Engineering Commons^™

An Inspiration-Triggered Delivery System For Oxygen Therapy Via A Nasal Cannula, Philip Charles Krause, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Therapy for severe chronic lung disease currently includes the administration of supplemental oxygen to prevent breathlessness and tissue hypoxia. Although effective, this therapy is unnecessarily costly, because oxygen is administered to the patient during expiration as well as inspiration. To eliminate this inefficiency, a delivery system that senses the inspiratory effort and delivers oxygen to the patient only during inspiration was developed. The 11  5  8-cm flow control unit attaches easily to a portable oxygen supply. The components of the system have an expected life of five years, and the 9-Volt battery provides power for about one month …

Use Of Combined Systemic Hypothermia And Local Heat Treatment To Enhance Temperature Differences Between Tumor And Normal Tissues, Charles F. Babbs, William D. Voorhees Iii, Robert R. Clark, David P. Dewitt

Weldon School of Biomedical Engineering Faculty Publications

The feasibility of combining local heat treatment with wholebody hypothermia in an effort to improve therapeutic gain was assessed. Superficial, non perfused phantom tumors were fashioned in eight anesthetized mongrel dogs by transplantation of the spleen from the abdomen to a subcutaneous site on the hind limb. After pretreatment of the animal with the vasodilator hydralazine (0.5 mg/kg, IV) to enhance normal tissue perfusion, the spleen implant was heated with a 2450-MHz microwave diathermy apparatus, first with the animal's core body temperature in the normal range (39°C) and then after the animal had been packed in ice to reduce core …

Endotracheal Versus Intravenous Epinephrine During Electromechanical Dissociation With Cpr In Dogs, Sandra H. Ralston, Willis A. Tacker, Lee Showen, Alice B. Carter, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

The dose-response curves of epinephrine given either IV or endotracheally (ET) were compared during resuscitation from electromechanical dissociation (EMD). Ten anesthetized dogs were subjected to a two-minute period of electrically induced ventricular fibrillation (VF) followed by defibrillation without CPR to produce EMD. Mechanical CPR was followed by injection of either ET or IV epinephrine. Successful response was defined as a return of pulsatile blood pressure within two minutes of drug administration. Using log-dose increments of epinephrine, experimental trials were repeated in each animal. The IV and ET median effective doses were 14 and 130 g/kg, respectively. When the trials were …

Gastric Insufflation During Iac-Cpr And Standard Cpr In A Canine Model, Charles F. Babbs, William E. Schoenlein, Marc W. Lowe

Weldon School of Biomedical Engineering Faculty Publications

This study was undertaken to determine the effect of interposed abdominal compressions (IAC) during cardiopulmonary resuscitation (CPR) on gastric insufflation when the airway is not secured with an endotracheal tube. A canine model was used in which a common ventilation pressure was applied to separate cuffed esophageal and tracheal tubes. Gas entering the stomach was collected by a pre-placed gastrostomy tube leading to a bell spirometer. Gas entering the lungs was measured with a Wright Respirometer® in series with the endotracheal tube. During standard CPR, measurable gastric gas volume was collected in 28 of 30 trials (mean 215  93 …

Electroventilation, L A. Geddes, William D. Voorhees, Charles F. Babbs, J A. Deford

Weldon School of Biomedical Engineering Faculty Publications

Electroventilation is a term used to describe the production of inspiration by applying rhythmic bursts of short duration stimuli to extrathoracic electrodes to stimulate motor nerves to the inspiratory muscles. In the dog, the optimum site for the electrodes was found to be on the upper chest wall, bilaterally. The inspired volume increased with increasing current intensity. The maximum tidal volume attainable was about four times resting tidal volume. The ability of electroventilation to maintain arterial blood oxygen saturation without the production of cardiac arrhythmias was demonstrated in pentobarbital-anesthetized dogs. The technique has several potential applications and offers promise in …

Joseph S. Redding's Contributions To Cardiac Resuscitation, Sandra H. Ralston, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

The experimental studies conducted by the late Joseph S. Redding over the past three decades with his students and colleagues form the scientific basis for many aspects of present cardiopulmonary resuscitation (CPR). Redding's research was characterized by its elegance, simplicity, common-sense reasoning, and clinical relevance. Much of his work conducted in the 1960's anticipated with uncanny accuracy some of the most actively discussed issues in resuscitation today (Table 1). Most interesting are Redding's classic studies related to diastolic arterial pressure and myocardial perfusion during CPR, abdominal binding, acid-base status, and use of methoxamine versus other adrenergic drugs for cardiac resuscitation. …

Interril Soil Erosion, Part I. Development Of Model Equations, John E. Gilley, D. A. Woolheiser, D, B. Mcwhorter

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Equations describing overland flow depth, rainfall induced soil detachment and sediment transport capacity on interrill areas were identified. The Darcy-Weisbach equation which included a parameter for predicting flow resistance caused by rainfall was used to calculate depth of overland flow. Soil detachment was determined from an equation incorporating raindrop induced, impact pressure estimates. The product of a soil transport factor, bottom shear stress and flow velocity was used to calculate sediment transport capacity. Nondimensional forms of the model equations were evaluated using existing experimental data.

Interril Soil Erosion, Part Ii. Testing And Use Of Model Equations, John E. Gilley, D. A. Woolhiser, D. B. Mcwhorter

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Laboratory measurements were made of interrill erosion as affected by varying overland flow discharge and slope slope steepness. Soil detachment and sediment transport capacity relations were then evaluated using experimentally obtained information.

The model equations were utilized to further characterize interrill soil erosion. The overland flow region over which the model equations are applicable for a disturbed Nunn clay loam soil was determined from laboratory tests and critical shear stress analyses. The influence of slope length on interrill erosion was also examined.

Soil Erosion From Tillage Systems Used In Soybean And Corn Residues, Elbert C. Dickey, David P. Shelton, Paul J. Jasa, Thomas Peterson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Rainfall simulation techniques were used to compare soil losses from various tillage systems used on plots where corn and soybeans had been grown the previous season. The two year study was conducted on a silty clay loam soil with a 5% slope and on a silt loam soil with a 10% slope. Five tillage treatments, ranging from a moldboard plow system to no-till, were evaluated for each residue at each site. Tillage and planting operations were conducted up-and-down hill on replicated plots. Total soil loss following 63.5 mm of rainfall applied during a 60 min period averaged more than 40% …

Estimating Crop Residue- Using Residue To Help Control Wind And Water Erosion, Elbert C. Dickey, John Havlin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The Importance of Conservation Tillage

Conservation tillage has been practiced for many years and is becoming increasingly popular with Nebraska farmers. Recent surveys show, about 8 of 19 million cropland acres in Nebraska were farmed with conservation tillage systems. Conservation tillage includes a variety of tillage and planting systems that leave at least 30 percent of the previous crop's residue on the soil surface after planting.

Knowing how to measure or estimate residue cover is an important facet of conservation tillage. A minimum requirement of cover on the soil surface is often specified for U.S. Department of Agriculture programs and …

Soil Compaction I Where, How Bad, A Problem, Elbert C. Dickey, Thomas Peterson, Dean E. Eisenhauer, Paul J. Jasa

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Soil compaction is a more common problem now than it was 15 years ago, regardless of the tillage system used. Producers now use heavier tractors, larger implements, bigger combines, earlier spring tillage, reduced tillage, and no-till planting systems.

While all of these have a potential to increase compaction, the major cause of the problem is conducting field operations when the soil is too wet. Most think about tilling wet soils in the spring as being the major problem, but harvesting a too-wet field in the fall can cause just as much compaction. Large combines and auger wagons can have loads …

Irradiation-Hyperthermia In Canine Hemangiopericytomas: Large-Animal Model For Therapeutic Response, Ralph C. Richardson, Virgil L. Anderson, William D. Voorhees, William E. Blevins, Tammy K. Inskeep, Wolfgang Janas, Robert E. Shupe, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Results of irradiation-hyperthermia treatment in 11 dogs with naturally occurring hemangiopericytomas are reported. Similarities of canine and human hemangiopericytomas are described. Orthovoltage X-irradiation followed by microwaveinduced hyperthermia resulted in a 91% objective response rate. A statistical procedure was given to evaluate quantitatively the clinical behavior of locally invasive, nonmetastatic tumors in dogs that were undergoing therapy for control of local disease. The procedure used a small sample size and demonstrated distribution of the data on a scaled response as well as transformation of the data through classical parametric and nonparametric statistical methods. These statistical methods set confidence limits on the …

Model And Production Function For Irrigation Management, Derrel L. Martin, Darrell G. Watts, James R. Gilley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A simulation model was developed to estimate the effect of deficit irrigation upon crop yield. The model was designed to provide relative yield estimates for numerous combinations of irrigation system, crop growth and irrigation management parameters. A daily soil moisture balance was used to predict evaporation and transpiration from which crop yields were estimated. Gross irrigation water requirements were estimated from net irrigation requirements, irrigation efficiencies, irrigation system limitations, and effective rainfall. Crop production functions that use physically defined parameters were also developed to relate crop yields to gross irrigation requirements. The production functions worked well on a limited test …

Suitability Of Reduced Pressure Center-Pivots, John E. Gilley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Selection criteria for reduced pressure center-pivot irrigation systems are developed. An analysis of the combined effects of the application rate characteristics or center-pivot irrigation systems and the Soil Conservation Service (SCS) soil intake family curves is used to determine the maximum depth of water which could be applied per irrigation for various types of soils and sprinkler packages. These irrigation depths are used to determine guidelines for proper selection of reduced pressure center-pivot systems. The results can be used as a general guide to determine if a particular system may have a runoff problem under a given situation.

An Experimental Circulatory Arrest Model In The Rat To Evaluate Calcium Antagonists In Cerebral Resuscitation, Lawrence De Garavilla, Charles F. Babbs, Willis A. Tacker

Weldon School of Biomedical Engineering Faculty Publications

A circulatory arrest model in the rat was developed for use in cerebral and cardiac resuscitation studies. Whole-body ischemia was produced for 8 to 18 minutes by arresting the heart with a cold potassium chloride cardioplegic solution. Following cardiopulmonary resuscitation, minimal, standardized intensive care was provided. As the duration of ischemia was increased from 8 to 18 minutes, survival immediately following resuscitation decreased from 100% to 25%, and survival at 48 hours after ischemia decreased from 80% to 0%. Thirty per cent of the rats recovering from 11 minutes of ischemia suffered motor seizures. Survival and the incidence of motor …

Regional Blood Flow During Cardiopulmonary Resuscitation With Abdominal Counterpulsation In Dogs, William D. Voorhees Iii, Sandra H. Ralston, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

The addition of abdominal counterpulsation to standard cardiopulmonary resuscitation (IAC-CPR) during ventricular fibrillation has been shown to improve cardiac output, oxygen uptake, and central arterial blood pressure in dogs. The present study was performed to determine the effect of IAC-CPR on regional blood flow. Regional blood flow was measured with radioactively labeled microspheres during sinus rhythm and during alternate periods of IAC-CPR and standard CPR (STD-CPR) in nine dogs anesthetized with pentobarbital. Blood pressures and oxygen uptake were measured continuously. As in previous studies, diastolic arterial pressure was higher (30.8%) during IAC-CPR than during STD-CPR, as were cardiac output (24.5%) …

Preclinical Studies Of Abdominal Counterpulsation In Cpr, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Abdominal counterpulsation added to standard cardiopulmonary resuscitation improves blood flow in animal models when compared to chest compressions alone. Similar effects can be demonstrated in analog and digital computer models of the circulation. The technique generates both central aortic and central venous pressure pulses, and successful application of the method depends on maximizing the former and minimizing the latter. Proper technique is important in order to generate the largest possible arteriovenous pressure difference.

Abnormal Response Of Tumor Vasculature To Vasoactive Drugs, Rosanna C. Chan, Charles F. Babbs, Richard J. Vetter, Carlton H. Lamar

Weldon School of Biomedical Engineering Faculty Publications

The effects of the vasoconstrictor, phenylephrine, and the vasodilator, hydralazine, on blood flow to tumor were studied and compared to those on blood flow to normal tissues in vivo. Regional blood flow and cardiac output were measured with the use of radioactive microspheres in 150- to 250 g inbred Harlan F344 rats bearing subcutaneous nodules of two types of transplantable carcinoma ("hard" and "soft") with microscopically different vascular patterns. Three groups of rats were treated with hydralazine, saline, or phenylephrine, and regional blood flow was determined at the time of maximum blood pressure response. Results were correlated with quantitative morphometric …

Cardiac, Thoracic, And Abdominal Pump Mechanisms In Cardiopulmonary Resuscitation: Studies In An Electrical Model Of The Circulation, Charles F. Babbs, Christopher Weaver, Sandra H. Ralston, Leslie A. Geddes

Weldon School of Biomedical Engineering Faculty Publications

To investigate alternative mechanisms generating artificial circulation during cardiopulmonary resuscitation (CPR), an electrical model of the circulation was developed. Heart and blood vessels were modeled as resistive-capacitive networks; pressures in the chest, abdomen, and vascular compartments as voltages; blood flow as electric current; blood inertia as inductance; and the cardiac and venous valves as diodes. External pressurization of thoracic and abdominal vessels, as would occur in CPR, was simulated by application of half-sinusoidal voltage pulses. Three modes of creating artificial circulation were studied: cardiac pump (CP), in which the atria and ventricles of the model were pressurized simultaneously; thoracic pump …

Intrapulmonary Epinephrine During Prolonged Cardipulmonary Resuscitation: Improved Regional Blood Flow And Resuscitation In Dogs, Sandra H. Ralston, William D. Voorhees, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Blood flow to vital organs was measured at five-minute intervals during 20 minutes of cardiopulmonary resuscitation (CPR) and ventricular fibrillation in two groups of anesthetized dogs (n = 15 per group). The relationship between organ blood flow and restoration of circulation after 20 minutes was assessed with no additional treatment in Group I and with intrapulmonary epinephrine in Group II. Cardiac output and organ blood flow did not vary significantly in Group I. In Group II, intrapulmonary epinephrine significantly improved blood flow to the myocardium, the brain, and the adrenal glands. A mean myocardial blood flow of less than 0.13 …

Theoretical Advantages Of Abdominal Counterpulsation In Cpr As Demonstrated In A Simple Electrical Model Of The Circulation, Charles F. Babbs, Sandra H. Ralston, Leslie A. Geddes

Weldon School of Biomedical Engineering Faculty Publications

Animal studies and preliminary clinical observations suggest that the addition of interposed abdominal compressions (IAC) to ventilation and chest compression of standard cardiopulmonary resuscitation (CPR) augments blood flow, blood pressures, and immediate survival. To investigate the physical basis for enhanced circulation during IAC-CPR, we developed an electrical model of the circulation. Heart and blood vessels were modeled as resistive-capacitive networks, pressures as voltages, blood flow as electric current, blood inertia as inductance, and the cardiac and venous valves as diodes. External pressurization of the heart and great vessels, as would occur in CPR, was simulated by application by half-sinusoidal voltage …

Efficacy And Safety Of The Reciprocal Pulse Defibrillator Current Waveform, M J. Niebauer, Charles F. Babbs, L A. Geddes, J D. Bourland

Weldon School of Biomedical Engineering Faculty Publications

The efficacy and safety of a new defibrillating current waveform, consisting of a low-tilt 5 ms trapezoidal pulse followed closely by a second identical pulse of opposite polarity, was tested m seven isolated, perfused, working canine hearts suspended in an isoresistive, isosmotic shock bath at 37 oC. The efficacy and safety of the reciprocal pulse was compared with a single 5 ms pulse, a single 10 ms pulse, and a dual (unidirectional) 5 ms pulse waveform. The mean threshold average current densities for the 5 ms single pulse, 10 ms single pulse, dual 5 ms pulse, and reciprocal pulse (absolute …

Fuel Ethanol From Raw Corn, Curtis Weller, M. P. Steinberg, E. D. Rodda

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Crude amylase preparations were produced by growing Aspergillus awamori and A. niger on raw, ground, whole corn. These Koji preparations were used to hydrolyze the starch of raw, ground whole corn to sugars during simultaneous fermentation of the sugars to ethanol by distillers active dry yeast. Ethanol concentrations of the fermentation beers were determined with gas-chromatography. These fermentations yielded an average of 89.6% theoretical ethanol compared to control, conventional, fermentations that had an average of 89.9%. Carbon dioxide evolutions were determined with use of Alwood valves. The initial fermentation rate was greater for the conventional fermentation than the Koji fermentation. …

Tillage Influences On Erosion During Furrow Irrigation, Elbert C. Dickey, Dean E. Eisenhauer, Paul J. Jasa

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Erosion and runoff from furrow irrigation of corn was measured for three conventional and three reduced tillage systems in 1981 and 1982. The plots were located on a Hastings silt loam soil having a 0.5% slope and a 366 m furrow length. Erosion was the least for slot-planting and greatest for the chisel system, ranging from 20 to 340 kg/ha, respectively, for the first 45 min of runoff during the first irrigation. Erosion from the fourth irrigation was about 75% less than from the first irrigation. Cumulative runoff after 45 min of runoff was similar for all treatments. Nutrient losses …

Tillage, Residue And Erosion On Moderately Sloping Soils, Elbert C. Dickey, David P. Shelton, Paul J. Jasa, Thomas Peterson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Tillage treatments leaving 20% or more of the soil surface covered with residue reduced soil erosion by at least 50% of that which occurred from a moldboard plow system. No-till had the least erosion and tended to have the lowest cumulative runoff. These results were based on rainfall simulation tests on six tillage treatments used on both 5 and 10% slopes in continuous corn production.

The Application And Effectiveness Of Slow Sand Filtration In The United States, L. A. Slezak, Ronald C. Sims

Biological Engineering Faculty Publications

A survey of 27 slow sand filtration plants in the United States indicated that most of these plants are currently serving communities of fewer than 10 000 persons, are more than 50 years old, and are effective and inexpensive to operate. A slow sand filtration research facility in Logan, Utah, was compared with the operating plants to determine if locally available, unsieved sand achieved similar results. The 75‐m³/d research facility performed well in removing turbidity, coliform bacteria, and particles of a size representative of Giardia cysts.

Human Health Effects Assays, Ronald C. Sims, J. L. Sims, R. R. Dupont

Biological Engineering Faculty Publications

Current development and use of short-term bioassays to evaluate potential human health hazards of environmental chemical exposure has been the focus of the U. S. Environmental Protection Agency (EPA) Second and Third Symposia on the Ap plication of Short-Term Bioassays in the Analysis of Complex Environmental Mixtures.¹'² Topics addressed included development and applications of bioassays, collection and preparation of environmental samples, characterization of hazardous components using bioassays, and environmental assessment. Bartsch and Tomabis,³ using six mutagenicity assays including sub mammalian and mammalian assays to evaluate the quantitative relationship between carcinogenicity and mutagenicity for 532 chemicals, concluded …

Computer Simulation Of The Human Hypophysial-Ovarian System, Robert Charles Blencowe

Theses

In order to more adequately simulate the human pituitary-ovarian cycle further refinements were made to the original Bogumil and Feng computer models. This involved the inclusion of equations which mathematically describe the peripheral conversion of prehormones and a subroutine showing the effect of plasma proteins, TeBG, CBG, and albumin on the total concentration of estradiol, progesterone, testosterone, androstenedione, dehydroepiandrosterone and estrone.

Once the models were functioning properly, values for the normal state and for the disease condition, Polycystic Ovary Syndrome (PCO), were obtained. In most cases there exists good agreement between the results reported in the literature and those generated …

Computer Simulation Of The Respiratory System, Bruce Diner

Theses

The respiratory system was simulated utilizing a series of three models, each more complex than the previous. The first model simulated the respiratory system as a two compartment model driven by carbon dioxide concentration. The second model, also a two compartment model, simulated periodic breathing while the third model is a three compartment model and simulates acid-base balance disturbances.

In this study, the effects of hyperthyroidism and respiratory center depression on respiration premeasured utilizing the models to obtain data and then compare the results to known physiologic data.

Effects Of Myocardial Infarction On Catheter Defibrillation Threshold, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Because the automatic implantable defibrillator may be used in patients having ischemic heart disease, it is important to know whether myocardial ischemia changes the threshold for ventricular defibrillation under experimental conditions simulating automatic internal defibrillation. We determined changes in ventricular defibrillation threshold following coronary occlusion, using an electrode catheter designed for use with an automatic implantable defibrillator. Acute myocardial ischemia was produced without thoracotomy in 10 dogs (experimental group) by embolization with a plastic bead injected via a catheter into the left coronary artery. A control group of 4 dogs had only saline injected into the artery. Defibrillation threshold was …