Biomedical Engineering and Bioengineering Commons^™

The Effect Of Temperature On Polycyclic Aromatic Hydrocarbon Persistence In An Unacclimated Agricultural Soil, M. P. Coover, Ronald C. Sims

Biological Engineering Faculty Publications

A laboratory study was conducted to investigate the effect of temperature on the persistence of polycyclic aromatic hydrocarbons (PAHs) incubated in an unacclimated agricultural sandy loam soil. Soil microcosms were spiked with 16 priority pollutant PAHs and placed in incubation chambers at 10, 20, and 30°C. Triplicate sets of microcosms at each temperature were periodically removed from incubation over the 240 day study period and solvent extracted. Concentrations of PAHs in the soil were determined by HPLC analysis of the extracts. Substantial loss of three-ring compounds was observed at all temperatures whereas there was very little apparent loss of five …

The Rate Of Benzo[A]Pyrene Apparent Loss In A Natural And Manure Amended Clay Loam Soil, M. P. Coover, Ronald C. Sims

Biological Engineering Faculty Publications

A study was conducted to evaluate the rate of Benzo[a]pyrene apparent loss from a previously uncontaminated agricultural clay loam soil and to determine the effect of cow manure, as organic substrate amendment, on B[a]P apparent loss. Soil microcosms were spiked with 10 μg/g B[a]P and incubated at 20°C. Triplicate sets of microcosms were periodically removed from incubation and solvent extracted. Concentrations of B[a]P in the soil were determined by HPLC analysis of the extracts. Under the conditions of this study manure was an ineffective amendment for increasing the rate of B[a]P apparent loss in the Durant clay loam soil. In …

Conservation Tillage: Perceived And Actual Use, Elbert C. Dickey, Paul J. Jasa, Bryn J. Dolesh, Lisa A. Brown, S. Kay Rockwell

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A mail survey of farmers in Nebraska showed their perceived use of conservation tillage was about 55%. However, using the 30% residue cover criterion that the Conservation Tillage Information Center uses to define conservation tillage, a field survey of seven counties in 1984 showed that actual use of conservation tillage was less than 5%. Fewer than 20% of the producers surveyed had more than 20% residue cover remaining after tillage and planting. The field survey also showed disk tillage systems were used by almost 70% of the producers. The moldboard plow was used by only 15% of the producers, thus …

Colorimetric Assay For Methanesulfinic Acid In Biological Samples, Charles F. Babbs, Melissa J. Gale

Weldon School of Biomedical Engineering Faculty Publications

We describe a simple colorimetric method to measure 30 to 300 M concentrations of sulfinic acids in biologic samples. The procedure employs the coupling reaction of an aromatic diazonium salt (Ar-N=N+) with the sulfinic acids (RSOOH) to produce a colored diazosulfone derivative (Ar-N=N-SOOR), which can be selectively extracted into an organic solvent. Linearity and noninterference by liver homogenate, phenols, amines, and thousand-fold or greater excesses of sulfate, thiol, and dimethyl sulfoxide are demonstrated. Sensitivity of the method is about 10 nmol per sample. Because methanesulfinic acid is the principal product of the action of hydroxyl radicals upon dimethyl sulfoxide, and …

Protection From Reperfusion Injury In The Isolated Rat Heart By Postischaemic Deferoxamine And Osypurinol Administration, Stephen F. Badylak, Abby Simmons, John Turek, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

The Langendorff isolated rat heart preparation was used to determine the effect of oxypurinol, a xanthine oxidase inhibitor, and deferoxamine, an iron binding agent, on the extent of myocardial reperfusion injury after 60 minutes of ischaemia. Thirty rats were divided into three groups of 10. and an isolated heart preparation made from each rat. The isolated hearts were perfused for 15 minutes with a modified Krebs-Henseleit perfusate solution to permit stabilisation of the preparation. Each heart was then subjected to 60 minutes of total ischaemia at 37°C followed by 60 minutes of reperfusion with either saline treated perfusate, oxypurinol treated …

Slope Length And Surface Residue Influences On Runoff And Erosion, John E. Gilley, S. C. Finkner, G. E. Varvel

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Runoff rate, runoff velocity , sediment concentration and soil loss rate of rills or overland flow channels were measured at selected downslope distances on plots with varying rates of sorghum and soybean residue, runoff rate, runoff velocity and soil loss rate usually increased with downslope distance. In general, the presence of greater amounts of crop residue reduced sediment concentration and soil loss rate along the entire slope length. Substantial variations in runoff rate, runoff velocity, sediment concentration and soil loss rate were found with downslope distance on some residue treatments.

Slot Injection Of Herbicides, Paul J. Jasa, Elbert C. Dickey, Thomas R. Peterson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Injection of thiocarbamate herbicides into a slot created by a coulter was evaluated during a 3-year study in southeastern Nebraska. Control of shattercane, the dominant weed, with the slot injector was similar to conventional double disk incorporation. In both tilled and untilled surface conditions, the slot injector placed the herbicide into the soil with minimal disturbance of the soil and residue. Herbicides which are normally broadcast applied were band applied, reducing chemical costs by two-thirds.

Multistep Measurement Of Plantar Pressure Alterations Using Metatarsal Pads, An-Hsiung Chang, Ziad U. Abu-Faraj, Gerald F. Harris, Joe Nery, Michael J. Shereff

Biomedical Engineering Faculty Research and Publications

Metatarsal pads are frequently prescribed for nonoperative management of metatarsalgia due to various etiologies. When appropriately placed, they are effective in reducing pressures under the metatarsal heads on the plantar surface of the foot. Despite the positive clinical reports that have been cited, there are no quantitative studies documenting the load redistribution effects of these pads during multiple step usage within the shoe environment. The objective of this study was to assess changes in plantar pressure metrics resulting from pad use. Ten normal adult male subjects were tested during a series of 400-step trials. Pressures were recorded from eight discrete …

Runoff And Erosion As Affected By Sorghum And Soybean Residue, John E. Gilley, S. C. Finkner, G. E. Varvel

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A rainfall simulator was used to measure the effects of varying rates of sorghum and soybean residue on runoff and erosion. In general, increased surface cover caused reduced runoff, sediment concentration and soil loss. Substantial reductions in erosion resulted from the use of small amounts of crop residue. Regression equations were obtained which related surface cover to residue mass. Equations describing relative runoff, sediment concentration and soil loss as a function of surface cover were also developed. Runoff, sediment concentration and soil loss were all found to be highly correlated to surface cover.

Size Distribution Of Sediment As Affected By Corn Residue, John E. Gilley, S. C. Finkner, R. G. Spomer, L. N. Mielke

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Size distribution of sediment was measured under simulated rainfall conditions at selected downslope distances on plots with corn residue rates ranging from 0.00 to 6.73 t/ha. The formation of rills caused increases in the percentage of larger sized sediment material. Greater surface cover usually resulted in an increase in the percentage of smaller sized sediment.

Considerable variation in the size of sediment from both rill and interrill areas was found with downslope distance. On interrill regions, the presence of residue served to reduce sediment size along the entire plot length. Transport of aggregated sediment occurred on each of the residue …

The Effect Of Systemic Arterial Pressure On Microvascular Flow And Transcapillary Exchange Of Macromolecules In The Hamster Cheek Pouc, Govind Mohanlal Gawdi

Theses

Microvascular flow velocities and transport of macromolecules were studied in the hamster cheek pouch under control and acute high arterial pressure conditions, with or without topical (local) application of the vasodilating agent, bradykinin. Mean arterial pressures of 130-160% control were attained by intravenous renin infusion. The microcirculation of the cheek pouch was studied using intravital microscopy. Areas with arterioles and venules were recorded on a videotape for later analysis of red cell velocity, using an RBC tracking correlator, and vessel diameter using a video shearing monitor.

In addition, vascular permeability to macromolecules was studied in the hamster cheek pouch vascular …

In Vitro Comparative Hydrodynamic Study Of Heart Valve Bioprostheses Under Accelerated Fatigue Conditions And Under Physiological Conditions, Mario Cincinat Iosif

Theses

The present study involves the use of an accelerated fatigue testing system*, and a pulse duplicator (heart simulator)*, to evaluate the hydrodynamic characteristics of cardiac bioprostheses.

The hydrodynamic performance of these prosthetic valves is compared when tested using each machine, in order to assess the determining conditions that exist for each case, and try to correlate them.

Pressure drop and pulsatile flow across valves are measured, using a real-time on-line data acquisition system, which includes, in addition to the fatigue tester and the pulse duplicator, a DC amplifier, an analog-to-digital converter and a digital microcomputer. Special acquisition software has been …

Effects Of Physical Exertion And Caffeine Ingestion On Mental Performance, Alireza Shafiei

Theses

Stresses in man-machine systems can be broadly classified as (1) physical and (2) mental. Both types of stresses generate some kind of response in the human body. These responses could be physiological (quantitative) or behavioral (qualitative). While the physical stresses mostly create physiological changes, mental stresses may cause physiological and/or behavioral changes. The purpose of this study is to investigate such influences, and try to determine if stimulants such as coffee have any effect on people's ability to perform tasks involving a combination of physical and mental elements.

An attempt has been made to describe an interrelationship between physical exertion …

Preparation And Testing Of Novel Blocked Isocyanate Dental Adhesives Based Upon Hydroxyhexylmethacrylate, Gururajan Rao

Theses

In this study dental adhesives synthesised from TDI/HHMA/pentaerythritol, with either of the blocking agents namely eugenol, o-methoxyphenol, p-cresol or o-chlorophenol were tested. Bond strengths in dentin as influenced by spacer molecules were tested. Comparison studies to determine this were performed using the same blocking agents and TDI/HEMA/pentaerythritol. The effects of i. post-extraction time and ii. dentin depth on bond-strengths were tested using two monomers: o-methoxyphenol/ TDI/HEMA/pentaerythritol and p-cresol/TDI/HEMA/pentaerythritol 1. From teeth recently extracted (2h) vs dentin aged from one to six months 2. From dentin cut from three different levels within the tooth.

The prepared dentin-adhesive samples were stored in …

A Predictive-Adaptive, Multipoint Feedback Controller For Local Heat Therapy Of Solid Tumors, Charles F. Babbs, V A. Vanguine, J T. Jones

Weldon School of Biomedical Engineering Faculty Publications

Uniform heating of tumor tissue to therapeutic temperatures without damaging surrounding normal tissue is required for optimal local heat therapy of cancer. This paper describes an algorithm for online computer control that will allow the therapist to minimize the standard deviation of measured intratumoral temperatures. The method is applicable to systems incorporating multiple surface and/or interstitial applicators delivering microwave, radiofrequency, or ultrasonic power and operating under the control of a small computer. The essential element is a novel predictive-adaptive control algorithm that infers relevant thermal parameters from the responses of multiple temperature sensors, as each of the power applicators is …

Tillage Systems For Row Crop Production, Elbert C. Dickey, Paul J. Jasa, Alice J. Jones, David P. Shelton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Selecting the tillage system best suited to a particular farming situation is an important management decision. Formerly, the traditional system was a moldboard plow operation followed by several secondary tillage operations before planting. This system can be appropriate for poorly drained soils having little or no slope and low erosion potential. However, plowing has several disadvantages . The potential for soil erosion is high on sloping lands, and labor and fuel requirements can be substantially higher than with other tillage and planting systems.

Today, conservation tillage systems are used to reduce preplant tillage operations, thus reducing soil erosion and moisture …

Microcomputer-Based System For The Measurement Of Facial Swelling, Michael Guy Demuth

Theses

The measurement of facial swelling after oral surgery can indicate the effect of anti-inflammatory drugs. A mechanical device was interfaced to a microcomputer to allow faster calculation of swelling. The mechanical system first established X and Y coordinates on the face. A feeler arm traced out the facial contours and two linear variable differential transformers (LVDTs) related X and Y displacements to voltages which were fed into a microcomputer via an A/D converter. Three BASIC programs were written which facilitated the analysis of patient swelling. MEASUREMENT stored the X-Y voltages from the LVDTs in a patient disk file. CALCULATION filtered …

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

Biological Engineering Faculty Publications

Discussion of the exponential increase in environmental toxicological information and an approach for organizing and using the information was presented by Lu and Wassom.¹ A user's guide to the Registry of Toxic Effects of Chemical Substances (RTECS) was published by NIOSH² that defines the record layouts and describes the types of data contained in the computer tape version of the 1984 Edition of the RTECS.³ A text summarizing information on approximately 800 toxic chemicals was edited by Sittig.⁴ Milestone publications concerning fundamentals of toxicology with environmental applications included the works of Gentile,⁵ Ashby,⁶ Mortel …

Review And Evaluation Of Current Design And Management Practices For Land Treatment Units Receiving Petroleum Wastes, J. P. Martin, Ronald C. Sims, J. Matthews

Biological Engineering Faculty Publications

Land treatment is categorized in the Resource Conservation and Recovery Act of 1976 (RCRA) as one of the land disposal options for managing hazardous wastes. Land treatment relies on detoxification, degradation, and immobilization of hazardous waste constituents within the defined treatment zone to ensure protection of surface water, groundwater, and air. Under the authority of Subtitle C of RCRA, the U.S. Environmental Protection Agency has promulgated regulations governing the treatment of hazardous wastes in land treatment units (40 CRF, Part 264, Subpart M, July, 1982).

This paper describes the land treatment practices used by petroleum waste land treatment facilities in …

Sediment And Dye Concentration Effects On Fluorescence, S. C. Finkner, John E. Gilley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Because of the relatively large sediment concentrations sometimes found on upland regions, adsorption of fluorescent dye onto sediment may be of concern. A laboratory study was conducted to identify the effects of sediment and dye concentration on adsorption. Sediment and dye concentration were both found to significantly affect adsorptive dye loss of rhodamine WT and sulpho rhodamine B.
Regression equations were developed which related dye adsorption to sediment and dye concentration. For a particular soil and dye material, regression equations may be used to correct for adsorptive dye loss. Sulpho rhodamine B is recommended as the dye of choice for …

Soil Erosion From Tillage And Planting Systems Used In Soybean Residue: Part I - Influences Of Row Spacing, David P. Shelton, Paul J. Jasa, Elbert C. Dickey

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A rainfall simulator was used to compare soil losses from various tillage and planting systems used in residue from soybeans which had been grown in both wide and narrow spaced rows the previous season. Up and- down hill tillage and planting treatments ranging from a double disk system to no-till planting were evaluated using replicated plots on a silt loam soil in the Nora Series having a 10% slope.

Tillage and planting systems used in soybean residue from narrow spaced rows had soil erosion and soil erosion rates that were reduced by approximately 50% compared to the same systems used …

Soil Erosion From Tillage And Planting Systems Used In Soybean Residue: Part Ii - Influences Of Row Direction, Paul J. Jasa, Elbert C. Dickey, David P. Shelton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A rainfall simulator was used to compare soil losses from tillage and planting systems used in residue from soybeans. The study was conducted on a silty clay loam soil in the Wymore Series with a 5% slope and on a silt loam soil in the Nora Series with a 10% slope. Tillage and planting treatments, ranging from a moldboard plow system to no-till planting, were evaluated both up and- down hill and on the contour using replicated plots.

For the first rainfall event after tillage and planting, the average soil loss for all systems on the contour was 3.0 t/ha …

Runoff And Erosion As Affected By Corn Residue: Prt Ii: Rill And Interill Components, John E. Gilley, S. C. Finkner, R. G. Spomer, L. N. Mielke

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Hydraulic and soil loss variables were measured under simulated rainfall conditions at selected downslope distances on plots with corn residue rates ranging from 0.0 to 6.7 t/ha. Application of corn residue produced substantial reductions in runoff rate, runoff velocity, sediment concentration and soil loss rate along the entire slope length. On those plots subject to rilling, runoff rate, sediment concentration and soil loss rate usually increased with downslope distance.

Rill and interrill sediment concentration and soil loss rate were also measured at selected slope lengths. lnterrill sediment concentration changed little with downslope distance while greater interrill soil loss rates were …

Estimating Residue Cover, Elbert C. Dickey, Paul J. Jasa, David P. Shelton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Crop residue management through conservation tillage is one of the best and most efficient methods farmers have to control soil erosion. Each year about 140 million tons of topsoil are eroded from Nebraska farmlands. Recent research shows that farmers can greatly reduce this loss by maintaining a residue cover of at least 20 to 30 percent after all tillage and planting operations. Leaving this amount of residue can reduce water caused erosion by 50 percent of what it would be from a cleanly tilled field, while leaving more residue will reduce soil losses even further. Conservation tillage and residue management …

Effect Of Deferoxamine On Late Deaths Following Cpr In Rats, Charles F. Babbs, Sushil D. Kompala, Karl E. Blaho

Weldon School of Biomedical Engineering Faculty Publications

The iron chelating agent deferoxamine was studied in an animal model as post-resuscitation therapy to prevent late deaths and brain damage following total circulatory arrest and resuscitation. Cardio-respiratory arrest was induced by injection of cold, 1% KC1 into the left ventricles of ketamine anesthetized rats pretreated with succinylcholine chloride, and by discontinuation of positive pressure ventilation. CPR was begun after six minutes, and animals with return of spontaneous circulation were entered into the study. Within five minutes after return of spontaneous circulation, treated animals received deferoxamine (50 mg/kg, IV). At ten days, 16 of 25 (64%) of treated animals had …

Relationship Between Pulse-Wave Velocity And Arterial Elasticity, F J. Callaghan, L A. Geddes, Charles F. Babbs, J D. Bourland

Weldon School of Biomedical Engineering Faculty Publications

Pulse wave velocity (PWV) was measured in situ in 11 isolated canine common carotid arteries. Seven arteries exhibited a linear PWV vs. pressure function at pressures ranging from 0 to 200 mmHg. Four arteries yielded a linear relationship between PWV and pressure between 1 and 100 mmHg; for these vessels the relationship was nonlinear at higher pressures. Seven arteries (five from the group which was linear up to 200 mmHg and two from the group which was linear up to 100 mmHg) were excised and pressure/volume measurements were made in vivo. Using pressure/volume data, the Moens-Korteweg equation was evaluated as …

Potassium Efflux From Myocardial Cells Induced By Defibrillator Shock, M J. Niebauer, L A. Geddes, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

A transient, dose-dependent cardiac depression was produced by defibrillator shocks in an isolated, working canine heart preparation perfused with oxygenated arterial blood from a support dog. Accompanying this depression was an efflux of potassium (K+ ), forced out of the myocardial cells by the passage of defibrillating current. The transient increase in extracellular K + concentration was recorded graphically in the venous outflow. It was found that 5-msec rectangular wave shocks, from three to ten times defibrillatory current threshold, released doserelated pulses of K+ . We conclude that because extracellular K + is a myocardial depressant, at least part of …

The Effect Of Carbon Dioxide, Lidoflazine, And Deferoxamine Upon Long Term Survival Following Cardiorespiratory Arrest In Rats, Stephen F. Badylak, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

This study examined the effect of carbon dioxide, lidoflazine, and deferoxamine therapy upon the 10-day survival incidence and subsequent neurologic function of rats subjected to 7 min of cardiorespiratory arrest with resuscitation. Cardiac arrest (asystole) was induced at time zero by injection of cold, 1% KCl into the left ventricle of ketamine-anesthetized rats pretreated with succinylcholine. Positive pressure ventilation was discontinued at time zero. Cardiopulmonary resuscitation (CPR) was begun at 7 min, and animals with return of spontaneous circulation were entered into the study. Twenty treated rats were ventilated for 1 h with 7% carbon dioxide-93% oxygen and given lidoflazine …

Abdominal Binding And Counterpulsation In Cardiopulmonary Resuscitation, Charles F. Babbs, William E. Blevins

Weldon School of Biomedical Engineering Faculty Publications

The history and potential of abdominal pressure as an adjunct to standard cardiopulmonary resuscitation (CPR) is reviewed. Abdominal pressure during CPR may be either static or phasic. Static abdominal pressure redirects limited blood flow generated by chest compressions toward the heart and brain, and away from the abdominal organs and lower extremities, thus boosting coronary perfusion pressure. Phasic abdominal pressure applied whenever chest pressure is released, in counterpoint to the rhythm of chest compression—so called interposed abdominal compression (IAC)-CPR—generates blood flow by an independent abdominal pump mechanism that augments the systemic perfusion created by chest compressions. New imaging data are …

Runoff And Erosion As Affected By Corn Residue: Part I. Total Losses, John E. Gilley, S. C. Finkner, R. G. Spomer, L. N. Mielke

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The effects of verying rates of corn residue on runoff and erosion from a loess soil in southwestern Iowa were measured using a rainfall simulator. Consistent reductions in runoff, sediment concentration and soil loss resulted from increased residue application. Small amounts of surface cover produced substantial reductions in erosion. A regression equation relating surface cover to residue weight was obtained. Equations describing relative runoff, sediment concentration and soil loss as a function of surface cover were also developed using regression analysis.