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Biomedical engineering

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Full-Text Articles in Biomedical Engineering and Bioengineering

Development Of A Coupled Model Of The Cardiorespiratory And Thermoregulatory Systems , Dawn Denise Downey Jan 1998

Development Of A Coupled Model Of The Cardiorespiratory And Thermoregulatory Systems , Dawn Denise Downey

Retrospective Theses and Dissertations

A model of the human body which integrates the variables involved in temperature regulation and blood gas transport within the cardiovascular and respiratory systems is presented in this dissertation. It expands upon previous work developed by the author to model the competition between skin and muscles when both require increased blood flows during exercise and/or heat stress. First, a detailed study of the control relations used to predict skin blood flow was undertaken. Four other control relations employed in the model were also examined and modified as indicated by empirical results found in literature;Several important cases were then ...


A Quantitative Estimation Of Regulation And Transport Limitations In The Human Cardiopulmonary System , Sharmista Chatterjee Jan 1997

A Quantitative Estimation Of Regulation And Transport Limitations In The Human Cardiopulmonary System , Sharmista Chatterjee

Retrospective Theses and Dissertations

The object of this dissertation is to quantitatively describe the regulation of some of the exchange processes within the human body. Conceptually this dissertation is divided into two sections. In the first section a macroscopic view was adopted to describe the overall regulation of the cardiovascular and respiratory systems. These overall system models were used as heuristic tools to gain an understanding of physiological behavior in micro-gravity. In the second section, a microscopic view was used to estimate the role played by the surfactant system of the lung in regulating the transfer of fluid across the pulmonary-capillary wall;The basis ...


Computer Simulation Of Coronary Blood Flow , Brian Christopher Frake Jan 1995

Computer Simulation Of Coronary Blood Flow , Brian Christopher Frake

Retrospective Theses and Dissertations

A computer model to simulate coronary fluid dynamics has been developed which can give some insight into the role of hemodynamics in health and disease. Although this study focuses mainly on coronary blood flow, the complete model consists of all major branches of the systemic circulation as well as the left epicardial coronary circulation;The flow equations are obtained by integrating the one-dimensional continuity and momentum equations over the cross-section of the artery to give a relationship between the primary variables of interest, the pressure and flowrate. An arctangent model was used as a constitutive equation to describe the pressure-area ...


An Investigation Into The Role Of Arterial Wall Vibration In The Pathogenesis Of Atherosclerosis , Becky Bellatti Bittle Jan 1994

An Investigation Into The Role Of Arterial Wall Vibration In The Pathogenesis Of Atherosclerosis , Becky Bellatti Bittle

Retrospective Theses and Dissertations

Fifty percent of all the deaths in the Western world can be attributed to diseases of the cardiovascular system. A major player amongst these diseases is atherosclerosis. Atherosclerosis is the localized thickening of the arterial wall and is primarily due to the proliferation of fibrous tissue and smooth muscle cells in conjunction with the deposition of lipids within the wall. The hypothesis investigated was that high frequency, low amplitude vibratory environments similar to those found in regions of disturbed flow, which are coincident with intimal thickenings, the earliest stage of atherosclerosis, do elicit a proliferative response in vascular smooth muscle ...


Evaluation Of A Direct Systolic Cardiac Augmentation Device On A Canine Heart During Global Postischemic Dysfunction , Raymond Kenneth Kudej Jan 1994

Evaluation Of A Direct Systolic Cardiac Augmentation Device On A Canine Heart During Global Postischemic Dysfunction , Raymond Kenneth Kudej

Retrospective Theses and Dissertations

The performance of a direct systolic cardiac augmentation device, called a heart cuff, was evaluated during application of the device to canine hearts following a period of global ischemia. The heart cuff was developed to provide temporary, partial assistance to a heart experiencing postischemic myocardial dysfunction (myocardial stunning);Myocardial stunning is a postischemic mechanical dysfunction which results from a sublethal tissue injury occurring at the time of reperfusion. The injury will resolve if the myocardial tissue is given sufficient time to recover. Stunning may significantly contribute to the morbidity and mortality of many cardiac procedures because of the temporary inability ...


A Field Portable Ultrasound System For Bovine Tissue Characterization , Kyle Harold Holland Jan 1993

A Field Portable Ultrasound System For Bovine Tissue Characterization , Kyle Harold Holland

Retrospective Theses and Dissertations

Efforts by beef producers and beef packers to reduce carcass losses and to move the industry to a value-based marketing system have renewed their interest in the development of new electronic grading techniques for assessing beef carcass composition. A custom ultrasonic data acquisition system has been developed for the purpose of investigating the feasibility of beef tissue characterization. The unit developed is a compact, hand-held, six channel battery-operated data logger capable of sampling A-mode ultrasound signals at a rate of 15 megasamples per second. A custom epoxy encapsulated ultrasound transducer array was developed to fit the inner curvature of the ...


In Vivo And In Vitro Evaluations Of A Bioactive Ceramic Tooth Root Implant , Gabriele Gruss Niederauer Jan 1993

In Vivo And In Vitro Evaluations Of A Bioactive Ceramic Tooth Root Implant , Gabriele Gruss Niederauer

Retrospective Theses and Dissertations

The objective of this research was to test both the in vitro and in vivo effects of implant surface properties on soft tissue attachment to a bioactive ceramic tooth root implant. The ceramic material used for the tooth root was a composite of tricalcium phosphate and magnesium aluminate spinel, which is called "osteoceramic." For the in vitro cell attachment assays, pure tricalcium phosphate and spinel materials were used in addition to the osteoceramic. The osteoceramic was treated to produce three different surface structures: smooth, irregular and rough. Characterization of the materials included scanning electron microscopy, elemental dispersive analysis, wetting angle ...


Transcranial Doppler Sonography: A New Noninvasive Method For Measuring Toxicant-Induced Alterations In Cerebral Blood Flow , Michael Edward Drues Jan 1992

Transcranial Doppler Sonography: A New Noninvasive Method For Measuring Toxicant-Induced Alterations In Cerebral Blood Flow , Michael Edward Drues

Retrospective Theses and Dissertations

The purpose of this experiment was to use transcranial Doppler sonography (TCD) in the dog to noninvasively measure changes in cerebral blood flow (CBF) resulting from a low-level exposure to the commonly used pyrethroid insecticide deltamethrin. Deltamethrin has previously been shown to increase CBF in rats as determined by other techniques. In this experiment, deltamethrin was dissolved in glycerol-formal solvent and administered intravenously at dosage levels of 5% and 10% of the LD[subscript]50 value to 12 adult dogs 48 hours apart. It was expected that vascular changes resulting from these low-level deltamethrin exposures would be subtle and occur ...


Development Of An Ocular Drug Release System For Cattle , Thomas Quang Dinh Jan 1991

Development Of An Ocular Drug Release System For Cattle , Thomas Quang Dinh

Retrospective Theses and Dissertations

An erodible ring-shaped ocular insert containing an antibiotic (tylosin tartrate) has been developed for treatment of infectious bovine keratoconjunctivitis (IBK). Four additional tasks have been completed: (1) a test to determine the retention time of the ocular device in the eyes of the calves, (2) an in vitro test to determine the degradation characteristics of the device, (3) an in vitro study to obtain the drug release profiles of the insert, and (4) a study to compare the use of rings and a field treatment method using infected cattle;The device remained in the eyes an average of 3.92 ...


Computer Simulation Of Arterial Blood Flow , Nikolaos Stergiopulos Jan 1990

Computer Simulation Of Arterial Blood Flow , Nikolaos Stergiopulos

Retrospective Theses and Dissertations

Computer models have been widely used to simulate pressure and flow propagation in the arterial system. While experimentation involving the human arterial system is difficult and impractical, computer models offer an attractive alternative for the study of arterial hemodynamics. The purpose of the present study was to develop a computer model of the whole systemic circulation and to use this model to study pressure and flow propagation under normal flow conditions, as well as under conditions of arterial disease;The mathematical model used to describe flow in an arterial segment was based on the one-dimensional continuity and momentum equations. The ...