were conducted to determine if a single column value was appropriate and define the regression equations …


Proposed Beef Cattle Manure Excretion And Characteristics Standard For Asae, Galen E. Erickson, B. Auvermann, R. A. Eigenberg, L. W. Greene, Terry J. Klopfenstein, Richard K. Koelsch Oct 2003

Proposed Beef Cattle Manure Excretion And Characteristics Standard For Asae, Galen E. Erickson, B. Auvermann, R. A. Eigenberg, L. W. Greene, Terry J. Klopfenstein, Richard K. Koelsch

Department of Biological Systems Engineering: Conference Presentations and White Papers

A committee was formed consisting of both animal scientists and agricultural engineers to evaluate and update current ASAE standards. An intake minus retention model was developed to estimate nutrient excretion. This approach allows users (producers, engineers, etc.) to develop site specific information based on known variables such as protein or phosphorus content of diets and cattle performance. This approach illustrates the importance of nutrition on nutrient excretion in livestock operations. Our focus is for feedlot cattle and updates excretion of dry matter (DM or total solids), organic matter (OM or volatile solids), N, P, Ca, K, Na, Mg, S, Cu, …


Use Of Computer Spreadsheets And Paper-Based Workbooks To Teach Comprehensive Nutrient Management Planning, Charles A. Shapiro, R. L. Deloughery, Richard K. Koelsch, M. J. Kucera, Charles S. Wortmann Oct 2003

Use Of Computer Spreadsheets And Paper-Based Workbooks To Teach Comprehensive Nutrient Management Planning, Charles A. Shapiro, R. L. Deloughery, Richard K. Koelsch, M. J. Kucera, Charles S. Wortmann

Department of Biological Systems Engineering: Conference Presentations and White Papers

The objective of this program was to provide producers and ag advisors the skills needed to apply for and maintain the non-engineering components of a Nebraska permit to operate a livestock waste control facility. This includes a Comprehensive Nutrient Management Plan (CNMP). Eighty six producers and advisors participated in an intensive three-session hands-on class with a total of nine contact hours at four sites in eastern Nebraska in the spring of 2002. The workshop included lecture and participant use of spreadsheet tools to assist with performing the necessary calculations. With an average of 68 % responses per session, 58% rated …


Neural Electronic Signal Detection Fidelity And Membrane Conductance, Robert B. Szlavik Oct 2003

Neural Electronic Signal Detection Fidelity And Membrane Conductance, Robert B. Szlavik

Biomedical Engineering

Abstract of paper presented at conference.


Bme Stats Fall 2003, Department Of Biomedical Engineering, Florida International University Oct 2003

Bme Stats Fall 2003, Department Of Biomedical Engineering, Florida International University

STATS

No abstract provided.


Phosphorus Management, Bahman Eghball, J.F. Shanahan, Gary E. Varvel, John E. Gilley Oct 2003

Phosphorus Management, Bahman Eghball, J.F. Shanahan, Gary E. Varvel, John E. Gilley

Biological Systems Engineering: Papers and Publications

Soils with high levels of P can contribute to excess P in runoff and subsequently pollute the surface water. Excess P in the soil can be removed from the system by harvesting crops. The objectives of this study were to evaluate corn (Zea mays L.) P removal effects on soil P reduction, and to evaluate various corn hybrids and soybean [Glycine max (L.) Merr.] varieties for differences in grain P concentration and P removal. Soil with varying P levels as a result of annual or biennial beef cattle (Bos Taurus) feedlot manure or compost application was …


Fact Sheet #2: Do I Need A Npdes Permit For My Livestock Or Poultry Operation, Richard K. Koelsch Oct 2003

Fact Sheet #2: Do I Need A Npdes Permit For My Livestock Or Poultry Operation, Richard K. Koelsch

Department of Biological Systems Engineering: Conference Presentations and White Papers

New U.S. Environmental Protection Agency (EPA) rules that took effect April 14, 2003 indicate that animal feeding operations (AFOs) can be defined as concentrated animal feeding operations (CAFOs) and required to obtain a National Pollutant Discharge Elimination System (NPDES) permit from the EPA or a designated state permitting authority. The likelihood of an AFO being classified as a CAFO will depend, in large part, on whether that operation is considered to be large, medium, or small.


Use Of Computer Spreadsheets And Paper-Based Workbooks To Teach Comprehensive Nutrient Management Planning, Charles A. Shapiro, R. L. Deloughery, Richard K. Koelsch, M. K. Kucera, Charles S. Wortmann Oct 2003

Use Of Computer Spreadsheets And Paper-Based Workbooks To Teach Comprehensive Nutrient Management Planning, Charles A. Shapiro, R. L. Deloughery, Richard K. Koelsch, M. K. Kucera, Charles S. Wortmann

Biological Systems Engineering: Papers and Publications

The objective of this program was to provide producers and ag advisors the skills needed to apply for and maintain the non-engineering components of a Nebraska permit to operate a livestock waste control facility. This includes a Comprehensive Nutrient Management Plan (CNMP). Eighty six producers and advisors participated in an intensive three-session hands-on class with a total of nine contact hours at four sites in eastern Nebraska in the spring of 2002. The workshop included lecture and participant use of spreadsheet tools to assist with performing the necessary calculations. With an average of 68 % responses per session, 58% rated …


A Concept For Early Cancer Detection And Therapy, Ronald W. Waynant, Ilko K. Ilev, Kunal Mitra Sep 2003

A Concept For Early Cancer Detection And Therapy, Ronald W. Waynant, Ilko K. Ilev, Kunal Mitra

Biomedical Engineering and Sciences Faculty Publications

Early detection and treatment of breast cancer is least costly in terms of dollars, morbidity and mortality. With new early detection x-ray technology, tumors can be found, diagnosed and treated at a much smaller size than is currently possible. This paper proposes the development of a high resolution, high quality imaging system. It is a laser-driven x-ray system with time-gated detection that removes scattering noise in the image and produces resolution on the order of 10 μm. This higher resolution and higher image quality will enable the detection of one or two millimeter tumors hopefully detecting them before metastasis. We …


Atp-Independent Contractile Proteins From Plants, Michael Knoblauch, Gundula Noll, Torsten Müller, Dirk Prüfer, Ingrid Schneider-Hüther, Dörte Scharner, Aart Van Bel, Winfried Peters Aug 2003

Atp-Independent Contractile Proteins From Plants, Michael Knoblauch, Gundula Noll, Torsten Müller, Dirk Prüfer, Ingrid Schneider-Hüther, Dörte Scharner, Aart Van Bel, Winfried Peters

Winfried S. Peters

This paper has no abstract; this is the first paragraph. Emerging technologies are creating increasing interest in smart materials that may serve as actuators in micro- and nanodevices. Mechanically active polymers currently studied include a variety of materials. ATP-driven motor proteins, the actuators of living cells, possess promising characteristics, but their dependence on strictly defined chemical environments can be disadvantagous. Natural proteins that deform reversibly by entropic mechanisms might serve as models for artificial contractile polypeptides with useful functionality, but they are rare. Protein bodies from sieve elements of higher plants provide a novel example. sieve elements form microfluidics systems …


Study Of Baroreceptor Sensitivity Index In Chronic Fatigue Syndrome, Diane L. Donnelly Aug 2003

Study Of Baroreceptor Sensitivity Index In Chronic Fatigue Syndrome, Diane L. Donnelly

Theses

Although numerous studies evaluate baroreflex response as part of their research protocol, only one was identified as having evaluated continuous baroreceptor response as part of a 70° head-up tilt. It was done by Youde et al. [28] and was limited in that it evaluated only sequences of three beats for lag 0. The limitations of the Youde study [28] are not present in this thesis.

The data for this thesis came from a 70° head-up tilt study performed on chronic fatigue syndrome subjects by LaManca et al. [3] at the East Orange VA Medical Center. Baroreflex was not evaluated as …


The Influence Of Exercise On Oxygen Uptake In Mild Hypertension, Matthew Joseph Herban Aug 2003

The Influence Of Exercise On Oxygen Uptake In Mild Hypertension, Matthew Joseph Herban

Theses

The amount of oxygen used by muscle cells increase with exercise. The two body systems that influence the amount of oxygen delivered are the cardiovascular system and the pulmonary system. Two groups of patients were studied, those that were mildly hypertensive (but are not taking prescription medication for hypertension) and the control or normal group. The two groups exercised on a bicycle ergometer. Work rate was increased in steps (multiples of thirty watts) until anaerobic threshold (as measured by an ear oximeter) was reached. Heart rate, blood pressure, oxygen uptake and carbon dioxide production were measured during exercise. Their data …


A Biologically Inspired Joint Model Using Engineering Methods To Enhance Understanding Of Muscle Activity, Richard Paradiso Aug 2003

A Biologically Inspired Joint Model Using Engineering Methods To Enhance Understanding Of Muscle Activity, Richard Paradiso

Theses

Compliant actuators and control methods have been known to exhibit similarities in human musculoskeletal systems. In order to better understand and improve the effects of force optimization under closed- loop conditions, a physical joint model was constructed with an agonist and an antagonist muscle operating under linear control. Utilizing LabVIEW software, compliant McKibben air muscles and Merlin stretch sensors, the author was able to incorporate a Bang-Bang controller and propose the inclusion of pulse width modulation (PWM) as well as a Proportional-Integral-Derivative (PD) controller to study the reflex loops under various levels of feedback sensitivity. The feedback mechanism, similar to …


Characteristics Of Phototrophic And Non-Phototrophic Lagoons For Swine Manure, Tongtong Chen, Dennis D. Schulte, Richard K. Koelsch, Anne M. Parkhurst Aug 2003

Characteristics Of Phototrophic And Non-Phototrophic Lagoons For Swine Manure, Tongtong Chen, Dennis D. Schulte, Richard K. Koelsch, Anne M. Parkhurst

Biological Systems Engineering: Papers and Publications

Odors are a major result of inadequately sized and mismanaged anaerobic lagoons. However, purple or pink colored lagoons, indicating the presence of phototrophic purple bacteria, are less likely to be an odor nuisance than are non–purple lagoons. Eight swine lagoons were studied to quantify critical parameters thought to allow purple lagoons to be a more reliable odor control alternative. Bacteriochlorophyll a (Bchl a), which indirectly measures the abundance of phototrophic bacteria, was greater in purple lagoons than in non–purple lagoons (P = 0.01). Oxidation–reduction potential (ORP) was less negative for purple lagoons than for non–purple lagoons in both spring …


A Distributed Control System For Priority-Based Site-Specific Irrigation, Fabio Rodrigues De Miranda Aug 2003

A Distributed Control System For Priority-Based Site-Specific Irrigation, Fabio Rodrigues De Miranda

Doctoral Dissertations

Site-specific irrigation enables maximizing yields and water use efficiency for fields with variation in soil water availability. Distributed control for fixed irrigated systems, with controllers close to the sensors and actuators in the field, is easier to install and maintain, and less susceptible to damage by lightning strikes compared to centralized control, but is only economically viable with affordable, low-power controllers. A low cost, solar-powered, feedback irrigation controller for distributed control of fixed irrigation systems was developed and tested. The system used soil water potential measurements to control the amount of water applied to each specific zone of a field. …


Delineation Of Management Units For Site-Specific Irrigation.”, Carlos Wagner Oliveira Aug 2003

Delineation Of Management Units For Site-Specific Irrigation.”, Carlos Wagner Oliveira

Doctoral Dissertations

Variability of soil properties in many fields is too great for a whole field to be effectively managed with a uniform application of irrigation water. Consequently, a decision must be made for irrigation management about which areas in the field should be treated differently or grouped. A decision-making framework was developed to determine whether site-specific irrigation management would be cost effective for selected fields. The framework is designed to find the best field layout in terms of water management, and tests the hypothesis that there is a particular field management layout that maximizes net return. As part of the framework, …


Interpolation Of Spatial Surfaces And Inferring Subsurface Transitions Using Electrical Conductivity, Robert Claborne Wilson Aug 2003

Interpolation Of Spatial Surfaces And Inferring Subsurface Transitions Using Electrical Conductivity, Robert Claborne Wilson

Masters Theses

Precision agriculture techniques are becoming more popular within the agriculture community as producers demand more return from an ever-decreasing amount of farmland. Increased environmental regulations are forcing farmers to reduce the input of fertilizers and agrochemicals on their crops. Innovative techniques in precision agriculture are enhancing traditional decision-making processes by offering multiple layers of data for a production field. It is difficult to determine the complex interactions that exist between factors affecting crop growth and the resultant management decisions. Strategies in precision agriculture attempt to modify customary practices in order to address the known variability of field conditions. This case …


Local Applications Of The National Livestock And Poultry Environmental Stewardship Curriculum, Diane Huntrods, Richard K. Koelsch, Frank Humenik Jul 2003

Local Applications Of The National Livestock And Poultry Environmental Stewardship Curriculum, Diane Huntrods, Richard K. Koelsch, Frank Humenik

Department of Biological Systems Engineering: Conference Presentations and White Papers

This paper introduces the LPES curriculum project, summarizing the curriculum development process, the final curriculum materials, and the outreach activities. Following an overview of the LPES Curriculum Impact Survey, the authors will present representative examples of uses and modifications made of the LPES curriculum as it is used with targeted audiences. This model for utilizing national expertise to address state and local educational needs may have benefit in other extension education programs as land grant university resources decrease. The paper concludes with a discussion of lessons learned from this national extension education curriculum development effort.


A Computational Method For Internal Radiation Dosimetry At The Voxel Level, Swapna Chigurupati Jul 2003

A Computational Method For Internal Radiation Dosimetry At The Voxel Level, Swapna Chigurupati

FIU Electronic Theses and Dissertations

The current development of hybrid SPECT/CT and PET/CT systems allows not only accurate attenuation correction of images, but also provide an anatomical frame for the 3D spatial representation of the dose distribution. The main goal of this thesis project was to develop computational algorithms for calculation of the 3D dose distribution delivered by internal emitters based on the images and information provided by new hybrid SPECT/CT and PET/CT systems. Although many experimental problems exist in patient-specific dosimetry, current drawback is the lack of radionuclide voxel S values for the set of all possible combinations of cubical and non-cubical pixel edges …


Accuracy Of Activity Quantitation Of F-18 Fluorodeoxyglucose (Fdg) Positron Emission Tomography (Pet) Imaging Using Simulated Malignant Tumors, Madhu Durai Jul 2003

Accuracy Of Activity Quantitation Of F-18 Fluorodeoxyglucose (Fdg) Positron Emission Tomography (Pet) Imaging Using Simulated Malignant Tumors, Madhu Durai

FIU Electronic Theses and Dissertations

This thesis involves a procedure, which calculated and compared the sum of all the pixel counts, threshold pixel counts sum of a 3D PET image and mean and maximum pixel count of one single transaxial slice (2D) of simulated tumors for a chosen region of interest (ROI). A calibration factor was multiplied by the sum of the pixel counts, threshold pixel counts sum of all the transaxial slices, and the mean, and maximum pixel counts of one single transaxial slice in an ROI to calculate for the activity of the tumor. This activity calculated was compared with the real activity …


A Dosimetry And Radiobiological Model For Intravascular Brachytherapy Treatment Planning With Radioisotope Emitting Stents, Maria Alejandra Caceres Jul 2003

A Dosimetry And Radiobiological Model For Intravascular Brachytherapy Treatment Planning With Radioisotope Emitting Stents, Maria Alejandra Caceres

FIU Electronic Theses and Dissertations

The aim of this study was to develop a practical, versatile and fast dosimetry and radiobiological model for calculation of the 3D dose distribution and radiobiological effectiveness of radioactive stents. The algorithm was written in Matlab 6.5 programming language and is based on the dose point kernel convolution. The dosimetry and radiobiological model was applied for evaluation of the 3D dose distribution of 32P, 90Y, 188Re and 177Lu stents. Of the four, 32P delivers the highest dose, while 90Y, 188Re and 177Lu require high levels of activity to deliver a significant therapeutic …


Short Pulse Laser Propagation Through Tissues, Champak Das, Ashish Trivedi, Kunal Mitra, Tuan Vo-Dinh Jul 2003

Short Pulse Laser Propagation Through Tissues, Champak Das, Ashish Trivedi, Kunal Mitra, Tuan Vo-Dinh

Biomedical Engineering and Sciences Faculty Publications

An experimental and numerical study is performed to analyze short pulse laser propagation through tissue phantoms without and with inhomogeneities/tumors imbedded in it. Short pulse laser probing techniques has distinct advantages over conventional very large pulse width or cw lasers primarily due to the additional information conveyed about the tissue interior by the temporal variation of the observed signal. Both the scattered temporal transmitted and reflected optical signals are measured experimentally using a streak camera for samples irradiated with a short pulse laser source. Parametric study involving different scattering and absorption coefficients of tissue phantoms and inhomogeneities as well as …


Static And Dynamic Mechanical Testing Of A Polymer With Potential Use As Heart Valve Material, Andres Felipe Aguirre Jul 2003

Static And Dynamic Mechanical Testing Of A Polymer With Potential Use As Heart Valve Material, Andres Felipe Aguirre

FIU Electronic Theses and Dissertations

Synthetic tri-leaflet heart valves generally fail in the long-term use (more than 10 years). Tearing and calcification of the leaflets usually cause failure of these valves as a consequence of high tensile and bending stresses borne on the material. The primary purpose of this study was to explore the possibilities of a new polymer composite to be used as synthetic tri-leaflet heart valve material. This composite was comprised of polystyrene-polyisobutylene-polystyrene (Quatromer), a proprietary polymer, embedded with continuous polypropylene (PP) fibers. Quatromer had been found to be less likely to degrade in vivo than polyurethane. Moreover, it was postulated that a …